fs/btrfs/volumes.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/bio.h>
  20 #include <linux/slab.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/random.h>
  24 #include <linux/iocontext.h>
  25 #include <linux/capability.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/kthread.h>
  28 #include <linux/raid/pq.h>
  29 #include <asm/div64.h>
  30 #include "compat.h"
  31 #include "ctree.h"
  32 #include "extent_map.h"
  33 #include "disk-io.h"
  34 #include "transaction.h"
  35 #include "print-tree.h"
  36 #include "volumes.h"
  37 #include "raid56.h"
  38 #include "async-thread.h"
  39 #include "check-integrity.h"
  40 #include "rcu-string.h"
  41 #include "math.h"
  42 #include "dev-replace.h"
  43
  44 static int init_first_rw_device(struct btrfs_trans_handle *trans,
  45                                 struct btrfs_root *root,
  46                                 struct btrfs_device *device);
  47 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
  48 static void __btrfs_reset_dev_stats(struct btrfs_device *dev);
  49 static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev);
  50 static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);
  51
  52 static DEFINE_MUTEX(uuid_mutex);
  53 static LIST_HEAD(fs_uuids);
  54
  55 static void lock_chunks(struct btrfs_root *root)
  56 {
  57         mutex_lock(&root->fs_info->chunk_mutex);
  58 }
  59
  60 static void unlock_chunks(struct btrfs_root *root)
  61 {
  62         mutex_unlock(&root->fs_info->chunk_mutex);
  63 }
  64
  65 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
  66 {
  67         struct btrfs_device *device;
  68         WARN_ON(fs_devices->opened);
  69         while (!list_empty(&fs_devices->devices)) {
  70                 device = list_entry(fs_devices->devices.next,
  71                                     struct btrfs_device, dev_list);
  72                 list_del(&device->dev_list);
  73                 rcu_string_free(device->name);
  74                 kfree(device);
  75         }
  76         kfree(fs_devices);
  77 }
  78
  79 static void btrfs_kobject_uevent(struct block_device *bdev,
  80                                  enum kobject_action action)
  81 {
  82         int ret;
  83
  84         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
  85         if (ret)
  86                 pr_warn("Sending event '%d' to kobject: '%s' (%p): failed\n",
  87                         action,
  88                         kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
  89                         &disk_to_dev(bdev->bd_disk)->kobj);
  90 }
  91
  92 void btrfs_cleanup_fs_uuids(void)
  93 {
  94         struct btrfs_fs_devices *fs_devices;
  95
  96         while (!list_empty(&fs_uuids)) {
  97                 fs_devices = list_entry(fs_uuids.next,
  98                                         struct btrfs_fs_devices, list);
  99                 list_del(&fs_devices->list);
 100                 free_fs_devices(fs_devices);
 101         }
 102 }
 103
 104 static noinline struct btrfs_device *__find_device(struct list_head *head,
 105                                                    u64 devid, u8 *uuid)
 106 {
 107         struct btrfs_device *dev;
 108
 109         list_for_each_entry(dev, head, dev_list) {
 110                 if (dev->devid == devid &&
 111                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
 112                         return dev;
 113                 }
 114         }
 115         return NULL;
 116 }
 117
 118 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
 119 {
 120         struct btrfs_fs_devices *fs_devices;
 121
 122         list_for_each_entry(fs_devices, &fs_uuids, list) {
 123                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
 124                         return fs_devices;
 125         }
 126         return NULL;
 127 }
 128
 129 static int
 130 btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
 131                       int flush, struct block_device **bdev,
 132                       struct buffer_head **bh)
 133 {
 134         int ret;
 135
 136         *bdev = blkdev_get_by_path(device_path, flags, holder);
 137
 138         if (IS_ERR(*bdev)) {
 139                 ret = PTR_ERR(*bdev);
 140                 printk(KERN_INFO "btrfs: open %s failed\n", device_path);
 141                 goto error;
 142         }
 143
 144         if (flush)
 145                 filemap_write_and_wait((*bdev)->bd_inode->i_mapping);
 146         ret = set_blocksize(*bdev, 4096);
 147         if (ret) {
 148                 blkdev_put(*bdev, flags);
 149                 goto error;
 150         }
 151         invalidate_bdev(*bdev);
 152         *bh = btrfs_read_dev_super(*bdev);
 153         if (!*bh) {
 154                 ret = -EINVAL;
 155                 blkdev_put(*bdev, flags);
 156                 goto error;
 157         }
 158
 159         return 0;
 160
 161 error:
 162         *bdev = NULL;
 163         *bh = NULL;
 164         return ret;
 165 }
 166
 167 static void requeue_list(struct btrfs_pending_bios *pending_bios,
 168                         struct bio *head, struct bio *tail)
 169 {
 170
 171         struct bio *old_head;
 172
 173         old_head = pending_bios->head;
 174         pending_bios->head = head;
 175         if (pending_bios->tail)
 176                 tail->bi_next = old_head;
 177         else
 178                 pending_bios->tail = tail;
 179 }
 180
 181 /*
 182  * we try to collect pending bios for a device so we don't get a large
 183  * number of procs sending bios down to the same device.  This greatly
 184  * improves the schedulers ability to collect and merge the bios.
 185  *
 186  * But, it also turns into a long list of bios to process and that is sure
 187  * to eventually make the worker thread block.  The solution here is to
 188  * make some progress and then put this work struct back at the end of
 189  * the list if the block device is congested.  This way, multiple devices
 190  * can make progress from a single worker thread.
 191  */
 192 static noinline void run_scheduled_bios(struct btrfs_device *device)
 193 {
 194         struct bio *pending;
 195         struct backing_dev_info *bdi;
 196         struct btrfs_fs_info *fs_info;
 197         struct btrfs_pending_bios *pending_bios;
 198         struct bio *tail;
 199         struct bio *cur;
 200         int again = 0;
 201         unsigned long num_run;
 202         unsigned long batch_run = 0;
 203         unsigned long limit;
 204         unsigned long last_waited = 0;
 205         int force_reg = 0;
 206         int sync_pending = 0;
 207         struct blk_plug plug;
 208
 209         /*
 210          * this function runs all the bios we've collected for
 211          * a particular device.  We don't want to wander off to
 212          * another device without first sending all of these down.
 213          * So, setup a plug here and finish it off before we return
 214          */
 215         blk_start_plug(&plug);
 216
 217         bdi = blk_get_backing_dev_info(device->bdev);
 218         fs_info = device->dev_root->fs_info;
 219         limit = btrfs_async_submit_limit(fs_info);
 220         limit = limit * 2 / 3;
 221
 222 loop:
 223         spin_lock(&device->io_lock);
 224
 225 loop_lock:
 226         num_run = 0;
 227
 228         /* take all the bios off the list at once and process them
 229          * later on (without the lock held).  But, remember the
 230          * tail and other pointers so the bios can be properly reinserted
 231          * into the list if we hit congestion
 232          */
 233         if (!force_reg && device->pending_sync_bios.head) {
 234                 pending_bios = &device->pending_sync_bios;
 235                 force_reg = 1;
 236         } else {
 237                 pending_bios = &device->pending_bios;
 238                 force_reg = 0;
 239         }
 240
 241         pending = pending_bios->head;
 242         tail = pending_bios->tail;
 243         WARN_ON(pending && !tail);
 244
 245         /*
 246          * if pending was null this time around, no bios need processing
 247          * at all and we can stop.  Otherwise it'll loop back up again
 248          * and do an additional check so no bios are missed.
 249          *
 250          * device->running_pending is used to synchronize with the
 251          * schedule_bio code.
 252          */
 253         if (device->pending_sync_bios.head == NULL &&
 254             device->pending_bios.head == NULL) {
 255                 again = 0;
 256                 device->running_pending = 0;
 257         } else {
 258                 again = 1;
 259                 device->running_pending = 1;
 260         }
 261
 262         pending_bios->head = NULL;
 263         pending_bios->tail = NULL;
 264
 265         spin_unlock(&device->io_lock);
 266
 267         while (pending) {
 268
 269                 rmb();
 270                 /* we want to work on both lists, but do more bios on the
 271                  * sync list than the regular list
 272                  */
 273                 if ((num_run > 32 &&
 274                     pending_bios != &device->pending_sync_bios &&
 275                     device->pending_sync_bios.head) ||
 276                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
 277                     device->pending_bios.head)) {
 278                         spin_lock(&device->io_lock);
 279                         requeue_list(pending_bios, pending, tail);
 280                         goto loop_lock;
 281                 }
 282
 283                 cur = pending;
 284                 pending = pending->bi_next;
 285                 cur->bi_next = NULL;
 286
 287                 if (atomic_dec_return(&fs_info->nr_async_bios) < limit &&
 288                     waitqueue_active(&fs_info->async_submit_wait))
 289                         wake_up(&fs_info->async_submit_wait);
 290
 291                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
 292
 293                 /*
 294                  * if we're doing the sync list, record that our
 295                  * plug has some sync requests on it
 296                  *
 297                  * If we're doing the regular list and there are
 298                  * sync requests sitting around, unplug before
 299                  * we add more
 300                  */
 301                 if (pending_bios == &device->pending_sync_bios) {
 302                         sync_pending = 1;
 303                 } else if (sync_pending) {
 304                         blk_finish_plug(&plug);
 305                         blk_start_plug(&plug);
 306                         sync_pending = 0;
 307                 }
 308
 309                 btrfsic_submit_bio(cur->bi_rw, cur);
 310                 num_run++;
 311                 batch_run++;
 312                 if (need_resched())
 313                         cond_resched();
 314
 315                 /*
 316                  * we made progress, there is more work to do and the bdi
 317                  * is now congested.  Back off and let other work structs
 318                  * run instead
 319                  */
 320                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
 321                     fs_info->fs_devices->open_devices > 1) {
 322                         struct io_context *ioc;
 323
 324                         ioc = current->io_context;
 325
 326                         /*
 327                          * the main goal here is that we don't want to
 328                          * block if we're going to be able to submit
 329                          * more requests without blocking.
 330                          *
 331                          * This code does two great things, it pokes into
 332                          * the elevator code from a filesystem _and_
 333                          * it makes assumptions about how batching works.
 334                          */
 335                         if (ioc && ioc->nr_batch_requests > 0 &&
 336                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
 337                             (last_waited == 0 ||
 338                              ioc->last_waited == last_waited)) {
 339                                 /*
 340                                  * we want to go through our batch of
 341                                  * requests and stop.  So, we copy out
 342                                  * the ioc->last_waited time and test
 343                                  * against it before looping
 344                                  */
 345                                 last_waited = ioc->last_waited;
 346                                 if (need_resched())
 347                                         cond_resched();
 348                                 continue;
 349                         }
 350                         spin_lock(&device->io_lock);
 351                         requeue_list(pending_bios, pending, tail);
 352                         device->running_pending = 1;
 353
 354                         spin_unlock(&device->io_lock);
 355                         btrfs_requeue_work(&device->work);
 356                         goto done;
 357                 }
 358                 /* unplug every 64 requests just for good measure */
 359                 if (batch_run % 64 == 0) {
 360                         blk_finish_plug(&plug);
 361                         blk_start_plug(&plug);
 362                         sync_pending = 0;
 363                 }
 364         }
 365
 366         cond_resched();
 367         if (again)
 368                 goto loop;
 369
 370         spin_lock(&device->io_lock);
 371         if (device->pending_bios.head || device->pending_sync_bios.head)
 372                 goto loop_lock;
 373         spin_unlock(&device->io_lock);
 374
 375 done:
 376         blk_finish_plug(&plug);
 377 }
 378
 379 static void pending_bios_fn(struct btrfs_work *work)
 380 {
 381         struct btrfs_device *device;
 382
 383         device = container_of(work, struct btrfs_device, work);
 384         run_scheduled_bios(device);
 385 }
 386
 387 static noinline int device_list_add(const char *path,
 388                            struct btrfs_super_block *disk_super,
 389                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 390 {
 391         struct btrfs_device *device;
 392         struct btrfs_fs_devices *fs_devices;
 393         struct rcu_string *name;
 394         u64 found_transid = btrfs_super_generation(disk_super);
 395
 396         fs_devices = find_fsid(disk_super->fsid);
 397         if (!fs_devices) {
 398                 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 399                 if (!fs_devices)
 400                         return -ENOMEM;
 401                 INIT_LIST_HEAD(&fs_devices->devices);
 402                 INIT_LIST_HEAD(&fs_devices->alloc_list);
 403                 list_add(&fs_devices->list, &fs_uuids);
 404                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
 405                 fs_devices->latest_devid = devid;
 406                 fs_devices->latest_trans = found_transid;
 407                 mutex_init(&fs_devices->device_list_mutex);
 408                 device = NULL;
 409         } else {
 410                 device = __find_device(&fs_devices->devices, devid,
 411                                        disk_super->dev_item.uuid);
 412         }
 413         if (!device) {
 414                 if (fs_devices->opened)
 415                         return -EBUSY;
 416
 417                 device = kzalloc(sizeof(*device), GFP_NOFS);
 418                 if (!device) {
 419                         /* we can safely leave the fs_devices entry around */
 420                         return -ENOMEM;
 421                 }
 422                 device->devid = devid;
 423                 device->dev_stats_valid = 0;
 424                 device->work.func = pending_bios_fn;
 425                 memcpy(device->uuid, disk_super->dev_item.uuid,
 426                        BTRFS_UUID_SIZE);
 427                 spin_lock_init(&device->io_lock);
 428
 429                 name = rcu_string_strdup(path, GFP_NOFS);
 430                 if (!name) {
 431                         kfree(device);
 432                         return -ENOMEM;
 433                 }
 434                 rcu_assign_pointer(device->name, name);
 435                 INIT_LIST_HEAD(&device->dev_alloc_list);
 436
 437                 /* init readahead state */
 438                 spin_lock_init(&device->reada_lock);
 439                 device->reada_curr_zone = NULL;
 440                 atomic_set(&device->reada_in_flight, 0);
 441                 device->reada_next = 0;
 442                 INIT_RADIX_TREE(&device->reada_zones, GFP_NOFS & ~__GFP_WAIT);
 443                 INIT_RADIX_TREE(&device->reada_extents, GFP_NOFS & ~__GFP_WAIT);
 444
 445                 mutex_lock(&fs_devices->device_list_mutex);
 446                 list_add_rcu(&device->dev_list, &fs_devices->devices);
 447                 mutex_unlock(&fs_devices->device_list_mutex);
 448
 449                 device->fs_devices = fs_devices;
 450                 fs_devices->num_devices++;
 451         } else if (!device->name || strcmp(device->name->str, path)) {
 452                 name = rcu_string_strdup(path, GFP_NOFS);
 453                 if (!name)
 454                         return -ENOMEM;
 455                 rcu_string_free(device->name);
 456                 rcu_assign_pointer(device->name, name);
 457                 if (device->missing) {
 458                         fs_devices->missing_devices--;
 459                         device->missing = 0;
 460                 }
 461         }
 462
 463         if (found_transid > fs_devices->latest_trans) {
 464                 fs_devices->latest_devid = devid;
 465                 fs_devices->latest_trans = found_transid;
 466         }
 467         *fs_devices_ret = fs_devices;
 468         return 0;
 469 }
 470
 471 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
 472 {
 473         struct btrfs_fs_devices *fs_devices;
 474         struct btrfs_device *device;
 475         struct btrfs_device *orig_dev;
 476
 477         fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 478         if (!fs_devices)
 479                 return ERR_PTR(-ENOMEM);
 480
 481         INIT_LIST_HEAD(&fs_devices->devices);
 482         INIT_LIST_HEAD(&fs_devices->alloc_list);
 483         INIT_LIST_HEAD(&fs_devices->list);
 484         mutex_init(&fs_devices->device_list_mutex);
 485         fs_devices->latest_devid = orig->latest_devid;
 486         fs_devices->latest_trans = orig->latest_trans;
 487         fs_devices->total_devices = orig->total_devices;
 488         memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
 489
 490         /* We have held the volume lock, it is safe to get the devices. */
 491         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
 492                 struct rcu_string *name;
 493
 494                 device = kzalloc(sizeof(*device), GFP_NOFS);
 495                 if (!device)
 496                         goto error;
 497
 498                 /*
 499                  * This is ok to do without rcu read locked because we hold the
 500                  * uuid mutex so nothing we touch in here is going to disappear.
 501                  */
 502                 name = rcu_string_strdup(orig_dev->name->str, GFP_NOFS);
 503                 if (!name) {
 504                         kfree(device);
 505                         goto error;
 506                 }
 507                 rcu_assign_pointer(device->name, name);
 508
 509                 device->devid = orig_dev->devid;
 510                 device->work.func = pending_bios_fn;
 511                 memcpy(device->uuid, orig_dev->uuid, sizeof(device->uuid));
 512                 spin_lock_init(&device->io_lock);
 513                 INIT_LIST_HEAD(&device->dev_list);
 514                 INIT_LIST_HEAD(&device->dev_alloc_list);
 515
 516                 list_add(&device->dev_list, &fs_devices->devices);
 517                 device->fs_devices = fs_devices;
 518                 fs_devices->num_devices++;
 519         }
 520         return fs_devices;
 521 error:
 522         free_fs_devices(fs_devices);
 523         return ERR_PTR(-ENOMEM);
 524 }
 525
 526 void btrfs_close_extra_devices(struct btrfs_fs_info *fs_info,
 527                                struct btrfs_fs_devices *fs_devices, int step)
 528 {
 529         struct btrfs_device *device, *next;
 530
 531         struct block_device *latest_bdev = NULL;
 532         u64 latest_devid = 0;
 533         u64 latest_transid = 0;
 534
 535         mutex_lock(&uuid_mutex);
 536 again:
 537         /* This is the initialized path, it is safe to release the devices. */
 538         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
 539                 if (device->in_fs_metadata) {
 540                         if (!device->is_tgtdev_for_dev_replace &&
 541                             (!latest_transid ||
 542                              device->generation > latest_transid)) {
 543                                 latest_devid = device->devid;
 544                                 latest_transid = device->generation;
 545                                 latest_bdev = device->bdev;
 546                         }
 547                         continue;
 548                 }
 549
 550                 if (device->devid == BTRFS_DEV_REPLACE_DEVID) {
 551                         /*
 552                          * In the first step, keep the device which has
 553                          * the correct fsid and the devid that is used
 554                          * for the dev_replace procedure.
 555                          * In the second step, the dev_replace state is
 556                          * read from the device tree and it is known
 557                          * whether the procedure is really active or
 558                          * not, which means whether this device is
 559                          * used or whether it should be removed.
 560                          */
 561                         if (step == 0 || device->is_tgtdev_for_dev_replace) {
 562                                 continue;
 563                         }
 564                 }
 565                 if (device->bdev) {
 566                         blkdev_put(device->bdev, device->mode);
 567                         device->bdev = NULL;
 568                         fs_devices->open_devices--;
 569                 }
 570                 if (device->writeable) {
 571                         list_del_init(&device->dev_alloc_list);
 572                         device->writeable = 0;
 573                         if (!device->is_tgtdev_for_dev_replace)
 574                                 fs_devices->rw_devices--;
 575                 }
 576                 list_del_init(&device->dev_list);
 577                 fs_devices->num_devices--;
 578                 rcu_string_free(device->name);
 579                 kfree(device);
 580         }
 581
 582         if (fs_devices->seed) {
 583                 fs_devices = fs_devices->seed;
 584                 goto again;
 585         }
 586
 587         fs_devices->latest_bdev = latest_bdev;
 588         fs_devices->latest_devid = latest_devid;
 589         fs_devices->latest_trans = latest_transid;
 590
 591         mutex_unlock(&uuid_mutex);
 592 }
 593
 594 static void __free_device(struct work_struct *work)
 595 {
 596         struct btrfs_device *device;
 597
 598         device = container_of(work, struct btrfs_device, rcu_work);
 599
 600         if (device->bdev)
 601                 blkdev_put(device->bdev, device->mode);
 602
 603         rcu_string_free(device->name);
 604         kfree(device);
 605 }
 606
 607 static void free_device(struct rcu_head *head)
 608 {
 609         struct btrfs_device *device;
 610
 611         device = container_of(head, struct btrfs_device, rcu);
 612
 613         INIT_WORK(&device->rcu_work, __free_device);
 614         schedule_work(&device->rcu_work);
 615 }
 616
 617 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 618 {
 619         struct btrfs_device *device;
 620
 621         if (--fs_devices->opened > 0)
 622                 return 0;
 623
 624         mutex_lock(&fs_devices->device_list_mutex);
 625         list_for_each_entry(device, &fs_devices->devices, dev_list) {
 626                 struct btrfs_device *new_device;
 627                 struct rcu_string *name;
 628
 629                 if (device->bdev)
 630                         fs_devices->open_devices--;
 631
 632                 if (device->writeable && !device->is_tgtdev_for_dev_replace) {
 633                         list_del_init(&device->dev_alloc_list);
 634                         fs_devices->rw_devices--;
 635                 }
 636
 637                 if (device->can_discard)
 638                         fs_devices->num_can_discard--;
 639
 640                 new_device = kmalloc(sizeof(*new_device), GFP_NOFS);
 641                 BUG_ON(!new_device); /* -ENOMEM */
 642                 memcpy(new_device, device, sizeof(*new_device));
 643
 644                 /* Safe because we are under uuid_mutex */
 645                 if (device->name) {
 646                         name = rcu_string_strdup(device->name->str, GFP_NOFS);
 647                         BUG_ON(device->name && !name); /* -ENOMEM */
 648                         rcu_assign_pointer(new_device->name, name);
 649                 }
 650                 new_device->bdev = NULL;
 651                 new_device->writeable = 0;
 652                 new_device->in_fs_metadata = 0;
 653                 new_device->can_discard = 0;
 654                 spin_lock_init(&new_device->io_lock);
 655                 list_replace_rcu(&device->dev_list, &new_device->dev_list);
 656
 657                 call_rcu(&device->rcu, free_device);
 658         }
 659         mutex_unlock(&fs_devices->device_list_mutex);
 660
 661         WARN_ON(fs_devices->open_devices);
 662         WARN_ON(fs_devices->rw_devices);
 663         fs_devices->opened = 0;
 664         fs_devices->seeding = 0;
 665
 666         return 0;
 667 }
 668
 669 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 670 {
 671         struct btrfs_fs_devices *seed_devices = NULL;
 672         int ret;
 673
 674         mutex_lock(&uuid_mutex);
 675         ret = __btrfs_close_devices(fs_devices);
 676         if (!fs_devices->opened) {
 677                 seed_devices = fs_devices->seed;
 678                 fs_devices->seed = NULL;
 679         }
 680         mutex_unlock(&uuid_mutex);
 681
 682         while (seed_devices) {
 683                 fs_devices = seed_devices;
 684                 seed_devices = fs_devices->seed;
 685                 __btrfs_close_devices(fs_devices);
 686                 free_fs_devices(fs_devices);
 687         }
 688         /*
 689          * Wait for rcu kworkers under __btrfs_close_devices
 690          * to finish all blkdev_puts so device is really
 691          * free when umount is done.
 692          */
 693         rcu_barrier();
 694         return ret;
 695 }
 696
 697 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 698                                 fmode_t flags, void *holder)
 699 {
 700         struct request_queue *q;
 701         struct block_device *bdev;
 702         struct list_head *head = &fs_devices->devices;
 703         struct btrfs_device *device;
 704         struct block_device *latest_bdev = NULL;
 705         struct buffer_head *bh;
 706         struct btrfs_super_block *disk_super;
 707         u64 latest_devid = 0;
 708         u64 latest_transid = 0;
 709         u64 devid;
 710         int seeding = 1;
 711         int ret = 0;
 712
 713         flags |= FMODE_EXCL;
 714
 715         list_for_each_entry(device, head, dev_list) {
 716                 if (device->bdev)
 717                         continue;
 718                 if (!device->name)
 719                         continue;
 720
 721                 /* Just open everything we can; ignore failures here */
 722                 if (btrfs_get_bdev_and_sb(device->name->str, flags, holder, 1,
 723                                             &bdev, &bh))
 724                         continue;
 725
 726                 disk_super = (struct btrfs_super_block *)bh->b_data;
 727                 devid = btrfs_stack_device_id(&disk_super->dev_item);
 728                 if (devid != device->devid)
 729                         goto error_brelse;
 730
 731                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
 732                            BTRFS_UUID_SIZE))
 733                         goto error_brelse;
 734
 735                 device->generation = btrfs_super_generation(disk_super);
 736                 if (!latest_transid || device->generation > latest_transid) {
 737                         latest_devid = devid;
 738                         latest_transid = device->generation;
 739                         latest_bdev = bdev;
 740                 }
 741
 742                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
 743                         device->writeable = 0;
 744                 } else {
 745                         device->writeable = !bdev_read_only(bdev);
 746                         seeding = 0;
 747                 }
 748
 749                 q = bdev_get_queue(bdev);
 750                 if (blk_queue_discard(q)) {
 751                         device->can_discard = 1;
 752                         fs_devices->num_can_discard++;
 753                 }
 754
 755                 device->bdev = bdev;
 756                 device->in_fs_metadata = 0;
 757                 device->mode = flags;
 758
 759                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
 760                         fs_devices->rotating = 1;
 761
 762                 fs_devices->open_devices++;
 763                 if (device->writeable && !device->is_tgtdev_for_dev_replace) {
 764                         fs_devices->rw_devices++;
 765                         list_add(&device->dev_alloc_list,
 766                                  &fs_devices->alloc_list);
 767                 }
 768                 brelse(bh);
 769                 continue;
 770
 771 error_brelse:
 772                 brelse(bh);
 773                 blkdev_put(bdev, flags);
 774                 continue;
 775         }
 776         if (fs_devices->open_devices == 0) {
 777                 ret = -EINVAL;
 778                 goto out;
 779         }
 780         fs_devices->seeding = seeding;
 781         fs_devices->opened = 1;
 782         fs_devices->latest_bdev = latest_bdev;
 783         fs_devices->latest_devid = latest_devid;
 784         fs_devices->latest_trans = latest_transid;
 785         fs_devices->total_rw_bytes = 0;
 786 out:
 787         return ret;
 788 }
 789
 790 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 791                        fmode_t flags, void *holder)
 792 {
 793         int ret;
 794
 795         mutex_lock(&uuid_mutex);
 796         if (fs_devices->opened) {
 797                 fs_devices->opened++;
 798                 ret = 0;
 799         } else {
 800                 ret = __btrfs_open_devices(fs_devices, flags, holder);
 801         }
 802         mutex_unlock(&uuid_mutex);
 803         return ret;
 804 }
 805
 806 /*
 807  * Look for a btrfs signature on a device. This may be called out of the mount path
 808  * and we are not allowed to call set_blocksize during the scan. The superblock
 809  * is read via pagecache
 810  */
 811 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 812                           struct btrfs_fs_devices **fs_devices_ret)
 813 {
 814         struct btrfs_super_block *disk_super;
 815         struct block_device *bdev;
 816         struct page *page;
 817         void *p;
 818         int ret = -EINVAL;
 819         u64 devid;
 820         u64 transid;
 821         u64 total_devices;
 822         u64 bytenr;
 823         pgoff_t index;
 824
 825         /*
 826          * we would like to check all the supers, but that would make
 827          * a btrfs mount succeed after a mkfs from a different FS.
 828          * So, we need to add a special mount option to scan for
 829          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
 830          */
 831         bytenr = btrfs_sb_offset(0);
 832         flags |= FMODE_EXCL;
 833         mutex_lock(&uuid_mutex);
 834
 835         bdev = blkdev_get_by_path(path, flags, holder);
 836
 837         if (IS_ERR(bdev)) {
 838                 ret = PTR_ERR(bdev);
 839                 goto error;
 840         }
 841
 842         /* make sure our super fits in the device */
 843         if (bytenr + PAGE_CACHE_SIZE >= i_size_read(bdev->bd_inode))
 844                 goto error_bdev_put;
 845
 846         /* make sure our super fits in the page */
 847         if (sizeof(*disk_super) > PAGE_CACHE_SIZE)
 848                 goto error_bdev_put;
 849
 850         /* make sure our super doesn't straddle pages on disk */
 851         index = bytenr >> PAGE_CACHE_SHIFT;
 852         if ((bytenr + sizeof(*disk_super) - 1) >> PAGE_CACHE_SHIFT != index)
 853                 goto error_bdev_put;
 854
 855         /* pull in the page with our super */
 856         page = read_cache_page_gfp(bdev->bd_inode->i_mapping,
 857                                    index, GFP_NOFS);
 858
 859         if (IS_ERR_OR_NULL(page))
 860                 goto error_bdev_put;
 861
 862         p = kmap(page);
 863
 864         /* align our pointer to the offset of the super block */
 865         disk_super = p + (bytenr & ~PAGE_CACHE_MASK);
 866
 867         if (btrfs_super_bytenr(disk_super) != bytenr ||
 868             disk_super->magic != cpu_to_le64(BTRFS_MAGIC))
 869                 goto error_unmap;
 870
 871         devid = btrfs_stack_device_id(&disk_super->dev_item);
 872         transid = btrfs_super_generation(disk_super);
 873         total_devices = btrfs_super_num_devices(disk_super);
 874
 875         if (disk_super->label[0]) {
 876                 if (disk_super->label[BTRFS_LABEL_SIZE - 1])
 877                         disk_super->label[BTRFS_LABEL_SIZE - 1] = '\0';
 878                 printk(KERN_INFO "device label %s ", disk_super->label);
 879         } else {
 880                 printk(KERN_INFO "device fsid %pU ", disk_super->fsid);
 881         }
 882
 883         printk(KERN_CONT "devid %llu transid %llu %s\n",
 884                (unsigned long long)devid, (unsigned long long)transid, path);
 885
 886         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
 887         if (!ret && fs_devices_ret)
 888                 (*fs_devices_ret)->total_devices = total_devices;
 889
 890 error_unmap:
 891         kunmap(page);
 892         page_cache_release(page);
 893
 894 error_bdev_put:
 895         blkdev_put(bdev, flags);
 896 error:
 897         mutex_unlock(&uuid_mutex);
 898         return ret;
 899 }
 900
 901 /* helper to account the used device space in the range */
 902 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
 903                                    u64 end, u64 *length)
 904 {
 905         struct btrfs_key key;
 906         struct btrfs_root *root = device->dev_root;
 907         struct btrfs_dev_extent *dev_extent;
 908         struct btrfs_path *path;
 909         u64 extent_end;
 910         int ret;
 911         int slot;
 912         struct extent_buffer *l;
 913
 914         *length = 0;
 915
 916         if (start >= device->total_bytes || device->is_tgtdev_for_dev_replace)
 917                 return 0;
 918
 919         path = btrfs_alloc_path();
 920         if (!path)
 921                 return -ENOMEM;
 922         path->reada = 2;
 923
 924         key.objectid = device->devid;
 925         key.offset = start;
 926         key.type = BTRFS_DEV_EXTENT_KEY;
 927
 928         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 929         if (ret < 0)
 930                 goto out;
 931         if (ret > 0) {
 932                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
 933                 if (ret < 0)
 934                         goto out;
 935         }
 936
 937         while (1) {
 938                 l = path->nodes[0];
 939                 slot = path->slots[0];
 940                 if (slot >= btrfs_header_nritems(l)) {
 941                         ret = btrfs_next_leaf(root, path);
 942                         if (ret == 0)
 943                                 continue;
 944                         if (ret < 0)
 945                                 goto out;
 946
 947                         break;
 948                 }
 949                 btrfs_item_key_to_cpu(l, &key, slot);
 950
 951                 if (key.objectid < device->devid)
 952                         goto next;
 953
 954                 if (key.objectid > device->devid)
 955                         break;
 956
 957                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
 958                         goto next;
 959
 960                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
 961                 extent_end = key.offset + btrfs_dev_extent_length(l,
 962                                                                   dev_extent);
 963                 if (key.offset <= start && extent_end > end) {
 964                         *length = end - start + 1;
 965                         break;
 966                 } else if (key.offset <= start && extent_end > start)
 967                         *length += extent_end - start;
 968                 else if (key.offset > start && extent_end <= end)
 969                         *length += extent_end - key.offset;
 970                 else if (key.offset > start && key.offset <= end) {
 971                         *length += end - key.offset + 1;
 972                         break;
 973                 } else if (key.offset > end)
 974                         break;
 975
 976 next:
 977                 path->slots[0]++;
 978         }
 979         ret = 0;
 980 out:
 981         btrfs_free_path(path);
 982         return ret;
 983 }
 984
 985 /*
 986  * find_free_dev_extent - find free space in the specified device
 987  * @device:     the device which we search the free space in
 988  * @num_bytes:  the size of the free space that we need
 989  * @start:      store the start of the free space.
 990  * @len:        the size of the free space. that we find, or the size of the max
 991  *              free space if we don't find suitable free space
 992  *
 993  * this uses a pretty simple search, the expectation is that it is
 994  * called very infrequently and that a given device has a small number
 995  * of extents
 996  *
 997  * @start is used to store the start of the free space if we find. But if we
 998  * don't find suitable free space, it will be used to store the start position
 999  * of the max free space.
1000  *
1001  * @len is used to store the size of the free space that we find.
1002  * But if we don't find suitable free space, it is used to store the size of
1003  * the max free space.
1004  */
1005 int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
1006                          u64 *start, u64 *len)
1007 {
1008         struct btrfs_key key;
1009         struct btrfs_root *root = device->dev_root;
1010         struct btrfs_dev_extent *dev_extent;
1011         struct btrfs_path *path;
1012         u64 hole_size;
1013         u64 max_hole_start;
1014         u64 max_hole_size;
1015         u64 extent_end;
1016         u64 search_start;
1017         u64 search_end = device->total_bytes;
1018         int ret;
1019         int slot;
1020         struct extent_buffer *l;
1021
1022         /* FIXME use last free of some kind */
1023
1024         /* we don't want to overwrite the superblock on the drive,
1025          * so we make sure to start at an offset of at least 1MB
1026          */
1027         search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
1028
1029         max_hole_start = search_start;
1030         max_hole_size = 0;
1031         hole_size = 0;
1032
1033         if (search_start >= search_end || device->is_tgtdev_for_dev_replace) {
1034                 ret = -ENOSPC;
1035                 goto error;
1036         }
1037
1038         path = btrfs_alloc_path();
1039         if (!path) {
1040                 ret = -ENOMEM;
1041                 goto error;
1042         }
1043         path->reada = 2;
1044
1045         key.objectid = device->devid;
1046         key.offset = search_start;
1047         key.type = BTRFS_DEV_EXTENT_KEY;
1048
1049         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1050         if (ret < 0)
1051                 goto out;
1052         if (ret > 0) {
1053                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
1054                 if (ret < 0)
1055                         goto out;
1056         }
1057
1058         while (1) {
1059                 l = path->nodes[0];
1060                 slot = path->slots[0];
1061                 if (slot >= btrfs_header_nritems(l)) {
1062                         ret = btrfs_next_leaf(root, path);
1063                         if (ret == 0)
1064                                 continue;
1065                         if (ret < 0)
1066                                 goto out;
1067
1068                         break;
1069                 }
1070                 btrfs_item_key_to_cpu(l, &key, slot);
1071
1072                 if (key.objectid < device->devid)
1073                         goto next;
1074
1075                 if (key.objectid > device->devid)
1076                         break;
1077
1078                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
1079                         goto next;
1080
1081                 if (key.offset > search_start) {
1082                         hole_size = key.offset - search_start;
1083
1084                         if (hole_size > max_hole_size) {
1085                                 max_hole_start = search_start;
1086                                 max_hole_size = hole_size;
1087                         }
1088
1089                         /*
1090                          * If this free space is greater than which we need,
1091                          * it must be the max free space that we have found
1092                          * until now, so max_hole_start must point to the start
1093                          * of this free space and the length of this free space
1094                          * is stored in max_hole_size. Thus, we return
1095                          * max_hole_start and max_hole_size and go back to the
1096                          * caller.
1097                          */
1098                         if (hole_size >= num_bytes) {
1099                                 ret = 0;
1100                                 goto out;
1101                         }
1102                 }
1103
1104                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1105                 extent_end = key.offset + btrfs_dev_extent_length(l,
1106                                                                   dev_extent);
1107                 if (extent_end > search_start)
1108                         search_start = extent_end;
1109 next:
1110                 path->slots[0]++;
1111                 cond_resched();
1112         }
1113
1114         /*
1115          * At this point, search_start should be the end of
1116          * allocated dev extents, and when shrinking the device,
1117          * search_end may be smaller than search_start.
1118          */
1119         if (search_end > search_start)
1120                 hole_size = search_end - search_start;
1121
1122         if (hole_size > max_hole_size) {
1123                 max_hole_start = search_start;
1124                 max_hole_size = hole_size;
1125         }
1126
1127         /* See above. */
1128         if (hole_size < num_bytes)
1129                 ret = -ENOSPC;
1130         else
1131                 ret = 0;
1132
1133 out:
1134         btrfs_free_path(path);
1135 error:
1136         *start = max_hole_start;
1137         if (len)
1138                 *len = max_hole_size;
1139         return ret;
1140 }
1141
1142 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
1143                           struct btrfs_device *device,
1144                           u64 start)
1145 {
1146         int ret;
1147         struct btrfs_path *path;
1148         struct btrfs_root *root = device->dev_root;
1149         struct btrfs_key key;
1150         struct btrfs_key found_key;
1151         struct extent_buffer *leaf = NULL;
1152         struct btrfs_dev_extent *extent = NULL;
1153
1154         path = btrfs_alloc_path();
1155         if (!path)
1156                 return -ENOMEM;
1157
1158         key.objectid = device->devid;
1159         key.offset = start;
1160         key.type = BTRFS_DEV_EXTENT_KEY;
1161 again:
1162         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1163         if (ret > 0) {
1164                 ret = btrfs_previous_item(root, path, key.objectid,
1165                                           BTRFS_DEV_EXTENT_KEY);
1166                 if (ret)
1167                         goto out;
1168                 leaf = path->nodes[0];
1169                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1170                 extent = btrfs_item_ptr(leaf, path->slots[0],
1171                                         struct btrfs_dev_extent);
1172                 BUG_ON(found_key.offset > start || found_key.offset +
1173                        btrfs_dev_extent_length(leaf, extent) < start);
1174                 key = found_key;
1175                 btrfs_release_path(path);
1176                 goto again;
1177         } else if (ret == 0) {
1178                 leaf = path->nodes[0];
1179                 extent = btrfs_item_ptr(leaf, path->slots[0],
1180                                         struct btrfs_dev_extent);
1181         } else {
1182                 btrfs_error(root->fs_info, ret, "Slot search failed");
1183                 goto out;
1184         }
1185
1186         if (device->bytes_used > 0) {
1187                 u64 len = btrfs_dev_extent_length(leaf, extent);
1188                 device->bytes_used -= len;
1189                 spin_lock(&root->fs_info->free_chunk_lock);
1190                 root->fs_info->free_chunk_space += len;
1191                 spin_unlock(&root->fs_info->free_chunk_lock);
1192         }
1193         ret = btrfs_del_item(trans, root, path);
1194         if (ret) {
1195                 btrfs_error(root->fs_info, ret,
1196                             "Failed to remove dev extent item");
1197         }
1198 out:
1199         btrfs_free_path(path);
1200         return ret;
1201 }
1202
1203 static int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
1204                                   struct btrfs_device *device,
1205                                   u64 chunk_tree, u64 chunk_objectid,
1206                                   u64 chunk_offset, u64 start, u64 num_bytes)
1207 {
1208         int ret;
1209         struct btrfs_path *path;
1210         struct btrfs_root *root = device->dev_root;
1211         struct btrfs_dev_extent *extent;
1212         struct extent_buffer *leaf;
1213         struct btrfs_key key;
1214
1215         WARN_ON(!device->in_fs_metadata);
1216         WARN_ON(device->is_tgtdev_for_dev_replace);
1217         path = btrfs_alloc_path();
1218         if (!path)
1219                 return -ENOMEM;
1220
1221         key.objectid = device->devid;
1222         key.offset = start;
1223         key.type = BTRFS_DEV_EXTENT_KEY;
1224         ret = btrfs_insert_empty_item(trans, root, path, &key,
1225                                       sizeof(*extent));
1226         if (ret)
1227                 goto out;
1228
1229         leaf = path->nodes[0];
1230         extent = btrfs_item_ptr(leaf, path->slots[0],
1231                                 struct btrfs_dev_extent);
1232         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
1233         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
1234         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1235
1236         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
1237                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
1238                     BTRFS_UUID_SIZE);
1239
1240         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1241         btrfs_mark_buffer_dirty(leaf);
1242 out:
1243         btrfs_free_path(path);
1244         return ret;
1245 }
1246
1247 static noinline int find_next_chunk(struct btrfs_root *root,
1248                                     u64 objectid, u64 *offset)
1249 {
1250         struct btrfs_path *path;
1251         int ret;
1252         struct btrfs_key key;
1253         struct btrfs_chunk *chunk;
1254         struct btrfs_key found_key;
1255
1256         path = btrfs_alloc_path();
1257         if (!path)
1258                 return -ENOMEM;
1259
1260         key.objectid = objectid;
1261         key.offset = (u64)-1;
1262         key.type = BTRFS_CHUNK_ITEM_KEY;
1263
1264         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1265         if (ret < 0)
1266                 goto error;
1267
1268         BUG_ON(ret == 0); /* Corruption */
1269
1270         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
1271         if (ret) {
1272                 *offset = 0;
1273         } else {
1274                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1275                                       path->slots[0]);
1276                 if (found_key.objectid != objectid)
1277                         *offset = 0;
1278                 else {
1279                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
1280                                                struct btrfs_chunk);
1281                         *offset = found_key.offset +
1282                                 btrfs_chunk_length(path->nodes[0], chunk);
1283                 }
1284         }
1285         ret = 0;
1286 error:
1287         btrfs_free_path(path);
1288         return ret;
1289 }
1290
1291 static noinline int find_next_devid(struct btrfs_root *root, u64 *objectid)
1292 {
1293         int ret;
1294         struct btrfs_key key;
1295         struct btrfs_key found_key;
1296         struct btrfs_path *path;
1297
1298         root = root->fs_info->chunk_root;
1299
1300         path = btrfs_alloc_path();
1301         if (!path)
1302                 return -ENOMEM;
1303
1304         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1305         key.type = BTRFS_DEV_ITEM_KEY;
1306         key.offset = (u64)-1;
1307
1308         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1309         if (ret < 0)
1310                 goto error;
1311
1312         BUG_ON(ret == 0); /* Corruption */
1313
1314         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
1315                                   BTRFS_DEV_ITEM_KEY);
1316         if (ret) {
1317                 *objectid = 1;
1318         } else {
1319                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1320                                       path->slots[0]);
1321                 *objectid = found_key.offset + 1;
1322         }
1323         ret = 0;
1324 error:
1325         btrfs_free_path(path);
1326         return ret;
1327 }
1328
1329 /*
1330  * the device information is stored in the chunk root
1331  * the btrfs_device struct should be fully filled in
1332  */
1333 static int btrfs_add_device(struct btrfs_trans_handle *trans,
1334                             struct btrfs_root *root,
1335                             struct btrfs_device *device)
1336 {
1337         int ret;
1338         struct btrfs_path *path;
1339         struct btrfs_dev_item *dev_item;
1340         struct extent_buffer *leaf;
1341         struct btrfs_key key;
1342         unsigned long ptr;
1343
1344         root = root->fs_info->chunk_root;
1345
1346         path = btrfs_alloc_path();
1347         if (!path)
1348                 return -ENOMEM;
1349
1350         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1351         key.type = BTRFS_DEV_ITEM_KEY;
1352         key.offset = device->devid;
1353
1354         ret = btrfs_insert_empty_item(trans, root, path, &key,
1355                                       sizeof(*dev_item));
1356         if (ret)
1357                 goto out;
1358
1359         leaf = path->nodes[0];
1360         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1361
1362         btrfs_set_device_id(leaf, dev_item, device->devid);
1363         btrfs_set_device_generation(leaf, dev_item, 0);
1364         btrfs_set_device_type(leaf, dev_item, device->type);
1365         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1366         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1367         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1368         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1369         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1370         btrfs_set_device_group(leaf, dev_item, 0);
1371         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1372         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1373         btrfs_set_device_start_offset(leaf, dev_item, 0);
1374
1375         ptr = (unsigned long)btrfs_device_uuid(dev_item);
1376         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1377         ptr = (unsigned long)btrfs_device_fsid(dev_item);
1378         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1379         btrfs_mark_buffer_dirty(leaf);
1380
1381         ret = 0;
1382 out:
1383         btrfs_free_path(path);
1384         return ret;
1385 }
1386
1387 static int btrfs_rm_dev_item(struct btrfs_root *root,
1388                              struct btrfs_device *device)
1389 {
1390         int ret;
1391         struct btrfs_path *path;
1392         struct btrfs_key key;
1393         struct btrfs_trans_handle *trans;
1394
1395         root = root->fs_info->chunk_root;
1396
1397         path = btrfs_alloc_path();
1398         if (!path)
1399                 return -ENOMEM;
1400
1401         trans = btrfs_start_transaction(root, 0);
1402         if (IS_ERR(trans)) {
1403                 btrfs_free_path(path);
1404                 return PTR_ERR(trans);
1405         }
1406         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1407         key.type = BTRFS_DEV_ITEM_KEY;
1408         key.offset = device->devid;
1409         lock_chunks(root);
1410
1411         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1412         if (ret < 0)
1413                 goto out;
1414
1415         if (ret > 0) {
1416                 ret = -ENOENT;
1417                 goto out;
1418         }
1419
1420         ret = btrfs_del_item(trans, root, path);
1421         if (ret)
1422                 goto out;
1423 out:
1424         btrfs_free_path(path);
1425         unlock_chunks(root);
1426         btrfs_commit_transaction(trans, root);
1427         return ret;
1428 }
1429
1430 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1431 {
1432         struct btrfs_device *device;
1433         struct btrfs_device *next_device;
1434         struct block_device *bdev;
1435         struct buffer_head *bh = NULL;
1436         struct btrfs_super_block *disk_super;
1437         struct btrfs_fs_devices *cur_devices;
1438         u64 all_avail;
1439         u64 devid;
1440         u64 num_devices;
1441         u8 *dev_uuid;
1442         unsigned seq;
1443         int ret = 0;
1444         bool clear_super = false;
1445
1446         mutex_lock(&uuid_mutex);
1447
1448         do {
1449                 seq = read_seqbegin(&root->fs_info->profiles_lock);
1450
1451                 all_avail = root->fs_info->avail_data_alloc_bits |
1452                             root->fs_info->avail_system_alloc_bits |
1453                             root->fs_info->avail_metadata_alloc_bits;
1454         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
1455
1456         num_devices = root->fs_info->fs_devices->num_devices;
1457         btrfs_dev_replace_lock(&root->fs_info->dev_replace);
1458         if (btrfs_dev_replace_is_ongoing(&root->fs_info->dev_replace)) {
1459                 WARN_ON(num_devices < 1);
1460                 num_devices--;
1461         }
1462         btrfs_dev_replace_unlock(&root->fs_info->dev_replace);
1463
1464         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) && num_devices <= 4) {
1465                 printk(KERN_ERR "btrfs: unable to go below four devices "
1466                        "on raid10\n");
1467                 ret = -EINVAL;
1468                 goto out;
1469         }
1470
1471         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) && num_devices <= 2) {
1472                 printk(KERN_ERR "btrfs: unable to go below two "
1473                        "devices on raid1\n");
1474                 ret = -EINVAL;
1475                 goto out;
1476         }
1477
1478         if ((all_avail & BTRFS_BLOCK_GROUP_RAID5) &&
1479             root->fs_info->fs_devices->rw_devices <= 2) {
1480                 printk(KERN_ERR "btrfs: unable to go below two "
1481                        "devices on raid5\n");
1482                 ret = -EINVAL;
1483                 goto out;
1484         }
1485         if ((all_avail & BTRFS_BLOCK_GROUP_RAID6) &&
1486             root->fs_info->fs_devices->rw_devices <= 3) {
1487                 printk(KERN_ERR "btrfs: unable to go below three "
1488                        "devices on raid6\n");
1489                 ret = -EINVAL;
1490                 goto out;
1491         }
1492
1493         if (strcmp(device_path, "missing") == 0) {
1494                 struct list_head *devices;
1495                 struct btrfs_device *tmp;
1496
1497                 device = NULL;
1498                 devices = &root->fs_info->fs_devices->devices;
1499                 /*
1500                  * It is safe to read the devices since the volume_mutex
1501                  * is held.
1502                  */
1503                 list_for_each_entry(tmp, devices, dev_list) {
1504                         if (tmp->in_fs_metadata &&
1505                             !tmp->is_tgtdev_for_dev_replace &&
1506                             !tmp->bdev) {
1507                                 device = tmp;
1508                                 break;
1509                         }
1510                 }
1511                 bdev = NULL;
1512                 bh = NULL;
1513                 disk_super = NULL;
1514                 if (!device) {
1515                         printk(KERN_ERR "btrfs: no missing devices found to "
1516                                "remove\n");
1517                         goto out;
1518                 }
1519         } else {
1520                 ret = btrfs_get_bdev_and_sb(device_path,
1521                                             FMODE_WRITE | FMODE_EXCL,
1522                                             root->fs_info->bdev_holder, 0,
1523                                             &bdev, &bh);
1524                 if (ret)
1525                         goto out;
1526                 disk_super = (struct btrfs_super_block *)bh->b_data;
1527                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1528                 dev_uuid = disk_super->dev_item.uuid;
1529                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1530                                            disk_super->fsid);
1531                 if (!device) {
1532                         ret = -ENOENT;
1533                         goto error_brelse;
1534                 }
1535         }
1536
1537         if (device->is_tgtdev_for_dev_replace) {
1538                 pr_err("btrfs: unable to remove the dev_replace target dev\n");
1539                 ret = -EINVAL;
1540                 goto error_brelse;
1541         }
1542
1543         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1544                 printk(KERN_ERR "btrfs: unable to remove the only writeable "
1545                        "device\n");
1546                 ret = -EINVAL;
1547                 goto error_brelse;
1548         }
1549
1550         if (device->writeable) {
1551                 lock_chunks(root);
1552                 list_del_init(&device->dev_alloc_list);
1553                 unlock_chunks(root);
1554                 root->fs_info->fs_devices->rw_devices--;
1555                 clear_super = true;
1556         }
1557
1558         ret = btrfs_shrink_device(device, 0);
1559         if (ret)
1560                 goto error_undo;
1561
1562         /*
1563          * TODO: the superblock still includes this device in its num_devices
1564          * counter although write_all_supers() is not locked out. This
1565          * could give a filesystem state which requires a degraded mount.
1566          */
1567         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1568         if (ret)
1569                 goto error_undo;
1570
1571         spin_lock(&root->fs_info->free_chunk_lock);
1572         root->fs_info->free_chunk_space = device->total_bytes -
1573                 device->bytes_used;
1574         spin_unlock(&root->fs_info->free_chunk_lock);
1575
1576         device->in_fs_metadata = 0;
1577         btrfs_scrub_cancel_dev(root->fs_info, device);
1578
1579         /*
1580          * the device list mutex makes sure that we don't change
1581          * the device list while someone else is writing out all
1582          * the device supers.
1583          */
1584
1585         cur_devices = device->fs_devices;
1586         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1587         list_del_rcu(&device->dev_list);
1588
1589         device->fs_devices->num_devices--;
1590         device->fs_devices->total_devices--;
1591
1592         if (device->missing)
1593                 root->fs_info->fs_devices->missing_devices--;
1594
1595         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1596                                  struct btrfs_device, dev_list);
1597         if (device->bdev == root->fs_info->sb->s_bdev)
1598                 root->fs_info->sb->s_bdev = next_device->bdev;
1599         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1600                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1601
1602         if (device->bdev)
1603                 device->fs_devices->open_devices--;
1604
1605         call_rcu(&device->rcu, free_device);
1606         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1607
1608         num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
1609         btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
1610
1611         if (cur_devices->open_devices == 0) {
1612                 struct btrfs_fs_devices *fs_devices;
1613                 fs_devices = root->fs_info->fs_devices;
1614                 while (fs_devices) {
1615                         if (fs_devices->seed == cur_devices)
1616                                 break;
1617                         fs_devices = fs_devices->seed;
1618                 }
1619                 fs_devices->seed = cur_devices->seed;
1620                 cur_devices->seed = NULL;
1621                 lock_chunks(root);
1622                 __btrfs_close_devices(cur_devices);
1623                 unlock_chunks(root);
1624                 free_fs_devices(cur_devices);
1625         }
1626
1627         root->fs_info->num_tolerated_disk_barrier_failures =
1628                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1629
1630         /*
1631          * at this point, the device is zero sized.  We want to
1632          * remove it from the devices list and zero out the old super
1633          */
1634         if (clear_super && disk_super) {
1635                 /* make sure this device isn't detected as part of
1636                  * the FS anymore
1637                  */
1638                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1639                 set_buffer_dirty(bh);
1640                 sync_dirty_buffer(bh);
1641         }
1642
1643         ret = 0;
1644
1645         /* Notify udev that device has changed */
1646         if (bdev)
1647                 btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
1648
1649 error_brelse:
1650         brelse(bh);
1651         if (bdev)
1652                 blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
1653 out:
1654         mutex_unlock(&uuid_mutex);
1655         return ret;
1656 error_undo:
1657         if (device->writeable) {
1658                 lock_chunks(root);
1659                 list_add(&device->dev_alloc_list,
1660                          &root->fs_info->fs_devices->alloc_list);
1661                 unlock_chunks(root);
1662                 root->fs_info->fs_devices->rw_devices++;
1663         }
1664         goto error_brelse;
1665 }
1666
1667 void btrfs_rm_dev_replace_srcdev(struct btrfs_fs_info *fs_info,
1668                                  struct btrfs_device *srcdev)
1669 {
1670         WARN_ON(!mutex_is_locked(&fs_info->fs_devices->device_list_mutex));
1671         list_del_rcu(&srcdev->dev_list);
1672         list_del_rcu(&srcdev->dev_alloc_list);
1673         fs_info->fs_devices->num_devices--;
1674         if (srcdev->missing) {
1675                 fs_info->fs_devices->missing_devices--;
1676                 fs_info->fs_devices->rw_devices++;
1677         }
1678         if (srcdev->can_discard)
1679                 fs_info->fs_devices->num_can_discard--;
1680         if (srcdev->bdev)
1681                 fs_info->fs_devices->open_devices--;
1682
1683         call_rcu(&srcdev->rcu, free_device);
1684 }
1685
1686 void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
1687                                       struct btrfs_device *tgtdev)
1688 {
1689         struct btrfs_device *next_device;
1690
1691         WARN_ON(!tgtdev);
1692         mutex_lock(&fs_info->fs_devices->device_list_mutex);
1693         if (tgtdev->bdev) {
1694                 btrfs_scratch_superblock(tgtdev);
1695                 fs_info->fs_devices->open_devices--;
1696         }
1697         fs_info->fs_devices->num_devices--;
1698         if (tgtdev->can_discard)
1699                 fs_info->fs_devices->num_can_discard++;
1700
1701         next_device = list_entry(fs_info->fs_devices->devices.next,
1702                                  struct btrfs_device, dev_list);
1703         if (tgtdev->bdev == fs_info->sb->s_bdev)
1704                 fs_info->sb->s_bdev = next_device->bdev;
1705         if (tgtdev->bdev == fs_info->fs_devices->latest_bdev)
1706                 fs_info->fs_devices->latest_bdev = next_device->bdev;
1707         list_del_rcu(&tgtdev->dev_list);
1708
1709         call_rcu(&tgtdev->rcu, free_device);
1710
1711         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1712 }
1713
1714 static int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
1715                                      struct btrfs_device **device)
1716 {
1717         int ret = 0;
1718         struct btrfs_super_block *disk_super;
1719         u64 devid;
1720         u8 *dev_uuid;
1721         struct block_device *bdev;
1722         struct buffer_head *bh;
1723
1724         *device = NULL;
1725         ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ,
1726                                     root->fs_info->bdev_holder, 0, &bdev, &bh);
1727         if (ret)
1728                 return ret;
1729         disk_super = (struct btrfs_super_block *)bh->b_data;
1730         devid = btrfs_stack_device_id(&disk_super->dev_item);
1731         dev_uuid = disk_super->dev_item.uuid;
1732         *device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1733                                     disk_super->fsid);
1734         brelse(bh);
1735         if (!*device)
1736                 ret = -ENOENT;
1737         blkdev_put(bdev, FMODE_READ);
1738         return ret;
1739 }
1740
1741 int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
1742                                          char *device_path,
1743                                          struct btrfs_device **device)
1744 {
1745         *device = NULL;
1746         if (strcmp(device_path, "missing") == 0) {
1747                 struct list_head *devices;
1748                 struct btrfs_device *tmp;
1749
1750                 devices = &root->fs_info->fs_devices->devices;
1751                 /*
1752                  * It is safe to read the devices since the volume_mutex
1753                  * is held by the caller.
1754                  */
1755                 list_for_each_entry(tmp, devices, dev_list) {
1756                         if (tmp->in_fs_metadata && !tmp->bdev) {
1757                                 *device = tmp;
1758                                 break;
1759                         }
1760                 }
1761
1762                 if (!*device) {
1763                         pr_err("btrfs: no missing device found\n");
1764                         return -ENOENT;
1765                 }
1766
1767                 return 0;
1768         } else {
1769                 return btrfs_find_device_by_path(root, device_path, device);
1770         }
1771 }
1772
1773 /*
1774  * does all the dirty work required for changing file system's UUID.
1775  */
1776 static int btrfs_prepare_sprout(struct btrfs_root *root)
1777 {
1778         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
1779         struct btrfs_fs_devices *old_devices;
1780         struct btrfs_fs_devices *seed_devices;
1781         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
1782         struct btrfs_device *device;
1783         u64 super_flags;
1784
1785         BUG_ON(!mutex_is_locked(&uuid_mutex));
1786         if (!fs_devices->seeding)
1787                 return -EINVAL;
1788
1789         seed_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1790         if (!seed_devices)
1791                 return -ENOMEM;
1792
1793         old_devices = clone_fs_devices(fs_devices);
1794         if (IS_ERR(old_devices)) {
1795                 kfree(seed_devices);
1796                 return PTR_ERR(old_devices);
1797         }
1798
1799         list_add(&old_devices->list, &fs_uuids);
1800
1801         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
1802         seed_devices->opened = 1;
1803         INIT_LIST_HEAD(&seed_devices->devices);
1804         INIT_LIST_HEAD(&seed_devices->alloc_list);
1805         mutex_init(&seed_devices->device_list_mutex);
1806
1807         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1808         list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
1809                               synchronize_rcu);
1810         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1811
1812         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
1813         list_for_each_entry(device, &seed_devices->devices, dev_list) {
1814                 device->fs_devices = seed_devices;
1815         }
1816
1817         fs_devices->seeding = 0;
1818         fs_devices->num_devices = 0;
1819         fs_devices->open_devices = 0;
1820         fs_devices->total_devices = 0;
1821         fs_devices->seed = seed_devices;
1822
1823         generate_random_uuid(fs_devices->fsid);
1824         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1825         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1826         super_flags = btrfs_super_flags(disk_super) &
1827                       ~BTRFS_SUPER_FLAG_SEEDING;
1828         btrfs_set_super_flags(disk_super, super_flags);
1829
1830         return 0;
1831 }
1832
1833 /*
1834  * strore the expected generation for seed devices in device items.
1835  */
1836 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
1837                                struct btrfs_root *root)
1838 {
1839         struct btrfs_path *path;
1840         struct extent_buffer *leaf;
1841         struct btrfs_dev_item *dev_item;
1842         struct btrfs_device *device;
1843         struct btrfs_key key;
1844         u8 fs_uuid[BTRFS_UUID_SIZE];
1845         u8 dev_uuid[BTRFS_UUID_SIZE];
1846         u64 devid;
1847         int ret;
1848
1849         path = btrfs_alloc_path();
1850         if (!path)
1851                 return -ENOMEM;
1852
1853         root = root->fs_info->chunk_root;
1854         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1855         key.offset = 0;
1856         key.type = BTRFS_DEV_ITEM_KEY;
1857
1858         while (1) {
1859                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1860                 if (ret < 0)
1861                         goto error;
1862
1863                 leaf = path->nodes[0];
1864 next_slot:
1865                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1866                         ret = btrfs_next_leaf(root, path);
1867                         if (ret > 0)
1868                                 break;
1869                         if (ret < 0)
1870                                 goto error;
1871                         leaf = path->nodes[0];
1872                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1873                         btrfs_release_path(path);
1874                         continue;
1875                 }
1876
1877                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1878                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
1879                     key.type != BTRFS_DEV_ITEM_KEY)
1880                         break;
1881
1882                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
1883                                           struct btrfs_dev_item);
1884                 devid = btrfs_device_id(leaf, dev_item);
1885                 read_extent_buffer(leaf, dev_uuid,
1886                                    (unsigned long)btrfs_device_uuid(dev_item),
1887                                    BTRFS_UUID_SIZE);
1888                 read_extent_buffer(leaf, fs_uuid,
1889                                    (unsigned long)btrfs_device_fsid(dev_item),
1890                                    BTRFS_UUID_SIZE);
1891                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1892                                            fs_uuid);
1893                 BUG_ON(!device); /* Logic error */
1894
1895                 if (device->fs_devices->seeding) {
1896                         btrfs_set_device_generation(leaf, dev_item,
1897                                                     device->generation);
1898                         btrfs_mark_buffer_dirty(leaf);
1899                 }
1900
1901                 path->slots[0]++;
1902                 goto next_slot;
1903         }
1904         ret = 0;
1905 error:
1906         btrfs_free_path(path);
1907         return ret;
1908 }
1909
1910 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
1911 {
1912         struct request_queue *q;
1913         struct btrfs_trans_handle *trans;
1914         struct btrfs_device *device;
1915         struct block_device *bdev;
1916         struct list_head *devices;
1917         struct super_block *sb = root->fs_info->sb;
1918         struct rcu_string *name;
1919         u64 total_bytes;
1920         int seeding_dev = 0;
1921         int ret = 0;
1922
1923         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
1924                 return -EROFS;
1925
1926         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
1927                                   root->fs_info->bdev_holder);
1928         if (IS_ERR(bdev))
1929                 return PTR_ERR(bdev);
1930
1931         if (root->fs_info->fs_devices->seeding) {
1932                 seeding_dev = 1;
1933                 down_write(&sb->s_umount);
1934                 mutex_lock(&uuid_mutex);
1935         }
1936
1937         filemap_write_and_wait(bdev->bd_inode->i_mapping);
1938
1939         devices = &root->fs_info->fs_devices->devices;
1940
1941         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1942         list_for_each_entry(device, devices, dev_list) {
1943                 if (device->bdev == bdev) {
1944                         ret = -EEXIST;
1945                         mutex_unlock(
1946                                 &root->fs_info->fs_devices->device_list_mutex);
1947                         goto error;
1948                 }
1949         }
1950         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1951
1952         device = kzalloc(sizeof(*device), GFP_NOFS);
1953         if (!device) {
1954                 /* we can safely leave the fs_devices entry around */
1955                 ret = -ENOMEM;
1956                 goto error;
1957         }
1958
1959         name = rcu_string_strdup(device_path, GFP_NOFS);
1960         if (!name) {
1961                 kfree(device);
1962                 ret = -ENOMEM;
1963                 goto error;
1964         }
1965         rcu_assign_pointer(device->name, name);
1966
1967         ret = find_next_devid(root, &device->devid);
1968         if (ret) {
1969                 rcu_string_free(device->name);
1970                 kfree(device);
1971                 goto error;
1972         }
1973
1974         trans = btrfs_start_transaction(root, 0);
1975         if (IS_ERR(trans)) {
1976                 rcu_string_free(device->name);
1977                 kfree(device);
1978                 ret = PTR_ERR(trans);
1979                 goto error;
1980         }
1981
1982         lock_chunks(root);
1983
1984         q = bdev_get_queue(bdev);
1985         if (blk_queue_discard(q))
1986                 device->can_discard = 1;
1987         device->writeable = 1;
1988         device->work.func = pending_bios_fn;
1989         generate_random_uuid(device->uuid);
1990         spin_lock_init(&device->io_lock);
1991         device->generation = trans->transid;
1992         device->io_width = root->sectorsize;
1993         device->io_align = root->sectorsize;
1994         device->sector_size = root->sectorsize;
1995         device->total_bytes = i_size_read(bdev->bd_inode);
1996         device->disk_total_bytes = device->total_bytes;
1997         device->dev_root = root->fs_info->dev_root;
1998         device->bdev = bdev;
1999         device->in_fs_metadata = 1;
2000         device->is_tgtdev_for_dev_replace = 0;
2001         device->mode = FMODE_EXCL;
2002         set_blocksize(device->bdev, 4096);
2003
2004         if (seeding_dev) {
2005                 sb->s_flags &= ~MS_RDONLY;
2006                 ret = btrfs_prepare_sprout(root);
2007                 BUG_ON(ret); /* -ENOMEM */
2008         }
2009
2010         device->fs_devices = root->fs_info->fs_devices;
2011
2012         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2013         list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
2014         list_add(&device->dev_alloc_list,
2015                  &root->fs_info->fs_devices->alloc_list);
2016         root->fs_info->fs_devices->num_devices++;
2017         root->fs_info->fs_devices->open_devices++;
2018         root->fs_info->fs_devices->rw_devices++;
2019         root->fs_info->fs_devices->total_devices++;
2020         if (device->can_discard)
2021                 root->fs_info->fs_devices->num_can_discard++;
2022         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
2023
2024         spin_lock(&root->fs_info->free_chunk_lock);
2025         root->fs_info->free_chunk_space += device->total_bytes;
2026         spin_unlock(&root->fs_info->free_chunk_lock);
2027
2028         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
2029                 root->fs_info->fs_devices->rotating = 1;
2030
2031         total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
2032         btrfs_set_super_total_bytes(root->fs_info->super_copy,
2033                                     total_bytes + device->total_bytes);
2034
2035         total_bytes = btrfs_super_num_devices(root->fs_info->super_copy);
2036         btrfs_set_super_num_devices(root->fs_info->super_copy,
2037                                     total_bytes + 1);
2038         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2039
2040         if (seeding_dev) {
2041                 ret = init_first_rw_device(trans, root, device);
2042                 if (ret) {
2043                         btrfs_abort_transaction(trans, root, ret);
2044                         goto error_trans;
2045                 }
2046                 ret = btrfs_finish_sprout(trans, root);
2047                 if (ret) {
2048                         btrfs_abort_transaction(trans, root, ret);
2049                         goto error_trans;
2050                 }
2051         } else {
2052                 ret = btrfs_add_device(trans, root, device);
2053                 if (ret) {
2054                         btrfs_abort_transaction(trans, root, ret);
2055                         goto error_trans;
2056                 }
2057         }
2058
2059         /*
2060          * we've got more storage, clear any full flags on the space
2061          * infos
2062          */
2063         btrfs_clear_space_info_full(root->fs_info);
2064
2065         unlock_chunks(root);
2066         root->fs_info->num_tolerated_disk_barrier_failures =
2067                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
2068         ret = btrfs_commit_transaction(trans, root);
2069
2070         if (seeding_dev) {
2071                 mutex_unlock(&uuid_mutex);
2072                 up_write(&sb->s_umount);
2073
2074                 if (ret) /* transaction commit */
2075                         return ret;
2076
2077                 ret = btrfs_relocate_sys_chunks(root);
2078                 if (ret < 0)
2079                         btrfs_error(root->fs_info, ret,
2080                                     "Failed to relocate sys chunks after "
2081                                     "device initialization. This can be fixed "
2082                                     "using the \"btrfs balance\" command.");
2083                 trans = btrfs_attach_transaction(root);
2084                 if (IS_ERR(trans)) {
2085                         if (PTR_ERR(trans) == -ENOENT)
2086                                 return 0;
2087                         return PTR_ERR(trans);
2088                 }
2089                 ret = btrfs_commit_transaction(trans, root);
2090         }
2091
2092         return ret;
2093
2094 error_trans:
2095         unlock_chunks(root);
2096         btrfs_end_transaction(trans, root);
2097         rcu_string_free(device->name);
2098         kfree(device);
2099 error:
2100         blkdev_put(bdev, FMODE_EXCL);
2101         if (seeding_dev) {
2102                 mutex_unlock(&uuid_mutex);
2103                 up_write(&sb->s_umount);
2104         }
2105         return ret;
2106 }
2107
2108 int btrfs_init_dev_replace_tgtdev(struct btrfs_root *root, char *device_path,
2109                                   struct btrfs_device **device_out)
2110 {
2111         struct request_queue *q;
2112         struct btrfs_device *device;
2113         struct block_device *bdev;
2114         struct btrfs_fs_info *fs_info = root->fs_info;
2115         struct list_head *devices;
2116         struct rcu_string *name;
2117         int ret = 0;
2118
2119         *device_out = NULL;
2120         if (fs_info->fs_devices->seeding)
2121                 return -EINVAL;
2122
2123         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2124                                   fs_info->bdev_holder);
2125         if (IS_ERR(bdev))
2126                 return PTR_ERR(bdev);
2127
2128         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2129
2130         devices = &fs_info->fs_devices->devices;
2131         list_for_each_entry(device, devices, dev_list) {
2132                 if (device->bdev == bdev) {
2133                         ret = -EEXIST;
2134                         goto error;
2135                 }
2136         }
2137
2138         device = kzalloc(sizeof(*device), GFP_NOFS);
2139         if (!device) {
2140                 ret = -ENOMEM;
2141                 goto error;
2142         }
2143
2144         name = rcu_string_strdup(device_path, GFP_NOFS);
2145         if (!name) {
2146                 kfree(device);
2147                 ret = -ENOMEM;
2148                 goto error;
2149         }
2150         rcu_assign_pointer(device->name, name);
2151
2152         q = bdev_get_queue(bdev);
2153         if (blk_queue_discard(q))
2154                 device->can_discard = 1;
2155         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2156         device->writeable = 1;
2157         device->work.func = pending_bios_fn;
2158         generate_random_uuid(device->uuid);
2159         device->devid = BTRFS_DEV_REPLACE_DEVID;
2160         spin_lock_init(&device->io_lock);
2161         device->generation = 0;
2162         device->io_width = root->sectorsize;
2163         device->io_align = root->sectorsize;
2164         device->sector_size = root->sectorsize;
2165         device->total_bytes = i_size_read(bdev->bd_inode);
2166         device->disk_total_bytes = device->total_bytes;
2167         device->dev_root = fs_info->dev_root;
2168         device->bdev = bdev;
2169         device->in_fs_metadata = 1;
2170         device->is_tgtdev_for_dev_replace = 1;
2171         device->mode = FMODE_EXCL;
2172         set_blocksize(device->bdev, 4096);
2173         device->fs_devices = fs_info->fs_devices;
2174         list_add(&device->dev_list, &fs_info->fs_devices->devices);
2175         fs_info->fs_devices->num_devices++;
2176         fs_info->fs_devices->open_devices++;
2177         if (device->can_discard)
2178                 fs_info->fs_devices->num_can_discard++;
2179         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2180
2181         *device_out = device;
2182         return ret;
2183
2184 error:
2185         blkdev_put(bdev, FMODE_EXCL);
2186         return ret;
2187 }
2188
2189 void btrfs_init_dev_replace_tgtdev_for_resume(struct btrfs_fs_info *fs_info,
2190                                               struct btrfs_device *tgtdev)
2191 {
2192         WARN_ON(fs_info->fs_devices->rw_devices == 0);
2193         tgtdev->io_width = fs_info->dev_root->sectorsize;
2194         tgtdev->io_align = fs_info->dev_root->sectorsize;
2195         tgtdev->sector_size = fs_info->dev_root->sectorsize;
2196         tgtdev->dev_root = fs_info->dev_root;
2197         tgtdev->in_fs_metadata = 1;
2198 }
2199
2200 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
2201                                         struct btrfs_device *device)
2202 {
2203         int ret;
2204         struct btrfs_path *path;
2205         struct btrfs_root *root;
2206         struct btrfs_dev_item *dev_item;
2207         struct extent_buffer *leaf;
2208         struct btrfs_key key;
2209
2210         root = device->dev_root->fs_info->chunk_root;
2211
2212         path = btrfs_alloc_path();
2213         if (!path)
2214                 return -ENOMEM;
2215
2216         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2217         key.type = BTRFS_DEV_ITEM_KEY;
2218         key.offset = device->devid;
2219
2220         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2221         if (ret < 0)
2222                 goto out;
2223
2224         if (ret > 0) {
2225                 ret = -ENOENT;
2226                 goto out;
2227         }
2228
2229         leaf = path->nodes[0];
2230         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
2231
2232         btrfs_set_device_id(leaf, dev_item, device->devid);
2233         btrfs_set_device_type(leaf, dev_item, device->type);
2234         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
2235         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
2236         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
2237         btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
2238         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
2239         btrfs_mark_buffer_dirty(leaf);
2240
2241 out:
2242         btrfs_free_path(path);
2243         return ret;
2244 }
2245
2246 static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
2247                       struct btrfs_device *device, u64 new_size)
2248 {
2249         struct btrfs_super_block *super_copy =
2250                 device->dev_root->fs_info->super_copy;
2251         u64 old_total = btrfs_super_total_bytes(super_copy);
2252         u64 diff = new_size - device->total_bytes;
2253
2254         if (!device->writeable)
2255                 return -EACCES;
2256         if (new_size <= device->total_bytes ||
2257             device->is_tgtdev_for_dev_replace)
2258                 return -EINVAL;
2259
2260         btrfs_set_super_total_bytes(super_copy, old_total + diff);
2261         device->fs_devices->total_rw_bytes += diff;
2262
2263         device->total_bytes = new_size;
2264         device->disk_total_bytes = new_size;
2265         btrfs_clear_space_info_full(device->dev_root->fs_info);
2266
2267         return btrfs_update_device(trans, device);
2268 }
2269
2270 int btrfs_grow_device(struct btrfs_trans_handle *trans,
2271                       struct btrfs_device *device, u64 new_size)
2272 {
2273         int ret;
2274         lock_chunks(device->dev_root);
2275         ret = __btrfs_grow_device(trans, device, new_size);
2276         unlock_chunks(device->dev_root);
2277         return ret;
2278 }
2279
2280 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
2281                             struct btrfs_root *root,
2282                             u64 chunk_tree, u64 chunk_objectid,
2283                             u64 chunk_offset)
2284 {
2285         int ret;
2286         struct btrfs_path *path;
2287         struct btrfs_key key;
2288
2289         root = root->fs_info->chunk_root;
2290         path = btrfs_alloc_path();
2291         if (!path)
2292                 return -ENOMEM;
2293
2294         key.objectid = chunk_objectid;
2295         key.offset = chunk_offset;
2296         key.type = BTRFS_CHUNK_ITEM_KEY;
2297
2298         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2299         if (ret < 0)
2300                 goto out;
2301         else if (ret > 0) { /* Logic error or corruption */
2302                 btrfs_error(root->fs_info, -ENOENT,
2303                             "Failed lookup while freeing chunk.");
2304                 ret = -ENOENT;
2305                 goto out;
2306         }
2307
2308         ret = btrfs_del_item(trans, root, path);
2309         if (ret < 0)
2310                 btrfs_error(root->fs_info, ret,
2311                             "Failed to delete chunk item.");
2312 out:
2313         btrfs_free_path(path);
2314         return ret;
2315 }
2316
2317 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
2318                         chunk_offset)
2319 {
2320         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
2321         struct btrfs_disk_key *disk_key;
2322         struct btrfs_chunk *chunk;
2323         u8 *ptr;
2324         int ret = 0;
2325         u32 num_stripes;
2326         u32 array_size;
2327         u32 len = 0;
2328         u32 cur;
2329         struct btrfs_key key;
2330
2331         array_size = btrfs_super_sys_array_size(super_copy);
2332
2333         ptr = super_copy->sys_chunk_array;
2334         cur = 0;
2335
2336         while (cur < array_size) {
2337                 disk_key = (struct btrfs_disk_key *)ptr;
2338                 btrfs_disk_key_to_cpu(&key, disk_key);
2339
2340                 len = sizeof(*disk_key);
2341
2342                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
2343                         chunk = (struct btrfs_chunk *)(ptr + len);
2344                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
2345                         len += btrfs_chunk_item_size(num_stripes);
2346                 } else {
2347                         ret = -EIO;
2348                         break;
2349                 }
2350                 if (key.objectid == chunk_objectid &&
2351                     key.offset == chunk_offset) {
2352                         memmove(ptr, ptr + len, array_size - (cur + len));
2353                         array_size -= len;
2354                         btrfs_set_super_sys_array_size(super_copy, array_size);
2355                 } else {
2356                         ptr += len;
2357                         cur += len;
2358                 }
2359         }
2360         return ret;
2361 }
2362
2363 static int btrfs_relocate_chunk(struct btrfs_root *root,
2364                          u64 chunk_tree, u64 chunk_objectid,
2365                          u64 chunk_offset)
2366 {
2367         struct extent_map_tree *em_tree;
2368         struct btrfs_root *extent_root;
2369         struct btrfs_trans_handle *trans;
2370         struct extent_map *em;
2371         struct map_lookup *map;
2372         int ret;
2373         int i;
2374
2375         root = root->fs_info->chunk_root;
2376         extent_root = root->fs_info->extent_root;
2377         em_tree = &root->fs_info->mapping_tree.map_tree;
2378
2379         ret = btrfs_can_relocate(extent_root, chunk_offset);
2380         if (ret)
2381                 return -ENOSPC;
2382
2383         /* step one, relocate all the extents inside this chunk */
2384         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
2385         if (ret)
2386                 return ret;
2387
2388         trans = btrfs_start_transaction(root, 0);
2389         if (IS_ERR(trans)) {
2390                 ret = PTR_ERR(trans);
2391                 btrfs_std_error(root->fs_info, ret);
2392                 return ret;
2393         }
2394
2395         lock_chunks(root);
2396
2397         /*
2398          * step two, delete the device extents and the
2399          * chunk tree entries
2400          */
2401         read_lock(&em_tree->lock);
2402         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
2403         read_unlock(&em_tree->lock);
2404
2405         BUG_ON(!em || em->start > chunk_offset ||
2406                em->start + em->len < chunk_offset);
2407         map = (struct map_lookup *)em->bdev;
2408
2409         for (i = 0; i < map->num_stripes; i++) {
2410                 ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
2411                                             map->stripes[i].physical);
2412                 BUG_ON(ret);
2413
2414                 if (map->stripes[i].dev) {
2415                         ret = btrfs_update_device(trans, map->stripes[i].dev);
2416                         BUG_ON(ret);
2417                 }
2418         }
2419         ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
2420                                chunk_offset);
2421
2422         BUG_ON(ret);
2423
2424         trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
2425
2426         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2427                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
2428                 BUG_ON(ret);
2429         }
2430
2431         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
2432         BUG_ON(ret);
2433
2434         write_lock(&em_tree->lock);
2435         remove_extent_mapping(em_tree, em);
2436         write_unlock(&em_tree->lock);
2437
2438         kfree(map);
2439         em->bdev = NULL;
2440
2441         /* once for the tree */
2442         free_extent_map(em);
2443         /* once for us */
2444         free_extent_map(em);
2445
2446         unlock_chunks(root);
2447         btrfs_end_transaction(trans, root);
2448         return 0;
2449 }
2450
2451 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
2452 {
2453         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
2454         struct btrfs_path *path;
2455         struct extent_buffer *leaf;
2456         struct btrfs_chunk *chunk;
2457         struct btrfs_key key;
2458         struct btrfs_key found_key;
2459         u64 chunk_tree = chunk_root->root_key.objectid;
2460         u64 chunk_type;
2461         bool retried = false;
2462         int failed = 0;
2463         int ret;
2464
2465         path = btrfs_alloc_path();
2466         if (!path)
2467                 return -ENOMEM;
2468
2469 again:
2470         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2471         key.offset = (u64)-1;
2472         key.type = BTRFS_CHUNK_ITEM_KEY;
2473
2474         while (1) {
2475                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2476                 if (ret < 0)
2477                         goto error;
2478                 BUG_ON(ret == 0); /* Corruption */
2479
2480                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
2481                                           key.type);
2482                 if (ret < 0)
2483                         goto error;
2484                 if (ret > 0)
2485                         break;
2486
2487                 leaf = path->nodes[0];
2488                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2489
2490                 chunk = btrfs_item_ptr(leaf, path->slots[0],
2491                                        struct btrfs_chunk);
2492                 chunk_type = btrfs_chunk_type(leaf, chunk);
2493                 btrfs_release_path(path);
2494
2495                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
2496                         ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
2497                                                    found_key.objectid,
2498                                                    found_key.offset);
2499                         if (ret == -ENOSPC)
2500                                 failed++;
2501                         else if (ret)
2502                                 BUG();
2503                 }
2504
2505                 if (found_key.offset == 0)
2506                         break;
2507                 key.offset = found_key.offset - 1;
2508         }
2509         ret = 0;
2510         if (failed && !retried) {
2511                 failed = 0;
2512                 retried = true;
2513                 goto again;
2514         } else if (failed && retried) {
2515                 WARN_ON(1);
2516                 ret = -ENOSPC;
2517         }
2518 error:
2519         btrfs_free_path(path);
2520         return ret;
2521 }
2522
2523 static int insert_balance_item(struct btrfs_root *root,
2524                                struct btrfs_balance_control *bctl)
2525 {
2526         struct btrfs_trans_handle *trans;
2527         struct btrfs_balance_item *item;
2528         struct btrfs_disk_balance_args disk_bargs;
2529         struct btrfs_path *path;
2530         struct extent_buffer *leaf;
2531         struct btrfs_key key;
2532         int ret, err;
2533
2534         path = btrfs_alloc_path();
2535         if (!path)
2536                 return -ENOMEM;
2537
2538         trans = btrfs_start_transaction(root, 0);
2539         if (IS_ERR(trans)) {
2540                 btrfs_free_path(path);
2541                 return PTR_ERR(trans);
2542         }
2543
2544         key.objectid = BTRFS_BALANCE_OBJECTID;
2545         key.type = BTRFS_BALANCE_ITEM_KEY;
2546         key.offset = 0;
2547
2548         ret = btrfs_insert_empty_item(trans, root, path, &key,
2549                                       sizeof(*item));
2550         if (ret)
2551                 goto out;
2552
2553         leaf = path->nodes[0];
2554         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
2555
2556         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
2557
2558         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);
2559         btrfs_set_balance_data(leaf, item, &disk_bargs);
2560         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->meta);
2561         btrfs_set_balance_meta(leaf, item, &disk_bargs);
2562         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);
2563         btrfs_set_balance_sys(leaf, item, &disk_bargs);
2564
2565         btrfs_set_balance_flags(leaf, item, bctl->flags);
2566
2567         btrfs_mark_buffer_dirty(leaf);
2568 out:
2569         btrfs_free_path(path);
2570         err = btrfs_commit_transaction(trans, root);
2571         if (err && !ret)
2572                 ret = err;
2573         return ret;
2574 }
2575
2576 static int del_balance_item(struct btrfs_root *root)
2577 {
2578         struct btrfs_trans_handle *trans;
2579         struct btrfs_path *path;
2580         struct btrfs_key key;
2581         int ret, err;
2582
2583         path = btrfs_alloc_path();
2584         if (!path)
2585                 return -ENOMEM;
2586
2587         trans = btrfs_start_transaction(root, 0);
2588         if (IS_ERR(trans)) {
2589                 btrfs_free_path(path);
2590                 return PTR_ERR(trans);
2591         }
2592
2593         key.objectid = BTRFS_BALANCE_OBJECTID;
2594         key.type = BTRFS_BALANCE_ITEM_KEY;
2595         key.offset = 0;
2596
2597         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2598         if (ret < 0)
2599                 goto out;
2600         if (ret > 0) {
2601                 ret = -ENOENT;
2602                 goto out;
2603         }
2604
2605         ret = btrfs_del_item(trans, root, path);
2606 out:
2607         btrfs_free_path(path);
2608         err = btrfs_commit_transaction(trans, root);
2609         if (err && !ret)
2610                 ret = err;
2611         return ret;
2612 }
2613
2614 /*
2615  * This is a heuristic used to reduce the number of chunks balanced on
2616  * resume after balance was interrupted.
2617  */
2618 static void update_balance_args(struct btrfs_balance_control *bctl)
2619 {
2620         /*
2621          * Turn on soft mode for chunk types that were being converted.
2622          */
2623         if (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)
2624                 bctl->data.flags |= BTRFS_BALANCE_ARGS_SOFT;
2625         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)
2626                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_SOFT;
2627         if (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)
2628                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_SOFT;
2629
2630         /*
2631          * Turn on usage filter if is not already used.  The idea is
2632          * that chunks that we have already balanced should be
2633          * reasonably full.  Don't do it for chunks that are being
2634          * converted - that will keep us from relocating unconverted
2635          * (albeit full) chunks.
2636          */
2637         if (!(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2638             !(bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2639                 bctl->data.flags |= BTRFS_BALANCE_ARGS_USAGE;
2640                 bctl->data.usage = 90;
2641         }
2642         if (!(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2643             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2644                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_USAGE;
2645                 bctl->sys.usage = 90;
2646         }
2647         if (!(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2648             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2649                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_USAGE;
2650                 bctl->meta.usage = 90;
2651         }
2652 }
2653
2654 /*
2655  * Should be called with both balance and volume mutexes held to
2656  * serialize other volume operations (add_dev/rm_dev/resize) with
2657  * restriper.  Same goes for unset_balance_control.
2658  */
2659 static void set_balance_control(struct btrfs_balance_control *bctl)
2660 {
2661         struct btrfs_fs_info *fs_info = bctl->fs_info;
2662
2663         BUG_ON(fs_info->balance_ctl);
2664
2665         spin_lock(&fs_info->balance_lock);
2666         fs_info->balance_ctl = bctl;
2667         spin_unlock(&fs_info->balance_lock);
2668 }
2669
2670 static void unset_balance_control(struct btrfs_fs_info *fs_info)
2671 {
2672         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2673
2674         BUG_ON(!fs_info->balance_ctl);
2675
2676         spin_lock(&fs_info->balance_lock);
2677         fs_info->balance_ctl = NULL;
2678         spin_unlock(&fs_info->balance_lock);
2679
2680         kfree(bctl);
2681 }
2682
2683 /*
2684  * Balance filters.  Return 1 if chunk should be filtered out
2685  * (should not be balanced).
2686  */
2687 static int chunk_profiles_filter(u64 chunk_type,
2688                                  struct btrfs_balance_args *bargs)
2689 {
2690         chunk_type = chunk_to_extended(chunk_type) &
2691                                 BTRFS_EXTENDED_PROFILE_MASK;
2692
2693         if (bargs->profiles & chunk_type)
2694                 return 0;
2695
2696         return 1;
2697 }
2698
2699 static int chunk_usage_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
2700                               struct btrfs_balance_args *bargs)
2701 {
2702         struct btrfs_block_group_cache *cache;
2703         u64 chunk_used, user_thresh;
2704         int ret = 1;
2705
2706         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
2707         chunk_used = btrfs_block_group_used(&cache->item);
2708
2709         if (bargs->usage == 0)
2710                 user_thresh = 1;
2711         else if (bargs->usage > 100)
2712                 user_thresh = cache->key.offset;
2713         else
2714                 user_thresh = div_factor_fine(cache->key.offset,
2715                                               bargs->usage);
2716
2717         if (chunk_used < user_thresh)
2718                 ret = 0;
2719
2720         btrfs_put_block_group(cache);
2721         return ret;
2722 }
2723
2724 static int chunk_devid_filter(struct extent_buffer *leaf,
2725                               struct btrfs_chunk *chunk,
2726                               struct btrfs_balance_args *bargs)
2727 {
2728         struct btrfs_stripe *stripe;
2729         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2730         int i;
2731
2732         for (i = 0; i < num_stripes; i++) {
2733                 stripe = btrfs_stripe_nr(chunk, i);
2734                 if (btrfs_stripe_devid(leaf, stripe) == bargs->devid)
2735                         return 0;
2736         }
2737
2738         return 1;
2739 }
2740
2741 /* [pstart, pend) */
2742 static int chunk_drange_filter(struct extent_buffer *leaf,
2743                                struct btrfs_chunk *chunk,
2744                                u64 chunk_offset,
2745                                struct btrfs_balance_args *bargs)
2746 {
2747         struct btrfs_stripe *stripe;
2748         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2749         u64 stripe_offset;
2750         u64 stripe_length;
2751         int factor;
2752         int i;
2753
2754         if (!(bargs->flags & BTRFS_BALANCE_ARGS_DEVID))
2755                 return 0;
2756
2757         if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP |
2758              BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)) {
2759                 factor = num_stripes / 2;
2760         } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID5) {
2761                 factor = num_stripes - 1;
2762         } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID6) {
2763                 factor = num_stripes - 2;
2764         } else {
2765                 factor = num_stripes;
2766         }
2767
2768         for (i = 0; i < num_stripes; i++) {
2769                 stripe = btrfs_stripe_nr(chunk, i);
2770                 if (btrfs_stripe_devid(leaf, stripe) != bargs->devid)
2771                         continue;
2772
2773                 stripe_offset = btrfs_stripe_offset(leaf, stripe);
2774                 stripe_length = btrfs_chunk_length(leaf, chunk);
2775                 do_div(stripe_length, factor);
2776
2777                 if (stripe_offset < bargs->pend &&
2778                     stripe_offset + stripe_length > bargs->pstart)
2779                         return 0;
2780         }
2781
2782         return 1;
2783 }
2784
2785 /* [vstart, vend) */
2786 static int chunk_vrange_filter(struct extent_buffer *leaf,
2787                                struct btrfs_chunk *chunk,
2788                                u64 chunk_offset,
2789                                struct btrfs_balance_args *bargs)
2790 {
2791         if (chunk_offset < bargs->vend &&
2792             chunk_offset + btrfs_chunk_length(leaf, chunk) > bargs->vstart)
2793                 /* at least part of the chunk is inside this vrange */
2794                 return 0;
2795
2796         return 1;
2797 }
2798
2799 static int chunk_soft_convert_filter(u64 chunk_type,
2800                                      struct btrfs_balance_args *bargs)
2801 {
2802         if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
2803                 return 0;
2804
2805         chunk_type = chunk_to_extended(chunk_type) &
2806                                 BTRFS_EXTENDED_PROFILE_MASK;
2807
2808         if (bargs->target == chunk_type)
2809                 return 1;
2810
2811         return 0;
2812 }
2813
2814 static int should_balance_chunk(struct btrfs_root *root,
2815                                 struct extent_buffer *leaf,
2816                                 struct btrfs_chunk *chunk, u64 chunk_offset)
2817 {
2818         struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
2819         struct btrfs_balance_args *bargs = NULL;
2820         u64 chunk_type = btrfs_chunk_type(leaf, chunk);
2821
2822         /* type filter */
2823         if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
2824               (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
2825                 return 0;
2826         }
2827
2828         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
2829                 bargs = &bctl->data;
2830         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
2831                 bargs = &bctl->sys;
2832         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
2833                 bargs = &bctl->meta;
2834
2835         /* profiles filter */
2836         if ((bargs->flags & BTRFS_BALANCE_ARGS_PROFILES) &&
2837             chunk_profiles_filter(chunk_type, bargs)) {
2838                 return 0;
2839         }
2840
2841         /* usage filter */
2842         if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
2843             chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
2844                 return 0;
2845         }
2846
2847         /* devid filter */
2848         if ((bargs->flags & BTRFS_BALANCE_ARGS_DEVID) &&
2849             chunk_devid_filter(leaf, chunk, bargs)) {
2850                 return 0;
2851         }
2852
2853         /* drange filter, makes sense only with devid filter */
2854         if ((bargs->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
2855             chunk_drange_filter(leaf, chunk, chunk_offset, bargs)) {
2856                 return 0;
2857         }
2858
2859         /* vrange filter */
2860         if ((bargs->flags & BTRFS_BALANCE_ARGS_VRANGE) &&
2861             chunk_vrange_filter(leaf, chunk, chunk_offset, bargs)) {
2862                 return 0;
2863         }
2864
2865         /* soft profile changing mode */
2866         if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
2867             chunk_soft_convert_filter(chunk_type, bargs)) {
2868                 return 0;
2869         }
2870
2871         return 1;
2872 }
2873
2874 static int __btrfs_balance(struct btrfs_fs_info *fs_info)
2875 {
2876         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2877         struct btrfs_root *chunk_root = fs_info->chunk_root;
2878         struct btrfs_root *dev_root = fs_info->dev_root;
2879         struct list_head *devices;
2880         struct btrfs_device *device;
2881         u64 old_size;
2882         u64 size_to_free;
2883         struct btrfs_chunk *chunk;
2884         struct btrfs_path *path;
2885         struct btrfs_key key;
2886         struct btrfs_key found_key;
2887         struct btrfs_trans_handle *trans;
2888         struct extent_buffer *leaf;
2889         int slot;
2890         int ret;
2891         int enospc_errors = 0;
2892         bool counting = true;
2893
2894         /* step one make some room on all the devices */
2895         devices = &fs_info->fs_devices->devices;
2896         list_for_each_entry(device, devices, dev_list) {
2897                 old_size = device->total_bytes;
2898                 size_to_free = div_factor(old_size, 1);
2899                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
2900                 if (!device->writeable ||
2901                     device->total_bytes - device->bytes_used > size_to_free ||
2902                     device->is_tgtdev_for_dev_replace)
2903                         continue;
2904
2905                 ret = btrfs_shrink_device(device, old_size - size_to_free);
2906                 if (ret == -ENOSPC)
2907                         break;
2908                 BUG_ON(ret);
2909
2910                 trans = btrfs_start_transaction(dev_root, 0);
2911                 BUG_ON(IS_ERR(trans));
2912
2913                 ret = btrfs_grow_device(trans, device, old_size);
2914                 BUG_ON(ret);
2915
2916                 btrfs_end_transaction(trans, dev_root);
2917         }
2918
2919         /* step two, relocate all the chunks */
2920         path = btrfs_alloc_path();
2921         if (!path) {
2922                 ret = -ENOMEM;
2923                 goto error;
2924         }
2925
2926         /* zero out stat counters */
2927         spin_lock(&fs_info->balance_lock);
2928         memset(&bctl->stat, 0, sizeof(bctl->stat));
2929         spin_unlock(&fs_info->balance_lock);
2930 again:
2931         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2932         key.offset = (u64)-1;
2933         key.type = BTRFS_CHUNK_ITEM_KEY;
2934
2935         while (1) {
2936                 if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
2937                     atomic_read(&fs_info->balance_cancel_req)) {
2938                         ret = -ECANCELED;
2939                         goto error;
2940                 }
2941
2942                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2943                 if (ret < 0)
2944                         goto error;
2945
2946                 /*
2947                  * this shouldn't happen, it means the last relocate
2948                  * failed
2949                  */
2950                 if (ret == 0)
2951                         BUG(); /* FIXME break ? */
2952
2953                 ret = btrfs_previous_item(chunk_root, path, 0,
2954                                           BTRFS_CHUNK_ITEM_KEY);
2955                 if (ret) {
2956                         ret = 0;
2957                         break;
2958                 }
2959
2960                 leaf = path->nodes[0];
2961                 slot = path->slots[0];
2962                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2963
2964                 if (found_key.objectid != key.objectid)
2965                         break;
2966
2967                 /* chunk zero is special */
2968                 if (found_key.offset == 0)
2969                         break;
2970
2971                 chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
2972
2973                 if (!counting) {
2974                         spin_lock(&fs_info->balance_lock);
2975                         bctl->stat.considered++;
2976                         spin_unlock(&fs_info->balance_lock);
2977                 }
2978
2979                 ret = should_balance_chunk(chunk_root, leaf, chunk,
2980                                            found_key.offset);
2981                 btrfs_release_path(path);
2982                 if (!ret)
2983                         goto loop;
2984
2985                 if (counting) {
2986                         spin_lock(&fs_info->balance_lock);
2987                         bctl->stat.expected++;
2988                         spin_unlock(&fs_info->balance_lock);
2989                         goto loop;
2990                 }
2991
2992                 ret = btrfs_relocate_chunk(chunk_root,
2993                                            chunk_root->root_key.objectid,
2994                                            found_key.objectid,
2995                                            found_key.offset);
2996                 if (ret && ret != -ENOSPC)
2997                         goto error;
2998                 if (ret == -ENOSPC) {
2999                         enospc_errors++;
3000                 } else {
3001                         spin_lock(&fs_info->balance_lock);
3002                         bctl->stat.completed++;
3003                         spin_unlock(&fs_info->balance_lock);
3004                 }
3005 loop:
3006                 key.offset = found_key.offset - 1;
3007         }
3008
3009         if (counting) {
3010                 btrfs_release_path(path);
3011                 counting = false;
3012                 goto again;
3013         }
3014 error:
3015         btrfs_free_path(path);
3016         if (enospc_errors) {
3017                 printk(KERN_INFO "btrfs: %d enospc errors during balance\n",
3018                        enospc_errors);
3019                 if (!ret)
3020                         ret = -ENOSPC;
3021         }
3022
3023         return ret;
3024 }
3025
3026 /**
3027  * alloc_profile_is_valid - see if a given profile is valid and reduced
3028  * @flags: profile to validate
3029  * @extended: if true @flags is treated as an extended profile
3030  */
3031 static int alloc_profile_is_valid(u64 flags, int extended)
3032 {
3033         u64 mask = (extended ? BTRFS_EXTENDED_PROFILE_MASK :
3034                                BTRFS_BLOCK_GROUP_PROFILE_MASK);
3035
3036         flags &= ~BTRFS_BLOCK_GROUP_TYPE_MASK;
3037
3038         /* 1) check that all other bits are zeroed */
3039         if (flags & ~mask)
3040                 return 0;
3041
3042         /* 2) see if profile is reduced */
3043         if (flags == 0)
3044                 return !extended; /* "0" is valid for usual profiles */
3045
3046         /* true if exactly one bit set */
3047         return (flags & (flags - 1)) == 0;
3048 }
3049
3050 static inline int balance_need_close(struct btrfs_fs_info *fs_info)
3051 {
3052         /* cancel requested || normal exit path */
3053         return atomic_read(&fs_info->balance_cancel_req) ||
3054                 (atomic_read(&fs_info->balance_pause_req) == 0 &&
3055                  atomic_read(&fs_info->balance_cancel_req) == 0);
3056 }
3057
3058 static void __cancel_balance(struct btrfs_fs_info *fs_info)
3059 {
3060         int ret;
3061
3062         unset_balance_control(fs_info);
3063         ret = del_balance_item(fs_info->tree_root);
3064         if (ret)
3065                 btrfs_std_error(fs_info, ret);
3066
3067         atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3068 }
3069
3070 void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
3071                                struct btrfs_ioctl_balance_args *bargs);
3072
3073 /*
3074  * Should be called with both balance and volume mutexes held
3075  */
3076 int btrfs_balance(struct btrfs_balance_control *bctl,
3077                   struct btrfs_ioctl_balance_args *bargs)
3078 {
3079         struct btrfs_fs_info *fs_info = bctl->fs_info;
3080         u64 allowed;
3081         int mixed = 0;
3082         int ret;
3083         u64 num_devices;
3084         unsigned seq;
3085
3086         if (btrfs_fs_closing(fs_info) ||
3087             atomic_read(&fs_info->balance_pause_req) ||
3088             atomic_read(&fs_info->balance_cancel_req)) {
3089                 ret = -EINVAL;
3090                 goto out;
3091         }
3092
3093         allowed = btrfs_super_incompat_flags(fs_info->super_copy);
3094         if (allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
3095                 mixed = 1;
3096
3097         /*
3098          * In case of mixed groups both data and meta should be picked,
3099          * and identical options should be given for both of them.
3100          */
3101         allowed = BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA;
3102         if (mixed && (bctl->flags & allowed)) {
3103                 if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
3104                     !(bctl->flags & BTRFS_BALANCE_METADATA) ||
3105                     memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
3106                         printk(KERN_ERR "btrfs: with mixed groups data and "
3107                                "metadata balance options must be the same\n");
3108                         ret = -EINVAL;
3109                         goto out;
3110                 }
3111         }
3112
3113         num_devices = fs_info->fs_devices->num_devices;
3114         btrfs_dev_replace_lock(&fs_info->dev_replace);
3115         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) {
3116                 BUG_ON(num_devices < 1);
3117                 num_devices--;
3118         }
3119         btrfs_dev_replace_unlock(&fs_info->dev_replace);
3120         allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
3121         if (num_devices == 1)
3122                 allowed |= BTRFS_BLOCK_GROUP_DUP;
3123         else if (num_devices > 1)
3124                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
3125         if (num_devices > 2)
3126                 allowed |= BTRFS_BLOCK_GROUP_RAID5;
3127         if (num_devices > 3)
3128                 allowed |= (BTRFS_BLOCK_GROUP_RAID10 |
3129                             BTRFS_BLOCK_GROUP_RAID6);
3130         if ((bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3131             (!alloc_profile_is_valid(bctl->data.target, 1) ||
3132              (bctl->data.target & ~allowed))) {
3133                 printk(KERN_ERR "btrfs: unable to start balance with target "
3134                        "data profile %llu\n",
3135                        (unsigned long long)bctl->data.target);
3136                 ret = -EINVAL;
3137                 goto out;
3138         }
3139         if ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3140             (!alloc_profile_is_valid(bctl->meta.target, 1) ||
3141              (bctl->meta.target & ~allowed))) {
3142                 printk(KERN_ERR "btrfs: unable to start balance with target "
3143                        "metadata profile %llu\n",
3144                        (unsigned long long)bctl->meta.target);
3145                 ret = -EINVAL;
3146                 goto out;
3147         }
3148         if ((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3149             (!alloc_profile_is_valid(bctl->sys.target, 1) ||
3150              (bctl->sys.target & ~allowed))) {
3151                 printk(KERN_ERR "btrfs: unable to start balance with target "
3152                        "system profile %llu\n",
3153                        (unsigned long long)bctl->sys.target);
3154                 ret = -EINVAL;
3155                 goto out;
3156         }
3157
3158         /* allow dup'ed data chunks only in mixed mode */
3159         if (!mixed && (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3160             (bctl->data.target & BTRFS_BLOCK_GROUP_DUP)) {
3161                 printk(KERN_ERR "btrfs: dup for data is not allowed\n");
3162                 ret = -EINVAL;
3163                 goto out;
3164         }
3165
3166         /* allow to reduce meta or sys integrity only if force set */
3167         allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3168                         BTRFS_BLOCK_GROUP_RAID10 |
3169                         BTRFS_BLOCK_GROUP_RAID5 |
3170                         BTRFS_BLOCK_GROUP_RAID6;
3171         do {
3172                 seq = read_seqbegin(&fs_info->profiles_lock);
3173
3174                 if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3175                      (fs_info->avail_system_alloc_bits & allowed) &&
3176                      !(bctl->sys.target & allowed)) ||
3177                     ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3178                      (fs_info->avail_metadata_alloc_bits & allowed) &&
3179                      !(bctl->meta.target & allowed))) {
3180                         if (bctl->flags & BTRFS_BALANCE_FORCE) {
3181                                 printk(KERN_INFO "btrfs: force reducing metadata "
3182                                        "integrity\n");
3183                         } else {
3184                                 printk(KERN_ERR "btrfs: balance will reduce metadata "
3185                                        "integrity, use force if you want this\n");
3186                                 ret = -EINVAL;
3187                                 goto out;
3188                         }
3189                 }
3190         } while (read_seqretry(&fs_info->profiles_lock, seq));
3191
3192         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3193                 int num_tolerated_disk_barrier_failures;
3194                 u64 target = bctl->sys.target;
3195
3196                 num_tolerated_disk_barrier_failures =
3197                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3198                 if (num_tolerated_disk_barrier_failures > 0 &&
3199                     (target &
3200                      (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3201                       BTRFS_AVAIL_ALLOC_BIT_SINGLE)))
3202                         num_tolerated_disk_barrier_failures = 0;
3203                 else if (num_tolerated_disk_barrier_failures > 1 &&
3204                          (target &
3205                           (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)))
3206                         num_tolerated_disk_barrier_failures = 1;
3207
3208                 fs_info->num_tolerated_disk_barrier_failures =
3209                         num_tolerated_disk_barrier_failures;
3210         }
3211
3212         ret = insert_balance_item(fs_info->tree_root, bctl);
3213         if (ret && ret != -EEXIST)
3214                 goto out;
3215
3216         if (!(bctl->flags & BTRFS_BALANCE_RESUME)) {
3217                 BUG_ON(ret == -EEXIST);
3218                 set_balance_control(bctl);
3219         } else {
3220                 BUG_ON(ret != -EEXIST);
3221                 spin_lock(&fs_info->balance_lock);
3222                 update_balance_args(bctl);
3223                 spin_unlock(&fs_info->balance_lock);
3224         }
3225
3226         atomic_inc(&fs_info->balance_running);
3227         mutex_unlock(&fs_info->balance_mutex);
3228
3229         ret = __btrfs_balance(fs_info);
3230
3231         mutex_lock(&fs_info->balance_mutex);
3232         atomic_dec(&fs_info->balance_running);
3233
3234         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3235                 fs_info->num_tolerated_disk_barrier_failures =
3236                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3237         }
3238
3239         if (bargs) {
3240                 memset(bargs, 0, sizeof(*bargs));
3241                 update_ioctl_balance_args(fs_info, 0, bargs);
3242         }
3243
3244         if ((ret && ret != -ECANCELED && ret != -ENOSPC) ||
3245             balance_need_close(fs_info)) {
3246                 __cancel_balance(fs_info);
3247         }
3248
3249         wake_up(&fs_info->balance_wait_q);
3250
3251         return ret;
3252 out:
3253         if (bctl->flags & BTRFS_BALANCE_RESUME)
3254                 __cancel_balance(fs_info);
3255         else {
3256                 kfree(bctl);
3257                 atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3258         }
3259         return ret;
3260 }
3261
3262 static int balance_kthread(void *data)
3263 {
3264         struct btrfs_fs_info *fs_info = data;
3265         int ret = 0;
3266
3267         mutex_lock(&fs_info->volume_mutex);
3268         mutex_lock(&fs_info->balance_mutex);
3269
3270         if (fs_info->balance_ctl) {
3271                 printk(KERN_INFO "btrfs: continuing balance\n");
3272                 ret = btrfs_balance(fs_info->balance_ctl, NULL);
3273         }
3274
3275         mutex_unlock(&fs_info->balance_mutex);
3276         mutex_unlock(&fs_info->volume_mutex);
3277
3278         return ret;
3279 }
3280
3281 int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
3282 {
3283         struct task_struct *tsk;
3284
3285         spin_lock(&fs_info->balance_lock);
3286         if (!fs_info->balance_ctl) {
3287                 spin_unlock(&fs_info->balance_lock);
3288                 return 0;
3289         }
3290         spin_unlock(&fs_info->balance_lock);
3291
3292         if (btrfs_test_opt(fs_info->tree_root, SKIP_BALANCE)) {
3293                 printk(KERN_INFO "btrfs: force skipping balance\n");
3294                 return 0;
3295         }
3296
3297         tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");
3298         if (IS_ERR(tsk))
3299                 return PTR_ERR(tsk);
3300
3301         return 0;
3302 }
3303
3304 int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
3305 {
3306         struct btrfs_balance_control *bctl;
3307         struct btrfs_balance_item *item;
3308         struct btrfs_disk_balance_args disk_bargs;
3309         struct btrfs_path *path;
3310         struct extent_buffer *leaf;
3311         struct btrfs_key key;
3312         int ret;
3313
3314         path = btrfs_alloc_path();
3315         if (!path)
3316                 return -ENOMEM;
3317
3318         key.objectid = BTRFS_BALANCE_OBJECTID;
3319         key.type = BTRFS_BALANCE_ITEM_KEY;
3320         key.offset = 0;
3321
3322         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
3323         if (ret < 0)
3324                 goto out;
3325         if (ret > 0) { /* ret = -ENOENT; */
3326                 ret = 0;
3327                 goto out;
3328         }
3329
3330         bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
3331         if (!bctl) {
3332                 ret = -ENOMEM;
3333                 goto out;
3334         }
3335
3336         leaf = path->nodes[0];
3337         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
3338
3339         bctl->fs_info = fs_info;
3340         bctl->flags = btrfs_balance_flags(leaf, item);
3341         bctl->flags |= BTRFS_BALANCE_RESUME;
3342
3343         btrfs_balance_data(leaf, item, &disk_bargs);
3344         btrfs_disk_balance_args_to_cpu(&bctl->data, &disk_bargs);
3345         btrfs_balance_meta(leaf, item, &disk_bargs);
3346         btrfs_disk_balance_args_to_cpu(&bctl->meta, &disk_bargs);
3347         btrfs_balance_sys(leaf, item, &disk_bargs);
3348         btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
3349
3350         WARN_ON(atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1));
3351
3352         mutex_lock(&fs_info->volume_mutex);
3353         mutex_lock(&fs_info->balance_mutex);
3354
3355         set_balance_control(bctl);
3356
3357         mutex_unlock(&fs_info->balance_mutex);
3358         mutex_unlock(&fs_info->volume_mutex);
3359 out:
3360         btrfs_free_path(path);
3361         return ret;
3362 }
3363
3364 int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
3365 {
3366         int ret = 0;
3367
3368         mutex_lock(&fs_info->balance_mutex);
3369         if (!fs_info->balance_ctl) {
3370                 mutex_unlock(&fs_info->balance_mutex);
3371                 return -ENOTCONN;
3372         }
3373
3374         if (atomic_read(&fs_info->balance_running)) {
3375                 atomic_inc(&fs_info->balance_pause_req);
3376                 mutex_unlock(&fs_info->balance_mutex);
3377
3378                 wait_event(fs_info->balance_wait_q,
3379                            atomic_read(&fs_info->balance_running) == 0);
3380
3381                 mutex_lock(&fs_info->balance_mutex);
3382                 /* we are good with balance_ctl ripped off from under us */
3383                 BUG_ON(atomic_read(&fs_info->balance_running));
3384                 atomic_dec(&fs_info->balance_pause_req);
3385         } else {
3386                 ret = -ENOTCONN;
3387         }
3388
3389         mutex_unlock(&fs_info->balance_mutex);
3390         return ret;
3391 }
3392
3393 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
3394 {
3395         mutex_lock(&fs_info->balance_mutex);
3396         if (!fs_info->balance_ctl) {
3397                 mutex_unlock(&fs_info->balance_mutex);
3398                 return -ENOTCONN;
3399         }
3400
3401         atomic_inc(&fs_info->balance_cancel_req);
3402         /*
3403          * if we are running just wait and return, balance item is
3404          * deleted in btrfs_balance in this case
3405          */
3406         if (atomic_read(&fs_info->balance_running)) {
3407                 mutex_unlock(&fs_info->balance_mutex);
3408                 wait_event(fs_info->balance_wait_q,
3409                            atomic_read(&fs_info->balance_running) == 0);
3410                 mutex_lock(&fs_info->balance_mutex);
3411         } else {
3412                 /* __cancel_balance needs volume_mutex */
3413                 mutex_unlock(&fs_info->balance_mutex);
3414                 mutex_lock(&fs_info->volume_mutex);
3415                 mutex_lock(&fs_info->balance_mutex);
3416
3417                 if (fs_info->balance_ctl)
3418                         __cancel_balance(fs_info);
3419
3420                 mutex_unlock(&fs_info->volume_mutex);
3421         }
3422
3423         BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
3424         atomic_dec(&fs_info->balance_cancel_req);
3425         mutex_unlock(&fs_info->balance_mutex);
3426         return 0;
3427 }
3428
3429 /*
3430  * shrinking a device means finding all of the device extents past
3431  * the new size, and then following the back refs to the chunks.
3432  * The chunk relocation code actually frees the device extent
3433  */
3434 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
3435 {
3436         struct btrfs_trans_handle *trans;
3437         struct btrfs_root *root = device->dev_root;
3438         struct btrfs_dev_extent *dev_extent = NULL;
3439         struct btrfs_path *path;
3440         u64 length;
3441         u64 chunk_tree;
3442         u64 chunk_objectid;
3443         u64 chunk_offset;
3444         int ret;
3445         int slot;
3446         int failed = 0;
3447         bool retried = false;
3448         struct extent_buffer *l;
3449         struct btrfs_key key;
3450         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3451         u64 old_total = btrfs_super_total_bytes(super_copy);
3452         u64 old_size = device->total_bytes;
3453         u64 diff = device->total_bytes - new_size;
3454
3455         if (device->is_tgtdev_for_dev_replace)
3456                 return -EINVAL;
3457
3458         path = btrfs_alloc_path();
3459         if (!path)
3460                 return -ENOMEM;
3461
3462         path->reada = 2;
3463
3464         lock_chunks(root);
3465
3466         device->total_bytes = new_size;
3467         if (device->writeable) {
3468                 device->fs_devices->total_rw_bytes -= diff;
3469                 spin_lock(&root->fs_info->free_chunk_lock);
3470                 root->fs_info->free_chunk_space -= diff;
3471                 spin_unlock(&root->fs_info->free_chunk_lock);
3472         }
3473         unlock_chunks(root);
3474
3475 again:
3476         key.objectid = device->devid;
3477         key.offset = (u64)-1;
3478         key.type = BTRFS_DEV_EXTENT_KEY;
3479
3480         do {
3481                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3482                 if (ret < 0)
3483                         goto done;
3484
3485                 ret = btrfs_previous_item(root, path, 0, key.type);
3486                 if (ret < 0)
3487                         goto done;
3488                 if (ret) {
3489                         ret = 0;
3490                         btrfs_release_path(path);
3491                         break;
3492                 }
3493
3494                 l = path->nodes[0];
3495                 slot = path->slots[0];
3496                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
3497
3498                 if (key.objectid != device->devid) {
3499                         btrfs_release_path(path);
3500                         break;
3501                 }
3502
3503                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
3504                 length = btrfs_dev_extent_length(l, dev_extent);
3505
3506                 if (key.offset + length <= new_size) {
3507                         btrfs_release_path(path);
3508                         break;
3509                 }
3510
3511                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
3512                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
3513                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
3514                 btrfs_release_path(path);
3515
3516                 ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
3517                                            chunk_offset);
3518                 if (ret && ret != -ENOSPC)
3519                         goto done;
3520                 if (ret == -ENOSPC)
3521                         failed++;
3522         } while (key.offset-- > 0);
3523
3524         if (failed && !retried) {
3525                 failed = 0;
3526                 retried = true;
3527                 goto again;
3528         } else if (failed && retried) {
3529                 ret = -ENOSPC;
3530                 lock_chunks(root);
3531
3532                 device->total_bytes = old_size;
3533                 if (device->writeable)
3534                         device->fs_devices->total_rw_bytes += diff;
3535                 spin_lock(&root->fs_info->free_chunk_lock);
3536                 root->fs_info->free_chunk_space += diff;
3537                 spin_unlock(&root->fs_info->free_chunk_lock);
3538                 unlock_chunks(root);
3539                 goto done;
3540         }
3541
3542         /* Shrinking succeeded, else we would be at "done". */
3543         trans = btrfs_start_transaction(root, 0);
3544         if (IS_ERR(trans)) {
3545                 ret = PTR_ERR(trans);
3546                 goto done;
3547         }
3548
3549         lock_chunks(root);
3550
3551         device->disk_total_bytes = new_size;
3552         /* Now btrfs_update_device() will change the on-disk size. */
3553         ret = btrfs_update_device(trans, device);
3554         if (ret) {
3555                 unlock_chunks(root);
3556                 btrfs_end_transaction(trans, root);
3557                 goto done;
3558         }
3559         WARN_ON(diff > old_total);
3560         btrfs_set_super_total_bytes(super_copy, old_total - diff);
3561         unlock_chunks(root);
3562         btrfs_end_transaction(trans, root);
3563 done:
3564         btrfs_free_path(path);
3565         return ret;
3566 }
3567
3568 static int btrfs_add_system_chunk(struct btrfs_root *root,
3569                            struct btrfs_key *key,
3570                            struct btrfs_chunk *chunk, int item_size)
3571 {
3572         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3573         struct btrfs_disk_key disk_key;
3574         u32 array_size;
3575         u8 *ptr;
3576
3577         array_size = btrfs_super_sys_array_size(super_copy);
3578         if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
3579                 return -EFBIG;
3580
3581         ptr = super_copy->sys_chunk_array + array_size;
3582         btrfs_cpu_key_to_disk(&disk_key, key);
3583         memcpy(ptr, &disk_key, sizeof(disk_key));
3584         ptr += sizeof(disk_key);
3585         memcpy(ptr, chunk, item_size);
3586         item_size += sizeof(disk_key);
3587         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
3588         return 0;
3589 }
3590
3591 /*
3592  * sort the devices in descending order by max_avail, total_avail
3593  */
3594 static int btrfs_cmp_device_info(const void *a, const void *b)
3595 {
3596         const struct btrfs_device_info *di_a = a;
3597         const struct btrfs_device_info *di_b = b;
3598
3599         if (di_a->max_avail > di_b->max_avail)
3600                 return -1;
3601         if (di_a->max_avail < di_b->max_avail)
3602                 return 1;
3603         if (di_a->total_avail > di_b->total_avail)
3604                 return -1;
3605         if (di_a->total_avail < di_b->total_avail)
3606                 return 1;
3607         return 0;
3608 }
3609
3610 static struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
3611         [BTRFS_RAID_RAID10] = {
3612                 .sub_stripes    = 2,
3613                 .dev_stripes    = 1,
3614                 .devs_max       = 0,    /* 0 == as many as possible */
3615                 .devs_min       = 4,
3616                 .devs_increment = 2,
3617                 .ncopies        = 2,
3618         },
3619         [BTRFS_RAID_RAID1] = {
3620                 .sub_stripes    = 1,
3621                 .dev_stripes    = 1,
3622                 .devs_max       = 2,
3623                 .devs_min       = 2,
3624                 .devs_increment = 2,
3625                 .ncopies        = 2,
3626         },
3627         [BTRFS_RAID_DUP] = {
3628                 .sub_stripes    = 1,
3629                 .dev_stripes    = 2,
3630                 .devs_max       = 1,
3631                 .devs_min       = 1,
3632                 .devs_increment = 1,
3633                 .ncopies        = 2,
3634         },
3635         [BTRFS_RAID_RAID0] = {
3636                 .sub_stripes    = 1,
3637                 .dev_stripes    = 1,
3638                 .devs_max       = 0,
3639                 .devs_min       = 2,
3640                 .devs_increment = 1,
3641                 .ncopies        = 1,
3642         },
3643         [BTRFS_RAID_SINGLE] = {
3644                 .sub_stripes    = 1,
3645                 .dev_stripes    = 1,
3646                 .devs_max       = 1,
3647                 .devs_min       = 1,
3648                 .devs_increment = 1,
3649                 .ncopies        = 1,
3650         },
3651         [BTRFS_RAID_RAID5] = {
3652                 .sub_stripes    = 1,
3653                 .dev_stripes    = 1,
3654                 .devs_max       = 0,
3655                 .devs_min       = 2,
3656                 .devs_increment = 1,
3657                 .ncopies        = 2,
3658         },
3659         [BTRFS_RAID_RAID6] = {
3660                 .sub_stripes    = 1,
3661                 .dev_stripes    = 1,
3662                 .devs_max       = 0,
3663                 .devs_min       = 3,
3664                 .devs_increment = 1,
3665                 .ncopies        = 3,
3666         },
3667 };
3668
3669 static u32 find_raid56_stripe_len(u32 data_devices, u32 dev_stripe_target)
3670 {
3671         /* TODO allow them to set a preferred stripe size */
3672         return 64 * 1024;
3673 }
3674
3675 static void check_raid56_incompat_flag(struct btrfs_fs_info *info, u64 type)
3676 {
3677         if (!(type & (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6)))
3678                 return;
3679
3680         btrfs_set_fs_incompat(info, RAID56);
3681 }
3682
3683 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
3684                                struct btrfs_root *extent_root,
3685                                struct map_lookup **map_ret,
3686                                u64 *num_bytes_out, u64 *stripe_size_out,
3687                                u64 start, u64 type)
3688 {
3689         struct btrfs_fs_info *info = extent_root->fs_info;
3690         struct btrfs_fs_devices *fs_devices = info->fs_devices;
3691         struct list_head *cur;
3692         struct map_lookup *map = NULL;
3693         struct extent_map_tree *em_tree;
3694         struct extent_map *em;
3695         struct btrfs_device_info *devices_info = NULL;
3696         u64 total_avail;
3697         int num_stripes;        /* total number of stripes to allocate */
3698         int data_stripes;       /* number of stripes that count for
3699                                    block group size */
3700         int sub_stripes;        /* sub_stripes info for map */
3701         int dev_stripes;        /* stripes per dev */
3702         int devs_max;           /* max devs to use */
3703         int devs_min;           /* min devs needed */
3704         int devs_increment;     /* ndevs has to be a multiple of this */
3705         int ncopies;            /* how many copies to data has */
3706         int ret;
3707         u64 max_stripe_size;
3708         u64 max_chunk_size;
3709         u64 stripe_size;
3710         u64 num_bytes;
3711         u64 raid_stripe_len = BTRFS_STRIPE_LEN;
3712         int ndevs;
3713         int i;
3714         int j;
3715         int index;
3716
3717         BUG_ON(!alloc_profile_is_valid(type, 0));
3718
3719         if (list_empty(&fs_devices->alloc_list))
3720                 return -ENOSPC;
3721
3722         index = __get_raid_index(type);
3723
3724         sub_stripes = btrfs_raid_array[index].sub_stripes;
3725         dev_stripes = btrfs_raid_array[index].dev_stripes;
3726         devs_max = btrfs_raid_array[index].devs_max;
3727         devs_min = btrfs_raid_array[index].devs_min;
3728         devs_increment = btrfs_raid_array[index].devs_increment;
3729         ncopies = btrfs_raid_array[index].ncopies;
3730
3731         if (type & BTRFS_BLOCK_GROUP_DATA) {
3732                 max_stripe_size = 1024 * 1024 * 1024;
3733                 max_chunk_size = 10 * max_stripe_size;
3734         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
3735                 /* for larger filesystems, use larger metadata chunks */
3736                 if (fs_devices->total_rw_bytes > 50ULL * 1024 * 1024 * 1024)
3737                         max_stripe_size = 1024 * 1024 * 1024;
3738                 else
3739                         max_stripe_size = 256 * 1024 * 1024;
3740                 max_chunk_size = max_stripe_size;
3741         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
3742                 max_stripe_size = 32 * 1024 * 1024;
3743                 max_chunk_size = 2 * max_stripe_size;
3744         } else {
3745                 printk(KERN_ERR "btrfs: invalid chunk type 0x%llx requested\n",
3746                        type);
3747                 BUG_ON(1);
3748         }
3749
3750         /* we don't want a chunk larger than 10% of writeable space */
3751         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
3752                              max_chunk_size);
3753
3754         devices_info = kzalloc(sizeof(*devices_info) * fs_devices->rw_devices,
3755                                GFP_NOFS);
3756         if (!devices_info)
3757                 return -ENOMEM;
3758
3759         cur = fs_devices->alloc_list.next;
3760
3761         /*
3762          * in the first pass through the devices list, we gather information
3763          * about the available holes on each device.
3764          */
3765         ndevs = 0;
3766         while (cur != &fs_devices->alloc_list) {
3767                 struct btrfs_device *device;
3768                 u64 max_avail;
3769                 u64 dev_offset;
3770
3771                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
3772
3773                 cur = cur->next;
3774
3775                 if (!device->writeable) {
3776                         WARN(1, KERN_ERR
3777                                "btrfs: read-only device in alloc_list\n");
3778                         continue;
3779                 }
3780
3781                 if (!device->in_fs_metadata ||
3782                     device->is_tgtdev_for_dev_replace)
3783                         continue;
3784
3785                 if (device->total_bytes > device->bytes_used)
3786                         total_avail = device->total_bytes - device->bytes_used;
3787                 else
3788                         total_avail = 0;
3789
3790                 /* If there is no space on this device, skip it. */
3791                 if (total_avail == 0)
3792                         continue;
3793
3794                 ret = find_free_dev_extent(device,
3795                                            max_stripe_size * dev_stripes,
3796                                            &dev_offset, &max_avail);
3797                 if (ret && ret != -ENOSPC)
3798                         goto error;
3799
3800                 if (ret == 0)
3801                         max_avail = max_stripe_size * dev_stripes;
3802
3803                 if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
3804                         continue;
3805
3806                 if (ndevs == fs_devices->rw_devices) {
3807                         WARN(1, "%s: found more than %llu devices\n",
3808                              __func__, fs_devices->rw_devices);
3809                         break;
3810                 }
3811                 devices_info[ndevs].dev_offset = dev_offset;
3812                 devices_info[ndevs].max_avail = max_avail;
3813                 devices_info[ndevs].total_avail = total_avail;
3814                 devices_info[ndevs].dev = device;
3815                 ++ndevs;
3816         }
3817
3818         /*
3819          * now sort the devices by hole size / available space
3820          */
3821         sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
3822              btrfs_cmp_device_info, NULL);
3823
3824         /* round down to number of usable stripes */
3825         ndevs -= ndevs % devs_increment;
3826
3827         if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
3828                 ret = -ENOSPC;
3829                 goto error;
3830         }
3831
3832         if (devs_max && ndevs > devs_max)
3833                 ndevs = devs_max;
3834         /*
3835          * the primary goal is to maximize the number of stripes, so use as many
3836          * devices as possible, even if the stripes are not maximum sized.
3837          */
3838         stripe_size = devices_info[ndevs-1].max_avail;
3839         num_stripes = ndevs * dev_stripes;
3840
3841         /*
3842          * this will have to be fixed for RAID1 and RAID10 over
3843          * more drives
3844          */
3845         data_stripes = num_stripes / ncopies;
3846
3847         if (type & BTRFS_BLOCK_GROUP_RAID5) {
3848                 raid_stripe_len = find_raid56_stripe_len(ndevs - 1,
3849                                  btrfs_super_stripesize(info->super_copy));
3850                 data_stripes = num_stripes - 1;
3851         }
3852         if (type & BTRFS_BLOCK_GROUP_RAID6) {
3853                 raid_stripe_len = find_raid56_stripe_len(ndevs - 2,
3854                                  btrfs_super_stripesize(info->super_copy));
3855                 data_stripes = num_stripes - 2;
3856         }
3857
3858         /*
3859          * Use the number of data stripes to figure out how big this chunk
3860          * is really going to be in terms of logical address space,
3861          * and compare that answer with the max chunk size
3862          */
3863         if (stripe_size * data_stripes > max_chunk_size) {
3864                 u64 mask = (1ULL << 24) - 1;
3865                 stripe_size = max_chunk_size;
3866                 do_div(stripe_size, data_stripes);
3867
3868                 /* bump the answer up to a 16MB boundary */
3869                 stripe_size = (stripe_size + mask) & ~mask;
3870
3871                 /* but don't go higher than the limits we found
3872                  * while searching for free extents
3873                  */
3874                 if (stripe_size > devices_info[ndevs-1].max_avail)
3875                         stripe_size = devices_info[ndevs-1].max_avail;
3876         }
3877
3878         do_div(stripe_size, dev_stripes);
3879
3880         /* align to BTRFS_STRIPE_LEN */
3881         do_div(stripe_size, raid_stripe_len);
3882         stripe_size *= raid_stripe_len;
3883
3884         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
3885         if (!map) {
3886                 ret = -ENOMEM;
3887                 goto error;
3888         }
3889         map->num_stripes = num_stripes;
3890
3891         for (i = 0; i < ndevs; ++i) {
3892                 for (j = 0; j < dev_stripes; ++j) {
3893                         int s = i * dev_stripes + j;
3894                         map->stripes[s].dev = devices_info[i].dev;
3895                         map->stripes[s].physical = devices_info[i].dev_offset +
3896                                                    j * stripe_size;
3897                 }
3898         }
3899         map->sector_size = extent_root->sectorsize;
3900         map->stripe_len = raid_stripe_len;
3901         map->io_align = raid_stripe_len;
3902         map->io_width = raid_stripe_len;
3903         map->type = type;
3904         map->sub_stripes = sub_stripes;
3905
3906         *map_ret = map;
3907         num_bytes = stripe_size * data_stripes;
3908
3909         *stripe_size_out = stripe_size;
3910         *num_bytes_out = num_bytes;
3911
3912         trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
3913
3914         em = alloc_extent_map();
3915         if (!em) {
3916                 ret = -ENOMEM;
3917                 goto error;
3918         }
3919         em->bdev = (struct block_device *)map;
3920         em->start = start;
3921         em->len = num_bytes;
3922         em->block_start = 0;
3923         em->block_len = em->len;
3924
3925         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
3926         write_lock(&em_tree->lock);
3927         ret = add_extent_mapping(em_tree, em, 0);
3928         write_unlock(&em_tree->lock);
3929         if (ret) {
3930                 free_extent_map(em);
3931                 goto error;
3932         }
3933
3934         for (i = 0; i < map->num_stripes; ++i) {
3935                 struct btrfs_device *device;
3936                 u64 dev_offset;
3937
3938                 device = map->stripes[i].dev;
3939                 dev_offset = map->stripes[i].physical;
3940
3941                 ret = btrfs_alloc_dev_extent(trans, device,
3942                                 info->chunk_root->root_key.objectid,
3943                                 BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3944                                 start, dev_offset, stripe_size);
3945                 if (ret)
3946                         goto error_dev_extent;
3947         }
3948
3949         ret = btrfs_make_block_group(trans, extent_root, 0, type,
3950                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3951                                      start, num_bytes);
3952         if (ret) {
3953                 i = map->num_stripes - 1;
3954                 goto error_dev_extent;
3955         }
3956
3957         free_extent_map(em);
3958         check_raid56_incompat_flag(extent_root->fs_info, type);
3959
3960         kfree(devices_info);
3961         return 0;
3962
3963 error_dev_extent:
3964         for (; i >= 0; i--) {
3965                 struct btrfs_device *device;
3966                 int err;
3967
3968                 device = map->stripes[i].dev;
3969                 err = btrfs_free_dev_extent(trans, device, start);
3970                 if (err) {
3971                         btrfs_abort_transaction(trans, extent_root, err);
3972                         break;
3973                 }
3974         }
3975         write_lock(&em_tree->lock);
3976         remove_extent_mapping(em_tree, em);
3977         write_unlock(&em_tree->lock);
3978
3979         /* One for our allocation */
3980         free_extent_map(em);
3981         /* One for the tree reference */
3982         free_extent_map(em);
3983 error:
3984         kfree(map);
3985         kfree(devices_info);
3986         return ret;
3987 }
3988
3989 static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
3990                                 struct btrfs_root *extent_root,
3991                                 struct map_lookup *map, u64 chunk_offset,
3992                                 u64 chunk_size, u64 stripe_size)
3993 {
3994         u64 dev_offset;
3995         struct btrfs_key key;
3996         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
3997         struct btrfs_device *device;
3998         struct btrfs_chunk *chunk;
3999         struct btrfs_stripe *stripe;
4000         size_t item_size = btrfs_chunk_item_size(map->num_stripes);
4001         int index = 0;
4002         int ret;
4003
4004         chunk = kzalloc(item_size, GFP_NOFS);
4005         if (!chunk)
4006                 return -ENOMEM;
4007
4008         index = 0;
4009         while (index < map->num_stripes) {
4010                 device = map->stripes[index].dev;
4011                 device->bytes_used += stripe_size;
4012                 ret = btrfs_update_device(trans, device);
4013                 if (ret)
4014                         goto out_free;
4015                 index++;
4016         }
4017
4018         spin_lock(&extent_root->fs_info->free_chunk_lock);
4019         extent_root->fs_info->free_chunk_space -= (stripe_size *
4020                                                    map->num_stripes);
4021         spin_unlock(&extent_root->fs_info->free_chunk_lock);
4022
4023         index = 0;
4024         stripe = &chunk->stripe;
4025         while (index < map->num_stripes) {
4026                 device = map->stripes[index].dev;
4027                 dev_offset = map->stripes[index].physical;
4028
4029                 btrfs_set_stack_stripe_devid(stripe, device->devid);
4030                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
4031                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
4032                 stripe++;
4033                 index++;
4034         }
4035
4036         btrfs_set_stack_chunk_length(chunk, chunk_size);
4037         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
4038         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
4039         btrfs_set_stack_chunk_type(chunk, map->type);
4040         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
4041         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
4042         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
4043         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
4044         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
4045
4046         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
4047         key.type = BTRFS_CHUNK_ITEM_KEY;
4048         key.offset = chunk_offset;
4049
4050         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
4051
4052         if (ret == 0 && map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
4053                 /*
4054                  * TODO: Cleanup of inserted chunk root in case of
4055                  * failure.
4056                  */
4057                 ret = btrfs_add_system_chunk(chunk_root, &key, chunk,
4058                                              item_size);
4059         }
4060
4061 out_free:
4062         kfree(chunk);
4063         return ret;
4064 }
4065
4066 /*
4067  * Chunk allocation falls into two parts. The first part does works
4068  * that make the new allocated chunk useable, but not do any operation
4069  * that modifies the chunk tree. The second part does the works that
4070  * require modifying the chunk tree. This division is important for the
4071  * bootstrap process of adding storage to a seed btrfs.
4072  */
4073 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
4074                       struct btrfs_root *extent_root, u64 type)
4075 {
4076         u64 chunk_offset;
4077         u64 chunk_size;
4078         u64 stripe_size;
4079         struct map_lookup *map;
4080         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
4081         int ret;
4082
4083         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
4084                               &chunk_offset);
4085         if (ret)
4086                 return ret;
4087
4088         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
4089                                   &stripe_size, chunk_offset, type);
4090         if (ret)
4091                 return ret;
4092
4093         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
4094                                    chunk_size, stripe_size);
4095         if (ret)
4096                 return ret;
4097         return 0;
4098 }
4099
4100 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
4101                                          struct btrfs_root *root,
4102                                          struct btrfs_device *device)
4103 {
4104         u64 chunk_offset;
4105         u64 sys_chunk_offset;
4106         u64 chunk_size;
4107         u64 sys_chunk_size;
4108         u64 stripe_size;
4109         u64 sys_stripe_size;
4110         u64 alloc_profile;
4111         struct map_lookup *map;
4112         struct map_lookup *sys_map;
4113         struct btrfs_fs_info *fs_info = root->fs_info;
4114         struct btrfs_root *extent_root = fs_info->extent_root;
4115         int ret;
4116
4117         ret = find_next_chunk(fs_info->chunk_root,
4118                               BTRFS_FIRST_CHUNK_TREE_OBJECTID, &chunk_offset);
4119         if (ret)
4120                 return ret;
4121
4122         alloc_profile = btrfs_get_alloc_profile(extent_root, 0);
4123         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
4124                                   &stripe_size, chunk_offset, alloc_profile);
4125         if (ret)
4126                 return ret;
4127
4128         sys_chunk_offset = chunk_offset + chunk_size;
4129
4130         alloc_profile = btrfs_get_alloc_profile(fs_info->chunk_root, 0);
4131         ret = __btrfs_alloc_chunk(trans, extent_root, &sys_map,
4132                                   &sys_chunk_size, &sys_stripe_size,
4133                                   sys_chunk_offset, alloc_profile);
4134         if (ret) {
4135                 btrfs_abort_transaction(trans, root, ret);
4136                 goto out;
4137         }
4138
4139         ret = btrfs_add_device(trans, fs_info->chunk_root, device);
4140         if (ret) {
4141                 btrfs_abort_transaction(trans, root, ret);
4142                 goto out;
4143         }
4144
4145         /*
4146          * Modifying chunk tree needs allocating new blocks from both
4147          * system block group and metadata block group. So we only can
4148          * do operations require modifying the chunk tree after both
4149          * block groups were created.
4150          */
4151         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
4152                                    chunk_size, stripe_size);
4153         if (ret) {
4154                 btrfs_abort_transaction(trans, root, ret);
4155                 goto out;
4156         }
4157
4158         ret = __finish_chunk_alloc(trans, extent_root, sys_map,
4159                                    sys_chunk_offset, sys_chunk_size,
4160                                    sys_stripe_size);
4161         if (ret)
4162                 btrfs_abort_transaction(trans, root, ret);
4163
4164 out:
4165
4166         return ret;
4167 }
4168
4169 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
4170 {
4171         struct extent_map *em;
4172         struct map_lookup *map;
4173         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
4174         int readonly = 0;
4175         int i;
4176
4177         read_lock(&map_tree->map_tree.lock);
4178         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
4179         read_unlock(&map_tree->map_tree.lock);
4180         if (!em)
4181                 return 1;
4182
4183         if (btrfs_test_opt(root, DEGRADED)) {
4184                 free_extent_map(em);
4185                 return 0;
4186         }
4187
4188         map = (struct map_lookup *)em->bdev;
4189         for (i = 0; i < map->num_stripes; i++) {
4190                 if (!map->stripes[i].dev->writeable) {
4191                         readonly = 1;
4192                         break;
4193                 }
4194         }
4195         free_extent_map(em);
4196         return readonly;
4197 }
4198
4199 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
4200 {
4201         extent_map_tree_init(&tree->map_tree);
4202 }
4203
4204 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
4205 {
4206         struct extent_map *em;
4207
4208         while (1) {
4209                 write_lock(&tree->map_tree.lock);
4210                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
4211                 if (em)
4212                         remove_extent_mapping(&tree->map_tree, em);
4213                 write_unlock(&tree->map_tree.lock);
4214                 if (!em)
4215                         break;
4216                 kfree(em->bdev);
4217                 /* once for us */
4218                 free_extent_map(em);
4219                 /* once for the tree */
4220                 free_extent_map(em);
4221         }
4222 }
4223
4224 int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
4225 {
4226         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
4227         struct extent_map *em;
4228         struct map_lookup *map;
4229         struct extent_map_tree *em_tree = &map_tree->map_tree;
4230         int ret;
4231
4232         read_lock(&em_tree->lock);
4233         em = lookup_extent_mapping(em_tree, logical, len);
4234         read_unlock(&em_tree->lock);
4235
4236         /*
4237          * We could return errors for these cases, but that could get ugly and
4238          * we'd probably do the same thing which is just not do anything else
4239          * and exit, so return 1 so the callers don't try to use other copies.
4240          */
4241         if (!em) {
4242                 btrfs_emerg(fs_info, "No mapping for %Lu-%Lu\n", logical,
4243                             logical+len);
4244                 return 1;
4245         }
4246
4247         if (em->start > logical || em->start + em->len < logical) {
4248                 btrfs_emerg(fs_info, "Invalid mapping for %Lu-%Lu, got "
4249                             "%Lu-%Lu\n", logical, logical+len, em->start,
4250                             em->start + em->len);
4251                 return 1;
4252         }
4253
4254         map = (struct map_lookup *)em->bdev;
4255         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
4256                 ret = map->num_stripes;
4257         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
4258                 ret = map->sub_stripes;
4259         else if (map->type & BTRFS_BLOCK_GROUP_RAID5)
4260                 ret = 2;
4261         else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
4262                 ret = 3;
4263         else
4264                 ret = 1;
4265         free_extent_map(em);
4266
4267         btrfs_dev_replace_lock(&fs_info->dev_replace);
4268         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))
4269                 ret++;
4270         btrfs_dev_replace_unlock(&fs_info->dev_replace);
4271
4272         return ret;
4273 }
4274
4275 unsigned long btrfs_full_stripe_len(struct btrfs_root *root,
4276                                     struct btrfs_mapping_tree *map_tree,
4277                                     u64 logical)
4278 {
4279         struct extent_map *em;
4280         struct map_lookup *map;
4281         struct extent_map_tree *em_tree = &map_tree->map_tree;
4282         unsigned long len = root->sectorsize;
4283
4284         read_lock(&em_tree->lock);
4285         em = lookup_extent_mapping(em_tree, logical, len);
4286         read_unlock(&em_tree->lock);
4287         BUG_ON(!em);
4288
4289         BUG_ON(em->start > logical || em->start + em->len < logical);
4290         map = (struct map_lookup *)em->bdev;
4291         if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
4292                          BTRFS_BLOCK_GROUP_RAID6)) {
4293                 len = map->stripe_len * nr_data_stripes(map);
4294         }
4295         free_extent_map(em);
4296         return len;
4297 }
4298
4299 int btrfs_is_parity_mirror(struct btrfs_mapping_tree *map_tree,
4300                            u64 logical, u64 len, int mirror_num)
4301 {
4302         struct extent_map *em;
4303         struct map_lookup *map;
4304         struct extent_map_tree *em_tree = &map_tree->map_tree;
4305         int ret = 0;
4306
4307         read_lock(&em_tree->lock);
4308         em = lookup_extent_mapping(em_tree, logical, len);
4309         read_unlock(&em_tree->lock);
4310         BUG_ON(!em);
4311
4312         BUG_ON(em->start > logical || em->start + em->len < logical);
4313         map = (struct map_lookup *)em->bdev;
4314         if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
4315                          BTRFS_BLOCK_GROUP_RAID6))
4316                 ret = 1;
4317         free_extent_map(em);
4318         return ret;
4319 }
4320
4321 static int find_live_mirror(struct btrfs_fs_info *fs_info,
4322                             struct map_lookup *map, int first, int num,
4323                             int optimal, int dev_replace_is_ongoing)
4324 {
4325         int i;
4326         int tolerance;
4327         struct btrfs_device *srcdev;
4328
4329         if (dev_replace_is_ongoing &&
4330             fs_info->dev_replace.cont_reading_from_srcdev_mode ==
4331              BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID)
4332                 srcdev = fs_info->dev_replace.srcdev;
4333         else
4334                 srcdev = NULL;
4335
4336         /*
4337          * try to avoid the drive that is the source drive for a
4338          * dev-replace procedure, only choose it if no other non-missing
4339          * mirror is available
4340          */
4341         for (tolerance = 0; tolerance < 2; tolerance++) {
4342                 if (map->stripes[optimal].dev->bdev &&
4343                     (tolerance || map->stripes[optimal].dev != srcdev))
4344                         return optimal;
4345                 for (i = first; i < first + num; i++) {
4346                         if (map->stripes[i].dev->bdev &&
4347                             (tolerance || map->stripes[i].dev != srcdev))
4348                                 return i;
4349                 }
4350         }
4351
4352         /* we couldn't find one that doesn't fail.  Just return something
4353          * and the io error handling code will clean up eventually
4354          */
4355         return optimal;
4356 }
4357
4358 static inline int parity_smaller(u64 a, u64 b)
4359 {
4360         return a > b;
4361 }
4362
4363 /* Bubble-sort the stripe set to put the parity/syndrome stripes last */
4364 static void sort_parity_stripes(struct btrfs_bio *bbio, u64 *raid_map)
4365 {
4366         struct btrfs_bio_stripe s;
4367         int i;
4368         u64 l;
4369         int again = 1;
4370
4371         while (again) {
4372                 again = 0;
4373                 for (i = 0; i < bbio->num_stripes - 1; i++) {
4374                         if (parity_smaller(raid_map[i], raid_map[i+1])) {
4375                                 s = bbio->stripes[i];
4376                                 l = raid_map[i];
4377                                 bbio->stripes[i] = bbio->stripes[i+1];
4378                                 raid_map[i] = raid_map[i+1];
4379                                 bbio->stripes[i+1] = s;
4380                                 raid_map[i+1] = l;
4381                                 again = 1;
4382                         }
4383                 }
4384         }
4385 }
4386
4387 static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
4388                              u64 logical, u64 *length,
4389                              struct btrfs_bio **bbio_ret,
4390                              int mirror_num, u64 **raid_map_ret)
4391 {
4392         struct extent_map *em;
4393         struct map_lookup *map;
4394         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
4395         struct extent_map_tree *em_tree = &map_tree->map_tree;
4396         u64 offset;
4397         u64 stripe_offset;
4398         u64 stripe_end_offset;
4399         u64 stripe_nr;
4400         u64 stripe_nr_orig;
4401         u64 stripe_nr_end;
4402         u64 stripe_len;
4403         u64 *raid_map = NULL;
4404         int stripe_index;
4405         int i;
4406         int ret = 0;
4407         int num_stripes;
4408         int max_errors = 0;
4409         struct btrfs_bio *bbio = NULL;
4410         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
4411         int dev_replace_is_ongoing = 0;
4412         int num_alloc_stripes;
4413         int patch_the_first_stripe_for_dev_replace = 0;
4414         u64 physical_to_patch_in_first_stripe = 0;
4415         u64 raid56_full_stripe_start = (u64)-1;
4416
4417         read_lock(&em_tree->lock);
4418         em = lookup_extent_mapping(em_tree, logical, *length);
4419         read_unlock(&em_tree->lock);
4420
4421         if (!em) {
4422                 btrfs_crit(fs_info, "unable to find logical %llu len %llu",
4423                         (unsigned long long)logical,
4424                         (unsigned long long)*length);
4425                 return -EINVAL;
4426         }
4427
4428         if (em->start > logical || em->start + em->len < logical) {
4429                 btrfs_crit(fs_info, "found a bad mapping, wanted %Lu, "
4430                            "found %Lu-%Lu\n", logical, em->start,
4431                            em->start + em->len);
4432                 return -EINVAL;
4433         }
4434
4435         map = (struct map_lookup *)em->bdev;
4436         offset = logical - em->start;
4437
4438         if (mirror_num > map->num_stripes)
4439                 mirror_num = 0;
4440
4441         stripe_len = map->stripe_len;
4442         stripe_nr = offset;
4443         /*
4444          * stripe_nr counts the total number of stripes we have to stride
4445          * to get to this block
4446          */
4447         do_div(stripe_nr, stripe_len);
4448
4449         stripe_offset = stripe_nr * stripe_len;
4450         BUG_ON(offset < stripe_offset);
4451
4452         /* stripe_offset is the offset of this block in its stripe*/
4453         stripe_offset = offset - stripe_offset;
4454
4455         /* if we're here for raid56, we need to know the stripe aligned start */
4456         if (map->type & (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6)) {
4457                 unsigned long full_stripe_len = stripe_len * nr_data_stripes(map);
4458                 raid56_full_stripe_start = offset;
4459
4460                 /* allow a write of a full stripe, but make sure we don't
4461                  * allow straddling of stripes
4462                  */
4463                 do_div(raid56_full_stripe_start, full_stripe_len);
4464                 raid56_full_stripe_start *= full_stripe_len;
4465         }
4466
4467         if (rw & REQ_DISCARD) {
4468                 /* we don't discard raid56 yet */
4469                 if (map->type &
4470                     (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6)) {
4471                         ret = -EOPNOTSUPP;
4472                         goto out;
4473                 }
4474                 *length = min_t(u64, em->len - offset, *length);
4475         } else if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
4476                 u64 max_len;
4477                 /* For writes to RAID[56], allow a full stripeset across all disks.
4478                    For other RAID types and for RAID[56] reads, just allow a single
4479                    stripe (on a single disk). */
4480                 if (map->type & (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6) &&
4481                     (rw & REQ_WRITE)) {
4482                         max_len = stripe_len * nr_data_stripes(map) -
4483                                 (offset - raid56_full_stripe_start);
4484                 } else {
4485                         /* we limit the length of each bio to what fits in a stripe */
4486                         max_len = stripe_len - stripe_offset;
4487                 }
4488                 *length = min_t(u64, em->len - offset, max_len);
4489         } else {
4490                 *length = em->len - offset;
4491         }
4492
4493         /* This is for when we're called from btrfs_merge_bio_hook() and all
4494            it cares about is the length */
4495         if (!bbio_ret)
4496                 goto out;
4497
4498         btrfs_dev_replace_lock(dev_replace);
4499         dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(dev_replace);
4500         if (!dev_replace_is_ongoing)
4501                 btrfs_dev_replace_unlock(dev_replace);
4502
4503         if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 &&
4504             !(rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) &&
4505             dev_replace->tgtdev != NULL) {
4506                 /*
4507                  * in dev-replace case, for repair case (that's the only
4508                  * case where the mirror is selected explicitly when
4509                  * calling btrfs_map_block), blocks left of the left cursor
4510                  * can also be read from the target drive.
4511                  * For REQ_GET_READ_MIRRORS, the target drive is added as
4512                  * the last one to the array of stripes. For READ, it also
4513                  * needs to be supported using the same mirror number.
4514                  * If the requested block is not left of the left cursor,
4515                  * EIO is returned. This can happen because btrfs_num_copies()
4516                  * returns one more in the dev-replace case.
4517                  */
4518                 u64 tmp_length = *length;
4519                 struct btrfs_bio *tmp_bbio = NULL;
4520                 int tmp_num_stripes;
4521                 u64 srcdev_devid = dev_replace->srcdev->devid;
4522                 int index_srcdev = 0;
4523                 int found = 0;
4524                 u64 physical_of_found = 0;
4525
4526                 ret = __btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS,
4527                              logical, &tmp_length, &tmp_bbio, 0, NULL);
4528                 if (ret) {
4529                         WARN_ON(tmp_bbio != NULL);
4530                         goto out;
4531                 }
4532
4533                 tmp_num_stripes = tmp_bbio->num_stripes;
4534                 if (mirror_num > tmp_num_stripes) {
4535                         /*
4536                          * REQ_GET_READ_MIRRORS does not contain this
4537                          * mirror, that means that the requested area
4538                          * is not left of the left cursor
4539                          */
4540                         ret = -EIO;
4541                         kfree(tmp_bbio);
4542                         goto out;
4543                 }
4544
4545                 /*
4546                  * process the rest of the function using the mirror_num
4547                  * of the source drive. Therefore look it up first.
4548                  * At the end, patch the device pointer to the one of the
4549                  * target drive.
4550                  */
4551                 for (i = 0; i < tmp_num_stripes; i++) {
4552                         if (tmp_bbio->stripes[i].dev->devid == srcdev_devid) {
4553                                 /*
4554                                  * In case of DUP, in order to keep it
4555                                  * simple, only add the mirror with the
4556                                  * lowest physical address
4557                                  */
4558                                 if (found &&
4559                                     physical_of_found <=
4560                                      tmp_bbio->stripes[i].physical)
4561                                         continue;
4562                                 index_srcdev = i;
4563                                 found = 1;
4564                                 physical_of_found =
4565                                         tmp_bbio->stripes[i].physical;
4566                         }
4567                 }
4568
4569                 if (found) {
4570                         mirror_num = index_srcdev + 1;
4571                         patch_the_first_stripe_for_dev_replace = 1;
4572                         physical_to_patch_in_first_stripe = physical_of_found;
4573                 } else {
4574                         WARN_ON(1);
4575                         ret = -EIO;
4576                         kfree(tmp_bbio);
4577                         goto out;
4578                 }
4579
4580                 kfree(tmp_bbio);
4581         } else if (mirror_num > map->num_stripes) {
4582                 mirror_num = 0;
4583         }
4584
4585         num_stripes = 1;
4586         stripe_index = 0;
4587         stripe_nr_orig = stripe_nr;
4588         stripe_nr_end = ALIGN(offset + *length, map->stripe_len);
4589         do_div(stripe_nr_end, map->stripe_len);
4590         stripe_end_offset = stripe_nr_end * map->stripe_len -
4591                             (offset + *length);
4592
4593         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
4594                 if (rw & REQ_DISCARD)
4595                         num_stripes = min_t(u64, map->num_stripes,
4596                                             stripe_nr_end - stripe_nr_orig);
4597                 stripe_index = do_div(stripe_nr, map->num_stripes);
4598         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
4599                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS))
4600                         num_stripes = map->num_stripes;
4601                 else if (mirror_num)
4602                         stripe_index = mirror_num - 1;
4603                 else {
4604                         stripe_index = find_live_mirror(fs_info, map, 0,
4605                                             map->num_stripes,
4606                                             current->pid % map->num_stripes,
4607                                             dev_replace_is_ongoing);
4608                         mirror_num = stripe_index + 1;
4609                 }
4610
4611         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
4612                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) {
4613                         num_stripes = map->num_stripes;
4614                 } else if (mirror_num) {
4615                         stripe_index = mirror_num - 1;
4616                 } else {
4617                         mirror_num = 1;
4618                 }
4619
4620         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
4621                 int factor = map->num_stripes / map->sub_stripes;
4622
4623                 stripe_index = do_div(stripe_nr, factor);
4624                 stripe_index *= map->sub_stripes;
4625
4626                 if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS))
4627                         num_stripes = map->sub_stripes;
4628                 else if (rw & REQ_DISCARD)
4629                         num_stripes = min_t(u64, map->sub_stripes *
4630                                             (stripe_nr_end - stripe_nr_orig),
4631                                             map->num_stripes);
4632                 else if (mirror_num)
4633                         stripe_index += mirror_num - 1;
4634                 else {
4635                         int old_stripe_index = stripe_index;
4636                         stripe_index = find_live_mirror(fs_info, map,
4637                                               stripe_index,
4638                                               map->sub_stripes, stripe_index +
4639                                               current->pid % map->sub_stripes,
4640                                               dev_replace_is_ongoing);
4641                         mirror_num = stripe_index - old_stripe_index + 1;
4642                 }
4643
4644         } else if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
4645                                 BTRFS_BLOCK_GROUP_RAID6)) {
4646                 u64 tmp;
4647
4648                 if (bbio_ret && ((rw & REQ_WRITE) || mirror_num > 1)
4649                     && raid_map_ret) {
4650                         int i, rot;
4651
4652                         /* push stripe_nr back to the start of the full stripe */
4653                         stripe_nr = raid56_full_stripe_start;
4654                         do_div(stripe_nr, stripe_len);
4655
4656                         stripe_index = do_div(stripe_nr, nr_data_stripes(map));
4657
4658                         /* RAID[56] write or recovery. Return all stripes */
4659                         num_stripes = map->num_stripes;
4660                         max_errors = nr_parity_stripes(map);
4661
4662                         raid_map = kmalloc(sizeof(u64) * num_stripes,
4663                                            GFP_NOFS);
4664                         if (!raid_map) {
4665                                 ret = -ENOMEM;
4666                                 goto out;
4667                         }
4668
4669                         /* Work out the disk rotation on this stripe-set */
4670                         tmp = stripe_nr;
4671                         rot = do_div(tmp, num_stripes);
4672
4673                         /* Fill in the logical address of each stripe */
4674                         tmp = stripe_nr * nr_data_stripes(map);
4675                         for (i = 0; i < nr_data_stripes(map); i++)
4676                                 raid_map[(i+rot) % num_stripes] =
4677                                         em->start + (tmp + i) * map->stripe_len;
4678
4679                         raid_map[(i+rot) % map->num_stripes] = RAID5_P_STRIPE;
4680                         if (map->type & BTRFS_BLOCK_GROUP_RAID6)
4681                                 raid_map[(i+rot+1) % num_stripes] =
4682                                         RAID6_Q_STRIPE;
4683
4684                         *length = map->stripe_len;
4685                         stripe_index = 0;
4686                         stripe_offset = 0;
4687                 } else {
4688                         /*
4689                          * Mirror #0 or #1 means the original data block.
4690                          * Mirror #2 is RAID5 parity block.
4691                          * Mirror #3 is RAID6 Q block.
4692                          */
4693                         stripe_index = do_div(stripe_nr, nr_data_stripes(map));
4694                         if (mirror_num > 1)
4695                                 stripe_index = nr_data_stripes(map) +
4696                                                 mirror_num - 2;
4697
4698                         /* We distribute the parity blocks across stripes */
4699                         tmp = stripe_nr + stripe_index;
4700                         stripe_index = do_div(tmp, map->num_stripes);
4701                 }
4702         } else {
4703                 /*
4704                  * after this do_div call, stripe_nr is the number of stripes
4705                  * on this device we have to walk to find the data, and
4706                  * stripe_index is the number of our device in the stripe array
4707                  */
4708                 stripe_index = do_div(stripe_nr, map->num_stripes);
4709                 mirror_num = stripe_index + 1;
4710         }
4711         BUG_ON(stripe_index >= map->num_stripes);
4712
4713         num_alloc_stripes = num_stripes;
4714         if (dev_replace_is_ongoing) {
4715                 if (rw & (REQ_WRITE | REQ_DISCARD))
4716                         num_alloc_stripes <<= 1;
4717                 if (rw & REQ_GET_READ_MIRRORS)
4718                         num_alloc_stripes++;
4719         }
4720         bbio = kzalloc(btrfs_bio_size(num_alloc_stripes), GFP_NOFS);
4721         if (!bbio) {
4722                 ret = -ENOMEM;
4723                 goto out;
4724         }
4725         atomic_set(&bbio->error, 0);
4726
4727         if (rw & REQ_DISCARD) {
4728                 int factor = 0;
4729                 int sub_stripes = 0;
4730                 u64 stripes_per_dev = 0;
4731                 u32 remaining_stripes = 0;
4732                 u32 last_stripe = 0;
4733
4734                 if (map->type &
4735                     (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
4736                         if (map->type & BTRFS_BLOCK_GROUP_RAID0)
4737                                 sub_stripes = 1;
4738                         else
4739                                 sub_stripes = map->sub_stripes;
4740
4741                         factor = map->num_stripes / sub_stripes;
4742                         stripes_per_dev = div_u64_rem(stripe_nr_end -
4743                                                       stripe_nr_orig,
4744                                                       factor,
4745                                                       &remaining_stripes);
4746                         div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
4747                         last_stripe *= sub_stripes;
4748                 }
4749
4750                 for (i = 0; i < num_stripes; i++) {
4751                         bbio->stripes[i].physical =
4752                                 map->stripes[stripe_index].physical +
4753                                 stripe_offset + stripe_nr * map->stripe_len;
4754                         bbio->stripes[i].dev = map->stripes[stripe_index].dev;
4755
4756                         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
4757                                          BTRFS_BLOCK_GROUP_RAID10)) {
4758                                 bbio->stripes[i].length = stripes_per_dev *
4759                                                           map->stripe_len;
4760
4761                                 if (i / sub_stripes < remaining_stripes)
4762                                         bbio->stripes[i].length +=
4763                                                 map->stripe_len;
4764
4765                                 /*
4766                                  * Special for the first stripe and
4767                                  * the last stripe:
4768                                  *
4769                                  * |-------|...|-------|
4770                                  *     |----------|
4771                                  *    off     end_off
4772                                  */
4773                                 if (i < sub_stripes)
4774                                         bbio->stripes[i].length -=
4775                                                 stripe_offset;
4776
4777                                 if (stripe_index >= last_stripe &&
4778                                     stripe_index <= (last_stripe +
4779                                                      sub_stripes - 1))
4780                                         bbio->stripes[i].length -=
4781                                                 stripe_end_offset;
4782
4783                                 if (i == sub_stripes - 1)
4784                                         stripe_offset = 0;
4785                         } else
4786                                 bbio->stripes[i].length = *length;
4787
4788                         stripe_index++;
4789                         if (stripe_index == map->num_stripes) {
4790                                 /* This could only happen for RAID0/10 */
4791                                 stripe_index = 0;
4792                                 stripe_nr++;
4793                         }
4794                 }
4795         } else {
4796                 for (i = 0; i < num_stripes; i++) {
4797                         bbio->stripes[i].physical =
4798                                 map->stripes[stripe_index].physical +
4799                                 stripe_offset +
4800                                 stripe_nr * map->stripe_len;
4801                         bbio->stripes[i].dev =
4802                                 map->stripes[stripe_index].dev;
4803                         stripe_index++;
4804                 }
4805         }
4806
4807         if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS)) {
4808                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
4809                                  BTRFS_BLOCK_GROUP_RAID10 |
4810                                  BTRFS_BLOCK_GROUP_RAID5 |
4811                                  BTRFS_BLOCK_GROUP_DUP)) {
4812                         max_errors = 1;
4813                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID6) {
4814                         max_errors = 2;
4815                 }
4816         }
4817
4818         if (dev_replace_is_ongoing && (rw & (REQ_WRITE | REQ_DISCARD)) &&
4819             dev_replace->tgtdev != NULL) {
4820                 int index_where_to_add;
4821                 u64 srcdev_devid = dev_replace->srcdev->devid;
4822
4823                 /*
4824                  * duplicate the write operations while the dev replace
4825                  * procedure is running. Since the copying of the old disk
4826                  * to the new disk takes place at run time while the
4827                  * filesystem is mounted writable, the regular write
4828                  * operations to the old disk have to be duplicated to go
4829                  * to the new disk as well.
4830                  * Note that device->missing is handled by the caller, and
4831                  * that the write to the old disk is already set up in the
4832                  * stripes array.
4833                  */
4834                 index_where_to_add = num_stripes;
4835                 for (i = 0; i < num_stripes; i++) {
4836                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
4837                                 /* write to new disk, too */
4838                                 struct btrfs_bio_stripe *new =
4839                                         bbio->stripes + index_where_to_add;
4840                                 struct btrfs_bio_stripe *old =
4841                                         bbio->stripes + i;
4842
4843                                 new->physical = old->physical;
4844                                 new->length = old->length;
4845                                 new->dev = dev_replace->tgtdev;
4846                                 index_where_to_add++;
4847                                 max_errors++;
4848                         }
4849                 }
4850                 num_stripes = index_where_to_add;
4851         } else if (dev_replace_is_ongoing && (rw & REQ_GET_READ_MIRRORS) &&
4852                    dev_replace->tgtdev != NULL) {
4853                 u64 srcdev_devid = dev_replace->srcdev->devid;
4854                 int index_srcdev = 0;
4855                 int found = 0;
4856                 u64 physical_of_found = 0;
4857
4858                 /*
4859                  * During the dev-replace procedure, the target drive can
4860                  * also be used to read data in case it is needed to repair
4861                  * a corrupt block elsewhere. This is possible if the
4862                  * requested area is left of the left cursor. In this area,
4863                  * the target drive is a full copy of the source drive.
4864                  */
4865                 for (i = 0; i < num_stripes; i++) {
4866                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
4867                                 /*
4868                                  * In case of DUP, in order to keep it
4869                                  * simple, only add the mirror with the
4870                                  * lowest physical address
4871                                  */
4872                                 if (found &&
4873                                     physical_of_found <=
4874                                      bbio->stripes[i].physical)
4875                                         continue;
4876                                 index_srcdev = i;
4877                                 found = 1;
4878                                 physical_of_found = bbio->stripes[i].physical;
4879                         }
4880                 }
4881                 if (found) {
4882                         u64 length = map->stripe_len;
4883
4884                         if (physical_of_found + length <=
4885                             dev_replace->cursor_left) {
4886                                 struct btrfs_bio_stripe *tgtdev_stripe =
4887                                         bbio->stripes + num_stripes;
4888
4889                                 tgtdev_stripe->physical = physical_of_found;
4890                                 tgtdev_stripe->length =
4891                                         bbio->stripes[index_srcdev].length;
4892                                 tgtdev_stripe->dev = dev_replace->tgtdev;
4893
4894                                 num_stripes++;
4895                         }
4896                 }
4897         }
4898
4899         *bbio_ret = bbio;
4900         bbio->num_stripes = num_stripes;
4901         bbio->max_errors = max_errors;
4902         bbio->mirror_num = mirror_num;
4903
4904         /*
4905          * this is the case that REQ_READ && dev_replace_is_ongoing &&
4906          * mirror_num == num_stripes + 1 && dev_replace target drive is
4907          * available as a mirror
4908          */
4909         if (patch_the_first_stripe_for_dev_replace && num_stripes > 0) {
4910                 WARN_ON(num_stripes > 1);
4911                 bbio->stripes[0].dev = dev_replace->tgtdev;
4912                 bbio->stripes[0].physical = physical_to_patch_in_first_stripe;
4913                 bbio->mirror_num = map->num_stripes + 1;
4914         }
4915         if (raid_map) {
4916                 sort_parity_stripes(bbio, raid_map);
4917                 *raid_map_ret = raid_map;
4918         }
4919 out:
4920         if (dev_replace_is_ongoing)
4921                 btrfs_dev_replace_unlock(dev_replace);
4922         free_extent_map(em);
4923         return ret;
4924 }
4925
4926 int btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
4927                       u64 logical, u64 *length,
4928                       struct btrfs_bio **bbio_ret, int mirror_num)
4929 {
4930         return __btrfs_map_block(fs_info, rw, logical, length, bbio_ret,
4931                                  mirror_num, NULL);
4932 }
4933
4934 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
4935                      u64 chunk_start, u64 physical, u64 devid,
4936                      u64 **logical, int *naddrs, int *stripe_len)
4937 {
4938         struct extent_map_tree *em_tree = &map_tree->map_tree;
4939         struct extent_map *em;
4940         struct map_lookup *map;
4941         u64 *buf;
4942         u64 bytenr;
4943         u64 length;
4944         u64 stripe_nr;
4945         u64 rmap_len;
4946         int i, j, nr = 0;
4947
4948         read_lock(&em_tree->lock);
4949         em = lookup_extent_mapping(em_tree, chunk_start, 1);
4950         read_unlock(&em_tree->lock);
4951
4952         if (!em) {
4953                 printk(KERN_ERR "btrfs: couldn't find em for chunk %Lu\n",
4954                        chunk_start);
4955                 return -EIO;
4956         }
4957
4958         if (em->start != chunk_start) {
4959                 printk(KERN_ERR "btrfs: bad chunk start, em=%Lu, wanted=%Lu\n",
4960                        em->start, chunk_start);
4961                 free_extent_map(em);
4962                 return -EIO;
4963         }
4964         map = (struct map_lookup *)em->bdev;
4965
4966         length = em->len;
4967         rmap_len = map->stripe_len;
4968
4969         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
4970                 do_div(length, map->num_stripes / map->sub_stripes);
4971         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
4972                 do_div(length, map->num_stripes);
4973         else if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
4974                               BTRFS_BLOCK_GROUP_RAID6)) {
4975                 do_div(length, nr_data_stripes(map));
4976                 rmap_len = map->stripe_len * nr_data_stripes(map);
4977         }
4978
4979         buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
4980         BUG_ON(!buf); /* -ENOMEM */
4981
4982         for (i = 0; i < map->num_stripes; i++) {
4983                 if (devid && map->stripes[i].dev->devid != devid)
4984                         continue;
4985                 if (map->stripes[i].physical > physical ||
4986                     map->stripes[i].physical + length <= physical)
4987                         continue;
4988
4989                 stripe_nr = physical - map->stripes[i].physical;
4990                 do_div(stripe_nr, map->stripe_len);
4991
4992                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
4993                         stripe_nr = stripe_nr * map->num_stripes + i;
4994                         do_div(stripe_nr, map->sub_stripes);
4995                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
4996                         stripe_nr = stripe_nr * map->num_stripes + i;
4997                 } /* else if RAID[56], multiply by nr_data_stripes().
4998                    * Alternatively, just use rmap_len below instead of
4999                    * map->stripe_len */
5000
5001                 bytenr = chunk_start + stripe_nr * rmap_len;
5002                 WARN_ON(nr >= map->num_stripes);
5003                 for (j = 0; j < nr; j++) {
5004                         if (buf[j] == bytenr)
5005                                 break;
5006                 }
5007                 if (j == nr) {
5008                         WARN_ON(nr >= map->num_stripes);
5009                         buf[nr++] = bytenr;
5010                 }
5011         }
5012
5013         *logical = buf;
5014         *naddrs = nr;
5015         *stripe_len = rmap_len;
5016
5017         free_extent_map(em);
5018         return 0;
5019 }
5020
5021 static void btrfs_end_bio(struct bio *bio, int err)
5022 {
5023         struct btrfs_bio *bbio = bio->bi_private;
5024         int is_orig_bio = 0;
5025
5026         if (err) {
5027                 atomic_inc(&bbio->error);
5028                 if (err == -EIO || err == -EREMOTEIO) {
5029                         unsigned int stripe_index =
5030                                 btrfs_io_bio(bio)->stripe_index;
5031                         struct btrfs_device *dev;
5032
5033                         BUG_ON(stripe_index >= bbio->num_stripes);
5034                         dev = bbio->stripes[stripe_index].dev;
5035                         if (dev->bdev) {
5036                                 if (bio->bi_rw & WRITE)
5037                                         btrfs_dev_stat_inc(dev,
5038                                                 BTRFS_DEV_STAT_WRITE_ERRS);
5039                                 else
5040                                         btrfs_dev_stat_inc(dev,
5041                                                 BTRFS_DEV_STAT_READ_ERRS);
5042                                 if ((bio->bi_rw & WRITE_FLUSH) == WRITE_FLUSH)
5043                                         btrfs_dev_stat_inc(dev,
5044                                                 BTRFS_DEV_STAT_FLUSH_ERRS);
5045                                 btrfs_dev_stat_print_on_error(dev);
5046                         }
5047                 }
5048         }
5049
5050         if (bio == bbio->orig_bio)
5051                 is_orig_bio = 1;
5052
5053         if (atomic_dec_and_test(&bbio->stripes_pending)) {
5054                 if (!is_orig_bio) {
5055                         bio_put(bio);
5056                         bio = bbio->orig_bio;
5057                 }
5058                 bio->bi_private = bbio->private;
5059                 bio->bi_end_io = bbio->end_io;
5060                 btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
5061                 /* only send an error to the higher layers if it is
5062                  * beyond the tolerance of the btrfs bio
5063                  */
5064                 if (atomic_read(&bbio->error) > bbio->max_errors) {
5065                         err = -EIO;
5066                 } else {
5067                         /*
5068                          * this bio is actually up to date, we didn't
5069                          * go over the max number of errors
5070                          */
5071                         set_bit(BIO_UPTODATE, &bio->bi_flags);
5072                         err = 0;
5073                 }
5074                 kfree(bbio);
5075
5076                 bio_endio(bio, err);
5077         } else if (!is_orig_bio) {
5078                 bio_put(bio);
5079         }
5080 }
5081
5082 struct async_sched {
5083         struct bio *bio;
5084         int rw;
5085         struct btrfs_fs_info *info;
5086         struct btrfs_work work;
5087 };
5088
5089 /*
5090  * see run_scheduled_bios for a description of why bios are collected for
5091  * async submit.
5092  *
5093  * This will add one bio to the pending list for a device and make sure
5094  * the work struct is scheduled.
5095  */
5096 static noinline void btrfs_schedule_bio(struct btrfs_root *root,
5097                                         struct btrfs_device *device,
5098                                         int rw, struct bio *bio)
5099 {
5100         int should_queue = 1;
5101         struct btrfs_pending_bios *pending_bios;
5102
5103         if (device->missing || !device->bdev) {
5104                 bio_endio(bio, -EIO);
5105                 return;
5106         }
5107
5108         /* don't bother with additional async steps for reads, right now */
5109         if (!(rw & REQ_WRITE)) {
5110                 bio_get(bio);
5111                 btrfsic_submit_bio(rw, bio);
5112                 bio_put(bio);
5113                 return;
5114         }
5115
5116         /*
5117          * nr_async_bios allows us to reliably return congestion to the
5118          * higher layers.  Otherwise, the async bio makes it appear we have
5119          * made progress against dirty pages when we've really just put it
5120          * on a queue for later
5121          */
5122         atomic_inc(&root->fs_info->nr_async_bios);
5123         WARN_ON(bio->bi_next);
5124         bio->bi_next = NULL;
5125         bio->bi_rw |= rw;
5126
5127         spin_lock(&device->io_lock);
5128         if (bio->bi_rw & REQ_SYNC)
5129                 pending_bios = &device->pending_sync_bios;
5130         else
5131                 pending_bios = &device->pending_bios;
5132
5133         if (pending_bios->tail)
5134                 pending_bios->tail->bi_next = bio;
5135
5136         pending_bios->tail = bio;
5137         if (!pending_bios->head)
5138                 pending_bios->head = bio;
5139         if (device->running_pending)
5140                 should_queue = 0;
5141
5142         spin_unlock(&device->io_lock);
5143
5144         if (should_queue)
5145                 btrfs_queue_worker(&root->fs_info->submit_workers,
5146                                    &device->work);
5147 }
5148
5149 static int bio_size_ok(struct block_device *bdev, struct bio *bio,
5150                        sector_t sector)
5151 {
5152         struct bio_vec *prev;
5153         struct request_queue *q = bdev_get_queue(bdev);
5154         unsigned short max_sectors = queue_max_sectors(q);
5155         struct bvec_merge_data bvm = {
5156                 .bi_bdev = bdev,
5157                 .bi_sector = sector,
5158                 .bi_rw = bio->bi_rw,
5159         };
5160
5161         if (bio->bi_vcnt == 0) {
5162                 WARN_ON(1);
5163                 return 1;
5164         }
5165
5166         prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
5167         if (bio_sectors(bio) > max_sectors)
5168                 return 0;
5169
5170         if (!q->merge_bvec_fn)
5171                 return 1;
5172
5173         bvm.bi_size = bio->bi_size - prev->bv_len;
5174         if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len)
5175                 return 0;
5176         return 1;
5177 }
5178
5179 static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
5180                               struct bio *bio, u64 physical, int dev_nr,
5181                               int rw, int async)
5182 {
5183         struct btrfs_device *dev = bbio->stripes[dev_nr].dev;
5184
5185         bio->bi_private = bbio;
5186         btrfs_io_bio(bio)->stripe_index = dev_nr;
5187         bio->bi_end_io = btrfs_end_bio;
5188         bio->bi_sector = physical >> 9;
5189 #ifdef DEBUG
5190         {
5191                 struct rcu_string *name;
5192
5193                 rcu_read_lock();
5194                 name = rcu_dereference(dev->name);
5195                 pr_debug("btrfs_map_bio: rw %d, sector=%llu, dev=%lu "
5196                          "(%s id %llu), size=%u\n", rw,
5197                          (u64)bio->bi_sector, (u_long)dev->bdev->bd_dev,
5198                          name->str, dev->devid, bio->bi_size);
5199                 rcu_read_unlock();
5200         }
5201 #endif
5202         bio->bi_bdev = dev->bdev;
5203         if (async)
5204                 btrfs_schedule_bio(root, dev, rw, bio);
5205         else
5206                 btrfsic_submit_bio(rw, bio);
5207 }
5208
5209 static int breakup_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
5210                               struct bio *first_bio, struct btrfs_device *dev,
5211                               int dev_nr, int rw, int async)
5212 {
5213         struct bio_vec *bvec = first_bio->bi_io_vec;
5214         struct bio *bio;
5215         int nr_vecs = bio_get_nr_vecs(dev->bdev);
5216         u64 physical = bbio->stripes[dev_nr].physical;
5217
5218 again:
5219         bio = btrfs_bio_alloc(dev->bdev, physical >> 9, nr_vecs, GFP_NOFS);
5220         if (!bio)
5221                 return -ENOMEM;
5222
5223         while (bvec <= (first_bio->bi_io_vec + first_bio->bi_vcnt - 1)) {
5224                 if (bio_add_page(bio, bvec->bv_page, bvec->bv_len,
5225                                  bvec->bv_offset) < bvec->bv_len) {
5226                         u64 len = bio->bi_size;
5227
5228                         atomic_inc(&bbio->stripes_pending);
5229                         submit_stripe_bio(root, bbio, bio, physical, dev_nr,
5230                                           rw, async);
5231                         physical += len;
5232                         goto again;
5233                 }
5234                 bvec++;
5235         }
5236
5237         submit_stripe_bio(root, bbio, bio, physical, dev_nr, rw, async);
5238         return 0;
5239 }
5240
5241 static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical)
5242 {
5243         atomic_inc(&bbio->error);
5244         if (atomic_dec_and_test(&bbio->stripes_pending)) {
5245                 bio->bi_private = bbio->private;
5246                 bio->bi_end_io = bbio->end_io;
5247                 btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
5248                 bio->bi_sector = logical >> 9;
5249                 kfree(bbio);
5250                 bio_endio(bio, -EIO);
5251         }
5252 }
5253
5254 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
5255                   int mirror_num, int async_submit)
5256 {
5257         struct btrfs_device *dev;
5258         struct bio *first_bio = bio;
5259         u64 logical = (u64)bio->bi_sector << 9;
5260         u64 length = 0;
5261         u64 map_length;
5262         u64 *raid_map = NULL;
5263         int ret;
5264         int dev_nr = 0;
5265         int total_devs = 1;
5266         struct btrfs_bio *bbio = NULL;
5267
5268         length = bio->bi_size;
5269         map_length = length;
5270
5271         ret = __btrfs_map_block(root->fs_info, rw, logical, &map_length, &bbio,
5272                               mirror_num, &raid_map);
5273         if (ret) /* -ENOMEM */
5274                 return ret;
5275
5276         total_devs = bbio->num_stripes;
5277         bbio->orig_bio = first_bio;
5278         bbio->private = first_bio->bi_private;
5279         bbio->end_io = first_bio->bi_end_io;
5280         atomic_set(&bbio->stripes_pending, bbio->num_stripes);
5281
5282         if (raid_map) {
5283                 /* In this case, map_length has been set to the length of
5284                    a single stripe; not the whole write */
5285                 if (rw & WRITE) {
5286                         return raid56_parity_write(root, bio, bbio,
5287                                                    raid_map, map_length);
5288                 } else {
5289                         return raid56_parity_recover(root, bio, bbio,
5290                                                      raid_map, map_length,
5291                                                      mirror_num);
5292                 }
5293         }
5294
5295         if (map_length < length) {
5296                 btrfs_crit(root->fs_info, "mapping failed logical %llu bio len %llu len %llu",
5297                         (unsigned long long)logical,
5298                         (unsigned long long)length,
5299                         (unsigned long long)map_length);
5300                 BUG();
5301         }
5302
5303         while (dev_nr < total_devs) {
5304                 dev = bbio->stripes[dev_nr].dev;
5305                 if (!dev || !dev->bdev || (rw & WRITE && !dev->writeable)) {
5306                         bbio_error(bbio, first_bio, logical);
5307                         dev_nr++;
5308                         continue;
5309                 }
5310
5311                 /*
5312                  * Check and see if we're ok with this bio based on it's size
5313                  * and offset with the given device.
5314                  */
5315                 if (!bio_size_ok(dev->bdev, first_bio,
5316                                  bbio->stripes[dev_nr].physical >> 9)) {
5317                         ret = breakup_stripe_bio(root, bbio, first_bio, dev,
5318                                                  dev_nr, rw, async_submit);
5319                         BUG_ON(ret);
5320                         dev_nr++;
5321                         continue;
5322                 }
5323
5324                 if (dev_nr < total_devs - 1) {
5325                         bio = btrfs_bio_clone(first_bio, GFP_NOFS);
5326                         BUG_ON(!bio); /* -ENOMEM */
5327                 } else {
5328                         bio = first_bio;
5329                 }
5330
5331                 submit_stripe_bio(root, bbio, bio,
5332                                   bbio->stripes[dev_nr].physical, dev_nr, rw,
5333                                   async_submit);
5334                 dev_nr++;
5335         }
5336         return 0;
5337 }
5338
5339 struct btrfs_device *btrfs_find_device(struct btrfs_fs_info *fs_info, u64 devid,
5340                                        u8 *uuid, u8 *fsid)
5341 {
5342         struct btrfs_device *device;
5343         struct btrfs_fs_devices *cur_devices;
5344
5345         cur_devices = fs_info->fs_devices;
5346         while (cur_devices) {
5347                 if (!fsid ||
5348                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
5349                         device = __find_device(&cur_devices->devices,
5350                                                devid, uuid);
5351                         if (device)
5352                                 return device;
5353                 }
5354                 cur_devices = cur_devices->seed;
5355         }
5356         return NULL;
5357 }
5358
5359 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
5360                                             u64 devid, u8 *dev_uuid)
5361 {
5362         struct btrfs_device *device;
5363         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
5364
5365         device = kzalloc(sizeof(*device), GFP_NOFS);
5366         if (!device)
5367                 return NULL;
5368         list_add(&device->dev_list,
5369                  &fs_devices->devices);
5370         device->dev_root = root->fs_info->dev_root;
5371         device->devid = devid;
5372         device->work.func = pending_bios_fn;
5373         device->fs_devices = fs_devices;
5374         device->missing = 1;
5375         fs_devices->num_devices++;
5376         fs_devices->missing_devices++;
5377         spin_lock_init(&device->io_lock);
5378         INIT_LIST_HEAD(&device->dev_alloc_list);
5379         memcpy(device->uuid, dev_uuid, BTRFS_UUID_SIZE);
5380         return device;
5381 }
5382
5383 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
5384                           struct extent_buffer *leaf,
5385                           struct btrfs_chunk *chunk)
5386 {
5387         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
5388         struct map_lookup *map;
5389         struct extent_map *em;
5390         u64 logical;
5391         u64 length;
5392         u64 devid;
5393         u8 uuid[BTRFS_UUID_SIZE];
5394         int num_stripes;
5395         int ret;
5396         int i;
5397
5398         logical = key->offset;
5399         length = btrfs_chunk_length(leaf, chunk);
5400
5401         read_lock(&map_tree->map_tree.lock);
5402         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
5403         read_unlock(&map_tree->map_tree.lock);
5404
5405         /* already mapped? */
5406         if (em && em->start <= logical && em->start + em->len > logical) {
5407                 free_extent_map(em);
5408                 return 0;
5409         } else if (em) {
5410                 free_extent_map(em);
5411         }
5412
5413         em = alloc_extent_map();
5414         if (!em)
5415                 return -ENOMEM;
5416         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
5417         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
5418         if (!map) {
5419                 free_extent_map(em);
5420                 return -ENOMEM;
5421         }
5422
5423         em->bdev = (struct block_device *)map;
5424         em->start = logical;
5425         em->len = length;
5426         em->orig_start = 0;
5427         em->block_start = 0;
5428         em->block_len = em->len;
5429
5430         map->num_stripes = num_stripes;
5431         map->io_width = btrfs_chunk_io_width(leaf, chunk);
5432         map->io_align = btrfs_chunk_io_align(leaf, chunk);
5433         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
5434         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
5435         map->type = btrfs_chunk_type(leaf, chunk);
5436         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
5437         for (i = 0; i < num_stripes; i++) {
5438                 map->stripes[i].physical =
5439                         btrfs_stripe_offset_nr(leaf, chunk, i);
5440                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
5441                 read_extent_buffer(leaf, uuid, (unsigned long)
5442                                    btrfs_stripe_dev_uuid_nr(chunk, i),
5443                                    BTRFS_UUID_SIZE);
5444                 map->stripes[i].dev = btrfs_find_device(root->fs_info, devid,
5445                                                         uuid, NULL);
5446                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
5447                         kfree(map);
5448                         free_extent_map(em);
5449                         return -EIO;
5450                 }
5451                 if (!map->stripes[i].dev) {
5452                         map->stripes[i].dev =
5453                                 add_missing_dev(root, devid, uuid);
5454                         if (!map->stripes[i].dev) {
5455                                 kfree(map);
5456                                 free_extent_map(em);
5457                                 return -EIO;
5458                         }
5459                 }
5460                 map->stripes[i].dev->in_fs_metadata = 1;
5461         }
5462
5463         write_lock(&map_tree->map_tree.lock);
5464         ret = add_extent_mapping(&map_tree->map_tree, em, 0);
5465         write_unlock(&map_tree->map_tree.lock);
5466         BUG_ON(ret); /* Tree corruption */
5467         free_extent_map(em);
5468
5469         return 0;
5470 }
5471
5472 static void fill_device_from_item(struct extent_buffer *leaf,
5473                                  struct btrfs_dev_item *dev_item,
5474                                  struct btrfs_device *device)
5475 {
5476         unsigned long ptr;
5477
5478         device->devid = btrfs_device_id(leaf, dev_item);
5479         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
5480         device->total_bytes = device->disk_total_bytes;
5481         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
5482         device->type = btrfs_device_type(leaf, dev_item);
5483         device->io_align = btrfs_device_io_align(leaf, dev_item);
5484         device->io_width = btrfs_device_io_width(leaf, dev_item);
5485         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
5486         WARN_ON(device->devid == BTRFS_DEV_REPLACE_DEVID);
5487         device->is_tgtdev_for_dev_replace = 0;
5488
5489         ptr = (unsigned long)btrfs_device_uuid(dev_item);
5490         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
5491 }
5492
5493 static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
5494 {
5495         struct btrfs_fs_devices *fs_devices;
5496         int ret;
5497
5498         BUG_ON(!mutex_is_locked(&uuid_mutex));
5499
5500         fs_devices = root->fs_info->fs_devices->seed;
5501         while (fs_devices) {
5502                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
5503                         ret = 0;
5504                         goto out;
5505                 }
5506                 fs_devices = fs_devices->seed;
5507         }
5508
5509         fs_devices = find_fsid(fsid);
5510         if (!fs_devices) {
5511                 ret = -ENOENT;
5512                 goto out;
5513         }
5514
5515         fs_devices = clone_fs_devices(fs_devices);
5516         if (IS_ERR(fs_devices)) {
5517                 ret = PTR_ERR(fs_devices);
5518                 goto out;
5519         }
5520
5521         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
5522                                    root->fs_info->bdev_holder);
5523         if (ret) {
5524                 free_fs_devices(fs_devices);
5525                 goto out;
5526         }
5527
5528         if (!fs_devices->seeding) {
5529                 __btrfs_close_devices(fs_devices);
5530                 free_fs_devices(fs_devices);
5531                 ret = -EINVAL;
5532                 goto out;
5533         }
5534
5535         fs_devices->seed = root->fs_info->fs_devices->seed;
5536         root->fs_info->fs_devices->seed = fs_devices;
5537 out:
5538         return ret;
5539 }
5540
5541 static int read_one_dev(struct btrfs_root *root,
5542                         struct extent_buffer *leaf,
5543                         struct btrfs_dev_item *dev_item)
5544 {
5545         struct btrfs_device *device;
5546         u64 devid;
5547         int ret;
5548         u8 fs_uuid[BTRFS_UUID_SIZE];
5549         u8 dev_uuid[BTRFS_UUID_SIZE];
5550
5551         devid = btrfs_device_id(leaf, dev_item);
5552         read_extent_buffer(leaf, dev_uuid,
5553                            (unsigned long)btrfs_device_uuid(dev_item),
5554                            BTRFS_UUID_SIZE);
5555         read_extent_buffer(leaf, fs_uuid,
5556                            (unsigned long)btrfs_device_fsid(dev_item),
5557                            BTRFS_UUID_SIZE);
5558
5559         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
5560                 ret = open_seed_devices(root, fs_uuid);
5561                 if (ret && !btrfs_test_opt(root, DEGRADED))
5562                         return ret;
5563         }
5564
5565         device = btrfs_find_device(root->fs_info, devid, dev_uuid, fs_uuid);
5566         if (!device || !device->bdev) {
5567                 if (!btrfs_test_opt(root, DEGRADED))
5568                         return -EIO;
5569
5570                 if (!device) {
5571                         btrfs_warn(root->fs_info, "devid %llu missing",
5572                                 (unsigned long long)devid);
5573                         device = add_missing_dev(root, devid, dev_uuid);
5574                         if (!device)
5575                                 return -ENOMEM;
5576                 } else if (!device->missing) {
5577                         /*
5578                          * this happens when a device that was properly setup
5579                          * in the device info lists suddenly goes bad.
5580                          * device->bdev is NULL, and so we have to set
5581                          * device->missing to one here
5582                          */
5583                         root->fs_info->fs_devices->missing_devices++;
5584                         device->missing = 1;
5585                 }
5586         }
5587
5588         if (device->fs_devices != root->fs_info->fs_devices) {
5589                 BUG_ON(device->writeable);
5590                 if (device->generation !=
5591                     btrfs_device_generation(leaf, dev_item))
5592                         return -EINVAL;
5593         }
5594
5595         fill_device_from_item(leaf, dev_item, device);
5596         device->dev_root = root->fs_info->dev_root;
5597         device->in_fs_metadata = 1;
5598         if (device->writeable && !device->is_tgtdev_for_dev_replace) {
5599                 device->fs_devices->total_rw_bytes += device->total_bytes;
5600                 spin_lock(&root->fs_info->free_chunk_lock);
5601                 root->fs_info->free_chunk_space += device->total_bytes -
5602                         device->bytes_used;
5603                 spin_unlock(&root->fs_info->free_chunk_lock);
5604         }
5605         ret = 0;
5606         return ret;
5607 }
5608
5609 int btrfs_read_sys_array(struct btrfs_root *root)
5610 {
5611         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
5612         struct extent_buffer *sb;
5613         struct btrfs_disk_key *disk_key;
5614         struct btrfs_chunk *chunk;
5615         u8 *ptr;
5616         unsigned long sb_ptr;
5617         int ret = 0;
5618         u32 num_stripes;
5619         u32 array_size;
5620         u32 len = 0;
5621         u32 cur;
5622         struct btrfs_key key;
5623
5624         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
5625                                           BTRFS_SUPER_INFO_SIZE);
5626         if (!sb)
5627                 return -ENOMEM;
5628         btrfs_set_buffer_uptodate(sb);
5629         btrfs_set_buffer_lockdep_class(root->root_key.objectid, sb, 0);
5630         /*
5631          * The sb extent buffer is artifical and just used to read the system array.
5632          * btrfs_set_buffer_uptodate() call does not properly mark all it's
5633          * pages up-to-date when the page is larger: extent does not cover the
5634          * whole page and consequently check_page_uptodate does not find all
5635          * the page's extents up-to-date (the hole beyond sb),
5636          * write_extent_buffer then triggers a WARN_ON.
5637          *
5638          * Regular short extents go through mark_extent_buffer_dirty/writeback cycle,
5639          * but sb spans only this function. Add an explicit SetPageUptodate call
5640          * to silence the warning eg. on PowerPC 64.
5641          */
5642         if (PAGE_CACHE_SIZE > BTRFS_SUPER_INFO_SIZE)
5643                 SetPageUptodate(sb->pages[0]);
5644
5645         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
5646         array_size = btrfs_super_sys_array_size(super_copy);
5647
5648         ptr = super_copy->sys_chunk_array;
5649         sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
5650         cur = 0;
5651
5652         while (cur < array_size) {
5653                 disk_key = (struct btrfs_disk_key *)ptr;
5654                 btrfs_disk_key_to_cpu(&key, disk_key);
5655
5656                 len = sizeof(*disk_key); ptr += len;
5657                 sb_ptr += len;
5658                 cur += len;
5659
5660                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
5661                         chunk = (struct btrfs_chunk *)sb_ptr;
5662                         ret = read_one_chunk(root, &key, sb, chunk);
5663                         if (ret)
5664                                 break;
5665                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
5666                         len = btrfs_chunk_item_size(num_stripes);
5667                 } else {
5668                         ret = -EIO;
5669                         break;
5670                 }
5671                 ptr += len;
5672                 sb_ptr += len;
5673                 cur += len;
5674         }
5675         free_extent_buffer(sb);
5676         return ret;
5677 }
5678
5679 int btrfs_read_chunk_tree(struct btrfs_root *root)
5680 {
5681         struct btrfs_path *path;
5682         struct extent_buffer *leaf;
5683         struct btrfs_key key;
5684         struct btrfs_key found_key;
5685         int ret;
5686         int slot;
5687
5688         root = root->fs_info->chunk_root;
5689
5690         path = btrfs_alloc_path();
5691         if (!path)
5692                 return -ENOMEM;
5693
5694         mutex_lock(&uuid_mutex);
5695         lock_chunks(root);
5696
5697         /* first we search for all of the device items, and then we
5698          * read in all of the chunk items.  This way we can create chunk
5699          * mappings that reference all of the devices that are afound
5700          */
5701         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
5702         key.offset = 0;
5703         key.type = 0;
5704 again:
5705         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5706         if (ret < 0)
5707                 goto error;
5708         while (1) {
5709                 leaf = path->nodes[0];
5710                 slot = path->slots[0];
5711                 if (slot >= btrfs_header_nritems(leaf)) {
5712                         ret = btrfs_next_leaf(root, path);
5713                         if (ret == 0)
5714                                 continue;
5715                         if (ret < 0)
5716                                 goto error;
5717                         break;
5718                 }
5719                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5720                 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
5721                         if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
5722                                 break;
5723                         if (found_key.type == BTRFS_DEV_ITEM_KEY) {
5724                                 struct btrfs_dev_item *dev_item;
5725                                 dev_item = btrfs_item_ptr(leaf, slot,
5726                                                   struct btrfs_dev_item);
5727                                 ret = read_one_dev(root, leaf, dev_item);
5728                                 if (ret)
5729                                         goto error;
5730                         }
5731                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
5732                         struct btrfs_chunk *chunk;
5733                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
5734                         ret = read_one_chunk(root, &found_key, leaf, chunk);
5735                         if (ret)
5736                                 goto error;
5737                 }
5738                 path->slots[0]++;
5739         }
5740         if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
5741                 key.objectid = 0;
5742                 btrfs_release_path(path);
5743                 goto again;
5744         }
5745         ret = 0;
5746 error:
5747         unlock_chunks(root);
5748         mutex_unlock(&uuid_mutex);
5749
5750         btrfs_free_path(path);
5751         return ret;
5752 }
5753
5754 static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
5755 {
5756         int i;
5757
5758         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5759                 btrfs_dev_stat_reset(dev, i);
5760 }
5761
5762 int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info)
5763 {
5764         struct btrfs_key key;
5765         struct btrfs_key found_key;
5766         struct btrfs_root *dev_root = fs_info->dev_root;
5767         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
5768         struct extent_buffer *eb;
5769         int slot;
5770         int ret = 0;
5771         struct btrfs_device *device;
5772         struct btrfs_path *path = NULL;
5773         int i;
5774
5775         path = btrfs_alloc_path();
5776         if (!path) {
5777                 ret = -ENOMEM;
5778                 goto out;
5779         }
5780
5781         mutex_lock(&fs_devices->device_list_mutex);
5782         list_for_each_entry(device, &fs_devices->devices, dev_list) {
5783                 int item_size;
5784                 struct btrfs_dev_stats_item *ptr;
5785
5786                 key.objectid = 0;
5787                 key.type = BTRFS_DEV_STATS_KEY;
5788                 key.offset = device->devid;
5789                 ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
5790                 if (ret) {
5791                         __btrfs_reset_dev_stats(device);
5792                         device->dev_stats_valid = 1;
5793                         btrfs_release_path(path);
5794                         continue;
5795                 }
5796                 slot = path->slots[0];
5797                 eb = path->nodes[0];
5798                 btrfs_item_key_to_cpu(eb, &found_key, slot);
5799                 item_size = btrfs_item_size_nr(eb, slot);
5800
5801                 ptr = btrfs_item_ptr(eb, slot,
5802                                      struct btrfs_dev_stats_item);
5803
5804                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
5805                         if (item_size >= (1 + i) * sizeof(__le64))
5806                                 btrfs_dev_stat_set(device, i,
5807                                         btrfs_dev_stats_value(eb, ptr, i));
5808                         else
5809                                 btrfs_dev_stat_reset(device, i);
5810                 }
5811
5812                 device->dev_stats_valid = 1;
5813                 btrfs_dev_stat_print_on_load(device);
5814                 btrfs_release_path(path);
5815         }
5816         mutex_unlock(&fs_devices->device_list_mutex);
5817
5818 out:
5819         btrfs_free_path(path);
5820         return ret < 0 ? ret : 0;
5821 }
5822
5823 static int update_dev_stat_item(struct btrfs_trans_handle *trans,
5824                                 struct btrfs_root *dev_root,
5825                                 struct btrfs_device *device)
5826 {
5827         struct btrfs_path *path;
5828         struct btrfs_key key;
5829         struct extent_buffer *eb;
5830         struct btrfs_dev_stats_item *ptr;
5831         int ret;
5832         int i;
5833
5834         key.objectid = 0;
5835         key.type = BTRFS_DEV_STATS_KEY;
5836         key.offset = device->devid;
5837
5838         path = btrfs_alloc_path();
5839         BUG_ON(!path);
5840         ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
5841         if (ret < 0) {
5842                 printk_in_rcu(KERN_WARNING "btrfs: error %d while searching for dev_stats item for device %s!\n",
5843                               ret, rcu_str_deref(device->name));
5844                 goto out;
5845         }
5846
5847         if (ret == 0 &&
5848             btrfs_item_size_nr(path->nodes[0], path->slots[0]) < sizeof(*ptr)) {
5849                 /* need to delete old one and insert a new one */
5850                 ret = btrfs_del_item(trans, dev_root, path);
5851                 if (ret != 0) {
5852                         printk_in_rcu(KERN_WARNING "btrfs: delete too small dev_stats item for device %s failed %d!\n",
5853                                       rcu_str_deref(device->name), ret);
5854                         goto out;
5855                 }
5856                 ret = 1;
5857         }
5858
5859         if (ret == 1) {
5860                 /* need to insert a new item */
5861                 btrfs_release_path(path);
5862                 ret = btrfs_insert_empty_item(trans, dev_root, path,
5863                                               &key, sizeof(*ptr));
5864                 if (ret < 0) {
5865                         printk_in_rcu(KERN_WARNING "btrfs: insert dev_stats item for device %s failed %d!\n",
5866                                       rcu_str_deref(device->name), ret);
5867                         goto out;
5868                 }
5869         }
5870
5871         eb = path->nodes[0];
5872         ptr = btrfs_item_ptr(eb, path->slots[0], struct btrfs_dev_stats_item);
5873         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5874                 btrfs_set_dev_stats_value(eb, ptr, i,
5875                                           btrfs_dev_stat_read(device, i));
5876         btrfs_mark_buffer_dirty(eb);
5877
5878 out:
5879         btrfs_free_path(path);
5880         return ret;
5881 }
5882
5883 /*
5884  * called from commit_transaction. Writes all changed device stats to disk.
5885  */
5886 int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
5887                         struct btrfs_fs_info *fs_info)
5888 {
5889         struct btrfs_root *dev_root = fs_info->dev_root;
5890         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
5891         struct btrfs_device *device;
5892         int ret = 0;
5893
5894         mutex_lock(&fs_devices->device_list_mutex);
5895         list_for_each_entry(device, &fs_devices->devices, dev_list) {
5896                 if (!device->dev_stats_valid || !device->dev_stats_dirty)
5897                         continue;
5898
5899                 ret = update_dev_stat_item(trans, dev_root, device);
5900                 if (!ret)
5901                         device->dev_stats_dirty = 0;
5902         }
5903         mutex_unlock(&fs_devices->device_list_mutex);
5904
5905         return ret;
5906 }
5907
5908 void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index)
5909 {
5910         btrfs_dev_stat_inc(dev, index);
5911         btrfs_dev_stat_print_on_error(dev);
5912 }
5913
5914 static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
5915 {
5916         if (!dev->dev_stats_valid)
5917                 return;
5918         printk_ratelimited_in_rcu(KERN_ERR
5919                            "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
5920                            rcu_str_deref(dev->name),
5921                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
5922                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
5923                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
5924                            btrfs_dev_stat_read(dev,
5925                                                BTRFS_DEV_STAT_CORRUPTION_ERRS),
5926                            btrfs_dev_stat_read(dev,
5927                                                BTRFS_DEV_STAT_GENERATION_ERRS));
5928 }
5929
5930 static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
5931 {
5932         int i;
5933
5934         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5935                 if (btrfs_dev_stat_read(dev, i) != 0)
5936                         break;
5937         if (i == BTRFS_DEV_STAT_VALUES_MAX)
5938                 return; /* all values == 0, suppress message */
5939
5940         printk_in_rcu(KERN_INFO "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
5941                rcu_str_deref(dev->name),
5942                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
5943                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
5944                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
5945                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
5946                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
5947 }
5948
5949 int btrfs_get_dev_stats(struct btrfs_root *root,
5950                         struct btrfs_ioctl_get_dev_stats *stats)
5951 {
5952         struct btrfs_device *dev;
5953         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
5954         int i;
5955
5956         mutex_lock(&fs_devices->device_list_mutex);
5957         dev = btrfs_find_device(root->fs_info, stats->devid, NULL, NULL);
5958         mutex_unlock(&fs_devices->device_list_mutex);
5959
5960         if (!dev) {
5961                 printk(KERN_WARNING
5962                        "btrfs: get dev_stats failed, device not found\n");
5963                 return -ENODEV;
5964         } else if (!dev->dev_stats_valid) {
5965                 printk(KERN_WARNING
5966                        "btrfs: get dev_stats failed, not yet valid\n");
5967                 return -ENODEV;
5968         } else if (stats->flags & BTRFS_DEV_STATS_RESET) {
5969                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
5970                         if (stats->nr_items > i)
5971                                 stats->values[i] =
5972                                         btrfs_dev_stat_read_and_reset(dev, i);
5973                         else
5974                                 btrfs_dev_stat_reset(dev, i);
5975                 }
5976         } else {
5977                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
5978                         if (stats->nr_items > i)
5979                                 stats->values[i] = btrfs_dev_stat_read(dev, i);
5980         }
5981         if (stats->nr_items > BTRFS_DEV_STAT_VALUES_MAX)
5982                 stats->nr_items = BTRFS_DEV_STAT_VALUES_MAX;
5983         return 0;
5984 }
5985
5986 int btrfs_scratch_superblock(struct btrfs_device *device)
5987 {
5988         struct buffer_head *bh;
5989         struct btrfs_super_block *disk_super;
5990
5991         bh = btrfs_read_dev_super(device->bdev);
5992         if (!bh)
5993                 return -EINVAL;
5994         disk_super = (struct btrfs_super_block *)bh->b_data;
5995
5996         memset(&disk_super->magic, 0, sizeof(disk_super->magic));
5997         set_buffer_dirty(bh);
5998         sync_dirty_buffer(bh);
5999         brelse(bh);
6000
6001         return 0;
6002 }