drivers/block/rbd.c

   1
   2 /*
   3    rbd.c -- Export ceph rados objects as a Linux block device
   4
   5
   6    based on drivers/block/osdblk.c:
   7
   8    Copyright 2009 Red Hat, Inc.
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program; see the file COPYING.  If not, write to
  21    the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  22
  23
  24
  25    For usage instructions, please refer to:
  26
  27                  Documentation/ABI/testing/sysfs-bus-rbd
  28
  29  */
  30
  31 #include <linux/ceph/libceph.h>
  32 #include <linux/ceph/osd_client.h>
  33 #include <linux/ceph/mon_client.h>
  34 #include <linux/ceph/cls_lock_client.h>
  35 #include <linux/ceph/decode.h>
  36 #include <linux/parser.h>
  37 #include <linux/bsearch.h>
  38
  39 #include <linux/kernel.h>
  40 #include <linux/device.h>
  41 #include <linux/module.h>
  42 #include <linux/blk-mq.h>
  43 #include <linux/fs.h>
  44 #include <linux/blkdev.h>
  45 #include <linux/slab.h>
  46 #include <linux/idr.h>
  47 #include <linux/workqueue.h>
  48
  49 #include "rbd_types.h"
  50
  51 #define RBD_DEBUG       /* Activate rbd_assert() calls */
  52
  53 /*
  54  * The basic unit of block I/O is a sector.  It is interpreted in a
  55  * number of contexts in Linux (blk, bio, genhd), but the default is
  56  * universally 512 bytes.  These symbols are just slightly more
  57  * meaningful than the bare numbers they represent.
  58  */
  59 #define SECTOR_SHIFT    9
  60 #define SECTOR_SIZE     (1ULL << SECTOR_SHIFT)
  61
  62 /*
  63  * Increment the given counter and return its updated value.
  64  * If the counter is already 0 it will not be incremented.
  65  * If the counter is already at its maximum value returns
  66  * -EINVAL without updating it.
  67  */
  68 static int atomic_inc_return_safe(atomic_t *v)
  69 {
  70         unsigned int counter;
  71
  72         counter = (unsigned int)__atomic_add_unless(v, 1, 0);
  73         if (counter <= (unsigned int)INT_MAX)
  74                 return (int)counter;
  75
  76         atomic_dec(v);
  77
  78         return -EINVAL;
  79 }
  80
  81 /* Decrement the counter.  Return the resulting value, or -EINVAL */
  82 static int atomic_dec_return_safe(atomic_t *v)
  83 {
  84         int counter;
  85
  86         counter = atomic_dec_return(v);
  87         if (counter >= 0)
  88                 return counter;
  89
  90         atomic_inc(v);
  91
  92         return -EINVAL;
  93 }
  94
  95 #define RBD_DRV_NAME "rbd"
  96
  97 #define RBD_MINORS_PER_MAJOR            256
  98 #define RBD_SINGLE_MAJOR_PART_SHIFT     4
  99
 100 #define RBD_MAX_PARENT_CHAIN_LEN        16
 101
 102 #define RBD_SNAP_DEV_NAME_PREFIX        "snap_"
 103 #define RBD_MAX_SNAP_NAME_LEN   \
 104                         (NAME_MAX - (sizeof (RBD_SNAP_DEV_NAME_PREFIX) - 1))
 105
 106 #define RBD_MAX_SNAP_COUNT      510     /* allows max snapc to fit in 4KB */
 107
 108 #define RBD_SNAP_HEAD_NAME      "-"
 109
 110 #define BAD_SNAP_INDEX  U32_MAX         /* invalid index into snap array */
 111
 112 /* This allows a single page to hold an image name sent by OSD */
 113 #define RBD_IMAGE_NAME_LEN_MAX  (PAGE_SIZE - sizeof (__le32) - 1)
 114 #define RBD_IMAGE_ID_LEN_MAX    64
 115
 116 #define RBD_OBJ_PREFIX_LEN_MAX  64
 117
 118 #define RBD_NOTIFY_TIMEOUT      5       /* seconds */
 119 #define RBD_RETRY_DELAY         msecs_to_jiffies(1000)
 120
 121 /* Feature bits */
 122
 123 #define RBD_FEATURE_LAYERING    (1<<0)
 124 #define RBD_FEATURE_STRIPINGV2  (1<<1)
 125 #define RBD_FEATURE_EXCLUSIVE_LOCK (1<<2)
 126 #define RBD_FEATURE_DATA_POOL (1<<7)
 127 #define RBD_FEATURES_ALL        (RBD_FEATURE_LAYERING |         \
 128                                  RBD_FEATURE_STRIPINGV2 |       \
 129                                  RBD_FEATURE_EXCLUSIVE_LOCK |   \
 130                                  RBD_FEATURE_DATA_POOL)
 131
 132 /* Features supported by this (client software) implementation. */
 133
 134 #define RBD_FEATURES_SUPPORTED  (RBD_FEATURES_ALL)
 135
 136 /*
 137  * An RBD device name will be "rbd#", where the "rbd" comes from
 138  * RBD_DRV_NAME above, and # is a unique integer identifier.
 139  */
 140 #define DEV_NAME_LEN            32
 141
 142 /*
 143  * block device image metadata (in-memory version)
 144  */
 145 struct rbd_image_header {
 146         /* These six fields never change for a given rbd image */
 147         char *object_prefix;
 148         __u8 obj_order;
 149         u64 stripe_unit;
 150         u64 stripe_count;
 151         s64 data_pool_id;
 152         u64 features;           /* Might be changeable someday? */
 153
 154         /* The remaining fields need to be updated occasionally */
 155         u64 image_size;
 156         struct ceph_snap_context *snapc;
 157         char *snap_names;       /* format 1 only */
 158         u64 *snap_sizes;        /* format 1 only */
 159 };
 160
 161 /*
 162  * An rbd image specification.
 163  *
 164  * The tuple (pool_id, image_id, snap_id) is sufficient to uniquely
 165  * identify an image.  Each rbd_dev structure includes a pointer to
 166  * an rbd_spec structure that encapsulates this identity.
 167  *
 168  * Each of the id's in an rbd_spec has an associated name.  For a
 169  * user-mapped image, the names are supplied and the id's associated
 170  * with them are looked up.  For a layered image, a parent image is
 171  * defined by the tuple, and the names are looked up.
 172  *
 173  * An rbd_dev structure contains a parent_spec pointer which is
 174  * non-null if the image it represents is a child in a layered
 175  * image.  This pointer will refer to the rbd_spec structure used
 176  * by the parent rbd_dev for its own identity (i.e., the structure
 177  * is shared between the parent and child).
 178  *
 179  * Since these structures are populated once, during the discovery
 180  * phase of image construction, they are effectively immutable so
 181  * we make no effort to synchronize access to them.
 182  *
 183  * Note that code herein does not assume the image name is known (it
 184  * could be a null pointer).
 185  */
 186 struct rbd_spec {
 187         u64             pool_id;
 188         const char      *pool_name;
 189
 190         const char      *image_id;
 191         const char      *image_name;
 192
 193         u64             snap_id;
 194         const char      *snap_name;
 195
 196         struct kref     kref;
 197 };
 198
 199 /*
 200  * an instance of the client.  multiple devices may share an rbd client.
 201  */
 202 struct rbd_client {
 203         struct ceph_client      *client;
 204         struct kref             kref;
 205         struct list_head        node;
 206 };
 207
 208 struct rbd_img_request;
 209 typedef void (*rbd_img_callback_t)(struct rbd_img_request *);
 210
 211 #define BAD_WHICH       U32_MAX         /* Good which or bad which, which? */
 212
 213 struct rbd_obj_request;
 214 typedef void (*rbd_obj_callback_t)(struct rbd_obj_request *);
 215
 216 enum obj_request_type {
 217         OBJ_REQUEST_NODATA, OBJ_REQUEST_BIO, OBJ_REQUEST_PAGES
 218 };
 219
 220 enum obj_operation_type {
 221         OBJ_OP_WRITE,
 222         OBJ_OP_READ,
 223         OBJ_OP_DISCARD,
 224 };
 225
 226 enum obj_req_flags {
 227         OBJ_REQ_DONE,           /* completion flag: not done = 0, done = 1 */
 228         OBJ_REQ_IMG_DATA,       /* object usage: standalone = 0, image = 1 */
 229         OBJ_REQ_KNOWN,          /* EXISTS flag valid: no = 0, yes = 1 */
 230         OBJ_REQ_EXISTS,         /* target exists: no = 0, yes = 1 */
 231 };
 232
 233 struct rbd_obj_request {
 234         u64                     object_no;
 235         u64                     offset;         /* object start byte */
 236         u64                     length;         /* bytes from offset */
 237         unsigned long           flags;
 238
 239         /*
 240          * An object request associated with an image will have its
 241          * img_data flag set; a standalone object request will not.
 242          *
 243          * A standalone object request will have which == BAD_WHICH
 244          * and a null obj_request pointer.
 245          *
 246          * An object request initiated in support of a layered image
 247          * object (to check for its existence before a write) will
 248          * have which == BAD_WHICH and a non-null obj_request pointer.
 249          *
 250          * Finally, an object request for rbd image data will have
 251          * which != BAD_WHICH, and will have a non-null img_request
 252          * pointer.  The value of which will be in the range
 253          * 0..(img_request->obj_request_count-1).
 254          */
 255         union {
 256                 struct rbd_obj_request  *obj_request;   /* STAT op */
 257                 struct {
 258                         struct rbd_img_request  *img_request;
 259                         u64                     img_offset;
 260                         /* links for img_request->obj_requests list */
 261                         struct list_head        links;
 262                 };
 263         };
 264         u32                     which;          /* posn image request list */
 265
 266         enum obj_request_type   type;
 267         union {
 268                 struct bio      *bio_list;
 269                 struct {
 270                         struct page     **pages;
 271                         u32             page_count;
 272                 };
 273         };
 274         struct page             **copyup_pages;
 275         u32                     copyup_page_count;
 276
 277         struct ceph_osd_request *osd_req;
 278
 279         u64                     xferred;        /* bytes transferred */
 280         int                     result;
 281
 282         rbd_obj_callback_t      callback;
 283         struct completion       completion;
 284
 285         struct kref             kref;
 286 };
 287
 288 enum img_req_flags {
 289         IMG_REQ_WRITE,          /* I/O direction: read = 0, write = 1 */
 290         IMG_REQ_CHILD,          /* initiator: block = 0, child image = 1 */
 291         IMG_REQ_LAYERED,        /* ENOENT handling: normal = 0, layered = 1 */
 292         IMG_REQ_DISCARD,        /* discard: normal = 0, discard request = 1 */
 293 };
 294
 295 struct rbd_img_request {
 296         struct rbd_device       *rbd_dev;
 297         u64                     offset; /* starting image byte offset */
 298         u64                     length; /* byte count from offset */
 299         unsigned long           flags;
 300         union {
 301                 u64                     snap_id;        /* for reads */
 302                 struct ceph_snap_context *snapc;        /* for writes */
 303         };
 304         union {
 305                 struct request          *rq;            /* block request */
 306                 struct rbd_obj_request  *obj_request;   /* obj req initiator */
 307         };
 308         struct page             **copyup_pages;
 309         u32                     copyup_page_count;
 310         spinlock_t              completion_lock;/* protects next_completion */
 311         u32                     next_completion;
 312         rbd_img_callback_t      callback;
 313         u64                     xferred;/* aggregate bytes transferred */
 314         int                     result; /* first nonzero obj_request result */
 315
 316         u32                     obj_request_count;
 317         struct list_head        obj_requests;   /* rbd_obj_request structs */
 318
 319         struct kref             kref;
 320 };
 321
 322 #define for_each_obj_request(ireq, oreq) \
 323         list_for_each_entry(oreq, &(ireq)->obj_requests, links)
 324 #define for_each_obj_request_from(ireq, oreq) \
 325         list_for_each_entry_from(oreq, &(ireq)->obj_requests, links)
 326 #define for_each_obj_request_safe(ireq, oreq, n) \
 327         list_for_each_entry_safe_reverse(oreq, n, &(ireq)->obj_requests, links)
 328
 329 enum rbd_watch_state {
 330         RBD_WATCH_STATE_UNREGISTERED,
 331         RBD_WATCH_STATE_REGISTERED,
 332         RBD_WATCH_STATE_ERROR,
 333 };
 334
 335 enum rbd_lock_state {
 336         RBD_LOCK_STATE_UNLOCKED,
 337         RBD_LOCK_STATE_LOCKED,
 338         RBD_LOCK_STATE_RELEASING,
 339 };
 340
 341 /* WatchNotify::ClientId */
 342 struct rbd_client_id {
 343         u64 gid;
 344         u64 handle;
 345 };
 346
 347 struct rbd_mapping {
 348         u64                     size;
 349         u64                     features;
 350         bool                    read_only;
 351 };
 352
 353 /*
 354  * a single device
 355  */
 356 struct rbd_device {
 357         int                     dev_id;         /* blkdev unique id */
 358
 359         int                     major;          /* blkdev assigned major */
 360         int                     minor;
 361         struct gendisk          *disk;          /* blkdev's gendisk and rq */
 362
 363         u32                     image_format;   /* Either 1 or 2 */
 364         struct rbd_client       *rbd_client;
 365
 366         char                    name[DEV_NAME_LEN]; /* blkdev name, e.g. rbd3 */
 367
 368         spinlock_t              lock;           /* queue, flags, open_count */
 369
 370         struct rbd_image_header header;
 371         unsigned long           flags;          /* possibly lock protected */
 372         struct rbd_spec         *spec;
 373         struct rbd_options      *opts;
 374         char                    *config_info;   /* add{,_single_major} string */
 375
 376         struct ceph_object_id   header_oid;
 377         struct ceph_object_locator header_oloc;
 378
 379         struct ceph_file_layout layout;         /* used for all rbd requests */
 380
 381         struct mutex            watch_mutex;
 382         enum rbd_watch_state    watch_state;
 383         struct ceph_osd_linger_request *watch_handle;
 384         u64                     watch_cookie;
 385         struct delayed_work     watch_dwork;
 386
 387         struct rw_semaphore     lock_rwsem;
 388         enum rbd_lock_state     lock_state;
 389         struct rbd_client_id    owner_cid;
 390         struct work_struct      acquired_lock_work;
 391         struct work_struct      released_lock_work;
 392         struct delayed_work     lock_dwork;
 393         struct work_struct      unlock_work;
 394         wait_queue_head_t       lock_waitq;
 395
 396         struct workqueue_struct *task_wq;
 397
 398         struct rbd_spec         *parent_spec;
 399         u64                     parent_overlap;
 400         atomic_t                parent_ref;
 401         struct rbd_device       *parent;
 402
 403         /* Block layer tags. */
 404         struct blk_mq_tag_set   tag_set;
 405
 406         /* protects updating the header */
 407         struct rw_semaphore     header_rwsem;
 408
 409         struct rbd_mapping      mapping;
 410
 411         struct list_head        node;
 412
 413         /* sysfs related */
 414         struct device           dev;
 415         unsigned long           open_count;     /* protected by lock */
 416 };
 417
 418 /*
 419  * Flag bits for rbd_dev->flags:
 420  * - REMOVING (which is coupled with rbd_dev->open_count) is protected
 421  *   by rbd_dev->lock
 422  * - BLACKLISTED is protected by rbd_dev->lock_rwsem
 423  */
 424 enum rbd_dev_flags {
 425         RBD_DEV_FLAG_EXISTS,    /* mapped snapshot has not been deleted */
 426         RBD_DEV_FLAG_REMOVING,  /* this mapping is being removed */
 427         RBD_DEV_FLAG_BLACKLISTED, /* our ceph_client is blacklisted */
 428 };
 429
 430 static DEFINE_MUTEX(client_mutex);      /* Serialize client creation */
 431
 432 static LIST_HEAD(rbd_dev_list);    /* devices */
 433 static DEFINE_SPINLOCK(rbd_dev_list_lock);
 434
 435 static LIST_HEAD(rbd_client_list);              /* clients */
 436 static DEFINE_SPINLOCK(rbd_client_list_lock);
 437
 438 /* Slab caches for frequently-allocated structures */
 439
 440 static struct kmem_cache        *rbd_img_request_cache;
 441 static struct kmem_cache        *rbd_obj_request_cache;
 442
 443 static int rbd_major;
 444 static DEFINE_IDA(rbd_dev_id_ida);
 445
 446 static struct workqueue_struct *rbd_wq;
 447
 448 /*
 449  * Default to false for now, as single-major requires >= 0.75 version of
 450  * userspace rbd utility.
 451  */
 452 static bool single_major = false;
 453 module_param(single_major, bool, S_IRUGO);
 454 MODULE_PARM_DESC(single_major, "Use a single major number for all rbd devices (default: false)");
 455
 456 static int rbd_img_request_submit(struct rbd_img_request *img_request);
 457
 458 static ssize_t rbd_add(struct bus_type *bus, const char *buf,
 459                        size_t count);
 460 static ssize_t rbd_remove(struct bus_type *bus, const char *buf,
 461                           size_t count);
 462 static ssize_t rbd_add_single_major(struct bus_type *bus, const char *buf,
 463                                     size_t count);
 464 static ssize_t rbd_remove_single_major(struct bus_type *bus, const char *buf,
 465                                        size_t count);
 466 static int rbd_dev_image_probe(struct rbd_device *rbd_dev, int depth);
 467 static void rbd_spec_put(struct rbd_spec *spec);
 468
 469 static int rbd_dev_id_to_minor(int dev_id)
 470 {
 471         return dev_id << RBD_SINGLE_MAJOR_PART_SHIFT;
 472 }
 473
 474 static int minor_to_rbd_dev_id(int minor)
 475 {
 476         return minor >> RBD_SINGLE_MAJOR_PART_SHIFT;
 477 }
 478
 479 static bool rbd_is_lock_supported(struct rbd_device *rbd_dev)
 480 {
 481         return (rbd_dev->header.features & RBD_FEATURE_EXCLUSIVE_LOCK) &&
 482                rbd_dev->spec->snap_id == CEPH_NOSNAP &&
 483                !rbd_dev->mapping.read_only;
 484 }
 485
 486 static bool __rbd_is_lock_owner(struct rbd_device *rbd_dev)
 487 {
 488         return rbd_dev->lock_state == RBD_LOCK_STATE_LOCKED ||
 489                rbd_dev->lock_state == RBD_LOCK_STATE_RELEASING;
 490 }
 491
 492 static bool rbd_is_lock_owner(struct rbd_device *rbd_dev)
 493 {
 494         bool is_lock_owner;
 495
 496         down_read(&rbd_dev->lock_rwsem);
 497         is_lock_owner = __rbd_is_lock_owner(rbd_dev);
 498         up_read(&rbd_dev->lock_rwsem);
 499         return is_lock_owner;
 500 }
 501
 502 static BUS_ATTR(add, S_IWUSR, NULL, rbd_add);
 503 static BUS_ATTR(remove, S_IWUSR, NULL, rbd_remove);
 504 static BUS_ATTR(add_single_major, S_IWUSR, NULL, rbd_add_single_major);
 505 static BUS_ATTR(remove_single_major, S_IWUSR, NULL, rbd_remove_single_major);
 506
 507 static struct attribute *rbd_bus_attrs[] = {
 508         &bus_attr_add.attr,
 509         &bus_attr_remove.attr,
 510         &bus_attr_add_single_major.attr,
 511         &bus_attr_remove_single_major.attr,
 512         NULL,
 513 };
 514
 515 static umode_t rbd_bus_is_visible(struct kobject *kobj,
 516                                   struct attribute *attr, int index)
 517 {
 518         if (!single_major &&
 519             (attr == &bus_attr_add_single_major.attr ||
 520              attr == &bus_attr_remove_single_major.attr))
 521                 return 0;
 522
 523         return attr->mode;
 524 }
 525
 526 static const struct attribute_group rbd_bus_group = {
 527         .attrs = rbd_bus_attrs,
 528         .is_visible = rbd_bus_is_visible,
 529 };
 530 __ATTRIBUTE_GROUPS(rbd_bus);
 531
 532 static struct bus_type rbd_bus_type = {
 533         .name           = "rbd",
 534         .bus_groups     = rbd_bus_groups,
 535 };
 536
 537 static void rbd_root_dev_release(struct device *dev)
 538 {
 539 }
 540
 541 static struct device rbd_root_dev = {
 542         .init_name =    "rbd",
 543         .release =      rbd_root_dev_release,
 544 };
 545
 546 static __printf(2, 3)
 547 void rbd_warn(struct rbd_device *rbd_dev, const char *fmt, ...)
 548 {
 549         struct va_format vaf;
 550         va_list args;
 551
 552         va_start(args, fmt);
 553         vaf.fmt = fmt;
 554         vaf.va = &args;
 555
 556         if (!rbd_dev)
 557                 printk(KERN_WARNING "%s: %pV\n", RBD_DRV_NAME, &vaf);
 558         else if (rbd_dev->disk)
 559                 printk(KERN_WARNING "%s: %s: %pV\n",
 560                         RBD_DRV_NAME, rbd_dev->disk->disk_name, &vaf);
 561         else if (rbd_dev->spec && rbd_dev->spec->image_name)
 562                 printk(KERN_WARNING "%s: image %s: %pV\n",
 563                         RBD_DRV_NAME, rbd_dev->spec->image_name, &vaf);
 564         else if (rbd_dev->spec && rbd_dev->spec->image_id)
 565                 printk(KERN_WARNING "%s: id %s: %pV\n",
 566                         RBD_DRV_NAME, rbd_dev->spec->image_id, &vaf);
 567         else    /* punt */
 568                 printk(KERN_WARNING "%s: rbd_dev %p: %pV\n",
 569                         RBD_DRV_NAME, rbd_dev, &vaf);
 570         va_end(args);
 571 }
 572
 573 #ifdef RBD_DEBUG
 574 #define rbd_assert(expr)                                                \
 575                 if (unlikely(!(expr))) {                                \
 576                         printk(KERN_ERR "\nAssertion failure in %s() "  \
 577                                                 "at line %d:\n\n"       \
 578                                         "\trbd_assert(%s);\n\n",        \
 579                                         __func__, __LINE__, #expr);     \
 580                         BUG();                                          \
 581                 }
 582 #else /* !RBD_DEBUG */
 583 #  define rbd_assert(expr)      ((void) 0)
 584 #endif /* !RBD_DEBUG */
 585
 586 static void rbd_osd_copyup_callback(struct rbd_obj_request *obj_request);
 587 static int rbd_img_obj_request_submit(struct rbd_obj_request *obj_request);
 588 static void rbd_img_parent_read(struct rbd_obj_request *obj_request);
 589 static void rbd_dev_remove_parent(struct rbd_device *rbd_dev);
 590
 591 static int rbd_dev_refresh(struct rbd_device *rbd_dev);
 592 static int rbd_dev_v2_header_onetime(struct rbd_device *rbd_dev);
 593 static int rbd_dev_header_info(struct rbd_device *rbd_dev);
 594 static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev);
 595 static const char *rbd_dev_v2_snap_name(struct rbd_device *rbd_dev,
 596                                         u64 snap_id);
 597 static int _rbd_dev_v2_snap_size(struct rbd_device *rbd_dev, u64 snap_id,
 598                                 u8 *order, u64 *snap_size);
 599 static int _rbd_dev_v2_snap_features(struct rbd_device *rbd_dev, u64 snap_id,
 600                 u64 *snap_features);
 601
 602 static int rbd_open(struct block_device *bdev, fmode_t mode)
 603 {
 604         struct rbd_device *rbd_dev = bdev->bd_disk->private_data;
 605         bool removing = false;
 606
 607         if ((mode & FMODE_WRITE) && rbd_dev->mapping.read_only)
 608                 return -EROFS;
 609
 610         spin_lock_irq(&rbd_dev->lock);
 611         if (test_bit(RBD_DEV_FLAG_REMOVING, &rbd_dev->flags))
 612                 removing = true;
 613         else
 614                 rbd_dev->open_count++;
 615         spin_unlock_irq(&rbd_dev->lock);
 616         if (removing)
 617                 return -ENOENT;
 618
 619         (void) get_device(&rbd_dev->dev);
 620
 621         return 0;
 622 }
 623
 624 static void rbd_release(struct gendisk *disk, fmode_t mode)
 625 {
 626         struct rbd_device *rbd_dev = disk->private_data;
 627         unsigned long open_count_before;
 628
 629         spin_lock_irq(&rbd_dev->lock);
 630         open_count_before = rbd_dev->open_count--;
 631         spin_unlock_irq(&rbd_dev->lock);
 632         rbd_assert(open_count_before > 0);
 633
 634         put_device(&rbd_dev->dev);
 635 }
 636
 637 static int rbd_ioctl_set_ro(struct rbd_device *rbd_dev, unsigned long arg)
 638 {
 639         int ret = 0;
 640         int val;
 641         bool ro;
 642         bool ro_changed = false;
 643
 644         /* get_user() may sleep, so call it before taking rbd_dev->lock */
 645         if (get_user(val, (int __user *)(arg)))
 646                 return -EFAULT;
 647
 648         ro = val ? true : false;
 649         /* Snapshot doesn't allow to write*/
 650         if (rbd_dev->spec->snap_id != CEPH_NOSNAP && !ro)
 651                 return -EROFS;
 652
 653         spin_lock_irq(&rbd_dev->lock);
 654         /* prevent others open this device */
 655         if (rbd_dev->open_count > 1) {
 656                 ret = -EBUSY;
 657                 goto out;
 658         }
 659
 660         if (rbd_dev->mapping.read_only != ro) {
 661                 rbd_dev->mapping.read_only = ro;
 662                 ro_changed = true;
 663         }
 664
 665 out:
 666         spin_unlock_irq(&rbd_dev->lock);
 667         /* set_disk_ro() may sleep, so call it after releasing rbd_dev->lock */
 668         if (ret == 0 && ro_changed)
 669                 set_disk_ro(rbd_dev->disk, ro ? 1 : 0);
 670
 671         return ret;
 672 }
 673
 674 static int rbd_ioctl(struct block_device *bdev, fmode_t mode,
 675                         unsigned int cmd, unsigned long arg)
 676 {
 677         struct rbd_device *rbd_dev = bdev->bd_disk->private_data;
 678         int ret = 0;
 679
 680         switch (cmd) {
 681         case BLKROSET:
 682                 ret = rbd_ioctl_set_ro(rbd_dev, arg);
 683                 break;
 684         default:
 685                 ret = -ENOTTY;
 686         }
 687
 688         return ret;
 689 }
 690
 691 #ifdef CONFIG_COMPAT
 692 static int rbd_compat_ioctl(struct block_device *bdev, fmode_t mode,
 693                                 unsigned int cmd, unsigned long arg)
 694 {
 695         return rbd_ioctl(bdev, mode, cmd, arg);
 696 }
 697 #endif /* CONFIG_COMPAT */
 698
 699 static const struct block_device_operations rbd_bd_ops = {
 700         .owner                  = THIS_MODULE,
 701         .open                   = rbd_open,
 702         .release                = rbd_release,
 703         .ioctl                  = rbd_ioctl,
 704 #ifdef CONFIG_COMPAT
 705         .compat_ioctl           = rbd_compat_ioctl,
 706 #endif
 707 };
 708
 709 /*
 710  * Initialize an rbd client instance.  Success or not, this function
 711  * consumes ceph_opts.  Caller holds client_mutex.
 712  */
 713 static struct rbd_client *rbd_client_create(struct ceph_options *ceph_opts)
 714 {
 715         struct rbd_client *rbdc;
 716         int ret = -ENOMEM;
 717
 718         dout("%s:\n", __func__);
 719         rbdc = kmalloc(sizeof(struct rbd_client), GFP_KERNEL);
 720         if (!rbdc)
 721                 goto out_opt;
 722
 723         kref_init(&rbdc->kref);
 724         INIT_LIST_HEAD(&rbdc->node);
 725
 726         rbdc->client = ceph_create_client(ceph_opts, rbdc, 0, 0);
 727         if (IS_ERR(rbdc->client))
 728                 goto out_rbdc;
 729         ceph_opts = NULL; /* Now rbdc->client is responsible for ceph_opts */
 730
 731         ret = ceph_open_session(rbdc->client);
 732         if (ret < 0)
 733                 goto out_client;
 734
 735         spin_lock(&rbd_client_list_lock);
 736         list_add_tail(&rbdc->node, &rbd_client_list);
 737         spin_unlock(&rbd_client_list_lock);
 738
 739         dout("%s: rbdc %p\n", __func__, rbdc);
 740
 741         return rbdc;
 742 out_client:
 743         ceph_destroy_client(rbdc->client);
 744 out_rbdc:
 745         kfree(rbdc);
 746 out_opt:
 747         if (ceph_opts)
 748                 ceph_destroy_options(ceph_opts);
 749         dout("%s: error %d\n", __func__, ret);
 750
 751         return ERR_PTR(ret);
 752 }
 753
 754 static struct rbd_client *__rbd_get_client(struct rbd_client *rbdc)
 755 {
 756         kref_get(&rbdc->kref);
 757
 758         return rbdc;
 759 }
 760
 761 /*
 762  * Find a ceph client with specific addr and configuration.  If
 763  * found, bump its reference count.
 764  */
 765 static struct rbd_client *rbd_client_find(struct ceph_options *ceph_opts)
 766 {
 767         struct rbd_client *client_node;
 768         bool found = false;
 769
 770         if (ceph_opts->flags & CEPH_OPT_NOSHARE)
 771                 return NULL;
 772
 773         spin_lock(&rbd_client_list_lock);
 774         list_for_each_entry(client_node, &rbd_client_list, node) {
 775                 if (!ceph_compare_options(ceph_opts, client_node->client)) {
 776                         __rbd_get_client(client_node);
 777
 778                         found = true;
 779                         break;
 780                 }
 781         }
 782         spin_unlock(&rbd_client_list_lock);
 783
 784         return found ? client_node : NULL;
 785 }
 786
 787 /*
 788  * (Per device) rbd map options
 789  */
 790 enum {
 791         Opt_queue_depth,
 792         Opt_last_int,
 793         /* int args above */
 794         Opt_last_string,
 795         /* string args above */
 796         Opt_read_only,
 797         Opt_read_write,
 798         Opt_lock_on_read,
 799         Opt_err
 800 };
 801
 802 static match_table_t rbd_opts_tokens = {
 803         {Opt_queue_depth, "queue_depth=%d"},
 804         /* int args above */
 805         /* string args above */
 806         {Opt_read_only, "read_only"},
 807         {Opt_read_only, "ro"},          /* Alternate spelling */
 808         {Opt_read_write, "read_write"},
 809         {Opt_read_write, "rw"},         /* Alternate spelling */
 810         {Opt_lock_on_read, "lock_on_read"},
 811         {Opt_err, NULL}
 812 };
 813
 814 struct rbd_options {
 815         int     queue_depth;
 816         bool    read_only;
 817         bool    lock_on_read;
 818 };
 819
 820 #define RBD_QUEUE_DEPTH_DEFAULT BLKDEV_MAX_RQ
 821 #define RBD_READ_ONLY_DEFAULT   false
 822 #define RBD_LOCK_ON_READ_DEFAULT false
 823
 824 static int parse_rbd_opts_token(char *c, void *private)
 825 {
 826         struct rbd_options *rbd_opts = private;
 827         substring_t argstr[MAX_OPT_ARGS];
 828         int token, intval, ret;
 829
 830         token = match_token(c, rbd_opts_tokens, argstr);
 831         if (token < Opt_last_int) {
 832                 ret = match_int(&argstr[0], &intval);
 833                 if (ret < 0) {
 834                         pr_err("bad mount option arg (not int) at '%s'\n", c);
 835                         return ret;
 836                 }
 837                 dout("got int token %d val %d\n", token, intval);
 838         } else if (token > Opt_last_int && token < Opt_last_string) {
 839                 dout("got string token %d val %s\n", token, argstr[0].from);
 840         } else {
 841                 dout("got token %d\n", token);
 842         }
 843
 844         switch (token) {
 845         case Opt_queue_depth:
 846                 if (intval < 1) {
 847                         pr_err("queue_depth out of range\n");
 848                         return -EINVAL;
 849                 }
 850                 rbd_opts->queue_depth = intval;
 851                 break;
 852         case Opt_read_only:
 853                 rbd_opts->read_only = true;
 854                 break;
 855         case Opt_read_write:
 856                 rbd_opts->read_only = false;
 857                 break;
 858         case Opt_lock_on_read:
 859                 rbd_opts->lock_on_read = true;
 860                 break;
 861         default:
 862                 /* libceph prints "bad option" msg */
 863                 return -EINVAL;
 864         }
 865
 866         return 0;
 867 }
 868
 869 static char* obj_op_name(enum obj_operation_type op_type)
 870 {
 871         switch (op_type) {
 872         case OBJ_OP_READ:
 873                 return "read";
 874         case OBJ_OP_WRITE:
 875                 return "write";
 876         case OBJ_OP_DISCARD:
 877                 return "discard";
 878         default:
 879                 return "???";
 880         }
 881 }
 882
 883 /*
 884  * Get a ceph client with specific addr and configuration, if one does
 885  * not exist create it.  Either way, ceph_opts is consumed by this
 886  * function.
 887  */
 888 static struct rbd_client *rbd_get_client(struct ceph_options *ceph_opts)
 889 {
 890         struct rbd_client *rbdc;
 891
 892         mutex_lock_nested(&client_mutex, SINGLE_DEPTH_NESTING);
 893         rbdc = rbd_client_find(ceph_opts);
 894         if (rbdc)       /* using an existing client */
 895                 ceph_destroy_options(ceph_opts);
 896         else
 897                 rbdc = rbd_client_create(ceph_opts);
 898         mutex_unlock(&client_mutex);
 899
 900         return rbdc;
 901 }
 902
 903 /*
 904  * Destroy ceph client
 905  *
 906  * Caller must hold rbd_client_list_lock.
 907  */
 908 static void rbd_client_release(struct kref *kref)
 909 {
 910         struct rbd_client *rbdc = container_of(kref, struct rbd_client, kref);
 911
 912         dout("%s: rbdc %p\n", __func__, rbdc);
 913         spin_lock(&rbd_client_list_lock);
 914         list_del(&rbdc->node);
 915         spin_unlock(&rbd_client_list_lock);
 916
 917         ceph_destroy_client(rbdc->client);
 918         kfree(rbdc);
 919 }
 920
 921 /*
 922  * Drop reference to ceph client node. If it's not referenced anymore, release
 923  * it.
 924  */
 925 static void rbd_put_client(struct rbd_client *rbdc)
 926 {
 927         if (rbdc)
 928                 kref_put(&rbdc->kref, rbd_client_release);
 929 }
 930
 931 static bool rbd_image_format_valid(u32 image_format)
 932 {
 933         return image_format == 1 || image_format == 2;
 934 }
 935
 936 static bool rbd_dev_ondisk_valid(struct rbd_image_header_ondisk *ondisk)
 937 {
 938         size_t size;
 939         u32 snap_count;
 940
 941         /* The header has to start with the magic rbd header text */
 942         if (memcmp(&ondisk->text, RBD_HEADER_TEXT, sizeof (RBD_HEADER_TEXT)))
 943                 return false;
 944
 945         /* The bio layer requires at least sector-sized I/O */
 946
 947         if (ondisk->options.order < SECTOR_SHIFT)
 948                 return false;
 949
 950         /* If we use u64 in a few spots we may be able to loosen this */
 951
 952         if (ondisk->options.order > 8 * sizeof (int) - 1)
 953                 return false;
 954
 955         /*
 956          * The size of a snapshot header has to fit in a size_t, and
 957          * that limits the number of snapshots.
 958          */
 959         snap_count = le32_to_cpu(ondisk->snap_count);
 960         size = SIZE_MAX - sizeof (struct ceph_snap_context);
 961         if (snap_count > size / sizeof (__le64))
 962                 return false;
 963
 964         /*
 965          * Not only that, but the size of the entire the snapshot
 966          * header must also be representable in a size_t.
 967          */
 968         size -= snap_count * sizeof (__le64);
 969         if ((u64) size < le64_to_cpu(ondisk->snap_names_len))
 970                 return false;
 971
 972         return true;
 973 }
 974
 975 /*
 976  * returns the size of an object in the image
 977  */
 978 static u32 rbd_obj_bytes(struct rbd_image_header *header)
 979 {
 980         return 1U << header->obj_order;
 981 }
 982
 983 static void rbd_init_layout(struct rbd_device *rbd_dev)
 984 {
 985         if (rbd_dev->header.stripe_unit == 0 ||
 986             rbd_dev->header.stripe_count == 0) {
 987                 rbd_dev->header.stripe_unit = rbd_obj_bytes(&rbd_dev->header);
 988                 rbd_dev->header.stripe_count = 1;
 989         }
 990
 991         rbd_dev->layout.stripe_unit = rbd_dev->header.stripe_unit;
 992         rbd_dev->layout.stripe_count = rbd_dev->header.stripe_count;
 993         rbd_dev->layout.object_size = rbd_obj_bytes(&rbd_dev->header);
 994         rbd_dev->layout.pool_id = rbd_dev->header.data_pool_id == CEPH_NOPOOL ?
 995                           rbd_dev->spec->pool_id : rbd_dev->header.data_pool_id;
 996         RCU_INIT_POINTER(rbd_dev->layout.pool_ns, NULL);
 997 }
 998
 999 /*
1000  * Fill an rbd image header with information from the given format 1
1001  * on-disk header.
1002  */
1003 static int rbd_header_from_disk(struct rbd_device *rbd_dev,
1004                                  struct rbd_image_header_ondisk *ondisk)
1005 {
1006         struct rbd_image_header *header = &rbd_dev->header;
1007         bool first_time = header->object_prefix == NULL;
1008         struct ceph_snap_context *snapc;
1009         char *object_prefix = NULL;
1010         char *snap_names = NULL;
1011         u64 *snap_sizes = NULL;
1012         u32 snap_count;
1013         int ret = -ENOMEM;
1014         u32 i;
1015
1016         /* Allocate this now to avoid having to handle failure below */
1017
1018         if (first_time) {
1019                 object_prefix = kstrndup(ondisk->object_prefix,
1020                                          sizeof(ondisk->object_prefix),
1021                                          GFP_KERNEL);
1022                 if (!object_prefix)
1023                         return -ENOMEM;
1024         }
1025
1026         /* Allocate the snapshot context and fill it in */
1027
1028         snap_count = le32_to_cpu(ondisk->snap_count);
1029         snapc = ceph_create_snap_context(snap_count, GFP_KERNEL);
1030         if (!snapc)
1031                 goto out_err;
1032         snapc->seq = le64_to_cpu(ondisk->snap_seq);
1033         if (snap_count) {
1034                 struct rbd_image_snap_ondisk *snaps;
1035                 u64 snap_names_len = le64_to_cpu(ondisk->snap_names_len);
1036
1037                 /* We'll keep a copy of the snapshot names... */
1038
1039                 if (snap_names_len > (u64)SIZE_MAX)
1040                         goto out_2big;
1041                 snap_names = kmalloc(snap_names_len, GFP_KERNEL);
1042                 if (!snap_names)
1043                         goto out_err;
1044
1045                 /* ...as well as the array of their sizes. */
1046                 snap_sizes = kmalloc_array(snap_count,
1047                                            sizeof(*header->snap_sizes),
1048                                            GFP_KERNEL);
1049                 if (!snap_sizes)
1050                         goto out_err;
1051
1052                 /*
1053                  * Copy the names, and fill in each snapshot's id
1054                  * and size.
1055                  *
1056                  * Note that rbd_dev_v1_header_info() guarantees the
1057                  * ondisk buffer we're working with has
1058                  * snap_names_len bytes beyond the end of the
1059                  * snapshot id array, this memcpy() is safe.
1060                  */
1061                 memcpy(snap_names, &ondisk->snaps[snap_count], snap_names_len);
1062                 snaps = ondisk->snaps;
1063                 for (i = 0; i < snap_count; i++) {
1064                         snapc->snaps[i] = le64_to_cpu(snaps[i].id);
1065                         snap_sizes[i] = le64_to_cpu(snaps[i].image_size);
1066                 }
1067         }
1068
1069         /* We won't fail any more, fill in the header */
1070
1071         if (first_time) {
1072                 header->object_prefix = object_prefix;
1073                 header->obj_order = ondisk->options.order;
1074                 rbd_init_layout(rbd_dev);
1075         } else {
1076                 ceph_put_snap_context(header->snapc);
1077                 kfree(header->snap_names);
1078                 kfree(header->snap_sizes);
1079         }
1080
1081         /* The remaining fields always get updated (when we refresh) */
1082
1083         header->image_size = le64_to_cpu(ondisk->image_size);
1084         header->snapc = snapc;
1085         header->snap_names = snap_names;
1086         header->snap_sizes = snap_sizes;
1087
1088         return 0;
1089 out_2big:
1090         ret = -EIO;
1091 out_err:
1092         kfree(snap_sizes);
1093         kfree(snap_names);
1094         ceph_put_snap_context(snapc);
1095         kfree(object_prefix);
1096
1097         return ret;
1098 }
1099
1100 static const char *_rbd_dev_v1_snap_name(struct rbd_device *rbd_dev, u32 which)
1101 {
1102         const char *snap_name;
1103
1104         rbd_assert(which < rbd_dev->header.snapc->num_snaps);
1105
1106         /* Skip over names until we find the one we are looking for */
1107
1108         snap_name = rbd_dev->header.snap_names;
1109         while (which--)
1110                 snap_name += strlen(snap_name) + 1;
1111
1112         return kstrdup(snap_name, GFP_KERNEL);
1113 }
1114
1115 /*
1116  * Snapshot id comparison function for use with qsort()/bsearch().
1117  * Note that result is for snapshots in *descending* order.
1118  */
1119 static int snapid_compare_reverse(const void *s1, const void *s2)
1120 {
1121         u64 snap_id1 = *(u64 *)s1;
1122         u64 snap_id2 = *(u64 *)s2;
1123
1124         if (snap_id1 < snap_id2)
1125                 return 1;
1126         return snap_id1 == snap_id2 ? 0 : -1;
1127 }
1128
1129 /*
1130  * Search a snapshot context to see if the given snapshot id is
1131  * present.
1132  *
1133  * Returns the position of the snapshot id in the array if it's found,
1134  * or BAD_SNAP_INDEX otherwise.
1135  *
1136  * Note: The snapshot array is in kept sorted (by the osd) in
1137  * reverse order, highest snapshot id first.
1138  */
1139 static u32 rbd_dev_snap_index(struct rbd_device *rbd_dev, u64 snap_id)
1140 {
1141         struct ceph_snap_context *snapc = rbd_dev->header.snapc;
1142         u64 *found;
1143
1144         found = bsearch(&snap_id, &snapc->snaps, snapc->num_snaps,
1145                                 sizeof (snap_id), snapid_compare_reverse);
1146
1147         return found ? (u32)(found - &snapc->snaps[0]) : BAD_SNAP_INDEX;
1148 }
1149
1150 static const char *rbd_dev_v1_snap_name(struct rbd_device *rbd_dev,
1151                                         u64 snap_id)
1152 {
1153         u32 which;
1154         const char *snap_name;
1155
1156         which = rbd_dev_snap_index(rbd_dev, snap_id);
1157         if (which == BAD_SNAP_INDEX)
1158                 return ERR_PTR(-ENOENT);
1159
1160         snap_name = _rbd_dev_v1_snap_name(rbd_dev, which);
1161         return snap_name ? snap_name : ERR_PTR(-ENOMEM);
1162 }
1163
1164 static const char *rbd_snap_name(struct rbd_device *rbd_dev, u64 snap_id)
1165 {
1166         if (snap_id == CEPH_NOSNAP)
1167                 return RBD_SNAP_HEAD_NAME;
1168
1169         rbd_assert(rbd_image_format_valid(rbd_dev->image_format));
1170         if (rbd_dev->image_format == 1)
1171                 return rbd_dev_v1_snap_name(rbd_dev, snap_id);
1172
1173         return rbd_dev_v2_snap_name(rbd_dev, snap_id);
1174 }
1175
1176 static int rbd_snap_size(struct rbd_device *rbd_dev, u64 snap_id,
1177                                 u64 *snap_size)
1178 {
1179         rbd_assert(rbd_image_format_valid(rbd_dev->image_format));
1180         if (snap_id == CEPH_NOSNAP) {
1181                 *snap_size = rbd_dev->header.image_size;
1182         } else if (rbd_dev->image_format == 1) {
1183                 u32 which;
1184
1185                 which = rbd_dev_snap_index(rbd_dev, snap_id);
1186                 if (which == BAD_SNAP_INDEX)
1187                         return -ENOENT;
1188
1189                 *snap_size = rbd_dev->header.snap_sizes[which];
1190         } else {
1191                 u64 size = 0;
1192                 int ret;
1193
1194                 ret = _rbd_dev_v2_snap_size(rbd_dev, snap_id, NULL, &size);
1195                 if (ret)
1196                         return ret;
1197
1198                 *snap_size = size;
1199         }
1200         return 0;
1201 }
1202
1203 static int rbd_snap_features(struct rbd_device *rbd_dev, u64 snap_id,
1204                         u64 *snap_features)
1205 {
1206         rbd_assert(rbd_image_format_valid(rbd_dev->image_format));
1207         if (snap_id == CEPH_NOSNAP) {
1208                 *snap_features = rbd_dev->header.features;
1209         } else if (rbd_dev->image_format == 1) {
1210                 *snap_features = 0;     /* No features for format 1 */
1211         } else {
1212                 u64 features = 0;
1213                 int ret;
1214
1215                 ret = _rbd_dev_v2_snap_features(rbd_dev, snap_id, &features);
1216                 if (ret)
1217                         return ret;
1218
1219                 *snap_features = features;
1220         }
1221         return 0;
1222 }
1223
1224 static int rbd_dev_mapping_set(struct rbd_device *rbd_dev)
1225 {
1226         u64 snap_id = rbd_dev->spec->snap_id;
1227         u64 size = 0;
1228         u64 features = 0;
1229         int ret;
1230
1231         ret = rbd_snap_size(rbd_dev, snap_id, &size);
1232         if (ret)
1233                 return ret;
1234         ret = rbd_snap_features(rbd_dev, snap_id, &features);
1235         if (ret)
1236                 return ret;
1237
1238         rbd_dev->mapping.size = size;
1239         rbd_dev->mapping.features = features;
1240
1241         return 0;
1242 }
1243
1244 static void rbd_dev_mapping_clear(struct rbd_device *rbd_dev)
1245 {
1246         rbd_dev->mapping.size = 0;
1247         rbd_dev->mapping.features = 0;
1248 }
1249
1250 static u64 rbd_segment_offset(struct rbd_device *rbd_dev, u64 offset)
1251 {
1252         u64 segment_size = rbd_obj_bytes(&rbd_dev->header);
1253
1254         return offset & (segment_size - 1);
1255 }
1256
1257 static u64 rbd_segment_length(struct rbd_device *rbd_dev,
1258                                 u64 offset, u64 length)
1259 {
1260         u64 segment_size = rbd_obj_bytes(&rbd_dev->header);
1261
1262         offset &= segment_size - 1;
1263
1264         rbd_assert(length <= U64_MAX - offset);
1265         if (offset + length > segment_size)
1266                 length = segment_size - offset;
1267
1268         return length;
1269 }
1270
1271 /*
1272  * bio helpers
1273  */
1274
1275 static void bio_chain_put(struct bio *chain)
1276 {
1277         struct bio *tmp;
1278
1279         while (chain) {
1280                 tmp = chain;
1281                 chain = chain->bi_next;
1282                 bio_put(tmp);
1283         }
1284 }
1285
1286 /*
1287  * zeros a bio chain, starting at specific offset
1288  */
1289 static void zero_bio_chain(struct bio *chain, int start_ofs)
1290 {
1291         struct bio_vec bv;
1292         struct bvec_iter iter;
1293         unsigned long flags;
1294         void *buf;
1295         int pos = 0;
1296
1297         while (chain) {
1298                 bio_for_each_segment(bv, chain, iter) {
1299                         if (pos + bv.bv_len > start_ofs) {
1300                                 int remainder = max(start_ofs - pos, 0);
1301                                 buf = bvec_kmap_irq(&bv, &flags);
1302                                 memset(buf + remainder, 0,
1303                                        bv.bv_len - remainder);
1304                                 flush_dcache_page(bv.bv_page);
1305                                 bvec_kunmap_irq(buf, &flags);
1306                         }
1307                         pos += bv.bv_len;
1308                 }
1309
1310                 chain = chain->bi_next;
1311         }
1312 }
1313
1314 /*
1315  * similar to zero_bio_chain(), zeros data defined by a page array,
1316  * starting at the given byte offset from the start of the array and
1317  * continuing up to the given end offset.  The pages array is
1318  * assumed to be big enough to hold all bytes up to the end.
1319  */
1320 static void zero_pages(struct page **pages, u64 offset, u64 end)
1321 {
1322         struct page **page = &pages[offset >> PAGE_SHIFT];
1323
1324         rbd_assert(end > offset);
1325         rbd_assert(end - offset <= (u64)SIZE_MAX);
1326         while (offset < end) {
1327                 size_t page_offset;
1328                 size_t length;
1329                 unsigned long flags;
1330                 void *kaddr;
1331
1332                 page_offset = offset & ~PAGE_MASK;
1333                 length = min_t(size_t, PAGE_SIZE - page_offset, end - offset);
1334                 local_irq_save(flags);
1335                 kaddr = kmap_atomic(*page);
1336                 memset(kaddr + page_offset, 0, length);
1337                 flush_dcache_page(*page);
1338                 kunmap_atomic(kaddr);
1339                 local_irq_restore(flags);
1340
1341                 offset += length;
1342                 page++;
1343         }
1344 }
1345
1346 /*
1347  * Clone a portion of a bio, starting at the given byte offset
1348  * and continuing for the number of bytes indicated.
1349  */
1350 static struct bio *bio_clone_range(struct bio *bio_src,
1351                                         unsigned int offset,
1352                                         unsigned int len,
1353                                         gfp_t gfpmask)
1354 {
1355         struct bio *bio;
1356
1357         bio = bio_clone(bio_src, gfpmask);
1358         if (!bio)
1359                 return NULL;    /* ENOMEM */
1360
1361         bio_advance(bio, offset);
1362         bio->bi_iter.bi_size = len;
1363
1364         return bio;
1365 }
1366
1367 /*
1368  * Clone a portion of a bio chain, starting at the given byte offset
1369  * into the first bio in the source chain and continuing for the
1370  * number of bytes indicated.  The result is another bio chain of
1371  * exactly the given length, or a null pointer on error.
1372  *
1373  * The bio_src and offset parameters are both in-out.  On entry they
1374  * refer to the first source bio and the offset into that bio where
1375  * the start of data to be cloned is located.
1376  *
1377  * On return, bio_src is updated to refer to the bio in the source
1378  * chain that contains first un-cloned byte, and *offset will
1379  * contain the offset of that byte within that bio.
1380  */
1381 static struct bio *bio_chain_clone_range(struct bio **bio_src,
1382                                         unsigned int *offset,
1383                                         unsigned int len,
1384                                         gfp_t gfpmask)
1385 {
1386         struct bio *bi = *bio_src;
1387         unsigned int off = *offset;
1388         struct bio *chain = NULL;
1389         struct bio **end;
1390
1391         /* Build up a chain of clone bios up to the limit */
1392
1393         if (!bi || off >= bi->bi_iter.bi_size || !len)
1394                 return NULL;            /* Nothing to clone */
1395
1396         end = &chain;
1397         while (len) {
1398                 unsigned int bi_size;
1399                 struct bio *bio;
1400
1401                 if (!bi) {
1402                         rbd_warn(NULL, "bio_chain exhausted with %u left", len);
1403                         goto out_err;   /* EINVAL; ran out of bio's */
1404                 }
1405                 bi_size = min_t(unsigned int, bi->bi_iter.bi_size - off, len);
1406                 bio = bio_clone_range(bi, off, bi_size, gfpmask);
1407                 if (!bio)
1408                         goto out_err;   /* ENOMEM */
1409
1410                 *end = bio;
1411                 end = &bio->bi_next;
1412
1413                 off += bi_size;
1414                 if (off == bi->bi_iter.bi_size) {
1415                         bi = bi->bi_next;
1416                         off = 0;
1417                 }
1418                 len -= bi_size;
1419         }
1420         *bio_src = bi;
1421         *offset = off;
1422
1423         return chain;
1424 out_err:
1425         bio_chain_put(chain);
1426
1427         return NULL;
1428 }
1429
1430 /*
1431  * The default/initial value for all object request flags is 0.  For
1432  * each flag, once its value is set to 1 it is never reset to 0
1433  * again.
1434  */
1435 static void obj_request_img_data_set(struct rbd_obj_request *obj_request)
1436 {
1437         if (test_and_set_bit(OBJ_REQ_IMG_DATA, &obj_request->flags)) {
1438                 struct rbd_device *rbd_dev;
1439
1440                 rbd_dev = obj_request->img_request->rbd_dev;
1441                 rbd_warn(rbd_dev, "obj_request %p already marked img_data",
1442                         obj_request);
1443         }
1444 }
1445
1446 static bool obj_request_img_data_test(struct rbd_obj_request *obj_request)
1447 {
1448         smp_mb();
1449         return test_bit(OBJ_REQ_IMG_DATA, &obj_request->flags) != 0;
1450 }
1451
1452 static void obj_request_done_set(struct rbd_obj_request *obj_request)
1453 {
1454         if (test_and_set_bit(OBJ_REQ_DONE, &obj_request->flags)) {
1455                 struct rbd_device *rbd_dev = NULL;
1456
1457                 if (obj_request_img_data_test(obj_request))
1458                         rbd_dev = obj_request->img_request->rbd_dev;
1459                 rbd_warn(rbd_dev, "obj_request %p already marked done",
1460                         obj_request);
1461         }
1462 }
1463
1464 static bool obj_request_done_test(struct rbd_obj_request *obj_request)
1465 {
1466         smp_mb();
1467         return test_bit(OBJ_REQ_DONE, &obj_request->flags) != 0;
1468 }
1469
1470 /*
1471  * This sets the KNOWN flag after (possibly) setting the EXISTS
1472  * flag.  The latter is set based on the "exists" value provided.
1473  *
1474  * Note that for our purposes once an object exists it never goes
1475  * away again.  It's possible that the response from two existence
1476  * checks are separated by the creation of the target object, and
1477  * the first ("doesn't exist") response arrives *after* the second
1478  * ("does exist").  In that case we ignore the second one.
1479  */
1480 static void obj_request_existence_set(struct rbd_obj_request *obj_request,
1481                                 bool exists)
1482 {
1483         if (exists)
1484                 set_bit(OBJ_REQ_EXISTS, &obj_request->flags);
1485         set_bit(OBJ_REQ_KNOWN, &obj_request->flags);
1486         smp_mb();
1487 }
1488
1489 static bool obj_request_known_test(struct rbd_obj_request *obj_request)
1490 {
1491         smp_mb();
1492         return test_bit(OBJ_REQ_KNOWN, &obj_request->flags) != 0;
1493 }
1494
1495 static bool obj_request_exists_test(struct rbd_obj_request *obj_request)
1496 {
1497         smp_mb();
1498         return test_bit(OBJ_REQ_EXISTS, &obj_request->flags) != 0;
1499 }
1500
1501 static bool obj_request_overlaps_parent(struct rbd_obj_request *obj_request)
1502 {
1503         struct rbd_device *rbd_dev = obj_request->img_request->rbd_dev;
1504
1505         return obj_request->img_offset <
1506             round_up(rbd_dev->parent_overlap, rbd_obj_bytes(&rbd_dev->header));
1507 }
1508
1509 static void rbd_obj_request_get(struct rbd_obj_request *obj_request)
1510 {
1511         dout("%s: obj %p (was %d)\n", __func__, obj_request,
1512                 kref_read(&obj_request->kref));
1513         kref_get(&obj_request->kref);
1514 }
1515
1516 static void rbd_obj_request_destroy(struct kref *kref);
1517 static void rbd_obj_request_put(struct rbd_obj_request *obj_request)
1518 {
1519         rbd_assert(obj_request != NULL);
1520         dout("%s: obj %p (was %d)\n", __func__, obj_request,
1521                 kref_read(&obj_request->kref));
1522         kref_put(&obj_request->kref, rbd_obj_request_destroy);
1523 }
1524
1525 static void rbd_img_request_get(struct rbd_img_request *img_request)
1526 {
1527         dout("%s: img %p (was %d)\n", __func__, img_request,
1528              kref_read(&img_request->kref));
1529         kref_get(&img_request->kref);
1530 }
1531
1532 static bool img_request_child_test(struct rbd_img_request *img_request);
1533 static void rbd_parent_request_destroy(struct kref *kref);
1534 static void rbd_img_request_destroy(struct kref *kref);
1535 static void rbd_img_request_put(struct rbd_img_request *img_request)
1536 {
1537         rbd_assert(img_request != NULL);
1538         dout("%s: img %p (was %d)\n", __func__, img_request,
1539                 kref_read(&img_request->kref));
1540         if (img_request_child_test(img_request))
1541                 kref_put(&img_request->kref, rbd_parent_request_destroy);
1542         else
1543                 kref_put(&img_request->kref, rbd_img_request_destroy);
1544 }
1545
1546 static inline void rbd_img_obj_request_add(struct rbd_img_request *img_request,
1547                                         struct rbd_obj_request *obj_request)
1548 {
1549         rbd_assert(obj_request->img_request == NULL);
1550
1551         /* Image request now owns object's original reference */
1552         obj_request->img_request = img_request;
1553         obj_request->which = img_request->obj_request_count;
1554         rbd_assert(!obj_request_img_data_test(obj_request));
1555         obj_request_img_data_set(obj_request);
1556         rbd_assert(obj_request->which != BAD_WHICH);
1557         img_request->obj_request_count++;
1558         list_add_tail(&obj_request->links, &img_request->obj_requests);
1559         dout("%s: img %p obj %p w=%u\n", __func__, img_request, obj_request,
1560                 obj_request->which);
1561 }
1562
1563 static inline void rbd_img_obj_request_del(struct rbd_img_request *img_request,
1564                                         struct rbd_obj_request *obj_request)
1565 {
1566         rbd_assert(obj_request->which != BAD_WHICH);
1567
1568         dout("%s: img %p obj %p w=%u\n", __func__, img_request, obj_request,
1569                 obj_request->which);
1570         list_del(&obj_request->links);
1571         rbd_assert(img_request->obj_request_count > 0);
1572         img_request->obj_request_count--;
1573         rbd_assert(obj_request->which == img_request->obj_request_count);
1574         obj_request->which = BAD_WHICH;
1575         rbd_assert(obj_request_img_data_test(obj_request));
1576         rbd_assert(obj_request->img_request == img_request);
1577         obj_request->img_request = NULL;
1578         obj_request->callback = NULL;
1579         rbd_obj_request_put(obj_request);
1580 }
1581
1582 static bool obj_request_type_valid(enum obj_request_type type)
1583 {
1584         switch (type) {
1585         case OBJ_REQUEST_NODATA:
1586         case OBJ_REQUEST_BIO:
1587         case OBJ_REQUEST_PAGES:
1588                 return true;
1589         default:
1590                 return false;
1591         }
1592 }
1593
1594 static void rbd_img_obj_callback(struct rbd_obj_request *obj_request);
1595
1596 static void rbd_obj_request_submit(struct rbd_obj_request *obj_request)
1597 {
1598         struct ceph_osd_request *osd_req = obj_request->osd_req;
1599
1600         dout("%s %p object_no %016llx %llu~%llu osd_req %p\n", __func__,
1601              obj_request, obj_request->object_no, obj_request->offset,
1602              obj_request->length, osd_req);
1603         if (obj_request_img_data_test(obj_request)) {
1604                 WARN_ON(obj_request->callback != rbd_img_obj_callback);
1605                 rbd_img_request_get(obj_request->img_request);
1606         }
1607         ceph_osdc_start_request(osd_req->r_osdc, osd_req, false);
1608 }
1609
1610 static void rbd_img_request_complete(struct rbd_img_request *img_request)
1611 {
1612
1613         dout("%s: img %p\n", __func__, img_request);
1614
1615         /*
1616          * If no error occurred, compute the aggregate transfer
1617          * count for the image request.  We could instead use
1618          * atomic64_cmpxchg() to update it as each object request
1619          * completes; not clear which way is better off hand.
1620          */
1621         if (!img_request->result) {
1622                 struct rbd_obj_request *obj_request;
1623                 u64 xferred = 0;
1624
1625                 for_each_obj_request(img_request, obj_request)
1626                         xferred += obj_request->xferred;
1627                 img_request->xferred = xferred;
1628         }
1629
1630         if (img_request->callback)
1631                 img_request->callback(img_request);
1632         else
1633                 rbd_img_request_put(img_request);
1634 }
1635
1636 /*
1637  * The default/initial value for all image request flags is 0.  Each
1638  * is conditionally set to 1 at image request initialization time
1639  * and currently never change thereafter.
1640  */
1641 static void img_request_write_set(struct rbd_img_request *img_request)
1642 {
1643         set_bit(IMG_REQ_WRITE, &img_request->flags);
1644         smp_mb();
1645 }
1646
1647 static bool img_request_write_test(struct rbd_img_request *img_request)
1648 {
1649         smp_mb();
1650         return test_bit(IMG_REQ_WRITE, &img_request->flags) != 0;
1651 }
1652
1653 /*
1654  * Set the discard flag when the img_request is an discard request
1655  */
1656 static void img_request_discard_set(struct rbd_img_request *img_request)
1657 {
1658         set_bit(IMG_REQ_DISCARD, &img_request->flags);
1659         smp_mb();
1660 }
1661
1662 static bool img_request_discard_test(struct rbd_img_request *img_request)
1663 {
1664         smp_mb();
1665         return test_bit(IMG_REQ_DISCARD, &img_request->flags) != 0;
1666 }
1667
1668 static void img_request_child_set(struct rbd_img_request *img_request)
1669 {
1670         set_bit(IMG_REQ_CHILD, &img_request->flags);
1671         smp_mb();
1672 }
1673
1674 static void img_request_child_clear(struct rbd_img_request *img_request)
1675 {
1676         clear_bit(IMG_REQ_CHILD, &img_request->flags);
1677         smp_mb();
1678 }
1679
1680 static bool img_request_child_test(struct rbd_img_request *img_request)
1681 {
1682         smp_mb();
1683         return test_bit(IMG_REQ_CHILD, &img_request->flags) != 0;
1684 }
1685
1686 static void img_request_layered_set(struct rbd_img_request *img_request)
1687 {
1688         set_bit(IMG_REQ_LAYERED, &img_request->flags);
1689         smp_mb();
1690 }
1691
1692 static void img_request_layered_clear(struct rbd_img_request *img_request)
1693 {
1694         clear_bit(IMG_REQ_LAYERED, &img_request->flags);
1695         smp_mb();
1696 }
1697
1698 static bool img_request_layered_test(struct rbd_img_request *img_request)
1699 {
1700         smp_mb();
1701         return test_bit(IMG_REQ_LAYERED, &img_request->flags) != 0;
1702 }
1703
1704 static enum obj_operation_type
1705 rbd_img_request_op_type(struct rbd_img_request *img_request)
1706 {
1707         if (img_request_write_test(img_request))
1708                 return OBJ_OP_WRITE;
1709         else if (img_request_discard_test(img_request))
1710                 return OBJ_OP_DISCARD;
1711         else
1712                 return OBJ_OP_READ;
1713 }
1714
1715 static void
1716 rbd_img_obj_request_read_callback(struct rbd_obj_request *obj_request)
1717 {
1718         u64 xferred = obj_request->xferred;
1719         u64 length = obj_request->length;
1720
1721         dout("%s: obj %p img %p result %d %llu/%llu\n", __func__,
1722                 obj_request, obj_request->img_request, obj_request->result,
1723                 xferred, length);
1724         /*
1725          * ENOENT means a hole in the image.  We zero-fill the entire
1726          * length of the request.  A short read also implies zero-fill
1727          * to the end of the request.  An error requires the whole
1728          * length of the request to be reported finished with an error
1729          * to the block layer.  In each case we update the xferred
1730          * count to indicate the whole request was satisfied.
1731          */
1732         rbd_assert(obj_request->type != OBJ_REQUEST_NODATA);
1733         if (obj_request->result == -ENOENT) {
1734                 if (obj_request->type == OBJ_REQUEST_BIO)
1735                         zero_bio_chain(obj_request->bio_list, 0);
1736                 else
1737                         zero_pages(obj_request->pages, 0, length);
1738                 obj_request->result = 0;
1739         } else if (xferred < length && !obj_request->result) {
1740                 if (obj_request->type == OBJ_REQUEST_BIO)
1741                         zero_bio_chain(obj_request->bio_list, xferred);
1742                 else
1743                         zero_pages(obj_request->pages, xferred, length);
1744         }
1745         obj_request->xferred = length;
1746         obj_request_done_set(obj_request);
1747 }
1748
1749 static void rbd_obj_request_complete(struct rbd_obj_request *obj_request)
1750 {
1751         dout("%s: obj %p cb %p\n", __func__, obj_request,
1752                 obj_request->callback);
1753         if (obj_request->callback)
1754                 obj_request->callback(obj_request);
1755         else
1756                 complete_all(&obj_request->completion);
1757 }
1758
1759 static void rbd_obj_request_error(struct rbd_obj_request *obj_request, int err)
1760 {
1761         obj_request->result = err;
1762         obj_request->xferred = 0;
1763         /*
1764          * kludge - mirror rbd_obj_request_submit() to match a put in
1765          * rbd_img_obj_callback()
1766          */
1767         if (obj_request_img_data_test(obj_request)) {
1768                 WARN_ON(obj_request->callback != rbd_img_obj_callback);
1769                 rbd_img_request_get(obj_request->img_request);
1770         }
1771         obj_request_done_set(obj_request);
1772         rbd_obj_request_complete(obj_request);
1773 }
1774
1775 static void rbd_osd_read_callback(struct rbd_obj_request *obj_request)
1776 {
1777         struct rbd_img_request *img_request = NULL;
1778         struct rbd_device *rbd_dev = NULL;
1779         bool layered = false;
1780
1781         if (obj_request_img_data_test(obj_request)) {
1782                 img_request = obj_request->img_request;
1783                 layered = img_request && img_request_layered_test(img_request);
1784                 rbd_dev = img_request->rbd_dev;
1785         }
1786
1787         dout("%s: obj %p img %p result %d %llu/%llu\n", __func__,
1788                 obj_request, img_request, obj_request->result,
1789                 obj_request->xferred, obj_request->length);
1790         if (layered && obj_request->result == -ENOENT &&
1791                         obj_request->img_offset < rbd_dev->parent_overlap)
1792                 rbd_img_parent_read(obj_request);
1793         else if (img_request)
1794                 rbd_img_obj_request_read_callback(obj_request);
1795         else
1796                 obj_request_done_set(obj_request);
1797 }
1798
1799 static void rbd_osd_write_callback(struct rbd_obj_request *obj_request)
1800 {
1801         dout("%s: obj %p result %d %llu\n", __func__, obj_request,
1802                 obj_request->result, obj_request->length);
1803         /*
1804          * There is no such thing as a successful short write.  Set
1805          * it to our originally-requested length.
1806          */
1807         obj_request->xferred = obj_request->length;
1808         obj_request_done_set(obj_request);
1809 }
1810
1811 static void rbd_osd_discard_callback(struct rbd_obj_request *obj_request)
1812 {
1813         dout("%s: obj %p result %d %llu\n", __func__, obj_request,
1814                 obj_request->result, obj_request->length);
1815         /*
1816          * There is no such thing as a successful short discard.  Set
1817          * it to our originally-requested length.
1818          */
1819         obj_request->xferred = obj_request->length;
1820         /* discarding a non-existent object is not a problem */
1821         if (obj_request->result == -ENOENT)
1822                 obj_request->result = 0;
1823         obj_request_done_set(obj_request);
1824 }
1825
1826 /*
1827  * For a simple stat call there's nothing to do.  We'll do more if
1828  * this is part of a write sequence for a layered image.
1829  */
1830 static void rbd_osd_stat_callback(struct rbd_obj_request *obj_request)
1831 {
1832         dout("%s: obj %p\n", __func__, obj_request);
1833         obj_request_done_set(obj_request);
1834 }
1835
1836 static void rbd_osd_call_callback(struct rbd_obj_request *obj_request)
1837 {
1838         dout("%s: obj %p\n", __func__, obj_request);
1839
1840         if (obj_request_img_data_test(obj_request))
1841                 rbd_osd_copyup_callback(obj_request);
1842         else
1843                 obj_request_done_set(obj_request);
1844 }
1845
1846 static void rbd_osd_req_callback(struct ceph_osd_request *osd_req)
1847 {
1848         struct rbd_obj_request *obj_request = osd_req->r_priv;
1849         u16 opcode;
1850
1851         dout("%s: osd_req %p\n", __func__, osd_req);
1852         rbd_assert(osd_req == obj_request->osd_req);
1853         if (obj_request_img_data_test(obj_request)) {
1854                 rbd_assert(obj_request->img_request);
1855                 rbd_assert(obj_request->which != BAD_WHICH);
1856         } else {
1857                 rbd_assert(obj_request->which == BAD_WHICH);
1858         }
1859
1860         if (osd_req->r_result < 0)
1861                 obj_request->result = osd_req->r_result;
1862
1863         /*
1864          * We support a 64-bit length, but ultimately it has to be
1865          * passed to the block layer, which just supports a 32-bit
1866          * length field.
1867          */
1868         obj_request->xferred = osd_req->r_ops[0].outdata_len;
1869         rbd_assert(obj_request->xferred < (u64)UINT_MAX);
1870
1871         opcode = osd_req->r_ops[0].op;
1872         switch (opcode) {
1873         case CEPH_OSD_OP_READ:
1874                 rbd_osd_read_callback(obj_request);
1875                 break;
1876         case CEPH_OSD_OP_SETALLOCHINT:
1877                 rbd_assert(osd_req->r_ops[1].op == CEPH_OSD_OP_WRITE ||
1878                            osd_req->r_ops[1].op == CEPH_OSD_OP_WRITEFULL);
1879                 /* fall through */
1880         case CEPH_OSD_OP_WRITE:
1881         case CEPH_OSD_OP_WRITEFULL:
1882                 rbd_osd_write_callback(obj_request);
1883                 break;
1884         case CEPH_OSD_OP_STAT:
1885                 rbd_osd_stat_callback(obj_request);
1886                 break;
1887         case CEPH_OSD_OP_DELETE:
1888         case CEPH_OSD_OP_TRUNCATE:
1889         case CEPH_OSD_OP_ZERO:
1890                 rbd_osd_discard_callback(obj_request);
1891                 break;
1892         case CEPH_OSD_OP_CALL:
1893                 rbd_osd_call_callback(obj_request);
1894                 break;
1895         default:
1896                 rbd_warn(NULL, "unexpected OSD op: object_no %016llx opcode %d",
1897                          obj_request->object_no, opcode);
1898                 break;
1899         }
1900
1901         if (obj_request_done_test(obj_request))
1902                 rbd_obj_request_complete(obj_request);
1903 }
1904
1905 static void rbd_osd_req_format_read(struct rbd_obj_request *obj_request)
1906 {
1907         struct ceph_osd_request *osd_req = obj_request->osd_req;
1908
1909         rbd_assert(obj_request_img_data_test(obj_request));
1910         osd_req->r_snapid = obj_request->img_request->snap_id;
1911 }
1912
1913 static void rbd_osd_req_format_write(struct rbd_obj_request *obj_request)
1914 {
1915         struct ceph_osd_request *osd_req = obj_request->osd_req;
1916
1917         osd_req->r_mtime = CURRENT_TIME;
1918         osd_req->r_data_offset = obj_request->offset;
1919 }
1920
1921 static struct ceph_osd_request *
1922 __rbd_osd_req_create(struct rbd_device *rbd_dev,
1923                      struct ceph_snap_context *snapc,
1924                      int num_ops, unsigned int flags,
1925                      struct rbd_obj_request *obj_request)
1926 {
1927         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
1928         struct ceph_osd_request *req;
1929         const char *name_format = rbd_dev->image_format == 1 ?
1930                                       RBD_V1_DATA_FORMAT : RBD_V2_DATA_FORMAT;
1931
1932         req = ceph_osdc_alloc_request(osdc, snapc, num_ops, false, GFP_NOIO);
1933         if (!req)
1934                 return NULL;
1935
1936         req->r_flags = flags;
1937         req->r_callback = rbd_osd_req_callback;
1938         req->r_priv = obj_request;
1939
1940         req->r_base_oloc.pool = rbd_dev->layout.pool_id;
1941         if (ceph_oid_aprintf(&req->r_base_oid, GFP_NOIO, name_format,
1942                         rbd_dev->header.object_prefix, obj_request->object_no))
1943                 goto err_req;
1944
1945         if (ceph_osdc_alloc_messages(req, GFP_NOIO))
1946                 goto err_req;
1947
1948         return req;
1949
1950 err_req:
1951         ceph_osdc_put_request(req);
1952         return NULL;
1953 }
1954
1955 /*
1956  * Create an osd request.  A read request has one osd op (read).
1957  * A write request has either one (watch) or two (hint+write) osd ops.
1958  * (All rbd data writes are prefixed with an allocation hint op, but
1959  * technically osd watch is a write request, hence this distinction.)
1960  */
1961 static struct ceph_osd_request *rbd_osd_req_create(
1962                                         struct rbd_device *rbd_dev,
1963                                         enum obj_operation_type op_type,
1964                                         unsigned int num_ops,
1965                                         struct rbd_obj_request *obj_request)
1966 {
1967         struct ceph_snap_context *snapc = NULL;
1968
1969         if (obj_request_img_data_test(obj_request) &&
1970                 (op_type == OBJ_OP_DISCARD || op_type == OBJ_OP_WRITE)) {
1971                 struct rbd_img_request *img_request = obj_request->img_request;
1972                 if (op_type == OBJ_OP_WRITE) {
1973                         rbd_assert(img_request_write_test(img_request));
1974                 } else {
1975                         rbd_assert(img_request_discard_test(img_request));
1976                 }
1977                 snapc = img_request->snapc;
1978         }
1979
1980         rbd_assert(num_ops == 1 || ((op_type == OBJ_OP_WRITE) && num_ops == 2));
1981
1982         return __rbd_osd_req_create(rbd_dev, snapc, num_ops,
1983             (op_type == OBJ_OP_WRITE || op_type == OBJ_OP_DISCARD) ?
1984             CEPH_OSD_FLAG_WRITE : CEPH_OSD_FLAG_READ, obj_request);
1985 }
1986
1987 /*
1988  * Create a copyup osd request based on the information in the object
1989  * request supplied.  A copyup request has two or three osd ops, a
1990  * copyup method call, potentially a hint op, and a write or truncate
1991  * or zero op.
1992  */
1993 static struct ceph_osd_request *
1994 rbd_osd_req_create_copyup(struct rbd_obj_request *obj_request)
1995 {
1996         struct rbd_img_request *img_request;
1997         int num_osd_ops = 3;
1998
1999         rbd_assert(obj_request_img_data_test(obj_request));
2000         img_request = obj_request->img_request;
2001         rbd_assert(img_request);
2002         rbd_assert(img_request_write_test(img_request) ||
2003                         img_request_discard_test(img_request));
2004
2005         if (img_request_discard_test(img_request))
2006                 num_osd_ops = 2;
2007
2008         return __rbd_osd_req_create(img_request->rbd_dev,
2009                                     img_request->snapc, num_osd_ops,
2010                                     CEPH_OSD_FLAG_WRITE, obj_request);
2011 }
2012
2013 static void rbd_osd_req_destroy(struct ceph_osd_request *osd_req)
2014 {
2015         ceph_osdc_put_request(osd_req);
2016 }
2017
2018 static struct rbd_obj_request *
2019 rbd_obj_request_create(enum obj_request_type type)
2020 {
2021         struct rbd_obj_request *obj_request;
2022
2023         rbd_assert(obj_request_type_valid(type));
2024
2025         obj_request = kmem_cache_zalloc(rbd_obj_request_cache, GFP_NOIO);
2026         if (!obj_request)
2027                 return NULL;
2028
2029         obj_request->which = BAD_WHICH;
2030         obj_request->type = type;
2031         INIT_LIST_HEAD(&obj_request->links);
2032         init_completion(&obj_request->completion);
2033         kref_init(&obj_request->kref);
2034
2035         dout("%s %p\n", __func__, obj_request);
2036         return obj_request;
2037 }
2038
2039 static void rbd_obj_request_destroy(struct kref *kref)
2040 {
2041         struct rbd_obj_request *obj_request;
2042
2043         obj_request = container_of(kref, struct rbd_obj_request, kref);
2044
2045         dout("%s: obj %p\n", __func__, obj_request);
2046
2047         rbd_assert(obj_request->img_request == NULL);
2048         rbd_assert(obj_request->which == BAD_WHICH);
2049
2050         if (obj_request->osd_req)
2051                 rbd_osd_req_destroy(obj_request->osd_req);
2052
2053         rbd_assert(obj_request_type_valid(obj_request->type));
2054         switch (obj_request->type) {
2055         case OBJ_REQUEST_NODATA:
2056                 break;          /* Nothing to do */
2057         case OBJ_REQUEST_BIO:
2058                 if (obj_request->bio_list)
2059                         bio_chain_put(obj_request->bio_list);
2060                 break;
2061         case OBJ_REQUEST_PAGES:
2062                 /* img_data requests don't own their page array */
2063                 if (obj_request->pages &&
2064                     !obj_request_img_data_test(obj_request))
2065                         ceph_release_page_vector(obj_request->pages,
2066                                                 obj_request->page_count);
2067                 break;
2068         }
2069
2070         kmem_cache_free(rbd_obj_request_cache, obj_request);
2071 }
2072
2073 /* It's OK to call this for a device with no parent */
2074
2075 static void rbd_spec_put(struct rbd_spec *spec);
2076 static void rbd_dev_unparent(struct rbd_device *rbd_dev)
2077 {
2078         rbd_dev_remove_parent(rbd_dev);
2079         rbd_spec_put(rbd_dev->parent_spec);
2080         rbd_dev->parent_spec = NULL;
2081         rbd_dev->parent_overlap = 0;
2082 }
2083
2084 /*
2085  * Parent image reference counting is used to determine when an
2086  * image's parent fields can be safely torn down--after there are no
2087  * more in-flight requests to the parent image.  When the last
2088  * reference is dropped, cleaning them up is safe.
2089  */
2090 static void rbd_dev_parent_put(struct rbd_device *rbd_dev)
2091 {
2092         int counter;
2093
2094         if (!rbd_dev->parent_spec)
2095                 return;
2096
2097         counter = atomic_dec_return_safe(&rbd_dev->parent_ref);
2098         if (counter > 0)
2099                 return;
2100
2101         /* Last reference; clean up parent data structures */
2102
2103         if (!counter)
2104                 rbd_dev_unparent(rbd_dev);
2105         else
2106                 rbd_warn(rbd_dev, "parent reference underflow");
2107 }
2108
2109 /*
2110  * If an image has a non-zero parent overlap, get a reference to its
2111  * parent.
2112  *
2113  * Returns true if the rbd device has a parent with a non-zero
2114  * overlap and a reference for it was successfully taken, or
2115  * false otherwise.
2116  */
2117 static bool rbd_dev_parent_get(struct rbd_device *rbd_dev)
2118 {
2119         int counter = 0;
2120
2121         if (!rbd_dev->parent_spec)
2122                 return false;
2123
2124         down_read(&rbd_dev->header_rwsem);
2125         if (rbd_dev->parent_overlap)
2126                 counter = atomic_inc_return_safe(&rbd_dev->parent_ref);
2127         up_read(&rbd_dev->header_rwsem);
2128
2129         if (counter < 0)
2130                 rbd_warn(rbd_dev, "parent reference overflow");
2131
2132         return counter > 0;
2133 }
2134
2135 /*
2136  * Caller is responsible for filling in the list of object requests
2137  * that comprises the image request, and the Linux request pointer
2138  * (if there is one).
2139  */
2140 static struct rbd_img_request *rbd_img_request_create(
2141                                         struct rbd_device *rbd_dev,
2142                                         u64 offset, u64 length,
2143                                         enum obj_operation_type op_type,
2144                                         struct ceph_snap_context *snapc)
2145 {
2146         struct rbd_img_request *img_request;
2147
2148         img_request = kmem_cache_alloc(rbd_img_request_cache, GFP_NOIO);
2149         if (!img_request)
2150                 return NULL;
2151
2152         img_request->rq = NULL;
2153         img_request->rbd_dev = rbd_dev;
2154         img_request->offset = offset;
2155         img_request->length = length;
2156         img_request->flags = 0;
2157         if (op_type == OBJ_OP_DISCARD) {
2158                 img_request_discard_set(img_request);
2159                 img_request->snapc = snapc;
2160         } else if (op_type == OBJ_OP_WRITE) {
2161                 img_request_write_set(img_request);
2162                 img_request->snapc = snapc;
2163         } else {
2164                 img_request->snap_id = rbd_dev->spec->snap_id;
2165         }
2166         if (rbd_dev_parent_get(rbd_dev))
2167                 img_request_layered_set(img_request);
2168         spin_lock_init(&img_request->completion_lock);
2169         img_request->next_completion = 0;
2170         img_request->callback = NULL;
2171         img_request->result = 0;
2172         img_request->obj_request_count = 0;
2173         INIT_LIST_HEAD(&img_request->obj_requests);
2174         kref_init(&img_request->kref);
2175
2176         dout("%s: rbd_dev %p %s %llu/%llu -> img %p\n", __func__, rbd_dev,
2177                 obj_op_name(op_type), offset, length, img_request);
2178
2179         return img_request;
2180 }
2181
2182 static void rbd_img_request_destroy(struct kref *kref)
2183 {
2184         struct rbd_img_request *img_request;
2185         struct rbd_obj_request *obj_request;
2186         struct rbd_obj_request *next_obj_request;
2187
2188         img_request = container_of(kref, struct rbd_img_request, kref);
2189
2190         dout("%s: img %p\n", __func__, img_request);
2191
2192         for_each_obj_request_safe(img_request, obj_request, next_obj_request)
2193                 rbd_img_obj_request_del(img_request, obj_request);
2194         rbd_assert(img_request->obj_request_count == 0);
2195
2196         if (img_request_layered_test(img_request)) {
2197                 img_request_layered_clear(img_request);
2198                 rbd_dev_parent_put(img_request->rbd_dev);
2199         }
2200
2201         if (img_request_write_test(img_request) ||
2202                 img_request_discard_test(img_request))
2203                 ceph_put_snap_context(img_request->snapc);
2204
2205         kmem_cache_free(rbd_img_request_cache, img_request);
2206 }
2207
2208 static struct rbd_img_request *rbd_parent_request_create(
2209                                         struct rbd_obj_request *obj_request,
2210                                         u64 img_offset, u64 length)
2211 {
2212         struct rbd_img_request *parent_request;
2213         struct rbd_device *rbd_dev;
2214
2215         rbd_assert(obj_request->img_request);
2216         rbd_dev = obj_request->img_request->rbd_dev;
2217
2218         parent_request = rbd_img_request_create(rbd_dev->parent, img_offset,
2219                                                 length, OBJ_OP_READ, NULL);
2220         if (!parent_request)
2221                 return NULL;
2222
2223         img_request_child_set(parent_request);
2224         rbd_obj_request_get(obj_request);
2225         parent_request->obj_request = obj_request;
2226
2227         return parent_request;
2228 }
2229
2230 static void rbd_parent_request_destroy(struct kref *kref)
2231 {
2232         struct rbd_img_request *parent_request;
2233         struct rbd_obj_request *orig_request;
2234
2235         parent_request = container_of(kref, struct rbd_img_request, kref);
2236         orig_request = parent_request->obj_request;
2237
2238         parent_request->obj_request = NULL;
2239         rbd_obj_request_put(orig_request);
2240         img_request_child_clear(parent_request);
2241
2242         rbd_img_request_destroy(kref);
2243 }
2244
2245 static bool rbd_img_obj_end_request(struct rbd_obj_request *obj_request)
2246 {
2247         struct rbd_img_request *img_request;
2248         unsigned int xferred;
2249         int result;
2250         bool more;
2251
2252         rbd_assert(obj_request_img_data_test(obj_request));
2253         img_request = obj_request->img_request;
2254
2255         rbd_assert(obj_request->xferred <= (u64)UINT_MAX);
2256         xferred = (unsigned int)obj_request->xferred;
2257         result = obj_request->result;
2258         if (result) {
2259                 struct rbd_device *rbd_dev = img_request->rbd_dev;
2260                 enum obj_operation_type op_type;
2261
2262                 if (img_request_discard_test(img_request))
2263                         op_type = OBJ_OP_DISCARD;
2264                 else if (img_request_write_test(img_request))
2265                         op_type = OBJ_OP_WRITE;
2266                 else
2267                         op_type = OBJ_OP_READ;
2268
2269                 rbd_warn(rbd_dev, "%s %llx at %llx (%llx)",
2270                         obj_op_name(op_type), obj_request->length,
2271                         obj_request->img_offset, obj_request->offset);
2272                 rbd_warn(rbd_dev, "  result %d xferred %x",
2273                         result, xferred);
2274                 if (!img_request->result)
2275                         img_request->result = result;
2276                 /*
2277                  * Need to end I/O on the entire obj_request worth of
2278                  * bytes in case of error.
2279                  */
2280                 xferred = obj_request->length;
2281         }
2282
2283         if (img_request_child_test(img_request)) {
2284                 rbd_assert(img_request->obj_request != NULL);
2285                 more = obj_request->which < img_request->obj_request_count - 1;
2286         } else {
2287                 rbd_assert(img_request->rq != NULL);
2288
2289                 more = blk_update_request(img_request->rq, result, xferred);
2290                 if (!more)
2291                         __blk_mq_end_request(img_request->rq, result);
2292         }
2293
2294         return more;
2295 }
2296
2297 static void rbd_img_obj_callback(struct rbd_obj_request *obj_request)
2298 {
2299         struct rbd_img_request *img_request;
2300         u32 which = obj_request->which;
2301         bool more = true;
2302
2303         rbd_assert(obj_request_img_data_test(obj_request));
2304         img_request = obj_request->img_request;
2305
2306         dout("%s: img %p obj %p\n", __func__, img_request, obj_request);
2307         rbd_assert(img_request != NULL);
2308         rbd_assert(img_request->obj_request_count > 0);
2309         rbd_assert(which != BAD_WHICH);
2310         rbd_assert(which < img_request->obj_request_count);
2311
2312         spin_lock_irq(&img_request->completion_lock);
2313         if (which != img_request->next_completion)
2314                 goto out;
2315
2316         for_each_obj_request_from(img_request, obj_request) {
2317                 rbd_assert(more);
2318                 rbd_assert(which < img_request->obj_request_count);
2319
2320                 if (!obj_request_done_test(obj_request))
2321                         break;
2322                 more = rbd_img_obj_end_request(obj_request);
2323                 which++;
2324         }
2325
2326         rbd_assert(more ^ (which == img_request->obj_request_count));
2327         img_request->next_completion = which;
2328 out:
2329         spin_unlock_irq(&img_request->completion_lock);
2330         rbd_img_request_put(img_request);
2331
2332         if (!more)
2333                 rbd_img_request_complete(img_request);
2334 }
2335
2336 /*
2337  * Add individual osd ops to the given ceph_osd_request and prepare
2338  * them for submission. num_ops is the current number of
2339  * osd operations already to the object request.
2340  */
2341 static void rbd_img_obj_request_fill(struct rbd_obj_request *obj_request,
2342                                 struct ceph_osd_request *osd_request,
2343                                 enum obj_operation_type op_type,
2344                                 unsigned int num_ops)
2345 {
2346         struct rbd_img_request *img_request = obj_request->img_request;
2347         struct rbd_device *rbd_dev = img_request->rbd_dev;
2348         u64 object_size = rbd_obj_bytes(&rbd_dev->header);
2349         u64 offset = obj_request->offset;
2350         u64 length = obj_request->length;
2351         u64 img_end;
2352         u16 opcode;
2353
2354         if (op_type == OBJ_OP_DISCARD) {
2355                 if (!offset && length == object_size &&
2356                     (!img_request_layered_test(img_request) ||
2357                      !obj_request_overlaps_parent(obj_request))) {
2358                         opcode = CEPH_OSD_OP_DELETE;
2359                 } else if ((offset + length == object_size)) {
2360                         opcode = CEPH_OSD_OP_TRUNCATE;
2361                 } else {
2362                         down_read(&rbd_dev->header_rwsem);
2363                         img_end = rbd_dev->header.image_size;
2364                         up_read(&rbd_dev->header_rwsem);
2365
2366                         if (obj_request->img_offset + length == img_end)
2367                                 opcode = CEPH_OSD_OP_TRUNCATE;
2368                         else
2369                                 opcode = CEPH_OSD_OP_ZERO;
2370                 }
2371         } else if (op_type == OBJ_OP_WRITE) {
2372                 if (!offset && length == object_size)
2373                         opcode = CEPH_OSD_OP_WRITEFULL;
2374                 else
2375                         opcode = CEPH_OSD_OP_WRITE;
2376                 osd_req_op_alloc_hint_init(osd_request, num_ops,
2377                                         object_size, object_size);
2378                 num_ops++;
2379         } else {
2380                 opcode = CEPH_OSD_OP_READ;
2381         }
2382
2383         if (opcode == CEPH_OSD_OP_DELETE)
2384                 osd_req_op_init(osd_request, num_ops, opcode, 0);
2385         else
2386                 osd_req_op_extent_init(osd_request, num_ops, opcode,
2387                                        offset, length, 0, 0);
2388
2389         if (obj_request->type == OBJ_REQUEST_BIO)
2390                 osd_req_op_extent_osd_data_bio(osd_request, num_ops,
2391                                         obj_request->bio_list, length);
2392         else if (obj_request->type == OBJ_REQUEST_PAGES)
2393                 osd_req_op_extent_osd_data_pages(osd_request, num_ops,
2394                                         obj_request->pages, length,
2395                                         offset & ~PAGE_MASK, false, false);
2396
2397         /* Discards are also writes */
2398         if (op_type == OBJ_OP_WRITE || op_type == OBJ_OP_DISCARD)
2399                 rbd_osd_req_format_write(obj_request);
2400         else
2401                 rbd_osd_req_format_read(obj_request);
2402 }
2403
2404 /*
2405  * Split up an image request into one or more object requests, each
2406  * to a different object.  The "type" parameter indicates whether
2407  * "data_desc" is the pointer to the head of a list of bio
2408  * structures, or the base of a page array.  In either case this
2409  * function assumes data_desc describes memory sufficient to hold
2410  * all data described by the image request.
2411  */
2412 static int rbd_img_request_fill(struct rbd_img_request *img_request,
2413                                         enum obj_request_type type,
2414                                         void *data_desc)
2415 {
2416         struct rbd_device *rbd_dev = img_request->rbd_dev;
2417         struct rbd_obj_request *obj_request = NULL;
2418         struct rbd_obj_request *next_obj_request;
2419         struct bio *bio_list = NULL;
2420         unsigned int bio_offset = 0;
2421         struct page **pages = NULL;
2422         enum obj_operation_type op_type;
2423         u64 img_offset;
2424         u64 resid;
2425
2426         dout("%s: img %p type %d data_desc %p\n", __func__, img_request,
2427                 (int)type, data_desc);
2428
2429         img_offset = img_request->offset;
2430         resid = img_request->length;
2431         rbd_assert(resid > 0);
2432         op_type = rbd_img_request_op_type(img_request);
2433
2434         if (type == OBJ_REQUEST_BIO) {
2435                 bio_list = data_desc;
2436                 rbd_assert(img_offset ==
2437                            bio_list->bi_iter.bi_sector << SECTOR_SHIFT);
2438         } else if (type == OBJ_REQUEST_PAGES) {
2439                 pages = data_desc;
2440         }
2441
2442         while (resid) {
2443                 struct ceph_osd_request *osd_req;
2444                 u64 object_no = img_offset >> rbd_dev->header.obj_order;
2445                 u64 offset = rbd_segment_offset(rbd_dev, img_offset);
2446                 u64 length = rbd_segment_length(rbd_dev, img_offset, resid);
2447
2448                 obj_request = rbd_obj_request_create(type);
2449                 if (!obj_request)
2450                         goto out_unwind;
2451
2452                 obj_request->object_no = object_no;
2453                 obj_request->offset = offset;
2454                 obj_request->length = length;
2455
2456                 /*
2457                  * set obj_request->img_request before creating the
2458                  * osd_request so that it gets the right snapc
2459                  */
2460                 rbd_img_obj_request_add(img_request, obj_request);
2461
2462                 if (type == OBJ_REQUEST_BIO) {
2463                         unsigned int clone_size;
2464
2465                         rbd_assert(length <= (u64)UINT_MAX);
2466                         clone_size = (unsigned int)length;
2467                         obj_request->bio_list =
2468                                         bio_chain_clone_range(&bio_list,
2469                                                                 &bio_offset,
2470                                                                 clone_size,
2471                                                                 GFP_NOIO);
2472                         if (!obj_request->bio_list)
2473                                 goto out_unwind;
2474                 } else if (type == OBJ_REQUEST_PAGES) {
2475                         unsigned int page_count;
2476
2477                         obj_request->pages = pages;
2478                         page_count = (u32)calc_pages_for(offset, length);
2479                         obj_request->page_count = page_count;
2480                         if ((offset + length) & ~PAGE_MASK)
2481                                 page_count--;   /* more on last page */
2482                         pages += page_count;
2483                 }
2484
2485                 osd_req = rbd_osd_req_create(rbd_dev, op_type,
2486                                         (op_type == OBJ_OP_WRITE) ? 2 : 1,
2487                                         obj_request);
2488                 if (!osd_req)
2489                         goto out_unwind;
2490
2491                 obj_request->osd_req = osd_req;
2492                 obj_request->callback = rbd_img_obj_callback;
2493                 obj_request->img_offset = img_offset;
2494
2495                 rbd_img_obj_request_fill(obj_request, osd_req, op_type, 0);
2496
2497                 img_offset += length;
2498                 resid -= length;
2499         }
2500
2501         return 0;
2502
2503 out_unwind:
2504         for_each_obj_request_safe(img_request, obj_request, next_obj_request)
2505                 rbd_img_obj_request_del(img_request, obj_request);
2506
2507         return -ENOMEM;
2508 }
2509
2510 static void
2511 rbd_osd_copyup_callback(struct rbd_obj_request *obj_request)
2512 {
2513         struct rbd_img_request *img_request;
2514         struct rbd_device *rbd_dev;
2515         struct page **pages;
2516         u32 page_count;
2517
2518         dout("%s: obj %p\n", __func__, obj_request);
2519
2520         rbd_assert(obj_request->type == OBJ_REQUEST_BIO ||
2521                 obj_request->type == OBJ_REQUEST_NODATA);
2522         rbd_assert(obj_request_img_data_test(obj_request));
2523         img_request = obj_request->img_request;
2524         rbd_assert(img_request);
2525
2526         rbd_dev = img_request->rbd_dev;
2527         rbd_assert(rbd_dev);
2528
2529         pages = obj_request->copyup_pages;
2530         rbd_assert(pages != NULL);
2531         obj_request->copyup_pages = NULL;
2532         page_count = obj_request->copyup_page_count;
2533         rbd_assert(page_count);
2534         obj_request->copyup_page_count = 0;
2535         ceph_release_page_vector(pages, page_count);
2536
2537         /*
2538          * We want the transfer count to reflect the size of the
2539          * original write request.  There is no such thing as a
2540          * successful short write, so if the request was successful
2541          * we can just set it to the originally-requested length.
2542          */
2543         if (!obj_request->result)
2544                 obj_request->xferred = obj_request->length;
2545
2546         obj_request_done_set(obj_request);
2547 }
2548
2549 static void
2550 rbd_img_obj_parent_read_full_callback(struct rbd_img_request *img_request)
2551 {
2552         struct rbd_obj_request *orig_request;
2553         struct ceph_osd_request *osd_req;
2554         struct rbd_device *rbd_dev;
2555         struct page **pages;
2556         enum obj_operation_type op_type;
2557         u32 page_count;
2558         int img_result;
2559         u64 parent_length;
2560
2561         rbd_assert(img_request_child_test(img_request));
2562
2563         /* First get what we need from the image request */
2564
2565         pages = img_request->copyup_pages;
2566         rbd_assert(pages != NULL);
2567         img_request->copyup_pages = NULL;
2568         page_count = img_request->copyup_page_count;
2569         rbd_assert(page_count);
2570         img_request->copyup_page_count = 0;
2571
2572         orig_request = img_request->obj_request;
2573         rbd_assert(orig_request != NULL);
2574         rbd_assert(obj_request_type_valid(orig_request->type));
2575         img_result = img_request->result;
2576         parent_length = img_request->length;
2577         rbd_assert(img_result || parent_length == img_request->xferred);
2578         rbd_img_request_put(img_request);
2579
2580         rbd_assert(orig_request->img_request);
2581         rbd_dev = orig_request->img_request->rbd_dev;
2582         rbd_assert(rbd_dev);
2583
2584         /*
2585          * If the overlap has become 0 (most likely because the
2586          * image has been flattened) we need to free the pages
2587          * and re-submit the original write request.
2588          */
2589         if (!rbd_dev->parent_overlap) {
2590                 ceph_release_page_vector(pages, page_count);
2591                 rbd_obj_request_submit(orig_request);
2592                 return;
2593         }
2594
2595         if (img_result)
2596                 goto out_err;
2597
2598         /*
2599          * The original osd request is of no use to use any more.
2600          * We need a new one that can hold the three ops in a copyup
2601          * request.  Allocate the new copyup osd request for the
2602          * original request, and release the old one.
2603          */
2604         img_result = -ENOMEM;
2605         osd_req = rbd_osd_req_create_copyup(orig_request);
2606         if (!osd_req)
2607                 goto out_err;
2608         rbd_osd_req_destroy(orig_request->osd_req);
2609         orig_request->osd_req = osd_req;
2610         orig_request->copyup_pages = pages;
2611         orig_request->copyup_page_count = page_count;
2612
2613         /* Initialize the copyup op */
2614
2615         osd_req_op_cls_init(osd_req, 0, CEPH_OSD_OP_CALL, "rbd", "copyup");
2616         osd_req_op_cls_request_data_pages(osd_req, 0, pages, parent_length, 0,
2617                                                 false, false);
2618
2619         /* Add the other op(s) */
2620
2621         op_type = rbd_img_request_op_type(orig_request->img_request);
2622         rbd_img_obj_request_fill(orig_request, osd_req, op_type, 1);
2623
2624         /* All set, send it off. */
2625
2626         rbd_obj_request_submit(orig_request);
2627         return;
2628
2629 out_err:
2630         ceph_release_page_vector(pages, page_count);
2631         rbd_obj_request_error(orig_request, img_result);
2632 }
2633
2634 /*
2635  * Read from the parent image the range of data that covers the
2636  * entire target of the given object request.  This is used for
2637  * satisfying a layered image write request when the target of an
2638  * object request from the image request does not exist.
2639  *
2640  * A page array big enough to hold the returned data is allocated
2641  * and supplied to rbd_img_request_fill() as the "data descriptor."
2642  * When the read completes, this page array will be transferred to
2643  * the original object request for the copyup operation.
2644  *
2645  * If an error occurs, it is recorded as the result of the original
2646  * object request in rbd_img_obj_exists_callback().
2647  */
2648 static int rbd_img_obj_parent_read_full(struct rbd_obj_request *obj_request)
2649 {
2650         struct rbd_device *rbd_dev = obj_request->img_request->rbd_dev;
2651         struct rbd_img_request *parent_request = NULL;
2652         u64 img_offset;
2653         u64 length;
2654         struct page **pages = NULL;
2655         u32 page_count;
2656         int result;
2657
2658         rbd_assert(rbd_dev->parent != NULL);
2659
2660         /*
2661          * Determine the byte range covered by the object in the
2662          * child image to which the original request was to be sent.
2663          */
2664         img_offset = obj_request->img_offset - obj_request->offset;
2665         length = rbd_obj_bytes(&rbd_dev->header);
2666
2667         /*
2668          * There is no defined parent data beyond the parent
2669          * overlap, so limit what we read at that boundary if
2670          * necessary.
2671          */
2672         if (img_offset + length > rbd_dev->parent_overlap) {
2673                 rbd_assert(img_offset < rbd_dev->parent_overlap);
2674                 length = rbd_dev->parent_overlap - img_offset;
2675         }
2676
2677         /*
2678          * Allocate a page array big enough to receive the data read
2679          * from the parent.
2680          */
2681         page_count = (u32)calc_pages_for(0, length);
2682         pages = ceph_alloc_page_vector(page_count, GFP_KERNEL);
2683         if (IS_ERR(pages)) {
2684                 result = PTR_ERR(pages);
2685                 pages = NULL;
2686                 goto out_err;
2687         }
2688
2689         result = -ENOMEM;
2690         parent_request = rbd_parent_request_create(obj_request,
2691                                                 img_offset, length);
2692         if (!parent_request)
2693                 goto out_err;
2694
2695         result = rbd_img_request_fill(parent_request, OBJ_REQUEST_PAGES, pages);
2696         if (result)
2697                 goto out_err;
2698
2699         parent_request->copyup_pages = pages;
2700         parent_request->copyup_page_count = page_count;
2701         parent_request->callback = rbd_img_obj_parent_read_full_callback;
2702
2703         result = rbd_img_request_submit(parent_request);
2704         if (!result)
2705                 return 0;
2706
2707         parent_request->copyup_pages = NULL;
2708         parent_request->copyup_page_count = 0;
2709         parent_request->obj_request = NULL;
2710         rbd_obj_request_put(obj_request);
2711 out_err:
2712         if (pages)
2713                 ceph_release_page_vector(pages, page_count);
2714         if (parent_request)
2715                 rbd_img_request_put(parent_request);
2716         return result;
2717 }
2718
2719 static void rbd_img_obj_exists_callback(struct rbd_obj_request *obj_request)
2720 {
2721         struct rbd_obj_request *orig_request;
2722         struct rbd_device *rbd_dev;
2723         int result;
2724
2725         rbd_assert(!obj_request_img_data_test(obj_request));
2726
2727         /*
2728          * All we need from the object request is the original
2729          * request and the result of the STAT op.  Grab those, then
2730          * we're done with the request.
2731          */
2732         orig_request = obj_request->obj_request;
2733         obj_request->obj_request = NULL;
2734         rbd_obj_request_put(orig_request);
2735         rbd_assert(orig_request);
2736         rbd_assert(orig_request->img_request);
2737
2738         result = obj_request->result;
2739         obj_request->result = 0;
2740
2741         dout("%s: obj %p for obj %p result %d %llu/%llu\n", __func__,
2742                 obj_request, orig_request, result,
2743                 obj_request->xferred, obj_request->length);
2744         rbd_obj_request_put(obj_request);
2745
2746         /*
2747          * If the overlap has become 0 (most likely because the
2748          * image has been flattened) we need to re-submit the
2749          * original request.
2750          */
2751         rbd_dev = orig_request->img_request->rbd_dev;
2752         if (!rbd_dev->parent_overlap) {
2753                 rbd_obj_request_submit(orig_request);
2754                 return;
2755         }
2756
2757         /*
2758          * Our only purpose here is to determine whether the object
2759          * exists, and we don't want to treat the non-existence as
2760          * an error.  If something else comes back, transfer the
2761          * error to the original request and complete it now.
2762          */
2763         if (!result) {
2764                 obj_request_existence_set(orig_request, true);
2765         } else if (result == -ENOENT) {
2766                 obj_request_existence_set(orig_request, false);
2767         } else {
2768                 goto fail_orig_request;
2769         }
2770
2771         /*
2772          * Resubmit the original request now that we have recorded
2773          * whether the target object exists.
2774          */
2775         result = rbd_img_obj_request_submit(orig_request);
2776         if (result)
2777                 goto fail_orig_request;
2778
2779         return;
2780
2781 fail_orig_request:
2782         rbd_obj_request_error(orig_request, result);
2783 }
2784
2785 static int rbd_img_obj_exists_submit(struct rbd_obj_request *obj_request)
2786 {
2787         struct rbd_device *rbd_dev = obj_request->img_request->rbd_dev;
2788         struct rbd_obj_request *stat_request;
2789         struct page **pages;
2790         u32 page_count;
2791         size_t size;
2792         int ret;
2793
2794         stat_request = rbd_obj_request_create(OBJ_REQUEST_PAGES);
2795         if (!stat_request)
2796                 return -ENOMEM;
2797
2798         stat_request->object_no = obj_request->object_no;
2799
2800         stat_request->osd_req = rbd_osd_req_create(rbd_dev, OBJ_OP_READ, 1,
2801                                                    stat_request);
2802         if (!stat_request->osd_req) {
2803                 ret = -ENOMEM;
2804                 goto fail_stat_request;
2805         }
2806
2807         /*
2808          * The response data for a STAT call consists of:
2809          *     le64 length;
2810          *     struct {
2811          *         le32 tv_sec;
2812          *         le32 tv_nsec;
2813          *     } mtime;
2814          */
2815         size = sizeof (__le64) + sizeof (__le32) + sizeof (__le32);
2816         page_count = (u32)calc_pages_for(0, size);
2817         pages = ceph_alloc_page_vector(page_count, GFP_KERNEL);
2818         if (IS_ERR(pages)) {
2819                 ret = PTR_ERR(pages);
2820                 goto fail_stat_request;
2821         }
2822
2823         osd_req_op_init(stat_request->osd_req, 0, CEPH_OSD_OP_STAT, 0);
2824         osd_req_op_raw_data_in_pages(stat_request->osd_req, 0, pages, size, 0,
2825                                      false, false);
2826
2827         rbd_obj_request_get(obj_request);
2828         stat_request->obj_request = obj_request;
2829         stat_request->pages = pages;
2830         stat_request->page_count = page_count;
2831         stat_request->callback = rbd_img_obj_exists_callback;
2832
2833         rbd_obj_request_submit(stat_request);
2834         return 0;
2835
2836 fail_stat_request:
2837         rbd_obj_request_put(stat_request);
2838         return ret;
2839 }
2840
2841 static bool img_obj_request_simple(struct rbd_obj_request *obj_request)
2842 {
2843         struct rbd_img_request *img_request = obj_request->img_request;
2844         struct rbd_device *rbd_dev = img_request->rbd_dev;
2845
2846         /* Reads */
2847         if (!img_request_write_test(img_request) &&
2848             !img_request_discard_test(img_request))
2849                 return true;
2850
2851         /* Non-layered writes */
2852         if (!img_request_layered_test(img_request))
2853                 return true;
2854
2855         /*
2856          * Layered writes outside of the parent overlap range don't
2857          * share any data with the parent.
2858          */
2859         if (!obj_request_overlaps_parent(obj_request))
2860                 return true;
2861
2862         /*
2863          * Entire-object layered writes - we will overwrite whatever
2864          * parent data there is anyway.
2865          */
2866         if (!obj_request->offset &&
2867             obj_request->length == rbd_obj_bytes(&rbd_dev->header))
2868                 return true;
2869
2870         /*
2871          * If the object is known to already exist, its parent data has
2872          * already been copied.
2873          */
2874         if (obj_request_known_test(obj_request) &&
2875             obj_request_exists_test(obj_request))
2876                 return true;
2877
2878         return false;
2879 }
2880
2881 static int rbd_img_obj_request_submit(struct rbd_obj_request *obj_request)
2882 {
2883         rbd_assert(obj_request_img_data_test(obj_request));
2884         rbd_assert(obj_request_type_valid(obj_request->type));
2885         rbd_assert(obj_request->img_request);
2886
2887         if (img_obj_request_simple(obj_request)) {
2888                 rbd_obj_request_submit(obj_request);
2889                 return 0;
2890         }
2891
2892         /*
2893          * It's a layered write.  The target object might exist but
2894          * we may not know that yet.  If we know it doesn't exist,
2895          * start by reading the data for the full target object from
2896          * the parent so we can use it for a copyup to the target.
2897          */
2898         if (obj_request_known_test(obj_request))
2899                 return rbd_img_obj_parent_read_full(obj_request);
2900
2901         /* We don't know whether the target exists.  Go find out. */
2902
2903         return rbd_img_obj_exists_submit(obj_request);
2904 }
2905
2906 static int rbd_img_request_submit(struct rbd_img_request *img_request)
2907 {
2908         struct rbd_obj_request *obj_request;
2909         struct rbd_obj_request *next_obj_request;
2910         int ret = 0;
2911
2912         dout("%s: img %p\n", __func__, img_request);
2913
2914         rbd_img_request_get(img_request);
2915         for_each_obj_request_safe(img_request, obj_request, next_obj_request) {
2916                 ret = rbd_img_obj_request_submit(obj_request);
2917                 if (ret)
2918                         goto out_put_ireq;
2919         }
2920
2921 out_put_ireq:
2922         rbd_img_request_put(img_request);
2923         return ret;
2924 }
2925
2926 static void rbd_img_parent_read_callback(struct rbd_img_request *img_request)
2927 {
2928         struct rbd_obj_request *obj_request;
2929         struct rbd_device *rbd_dev;
2930         u64 obj_end;
2931         u64 img_xferred;
2932         int img_result;
2933
2934         rbd_assert(img_request_child_test(img_request));
2935
2936         /* First get what we need from the image request and release it */
2937
2938         obj_request = img_request->obj_request;
2939         img_xferred = img_request->xferred;
2940         img_result = img_request->result;
2941         rbd_img_request_put(img_request);
2942
2943         /*
2944          * If the overlap has become 0 (most likely because the
2945          * image has been flattened) we need to re-submit the
2946          * original request.
2947          */
2948         rbd_assert(obj_request);
2949         rbd_assert(obj_request->img_request);
2950         rbd_dev = obj_request->img_request->rbd_dev;
2951         if (!rbd_dev->parent_overlap) {
2952                 rbd_obj_request_submit(obj_request);
2953                 return;
2954         }
2955
2956         obj_request->result = img_result;
2957         if (obj_request->result)
2958                 goto out;
2959
2960         /*
2961          * We need to zero anything beyond the parent overlap
2962          * boundary.  Since rbd_img_obj_request_read_callback()
2963          * will zero anything beyond the end of a short read, an
2964          * easy way to do this is to pretend the data from the
2965          * parent came up short--ending at the overlap boundary.
2966          */
2967         rbd_assert(obj_request->img_offset < U64_MAX - obj_request->length);
2968         obj_end = obj_request->img_offset + obj_request->length;
2969         if (obj_end > rbd_dev->parent_overlap) {
2970                 u64 xferred = 0;
2971
2972                 if (obj_request->img_offset < rbd_dev->parent_overlap)
2973                         xferred = rbd_dev->parent_overlap -
2974                                         obj_request->img_offset;
2975
2976                 obj_request->xferred = min(img_xferred, xferred);
2977         } else {
2978                 obj_request->xferred = img_xferred;
2979         }
2980 out:
2981         rbd_img_obj_request_read_callback(obj_request);
2982         rbd_obj_request_complete(obj_request);
2983 }
2984
2985 static void rbd_img_parent_read(struct rbd_obj_request *obj_request)
2986 {
2987         struct rbd_img_request *img_request;
2988         int result;
2989
2990         rbd_assert(obj_request_img_data_test(obj_request));
2991         rbd_assert(obj_request->img_request != NULL);
2992         rbd_assert(obj_request->result == (s32) -ENOENT);
2993         rbd_assert(obj_request_type_valid(obj_request->type));
2994
2995         /* rbd_read_finish(obj_request, obj_request->length); */
2996         img_request = rbd_parent_request_create(obj_request,
2997                                                 obj_request->img_offset,
2998                                                 obj_request->length);
2999         result = -ENOMEM;
3000         if (!img_request)
3001                 goto out_err;
3002
3003         if (obj_request->type == OBJ_REQUEST_BIO)
3004                 result = rbd_img_request_fill(img_request, OBJ_REQUEST_BIO,
3005                                                 obj_request->bio_list);
3006         else
3007                 result = rbd_img_request_fill(img_request, OBJ_REQUEST_PAGES,
3008                                                 obj_request->pages);
3009         if (result)
3010                 goto out_err;
3011
3012         img_request->callback = rbd_img_parent_read_callback;
3013         result = rbd_img_request_submit(img_request);
3014         if (result)
3015                 goto out_err;
3016
3017         return;
3018 out_err:
3019         if (img_request)
3020                 rbd_img_request_put(img_request);
3021         obj_request->result = result;
3022         obj_request->xferred = 0;
3023         obj_request_done_set(obj_request);
3024 }
3025
3026 static const struct rbd_client_id rbd_empty_cid;
3027
3028 static bool rbd_cid_equal(const struct rbd_client_id *lhs,
3029                           const struct rbd_client_id *rhs)
3030 {
3031         return lhs->gid == rhs->gid && lhs->handle == rhs->handle;
3032 }
3033
3034 static struct rbd_client_id rbd_get_cid(struct rbd_device *rbd_dev)
3035 {
3036         struct rbd_client_id cid;
3037
3038         mutex_lock(&rbd_dev->watch_mutex);
3039         cid.gid = ceph_client_gid(rbd_dev->rbd_client->client);
3040         cid.handle = rbd_dev->watch_cookie;
3041         mutex_unlock(&rbd_dev->watch_mutex);
3042         return cid;
3043 }
3044
3045 /*
3046  * lock_rwsem must be held for write
3047  */
3048 static void rbd_set_owner_cid(struct rbd_device *rbd_dev,
3049                               const struct rbd_client_id *cid)
3050 {
3051         dout("%s rbd_dev %p %llu-%llu -> %llu-%llu\n", __func__, rbd_dev,
3052              rbd_dev->owner_cid.gid, rbd_dev->owner_cid.handle,
3053              cid->gid, cid->handle);
3054         rbd_dev->owner_cid = *cid; /* struct */
3055 }
3056
3057 static void format_lock_cookie(struct rbd_device *rbd_dev, char *buf)
3058 {
3059         mutex_lock(&rbd_dev->watch_mutex);
3060         sprintf(buf, "%s %llu", RBD_LOCK_COOKIE_PREFIX, rbd_dev->watch_cookie);
3061         mutex_unlock(&rbd_dev->watch_mutex);
3062 }
3063
3064 /*
3065  * lock_rwsem must be held for write
3066  */
3067 static int rbd_lock(struct rbd_device *rbd_dev)
3068 {
3069         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
3070         struct rbd_client_id cid = rbd_get_cid(rbd_dev);
3071         char cookie[32];
3072         int ret;
3073
3074         WARN_ON(__rbd_is_lock_owner(rbd_dev));
3075
3076         format_lock_cookie(rbd_dev, cookie);
3077         ret = ceph_cls_lock(osdc, &rbd_dev->header_oid, &rbd_dev->header_oloc,
3078                             RBD_LOCK_NAME, CEPH_CLS_LOCK_EXCLUSIVE, cookie,
3079                             RBD_LOCK_TAG, "", 0);
3080         if (ret)
3081                 return ret;
3082
3083         rbd_dev->lock_state = RBD_LOCK_STATE_LOCKED;
3084         rbd_set_owner_cid(rbd_dev, &cid);
3085         queue_work(rbd_dev->task_wq, &rbd_dev->acquired_lock_work);
3086         return 0;
3087 }
3088
3089 /*
3090  * lock_rwsem must be held for write
3091  */
3092 static int rbd_unlock(struct rbd_device *rbd_dev)
3093 {
3094         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
3095         char cookie[32];
3096         int ret;
3097
3098         WARN_ON(!__rbd_is_lock_owner(rbd_dev));
3099
3100         rbd_dev->lock_state = RBD_LOCK_STATE_UNLOCKED;
3101
3102         format_lock_cookie(rbd_dev, cookie);
3103         ret = ceph_cls_unlock(osdc, &rbd_dev->header_oid, &rbd_dev->header_oloc,
3104                               RBD_LOCK_NAME, cookie);
3105         if (ret && ret != -ENOENT) {
3106                 rbd_warn(rbd_dev, "cls_unlock failed: %d", ret);
3107                 return ret;
3108         }
3109
3110         rbd_set_owner_cid(rbd_dev, &rbd_empty_cid);
3111         queue_work(rbd_dev->task_wq, &rbd_dev->released_lock_work);
3112         return 0;
3113 }
3114
3115 static int __rbd_notify_op_lock(struct rbd_device *rbd_dev,
3116                                 enum rbd_notify_op notify_op,
3117                                 struct page ***preply_pages,
3118                                 size_t *preply_len)
3119 {
3120         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
3121         struct rbd_client_id cid = rbd_get_cid(rbd_dev);
3122         int buf_size = 4 + 8 + 8 + CEPH_ENCODING_START_BLK_LEN;
3123         char buf[buf_size];
3124         void *p = buf;
3125
3126         dout("%s rbd_dev %p notify_op %d\n", __func__, rbd_dev, notify_op);
3127
3128         /* encode *LockPayload NotifyMessage (op + ClientId) */
3129         ceph_start_encoding(&p, 2, 1, buf_size - CEPH_ENCODING_START_BLK_LEN);
3130         ceph_encode_32(&p, notify_op);
3131         ceph_encode_64(&p, cid.gid);
3132         ceph_encode_64(&p, cid.handle);
3133
3134         return ceph_osdc_notify(osdc, &rbd_dev->header_oid,
3135                                 &rbd_dev->header_oloc, buf, buf_size,
3136                                 RBD_NOTIFY_TIMEOUT, preply_pages, preply_len);
3137 }
3138
3139 static void rbd_notify_op_lock(struct rbd_device *rbd_dev,
3140                                enum rbd_notify_op notify_op)
3141 {
3142         struct page **reply_pages;
3143         size_t reply_len;
3144
3145         __rbd_notify_op_lock(rbd_dev, notify_op, &reply_pages, &reply_len);
3146         ceph_release_page_vector(reply_pages, calc_pages_for(0, reply_len));
3147 }
3148
3149 static void rbd_notify_acquired_lock(struct work_struct *work)
3150 {
3151         struct rbd_device *rbd_dev = container_of(work, struct rbd_device,
3152                                                   acquired_lock_work);
3153
3154         rbd_notify_op_lock(rbd_dev, RBD_NOTIFY_OP_ACQUIRED_LOCK);
3155 }
3156
3157 static void rbd_notify_released_lock(struct work_struct *work)
3158 {
3159         struct rbd_device *rbd_dev = container_of(work, struct rbd_device,
3160                                                   released_lock_work);
3161
3162         rbd_notify_op_lock(rbd_dev, RBD_NOTIFY_OP_RELEASED_LOCK);
3163 }
3164
3165 static int rbd_request_lock(struct rbd_device *rbd_dev)
3166 {
3167         struct page **reply_pages;
3168         size_t reply_len;
3169         bool lock_owner_responded = false;
3170         int ret;
3171
3172         dout("%s rbd_dev %p\n", __func__, rbd_dev);
3173
3174         ret = __rbd_notify_op_lock(rbd_dev, RBD_NOTIFY_OP_REQUEST_LOCK,
3175                                    &reply_pages, &reply_len);
3176         if (ret && ret != -ETIMEDOUT) {
3177                 rbd_warn(rbd_dev, "failed to request lock: %d", ret);
3178                 goto out;
3179         }
3180
3181         if (reply_len > 0 && reply_len <= PAGE_SIZE) {
3182                 void *p = page_address(reply_pages[0]);
3183                 void *const end = p + reply_len;
3184                 u32 n;
3185
3186                 ceph_decode_32_safe(&p, end, n, e_inval); /* num_acks */
3187                 while (n--) {
3188                         u8 struct_v;
3189                         u32 len;
3190
3191                         ceph_decode_need(&p, end, 8 + 8, e_inval);
3192                         p += 8 + 8; /* skip gid and cookie */
3193
3194                         ceph_decode_32_safe(&p, end, len, e_inval);
3195                         if (!len)
3196                                 continue;
3197
3198                         if (lock_owner_responded) {
3199                                 rbd_warn(rbd_dev,
3200                                          "duplicate lock owners detected");
3201                                 ret = -EIO;
3202                                 goto out;
3203                         }
3204
3205                         lock_owner_responded = true;
3206                         ret = ceph_start_decoding(&p, end, 1, "ResponseMessage",
3207                                                   &struct_v, &len);
3208                         if (ret) {
3209                                 rbd_warn(rbd_dev,
3210                                          "failed to decode ResponseMessage: %d",
3211                                          ret);
3212                                 goto e_inval;
3213                         }
3214
3215                         ret = ceph_decode_32(&p);
3216                 }
3217         }
3218
3219         if (!lock_owner_responded) {
3220                 rbd_warn(rbd_dev, "no lock owners detected");
3221                 ret = -ETIMEDOUT;
3222         }
3223
3224 out:
3225         ceph_release_page_vector(reply_pages, calc_pages_for(0, reply_len));
3226         return ret;
3227
3228 e_inval:
3229         ret = -EINVAL;
3230         goto out;
3231 }
3232
3233 static void wake_requests(struct rbd_device *rbd_dev, bool wake_all)
3234 {
3235         dout("%s rbd_dev %p wake_all %d\n", __func__, rbd_dev, wake_all);
3236
3237         cancel_delayed_work(&rbd_dev->lock_dwork);
3238         if (wake_all)
3239                 wake_up_all(&rbd_dev->lock_waitq);
3240         else
3241                 wake_up(&rbd_dev->lock_waitq);
3242 }
3243
3244 static int get_lock_owner_info(struct rbd_device *rbd_dev,
3245                                struct ceph_locker **lockers, u32 *num_lockers)
3246 {
3247         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
3248         u8 lock_type;
3249         char *lock_tag;
3250         int ret;
3251
3252         dout("%s rbd_dev %p\n", __func__, rbd_dev);
3253
3254         ret = ceph_cls_lock_info(osdc, &rbd_dev->header_oid,
3255                                  &rbd_dev->header_oloc, RBD_LOCK_NAME,
3256                                  &lock_type, &lock_tag, lockers, num_lockers);
3257         if (ret)
3258                 return ret;
3259
3260         if (*num_lockers == 0) {
3261                 dout("%s rbd_dev %p no lockers detected\n", __func__, rbd_dev);
3262                 goto out;
3263         }
3264
3265         if (strcmp(lock_tag, RBD_LOCK_TAG)) {
3266                 rbd_warn(rbd_dev, "locked by external mechanism, tag %s",
3267                          lock_tag);
3268                 ret = -EBUSY;
3269                 goto out;
3270         }
3271
3272         if (lock_type == CEPH_CLS_LOCK_SHARED) {
3273                 rbd_warn(rbd_dev, "shared lock type detected");
3274                 ret = -EBUSY;
3275                 goto out;
3276         }
3277
3278         if (strncmp((*lockers)[0].id.cookie, RBD_LOCK_COOKIE_PREFIX,
3279                     strlen(RBD_LOCK_COOKIE_PREFIX))) {
3280                 rbd_warn(rbd_dev, "locked by external mechanism, cookie %s",
3281                          (*lockers)[0].id.cookie);
3282                 ret = -EBUSY;
3283                 goto out;
3284         }
3285
3286 out:
3287         kfree(lock_tag);
3288         return ret;
3289 }
3290
3291 static int find_watcher(struct rbd_device *rbd_dev,
3292                         const struct ceph_locker *locker)
3293 {
3294         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
3295         struct ceph_watch_item *watchers;
3296         u32 num_watchers;
3297         u64 cookie;
3298         int i;
3299         int ret;
3300
3301         ret = ceph_osdc_list_watchers(osdc, &rbd_dev->header_oid,
3302                                       &rbd_dev->header_oloc, &watchers,
3303                                       &num_watchers);
3304         if (ret)
3305                 return ret;
3306
3307         sscanf(locker->id.cookie, RBD_LOCK_COOKIE_PREFIX " %llu", &cookie);
3308         for (i = 0; i < num_watchers; i++) {
3309                 if (!memcmp(&watchers[i].addr, &locker->info.addr,
3310                             sizeof(locker->info.addr)) &&
3311                     watchers[i].cookie == cookie) {
3312                         struct rbd_client_id cid = {
3313                                 .gid = le64_to_cpu(watchers[i].name.num),
3314                                 .handle = cookie,
3315                         };
3316
3317                         dout("%s rbd_dev %p found cid %llu-%llu\n", __func__,
3318                              rbd_dev, cid.gid, cid.handle);
3319                         rbd_set_owner_cid(rbd_dev, &cid);
3320                         ret = 1;
3321                         goto out;
3322                 }
3323         }
3324
3325         dout("%s rbd_dev %p no watchers\n", __func__, rbd_dev);
3326         ret = 0;
3327 out:
3328         kfree(watchers);
3329         return ret;
3330 }
3331
3332 /*
3333  * lock_rwsem must be held for write
3334  */
3335 static int rbd_try_lock(struct rbd_device *rbd_dev)
3336 {
3337         struct ceph_client *client = rbd_dev->rbd_client->client;
3338         struct ceph_locker *lockers;
3339         u32 num_lockers;
3340         int ret;
3341
3342         for (;;) {
3343                 ret = rbd_lock(rbd_dev);
3344                 if (ret != -EBUSY)
3345                         return ret;
3346
3347                 /* determine if the current lock holder is still alive */
3348                 ret = get_lock_owner_info(rbd_dev, &lockers, &num_lockers);
3349                 if (ret)
3350                         return ret;
3351
3352                 if (num_lockers == 0)
3353                         goto again;
3354
3355                 ret = find_watcher(rbd_dev, lockers);
3356                 if (ret) {
3357                         if (ret > 0)
3358                                 ret = 0; /* have to request lock */
3359                         goto out;
3360                 }
3361
3362                 rbd_warn(rbd_dev, "%s%llu seems dead, breaking lock",
3363                          ENTITY_NAME(lockers[0].id.name));
3364
3365                 ret = ceph_monc_blacklist_add(&client->monc,
3366                                               &lockers[0].info.addr);
3367                 if (ret) {
3368                         rbd_warn(rbd_dev, "blacklist of %s%llu failed: %d",
3369                                  ENTITY_NAME(lockers[0].id.name), ret);
3370                         goto out;
3371                 }
3372
3373                 ret = ceph_cls_break_lock(&client->osdc, &rbd_dev->header_oid,
3374                                           &rbd_dev->header_oloc, RBD_LOCK_NAME,
3375                                           lockers[0].id.cookie,
3376                                           &lockers[0].id.name);
3377                 if (ret && ret != -ENOENT)
3378                         goto out;
3379
3380 again:
3381                 ceph_free_lockers(lockers, num_lockers);
3382         }
3383
3384 out:
3385         ceph_free_lockers(lockers, num_lockers);
3386         return ret;
3387 }
3388
3389 /*
3390  * ret is set only if lock_state is RBD_LOCK_STATE_UNLOCKED
3391  */
3392 static enum rbd_lock_state rbd_try_acquire_lock(struct rbd_device *rbd_dev,
3393                                                 int *pret)
3394 {
3395         enum rbd_lock_state lock_state;
3396
3397         down_read(&rbd_dev->lock_rwsem);
3398         dout("%s rbd_dev %p read lock_state %d\n", __func__, rbd_dev,
3399              rbd_dev->lock_state);
3400         if (__rbd_is_lock_owner(rbd_dev)) {
3401                 lock_state = rbd_dev->lock_state;
3402                 up_read(&rbd_dev->lock_rwsem);
3403                 return lock_state;
3404         }
3405
3406         up_read(&rbd_dev->lock_rwsem);
3407         down_write(&rbd_dev->lock_rwsem);
3408         dout("%s rbd_dev %p write lock_state %d\n", __func__, rbd_dev,
3409              rbd_dev->lock_state);
3410         if (!__rbd_is_lock_owner(rbd_dev)) {
3411                 *pret = rbd_try_lock(rbd_dev);
3412                 if (*pret)
3413                         rbd_warn(rbd_dev, "failed to acquire lock: %d", *pret);
3414         }
3415
3416         lock_state = rbd_dev->lock_state;
3417         up_write(&rbd_dev->lock_rwsem);
3418         return lock_state;
3419 }
3420
3421 static void rbd_acquire_lock(struct work_struct *work)
3422 {
3423         struct rbd_device *rbd_dev = container_of(to_delayed_work(work),
3424                                             struct rbd_device, lock_dwork);
3425         enum rbd_lock_state lock_state;
3426         int ret;
3427
3428         dout("%s rbd_dev %p\n", __func__, rbd_dev);
3429 again:
3430         lock_state = rbd_try_acquire_lock(rbd_dev, &ret);
3431         if (lock_state != RBD_LOCK_STATE_UNLOCKED || ret == -EBLACKLISTED) {
3432                 if (lock_state == RBD_LOCK_STATE_LOCKED)
3433                         wake_requests(rbd_dev, true);
3434                 dout("%s rbd_dev %p lock_state %d ret %d - done\n", __func__,
3435                      rbd_dev, lock_state, ret);
3436                 return;
3437         }
3438
3439         ret = rbd_request_lock(rbd_dev);
3440         if (ret == -ETIMEDOUT) {
3441                 goto again; /* treat this as a dead client */
3442         } else if (ret < 0) {
3443                 rbd_warn(rbd_dev, "error requesting lock: %d", ret);
3444                 mod_delayed_work(rbd_dev->task_wq, &rbd_dev->lock_dwork,
3445                                  RBD_RETRY_DELAY);
3446         } else {
3447                 /*
3448                  * lock owner acked, but resend if we don't see them
3449                  * release the lock
3450                  */
3451                 dout("%s rbd_dev %p requeueing lock_dwork\n", __func__,
3452                      rbd_dev);
3453                 mod_delayed_work(rbd_dev->task_wq, &rbd_dev->lock_dwork,
3454                     msecs_to_jiffies(2 * RBD_NOTIFY_TIMEOUT * MSEC_PER_SEC));
3455         }
3456 }
3457
3458 /*
3459  * lock_rwsem must be held for write
3460  */
3461 static bool rbd_release_lock(struct rbd_device *rbd_dev)
3462 {
3463         dout("%s rbd_dev %p read lock_state %d\n", __func__, rbd_dev,
3464              rbd_dev->lock_state);
3465         if (rbd_dev->lock_state != RBD_LOCK_STATE_LOCKED)
3466                 return false;
3467
3468         rbd_dev->lock_state = RBD_LOCK_STATE_RELEASING;
3469         downgrade_write(&rbd_dev->lock_rwsem);
3470         /*
3471          * Ensure that all in-flight IO is flushed.
3472          *
3473          * FIXME: ceph_osdc_sync() flushes the entire OSD client, which
3474          * may be shared with other devices.
3475          */
3476         ceph_osdc_sync(&rbd_dev->rbd_client->client->osdc);
3477         up_read(&rbd_dev->lock_rwsem);
3478
3479         down_write(&rbd_dev->lock_rwsem);
3480         dout("%s rbd_dev %p write lock_state %d\n", __func__, rbd_dev,
3481              rbd_dev->lock_state);
3482         if (rbd_dev->lock_state != RBD_LOCK_STATE_RELEASING)
3483                 return false;
3484
3485         if (!rbd_unlock(rbd_dev))
3486                 /*
3487                  * Give others a chance to grab the lock - we would re-acquire
3488                  * almost immediately if we got new IO during ceph_osdc_sync()
3489                  * otherwise.  We need to ack our own notifications, so this
3490                  * lock_dwork will be requeued from rbd_wait_state_locked()
3491                  * after wake_requests() in rbd_handle_released_lock().
3492                  */
3493                 cancel_delayed_work(&rbd_dev->lock_dwork);
3494
3495         return true;
3496 }
3497
3498 static void rbd_release_lock_work(struct work_struct *work)
3499 {
3500         struct rbd_device *rbd_dev = container_of(work, struct rbd_device,
3501                                                   unlock_work);
3502
3503         down_write(&rbd_dev->lock_rwsem);
3504         rbd_release_lock(rbd_dev);
3505         up_write(&rbd_dev->lock_rwsem);
3506 }
3507
3508 static void rbd_handle_acquired_lock(struct rbd_device *rbd_dev, u8 struct_v,
3509                                      void **p)
3510 {
3511         struct rbd_client_id cid = { 0 };
3512
3513         if (struct_v >= 2) {
3514                 cid.gid = ceph_decode_64(p);
3515                 cid.handle = ceph_decode_64(p);
3516         }
3517
3518         dout("%s rbd_dev %p cid %llu-%llu\n", __func__, rbd_dev, cid.gid,
3519              cid.handle);
3520         if (!rbd_cid_equal(&cid, &rbd_empty_cid)) {
3521                 down_write(&rbd_dev->lock_rwsem);
3522                 if (rbd_cid_equal(&cid, &rbd_dev->owner_cid)) {
3523                         /*
3524                          * we already know that the remote client is
3525                          * the owner
3526                          */
3527                         up_write(&rbd_dev->lock_rwsem);
3528                         return;
3529                 }
3530
3531                 rbd_set_owner_cid(rbd_dev, &cid);
3532                 downgrade_write(&rbd_dev->lock_rwsem);
3533         } else {
3534                 down_read(&rbd_dev->lock_rwsem);
3535         }
3536
3537         if (!__rbd_is_lock_owner(rbd_dev))
3538                 wake_requests(rbd_dev, false);
3539         up_read(&rbd_dev->lock_rwsem);
3540 }
3541
3542 static void rbd_handle_released_lock(struct rbd_device *rbd_dev, u8 struct_v,
3543                                      void **p)
3544 {
3545         struct rbd_client_id cid = { 0 };
3546
3547         if (struct_v >= 2) {
3548                 cid.gid = ceph_decode_64(p);
3549                 cid.handle = ceph_decode_64(p);
3550         }
3551
3552         dout("%s rbd_dev %p cid %llu-%llu\n", __func__, rbd_dev, cid.gid,
3553              cid.handle);
3554         if (!rbd_cid_equal(&cid, &rbd_empty_cid)) {
3555                 down_write(&rbd_dev->lock_rwsem);
3556                 if (!rbd_cid_equal(&cid, &rbd_dev->owner_cid)) {
3557                         dout("%s rbd_dev %p unexpected owner, cid %llu-%llu != owner_cid %llu-%llu\n",
3558                              __func__, rbd_dev, cid.gid, cid.handle,
3559                              rbd_dev->owner_cid.gid, rbd_dev->owner_cid.handle);
3560                         up_write(&rbd_dev->lock_rwsem);
3561                         return;
3562                 }
3563
3564                 rbd_set_owner_cid(rbd_dev, &rbd_empty_cid);
3565                 downgrade_write(&rbd_dev->lock_rwsem);
3566         } else {
3567                 down_read(&rbd_dev->lock_rwsem);
3568         }
3569
3570         if (!__rbd_is_lock_owner(rbd_dev))
3571                 wake_requests(rbd_dev, false);
3572         up_read(&rbd_dev->lock_rwsem);
3573 }
3574
3575 static bool rbd_handle_request_lock(struct rbd_device *rbd_dev, u8 struct_v,
3576                                     void **p)
3577 {
3578         struct rbd_client_id my_cid = rbd_get_cid(rbd_dev);
3579         struct rbd_client_id cid = { 0 };
3580         bool need_to_send;
3581
3582         if (struct_v >= 2) {
3583                 cid.gid = ceph_decode_64(p);
3584                 cid.handle = ceph_decode_64(p);
3585         }
3586
3587         dout("%s rbd_dev %p cid %llu-%llu\n", __func__, rbd_dev, cid.gid,
3588              cid.handle);
3589         if (rbd_cid_equal(&cid, &my_cid))
3590                 return false;
3591
3592         down_read(&rbd_dev->lock_rwsem);
3593         need_to_send = __rbd_is_lock_owner(rbd_dev);
3594         if (rbd_dev->lock_state == RBD_LOCK_STATE_LOCKED) {
3595                 if (!rbd_cid_equal(&rbd_dev->owner_cid, &rbd_empty_cid)) {
3596                         dout("%s rbd_dev %p queueing unlock_work\n", __func__,
3597                              rbd_dev);
3598                         queue_work(rbd_dev->task_wq, &rbd_dev->unlock_work);
3599                 }
3600         }
3601         up_read(&rbd_dev->lock_rwsem);
3602         return need_to_send;
3603 }
3604
3605 static void __rbd_acknowledge_notify(struct rbd_device *rbd_dev,
3606                                      u64 notify_id, u64 cookie, s32 *result)
3607 {
3608         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
3609         int buf_size = 4 + CEPH_ENCODING_START_BLK_LEN;
3610         char buf[buf_size];
3611         int ret;
3612
3613         if (result) {
3614                 void *p = buf;
3615
3616                 /* encode ResponseMessage */
3617                 ceph_start_encoding(&p, 1, 1,
3618                                     buf_size - CEPH_ENCODING_START_BLK_LEN);
3619                 ceph_encode_32(&p, *result);
3620         } else {
3621                 buf_size = 0;
3622         }
3623
3624         ret = ceph_osdc_notify_ack(osdc, &rbd_dev->header_oid,
3625                                    &rbd_dev->header_oloc, notify_id, cookie,
3626                                    buf, buf_size);
3627         if (ret)
3628                 rbd_warn(rbd_dev, "acknowledge_notify failed: %d", ret);
3629 }
3630
3631 static void rbd_acknowledge_notify(struct rbd_device *rbd_dev, u64 notify_id,
3632                                    u64 cookie)
3633 {
3634         dout("%s rbd_dev %p\n", __func__, rbd_dev);
3635         __rbd_acknowledge_notify(rbd_dev, notify_id, cookie, NULL);
3636 }
3637
3638 static void rbd_acknowledge_notify_result(struct rbd_device *rbd_dev,
3639                                           u64 notify_id, u64 cookie, s32 result)
3640 {
3641         dout("%s rbd_dev %p result %d\n", __func__, rbd_dev, result);
3642         __rbd_acknowledge_notify(rbd_dev, notify_id, cookie, &result);
3643 }
3644
3645 static void rbd_watch_cb(void *arg, u64 notify_id, u64 cookie,
3646                          u64 notifier_id, void *data, size_t data_len)
3647 {
3648         struct rbd_device *rbd_dev = arg;
3649         void *p = data;
3650         void *const end = p + data_len;
3651         u8 struct_v = 0;
3652         u32 len;
3653         u32 notify_op;
3654         int ret;
3655
3656         dout("%s rbd_dev %p cookie %llu notify_id %llu data_len %zu\n",
3657              __func__, rbd_dev, cookie, notify_id, data_len);
3658         if (data_len) {
3659                 ret = ceph_start_decoding(&p, end, 1, "NotifyMessage",
3660                                           &struct_v, &len);
3661                 if (ret) {
3662                         rbd_warn(rbd_dev, "failed to decode NotifyMessage: %d",
3663                                  ret);
3664                         return;
3665                 }
3666
3667                 notify_op = ceph_decode_32(&p);
3668         } else {
3669                 /* legacy notification for header updates */
3670                 notify_op = RBD_NOTIFY_OP_HEADER_UPDATE;
3671                 len = 0;
3672         }
3673
3674         dout("%s rbd_dev %p notify_op %u\n", __func__, rbd_dev, notify_op);
3675         switch (notify_op) {
3676         case RBD_NOTIFY_OP_ACQUIRED_LOCK:
3677                 rbd_handle_acquired_lock(rbd_dev, struct_v, &p);
3678                 rbd_acknowledge_notify(rbd_dev, notify_id, cookie);
3679                 break;
3680         case RBD_NOTIFY_OP_RELEASED_LOCK:
3681                 rbd_handle_released_lock(rbd_dev, struct_v, &p);
3682                 rbd_acknowledge_notify(rbd_dev, notify_id, cookie);
3683                 break;
3684         case RBD_NOTIFY_OP_REQUEST_LOCK:
3685                 if (rbd_handle_request_lock(rbd_dev, struct_v, &p))
3686                         /*
3687                          * send ResponseMessage(0) back so the client
3688                          * can detect a missing owner
3689                          */
3690                         rbd_acknowledge_notify_result(rbd_dev, notify_id,
3691                                                       cookie, 0);
3692                 else
3693                         rbd_acknowledge_notify(rbd_dev, notify_id, cookie);
3694                 break;
3695         case RBD_NOTIFY_OP_HEADER_UPDATE:
3696                 ret = rbd_dev_refresh(rbd_dev);
3697                 if (ret)
3698                         rbd_warn(rbd_dev, "refresh failed: %d", ret);
3699
3700                 rbd_acknowledge_notify(rbd_dev, notify_id, cookie);
3701                 break;
3702         default:
3703                 if (rbd_is_lock_owner(rbd_dev))
3704                         rbd_acknowledge_notify_result(rbd_dev, notify_id,
3705                                                       cookie, -EOPNOTSUPP);
3706                 else
3707                         rbd_acknowledge_notify(rbd_dev, notify_id, cookie);
3708                 break;
3709         }
3710 }
3711
3712 static void __rbd_unregister_watch(struct rbd_device *rbd_dev);
3713
3714 static void rbd_watch_errcb(void *arg, u64 cookie, int err)
3715 {
3716         struct rbd_device *rbd_dev = arg;
3717
3718         rbd_warn(rbd_dev, "encountered watch error: %d", err);
3719
3720         down_write(&rbd_dev->lock_rwsem);
3721         rbd_set_owner_cid(rbd_dev, &rbd_empty_cid);
3722         up_write(&rbd_dev->lock_rwsem);
3723
3724         mutex_lock(&rbd_dev->watch_mutex);
3725         if (rbd_dev->watch_state == RBD_WATCH_STATE_REGISTERED) {
3726                 __rbd_unregister_watch(rbd_dev);
3727                 rbd_dev->watch_state = RBD_WATCH_STATE_ERROR;
3728
3729                 queue_delayed_work(rbd_dev->task_wq, &rbd_dev->watch_dwork, 0);
3730         }
3731         mutex_unlock(&rbd_dev->watch_mutex);
3732 }
3733
3734 /*
3735  * watch_mutex must be locked
3736  */
3737 static int __rbd_register_watch(struct rbd_device *rbd_dev)
3738 {
3739         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
3740         struct ceph_osd_linger_request *handle;
3741
3742         rbd_assert(!rbd_dev->watch_handle);
3743         dout("%s rbd_dev %p\n", __func__, rbd_dev);
3744
3745         handle = ceph_osdc_watch(osdc, &rbd_dev->header_oid,
3746                                  &rbd_dev->header_oloc, rbd_watch_cb,
3747                                  rbd_watch_errcb, rbd_dev);
3748         if (IS_ERR(handle))
3749                 return PTR_ERR(handle);
3750
3751         rbd_dev->watch_handle = handle;
3752         return 0;
3753 }
3754
3755 /*
3756  * watch_mutex must be locked
3757  */
3758 static void __rbd_unregister_watch(struct rbd_device *rbd_dev)
3759 {
3760         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
3761         int ret;
3762
3763         rbd_assert(rbd_dev->watch_handle);
3764         dout("%s rbd_dev %p\n", __func__, rbd_dev);
3765
3766         ret = ceph_osdc_unwatch(osdc, rbd_dev->watch_handle);
3767         if (ret)
3768                 rbd_warn(rbd_dev, "failed to unwatch: %d", ret);
3769
3770         rbd_dev->watch_handle = NULL;
3771 }
3772
3773 static int rbd_register_watch(struct rbd_device *rbd_dev)
3774 {
3775         int ret;
3776
3777         mutex_lock(&rbd_dev->watch_mutex);
3778         rbd_assert(rbd_dev->watch_state == RBD_WATCH_STATE_UNREGISTERED);
3779         ret = __rbd_register_watch(rbd_dev);
3780         if (ret)
3781                 goto out;
3782
3783         rbd_dev->watch_state = RBD_WATCH_STATE_REGISTERED;
3784         rbd_dev->watch_cookie = rbd_dev->watch_handle->linger_id;
3785
3786 out:
3787         mutex_unlock(&rbd_dev->watch_mutex);
3788         return ret;
3789 }
3790
3791 static void cancel_tasks_sync(struct rbd_device *rbd_dev)
3792 {
3793         dout("%s rbd_dev %p\n", __func__, rbd_dev);
3794
3795         cancel_delayed_work_sync(&rbd_dev->watch_dwork);
3796         cancel_work_sync(&rbd_dev->acquired_lock_work);
3797         cancel_work_sync(&rbd_dev->released_lock_work);
3798         cancel_delayed_work_sync(&rbd_dev->lock_dwork);
3799         cancel_work_sync(&rbd_dev->unlock_work);
3800 }
3801
3802 static void rbd_unregister_watch(struct rbd_device *rbd_dev)
3803 {
3804         WARN_ON(waitqueue_active(&rbd_dev->lock_waitq));
3805         cancel_tasks_sync(rbd_dev);
3806
3807         mutex_lock(&rbd_dev->watch_mutex);
3808         if (rbd_dev->watch_state == RBD_WATCH_STATE_REGISTERED)
3809                 __rbd_unregister_watch(rbd_dev);
3810         rbd_dev->watch_state = RBD_WATCH_STATE_UNREGISTERED;
3811         mutex_unlock(&rbd_dev->watch_mutex);
3812
3813         ceph_osdc_flush_notifies(&rbd_dev->rbd_client->client->osdc);
3814 }
3815
3816 static void rbd_reregister_watch(struct work_struct *work)
3817 {
3818         struct rbd_device *rbd_dev = container_of(to_delayed_work(work),
3819                                             struct rbd_device, watch_dwork);
3820         bool was_lock_owner = false;
3821         bool need_to_wake = false;
3822         int ret;
3823
3824         dout("%s rbd_dev %p\n", __func__, rbd_dev);
3825
3826         down_write(&rbd_dev->lock_rwsem);
3827         if (rbd_dev->lock_state == RBD_LOCK_STATE_LOCKED)
3828                 was_lock_owner = rbd_release_lock(rbd_dev);
3829
3830         mutex_lock(&rbd_dev->watch_mutex);
3831         if (rbd_dev->watch_state != RBD_WATCH_STATE_ERROR) {
3832                 mutex_unlock(&rbd_dev->watch_mutex);
3833                 goto out;
3834         }
3835
3836         ret = __rbd_register_watch(rbd_dev);
3837         if (ret) {
3838                 rbd_warn(rbd_dev, "failed to reregister watch: %d", ret);
3839                 if (ret == -EBLACKLISTED || ret == -ENOENT) {
3840                         set_bit(RBD_DEV_FLAG_BLACKLISTED, &rbd_dev->flags);
3841                         need_to_wake = true;
3842                 } else {
3843                         queue_delayed_work(rbd_dev->task_wq,
3844                                            &rbd_dev->watch_dwork,
3845                                            RBD_RETRY_DELAY);
3846                 }
3847                 mutex_unlock(&rbd_dev->watch_mutex);
3848                 goto out;
3849         }
3850
3851         need_to_wake = true;
3852         rbd_dev->watch_state = RBD_WATCH_STATE_REGISTERED;
3853         rbd_dev->watch_cookie = rbd_dev->watch_handle->linger_id;
3854         mutex_unlock(&rbd_dev->watch_mutex);
3855
3856         ret = rbd_dev_refresh(rbd_dev);
3857         if (ret)
3858                 rbd_warn(rbd_dev, "reregisteration refresh failed: %d", ret);
3859
3860         if (was_lock_owner) {
3861                 ret = rbd_try_lock(rbd_dev);
3862                 if (ret)
3863                         rbd_warn(rbd_dev, "reregisteration lock failed: %d",
3864                                  ret);
3865         }
3866
3867 out:
3868         up_write(&rbd_dev->lock_rwsem);
3869         if (need_to_wake)
3870                 wake_requests(rbd_dev, true);
3871 }
3872
3873 /*
3874  * Synchronous osd object method call.  Returns the number of bytes
3875  * returned in the outbound buffer, or a negative error code.
3876  */
3877 static int rbd_obj_method_sync(struct rbd_device *rbd_dev,
3878                              struct ceph_object_id *oid,
3879                              struct ceph_object_locator *oloc,
3880                              const char *method_name,
3881                              const void *outbound,
3882                              size_t outbound_size,
3883                              void *inbound,
3884                              size_t inbound_size)
3885 {
3886         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
3887         struct page *req_page = NULL;
3888         struct page *reply_page;
3889         int ret;
3890
3891         /*
3892          * Method calls are ultimately read operations.  The result
3893          * should placed into the inbound buffer provided.  They
3894          * also supply outbound data--parameters for the object
3895          * method.  Currently if this is present it will be a
3896          * snapshot id.
3897          */
3898         if (outbound) {
3899                 if (outbound_size > PAGE_SIZE)
3900                         return -E2BIG;
3901
3902                 req_page = alloc_page(GFP_KERNEL);
3903                 if (!req_page)
3904                         return -ENOMEM;
3905
3906                 memcpy(page_address(req_page), outbound, outbound_size);
3907         }
3908
3909         reply_page = alloc_page(GFP_KERNEL);
3910         if (!reply_page) {
3911                 if (req_page)
3912                         __free_page(req_page);
3913                 return -ENOMEM;
3914         }
3915
3916         ret = ceph_osdc_call(osdc, oid, oloc, RBD_DRV_NAME, method_name,
3917                              CEPH_OSD_FLAG_READ, req_page, outbound_size,
3918                              reply_page, &inbound_size);
3919         if (!ret) {
3920                 memcpy(inbound, page_address(reply_page), inbound_size);
3921                 ret = inbound_size;
3922         }
3923
3924         if (req_page)
3925                 __free_page(req_page);
3926         __free_page(reply_page);
3927         return ret;
3928 }
3929
3930 /*
3931  * lock_rwsem must be held for read
3932  */
3933 static void rbd_wait_state_locked(struct rbd_device *rbd_dev)
3934 {
3935         DEFINE_WAIT(wait);
3936
3937         do {
3938                 /*
3939                  * Note the use of mod_delayed_work() in rbd_acquire_lock()
3940                  * and cancel_delayed_work() in wake_requests().
3941                  */
3942                 dout("%s rbd_dev %p queueing lock_dwork\n", __func__, rbd_dev);
3943                 queue_delayed_work(rbd_dev->task_wq, &rbd_dev->lock_dwork, 0);
3944                 prepare_to_wait_exclusive(&rbd_dev->lock_waitq, &wait,
3945                                           TASK_UNINTERRUPTIBLE);
3946                 up_read(&rbd_dev->lock_rwsem);
3947                 schedule();
3948                 down_read(&rbd_dev->lock_rwsem);
3949         } while (rbd_dev->lock_state != RBD_LOCK_STATE_LOCKED &&
3950                  !test_bit(RBD_DEV_FLAG_BLACKLISTED, &rbd_dev->flags));
3951
3952         finish_wait(&rbd_dev->lock_waitq, &wait);
3953 }
3954
3955 static void rbd_queue_workfn(struct work_struct *work)
3956 {
3957         struct request *rq = blk_mq_rq_from_pdu(work);
3958         struct rbd_device *rbd_dev = rq->q->queuedata;
3959         struct rbd_img_request *img_request;
3960         struct ceph_snap_context *snapc = NULL;
3961         u64 offset = (u64)blk_rq_pos(rq) << SECTOR_SHIFT;
3962         u64 length = blk_rq_bytes(rq);
3963         enum obj_operation_type op_type;
3964         u64 mapping_size;
3965         bool must_be_locked;
3966         int result;
3967
3968         switch (req_op(rq)) {
3969         case REQ_OP_DISCARD:
3970                 op_type = OBJ_OP_DISCARD;
3971                 break;
3972         case REQ_OP_WRITE:
3973                 op_type = OBJ_OP_WRITE;
3974                 break;
3975         case REQ_OP_READ:
3976                 op_type = OBJ_OP_READ;
3977                 break;
3978         default:
3979                 dout("%s: non-fs request type %d\n", __func__, req_op(rq));
3980                 result = -EIO;
3981                 goto err;
3982         }
3983
3984         /* Ignore/skip any zero-length requests */
3985
3986         if (!length) {
3987                 dout("%s: zero-length request\n", __func__);
3988                 result = 0;
3989                 goto err_rq;
3990         }
3991
3992         /* Only reads are allowed to a read-only device */
3993
3994         if (op_type != OBJ_OP_READ) {
3995                 if (rbd_dev->mapping.read_only) {
3996                         result = -EROFS;
3997                         goto err_rq;
3998                 }
3999                 rbd_assert(rbd_dev->spec->snap_id == CEPH_NOSNAP);
4000         }
4001
4002         /*
4003          * Quit early if the mapped snapshot no longer exists.  It's
4004          * still possible the snapshot will have disappeared by the
4005          * time our request arrives at the osd, but there's no sense in
4006          * sending it if we already know.
4007          */
4008         if (!test_bit(RBD_DEV_FLAG_EXISTS, &rbd_dev->flags)) {
4009                 dout("request for non-existent snapshot");
4010                 rbd_assert(rbd_dev->spec->snap_id != CEPH_NOSNAP);
4011                 result = -ENXIO;
4012                 goto err_rq;
4013         }
4014
4015         if (offset && length > U64_MAX - offset + 1) {
4016                 rbd_warn(rbd_dev, "bad request range (%llu~%llu)", offset,
4017                          length);
4018                 result = -EINVAL;
4019                 goto err_rq;    /* Shouldn't happen */
4020         }
4021
4022         blk_mq_start_request(rq);
4023
4024         down_read(&rbd_dev->header_rwsem);
4025         mapping_size = rbd_dev->mapping.size;
4026         if (op_type != OBJ_OP_READ) {
4027                 snapc = rbd_dev->header.snapc;
4028                 ceph_get_snap_context(snapc);
4029                 must_be_locked = rbd_is_lock_supported(rbd_dev);
4030         } else {
4031                 must_be_locked = rbd_dev->opts->lock_on_read &&
4032                                         rbd_is_lock_supported(rbd_dev);
4033         }
4034         up_read(&rbd_dev->header_rwsem);
4035
4036         if (offset + length > mapping_size) {
4037                 rbd_warn(rbd_dev, "beyond EOD (%llu~%llu > %llu)", offset,
4038                          length, mapping_size);
4039                 result = -EIO;
4040                 goto err_rq;
4041         }
4042
4043         if (must_be_locked) {
4044                 down_read(&rbd_dev->lock_rwsem);
4045                 if (rbd_dev->lock_state != RBD_LOCK_STATE_LOCKED &&
4046                     !test_bit(RBD_DEV_FLAG_BLACKLISTED, &rbd_dev->flags))
4047                         rbd_wait_state_locked(rbd_dev);
4048
4049                 WARN_ON((rbd_dev->lock_state == RBD_LOCK_STATE_LOCKED) ^
4050                         !test_bit(RBD_DEV_FLAG_BLACKLISTED, &rbd_dev->flags));
4051                 if (test_bit(RBD_DEV_FLAG_BLACKLISTED, &rbd_dev->flags)) {
4052                         result = -EBLACKLISTED;
4053                         goto err_unlock;
4054                 }
4055         }
4056
4057         img_request = rbd_img_request_create(rbd_dev, offset, length, op_type,
4058                                              snapc);
4059         if (!img_request) {
4060                 result = -ENOMEM;
4061                 goto err_unlock;
4062         }
4063         img_request->rq = rq;
4064         snapc = NULL; /* img_request consumes a ref */
4065
4066         if (op_type == OBJ_OP_DISCARD)
4067                 result = rbd_img_request_fill(img_request, OBJ_REQUEST_NODATA,
4068                                               NULL);
4069         else
4070                 result = rbd_img_request_fill(img_request, OBJ_REQUEST_BIO,
4071                                               rq->bio);
4072         if (result)
4073                 goto err_img_request;
4074
4075         result = rbd_img_request_submit(img_request);
4076         if (result)
4077                 goto err_img_request;
4078
4079         if (must_be_locked)
4080                 up_read(&rbd_dev->lock_rwsem);
4081         return;
4082
4083 err_img_request:
4084         rbd_img_request_put(img_request);
4085 err_unlock:
4086         if (must_be_locked)
4087                 up_read(&rbd_dev->lock_rwsem);
4088 err_rq:
4089         if (result)
4090                 rbd_warn(rbd_dev, "%s %llx at %llx result %d",
4091                          obj_op_name(op_type), length, offset, result);
4092         ceph_put_snap_context(snapc);
4093 err:
4094         blk_mq_end_request(rq, result);
4095 }
4096
4097 static int rbd_queue_rq(struct blk_mq_hw_ctx *hctx,
4098                 const struct blk_mq_queue_data *bd)
4099 {
4100         struct request *rq = bd->rq;
4101         struct work_struct *work = blk_mq_rq_to_pdu(rq);
4102
4103         queue_work(rbd_wq, work);
4104         return BLK_MQ_RQ_QUEUE_OK;
4105 }
4106
4107 static void rbd_free_disk(struct rbd_device *rbd_dev)
4108 {
4109         struct gendisk *disk = rbd_dev->disk;
4110
4111         if (!disk)
4112                 return;
4113
4114         rbd_dev->disk = NULL;
4115         if (disk->flags & GENHD_FL_UP) {
4116                 del_gendisk(disk);
4117                 if (disk->queue)
4118                         blk_cleanup_queue(disk->queue);
4119                 blk_mq_free_tag_set(&rbd_dev->tag_set);
4120         }
4121         put_disk(disk);
4122 }
4123
4124 static int rbd_obj_read_sync(struct rbd_device *rbd_dev,
4125                              struct ceph_object_id *oid,
4126                              struct ceph_object_locator *oloc,
4127                              void *buf, int buf_len)
4128
4129 {
4130         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
4131         struct ceph_osd_request *req;
4132         struct page **pages;
4133         int num_pages = calc_pages_for(0, buf_len);
4134         int ret;
4135
4136         req = ceph_osdc_alloc_request(osdc, NULL, 1, false, GFP_KERNEL);
4137         if (!req)
4138                 return -ENOMEM;
4139
4140         ceph_oid_copy(&req->r_base_oid, oid);
4141         ceph_oloc_copy(&req->r_base_oloc, oloc);
4142         req->r_flags = CEPH_OSD_FLAG_READ;
4143
4144         ret = ceph_osdc_alloc_messages(req, GFP_KERNEL);
4145         if (ret)
4146                 goto out_req;
4147
4148         pages = ceph_alloc_page_vector(num_pages, GFP_KERNEL);
4149         if (IS_ERR(pages)) {
4150                 ret = PTR_ERR(pages);
4151                 goto out_req;
4152         }
4153
4154         osd_req_op_extent_init(req, 0, CEPH_OSD_OP_READ, 0, buf_len, 0, 0);
4155         osd_req_op_extent_osd_data_pages(req, 0, pages, buf_len, 0, false,
4156                                          true);
4157
4158         ceph_osdc_start_request(osdc, req, false);
4159         ret = ceph_osdc_wait_request(osdc, req);
4160         if (ret >= 0)
4161                 ceph_copy_from_page_vector(pages, buf, 0, ret);
4162
4163 out_req:
4164         ceph_osdc_put_request(req);
4165         return ret;
4166 }
4167
4168 /*
4169  * Read the complete header for the given rbd device.  On successful
4170  * return, the rbd_dev->header field will contain up-to-date
4171  * information about the image.
4172  */
4173 static int rbd_dev_v1_header_info(struct rbd_device *rbd_dev)
4174 {
4175         struct rbd_image_header_ondisk *ondisk = NULL;
4176         u32 snap_count = 0;
4177         u64 names_size = 0;
4178         u32 want_count;
4179         int ret;
4180
4181         /*
4182          * The complete header will include an array of its 64-bit
4183          * snapshot ids, followed by the names of those snapshots as
4184          * a contiguous block of NUL-terminated strings.  Note that
4185          * the number of snapshots could change by the time we read
4186          * it in, in which case we re-read it.
4187          */
4188         do {
4189                 size_t size;
4190
4191                 kfree(ondisk);
4192
4193                 size = sizeof (*ondisk);
4194                 size += snap_count * sizeof (struct rbd_image_snap_ondisk);
4195                 size += names_size;
4196                 ondisk = kmalloc(size, GFP_KERNEL);
4197                 if (!ondisk)
4198                         return -ENOMEM;
4199
4200                 ret = rbd_obj_read_sync(rbd_dev, &rbd_dev->header_oid,
4201                                         &rbd_dev->header_oloc, ondisk, size);
4202                 if (ret < 0)
4203                         goto out;
4204                 if ((size_t)ret < size) {
4205                         ret = -ENXIO;
4206                         rbd_warn(rbd_dev, "short header read (want %zd got %d)",
4207                                 size, ret);
4208                         goto out;
4209                 }
4210                 if (!rbd_dev_ondisk_valid(ondisk)) {
4211                         ret = -ENXIO;
4212                         rbd_warn(rbd_dev, "invalid header");
4213                         goto out;
4214                 }
4215
4216                 names_size = le64_to_cpu(ondisk->snap_names_len);
4217                 want_count = snap_count;
4218                 snap_count = le32_to_cpu(ondisk->snap_count);
4219         } while (snap_count != want_count);
4220
4221         ret = rbd_header_from_disk(rbd_dev, ondisk);
4222 out:
4223         kfree(ondisk);
4224
4225         return ret;
4226 }
4227
4228 /*
4229  * Clear the rbd device's EXISTS flag if the snapshot it's mapped to
4230  * has disappeared from the (just updated) snapshot context.
4231  */
4232 static void rbd_exists_validate(struct rbd_device *rbd_dev)
4233 {
4234         u64 snap_id;
4235
4236         if (!test_bit(RBD_DEV_FLAG_EXISTS, &rbd_dev->flags))
4237                 return;
4238
4239         snap_id = rbd_dev->spec->snap_id;
4240         if (snap_id == CEPH_NOSNAP)
4241                 return;
4242
4243         if (rbd_dev_snap_index(rbd_dev, snap_id) == BAD_SNAP_INDEX)
4244                 clear_bit(RBD_DEV_FLAG_EXISTS, &rbd_dev->flags);
4245 }
4246
4247 static void rbd_dev_update_size(struct rbd_device *rbd_dev)
4248 {
4249         sector_t size;
4250
4251         /*
4252          * If EXISTS is not set, rbd_dev->disk may be NULL, so don't
4253          * try to update its size.  If REMOVING is set, updating size
4254          * is just useless work since the device can't be opened.
4255          */
4256         if (test_bit(RBD_DEV_FLAG_EXISTS, &rbd_dev->flags) &&
4257             !test_bit(RBD_DEV_FLAG_REMOVING, &rbd_dev->flags)) {
4258                 size = (sector_t)rbd_dev->mapping.size / SECTOR_SIZE;
4259                 dout("setting size to %llu sectors", (unsigned long long)size);
4260                 set_capacity(rbd_dev->disk, size);
4261                 revalidate_disk(rbd_dev->disk);
4262         }
4263 }
4264
4265 static int rbd_dev_refresh(struct rbd_device *rbd_dev)
4266 {
4267         u64 mapping_size;
4268         int ret;
4269
4270         down_write(&rbd_dev->header_rwsem);
4271         mapping_size = rbd_dev->mapping.size;
4272
4273         ret = rbd_dev_header_info(rbd_dev);
4274         if (ret)
4275                 goto out;
4276
4277         /*
4278          * If there is a parent, see if it has disappeared due to the
4279          * mapped image getting flattened.
4280          */
4281         if (rbd_dev->parent) {
4282                 ret = rbd_dev_v2_parent_info(rbd_dev);
4283                 if (ret)
4284                         goto out;
4285         }
4286
4287         if (rbd_dev->spec->snap_id == CEPH_NOSNAP) {
4288                 rbd_dev->mapping.size = rbd_dev->header.image_size;
4289         } else {
4290                 /* validate mapped snapshot's EXISTS flag */
4291                 rbd_exists_validate(rbd_dev);
4292         }
4293
4294 out:
4295         up_write(&rbd_dev->header_rwsem);
4296         if (!ret && mapping_size != rbd_dev->mapping.size)
4297                 rbd_dev_update_size(rbd_dev);
4298
4299         return ret;
4300 }
4301
4302 static int rbd_init_request(void *data, struct request *rq,
4303                 unsigned int hctx_idx, unsigned int request_idx,
4304                 unsigned int numa_node)
4305 {
4306         struct work_struct *work = blk_mq_rq_to_pdu(rq);
4307
4308         INIT_WORK(work, rbd_queue_workfn);
4309         return 0;
4310 }
4311
4312 static struct blk_mq_ops rbd_mq_ops = {
4313         .queue_rq       = rbd_queue_rq,
4314         .init_request   = rbd_init_request,
4315 };
4316
4317 static int rbd_init_disk(struct rbd_device *rbd_dev)
4318 {
4319         struct gendisk *disk;
4320         struct request_queue *q;
4321         u64 segment_size;
4322         int err;
4323
4324         /* create gendisk info */
4325         disk = alloc_disk(single_major ?
4326                           (1 << RBD_SINGLE_MAJOR_PART_SHIFT) :
4327                           RBD_MINORS_PER_MAJOR);
4328         if (!disk)
4329                 return -ENOMEM;
4330
4331         snprintf(disk->disk_name, sizeof(disk->disk_name), RBD_DRV_NAME "%d",
4332                  rbd_dev->dev_id);
4333         disk->major = rbd_dev->major;
4334         disk->first_minor = rbd_dev->minor;
4335         if (single_major)
4336                 disk->flags |= GENHD_FL_EXT_DEVT;
4337         disk->fops = &rbd_bd_ops;
4338         disk->private_data = rbd_dev;
4339
4340         memset(&rbd_dev->tag_set, 0, sizeof(rbd_dev->tag_set));
4341         rbd_dev->tag_set.ops = &rbd_mq_ops;
4342         rbd_dev->tag_set.queue_depth = rbd_dev->opts->queue_depth;
4343         rbd_dev->tag_set.numa_node = NUMA_NO_NODE;
4344         rbd_dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
4345         rbd_dev->tag_set.nr_hw_queues = 1;
4346         rbd_dev->tag_set.cmd_size = sizeof(struct work_struct);
4347
4348         err = blk_mq_alloc_tag_set(&rbd_dev->tag_set);
4349         if (err)
4350                 goto out_disk;
4351
4352         q = blk_mq_init_queue(&rbd_dev->tag_set);
4353         if (IS_ERR(q)) {
4354                 err = PTR_ERR(q);
4355                 goto out_tag_set;
4356         }
4357
4358         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
4359         /* QUEUE_FLAG_ADD_RANDOM is off by default for blk-mq */
4360
4361         /* set io sizes to object size */
4362         segment_size = rbd_obj_bytes(&rbd_dev->header);
4363         blk_queue_max_hw_sectors(q, segment_size / SECTOR_SIZE);
4364         q->limits.max_sectors = queue_max_hw_sectors(q);
4365         blk_queue_max_segments(q, segment_size / SECTOR_SIZE);
4366         blk_queue_max_segment_size(q, segment_size);
4367         blk_queue_io_min(q, segment_size);
4368         blk_queue_io_opt(q, segment_size);
4369
4370         /* enable the discard support */
4371         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
4372         q->limits.discard_granularity = segment_size;
4373         q->limits.discard_alignment = segment_size;
4374         blk_queue_max_discard_sectors(q, segment_size / SECTOR_SIZE);
4375         q->limits.discard_zeroes_data = 1;
4376
4377         if (!ceph_test_opt(rbd_dev->rbd_client->client, NOCRC))
4378                 q->backing_dev_info->capabilities |= BDI_CAP_STABLE_WRITES;
4379
4380         disk->queue = q;
4381
4382         q->queuedata = rbd_dev;
4383
4384         rbd_dev->disk = disk;
4385
4386         return 0;
4387 out_tag_set:
4388         blk_mq_free_tag_set(&rbd_dev->tag_set);
4389 out_disk:
4390         put_disk(disk);
4391         return err;
4392 }
4393
4394 /*
4395   sysfs
4396 */
4397
4398 static struct rbd_device *dev_to_rbd_dev(struct device *dev)
4399 {
4400         return container_of(dev, struct rbd_device, dev);
4401 }
4402
4403 static ssize_t rbd_size_show(struct device *dev,
4404                              struct device_attribute *attr, char *buf)
4405 {
4406         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
4407
4408         return sprintf(buf, "%llu\n",
4409                 (unsigned long long)rbd_dev->mapping.size);
4410 }
4411
4412 /*
4413  * Note this shows the features for whatever's mapped, which is not
4414  * necessarily the base image.
4415  */
4416 static ssize_t rbd_features_show(struct device *dev,
4417                              struct device_attribute *attr, char *buf)
4418 {
4419         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
4420
4421         return sprintf(buf, "0x%016llx\n",
4422                         (unsigned long long)rbd_dev->mapping.features);
4423 }
4424
4425 static ssize_t rbd_major_show(struct device *dev,
4426                               struct device_attribute *attr, char *buf)
4427 {
4428         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
4429
4430         if (rbd_dev->major)
4431                 return sprintf(buf, "%d\n", rbd_dev->major);
4432
4433         return sprintf(buf, "(none)\n");
4434 }
4435
4436 static ssize_t rbd_minor_show(struct device *dev,
4437                               struct device_attribute *attr, char *buf)
4438 {
4439         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
4440
4441         return sprintf(buf, "%d\n", rbd_dev->minor);
4442 }
4443
4444 static ssize_t rbd_client_addr_show(struct device *dev,
4445                                     struct device_attribute *attr, char *buf)
4446 {
4447         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
4448         struct ceph_entity_addr *client_addr =
4449             ceph_client_addr(rbd_dev->rbd_client->client);
4450
4451         return sprintf(buf, "%pISpc/%u\n", &client_addr->in_addr,
4452                        le32_to_cpu(client_addr->nonce));
4453 }
4454
4455 static ssize_t rbd_client_id_show(struct device *dev,
4456                                   struct device_attribute *attr, char *buf)
4457 {
4458         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
4459
4460         return sprintf(buf, "client%lld\n",
4461                        ceph_client_gid(rbd_dev->rbd_client->client));
4462 }
4463
4464 static ssize_t rbd_cluster_fsid_show(struct device *dev,
4465                                      struct device_attribute *attr, char *buf)
4466 {
4467         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
4468
4469         return sprintf(buf, "%pU\n", &rbd_dev->rbd_client->client->fsid);
4470 }
4471
4472 static ssize_t rbd_config_info_show(struct device *dev,
4473                                     struct device_attribute *attr, char *buf)
4474 {
4475         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
4476
4477         return sprintf(buf, "%s\n", rbd_dev->config_info);
4478 }
4479
4480 static ssize_t rbd_pool_show(struct device *dev,
4481                              struct device_attribute *attr, char *buf)
4482 {
4483         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
4484
4485         return sprintf(buf, "%s\n", rbd_dev->spec->pool_name);
4486 }
4487
4488 static ssize_t rbd_pool_id_show(struct device *dev,
4489                              struct device_attribute *attr, char *buf)
4490 {
4491         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
4492
4493         return sprintf(buf, "%llu\n",
4494                         (unsigned long long) rbd_dev->spec->pool_id);
4495 }
4496
4497 static ssize_t rbd_name_show(struct device *dev,
4498                              struct device_attribute *attr, char *buf)
4499 {
4500         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
4501
4502         if (rbd_dev->spec->image_name)
4503                 return sprintf(buf, "%s\n", rbd_dev->spec->image_name);
4504
4505         return sprintf(buf, "(unknown)\n");
4506 }
4507
4508 static ssize_t rbd_image_id_show(struct device *dev,
4509                              struct device_attribute *attr, char *buf)
4510 {
4511         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
4512
4513         return sprintf(buf, "%s\n", rbd_dev->spec->image_id);
4514 }
4515
4516 /*
4517  * Shows the name of the currently-mapped snapshot (or
4518  * RBD_SNAP_HEAD_NAME for the base image).
4519  */
4520 static ssize_t rbd_snap_show(struct device *dev,
4521                              struct device_attribute *attr,
4522                              char *buf)
4523 {
4524         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
4525
4526         return sprintf(buf, "%s\n", rbd_dev->spec->snap_name);
4527 }
4528
4529 static ssize_t rbd_snap_id_show(struct device *dev,
4530                                 struct device_attribute *attr, char *buf)
4531 {
4532         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
4533
4534         return sprintf(buf, "%llu\n", rbd_dev->spec->snap_id);
4535 }
4536
4537 /*
4538  * For a v2 image, shows the chain of parent images, separated by empty
4539  * lines.  For v1 images or if there is no parent, shows "(no parent
4540  * image)".
4541  */
4542 static ssize_t rbd_parent_show(struct device *dev,
4543                                struct device_attribute *attr,
4544                                char *buf)
4545 {
4546         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
4547         ssize_t count = 0;
4548
4549         if (!rbd_dev->parent)
4550                 return sprintf(buf, "(no parent image)\n");
4551
4552         for ( ; rbd_dev->parent; rbd_dev = rbd_dev->parent) {
4553                 struct rbd_spec *spec = rbd_dev->parent_spec;
4554
4555                 count += sprintf(&buf[count], "%s"
4556                             "pool_id %llu\npool_name %s\n"
4557                             "image_id %s\nimage_name %s\n"
4558                             "snap_id %llu\nsnap_name %s\n"
4559                             "overlap %llu\n",
4560                             !count ? "" : "\n", /* first? */
4561                             spec->pool_id, spec->pool_name,
4562                             spec->image_id, spec->image_name ?: "(unknown)",
4563                             spec->snap_id, spec->snap_name,
4564                             rbd_dev->parent_overlap);
4565         }
4566
4567         return count;
4568 }
4569
4570 static ssize_t rbd_image_refresh(struct device *dev,
4571                                  struct device_attribute *attr,
4572                                  const char *buf,
4573                                  size_t size)
4574 {
4575         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
4576         int ret;
4577
4578         ret = rbd_dev_refresh(rbd_dev);
4579         if (ret)
4580                 return ret;
4581
4582         return size;
4583 }
4584
4585 static DEVICE_ATTR(size, S_IRUGO, rbd_size_show, NULL);
4586 static DEVICE_ATTR(features, S_IRUGO, rbd_features_show, NULL);
4587 static DEVICE_ATTR(major, S_IRUGO, rbd_major_show, NULL);
4588 static DEVICE_ATTR(minor, S_IRUGO, rbd_minor_show, NULL);
4589 static DEVICE_ATTR(client_addr, S_IRUGO, rbd_client_addr_show, NULL);
4590 static DEVICE_ATTR(client_id, S_IRUGO, rbd_client_id_show, NULL);
4591 static DEVICE_ATTR(cluster_fsid, S_IRUGO, rbd_cluster_fsid_show, NULL);
4592 static DEVICE_ATTR(config_info, S_IRUSR, rbd_config_info_show, NULL);
4593 static DEVICE_ATTR(pool, S_IRUGO, rbd_pool_show, NULL);
4594 static DEVICE_ATTR(pool_id, S_IRUGO, rbd_pool_id_show, NULL);
4595 static DEVICE_ATTR(name, S_IRUGO, rbd_name_show, NULL);
4596 static DEVICE_ATTR(image_id, S_IRUGO, rbd_image_id_show, NULL);
4597 static DEVICE_ATTR(refresh, S_IWUSR, NULL, rbd_image_refresh);
4598 static DEVICE_ATTR(current_snap, S_IRUGO, rbd_snap_show, NULL);
4599 static DEVICE_ATTR(snap_id, S_IRUGO, rbd_snap_id_show, NULL);
4600 static DEVICE_ATTR(parent, S_IRUGO, rbd_parent_show, NULL);
4601
4602 static struct attribute *rbd_attrs[] = {
4603         &dev_attr_size.attr,
4604         &dev_attr_features.attr,
4605         &dev_attr_major.attr,
4606         &dev_attr_minor.attr,
4607         &dev_attr_client_addr.attr,
4608         &dev_attr_client_id.attr,
4609         &dev_attr_cluster_fsid.attr,
4610         &dev_attr_config_info.attr,
4611         &dev_attr_pool.attr,
4612         &dev_attr_pool_id.attr,
4613         &dev_attr_name.attr,
4614         &dev_attr_image_id.attr,
4615         &dev_attr_current_snap.attr,
4616         &dev_attr_snap_id.attr,
4617         &dev_attr_parent.attr,
4618         &dev_attr_refresh.attr,
4619         NULL
4620 };
4621
4622 static struct attribute_group rbd_attr_group = {
4623         .attrs = rbd_attrs,
4624 };
4625
4626 static const struct attribute_group *rbd_attr_groups[] = {
4627         &rbd_attr_group,
4628         NULL
4629 };
4630
4631 static void rbd_dev_release(struct device *dev);
4632
4633 static const struct device_type rbd_device_type = {
4634         .name           = "rbd",
4635         .groups         = rbd_attr_groups,
4636         .release        = rbd_dev_release,
4637 };
4638
4639 static struct rbd_spec *rbd_spec_get(struct rbd_spec *spec)
4640 {
4641         kref_get(&spec->kref);
4642
4643         return spec;
4644 }
4645
4646 static void rbd_spec_free(struct kref *kref);
4647 static void rbd_spec_put(struct rbd_spec *spec)
4648 {
4649         if (spec)
4650                 kref_put(&spec->kref, rbd_spec_free);
4651 }
4652
4653 static struct rbd_spec *rbd_spec_alloc(void)
4654 {
4655         struct rbd_spec *spec;
4656
4657         spec = kzalloc(sizeof (*spec), GFP_KERNEL);
4658         if (!spec)
4659                 return NULL;
4660
4661         spec->pool_id = CEPH_NOPOOL;
4662         spec->snap_id = CEPH_NOSNAP;
4663         kref_init(&spec->kref);
4664
4665         return spec;
4666 }
4667
4668 static void rbd_spec_free(struct kref *kref)
4669 {
4670         struct rbd_spec *spec = container_of(kref, struct rbd_spec, kref);
4671
4672         kfree(spec->pool_name);
4673         kfree(spec->image_id);
4674         kfree(spec->image_name);
4675         kfree(spec->snap_name);
4676         kfree(spec);
4677 }
4678
4679 static void rbd_dev_free(struct rbd_device *rbd_dev)
4680 {
4681         WARN_ON(rbd_dev->watch_state != RBD_WATCH_STATE_UNREGISTERED);
4682         WARN_ON(rbd_dev->lock_state != RBD_LOCK_STATE_UNLOCKED);
4683
4684         ceph_oid_destroy(&rbd_dev->header_oid);
4685         ceph_oloc_destroy(&rbd_dev->header_oloc);
4686         kfree(rbd_dev->config_info);
4687
4688         rbd_put_client(rbd_dev->rbd_client);
4689         rbd_spec_put(rbd_dev->spec);
4690         kfree(rbd_dev->opts);
4691         kfree(rbd_dev);
4692 }
4693
4694 static void rbd_dev_release(struct device *dev)
4695 {
4696         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
4697         bool need_put = !!rbd_dev->opts;
4698
4699         if (need_put) {
4700                 destroy_workqueue(rbd_dev->task_wq);
4701                 ida_simple_remove(&rbd_dev_id_ida, rbd_dev->dev_id);
4702         }
4703
4704         rbd_dev_free(rbd_dev);
4705
4706         /*
4707          * This is racy, but way better than putting module outside of
4708          * the release callback.  The race window is pretty small, so
4709          * doing something similar to dm (dm-builtin.c) is overkill.
4710          */
4711         if (need_put)
4712                 module_put(THIS_MODULE);
4713 }
4714
4715 static struct rbd_device *__rbd_dev_create(struct rbd_client *rbdc,
4716                                            struct rbd_spec *spec)
4717 {
4718         struct rbd_device *rbd_dev;
4719
4720         rbd_dev = kzalloc(sizeof(*rbd_dev), GFP_KERNEL);
4721         if (!rbd_dev)
4722                 return NULL;
4723
4724         spin_lock_init(&rbd_dev->lock);
4725         INIT_LIST_HEAD(&rbd_dev->node);
4726         init_rwsem(&rbd_dev->header_rwsem);
4727
4728         rbd_dev->header.data_pool_id = CEPH_NOPOOL;
4729         ceph_oid_init(&rbd_dev->header_oid);
4730         rbd_dev->header_oloc.pool = spec->pool_id;
4731
4732         mutex_init(&rbd_dev->watch_mutex);
4733         rbd_dev->watch_state = RBD_WATCH_STATE_UNREGISTERED;
4734         INIT_DELAYED_WORK(&rbd_dev->watch_dwork, rbd_reregister_watch);
4735
4736         init_rwsem(&rbd_dev->lock_rwsem);
4737         rbd_dev->lock_state = RBD_LOCK_STATE_UNLOCKED;
4738         INIT_WORK(&rbd_dev->acquired_lock_work, rbd_notify_acquired_lock);
4739         INIT_WORK(&rbd_dev->released_lock_work, rbd_notify_released_lock);
4740         INIT_DELAYED_WORK(&rbd_dev->lock_dwork, rbd_acquire_lock);
4741         INIT_WORK(&rbd_dev->unlock_work, rbd_release_lock_work);
4742         init_waitqueue_head(&rbd_dev->lock_waitq);
4743
4744         rbd_dev->dev.bus = &rbd_bus_type;
4745         rbd_dev->dev.type = &rbd_device_type;
4746         rbd_dev->dev.parent = &rbd_root_dev;
4747         device_initialize(&rbd_dev->dev);
4748
4749         rbd_dev->rbd_client = rbdc;
4750         rbd_dev->spec = spec;
4751
4752         return rbd_dev;
4753 }
4754
4755 /*
4756  * Create a mapping rbd_dev.
4757  */
4758 static struct rbd_device *rbd_dev_create(struct rbd_client *rbdc,
4759                                          struct rbd_spec *spec,
4760                                          struct rbd_options *opts)
4761 {
4762         struct rbd_device *rbd_dev;
4763
4764         rbd_dev = __rbd_dev_create(rbdc, spec);
4765         if (!rbd_dev)
4766                 return NULL;
4767
4768         rbd_dev->opts = opts;
4769
4770         /* get an id and fill in device name */
4771         rbd_dev->dev_id = ida_simple_get(&rbd_dev_id_ida, 0,
4772                                          minor_to_rbd_dev_id(1 << MINORBITS),
4773                                          GFP_KERNEL);
4774         if (rbd_dev->dev_id < 0)
4775                 goto fail_rbd_dev;
4776
4777         sprintf(rbd_dev->name, RBD_DRV_NAME "%d", rbd_dev->dev_id);
4778         rbd_dev->task_wq = alloc_ordered_workqueue("%s-tasks", WQ_MEM_RECLAIM,
4779                                                    rbd_dev->name);
4780         if (!rbd_dev->task_wq)
4781                 goto fail_dev_id;
4782
4783         /* we have a ref from do_rbd_add() */
4784         __module_get(THIS_MODULE);
4785
4786         dout("%s rbd_dev %p dev_id %d\n", __func__, rbd_dev, rbd_dev->dev_id);
4787         return rbd_dev;
4788
4789 fail_dev_id:
4790         ida_simple_remove(&rbd_dev_id_ida, rbd_dev->dev_id);
4791 fail_rbd_dev:
4792         rbd_dev_free(rbd_dev);
4793         return NULL;
4794 }
4795
4796 static void rbd_dev_destroy(struct rbd_device *rbd_dev)
4797 {
4798         if (rbd_dev)
4799                 put_device(&rbd_dev->dev);
4800 }
4801
4802 /*
4803  * Get the size and object order for an image snapshot, or if
4804  * snap_id is CEPH_NOSNAP, gets this information for the base
4805  * image.
4806  */
4807 static int _rbd_dev_v2_snap_size(struct rbd_device *rbd_dev, u64 snap_id,
4808                                 u8 *order, u64 *snap_size)
4809 {
4810         __le64 snapid = cpu_to_le64(snap_id);
4811         int ret;
4812         struct {
4813                 u8 order;
4814                 __le64 size;
4815         } __attribute__ ((packed)) size_buf = { 0 };
4816
4817         ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
4818                                   &rbd_dev->header_oloc, "get_size",
4819                                   &snapid, sizeof(snapid),
4820                                   &size_buf, sizeof(size_buf));
4821         dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
4822         if (ret < 0)
4823                 return ret;
4824         if (ret < sizeof (size_buf))
4825                 return -ERANGE;
4826
4827         if (order) {
4828                 *order = size_buf.order;
4829                 dout("  order %u", (unsigned int)*order);
4830         }
4831         *snap_size = le64_to_cpu(size_buf.size);
4832
4833         dout("  snap_id 0x%016llx snap_size = %llu\n",
4834                 (unsigned long long)snap_id,
4835                 (unsigned long long)*snap_size);
4836
4837         return 0;
4838 }
4839
4840 static int rbd_dev_v2_image_size(struct rbd_device *rbd_dev)
4841 {
4842         return _rbd_dev_v2_snap_size(rbd_dev, CEPH_NOSNAP,
4843                                         &rbd_dev->header.obj_order,
4844                                         &rbd_dev->header.image_size);
4845 }
4846
4847 static int rbd_dev_v2_object_prefix(struct rbd_device *rbd_dev)
4848 {
4849         void *reply_buf;
4850         int ret;
4851         void *p;
4852
4853         reply_buf = kzalloc(RBD_OBJ_PREFIX_LEN_MAX, GFP_KERNEL);
4854         if (!reply_buf)
4855                 return -ENOMEM;
4856
4857         ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
4858                                   &rbd_dev->header_oloc, "get_object_prefix",
4859                                   NULL, 0, reply_buf, RBD_OBJ_PREFIX_LEN_MAX);
4860         dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
4861         if (ret < 0)
4862                 goto out;
4863
4864         p = reply_buf;
4865         rbd_dev->header.object_prefix = ceph_extract_encoded_string(&p,
4866                                                 p + ret, NULL, GFP_NOIO);
4867         ret = 0;
4868
4869         if (IS_ERR(rbd_dev->header.object_prefix)) {
4870                 ret = PTR_ERR(rbd_dev->header.object_prefix);
4871                 rbd_dev->header.object_prefix = NULL;
4872         } else {
4873                 dout("  object_prefix = %s\n", rbd_dev->header.object_prefix);
4874         }
4875 out:
4876         kfree(reply_buf);
4877
4878         return ret;
4879 }
4880
4881 static int _rbd_dev_v2_snap_features(struct rbd_device *rbd_dev, u64 snap_id,
4882                 u64 *snap_features)
4883 {
4884         __le64 snapid = cpu_to_le64(snap_id);
4885         struct {
4886                 __le64 features;
4887                 __le64 incompat;
4888         } __attribute__ ((packed)) features_buf = { 0 };
4889         u64 unsup;
4890         int ret;
4891
4892         ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
4893                                   &rbd_dev->header_oloc, "get_features",
4894                                   &snapid, sizeof(snapid),
4895                                   &features_buf, sizeof(features_buf));
4896         dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
4897         if (ret < 0)
4898                 return ret;
4899         if (ret < sizeof (features_buf))
4900                 return -ERANGE;
4901
4902         unsup = le64_to_cpu(features_buf.incompat) & ~RBD_FEATURES_SUPPORTED;
4903         if (unsup) {
4904                 rbd_warn(rbd_dev, "image uses unsupported features: 0x%llx",
4905                          unsup);
4906                 return -ENXIO;
4907         }
4908
4909         *snap_features = le64_to_cpu(features_buf.features);
4910
4911         dout("  snap_id 0x%016llx features = 0x%016llx incompat = 0x%016llx\n",
4912                 (unsigned long long)snap_id,
4913                 (unsigned long long)*snap_features,
4914                 (unsigned long long)le64_to_cpu(features_buf.incompat));
4915
4916         return 0;
4917 }
4918
4919 static int rbd_dev_v2_features(struct rbd_device *rbd_dev)
4920 {
4921         return _rbd_dev_v2_snap_features(rbd_dev, CEPH_NOSNAP,
4922                                                 &rbd_dev->header.features);
4923 }
4924
4925 static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev)
4926 {
4927         struct rbd_spec *parent_spec;
4928         size_t size;
4929         void *reply_buf = NULL;
4930         __le64 snapid;
4931         void *p;
4932         void *end;
4933         u64 pool_id;
4934         char *image_id;
4935         u64 snap_id;
4936         u64 overlap;
4937         int ret;
4938
4939         parent_spec = rbd_spec_alloc();
4940         if (!parent_spec)
4941                 return -ENOMEM;
4942
4943         size = sizeof (__le64) +                                /* pool_id */
4944                 sizeof (__le32) + RBD_IMAGE_ID_LEN_MAX +        /* image_id */
4945                 sizeof (__le64) +                               /* snap_id */
4946                 sizeof (__le64);                                /* overlap */
4947         reply_buf = kmalloc(size, GFP_KERNEL);
4948         if (!reply_buf) {
4949                 ret = -ENOMEM;
4950                 goto out_err;
4951         }
4952
4953         snapid = cpu_to_le64(rbd_dev->spec->snap_id);
4954         ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
4955                                   &rbd_dev->header_oloc, "get_parent",
4956                                   &snapid, sizeof(snapid), reply_buf, size);
4957         dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
4958         if (ret < 0)
4959                 goto out_err;
4960
4961         p = reply_buf;
4962         end = reply_buf + ret;
4963         ret = -ERANGE;
4964         ceph_decode_64_safe(&p, end, pool_id, out_err);
4965         if (pool_id == CEPH_NOPOOL) {
4966                 /*
4967                  * Either the parent never existed, or we have
4968                  * record of it but the image got flattened so it no
4969                  * longer has a parent.  When the parent of a
4970                  * layered image disappears we immediately set the
4971                  * overlap to 0.  The effect of this is that all new
4972                  * requests will be treated as if the image had no
4973                  * parent.
4974                  */
4975                 if (rbd_dev->parent_overlap) {
4976                         rbd_dev->parent_overlap = 0;
4977                         rbd_dev_parent_put(rbd_dev);
4978                         pr_info("%s: clone image has been flattened\n",
4979                                 rbd_dev->disk->disk_name);
4980                 }
4981
4982                 goto out;       /* No parent?  No problem. */
4983         }
4984
4985         /* The ceph file layout needs to fit pool id in 32 bits */
4986
4987         ret = -EIO;
4988         if (pool_id > (u64)U32_MAX) {
4989                 rbd_warn(NULL, "parent pool id too large (%llu > %u)",
4990                         (unsigned long long)pool_id, U32_MAX);
4991                 goto out_err;
4992         }
4993
4994         image_id = ceph_extract_encoded_string(&p, end, NULL, GFP_KERNEL);
4995         if (IS_ERR(image_id)) {
4996                 ret = PTR_ERR(image_id);
4997                 goto out_err;
4998         }
4999         ceph_decode_64_safe(&p, end, snap_id, out_err);
5000         ceph_decode_64_safe(&p, end, overlap, out_err);
5001
5002         /*
5003          * The parent won't change (except when the clone is
5004          * flattened, already handled that).  So we only need to
5005          * record the parent spec we have not already done so.
5006          */
5007         if (!rbd_dev->parent_spec) {
5008                 parent_spec->pool_id = pool_id;
5009                 parent_spec->image_id = image_id;
5010                 parent_spec->snap_id = snap_id;
5011                 rbd_dev->parent_spec = parent_spec;
5012                 parent_spec = NULL;     /* rbd_dev now owns this */
5013         } else {
5014                 kfree(image_id);
5015         }
5016
5017         /*
5018          * We always update the parent overlap.  If it's zero we issue
5019          * a warning, as we will proceed as if there was no parent.
5020          */
5021         if (!overlap) {
5022                 if (parent_spec) {
5023                         /* refresh, careful to warn just once */
5024                         if (rbd_dev->parent_overlap)
5025                                 rbd_warn(rbd_dev,
5026                                     "clone now standalone (overlap became 0)");
5027                 } else {
5028                         /* initial probe */
5029                         rbd_warn(rbd_dev, "clone is standalone (overlap 0)");
5030                 }
5031         }
5032         rbd_dev->parent_overlap = overlap;
5033
5034 out:
5035         ret = 0;
5036 out_err:
5037         kfree(reply_buf);
5038         rbd_spec_put(parent_spec);
5039
5040         return ret;
5041 }
5042
5043 static int rbd_dev_v2_striping_info(struct rbd_device *rbd_dev)
5044 {
5045         struct {
5046                 __le64 stripe_unit;
5047                 __le64 stripe_count;
5048         } __attribute__ ((packed)) striping_info_buf = { 0 };
5049         size_t size = sizeof (striping_info_buf);
5050         void *p;
5051         u64 obj_size;
5052         u64 stripe_unit;
5053         u64 stripe_count;
5054         int ret;
5055
5056         ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
5057                                 &rbd_dev->header_oloc, "get_stripe_unit_count",
5058                                 NULL, 0, &striping_info_buf, size);
5059         dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
5060         if (ret < 0)
5061                 return ret;
5062         if (ret < size)
5063                 return -ERANGE;
5064
5065         /*
5066          * We don't actually support the "fancy striping" feature
5067          * (STRIPINGV2) yet, but if the striping sizes are the
5068          * defaults the behavior is the same as before.  So find
5069          * out, and only fail if the image has non-default values.
5070          */
5071         ret = -EINVAL;
5072         obj_size = rbd_obj_bytes(&rbd_dev->header);
5073         p = &striping_info_buf;
5074         stripe_unit = ceph_decode_64(&p);
5075         if (stripe_unit != obj_size) {
5076                 rbd_warn(rbd_dev, "unsupported stripe unit "
5077                                 "(got %llu want %llu)",
5078                                 stripe_unit, obj_size);
5079                 return -EINVAL;
5080         }
5081         stripe_count = ceph_decode_64(&p);
5082         if (stripe_count != 1) {
5083                 rbd_warn(rbd_dev, "unsupported stripe count "
5084                                 "(got %llu want 1)", stripe_count);
5085                 return -EINVAL;
5086         }
5087         rbd_dev->header.stripe_unit = stripe_unit;
5088         rbd_dev->header.stripe_count = stripe_count;
5089
5090         return 0;
5091 }
5092
5093 static int rbd_dev_v2_data_pool(struct rbd_device *rbd_dev)
5094 {
5095         __le64 data_pool_id;
5096         int ret;
5097
5098         ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
5099                                   &rbd_dev->header_oloc, "get_data_pool",
5100                                   NULL, 0, &data_pool_id, sizeof(data_pool_id));
5101         if (ret < 0)
5102                 return ret;
5103         if (ret < sizeof(data_pool_id))
5104                 return -EBADMSG;
5105
5106         rbd_dev->header.data_pool_id = le64_to_cpu(data_pool_id);
5107         WARN_ON(rbd_dev->header.data_pool_id == CEPH_NOPOOL);
5108         return 0;
5109 }
5110
5111 static char *rbd_dev_image_name(struct rbd_device *rbd_dev)
5112 {
5113         CEPH_DEFINE_OID_ONSTACK(oid);
5114         size_t image_id_size;
5115         char *image_id;
5116         void *p;
5117         void *end;
5118         size_t size;
5119         void *reply_buf = NULL;
5120         size_t len = 0;
5121         char *image_name = NULL;
5122         int ret;
5123
5124         rbd_assert(!rbd_dev->spec->image_name);
5125
5126         len = strlen(rbd_dev->spec->image_id);
5127         image_id_size = sizeof (__le32) + len;
5128         image_id = kmalloc(image_id_size, GFP_KERNEL);
5129         if (!image_id)
5130                 return NULL;
5131
5132         p = image_id;
5133         end = image_id + image_id_size;
5134         ceph_encode_string(&p, end, rbd_dev->spec->image_id, (u32)len);
5135
5136         size = sizeof (__le32) + RBD_IMAGE_NAME_LEN_MAX;
5137         reply_buf = kmalloc(size, GFP_KERNEL);
5138         if (!reply_buf)
5139                 goto out;
5140
5141         ceph_oid_printf(&oid, "%s", RBD_DIRECTORY);
5142         ret = rbd_obj_method_sync(rbd_dev, &oid, &rbd_dev->header_oloc,
5143                                   "dir_get_name", image_id, image_id_size,
5144                                   reply_buf, size);
5145         if (ret < 0)
5146                 goto out;
5147         p = reply_buf;
5148         end = reply_buf + ret;
5149
5150         image_name = ceph_extract_encoded_string(&p, end, &len, GFP_KERNEL);
5151         if (IS_ERR(image_name))
5152                 image_name = NULL;
5153         else
5154                 dout("%s: name is %s len is %zd\n", __func__, image_name, len);
5155 out:
5156         kfree(reply_buf);
5157         kfree(image_id);
5158
5159         return image_name;
5160 }
5161
5162 static u64 rbd_v1_snap_id_by_name(struct rbd_device *rbd_dev, const char *name)
5163 {
5164         struct ceph_snap_context *snapc = rbd_dev->header.snapc;
5165         const char *snap_name;
5166         u32 which = 0;
5167
5168         /* Skip over names until we find the one we are looking for */
5169
5170         snap_name = rbd_dev->header.snap_names;
5171         while (which < snapc->num_snaps) {
5172                 if (!strcmp(name, snap_name))
5173                         return snapc->snaps[which];
5174                 snap_name += strlen(snap_name) + 1;
5175                 which++;
5176         }
5177         return CEPH_NOSNAP;
5178 }
5179
5180 static u64 rbd_v2_snap_id_by_name(struct rbd_device *rbd_dev, const char *name)
5181 {
5182         struct ceph_snap_context *snapc = rbd_dev->header.snapc;
5183         u32 which;
5184         bool found = false;
5185         u64 snap_id;
5186
5187         for (which = 0; !found && which < snapc->num_snaps; which++) {
5188                 const char *snap_name;
5189
5190                 snap_id = snapc->snaps[which];
5191                 snap_name = rbd_dev_v2_snap_name(rbd_dev, snap_id);
5192                 if (IS_ERR(snap_name)) {
5193                         /* ignore no-longer existing snapshots */
5194                         if (PTR_ERR(snap_name) == -ENOENT)
5195                                 continue;
5196                         else
5197                                 break;
5198                 }
5199                 found = !strcmp(name, snap_name);
5200                 kfree(snap_name);
5201         }
5202         return found ? snap_id : CEPH_NOSNAP;
5203 }
5204
5205 /*
5206  * Assumes name is never RBD_SNAP_HEAD_NAME; returns CEPH_NOSNAP if
5207  * no snapshot by that name is found, or if an error occurs.
5208  */
5209 static u64 rbd_snap_id_by_name(struct rbd_device *rbd_dev, const char *name)
5210 {
5211         if (rbd_dev->image_format == 1)
5212                 return rbd_v1_snap_id_by_name(rbd_dev, name);
5213
5214         return rbd_v2_snap_id_by_name(rbd_dev, name);
5215 }
5216
5217 /*
5218  * An image being mapped will have everything but the snap id.
5219  */
5220 static int rbd_spec_fill_snap_id(struct rbd_device *rbd_dev)
5221 {
5222         struct rbd_spec *spec = rbd_dev->spec;
5223
5224         rbd_assert(spec->pool_id != CEPH_NOPOOL && spec->pool_name);
5225         rbd_assert(spec->image_id && spec->image_name);
5226         rbd_assert(spec->snap_name);
5227
5228         if (strcmp(spec->snap_name, RBD_SNAP_HEAD_NAME)) {
5229                 u64 snap_id;
5230
5231                 snap_id = rbd_snap_id_by_name(rbd_dev, spec->snap_name);
5232                 if (snap_id == CEPH_NOSNAP)
5233                         return -ENOENT;
5234
5235                 spec->snap_id = snap_id;
5236         } else {
5237                 spec->snap_id = CEPH_NOSNAP;
5238         }
5239
5240         return 0;
5241 }
5242
5243 /*
5244  * A parent image will have all ids but none of the names.
5245  *
5246  * All names in an rbd spec are dynamically allocated.  It's OK if we
5247  * can't figure out the name for an image id.
5248  */
5249 static int rbd_spec_fill_names(struct rbd_device *rbd_dev)
5250 {
5251         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
5252         struct rbd_spec *spec = rbd_dev->spec;
5253         const char *pool_name;
5254         const char *image_name;
5255         const char *snap_name;
5256         int ret;
5257
5258         rbd_assert(spec->pool_id != CEPH_NOPOOL);
5259         rbd_assert(spec->image_id);
5260         rbd_assert(spec->snap_id != CEPH_NOSNAP);
5261
5262         /* Get the pool name; we have to make our own copy of this */
5263
5264         pool_name = ceph_pg_pool_name_by_id(osdc->osdmap, spec->pool_id);
5265         if (!pool_name) {
5266                 rbd_warn(rbd_dev, "no pool with id %llu", spec->pool_id);
5267                 return -EIO;
5268         }
5269         pool_name = kstrdup(pool_name, GFP_KERNEL);
5270         if (!pool_name)
5271                 return -ENOMEM;
5272
5273         /* Fetch the image name; tolerate failure here */
5274
5275         image_name = rbd_dev_image_name(rbd_dev);
5276         if (!image_name)
5277                 rbd_warn(rbd_dev, "unable to get image name");
5278
5279         /* Fetch the snapshot name */
5280
5281         snap_name = rbd_snap_name(rbd_dev, spec->snap_id);
5282         if (IS_ERR(snap_name)) {
5283                 ret = PTR_ERR(snap_name);
5284                 goto out_err;
5285         }
5286
5287         spec->pool_name = pool_name;
5288         spec->image_name = image_name;
5289         spec->snap_name = snap_name;
5290
5291         return 0;
5292
5293 out_err:
5294         kfree(image_name);
5295         kfree(pool_name);
5296         return ret;
5297 }
5298
5299 static int rbd_dev_v2_snap_context(struct rbd_device *rbd_dev)
5300 {
5301         size_t size;
5302         int ret;
5303         void *reply_buf;
5304         void *p;
5305         void *end;
5306         u64 seq;
5307         u32 snap_count;
5308         struct ceph_snap_context *snapc;
5309         u32 i;
5310
5311         /*
5312          * We'll need room for the seq value (maximum snapshot id),
5313          * snapshot count, and array of that many snapshot ids.
5314          * For now we have a fixed upper limit on the number we're
5315          * prepared to receive.
5316          */
5317         size = sizeof (__le64) + sizeof (__le32) +
5318                         RBD_MAX_SNAP_COUNT * sizeof (__le64);
5319         reply_buf = kzalloc(size, GFP_KERNEL);
5320         if (!reply_buf)
5321                 return -ENOMEM;
5322
5323         ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
5324                                   &rbd_dev->header_oloc, "get_snapcontext",
5325                                   NULL, 0, reply_buf, size);
5326         dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
5327         if (ret < 0)
5328                 goto out;
5329
5330         p = reply_buf;
5331         end = reply_buf + ret;
5332         ret = -ERANGE;
5333         ceph_decode_64_safe(&p, end, seq, out);
5334         ceph_decode_32_safe(&p, end, snap_count, out);
5335
5336         /*
5337          * Make sure the reported number of snapshot ids wouldn't go
5338          * beyond the end of our buffer.  But before checking that,
5339          * make sure the computed size of the snapshot context we
5340          * allocate is representable in a size_t.
5341          */
5342         if (snap_count > (SIZE_MAX - sizeof (struct ceph_snap_context))
5343                                  / sizeof (u64)) {
5344                 ret = -EINVAL;
5345                 goto out;
5346         }
5347         if (!ceph_has_room(&p, end, snap_count * sizeof (__le64)))
5348                 goto out;
5349         ret = 0;
5350
5351         snapc = ceph_create_snap_context(snap_count, GFP_KERNEL);
5352         if (!snapc) {
5353                 ret = -ENOMEM;
5354                 goto out;
5355         }
5356         snapc->seq = seq;
5357         for (i = 0; i < snap_count; i++)
5358                 snapc->snaps[i] = ceph_decode_64(&p);
5359
5360         ceph_put_snap_context(rbd_dev->header.snapc);
5361         rbd_dev->header.snapc = snapc;
5362
5363         dout("  snap context seq = %llu, snap_count = %u\n",
5364                 (unsigned long long)seq, (unsigned int)snap_count);
5365 out:
5366         kfree(reply_buf);
5367
5368         return ret;
5369 }
5370
5371 static const char *rbd_dev_v2_snap_name(struct rbd_device *rbd_dev,
5372                                         u64 snap_id)
5373 {
5374         size_t size;
5375         void *reply_buf;
5376         __le64 snapid;
5377         int ret;
5378         void *p;
5379         void *end;
5380         char *snap_name;
5381
5382         size = sizeof (__le32) + RBD_MAX_SNAP_NAME_LEN;
5383         reply_buf = kmalloc(size, GFP_KERNEL);
5384         if (!reply_buf)
5385                 return ERR_PTR(-ENOMEM);
5386
5387         snapid = cpu_to_le64(snap_id);
5388         ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
5389                                   &rbd_dev->header_oloc, "get_snapshot_name",
5390                                   &snapid, sizeof(snapid), reply_buf, size);
5391         dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
5392         if (ret < 0) {
5393                 snap_name = ERR_PTR(ret);
5394                 goto out;
5395         }
5396
5397         p = reply_buf;
5398         end = reply_buf + ret;
5399         snap_name = ceph_extract_encoded_string(&p, end, NULL, GFP_KERNEL);
5400         if (IS_ERR(snap_name))
5401                 goto out;
5402
5403         dout("  snap_id 0x%016llx snap_name = %s\n",
5404                 (unsigned long long)snap_id, snap_name);
5405 out:
5406         kfree(reply_buf);
5407
5408         return snap_name;
5409 }
5410
5411 static int rbd_dev_v2_header_info(struct rbd_device *rbd_dev)
5412 {
5413         bool first_time = rbd_dev->header.object_prefix == NULL;
5414         int ret;
5415
5416         ret = rbd_dev_v2_image_size(rbd_dev);
5417         if (ret)
5418                 return ret;
5419
5420         if (first_time) {
5421                 ret = rbd_dev_v2_header_onetime(rbd_dev);
5422                 if (ret)
5423                         return ret;
5424         }
5425
5426         ret = rbd_dev_v2_snap_context(rbd_dev);
5427         if (ret && first_time) {
5428                 kfree(rbd_dev->header.object_prefix);
5429                 rbd_dev->header.object_prefix = NULL;
5430         }
5431
5432         return ret;
5433 }
5434
5435 static int rbd_dev_header_info(struct rbd_device *rbd_dev)
5436 {
5437         rbd_assert(rbd_image_format_valid(rbd_dev->image_format));
5438
5439         if (rbd_dev->image_format == 1)
5440                 return rbd_dev_v1_header_info(rbd_dev);
5441
5442         return rbd_dev_v2_header_info(rbd_dev);
5443 }
5444
5445 /*
5446  * Skips over white space at *buf, and updates *buf to point to the
5447  * first found non-space character (if any). Returns the length of
5448  * the token (string of non-white space characters) found.  Note
5449  * that *buf must be terminated with '\0'.
5450  */
5451 static inline size_t next_token(const char **buf)
5452 {
5453         /*
5454         * These are the characters that produce nonzero for
5455         * isspace() in the "C" and "POSIX" locales.
5456         */
5457         const char *spaces = " \f\n\r\t\v";
5458
5459         *buf += strspn(*buf, spaces);   /* Find start of token */
5460
5461         return strcspn(*buf, spaces);   /* Return token length */
5462 }
5463
5464 /*
5465  * Finds the next token in *buf, dynamically allocates a buffer big
5466  * enough to hold a copy of it, and copies the token into the new
5467  * buffer.  The copy is guaranteed to be terminated with '\0'.  Note
5468  * that a duplicate buffer is created even for a zero-length token.
5469  *
5470  * Returns a pointer to the newly-allocated duplicate, or a null
5471  * pointer if memory for the duplicate was not available.  If
5472  * the lenp argument is a non-null pointer, the length of the token
5473  * (not including the '\0') is returned in *lenp.
5474  *
5475  * If successful, the *buf pointer will be updated to point beyond
5476  * the end of the found token.
5477  *
5478  * Note: uses GFP_KERNEL for allocation.
5479  */
5480 static inline char *dup_token(const char **buf, size_t *lenp)
5481 {
5482         char *dup;
5483         size_t len;
5484
5485         len = next_token(buf);
5486         dup = kmemdup(*buf, len + 1, GFP_KERNEL);
5487         if (!dup)
5488                 return NULL;
5489         *(dup + len) = '\0';
5490         *buf += len;
5491
5492         if (lenp)
5493                 *lenp = len;
5494
5495         return dup;
5496 }
5497
5498 /*
5499  * Parse the options provided for an "rbd add" (i.e., rbd image
5500  * mapping) request.  These arrive via a write to /sys/bus/rbd/add,
5501  * and the data written is passed here via a NUL-terminated buffer.
5502  * Returns 0 if successful or an error code otherwise.
5503  *
5504  * The information extracted from these options is recorded in
5505  * the other parameters which return dynamically-allocated
5506  * structures:
5507  *  ceph_opts
5508  *      The address of a pointer that will refer to a ceph options
5509  *      structure.  Caller must release the returned pointer using
5510  *      ceph_destroy_options() when it is no longer needed.
5511  *  rbd_opts
5512  *      Address of an rbd options pointer.  Fully initialized by
5513  *      this function; caller must release with kfree().
5514  *  spec
5515  *      Address of an rbd image specification pointer.  Fully
5516  *      initialized by this function based on parsed options.
5517  *      Caller must release with rbd_spec_put().
5518  *
5519  * The options passed take this form:
5520  *  <mon_addrs> <options> <pool_name> <image_name> [<snap_id>]
5521  * where:
5522  *  <mon_addrs>
5523  *      A comma-separated list of one or more monitor addresses.
5524  *      A monitor address is an ip address, optionally followed
5525  *      by a port number (separated by a colon).
5526  *        I.e.:  ip1[:port1][,ip2[:port2]...]
5527  *  <options>
5528  *      A comma-separated list of ceph and/or rbd options.
5529  *  <pool_name>
5530  *      The name of the rados pool containing the rbd image.
5531  *  <image_name>
5532  *      The name of the image in that pool to map.
5533  *  <snap_id>
5534  *      An optional snapshot id.  If provided, the mapping will
5535  *      present data from the image at the time that snapshot was
5536  *      created.  The image head is used if no snapshot id is
5537  *      provided.  Snapshot mappings are always read-only.
5538  */
5539 static int rbd_add_parse_args(const char *buf,
5540                                 struct ceph_options **ceph_opts,
5541                                 struct rbd_options **opts,
5542                                 struct rbd_spec **rbd_spec)
5543 {
5544         size_t len;
5545         char *options;
5546         const char *mon_addrs;
5547         char *snap_name;
5548         size_t mon_addrs_size;
5549         struct rbd_spec *spec = NULL;
5550         struct rbd_options *rbd_opts = NULL;
5551         struct ceph_options *copts;
5552         int ret;
5553
5554         /* The first four tokens are required */
5555
5556         len = next_token(&buf);
5557         if (!len) {
5558                 rbd_warn(NULL, "no monitor address(es) provided");
5559                 return -EINVAL;
5560         }
5561         mon_addrs = buf;
5562         mon_addrs_size = len + 1;
5563         buf += len;
5564
5565         ret = -EINVAL;
5566         options = dup_token(&buf, NULL);
5567         if (!options)
5568                 return -ENOMEM;
5569         if (!*options) {
5570                 rbd_warn(NULL, "no options provided");
5571                 goto out_err;
5572         }
5573
5574         spec = rbd_spec_alloc();
5575         if (!spec)
5576                 goto out_mem;
5577
5578         spec->pool_name = dup_token(&buf, NULL);
5579         if (!spec->pool_name)
5580                 goto out_mem;
5581         if (!*spec->pool_name) {
5582                 rbd_warn(NULL, "no pool name provided");
5583                 goto out_err;
5584         }
5585
5586         spec->image_name = dup_token(&buf, NULL);
5587         if (!spec->image_name)
5588                 goto out_mem;
5589         if (!*spec->image_name) {
5590                 rbd_warn(NULL, "no image name provided");
5591                 goto out_err;
5592         }
5593
5594         /*
5595          * Snapshot name is optional; default is to use "-"
5596          * (indicating the head/no snapshot).
5597          */
5598         len = next_token(&buf);
5599         if (!len) {
5600                 buf = RBD_SNAP_HEAD_NAME; /* No snapshot supplied */
5601                 len = sizeof (RBD_SNAP_HEAD_NAME) - 1;
5602         } else if (len > RBD_MAX_SNAP_NAME_LEN) {
5603                 ret = -ENAMETOOLONG;
5604                 goto out_err;
5605         }
5606         snap_name = kmemdup(buf, len + 1, GFP_KERNEL);
5607         if (!snap_name)
5608                 goto out_mem;
5609         *(snap_name + len) = '\0';
5610         spec->snap_name = snap_name;
5611
5612         /* Initialize all rbd options to the defaults */
5613
5614         rbd_opts = kzalloc(sizeof (*rbd_opts), GFP_KERNEL);
5615         if (!rbd_opts)
5616                 goto out_mem;
5617
5618         rbd_opts->read_only = RBD_READ_ONLY_DEFAULT;
5619         rbd_opts->queue_depth = RBD_QUEUE_DEPTH_DEFAULT;
5620         rbd_opts->lock_on_read = RBD_LOCK_ON_READ_DEFAULT;
5621
5622         copts = ceph_parse_options(options, mon_addrs,
5623                                         mon_addrs + mon_addrs_size - 1,
5624                                         parse_rbd_opts_token, rbd_opts);
5625         if (IS_ERR(copts)) {
5626                 ret = PTR_ERR(copts);
5627                 goto out_err;
5628         }
5629         kfree(options);
5630
5631         *ceph_opts = copts;
5632         *opts = rbd_opts;
5633         *rbd_spec = spec;
5634
5635         return 0;
5636 out_mem:
5637         ret = -ENOMEM;
5638 out_err:
5639         kfree(rbd_opts);
5640         rbd_spec_put(spec);
5641         kfree(options);
5642
5643         return ret;
5644 }
5645
5646 /*
5647  * Return pool id (>= 0) or a negative error code.
5648  */
5649 static int rbd_add_get_pool_id(struct rbd_client *rbdc, const char *pool_name)
5650 {
5651         struct ceph_options *opts = rbdc->client->options;
5652         u64 newest_epoch;
5653         int tries = 0;
5654         int ret;
5655
5656 again:
5657         ret = ceph_pg_poolid_by_name(rbdc->client->osdc.osdmap, pool_name);
5658         if (ret == -ENOENT && tries++ < 1) {
5659                 ret = ceph_monc_get_version(&rbdc->client->monc, "osdmap",
5660                                             &newest_epoch);
5661                 if (ret < 0)
5662                         return ret;
5663
5664                 if (rbdc->client->osdc.osdmap->epoch < newest_epoch) {
5665                         ceph_osdc_maybe_request_map(&rbdc->client->osdc);
5666                         (void) ceph_monc_wait_osdmap(&rbdc->client->monc,
5667                                                      newest_epoch,
5668                                                      opts->mount_timeout);
5669                         goto again;
5670                 } else {
5671                         /* the osdmap we have is new enough */
5672                         return -ENOENT;
5673                 }
5674         }
5675
5676         return ret;
5677 }
5678
5679 /*
5680  * An rbd format 2 image has a unique identifier, distinct from the
5681  * name given to it by the user.  Internally, that identifier is
5682  * what's used to specify the names of objects related to the image.
5683  *
5684  * A special "rbd id" object is used to map an rbd image name to its
5685  * id.  If that object doesn't exist, then there is no v2 rbd image
5686  * with the supplied name.
5687  *
5688  * This function will record the given rbd_dev's image_id field if
5689  * it can be determined, and in that case will return 0.  If any
5690  * errors occur a negative errno will be returned and the rbd_dev's
5691  * image_id field will be unchanged (and should be NULL).
5692  */
5693 static int rbd_dev_image_id(struct rbd_device *rbd_dev)
5694 {
5695         int ret;
5696         size_t size;
5697         CEPH_DEFINE_OID_ONSTACK(oid);
5698         void *response;
5699         char *image_id;
5700
5701         /*
5702          * When probing a parent image, the image id is already
5703          * known (and the image name likely is not).  There's no
5704          * need to fetch the image id again in this case.  We
5705          * do still need to set the image format though.
5706          */
5707         if (rbd_dev->spec->image_id) {
5708                 rbd_dev->image_format = *rbd_dev->spec->image_id ? 2 : 1;
5709
5710                 return 0;
5711         }
5712
5713         /*
5714          * First, see if the format 2 image id file exists, and if
5715          * so, get the image's persistent id from it.
5716          */
5717         ret = ceph_oid_aprintf(&oid, GFP_KERNEL, "%s%s", RBD_ID_PREFIX,
5718                                rbd_dev->spec->image_name);
5719         if (ret)
5720                 return ret;
5721
5722         dout("rbd id object name is %s\n", oid.name);
5723
5724         /* Response will be an encoded string, which includes a length */
5725
5726         size = sizeof (__le32) + RBD_IMAGE_ID_LEN_MAX;
5727         response = kzalloc(size, GFP_NOIO);
5728         if (!response) {
5729                 ret = -ENOMEM;
5730                 goto out;
5731         }
5732
5733         /* If it doesn't exist we'll assume it's a format 1 image */
5734
5735         ret = rbd_obj_method_sync(rbd_dev, &oid, &rbd_dev->header_oloc,
5736                                   "get_id", NULL, 0,
5737                                   response, RBD_IMAGE_ID_LEN_MAX);
5738         dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
5739         if (ret == -ENOENT) {
5740                 image_id = kstrdup("", GFP_KERNEL);
5741                 ret = image_id ? 0 : -ENOMEM;
5742                 if (!ret)
5743                         rbd_dev->image_format = 1;
5744         } else if (ret >= 0) {
5745                 void *p = response;
5746
5747                 image_id = ceph_extract_encoded_string(&p, p + ret,
5748                                                 NULL, GFP_NOIO);
5749                 ret = PTR_ERR_OR_ZERO(image_id);
5750                 if (!ret)
5751                         rbd_dev->image_format = 2;
5752         }
5753
5754         if (!ret) {
5755                 rbd_dev->spec->image_id = image_id;
5756                 dout("image_id is %s\n", image_id);
5757         }
5758 out:
5759         kfree(response);
5760         ceph_oid_destroy(&oid);
5761         return ret;
5762 }
5763
5764 /*
5765  * Undo whatever state changes are made by v1 or v2 header info
5766  * call.
5767  */
5768 static void rbd_dev_unprobe(struct rbd_device *rbd_dev)
5769 {
5770         struct rbd_image_header *header;
5771
5772         rbd_dev_parent_put(rbd_dev);
5773
5774         /* Free dynamic fields from the header, then zero it out */
5775
5776         header = &rbd_dev->header;
5777         ceph_put_snap_context(header->snapc);
5778         kfree(header->snap_sizes);
5779         kfree(header->snap_names);
5780         kfree(header->object_prefix);
5781         memset(header, 0, sizeof (*header));
5782 }
5783
5784 static int rbd_dev_v2_header_onetime(struct rbd_device *rbd_dev)
5785 {
5786         int ret;
5787
5788         ret = rbd_dev_v2_object_prefix(rbd_dev);
5789         if (ret)
5790                 goto out_err;
5791
5792         /*
5793          * Get the and check features for the image.  Currently the
5794          * features are assumed to never change.
5795          */
5796         ret = rbd_dev_v2_features(rbd_dev);
5797         if (ret)
5798                 goto out_err;
5799
5800         /* If the image supports fancy striping, get its parameters */
5801
5802         if (rbd_dev->header.features & RBD_FEATURE_STRIPINGV2) {
5803                 ret = rbd_dev_v2_striping_info(rbd_dev);
5804                 if (ret < 0)
5805                         goto out_err;
5806         }
5807
5808         if (rbd_dev->header.features & RBD_FEATURE_DATA_POOL) {
5809                 ret = rbd_dev_v2_data_pool(rbd_dev);
5810                 if (ret)
5811                         goto out_err;
5812         }
5813
5814         rbd_init_layout(rbd_dev);
5815         return 0;
5816
5817 out_err:
5818         rbd_dev->header.features = 0;
5819         kfree(rbd_dev->header.object_prefix);
5820         rbd_dev->header.object_prefix = NULL;
5821         return ret;
5822 }
5823
5824 /*
5825  * @depth is rbd_dev_image_probe() -> rbd_dev_probe_parent() ->
5826  * rbd_dev_image_probe() recursion depth, which means it's also the
5827  * length of the already discovered part of the parent chain.
5828  */
5829 static int rbd_dev_probe_parent(struct rbd_device *rbd_dev, int depth)
5830 {
5831         struct rbd_device *parent = NULL;
5832         int ret;
5833
5834         if (!rbd_dev->parent_spec)
5835                 return 0;
5836
5837         if (++depth > RBD_MAX_PARENT_CHAIN_LEN) {
5838                 pr_info("parent chain is too long (%d)\n", depth);
5839                 ret = -EINVAL;
5840                 goto out_err;
5841         }
5842
5843         parent = __rbd_dev_create(rbd_dev->rbd_client, rbd_dev->parent_spec);
5844         if (!parent) {
5845                 ret = -ENOMEM;
5846                 goto out_err;
5847         }
5848
5849         /*
5850          * Images related by parent/child relationships always share
5851          * rbd_client and spec/parent_spec, so bump their refcounts.
5852          */
5853         __rbd_get_client(rbd_dev->rbd_client);
5854         rbd_spec_get(rbd_dev->parent_spec);
5855
5856         ret = rbd_dev_image_probe(parent, depth);
5857         if (ret < 0)
5858                 goto out_err;
5859
5860         rbd_dev->parent = parent;
5861         atomic_set(&rbd_dev->parent_ref, 1);
5862         return 0;
5863
5864 out_err:
5865         rbd_dev_unparent(rbd_dev);
5866         rbd_dev_destroy(parent);
5867         return ret;
5868 }
5869
5870 /*
5871  * rbd_dev->header_rwsem must be locked for write and will be unlocked
5872  * upon return.
5873  */
5874 static int rbd_dev_device_setup(struct rbd_device *rbd_dev)
5875 {
5876         int ret;
5877
5878         /* Record our major and minor device numbers. */
5879
5880         if (!single_major) {
5881                 ret = register_blkdev(0, rbd_dev->name);
5882                 if (ret < 0)
5883                         goto err_out_unlock;
5884
5885                 rbd_dev->major = ret;
5886                 rbd_dev->minor = 0;
5887         } else {
5888                 rbd_dev->major = rbd_major;
5889                 rbd_dev->minor = rbd_dev_id_to_minor(rbd_dev->dev_id);
5890         }
5891
5892         /* Set up the blkdev mapping. */
5893
5894         ret = rbd_init_disk(rbd_dev);
5895         if (ret)
5896                 goto err_out_blkdev;
5897
5898         ret = rbd_dev_mapping_set(rbd_dev);
5899         if (ret)
5900                 goto err_out_disk;
5901
5902         set_capacity(rbd_dev->disk, rbd_dev->mapping.size / SECTOR_SIZE);
5903         set_disk_ro(rbd_dev->disk, rbd_dev->mapping.read_only);
5904
5905         dev_set_name(&rbd_dev->dev, "%d", rbd_dev->dev_id);
5906         ret = device_add(&rbd_dev->dev);
5907         if (ret)
5908                 goto err_out_mapping;
5909
5910         /* Everything's ready.  Announce the disk to the world. */
5911
5912         set_bit(RBD_DEV_FLAG_EXISTS, &rbd_dev->flags);
5913         up_write(&rbd_dev->header_rwsem);
5914
5915         spin_lock(&rbd_dev_list_lock);
5916         list_add_tail(&rbd_dev->node, &rbd_dev_list);
5917         spin_unlock(&rbd_dev_list_lock);
5918
5919         add_disk(rbd_dev->disk);
5920         pr_info("%s: capacity %llu features 0x%llx\n", rbd_dev->disk->disk_name,
5921                 (unsigned long long)get_capacity(rbd_dev->disk) << SECTOR_SHIFT,
5922                 rbd_dev->header.features);
5923
5924         return ret;
5925
5926 err_out_mapping:
5927         rbd_dev_mapping_clear(rbd_dev);
5928 err_out_disk:
5929         rbd_free_disk(rbd_dev);
5930 err_out_blkdev:
5931         if (!single_major)
5932                 unregister_blkdev(rbd_dev->major, rbd_dev->name);
5933 err_out_unlock:
5934         up_write(&rbd_dev->header_rwsem);
5935         return ret;
5936 }
5937
5938 static int rbd_dev_header_name(struct rbd_device *rbd_dev)
5939 {
5940         struct rbd_spec *spec = rbd_dev->spec;
5941         int ret;
5942
5943         /* Record the header object name for this rbd image. */
5944
5945         rbd_assert(rbd_image_format_valid(rbd_dev->image_format));
5946         if (rbd_dev->image_format == 1)
5947                 ret = ceph_oid_aprintf(&rbd_dev->header_oid, GFP_KERNEL, "%s%s",
5948                                        spec->image_name, RBD_SUFFIX);
5949         else
5950                 ret = ceph_oid_aprintf(&rbd_dev->header_oid, GFP_KERNEL, "%s%s",
5951                                        RBD_HEADER_PREFIX, spec->image_id);
5952
5953         return ret;
5954 }
5955
5956 static void rbd_dev_image_release(struct rbd_device *rbd_dev)
5957 {
5958         rbd_dev_unprobe(rbd_dev);
5959         rbd_dev->image_format = 0;
5960         kfree(rbd_dev->spec->image_id);
5961         rbd_dev->spec->image_id = NULL;
5962
5963         rbd_dev_destroy(rbd_dev);
5964 }
5965
5966 /*
5967  * Probe for the existence of the header object for the given rbd
5968  * device.  If this image is the one being mapped (i.e., not a
5969  * parent), initiate a watch on its header object before using that
5970  * object to get detailed information about the rbd image.
5971  */
5972 static int rbd_dev_image_probe(struct rbd_device *rbd_dev, int depth)
5973 {
5974         int ret;
5975
5976         /*
5977          * Get the id from the image id object.  Unless there's an
5978          * error, rbd_dev->spec->image_id will be filled in with
5979          * a dynamically-allocated string, and rbd_dev->image_format
5980          * will be set to either 1 or 2.
5981          */
5982         ret = rbd_dev_image_id(rbd_dev);
5983         if (ret)
5984                 return ret;
5985
5986         ret = rbd_dev_header_name(rbd_dev);
5987         if (ret)
5988                 goto err_out_format;
5989
5990         if (!depth) {
5991                 ret = rbd_register_watch(rbd_dev);
5992                 if (ret) {
5993                         if (ret == -ENOENT)
5994                                 pr_info("image %s/%s does not exist\n",
5995                                         rbd_dev->spec->pool_name,
5996                                         rbd_dev->spec->image_name);
5997                         goto err_out_format;
5998                 }
5999         }
6000
6001         ret = rbd_dev_header_info(rbd_dev);
6002         if (ret)
6003                 goto err_out_watch;
6004
6005         /*
6006          * If this image is the one being mapped, we have pool name and
6007          * id, image name and id, and snap name - need to fill snap id.
6008          * Otherwise this is a parent image, identified by pool, image
6009          * and snap ids - need to fill in names for those ids.
6010          */
6011         if (!depth)
6012                 ret = rbd_spec_fill_snap_id(rbd_dev);
6013         else
6014                 ret = rbd_spec_fill_names(rbd_dev);
6015         if (ret) {
6016                 if (ret == -ENOENT)
6017                         pr_info("snap %s/%s@%s does not exist\n",
6018                                 rbd_dev->spec->pool_name,
6019                                 rbd_dev->spec->image_name,
6020                                 rbd_dev->spec->snap_name);
6021                 goto err_out_probe;
6022         }
6023
6024         if (rbd_dev->header.features & RBD_FEATURE_LAYERING) {
6025                 ret = rbd_dev_v2_parent_info(rbd_dev);
6026                 if (ret)
6027                         goto err_out_probe;
6028
6029                 /*
6030                  * Need to warn users if this image is the one being
6031                  * mapped and has a parent.
6032                  */
6033                 if (!depth && rbd_dev->parent_spec)
6034                         rbd_warn(rbd_dev,
6035                                  "WARNING: kernel layering is EXPERIMENTAL!");
6036         }
6037
6038         ret = rbd_dev_probe_parent(rbd_dev, depth);
6039         if (ret)
6040                 goto err_out_probe;
6041
6042         dout("discovered format %u image, header name is %s\n",
6043                 rbd_dev->image_format, rbd_dev->header_oid.name);
6044         return 0;
6045
6046 err_out_probe:
6047         rbd_dev_unprobe(rbd_dev);
6048 err_out_watch:
6049         if (!depth)
6050                 rbd_unregister_watch(rbd_dev);
6051 err_out_format:
6052         rbd_dev->image_format = 0;
6053         kfree(rbd_dev->spec->image_id);
6054         rbd_dev->spec->image_id = NULL;
6055         return ret;
6056 }
6057
6058 static ssize_t do_rbd_add(struct bus_type *bus,
6059                           const char *buf,
6060                           size_t count)
6061 {
6062         struct rbd_device *rbd_dev = NULL;
6063         struct ceph_options *ceph_opts = NULL;
6064         struct rbd_options *rbd_opts = NULL;
6065         struct rbd_spec *spec = NULL;
6066         struct rbd_client *rbdc;
6067         bool read_only;
6068         int rc;
6069
6070         if (!try_module_get(THIS_MODULE))
6071                 return -ENODEV;
6072
6073         /* parse add command */
6074         rc = rbd_add_parse_args(buf, &ceph_opts, &rbd_opts, &spec);
6075         if (rc < 0)
6076                 goto out;
6077
6078         rbdc = rbd_get_client(ceph_opts);
6079         if (IS_ERR(rbdc)) {
6080                 rc = PTR_ERR(rbdc);
6081                 goto err_out_args;
6082         }
6083
6084         /* pick the pool */
6085         rc = rbd_add_get_pool_id(rbdc, spec->pool_name);
6086         if (rc < 0) {
6087                 if (rc == -ENOENT)
6088                         pr_info("pool %s does not exist\n", spec->pool_name);
6089                 goto err_out_client;
6090         }
6091         spec->pool_id = (u64)rc;
6092
6093         rbd_dev = rbd_dev_create(rbdc, spec, rbd_opts);
6094         if (!rbd_dev) {
6095                 rc = -ENOMEM;
6096                 goto err_out_client;
6097         }
6098         rbdc = NULL;            /* rbd_dev now owns this */
6099         spec = NULL;            /* rbd_dev now owns this */
6100         rbd_opts = NULL;        /* rbd_dev now owns this */
6101
6102         rbd_dev->config_info = kstrdup(buf, GFP_KERNEL);
6103         if (!rbd_dev->config_info) {
6104                 rc = -ENOMEM;
6105                 goto err_out_rbd_dev;
6106         }
6107
6108         down_write(&rbd_dev->header_rwsem);
6109         rc = rbd_dev_image_probe(rbd_dev, 0);
6110         if (rc < 0) {
6111                 up_write(&rbd_dev->header_rwsem);
6112                 goto err_out_rbd_dev;
6113         }
6114
6115         /* If we are mapping a snapshot it must be marked read-only */
6116
6117         read_only = rbd_dev->opts->read_only;
6118         if (rbd_dev->spec->snap_id != CEPH_NOSNAP)
6119                 read_only = true;
6120         rbd_dev->mapping.read_only = read_only;
6121
6122         rc = rbd_dev_device_setup(rbd_dev);
6123         if (rc) {
6124                 /*
6125                  * rbd_unregister_watch() can't be moved into
6126                  * rbd_dev_image_release() without refactoring, see
6127                  * commit 1f3ef78861ac.
6128                  */
6129                 rbd_unregister_watch(rbd_dev);
6130                 rbd_dev_image_release(rbd_dev);
6131                 goto out;
6132         }
6133
6134         rc = count;
6135 out:
6136         module_put(THIS_MODULE);
6137         return rc;
6138
6139 err_out_rbd_dev:
6140         rbd_dev_destroy(rbd_dev);
6141 err_out_client:
6142         rbd_put_client(rbdc);
6143 err_out_args:
6144         rbd_spec_put(spec);
6145         kfree(rbd_opts);
6146         goto out;
6147 }
6148
6149 static ssize_t rbd_add(struct bus_type *bus,
6150                        const char *buf,
6151                        size_t count)
6152 {
6153         if (single_major)
6154                 return -EINVAL;
6155
6156         return do_rbd_add(bus, buf, count);
6157 }
6158
6159 static ssize_t rbd_add_single_major(struct bus_type *bus,
6160                                     const char *buf,
6161                                     size_t count)
6162 {
6163         return do_rbd_add(bus, buf, count);
6164 }
6165
6166 static void rbd_dev_device_release(struct rbd_device *rbd_dev)
6167 {
6168         rbd_free_disk(rbd_dev);
6169
6170         spin_lock(&rbd_dev_list_lock);
6171         list_del_init(&rbd_dev->node);
6172         spin_unlock(&rbd_dev_list_lock);
6173
6174         clear_bit(RBD_DEV_FLAG_EXISTS, &rbd_dev->flags);
6175         device_del(&rbd_dev->dev);
6176         rbd_dev_mapping_clear(rbd_dev);
6177         if (!single_major)
6178                 unregister_blkdev(rbd_dev->major, rbd_dev->name);
6179 }
6180
6181 static void rbd_dev_remove_parent(struct rbd_device *rbd_dev)
6182 {
6183         while (rbd_dev->parent) {
6184                 struct rbd_device *first = rbd_dev;
6185                 struct rbd_device *second = first->parent;
6186                 struct rbd_device *third;
6187
6188                 /*
6189                  * Follow to the parent with no grandparent and
6190                  * remove it.
6191                  */
6192                 while (second && (third = second->parent)) {
6193                         first = second;
6194                         second = third;
6195                 }
6196                 rbd_assert(second);
6197                 rbd_dev_image_release(second);
6198                 first->parent = NULL;
6199                 first->parent_overlap = 0;
6200
6201                 rbd_assert(first->parent_spec);
6202                 rbd_spec_put(first->parent_spec);
6203                 first->parent_spec = NULL;
6204         }
6205 }
6206
6207 static ssize_t do_rbd_remove(struct bus_type *bus,
6208                              const char *buf,
6209                              size_t count)
6210 {
6211         struct rbd_device *rbd_dev = NULL;
6212         struct list_head *tmp;
6213         int dev_id;
6214         char opt_buf[6];
6215         bool already = false;
6216         bool force = false;
6217         int ret;
6218
6219         dev_id = -1;
6220         opt_buf[0] = '\0';
6221         sscanf(buf, "%d %5s", &dev_id, opt_buf);
6222         if (dev_id < 0) {
6223                 pr_err("dev_id out of range\n");
6224                 return -EINVAL;
6225         }
6226         if (opt_buf[0] != '\0') {
6227                 if (!strcmp(opt_buf, "force")) {
6228                         force = true;
6229                 } else {
6230                         pr_err("bad remove option at '%s'\n", opt_buf);
6231                         return -EINVAL;
6232                 }
6233         }
6234
6235         ret = -ENOENT;
6236         spin_lock(&rbd_dev_list_lock);
6237         list_for_each(tmp, &rbd_dev_list) {
6238                 rbd_dev = list_entry(tmp, struct rbd_device, node);
6239                 if (rbd_dev->dev_id == dev_id) {
6240                         ret = 0;
6241                         break;
6242                 }
6243         }
6244         if (!ret) {
6245                 spin_lock_irq(&rbd_dev->lock);
6246                 if (rbd_dev->open_count && !force)
6247                         ret = -EBUSY;
6248                 else
6249                         already = test_and_set_bit(RBD_DEV_FLAG_REMOVING,
6250                                                         &rbd_dev->flags);
6251                 spin_unlock_irq(&rbd_dev->lock);
6252         }
6253         spin_unlock(&rbd_dev_list_lock);
6254         if (ret < 0 || already)
6255                 return ret;
6256
6257         if (force) {
6258                 /*
6259                  * Prevent new IO from being queued and wait for existing
6260                  * IO to complete/fail.
6261                  */
6262                 blk_mq_freeze_queue(rbd_dev->disk->queue);
6263                 blk_set_queue_dying(rbd_dev->disk->queue);
6264         }
6265
6266         down_write(&rbd_dev->lock_rwsem);
6267         if (__rbd_is_lock_owner(rbd_dev))
6268                 rbd_unlock(rbd_dev);
6269         up_write(&rbd_dev->lock_rwsem);
6270         rbd_unregister_watch(rbd_dev);
6271
6272         /*
6273          * Don't free anything from rbd_dev->disk until after all
6274          * notifies are completely processed. Otherwise
6275          * rbd_bus_del_dev() will race with rbd_watch_cb(), resulting
6276          * in a potential use after free of rbd_dev->disk or rbd_dev.
6277          */
6278         rbd_dev_device_release(rbd_dev);
6279         rbd_dev_image_release(rbd_dev);
6280
6281         return count;
6282 }
6283
6284 static ssize_t rbd_remove(struct bus_type *bus,
6285                           const char *buf,
6286                           size_t count)
6287 {
6288         if (single_major)
6289                 return -EINVAL;
6290
6291         return do_rbd_remove(bus, buf, count);
6292 }
6293
6294 static ssize_t rbd_remove_single_major(struct bus_type *bus,
6295                                        const char *buf,
6296                                        size_t count)
6297 {
6298         return do_rbd_remove(bus, buf, count);
6299 }
6300
6301 /*
6302  * create control files in sysfs
6303  * /sys/bus/rbd/...
6304  */
6305 static int rbd_sysfs_init(void)
6306 {
6307         int ret;
6308
6309         ret = device_register(&rbd_root_dev);
6310         if (ret < 0)
6311                 return ret;
6312
6313         ret = bus_register(&rbd_bus_type);
6314         if (ret < 0)
6315                 device_unregister(&rbd_root_dev);
6316
6317         return ret;
6318 }
6319
6320 static void rbd_sysfs_cleanup(void)
6321 {
6322         bus_unregister(&rbd_bus_type);
6323         device_unregister(&rbd_root_dev);
6324 }
6325
6326 static int rbd_slab_init(void)
6327 {
6328         rbd_assert(!rbd_img_request_cache);
6329         rbd_img_request_cache = KMEM_CACHE(rbd_img_request, 0);
6330         if (!rbd_img_request_cache)
6331                 return -ENOMEM;
6332
6333         rbd_assert(!rbd_obj_request_cache);
6334         rbd_obj_request_cache = KMEM_CACHE(rbd_obj_request, 0);
6335         if (!rbd_obj_request_cache)
6336                 goto out_err;
6337
6338         return 0;
6339
6340 out_err:
6341         kmem_cache_destroy(rbd_img_request_cache);
6342         rbd_img_request_cache = NULL;
6343         return -ENOMEM;
6344 }
6345
6346 static void rbd_slab_exit(void)
6347 {
6348         rbd_assert(rbd_obj_request_cache);
6349         kmem_cache_destroy(rbd_obj_request_cache);
6350         rbd_obj_request_cache = NULL;
6351
6352         rbd_assert(rbd_img_request_cache);
6353         kmem_cache_destroy(rbd_img_request_cache);
6354         rbd_img_request_cache = NULL;
6355 }
6356
6357 static int __init rbd_init(void)
6358 {
6359         int rc;
6360
6361         if (!libceph_compatible(NULL)) {
6362                 rbd_warn(NULL, "libceph incompatibility (quitting)");
6363                 return -EINVAL;
6364         }
6365
6366         rc = rbd_slab_init();
6367         if (rc)
6368                 return rc;
6369
6370         /*
6371          * The number of active work items is limited by the number of
6372          * rbd devices * queue depth, so leave @max_active at default.
6373          */
6374         rbd_wq = alloc_workqueue(RBD_DRV_NAME, WQ_MEM_RECLAIM, 0);
6375         if (!rbd_wq) {
6376                 rc = -ENOMEM;
6377                 goto err_out_slab;
6378         }
6379
6380         if (single_major) {
6381                 rbd_major = register_blkdev(0, RBD_DRV_NAME);
6382                 if (rbd_major < 0) {
6383                         rc = rbd_major;
6384                         goto err_out_wq;
6385                 }
6386         }
6387
6388         rc = rbd_sysfs_init();
6389         if (rc)
6390                 goto err_out_blkdev;
6391
6392         if (single_major)
6393                 pr_info("loaded (major %d)\n", rbd_major);
6394         else
6395                 pr_info("loaded\n");
6396
6397         return 0;
6398
6399 err_out_blkdev:
6400         if (single_major)
6401                 unregister_blkdev(rbd_major, RBD_DRV_NAME);
6402 err_out_wq:
6403         destroy_workqueue(rbd_wq);
6404 err_out_slab:
6405         rbd_slab_exit();
6406         return rc;
6407 }
6408
6409 static void __exit rbd_exit(void)
6410 {
6411         ida_destroy(&rbd_dev_id_ida);
6412         rbd_sysfs_cleanup();
6413         if (single_major)
6414                 unregister_blkdev(rbd_major, RBD_DRV_NAME);
6415         destroy_workqueue(rbd_wq);
6416         rbd_slab_exit();
6417 }
6418
6419 module_init(rbd_init);
6420 module_exit(rbd_exit);
6421
6422 MODULE_AUTHOR("Alex Elder <elder@inktank.com>");
6423 MODULE_AUTHOR("Sage Weil <sage@newdream.net>");
6424 MODULE_AUTHOR("Yehuda Sadeh <yehuda@hq.newdream.net>");
6425 /* following authorship retained from original osdblk.c */
6426 MODULE_AUTHOR("Jeff Garzik <jeff@garzik.org>");
6427
6428 MODULE_DESCRIPTION("RADOS Block Device (RBD) driver");
6429 MODULE_LICENSE("GPL");