fs/nilfs2/the_nilfs.c

   1 /*
   2  * the_nilfs.c - the_nilfs shared structure.
   3  *
   4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  * Written by Ryusuke Konishi <ryusuke@osrg.net>
  21  *
  22  */
  23
  24 #include <linux/buffer_head.h>
  25 #include <linux/slab.h>
  26 #include <linux/blkdev.h>
  27 #include <linux/backing-dev.h>
  28 #include <linux/crc32.h>
  29 #include "nilfs.h"
  30 #include "segment.h"
  31 #include "alloc.h"
  32 #include "cpfile.h"
  33 #include "sufile.h"
  34 #include "dat.h"
  35 #include "segbuf.h"
  36
  37
  38 static int nilfs_valid_sb(struct nilfs_super_block *sbp);
  39
  40 void nilfs_set_last_segment(struct the_nilfs *nilfs,
  41                             sector_t start_blocknr, u64 seq, __u64 cno)
  42 {
  43         spin_lock(&nilfs->ns_last_segment_lock);
  44         nilfs->ns_last_pseg = start_blocknr;
  45         nilfs->ns_last_seq = seq;
  46         nilfs->ns_last_cno = cno;
  47
  48         if (!nilfs_sb_dirty(nilfs)) {
  49                 if (nilfs->ns_prev_seq == nilfs->ns_last_seq)
  50                         goto stay_cursor;
  51
  52                 set_nilfs_sb_dirty(nilfs);
  53         }
  54         nilfs->ns_prev_seq = nilfs->ns_last_seq;
  55
  56  stay_cursor:
  57         spin_unlock(&nilfs->ns_last_segment_lock);
  58 }
  59
  60 /**
  61  * alloc_nilfs - allocate a nilfs object
  62  * @bdev: block device to which the_nilfs is related
  63  *
  64  * Return Value: On success, pointer to the_nilfs is returned.
  65  * On error, NULL is returned.
  66  */
  67 struct the_nilfs *alloc_nilfs(struct block_device *bdev)
  68 {
  69         struct the_nilfs *nilfs;
  70
  71         nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL);
  72         if (!nilfs)
  73                 return NULL;
  74
  75         nilfs->ns_bdev = bdev;
  76         atomic_set(&nilfs->ns_ndirtyblks, 0);
  77         init_rwsem(&nilfs->ns_sem);
  78         INIT_LIST_HEAD(&nilfs->ns_gc_inodes);
  79         spin_lock_init(&nilfs->ns_last_segment_lock);
  80         nilfs->ns_cptree = RB_ROOT;
  81         spin_lock_init(&nilfs->ns_cptree_lock);
  82         init_rwsem(&nilfs->ns_segctor_sem);
  83
  84         return nilfs;
  85 }
  86
  87 /**
  88  * destroy_nilfs - destroy nilfs object
  89  * @nilfs: nilfs object to be released
  90  */
  91 void destroy_nilfs(struct the_nilfs *nilfs)
  92 {
  93         might_sleep();
  94         if (nilfs_init(nilfs)) {
  95                 brelse(nilfs->ns_sbh[0]);
  96                 brelse(nilfs->ns_sbh[1]);
  97         }
  98         kfree(nilfs);
  99 }
 100
 101 static int nilfs_load_super_root(struct the_nilfs *nilfs,
 102                                  struct super_block *sb, sector_t sr_block)
 103 {
 104         struct buffer_head *bh_sr;
 105         struct nilfs_super_root *raw_sr;
 106         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 107         struct nilfs_inode *rawi;
 108         unsigned dat_entry_size, segment_usage_size, checkpoint_size;
 109         unsigned inode_size;
 110         int err;
 111
 112         err = nilfs_read_super_root_block(nilfs, sr_block, &bh_sr, 1);
 113         if (unlikely(err))
 114                 return err;
 115
 116         down_read(&nilfs->ns_sem);
 117         dat_entry_size = le16_to_cpu(sbp[0]->s_dat_entry_size);
 118         checkpoint_size = le16_to_cpu(sbp[0]->s_checkpoint_size);
 119         segment_usage_size = le16_to_cpu(sbp[0]->s_segment_usage_size);
 120         up_read(&nilfs->ns_sem);
 121
 122         inode_size = nilfs->ns_inode_size;
 123
 124         rawi = (void *)bh_sr->b_data + NILFS_SR_DAT_OFFSET(inode_size);
 125         err = nilfs_dat_read(sb, dat_entry_size, rawi, &nilfs->ns_dat);
 126         if (err)
 127                 goto failed;
 128
 129         rawi = (void *)bh_sr->b_data + NILFS_SR_CPFILE_OFFSET(inode_size);
 130         err = nilfs_cpfile_read(sb, checkpoint_size, rawi, &nilfs->ns_cpfile);
 131         if (err)
 132                 goto failed_dat;
 133
 134         rawi = (void *)bh_sr->b_data + NILFS_SR_SUFILE_OFFSET(inode_size);
 135         err = nilfs_sufile_read(sb, segment_usage_size, rawi,
 136                                 &nilfs->ns_sufile);
 137         if (err)
 138                 goto failed_cpfile;
 139
 140         raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
 141         nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime);
 142
 143  failed:
 144         brelse(bh_sr);
 145         return err;
 146
 147  failed_cpfile:
 148         iput(nilfs->ns_cpfile);
 149
 150  failed_dat:
 151         iput(nilfs->ns_dat);
 152         goto failed;
 153 }
 154
 155 static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri)
 156 {
 157         memset(ri, 0, sizeof(*ri));
 158         INIT_LIST_HEAD(&ri->ri_used_segments);
 159 }
 160
 161 static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
 162 {
 163         nilfs_dispose_segment_list(&ri->ri_used_segments);
 164 }
 165
 166 /**
 167  * nilfs_store_log_cursor - load log cursor from a super block
 168  * @nilfs: nilfs object
 169  * @sbp: buffer storing super block to be read
 170  *
 171  * nilfs_store_log_cursor() reads the last position of the log
 172  * containing a super root from a given super block, and initializes
 173  * relevant information on the nilfs object preparatory for log
 174  * scanning and recovery.
 175  */
 176 static int nilfs_store_log_cursor(struct the_nilfs *nilfs,
 177                                   struct nilfs_super_block *sbp)
 178 {
 179         int ret = 0;
 180
 181         nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg);
 182         nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno);
 183         nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq);
 184
 185         nilfs->ns_prev_seq = nilfs->ns_last_seq;
 186         nilfs->ns_seg_seq = nilfs->ns_last_seq;
 187         nilfs->ns_segnum =
 188                 nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg);
 189         nilfs->ns_cno = nilfs->ns_last_cno + 1;
 190         if (nilfs->ns_segnum >= nilfs->ns_nsegments) {
 191                 printk(KERN_ERR "NILFS invalid last segment number.\n");
 192                 ret = -EINVAL;
 193         }
 194         return ret;
 195 }
 196
 197 /**
 198  * load_nilfs - load and recover the nilfs
 199  * @nilfs: the_nilfs structure to be released
 200  * @sbi: nilfs_sb_info used to recover past segment
 201  *
 202  * load_nilfs() searches and load the latest super root,
 203  * attaches the last segment, and does recovery if needed.
 204  * The caller must call this exclusively for simultaneous mounts.
 205  */
 206 int load_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
 207 {
 208         struct nilfs_recovery_info ri;
 209         unsigned int s_flags = sbi->s_super->s_flags;
 210         int really_read_only = bdev_read_only(nilfs->ns_bdev);
 211         int valid_fs = nilfs_valid_fs(nilfs);
 212         int err;
 213
 214         if (!valid_fs) {
 215                 printk(KERN_WARNING "NILFS warning: mounting unchecked fs\n");
 216                 if (s_flags & MS_RDONLY) {
 217                         printk(KERN_INFO "NILFS: INFO: recovery "
 218                                "required for readonly filesystem.\n");
 219                         printk(KERN_INFO "NILFS: write access will "
 220                                "be enabled during recovery.\n");
 221                 }
 222         }
 223
 224         nilfs_init_recovery_info(&ri);
 225
 226         err = nilfs_search_super_root(nilfs, &ri);
 227         if (unlikely(err)) {
 228                 struct nilfs_super_block **sbp = nilfs->ns_sbp;
 229                 int blocksize;
 230
 231                 if (err != -EINVAL)
 232                         goto scan_error;
 233
 234                 if (!nilfs_valid_sb(sbp[1])) {
 235                         printk(KERN_WARNING
 236                                "NILFS warning: unable to fall back to spare"
 237                                "super block\n");
 238                         goto scan_error;
 239                 }
 240                 printk(KERN_INFO
 241                        "NILFS: try rollback from an earlier position\n");
 242
 243                 /*
 244                  * restore super block with its spare and reconfigure
 245                  * relevant states of the nilfs object.
 246                  */
 247                 memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
 248                 nilfs->ns_crc_seed = le32_to_cpu(sbp[0]->s_crc_seed);
 249                 nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
 250
 251                 /* verify consistency between two super blocks */
 252                 blocksize = BLOCK_SIZE << le32_to_cpu(sbp[0]->s_log_block_size);
 253                 if (blocksize != nilfs->ns_blocksize) {
 254                         printk(KERN_WARNING
 255                                "NILFS warning: blocksize differs between "
 256                                "two super blocks (%d != %d)\n",
 257                                blocksize, nilfs->ns_blocksize);
 258                         goto scan_error;
 259                 }
 260
 261                 err = nilfs_store_log_cursor(nilfs, sbp[0]);
 262                 if (err)
 263                         goto scan_error;
 264
 265                 /* drop clean flag to allow roll-forward and recovery */
 266                 nilfs->ns_mount_state &= ~NILFS_VALID_FS;
 267                 valid_fs = 0;
 268
 269                 err = nilfs_search_super_root(nilfs, &ri);
 270                 if (err)
 271                         goto scan_error;
 272         }
 273
 274         err = nilfs_load_super_root(nilfs, sbi->s_super, ri.ri_super_root);
 275         if (unlikely(err)) {
 276                 printk(KERN_ERR "NILFS: error loading super root.\n");
 277                 goto failed;
 278         }
 279
 280         if (valid_fs)
 281                 goto skip_recovery;
 282
 283         if (s_flags & MS_RDONLY) {
 284                 __u64 features;
 285
 286                 if (nilfs_test_opt(sbi, NORECOVERY)) {
 287                         printk(KERN_INFO "NILFS: norecovery option specified. "
 288                                "skipping roll-forward recovery\n");
 289                         goto skip_recovery;
 290                 }
 291                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
 292                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
 293                 if (features) {
 294                         printk(KERN_ERR "NILFS: couldn't proceed with "
 295                                "recovery because of unsupported optional "
 296                                "features (%llx)\n",
 297                                (unsigned long long)features);
 298                         err = -EROFS;
 299                         goto failed_unload;
 300                 }
 301                 if (really_read_only) {
 302                         printk(KERN_ERR "NILFS: write access "
 303                                "unavailable, cannot proceed.\n");
 304                         err = -EROFS;
 305                         goto failed_unload;
 306                 }
 307                 sbi->s_super->s_flags &= ~MS_RDONLY;
 308         } else if (nilfs_test_opt(sbi, NORECOVERY)) {
 309                 printk(KERN_ERR "NILFS: recovery cancelled because norecovery "
 310                        "option was specified for a read/write mount\n");
 311                 err = -EINVAL;
 312                 goto failed_unload;
 313         }
 314
 315         err = nilfs_salvage_orphan_logs(nilfs, sbi, &ri);
 316         if (err)
 317                 goto failed_unload;
 318
 319         down_write(&nilfs->ns_sem);
 320         nilfs->ns_mount_state |= NILFS_VALID_FS; /* set "clean" flag */
 321         err = nilfs_cleanup_super(sbi);
 322         up_write(&nilfs->ns_sem);
 323
 324         if (err) {
 325                 printk(KERN_ERR "NILFS: failed to update super block. "
 326                        "recovery unfinished.\n");
 327                 goto failed_unload;
 328         }
 329         printk(KERN_INFO "NILFS: recovery complete.\n");
 330
 331  skip_recovery:
 332         nilfs_clear_recovery_info(&ri);
 333         sbi->s_super->s_flags = s_flags;
 334         return 0;
 335
 336  scan_error:
 337         printk(KERN_ERR "NILFS: error searching super root.\n");
 338         goto failed;
 339
 340  failed_unload:
 341         iput(nilfs->ns_cpfile);
 342         iput(nilfs->ns_sufile);
 343         iput(nilfs->ns_dat);
 344
 345  failed:
 346         nilfs_clear_recovery_info(&ri);
 347         sbi->s_super->s_flags = s_flags;
 348         return err;
 349 }
 350
 351 static unsigned long long nilfs_max_size(unsigned int blkbits)
 352 {
 353         unsigned int max_bits;
 354         unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */
 355
 356         max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */
 357         if (max_bits < 64)
 358                 res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
 359         return res;
 360 }
 361
 362 static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
 363                                    struct nilfs_super_block *sbp)
 364 {
 365         if (le32_to_cpu(sbp->s_rev_level) < NILFS_MIN_SUPP_REV) {
 366                 printk(KERN_ERR "NILFS: unsupported revision "
 367                        "(superblock rev.=%d.%d, current rev.=%d.%d). "
 368                        "Please check the version of mkfs.nilfs.\n",
 369                        le32_to_cpu(sbp->s_rev_level),
 370                        le16_to_cpu(sbp->s_minor_rev_level),
 371                        NILFS_CURRENT_REV, NILFS_MINOR_REV);
 372                 return -EINVAL;
 373         }
 374         nilfs->ns_sbsize = le16_to_cpu(sbp->s_bytes);
 375         if (nilfs->ns_sbsize > BLOCK_SIZE)
 376                 return -EINVAL;
 377
 378         nilfs->ns_inode_size = le16_to_cpu(sbp->s_inode_size);
 379         nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino);
 380
 381         nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
 382         if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) {
 383                 printk(KERN_ERR "NILFS: too short segment.\n");
 384                 return -EINVAL;
 385         }
 386
 387         nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block);
 388         nilfs->ns_nsegments = le64_to_cpu(sbp->s_nsegments);
 389         nilfs->ns_r_segments_percentage =
 390                 le32_to_cpu(sbp->s_r_segments_percentage);
 391         nilfs->ns_nrsvsegs =
 392                 max_t(unsigned long, NILFS_MIN_NRSVSEGS,
 393                       DIV_ROUND_UP(nilfs->ns_nsegments *
 394                                    nilfs->ns_r_segments_percentage, 100));
 395         nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
 396         return 0;
 397 }
 398
 399 static int nilfs_valid_sb(struct nilfs_super_block *sbp)
 400 {
 401         static unsigned char sum[4];
 402         const int sumoff = offsetof(struct nilfs_super_block, s_sum);
 403         size_t bytes;
 404         u32 crc;
 405
 406         if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC)
 407                 return 0;
 408         bytes = le16_to_cpu(sbp->s_bytes);
 409         if (bytes > BLOCK_SIZE)
 410                 return 0;
 411         crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp,
 412                        sumoff);
 413         crc = crc32_le(crc, sum, 4);
 414         crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4,
 415                        bytes - sumoff - 4);
 416         return crc == le32_to_cpu(sbp->s_sum);
 417 }
 418
 419 static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
 420 {
 421         return offset < ((le64_to_cpu(sbp->s_nsegments) *
 422                           le32_to_cpu(sbp->s_blocks_per_segment)) <<
 423                          (le32_to_cpu(sbp->s_log_block_size) + 10));
 424 }
 425
 426 static void nilfs_release_super_block(struct the_nilfs *nilfs)
 427 {
 428         int i;
 429
 430         for (i = 0; i < 2; i++) {
 431                 if (nilfs->ns_sbp[i]) {
 432                         brelse(nilfs->ns_sbh[i]);
 433                         nilfs->ns_sbh[i] = NULL;
 434                         nilfs->ns_sbp[i] = NULL;
 435                 }
 436         }
 437 }
 438
 439 void nilfs_fall_back_super_block(struct the_nilfs *nilfs)
 440 {
 441         brelse(nilfs->ns_sbh[0]);
 442         nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
 443         nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
 444         nilfs->ns_sbh[1] = NULL;
 445         nilfs->ns_sbp[1] = NULL;
 446 }
 447
 448 void nilfs_swap_super_block(struct the_nilfs *nilfs)
 449 {
 450         struct buffer_head *tsbh = nilfs->ns_sbh[0];
 451         struct nilfs_super_block *tsbp = nilfs->ns_sbp[0];
 452
 453         nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
 454         nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
 455         nilfs->ns_sbh[1] = tsbh;
 456         nilfs->ns_sbp[1] = tsbp;
 457 }
 458
 459 static int nilfs_load_super_block(struct the_nilfs *nilfs,
 460                                   struct super_block *sb, int blocksize,
 461                                   struct nilfs_super_block **sbpp)
 462 {
 463         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 464         struct buffer_head **sbh = nilfs->ns_sbh;
 465         u64 sb2off = NILFS_SB2_OFFSET_BYTES(nilfs->ns_bdev->bd_inode->i_size);
 466         int valid[2], swp = 0;
 467
 468         sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
 469                                         &sbh[0]);
 470         sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]);
 471
 472         if (!sbp[0]) {
 473                 if (!sbp[1]) {
 474                         printk(KERN_ERR "NILFS: unable to read superblock\n");
 475                         return -EIO;
 476                 }
 477                 printk(KERN_WARNING
 478                        "NILFS warning: unable to read primary superblock\n");
 479         } else if (!sbp[1])
 480                 printk(KERN_WARNING
 481                        "NILFS warning: unable to read secondary superblock\n");
 482
 483         /*
 484          * Compare two super blocks and set 1 in swp if the secondary
 485          * super block is valid and newer.  Otherwise, set 0 in swp.
 486          */
 487         valid[0] = nilfs_valid_sb(sbp[0]);
 488         valid[1] = nilfs_valid_sb(sbp[1]);
 489         swp = valid[1] && (!valid[0] ||
 490                            le64_to_cpu(sbp[1]->s_last_cno) >
 491                            le64_to_cpu(sbp[0]->s_last_cno));
 492
 493         if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) {
 494                 brelse(sbh[1]);
 495                 sbh[1] = NULL;
 496                 sbp[1] = NULL;
 497                 swp = 0;
 498         }
 499         if (!valid[swp]) {
 500                 nilfs_release_super_block(nilfs);
 501                 printk(KERN_ERR "NILFS: Can't find nilfs on dev %s.\n",
 502                        sb->s_id);
 503                 return -EINVAL;
 504         }
 505
 506         if (!valid[!swp])
 507                 printk(KERN_WARNING "NILFS warning: broken superblock. "
 508                        "using spare superblock.\n");
 509         if (swp)
 510                 nilfs_swap_super_block(nilfs);
 511
 512         nilfs->ns_sbwcount = 0;
 513         nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
 514         nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq);
 515         *sbpp = sbp[0];
 516         return 0;
 517 }
 518
 519 /**
 520  * init_nilfs - initialize a NILFS instance.
 521  * @nilfs: the_nilfs structure
 522  * @sbi: nilfs_sb_info
 523  * @sb: super block
 524  * @data: mount options
 525  *
 526  * init_nilfs() performs common initialization per block device (e.g.
 527  * reading the super block, getting disk layout information, initializing
 528  * shared fields in the_nilfs).
 529  *
 530  * Return Value: On success, 0 is returned. On error, a negative error
 531  * code is returned.
 532  */
 533 int init_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi, char *data)
 534 {
 535         struct super_block *sb = sbi->s_super;
 536         struct nilfs_super_block *sbp;
 537         int blocksize;
 538         int err;
 539
 540         down_write(&nilfs->ns_sem);
 541
 542         blocksize = sb_min_blocksize(sb, NILFS_MIN_BLOCK_SIZE);
 543         if (!blocksize) {
 544                 printk(KERN_ERR "NILFS: unable to set blocksize\n");
 545                 err = -EINVAL;
 546                 goto out;
 547         }
 548         err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
 549         if (err)
 550                 goto out;
 551
 552         err = nilfs_store_magic_and_option(sb, sbp, data);
 553         if (err)
 554                 goto failed_sbh;
 555
 556         err = nilfs_check_feature_compatibility(sb, sbp);
 557         if (err)
 558                 goto failed_sbh;
 559
 560         blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
 561         if (blocksize < NILFS_MIN_BLOCK_SIZE ||
 562             blocksize > NILFS_MAX_BLOCK_SIZE) {
 563                 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
 564                        "filesystem blocksize %d\n", blocksize);
 565                 err = -EINVAL;
 566                 goto failed_sbh;
 567         }
 568         if (sb->s_blocksize != blocksize) {
 569                 int hw_blocksize = bdev_logical_block_size(sb->s_bdev);
 570
 571                 if (blocksize < hw_blocksize) {
 572                         printk(KERN_ERR
 573                                "NILFS: blocksize %d too small for device "
 574                                "(sector-size = %d).\n",
 575                                blocksize, hw_blocksize);
 576                         err = -EINVAL;
 577                         goto failed_sbh;
 578                 }
 579                 nilfs_release_super_block(nilfs);
 580                 sb_set_blocksize(sb, blocksize);
 581
 582                 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
 583                 if (err)
 584                         goto out;
 585                         /* not failed_sbh; sbh is released automatically
 586                            when reloading fails. */
 587         }
 588         nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
 589         nilfs->ns_blocksize = blocksize;
 590
 591         err = nilfs_store_disk_layout(nilfs, sbp);
 592         if (err)
 593                 goto failed_sbh;
 594
 595         sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
 596
 597         nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
 598
 599         err = nilfs_store_log_cursor(nilfs, sbp);
 600         if (err)
 601                 goto failed_sbh;
 602
 603         set_nilfs_init(nilfs);
 604         err = 0;
 605  out:
 606         up_write(&nilfs->ns_sem);
 607         return err;
 608
 609  failed_sbh:
 610         nilfs_release_super_block(nilfs);
 611         goto out;
 612 }
 613
 614 int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump,
 615                             size_t nsegs)
 616 {
 617         sector_t seg_start, seg_end;
 618         sector_t start = 0, nblocks = 0;
 619         unsigned int sects_per_block;
 620         __u64 *sn;
 621         int ret = 0;
 622
 623         sects_per_block = (1 << nilfs->ns_blocksize_bits) /
 624                 bdev_logical_block_size(nilfs->ns_bdev);
 625         for (sn = segnump; sn < segnump + nsegs; sn++) {
 626                 nilfs_get_segment_range(nilfs, *sn, &seg_start, &seg_end);
 627
 628                 if (!nblocks) {
 629                         start = seg_start;
 630                         nblocks = seg_end - seg_start + 1;
 631                 } else if (start + nblocks == seg_start) {
 632                         nblocks += seg_end - seg_start + 1;
 633                 } else {
 634                         ret = blkdev_issue_discard(nilfs->ns_bdev,
 635                                                    start * sects_per_block,
 636                                                    nblocks * sects_per_block,
 637                                                    GFP_NOFS, 0);
 638                         if (ret < 0)
 639                                 return ret;
 640                         nblocks = 0;
 641                 }
 642         }
 643         if (nblocks)
 644                 ret = blkdev_issue_discard(nilfs->ns_bdev,
 645                                            start * sects_per_block,
 646                                            nblocks * sects_per_block,
 647                                            GFP_NOFS, 0);
 648         return ret;
 649 }
 650
 651 int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
 652 {
 653         unsigned long ncleansegs;
 654
 655         down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
 656         ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
 657         up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
 658         *nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment;
 659         return 0;
 660 }
 661
 662 int nilfs_near_disk_full(struct the_nilfs *nilfs)
 663 {
 664         unsigned long ncleansegs, nincsegs;
 665
 666         ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
 667         nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
 668                 nilfs->ns_blocks_per_segment + 1;
 669
 670         return ncleansegs <= nilfs->ns_nrsvsegs + nincsegs;
 671 }
 672
 673 struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno)
 674 {
 675         struct rb_node *n;
 676         struct nilfs_root *root;
 677
 678         spin_lock(&nilfs->ns_cptree_lock);
 679         n = nilfs->ns_cptree.rb_node;
 680         while (n) {
 681                 root = rb_entry(n, struct nilfs_root, rb_node);
 682
 683                 if (cno < root->cno) {
 684                         n = n->rb_left;
 685                 } else if (cno > root->cno) {
 686                         n = n->rb_right;
 687                 } else {
 688                         atomic_inc(&root->count);
 689                         spin_unlock(&nilfs->ns_cptree_lock);
 690                         return root;
 691                 }
 692         }
 693         spin_unlock(&nilfs->ns_cptree_lock);
 694
 695         return NULL;
 696 }
 697
 698 struct nilfs_root *
 699 nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno)
 700 {
 701         struct rb_node **p, *parent;
 702         struct nilfs_root *root, *new;
 703
 704         root = nilfs_lookup_root(nilfs, cno);
 705         if (root)
 706                 return root;
 707
 708         new = kmalloc(sizeof(*root), GFP_KERNEL);
 709         if (!new)
 710                 return NULL;
 711
 712         spin_lock(&nilfs->ns_cptree_lock);
 713
 714         p = &nilfs->ns_cptree.rb_node;
 715         parent = NULL;
 716
 717         while (*p) {
 718                 parent = *p;
 719                 root = rb_entry(parent, struct nilfs_root, rb_node);
 720
 721                 if (cno < root->cno) {
 722                         p = &(*p)->rb_left;
 723                 } else if (cno > root->cno) {
 724                         p = &(*p)->rb_right;
 725                 } else {
 726                         atomic_inc(&root->count);
 727                         spin_unlock(&nilfs->ns_cptree_lock);
 728                         kfree(new);
 729                         return root;
 730                 }
 731         }
 732
 733         new->cno = cno;
 734         new->ifile = NULL;
 735         new->nilfs = nilfs;
 736         atomic_set(&new->count, 1);
 737         atomic_set(&new->inodes_count, 0);
 738         atomic_set(&new->blocks_count, 0);
 739
 740         rb_link_node(&new->rb_node, parent, p);
 741         rb_insert_color(&new->rb_node, &nilfs->ns_cptree);
 742
 743         spin_unlock(&nilfs->ns_cptree_lock);
 744
 745         return new;
 746 }
 747
 748 void nilfs_put_root(struct nilfs_root *root)
 749 {
 750         if (atomic_dec_and_test(&root->count)) {
 751                 struct the_nilfs *nilfs = root->nilfs;
 752
 753                 spin_lock(&nilfs->ns_cptree_lock);
 754                 rb_erase(&root->rb_node, &nilfs->ns_cptree);
 755                 spin_unlock(&nilfs->ns_cptree_lock);
 756                 if (root->ifile)
 757                         iput(root->ifile);
 758
 759                 kfree(root);
 760         }
 761 }