fs/nilfs2/super.c

   1 /*
   2  * super.c - NILFS module and super block management.
   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  *  linux/fs/ext2/super.c
  24  *
  25  * Copyright (C) 1992, 1993, 1994, 1995
  26  * Remy Card (card@masi.ibp.fr)
  27  * Laboratoire MASI - Institut Blaise Pascal
  28  * Universite Pierre et Marie Curie (Paris VI)
  29  *
  30  *  from
  31  *
  32  *  linux/fs/minix/inode.c
  33  *
  34  *  Copyright (C) 1991, 1992  Linus Torvalds
  35  *
  36  *  Big-endian to little-endian byte-swapping/bitmaps by
  37  *        David S. Miller (davem@caip.rutgers.edu), 1995
  38  */
  39
  40 #include <linux/module.h>
  41 #include <linux/string.h>
  42 #include <linux/slab.h>
  43 #include <linux/init.h>
  44 #include <linux/blkdev.h>
  45 #include <linux/parser.h>
  46 #include <linux/random.h>
  47 #include <linux/crc32.h>
  48 #include <linux/vfs.h>
  49 #include <linux/writeback.h>
  50 #include <linux/kobject.h>
  51 #include <linux/seq_file.h>
  52 #include <linux/mount.h>
  53 #include "nilfs.h"
  54 #include "export.h"
  55 #include "mdt.h"
  56 #include "alloc.h"
  57 #include "btree.h"
  58 #include "btnode.h"
  59 #include "page.h"
  60 #include "cpfile.h"
  61 #include "ifile.h"
  62 #include "dat.h"
  63 #include "segment.h"
  64 #include "segbuf.h"
  65
  66 MODULE_AUTHOR("NTT Corp.");
  67 MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
  68                    "(NILFS)");
  69 MODULE_LICENSE("GPL");
  70
  71 static struct kmem_cache *nilfs_inode_cachep;
  72 struct kmem_cache *nilfs_transaction_cachep;
  73 struct kmem_cache *nilfs_segbuf_cachep;
  74 struct kmem_cache *nilfs_btree_path_cache;
  75
  76 static int nilfs_setup_super(struct nilfs_sb_info *sbi, int is_mount);
  77 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
  78
  79 static void nilfs_set_error(struct nilfs_sb_info *sbi)
  80 {
  81         struct the_nilfs *nilfs = sbi->s_nilfs;
  82         struct nilfs_super_block **sbp;
  83
  84         down_write(&nilfs->ns_sem);
  85         if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
  86                 nilfs->ns_mount_state |= NILFS_ERROR_FS;
  87                 sbp = nilfs_prepare_super(sbi, 0);
  88                 if (likely(sbp)) {
  89                         sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  90                         if (sbp[1])
  91                                 sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  92                         nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
  93                 }
  94         }
  95         up_write(&nilfs->ns_sem);
  96 }
  97
  98 /**
  99  * nilfs_error() - report failure condition on a filesystem
 100  *
 101  * nilfs_error() sets an ERROR_FS flag on the superblock as well as
 102  * reporting an error message.  It should be called when NILFS detects
 103  * incoherences or defects of meta data on disk.  As for sustainable
 104  * errors such as a single-shot I/O error, nilfs_warning() or the printk()
 105  * function should be used instead.
 106  *
 107  * The segment constructor must not call this function because it can
 108  * kill itself.
 109  */
 110 void nilfs_error(struct super_block *sb, const char *function,
 111                  const char *fmt, ...)
 112 {
 113         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 114         va_list args;
 115
 116         va_start(args, fmt);
 117         printk(KERN_CRIT "NILFS error (device %s): %s: ", sb->s_id, function);
 118         vprintk(fmt, args);
 119         printk("\n");
 120         va_end(args);
 121
 122         if (!(sb->s_flags & MS_RDONLY)) {
 123                 nilfs_set_error(sbi);
 124
 125                 if (nilfs_test_opt(sbi, ERRORS_RO)) {
 126                         printk(KERN_CRIT "Remounting filesystem read-only\n");
 127                         sb->s_flags |= MS_RDONLY;
 128                 }
 129         }
 130
 131         if (nilfs_test_opt(sbi, ERRORS_PANIC))
 132                 panic("NILFS (device %s): panic forced after error\n",
 133                       sb->s_id);
 134 }
 135
 136 void nilfs_warning(struct super_block *sb, const char *function,
 137                    const char *fmt, ...)
 138 {
 139         va_list args;
 140
 141         va_start(args, fmt);
 142         printk(KERN_WARNING "NILFS warning (device %s): %s: ",
 143                sb->s_id, function);
 144         vprintk(fmt, args);
 145         printk("\n");
 146         va_end(args);
 147 }
 148
 149
 150 struct inode *nilfs_alloc_inode(struct super_block *sb)
 151 {
 152         struct nilfs_inode_info *ii;
 153
 154         ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
 155         if (!ii)
 156                 return NULL;
 157         ii->i_bh = NULL;
 158         ii->i_state = 0;
 159         ii->i_cno = 0;
 160         ii->vfs_inode.i_version = 1;
 161         nilfs_btnode_cache_init(&ii->i_btnode_cache, sb->s_bdi);
 162         return &ii->vfs_inode;
 163 }
 164
 165 void nilfs_destroy_inode(struct inode *inode)
 166 {
 167         struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
 168
 169         if (mdi) {
 170                 kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
 171                 kfree(mdi);
 172         }
 173         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 174 }
 175
 176 static int nilfs_sync_super(struct nilfs_sb_info *sbi, int flag)
 177 {
 178         struct the_nilfs *nilfs = sbi->s_nilfs;
 179         int err;
 180
 181  retry:
 182         set_buffer_dirty(nilfs->ns_sbh[0]);
 183         if (nilfs_test_opt(sbi, BARRIER)) {
 184                 err = __sync_dirty_buffer(nilfs->ns_sbh[0],
 185                                           WRITE_SYNC | WRITE_FLUSH_FUA);
 186         } else {
 187                 err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 188         }
 189
 190         if (unlikely(err)) {
 191                 printk(KERN_ERR
 192                        "NILFS: unable to write superblock (err=%d)\n", err);
 193                 if (err == -EIO && nilfs->ns_sbh[1]) {
 194                         /*
 195                          * sbp[0] points to newer log than sbp[1],
 196                          * so copy sbp[0] to sbp[1] to take over sbp[0].
 197                          */
 198                         memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
 199                                nilfs->ns_sbsize);
 200                         nilfs_fall_back_super_block(nilfs);
 201                         goto retry;
 202                 }
 203         } else {
 204                 struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 205
 206                 nilfs->ns_sbwcount++;
 207
 208                 /*
 209                  * The latest segment becomes trailable from the position
 210                  * written in superblock.
 211                  */
 212                 clear_nilfs_discontinued(nilfs);
 213
 214                 /* update GC protection for recent segments */
 215                 if (nilfs->ns_sbh[1]) {
 216                         if (flag == NILFS_SB_COMMIT_ALL) {
 217                                 set_buffer_dirty(nilfs->ns_sbh[1]);
 218                                 if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
 219                                         goto out;
 220                         }
 221                         if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
 222                             le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
 223                                 sbp = nilfs->ns_sbp[1];
 224                 }
 225
 226                 spin_lock(&nilfs->ns_last_segment_lock);
 227                 nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
 228                 spin_unlock(&nilfs->ns_last_segment_lock);
 229         }
 230  out:
 231         return err;
 232 }
 233
 234 void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
 235                           struct the_nilfs *nilfs)
 236 {
 237         sector_t nfreeblocks;
 238
 239         /* nilfs->ns_sem must be locked by the caller. */
 240         nilfs_count_free_blocks(nilfs, &nfreeblocks);
 241         sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
 242
 243         spin_lock(&nilfs->ns_last_segment_lock);
 244         sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
 245         sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
 246         sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
 247         spin_unlock(&nilfs->ns_last_segment_lock);
 248 }
 249
 250 struct nilfs_super_block **nilfs_prepare_super(struct nilfs_sb_info *sbi,
 251                                                int flip)
 252 {
 253         struct the_nilfs *nilfs = sbi->s_nilfs;
 254         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 255
 256         /* nilfs->ns_sem must be locked by the caller. */
 257         if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 258                 if (sbp[1] &&
 259                     sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
 260                         memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
 261                 } else {
 262                         printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
 263                                sbi->s_super->s_id);
 264                         return NULL;
 265                 }
 266         } else if (sbp[1] &&
 267                    sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 268                         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 269         }
 270
 271         if (flip && sbp[1])
 272                 nilfs_swap_super_block(nilfs);
 273
 274         return sbp;
 275 }
 276
 277 int nilfs_commit_super(struct nilfs_sb_info *sbi, int flag)
 278 {
 279         struct the_nilfs *nilfs = sbi->s_nilfs;
 280         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 281         time_t t;
 282
 283         /* nilfs->ns_sem must be locked by the caller. */
 284         t = get_seconds();
 285         nilfs->ns_sbwtime = t;
 286         sbp[0]->s_wtime = cpu_to_le64(t);
 287         sbp[0]->s_sum = 0;
 288         sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 289                                              (unsigned char *)sbp[0],
 290                                              nilfs->ns_sbsize));
 291         if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
 292                 sbp[1]->s_wtime = sbp[0]->s_wtime;
 293                 sbp[1]->s_sum = 0;
 294                 sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 295                                             (unsigned char *)sbp[1],
 296                                             nilfs->ns_sbsize));
 297         }
 298         clear_nilfs_sb_dirty(nilfs);
 299         return nilfs_sync_super(sbi, flag);
 300 }
 301
 302 /**
 303  * nilfs_cleanup_super() - write filesystem state for cleanup
 304  * @sbi: nilfs_sb_info to be unmounted or degraded to read-only
 305  *
 306  * This function restores state flags in the on-disk super block.
 307  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
 308  * filesystem was not clean previously.
 309  */
 310 int nilfs_cleanup_super(struct nilfs_sb_info *sbi)
 311 {
 312         struct nilfs_super_block **sbp;
 313         int flag = NILFS_SB_COMMIT;
 314         int ret = -EIO;
 315
 316         sbp = nilfs_prepare_super(sbi, 0);
 317         if (sbp) {
 318                 sbp[0]->s_state = cpu_to_le16(sbi->s_nilfs->ns_mount_state);
 319                 nilfs_set_log_cursor(sbp[0], sbi->s_nilfs);
 320                 if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
 321                         /*
 322                          * make the "clean" flag also to the opposite
 323                          * super block if both super blocks point to
 324                          * the same checkpoint.
 325                          */
 326                         sbp[1]->s_state = sbp[0]->s_state;
 327                         flag = NILFS_SB_COMMIT_ALL;
 328                 }
 329                 ret = nilfs_commit_super(sbi, flag);
 330         }
 331         return ret;
 332 }
 333
 334 static void nilfs_put_super(struct super_block *sb)
 335 {
 336         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 337         struct the_nilfs *nilfs = sbi->s_nilfs;
 338
 339         nilfs_detach_segment_constructor(sbi);
 340
 341         if (!(sb->s_flags & MS_RDONLY)) {
 342                 down_write(&nilfs->ns_sem);
 343                 nilfs_cleanup_super(sbi);
 344                 up_write(&nilfs->ns_sem);
 345         }
 346
 347         iput(nilfs->ns_sufile);
 348         iput(nilfs->ns_cpfile);
 349         iput(nilfs->ns_dat);
 350
 351         destroy_nilfs(nilfs);
 352         sbi->s_super = NULL;
 353         sb->s_fs_info = NULL;
 354         kfree(sbi);
 355 }
 356
 357 static int nilfs_sync_fs(struct super_block *sb, int wait)
 358 {
 359         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 360         struct the_nilfs *nilfs = sbi->s_nilfs;
 361         struct nilfs_super_block **sbp;
 362         int err = 0;
 363
 364         /* This function is called when super block should be written back */
 365         if (wait)
 366                 err = nilfs_construct_segment(sb);
 367
 368         down_write(&nilfs->ns_sem);
 369         if (nilfs_sb_dirty(nilfs)) {
 370                 sbp = nilfs_prepare_super(sbi, nilfs_sb_will_flip(nilfs));
 371                 if (likely(sbp)) {
 372                         nilfs_set_log_cursor(sbp[0], nilfs);
 373                         nilfs_commit_super(sbi, NILFS_SB_COMMIT);
 374                 }
 375         }
 376         up_write(&nilfs->ns_sem);
 377
 378         return err;
 379 }
 380
 381 int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno, int curr_mnt,
 382                             struct nilfs_root **rootp)
 383 {
 384         struct the_nilfs *nilfs = sbi->s_nilfs;
 385         struct nilfs_root *root;
 386         struct nilfs_checkpoint *raw_cp;
 387         struct buffer_head *bh_cp;
 388         int err = -ENOMEM;
 389
 390         root = nilfs_find_or_create_root(
 391                 nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
 392         if (!root)
 393                 return err;
 394
 395         if (root->ifile)
 396                 goto reuse; /* already attached checkpoint */
 397
 398         down_read(&nilfs->ns_segctor_sem);
 399         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 400                                           &bh_cp);
 401         up_read(&nilfs->ns_segctor_sem);
 402         if (unlikely(err)) {
 403                 if (err == -ENOENT || err == -EINVAL) {
 404                         printk(KERN_ERR
 405                                "NILFS: Invalid checkpoint "
 406                                "(checkpoint number=%llu)\n",
 407                                (unsigned long long)cno);
 408                         err = -EINVAL;
 409                 }
 410                 goto failed;
 411         }
 412
 413         err = nilfs_ifile_read(sbi->s_super, root, nilfs->ns_inode_size,
 414                                &raw_cp->cp_ifile_inode, &root->ifile);
 415         if (err)
 416                 goto failed_bh;
 417
 418         atomic_set(&root->inodes_count, le64_to_cpu(raw_cp->cp_inodes_count));
 419         atomic_set(&root->blocks_count, le64_to_cpu(raw_cp->cp_blocks_count));
 420
 421         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 422
 423  reuse:
 424         *rootp = root;
 425         return 0;
 426
 427  failed_bh:
 428         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 429  failed:
 430         nilfs_put_root(root);
 431
 432         return err;
 433 }
 434
 435 static int nilfs_freeze(struct super_block *sb)
 436 {
 437         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 438         struct the_nilfs *nilfs = sbi->s_nilfs;
 439         int err;
 440
 441         if (sb->s_flags & MS_RDONLY)
 442                 return 0;
 443
 444         /* Mark super block clean */
 445         down_write(&nilfs->ns_sem);
 446         err = nilfs_cleanup_super(sbi);
 447         up_write(&nilfs->ns_sem);
 448         return err;
 449 }
 450
 451 static int nilfs_unfreeze(struct super_block *sb)
 452 {
 453         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 454         struct the_nilfs *nilfs = sbi->s_nilfs;
 455
 456         if (sb->s_flags & MS_RDONLY)
 457                 return 0;
 458
 459         down_write(&nilfs->ns_sem);
 460         nilfs_setup_super(sbi, false);
 461         up_write(&nilfs->ns_sem);
 462         return 0;
 463 }
 464
 465 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 466 {
 467         struct super_block *sb = dentry->d_sb;
 468         struct nilfs_root *root = NILFS_I(dentry->d_inode)->i_root;
 469         struct the_nilfs *nilfs = root->nilfs;
 470         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 471         unsigned long long blocks;
 472         unsigned long overhead;
 473         unsigned long nrsvblocks;
 474         sector_t nfreeblocks;
 475         int err;
 476
 477         /*
 478          * Compute all of the segment blocks
 479          *
 480          * The blocks before first segment and after last segment
 481          * are excluded.
 482          */
 483         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 484                 - nilfs->ns_first_data_block;
 485         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 486
 487         /*
 488          * Compute the overhead
 489          *
 490          * When distributing meta data blocks outside segment structure,
 491          * We must count them as the overhead.
 492          */
 493         overhead = 0;
 494
 495         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 496         if (unlikely(err))
 497                 return err;
 498
 499         buf->f_type = NILFS_SUPER_MAGIC;
 500         buf->f_bsize = sb->s_blocksize;
 501         buf->f_blocks = blocks - overhead;
 502         buf->f_bfree = nfreeblocks;
 503         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 504                 (buf->f_bfree - nrsvblocks) : 0;
 505         buf->f_files = atomic_read(&root->inodes_count);
 506         buf->f_ffree = 0; /* nilfs_count_free_inodes(sb); */
 507         buf->f_namelen = NILFS_NAME_LEN;
 508         buf->f_fsid.val[0] = (u32)id;
 509         buf->f_fsid.val[1] = (u32)(id >> 32);
 510
 511         return 0;
 512 }
 513
 514 static int nilfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 515 {
 516         struct super_block *sb = vfs->mnt_sb;
 517         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 518         struct nilfs_root *root = NILFS_I(vfs->mnt_root->d_inode)->i_root;
 519
 520         if (!nilfs_test_opt(sbi, BARRIER))
 521                 seq_puts(seq, ",nobarrier");
 522         if (root->cno != NILFS_CPTREE_CURRENT_CNO)
 523                 seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
 524         if (nilfs_test_opt(sbi, ERRORS_PANIC))
 525                 seq_puts(seq, ",errors=panic");
 526         if (nilfs_test_opt(sbi, ERRORS_CONT))
 527                 seq_puts(seq, ",errors=continue");
 528         if (nilfs_test_opt(sbi, STRICT_ORDER))
 529                 seq_puts(seq, ",order=strict");
 530         if (nilfs_test_opt(sbi, NORECOVERY))
 531                 seq_puts(seq, ",norecovery");
 532         if (nilfs_test_opt(sbi, DISCARD))
 533                 seq_puts(seq, ",discard");
 534
 535         return 0;
 536 }
 537
 538 static const struct super_operations nilfs_sops = {
 539         .alloc_inode    = nilfs_alloc_inode,
 540         .destroy_inode  = nilfs_destroy_inode,
 541         .dirty_inode    = nilfs_dirty_inode,
 542         /* .write_inode    = nilfs_write_inode, */
 543         /* .put_inode      = nilfs_put_inode, */
 544         /* .drop_inode    = nilfs_drop_inode, */
 545         .evict_inode    = nilfs_evict_inode,
 546         .put_super      = nilfs_put_super,
 547         /* .write_super    = nilfs_write_super, */
 548         .sync_fs        = nilfs_sync_fs,
 549         .freeze_fs      = nilfs_freeze,
 550         .unfreeze_fs    = nilfs_unfreeze,
 551         /* .write_super_lockfs */
 552         /* .unlockfs */
 553         .statfs         = nilfs_statfs,
 554         .remount_fs     = nilfs_remount,
 555         /* .umount_begin */
 556         .show_options = nilfs_show_options
 557 };
 558
 559 enum {
 560         Opt_err_cont, Opt_err_panic, Opt_err_ro,
 561         Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
 562         Opt_discard, Opt_nodiscard, Opt_err,
 563 };
 564
 565 static match_table_t tokens = {
 566         {Opt_err_cont, "errors=continue"},
 567         {Opt_err_panic, "errors=panic"},
 568         {Opt_err_ro, "errors=remount-ro"},
 569         {Opt_barrier, "barrier"},
 570         {Opt_nobarrier, "nobarrier"},
 571         {Opt_snapshot, "cp=%u"},
 572         {Opt_order, "order=%s"},
 573         {Opt_norecovery, "norecovery"},
 574         {Opt_discard, "discard"},
 575         {Opt_nodiscard, "nodiscard"},
 576         {Opt_err, NULL}
 577 };
 578
 579 static int parse_options(char *options, struct super_block *sb, int is_remount)
 580 {
 581         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 582         char *p;
 583         substring_t args[MAX_OPT_ARGS];
 584
 585         if (!options)
 586                 return 1;
 587
 588         while ((p = strsep(&options, ",")) != NULL) {
 589                 int token;
 590                 if (!*p)
 591                         continue;
 592
 593                 token = match_token(p, tokens, args);
 594                 switch (token) {
 595                 case Opt_barrier:
 596                         nilfs_set_opt(sbi, BARRIER);
 597                         break;
 598                 case Opt_nobarrier:
 599                         nilfs_clear_opt(sbi, BARRIER);
 600                         break;
 601                 case Opt_order:
 602                         if (strcmp(args[0].from, "relaxed") == 0)
 603                                 /* Ordered data semantics */
 604                                 nilfs_clear_opt(sbi, STRICT_ORDER);
 605                         else if (strcmp(args[0].from, "strict") == 0)
 606                                 /* Strict in-order semantics */
 607                                 nilfs_set_opt(sbi, STRICT_ORDER);
 608                         else
 609                                 return 0;
 610                         break;
 611                 case Opt_err_panic:
 612                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_PANIC);
 613                         break;
 614                 case Opt_err_ro:
 615                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_RO);
 616                         break;
 617                 case Opt_err_cont:
 618                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_CONT);
 619                         break;
 620                 case Opt_snapshot:
 621                         if (is_remount) {
 622                                 printk(KERN_ERR
 623                                        "NILFS: \"%s\" option is invalid "
 624                                        "for remount.\n", p);
 625                                 return 0;
 626                         }
 627                         break;
 628                 case Opt_norecovery:
 629                         nilfs_set_opt(sbi, NORECOVERY);
 630                         break;
 631                 case Opt_discard:
 632                         nilfs_set_opt(sbi, DISCARD);
 633                         break;
 634                 case Opt_nodiscard:
 635                         nilfs_clear_opt(sbi, DISCARD);
 636                         break;
 637                 default:
 638                         printk(KERN_ERR
 639                                "NILFS: Unrecognized mount option \"%s\"\n", p);
 640                         return 0;
 641                 }
 642         }
 643         return 1;
 644 }
 645
 646 static inline void
 647 nilfs_set_default_options(struct nilfs_sb_info *sbi,
 648                           struct nilfs_super_block *sbp)
 649 {
 650         sbi->s_mount_opt =
 651                 NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
 652 }
 653
 654 static int nilfs_setup_super(struct nilfs_sb_info *sbi, int is_mount)
 655 {
 656         struct the_nilfs *nilfs = sbi->s_nilfs;
 657         struct nilfs_super_block **sbp;
 658         int max_mnt_count;
 659         int mnt_count;
 660
 661         /* nilfs->ns_sem must be locked by the caller. */
 662         sbp = nilfs_prepare_super(sbi, 0);
 663         if (!sbp)
 664                 return -EIO;
 665
 666         if (!is_mount)
 667                 goto skip_mount_setup;
 668
 669         max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
 670         mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
 671
 672         if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 673                 printk(KERN_WARNING
 674                        "NILFS warning: mounting fs with errors\n");
 675 #if 0
 676         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 677                 printk(KERN_WARNING
 678                        "NILFS warning: maximal mount count reached\n");
 679 #endif
 680         }
 681         if (!max_mnt_count)
 682                 sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 683
 684         sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
 685         sbp[0]->s_mtime = cpu_to_le64(get_seconds());
 686
 687 skip_mount_setup:
 688         sbp[0]->s_state =
 689                 cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
 690         /* synchronize sbp[1] with sbp[0] */
 691         if (sbp[1])
 692                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 693         return nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
 694 }
 695
 696 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 697                                                  u64 pos, int blocksize,
 698                                                  struct buffer_head **pbh)
 699 {
 700         unsigned long long sb_index = pos;
 701         unsigned long offset;
 702
 703         offset = do_div(sb_index, blocksize);
 704         *pbh = sb_bread(sb, sb_index);
 705         if (!*pbh)
 706                 return NULL;
 707         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 708 }
 709
 710 int nilfs_store_magic_and_option(struct super_block *sb,
 711                                  struct nilfs_super_block *sbp,
 712                                  char *data)
 713 {
 714         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 715
 716         sb->s_magic = le16_to_cpu(sbp->s_magic);
 717
 718         /* FS independent flags */
 719 #ifdef NILFS_ATIME_DISABLE
 720         sb->s_flags |= MS_NOATIME;
 721 #endif
 722
 723         nilfs_set_default_options(sbi, sbp);
 724
 725         sbi->s_resuid = le16_to_cpu(sbp->s_def_resuid);
 726         sbi->s_resgid = le16_to_cpu(sbp->s_def_resgid);
 727         sbi->s_interval = le32_to_cpu(sbp->s_c_interval);
 728         sbi->s_watermark = le32_to_cpu(sbp->s_c_block_max);
 729
 730         return !parse_options(data, sb, 0) ? -EINVAL : 0 ;
 731 }
 732
 733 int nilfs_check_feature_compatibility(struct super_block *sb,
 734                                       struct nilfs_super_block *sbp)
 735 {
 736         __u64 features;
 737
 738         features = le64_to_cpu(sbp->s_feature_incompat) &
 739                 ~NILFS_FEATURE_INCOMPAT_SUPP;
 740         if (features) {
 741                 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
 742                        "optional features (%llx)\n",
 743                        (unsigned long long)features);
 744                 return -EINVAL;
 745         }
 746         features = le64_to_cpu(sbp->s_feature_compat_ro) &
 747                 ~NILFS_FEATURE_COMPAT_RO_SUPP;
 748         if (!(sb->s_flags & MS_RDONLY) && features) {
 749                 printk(KERN_ERR "NILFS: couldn't mount RDWR because of "
 750                        "unsupported optional features (%llx)\n",
 751                        (unsigned long long)features);
 752                 return -EINVAL;
 753         }
 754         return 0;
 755 }
 756
 757 static int nilfs_get_root_dentry(struct super_block *sb,
 758                                  struct nilfs_root *root,
 759                                  struct dentry **root_dentry)
 760 {
 761         struct inode *inode;
 762         struct dentry *dentry;
 763         int ret = 0;
 764
 765         inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
 766         if (IS_ERR(inode)) {
 767                 printk(KERN_ERR "NILFS: get root inode failed\n");
 768                 ret = PTR_ERR(inode);
 769                 goto out;
 770         }
 771         if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
 772                 iput(inode);
 773                 printk(KERN_ERR "NILFS: corrupt root inode.\n");
 774                 ret = -EINVAL;
 775                 goto out;
 776         }
 777
 778         if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
 779                 dentry = d_find_alias(inode);
 780                 if (!dentry) {
 781                         dentry = d_alloc_root(inode);
 782                         if (!dentry) {
 783                                 iput(inode);
 784                                 ret = -ENOMEM;
 785                                 goto failed_dentry;
 786                         }
 787                 } else {
 788                         iput(inode);
 789                 }
 790         } else {
 791                 dentry = d_obtain_alias(inode);
 792                 if (IS_ERR(dentry)) {
 793                         ret = PTR_ERR(dentry);
 794                         goto failed_dentry;
 795                 }
 796         }
 797         *root_dentry = dentry;
 798  out:
 799         return ret;
 800
 801  failed_dentry:
 802         printk(KERN_ERR "NILFS: get root dentry failed\n");
 803         goto out;
 804 }
 805
 806 static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 807                                  struct dentry **root_dentry)
 808 {
 809         struct the_nilfs *nilfs = NILFS_SB(s)->s_nilfs;
 810         struct nilfs_root *root;
 811         int ret;
 812
 813         down_read(&nilfs->ns_segctor_sem);
 814         ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
 815         up_read(&nilfs->ns_segctor_sem);
 816         if (ret < 0) {
 817                 ret = (ret == -ENOENT) ? -EINVAL : ret;
 818                 goto out;
 819         } else if (!ret) {
 820                 printk(KERN_ERR "NILFS: The specified checkpoint is "
 821                        "not a snapshot (checkpoint number=%llu).\n",
 822                        (unsigned long long)cno);
 823                 ret = -EINVAL;
 824                 goto out;
 825         }
 826
 827         ret = nilfs_attach_checkpoint(NILFS_SB(s), cno, false, &root);
 828         if (ret) {
 829                 printk(KERN_ERR "NILFS: error loading snapshot "
 830                        "(checkpoint number=%llu).\n",
 831                (unsigned long long)cno);
 832                 goto out;
 833         }
 834         ret = nilfs_get_root_dentry(s, root, root_dentry);
 835         nilfs_put_root(root);
 836  out:
 837         return ret;
 838 }
 839
 840 static int nilfs_tree_was_touched(struct dentry *root_dentry)
 841 {
 842         return atomic_read(&root_dentry->d_count) > 1;
 843 }
 844
 845 /**
 846  * nilfs_try_to_shrink_tree() - try to shrink dentries of a checkpoint
 847  * @root_dentry: root dentry of the tree to be shrunk
 848  *
 849  * This function returns true if the tree was in-use.
 850  */
 851 static int nilfs_try_to_shrink_tree(struct dentry *root_dentry)
 852 {
 853         if (have_submounts(root_dentry))
 854                 return true;
 855         shrink_dcache_parent(root_dentry);
 856         return nilfs_tree_was_touched(root_dentry);
 857 }
 858
 859 int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
 860 {
 861         struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
 862         struct nilfs_root *root;
 863         struct inode *inode;
 864         struct dentry *dentry;
 865         int ret;
 866
 867         if (cno < 0 || cno > nilfs->ns_cno)
 868                 return false;
 869
 870         if (cno >= nilfs_last_cno(nilfs))
 871                 return true;    /* protect recent checkpoints */
 872
 873         ret = false;
 874         root = nilfs_lookup_root(NILFS_SB(sb)->s_nilfs, cno);
 875         if (root) {
 876                 inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
 877                 if (inode) {
 878                         dentry = d_find_alias(inode);
 879                         if (dentry) {
 880                                 if (nilfs_tree_was_touched(dentry))
 881                                         ret = nilfs_try_to_shrink_tree(dentry);
 882                                 dput(dentry);
 883                         }
 884                         iput(inode);
 885                 }
 886                 nilfs_put_root(root);
 887         }
 888         return ret;
 889 }
 890
 891 /**
 892  * nilfs_fill_super() - initialize a super block instance
 893  * @sb: super_block
 894  * @data: mount options
 895  * @silent: silent mode flag
 896  *
 897  * This function is called exclusively by nilfs->ns_mount_mutex.
 898  * So, the recovery process is protected from other simultaneous mounts.
 899  */
 900 static int
 901 nilfs_fill_super(struct super_block *sb, void *data, int silent)
 902 {
 903         struct the_nilfs *nilfs;
 904         struct nilfs_sb_info *sbi;
 905         struct nilfs_root *fsroot;
 906         struct backing_dev_info *bdi;
 907         __u64 cno;
 908         int err;
 909
 910         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 911         if (!sbi)
 912                 return -ENOMEM;
 913
 914         sb->s_fs_info = sbi;
 915         sbi->s_super = sb;
 916
 917         nilfs = alloc_nilfs(sb->s_bdev);
 918         if (!nilfs) {
 919                 err = -ENOMEM;
 920                 goto failed_sbi;
 921         }
 922         sbi->s_nilfs = nilfs;
 923
 924         err = init_nilfs(nilfs, sbi, (char *)data);
 925         if (err)
 926                 goto failed_nilfs;
 927
 928         spin_lock_init(&sbi->s_inode_lock);
 929         INIT_LIST_HEAD(&sbi->s_dirty_files);
 930
 931         /*
 932          * Following initialization is overlapped because
 933          * nilfs_sb_info structure has been cleared at the beginning.
 934          * But we reserve them to keep our interest and make ready
 935          * for the future change.
 936          */
 937         get_random_bytes(&sbi->s_next_generation,
 938                          sizeof(sbi->s_next_generation));
 939         spin_lock_init(&sbi->s_next_gen_lock);
 940
 941         sb->s_op = &nilfs_sops;
 942         sb->s_export_op = &nilfs_export_ops;
 943         sb->s_root = NULL;
 944         sb->s_time_gran = 1;
 945
 946         bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
 947         sb->s_bdi = bdi ? : &default_backing_dev_info;
 948
 949         err = load_nilfs(nilfs, sbi);
 950         if (err)
 951                 goto failed_nilfs;
 952
 953         cno = nilfs_last_cno(nilfs);
 954         err = nilfs_attach_checkpoint(sbi, cno, true, &fsroot);
 955         if (err) {
 956                 printk(KERN_ERR "NILFS: error loading last checkpoint "
 957                        "(checkpoint number=%llu).\n", (unsigned long long)cno);
 958                 goto failed_unload;
 959         }
 960
 961         if (!(sb->s_flags & MS_RDONLY)) {
 962                 err = nilfs_attach_segment_constructor(sbi, fsroot);
 963                 if (err)
 964                         goto failed_checkpoint;
 965         }
 966
 967         err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
 968         if (err)
 969                 goto failed_segctor;
 970
 971         nilfs_put_root(fsroot);
 972
 973         if (!(sb->s_flags & MS_RDONLY)) {
 974                 down_write(&nilfs->ns_sem);
 975                 nilfs_setup_super(sbi, true);
 976                 up_write(&nilfs->ns_sem);
 977         }
 978
 979         return 0;
 980
 981  failed_segctor:
 982         nilfs_detach_segment_constructor(sbi);
 983
 984  failed_checkpoint:
 985         nilfs_put_root(fsroot);
 986
 987  failed_unload:
 988         iput(nilfs->ns_sufile);
 989         iput(nilfs->ns_cpfile);
 990         iput(nilfs->ns_dat);
 991
 992  failed_nilfs:
 993         destroy_nilfs(nilfs);
 994
 995  failed_sbi:
 996         sb->s_fs_info = NULL;
 997         kfree(sbi);
 998         return err;
 999 }
1000
1001 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
1002 {
1003         struct nilfs_sb_info *sbi = NILFS_SB(sb);
1004         struct the_nilfs *nilfs = sbi->s_nilfs;
1005         unsigned long old_sb_flags;
1006         struct nilfs_mount_options old_opts;
1007         int err;
1008
1009         old_sb_flags = sb->s_flags;
1010         old_opts.mount_opt = sbi->s_mount_opt;
1011
1012         if (!parse_options(data, sb, 1)) {
1013                 err = -EINVAL;
1014                 goto restore_opts;
1015         }
1016         sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
1017
1018         err = -EINVAL;
1019
1020         if (!nilfs_valid_fs(nilfs)) {
1021                 printk(KERN_WARNING "NILFS (device %s): couldn't "
1022                        "remount because the filesystem is in an "
1023                        "incomplete recovery state.\n", sb->s_id);
1024                 goto restore_opts;
1025         }
1026
1027         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1028                 goto out;
1029         if (*flags & MS_RDONLY) {
1030                 /* Shutting down the segment constructor */
1031                 nilfs_detach_segment_constructor(sbi);
1032                 sb->s_flags |= MS_RDONLY;
1033
1034                 /*
1035                  * Remounting a valid RW partition RDONLY, so set
1036                  * the RDONLY flag and then mark the partition as valid again.
1037                  */
1038                 down_write(&nilfs->ns_sem);
1039                 nilfs_cleanup_super(sbi);
1040                 up_write(&nilfs->ns_sem);
1041         } else {
1042                 __u64 features;
1043                 struct nilfs_root *root;
1044
1045                 /*
1046                  * Mounting a RDONLY partition read-write, so reread and
1047                  * store the current valid flag.  (It may have been changed
1048                  * by fsck since we originally mounted the partition.)
1049                  */
1050                 down_read(&nilfs->ns_sem);
1051                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1052                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
1053                 up_read(&nilfs->ns_sem);
1054                 if (features) {
1055                         printk(KERN_WARNING "NILFS (device %s): couldn't "
1056                                "remount RDWR because of unsupported optional "
1057                                "features (%llx)\n",
1058                                sb->s_id, (unsigned long long)features);
1059                         err = -EROFS;
1060                         goto restore_opts;
1061                 }
1062
1063                 sb->s_flags &= ~MS_RDONLY;
1064
1065                 root = NILFS_I(sb->s_root->d_inode)->i_root;
1066                 err = nilfs_attach_segment_constructor(sbi, root);
1067                 if (err)
1068                         goto restore_opts;
1069
1070                 down_write(&nilfs->ns_sem);
1071                 nilfs_setup_super(sbi, true);
1072                 up_write(&nilfs->ns_sem);
1073         }
1074  out:
1075         return 0;
1076
1077  restore_opts:
1078         sb->s_flags = old_sb_flags;
1079         sbi->s_mount_opt = old_opts.mount_opt;
1080         return err;
1081 }
1082
1083 struct nilfs_super_data {
1084         struct block_device *bdev;
1085         struct nilfs_sb_info *sbi;
1086         __u64 cno;
1087         int flags;
1088 };
1089
1090 /**
1091  * nilfs_identify - pre-read mount options needed to identify mount instance
1092  * @data: mount options
1093  * @sd: nilfs_super_data
1094  */
1095 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1096 {
1097         char *p, *options = data;
1098         substring_t args[MAX_OPT_ARGS];
1099         int token;
1100         int ret = 0;
1101
1102         do {
1103                 p = strsep(&options, ",");
1104                 if (p != NULL && *p) {
1105                         token = match_token(p, tokens, args);
1106                         if (token == Opt_snapshot) {
1107                                 if (!(sd->flags & MS_RDONLY)) {
1108                                         ret++;
1109                                 } else {
1110                                         sd->cno = simple_strtoull(args[0].from,
1111                                                                   NULL, 0);
1112                                         /*
1113                                          * No need to see the end pointer;
1114                                          * match_token() has done syntax
1115                                          * checking.
1116                                          */
1117                                         if (sd->cno == 0)
1118                                                 ret++;
1119                                 }
1120                         }
1121                         if (ret)
1122                                 printk(KERN_ERR
1123                                        "NILFS: invalid mount option: %s\n", p);
1124                 }
1125                 if (!options)
1126                         break;
1127                 BUG_ON(options == data);
1128                 *(options - 1) = ',';
1129         } while (!ret);
1130         return ret;
1131 }
1132
1133 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1134 {
1135         s->s_bdev = data;
1136         s->s_dev = s->s_bdev->bd_dev;
1137         return 0;
1138 }
1139
1140 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1141 {
1142         return (void *)s->s_bdev == data;
1143 }
1144
1145 static struct dentry *
1146 nilfs_mount(struct file_system_type *fs_type, int flags,
1147              const char *dev_name, void *data)
1148 {
1149         struct nilfs_super_data sd;
1150         struct super_block *s;
1151         fmode_t mode = FMODE_READ;
1152         struct dentry *root_dentry;
1153         int err, s_new = false;
1154
1155         if (!(flags & MS_RDONLY))
1156                 mode |= FMODE_WRITE;
1157
1158         sd.bdev = open_bdev_exclusive(dev_name, mode, fs_type);
1159         if (IS_ERR(sd.bdev))
1160                 return ERR_CAST(sd.bdev);
1161
1162         sd.cno = 0;
1163         sd.flags = flags;
1164         if (nilfs_identify((char *)data, &sd)) {
1165                 err = -EINVAL;
1166                 goto failed;
1167         }
1168
1169         /*
1170          * once the super is inserted into the list by sget, s_umount
1171          * will protect the lockfs code from trying to start a snapshot
1172          * while we are mounting
1173          */
1174         mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
1175         if (sd.bdev->bd_fsfreeze_count > 0) {
1176                 mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1177                 err = -EBUSY;
1178                 goto failed;
1179         }
1180         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, sd.bdev);
1181         mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1182         if (IS_ERR(s)) {
1183                 err = PTR_ERR(s);
1184                 goto failed;
1185         }
1186
1187         if (!s->s_root) {
1188                 char b[BDEVNAME_SIZE];
1189
1190                 s_new = true;
1191
1192                 /* New superblock instance created */
1193                 s->s_flags = flags;
1194                 s->s_mode = mode;
1195                 strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
1196                 sb_set_blocksize(s, block_size(sd.bdev));
1197
1198                 err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
1199                 if (err)
1200                         goto failed_super;
1201
1202                 s->s_flags |= MS_ACTIVE;
1203         } else if (!sd.cno) {
1204                 int busy = false;
1205
1206                 if (nilfs_tree_was_touched(s->s_root)) {
1207                         busy = nilfs_try_to_shrink_tree(s->s_root);
1208                         if (busy && (flags ^ s->s_flags) & MS_RDONLY) {
1209                                 printk(KERN_ERR "NILFS: the device already "
1210                                        "has a %s mount.\n",
1211                                        (s->s_flags & MS_RDONLY) ?
1212                                        "read-only" : "read/write");
1213                                 err = -EBUSY;
1214                                 goto failed_super;
1215                         }
1216                 }
1217                 if (!busy) {
1218                         /*
1219                          * Try remount to setup mount states if the current
1220                          * tree is not mounted and only snapshots use this sb.
1221                          */
1222                         err = nilfs_remount(s, &flags, data);
1223                         if (err)
1224                                 goto failed_super;
1225                 }
1226         }
1227
1228         if (sd.cno) {
1229                 err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
1230                 if (err)
1231                         goto failed_super;
1232         } else {
1233                 root_dentry = dget(s->s_root);
1234         }
1235
1236         if (!s_new)
1237                 close_bdev_exclusive(sd.bdev, mode);
1238
1239         return root_dentry;
1240
1241  failed_super:
1242         deactivate_locked_super(s);
1243
1244  failed:
1245         if (!s_new)
1246                 close_bdev_exclusive(sd.bdev, mode);
1247         return ERR_PTR(err);
1248 }
1249
1250 struct file_system_type nilfs_fs_type = {
1251         .owner    = THIS_MODULE,
1252         .name     = "nilfs2",
1253         .mount    = nilfs_mount,
1254         .kill_sb  = kill_block_super,
1255         .fs_flags = FS_REQUIRES_DEV,
1256 };
1257
1258 static void nilfs_inode_init_once(void *obj)
1259 {
1260         struct nilfs_inode_info *ii = obj;
1261
1262         INIT_LIST_HEAD(&ii->i_dirty);
1263 #ifdef CONFIG_NILFS_XATTR
1264         init_rwsem(&ii->xattr_sem);
1265 #endif
1266         nilfs_btnode_cache_init_once(&ii->i_btnode_cache);
1267         ii->i_bmap = &ii->i_bmap_data;
1268         inode_init_once(&ii->vfs_inode);
1269 }
1270
1271 static void nilfs_segbuf_init_once(void *obj)
1272 {
1273         memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1274 }
1275
1276 static void nilfs_destroy_cachep(void)
1277 {
1278         if (nilfs_inode_cachep)
1279                 kmem_cache_destroy(nilfs_inode_cachep);
1280         if (nilfs_transaction_cachep)
1281                 kmem_cache_destroy(nilfs_transaction_cachep);
1282         if (nilfs_segbuf_cachep)
1283                 kmem_cache_destroy(nilfs_segbuf_cachep);
1284         if (nilfs_btree_path_cache)
1285                 kmem_cache_destroy(nilfs_btree_path_cache);
1286 }
1287
1288 static int __init nilfs_init_cachep(void)
1289 {
1290         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1291                         sizeof(struct nilfs_inode_info), 0,
1292                         SLAB_RECLAIM_ACCOUNT, nilfs_inode_init_once);
1293         if (!nilfs_inode_cachep)
1294                 goto fail;
1295
1296         nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1297                         sizeof(struct nilfs_transaction_info), 0,
1298                         SLAB_RECLAIM_ACCOUNT, NULL);
1299         if (!nilfs_transaction_cachep)
1300                 goto fail;
1301
1302         nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1303                         sizeof(struct nilfs_segment_buffer), 0,
1304                         SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1305         if (!nilfs_segbuf_cachep)
1306                 goto fail;
1307
1308         nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1309                         sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1310                         0, 0, NULL);
1311         if (!nilfs_btree_path_cache)
1312                 goto fail;
1313
1314         return 0;
1315
1316 fail:
1317         nilfs_destroy_cachep();
1318         return -ENOMEM;
1319 }
1320
1321 static int __init init_nilfs_fs(void)
1322 {
1323         int err;
1324
1325         err = nilfs_init_cachep();
1326         if (err)
1327                 goto fail;
1328
1329         err = register_filesystem(&nilfs_fs_type);
1330         if (err)
1331                 goto free_cachep;
1332
1333         printk(KERN_INFO "NILFS version 2 loaded\n");
1334         return 0;
1335
1336 free_cachep:
1337         nilfs_destroy_cachep();
1338 fail:
1339         return err;
1340 }
1341
1342 static void __exit exit_nilfs_fs(void)
1343 {
1344         nilfs_destroy_cachep();
1345         unregister_filesystem(&nilfs_fs_type);
1346 }
1347
1348 module_init(init_nilfs_fs)
1349 module_exit(exit_nilfs_fs)