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   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/smp_lock.h>
  49 #include <linux/vfs.h>
  50 #include <linux/writeback.h>
  51 #include <linux/kobject.h>
  52 #include <linux/exportfs.h>
  53 #include "nilfs.h"
  54 #include "mdt.h"
  55 #include "alloc.h"
  56 #include "page.h"
  57 #include "cpfile.h"
  58 #include "ifile.h"
  59 #include "dat.h"
  60 #include "segment.h"
  61 #include "segbuf.h"
  62
  63 MODULE_AUTHOR("NTT Corp.");
  64 MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
  65                    "(NILFS)");
  66 MODULE_LICENSE("GPL");
  67
  68 static void nilfs_write_super(struct super_block *sb);
  69 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
  70
  71 /**
  72  * nilfs_error() - report failure condition on a filesystem
  73  *
  74  * nilfs_error() sets an ERROR_FS flag on the superblock as well as
  75  * reporting an error message.  It should be called when NILFS detects
  76  * incoherences or defects of meta data on disk.  As for sustainable
  77  * errors such as a single-shot I/O error, nilfs_warning() or the printk()
  78  * function should be used instead.
  79  *
  80  * The segment constructor must not call this function because it can
  81  * kill itself.
  82  */
  83 void nilfs_error(struct super_block *sb, const char *function,
  84                  const char *fmt, ...)
  85 {
  86         struct nilfs_sb_info *sbi = NILFS_SB(sb);
  87         va_list args;
  88
  89         va_start(args, fmt);
  90         printk(KERN_CRIT "NILFS error (device %s): %s: ", sb->s_id, function);
  91         vprintk(fmt, args);
  92         printk("\n");
  93         va_end(args);
  94
  95         if (!(sb->s_flags & MS_RDONLY)) {
  96                 struct the_nilfs *nilfs = sbi->s_nilfs;
  97
  98                 if (!nilfs_test_opt(sbi, ERRORS_CONT))
  99                         nilfs_detach_segment_constructor(sbi);
 100
 101                 down_write(&nilfs->ns_sem);
 102                 if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
 103                         nilfs->ns_mount_state |= NILFS_ERROR_FS;
 104                         nilfs->ns_sbp[0]->s_state |=
 105                                 cpu_to_le16(NILFS_ERROR_FS);
 106                         nilfs_commit_super(sbi, 1);
 107                 }
 108                 up_write(&nilfs->ns_sem);
 109
 110                 if (nilfs_test_opt(sbi, ERRORS_RO)) {
 111                         printk(KERN_CRIT "Remounting filesystem read-only\n");
 112                         sb->s_flags |= MS_RDONLY;
 113                 }
 114         }
 115
 116         if (nilfs_test_opt(sbi, ERRORS_PANIC))
 117                 panic("NILFS (device %s): panic forced after error\n",
 118                       sb->s_id);
 119 }
 120
 121 void nilfs_warning(struct super_block *sb, const char *function,
 122                    const char *fmt, ...)
 123 {
 124         va_list args;
 125
 126         va_start(args, fmt);
 127         printk(KERN_WARNING "NILFS warning (device %s): %s: ",
 128                sb->s_id, function);
 129         vprintk(fmt, args);
 130         printk("\n");
 131         va_end(args);
 132 }
 133
 134 static struct kmem_cache *nilfs_inode_cachep;
 135
 136 struct inode *nilfs_alloc_inode(struct super_block *sb)
 137 {
 138         struct nilfs_inode_info *ii;
 139
 140         ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
 141         if (!ii)
 142                 return NULL;
 143         ii->i_bh = NULL;
 144         ii->i_state = 0;
 145         ii->vfs_inode.i_version = 1;
 146         nilfs_btnode_cache_init(&ii->i_btnode_cache);
 147         return &ii->vfs_inode;
 148 }
 149
 150 void nilfs_destroy_inode(struct inode *inode)
 151 {
 152         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 153 }
 154
 155 static void init_once(void *obj)
 156 {
 157         struct nilfs_inode_info *ii = obj;
 158
 159         INIT_LIST_HEAD(&ii->i_dirty);
 160 #ifdef CONFIG_NILFS_XATTR
 161         init_rwsem(&ii->xattr_sem);
 162 #endif
 163         nilfs_btnode_cache_init_once(&ii->i_btnode_cache);
 164         ii->i_bmap = (struct nilfs_bmap *)&ii->i_bmap_union;
 165         inode_init_once(&ii->vfs_inode);
 166 }
 167
 168 static int nilfs_init_inode_cache(void)
 169 {
 170         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
 171                                                sizeof(struct nilfs_inode_info),
 172                                                0, SLAB_RECLAIM_ACCOUNT,
 173                                                init_once);
 174
 175         return (nilfs_inode_cachep == NULL) ? -ENOMEM : 0;
 176 }
 177
 178 static inline void nilfs_destroy_inode_cache(void)
 179 {
 180         kmem_cache_destroy(nilfs_inode_cachep);
 181 }
 182
 183 static void nilfs_clear_inode(struct inode *inode)
 184 {
 185         struct nilfs_inode_info *ii = NILFS_I(inode);
 186
 187 #ifdef CONFIG_NILFS_POSIX_ACL
 188         if (ii->i_acl && ii->i_acl != NILFS_ACL_NOT_CACHED) {
 189                 posix_acl_release(ii->i_acl);
 190                 ii->i_acl = NILFS_ACL_NOT_CACHED;
 191         }
 192         if (ii->i_default_acl && ii->i_default_acl != NILFS_ACL_NOT_CACHED) {
 193                 posix_acl_release(ii->i_default_acl);
 194                 ii->i_default_acl = NILFS_ACL_NOT_CACHED;
 195         }
 196 #endif
 197         /*
 198          * Free resources allocated in nilfs_read_inode(), here.
 199          */
 200         BUG_ON(!list_empty(&ii->i_dirty));
 201         brelse(ii->i_bh);
 202         ii->i_bh = NULL;
 203
 204         if (test_bit(NILFS_I_BMAP, &ii->i_state))
 205                 nilfs_bmap_clear(ii->i_bmap);
 206
 207         nilfs_btnode_cache_clear(&ii->i_btnode_cache);
 208 }
 209
 210 static int nilfs_sync_super(struct nilfs_sb_info *sbi, int dupsb)
 211 {
 212         struct the_nilfs *nilfs = sbi->s_nilfs;
 213         int err;
 214         int barrier_done = 0;
 215
 216         if (nilfs_test_opt(sbi, BARRIER)) {
 217                 set_buffer_ordered(nilfs->ns_sbh[0]);
 218                 barrier_done = 1;
 219         }
 220  retry:
 221         set_buffer_dirty(nilfs->ns_sbh[0]);
 222         err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 223         if (err == -EOPNOTSUPP && barrier_done) {
 224                 nilfs_warning(sbi->s_super, __func__,
 225                               "barrier-based sync failed. "
 226                               "disabling barriers\n");
 227                 nilfs_clear_opt(sbi, BARRIER);
 228                 barrier_done = 0;
 229                 clear_buffer_ordered(nilfs->ns_sbh[0]);
 230                 goto retry;
 231         }
 232         if (unlikely(err)) {
 233                 printk(KERN_ERR
 234                        "NILFS: unable to write superblock (err=%d)\n", err);
 235                 if (err == -EIO && nilfs->ns_sbh[1]) {
 236                         nilfs_fall_back_super_block(nilfs);
 237                         goto retry;
 238                 }
 239         } else {
 240                 struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 241
 242                 /*
 243                  * The latest segment becomes trailable from the position
 244                  * written in superblock.
 245                  */
 246                 clear_nilfs_discontinued(nilfs);
 247
 248                 /* update GC protection for recent segments */
 249                 if (nilfs->ns_sbh[1]) {
 250                         sbp = NULL;
 251                         if (dupsb) {
 252                                 set_buffer_dirty(nilfs->ns_sbh[1]);
 253                                 if (!sync_dirty_buffer(nilfs->ns_sbh[1]))
 254                                         sbp = nilfs->ns_sbp[1];
 255                         }
 256                 }
 257                 if (sbp) {
 258                         spin_lock(&nilfs->ns_last_segment_lock);
 259                         nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
 260                         spin_unlock(&nilfs->ns_last_segment_lock);
 261                 }
 262         }
 263
 264         return err;
 265 }
 266
 267 int nilfs_commit_super(struct nilfs_sb_info *sbi, int dupsb)
 268 {
 269         struct the_nilfs *nilfs = sbi->s_nilfs;
 270         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 271         sector_t nfreeblocks;
 272         time_t t;
 273         int err;
 274
 275         /* nilfs->sem must be locked by the caller. */
 276         if (sbp[0]->s_magic != NILFS_SUPER_MAGIC) {
 277                 if (sbp[1] && sbp[1]->s_magic == NILFS_SUPER_MAGIC)
 278                         nilfs_swap_super_block(nilfs);
 279                 else {
 280                         printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
 281                                sbi->s_super->s_id);
 282                         return -EIO;
 283                 }
 284         }
 285         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 286         if (unlikely(err)) {
 287                 printk(KERN_ERR "NILFS: failed to count free blocks\n");
 288                 return err;
 289         }
 290         spin_lock(&nilfs->ns_last_segment_lock);
 291         sbp[0]->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
 292         sbp[0]->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
 293         sbp[0]->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
 294         spin_unlock(&nilfs->ns_last_segment_lock);
 295
 296         t = get_seconds();
 297         nilfs->ns_sbwtime[0] = t;
 298         sbp[0]->s_free_blocks_count = cpu_to_le64(nfreeblocks);
 299         sbp[0]->s_wtime = cpu_to_le64(t);
 300         sbp[0]->s_sum = 0;
 301         sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 302                                              (unsigned char *)sbp[0],
 303                                              nilfs->ns_sbsize));
 304         if (dupsb && sbp[1]) {
 305                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 306                 nilfs->ns_sbwtime[1] = t;
 307         }
 308         sbi->s_super->s_dirt = 0;
 309         return nilfs_sync_super(sbi, dupsb);
 310 }
 311
 312 static void nilfs_put_super(struct super_block *sb)
 313 {
 314         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 315         struct the_nilfs *nilfs = sbi->s_nilfs;
 316
 317         lock_kernel();
 318
 319         if (sb->s_dirt)
 320                 nilfs_write_super(sb);
 321
 322         nilfs_detach_segment_constructor(sbi);
 323
 324         if (!(sb->s_flags & MS_RDONLY)) {
 325                 down_write(&nilfs->ns_sem);
 326                 nilfs->ns_sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
 327                 nilfs_commit_super(sbi, 1);
 328                 up_write(&nilfs->ns_sem);
 329         }
 330         down_write(&nilfs->ns_sem);
 331         if (nilfs->ns_current == sbi)
 332                 nilfs->ns_current = NULL;
 333         up_write(&nilfs->ns_sem);
 334
 335         nilfs_detach_checkpoint(sbi);
 336         put_nilfs(sbi->s_nilfs);
 337         sbi->s_super = NULL;
 338         sb->s_fs_info = NULL;
 339         kfree(sbi);
 340
 341         unlock_kernel();
 342 }
 343
 344 /**
 345  * nilfs_write_super - write super block(s) of NILFS
 346  * @sb: super_block
 347  *
 348  * nilfs_write_super() gets a fs-dependent lock, writes super block(s), and
 349  * clears s_dirt.  This function is called in the section protected by
 350  * lock_super().
 351  *
 352  * The s_dirt flag is managed by each filesystem and we protect it by ns_sem
 353  * of the struct the_nilfs.  Lock order must be as follows:
 354  *
 355  *   1. lock_super()
 356  *   2.    down_write(&nilfs->ns_sem)
 357  *
 358  * Inside NILFS, locking ns_sem is enough to protect s_dirt and the buffer
 359  * of the super block (nilfs->ns_sbp[]).
 360  *
 361  * In most cases, VFS functions call lock_super() before calling these
 362  * methods.  So we must be careful not to bring on deadlocks when using
 363  * lock_super();  see generic_shutdown_super(), write_super(), and so on.
 364  *
 365  * Note that order of lock_kernel() and lock_super() depends on contexts
 366  * of VFS.  We should also note that lock_kernel() can be used in its
 367  * protective section and only the outermost one has an effect.
 368  */
 369 static void nilfs_write_super(struct super_block *sb)
 370 {
 371         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 372         struct the_nilfs *nilfs = sbi->s_nilfs;
 373
 374         down_write(&nilfs->ns_sem);
 375         if (!(sb->s_flags & MS_RDONLY)) {
 376                 struct nilfs_super_block **sbp = nilfs->ns_sbp;
 377                 u64 t = get_seconds();
 378                 int dupsb;
 379
 380                 if (!nilfs_discontinued(nilfs) && t >= nilfs->ns_sbwtime[0] &&
 381                     t < nilfs->ns_sbwtime[0] + NILFS_SB_FREQ) {
 382                         up_write(&nilfs->ns_sem);
 383                         return;
 384                 }
 385                 dupsb = sbp[1] && t > nilfs->ns_sbwtime[1] + NILFS_ALTSB_FREQ;
 386                 nilfs_commit_super(sbi, dupsb);
 387         }
 388         sb->s_dirt = 0;
 389         up_write(&nilfs->ns_sem);
 390 }
 391
 392 static int nilfs_sync_fs(struct super_block *sb, int wait)
 393 {
 394         int err = 0;
 395
 396         nilfs_write_super(sb);
 397
 398         /* This function is called when super block should be written back */
 399         if (wait)
 400                 err = nilfs_construct_segment(sb);
 401         return err;
 402 }
 403
 404 int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno)
 405 {
 406         struct the_nilfs *nilfs = sbi->s_nilfs;
 407         struct nilfs_checkpoint *raw_cp;
 408         struct buffer_head *bh_cp;
 409         int err;
 410
 411         down_write(&nilfs->ns_sem);
 412         list_add(&sbi->s_list, &nilfs->ns_supers);
 413         up_write(&nilfs->ns_sem);
 414
 415         sbi->s_ifile = nilfs_mdt_new(
 416                 nilfs, sbi->s_super, NILFS_IFILE_INO, NILFS_IFILE_GFP);
 417         if (!sbi->s_ifile)
 418                 return -ENOMEM;
 419
 420         err = nilfs_palloc_init_blockgroup(sbi->s_ifile, nilfs->ns_inode_size);
 421         if (unlikely(err))
 422                 goto failed;
 423
 424         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 425                                           &bh_cp);
 426         if (unlikely(err)) {
 427                 if (err == -ENOENT || err == -EINVAL) {
 428                         printk(KERN_ERR
 429                                "NILFS: Invalid checkpoint "
 430                                "(checkpoint number=%llu)\n",
 431                                (unsigned long long)cno);
 432                         err = -EINVAL;
 433                 }
 434                 goto failed;
 435         }
 436         err = nilfs_read_inode_common(sbi->s_ifile, &raw_cp->cp_ifile_inode);
 437         if (unlikely(err))
 438                 goto failed_bh;
 439         atomic_set(&sbi->s_inodes_count, le64_to_cpu(raw_cp->cp_inodes_count));
 440         atomic_set(&sbi->s_blocks_count, le64_to_cpu(raw_cp->cp_blocks_count));
 441
 442         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 443         return 0;
 444
 445  failed_bh:
 446         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 447  failed:
 448         nilfs_mdt_destroy(sbi->s_ifile);
 449         sbi->s_ifile = NULL;
 450
 451         down_write(&nilfs->ns_sem);
 452         list_del_init(&sbi->s_list);
 453         up_write(&nilfs->ns_sem);
 454
 455         return err;
 456 }
 457
 458 void nilfs_detach_checkpoint(struct nilfs_sb_info *sbi)
 459 {
 460         struct the_nilfs *nilfs = sbi->s_nilfs;
 461
 462         nilfs_mdt_clear(sbi->s_ifile);
 463         nilfs_mdt_destroy(sbi->s_ifile);
 464         sbi->s_ifile = NULL;
 465         down_write(&nilfs->ns_sem);
 466         list_del_init(&sbi->s_list);
 467         up_write(&nilfs->ns_sem);
 468 }
 469
 470 static int nilfs_mark_recovery_complete(struct nilfs_sb_info *sbi)
 471 {
 472         struct the_nilfs *nilfs = sbi->s_nilfs;
 473         int err = 0;
 474
 475         down_write(&nilfs->ns_sem);
 476         if (!(nilfs->ns_mount_state & NILFS_VALID_FS)) {
 477                 nilfs->ns_mount_state |= NILFS_VALID_FS;
 478                 err = nilfs_commit_super(sbi, 1);
 479                 if (likely(!err))
 480                         printk(KERN_INFO "NILFS: recovery complete.\n");
 481         }
 482         up_write(&nilfs->ns_sem);
 483         return err;
 484 }
 485
 486 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 487 {
 488         struct super_block *sb = dentry->d_sb;
 489         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 490         struct the_nilfs *nilfs = sbi->s_nilfs;
 491         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 492         unsigned long long blocks;
 493         unsigned long overhead;
 494         unsigned long nrsvblocks;
 495         sector_t nfreeblocks;
 496         int err;
 497
 498         /*
 499          * Compute all of the segment blocks
 500          *
 501          * The blocks before first segment and after last segment
 502          * are excluded.
 503          */
 504         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 505                 - nilfs->ns_first_data_block;
 506         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 507
 508         /*
 509          * Compute the overhead
 510          *
 511          * When distributing meta data blocks outside semgent structure,
 512          * We must count them as the overhead.
 513          */
 514         overhead = 0;
 515
 516         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 517         if (unlikely(err))
 518                 return err;
 519
 520         buf->f_type = NILFS_SUPER_MAGIC;
 521         buf->f_bsize = sb->s_blocksize;
 522         buf->f_blocks = blocks - overhead;
 523         buf->f_bfree = nfreeblocks;
 524         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 525                 (buf->f_bfree - nrsvblocks) : 0;
 526         buf->f_files = atomic_read(&sbi->s_inodes_count);
 527         buf->f_ffree = 0; /* nilfs_count_free_inodes(sb); */
 528         buf->f_namelen = NILFS_NAME_LEN;
 529         buf->f_fsid.val[0] = (u32)id;
 530         buf->f_fsid.val[1] = (u32)(id >> 32);
 531
 532         return 0;
 533 }
 534
 535 static struct super_operations nilfs_sops = {
 536         .alloc_inode    = nilfs_alloc_inode,
 537         .destroy_inode  = nilfs_destroy_inode,
 538         .dirty_inode    = nilfs_dirty_inode,
 539         /* .write_inode    = nilfs_write_inode, */
 540         /* .put_inode      = nilfs_put_inode, */
 541         /* .drop_inode    = nilfs_drop_inode, */
 542         .delete_inode   = nilfs_delete_inode,
 543         .put_super      = nilfs_put_super,
 544         .write_super    = nilfs_write_super,
 545         .sync_fs        = nilfs_sync_fs,
 546         /* .write_super_lockfs */
 547         /* .unlockfs */
 548         .statfs         = nilfs_statfs,
 549         .remount_fs     = nilfs_remount,
 550         .clear_inode    = nilfs_clear_inode,
 551         /* .umount_begin */
 552         /* .show_options */
 553 };
 554
 555 static struct inode *
 556 nilfs_nfs_get_inode(struct super_block *sb, u64 ino, u32 generation)
 557 {
 558         struct inode *inode;
 559
 560         if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO &&
 561             ino != NILFS_SKETCH_INO)
 562                 return ERR_PTR(-ESTALE);
 563
 564         inode = nilfs_iget(sb, ino);
 565         if (IS_ERR(inode))
 566                 return ERR_CAST(inode);
 567         if (generation && inode->i_generation != generation) {
 568                 iput(inode);
 569                 return ERR_PTR(-ESTALE);
 570         }
 571
 572         return inode;
 573 }
 574
 575 static struct dentry *
 576 nilfs_fh_to_dentry(struct super_block *sb, struct fid *fid, int fh_len,
 577                    int fh_type)
 578 {
 579         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 580                                     nilfs_nfs_get_inode);
 581 }
 582
 583 static struct dentry *
 584 nilfs_fh_to_parent(struct super_block *sb, struct fid *fid, int fh_len,
 585                    int fh_type)
 586 {
 587         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 588                                     nilfs_nfs_get_inode);
 589 }
 590
 591 static struct export_operations nilfs_export_ops = {
 592         .fh_to_dentry = nilfs_fh_to_dentry,
 593         .fh_to_parent = nilfs_fh_to_parent,
 594         .get_parent = nilfs_get_parent,
 595 };
 596
 597 enum {
 598         Opt_err_cont, Opt_err_panic, Opt_err_ro,
 599         Opt_barrier, Opt_snapshot, Opt_order,
 600         Opt_err,
 601 };
 602
 603 static match_table_t tokens = {
 604         {Opt_err_cont, "errors=continue"},
 605         {Opt_err_panic, "errors=panic"},
 606         {Opt_err_ro, "errors=remount-ro"},
 607         {Opt_barrier, "barrier=%s"},
 608         {Opt_snapshot, "cp=%u"},
 609         {Opt_order, "order=%s"},
 610         {Opt_err, NULL}
 611 };
 612
 613 static int match_bool(substring_t *s, int *result)
 614 {
 615         int len = s->to - s->from;
 616
 617         if (strncmp(s->from, "on", len) == 0)
 618                 *result = 1;
 619         else if (strncmp(s->from, "off", len) == 0)
 620                 *result = 0;
 621         else
 622                 return 1;
 623         return 0;
 624 }
 625
 626 static int parse_options(char *options, struct super_block *sb)
 627 {
 628         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 629         char *p;
 630         substring_t args[MAX_OPT_ARGS];
 631         int option;
 632
 633         if (!options)
 634                 return 1;
 635
 636         while ((p = strsep(&options, ",")) != NULL) {
 637                 int token;
 638                 if (!*p)
 639                         continue;
 640
 641                 token = match_token(p, tokens, args);
 642                 switch (token) {
 643                 case Opt_barrier:
 644                         if (match_bool(&args[0], &option))
 645                                 return 0;
 646                         if (option)
 647                                 nilfs_set_opt(sbi, BARRIER);
 648                         else
 649                                 nilfs_clear_opt(sbi, BARRIER);
 650                         break;
 651                 case Opt_order:
 652                         if (strcmp(args[0].from, "relaxed") == 0)
 653                                 /* Ordered data semantics */
 654                                 nilfs_clear_opt(sbi, STRICT_ORDER);
 655                         else if (strcmp(args[0].from, "strict") == 0)
 656                                 /* Strict in-order semantics */
 657                                 nilfs_set_opt(sbi, STRICT_ORDER);
 658                         else
 659                                 return 0;
 660                         break;
 661                 case Opt_err_panic:
 662                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_PANIC);
 663                         break;
 664                 case Opt_err_ro:
 665                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_RO);
 666                         break;
 667                 case Opt_err_cont:
 668                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_CONT);
 669                         break;
 670                 case Opt_snapshot:
 671                         if (match_int(&args[0], &option) || option <= 0)
 672                                 return 0;
 673                         if (!(sb->s_flags & MS_RDONLY))
 674                                 return 0;
 675                         sbi->s_snapshot_cno = option;
 676                         nilfs_set_opt(sbi, SNAPSHOT);
 677                         break;
 678                 default:
 679                         printk(KERN_ERR
 680                                "NILFS: Unrecognized mount option \"%s\"\n", p);
 681                         return 0;
 682                 }
 683         }
 684         return 1;
 685 }
 686
 687 static inline void
 688 nilfs_set_default_options(struct nilfs_sb_info *sbi,
 689                           struct nilfs_super_block *sbp)
 690 {
 691         sbi->s_mount_opt =
 692                 NILFS_MOUNT_ERRORS_CONT | NILFS_MOUNT_BARRIER;
 693 }
 694
 695 static int nilfs_setup_super(struct nilfs_sb_info *sbi)
 696 {
 697         struct the_nilfs *nilfs = sbi->s_nilfs;
 698         struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 699         int max_mnt_count = le16_to_cpu(sbp->s_max_mnt_count);
 700         int mnt_count = le16_to_cpu(sbp->s_mnt_count);
 701
 702         /* nilfs->sem must be locked by the caller. */
 703         if (!(nilfs->ns_mount_state & NILFS_VALID_FS)) {
 704                 printk(KERN_WARNING "NILFS warning: mounting unchecked fs\n");
 705         } else if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 706                 printk(KERN_WARNING
 707                        "NILFS warning: mounting fs with errors\n");
 708 #if 0
 709         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 710                 printk(KERN_WARNING
 711                        "NILFS warning: maximal mount count reached\n");
 712 #endif
 713         }
 714         if (!max_mnt_count)
 715                 sbp->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 716
 717         sbp->s_mnt_count = cpu_to_le16(mnt_count + 1);
 718         sbp->s_state = cpu_to_le16(le16_to_cpu(sbp->s_state) & ~NILFS_VALID_FS);
 719         sbp->s_mtime = cpu_to_le64(get_seconds());
 720         return nilfs_commit_super(sbi, 1);
 721 }
 722
 723 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 724                                                  u64 pos, int blocksize,
 725                                                  struct buffer_head **pbh)
 726 {
 727         unsigned long long sb_index = pos;
 728         unsigned long offset;
 729
 730         offset = do_div(sb_index, blocksize);
 731         *pbh = sb_bread(sb, sb_index);
 732         if (!*pbh)
 733                 return NULL;
 734         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 735 }
 736
 737 int nilfs_store_magic_and_option(struct super_block *sb,
 738                                  struct nilfs_super_block *sbp,
 739                                  char *data)
 740 {
 741         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 742
 743         sb->s_magic = le16_to_cpu(sbp->s_magic);
 744
 745         /* FS independent flags */
 746 #ifdef NILFS_ATIME_DISABLE
 747         sb->s_flags |= MS_NOATIME;
 748 #endif
 749
 750         nilfs_set_default_options(sbi, sbp);
 751
 752         sbi->s_resuid = le16_to_cpu(sbp->s_def_resuid);
 753         sbi->s_resgid = le16_to_cpu(sbp->s_def_resgid);
 754         sbi->s_interval = le32_to_cpu(sbp->s_c_interval);
 755         sbi->s_watermark = le32_to_cpu(sbp->s_c_block_max);
 756
 757         return !parse_options(data, sb) ? -EINVAL : 0 ;
 758 }
 759
 760 /**
 761  * nilfs_fill_super() - initialize a super block instance
 762  * @sb: super_block
 763  * @data: mount options
 764  * @silent: silent mode flag
 765  * @nilfs: the_nilfs struct
 766  *
 767  * This function is called exclusively by bd_mount_mutex.
 768  * So, the recovery process is protected from other simultaneous mounts.
 769  */
 770 static int
 771 nilfs_fill_super(struct super_block *sb, void *data, int silent,
 772                  struct the_nilfs *nilfs)
 773 {
 774         struct nilfs_sb_info *sbi;
 775         struct inode *root;
 776         __u64 cno;
 777         int err;
 778
 779         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 780         if (!sbi)
 781                 return -ENOMEM;
 782
 783         sb->s_fs_info = sbi;
 784
 785         get_nilfs(nilfs);
 786         sbi->s_nilfs = nilfs;
 787         sbi->s_super = sb;
 788
 789         err = init_nilfs(nilfs, sbi, (char *)data);
 790         if (err)
 791                 goto failed_sbi;
 792
 793         spin_lock_init(&sbi->s_inode_lock);
 794         INIT_LIST_HEAD(&sbi->s_dirty_files);
 795         INIT_LIST_HEAD(&sbi->s_list);
 796
 797         /*
 798          * Following initialization is overlapped because
 799          * nilfs_sb_info structure has been cleared at the beginning.
 800          * But we reserve them to keep our interest and make ready
 801          * for the future change.
 802          */
 803         get_random_bytes(&sbi->s_next_generation,
 804                          sizeof(sbi->s_next_generation));
 805         spin_lock_init(&sbi->s_next_gen_lock);
 806
 807         sb->s_op = &nilfs_sops;
 808         sb->s_export_op = &nilfs_export_ops;
 809         sb->s_root = NULL;
 810         sb->s_time_gran = 1;
 811
 812         if (!nilfs_loaded(nilfs)) {
 813                 err = load_nilfs(nilfs, sbi);
 814                 if (err)
 815                         goto failed_sbi;
 816         }
 817         cno = nilfs_last_cno(nilfs);
 818
 819         if (sb->s_flags & MS_RDONLY) {
 820                 if (nilfs_test_opt(sbi, SNAPSHOT)) {
 821                         err = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile,
 822                                                        sbi->s_snapshot_cno);
 823                         if (err < 0)
 824                                 goto failed_sbi;
 825                         if (!err) {
 826                                 printk(KERN_ERR
 827                                        "NILFS: The specified checkpoint is "
 828                                        "not a snapshot "
 829                                        "(checkpoint number=%llu).\n",
 830                                        (unsigned long long)sbi->s_snapshot_cno);
 831                                 err = -EINVAL;
 832                                 goto failed_sbi;
 833                         }
 834                         cno = sbi->s_snapshot_cno;
 835                 } else
 836                         /* Read-only mount */
 837                         sbi->s_snapshot_cno = cno;
 838         }
 839
 840         err = nilfs_attach_checkpoint(sbi, cno);
 841         if (err) {
 842                 printk(KERN_ERR "NILFS: error loading a checkpoint"
 843                        " (checkpoint number=%llu).\n", (unsigned long long)cno);
 844                 goto failed_sbi;
 845         }
 846
 847         if (!(sb->s_flags & MS_RDONLY)) {
 848                 err = nilfs_attach_segment_constructor(sbi);
 849                 if (err)
 850                         goto failed_checkpoint;
 851         }
 852
 853         root = nilfs_iget(sb, NILFS_ROOT_INO);
 854         if (IS_ERR(root)) {
 855                 printk(KERN_ERR "NILFS: get root inode failed\n");
 856                 err = PTR_ERR(root);
 857                 goto failed_segctor;
 858         }
 859         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 860                 iput(root);
 861                 printk(KERN_ERR "NILFS: corrupt root inode.\n");
 862                 err = -EINVAL;
 863                 goto failed_segctor;
 864         }
 865         sb->s_root = d_alloc_root(root);
 866         if (!sb->s_root) {
 867                 iput(root);
 868                 printk(KERN_ERR "NILFS: get root dentry failed\n");
 869                 err = -ENOMEM;
 870                 goto failed_segctor;
 871         }
 872
 873         if (!(sb->s_flags & MS_RDONLY)) {
 874                 down_write(&nilfs->ns_sem);
 875                 nilfs_setup_super(sbi);
 876                 up_write(&nilfs->ns_sem);
 877         }
 878
 879         err = nilfs_mark_recovery_complete(sbi);
 880         if (unlikely(err)) {
 881                 printk(KERN_ERR "NILFS: recovery failed.\n");
 882                 goto failed_root;
 883         }
 884
 885         down_write(&nilfs->ns_sem);
 886         if (!nilfs_test_opt(sbi, SNAPSHOT))
 887                 nilfs->ns_current = sbi;
 888         up_write(&nilfs->ns_sem);
 889
 890         return 0;
 891
 892  failed_root:
 893         dput(sb->s_root);
 894         sb->s_root = NULL;
 895
 896  failed_segctor:
 897         nilfs_detach_segment_constructor(sbi);
 898
 899  failed_checkpoint:
 900         nilfs_detach_checkpoint(sbi);
 901
 902  failed_sbi:
 903         put_nilfs(nilfs);
 904         sb->s_fs_info = NULL;
 905         kfree(sbi);
 906         return err;
 907 }
 908
 909 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
 910 {
 911         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 912         struct nilfs_super_block *sbp;
 913         struct the_nilfs *nilfs = sbi->s_nilfs;
 914         unsigned long old_sb_flags;
 915         struct nilfs_mount_options old_opts;
 916         int err;
 917
 918         lock_kernel();
 919
 920         old_sb_flags = sb->s_flags;
 921         old_opts.mount_opt = sbi->s_mount_opt;
 922         old_opts.snapshot_cno = sbi->s_snapshot_cno;
 923
 924         if (!parse_options(data, sb)) {
 925                 err = -EINVAL;
 926                 goto restore_opts;
 927         }
 928         sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
 929
 930         if ((*flags & MS_RDONLY) &&
 931             sbi->s_snapshot_cno != old_opts.snapshot_cno) {
 932                 printk(KERN_WARNING "NILFS (device %s): couldn't "
 933                        "remount to a different snapshot. \n",
 934                        sb->s_id);
 935                 err = -EINVAL;
 936                 goto restore_opts;
 937         }
 938
 939         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 940                 goto out;
 941         if (*flags & MS_RDONLY) {
 942                 /* Shutting down the segment constructor */
 943                 nilfs_detach_segment_constructor(sbi);
 944                 sb->s_flags |= MS_RDONLY;
 945
 946                 sbi->s_snapshot_cno = nilfs_last_cno(nilfs);
 947                 /* nilfs_set_opt(sbi, SNAPSHOT); */
 948
 949                 /*
 950                  * Remounting a valid RW partition RDONLY, so set
 951                  * the RDONLY flag and then mark the partition as valid again.
 952                  */
 953                 down_write(&nilfs->ns_sem);
 954                 sbp = nilfs->ns_sbp[0];
 955                 if (!(sbp->s_state & le16_to_cpu(NILFS_VALID_FS)) &&
 956                     (nilfs->ns_mount_state & NILFS_VALID_FS))
 957                         sbp->s_state = cpu_to_le16(nilfs->ns_mount_state);
 958                 sbp->s_mtime = cpu_to_le64(get_seconds());
 959                 nilfs_commit_super(sbi, 1);
 960                 up_write(&nilfs->ns_sem);
 961         } else {
 962                 /*
 963                  * Mounting a RDONLY partition read-write, so reread and
 964                  * store the current valid flag.  (It may have been changed
 965                  * by fsck since we originally mounted the partition.)
 966                  */
 967                 down(&sb->s_bdev->bd_mount_sem);
 968                 down_read(&nilfs->ns_sem);
 969                 if (nilfs->ns_current && nilfs->ns_current != sbi) {
 970                         printk(KERN_WARNING "NILFS (device %s): couldn't "
 971                                "remount because an RW-mount exists.\n",
 972                                sb->s_id);
 973                         up_read(&nilfs->ns_sem);
 974                         err = -EBUSY;
 975                         goto rw_remount_failed;
 976                 }
 977                 up_read(&nilfs->ns_sem);
 978                 if (sbi->s_snapshot_cno != nilfs_last_cno(nilfs)) {
 979                         printk(KERN_WARNING "NILFS (device %s): couldn't "
 980                                "remount because the current RO-mount is not "
 981                                "the latest one.\n",
 982                                sb->s_id);
 983                         err = -EINVAL;
 984                         goto rw_remount_failed;
 985                 }
 986                 sb->s_flags &= ~MS_RDONLY;
 987                 nilfs_clear_opt(sbi, SNAPSHOT);
 988                 sbi->s_snapshot_cno = 0;
 989
 990                 err = nilfs_attach_segment_constructor(sbi);
 991                 if (err)
 992                         goto rw_remount_failed;
 993
 994                 down_write(&nilfs->ns_sem);
 995                 nilfs_setup_super(sbi);
 996                 nilfs->ns_current = sbi;
 997                 up_write(&nilfs->ns_sem);
 998
 999                 up(&sb->s_bdev->bd_mount_sem);
1000         }
1001  out:
1002         unlock_kernel();
1003         return 0;
1004
1005  rw_remount_failed:
1006         up(&sb->s_bdev->bd_mount_sem);
1007  restore_opts:
1008         sb->s_flags = old_sb_flags;
1009         sbi->s_mount_opt = old_opts.mount_opt;
1010         sbi->s_snapshot_cno = old_opts.snapshot_cno;
1011         unlock_kernel();
1012         return err;
1013 }
1014
1015 struct nilfs_super_data {
1016         struct block_device *bdev;
1017         __u64 cno;
1018         int flags;
1019 };
1020
1021 /**
1022  * nilfs_identify - pre-read mount options needed to identify mount instance
1023  * @data: mount options
1024  * @sd: nilfs_super_data
1025  */
1026 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1027 {
1028         char *p, *options = data;
1029         substring_t args[MAX_OPT_ARGS];
1030         int option, token;
1031         int ret = 0;
1032
1033         do {
1034                 p = strsep(&options, ",");
1035                 if (p != NULL && *p) {
1036                         token = match_token(p, tokens, args);
1037                         if (token == Opt_snapshot) {
1038                                 if (!(sd->flags & MS_RDONLY))
1039                                         ret++;
1040                                 else {
1041                                         ret = match_int(&args[0], &option);
1042                                         if (!ret) {
1043                                                 if (option > 0)
1044                                                         sd->cno = option;
1045                                                 else
1046                                                         ret++;
1047                                         }
1048                                 }
1049                         }
1050                         if (ret)
1051                                 printk(KERN_ERR
1052                                        "NILFS: invalid mount option: %s\n", p);
1053                 }
1054                 if (!options)
1055                         break;
1056                 BUG_ON(options == data);
1057                 *(options - 1) = ',';
1058         } while (!ret);
1059         return ret;
1060 }
1061
1062 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1063 {
1064         struct nilfs_super_data *sd = data;
1065
1066         s->s_bdev = sd->bdev;
1067         s->s_dev = s->s_bdev->bd_dev;
1068         return 0;
1069 }
1070
1071 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1072 {
1073         struct nilfs_super_data *sd = data;
1074         int ret;
1075
1076         if (s->s_bdev != sd->bdev)
1077                 return 0;
1078
1079         if (!((s->s_flags | sd->flags) & MS_RDONLY))
1080                 return 1; /* Reuse an old R/W-mode super_block */
1081
1082         if (s->s_flags & sd->flags & MS_RDONLY) {
1083                 if (down_read_trylock(&s->s_umount)) {
1084                         ret = s->s_root &&
1085                                 (sd->cno == NILFS_SB(s)->s_snapshot_cno);
1086                         up_read(&s->s_umount);
1087                         /*
1088                          * This path is locked with sb_lock by sget().
1089                          * So, drop_super() causes deadlock.
1090                          */
1091                         return ret;
1092                 }
1093         }
1094         return 0;
1095 }
1096
1097 static int
1098 nilfs_get_sb(struct file_system_type *fs_type, int flags,
1099              const char *dev_name, void *data, struct vfsmount *mnt)
1100 {
1101         struct nilfs_super_data sd;
1102         struct super_block *s;
1103         struct the_nilfs *nilfs;
1104         int err, need_to_close = 1;
1105
1106         sd.bdev = open_bdev_exclusive(dev_name, flags, fs_type);
1107         if (IS_ERR(sd.bdev))
1108                 return PTR_ERR(sd.bdev);
1109
1110         /*
1111          * To get mount instance using sget() vfs-routine, NILFS needs
1112          * much more information than normal filesystems to identify mount
1113          * instance.  For snapshot mounts, not only a mount type (ro-mount
1114          * or rw-mount) but also a checkpoint number is required.
1115          * The results are passed in sget() using nilfs_super_data.
1116          */
1117         sd.cno = 0;
1118         sd.flags = flags;
1119         if (nilfs_identify((char *)data, &sd)) {
1120                 err = -EINVAL;
1121                 goto failed;
1122         }
1123
1124         nilfs = find_or_create_nilfs(sd.bdev);
1125         if (!nilfs) {
1126                 err = -ENOMEM;
1127                 goto failed;
1128         }
1129
1130         down(&sd.bdev->bd_mount_sem);
1131
1132         if (!sd.cno) {
1133                 /*
1134                  * Check if an exclusive mount exists or not.
1135                  * Snapshot mounts coexist with a current mount
1136                  * (i.e. rw-mount or ro-mount), whereas rw-mount and
1137                  * ro-mount are mutually exclusive.
1138                  */
1139                 down_read(&nilfs->ns_sem);
1140                 if (nilfs->ns_current &&
1141                     ((nilfs->ns_current->s_super->s_flags ^ flags)
1142                      & MS_RDONLY)) {
1143                         up_read(&nilfs->ns_sem);
1144                         err = -EBUSY;
1145                         goto failed_unlock;
1146                 }
1147                 up_read(&nilfs->ns_sem);
1148         }
1149
1150         /*
1151          * Search specified snapshot or R/W mode super_block
1152          */
1153         if (!sd.cno)
1154                 /* trying to get the latest checkpoint.  */
1155                 sd.cno = nilfs_last_cno(nilfs);
1156
1157         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, &sd);
1158         if (IS_ERR(s)) {
1159                 err = PTR_ERR(s);
1160                 goto failed_unlock;
1161         }
1162
1163         if (!s->s_root) {
1164                 char b[BDEVNAME_SIZE];
1165
1166                 /* New superblock instance created */
1167                 s->s_flags = flags;
1168                 strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
1169                 sb_set_blocksize(s, block_size(sd.bdev));
1170
1171                 err = nilfs_fill_super(s, data, flags & MS_VERBOSE, nilfs);
1172                 if (err)
1173                         goto cancel_new;
1174
1175                 s->s_flags |= MS_ACTIVE;
1176                 need_to_close = 0;
1177         }
1178
1179         up(&sd.bdev->bd_mount_sem);
1180         put_nilfs(nilfs);
1181         if (need_to_close)
1182                 close_bdev_exclusive(sd.bdev, flags);
1183         simple_set_mnt(mnt, s);
1184         return 0;
1185
1186  failed_unlock:
1187         up(&sd.bdev->bd_mount_sem);
1188         put_nilfs(nilfs);
1189  failed:
1190         close_bdev_exclusive(sd.bdev, flags);
1191
1192         return err;
1193
1194  cancel_new:
1195         /* Abandoning the newly allocated superblock */
1196         up(&sd.bdev->bd_mount_sem);
1197         put_nilfs(nilfs);
1198         up_write(&s->s_umount);
1199         deactivate_super(s);
1200         /*
1201          * deactivate_super() invokes close_bdev_exclusive().
1202          * We must finish all post-cleaning before this call;
1203          * put_nilfs() and unlocking bd_mount_sem need the block device.
1204          */
1205         return err;
1206 }
1207
1208 struct file_system_type nilfs_fs_type = {
1209         .owner    = THIS_MODULE,
1210         .name     = "nilfs2",
1211         .get_sb   = nilfs_get_sb,
1212         .kill_sb  = kill_block_super,
1213         .fs_flags = FS_REQUIRES_DEV,
1214 };
1215
1216 static int __init init_nilfs_fs(void)
1217 {
1218         int err;
1219
1220         err = nilfs_init_inode_cache();
1221         if (err)
1222                 goto failed;
1223
1224         err = nilfs_init_transaction_cache();
1225         if (err)
1226                 goto failed_inode_cache;
1227
1228         err = nilfs_init_segbuf_cache();
1229         if (err)
1230                 goto failed_transaction_cache;
1231
1232         err = nilfs_btree_path_cache_init();
1233         if (err)
1234                 goto failed_segbuf_cache;
1235
1236         err = register_filesystem(&nilfs_fs_type);
1237         if (err)
1238                 goto failed_btree_path_cache;
1239
1240         return 0;
1241
1242  failed_btree_path_cache:
1243         nilfs_btree_path_cache_destroy();
1244
1245  failed_segbuf_cache:
1246         nilfs_destroy_segbuf_cache();
1247
1248  failed_transaction_cache:
1249         nilfs_destroy_transaction_cache();
1250
1251  failed_inode_cache:
1252         nilfs_destroy_inode_cache();
1253
1254  failed:
1255         return err;
1256 }
1257
1258 static void __exit exit_nilfs_fs(void)
1259 {
1260         nilfs_destroy_segbuf_cache();
1261         nilfs_destroy_transaction_cache();
1262         nilfs_destroy_inode_cache();
1263         nilfs_btree_path_cache_destroy();
1264         unregister_filesystem(&nilfs_fs_type);
1265 }
1266
1267 module_init(init_nilfs_fs)
1268 module_exit(exit_nilfs_fs)