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