fs/nilfs2/super.c

   1 /*
   2  * super.c - NILFS module and super block management.
   3  *
   4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  * Written by Ryusuke Konishi <ryusuke@osrg.net>
  21  */
  22 /*
  23  *  linux/fs/ext2/super.c
  24  *
  25  * Copyright (C) 1992, 1993, 1994, 1995
  26  * Remy Card (card@masi.ibp.fr)
  27  * Laboratoire MASI - Institut Blaise Pascal
  28  * Universite Pierre et Marie Curie (Paris VI)
  29  *
  30  *  from
  31  *
  32  *  linux/fs/minix/inode.c
  33  *
  34  *  Copyright (C) 1991, 1992  Linus Torvalds
  35  *
  36  *  Big-endian to little-endian byte-swapping/bitmaps by
  37  *        David S. Miller (davem@caip.rutgers.edu), 1995
  38  */
  39
  40 #include <linux/module.h>
  41 #include <linux/string.h>
  42 #include <linux/slab.h>
  43 #include <linux/init.h>
  44 #include <linux/blkdev.h>
  45 #include <linux/parser.h>
  46 #include <linux/random.h>
  47 #include <linux/crc32.h>
  48 #include <linux/vfs.h>
  49 #include <linux/writeback.h>
  50 #include <linux/kobject.h>
  51 #include <linux/seq_file.h>
  52 #include <linux/mount.h>
  53 #include "nilfs.h"
  54 #include "export.h"
  55 #include "mdt.h"
  56 #include "alloc.h"
  57 #include "btree.h"
  58 #include "btnode.h"
  59 #include "page.h"
  60 #include "cpfile.h"
  61 #include "ifile.h"
  62 #include "dat.h"
  63 #include "segment.h"
  64 #include "segbuf.h"
  65
  66 MODULE_AUTHOR("NTT Corp.");
  67 MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
  68                    "(NILFS)");
  69 MODULE_LICENSE("GPL");
  70
  71 struct kmem_cache *nilfs_inode_cachep;
  72 struct kmem_cache *nilfs_transaction_cachep;
  73 struct kmem_cache *nilfs_segbuf_cachep;
  74 struct kmem_cache *nilfs_btree_path_cache;
  75
  76 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
  77
  78 static void nilfs_set_error(struct nilfs_sb_info *sbi)
  79 {
  80         struct the_nilfs *nilfs = sbi->s_nilfs;
  81         struct nilfs_super_block **sbp;
  82
  83         down_write(&nilfs->ns_sem);
  84         if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
  85                 nilfs->ns_mount_state |= NILFS_ERROR_FS;
  86                 sbp = nilfs_prepare_super(sbi, 0);
  87                 if (likely(sbp)) {
  88                         sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  89                         if (sbp[1])
  90                                 sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  91                         nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
  92                 }
  93         }
  94         up_write(&nilfs->ns_sem);
  95 }
  96
  97 /**
  98  * nilfs_error() - report failure condition on a filesystem
  99  *
 100  * nilfs_error() sets an ERROR_FS flag on the superblock as well as
 101  * reporting an error message.  It should be called when NILFS detects
 102  * incoherences or defects of meta data on disk.  As for sustainable
 103  * errors such as a single-shot I/O error, nilfs_warning() or the printk()
 104  * function should be used instead.
 105  *
 106  * The segment constructor must not call this function because it can
 107  * kill itself.
 108  */
 109 void nilfs_error(struct super_block *sb, const char *function,
 110                  const char *fmt, ...)
 111 {
 112         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 113         va_list args;
 114
 115         va_start(args, fmt);
 116         printk(KERN_CRIT "NILFS error (device %s): %s: ", sb->s_id, function);
 117         vprintk(fmt, args);
 118         printk("\n");
 119         va_end(args);
 120
 121         if (!(sb->s_flags & MS_RDONLY)) {
 122                 nilfs_set_error(sbi);
 123
 124                 if (nilfs_test_opt(sbi, ERRORS_RO)) {
 125                         printk(KERN_CRIT "Remounting filesystem read-only\n");
 126                         sb->s_flags |= MS_RDONLY;
 127                 }
 128         }
 129
 130         if (nilfs_test_opt(sbi, ERRORS_PANIC))
 131                 panic("NILFS (device %s): panic forced after error\n",
 132                       sb->s_id);
 133 }
 134
 135 void nilfs_warning(struct super_block *sb, const char *function,
 136                    const char *fmt, ...)
 137 {
 138         va_list args;
 139
 140         va_start(args, fmt);
 141         printk(KERN_WARNING "NILFS warning (device %s): %s: ",
 142                sb->s_id, function);
 143         vprintk(fmt, args);
 144         printk("\n");
 145         va_end(args);
 146 }
 147
 148
 149 struct inode *nilfs_alloc_inode_common(struct the_nilfs *nilfs)
 150 {
 151         struct nilfs_inode_info *ii;
 152
 153         ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
 154         if (!ii)
 155                 return NULL;
 156         ii->i_bh = NULL;
 157         ii->i_state = 0;
 158         ii->i_cno = 0;
 159         ii->vfs_inode.i_version = 1;
 160         nilfs_btnode_cache_init(&ii->i_btnode_cache, nilfs->ns_bdi);
 161         return &ii->vfs_inode;
 162 }
 163
 164 struct inode *nilfs_alloc_inode(struct super_block *sb)
 165 {
 166         return nilfs_alloc_inode_common(NILFS_SB(sb)->s_nilfs);
 167 }
 168
 169 void nilfs_destroy_inode(struct inode *inode)
 170 {
 171         struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
 172
 173         if (mdi) {
 174                 kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
 175                 kfree(mdi);
 176         }
 177         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 178 }
 179
 180 static int nilfs_sync_super(struct nilfs_sb_info *sbi, int flag)
 181 {
 182         struct the_nilfs *nilfs = sbi->s_nilfs;
 183         int err;
 184
 185  retry:
 186         set_buffer_dirty(nilfs->ns_sbh[0]);
 187
 188         if (nilfs_test_opt(sbi, BARRIER)) {
 189                 err = __sync_dirty_buffer(nilfs->ns_sbh[0],
 190                                           WRITE_SYNC | WRITE_BARRIER);
 191                 if (err == -EOPNOTSUPP) {
 192                         nilfs_warning(sbi->s_super, __func__,
 193                                       "barrier-based sync failed. "
 194                                       "disabling barriers\n");
 195                         nilfs_clear_opt(sbi, BARRIER);
 196                         goto retry;
 197                 }
 198         } else {
 199                 err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 200         }
 201
 202         if (unlikely(err)) {
 203                 printk(KERN_ERR
 204                        "NILFS: unable to write superblock (err=%d)\n", err);
 205                 if (err == -EIO && nilfs->ns_sbh[1]) {
 206                         /*
 207                          * sbp[0] points to newer log than sbp[1],
 208                          * so copy sbp[0] to sbp[1] to take over sbp[0].
 209                          */
 210                         memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
 211                                nilfs->ns_sbsize);
 212                         nilfs_fall_back_super_block(nilfs);
 213                         goto retry;
 214                 }
 215         } else {
 216                 struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 217
 218                 nilfs->ns_sbwcount++;
 219
 220                 /*
 221                  * The latest segment becomes trailable from the position
 222                  * written in superblock.
 223                  */
 224                 clear_nilfs_discontinued(nilfs);
 225
 226                 /* update GC protection for recent segments */
 227                 if (nilfs->ns_sbh[1]) {
 228                         if (flag == NILFS_SB_COMMIT_ALL) {
 229                                 set_buffer_dirty(nilfs->ns_sbh[1]);
 230                                 if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
 231                                         goto out;
 232                         }
 233                         if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
 234                             le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
 235                                 sbp = nilfs->ns_sbp[1];
 236                 }
 237
 238                 spin_lock(&nilfs->ns_last_segment_lock);
 239                 nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
 240                 spin_unlock(&nilfs->ns_last_segment_lock);
 241         }
 242  out:
 243         return err;
 244 }
 245
 246 void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
 247                           struct the_nilfs *nilfs)
 248 {
 249         sector_t nfreeblocks;
 250
 251         /* nilfs->ns_sem must be locked by the caller. */
 252         nilfs_count_free_blocks(nilfs, &nfreeblocks);
 253         sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
 254
 255         spin_lock(&nilfs->ns_last_segment_lock);
 256         sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
 257         sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
 258         sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
 259         spin_unlock(&nilfs->ns_last_segment_lock);
 260 }
 261
 262 struct nilfs_super_block **nilfs_prepare_super(struct nilfs_sb_info *sbi,
 263                                                int flip)
 264 {
 265         struct the_nilfs *nilfs = sbi->s_nilfs;
 266         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 267
 268         /* nilfs->ns_sem must be locked by the caller. */
 269         if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 270                 if (sbp[1] &&
 271                     sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
 272                         memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
 273                 } else {
 274                         printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
 275                                sbi->s_super->s_id);
 276                         return NULL;
 277                 }
 278         } else if (sbp[1] &&
 279                    sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 280                         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 281         }
 282
 283         if (flip && sbp[1])
 284                 nilfs_swap_super_block(nilfs);
 285
 286         return sbp;
 287 }
 288
 289 int nilfs_commit_super(struct nilfs_sb_info *sbi, int flag)
 290 {
 291         struct the_nilfs *nilfs = sbi->s_nilfs;
 292         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 293         time_t t;
 294
 295         /* nilfs->ns_sem must be locked by the caller. */
 296         t = get_seconds();
 297         nilfs->ns_sbwtime = t;
 298         sbp[0]->s_wtime = cpu_to_le64(t);
 299         sbp[0]->s_sum = 0;
 300         sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 301                                              (unsigned char *)sbp[0],
 302                                              nilfs->ns_sbsize));
 303         if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
 304                 sbp[1]->s_wtime = sbp[0]->s_wtime;
 305                 sbp[1]->s_sum = 0;
 306                 sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 307                                             (unsigned char *)sbp[1],
 308                                             nilfs->ns_sbsize));
 309         }
 310         clear_nilfs_sb_dirty(nilfs);
 311         return nilfs_sync_super(sbi, flag);
 312 }
 313
 314 /**
 315  * nilfs_cleanup_super() - write filesystem state for cleanup
 316  * @sbi: nilfs_sb_info to be unmounted or degraded to read-only
 317  *
 318  * This function restores state flags in the on-disk super block.
 319  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
 320  * filesystem was not clean previously.
 321  */
 322 int nilfs_cleanup_super(struct nilfs_sb_info *sbi)
 323 {
 324         struct nilfs_super_block **sbp;
 325         int flag = NILFS_SB_COMMIT;
 326         int ret = -EIO;
 327
 328         sbp = nilfs_prepare_super(sbi, 0);
 329         if (sbp) {
 330                 sbp[0]->s_state = cpu_to_le16(sbi->s_nilfs->ns_mount_state);
 331                 nilfs_set_log_cursor(sbp[0], sbi->s_nilfs);
 332                 if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
 333                         /*
 334                          * make the "clean" flag also to the opposite
 335                          * super block if both super blocks point to
 336                          * the same checkpoint.
 337                          */
 338                         sbp[1]->s_state = sbp[0]->s_state;
 339                         flag = NILFS_SB_COMMIT_ALL;
 340                 }
 341                 ret = nilfs_commit_super(sbi, flag);
 342         }
 343         return ret;
 344 }
 345
 346 static void nilfs_put_super(struct super_block *sb)
 347 {
 348         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 349         struct the_nilfs *nilfs = sbi->s_nilfs;
 350
 351         nilfs_detach_segment_constructor(sbi);
 352
 353         if (!(sb->s_flags & MS_RDONLY)) {
 354                 down_write(&nilfs->ns_sem);
 355                 nilfs_cleanup_super(sbi);
 356                 up_write(&nilfs->ns_sem);
 357         }
 358
 359         destroy_nilfs(nilfs);
 360         sbi->s_super = NULL;
 361         sb->s_fs_info = NULL;
 362         kfree(sbi);
 363 }
 364
 365 static int nilfs_sync_fs(struct super_block *sb, int wait)
 366 {
 367         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 368         struct the_nilfs *nilfs = sbi->s_nilfs;
 369         struct nilfs_super_block **sbp;
 370         int err = 0;
 371
 372         /* This function is called when super block should be written back */
 373         if (wait)
 374                 err = nilfs_construct_segment(sb);
 375
 376         down_write(&nilfs->ns_sem);
 377         if (nilfs_sb_dirty(nilfs)) {
 378                 sbp = nilfs_prepare_super(sbi, nilfs_sb_will_flip(nilfs));
 379                 if (likely(sbp)) {
 380                         nilfs_set_log_cursor(sbp[0], nilfs);
 381                         nilfs_commit_super(sbi, NILFS_SB_COMMIT);
 382                 }
 383         }
 384         up_write(&nilfs->ns_sem);
 385
 386         return err;
 387 }
 388
 389 int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno, int curr_mnt,
 390                             struct nilfs_root **rootp)
 391 {
 392         struct the_nilfs *nilfs = sbi->s_nilfs;
 393         struct nilfs_root *root;
 394         struct nilfs_checkpoint *raw_cp;
 395         struct buffer_head *bh_cp;
 396         int err = -ENOMEM;
 397
 398         root = nilfs_find_or_create_root(
 399                 nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
 400         if (!root)
 401                 return err;
 402
 403         if (root->ifile)
 404                 goto reuse; /* already attached checkpoint */
 405
 406         root->ifile = nilfs_ifile_new(sbi, nilfs->ns_inode_size);
 407         if (!root->ifile)
 408                 goto failed;
 409
 410         down_read(&nilfs->ns_segctor_sem);
 411         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 412                                           &bh_cp);
 413         up_read(&nilfs->ns_segctor_sem);
 414         if (unlikely(err)) {
 415                 if (err == -ENOENT || err == -EINVAL) {
 416                         printk(KERN_ERR
 417                                "NILFS: Invalid checkpoint "
 418                                "(checkpoint number=%llu)\n",
 419                                (unsigned long long)cno);
 420                         err = -EINVAL;
 421                 }
 422                 goto failed;
 423         }
 424         err = nilfs_read_inode_common(root->ifile, &raw_cp->cp_ifile_inode);
 425         if (unlikely(err))
 426                 goto failed_bh;
 427
 428         atomic_set(&root->inodes_count, le64_to_cpu(raw_cp->cp_inodes_count));
 429         atomic_set(&root->blocks_count, le64_to_cpu(raw_cp->cp_blocks_count));
 430
 431         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 432
 433  reuse:
 434         *rootp = root;
 435         return 0;
 436
 437  failed_bh:
 438         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 439  failed:
 440         nilfs_put_root(root);
 441
 442         return err;
 443 }
 444
 445 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 446 {
 447         struct super_block *sb = dentry->d_sb;
 448         struct nilfs_root *root = NILFS_I(dentry->d_inode)->i_root;
 449         struct the_nilfs *nilfs = root->nilfs;
 450         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 451         unsigned long long blocks;
 452         unsigned long overhead;
 453         unsigned long nrsvblocks;
 454         sector_t nfreeblocks;
 455         int err;
 456
 457         /*
 458          * Compute all of the segment blocks
 459          *
 460          * The blocks before first segment and after last segment
 461          * are excluded.
 462          */
 463         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 464                 - nilfs->ns_first_data_block;
 465         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 466
 467         /*
 468          * Compute the overhead
 469          *
 470          * When distributing meta data blocks outside segment structure,
 471          * We must count them as the overhead.
 472          */
 473         overhead = 0;
 474
 475         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 476         if (unlikely(err))
 477                 return err;
 478
 479         buf->f_type = NILFS_SUPER_MAGIC;
 480         buf->f_bsize = sb->s_blocksize;
 481         buf->f_blocks = blocks - overhead;
 482         buf->f_bfree = nfreeblocks;
 483         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 484                 (buf->f_bfree - nrsvblocks) : 0;
 485         buf->f_files = atomic_read(&root->inodes_count);
 486         buf->f_ffree = 0; /* nilfs_count_free_inodes(sb); */
 487         buf->f_namelen = NILFS_NAME_LEN;
 488         buf->f_fsid.val[0] = (u32)id;
 489         buf->f_fsid.val[1] = (u32)(id >> 32);
 490
 491         return 0;
 492 }
 493
 494 static int nilfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 495 {
 496         struct super_block *sb = vfs->mnt_sb;
 497         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 498         struct nilfs_root *root = NILFS_I(vfs->mnt_root->d_inode)->i_root;
 499
 500         if (!nilfs_test_opt(sbi, BARRIER))
 501                 seq_puts(seq, ",nobarrier");
 502         if (root->cno != NILFS_CPTREE_CURRENT_CNO)
 503                 seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
 504         if (nilfs_test_opt(sbi, ERRORS_PANIC))
 505                 seq_puts(seq, ",errors=panic");
 506         if (nilfs_test_opt(sbi, ERRORS_CONT))
 507                 seq_puts(seq, ",errors=continue");
 508         if (nilfs_test_opt(sbi, STRICT_ORDER))
 509                 seq_puts(seq, ",order=strict");
 510         if (nilfs_test_opt(sbi, NORECOVERY))
 511                 seq_puts(seq, ",norecovery");
 512         if (nilfs_test_opt(sbi, DISCARD))
 513                 seq_puts(seq, ",discard");
 514
 515         return 0;
 516 }
 517
 518 static const struct super_operations nilfs_sops = {
 519         .alloc_inode    = nilfs_alloc_inode,
 520         .destroy_inode  = nilfs_destroy_inode,
 521         .dirty_inode    = nilfs_dirty_inode,
 522         /* .write_inode    = nilfs_write_inode, */
 523         /* .put_inode      = nilfs_put_inode, */
 524         /* .drop_inode    = nilfs_drop_inode, */
 525         .evict_inode    = nilfs_evict_inode,
 526         .put_super      = nilfs_put_super,
 527         /* .write_super    = nilfs_write_super, */
 528         .sync_fs        = nilfs_sync_fs,
 529         /* .write_super_lockfs */
 530         /* .unlockfs */
 531         .statfs         = nilfs_statfs,
 532         .remount_fs     = nilfs_remount,
 533         /* .umount_begin */
 534         .show_options = nilfs_show_options
 535 };
 536
 537 enum {
 538         Opt_err_cont, Opt_err_panic, Opt_err_ro,
 539         Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
 540         Opt_discard, Opt_nodiscard, Opt_err,
 541 };
 542
 543 static match_table_t tokens = {
 544         {Opt_err_cont, "errors=continue"},
 545         {Opt_err_panic, "errors=panic"},
 546         {Opt_err_ro, "errors=remount-ro"},
 547         {Opt_barrier, "barrier"},
 548         {Opt_nobarrier, "nobarrier"},
 549         {Opt_snapshot, "cp=%u"},
 550         {Opt_order, "order=%s"},
 551         {Opt_norecovery, "norecovery"},
 552         {Opt_discard, "discard"},
 553         {Opt_nodiscard, "nodiscard"},
 554         {Opt_err, NULL}
 555 };
 556
 557 static int parse_options(char *options, struct super_block *sb, int is_remount)
 558 {
 559         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 560         char *p;
 561         substring_t args[MAX_OPT_ARGS];
 562         int option;
 563
 564         if (!options)
 565                 return 1;
 566
 567         while ((p = strsep(&options, ",")) != NULL) {
 568                 int token;
 569                 if (!*p)
 570                         continue;
 571
 572                 token = match_token(p, tokens, args);
 573                 switch (token) {
 574                 case Opt_barrier:
 575                         nilfs_set_opt(sbi, BARRIER);
 576                         break;
 577                 case Opt_nobarrier:
 578                         nilfs_clear_opt(sbi, BARRIER);
 579                         break;
 580                 case Opt_order:
 581                         if (strcmp(args[0].from, "relaxed") == 0)
 582                                 /* Ordered data semantics */
 583                                 nilfs_clear_opt(sbi, STRICT_ORDER);
 584                         else if (strcmp(args[0].from, "strict") == 0)
 585                                 /* Strict in-order semantics */
 586                                 nilfs_set_opt(sbi, STRICT_ORDER);
 587                         else
 588                                 return 0;
 589                         break;
 590                 case Opt_err_panic:
 591                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_PANIC);
 592                         break;
 593                 case Opt_err_ro:
 594                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_RO);
 595                         break;
 596                 case Opt_err_cont:
 597                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_CONT);
 598                         break;
 599                 case Opt_snapshot:
 600                         if (match_int(&args[0], &option) || option <= 0)
 601                                 return 0;
 602                         if (is_remount) {
 603                                 printk(KERN_ERR
 604                                        "NILFS: \"%s\" option is invalid "
 605                                        "for remount.\n", p);
 606                                 return 0;
 607                         }
 608                         break;
 609                 case Opt_norecovery:
 610                         nilfs_set_opt(sbi, NORECOVERY);
 611                         break;
 612                 case Opt_discard:
 613                         nilfs_set_opt(sbi, DISCARD);
 614                         break;
 615                 case Opt_nodiscard:
 616                         nilfs_clear_opt(sbi, DISCARD);
 617                         break;
 618                 default:
 619                         printk(KERN_ERR
 620                                "NILFS: Unrecognized mount option \"%s\"\n", p);
 621                         return 0;
 622                 }
 623         }
 624         return 1;
 625 }
 626
 627 static inline void
 628 nilfs_set_default_options(struct nilfs_sb_info *sbi,
 629                           struct nilfs_super_block *sbp)
 630 {
 631         sbi->s_mount_opt =
 632                 NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
 633 }
 634
 635 static int nilfs_setup_super(struct nilfs_sb_info *sbi)
 636 {
 637         struct the_nilfs *nilfs = sbi->s_nilfs;
 638         struct nilfs_super_block **sbp;
 639         int max_mnt_count;
 640         int mnt_count;
 641
 642         /* nilfs->ns_sem must be locked by the caller. */
 643         sbp = nilfs_prepare_super(sbi, 0);
 644         if (!sbp)
 645                 return -EIO;
 646
 647         max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
 648         mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
 649
 650         if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 651                 printk(KERN_WARNING
 652                        "NILFS warning: mounting fs with errors\n");
 653 #if 0
 654         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 655                 printk(KERN_WARNING
 656                        "NILFS warning: maximal mount count reached\n");
 657 #endif
 658         }
 659         if (!max_mnt_count)
 660                 sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 661
 662         sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
 663         sbp[0]->s_state =
 664                 cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
 665         sbp[0]->s_mtime = cpu_to_le64(get_seconds());
 666         /* synchronize sbp[1] with sbp[0] */
 667         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 668         return nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
 669 }
 670
 671 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 672                                                  u64 pos, int blocksize,
 673                                                  struct buffer_head **pbh)
 674 {
 675         unsigned long long sb_index = pos;
 676         unsigned long offset;
 677
 678         offset = do_div(sb_index, blocksize);
 679         *pbh = sb_bread(sb, sb_index);
 680         if (!*pbh)
 681                 return NULL;
 682         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 683 }
 684
 685 int nilfs_store_magic_and_option(struct super_block *sb,
 686                                  struct nilfs_super_block *sbp,
 687                                  char *data)
 688 {
 689         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 690
 691         sb->s_magic = le16_to_cpu(sbp->s_magic);
 692
 693         /* FS independent flags */
 694 #ifdef NILFS_ATIME_DISABLE
 695         sb->s_flags |= MS_NOATIME;
 696 #endif
 697
 698         nilfs_set_default_options(sbi, sbp);
 699
 700         sbi->s_resuid = le16_to_cpu(sbp->s_def_resuid);
 701         sbi->s_resgid = le16_to_cpu(sbp->s_def_resgid);
 702         sbi->s_interval = le32_to_cpu(sbp->s_c_interval);
 703         sbi->s_watermark = le32_to_cpu(sbp->s_c_block_max);
 704
 705         return !parse_options(data, sb, 0) ? -EINVAL : 0 ;
 706 }
 707
 708 int nilfs_check_feature_compatibility(struct super_block *sb,
 709                                       struct nilfs_super_block *sbp)
 710 {
 711         __u64 features;
 712
 713         features = le64_to_cpu(sbp->s_feature_incompat) &
 714                 ~NILFS_FEATURE_INCOMPAT_SUPP;
 715         if (features) {
 716                 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
 717                        "optional features (%llx)\n",
 718                        (unsigned long long)features);
 719                 return -EINVAL;
 720         }
 721         features = le64_to_cpu(sbp->s_feature_compat_ro) &
 722                 ~NILFS_FEATURE_COMPAT_RO_SUPP;
 723         if (!(sb->s_flags & MS_RDONLY) && features) {
 724                 printk(KERN_ERR "NILFS: couldn't mount RDWR because of "
 725                        "unsupported optional features (%llx)\n",
 726                        (unsigned long long)features);
 727                 return -EINVAL;
 728         }
 729         return 0;
 730 }
 731
 732 static int nilfs_get_root_dentry(struct super_block *sb,
 733                                  struct nilfs_root *root,
 734                                  struct dentry **root_dentry)
 735 {
 736         struct inode *inode;
 737         struct dentry *dentry;
 738         int ret = 0;
 739
 740         inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
 741         if (IS_ERR(inode)) {
 742                 printk(KERN_ERR "NILFS: get root inode failed\n");
 743                 ret = PTR_ERR(inode);
 744                 goto out;
 745         }
 746         if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
 747                 iput(inode);
 748                 printk(KERN_ERR "NILFS: corrupt root inode.\n");
 749                 ret = -EINVAL;
 750                 goto out;
 751         }
 752
 753         if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
 754                 dentry = d_find_alias(inode);
 755                 if (!dentry) {
 756                         dentry = d_alloc_root(inode);
 757                         if (!dentry) {
 758                                 iput(inode);
 759                                 ret = -ENOMEM;
 760                                 goto failed_dentry;
 761                         }
 762                 } else {
 763                         iput(inode);
 764                 }
 765         } else {
 766                 dentry = d_obtain_alias(inode);
 767                 if (IS_ERR(dentry)) {
 768                         ret = PTR_ERR(dentry);
 769                         goto failed_dentry;
 770                 }
 771         }
 772         *root_dentry = dentry;
 773  out:
 774         return ret;
 775
 776  failed_dentry:
 777         printk(KERN_ERR "NILFS: get root dentry failed\n");
 778         goto out;
 779 }
 780
 781 static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 782                                  struct dentry **root_dentry)
 783 {
 784         struct the_nilfs *nilfs = NILFS_SB(s)->s_nilfs;
 785         struct nilfs_root *root;
 786         int ret;
 787
 788         down_read(&nilfs->ns_segctor_sem);
 789         ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
 790         up_read(&nilfs->ns_segctor_sem);
 791         if (ret < 0) {
 792                 ret = (ret == -ENOENT) ? -EINVAL : ret;
 793                 goto out;
 794         } else if (!ret) {
 795                 printk(KERN_ERR "NILFS: The specified checkpoint is "
 796                        "not a snapshot (checkpoint number=%llu).\n",
 797                        (unsigned long long)cno);
 798                 ret = -EINVAL;
 799                 goto out;
 800         }
 801
 802         ret = nilfs_attach_checkpoint(NILFS_SB(s), cno, false, &root);
 803         if (ret) {
 804                 printk(KERN_ERR "NILFS: error loading snapshot "
 805                        "(checkpoint number=%llu).\n",
 806                (unsigned long long)cno);
 807                 goto out;
 808         }
 809         ret = nilfs_get_root_dentry(s, root, root_dentry);
 810         nilfs_put_root(root);
 811  out:
 812         return ret;
 813 }
 814
 815 static int nilfs_tree_was_touched(struct dentry *root_dentry)
 816 {
 817         return atomic_read(&root_dentry->d_count) > 1;
 818 }
 819
 820 /**
 821  * nilfs_try_to_shrink_tree() - try to shrink dentries of a checkpoint
 822  * @root_dentry: root dentry of the tree to be shrunk
 823  *
 824  * This function returns true if the tree was in-use.
 825  */
 826 static int nilfs_try_to_shrink_tree(struct dentry *root_dentry)
 827 {
 828         if (have_submounts(root_dentry))
 829                 return true;
 830         shrink_dcache_parent(root_dentry);
 831         return nilfs_tree_was_touched(root_dentry);
 832 }
 833
 834 /**
 835  * nilfs_fill_super() - initialize a super block instance
 836  * @sb: super_block
 837  * @data: mount options
 838  * @silent: silent mode flag
 839  *
 840  * This function is called exclusively by nilfs->ns_mount_mutex.
 841  * So, the recovery process is protected from other simultaneous mounts.
 842  */
 843 static int
 844 nilfs_fill_super(struct super_block *sb, void *data, int silent)
 845 {
 846         struct the_nilfs *nilfs;
 847         struct nilfs_sb_info *sbi;
 848         struct nilfs_root *fsroot;
 849         __u64 cno;
 850         int err;
 851
 852         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 853         if (!sbi)
 854                 return -ENOMEM;
 855
 856         sb->s_fs_info = sbi;
 857         sbi->s_super = sb;
 858
 859         nilfs = alloc_nilfs(sb->s_bdev);
 860         if (!nilfs) {
 861                 err = -ENOMEM;
 862                 goto failed_sbi;
 863         }
 864         sbi->s_nilfs = nilfs;
 865
 866         err = init_nilfs(nilfs, sbi, (char *)data);
 867         if (err)
 868                 goto failed_nilfs;
 869
 870         spin_lock_init(&sbi->s_inode_lock);
 871         INIT_LIST_HEAD(&sbi->s_dirty_files);
 872
 873         /*
 874          * Following initialization is overlapped because
 875          * nilfs_sb_info structure has been cleared at the beginning.
 876          * But we reserve them to keep our interest and make ready
 877          * for the future change.
 878          */
 879         get_random_bytes(&sbi->s_next_generation,
 880                          sizeof(sbi->s_next_generation));
 881         spin_lock_init(&sbi->s_next_gen_lock);
 882
 883         sb->s_op = &nilfs_sops;
 884         sb->s_export_op = &nilfs_export_ops;
 885         sb->s_root = NULL;
 886         sb->s_time_gran = 1;
 887         sb->s_bdi = nilfs->ns_bdi;
 888
 889         err = load_nilfs(nilfs, sbi);
 890         if (err)
 891                 goto failed_nilfs;
 892
 893         cno = nilfs_last_cno(nilfs);
 894         err = nilfs_attach_checkpoint(sbi, cno, true, &fsroot);
 895         if (err) {
 896                 printk(KERN_ERR "NILFS: error loading last checkpoint "
 897                        "(checkpoint number=%llu).\n", (unsigned long long)cno);
 898                 goto failed_nilfs;
 899         }
 900
 901         if (!(sb->s_flags & MS_RDONLY)) {
 902                 err = nilfs_attach_segment_constructor(sbi, fsroot);
 903                 if (err)
 904                         goto failed_checkpoint;
 905         }
 906
 907         err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
 908         if (err)
 909                 goto failed_segctor;
 910
 911         nilfs_put_root(fsroot);
 912
 913         if (!(sb->s_flags & MS_RDONLY)) {
 914                 down_write(&nilfs->ns_sem);
 915                 nilfs_setup_super(sbi);
 916                 up_write(&nilfs->ns_sem);
 917         }
 918
 919         return 0;
 920
 921  failed_segctor:
 922         nilfs_detach_segment_constructor(sbi);
 923
 924  failed_checkpoint:
 925         nilfs_put_root(fsroot);
 926
 927  failed_nilfs:
 928         destroy_nilfs(nilfs);
 929
 930  failed_sbi:
 931         sb->s_fs_info = NULL;
 932         kfree(sbi);
 933         return err;
 934 }
 935
 936 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
 937 {
 938         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 939         struct the_nilfs *nilfs = sbi->s_nilfs;
 940         unsigned long old_sb_flags;
 941         struct nilfs_mount_options old_opts;
 942         int err;
 943
 944         old_sb_flags = sb->s_flags;
 945         old_opts.mount_opt = sbi->s_mount_opt;
 946
 947         if (!parse_options(data, sb, 1)) {
 948                 err = -EINVAL;
 949                 goto restore_opts;
 950         }
 951         sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
 952
 953         err = -EINVAL;
 954
 955         if (!nilfs_valid_fs(nilfs)) {
 956                 printk(KERN_WARNING "NILFS (device %s): couldn't "
 957                        "remount because the filesystem is in an "
 958                        "incomplete recovery state.\n", sb->s_id);
 959                 goto restore_opts;
 960         }
 961
 962         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 963                 goto out;
 964         if (*flags & MS_RDONLY) {
 965                 /* Shutting down the segment constructor */
 966                 nilfs_detach_segment_constructor(sbi);
 967                 sb->s_flags |= MS_RDONLY;
 968
 969                 /*
 970                  * Remounting a valid RW partition RDONLY, so set
 971                  * the RDONLY flag and then mark the partition as valid again.
 972                  */
 973                 down_write(&nilfs->ns_sem);
 974                 nilfs_cleanup_super(sbi);
 975                 up_write(&nilfs->ns_sem);
 976         } else {
 977                 __u64 features;
 978                 struct nilfs_root *root;
 979
 980                 /*
 981                  * Mounting a RDONLY partition read-write, so reread and
 982                  * store the current valid flag.  (It may have been changed
 983                  * by fsck since we originally mounted the partition.)
 984                  */
 985                 down_read(&nilfs->ns_sem);
 986                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
 987                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
 988                 up_read(&nilfs->ns_sem);
 989                 if (features) {
 990                         printk(KERN_WARNING "NILFS (device %s): couldn't "
 991                                "remount RDWR because of unsupported optional "
 992                                "features (%llx)\n",
 993                                sb->s_id, (unsigned long long)features);
 994                         err = -EROFS;
 995                         goto restore_opts;
 996                 }
 997
 998                 sb->s_flags &= ~MS_RDONLY;
 999
1000                 root = NILFS_I(sb->s_root->d_inode)->i_root;
1001                 err = nilfs_attach_segment_constructor(sbi, root);
1002                 if (err)
1003                         goto restore_opts;
1004
1005                 down_write(&nilfs->ns_sem);
1006                 nilfs_setup_super(sbi);
1007                 up_write(&nilfs->ns_sem);
1008         }
1009  out:
1010         return 0;
1011
1012  restore_opts:
1013         sb->s_flags = old_sb_flags;
1014         sbi->s_mount_opt = old_opts.mount_opt;
1015         return err;
1016 }
1017
1018 struct nilfs_super_data {
1019         struct block_device *bdev;
1020         struct nilfs_sb_info *sbi;
1021         __u64 cno;
1022         int flags;
1023 };
1024
1025 /**
1026  * nilfs_identify - pre-read mount options needed to identify mount instance
1027  * @data: mount options
1028  * @sd: nilfs_super_data
1029  */
1030 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1031 {
1032         char *p, *options = data;
1033         substring_t args[MAX_OPT_ARGS];
1034         int option, token;
1035         int ret = 0;
1036
1037         do {
1038                 p = strsep(&options, ",");
1039                 if (p != NULL && *p) {
1040                         token = match_token(p, tokens, args);
1041                         if (token == Opt_snapshot) {
1042                                 if (!(sd->flags & MS_RDONLY))
1043                                         ret++;
1044                                 else {
1045                                         ret = match_int(&args[0], &option);
1046                                         if (!ret) {
1047                                                 if (option > 0)
1048                                                         sd->cno = option;
1049                                                 else
1050                                                         ret++;
1051                                         }
1052                                 }
1053                         }
1054                         if (ret)
1055                                 printk(KERN_ERR
1056                                        "NILFS: invalid mount option: %s\n", p);
1057                 }
1058                 if (!options)
1059                         break;
1060                 BUG_ON(options == data);
1061                 *(options - 1) = ',';
1062         } while (!ret);
1063         return ret;
1064 }
1065
1066 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1067 {
1068         s->s_bdev = data;
1069         s->s_dev = s->s_bdev->bd_dev;
1070         return 0;
1071 }
1072
1073 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1074 {
1075         return (void *)s->s_bdev == data;
1076 }
1077
1078 static int
1079 nilfs_get_sb(struct file_system_type *fs_type, int flags,
1080              const char *dev_name, void *data, struct vfsmount *mnt)
1081 {
1082         struct nilfs_super_data sd;
1083         struct super_block *s;
1084         fmode_t mode = FMODE_READ;
1085         struct dentry *root_dentry;
1086         int err, s_new = false;
1087
1088         if (!(flags & MS_RDONLY))
1089                 mode |= FMODE_WRITE;
1090
1091         sd.bdev = open_bdev_exclusive(dev_name, mode, fs_type);
1092         if (IS_ERR(sd.bdev))
1093                 return PTR_ERR(sd.bdev);
1094
1095         sd.cno = 0;
1096         sd.flags = flags;
1097         if (nilfs_identify((char *)data, &sd)) {
1098                 err = -EINVAL;
1099                 goto failed;
1100         }
1101
1102         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, sd.bdev);
1103         if (IS_ERR(s)) {
1104                 err = PTR_ERR(s);
1105                 goto failed;
1106         }
1107
1108         if (!s->s_root) {
1109                 char b[BDEVNAME_SIZE];
1110
1111                 s_new = true;
1112
1113                 /* New superblock instance created */
1114                 s->s_flags = flags;
1115                 s->s_mode = mode;
1116                 strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
1117                 sb_set_blocksize(s, block_size(sd.bdev));
1118
1119                 err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
1120                 if (err)
1121                         goto failed_super;
1122
1123                 s->s_flags |= MS_ACTIVE;
1124         } else if (!sd.cno) {
1125                 int busy = false;
1126
1127                 if (nilfs_tree_was_touched(s->s_root)) {
1128                         busy = nilfs_try_to_shrink_tree(s->s_root);
1129                         if (busy && (flags ^ s->s_flags) & MS_RDONLY) {
1130                                 printk(KERN_ERR "NILFS: the device already "
1131                                        "has a %s mount.\n",
1132                                        (s->s_flags & MS_RDONLY) ?
1133                                        "read-only" : "read/write");
1134                                 err = -EBUSY;
1135                                 goto failed_super;
1136                         }
1137                 }
1138                 if (!busy) {
1139                         /*
1140                          * Try remount to setup mount states if the current
1141                          * tree is not mounted and only snapshots use this sb.
1142                          */
1143                         err = nilfs_remount(s, &flags, data);
1144                         if (err)
1145                                 goto failed_super;
1146                 }
1147         }
1148
1149         if (sd.cno) {
1150                 err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
1151                 if (err)
1152                         goto failed_super;
1153         } else {
1154                 root_dentry = dget(s->s_root);
1155         }
1156
1157         if (!s_new)
1158                 close_bdev_exclusive(sd.bdev, mode);
1159
1160         mnt->mnt_sb = s;
1161         mnt->mnt_root = root_dentry;
1162         return 0;
1163
1164  failed_super:
1165         deactivate_locked_super(s);
1166
1167  failed:
1168         if (!s_new)
1169                 close_bdev_exclusive(sd.bdev, mode);
1170         return err;
1171 }
1172
1173 struct file_system_type nilfs_fs_type = {
1174         .owner    = THIS_MODULE,
1175         .name     = "nilfs2",
1176         .get_sb   = nilfs_get_sb,
1177         .kill_sb  = kill_block_super,
1178         .fs_flags = FS_REQUIRES_DEV,
1179 };
1180
1181 static void nilfs_inode_init_once(void *obj)
1182 {
1183         struct nilfs_inode_info *ii = obj;
1184
1185         INIT_LIST_HEAD(&ii->i_dirty);
1186 #ifdef CONFIG_NILFS_XATTR
1187         init_rwsem(&ii->xattr_sem);
1188 #endif
1189         nilfs_btnode_cache_init_once(&ii->i_btnode_cache);
1190         ii->i_bmap = &ii->i_bmap_data;
1191         inode_init_once(&ii->vfs_inode);
1192 }
1193
1194 static void nilfs_segbuf_init_once(void *obj)
1195 {
1196         memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1197 }
1198
1199 static void nilfs_destroy_cachep(void)
1200 {
1201         if (nilfs_inode_cachep)
1202                 kmem_cache_destroy(nilfs_inode_cachep);
1203         if (nilfs_transaction_cachep)
1204                 kmem_cache_destroy(nilfs_transaction_cachep);
1205         if (nilfs_segbuf_cachep)
1206                 kmem_cache_destroy(nilfs_segbuf_cachep);
1207         if (nilfs_btree_path_cache)
1208                 kmem_cache_destroy(nilfs_btree_path_cache);
1209 }
1210
1211 static int __init nilfs_init_cachep(void)
1212 {
1213         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1214                         sizeof(struct nilfs_inode_info), 0,
1215                         SLAB_RECLAIM_ACCOUNT, nilfs_inode_init_once);
1216         if (!nilfs_inode_cachep)
1217                 goto fail;
1218
1219         nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1220                         sizeof(struct nilfs_transaction_info), 0,
1221                         SLAB_RECLAIM_ACCOUNT, NULL);
1222         if (!nilfs_transaction_cachep)
1223                 goto fail;
1224
1225         nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1226                         sizeof(struct nilfs_segment_buffer), 0,
1227                         SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1228         if (!nilfs_segbuf_cachep)
1229                 goto fail;
1230
1231         nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1232                         sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1233                         0, 0, NULL);
1234         if (!nilfs_btree_path_cache)
1235                 goto fail;
1236
1237         return 0;
1238
1239 fail:
1240         nilfs_destroy_cachep();
1241         return -ENOMEM;
1242 }
1243
1244 static int __init init_nilfs_fs(void)
1245 {
1246         int err;
1247
1248         err = nilfs_init_cachep();
1249         if (err)
1250                 goto fail;
1251
1252         err = register_filesystem(&nilfs_fs_type);
1253         if (err)
1254                 goto free_cachep;
1255
1256         printk(KERN_INFO "NILFS version 2 loaded\n");
1257         return 0;
1258
1259 free_cachep:
1260         nilfs_destroy_cachep();
1261 fail:
1262         return err;
1263 }
1264
1265 static void __exit exit_nilfs_fs(void)
1266 {
1267         nilfs_destroy_cachep();
1268         unregister_filesystem(&nilfs_fs_type);
1269 }
1270
1271 module_init(init_nilfs_fs)
1272 module_exit(exit_nilfs_fs)