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1 /*
2  * super.c - NILFS module and super block management.
3  *
4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
19  *
20  * Written by Ryusuke Konishi <ryusuke@osrg.net>
21  */
22 /*
23  *  linux/fs/ext2/super.c
24  *
25  * Copyright (C) 1992, 1993, 1994, 1995
26  * Remy Card (card@masi.ibp.fr)
27  * Laboratoire MASI - Institut Blaise Pascal
28  * Universite Pierre et Marie Curie (Paris VI)
29  *
30  *  from
31  *
32  *  linux/fs/minix/inode.c
33  *
34  *  Copyright (C) 1991, 1992  Linus Torvalds
35  *
36  *  Big-endian to little-endian byte-swapping/bitmaps by
37  *        David S. Miller (davem@caip.rutgers.edu), 1995
38  */
39
40 #include <linux/module.h>
41 #include <linux/string.h>
42 #include <linux/slab.h>
43 #include <linux/init.h>
44 #include <linux/blkdev.h>
45 #include <linux/parser.h>
46 #include <linux/random.h>
47 #include <linux/crc32.h>
48 #include <linux/smp_lock.h>
49 #include <linux/vfs.h>
50 #include <linux/writeback.h>
51 #include <linux/kobject.h>
52 #include <linux/exportfs.h>
53 #include <linux/seq_file.h>
54 #include <linux/mount.h>
55 #include "nilfs.h"
56 #include "mdt.h"
57 #include "alloc.h"
58 #include "btree.h"
59 #include "btnode.h"
60 #include "page.h"
61 #include "cpfile.h"
62 #include "ifile.h"
63 #include "dat.h"
64 #include "segment.h"
65 #include "segbuf.h"
66
67 MODULE_AUTHOR("NTT Corp.");
68 MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
69                    "(NILFS)");
70 MODULE_LICENSE("GPL");
71
72 struct kmem_cache *nilfs_inode_cachep;
73 struct kmem_cache *nilfs_transaction_cachep;
74 struct kmem_cache *nilfs_segbuf_cachep;
75 struct kmem_cache *nilfs_btree_path_cache;
76
77 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
78
79 static void nilfs_set_error(struct nilfs_sb_info *sbi)
80 {
81         struct the_nilfs *nilfs = sbi->s_nilfs;
82         struct nilfs_super_block **sbp;
83
84         down_write(&nilfs->ns_sem);
85         if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
86                 nilfs->ns_mount_state |= NILFS_ERROR_FS;
87                 sbp = nilfs_prepare_super(sbi, 0);
88                 if (likely(sbp)) {
89                         sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
90                         if (sbp[1])
91                                 sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
92                         nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
93                 }
94         }
95         up_write(&nilfs->ns_sem);
96 }
97
98 /**
99  * nilfs_error() - report failure condition on a filesystem
100  *
101  * nilfs_error() sets an ERROR_FS flag on the superblock as well as
102  * reporting an error message.  It should be called when NILFS detects
103  * incoherences or defects of meta data on disk.  As for sustainable
104  * errors such as a single-shot I/O error, nilfs_warning() or the printk()
105  * function should be used instead.
106  *
107  * The segment constructor must not call this function because it can
108  * kill itself.
109  */
110 void nilfs_error(struct super_block *sb, const char *function,
111                  const char *fmt, ...)
112 {
113         struct nilfs_sb_info *sbi = NILFS_SB(sb);
114         va_list args;
115
116         va_start(args, fmt);
117         printk(KERN_CRIT "NILFS error (device %s): %s: ", sb->s_id, function);
118         vprintk(fmt, args);
119         printk("\n");
120         va_end(args);
121
122         if (!(sb->s_flags & MS_RDONLY)) {
123                 nilfs_set_error(sbi);
124
125                 if (nilfs_test_opt(sbi, ERRORS_RO)) {
126                         printk(KERN_CRIT "Remounting filesystem read-only\n");
127                         sb->s_flags |= MS_RDONLY;
128                 }
129         }
130
131         if (nilfs_test_opt(sbi, ERRORS_PANIC))
132                 panic("NILFS (device %s): panic forced after error\n",
133                       sb->s_id);
134 }
135
136 void nilfs_warning(struct super_block *sb, const char *function,
137                    const char *fmt, ...)
138 {
139         va_list args;
140
141         va_start(args, fmt);
142         printk(KERN_WARNING "NILFS warning (device %s): %s: ",
143                sb->s_id, function);
144         vprintk(fmt, args);
145         printk("\n");
146         va_end(args);
147 }
148
149
150 struct inode *nilfs_alloc_inode_common(struct the_nilfs *nilfs)
151 {
152         struct nilfs_inode_info *ii;
153
154         ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
155         if (!ii)
156                 return NULL;
157         ii->i_bh = NULL;
158         ii->i_state = 0;
159         ii->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         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
172 }
173
174 static int nilfs_sync_super(struct nilfs_sb_info *sbi, int flag)
175 {
176         struct the_nilfs *nilfs = sbi->s_nilfs;
177         int err;
178         int barrier_done = 0;
179
180         if (nilfs_test_opt(sbi, BARRIER)) {
181                 set_buffer_ordered(nilfs->ns_sbh[0]);
182                 barrier_done = 1;
183         }
184  retry:
185         set_buffer_dirty(nilfs->ns_sbh[0]);
186         err = sync_dirty_buffer(nilfs->ns_sbh[0]);
187         if (err == -EOPNOTSUPP && barrier_done) {
188                 nilfs_warning(sbi->s_super, __func__,
189                               "barrier-based sync failed. "
190                               "disabling barriers\n");
191                 nilfs_clear_opt(sbi, BARRIER);
192                 barrier_done = 0;
193                 clear_buffer_ordered(nilfs->ns_sbh[0]);
194                 goto retry;
195         }
196         if (unlikely(err)) {
197                 printk(KERN_ERR
198                        "NILFS: unable to write superblock (err=%d)\n", err);
199                 if (err == -EIO && nilfs->ns_sbh[1]) {
200                         /*
201                          * sbp[0] points to newer log than sbp[1],
202                          * so copy sbp[0] to sbp[1] to take over sbp[0].
203                          */
204                         memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
205                                nilfs->ns_sbsize);
206                         nilfs_fall_back_super_block(nilfs);
207                         goto retry;
208                 }
209         } else {
210                 struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
211
212                 nilfs->ns_sbwcount++;
213
214                 /*
215                  * The latest segment becomes trailable from the position
216                  * written in superblock.
217                  */
218                 clear_nilfs_discontinued(nilfs);
219
220                 /* update GC protection for recent segments */
221                 if (nilfs->ns_sbh[1]) {
222                         if (flag == NILFS_SB_COMMIT_ALL) {
223                                 set_buffer_dirty(nilfs->ns_sbh[1]);
224                                 if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
225                                         goto out;
226                         }
227                         if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
228                             le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
229                                 sbp = nilfs->ns_sbp[1];
230                 }
231
232                 spin_lock(&nilfs->ns_last_segment_lock);
233                 nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
234                 spin_unlock(&nilfs->ns_last_segment_lock);
235         }
236  out:
237         return err;
238 }
239
240 void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
241                           struct the_nilfs *nilfs)
242 {
243         sector_t nfreeblocks;
244
245         /* nilfs->ns_sem must be locked by the caller. */
246         nilfs_count_free_blocks(nilfs, &nfreeblocks);
247         sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
248
249         spin_lock(&nilfs->ns_last_segment_lock);
250         sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
251         sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
252         sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
253         spin_unlock(&nilfs->ns_last_segment_lock);
254 }
255
256 struct nilfs_super_block **nilfs_prepare_super(struct nilfs_sb_info *sbi,
257                                                int flip)
258 {
259         struct the_nilfs *nilfs = sbi->s_nilfs;
260         struct nilfs_super_block **sbp = nilfs->ns_sbp;
261
262         /* nilfs->ns_sem must be locked by the caller. */
263         if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
264                 if (sbp[1] &&
265                     sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
266                         memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
267                 } else {
268                         printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
269                                sbi->s_super->s_id);
270                         return NULL;
271                 }
272         } else if (sbp[1] &&
273                    sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
274                         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
275         }
276
277         if (flip && sbp[1])
278                 nilfs_swap_super_block(nilfs);
279
280         return sbp;
281 }
282
283 int nilfs_commit_super(struct nilfs_sb_info *sbi, int flag)
284 {
285         struct the_nilfs *nilfs = sbi->s_nilfs;
286         struct nilfs_super_block **sbp = nilfs->ns_sbp;
287         time_t t;
288
289         /* nilfs->ns_sem must be locked by the caller. */
290         t = get_seconds();
291         nilfs->ns_sbwtime = t;
292         sbp[0]->s_wtime = cpu_to_le64(t);
293         sbp[0]->s_sum = 0;
294         sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
295                                              (unsigned char *)sbp[0],
296                                              nilfs->ns_sbsize));
297         if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
298                 sbp[1]->s_wtime = sbp[0]->s_wtime;
299                 sbp[1]->s_sum = 0;
300                 sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
301                                             (unsigned char *)sbp[1],
302                                             nilfs->ns_sbsize));
303         }
304         clear_nilfs_sb_dirty(nilfs);
305         return nilfs_sync_super(sbi, flag);
306 }
307
308 /**
309  * nilfs_cleanup_super() - write filesystem state for cleanup
310  * @sbi: nilfs_sb_info to be unmounted or degraded to read-only
311  *
312  * This function restores state flags in the on-disk super block.
313  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
314  * filesystem was not clean previously.
315  */
316 int nilfs_cleanup_super(struct nilfs_sb_info *sbi)
317 {
318         struct nilfs_super_block **sbp;
319         int flag = NILFS_SB_COMMIT;
320         int ret = -EIO;
321
322         sbp = nilfs_prepare_super(sbi, 0);
323         if (sbp) {
324                 sbp[0]->s_state = cpu_to_le16(sbi->s_nilfs->ns_mount_state);
325                 nilfs_set_log_cursor(sbp[0], sbi->s_nilfs);
326                 if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
327                         /*
328                          * make the "clean" flag also to the opposite
329                          * super block if both super blocks point to
330                          * the same checkpoint.
331                          */
332                         sbp[1]->s_state = sbp[0]->s_state;
333                         flag = NILFS_SB_COMMIT_ALL;
334                 }
335                 ret = nilfs_commit_super(sbi, flag);
336         }
337         return ret;
338 }
339
340 static void nilfs_put_super(struct super_block *sb)
341 {
342         struct nilfs_sb_info *sbi = NILFS_SB(sb);
343         struct the_nilfs *nilfs = sbi->s_nilfs;
344
345         lock_kernel();
346
347         nilfs_detach_segment_constructor(sbi);
348
349         if (!(sb->s_flags & MS_RDONLY)) {
350                 down_write(&nilfs->ns_sem);
351                 nilfs_cleanup_super(sbi);
352                 up_write(&nilfs->ns_sem);
353         }
354         down_write(&nilfs->ns_super_sem);
355         if (nilfs->ns_current == sbi)
356                 nilfs->ns_current = NULL;
357         up_write(&nilfs->ns_super_sem);
358
359         nilfs_detach_checkpoint(sbi);
360         put_nilfs(sbi->s_nilfs);
361         sbi->s_super = NULL;
362         sb->s_fs_info = NULL;
363         nilfs_put_sbinfo(sbi);
364
365         unlock_kernel();
366 }
367
368 static int nilfs_sync_fs(struct super_block *sb, int wait)
369 {
370         struct nilfs_sb_info *sbi = NILFS_SB(sb);
371         struct the_nilfs *nilfs = sbi->s_nilfs;
372         struct nilfs_super_block **sbp;
373         int err = 0;
374
375         /* This function is called when super block should be written back */
376         if (wait)
377                 err = nilfs_construct_segment(sb);
378
379         down_write(&nilfs->ns_sem);
380         if (nilfs_sb_dirty(nilfs)) {
381                 sbp = nilfs_prepare_super(sbi, nilfs_sb_will_flip(nilfs));
382                 if (likely(sbp)) {
383                         nilfs_set_log_cursor(sbp[0], nilfs);
384                         nilfs_commit_super(sbi, NILFS_SB_COMMIT);
385                 }
386         }
387         up_write(&nilfs->ns_sem);
388
389         return err;
390 }
391
392 int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno)
393 {
394         struct the_nilfs *nilfs = sbi->s_nilfs;
395         struct nilfs_checkpoint *raw_cp;
396         struct buffer_head *bh_cp;
397         int err;
398
399         down_write(&nilfs->ns_super_sem);
400         list_add(&sbi->s_list, &nilfs->ns_supers);
401         up_write(&nilfs->ns_super_sem);
402
403         sbi->s_ifile = nilfs_ifile_new(sbi, nilfs->ns_inode_size);
404         if (!sbi->s_ifile)
405                 return -ENOMEM;
406
407         down_read(&nilfs->ns_segctor_sem);
408         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
409                                           &bh_cp);
410         up_read(&nilfs->ns_segctor_sem);
411         if (unlikely(err)) {
412                 if (err == -ENOENT || err == -EINVAL) {
413                         printk(KERN_ERR
414                                "NILFS: Invalid checkpoint "
415                                "(checkpoint number=%llu)\n",
416                                (unsigned long long)cno);
417                         err = -EINVAL;
418                 }
419                 goto failed;
420         }
421         err = nilfs_read_inode_common(sbi->s_ifile, &raw_cp->cp_ifile_inode);
422         if (unlikely(err))
423                 goto failed_bh;
424         atomic_set(&sbi->s_inodes_count, le64_to_cpu(raw_cp->cp_inodes_count));
425         atomic_set(&sbi->s_blocks_count, le64_to_cpu(raw_cp->cp_blocks_count));
426
427         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
428         return 0;
429
430  failed_bh:
431         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
432  failed:
433         nilfs_mdt_destroy(sbi->s_ifile);
434         sbi->s_ifile = NULL;
435
436         down_write(&nilfs->ns_super_sem);
437         list_del_init(&sbi->s_list);
438         up_write(&nilfs->ns_super_sem);
439
440         return err;
441 }
442
443 void nilfs_detach_checkpoint(struct nilfs_sb_info *sbi)
444 {
445         struct the_nilfs *nilfs = sbi->s_nilfs;
446
447         nilfs_mdt_destroy(sbi->s_ifile);
448         sbi->s_ifile = NULL;
449         down_write(&nilfs->ns_super_sem);
450         list_del_init(&sbi->s_list);
451         up_write(&nilfs->ns_super_sem);
452 }
453
454 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
455 {
456         struct super_block *sb = dentry->d_sb;
457         struct nilfs_sb_info *sbi = NILFS_SB(sb);
458         struct the_nilfs *nilfs = sbi->s_nilfs;
459         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
460         unsigned long long blocks;
461         unsigned long overhead;
462         unsigned long nrsvblocks;
463         sector_t nfreeblocks;
464         int err;
465
466         /*
467          * Compute all of the segment blocks
468          *
469          * The blocks before first segment and after last segment
470          * are excluded.
471          */
472         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
473                 - nilfs->ns_first_data_block;
474         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
475
476         /*
477          * Compute the overhead
478          *
479          * When distributing meta data blocks outside segment structure,
480          * We must count them as the overhead.
481          */
482         overhead = 0;
483
484         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
485         if (unlikely(err))
486                 return err;
487
488         buf->f_type = NILFS_SUPER_MAGIC;
489         buf->f_bsize = sb->s_blocksize;
490         buf->f_blocks = blocks - overhead;
491         buf->f_bfree = nfreeblocks;
492         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
493                 (buf->f_bfree - nrsvblocks) : 0;
494         buf->f_files = atomic_read(&sbi->s_inodes_count);
495         buf->f_ffree = 0; /* nilfs_count_free_inodes(sb); */
496         buf->f_namelen = NILFS_NAME_LEN;
497         buf->f_fsid.val[0] = (u32)id;
498         buf->f_fsid.val[1] = (u32)(id >> 32);
499
500         return 0;
501 }
502
503 static int nilfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
504 {
505         struct super_block *sb = vfs->mnt_sb;
506         struct nilfs_sb_info *sbi = NILFS_SB(sb);
507
508         if (!nilfs_test_opt(sbi, BARRIER))
509                 seq_puts(seq, ",nobarrier");
510         if (nilfs_test_opt(sbi, SNAPSHOT))
511                 seq_printf(seq, ",cp=%llu",
512                            (unsigned long long int)sbi->s_snapshot_cno);
513         if (nilfs_test_opt(sbi, ERRORS_PANIC))
514                 seq_puts(seq, ",errors=panic");
515         if (nilfs_test_opt(sbi, ERRORS_CONT))
516                 seq_puts(seq, ",errors=continue");
517         if (nilfs_test_opt(sbi, STRICT_ORDER))
518                 seq_puts(seq, ",order=strict");
519         if (nilfs_test_opt(sbi, NORECOVERY))
520                 seq_puts(seq, ",norecovery");
521         if (nilfs_test_opt(sbi, DISCARD))
522                 seq_puts(seq, ",discard");
523
524         return 0;
525 }
526
527 static const struct super_operations nilfs_sops = {
528         .alloc_inode    = nilfs_alloc_inode,
529         .destroy_inode  = nilfs_destroy_inode,
530         .dirty_inode    = nilfs_dirty_inode,
531         /* .write_inode    = nilfs_write_inode, */
532         /* .put_inode      = nilfs_put_inode, */
533         /* .drop_inode    = nilfs_drop_inode, */
534         .evict_inode    = nilfs_evict_inode,
535         .put_super      = nilfs_put_super,
536         /* .write_super    = nilfs_write_super, */
537         .sync_fs        = nilfs_sync_fs,
538         /* .write_super_lockfs */
539         /* .unlockfs */
540         .statfs         = nilfs_statfs,
541         .remount_fs     = nilfs_remount,
542         /* .umount_begin */
543         .show_options = nilfs_show_options
544 };
545
546 static struct inode *
547 nilfs_nfs_get_inode(struct super_block *sb, u64 ino, u32 generation)
548 {
549         struct inode *inode;
550
551         if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO &&
552             ino != NILFS_SKETCH_INO)
553                 return ERR_PTR(-ESTALE);
554
555         inode = nilfs_iget(sb, ino);
556         if (IS_ERR(inode))
557                 return ERR_CAST(inode);
558         if (generation && inode->i_generation != generation) {
559                 iput(inode);
560                 return ERR_PTR(-ESTALE);
561         }
562
563         return inode;
564 }
565
566 static struct dentry *
567 nilfs_fh_to_dentry(struct super_block *sb, struct fid *fid, int fh_len,
568                    int fh_type)
569 {
570         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
571                                     nilfs_nfs_get_inode);
572 }
573
574 static struct dentry *
575 nilfs_fh_to_parent(struct super_block *sb, struct fid *fid, int fh_len,
576                    int fh_type)
577 {
578         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
579                                     nilfs_nfs_get_inode);
580 }
581
582 static const struct export_operations nilfs_export_ops = {
583         .fh_to_dentry = nilfs_fh_to_dentry,
584         .fh_to_parent = nilfs_fh_to_parent,
585         .get_parent = nilfs_get_parent,
586 };
587
588 enum {
589         Opt_err_cont, Opt_err_panic, Opt_err_ro,
590         Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
591         Opt_discard, Opt_nodiscard, Opt_err,
592 };
593
594 static match_table_t tokens = {
595         {Opt_err_cont, "errors=continue"},
596         {Opt_err_panic, "errors=panic"},
597         {Opt_err_ro, "errors=remount-ro"},
598         {Opt_barrier, "barrier"},
599         {Opt_nobarrier, "nobarrier"},
600         {Opt_snapshot, "cp=%u"},
601         {Opt_order, "order=%s"},
602         {Opt_norecovery, "norecovery"},
603         {Opt_discard, "discard"},
604         {Opt_nodiscard, "nodiscard"},
605         {Opt_err, NULL}
606 };
607
608 static int parse_options(char *options, struct super_block *sb, int is_remount)
609 {
610         struct nilfs_sb_info *sbi = NILFS_SB(sb);
611         char *p;
612         substring_t args[MAX_OPT_ARGS];
613         int option;
614
615         if (!options)
616                 return 1;
617
618         while ((p = strsep(&options, ",")) != NULL) {
619                 int token;
620                 if (!*p)
621                         continue;
622
623                 token = match_token(p, tokens, args);
624                 switch (token) {
625                 case Opt_barrier:
626                         nilfs_set_opt(sbi, BARRIER);
627                         break;
628                 case Opt_nobarrier:
629                         nilfs_clear_opt(sbi, BARRIER);
630                         break;
631                 case Opt_order:
632                         if (strcmp(args[0].from, "relaxed") == 0)
633                                 /* Ordered data semantics */
634                                 nilfs_clear_opt(sbi, STRICT_ORDER);
635                         else if (strcmp(args[0].from, "strict") == 0)
636                                 /* Strict in-order semantics */
637                                 nilfs_set_opt(sbi, STRICT_ORDER);
638                         else
639                                 return 0;
640                         break;
641                 case Opt_err_panic:
642                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_PANIC);
643                         break;
644                 case Opt_err_ro:
645                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_RO);
646                         break;
647                 case Opt_err_cont:
648                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_CONT);
649                         break;
650                 case Opt_snapshot:
651                         if (match_int(&args[0], &option) || option <= 0)
652                                 return 0;
653                         if (is_remount) {
654                                 if (!nilfs_test_opt(sbi, SNAPSHOT)) {
655                                         printk(KERN_ERR
656                                                "NILFS: cannot change regular "
657                                                "mount to snapshot.\n");
658                                         return 0;
659                                 } else if (option != sbi->s_snapshot_cno) {
660                                         printk(KERN_ERR
661                                                "NILFS: cannot remount to a "
662                                                "different snapshot.\n");
663                                         return 0;
664                                 }
665                                 break;
666                         }
667                         if (!(sb->s_flags & MS_RDONLY)) {
668                                 printk(KERN_ERR "NILFS: cannot mount snapshot "
669                                        "read/write.  A read-only option is "
670                                        "required.\n");
671                                 return 0;
672                         }
673                         sbi->s_snapshot_cno = option;
674                         nilfs_set_opt(sbi, SNAPSHOT);
675                         break;
676                 case Opt_norecovery:
677                         nilfs_set_opt(sbi, NORECOVERY);
678                         break;
679                 case Opt_discard:
680                         nilfs_set_opt(sbi, DISCARD);
681                         break;
682                 case Opt_nodiscard:
683                         nilfs_clear_opt(sbi, DISCARD);
684                         break;
685                 default:
686                         printk(KERN_ERR
687                                "NILFS: Unrecognized mount option \"%s\"\n", p);
688                         return 0;
689                 }
690         }
691         return 1;
692 }
693
694 static inline void
695 nilfs_set_default_options(struct nilfs_sb_info *sbi,
696                           struct nilfs_super_block *sbp)
697 {
698         sbi->s_mount_opt =
699                 NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
700 }
701
702 static int nilfs_setup_super(struct nilfs_sb_info *sbi)
703 {
704         struct the_nilfs *nilfs = sbi->s_nilfs;
705         struct nilfs_super_block **sbp;
706         int max_mnt_count;
707         int mnt_count;
708
709         /* nilfs->ns_sem must be locked by the caller. */
710         sbp = nilfs_prepare_super(sbi, 0);
711         if (!sbp)
712                 return -EIO;
713
714         max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
715         mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
716
717         if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
718                 printk(KERN_WARNING
719                        "NILFS warning: mounting fs with errors\n");
720 #if 0
721         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
722                 printk(KERN_WARNING
723                        "NILFS warning: maximal mount count reached\n");
724 #endif
725         }
726         if (!max_mnt_count)
727                 sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
728
729         sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
730         sbp[0]->s_state =
731                 cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
732         sbp[0]->s_mtime = cpu_to_le64(get_seconds());
733         /* synchronize sbp[1] with sbp[0] */
734         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
735         return nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
736 }
737
738 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
739                                                  u64 pos, int blocksize,
740                                                  struct buffer_head **pbh)
741 {
742         unsigned long long sb_index = pos;
743         unsigned long offset;
744
745         offset = do_div(sb_index, blocksize);
746         *pbh = sb_bread(sb, sb_index);
747         if (!*pbh)
748                 return NULL;
749         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
750 }
751
752 int nilfs_store_magic_and_option(struct super_block *sb,
753                                  struct nilfs_super_block *sbp,
754                                  char *data)
755 {
756         struct nilfs_sb_info *sbi = NILFS_SB(sb);
757
758         sb->s_magic = le16_to_cpu(sbp->s_magic);
759
760         /* FS independent flags */
761 #ifdef NILFS_ATIME_DISABLE
762         sb->s_flags |= MS_NOATIME;
763 #endif
764
765         nilfs_set_default_options(sbi, sbp);
766
767         sbi->s_resuid = le16_to_cpu(sbp->s_def_resuid);
768         sbi->s_resgid = le16_to_cpu(sbp->s_def_resgid);
769         sbi->s_interval = le32_to_cpu(sbp->s_c_interval);
770         sbi->s_watermark = le32_to_cpu(sbp->s_c_block_max);
771
772         return !parse_options(data, sb, 0) ? -EINVAL : 0 ;
773 }
774
775 int nilfs_check_feature_compatibility(struct super_block *sb,
776                                       struct nilfs_super_block *sbp)
777 {
778         __u64 features;
779
780         features = le64_to_cpu(sbp->s_feature_incompat) &
781                 ~NILFS_FEATURE_INCOMPAT_SUPP;
782         if (features) {
783                 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
784                        "optional features (%llx)\n",
785                        (unsigned long long)features);
786                 return -EINVAL;
787         }
788         features = le64_to_cpu(sbp->s_feature_compat_ro) &
789                 ~NILFS_FEATURE_COMPAT_RO_SUPP;
790         if (!(sb->s_flags & MS_RDONLY) && features) {
791                 printk(KERN_ERR "NILFS: couldn't mount RDWR because of "
792                        "unsupported optional features (%llx)\n",
793                        (unsigned long long)features);
794                 return -EINVAL;
795         }
796         return 0;
797 }
798
799 /**
800  * nilfs_fill_super() - initialize a super block instance
801  * @sb: super_block
802  * @data: mount options
803  * @silent: silent mode flag
804  * @nilfs: the_nilfs struct
805  *
806  * This function is called exclusively by nilfs->ns_mount_mutex.
807  * So, the recovery process is protected from other simultaneous mounts.
808  */
809 static int
810 nilfs_fill_super(struct super_block *sb, void *data, int silent,
811                  struct the_nilfs *nilfs)
812 {
813         struct nilfs_sb_info *sbi;
814         struct inode *root;
815         __u64 cno;
816         int err;
817
818         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
819         if (!sbi)
820                 return -ENOMEM;
821
822         sb->s_fs_info = sbi;
823
824         get_nilfs(nilfs);
825         sbi->s_nilfs = nilfs;
826         sbi->s_super = sb;
827         atomic_set(&sbi->s_count, 1);
828
829         err = init_nilfs(nilfs, sbi, (char *)data);
830         if (err)
831                 goto failed_sbi;
832
833         spin_lock_init(&sbi->s_inode_lock);
834         INIT_LIST_HEAD(&sbi->s_dirty_files);
835         INIT_LIST_HEAD(&sbi->s_list);
836
837         /*
838          * Following initialization is overlapped because
839          * nilfs_sb_info structure has been cleared at the beginning.
840          * But we reserve them to keep our interest and make ready
841          * for the future change.
842          */
843         get_random_bytes(&sbi->s_next_generation,
844                          sizeof(sbi->s_next_generation));
845         spin_lock_init(&sbi->s_next_gen_lock);
846
847         sb->s_op = &nilfs_sops;
848         sb->s_export_op = &nilfs_export_ops;
849         sb->s_root = NULL;
850         sb->s_time_gran = 1;
851         sb->s_bdi = nilfs->ns_bdi;
852
853         err = load_nilfs(nilfs, sbi);
854         if (err)
855                 goto failed_sbi;
856
857         cno = nilfs_last_cno(nilfs);
858
859         if (sb->s_flags & MS_RDONLY) {
860                 if (nilfs_test_opt(sbi, SNAPSHOT)) {
861                         down_read(&nilfs->ns_segctor_sem);
862                         err = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile,
863                                                        sbi->s_snapshot_cno);
864                         up_read(&nilfs->ns_segctor_sem);
865                         if (err < 0) {
866                                 if (err == -ENOENT)
867                                         err = -EINVAL;
868                                 goto failed_sbi;
869                         }
870                         if (!err) {
871                                 printk(KERN_ERR
872                                        "NILFS: The specified checkpoint is "
873                                        "not a snapshot "
874                                        "(checkpoint number=%llu).\n",
875                                        (unsigned long long)sbi->s_snapshot_cno);
876                                 err = -EINVAL;
877                                 goto failed_sbi;
878                         }
879                         cno = sbi->s_snapshot_cno;
880                 }
881         }
882
883         err = nilfs_attach_checkpoint(sbi, cno);
884         if (err) {
885                 printk(KERN_ERR "NILFS: error loading a checkpoint"
886                        " (checkpoint number=%llu).\n", (unsigned long long)cno);
887                 goto failed_sbi;
888         }
889
890         if (!(sb->s_flags & MS_RDONLY)) {
891                 err = nilfs_attach_segment_constructor(sbi);
892                 if (err)
893                         goto failed_checkpoint;
894         }
895
896         root = nilfs_iget(sb, NILFS_ROOT_INO);
897         if (IS_ERR(root)) {
898                 printk(KERN_ERR "NILFS: get root inode failed\n");
899                 err = PTR_ERR(root);
900                 goto failed_segctor;
901         }
902         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
903                 iput(root);
904                 printk(KERN_ERR "NILFS: corrupt root inode.\n");
905                 err = -EINVAL;
906                 goto failed_segctor;
907         }
908         sb->s_root = d_alloc_root(root);
909         if (!sb->s_root) {
910                 iput(root);
911                 printk(KERN_ERR "NILFS: get root dentry failed\n");
912                 err = -ENOMEM;
913                 goto failed_segctor;
914         }
915
916         if (!(sb->s_flags & MS_RDONLY)) {
917                 down_write(&nilfs->ns_sem);
918                 nilfs_setup_super(sbi);
919                 up_write(&nilfs->ns_sem);
920         }
921
922         down_write(&nilfs->ns_super_sem);
923         if (!nilfs_test_opt(sbi, SNAPSHOT))
924                 nilfs->ns_current = sbi;
925         up_write(&nilfs->ns_super_sem);
926
927         return 0;
928
929  failed_segctor:
930         nilfs_detach_segment_constructor(sbi);
931
932  failed_checkpoint:
933         nilfs_detach_checkpoint(sbi);
934
935  failed_sbi:
936         put_nilfs(nilfs);
937         sb->s_fs_info = NULL;
938         nilfs_put_sbinfo(sbi);
939         return err;
940 }
941
942 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
943 {
944         struct nilfs_sb_info *sbi = NILFS_SB(sb);
945         struct the_nilfs *nilfs = sbi->s_nilfs;
946         unsigned long old_sb_flags;
947         struct nilfs_mount_options old_opts;
948         int was_snapshot, err;
949
950         lock_kernel();
951
952         down_write(&nilfs->ns_super_sem);
953         old_sb_flags = sb->s_flags;
954         old_opts.mount_opt = sbi->s_mount_opt;
955         old_opts.snapshot_cno = sbi->s_snapshot_cno;
956         was_snapshot = nilfs_test_opt(sbi, SNAPSHOT);
957
958         if (!parse_options(data, sb, 1)) {
959                 err = -EINVAL;
960                 goto restore_opts;
961         }
962         sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
963
964         err = -EINVAL;
965         if (was_snapshot && !(*flags & MS_RDONLY)) {
966                 printk(KERN_ERR "NILFS (device %s): cannot remount snapshot "
967                        "read/write.\n", sb->s_id);
968                 goto restore_opts;
969         }
970
971         if (!nilfs_valid_fs(nilfs)) {
972                 printk(KERN_WARNING "NILFS (device %s): couldn't "
973                        "remount because the filesystem is in an "
974                        "incomplete recovery state.\n", sb->s_id);
975                 goto restore_opts;
976         }
977
978         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
979                 goto out;
980         if (*flags & MS_RDONLY) {
981                 /* Shutting down the segment constructor */
982                 nilfs_detach_segment_constructor(sbi);
983                 sb->s_flags |= MS_RDONLY;
984
985                 /*
986                  * Remounting a valid RW partition RDONLY, so set
987                  * the RDONLY flag and then mark the partition as valid again.
988                  */
989                 down_write(&nilfs->ns_sem);
990                 nilfs_cleanup_super(sbi);
991                 up_write(&nilfs->ns_sem);
992         } else {
993                 __u64 features;
994
995                 /*
996                  * Mounting a RDONLY partition read-write, so reread and
997                  * store the current valid flag.  (It may have been changed
998                  * by fsck since we originally mounted the partition.)
999                  */
1000                 down_read(&nilfs->ns_sem);
1001                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1002                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
1003                 up_read(&nilfs->ns_sem);
1004                 if (features) {
1005                         printk(KERN_WARNING "NILFS (device %s): couldn't "
1006                                "remount RDWR because of unsupported optional "
1007                                "features (%llx)\n",
1008                                sb->s_id, (unsigned long long)features);
1009                         err = -EROFS;
1010                         goto restore_opts;
1011                 }
1012
1013                 sb->s_flags &= ~MS_RDONLY;
1014
1015                 err = nilfs_attach_segment_constructor(sbi);
1016                 if (err)
1017                         goto restore_opts;
1018
1019                 down_write(&nilfs->ns_sem);
1020                 nilfs_setup_super(sbi);
1021                 up_write(&nilfs->ns_sem);
1022         }
1023  out:
1024         up_write(&nilfs->ns_super_sem);
1025         unlock_kernel();
1026         return 0;
1027
1028  restore_opts:
1029         sb->s_flags = old_sb_flags;
1030         sbi->s_mount_opt = old_opts.mount_opt;
1031         sbi->s_snapshot_cno = old_opts.snapshot_cno;
1032         up_write(&nilfs->ns_super_sem);
1033         unlock_kernel();
1034         return err;
1035 }
1036
1037 struct nilfs_super_data {
1038         struct block_device *bdev;
1039         struct nilfs_sb_info *sbi;
1040         __u64 cno;
1041         int flags;
1042 };
1043
1044 /**
1045  * nilfs_identify - pre-read mount options needed to identify mount instance
1046  * @data: mount options
1047  * @sd: nilfs_super_data
1048  */
1049 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1050 {
1051         char *p, *options = data;
1052         substring_t args[MAX_OPT_ARGS];
1053         int option, token;
1054         int ret = 0;
1055
1056         do {
1057                 p = strsep(&options, ",");
1058                 if (p != NULL && *p) {
1059                         token = match_token(p, tokens, args);
1060                         if (token == Opt_snapshot) {
1061                                 if (!(sd->flags & MS_RDONLY))
1062                                         ret++;
1063                                 else {
1064                                         ret = match_int(&args[0], &option);
1065                                         if (!ret) {
1066                                                 if (option > 0)
1067                                                         sd->cno = option;
1068                                                 else
1069                                                         ret++;
1070                                         }
1071                                 }
1072                         }
1073                         if (ret)
1074                                 printk(KERN_ERR
1075                                        "NILFS: invalid mount option: %s\n", p);
1076                 }
1077                 if (!options)
1078                         break;
1079                 BUG_ON(options == data);
1080                 *(options - 1) = ',';
1081         } while (!ret);
1082         return ret;
1083 }
1084
1085 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1086 {
1087         struct nilfs_super_data *sd = data;
1088
1089         s->s_bdev = sd->bdev;
1090         s->s_dev = s->s_bdev->bd_dev;
1091         return 0;
1092 }
1093
1094 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1095 {
1096         struct nilfs_super_data *sd = data;
1097
1098         return sd->sbi && s->s_fs_info == (void *)sd->sbi;
1099 }
1100
1101 static int
1102 nilfs_get_sb(struct file_system_type *fs_type, int flags,
1103              const char *dev_name, void *data, struct vfsmount *mnt)
1104 {
1105         struct nilfs_super_data sd;
1106         struct super_block *s;
1107         fmode_t mode = FMODE_READ;
1108         struct the_nilfs *nilfs;
1109         int err, need_to_close = 1;
1110
1111         if (!(flags & MS_RDONLY))
1112                 mode |= FMODE_WRITE;
1113
1114         sd.bdev = open_bdev_exclusive(dev_name, mode, fs_type);
1115         if (IS_ERR(sd.bdev))
1116                 return PTR_ERR(sd.bdev);
1117
1118         /*
1119          * To get mount instance using sget() vfs-routine, NILFS needs
1120          * much more information than normal filesystems to identify mount
1121          * instance.  For snapshot mounts, not only a mount type (ro-mount
1122          * or rw-mount) but also a checkpoint number is required.
1123          */
1124         sd.cno = 0;
1125         sd.flags = flags;
1126         if (nilfs_identify((char *)data, &sd)) {
1127                 err = -EINVAL;
1128                 goto failed;
1129         }
1130
1131         nilfs = find_or_create_nilfs(sd.bdev);
1132         if (!nilfs) {
1133                 err = -ENOMEM;
1134                 goto failed;
1135         }
1136
1137         mutex_lock(&nilfs->ns_mount_mutex);
1138
1139         if (!sd.cno) {
1140                 /*
1141                  * Check if an exclusive mount exists or not.
1142                  * Snapshot mounts coexist with a current mount
1143                  * (i.e. rw-mount or ro-mount), whereas rw-mount and
1144                  * ro-mount are mutually exclusive.
1145                  */
1146                 down_read(&nilfs->ns_super_sem);
1147                 if (nilfs->ns_current &&
1148                     ((nilfs->ns_current->s_super->s_flags ^ flags)
1149                      & MS_RDONLY)) {
1150                         up_read(&nilfs->ns_super_sem);
1151                         err = -EBUSY;
1152                         goto failed_unlock;
1153                 }
1154                 up_read(&nilfs->ns_super_sem);
1155         }
1156
1157         /*
1158          * Find existing nilfs_sb_info struct
1159          */
1160         sd.sbi = nilfs_find_sbinfo(nilfs, !(flags & MS_RDONLY), sd.cno);
1161
1162         /*
1163          * Get super block instance holding the nilfs_sb_info struct.
1164          * A new instance is allocated if no existing mount is present or
1165          * existing instance has been unmounted.
1166          */
1167         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, &sd);
1168         if (sd.sbi)
1169                 nilfs_put_sbinfo(sd.sbi);
1170
1171         if (IS_ERR(s)) {
1172                 err = PTR_ERR(s);
1173                 goto failed_unlock;
1174         }
1175
1176         if (!s->s_root) {
1177                 char b[BDEVNAME_SIZE];
1178
1179                 /* New superblock instance created */
1180                 s->s_flags = flags;
1181                 s->s_mode = mode;
1182                 strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
1183                 sb_set_blocksize(s, block_size(sd.bdev));
1184
1185                 err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0,
1186                                        nilfs);
1187                 if (err)
1188                         goto cancel_new;
1189
1190                 s->s_flags |= MS_ACTIVE;
1191                 need_to_close = 0;
1192         }
1193
1194         mutex_unlock(&nilfs->ns_mount_mutex);
1195         put_nilfs(nilfs);
1196         if (need_to_close)
1197                 close_bdev_exclusive(sd.bdev, mode);
1198         simple_set_mnt(mnt, s);
1199         return 0;
1200
1201  failed_unlock:
1202         mutex_unlock(&nilfs->ns_mount_mutex);
1203         put_nilfs(nilfs);
1204  failed:
1205         close_bdev_exclusive(sd.bdev, mode);
1206
1207         return err;
1208
1209  cancel_new:
1210         /* Abandoning the newly allocated superblock */
1211         mutex_unlock(&nilfs->ns_mount_mutex);
1212         put_nilfs(nilfs);
1213         deactivate_locked_super(s);
1214         /*
1215          * deactivate_locked_super() invokes close_bdev_exclusive().
1216          * We must finish all post-cleaning before this call;
1217          * put_nilfs() needs the block device.
1218          */
1219         return err;
1220 }
1221
1222 struct file_system_type nilfs_fs_type = {
1223         .owner    = THIS_MODULE,
1224         .name     = "nilfs2",
1225         .get_sb   = nilfs_get_sb,
1226         .kill_sb  = kill_block_super,
1227         .fs_flags = FS_REQUIRES_DEV,
1228 };
1229
1230 static void nilfs_inode_init_once(void *obj)
1231 {
1232         struct nilfs_inode_info *ii = obj;
1233
1234         INIT_LIST_HEAD(&ii->i_dirty);
1235 #ifdef CONFIG_NILFS_XATTR
1236         init_rwsem(&ii->xattr_sem);
1237 #endif
1238         nilfs_btnode_cache_init_once(&ii->i_btnode_cache);
1239         ii->i_bmap = &ii->i_bmap_data;
1240         inode_init_once(&ii->vfs_inode);
1241 }
1242
1243 static void nilfs_segbuf_init_once(void *obj)
1244 {
1245         memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1246 }
1247
1248 static void nilfs_destroy_cachep(void)
1249 {
1250         if (nilfs_inode_cachep)
1251                 kmem_cache_destroy(nilfs_inode_cachep);
1252         if (nilfs_transaction_cachep)
1253                 kmem_cache_destroy(nilfs_transaction_cachep);
1254         if (nilfs_segbuf_cachep)
1255                 kmem_cache_destroy(nilfs_segbuf_cachep);
1256         if (nilfs_btree_path_cache)
1257                 kmem_cache_destroy(nilfs_btree_path_cache);
1258 }
1259
1260 static int __init nilfs_init_cachep(void)
1261 {
1262         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1263                         sizeof(struct nilfs_inode_info), 0,
1264                         SLAB_RECLAIM_ACCOUNT, nilfs_inode_init_once);
1265         if (!nilfs_inode_cachep)
1266                 goto fail;
1267
1268         nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1269                         sizeof(struct nilfs_transaction_info), 0,
1270                         SLAB_RECLAIM_ACCOUNT, NULL);
1271         if (!nilfs_transaction_cachep)
1272                 goto fail;
1273
1274         nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1275                         sizeof(struct nilfs_segment_buffer), 0,
1276                         SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1277         if (!nilfs_segbuf_cachep)
1278                 goto fail;
1279
1280         nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1281                         sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1282                         0, 0, NULL);
1283         if (!nilfs_btree_path_cache)
1284                 goto fail;
1285
1286         return 0;
1287
1288 fail:
1289         nilfs_destroy_cachep();
1290         return -ENOMEM;
1291 }
1292
1293 static int __init init_nilfs_fs(void)
1294 {
1295         int err;
1296
1297         err = nilfs_init_cachep();
1298         if (err)
1299                 goto fail;
1300
1301         err = register_filesystem(&nilfs_fs_type);
1302         if (err)
1303                 goto free_cachep;
1304
1305         printk(KERN_INFO "NILFS version 2 loaded\n");
1306         return 0;
1307
1308 free_cachep:
1309         nilfs_destroy_cachep();
1310 fail:
1311         return err;
1312 }
1313
1314 static void __exit exit_nilfs_fs(void)
1315 {
1316         nilfs_destroy_cachep();
1317         unregister_filesystem(&nilfs_fs_type);
1318 }
1319
1320 module_init(init_nilfs_fs)
1321 module_exit(exit_nilfs_fs)