GNU Linux-libre 5.19-rc6-gnu
[releases.git] / fs / nilfs2 / super.c
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * NILFS module and super block management.
4  *
5  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6  *
7  * Written by Ryusuke Konishi.
8  */
9 /*
10  *  linux/fs/ext2/super.c
11  *
12  * Copyright (C) 1992, 1993, 1994, 1995
13  * Remy Card (card@masi.ibp.fr)
14  * Laboratoire MASI - Institut Blaise Pascal
15  * Universite Pierre et Marie Curie (Paris VI)
16  *
17  *  from
18  *
19  *  linux/fs/minix/inode.c
20  *
21  *  Copyright (C) 1991, 1992  Linus Torvalds
22  *
23  *  Big-endian to little-endian byte-swapping/bitmaps by
24  *        David S. Miller (davem@caip.rutgers.edu), 1995
25  */
26
27 #include <linux/module.h>
28 #include <linux/string.h>
29 #include <linux/slab.h>
30 #include <linux/init.h>
31 #include <linux/blkdev.h>
32 #include <linux/parser.h>
33 #include <linux/crc32.h>
34 #include <linux/vfs.h>
35 #include <linux/writeback.h>
36 #include <linux/seq_file.h>
37 #include <linux/mount.h>
38 #include "nilfs.h"
39 #include "export.h"
40 #include "mdt.h"
41 #include "alloc.h"
42 #include "btree.h"
43 #include "btnode.h"
44 #include "page.h"
45 #include "cpfile.h"
46 #include "sufile.h" /* nilfs_sufile_resize(), nilfs_sufile_set_alloc_range() */
47 #include "ifile.h"
48 #include "dat.h"
49 #include "segment.h"
50 #include "segbuf.h"
51
52 MODULE_AUTHOR("NTT Corp.");
53 MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
54                    "(NILFS)");
55 MODULE_LICENSE("GPL");
56
57 static struct kmem_cache *nilfs_inode_cachep;
58 struct kmem_cache *nilfs_transaction_cachep;
59 struct kmem_cache *nilfs_segbuf_cachep;
60 struct kmem_cache *nilfs_btree_path_cache;
61
62 static int nilfs_setup_super(struct super_block *sb, int is_mount);
63 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
64
65 void __nilfs_msg(struct super_block *sb, const char *fmt, ...)
66 {
67         struct va_format vaf;
68         va_list args;
69         int level;
70
71         va_start(args, fmt);
72
73         level = printk_get_level(fmt);
74         vaf.fmt = printk_skip_level(fmt);
75         vaf.va = &args;
76
77         if (sb)
78                 printk("%c%cNILFS (%s): %pV\n",
79                        KERN_SOH_ASCII, level, sb->s_id, &vaf);
80         else
81                 printk("%c%cNILFS: %pV\n",
82                        KERN_SOH_ASCII, level, &vaf);
83
84         va_end(args);
85 }
86
87 static void nilfs_set_error(struct super_block *sb)
88 {
89         struct the_nilfs *nilfs = sb->s_fs_info;
90         struct nilfs_super_block **sbp;
91
92         down_write(&nilfs->ns_sem);
93         if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
94                 nilfs->ns_mount_state |= NILFS_ERROR_FS;
95                 sbp = nilfs_prepare_super(sb, 0);
96                 if (likely(sbp)) {
97                         sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
98                         if (sbp[1])
99                                 sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
100                         nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
101                 }
102         }
103         up_write(&nilfs->ns_sem);
104 }
105
106 /**
107  * __nilfs_error() - report failure condition on a filesystem
108  *
109  * __nilfs_error() sets an ERROR_FS flag on the superblock as well as
110  * reporting an error message.  This function should be called when
111  * NILFS detects incoherences or defects of meta data on disk.
112  *
113  * This implements the body of nilfs_error() macro.  Normally,
114  * nilfs_error() should be used.  As for sustainable errors such as a
115  * single-shot I/O error, nilfs_err() should be used instead.
116  *
117  * Callers should not add a trailing newline since this will do it.
118  */
119 void __nilfs_error(struct super_block *sb, const char *function,
120                    const char *fmt, ...)
121 {
122         struct the_nilfs *nilfs = sb->s_fs_info;
123         struct va_format vaf;
124         va_list args;
125
126         va_start(args, fmt);
127
128         vaf.fmt = fmt;
129         vaf.va = &args;
130
131         printk(KERN_CRIT "NILFS error (device %s): %s: %pV\n",
132                sb->s_id, function, &vaf);
133
134         va_end(args);
135
136         if (!sb_rdonly(sb)) {
137                 nilfs_set_error(sb);
138
139                 if (nilfs_test_opt(nilfs, ERRORS_RO)) {
140                         printk(KERN_CRIT "Remounting filesystem read-only\n");
141                         sb->s_flags |= SB_RDONLY;
142                 }
143         }
144
145         if (nilfs_test_opt(nilfs, ERRORS_PANIC))
146                 panic("NILFS (device %s): panic forced after error\n",
147                       sb->s_id);
148 }
149
150 struct inode *nilfs_alloc_inode(struct super_block *sb)
151 {
152         struct nilfs_inode_info *ii;
153
154         ii = alloc_inode_sb(sb, nilfs_inode_cachep, GFP_NOFS);
155         if (!ii)
156                 return NULL;
157         ii->i_bh = NULL;
158         ii->i_state = 0;
159         ii->i_cno = 0;
160         ii->i_assoc_inode = NULL;
161         ii->i_bmap = &ii->i_bmap_data;
162         return &ii->vfs_inode;
163 }
164
165 static void nilfs_free_inode(struct inode *inode)
166 {
167         if (nilfs_is_metadata_file_inode(inode))
168                 nilfs_mdt_destroy(inode);
169
170         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
171 }
172
173 static int nilfs_sync_super(struct super_block *sb, int flag)
174 {
175         struct the_nilfs *nilfs = sb->s_fs_info;
176         int err;
177
178  retry:
179         set_buffer_dirty(nilfs->ns_sbh[0]);
180         if (nilfs_test_opt(nilfs, BARRIER)) {
181                 err = __sync_dirty_buffer(nilfs->ns_sbh[0],
182                                           REQ_SYNC | REQ_PREFLUSH | REQ_FUA);
183         } else {
184                 err = sync_dirty_buffer(nilfs->ns_sbh[0]);
185         }
186
187         if (unlikely(err)) {
188                 nilfs_err(sb, "unable to write superblock: err=%d", err);
189                 if (err == -EIO && nilfs->ns_sbh[1]) {
190                         /*
191                          * sbp[0] points to newer log than sbp[1],
192                          * so copy sbp[0] to sbp[1] to take over sbp[0].
193                          */
194                         memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
195                                nilfs->ns_sbsize);
196                         nilfs_fall_back_super_block(nilfs);
197                         goto retry;
198                 }
199         } else {
200                 struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
201
202                 nilfs->ns_sbwcount++;
203
204                 /*
205                  * The latest segment becomes trailable from the position
206                  * written in superblock.
207                  */
208                 clear_nilfs_discontinued(nilfs);
209
210                 /* update GC protection for recent segments */
211                 if (nilfs->ns_sbh[1]) {
212                         if (flag == NILFS_SB_COMMIT_ALL) {
213                                 set_buffer_dirty(nilfs->ns_sbh[1]);
214                                 if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
215                                         goto out;
216                         }
217                         if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
218                             le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
219                                 sbp = nilfs->ns_sbp[1];
220                 }
221
222                 spin_lock(&nilfs->ns_last_segment_lock);
223                 nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
224                 spin_unlock(&nilfs->ns_last_segment_lock);
225         }
226  out:
227         return err;
228 }
229
230 void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
231                           struct the_nilfs *nilfs)
232 {
233         sector_t nfreeblocks;
234
235         /* nilfs->ns_sem must be locked by the caller. */
236         nilfs_count_free_blocks(nilfs, &nfreeblocks);
237         sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
238
239         spin_lock(&nilfs->ns_last_segment_lock);
240         sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
241         sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
242         sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
243         spin_unlock(&nilfs->ns_last_segment_lock);
244 }
245
246 struct nilfs_super_block **nilfs_prepare_super(struct super_block *sb,
247                                                int flip)
248 {
249         struct the_nilfs *nilfs = sb->s_fs_info;
250         struct nilfs_super_block **sbp = nilfs->ns_sbp;
251
252         /* nilfs->ns_sem must be locked by the caller. */
253         if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
254                 if (sbp[1] &&
255                     sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
256                         memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
257                 } else {
258                         nilfs_crit(sb, "superblock broke");
259                         return NULL;
260                 }
261         } else if (sbp[1] &&
262                    sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
263                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
264         }
265
266         if (flip && sbp[1])
267                 nilfs_swap_super_block(nilfs);
268
269         return sbp;
270 }
271
272 int nilfs_commit_super(struct super_block *sb, int flag)
273 {
274         struct the_nilfs *nilfs = sb->s_fs_info;
275         struct nilfs_super_block **sbp = nilfs->ns_sbp;
276         time64_t t;
277
278         /* nilfs->ns_sem must be locked by the caller. */
279         t = ktime_get_real_seconds();
280         nilfs->ns_sbwtime = t;
281         sbp[0]->s_wtime = cpu_to_le64(t);
282         sbp[0]->s_sum = 0;
283         sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
284                                              (unsigned char *)sbp[0],
285                                              nilfs->ns_sbsize));
286         if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
287                 sbp[1]->s_wtime = sbp[0]->s_wtime;
288                 sbp[1]->s_sum = 0;
289                 sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
290                                             (unsigned char *)sbp[1],
291                                             nilfs->ns_sbsize));
292         }
293         clear_nilfs_sb_dirty(nilfs);
294         nilfs->ns_flushed_device = 1;
295         /* make sure store to ns_flushed_device cannot be reordered */
296         smp_wmb();
297         return nilfs_sync_super(sb, flag);
298 }
299
300 /**
301  * nilfs_cleanup_super() - write filesystem state for cleanup
302  * @sb: super block instance to be unmounted or degraded to read-only
303  *
304  * This function restores state flags in the on-disk super block.
305  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
306  * filesystem was not clean previously.
307  */
308 int nilfs_cleanup_super(struct super_block *sb)
309 {
310         struct the_nilfs *nilfs = sb->s_fs_info;
311         struct nilfs_super_block **sbp;
312         int flag = NILFS_SB_COMMIT;
313         int ret = -EIO;
314
315         sbp = nilfs_prepare_super(sb, 0);
316         if (sbp) {
317                 sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
318                 nilfs_set_log_cursor(sbp[0], nilfs);
319                 if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
320                         /*
321                          * make the "clean" flag also to the opposite
322                          * super block if both super blocks point to
323                          * the same checkpoint.
324                          */
325                         sbp[1]->s_state = sbp[0]->s_state;
326                         flag = NILFS_SB_COMMIT_ALL;
327                 }
328                 ret = nilfs_commit_super(sb, flag);
329         }
330         return ret;
331 }
332
333 /**
334  * nilfs_move_2nd_super - relocate secondary super block
335  * @sb: super block instance
336  * @sb2off: new offset of the secondary super block (in bytes)
337  */
338 static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
339 {
340         struct the_nilfs *nilfs = sb->s_fs_info;
341         struct buffer_head *nsbh;
342         struct nilfs_super_block *nsbp;
343         sector_t blocknr, newblocknr;
344         unsigned long offset;
345         int sb2i;  /* array index of the secondary superblock */
346         int ret = 0;
347
348         /* nilfs->ns_sem must be locked by the caller. */
349         if (nilfs->ns_sbh[1] &&
350             nilfs->ns_sbh[1]->b_blocknr > nilfs->ns_first_data_block) {
351                 sb2i = 1;
352                 blocknr = nilfs->ns_sbh[1]->b_blocknr;
353         } else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
354                 sb2i = 0;
355                 blocknr = nilfs->ns_sbh[0]->b_blocknr;
356         } else {
357                 sb2i = -1;
358                 blocknr = 0;
359         }
360         if (sb2i >= 0 && (u64)blocknr << nilfs->ns_blocksize_bits == sb2off)
361                 goto out;  /* super block location is unchanged */
362
363         /* Get new super block buffer */
364         newblocknr = sb2off >> nilfs->ns_blocksize_bits;
365         offset = sb2off & (nilfs->ns_blocksize - 1);
366         nsbh = sb_getblk(sb, newblocknr);
367         if (!nsbh) {
368                 nilfs_warn(sb,
369                            "unable to move secondary superblock to block %llu",
370                            (unsigned long long)newblocknr);
371                 ret = -EIO;
372                 goto out;
373         }
374         nsbp = (void *)nsbh->b_data + offset;
375         memset(nsbp, 0, nilfs->ns_blocksize);
376
377         if (sb2i >= 0) {
378                 memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
379                 brelse(nilfs->ns_sbh[sb2i]);
380                 nilfs->ns_sbh[sb2i] = nsbh;
381                 nilfs->ns_sbp[sb2i] = nsbp;
382         } else if (nilfs->ns_sbh[0]->b_blocknr < nilfs->ns_first_data_block) {
383                 /* secondary super block will be restored to index 1 */
384                 nilfs->ns_sbh[1] = nsbh;
385                 nilfs->ns_sbp[1] = nsbp;
386         } else {
387                 brelse(nsbh);
388         }
389 out:
390         return ret;
391 }
392
393 /**
394  * nilfs_resize_fs - resize the filesystem
395  * @sb: super block instance
396  * @newsize: new size of the filesystem (in bytes)
397  */
398 int nilfs_resize_fs(struct super_block *sb, __u64 newsize)
399 {
400         struct the_nilfs *nilfs = sb->s_fs_info;
401         struct nilfs_super_block **sbp;
402         __u64 devsize, newnsegs;
403         loff_t sb2off;
404         int ret;
405
406         ret = -ERANGE;
407         devsize = bdev_nr_bytes(sb->s_bdev);
408         if (newsize > devsize)
409                 goto out;
410
411         /*
412          * Write lock is required to protect some functions depending
413          * on the number of segments, the number of reserved segments,
414          * and so forth.
415          */
416         down_write(&nilfs->ns_segctor_sem);
417
418         sb2off = NILFS_SB2_OFFSET_BYTES(newsize);
419         newnsegs = sb2off >> nilfs->ns_blocksize_bits;
420         do_div(newnsegs, nilfs->ns_blocks_per_segment);
421
422         ret = nilfs_sufile_resize(nilfs->ns_sufile, newnsegs);
423         up_write(&nilfs->ns_segctor_sem);
424         if (ret < 0)
425                 goto out;
426
427         ret = nilfs_construct_segment(sb);
428         if (ret < 0)
429                 goto out;
430
431         down_write(&nilfs->ns_sem);
432         nilfs_move_2nd_super(sb, sb2off);
433         ret = -EIO;
434         sbp = nilfs_prepare_super(sb, 0);
435         if (likely(sbp)) {
436                 nilfs_set_log_cursor(sbp[0], nilfs);
437                 /*
438                  * Drop NILFS_RESIZE_FS flag for compatibility with
439                  * mount-time resize which may be implemented in a
440                  * future release.
441                  */
442                 sbp[0]->s_state = cpu_to_le16(le16_to_cpu(sbp[0]->s_state) &
443                                               ~NILFS_RESIZE_FS);
444                 sbp[0]->s_dev_size = cpu_to_le64(newsize);
445                 sbp[0]->s_nsegments = cpu_to_le64(nilfs->ns_nsegments);
446                 if (sbp[1])
447                         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
448                 ret = nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
449         }
450         up_write(&nilfs->ns_sem);
451
452         /*
453          * Reset the range of allocatable segments last.  This order
454          * is important in the case of expansion because the secondary
455          * superblock must be protected from log write until migration
456          * completes.
457          */
458         if (!ret)
459                 nilfs_sufile_set_alloc_range(nilfs->ns_sufile, 0, newnsegs - 1);
460 out:
461         return ret;
462 }
463
464 static void nilfs_put_super(struct super_block *sb)
465 {
466         struct the_nilfs *nilfs = sb->s_fs_info;
467
468         nilfs_detach_log_writer(sb);
469
470         if (!sb_rdonly(sb)) {
471                 down_write(&nilfs->ns_sem);
472                 nilfs_cleanup_super(sb);
473                 up_write(&nilfs->ns_sem);
474         }
475
476         iput(nilfs->ns_sufile);
477         iput(nilfs->ns_cpfile);
478         iput(nilfs->ns_dat);
479
480         destroy_nilfs(nilfs);
481         sb->s_fs_info = NULL;
482 }
483
484 static int nilfs_sync_fs(struct super_block *sb, int wait)
485 {
486         struct the_nilfs *nilfs = sb->s_fs_info;
487         struct nilfs_super_block **sbp;
488         int err = 0;
489
490         /* This function is called when super block should be written back */
491         if (wait)
492                 err = nilfs_construct_segment(sb);
493
494         down_write(&nilfs->ns_sem);
495         if (nilfs_sb_dirty(nilfs)) {
496                 sbp = nilfs_prepare_super(sb, nilfs_sb_will_flip(nilfs));
497                 if (likely(sbp)) {
498                         nilfs_set_log_cursor(sbp[0], nilfs);
499                         nilfs_commit_super(sb, NILFS_SB_COMMIT);
500                 }
501         }
502         up_write(&nilfs->ns_sem);
503
504         if (!err)
505                 err = nilfs_flush_device(nilfs);
506
507         return err;
508 }
509
510 int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
511                             struct nilfs_root **rootp)
512 {
513         struct the_nilfs *nilfs = sb->s_fs_info;
514         struct nilfs_root *root;
515         struct nilfs_checkpoint *raw_cp;
516         struct buffer_head *bh_cp;
517         int err = -ENOMEM;
518
519         root = nilfs_find_or_create_root(
520                 nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
521         if (!root)
522                 return err;
523
524         if (root->ifile)
525                 goto reuse; /* already attached checkpoint */
526
527         down_read(&nilfs->ns_segctor_sem);
528         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
529                                           &bh_cp);
530         up_read(&nilfs->ns_segctor_sem);
531         if (unlikely(err)) {
532                 if (err == -ENOENT || err == -EINVAL) {
533                         nilfs_err(sb,
534                                   "Invalid checkpoint (checkpoint number=%llu)",
535                                   (unsigned long long)cno);
536                         err = -EINVAL;
537                 }
538                 goto failed;
539         }
540
541         err = nilfs_ifile_read(sb, root, nilfs->ns_inode_size,
542                                &raw_cp->cp_ifile_inode, &root->ifile);
543         if (err)
544                 goto failed_bh;
545
546         atomic64_set(&root->inodes_count,
547                         le64_to_cpu(raw_cp->cp_inodes_count));
548         atomic64_set(&root->blocks_count,
549                         le64_to_cpu(raw_cp->cp_blocks_count));
550
551         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
552
553  reuse:
554         *rootp = root;
555         return 0;
556
557  failed_bh:
558         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
559  failed:
560         nilfs_put_root(root);
561
562         return err;
563 }
564
565 static int nilfs_freeze(struct super_block *sb)
566 {
567         struct the_nilfs *nilfs = sb->s_fs_info;
568         int err;
569
570         if (sb_rdonly(sb))
571                 return 0;
572
573         /* Mark super block clean */
574         down_write(&nilfs->ns_sem);
575         err = nilfs_cleanup_super(sb);
576         up_write(&nilfs->ns_sem);
577         return err;
578 }
579
580 static int nilfs_unfreeze(struct super_block *sb)
581 {
582         struct the_nilfs *nilfs = sb->s_fs_info;
583
584         if (sb_rdonly(sb))
585                 return 0;
586
587         down_write(&nilfs->ns_sem);
588         nilfs_setup_super(sb, false);
589         up_write(&nilfs->ns_sem);
590         return 0;
591 }
592
593 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
594 {
595         struct super_block *sb = dentry->d_sb;
596         struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
597         struct the_nilfs *nilfs = root->nilfs;
598         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
599         unsigned long long blocks;
600         unsigned long overhead;
601         unsigned long nrsvblocks;
602         sector_t nfreeblocks;
603         u64 nmaxinodes, nfreeinodes;
604         int err;
605
606         /*
607          * Compute all of the segment blocks
608          *
609          * The blocks before first segment and after last segment
610          * are excluded.
611          */
612         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
613                 - nilfs->ns_first_data_block;
614         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
615
616         /*
617          * Compute the overhead
618          *
619          * When distributing meta data blocks outside segment structure,
620          * We must count them as the overhead.
621          */
622         overhead = 0;
623
624         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
625         if (unlikely(err))
626                 return err;
627
628         err = nilfs_ifile_count_free_inodes(root->ifile,
629                                             &nmaxinodes, &nfreeinodes);
630         if (unlikely(err)) {
631                 nilfs_warn(sb, "failed to count free inodes: err=%d", err);
632                 if (err == -ERANGE) {
633                         /*
634                          * If nilfs_palloc_count_max_entries() returns
635                          * -ERANGE error code then we simply treat
636                          * curent inodes count as maximum possible and
637                          * zero as free inodes value.
638                          */
639                         nmaxinodes = atomic64_read(&root->inodes_count);
640                         nfreeinodes = 0;
641                         err = 0;
642                 } else
643                         return err;
644         }
645
646         buf->f_type = NILFS_SUPER_MAGIC;
647         buf->f_bsize = sb->s_blocksize;
648         buf->f_blocks = blocks - overhead;
649         buf->f_bfree = nfreeblocks;
650         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
651                 (buf->f_bfree - nrsvblocks) : 0;
652         buf->f_files = nmaxinodes;
653         buf->f_ffree = nfreeinodes;
654         buf->f_namelen = NILFS_NAME_LEN;
655         buf->f_fsid = u64_to_fsid(id);
656
657         return 0;
658 }
659
660 static int nilfs_show_options(struct seq_file *seq, struct dentry *dentry)
661 {
662         struct super_block *sb = dentry->d_sb;
663         struct the_nilfs *nilfs = sb->s_fs_info;
664         struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
665
666         if (!nilfs_test_opt(nilfs, BARRIER))
667                 seq_puts(seq, ",nobarrier");
668         if (root->cno != NILFS_CPTREE_CURRENT_CNO)
669                 seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
670         if (nilfs_test_opt(nilfs, ERRORS_PANIC))
671                 seq_puts(seq, ",errors=panic");
672         if (nilfs_test_opt(nilfs, ERRORS_CONT))
673                 seq_puts(seq, ",errors=continue");
674         if (nilfs_test_opt(nilfs, STRICT_ORDER))
675                 seq_puts(seq, ",order=strict");
676         if (nilfs_test_opt(nilfs, NORECOVERY))
677                 seq_puts(seq, ",norecovery");
678         if (nilfs_test_opt(nilfs, DISCARD))
679                 seq_puts(seq, ",discard");
680
681         return 0;
682 }
683
684 static const struct super_operations nilfs_sops = {
685         .alloc_inode    = nilfs_alloc_inode,
686         .free_inode     = nilfs_free_inode,
687         .dirty_inode    = nilfs_dirty_inode,
688         .evict_inode    = nilfs_evict_inode,
689         .put_super      = nilfs_put_super,
690         .sync_fs        = nilfs_sync_fs,
691         .freeze_fs      = nilfs_freeze,
692         .unfreeze_fs    = nilfs_unfreeze,
693         .statfs         = nilfs_statfs,
694         .remount_fs     = nilfs_remount,
695         .show_options = nilfs_show_options
696 };
697
698 enum {
699         Opt_err_cont, Opt_err_panic, Opt_err_ro,
700         Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
701         Opt_discard, Opt_nodiscard, Opt_err,
702 };
703
704 static match_table_t tokens = {
705         {Opt_err_cont, "errors=continue"},
706         {Opt_err_panic, "errors=panic"},
707         {Opt_err_ro, "errors=remount-ro"},
708         {Opt_barrier, "barrier"},
709         {Opt_nobarrier, "nobarrier"},
710         {Opt_snapshot, "cp=%u"},
711         {Opt_order, "order=%s"},
712         {Opt_norecovery, "norecovery"},
713         {Opt_discard, "discard"},
714         {Opt_nodiscard, "nodiscard"},
715         {Opt_err, NULL}
716 };
717
718 static int parse_options(char *options, struct super_block *sb, int is_remount)
719 {
720         struct the_nilfs *nilfs = sb->s_fs_info;
721         char *p;
722         substring_t args[MAX_OPT_ARGS];
723
724         if (!options)
725                 return 1;
726
727         while ((p = strsep(&options, ",")) != NULL) {
728                 int token;
729
730                 if (!*p)
731                         continue;
732
733                 token = match_token(p, tokens, args);
734                 switch (token) {
735                 case Opt_barrier:
736                         nilfs_set_opt(nilfs, BARRIER);
737                         break;
738                 case Opt_nobarrier:
739                         nilfs_clear_opt(nilfs, BARRIER);
740                         break;
741                 case Opt_order:
742                         if (strcmp(args[0].from, "relaxed") == 0)
743                                 /* Ordered data semantics */
744                                 nilfs_clear_opt(nilfs, STRICT_ORDER);
745                         else if (strcmp(args[0].from, "strict") == 0)
746                                 /* Strict in-order semantics */
747                                 nilfs_set_opt(nilfs, STRICT_ORDER);
748                         else
749                                 return 0;
750                         break;
751                 case Opt_err_panic:
752                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_PANIC);
753                         break;
754                 case Opt_err_ro:
755                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_RO);
756                         break;
757                 case Opt_err_cont:
758                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_CONT);
759                         break;
760                 case Opt_snapshot:
761                         if (is_remount) {
762                                 nilfs_err(sb,
763                                           "\"%s\" option is invalid for remount",
764                                           p);
765                                 return 0;
766                         }
767                         break;
768                 case Opt_norecovery:
769                         nilfs_set_opt(nilfs, NORECOVERY);
770                         break;
771                 case Opt_discard:
772                         nilfs_set_opt(nilfs, DISCARD);
773                         break;
774                 case Opt_nodiscard:
775                         nilfs_clear_opt(nilfs, DISCARD);
776                         break;
777                 default:
778                         nilfs_err(sb, "unrecognized mount option \"%s\"", p);
779                         return 0;
780                 }
781         }
782         return 1;
783 }
784
785 static inline void
786 nilfs_set_default_options(struct super_block *sb,
787                           struct nilfs_super_block *sbp)
788 {
789         struct the_nilfs *nilfs = sb->s_fs_info;
790
791         nilfs->ns_mount_opt =
792                 NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
793 }
794
795 static int nilfs_setup_super(struct super_block *sb, int is_mount)
796 {
797         struct the_nilfs *nilfs = sb->s_fs_info;
798         struct nilfs_super_block **sbp;
799         int max_mnt_count;
800         int mnt_count;
801
802         /* nilfs->ns_sem must be locked by the caller. */
803         sbp = nilfs_prepare_super(sb, 0);
804         if (!sbp)
805                 return -EIO;
806
807         if (!is_mount)
808                 goto skip_mount_setup;
809
810         max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
811         mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
812
813         if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
814                 nilfs_warn(sb, "mounting fs with errors");
815 #if 0
816         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
817                 nilfs_warn(sb, "maximal mount count reached");
818 #endif
819         }
820         if (!max_mnt_count)
821                 sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
822
823         sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
824         sbp[0]->s_mtime = cpu_to_le64(ktime_get_real_seconds());
825
826 skip_mount_setup:
827         sbp[0]->s_state =
828                 cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
829         /* synchronize sbp[1] with sbp[0] */
830         if (sbp[1])
831                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
832         return nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
833 }
834
835 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
836                                                  u64 pos, int blocksize,
837                                                  struct buffer_head **pbh)
838 {
839         unsigned long long sb_index = pos;
840         unsigned long offset;
841
842         offset = do_div(sb_index, blocksize);
843         *pbh = sb_bread(sb, sb_index);
844         if (!*pbh)
845                 return NULL;
846         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
847 }
848
849 int nilfs_store_magic_and_option(struct super_block *sb,
850                                  struct nilfs_super_block *sbp,
851                                  char *data)
852 {
853         struct the_nilfs *nilfs = sb->s_fs_info;
854
855         sb->s_magic = le16_to_cpu(sbp->s_magic);
856
857         /* FS independent flags */
858 #ifdef NILFS_ATIME_DISABLE
859         sb->s_flags |= SB_NOATIME;
860 #endif
861
862         nilfs_set_default_options(sb, sbp);
863
864         nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
865         nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
866         nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
867         nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
868
869         return !parse_options(data, sb, 0) ? -EINVAL : 0;
870 }
871
872 int nilfs_check_feature_compatibility(struct super_block *sb,
873                                       struct nilfs_super_block *sbp)
874 {
875         __u64 features;
876
877         features = le64_to_cpu(sbp->s_feature_incompat) &
878                 ~NILFS_FEATURE_INCOMPAT_SUPP;
879         if (features) {
880                 nilfs_err(sb,
881                           "couldn't mount because of unsupported optional features (%llx)",
882                           (unsigned long long)features);
883                 return -EINVAL;
884         }
885         features = le64_to_cpu(sbp->s_feature_compat_ro) &
886                 ~NILFS_FEATURE_COMPAT_RO_SUPP;
887         if (!sb_rdonly(sb) && features) {
888                 nilfs_err(sb,
889                           "couldn't mount RDWR because of unsupported optional features (%llx)",
890                           (unsigned long long)features);
891                 return -EINVAL;
892         }
893         return 0;
894 }
895
896 static int nilfs_get_root_dentry(struct super_block *sb,
897                                  struct nilfs_root *root,
898                                  struct dentry **root_dentry)
899 {
900         struct inode *inode;
901         struct dentry *dentry;
902         int ret = 0;
903
904         inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
905         if (IS_ERR(inode)) {
906                 ret = PTR_ERR(inode);
907                 nilfs_err(sb, "error %d getting root inode", ret);
908                 goto out;
909         }
910         if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
911                 iput(inode);
912                 nilfs_err(sb, "corrupt root inode");
913                 ret = -EINVAL;
914                 goto out;
915         }
916
917         if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
918                 dentry = d_find_alias(inode);
919                 if (!dentry) {
920                         dentry = d_make_root(inode);
921                         if (!dentry) {
922                                 ret = -ENOMEM;
923                                 goto failed_dentry;
924                         }
925                 } else {
926                         iput(inode);
927                 }
928         } else {
929                 dentry = d_obtain_root(inode);
930                 if (IS_ERR(dentry)) {
931                         ret = PTR_ERR(dentry);
932                         goto failed_dentry;
933                 }
934         }
935         *root_dentry = dentry;
936  out:
937         return ret;
938
939  failed_dentry:
940         nilfs_err(sb, "error %d getting root dentry", ret);
941         goto out;
942 }
943
944 static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
945                                  struct dentry **root_dentry)
946 {
947         struct the_nilfs *nilfs = s->s_fs_info;
948         struct nilfs_root *root;
949         int ret;
950
951         mutex_lock(&nilfs->ns_snapshot_mount_mutex);
952
953         down_read(&nilfs->ns_segctor_sem);
954         ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
955         up_read(&nilfs->ns_segctor_sem);
956         if (ret < 0) {
957                 ret = (ret == -ENOENT) ? -EINVAL : ret;
958                 goto out;
959         } else if (!ret) {
960                 nilfs_err(s,
961                           "The specified checkpoint is not a snapshot (checkpoint number=%llu)",
962                           (unsigned long long)cno);
963                 ret = -EINVAL;
964                 goto out;
965         }
966
967         ret = nilfs_attach_checkpoint(s, cno, false, &root);
968         if (ret) {
969                 nilfs_err(s,
970                           "error %d while loading snapshot (checkpoint number=%llu)",
971                           ret, (unsigned long long)cno);
972                 goto out;
973         }
974         ret = nilfs_get_root_dentry(s, root, root_dentry);
975         nilfs_put_root(root);
976  out:
977         mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
978         return ret;
979 }
980
981 /**
982  * nilfs_tree_is_busy() - try to shrink dentries of a checkpoint
983  * @root_dentry: root dentry of the tree to be shrunk
984  *
985  * This function returns true if the tree was in-use.
986  */
987 static bool nilfs_tree_is_busy(struct dentry *root_dentry)
988 {
989         shrink_dcache_parent(root_dentry);
990         return d_count(root_dentry) > 1;
991 }
992
993 int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
994 {
995         struct the_nilfs *nilfs = sb->s_fs_info;
996         struct nilfs_root *root;
997         struct inode *inode;
998         struct dentry *dentry;
999         int ret;
1000
1001         if (cno > nilfs->ns_cno)
1002                 return false;
1003
1004         if (cno >= nilfs_last_cno(nilfs))
1005                 return true;    /* protect recent checkpoints */
1006
1007         ret = false;
1008         root = nilfs_lookup_root(nilfs, cno);
1009         if (root) {
1010                 inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
1011                 if (inode) {
1012                         dentry = d_find_alias(inode);
1013                         if (dentry) {
1014                                 ret = nilfs_tree_is_busy(dentry);
1015                                 dput(dentry);
1016                         }
1017                         iput(inode);
1018                 }
1019                 nilfs_put_root(root);
1020         }
1021         return ret;
1022 }
1023
1024 /**
1025  * nilfs_fill_super() - initialize a super block instance
1026  * @sb: super_block
1027  * @data: mount options
1028  * @silent: silent mode flag
1029  *
1030  * This function is called exclusively by nilfs->ns_mount_mutex.
1031  * So, the recovery process is protected from other simultaneous mounts.
1032  */
1033 static int
1034 nilfs_fill_super(struct super_block *sb, void *data, int silent)
1035 {
1036         struct the_nilfs *nilfs;
1037         struct nilfs_root *fsroot;
1038         __u64 cno;
1039         int err;
1040
1041         nilfs = alloc_nilfs(sb);
1042         if (!nilfs)
1043                 return -ENOMEM;
1044
1045         sb->s_fs_info = nilfs;
1046
1047         err = init_nilfs(nilfs, sb, (char *)data);
1048         if (err)
1049                 goto failed_nilfs;
1050
1051         sb->s_op = &nilfs_sops;
1052         sb->s_export_op = &nilfs_export_ops;
1053         sb->s_root = NULL;
1054         sb->s_time_gran = 1;
1055         sb->s_max_links = NILFS_LINK_MAX;
1056
1057         sb->s_bdi = bdi_get(sb->s_bdev->bd_disk->bdi);
1058
1059         err = load_nilfs(nilfs, sb);
1060         if (err)
1061                 goto failed_nilfs;
1062
1063         cno = nilfs_last_cno(nilfs);
1064         err = nilfs_attach_checkpoint(sb, cno, true, &fsroot);
1065         if (err) {
1066                 nilfs_err(sb,
1067                           "error %d while loading last checkpoint (checkpoint number=%llu)",
1068                           err, (unsigned long long)cno);
1069                 goto failed_unload;
1070         }
1071
1072         if (!sb_rdonly(sb)) {
1073                 err = nilfs_attach_log_writer(sb, fsroot);
1074                 if (err)
1075                         goto failed_checkpoint;
1076         }
1077
1078         err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
1079         if (err)
1080                 goto failed_segctor;
1081
1082         nilfs_put_root(fsroot);
1083
1084         if (!sb_rdonly(sb)) {
1085                 down_write(&nilfs->ns_sem);
1086                 nilfs_setup_super(sb, true);
1087                 up_write(&nilfs->ns_sem);
1088         }
1089
1090         return 0;
1091
1092  failed_segctor:
1093         nilfs_detach_log_writer(sb);
1094
1095  failed_checkpoint:
1096         nilfs_put_root(fsroot);
1097
1098  failed_unload:
1099         iput(nilfs->ns_sufile);
1100         iput(nilfs->ns_cpfile);
1101         iput(nilfs->ns_dat);
1102
1103  failed_nilfs:
1104         destroy_nilfs(nilfs);
1105         return err;
1106 }
1107
1108 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
1109 {
1110         struct the_nilfs *nilfs = sb->s_fs_info;
1111         unsigned long old_sb_flags;
1112         unsigned long old_mount_opt;
1113         int err;
1114
1115         sync_filesystem(sb);
1116         old_sb_flags = sb->s_flags;
1117         old_mount_opt = nilfs->ns_mount_opt;
1118
1119         if (!parse_options(data, sb, 1)) {
1120                 err = -EINVAL;
1121                 goto restore_opts;
1122         }
1123         sb->s_flags = (sb->s_flags & ~SB_POSIXACL);
1124
1125         err = -EINVAL;
1126
1127         if (!nilfs_valid_fs(nilfs)) {
1128                 nilfs_warn(sb,
1129                            "couldn't remount because the filesystem is in an incomplete recovery state");
1130                 goto restore_opts;
1131         }
1132
1133         if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1134                 goto out;
1135         if (*flags & SB_RDONLY) {
1136                 /* Shutting down log writer */
1137                 nilfs_detach_log_writer(sb);
1138                 sb->s_flags |= SB_RDONLY;
1139
1140                 /*
1141                  * Remounting a valid RW partition RDONLY, so set
1142                  * the RDONLY flag and then mark the partition as valid again.
1143                  */
1144                 down_write(&nilfs->ns_sem);
1145                 nilfs_cleanup_super(sb);
1146                 up_write(&nilfs->ns_sem);
1147         } else {
1148                 __u64 features;
1149                 struct nilfs_root *root;
1150
1151                 /*
1152                  * Mounting a RDONLY partition read-write, so reread and
1153                  * store the current valid flag.  (It may have been changed
1154                  * by fsck since we originally mounted the partition.)
1155                  */
1156                 down_read(&nilfs->ns_sem);
1157                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1158                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
1159                 up_read(&nilfs->ns_sem);
1160                 if (features) {
1161                         nilfs_warn(sb,
1162                                    "couldn't remount RDWR because of unsupported optional features (%llx)",
1163                                    (unsigned long long)features);
1164                         err = -EROFS;
1165                         goto restore_opts;
1166                 }
1167
1168                 sb->s_flags &= ~SB_RDONLY;
1169
1170                 root = NILFS_I(d_inode(sb->s_root))->i_root;
1171                 err = nilfs_attach_log_writer(sb, root);
1172                 if (err)
1173                         goto restore_opts;
1174
1175                 down_write(&nilfs->ns_sem);
1176                 nilfs_setup_super(sb, true);
1177                 up_write(&nilfs->ns_sem);
1178         }
1179  out:
1180         return 0;
1181
1182  restore_opts:
1183         sb->s_flags = old_sb_flags;
1184         nilfs->ns_mount_opt = old_mount_opt;
1185         return err;
1186 }
1187
1188 struct nilfs_super_data {
1189         struct block_device *bdev;
1190         __u64 cno;
1191         int flags;
1192 };
1193
1194 static int nilfs_parse_snapshot_option(const char *option,
1195                                        const substring_t *arg,
1196                                        struct nilfs_super_data *sd)
1197 {
1198         unsigned long long val;
1199         const char *msg = NULL;
1200         int err;
1201
1202         if (!(sd->flags & SB_RDONLY)) {
1203                 msg = "read-only option is not specified";
1204                 goto parse_error;
1205         }
1206
1207         err = kstrtoull(arg->from, 0, &val);
1208         if (err) {
1209                 if (err == -ERANGE)
1210                         msg = "too large checkpoint number";
1211                 else
1212                         msg = "malformed argument";
1213                 goto parse_error;
1214         } else if (val == 0) {
1215                 msg = "invalid checkpoint number 0";
1216                 goto parse_error;
1217         }
1218         sd->cno = val;
1219         return 0;
1220
1221 parse_error:
1222         nilfs_err(NULL, "invalid option \"%s\": %s", option, msg);
1223         return 1;
1224 }
1225
1226 /**
1227  * nilfs_identify - pre-read mount options needed to identify mount instance
1228  * @data: mount options
1229  * @sd: nilfs_super_data
1230  */
1231 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1232 {
1233         char *p, *options = data;
1234         substring_t args[MAX_OPT_ARGS];
1235         int token;
1236         int ret = 0;
1237
1238         do {
1239                 p = strsep(&options, ",");
1240                 if (p != NULL && *p) {
1241                         token = match_token(p, tokens, args);
1242                         if (token == Opt_snapshot)
1243                                 ret = nilfs_parse_snapshot_option(p, &args[0],
1244                                                                   sd);
1245                 }
1246                 if (!options)
1247                         break;
1248                 BUG_ON(options == data);
1249                 *(options - 1) = ',';
1250         } while (!ret);
1251         return ret;
1252 }
1253
1254 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1255 {
1256         s->s_bdev = data;
1257         s->s_dev = s->s_bdev->bd_dev;
1258         return 0;
1259 }
1260
1261 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1262 {
1263         return (void *)s->s_bdev == data;
1264 }
1265
1266 static struct dentry *
1267 nilfs_mount(struct file_system_type *fs_type, int flags,
1268              const char *dev_name, void *data)
1269 {
1270         struct nilfs_super_data sd;
1271         struct super_block *s;
1272         fmode_t mode = FMODE_READ | FMODE_EXCL;
1273         struct dentry *root_dentry;
1274         int err, s_new = false;
1275
1276         if (!(flags & SB_RDONLY))
1277                 mode |= FMODE_WRITE;
1278
1279         sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
1280         if (IS_ERR(sd.bdev))
1281                 return ERR_CAST(sd.bdev);
1282
1283         sd.cno = 0;
1284         sd.flags = flags;
1285         if (nilfs_identify((char *)data, &sd)) {
1286                 err = -EINVAL;
1287                 goto failed;
1288         }
1289
1290         /*
1291          * once the super is inserted into the list by sget, s_umount
1292          * will protect the lockfs code from trying to start a snapshot
1293          * while we are mounting
1294          */
1295         mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
1296         if (sd.bdev->bd_fsfreeze_count > 0) {
1297                 mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1298                 err = -EBUSY;
1299                 goto failed;
1300         }
1301         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, flags,
1302                  sd.bdev);
1303         mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1304         if (IS_ERR(s)) {
1305                 err = PTR_ERR(s);
1306                 goto failed;
1307         }
1308
1309         if (!s->s_root) {
1310                 s_new = true;
1311
1312                 /* New superblock instance created */
1313                 s->s_mode = mode;
1314                 snprintf(s->s_id, sizeof(s->s_id), "%pg", sd.bdev);
1315                 sb_set_blocksize(s, block_size(sd.bdev));
1316
1317                 err = nilfs_fill_super(s, data, flags & SB_SILENT ? 1 : 0);
1318                 if (err)
1319                         goto failed_super;
1320
1321                 s->s_flags |= SB_ACTIVE;
1322         } else if (!sd.cno) {
1323                 if (nilfs_tree_is_busy(s->s_root)) {
1324                         if ((flags ^ s->s_flags) & SB_RDONLY) {
1325                                 nilfs_err(s,
1326                                           "the device already has a %s mount.",
1327                                           sb_rdonly(s) ? "read-only" : "read/write");
1328                                 err = -EBUSY;
1329                                 goto failed_super;
1330                         }
1331                 } else {
1332                         /*
1333                          * Try remount to setup mount states if the current
1334                          * tree is not mounted and only snapshots use this sb.
1335                          */
1336                         err = nilfs_remount(s, &flags, data);
1337                         if (err)
1338                                 goto failed_super;
1339                 }
1340         }
1341
1342         if (sd.cno) {
1343                 err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
1344                 if (err)
1345                         goto failed_super;
1346         } else {
1347                 root_dentry = dget(s->s_root);
1348         }
1349
1350         if (!s_new)
1351                 blkdev_put(sd.bdev, mode);
1352
1353         return root_dentry;
1354
1355  failed_super:
1356         deactivate_locked_super(s);
1357
1358  failed:
1359         if (!s_new)
1360                 blkdev_put(sd.bdev, mode);
1361         return ERR_PTR(err);
1362 }
1363
1364 struct file_system_type nilfs_fs_type = {
1365         .owner    = THIS_MODULE,
1366         .name     = "nilfs2",
1367         .mount    = nilfs_mount,
1368         .kill_sb  = kill_block_super,
1369         .fs_flags = FS_REQUIRES_DEV,
1370 };
1371 MODULE_ALIAS_FS("nilfs2");
1372
1373 static void nilfs_inode_init_once(void *obj)
1374 {
1375         struct nilfs_inode_info *ii = obj;
1376
1377         INIT_LIST_HEAD(&ii->i_dirty);
1378 #ifdef CONFIG_NILFS_XATTR
1379         init_rwsem(&ii->xattr_sem);
1380 #endif
1381         inode_init_once(&ii->vfs_inode);
1382 }
1383
1384 static void nilfs_segbuf_init_once(void *obj)
1385 {
1386         memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1387 }
1388
1389 static void nilfs_destroy_cachep(void)
1390 {
1391         /*
1392          * Make sure all delayed rcu free inodes are flushed before we
1393          * destroy cache.
1394          */
1395         rcu_barrier();
1396
1397         kmem_cache_destroy(nilfs_inode_cachep);
1398         kmem_cache_destroy(nilfs_transaction_cachep);
1399         kmem_cache_destroy(nilfs_segbuf_cachep);
1400         kmem_cache_destroy(nilfs_btree_path_cache);
1401 }
1402
1403 static int __init nilfs_init_cachep(void)
1404 {
1405         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1406                         sizeof(struct nilfs_inode_info), 0,
1407                         SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
1408                         nilfs_inode_init_once);
1409         if (!nilfs_inode_cachep)
1410                 goto fail;
1411
1412         nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1413                         sizeof(struct nilfs_transaction_info), 0,
1414                         SLAB_RECLAIM_ACCOUNT, NULL);
1415         if (!nilfs_transaction_cachep)
1416                 goto fail;
1417
1418         nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1419                         sizeof(struct nilfs_segment_buffer), 0,
1420                         SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1421         if (!nilfs_segbuf_cachep)
1422                 goto fail;
1423
1424         nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1425                         sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1426                         0, 0, NULL);
1427         if (!nilfs_btree_path_cache)
1428                 goto fail;
1429
1430         return 0;
1431
1432 fail:
1433         nilfs_destroy_cachep();
1434         return -ENOMEM;
1435 }
1436
1437 static int __init init_nilfs_fs(void)
1438 {
1439         int err;
1440
1441         err = nilfs_init_cachep();
1442         if (err)
1443                 goto fail;
1444
1445         err = nilfs_sysfs_init();
1446         if (err)
1447                 goto free_cachep;
1448
1449         err = register_filesystem(&nilfs_fs_type);
1450         if (err)
1451                 goto deinit_sysfs_entry;
1452
1453         printk(KERN_INFO "NILFS version 2 loaded\n");
1454         return 0;
1455
1456 deinit_sysfs_entry:
1457         nilfs_sysfs_exit();
1458 free_cachep:
1459         nilfs_destroy_cachep();
1460 fail:
1461         return err;
1462 }
1463
1464 static void __exit exit_nilfs_fs(void)
1465 {
1466         nilfs_destroy_cachep();
1467         nilfs_sysfs_exit();
1468         unregister_filesystem(&nilfs_fs_type);
1469 }
1470
1471 module_init(init_nilfs_fs)
1472 module_exit(exit_nilfs_fs)