vmscan: fix shrinker callback bug in fs/super.c
[linux-2.6.git] / fs / nilfs2 / super.c
1 /*
2  * super.c - NILFS module and super block management.
3  *
4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
19  *
20  * Written by Ryusuke Konishi <ryusuke@osrg.net>
21  */
22 /*
23  *  linux/fs/ext2/super.c
24  *
25  * Copyright (C) 1992, 1993, 1994, 1995
26  * Remy Card (card@masi.ibp.fr)
27  * Laboratoire MASI - Institut Blaise Pascal
28  * Universite Pierre et Marie Curie (Paris VI)
29  *
30  *  from
31  *
32  *  linux/fs/minix/inode.c
33  *
34  *  Copyright (C) 1991, 1992  Linus Torvalds
35  *
36  *  Big-endian to little-endian byte-swapping/bitmaps by
37  *        David S. Miller (davem@caip.rutgers.edu), 1995
38  */
39
40 #include <linux/module.h>
41 #include <linux/string.h>
42 #include <linux/slab.h>
43 #include <linux/init.h>
44 #include <linux/blkdev.h>
45 #include <linux/parser.h>
46 #include <linux/crc32.h>
47 #include <linux/vfs.h>
48 #include <linux/writeback.h>
49 #include <linux/seq_file.h>
50 #include <linux/mount.h>
51 #include "nilfs.h"
52 #include "export.h"
53 #include "mdt.h"
54 #include "alloc.h"
55 #include "btree.h"
56 #include "btnode.h"
57 #include "page.h"
58 #include "cpfile.h"
59 #include "sufile.h" /* nilfs_sufile_resize(), nilfs_sufile_set_alloc_range() */
60 #include "ifile.h"
61 #include "dat.h"
62 #include "segment.h"
63 #include "segbuf.h"
64
65 MODULE_AUTHOR("NTT Corp.");
66 MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
67                    "(NILFS)");
68 MODULE_LICENSE("GPL");
69
70 static struct kmem_cache *nilfs_inode_cachep;
71 struct kmem_cache *nilfs_transaction_cachep;
72 struct kmem_cache *nilfs_segbuf_cachep;
73 struct kmem_cache *nilfs_btree_path_cache;
74
75 static int nilfs_setup_super(struct super_block *sb, int is_mount);
76 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
77
78 static void nilfs_set_error(struct super_block *sb)
79 {
80         struct the_nilfs *nilfs = sb->s_fs_info;
81         struct nilfs_super_block **sbp;
82
83         down_write(&nilfs->ns_sem);
84         if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
85                 nilfs->ns_mount_state |= NILFS_ERROR_FS;
86                 sbp = nilfs_prepare_super(sb, 0);
87                 if (likely(sbp)) {
88                         sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
89                         if (sbp[1])
90                                 sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
91                         nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
92                 }
93         }
94         up_write(&nilfs->ns_sem);
95 }
96
97 /**
98  * nilfs_error() - report failure condition on a filesystem
99  *
100  * nilfs_error() sets an ERROR_FS flag on the superblock as well as
101  * reporting an error message.  It should be called when NILFS detects
102  * incoherences or defects of meta data on disk.  As for sustainable
103  * errors such as a single-shot I/O error, nilfs_warning() or the printk()
104  * function should be used instead.
105  *
106  * The segment constructor must not call this function because it can
107  * kill itself.
108  */
109 void nilfs_error(struct super_block *sb, const char *function,
110                  const char *fmt, ...)
111 {
112         struct the_nilfs *nilfs = sb->s_fs_info;
113         struct va_format vaf;
114         va_list args;
115
116         va_start(args, fmt);
117
118         vaf.fmt = fmt;
119         vaf.va = &args;
120
121         printk(KERN_CRIT "NILFS error (device %s): %s: %pV\n",
122                sb->s_id, function, &vaf);
123
124         va_end(args);
125
126         if (!(sb->s_flags & MS_RDONLY)) {
127                 nilfs_set_error(sb);
128
129                 if (nilfs_test_opt(nilfs, ERRORS_RO)) {
130                         printk(KERN_CRIT "Remounting filesystem read-only\n");
131                         sb->s_flags |= MS_RDONLY;
132                 }
133         }
134
135         if (nilfs_test_opt(nilfs, ERRORS_PANIC))
136                 panic("NILFS (device %s): panic forced after error\n",
137                       sb->s_id);
138 }
139
140 void nilfs_warning(struct super_block *sb, const char *function,
141                    const char *fmt, ...)
142 {
143         struct va_format vaf;
144         va_list args;
145
146         va_start(args, fmt);
147
148         vaf.fmt = fmt;
149         vaf.va = &args;
150
151         printk(KERN_WARNING "NILFS warning (device %s): %s: %pV\n",
152                sb->s_id, function, &vaf);
153
154         va_end(args);
155 }
156
157
158 struct inode *nilfs_alloc_inode(struct super_block *sb)
159 {
160         struct nilfs_inode_info *ii;
161
162         ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
163         if (!ii)
164                 return NULL;
165         ii->i_bh = NULL;
166         ii->i_state = 0;
167         ii->i_cno = 0;
168         ii->vfs_inode.i_version = 1;
169         nilfs_mapping_init(&ii->i_btnode_cache, &ii->vfs_inode, sb->s_bdi);
170         return &ii->vfs_inode;
171 }
172
173 static void nilfs_i_callback(struct rcu_head *head)
174 {
175         struct inode *inode = container_of(head, struct inode, i_rcu);
176         struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
177
178         INIT_LIST_HEAD(&inode->i_dentry);
179
180         if (mdi) {
181                 kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
182                 kfree(mdi);
183         }
184         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
185 }
186
187 void nilfs_destroy_inode(struct inode *inode)
188 {
189         call_rcu(&inode->i_rcu, nilfs_i_callback);
190 }
191
192 static int nilfs_sync_super(struct super_block *sb, int flag)
193 {
194         struct the_nilfs *nilfs = sb->s_fs_info;
195         int err;
196
197  retry:
198         set_buffer_dirty(nilfs->ns_sbh[0]);
199         if (nilfs_test_opt(nilfs, BARRIER)) {
200                 err = __sync_dirty_buffer(nilfs->ns_sbh[0],
201                                           WRITE_SYNC | WRITE_FLUSH_FUA);
202         } else {
203                 err = sync_dirty_buffer(nilfs->ns_sbh[0]);
204         }
205
206         if (unlikely(err)) {
207                 printk(KERN_ERR
208                        "NILFS: unable to write superblock (err=%d)\n", err);
209                 if (err == -EIO && nilfs->ns_sbh[1]) {
210                         /*
211                          * sbp[0] points to newer log than sbp[1],
212                          * so copy sbp[0] to sbp[1] to take over sbp[0].
213                          */
214                         memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
215                                nilfs->ns_sbsize);
216                         nilfs_fall_back_super_block(nilfs);
217                         goto retry;
218                 }
219         } else {
220                 struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
221
222                 nilfs->ns_sbwcount++;
223
224                 /*
225                  * The latest segment becomes trailable from the position
226                  * written in superblock.
227                  */
228                 clear_nilfs_discontinued(nilfs);
229
230                 /* update GC protection for recent segments */
231                 if (nilfs->ns_sbh[1]) {
232                         if (flag == NILFS_SB_COMMIT_ALL) {
233                                 set_buffer_dirty(nilfs->ns_sbh[1]);
234                                 if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
235                                         goto out;
236                         }
237                         if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
238                             le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
239                                 sbp = nilfs->ns_sbp[1];
240                 }
241
242                 spin_lock(&nilfs->ns_last_segment_lock);
243                 nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
244                 spin_unlock(&nilfs->ns_last_segment_lock);
245         }
246  out:
247         return err;
248 }
249
250 void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
251                           struct the_nilfs *nilfs)
252 {
253         sector_t nfreeblocks;
254
255         /* nilfs->ns_sem must be locked by the caller. */
256         nilfs_count_free_blocks(nilfs, &nfreeblocks);
257         sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
258
259         spin_lock(&nilfs->ns_last_segment_lock);
260         sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
261         sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
262         sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
263         spin_unlock(&nilfs->ns_last_segment_lock);
264 }
265
266 struct nilfs_super_block **nilfs_prepare_super(struct super_block *sb,
267                                                int flip)
268 {
269         struct the_nilfs *nilfs = sb->s_fs_info;
270         struct nilfs_super_block **sbp = nilfs->ns_sbp;
271
272         /* nilfs->ns_sem must be locked by the caller. */
273         if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
274                 if (sbp[1] &&
275                     sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
276                         memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
277                 } else {
278                         printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
279                                sb->s_id);
280                         return NULL;
281                 }
282         } else if (sbp[1] &&
283                    sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
284                         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
285         }
286
287         if (flip && sbp[1])
288                 nilfs_swap_super_block(nilfs);
289
290         return sbp;
291 }
292
293 int nilfs_commit_super(struct super_block *sb, int flag)
294 {
295         struct the_nilfs *nilfs = sb->s_fs_info;
296         struct nilfs_super_block **sbp = nilfs->ns_sbp;
297         time_t t;
298
299         /* nilfs->ns_sem must be locked by the caller. */
300         t = get_seconds();
301         nilfs->ns_sbwtime = t;
302         sbp[0]->s_wtime = cpu_to_le64(t);
303         sbp[0]->s_sum = 0;
304         sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
305                                              (unsigned char *)sbp[0],
306                                              nilfs->ns_sbsize));
307         if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
308                 sbp[1]->s_wtime = sbp[0]->s_wtime;
309                 sbp[1]->s_sum = 0;
310                 sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
311                                             (unsigned char *)sbp[1],
312                                             nilfs->ns_sbsize));
313         }
314         clear_nilfs_sb_dirty(nilfs);
315         return nilfs_sync_super(sb, flag);
316 }
317
318 /**
319  * nilfs_cleanup_super() - write filesystem state for cleanup
320  * @sb: super block instance to be unmounted or degraded to read-only
321  *
322  * This function restores state flags in the on-disk super block.
323  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
324  * filesystem was not clean previously.
325  */
326 int nilfs_cleanup_super(struct super_block *sb)
327 {
328         struct the_nilfs *nilfs = sb->s_fs_info;
329         struct nilfs_super_block **sbp;
330         int flag = NILFS_SB_COMMIT;
331         int ret = -EIO;
332
333         sbp = nilfs_prepare_super(sb, 0);
334         if (sbp) {
335                 sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
336                 nilfs_set_log_cursor(sbp[0], nilfs);
337                 if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
338                         /*
339                          * make the "clean" flag also to the opposite
340                          * super block if both super blocks point to
341                          * the same checkpoint.
342                          */
343                         sbp[1]->s_state = sbp[0]->s_state;
344                         flag = NILFS_SB_COMMIT_ALL;
345                 }
346                 ret = nilfs_commit_super(sb, flag);
347         }
348         return ret;
349 }
350
351 /**
352  * nilfs_move_2nd_super - relocate secondary super block
353  * @sb: super block instance
354  * @sb2off: new offset of the secondary super block (in bytes)
355  */
356 static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
357 {
358         struct the_nilfs *nilfs = sb->s_fs_info;
359         struct buffer_head *nsbh;
360         struct nilfs_super_block *nsbp;
361         sector_t blocknr, newblocknr;
362         unsigned long offset;
363         int sb2i = -1;  /* array index of the secondary superblock */
364         int ret = 0;
365
366         /* nilfs->ns_sem must be locked by the caller. */
367         if (nilfs->ns_sbh[1] &&
368             nilfs->ns_sbh[1]->b_blocknr > nilfs->ns_first_data_block) {
369                 sb2i = 1;
370                 blocknr = nilfs->ns_sbh[1]->b_blocknr;
371         } else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
372                 sb2i = 0;
373                 blocknr = nilfs->ns_sbh[0]->b_blocknr;
374         }
375         if (sb2i >= 0 && (u64)blocknr << nilfs->ns_blocksize_bits == sb2off)
376                 goto out;  /* super block location is unchanged */
377
378         /* Get new super block buffer */
379         newblocknr = sb2off >> nilfs->ns_blocksize_bits;
380         offset = sb2off & (nilfs->ns_blocksize - 1);
381         nsbh = sb_getblk(sb, newblocknr);
382         if (!nsbh) {
383                 printk(KERN_WARNING
384                        "NILFS warning: unable to move secondary superblock "
385                        "to block %llu\n", (unsigned long long)newblocknr);
386                 ret = -EIO;
387                 goto out;
388         }
389         nsbp = (void *)nsbh->b_data + offset;
390         memset(nsbp, 0, nilfs->ns_blocksize);
391
392         if (sb2i >= 0) {
393                 memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
394                 brelse(nilfs->ns_sbh[sb2i]);
395                 nilfs->ns_sbh[sb2i] = nsbh;
396                 nilfs->ns_sbp[sb2i] = nsbp;
397         } else if (nilfs->ns_sbh[0]->b_blocknr < nilfs->ns_first_data_block) {
398                 /* secondary super block will be restored to index 1 */
399                 nilfs->ns_sbh[1] = nsbh;
400                 nilfs->ns_sbp[1] = nsbp;
401         } else {
402                 brelse(nsbh);
403         }
404 out:
405         return ret;
406 }
407
408 /**
409  * nilfs_resize_fs - resize the filesystem
410  * @sb: super block instance
411  * @newsize: new size of the filesystem (in bytes)
412  */
413 int nilfs_resize_fs(struct super_block *sb, __u64 newsize)
414 {
415         struct the_nilfs *nilfs = sb->s_fs_info;
416         struct nilfs_super_block **sbp;
417         __u64 devsize, newnsegs;
418         loff_t sb2off;
419         int ret;
420
421         ret = -ERANGE;
422         devsize = i_size_read(sb->s_bdev->bd_inode);
423         if (newsize > devsize)
424                 goto out;
425
426         /*
427          * Write lock is required to protect some functions depending
428          * on the number of segments, the number of reserved segments,
429          * and so forth.
430          */
431         down_write(&nilfs->ns_segctor_sem);
432
433         sb2off = NILFS_SB2_OFFSET_BYTES(newsize);
434         newnsegs = sb2off >> nilfs->ns_blocksize_bits;
435         do_div(newnsegs, nilfs->ns_blocks_per_segment);
436
437         ret = nilfs_sufile_resize(nilfs->ns_sufile, newnsegs);
438         up_write(&nilfs->ns_segctor_sem);
439         if (ret < 0)
440                 goto out;
441
442         ret = nilfs_construct_segment(sb);
443         if (ret < 0)
444                 goto out;
445
446         down_write(&nilfs->ns_sem);
447         nilfs_move_2nd_super(sb, sb2off);
448         ret = -EIO;
449         sbp = nilfs_prepare_super(sb, 0);
450         if (likely(sbp)) {
451                 nilfs_set_log_cursor(sbp[0], nilfs);
452                 /*
453                  * Drop NILFS_RESIZE_FS flag for compatibility with
454                  * mount-time resize which may be implemented in a
455                  * future release.
456                  */
457                 sbp[0]->s_state = cpu_to_le16(le16_to_cpu(sbp[0]->s_state) &
458                                               ~NILFS_RESIZE_FS);
459                 sbp[0]->s_dev_size = cpu_to_le64(newsize);
460                 sbp[0]->s_nsegments = cpu_to_le64(nilfs->ns_nsegments);
461                 if (sbp[1])
462                         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
463                 ret = nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
464         }
465         up_write(&nilfs->ns_sem);
466
467         /*
468          * Reset the range of allocatable segments last.  This order
469          * is important in the case of expansion because the secondary
470          * superblock must be protected from log write until migration
471          * completes.
472          */
473         if (!ret)
474                 nilfs_sufile_set_alloc_range(nilfs->ns_sufile, 0, newnsegs - 1);
475 out:
476         return ret;
477 }
478
479 static void nilfs_put_super(struct super_block *sb)
480 {
481         struct the_nilfs *nilfs = sb->s_fs_info;
482
483         nilfs_detach_log_writer(sb);
484
485         if (!(sb->s_flags & MS_RDONLY)) {
486                 down_write(&nilfs->ns_sem);
487                 nilfs_cleanup_super(sb);
488                 up_write(&nilfs->ns_sem);
489         }
490
491         iput(nilfs->ns_sufile);
492         iput(nilfs->ns_cpfile);
493         iput(nilfs->ns_dat);
494
495         destroy_nilfs(nilfs);
496         sb->s_fs_info = NULL;
497 }
498
499 static int nilfs_sync_fs(struct super_block *sb, int wait)
500 {
501         struct the_nilfs *nilfs = sb->s_fs_info;
502         struct nilfs_super_block **sbp;
503         int err = 0;
504
505         /* This function is called when super block should be written back */
506         if (wait)
507                 err = nilfs_construct_segment(sb);
508
509         down_write(&nilfs->ns_sem);
510         if (nilfs_sb_dirty(nilfs)) {
511                 sbp = nilfs_prepare_super(sb, nilfs_sb_will_flip(nilfs));
512                 if (likely(sbp)) {
513                         nilfs_set_log_cursor(sbp[0], nilfs);
514                         nilfs_commit_super(sb, NILFS_SB_COMMIT);
515                 }
516         }
517         up_write(&nilfs->ns_sem);
518
519         return err;
520 }
521
522 int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
523                             struct nilfs_root **rootp)
524 {
525         struct the_nilfs *nilfs = sb->s_fs_info;
526         struct nilfs_root *root;
527         struct nilfs_checkpoint *raw_cp;
528         struct buffer_head *bh_cp;
529         int err = -ENOMEM;
530
531         root = nilfs_find_or_create_root(
532                 nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
533         if (!root)
534                 return err;
535
536         if (root->ifile)
537                 goto reuse; /* already attached checkpoint */
538
539         down_read(&nilfs->ns_segctor_sem);
540         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
541                                           &bh_cp);
542         up_read(&nilfs->ns_segctor_sem);
543         if (unlikely(err)) {
544                 if (err == -ENOENT || err == -EINVAL) {
545                         printk(KERN_ERR
546                                "NILFS: Invalid checkpoint "
547                                "(checkpoint number=%llu)\n",
548                                (unsigned long long)cno);
549                         err = -EINVAL;
550                 }
551                 goto failed;
552         }
553
554         err = nilfs_ifile_read(sb, root, nilfs->ns_inode_size,
555                                &raw_cp->cp_ifile_inode, &root->ifile);
556         if (err)
557                 goto failed_bh;
558
559         atomic_set(&root->inodes_count, le64_to_cpu(raw_cp->cp_inodes_count));
560         atomic_set(&root->blocks_count, le64_to_cpu(raw_cp->cp_blocks_count));
561
562         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
563
564  reuse:
565         *rootp = root;
566         return 0;
567
568  failed_bh:
569         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
570  failed:
571         nilfs_put_root(root);
572
573         return err;
574 }
575
576 static int nilfs_freeze(struct super_block *sb)
577 {
578         struct the_nilfs *nilfs = sb->s_fs_info;
579         int err;
580
581         if (sb->s_flags & MS_RDONLY)
582                 return 0;
583
584         /* Mark super block clean */
585         down_write(&nilfs->ns_sem);
586         err = nilfs_cleanup_super(sb);
587         up_write(&nilfs->ns_sem);
588         return err;
589 }
590
591 static int nilfs_unfreeze(struct super_block *sb)
592 {
593         struct the_nilfs *nilfs = sb->s_fs_info;
594
595         if (sb->s_flags & MS_RDONLY)
596                 return 0;
597
598         down_write(&nilfs->ns_sem);
599         nilfs_setup_super(sb, false);
600         up_write(&nilfs->ns_sem);
601         return 0;
602 }
603
604 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
605 {
606         struct super_block *sb = dentry->d_sb;
607         struct nilfs_root *root = NILFS_I(dentry->d_inode)->i_root;
608         struct the_nilfs *nilfs = root->nilfs;
609         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
610         unsigned long long blocks;
611         unsigned long overhead;
612         unsigned long nrsvblocks;
613         sector_t nfreeblocks;
614         int err;
615
616         /*
617          * Compute all of the segment blocks
618          *
619          * The blocks before first segment and after last segment
620          * are excluded.
621          */
622         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
623                 - nilfs->ns_first_data_block;
624         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
625
626         /*
627          * Compute the overhead
628          *
629          * When distributing meta data blocks outside segment structure,
630          * We must count them as the overhead.
631          */
632         overhead = 0;
633
634         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
635         if (unlikely(err))
636                 return err;
637
638         buf->f_type = NILFS_SUPER_MAGIC;
639         buf->f_bsize = sb->s_blocksize;
640         buf->f_blocks = blocks - overhead;
641         buf->f_bfree = nfreeblocks;
642         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
643                 (buf->f_bfree - nrsvblocks) : 0;
644         buf->f_files = atomic_read(&root->inodes_count);
645         buf->f_ffree = 0; /* nilfs_count_free_inodes(sb); */
646         buf->f_namelen = NILFS_NAME_LEN;
647         buf->f_fsid.val[0] = (u32)id;
648         buf->f_fsid.val[1] = (u32)(id >> 32);
649
650         return 0;
651 }
652
653 static int nilfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
654 {
655         struct super_block *sb = vfs->mnt_sb;
656         struct the_nilfs *nilfs = sb->s_fs_info;
657         struct nilfs_root *root = NILFS_I(vfs->mnt_root->d_inode)->i_root;
658
659         if (!nilfs_test_opt(nilfs, BARRIER))
660                 seq_puts(seq, ",nobarrier");
661         if (root->cno != NILFS_CPTREE_CURRENT_CNO)
662                 seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
663         if (nilfs_test_opt(nilfs, ERRORS_PANIC))
664                 seq_puts(seq, ",errors=panic");
665         if (nilfs_test_opt(nilfs, ERRORS_CONT))
666                 seq_puts(seq, ",errors=continue");
667         if (nilfs_test_opt(nilfs, STRICT_ORDER))
668                 seq_puts(seq, ",order=strict");
669         if (nilfs_test_opt(nilfs, NORECOVERY))
670                 seq_puts(seq, ",norecovery");
671         if (nilfs_test_opt(nilfs, DISCARD))
672                 seq_puts(seq, ",discard");
673
674         return 0;
675 }
676
677 static const struct super_operations nilfs_sops = {
678         .alloc_inode    = nilfs_alloc_inode,
679         .destroy_inode  = nilfs_destroy_inode,
680         .dirty_inode    = nilfs_dirty_inode,
681         /* .write_inode    = nilfs_write_inode, */
682         /* .put_inode      = nilfs_put_inode, */
683         /* .drop_inode    = nilfs_drop_inode, */
684         .evict_inode    = nilfs_evict_inode,
685         .put_super      = nilfs_put_super,
686         /* .write_super    = nilfs_write_super, */
687         .sync_fs        = nilfs_sync_fs,
688         .freeze_fs      = nilfs_freeze,
689         .unfreeze_fs    = nilfs_unfreeze,
690         /* .write_super_lockfs */
691         /* .unlockfs */
692         .statfs         = nilfs_statfs,
693         .remount_fs     = nilfs_remount,
694         /* .umount_begin */
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                 if (!*p)
730                         continue;
731
732                 token = match_token(p, tokens, args);
733                 switch (token) {
734                 case Opt_barrier:
735                         nilfs_set_opt(nilfs, BARRIER);
736                         break;
737                 case Opt_nobarrier:
738                         nilfs_clear_opt(nilfs, BARRIER);
739                         break;
740                 case Opt_order:
741                         if (strcmp(args[0].from, "relaxed") == 0)
742                                 /* Ordered data semantics */
743                                 nilfs_clear_opt(nilfs, STRICT_ORDER);
744                         else if (strcmp(args[0].from, "strict") == 0)
745                                 /* Strict in-order semantics */
746                                 nilfs_set_opt(nilfs, STRICT_ORDER);
747                         else
748                                 return 0;
749                         break;
750                 case Opt_err_panic:
751                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_PANIC);
752                         break;
753                 case Opt_err_ro:
754                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_RO);
755                         break;
756                 case Opt_err_cont:
757                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_CONT);
758                         break;
759                 case Opt_snapshot:
760                         if (is_remount) {
761                                 printk(KERN_ERR
762                                        "NILFS: \"%s\" option is invalid "
763                                        "for remount.\n", p);
764                                 return 0;
765                         }
766                         break;
767                 case Opt_norecovery:
768                         nilfs_set_opt(nilfs, NORECOVERY);
769                         break;
770                 case Opt_discard:
771                         nilfs_set_opt(nilfs, DISCARD);
772                         break;
773                 case Opt_nodiscard:
774                         nilfs_clear_opt(nilfs, DISCARD);
775                         break;
776                 default:
777                         printk(KERN_ERR
778                                "NILFS: Unrecognized mount option \"%s\"\n", 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                 printk(KERN_WARNING
815                        "NILFS warning: mounting fs with errors\n");
816 #if 0
817         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
818                 printk(KERN_WARNING
819                        "NILFS warning: maximal mount count reached\n");
820 #endif
821         }
822         if (!max_mnt_count)
823                 sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
824
825         sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
826         sbp[0]->s_mtime = cpu_to_le64(get_seconds());
827
828 skip_mount_setup:
829         sbp[0]->s_state =
830                 cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
831         /* synchronize sbp[1] with sbp[0] */
832         if (sbp[1])
833                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
834         return nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
835 }
836
837 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
838                                                  u64 pos, int blocksize,
839                                                  struct buffer_head **pbh)
840 {
841         unsigned long long sb_index = pos;
842         unsigned long offset;
843
844         offset = do_div(sb_index, blocksize);
845         *pbh = sb_bread(sb, sb_index);
846         if (!*pbh)
847                 return NULL;
848         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
849 }
850
851 int nilfs_store_magic_and_option(struct super_block *sb,
852                                  struct nilfs_super_block *sbp,
853                                  char *data)
854 {
855         struct the_nilfs *nilfs = sb->s_fs_info;
856
857         sb->s_magic = le16_to_cpu(sbp->s_magic);
858
859         /* FS independent flags */
860 #ifdef NILFS_ATIME_DISABLE
861         sb->s_flags |= MS_NOATIME;
862 #endif
863
864         nilfs_set_default_options(sb, sbp);
865
866         nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
867         nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
868         nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
869         nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
870
871         return !parse_options(data, sb, 0) ? -EINVAL : 0 ;
872 }
873
874 int nilfs_check_feature_compatibility(struct super_block *sb,
875                                       struct nilfs_super_block *sbp)
876 {
877         __u64 features;
878
879         features = le64_to_cpu(sbp->s_feature_incompat) &
880                 ~NILFS_FEATURE_INCOMPAT_SUPP;
881         if (features) {
882                 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
883                        "optional features (%llx)\n",
884                        (unsigned long long)features);
885                 return -EINVAL;
886         }
887         features = le64_to_cpu(sbp->s_feature_compat_ro) &
888                 ~NILFS_FEATURE_COMPAT_RO_SUPP;
889         if (!(sb->s_flags & MS_RDONLY) && features) {
890                 printk(KERN_ERR "NILFS: couldn't mount RDWR because of "
891                        "unsupported optional features (%llx)\n",
892                        (unsigned long long)features);
893                 return -EINVAL;
894         }
895         return 0;
896 }
897
898 static int nilfs_get_root_dentry(struct super_block *sb,
899                                  struct nilfs_root *root,
900                                  struct dentry **root_dentry)
901 {
902         struct inode *inode;
903         struct dentry *dentry;
904         int ret = 0;
905
906         inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
907         if (IS_ERR(inode)) {
908                 printk(KERN_ERR "NILFS: get root inode failed\n");
909                 ret = PTR_ERR(inode);
910                 goto out;
911         }
912         if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
913                 iput(inode);
914                 printk(KERN_ERR "NILFS: corrupt root inode.\n");
915                 ret = -EINVAL;
916                 goto out;
917         }
918
919         if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
920                 dentry = d_find_alias(inode);
921                 if (!dentry) {
922                         dentry = d_alloc_root(inode);
923                         if (!dentry) {
924                                 iput(inode);
925                                 ret = -ENOMEM;
926                                 goto failed_dentry;
927                         }
928                 } else {
929                         iput(inode);
930                 }
931         } else {
932                 dentry = d_obtain_alias(inode);
933                 if (IS_ERR(dentry)) {
934                         ret = PTR_ERR(dentry);
935                         goto failed_dentry;
936                 }
937         }
938         *root_dentry = dentry;
939  out:
940         return ret;
941
942  failed_dentry:
943         printk(KERN_ERR "NILFS: get root dentry failed\n");
944         goto out;
945 }
946
947 static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
948                                  struct dentry **root_dentry)
949 {
950         struct the_nilfs *nilfs = s->s_fs_info;
951         struct nilfs_root *root;
952         int ret;
953
954         down_read(&nilfs->ns_segctor_sem);
955         ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
956         up_read(&nilfs->ns_segctor_sem);
957         if (ret < 0) {
958                 ret = (ret == -ENOENT) ? -EINVAL : ret;
959                 goto out;
960         } else if (!ret) {
961                 printk(KERN_ERR "NILFS: The specified checkpoint is "
962                        "not a snapshot (checkpoint number=%llu).\n",
963                        (unsigned long long)cno);
964                 ret = -EINVAL;
965                 goto out;
966         }
967
968         ret = nilfs_attach_checkpoint(s, cno, false, &root);
969         if (ret) {
970                 printk(KERN_ERR "NILFS: error loading snapshot "
971                        "(checkpoint number=%llu).\n",
972                (unsigned long long)cno);
973                 goto out;
974         }
975         ret = nilfs_get_root_dentry(s, root, root_dentry);
976         nilfs_put_root(root);
977  out:
978         return ret;
979 }
980
981 static int nilfs_tree_was_touched(struct dentry *root_dentry)
982 {
983         return root_dentry->d_count > 1;
984 }
985
986 /**
987  * nilfs_try_to_shrink_tree() - try to shrink dentries of a checkpoint
988  * @root_dentry: root dentry of the tree to be shrunk
989  *
990  * This function returns true if the tree was in-use.
991  */
992 static int nilfs_try_to_shrink_tree(struct dentry *root_dentry)
993 {
994         if (have_submounts(root_dentry))
995                 return true;
996         shrink_dcache_parent(root_dentry);
997         return nilfs_tree_was_touched(root_dentry);
998 }
999
1000 int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
1001 {
1002         struct the_nilfs *nilfs = sb->s_fs_info;
1003         struct nilfs_root *root;
1004         struct inode *inode;
1005         struct dentry *dentry;
1006         int ret;
1007
1008         if (cno < 0 || cno > nilfs->ns_cno)
1009                 return false;
1010
1011         if (cno >= nilfs_last_cno(nilfs))
1012                 return true;    /* protect recent checkpoints */
1013
1014         ret = false;
1015         root = nilfs_lookup_root(nilfs, cno);
1016         if (root) {
1017                 inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
1018                 if (inode) {
1019                         dentry = d_find_alias(inode);
1020                         if (dentry) {
1021                                 if (nilfs_tree_was_touched(dentry))
1022                                         ret = nilfs_try_to_shrink_tree(dentry);
1023                                 dput(dentry);
1024                         }
1025                         iput(inode);
1026                 }
1027                 nilfs_put_root(root);
1028         }
1029         return ret;
1030 }
1031
1032 /**
1033  * nilfs_fill_super() - initialize a super block instance
1034  * @sb: super_block
1035  * @data: mount options
1036  * @silent: silent mode flag
1037  *
1038  * This function is called exclusively by nilfs->ns_mount_mutex.
1039  * So, the recovery process is protected from other simultaneous mounts.
1040  */
1041 static int
1042 nilfs_fill_super(struct super_block *sb, void *data, int silent)
1043 {
1044         struct the_nilfs *nilfs;
1045         struct nilfs_root *fsroot;
1046         struct backing_dev_info *bdi;
1047         __u64 cno;
1048         int err;
1049
1050         nilfs = alloc_nilfs(sb->s_bdev);
1051         if (!nilfs)
1052                 return -ENOMEM;
1053
1054         sb->s_fs_info = nilfs;
1055
1056         err = init_nilfs(nilfs, sb, (char *)data);
1057         if (err)
1058                 goto failed_nilfs;
1059
1060         sb->s_op = &nilfs_sops;
1061         sb->s_export_op = &nilfs_export_ops;
1062         sb->s_root = NULL;
1063         sb->s_time_gran = 1;
1064
1065         bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
1066         sb->s_bdi = bdi ? : &default_backing_dev_info;
1067
1068         err = load_nilfs(nilfs, sb);
1069         if (err)
1070                 goto failed_nilfs;
1071
1072         cno = nilfs_last_cno(nilfs);
1073         err = nilfs_attach_checkpoint(sb, cno, true, &fsroot);
1074         if (err) {
1075                 printk(KERN_ERR "NILFS: error loading last checkpoint "
1076                        "(checkpoint number=%llu).\n", (unsigned long long)cno);
1077                 goto failed_unload;
1078         }
1079
1080         if (!(sb->s_flags & MS_RDONLY)) {
1081                 err = nilfs_attach_log_writer(sb, fsroot);
1082                 if (err)
1083                         goto failed_checkpoint;
1084         }
1085
1086         err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
1087         if (err)
1088                 goto failed_segctor;
1089
1090         nilfs_put_root(fsroot);
1091
1092         if (!(sb->s_flags & MS_RDONLY)) {
1093                 down_write(&nilfs->ns_sem);
1094                 nilfs_setup_super(sb, true);
1095                 up_write(&nilfs->ns_sem);
1096         }
1097
1098         return 0;
1099
1100  failed_segctor:
1101         nilfs_detach_log_writer(sb);
1102
1103  failed_checkpoint:
1104         nilfs_put_root(fsroot);
1105
1106  failed_unload:
1107         iput(nilfs->ns_sufile);
1108         iput(nilfs->ns_cpfile);
1109         iput(nilfs->ns_dat);
1110
1111  failed_nilfs:
1112         destroy_nilfs(nilfs);
1113         return err;
1114 }
1115
1116 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
1117 {
1118         struct the_nilfs *nilfs = sb->s_fs_info;
1119         unsigned long old_sb_flags;
1120         unsigned long old_mount_opt;
1121         int err;
1122
1123         old_sb_flags = sb->s_flags;
1124         old_mount_opt = nilfs->ns_mount_opt;
1125
1126         if (!parse_options(data, sb, 1)) {
1127                 err = -EINVAL;
1128                 goto restore_opts;
1129         }
1130         sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
1131
1132         err = -EINVAL;
1133
1134         if (!nilfs_valid_fs(nilfs)) {
1135                 printk(KERN_WARNING "NILFS (device %s): couldn't "
1136                        "remount because the filesystem is in an "
1137                        "incomplete recovery state.\n", sb->s_id);
1138                 goto restore_opts;
1139         }
1140
1141         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1142                 goto out;
1143         if (*flags & MS_RDONLY) {
1144                 /* Shutting down log writer */
1145                 nilfs_detach_log_writer(sb);
1146                 sb->s_flags |= MS_RDONLY;
1147
1148                 /*
1149                  * Remounting a valid RW partition RDONLY, so set
1150                  * the RDONLY flag and then mark the partition as valid again.
1151                  */
1152                 down_write(&nilfs->ns_sem);
1153                 nilfs_cleanup_super(sb);
1154                 up_write(&nilfs->ns_sem);
1155         } else {
1156                 __u64 features;
1157                 struct nilfs_root *root;
1158
1159                 /*
1160                  * Mounting a RDONLY partition read-write, so reread and
1161                  * store the current valid flag.  (It may have been changed
1162                  * by fsck since we originally mounted the partition.)
1163                  */
1164                 down_read(&nilfs->ns_sem);
1165                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1166                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
1167                 up_read(&nilfs->ns_sem);
1168                 if (features) {
1169                         printk(KERN_WARNING "NILFS (device %s): couldn't "
1170                                "remount RDWR because of unsupported optional "
1171                                "features (%llx)\n",
1172                                sb->s_id, (unsigned long long)features);
1173                         err = -EROFS;
1174                         goto restore_opts;
1175                 }
1176
1177                 sb->s_flags &= ~MS_RDONLY;
1178
1179                 root = NILFS_I(sb->s_root->d_inode)->i_root;
1180                 err = nilfs_attach_log_writer(sb, root);
1181                 if (err)
1182                         goto restore_opts;
1183
1184                 down_write(&nilfs->ns_sem);
1185                 nilfs_setup_super(sb, true);
1186                 up_write(&nilfs->ns_sem);
1187         }
1188  out:
1189         return 0;
1190
1191  restore_opts:
1192         sb->s_flags = old_sb_flags;
1193         nilfs->ns_mount_opt = old_mount_opt;
1194         return err;
1195 }
1196
1197 struct nilfs_super_data {
1198         struct block_device *bdev;
1199         __u64 cno;
1200         int flags;
1201 };
1202
1203 /**
1204  * nilfs_identify - pre-read mount options needed to identify mount instance
1205  * @data: mount options
1206  * @sd: nilfs_super_data
1207  */
1208 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1209 {
1210         char *p, *options = data;
1211         substring_t args[MAX_OPT_ARGS];
1212         int token;
1213         int ret = 0;
1214
1215         do {
1216                 p = strsep(&options, ",");
1217                 if (p != NULL && *p) {
1218                         token = match_token(p, tokens, args);
1219                         if (token == Opt_snapshot) {
1220                                 if (!(sd->flags & MS_RDONLY)) {
1221                                         ret++;
1222                                 } else {
1223                                         sd->cno = simple_strtoull(args[0].from,
1224                                                                   NULL, 0);
1225                                         /*
1226                                          * No need to see the end pointer;
1227                                          * match_token() has done syntax
1228                                          * checking.
1229                                          */
1230                                         if (sd->cno == 0)
1231                                                 ret++;
1232                                 }
1233                         }
1234                         if (ret)
1235                                 printk(KERN_ERR
1236                                        "NILFS: invalid mount option: %s\n", p);
1237                 }
1238                 if (!options)
1239                         break;
1240                 BUG_ON(options == data);
1241                 *(options - 1) = ',';
1242         } while (!ret);
1243         return ret;
1244 }
1245
1246 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1247 {
1248         s->s_bdev = data;
1249         s->s_dev = s->s_bdev->bd_dev;
1250         return 0;
1251 }
1252
1253 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1254 {
1255         return (void *)s->s_bdev == data;
1256 }
1257
1258 static struct dentry *
1259 nilfs_mount(struct file_system_type *fs_type, int flags,
1260              const char *dev_name, void *data)
1261 {
1262         struct nilfs_super_data sd;
1263         struct super_block *s;
1264         fmode_t mode = FMODE_READ | FMODE_EXCL;
1265         struct dentry *root_dentry;
1266         int err, s_new = false;
1267
1268         if (!(flags & MS_RDONLY))
1269                 mode |= FMODE_WRITE;
1270
1271         sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
1272         if (IS_ERR(sd.bdev))
1273                 return ERR_CAST(sd.bdev);
1274
1275         sd.cno = 0;
1276         sd.flags = flags;
1277         if (nilfs_identify((char *)data, &sd)) {
1278                 err = -EINVAL;
1279                 goto failed;
1280         }
1281
1282         /*
1283          * once the super is inserted into the list by sget, s_umount
1284          * will protect the lockfs code from trying to start a snapshot
1285          * while we are mounting
1286          */
1287         mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
1288         if (sd.bdev->bd_fsfreeze_count > 0) {
1289                 mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1290                 err = -EBUSY;
1291                 goto failed;
1292         }
1293         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, sd.bdev);
1294         mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1295         if (IS_ERR(s)) {
1296                 err = PTR_ERR(s);
1297                 goto failed;
1298         }
1299
1300         if (!s->s_root) {
1301                 char b[BDEVNAME_SIZE];
1302
1303                 s_new = true;
1304
1305                 /* New superblock instance created */
1306                 s->s_flags = flags;
1307                 s->s_mode = mode;
1308                 strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
1309                 sb_set_blocksize(s, block_size(sd.bdev));
1310
1311                 err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
1312                 if (err)
1313                         goto failed_super;
1314
1315                 s->s_flags |= MS_ACTIVE;
1316         } else if (!sd.cno) {
1317                 int busy = false;
1318
1319                 if (nilfs_tree_was_touched(s->s_root)) {
1320                         busy = nilfs_try_to_shrink_tree(s->s_root);
1321                         if (busy && (flags ^ s->s_flags) & MS_RDONLY) {
1322                                 printk(KERN_ERR "NILFS: the device already "
1323                                        "has a %s mount.\n",
1324                                        (s->s_flags & MS_RDONLY) ?
1325                                        "read-only" : "read/write");
1326                                 err = -EBUSY;
1327                                 goto failed_super;
1328                         }
1329                 }
1330                 if (!busy) {
1331                         /*
1332                          * Try remount to setup mount states if the current
1333                          * tree is not mounted and only snapshots use this sb.
1334                          */
1335                         err = nilfs_remount(s, &flags, data);
1336                         if (err)
1337                                 goto failed_super;
1338                 }
1339         }
1340
1341         if (sd.cno) {
1342                 err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
1343                 if (err)
1344                         goto failed_super;
1345         } else {
1346                 root_dentry = dget(s->s_root);
1347         }
1348
1349         if (!s_new)
1350                 blkdev_put(sd.bdev, mode);
1351
1352         return root_dentry;
1353
1354  failed_super:
1355         deactivate_locked_super(s);
1356
1357  failed:
1358         if (!s_new)
1359                 blkdev_put(sd.bdev, mode);
1360         return ERR_PTR(err);
1361 }
1362
1363 struct file_system_type nilfs_fs_type = {
1364         .owner    = THIS_MODULE,
1365         .name     = "nilfs2",
1366         .mount    = nilfs_mount,
1367         .kill_sb  = kill_block_super,
1368         .fs_flags = FS_REQUIRES_DEV,
1369 };
1370
1371 static void nilfs_inode_init_once(void *obj)
1372 {
1373         struct nilfs_inode_info *ii = obj;
1374
1375         INIT_LIST_HEAD(&ii->i_dirty);
1376 #ifdef CONFIG_NILFS_XATTR
1377         init_rwsem(&ii->xattr_sem);
1378 #endif
1379         address_space_init_once(&ii->i_btnode_cache);
1380         ii->i_bmap = &ii->i_bmap_data;
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         if (nilfs_inode_cachep)
1392                 kmem_cache_destroy(nilfs_inode_cachep);
1393         if (nilfs_transaction_cachep)
1394                 kmem_cache_destroy(nilfs_transaction_cachep);
1395         if (nilfs_segbuf_cachep)
1396                 kmem_cache_destroy(nilfs_segbuf_cachep);
1397         if (nilfs_btree_path_cache)
1398                 kmem_cache_destroy(nilfs_btree_path_cache);
1399 }
1400
1401 static int __init nilfs_init_cachep(void)
1402 {
1403         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1404                         sizeof(struct nilfs_inode_info), 0,
1405                         SLAB_RECLAIM_ACCOUNT, nilfs_inode_init_once);
1406         if (!nilfs_inode_cachep)
1407                 goto fail;
1408
1409         nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1410                         sizeof(struct nilfs_transaction_info), 0,
1411                         SLAB_RECLAIM_ACCOUNT, NULL);
1412         if (!nilfs_transaction_cachep)
1413                 goto fail;
1414
1415         nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1416                         sizeof(struct nilfs_segment_buffer), 0,
1417                         SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1418         if (!nilfs_segbuf_cachep)
1419                 goto fail;
1420
1421         nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1422                         sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1423                         0, 0, NULL);
1424         if (!nilfs_btree_path_cache)
1425                 goto fail;
1426
1427         return 0;
1428
1429 fail:
1430         nilfs_destroy_cachep();
1431         return -ENOMEM;
1432 }
1433
1434 static int __init init_nilfs_fs(void)
1435 {
1436         int err;
1437
1438         err = nilfs_init_cachep();
1439         if (err)
1440                 goto fail;
1441
1442         err = register_filesystem(&nilfs_fs_type);
1443         if (err)
1444                 goto free_cachep;
1445
1446         printk(KERN_INFO "NILFS version 2 loaded\n");
1447         return 0;
1448
1449 free_cachep:
1450         nilfs_destroy_cachep();
1451 fail:
1452         return err;
1453 }
1454
1455 static void __exit exit_nilfs_fs(void)
1456 {
1457         nilfs_destroy_cachep();
1458         unregister_filesystem(&nilfs_fs_type);
1459 }
1460
1461 module_init(init_nilfs_fs)
1462 module_exit(exit_nilfs_fs)