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Linux/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  * Written by Ryusuke Konishi.
 17  */
 18 /*
 19  *  linux/fs/ext2/super.c
 20  *
 21  * Copyright (C) 1992, 1993, 1994, 1995
 22  * Remy Card (card@masi.ibp.fr)
 23  * Laboratoire MASI - Institut Blaise Pascal
 24  * Universite Pierre et Marie Curie (Paris VI)
 25  *
 26  *  from
 27  *
 28  *  linux/fs/minix/inode.c
 29  *
 30  *  Copyright (C) 1991, 1992  Linus Torvalds
 31  *
 32  *  Big-endian to little-endian byte-swapping/bitmaps by
 33  *        David S. Miller (davem@caip.rutgers.edu), 1995
 34  */
 35 
 36 #include <linux/module.h>
 37 #include <linux/string.h>
 38 #include <linux/slab.h>
 39 #include <linux/init.h>
 40 #include <linux/blkdev.h>
 41 #include <linux/parser.h>
 42 #include <linux/crc32.h>
 43 #include <linux/vfs.h>
 44 #include <linux/writeback.h>
 45 #include <linux/seq_file.h>
 46 #include <linux/mount.h>
 47 #include "nilfs.h"
 48 #include "export.h"
 49 #include "mdt.h"
 50 #include "alloc.h"
 51 #include "btree.h"
 52 #include "btnode.h"
 53 #include "page.h"
 54 #include "cpfile.h"
 55 #include "sufile.h" /* nilfs_sufile_resize(), nilfs_sufile_set_alloc_range() */
 56 #include "ifile.h"
 57 #include "dat.h"
 58 #include "segment.h"
 59 #include "segbuf.h"
 60 
 61 MODULE_AUTHOR("NTT Corp.");
 62 MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
 63                    "(NILFS)");
 64 MODULE_LICENSE("GPL");
 65 
 66 static struct kmem_cache *nilfs_inode_cachep;
 67 struct kmem_cache *nilfs_transaction_cachep;
 68 struct kmem_cache *nilfs_segbuf_cachep;
 69 struct kmem_cache *nilfs_btree_path_cache;
 70 
 71 static int nilfs_setup_super(struct super_block *sb, int is_mount);
 72 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
 73 
 74 static void nilfs_set_error(struct super_block *sb)
 75 {
 76         struct the_nilfs *nilfs = sb->s_fs_info;
 77         struct nilfs_super_block **sbp;
 78 
 79         down_write(&nilfs->ns_sem);
 80         if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
 81                 nilfs->ns_mount_state |= NILFS_ERROR_FS;
 82                 sbp = nilfs_prepare_super(sb, 0);
 83                 if (likely(sbp)) {
 84                         sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
 85                         if (sbp[1])
 86                                 sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
 87                         nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 88                 }
 89         }
 90         up_write(&nilfs->ns_sem);
 91 }
 92 
 93 /**
 94  * nilfs_error() - report failure condition on a filesystem
 95  *
 96  * nilfs_error() sets an ERROR_FS flag on the superblock as well as
 97  * reporting an error message.  It should be called when NILFS detects
 98  * incoherences or defects of meta data on disk.  As for sustainable
 99  * errors such as a single-shot I/O error, nilfs_warning() or the printk()
100  * function should be used instead.
101  *
102  * The segment constructor must not call this function because it can
103  * kill itself.
104  */
105 void nilfs_error(struct super_block *sb, const char *function,
106                  const char *fmt, ...)
107 {
108         struct the_nilfs *nilfs = sb->s_fs_info;
109         struct va_format vaf;
110         va_list args;
111 
112         va_start(args, fmt);
113 
114         vaf.fmt = fmt;
115         vaf.va = &args;
116 
117         printk(KERN_CRIT "NILFS error (device %s): %s: %pV\n",
118                sb->s_id, function, &vaf);
119 
120         va_end(args);
121 
122         if (!(sb->s_flags & MS_RDONLY)) {
123                 nilfs_set_error(sb);
124 
125                 if (nilfs_test_opt(nilfs, ERRORS_RO)) {
126                         printk(KERN_CRIT "Remounting filesystem read-only\n");
127                         sb->s_flags |= MS_RDONLY;
128                 }
129         }
130 
131         if (nilfs_test_opt(nilfs, ERRORS_PANIC))
132                 panic("NILFS (device %s): panic forced after error\n",
133                       sb->s_id);
134 }
135 
136 void nilfs_warning(struct super_block *sb, const char *function,
137                    const char *fmt, ...)
138 {
139         struct va_format vaf;
140         va_list args;
141 
142         va_start(args, fmt);
143 
144         vaf.fmt = fmt;
145         vaf.va = &args;
146 
147         printk(KERN_WARNING "NILFS warning (device %s): %s: %pV\n",
148                sb->s_id, function, &vaf);
149 
150         va_end(args);
151 }
152 
153 
154 struct inode *nilfs_alloc_inode(struct super_block *sb)
155 {
156         struct nilfs_inode_info *ii;
157 
158         ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
159         if (!ii)
160                 return NULL;
161         ii->i_bh = NULL;
162         ii->i_state = 0;
163         ii->i_cno = 0;
164         ii->vfs_inode.i_version = 1;
165         nilfs_mapping_init(&ii->i_btnode_cache, &ii->vfs_inode);
166         return &ii->vfs_inode;
167 }
168 
169 static void nilfs_i_callback(struct rcu_head *head)
170 {
171         struct inode *inode = container_of(head, struct inode, i_rcu);
172 
173         if (nilfs_is_metadata_file_inode(inode))
174                 nilfs_mdt_destroy(inode);
175 
176         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
177 }
178 
179 void nilfs_destroy_inode(struct inode *inode)
180 {
181         call_rcu(&inode->i_rcu, nilfs_i_callback);
182 }
183 
184 static int nilfs_sync_super(struct super_block *sb, int flag)
185 {
186         struct the_nilfs *nilfs = sb->s_fs_info;
187         int err;
188 
189  retry:
190         set_buffer_dirty(nilfs->ns_sbh[0]);
191         if (nilfs_test_opt(nilfs, BARRIER)) {
192                 err = __sync_dirty_buffer(nilfs->ns_sbh[0],
193                                           WRITE_SYNC | WRITE_FLUSH_FUA);
194         } else {
195                 err = sync_dirty_buffer(nilfs->ns_sbh[0]);
196         }
197 
198         if (unlikely(err)) {
199                 printk(KERN_ERR
200                        "NILFS: unable to write superblock (err=%d)\n", err);
201                 if (err == -EIO && nilfs->ns_sbh[1]) {
202                         /*
203                          * sbp[0] points to newer log than sbp[1],
204                          * so copy sbp[0] to sbp[1] to take over sbp[0].
205                          */
206                         memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
207                                nilfs->ns_sbsize);
208                         nilfs_fall_back_super_block(nilfs);
209                         goto retry;
210                 }
211         } else {
212                 struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
213 
214                 nilfs->ns_sbwcount++;
215 
216                 /*
217                  * The latest segment becomes trailable from the position
218                  * written in superblock.
219                  */
220                 clear_nilfs_discontinued(nilfs);
221 
222                 /* update GC protection for recent segments */
223                 if (nilfs->ns_sbh[1]) {
224                         if (flag == NILFS_SB_COMMIT_ALL) {
225                                 set_buffer_dirty(nilfs->ns_sbh[1]);
226                                 if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
227                                         goto out;
228                         }
229                         if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
230                             le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
231                                 sbp = nilfs->ns_sbp[1];
232                 }
233 
234                 spin_lock(&nilfs->ns_last_segment_lock);
235                 nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
236                 spin_unlock(&nilfs->ns_last_segment_lock);
237         }
238  out:
239         return err;
240 }
241 
242 void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
243                           struct the_nilfs *nilfs)
244 {
245         sector_t nfreeblocks;
246 
247         /* nilfs->ns_sem must be locked by the caller. */
248         nilfs_count_free_blocks(nilfs, &nfreeblocks);
249         sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
250 
251         spin_lock(&nilfs->ns_last_segment_lock);
252         sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
253         sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
254         sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
255         spin_unlock(&nilfs->ns_last_segment_lock);
256 }
257 
258 struct nilfs_super_block **nilfs_prepare_super(struct super_block *sb,
259                                                int flip)
260 {
261         struct the_nilfs *nilfs = sb->s_fs_info;
262         struct nilfs_super_block **sbp = nilfs->ns_sbp;
263 
264         /* nilfs->ns_sem must be locked by the caller. */
265         if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
266                 if (sbp[1] &&
267                     sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
268                         memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
269                 } else {
270                         printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
271                                sb->s_id);
272                         return NULL;
273                 }
274         } else if (sbp[1] &&
275                    sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
276                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
277         }
278 
279         if (flip && sbp[1])
280                 nilfs_swap_super_block(nilfs);
281 
282         return sbp;
283 }
284 
285 int nilfs_commit_super(struct super_block *sb, int flag)
286 {
287         struct the_nilfs *nilfs = sb->s_fs_info;
288         struct nilfs_super_block **sbp = nilfs->ns_sbp;
289         time_t t;
290 
291         /* nilfs->ns_sem must be locked by the caller. */
292         t = get_seconds();
293         nilfs->ns_sbwtime = t;
294         sbp[0]->s_wtime = cpu_to_le64(t);
295         sbp[0]->s_sum = 0;
296         sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
297                                              (unsigned char *)sbp[0],
298                                              nilfs->ns_sbsize));
299         if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
300                 sbp[1]->s_wtime = sbp[0]->s_wtime;
301                 sbp[1]->s_sum = 0;
302                 sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
303                                             (unsigned char *)sbp[1],
304                                             nilfs->ns_sbsize));
305         }
306         clear_nilfs_sb_dirty(nilfs);
307         nilfs->ns_flushed_device = 1;
308         /* make sure store to ns_flushed_device cannot be reordered */
309         smp_wmb();
310         return nilfs_sync_super(sb, flag);
311 }
312 
313 /**
314  * nilfs_cleanup_super() - write filesystem state for cleanup
315  * @sb: super block instance to be unmounted or degraded to read-only
316  *
317  * This function restores state flags in the on-disk super block.
318  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
319  * filesystem was not clean previously.
320  */
321 int nilfs_cleanup_super(struct super_block *sb)
322 {
323         struct the_nilfs *nilfs = sb->s_fs_info;
324         struct nilfs_super_block **sbp;
325         int flag = NILFS_SB_COMMIT;
326         int ret = -EIO;
327 
328         sbp = nilfs_prepare_super(sb, 0);
329         if (sbp) {
330                 sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
331                 nilfs_set_log_cursor(sbp[0], nilfs);
332                 if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
333                         /*
334                          * make the "clean" flag also to the opposite
335                          * super block if both super blocks point to
336                          * the same checkpoint.
337                          */
338                         sbp[1]->s_state = sbp[0]->s_state;
339                         flag = NILFS_SB_COMMIT_ALL;
340                 }
341                 ret = nilfs_commit_super(sb, flag);
342         }
343         return ret;
344 }
345 
346 /**
347  * nilfs_move_2nd_super - relocate secondary super block
348  * @sb: super block instance
349  * @sb2off: new offset of the secondary super block (in bytes)
350  */
351 static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
352 {
353         struct the_nilfs *nilfs = sb->s_fs_info;
354         struct buffer_head *nsbh;
355         struct nilfs_super_block *nsbp;
356         sector_t blocknr, newblocknr;
357         unsigned long offset;
358         int sb2i;  /* array index of the secondary superblock */
359         int ret = 0;
360 
361         /* nilfs->ns_sem must be locked by the caller. */
362         if (nilfs->ns_sbh[1] &&
363             nilfs->ns_sbh[1]->b_blocknr > nilfs->ns_first_data_block) {
364                 sb2i = 1;
365                 blocknr = nilfs->ns_sbh[1]->b_blocknr;
366         } else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
367                 sb2i = 0;
368                 blocknr = nilfs->ns_sbh[0]->b_blocknr;
369         } else {
370                 sb2i = -1;
371                 blocknr = 0;
372         }
373         if (sb2i >= 0 && (u64)blocknr << nilfs->ns_blocksize_bits == sb2off)
374                 goto out;  /* super block location is unchanged */
375 
376         /* Get new super block buffer */
377         newblocknr = sb2off >> nilfs->ns_blocksize_bits;
378         offset = sb2off & (nilfs->ns_blocksize - 1);
379         nsbh = sb_getblk(sb, newblocknr);
380         if (!nsbh) {
381                 printk(KERN_WARNING
382                        "NILFS warning: unable to move secondary superblock "
383                        "to block %llu\n", (unsigned long long)newblocknr);
384                 ret = -EIO;
385                 goto out;
386         }
387         nsbp = (void *)nsbh->b_data + offset;
388         memset(nsbp, 0, nilfs->ns_blocksize);
389 
390         if (sb2i >= 0) {
391                 memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
392                 brelse(nilfs->ns_sbh[sb2i]);
393                 nilfs->ns_sbh[sb2i] = nsbh;
394                 nilfs->ns_sbp[sb2i] = nsbp;
395         } else if (nilfs->ns_sbh[0]->b_blocknr < nilfs->ns_first_data_block) {
396                 /* secondary super block will be restored to index 1 */
397                 nilfs->ns_sbh[1] = nsbh;
398                 nilfs->ns_sbp[1] = nsbp;
399         } else {
400                 brelse(nsbh);
401         }
402 out:
403         return ret;
404 }
405 
406 /**
407  * nilfs_resize_fs - resize the filesystem
408  * @sb: super block instance
409  * @newsize: new size of the filesystem (in bytes)
410  */
411 int nilfs_resize_fs(struct super_block *sb, __u64 newsize)
412 {
413         struct the_nilfs *nilfs = sb->s_fs_info;
414         struct nilfs_super_block **sbp;
415         __u64 devsize, newnsegs;
416         loff_t sb2off;
417         int ret;
418 
419         ret = -ERANGE;
420         devsize = i_size_read(sb->s_bdev->bd_inode);
421         if (newsize > devsize)
422                 goto out;
423 
424         /*
425          * Write lock is required to protect some functions depending
426          * on the number of segments, the number of reserved segments,
427          * and so forth.
428          */
429         down_write(&nilfs->ns_segctor_sem);
430 
431         sb2off = NILFS_SB2_OFFSET_BYTES(newsize);
432         newnsegs = sb2off >> nilfs->ns_blocksize_bits;
433         do_div(newnsegs, nilfs->ns_blocks_per_segment);
434 
435         ret = nilfs_sufile_resize(nilfs->ns_sufile, newnsegs);
436         up_write(&nilfs->ns_segctor_sem);
437         if (ret < 0)
438                 goto out;
439 
440         ret = nilfs_construct_segment(sb);
441         if (ret < 0)
442                 goto out;
443 
444         down_write(&nilfs->ns_sem);
445         nilfs_move_2nd_super(sb, sb2off);
446         ret = -EIO;
447         sbp = nilfs_prepare_super(sb, 0);
448         if (likely(sbp)) {
449                 nilfs_set_log_cursor(sbp[0], nilfs);
450                 /*
451                  * Drop NILFS_RESIZE_FS flag for compatibility with
452                  * mount-time resize which may be implemented in a
453                  * future release.
454                  */
455                 sbp[0]->s_state = cpu_to_le16(le16_to_cpu(sbp[0]->s_state) &
456                                               ~NILFS_RESIZE_FS);
457                 sbp[0]->s_dev_size = cpu_to_le64(newsize);
458                 sbp[0]->s_nsegments = cpu_to_le64(nilfs->ns_nsegments);
459                 if (sbp[1])
460                         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
461                 ret = nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
462         }
463         up_write(&nilfs->ns_sem);
464 
465         /*
466          * Reset the range of allocatable segments last.  This order
467          * is important in the case of expansion because the secondary
468          * superblock must be protected from log write until migration
469          * completes.
470          */
471         if (!ret)
472                 nilfs_sufile_set_alloc_range(nilfs->ns_sufile, 0, newnsegs - 1);
473 out:
474         return ret;
475 }
476 
477 static void nilfs_put_super(struct super_block *sb)
478 {
479         struct the_nilfs *nilfs = sb->s_fs_info;
480 
481         nilfs_detach_log_writer(sb);
482 
483         if (!(sb->s_flags & MS_RDONLY)) {
484                 down_write(&nilfs->ns_sem);
485                 nilfs_cleanup_super(sb);
486                 up_write(&nilfs->ns_sem);
487         }
488 
489         iput(nilfs->ns_sufile);
490         iput(nilfs->ns_cpfile);
491         iput(nilfs->ns_dat);
492 
493         destroy_nilfs(nilfs);
494         sb->s_fs_info = NULL;
495 }
496 
497 static int nilfs_sync_fs(struct super_block *sb, int wait)
498 {
499         struct the_nilfs *nilfs = sb->s_fs_info;
500         struct nilfs_super_block **sbp;
501         int err = 0;
502 
503         /* This function is called when super block should be written back */
504         if (wait)
505                 err = nilfs_construct_segment(sb);
506 
507         down_write(&nilfs->ns_sem);
508         if (nilfs_sb_dirty(nilfs)) {
509                 sbp = nilfs_prepare_super(sb, nilfs_sb_will_flip(nilfs));
510                 if (likely(sbp)) {
511                         nilfs_set_log_cursor(sbp[0], nilfs);
512                         nilfs_commit_super(sb, NILFS_SB_COMMIT);
513                 }
514         }
515         up_write(&nilfs->ns_sem);
516 
517         if (!err)
518                 err = nilfs_flush_device(nilfs);
519 
520         return err;
521 }
522 
523 int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
524                             struct nilfs_root **rootp)
525 {
526         struct the_nilfs *nilfs = sb->s_fs_info;
527         struct nilfs_root *root;
528         struct nilfs_checkpoint *raw_cp;
529         struct buffer_head *bh_cp;
530         int err = -ENOMEM;
531 
532         root = nilfs_find_or_create_root(
533                 nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
534         if (!root)
535                 return err;
536 
537         if (root->ifile)
538                 goto reuse; /* already attached checkpoint */
539 
540         down_read(&nilfs->ns_segctor_sem);
541         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
542                                           &bh_cp);
543         up_read(&nilfs->ns_segctor_sem);
544         if (unlikely(err)) {
545                 if (err == -ENOENT || err == -EINVAL) {
546                         printk(KERN_ERR
547                                "NILFS: Invalid checkpoint "
548                                "(checkpoint number=%llu)\n",
549                                (unsigned long long)cno);
550                         err = -EINVAL;
551                 }
552                 goto failed;
553         }
554 
555         err = nilfs_ifile_read(sb, root, nilfs->ns_inode_size,
556                                &raw_cp->cp_ifile_inode, &root->ifile);
557         if (err)
558                 goto failed_bh;
559 
560         atomic64_set(&root->inodes_count,
561                         le64_to_cpu(raw_cp->cp_inodes_count));
562         atomic64_set(&root->blocks_count,
563                         le64_to_cpu(raw_cp->cp_blocks_count));
564 
565         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
566 
567  reuse:
568         *rootp = root;
569         return 0;
570 
571  failed_bh:
572         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
573  failed:
574         nilfs_put_root(root);
575 
576         return err;
577 }
578 
579 static int nilfs_freeze(struct super_block *sb)
580 {
581         struct the_nilfs *nilfs = sb->s_fs_info;
582         int err;
583 
584         if (sb->s_flags & MS_RDONLY)
585                 return 0;
586 
587         /* Mark super block clean */
588         down_write(&nilfs->ns_sem);
589         err = nilfs_cleanup_super(sb);
590         up_write(&nilfs->ns_sem);
591         return err;
592 }
593 
594 static int nilfs_unfreeze(struct super_block *sb)
595 {
596         struct the_nilfs *nilfs = sb->s_fs_info;
597 
598         if (sb->s_flags & MS_RDONLY)
599                 return 0;
600 
601         down_write(&nilfs->ns_sem);
602         nilfs_setup_super(sb, false);
603         up_write(&nilfs->ns_sem);
604         return 0;
605 }
606 
607 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
608 {
609         struct super_block *sb = dentry->d_sb;
610         struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
611         struct the_nilfs *nilfs = root->nilfs;
612         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
613         unsigned long long blocks;
614         unsigned long overhead;
615         unsigned long nrsvblocks;
616         sector_t nfreeblocks;
617         u64 nmaxinodes, nfreeinodes;
618         int err;
619 
620         /*
621          * Compute all of the segment blocks
622          *
623          * The blocks before first segment and after last segment
624          * are excluded.
625          */
626         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
627                 - nilfs->ns_first_data_block;
628         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
629 
630         /*
631          * Compute the overhead
632          *
633          * When distributing meta data blocks outside segment structure,
634          * We must count them as the overhead.
635          */
636         overhead = 0;
637 
638         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
639         if (unlikely(err))
640                 return err;
641 
642         err = nilfs_ifile_count_free_inodes(root->ifile,
643                                             &nmaxinodes, &nfreeinodes);
644         if (unlikely(err)) {
645                 printk(KERN_WARNING
646                         "NILFS warning: fail to count free inodes: err %d.\n",
647                         err);
648                 if (err == -ERANGE) {
649                         /*
650                          * If nilfs_palloc_count_max_entries() returns
651                          * -ERANGE error code then we simply treat
652                          * curent inodes count as maximum possible and
653                          * zero as free inodes value.
654                          */
655                         nmaxinodes = atomic64_read(&root->inodes_count);
656                         nfreeinodes = 0;
657                         err = 0;
658                 } else
659                         return err;
660         }
661 
662         buf->f_type = NILFS_SUPER_MAGIC;
663         buf->f_bsize = sb->s_blocksize;
664         buf->f_blocks = blocks - overhead;
665         buf->f_bfree = nfreeblocks;
666         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
667                 (buf->f_bfree - nrsvblocks) : 0;
668         buf->f_files = nmaxinodes;
669         buf->f_ffree = nfreeinodes;
670         buf->f_namelen = NILFS_NAME_LEN;
671         buf->f_fsid.val[0] = (u32)id;
672         buf->f_fsid.val[1] = (u32)(id >> 32);
673 
674         return 0;
675 }
676 
677 static int nilfs_show_options(struct seq_file *seq, struct dentry *dentry)
678 {
679         struct super_block *sb = dentry->d_sb;
680         struct the_nilfs *nilfs = sb->s_fs_info;
681         struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
682 
683         if (!nilfs_test_opt(nilfs, BARRIER))
684                 seq_puts(seq, ",nobarrier");
685         if (root->cno != NILFS_CPTREE_CURRENT_CNO)
686                 seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
687         if (nilfs_test_opt(nilfs, ERRORS_PANIC))
688                 seq_puts(seq, ",errors=panic");
689         if (nilfs_test_opt(nilfs, ERRORS_CONT))
690                 seq_puts(seq, ",errors=continue");
691         if (nilfs_test_opt(nilfs, STRICT_ORDER))
692                 seq_puts(seq, ",order=strict");
693         if (nilfs_test_opt(nilfs, NORECOVERY))
694                 seq_puts(seq, ",norecovery");
695         if (nilfs_test_opt(nilfs, DISCARD))
696                 seq_puts(seq, ",discard");
697 
698         return 0;
699 }
700 
701 static const struct super_operations nilfs_sops = {
702         .alloc_inode    = nilfs_alloc_inode,
703         .destroy_inode  = nilfs_destroy_inode,
704         .dirty_inode    = nilfs_dirty_inode,
705         .evict_inode    = nilfs_evict_inode,
706         .put_super      = nilfs_put_super,
707         .sync_fs        = nilfs_sync_fs,
708         .freeze_fs      = nilfs_freeze,
709         .unfreeze_fs    = nilfs_unfreeze,
710         .statfs         = nilfs_statfs,
711         .remount_fs     = nilfs_remount,
712         .show_options = nilfs_show_options
713 };
714 
715 enum {
716         Opt_err_cont, Opt_err_panic, Opt_err_ro,
717         Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
718         Opt_discard, Opt_nodiscard, Opt_err,
719 };
720 
721 static match_table_t tokens = {
722         {Opt_err_cont, "errors=continue"},
723         {Opt_err_panic, "errors=panic"},
724         {Opt_err_ro, "errors=remount-ro"},
725         {Opt_barrier, "barrier"},
726         {Opt_nobarrier, "nobarrier"},
727         {Opt_snapshot, "cp=%u"},
728         {Opt_order, "order=%s"},
729         {Opt_norecovery, "norecovery"},
730         {Opt_discard, "discard"},
731         {Opt_nodiscard, "nodiscard"},
732         {Opt_err, NULL}
733 };
734 
735 static int parse_options(char *options, struct super_block *sb, int is_remount)
736 {
737         struct the_nilfs *nilfs = sb->s_fs_info;
738         char *p;
739         substring_t args[MAX_OPT_ARGS];
740 
741         if (!options)
742                 return 1;
743 
744         while ((p = strsep(&options, ",")) != NULL) {
745                 int token;
746 
747                 if (!*p)
748                         continue;
749 
750                 token = match_token(p, tokens, args);
751                 switch (token) {
752                 case Opt_barrier:
753                         nilfs_set_opt(nilfs, BARRIER);
754                         break;
755                 case Opt_nobarrier:
756                         nilfs_clear_opt(nilfs, BARRIER);
757                         break;
758                 case Opt_order:
759                         if (strcmp(args[0].from, "relaxed") == 0)
760                                 /* Ordered data semantics */
761                                 nilfs_clear_opt(nilfs, STRICT_ORDER);
762                         else if (strcmp(args[0].from, "strict") == 0)
763                                 /* Strict in-order semantics */
764                                 nilfs_set_opt(nilfs, STRICT_ORDER);
765                         else
766                                 return 0;
767                         break;
768                 case Opt_err_panic:
769                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_PANIC);
770                         break;
771                 case Opt_err_ro:
772                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_RO);
773                         break;
774                 case Opt_err_cont:
775                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_CONT);
776                         break;
777                 case Opt_snapshot:
778                         if (is_remount) {
779                                 printk(KERN_ERR
780                                        "NILFS: \"%s\" option is invalid "
781                                        "for remount.\n", p);
782                                 return 0;
783                         }
784                         break;
785                 case Opt_norecovery:
786                         nilfs_set_opt(nilfs, NORECOVERY);
787                         break;
788                 case Opt_discard:
789                         nilfs_set_opt(nilfs, DISCARD);
790                         break;
791                 case Opt_nodiscard:
792                         nilfs_clear_opt(nilfs, DISCARD);
793                         break;
794                 default:
795                         printk(KERN_ERR
796                                "NILFS: Unrecognized mount option \"%s\"\n", p);
797                         return 0;
798                 }
799         }
800         return 1;
801 }
802 
803 static inline void
804 nilfs_set_default_options(struct super_block *sb,
805                           struct nilfs_super_block *sbp)
806 {
807         struct the_nilfs *nilfs = sb->s_fs_info;
808 
809         nilfs->ns_mount_opt =
810                 NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
811 }
812 
813 static int nilfs_setup_super(struct super_block *sb, int is_mount)
814 {
815         struct the_nilfs *nilfs = sb->s_fs_info;
816         struct nilfs_super_block **sbp;
817         int max_mnt_count;
818         int mnt_count;
819 
820         /* nilfs->ns_sem must be locked by the caller. */
821         sbp = nilfs_prepare_super(sb, 0);
822         if (!sbp)
823                 return -EIO;
824 
825         if (!is_mount)
826                 goto skip_mount_setup;
827 
828         max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
829         mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
830 
831         if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
832                 printk(KERN_WARNING
833                        "NILFS warning: mounting fs with errors\n");
834 #if 0
835         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
836                 printk(KERN_WARNING
837                        "NILFS warning: maximal mount count reached\n");
838 #endif
839         }
840         if (!max_mnt_count)
841                 sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
842 
843         sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
844         sbp[0]->s_mtime = cpu_to_le64(get_seconds());
845 
846 skip_mount_setup:
847         sbp[0]->s_state =
848                 cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
849         /* synchronize sbp[1] with sbp[0] */
850         if (sbp[1])
851                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
852         return nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
853 }
854 
855 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
856                                                  u64 pos, int blocksize,
857                                                  struct buffer_head **pbh)
858 {
859         unsigned long long sb_index = pos;
860         unsigned long offset;
861 
862         offset = do_div(sb_index, blocksize);
863         *pbh = sb_bread(sb, sb_index);
864         if (!*pbh)
865                 return NULL;
866         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
867 }
868 
869 int nilfs_store_magic_and_option(struct super_block *sb,
870                                  struct nilfs_super_block *sbp,
871                                  char *data)
872 {
873         struct the_nilfs *nilfs = sb->s_fs_info;
874 
875         sb->s_magic = le16_to_cpu(sbp->s_magic);
876 
877         /* FS independent flags */
878 #ifdef NILFS_ATIME_DISABLE
879         sb->s_flags |= MS_NOATIME;
880 #endif
881 
882         nilfs_set_default_options(sb, sbp);
883 
884         nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
885         nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
886         nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
887         nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
888 
889         return !parse_options(data, sb, 0) ? -EINVAL : 0;
890 }
891 
892 int nilfs_check_feature_compatibility(struct super_block *sb,
893                                       struct nilfs_super_block *sbp)
894 {
895         __u64 features;
896 
897         features = le64_to_cpu(sbp->s_feature_incompat) &
898                 ~NILFS_FEATURE_INCOMPAT_SUPP;
899         if (features) {
900                 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
901                        "optional features (%llx)\n",
902                        (unsigned long long)features);
903                 return -EINVAL;
904         }
905         features = le64_to_cpu(sbp->s_feature_compat_ro) &
906                 ~NILFS_FEATURE_COMPAT_RO_SUPP;
907         if (!(sb->s_flags & MS_RDONLY) && features) {
908                 printk(KERN_ERR "NILFS: couldn't mount RDWR because of "
909                        "unsupported optional features (%llx)\n",
910                        (unsigned long long)features);
911                 return -EINVAL;
912         }
913         return 0;
914 }
915 
916 static int nilfs_get_root_dentry(struct super_block *sb,
917                                  struct nilfs_root *root,
918                                  struct dentry **root_dentry)
919 {
920         struct inode *inode;
921         struct dentry *dentry;
922         int ret = 0;
923 
924         inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
925         if (IS_ERR(inode)) {
926                 printk(KERN_ERR "NILFS: get root inode failed\n");
927                 ret = PTR_ERR(inode);
928                 goto out;
929         }
930         if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
931                 iput(inode);
932                 printk(KERN_ERR "NILFS: corrupt root inode.\n");
933                 ret = -EINVAL;
934                 goto out;
935         }
936 
937         if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
938                 dentry = d_find_alias(inode);
939                 if (!dentry) {
940                         dentry = d_make_root(inode);
941                         if (!dentry) {
942                                 ret = -ENOMEM;
943                                 goto failed_dentry;
944                         }
945                 } else {
946                         iput(inode);
947                 }
948         } else {
949                 dentry = d_obtain_root(inode);
950                 if (IS_ERR(dentry)) {
951                         ret = PTR_ERR(dentry);
952                         goto failed_dentry;
953                 }
954         }
955         *root_dentry = dentry;
956  out:
957         return ret;
958 
959  failed_dentry:
960         printk(KERN_ERR "NILFS: get root dentry failed\n");
961         goto out;
962 }
963 
964 static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
965                                  struct dentry **root_dentry)
966 {
967         struct the_nilfs *nilfs = s->s_fs_info;
968         struct nilfs_root *root;
969         int ret;
970 
971         mutex_lock(&nilfs->ns_snapshot_mount_mutex);
972 
973         down_read(&nilfs->ns_segctor_sem);
974         ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
975         up_read(&nilfs->ns_segctor_sem);
976         if (ret < 0) {
977                 ret = (ret == -ENOENT) ? -EINVAL : ret;
978                 goto out;
979         } else if (!ret) {
980                 printk(KERN_ERR "NILFS: The specified checkpoint is "
981                        "not a snapshot (checkpoint number=%llu).\n",
982                        (unsigned long long)cno);
983                 ret = -EINVAL;
984                 goto out;
985         }
986 
987         ret = nilfs_attach_checkpoint(s, cno, false, &root);
988         if (ret) {
989                 printk(KERN_ERR "NILFS: error loading snapshot "
990                        "(checkpoint number=%llu).\n",
991                (unsigned long long)cno);
992                 goto out;
993         }
994         ret = nilfs_get_root_dentry(s, root, root_dentry);
995         nilfs_put_root(root);
996  out:
997         mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
998         return ret;
999 }
1000 
1001 /**
1002  * nilfs_tree_is_busy() - try to shrink dentries of a checkpoint
1003  * @root_dentry: root dentry of the tree to be shrunk
1004  *
1005  * This function returns true if the tree was in-use.
1006  */
1007 static bool nilfs_tree_is_busy(struct dentry *root_dentry)
1008 {
1009         shrink_dcache_parent(root_dentry);
1010         return d_count(root_dentry) > 1;
1011 }
1012 
1013 int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
1014 {
1015         struct the_nilfs *nilfs = sb->s_fs_info;
1016         struct nilfs_root *root;
1017         struct inode *inode;
1018         struct dentry *dentry;
1019         int ret;
1020 
1021         if (cno > nilfs->ns_cno)
1022                 return false;
1023 
1024         if (cno >= nilfs_last_cno(nilfs))
1025                 return true;    /* protect recent checkpoints */
1026 
1027         ret = false;
1028         root = nilfs_lookup_root(nilfs, cno);
1029         if (root) {
1030                 inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
1031                 if (inode) {
1032                         dentry = d_find_alias(inode);
1033                         if (dentry) {
1034                                 ret = nilfs_tree_is_busy(dentry);
1035                                 dput(dentry);
1036                         }
1037                         iput(inode);
1038                 }
1039                 nilfs_put_root(root);
1040         }
1041         return ret;
1042 }
1043 
1044 /**
1045  * nilfs_fill_super() - initialize a super block instance
1046  * @sb: super_block
1047  * @data: mount options
1048  * @silent: silent mode flag
1049  *
1050  * This function is called exclusively by nilfs->ns_mount_mutex.
1051  * So, the recovery process is protected from other simultaneous mounts.
1052  */
1053 static int
1054 nilfs_fill_super(struct super_block *sb, void *data, int silent)
1055 {
1056         struct the_nilfs *nilfs;
1057         struct nilfs_root *fsroot;
1058         __u64 cno;
1059         int err;
1060 
1061         nilfs = alloc_nilfs(sb->s_bdev);
1062         if (!nilfs)
1063                 return -ENOMEM;
1064 
1065         sb->s_fs_info = nilfs;
1066 
1067         err = init_nilfs(nilfs, sb, (char *)data);
1068         if (err)
1069                 goto failed_nilfs;
1070 
1071         sb->s_op = &nilfs_sops;
1072         sb->s_export_op = &nilfs_export_ops;
1073         sb->s_root = NULL;
1074         sb->s_time_gran = 1;
1075         sb->s_max_links = NILFS_LINK_MAX;
1076 
1077         sb->s_bdi = &bdev_get_queue(sb->s_bdev)->backing_dev_info;
1078 
1079         err = load_nilfs(nilfs, sb);
1080         if (err)
1081                 goto failed_nilfs;
1082 
1083         cno = nilfs_last_cno(nilfs);
1084         err = nilfs_attach_checkpoint(sb, cno, true, &fsroot);
1085         if (err) {
1086                 printk(KERN_ERR "NILFS: error loading last checkpoint "
1087                        "(checkpoint number=%llu).\n", (unsigned long long)cno);
1088                 goto failed_unload;
1089         }
1090 
1091         if (!(sb->s_flags & MS_RDONLY)) {
1092                 err = nilfs_attach_log_writer(sb, fsroot);
1093                 if (err)
1094                         goto failed_checkpoint;
1095         }
1096 
1097         err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
1098         if (err)
1099                 goto failed_segctor;
1100 
1101         nilfs_put_root(fsroot);
1102 
1103         if (!(sb->s_flags & MS_RDONLY)) {
1104                 down_write(&nilfs->ns_sem);
1105                 nilfs_setup_super(sb, true);
1106                 up_write(&nilfs->ns_sem);
1107         }
1108 
1109         return 0;
1110 
1111  failed_segctor:
1112         nilfs_detach_log_writer(sb);
1113 
1114  failed_checkpoint:
1115         nilfs_put_root(fsroot);
1116 
1117  failed_unload:
1118         iput(nilfs->ns_sufile);
1119         iput(nilfs->ns_cpfile);
1120         iput(nilfs->ns_dat);
1121 
1122  failed_nilfs:
1123         destroy_nilfs(nilfs);
1124         return err;
1125 }
1126 
1127 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
1128 {
1129         struct the_nilfs *nilfs = sb->s_fs_info;
1130         unsigned long old_sb_flags;
1131         unsigned long old_mount_opt;
1132         int err;
1133 
1134         sync_filesystem(sb);
1135         old_sb_flags = sb->s_flags;
1136         old_mount_opt = nilfs->ns_mount_opt;
1137 
1138         if (!parse_options(data, sb, 1)) {
1139                 err = -EINVAL;
1140                 goto restore_opts;
1141         }
1142         sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
1143 
1144         err = -EINVAL;
1145 
1146         if (!nilfs_valid_fs(nilfs)) {
1147                 printk(KERN_WARNING "NILFS (device %s): couldn't "
1148                        "remount because the filesystem is in an "
1149                        "incomplete recovery state.\n", sb->s_id);
1150                 goto restore_opts;
1151         }
1152 
1153         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1154                 goto out;
1155         if (*flags & MS_RDONLY) {
1156                 /* Shutting down log writer */
1157                 nilfs_detach_log_writer(sb);
1158                 sb->s_flags |= MS_RDONLY;
1159 
1160                 /*
1161                  * Remounting a valid RW partition RDONLY, so set
1162                  * the RDONLY flag and then mark the partition as valid again.
1163                  */
1164                 down_write(&nilfs->ns_sem);
1165                 nilfs_cleanup_super(sb);
1166                 up_write(&nilfs->ns_sem);
1167         } else {
1168                 __u64 features;
1169                 struct nilfs_root *root;
1170 
1171                 /*
1172                  * Mounting a RDONLY partition read-write, so reread and
1173                  * store the current valid flag.  (It may have been changed
1174                  * by fsck since we originally mounted the partition.)
1175                  */
1176                 down_read(&nilfs->ns_sem);
1177                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1178                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
1179                 up_read(&nilfs->ns_sem);
1180                 if (features) {
1181                         printk(KERN_WARNING "NILFS (device %s): couldn't "
1182                                "remount RDWR because of unsupported optional "
1183                                "features (%llx)\n",
1184                                sb->s_id, (unsigned long long)features);
1185                         err = -EROFS;
1186                         goto restore_opts;
1187                 }
1188 
1189                 sb->s_flags &= ~MS_RDONLY;
1190 
1191                 root = NILFS_I(d_inode(sb->s_root))->i_root;
1192                 err = nilfs_attach_log_writer(sb, root);
1193                 if (err)
1194                         goto restore_opts;
1195 
1196                 down_write(&nilfs->ns_sem);
1197                 nilfs_setup_super(sb, true);
1198                 up_write(&nilfs->ns_sem);
1199         }
1200  out:
1201         return 0;
1202 
1203  restore_opts:
1204         sb->s_flags = old_sb_flags;
1205         nilfs->ns_mount_opt = old_mount_opt;
1206         return err;
1207 }
1208 
1209 struct nilfs_super_data {
1210         struct block_device *bdev;
1211         __u64 cno;
1212         int flags;
1213 };
1214 
1215 /**
1216  * nilfs_identify - pre-read mount options needed to identify mount instance
1217  * @data: mount options
1218  * @sd: nilfs_super_data
1219  */
1220 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1221 {
1222         char *p, *options = data;
1223         substring_t args[MAX_OPT_ARGS];
1224         int token;
1225         int ret = 0;
1226 
1227         do {
1228                 p = strsep(&options, ",");
1229                 if (p != NULL && *p) {
1230                         token = match_token(p, tokens, args);
1231                         if (token == Opt_snapshot) {
1232                                 if (!(sd->flags & MS_RDONLY)) {
1233                                         ret++;
1234                                 } else {
1235                                         sd->cno = simple_strtoull(args[0].from,
1236                                                                   NULL, 0);
1237                                         /*
1238                                          * No need to see the end pointer;
1239                                          * match_token() has done syntax
1240                                          * checking.
1241                                          */
1242                                         if (sd->cno == 0)
1243                                                 ret++;
1244                                 }
1245                         }
1246                         if (ret)
1247                                 printk(KERN_ERR
1248                                        "NILFS: invalid mount option: %s\n", p);
1249                 }
1250                 if (!options)
1251                         break;
1252                 BUG_ON(options == data);
1253                 *(options - 1) = ',';
1254         } while (!ret);
1255         return ret;
1256 }
1257 
1258 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1259 {
1260         s->s_bdev = data;
1261         s->s_dev = s->s_bdev->bd_dev;
1262         return 0;
1263 }
1264 
1265 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1266 {
1267         return (void *)s->s_bdev == data;
1268 }
1269 
1270 static struct dentry *
1271 nilfs_mount(struct file_system_type *fs_type, int flags,
1272              const char *dev_name, void *data)
1273 {
1274         struct nilfs_super_data sd;
1275         struct super_block *s;
1276         fmode_t mode = FMODE_READ | FMODE_EXCL;
1277         struct dentry *root_dentry;
1278         int err, s_new = false;
1279 
1280         if (!(flags & MS_RDONLY))
1281                 mode |= FMODE_WRITE;
1282 
1283         sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
1284         if (IS_ERR(sd.bdev))
1285                 return ERR_CAST(sd.bdev);
1286 
1287         sd.cno = 0;
1288         sd.flags = flags;
1289         if (nilfs_identify((char *)data, &sd)) {
1290                 err = -EINVAL;
1291                 goto failed;
1292         }
1293 
1294         /*
1295          * once the super is inserted into the list by sget, s_umount
1296          * will protect the lockfs code from trying to start a snapshot
1297          * while we are mounting
1298          */
1299         mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
1300         if (sd.bdev->bd_fsfreeze_count > 0) {
1301                 mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1302                 err = -EBUSY;
1303                 goto failed;
1304         }
1305         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, flags,
1306                  sd.bdev);
1307         mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1308         if (IS_ERR(s)) {
1309                 err = PTR_ERR(s);
1310                 goto failed;
1311         }
1312 
1313         if (!s->s_root) {
1314                 s_new = true;
1315 
1316                 /* New superblock instance created */
1317                 s->s_mode = mode;
1318                 snprintf(s->s_id, sizeof(s->s_id), "%pg", sd.bdev);
1319                 sb_set_blocksize(s, block_size(sd.bdev));
1320 
1321                 err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
1322                 if (err)
1323                         goto failed_super;
1324 
1325                 s->s_flags |= MS_ACTIVE;
1326         } else if (!sd.cno) {
1327                 if (nilfs_tree_is_busy(s->s_root)) {
1328                         if ((flags ^ s->s_flags) & MS_RDONLY) {
1329                                 printk(KERN_ERR "NILFS: the device already "
1330                                        "has a %s mount.\n",
1331                                        (s->s_flags & MS_RDONLY) ?
1332                                        "read-only" : "read/write");
1333                                 err = -EBUSY;
1334                                 goto failed_super;
1335                         }
1336                 } else {
1337                         /*
1338                          * Try remount to setup mount states if the current
1339                          * tree is not mounted and only snapshots use this sb.
1340                          */
1341                         err = nilfs_remount(s, &flags, data);
1342                         if (err)
1343                                 goto failed_super;
1344                 }
1345         }
1346 
1347         if (sd.cno) {
1348                 err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
1349                 if (err)
1350                         goto failed_super;
1351         } else {
1352                 root_dentry = dget(s->s_root);
1353         }
1354 
1355         if (!s_new)
1356                 blkdev_put(sd.bdev, mode);
1357 
1358         return root_dentry;
1359 
1360  failed_super:
1361         deactivate_locked_super(s);
1362 
1363  failed:
1364         if (!s_new)
1365                 blkdev_put(sd.bdev, mode);
1366         return ERR_PTR(err);
1367 }
1368 
1369 struct file_system_type nilfs_fs_type = {
1370         .owner    = THIS_MODULE,
1371         .name     = "nilfs2",
1372         .mount    = nilfs_mount,
1373         .kill_sb  = kill_block_super,
1374         .fs_flags = FS_REQUIRES_DEV,
1375 };
1376 MODULE_ALIAS_FS("nilfs2");
1377 
1378 static void nilfs_inode_init_once(void *obj)
1379 {
1380         struct nilfs_inode_info *ii = obj;
1381 
1382         INIT_LIST_HEAD(&ii->i_dirty);
1383 #ifdef CONFIG_NILFS_XATTR
1384         init_rwsem(&ii->xattr_sem);
1385 #endif
1386         address_space_init_once(&ii->i_btnode_cache);
1387         ii->i_bmap = &ii->i_bmap_data;
1388         inode_init_once(&ii->vfs_inode);
1389 }
1390 
1391 static void nilfs_segbuf_init_once(void *obj)
1392 {
1393         memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1394 }
1395 
1396 static void nilfs_destroy_cachep(void)
1397 {
1398         /*
1399          * Make sure all delayed rcu free inodes are flushed before we
1400          * destroy cache.
1401          */
1402         rcu_barrier();
1403 
1404         kmem_cache_destroy(nilfs_inode_cachep);
1405         kmem_cache_destroy(nilfs_transaction_cachep);
1406         kmem_cache_destroy(nilfs_segbuf_cachep);
1407         kmem_cache_destroy(nilfs_btree_path_cache);
1408 }
1409 
1410 static int __init nilfs_init_cachep(void)
1411 {
1412         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1413                         sizeof(struct nilfs_inode_info), 0,
1414                         SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
1415                         nilfs_inode_init_once);
1416         if (!nilfs_inode_cachep)
1417                 goto fail;
1418 
1419         nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1420                         sizeof(struct nilfs_transaction_info), 0,
1421                         SLAB_RECLAIM_ACCOUNT, NULL);
1422         if (!nilfs_transaction_cachep)
1423                 goto fail;
1424 
1425         nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1426                         sizeof(struct nilfs_segment_buffer), 0,
1427                         SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1428         if (!nilfs_segbuf_cachep)
1429                 goto fail;
1430 
1431         nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1432                         sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1433                         0, 0, NULL);
1434         if (!nilfs_btree_path_cache)
1435                 goto fail;
1436 
1437         return 0;
1438 
1439 fail:
1440         nilfs_destroy_cachep();
1441         return -ENOMEM;
1442 }
1443 
1444 static int __init init_nilfs_fs(void)
1445 {
1446         int err;
1447 
1448         err = nilfs_init_cachep();
1449         if (err)
1450                 goto fail;
1451 
1452         err = nilfs_sysfs_init();
1453         if (err)
1454                 goto free_cachep;
1455 
1456         err = register_filesystem(&nilfs_fs_type);
1457         if (err)
1458                 goto deinit_sysfs_entry;
1459 
1460         printk(KERN_INFO "NILFS version 2 loaded\n");
1461         return 0;
1462 
1463 deinit_sysfs_entry:
1464         nilfs_sysfs_exit();
1465 free_cachep:
1466         nilfs_destroy_cachep();
1467 fail:
1468         return err;
1469 }
1470 
1471 static void __exit exit_nilfs_fs(void)
1472 {
1473         nilfs_destroy_cachep();
1474         nilfs_sysfs_exit();
1475         unregister_filesystem(&nilfs_fs_type);
1476 }
1477 
1478 module_init(init_nilfs_fs)
1479 module_exit(exit_nilfs_fs)
1480 

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