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TOMOYO Linux Cross Reference
Linux/fs/nilfs2/super.c

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  1 /*
  2  * super.c - NILFS module and super block management.
  3  *
  4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
  5  *
  6  * This program is free software; you can redistribute it and/or modify
  7  * it under the terms of the GNU General Public License as published by
  8  * the Free Software Foundation; either version 2 of the License, or
  9  * (at your option) any later version.
 10  *
 11  * This program is distributed in the hope that it will be useful,
 12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 14  * GNU General Public License for more details.
 15  *
 16  * You should have received a copy of the GNU General Public License
 17  * along with this program; if not, write to the Free Software
 18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 19  *
 20  * Written by Ryusuke Konishi <ryusuke@osrg.net>
 21  */
 22 /*
 23  *  linux/fs/ext2/super.c
 24  *
 25  * Copyright (C) 1992, 1993, 1994, 1995
 26  * Remy Card (card@masi.ibp.fr)
 27  * Laboratoire MASI - Institut Blaise Pascal
 28  * Universite Pierre et Marie Curie (Paris VI)
 29  *
 30  *  from
 31  *
 32  *  linux/fs/minix/inode.c
 33  *
 34  *  Copyright (C) 1991, 1992  Linus Torvalds
 35  *
 36  *  Big-endian to little-endian byte-swapping/bitmaps by
 37  *        David S. Miller (davem@caip.rutgers.edu), 1995
 38  */
 39 
 40 #include <linux/module.h>
 41 #include <linux/string.h>
 42 #include <linux/slab.h>
 43 #include <linux/init.h>
 44 #include <linux/blkdev.h>
 45 #include <linux/parser.h>
 46 #include <linux/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         if (mdi) {
179                 kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
180                 kfree(mdi);
181         }
182         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
183 }
184 
185 void nilfs_destroy_inode(struct inode *inode)
186 {
187         call_rcu(&inode->i_rcu, nilfs_i_callback);
188 }
189 
190 static int nilfs_sync_super(struct super_block *sb, int flag)
191 {
192         struct the_nilfs *nilfs = sb->s_fs_info;
193         int err;
194 
195  retry:
196         set_buffer_dirty(nilfs->ns_sbh[0]);
197         if (nilfs_test_opt(nilfs, BARRIER)) {
198                 err = __sync_dirty_buffer(nilfs->ns_sbh[0],
199                                           WRITE_SYNC | WRITE_FLUSH_FUA);
200         } else {
201                 err = sync_dirty_buffer(nilfs->ns_sbh[0]);
202         }
203 
204         if (unlikely(err)) {
205                 printk(KERN_ERR
206                        "NILFS: unable to write superblock (err=%d)\n", err);
207                 if (err == -EIO && nilfs->ns_sbh[1]) {
208                         /*
209                          * sbp[0] points to newer log than sbp[1],
210                          * so copy sbp[0] to sbp[1] to take over sbp[0].
211                          */
212                         memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
213                                nilfs->ns_sbsize);
214                         nilfs_fall_back_super_block(nilfs);
215                         goto retry;
216                 }
217         } else {
218                 struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
219 
220                 nilfs->ns_sbwcount++;
221 
222                 /*
223                  * The latest segment becomes trailable from the position
224                  * written in superblock.
225                  */
226                 clear_nilfs_discontinued(nilfs);
227 
228                 /* update GC protection for recent segments */
229                 if (nilfs->ns_sbh[1]) {
230                         if (flag == NILFS_SB_COMMIT_ALL) {
231                                 set_buffer_dirty(nilfs->ns_sbh[1]);
232                                 if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
233                                         goto out;
234                         }
235                         if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
236                             le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
237                                 sbp = nilfs->ns_sbp[1];
238                 }
239 
240                 spin_lock(&nilfs->ns_last_segment_lock);
241                 nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
242                 spin_unlock(&nilfs->ns_last_segment_lock);
243         }
244  out:
245         return err;
246 }
247 
248 void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
249                           struct the_nilfs *nilfs)
250 {
251         sector_t nfreeblocks;
252 
253         /* nilfs->ns_sem must be locked by the caller. */
254         nilfs_count_free_blocks(nilfs, &nfreeblocks);
255         sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
256 
257         spin_lock(&nilfs->ns_last_segment_lock);
258         sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
259         sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
260         sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
261         spin_unlock(&nilfs->ns_last_segment_lock);
262 }
263 
264 struct nilfs_super_block **nilfs_prepare_super(struct super_block *sb,
265                                                int flip)
266 {
267         struct the_nilfs *nilfs = sb->s_fs_info;
268         struct nilfs_super_block **sbp = nilfs->ns_sbp;
269 
270         /* nilfs->ns_sem must be locked by the caller. */
271         if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
272                 if (sbp[1] &&
273                     sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
274                         memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
275                 } else {
276                         printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
277                                sb->s_id);
278                         return NULL;
279                 }
280         } else if (sbp[1] &&
281                    sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
282                         memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
283         }
284 
285         if (flip && sbp[1])
286                 nilfs_swap_super_block(nilfs);
287 
288         return sbp;
289 }
290 
291 int nilfs_commit_super(struct super_block *sb, int flag)
292 {
293         struct the_nilfs *nilfs = sb->s_fs_info;
294         struct nilfs_super_block **sbp = nilfs->ns_sbp;
295         time_t t;
296 
297         /* nilfs->ns_sem must be locked by the caller. */
298         t = get_seconds();
299         nilfs->ns_sbwtime = t;
300         sbp[0]->s_wtime = cpu_to_le64(t);
301         sbp[0]->s_sum = 0;
302         sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
303                                              (unsigned char *)sbp[0],
304                                              nilfs->ns_sbsize));
305         if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
306                 sbp[1]->s_wtime = sbp[0]->s_wtime;
307                 sbp[1]->s_sum = 0;
308                 sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
309                                             (unsigned char *)sbp[1],
310                                             nilfs->ns_sbsize));
311         }
312         clear_nilfs_sb_dirty(nilfs);
313         return nilfs_sync_super(sb, flag);
314 }
315 
316 /**
317  * nilfs_cleanup_super() - write filesystem state for cleanup
318  * @sb: super block instance to be unmounted or degraded to read-only
319  *
320  * This function restores state flags in the on-disk super block.
321  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
322  * filesystem was not clean previously.
323  */
324 int nilfs_cleanup_super(struct super_block *sb)
325 {
326         struct the_nilfs *nilfs = sb->s_fs_info;
327         struct nilfs_super_block **sbp;
328         int flag = NILFS_SB_COMMIT;
329         int ret = -EIO;
330 
331         sbp = nilfs_prepare_super(sb, 0);
332         if (sbp) {
333                 sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
334                 nilfs_set_log_cursor(sbp[0], nilfs);
335                 if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
336                         /*
337                          * make the "clean" flag also to the opposite
338                          * super block if both super blocks point to
339                          * the same checkpoint.
340                          */
341                         sbp[1]->s_state = sbp[0]->s_state;
342                         flag = NILFS_SB_COMMIT_ALL;
343                 }
344                 ret = nilfs_commit_super(sb, flag);
345         }
346         return ret;
347 }
348 
349 /**
350  * nilfs_move_2nd_super - relocate secondary super block
351  * @sb: super block instance
352  * @sb2off: new offset of the secondary super block (in bytes)
353  */
354 static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
355 {
356         struct the_nilfs *nilfs = sb->s_fs_info;
357         struct buffer_head *nsbh;
358         struct nilfs_super_block *nsbp;
359         sector_t blocknr, newblocknr;
360         unsigned long offset;
361         int sb2i = -1;  /* array index of the secondary superblock */
362         int ret = 0;
363 
364         /* nilfs->ns_sem must be locked by the caller. */
365         if (nilfs->ns_sbh[1] &&
366             nilfs->ns_sbh[1]->b_blocknr > nilfs->ns_first_data_block) {
367                 sb2i = 1;
368                 blocknr = nilfs->ns_sbh[1]->b_blocknr;
369         } else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
370                 sb2i = 0;
371                 blocknr = nilfs->ns_sbh[0]->b_blocknr;
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         return err;
518 }
519 
520 int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
521                             struct nilfs_root **rootp)
522 {
523         struct the_nilfs *nilfs = sb->s_fs_info;
524         struct nilfs_root *root;
525         struct nilfs_checkpoint *raw_cp;
526         struct buffer_head *bh_cp;
527         int err = -ENOMEM;
528 
529         root = nilfs_find_or_create_root(
530                 nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
531         if (!root)
532                 return err;
533 
534         if (root->ifile)
535                 goto reuse; /* already attached checkpoint */
536 
537         down_read(&nilfs->ns_segctor_sem);
538         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
539                                           &bh_cp);
540         up_read(&nilfs->ns_segctor_sem);
541         if (unlikely(err)) {
542                 if (err == -ENOENT || err == -EINVAL) {
543                         printk(KERN_ERR
544                                "NILFS: Invalid checkpoint "
545                                "(checkpoint number=%llu)\n",
546                                (unsigned long long)cno);
547                         err = -EINVAL;
548                 }
549                 goto failed;
550         }
551 
552         err = nilfs_ifile_read(sb, root, nilfs->ns_inode_size,
553                                &raw_cp->cp_ifile_inode, &root->ifile);
554         if (err)
555                 goto failed_bh;
556 
557         atomic_set(&root->inodes_count, le64_to_cpu(raw_cp->cp_inodes_count));
558         atomic_set(&root->blocks_count, le64_to_cpu(raw_cp->cp_blocks_count));
559 
560         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
561 
562  reuse:
563         *rootp = root;
564         return 0;
565 
566  failed_bh:
567         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
568  failed:
569         nilfs_put_root(root);
570 
571         return err;
572 }
573 
574 static int nilfs_freeze(struct super_block *sb)
575 {
576         struct the_nilfs *nilfs = sb->s_fs_info;
577         int err;
578 
579         if (sb->s_flags & MS_RDONLY)
580                 return 0;
581 
582         /* Mark super block clean */
583         down_write(&nilfs->ns_sem);
584         err = nilfs_cleanup_super(sb);
585         up_write(&nilfs->ns_sem);
586         return err;
587 }
588 
589 static int nilfs_unfreeze(struct super_block *sb)
590 {
591         struct the_nilfs *nilfs = sb->s_fs_info;
592 
593         if (sb->s_flags & MS_RDONLY)
594                 return 0;
595 
596         down_write(&nilfs->ns_sem);
597         nilfs_setup_super(sb, false);
598         up_write(&nilfs->ns_sem);
599         return 0;
600 }
601 
602 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
603 {
604         struct super_block *sb = dentry->d_sb;
605         struct nilfs_root *root = NILFS_I(dentry->d_inode)->i_root;
606         struct the_nilfs *nilfs = root->nilfs;
607         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
608         unsigned long long blocks;
609         unsigned long overhead;
610         unsigned long nrsvblocks;
611         sector_t nfreeblocks;
612         int err;
613 
614         /*
615          * Compute all of the segment blocks
616          *
617          * The blocks before first segment and after last segment
618          * are excluded.
619          */
620         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
621                 - nilfs->ns_first_data_block;
622         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
623 
624         /*
625          * Compute the overhead
626          *
627          * When distributing meta data blocks outside segment structure,
628          * We must count them as the overhead.
629          */
630         overhead = 0;
631 
632         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
633         if (unlikely(err))
634                 return err;
635 
636         buf->f_type = NILFS_SUPER_MAGIC;
637         buf->f_bsize = sb->s_blocksize;
638         buf->f_blocks = blocks - overhead;
639         buf->f_bfree = nfreeblocks;
640         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
641                 (buf->f_bfree - nrsvblocks) : 0;
642         buf->f_files = atomic_read(&root->inodes_count);
643         buf->f_ffree = 0; /* nilfs_count_free_inodes(sb); */
644         buf->f_namelen = NILFS_NAME_LEN;
645         buf->f_fsid.val[0] = (u32)id;
646         buf->f_fsid.val[1] = (u32)(id >> 32);
647 
648         return 0;
649 }
650 
651 static int nilfs_show_options(struct seq_file *seq, struct dentry *dentry)
652 {
653         struct super_block *sb = dentry->d_sb;
654         struct the_nilfs *nilfs = sb->s_fs_info;
655         struct nilfs_root *root = NILFS_I(dentry->d_inode)->i_root;
656 
657         if (!nilfs_test_opt(nilfs, BARRIER))
658                 seq_puts(seq, ",nobarrier");
659         if (root->cno != NILFS_CPTREE_CURRENT_CNO)
660                 seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
661         if (nilfs_test_opt(nilfs, ERRORS_PANIC))
662                 seq_puts(seq, ",errors=panic");
663         if (nilfs_test_opt(nilfs, ERRORS_CONT))
664                 seq_puts(seq, ",errors=continue");
665         if (nilfs_test_opt(nilfs, STRICT_ORDER))
666                 seq_puts(seq, ",order=strict");
667         if (nilfs_test_opt(nilfs, NORECOVERY))
668                 seq_puts(seq, ",norecovery");
669         if (nilfs_test_opt(nilfs, DISCARD))
670                 seq_puts(seq, ",discard");
671 
672         return 0;
673 }
674 
675 static const struct super_operations nilfs_sops = {
676         .alloc_inode    = nilfs_alloc_inode,
677         .destroy_inode  = nilfs_destroy_inode,
678         .dirty_inode    = nilfs_dirty_inode,
679         .evict_inode    = nilfs_evict_inode,
680         .put_super      = nilfs_put_super,
681         .sync_fs        = nilfs_sync_fs,
682         .freeze_fs      = nilfs_freeze,
683         .unfreeze_fs    = nilfs_unfreeze,
684         .statfs         = nilfs_statfs,
685         .remount_fs     = nilfs_remount,
686         .show_options = nilfs_show_options
687 };
688 
689 enum {
690         Opt_err_cont, Opt_err_panic, Opt_err_ro,
691         Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
692         Opt_discard, Opt_nodiscard, Opt_err,
693 };
694 
695 static match_table_t tokens = {
696         {Opt_err_cont, "errors=continue"},
697         {Opt_err_panic, "errors=panic"},
698         {Opt_err_ro, "errors=remount-ro"},
699         {Opt_barrier, "barrier"},
700         {Opt_nobarrier, "nobarrier"},
701         {Opt_snapshot, "cp=%u"},
702         {Opt_order, "order=%s"},
703         {Opt_norecovery, "norecovery"},
704         {Opt_discard, "discard"},
705         {Opt_nodiscard, "nodiscard"},
706         {Opt_err, NULL}
707 };
708 
709 static int parse_options(char *options, struct super_block *sb, int is_remount)
710 {
711         struct the_nilfs *nilfs = sb->s_fs_info;
712         char *p;
713         substring_t args[MAX_OPT_ARGS];
714 
715         if (!options)
716                 return 1;
717 
718         while ((p = strsep(&options, ",")) != NULL) {
719                 int token;
720                 if (!*p)
721                         continue;
722 
723                 token = match_token(p, tokens, args);
724                 switch (token) {
725                 case Opt_barrier:
726                         nilfs_set_opt(nilfs, BARRIER);
727                         break;
728                 case Opt_nobarrier:
729                         nilfs_clear_opt(nilfs, BARRIER);
730                         break;
731                 case Opt_order:
732                         if (strcmp(args[0].from, "relaxed") == 0)
733                                 /* Ordered data semantics */
734                                 nilfs_clear_opt(nilfs, STRICT_ORDER);
735                         else if (strcmp(args[0].from, "strict") == 0)
736                                 /* Strict in-order semantics */
737                                 nilfs_set_opt(nilfs, STRICT_ORDER);
738                         else
739                                 return 0;
740                         break;
741                 case Opt_err_panic:
742                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_PANIC);
743                         break;
744                 case Opt_err_ro:
745                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_RO);
746                         break;
747                 case Opt_err_cont:
748                         nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_CONT);
749                         break;
750                 case Opt_snapshot:
751                         if (is_remount) {
752                                 printk(KERN_ERR
753                                        "NILFS: \"%s\" option is invalid "
754                                        "for remount.\n", p);
755                                 return 0;
756                         }
757                         break;
758                 case Opt_norecovery:
759                         nilfs_set_opt(nilfs, NORECOVERY);
760                         break;
761                 case Opt_discard:
762                         nilfs_set_opt(nilfs, DISCARD);
763                         break;
764                 case Opt_nodiscard:
765                         nilfs_clear_opt(nilfs, DISCARD);
766                         break;
767                 default:
768                         printk(KERN_ERR
769                                "NILFS: Unrecognized mount option \"%s\"\n", p);
770                         return 0;
771                 }
772         }
773         return 1;
774 }
775 
776 static inline void
777 nilfs_set_default_options(struct super_block *sb,
778                           struct nilfs_super_block *sbp)
779 {
780         struct the_nilfs *nilfs = sb->s_fs_info;
781 
782         nilfs->ns_mount_opt =
783                 NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
784 }
785 
786 static int nilfs_setup_super(struct super_block *sb, int is_mount)
787 {
788         struct the_nilfs *nilfs = sb->s_fs_info;
789         struct nilfs_super_block **sbp;
790         int max_mnt_count;
791         int mnt_count;
792 
793         /* nilfs->ns_sem must be locked by the caller. */
794         sbp = nilfs_prepare_super(sb, 0);
795         if (!sbp)
796                 return -EIO;
797 
798         if (!is_mount)
799                 goto skip_mount_setup;
800 
801         max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
802         mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
803 
804         if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
805                 printk(KERN_WARNING
806                        "NILFS warning: mounting fs with errors\n");
807 #if 0
808         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
809                 printk(KERN_WARNING
810                        "NILFS warning: maximal mount count reached\n");
811 #endif
812         }
813         if (!max_mnt_count)
814                 sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
815 
816         sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
817         sbp[0]->s_mtime = cpu_to_le64(get_seconds());
818 
819 skip_mount_setup:
820         sbp[0]->s_state =
821                 cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
822         /* synchronize sbp[1] with sbp[0] */
823         if (sbp[1])
824                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
825         return nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
826 }
827 
828 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
829                                                  u64 pos, int blocksize,
830                                                  struct buffer_head **pbh)
831 {
832         unsigned long long sb_index = pos;
833         unsigned long offset;
834 
835         offset = do_div(sb_index, blocksize);
836         *pbh = sb_bread(sb, sb_index);
837         if (!*pbh)
838                 return NULL;
839         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
840 }
841 
842 int nilfs_store_magic_and_option(struct super_block *sb,
843                                  struct nilfs_super_block *sbp,
844                                  char *data)
845 {
846         struct the_nilfs *nilfs = sb->s_fs_info;
847 
848         sb->s_magic = le16_to_cpu(sbp->s_magic);
849 
850         /* FS independent flags */
851 #ifdef NILFS_ATIME_DISABLE
852         sb->s_flags |= MS_NOATIME;
853 #endif
854 
855         nilfs_set_default_options(sb, sbp);
856 
857         nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
858         nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
859         nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
860         nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
861 
862         return !parse_options(data, sb, 0) ? -EINVAL : 0 ;
863 }
864 
865 int nilfs_check_feature_compatibility(struct super_block *sb,
866                                       struct nilfs_super_block *sbp)
867 {
868         __u64 features;
869 
870         features = le64_to_cpu(sbp->s_feature_incompat) &
871                 ~NILFS_FEATURE_INCOMPAT_SUPP;
872         if (features) {
873                 printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
874                        "optional features (%llx)\n",
875                        (unsigned long long)features);
876                 return -EINVAL;
877         }
878         features = le64_to_cpu(sbp->s_feature_compat_ro) &
879                 ~NILFS_FEATURE_COMPAT_RO_SUPP;
880         if (!(sb->s_flags & MS_RDONLY) && features) {
881                 printk(KERN_ERR "NILFS: couldn't mount RDWR because of "
882                        "unsupported optional features (%llx)\n",
883                        (unsigned long long)features);
884                 return -EINVAL;
885         }
886         return 0;
887 }
888 
889 static int nilfs_get_root_dentry(struct super_block *sb,
890                                  struct nilfs_root *root,
891                                  struct dentry **root_dentry)
892 {
893         struct inode *inode;
894         struct dentry *dentry;
895         int ret = 0;
896 
897         inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
898         if (IS_ERR(inode)) {
899                 printk(KERN_ERR "NILFS: get root inode failed\n");
900                 ret = PTR_ERR(inode);
901                 goto out;
902         }
903         if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
904                 iput(inode);
905                 printk(KERN_ERR "NILFS: corrupt root inode.\n");
906                 ret = -EINVAL;
907                 goto out;
908         }
909 
910         if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
911                 dentry = d_find_alias(inode);
912                 if (!dentry) {
913                         dentry = d_make_root(inode);
914                         if (!dentry) {
915                                 ret = -ENOMEM;
916                                 goto failed_dentry;
917                         }
918                 } else {
919                         iput(inode);
920                 }
921         } else {
922                 dentry = d_obtain_alias(inode);
923                 if (IS_ERR(dentry)) {
924                         ret = PTR_ERR(dentry);
925                         goto failed_dentry;
926                 }
927         }
928         *root_dentry = dentry;
929  out:
930         return ret;
931 
932  failed_dentry:
933         printk(KERN_ERR "NILFS: get root dentry failed\n");
934         goto out;
935 }
936 
937 static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
938                                  struct dentry **root_dentry)
939 {
940         struct the_nilfs *nilfs = s->s_fs_info;
941         struct nilfs_root *root;
942         int ret;
943 
944         mutex_lock(&nilfs->ns_snapshot_mount_mutex);
945 
946         down_read(&nilfs->ns_segctor_sem);
947         ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
948         up_read(&nilfs->ns_segctor_sem);
949         if (ret < 0) {
950                 ret = (ret == -ENOENT) ? -EINVAL : ret;
951                 goto out;
952         } else if (!ret) {
953                 printk(KERN_ERR "NILFS: The specified checkpoint is "
954                        "not a snapshot (checkpoint number=%llu).\n",
955                        (unsigned long long)cno);
956                 ret = -EINVAL;
957                 goto out;
958         }
959 
960         ret = nilfs_attach_checkpoint(s, cno, false, &root);
961         if (ret) {
962                 printk(KERN_ERR "NILFS: error loading snapshot "
963                        "(checkpoint number=%llu).\n",
964                (unsigned long long)cno);
965                 goto out;
966         }
967         ret = nilfs_get_root_dentry(s, root, root_dentry);
968         nilfs_put_root(root);
969  out:
970         mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
971         return ret;
972 }
973 
974 static int nilfs_tree_was_touched(struct dentry *root_dentry)
975 {
976         return root_dentry->d_count > 1;
977 }
978 
979 /**
980  * nilfs_try_to_shrink_tree() - try to shrink dentries of a checkpoint
981  * @root_dentry: root dentry of the tree to be shrunk
982  *
983  * This function returns true if the tree was in-use.
984  */
985 static int nilfs_try_to_shrink_tree(struct dentry *root_dentry)
986 {
987         if (have_submounts(root_dentry))
988                 return true;
989         shrink_dcache_parent(root_dentry);
990         return nilfs_tree_was_touched(root_dentry);
991 }
992 
993 int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
994 {
995         struct the_nilfs *nilfs = sb->s_fs_info;
996         struct nilfs_root *root;
997         struct inode *inode;
998         struct dentry *dentry;
999         int ret;
1000 
1001         if (cno < 0 || cno > nilfs->ns_cno)
1002                 return false;
1003 
1004         if (cno >= nilfs_last_cno(nilfs))
1005                 return true;    /* protect recent checkpoints */
1006 
1007         ret = false;
1008         root = nilfs_lookup_root(nilfs, cno);
1009         if (root) {
1010                 inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
1011                 if (inode) {
1012                         dentry = d_find_alias(inode);
1013                         if (dentry) {
1014                                 if (nilfs_tree_was_touched(dentry))
1015                                         ret = nilfs_try_to_shrink_tree(dentry);
1016                                 dput(dentry);
1017                         }
1018                         iput(inode);
1019                 }
1020                 nilfs_put_root(root);
1021         }
1022         return ret;
1023 }
1024 
1025 /**
1026  * nilfs_fill_super() - initialize a super block instance
1027  * @sb: super_block
1028  * @data: mount options
1029  * @silent: silent mode flag
1030  *
1031  * This function is called exclusively by nilfs->ns_mount_mutex.
1032  * So, the recovery process is protected from other simultaneous mounts.
1033  */
1034 static int
1035 nilfs_fill_super(struct super_block *sb, void *data, int silent)
1036 {
1037         struct the_nilfs *nilfs;
1038         struct nilfs_root *fsroot;
1039         struct backing_dev_info *bdi;
1040         __u64 cno;
1041         int err;
1042 
1043         nilfs = alloc_nilfs(sb->s_bdev);
1044         if (!nilfs)
1045                 return -ENOMEM;
1046 
1047         sb->s_fs_info = nilfs;
1048 
1049         err = init_nilfs(nilfs, sb, (char *)data);
1050         if (err)
1051                 goto failed_nilfs;
1052 
1053         sb->s_op = &nilfs_sops;
1054         sb->s_export_op = &nilfs_export_ops;
1055         sb->s_root = NULL;
1056         sb->s_time_gran = 1;
1057         sb->s_max_links = NILFS_LINK_MAX;
1058 
1059         bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
1060         sb->s_bdi = bdi ? : &default_backing_dev_info;
1061 
1062         err = load_nilfs(nilfs, sb);
1063         if (err)
1064                 goto failed_nilfs;
1065 
1066         cno = nilfs_last_cno(nilfs);
1067         err = nilfs_attach_checkpoint(sb, cno, true, &fsroot);
1068         if (err) {
1069                 printk(KERN_ERR "NILFS: error loading last checkpoint "
1070                        "(checkpoint number=%llu).\n", (unsigned long long)cno);
1071                 goto failed_unload;
1072         }
1073 
1074         if (!(sb->s_flags & MS_RDONLY)) {
1075                 err = nilfs_attach_log_writer(sb, fsroot);
1076                 if (err)
1077                         goto failed_checkpoint;
1078         }
1079 
1080         err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
1081         if (err)
1082                 goto failed_segctor;
1083 
1084         nilfs_put_root(fsroot);
1085 
1086         if (!(sb->s_flags & MS_RDONLY)) {
1087                 down_write(&nilfs->ns_sem);
1088                 nilfs_setup_super(sb, true);
1089                 up_write(&nilfs->ns_sem);
1090         }
1091 
1092         return 0;
1093 
1094  failed_segctor:
1095         nilfs_detach_log_writer(sb);
1096 
1097  failed_checkpoint:
1098         nilfs_put_root(fsroot);
1099 
1100  failed_unload:
1101         iput(nilfs->ns_sufile);
1102         iput(nilfs->ns_cpfile);
1103         iput(nilfs->ns_dat);
1104 
1105  failed_nilfs:
1106         destroy_nilfs(nilfs);
1107         return err;
1108 }
1109 
1110 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
1111 {
1112         struct the_nilfs *nilfs = sb->s_fs_info;
1113         unsigned long old_sb_flags;
1114         unsigned long old_mount_opt;
1115         int err;
1116 
1117         old_sb_flags = sb->s_flags;
1118         old_mount_opt = nilfs->ns_mount_opt;
1119 
1120         if (!parse_options(data, sb, 1)) {
1121                 err = -EINVAL;
1122                 goto restore_opts;
1123         }
1124         sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
1125 
1126         err = -EINVAL;
1127 
1128         if (!nilfs_valid_fs(nilfs)) {
1129                 printk(KERN_WARNING "NILFS (device %s): couldn't "
1130                        "remount because the filesystem is in an "
1131                        "incomplete recovery state.\n", sb->s_id);
1132                 goto restore_opts;
1133         }
1134 
1135         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1136                 goto out;
1137         if (*flags & MS_RDONLY) {
1138                 /* Shutting down log writer */
1139                 nilfs_detach_log_writer(sb);
1140                 sb->s_flags |= MS_RDONLY;
1141 
1142                 /*
1143                  * Remounting a valid RW partition RDONLY, so set
1144                  * the RDONLY flag and then mark the partition as valid again.
1145                  */
1146                 down_write(&nilfs->ns_sem);
1147                 nilfs_cleanup_super(sb);
1148                 up_write(&nilfs->ns_sem);
1149         } else {
1150                 __u64 features;
1151                 struct nilfs_root *root;
1152 
1153                 /*
1154                  * Mounting a RDONLY partition read-write, so reread and
1155                  * store the current valid flag.  (It may have been changed
1156                  * by fsck since we originally mounted the partition.)
1157                  */
1158                 down_read(&nilfs->ns_sem);
1159                 features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1160                         ~NILFS_FEATURE_COMPAT_RO_SUPP;
1161                 up_read(&nilfs->ns_sem);
1162                 if (features) {
1163                         printk(KERN_WARNING "NILFS (device %s): couldn't "
1164                                "remount RDWR because of unsupported optional "
1165                                "features (%llx)\n",
1166                                sb->s_id, (unsigned long long)features);
1167                         err = -EROFS;
1168                         goto restore_opts;
1169                 }
1170 
1171                 sb->s_flags &= ~MS_RDONLY;
1172 
1173                 root = NILFS_I(sb->s_root->d_inode)->i_root;
1174                 err = nilfs_attach_log_writer(sb, root);
1175                 if (err)
1176                         goto restore_opts;
1177 
1178                 down_write(&nilfs->ns_sem);
1179                 nilfs_setup_super(sb, true);
1180                 up_write(&nilfs->ns_sem);
1181         }
1182  out:
1183         return 0;
1184 
1185  restore_opts:
1186         sb->s_flags = old_sb_flags;
1187         nilfs->ns_mount_opt = old_mount_opt;
1188         return err;
1189 }
1190 
1191 struct nilfs_super_data {
1192         struct block_device *bdev;
1193         __u64 cno;
1194         int flags;
1195 };
1196 
1197 /**
1198  * nilfs_identify - pre-read mount options needed to identify mount instance
1199  * @data: mount options
1200  * @sd: nilfs_super_data
1201  */
1202 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1203 {
1204         char *p, *options = data;
1205         substring_t args[MAX_OPT_ARGS];
1206         int token;
1207         int ret = 0;
1208 
1209         do {
1210                 p = strsep(&options, ",");
1211                 if (p != NULL && *p) {
1212                         token = match_token(p, tokens, args);
1213                         if (token == Opt_snapshot) {
1214                                 if (!(sd->flags & MS_RDONLY)) {
1215                                         ret++;
1216                                 } else {
1217                                         sd->cno = simple_strtoull(args[0].from,
1218                                                                   NULL, 0);
1219                                         /*
1220                                          * No need to see the end pointer;
1221                                          * match_token() has done syntax
1222                                          * checking.
1223                                          */
1224                                         if (sd->cno == 0)
1225                                                 ret++;
1226                                 }
1227                         }
1228                         if (ret)
1229                                 printk(KERN_ERR
1230                                        "NILFS: invalid mount option: %s\n", p);
1231                 }
1232                 if (!options)
1233                         break;
1234                 BUG_ON(options == data);
1235                 *(options - 1) = ',';
1236         } while (!ret);
1237         return ret;
1238 }
1239 
1240 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1241 {
1242         s->s_bdev = data;
1243         s->s_dev = s->s_bdev->bd_dev;
1244         return 0;
1245 }
1246 
1247 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1248 {
1249         return (void *)s->s_bdev == data;
1250 }
1251 
1252 static struct dentry *
1253 nilfs_mount(struct file_system_type *fs_type, int flags,
1254              const char *dev_name, void *data)
1255 {
1256         struct nilfs_super_data sd;
1257         struct super_block *s;
1258         fmode_t mode = FMODE_READ | FMODE_EXCL;
1259         struct dentry *root_dentry;
1260         int err, s_new = false;
1261 
1262         if (!(flags & MS_RDONLY))
1263                 mode |= FMODE_WRITE;
1264 
1265         sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
1266         if (IS_ERR(sd.bdev))
1267                 return ERR_CAST(sd.bdev);
1268 
1269         sd.cno = 0;
1270         sd.flags = flags;
1271         if (nilfs_identify((char *)data, &sd)) {
1272                 err = -EINVAL;
1273                 goto failed;
1274         }
1275 
1276         /*
1277          * once the super is inserted into the list by sget, s_umount
1278          * will protect the lockfs code from trying to start a snapshot
1279          * while we are mounting
1280          */
1281         mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
1282         if (sd.bdev->bd_fsfreeze_count > 0) {
1283                 mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1284                 err = -EBUSY;
1285                 goto failed;
1286         }
1287         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, flags,
1288                  sd.bdev);
1289         mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1290         if (IS_ERR(s)) {
1291                 err = PTR_ERR(s);
1292                 goto failed;
1293         }
1294 
1295         if (!s->s_root) {
1296                 char b[BDEVNAME_SIZE];
1297 
1298                 s_new = true;
1299 
1300                 /* New superblock instance created */
1301                 s->s_mode = mode;
1302                 strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
1303                 sb_set_blocksize(s, block_size(sd.bdev));
1304 
1305                 err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
1306                 if (err)
1307                         goto failed_super;
1308 
1309                 s->s_flags |= MS_ACTIVE;
1310         } else if (!sd.cno) {
1311                 int busy = false;
1312 
1313                 if (nilfs_tree_was_touched(s->s_root)) {
1314                         busy = nilfs_try_to_shrink_tree(s->s_root);
1315                         if (busy && (flags ^ s->s_flags) & MS_RDONLY) {
1316                                 printk(KERN_ERR "NILFS: the device already "
1317                                        "has a %s mount.\n",
1318                                        (s->s_flags & MS_RDONLY) ?
1319                                        "read-only" : "read/write");
1320                                 err = -EBUSY;
1321                                 goto failed_super;
1322                         }
1323                 }
1324                 if (!busy) {
1325                         /*
1326                          * Try remount to setup mount states if the current
1327                          * tree is not mounted and only snapshots use this sb.
1328                          */
1329                         err = nilfs_remount(s, &flags, data);
1330                         if (err)
1331                                 goto failed_super;
1332                 }
1333         }
1334 
1335         if (sd.cno) {
1336                 err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
1337                 if (err)
1338                         goto failed_super;
1339         } else {
1340                 root_dentry = dget(s->s_root);
1341         }
1342 
1343         if (!s_new)
1344                 blkdev_put(sd.bdev, mode);
1345 
1346         return root_dentry;
1347 
1348  failed_super:
1349         deactivate_locked_super(s);
1350 
1351  failed:
1352         if (!s_new)
1353                 blkdev_put(sd.bdev, mode);
1354         return ERR_PTR(err);
1355 }
1356 
1357 struct file_system_type nilfs_fs_type = {
1358         .owner    = THIS_MODULE,
1359         .name     = "nilfs2",
1360         .mount    = nilfs_mount,
1361         .kill_sb  = kill_block_super,
1362         .fs_flags = FS_REQUIRES_DEV,
1363 };
1364 
1365 static void nilfs_inode_init_once(void *obj)
1366 {
1367         struct nilfs_inode_info *ii = obj;
1368 
1369         INIT_LIST_HEAD(&ii->i_dirty);
1370 #ifdef CONFIG_NILFS_XATTR
1371         init_rwsem(&ii->xattr_sem);
1372 #endif
1373         address_space_init_once(&ii->i_btnode_cache);
1374         ii->i_bmap = &ii->i_bmap_data;
1375         inode_init_once(&ii->vfs_inode);
1376 }
1377 
1378 static void nilfs_segbuf_init_once(void *obj)
1379 {
1380         memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1381 }
1382 
1383 static void nilfs_destroy_cachep(void)
1384 {
1385         /*
1386          * Make sure all delayed rcu free inodes are flushed before we
1387          * destroy cache.
1388          */
1389         rcu_barrier();
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)
1463 

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