xref: /linux/fs/nilfs2/super.c (revision cc4589ebfae6f8dbb5cf880a0a67eedab3416492)
1 /*
2  * super.c - NILFS module and super block management.
3  *
4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
19  *
20  * Written by Ryusuke Konishi <ryusuke@osrg.net>
21  */
22 /*
23  *  linux/fs/ext2/super.c
24  *
25  * Copyright (C) 1992, 1993, 1994, 1995
26  * Remy Card (card@masi.ibp.fr)
27  * Laboratoire MASI - Institut Blaise Pascal
28  * Universite Pierre et Marie Curie (Paris VI)
29  *
30  *  from
31  *
32  *  linux/fs/minix/inode.c
33  *
34  *  Copyright (C) 1991, 1992  Linus Torvalds
35  *
36  *  Big-endian to little-endian byte-swapping/bitmaps by
37  *        David S. Miller (davem@caip.rutgers.edu), 1995
38  */
39 
40 #include <linux/module.h>
41 #include <linux/string.h>
42 #include <linux/slab.h>
43 #include <linux/init.h>
44 #include <linux/blkdev.h>
45 #include <linux/parser.h>
46 #include <linux/random.h>
47 #include <linux/crc32.h>
48 #include <linux/smp_lock.h>
49 #include <linux/vfs.h>
50 #include <linux/writeback.h>
51 #include <linux/kobject.h>
52 #include <linux/exportfs.h>
53 #include <linux/seq_file.h>
54 #include <linux/mount.h>
55 #include "nilfs.h"
56 #include "mdt.h"
57 #include "alloc.h"
58 #include "btree.h"
59 #include "btnode.h"
60 #include "page.h"
61 #include "cpfile.h"
62 #include "ifile.h"
63 #include "dat.h"
64 #include "segment.h"
65 #include "segbuf.h"
66 
67 MODULE_AUTHOR("NTT Corp.");
68 MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
69 		   "(NILFS)");
70 MODULE_LICENSE("GPL");
71 
72 struct kmem_cache *nilfs_inode_cachep;
73 struct kmem_cache *nilfs_transaction_cachep;
74 struct kmem_cache *nilfs_segbuf_cachep;
75 struct kmem_cache *nilfs_btree_path_cache;
76 
77 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
78 
79 static void nilfs_set_error(struct nilfs_sb_info *sbi)
80 {
81 	struct the_nilfs *nilfs = sbi->s_nilfs;
82 	struct nilfs_super_block **sbp;
83 
84 	down_write(&nilfs->ns_sem);
85 	if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
86 		nilfs->ns_mount_state |= NILFS_ERROR_FS;
87 		sbp = nilfs_prepare_super(sbi, 0);
88 		if (likely(sbp)) {
89 			sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
90 			if (sbp[1])
91 				sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
92 			nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
93 		}
94 	}
95 	up_write(&nilfs->ns_sem);
96 }
97 
98 /**
99  * nilfs_error() - report failure condition on a filesystem
100  *
101  * nilfs_error() sets an ERROR_FS flag on the superblock as well as
102  * reporting an error message.  It should be called when NILFS detects
103  * incoherences or defects of meta data on disk.  As for sustainable
104  * errors such as a single-shot I/O error, nilfs_warning() or the printk()
105  * function should be used instead.
106  *
107  * The segment constructor must not call this function because it can
108  * kill itself.
109  */
110 void nilfs_error(struct super_block *sb, const char *function,
111 		 const char *fmt, ...)
112 {
113 	struct nilfs_sb_info *sbi = NILFS_SB(sb);
114 	va_list args;
115 
116 	va_start(args, fmt);
117 	printk(KERN_CRIT "NILFS error (device %s): %s: ", sb->s_id, function);
118 	vprintk(fmt, args);
119 	printk("\n");
120 	va_end(args);
121 
122 	if (!(sb->s_flags & MS_RDONLY)) {
123 		nilfs_set_error(sbi);
124 
125 		if (nilfs_test_opt(sbi, ERRORS_RO)) {
126 			printk(KERN_CRIT "Remounting filesystem read-only\n");
127 			sb->s_flags |= MS_RDONLY;
128 		}
129 	}
130 
131 	if (nilfs_test_opt(sbi, ERRORS_PANIC))
132 		panic("NILFS (device %s): panic forced after error\n",
133 		      sb->s_id);
134 }
135 
136 void nilfs_warning(struct super_block *sb, const char *function,
137 		   const char *fmt, ...)
138 {
139 	va_list args;
140 
141 	va_start(args, fmt);
142 	printk(KERN_WARNING "NILFS warning (device %s): %s: ",
143 	       sb->s_id, function);
144 	vprintk(fmt, args);
145 	printk("\n");
146 	va_end(args);
147 }
148 
149 
150 struct inode *nilfs_alloc_inode_common(struct the_nilfs *nilfs)
151 {
152 	struct nilfs_inode_info *ii;
153 
154 	ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
155 	if (!ii)
156 		return NULL;
157 	ii->i_bh = NULL;
158 	ii->i_state = 0;
159 	ii->vfs_inode.i_version = 1;
160 	nilfs_btnode_cache_init(&ii->i_btnode_cache, nilfs->ns_bdi);
161 	return &ii->vfs_inode;
162 }
163 
164 struct inode *nilfs_alloc_inode(struct super_block *sb)
165 {
166 	return nilfs_alloc_inode_common(NILFS_SB(sb)->s_nilfs);
167 }
168 
169 void nilfs_destroy_inode(struct inode *inode)
170 {
171 	kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
172 }
173 
174 static int nilfs_sync_super(struct nilfs_sb_info *sbi, int flag)
175 {
176 	struct the_nilfs *nilfs = sbi->s_nilfs;
177 	int err;
178 	int barrier_done = 0;
179 
180 	if (nilfs_test_opt(sbi, BARRIER)) {
181 		set_buffer_ordered(nilfs->ns_sbh[0]);
182 		barrier_done = 1;
183 	}
184  retry:
185 	set_buffer_dirty(nilfs->ns_sbh[0]);
186 	err = sync_dirty_buffer(nilfs->ns_sbh[0]);
187 	if (err == -EOPNOTSUPP && barrier_done) {
188 		nilfs_warning(sbi->s_super, __func__,
189 			      "barrier-based sync failed. "
190 			      "disabling barriers\n");
191 		nilfs_clear_opt(sbi, BARRIER);
192 		barrier_done = 0;
193 		clear_buffer_ordered(nilfs->ns_sbh[0]);
194 		goto retry;
195 	}
196 	if (unlikely(err)) {
197 		printk(KERN_ERR
198 		       "NILFS: unable to write superblock (err=%d)\n", err);
199 		if (err == -EIO && nilfs->ns_sbh[1]) {
200 			/*
201 			 * sbp[0] points to newer log than sbp[1],
202 			 * so copy sbp[0] to sbp[1] to take over sbp[0].
203 			 */
204 			memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
205 			       nilfs->ns_sbsize);
206 			nilfs_fall_back_super_block(nilfs);
207 			goto retry;
208 		}
209 	} else {
210 		struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
211 
212 		nilfs->ns_sbwcount++;
213 
214 		/*
215 		 * The latest segment becomes trailable from the position
216 		 * written in superblock.
217 		 */
218 		clear_nilfs_discontinued(nilfs);
219 
220 		/* update GC protection for recent segments */
221 		if (nilfs->ns_sbh[1]) {
222 			if (flag == NILFS_SB_COMMIT_ALL) {
223 				set_buffer_dirty(nilfs->ns_sbh[1]);
224 				if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
225 					goto out;
226 			}
227 			if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
228 			    le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
229 				sbp = nilfs->ns_sbp[1];
230 		}
231 
232 		spin_lock(&nilfs->ns_last_segment_lock);
233 		nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
234 		spin_unlock(&nilfs->ns_last_segment_lock);
235 	}
236  out:
237 	return err;
238 }
239 
240 void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
241 			  struct the_nilfs *nilfs)
242 {
243 	sector_t nfreeblocks;
244 
245 	/* nilfs->ns_sem must be locked by the caller. */
246 	nilfs_count_free_blocks(nilfs, &nfreeblocks);
247 	sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
248 
249 	spin_lock(&nilfs->ns_last_segment_lock);
250 	sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
251 	sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
252 	sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
253 	spin_unlock(&nilfs->ns_last_segment_lock);
254 }
255 
256 struct nilfs_super_block **nilfs_prepare_super(struct nilfs_sb_info *sbi,
257 					       int flip)
258 {
259 	struct the_nilfs *nilfs = sbi->s_nilfs;
260 	struct nilfs_super_block **sbp = nilfs->ns_sbp;
261 
262 	/* nilfs->ns_sem must be locked by the caller. */
263 	if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
264 		if (sbp[1] &&
265 		    sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
266 			memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
267 		} else {
268 			printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
269 			       sbi->s_super->s_id);
270 			return NULL;
271 		}
272 	} else if (sbp[1] &&
273 		   sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
274 			memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
275 	}
276 
277 	if (flip && sbp[1])
278 		nilfs_swap_super_block(nilfs);
279 
280 	return sbp;
281 }
282 
283 int nilfs_commit_super(struct nilfs_sb_info *sbi, int flag)
284 {
285 	struct the_nilfs *nilfs = sbi->s_nilfs;
286 	struct nilfs_super_block **sbp = nilfs->ns_sbp;
287 	time_t t;
288 
289 	/* nilfs->ns_sem must be locked by the caller. */
290 	t = get_seconds();
291 	nilfs->ns_sbwtime = t;
292 	sbp[0]->s_wtime = cpu_to_le64(t);
293 	sbp[0]->s_sum = 0;
294 	sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
295 					     (unsigned char *)sbp[0],
296 					     nilfs->ns_sbsize));
297 	if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
298 		sbp[1]->s_wtime = sbp[0]->s_wtime;
299 		sbp[1]->s_sum = 0;
300 		sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
301 					    (unsigned char *)sbp[1],
302 					    nilfs->ns_sbsize));
303 	}
304 	clear_nilfs_sb_dirty(nilfs);
305 	return nilfs_sync_super(sbi, flag);
306 }
307 
308 /**
309  * nilfs_cleanup_super() - write filesystem state for cleanup
310  * @sbi: nilfs_sb_info to be unmounted or degraded to read-only
311  *
312  * This function restores state flags in the on-disk super block.
313  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
314  * filesystem was not clean previously.
315  */
316 int nilfs_cleanup_super(struct nilfs_sb_info *sbi)
317 {
318 	struct nilfs_super_block **sbp;
319 	int flag = NILFS_SB_COMMIT;
320 	int ret = -EIO;
321 
322 	sbp = nilfs_prepare_super(sbi, 0);
323 	if (sbp) {
324 		sbp[0]->s_state = cpu_to_le16(sbi->s_nilfs->ns_mount_state);
325 		nilfs_set_log_cursor(sbp[0], sbi->s_nilfs);
326 		if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
327 			/*
328 			 * make the "clean" flag also to the opposite
329 			 * super block if both super blocks point to
330 			 * the same checkpoint.
331 			 */
332 			sbp[1]->s_state = sbp[0]->s_state;
333 			flag = NILFS_SB_COMMIT_ALL;
334 		}
335 		ret = nilfs_commit_super(sbi, flag);
336 	}
337 	return ret;
338 }
339 
340 static void nilfs_put_super(struct super_block *sb)
341 {
342 	struct nilfs_sb_info *sbi = NILFS_SB(sb);
343 	struct the_nilfs *nilfs = sbi->s_nilfs;
344 
345 	lock_kernel();
346 
347 	nilfs_detach_segment_constructor(sbi);
348 
349 	if (!(sb->s_flags & MS_RDONLY)) {
350 		down_write(&nilfs->ns_sem);
351 		nilfs_cleanup_super(sbi);
352 		up_write(&nilfs->ns_sem);
353 	}
354 	down_write(&nilfs->ns_super_sem);
355 	if (nilfs->ns_current == sbi)
356 		nilfs->ns_current = NULL;
357 	up_write(&nilfs->ns_super_sem);
358 
359 	nilfs_detach_checkpoint(sbi);
360 	put_nilfs(sbi->s_nilfs);
361 	sbi->s_super = NULL;
362 	sb->s_fs_info = NULL;
363 	nilfs_put_sbinfo(sbi);
364 
365 	unlock_kernel();
366 }
367 
368 static int nilfs_sync_fs(struct super_block *sb, int wait)
369 {
370 	struct nilfs_sb_info *sbi = NILFS_SB(sb);
371 	struct the_nilfs *nilfs = sbi->s_nilfs;
372 	struct nilfs_super_block **sbp;
373 	int err = 0;
374 
375 	/* This function is called when super block should be written back */
376 	if (wait)
377 		err = nilfs_construct_segment(sb);
378 
379 	down_write(&nilfs->ns_sem);
380 	if (nilfs_sb_dirty(nilfs)) {
381 		sbp = nilfs_prepare_super(sbi, nilfs_sb_will_flip(nilfs));
382 		if (likely(sbp)) {
383 			nilfs_set_log_cursor(sbp[0], nilfs);
384 			nilfs_commit_super(sbi, NILFS_SB_COMMIT);
385 		}
386 	}
387 	up_write(&nilfs->ns_sem);
388 
389 	return err;
390 }
391 
392 int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno)
393 {
394 	struct the_nilfs *nilfs = sbi->s_nilfs;
395 	struct nilfs_checkpoint *raw_cp;
396 	struct buffer_head *bh_cp;
397 	int err;
398 
399 	down_write(&nilfs->ns_super_sem);
400 	list_add(&sbi->s_list, &nilfs->ns_supers);
401 	up_write(&nilfs->ns_super_sem);
402 
403 	sbi->s_ifile = nilfs_ifile_new(sbi, nilfs->ns_inode_size);
404 	if (!sbi->s_ifile)
405 		return -ENOMEM;
406 
407 	down_read(&nilfs->ns_segctor_sem);
408 	err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
409 					  &bh_cp);
410 	up_read(&nilfs->ns_segctor_sem);
411 	if (unlikely(err)) {
412 		if (err == -ENOENT || err == -EINVAL) {
413 			printk(KERN_ERR
414 			       "NILFS: Invalid checkpoint "
415 			       "(checkpoint number=%llu)\n",
416 			       (unsigned long long)cno);
417 			err = -EINVAL;
418 		}
419 		goto failed;
420 	}
421 	err = nilfs_read_inode_common(sbi->s_ifile, &raw_cp->cp_ifile_inode);
422 	if (unlikely(err))
423 		goto failed_bh;
424 	atomic_set(&sbi->s_inodes_count, le64_to_cpu(raw_cp->cp_inodes_count));
425 	atomic_set(&sbi->s_blocks_count, le64_to_cpu(raw_cp->cp_blocks_count));
426 
427 	nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
428 	return 0;
429 
430  failed_bh:
431 	nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
432  failed:
433 	nilfs_mdt_destroy(sbi->s_ifile);
434 	sbi->s_ifile = NULL;
435 
436 	down_write(&nilfs->ns_super_sem);
437 	list_del_init(&sbi->s_list);
438 	up_write(&nilfs->ns_super_sem);
439 
440 	return err;
441 }
442 
443 void nilfs_detach_checkpoint(struct nilfs_sb_info *sbi)
444 {
445 	struct the_nilfs *nilfs = sbi->s_nilfs;
446 
447 	nilfs_mdt_destroy(sbi->s_ifile);
448 	sbi->s_ifile = NULL;
449 	down_write(&nilfs->ns_super_sem);
450 	list_del_init(&sbi->s_list);
451 	up_write(&nilfs->ns_super_sem);
452 }
453 
454 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
455 {
456 	struct super_block *sb = dentry->d_sb;
457 	struct nilfs_sb_info *sbi = NILFS_SB(sb);
458 	struct the_nilfs *nilfs = sbi->s_nilfs;
459 	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
460 	unsigned long long blocks;
461 	unsigned long overhead;
462 	unsigned long nrsvblocks;
463 	sector_t nfreeblocks;
464 	int err;
465 
466 	/*
467 	 * Compute all of the segment blocks
468 	 *
469 	 * The blocks before first segment and after last segment
470 	 * are excluded.
471 	 */
472 	blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
473 		- nilfs->ns_first_data_block;
474 	nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
475 
476 	/*
477 	 * Compute the overhead
478 	 *
479 	 * When distributing meta data blocks outside segment structure,
480 	 * We must count them as the overhead.
481 	 */
482 	overhead = 0;
483 
484 	err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
485 	if (unlikely(err))
486 		return err;
487 
488 	buf->f_type = NILFS_SUPER_MAGIC;
489 	buf->f_bsize = sb->s_blocksize;
490 	buf->f_blocks = blocks - overhead;
491 	buf->f_bfree = nfreeblocks;
492 	buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
493 		(buf->f_bfree - nrsvblocks) : 0;
494 	buf->f_files = atomic_read(&sbi->s_inodes_count);
495 	buf->f_ffree = 0; /* nilfs_count_free_inodes(sb); */
496 	buf->f_namelen = NILFS_NAME_LEN;
497 	buf->f_fsid.val[0] = (u32)id;
498 	buf->f_fsid.val[1] = (u32)(id >> 32);
499 
500 	return 0;
501 }
502 
503 static int nilfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
504 {
505 	struct super_block *sb = vfs->mnt_sb;
506 	struct nilfs_sb_info *sbi = NILFS_SB(sb);
507 
508 	if (!nilfs_test_opt(sbi, BARRIER))
509 		seq_puts(seq, ",nobarrier");
510 	if (nilfs_test_opt(sbi, SNAPSHOT))
511 		seq_printf(seq, ",cp=%llu",
512 			   (unsigned long long int)sbi->s_snapshot_cno);
513 	if (nilfs_test_opt(sbi, ERRORS_PANIC))
514 		seq_puts(seq, ",errors=panic");
515 	if (nilfs_test_opt(sbi, ERRORS_CONT))
516 		seq_puts(seq, ",errors=continue");
517 	if (nilfs_test_opt(sbi, STRICT_ORDER))
518 		seq_puts(seq, ",order=strict");
519 	if (nilfs_test_opt(sbi, NORECOVERY))
520 		seq_puts(seq, ",norecovery");
521 	if (nilfs_test_opt(sbi, DISCARD))
522 		seq_puts(seq, ",discard");
523 
524 	return 0;
525 }
526 
527 static const struct super_operations nilfs_sops = {
528 	.alloc_inode    = nilfs_alloc_inode,
529 	.destroy_inode  = nilfs_destroy_inode,
530 	.dirty_inode    = nilfs_dirty_inode,
531 	/* .write_inode    = nilfs_write_inode, */
532 	/* .put_inode      = nilfs_put_inode, */
533 	/* .drop_inode	  = nilfs_drop_inode, */
534 	.evict_inode    = nilfs_evict_inode,
535 	.put_super      = nilfs_put_super,
536 	/* .write_super    = nilfs_write_super, */
537 	.sync_fs        = nilfs_sync_fs,
538 	/* .write_super_lockfs */
539 	/* .unlockfs */
540 	.statfs         = nilfs_statfs,
541 	.remount_fs     = nilfs_remount,
542 	/* .umount_begin */
543 	.show_options = nilfs_show_options
544 };
545 
546 static struct inode *
547 nilfs_nfs_get_inode(struct super_block *sb, u64 ino, u32 generation)
548 {
549 	struct inode *inode;
550 
551 	if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO &&
552 	    ino != NILFS_SKETCH_INO)
553 		return ERR_PTR(-ESTALE);
554 
555 	inode = nilfs_iget(sb, ino);
556 	if (IS_ERR(inode))
557 		return ERR_CAST(inode);
558 	if (generation && inode->i_generation != generation) {
559 		iput(inode);
560 		return ERR_PTR(-ESTALE);
561 	}
562 
563 	return inode;
564 }
565 
566 static struct dentry *
567 nilfs_fh_to_dentry(struct super_block *sb, struct fid *fid, int fh_len,
568 		   int fh_type)
569 {
570 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
571 				    nilfs_nfs_get_inode);
572 }
573 
574 static struct dentry *
575 nilfs_fh_to_parent(struct super_block *sb, struct fid *fid, int fh_len,
576 		   int fh_type)
577 {
578 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
579 				    nilfs_nfs_get_inode);
580 }
581 
582 static const struct export_operations nilfs_export_ops = {
583 	.fh_to_dentry = nilfs_fh_to_dentry,
584 	.fh_to_parent = nilfs_fh_to_parent,
585 	.get_parent = nilfs_get_parent,
586 };
587 
588 enum {
589 	Opt_err_cont, Opt_err_panic, Opt_err_ro,
590 	Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
591 	Opt_discard, Opt_nodiscard, Opt_err,
592 };
593 
594 static match_table_t tokens = {
595 	{Opt_err_cont, "errors=continue"},
596 	{Opt_err_panic, "errors=panic"},
597 	{Opt_err_ro, "errors=remount-ro"},
598 	{Opt_barrier, "barrier"},
599 	{Opt_nobarrier, "nobarrier"},
600 	{Opt_snapshot, "cp=%u"},
601 	{Opt_order, "order=%s"},
602 	{Opt_norecovery, "norecovery"},
603 	{Opt_discard, "discard"},
604 	{Opt_nodiscard, "nodiscard"},
605 	{Opt_err, NULL}
606 };
607 
608 static int parse_options(char *options, struct super_block *sb, int is_remount)
609 {
610 	struct nilfs_sb_info *sbi = NILFS_SB(sb);
611 	char *p;
612 	substring_t args[MAX_OPT_ARGS];
613 	int option;
614 
615 	if (!options)
616 		return 1;
617 
618 	while ((p = strsep(&options, ",")) != NULL) {
619 		int token;
620 		if (!*p)
621 			continue;
622 
623 		token = match_token(p, tokens, args);
624 		switch (token) {
625 		case Opt_barrier:
626 			nilfs_set_opt(sbi, BARRIER);
627 			break;
628 		case Opt_nobarrier:
629 			nilfs_clear_opt(sbi, BARRIER);
630 			break;
631 		case Opt_order:
632 			if (strcmp(args[0].from, "relaxed") == 0)
633 				/* Ordered data semantics */
634 				nilfs_clear_opt(sbi, STRICT_ORDER);
635 			else if (strcmp(args[0].from, "strict") == 0)
636 				/* Strict in-order semantics */
637 				nilfs_set_opt(sbi, STRICT_ORDER);
638 			else
639 				return 0;
640 			break;
641 		case Opt_err_panic:
642 			nilfs_write_opt(sbi, ERROR_MODE, ERRORS_PANIC);
643 			break;
644 		case Opt_err_ro:
645 			nilfs_write_opt(sbi, ERROR_MODE, ERRORS_RO);
646 			break;
647 		case Opt_err_cont:
648 			nilfs_write_opt(sbi, ERROR_MODE, ERRORS_CONT);
649 			break;
650 		case Opt_snapshot:
651 			if (match_int(&args[0], &option) || option <= 0)
652 				return 0;
653 			if (is_remount) {
654 				if (!nilfs_test_opt(sbi, SNAPSHOT)) {
655 					printk(KERN_ERR
656 					       "NILFS: cannot change regular "
657 					       "mount to snapshot.\n");
658 					return 0;
659 				} else if (option != sbi->s_snapshot_cno) {
660 					printk(KERN_ERR
661 					       "NILFS: cannot remount to a "
662 					       "different snapshot.\n");
663 					return 0;
664 				}
665 				break;
666 			}
667 			if (!(sb->s_flags & MS_RDONLY)) {
668 				printk(KERN_ERR "NILFS: cannot mount snapshot "
669 				       "read/write.  A read-only option is "
670 				       "required.\n");
671 				return 0;
672 			}
673 			sbi->s_snapshot_cno = option;
674 			nilfs_set_opt(sbi, SNAPSHOT);
675 			break;
676 		case Opt_norecovery:
677 			nilfs_set_opt(sbi, NORECOVERY);
678 			break;
679 		case Opt_discard:
680 			nilfs_set_opt(sbi, DISCARD);
681 			break;
682 		case Opt_nodiscard:
683 			nilfs_clear_opt(sbi, DISCARD);
684 			break;
685 		default:
686 			printk(KERN_ERR
687 			       "NILFS: Unrecognized mount option \"%s\"\n", p);
688 			return 0;
689 		}
690 	}
691 	return 1;
692 }
693 
694 static inline void
695 nilfs_set_default_options(struct nilfs_sb_info *sbi,
696 			  struct nilfs_super_block *sbp)
697 {
698 	sbi->s_mount_opt =
699 		NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
700 }
701 
702 static int nilfs_setup_super(struct nilfs_sb_info *sbi)
703 {
704 	struct the_nilfs *nilfs = sbi->s_nilfs;
705 	struct nilfs_super_block **sbp;
706 	int max_mnt_count;
707 	int mnt_count;
708 
709 	/* nilfs->ns_sem must be locked by the caller. */
710 	sbp = nilfs_prepare_super(sbi, 0);
711 	if (!sbp)
712 		return -EIO;
713 
714 	max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
715 	mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
716 
717 	if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
718 		printk(KERN_WARNING
719 		       "NILFS warning: mounting fs with errors\n");
720 #if 0
721 	} else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
722 		printk(KERN_WARNING
723 		       "NILFS warning: maximal mount count reached\n");
724 #endif
725 	}
726 	if (!max_mnt_count)
727 		sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
728 
729 	sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
730 	sbp[0]->s_state =
731 		cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
732 	sbp[0]->s_mtime = cpu_to_le64(get_seconds());
733 	/* synchronize sbp[1] with sbp[0] */
734 	memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
735 	return nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
736 }
737 
738 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
739 						 u64 pos, int blocksize,
740 						 struct buffer_head **pbh)
741 {
742 	unsigned long long sb_index = pos;
743 	unsigned long offset;
744 
745 	offset = do_div(sb_index, blocksize);
746 	*pbh = sb_bread(sb, sb_index);
747 	if (!*pbh)
748 		return NULL;
749 	return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
750 }
751 
752 int nilfs_store_magic_and_option(struct super_block *sb,
753 				 struct nilfs_super_block *sbp,
754 				 char *data)
755 {
756 	struct nilfs_sb_info *sbi = NILFS_SB(sb);
757 
758 	sb->s_magic = le16_to_cpu(sbp->s_magic);
759 
760 	/* FS independent flags */
761 #ifdef NILFS_ATIME_DISABLE
762 	sb->s_flags |= MS_NOATIME;
763 #endif
764 
765 	nilfs_set_default_options(sbi, sbp);
766 
767 	sbi->s_resuid = le16_to_cpu(sbp->s_def_resuid);
768 	sbi->s_resgid = le16_to_cpu(sbp->s_def_resgid);
769 	sbi->s_interval = le32_to_cpu(sbp->s_c_interval);
770 	sbi->s_watermark = le32_to_cpu(sbp->s_c_block_max);
771 
772 	return !parse_options(data, sb, 0) ? -EINVAL : 0 ;
773 }
774 
775 int nilfs_check_feature_compatibility(struct super_block *sb,
776 				      struct nilfs_super_block *sbp)
777 {
778 	__u64 features;
779 
780 	features = le64_to_cpu(sbp->s_feature_incompat) &
781 		~NILFS_FEATURE_INCOMPAT_SUPP;
782 	if (features) {
783 		printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
784 		       "optional features (%llx)\n",
785 		       (unsigned long long)features);
786 		return -EINVAL;
787 	}
788 	features = le64_to_cpu(sbp->s_feature_compat_ro) &
789 		~NILFS_FEATURE_COMPAT_RO_SUPP;
790 	if (!(sb->s_flags & MS_RDONLY) && features) {
791 		printk(KERN_ERR "NILFS: couldn't mount RDWR because of "
792 		       "unsupported optional features (%llx)\n",
793 		       (unsigned long long)features);
794 		return -EINVAL;
795 	}
796 	return 0;
797 }
798 
799 /**
800  * nilfs_fill_super() - initialize a super block instance
801  * @sb: super_block
802  * @data: mount options
803  * @silent: silent mode flag
804  * @nilfs: the_nilfs struct
805  *
806  * This function is called exclusively by nilfs->ns_mount_mutex.
807  * So, the recovery process is protected from other simultaneous mounts.
808  */
809 static int
810 nilfs_fill_super(struct super_block *sb, void *data, int silent,
811 		 struct the_nilfs *nilfs)
812 {
813 	struct nilfs_sb_info *sbi;
814 	struct inode *root;
815 	__u64 cno;
816 	int err;
817 
818 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
819 	if (!sbi)
820 		return -ENOMEM;
821 
822 	sb->s_fs_info = sbi;
823 
824 	get_nilfs(nilfs);
825 	sbi->s_nilfs = nilfs;
826 	sbi->s_super = sb;
827 	atomic_set(&sbi->s_count, 1);
828 
829 	err = init_nilfs(nilfs, sbi, (char *)data);
830 	if (err)
831 		goto failed_sbi;
832 
833 	spin_lock_init(&sbi->s_inode_lock);
834 	INIT_LIST_HEAD(&sbi->s_dirty_files);
835 	INIT_LIST_HEAD(&sbi->s_list);
836 
837 	/*
838 	 * Following initialization is overlapped because
839 	 * nilfs_sb_info structure has been cleared at the beginning.
840 	 * But we reserve them to keep our interest and make ready
841 	 * for the future change.
842 	 */
843 	get_random_bytes(&sbi->s_next_generation,
844 			 sizeof(sbi->s_next_generation));
845 	spin_lock_init(&sbi->s_next_gen_lock);
846 
847 	sb->s_op = &nilfs_sops;
848 	sb->s_export_op = &nilfs_export_ops;
849 	sb->s_root = NULL;
850 	sb->s_time_gran = 1;
851 	sb->s_bdi = nilfs->ns_bdi;
852 
853 	err = load_nilfs(nilfs, sbi);
854 	if (err)
855 		goto failed_sbi;
856 
857 	cno = nilfs_last_cno(nilfs);
858 
859 	if (sb->s_flags & MS_RDONLY) {
860 		if (nilfs_test_opt(sbi, SNAPSHOT)) {
861 			down_read(&nilfs->ns_segctor_sem);
862 			err = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile,
863 						       sbi->s_snapshot_cno);
864 			up_read(&nilfs->ns_segctor_sem);
865 			if (err < 0) {
866 				if (err == -ENOENT)
867 					err = -EINVAL;
868 				goto failed_sbi;
869 			}
870 			if (!err) {
871 				printk(KERN_ERR
872 				       "NILFS: The specified checkpoint is "
873 				       "not a snapshot "
874 				       "(checkpoint number=%llu).\n",
875 				       (unsigned long long)sbi->s_snapshot_cno);
876 				err = -EINVAL;
877 				goto failed_sbi;
878 			}
879 			cno = sbi->s_snapshot_cno;
880 		}
881 	}
882 
883 	err = nilfs_attach_checkpoint(sbi, cno);
884 	if (err) {
885 		printk(KERN_ERR "NILFS: error loading a checkpoint"
886 		       " (checkpoint number=%llu).\n", (unsigned long long)cno);
887 		goto failed_sbi;
888 	}
889 
890 	if (!(sb->s_flags & MS_RDONLY)) {
891 		err = nilfs_attach_segment_constructor(sbi);
892 		if (err)
893 			goto failed_checkpoint;
894 	}
895 
896 	root = nilfs_iget(sb, NILFS_ROOT_INO);
897 	if (IS_ERR(root)) {
898 		printk(KERN_ERR "NILFS: get root inode failed\n");
899 		err = PTR_ERR(root);
900 		goto failed_segctor;
901 	}
902 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
903 		iput(root);
904 		printk(KERN_ERR "NILFS: corrupt root inode.\n");
905 		err = -EINVAL;
906 		goto failed_segctor;
907 	}
908 	sb->s_root = d_alloc_root(root);
909 	if (!sb->s_root) {
910 		iput(root);
911 		printk(KERN_ERR "NILFS: get root dentry failed\n");
912 		err = -ENOMEM;
913 		goto failed_segctor;
914 	}
915 
916 	if (!(sb->s_flags & MS_RDONLY)) {
917 		down_write(&nilfs->ns_sem);
918 		nilfs_setup_super(sbi);
919 		up_write(&nilfs->ns_sem);
920 	}
921 
922 	down_write(&nilfs->ns_super_sem);
923 	if (!nilfs_test_opt(sbi, SNAPSHOT))
924 		nilfs->ns_current = sbi;
925 	up_write(&nilfs->ns_super_sem);
926 
927 	return 0;
928 
929  failed_segctor:
930 	nilfs_detach_segment_constructor(sbi);
931 
932  failed_checkpoint:
933 	nilfs_detach_checkpoint(sbi);
934 
935  failed_sbi:
936 	put_nilfs(nilfs);
937 	sb->s_fs_info = NULL;
938 	nilfs_put_sbinfo(sbi);
939 	return err;
940 }
941 
942 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
943 {
944 	struct nilfs_sb_info *sbi = NILFS_SB(sb);
945 	struct the_nilfs *nilfs = sbi->s_nilfs;
946 	unsigned long old_sb_flags;
947 	struct nilfs_mount_options old_opts;
948 	int was_snapshot, err;
949 
950 	lock_kernel();
951 
952 	down_write(&nilfs->ns_super_sem);
953 	old_sb_flags = sb->s_flags;
954 	old_opts.mount_opt = sbi->s_mount_opt;
955 	old_opts.snapshot_cno = sbi->s_snapshot_cno;
956 	was_snapshot = nilfs_test_opt(sbi, SNAPSHOT);
957 
958 	if (!parse_options(data, sb, 1)) {
959 		err = -EINVAL;
960 		goto restore_opts;
961 	}
962 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
963 
964 	err = -EINVAL;
965 	if (was_snapshot && !(*flags & MS_RDONLY)) {
966 		printk(KERN_ERR "NILFS (device %s): cannot remount snapshot "
967 		       "read/write.\n", sb->s_id);
968 		goto restore_opts;
969 	}
970 
971 	if (!nilfs_valid_fs(nilfs)) {
972 		printk(KERN_WARNING "NILFS (device %s): couldn't "
973 		       "remount because the filesystem is in an "
974 		       "incomplete recovery state.\n", sb->s_id);
975 		goto restore_opts;
976 	}
977 
978 	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
979 		goto out;
980 	if (*flags & MS_RDONLY) {
981 		/* Shutting down the segment constructor */
982 		nilfs_detach_segment_constructor(sbi);
983 		sb->s_flags |= MS_RDONLY;
984 
985 		/*
986 		 * Remounting a valid RW partition RDONLY, so set
987 		 * the RDONLY flag and then mark the partition as valid again.
988 		 */
989 		down_write(&nilfs->ns_sem);
990 		nilfs_cleanup_super(sbi);
991 		up_write(&nilfs->ns_sem);
992 	} else {
993 		__u64 features;
994 
995 		/*
996 		 * Mounting a RDONLY partition read-write, so reread and
997 		 * store the current valid flag.  (It may have been changed
998 		 * by fsck since we originally mounted the partition.)
999 		 */
1000 		down_read(&nilfs->ns_sem);
1001 		features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1002 			~NILFS_FEATURE_COMPAT_RO_SUPP;
1003 		up_read(&nilfs->ns_sem);
1004 		if (features) {
1005 			printk(KERN_WARNING "NILFS (device %s): couldn't "
1006 			       "remount RDWR because of unsupported optional "
1007 			       "features (%llx)\n",
1008 			       sb->s_id, (unsigned long long)features);
1009 			err = -EROFS;
1010 			goto restore_opts;
1011 		}
1012 
1013 		sb->s_flags &= ~MS_RDONLY;
1014 
1015 		err = nilfs_attach_segment_constructor(sbi);
1016 		if (err)
1017 			goto restore_opts;
1018 
1019 		down_write(&nilfs->ns_sem);
1020 		nilfs_setup_super(sbi);
1021 		up_write(&nilfs->ns_sem);
1022 	}
1023  out:
1024 	up_write(&nilfs->ns_super_sem);
1025 	unlock_kernel();
1026 	return 0;
1027 
1028  restore_opts:
1029 	sb->s_flags = old_sb_flags;
1030 	sbi->s_mount_opt = old_opts.mount_opt;
1031 	sbi->s_snapshot_cno = old_opts.snapshot_cno;
1032 	up_write(&nilfs->ns_super_sem);
1033 	unlock_kernel();
1034 	return err;
1035 }
1036 
1037 struct nilfs_super_data {
1038 	struct block_device *bdev;
1039 	struct nilfs_sb_info *sbi;
1040 	__u64 cno;
1041 	int flags;
1042 };
1043 
1044 /**
1045  * nilfs_identify - pre-read mount options needed to identify mount instance
1046  * @data: mount options
1047  * @sd: nilfs_super_data
1048  */
1049 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1050 {
1051 	char *p, *options = data;
1052 	substring_t args[MAX_OPT_ARGS];
1053 	int option, token;
1054 	int ret = 0;
1055 
1056 	do {
1057 		p = strsep(&options, ",");
1058 		if (p != NULL && *p) {
1059 			token = match_token(p, tokens, args);
1060 			if (token == Opt_snapshot) {
1061 				if (!(sd->flags & MS_RDONLY))
1062 					ret++;
1063 				else {
1064 					ret = match_int(&args[0], &option);
1065 					if (!ret) {
1066 						if (option > 0)
1067 							sd->cno = option;
1068 						else
1069 							ret++;
1070 					}
1071 				}
1072 			}
1073 			if (ret)
1074 				printk(KERN_ERR
1075 				       "NILFS: invalid mount option: %s\n", p);
1076 		}
1077 		if (!options)
1078 			break;
1079 		BUG_ON(options == data);
1080 		*(options - 1) = ',';
1081 	} while (!ret);
1082 	return ret;
1083 }
1084 
1085 static int nilfs_set_bdev_super(struct super_block *s, void *data)
1086 {
1087 	struct nilfs_super_data *sd = data;
1088 
1089 	s->s_bdev = sd->bdev;
1090 	s->s_dev = s->s_bdev->bd_dev;
1091 	return 0;
1092 }
1093 
1094 static int nilfs_test_bdev_super(struct super_block *s, void *data)
1095 {
1096 	struct nilfs_super_data *sd = data;
1097 
1098 	return sd->sbi && s->s_fs_info == (void *)sd->sbi;
1099 }
1100 
1101 static int
1102 nilfs_get_sb(struct file_system_type *fs_type, int flags,
1103 	     const char *dev_name, void *data, struct vfsmount *mnt)
1104 {
1105 	struct nilfs_super_data sd;
1106 	struct super_block *s;
1107 	fmode_t mode = FMODE_READ;
1108 	struct the_nilfs *nilfs;
1109 	int err, need_to_close = 1;
1110 
1111 	if (!(flags & MS_RDONLY))
1112 		mode |= FMODE_WRITE;
1113 
1114 	sd.bdev = open_bdev_exclusive(dev_name, mode, fs_type);
1115 	if (IS_ERR(sd.bdev))
1116 		return PTR_ERR(sd.bdev);
1117 
1118 	/*
1119 	 * To get mount instance using sget() vfs-routine, NILFS needs
1120 	 * much more information than normal filesystems to identify mount
1121 	 * instance.  For snapshot mounts, not only a mount type (ro-mount
1122 	 * or rw-mount) but also a checkpoint number is required.
1123 	 */
1124 	sd.cno = 0;
1125 	sd.flags = flags;
1126 	if (nilfs_identify((char *)data, &sd)) {
1127 		err = -EINVAL;
1128 		goto failed;
1129 	}
1130 
1131 	nilfs = find_or_create_nilfs(sd.bdev);
1132 	if (!nilfs) {
1133 		err = -ENOMEM;
1134 		goto failed;
1135 	}
1136 
1137 	mutex_lock(&nilfs->ns_mount_mutex);
1138 
1139 	if (!sd.cno) {
1140 		/*
1141 		 * Check if an exclusive mount exists or not.
1142 		 * Snapshot mounts coexist with a current mount
1143 		 * (i.e. rw-mount or ro-mount), whereas rw-mount and
1144 		 * ro-mount are mutually exclusive.
1145 		 */
1146 		down_read(&nilfs->ns_super_sem);
1147 		if (nilfs->ns_current &&
1148 		    ((nilfs->ns_current->s_super->s_flags ^ flags)
1149 		     & MS_RDONLY)) {
1150 			up_read(&nilfs->ns_super_sem);
1151 			err = -EBUSY;
1152 			goto failed_unlock;
1153 		}
1154 		up_read(&nilfs->ns_super_sem);
1155 	}
1156 
1157 	/*
1158 	 * Find existing nilfs_sb_info struct
1159 	 */
1160 	sd.sbi = nilfs_find_sbinfo(nilfs, !(flags & MS_RDONLY), sd.cno);
1161 
1162 	/*
1163 	 * Get super block instance holding the nilfs_sb_info struct.
1164 	 * A new instance is allocated if no existing mount is present or
1165 	 * existing instance has been unmounted.
1166 	 */
1167 	s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, &sd);
1168 	if (sd.sbi)
1169 		nilfs_put_sbinfo(sd.sbi);
1170 
1171 	if (IS_ERR(s)) {
1172 		err = PTR_ERR(s);
1173 		goto failed_unlock;
1174 	}
1175 
1176 	if (!s->s_root) {
1177 		char b[BDEVNAME_SIZE];
1178 
1179 		/* New superblock instance created */
1180 		s->s_flags = flags;
1181 		s->s_mode = mode;
1182 		strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
1183 		sb_set_blocksize(s, block_size(sd.bdev));
1184 
1185 		err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0,
1186 				       nilfs);
1187 		if (err)
1188 			goto cancel_new;
1189 
1190 		s->s_flags |= MS_ACTIVE;
1191 		need_to_close = 0;
1192 	}
1193 
1194 	mutex_unlock(&nilfs->ns_mount_mutex);
1195 	put_nilfs(nilfs);
1196 	if (need_to_close)
1197 		close_bdev_exclusive(sd.bdev, mode);
1198 	simple_set_mnt(mnt, s);
1199 	return 0;
1200 
1201  failed_unlock:
1202 	mutex_unlock(&nilfs->ns_mount_mutex);
1203 	put_nilfs(nilfs);
1204  failed:
1205 	close_bdev_exclusive(sd.bdev, mode);
1206 
1207 	return err;
1208 
1209  cancel_new:
1210 	/* Abandoning the newly allocated superblock */
1211 	mutex_unlock(&nilfs->ns_mount_mutex);
1212 	put_nilfs(nilfs);
1213 	deactivate_locked_super(s);
1214 	/*
1215 	 * deactivate_locked_super() invokes close_bdev_exclusive().
1216 	 * We must finish all post-cleaning before this call;
1217 	 * put_nilfs() needs the block device.
1218 	 */
1219 	return err;
1220 }
1221 
1222 struct file_system_type nilfs_fs_type = {
1223 	.owner    = THIS_MODULE,
1224 	.name     = "nilfs2",
1225 	.get_sb   = nilfs_get_sb,
1226 	.kill_sb  = kill_block_super,
1227 	.fs_flags = FS_REQUIRES_DEV,
1228 };
1229 
1230 static void nilfs_inode_init_once(void *obj)
1231 {
1232 	struct nilfs_inode_info *ii = obj;
1233 
1234 	INIT_LIST_HEAD(&ii->i_dirty);
1235 #ifdef CONFIG_NILFS_XATTR
1236 	init_rwsem(&ii->xattr_sem);
1237 #endif
1238 	nilfs_btnode_cache_init_once(&ii->i_btnode_cache);
1239 	ii->i_bmap = &ii->i_bmap_data;
1240 	inode_init_once(&ii->vfs_inode);
1241 }
1242 
1243 static void nilfs_segbuf_init_once(void *obj)
1244 {
1245 	memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1246 }
1247 
1248 static void nilfs_destroy_cachep(void)
1249 {
1250 	if (nilfs_inode_cachep)
1251 		kmem_cache_destroy(nilfs_inode_cachep);
1252 	if (nilfs_transaction_cachep)
1253 		kmem_cache_destroy(nilfs_transaction_cachep);
1254 	if (nilfs_segbuf_cachep)
1255 		kmem_cache_destroy(nilfs_segbuf_cachep);
1256 	if (nilfs_btree_path_cache)
1257 		kmem_cache_destroy(nilfs_btree_path_cache);
1258 }
1259 
1260 static int __init nilfs_init_cachep(void)
1261 {
1262 	nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1263 			sizeof(struct nilfs_inode_info), 0,
1264 			SLAB_RECLAIM_ACCOUNT, nilfs_inode_init_once);
1265 	if (!nilfs_inode_cachep)
1266 		goto fail;
1267 
1268 	nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1269 			sizeof(struct nilfs_transaction_info), 0,
1270 			SLAB_RECLAIM_ACCOUNT, NULL);
1271 	if (!nilfs_transaction_cachep)
1272 		goto fail;
1273 
1274 	nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1275 			sizeof(struct nilfs_segment_buffer), 0,
1276 			SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1277 	if (!nilfs_segbuf_cachep)
1278 		goto fail;
1279 
1280 	nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1281 			sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1282 			0, 0, NULL);
1283 	if (!nilfs_btree_path_cache)
1284 		goto fail;
1285 
1286 	return 0;
1287 
1288 fail:
1289 	nilfs_destroy_cachep();
1290 	return -ENOMEM;
1291 }
1292 
1293 static int __init init_nilfs_fs(void)
1294 {
1295 	int err;
1296 
1297 	err = nilfs_init_cachep();
1298 	if (err)
1299 		goto fail;
1300 
1301 	err = register_filesystem(&nilfs_fs_type);
1302 	if (err)
1303 		goto free_cachep;
1304 
1305 	printk(KERN_INFO "NILFS version 2 loaded\n");
1306 	return 0;
1307 
1308 free_cachep:
1309 	nilfs_destroy_cachep();
1310 fail:
1311 	return err;
1312 }
1313 
1314 static void __exit exit_nilfs_fs(void)
1315 {
1316 	nilfs_destroy_cachep();
1317 	unregister_filesystem(&nilfs_fs_type);
1318 }
1319 
1320 module_init(init_nilfs_fs)
1321 module_exit(exit_nilfs_fs)
1322