xref: /linux/fs/nilfs2/super.c (revision 92815da4576a495cb6362cdfb132152fccc2222d)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * NILFS module and super block management.
4  *
5  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6  *
7  * Written by Ryusuke Konishi.
8  */
9 /*
10  *  linux/fs/ext2/super.c
11  *
12  * Copyright (C) 1992, 1993, 1994, 1995
13  * Remy Card (card@masi.ibp.fr)
14  * Laboratoire MASI - Institut Blaise Pascal
15  * Universite Pierre et Marie Curie (Paris VI)
16  *
17  *  from
18  *
19  *  linux/fs/minix/inode.c
20  *
21  *  Copyright (C) 1991, 1992  Linus Torvalds
22  *
23  *  Big-endian to little-endian byte-swapping/bitmaps by
24  *        David S. Miller (davem@caip.rutgers.edu), 1995
25  */
26 
27 #include <linux/module.h>
28 #include <linux/string.h>
29 #include <linux/slab.h>
30 #include <linux/init.h>
31 #include <linux/blkdev.h>
32 #include <linux/crc32.h>
33 #include <linux/vfs.h>
34 #include <linux/writeback.h>
35 #include <linux/seq_file.h>
36 #include <linux/mount.h>
37 #include <linux/fs_context.h>
38 #include <linux/fs_parser.h>
39 #include "nilfs.h"
40 #include "export.h"
41 #include "mdt.h"
42 #include "alloc.h"
43 #include "btree.h"
44 #include "btnode.h"
45 #include "page.h"
46 #include "cpfile.h"
47 #include "sufile.h" /* nilfs_sufile_resize(), nilfs_sufile_set_alloc_range() */
48 #include "ifile.h"
49 #include "dat.h"
50 #include "segment.h"
51 #include "segbuf.h"
52 
53 MODULE_AUTHOR("NTT Corp.");
54 MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
55 		   "(NILFS)");
56 MODULE_LICENSE("GPL");
57 
58 static struct kmem_cache *nilfs_inode_cachep;
59 struct kmem_cache *nilfs_transaction_cachep;
60 struct kmem_cache *nilfs_segbuf_cachep;
61 struct kmem_cache *nilfs_btree_path_cache;
62 
63 static int nilfs_setup_super(struct super_block *sb, int is_mount);
64 
65 void __nilfs_msg(struct super_block *sb, const char *fmt, ...)
66 {
67 	struct va_format vaf;
68 	va_list args;
69 	int level;
70 
71 	va_start(args, fmt);
72 
73 	level = printk_get_level(fmt);
74 	vaf.fmt = printk_skip_level(fmt);
75 	vaf.va = &args;
76 
77 	if (sb)
78 		printk("%c%cNILFS (%s): %pV\n",
79 		       KERN_SOH_ASCII, level, sb->s_id, &vaf);
80 	else
81 		printk("%c%cNILFS: %pV\n",
82 		       KERN_SOH_ASCII, level, &vaf);
83 
84 	va_end(args);
85 }
86 
87 static void nilfs_set_error(struct super_block *sb)
88 {
89 	struct the_nilfs *nilfs = sb->s_fs_info;
90 	struct nilfs_super_block **sbp;
91 
92 	down_write(&nilfs->ns_sem);
93 	if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
94 		nilfs->ns_mount_state |= NILFS_ERROR_FS;
95 		sbp = nilfs_prepare_super(sb, 0);
96 		if (likely(sbp)) {
97 			sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
98 			if (sbp[1])
99 				sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
100 			nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
101 		}
102 	}
103 	up_write(&nilfs->ns_sem);
104 }
105 
106 /**
107  * __nilfs_error() - report failure condition on a filesystem
108  *
109  * __nilfs_error() sets an ERROR_FS flag on the superblock as well as
110  * reporting an error message.  This function should be called when
111  * NILFS detects incoherences or defects of meta data on disk.
112  *
113  * This implements the body of nilfs_error() macro.  Normally,
114  * nilfs_error() should be used.  As for sustainable errors such as a
115  * single-shot I/O error, nilfs_err() should be used instead.
116  *
117  * Callers should not add a trailing newline since this will do it.
118  */
119 void __nilfs_error(struct super_block *sb, const char *function,
120 		   const char *fmt, ...)
121 {
122 	struct the_nilfs *nilfs = sb->s_fs_info;
123 	struct va_format vaf;
124 	va_list args;
125 
126 	va_start(args, fmt);
127 
128 	vaf.fmt = fmt;
129 	vaf.va = &args;
130 
131 	printk(KERN_CRIT "NILFS error (device %s): %s: %pV\n",
132 	       sb->s_id, function, &vaf);
133 
134 	va_end(args);
135 
136 	if (!sb_rdonly(sb)) {
137 		nilfs_set_error(sb);
138 
139 		if (nilfs_test_opt(nilfs, ERRORS_RO)) {
140 			printk(KERN_CRIT "Remounting filesystem read-only\n");
141 			sb->s_flags |= SB_RDONLY;
142 		}
143 	}
144 
145 	if (nilfs_test_opt(nilfs, ERRORS_PANIC))
146 		panic("NILFS (device %s): panic forced after error\n",
147 		      sb->s_id);
148 }
149 
150 struct inode *nilfs_alloc_inode(struct super_block *sb)
151 {
152 	struct nilfs_inode_info *ii;
153 
154 	ii = alloc_inode_sb(sb, nilfs_inode_cachep, GFP_NOFS);
155 	if (!ii)
156 		return NULL;
157 	ii->i_bh = NULL;
158 	ii->i_state = 0;
159 	ii->i_cno = 0;
160 	ii->i_assoc_inode = NULL;
161 	ii->i_bmap = &ii->i_bmap_data;
162 	return &ii->vfs_inode;
163 }
164 
165 static void nilfs_free_inode(struct inode *inode)
166 {
167 	if (nilfs_is_metadata_file_inode(inode))
168 		nilfs_mdt_destroy(inode);
169 
170 	kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
171 }
172 
173 static int nilfs_sync_super(struct super_block *sb, int flag)
174 {
175 	struct the_nilfs *nilfs = sb->s_fs_info;
176 	int err;
177 
178  retry:
179 	set_buffer_dirty(nilfs->ns_sbh[0]);
180 	if (nilfs_test_opt(nilfs, BARRIER)) {
181 		err = __sync_dirty_buffer(nilfs->ns_sbh[0],
182 					  REQ_SYNC | REQ_PREFLUSH | REQ_FUA);
183 	} else {
184 		err = sync_dirty_buffer(nilfs->ns_sbh[0]);
185 	}
186 
187 	if (unlikely(err)) {
188 		nilfs_err(sb, "unable to write superblock: err=%d", err);
189 		if (err == -EIO && nilfs->ns_sbh[1]) {
190 			/*
191 			 * sbp[0] points to newer log than sbp[1],
192 			 * so copy sbp[0] to sbp[1] to take over sbp[0].
193 			 */
194 			memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
195 			       nilfs->ns_sbsize);
196 			nilfs_fall_back_super_block(nilfs);
197 			goto retry;
198 		}
199 	} else {
200 		struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
201 
202 		nilfs->ns_sbwcount++;
203 
204 		/*
205 		 * The latest segment becomes trailable from the position
206 		 * written in superblock.
207 		 */
208 		clear_nilfs_discontinued(nilfs);
209 
210 		/* update GC protection for recent segments */
211 		if (nilfs->ns_sbh[1]) {
212 			if (flag == NILFS_SB_COMMIT_ALL) {
213 				set_buffer_dirty(nilfs->ns_sbh[1]);
214 				if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
215 					goto out;
216 			}
217 			if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
218 			    le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
219 				sbp = nilfs->ns_sbp[1];
220 		}
221 
222 		spin_lock(&nilfs->ns_last_segment_lock);
223 		nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
224 		spin_unlock(&nilfs->ns_last_segment_lock);
225 	}
226  out:
227 	return err;
228 }
229 
230 void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
231 			  struct the_nilfs *nilfs)
232 {
233 	sector_t nfreeblocks;
234 
235 	/* nilfs->ns_sem must be locked by the caller. */
236 	nilfs_count_free_blocks(nilfs, &nfreeblocks);
237 	sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
238 
239 	spin_lock(&nilfs->ns_last_segment_lock);
240 	sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
241 	sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
242 	sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
243 	spin_unlock(&nilfs->ns_last_segment_lock);
244 }
245 
246 struct nilfs_super_block **nilfs_prepare_super(struct super_block *sb,
247 					       int flip)
248 {
249 	struct the_nilfs *nilfs = sb->s_fs_info;
250 	struct nilfs_super_block **sbp = nilfs->ns_sbp;
251 
252 	/* nilfs->ns_sem must be locked by the caller. */
253 	if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
254 		if (sbp[1] &&
255 		    sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
256 			memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
257 		} else {
258 			nilfs_crit(sb, "superblock broke");
259 			return NULL;
260 		}
261 	} else if (sbp[1] &&
262 		   sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
263 		memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
264 	}
265 
266 	if (flip && sbp[1])
267 		nilfs_swap_super_block(nilfs);
268 
269 	return sbp;
270 }
271 
272 int nilfs_commit_super(struct super_block *sb, int flag)
273 {
274 	struct the_nilfs *nilfs = sb->s_fs_info;
275 	struct nilfs_super_block **sbp = nilfs->ns_sbp;
276 	time64_t t;
277 
278 	/* nilfs->ns_sem must be locked by the caller. */
279 	t = ktime_get_real_seconds();
280 	nilfs->ns_sbwtime = t;
281 	sbp[0]->s_wtime = cpu_to_le64(t);
282 	sbp[0]->s_sum = 0;
283 	sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
284 					     (unsigned char *)sbp[0],
285 					     nilfs->ns_sbsize));
286 	if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
287 		sbp[1]->s_wtime = sbp[0]->s_wtime;
288 		sbp[1]->s_sum = 0;
289 		sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
290 					    (unsigned char *)sbp[1],
291 					    nilfs->ns_sbsize));
292 	}
293 	clear_nilfs_sb_dirty(nilfs);
294 	nilfs->ns_flushed_device = 1;
295 	/* make sure store to ns_flushed_device cannot be reordered */
296 	smp_wmb();
297 	return nilfs_sync_super(sb, flag);
298 }
299 
300 /**
301  * nilfs_cleanup_super() - write filesystem state for cleanup
302  * @sb: super block instance to be unmounted or degraded to read-only
303  *
304  * This function restores state flags in the on-disk super block.
305  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
306  * filesystem was not clean previously.
307  */
308 int nilfs_cleanup_super(struct super_block *sb)
309 {
310 	struct the_nilfs *nilfs = sb->s_fs_info;
311 	struct nilfs_super_block **sbp;
312 	int flag = NILFS_SB_COMMIT;
313 	int ret = -EIO;
314 
315 	sbp = nilfs_prepare_super(sb, 0);
316 	if (sbp) {
317 		sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
318 		nilfs_set_log_cursor(sbp[0], nilfs);
319 		if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
320 			/*
321 			 * make the "clean" flag also to the opposite
322 			 * super block if both super blocks point to
323 			 * the same checkpoint.
324 			 */
325 			sbp[1]->s_state = sbp[0]->s_state;
326 			flag = NILFS_SB_COMMIT_ALL;
327 		}
328 		ret = nilfs_commit_super(sb, flag);
329 	}
330 	return ret;
331 }
332 
333 /**
334  * nilfs_move_2nd_super - relocate secondary super block
335  * @sb: super block instance
336  * @sb2off: new offset of the secondary super block (in bytes)
337  */
338 static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
339 {
340 	struct the_nilfs *nilfs = sb->s_fs_info;
341 	struct buffer_head *nsbh;
342 	struct nilfs_super_block *nsbp;
343 	sector_t blocknr, newblocknr;
344 	unsigned long offset;
345 	int sb2i;  /* array index of the secondary superblock */
346 	int ret = 0;
347 
348 	/* nilfs->ns_sem must be locked by the caller. */
349 	if (nilfs->ns_sbh[1] &&
350 	    nilfs->ns_sbh[1]->b_blocknr > nilfs->ns_first_data_block) {
351 		sb2i = 1;
352 		blocknr = nilfs->ns_sbh[1]->b_blocknr;
353 	} else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
354 		sb2i = 0;
355 		blocknr = nilfs->ns_sbh[0]->b_blocknr;
356 	} else {
357 		sb2i = -1;
358 		blocknr = 0;
359 	}
360 	if (sb2i >= 0 && (u64)blocknr << nilfs->ns_blocksize_bits == sb2off)
361 		goto out;  /* super block location is unchanged */
362 
363 	/* Get new super block buffer */
364 	newblocknr = sb2off >> nilfs->ns_blocksize_bits;
365 	offset = sb2off & (nilfs->ns_blocksize - 1);
366 	nsbh = sb_getblk(sb, newblocknr);
367 	if (!nsbh) {
368 		nilfs_warn(sb,
369 			   "unable to move secondary superblock to block %llu",
370 			   (unsigned long long)newblocknr);
371 		ret = -EIO;
372 		goto out;
373 	}
374 	nsbp = (void *)nsbh->b_data + offset;
375 
376 	lock_buffer(nsbh);
377 	if (sb2i >= 0) {
378 		/*
379 		 * The position of the second superblock only changes by 4KiB,
380 		 * which is larger than the maximum superblock data size
381 		 * (= 1KiB), so there is no need to use memmove() to allow
382 		 * overlap between source and destination.
383 		 */
384 		memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
385 
386 		/*
387 		 * Zero fill after copy to avoid overwriting in case of move
388 		 * within the same block.
389 		 */
390 		memset(nsbh->b_data, 0, offset);
391 		memset((void *)nsbp + nilfs->ns_sbsize, 0,
392 		       nsbh->b_size - offset - nilfs->ns_sbsize);
393 	} else {
394 		memset(nsbh->b_data, 0, nsbh->b_size);
395 	}
396 	set_buffer_uptodate(nsbh);
397 	unlock_buffer(nsbh);
398 
399 	if (sb2i >= 0) {
400 		brelse(nilfs->ns_sbh[sb2i]);
401 		nilfs->ns_sbh[sb2i] = nsbh;
402 		nilfs->ns_sbp[sb2i] = nsbp;
403 	} else if (nilfs->ns_sbh[0]->b_blocknr < nilfs->ns_first_data_block) {
404 		/* secondary super block will be restored to index 1 */
405 		nilfs->ns_sbh[1] = nsbh;
406 		nilfs->ns_sbp[1] = nsbp;
407 	} else {
408 		brelse(nsbh);
409 	}
410 out:
411 	return ret;
412 }
413 
414 /**
415  * nilfs_resize_fs - resize the filesystem
416  * @sb: super block instance
417  * @newsize: new size of the filesystem (in bytes)
418  */
419 int nilfs_resize_fs(struct super_block *sb, __u64 newsize)
420 {
421 	struct the_nilfs *nilfs = sb->s_fs_info;
422 	struct nilfs_super_block **sbp;
423 	__u64 devsize, newnsegs;
424 	loff_t sb2off;
425 	int ret;
426 
427 	ret = -ERANGE;
428 	devsize = bdev_nr_bytes(sb->s_bdev);
429 	if (newsize > devsize)
430 		goto out;
431 
432 	/*
433 	 * Prevent underflow in second superblock position calculation.
434 	 * The exact minimum size check is done in nilfs_sufile_resize().
435 	 */
436 	if (newsize < 4096) {
437 		ret = -ENOSPC;
438 		goto out;
439 	}
440 
441 	/*
442 	 * Write lock is required to protect some functions depending
443 	 * on the number of segments, the number of reserved segments,
444 	 * and so forth.
445 	 */
446 	down_write(&nilfs->ns_segctor_sem);
447 
448 	sb2off = NILFS_SB2_OFFSET_BYTES(newsize);
449 	newnsegs = sb2off >> nilfs->ns_blocksize_bits;
450 	newnsegs = div64_ul(newnsegs, nilfs->ns_blocks_per_segment);
451 
452 	ret = nilfs_sufile_resize(nilfs->ns_sufile, newnsegs);
453 	up_write(&nilfs->ns_segctor_sem);
454 	if (ret < 0)
455 		goto out;
456 
457 	ret = nilfs_construct_segment(sb);
458 	if (ret < 0)
459 		goto out;
460 
461 	down_write(&nilfs->ns_sem);
462 	nilfs_move_2nd_super(sb, sb2off);
463 	ret = -EIO;
464 	sbp = nilfs_prepare_super(sb, 0);
465 	if (likely(sbp)) {
466 		nilfs_set_log_cursor(sbp[0], nilfs);
467 		/*
468 		 * Drop NILFS_RESIZE_FS flag for compatibility with
469 		 * mount-time resize which may be implemented in a
470 		 * future release.
471 		 */
472 		sbp[0]->s_state = cpu_to_le16(le16_to_cpu(sbp[0]->s_state) &
473 					      ~NILFS_RESIZE_FS);
474 		sbp[0]->s_dev_size = cpu_to_le64(newsize);
475 		sbp[0]->s_nsegments = cpu_to_le64(nilfs->ns_nsegments);
476 		if (sbp[1])
477 			memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
478 		ret = nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
479 	}
480 	up_write(&nilfs->ns_sem);
481 
482 	/*
483 	 * Reset the range of allocatable segments last.  This order
484 	 * is important in the case of expansion because the secondary
485 	 * superblock must be protected from log write until migration
486 	 * completes.
487 	 */
488 	if (!ret)
489 		nilfs_sufile_set_alloc_range(nilfs->ns_sufile, 0, newnsegs - 1);
490 out:
491 	return ret;
492 }
493 
494 static void nilfs_put_super(struct super_block *sb)
495 {
496 	struct the_nilfs *nilfs = sb->s_fs_info;
497 
498 	nilfs_detach_log_writer(sb);
499 
500 	if (!sb_rdonly(sb)) {
501 		down_write(&nilfs->ns_sem);
502 		nilfs_cleanup_super(sb);
503 		up_write(&nilfs->ns_sem);
504 	}
505 
506 	nilfs_sysfs_delete_device_group(nilfs);
507 	iput(nilfs->ns_sufile);
508 	iput(nilfs->ns_cpfile);
509 	iput(nilfs->ns_dat);
510 
511 	destroy_nilfs(nilfs);
512 	sb->s_fs_info = NULL;
513 }
514 
515 static int nilfs_sync_fs(struct super_block *sb, int wait)
516 {
517 	struct the_nilfs *nilfs = sb->s_fs_info;
518 	struct nilfs_super_block **sbp;
519 	int err = 0;
520 
521 	/* This function is called when super block should be written back */
522 	if (wait)
523 		err = nilfs_construct_segment(sb);
524 
525 	down_write(&nilfs->ns_sem);
526 	if (nilfs_sb_dirty(nilfs)) {
527 		sbp = nilfs_prepare_super(sb, nilfs_sb_will_flip(nilfs));
528 		if (likely(sbp)) {
529 			nilfs_set_log_cursor(sbp[0], nilfs);
530 			nilfs_commit_super(sb, NILFS_SB_COMMIT);
531 		}
532 	}
533 	up_write(&nilfs->ns_sem);
534 
535 	if (!err)
536 		err = nilfs_flush_device(nilfs);
537 
538 	return err;
539 }
540 
541 int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
542 			    struct nilfs_root **rootp)
543 {
544 	struct the_nilfs *nilfs = sb->s_fs_info;
545 	struct nilfs_root *root;
546 	int err = -ENOMEM;
547 
548 	root = nilfs_find_or_create_root(
549 		nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
550 	if (!root)
551 		return err;
552 
553 	if (root->ifile)
554 		goto reuse; /* already attached checkpoint */
555 
556 	down_read(&nilfs->ns_segctor_sem);
557 	err = nilfs_ifile_read(sb, root, cno, nilfs->ns_inode_size);
558 	up_read(&nilfs->ns_segctor_sem);
559 	if (unlikely(err))
560 		goto failed;
561 
562  reuse:
563 	*rootp = root;
564 	return 0;
565 
566  failed:
567 	if (err == -EINVAL)
568 		nilfs_err(sb, "Invalid checkpoint (checkpoint number=%llu)",
569 			  (unsigned long long)cno);
570 	nilfs_put_root(root);
571 
572 	return err;
573 }
574 
575 static int nilfs_freeze(struct super_block *sb)
576 {
577 	struct the_nilfs *nilfs = sb->s_fs_info;
578 	int err;
579 
580 	if (sb_rdonly(sb))
581 		return 0;
582 
583 	/* Mark super block clean */
584 	down_write(&nilfs->ns_sem);
585 	err = nilfs_cleanup_super(sb);
586 	up_write(&nilfs->ns_sem);
587 	return err;
588 }
589 
590 static int nilfs_unfreeze(struct super_block *sb)
591 {
592 	struct the_nilfs *nilfs = sb->s_fs_info;
593 
594 	if (sb_rdonly(sb))
595 		return 0;
596 
597 	down_write(&nilfs->ns_sem);
598 	nilfs_setup_super(sb, false);
599 	up_write(&nilfs->ns_sem);
600 	return 0;
601 }
602 
603 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
604 {
605 	struct super_block *sb = dentry->d_sb;
606 	struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
607 	struct the_nilfs *nilfs = root->nilfs;
608 	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
609 	unsigned long long blocks;
610 	unsigned long overhead;
611 	unsigned long nrsvblocks;
612 	sector_t nfreeblocks;
613 	u64 nmaxinodes, nfreeinodes;
614 	int err;
615 
616 	/*
617 	 * Compute all of the segment blocks
618 	 *
619 	 * The blocks before first segment and after last segment
620 	 * are excluded.
621 	 */
622 	blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
623 		- nilfs->ns_first_data_block;
624 	nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
625 
626 	/*
627 	 * Compute the overhead
628 	 *
629 	 * When distributing meta data blocks outside segment structure,
630 	 * We must count them as the overhead.
631 	 */
632 	overhead = 0;
633 
634 	err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
635 	if (unlikely(err))
636 		return err;
637 
638 	err = nilfs_ifile_count_free_inodes(root->ifile,
639 					    &nmaxinodes, &nfreeinodes);
640 	if (unlikely(err)) {
641 		nilfs_warn(sb, "failed to count free inodes: err=%d", err);
642 		if (err == -ERANGE) {
643 			/*
644 			 * If nilfs_palloc_count_max_entries() returns
645 			 * -ERANGE error code then we simply treat
646 			 * curent inodes count as maximum possible and
647 			 * zero as free inodes value.
648 			 */
649 			nmaxinodes = atomic64_read(&root->inodes_count);
650 			nfreeinodes = 0;
651 			err = 0;
652 		} else
653 			return err;
654 	}
655 
656 	buf->f_type = NILFS_SUPER_MAGIC;
657 	buf->f_bsize = sb->s_blocksize;
658 	buf->f_blocks = blocks - overhead;
659 	buf->f_bfree = nfreeblocks;
660 	buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
661 		(buf->f_bfree - nrsvblocks) : 0;
662 	buf->f_files = nmaxinodes;
663 	buf->f_ffree = nfreeinodes;
664 	buf->f_namelen = NILFS_NAME_LEN;
665 	buf->f_fsid = u64_to_fsid(id);
666 
667 	return 0;
668 }
669 
670 static int nilfs_show_options(struct seq_file *seq, struct dentry *dentry)
671 {
672 	struct super_block *sb = dentry->d_sb;
673 	struct the_nilfs *nilfs = sb->s_fs_info;
674 	struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
675 
676 	if (!nilfs_test_opt(nilfs, BARRIER))
677 		seq_puts(seq, ",nobarrier");
678 	if (root->cno != NILFS_CPTREE_CURRENT_CNO)
679 		seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
680 	if (nilfs_test_opt(nilfs, ERRORS_PANIC))
681 		seq_puts(seq, ",errors=panic");
682 	if (nilfs_test_opt(nilfs, ERRORS_CONT))
683 		seq_puts(seq, ",errors=continue");
684 	if (nilfs_test_opt(nilfs, STRICT_ORDER))
685 		seq_puts(seq, ",order=strict");
686 	if (nilfs_test_opt(nilfs, NORECOVERY))
687 		seq_puts(seq, ",norecovery");
688 	if (nilfs_test_opt(nilfs, DISCARD))
689 		seq_puts(seq, ",discard");
690 
691 	return 0;
692 }
693 
694 static const struct super_operations nilfs_sops = {
695 	.alloc_inode    = nilfs_alloc_inode,
696 	.free_inode     = nilfs_free_inode,
697 	.dirty_inode    = nilfs_dirty_inode,
698 	.evict_inode    = nilfs_evict_inode,
699 	.put_super      = nilfs_put_super,
700 	.sync_fs        = nilfs_sync_fs,
701 	.freeze_fs	= nilfs_freeze,
702 	.unfreeze_fs	= nilfs_unfreeze,
703 	.statfs         = nilfs_statfs,
704 	.show_options = nilfs_show_options
705 };
706 
707 enum {
708 	Opt_err, Opt_barrier, Opt_snapshot, Opt_order, Opt_norecovery,
709 	Opt_discard,
710 };
711 
712 static const struct constant_table nilfs_param_err[] = {
713 	{"continue",	NILFS_MOUNT_ERRORS_CONT},
714 	{"panic",	NILFS_MOUNT_ERRORS_PANIC},
715 	{"remount-ro",	NILFS_MOUNT_ERRORS_RO},
716 	{}
717 };
718 
719 static const struct fs_parameter_spec nilfs_param_spec[] = {
720 	fsparam_enum	("errors", Opt_err, nilfs_param_err),
721 	fsparam_flag_no	("barrier", Opt_barrier),
722 	fsparam_u64	("cp", Opt_snapshot),
723 	fsparam_string	("order", Opt_order),
724 	fsparam_flag	("norecovery", Opt_norecovery),
725 	fsparam_flag_no	("discard", Opt_discard),
726 	{}
727 };
728 
729 struct nilfs_fs_context {
730 	unsigned long ns_mount_opt;
731 	__u64 cno;
732 };
733 
734 static int nilfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
735 {
736 	struct nilfs_fs_context *nilfs = fc->fs_private;
737 	int is_remount = fc->purpose == FS_CONTEXT_FOR_RECONFIGURE;
738 	struct fs_parse_result result;
739 	int opt;
740 
741 	opt = fs_parse(fc, nilfs_param_spec, param, &result);
742 	if (opt < 0)
743 		return opt;
744 
745 	switch (opt) {
746 	case Opt_barrier:
747 		if (result.negated)
748 			nilfs_clear_opt(nilfs, BARRIER);
749 		else
750 			nilfs_set_opt(nilfs, BARRIER);
751 		break;
752 	case Opt_order:
753 		if (strcmp(param->string, "relaxed") == 0)
754 			/* Ordered data semantics */
755 			nilfs_clear_opt(nilfs, STRICT_ORDER);
756 		else if (strcmp(param->string, "strict") == 0)
757 			/* Strict in-order semantics */
758 			nilfs_set_opt(nilfs, STRICT_ORDER);
759 		else
760 			return -EINVAL;
761 		break;
762 	case Opt_err:
763 		nilfs->ns_mount_opt &= ~NILFS_MOUNT_ERROR_MODE;
764 		nilfs->ns_mount_opt |= result.uint_32;
765 		break;
766 	case Opt_snapshot:
767 		if (is_remount) {
768 			struct super_block *sb = fc->root->d_sb;
769 
770 			nilfs_err(sb,
771 				  "\"%s\" option is invalid for remount",
772 				  param->key);
773 			return -EINVAL;
774 		}
775 		if (result.uint_64 == 0) {
776 			nilfs_err(NULL,
777 				  "invalid option \"cp=0\": invalid checkpoint number 0");
778 			return -EINVAL;
779 		}
780 		nilfs->cno = result.uint_64;
781 		break;
782 	case Opt_norecovery:
783 		nilfs_set_opt(nilfs, NORECOVERY);
784 		break;
785 	case Opt_discard:
786 		if (result.negated)
787 			nilfs_clear_opt(nilfs, DISCARD);
788 		else
789 			nilfs_set_opt(nilfs, DISCARD);
790 		break;
791 	default:
792 		return -EINVAL;
793 	}
794 
795 	return 0;
796 }
797 
798 static int nilfs_setup_super(struct super_block *sb, int is_mount)
799 {
800 	struct the_nilfs *nilfs = sb->s_fs_info;
801 	struct nilfs_super_block **sbp;
802 	int max_mnt_count;
803 	int mnt_count;
804 
805 	/* nilfs->ns_sem must be locked by the caller. */
806 	sbp = nilfs_prepare_super(sb, 0);
807 	if (!sbp)
808 		return -EIO;
809 
810 	if (!is_mount)
811 		goto skip_mount_setup;
812 
813 	max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
814 	mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
815 
816 	if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
817 		nilfs_warn(sb, "mounting fs with errors");
818 #if 0
819 	} else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
820 		nilfs_warn(sb, "maximal mount count reached");
821 #endif
822 	}
823 	if (!max_mnt_count)
824 		sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
825 
826 	sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
827 	sbp[0]->s_mtime = cpu_to_le64(ktime_get_real_seconds());
828 
829 skip_mount_setup:
830 	sbp[0]->s_state =
831 		cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
832 	/* synchronize sbp[1] with sbp[0] */
833 	if (sbp[1])
834 		memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
835 	return nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
836 }
837 
838 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
839 						 u64 pos, int blocksize,
840 						 struct buffer_head **pbh)
841 {
842 	unsigned long long sb_index = pos;
843 	unsigned long offset;
844 
845 	offset = do_div(sb_index, blocksize);
846 	*pbh = sb_bread(sb, sb_index);
847 	if (!*pbh)
848 		return NULL;
849 	return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
850 }
851 
852 int nilfs_store_magic(struct super_block *sb,
853 		      struct nilfs_super_block *sbp)
854 {
855 	struct the_nilfs *nilfs = sb->s_fs_info;
856 
857 	sb->s_magic = le16_to_cpu(sbp->s_magic);
858 
859 	/* FS independent flags */
860 #ifdef NILFS_ATIME_DISABLE
861 	sb->s_flags |= SB_NOATIME;
862 #endif
863 
864 	nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
865 	nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
866 	nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
867 	nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
868 
869 	return 0;
870 }
871 
872 int nilfs_check_feature_compatibility(struct super_block *sb,
873 				      struct nilfs_super_block *sbp)
874 {
875 	__u64 features;
876 
877 	features = le64_to_cpu(sbp->s_feature_incompat) &
878 		~NILFS_FEATURE_INCOMPAT_SUPP;
879 	if (features) {
880 		nilfs_err(sb,
881 			  "couldn't mount because of unsupported optional features (%llx)",
882 			  (unsigned long long)features);
883 		return -EINVAL;
884 	}
885 	features = le64_to_cpu(sbp->s_feature_compat_ro) &
886 		~NILFS_FEATURE_COMPAT_RO_SUPP;
887 	if (!sb_rdonly(sb) && features) {
888 		nilfs_err(sb,
889 			  "couldn't mount RDWR because of unsupported optional features (%llx)",
890 			  (unsigned long long)features);
891 		return -EINVAL;
892 	}
893 	return 0;
894 }
895 
896 static int nilfs_get_root_dentry(struct super_block *sb,
897 				 struct nilfs_root *root,
898 				 struct dentry **root_dentry)
899 {
900 	struct inode *inode;
901 	struct dentry *dentry;
902 	int ret = 0;
903 
904 	inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
905 	if (IS_ERR(inode)) {
906 		ret = PTR_ERR(inode);
907 		nilfs_err(sb, "error %d getting root inode", ret);
908 		goto out;
909 	}
910 	if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
911 		iput(inode);
912 		nilfs_err(sb, "corrupt root inode");
913 		ret = -EINVAL;
914 		goto out;
915 	}
916 
917 	if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
918 		dentry = d_find_alias(inode);
919 		if (!dentry) {
920 			dentry = d_make_root(inode);
921 			if (!dentry) {
922 				ret = -ENOMEM;
923 				goto failed_dentry;
924 			}
925 		} else {
926 			iput(inode);
927 		}
928 	} else {
929 		dentry = d_obtain_root(inode);
930 		if (IS_ERR(dentry)) {
931 			ret = PTR_ERR(dentry);
932 			goto failed_dentry;
933 		}
934 	}
935 	*root_dentry = dentry;
936  out:
937 	return ret;
938 
939  failed_dentry:
940 	nilfs_err(sb, "error %d getting root dentry", ret);
941 	goto out;
942 }
943 
944 static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
945 				 struct dentry **root_dentry)
946 {
947 	struct the_nilfs *nilfs = s->s_fs_info;
948 	struct nilfs_root *root;
949 	int ret;
950 
951 	mutex_lock(&nilfs->ns_snapshot_mount_mutex);
952 
953 	down_read(&nilfs->ns_segctor_sem);
954 	ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
955 	up_read(&nilfs->ns_segctor_sem);
956 	if (ret < 0) {
957 		ret = (ret == -ENOENT) ? -EINVAL : ret;
958 		goto out;
959 	} else if (!ret) {
960 		nilfs_err(s,
961 			  "The specified checkpoint is not a snapshot (checkpoint number=%llu)",
962 			  (unsigned long long)cno);
963 		ret = -EINVAL;
964 		goto out;
965 	}
966 
967 	ret = nilfs_attach_checkpoint(s, cno, false, &root);
968 	if (ret) {
969 		nilfs_err(s,
970 			  "error %d while loading snapshot (checkpoint number=%llu)",
971 			  ret, (unsigned long long)cno);
972 		goto out;
973 	}
974 	ret = nilfs_get_root_dentry(s, root, root_dentry);
975 	nilfs_put_root(root);
976  out:
977 	mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
978 	return ret;
979 }
980 
981 /**
982  * nilfs_tree_is_busy() - try to shrink dentries of a checkpoint
983  * @root_dentry: root dentry of the tree to be shrunk
984  *
985  * This function returns true if the tree was in-use.
986  */
987 static bool nilfs_tree_is_busy(struct dentry *root_dentry)
988 {
989 	shrink_dcache_parent(root_dentry);
990 	return d_count(root_dentry) > 1;
991 }
992 
993 int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
994 {
995 	struct the_nilfs *nilfs = sb->s_fs_info;
996 	struct nilfs_root *root;
997 	struct inode *inode;
998 	struct dentry *dentry;
999 	int ret;
1000 
1001 	if (cno > nilfs->ns_cno)
1002 		return false;
1003 
1004 	if (cno >= nilfs_last_cno(nilfs))
1005 		return true;	/* protect recent checkpoints */
1006 
1007 	ret = false;
1008 	root = nilfs_lookup_root(nilfs, cno);
1009 	if (root) {
1010 		inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
1011 		if (inode) {
1012 			dentry = d_find_alias(inode);
1013 			if (dentry) {
1014 				ret = nilfs_tree_is_busy(dentry);
1015 				dput(dentry);
1016 			}
1017 			iput(inode);
1018 		}
1019 		nilfs_put_root(root);
1020 	}
1021 	return ret;
1022 }
1023 
1024 /**
1025  * nilfs_fill_super() - initialize a super block instance
1026  * @sb: super_block
1027  * @fc: filesystem context
1028  *
1029  * This function is called exclusively by nilfs->ns_mount_mutex.
1030  * So, the recovery process is protected from other simultaneous mounts.
1031  */
1032 static int
1033 nilfs_fill_super(struct super_block *sb, struct fs_context *fc)
1034 {
1035 	struct the_nilfs *nilfs;
1036 	struct nilfs_root *fsroot;
1037 	struct nilfs_fs_context *ctx = fc->fs_private;
1038 	__u64 cno;
1039 	int err;
1040 
1041 	nilfs = alloc_nilfs(sb);
1042 	if (!nilfs)
1043 		return -ENOMEM;
1044 
1045 	sb->s_fs_info = nilfs;
1046 
1047 	err = init_nilfs(nilfs, sb);
1048 	if (err)
1049 		goto failed_nilfs;
1050 
1051 	/* Copy in parsed mount options */
1052 	nilfs->ns_mount_opt = ctx->ns_mount_opt;
1053 
1054 	sb->s_op = &nilfs_sops;
1055 	sb->s_export_op = &nilfs_export_ops;
1056 	sb->s_root = NULL;
1057 	sb->s_time_gran = 1;
1058 	sb->s_max_links = NILFS_LINK_MAX;
1059 
1060 	sb->s_bdi = bdi_get(sb->s_bdev->bd_disk->bdi);
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 		nilfs_err(sb,
1070 			  "error %d while loading last checkpoint (checkpoint number=%llu)",
1071 			  err, (unsigned long long)cno);
1072 		goto failed_unload;
1073 	}
1074 
1075 	if (!sb_rdonly(sb)) {
1076 		err = nilfs_attach_log_writer(sb, fsroot);
1077 		if (err)
1078 			goto failed_checkpoint;
1079 	}
1080 
1081 	err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
1082 	if (err)
1083 		goto failed_segctor;
1084 
1085 	nilfs_put_root(fsroot);
1086 
1087 	if (!sb_rdonly(sb)) {
1088 		down_write(&nilfs->ns_sem);
1089 		nilfs_setup_super(sb, true);
1090 		up_write(&nilfs->ns_sem);
1091 	}
1092 
1093 	return 0;
1094 
1095  failed_segctor:
1096 	nilfs_detach_log_writer(sb);
1097 
1098  failed_checkpoint:
1099 	nilfs_put_root(fsroot);
1100 
1101  failed_unload:
1102 	nilfs_sysfs_delete_device_group(nilfs);
1103 	iput(nilfs->ns_sufile);
1104 	iput(nilfs->ns_cpfile);
1105 	iput(nilfs->ns_dat);
1106 
1107  failed_nilfs:
1108 	destroy_nilfs(nilfs);
1109 	return err;
1110 }
1111 
1112 static int nilfs_reconfigure(struct fs_context *fc)
1113 {
1114 	struct nilfs_fs_context *ctx = fc->fs_private;
1115 	struct super_block *sb = fc->root->d_sb;
1116 	struct the_nilfs *nilfs = sb->s_fs_info;
1117 	int err;
1118 
1119 	sync_filesystem(sb);
1120 
1121 	err = -EINVAL;
1122 
1123 	if (!nilfs_valid_fs(nilfs)) {
1124 		nilfs_warn(sb,
1125 			   "couldn't remount because the filesystem is in an incomplete recovery state");
1126 		goto ignore_opts;
1127 	}
1128 	if ((bool)(fc->sb_flags & SB_RDONLY) == sb_rdonly(sb))
1129 		goto out;
1130 	if (fc->sb_flags & SB_RDONLY) {
1131 		sb->s_flags |= SB_RDONLY;
1132 
1133 		/*
1134 		 * Remounting a valid RW partition RDONLY, so set
1135 		 * the RDONLY flag and then mark the partition as valid again.
1136 		 */
1137 		down_write(&nilfs->ns_sem);
1138 		nilfs_cleanup_super(sb);
1139 		up_write(&nilfs->ns_sem);
1140 	} else {
1141 		__u64 features;
1142 		struct nilfs_root *root;
1143 
1144 		/*
1145 		 * Mounting a RDONLY partition read-write, so reread and
1146 		 * store the current valid flag.  (It may have been changed
1147 		 * by fsck since we originally mounted the partition.)
1148 		 */
1149 		down_read(&nilfs->ns_sem);
1150 		features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1151 			~NILFS_FEATURE_COMPAT_RO_SUPP;
1152 		up_read(&nilfs->ns_sem);
1153 		if (features) {
1154 			nilfs_warn(sb,
1155 				   "couldn't remount RDWR because of unsupported optional features (%llx)",
1156 				   (unsigned long long)features);
1157 			err = -EROFS;
1158 			goto ignore_opts;
1159 		}
1160 
1161 		sb->s_flags &= ~SB_RDONLY;
1162 
1163 		root = NILFS_I(d_inode(sb->s_root))->i_root;
1164 		err = nilfs_attach_log_writer(sb, root);
1165 		if (err) {
1166 			sb->s_flags |= SB_RDONLY;
1167 			goto ignore_opts;
1168 		}
1169 
1170 		down_write(&nilfs->ns_sem);
1171 		nilfs_setup_super(sb, true);
1172 		up_write(&nilfs->ns_sem);
1173 	}
1174  out:
1175 	sb->s_flags = (sb->s_flags & ~SB_POSIXACL);
1176 	/* Copy over parsed remount options */
1177 	nilfs->ns_mount_opt = ctx->ns_mount_opt;
1178 
1179 	return 0;
1180 
1181  ignore_opts:
1182 	return err;
1183 }
1184 
1185 static int
1186 nilfs_get_tree(struct fs_context *fc)
1187 {
1188 	struct nilfs_fs_context *ctx = fc->fs_private;
1189 	struct super_block *s;
1190 	dev_t dev;
1191 	int err;
1192 
1193 	if (ctx->cno && !(fc->sb_flags & SB_RDONLY)) {
1194 		nilfs_err(NULL,
1195 			  "invalid option \"cp=%llu\": read-only option is not specified",
1196 			  ctx->cno);
1197 		return -EINVAL;
1198 	}
1199 
1200 	err = lookup_bdev(fc->source, &dev);
1201 	if (err)
1202 		return err;
1203 
1204 	s = sget_dev(fc, dev);
1205 	if (IS_ERR(s))
1206 		return PTR_ERR(s);
1207 
1208 	if (!s->s_root) {
1209 		err = setup_bdev_super(s, fc->sb_flags, fc);
1210 		if (!err)
1211 			err = nilfs_fill_super(s, fc);
1212 		if (err)
1213 			goto failed_super;
1214 
1215 		s->s_flags |= SB_ACTIVE;
1216 	} else if (!ctx->cno) {
1217 		if (nilfs_tree_is_busy(s->s_root)) {
1218 			if ((fc->sb_flags ^ s->s_flags) & SB_RDONLY) {
1219 				nilfs_err(s,
1220 					  "the device already has a %s mount.",
1221 					  sb_rdonly(s) ? "read-only" : "read/write");
1222 				err = -EBUSY;
1223 				goto failed_super;
1224 			}
1225 		} else {
1226 			/*
1227 			 * Try reconfigure to setup mount states if the current
1228 			 * tree is not mounted and only snapshots use this sb.
1229 			 *
1230 			 * Since nilfs_reconfigure() requires fc->root to be
1231 			 * set, set it first and release it on failure.
1232 			 */
1233 			fc->root = dget(s->s_root);
1234 			err = nilfs_reconfigure(fc);
1235 			if (err) {
1236 				dput(fc->root);
1237 				fc->root = NULL;  /* prevent double release */
1238 				goto failed_super;
1239 			}
1240 			return 0;
1241 		}
1242 	}
1243 
1244 	if (ctx->cno) {
1245 		struct dentry *root_dentry;
1246 
1247 		err = nilfs_attach_snapshot(s, ctx->cno, &root_dentry);
1248 		if (err)
1249 			goto failed_super;
1250 		fc->root = root_dentry;
1251 		return 0;
1252 	}
1253 
1254 	fc->root = dget(s->s_root);
1255 	return 0;
1256 
1257  failed_super:
1258 	deactivate_locked_super(s);
1259 	return err;
1260 }
1261 
1262 static void nilfs_free_fc(struct fs_context *fc)
1263 {
1264 	kfree(fc->fs_private);
1265 }
1266 
1267 static const struct fs_context_operations nilfs_context_ops = {
1268 	.parse_param	= nilfs_parse_param,
1269 	.get_tree	= nilfs_get_tree,
1270 	.reconfigure	= nilfs_reconfigure,
1271 	.free		= nilfs_free_fc,
1272 };
1273 
1274 static int nilfs_init_fs_context(struct fs_context *fc)
1275 {
1276 	struct nilfs_fs_context *ctx;
1277 
1278 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
1279 	if (!ctx)
1280 		return -ENOMEM;
1281 
1282 	ctx->ns_mount_opt = NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
1283 	fc->fs_private = ctx;
1284 	fc->ops = &nilfs_context_ops;
1285 
1286 	return 0;
1287 }
1288 
1289 struct file_system_type nilfs_fs_type = {
1290 	.owner    = THIS_MODULE,
1291 	.name     = "nilfs2",
1292 	.kill_sb  = kill_block_super,
1293 	.fs_flags = FS_REQUIRES_DEV,
1294 	.init_fs_context = nilfs_init_fs_context,
1295 	.parameters = nilfs_param_spec,
1296 };
1297 MODULE_ALIAS_FS("nilfs2");
1298 
1299 static void nilfs_inode_init_once(void *obj)
1300 {
1301 	struct nilfs_inode_info *ii = obj;
1302 
1303 	INIT_LIST_HEAD(&ii->i_dirty);
1304 #ifdef CONFIG_NILFS_XATTR
1305 	init_rwsem(&ii->xattr_sem);
1306 #endif
1307 	inode_init_once(&ii->vfs_inode);
1308 }
1309 
1310 static void nilfs_segbuf_init_once(void *obj)
1311 {
1312 	memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1313 }
1314 
1315 static void nilfs_destroy_cachep(void)
1316 {
1317 	/*
1318 	 * Make sure all delayed rcu free inodes are flushed before we
1319 	 * destroy cache.
1320 	 */
1321 	rcu_barrier();
1322 
1323 	kmem_cache_destroy(nilfs_inode_cachep);
1324 	kmem_cache_destroy(nilfs_transaction_cachep);
1325 	kmem_cache_destroy(nilfs_segbuf_cachep);
1326 	kmem_cache_destroy(nilfs_btree_path_cache);
1327 }
1328 
1329 static int __init nilfs_init_cachep(void)
1330 {
1331 	nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1332 			sizeof(struct nilfs_inode_info), 0,
1333 			SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
1334 			nilfs_inode_init_once);
1335 	if (!nilfs_inode_cachep)
1336 		goto fail;
1337 
1338 	nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1339 			sizeof(struct nilfs_transaction_info), 0,
1340 			SLAB_RECLAIM_ACCOUNT, NULL);
1341 	if (!nilfs_transaction_cachep)
1342 		goto fail;
1343 
1344 	nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1345 			sizeof(struct nilfs_segment_buffer), 0,
1346 			SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1347 	if (!nilfs_segbuf_cachep)
1348 		goto fail;
1349 
1350 	nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1351 			sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1352 			0, 0, NULL);
1353 	if (!nilfs_btree_path_cache)
1354 		goto fail;
1355 
1356 	return 0;
1357 
1358 fail:
1359 	nilfs_destroy_cachep();
1360 	return -ENOMEM;
1361 }
1362 
1363 static int __init init_nilfs_fs(void)
1364 {
1365 	int err;
1366 
1367 	err = nilfs_init_cachep();
1368 	if (err)
1369 		goto fail;
1370 
1371 	err = nilfs_sysfs_init();
1372 	if (err)
1373 		goto free_cachep;
1374 
1375 	err = register_filesystem(&nilfs_fs_type);
1376 	if (err)
1377 		goto deinit_sysfs_entry;
1378 
1379 	printk(KERN_INFO "NILFS version 2 loaded\n");
1380 	return 0;
1381 
1382 deinit_sysfs_entry:
1383 	nilfs_sysfs_exit();
1384 free_cachep:
1385 	nilfs_destroy_cachep();
1386 fail:
1387 	return err;
1388 }
1389 
1390 static void __exit exit_nilfs_fs(void)
1391 {
1392 	nilfs_destroy_cachep();
1393 	nilfs_sysfs_exit();
1394 	unregister_filesystem(&nilfs_fs_type);
1395 }
1396 
1397 module_init(init_nilfs_fs)
1398 module_exit(exit_nilfs_fs)
1399