1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * NILFS checkpoint file.
4 *
5 * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
6 *
7 * Written by Koji Sato.
8 */
9
10 #include <linux/kernel.h>
11 #include <linux/fs.h>
12 #include <linux/string.h>
13 #include <linux/buffer_head.h>
14 #include <linux/errno.h>
15 #include "mdt.h"
16 #include "cpfile.h"
17
18
19 static inline unsigned long
20 nilfs_cpfile_checkpoints_per_block(const struct inode *cpfile)
21 {
22 return NILFS_MDT(cpfile)->mi_entries_per_block;
23 }
24
25 /* block number from the beginning of the file */
26 static unsigned long
27 nilfs_cpfile_get_blkoff(const struct inode *cpfile, __u64 cno)
28 {
29 __u64 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
30
31 tcno = div64_ul(tcno, nilfs_cpfile_checkpoints_per_block(cpfile));
32 return (unsigned long)tcno;
33 }
34
35 /* offset in block */
36 static unsigned long
37 nilfs_cpfile_get_offset(const struct inode *cpfile, __u64 cno)
38 {
39 __u64 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
40
41 return do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile));
42 }
43
44 static __u64 nilfs_cpfile_first_checkpoint_in_block(const struct inode *cpfile,
45 unsigned long blkoff)
46 {
47 return (__u64)nilfs_cpfile_checkpoints_per_block(cpfile) * blkoff
48 + 1 - NILFS_MDT(cpfile)->mi_first_entry_offset;
49 }
50
51 static unsigned long
52 nilfs_cpfile_checkpoints_in_block(const struct inode *cpfile,
53 __u64 curr,
54 __u64 max)
55 {
56 return min_t(__u64,
57 nilfs_cpfile_checkpoints_per_block(cpfile) -
58 nilfs_cpfile_get_offset(cpfile, curr),
59 max - curr);
60 }
61
62 static inline int nilfs_cpfile_is_in_first(const struct inode *cpfile,
63 __u64 cno)
64 {
65 return nilfs_cpfile_get_blkoff(cpfile, cno) == 0;
66 }
67
68 static unsigned int
69 nilfs_cpfile_block_add_valid_checkpoints(const struct inode *cpfile,
70 struct buffer_head *bh,
71 void *kaddr,
72 unsigned int n)
73 {
74 struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
75 unsigned int count;
76
77 count = le32_to_cpu(cp->cp_checkpoints_count) + n;
78 cp->cp_checkpoints_count = cpu_to_le32(count);
79 return count;
80 }
81
82 static unsigned int
83 nilfs_cpfile_block_sub_valid_checkpoints(const struct inode *cpfile,
84 struct buffer_head *bh,
85 void *kaddr,
86 unsigned int n)
87 {
88 struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
89 unsigned int count;
90
91 WARN_ON(le32_to_cpu(cp->cp_checkpoints_count) < n);
92 count = le32_to_cpu(cp->cp_checkpoints_count) - n;
93 cp->cp_checkpoints_count = cpu_to_le32(count);
94 return count;
95 }
96
97 static inline struct nilfs_cpfile_header *
98 nilfs_cpfile_block_get_header(const struct inode *cpfile,
99 struct buffer_head *bh,
100 void *kaddr)
101 {
102 return kaddr + bh_offset(bh);
103 }
104
105 static struct nilfs_checkpoint *
106 nilfs_cpfile_block_get_checkpoint(const struct inode *cpfile, __u64 cno,
107 struct buffer_head *bh,
108 void *kaddr)
109 {
110 return kaddr + bh_offset(bh) + nilfs_cpfile_get_offset(cpfile, cno) *
111 NILFS_MDT(cpfile)->mi_entry_size;
112 }
113
114 static void nilfs_cpfile_block_init(struct inode *cpfile,
115 struct buffer_head *bh,
116 void *kaddr)
117 {
118 struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
119 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
120 int n = nilfs_cpfile_checkpoints_per_block(cpfile);
121
122 while (n-- > 0) {
123 nilfs_checkpoint_set_invalid(cp);
124 cp = (void *)cp + cpsz;
125 }
126 }
127
128 static inline int nilfs_cpfile_get_header_block(struct inode *cpfile,
129 struct buffer_head **bhp)
130 {
131 return nilfs_mdt_get_block(cpfile, 0, 0, NULL, bhp);
132 }
133
134 static inline int nilfs_cpfile_get_checkpoint_block(struct inode *cpfile,
135 __u64 cno,
136 int create,
137 struct buffer_head **bhp)
138 {
139 return nilfs_mdt_get_block(cpfile,
140 nilfs_cpfile_get_blkoff(cpfile, cno),
141 create, nilfs_cpfile_block_init, bhp);
142 }
143
144 /**
145 * nilfs_cpfile_find_checkpoint_block - find and get a buffer on cpfile
146 * @cpfile: inode of cpfile
147 * @start_cno: start checkpoint number (inclusive)
148 * @end_cno: end checkpoint number (inclusive)
149 * @cnop: place to store the next checkpoint number
150 * @bhp: place to store a pointer to buffer_head struct
151 *
152 * Return Value: On success, it returns 0. On error, the following negative
153 * error code is returned.
154 *
155 * %-ENOMEM - Insufficient memory available.
156 *
157 * %-EIO - I/O error
158 *
159 * %-ENOENT - no block exists in the range.
160 */
161 static int nilfs_cpfile_find_checkpoint_block(struct inode *cpfile,
162 __u64 start_cno, __u64 end_cno,
163 __u64 *cnop,
164 struct buffer_head **bhp)
165 {
166 unsigned long start, end, blkoff;
167 int ret;
168
169 if (unlikely(start_cno > end_cno))
170 return -ENOENT;
171
172 start = nilfs_cpfile_get_blkoff(cpfile, start_cno);
173 end = nilfs_cpfile_get_blkoff(cpfile, end_cno);
174
175 ret = nilfs_mdt_find_block(cpfile, start, end, &blkoff, bhp);
176 if (!ret)
177 *cnop = (blkoff == start) ? start_cno :
178 nilfs_cpfile_first_checkpoint_in_block(cpfile, blkoff);
179 return ret;
180 }
181
182 static inline int nilfs_cpfile_delete_checkpoint_block(struct inode *cpfile,
183 __u64 cno)
184 {
185 return nilfs_mdt_delete_block(cpfile,
186 nilfs_cpfile_get_blkoff(cpfile, cno));
187 }
188
189 /**
190 * nilfs_cpfile_read_checkpoint - read a checkpoint entry in cpfile
191 * @cpfile: checkpoint file inode
192 * @cno: number of checkpoint entry to read
193 * @root: nilfs root object
194 * @ifile: ifile's inode to read and attach to @root
195 *
196 * This function imports checkpoint information from the checkpoint file and
197 * stores it to the inode file given by @ifile and the nilfs root object
198 * given by @root.
199 *
200 * Return: 0 on success, or the following negative error code on failure.
201 * * %-EINVAL - Invalid checkpoint.
202 * * %-ENOMEM - Insufficient memory available.
203 * * %-EIO - I/O error (including metadata corruption).
204 */
205 int nilfs_cpfile_read_checkpoint(struct inode *cpfile, __u64 cno,
206 struct nilfs_root *root, struct inode *ifile)
207 {
208 struct buffer_head *cp_bh;
209 struct nilfs_checkpoint *cp;
210 void *kaddr;
211 int ret;
212
213 if (cno < 1 || cno > nilfs_mdt_cno(cpfile))
214 return -EINVAL;
215
216 down_read(&NILFS_MDT(cpfile)->mi_sem);
217 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
218 if (unlikely(ret < 0)) {
219 if (ret == -ENOENT)
220 ret = -EINVAL;
221 goto out_sem;
222 }
223
224 kaddr = kmap_local_page(cp_bh->b_page);
225 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
226 if (nilfs_checkpoint_invalid(cp)) {
227 ret = -EINVAL;
228 goto put_cp;
229 }
230
231 ret = nilfs_read_inode_common(ifile, &cp->cp_ifile_inode);
232 if (unlikely(ret)) {
233 /*
234 * Since this inode is on a checkpoint entry, treat errors
235 * as metadata corruption.
236 */
237 nilfs_err(cpfile->i_sb,
238 "ifile inode (checkpoint number=%llu) corrupted",
239 (unsigned long long)cno);
240 ret = -EIO;
241 goto put_cp;
242 }
243
244 /* Configure the nilfs root object */
245 atomic64_set(&root->inodes_count, le64_to_cpu(cp->cp_inodes_count));
246 atomic64_set(&root->blocks_count, le64_to_cpu(cp->cp_blocks_count));
247 root->ifile = ifile;
248
249 put_cp:
250 kunmap_local(kaddr);
251 brelse(cp_bh);
252 out_sem:
253 up_read(&NILFS_MDT(cpfile)->mi_sem);
254 return ret;
255 }
256
257 /**
258 * nilfs_cpfile_create_checkpoint - create a checkpoint entry on cpfile
259 * @cpfile: checkpoint file inode
260 * @cno: number of checkpoint to set up
261 *
262 * This function creates a checkpoint with the number specified by @cno on
263 * cpfile. If the specified checkpoint entry already exists due to a past
264 * failure, it will be reused without returning an error.
265 * In either case, the buffer of the block containing the checkpoint entry
266 * and the cpfile inode are made dirty for inclusion in the write log.
267 *
268 * Return: 0 on success, or the following negative error code on failure.
269 * * %-ENOMEM - Insufficient memory available.
270 * * %-EIO - I/O error (including metadata corruption).
271 * * %-EROFS - Read only filesystem
272 */
273 int nilfs_cpfile_create_checkpoint(struct inode *cpfile, __u64 cno)
274 {
275 struct buffer_head *header_bh, *cp_bh;
276 struct nilfs_cpfile_header *header;
277 struct nilfs_checkpoint *cp;
278 void *kaddr;
279 int ret;
280
281 if (WARN_ON_ONCE(cno < 1))
282 return -EIO;
283
284 down_write(&NILFS_MDT(cpfile)->mi_sem);
285 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
286 if (unlikely(ret < 0)) {
287 if (ret == -ENOENT) {
288 nilfs_error(cpfile->i_sb,
289 "checkpoint creation failed due to metadata corruption.");
290 ret = -EIO;
291 }
292 goto out_sem;
293 }
294 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 1, &cp_bh);
295 if (unlikely(ret < 0))
296 goto out_header;
297
298 kaddr = kmap_local_page(cp_bh->b_page);
299 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
300 if (nilfs_checkpoint_invalid(cp)) {
301 /* a newly-created checkpoint */
302 nilfs_checkpoint_clear_invalid(cp);
303 if (!nilfs_cpfile_is_in_first(cpfile, cno))
304 nilfs_cpfile_block_add_valid_checkpoints(cpfile, cp_bh,
305 kaddr, 1);
306 kunmap_local(kaddr);
307
308 kaddr = kmap_local_page(header_bh->b_page);
309 header = nilfs_cpfile_block_get_header(cpfile, header_bh,
310 kaddr);
311 le64_add_cpu(&header->ch_ncheckpoints, 1);
312 kunmap_local(kaddr);
313 mark_buffer_dirty(header_bh);
314 } else {
315 kunmap_local(kaddr);
316 }
317
318 /* Force the buffer and the inode to become dirty */
319 mark_buffer_dirty(cp_bh);
320 brelse(cp_bh);
321 nilfs_mdt_mark_dirty(cpfile);
322
323 out_header:
324 brelse(header_bh);
325
326 out_sem:
327 up_write(&NILFS_MDT(cpfile)->mi_sem);
328 return ret;
329 }
330
331 /**
332 * nilfs_cpfile_finalize_checkpoint - fill in a checkpoint entry in cpfile
333 * @cpfile: checkpoint file inode
334 * @cno: checkpoint number
335 * @root: nilfs root object
336 * @blkinc: number of blocks added by this checkpoint
337 * @ctime: checkpoint creation time
338 * @minor: minor checkpoint flag
339 *
340 * This function completes the checkpoint entry numbered by @cno in the
341 * cpfile with the data given by the arguments @root, @blkinc, @ctime, and
342 * @minor.
343 *
344 * Return: 0 on success, or the following negative error code on failure.
345 * * %-ENOMEM - Insufficient memory available.
346 * * %-EIO - I/O error (including metadata corruption).
347 */
348 int nilfs_cpfile_finalize_checkpoint(struct inode *cpfile, __u64 cno,
349 struct nilfs_root *root, __u64 blkinc,
350 time64_t ctime, bool minor)
351 {
352 struct buffer_head *cp_bh;
353 struct nilfs_checkpoint *cp;
354 void *kaddr;
355 int ret;
356
357 if (WARN_ON_ONCE(cno < 1))
358 return -EIO;
359
360 down_write(&NILFS_MDT(cpfile)->mi_sem);
361 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
362 if (unlikely(ret < 0)) {
363 if (ret == -ENOENT)
364 goto error;
365 goto out_sem;
366 }
367
368 kaddr = kmap_local_page(cp_bh->b_page);
369 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
370 if (unlikely(nilfs_checkpoint_invalid(cp))) {
371 kunmap_local(kaddr);
372 brelse(cp_bh);
373 goto error;
374 }
375
376 cp->cp_snapshot_list.ssl_next = 0;
377 cp->cp_snapshot_list.ssl_prev = 0;
378 cp->cp_inodes_count = cpu_to_le64(atomic64_read(&root->inodes_count));
379 cp->cp_blocks_count = cpu_to_le64(atomic64_read(&root->blocks_count));
380 cp->cp_nblk_inc = cpu_to_le64(blkinc);
381 cp->cp_create = cpu_to_le64(ctime);
382 cp->cp_cno = cpu_to_le64(cno);
383
384 if (minor)
385 nilfs_checkpoint_set_minor(cp);
386 else
387 nilfs_checkpoint_clear_minor(cp);
388
389 nilfs_write_inode_common(root->ifile, &cp->cp_ifile_inode);
390 nilfs_bmap_write(NILFS_I(root->ifile)->i_bmap, &cp->cp_ifile_inode);
391
392 kunmap_local(kaddr);
393 brelse(cp_bh);
394 out_sem:
395 up_write(&NILFS_MDT(cpfile)->mi_sem);
396 return ret;
397
398 error:
399 nilfs_error(cpfile->i_sb,
400 "checkpoint finalization failed due to metadata corruption.");
401 ret = -EIO;
402 goto out_sem;
403 }
404
405 /**
406 * nilfs_cpfile_delete_checkpoints - delete checkpoints
407 * @cpfile: inode of checkpoint file
408 * @start: start checkpoint number
409 * @end: end checkpoint number
410 *
411 * Description: nilfs_cpfile_delete_checkpoints() deletes the checkpoints in
412 * the period from @start to @end, excluding @end itself. The checkpoints
413 * which have been already deleted are ignored.
414 *
415 * Return Value: On success, 0 is returned. On error, one of the following
416 * negative error codes is returned.
417 *
418 * %-EIO - I/O error.
419 *
420 * %-ENOMEM - Insufficient amount of memory available.
421 *
422 * %-EINVAL - invalid checkpoints.
423 */
424 int nilfs_cpfile_delete_checkpoints(struct inode *cpfile,
425 __u64 start,
426 __u64 end)
427 {
428 struct buffer_head *header_bh, *cp_bh;
429 struct nilfs_cpfile_header *header;
430 struct nilfs_checkpoint *cp;
431 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
432 __u64 cno;
433 void *kaddr;
434 unsigned long tnicps;
435 int ret, ncps, nicps, nss, count, i;
436
437 if (unlikely(start == 0 || start > end)) {
438 nilfs_err(cpfile->i_sb,
439 "cannot delete checkpoints: invalid range [%llu, %llu)",
440 (unsigned long long)start, (unsigned long long)end);
441 return -EINVAL;
442 }
443
444 down_write(&NILFS_MDT(cpfile)->mi_sem);
445
446 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
447 if (ret < 0)
448 goto out_sem;
449 tnicps = 0;
450 nss = 0;
451
452 for (cno = start; cno < end; cno += ncps) {
453 ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, end);
454 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
455 if (ret < 0) {
456 if (ret != -ENOENT)
457 break;
458 /* skip hole */
459 ret = 0;
460 continue;
461 }
462
463 kaddr = kmap_local_page(cp_bh->b_page);
464 cp = nilfs_cpfile_block_get_checkpoint(
465 cpfile, cno, cp_bh, kaddr);
466 nicps = 0;
467 for (i = 0; i < ncps; i++, cp = (void *)cp + cpsz) {
468 if (nilfs_checkpoint_snapshot(cp)) {
469 nss++;
470 } else if (!nilfs_checkpoint_invalid(cp)) {
471 nilfs_checkpoint_set_invalid(cp);
472 nicps++;
473 }
474 }
475 if (nicps > 0) {
476 tnicps += nicps;
477 mark_buffer_dirty(cp_bh);
478 nilfs_mdt_mark_dirty(cpfile);
479 if (!nilfs_cpfile_is_in_first(cpfile, cno)) {
480 count =
481 nilfs_cpfile_block_sub_valid_checkpoints(
482 cpfile, cp_bh, kaddr, nicps);
483 if (count == 0) {
484 /* make hole */
485 kunmap_local(kaddr);
486 brelse(cp_bh);
487 ret =
488 nilfs_cpfile_delete_checkpoint_block(
489 cpfile, cno);
490 if (ret == 0)
491 continue;
492 nilfs_err(cpfile->i_sb,
493 "error %d deleting checkpoint block",
494 ret);
495 break;
496 }
497 }
498 }
499
500 kunmap_local(kaddr);
501 brelse(cp_bh);
502 }
503
504 if (tnicps > 0) {
505 kaddr = kmap_local_page(header_bh->b_page);
506 header = nilfs_cpfile_block_get_header(cpfile, header_bh,
507 kaddr);
508 le64_add_cpu(&header->ch_ncheckpoints, -(u64)tnicps);
509 mark_buffer_dirty(header_bh);
510 nilfs_mdt_mark_dirty(cpfile);
511 kunmap_local(kaddr);
512 }
513
514 brelse(header_bh);
515 if (nss > 0)
516 ret = -EBUSY;
517
518 out_sem:
519 up_write(&NILFS_MDT(cpfile)->mi_sem);
520 return ret;
521 }
522
523 static void nilfs_cpfile_checkpoint_to_cpinfo(struct inode *cpfile,
524 struct nilfs_checkpoint *cp,
525 struct nilfs_cpinfo *ci)
526 {
527 ci->ci_flags = le32_to_cpu(cp->cp_flags);
528 ci->ci_cno = le64_to_cpu(cp->cp_cno);
529 ci->ci_create = le64_to_cpu(cp->cp_create);
530 ci->ci_nblk_inc = le64_to_cpu(cp->cp_nblk_inc);
531 ci->ci_inodes_count = le64_to_cpu(cp->cp_inodes_count);
532 ci->ci_blocks_count = le64_to_cpu(cp->cp_blocks_count);
533 ci->ci_next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
534 }
535
536 static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop,
537 void *buf, unsigned int cisz,
538 size_t nci)
539 {
540 struct nilfs_checkpoint *cp;
541 struct nilfs_cpinfo *ci = buf;
542 struct buffer_head *bh;
543 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
544 __u64 cur_cno = nilfs_mdt_cno(cpfile), cno = *cnop;
545 void *kaddr;
546 int n, ret;
547 int ncps, i;
548
549 if (cno == 0)
550 return -ENOENT; /* checkpoint number 0 is invalid */
551 down_read(&NILFS_MDT(cpfile)->mi_sem);
552
553 for (n = 0; n < nci; cno += ncps) {
554 ret = nilfs_cpfile_find_checkpoint_block(
555 cpfile, cno, cur_cno - 1, &cno, &bh);
556 if (ret < 0) {
557 if (likely(ret == -ENOENT))
558 break;
559 goto out;
560 }
561 ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, cur_cno);
562
563 kaddr = kmap_local_page(bh->b_page);
564 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
565 for (i = 0; i < ncps && n < nci; i++, cp = (void *)cp + cpsz) {
566 if (!nilfs_checkpoint_invalid(cp)) {
567 nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp,
568 ci);
569 ci = (void *)ci + cisz;
570 n++;
571 }
572 }
573 kunmap_local(kaddr);
574 brelse(bh);
575 }
576
577 ret = n;
578 if (n > 0) {
579 ci = (void *)ci - cisz;
580 *cnop = ci->ci_cno + 1;
581 }
582
583 out:
584 up_read(&NILFS_MDT(cpfile)->mi_sem);
585 return ret;
586 }
587
588 static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
589 void *buf, unsigned int cisz,
590 size_t nci)
591 {
592 struct buffer_head *bh;
593 struct nilfs_cpfile_header *header;
594 struct nilfs_checkpoint *cp;
595 struct nilfs_cpinfo *ci = buf;
596 __u64 curr = *cnop, next;
597 unsigned long curr_blkoff, next_blkoff;
598 void *kaddr;
599 int n = 0, ret;
600
601 down_read(&NILFS_MDT(cpfile)->mi_sem);
602
603 if (curr == 0) {
604 ret = nilfs_cpfile_get_header_block(cpfile, &bh);
605 if (ret < 0)
606 goto out;
607 kaddr = kmap_local_page(bh->b_page);
608 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
609 curr = le64_to_cpu(header->ch_snapshot_list.ssl_next);
610 kunmap_local(kaddr);
611 brelse(bh);
612 if (curr == 0) {
613 ret = 0;
614 goto out;
615 }
616 } else if (unlikely(curr == ~(__u64)0)) {
617 ret = 0;
618 goto out;
619 }
620
621 curr_blkoff = nilfs_cpfile_get_blkoff(cpfile, curr);
622 ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr, 0, &bh);
623 if (unlikely(ret < 0)) {
624 if (ret == -ENOENT)
625 ret = 0; /* No snapshots (started from a hole block) */
626 goto out;
627 }
628 kaddr = kmap_local_page(bh->b_page);
629 while (n < nci) {
630 cp = nilfs_cpfile_block_get_checkpoint(cpfile, curr, bh, kaddr);
631 curr = ~(__u64)0; /* Terminator */
632 if (unlikely(nilfs_checkpoint_invalid(cp) ||
633 !nilfs_checkpoint_snapshot(cp)))
634 break;
635 nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, ci);
636 ci = (void *)ci + cisz;
637 n++;
638 next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
639 if (next == 0)
640 break; /* reach end of the snapshot list */
641
642 next_blkoff = nilfs_cpfile_get_blkoff(cpfile, next);
643 if (curr_blkoff != next_blkoff) {
644 kunmap_local(kaddr);
645 brelse(bh);
646 ret = nilfs_cpfile_get_checkpoint_block(cpfile, next,
647 0, &bh);
648 if (unlikely(ret < 0)) {
649 WARN_ON(ret == -ENOENT);
650 goto out;
651 }
652 kaddr = kmap_local_page(bh->b_page);
653 }
654 curr = next;
655 curr_blkoff = next_blkoff;
656 }
657 kunmap_local(kaddr);
658 brelse(bh);
659 *cnop = curr;
660 ret = n;
661
662 out:
663 up_read(&NILFS_MDT(cpfile)->mi_sem);
664 return ret;
665 }
666
667 /**
668 * nilfs_cpfile_get_cpinfo - get information on checkpoints
669 * @cpfile: checkpoint file inode
670 * @cnop: place to pass a starting checkpoint number and receive a
671 * checkpoint number to continue the search
672 * @mode: mode of checkpoints that the caller wants to retrieve
673 * @buf: buffer for storing checkpoints' information
674 * @cisz: byte size of one checkpoint info item in array
675 * @nci: number of checkpoint info items to retrieve
676 *
677 * nilfs_cpfile_get_cpinfo() searches for checkpoints in @mode state
678 * starting from the checkpoint number stored in @cnop, and stores
679 * information about found checkpoints in @buf.
680 * The buffer pointed to by @buf must be large enough to store information
681 * for @nci checkpoints. If at least one checkpoint information is
682 * successfully retrieved, @cnop is updated to point to the checkpoint
683 * number to continue searching.
684 *
685 * Return: Count of checkpoint info items stored in the output buffer on
686 * success, or the following negative error code on failure.
687 * * %-EINVAL - Invalid checkpoint mode.
688 * * %-ENOMEM - Insufficient memory available.
689 * * %-EIO - I/O error (including metadata corruption).
690 * * %-ENOENT - Invalid checkpoint number specified.
691 */
692
693 ssize_t nilfs_cpfile_get_cpinfo(struct inode *cpfile, __u64 *cnop, int mode,
694 void *buf, unsigned int cisz, size_t nci)
695 {
696 switch (mode) {
697 case NILFS_CHECKPOINT:
698 return nilfs_cpfile_do_get_cpinfo(cpfile, cnop, buf, cisz, nci);
699 case NILFS_SNAPSHOT:
700 return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, buf, cisz, nci);
701 default:
702 return -EINVAL;
703 }
704 }
705
706 /**
707 * nilfs_cpfile_delete_checkpoint -
708 * @cpfile:
709 * @cno:
710 */
711 int nilfs_cpfile_delete_checkpoint(struct inode *cpfile, __u64 cno)
712 {
713 struct nilfs_cpinfo ci;
714 __u64 tcno = cno;
715 ssize_t nci;
716
717 nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, sizeof(ci), 1);
718 if (nci < 0)
719 return nci;
720 else if (nci == 0 || ci.ci_cno != cno)
721 return -ENOENT;
722 else if (nilfs_cpinfo_snapshot(&ci))
723 return -EBUSY;
724
725 return nilfs_cpfile_delete_checkpoints(cpfile, cno, cno + 1);
726 }
727
728 static struct nilfs_snapshot_list *
729 nilfs_cpfile_block_get_snapshot_list(const struct inode *cpfile,
730 __u64 cno,
731 struct buffer_head *bh,
732 void *kaddr)
733 {
734 struct nilfs_cpfile_header *header;
735 struct nilfs_checkpoint *cp;
736 struct nilfs_snapshot_list *list;
737
738 if (cno != 0) {
739 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
740 list = &cp->cp_snapshot_list;
741 } else {
742 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
743 list = &header->ch_snapshot_list;
744 }
745 return list;
746 }
747
748 static int nilfs_cpfile_set_snapshot(struct inode *cpfile, __u64 cno)
749 {
750 struct buffer_head *header_bh, *curr_bh, *prev_bh, *cp_bh;
751 struct nilfs_cpfile_header *header;
752 struct nilfs_checkpoint *cp;
753 struct nilfs_snapshot_list *list;
754 __u64 curr, prev;
755 unsigned long curr_blkoff, prev_blkoff;
756 void *kaddr;
757 int ret;
758
759 if (cno == 0)
760 return -ENOENT; /* checkpoint number 0 is invalid */
761 down_write(&NILFS_MDT(cpfile)->mi_sem);
762
763 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
764 if (ret < 0)
765 goto out_sem;
766 kaddr = kmap_local_page(cp_bh->b_page);
767 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
768 if (nilfs_checkpoint_invalid(cp)) {
769 ret = -ENOENT;
770 kunmap_local(kaddr);
771 goto out_cp;
772 }
773 if (nilfs_checkpoint_snapshot(cp)) {
774 ret = 0;
775 kunmap_local(kaddr);
776 goto out_cp;
777 }
778 kunmap_local(kaddr);
779
780 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
781 if (ret < 0)
782 goto out_cp;
783 kaddr = kmap_local_page(header_bh->b_page);
784 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
785 list = &header->ch_snapshot_list;
786 curr_bh = header_bh;
787 get_bh(curr_bh);
788 curr = 0;
789 curr_blkoff = 0;
790 prev = le64_to_cpu(list->ssl_prev);
791 while (prev > cno) {
792 prev_blkoff = nilfs_cpfile_get_blkoff(cpfile, prev);
793 curr = prev;
794 if (curr_blkoff != prev_blkoff) {
795 kunmap_local(kaddr);
796 brelse(curr_bh);
797 ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr,
798 0, &curr_bh);
799 if (ret < 0)
800 goto out_header;
801 kaddr = kmap_local_page(curr_bh->b_page);
802 }
803 curr_blkoff = prev_blkoff;
804 cp = nilfs_cpfile_block_get_checkpoint(
805 cpfile, curr, curr_bh, kaddr);
806 list = &cp->cp_snapshot_list;
807 prev = le64_to_cpu(list->ssl_prev);
808 }
809 kunmap_local(kaddr);
810
811 if (prev != 0) {
812 ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
813 &prev_bh);
814 if (ret < 0)
815 goto out_curr;
816 } else {
817 prev_bh = header_bh;
818 get_bh(prev_bh);
819 }
820
821 kaddr = kmap_local_page(curr_bh->b_page);
822 list = nilfs_cpfile_block_get_snapshot_list(
823 cpfile, curr, curr_bh, kaddr);
824 list->ssl_prev = cpu_to_le64(cno);
825 kunmap_local(kaddr);
826
827 kaddr = kmap_local_page(cp_bh->b_page);
828 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
829 cp->cp_snapshot_list.ssl_next = cpu_to_le64(curr);
830 cp->cp_snapshot_list.ssl_prev = cpu_to_le64(prev);
831 nilfs_checkpoint_set_snapshot(cp);
832 kunmap_local(kaddr);
833
834 kaddr = kmap_local_page(prev_bh->b_page);
835 list = nilfs_cpfile_block_get_snapshot_list(
836 cpfile, prev, prev_bh, kaddr);
837 list->ssl_next = cpu_to_le64(cno);
838 kunmap_local(kaddr);
839
840 kaddr = kmap_local_page(header_bh->b_page);
841 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
842 le64_add_cpu(&header->ch_nsnapshots, 1);
843 kunmap_local(kaddr);
844
845 mark_buffer_dirty(prev_bh);
846 mark_buffer_dirty(curr_bh);
847 mark_buffer_dirty(cp_bh);
848 mark_buffer_dirty(header_bh);
849 nilfs_mdt_mark_dirty(cpfile);
850
851 brelse(prev_bh);
852
853 out_curr:
854 brelse(curr_bh);
855
856 out_header:
857 brelse(header_bh);
858
859 out_cp:
860 brelse(cp_bh);
861
862 out_sem:
863 up_write(&NILFS_MDT(cpfile)->mi_sem);
864 return ret;
865 }
866
867 static int nilfs_cpfile_clear_snapshot(struct inode *cpfile, __u64 cno)
868 {
869 struct buffer_head *header_bh, *next_bh, *prev_bh, *cp_bh;
870 struct nilfs_cpfile_header *header;
871 struct nilfs_checkpoint *cp;
872 struct nilfs_snapshot_list *list;
873 __u64 next, prev;
874 void *kaddr;
875 int ret;
876
877 if (cno == 0)
878 return -ENOENT; /* checkpoint number 0 is invalid */
879 down_write(&NILFS_MDT(cpfile)->mi_sem);
880
881 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
882 if (ret < 0)
883 goto out_sem;
884 kaddr = kmap_local_page(cp_bh->b_page);
885 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
886 if (nilfs_checkpoint_invalid(cp)) {
887 ret = -ENOENT;
888 kunmap_local(kaddr);
889 goto out_cp;
890 }
891 if (!nilfs_checkpoint_snapshot(cp)) {
892 ret = 0;
893 kunmap_local(kaddr);
894 goto out_cp;
895 }
896
897 list = &cp->cp_snapshot_list;
898 next = le64_to_cpu(list->ssl_next);
899 prev = le64_to_cpu(list->ssl_prev);
900 kunmap_local(kaddr);
901
902 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
903 if (ret < 0)
904 goto out_cp;
905 if (next != 0) {
906 ret = nilfs_cpfile_get_checkpoint_block(cpfile, next, 0,
907 &next_bh);
908 if (ret < 0)
909 goto out_header;
910 } else {
911 next_bh = header_bh;
912 get_bh(next_bh);
913 }
914 if (prev != 0) {
915 ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
916 &prev_bh);
917 if (ret < 0)
918 goto out_next;
919 } else {
920 prev_bh = header_bh;
921 get_bh(prev_bh);
922 }
923
924 kaddr = kmap_local_page(next_bh->b_page);
925 list = nilfs_cpfile_block_get_snapshot_list(
926 cpfile, next, next_bh, kaddr);
927 list->ssl_prev = cpu_to_le64(prev);
928 kunmap_local(kaddr);
929
930 kaddr = kmap_local_page(prev_bh->b_page);
931 list = nilfs_cpfile_block_get_snapshot_list(
932 cpfile, prev, prev_bh, kaddr);
933 list->ssl_next = cpu_to_le64(next);
934 kunmap_local(kaddr);
935
936 kaddr = kmap_local_page(cp_bh->b_page);
937 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
938 cp->cp_snapshot_list.ssl_next = cpu_to_le64(0);
939 cp->cp_snapshot_list.ssl_prev = cpu_to_le64(0);
940 nilfs_checkpoint_clear_snapshot(cp);
941 kunmap_local(kaddr);
942
943 kaddr = kmap_local_page(header_bh->b_page);
944 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
945 le64_add_cpu(&header->ch_nsnapshots, -1);
946 kunmap_local(kaddr);
947
948 mark_buffer_dirty(next_bh);
949 mark_buffer_dirty(prev_bh);
950 mark_buffer_dirty(cp_bh);
951 mark_buffer_dirty(header_bh);
952 nilfs_mdt_mark_dirty(cpfile);
953
954 brelse(prev_bh);
955
956 out_next:
957 brelse(next_bh);
958
959 out_header:
960 brelse(header_bh);
961
962 out_cp:
963 brelse(cp_bh);
964
965 out_sem:
966 up_write(&NILFS_MDT(cpfile)->mi_sem);
967 return ret;
968 }
969
970 /**
971 * nilfs_cpfile_is_snapshot -
972 * @cpfile: inode of checkpoint file
973 * @cno: checkpoint number
974 *
975 * Description:
976 *
977 * Return Value: On success, 1 is returned if the checkpoint specified by
978 * @cno is a snapshot, or 0 if not. On error, one of the following negative
979 * error codes is returned.
980 *
981 * %-EIO - I/O error.
982 *
983 * %-ENOMEM - Insufficient amount of memory available.
984 *
985 * %-ENOENT - No such checkpoint.
986 */
987 int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
988 {
989 struct buffer_head *bh;
990 struct nilfs_checkpoint *cp;
991 void *kaddr;
992 int ret;
993
994 /*
995 * CP number is invalid if it's zero or larger than the
996 * largest existing one.
997 */
998 if (cno == 0 || cno >= nilfs_mdt_cno(cpfile))
999 return -ENOENT;
1000 down_read(&NILFS_MDT(cpfile)->mi_sem);
1001
1002 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
1003 if (ret < 0)
1004 goto out;
1005 kaddr = kmap_local_page(bh->b_page);
1006 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
1007 if (nilfs_checkpoint_invalid(cp))
1008 ret = -ENOENT;
1009 else
1010 ret = nilfs_checkpoint_snapshot(cp);
1011 kunmap_local(kaddr);
1012 brelse(bh);
1013
1014 out:
1015 up_read(&NILFS_MDT(cpfile)->mi_sem);
1016 return ret;
1017 }
1018
1019 /**
1020 * nilfs_cpfile_change_cpmode - change checkpoint mode
1021 * @cpfile: inode of checkpoint file
1022 * @cno: checkpoint number
1023 * @mode: mode of checkpoint
1024 *
1025 * Description: nilfs_change_cpmode() changes the mode of the checkpoint
1026 * specified by @cno. The mode @mode is NILFS_CHECKPOINT or NILFS_SNAPSHOT.
1027 *
1028 * Return Value: On success, 0 is returned. On error, one of the following
1029 * negative error codes is returned.
1030 *
1031 * %-EIO - I/O error.
1032 *
1033 * %-ENOMEM - Insufficient amount of memory available.
1034 *
1035 * %-ENOENT - No such checkpoint.
1036 */
1037 int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode)
1038 {
1039 int ret;
1040
1041 switch (mode) {
1042 case NILFS_CHECKPOINT:
1043 if (nilfs_checkpoint_is_mounted(cpfile->i_sb, cno))
1044 /*
1045 * Current implementation does not have to protect
1046 * plain read-only mounts since they are exclusive
1047 * with a read/write mount and are protected from the
1048 * cleaner.
1049 */
1050 ret = -EBUSY;
1051 else
1052 ret = nilfs_cpfile_clear_snapshot(cpfile, cno);
1053 return ret;
1054 case NILFS_SNAPSHOT:
1055 return nilfs_cpfile_set_snapshot(cpfile, cno);
1056 default:
1057 return -EINVAL;
1058 }
1059 }
1060
1061 /**
1062 * nilfs_cpfile_get_stat - get checkpoint statistics
1063 * @cpfile: inode of checkpoint file
1064 * @cpstat: pointer to a structure of checkpoint statistics
1065 *
1066 * Description: nilfs_cpfile_get_stat() returns information about checkpoints.
1067 *
1068 * Return Value: On success, 0 is returned, and checkpoints information is
1069 * stored in the place pointed by @cpstat. On error, one of the following
1070 * negative error codes is returned.
1071 *
1072 * %-EIO - I/O error.
1073 *
1074 * %-ENOMEM - Insufficient amount of memory available.
1075 */
1076 int nilfs_cpfile_get_stat(struct inode *cpfile, struct nilfs_cpstat *cpstat)
1077 {
1078 struct buffer_head *bh;
1079 struct nilfs_cpfile_header *header;
1080 void *kaddr;
1081 int ret;
1082
1083 down_read(&NILFS_MDT(cpfile)->mi_sem);
1084
1085 ret = nilfs_cpfile_get_header_block(cpfile, &bh);
1086 if (ret < 0)
1087 goto out_sem;
1088 kaddr = kmap_local_page(bh->b_page);
1089 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
1090 cpstat->cs_cno = nilfs_mdt_cno(cpfile);
1091 cpstat->cs_ncps = le64_to_cpu(header->ch_ncheckpoints);
1092 cpstat->cs_nsss = le64_to_cpu(header->ch_nsnapshots);
1093 kunmap_local(kaddr);
1094 brelse(bh);
1095
1096 out_sem:
1097 up_read(&NILFS_MDT(cpfile)->mi_sem);
1098 return ret;
1099 }
1100
1101 /**
1102 * nilfs_cpfile_read - read or get cpfile inode
1103 * @sb: super block instance
1104 * @cpsize: size of a checkpoint entry
1105 * @raw_inode: on-disk cpfile inode
1106 * @inodep: buffer to store the inode
1107 */
1108 int nilfs_cpfile_read(struct super_block *sb, size_t cpsize,
1109 struct nilfs_inode *raw_inode, struct inode **inodep)
1110 {
1111 struct inode *cpfile;
1112 int err;
1113
1114 if (cpsize > sb->s_blocksize) {
1115 nilfs_err(sb, "too large checkpoint size: %zu bytes", cpsize);
1116 return -EINVAL;
1117 } else if (cpsize < NILFS_MIN_CHECKPOINT_SIZE) {
1118 nilfs_err(sb, "too small checkpoint size: %zu bytes", cpsize);
1119 return -EINVAL;
1120 }
1121
1122 cpfile = nilfs_iget_locked(sb, NULL, NILFS_CPFILE_INO);
1123 if (unlikely(!cpfile))
1124 return -ENOMEM;
1125 if (!(cpfile->i_state & I_NEW))
1126 goto out;
1127
1128 err = nilfs_mdt_init(cpfile, NILFS_MDT_GFP, 0);
1129 if (err)
1130 goto failed;
1131
1132 nilfs_mdt_set_entry_size(cpfile, cpsize,
1133 sizeof(struct nilfs_cpfile_header));
1134
1135 err = nilfs_read_inode_common(cpfile, raw_inode);
1136 if (err)
1137 goto failed;
1138
1139 unlock_new_inode(cpfile);
1140 out:
1141 *inodep = cpfile;
1142 return 0;
1143 failed:
1144 iget_failed(cpfile);
1145 return err;
1146 }
1147
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