Loading...
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
19static inline unsigned long
20nilfs_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 */
26static unsigned long
27nilfs_cpfile_get_blkoff(const struct inode *cpfile, __u64 cno)
28{
29 __u64 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
30
31 do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile));
32 return (unsigned long)tcno;
33}
34
35/* offset in block */
36static unsigned long
37nilfs_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
44static __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
51static unsigned long
52nilfs_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
62static 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
68static unsigned int
69nilfs_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
82static unsigned int
83nilfs_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
97static inline struct nilfs_cpfile_header *
98nilfs_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
105static struct nilfs_checkpoint *
106nilfs_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
114static 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
128static 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
134static 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 */
161static 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
182static 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_get_checkpoint - get a checkpoint
191 * @cpfile: inode of checkpoint file
192 * @cno: checkpoint number
193 * @create: create flag
194 * @cpp: pointer to a checkpoint
195 * @bhp: pointer to a buffer head
196 *
197 * Description: nilfs_cpfile_get_checkpoint() acquires the checkpoint
198 * specified by @cno. A new checkpoint will be created if @cno is the current
199 * checkpoint number and @create is nonzero.
200 *
201 * Return Value: On success, 0 is returned, and the checkpoint and the
202 * buffer head of the buffer on which the checkpoint is located are stored in
203 * the place pointed by @cpp and @bhp, respectively. On error, one of the
204 * following negative error codes is returned.
205 *
206 * %-EIO - I/O error.
207 *
208 * %-ENOMEM - Insufficient amount of memory available.
209 *
210 * %-ENOENT - No such checkpoint.
211 *
212 * %-EINVAL - invalid checkpoint.
213 */
214int nilfs_cpfile_get_checkpoint(struct inode *cpfile,
215 __u64 cno,
216 int create,
217 struct nilfs_checkpoint **cpp,
218 struct buffer_head **bhp)
219{
220 struct buffer_head *header_bh, *cp_bh;
221 struct nilfs_cpfile_header *header;
222 struct nilfs_checkpoint *cp;
223 void *kaddr;
224 int ret;
225
226 if (unlikely(cno < 1 || cno > nilfs_mdt_cno(cpfile) ||
227 (cno < nilfs_mdt_cno(cpfile) && create)))
228 return -EINVAL;
229
230 down_write(&NILFS_MDT(cpfile)->mi_sem);
231
232 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
233 if (ret < 0)
234 goto out_sem;
235 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, create, &cp_bh);
236 if (ret < 0)
237 goto out_header;
238 kaddr = kmap(cp_bh->b_page);
239 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
240 if (nilfs_checkpoint_invalid(cp)) {
241 if (!create) {
242 kunmap(cp_bh->b_page);
243 brelse(cp_bh);
244 ret = -ENOENT;
245 goto out_header;
246 }
247 /* a newly-created checkpoint */
248 nilfs_checkpoint_clear_invalid(cp);
249 if (!nilfs_cpfile_is_in_first(cpfile, cno))
250 nilfs_cpfile_block_add_valid_checkpoints(cpfile, cp_bh,
251 kaddr, 1);
252 mark_buffer_dirty(cp_bh);
253
254 kaddr = kmap_atomic(header_bh->b_page);
255 header = nilfs_cpfile_block_get_header(cpfile, header_bh,
256 kaddr);
257 le64_add_cpu(&header->ch_ncheckpoints, 1);
258 kunmap_atomic(kaddr);
259 mark_buffer_dirty(header_bh);
260 nilfs_mdt_mark_dirty(cpfile);
261 }
262
263 if (cpp != NULL)
264 *cpp = cp;
265 *bhp = cp_bh;
266
267 out_header:
268 brelse(header_bh);
269
270 out_sem:
271 up_write(&NILFS_MDT(cpfile)->mi_sem);
272 return ret;
273}
274
275/**
276 * nilfs_cpfile_put_checkpoint - put a checkpoint
277 * @cpfile: inode of checkpoint file
278 * @cno: checkpoint number
279 * @bh: buffer head
280 *
281 * Description: nilfs_cpfile_put_checkpoint() releases the checkpoint
282 * specified by @cno. @bh must be the buffer head which has been returned by
283 * a previous call to nilfs_cpfile_get_checkpoint() with @cno.
284 */
285void nilfs_cpfile_put_checkpoint(struct inode *cpfile, __u64 cno,
286 struct buffer_head *bh)
287{
288 kunmap(bh->b_page);
289 brelse(bh);
290}
291
292/**
293 * nilfs_cpfile_delete_checkpoints - delete checkpoints
294 * @cpfile: inode of checkpoint file
295 * @start: start checkpoint number
296 * @end: end checkpoint number
297 *
298 * Description: nilfs_cpfile_delete_checkpoints() deletes the checkpoints in
299 * the period from @start to @end, excluding @end itself. The checkpoints
300 * which have been already deleted are ignored.
301 *
302 * Return Value: On success, 0 is returned. On error, one of the following
303 * negative error codes is returned.
304 *
305 * %-EIO - I/O error.
306 *
307 * %-ENOMEM - Insufficient amount of memory available.
308 *
309 * %-EINVAL - invalid checkpoints.
310 */
311int nilfs_cpfile_delete_checkpoints(struct inode *cpfile,
312 __u64 start,
313 __u64 end)
314{
315 struct buffer_head *header_bh, *cp_bh;
316 struct nilfs_cpfile_header *header;
317 struct nilfs_checkpoint *cp;
318 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
319 __u64 cno;
320 void *kaddr;
321 unsigned long tnicps;
322 int ret, ncps, nicps, nss, count, i;
323
324 if (unlikely(start == 0 || start > end)) {
325 nilfs_err(cpfile->i_sb,
326 "cannot delete checkpoints: invalid range [%llu, %llu)",
327 (unsigned long long)start, (unsigned long long)end);
328 return -EINVAL;
329 }
330
331 down_write(&NILFS_MDT(cpfile)->mi_sem);
332
333 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
334 if (ret < 0)
335 goto out_sem;
336 tnicps = 0;
337 nss = 0;
338
339 for (cno = start; cno < end; cno += ncps) {
340 ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, end);
341 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
342 if (ret < 0) {
343 if (ret != -ENOENT)
344 break;
345 /* skip hole */
346 ret = 0;
347 continue;
348 }
349
350 kaddr = kmap_atomic(cp_bh->b_page);
351 cp = nilfs_cpfile_block_get_checkpoint(
352 cpfile, cno, cp_bh, kaddr);
353 nicps = 0;
354 for (i = 0; i < ncps; i++, cp = (void *)cp + cpsz) {
355 if (nilfs_checkpoint_snapshot(cp)) {
356 nss++;
357 } else if (!nilfs_checkpoint_invalid(cp)) {
358 nilfs_checkpoint_set_invalid(cp);
359 nicps++;
360 }
361 }
362 if (nicps > 0) {
363 tnicps += nicps;
364 mark_buffer_dirty(cp_bh);
365 nilfs_mdt_mark_dirty(cpfile);
366 if (!nilfs_cpfile_is_in_first(cpfile, cno)) {
367 count =
368 nilfs_cpfile_block_sub_valid_checkpoints(
369 cpfile, cp_bh, kaddr, nicps);
370 if (count == 0) {
371 /* make hole */
372 kunmap_atomic(kaddr);
373 brelse(cp_bh);
374 ret =
375 nilfs_cpfile_delete_checkpoint_block(
376 cpfile, cno);
377 if (ret == 0)
378 continue;
379 nilfs_err(cpfile->i_sb,
380 "error %d deleting checkpoint block",
381 ret);
382 break;
383 }
384 }
385 }
386
387 kunmap_atomic(kaddr);
388 brelse(cp_bh);
389 }
390
391 if (tnicps > 0) {
392 kaddr = kmap_atomic(header_bh->b_page);
393 header = nilfs_cpfile_block_get_header(cpfile, header_bh,
394 kaddr);
395 le64_add_cpu(&header->ch_ncheckpoints, -(u64)tnicps);
396 mark_buffer_dirty(header_bh);
397 nilfs_mdt_mark_dirty(cpfile);
398 kunmap_atomic(kaddr);
399 }
400
401 brelse(header_bh);
402 if (nss > 0)
403 ret = -EBUSY;
404
405 out_sem:
406 up_write(&NILFS_MDT(cpfile)->mi_sem);
407 return ret;
408}
409
410static void nilfs_cpfile_checkpoint_to_cpinfo(struct inode *cpfile,
411 struct nilfs_checkpoint *cp,
412 struct nilfs_cpinfo *ci)
413{
414 ci->ci_flags = le32_to_cpu(cp->cp_flags);
415 ci->ci_cno = le64_to_cpu(cp->cp_cno);
416 ci->ci_create = le64_to_cpu(cp->cp_create);
417 ci->ci_nblk_inc = le64_to_cpu(cp->cp_nblk_inc);
418 ci->ci_inodes_count = le64_to_cpu(cp->cp_inodes_count);
419 ci->ci_blocks_count = le64_to_cpu(cp->cp_blocks_count);
420 ci->ci_next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
421}
422
423static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop,
424 void *buf, unsigned int cisz,
425 size_t nci)
426{
427 struct nilfs_checkpoint *cp;
428 struct nilfs_cpinfo *ci = buf;
429 struct buffer_head *bh;
430 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
431 __u64 cur_cno = nilfs_mdt_cno(cpfile), cno = *cnop;
432 void *kaddr;
433 int n, ret;
434 int ncps, i;
435
436 if (cno == 0)
437 return -ENOENT; /* checkpoint number 0 is invalid */
438 down_read(&NILFS_MDT(cpfile)->mi_sem);
439
440 for (n = 0; n < nci; cno += ncps) {
441 ret = nilfs_cpfile_find_checkpoint_block(
442 cpfile, cno, cur_cno - 1, &cno, &bh);
443 if (ret < 0) {
444 if (likely(ret == -ENOENT))
445 break;
446 goto out;
447 }
448 ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, cur_cno);
449
450 kaddr = kmap_atomic(bh->b_page);
451 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
452 for (i = 0; i < ncps && n < nci; i++, cp = (void *)cp + cpsz) {
453 if (!nilfs_checkpoint_invalid(cp)) {
454 nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp,
455 ci);
456 ci = (void *)ci + cisz;
457 n++;
458 }
459 }
460 kunmap_atomic(kaddr);
461 brelse(bh);
462 }
463
464 ret = n;
465 if (n > 0) {
466 ci = (void *)ci - cisz;
467 *cnop = ci->ci_cno + 1;
468 }
469
470 out:
471 up_read(&NILFS_MDT(cpfile)->mi_sem);
472 return ret;
473}
474
475static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
476 void *buf, unsigned int cisz,
477 size_t nci)
478{
479 struct buffer_head *bh;
480 struct nilfs_cpfile_header *header;
481 struct nilfs_checkpoint *cp;
482 struct nilfs_cpinfo *ci = buf;
483 __u64 curr = *cnop, next;
484 unsigned long curr_blkoff, next_blkoff;
485 void *kaddr;
486 int n = 0, ret;
487
488 down_read(&NILFS_MDT(cpfile)->mi_sem);
489
490 if (curr == 0) {
491 ret = nilfs_cpfile_get_header_block(cpfile, &bh);
492 if (ret < 0)
493 goto out;
494 kaddr = kmap_atomic(bh->b_page);
495 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
496 curr = le64_to_cpu(header->ch_snapshot_list.ssl_next);
497 kunmap_atomic(kaddr);
498 brelse(bh);
499 if (curr == 0) {
500 ret = 0;
501 goto out;
502 }
503 } else if (unlikely(curr == ~(__u64)0)) {
504 ret = 0;
505 goto out;
506 }
507
508 curr_blkoff = nilfs_cpfile_get_blkoff(cpfile, curr);
509 ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr, 0, &bh);
510 if (unlikely(ret < 0)) {
511 if (ret == -ENOENT)
512 ret = 0; /* No snapshots (started from a hole block) */
513 goto out;
514 }
515 kaddr = kmap_atomic(bh->b_page);
516 while (n < nci) {
517 cp = nilfs_cpfile_block_get_checkpoint(cpfile, curr, bh, kaddr);
518 curr = ~(__u64)0; /* Terminator */
519 if (unlikely(nilfs_checkpoint_invalid(cp) ||
520 !nilfs_checkpoint_snapshot(cp)))
521 break;
522 nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, ci);
523 ci = (void *)ci + cisz;
524 n++;
525 next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
526 if (next == 0)
527 break; /* reach end of the snapshot list */
528
529 next_blkoff = nilfs_cpfile_get_blkoff(cpfile, next);
530 if (curr_blkoff != next_blkoff) {
531 kunmap_atomic(kaddr);
532 brelse(bh);
533 ret = nilfs_cpfile_get_checkpoint_block(cpfile, next,
534 0, &bh);
535 if (unlikely(ret < 0)) {
536 WARN_ON(ret == -ENOENT);
537 goto out;
538 }
539 kaddr = kmap_atomic(bh->b_page);
540 }
541 curr = next;
542 curr_blkoff = next_blkoff;
543 }
544 kunmap_atomic(kaddr);
545 brelse(bh);
546 *cnop = curr;
547 ret = n;
548
549 out:
550 up_read(&NILFS_MDT(cpfile)->mi_sem);
551 return ret;
552}
553
554/**
555 * nilfs_cpfile_get_cpinfo -
556 * @cpfile:
557 * @cno:
558 * @ci:
559 * @nci:
560 */
561
562ssize_t nilfs_cpfile_get_cpinfo(struct inode *cpfile, __u64 *cnop, int mode,
563 void *buf, unsigned int cisz, size_t nci)
564{
565 switch (mode) {
566 case NILFS_CHECKPOINT:
567 return nilfs_cpfile_do_get_cpinfo(cpfile, cnop, buf, cisz, nci);
568 case NILFS_SNAPSHOT:
569 return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, buf, cisz, nci);
570 default:
571 return -EINVAL;
572 }
573}
574
575/**
576 * nilfs_cpfile_delete_checkpoint -
577 * @cpfile:
578 * @cno:
579 */
580int nilfs_cpfile_delete_checkpoint(struct inode *cpfile, __u64 cno)
581{
582 struct nilfs_cpinfo ci;
583 __u64 tcno = cno;
584 ssize_t nci;
585
586 nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, sizeof(ci), 1);
587 if (nci < 0)
588 return nci;
589 else if (nci == 0 || ci.ci_cno != cno)
590 return -ENOENT;
591 else if (nilfs_cpinfo_snapshot(&ci))
592 return -EBUSY;
593
594 return nilfs_cpfile_delete_checkpoints(cpfile, cno, cno + 1);
595}
596
597static struct nilfs_snapshot_list *
598nilfs_cpfile_block_get_snapshot_list(const struct inode *cpfile,
599 __u64 cno,
600 struct buffer_head *bh,
601 void *kaddr)
602{
603 struct nilfs_cpfile_header *header;
604 struct nilfs_checkpoint *cp;
605 struct nilfs_snapshot_list *list;
606
607 if (cno != 0) {
608 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
609 list = &cp->cp_snapshot_list;
610 } else {
611 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
612 list = &header->ch_snapshot_list;
613 }
614 return list;
615}
616
617static int nilfs_cpfile_set_snapshot(struct inode *cpfile, __u64 cno)
618{
619 struct buffer_head *header_bh, *curr_bh, *prev_bh, *cp_bh;
620 struct nilfs_cpfile_header *header;
621 struct nilfs_checkpoint *cp;
622 struct nilfs_snapshot_list *list;
623 __u64 curr, prev;
624 unsigned long curr_blkoff, prev_blkoff;
625 void *kaddr;
626 int ret;
627
628 if (cno == 0)
629 return -ENOENT; /* checkpoint number 0 is invalid */
630 down_write(&NILFS_MDT(cpfile)->mi_sem);
631
632 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
633 if (ret < 0)
634 goto out_sem;
635 kaddr = kmap_atomic(cp_bh->b_page);
636 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
637 if (nilfs_checkpoint_invalid(cp)) {
638 ret = -ENOENT;
639 kunmap_atomic(kaddr);
640 goto out_cp;
641 }
642 if (nilfs_checkpoint_snapshot(cp)) {
643 ret = 0;
644 kunmap_atomic(kaddr);
645 goto out_cp;
646 }
647 kunmap_atomic(kaddr);
648
649 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
650 if (ret < 0)
651 goto out_cp;
652 kaddr = kmap_atomic(header_bh->b_page);
653 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
654 list = &header->ch_snapshot_list;
655 curr_bh = header_bh;
656 get_bh(curr_bh);
657 curr = 0;
658 curr_blkoff = 0;
659 prev = le64_to_cpu(list->ssl_prev);
660 while (prev > cno) {
661 prev_blkoff = nilfs_cpfile_get_blkoff(cpfile, prev);
662 curr = prev;
663 if (curr_blkoff != prev_blkoff) {
664 kunmap_atomic(kaddr);
665 brelse(curr_bh);
666 ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr,
667 0, &curr_bh);
668 if (ret < 0)
669 goto out_header;
670 kaddr = kmap_atomic(curr_bh->b_page);
671 }
672 curr_blkoff = prev_blkoff;
673 cp = nilfs_cpfile_block_get_checkpoint(
674 cpfile, curr, curr_bh, kaddr);
675 list = &cp->cp_snapshot_list;
676 prev = le64_to_cpu(list->ssl_prev);
677 }
678 kunmap_atomic(kaddr);
679
680 if (prev != 0) {
681 ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
682 &prev_bh);
683 if (ret < 0)
684 goto out_curr;
685 } else {
686 prev_bh = header_bh;
687 get_bh(prev_bh);
688 }
689
690 kaddr = kmap_atomic(curr_bh->b_page);
691 list = nilfs_cpfile_block_get_snapshot_list(
692 cpfile, curr, curr_bh, kaddr);
693 list->ssl_prev = cpu_to_le64(cno);
694 kunmap_atomic(kaddr);
695
696 kaddr = kmap_atomic(cp_bh->b_page);
697 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
698 cp->cp_snapshot_list.ssl_next = cpu_to_le64(curr);
699 cp->cp_snapshot_list.ssl_prev = cpu_to_le64(prev);
700 nilfs_checkpoint_set_snapshot(cp);
701 kunmap_atomic(kaddr);
702
703 kaddr = kmap_atomic(prev_bh->b_page);
704 list = nilfs_cpfile_block_get_snapshot_list(
705 cpfile, prev, prev_bh, kaddr);
706 list->ssl_next = cpu_to_le64(cno);
707 kunmap_atomic(kaddr);
708
709 kaddr = kmap_atomic(header_bh->b_page);
710 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
711 le64_add_cpu(&header->ch_nsnapshots, 1);
712 kunmap_atomic(kaddr);
713
714 mark_buffer_dirty(prev_bh);
715 mark_buffer_dirty(curr_bh);
716 mark_buffer_dirty(cp_bh);
717 mark_buffer_dirty(header_bh);
718 nilfs_mdt_mark_dirty(cpfile);
719
720 brelse(prev_bh);
721
722 out_curr:
723 brelse(curr_bh);
724
725 out_header:
726 brelse(header_bh);
727
728 out_cp:
729 brelse(cp_bh);
730
731 out_sem:
732 up_write(&NILFS_MDT(cpfile)->mi_sem);
733 return ret;
734}
735
736static int nilfs_cpfile_clear_snapshot(struct inode *cpfile, __u64 cno)
737{
738 struct buffer_head *header_bh, *next_bh, *prev_bh, *cp_bh;
739 struct nilfs_cpfile_header *header;
740 struct nilfs_checkpoint *cp;
741 struct nilfs_snapshot_list *list;
742 __u64 next, prev;
743 void *kaddr;
744 int ret;
745
746 if (cno == 0)
747 return -ENOENT; /* checkpoint number 0 is invalid */
748 down_write(&NILFS_MDT(cpfile)->mi_sem);
749
750 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
751 if (ret < 0)
752 goto out_sem;
753 kaddr = kmap_atomic(cp_bh->b_page);
754 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
755 if (nilfs_checkpoint_invalid(cp)) {
756 ret = -ENOENT;
757 kunmap_atomic(kaddr);
758 goto out_cp;
759 }
760 if (!nilfs_checkpoint_snapshot(cp)) {
761 ret = 0;
762 kunmap_atomic(kaddr);
763 goto out_cp;
764 }
765
766 list = &cp->cp_snapshot_list;
767 next = le64_to_cpu(list->ssl_next);
768 prev = le64_to_cpu(list->ssl_prev);
769 kunmap_atomic(kaddr);
770
771 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
772 if (ret < 0)
773 goto out_cp;
774 if (next != 0) {
775 ret = nilfs_cpfile_get_checkpoint_block(cpfile, next, 0,
776 &next_bh);
777 if (ret < 0)
778 goto out_header;
779 } else {
780 next_bh = header_bh;
781 get_bh(next_bh);
782 }
783 if (prev != 0) {
784 ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
785 &prev_bh);
786 if (ret < 0)
787 goto out_next;
788 } else {
789 prev_bh = header_bh;
790 get_bh(prev_bh);
791 }
792
793 kaddr = kmap_atomic(next_bh->b_page);
794 list = nilfs_cpfile_block_get_snapshot_list(
795 cpfile, next, next_bh, kaddr);
796 list->ssl_prev = cpu_to_le64(prev);
797 kunmap_atomic(kaddr);
798
799 kaddr = kmap_atomic(prev_bh->b_page);
800 list = nilfs_cpfile_block_get_snapshot_list(
801 cpfile, prev, prev_bh, kaddr);
802 list->ssl_next = cpu_to_le64(next);
803 kunmap_atomic(kaddr);
804
805 kaddr = kmap_atomic(cp_bh->b_page);
806 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
807 cp->cp_snapshot_list.ssl_next = cpu_to_le64(0);
808 cp->cp_snapshot_list.ssl_prev = cpu_to_le64(0);
809 nilfs_checkpoint_clear_snapshot(cp);
810 kunmap_atomic(kaddr);
811
812 kaddr = kmap_atomic(header_bh->b_page);
813 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
814 le64_add_cpu(&header->ch_nsnapshots, -1);
815 kunmap_atomic(kaddr);
816
817 mark_buffer_dirty(next_bh);
818 mark_buffer_dirty(prev_bh);
819 mark_buffer_dirty(cp_bh);
820 mark_buffer_dirty(header_bh);
821 nilfs_mdt_mark_dirty(cpfile);
822
823 brelse(prev_bh);
824
825 out_next:
826 brelse(next_bh);
827
828 out_header:
829 brelse(header_bh);
830
831 out_cp:
832 brelse(cp_bh);
833
834 out_sem:
835 up_write(&NILFS_MDT(cpfile)->mi_sem);
836 return ret;
837}
838
839/**
840 * nilfs_cpfile_is_snapshot -
841 * @cpfile: inode of checkpoint file
842 * @cno: checkpoint number
843 *
844 * Description:
845 *
846 * Return Value: On success, 1 is returned if the checkpoint specified by
847 * @cno is a snapshot, or 0 if not. On error, one of the following negative
848 * error codes is returned.
849 *
850 * %-EIO - I/O error.
851 *
852 * %-ENOMEM - Insufficient amount of memory available.
853 *
854 * %-ENOENT - No such checkpoint.
855 */
856int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
857{
858 struct buffer_head *bh;
859 struct nilfs_checkpoint *cp;
860 void *kaddr;
861 int ret;
862
863 /*
864 * CP number is invalid if it's zero or larger than the
865 * largest existing one.
866 */
867 if (cno == 0 || cno >= nilfs_mdt_cno(cpfile))
868 return -ENOENT;
869 down_read(&NILFS_MDT(cpfile)->mi_sem);
870
871 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
872 if (ret < 0)
873 goto out;
874 kaddr = kmap_atomic(bh->b_page);
875 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
876 if (nilfs_checkpoint_invalid(cp))
877 ret = -ENOENT;
878 else
879 ret = nilfs_checkpoint_snapshot(cp);
880 kunmap_atomic(kaddr);
881 brelse(bh);
882
883 out:
884 up_read(&NILFS_MDT(cpfile)->mi_sem);
885 return ret;
886}
887
888/**
889 * nilfs_cpfile_change_cpmode - change checkpoint mode
890 * @cpfile: inode of checkpoint file
891 * @cno: checkpoint number
892 * @mode: mode of checkpoint
893 *
894 * Description: nilfs_change_cpmode() changes the mode of the checkpoint
895 * specified by @cno. The mode @mode is NILFS_CHECKPOINT or NILFS_SNAPSHOT.
896 *
897 * Return Value: On success, 0 is returned. On error, one of the following
898 * negative error codes is returned.
899 *
900 * %-EIO - I/O error.
901 *
902 * %-ENOMEM - Insufficient amount of memory available.
903 *
904 * %-ENOENT - No such checkpoint.
905 */
906int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode)
907{
908 int ret;
909
910 switch (mode) {
911 case NILFS_CHECKPOINT:
912 if (nilfs_checkpoint_is_mounted(cpfile->i_sb, cno))
913 /*
914 * Current implementation does not have to protect
915 * plain read-only mounts since they are exclusive
916 * with a read/write mount and are protected from the
917 * cleaner.
918 */
919 ret = -EBUSY;
920 else
921 ret = nilfs_cpfile_clear_snapshot(cpfile, cno);
922 return ret;
923 case NILFS_SNAPSHOT:
924 return nilfs_cpfile_set_snapshot(cpfile, cno);
925 default:
926 return -EINVAL;
927 }
928}
929
930/**
931 * nilfs_cpfile_get_stat - get checkpoint statistics
932 * @cpfile: inode of checkpoint file
933 * @cpstat: pointer to a structure of checkpoint statistics
934 *
935 * Description: nilfs_cpfile_get_stat() returns information about checkpoints.
936 *
937 * Return Value: On success, 0 is returned, and checkpoints information is
938 * stored in the place pointed by @cpstat. On error, one of the following
939 * negative error codes is returned.
940 *
941 * %-EIO - I/O error.
942 *
943 * %-ENOMEM - Insufficient amount of memory available.
944 */
945int nilfs_cpfile_get_stat(struct inode *cpfile, struct nilfs_cpstat *cpstat)
946{
947 struct buffer_head *bh;
948 struct nilfs_cpfile_header *header;
949 void *kaddr;
950 int ret;
951
952 down_read(&NILFS_MDT(cpfile)->mi_sem);
953
954 ret = nilfs_cpfile_get_header_block(cpfile, &bh);
955 if (ret < 0)
956 goto out_sem;
957 kaddr = kmap_atomic(bh->b_page);
958 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
959 cpstat->cs_cno = nilfs_mdt_cno(cpfile);
960 cpstat->cs_ncps = le64_to_cpu(header->ch_ncheckpoints);
961 cpstat->cs_nsss = le64_to_cpu(header->ch_nsnapshots);
962 kunmap_atomic(kaddr);
963 brelse(bh);
964
965 out_sem:
966 up_read(&NILFS_MDT(cpfile)->mi_sem);
967 return ret;
968}
969
970/**
971 * nilfs_cpfile_read - read or get cpfile inode
972 * @sb: super block instance
973 * @cpsize: size of a checkpoint entry
974 * @raw_inode: on-disk cpfile inode
975 * @inodep: buffer to store the inode
976 */
977int nilfs_cpfile_read(struct super_block *sb, size_t cpsize,
978 struct nilfs_inode *raw_inode, struct inode **inodep)
979{
980 struct inode *cpfile;
981 int err;
982
983 if (cpsize > sb->s_blocksize) {
984 nilfs_err(sb, "too large checkpoint size: %zu bytes", cpsize);
985 return -EINVAL;
986 } else if (cpsize < NILFS_MIN_CHECKPOINT_SIZE) {
987 nilfs_err(sb, "too small checkpoint size: %zu bytes", cpsize);
988 return -EINVAL;
989 }
990
991 cpfile = nilfs_iget_locked(sb, NULL, NILFS_CPFILE_INO);
992 if (unlikely(!cpfile))
993 return -ENOMEM;
994 if (!(cpfile->i_state & I_NEW))
995 goto out;
996
997 err = nilfs_mdt_init(cpfile, NILFS_MDT_GFP, 0);
998 if (err)
999 goto failed;
1000
1001 nilfs_mdt_set_entry_size(cpfile, cpsize,
1002 sizeof(struct nilfs_cpfile_header));
1003
1004 err = nilfs_read_inode_common(cpfile, raw_inode);
1005 if (err)
1006 goto failed;
1007
1008 unlock_new_inode(cpfile);
1009 out:
1010 *inodep = cpfile;
1011 return 0;
1012 failed:
1013 iget_failed(cpfile);
1014 return err;
1015}
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
19static inline unsigned long
20nilfs_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 */
26static unsigned long
27nilfs_cpfile_get_blkoff(const struct inode *cpfile, __u64 cno)
28{
29 __u64 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
30
31 do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile));
32 return (unsigned long)tcno;
33}
34
35/* offset in block */
36static unsigned long
37nilfs_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
44static __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
51static unsigned long
52nilfs_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
62static 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
68static unsigned int
69nilfs_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
82static unsigned int
83nilfs_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
97static inline struct nilfs_cpfile_header *
98nilfs_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
105static struct nilfs_checkpoint *
106nilfs_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
114static 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
128static 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
134static 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 */
161static 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
182static 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_get_checkpoint - get a checkpoint
191 * @cpfile: inode of checkpoint file
192 * @cno: checkpoint number
193 * @create: create flag
194 * @cpp: pointer to a checkpoint
195 * @bhp: pointer to a buffer head
196 *
197 * Description: nilfs_cpfile_get_checkpoint() acquires the checkpoint
198 * specified by @cno. A new checkpoint will be created if @cno is the current
199 * checkpoint number and @create is nonzero.
200 *
201 * Return Value: On success, 0 is returned, and the checkpoint and the
202 * buffer head of the buffer on which the checkpoint is located are stored in
203 * the place pointed by @cpp and @bhp, respectively. On error, one of the
204 * following negative error codes is returned.
205 *
206 * %-EIO - I/O error.
207 *
208 * %-ENOMEM - Insufficient amount of memory available.
209 *
210 * %-ENOENT - No such checkpoint.
211 *
212 * %-EINVAL - invalid checkpoint.
213 */
214int nilfs_cpfile_get_checkpoint(struct inode *cpfile,
215 __u64 cno,
216 int create,
217 struct nilfs_checkpoint **cpp,
218 struct buffer_head **bhp)
219{
220 struct buffer_head *header_bh, *cp_bh;
221 struct nilfs_cpfile_header *header;
222 struct nilfs_checkpoint *cp;
223 void *kaddr;
224 int ret;
225
226 if (unlikely(cno < 1 || cno > nilfs_mdt_cno(cpfile) ||
227 (cno < nilfs_mdt_cno(cpfile) && create)))
228 return -EINVAL;
229
230 down_write(&NILFS_MDT(cpfile)->mi_sem);
231
232 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
233 if (ret < 0)
234 goto out_sem;
235 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, create, &cp_bh);
236 if (ret < 0)
237 goto out_header;
238 kaddr = kmap(cp_bh->b_page);
239 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
240 if (nilfs_checkpoint_invalid(cp)) {
241 if (!create) {
242 kunmap(cp_bh->b_page);
243 brelse(cp_bh);
244 ret = -ENOENT;
245 goto out_header;
246 }
247 /* a newly-created checkpoint */
248 nilfs_checkpoint_clear_invalid(cp);
249 if (!nilfs_cpfile_is_in_first(cpfile, cno))
250 nilfs_cpfile_block_add_valid_checkpoints(cpfile, cp_bh,
251 kaddr, 1);
252 mark_buffer_dirty(cp_bh);
253
254 kaddr = kmap_atomic(header_bh->b_page);
255 header = nilfs_cpfile_block_get_header(cpfile, header_bh,
256 kaddr);
257 le64_add_cpu(&header->ch_ncheckpoints, 1);
258 kunmap_atomic(kaddr);
259 mark_buffer_dirty(header_bh);
260 nilfs_mdt_mark_dirty(cpfile);
261 }
262
263 if (cpp != NULL)
264 *cpp = cp;
265 *bhp = cp_bh;
266
267 out_header:
268 brelse(header_bh);
269
270 out_sem:
271 up_write(&NILFS_MDT(cpfile)->mi_sem);
272 return ret;
273}
274
275/**
276 * nilfs_cpfile_put_checkpoint - put a checkpoint
277 * @cpfile: inode of checkpoint file
278 * @cno: checkpoint number
279 * @bh: buffer head
280 *
281 * Description: nilfs_cpfile_put_checkpoint() releases the checkpoint
282 * specified by @cno. @bh must be the buffer head which has been returned by
283 * a previous call to nilfs_cpfile_get_checkpoint() with @cno.
284 */
285void nilfs_cpfile_put_checkpoint(struct inode *cpfile, __u64 cno,
286 struct buffer_head *bh)
287{
288 kunmap(bh->b_page);
289 brelse(bh);
290}
291
292/**
293 * nilfs_cpfile_delete_checkpoints - delete checkpoints
294 * @cpfile: inode of checkpoint file
295 * @start: start checkpoint number
296 * @end: end checkpoint number
297 *
298 * Description: nilfs_cpfile_delete_checkpoints() deletes the checkpoints in
299 * the period from @start to @end, excluding @end itself. The checkpoints
300 * which have been already deleted are ignored.
301 *
302 * Return Value: On success, 0 is returned. On error, one of the following
303 * negative error codes is returned.
304 *
305 * %-EIO - I/O error.
306 *
307 * %-ENOMEM - Insufficient amount of memory available.
308 *
309 * %-EINVAL - invalid checkpoints.
310 */
311int nilfs_cpfile_delete_checkpoints(struct inode *cpfile,
312 __u64 start,
313 __u64 end)
314{
315 struct buffer_head *header_bh, *cp_bh;
316 struct nilfs_cpfile_header *header;
317 struct nilfs_checkpoint *cp;
318 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
319 __u64 cno;
320 void *kaddr;
321 unsigned long tnicps;
322 int ret, ncps, nicps, nss, count, i;
323
324 if (unlikely(start == 0 || start > end)) {
325 nilfs_err(cpfile->i_sb,
326 "cannot delete checkpoints: invalid range [%llu, %llu)",
327 (unsigned long long)start, (unsigned long long)end);
328 return -EINVAL;
329 }
330
331 down_write(&NILFS_MDT(cpfile)->mi_sem);
332
333 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
334 if (ret < 0)
335 goto out_sem;
336 tnicps = 0;
337 nss = 0;
338
339 for (cno = start; cno < end; cno += ncps) {
340 ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, end);
341 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
342 if (ret < 0) {
343 if (ret != -ENOENT)
344 break;
345 /* skip hole */
346 ret = 0;
347 continue;
348 }
349
350 kaddr = kmap_atomic(cp_bh->b_page);
351 cp = nilfs_cpfile_block_get_checkpoint(
352 cpfile, cno, cp_bh, kaddr);
353 nicps = 0;
354 for (i = 0; i < ncps; i++, cp = (void *)cp + cpsz) {
355 if (nilfs_checkpoint_snapshot(cp)) {
356 nss++;
357 } else if (!nilfs_checkpoint_invalid(cp)) {
358 nilfs_checkpoint_set_invalid(cp);
359 nicps++;
360 }
361 }
362 if (nicps > 0) {
363 tnicps += nicps;
364 mark_buffer_dirty(cp_bh);
365 nilfs_mdt_mark_dirty(cpfile);
366 if (!nilfs_cpfile_is_in_first(cpfile, cno)) {
367 count =
368 nilfs_cpfile_block_sub_valid_checkpoints(
369 cpfile, cp_bh, kaddr, nicps);
370 if (count == 0) {
371 /* make hole */
372 kunmap_atomic(kaddr);
373 brelse(cp_bh);
374 ret =
375 nilfs_cpfile_delete_checkpoint_block(
376 cpfile, cno);
377 if (ret == 0)
378 continue;
379 nilfs_err(cpfile->i_sb,
380 "error %d deleting checkpoint block",
381 ret);
382 break;
383 }
384 }
385 }
386
387 kunmap_atomic(kaddr);
388 brelse(cp_bh);
389 }
390
391 if (tnicps > 0) {
392 kaddr = kmap_atomic(header_bh->b_page);
393 header = nilfs_cpfile_block_get_header(cpfile, header_bh,
394 kaddr);
395 le64_add_cpu(&header->ch_ncheckpoints, -(u64)tnicps);
396 mark_buffer_dirty(header_bh);
397 nilfs_mdt_mark_dirty(cpfile);
398 kunmap_atomic(kaddr);
399 }
400
401 brelse(header_bh);
402 if (nss > 0)
403 ret = -EBUSY;
404
405 out_sem:
406 up_write(&NILFS_MDT(cpfile)->mi_sem);
407 return ret;
408}
409
410static void nilfs_cpfile_checkpoint_to_cpinfo(struct inode *cpfile,
411 struct nilfs_checkpoint *cp,
412 struct nilfs_cpinfo *ci)
413{
414 ci->ci_flags = le32_to_cpu(cp->cp_flags);
415 ci->ci_cno = le64_to_cpu(cp->cp_cno);
416 ci->ci_create = le64_to_cpu(cp->cp_create);
417 ci->ci_nblk_inc = le64_to_cpu(cp->cp_nblk_inc);
418 ci->ci_inodes_count = le64_to_cpu(cp->cp_inodes_count);
419 ci->ci_blocks_count = le64_to_cpu(cp->cp_blocks_count);
420 ci->ci_next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
421}
422
423static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop,
424 void *buf, unsigned int cisz,
425 size_t nci)
426{
427 struct nilfs_checkpoint *cp;
428 struct nilfs_cpinfo *ci = buf;
429 struct buffer_head *bh;
430 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
431 __u64 cur_cno = nilfs_mdt_cno(cpfile), cno = *cnop;
432 void *kaddr;
433 int n, ret;
434 int ncps, i;
435
436 if (cno == 0)
437 return -ENOENT; /* checkpoint number 0 is invalid */
438 down_read(&NILFS_MDT(cpfile)->mi_sem);
439
440 for (n = 0; n < nci; cno += ncps) {
441 ret = nilfs_cpfile_find_checkpoint_block(
442 cpfile, cno, cur_cno - 1, &cno, &bh);
443 if (ret < 0) {
444 if (likely(ret == -ENOENT))
445 break;
446 goto out;
447 }
448 ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, cur_cno);
449
450 kaddr = kmap_atomic(bh->b_page);
451 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
452 for (i = 0; i < ncps && n < nci; i++, cp = (void *)cp + cpsz) {
453 if (!nilfs_checkpoint_invalid(cp)) {
454 nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp,
455 ci);
456 ci = (void *)ci + cisz;
457 n++;
458 }
459 }
460 kunmap_atomic(kaddr);
461 brelse(bh);
462 }
463
464 ret = n;
465 if (n > 0) {
466 ci = (void *)ci - cisz;
467 *cnop = ci->ci_cno + 1;
468 }
469
470 out:
471 up_read(&NILFS_MDT(cpfile)->mi_sem);
472 return ret;
473}
474
475static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
476 void *buf, unsigned int cisz,
477 size_t nci)
478{
479 struct buffer_head *bh;
480 struct nilfs_cpfile_header *header;
481 struct nilfs_checkpoint *cp;
482 struct nilfs_cpinfo *ci = buf;
483 __u64 curr = *cnop, next;
484 unsigned long curr_blkoff, next_blkoff;
485 void *kaddr;
486 int n = 0, ret;
487
488 down_read(&NILFS_MDT(cpfile)->mi_sem);
489
490 if (curr == 0) {
491 ret = nilfs_cpfile_get_header_block(cpfile, &bh);
492 if (ret < 0)
493 goto out;
494 kaddr = kmap_atomic(bh->b_page);
495 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
496 curr = le64_to_cpu(header->ch_snapshot_list.ssl_next);
497 kunmap_atomic(kaddr);
498 brelse(bh);
499 if (curr == 0) {
500 ret = 0;
501 goto out;
502 }
503 } else if (unlikely(curr == ~(__u64)0)) {
504 ret = 0;
505 goto out;
506 }
507
508 curr_blkoff = nilfs_cpfile_get_blkoff(cpfile, curr);
509 ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr, 0, &bh);
510 if (unlikely(ret < 0)) {
511 if (ret == -ENOENT)
512 ret = 0; /* No snapshots (started from a hole block) */
513 goto out;
514 }
515 kaddr = kmap_atomic(bh->b_page);
516 while (n < nci) {
517 cp = nilfs_cpfile_block_get_checkpoint(cpfile, curr, bh, kaddr);
518 curr = ~(__u64)0; /* Terminator */
519 if (unlikely(nilfs_checkpoint_invalid(cp) ||
520 !nilfs_checkpoint_snapshot(cp)))
521 break;
522 nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, ci);
523 ci = (void *)ci + cisz;
524 n++;
525 next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
526 if (next == 0)
527 break; /* reach end of the snapshot list */
528
529 next_blkoff = nilfs_cpfile_get_blkoff(cpfile, next);
530 if (curr_blkoff != next_blkoff) {
531 kunmap_atomic(kaddr);
532 brelse(bh);
533 ret = nilfs_cpfile_get_checkpoint_block(cpfile, next,
534 0, &bh);
535 if (unlikely(ret < 0)) {
536 WARN_ON(ret == -ENOENT);
537 goto out;
538 }
539 kaddr = kmap_atomic(bh->b_page);
540 }
541 curr = next;
542 curr_blkoff = next_blkoff;
543 }
544 kunmap_atomic(kaddr);
545 brelse(bh);
546 *cnop = curr;
547 ret = n;
548
549 out:
550 up_read(&NILFS_MDT(cpfile)->mi_sem);
551 return ret;
552}
553
554/**
555 * nilfs_cpfile_get_cpinfo - get information on checkpoints
556 * @cpfile: checkpoint file inode
557 * @cnop: place to pass a starting checkpoint number and receive a
558 * checkpoint number to continue the search
559 * @mode: mode of checkpoints that the caller wants to retrieve
560 * @buf: buffer for storing checkpoints' information
561 * @cisz: byte size of one checkpoint info item in array
562 * @nci: number of checkpoint info items to retrieve
563 *
564 * nilfs_cpfile_get_cpinfo() searches for checkpoints in @mode state
565 * starting from the checkpoint number stored in @cnop, and stores
566 * information about found checkpoints in @buf.
567 * The buffer pointed to by @buf must be large enough to store information
568 * for @nci checkpoints. If at least one checkpoint information is
569 * successfully retrieved, @cnop is updated to point to the checkpoint
570 * number to continue searching.
571 *
572 * Return: Count of checkpoint info items stored in the output buffer on
573 * success, or the following negative error code on failure.
574 * * %-EINVAL - Invalid checkpoint mode.
575 * * %-ENOMEM - Insufficient memory available.
576 * * %-EIO - I/O error (including metadata corruption).
577 * * %-ENOENT - Invalid checkpoint number specified.
578 */
579
580ssize_t nilfs_cpfile_get_cpinfo(struct inode *cpfile, __u64 *cnop, int mode,
581 void *buf, unsigned int cisz, size_t nci)
582{
583 switch (mode) {
584 case NILFS_CHECKPOINT:
585 return nilfs_cpfile_do_get_cpinfo(cpfile, cnop, buf, cisz, nci);
586 case NILFS_SNAPSHOT:
587 return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, buf, cisz, nci);
588 default:
589 return -EINVAL;
590 }
591}
592
593/**
594 * nilfs_cpfile_delete_checkpoint -
595 * @cpfile:
596 * @cno:
597 */
598int nilfs_cpfile_delete_checkpoint(struct inode *cpfile, __u64 cno)
599{
600 struct nilfs_cpinfo ci;
601 __u64 tcno = cno;
602 ssize_t nci;
603
604 nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, sizeof(ci), 1);
605 if (nci < 0)
606 return nci;
607 else if (nci == 0 || ci.ci_cno != cno)
608 return -ENOENT;
609 else if (nilfs_cpinfo_snapshot(&ci))
610 return -EBUSY;
611
612 return nilfs_cpfile_delete_checkpoints(cpfile, cno, cno + 1);
613}
614
615static struct nilfs_snapshot_list *
616nilfs_cpfile_block_get_snapshot_list(const struct inode *cpfile,
617 __u64 cno,
618 struct buffer_head *bh,
619 void *kaddr)
620{
621 struct nilfs_cpfile_header *header;
622 struct nilfs_checkpoint *cp;
623 struct nilfs_snapshot_list *list;
624
625 if (cno != 0) {
626 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
627 list = &cp->cp_snapshot_list;
628 } else {
629 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
630 list = &header->ch_snapshot_list;
631 }
632 return list;
633}
634
635static int nilfs_cpfile_set_snapshot(struct inode *cpfile, __u64 cno)
636{
637 struct buffer_head *header_bh, *curr_bh, *prev_bh, *cp_bh;
638 struct nilfs_cpfile_header *header;
639 struct nilfs_checkpoint *cp;
640 struct nilfs_snapshot_list *list;
641 __u64 curr, prev;
642 unsigned long curr_blkoff, prev_blkoff;
643 void *kaddr;
644 int ret;
645
646 if (cno == 0)
647 return -ENOENT; /* checkpoint number 0 is invalid */
648 down_write(&NILFS_MDT(cpfile)->mi_sem);
649
650 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
651 if (ret < 0)
652 goto out_sem;
653 kaddr = kmap_atomic(cp_bh->b_page);
654 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
655 if (nilfs_checkpoint_invalid(cp)) {
656 ret = -ENOENT;
657 kunmap_atomic(kaddr);
658 goto out_cp;
659 }
660 if (nilfs_checkpoint_snapshot(cp)) {
661 ret = 0;
662 kunmap_atomic(kaddr);
663 goto out_cp;
664 }
665 kunmap_atomic(kaddr);
666
667 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
668 if (ret < 0)
669 goto out_cp;
670 kaddr = kmap_atomic(header_bh->b_page);
671 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
672 list = &header->ch_snapshot_list;
673 curr_bh = header_bh;
674 get_bh(curr_bh);
675 curr = 0;
676 curr_blkoff = 0;
677 prev = le64_to_cpu(list->ssl_prev);
678 while (prev > cno) {
679 prev_blkoff = nilfs_cpfile_get_blkoff(cpfile, prev);
680 curr = prev;
681 if (curr_blkoff != prev_blkoff) {
682 kunmap_atomic(kaddr);
683 brelse(curr_bh);
684 ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr,
685 0, &curr_bh);
686 if (ret < 0)
687 goto out_header;
688 kaddr = kmap_atomic(curr_bh->b_page);
689 }
690 curr_blkoff = prev_blkoff;
691 cp = nilfs_cpfile_block_get_checkpoint(
692 cpfile, curr, curr_bh, kaddr);
693 list = &cp->cp_snapshot_list;
694 prev = le64_to_cpu(list->ssl_prev);
695 }
696 kunmap_atomic(kaddr);
697
698 if (prev != 0) {
699 ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
700 &prev_bh);
701 if (ret < 0)
702 goto out_curr;
703 } else {
704 prev_bh = header_bh;
705 get_bh(prev_bh);
706 }
707
708 kaddr = kmap_atomic(curr_bh->b_page);
709 list = nilfs_cpfile_block_get_snapshot_list(
710 cpfile, curr, curr_bh, kaddr);
711 list->ssl_prev = cpu_to_le64(cno);
712 kunmap_atomic(kaddr);
713
714 kaddr = kmap_atomic(cp_bh->b_page);
715 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
716 cp->cp_snapshot_list.ssl_next = cpu_to_le64(curr);
717 cp->cp_snapshot_list.ssl_prev = cpu_to_le64(prev);
718 nilfs_checkpoint_set_snapshot(cp);
719 kunmap_atomic(kaddr);
720
721 kaddr = kmap_atomic(prev_bh->b_page);
722 list = nilfs_cpfile_block_get_snapshot_list(
723 cpfile, prev, prev_bh, kaddr);
724 list->ssl_next = cpu_to_le64(cno);
725 kunmap_atomic(kaddr);
726
727 kaddr = kmap_atomic(header_bh->b_page);
728 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
729 le64_add_cpu(&header->ch_nsnapshots, 1);
730 kunmap_atomic(kaddr);
731
732 mark_buffer_dirty(prev_bh);
733 mark_buffer_dirty(curr_bh);
734 mark_buffer_dirty(cp_bh);
735 mark_buffer_dirty(header_bh);
736 nilfs_mdt_mark_dirty(cpfile);
737
738 brelse(prev_bh);
739
740 out_curr:
741 brelse(curr_bh);
742
743 out_header:
744 brelse(header_bh);
745
746 out_cp:
747 brelse(cp_bh);
748
749 out_sem:
750 up_write(&NILFS_MDT(cpfile)->mi_sem);
751 return ret;
752}
753
754static int nilfs_cpfile_clear_snapshot(struct inode *cpfile, __u64 cno)
755{
756 struct buffer_head *header_bh, *next_bh, *prev_bh, *cp_bh;
757 struct nilfs_cpfile_header *header;
758 struct nilfs_checkpoint *cp;
759 struct nilfs_snapshot_list *list;
760 __u64 next, prev;
761 void *kaddr;
762 int ret;
763
764 if (cno == 0)
765 return -ENOENT; /* checkpoint number 0 is invalid */
766 down_write(&NILFS_MDT(cpfile)->mi_sem);
767
768 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
769 if (ret < 0)
770 goto out_sem;
771 kaddr = kmap_atomic(cp_bh->b_page);
772 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
773 if (nilfs_checkpoint_invalid(cp)) {
774 ret = -ENOENT;
775 kunmap_atomic(kaddr);
776 goto out_cp;
777 }
778 if (!nilfs_checkpoint_snapshot(cp)) {
779 ret = 0;
780 kunmap_atomic(kaddr);
781 goto out_cp;
782 }
783
784 list = &cp->cp_snapshot_list;
785 next = le64_to_cpu(list->ssl_next);
786 prev = le64_to_cpu(list->ssl_prev);
787 kunmap_atomic(kaddr);
788
789 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
790 if (ret < 0)
791 goto out_cp;
792 if (next != 0) {
793 ret = nilfs_cpfile_get_checkpoint_block(cpfile, next, 0,
794 &next_bh);
795 if (ret < 0)
796 goto out_header;
797 } else {
798 next_bh = header_bh;
799 get_bh(next_bh);
800 }
801 if (prev != 0) {
802 ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
803 &prev_bh);
804 if (ret < 0)
805 goto out_next;
806 } else {
807 prev_bh = header_bh;
808 get_bh(prev_bh);
809 }
810
811 kaddr = kmap_atomic(next_bh->b_page);
812 list = nilfs_cpfile_block_get_snapshot_list(
813 cpfile, next, next_bh, kaddr);
814 list->ssl_prev = cpu_to_le64(prev);
815 kunmap_atomic(kaddr);
816
817 kaddr = kmap_atomic(prev_bh->b_page);
818 list = nilfs_cpfile_block_get_snapshot_list(
819 cpfile, prev, prev_bh, kaddr);
820 list->ssl_next = cpu_to_le64(next);
821 kunmap_atomic(kaddr);
822
823 kaddr = kmap_atomic(cp_bh->b_page);
824 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
825 cp->cp_snapshot_list.ssl_next = cpu_to_le64(0);
826 cp->cp_snapshot_list.ssl_prev = cpu_to_le64(0);
827 nilfs_checkpoint_clear_snapshot(cp);
828 kunmap_atomic(kaddr);
829
830 kaddr = kmap_atomic(header_bh->b_page);
831 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
832 le64_add_cpu(&header->ch_nsnapshots, -1);
833 kunmap_atomic(kaddr);
834
835 mark_buffer_dirty(next_bh);
836 mark_buffer_dirty(prev_bh);
837 mark_buffer_dirty(cp_bh);
838 mark_buffer_dirty(header_bh);
839 nilfs_mdt_mark_dirty(cpfile);
840
841 brelse(prev_bh);
842
843 out_next:
844 brelse(next_bh);
845
846 out_header:
847 brelse(header_bh);
848
849 out_cp:
850 brelse(cp_bh);
851
852 out_sem:
853 up_write(&NILFS_MDT(cpfile)->mi_sem);
854 return ret;
855}
856
857/**
858 * nilfs_cpfile_is_snapshot -
859 * @cpfile: inode of checkpoint file
860 * @cno: checkpoint number
861 *
862 * Description:
863 *
864 * Return Value: On success, 1 is returned if the checkpoint specified by
865 * @cno is a snapshot, or 0 if not. On error, one of the following negative
866 * error codes is returned.
867 *
868 * %-EIO - I/O error.
869 *
870 * %-ENOMEM - Insufficient amount of memory available.
871 *
872 * %-ENOENT - No such checkpoint.
873 */
874int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
875{
876 struct buffer_head *bh;
877 struct nilfs_checkpoint *cp;
878 void *kaddr;
879 int ret;
880
881 /*
882 * CP number is invalid if it's zero or larger than the
883 * largest existing one.
884 */
885 if (cno == 0 || cno >= nilfs_mdt_cno(cpfile))
886 return -ENOENT;
887 down_read(&NILFS_MDT(cpfile)->mi_sem);
888
889 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
890 if (ret < 0)
891 goto out;
892 kaddr = kmap_atomic(bh->b_page);
893 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
894 if (nilfs_checkpoint_invalid(cp))
895 ret = -ENOENT;
896 else
897 ret = nilfs_checkpoint_snapshot(cp);
898 kunmap_atomic(kaddr);
899 brelse(bh);
900
901 out:
902 up_read(&NILFS_MDT(cpfile)->mi_sem);
903 return ret;
904}
905
906/**
907 * nilfs_cpfile_change_cpmode - change checkpoint mode
908 * @cpfile: inode of checkpoint file
909 * @cno: checkpoint number
910 * @mode: mode of checkpoint
911 *
912 * Description: nilfs_change_cpmode() changes the mode of the checkpoint
913 * specified by @cno. The mode @mode is NILFS_CHECKPOINT or NILFS_SNAPSHOT.
914 *
915 * Return Value: On success, 0 is returned. On error, one of the following
916 * negative error codes is returned.
917 *
918 * %-EIO - I/O error.
919 *
920 * %-ENOMEM - Insufficient amount of memory available.
921 *
922 * %-ENOENT - No such checkpoint.
923 */
924int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode)
925{
926 int ret;
927
928 switch (mode) {
929 case NILFS_CHECKPOINT:
930 if (nilfs_checkpoint_is_mounted(cpfile->i_sb, cno))
931 /*
932 * Current implementation does not have to protect
933 * plain read-only mounts since they are exclusive
934 * with a read/write mount and are protected from the
935 * cleaner.
936 */
937 ret = -EBUSY;
938 else
939 ret = nilfs_cpfile_clear_snapshot(cpfile, cno);
940 return ret;
941 case NILFS_SNAPSHOT:
942 return nilfs_cpfile_set_snapshot(cpfile, cno);
943 default:
944 return -EINVAL;
945 }
946}
947
948/**
949 * nilfs_cpfile_get_stat - get checkpoint statistics
950 * @cpfile: inode of checkpoint file
951 * @cpstat: pointer to a structure of checkpoint statistics
952 *
953 * Description: nilfs_cpfile_get_stat() returns information about checkpoints.
954 *
955 * Return Value: On success, 0 is returned, and checkpoints information is
956 * stored in the place pointed by @cpstat. On error, one of the following
957 * negative error codes is returned.
958 *
959 * %-EIO - I/O error.
960 *
961 * %-ENOMEM - Insufficient amount of memory available.
962 */
963int nilfs_cpfile_get_stat(struct inode *cpfile, struct nilfs_cpstat *cpstat)
964{
965 struct buffer_head *bh;
966 struct nilfs_cpfile_header *header;
967 void *kaddr;
968 int ret;
969
970 down_read(&NILFS_MDT(cpfile)->mi_sem);
971
972 ret = nilfs_cpfile_get_header_block(cpfile, &bh);
973 if (ret < 0)
974 goto out_sem;
975 kaddr = kmap_atomic(bh->b_page);
976 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
977 cpstat->cs_cno = nilfs_mdt_cno(cpfile);
978 cpstat->cs_ncps = le64_to_cpu(header->ch_ncheckpoints);
979 cpstat->cs_nsss = le64_to_cpu(header->ch_nsnapshots);
980 kunmap_atomic(kaddr);
981 brelse(bh);
982
983 out_sem:
984 up_read(&NILFS_MDT(cpfile)->mi_sem);
985 return ret;
986}
987
988/**
989 * nilfs_cpfile_read - read or get cpfile inode
990 * @sb: super block instance
991 * @cpsize: size of a checkpoint entry
992 * @raw_inode: on-disk cpfile inode
993 * @inodep: buffer to store the inode
994 */
995int nilfs_cpfile_read(struct super_block *sb, size_t cpsize,
996 struct nilfs_inode *raw_inode, struct inode **inodep)
997{
998 struct inode *cpfile;
999 int err;
1000
1001 if (cpsize > sb->s_blocksize) {
1002 nilfs_err(sb, "too large checkpoint size: %zu bytes", cpsize);
1003 return -EINVAL;
1004 } else if (cpsize < NILFS_MIN_CHECKPOINT_SIZE) {
1005 nilfs_err(sb, "too small checkpoint size: %zu bytes", cpsize);
1006 return -EINVAL;
1007 }
1008
1009 cpfile = nilfs_iget_locked(sb, NULL, NILFS_CPFILE_INO);
1010 if (unlikely(!cpfile))
1011 return -ENOMEM;
1012 if (!(cpfile->i_state & I_NEW))
1013 goto out;
1014
1015 err = nilfs_mdt_init(cpfile, NILFS_MDT_GFP, 0);
1016 if (err)
1017 goto failed;
1018
1019 nilfs_mdt_set_entry_size(cpfile, cpsize,
1020 sizeof(struct nilfs_cpfile_header));
1021
1022 err = nilfs_read_inode_common(cpfile, raw_inode);
1023 if (err)
1024 goto failed;
1025
1026 unlock_new_inode(cpfile);
1027 out:
1028 *inodep = cpfile;
1029 return 0;
1030 failed:
1031 iget_failed(cpfile);
1032 return err;
1033}