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1/*
2 * cpfile.c - NILFS checkpoint file.
3 *
4 * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 *
20 * Written by Koji Sato <koji@osrg.net>.
21 */
22
23#include <linux/kernel.h>
24#include <linux/fs.h>
25#include <linux/string.h>
26#include <linux/buffer_head.h>
27#include <linux/errno.h>
28#include <linux/nilfs2_fs.h>
29#include "mdt.h"
30#include "cpfile.h"
31
32
33static inline unsigned long
34nilfs_cpfile_checkpoints_per_block(const struct inode *cpfile)
35{
36 return NILFS_MDT(cpfile)->mi_entries_per_block;
37}
38
39/* block number from the beginning of the file */
40static unsigned long
41nilfs_cpfile_get_blkoff(const struct inode *cpfile, __u64 cno)
42{
43 __u64 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
44 do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile));
45 return (unsigned long)tcno;
46}
47
48/* offset in block */
49static unsigned long
50nilfs_cpfile_get_offset(const struct inode *cpfile, __u64 cno)
51{
52 __u64 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
53 return do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile));
54}
55
56static __u64 nilfs_cpfile_first_checkpoint_in_block(const struct inode *cpfile,
57 unsigned long blkoff)
58{
59 return (__u64)nilfs_cpfile_checkpoints_per_block(cpfile) * blkoff
60 + 1 - NILFS_MDT(cpfile)->mi_first_entry_offset;
61}
62
63static unsigned long
64nilfs_cpfile_checkpoints_in_block(const struct inode *cpfile,
65 __u64 curr,
66 __u64 max)
67{
68 return min_t(__u64,
69 nilfs_cpfile_checkpoints_per_block(cpfile) -
70 nilfs_cpfile_get_offset(cpfile, curr),
71 max - curr);
72}
73
74static inline int nilfs_cpfile_is_in_first(const struct inode *cpfile,
75 __u64 cno)
76{
77 return nilfs_cpfile_get_blkoff(cpfile, cno) == 0;
78}
79
80static unsigned int
81nilfs_cpfile_block_add_valid_checkpoints(const struct inode *cpfile,
82 struct buffer_head *bh,
83 void *kaddr,
84 unsigned int n)
85{
86 struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
87 unsigned int count;
88
89 count = le32_to_cpu(cp->cp_checkpoints_count) + n;
90 cp->cp_checkpoints_count = cpu_to_le32(count);
91 return count;
92}
93
94static unsigned int
95nilfs_cpfile_block_sub_valid_checkpoints(const struct inode *cpfile,
96 struct buffer_head *bh,
97 void *kaddr,
98 unsigned int n)
99{
100 struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
101 unsigned int count;
102
103 WARN_ON(le32_to_cpu(cp->cp_checkpoints_count) < n);
104 count = le32_to_cpu(cp->cp_checkpoints_count) - n;
105 cp->cp_checkpoints_count = cpu_to_le32(count);
106 return count;
107}
108
109static inline struct nilfs_cpfile_header *
110nilfs_cpfile_block_get_header(const struct inode *cpfile,
111 struct buffer_head *bh,
112 void *kaddr)
113{
114 return kaddr + bh_offset(bh);
115}
116
117static struct nilfs_checkpoint *
118nilfs_cpfile_block_get_checkpoint(const struct inode *cpfile, __u64 cno,
119 struct buffer_head *bh,
120 void *kaddr)
121{
122 return kaddr + bh_offset(bh) + nilfs_cpfile_get_offset(cpfile, cno) *
123 NILFS_MDT(cpfile)->mi_entry_size;
124}
125
126static void nilfs_cpfile_block_init(struct inode *cpfile,
127 struct buffer_head *bh,
128 void *kaddr)
129{
130 struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
131 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
132 int n = nilfs_cpfile_checkpoints_per_block(cpfile);
133
134 while (n-- > 0) {
135 nilfs_checkpoint_set_invalid(cp);
136 cp = (void *)cp + cpsz;
137 }
138}
139
140static inline int nilfs_cpfile_get_header_block(struct inode *cpfile,
141 struct buffer_head **bhp)
142{
143 return nilfs_mdt_get_block(cpfile, 0, 0, NULL, bhp);
144}
145
146static inline int nilfs_cpfile_get_checkpoint_block(struct inode *cpfile,
147 __u64 cno,
148 int create,
149 struct buffer_head **bhp)
150{
151 return nilfs_mdt_get_block(cpfile,
152 nilfs_cpfile_get_blkoff(cpfile, cno),
153 create, nilfs_cpfile_block_init, bhp);
154}
155
156/**
157 * nilfs_cpfile_find_checkpoint_block - find and get a buffer on cpfile
158 * @cpfile: inode of cpfile
159 * @start_cno: start checkpoint number (inclusive)
160 * @end_cno: end checkpoint number (inclusive)
161 * @cnop: place to store the next checkpoint number
162 * @bhp: place to store a pointer to buffer_head struct
163 *
164 * Return Value: On success, it returns 0. On error, the following negative
165 * error code is returned.
166 *
167 * %-ENOMEM - Insufficient memory available.
168 *
169 * %-EIO - I/O error
170 *
171 * %-ENOENT - no block exists in the range.
172 */
173static int nilfs_cpfile_find_checkpoint_block(struct inode *cpfile,
174 __u64 start_cno, __u64 end_cno,
175 __u64 *cnop,
176 struct buffer_head **bhp)
177{
178 unsigned long start, end, blkoff;
179 int ret;
180
181 if (unlikely(start_cno > end_cno))
182 return -ENOENT;
183
184 start = nilfs_cpfile_get_blkoff(cpfile, start_cno);
185 end = nilfs_cpfile_get_blkoff(cpfile, end_cno);
186
187 ret = nilfs_mdt_find_block(cpfile, start, end, &blkoff, bhp);
188 if (!ret)
189 *cnop = (blkoff == start) ? start_cno :
190 nilfs_cpfile_first_checkpoint_in_block(cpfile, blkoff);
191 return ret;
192}
193
194static inline int nilfs_cpfile_delete_checkpoint_block(struct inode *cpfile,
195 __u64 cno)
196{
197 return nilfs_mdt_delete_block(cpfile,
198 nilfs_cpfile_get_blkoff(cpfile, cno));
199}
200
201/**
202 * nilfs_cpfile_get_checkpoint - get a checkpoint
203 * @cpfile: inode of checkpoint file
204 * @cno: checkpoint number
205 * @create: create flag
206 * @cpp: pointer to a checkpoint
207 * @bhp: pointer to a buffer head
208 *
209 * Description: nilfs_cpfile_get_checkpoint() acquires the checkpoint
210 * specified by @cno. A new checkpoint will be created if @cno is the current
211 * checkpoint number and @create is nonzero.
212 *
213 * Return Value: On success, 0 is returned, and the checkpoint and the
214 * buffer head of the buffer on which the checkpoint is located are stored in
215 * the place pointed by @cpp and @bhp, respectively. On error, one of the
216 * following negative error codes is returned.
217 *
218 * %-EIO - I/O error.
219 *
220 * %-ENOMEM - Insufficient amount of memory available.
221 *
222 * %-ENOENT - No such checkpoint.
223 *
224 * %-EINVAL - invalid checkpoint.
225 */
226int nilfs_cpfile_get_checkpoint(struct inode *cpfile,
227 __u64 cno,
228 int create,
229 struct nilfs_checkpoint **cpp,
230 struct buffer_head **bhp)
231{
232 struct buffer_head *header_bh, *cp_bh;
233 struct nilfs_cpfile_header *header;
234 struct nilfs_checkpoint *cp;
235 void *kaddr;
236 int ret;
237
238 if (unlikely(cno < 1 || cno > nilfs_mdt_cno(cpfile) ||
239 (cno < nilfs_mdt_cno(cpfile) && create)))
240 return -EINVAL;
241
242 down_write(&NILFS_MDT(cpfile)->mi_sem);
243
244 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
245 if (ret < 0)
246 goto out_sem;
247 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, create, &cp_bh);
248 if (ret < 0)
249 goto out_header;
250 kaddr = kmap(cp_bh->b_page);
251 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
252 if (nilfs_checkpoint_invalid(cp)) {
253 if (!create) {
254 kunmap(cp_bh->b_page);
255 brelse(cp_bh);
256 ret = -ENOENT;
257 goto out_header;
258 }
259 /* a newly-created checkpoint */
260 nilfs_checkpoint_clear_invalid(cp);
261 if (!nilfs_cpfile_is_in_first(cpfile, cno))
262 nilfs_cpfile_block_add_valid_checkpoints(cpfile, cp_bh,
263 kaddr, 1);
264 mark_buffer_dirty(cp_bh);
265
266 kaddr = kmap_atomic(header_bh->b_page);
267 header = nilfs_cpfile_block_get_header(cpfile, header_bh,
268 kaddr);
269 le64_add_cpu(&header->ch_ncheckpoints, 1);
270 kunmap_atomic(kaddr);
271 mark_buffer_dirty(header_bh);
272 nilfs_mdt_mark_dirty(cpfile);
273 }
274
275 if (cpp != NULL)
276 *cpp = cp;
277 *bhp = cp_bh;
278
279 out_header:
280 brelse(header_bh);
281
282 out_sem:
283 up_write(&NILFS_MDT(cpfile)->mi_sem);
284 return ret;
285}
286
287/**
288 * nilfs_cpfile_put_checkpoint - put a checkpoint
289 * @cpfile: inode of checkpoint file
290 * @cno: checkpoint number
291 * @bh: buffer head
292 *
293 * Description: nilfs_cpfile_put_checkpoint() releases the checkpoint
294 * specified by @cno. @bh must be the buffer head which has been returned by
295 * a previous call to nilfs_cpfile_get_checkpoint() with @cno.
296 */
297void nilfs_cpfile_put_checkpoint(struct inode *cpfile, __u64 cno,
298 struct buffer_head *bh)
299{
300 kunmap(bh->b_page);
301 brelse(bh);
302}
303
304/**
305 * nilfs_cpfile_delete_checkpoints - delete checkpoints
306 * @cpfile: inode of checkpoint file
307 * @start: start checkpoint number
308 * @end: end checkpoint numer
309 *
310 * Description: nilfs_cpfile_delete_checkpoints() deletes the checkpoints in
311 * the period from @start to @end, excluding @end itself. The checkpoints
312 * which have been already deleted are ignored.
313 *
314 * Return Value: On success, 0 is returned. On error, one of the following
315 * negative error codes is returned.
316 *
317 * %-EIO - I/O error.
318 *
319 * %-ENOMEM - Insufficient amount of memory available.
320 *
321 * %-EINVAL - invalid checkpoints.
322 */
323int nilfs_cpfile_delete_checkpoints(struct inode *cpfile,
324 __u64 start,
325 __u64 end)
326{
327 struct buffer_head *header_bh, *cp_bh;
328 struct nilfs_cpfile_header *header;
329 struct nilfs_checkpoint *cp;
330 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
331 __u64 cno;
332 void *kaddr;
333 unsigned long tnicps;
334 int ret, ncps, nicps, nss, count, i;
335
336 if (unlikely(start == 0 || start > end)) {
337 printk(KERN_ERR "%s: invalid range of checkpoint numbers: "
338 "[%llu, %llu)\n", __func__,
339 (unsigned long long)start, (unsigned long long)end);
340 return -EINVAL;
341 }
342
343 down_write(&NILFS_MDT(cpfile)->mi_sem);
344
345 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
346 if (ret < 0)
347 goto out_sem;
348 tnicps = 0;
349 nss = 0;
350
351 for (cno = start; cno < end; cno += ncps) {
352 ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, end);
353 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
354 if (ret < 0) {
355 if (ret != -ENOENT)
356 break;
357 /* skip hole */
358 ret = 0;
359 continue;
360 }
361
362 kaddr = kmap_atomic(cp_bh->b_page);
363 cp = nilfs_cpfile_block_get_checkpoint(
364 cpfile, cno, cp_bh, kaddr);
365 nicps = 0;
366 for (i = 0; i < ncps; i++, cp = (void *)cp + cpsz) {
367 if (nilfs_checkpoint_snapshot(cp)) {
368 nss++;
369 } else if (!nilfs_checkpoint_invalid(cp)) {
370 nilfs_checkpoint_set_invalid(cp);
371 nicps++;
372 }
373 }
374 if (nicps > 0) {
375 tnicps += nicps;
376 mark_buffer_dirty(cp_bh);
377 nilfs_mdt_mark_dirty(cpfile);
378 if (!nilfs_cpfile_is_in_first(cpfile, cno)) {
379 count =
380 nilfs_cpfile_block_sub_valid_checkpoints(
381 cpfile, cp_bh, kaddr, nicps);
382 if (count == 0) {
383 /* make hole */
384 kunmap_atomic(kaddr);
385 brelse(cp_bh);
386 ret =
387 nilfs_cpfile_delete_checkpoint_block(
388 cpfile, cno);
389 if (ret == 0)
390 continue;
391 printk(KERN_ERR
392 "%s: cannot delete block\n",
393 __func__);
394 break;
395 }
396 }
397 }
398
399 kunmap_atomic(kaddr);
400 brelse(cp_bh);
401 }
402
403 if (tnicps > 0) {
404 kaddr = kmap_atomic(header_bh->b_page);
405 header = nilfs_cpfile_block_get_header(cpfile, header_bh,
406 kaddr);
407 le64_add_cpu(&header->ch_ncheckpoints, -(u64)tnicps);
408 mark_buffer_dirty(header_bh);
409 nilfs_mdt_mark_dirty(cpfile);
410 kunmap_atomic(kaddr);
411 }
412
413 brelse(header_bh);
414 if (nss > 0)
415 ret = -EBUSY;
416
417 out_sem:
418 up_write(&NILFS_MDT(cpfile)->mi_sem);
419 return ret;
420}
421
422static void nilfs_cpfile_checkpoint_to_cpinfo(struct inode *cpfile,
423 struct nilfs_checkpoint *cp,
424 struct nilfs_cpinfo *ci)
425{
426 ci->ci_flags = le32_to_cpu(cp->cp_flags);
427 ci->ci_cno = le64_to_cpu(cp->cp_cno);
428 ci->ci_create = le64_to_cpu(cp->cp_create);
429 ci->ci_nblk_inc = le64_to_cpu(cp->cp_nblk_inc);
430 ci->ci_inodes_count = le64_to_cpu(cp->cp_inodes_count);
431 ci->ci_blocks_count = le64_to_cpu(cp->cp_blocks_count);
432 ci->ci_next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
433}
434
435static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop,
436 void *buf, unsigned cisz, size_t nci)
437{
438 struct nilfs_checkpoint *cp;
439 struct nilfs_cpinfo *ci = buf;
440 struct buffer_head *bh;
441 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
442 __u64 cur_cno = nilfs_mdt_cno(cpfile), cno = *cnop;
443 void *kaddr;
444 int n, ret;
445 int ncps, i;
446
447 if (cno == 0)
448 return -ENOENT; /* checkpoint number 0 is invalid */
449 down_read(&NILFS_MDT(cpfile)->mi_sem);
450
451 for (n = 0; n < nci; cno += ncps) {
452 ret = nilfs_cpfile_find_checkpoint_block(
453 cpfile, cno, cur_cno - 1, &cno, &bh);
454 if (ret < 0) {
455 if (likely(ret == -ENOENT))
456 break;
457 goto out;
458 }
459 ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, cur_cno);
460
461 kaddr = kmap_atomic(bh->b_page);
462 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
463 for (i = 0; i < ncps && n < nci; i++, cp = (void *)cp + cpsz) {
464 if (!nilfs_checkpoint_invalid(cp)) {
465 nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp,
466 ci);
467 ci = (void *)ci + cisz;
468 n++;
469 }
470 }
471 kunmap_atomic(kaddr);
472 brelse(bh);
473 }
474
475 ret = n;
476 if (n > 0) {
477 ci = (void *)ci - cisz;
478 *cnop = ci->ci_cno + 1;
479 }
480
481 out:
482 up_read(&NILFS_MDT(cpfile)->mi_sem);
483 return ret;
484}
485
486static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
487 void *buf, unsigned cisz, size_t nci)
488{
489 struct buffer_head *bh;
490 struct nilfs_cpfile_header *header;
491 struct nilfs_checkpoint *cp;
492 struct nilfs_cpinfo *ci = buf;
493 __u64 curr = *cnop, next;
494 unsigned long curr_blkoff, next_blkoff;
495 void *kaddr;
496 int n = 0, ret;
497
498 down_read(&NILFS_MDT(cpfile)->mi_sem);
499
500 if (curr == 0) {
501 ret = nilfs_cpfile_get_header_block(cpfile, &bh);
502 if (ret < 0)
503 goto out;
504 kaddr = kmap_atomic(bh->b_page);
505 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
506 curr = le64_to_cpu(header->ch_snapshot_list.ssl_next);
507 kunmap_atomic(kaddr);
508 brelse(bh);
509 if (curr == 0) {
510 ret = 0;
511 goto out;
512 }
513 } else if (unlikely(curr == ~(__u64)0)) {
514 ret = 0;
515 goto out;
516 }
517
518 curr_blkoff = nilfs_cpfile_get_blkoff(cpfile, curr);
519 ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr, 0, &bh);
520 if (unlikely(ret < 0)) {
521 if (ret == -ENOENT)
522 ret = 0; /* No snapshots (started from a hole block) */
523 goto out;
524 }
525 kaddr = kmap_atomic(bh->b_page);
526 while (n < nci) {
527 cp = nilfs_cpfile_block_get_checkpoint(cpfile, curr, bh, kaddr);
528 curr = ~(__u64)0; /* Terminator */
529 if (unlikely(nilfs_checkpoint_invalid(cp) ||
530 !nilfs_checkpoint_snapshot(cp)))
531 break;
532 nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, ci);
533 ci = (void *)ci + cisz;
534 n++;
535 next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
536 if (next == 0)
537 break; /* reach end of the snapshot list */
538
539 next_blkoff = nilfs_cpfile_get_blkoff(cpfile, next);
540 if (curr_blkoff != next_blkoff) {
541 kunmap_atomic(kaddr);
542 brelse(bh);
543 ret = nilfs_cpfile_get_checkpoint_block(cpfile, next,
544 0, &bh);
545 if (unlikely(ret < 0)) {
546 WARN_ON(ret == -ENOENT);
547 goto out;
548 }
549 kaddr = kmap_atomic(bh->b_page);
550 }
551 curr = next;
552 curr_blkoff = next_blkoff;
553 }
554 kunmap_atomic(kaddr);
555 brelse(bh);
556 *cnop = curr;
557 ret = n;
558
559 out:
560 up_read(&NILFS_MDT(cpfile)->mi_sem);
561 return ret;
562}
563
564/**
565 * nilfs_cpfile_get_cpinfo -
566 * @cpfile:
567 * @cno:
568 * @ci:
569 * @nci:
570 */
571
572ssize_t nilfs_cpfile_get_cpinfo(struct inode *cpfile, __u64 *cnop, int mode,
573 void *buf, unsigned cisz, size_t nci)
574{
575 switch (mode) {
576 case NILFS_CHECKPOINT:
577 return nilfs_cpfile_do_get_cpinfo(cpfile, cnop, buf, cisz, nci);
578 case NILFS_SNAPSHOT:
579 return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, buf, cisz, nci);
580 default:
581 return -EINVAL;
582 }
583}
584
585/**
586 * nilfs_cpfile_delete_checkpoint -
587 * @cpfile:
588 * @cno:
589 */
590int nilfs_cpfile_delete_checkpoint(struct inode *cpfile, __u64 cno)
591{
592 struct nilfs_cpinfo ci;
593 __u64 tcno = cno;
594 ssize_t nci;
595
596 nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, sizeof(ci), 1);
597 if (nci < 0)
598 return nci;
599 else if (nci == 0 || ci.ci_cno != cno)
600 return -ENOENT;
601 else if (nilfs_cpinfo_snapshot(&ci))
602 return -EBUSY;
603
604 return nilfs_cpfile_delete_checkpoints(cpfile, cno, cno + 1);
605}
606
607static struct nilfs_snapshot_list *
608nilfs_cpfile_block_get_snapshot_list(const struct inode *cpfile,
609 __u64 cno,
610 struct buffer_head *bh,
611 void *kaddr)
612{
613 struct nilfs_cpfile_header *header;
614 struct nilfs_checkpoint *cp;
615 struct nilfs_snapshot_list *list;
616
617 if (cno != 0) {
618 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
619 list = &cp->cp_snapshot_list;
620 } else {
621 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
622 list = &header->ch_snapshot_list;
623 }
624 return list;
625}
626
627static int nilfs_cpfile_set_snapshot(struct inode *cpfile, __u64 cno)
628{
629 struct buffer_head *header_bh, *curr_bh, *prev_bh, *cp_bh;
630 struct nilfs_cpfile_header *header;
631 struct nilfs_checkpoint *cp;
632 struct nilfs_snapshot_list *list;
633 __u64 curr, prev;
634 unsigned long curr_blkoff, prev_blkoff;
635 void *kaddr;
636 int ret;
637
638 if (cno == 0)
639 return -ENOENT; /* checkpoint number 0 is invalid */
640 down_write(&NILFS_MDT(cpfile)->mi_sem);
641
642 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
643 if (ret < 0)
644 goto out_sem;
645 kaddr = kmap_atomic(cp_bh->b_page);
646 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
647 if (nilfs_checkpoint_invalid(cp)) {
648 ret = -ENOENT;
649 kunmap_atomic(kaddr);
650 goto out_cp;
651 }
652 if (nilfs_checkpoint_snapshot(cp)) {
653 ret = 0;
654 kunmap_atomic(kaddr);
655 goto out_cp;
656 }
657 kunmap_atomic(kaddr);
658
659 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
660 if (ret < 0)
661 goto out_cp;
662 kaddr = kmap_atomic(header_bh->b_page);
663 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
664 list = &header->ch_snapshot_list;
665 curr_bh = header_bh;
666 get_bh(curr_bh);
667 curr = 0;
668 curr_blkoff = 0;
669 prev = le64_to_cpu(list->ssl_prev);
670 while (prev > cno) {
671 prev_blkoff = nilfs_cpfile_get_blkoff(cpfile, prev);
672 curr = prev;
673 if (curr_blkoff != prev_blkoff) {
674 kunmap_atomic(kaddr);
675 brelse(curr_bh);
676 ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr,
677 0, &curr_bh);
678 if (ret < 0)
679 goto out_header;
680 kaddr = kmap_atomic(curr_bh->b_page);
681 }
682 curr_blkoff = prev_blkoff;
683 cp = nilfs_cpfile_block_get_checkpoint(
684 cpfile, curr, curr_bh, kaddr);
685 list = &cp->cp_snapshot_list;
686 prev = le64_to_cpu(list->ssl_prev);
687 }
688 kunmap_atomic(kaddr);
689
690 if (prev != 0) {
691 ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
692 &prev_bh);
693 if (ret < 0)
694 goto out_curr;
695 } else {
696 prev_bh = header_bh;
697 get_bh(prev_bh);
698 }
699
700 kaddr = kmap_atomic(curr_bh->b_page);
701 list = nilfs_cpfile_block_get_snapshot_list(
702 cpfile, curr, curr_bh, kaddr);
703 list->ssl_prev = cpu_to_le64(cno);
704 kunmap_atomic(kaddr);
705
706 kaddr = kmap_atomic(cp_bh->b_page);
707 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
708 cp->cp_snapshot_list.ssl_next = cpu_to_le64(curr);
709 cp->cp_snapshot_list.ssl_prev = cpu_to_le64(prev);
710 nilfs_checkpoint_set_snapshot(cp);
711 kunmap_atomic(kaddr);
712
713 kaddr = kmap_atomic(prev_bh->b_page);
714 list = nilfs_cpfile_block_get_snapshot_list(
715 cpfile, prev, prev_bh, kaddr);
716 list->ssl_next = cpu_to_le64(cno);
717 kunmap_atomic(kaddr);
718
719 kaddr = kmap_atomic(header_bh->b_page);
720 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
721 le64_add_cpu(&header->ch_nsnapshots, 1);
722 kunmap_atomic(kaddr);
723
724 mark_buffer_dirty(prev_bh);
725 mark_buffer_dirty(curr_bh);
726 mark_buffer_dirty(cp_bh);
727 mark_buffer_dirty(header_bh);
728 nilfs_mdt_mark_dirty(cpfile);
729
730 brelse(prev_bh);
731
732 out_curr:
733 brelse(curr_bh);
734
735 out_header:
736 brelse(header_bh);
737
738 out_cp:
739 brelse(cp_bh);
740
741 out_sem:
742 up_write(&NILFS_MDT(cpfile)->mi_sem);
743 return ret;
744}
745
746static int nilfs_cpfile_clear_snapshot(struct inode *cpfile, __u64 cno)
747{
748 struct buffer_head *header_bh, *next_bh, *prev_bh, *cp_bh;
749 struct nilfs_cpfile_header *header;
750 struct nilfs_checkpoint *cp;
751 struct nilfs_snapshot_list *list;
752 __u64 next, prev;
753 void *kaddr;
754 int ret;
755
756 if (cno == 0)
757 return -ENOENT; /* checkpoint number 0 is invalid */
758 down_write(&NILFS_MDT(cpfile)->mi_sem);
759
760 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
761 if (ret < 0)
762 goto out_sem;
763 kaddr = kmap_atomic(cp_bh->b_page);
764 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
765 if (nilfs_checkpoint_invalid(cp)) {
766 ret = -ENOENT;
767 kunmap_atomic(kaddr);
768 goto out_cp;
769 }
770 if (!nilfs_checkpoint_snapshot(cp)) {
771 ret = 0;
772 kunmap_atomic(kaddr);
773 goto out_cp;
774 }
775
776 list = &cp->cp_snapshot_list;
777 next = le64_to_cpu(list->ssl_next);
778 prev = le64_to_cpu(list->ssl_prev);
779 kunmap_atomic(kaddr);
780
781 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
782 if (ret < 0)
783 goto out_cp;
784 if (next != 0) {
785 ret = nilfs_cpfile_get_checkpoint_block(cpfile, next, 0,
786 &next_bh);
787 if (ret < 0)
788 goto out_header;
789 } else {
790 next_bh = header_bh;
791 get_bh(next_bh);
792 }
793 if (prev != 0) {
794 ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
795 &prev_bh);
796 if (ret < 0)
797 goto out_next;
798 } else {
799 prev_bh = header_bh;
800 get_bh(prev_bh);
801 }
802
803 kaddr = kmap_atomic(next_bh->b_page);
804 list = nilfs_cpfile_block_get_snapshot_list(
805 cpfile, next, next_bh, kaddr);
806 list->ssl_prev = cpu_to_le64(prev);
807 kunmap_atomic(kaddr);
808
809 kaddr = kmap_atomic(prev_bh->b_page);
810 list = nilfs_cpfile_block_get_snapshot_list(
811 cpfile, prev, prev_bh, kaddr);
812 list->ssl_next = cpu_to_le64(next);
813 kunmap_atomic(kaddr);
814
815 kaddr = kmap_atomic(cp_bh->b_page);
816 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
817 cp->cp_snapshot_list.ssl_next = cpu_to_le64(0);
818 cp->cp_snapshot_list.ssl_prev = cpu_to_le64(0);
819 nilfs_checkpoint_clear_snapshot(cp);
820 kunmap_atomic(kaddr);
821
822 kaddr = kmap_atomic(header_bh->b_page);
823 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
824 le64_add_cpu(&header->ch_nsnapshots, -1);
825 kunmap_atomic(kaddr);
826
827 mark_buffer_dirty(next_bh);
828 mark_buffer_dirty(prev_bh);
829 mark_buffer_dirty(cp_bh);
830 mark_buffer_dirty(header_bh);
831 nilfs_mdt_mark_dirty(cpfile);
832
833 brelse(prev_bh);
834
835 out_next:
836 brelse(next_bh);
837
838 out_header:
839 brelse(header_bh);
840
841 out_cp:
842 brelse(cp_bh);
843
844 out_sem:
845 up_write(&NILFS_MDT(cpfile)->mi_sem);
846 return ret;
847}
848
849/**
850 * nilfs_cpfile_is_snapshot -
851 * @cpfile: inode of checkpoint file
852 * @cno: checkpoint number
853 *
854 * Description:
855 *
856 * Return Value: On success, 1 is returned if the checkpoint specified by
857 * @cno is a snapshot, or 0 if not. On error, one of the following negative
858 * error codes is returned.
859 *
860 * %-EIO - I/O error.
861 *
862 * %-ENOMEM - Insufficient amount of memory available.
863 *
864 * %-ENOENT - No such checkpoint.
865 */
866int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
867{
868 struct buffer_head *bh;
869 struct nilfs_checkpoint *cp;
870 void *kaddr;
871 int ret;
872
873 /* CP number is invalid if it's zero or larger than the
874 largest exist one.*/
875 if (cno == 0 || cno >= nilfs_mdt_cno(cpfile))
876 return -ENOENT;
877 down_read(&NILFS_MDT(cpfile)->mi_sem);
878
879 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
880 if (ret < 0)
881 goto out;
882 kaddr = kmap_atomic(bh->b_page);
883 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
884 if (nilfs_checkpoint_invalid(cp))
885 ret = -ENOENT;
886 else
887 ret = nilfs_checkpoint_snapshot(cp);
888 kunmap_atomic(kaddr);
889 brelse(bh);
890
891 out:
892 up_read(&NILFS_MDT(cpfile)->mi_sem);
893 return ret;
894}
895
896/**
897 * nilfs_cpfile_change_cpmode - change checkpoint mode
898 * @cpfile: inode of checkpoint file
899 * @cno: checkpoint number
900 * @status: mode of checkpoint
901 *
902 * Description: nilfs_change_cpmode() changes the mode of the checkpoint
903 * specified by @cno. The mode @mode is NILFS_CHECKPOINT or NILFS_SNAPSHOT.
904 *
905 * Return Value: On success, 0 is returned. On error, one of the following
906 * negative error codes is returned.
907 *
908 * %-EIO - I/O error.
909 *
910 * %-ENOMEM - Insufficient amount of memory available.
911 *
912 * %-ENOENT - No such checkpoint.
913 */
914int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode)
915{
916 int ret;
917
918 switch (mode) {
919 case NILFS_CHECKPOINT:
920 if (nilfs_checkpoint_is_mounted(cpfile->i_sb, cno))
921 /*
922 * Current implementation does not have to protect
923 * plain read-only mounts since they are exclusive
924 * with a read/write mount and are protected from the
925 * cleaner.
926 */
927 ret = -EBUSY;
928 else
929 ret = nilfs_cpfile_clear_snapshot(cpfile, cno);
930 return ret;
931 case NILFS_SNAPSHOT:
932 return nilfs_cpfile_set_snapshot(cpfile, cno);
933 default:
934 return -EINVAL;
935 }
936}
937
938/**
939 * nilfs_cpfile_get_stat - get checkpoint statistics
940 * @cpfile: inode of checkpoint file
941 * @stat: pointer to a structure of checkpoint statistics
942 *
943 * Description: nilfs_cpfile_get_stat() returns information about checkpoints.
944 *
945 * Return Value: On success, 0 is returned, and checkpoints information is
946 * stored in the place pointed by @stat. On error, one of the following
947 * negative error codes is returned.
948 *
949 * %-EIO - I/O error.
950 *
951 * %-ENOMEM - Insufficient amount of memory available.
952 */
953int nilfs_cpfile_get_stat(struct inode *cpfile, struct nilfs_cpstat *cpstat)
954{
955 struct buffer_head *bh;
956 struct nilfs_cpfile_header *header;
957 void *kaddr;
958 int ret;
959
960 down_read(&NILFS_MDT(cpfile)->mi_sem);
961
962 ret = nilfs_cpfile_get_header_block(cpfile, &bh);
963 if (ret < 0)
964 goto out_sem;
965 kaddr = kmap_atomic(bh->b_page);
966 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
967 cpstat->cs_cno = nilfs_mdt_cno(cpfile);
968 cpstat->cs_ncps = le64_to_cpu(header->ch_ncheckpoints);
969 cpstat->cs_nsss = le64_to_cpu(header->ch_nsnapshots);
970 kunmap_atomic(kaddr);
971 brelse(bh);
972
973 out_sem:
974 up_read(&NILFS_MDT(cpfile)->mi_sem);
975 return ret;
976}
977
978/**
979 * nilfs_cpfile_read - read or get cpfile inode
980 * @sb: super block instance
981 * @cpsize: size of a checkpoint entry
982 * @raw_inode: on-disk cpfile inode
983 * @inodep: buffer to store the inode
984 */
985int nilfs_cpfile_read(struct super_block *sb, size_t cpsize,
986 struct nilfs_inode *raw_inode, struct inode **inodep)
987{
988 struct inode *cpfile;
989 int err;
990
991 if (cpsize > sb->s_blocksize) {
992 printk(KERN_ERR
993 "NILFS: too large checkpoint size: %zu bytes.\n",
994 cpsize);
995 return -EINVAL;
996 } else if (cpsize < NILFS_MIN_CHECKPOINT_SIZE) {
997 printk(KERN_ERR
998 "NILFS: too small checkpoint size: %zu bytes.\n",
999 cpsize);
1000 return -EINVAL;
1001 }
1002
1003 cpfile = nilfs_iget_locked(sb, NULL, NILFS_CPFILE_INO);
1004 if (unlikely(!cpfile))
1005 return -ENOMEM;
1006 if (!(cpfile->i_state & I_NEW))
1007 goto out;
1008
1009 err = nilfs_mdt_init(cpfile, NILFS_MDT_GFP, 0);
1010 if (err)
1011 goto failed;
1012
1013 nilfs_mdt_set_entry_size(cpfile, cpsize,
1014 sizeof(struct nilfs_cpfile_header));
1015
1016 err = nilfs_read_inode_common(cpfile, raw_inode);
1017 if (err)
1018 goto failed;
1019
1020 unlock_new_inode(cpfile);
1021 out:
1022 *inodep = cpfile;
1023 return 0;
1024 failed:
1025 iget_failed(cpfile);
1026 return err;
1027}
1/*
2 * cpfile.c - NILFS checkpoint file.
3 *
4 * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * Written by Koji Sato.
17 */
18
19#include <linux/kernel.h>
20#include <linux/fs.h>
21#include <linux/string.h>
22#include <linux/buffer_head.h>
23#include <linux/errno.h>
24#include "mdt.h"
25#include "cpfile.h"
26
27
28static inline unsigned long
29nilfs_cpfile_checkpoints_per_block(const struct inode *cpfile)
30{
31 return NILFS_MDT(cpfile)->mi_entries_per_block;
32}
33
34/* block number from the beginning of the file */
35static unsigned long
36nilfs_cpfile_get_blkoff(const struct inode *cpfile, __u64 cno)
37{
38 __u64 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
39
40 do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile));
41 return (unsigned long)tcno;
42}
43
44/* offset in block */
45static unsigned long
46nilfs_cpfile_get_offset(const struct inode *cpfile, __u64 cno)
47{
48 __u64 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
49
50 return do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile));
51}
52
53static __u64 nilfs_cpfile_first_checkpoint_in_block(const struct inode *cpfile,
54 unsigned long blkoff)
55{
56 return (__u64)nilfs_cpfile_checkpoints_per_block(cpfile) * blkoff
57 + 1 - NILFS_MDT(cpfile)->mi_first_entry_offset;
58}
59
60static unsigned long
61nilfs_cpfile_checkpoints_in_block(const struct inode *cpfile,
62 __u64 curr,
63 __u64 max)
64{
65 return min_t(__u64,
66 nilfs_cpfile_checkpoints_per_block(cpfile) -
67 nilfs_cpfile_get_offset(cpfile, curr),
68 max - curr);
69}
70
71static inline int nilfs_cpfile_is_in_first(const struct inode *cpfile,
72 __u64 cno)
73{
74 return nilfs_cpfile_get_blkoff(cpfile, cno) == 0;
75}
76
77static unsigned int
78nilfs_cpfile_block_add_valid_checkpoints(const struct inode *cpfile,
79 struct buffer_head *bh,
80 void *kaddr,
81 unsigned int n)
82{
83 struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
84 unsigned int count;
85
86 count = le32_to_cpu(cp->cp_checkpoints_count) + n;
87 cp->cp_checkpoints_count = cpu_to_le32(count);
88 return count;
89}
90
91static unsigned int
92nilfs_cpfile_block_sub_valid_checkpoints(const struct inode *cpfile,
93 struct buffer_head *bh,
94 void *kaddr,
95 unsigned int n)
96{
97 struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
98 unsigned int count;
99
100 WARN_ON(le32_to_cpu(cp->cp_checkpoints_count) < n);
101 count = le32_to_cpu(cp->cp_checkpoints_count) - n;
102 cp->cp_checkpoints_count = cpu_to_le32(count);
103 return count;
104}
105
106static inline struct nilfs_cpfile_header *
107nilfs_cpfile_block_get_header(const struct inode *cpfile,
108 struct buffer_head *bh,
109 void *kaddr)
110{
111 return kaddr + bh_offset(bh);
112}
113
114static struct nilfs_checkpoint *
115nilfs_cpfile_block_get_checkpoint(const struct inode *cpfile, __u64 cno,
116 struct buffer_head *bh,
117 void *kaddr)
118{
119 return kaddr + bh_offset(bh) + nilfs_cpfile_get_offset(cpfile, cno) *
120 NILFS_MDT(cpfile)->mi_entry_size;
121}
122
123static void nilfs_cpfile_block_init(struct inode *cpfile,
124 struct buffer_head *bh,
125 void *kaddr)
126{
127 struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
128 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
129 int n = nilfs_cpfile_checkpoints_per_block(cpfile);
130
131 while (n-- > 0) {
132 nilfs_checkpoint_set_invalid(cp);
133 cp = (void *)cp + cpsz;
134 }
135}
136
137static inline int nilfs_cpfile_get_header_block(struct inode *cpfile,
138 struct buffer_head **bhp)
139{
140 return nilfs_mdt_get_block(cpfile, 0, 0, NULL, bhp);
141}
142
143static inline int nilfs_cpfile_get_checkpoint_block(struct inode *cpfile,
144 __u64 cno,
145 int create,
146 struct buffer_head **bhp)
147{
148 return nilfs_mdt_get_block(cpfile,
149 nilfs_cpfile_get_blkoff(cpfile, cno),
150 create, nilfs_cpfile_block_init, bhp);
151}
152
153/**
154 * nilfs_cpfile_find_checkpoint_block - find and get a buffer on cpfile
155 * @cpfile: inode of cpfile
156 * @start_cno: start checkpoint number (inclusive)
157 * @end_cno: end checkpoint number (inclusive)
158 * @cnop: place to store the next checkpoint number
159 * @bhp: place to store a pointer to buffer_head struct
160 *
161 * Return Value: On success, it returns 0. On error, the following negative
162 * error code is returned.
163 *
164 * %-ENOMEM - Insufficient memory available.
165 *
166 * %-EIO - I/O error
167 *
168 * %-ENOENT - no block exists in the range.
169 */
170static int nilfs_cpfile_find_checkpoint_block(struct inode *cpfile,
171 __u64 start_cno, __u64 end_cno,
172 __u64 *cnop,
173 struct buffer_head **bhp)
174{
175 unsigned long start, end, blkoff;
176 int ret;
177
178 if (unlikely(start_cno > end_cno))
179 return -ENOENT;
180
181 start = nilfs_cpfile_get_blkoff(cpfile, start_cno);
182 end = nilfs_cpfile_get_blkoff(cpfile, end_cno);
183
184 ret = nilfs_mdt_find_block(cpfile, start, end, &blkoff, bhp);
185 if (!ret)
186 *cnop = (blkoff == start) ? start_cno :
187 nilfs_cpfile_first_checkpoint_in_block(cpfile, blkoff);
188 return ret;
189}
190
191static inline int nilfs_cpfile_delete_checkpoint_block(struct inode *cpfile,
192 __u64 cno)
193{
194 return nilfs_mdt_delete_block(cpfile,
195 nilfs_cpfile_get_blkoff(cpfile, cno));
196}
197
198/**
199 * nilfs_cpfile_get_checkpoint - get a checkpoint
200 * @cpfile: inode of checkpoint file
201 * @cno: checkpoint number
202 * @create: create flag
203 * @cpp: pointer to a checkpoint
204 * @bhp: pointer to a buffer head
205 *
206 * Description: nilfs_cpfile_get_checkpoint() acquires the checkpoint
207 * specified by @cno. A new checkpoint will be created if @cno is the current
208 * checkpoint number and @create is nonzero.
209 *
210 * Return Value: On success, 0 is returned, and the checkpoint and the
211 * buffer head of the buffer on which the checkpoint is located are stored in
212 * the place pointed by @cpp and @bhp, respectively. On error, one of the
213 * following negative error codes is returned.
214 *
215 * %-EIO - I/O error.
216 *
217 * %-ENOMEM - Insufficient amount of memory available.
218 *
219 * %-ENOENT - No such checkpoint.
220 *
221 * %-EINVAL - invalid checkpoint.
222 */
223int nilfs_cpfile_get_checkpoint(struct inode *cpfile,
224 __u64 cno,
225 int create,
226 struct nilfs_checkpoint **cpp,
227 struct buffer_head **bhp)
228{
229 struct buffer_head *header_bh, *cp_bh;
230 struct nilfs_cpfile_header *header;
231 struct nilfs_checkpoint *cp;
232 void *kaddr;
233 int ret;
234
235 if (unlikely(cno < 1 || cno > nilfs_mdt_cno(cpfile) ||
236 (cno < nilfs_mdt_cno(cpfile) && create)))
237 return -EINVAL;
238
239 down_write(&NILFS_MDT(cpfile)->mi_sem);
240
241 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
242 if (ret < 0)
243 goto out_sem;
244 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, create, &cp_bh);
245 if (ret < 0)
246 goto out_header;
247 kaddr = kmap(cp_bh->b_page);
248 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
249 if (nilfs_checkpoint_invalid(cp)) {
250 if (!create) {
251 kunmap(cp_bh->b_page);
252 brelse(cp_bh);
253 ret = -ENOENT;
254 goto out_header;
255 }
256 /* a newly-created checkpoint */
257 nilfs_checkpoint_clear_invalid(cp);
258 if (!nilfs_cpfile_is_in_first(cpfile, cno))
259 nilfs_cpfile_block_add_valid_checkpoints(cpfile, cp_bh,
260 kaddr, 1);
261 mark_buffer_dirty(cp_bh);
262
263 kaddr = kmap_atomic(header_bh->b_page);
264 header = nilfs_cpfile_block_get_header(cpfile, header_bh,
265 kaddr);
266 le64_add_cpu(&header->ch_ncheckpoints, 1);
267 kunmap_atomic(kaddr);
268 mark_buffer_dirty(header_bh);
269 nilfs_mdt_mark_dirty(cpfile);
270 }
271
272 if (cpp != NULL)
273 *cpp = cp;
274 *bhp = cp_bh;
275
276 out_header:
277 brelse(header_bh);
278
279 out_sem:
280 up_write(&NILFS_MDT(cpfile)->mi_sem);
281 return ret;
282}
283
284/**
285 * nilfs_cpfile_put_checkpoint - put a checkpoint
286 * @cpfile: inode of checkpoint file
287 * @cno: checkpoint number
288 * @bh: buffer head
289 *
290 * Description: nilfs_cpfile_put_checkpoint() releases the checkpoint
291 * specified by @cno. @bh must be the buffer head which has been returned by
292 * a previous call to nilfs_cpfile_get_checkpoint() with @cno.
293 */
294void nilfs_cpfile_put_checkpoint(struct inode *cpfile, __u64 cno,
295 struct buffer_head *bh)
296{
297 kunmap(bh->b_page);
298 brelse(bh);
299}
300
301/**
302 * nilfs_cpfile_delete_checkpoints - delete checkpoints
303 * @cpfile: inode of checkpoint file
304 * @start: start checkpoint number
305 * @end: end checkpoint numer
306 *
307 * Description: nilfs_cpfile_delete_checkpoints() deletes the checkpoints in
308 * the period from @start to @end, excluding @end itself. The checkpoints
309 * which have been already deleted are ignored.
310 *
311 * Return Value: On success, 0 is returned. On error, one of the following
312 * negative error codes is returned.
313 *
314 * %-EIO - I/O error.
315 *
316 * %-ENOMEM - Insufficient amount of memory available.
317 *
318 * %-EINVAL - invalid checkpoints.
319 */
320int nilfs_cpfile_delete_checkpoints(struct inode *cpfile,
321 __u64 start,
322 __u64 end)
323{
324 struct buffer_head *header_bh, *cp_bh;
325 struct nilfs_cpfile_header *header;
326 struct nilfs_checkpoint *cp;
327 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
328 __u64 cno;
329 void *kaddr;
330 unsigned long tnicps;
331 int ret, ncps, nicps, nss, count, i;
332
333 if (unlikely(start == 0 || start > end)) {
334 nilfs_msg(cpfile->i_sb, KERN_ERR,
335 "cannot delete checkpoints: invalid range [%llu, %llu)",
336 (unsigned long long)start, (unsigned long long)end);
337 return -EINVAL;
338 }
339
340 down_write(&NILFS_MDT(cpfile)->mi_sem);
341
342 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
343 if (ret < 0)
344 goto out_sem;
345 tnicps = 0;
346 nss = 0;
347
348 for (cno = start; cno < end; cno += ncps) {
349 ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, end);
350 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
351 if (ret < 0) {
352 if (ret != -ENOENT)
353 break;
354 /* skip hole */
355 ret = 0;
356 continue;
357 }
358
359 kaddr = kmap_atomic(cp_bh->b_page);
360 cp = nilfs_cpfile_block_get_checkpoint(
361 cpfile, cno, cp_bh, kaddr);
362 nicps = 0;
363 for (i = 0; i < ncps; i++, cp = (void *)cp + cpsz) {
364 if (nilfs_checkpoint_snapshot(cp)) {
365 nss++;
366 } else if (!nilfs_checkpoint_invalid(cp)) {
367 nilfs_checkpoint_set_invalid(cp);
368 nicps++;
369 }
370 }
371 if (nicps > 0) {
372 tnicps += nicps;
373 mark_buffer_dirty(cp_bh);
374 nilfs_mdt_mark_dirty(cpfile);
375 if (!nilfs_cpfile_is_in_first(cpfile, cno)) {
376 count =
377 nilfs_cpfile_block_sub_valid_checkpoints(
378 cpfile, cp_bh, kaddr, nicps);
379 if (count == 0) {
380 /* make hole */
381 kunmap_atomic(kaddr);
382 brelse(cp_bh);
383 ret =
384 nilfs_cpfile_delete_checkpoint_block(
385 cpfile, cno);
386 if (ret == 0)
387 continue;
388 nilfs_msg(cpfile->i_sb, KERN_ERR,
389 "error %d deleting checkpoint block",
390 ret);
391 break;
392 }
393 }
394 }
395
396 kunmap_atomic(kaddr);
397 brelse(cp_bh);
398 }
399
400 if (tnicps > 0) {
401 kaddr = kmap_atomic(header_bh->b_page);
402 header = nilfs_cpfile_block_get_header(cpfile, header_bh,
403 kaddr);
404 le64_add_cpu(&header->ch_ncheckpoints, -(u64)tnicps);
405 mark_buffer_dirty(header_bh);
406 nilfs_mdt_mark_dirty(cpfile);
407 kunmap_atomic(kaddr);
408 }
409
410 brelse(header_bh);
411 if (nss > 0)
412 ret = -EBUSY;
413
414 out_sem:
415 up_write(&NILFS_MDT(cpfile)->mi_sem);
416 return ret;
417}
418
419static void nilfs_cpfile_checkpoint_to_cpinfo(struct inode *cpfile,
420 struct nilfs_checkpoint *cp,
421 struct nilfs_cpinfo *ci)
422{
423 ci->ci_flags = le32_to_cpu(cp->cp_flags);
424 ci->ci_cno = le64_to_cpu(cp->cp_cno);
425 ci->ci_create = le64_to_cpu(cp->cp_create);
426 ci->ci_nblk_inc = le64_to_cpu(cp->cp_nblk_inc);
427 ci->ci_inodes_count = le64_to_cpu(cp->cp_inodes_count);
428 ci->ci_blocks_count = le64_to_cpu(cp->cp_blocks_count);
429 ci->ci_next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
430}
431
432static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop,
433 void *buf, unsigned int cisz,
434 size_t nci)
435{
436 struct nilfs_checkpoint *cp;
437 struct nilfs_cpinfo *ci = buf;
438 struct buffer_head *bh;
439 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
440 __u64 cur_cno = nilfs_mdt_cno(cpfile), cno = *cnop;
441 void *kaddr;
442 int n, ret;
443 int ncps, i;
444
445 if (cno == 0)
446 return -ENOENT; /* checkpoint number 0 is invalid */
447 down_read(&NILFS_MDT(cpfile)->mi_sem);
448
449 for (n = 0; n < nci; cno += ncps) {
450 ret = nilfs_cpfile_find_checkpoint_block(
451 cpfile, cno, cur_cno - 1, &cno, &bh);
452 if (ret < 0) {
453 if (likely(ret == -ENOENT))
454 break;
455 goto out;
456 }
457 ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, cur_cno);
458
459 kaddr = kmap_atomic(bh->b_page);
460 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
461 for (i = 0; i < ncps && n < nci; i++, cp = (void *)cp + cpsz) {
462 if (!nilfs_checkpoint_invalid(cp)) {
463 nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp,
464 ci);
465 ci = (void *)ci + cisz;
466 n++;
467 }
468 }
469 kunmap_atomic(kaddr);
470 brelse(bh);
471 }
472
473 ret = n;
474 if (n > 0) {
475 ci = (void *)ci - cisz;
476 *cnop = ci->ci_cno + 1;
477 }
478
479 out:
480 up_read(&NILFS_MDT(cpfile)->mi_sem);
481 return ret;
482}
483
484static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
485 void *buf, unsigned int cisz,
486 size_t nci)
487{
488 struct buffer_head *bh;
489 struct nilfs_cpfile_header *header;
490 struct nilfs_checkpoint *cp;
491 struct nilfs_cpinfo *ci = buf;
492 __u64 curr = *cnop, next;
493 unsigned long curr_blkoff, next_blkoff;
494 void *kaddr;
495 int n = 0, ret;
496
497 down_read(&NILFS_MDT(cpfile)->mi_sem);
498
499 if (curr == 0) {
500 ret = nilfs_cpfile_get_header_block(cpfile, &bh);
501 if (ret < 0)
502 goto out;
503 kaddr = kmap_atomic(bh->b_page);
504 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
505 curr = le64_to_cpu(header->ch_snapshot_list.ssl_next);
506 kunmap_atomic(kaddr);
507 brelse(bh);
508 if (curr == 0) {
509 ret = 0;
510 goto out;
511 }
512 } else if (unlikely(curr == ~(__u64)0)) {
513 ret = 0;
514 goto out;
515 }
516
517 curr_blkoff = nilfs_cpfile_get_blkoff(cpfile, curr);
518 ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr, 0, &bh);
519 if (unlikely(ret < 0)) {
520 if (ret == -ENOENT)
521 ret = 0; /* No snapshots (started from a hole block) */
522 goto out;
523 }
524 kaddr = kmap_atomic(bh->b_page);
525 while (n < nci) {
526 cp = nilfs_cpfile_block_get_checkpoint(cpfile, curr, bh, kaddr);
527 curr = ~(__u64)0; /* Terminator */
528 if (unlikely(nilfs_checkpoint_invalid(cp) ||
529 !nilfs_checkpoint_snapshot(cp)))
530 break;
531 nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, ci);
532 ci = (void *)ci + cisz;
533 n++;
534 next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
535 if (next == 0)
536 break; /* reach end of the snapshot list */
537
538 next_blkoff = nilfs_cpfile_get_blkoff(cpfile, next);
539 if (curr_blkoff != next_blkoff) {
540 kunmap_atomic(kaddr);
541 brelse(bh);
542 ret = nilfs_cpfile_get_checkpoint_block(cpfile, next,
543 0, &bh);
544 if (unlikely(ret < 0)) {
545 WARN_ON(ret == -ENOENT);
546 goto out;
547 }
548 kaddr = kmap_atomic(bh->b_page);
549 }
550 curr = next;
551 curr_blkoff = next_blkoff;
552 }
553 kunmap_atomic(kaddr);
554 brelse(bh);
555 *cnop = curr;
556 ret = n;
557
558 out:
559 up_read(&NILFS_MDT(cpfile)->mi_sem);
560 return ret;
561}
562
563/**
564 * nilfs_cpfile_get_cpinfo -
565 * @cpfile:
566 * @cno:
567 * @ci:
568 * @nci:
569 */
570
571ssize_t nilfs_cpfile_get_cpinfo(struct inode *cpfile, __u64 *cnop, int mode,
572 void *buf, unsigned int cisz, size_t nci)
573{
574 switch (mode) {
575 case NILFS_CHECKPOINT:
576 return nilfs_cpfile_do_get_cpinfo(cpfile, cnop, buf, cisz, nci);
577 case NILFS_SNAPSHOT:
578 return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, buf, cisz, nci);
579 default:
580 return -EINVAL;
581 }
582}
583
584/**
585 * nilfs_cpfile_delete_checkpoint -
586 * @cpfile:
587 * @cno:
588 */
589int nilfs_cpfile_delete_checkpoint(struct inode *cpfile, __u64 cno)
590{
591 struct nilfs_cpinfo ci;
592 __u64 tcno = cno;
593 ssize_t nci;
594
595 nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, sizeof(ci), 1);
596 if (nci < 0)
597 return nci;
598 else if (nci == 0 || ci.ci_cno != cno)
599 return -ENOENT;
600 else if (nilfs_cpinfo_snapshot(&ci))
601 return -EBUSY;
602
603 return nilfs_cpfile_delete_checkpoints(cpfile, cno, cno + 1);
604}
605
606static struct nilfs_snapshot_list *
607nilfs_cpfile_block_get_snapshot_list(const struct inode *cpfile,
608 __u64 cno,
609 struct buffer_head *bh,
610 void *kaddr)
611{
612 struct nilfs_cpfile_header *header;
613 struct nilfs_checkpoint *cp;
614 struct nilfs_snapshot_list *list;
615
616 if (cno != 0) {
617 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
618 list = &cp->cp_snapshot_list;
619 } else {
620 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
621 list = &header->ch_snapshot_list;
622 }
623 return list;
624}
625
626static int nilfs_cpfile_set_snapshot(struct inode *cpfile, __u64 cno)
627{
628 struct buffer_head *header_bh, *curr_bh, *prev_bh, *cp_bh;
629 struct nilfs_cpfile_header *header;
630 struct nilfs_checkpoint *cp;
631 struct nilfs_snapshot_list *list;
632 __u64 curr, prev;
633 unsigned long curr_blkoff, prev_blkoff;
634 void *kaddr;
635 int ret;
636
637 if (cno == 0)
638 return -ENOENT; /* checkpoint number 0 is invalid */
639 down_write(&NILFS_MDT(cpfile)->mi_sem);
640
641 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
642 if (ret < 0)
643 goto out_sem;
644 kaddr = kmap_atomic(cp_bh->b_page);
645 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
646 if (nilfs_checkpoint_invalid(cp)) {
647 ret = -ENOENT;
648 kunmap_atomic(kaddr);
649 goto out_cp;
650 }
651 if (nilfs_checkpoint_snapshot(cp)) {
652 ret = 0;
653 kunmap_atomic(kaddr);
654 goto out_cp;
655 }
656 kunmap_atomic(kaddr);
657
658 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
659 if (ret < 0)
660 goto out_cp;
661 kaddr = kmap_atomic(header_bh->b_page);
662 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
663 list = &header->ch_snapshot_list;
664 curr_bh = header_bh;
665 get_bh(curr_bh);
666 curr = 0;
667 curr_blkoff = 0;
668 prev = le64_to_cpu(list->ssl_prev);
669 while (prev > cno) {
670 prev_blkoff = nilfs_cpfile_get_blkoff(cpfile, prev);
671 curr = prev;
672 if (curr_blkoff != prev_blkoff) {
673 kunmap_atomic(kaddr);
674 brelse(curr_bh);
675 ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr,
676 0, &curr_bh);
677 if (ret < 0)
678 goto out_header;
679 kaddr = kmap_atomic(curr_bh->b_page);
680 }
681 curr_blkoff = prev_blkoff;
682 cp = nilfs_cpfile_block_get_checkpoint(
683 cpfile, curr, curr_bh, kaddr);
684 list = &cp->cp_snapshot_list;
685 prev = le64_to_cpu(list->ssl_prev);
686 }
687 kunmap_atomic(kaddr);
688
689 if (prev != 0) {
690 ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
691 &prev_bh);
692 if (ret < 0)
693 goto out_curr;
694 } else {
695 prev_bh = header_bh;
696 get_bh(prev_bh);
697 }
698
699 kaddr = kmap_atomic(curr_bh->b_page);
700 list = nilfs_cpfile_block_get_snapshot_list(
701 cpfile, curr, curr_bh, kaddr);
702 list->ssl_prev = cpu_to_le64(cno);
703 kunmap_atomic(kaddr);
704
705 kaddr = kmap_atomic(cp_bh->b_page);
706 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
707 cp->cp_snapshot_list.ssl_next = cpu_to_le64(curr);
708 cp->cp_snapshot_list.ssl_prev = cpu_to_le64(prev);
709 nilfs_checkpoint_set_snapshot(cp);
710 kunmap_atomic(kaddr);
711
712 kaddr = kmap_atomic(prev_bh->b_page);
713 list = nilfs_cpfile_block_get_snapshot_list(
714 cpfile, prev, prev_bh, kaddr);
715 list->ssl_next = cpu_to_le64(cno);
716 kunmap_atomic(kaddr);
717
718 kaddr = kmap_atomic(header_bh->b_page);
719 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
720 le64_add_cpu(&header->ch_nsnapshots, 1);
721 kunmap_atomic(kaddr);
722
723 mark_buffer_dirty(prev_bh);
724 mark_buffer_dirty(curr_bh);
725 mark_buffer_dirty(cp_bh);
726 mark_buffer_dirty(header_bh);
727 nilfs_mdt_mark_dirty(cpfile);
728
729 brelse(prev_bh);
730
731 out_curr:
732 brelse(curr_bh);
733
734 out_header:
735 brelse(header_bh);
736
737 out_cp:
738 brelse(cp_bh);
739
740 out_sem:
741 up_write(&NILFS_MDT(cpfile)->mi_sem);
742 return ret;
743}
744
745static int nilfs_cpfile_clear_snapshot(struct inode *cpfile, __u64 cno)
746{
747 struct buffer_head *header_bh, *next_bh, *prev_bh, *cp_bh;
748 struct nilfs_cpfile_header *header;
749 struct nilfs_checkpoint *cp;
750 struct nilfs_snapshot_list *list;
751 __u64 next, prev;
752 void *kaddr;
753 int ret;
754
755 if (cno == 0)
756 return -ENOENT; /* checkpoint number 0 is invalid */
757 down_write(&NILFS_MDT(cpfile)->mi_sem);
758
759 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
760 if (ret < 0)
761 goto out_sem;
762 kaddr = kmap_atomic(cp_bh->b_page);
763 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
764 if (nilfs_checkpoint_invalid(cp)) {
765 ret = -ENOENT;
766 kunmap_atomic(kaddr);
767 goto out_cp;
768 }
769 if (!nilfs_checkpoint_snapshot(cp)) {
770 ret = 0;
771 kunmap_atomic(kaddr);
772 goto out_cp;
773 }
774
775 list = &cp->cp_snapshot_list;
776 next = le64_to_cpu(list->ssl_next);
777 prev = le64_to_cpu(list->ssl_prev);
778 kunmap_atomic(kaddr);
779
780 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
781 if (ret < 0)
782 goto out_cp;
783 if (next != 0) {
784 ret = nilfs_cpfile_get_checkpoint_block(cpfile, next, 0,
785 &next_bh);
786 if (ret < 0)
787 goto out_header;
788 } else {
789 next_bh = header_bh;
790 get_bh(next_bh);
791 }
792 if (prev != 0) {
793 ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
794 &prev_bh);
795 if (ret < 0)
796 goto out_next;
797 } else {
798 prev_bh = header_bh;
799 get_bh(prev_bh);
800 }
801
802 kaddr = kmap_atomic(next_bh->b_page);
803 list = nilfs_cpfile_block_get_snapshot_list(
804 cpfile, next, next_bh, kaddr);
805 list->ssl_prev = cpu_to_le64(prev);
806 kunmap_atomic(kaddr);
807
808 kaddr = kmap_atomic(prev_bh->b_page);
809 list = nilfs_cpfile_block_get_snapshot_list(
810 cpfile, prev, prev_bh, kaddr);
811 list->ssl_next = cpu_to_le64(next);
812 kunmap_atomic(kaddr);
813
814 kaddr = kmap_atomic(cp_bh->b_page);
815 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
816 cp->cp_snapshot_list.ssl_next = cpu_to_le64(0);
817 cp->cp_snapshot_list.ssl_prev = cpu_to_le64(0);
818 nilfs_checkpoint_clear_snapshot(cp);
819 kunmap_atomic(kaddr);
820
821 kaddr = kmap_atomic(header_bh->b_page);
822 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
823 le64_add_cpu(&header->ch_nsnapshots, -1);
824 kunmap_atomic(kaddr);
825
826 mark_buffer_dirty(next_bh);
827 mark_buffer_dirty(prev_bh);
828 mark_buffer_dirty(cp_bh);
829 mark_buffer_dirty(header_bh);
830 nilfs_mdt_mark_dirty(cpfile);
831
832 brelse(prev_bh);
833
834 out_next:
835 brelse(next_bh);
836
837 out_header:
838 brelse(header_bh);
839
840 out_cp:
841 brelse(cp_bh);
842
843 out_sem:
844 up_write(&NILFS_MDT(cpfile)->mi_sem);
845 return ret;
846}
847
848/**
849 * nilfs_cpfile_is_snapshot -
850 * @cpfile: inode of checkpoint file
851 * @cno: checkpoint number
852 *
853 * Description:
854 *
855 * Return Value: On success, 1 is returned if the checkpoint specified by
856 * @cno is a snapshot, or 0 if not. On error, one of the following negative
857 * error codes is returned.
858 *
859 * %-EIO - I/O error.
860 *
861 * %-ENOMEM - Insufficient amount of memory available.
862 *
863 * %-ENOENT - No such checkpoint.
864 */
865int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
866{
867 struct buffer_head *bh;
868 struct nilfs_checkpoint *cp;
869 void *kaddr;
870 int ret;
871
872 /*
873 * CP number is invalid if it's zero or larger than the
874 * largest existing one.
875 */
876 if (cno == 0 || cno >= nilfs_mdt_cno(cpfile))
877 return -ENOENT;
878 down_read(&NILFS_MDT(cpfile)->mi_sem);
879
880 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
881 if (ret < 0)
882 goto out;
883 kaddr = kmap_atomic(bh->b_page);
884 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
885 if (nilfs_checkpoint_invalid(cp))
886 ret = -ENOENT;
887 else
888 ret = nilfs_checkpoint_snapshot(cp);
889 kunmap_atomic(kaddr);
890 brelse(bh);
891
892 out:
893 up_read(&NILFS_MDT(cpfile)->mi_sem);
894 return ret;
895}
896
897/**
898 * nilfs_cpfile_change_cpmode - change checkpoint mode
899 * @cpfile: inode of checkpoint file
900 * @cno: checkpoint number
901 * @status: mode of checkpoint
902 *
903 * Description: nilfs_change_cpmode() changes the mode of the checkpoint
904 * specified by @cno. The mode @mode is NILFS_CHECKPOINT or NILFS_SNAPSHOT.
905 *
906 * Return Value: On success, 0 is returned. On error, one of the following
907 * negative error codes is returned.
908 *
909 * %-EIO - I/O error.
910 *
911 * %-ENOMEM - Insufficient amount of memory available.
912 *
913 * %-ENOENT - No such checkpoint.
914 */
915int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode)
916{
917 int ret;
918
919 switch (mode) {
920 case NILFS_CHECKPOINT:
921 if (nilfs_checkpoint_is_mounted(cpfile->i_sb, cno))
922 /*
923 * Current implementation does not have to protect
924 * plain read-only mounts since they are exclusive
925 * with a read/write mount and are protected from the
926 * cleaner.
927 */
928 ret = -EBUSY;
929 else
930 ret = nilfs_cpfile_clear_snapshot(cpfile, cno);
931 return ret;
932 case NILFS_SNAPSHOT:
933 return nilfs_cpfile_set_snapshot(cpfile, cno);
934 default:
935 return -EINVAL;
936 }
937}
938
939/**
940 * nilfs_cpfile_get_stat - get checkpoint statistics
941 * @cpfile: inode of checkpoint file
942 * @stat: pointer to a structure of checkpoint statistics
943 *
944 * Description: nilfs_cpfile_get_stat() returns information about checkpoints.
945 *
946 * Return Value: On success, 0 is returned, and checkpoints information is
947 * stored in the place pointed by @stat. On error, one of the following
948 * negative error codes is returned.
949 *
950 * %-EIO - I/O error.
951 *
952 * %-ENOMEM - Insufficient amount of memory available.
953 */
954int nilfs_cpfile_get_stat(struct inode *cpfile, struct nilfs_cpstat *cpstat)
955{
956 struct buffer_head *bh;
957 struct nilfs_cpfile_header *header;
958 void *kaddr;
959 int ret;
960
961 down_read(&NILFS_MDT(cpfile)->mi_sem);
962
963 ret = nilfs_cpfile_get_header_block(cpfile, &bh);
964 if (ret < 0)
965 goto out_sem;
966 kaddr = kmap_atomic(bh->b_page);
967 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
968 cpstat->cs_cno = nilfs_mdt_cno(cpfile);
969 cpstat->cs_ncps = le64_to_cpu(header->ch_ncheckpoints);
970 cpstat->cs_nsss = le64_to_cpu(header->ch_nsnapshots);
971 kunmap_atomic(kaddr);
972 brelse(bh);
973
974 out_sem:
975 up_read(&NILFS_MDT(cpfile)->mi_sem);
976 return ret;
977}
978
979/**
980 * nilfs_cpfile_read - read or get cpfile inode
981 * @sb: super block instance
982 * @cpsize: size of a checkpoint entry
983 * @raw_inode: on-disk cpfile inode
984 * @inodep: buffer to store the inode
985 */
986int nilfs_cpfile_read(struct super_block *sb, size_t cpsize,
987 struct nilfs_inode *raw_inode, struct inode **inodep)
988{
989 struct inode *cpfile;
990 int err;
991
992 if (cpsize > sb->s_blocksize) {
993 nilfs_msg(sb, KERN_ERR,
994 "too large checkpoint size: %zu bytes", cpsize);
995 return -EINVAL;
996 } else if (cpsize < NILFS_MIN_CHECKPOINT_SIZE) {
997 nilfs_msg(sb, KERN_ERR,
998 "too small checkpoint size: %zu bytes", cpsize);
999 return -EINVAL;
1000 }
1001
1002 cpfile = nilfs_iget_locked(sb, NULL, NILFS_CPFILE_INO);
1003 if (unlikely(!cpfile))
1004 return -ENOMEM;
1005 if (!(cpfile->i_state & I_NEW))
1006 goto out;
1007
1008 err = nilfs_mdt_init(cpfile, NILFS_MDT_GFP, 0);
1009 if (err)
1010 goto failed;
1011
1012 nilfs_mdt_set_entry_size(cpfile, cpsize,
1013 sizeof(struct nilfs_cpfile_header));
1014
1015 err = nilfs_read_inode_common(cpfile, raw_inode);
1016 if (err)
1017 goto failed;
1018
1019 unlock_new_inode(cpfile);
1020 out:
1021 *inodep = cpfile;
1022 return 0;
1023 failed:
1024 iget_failed(cpfile);
1025 return err;
1026}