2 * cpfile.c - NILFS checkpoint file.
4 * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
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.
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.
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
20 * Written by Koji Sato <koji@osrg.net>.
23 #include <linux/kernel.h>
25 #include <linux/string.h>
26 #include <linux/buffer_head.h>
27 #include <linux/errno.h>
28 #include <linux/nilfs2_fs.h>
33 static inline unsigned long
34 nilfs_cpfile_checkpoints_per_block(const struct inode *cpfile)
36 return NILFS_MDT(cpfile)->mi_entries_per_block;
39 /* block number from the beginning of the file */
41 nilfs_cpfile_get_blkoff(const struct inode *cpfile, __u64 cno)
45 BUG_ON(cno == 0); /* checkpoint number 0 is invalid */
46 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
47 do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile));
48 return (unsigned long)tcno;
53 nilfs_cpfile_get_offset(const struct inode *cpfile, __u64 cno)
55 __u64 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
56 return do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile));
60 nilfs_cpfile_checkpoints_in_block(const struct inode *cpfile,
65 nilfs_cpfile_checkpoints_per_block(cpfile) -
66 nilfs_cpfile_get_offset(cpfile, curr),
70 static inline int nilfs_cpfile_is_in_first(const struct inode *cpfile,
73 return nilfs_cpfile_get_blkoff(cpfile, cno) == 0;
77 nilfs_cpfile_block_add_valid_checkpoints(const struct inode *cpfile,
78 struct buffer_head *bh,
82 struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
85 count = le32_to_cpu(cp->cp_checkpoints_count) + n;
86 cp->cp_checkpoints_count = cpu_to_le32(count);
91 nilfs_cpfile_block_sub_valid_checkpoints(const struct inode *cpfile,
92 struct buffer_head *bh,
96 struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
99 BUG_ON(le32_to_cpu(cp->cp_checkpoints_count) < n);
100 count = le32_to_cpu(cp->cp_checkpoints_count) - n;
101 cp->cp_checkpoints_count = cpu_to_le32(count);
105 static inline struct nilfs_cpfile_header *
106 nilfs_cpfile_block_get_header(const struct inode *cpfile,
107 struct buffer_head *bh,
110 return kaddr + bh_offset(bh);
113 static struct nilfs_checkpoint *
114 nilfs_cpfile_block_get_checkpoint(const struct inode *cpfile, __u64 cno,
115 struct buffer_head *bh,
118 return kaddr + bh_offset(bh) + nilfs_cpfile_get_offset(cpfile, cno) *
119 NILFS_MDT(cpfile)->mi_entry_size;
122 static void nilfs_cpfile_block_init(struct inode *cpfile,
123 struct buffer_head *bh,
126 struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
127 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
128 int n = nilfs_cpfile_checkpoints_per_block(cpfile);
131 nilfs_checkpoint_set_invalid(cp);
132 cp = (void *)cp + cpsz;
136 static inline int nilfs_cpfile_get_header_block(struct inode *cpfile,
137 struct buffer_head **bhp)
139 return nilfs_mdt_get_block(cpfile, 0, 0, NULL, bhp);
142 static inline int nilfs_cpfile_get_checkpoint_block(struct inode *cpfile,
145 struct buffer_head **bhp)
147 return nilfs_mdt_get_block(cpfile,
148 nilfs_cpfile_get_blkoff(cpfile, cno),
149 create, nilfs_cpfile_block_init, bhp);
152 static inline int nilfs_cpfile_delete_checkpoint_block(struct inode *cpfile,
155 return nilfs_mdt_delete_block(cpfile,
156 nilfs_cpfile_get_blkoff(cpfile, cno));
160 * nilfs_cpfile_get_checkpoint - get a checkpoint
161 * @cpfile: inode of checkpoint file
162 * @cno: checkpoint number
163 * @create: create flag
164 * @cpp: pointer to a checkpoint
165 * @bhp: pointer to a buffer head
167 * Description: nilfs_cpfile_get_checkpoint() acquires the checkpoint
168 * specified by @cno. A new checkpoint will be created if @cno is the current
169 * checkpoint number and @create is nonzero.
171 * Return Value: On success, 0 is returned, and the checkpoint and the
172 * buffer head of the buffer on which the checkpoint is located are stored in
173 * the place pointed by @cpp and @bhp, respectively. On error, one of the
174 * following negative error codes is returned.
178 * %-ENOMEM - Insufficient amount of memory available.
180 * %-ENOENT - No such checkpoint.
182 int nilfs_cpfile_get_checkpoint(struct inode *cpfile,
185 struct nilfs_checkpoint **cpp,
186 struct buffer_head **bhp)
188 struct buffer_head *header_bh, *cp_bh;
189 struct nilfs_cpfile_header *header;
190 struct nilfs_checkpoint *cp;
194 BUG_ON(cno < 1 || cno > nilfs_mdt_cno(cpfile) ||
195 (cno < nilfs_mdt_cno(cpfile) && create));
197 down_write(&NILFS_MDT(cpfile)->mi_sem);
199 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
202 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, create, &cp_bh);
205 kaddr = kmap(cp_bh->b_page);
206 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
207 if (nilfs_checkpoint_invalid(cp)) {
209 kunmap(cp_bh->b_page);
214 /* a newly-created checkpoint */
215 nilfs_checkpoint_clear_invalid(cp);
216 if (!nilfs_cpfile_is_in_first(cpfile, cno))
217 nilfs_cpfile_block_add_valid_checkpoints(cpfile, cp_bh,
219 nilfs_mdt_mark_buffer_dirty(cp_bh);
221 kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
222 header = nilfs_cpfile_block_get_header(cpfile, header_bh,
224 le64_add_cpu(&header->ch_ncheckpoints, 1);
225 kunmap_atomic(kaddr, KM_USER0);
226 nilfs_mdt_mark_buffer_dirty(header_bh);
227 nilfs_mdt_mark_dirty(cpfile);
238 up_write(&NILFS_MDT(cpfile)->mi_sem);
243 * nilfs_cpfile_put_checkpoint - put a checkpoint
244 * @cpfile: inode of checkpoint file
245 * @cno: checkpoint number
248 * Description: nilfs_cpfile_put_checkpoint() releases the checkpoint
249 * specified by @cno. @bh must be the buffer head which has been returned by
250 * a previous call to nilfs_cpfile_get_checkpoint() with @cno.
252 void nilfs_cpfile_put_checkpoint(struct inode *cpfile, __u64 cno,
253 struct buffer_head *bh)
260 * nilfs_cpfile_delete_checkpoints - delete checkpoints
261 * @cpfile: inode of checkpoint file
262 * @start: start checkpoint number
263 * @end: end checkpoint numer
265 * Description: nilfs_cpfile_delete_checkpoints() deletes the checkpoints in
266 * the period from @start to @end, excluding @end itself. The checkpoints
267 * which have been already deleted are ignored.
269 * Return Value: On success, 0 is returned. On error, one of the following
270 * negative error codes is returned.
274 * %-ENOMEM - Insufficient amount of memory available.
276 * %-EINVAL - invalid checkpoints.
278 int nilfs_cpfile_delete_checkpoints(struct inode *cpfile,
282 struct buffer_head *header_bh, *cp_bh;
283 struct nilfs_cpfile_header *header;
284 struct nilfs_checkpoint *cp;
285 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
288 unsigned long tnicps;
289 int ret, ncps, nicps, count, i;
291 if ((start == 0) || (start > end)) {
292 printk(KERN_CRIT "%s: start = %llu, end = %llu\n",
294 (unsigned long long)start,
295 (unsigned long long)end);
299 /* cannot delete the latest checkpoint */
300 if (start == nilfs_mdt_cno(cpfile) - 1)
303 down_write(&NILFS_MDT(cpfile)->mi_sem);
305 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
310 for (cno = start; cno < end; cno += ncps) {
311 ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, end);
312 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
321 kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
322 cp = nilfs_cpfile_block_get_checkpoint(
323 cpfile, cno, cp_bh, kaddr);
325 for (i = 0; i < ncps; i++, cp = (void *)cp + cpsz) {
326 BUG_ON(nilfs_checkpoint_snapshot(cp));
327 if (!nilfs_checkpoint_invalid(cp)) {
328 nilfs_checkpoint_set_invalid(cp);
334 nilfs_mdt_mark_buffer_dirty(cp_bh);
335 nilfs_mdt_mark_dirty(cpfile);
336 if (!nilfs_cpfile_is_in_first(cpfile, cno) &&
337 (count = nilfs_cpfile_block_sub_valid_checkpoints(
338 cpfile, cp_bh, kaddr, nicps)) == 0) {
340 kunmap_atomic(kaddr, KM_USER0);
342 ret = nilfs_cpfile_delete_checkpoint_block(
346 printk(KERN_ERR "%s: cannot delete block\n",
352 kunmap_atomic(kaddr, KM_USER0);
357 kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
358 header = nilfs_cpfile_block_get_header(cpfile, header_bh,
360 le64_add_cpu(&header->ch_ncheckpoints, -tnicps);
361 nilfs_mdt_mark_buffer_dirty(header_bh);
362 nilfs_mdt_mark_dirty(cpfile);
363 kunmap_atomic(kaddr, KM_USER0);
368 up_write(&NILFS_MDT(cpfile)->mi_sem);
372 static void nilfs_cpfile_checkpoint_to_cpinfo(struct inode *cpfile,
373 struct nilfs_checkpoint *cp,
374 struct nilfs_cpinfo *ci)
376 ci->ci_flags = le32_to_cpu(cp->cp_flags);
377 ci->ci_cno = le64_to_cpu(cp->cp_cno);
378 ci->ci_create = le64_to_cpu(cp->cp_create);
379 ci->ci_nblk_inc = le64_to_cpu(cp->cp_nblk_inc);
380 ci->ci_inodes_count = le64_to_cpu(cp->cp_inodes_count);
381 ci->ci_blocks_count = le64_to_cpu(cp->cp_blocks_count);
382 ci->ci_next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
385 static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 cno,
386 struct nilfs_cpinfo *ci, size_t nci)
388 struct nilfs_checkpoint *cp;
389 struct buffer_head *bh;
390 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
391 __u64 cur_cno = nilfs_mdt_cno(cpfile);
396 down_read(&NILFS_MDT(cpfile)->mi_sem);
398 for (n = 0; cno < cur_cno && n < nci; cno += ncps) {
399 ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, cur_cno);
400 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
404 continue; /* skip hole */
407 kaddr = kmap_atomic(bh->b_page, KM_USER0);
408 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
409 for (i = 0; i < ncps && n < nci; i++, cp = (void *)cp + cpsz) {
410 if (!nilfs_checkpoint_invalid(cp))
411 nilfs_cpfile_checkpoint_to_cpinfo(
412 cpfile, cp, &ci[n++]);
414 kunmap_atomic(kaddr, KM_USER0);
421 up_read(&NILFS_MDT(cpfile)->mi_sem);
425 static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 cno,
426 struct nilfs_cpinfo *ci, size_t nci)
428 struct buffer_head *bh;
429 struct nilfs_cpfile_header *header;
430 struct nilfs_checkpoint *cp;
432 unsigned long curr_blkoff, next_blkoff;
436 down_read(&NILFS_MDT(cpfile)->mi_sem);
439 ret = nilfs_cpfile_get_header_block(cpfile, &bh);
442 kaddr = kmap_atomic(bh->b_page, KM_USER0);
443 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
444 curr = le64_to_cpu(header->ch_snapshot_list.ssl_next);
445 kunmap_atomic(kaddr, KM_USER0);
453 curr_blkoff = nilfs_cpfile_get_blkoff(cpfile, curr);
454 ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr, 0, &bh);
457 kaddr = kmap_atomic(bh->b_page, KM_USER0);
458 for (n = 0; n < nci; n++) {
459 cp = nilfs_cpfile_block_get_checkpoint(
460 cpfile, curr, bh, kaddr);
461 nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, &ci[n]);
462 next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
468 next_blkoff = nilfs_cpfile_get_blkoff(cpfile, next);
469 if (curr_blkoff != next_blkoff) {
470 kunmap_atomic(kaddr, KM_USER0);
472 ret = nilfs_cpfile_get_checkpoint_block(cpfile, next,
476 kaddr = kmap_atomic(bh->b_page, KM_USER0);
479 curr_blkoff = next_blkoff;
481 kunmap_atomic(kaddr, KM_USER0);
486 up_read(&NILFS_MDT(cpfile)->mi_sem);
491 * nilfs_cpfile_get_cpinfo -
497 ssize_t nilfs_cpfile_get_cpinfo(struct inode *cpfile,
499 struct nilfs_cpinfo *ci, size_t nci)
502 case NILFS_CHECKPOINT:
503 return nilfs_cpfile_do_get_cpinfo(cpfile, cno, ci, nci);
505 return nilfs_cpfile_do_get_ssinfo(cpfile, cno, ci, nci);
512 * nilfs_cpfile_delete_checkpoint -
516 int nilfs_cpfile_delete_checkpoint(struct inode *cpfile, __u64 cno)
518 struct nilfs_cpinfo ci;
522 /* checkpoint number 0 is invalid */
525 nci = nilfs_cpfile_do_get_cpinfo(cpfile, cno, &ci, 1);
528 else if (nci == 0 || ci.ci_cno != cno)
531 /* cannot delete the latest checkpoint nor snapshots */
532 ret = nilfs_cpinfo_snapshot(&ci);
535 else if (ret > 0 || cno == nilfs_mdt_cno(cpfile) - 1)
538 return nilfs_cpfile_delete_checkpoints(cpfile, cno, cno + 1);
541 static struct nilfs_snapshot_list *
542 nilfs_cpfile_block_get_snapshot_list(const struct inode *cpfile,
544 struct buffer_head *bh,
547 struct nilfs_cpfile_header *header;
548 struct nilfs_checkpoint *cp;
549 struct nilfs_snapshot_list *list;
552 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
553 list = &cp->cp_snapshot_list;
555 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
556 list = &header->ch_snapshot_list;
561 static int nilfs_cpfile_set_snapshot(struct inode *cpfile, __u64 cno)
563 struct buffer_head *header_bh, *curr_bh, *prev_bh, *cp_bh;
564 struct nilfs_cpfile_header *header;
565 struct nilfs_checkpoint *cp;
566 struct nilfs_snapshot_list *list;
568 unsigned long curr_blkoff, prev_blkoff;
572 down_write(&NILFS_MDT(cpfile)->mi_sem);
574 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
577 kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
578 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
579 if (nilfs_checkpoint_invalid(cp)) {
581 kunmap_atomic(kaddr, KM_USER0);
584 if (nilfs_checkpoint_snapshot(cp)) {
586 kunmap_atomic(kaddr, KM_USER0);
589 kunmap_atomic(kaddr, KM_USER0);
591 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
594 kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
595 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
596 list = &header->ch_snapshot_list;
601 prev = le64_to_cpu(list->ssl_prev);
603 prev_blkoff = nilfs_cpfile_get_blkoff(cpfile, prev);
605 if (curr_blkoff != prev_blkoff) {
606 kunmap_atomic(kaddr, KM_USER0);
608 ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr,
612 kaddr = kmap_atomic(curr_bh->b_page, KM_USER0);
614 curr_blkoff = prev_blkoff;
615 cp = nilfs_cpfile_block_get_checkpoint(
616 cpfile, curr, curr_bh, kaddr);
617 list = &cp->cp_snapshot_list;
618 prev = le64_to_cpu(list->ssl_prev);
620 kunmap_atomic(kaddr, KM_USER0);
623 ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
632 kaddr = kmap_atomic(curr_bh->b_page, KM_USER0);
633 list = nilfs_cpfile_block_get_snapshot_list(
634 cpfile, curr, curr_bh, kaddr);
635 list->ssl_prev = cpu_to_le64(cno);
636 kunmap_atomic(kaddr, KM_USER0);
638 kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
639 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
640 cp->cp_snapshot_list.ssl_next = cpu_to_le64(curr);
641 cp->cp_snapshot_list.ssl_prev = cpu_to_le64(prev);
642 nilfs_checkpoint_set_snapshot(cp);
643 kunmap_atomic(kaddr, KM_USER0);
645 kaddr = kmap_atomic(prev_bh->b_page, KM_USER0);
646 list = nilfs_cpfile_block_get_snapshot_list(
647 cpfile, prev, prev_bh, kaddr);
648 list->ssl_next = cpu_to_le64(cno);
649 kunmap_atomic(kaddr, KM_USER0);
651 kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
652 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
653 le64_add_cpu(&header->ch_nsnapshots, 1);
654 kunmap_atomic(kaddr, KM_USER0);
656 nilfs_mdt_mark_buffer_dirty(prev_bh);
657 nilfs_mdt_mark_buffer_dirty(curr_bh);
658 nilfs_mdt_mark_buffer_dirty(cp_bh);
659 nilfs_mdt_mark_buffer_dirty(header_bh);
660 nilfs_mdt_mark_dirty(cpfile);
674 up_write(&NILFS_MDT(cpfile)->mi_sem);
678 static int nilfs_cpfile_clear_snapshot(struct inode *cpfile, __u64 cno)
680 struct buffer_head *header_bh, *next_bh, *prev_bh, *cp_bh;
681 struct nilfs_cpfile_header *header;
682 struct nilfs_checkpoint *cp;
683 struct nilfs_snapshot_list *list;
688 down_write(&NILFS_MDT(cpfile)->mi_sem);
690 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
693 kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
694 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
695 if (nilfs_checkpoint_invalid(cp)) {
697 kunmap_atomic(kaddr, KM_USER0);
700 if (!nilfs_checkpoint_snapshot(cp)) {
702 kunmap_atomic(kaddr, KM_USER0);
706 list = &cp->cp_snapshot_list;
707 next = le64_to_cpu(list->ssl_next);
708 prev = le64_to_cpu(list->ssl_prev);
709 kunmap_atomic(kaddr, KM_USER0);
711 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
715 ret = nilfs_cpfile_get_checkpoint_block(cpfile, next, 0,
724 ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
733 kaddr = kmap_atomic(next_bh->b_page, KM_USER0);
734 list = nilfs_cpfile_block_get_snapshot_list(
735 cpfile, next, next_bh, kaddr);
736 list->ssl_prev = cpu_to_le64(prev);
737 kunmap_atomic(kaddr, KM_USER0);
739 kaddr = kmap_atomic(prev_bh->b_page, KM_USER0);
740 list = nilfs_cpfile_block_get_snapshot_list(
741 cpfile, prev, prev_bh, kaddr);
742 list->ssl_next = cpu_to_le64(next);
743 kunmap_atomic(kaddr, KM_USER0);
745 kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
746 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
747 cp->cp_snapshot_list.ssl_next = cpu_to_le64(0);
748 cp->cp_snapshot_list.ssl_prev = cpu_to_le64(0);
749 nilfs_checkpoint_clear_snapshot(cp);
750 kunmap_atomic(kaddr, KM_USER0);
752 kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
753 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
754 le64_add_cpu(&header->ch_nsnapshots, -1);
755 kunmap_atomic(kaddr, KM_USER0);
757 nilfs_mdt_mark_buffer_dirty(next_bh);
758 nilfs_mdt_mark_buffer_dirty(prev_bh);
759 nilfs_mdt_mark_buffer_dirty(cp_bh);
760 nilfs_mdt_mark_buffer_dirty(header_bh);
761 nilfs_mdt_mark_dirty(cpfile);
775 up_write(&NILFS_MDT(cpfile)->mi_sem);
780 * nilfs_cpfile_is_snapshot -
781 * @cpfile: inode of checkpoint file
782 * @cno: checkpoint number
786 * Return Value: On success, 1 is returned if the checkpoint specified by
787 * @cno is a snapshot, or 0 if not. On error, one of the following negative
788 * error codes is returned.
792 * %-ENOMEM - Insufficient amount of memory available.
794 * %-ENOENT - No such checkpoint.
796 int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
798 struct buffer_head *bh;
799 struct nilfs_checkpoint *cp;
803 down_read(&NILFS_MDT(cpfile)->mi_sem);
805 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
808 kaddr = kmap_atomic(bh->b_page, KM_USER0);
809 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
810 ret = nilfs_checkpoint_snapshot(cp);
811 kunmap_atomic(kaddr, KM_USER0);
815 up_read(&NILFS_MDT(cpfile)->mi_sem);
820 * nilfs_cpfile_change_cpmode - change checkpoint mode
821 * @cpfile: inode of checkpoint file
822 * @cno: checkpoint number
823 * @status: mode of checkpoint
825 * Description: nilfs_change_cpmode() changes the mode of the checkpoint
826 * specified by @cno. The mode @mode is NILFS_CHECKPOINT or NILFS_SNAPSHOT.
828 * Return Value: On success, 0 is returned. On error, one of the following
829 * negative error codes is returned.
833 * %-ENOMEM - Insufficient amount of memory available.
835 * %-ENOENT - No such checkpoint.
837 int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode)
839 struct the_nilfs *nilfs;
842 nilfs = NILFS_MDT(cpfile)->mi_nilfs;
845 case NILFS_CHECKPOINT:
847 * Check for protecting existing snapshot mounts:
848 * bd_mount_sem is used to make this operation atomic and
849 * exclusive with a new mount job. Though it doesn't cover
850 * umount, it's enough for the purpose.
852 down(&nilfs->ns_bdev->bd_mount_sem);
853 if (nilfs_checkpoint_is_mounted(nilfs, cno, 1)) {
854 /* Current implementation does not have to protect
855 plain read-only mounts since they are exclusive
856 with a read/write mount and are protected from the
860 ret = nilfs_cpfile_clear_snapshot(cpfile, cno);
861 up(&nilfs->ns_bdev->bd_mount_sem);
864 return nilfs_cpfile_set_snapshot(cpfile, cno);
871 * nilfs_cpfile_get_stat - get checkpoint statistics
872 * @cpfile: inode of checkpoint file
873 * @stat: pointer to a structure of checkpoint statistics
875 * Description: nilfs_cpfile_get_stat() returns information about checkpoints.
877 * Return Value: On success, 0 is returned, and checkpoints information is
878 * stored in the place pointed by @stat. On error, one of the following
879 * negative error codes is returned.
883 * %-ENOMEM - Insufficient amount of memory available.
885 int nilfs_cpfile_get_stat(struct inode *cpfile, struct nilfs_cpstat *cpstat)
887 struct buffer_head *bh;
888 struct nilfs_cpfile_header *header;
892 down_read(&NILFS_MDT(cpfile)->mi_sem);
894 ret = nilfs_cpfile_get_header_block(cpfile, &bh);
897 kaddr = kmap_atomic(bh->b_page, KM_USER0);
898 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
899 cpstat->cs_cno = nilfs_mdt_cno(cpfile);
900 cpstat->cs_ncps = le64_to_cpu(header->ch_ncheckpoints);
901 cpstat->cs_nsss = le64_to_cpu(header->ch_nsnapshots);
902 kunmap_atomic(kaddr, KM_USER0);
906 up_read(&NILFS_MDT(cpfile)->mi_sem);