blob: e90b60dfced9c40f728546400940f6ff12afb5a9 [file] [log] [blame]
Koji Sato29619802009-04-06 19:01:31 -07001/*
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{
Ryusuke Konishi1f5abe72009-04-06 19:01:55 -070043 __u64 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
Koji Sato29619802009-04-06 19:01:31 -070044 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 unsigned long
57nilfs_cpfile_checkpoints_in_block(const struct inode *cpfile,
58 __u64 curr,
59 __u64 max)
60{
61 return min_t(__u64,
62 nilfs_cpfile_checkpoints_per_block(cpfile) -
63 nilfs_cpfile_get_offset(cpfile, curr),
64 max - curr);
65}
66
67static inline int nilfs_cpfile_is_in_first(const struct inode *cpfile,
68 __u64 cno)
69{
70 return nilfs_cpfile_get_blkoff(cpfile, cno) == 0;
71}
72
73static unsigned int
74nilfs_cpfile_block_add_valid_checkpoints(const struct inode *cpfile,
75 struct buffer_head *bh,
76 void *kaddr,
77 unsigned int n)
78{
79 struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
80 unsigned int count;
81
82 count = le32_to_cpu(cp->cp_checkpoints_count) + n;
83 cp->cp_checkpoints_count = cpu_to_le32(count);
84 return count;
85}
86
87static unsigned int
88nilfs_cpfile_block_sub_valid_checkpoints(const struct inode *cpfile,
89 struct buffer_head *bh,
90 void *kaddr,
91 unsigned int n)
92{
93 struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
94 unsigned int count;
95
Ryusuke Konishi1f5abe72009-04-06 19:01:55 -070096 WARN_ON(le32_to_cpu(cp->cp_checkpoints_count) < n);
Koji Sato29619802009-04-06 19:01:31 -070097 count = le32_to_cpu(cp->cp_checkpoints_count) - n;
98 cp->cp_checkpoints_count = cpu_to_le32(count);
99 return count;
100}
101
102static inline struct nilfs_cpfile_header *
103nilfs_cpfile_block_get_header(const struct inode *cpfile,
104 struct buffer_head *bh,
105 void *kaddr)
106{
107 return kaddr + bh_offset(bh);
108}
109
110static struct nilfs_checkpoint *
111nilfs_cpfile_block_get_checkpoint(const struct inode *cpfile, __u64 cno,
112 struct buffer_head *bh,
113 void *kaddr)
114{
115 return kaddr + bh_offset(bh) + nilfs_cpfile_get_offset(cpfile, cno) *
116 NILFS_MDT(cpfile)->mi_entry_size;
117}
118
119static void nilfs_cpfile_block_init(struct inode *cpfile,
120 struct buffer_head *bh,
121 void *kaddr)
122{
123 struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
124 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
125 int n = nilfs_cpfile_checkpoints_per_block(cpfile);
126
127 while (n-- > 0) {
128 nilfs_checkpoint_set_invalid(cp);
129 cp = (void *)cp + cpsz;
130 }
131}
132
133static inline int nilfs_cpfile_get_header_block(struct inode *cpfile,
134 struct buffer_head **bhp)
135{
136 return nilfs_mdt_get_block(cpfile, 0, 0, NULL, bhp);
137}
138
139static inline int nilfs_cpfile_get_checkpoint_block(struct inode *cpfile,
140 __u64 cno,
141 int create,
142 struct buffer_head **bhp)
143{
144 return nilfs_mdt_get_block(cpfile,
145 nilfs_cpfile_get_blkoff(cpfile, cno),
146 create, nilfs_cpfile_block_init, bhp);
147}
148
149static inline int nilfs_cpfile_delete_checkpoint_block(struct inode *cpfile,
150 __u64 cno)
151{
152 return nilfs_mdt_delete_block(cpfile,
153 nilfs_cpfile_get_blkoff(cpfile, cno));
154}
155
156/**
157 * nilfs_cpfile_get_checkpoint - get a checkpoint
158 * @cpfile: inode of checkpoint file
159 * @cno: checkpoint number
160 * @create: create flag
161 * @cpp: pointer to a checkpoint
162 * @bhp: pointer to a buffer head
163 *
164 * Description: nilfs_cpfile_get_checkpoint() acquires the checkpoint
165 * specified by @cno. A new checkpoint will be created if @cno is the current
166 * checkpoint number and @create is nonzero.
167 *
168 * Return Value: On success, 0 is returned, and the checkpoint and the
169 * buffer head of the buffer on which the checkpoint is located are stored in
170 * the place pointed by @cpp and @bhp, respectively. On error, one of the
171 * following negative error codes is returned.
172 *
173 * %-EIO - I/O error.
174 *
175 * %-ENOMEM - Insufficient amount of memory available.
176 *
177 * %-ENOENT - No such checkpoint.
Ryusuke Konishi1f5abe72009-04-06 19:01:55 -0700178 *
179 * %-EINVAL - invalid checkpoint.
Koji Sato29619802009-04-06 19:01:31 -0700180 */
181int nilfs_cpfile_get_checkpoint(struct inode *cpfile,
182 __u64 cno,
183 int create,
184 struct nilfs_checkpoint **cpp,
185 struct buffer_head **bhp)
186{
187 struct buffer_head *header_bh, *cp_bh;
188 struct nilfs_cpfile_header *header;
189 struct nilfs_checkpoint *cp;
190 void *kaddr;
191 int ret;
192
Ryusuke Konishi1f5abe72009-04-06 19:01:55 -0700193 if (unlikely(cno < 1 || cno > nilfs_mdt_cno(cpfile) ||
194 (cno < nilfs_mdt_cno(cpfile) && create)))
195 return -EINVAL;
Koji Sato29619802009-04-06 19:01:31 -0700196
197 down_write(&NILFS_MDT(cpfile)->mi_sem);
198
199 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
200 if (ret < 0)
201 goto out_sem;
202 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, create, &cp_bh);
203 if (ret < 0)
204 goto out_header;
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)) {
208 if (!create) {
209 kunmap(cp_bh->b_page);
210 brelse(cp_bh);
211 ret = -ENOENT;
212 goto out_header;
213 }
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,
218 kaddr, 1);
219 nilfs_mdt_mark_buffer_dirty(cp_bh);
220
221 kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
222 header = nilfs_cpfile_block_get_header(cpfile, header_bh,
223 kaddr);
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);
228 }
229
230 if (cpp != NULL)
231 *cpp = cp;
232 *bhp = cp_bh;
233
234 out_header:
235 brelse(header_bh);
236
237 out_sem:
238 up_write(&NILFS_MDT(cpfile)->mi_sem);
239 return ret;
240}
241
242/**
243 * nilfs_cpfile_put_checkpoint - put a checkpoint
244 * @cpfile: inode of checkpoint file
245 * @cno: checkpoint number
246 * @bh: buffer head
247 *
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.
251 */
252void nilfs_cpfile_put_checkpoint(struct inode *cpfile, __u64 cno,
253 struct buffer_head *bh)
254{
255 kunmap(bh->b_page);
256 brelse(bh);
257}
258
259/**
260 * nilfs_cpfile_delete_checkpoints - delete checkpoints
261 * @cpfile: inode of checkpoint file
262 * @start: start checkpoint number
263 * @end: end checkpoint numer
264 *
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.
268 *
269 * Return Value: On success, 0 is returned. On error, one of the following
270 * negative error codes is returned.
271 *
272 * %-EIO - I/O error.
273 *
274 * %-ENOMEM - Insufficient amount of memory available.
275 *
276 * %-EINVAL - invalid checkpoints.
277 */
278int nilfs_cpfile_delete_checkpoints(struct inode *cpfile,
279 __u64 start,
280 __u64 end)
281{
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;
286 __u64 cno;
287 void *kaddr;
288 unsigned long tnicps;
289 int ret, ncps, nicps, count, i;
290
Ryusuke Konishi1f5abe72009-04-06 19:01:55 -0700291 if (unlikely(start == 0 || start > end)) {
292 printk(KERN_ERR "%s: invalid range of checkpoint numbers: "
293 "[%llu, %llu)\n", __func__,
294 (unsigned long long)start, (unsigned long long)end);
295 return -EINVAL;
Koji Sato29619802009-04-06 19:01:31 -0700296 }
297
298 /* cannot delete the latest checkpoint */
299 if (start == nilfs_mdt_cno(cpfile) - 1)
300 return -EPERM;
301
302 down_write(&NILFS_MDT(cpfile)->mi_sem);
303
304 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
305 if (ret < 0)
306 goto out_sem;
307 tnicps = 0;
308
309 for (cno = start; cno < end; cno += ncps) {
310 ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, end);
311 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
312 if (ret < 0) {
313 if (ret != -ENOENT)
314 goto out_sem;
315 /* skip hole */
316 ret = 0;
317 continue;
318 }
319
320 kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
321 cp = nilfs_cpfile_block_get_checkpoint(
322 cpfile, cno, cp_bh, kaddr);
323 nicps = 0;
324 for (i = 0; i < ncps; i++, cp = (void *)cp + cpsz) {
Ryusuke Konishi1f5abe72009-04-06 19:01:55 -0700325 WARN_ON(nilfs_checkpoint_snapshot(cp));
Koji Sato29619802009-04-06 19:01:31 -0700326 if (!nilfs_checkpoint_invalid(cp)) {
327 nilfs_checkpoint_set_invalid(cp);
328 nicps++;
329 }
330 }
331 if (nicps > 0) {
332 tnicps += nicps;
333 nilfs_mdt_mark_buffer_dirty(cp_bh);
334 nilfs_mdt_mark_dirty(cpfile);
335 if (!nilfs_cpfile_is_in_first(cpfile, cno) &&
336 (count = nilfs_cpfile_block_sub_valid_checkpoints(
337 cpfile, cp_bh, kaddr, nicps)) == 0) {
338 /* make hole */
339 kunmap_atomic(kaddr, KM_USER0);
340 brelse(cp_bh);
341 ret = nilfs_cpfile_delete_checkpoint_block(
342 cpfile, cno);
343 if (ret == 0)
344 continue;
345 printk(KERN_ERR "%s: cannot delete block\n",
346 __func__);
347 goto out_sem;
348 }
349 }
350
351 kunmap_atomic(kaddr, KM_USER0);
352 brelse(cp_bh);
353 }
354
355 if (tnicps > 0) {
356 kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
357 header = nilfs_cpfile_block_get_header(cpfile, header_bh,
358 kaddr);
Koji Sato6c98cd42009-04-06 19:01:32 -0700359 le64_add_cpu(&header->ch_ncheckpoints, -(u64)tnicps);
Koji Sato29619802009-04-06 19:01:31 -0700360 nilfs_mdt_mark_buffer_dirty(header_bh);
361 nilfs_mdt_mark_dirty(cpfile);
362 kunmap_atomic(kaddr, KM_USER0);
363 }
364 brelse(header_bh);
365
366 out_sem:
367 up_write(&NILFS_MDT(cpfile)->mi_sem);
368 return ret;
369}
370
371static void nilfs_cpfile_checkpoint_to_cpinfo(struct inode *cpfile,
372 struct nilfs_checkpoint *cp,
373 struct nilfs_cpinfo *ci)
374{
375 ci->ci_flags = le32_to_cpu(cp->cp_flags);
376 ci->ci_cno = le64_to_cpu(cp->cp_cno);
377 ci->ci_create = le64_to_cpu(cp->cp_create);
378 ci->ci_nblk_inc = le64_to_cpu(cp->cp_nblk_inc);
379 ci->ci_inodes_count = le64_to_cpu(cp->cp_inodes_count);
380 ci->ci_blocks_count = le64_to_cpu(cp->cp_blocks_count);
381 ci->ci_next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
382}
383
Ryusuke Konishi76068c42009-04-06 19:01:50 -0700384static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop,
Koji Sato29619802009-04-06 19:01:31 -0700385 struct nilfs_cpinfo *ci, size_t nci)
386{
387 struct nilfs_checkpoint *cp;
388 struct buffer_head *bh;
389 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
Ryusuke Konishi76068c42009-04-06 19:01:50 -0700390 __u64 cur_cno = nilfs_mdt_cno(cpfile), cno = *cnop;
Koji Sato29619802009-04-06 19:01:31 -0700391 void *kaddr;
392 int n, ret;
393 int ncps, i;
394
Ryusuke Konishi1f5abe72009-04-06 19:01:55 -0700395 if (cno == 0)
396 return -ENOENT; /* checkpoint number 0 is invalid */
Koji Sato29619802009-04-06 19:01:31 -0700397 down_read(&NILFS_MDT(cpfile)->mi_sem);
398
399 for (n = 0; cno < cur_cno && n < nci; cno += ncps) {
400 ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, cur_cno);
401 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
402 if (ret < 0) {
403 if (ret != -ENOENT)
404 goto out;
405 continue; /* skip hole */
406 }
407
408 kaddr = kmap_atomic(bh->b_page, KM_USER0);
409 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
410 for (i = 0; i < ncps && n < nci; i++, cp = (void *)cp + cpsz) {
411 if (!nilfs_checkpoint_invalid(cp))
412 nilfs_cpfile_checkpoint_to_cpinfo(
413 cpfile, cp, &ci[n++]);
414 }
415 kunmap_atomic(kaddr, KM_USER0);
416 brelse(bh);
417 }
418
419 ret = n;
Ryusuke Konishi76068c42009-04-06 19:01:50 -0700420 if (n > 0)
421 *cnop = ci[n - 1].ci_cno + 1;
Koji Sato29619802009-04-06 19:01:31 -0700422
423 out:
424 up_read(&NILFS_MDT(cpfile)->mi_sem);
425 return ret;
426}
427
Ryusuke Konishib028fcf2009-04-06 19:01:47 -0700428static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
Koji Sato29619802009-04-06 19:01:31 -0700429 struct nilfs_cpinfo *ci, size_t nci)
430{
431 struct buffer_head *bh;
432 struct nilfs_cpfile_header *header;
433 struct nilfs_checkpoint *cp;
Ryusuke Konishib028fcf2009-04-06 19:01:47 -0700434 __u64 curr = *cnop, next;
Koji Sato29619802009-04-06 19:01:31 -0700435 unsigned long curr_blkoff, next_blkoff;
436 void *kaddr;
Ryusuke Konishi7fa10d22009-04-06 19:01:48 -0700437 int n = 0, ret;
Koji Sato29619802009-04-06 19:01:31 -0700438
439 down_read(&NILFS_MDT(cpfile)->mi_sem);
440
Ryusuke Konishib028fcf2009-04-06 19:01:47 -0700441 if (curr == 0) {
Koji Sato29619802009-04-06 19:01:31 -0700442 ret = nilfs_cpfile_get_header_block(cpfile, &bh);
443 if (ret < 0)
444 goto out;
445 kaddr = kmap_atomic(bh->b_page, KM_USER0);
446 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
447 curr = le64_to_cpu(header->ch_snapshot_list.ssl_next);
448 kunmap_atomic(kaddr, KM_USER0);
449 brelse(bh);
450 if (curr == 0) {
451 ret = 0;
452 goto out;
453 }
Ryusuke Konishib028fcf2009-04-06 19:01:47 -0700454 } else if (unlikely(curr == ~(__u64)0)) {
455 ret = 0;
456 goto out;
457 }
458
Koji Sato29619802009-04-06 19:01:31 -0700459 curr_blkoff = nilfs_cpfile_get_blkoff(cpfile, curr);
460 ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr, 0, &bh);
Ryusuke Konishi7fa10d22009-04-06 19:01:48 -0700461 if (unlikely(ret < 0)) {
462 if (ret == -ENOENT)
463 ret = 0; /* No snapshots (started from a hole block) */
Koji Sato29619802009-04-06 19:01:31 -0700464 goto out;
Ryusuke Konishi7fa10d22009-04-06 19:01:48 -0700465 }
Koji Sato29619802009-04-06 19:01:31 -0700466 kaddr = kmap_atomic(bh->b_page, KM_USER0);
Ryusuke Konishi7fa10d22009-04-06 19:01:48 -0700467 while (n < nci) {
468 cp = nilfs_cpfile_block_get_checkpoint(cpfile, curr, bh, kaddr);
469 curr = ~(__u64)0; /* Terminator */
470 if (unlikely(nilfs_checkpoint_invalid(cp) ||
471 !nilfs_checkpoint_snapshot(cp)))
Koji Sato29619802009-04-06 19:01:31 -0700472 break;
Ryusuke Konishi7fa10d22009-04-06 19:01:48 -0700473 nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, &ci[n++]);
474 next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
475 if (next == 0)
476 break; /* reach end of the snapshot list */
477
Koji Sato29619802009-04-06 19:01:31 -0700478 next_blkoff = nilfs_cpfile_get_blkoff(cpfile, next);
479 if (curr_blkoff != next_blkoff) {
480 kunmap_atomic(kaddr, KM_USER0);
481 brelse(bh);
482 ret = nilfs_cpfile_get_checkpoint_block(cpfile, next,
483 0, &bh);
Ryusuke Konishi7fa10d22009-04-06 19:01:48 -0700484 if (unlikely(ret < 0)) {
485 WARN_ON(ret == -ENOENT);
Koji Sato29619802009-04-06 19:01:31 -0700486 goto out;
Ryusuke Konishi7fa10d22009-04-06 19:01:48 -0700487 }
Koji Sato29619802009-04-06 19:01:31 -0700488 kaddr = kmap_atomic(bh->b_page, KM_USER0);
489 }
490 curr = next;
491 curr_blkoff = next_blkoff;
492 }
493 kunmap_atomic(kaddr, KM_USER0);
494 brelse(bh);
Ryusuke Konishib028fcf2009-04-06 19:01:47 -0700495 *cnop = curr;
Koji Sato29619802009-04-06 19:01:31 -0700496 ret = n;
497
498 out:
499 up_read(&NILFS_MDT(cpfile)->mi_sem);
500 return ret;
501}
502
503/**
504 * nilfs_cpfile_get_cpinfo -
505 * @cpfile:
506 * @cno:
507 * @ci:
508 * @nci:
509 */
Ryusuke Konishib028fcf2009-04-06 19:01:47 -0700510
511ssize_t nilfs_cpfile_get_cpinfo(struct inode *cpfile, __u64 *cnop, int mode,
Koji Sato29619802009-04-06 19:01:31 -0700512 struct nilfs_cpinfo *ci, size_t nci)
513{
514 switch (mode) {
515 case NILFS_CHECKPOINT:
Ryusuke Konishi76068c42009-04-06 19:01:50 -0700516 return nilfs_cpfile_do_get_cpinfo(cpfile, cnop, ci, nci);
Koji Sato29619802009-04-06 19:01:31 -0700517 case NILFS_SNAPSHOT:
Ryusuke Konishib028fcf2009-04-06 19:01:47 -0700518 return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, ci, nci);
Koji Sato29619802009-04-06 19:01:31 -0700519 default:
520 return -EINVAL;
521 }
522}
523
524/**
525 * nilfs_cpfile_delete_checkpoint -
526 * @cpfile:
527 * @cno:
528 */
529int nilfs_cpfile_delete_checkpoint(struct inode *cpfile, __u64 cno)
530{
531 struct nilfs_cpinfo ci;
Ryusuke Konishi76068c42009-04-06 19:01:50 -0700532 __u64 tcno = cno;
Koji Sato29619802009-04-06 19:01:31 -0700533 ssize_t nci;
534 int ret;
535
Ryusuke Konishi76068c42009-04-06 19:01:50 -0700536 nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, 1);
Koji Sato29619802009-04-06 19:01:31 -0700537 if (nci < 0)
538 return nci;
539 else if (nci == 0 || ci.ci_cno != cno)
540 return -ENOENT;
541
542 /* cannot delete the latest checkpoint nor snapshots */
543 ret = nilfs_cpinfo_snapshot(&ci);
544 if (ret < 0)
545 return ret;
546 else if (ret > 0 || cno == nilfs_mdt_cno(cpfile) - 1)
547 return -EPERM;
548
549 return nilfs_cpfile_delete_checkpoints(cpfile, cno, cno + 1);
550}
551
552static struct nilfs_snapshot_list *
553nilfs_cpfile_block_get_snapshot_list(const struct inode *cpfile,
554 __u64 cno,
555 struct buffer_head *bh,
556 void *kaddr)
557{
558 struct nilfs_cpfile_header *header;
559 struct nilfs_checkpoint *cp;
560 struct nilfs_snapshot_list *list;
561
562 if (cno != 0) {
563 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
564 list = &cp->cp_snapshot_list;
565 } else {
566 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
567 list = &header->ch_snapshot_list;
568 }
569 return list;
570}
571
572static int nilfs_cpfile_set_snapshot(struct inode *cpfile, __u64 cno)
573{
574 struct buffer_head *header_bh, *curr_bh, *prev_bh, *cp_bh;
575 struct nilfs_cpfile_header *header;
576 struct nilfs_checkpoint *cp;
577 struct nilfs_snapshot_list *list;
578 __u64 curr, prev;
579 unsigned long curr_blkoff, prev_blkoff;
580 void *kaddr;
581 int ret;
582
Ryusuke Konishi1f5abe72009-04-06 19:01:55 -0700583 if (cno == 0)
584 return -ENOENT; /* checkpoint number 0 is invalid */
Koji Sato29619802009-04-06 19:01:31 -0700585 down_write(&NILFS_MDT(cpfile)->mi_sem);
586
587 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
588 if (ret < 0)
589 goto out_sem;
590 kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
591 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
592 if (nilfs_checkpoint_invalid(cp)) {
593 ret = -ENOENT;
594 kunmap_atomic(kaddr, KM_USER0);
595 goto out_cp;
596 }
597 if (nilfs_checkpoint_snapshot(cp)) {
598 ret = 0;
599 kunmap_atomic(kaddr, KM_USER0);
600 goto out_cp;
601 }
602 kunmap_atomic(kaddr, KM_USER0);
603
604 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
605 if (ret < 0)
606 goto out_cp;
607 kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
608 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
609 list = &header->ch_snapshot_list;
610 curr_bh = header_bh;
611 get_bh(curr_bh);
612 curr = 0;
613 curr_blkoff = 0;
614 prev = le64_to_cpu(list->ssl_prev);
615 while (prev > cno) {
616 prev_blkoff = nilfs_cpfile_get_blkoff(cpfile, prev);
617 curr = prev;
618 if (curr_blkoff != prev_blkoff) {
619 kunmap_atomic(kaddr, KM_USER0);
620 brelse(curr_bh);
621 ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr,
622 0, &curr_bh);
623 if (ret < 0)
624 goto out_header;
625 kaddr = kmap_atomic(curr_bh->b_page, KM_USER0);
626 }
627 curr_blkoff = prev_blkoff;
628 cp = nilfs_cpfile_block_get_checkpoint(
629 cpfile, curr, curr_bh, kaddr);
630 list = &cp->cp_snapshot_list;
631 prev = le64_to_cpu(list->ssl_prev);
632 }
633 kunmap_atomic(kaddr, KM_USER0);
634
635 if (prev != 0) {
636 ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
637 &prev_bh);
638 if (ret < 0)
639 goto out_curr;
640 } else {
641 prev_bh = header_bh;
642 get_bh(prev_bh);
643 }
644
645 kaddr = kmap_atomic(curr_bh->b_page, KM_USER0);
646 list = nilfs_cpfile_block_get_snapshot_list(
647 cpfile, curr, curr_bh, kaddr);
648 list->ssl_prev = cpu_to_le64(cno);
649 kunmap_atomic(kaddr, KM_USER0);
650
651 kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
652 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
653 cp->cp_snapshot_list.ssl_next = cpu_to_le64(curr);
654 cp->cp_snapshot_list.ssl_prev = cpu_to_le64(prev);
655 nilfs_checkpoint_set_snapshot(cp);
656 kunmap_atomic(kaddr, KM_USER0);
657
658 kaddr = kmap_atomic(prev_bh->b_page, KM_USER0);
659 list = nilfs_cpfile_block_get_snapshot_list(
660 cpfile, prev, prev_bh, kaddr);
661 list->ssl_next = cpu_to_le64(cno);
662 kunmap_atomic(kaddr, KM_USER0);
663
664 kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
665 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
666 le64_add_cpu(&header->ch_nsnapshots, 1);
667 kunmap_atomic(kaddr, KM_USER0);
668
669 nilfs_mdt_mark_buffer_dirty(prev_bh);
670 nilfs_mdt_mark_buffer_dirty(curr_bh);
671 nilfs_mdt_mark_buffer_dirty(cp_bh);
672 nilfs_mdt_mark_buffer_dirty(header_bh);
673 nilfs_mdt_mark_dirty(cpfile);
674
675 brelse(prev_bh);
676
677 out_curr:
678 brelse(curr_bh);
679
680 out_header:
681 brelse(header_bh);
682
683 out_cp:
684 brelse(cp_bh);
685
686 out_sem:
687 up_write(&NILFS_MDT(cpfile)->mi_sem);
688 return ret;
689}
690
691static int nilfs_cpfile_clear_snapshot(struct inode *cpfile, __u64 cno)
692{
693 struct buffer_head *header_bh, *next_bh, *prev_bh, *cp_bh;
694 struct nilfs_cpfile_header *header;
695 struct nilfs_checkpoint *cp;
696 struct nilfs_snapshot_list *list;
697 __u64 next, prev;
698 void *kaddr;
699 int ret;
700
Ryusuke Konishi1f5abe72009-04-06 19:01:55 -0700701 if (cno == 0)
702 return -ENOENT; /* checkpoint number 0 is invalid */
Koji Sato29619802009-04-06 19:01:31 -0700703 down_write(&NILFS_MDT(cpfile)->mi_sem);
704
705 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
706 if (ret < 0)
707 goto out_sem;
708 kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
709 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
710 if (nilfs_checkpoint_invalid(cp)) {
711 ret = -ENOENT;
712 kunmap_atomic(kaddr, KM_USER0);
713 goto out_cp;
714 }
715 if (!nilfs_checkpoint_snapshot(cp)) {
716 ret = 0;
717 kunmap_atomic(kaddr, KM_USER0);
718 goto out_cp;
719 }
720
721 list = &cp->cp_snapshot_list;
722 next = le64_to_cpu(list->ssl_next);
723 prev = le64_to_cpu(list->ssl_prev);
724 kunmap_atomic(kaddr, KM_USER0);
725
726 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
727 if (ret < 0)
728 goto out_cp;
729 if (next != 0) {
730 ret = nilfs_cpfile_get_checkpoint_block(cpfile, next, 0,
731 &next_bh);
732 if (ret < 0)
733 goto out_header;
734 } else {
735 next_bh = header_bh;
736 get_bh(next_bh);
737 }
738 if (prev != 0) {
739 ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
740 &prev_bh);
741 if (ret < 0)
742 goto out_next;
743 } else {
744 prev_bh = header_bh;
745 get_bh(prev_bh);
746 }
747
748 kaddr = kmap_atomic(next_bh->b_page, KM_USER0);
749 list = nilfs_cpfile_block_get_snapshot_list(
750 cpfile, next, next_bh, kaddr);
751 list->ssl_prev = cpu_to_le64(prev);
752 kunmap_atomic(kaddr, KM_USER0);
753
754 kaddr = kmap_atomic(prev_bh->b_page, KM_USER0);
755 list = nilfs_cpfile_block_get_snapshot_list(
756 cpfile, prev, prev_bh, kaddr);
757 list->ssl_next = cpu_to_le64(next);
758 kunmap_atomic(kaddr, KM_USER0);
759
760 kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
761 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
762 cp->cp_snapshot_list.ssl_next = cpu_to_le64(0);
763 cp->cp_snapshot_list.ssl_prev = cpu_to_le64(0);
764 nilfs_checkpoint_clear_snapshot(cp);
765 kunmap_atomic(kaddr, KM_USER0);
766
767 kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
768 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
769 le64_add_cpu(&header->ch_nsnapshots, -1);
770 kunmap_atomic(kaddr, KM_USER0);
771
772 nilfs_mdt_mark_buffer_dirty(next_bh);
773 nilfs_mdt_mark_buffer_dirty(prev_bh);
774 nilfs_mdt_mark_buffer_dirty(cp_bh);
775 nilfs_mdt_mark_buffer_dirty(header_bh);
776 nilfs_mdt_mark_dirty(cpfile);
777
778 brelse(prev_bh);
779
780 out_next:
781 brelse(next_bh);
782
783 out_header:
784 brelse(header_bh);
785
786 out_cp:
787 brelse(cp_bh);
788
789 out_sem:
790 up_write(&NILFS_MDT(cpfile)->mi_sem);
791 return ret;
792}
793
794/**
795 * nilfs_cpfile_is_snapshot -
796 * @cpfile: inode of checkpoint file
797 * @cno: checkpoint number
798 *
799 * Description:
800 *
801 * Return Value: On success, 1 is returned if the checkpoint specified by
802 * @cno is a snapshot, or 0 if not. On error, one of the following negative
803 * error codes is returned.
804 *
805 * %-EIO - I/O error.
806 *
807 * %-ENOMEM - Insufficient amount of memory available.
808 *
809 * %-ENOENT - No such checkpoint.
810 */
811int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
812{
813 struct buffer_head *bh;
814 struct nilfs_checkpoint *cp;
815 void *kaddr;
816 int ret;
817
Ryusuke Konishi1f5abe72009-04-06 19:01:55 -0700818 if (cno == 0)
819 return -ENOENT; /* checkpoint number 0 is invalid */
Koji Sato29619802009-04-06 19:01:31 -0700820 down_read(&NILFS_MDT(cpfile)->mi_sem);
821
822 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
823 if (ret < 0)
824 goto out;
825 kaddr = kmap_atomic(bh->b_page, KM_USER0);
826 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
827 ret = nilfs_checkpoint_snapshot(cp);
828 kunmap_atomic(kaddr, KM_USER0);
829 brelse(bh);
830
831 out:
832 up_read(&NILFS_MDT(cpfile)->mi_sem);
833 return ret;
834}
835
836/**
837 * nilfs_cpfile_change_cpmode - change checkpoint mode
838 * @cpfile: inode of checkpoint file
839 * @cno: checkpoint number
840 * @status: mode of checkpoint
841 *
842 * Description: nilfs_change_cpmode() changes the mode of the checkpoint
843 * specified by @cno. The mode @mode is NILFS_CHECKPOINT or NILFS_SNAPSHOT.
844 *
845 * Return Value: On success, 0 is returned. On error, one of the following
846 * negative error codes is returned.
847 *
848 * %-EIO - I/O error.
849 *
850 * %-ENOMEM - Insufficient amount of memory available.
851 *
852 * %-ENOENT - No such checkpoint.
853 */
854int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode)
855{
856 struct the_nilfs *nilfs;
857 int ret;
858
859 nilfs = NILFS_MDT(cpfile)->mi_nilfs;
860
861 switch (mode) {
862 case NILFS_CHECKPOINT:
863 /*
864 * Check for protecting existing snapshot mounts:
865 * bd_mount_sem is used to make this operation atomic and
866 * exclusive with a new mount job. Though it doesn't cover
867 * umount, it's enough for the purpose.
868 */
869 down(&nilfs->ns_bdev->bd_mount_sem);
870 if (nilfs_checkpoint_is_mounted(nilfs, cno, 1)) {
871 /* Current implementation does not have to protect
872 plain read-only mounts since they are exclusive
873 with a read/write mount and are protected from the
874 cleaner. */
875 ret = -EBUSY;
876 } else
877 ret = nilfs_cpfile_clear_snapshot(cpfile, cno);
878 up(&nilfs->ns_bdev->bd_mount_sem);
879 return ret;
880 case NILFS_SNAPSHOT:
881 return nilfs_cpfile_set_snapshot(cpfile, cno);
882 default:
883 return -EINVAL;
884 }
885}
886
887/**
888 * nilfs_cpfile_get_stat - get checkpoint statistics
889 * @cpfile: inode of checkpoint file
890 * @stat: pointer to a structure of checkpoint statistics
891 *
892 * Description: nilfs_cpfile_get_stat() returns information about checkpoints.
893 *
894 * Return Value: On success, 0 is returned, and checkpoints information is
895 * stored in the place pointed by @stat. On error, one of the following
896 * negative error codes is returned.
897 *
898 * %-EIO - I/O error.
899 *
900 * %-ENOMEM - Insufficient amount of memory available.
901 */
902int nilfs_cpfile_get_stat(struct inode *cpfile, struct nilfs_cpstat *cpstat)
903{
904 struct buffer_head *bh;
905 struct nilfs_cpfile_header *header;
906 void *kaddr;
907 int ret;
908
909 down_read(&NILFS_MDT(cpfile)->mi_sem);
910
911 ret = nilfs_cpfile_get_header_block(cpfile, &bh);
912 if (ret < 0)
913 goto out_sem;
914 kaddr = kmap_atomic(bh->b_page, KM_USER0);
915 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
916 cpstat->cs_cno = nilfs_mdt_cno(cpfile);
917 cpstat->cs_ncps = le64_to_cpu(header->ch_ncheckpoints);
918 cpstat->cs_nsss = le64_to_cpu(header->ch_nsnapshots);
919 kunmap_atomic(kaddr, KM_USER0);
920 brelse(bh);
921
922 out_sem:
923 up_read(&NILFS_MDT(cpfile)->mi_sem);
924 return ret;
925}