blob: cadd36b14d07058d9521b0f753f3411e5b5a388a [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)
Ryusuke Konishi62013ab2009-05-30 21:50:58 +0900314 goto out_header;
Koji Sato29619802009-04-06 19:01:31 -0700315 /* 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__);
Ryusuke Konishi62013ab2009-05-30 21:50:58 +0900347 goto out_header;
Koji Sato29619802009-04-06 19:01:31 -0700348 }
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 }
Ryusuke Konishi62013ab2009-05-30 21:50:58 +0900364
365 out_header:
Koji Sato29619802009-04-06 19:01:31 -0700366 brelse(header_bh);
367
368 out_sem:
369 up_write(&NILFS_MDT(cpfile)->mi_sem);
370 return ret;
371}
372
373static void nilfs_cpfile_checkpoint_to_cpinfo(struct inode *cpfile,
374 struct nilfs_checkpoint *cp,
375 struct nilfs_cpinfo *ci)
376{
377 ci->ci_flags = le32_to_cpu(cp->cp_flags);
378 ci->ci_cno = le64_to_cpu(cp->cp_cno);
379 ci->ci_create = le64_to_cpu(cp->cp_create);
380 ci->ci_nblk_inc = le64_to_cpu(cp->cp_nblk_inc);
381 ci->ci_inodes_count = le64_to_cpu(cp->cp_inodes_count);
382 ci->ci_blocks_count = le64_to_cpu(cp->cp_blocks_count);
383 ci->ci_next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
384}
385
Ryusuke Konishi76068c42009-04-06 19:01:50 -0700386static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop,
Koji Sato29619802009-04-06 19:01:31 -0700387 struct nilfs_cpinfo *ci, size_t nci)
388{
389 struct nilfs_checkpoint *cp;
390 struct buffer_head *bh;
391 size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
Ryusuke Konishi76068c42009-04-06 19:01:50 -0700392 __u64 cur_cno = nilfs_mdt_cno(cpfile), cno = *cnop;
Koji Sato29619802009-04-06 19:01:31 -0700393 void *kaddr;
394 int n, ret;
395 int ncps, i;
396
Ryusuke Konishi1f5abe72009-04-06 19:01:55 -0700397 if (cno == 0)
398 return -ENOENT; /* checkpoint number 0 is invalid */
Koji Sato29619802009-04-06 19:01:31 -0700399 down_read(&NILFS_MDT(cpfile)->mi_sem);
400
401 for (n = 0; cno < cur_cno && n < nci; cno += ncps) {
402 ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, cur_cno);
403 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
404 if (ret < 0) {
405 if (ret != -ENOENT)
406 goto out;
407 continue; /* skip hole */
408 }
409
410 kaddr = kmap_atomic(bh->b_page, KM_USER0);
411 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
412 for (i = 0; i < ncps && n < nci; i++, cp = (void *)cp + cpsz) {
413 if (!nilfs_checkpoint_invalid(cp))
414 nilfs_cpfile_checkpoint_to_cpinfo(
415 cpfile, cp, &ci[n++]);
416 }
417 kunmap_atomic(kaddr, KM_USER0);
418 brelse(bh);
419 }
420
421 ret = n;
Ryusuke Konishi76068c42009-04-06 19:01:50 -0700422 if (n > 0)
423 *cnop = ci[n - 1].ci_cno + 1;
Koji Sato29619802009-04-06 19:01:31 -0700424
425 out:
426 up_read(&NILFS_MDT(cpfile)->mi_sem);
427 return ret;
428}
429
Ryusuke Konishib028fcf2009-04-06 19:01:47 -0700430static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
Koji Sato29619802009-04-06 19:01:31 -0700431 struct nilfs_cpinfo *ci, size_t nci)
432{
433 struct buffer_head *bh;
434 struct nilfs_cpfile_header *header;
435 struct nilfs_checkpoint *cp;
Ryusuke Konishib028fcf2009-04-06 19:01:47 -0700436 __u64 curr = *cnop, next;
Koji Sato29619802009-04-06 19:01:31 -0700437 unsigned long curr_blkoff, next_blkoff;
438 void *kaddr;
Ryusuke Konishi7fa10d22009-04-06 19:01:48 -0700439 int n = 0, ret;
Koji Sato29619802009-04-06 19:01:31 -0700440
441 down_read(&NILFS_MDT(cpfile)->mi_sem);
442
Ryusuke Konishib028fcf2009-04-06 19:01:47 -0700443 if (curr == 0) {
Koji Sato29619802009-04-06 19:01:31 -0700444 ret = nilfs_cpfile_get_header_block(cpfile, &bh);
445 if (ret < 0)
446 goto out;
447 kaddr = kmap_atomic(bh->b_page, KM_USER0);
448 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
449 curr = le64_to_cpu(header->ch_snapshot_list.ssl_next);
450 kunmap_atomic(kaddr, KM_USER0);
451 brelse(bh);
452 if (curr == 0) {
453 ret = 0;
454 goto out;
455 }
Ryusuke Konishib028fcf2009-04-06 19:01:47 -0700456 } else if (unlikely(curr == ~(__u64)0)) {
457 ret = 0;
458 goto out;
459 }
460
Koji Sato29619802009-04-06 19:01:31 -0700461 curr_blkoff = nilfs_cpfile_get_blkoff(cpfile, curr);
462 ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr, 0, &bh);
Ryusuke Konishi7fa10d22009-04-06 19:01:48 -0700463 if (unlikely(ret < 0)) {
464 if (ret == -ENOENT)
465 ret = 0; /* No snapshots (started from a hole block) */
Koji Sato29619802009-04-06 19:01:31 -0700466 goto out;
Ryusuke Konishi7fa10d22009-04-06 19:01:48 -0700467 }
Koji Sato29619802009-04-06 19:01:31 -0700468 kaddr = kmap_atomic(bh->b_page, KM_USER0);
Ryusuke Konishi7fa10d22009-04-06 19:01:48 -0700469 while (n < nci) {
470 cp = nilfs_cpfile_block_get_checkpoint(cpfile, curr, bh, kaddr);
471 curr = ~(__u64)0; /* Terminator */
472 if (unlikely(nilfs_checkpoint_invalid(cp) ||
473 !nilfs_checkpoint_snapshot(cp)))
Koji Sato29619802009-04-06 19:01:31 -0700474 break;
Ryusuke Konishi7fa10d22009-04-06 19:01:48 -0700475 nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, &ci[n++]);
476 next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
477 if (next == 0)
478 break; /* reach end of the snapshot list */
479
Koji Sato29619802009-04-06 19:01:31 -0700480 next_blkoff = nilfs_cpfile_get_blkoff(cpfile, next);
481 if (curr_blkoff != next_blkoff) {
482 kunmap_atomic(kaddr, KM_USER0);
483 brelse(bh);
484 ret = nilfs_cpfile_get_checkpoint_block(cpfile, next,
485 0, &bh);
Ryusuke Konishi7fa10d22009-04-06 19:01:48 -0700486 if (unlikely(ret < 0)) {
487 WARN_ON(ret == -ENOENT);
Koji Sato29619802009-04-06 19:01:31 -0700488 goto out;
Ryusuke Konishi7fa10d22009-04-06 19:01:48 -0700489 }
Koji Sato29619802009-04-06 19:01:31 -0700490 kaddr = kmap_atomic(bh->b_page, KM_USER0);
491 }
492 curr = next;
493 curr_blkoff = next_blkoff;
494 }
495 kunmap_atomic(kaddr, KM_USER0);
496 brelse(bh);
Ryusuke Konishib028fcf2009-04-06 19:01:47 -0700497 *cnop = curr;
Koji Sato29619802009-04-06 19:01:31 -0700498 ret = n;
499
500 out:
501 up_read(&NILFS_MDT(cpfile)->mi_sem);
502 return ret;
503}
504
505/**
506 * nilfs_cpfile_get_cpinfo -
507 * @cpfile:
508 * @cno:
509 * @ci:
510 * @nci:
511 */
Ryusuke Konishib028fcf2009-04-06 19:01:47 -0700512
513ssize_t nilfs_cpfile_get_cpinfo(struct inode *cpfile, __u64 *cnop, int mode,
Koji Sato29619802009-04-06 19:01:31 -0700514 struct nilfs_cpinfo *ci, size_t nci)
515{
516 switch (mode) {
517 case NILFS_CHECKPOINT:
Ryusuke Konishi76068c42009-04-06 19:01:50 -0700518 return nilfs_cpfile_do_get_cpinfo(cpfile, cnop, ci, nci);
Koji Sato29619802009-04-06 19:01:31 -0700519 case NILFS_SNAPSHOT:
Ryusuke Konishib028fcf2009-04-06 19:01:47 -0700520 return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, ci, nci);
Koji Sato29619802009-04-06 19:01:31 -0700521 default:
522 return -EINVAL;
523 }
524}
525
526/**
527 * nilfs_cpfile_delete_checkpoint -
528 * @cpfile:
529 * @cno:
530 */
531int nilfs_cpfile_delete_checkpoint(struct inode *cpfile, __u64 cno)
532{
533 struct nilfs_cpinfo ci;
Ryusuke Konishi76068c42009-04-06 19:01:50 -0700534 __u64 tcno = cno;
Koji Sato29619802009-04-06 19:01:31 -0700535 ssize_t nci;
536 int ret;
537
Ryusuke Konishi76068c42009-04-06 19:01:50 -0700538 nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, 1);
Koji Sato29619802009-04-06 19:01:31 -0700539 if (nci < 0)
540 return nci;
541 else if (nci == 0 || ci.ci_cno != cno)
542 return -ENOENT;
543
544 /* cannot delete the latest checkpoint nor snapshots */
545 ret = nilfs_cpinfo_snapshot(&ci);
546 if (ret < 0)
547 return ret;
548 else if (ret > 0 || cno == nilfs_mdt_cno(cpfile) - 1)
549 return -EPERM;
550
551 return nilfs_cpfile_delete_checkpoints(cpfile, cno, cno + 1);
552}
553
554static struct nilfs_snapshot_list *
555nilfs_cpfile_block_get_snapshot_list(const struct inode *cpfile,
556 __u64 cno,
557 struct buffer_head *bh,
558 void *kaddr)
559{
560 struct nilfs_cpfile_header *header;
561 struct nilfs_checkpoint *cp;
562 struct nilfs_snapshot_list *list;
563
564 if (cno != 0) {
565 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
566 list = &cp->cp_snapshot_list;
567 } else {
568 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
569 list = &header->ch_snapshot_list;
570 }
571 return list;
572}
573
574static int nilfs_cpfile_set_snapshot(struct inode *cpfile, __u64 cno)
575{
576 struct buffer_head *header_bh, *curr_bh, *prev_bh, *cp_bh;
577 struct nilfs_cpfile_header *header;
578 struct nilfs_checkpoint *cp;
579 struct nilfs_snapshot_list *list;
580 __u64 curr, prev;
581 unsigned long curr_blkoff, prev_blkoff;
582 void *kaddr;
583 int ret;
584
Ryusuke Konishi1f5abe72009-04-06 19:01:55 -0700585 if (cno == 0)
586 return -ENOENT; /* checkpoint number 0 is invalid */
Koji Sato29619802009-04-06 19:01:31 -0700587 down_write(&NILFS_MDT(cpfile)->mi_sem);
588
589 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
590 if (ret < 0)
591 goto out_sem;
592 kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
593 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
594 if (nilfs_checkpoint_invalid(cp)) {
595 ret = -ENOENT;
596 kunmap_atomic(kaddr, KM_USER0);
597 goto out_cp;
598 }
599 if (nilfs_checkpoint_snapshot(cp)) {
600 ret = 0;
601 kunmap_atomic(kaddr, KM_USER0);
602 goto out_cp;
603 }
604 kunmap_atomic(kaddr, KM_USER0);
605
606 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
607 if (ret < 0)
608 goto out_cp;
609 kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
610 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
611 list = &header->ch_snapshot_list;
612 curr_bh = header_bh;
613 get_bh(curr_bh);
614 curr = 0;
615 curr_blkoff = 0;
616 prev = le64_to_cpu(list->ssl_prev);
617 while (prev > cno) {
618 prev_blkoff = nilfs_cpfile_get_blkoff(cpfile, prev);
619 curr = prev;
620 if (curr_blkoff != prev_blkoff) {
621 kunmap_atomic(kaddr, KM_USER0);
622 brelse(curr_bh);
623 ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr,
624 0, &curr_bh);
625 if (ret < 0)
626 goto out_header;
627 kaddr = kmap_atomic(curr_bh->b_page, KM_USER0);
628 }
629 curr_blkoff = prev_blkoff;
630 cp = nilfs_cpfile_block_get_checkpoint(
631 cpfile, curr, curr_bh, kaddr);
632 list = &cp->cp_snapshot_list;
633 prev = le64_to_cpu(list->ssl_prev);
634 }
635 kunmap_atomic(kaddr, KM_USER0);
636
637 if (prev != 0) {
638 ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
639 &prev_bh);
640 if (ret < 0)
641 goto out_curr;
642 } else {
643 prev_bh = header_bh;
644 get_bh(prev_bh);
645 }
646
647 kaddr = kmap_atomic(curr_bh->b_page, KM_USER0);
648 list = nilfs_cpfile_block_get_snapshot_list(
649 cpfile, curr, curr_bh, kaddr);
650 list->ssl_prev = cpu_to_le64(cno);
651 kunmap_atomic(kaddr, KM_USER0);
652
653 kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
654 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
655 cp->cp_snapshot_list.ssl_next = cpu_to_le64(curr);
656 cp->cp_snapshot_list.ssl_prev = cpu_to_le64(prev);
657 nilfs_checkpoint_set_snapshot(cp);
658 kunmap_atomic(kaddr, KM_USER0);
659
660 kaddr = kmap_atomic(prev_bh->b_page, KM_USER0);
661 list = nilfs_cpfile_block_get_snapshot_list(
662 cpfile, prev, prev_bh, kaddr);
663 list->ssl_next = cpu_to_le64(cno);
664 kunmap_atomic(kaddr, KM_USER0);
665
666 kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
667 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
668 le64_add_cpu(&header->ch_nsnapshots, 1);
669 kunmap_atomic(kaddr, KM_USER0);
670
671 nilfs_mdt_mark_buffer_dirty(prev_bh);
672 nilfs_mdt_mark_buffer_dirty(curr_bh);
673 nilfs_mdt_mark_buffer_dirty(cp_bh);
674 nilfs_mdt_mark_buffer_dirty(header_bh);
675 nilfs_mdt_mark_dirty(cpfile);
676
677 brelse(prev_bh);
678
679 out_curr:
680 brelse(curr_bh);
681
682 out_header:
683 brelse(header_bh);
684
685 out_cp:
686 brelse(cp_bh);
687
688 out_sem:
689 up_write(&NILFS_MDT(cpfile)->mi_sem);
690 return ret;
691}
692
693static int nilfs_cpfile_clear_snapshot(struct inode *cpfile, __u64 cno)
694{
695 struct buffer_head *header_bh, *next_bh, *prev_bh, *cp_bh;
696 struct nilfs_cpfile_header *header;
697 struct nilfs_checkpoint *cp;
698 struct nilfs_snapshot_list *list;
699 __u64 next, prev;
700 void *kaddr;
701 int ret;
702
Ryusuke Konishi1f5abe72009-04-06 19:01:55 -0700703 if (cno == 0)
704 return -ENOENT; /* checkpoint number 0 is invalid */
Koji Sato29619802009-04-06 19:01:31 -0700705 down_write(&NILFS_MDT(cpfile)->mi_sem);
706
707 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
708 if (ret < 0)
709 goto out_sem;
710 kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
711 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
712 if (nilfs_checkpoint_invalid(cp)) {
713 ret = -ENOENT;
714 kunmap_atomic(kaddr, KM_USER0);
715 goto out_cp;
716 }
717 if (!nilfs_checkpoint_snapshot(cp)) {
718 ret = 0;
719 kunmap_atomic(kaddr, KM_USER0);
720 goto out_cp;
721 }
722
723 list = &cp->cp_snapshot_list;
724 next = le64_to_cpu(list->ssl_next);
725 prev = le64_to_cpu(list->ssl_prev);
726 kunmap_atomic(kaddr, KM_USER0);
727
728 ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
729 if (ret < 0)
730 goto out_cp;
731 if (next != 0) {
732 ret = nilfs_cpfile_get_checkpoint_block(cpfile, next, 0,
733 &next_bh);
734 if (ret < 0)
735 goto out_header;
736 } else {
737 next_bh = header_bh;
738 get_bh(next_bh);
739 }
740 if (prev != 0) {
741 ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
742 &prev_bh);
743 if (ret < 0)
744 goto out_next;
745 } else {
746 prev_bh = header_bh;
747 get_bh(prev_bh);
748 }
749
750 kaddr = kmap_atomic(next_bh->b_page, KM_USER0);
751 list = nilfs_cpfile_block_get_snapshot_list(
752 cpfile, next, next_bh, kaddr);
753 list->ssl_prev = cpu_to_le64(prev);
754 kunmap_atomic(kaddr, KM_USER0);
755
756 kaddr = kmap_atomic(prev_bh->b_page, KM_USER0);
757 list = nilfs_cpfile_block_get_snapshot_list(
758 cpfile, prev, prev_bh, kaddr);
759 list->ssl_next = cpu_to_le64(next);
760 kunmap_atomic(kaddr, KM_USER0);
761
762 kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
763 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
764 cp->cp_snapshot_list.ssl_next = cpu_to_le64(0);
765 cp->cp_snapshot_list.ssl_prev = cpu_to_le64(0);
766 nilfs_checkpoint_clear_snapshot(cp);
767 kunmap_atomic(kaddr, KM_USER0);
768
769 kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
770 header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
771 le64_add_cpu(&header->ch_nsnapshots, -1);
772 kunmap_atomic(kaddr, KM_USER0);
773
774 nilfs_mdt_mark_buffer_dirty(next_bh);
775 nilfs_mdt_mark_buffer_dirty(prev_bh);
776 nilfs_mdt_mark_buffer_dirty(cp_bh);
777 nilfs_mdt_mark_buffer_dirty(header_bh);
778 nilfs_mdt_mark_dirty(cpfile);
779
780 brelse(prev_bh);
781
782 out_next:
783 brelse(next_bh);
784
785 out_header:
786 brelse(header_bh);
787
788 out_cp:
789 brelse(cp_bh);
790
791 out_sem:
792 up_write(&NILFS_MDT(cpfile)->mi_sem);
793 return ret;
794}
795
796/**
797 * nilfs_cpfile_is_snapshot -
798 * @cpfile: inode of checkpoint file
799 * @cno: checkpoint number
800 *
801 * Description:
802 *
803 * Return Value: On success, 1 is returned if the checkpoint specified by
804 * @cno is a snapshot, or 0 if not. On error, one of the following negative
805 * error codes is returned.
806 *
807 * %-EIO - I/O error.
808 *
809 * %-ENOMEM - Insufficient amount of memory available.
810 *
811 * %-ENOENT - No such checkpoint.
812 */
813int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
814{
815 struct buffer_head *bh;
816 struct nilfs_checkpoint *cp;
817 void *kaddr;
818 int ret;
819
Ryusuke Konishi1f5abe72009-04-06 19:01:55 -0700820 if (cno == 0)
821 return -ENOENT; /* checkpoint number 0 is invalid */
Koji Sato29619802009-04-06 19:01:31 -0700822 down_read(&NILFS_MDT(cpfile)->mi_sem);
823
824 ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
825 if (ret < 0)
826 goto out;
827 kaddr = kmap_atomic(bh->b_page, KM_USER0);
828 cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
829 ret = nilfs_checkpoint_snapshot(cp);
830 kunmap_atomic(kaddr, KM_USER0);
831 brelse(bh);
832
833 out:
834 up_read(&NILFS_MDT(cpfile)->mi_sem);
835 return ret;
836}
837
838/**
839 * nilfs_cpfile_change_cpmode - change checkpoint mode
840 * @cpfile: inode of checkpoint file
841 * @cno: checkpoint number
842 * @status: mode of checkpoint
843 *
844 * Description: nilfs_change_cpmode() changes the mode of the checkpoint
845 * specified by @cno. The mode @mode is NILFS_CHECKPOINT or NILFS_SNAPSHOT.
846 *
847 * Return Value: On success, 0 is returned. On error, one of the following
848 * negative error codes is returned.
849 *
850 * %-EIO - I/O error.
851 *
852 * %-ENOMEM - Insufficient amount of memory available.
853 *
854 * %-ENOENT - No such checkpoint.
855 */
856int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode)
857{
858 struct the_nilfs *nilfs;
859 int ret;
860
861 nilfs = NILFS_MDT(cpfile)->mi_nilfs;
862
863 switch (mode) {
864 case NILFS_CHECKPOINT:
865 /*
866 * Check for protecting existing snapshot mounts:
Ryusuke Konishiaa7dfb82009-06-08 01:39:33 +0900867 * ns_mount_mutex is used to make this operation atomic and
Koji Sato29619802009-04-06 19:01:31 -0700868 * exclusive with a new mount job. Though it doesn't cover
869 * umount, it's enough for the purpose.
870 */
Ryusuke Konishiaa7dfb82009-06-08 01:39:33 +0900871 mutex_lock(&nilfs->ns_mount_mutex);
Koji Sato29619802009-04-06 19:01:31 -0700872 if (nilfs_checkpoint_is_mounted(nilfs, cno, 1)) {
873 /* Current implementation does not have to protect
874 plain read-only mounts since they are exclusive
875 with a read/write mount and are protected from the
876 cleaner. */
877 ret = -EBUSY;
878 } else
879 ret = nilfs_cpfile_clear_snapshot(cpfile, cno);
Ryusuke Konishiaa7dfb82009-06-08 01:39:33 +0900880 mutex_unlock(&nilfs->ns_mount_mutex);
Koji Sato29619802009-04-06 19:01:31 -0700881 return ret;
882 case NILFS_SNAPSHOT:
883 return nilfs_cpfile_set_snapshot(cpfile, cno);
884 default:
885 return -EINVAL;
886 }
887}
888
889/**
890 * nilfs_cpfile_get_stat - get checkpoint statistics
891 * @cpfile: inode of checkpoint file
892 * @stat: pointer to a structure of checkpoint statistics
893 *
894 * Description: nilfs_cpfile_get_stat() returns information about checkpoints.
895 *
896 * Return Value: On success, 0 is returned, and checkpoints information is
897 * stored in the place pointed by @stat. On error, one of the following
898 * negative error codes is returned.
899 *
900 * %-EIO - I/O error.
901 *
902 * %-ENOMEM - Insufficient amount of memory available.
903 */
904int nilfs_cpfile_get_stat(struct inode *cpfile, struct nilfs_cpstat *cpstat)
905{
906 struct buffer_head *bh;
907 struct nilfs_cpfile_header *header;
908 void *kaddr;
909 int ret;
910
911 down_read(&NILFS_MDT(cpfile)->mi_sem);
912
913 ret = nilfs_cpfile_get_header_block(cpfile, &bh);
914 if (ret < 0)
915 goto out_sem;
916 kaddr = kmap_atomic(bh->b_page, KM_USER0);
917 header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
918 cpstat->cs_cno = nilfs_mdt_cno(cpfile);
919 cpstat->cs_ncps = le64_to_cpu(header->ch_ncheckpoints);
920 cpstat->cs_nsss = le64_to_cpu(header->ch_nsnapshots);
921 kunmap_atomic(kaddr, KM_USER0);
922 brelse(bh);
923
924 out_sem:
925 up_read(&NILFS_MDT(cpfile)->mi_sem);
926 return ret;
927}