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1/*
2 * recovery.c - NILFS recovery logic
3 *
4 * Copyright (C) 2005-2008 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 Ryusuke Konishi <ryusuke@osrg.net>
21 */
22
23#include <linux/buffer_head.h>
24#include <linux/blkdev.h>
25#include <linux/swap.h>
26#include <linux/slab.h>
27#include <linux/crc32.h>
28#include "nilfs.h"
29#include "segment.h"
30#include "sufile.h"
31#include "page.h"
32#include "segbuf.h"
33
34/*
35 * Segment check result
36 */
37enum {
38 NILFS_SEG_VALID,
39 NILFS_SEG_NO_SUPER_ROOT,
40 NILFS_SEG_FAIL_IO,
41 NILFS_SEG_FAIL_MAGIC,
42 NILFS_SEG_FAIL_SEQ,
43 NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT,
44 NILFS_SEG_FAIL_CHECKSUM_FULL,
45 NILFS_SEG_FAIL_CONSISTENCY,
46};
47
48/* work structure for recovery */
49struct nilfs_recovery_block {
50 ino_t ino; /* Inode number of the file that this block
51 belongs to */
52 sector_t blocknr; /* block number */
53 __u64 vblocknr; /* virtual block number */
54 unsigned long blkoff; /* File offset of the data block (per block) */
55 struct list_head list;
56};
57
58
59static int nilfs_warn_segment_error(int err)
60{
61 switch (err) {
62 case NILFS_SEG_FAIL_IO:
63 printk(KERN_WARNING
64 "NILFS warning: I/O error on loading last segment\n");
65 return -EIO;
66 case NILFS_SEG_FAIL_MAGIC:
67 printk(KERN_WARNING
68 "NILFS warning: Segment magic number invalid\n");
69 break;
70 case NILFS_SEG_FAIL_SEQ:
71 printk(KERN_WARNING
72 "NILFS warning: Sequence number mismatch\n");
73 break;
74 case NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT:
75 printk(KERN_WARNING
76 "NILFS warning: Checksum error in super root\n");
77 break;
78 case NILFS_SEG_FAIL_CHECKSUM_FULL:
79 printk(KERN_WARNING
80 "NILFS warning: Checksum error in segment payload\n");
81 break;
82 case NILFS_SEG_FAIL_CONSISTENCY:
83 printk(KERN_WARNING
84 "NILFS warning: Inconsistent segment\n");
85 break;
86 case NILFS_SEG_NO_SUPER_ROOT:
87 printk(KERN_WARNING
88 "NILFS warning: No super root in the last segment\n");
89 break;
90 }
91 return -EINVAL;
92}
93
94/**
95 * nilfs_compute_checksum - compute checksum of blocks continuously
96 * @nilfs: nilfs object
97 * @bhs: buffer head of start block
98 * @sum: place to store result
99 * @offset: offset bytes in the first block
100 * @check_bytes: number of bytes to be checked
101 * @start: DBN of start block
102 * @nblock: number of blocks to be checked
103 */
104static int nilfs_compute_checksum(struct the_nilfs *nilfs,
105 struct buffer_head *bhs, u32 *sum,
106 unsigned long offset, u64 check_bytes,
107 sector_t start, unsigned long nblock)
108{
109 unsigned int blocksize = nilfs->ns_blocksize;
110 unsigned long size;
111 u32 crc;
112
113 BUG_ON(offset >= blocksize);
114 check_bytes -= offset;
115 size = min_t(u64, check_bytes, blocksize - offset);
116 crc = crc32_le(nilfs->ns_crc_seed,
117 (unsigned char *)bhs->b_data + offset, size);
118 if (--nblock > 0) {
119 do {
120 struct buffer_head *bh;
121
122 bh = __bread(nilfs->ns_bdev, ++start, blocksize);
123 if (!bh)
124 return -EIO;
125 check_bytes -= size;
126 size = min_t(u64, check_bytes, blocksize);
127 crc = crc32_le(crc, bh->b_data, size);
128 brelse(bh);
129 } while (--nblock > 0);
130 }
131 *sum = crc;
132 return 0;
133}
134
135/**
136 * nilfs_read_super_root_block - read super root block
137 * @nilfs: nilfs object
138 * @sr_block: disk block number of the super root block
139 * @pbh: address of a buffer_head pointer to return super root buffer
140 * @check: CRC check flag
141 */
142int nilfs_read_super_root_block(struct the_nilfs *nilfs, sector_t sr_block,
143 struct buffer_head **pbh, int check)
144{
145 struct buffer_head *bh_sr;
146 struct nilfs_super_root *sr;
147 u32 crc;
148 int ret;
149
150 *pbh = NULL;
151 bh_sr = __bread(nilfs->ns_bdev, sr_block, nilfs->ns_blocksize);
152 if (unlikely(!bh_sr)) {
153 ret = NILFS_SEG_FAIL_IO;
154 goto failed;
155 }
156
157 sr = (struct nilfs_super_root *)bh_sr->b_data;
158 if (check) {
159 unsigned bytes = le16_to_cpu(sr->sr_bytes);
160
161 if (bytes == 0 || bytes > nilfs->ns_blocksize) {
162 ret = NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT;
163 goto failed_bh;
164 }
165 if (nilfs_compute_checksum(
166 nilfs, bh_sr, &crc, sizeof(sr->sr_sum), bytes,
167 sr_block, 1)) {
168 ret = NILFS_SEG_FAIL_IO;
169 goto failed_bh;
170 }
171 if (crc != le32_to_cpu(sr->sr_sum)) {
172 ret = NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT;
173 goto failed_bh;
174 }
175 }
176 *pbh = bh_sr;
177 return 0;
178
179 failed_bh:
180 brelse(bh_sr);
181
182 failed:
183 return nilfs_warn_segment_error(ret);
184}
185
186/**
187 * nilfs_read_log_header - read summary header of the specified log
188 * @nilfs: nilfs object
189 * @start_blocknr: start block number of the log
190 * @sum: pointer to return segment summary structure
191 */
192static struct buffer_head *
193nilfs_read_log_header(struct the_nilfs *nilfs, sector_t start_blocknr,
194 struct nilfs_segment_summary **sum)
195{
196 struct buffer_head *bh_sum;
197
198 bh_sum = __bread(nilfs->ns_bdev, start_blocknr, nilfs->ns_blocksize);
199 if (bh_sum)
200 *sum = (struct nilfs_segment_summary *)bh_sum->b_data;
201 return bh_sum;
202}
203
204/**
205 * nilfs_validate_log - verify consistency of log
206 * @nilfs: nilfs object
207 * @seg_seq: sequence number of segment
208 * @bh_sum: buffer head of summary block
209 * @sum: segment summary struct
210 */
211static int nilfs_validate_log(struct the_nilfs *nilfs, u64 seg_seq,
212 struct buffer_head *bh_sum,
213 struct nilfs_segment_summary *sum)
214{
215 unsigned long nblock;
216 u32 crc;
217 int ret;
218
219 ret = NILFS_SEG_FAIL_MAGIC;
220 if (le32_to_cpu(sum->ss_magic) != NILFS_SEGSUM_MAGIC)
221 goto out;
222
223 ret = NILFS_SEG_FAIL_SEQ;
224 if (le64_to_cpu(sum->ss_seq) != seg_seq)
225 goto out;
226
227 nblock = le32_to_cpu(sum->ss_nblocks);
228 ret = NILFS_SEG_FAIL_CONSISTENCY;
229 if (unlikely(nblock == 0 || nblock > nilfs->ns_blocks_per_segment))
230 /* This limits the number of blocks read in the CRC check */
231 goto out;
232
233 ret = NILFS_SEG_FAIL_IO;
234 if (nilfs_compute_checksum(nilfs, bh_sum, &crc, sizeof(sum->ss_datasum),
235 ((u64)nblock << nilfs->ns_blocksize_bits),
236 bh_sum->b_blocknr, nblock))
237 goto out;
238
239 ret = NILFS_SEG_FAIL_CHECKSUM_FULL;
240 if (crc != le32_to_cpu(sum->ss_datasum))
241 goto out;
242 ret = 0;
243out:
244 return ret;
245}
246
247/**
248 * nilfs_read_summary_info - read an item on summary blocks of a log
249 * @nilfs: nilfs object
250 * @pbh: the current buffer head on summary blocks [in, out]
251 * @offset: the current byte offset on summary blocks [in, out]
252 * @bytes: byte size of the item to be read
253 */
254static void *nilfs_read_summary_info(struct the_nilfs *nilfs,
255 struct buffer_head **pbh,
256 unsigned int *offset, unsigned int bytes)
257{
258 void *ptr;
259 sector_t blocknr;
260
261 BUG_ON((*pbh)->b_size < *offset);
262 if (bytes > (*pbh)->b_size - *offset) {
263 blocknr = (*pbh)->b_blocknr;
264 brelse(*pbh);
265 *pbh = __bread(nilfs->ns_bdev, blocknr + 1,
266 nilfs->ns_blocksize);
267 if (unlikely(!*pbh))
268 return NULL;
269 *offset = 0;
270 }
271 ptr = (*pbh)->b_data + *offset;
272 *offset += bytes;
273 return ptr;
274}
275
276/**
277 * nilfs_skip_summary_info - skip items on summary blocks of a log
278 * @nilfs: nilfs object
279 * @pbh: the current buffer head on summary blocks [in, out]
280 * @offset: the current byte offset on summary blocks [in, out]
281 * @bytes: byte size of the item to be skipped
282 * @count: number of items to be skipped
283 */
284static void nilfs_skip_summary_info(struct the_nilfs *nilfs,
285 struct buffer_head **pbh,
286 unsigned int *offset, unsigned int bytes,
287 unsigned long count)
288{
289 unsigned int rest_item_in_current_block
290 = ((*pbh)->b_size - *offset) / bytes;
291
292 if (count <= rest_item_in_current_block) {
293 *offset += bytes * count;
294 } else {
295 sector_t blocknr = (*pbh)->b_blocknr;
296 unsigned int nitem_per_block = (*pbh)->b_size / bytes;
297 unsigned int bcnt;
298
299 count -= rest_item_in_current_block;
300 bcnt = DIV_ROUND_UP(count, nitem_per_block);
301 *offset = bytes * (count - (bcnt - 1) * nitem_per_block);
302
303 brelse(*pbh);
304 *pbh = __bread(nilfs->ns_bdev, blocknr + bcnt,
305 nilfs->ns_blocksize);
306 }
307}
308
309/**
310 * nilfs_scan_dsync_log - get block information of a log written for data sync
311 * @nilfs: nilfs object
312 * @start_blocknr: start block number of the log
313 * @sum: log summary information
314 * @head: list head to add nilfs_recovery_block struct
315 */
316static int nilfs_scan_dsync_log(struct the_nilfs *nilfs, sector_t start_blocknr,
317 struct nilfs_segment_summary *sum,
318 struct list_head *head)
319{
320 struct buffer_head *bh;
321 unsigned int offset;
322 u32 nfinfo, sumbytes;
323 sector_t blocknr;
324 ino_t ino;
325 int err = -EIO;
326
327 nfinfo = le32_to_cpu(sum->ss_nfinfo);
328 if (!nfinfo)
329 return 0;
330
331 sumbytes = le32_to_cpu(sum->ss_sumbytes);
332 blocknr = start_blocknr + DIV_ROUND_UP(sumbytes, nilfs->ns_blocksize);
333 bh = __bread(nilfs->ns_bdev, start_blocknr, nilfs->ns_blocksize);
334 if (unlikely(!bh))
335 goto out;
336
337 offset = le16_to_cpu(sum->ss_bytes);
338 for (;;) {
339 unsigned long nblocks, ndatablk, nnodeblk;
340 struct nilfs_finfo *finfo;
341
342 finfo = nilfs_read_summary_info(nilfs, &bh, &offset,
343 sizeof(*finfo));
344 if (unlikely(!finfo))
345 goto out;
346
347 ino = le64_to_cpu(finfo->fi_ino);
348 nblocks = le32_to_cpu(finfo->fi_nblocks);
349 ndatablk = le32_to_cpu(finfo->fi_ndatablk);
350 nnodeblk = nblocks - ndatablk;
351
352 while (ndatablk-- > 0) {
353 struct nilfs_recovery_block *rb;
354 struct nilfs_binfo_v *binfo;
355
356 binfo = nilfs_read_summary_info(nilfs, &bh, &offset,
357 sizeof(*binfo));
358 if (unlikely(!binfo))
359 goto out;
360
361 rb = kmalloc(sizeof(*rb), GFP_NOFS);
362 if (unlikely(!rb)) {
363 err = -ENOMEM;
364 goto out;
365 }
366 rb->ino = ino;
367 rb->blocknr = blocknr++;
368 rb->vblocknr = le64_to_cpu(binfo->bi_vblocknr);
369 rb->blkoff = le64_to_cpu(binfo->bi_blkoff);
370 /* INIT_LIST_HEAD(&rb->list); */
371 list_add_tail(&rb->list, head);
372 }
373 if (--nfinfo == 0)
374 break;
375 blocknr += nnodeblk; /* always 0 for data sync logs */
376 nilfs_skip_summary_info(nilfs, &bh, &offset, sizeof(__le64),
377 nnodeblk);
378 if (unlikely(!bh))
379 goto out;
380 }
381 err = 0;
382 out:
383 brelse(bh); /* brelse(NULL) is just ignored */
384 return err;
385}
386
387static void dispose_recovery_list(struct list_head *head)
388{
389 while (!list_empty(head)) {
390 struct nilfs_recovery_block *rb;
391
392 rb = list_first_entry(head, struct nilfs_recovery_block, list);
393 list_del(&rb->list);
394 kfree(rb);
395 }
396}
397
398struct nilfs_segment_entry {
399 struct list_head list;
400 __u64 segnum;
401};
402
403static int nilfs_segment_list_add(struct list_head *head, __u64 segnum)
404{
405 struct nilfs_segment_entry *ent = kmalloc(sizeof(*ent), GFP_NOFS);
406
407 if (unlikely(!ent))
408 return -ENOMEM;
409
410 ent->segnum = segnum;
411 INIT_LIST_HEAD(&ent->list);
412 list_add_tail(&ent->list, head);
413 return 0;
414}
415
416void nilfs_dispose_segment_list(struct list_head *head)
417{
418 while (!list_empty(head)) {
419 struct nilfs_segment_entry *ent;
420
421 ent = list_first_entry(head, struct nilfs_segment_entry, list);
422 list_del(&ent->list);
423 kfree(ent);
424 }
425}
426
427static int nilfs_prepare_segment_for_recovery(struct the_nilfs *nilfs,
428 struct super_block *sb,
429 struct nilfs_recovery_info *ri)
430{
431 struct list_head *head = &ri->ri_used_segments;
432 struct nilfs_segment_entry *ent, *n;
433 struct inode *sufile = nilfs->ns_sufile;
434 __u64 segnum[4];
435 int err;
436 int i;
437
438 segnum[0] = nilfs->ns_segnum;
439 segnum[1] = nilfs->ns_nextnum;
440 segnum[2] = ri->ri_segnum;
441 segnum[3] = ri->ri_nextnum;
442
443 /*
444 * Releasing the next segment of the latest super root.
445 * The next segment is invalidated by this recovery.
446 */
447 err = nilfs_sufile_free(sufile, segnum[1]);
448 if (unlikely(err))
449 goto failed;
450
451 for (i = 1; i < 4; i++) {
452 err = nilfs_segment_list_add(head, segnum[i]);
453 if (unlikely(err))
454 goto failed;
455 }
456
457 /*
458 * Collecting segments written after the latest super root.
459 * These are marked dirty to avoid being reallocated in the next write.
460 */
461 list_for_each_entry_safe(ent, n, head, list) {
462 if (ent->segnum != segnum[0]) {
463 err = nilfs_sufile_scrap(sufile, ent->segnum);
464 if (unlikely(err))
465 goto failed;
466 }
467 list_del(&ent->list);
468 kfree(ent);
469 }
470
471 /* Allocate new segments for recovery */
472 err = nilfs_sufile_alloc(sufile, &segnum[0]);
473 if (unlikely(err))
474 goto failed;
475
476 nilfs->ns_pseg_offset = 0;
477 nilfs->ns_seg_seq = ri->ri_seq + 2;
478 nilfs->ns_nextnum = nilfs->ns_segnum = segnum[0];
479
480 failed:
481 /* No need to recover sufile because it will be destroyed on error */
482 return err;
483}
484
485static int nilfs_recovery_copy_block(struct the_nilfs *nilfs,
486 struct nilfs_recovery_block *rb,
487 struct page *page)
488{
489 struct buffer_head *bh_org;
490 void *kaddr;
491
492 bh_org = __bread(nilfs->ns_bdev, rb->blocknr, nilfs->ns_blocksize);
493 if (unlikely(!bh_org))
494 return -EIO;
495
496 kaddr = kmap_atomic(page);
497 memcpy(kaddr + bh_offset(bh_org), bh_org->b_data, bh_org->b_size);
498 kunmap_atomic(kaddr);
499 brelse(bh_org);
500 return 0;
501}
502
503static int nilfs_recover_dsync_blocks(struct the_nilfs *nilfs,
504 struct super_block *sb,
505 struct nilfs_root *root,
506 struct list_head *head,
507 unsigned long *nr_salvaged_blocks)
508{
509 struct inode *inode;
510 struct nilfs_recovery_block *rb, *n;
511 unsigned blocksize = nilfs->ns_blocksize;
512 struct page *page;
513 loff_t pos;
514 int err = 0, err2 = 0;
515
516 list_for_each_entry_safe(rb, n, head, list) {
517 inode = nilfs_iget(sb, root, rb->ino);
518 if (IS_ERR(inode)) {
519 err = PTR_ERR(inode);
520 inode = NULL;
521 goto failed_inode;
522 }
523
524 pos = rb->blkoff << inode->i_blkbits;
525 err = block_write_begin(inode->i_mapping, pos, blocksize,
526 0, &page, nilfs_get_block);
527 if (unlikely(err)) {
528 loff_t isize = inode->i_size;
529 if (pos + blocksize > isize)
530 vmtruncate(inode, isize);
531 goto failed_inode;
532 }
533
534 err = nilfs_recovery_copy_block(nilfs, rb, page);
535 if (unlikely(err))
536 goto failed_page;
537
538 err = nilfs_set_file_dirty(inode, 1);
539 if (unlikely(err))
540 goto failed_page;
541
542 block_write_end(NULL, inode->i_mapping, pos, blocksize,
543 blocksize, page, NULL);
544
545 unlock_page(page);
546 page_cache_release(page);
547
548 (*nr_salvaged_blocks)++;
549 goto next;
550
551 failed_page:
552 unlock_page(page);
553 page_cache_release(page);
554
555 failed_inode:
556 printk(KERN_WARNING
557 "NILFS warning: error recovering data block "
558 "(err=%d, ino=%lu, block-offset=%llu)\n",
559 err, (unsigned long)rb->ino,
560 (unsigned long long)rb->blkoff);
561 if (!err2)
562 err2 = err;
563 next:
564 iput(inode); /* iput(NULL) is just ignored */
565 list_del_init(&rb->list);
566 kfree(rb);
567 }
568 return err2;
569}
570
571/**
572 * nilfs_do_roll_forward - salvage logical segments newer than the latest
573 * checkpoint
574 * @nilfs: nilfs object
575 * @sb: super block instance
576 * @ri: pointer to a nilfs_recovery_info
577 */
578static int nilfs_do_roll_forward(struct the_nilfs *nilfs,
579 struct super_block *sb,
580 struct nilfs_root *root,
581 struct nilfs_recovery_info *ri)
582{
583 struct buffer_head *bh_sum = NULL;
584 struct nilfs_segment_summary *sum;
585 sector_t pseg_start;
586 sector_t seg_start, seg_end; /* Starting/ending DBN of full segment */
587 unsigned long nsalvaged_blocks = 0;
588 unsigned int flags;
589 u64 seg_seq;
590 __u64 segnum, nextnum = 0;
591 int empty_seg = 0;
592 int err = 0, ret;
593 LIST_HEAD(dsync_blocks); /* list of data blocks to be recovered */
594 enum {
595 RF_INIT_ST,
596 RF_DSYNC_ST, /* scanning data-sync segments */
597 };
598 int state = RF_INIT_ST;
599
600 pseg_start = ri->ri_lsegs_start;
601 seg_seq = ri->ri_lsegs_start_seq;
602 segnum = nilfs_get_segnum_of_block(nilfs, pseg_start);
603 nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end);
604
605 while (segnum != ri->ri_segnum || pseg_start <= ri->ri_pseg_start) {
606 brelse(bh_sum);
607 bh_sum = nilfs_read_log_header(nilfs, pseg_start, &sum);
608 if (!bh_sum) {
609 err = -EIO;
610 goto failed;
611 }
612
613 ret = nilfs_validate_log(nilfs, seg_seq, bh_sum, sum);
614 if (ret) {
615 if (ret == NILFS_SEG_FAIL_IO) {
616 err = -EIO;
617 goto failed;
618 }
619 goto strayed;
620 }
621
622 flags = le16_to_cpu(sum->ss_flags);
623 if (flags & NILFS_SS_SR)
624 goto confused;
625
626 /* Found a valid partial segment; do recovery actions */
627 nextnum = nilfs_get_segnum_of_block(nilfs,
628 le64_to_cpu(sum->ss_next));
629 empty_seg = 0;
630 nilfs->ns_ctime = le64_to_cpu(sum->ss_create);
631 if (!(flags & NILFS_SS_GC))
632 nilfs->ns_nongc_ctime = nilfs->ns_ctime;
633
634 switch (state) {
635 case RF_INIT_ST:
636 if (!(flags & NILFS_SS_LOGBGN) ||
637 !(flags & NILFS_SS_SYNDT))
638 goto try_next_pseg;
639 state = RF_DSYNC_ST;
640 /* Fall through */
641 case RF_DSYNC_ST:
642 if (!(flags & NILFS_SS_SYNDT))
643 goto confused;
644
645 err = nilfs_scan_dsync_log(nilfs, pseg_start, sum,
646 &dsync_blocks);
647 if (unlikely(err))
648 goto failed;
649 if (flags & NILFS_SS_LOGEND) {
650 err = nilfs_recover_dsync_blocks(
651 nilfs, sb, root, &dsync_blocks,
652 &nsalvaged_blocks);
653 if (unlikely(err))
654 goto failed;
655 state = RF_INIT_ST;
656 }
657 break; /* Fall through to try_next_pseg */
658 }
659
660 try_next_pseg:
661 if (pseg_start == ri->ri_lsegs_end)
662 break;
663 pseg_start += le32_to_cpu(sum->ss_nblocks);
664 if (pseg_start < seg_end)
665 continue;
666 goto feed_segment;
667
668 strayed:
669 if (pseg_start == ri->ri_lsegs_end)
670 break;
671
672 feed_segment:
673 /* Looking to the next full segment */
674 if (empty_seg++)
675 break;
676 seg_seq++;
677 segnum = nextnum;
678 nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end);
679 pseg_start = seg_start;
680 }
681
682 if (nsalvaged_blocks) {
683 printk(KERN_INFO "NILFS (device %s): salvaged %lu blocks\n",
684 sb->s_id, nsalvaged_blocks);
685 ri->ri_need_recovery = NILFS_RECOVERY_ROLLFORWARD_DONE;
686 }
687 out:
688 brelse(bh_sum);
689 dispose_recovery_list(&dsync_blocks);
690 return err;
691
692 confused:
693 err = -EINVAL;
694 failed:
695 printk(KERN_ERR
696 "NILFS (device %s): Error roll-forwarding "
697 "(err=%d, pseg block=%llu). ",
698 sb->s_id, err, (unsigned long long)pseg_start);
699 goto out;
700}
701
702static void nilfs_finish_roll_forward(struct the_nilfs *nilfs,
703 struct nilfs_recovery_info *ri)
704{
705 struct buffer_head *bh;
706 int err;
707
708 if (nilfs_get_segnum_of_block(nilfs, ri->ri_lsegs_start) !=
709 nilfs_get_segnum_of_block(nilfs, ri->ri_super_root))
710 return;
711
712 bh = __getblk(nilfs->ns_bdev, ri->ri_lsegs_start, nilfs->ns_blocksize);
713 BUG_ON(!bh);
714 memset(bh->b_data, 0, bh->b_size);
715 set_buffer_dirty(bh);
716 err = sync_dirty_buffer(bh);
717 if (unlikely(err))
718 printk(KERN_WARNING
719 "NILFS warning: buffer sync write failed during "
720 "post-cleaning of recovery.\n");
721 brelse(bh);
722}
723
724/**
725 * nilfs_salvage_orphan_logs - salvage logs written after the latest checkpoint
726 * @nilfs: nilfs object
727 * @sb: super block instance
728 * @ri: pointer to a nilfs_recovery_info struct to store search results.
729 *
730 * Return Value: On success, 0 is returned. On error, one of the following
731 * negative error code is returned.
732 *
733 * %-EINVAL - Inconsistent filesystem state.
734 *
735 * %-EIO - I/O error
736 *
737 * %-ENOSPC - No space left on device (only in a panic state).
738 *
739 * %-ERESTARTSYS - Interrupted.
740 *
741 * %-ENOMEM - Insufficient memory available.
742 */
743int nilfs_salvage_orphan_logs(struct the_nilfs *nilfs,
744 struct super_block *sb,
745 struct nilfs_recovery_info *ri)
746{
747 struct nilfs_root *root;
748 int err;
749
750 if (ri->ri_lsegs_start == 0 || ri->ri_lsegs_end == 0)
751 return 0;
752
753 err = nilfs_attach_checkpoint(sb, ri->ri_cno, true, &root);
754 if (unlikely(err)) {
755 printk(KERN_ERR
756 "NILFS: error loading the latest checkpoint.\n");
757 return err;
758 }
759
760 err = nilfs_do_roll_forward(nilfs, sb, root, ri);
761 if (unlikely(err))
762 goto failed;
763
764 if (ri->ri_need_recovery == NILFS_RECOVERY_ROLLFORWARD_DONE) {
765 err = nilfs_prepare_segment_for_recovery(nilfs, sb, ri);
766 if (unlikely(err)) {
767 printk(KERN_ERR "NILFS: Error preparing segments for "
768 "recovery.\n");
769 goto failed;
770 }
771
772 err = nilfs_attach_log_writer(sb, root);
773 if (unlikely(err))
774 goto failed;
775
776 set_nilfs_discontinued(nilfs);
777 err = nilfs_construct_segment(sb);
778 nilfs_detach_log_writer(sb);
779
780 if (unlikely(err)) {
781 printk(KERN_ERR "NILFS: Oops! recovery failed. "
782 "(err=%d)\n", err);
783 goto failed;
784 }
785
786 nilfs_finish_roll_forward(nilfs, ri);
787 }
788
789 failed:
790 nilfs_put_root(root);
791 return err;
792}
793
794/**
795 * nilfs_search_super_root - search the latest valid super root
796 * @nilfs: the_nilfs
797 * @ri: pointer to a nilfs_recovery_info struct to store search results.
798 *
799 * nilfs_search_super_root() looks for the latest super-root from a partial
800 * segment pointed by the superblock. It sets up struct the_nilfs through
801 * this search. It fills nilfs_recovery_info (ri) required for recovery.
802 *
803 * Return Value: On success, 0 is returned. On error, one of the following
804 * negative error code is returned.
805 *
806 * %-EINVAL - No valid segment found
807 *
808 * %-EIO - I/O error
809 *
810 * %-ENOMEM - Insufficient memory available.
811 */
812int nilfs_search_super_root(struct the_nilfs *nilfs,
813 struct nilfs_recovery_info *ri)
814{
815 struct buffer_head *bh_sum = NULL;
816 struct nilfs_segment_summary *sum;
817 sector_t pseg_start, pseg_end, sr_pseg_start = 0;
818 sector_t seg_start, seg_end; /* range of full segment (block number) */
819 sector_t b, end;
820 unsigned long nblocks;
821 unsigned int flags;
822 u64 seg_seq;
823 __u64 segnum, nextnum = 0;
824 __u64 cno;
825 LIST_HEAD(segments);
826 int empty_seg = 0, scan_newer = 0;
827 int ret;
828
829 pseg_start = nilfs->ns_last_pseg;
830 seg_seq = nilfs->ns_last_seq;
831 cno = nilfs->ns_last_cno;
832 segnum = nilfs_get_segnum_of_block(nilfs, pseg_start);
833
834 /* Calculate range of segment */
835 nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end);
836
837 /* Read ahead segment */
838 b = seg_start;
839 while (b <= seg_end)
840 __breadahead(nilfs->ns_bdev, b++, nilfs->ns_blocksize);
841
842 for (;;) {
843 brelse(bh_sum);
844 ret = NILFS_SEG_FAIL_IO;
845 bh_sum = nilfs_read_log_header(nilfs, pseg_start, &sum);
846 if (!bh_sum)
847 goto failed;
848
849 ret = nilfs_validate_log(nilfs, seg_seq, bh_sum, sum);
850 if (ret) {
851 if (ret == NILFS_SEG_FAIL_IO)
852 goto failed;
853 goto strayed;
854 }
855
856 nblocks = le32_to_cpu(sum->ss_nblocks);
857 pseg_end = pseg_start + nblocks - 1;
858 if (unlikely(pseg_end > seg_end)) {
859 ret = NILFS_SEG_FAIL_CONSISTENCY;
860 goto strayed;
861 }
862
863 /* A valid partial segment */
864 ri->ri_pseg_start = pseg_start;
865 ri->ri_seq = seg_seq;
866 ri->ri_segnum = segnum;
867 nextnum = nilfs_get_segnum_of_block(nilfs,
868 le64_to_cpu(sum->ss_next));
869 ri->ri_nextnum = nextnum;
870 empty_seg = 0;
871
872 flags = le16_to_cpu(sum->ss_flags);
873 if (!(flags & NILFS_SS_SR) && !scan_newer) {
874 /* This will never happen because a superblock
875 (last_segment) always points to a pseg
876 having a super root. */
877 ret = NILFS_SEG_FAIL_CONSISTENCY;
878 goto failed;
879 }
880
881 if (pseg_start == seg_start) {
882 nilfs_get_segment_range(nilfs, nextnum, &b, &end);
883 while (b <= end)
884 __breadahead(nilfs->ns_bdev, b++,
885 nilfs->ns_blocksize);
886 }
887 if (!(flags & NILFS_SS_SR)) {
888 if (!ri->ri_lsegs_start && (flags & NILFS_SS_LOGBGN)) {
889 ri->ri_lsegs_start = pseg_start;
890 ri->ri_lsegs_start_seq = seg_seq;
891 }
892 if (flags & NILFS_SS_LOGEND)
893 ri->ri_lsegs_end = pseg_start;
894 goto try_next_pseg;
895 }
896
897 /* A valid super root was found. */
898 ri->ri_cno = cno++;
899 ri->ri_super_root = pseg_end;
900 ri->ri_lsegs_start = ri->ri_lsegs_end = 0;
901
902 nilfs_dispose_segment_list(&segments);
903 sr_pseg_start = pseg_start;
904 nilfs->ns_pseg_offset = pseg_start + nblocks - seg_start;
905 nilfs->ns_seg_seq = seg_seq;
906 nilfs->ns_segnum = segnum;
907 nilfs->ns_cno = cno; /* nilfs->ns_cno = ri->ri_cno + 1 */
908 nilfs->ns_ctime = le64_to_cpu(sum->ss_create);
909 nilfs->ns_nextnum = nextnum;
910
911 if (scan_newer)
912 ri->ri_need_recovery = NILFS_RECOVERY_SR_UPDATED;
913 else {
914 if (nilfs->ns_mount_state & NILFS_VALID_FS)
915 goto super_root_found;
916 scan_newer = 1;
917 }
918
919 try_next_pseg:
920 /* Standing on a course, or met an inconsistent state */
921 pseg_start += nblocks;
922 if (pseg_start < seg_end)
923 continue;
924 goto feed_segment;
925
926 strayed:
927 /* Off the trail */
928 if (!scan_newer)
929 /*
930 * This can happen if a checkpoint was written without
931 * barriers, or as a result of an I/O failure.
932 */
933 goto failed;
934
935 feed_segment:
936 /* Looking to the next full segment */
937 if (empty_seg++)
938 goto super_root_found; /* found a valid super root */
939
940 ret = nilfs_segment_list_add(&segments, segnum);
941 if (unlikely(ret))
942 goto failed;
943
944 seg_seq++;
945 segnum = nextnum;
946 nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end);
947 pseg_start = seg_start;
948 }
949
950 super_root_found:
951 /* Updating pointers relating to the latest checkpoint */
952 brelse(bh_sum);
953 list_splice_tail(&segments, &ri->ri_used_segments);
954 nilfs->ns_last_pseg = sr_pseg_start;
955 nilfs->ns_last_seq = nilfs->ns_seg_seq;
956 nilfs->ns_last_cno = ri->ri_cno;
957 return 0;
958
959 failed:
960 brelse(bh_sum);
961 nilfs_dispose_segment_list(&segments);
962 return (ret < 0) ? ret : nilfs_warn_segment_error(ret);
963}