WIP FPC-III support
[linux/fpc-iii.git] / fs / nilfs2 / recovery.c
blob2217f904a7cfb5230b2e66b11660a0dbb1d20d24
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * recovery.c - NILFS recovery logic
5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
7 * Written by Ryusuke Konishi.
8 */
10 #include <linux/buffer_head.h>
11 #include <linux/blkdev.h>
12 #include <linux/swap.h>
13 #include <linux/slab.h>
14 #include <linux/crc32.h>
15 #include "nilfs.h"
16 #include "segment.h"
17 #include "sufile.h"
18 #include "page.h"
19 #include "segbuf.h"
22 * Segment check result
24 enum {
25 NILFS_SEG_VALID,
26 NILFS_SEG_NO_SUPER_ROOT,
27 NILFS_SEG_FAIL_IO,
28 NILFS_SEG_FAIL_MAGIC,
29 NILFS_SEG_FAIL_SEQ,
30 NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT,
31 NILFS_SEG_FAIL_CHECKSUM_FULL,
32 NILFS_SEG_FAIL_CONSISTENCY,
35 /* work structure for recovery */
36 struct nilfs_recovery_block {
37 ino_t ino; /*
38 * Inode number of the file that this block
39 * belongs to
41 sector_t blocknr; /* block number */
42 __u64 vblocknr; /* virtual block number */
43 unsigned long blkoff; /* File offset of the data block (per block) */
44 struct list_head list;
48 static int nilfs_warn_segment_error(struct super_block *sb, int err)
50 const char *msg = NULL;
52 switch (err) {
53 case NILFS_SEG_FAIL_IO:
54 nilfs_err(sb, "I/O error reading segment");
55 return -EIO;
56 case NILFS_SEG_FAIL_MAGIC:
57 msg = "Magic number mismatch";
58 break;
59 case NILFS_SEG_FAIL_SEQ:
60 msg = "Sequence number mismatch";
61 break;
62 case NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT:
63 msg = "Checksum error in super root";
64 break;
65 case NILFS_SEG_FAIL_CHECKSUM_FULL:
66 msg = "Checksum error in segment payload";
67 break;
68 case NILFS_SEG_FAIL_CONSISTENCY:
69 msg = "Inconsistency found";
70 break;
71 case NILFS_SEG_NO_SUPER_ROOT:
72 msg = "No super root in the last segment";
73 break;
74 default:
75 nilfs_err(sb, "unrecognized segment error %d", err);
76 return -EINVAL;
78 nilfs_warn(sb, "invalid segment: %s", msg);
79 return -EINVAL;
82 /**
83 * nilfs_compute_checksum - compute checksum of blocks continuously
84 * @nilfs: nilfs object
85 * @bhs: buffer head of start block
86 * @sum: place to store result
87 * @offset: offset bytes in the first block
88 * @check_bytes: number of bytes to be checked
89 * @start: DBN of start block
90 * @nblock: number of blocks to be checked
92 static int nilfs_compute_checksum(struct the_nilfs *nilfs,
93 struct buffer_head *bhs, u32 *sum,
94 unsigned long offset, u64 check_bytes,
95 sector_t start, unsigned long nblock)
97 unsigned int blocksize = nilfs->ns_blocksize;
98 unsigned long size;
99 u32 crc;
101 BUG_ON(offset >= blocksize);
102 check_bytes -= offset;
103 size = min_t(u64, check_bytes, blocksize - offset);
104 crc = crc32_le(nilfs->ns_crc_seed,
105 (unsigned char *)bhs->b_data + offset, size);
106 if (--nblock > 0) {
107 do {
108 struct buffer_head *bh;
110 bh = __bread(nilfs->ns_bdev, ++start, blocksize);
111 if (!bh)
112 return -EIO;
113 check_bytes -= size;
114 size = min_t(u64, check_bytes, blocksize);
115 crc = crc32_le(crc, bh->b_data, size);
116 brelse(bh);
117 } while (--nblock > 0);
119 *sum = crc;
120 return 0;
124 * nilfs_read_super_root_block - read super root block
125 * @nilfs: nilfs object
126 * @sr_block: disk block number of the super root block
127 * @pbh: address of a buffer_head pointer to return super root buffer
128 * @check: CRC check flag
130 int nilfs_read_super_root_block(struct the_nilfs *nilfs, sector_t sr_block,
131 struct buffer_head **pbh, int check)
133 struct buffer_head *bh_sr;
134 struct nilfs_super_root *sr;
135 u32 crc;
136 int ret;
138 *pbh = NULL;
139 bh_sr = __bread(nilfs->ns_bdev, sr_block, nilfs->ns_blocksize);
140 if (unlikely(!bh_sr)) {
141 ret = NILFS_SEG_FAIL_IO;
142 goto failed;
145 sr = (struct nilfs_super_root *)bh_sr->b_data;
146 if (check) {
147 unsigned int bytes = le16_to_cpu(sr->sr_bytes);
149 if (bytes == 0 || bytes > nilfs->ns_blocksize) {
150 ret = NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT;
151 goto failed_bh;
153 if (nilfs_compute_checksum(
154 nilfs, bh_sr, &crc, sizeof(sr->sr_sum), bytes,
155 sr_block, 1)) {
156 ret = NILFS_SEG_FAIL_IO;
157 goto failed_bh;
159 if (crc != le32_to_cpu(sr->sr_sum)) {
160 ret = NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT;
161 goto failed_bh;
164 *pbh = bh_sr;
165 return 0;
167 failed_bh:
168 brelse(bh_sr);
170 failed:
171 return nilfs_warn_segment_error(nilfs->ns_sb, ret);
175 * nilfs_read_log_header - read summary header of the specified log
176 * @nilfs: nilfs object
177 * @start_blocknr: start block number of the log
178 * @sum: pointer to return segment summary structure
180 static struct buffer_head *
181 nilfs_read_log_header(struct the_nilfs *nilfs, sector_t start_blocknr,
182 struct nilfs_segment_summary **sum)
184 struct buffer_head *bh_sum;
186 bh_sum = __bread(nilfs->ns_bdev, start_blocknr, nilfs->ns_blocksize);
187 if (bh_sum)
188 *sum = (struct nilfs_segment_summary *)bh_sum->b_data;
189 return bh_sum;
193 * nilfs_validate_log - verify consistency of log
194 * @nilfs: nilfs object
195 * @seg_seq: sequence number of segment
196 * @bh_sum: buffer head of summary block
197 * @sum: segment summary struct
199 static int nilfs_validate_log(struct the_nilfs *nilfs, u64 seg_seq,
200 struct buffer_head *bh_sum,
201 struct nilfs_segment_summary *sum)
203 unsigned long nblock;
204 u32 crc;
205 int ret;
207 ret = NILFS_SEG_FAIL_MAGIC;
208 if (le32_to_cpu(sum->ss_magic) != NILFS_SEGSUM_MAGIC)
209 goto out;
211 ret = NILFS_SEG_FAIL_SEQ;
212 if (le64_to_cpu(sum->ss_seq) != seg_seq)
213 goto out;
215 nblock = le32_to_cpu(sum->ss_nblocks);
216 ret = NILFS_SEG_FAIL_CONSISTENCY;
217 if (unlikely(nblock == 0 || nblock > nilfs->ns_blocks_per_segment))
218 /* This limits the number of blocks read in the CRC check */
219 goto out;
221 ret = NILFS_SEG_FAIL_IO;
222 if (nilfs_compute_checksum(nilfs, bh_sum, &crc, sizeof(sum->ss_datasum),
223 ((u64)nblock << nilfs->ns_blocksize_bits),
224 bh_sum->b_blocknr, nblock))
225 goto out;
227 ret = NILFS_SEG_FAIL_CHECKSUM_FULL;
228 if (crc != le32_to_cpu(sum->ss_datasum))
229 goto out;
230 ret = 0;
231 out:
232 return ret;
236 * nilfs_read_summary_info - read an item on summary blocks of a log
237 * @nilfs: nilfs object
238 * @pbh: the current buffer head on summary blocks [in, out]
239 * @offset: the current byte offset on summary blocks [in, out]
240 * @bytes: byte size of the item to be read
242 static void *nilfs_read_summary_info(struct the_nilfs *nilfs,
243 struct buffer_head **pbh,
244 unsigned int *offset, unsigned int bytes)
246 void *ptr;
247 sector_t blocknr;
249 BUG_ON((*pbh)->b_size < *offset);
250 if (bytes > (*pbh)->b_size - *offset) {
251 blocknr = (*pbh)->b_blocknr;
252 brelse(*pbh);
253 *pbh = __bread(nilfs->ns_bdev, blocknr + 1,
254 nilfs->ns_blocksize);
255 if (unlikely(!*pbh))
256 return NULL;
257 *offset = 0;
259 ptr = (*pbh)->b_data + *offset;
260 *offset += bytes;
261 return ptr;
265 * nilfs_skip_summary_info - skip items on summary blocks of a log
266 * @nilfs: nilfs object
267 * @pbh: the current buffer head on summary blocks [in, out]
268 * @offset: the current byte offset on summary blocks [in, out]
269 * @bytes: byte size of the item to be skipped
270 * @count: number of items to be skipped
272 static void nilfs_skip_summary_info(struct the_nilfs *nilfs,
273 struct buffer_head **pbh,
274 unsigned int *offset, unsigned int bytes,
275 unsigned long count)
277 unsigned int rest_item_in_current_block
278 = ((*pbh)->b_size - *offset) / bytes;
280 if (count <= rest_item_in_current_block) {
281 *offset += bytes * count;
282 } else {
283 sector_t blocknr = (*pbh)->b_blocknr;
284 unsigned int nitem_per_block = (*pbh)->b_size / bytes;
285 unsigned int bcnt;
287 count -= rest_item_in_current_block;
288 bcnt = DIV_ROUND_UP(count, nitem_per_block);
289 *offset = bytes * (count - (bcnt - 1) * nitem_per_block);
291 brelse(*pbh);
292 *pbh = __bread(nilfs->ns_bdev, blocknr + bcnt,
293 nilfs->ns_blocksize);
298 * nilfs_scan_dsync_log - get block information of a log written for data sync
299 * @nilfs: nilfs object
300 * @start_blocknr: start block number of the log
301 * @sum: log summary information
302 * @head: list head to add nilfs_recovery_block struct
304 static int nilfs_scan_dsync_log(struct the_nilfs *nilfs, sector_t start_blocknr,
305 struct nilfs_segment_summary *sum,
306 struct list_head *head)
308 struct buffer_head *bh;
309 unsigned int offset;
310 u32 nfinfo, sumbytes;
311 sector_t blocknr;
312 ino_t ino;
313 int err = -EIO;
315 nfinfo = le32_to_cpu(sum->ss_nfinfo);
316 if (!nfinfo)
317 return 0;
319 sumbytes = le32_to_cpu(sum->ss_sumbytes);
320 blocknr = start_blocknr + DIV_ROUND_UP(sumbytes, nilfs->ns_blocksize);
321 bh = __bread(nilfs->ns_bdev, start_blocknr, nilfs->ns_blocksize);
322 if (unlikely(!bh))
323 goto out;
325 offset = le16_to_cpu(sum->ss_bytes);
326 for (;;) {
327 unsigned long nblocks, ndatablk, nnodeblk;
328 struct nilfs_finfo *finfo;
330 finfo = nilfs_read_summary_info(nilfs, &bh, &offset,
331 sizeof(*finfo));
332 if (unlikely(!finfo))
333 goto out;
335 ino = le64_to_cpu(finfo->fi_ino);
336 nblocks = le32_to_cpu(finfo->fi_nblocks);
337 ndatablk = le32_to_cpu(finfo->fi_ndatablk);
338 nnodeblk = nblocks - ndatablk;
340 while (ndatablk-- > 0) {
341 struct nilfs_recovery_block *rb;
342 struct nilfs_binfo_v *binfo;
344 binfo = nilfs_read_summary_info(nilfs, &bh, &offset,
345 sizeof(*binfo));
346 if (unlikely(!binfo))
347 goto out;
349 rb = kmalloc(sizeof(*rb), GFP_NOFS);
350 if (unlikely(!rb)) {
351 err = -ENOMEM;
352 goto out;
354 rb->ino = ino;
355 rb->blocknr = blocknr++;
356 rb->vblocknr = le64_to_cpu(binfo->bi_vblocknr);
357 rb->blkoff = le64_to_cpu(binfo->bi_blkoff);
358 /* INIT_LIST_HEAD(&rb->list); */
359 list_add_tail(&rb->list, head);
361 if (--nfinfo == 0)
362 break;
363 blocknr += nnodeblk; /* always 0 for data sync logs */
364 nilfs_skip_summary_info(nilfs, &bh, &offset, sizeof(__le64),
365 nnodeblk);
366 if (unlikely(!bh))
367 goto out;
369 err = 0;
370 out:
371 brelse(bh); /* brelse(NULL) is just ignored */
372 return err;
375 static void dispose_recovery_list(struct list_head *head)
377 while (!list_empty(head)) {
378 struct nilfs_recovery_block *rb;
380 rb = list_first_entry(head, struct nilfs_recovery_block, list);
381 list_del(&rb->list);
382 kfree(rb);
386 struct nilfs_segment_entry {
387 struct list_head list;
388 __u64 segnum;
391 static int nilfs_segment_list_add(struct list_head *head, __u64 segnum)
393 struct nilfs_segment_entry *ent = kmalloc(sizeof(*ent), GFP_NOFS);
395 if (unlikely(!ent))
396 return -ENOMEM;
398 ent->segnum = segnum;
399 INIT_LIST_HEAD(&ent->list);
400 list_add_tail(&ent->list, head);
401 return 0;
404 void nilfs_dispose_segment_list(struct list_head *head)
406 while (!list_empty(head)) {
407 struct nilfs_segment_entry *ent;
409 ent = list_first_entry(head, struct nilfs_segment_entry, list);
410 list_del(&ent->list);
411 kfree(ent);
415 static int nilfs_prepare_segment_for_recovery(struct the_nilfs *nilfs,
416 struct super_block *sb,
417 struct nilfs_recovery_info *ri)
419 struct list_head *head = &ri->ri_used_segments;
420 struct nilfs_segment_entry *ent, *n;
421 struct inode *sufile = nilfs->ns_sufile;
422 __u64 segnum[4];
423 int err;
424 int i;
426 segnum[0] = nilfs->ns_segnum;
427 segnum[1] = nilfs->ns_nextnum;
428 segnum[2] = ri->ri_segnum;
429 segnum[3] = ri->ri_nextnum;
432 * Releasing the next segment of the latest super root.
433 * The next segment is invalidated by this recovery.
435 err = nilfs_sufile_free(sufile, segnum[1]);
436 if (unlikely(err))
437 goto failed;
439 for (i = 1; i < 4; i++) {
440 err = nilfs_segment_list_add(head, segnum[i]);
441 if (unlikely(err))
442 goto failed;
446 * Collecting segments written after the latest super root.
447 * These are marked dirty to avoid being reallocated in the next write.
449 list_for_each_entry_safe(ent, n, head, list) {
450 if (ent->segnum != segnum[0]) {
451 err = nilfs_sufile_scrap(sufile, ent->segnum);
452 if (unlikely(err))
453 goto failed;
455 list_del(&ent->list);
456 kfree(ent);
459 /* Allocate new segments for recovery */
460 err = nilfs_sufile_alloc(sufile, &segnum[0]);
461 if (unlikely(err))
462 goto failed;
464 nilfs->ns_pseg_offset = 0;
465 nilfs->ns_seg_seq = ri->ri_seq + 2;
466 nilfs->ns_nextnum = nilfs->ns_segnum = segnum[0];
468 failed:
469 /* No need to recover sufile because it will be destroyed on error */
470 return err;
473 static int nilfs_recovery_copy_block(struct the_nilfs *nilfs,
474 struct nilfs_recovery_block *rb,
475 struct page *page)
477 struct buffer_head *bh_org;
478 void *kaddr;
480 bh_org = __bread(nilfs->ns_bdev, rb->blocknr, nilfs->ns_blocksize);
481 if (unlikely(!bh_org))
482 return -EIO;
484 kaddr = kmap_atomic(page);
485 memcpy(kaddr + bh_offset(bh_org), bh_org->b_data, bh_org->b_size);
486 kunmap_atomic(kaddr);
487 brelse(bh_org);
488 return 0;
491 static int nilfs_recover_dsync_blocks(struct the_nilfs *nilfs,
492 struct super_block *sb,
493 struct nilfs_root *root,
494 struct list_head *head,
495 unsigned long *nr_salvaged_blocks)
497 struct inode *inode;
498 struct nilfs_recovery_block *rb, *n;
499 unsigned int blocksize = nilfs->ns_blocksize;
500 struct page *page;
501 loff_t pos;
502 int err = 0, err2 = 0;
504 list_for_each_entry_safe(rb, n, head, list) {
505 inode = nilfs_iget(sb, root, rb->ino);
506 if (IS_ERR(inode)) {
507 err = PTR_ERR(inode);
508 inode = NULL;
509 goto failed_inode;
512 pos = rb->blkoff << inode->i_blkbits;
513 err = block_write_begin(inode->i_mapping, pos, blocksize,
514 0, &page, nilfs_get_block);
515 if (unlikely(err)) {
516 loff_t isize = inode->i_size;
518 if (pos + blocksize > isize)
519 nilfs_write_failed(inode->i_mapping,
520 pos + blocksize);
521 goto failed_inode;
524 err = nilfs_recovery_copy_block(nilfs, rb, page);
525 if (unlikely(err))
526 goto failed_page;
528 err = nilfs_set_file_dirty(inode, 1);
529 if (unlikely(err))
530 goto failed_page;
532 block_write_end(NULL, inode->i_mapping, pos, blocksize,
533 blocksize, page, NULL);
535 unlock_page(page);
536 put_page(page);
538 (*nr_salvaged_blocks)++;
539 goto next;
541 failed_page:
542 unlock_page(page);
543 put_page(page);
545 failed_inode:
546 nilfs_warn(sb,
547 "error %d recovering data block (ino=%lu, block-offset=%llu)",
548 err, (unsigned long)rb->ino,
549 (unsigned long long)rb->blkoff);
550 if (!err2)
551 err2 = err;
552 next:
553 iput(inode); /* iput(NULL) is just ignored */
554 list_del_init(&rb->list);
555 kfree(rb);
557 return err2;
561 * nilfs_do_roll_forward - salvage logical segments newer than the latest
562 * checkpoint
563 * @nilfs: nilfs object
564 * @sb: super block instance
565 * @ri: pointer to a nilfs_recovery_info
567 static int nilfs_do_roll_forward(struct the_nilfs *nilfs,
568 struct super_block *sb,
569 struct nilfs_root *root,
570 struct nilfs_recovery_info *ri)
572 struct buffer_head *bh_sum = NULL;
573 struct nilfs_segment_summary *sum = NULL;
574 sector_t pseg_start;
575 sector_t seg_start, seg_end; /* Starting/ending DBN of full segment */
576 unsigned long nsalvaged_blocks = 0;
577 unsigned int flags;
578 u64 seg_seq;
579 __u64 segnum, nextnum = 0;
580 int empty_seg = 0;
581 int err = 0, ret;
582 LIST_HEAD(dsync_blocks); /* list of data blocks to be recovered */
583 enum {
584 RF_INIT_ST,
585 RF_DSYNC_ST, /* scanning data-sync segments */
587 int state = RF_INIT_ST;
589 pseg_start = ri->ri_lsegs_start;
590 seg_seq = ri->ri_lsegs_start_seq;
591 segnum = nilfs_get_segnum_of_block(nilfs, pseg_start);
592 nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end);
594 while (segnum != ri->ri_segnum || pseg_start <= ri->ri_pseg_start) {
595 brelse(bh_sum);
596 bh_sum = nilfs_read_log_header(nilfs, pseg_start, &sum);
597 if (!bh_sum) {
598 err = -EIO;
599 goto failed;
602 ret = nilfs_validate_log(nilfs, seg_seq, bh_sum, sum);
603 if (ret) {
604 if (ret == NILFS_SEG_FAIL_IO) {
605 err = -EIO;
606 goto failed;
608 goto strayed;
611 flags = le16_to_cpu(sum->ss_flags);
612 if (flags & NILFS_SS_SR)
613 goto confused;
615 /* Found a valid partial segment; do recovery actions */
616 nextnum = nilfs_get_segnum_of_block(nilfs,
617 le64_to_cpu(sum->ss_next));
618 empty_seg = 0;
619 nilfs->ns_ctime = le64_to_cpu(sum->ss_create);
620 if (!(flags & NILFS_SS_GC))
621 nilfs->ns_nongc_ctime = nilfs->ns_ctime;
623 switch (state) {
624 case RF_INIT_ST:
625 if (!(flags & NILFS_SS_LOGBGN) ||
626 !(flags & NILFS_SS_SYNDT))
627 goto try_next_pseg;
628 state = RF_DSYNC_ST;
629 fallthrough;
630 case RF_DSYNC_ST:
631 if (!(flags & NILFS_SS_SYNDT))
632 goto confused;
634 err = nilfs_scan_dsync_log(nilfs, pseg_start, sum,
635 &dsync_blocks);
636 if (unlikely(err))
637 goto failed;
638 if (flags & NILFS_SS_LOGEND) {
639 err = nilfs_recover_dsync_blocks(
640 nilfs, sb, root, &dsync_blocks,
641 &nsalvaged_blocks);
642 if (unlikely(err))
643 goto failed;
644 state = RF_INIT_ST;
646 break; /* Fall through to try_next_pseg */
649 try_next_pseg:
650 if (pseg_start == ri->ri_lsegs_end)
651 break;
652 pseg_start += le32_to_cpu(sum->ss_nblocks);
653 if (pseg_start < seg_end)
654 continue;
655 goto feed_segment;
657 strayed:
658 if (pseg_start == ri->ri_lsegs_end)
659 break;
661 feed_segment:
662 /* Looking to the next full segment */
663 if (empty_seg++)
664 break;
665 seg_seq++;
666 segnum = nextnum;
667 nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end);
668 pseg_start = seg_start;
671 if (nsalvaged_blocks) {
672 nilfs_info(sb, "salvaged %lu blocks", nsalvaged_blocks);
673 ri->ri_need_recovery = NILFS_RECOVERY_ROLLFORWARD_DONE;
675 out:
676 brelse(bh_sum);
677 dispose_recovery_list(&dsync_blocks);
678 return err;
680 confused:
681 err = -EINVAL;
682 failed:
683 nilfs_err(sb,
684 "error %d roll-forwarding partial segment at blocknr = %llu",
685 err, (unsigned long long)pseg_start);
686 goto out;
689 static void nilfs_finish_roll_forward(struct the_nilfs *nilfs,
690 struct nilfs_recovery_info *ri)
692 struct buffer_head *bh;
693 int err;
695 if (nilfs_get_segnum_of_block(nilfs, ri->ri_lsegs_start) !=
696 nilfs_get_segnum_of_block(nilfs, ri->ri_super_root))
697 return;
699 bh = __getblk(nilfs->ns_bdev, ri->ri_lsegs_start, nilfs->ns_blocksize);
700 BUG_ON(!bh);
701 memset(bh->b_data, 0, bh->b_size);
702 set_buffer_dirty(bh);
703 err = sync_dirty_buffer(bh);
704 if (unlikely(err))
705 nilfs_warn(nilfs->ns_sb,
706 "buffer sync write failed during post-cleaning of recovery.");
707 brelse(bh);
711 * nilfs_salvage_orphan_logs - salvage logs written after the latest checkpoint
712 * @nilfs: nilfs object
713 * @sb: super block instance
714 * @ri: pointer to a nilfs_recovery_info struct to store search results.
716 * Return Value: On success, 0 is returned. On error, one of the following
717 * negative error code is returned.
719 * %-EINVAL - Inconsistent filesystem state.
721 * %-EIO - I/O error
723 * %-ENOSPC - No space left on device (only in a panic state).
725 * %-ERESTARTSYS - Interrupted.
727 * %-ENOMEM - Insufficient memory available.
729 int nilfs_salvage_orphan_logs(struct the_nilfs *nilfs,
730 struct super_block *sb,
731 struct nilfs_recovery_info *ri)
733 struct nilfs_root *root;
734 int err;
736 if (ri->ri_lsegs_start == 0 || ri->ri_lsegs_end == 0)
737 return 0;
739 err = nilfs_attach_checkpoint(sb, ri->ri_cno, true, &root);
740 if (unlikely(err)) {
741 nilfs_err(sb, "error %d loading the latest checkpoint", err);
742 return err;
745 err = nilfs_do_roll_forward(nilfs, sb, root, ri);
746 if (unlikely(err))
747 goto failed;
749 if (ri->ri_need_recovery == NILFS_RECOVERY_ROLLFORWARD_DONE) {
750 err = nilfs_prepare_segment_for_recovery(nilfs, sb, ri);
751 if (unlikely(err)) {
752 nilfs_err(sb, "error %d preparing segment for recovery",
753 err);
754 goto failed;
757 err = nilfs_attach_log_writer(sb, root);
758 if (unlikely(err))
759 goto failed;
761 set_nilfs_discontinued(nilfs);
762 err = nilfs_construct_segment(sb);
763 nilfs_detach_log_writer(sb);
765 if (unlikely(err)) {
766 nilfs_err(sb, "error %d writing segment for recovery",
767 err);
768 goto failed;
771 nilfs_finish_roll_forward(nilfs, ri);
774 failed:
775 nilfs_put_root(root);
776 return err;
780 * nilfs_search_super_root - search the latest valid super root
781 * @nilfs: the_nilfs
782 * @ri: pointer to a nilfs_recovery_info struct to store search results.
784 * nilfs_search_super_root() looks for the latest super-root from a partial
785 * segment pointed by the superblock. It sets up struct the_nilfs through
786 * this search. It fills nilfs_recovery_info (ri) required for recovery.
788 * Return Value: On success, 0 is returned. On error, one of the following
789 * negative error code is returned.
791 * %-EINVAL - No valid segment found
793 * %-EIO - I/O error
795 * %-ENOMEM - Insufficient memory available.
797 int nilfs_search_super_root(struct the_nilfs *nilfs,
798 struct nilfs_recovery_info *ri)
800 struct buffer_head *bh_sum = NULL;
801 struct nilfs_segment_summary *sum = NULL;
802 sector_t pseg_start, pseg_end, sr_pseg_start = 0;
803 sector_t seg_start, seg_end; /* range of full segment (block number) */
804 sector_t b, end;
805 unsigned long nblocks;
806 unsigned int flags;
807 u64 seg_seq;
808 __u64 segnum, nextnum = 0;
809 __u64 cno;
810 LIST_HEAD(segments);
811 int empty_seg = 0, scan_newer = 0;
812 int ret;
814 pseg_start = nilfs->ns_last_pseg;
815 seg_seq = nilfs->ns_last_seq;
816 cno = nilfs->ns_last_cno;
817 segnum = nilfs_get_segnum_of_block(nilfs, pseg_start);
819 /* Calculate range of segment */
820 nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end);
822 /* Read ahead segment */
823 b = seg_start;
824 while (b <= seg_end)
825 __breadahead(nilfs->ns_bdev, b++, nilfs->ns_blocksize);
827 for (;;) {
828 brelse(bh_sum);
829 ret = NILFS_SEG_FAIL_IO;
830 bh_sum = nilfs_read_log_header(nilfs, pseg_start, &sum);
831 if (!bh_sum)
832 goto failed;
834 ret = nilfs_validate_log(nilfs, seg_seq, bh_sum, sum);
835 if (ret) {
836 if (ret == NILFS_SEG_FAIL_IO)
837 goto failed;
838 goto strayed;
841 nblocks = le32_to_cpu(sum->ss_nblocks);
842 pseg_end = pseg_start + nblocks - 1;
843 if (unlikely(pseg_end > seg_end)) {
844 ret = NILFS_SEG_FAIL_CONSISTENCY;
845 goto strayed;
848 /* A valid partial segment */
849 ri->ri_pseg_start = pseg_start;
850 ri->ri_seq = seg_seq;
851 ri->ri_segnum = segnum;
852 nextnum = nilfs_get_segnum_of_block(nilfs,
853 le64_to_cpu(sum->ss_next));
854 ri->ri_nextnum = nextnum;
855 empty_seg = 0;
857 flags = le16_to_cpu(sum->ss_flags);
858 if (!(flags & NILFS_SS_SR) && !scan_newer) {
860 * This will never happen because a superblock
861 * (last_segment) always points to a pseg with
862 * a super root.
864 ret = NILFS_SEG_FAIL_CONSISTENCY;
865 goto failed;
868 if (pseg_start == seg_start) {
869 nilfs_get_segment_range(nilfs, nextnum, &b, &end);
870 while (b <= end)
871 __breadahead(nilfs->ns_bdev, b++,
872 nilfs->ns_blocksize);
874 if (!(flags & NILFS_SS_SR)) {
875 if (!ri->ri_lsegs_start && (flags & NILFS_SS_LOGBGN)) {
876 ri->ri_lsegs_start = pseg_start;
877 ri->ri_lsegs_start_seq = seg_seq;
879 if (flags & NILFS_SS_LOGEND)
880 ri->ri_lsegs_end = pseg_start;
881 goto try_next_pseg;
884 /* A valid super root was found. */
885 ri->ri_cno = cno++;
886 ri->ri_super_root = pseg_end;
887 ri->ri_lsegs_start = ri->ri_lsegs_end = 0;
889 nilfs_dispose_segment_list(&segments);
890 sr_pseg_start = pseg_start;
891 nilfs->ns_pseg_offset = pseg_start + nblocks - seg_start;
892 nilfs->ns_seg_seq = seg_seq;
893 nilfs->ns_segnum = segnum;
894 nilfs->ns_cno = cno; /* nilfs->ns_cno = ri->ri_cno + 1 */
895 nilfs->ns_ctime = le64_to_cpu(sum->ss_create);
896 nilfs->ns_nextnum = nextnum;
898 if (scan_newer)
899 ri->ri_need_recovery = NILFS_RECOVERY_SR_UPDATED;
900 else {
901 if (nilfs->ns_mount_state & NILFS_VALID_FS)
902 goto super_root_found;
903 scan_newer = 1;
906 try_next_pseg:
907 /* Standing on a course, or met an inconsistent state */
908 pseg_start += nblocks;
909 if (pseg_start < seg_end)
910 continue;
911 goto feed_segment;
913 strayed:
914 /* Off the trail */
915 if (!scan_newer)
917 * This can happen if a checkpoint was written without
918 * barriers, or as a result of an I/O failure.
920 goto failed;
922 feed_segment:
923 /* Looking to the next full segment */
924 if (empty_seg++)
925 goto super_root_found; /* found a valid super root */
927 ret = nilfs_segment_list_add(&segments, segnum);
928 if (unlikely(ret))
929 goto failed;
931 seg_seq++;
932 segnum = nextnum;
933 nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end);
934 pseg_start = seg_start;
937 super_root_found:
938 /* Updating pointers relating to the latest checkpoint */
939 brelse(bh_sum);
940 list_splice_tail(&segments, &ri->ri_used_segments);
941 nilfs->ns_last_pseg = sr_pseg_start;
942 nilfs->ns_last_seq = nilfs->ns_seg_seq;
943 nilfs->ns_last_cno = ri->ri_cno;
944 return 0;
946 failed:
947 brelse(bh_sum);
948 nilfs_dispose_segment_list(&segments);
949 return ret < 0 ? ret : nilfs_warn_segment_error(nilfs->ns_sb, ret);