nilfs2: use sb instance instead of nilfs_sb_info struct
[linux-3.10.git] / fs / nilfs2 / recovery.c
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  */
37 enum {
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 */
49 struct 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
59 static 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  */
104 static 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  */
142 int 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  */
192 static struct buffer_head *
193 nilfs_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  */
211 static 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;
243 out:
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  */
254 static 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  */
284 static 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  */
316 static 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
387 static void dispose_recovery_list(struct list_head *head)
388 {
389         while (!list_empty(head)) {
390                 struct nilfs_recovery_block *rb
391                         = list_entry(head->next,
392                                      struct nilfs_recovery_block, list);
393                 list_del(&rb->list);
394                 kfree(rb);
395         }
396 }
397
398 struct nilfs_segment_entry {
399         struct list_head        list;
400         __u64                   segnum;
401 };
402
403 static 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
416 void nilfs_dispose_segment_list(struct list_head *head)
417 {
418         while (!list_empty(head)) {
419                 struct nilfs_segment_entry *ent
420                         = list_entry(head->next,
421                                      struct nilfs_segment_entry, list);
422                 list_del(&ent->list);
423                 kfree(ent);
424         }
425 }
426
427 static 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
485 static 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, KM_USER0);
497         memcpy(kaddr + bh_offset(bh_org), bh_org->b_data, bh_org->b_size);
498         kunmap_atomic(kaddr, KM_USER0);
499         brelse(bh_org);
500         return 0;
501 }
502
503 static 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  */
578 static 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
702 static 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  */
743 int 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  */
812 int 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 }