// SPDX-License-Identifier: GPL-2.0+ /* * linux/fs/jbd2/recovery.c * * Written by Stephen C. Tweedie , 1999 * * Copyright 1999-2000 Red Hat Software --- All Rights Reserved * * Journal recovery routines for the generic filesystem journaling code; * part of the ext2fs journaling system. */ #ifndef __KERNEL__ #include "jfs_user.h" #else #include #include #include #include #include #include #include #endif /* * Maintain information about the progress of the recovery job, so that * the different passes can carry information between them. */ struct recovery_info { tid_t start_transaction; tid_t end_transaction; unsigned long head_block; int nr_replays; int nr_revokes; int nr_revoke_hits; }; static int do_one_pass(journal_t *journal, struct recovery_info *info, enum passtype pass); static int scan_revoke_records(journal_t *, struct buffer_head *, tid_t, struct recovery_info *); #ifdef __KERNEL__ /* Release readahead buffers after use */ static void journal_brelse_array(struct buffer_head *b[], int n) { while (--n >= 0) brelse (b[n]); } /* * When reading from the journal, we are going through the block device * layer directly and so there is no readahead being done for us. We * need to implement any readahead ourselves if we want it to happen at * all. Recovery is basically one long sequential read, so make sure we * do the IO in reasonably large chunks. * * This is not so critical that we need to be enormously clever about * the readahead size, though. 128K is a purely arbitrary, good-enough * fixed value. */ #define MAXBUF 8 static int do_readahead(journal_t *journal, unsigned int start) { int err; unsigned int max, nbufs, next; unsigned long long blocknr; struct buffer_head *bh; struct buffer_head * bufs[MAXBUF]; /* Do up to 128K of readahead */ max = start + (128 * 1024 / journal->j_blocksize); if (max > journal->j_total_len) max = journal->j_total_len; /* Do the readahead itself. We'll submit MAXBUF buffer_heads at * a time to the block device IO layer. */ nbufs = 0; for (next = start; next < max; next++) { err = jbd2_journal_bmap(journal, next, &blocknr); if (err) { printk(KERN_ERR "JBD2: bad block at offset %u\n", next); goto failed; } bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); if (!bh) { err = -ENOMEM; goto failed; } if (!buffer_uptodate(bh) && !buffer_locked(bh)) { bufs[nbufs++] = bh; if (nbufs == MAXBUF) { bh_readahead_batch(nbufs, bufs, 0); journal_brelse_array(bufs, nbufs); nbufs = 0; } } else brelse(bh); } if (nbufs) bh_readahead_batch(nbufs, bufs, 0); err = 0; failed: if (nbufs) journal_brelse_array(bufs, nbufs); return err; } #endif /* __KERNEL__ */ /* * Read a block from the journal */ static int jread(struct buffer_head **bhp, journal_t *journal, unsigned int offset) { int err; unsigned long long blocknr; struct buffer_head *bh; *bhp = NULL; if (offset >= journal->j_total_len) { printk(KERN_ERR "JBD2: corrupted journal superblock\n"); return -EFSCORRUPTED; } err = jbd2_journal_bmap(journal, offset, &blocknr); if (err) { printk(KERN_ERR "JBD2: bad block at offset %u\n", offset); return err; } bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); if (!bh) return -ENOMEM; if (!buffer_uptodate(bh)) { /* * If this is a brand new buffer, start readahead. * Otherwise, we assume we are already reading it. */ bool need_readahead = !buffer_req(bh); bh_read_nowait(bh, 0); if (need_readahead) do_readahead(journal, offset); wait_on_buffer(bh); } if (!buffer_uptodate(bh)) { printk(KERN_ERR "JBD2: Failed to read block at offset %u\n", offset); brelse(bh); return -EIO; } *bhp = bh; return 0; } static int jbd2_descriptor_block_csum_verify(journal_t *j, void *buf) { struct jbd2_journal_block_tail *tail; __be32 provided; __u32 calculated; if (!jbd2_journal_has_csum_v2or3(j)) return 1; tail = (struct jbd2_journal_block_tail *)((char *)buf + j->j_blocksize - sizeof(struct jbd2_journal_block_tail)); provided = tail->t_checksum; tail->t_checksum = 0; calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize); tail->t_checksum = provided; return provided == cpu_to_be32(calculated); } /* * Count the number of in-use tags in a journal descriptor block. */ static int count_tags(journal_t *journal, struct buffer_head *bh) { char * tagp; journal_block_tag_t tag; int nr = 0, size = journal->j_blocksize; int tag_bytes = journal_tag_bytes(journal); if (jbd2_journal_has_csum_v2or3(journal)) size -= sizeof(struct jbd2_journal_block_tail); tagp = &bh->b_data[sizeof(journal_header_t)]; while ((tagp - bh->b_data + tag_bytes) <= size) { memcpy(&tag, tagp, sizeof(tag)); nr++; tagp += tag_bytes; if (!(tag.t_flags & cpu_to_be16(JBD2_FLAG_SAME_UUID))) tagp += 16; if (tag.t_flags & cpu_to_be16(JBD2_FLAG_LAST_TAG)) break; } return nr; } /* Make sure we wrap around the log correctly! */ #define wrap(journal, var) \ do { \ if (var >= (journal)->j_last) \ var -= ((journal)->j_last - (journal)->j_first); \ } while (0) static int fc_do_one_pass(journal_t *journal, struct recovery_info *info, enum passtype pass) { unsigned int expected_commit_id = info->end_transaction; unsigned long next_fc_block; struct buffer_head *bh; int err = 0; next_fc_block = journal->j_fc_first; if (!journal->j_fc_replay_callback) return 0; while (next_fc_block <= journal->j_fc_last) { jbd2_debug(3, "Fast commit replay: next block %ld\n", next_fc_block); err = jread(&bh, journal, next_fc_block); if (err) { jbd2_debug(3, "Fast commit replay: read error\n"); break; } err = journal->j_fc_replay_callback(journal, bh, pass, next_fc_block - journal->j_fc_first, expected_commit_id); brelse(bh); next_fc_block++; if (err < 0 || err == JBD2_FC_REPLAY_STOP) break; err = 0; } if (err) jbd2_debug(3, "Fast commit replay failed, err = %d\n", err); return err; } /** * jbd2_journal_recover - recovers a on-disk journal * @journal: the journal to recover * * The primary function for recovering the log contents when mounting a * journaled device. * * Recovery is done in three passes. In the first pass, we look for the * end of the log. In the second, we assemble the list of revoke * blocks. In the third and final pass, we replay any un-revoked blocks * in the log. */ int jbd2_journal_recover(journal_t *journal) { int err, err2; journal_superblock_t * sb; struct recovery_info info; memset(&info, 0, sizeof(info)); sb = journal->j_superblock; /* * The journal superblock's s_start field (the current log head) * is always zero if, and only if, the journal was cleanly * unmounted. */ if (!sb->s_start) { jbd2_debug(1, "No recovery required, last transaction %d, head block %u\n", be32_to_cpu(sb->s_sequence), be32_to_cpu(sb->s_head)); journal->j_transaction_sequence = be32_to_cpu(sb->s_sequence) + 1; journal->j_head = be32_to_cpu(sb->s_head); return 0; } err = do_one_pass(journal, &info, PASS_SCAN); if (!err) err = do_one_pass(journal, &info, PASS_REVOKE); if (!err) err = do_one_pass(journal, &info, PASS_REPLAY); jbd2_debug(1, "JBD2: recovery, exit status %d, " "recovered transactions %u to %u\n", err, info.start_transaction, info.end_transaction); jbd2_debug(1, "JBD2: Replayed %d and revoked %d/%d blocks\n", info.nr_replays, info.nr_revoke_hits, info.nr_revokes); /* Restart the log at the next transaction ID, thus invalidating * any existing commit records in the log. */ journal->j_transaction_sequence = ++info.end_transaction; journal->j_head = info.head_block; jbd2_debug(1, "JBD2: last transaction %d, head block %lu\n", journal->j_transaction_sequence, journal->j_head); jbd2_journal_clear_revoke(journal); err2 = sync_blockdev(journal->j_fs_dev); if (!err) err = err2; err2 = jbd2_check_fs_dev_write_error(journal); if (!err) err = err2; /* Make sure all replayed data is on permanent storage */ if (journal->j_flags & JBD2_BARRIER) { err2 = blkdev_issue_flush(journal->j_fs_dev); if (!err) err = err2; } return err; } /** * jbd2_journal_skip_recovery - Start journal and wipe exiting records * @journal: journal to startup * * Locate any valid recovery information from the journal and set up the * journal structures in memory to ignore it (presumably because the * caller has evidence that it is out of date). * This function doesn't appear to be exported.. * * We perform one pass over the journal to allow us to tell the user how * much recovery information is being erased, and to let us initialise * the journal transaction sequence numbers to the next unused ID. */ int jbd2_journal_skip_recovery(journal_t *journal) { int err; struct recovery_info info; memset (&info, 0, sizeof(info)); err = do_one_pass(journal, &info, PASS_SCAN); if (err) { printk(KERN_ERR "JBD2: error %d scanning journal\n", err); ++journal->j_transaction_sequence; journal->j_head = journal->j_first; } else { #ifdef CONFIG_JBD2_DEBUG int dropped = info.end_transaction - be32_to_cpu(journal->j_superblock->s_sequence); jbd2_debug(1, "JBD2: ignoring %d transaction%s from the journal.\n", dropped, str_plural(dropped)); #endif journal->j_transaction_sequence = ++info.end_transaction; journal->j_head = info.head_block; } journal->j_tail = 0; return err; } static inline unsigned long long read_tag_block(journal_t *journal, journal_block_tag_t *tag) { unsigned long long block = be32_to_cpu(tag->t_blocknr); if (jbd2_has_feature_64bit(journal)) block |= (u64)be32_to_cpu(tag->t_blocknr_high) << 32; return block; } /* * calc_chksums calculates the checksums for the blocks described in the * descriptor block. */ static int calc_chksums(journal_t *journal, struct buffer_head *bh, unsigned long *next_log_block, __u32 *crc32_sum) { int i, num_blks, err; unsigned long io_block; struct buffer_head *obh; num_blks = count_tags(journal, bh); /* Calculate checksum of the descriptor block. */ *crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size); for (i = 0; i < num_blks; i++) { io_block = (*next_log_block)++; wrap(journal, *next_log_block); err = jread(&obh, journal, io_block); if (err) { printk(KERN_ERR "JBD2: IO error %d recovering block " "%lu in log\n", err, io_block); return 1; } else { *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data, obh->b_size); } put_bh(obh); } return 0; } static int jbd2_commit_block_csum_verify(journal_t *j, void *buf) { struct commit_header *h; __be32 provided; __u32 calculated; if (!jbd2_journal_has_csum_v2or3(j)) return 1; h = buf; provided = h->h_chksum[0]; h->h_chksum[0] = 0; calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize); h->h_chksum[0] = provided; return provided == cpu_to_be32(calculated); } static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag, journal_block_tag3_t *tag3, void *buf, __u32 sequence) { __u32 csum32; __be32 seq; if (!jbd2_journal_has_csum_v2or3(j)) return 1; seq = cpu_to_be32(sequence); csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq)); csum32 = jbd2_chksum(j, csum32, buf, j->j_blocksize); if (jbd2_has_feature_csum3(j)) return tag3->t_checksum == cpu_to_be32(csum32); else return tag->t_checksum == cpu_to_be16(csum32); } static int do_one_pass(journal_t *journal, struct recovery_info *info, enum passtype pass) { unsigned int first_commit_ID, next_commit_ID; unsigned long next_log_block, head_block; int err, success = 0; journal_superblock_t * sb; journal_header_t * tmp; struct buffer_head * bh; unsigned int sequence; int blocktype; int tag_bytes = journal_tag_bytes(journal); __u32 crc32_sum = ~0; /* Transactional Checksums */ int descr_csum_size = 0; int block_error = 0; bool need_check_commit_time = false; __u64 last_trans_commit_time = 0, commit_time; /* * First thing is to establish what we expect to find in the log * (in terms of transaction IDs), and where (in terms of log * block offsets): query the superblock. */ sb = journal->j_superblock; next_commit_ID = be32_to_cpu(sb->s_sequence); next_log_block = be32_to_cpu(sb->s_start); head_block = next_log_block; first_commit_ID = next_commit_ID; if (pass == PASS_SCAN) info->start_transaction = first_commit_ID; jbd2_debug(1, "Starting recovery pass %d\n", pass); /* * Now we walk through the log, transaction by transaction, * making sure that each transaction has a commit block in the * expected place. Each complete transaction gets replayed back * into the main filesystem. */ while (1) { int flags; char * tagp; journal_block_tag_t tag; struct buffer_head * obh; struct buffer_head * nbh; cond_resched(); /* If we already know where to stop the log traversal, * check right now that we haven't gone past the end of * the log. */ if (pass != PASS_SCAN) if (tid_geq(next_commit_ID, info->end_transaction)) break; jbd2_debug(2, "Scanning for sequence ID %u at %lu/%lu\n", next_commit_ID, next_log_block, journal->j_last); /* Skip over each chunk of the transaction looking * either the next descriptor block or the final commit * record. */ jbd2_debug(3, "JBD2: checking block %ld\n", next_log_block); err = jread(&bh, journal, next_log_block); if (err) goto failed; next_log_block++; wrap(journal, next_log_block); /* What kind of buffer is it? * * If it is a descriptor block, check that it has the * expected sequence number. Otherwise, we're all done * here. */ tmp = (journal_header_t *)bh->b_data; if (tmp->h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER)) { brelse(bh); break; } blocktype = be32_to_cpu(tmp->h_blocktype); sequence = be32_to_cpu(tmp->h_sequence); jbd2_debug(3, "Found magic %d, sequence %d\n", blocktype, sequence); if (sequence != next_commit_ID) { brelse(bh); break; } /* OK, we have a valid descriptor block which matches * all of the sequence number checks. What are we going * to do with it? That depends on the pass... */ switch(blocktype) { case JBD2_DESCRIPTOR_BLOCK: /* Verify checksum first */ if (jbd2_journal_has_csum_v2or3(journal)) descr_csum_size = sizeof(struct jbd2_journal_block_tail); if (descr_csum_size > 0 && !jbd2_descriptor_block_csum_verify(journal, bh->b_data)) { /* * PASS_SCAN can see stale blocks due to lazy * journal init. Don't error out on those yet. */ if (pass != PASS_SCAN) { pr_err("JBD2: Invalid checksum recovering block %lu in log\n", next_log_block); err = -EFSBADCRC; brelse(bh); goto failed; } need_check_commit_time = true; jbd2_debug(1, "invalid descriptor block found in %lu\n", next_log_block); } /* If it is a valid descriptor block, replay it * in pass REPLAY; if journal_checksums enabled, then * calculate checksums in PASS_SCAN, otherwise, * just skip over the blocks it describes. */ if (pass != PASS_REPLAY) { if (pass == PASS_SCAN && jbd2_has_feature_checksum(journal) && !need_check_commit_time && !info->end_transaction) { if (calc_chksums(journal, bh, &next_log_block, &crc32_sum)) { put_bh(bh); break; } put_bh(bh); continue; } next_log_block += count_tags(journal, bh); wrap(journal, next_log_block); put_bh(bh); continue; } /* A descriptor block: we can now write all of * the data blocks. Yay, useful work is finally * getting done here! */ tagp = &bh->b_data[sizeof(journal_header_t)]; while ((tagp - bh->b_data + tag_bytes) <= journal->j_blocksize - descr_csum_size) { unsigned long io_block; memcpy(&tag, tagp, sizeof(tag)); flags = be16_to_cpu(tag.t_flags); io_block = next_log_block++; wrap(journal, next_log_block); err = jread(&obh, journal, io_block); if (err) { /* Recover what we can, but * report failure at the end. */ success = err; printk(KERN_ERR "JBD2: IO error %d recovering " "block %lu in log\n", err, io_block); } else { unsigned long long blocknr; J_ASSERT(obh != NULL); blocknr = read_tag_block(journal, &tag); /* If the block has been * revoked, then we're all done * here. */ if (jbd2_journal_test_revoke (journal, blocknr, next_commit_ID)) { brelse(obh); ++info->nr_revoke_hits; goto skip_write; } /* Look for block corruption */ if (!jbd2_block_tag_csum_verify( journal, &tag, (journal_block_tag3_t *)tagp, obh->b_data, be32_to_cpu(tmp->h_sequence))) { brelse(obh); success = -EFSBADCRC; printk(KERN_ERR "JBD2: Invalid " "checksum recovering " "data block %llu in " "journal block %lu\n", blocknr, io_block); block_error = 1; goto skip_write; } /* Find a buffer for the new * data being restored */ nbh = __getblk(journal->j_fs_dev, blocknr, journal->j_blocksize); if (nbh == NULL) { printk(KERN_ERR "JBD2: Out of memory " "during recovery.\n"); err = -ENOMEM; brelse(bh); brelse(obh); goto failed; } lock_buffer(nbh); memcpy(nbh->b_data, obh->b_data, journal->j_blocksize); if (flags & JBD2_FLAG_ESCAPE) { *((__be32 *)nbh->b_data) = cpu_to_be32(JBD2_MAGIC_NUMBER); } BUFFER_TRACE(nbh, "marking dirty"); set_buffer_uptodate(nbh); mark_buffer_dirty(nbh); BUFFER_TRACE(nbh, "marking uptodate"); ++info->nr_replays; unlock_buffer(nbh); brelse(obh); brelse(nbh); } skip_write: tagp += tag_bytes; if (!(flags & JBD2_FLAG_SAME_UUID)) tagp += 16; if (flags & JBD2_FLAG_LAST_TAG) break; } brelse(bh); continue; case JBD2_COMMIT_BLOCK: /* How to differentiate between interrupted commit * and journal corruption ? * * {nth transaction} * Checksum Verification Failed * | * ____________________ * | | * async_commit sync_commit * | | * | GO TO NEXT "Journal Corruption" * | TRANSACTION * | * {(n+1)th transanction} * | * _______|______________ * | | * Commit block found Commit block not found * | | * "Journal Corruption" | * _____________|_________ * | | * nth trans corrupt OR nth trans * and (n+1)th interrupted interrupted * before commit block * could reach the disk. * (Cannot find the difference in above * mentioned conditions. Hence assume * "Interrupted Commit".) */ commit_time = be64_to_cpu( ((struct commit_header *)bh->b_data)->h_commit_sec); /* * If need_check_commit_time is set, it means we are in * PASS_SCAN and csum verify failed before. If * commit_time is increasing, it's the same journal, * otherwise it is stale journal block, just end this * recovery. */ if (need_check_commit_time) { if (commit_time >= last_trans_commit_time) { pr_err("JBD2: Invalid checksum found in transaction %u\n", next_commit_ID); err = -EFSBADCRC; brelse(bh); goto failed; } ignore_crc_mismatch: /* * It likely does not belong to same journal, * just end this recovery with success. */ jbd2_debug(1, "JBD2: Invalid checksum ignored in transaction %u, likely stale data\n", next_commit_ID); brelse(bh); goto done; } /* * Found an expected commit block: if checksums * are present, verify them in PASS_SCAN; else not * much to do other than move on to the next sequence * number. */ if (pass == PASS_SCAN && jbd2_has_feature_checksum(journal)) { struct commit_header *cbh = (struct commit_header *)bh->b_data; unsigned found_chksum = be32_to_cpu(cbh->h_chksum[0]); if (info->end_transaction) { journal->j_failed_commit = info->end_transaction; brelse(bh); break; } /* Neither checksum match nor unused? */ if (!((crc32_sum == found_chksum && cbh->h_chksum_type == JBD2_CRC32_CHKSUM && cbh->h_chksum_size == JBD2_CRC32_CHKSUM_SIZE) || (cbh->h_chksum_type == 0 && cbh->h_chksum_size == 0 && found_chksum == 0))) goto chksum_error; crc32_sum = ~0; } if (pass == PASS_SCAN && !jbd2_commit_block_csum_verify(journal, bh->b_data)) { chksum_error: if (commit_time < last_trans_commit_time) goto ignore_crc_mismatch; info->end_transaction = next_commit_ID; info->head_block = head_block; if (!jbd2_has_feature_async_commit(journal)) { journal->j_failed_commit = next_commit_ID; brelse(bh); break; } } if (pass == PASS_SCAN) { last_trans_commit_time = commit_time; head_block = next_log_block; } brelse(bh); next_commit_ID++; continue; case JBD2_REVOKE_BLOCK: /* * Check revoke block crc in pass_scan, if csum verify * failed, check commit block time later. */ if (pass == PASS_SCAN && !jbd2_descriptor_block_csum_verify(journal, bh->b_data)) { jbd2_debug(1, "JBD2: invalid revoke block found in %lu\n", next_log_block); need_check_commit_time = true; } /* If we aren't in the REVOKE pass, then we can * just skip over this block. */ if (pass != PASS_REVOKE) { brelse(bh); continue; } err = scan_revoke_records(journal, bh, next_commit_ID, info); brelse(bh); if (err) goto failed; continue; default: jbd2_debug(3, "Unrecognised magic %d, end of scan.\n", blocktype); brelse(bh); goto done; } } done: /* * We broke out of the log scan loop: either we came to the * known end of the log or we found an unexpected block in the * log. If the latter happened, then we know that the "current" * transaction marks the end of the valid log. */ if (pass == PASS_SCAN) { if (!info->end_transaction) info->end_transaction = next_commit_ID; if (!info->head_block) info->head_block = head_block; } else { /* It's really bad news if different passes end up at * different places (but possible due to IO errors). */ if (info->end_transaction != next_commit_ID) { printk(KERN_ERR "JBD2: recovery pass %d ended at " "transaction %u, expected %u\n", pass, next_commit_ID, info->end_transaction); if (!success) success = -EIO; } } if (jbd2_has_feature_fast_commit(journal) && pass != PASS_REVOKE) { err = fc_do_one_pass(journal, info, pass); if (err) success = err; } if (block_error && success == 0) success = -EIO; return success; failed: return err; } /* Scan a revoke record, marking all blocks mentioned as revoked. */ static int scan_revoke_records(journal_t *journal, struct buffer_head *bh, tid_t sequence, struct recovery_info *info) { jbd2_journal_revoke_header_t *header; int offset, max; unsigned csum_size = 0; __u32 rcount; int record_len = 4; header = (jbd2_journal_revoke_header_t *) bh->b_data; offset = sizeof(jbd2_journal_revoke_header_t); rcount = be32_to_cpu(header->r_count); if (jbd2_journal_has_csum_v2or3(journal)) csum_size = sizeof(struct jbd2_journal_block_tail); if (rcount > journal->j_blocksize - csum_size) return -EINVAL; max = rcount; if (jbd2_has_feature_64bit(journal)) record_len = 8; while (offset + record_len <= max) { unsigned long long blocknr; int err; if (record_len == 4) blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset))); else blocknr = be64_to_cpu(* ((__be64 *) (bh->b_data+offset))); offset += record_len; err = jbd2_journal_set_revoke(journal, blocknr, sequence); if (err) return err; ++info->nr_revokes; } return 0; }