| /* |
| * linux/fs/jbd/recovery.c |
| * |
| * Written by Stephen C. Tweedie <sct@redhat.com>, 1999 |
| * |
| * Copyright 1999-2000 Red Hat Software --- All Rights Reserved |
| * |
| * This file is part of the Linux kernel and is made available under |
| * the terms of the GNU General Public License, version 2, or at your |
| * option, any later version, incorporated herein by reference. |
| * |
| * Journal recovery routines for the generic filesystem journaling code; |
| * part of the ext2fs journaling system. |
| */ |
| |
| #ifndef __KERNEL__ |
| #include "config.h" |
| #include "jfs_user.h" |
| #else |
| #include <linux/time.h> |
| #include <linux/fs.h> |
| #include <linux/jbd.h> |
| #include <linux/errno.h> |
| #include <linux/slab.h> |
| #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; |
| |
| int nr_replays; |
| int nr_revokes; |
| int nr_revoke_hits; |
| }; |
| |
| enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY}; |
| 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_maxlen) |
| max = journal->j_maxlen; |
| |
| /* 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 = journal_bmap(journal, next, &blocknr); |
| |
| if (err) { |
| printk (KERN_ERR "JBD: 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) { |
| ll_rw_block(READ, nbufs, bufs); |
| journal_brelse_array(bufs, nbufs); |
| nbufs = 0; |
| } |
| } else |
| brelse(bh); |
| } |
| |
| if (nbufs) |
| ll_rw_block(READ, nbufs, bufs); |
| 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_maxlen) { |
| printk(KERN_ERR "JBD: corrupted journal superblock\n"); |
| return -EIO; |
| } |
| |
| err = journal_bmap(journal, offset, &blocknr); |
| |
| if (err) { |
| printk (KERN_ERR "JBD: 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. */ |
| if (!buffer_req(bh)) |
| do_readahead(journal, offset); |
| wait_on_buffer(bh); |
| } |
| |
| if (!buffer_uptodate(bh)) { |
| printk (KERN_ERR "JBD: Failed to read block at offset %u\n", |
| offset); |
| brelse(bh); |
| return -EIO; |
| } |
| |
| *bhp = bh; |
| return 0; |
| } |
| |
| |
| /* |
| * 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); |
| |
| tagp = &bh->b_data[sizeof(journal_header_t)]; |
| |
| while ((tagp - bh->b_data + tag_bytes) <= size) { |
| tag = (journal_block_tag_t *) tagp; |
| |
| nr++; |
| tagp += tag_bytes; |
| if (!(tag->t_flags & cpu_to_be32(JFS_FLAG_SAME_UUID))) |
| tagp += 16; |
| |
| if (tag->t_flags & cpu_to_be32(JFS_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) |
| |
| /** |
| * 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 journal_recover(journal_t *journal) |
| { |
| int err; |
| 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) { |
| jbd_debug(1, "No recovery required, last transaction %d\n", |
| be32_to_cpu(sb->s_sequence)); |
| journal->j_transaction_sequence = be32_to_cpu(sb->s_sequence) + 1; |
| 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); |
| |
| jbd_debug(1, "JBD: recovery, exit status %d, " |
| "recovered transactions %u to %u\n", |
| err, info.start_transaction, info.end_transaction); |
| jbd_debug(1, "JBD: 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_clear_revoke(journal); |
| sync_blockdev(journal->j_fs_dev); |
| return err; |
| } |
| |
| /** |
| * 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 does'nt appear to be exorted.. |
| * |
| * 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 journal_skip_recovery(journal_t *journal) |
| { |
| int err; |
| journal_superblock_t * sb; |
| |
| struct recovery_info info; |
| |
| memset (&info, 0, sizeof(info)); |
| sb = journal->j_superblock; |
| |
| err = do_one_pass(journal, &info, PASS_SCAN); |
| |
| if (err) { |
| printk(KERN_ERR "JBD: error %d scanning journal\n", err); |
| ++journal->j_transaction_sequence; |
| } else { |
| #ifdef CONFIG_JBD_DEBUG |
| int dropped = info.end_transaction - be32_to_cpu(sb->s_sequence); |
| #endif |
| jbd_debug(1, |
| "JBD: ignoring %d transaction%s from the journal.\n", |
| dropped, (dropped == 1) ? "" : "s"); |
| journal->j_transaction_sequence = ++info.end_transaction; |
| } |
| |
| journal->j_tail = 0; |
| return err; |
| } |
| |
| static inline unsigned long long read_tag_block(int tag_bytes, journal_block_tag_t *tag) |
| { |
| unsigned long long block = be32_to_cpu(tag->t_blocknr); |
| if (tag_bytes > JBD_TAG_SIZE32) |
| 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 long *next_log_block, __u32 *crc32_sum) |
| { |
| int i, num_blks, err; |
| unsigned long 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 "JBD: IO error %d recovering block " |
| "%llu in log\n", err, io_block); |
| return 1; |
| } else { |
| *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data, |
| obh->b_size); |
| } |
| brelse(obh); |
| } |
| return 0; |
| } |
| |
| 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 long next_log_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 */ |
| |
| /* Precompute the maximum metadata descriptors in a descriptor block */ |
| int MAX_BLOCKS_PER_DESC; |
| MAX_BLOCKS_PER_DESC = ((journal->j_blocksize-sizeof(journal_header_t)) |
| / tag_bytes); |
| |
| /* |
| * 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); |
| |
| first_commit_ID = next_commit_ID; |
| if (pass == PASS_SCAN) |
| info->start_transaction = first_commit_ID; |
| |
| jbd_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; |
| |
| jbd_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. */ |
| |
| jbd_debug(3, "JBD: 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(JFS_MAGIC_NUMBER)) { |
| brelse(bh); |
| break; |
| } |
| |
| blocktype = be32_to_cpu(tmp->h_blocktype); |
| sequence = be32_to_cpu(tmp->h_sequence); |
| jbd_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 JFS_DESCRIPTOR_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 && |
| JFS_HAS_COMPAT_FEATURE(journal, |
| JFS_FEATURE_COMPAT_CHECKSUM) && |
| !info->end_transaction) { |
| if (calc_chksums(journal, bh, |
| &next_log_block, |
| &crc32_sum)) { |
| brelse(bh); |
| break; |
| } |
| brelse(bh); |
| continue; |
| } |
| next_log_block += count_tags(journal, bh); |
| wrap(journal, next_log_block); |
| brelse(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) { |
| unsigned long long io_block; |
| |
| tag = (journal_block_tag_t *) tagp; |
| flags = be32_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 |
| "JBD: IO error %d recovering " |
| "block %llu in log\n", |
| err, io_block); |
| } else { |
| unsigned long long blocknr; |
| |
| J_ASSERT(obh != NULL); |
| blocknr = read_tag_block(tag_bytes, |
| tag); |
| |
| /* If the block has been |
| * revoked, then we're all done |
| * here. */ |
| if (journal_test_revoke |
| (journal, blocknr, |
| next_commit_ID)) { |
| brelse(obh); |
| ++info->nr_revoke_hits; |
| 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 |
| "JBD: 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 & JFS_FLAG_ESCAPE) { |
| journal_header_t *header; |
| |
| header = (journal_header_t *) &nbh->b_data[0]; |
| header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER); |
| } |
| |
| BUFFER_TRACE(nbh, "marking dirty"); |
| set_buffer_uptodate(nbh); |
| mark_buffer_dirty(nbh); |
| BUFFER_TRACE(nbh, "marking uptodate"); |
| ++info->nr_replays; |
| /* ll_rw_block(WRITE, 1, &nbh); */ |
| unlock_buffer(nbh); |
| brelse(obh); |
| brelse(nbh); |
| } |
| |
| skip_write: |
| tagp += tag_bytes; |
| if (!(flags & JFS_FLAG_SAME_UUID)) |
| tagp += 16; |
| |
| if (flags & JFS_FLAG_LAST_TAG) |
| break; |
| } |
| |
| brelse(bh); |
| continue; |
| |
| case JFS_COMMIT_BLOCK: |
| jbd_debug(3, "Commit block for #%u found\n", |
| next_commit_ID); |
| /* 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".) |
| */ |
| |
| /* 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 && |
| JFS_HAS_COMPAT_FEATURE(journal, |
| JFS_FEATURE_COMPAT_CHECKSUM)) { |
| int chksum_err, chksum_seen; |
| struct commit_header *cbh = |
| (struct commit_header *)bh->b_data; |
| unsigned found_chksum = |
| be32_to_cpu(cbh->h_chksum[0]); |
| |
| chksum_err = chksum_seen = 0; |
| |
| jbd_debug(3, "Checksums %x %x\n", |
| crc32_sum, found_chksum); |
| if (info->end_transaction) { |
| journal->j_failed_commit = |
| info->end_transaction; |
| brelse(bh); |
| break; |
| } |
| |
| if (crc32_sum == found_chksum && |
| cbh->h_chksum_type == JBD2_CRC32_CHKSUM && |
| cbh->h_chksum_size == |
| JBD2_CRC32_CHKSUM_SIZE) |
| chksum_seen = 1; |
| else if (!(cbh->h_chksum_type == 0 && |
| cbh->h_chksum_size == 0 && |
| found_chksum == 0 && |
| !chksum_seen)) |
| /* |
| * If fs is mounted using an old kernel and then |
| * kernel with journal_chksum is used then we |
| * get a situation where the journal flag has |
| * checksum flag set but checksums are not |
| * present i.e chksum = 0, in the individual |
| * commit blocks. |
| * Hence to avoid checksum failures, in this |
| * situation, this extra check is added. |
| */ |
| chksum_err = 1; |
| |
| if (chksum_err) { |
| info->end_transaction = next_commit_ID; |
| jbd_debug(1, "Checksum_err %x %x\n", |
| crc32_sum, found_chksum); |
| if (!JFS_HAS_INCOMPAT_FEATURE(journal, |
| JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)){ |
| journal->j_failed_commit = |
| next_commit_ID; |
| brelse(bh); |
| break; |
| } |
| } |
| crc32_sum = ~0; |
| } |
| brelse(bh); |
| next_commit_ID++; |
| continue; |
| |
| case JFS_REVOKE_BLOCK: |
| /* 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: |
| jbd_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; |
| } 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 "JBD: recovery pass %d ended at " |
| "transaction %u, expected %u\n", |
| pass, next_commit_ID, info->end_transaction); |
| if (!success) |
| 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) |
| { |
| journal_revoke_header_t *header; |
| int offset, max; |
| int record_len = 4; |
| |
| header = (journal_revoke_header_t *) bh->b_data; |
| offset = sizeof(journal_revoke_header_t); |
| max = be32_to_cpu(header->r_count); |
| |
| if (JFS_HAS_INCOMPAT_FEATURE(journal, JFS_FEATURE_INCOMPAT_64BIT)) |
| record_len = 8; |
| |
| while (offset < max) { |
| unsigned long long blocknr; |
| int err; |
| |
| if (record_len == 4) |
| blocknr = ext2fs_be32_to_cpu(*((__be32 *)(bh->b_data + |
| offset))); |
| else |
| blocknr = ext2fs_be64_to_cpu(*((__be64 *)(bh->b_data + |
| offset))); |
| offset += record_len; |
| err = journal_set_revoke(journal, blocknr, sequence); |
| if (err) |
| return err; |
| ++info->nr_revokes; |
| } |
| return 0; |
| } |