diff options
Diffstat (limited to 'kernel/fs/jbd/recovery.c')
| -rw-r--r-- | kernel/fs/jbd/recovery.c | 594 |
1 files changed, 0 insertions, 594 deletions
diff --git a/kernel/fs/jbd/recovery.c b/kernel/fs/jbd/recovery.c deleted file mode 100644 index a748fe214..000000000 --- a/kernel/fs/jbd/recovery.c +++ /dev/null @@ -1,594 +0,0 @@ -/* - * 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 "jfs_user.h" -#else -#include <linux/time.h> -#include <linux/fs.h> -#include <linux/jbd.h> -#include <linux/errno.h> -#include <linux/blkdev.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 int 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 int 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(struct buffer_head *bh, int size) -{ - char * tagp; - journal_block_tag_t * tag; - int nr = 0; - - tagp = &bh->b_data[sizeof(journal_header_t)]; - - while ((tagp - bh->b_data + sizeof(journal_block_tag_t)) <= size) { - tag = (journal_block_tag_t *) tagp; - - nr++; - tagp += sizeof(journal_block_tag_t); - 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, 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) { - 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); - err2 = sync_blockdev(journal->j_fs_dev); - if (!err) - err = err2; - /* Flush disk caches to get replayed data on the permanent storage */ - if (journal->j_flags & JFS_BARRIER) { - err2 = blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL); - if (!err) - err = err2; - } - - 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; - struct recovery_info info; - - memset (&info, 0, sizeof(info)); - - 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(journal->j_superblock->s_sequence); - jbd_debug(1, - "JBD: ignoring %d transaction%s from the journal.\n", - dropped, (dropped == 1) ? "" : "s"); -#endif - journal->j_transaction_sequence = ++info.end_transaction; - } - - journal->j_tail = 0; - return err; -} - -static int do_one_pass(journal_t *journal, - struct recovery_info *info, enum passtype pass) -{ - unsigned int first_commit_ID, next_commit_ID; - unsigned int next_log_block; - int err, success = 0; - journal_superblock_t * sb; - journal_header_t * tmp; - struct buffer_head * bh; - unsigned int sequence; - int blocktype; - - /* - * 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 %u/%u\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 %u\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; otherwise, just skip over the - * blocks it describes. */ - if (pass != PASS_REPLAY) { - next_log_block += - count_tags(bh, journal->j_blocksize); - 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 +sizeof(journal_block_tag_t)) - <= journal->j_blocksize) { - unsigned int 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 %u in log\n", - err, io_block); - } else { - unsigned int blocknr; - - J_ASSERT(obh != NULL); - blocknr = be32_to_cpu(tag->t_blocknr); - - /* 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) { - *((__be32 *)nbh->b_data) = - 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 += sizeof(journal_block_tag_t); - if (!(flags & JFS_FLAG_SAME_UUID)) - tagp += 16; - - if (flags & JFS_FLAG_LAST_TAG) - break; - } - - brelse(bh); - continue; - - case JFS_COMMIT_BLOCK: - /* Found an expected commit block: not much to - * do other than move on to the next sequence - * number. */ - 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) - 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; - - header = (journal_revoke_header_t *) bh->b_data; - offset = sizeof(journal_revoke_header_t); - max = be32_to_cpu(header->r_count); - - while (offset < max) { - unsigned int blocknr; - int err; - - blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset))); - offset += 4; - err = journal_set_revoke(journal, blocknr, sequence); - if (err) - return err; - ++info->nr_revokes; - } - return 0; -} |