renegade-project/linux-next
2
0
Fork 0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-25 21:54:06 +08:00
Code
2961980972
linux-next/fs/jbd2/recovery.c
Hidehiro Kawai 44519faf22 jbd2: fix error handling for checkpoint io 
When a checkpointing IO fails, current JBD2 code doesn't check the
error and continue journaling.  This means latest metadata can be
lost from both the journal and filesystem.

This patch leaves the failed metadata blocks in the journal space
and aborts journaling in the case of jbd2_log_do_checkpoint().
To achieve this, we need to do:

1. don't remove the failed buffer from the checkpoint list where in
   the case of __try_to_free_cp_buf() because it may be released or
   overwritten by a later transaction
2. jbd2_log_do_checkpoint() is the last chance, remove the failed
   buffer from the checkpoint list and abort the journal
3. when checkpointing fails, don't update the journal super block to
   prevent the journaled contents from being cleaned.  For safety,
   don't update j_tail and j_tail_sequence either
4. when checkpointing fails, notify this error to the ext4 layer so
   that ext4 don't clear the needs_recovery flag, otherwise the
   journaled contents are ignored and cleaned in the recovery phase
5. if the recovery fails, keep the needs_recovery flag
6. prevent jbd2_cleanup_journal_tail() from being called between
   __jbd2_journal_drop_transaction() and jbd2_journal_abort()
   (a possible race issue between jbd2_log_do_checkpoint()s called by
   jbd2_journal_flush() and __jbd2_log_wait_for_space())

Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2008-10-10 20:29:13 -04:00

746 lines
19 KiB
C
Raw Blame History

/*
* linux/fs/jbd2/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/jbd2.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/crc32.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 = jbd2_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 = jbd2_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(JBD2_FLAG_SAME_UUID)))
tagp += 16;
if (tag->t_flags & cpu_to_be32(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)
/**
* 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) {
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;
jbd2_journal_clear_revoke(journal);
err2 = sync_blockdev(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 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 jbd2_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_JBD2_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 > JBD2_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 *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 "JBD: 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 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;
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(JBD2_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 JBD2_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 &&
JBD2_HAS_COMPAT_FEATURE(journal,
JBD2_FEATURE_COMPAT_CHECKSUM) &&
!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) {
unsigned 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 %ld 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 (jbd2_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 & 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;
/* ll_rw_block(WRITE, 1, &nbh); */
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".)
*/
/* 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_COMPAT_FEATURE(journal,
JBD2_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;
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;
if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)){
journal->j_failed_commit =
next_commit_ID;
brelse(bh);
break;
}
}
crc32_sum = ~0;
}
brelse(bh);
next_commit_ID++;
continue;
case JBD2_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)
{
jbd2_journal_revoke_header_t *header;
int offset, max;
int record_len = 4;
header = (jbd2_journal_revoke_header_t *) bh->b_data;
offset = sizeof(jbd2_journal_revoke_header_t);
max = be32_to_cpu(header->r_count);
if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
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;
}
View Git Blame Copy Permalink