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jbd2: fix ocfs2 corrupt when updating journal superblock fails
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If updating journal superblock fails after journal data has been
flushed, the error is omitted and this will mislead the caller as a
normal case.  In ocfs2, the checkpoint will be treated successfully
and the other node can get the lock to update. Since the sb_start is
still pointing to the old log block, it will rewrite the journal data
during journal recovery by the other node. Thus the new updates will
be overwritten and ocfs2 corrupts.  So in above case we have to return
the error, and ocfs2_commit_cache will take care of the error and
prevent the other node to do update first.  And only after recovering
journal it can do the new updates.

The issue discussion mail can be found at:
https://oss.oracle.com/pipermail/ocfs2-devel/2015-June/010856.html
http://comments.gmane.org/gmane.comp.file-systems.ext4/48841

[ Fixed bug in patch which allowed a non-negative error return from
  jbd2_cleanup_journal_tail() to leak out of jbd2_fjournal_flush(); this
  was causing xfstests ext4/306 to fail. -- Ted ]

Reported-by: Yiwen Jiang <[email protected]>
Signed-off-by: Joseph Qi <[email protected]>
Signed-off-by: Theodore Ts'o <[email protected]>
Tested-by: Yiwen Jiang <[email protected]>
Cc: Junxiao Bi <[email protected]>
Cc: [email protected]
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@josephhz @tytso
josephhz authored and tytso committed Jun 15, 2015
1 parent 97b4af2 commit 6f6a6fd
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Showing 3 changed files with 35 additions and 12 deletions.
5 changes: 2 additions & 3 deletions fs/jbd2/checkpoint.c
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Original file line number Diff line number Diff line change
Expand Up @@ -390,7 +390,7 @@ int jbd2_cleanup_journal_tail(journal_t *journal)
unsigned long blocknr;

if (is_journal_aborted(journal))
return 1;
return -EIO;

if (!jbd2_journal_get_log_tail(journal, &first_tid, &blocknr))
return 1;
Expand All @@ -407,8 +407,7 @@ int jbd2_cleanup_journal_tail(journal_t *journal)
if (journal->j_flags & JBD2_BARRIER)
blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);

__jbd2_update_log_tail(journal, first_tid, blocknr);
return 0;
return __jbd2_update_log_tail(journal, first_tid, blocknr);
}


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38 changes: 31 additions & 7 deletions fs/jbd2/journal.c
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Original file line number Diff line number Diff line change
Expand Up @@ -876,9 +876,10 @@ int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
*
* Requires j_checkpoint_mutex
*/
void __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
int __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
{
unsigned long freed;
int ret;

BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));

Expand All @@ -888,7 +889,10 @@ void __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
* space and if we lose sb update during power failure we'd replay
* old transaction with possibly newly overwritten data.
*/
jbd2_journal_update_sb_log_tail(journal, tid, block, WRITE_FUA);
ret = jbd2_journal_update_sb_log_tail(journal, tid, block, WRITE_FUA);
if (ret)
goto out;

write_lock(&journal->j_state_lock);
freed = block - journal->j_tail;
if (block < journal->j_tail)
Expand All @@ -904,6 +908,9 @@ void __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
journal->j_tail_sequence = tid;
journal->j_tail = block;
write_unlock(&journal->j_state_lock);

out:
return ret;
}

/*
Expand Down Expand Up @@ -1322,7 +1329,7 @@ static int journal_reset(journal_t *journal)
return jbd2_journal_start_thread(journal);
}

static void jbd2_write_superblock(journal_t *journal, int write_op)
static int jbd2_write_superblock(journal_t *journal, int write_op)
{
struct buffer_head *bh = journal->j_sb_buffer;
journal_superblock_t *sb = journal->j_superblock;
Expand Down Expand Up @@ -1361,7 +1368,10 @@ static void jbd2_write_superblock(journal_t *journal, int write_op)
printk(KERN_ERR "JBD2: Error %d detected when updating "
"journal superblock for %s.\n", ret,
journal->j_devname);
jbd2_journal_abort(journal, ret);
}

return ret;
}

/**
Expand All @@ -1374,10 +1384,11 @@ static void jbd2_write_superblock(journal_t *journal, int write_op)
* Update a journal's superblock information about log tail and write it to
* disk, waiting for the IO to complete.
*/
void jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
int jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
unsigned long tail_block, int write_op)
{
journal_superblock_t *sb = journal->j_superblock;
int ret;

BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
jbd_debug(1, "JBD2: updating superblock (start %lu, seq %u)\n",
Expand All @@ -1386,13 +1397,18 @@ void jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
sb->s_sequence = cpu_to_be32(tail_tid);
sb->s_start = cpu_to_be32(tail_block);

jbd2_write_superblock(journal, write_op);
ret = jbd2_write_superblock(journal, write_op);
if (ret)
goto out;

/* Log is no longer empty */
write_lock(&journal->j_state_lock);
WARN_ON(!sb->s_sequence);
journal->j_flags &= ~JBD2_FLUSHED;
write_unlock(&journal->j_state_lock);

out:
return ret;
}

/**
Expand Down Expand Up @@ -1941,7 +1957,14 @@ int jbd2_journal_flush(journal_t *journal)
return -EIO;

mutex_lock(&journal->j_checkpoint_mutex);
jbd2_cleanup_journal_tail(journal);
if (!err) {
err = jbd2_cleanup_journal_tail(journal);
if (err < 0) {
mutex_unlock(&journal->j_checkpoint_mutex);
goto out;
}
err = 0;
}

/* Finally, mark the journal as really needing no recovery.
* This sets s_start==0 in the underlying superblock, which is
Expand All @@ -1957,7 +1980,8 @@ int jbd2_journal_flush(journal_t *journal)
J_ASSERT(journal->j_head == journal->j_tail);
J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
write_unlock(&journal->j_state_lock);
return 0;
out:
return err;
}

/**
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4 changes: 2 additions & 2 deletions include/linux/jbd2.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1035,7 +1035,7 @@ struct buffer_head *jbd2_journal_get_descriptor_buffer(journal_t *journal);
int jbd2_journal_next_log_block(journal_t *, unsigned long long *);
int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
unsigned long *block);
void __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block);
int __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block);
void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block);

/* Commit management */
Expand Down Expand Up @@ -1157,7 +1157,7 @@ extern int jbd2_journal_recover (journal_t *journal);
extern int jbd2_journal_wipe (journal_t *, int);
extern int jbd2_journal_skip_recovery (journal_t *);
extern void jbd2_journal_update_sb_errno(journal_t *);
extern void jbd2_journal_update_sb_log_tail (journal_t *, tid_t,
extern int jbd2_journal_update_sb_log_tail (journal_t *, tid_t,
unsigned long, int);
extern void __jbd2_journal_abort_hard (journal_t *);
extern void jbd2_journal_abort (journal_t *, int);
Expand Down

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