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author | OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> | 2016-03-10 07:47:25 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-04-12 19:08:53 +0300 |
commit | 93272beafa9d9a5933590c90d2fa525e86e67032 (patch) | |
tree | 87b3eed7ab459a8be9fb45cc4d5391ff450706d3 /fs/jbd2 | |
parent | d2a70d6055c5da54d3f45805a19c37a693acd07f (diff) | |
download | linux-93272beafa9d9a5933590c90d2fa525e86e67032.tar.xz |
jbd2: fix FS corruption possibility in jbd2_journal_destroy() on umount path
commit c0a2ad9b50dd80eeccd73d9ff962234590d5ec93 upstream.
On umount path, jbd2_journal_destroy() writes latest transaction ID
(->j_tail_sequence) to be used at next mount.
The bug is that ->j_tail_sequence is not holding latest transaction ID
in some cases. So, at next mount, there is chance to conflict with
remaining (not overwritten yet) transactions.
mount (id=10)
write transaction (id=11)
write transaction (id=12)
umount (id=10) <= the bug doesn't write latest ID
mount (id=10)
write transaction (id=11)
crash
mount
[recovery process]
transaction (id=11)
transaction (id=12) <= valid transaction ID, but old commit
must not replay
Like above, this bug become the cause of recovery failure, or FS
corruption.
So why ->j_tail_sequence doesn't point latest ID?
Because if checkpoint transactions was reclaimed by memory pressure
(i.e. bdev_try_to_free_page()), then ->j_tail_sequence is not updated.
(And another case is, __jbd2_journal_clean_checkpoint_list() is called
with empty transaction.)
So in above cases, ->j_tail_sequence is not pointing latest
transaction ID at umount path. Plus, REQ_FLUSH for checkpoint is not
done too.
So, to fix this problem with minimum changes, this patch updates
->j_tail_sequence, and issue REQ_FLUSH. (With more complex changes,
some optimizations would be possible to avoid unnecessary REQ_FLUSH
for example though.)
BTW,
journal->j_tail_sequence =
++journal->j_transaction_sequence;
Increment of ->j_transaction_sequence seems to be unnecessary, but
ext3 does this.
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/jbd2')
-rw-r--r-- | fs/jbd2/journal.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index 81e622681c82..624a57a9c4aa 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -1408,11 +1408,12 @@ out: /** * jbd2_mark_journal_empty() - Mark on disk journal as empty. * @journal: The journal to update. + * @write_op: With which operation should we write the journal sb * * Update a journal's dynamic superblock fields to show that journal is empty. * Write updated superblock to disk waiting for IO to complete. */ -static void jbd2_mark_journal_empty(journal_t *journal) +static void jbd2_mark_journal_empty(journal_t *journal, int write_op) { journal_superblock_t *sb = journal->j_superblock; @@ -1430,7 +1431,7 @@ static void jbd2_mark_journal_empty(journal_t *journal) sb->s_start = cpu_to_be32(0); read_unlock(&journal->j_state_lock); - jbd2_write_superblock(journal, WRITE_FUA); + jbd2_write_superblock(journal, write_op); /* Log is no longer empty */ write_lock(&journal->j_state_lock); @@ -1716,7 +1717,13 @@ int jbd2_journal_destroy(journal_t *journal) if (journal->j_sb_buffer) { if (!is_journal_aborted(journal)) { mutex_lock(&journal->j_checkpoint_mutex); - jbd2_mark_journal_empty(journal); + + write_lock(&journal->j_state_lock); + journal->j_tail_sequence = + ++journal->j_transaction_sequence; + write_unlock(&journal->j_state_lock); + + jbd2_mark_journal_empty(journal, WRITE_FLUSH_FUA); mutex_unlock(&journal->j_checkpoint_mutex); } else err = -EIO; @@ -1975,7 +1982,7 @@ int jbd2_journal_flush(journal_t *journal) * the magic code for a fully-recovered superblock. Any future * commits of data to the journal will restore the current * s_start value. */ - jbd2_mark_journal_empty(journal); + jbd2_mark_journal_empty(journal, WRITE_FUA); mutex_unlock(&journal->j_checkpoint_mutex); write_lock(&journal->j_state_lock); J_ASSERT(!journal->j_running_transaction); @@ -2021,7 +2028,7 @@ int jbd2_journal_wipe(journal_t *journal, int write) if (write) { /* Lock to make assertions happy... */ mutex_lock(&journal->j_checkpoint_mutex); - jbd2_mark_journal_empty(journal); + jbd2_mark_journal_empty(journal, WRITE_FUA); mutex_unlock(&journal->j_checkpoint_mutex); } |