3.2.72-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Jan Kara <jack@xxxxxxx>
commit a78bb11d7acd525623c6a0c2ff4e213d527573fa upstream.
There are some log tail updates that are not protected by j_checkpoint_mutex.
Some of these are harmless because they happen during startup or shutdown but
updates in jbd2_journal_commit_transaction() and jbd2_journal_flush() can
really race with other log tail updates (e.g. someone doing
jbd2_journal_flush() with someone running jbd2_cleanup_journal_tail()). So
protect all log tail updates with j_checkpoint_mutex.
Signed-off-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
[bwh: Backported to 3.2:
- Adjust context
- Add unlock on the error path in jbd2_journal_flush()]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Cc: Bartosz Kwitniewski <zerg2000@xxxxxxxxxxxxx>
---
fs/jbd2/commit.c | 2 ++
fs/jbd2/journal.c | 19 ++++++++++++++++---
2 files changed, 18 insertions(+), 3 deletions(-)
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -340,6 +340,7 @@ void jbd2_journal_commit_transaction(jou
/* Do we need to erase the effects of a prior jbd2_journal_flush? */
if (journal->j_flags & JBD2_FLUSHED) {
jbd_debug(3, "super block updated\n");
+ mutex_lock(&journal->j_checkpoint_mutex);
/*
* We hold j_checkpoint_mutex so tail cannot change under us.
* We don't need any special data guarantees for writing sb
@@ -350,6 +351,7 @@ void jbd2_journal_commit_transaction(jou
journal->j_tail_sequence,
journal->j_tail,
WRITE_SYNC);
+ mutex_unlock(&journal->j_checkpoint_mutex);
} else {
jbd_debug(3, "superblock not updated\n");
}
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1242,6 +1242,8 @@ static int journal_reset(journal_t *jour
journal->j_errno);
journal->j_flags |= JBD2_FLUSHED;
} else {
+ /* Lock here to make assertions happy... */
+ mutex_lock(&journal->j_checkpoint_mutex);
/*
* Update log tail information. We use WRITE_FUA since new
* transaction will start reusing journal space and so we
@@ -1252,6 +1254,7 @@ static int journal_reset(journal_t *jour
journal->j_tail_sequence,
journal->j_tail,
WRITE_FUA);
+ mutex_unlock(&journal->j_checkpoint_mutex);
}
return jbd2_journal_start_thread(journal);
}
@@ -1314,6 +1317,7 @@ int jbd2_journal_update_sb_log_tail(jour
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",
tail_block, tail_tid);
@@ -1344,6 +1348,7 @@ static void jbd2_mark_journal_empty(jour
{
journal_superblock_t *sb = journal->j_superblock;
+ BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
read_lock(&journal->j_state_lock);
jbd_debug(1, "JBD2: Marking journal as empty (seq %d)\n",
journal->j_tail_sequence);
@@ -1577,9 +1582,11 @@ int jbd2_journal_destroy(journal_t *jour
spin_unlock(&journal->j_list_lock);
if (journal->j_sb_buffer) {
- if (!is_journal_aborted(journal))
+ if (!is_journal_aborted(journal)) {
+ mutex_lock(&journal->j_checkpoint_mutex);
jbd2_mark_journal_empty(journal);
- else
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ } else
err = -EIO;
brelse(journal->j_sb_buffer);
}
@@ -1828,10 +1835,13 @@ int jbd2_journal_flush(journal_t *journa
if (is_journal_aborted(journal))
return -EIO;
+ mutex_lock(&journal->j_checkpoint_mutex);
if (!err) {
err = jbd2_cleanup_journal_tail(journal);
- if (err < 0)
+ if (err < 0) {
+ mutex_unlock(&journal->j_checkpoint_mutex);
goto out;
+ }
err = 0;
}
@@ -1841,6 +1851,7 @@ int jbd2_journal_flush(journal_t *journa
* commits of data to the journal will restore the current
* s_start value. */
jbd2_mark_journal_empty(journal);
+ mutex_unlock(&journal->j_checkpoint_mutex);
write_lock(&journal->j_state_lock);
J_ASSERT(!journal->j_running_transaction);
J_ASSERT(!journal->j_committing_transaction);
@@ -1882,8 +1893,12 @@ int jbd2_journal_wipe(journal_t *journal
write ? "Clearing" : "Ignoring");
err = jbd2_journal_skip_recovery(journal);
- if (write)
+ if (write) {
+ /* Lock to make assertions happy... */
+ mutex_lock(&journal->j_checkpoint_mutex);
jbd2_mark_journal_empty(journal);
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ }
no_recovery:
return err;
--
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