jbd: protect all log tail updates with j_checkpoint_mutex
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 journal_commit_transaction() and journal_flush() can really race
with other log tail updates (e.g. someone doing journal_flush() with someone
running cleanup_journal_tail()). So protect all log tail updates with
j_checkpoint_mutex.
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/jbd/journal.c b/fs/jbd/journal.c
index 44c104a..b29c767 100644
--- a/fs/jbd/journal.c
+++ b/fs/jbd/journal.c
@@ -936,8 +936,11 @@
journal->j_errno);
journal->j_flags |= JFS_FLUSHED;
} else {
+ /* Lock here to make assertions happy... */
+ mutex_lock(&journal->j_checkpoint_mutex);
/* Add the dynamic fields and write it to disk. */
journal_update_sb_log_tail(journal);
+ mutex_unlock(&journal->j_checkpoint_mutex);
}
return journal_start_thread(journal);
}
@@ -1061,6 +1064,7 @@
{
journal_superblock_t *sb = journal->j_superblock;
+ BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
spin_lock(&journal->j_state_lock);
jbd_debug(1,"JBD: updating superblock (start %u, seq %d, errno %d)\n",
journal->j_tail, journal->j_tail_sequence, journal->j_errno);
@@ -1089,6 +1093,7 @@
{
journal_superblock_t *sb = journal->j_superblock;
+ BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
spin_lock(&journal->j_state_lock);
jbd_debug(1, "JBD: Marking journal as empty (seq %d)\n",
journal->j_tail_sequence);
@@ -1293,6 +1298,8 @@
/* Force any old transactions to disk */
+ /* We cannot race with anybody but must keep assertions happy */
+ mutex_lock(&journal->j_checkpoint_mutex);
/* Totally anal locking here... */
spin_lock(&journal->j_list_lock);
while (journal->j_checkpoint_transactions != NULL) {
@@ -1315,6 +1322,7 @@
err = -EIO;
brelse(journal->j_sb_buffer);
}
+ mutex_unlock(&journal->j_checkpoint_mutex);
if (journal->j_inode)
iput(journal->j_inode);
@@ -1528,6 +1536,7 @@
if (is_journal_aborted(journal))
return -EIO;
+ mutex_lock(&journal->j_checkpoint_mutex);
cleanup_journal_tail(journal);
/* Finally, mark the journal as really needing no recovery.
@@ -1536,6 +1545,7 @@
* commits of data to the journal will restore the current
* s_start value. */
mark_journal_empty(journal);
+ mutex_unlock(&journal->j_checkpoint_mutex);
spin_lock(&journal->j_state_lock);
J_ASSERT(!journal->j_running_transaction);
J_ASSERT(!journal->j_committing_transaction);
@@ -1576,8 +1586,12 @@
write ? "Clearing" : "Ignoring");
err = journal_skip_recovery(journal);
- if (write)
+ if (write) {
+ /* Lock to make assertions happy... */
+ mutex_lock(&journal->j_checkpoint_mutex);
mark_journal_empty(journal);
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ }
no_recovery:
return err;