jbd2: 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 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@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 6e75fbd..fc5f2ac 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1123,8 +1123,11 @@
journal->j_errno);
journal->j_flags |= JBD2_FLUSHED;
} else {
+ /* Lock here to make assertions happy... */
+ mutex_lock(&journal->j_checkpoint_mutex);
/* Add the dynamic fields and write it to disk. */
jbd2_journal_update_sb_log_tail(journal);
+ mutex_unlock(&journal->j_checkpoint_mutex);
}
return jbd2_journal_start_thread(journal);
}
@@ -1173,6 +1176,7 @@
{
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: updating superblock (start %ld, seq %d)\n",
journal->j_tail, journal->j_tail_sequence);
@@ -1201,6 +1205,7 @@
{
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);
@@ -1434,9 +1439,11 @@
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);
}
@@ -1630,6 +1637,7 @@
if (is_journal_aborted(journal))
return -EIO;
+ mutex_lock(&journal->j_checkpoint_mutex);
jbd2_cleanup_journal_tail(journal);
/* Finally, mark the journal as really needing no recovery.
@@ -1638,6 +1646,7 @@
* 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);
@@ -1678,8 +1687,12 @@
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;