From e44718318004a5618d1dfe2d080e2862532d8e5f Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sat, 12 Feb 2011 08:18:24 -0500 Subject: jbd2: call __jbd2_log_start_commit with j_state_lock write locked On an SMP ARM system running ext4, I've received a report that the first J_ASSERT in jbd2_journal_commit_transaction has been triggering: J_ASSERT(journal->j_running_transaction != NULL); While investigating possible causes for this problem, I noticed that __jbd2_log_start_commit() is getting called with j_state_lock only read-locked, in spite of the fact that it's possible for it might j_commit_request. Fix this by grabbing the necessary information so we can test to see if we need to start a new transaction before dropping the read lock, and then calling jbd2_log_start_commit() which will grab the write lock. Signed-off-by: "Theodore Ts'o" --- fs/jbd2/journal.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'fs/jbd2/journal.c') diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index 9e4686900f1..97e73469b2c 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -473,7 +473,8 @@ int __jbd2_log_space_left(journal_t *journal) } /* - * Called under j_state_lock. Returns true if a transaction commit was started. + * Called with j_state_lock locked for writing. + * Returns true if a transaction commit was started. */ int __jbd2_log_start_commit(journal_t *journal, tid_t target) { @@ -520,11 +521,13 @@ int jbd2_journal_force_commit_nested(journal_t *journal) { transaction_t *transaction = NULL; tid_t tid; + int need_to_start = 0; read_lock(&journal->j_state_lock); if (journal->j_running_transaction && !current->journal_info) { transaction = journal->j_running_transaction; - __jbd2_log_start_commit(journal, transaction->t_tid); + if (!tid_geq(journal->j_commit_request, transaction->t_tid)) + need_to_start = 1; } else if (journal->j_committing_transaction) transaction = journal->j_committing_transaction; @@ -535,6 +538,8 @@ int jbd2_journal_force_commit_nested(journal_t *journal) tid = transaction->t_tid; read_unlock(&journal->j_state_lock); + if (need_to_start) + jbd2_log_start_commit(journal, tid); jbd2_log_wait_commit(journal, tid); return 1; } -- cgit v1.2.3-70-g09d2