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Commit e678a4f0 authored by Jan Kara's avatar Jan Kara
Browse files

jbd: don't wait (forever) for stale tid caused by wraparound 



In the case where an inode has a very stale transaction id (tid) in
i_datasync_tid or i_sync_tid, it's possible that after a very large
(2**31) number of transactions, that the tid number space might wrap,
causing tid_geq()'s calculations to fail.

Commit d9b01934 "jbd: fix fsync() tid wraparound bug" attempted to fix
this problem, but it only avoided kjournald spinning forever by fixing
the logic in jbd_log_start_commit().

Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent e6436921

fs/jbd/journal.c

+11 −0
Original line number Diff line number Diff line
@@ -564,6 +564,16 @@ int log_wait_commit(journal_t *journal, tid_t tid) 
	spin_unlock(&journal->j_state_lock);

#endif

	spin_lock(&journal->j_state_lock);

	/*

	 * Not running or committing trans? Must be already committed. This

	 * saves us from waiting for a *long* time when tid overflows.

	 */

	if (!((journal->j_running_transaction &&

	       journal->j_running_transaction->t_tid == tid) ||

	      (journal->j_committing_transaction &&

	       journal->j_committing_transaction->t_tid == tid)))

		goto out_unlock;



	if (!tid_geq(journal->j_commit_waited, tid))

		journal->j_commit_waited = tid;

	while (tid_gt(tid, journal->j_commit_sequence)) {
@@ -575,6 +585,7 @@ int log_wait_commit(journal_t *journal, tid_t tid) 
				!tid_gt(tid, journal->j_commit_sequence));

		spin_lock(&journal->j_state_lock);

	}

out_unlock:

	spin_unlock(&journal->j_state_lock);



	if (unlikely(is_journal_aborted(journal))) {