aboutsummaryrefslogtreecommitdiff
path: root/include
diff options
context:
space:
mode:
authorTheodore Ts'o <tytso@mit.edu>2013-04-03 22:02:52 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-05-07 20:33:14 -0700
commitbf170962d68d20f75c1db40c3fb3727c479424e3 (patch)
treecbfec6fec8b8ca71c13d9ac56201b526ea7e7661 /include
parentb10a905466923f7b937d3f85237095afc2a7f6bf (diff)
ext4/jbd2: don't wait (forever) for stale tid caused by wraparound
commit d76a3a77113db020d9bb1e894822869410450bd9 upstream. 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 deeeaf13 "jbd2: fix fsync() tid wraparound bug", later modified by commit e7b04ac0 "jbd2: don't wake kjournald unnecessarily", attempted to fix this problem, but it only avoided kjournald spinning forever by fixing the logic in jbd2_log_start_commit(). Unfortunately, in the codepaths in fs/ext4/fsync.c and fs/ext4/inode.c that might call jbd2_log_start_commit() with a stale tid, those functions will subsequently call jbd2_log_wait_commit() with the same stale tid, and then wait for a very long time. To fix this, we replace the calls to jbd2_log_start_commit() and jbd2_log_wait_commit() with a call to a new function, jbd2_complete_transaction(), which will correctly handle stale tid's. As a bonus, jbd2_complete_transaction() will avoid locking j_state_lock for writing unless a commit needs to be started. This should have a small (but probably not measurable) improvement for ext4's scalability. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reported-by: Ben Hutchings <ben@decadent.org.uk> Reported-by: George Barnett <gbarnett@atlassian.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/jbd2.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 50e5a5e6a71..f0289754b46 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1200,6 +1200,7 @@ int __jbd2_log_start_commit(journal_t *journal, tid_t tid);
int jbd2_journal_start_commit(journal_t *journal, tid_t *tid);
int jbd2_journal_force_commit_nested(journal_t *journal);
int jbd2_log_wait_commit(journal_t *journal, tid_t tid);
+int jbd2_complete_transaction(journal_t *journal, tid_t tid);
int jbd2_log_do_checkpoint(journal_t *journal);
int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid);