tree c1a6af07da3184f5785a62062510ac8e86b8050a
parent e9e3bcecf44c04b9e6b505fd8e2eb9cea58fb94d
author Theodore Ts'o <tytso@mit.edu> 1297516704 -0500
committer Theodore Ts'o <tytso@mit.edu> 1297516704 -0500

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" <tytso@mit.edu>