From: Theodore Ts'o <tytso@mit.edu>
Date: Sat, 12 Feb 2011 13:18:24 +0000 (-0500)
Subject: jbd2: call __jbd2_log_start_commit with j_state_lock write locked
X-Git-Tag: v2.6.38-rc5~24^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e44718318004a5618d1dfe2d080e2862532d8e5f;p=pandora-kernel.git

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>
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