On Wed, Oct 12, 2016 at 04:58:35PM -0600, Andreas Dilger wrote:

On Mar 17, 2015, at 8:08 PM, Taesoo Kim [off-list ref] wrote:

quoted

When 'jh->b_transaction == transaction' (asserted by below)

        J_ASSERT_JH(jh, (jh->b_transaction == transaction || ...

'journal->j_list_lock' will be incorrectly unlocked, since
spin_lock() is called only in the 'if' and 'else-if' blocks but
not in the missing 'else' case, which results in a hang or an oops....

Signed-off-by: Taesoo Kim <redacted>

We've hit this repeatedly on kernels with commit v3.14-rc2-30-g6e4862a
"jbd2: minimize region locked by j_list_lock in journal_get_create_access"
under heavy load and this patch has fixed the problem.

It should also be considered for stable kernels after 3.14.

[I've updated the above commit message slightly to give more details.]

Reviewed-by: Andreas Dilger <redacted>

Thanks, applied.

Apologies, this got lost which is why I hadn't handled it earlier.

	   	    	       	      - Ted