From f9b2a5eee5097a8bbb015ea7d6a80e3a5214a3f8 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Mon, 17 Feb 2014 17:30:03 +0100 Subject: [PATCH] fs: jbd2: pull your plug when waiting for space Two cps in parallel managed to stall the the ext4 fs. It seems that journal code is either waiting for locks or sleeping waiting for something to happen. This seems similar to what Mike observed on ext3, here is his description: |With an -rt kernel, and a heavy sync IO load, tasks can jam |up on journal locks without unplugging, which can lead to |terminal IO starvation. Unplug and schedule when waiting |for space. Cc: stable-rt@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior --- fs/jbd2/checkpoint.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c index 7f34f4716165..8c404001d3a1 100644 --- a/fs/jbd2/checkpoint.c +++ b/fs/jbd2/checkpoint.c @@ -125,6 +125,8 @@ void __jbd2_log_wait_for_space(journal_t *journal) if (journal->j_flags & JBD2_ABORT) return; write_unlock(&journal->j_state_lock); + if (current->plug) + io_schedule(); mutex_lock(&journal->j_checkpoint_mutex); /*