From: Michal Hocko <mho...@suse.com>
kjournald2 is central to the transaction commit processing. As such any
potential allocation from this kernel thread has to be GFP_NOFS. Make
sure to mark the whole kernel thread GFP_NOFS by the memalloc_nofs_save.
Suggested-by: Jan Kara <j...@suse.cz>
Reviewed-by: Jan Kara <j...@suse.cz>
Signed-off-by: Michal Hocko <mho...@suse.com>
---
fs/jbd2/journal.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 704139625fbe..662531a70ce1 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -206,6 +206,13 @@ static int kjournald2(void *arg)
wake_up(&journal->j_wait_done_commit);
/*
+ * Make sure that no allocations from this kernel thread will ever
recurse
+ * to the fs layer because we are responsible for the transaction commit
+ * and any fs involvement might get stuck waiting for the trasn. commit.
+ */
+ memalloc_nofs_save();
+
+ /*
* And now, wait forever for commit wakeup events.
*/
write_lock(&journal->j_state_lock);
--
2.11.0
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