[PATCH 7/9] jbd2: make the whole kjournald2 kthread NOFS safe
From: Michal Hocko <mhocko@kernel.org>
Date: 2016-12-15 14:07:13
Also in:
ceph-devel, linux-btrfs, linux-f2fs-devel, linux-fsdevel, linux-mm, linux-nfs, linux-xfs, lkml
Subsystem:
filesystems (vfs and infrastructure), journalling layer for block devices (jbd2), the rest · Maintainers:
Alexander Viro, Christian Brauner, "Theodore Ts'o", Jan Kara, Linus Torvalds
From: Michal Hocko <mhocko@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 <jack@suse.cz> Signed-off-by: Michal Hocko <mhocko@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 8ed971eeab44..6dad8c5d6ddf 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);
--
2.10.2
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>