From: Michal Hocko <mhocko@xxxxxxxx> 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@xxxxxxx> Reviewed-by: Jan Kara <jack@xxxxxxx> Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> --- fs/jbd2/journal.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index a1a359bfcc9c..78433ce1db40 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -43,6 +43,7 @@ #include <linux/backing-dev.h> #include <linux/bitops.h> #include <linux/ratelimit.h> +#include <linux/sched/mm.h> #define CREATE_TRACE_POINTS #include <trace/events/jbd2.h> @@ -206,6 +207,13 @@ 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
