Commit eb52da3f authored by Michal Hocko's avatar Michal Hocko Committed by Linus Torvalds

jbd2: make the whole kjournald2 kthread NOFS safe

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.

[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20170306131408.9828-8-mhocko@kernel.orgSigned-off-by: default avatarMichal Hocko <mhocko@suse.com>
Suggested-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Chris Mason <clm@fb.com>
Cc: David Sterba <dsterba@suse.cz>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Nikolay Borisov <nborisov@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 81378da6
......@@ -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>
......@@ -205,6 +206,14 @@ static int kjournald2(void *arg)
journal->j_task = current;
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.
*/
......
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