Commit 0f31871f authored May 14, 2015 by Filipe Manana Committed by Chris Mason Jun 03, 2015

Btrfs: wake up extent state waiters on unlock through clear_extent_bits



When we clear an extent state's EXTENT_LOCKED bit with clear_extent_bits()
through free_io_failure(), we weren't waking up any tasks waiting for the
extent's state EXTENT_LOCKED bit, leading to an hang.

So make sure clear_extent_bits() ends up waking up any waiters if the
bit EXTENT_LOCKED is supplied by its callers.

Zygo Blaxell was experiencing such hangs at inode eviction time after
file unlinks. Thanks to him for a set of scripts to reproduce the issue.

Reported-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>

parent c152b63e

fs/btrfs/extent_io.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -1277,7 +1277,12 @@ int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
		int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
		unsigned bits, gfp_t mask)
		{
		return clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask);
		int wake = 0;

		if (bits & EXTENT_LOCKED)
		wake = 1;

		return clear_extent_bit(tree, start, end, bits, wake, 0, NULL, mask);
		}

		int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,

Admin message