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>
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index c32d226..856c2e8 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1277,7 +1277,12 @@
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,