From: Filipe Manana Date: Thu, 14 May 2015 19:41:07 +0000 (+0100) Subject: Btrfs: wake up extent state waiters on unlock through clear_extent_bits X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=0f31871f4411b5c0d42fb4403dec83a21a96100b;p=openwrt%2Fstaging%2Fblogic.git 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 Signed-off-by: Filipe Manana Reviewed-by: Liu Bo Signed-off-by: Chris Mason --- diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index c32d226bfecc..856c2e8ea6ac 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -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,