From 5e6ecb362bd5950a3d8ce19c32829e4f8c7917d9 Mon Sep 17 00:00:00 2001 From: Filipe Manana <fdmanana@suse.com> Date: Tue, 13 Oct 2015 16:36:09 +0100 Subject: Btrfs: fix double range unlock of hole region when reading page If when reading a page we find a hole and our caller had already locked the range (bio flags has the bit EXTENT_BIO_PARENT_LOCKED set), we end up unlocking the hole's range and then later our caller unlocks it again, which might have already been locked by some other task once the first unlock happened. Currently this can only happen during a call to the extent_same ioctl, as it's the only caller of __do_readpage() that sets the bit EXTENT_BIO_PARENT_LOCKED for bio flags. Fix this by leaving the unlock exclusively to the caller. Signed-off-by: Filipe Manana <fdmanana@suse.com> --- fs/btrfs/extent_io.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'fs') diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index ecb1204468c3..6e6df34d74f0 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3070,8 +3070,12 @@ static int __do_readpage(struct extent_io_tree *tree, set_extent_uptodate(tree, cur, cur + iosize - 1, &cached, GFP_NOFS); - unlock_extent_cached(tree, cur, cur + iosize - 1, - &cached, GFP_NOFS); + if (parent_locked) + free_extent_state(cached); + else + unlock_extent_cached(tree, cur, + cur + iosize - 1, + &cached, GFP_NOFS); cur = cur + iosize; pg_offset += iosize; continue; -- cgit