From 43e8149d0401067293a8a5a8b85f4c34560e2a9e Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Mon, 30 Mar 2015 18:26:47 +0100 Subject: [PATCH] Btrfs: fix inode eviction infinite loop after extent_same ioctl [ Upstream commit HEAD ] commit 113e8283869b9855c8b999796aadd506bbac155f upstream. If we pass a length of 0 to the extent_same ioctl, we end up locking an extent range with a start offset greater then its end offset (if the destination file's offset is greater than zero). This results in a warning from extent_io.c:insert_state through the following call chain: btrfs_extent_same() btrfs_double_lock() lock_extent_range() lock_extent(inode->io_tree, offset, offset + len - 1) lock_extent_bits() __set_extent_bit() insert_state() --> WARN_ON(end < start) This leads to an infinite loop when evicting the inode. This is the same problem that my previous patch titled "Btrfs: fix inode eviction infinite loop after cloning into it" addressed but for the extent_same ioctl instead of the clone ioctl. Signed-off-by: Filipe Manana Reviewed-by: Omar Sandoval Signed-off-by: Chris Mason Signed-off-by: Greg Kroah-Hartman (cherry picked from commit 9dc106617d5669a6f8d86e08f620dc2fb0413e21) Signed-off-by: Sasha Levin --- fs/btrfs/ioctl.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 96ea36fedf1d5..5c414fe7f9be4 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -2925,6 +2925,9 @@ static int btrfs_extent_same(struct inode *src, u64 loff, u64 len, if (src == dst) return -EINVAL; + if (len == 0) + return 0; + btrfs_double_lock(src, loff, dst, dst_loff, len); ret = extent_same_check_offsets(src, loff, len); -- 2.47.3