| Message ID | 1427736407-29521-1-git-send-email-fdmanana@suse.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On Mon, Mar 30, 2015 at 06:26:47PM +0100, Filipe Manana wrote: > 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. > > CC: <stable@vger.kernel.org> > Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Omar Sandoval <osandov@osandov.com> Reproduced with https://github.com/markfasheh/duperemove/blob/master/btrfs-extent-same.c ./btrfs-extent-same 0 foo 4096 bar 4096
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 4c32350..09a566a 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -2897,6 +2897,9 @@ 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);
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. CC: <stable@vger.kernel.org> Signed-off-by: Filipe Manana <fdmanana@suse.com> --- fs/btrfs/ioctl.c | 3 +++ 1 file changed, 3 insertions(+)