fs: btrfs: volumes.c: Fix for possible null pointer dereference

commit 8321cf2596d283821acc466377c2b85bcd3422b7 upstream.

There is otherwise a risk of a possible null pointer dereference.

Was largely found by using a static code analysis program called cppcheck.

Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 254fed2bbb52d457a814fb7cdf562a91e891f72f..57b699410fb87f8d2a4e55a1a6c7f31791681630 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1690,11 +1690,12 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
                struct btrfs_fs_devices *fs_devices;
                fs_devices = root->fs_info->fs_devices;
                while (fs_devices) {
-                       if (fs_devices->seed == cur_devices)
+                       if (fs_devices->seed == cur_devices) {
+                               fs_devices->seed = cur_devices->seed;
                                break;
+                       }
                        fs_devices = fs_devices->seed;
                }
-               fs_devices->seed = cur_devices->seed;
                cur_devices->seed = NULL;
                lock_chunks(root);
                __btrfs_close_devices(cur_devices);