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

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>

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 7d725a9ce670..ffeed6d6326f 100644
--- 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);