btrfs: ioctl: reorder exclusive op check in RM_DEV

Move the op exclusivity check before the other code (same as in
ADD_DEV).

Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 1e8ce52..c81d6da 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2689,32 +2689,31 @@ static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
        if (ret)
                return ret;
 
-       vol_args = memdup_user(arg, sizeof(*vol_args));
-       if (IS_ERR(vol_args)) {
-               ret = PTR_ERR(vol_args);
-               goto err_drop;
-       }
-
-       vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
-
        if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
                        1)) {
                ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
+               goto out_drop_write;
+       }
+
+       vol_args = memdup_user(arg, sizeof(*vol_args));
+       if (IS_ERR(vol_args)) {
+               ret = PTR_ERR(vol_args);
                goto out;
        }
 
+       vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
        mutex_lock(&root->fs_info->volume_mutex);
        ret = btrfs_rm_device(root, vol_args->name);
        mutex_unlock(&root->fs_info->volume_mutex);
-       atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
 
        if (!ret)
                btrfs_info(root->fs_info, "disk deleted %s",vol_args->name);
-
-out:
        kfree(vol_args);
-err_drop:
+out:
+       atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
+out_drop_write:
        mnt_drop_write_file(file);
+
        return ret;
 }