btrfs: add helper function check device delete able

Move the section of the code which performs the check if the device is
indelible, move that into a helper function.

Signed-off-by: Anand Jain <anand.jain@oracle.com>

fs/btrfs/volumes.c

@@ -1860,6 +1860,33 @@ static inline u64 btrfs_num_devices(struct btrfs_fs_info *fs_info)
  return num_devices;
 }
 
+static struct btrfs_device *btrfs_device_delete_able(
+ struct btrfs_fs_info *fs_info,
+ const char *device_path, u64 devid)
+{
+ int ret;
+ struct btrfs_device *device;
+
+ ret = btrfs_check_raid_min_devices(fs_info,
+ btrfs_num_devices(fs_info) - 1);
+ if (ret)
+ return ERR_PTR(ret);
+
+ ret = btrfs_find_device_by_devspec(fs_info, devid, device_path,
+ &device);
+ if (ret)
+ return ERR_PTR(ret);
+
+ if (test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
+ return ERR_PTR(BTRFS_ERROR_DEV_TGT_REPLACE);
+
+ if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state) &&
+ fs_info->fs_devices->rw_devices == 1)
+ return ERR_PTR(BTRFS_ERROR_DEV_ONLY_WRITABLE);
+
+ return device;
+}
+
 int btrfs_rm_device(struct btrfs_fs_info *fs_info, const char *device_path,
  u64 devid)
 {
@@ -1873,25 +1900,9 @@ int btrfs_rm_device(struct btrfs_fs_info *fs_info, const char *device_path,
 
  mutex_lock(&uuid_mutex);
 
- num_devices = btrfs_num_devices(fs_info);
-
- ret = btrfs_check_raid_min_devices(fs_info, num_devices - 1);
- if (ret)
- goto out;
-
- ret = btrfs_find_device_by_devspec(fs_info, devid, device_path,
- &device);
- if (ret)
- goto out;
-
- if (test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) {
- ret = BTRFS_ERROR_DEV_TGT_REPLACE;
- goto out;
- }
-
- if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state) &&
- fs_info->fs_devices->rw_devices == 1) {
- ret = BTRFS_ERROR_DEV_ONLY_WRITABLE;
+ device = btrfs_device_delete_able(fs_info, device_path, devid);
+ if (IS_ERR(device)) {
+ ret = PTR_ERR(device);
  goto out;
  }