Re: [PATCH 07/11] btrfs: cleanup btrfs_remove_chunk

Nikolay Borisov
2020-08-31T08:43:09Z

On 30.08.20 г. 17:41 ч., Anand Jain wrote:
> In the function btrfs_remove_chunk() remove the local variable
> %fs_devices, instead use the assigned pointer directly.
>
> Signed-off-by: Anand Jain <anand.jain@oracle.com>

So this is minor enough and correct, however, have measured whether
having multiple fs_info::fs_devices:device_list_Mutex derefs results in
slightly (perhaps negligible) increase in code size.

In any case the code is correct, so:

Reviewed-by: Nikolay Borisov <nborisov@suse.com>

> ---
> fs/btrfs/volumes.c | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 7639a048c6cf..3e7a7d94a211 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -2922,7 +2922,6 @@ int btrfs_remove_chunk(struct btrfs_trans_handle *trans, u64 chunk_offset)
> struct map_lookup *map;
> u64 dev_extent_len = 0;
> int i, ret = 0;
> - struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
>
> em = btrfs_get_chunk_map(fs_info, chunk_offset, 1);
> if (IS_ERR(em)) {
> @@ -2944,14 +2943,14 @@ int btrfs_remove_chunk(struct btrfs_trans_handle *trans, u64 chunk_offset)
> * a device replace operation that replaces the device object associated
> * with map stripes (dev-replace.c:btrfs_dev_replace_finishing()).
> */
> - mutex_lock(&fs_devices->device_list_mutex);
> + mutex_lock(&fs_info->fs_devices->device_list_mutex);
> for (i = 0; i < map->num_stripes; i++) {
> struct btrfs_device *device = map->stripes[i].dev;
> ret = btrfs_free_dev_extent(trans, device,
> map->stripes[i].physical,
> &dev_extent_len);
> if (ret) {
> - mutex_unlock(&fs_devices->device_list_mutex);
> + mutex_unlock(&fs_info->fs_devices->device_list_mutex);
> btrfs_abort_transaction(trans, ret);
> goto out;
> }
> @@ -2967,12 +2966,12 @@ int btrfs_remove_chunk(struct btrfs_trans_handle *trans, u64 chunk_offset)
>
> ret = btrfs_update_device(trans, device);
> if (ret) {
> - mutex_unlock(&fs_devices->device_list_mutex);
> + mutex_unlock(&fs_info->fs_devices->device_list_mutex);
> btrfs_abort_transaction(trans, ret);
> goto out;
> }
> }
> - mutex_unlock(&fs_devices->device_list_mutex);
> + mutex_unlock(&fs_info->fs_devices->device_list_mutex);
>
> ret = btrfs_free_chunk(trans, chunk_offset);
> if (ret) {
>