Re: [PATCH 07/10] btrfs: rename btrfs_check_shared() to a more descriptive name

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

On 2022/9/1 21:18, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
>
> The function btrfs_check_shared() is supposed to be used to check if a
> data extent is shared, but its name is too generic, may easily cause
> confusion in the sense that it may be used for metadata extents.
>
> So rename it to btrfs_is_data_extent_shared(), which will also make it
> less confusing after the next change that adds a backref lookup cache for
> the b+tree nodes that lead to the leaf that contains the file extent item
> that points to the target data extent.
>
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Reviewed-by: Qu Wenruo <wqu@suse.com>

Thanks,
Qu

> ---
>   fs/btrfs/backref.c   | 8 ++++----
>   fs/btrfs/backref.h   | 4 ++--
>   fs/btrfs/extent_io.c | 5 +++--
>   3 files changed, 9 insertions(+), 8 deletions(-)
>
> diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
> index d385357e19b6..e2ac10a695b6 100644
> --- a/fs/btrfs/backref.c
> +++ b/fs/btrfs/backref.c
> @@ -1512,7 +1512,7 @@ int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
>   }
>
>   /**
> - * Check if an extent is shared or not
> + * Check if a data extent is shared or not.
>    *
>    * @root:   root inode belongs to
>    * @inum:   inode number of the inode whose extent we are checking
> @@ -1520,7 +1520,7 @@ int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
>    * @roots:  list of roots this extent is shared among
>    * @tmp:    temporary list used for iteration
>    *
> - * btrfs_check_shared uses the backref walking code but will short
> + * btrfs_is_data_extent_shared uses the backref walking code but will short
>    * circuit as soon as it finds a root or inode that doesn't match the
>    * one passed in. This provides a significant performance benefit for
>    * callers (such as fiemap) which want to know whether the extent is
> @@ -1531,8 +1531,8 @@ int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
>    *
>    * Return: 0 if extent is not shared, 1 if it is shared, < 0 on error.
>    */
> -int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr,
> -		struct ulist *roots, struct ulist *tmp)
> +int btrfs_is_data_extent_shared(struct btrfs_root *root, u64 inum, u64 bytenr,
> +				struct ulist *roots, struct ulist *tmp)
>   {
>   	struct btrfs_fs_info *fs_info = root->fs_info;
>   	struct btrfs_trans_handle *trans;
> diff --git a/fs/btrfs/backref.h b/fs/btrfs/backref.h
> index 2759de7d324c..08354394b1bb 100644
> --- a/fs/btrfs/backref.h
> +++ b/fs/btrfs/backref.h
> @@ -62,8 +62,8 @@ int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
>   			  u64 start_off, struct btrfs_path *path,
>   			  struct btrfs_inode_extref **ret_extref,
>   			  u64 *found_off);
> -int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr,
> -		struct ulist *roots, struct ulist *tmp_ulist);
> +int btrfs_is_data_extent_shared(struct btrfs_root *root, u64 inum, u64 bytenr,
> +				struct ulist *roots, struct ulist *tmp);
>
>   int __init btrfs_prelim_ref_init(void);
>   void __cold btrfs_prelim_ref_exit(void);
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index 1260038eb47d..a47710516ecf 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -5656,8 +5656,9 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
>   			 * then we're just getting a count and we can skip the
>   			 * lookup stuff.
>   			 */
> -			ret = btrfs_check_shared(root, btrfs_ino(inode),
> -						 bytenr, roots, tmp_ulist);
> +			ret = btrfs_is_data_extent_shared(root, btrfs_ino(inode),
> +							  bytenr, roots,
> +							  tmp_ulist);
>   			if (ret < 0)
>   				goto out_free;
>   			if (ret)