Re: [PATCH 3/8] btrfs-progs: constify pathnames passed as arguments

[Nikolay Borisov <nborisov@suse.com>]

On  2.03.2018 20:46, jeffm@suse.com wrote:
> From: Jeff Mahoney <jeffm@suse.com>
> 
> It's unlikely we're going to modify a pathname argument, so codify that
> and use const.
> 
> Signed-off-by: Jeff Mahoney <jeffm@suse.com>
> ---
>  chunk-recover.c | 4 ++--
>  cmds-device.c   | 2 +-
>  cmds-fi-usage.c | 6 +++---
>  cmds-rescue.c   | 4 ++--
>  send-utils.c    | 4 ++--
>  5 files changed, 10 insertions(+), 10 deletions(-)
> 
> diff --git a/chunk-recover.c b/chunk-recover.c
> index 705bcf52..1d30db51 100644
> --- a/chunk-recover.c
> +++ b/chunk-recover.c
> @@ -1492,7 +1492,7 @@ out:
>  	return ERR_PTR(ret);
>  }
>  
> -static int recover_prepare(struct recover_control *rc, char *path)
> +static int recover_prepare(struct recover_control *rc, const char *path)
>  {
>  	int ret;
>  	int fd;
> @@ -2296,7 +2296,7 @@ static void validate_rebuild_chunks(struct recover_control *rc)
>  /*
>   * Return 0 when successful, < 0 on error and > 0 if aborted by user
>   */
> -int btrfs_recover_chunk_tree(char *path, int verbose, int yes)
> +int btrfs_recover_chunk_tree(const char *path, int verbose, int yes)
>  {
>  	int ret = 0;
>  	struct btrfs_root *root = NULL;
> diff --git a/cmds-device.c b/cmds-device.c
> index 86459d1b..a49c9d9d 100644
> --- a/cmds-device.c
> +++ b/cmds-device.c
> @@ -526,7 +526,7 @@ static const char * const cmd_device_usage_usage[] = {
>  	NULL
>  };
>  
> -static int _cmd_device_usage(int fd, char *path, unsigned unit_mode)
> +static int _cmd_device_usage(int fd, const char *path, unsigned unit_mode)

Actually the path parameter is not used in this function at all, I'd say
just remove it.

>  {
>  	int i;
>  	int ret = 0;> diff --git a/cmds-fi-usage.c b/cmds-fi-usage.c
> index de7ad668..9a1c76ab 100644
> --- a/cmds-fi-usage.c
> +++ b/cmds-fi-usage.c
> @@ -227,7 +227,7 @@ static int cmp_btrfs_ioctl_space_info(const void *a, const void *b)
>  /*
>   * This function load all the information about the space usage
>   */
> -static struct btrfs_ioctl_space_args *load_space_info(int fd, char *path)
> +static struct btrfs_ioctl_space_args *load_space_info(int fd, const char *path)
>  {
>  	struct btrfs_ioctl_space_args *sargs = NULL, *sargs_orig = NULL;
>  	int ret, count;
> @@ -305,7 +305,7 @@ static void get_raid56_used(struct chunk_info *chunks, int chunkcount,
>  #define	MIN_UNALOCATED_THRESH	SZ_16M
>  static int print_filesystem_usage_overall(int fd, struct chunk_info *chunkinfo,
>  		int chunkcount, struct device_info *devinfo, int devcount,
> -		char *path, unsigned unit_mode)
> +		const char *path, unsigned unit_mode)
>  {
>  	struct btrfs_ioctl_space_args *sargs = NULL;
>  	int i;
> @@ -931,7 +931,7 @@ static void _cmd_filesystem_usage_linear(unsigned unit_mode,
>  static int print_filesystem_usage_by_chunk(int fd,
>  		struct chunk_info *chunkinfo, int chunkcount,
>  		struct device_info *devinfo, int devcount,
> -		char *path, unsigned unit_mode, int tabular)
> +		const char *path, unsigned unit_mode, int tabular)
>  {
>  	struct btrfs_ioctl_space_args *sargs;
>  	int ret = 0;
> diff --git a/cmds-rescue.c b/cmds-rescue.c
> index c40088ad..c61145bc 100644
> --- a/cmds-rescue.c
> +++ b/cmds-rescue.c
> @@ -32,8 +32,8 @@ static const char * const rescue_cmd_group_usage[] = {
>  	NULL
>  };
>  
> -int btrfs_recover_chunk_tree(char *path, int verbose, int yes);
> -int btrfs_recover_superblocks(char *path, int verbose, int yes);
> +int btrfs_recover_chunk_tree(const char *path, int verbose, int yes);

That path argument is being passed to recover_prepare which can alo use
a const to its path parameter

> +int btrfs_recover_superblocks(const char *path, int verbose, int yes);
>  
>  static const char * const cmd_rescue_chunk_recover_usage[] = {
>  	"btrfs rescue chunk-recover [options] <device>",
> diff --git a/send-utils.c b/send-utils.c
> index b5289e76..8ce94de1 100644
> --- a/send-utils.c
> +++ b/send-utils.c
> @@ -28,8 +28,8 @@
>  #include "ioctl.h"
>  #include "btrfs-list.h"
>  
> -static int btrfs_subvolid_resolve_sub(int fd, char *path, size_t *path_len,
> -				      u64 subvol_id);
> +static int btrfs_subvolid_resolve_sub(int fd, char *path,
> +				      size_t *path_len, u64 subvol_id);

This seems like an unrelated change. As a matter of fact
btrfs_subvolid_resolve_sub is used only by btrfs_subvolid_resolve. So if
you move the latter after the former then you can drop the declaration
at the beginning of the file altogether.

>  
>  static int btrfs_get_root_id_by_sub_path(int mnt_fd, const char *sub_path,
>  					 u64 *root_id)
>