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

[Jeff Mahoney <jeffm@suse.com>]

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On 3/7/18 3:17 AM, Nikolay Borisov wrote:
> 
> 
> 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.

Yep, it's unused, but that's a different project.  Add
-Wunused-parameter and see what shakes out. :)

>>  {
>>  	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

Yep, and it was in the first chunk.

>> +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.

Ah, yep.  That's the fallout from adding const, reformatting, and
removing it.  I'll just skip it entirely.

-Jeff

-- 
Jeff Mahoney
SUSE Labs


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