Re: [PATCH] btrfs-progs: tidy up cmd_subvol_create() whitespace & returns

[Eric Sandeen <sandeen@redhat.com>]

On 9/3/13 8:13 AM, Wang Shilong wrote:
> Hello Eric,
> 
> Recently, i notice btrfs-progs's magic return value. For example, EACCESS return 12.
> Magic return value is confusing for code reviewers. However,at least we should guarantee
> all these conditions return the same value(for example 12 for this case)
> 
> Or we can change all the magic number to 1. Miao reminded me that
> there may be some applications that have catched and checked these
> magic return values…
> 
> Any ideas about this?

I think that if we want to do anything different from the standard, expected
"return 1 and set errno" then it needs to be a careful design decision, documented,
used consistently, and tested.

As far as I can tell, what is in btrfs-progs today is undocumented,
untested, and only occasionally/randomly used.  Therefore I don't
think it's useful as it stands today, and why I had started removing
them.

-Eric

> Thanks,
> Wang
>> From:
>> Just whitespace fixes, and magical return value removal.
>>
>> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
>> ---
>> cmds-subvolume.c | 18 +++++++++---------
>> 1 file changed, 9 insertions(+), 9 deletions(-)
>>
>> diff --git a/cmds-subvolume.c b/cmds-subvolume.c
>> index 01b982c..a9999ac 100644
>> --- a/cmds-subvolume.c
>> +++ b/cmds-subvolume.c
>> @@ -104,9 +104,9 @@ static int cmd_subvol_create(int argc, char **argv)
>> 	dst = argv[optind];
>>
>> 	res = test_isdir(dst);
>> -	if(res >= 0 ){
>> +	if (res >= 0) {
>> 		fprintf(stderr, "ERROR: '%s' exists\n", dst);
>> -		return 12;
>> +		return 1;
>> 	}
>>
>> 	newname = strdup(dst);
>> @@ -114,24 +114,24 @@ static int cmd_subvol_create(int argc, char **argv)
>> 	dstdir = strdup(dst);
>> 	dstdir = dirname(dstdir);
>>
>> -	if( !strcmp(newname,".") || !strcmp(newname,"..") ||
>> +	if (!strcmp(newname, ".") || !strcmp(newname, "..") ||
>> 	     strchr(newname, '/') ){
>> 		fprintf(stderr, "ERROR: uncorrect subvolume name ('%s')\n",
>> 			newname);
>> -		return 14;
>> +		return 1;
>> 	}
>>
>> 	len = strlen(newname);
>> 	if (len == 0 || len >= BTRFS_VOL_NAME_MAX) {
>> 		fprintf(stderr, "ERROR: subvolume name too long ('%s)\n",
>> 			newname);
>> -		return 14;
>> +		return 1;
>> 	}
>>
>> 	fddst = open_file_or_dir(dstdir);
>> 	if (fddst < 0) {
>> 		fprintf(stderr, "ERROR: can't access to '%s'\n", dstdir);
>> -		return 12;
>> +		return 1;
>> 	}
>>
>> 	printf("Create subvolume '%s/%s'\n", dstdir, newname);
>> @@ -159,10 +159,10 @@ static int cmd_subvol_create(int argc, char **argv)
>> 	close(fddst);
>> 	free(inherit);
>>
>> -	if(res < 0 ){
>> -		fprintf( stderr, "ERROR: cannot create subvolume - %s\n",
>> +	if (res < 0) {
>> +		fprintf(stderr, "ERROR: cannot create subvolume - %s\n",
>> 			strerror(e));
>> -		return 11;
>> +		return 1;
>> 	}
>>
>> 	return 0;
>> -- 
>> 1.7.11.7
>>
>