Re: [PATCH v2 1/2] fiemap: Factor out actual fiemap call code

[Nikolay Borisov <nborisov@suse.com>]

On 31.10.2017 22:29, Darrick J. Wong wrote:
>> Subject: Re: [PATCH v2 1/2] fiemap: Factor out actual fiemap call code
> 
> I thought this was v3....
> 
> On Tue, Oct 31, 2017 at 04:10:10PM +0200, Nikolay Borisov wrote:
>> This will be needed to in a subsequent patch to avoid code duplication
>>
>> Signed-off-by: Nikolay Borisov <nborisov@suse.com>
>> ---
>> v2:
>>  * Incorporated Daricks feedback - removed variables which weren't introduced
>>  until the next patch as a result the build with this patch was broken. This is 
>>  fixed now
>>  io/fiemap.c | 39 ++++++++++++++++++++++++++++-----------
>>  1 file changed, 28 insertions(+), 11 deletions(-)
>>
>> diff --git a/io/fiemap.c b/io/fiemap.c
>> index e6fd66da753d..08391f69d9bd 100644
>> --- a/io/fiemap.c
>> +++ b/io/fiemap.c
>> @@ -211,6 +211,31 @@ calc_print_format(
>>  	}
>>  }
>>  
>> +static int
>> +__fiemap(
>> +	 struct fiemap * fiemap,
> 
> 	struct fiemap	*fiemap,
> 
>> +	 int		 mapsize,
>> +	 __u32		 flags,
>> +	 __u64		 start,
>> +	 __u64		 length) {
>> +
>> +	int ret;
> 
> 	int		ret;
> 
> (Yeah, I know...)
> 
>> +
>> +	memset(fiemap, 0, mapsize);
>> +	fiemap->fm_flags = flags;
>> +	fiemap->fm_start = start;
>> +	fiemap->fm_length = length;
>> +	fiemap->fm_extent_count = EXTENT_BATCH;
> 
> It's odd that we pass in both the struct* and its initializers here, but
> we still have to have a way to pass fm_flags and fm_mapped_extents back
> to the __fiemap() caller.
> 
> (TBH I'm wondering if this patch is necessary...)

Well,

I'd rather have this function and make the final hole handling in the
next one being a bit more clear, than duplicating the setup + ioctl
statements :)

> 
> --D
> 
>> +	ret = ioctl(file->fd, FS_IOC_FIEMAP, fiemap);
>> +	if (ret < 0) {
>> +	        fprintf(stderr, "%s: ioctl(FS_IOC_FIEMAP) [\"%s\"]: "
>> +	                "%s\n", progname, file->name, strerror(errno));
>> +	        return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>>  int
>>  fiemap_f(
>>  	int		argc,
>> @@ -266,19 +291,11 @@ fiemap_f(
>>  
>>  	while (!last && (cur_extent != max_extents)) {
>>  
>> -		memset(fiemap, 0, map_size);
>> -		fiemap->fm_flags = fiemap_flags;
>> -		fiemap->fm_start = last_logical;
>> -		fiemap->fm_length = -1LL;
>> -		fiemap->fm_extent_count = EXTENT_BATCH;
>> -
>> -		ret = ioctl(file->fd, FS_IOC_FIEMAP, (unsigned long)fiemap);
>> +		ret = __fiemap(fiemap, map_size, fiemap_flags, last_logical,
>> +			       -1LL);
>>  		if (ret < 0) {
>> -			fprintf(stderr, "%s: ioctl(FS_IOC_FIEMAP) [\"%s\"]: "
>> -				"%s\n", progname, file->name, strerror(errno));
>> -			free(fiemap);
>>  			exitcode = 1;
>> -			return 0;
>> +			goto out;
>>  		}
>>  
>>  		/* No more extents to map, exit */
>> -- 
>> 2.7.4
>>
>> --
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>