Re: [PATCH 2/2, RFC] mkfs.xfs: don't call blkid_get_topology on regular files

[Eric Sandeen <sandeen@sandeen.net>]

On 5/28/14, 12:40 AM, Christoph Hellwig wrote:
> On Tue, May 27, 2014 at 07:15:20PM -0500, Eric Sandeen wrote:
>> If we encounter a target that's really a regular file,
>> even without "-d file..." on the cmdline, call
>> platform_findsizes() instead of blkid_get_topology to
>> try to discover the "sector size" via the fsgeom() call.
>>
>> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
>> ---
>>
>> diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
>> index 37c05a9..74180c9 100644
>> --- a/mkfs/xfs_mkfs.c
>> +++ b/mkfs/xfs_mkfs.c
>> @@ -454,12 +454,26 @@ static void get_topology(
>>  	struct fs_topology	*ft,
>>  	int			force_overwrite)
>>  {
>> -	if (!xi->disfile) {
>> -		const char *dfile = xi->volname ? xi->volname : xi->dname;
>> +	int is_a_file = 0;
>> +	struct stat statbuf;
>> +	char *dfile = xi->volname ? xi->volname : xi->dname;
>>  
>> +	if (!stat(dfile, &statbuf) && S_ISREG(statbuf.st_mode))
>> +		is_a_file = 1;
>> +
>> +	if (!xi->disfile && !is_a_file) {
> 
> Why do need both xi->disfile and a local flag/  Why do we do the
> that even if xi->disfile is set?

Good point that we don't need to do the stat if the old disfile flag
is already set.

But "disfile" implies a lot of other things, and comes from specifying
"-d file,..." on the cmdline.  If you point mkfs straight at a file,
disfile is NOT set, so I check it here explicitly.

The dichotomy between "mkfs.xfs -dfile,name=$FOO" and "mkfs.xfs $FOO"
is a weird one, and should probably just go away in the long run...

-Eric

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