Re: [PATCH] mkfs: default to CRC enabled filesystems

[Eric Sandeen <sandeen@sandeen.net>]

On 3/19/15 6:13 PM, Dave Chinner wrote:
> On Thu, Mar 19, 2015 at 09:55:25AM -0500, Eric Sandeen wrote:

...

>> Problem here is that if both are explicitly specified, one is ignored, rather
>> than letting the user know they've selected an invalid set of options:
> 
> Yup, I explicitly made that choice: turning off CRCs immediately
> turns off all functionality dependent on it. Especially as the
> number of errors being thrown by xfstests when run with
> MKFS_OPTIONS="-m crc=0".
> 
>> # mkfs/mkfs.xfs -dfile,name=fsfile,size=1g -m crc=0,finobt=1
>> meta-data=fsfile                 isize=256    agcount=4, agsize=65536 blks
>>          =                       sectsz=512   attr=2, projid32bit=1
>>          =                       crc=0        finobt=0
>> ...
> 
>> This might require a "finobtflag" to keep track of whether it's user-specified,
>> as we do with other options?
> 
> I *hate* the profusion of flags in mkfs just to detect this sort of
> thing. This is a clear case where "do what I mean" rather than "do
> what I say" is the prefered behaviour - the current code is a
> horrible mess because it tries handle every weird combination of "do
> what I say" with some error message.
> 
> I'll change it to add the stupid error message back in and go and
> write all the patches for xfstests not to fail because we changed
> mkfs defaults...

Oops, I accidentally missed reply-all last time.

I just think that silently changing an explicitly-specified option seems
like a bad idea.

Perhaps if defaults are specified before getopt, the getopt handlers can
flag the incorrect combination, and bail without the extra flag.

I don't see how this requires xfstests rework, though?

-Eric

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