[PATCH, RFC] xfs: batched discard support

[Mark Lord]

Christoph Hellwig wrote:
> On Sun, Aug 16, 2009 at 09:59:32AM -0400, Mark Lord wrote:
>> Okay, I got Matthews patches updated onto 2.6.31, and fixed the incompatibilities
>> between those and the XFS TRIM patch (from Christoph), plus a sector_t printk issue.
>>
>> My apologies for attachments, but I am attaching the updated Christoph patch,
>> as well as my hacked-up forward-port of Matthew's patches.
>>
>> Not pretty, but they work.  :)
>>
>> Now.. running Christoph's "xfs trim" on a 4.6GB mostly already-trimmed
>> XFS partition gave this for the first time around:
> 
>> The problem is, it still issues TRIMs to the LLD one extent at a time.
>> Compare this with doing it all in a single TRIM command
>> with the wiper.sh script (filesystem unmounted):
> 
> I could do a variant which issues a single TRIM, but that would require
> us to lock out all other allocations for the time the trim takes.  I'll
> hack that up once I get some time.
..

Matthew's stuff will have to change to support that, too.