[PATCH v3] xfs: probe data buffer from page cache for unwritten extents

[Jeff Liu]

On 07/17/2012 03:18 PM, Christoph Hellwig wrote:

> On Tue, Jul 03, 2012 at 03:15:56PM +0800, Jeff Liu wrote:
>> Hello,
>>
>> This is v3 of the patch.
>>
>> We can trigger BUG() in xfs_seek_data() if met two unwritten without data or hole extents at last version.
>> So making the extents map reading in loop could solve it.
>>
>> Sorry, Am not yet try the repeated holes scenario according to Dave's comments as lack of X64 test env, still
>> waiting for it ready.  But this patch is already too long delayed, I have worked it out one weeks ago.
>> So I'd like to post it because of it could handle repeated hole/unwritten extents well in a loop, and I also improved
>> xfstests:286 with those cases for the verification, will post it soon.
>>
>> v2->v3:
>> Tested by Mark, hit BUG() for continuous unwritten extents without data wrote.
>> * xfs_seek_data(), remove BUG() and having extents map search in loop.
> 
> The patch looks good.  But as question by Mark I wonder if it's a good
> idea to just improve xfs_seek_data, but not xfs_seek_hole.

I definitely would like to improve it.

Thanks,
-Jeff