Re: [RFC 0/5] Ext4: Add support for blocksize < pagesize for dioread_nolock

[Ritesh Harjani <riteshh@linux.ibm.com>]

On 11/4/19 3:46 PM, Matthew Bobrowski wrote:
> On Sun, Nov 03, 2019 at 02:16:06PM -0500, Theodore Y. Ts'o wrote:
>> On Tue, Oct 29, 2019 at 12:49:24PM +0530, Ritesh Harjani wrote:
>>>
>>> So it looks like these failed tests does not seem to be because of this
>>> patch series. But these are broken in general for at least 1K blocksize.
>>
>> Agreed, I failed to add them to the exclude list for diread_nolock_1k.
>> Thanks for pointing that out!
>>
>> After looking through these patches, it looks good.  So, I've landed
>> this series on the ext4 git tree.
>>
>> There are some potential conflicts with Matthew's DIO using imap patch
>> set.  I tried resolving them in the obvious way (see the tt/mb-dio
>> branch[1] on ext4.git), and unfortunately, there is a flaky test
>> failure with generic/270 --- 2 times out 30 runs of generic/270, the
>> file system is left inconsistent, with problems found in the block
>> allocation bitmap.
>>
>> [1] https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git/log/?h=tt/mb-dio
>>
>> I've verified that generic/270 isn't a problem on -rc3, and it's not a
>> problem with just your patch series.  So, it's almost certain it's
>> because I screwed up the merge.  I applied each of Matthew's patch one
>> at a time, and conflict was in changes in ext4_end_io_dio, which is
>> dropped in Matthew's patch.  It wasn't obvious though where the
>> dioread-nolock-1k change should be applied in Matthew's patch series.
>> Could you take a look?  Thanks!!
> 
> Hang on a second.
> 
> Are we not prematurely merging this series in with master? I thought
> that this is something that should've come after the iomap direct I/O
> port, no? The use of io_end's within the new direct I/O implementation
> are effectively redundant...

It sure may be giving a merge conflict (due to io_end structure).
But this dioread_nolock series was not dependent over iomap series.

-ritesh