Re: [PATCH 06/13] xfs: xfs_sync_data is redundant.

Brian Foster
2012-10-02T21:13:42Z

On 10/02/2012 04:51 PM, Dave Chinner wrote:
> On Tue, Oct 02, 2012 at 09:01:33AM -0400, Brian Foster wrote:
>> On 10/01/2012 08:44 PM, Brian Foster wrote:
>>> On 10/01/2012 08:10 PM, Dave Chinner wrote:
>> ...
>>>
...
>
> I don't think we can do an unconditional down_read() there, as the
> caller from xfs_create() already holds an i_mutex (the VFS holds the
> directory inode lock) and I'm pretty sure that s_umount is supposed
> to be outside per-inode locks.
>
> Given that where we are called we are inside a transaction for the
> create case, and inside mnt_want_write() protection for the buffered
> write case, the likelyhood of s_umount being held for write at
> ENOSPC is going to be non-existent at these call sites. Hence a
> down_read_trylock() will avoid lock ordering issues, but will almost
> always succeed and so be equivalent to down_read()....
>

Ok...

> /me modifies and runs 273 and the enospc xfstests group...
>
> Seems to work just fine, and no warnings. Patch below.
>

This passes 273 clean (save the xlog_verify_grant_tail message) for me
as well. Thanks.

Brian

> Cheers,
>
> Dave.