10.1 mmap on zfs not updating mtime

[Andriy Gapon]

On 02/12/2014 03:27, Paul Koch wrote:
> On Mon, 01 Dec 2014 10:10:11 +0200
> Andriy Gapon <avg at FreeBSD.org> wrote:
> 
>> On 25/11/2014 06:23, Paul Koch wrote:
>>>
>>> Hi,
>>>
>>> we have observed some odd behaviour with the mtime of a mmap'ed file
>>> when it has been updated on a zfs pool.  The mtime does not appear to
>>> be updated.  Seems to work ok on UFS.
>>
>> Could you please test the following simple patch?
>> Index: sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
>> ===================================================================
>> --- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c	(revision 275036)
>> +++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c	(working copy)
>> @@ -5969,6 +5969,7 @@ top:
>>  		    &zp->z_pflags, 8);
>>  		zfs_tstamp_update_setup(zp, CONTENT_MODIFIED, mtime, ctime,
>>  		    B_TRUE);
>> +		(void)sa_bulk_update(zp->z_sa_hdl, bulk, count, tx);
>>  		zfs_log_write(zfsvfs->z_log, tx, TX_WRITE, zp, off, len, 0);
>>
>>  		zfs_vmobject_wlock(object);
>>
>>> Test program below...
>>>
>>> On 10.0, the following works ok:
>>>
>>>  dd bs=1k if=/dev/zero of=mdata count=1
>>>  ls -lT mdata; /tmp/mmap-mtime mdata; ls -lT mdata
>>>
>>> but on 10.1 the mtime stays at its creation time.
>> [snip]
>>
> 
> Applied the same change to 10.1-RELEASE and it fixed the problem.

Thank you for reporting the problem and testing the patch!

> Don't know how this affects other applications running on 10.1, but we've
> applied a workaround for ours by calling futimes() after we do a fsync()
> or between munmap()/close() on a mmap'ed file.

-- 
Andriy Gapon