[dm-devel] 2.6.3-udm5

[Kevin Corry]

On Monday 01 March 2004 8:36 am, Christophe Saout wrote:
> Hi,
>
> > Revision 19:
> >   dm_suspend(): Don't unlock the fs if a race with another suspend is
> >   detected.
>
> I've got a question: Is it stupid to move the __unlock_fs from dm_resume
> to the end of dm_suspend? My webserver loves to deadlock when trying to
> snapshot the root volume without it... unfortunately I don't have direct
> access to the machine so I can't find out what exactly happens (it
> happened twice and I'm not to excited trying it too often because the
> watchdog reboots the machine hard after some minutes).
>
> Trying to avoid having a filesystem locked between two syscalls is
> probably not a too bad idea. If the filesystem is unlocked after
> BLOCK_IO is set the filesystem will be in a clean state and new requests
> will be deferred and submitted to the new table after resume anyway.
> This doesn't make a difference with the suspend syscall but seems to do
> with.

I'd say it really depends on if the filesystems' unlockfs calls can block 
waiting for I/O to complete. If they can, I'd think it would be invalid to 
call unlockfs while the device is suspended. If we can ensure that the 
filesystem will *never* block during that call, your suggestion might work. 
Of course, I don't know enough about the various filesystems to answer that 
question.

-- 
Kevin Corry
kevcorry at us.ibm.com
http://evms.sourceforge.net/