Re: [WTF] ... is going on with current->fs->{root,mnt} accesses inpohmelfs

From: Al Viro
Date: Wed Feb 10 2010 - 16:02:54 EST


On Wed, Feb 10, 2010 at 04:30:07PM +0300, Evgeniy Polyakov wrote:
> > > > Why not use the dentries you've been given by VFS?
> > >
> > > At writeback we do not have parents, so must find a path somehow.
> >
> > Most of the places do have those just fine and unlike the writeback,
> > rename et.al. really care which pathname is being dealt with...
>
> POHMELFS uses writeback cache also for metadata, so effectively most of
> such operations are also postponed. Later I turned that off though.
>
> > BTW, what prevents writeback vs. rename races?
>
> There are proper locks for such operations.

Which would be... ? E.g. between writepages() and rename(). What serializes
your write_inode_create() wrt renames? IOW, how can the server decide that
data from writepages() should go to the same object regardless of the
rename?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/