Re: [PATCH 06/27] xfs: split xfs_setattr

Alex Elder
2011-06-30T12:28:27Z

On Thu, 2011-06-30 at 03:03 -0400, Christoph Hellwig wrote:
> On Wed, Jun 29, 2011 at 05:13:16PM -0500, Alex Elder wrote:
> > Looks good but I think that you need to mask off the
> > ia_valid bits in the calls now made in xfs_vn_setattr().
>
> Why? We call xfs_setattr_size if ATTR_SIZE is set. The ATTR_SIZE
> may also have a few other attributes we can handle, and assert on
> those that it can't just to make sure. Similarly xfs_setattr_nonsize
> can handle everything but ATTR_SIZE, and again we have an assert to
> protect against breeding incorrect XFS-internal callers.

OK. I didn't go that far back, or at least didn't check all
the notify_change() calls. I now have, and although I'm not
100% sure on encryptfs and nfsd setattr it looks like you're
right. That basically explains all of my comments--the VFS
prevents those conditions from occurring, and therefore an
assertion to communicate and enforce that is proper.

Reviewed-by: Alex Elder <aelder@sgi.com>

> > Also, I think you may still need to check the file type
> > for the size-setting function. Details below.
>
> The VFS only ever does an ATTR_SIZE setattr on regular files. We have
> an assert to ensure that for debug builds, which is a lot more than
> most other filesystems do.
>
> > > + ASSERT((mask & (ATTR_MODE|ATTR_UID|ATTR_GID|ATTR_ATIME|ATTR_ATIME_SET|
> > > + ATTR_MTIME_SET|ATTR_KILL_SUID|ATTR_KILL_SGID|
> > > + ATTR_KILL_PRIV|ATTR_TIMES_SET)) == 0);
> >
> > You'll have to mask these off in xfs_vn_setattr() if you're
> > going to make this assertion.
>
> No, this is the (implicit) calling convention by the VFS.
>
> > > - if (S_ISDIR(ip->i_d.di_mode)) {
> > > - code = XFS_ERROR(EISDIR);
> > > - goto error_return;
> > > - } else if (!S_ISREG(ip->i_d.di_mode)) {
> > > - code = XFS_ERROR(EINVAL);
> > > - goto error_return;
> > > - }
> >
> > This is the file type checking code I referred to above.
>
> It simply was a leftover from IRIX that we can't hit on Linux.