Re: [PATCH 4/5] xfs: allow reusing busy extents where safe

Christoph Hellwig
2011-03-31T08:27:17Z

On Tue, Mar 29, 2011 at 02:04:28PM -0500, Alex Elder wrote:
> On Mon, 2011-03-28 at 17:06 -0400, Christoph Hellwig wrote:
> > Allow reusing any busy extent for metadata allocations, and reusing busy
> > userdata extents for userdata allocations. Most of the complexity is
> > propagating the userdata information from the XFS_BMAPI_METADATA flag
> > to xfs_bunmapi into the low-level extent freeing routines. After that
> > we can just track what type of busy extent we have and treat it accordingly.
> >
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
>
> The use of an enum value returned from
> xfs_alloc_busy_update_extent() is a good improvement.
>
> I'll issue the caveat here that I did not look through
> it this time as carefully as the first time. My main
> concern was about the validity of reusing busy user data
> extents for user data, and as before I'll say I accept
> that it's OK, but I haven't worked through in my own
> mind that it is indeed safe. If I find the time to do
> it I'll look this one over again to for reassurance...

This version doesn't actually allow userdata reallocations anymore,
I just forgot to update the patch description.