On Thu, Mar 31, 2005 at 07:31:01PM +0100, James Chapman wrote:
> Nathan Scott wrote:
> > On Wed, Mar 30, 2005 at 07:43:48PM +0100, James Chapman wrote:
> >>Do you know of any differences with which ext2/ext3 and xfs use the VFS
> >>interfaces? I've been using a h/w debugger all day on this and I see
> > Yes, the main one is XFS's use of delayed allocation (i.e. a buffer_head
> > with the BH_delay flag set on it -- ext2/3 don't use that, XFS does).
> Thanks for the info.
> >>writepage() write data as expected, but readpage() _never_ reads the
> >>disk for file data. block_read_full_page() never gets a mapped buffer
> > If its cached (BH_uptodate) it doesn't need to be read from disk,
> > thats probably the behaviour your seeing.
> But I umount the disk, remount and then do the read in this test.
Try using xfs_db to look at the inode after unmounting, perhaps
the inode extent map wasn't flushed or something like that? In
that case, there'd be no read from disk too.
> btw, I finally got hold of an old x86 box today. I installed RH9 and
> rebuilt the exact vendor 2.4.25 kernel (with config changes needed for
> x86). I also installed the latest xfsprogs. Sure enough, XFS just works
> so we now know the problem is platform specific.
> I'm getting the platform vendor involved now. If I find that any xfs
> changes are needed to support my arch (unlikely) then I'll let you know.
Ah, OK. CC'ing linux-xfs, for the person who sent me private mail
saying he was worried about this. (you know who you are :)
> One more question. Is there an open source disk stress test that you
> know of? I have LTP but it is too bloated to run on an embedded system.
You can use the tools from xfs-cmds/xfstests -- some of those are in
LTP too, some aren't.