[Linux-cachefs] Problems testing Lustre filesystem with fscache / cachefiles

[David Howells]

John Groves <grovesaustin at gmail.com> wrote:

> Dec 17 12:50:14 violin cachefilesd[5323]: readdir returned unknown type:
> errno 4 (Interrupted system call)

That would be:

	if (dirent.d_type == DT_UNKNOWN)
		oserror("readdir returned unknown type");

Which suggests the backing filesystem didn't indicate file type of a dir entry
through readdir().  Is this from Ext3, or is it from XFS?

> I might consider trying the back port... Do you have a recommendation as to
> what patch to start with?

Start with the latest patches.  Trim away anything that requires weird
security stuff.

> Also, might it be easier just to back port cachefiles?  I suppose that will
> be sensitive to the readv/aio_read change, etc.  If I could back port a
> patch that was better, but not complete modern, it might be easier...or does
> that sound like a mess to you?

You can't just backport cachefiles, unfortunately.  The newer FS-Cache stuff
has a load of asynchronicity stuff in there that affects cachefiles too.

One problem you've got with RHEL-5 is that you need to add an extra address
operation, but that would violate the kABI:-/

David