Re: [GRUB PATCH] xfs: accept filesystem with sparse inodes

[Daniel Kiper]

On Tue, May 15, 2018 at 02:55:55PM -0500, Eric Sandeen wrote:
> The sparse inode metadata format became a mkfs.xfs default in
> xfsprogs-4.16.0, and such filesystems are now rejected by grub as
> containing an incompatible feature.
>
> In essence, this feature allows xfs to allocate inodes into fragmented
> freespace.  (Without this feature, if xfs could not allocate contiguous
> space for 64 new inodes, inode creation would fail.)
>
> In practice, the disk format change is restricted to the inode btree,
> which as far as I can tell is not used by grub.  If all you're doing
> today is parsing a directory, reading an inode number, and converting
> that inode number to a disk location, then ignoring this feature
> should be fine, so I've added it to XFS_SB_FEAT_INCOMPAT_SUPPORTED
>
> I did some brief testing of this patch by hacking up the regression
> tests to completely fragment freespace on the test xfs filesystem, and
> then write a large-ish number of inodes to consume any existing
> contiguous 64-inode chunk.  This way any files the grub tests add and
> traverse would be in such a fragmented inode allocation.  Tests passed,
> but I'm not sure how to cleanly integrate that into the test harness.
>
> Signed-off-by: Eric Sandeen <address@hidden>

Eric, thank you for posting the patch. LGTM.

Chris, may I ask you to test it and add your "Tested-by:" if it works?

Daniel