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Backport overlayfs features for composefs

Alexander Larsson requested to merge alexlarsson/cs-9-kernel:ovl-verity-backport into main

The automotive project plan on using composefs, and it needs some overlayfs backports from mainline kernel.

The minimal set of required features are:

  • Support for data-only lower layers (landed in 6.5)
  • Support for fs-verity validated metacopy (landed in 6.6rc1)

However, to make the backport work it also contains a select set of preparatory backports. These are mainly internal only changes, rather than features.

The amount of conflicts are low, and the ones that are there is mainly due to the idmap support not being backported, and the params.c rework in master. There is one patch marked RHEL-only ("ovl: Fix ovl_xattr_set use ovl_dentry_lower()"), but this really is a partial backport of an existing commit.

Content of patchset:

  • 1-4 - Preparatory overlayfs backports (1 is partial)
  • 5-16 - Overlayfs support for data-only layers
  • 17-19 - Adds fsverity_get_digest()
  • 20-23 - Overlayfs suport for fs-verity validation

I tested this with the v2023.09.03 version of xfstest, using the overlayfs test on top of ext4. With fs-verity enabled this passes the same tests as before, plus the new tests overlay/079 and overlay/080 that tests these new features.

JIRA: https://issues.redhat.com/browse/RHEL-2146

Signed-off-by: Alexander Larsson alexl@redhat.com

Edited by Alexander Larsson

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