Hi Maximo We have moved to a GitLab MR based development workflow so please create an MR instead.
Instructions are at: https://gitlab.freedesktop.org/gnu-grub/grub/-/raw/master/CONTRIBUTING Leo On Fri, Jul 31, 2026 at 1:11 AM Maximo Guk via Grub-devel < [email protected]> wrote: > We don't need any actual adjustments as we don't use the affected > structures. > > Both features are read-incompatible - they are registered without > ZFEATURE_FLAG_READONLY_COMPAT and are therefore recorded in the pool's > features_for_read - so check_mos_features() refuses to mount any pool where > either is active. Neither affects a structure GRUB reads: > com.datto:bookmark_v2 only enlarges bookmark objects and > com.delphix:bookmark_written only adds bookmark accounting fields, while > GRUB > never enumerates bookmarks. Note that com.delphix:bookmarks itself is > READONLY_COMPAT and so never appears in features_for_read. > > This follows commit c464f1ec3 (fs/zfs/zfs: Mark vdev_zaps_v2 and > head_errlog > as supported), which added com.delphix:head_errlog - likewise recorded in > features_for_read and likewise unused by GRUB. > > Signed-off-by: Maximo Guk <[email protected]> > --- > Found this when a nightly ZFS send/recv backup created a bookmark on the > pool > holding /boot. The machine ran fine that day and simply failed to boot on > the > next restart, with nothing to indicate what had changed. > > Reproduced on Ubuntu 26.04 (GRUB 2.14, OpenZFS 2.4.1), single-pool ZFS > root: > creating a bookmark makes "grub-probe --target=fs /" fail (the same > check_mos_features() path used at boot), and destroying it restores both > the > feature state and booting. > > This is not specific to one backup tool - zrepl, sanoid/syncoid and > zfs-autobackup all create bookmarks to anchor incremental sends without > retaining snapshots. zrepl carries an open issue for the same interaction: > https://github.com/zrepl/zrepl/issues/501 > > Earlier discussion of GRUB's feature allowlist, including a proposal to > relax > check_mos_features() wholesale (this patch is the narrower alternative): > https://github.com/openzfs/zfs/discussions/15169 > > Happy to test any alternative approach. > > grub-core/fs/zfs/zfs.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/grub-core/fs/zfs/zfs.c b/grub-core/fs/zfs/zfs.c > index 83dfa6d52..5d0c50b69 100644 > --- a/grub-core/fs/zfs/zfs.c > +++ b/grub-core/fs/zfs/zfs.c > @@ -296,6 +296,8 @@ static const char *spa_feature_names[] = { > "com.klarasystems:vdev_zaps_v2", > "com.delphix:head_errlog", > "org.freebsd:zstd_compress", > + "com.datto:bookmark_v2", > + "com.delphix:bookmark_written", > NULL > }; > > -- > 2.53.0 > > _______________________________________________ > Grub-devel mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/grub-devel > >
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