zfs: default disable zfs_dmu_offset_next_sync to avoid data corruption
This helps mitigate a data corruption bug. This was previously defaulted
to zero prior to upstream commit
05b3eb6d232009db247882a39d518e7282630753, and it is already a tunable,
so doing this seems safe. Initially data corruption was thought to be
introduced with v2.2, but further upstream investigation currently
believes that changes in v2.2 only exacerbated the issue that already
existed.
A longer-term fix is likely to be
https://github.com/openzfs/zfs/pull/15571, though that is not yet
merged. The zfs_2_1 package has already backported that, so do not apply
the tunable default change there.
Positioning of `extraPatches` is to avoid merge conflicts with
https://github.com/NixOS/nixpkgs/pull/269097.
Patch is nearly identical to the [Gentoo][1] patch, but better patch
formatting.
See https://github.com/openzfs/zfs/issues/11900
See https://github.com/openzfs/zfs/issues/15526
[1]: https://gitweb.gentoo.org/repo/gentoo.git/tree/sys-fs/zfs-kmod/files/zfs-kmod-2.2.1-Disable-zfs_dmu_offset_next_sync-tunable-by-default.patch
9670ddc543