[Bug 2077487] Re: Broken atime in 2.2.2-0ubuntu9 (noble's version)

(https://git.launchpad.net/ubuntu/+source/linux-
hwe-6.8/tree/debian.hwe-6.8/dkms-versions?h=applied/ubuntu/jammy-devel
still references 2.2.2-0ubuntu9, for example)

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https://bugs.launchpad.net/bugs/2077487

Title:
Broken atime in 2.2.2-0ubuntu9 (noble's version)

Status in linux package in Ubuntu:
Invalid
Status in linux-hwe-6.8 package in Ubuntu:
Invalid
Status in zfs-linux package in Ubuntu:
Fix Released
Status in linux source package in Noble:
Confirmed
Status in linux-hwe-6.8 source package in Noble:
Invalid
Status in zfs-linux source package in Noble:
Fix Released

Bug description:
SRU Justification

[Impact]

* 2.2.2-0ubuntu9 has the 6.7 compat series, including https://github.com/openzfs/zfs/commit/db4fc559cc1931b9219e62aa505cd5c51a17b232, but does not include the fix for that commit (affects both pre-6.7 and post-6.7),
https://github.com/openzfs/zfs/commit/f0bf7a247dbb030d68c7fd2b5526dd111cc775d0. This manifests for me on the current (6.8.0-40.40~22.04.3) 22.04 HWE kernel as writes to a file resetting atime back to 0 (reads still seem to work as expected though given that state), which of course breaks real-world things (in my case, I can no longer successfully run LLVM's test suite).

Thanks to CONFIG_INIT_STACK_ALL_ZERO=y being the default it seems like
this isn't a kernel memory disclosure and is instead a deterministic
use of 0, so I don't believe this to be a blatant security
vulnerability. This also explains the behaviour observed above.

This needs fixing in noble, and then propagating back through whatever
kernels are pulling in this version, since linux-modules vendors
copies of the pre-built DKMS modules, with the current 6.8 HWE kernel
using 2.2.2-0ubuntu9 explicitly.

[Fix]

* Include f0bf7a247dbb: "[PATCH] Linux 6.7 compat: zfs_setattr fix
atime update" from upstream ZFS as quilt patch.

[Test Case]

* Build tested against Noble generic
* Ran autopkgktests for regressions, none encountered
* Ran the following test case:

Using zfs-linux 2.2.2-0ubuntu9
$ cd /path/to/zfs
$ rm -f foo
$ touch foo
$ stat foo
$ # observe initial access time of 0 since epoch (1970-01-01)

Using zfs-linux 2.2.2-0ubuntu9.1
$ cd /path/to/zfs
$ rm -f foo
$ touch foo
$ stat foo
$ # observe initial access time same as modify/change/birth

Also see results attached as "zfs-bad" and "zfs-good", respectively

[Where things could go wrong]

* Low chance of regression, isolated instantiation and logic fix.
* Addition of time delta check could cause issues during unexpected delay > 2 seconds.

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