This patch addresses running `zpool scrub <pool>` with ZFS 2.4 userspace
while the loaded kernel module is still 2.3, failing with:
```
cannot scrub <pool>: the loaded zfs module does not support an option
for this operation. A reboot may be required to enable this option.
```
Checking for the source of the message via `strace` showed the scrub
ioctl failing and setting errno to ZFS_ERR_IOC_ARG_UNAVAIL[0]. With
that and the comments in `module/zfs/zfs_ioctl.c`[1] commit: 894edd084
seemed like a likely cause for the backward incompatibility.
The corresponding kernelspace code in `module/zfs/zfs_ioctl.c` defaults
to a setting of 0 if either parameter is not set, so not providing the
nvpairs in case both are 0 should not make a semantic difference.
Tested by:
* loading zfs.ko in version 2.3.6
* running `zpool scrub testpool` with zpool from master (error occurs)
* running `zpool scrub testpool` with this patch applied (scrub is
started)
This should help users who are still stuck on an older kernel module,
while their distribution ships newer ZFS userspace.
This was observed in the Proxmox community forum:
https://forum.proxmox.com/threads/.180467/
[0] d35951b18d/include/sys/fs/zfs.h (L1762)
[1] d35951b18d/module/zfs/zfs_ioctl.c (L7799)
Fixes: 894edd084 ("Add TXG timestamp database")
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>
Co-authored-by: Stoiko Ivanov <s.ivanov@proxmox.com>
Closes#18314
7f65e04abd