posix_fallocate on ZFS

[Alan Somers]

On Sat, Feb 10, 2018 at 10:28 AM, Willem Jan Withagen <wjw at digiware.nl>
wrote:

> Hi,
>
> This has been disabled on ZFS since last November.
> And I do understand the rationale on this.
>
> BUT
>
> I've now upgraded some of my HEAD Ceph test systems and they now fail,
> since Ceph uses posix_fallocate() to allocate space for the
> FileStore-journal.
>
> Is there any expectation that this is going to fixed in any near future?
>
> --WjW
>

No.  It's fundamentally impossible to support posix_fallocate on a COW
filesystem like ZFS.  Ceph should be taught to ignore an EINVAL result,
since the system call is merely advisory.

-Alan