Hi Olga,
On 23/02/2022 18:56, Olga Kornievskaia wrote:
On Wed, Feb 23, 2022 at 8:20 AM Kurt Garloff <kurt@xxxxxxxxxx> wrote:
Hi Olga,
any updates? Were you able to investigate the traces?
Breaking NFS mounts from Qnap (knfsd with 3.4.6 kernel here,
though Qnap might have patched it),is not something that
should happen with a -stable kernel update, even if the problem
would be on the Qnap side, which would not be completely
surprising.
So I think we should revert this patch at least for -stable,
unless we understand what's going on and have a better fix
than a plain revert.
I haven't commented on your ask of requesting a revert in the stable
version. I'm not sure what the philosophy there. I don't see why we
can't ask for this feature to only be available from the kernel
version it has been accepted into and not before. If you think the
kernel version that you want to use will always be before this feature
was accepted, then asking folks responsible for "stable" kernels seems
like a good idea. At the time of inclusion to stable, I wasn't aware
of the broken legacy server implementations out there.
I guess Greg would need to comment on the detailed policies
for stable kernels.
One of the goals for sure is to avoid regressions. If that causes
bugs not to be fixable or features not to be available, than that's
a price that might need to be accepted. A regression is just many many
times worse than an unfixed issue, twice so for something that claims
to be stable.
So, if we are relatively sure that no NFSv4.2 server has the
kernel-3.4.6-knfsd Qnap (NFSv4.1) misbehavior, my change that masks the
new features for NFS<v4.2 might be what makes this patch acceptable
for stable. Otherwise, we should either revert it or make it
opt-in. The latter is not really a good idea if we then differ
from the main branch where we might go for an opt-out solution.
So maybe it's opt-out for main branch and for stable with an
additional guard against NFS<v4.2 at least for -stable.
Just my 0.02€.
--
Kurt Garloff <kurt@xxxxxxxxxx>
Cologne, Germany
