NFS: Don't interrupt file writeout due to fatal errors

NFS: Don't interrupt file writeout due to fatal errors

BugLink: https://bugs.launchpad.net/bugs/1863019
[ Upstream commit 14bebe3c90b326d2a0df78aed5e9de090c71d878 ]

When flushing out dirty pages, the fact that we may hit fatal errors
is not a reason to stop writeback. Those errors are reported through
fsync(), not through the flush mechanism.

Fixes: a6598813a4c5b ("NFS: Don't write back further requests if there...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>