NFS: fsync() should report filesystem errors over EINTR/ERESTARTSYS

NFS: fsync() should report filesystem errors over EINTR/ERESTARTSYS

[ Upstream commit 9641d9bc9b75f11f70646f5c6ee9f5f519a1012e ]

If the commit to disk is interrupted, we should still first check for
filesystem errors so that we can report them in preference to the error
due to the signal.

Fixes: 2197e9b06c22 ("NFS: Fix up fsync() when the server rebooted")
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>