[PATCH 3/8] mountd: remove 'dev_missing' checks

[NeilBrown <neilb@suse.com>]

I now think this was a mistaken idea.

If a filesystem is exported with the "mountpoint" or "mp" option, it
should only be exported if the directory is a mount point.  The
intention is that if there is a problem with one filesystem on a
server, the others can still be exported, but clients won't
incorrectly see the empty directory on the parent when accessing the
missing filesystem, they will see clearly that the filesystem is
missing.

It is easy to handle this correctly for NFSv3 MOUNT requests, but what
is the correct behavior if a client already has the filesystem mounted
and so has a filehandle?  Maybe the server rebooted and came back with
one device missing.  What should the client see?

The "dev_missing" code tries to detect this case and causes the server
to respond with silence rather than ESTALE.  The idea was that the
client would retry and when (or if) the filesystem came back, service
would be transparently restored.

The problem with this is that arbitrarily long delays are not what
people would expect, and can be quite annoying.  ESTALE, while
unpleasant, it at least easily understood.  A device disappearing is a
fairly significant event and hiding it doesn't really serve anyone.

So: remove the code and allow ESTALE.

Signed-off-by: NeilBrown <neilb@suse.com>
---
 utils/mountd/cache.c |   12 ------------
 1 file changed, 12 deletions(-)

diff --git a/utils/mountd/cache.c b/utils/mountd/cache.c
index ec86a22613cf..346a8b3af8b5 100644
--- a/utils/mountd/cache.c
+++ b/utils/mountd/cache.c
@@ -687,7 +687,6 @@ static void nfsd_fh(int f)
 	char *found_path = NULL;
 	nfs_export *exp;
 	int i;
-	int dev_missing = 0;
 	char buf[RPC_CHAN_BUF_SIZE], *bp;
 	int blen;
 
@@ -754,11 +753,6 @@ static void nfsd_fh(int f)
 			if (!is_ipaddr_client(dom)
 					&& !namelist_client_matches(exp, dom))
 				continue;
-			if (exp->m_export.e_mountpoint &&
-			    !is_mountpoint(exp->m_export.e_mountpoint[0]?
-					   exp->m_export.e_mountpoint:
-					   exp->m_export.e_path))
-				dev_missing ++;
 
 			if (!match_fsid(&parsed, exp, path))
 				continue;
@@ -801,12 +795,6 @@ static void nfsd_fh(int f)
 		/* FIXME we need to make sure we re-visit this later */
 		goto out;
 	}
-	if (!found && dev_missing) {
-		/* The missing dev could be what we want, so just be
-		 * quite rather than returning stale yet
-		 */
-		goto out;
-	}
 
 	if (found)
 		if (cache_export_ent(buf, sizeof(buf), dom, found, found_path) < 0)