[PATCH 3/6] nfsd_fh: if two exports are possible, choose the one without V4ROOT

[Neil Brown <neilb@suse.de>]

When nfsd_fh it looking for an export for a particular
client and file-handle, it might find two exports for the same path:
one with NFSEXP_V4ROOT, one with out.

As nfsd_fh calls cache_export_ent to give the export information to
the kernel it much choose the same export that auth_authenticate
chooses for get_rootfh which it also passes cache_export_ent (via
cache_export).
i.e. it must choose the non-V4ROOT on where possible.

Also change
   strcmp(foo, bar)
to
   strcmp(foo, bar) == 0
because I have a pathological fear of the former.

Signed-off-by: NeilBrown <neilb@suse.de>
---

 utils/mountd/cache.c |   11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/utils/mountd/cache.c b/utils/mountd/cache.c
index b01c0bd..0af6404 100644
--- a/utils/mountd/cache.c
+++ b/utils/mountd/cache.c
@@ -596,11 +596,20 @@ static void nfsd_fh(FILE *f)
 				found_path = strdup(path);
 				if (found_path == NULL)
 					goto out;
-			} else if (strcmp(found->e_path, exp->m_export.e_path)
+			} else if (strcmp(found->e_path, exp->m_export.e_path) != 0
 				   && !subexport(found, &exp->m_export))
 			{
 				xlog(L_WARNING, "%s and %s have same filehandle for %s, using first",
 				     found_path, path, dom);
+			} else {
+				/* same path, if one is V4ROOT, choose the other */
+				if (found->e_flags & NFSEXP_V4ROOT) {
+					found = &exp->m_export;
+					free(found_path);
+					found_path = strdup(path);
+					if (found_path == NULL)
+						goto out;
+				}
 			}
 		}
 	}