[PATCH v4 09/21] afs: check for duplicate servers in VL server list

[David Howells]

From: Yuto Ohnuki <ytohnuki at amazon.com>

The DNS response may contain the same server more than once. Check for
duplicates by name and port before inserting into the list to avoid
duplicate entries.

Addresses the TODO comment in afs_extract_vlserver_list().

Signed-off-by: Yuto Ohnuki <ytohnuki at amazon.com>
Signed-off-by: David Howells <dhowells at redhat.com>
cc: Marc Dionne <marc.dionne at auristor.com>
cc: linux-afs at lists.infradead.org
---
 fs/afs/vl_list.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/fs/afs/vl_list.c b/fs/afs/vl_list.c
index 003889cf0f18..8e1cf6cdcf71 100644
--- a/fs/afs/vl_list.c
+++ b/fs/afs/vl_list.c
@@ -289,8 +289,20 @@ struct afs_vlserver_list *afs_extract_vlserver_list(struct afs_cell *cell,
 			afs_put_addrlist(old, afs_alist_trace_put_vlserver_old);
 		}
 
+		/* Check for duplicates in the server list */
+		for (j = 0; j < vllist->nr_servers; j++) {
+			struct afs_vlserver *s = vllist->servers[j].server;
 
-		/* TODO: Might want to check for duplicates */
+			if (s->name_len == server->name_len &&
+			    s->port == server->port &&
+			    strncasecmp(s->name, server->name, server->name_len) == 0) {
+				afs_put_vlserver(cell->net, server);
+				server = NULL;
+				break;
+			}
+		}
+		if (!server)
+			continue;
 
 		/* Insertion-sort by priority and weight */
 		for (j = 0; j < vllist->nr_servers; j++) {