[PATCH 1/2] afs: Fix ignored callbacks over ipv4

[David Howells]

From: Marc Dionne <marc.dionne@xxxxxxxxxxxx>

When searching for a matching peer, all addresses need to be searched,
not just the ipv6 ones in the fs_addresses6 list.

Given that the lists no longer contain addresses, there is little
reason to splitting things between separate lists, so unify them
into a single list.

When processing an incoming callback from an ipv4 address, this would
lead to a failure to set call->server, resulting in the callback being
ignored and the client seeing stale contents.

Fixes: 72904d7b9bfb ("rxrpc, afs: Allow afs to pin rxrpc_peer objects")
Reported-by: Markus Suvanto <markus.suvanto@xxxxxxxxx>
Link: https://lists.infradead.org/pipermail/linux-afs/2024-February/008035.html
Signed-off-by: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Link: https://lists.infradead.org/pipermail/linux-afs/2024-February/008037.html # v1
Link: https://lists.infradead.org/pipermail/linux-afs/2024-February/008066.html # v2
---
 fs/afs/internal.h |  6 ++----
 fs/afs/main.c     |  3 +--
 fs/afs/server.c   | 14 +++++---------
 3 files changed, 8 insertions(+), 15 deletions(-)

diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 9c03fcf7ffaa..6ce5a612937c 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -321,8 +321,7 @@ struct afs_net {
 	struct list_head	fs_probe_slow;	/* List of afs_server to probe at 5m intervals */
 	struct hlist_head	fs_proc;	/* procfs servers list */
 
-	struct hlist_head	fs_addresses4;	/* afs_server (by lowest IPv4 addr) */
-	struct hlist_head	fs_addresses6;	/* afs_server (by lowest IPv6 addr) */
+	struct hlist_head	fs_addresses;	/* afs_server (by lowest IPv6 addr) */
 	seqlock_t		fs_addr_lock;	/* For fs_addresses[46] */
 
 	struct work_struct	fs_manager;
@@ -561,8 +560,7 @@ struct afs_server {
 	struct afs_server __rcu	*uuid_next;	/* Next server with same UUID */
 	struct afs_server	*uuid_prev;	/* Previous server with same UUID */
 	struct list_head	probe_link;	/* Link in net->fs_probe_list */
-	struct hlist_node	addr4_link;	/* Link in net->fs_addresses4 */
-	struct hlist_node	addr6_link;	/* Link in net->fs_addresses6 */
+	struct hlist_node	addr_link;	/* Link in net->fs_addresses6 */
 	struct hlist_node	proc_link;	/* Link in net->fs_proc */
 	struct list_head	volumes;	/* RCU list of afs_server_entry objects */
 	struct afs_server	*gc_next;	/* Next server in manager's list */
diff --git a/fs/afs/main.c b/fs/afs/main.c
index 1b3bd21c168a..a14f6013e316 100644
--- a/fs/afs/main.c
+++ b/fs/afs/main.c
@@ -90,8 +90,7 @@ static int __net_init afs_net_init(struct net *net_ns)
 	INIT_LIST_HEAD(&net->fs_probe_slow);
 	INIT_HLIST_HEAD(&net->fs_proc);
 
-	INIT_HLIST_HEAD(&net->fs_addresses4);
-	INIT_HLIST_HEAD(&net->fs_addresses6);
+	INIT_HLIST_HEAD(&net->fs_addresses);
 	seqlock_init(&net->fs_addr_lock);
 
 	INIT_WORK(&net->fs_manager, afs_manage_servers);
diff --git a/fs/afs/server.c b/fs/afs/server.c
index e169121f603e..038f9d0ae3af 100644
--- a/fs/afs/server.c
+++ b/fs/afs/server.c
@@ -38,7 +38,7 @@ struct afs_server *afs_find_server(struct afs_net *net, const struct rxrpc_peer
 		seq++; /* 2 on the 1st/lockless path, otherwise odd */
 		read_seqbegin_or_lock(&net->fs_addr_lock, &seq);
 
-		hlist_for_each_entry_rcu(server, &net->fs_addresses6, addr6_link) {
+		hlist_for_each_entry_rcu(server, &net->fs_addresses, addr_link) {
 			estate = rcu_dereference(server->endpoint_state);
 			alist = estate->addresses;
 			for (i = 0; i < alist->nr_addrs; i++)
@@ -177,10 +177,8 @@ static struct afs_server *afs_install_server(struct afs_cell *cell,
 	 * bit, but anything we might want to do gets messy and memory
 	 * intensive.
 	 */
-	if (alist->nr_ipv4 > 0)
-		hlist_add_head_rcu(&server->addr4_link, &net->fs_addresses4);
-	if (alist->nr_addrs > alist->nr_ipv4)
-		hlist_add_head_rcu(&server->addr6_link, &net->fs_addresses6);
+	if (alist->nr_addrs > 0)
+		hlist_add_head_rcu(&server->addr_link, &net->fs_addresses);
 
 	write_sequnlock(&net->fs_addr_lock);
 
@@ -511,10 +509,8 @@ static void afs_gc_servers(struct afs_net *net, struct afs_server *gc_list)
 
 			list_del(&server->probe_link);
 			hlist_del_rcu(&server->proc_link);
-			if (!hlist_unhashed(&server->addr4_link))
-				hlist_del_rcu(&server->addr4_link);
-			if (!hlist_unhashed(&server->addr6_link))
-				hlist_del_rcu(&server->addr6_link);
+			if (!hlist_unhashed(&server->addr_link))
+				hlist_del_rcu(&server->addr_link);
 		}
 		write_sequnlock(&net->fs_lock);