afs: Don't cache preferred address

In the AFS fileserver rotation algorithm, don't cache the preferred address
for the server as that will override the explicit preference if a
non-preferred address responds first.

Fixes: 495f2ae9e355 ("afs: Fix fileserver rotation")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20240313081505.3060173-2-dhowells@redhat.com
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/afs/rotate.c b/fs/afs/rotate.c
index 700a27bc8c257e920714359ceb168d7c6d7d6055..ed04bd1eeae89793219aacd1ada6efb61aa6ba03 100644 (file)
--- a/fs/afs/rotate.c
+++ b/fs/afs/rotate.c
@@ -602,6 +602,8 @@ iterate_address:
                goto wait_for_more_probe_results;
 
        alist = op->estate->addresses;
+       best_prio = -1;
+       addr_index = 0;
        for (i = 0; i < alist->nr_addrs; i++) {
                if (alist->addrs[i].prio > best_prio) {
                        addr_index = i;
@@ -609,9 +611,7 @@ iterate_address:
                }
        }
 
-       addr_index = READ_ONCE(alist->preferred);
-       if (!test_bit(addr_index, &set))
-               addr_index = __ffs(set);
+       alist->preferred = addr_index;
 
        op->addr_index = addr_index;
        set_bit(addr_index, &op->addr_tried);
@@ -656,12 +656,6 @@ wait_for_more_probe_results:
 next_server:
        trace_afs_rotate(op, afs_rotate_trace_next_server, 0);
        _debug("next");
-       ASSERT(op->estate);
-       alist = op->estate->addresses;
-       if (op->call_responded &&
-           op->addr_index != READ_ONCE(alist->preferred) &&
-           test_bit(alist->preferred, &op->addr_tried))
-               WRITE_ONCE(alist->preferred, op->addr_index);
        op->estate = NULL;
        goto pick_server;
 
@@ -690,14 +684,7 @@ no_more_servers:
 failed:
        trace_afs_rotate(op, afs_rotate_trace_failed, 0);
        op->flags |= AFS_OPERATION_STOP;
-       if (op->estate) {
-               alist = op->estate->addresses;
-               if (op->call_responded &&
-                   op->addr_index != READ_ONCE(alist->preferred) &&
-                   test_bit(alist->preferred, &op->addr_tried))
-                       WRITE_ONCE(alist->preferred, op->addr_index);
-               op->estate = NULL;
-       }
+       op->estate = NULL;
        _leave(" = f [failed %d]", afs_op_error(op));
        return false;
 }