afs: Fix missing net error handling

kAFS can be given certain network errors (EADDRNOTAVAIL, EHOSTDOWN and
ERFKILL) that it doesn't handle in its server/address rotation algorithms.
They cause the probing and rotation to abort immediately rather than
rotating.

Fix this by:

 (1) Abstracting out the error prioritisation from the VL and FS rotation
     algorithms into a common function and expand usage into the server
     probing code.

     When multiple errors are available, this code selects the one we'd
     prefer to return.

 (2) Add handling for EADDRNOTAVAIL, EHOSTDOWN and ERFKILL.

Fixes: 0fafdc9f888b ("afs: Fix file locking")
Fixes: 0338747d8454 ("afs: Probe multiple fileservers simultaneously")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 13 insertions, 40 deletions

diff --git a/fs/afs/rotate.c b/fs/afs/rotate.c
index 00504254c1c2..c3ae324781f8 100644
--- a/fs/afs/rotate.c
+++ b/fs/afs/rotate.c
@@ -136,7 +136,8 @@ bool afs_select_fileserver(struct afs_fs_cursor *fc)
         struct afs_addr_list *alist;
         struct afs_server *server;
         struct afs_vnode *vnode = fc->vnode;
-        u32 rtt, abort_code;
+        struct afs_error e;
+        u32 rtt;
         int error = fc->ac.error, i;
 
         _enter("%lx[%d],%lx[%d],%d,%d",
@@ -306,8 +307,11 @@ bool afs_select_fileserver(struct afs_fs_cursor *fc)
                 if (fc->error != -EDESTADDRREQ)
                         goto iterate_address;
                 /* Fall through */
+        case -ERFKILL:
+        case -EADDRNOTAVAIL:
         case -ENETUNREACH:
         case -EHOSTUNREACH:
+        case -EHOSTDOWN:
         case -ECONNREFUSED:
                 _debug("no conn");
                 fc->error = error;
@@ -446,50 +450,15 @@ no_more_servers:
         if (fc->flags & AFS_FS_CURSOR_VBUSY)
                 goto restart_from_beginning;
 
-        abort_code = 0;
-        error = -EDESTADDRREQ;
+        e.error = -EDESTADDRREQ;
+        e.responded = false;
         for (i = 0; i < fc->server_list->nr_servers; i++) {
                 struct afs_server *s = fc->server_list->servers[i].server;
-                int probe_error = READ_ONCE(s->probe.error);
 
-                switch (probe_error) {
-                case 0:
-                        continue;
-                default:
-                        if (error == -ETIMEDOUT ||
-                            error == -ETIME)
-                                continue;
-                case -ETIMEDOUT:
-                case -ETIME:
-                        if (error == -ENOMEM ||
-                            error == -ENONET)
-                                continue;
-                case -ENOMEM:
-                case -ENONET:
-                        if (error == -ENETUNREACH)
-                                continue;
-                case -ENETUNREACH:
-                        if (error == -EHOSTUNREACH)
-                                continue;
-                case -EHOSTUNREACH:
-                        if (error == -ECONNREFUSED)
-                                continue;
-                case -ECONNREFUSED:
-                        if (error == -ECONNRESET)
-                                continue;
-                case -ECONNRESET: /* Responded, but call expired. */
-                        if (error == -ECONNABORTED)
-                                continue;
-                case -ECONNABORTED:
-                        abort_code = s->probe.abort_code;
-                        error = probe_error;
-                        continue;
-                }
+                afs_prioritise_error(&e, READ_ONCE(s->probe.error),
+                                     s->probe.abort_code);
         }
 
-        if (error == -ECONNABORTED)
-                error = afs_abort_to_error(abort_code);
-
 failed_set_error:
         fc->error = error;
 failed:
@@ -553,8 +522,11 @@ bool afs_select_current_fileserver(struct afs_fs_cursor *fc)
                 _leave(" = f [abort]");
                 return false;
 
+        case -ERFKILL:
+        case -EADDRNOTAVAIL:
         case -ENETUNREACH:
         case -EHOSTUNREACH:
+        case -EHOSTDOWN:
         case -ECONNREFUSED:
         case -ETIMEDOUT:
         case -ETIME:
@@ -633,6 +605,7 @@ int afs_end_vnode_operation(struct afs_fs_cursor *fc)
         struct afs_net *net = afs_v2net(fc->vnode);
 
         if (fc->error == -EDESTADDRREQ ||
+            fc->error == -EADDRNOTAVAIL ||
             fc->error == -ENETUNREACH ||
             fc->error == -EHOSTUNREACH)
                 afs_dump_edestaddrreq(fc);