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>

6 files changed, 135 insertions, 113 deletions

diff --git a/fs/afs/fs_probe.c b/fs/afs/fs_probe.c
index d049cb459742..fde6b4d4121e 100644
--- a/fs/afs/fs_probe.c
+++ b/fs/afs/fs_probe.c
@@ -61,8 +61,11 @@ void afs_fileserver_probe_result(struct afs_call *call)
                 afs_io_error(call, afs_io_error_fs_probe_fail);
                 goto out;
         case -ECONNRESET: /* Responded, but call expired. */
+        case -ERFKILL:
+        case -EADDRNOTAVAIL:
         case -ENETUNREACH:
         case -EHOSTUNREACH:
+        case -EHOSTDOWN:
         case -ECONNREFUSED:
         case -ETIMEDOUT:
         case -ETIME:
@@ -132,12 +135,14 @@ out:
 static int afs_do_probe_fileserver(struct afs_net *net,
                                    struct afs_server *server,
                                    struct key *key,
-                                   unsigned int server_index)
+                                   unsigned int server_index,
+                                   struct afs_error *_e)
 {
         struct afs_addr_cursor ac = {
                 .index = 0,
         };
-        int ret;
+        bool in_progress = false;
+        int err;
 
         _enter("%pU", &server->uuid);
 
@@ -151,15 +156,17 @@ static int afs_do_probe_fileserver(struct afs_net *net,
         server->probe.rtt = UINT_MAX;
 
         for (ac.index = 0; ac.index < ac.alist->nr_addrs; ac.index++) {
-                ret = afs_fs_get_capabilities(net, server, &ac, key, server_index,
+                err = afs_fs_get_capabilities(net, server, &ac, key, server_index,
                                               true);
-                if (ret != -EINPROGRESS) {
-                        afs_fs_probe_done(server);
-                        return ret;
-                }
+                if (err == -EINPROGRESS)
+                        in_progress = true;
+                else
+                        afs_prioritise_error(_e, err, ac.abort_code);
         }
 
-        return 0;
+        if (!in_progress)
+                afs_fs_probe_done(server);
+        return in_progress;
 }
 
 /*
@@ -169,21 +176,23 @@ int afs_probe_fileservers(struct afs_net *net, struct key *key,
                           struct afs_server_list *list)
 {
         struct afs_server *server;
-        int i, ret;
+        struct afs_error e;
+        bool in_progress = false;
+        int i;
 
+        e.error = 0;
+        e.responded = false;
         for (i = 0; i < list->nr_servers; i++) {
                 server = list->servers[i].server;
                 if (test_bit(AFS_SERVER_FL_PROBED, &server->flags))
                         continue;
 
-                if (!test_and_set_bit_lock(AFS_SERVER_FL_PROBING, &server->flags)) {
-                        ret = afs_do_probe_fileserver(net, server, key, i);
-                        if (ret)
-                                return ret;
-                }
+                if (!test_and_set_bit_lock(AFS_SERVER_FL_PROBING, &server->flags) &&
+                    afs_do_probe_fileserver(net, server, key, i, &e))
+                        in_progress = true;
         }
 
-        return 0;
+        return in_progress ? 0 : e.error;
 }
 
 /*
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 5da3b09b7518..8871b9e8645f 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -696,6 +696,14 @@ struct afs_interface {
 };
 
 /*
+ * Error prioritisation and accumulation.
+ */
+struct afs_error {
+        short   error;                  /* Accumulated error */
+        bool    responded;              /* T if server responded */
+};
+
+/*
  * Cursor for iterating over a server's address list.
  */
 struct afs_addr_cursor {
@@ -1015,6 +1023,7 @@ static inline void __afs_stat(atomic_t *s)
  * misc.c
  */
 extern int afs_abort_to_error(u32);
+extern void afs_prioritise_error(struct afs_error *, int, u32);
 
 /*
  * mntpt.c
diff --git a/fs/afs/misc.c b/fs/afs/misc.c
index 700a5fa7f4ec..bbb1fd51b019 100644
--- a/fs/afs/misc.c
+++ b/fs/afs/misc.c
@@ -118,3 +118,55 @@ int afs_abort_to_error(u32 abort_code)
         default:                return -EREMOTEIO;
         }
 }
+
+/*
+ * Select the error to report from a set of errors.
+ */
+void afs_prioritise_error(struct afs_error *e, int error, u32 abort_code)
+{
+        switch (error) {
+        case 0:
+                return;
+        default:
+                if (e->error == -ETIMEDOUT ||
+                    e->error == -ETIME)
+                        return;
+        case -ETIMEDOUT:
+        case -ETIME:
+                if (e->error == -ENOMEM ||
+                    e->error == -ENONET)
+                        return;
+        case -ENOMEM:
+        case -ENONET:
+                if (e->error == -ERFKILL)
+                        return;
+        case -ERFKILL:
+                if (e->error == -EADDRNOTAVAIL)
+                        return;
+        case -EADDRNOTAVAIL:
+                if (e->error == -ENETUNREACH)
+                        return;
+        case -ENETUNREACH:
+                if (e->error == -EHOSTUNREACH)
+                        return;
+        case -EHOSTUNREACH:
+                if (e->error == -EHOSTDOWN)
+                        return;
+        case -EHOSTDOWN:
+                if (e->error == -ECONNREFUSED)
+                        return;
+        case -ECONNREFUSED:
+                if (e->error == -ECONNRESET)
+                        return;
+        case -ECONNRESET: /* Responded, but call expired. */
+                if (e->responded)
+                        return;
+                e->error = error;
+                return;
+
+        case -ECONNABORTED:
+                e->responded = true;
+                e->error = afs_abort_to_error(abort_code);
+                return;
+        }
+}
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);
diff --git a/fs/afs/vl_probe.c b/fs/afs/vl_probe.c
index c0f616bd70cb..f0b032976487 100644
--- a/fs/afs/vl_probe.c
+++ b/fs/afs/vl_probe.c
@@ -61,8 +61,11 @@ void afs_vlserver_probe_result(struct afs_call *call)
                 afs_io_error(call, afs_io_error_vl_probe_fail);
                 goto out;
         case -ECONNRESET: /* Responded, but call expired. */
+        case -ERFKILL:
+        case -EADDRNOTAVAIL:
         case -ENETUNREACH:
         case -EHOSTUNREACH:
+        case -EHOSTDOWN:
         case -ECONNREFUSED:
         case -ETIMEDOUT:
         case -ETIME:
@@ -129,15 +132,17 @@ out:
  * Probe all of a vlserver's addresses to find out the best route and to
  * query its capabilities.
  */
-static int afs_do_probe_vlserver(struct afs_net *net,
-                                 struct afs_vlserver *server,
-                                 struct key *key,
-                                 unsigned int server_index)
+static bool afs_do_probe_vlserver(struct afs_net *net,
+                                  struct afs_vlserver *server,
+                                  struct key *key,
+                                  unsigned int server_index,
+                                  struct afs_error *_e)
 {
         struct afs_addr_cursor ac = {
                 .index = 0,
         };
-        int ret;
+        bool in_progress = false;
+        int err;
 
         _enter("%s", server->name);
 
@@ -151,15 +156,17 @@ static int afs_do_probe_vlserver(struct afs_net *net,
         server->probe.rtt = UINT_MAX;
 
         for (ac.index = 0; ac.index < ac.alist->nr_addrs; ac.index++) {
-                ret = afs_vl_get_capabilities(net, &ac, key, server,
+                err = afs_vl_get_capabilities(net, &ac, key, server,
                                               server_index, true);
-                if (ret != -EINPROGRESS) {
-                        afs_vl_probe_done(server);
-                        return ret;
-                }
+                if (err == -EINPROGRESS)
+                        in_progress = true;
+                else
+                        afs_prioritise_error(_e, err, ac.abort_code);
         }
 
-        return 0;
+        if (!in_progress)
+                afs_vl_probe_done(server);
+        return in_progress;
 }
 
 /*
@@ -169,21 +176,23 @@ int afs_send_vl_probes(struct afs_net *net, struct key *key,
                        struct afs_vlserver_list *vllist)
 {
         struct afs_vlserver *server;
-        int i, ret;
+        struct afs_error e;
+        bool in_progress = false;
+        int i;
 
+        e.error = 0;
+        e.responded = false;
         for (i = 0; i < vllist->nr_servers; i++) {
                 server = vllist->servers[i].server;
                 if (test_bit(AFS_VLSERVER_FL_PROBED, &server->flags))
                         continue;
 
-                if (!test_and_set_bit_lock(AFS_VLSERVER_FL_PROBING, &server->flags)) {
-                        ret = afs_do_probe_vlserver(net, server, key, i);
-                        if (ret)
-                                return ret;
-                }
+                if (!test_and_set_bit_lock(AFS_VLSERVER_FL_PROBING, &server->flags) &&
+                    afs_do_probe_vlserver(net, server, key, i, &e))
+                        in_progress = true;
         }
 
-        return 0;
+        return in_progress ? 0 : e.error;
 }
 
 /*
diff --git a/fs/afs/vl_rotate.c b/fs/afs/vl_rotate.c
index b64a284b99d2..7adde83a0648 100644
--- a/fs/afs/vl_rotate.c
+++ b/fs/afs/vl_rotate.c
@@ -71,8 +71,9 @@ bool afs_select_vlserver(struct afs_vl_cursor *vc)
 {
         struct afs_addr_list *alist;
         struct afs_vlserver *vlserver;
+        struct afs_error e;
         u32 rtt;
-        int error = vc->ac.error, abort_code, i;
+        int error = vc->ac.error, i;
 
         _enter("%lx[%d],%lx[%d],%d,%d",
                vc->untried, vc->index,
@@ -119,8 +120,11 @@ bool afs_select_vlserver(struct afs_vl_cursor *vc)
                         goto failed;
                 }
 
+        case -ERFKILL:
+        case -EADDRNOTAVAIL:
         case -ENETUNREACH:
         case -EHOSTUNREACH:
+        case -EHOSTDOWN:
         case -ECONNREFUSED:
         case -ETIMEDOUT:
         case -ETIME:
@@ -235,50 +239,15 @@ no_more_servers:
         if (vc->flags & AFS_VL_CURSOR_RETRY)
                 goto restart_from_beginning;
 
-        abort_code = 0;
-        error = -EDESTADDRREQ;
+        e.error = -EDESTADDRREQ;
+        e.responded = false;
         for (i = 0; i < vc->server_list->nr_servers; i++) {
                 struct afs_vlserver *s = vc->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:
         vc->error = error;
 failed:
@@ -341,6 +310,7 @@ int afs_end_vlserver_operation(struct afs_vl_cursor *vc)
         struct afs_net *net = vc->cell->net;
 
         if (vc->error == -EDESTADDRREQ ||
+            vc->error == -EADDRNOTAVAIL ||
             vc->error == -ENETUNREACH ||
             vc->error == -EHOSTUNREACH)
                 afs_vl_dump_edestaddrreq(vc);