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, 27 insertions, 18 deletions

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;
 }
 
 /*