afs: Simplify error handling

Simplify error handling a bit by moving it from the afs_addr_cursor struct
to the afs_operation and afs_vl_cursor structs and using the error
prioritisation function for accumulating errors from multiple sources (AFS
tries to rotate between multiple fileservers, some of which may be
inaccessible or in some state of offlinedness).

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

1 files changed, 30 insertions, 28 deletions

diff --git a/fs/afs/rotate.c b/fs/afs/rotate.c
index 965ee8f0804a..a778d53681fe 100644
--- a/fs/afs/rotate.c
+++ b/fs/afs/rotate.c
@@ -112,9 +112,9 @@ bool afs_select_fileserver(struct afs_operation *op)
 	struct afs_addr_list *alist;
 	struct afs_server *server;
 	struct afs_vnode *vnode = op->file[0].vnode;
-	struct afs_error e;
 	unsigned int rtt;
-	int error = op->ac.error, i;
+	s32 abort_code = op->call_abort_code;
+	int error = op->call_error, i;
 
 	op->nr_iterations++;
 
@@ -122,7 +122,7 @@ bool afs_select_fileserver(struct afs_operation *op)
 	       op->debug_id, op->nr_iterations, op->volume->vid,
 	       op->untried, op->index,
 	       op->ac.tried, op->ac.index,
-	       error, op->ac.abort_code);
+	       error, abort_code);
 
 	if (op->flags & AFS_OPERATION_STOP) {
 		_leave(" = f [stopped]");
@@ -133,8 +133,10 @@ bool afs_select_fileserver(struct afs_operation *op)
 		goto start;
 
 	/* Evaluate the result of the previous operation, if there was one. */
-	switch (error) {
+	switch (op->call_error) {
 	case 0:
+		op->cumul_error.responded = true;
+		fallthrough;
 	default:
 		/* Success or local failure.  Stop. */
 		afs_op_set_error(op, error);
@@ -151,7 +153,8 @@ bool afs_select_fileserver(struct afs_operation *op)
 		 * errors instead.  IBM AFS and OpenAFS fileservers, however, do leak
 		 * these abort codes.
 		 */
-		switch (op->ac.abort_code) {
+		op->cumul_error.responded = true;
+		switch (abort_code) {
 		case VNOVOL:
 			/* This fileserver doesn't know about the volume.
 			 * - May indicate that the VL is wrong - retry once and compare
@@ -164,7 +167,7 @@ bool afs_select_fileserver(struct afs_operation *op)
 			 *   (administrative action).
 			 */
 			if (op->flags & AFS_OPERATION_VNOVOL) {
-				op->error = -EREMOTEIO;
+				afs_op_accumulate_error(op, -EREMOTEIO, abort_code);
 				goto next_server;
 			}
 
@@ -188,7 +191,7 @@ bool afs_select_fileserver(struct afs_operation *op)
 			 * it's the fileserver having trouble.
 			 */
 			if (rcu_access_pointer(op->volume->servers) == op->server_list) {
-				op->error = -EREMOTEIO;
+				afs_op_accumulate_error(op, -EREMOTEIO, abort_code);
 				goto next_server;
 			}
 
@@ -201,8 +204,8 @@ bool afs_select_fileserver(struct afs_operation *op)
 		case VONLINE:
 			/* These should not be returned from the fileserver. */
 			pr_warn("Fileserver returned unexpected abort %d\n",
-				op->ac.abort_code);
-			op->error = -EREMOTEIO;
+				abort_code);
+			afs_op_accumulate_error(op, -EREMOTEIO, abort_code);
 			goto next_server;
 
 		case VNOSERVICE:
@@ -233,7 +236,7 @@ bool afs_select_fileserver(struct afs_operation *op)
 			 * VNOSERVICE should be treated as an alias for RX_CALL_TIMEOUT.
 			 */
 		case RX_CALL_TIMEOUT:
-			op->error = -ETIMEDOUT;
+			afs_op_accumulate_error(op, -ETIMEDOUT, abort_code);
 			goto next_server;
 
 		case VSALVAGING: /* This error should not be leaked to cache managers
@@ -248,7 +251,7 @@ bool afs_select_fileserver(struct afs_operation *op)
 			 * days).
 			 */
 			if (!test_and_set_bit(AFS_VOLUME_OFFLINE, &op->volume->flags)) {
-				afs_busy(op->volume, op->ac.abort_code);
+				afs_busy(op->volume, abort_code);
 				clear_bit(AFS_VOLUME_BUSY, &op->volume->flags);
 			}
 			if (op->flags & AFS_OPERATION_NO_VSLEEP) {
@@ -281,7 +284,7 @@ bool afs_select_fileserver(struct afs_operation *op)
 				goto failed;
 			}
 			if (!test_and_set_bit(AFS_VOLUME_BUSY, &op->volume->flags)) {
-				afs_busy(op->volume, op->ac.abort_code);
+				afs_busy(op->volume, abort_code);
 				clear_bit(AFS_VOLUME_OFFLINE, &op->volume->flags);
 			}
 		busy:
@@ -329,7 +332,7 @@ bool afs_select_fileserver(struct afs_operation *op)
 			 * TODO: Retry a few times with sleeps.
 			 */
 			if (rcu_access_pointer(op->volume->servers) == op->server_list) {
-				op->error = -ENOMEDIUM;
+				afs_op_accumulate_error(op, -ENOMEDIUM, abort_code);
 				goto failed;
 			}
 
@@ -337,7 +340,7 @@ bool afs_select_fileserver(struct afs_operation *op)
 
 		case UAEIO:
 		case VIO:
-			op->error = -EREMOTEIO;
+			afs_op_accumulate_error(op, -EREMOTEIO, abort_code);
 			if (op->volume->type != AFSVL_RWVOL)
 				goto next_server;
 			goto failed;
@@ -361,7 +364,7 @@ bool afs_select_fileserver(struct afs_operation *op)
 			goto failed_but_online;
 
 		default:
-			op->error = afs_abort_to_error(op->ac.abort_code);
+			afs_op_accumulate_error(op, error, abort_code);
 		failed_but_online:
 			clear_bit(AFS_VOLUME_OFFLINE, &op->volume->flags);
 			clear_bit(AFS_VOLUME_BUSY, &op->volume->flags);
@@ -380,7 +383,7 @@ bool afs_select_fileserver(struct afs_operation *op)
 	case -EHOSTDOWN:
 	case -ECONNREFUSED:
 		_debug("no conn");
-		op->error = error;
+		afs_op_accumulate_error(op, error, 0);
 		goto iterate_address;
 
 	case -ENETRESET:
@@ -506,6 +509,7 @@ iterate_address:
 	       op->index, op->ac.index, op->ac.alist->nr_addrs,
 	       rxrpc_kernel_remote_addr(op->ac.alist->addrs[op->ac.index].peer));
 
+	op->call_responded = false;
 	_leave(" = t");
 	return true;
 
@@ -543,17 +547,14 @@ no_more_servers:
 	if (op->flags & AFS_OPERATION_VBUSY)
 		goto restart_from_beginning;
 
-	e.error = -EDESTADDRREQ;
-	e.responded = false;
 	for (i = 0; i < op->server_list->nr_servers; i++) {
 		struct afs_server *s = op->server_list->servers[i].server;
 
-		afs_prioritise_error(&e, READ_ONCE(s->probe.error),
-				     s->probe.abort_code);
+		error = READ_ONCE(s->probe.error);
+		if (error < 0)
+			afs_op_accumulate_error(op, error, s->probe.abort_code);
 	}
 
-	error = e.error;
-	op->error = error;
 failed:
 	op->flags |= AFS_OPERATION_STOP;
 	afs_end_cursor(&op->ac);
@@ -576,11 +577,13 @@ void afs_dump_edestaddrreq(const struct afs_operation *op)
 	rcu_read_lock();
 
 	pr_notice("EDESTADDR occurred\n");
-	pr_notice("FC: cbb=%x cbb2=%x fl=%x err=%hd\n",
+	pr_notice("OP: cbb=%x cbb2=%x fl=%x err=%hd\n",
 		  op->file[0].cb_break_before,
-		  op->file[1].cb_break_before, op->flags, op->error);
-	pr_notice("FC: ut=%lx ix=%d ni=%u\n",
+		  op->file[1].cb_break_before, op->flags, op->cumul_error.error);
+	pr_notice("OP: ut=%lx ix=%d ni=%u\n",
 		  op->untried, op->index, op->nr_iterations);
+	pr_notice("OP: call  er=%d ac=%d r=%u\n",
+		  op->call_error, op->call_abort_code, op->call_responded);
 
 	if (op->server_list) {
 		const struct afs_server_list *sl = op->server_list;
@@ -605,8 +608,7 @@ void afs_dump_edestaddrreq(const struct afs_operation *op)
 		}
 	}
 
-	pr_notice("AC: t=%lx ax=%u ac=%d er=%d r=%u ni=%u\n",
-		  op->ac.tried, op->ac.index, op->ac.abort_code, op->ac.error,
-		  op->ac.responded, op->ac.nr_iterations);
+	pr_notice("AC: t=%lx ax=%u ni=%u\n",
+		  op->ac.tried, op->ac.index, op->ac.nr_iterations);
 	rcu_read_unlock();
 }