afs: Use the fs operation ops to handle FetchData completion

Use the 'success' and 'aborted' afs_operations_ops methods and add a
'failed' method to handle the completion of an AFS.FetchData,
AFS.FetchData64 or YFS.FetchData64 RPC operation rather than directly
calling the done func pointed to by the afs_read struct from the call
delivery handler.

This means the done function will be called back on error also, not just on
successful completion.

This allows motion towards asynchronous data reception on data fetch calls
and allows any error to be handed off to the fscache read helper in the
same place as a successful completion.

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-By: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/160588541471.3465195.8807019223378490810.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161118157260.1232039.6549085372718234792.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161161052647.2537118.12922380836599003659.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161340417106.1303470.3502017303898569631.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/161539560673.286939.391310781674212229.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/161653816367.2770958.5856904574822446404.stgit@warthog.procyon.org.uk/ # v5
Link: https://lore.kernel.org/r/161789099994.6155.473719823490561190.stgit@warthog.procyon.org.uk/ # v6

Author: dhowells

fs/afs/file.c

@@ -254,6 +254,19 @@ void afs_put_read(struct afs_read *req)
 	}
 }
 
+static void afs_fetch_data_notify(struct afs_operation *op)
+{
+	struct afs_read *req = op->fetch.req;
+	int error = op->error;
+
+	if (error == -ECONNABORTED)
+		error = afs_abort_to_error(op->ac.abort_code);
+	req->error = error;
+
+	if (req->done)
+		req->done(req);
+}
+
 static void afs_fetch_data_success(struct afs_operation *op)
 {
 	struct afs_vnode *vnode = op->file[0].vnode;
@@ -262,6 +275,7 @@ static void afs_fetch_data_success(struct afs_operation *op)
 	afs_vnode_commit_status(op, &op->file[0]);
 	afs_stat_v(vnode, n_fetches);
 	atomic_long_add(op->fetch.req->actual_len, &op->net->n_fetch_bytes);
+	afs_fetch_data_notify(op);
 }
 
 static void afs_fetch_data_put(struct afs_operation *op)
@@ -275,6 +289,7 @@ static const struct afs_operation_ops afs_fetch_data_operation = {
 	.issue_yfs_rpc	= yfs_fs_fetch_data,
 	.success	= afs_fetch_data_success,
 	.aborted	= afs_check_for_remote_deletion,
+	.failed		= afs_fetch_data_notify,
 	.put		= afs_fetch_data_put,
 };
 

fs/afs/fs_operation.c

@@ -198,8 +198,10 @@ void afs_wait_for_operation(struct afs_operation *op)
 	case -ECONNABORTED:
 		if (op->ops->aborted)
 			op->ops->aborted(op);
-		break;
+		fallthrough;
 	default:
+		if (op->ops->failed)
+			op->ops->failed(op);
 		break;
 	}
 

fs/afs/fsclient.c

@@ -392,9 +392,6 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call)
 		break;
 	}
 
-	if (req->done)
-		req->done(req);
-
 	_leave(" = 0 [done]");
 	return 0;
 }

fs/afs/internal.h

@@ -742,6 +742,7 @@ struct afs_operation_ops {
 	void (*issue_yfs_rpc)(struct afs_operation *op);
 	void (*success)(struct afs_operation *op);
 	void (*aborted)(struct afs_operation *op);
+	void (*failed)(struct afs_operation *op);
 	void (*edit_dir)(struct afs_operation *op);
 	void (*put)(struct afs_operation *op);
 };

fs/afs/yfsclient.c

@@ -449,9 +449,6 @@ static int yfs_deliver_fs_fetch_data64(struct afs_call *call)
 		break;
 	}
 
-	if (req->done)
-		req->done(req);
-
 	_leave(" = 0 [done]");
 	return 0;
 }