[PATCH v6 10/11] nbd: introduce ERRP_AUTO_PROPAGATE

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

If we want to add some info to errp (by error_prepend() or
error_append_hint()), we must use the ERRP_AUTO_PROPAGATE macro.
Otherwise, this info will not be added when errp == &error_fatal
(the program will exit prior to the error_append_hint() or
error_prepend() call).  Fix such cases.

If we want to check error after errp-function call, we need to
introduce local_err and then propagate it to errp. Instead, use
ERRP_AUTO_PROPAGATE macro, benefits are:
1. No need of explicit error_propagate call
2. No need of explicit local_err variable: use errp directly
3. ERRP_AUTO_PROPAGATE leaves errp as is if it's not NULL or
   &error_fatal, this means that we don't break error_abort
   (we'll abort on error_set, not on error_propagate)

This commit is generated by command

    sed -n '/^Network Block Device (NBD)$/,/^$/{s/^F: //p}' \
        MAINTAINERS | \
    xargs git ls-files | grep '\.[hc]$' | \
    xargs spatch \
        --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
        --macro-file scripts/cocci-macro-file.h \
        --in-place --no-show-diff --max-width 80

Reported-by: Kevin Wolf <kwolf@redhat.com>
Reported-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 include/block/nbd.h |  1 +
 block/nbd.c         | 49 +++++++++++++++++++++------------------------
 nbd/client.c        |  5 +++++
 nbd/server.c        |  5 +++++
 4 files changed, 34 insertions(+), 26 deletions(-)

diff --git a/include/block/nbd.h b/include/block/nbd.h
index 7f46932d80..4ab8d917ed 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -360,6 +360,7 @@ void nbd_server_start(SocketAddress *addr, const char *tls_creds,
 static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size,
                            const char *desc, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     int ret = qio_channel_read_all(ioc, buffer, size, errp) < 0 ? -EIO : 0;
 
     if (ret < 0) {
diff --git a/block/nbd.c b/block/nbd.c
index d085554f21..9701ccf887 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -990,10 +990,10 @@ static int nbd_co_receive_cmdread_reply(BDRVNBDState *s, uint64_t handle,
                                         uint64_t offset, QEMUIOVector *qiov,
                                         int *request_ret, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     NBDReplyChunkIter iter;
     NBDReply reply;
     void *payload = NULL;
-    Error *local_err = NULL;
 
     NBD_FOREACH_REPLY_CHUNK(s, iter, handle, s->info.structured_reply,
                             qiov, &reply, &payload)
@@ -1012,20 +1012,20 @@ static int nbd_co_receive_cmdread_reply(BDRVNBDState *s, uint64_t handle,
             break;
         case NBD_REPLY_TYPE_OFFSET_HOLE:
             ret = nbd_parse_offset_hole_payload(s, &reply.structured, payload,
-                                                offset, qiov, &local_err);
+                                                offset, qiov, errp);
             if (ret < 0) {
                 nbd_channel_error(s, ret);
-                nbd_iter_channel_error(&iter, ret, &local_err);
+                nbd_iter_channel_error(&iter, ret, errp);
             }
             break;
         default:
             if (!nbd_reply_type_is_error(chunk->type)) {
                 /* not allowed reply type */
                 nbd_channel_error(s, -EINVAL);
-                error_setg(&local_err,
+                error_setg(errp,
                            "Unexpected reply type: %d (%s) for CMD_READ",
                            chunk->type, nbd_reply_type_lookup(chunk->type));
-                nbd_iter_channel_error(&iter, -EINVAL, &local_err);
+                nbd_iter_channel_error(&iter, -EINVAL, errp);
             }
         }
 
@@ -1043,10 +1043,10 @@ static int nbd_co_receive_blockstatus_reply(BDRVNBDState *s,
                                             NBDExtent *extent,
                                             int *request_ret, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     NBDReplyChunkIter iter;
     NBDReply reply;
     void *payload = NULL;
-    Error *local_err = NULL;
     bool received = false;
 
     assert(!extent->length);
@@ -1060,27 +1060,27 @@ static int nbd_co_receive_blockstatus_reply(BDRVNBDState *s,
         case NBD_REPLY_TYPE_BLOCK_STATUS:
             if (received) {
                 nbd_channel_error(s, -EINVAL);
-                error_setg(&local_err, "Several BLOCK_STATUS chunks in reply");
-                nbd_iter_channel_error(&iter, -EINVAL, &local_err);
+                error_setg(errp, "Several BLOCK_STATUS chunks in reply");
+                nbd_iter_channel_error(&iter, -EINVAL, errp);
             }
             received = true;
 
             ret = nbd_parse_blockstatus_payload(s, &reply.structured,
                                                 payload, length, extent,
-                                                &local_err);
+                                                errp);
             if (ret < 0) {
                 nbd_channel_error(s, ret);
-                nbd_iter_channel_error(&iter, ret, &local_err);
+                nbd_iter_channel_error(&iter, ret, errp);
             }
             break;
         default:
             if (!nbd_reply_type_is_error(chunk->type)) {
                 nbd_channel_error(s, -EINVAL);
-                error_setg(&local_err,
+                error_setg(errp,
                            "Unexpected reply type: %d (%s) "
                            "for CMD_BLOCK_STATUS",
                            chunk->type, nbd_reply_type_lookup(chunk->type));
-                nbd_iter_channel_error(&iter, -EINVAL, &local_err);
+                nbd_iter_channel_error(&iter, -EINVAL, errp);
             }
         }
 
@@ -1089,8 +1089,8 @@ static int nbd_co_receive_blockstatus_reply(BDRVNBDState *s,
     }
 
     if (!extent->length && !iter.request_ret) {
-        error_setg(&local_err, "Server did not reply with any status extents");
-        nbd_iter_channel_error(&iter, -EIO, &local_err);
+        error_setg(errp, "Server did not reply with any status extents");
+        nbd_iter_channel_error(&iter, -EIO, errp);
     }
 
     error_propagate(errp, iter.err);
@@ -1385,16 +1385,15 @@ static void nbd_client_close(BlockDriverState *bs)
 static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr,
                                                   Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     QIOChannelSocket *sioc;
-    Error *local_err = NULL;
 
     sioc = qio_channel_socket_new();
     qio_channel_set_name(QIO_CHANNEL(sioc), "nbd-client");
 
-    qio_channel_socket_connect_sync(sioc, saddr, &local_err);
-    if (local_err) {
+    qio_channel_socket_connect_sync(sioc, saddr, errp);
+    if (*errp) {
         object_unref(OBJECT(sioc));
-        error_propagate(errp, local_err);
         return NULL;
     }
 
@@ -1698,10 +1697,10 @@ static bool nbd_process_legacy_socket_options(QDict *output_options,
 static SocketAddress *nbd_config(BDRVNBDState *s, QDict *options,
                                  Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     SocketAddress *saddr = NULL;
     QDict *addr = NULL;
     Visitor *iv = NULL;
-    Error *local_err = NULL;
 
     qdict_extract_subqdict(options, &addr, "server.");
     if (!qdict_size(addr)) {
@@ -1714,9 +1713,8 @@ static SocketAddress *nbd_config(BDRVNBDState *s, QDict *options,
         goto done;
     }
 
-    visit_type_SocketAddress(iv, NULL, &saddr, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    visit_type_SocketAddress(iv, NULL, &saddr, errp);
+    if (*errp) {
         goto done;
     }
 
@@ -1809,15 +1807,14 @@ static QemuOptsList nbd_runtime_opts = {
 static int nbd_process_options(BlockDriverState *bs, QDict *options,
                                Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     BDRVNBDState *s = bs->opaque;
     QemuOpts *opts;
-    Error *local_err = NULL;
     int ret = -EINVAL;
 
     opts = qemu_opts_create(&nbd_runtime_opts, NULL, 0, &error_abort);
-    qemu_opts_absorb_qdict(opts, options, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    qemu_opts_absorb_qdict(opts, options, errp);
+    if (*errp) {
         goto error;
     }
 
diff --git a/nbd/client.c b/nbd/client.c
index ba173108ba..e258ef3f7e 100644
--- a/nbd/client.c
+++ b/nbd/client.c
@@ -68,6 +68,7 @@ static int nbd_send_option_request(QIOChannel *ioc, uint32_t opt,
                                    uint32_t len, const char *data,
                                    Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     NBDOption req;
     QEMU_BUILD_BUG_ON(sizeof(req) != 16);
 
@@ -153,6 +154,7 @@ static int nbd_receive_option_reply(QIOChannel *ioc, uint32_t opt,
 static int nbd_handle_reply_err(QIOChannel *ioc, NBDOptionReply *reply,
                                 bool strict, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     g_autofree char *msg = NULL;
 
     if (!(reply->type & (1 << 31))) {
@@ -337,6 +339,7 @@ static int nbd_receive_list(QIOChannel *ioc, char **name, char **description,
 static int nbd_opt_info_or_go(QIOChannel *ioc, uint32_t opt,
                               NBDExportInfo *info, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     NBDOptionReply reply;
     uint32_t len = strlen(info->name);
     uint16_t type;
@@ -882,6 +885,7 @@ static int nbd_start_negotiate(AioContext *aio_context, QIOChannel *ioc,
                                bool structured_reply, bool *zeroes,
                                Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     uint64_t magic;
 
     trace_nbd_start_negotiate(tlscreds, hostname ? hostname : "<null>");
@@ -1017,6 +1021,7 @@ int nbd_receive_negotiate(AioContext *aio_context, QIOChannel *ioc,
                           const char *hostname, QIOChannel **outioc,
                           NBDExportInfo *info, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     int result;
     bool zeroes;
     bool base_allocation = info->base_allocation;
diff --git a/nbd/server.c b/nbd/server.c
index 24ebc1a805..19de61a23e 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -211,6 +211,7 @@ static int GCC_FMT_ATTR(4, 0)
 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type,
                             Error **errp, const char *fmt, va_list va)
 {
+    ERRP_AUTO_PROPAGATE();
     g_autofree char *msg = NULL;
     int ret;
     size_t len;
@@ -369,6 +370,7 @@ static int nbd_opt_read_name(NBDClient *client, char **name, uint32_t *length,
 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp,
                                        Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     size_t name_len, desc_len;
     uint32_t len;
     const char *name = exp->name ? exp->name : "";
@@ -432,6 +434,7 @@ static void nbd_check_meta_export(NBDClient *client)
 static int nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes,
                                             Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     g_autofree char *name = NULL;
     char buf[NBD_REPLY_EXPORT_NAME_SIZE] = "";
     size_t len;
@@ -1272,6 +1275,7 @@ static int nbd_negotiate_options(NBDClient *client, Error **errp)
  */
 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = "";
     int ret;
 
@@ -1646,6 +1650,7 @@ void nbd_export_close(NBDExport *exp)
 
 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) {
         nbd_export_close(exp);
         return;
-- 
2.21.0