qemu-kvm/SOURCES/kvm-nbd-server-Mark-negotiation-functions-as-coroutine_f.patch

From af6f51ad3482513e3ac047eb203f9dc623d47088 Mon Sep 17 00:00:00 2001
From: Eric Blake <eblake@redhat.com>
Date: Mon, 8 Apr 2024 11:00:44 -0500
Subject: [PATCH 2/2] nbd/server: Mark negotiation functions as coroutine_fn

RH-Author: Eric Blake <eblake@redhat.com>
RH-MergeRequest: 239: avoid destination hang on NBD+TLS storage migration
RH-Jira: RHEL-33440
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Commit: [2/2] acf61b854f80365993d24bcd1d110ed3518b22fa (ebblake/centos-qemu-kvm)

nbd_negotiate() is already marked coroutine_fn.  And given the fix in
the previous patch to have nbd_negotiate_handle_starttls not create
and wait on a g_main_loop (as that would violate coroutine
constraints), it is worth marking the rest of the related static
functions reachable only during option negotiation as also being
coroutine_fn.

Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-ID: <20240408160214.1200629-6-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
[eblake: drop one spurious coroutine_fn marking]
Signed-off-by: Eric Blake <eblake@redhat.com>

Jira: https://issues.redhat.com/browse/RHEL-33440
(cherry picked from commit 4fa333e08dd96395a99ea8dd9e4c73a29dd23344)
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 nbd/server.c | 102 +++++++++++++++++++++++++++++----------------------
 1 file changed, 59 insertions(+), 43 deletions(-)

diff --git a/nbd/server.c b/nbd/server.c
index 98ae0e1632..892797bb11 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -195,8 +195,9 @@ static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option,
 
 /* Send a reply header, including length, but no payload.
  * Return -errno on error, 0 on success. */
-static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type,
-                                      uint32_t len, Error **errp)
+static coroutine_fn int
+nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type,
+                           uint32_t len, Error **errp)
 {
     NBDOptionReply rep;
 
@@ -211,15 +212,15 @@ static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type,
 
 /* Send a reply header with default 0 length.
  * Return -errno on error, 0 on success. */
-static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type,
-                                  Error **errp)
+static coroutine_fn int
+nbd_negotiate_send_rep(NBDClient *client, uint32_t type, Error **errp)
 {
     return nbd_negotiate_send_rep_len(client, type, 0, errp);
 }
 
 /* Send an error reply.
  * Return -errno on error, 0 on success. */
-static int G_GNUC_PRINTF(4, 0)
+static coroutine_fn int G_GNUC_PRINTF(4, 0)
 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type,
                             Error **errp, const char *fmt, va_list va)
 {
@@ -259,7 +260,7 @@ nbd_sanitize_name(const char *name)
 
 /* Send an error reply.
  * Return -errno on error, 0 on success. */
-static int G_GNUC_PRINTF(4, 5)
+static coroutine_fn int G_GNUC_PRINTF(4, 5)
 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type,
                            Error **errp, const char *fmt, ...)
 {
@@ -275,7 +276,7 @@ nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type,
 /* Drop remainder of the current option, and send a reply with the
  * given error type and message. Return -errno on read or write
  * failure; or 0 if connection is still live. */
-static int G_GNUC_PRINTF(4, 0)
+static coroutine_fn int G_GNUC_PRINTF(4, 0)
 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp,
               const char *fmt, va_list va)
 {
@@ -288,7 +289,7 @@ nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp,
     return ret;
 }
 
-static int G_GNUC_PRINTF(4, 5)
+static coroutine_fn int G_GNUC_PRINTF(4, 5)
 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp,
              const char *fmt, ...)
 {
@@ -302,7 +303,7 @@ nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp,
     return ret;
 }
 
-static int G_GNUC_PRINTF(3, 4)
+static coroutine_fn int G_GNUC_PRINTF(3, 4)
 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...)
 {
     int ret;
@@ -319,8 +320,9 @@ nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...)
  * If @check_nul, require that no NUL bytes appear in buffer.
  * Return -errno on I/O error, 0 if option was completely handled by
  * sending a reply about inconsistent lengths, or 1 on success. */
-static int nbd_opt_read(NBDClient *client, void *buffer, size_t size,
-                        bool check_nul, Error **errp)
+static coroutine_fn int
+nbd_opt_read(NBDClient *client, void *buffer, size_t size,
+             bool check_nul, Error **errp)
 {
     if (size > client->optlen) {
         return nbd_opt_invalid(client, errp,
@@ -343,7 +345,8 @@ static int nbd_opt_read(NBDClient *client, void *buffer, size_t size,
 /* Drop size bytes from the unparsed payload of the current option.
  * Return -errno on I/O error, 0 if option was completely handled by
  * sending a reply about inconsistent lengths, or 1 on success. */
-static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp)
+static coroutine_fn int
+nbd_opt_skip(NBDClient *client, size_t size, Error **errp)
 {
     if (size > client->optlen) {
         return nbd_opt_invalid(client, errp,
@@ -366,8 +369,9 @@ static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp)
  * Return -errno on I/O error, 0 if option was completely handled by
  * sending a reply about inconsistent lengths, or 1 on success.
  */
-static int nbd_opt_read_name(NBDClient *client, char **name, uint32_t *length,
-                             Error **errp)
+static coroutine_fn int
+nbd_opt_read_name(NBDClient *client, char **name, uint32_t *length,
+                  Error **errp)
 {
     int ret;
     uint32_t len;
@@ -402,8 +406,8 @@ static int nbd_opt_read_name(NBDClient *client, char **name, uint32_t *length,
 
 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
  * Return -errno on error, 0 on success. */
-static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp,
-                                       Error **errp)
+static coroutine_fn int
+nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp, Error **errp)
 {
     ERRP_GUARD();
     size_t name_len, desc_len;
@@ -444,7 +448,8 @@ static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp,
 
 /* Process the NBD_OPT_LIST command, with a potential series of replies.
  * Return -errno on error, 0 on success. */
-static int nbd_negotiate_handle_list(NBDClient *client, Error **errp)
+static coroutine_fn int
+nbd_negotiate_handle_list(NBDClient *client, Error **errp)
 {
     NBDExport *exp;
     assert(client->opt == NBD_OPT_LIST);
@@ -459,7 +464,8 @@ static int nbd_negotiate_handle_list(NBDClient *client, Error **errp)
     return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
 }
 
-static void nbd_check_meta_export(NBDClient *client, NBDExport *exp)
+static coroutine_fn void
+nbd_check_meta_export(NBDClient *client, NBDExport *exp)
 {
     if (exp != client->contexts.exp) {
         client->contexts.count = 0;
@@ -468,8 +474,9 @@ static void nbd_check_meta_export(NBDClient *client, NBDExport *exp)
 
 /* Send a reply to NBD_OPT_EXPORT_NAME.
  * Return -errno on error, 0 on success. */
-static int nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes,
-                                            Error **errp)
+static coroutine_fn int
+nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes,
+                                 Error **errp)
 {
     ERRP_GUARD();
     g_autofree char *name = NULL;
@@ -536,9 +543,9 @@ static int nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes,
 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes.
  * The buffer does NOT include the info type prefix.
  * Return -errno on error, 0 if ready to send more. */
-static int nbd_negotiate_send_info(NBDClient *client,
-                                   uint16_t info, uint32_t length, void *buf,
-                                   Error **errp)
+static coroutine_fn int
+nbd_negotiate_send_info(NBDClient *client, uint16_t info, uint32_t length,
+                        void *buf, Error **errp)
 {
     int rc;
 
@@ -565,7 +572,8 @@ static int nbd_negotiate_send_info(NBDClient *client,
  * -errno  transmission error occurred or @fatal was requested, errp is set
  * 0       error message successfully sent to client, errp is not set
  */
-static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp)
+static coroutine_fn int
+nbd_reject_length(NBDClient *client, bool fatal, Error **errp)
 {
     int ret;
 
@@ -583,7 +591,8 @@ static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp)
 /* Handle NBD_OPT_INFO and NBD_OPT_GO.
  * Return -errno on error, 0 if ready for next option, and 1 to move
  * into transmission phase.  */
-static int nbd_negotiate_handle_info(NBDClient *client, Error **errp)
+static coroutine_fn int
+nbd_negotiate_handle_info(NBDClient *client, Error **errp)
 {
     int rc;
     g_autofree char *name = NULL;
@@ -755,7 +764,8 @@ struct NBDTLSServerHandshakeData {
     Coroutine *co;
 };
 
-static void nbd_server_tls_handshake(QIOTask *task, void *opaque)
+static void
+nbd_server_tls_handshake(QIOTask *task, void *opaque)
 {
     struct NBDTLSServerHandshakeData *data = opaque;
 
@@ -768,8 +778,8 @@ static void nbd_server_tls_handshake(QIOTask *task, void *opaque)
 
 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the
  * new channel for all further (now-encrypted) communication. */
-static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
-                                                 Error **errp)
+static coroutine_fn QIOChannel *
+nbd_negotiate_handle_starttls(NBDClient *client, Error **errp)
 {
     QIOChannel *ioc;
     QIOChannelTLS *tioc;
@@ -821,10 +831,9 @@ static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
  *
  * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead.
  */
-static int nbd_negotiate_send_meta_context(NBDClient *client,
-                                           const char *context,
-                                           uint32_t context_id,
-                                           Error **errp)
+static coroutine_fn int
+nbd_negotiate_send_meta_context(NBDClient *client, const char *context,
+                                uint32_t context_id, Error **errp)
 {
     NBDOptionReplyMetaContext opt;
     struct iovec iov[] = {
@@ -849,8 +858,9 @@ static int nbd_negotiate_send_meta_context(NBDClient *client,
  * Return true if @query matches @pattern, or if @query is empty when
  * the @client is performing _LIST_.
  */
-static bool nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern,
-                                      const char *query)
+static coroutine_fn bool
+nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern,
+                          const char *query)
 {
     if (!*query) {
         trace_nbd_negotiate_meta_query_parse("empty");
@@ -867,7 +877,8 @@ static bool nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern,
 /*
  * Return true and adjust @str in place if it begins with @prefix.
  */
-static bool nbd_strshift(const char **str, const char *prefix)
+static coroutine_fn bool
+nbd_strshift(const char **str, const char *prefix)
 {
     size_t len = strlen(prefix);
 
@@ -883,8 +894,9 @@ static bool nbd_strshift(const char **str, const char *prefix)
  * Handle queries to 'base' namespace. For now, only the base:allocation
  * context is available.  Return true if @query has been handled.
  */
-static bool nbd_meta_base_query(NBDClient *client, NBDMetaContexts *meta,
-                                const char *query)
+static coroutine_fn bool
+nbd_meta_base_query(NBDClient *client, NBDMetaContexts *meta,
+                    const char *query)
 {
     if (!nbd_strshift(&query, "base:")) {
         return false;
@@ -903,8 +915,9 @@ static bool nbd_meta_base_query(NBDClient *client, NBDMetaContexts *meta,
  * and qemu:allocation-depth contexts are available.  Return true if @query
  * has been handled.
  */
-static bool nbd_meta_qemu_query(NBDClient *client, NBDMetaContexts *meta,
-                                const char *query)
+static coroutine_fn bool
+nbd_meta_qemu_query(NBDClient *client, NBDMetaContexts *meta,
+                    const char *query)
 {
     size_t i;
 
@@ -968,8 +981,9 @@ static bool nbd_meta_qemu_query(NBDClient *client, NBDMetaContexts *meta,
  *
  * Return -errno on I/O error, 0 if option was completely handled by
  * sending a reply about inconsistent lengths, or 1 on success. */
-static int nbd_negotiate_meta_query(NBDClient *client,
-                                    NBDMetaContexts *meta, Error **errp)
+static coroutine_fn int
+nbd_negotiate_meta_query(NBDClient *client,
+                         NBDMetaContexts *meta, Error **errp)
 {
     int ret;
     g_autofree char *query = NULL;
@@ -1008,7 +1022,8 @@ static int nbd_negotiate_meta_query(NBDClient *client,
  * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT
  *
  * Return -errno on I/O error, or 0 if option was completely handled. */
-static int nbd_negotiate_meta_queries(NBDClient *client, Error **errp)
+static coroutine_fn int
+nbd_negotiate_meta_queries(NBDClient *client, Error **errp)
 {
     int ret;
     g_autofree char *export_name = NULL;
@@ -1136,7 +1151,8 @@ static int nbd_negotiate_meta_queries(NBDClient *client, Error **errp)
  * 1       if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
  *         errp is not set
  */
-static int nbd_negotiate_options(NBDClient *client, Error **errp)
+static coroutine_fn int
+nbd_negotiate_options(NBDClient *client, Error **errp)
 {
     uint32_t flags;
     bool fixedNewstyle = false;
-- 
2.39.3