nbd: Improve per-export flag handling in server

[thirdparty/qemu.git] / nbd / server.c

diff --git a/nbd/server.c b/nbd/server.c
index 74d205812feee0c20300aaca4bed7d3163eeb9c6..d5078f7468af3507a6454fe933d61946d42f1d6f 100644 (file)
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -419,14 +419,14 @@ static void nbd_check_meta_export(NBDClient *client)
 
 /* Send a reply to NBD_OPT_EXPORT_NAME.
  * Return -errno on error, 0 on success. */
-static int nbd_negotiate_handle_export_name(NBDClient *client,
-                                            uint16_t myflags, bool no_zeroes,
+static int nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes,
                                             Error **errp)
 {
     char name[NBD_MAX_NAME_SIZE + 1];
     char buf[NBD_REPLY_EXPORT_NAME_SIZE] = "";
     size_t len;
     int ret;
+    uint16_t myflags;
 
     /* Client sends:
         [20 ..  xx]   export name (length bytes)
@@ -454,10 +454,13 @@ static int nbd_negotiate_handle_export_name(NBDClient *client,
         return -EINVAL;
     }
 
-    trace_nbd_negotiate_new_style_size_flags(client->exp->size,
-                                             client->exp->nbdflags | myflags);
+    myflags = client->exp->nbdflags;
+    if (client->structured_reply) {
+        myflags |= NBD_FLAG_SEND_DF;
+    }
+    trace_nbd_negotiate_new_style_size_flags(client->exp->size, myflags);
     stq_be_p(buf, client->exp->size);
-    stw_be_p(buf + 8, client->exp->nbdflags | myflags);
+    stw_be_p(buf + 8, myflags);
     len = no_zeroes ? 10 : sizeof(buf);
     ret = nbd_write(client->ioc, buf, len, errp);
     if (ret < 0) {
@@ -522,8 +525,7 @@ 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, uint16_t myflags,
-                                     Error **errp)
+static int nbd_negotiate_handle_info(NBDClient *client, Error **errp)
 {
     int rc;
     char name[NBD_MAX_NAME_SIZE + 1];
@@ -536,6 +538,7 @@ static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags,
     uint32_t sizes[3];
     char buf[sizeof(uint64_t) + sizeof(uint16_t)];
     uint32_t check_align = 0;
+    uint16_t myflags;
 
     /* Client sends:
         4 bytes: L, name length (can be 0)
@@ -633,10 +636,13 @@ static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags,
     }
 
     /* Send NBD_INFO_EXPORT always */
-    trace_nbd_negotiate_new_style_size_flags(exp->size,
-                                             exp->nbdflags | myflags);
+    myflags = exp->nbdflags;
+    if (client->structured_reply) {
+        myflags |= NBD_FLAG_SEND_DF;
+    }
+    trace_nbd_negotiate_new_style_size_flags(exp->size, myflags);
     stq_be_p(buf, exp->size);
-    stw_be_p(buf + 8, exp->nbdflags | myflags);
+    stw_be_p(buf + 8, myflags);
     rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT,
                                  sizeof(buf), buf, errp);
     if (rc < 0) {
@@ -1033,8 +1039,7 @@ static int nbd_negotiate_meta_queries(NBDClient *client,
  * 1       if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
  *         errp is not set
  */
-static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
-                                 Error **errp)
+static int nbd_negotiate_options(NBDClient *client, Error **errp)
 {
     uint32_t flags;
     bool fixedNewstyle = false;
@@ -1168,13 +1173,12 @@ static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
                 return 1;
 
             case NBD_OPT_EXPORT_NAME:
-                return nbd_negotiate_handle_export_name(client,
-                                                        myflags, no_zeroes,
+                return nbd_negotiate_handle_export_name(client, no_zeroes,
                                                         errp);
 
             case NBD_OPT_INFO:
             case NBD_OPT_GO:
-                ret = nbd_negotiate_handle_info(client, myflags, errp);
+                ret = nbd_negotiate_handle_info(client, errp);
                 if (ret == 1) {
                     assert(option == NBD_OPT_GO);
                     return 0;
@@ -1205,7 +1209,6 @@ static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
                 } else {
                     ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
                     client->structured_reply = true;
-                    myflags |= NBD_FLAG_SEND_DF;
                 }
                 break;
 
@@ -1228,8 +1231,7 @@ static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
              */
             switch (option) {
             case NBD_OPT_EXPORT_NAME:
-                return nbd_negotiate_handle_export_name(client,
-                                                        myflags, no_zeroes,
+                return nbd_negotiate_handle_export_name(client, no_zeroes,
                                                         errp);
 
             default:
@@ -1255,9 +1257,6 @@ static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
 {
     char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = "";
     int ret;
-    const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
-                              NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA |
-                              NBD_FLAG_SEND_WRITE_ZEROES | NBD_FLAG_SEND_CACHE);
 
     /* Old style negotiation header, no room for options
         [ 0 ..   7]   passwd       ("NBDMAGIC")
@@ -1285,7 +1284,7 @@ static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
         error_prepend(errp, "write failed: ");
         return -EINVAL;
     }
-    ret = nbd_negotiate_options(client, myflags, errp);
+    ret = nbd_negotiate_options(client, errp);
     if (ret != 0) {
         if (ret < 0) {
             error_prepend(errp, "option negotiation failed: ");
@@ -1457,7 +1456,7 @@ static void nbd_eject_notifier(Notifier *n, void *data)
 
 NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset,
                           uint64_t size, const char *name, const char *desc,
-                          const char *bitmap, uint16_t nbdflags, bool shared,
+                          const char *bitmap, bool readonly, bool shared,
                           void (*close)(NBDExport *), bool writethrough,
                           BlockBackend *on_eject_blk, Error **errp)
 {
@@ -1481,10 +1480,8 @@ NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset,
     /* Don't allow resize while the NBD server is running, otherwise we don't
      * care what happens with the node. */
     perm = BLK_PERM_CONSISTENT_READ;
-    if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) {
+    if (!readonly) {
         perm |= BLK_PERM_WRITE;
-    } else if (shared) {
-        nbdflags |= NBD_FLAG_CAN_MULTI_CONN;
     }
     blk = blk_new(bdrv_get_aio_context(bs), perm,
                   BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
@@ -1503,7 +1500,16 @@ NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset,
     exp->dev_offset = dev_offset;
     exp->name = g_strdup(name);
     exp->description = g_strdup(desc);
-    exp->nbdflags = nbdflags;
+    exp->nbdflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_FLUSH |
+                     NBD_FLAG_SEND_FUA | NBD_FLAG_SEND_CACHE);
+    if (readonly) {
+        exp->nbdflags |= NBD_FLAG_READ_ONLY;
+        if (shared) {
+            exp->nbdflags |= NBD_FLAG_CAN_MULTI_CONN;
+        }
+    } else {
+        exp->nbdflags |= NBD_FLAG_SEND_TRIM | NBD_FLAG_SEND_WRITE_ZEROES;
+    }
     assert(size <= INT64_MAX - dev_offset);
     exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE);
 
@@ -1528,7 +1534,7 @@ NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset,
             goto fail;
         }
 
-        if ((nbdflags & NBD_FLAG_READ_ONLY) && bdrv_is_writable(bs) &&
+        if (readonly && bdrv_is_writable(bs) &&
             bdrv_dirty_bitmap_enabled(bm)) {
             error_setg(errp,
                        "Enabled bitmap '%s' incompatible with readonly export",