commit ded9d2d5e247dc4d141c01bc8dc99d6ec832f9e8
author Paolo Bonzini <pbonzini@redhat.com> Fri Feb 08 14:06:13 2013 +0100
committer Kevin Wolf <kwolf@redhat.com> Fri Feb 22 21:29:43 2013 +0100
tree 06aefc8a40e77716dbc1df71f0c2be60b6ab406d
parent a9384aff5315e7568b6ebc171f4a482e01f06526

qemu-nbd: add --discard option

Similar to --cache and --aio, this option mimics the discard suboption
of "-drive".

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

qemu-nbd.c

diff --git a/qemu-nbd.c b/qemu-nbd.c
index 0a6091b..e7268d0 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -33,9 +33,10 @@
 #include <libgen.h>
 #include <pthread.h>
 
-#define SOCKET_PATH         "/var/lock/qemu-nbd-%s"
-#define QEMU_NBD_OPT_CACHE  1
-#define QEMU_NBD_OPT_AIO    2
+#define SOCKET_PATH          "/var/lock/qemu-nbd-%s"
+#define QEMU_NBD_OPT_CACHE   1
+#define QEMU_NBD_OPT_AIO     2
+#define QEMU_NBD_OPT_DISCARD 3
 
 static NBDExport *exp;
 static int verbose;
@@ -330,6 +331,7 @@
 #ifdef CONFIG_LINUX_AIO
         { "aio", 1, NULL, QEMU_NBD_OPT_AIO },
 #endif
+        { "discard", 1, NULL, QEMU_NBD_OPT_DISCARD },
         { "shared", 1, NULL, 'e' },
         { "persistent", 0, NULL, 't' },
         { "verbose", 0, NULL, 'v' },
@@ -344,6 +346,7 @@
     int ret;
     int fd;
     bool seen_cache = false;
+    bool seen_discard = false;
 #ifdef CONFIG_LINUX_AIO
     bool seen_aio = false;
 #endif
@@ -389,6 +392,15 @@
             }
             break;
 #endif
+        case QEMU_NBD_OPT_DISCARD:
+            if (seen_discard) {
+                errx(EXIT_FAILURE, "--discard can only be specified once");
+            }
+            seen_discard = true;
+            if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
+                errx(EXIT_FAILURE, "Invalid discard mode `%s'", optarg);
+            }
+            break;
         case 'b':
             bindto = optarg;
             break;