[Qemu-devel] [PATCH v5 11/27] raw-posix: Implement .bdrv_lockf

[Fam Zheng]

virtlockd in libvirt locks the first byte, we lock byte 1 to avoid
the intervene.

Both file and host device protocols are covered.

Suggested-by: "Daniel P. Berrange" <berra...@redhat.com>
Signed-off-by: Fam Zheng <f...@redhat.com>
---
 block/raw-posix.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/block/raw-posix.c b/block/raw-posix.c
index bb8669f..acd3be2 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -35,6 +35,7 @@
 #include "raw-aio.h"
 #include "qapi/util.h"
 #include "qapi/qmp/qstring.h"
+#include "glib.h"
 
 #if defined(__APPLE__) && (__MACH__)
 #include <paths.h>
@@ -397,6 +398,23 @@ static void raw_attach_aio_context(BlockDriverState *bs,
 #endif
 }
 
+static int raw_lockf(BlockDriverState *bs, BdrvLockfCmd cmd)
+{
+
+    BDRVRawState *s = bs->opaque;
+
+    switch (cmd) {
+    case BDRV_LOCKF_EXCLUSIVE:
+        return qemu_lock_fd(s->fd, 1, 1, true);
+    case BDRV_LOCKF_SHARED:
+        return qemu_lock_fd(s->fd, 1, 1, false);
+    case BDRV_LOCKF_UNLOCK:
+        return qemu_unlock_fd(s->fd, 1, 1);
+    default:
+        abort();
+    }
+}
+
 #ifdef CONFIG_LINUX_AIO
 static int raw_set_aio(LinuxAioState **aio_ctx, int *use_aio, int bdrv_flags)
 {
@@ -1942,6 +1960,8 @@ BlockDriver bdrv_file = {
     .bdrv_detach_aio_context = raw_detach_aio_context,
     .bdrv_attach_aio_context = raw_attach_aio_context,
 
+    .bdrv_lockf = raw_lockf,
+
     .create_opts = &raw_create_opts,
 };
 
@@ -2396,6 +2416,8 @@ static BlockDriver bdrv_host_device = {
 #ifdef __linux__
     .bdrv_aio_ioctl     = hdev_aio_ioctl,
 #endif
+
+    .bdrv_lockf = raw_lockf,
 };
 
 #if defined(__linux__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
-- 
2.8.2