[Qemu-devel] [PATCH v5 03/27] blockdev: Add and parse "lock-mode" option for image locking

[Fam Zheng]

Respect the locking mode from CLI or QMP, and set the open flags
accordingly.

Signed-off-by: Fam Zheng <address@hidden>
---
 blockdev.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/blockdev.c b/blockdev.c
index 1892b8e..0784c4a 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -356,6 +356,7 @@ static void extract_common_blockdev_options(QemuOpts *opts, 
int *bdrv_flags,
     const char *discard;
     Error *local_error = NULL;
     const char *aio;
+    const char *lock_mode;
 
     if (bdrv_flags) {
         if (!qemu_opt_get_bool(opts, "read-only", false)) {
@@ -382,6 +383,18 @@ static void extract_common_blockdev_options(QemuOpts 
*opts, int *bdrv_flags,
                return;
             }
         }
+
+        lock_mode = qemu_opt_get(opts, "lock-mode") ? : "off";
+        if (!strcmp(lock_mode, "exclusive")) {
+            /* Default */
+        } else if (!strcmp(lock_mode, "shared")) {
+            *bdrv_flags |= BDRV_O_SHARED_LOCK;
+        } else if (!strcmp(lock_mode, "off")) {
+            *bdrv_flags |= BDRV_O_NO_LOCK;
+        } else {
+           error_setg(errp, "invalid lock mode");
+           return;
+        }
     }
 
     /* disk I/O throttling */
@@ -4304,6 +4317,11 @@ QemuOptsList qemu_common_drive_opts = {
             .type = QEMU_OPT_BOOL,
             .help = "whether to account for failed I/O operations "
                     "in the statistics",
+        },{
+            .name = "lock-mode",
+            .type = QEMU_OPT_STRING,
+            .help = "how to lock the image (exclusive, shared, off. "
+                    "default: exclusive)",
         },
         { /* end of list */ }
     },
@@ -4333,6 +4351,11 @@ static QemuOptsList qemu_root_bds_opts = {
             .name = "detect-zeroes",
             .type = QEMU_OPT_STRING,
             .help = "try to optimize zero writes (off, on, unmap)",
+        },{
+            .name = "lock-mode",
+            .type = QEMU_OPT_STRING,
+            .help = "how to lock the image (exclusive, shared, off. "
+                    "default: exclusive)",
         },
         { /* end of list */ }
     },
-- 
2.8.2