[Qemu-devel] [PATCH v5] mirror: correct buf_size

[Wen Congyang <wency@cn.fujitsu.com>]

If bus_size is less than 0, the command fails.
If buf_size is 0, use DEFAULT_MIRROR_BUF_SIZE.
If buf_size % granularity is not 0, mirror_free_init() will
do dangerous things.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
---
 block/mirror.c | 11 ++++++++++-
 blockdev.c     |  4 +---
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/block/mirror.c b/block/mirror.c
index 58f391a..25645ef 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -19,6 +19,7 @@
 
 #define SLICE_TIME    100000000ULL /* ns */
 #define MAX_IN_FLIGHT 16
+#define DEFAULT_MIRROR_BUF_SIZE   (10 << 20)
 
 /* The mirroring buffer is a list of granularity-sized chunks.
  * Free chunks are organized in a list.
@@ -671,6 +672,14 @@ static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target,
         return;
     }
 
+    if (buf_size < 0) {
+        error_setg(errp, "Invalid parameter 'buf-size'");
+        return;
+    }
+
+    if (buf_size == 0) {
+        buf_size = DEFAULT_MIRROR_BUF_SIZE;
+    }
 
     s = block_job_create(driver, bs, speed, cb, opaque, errp);
     if (!s) {
@@ -684,7 +693,7 @@ static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target,
     s->is_none_mode = is_none_mode;
     s->base = base;
     s->granularity = granularity;
-    s->buf_size = MAX(buf_size, granularity);
+    s->buf_size = ROUND_UP(buf_size, granularity);
 
     s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp);
     if (!s->dirty_bitmap) {
diff --git a/blockdev.c b/blockdev.c
index 5eaf77e..95a0c6a 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2619,8 +2619,6 @@ out:
     aio_context_release(aio_context);
 }
 
-#define DEFAULT_MIRROR_BUF_SIZE   (10 << 20)
-
 void qmp_drive_mirror(const char *device, const char *target,
                       bool has_format, const char *format,
                       bool has_node_name, const char *node_name,
@@ -2661,7 +2659,7 @@ void qmp_drive_mirror(const char *device, const char *target,
         granularity = 0;
     }
     if (!has_buf_size) {
-        buf_size = DEFAULT_MIRROR_BUF_SIZE;
+        buf_size = 0;
     }
 
     if (granularity != 0 && (granularity < 512 || granularity > 1048576 * 64)) {
-- 
2.1.0