[PULL,2/5] qemu-img: add support for rate limit in qemu-img convert

diff --git a/docs/tools/qemu-img.rst b/docs/tools/qemu-img.rst
index bcb11b0899..b615aa8419 100644
--- a/docs/tools/qemu-img.rst
+++ b/docs/tools/qemu-img.rst
@@ -188,6 +188,10 @@  Parameters to convert subcommand:
   allocated target image depending on the host support for getting allocation
   information.
 
+.. option:: -r
+
+   Rate limit for the convert process
+
 .. option:: --salvage
 
   Try to ignore I/O errors when reading.  Unless in quiet mode (``-q``), errors
@@ -410,7 +414,7 @@  Command description:
   4
     Error on reading data
 
-.. option:: convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [--target-is-zero] [--bitmaps] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-m NUM_COROUTINES] [-W] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME
+.. option:: convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [--target-is-zero] [--bitmaps] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-r RATE_LIMIT] [-m NUM_COROUTINES] [-W] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME
 
   Convert the disk image *FILENAME* or a snapshot *SNAPSHOT_PARAM*
   to disk image *OUTPUT_FILENAME* using format *OUTPUT_FMT*. It can
diff --git a/qemu-img.c b/qemu-img.c
index 3023abea8b..a968c74cba 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -50,6 +50,8 @@ 
 #include "block/qapi.h"
 #include "crypto/init.h"
 #include "trace/control.h"
+#include "qemu/throttle.h"
+#include "block/throttle-groups.h"
 
 #define QEMU_IMG_VERSION "qemu-img version " QEMU_FULL_VERSION \
                           "\n" QEMU_COPYRIGHT "\n"
@@ -1669,6 +1671,7 @@  enum ImgConvertBlockStatus {
 };
 
 #define MAX_COROUTINES 16
+#define CONVERT_THROTTLE_GROUP "img_convert"
 
 typedef struct ImgConvertState {
     BlockBackend **src;
@@ -2184,6 +2187,17 @@  static int convert_copy_bitmaps(BlockDriverState *src, BlockDriverState *dst)
 
 #define MAX_BUF_SECTORS 32768
 
+static void set_rate_limit(BlockBackend *blk, int64_t rate_limit)
+{
+    ThrottleConfig cfg;
+
+    throttle_config_init(&cfg);
+    cfg.buckets[THROTTLE_BPS_WRITE].avg = rate_limit;
+
+    blk_io_limits_enable(blk, CONVERT_THROTTLE_GROUP);
+    blk_set_io_limits(blk, &cfg);
+}
+
 static int img_convert(int argc, char **argv)
 {
     int c, bs_i, flags, src_flags = 0;
@@ -2204,6 +2218,7 @@  static int img_convert(int argc, char **argv)
     bool force_share = false;
     bool explict_min_sparse = false;
     bool bitmaps = false;
+    int64_t rate_limit = 0;
 
     ImgConvertState s = (ImgConvertState) {
         /* Need at least 4k of zeros for sparse detection */
@@ -2226,7 +2241,7 @@  static int img_convert(int argc, char **argv)
             {"bitmaps", no_argument, 0, OPTION_BITMAPS},
             {0, 0, 0, 0}
         };
-        c = getopt_long(argc, argv, ":hf:O:B:Cco:l:S:pt:T:qnm:WU",
+        c = getopt_long(argc, argv, ":hf:O:B:Cco:l:S:pt:T:qnm:WUr:",
                         long_options, NULL);
         if (c == -1) {
             break;
@@ -2323,6 +2338,12 @@  static int img_convert(int argc, char **argv)
         case 'U':
             force_share = true;
             break;
+        case 'r':
+            rate_limit = cvtnum("rate limit", optarg);
+            if (rate_limit < 0) {
+                goto fail_getopt;
+            }
+            break;
         case OPTION_OBJECT: {
             QemuOpts *object_opts;
             object_opts = qemu_opts_parse_noisily(&qemu_object_opts,
@@ -2712,6 +2733,10 @@  static int img_convert(int argc, char **argv)
         s.cluster_sectors = bdi.cluster_size / BDRV_SECTOR_SIZE;
     }
 
+    if (rate_limit) {
+        set_rate_limit(s.target, rate_limit);
+    }
+
     ret = convert_do_copy(&s);
 
     /* Now copy the bitmaps */
diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
index 965c1e3e59..b3620f29e5 100644
--- a/qemu-img-cmds.hx
+++ b/qemu-img-cmds.hx
@@ -46,9 +46,9 @@  SRST
 ERST
 
 DEF("convert", img_convert,
-    "convert [--object objectdef] [--image-opts] [--target-image-opts] [--target-is-zero] [--bitmaps] [-U] [-C] [-c] [-p] [-q] [-n] [-f fmt] [-t cache] [-T src_cache] [-O output_fmt] [-B backing_file] [-o options] [-l snapshot_param] [-S sparse_size] [-m num_coroutines] [-W] [--salvage] filename [filename2 [...]] output_filename")
+    "convert [--object objectdef] [--image-opts] [--target-image-opts] [--target-is-zero] [--bitmaps] [-U] [-C] [-c] [-p] [-q] [-n] [-f fmt] [-t cache] [-T src_cache] [-O output_fmt] [-B backing_file] [-o options] [-l snapshot_param] [-S sparse_size] [-r rate_limit] [-m num_coroutines] [-W] [--salvage] filename [filename2 [...]] output_filename")
 SRST
-.. option:: convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [--target-is-zero] [--bitmaps] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-m NUM_COROUTINES] [-W] [--salvage] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME
+.. option:: convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [--target-is-zero] [--bitmaps] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-r RATE_LIMIT] [-m NUM_COROUTINES] [-W] [--salvage] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME
 ERST
 
 DEF("create", img_create,