[4/4] qemu-img: Enable progress output for commit

diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
index d029609..8bc55cd 100644
--- a/qemu-img-cmds.hx
+++ b/qemu-img-cmds.hx
@@ -22,9 +22,9 @@  STEXI
 ETEXI
 
 DEF("commit", img_commit,
-    "commit [-q] [-f fmt] [-t cache] filename")
+    "commit [-q] [-f fmt] [-t cache] [-p] filename")
 STEXI
-@item commit [-q] [-f @var{fmt}] [-t @var{cache}] @var{filename}
+@item commit [-q] [-f @var{fmt}] [-t @var{cache}] [-p] @var{filename}
 ETEXI
 
 DEF("compare", img_compare,
diff --git a/qemu-img.c b/qemu-img.c
index 22ce01d..84119df 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -690,12 +690,27 @@  static void dummy_block_job_cb(void *opaque, int ret)
 static void run_block_job(BlockJob *job, Error **errp)
 {
     BlockJobInfo *info;
+    uint64_t mod_offset = 0;
 
     do {
         aio_poll(qemu_get_aio_context(), true);
 
         info = block_job_query(job);
 
+        if (info->offset) {
+            if (!mod_offset) {
+                /* Some block jobs (at least "commit") will only work on a
+                 * subset of the image file and therefore basically skip many
+                 * sectors at the start (processing them apparently
+                 * instantaneously). These sectors should be ignored when
+                 * calculating the progress. */
+                mod_offset = info->offset;
+            }
+
+            qemu_progress_print((float)(info->offset - mod_offset) /
+                                (info->len - mod_offset) * 100.f, 0);
+        }
+
         if (!info->busy && info->offset < info->len) {
             block_job_resume(job);
         }
@@ -712,13 +727,13 @@  static int img_commit(int argc, char **argv)
     int c, ret, flags;
     const char *filename, *fmt, *cache;
     BlockDriverState *bs, *base_bs;
-    bool quiet = false;
+    bool progress = false, quiet = false;
     Error *local_err = NULL;
 
     fmt = NULL;
     cache = BDRV_DEFAULT_CACHE;
     for(;;) {
-        c = getopt(argc, argv, "f:ht:q");
+        c = getopt(argc, argv, "f:ht:qp");
         if (c == -1) {
             break;
         }
@@ -733,12 +748,20 @@  static int img_commit(int argc, char **argv)
         case 't':
             cache = optarg;
             break;
+        case 'p':
+            progress = true;
+            break;
         case 'q':
             quiet = true;
             break;
         }
     }
 
+    /* Progress is not shown in Quiet mode */
+    if (quiet) {
+        progress = false;
+    }
+
     if (optind != argc - 1) {
         help();
     }
@@ -756,6 +779,9 @@  static int img_commit(int argc, char **argv)
         return 1;
     }
 
+    qemu_progress_init(progress, 1.f);
+    qemu_progress_print(0.f, 100);
+
     base_bs = bdrv_find_base(bs);
     if (!base_bs) {
         error_set(&local_err, QERR_BASE_NOT_FOUND, "NULL");
@@ -772,6 +798,8 @@  static int img_commit(int argc, char **argv)
     run_block_job(bs->job, &local_err);
 
 done:
+    qemu_progress_end();
+
     bdrv_unref(bs);
 
     if (error_is_set(&local_err)) {
diff --git a/qemu-img.texi b/qemu-img.texi
index f84590e..1a9c08f 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -140,7 +140,7 @@  this case. @var{backing_file} will never be modified unless you use the
 The size can also be specified using the @var{size} option with @code{-o},
 it doesn't need to be specified separately in this case.
 
-@item commit [-f @var{fmt}] [-t @var{cache}] @var{filename}
+@item commit [-q] [-f @var{fmt}] [-t @var{cache}] [-p] @var{filename}
 
 Commit the changes recorded in @var{filename} in its base image or backing file.
 If the backing file is smaller than the snapshot, then the backing file will be