commit bd39e6ed0b88a1473c652c97e731a156cccf16e2
author Max Reitz <mreitz@redhat.com> Tue Jul 22 22:58:43 2014 +0200
committer Kevin Wolf <kwolf@redhat.com> Fri Aug 22 14:54:48 2014 +0200
tree 68cd59ae096c360b62b9f55a6062979fb15ac7de
parent 40055951a7afbfc037c6c7351d72a5c5d83ed99b

qemu-img: Allow cache mode specification for amend

qemu-img amend may extensively modify the target image, depending on the
options to be amended (e.g. conversion to qcow2 compat level 0.10 from
1.1 for an image with many unallocated zero clusters). Therefore it
makes sense to allow the user to specify the cache mode to be used.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

qemu-img-cmds.hx

diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
index 48df0b8..55aec6b 100644
--- a/qemu-img-cmds.hx
+++ b/qemu-img-cmds.hx
@@ -70,8 +70,8 @@
 ETEXI
 
 DEF("amend", img_amend,
-    "amend [-q] [-f fmt] -o options filename")
+    "amend [-q] [-f fmt] [-t cache] -o options filename")
 STEXI
-@item amend [-q] [-f @var{fmt}] -o @var{options} @var{filename}
+@item amend [-q] [-f @var{fmt}] [-t @var{cache}] -o @var{options} @var{filename}
 @end table
 ETEXI

qemu-img.c

diff --git a/qemu-img.c b/qemu-img.c
index df85405..c843420 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -2778,12 +2778,14 @@
     char *options = NULL;
     QemuOptsList *create_opts = NULL;
     QemuOpts *opts = NULL;
-    const char *fmt = NULL, *filename;
+    const char *fmt = NULL, *filename, *cache;
+    int flags;
     bool quiet = false;
     BlockDriverState *bs = NULL;
 
+    cache = BDRV_DEFAULT_CACHE;
     for (;;) {
-        c = getopt(argc, argv, "hqf:o:");
+        c = getopt(argc, argv, "ho:f:t:q");
         if (c == -1) {
             break;
         }
@@ -2810,6 +2812,9 @@
             case 'f':
                 fmt = optarg;
                 break;
+            case 't':
+                cache = optarg;
+                break;
             case 'q':
                 quiet = true;
                 break;
@@ -2832,8 +2837,14 @@
         error_exit("Expecting one image file name");
     }
 
-    bs = bdrv_new_open("image", filename, fmt,
-                       BDRV_O_FLAGS | BDRV_O_RDWR, true, quiet);
+    flags = BDRV_O_FLAGS | BDRV_O_RDWR;
+    ret = bdrv_parse_cache_flags(cache, &flags);
+    if (ret < 0) {
+        error_report("Invalid cache option: %s", cache);
+        goto out;
+    }
+
+    bs = bdrv_new_open("image", filename, fmt, flags, true, quiet);
     if (!bs) {
         error_report("Could not open image '%s'", filename);
         ret = -1;

qemu-img.texi

diff --git a/qemu-img.texi b/qemu-img.texi
index 688b28d..cb68948 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -397,7 +397,7 @@
 partitioning tools inside the VM to actually begin using the new space on the
 device.
 
-@item amend [-f @var{fmt}] -o @var{options} @var{filename}
+@item amend [-f @var{fmt}] [-t @var{cache}] -o @var{options} @var{filename}
 
 Amends the image format specific @var{options} for the image file
 @var{filename}. Not all file formats support this operation.