Re: [Qemu-devel] [PATCH V7 4/6] qemu-img: add -l for snapshot in convert

[Wenchao Xia]

于 2013/12/5 4:42, Eric Blake 写道:

On 12/04/2013 02:10 AM, Wenchao Xia wrote:

Now qemu-img convert have similar options as qemu-nbd for internal
snapshot.

Signed-off-by: Wenchao Xia <xiaw...@linux.vnet.ibm.com>
---

@@ -1183,6 +1189,18 @@ static int img_convert(int argc, char **argv)
          case 's':
              snapshot_name = optarg;
              break;
+        case 'l':
+            if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
+                sn_opts = qemu_opts_parse(&internal_snapshot_opts, optarg, 0);
+                if (!sn_opts) {
+                    error_report("Failed in parsing snapshot param '%s'",
+                                 optarg);
+                    return 1;
+                }
+            } else {
+                snapshot_name = optarg;
+            }
+            break;

Do we want a followup patch that makes it an error to use -l and -s
together?  Without such a patch, we have the odd behavior that:

convert -l name1 -s name2

loads name2, but:

convert -l snapshot.name=name1 -s name2

loads name1.  Confusing that the choice of HOW the argument to -l is
specified determines whether the -s has any impact.

For that matter, why can't '-s' and '-l' be made synonyms of each other?
  In other words, why not support:

convert -s snapshot.name=name1

  Previous I planned to use -l for internal snapshot in all possible
program, since -s is taken as external snapshot in qemu, qemu-nbd.
let -s stands for internal in qemu-img convert only, may bring
confuse to user, so I deprecated it instead of enhance it(I want
to remove it but may bring compatiablity issue).
  Yes, it should report error when both specified, will send a patch
if you agree '-l' should still be used.