From: Chen Hanxiao <chenhanxiao@gmail.com>

If we set mountpoints to qmp_guest_fsfreeze_freeze_list,
we may got nothing to freeze as all mountpoints are
not valid.
Call ga_unset_frozen in this senario.

Cc: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Chen Hanxiao <chenhanxiao@gmail.com>
---
Rebase on master

 qga/commands-posix.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index e809e382eb..9fd51f1d7a 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -1273,6 +1273,12 @@ int64_t qmp_guest_fsfreeze_freeze_list(bool has_mountpoints,
     }
 
     free_fs_mount_list(&mounts);
+    /* We may not issue any FIFREEZE here when had mountpoints.
+     * Just unset ga_state here and ready for the next call.
+     */
+    if (has_mountpoints && i == 0) {
+        ga_unset_frozen(ga_state);
+    }
     return i;
 
 error:
-- 
2.14.3

Quoting Chen Hanxiao (2018-02-08 19:35:42)
> From: Chen Hanxiao <chenhanxiao@gmail.com>
> 
> If we set mountpoints to qmp_guest_fsfreeze_freeze_list,
> we may got nothing to freeze as all mountpoints are
> not valid.
> Call ga_unset_frozen in this senario.
> 
> Cc: Michael Roth <mdroth@linux.vnet.ibm.com>
> Signed-off-by: Chen Hanxiao <chenhanxiao@gmail.com>
> ---
> Rebase on master
> 
>  qga/commands-posix.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/qga/commands-posix.c b/qga/commands-posix.c
> index e809e382eb..9fd51f1d7a 100644
> --- a/qga/commands-posix.c
> +++ b/qga/commands-posix.c
> @@ -1273,6 +1273,12 @@ int64_t qmp_guest_fsfreeze_freeze_list(bool has_mountpoints,
>      }
> 
>      free_fs_mount_list(&mounts);
> +    /* We may not issue any FIFREEZE here when had mountpoints.
> +     * Just unset ga_state here and ready for the next call.
> +     */
> +    if (has_mountpoints && i == 0) {
> +        ga_unset_frozen(ga_state);
> +    }

It seems odd to special-case has_mountpoints. Wouldn't:

  if (i == 0) {
    ...
  }

be more consistent? Then management could infer i==0 leaves qga in
unfrozen state. Otherwise I'd rather just stick with expecting a
gratuitous unfreeze() since it requires less special-casing on the
management/ side.

And if we do change this, we'd probably want to update
qga/qapi-schema.json to reflect the behavior. I.e.:

##
# @guest-fsfreeze-freeze:
#
# Sync and freeze all freezable, local guest filesystems. If this
# command succeeded, you may call @guest-fsfreeze-thaw later to
# unfreeze.
...
# Returns: Number of file systems currently frozen. On error, all filesystems
-# will be thawed.
+# will be thawed. If no filesystems are frozen as a result of this call,
+# then @guest-fsfreeze-status will remain "thawed" and calling
+# @guest-fsfreeze-thaw is not necessary.


>      return i;
> 
>  error:
> -- 
> 2.14.3
> 

At 2018-02-16 02:41:25, "Michael Roth" <mdroth@linux.vnet.ibm.com> wrote:
>Quoting Chen Hanxiao (2018-02-08 19:35:42)
>> From: Chen Hanxiao <chenhanxiao@gmail.com>
>> 
>> If we set mountpoints to qmp_guest_fsfreeze_freeze_list,
>> we may got nothing to freeze as all mountpoints are
>> not valid.
>> Call ga_unset_frozen in this senario.
>> 
>> Cc: Michael Roth <mdroth@linux.vnet.ibm.com>
>> Signed-off-by: Chen Hanxiao <chenhanxiao@gmail.com>
>> ---
>> Rebase on master
>> 
>>  qga/commands-posix.c | 6 ++++++
>>  1 file changed, 6 insertions(+)
>> 
>> diff --git a/qga/commands-posix.c b/qga/commands-posix.c
>> index e809e382eb..9fd51f1d7a 100644
>> --- a/qga/commands-posix.c
>> +++ b/qga/commands-posix.c
>> @@ -1273,6 +1273,12 @@ int64_t qmp_guest_fsfreeze_freeze_list(bool has_mountpoints,
>>      }
>> 
>>      free_fs_mount_list(&mounts);
>> +    /* We may not issue any FIFREEZE here when had mountpoints.
>> +     * Just unset ga_state here and ready for the next call.
>> +     */
>> +    if (has_mountpoints && i == 0) {
>> +        ga_unset_frozen(ga_state);
>> +    }
>
>It seems odd to special-case has_mountpoints. Wouldn't:
>
>  if (i == 0) {
>    ...
>  }
>
>be more consistent? Then management could infer i==0 leaves qga in
>unfrozen state. Otherwise I'd rather just stick with expecting a
>gratuitous unfreeze() since it requires less special-casing on the
>management/ side.
>
>And if we do change this, we'd probably want to update
>qga/qapi-schema.json to reflect the behavior. I.e.:
>
>##
># @guest-fsfreeze-freeze:
>#
># Sync and freeze all freezable, local guest filesystems. If this
># command succeeded, you may call @guest-fsfreeze-thaw later to
># unfreeze.
>...
># Returns: Number of file systems currently frozen. On error, all filesystems
>-# will be thawed.
>+# will be thawed. If no filesystems are frozen as a result of this call,
>+# then @guest-fsfreeze-status will remain "thawed" and calling
>+# @guest-fsfreeze-thaw is not necessary.
>

Thanks for the review.
Will be fixed in v2.

Regards,
- Chen