[pve-devel] [PATCH v4 storage 1/9] storage: add new find_free_volname

[Aaron Lauterer <a.lauterer@proxmox.com>]

This new method exposes the functionality to request a new, not yet
used, volname for a storage.

The default implementation will return the result from
'find_free_diskname' prefixed with "<VMID>/" if $scfg->{path} exists.
Otherwise it will only return the result from 'find_free_diskname'.

If the format suffix is added also depends on the existence of
$scfg->{path}.

$scfg->{path} will be present for directory based storage types.

Should a storage need to return different volname, it needs to override
the 'find_free_volname' method.

Signed-off-by: Aaron Lauterer <a.lauterer@proxmox.com>
---

v3 -> v4:
* fix style nit

v2 -> v3:
* dropped exists() check
* fixed base image handling
* fixed smaller code style issues

v1 -> v2:
* many small fixes and improvements
* rename_volume now accepts $source_volname instead of $source_volid
    helps us to avoid to parse the volid a second time

rfc -> v1:
* reduced number of parameters to minimum needed, plugins infer needed
  information themselves
* added storage locking and checking if volume already exists
* parse target_volname prior to renaming to check if valid

old dedicated API endpoint -> rfc:
only do rename now but the rename function handles templates and returns
the new volid as this can be differently handled on some storages.
 
 PVE/Storage.pm        | 9 +++++++++
 PVE/Storage/Plugin.pm | 8 ++++++++
 2 files changed, 17 insertions(+)

diff --git a/PVE/Storage.pm b/PVE/Storage.pm
index 71d6ad7..4fbeaea 100755
--- a/PVE/Storage.pm
+++ b/PVE/Storage.pm
@@ -203,6 +203,15 @@ sub storage_can_replicate {
     return $plugin->storage_can_replicate($scfg, $storeid, $format);
 }
 
+sub find_free_volname {
+    my ($cfg, $storeid, $vmid, $fmt) = @_;
+
+    my $scfg = storage_config($cfg, $storeid);
+    my $plugin = PVE::Storage::Plugin->lookup($scfg->{type});
+
+    return $plugin->find_free_volname($storeid, $scfg, $vmid, $fmt);
+}
+
 sub storage_ids {
     my ($cfg) = @_;
 
diff --git a/PVE/Storage/Plugin.pm b/PVE/Storage/Plugin.pm
index aeb4fff..d21c874 100644
--- a/PVE/Storage/Plugin.pm
+++ b/PVE/Storage/Plugin.pm
@@ -732,6 +732,14 @@ sub find_free_diskname {
     return get_next_vm_diskname($disk_list, $storeid, $vmid, $fmt, $scfg, $add_fmt_suffix);
 }
 
+sub find_free_volname {
+    my ($class, $storeid, $scfg, $vmid, $fmt) = @_;
+
+    my $diskname = $class->find_free_diskname($storeid, $scfg, $vmid, $fmt, $scfg->{path});
+
+    return $scfg->{path} ? "${vmid}/$diskname" : $diskname;
+}
+
 sub clone_image {
     my ($class, $scfg, $storeid, $volname, $vmid, $snap) = @_;
 
-- 
2.30.2