On March 26, 2025 3:20 pm, Max Carrara wrote:
> Add documentation for the following methods:
> - list_images
> - create_base
> - clone_image
> - alloc_image
> - free_image
>
> Signed-off-by: Max Carrara <m.carr...@proxmox.com>
> Co-authored-by: Maximiliano Sandoval <m.sando...@proxmox.com>
> ---
> src/PVE/Storage/PluginBase.pm | 111 ++++++++++++++++++++++++++++++++++
> 1 file changed, 111 insertions(+)
>
> diff --git a/src/PVE/Storage/PluginBase.pm b/src/PVE/Storage/PluginBase.pm
> index b3ce684..37b1471 100644
> --- a/src/PVE/Storage/PluginBase.pm
> +++ b/src/PVE/Storage/PluginBase.pm
> @@ -721,26 +721,137 @@ sub on_delete_hook {
>
> =cut
>
> +=head3 $plugin->list_images($storeid, \%scfg [, $vmid, \@vollist, \%cache])
> +
> +B<REQUIRED:> Must be implemented in every storage plugin.
> +
> +Returns a listref of all disk images of a storage. If the storage does not
> +support storing disk images, returns an empty listref.
> +
> +Optionally, if C<\@vollist> is provided, return only disks whose volume ID is
> +within C<\@vollist>. Note that this usually has higher precedence than
> +C<$vmid>.
what does usually mean? what does $vmid do?
> +
> +C<die>s in case of errors.
> +
> +This method may reuse L<< cached information via C<\%cache>|/"CACHING
> EXPENSIVE OPERATIONS" >>.
> +
> +The returned listref has the following structure:
> +
> + [
> + {
> + ctime => "1689163322", # creation time as unix timestamp
> + format => "raw",
> + size => 8589934592, # in bytes!
> + vmid => 101,
> + volid => "local-lvm:base-101-disk-0", # volume ID, storage-specific
> + },
> + # [...]
> + ]
> +
> +=cut
> +
> sub list_images {
> my ($class, $storeid, $scfg, $vmid, $vollist, $cache) = @_;
> croak "implement me in sub-class\n";
> }
>
> +=head3 $plugin->create_base($storeid, \%scfg, $volname)
> +
> +B<OPTIONAL:> May be implemented in a storage plugin.
> +
> +Creates a base volume from an existing volume, allowing the volume to be
this is misleading - it doesn't create a base volume from an existing
volume, it *converts* an existing volume into a base volume!
> +L<< cloned|/"$plugin->clone_image(...)" >>. This cloned volume (usually
> +a disk image) may then be used as a base for the purpose of creating linked
this is wrong? there is no cloned volume yet? and all of this only
applies to images and not other volumes?
> +clones. See L<C<PVE::Storage::LvmThinPlugin>> and
> +L<C<PVE::Storage::ZFSPoolPlugin>> for example implementations.
> +
> +On completion, returns the name of the new base volume (the new C<$volname>).
> +
> +This method is called in the context of C<L<<
> cluster_lock_storage()|/"cluster_lock_storage(...)" >>>,
> +i.e. when the storage is B<locked>.
Shouldn't this say that it *should* be called in a locked context?
> +
> +=cut
> +
> sub create_base {
> my ($class, $storeid, $scfg, $volname) = @_;
> croak "implement me in sub-class\n";
> }
>
> +=head3 $plugin->clone_image($scfg, $storeid, $volname, $vmid [, $snap])
> +
> +=head3 $plugin->clone_image(...)
> +
> +B<REQUIRED:> Must be implemented in every storage plugin.
not really? there's a feature guard for it, so only storage plugins that
support it should ever get it called anyway..
what does $vmid mean?
> +
> +Clones a disk image or a snapshot of an image, returning the name of the new
> +image (the new C<$volname>). Note that I<cloning> here means to create a
> linked
> +clone and not duplicating an image. See L<C<PVE::Storage::LvmThinPlugin>> and
> +L<C<PVE::Storage::ZFSPoolPlugin>> for example implementations.
then why not start with
"Creates a linked clone of an existing disk image or snapshot of an
image"
? maybe also include that unless the linked clone is 100% independent
from the base (only true for LVM thin atm?), the new volid should encode
the base->clone relation in the volname?
> +
> +C<die>s in case of an error of if the underlying storage doesn't support
s/of/or/
> +cloning images.
> +
> +This method is called in the context of C<L<<
> cluster_lock_storage()|/"cluster_lock_storage(...)" >>>,
> +i.e. when the storage is B<locked>.
same as above
> +
> +=cut
> +
> sub clone_image {
> my ($class, $scfg, $storeid, $volname, $vmid, $snap) = @_;
> croak "implement me in sub-class\n";
> }
>
> +=head3 $plugin->alloc_image($storeid, $scfg, $vmid, $fmt, $name, $size)
> +
> +B<REQUIRED:> Must be implemented in every storage plugin.
> +
> +Allocates a disk image with the given format C<$fmt> and C<$size> in bytes,
> +returning the name of the new image (the new C<$volname>). See
> +C<L<< plugindata()|/"$plugin->plugindata()" >>> for all disk formats.
> +
> +Optionally, if given, set the name of the image to C<$name>. If C<$name>
> isn't
> +provided, the next name should be determined via C<L<<
> find_free_diskname()|/"$plugin->find_free_diskname(...)" >>>.
a suitable name should be automatically generated, unless we really want
to stabilize find_free_diskname as part of the API..
what does $vmid mean?
> +
> +C<die>s in case of an error of if the underlying storage doesn't support
> +allocating images.
> +
> +This method is called in the context of C<L<<
> cluster_lock_storage()|/"cluster_lock_storage(...)" >>>,
> +i.e. when the storage is B<locked>.
> +
> +=cut
> +
> sub alloc_image {
> my ($class, $storeid, $scfg, $vmid, $fmt, $name, $size) = @_;
> croak "implement me in sub-class\n";
> }
>
> +=head3 $plugin->free_image($storeid, $scfg, $volname [, $isBase, $format])
> +
> +=head3 $plugin->free_image(...)
> +
> +B<REQUIRED:> Must be implemented in every storage plugin.
> +
> +Frees (deletes) the disk image given by C<$volname>. Optionally, the image
> may
> +be a base image (C<$isBase>) and have a certain C<$format>. See
> +C<L<< plugindata()|/"$plugin->plugindata()" >>> for all disk formats.
> +
> +If a cleanup is required after freeing the image, returns a reference to a
> +subroutine that performs the cleanup, and C<undef> otherwise.
might be a good idea to explain why? also, what do $isBase and $format
mean?
> +
> +C<die>s in case of errors, if the image has a L<< C<protected>
> attribute|/"$plugin->get_volume_attribute(...)" >>
> +(and may thus not be freed), or if the underlying storage implementation
> +doesn't support freeing images.
> +
> +This method is called in the context of C<L<<
> cluster_lock_storage()|/"cluster_lock_storage(...)" >>>,
> +i.e. when the storage is B<locked>.
> +
> +B<NOTE:> The returned cleanup subroutine is called in a separate worker and
> +should L<< lock|/"$plugin->cluster_lock_storage(...)" >> the underlying
> storage
> +separately.
it should? or it must?
> +
> +=cut
> +
> sub free_image {
> my ($class, $storeid, $scfg, $volname, $isBase, $format) = @_;
> croak "implement me in sub-class\n";
> --
> 2.39.5
>
>
>
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