[pve-devel] [PATCH storage] plugin: file size info: use fallback for actual size

[Fiona Ebner <f.ebner@proxmox.com>]

The actual-size property is an optional property in the QAPI
definition for ImageInfo. If it's not set, simply use the information
from stat() as a fallback. This is essentially the same
raw_get_allocated_file_size() in QEMU does anyways.

Reported in the community forum:
https://forum.proxmox.com/threads/118443/post-513421

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---

Thanks to Mira for setting up a GlusterFS instance and discussing the
issue with me!

I'm not sure why QEMU fails here, didn't see much that could go wrong
beside the fstat() call failing. But our stat() call in the beginning
of file_size_info already succeeded at that point :/ The mysteries of
QEMU+GlusterFS.

Also, it's a bit strange to call qemu-img info regardless of whether
the image is a VM image or not. E.g., this results in the format
property for backups to always be raw, rather than the backup format.
Should we change that (for 8.0)?

 PVE/Storage/Plugin.pm | 1 +
 1 file changed, 1 insertion(+)

diff --git a/PVE/Storage/Plugin.pm b/PVE/Storage/Plugin.pm
index 8a41df1..7773ac3 100644
--- a/PVE/Storage/Plugin.pm
+++ b/PVE/Storage/Plugin.pm
@@ -899,6 +899,7 @@ sub file_size_info {
     }
 
     my ($size, $format, $used, $parent) = $info->@{qw(virtual-size format actual-size backing-filename)};
+    $used ||= $st->blocks * 512;
 
     ($size) = ($size =~ /^(\d+)$/) or die "size '$size' not an integer\n"; # untaint
     # coerce back from string
-- 
2.30.2