[PATCH manager 1/2] fix #7860: api: pool: do not delete when used by backup job

[Elias Huhsovitz <e.huhsovitz@proxmox.com>]

Currently, deleting a pool that is used by a backup is allowed. This
results in a suboptimal configuration where calling the API endpoint
`/cluster/backup-info/not-backed-up` fails, because it tries to query
the VMs from the non-existent pool.

Mitigate this issue by not allowing pools used by backups to be deleted.

Signed-off-by: Elias Huhsovitz <e.huhsovitz@proxmox.com>
---
 PVE/API2/Pool.pm | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/PVE/API2/Pool.pm b/PVE/API2/Pool.pm
index 63aff5bb..a0ff8a31 100644
--- a/PVE/API2/Pool.pm
+++ b/PVE/API2/Pool.pm
@@ -475,6 +475,19 @@ __PACKAGE__->register_method({
     },
 });
 
+my sub check_pool_used_in_backup_job {
+    my ($pool) = @_;
+
+    my $backup_jobs = cfs_read_file('jobs.cfg');
+
+    for my $job_id (keys $backup_jobs->{ids}->%*) {
+        my $referenced_pool = $backup_jobs->{ids}->{$job_id}->{pool};
+        next if !defined($referenced_pool);
+        next if $referenced_pool ne $pool;
+        die "pool '$pool' is used in backup job '$job_id'\n";
+    }
+}
+
 __PACKAGE__->register_method({
     name => 'delete_pool',
     protected => 1,
@@ -524,6 +537,8 @@ __PACKAGE__->register_method({
                     die "pool '$pool' is not empty (contains storage '$storeid')\n";
                 }
 
+                check_pool_used_in_backup_job($pool);
+
                 delete($usercfg->{pools}->{$pool});
                 PVE::AccessControl::delete_pool_acl($pool, $usercfg);
 
-- 
2.47.3