[pve-devel] [PATCH proxmox-offline-mirror 2/2] medium: remove snapshot link directories not present in source mirror

[Stoiko Ivanov]

Currently a medium sync takes care to remove all files and the links
in the individual snapshot directories, but leaves the empty snapshot
hierarchy in place. This causes a medium sync to take longer than
necessary, as we walk through the complete mirror on the medium,
including all empty link directories.

The status output is misleading as well, still showing more snapshots
than actually present (in the sense of containing any files).

Noticed on a system, which creates snapshots on a daily basis, after a
cleanup removing many snapshots and running garbage collection on the
mirror and the medium, still caused the medium sync to be quite slow.

Signed-off-by: Stoiko Ivanov <s.ivanov at proxmox.com>
---
 src/medium.rs | 18 +++++++++++++++++-
 src/types.rs  |  2 +-
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/medium.rs b/src/medium.rs
index 53df50d..2c2d24e 100644
--- a/src/medium.rs
+++ b/src/medium.rs
@@ -15,7 +15,7 @@ use serde::{Deserialize, Serialize};
 
 use crate::{
     config::{self, ConfigLockGuard, MediaConfig, MirrorConfig},
-    generate_repo_file_line,
+    generate_repo_file_line, mirror,
     mirror::pool,
     pool::Pool,
     types::{Diff, Snapshot, SNAPSHOT_REGEX},
@@ -404,6 +404,22 @@ pub fn sync(
             Pool::create(&mirror_base, &mirror_pool)?
         };
 
+        let source_snapshots: HashSet<Snapshot> =
+            mirror::list_snapshots(&mirror)?.iter().cloned().collect();
+        let target_snapshots: HashSet<Snapshot> = list_snapshots(medium_base, &mirror.id)?
+            .iter()
+            .cloned()
+            .collect();
+        let target_only_snapshots = target_snapshots.difference(&source_snapshots);
+        for snapshot in target_only_snapshots.into_iter() {
+            let path = target_pool.get_path(Path::new(&snapshot.to_string()))?;
+            println!(
+                "Removing snapshot no longer present on mirror: {:?}",
+                &snapshot.to_string()
+            );
+            target_pool.lock()?.remove_dir(&path)?;
+        }
+
         let source_pool: Pool = pool(&mirror)?;
         source_pool.lock()?.sync_pool(&target_pool, medium.verify)?;
 
diff --git a/src/types.rs b/src/types.rs
index 7544d5e..94eee79 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -71,7 +71,7 @@ const_regex! {
     type: String,
     format: &ApiStringFormat::Pattern(&SNAPSHOT_REGEX),
 )]
-#[derive(Debug, Clone, Copy, PartialEq, PartialOrd, Eq, Ord)]
+#[derive(Debug, Clone, Copy, PartialEq, PartialOrd, Eq, Ord, Hash)]
 /// Mirror snapshot
 pub struct Snapshot(i64);
 
-- 
2.39.2