[pbs-devel] [RFC v2 proxmox-backup 14/21] datastore: GC: clean-up trashed snapshots, groups and namespaces

[Christian Ebner]

Cleanup trashed items during phase 1 of garbage collection. If
encountered, index files located within trashed snapshots are touched
as well, deferring chunk cleanup to the next run

Signed-off-by: Christian Ebner <c.ebner at proxmox.com>
---
 pbs-datastore/src/datastore.rs | 84 +++++++++++++++++++++++++++++++++-
 1 file changed, 83 insertions(+), 1 deletion(-)

diff --git a/pbs-datastore/src/datastore.rs b/pbs-datastore/src/datastore.rs
index ca05e1bea..d88af4c68 100644
--- a/pbs-datastore/src/datastore.rs
+++ b/pbs-datastore/src/datastore.rs
@@ -574,6 +574,18 @@ impl DataStore {
         !path.exists()
     }
 
+    /// Checks if the namespace trash marker file exists,
+    /// does not imply that the namespace itself exists.
+    pub fn namespace_is_trashed(&self, namespace: &BackupNamespace) -> bool {
+        if namespace.is_root() {
+            return false;
+        }
+        let mut path = self.base_path();
+        path.push(namespace.path());
+        path.push(TRASH_MARKER_FILENAME);
+        path.exists()
+    }
+
     /// Remove the namespace and all it's parent components from the trash by removing the trash or
     /// trash-pending marker file for each namespace level from deepest to shallowest. Missing files
     /// are ignored.
@@ -1322,7 +1334,7 @@ impl DataStore {
             .context("creating namespace iterator failed")?
         {
             let namespace = namespace.context("iterating namespaces failed")?;
-            for group in arc_self.iter_backup_groups(namespace)? {
+            for group in arc_self.iter_backup_groups(namespace.clone())? {
                 let group = group.context("iterating backup groups failed")?;
 
                 // Avoid race between listing/marking of snapshots by GC and pruning the last
@@ -1403,10 +1415,80 @@ impl DataStore {
                             }
                             processed_index_files += 1;
                         }
+
+                        // Only try to lock a trashed snapshots and continue if that is not
+                        // possible, as then most likely this is in the process of being untrashed.
+                        // Check trash state before and after locking to avoid otherwise possible
+                        // races.
+                        if snapshot.backup_dir.is_trashed() {
+                            if let Ok(_lock) = snapshot.backup_dir.lock() {
+                                if snapshot.backup_dir.is_trashed() {
+                                    let path = snapshot.backup_dir.full_path();
+                                    log::info!("removing trashed backup snapshot {path:?}");
+                                    std::fs::remove_dir_all(&path).with_context(|| {
+                                        format!("removing trashed backup snapshot {path:?} failed")
+                                    })?;
+                                }
+                            } else {
+                                let path = snapshot.backup_dir.full_path();
+                                warn!("failed to lock trashed backup snapshot can {path:?}");
+                            }
+                        }
                     }
 
                     break;
                 }
+                if group.is_trashed() {
+                    if let Ok(_lock) = group.lock() {
+                        if group.is_trashed() {
+                            let trash_path = group.full_group_path().join(".trashed");
+                            std::fs::remove_file(&trash_path).map_err(|err| {
+                                format_err!(
+                                    "removing the trash file '{trash_path:?}' failed - {err}"
+                                )
+                            })?;
+
+                            let owner_path = group.full_group_path().join("owner");
+                            std::fs::remove_file(&owner_path).map_err(|err| {
+                                format_err!(
+                                    "removing the owner file '{owner_path:?}' failed - {err}"
+                                )
+                            })?;
+
+                            let path = group.full_group_path();
+
+                            std::fs::remove_dir(&path).map_err(|err| {
+                                format_err!("removing group directory {path:?} failed - {err}")
+                            })?;
+
+                            // Remove any now empty backup type directory
+                            let base_file = std::fs::File::open(self.base_path())?;
+                            let base_fd = base_file.as_raw_fd();
+                            for ty in BackupType::iter() {
+                                let mut ty_dir = namespace.path();
+                                ty_dir.push(ty.to_string());
+                                match unlinkat(Some(base_fd), &ty_dir, UnlinkatFlags::RemoveDir) {
+                                    Ok(_) => (),
+                                    Err(nix::errno::Errno::ENOENT) |
+                                    Err(nix::errno::Errno::ENOTEMPTY) => (),
+                                    Err(err) => info!("failed to remove backup type directory for {namespace} - {err}"),
+                                }
+                            }
+                        } else {
+                            let path = group.full_group_path();
+                            warn!("failed to lock trashed backup group {path:?}");
+                        }
+                    }
+                }
+            }
+            if self.namespace_is_trashed(&namespace) {
+                // Remove the namespace, but only if it was empty (as the GC already cleared child
+                // items and no new ones have been created since).
+                match arc_self.destroy_namespace_recursive(&namespace, false) {
+                    Ok(true) => info!("removed trashed namespace {namespace}"),
+                    Ok(false) => info!("failed to remove trashed namespace {namespace}, not empty"),
+                    Err(err) => warn!("removing trashed namespace failed: {err:#}"),
+                }
             }
         }
 
-- 
2.39.5