backup/datastore: save garbage collection status to disk

and load it again when opening it

this way we can persist the status of the last garbage collect across
daemon reloads and reboots

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>

diff --git a/src/backup/datastore.rs b/src/backup/datastore.rs
index 2389cc6c88af4adad73f7fa0c65ec267e1108a69..485a10ff5be0a31b76c3db29fd9acad859aa45d5 100644 (file)
--- a/src/backup/datastore.rs
+++ b/src/backup/datastore.rs
@@ -9,7 +9,7 @@ use std::fs::File;
 use anyhow::{bail, format_err, Error};
 use lazy_static::lazy_static;
 
-use proxmox::tools::fs::{replace_file, CreateOptions, open_file_locked};
+use proxmox::tools::fs::{replace_file, file_read_optional_string, CreateOptions, open_file_locked};
 
 use super::backup_info::{BackupGroup, BackupDir};
 use super::chunk_store::ChunkStore;
@@ -71,7 +71,20 @@ impl DataStore {
     fn open_with_path(store_name: &str, path: &Path, config: DataStoreConfig) -> Result<Self, Error> {
         let chunk_store = ChunkStore::open(store_name, path)?;
 
-        let gc_status = GarbageCollectionStatus::default();
+        let mut gc_status_path = chunk_store.base_path();
+        gc_status_path.push(".gc-status");
+
+        let gc_status = if let Some(state) = file_read_optional_string(gc_status_path)? {
+            match serde_json::from_str(&state) {
+                Ok(state) => state,
+                Err(err) => {
+                    eprintln!("error reading gc-status: {}", err);
+                    GarbageCollectionStatus::default()
+                }
+            }
+        } else {
+            GarbageCollectionStatus::default()
+        };
 
         Ok(Self {
             chunk_store: Arc::new(chunk_store),
@@ -572,6 +585,23 @@ impl DataStore {
                 crate::task_log!(worker, "Average chunk size: {}", HumanByte::from(avg_chunk));
             }
 
+            if let Ok(serialized) = serde_json::to_string(&gc_status) {
+                let mut path = self.base_path();
+                path.push(".gc-status");
+
+                let backup_user = crate::backup::backup_user()?;
+                let mode = nix::sys::stat::Mode::from_bits_truncate(0o0644);
+                // set the correct owner/group/permissions while saving file
+                // owner(rw) = backup, group(r)= backup
+                let options = CreateOptions::new()
+                    .perm(mode)
+                    .owner(backup_user.uid)
+                    .group(backup_user.gid);
+
+                // ignore errors
+                let _ = replace_file(path, serialized.as_bytes(), options);
+            }
+
             *self.last_gc_status.lock().unwrap() = gc_status;
 
         } else {