proxmox-backup-proxy: fix leftover references on datastore removal

when we remove a datastore via api/cli, the proxy
has sometimes leftover references to that datastore in its
DATASTORE_MAP which includes an open filehandle on the
'.lock' file

this prevents unmounting/exporting the datastore even after removal,
only a reload/restart of the proxy did help

add a command to our command socket, which removes all non
configured datastores from the map, dropping the open filehandle

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

src/api2/config/datastore.rs

@@ -403,7 +403,7 @@ pub fn update_datastore(
     },
 )]
 /// Remove a datastore configuration.
-pub fn delete_datastore(name: String, digest: Option<String>) -> Result<(), Error> {
+pub async fn delete_datastore(name: String, digest: Option<String>) -> Result<(), Error> {
 
     let _lock = open_file_locked(datastore::DATASTORE_CFG_LOCKFILE, std::time::Duration::new(10, 0), true)?;
 
@@ -425,6 +425,8 @@ pub fn delete_datastore(name: String, digest: Option<String>) -> Result<(), Erro
     let _ = jobstate::remove_state_file("prune", &name);
     let _ = jobstate::remove_state_file("garbage_collection", &name);
 
+    crate::server::notify_datastore_removed().await?;
+
     Ok(())
 }
 

src/backup/datastore.rs

@@ -69,6 +69,18 @@ impl DataStore {
         Ok(datastore)
     }
 
+    /// removes all datastores that are not configured anymore
+    pub fn remove_unused_datastores() -> Result<(), Error>{
+        let (config, _digest) = datastore::config()?;
+
+        let mut map = DATASTORE_MAP.lock().unwrap();
+        // removes all elements that are not in the config
+        map.retain(|key, _| {
+            config.sections.contains_key(key)
+        });
+        Ok(())
+    }
+
     fn open_with_path(store_name: &str, path: &Path, config: DataStoreConfig) -> Result<Self, Error> {
         let chunk_store = ChunkStore::open(store_name, path)?;
 

src/bin/proxmox-backup-proxy.rs

@@ -136,6 +136,17 @@ async fn run() -> Result<(), Error> {
         },
     )?;
 
+    // to remove references for not configured datastores
+    commando_sock.register_command(
+        "datastore-removed".to_string(),
+        |_value| {
+            if let Err(err) = proxmox_backup::backup::DataStore::remove_unused_datastores() {
+                log::error!("could not refresh datastores: {}", err);
+            }
+            Ok(Value::Null)
+        }
+    )?;
+
     let server = daemon::create_daemon(
         ([0,0,0,0,0,0,0,0], 8007).into(),
         move |listener, ready| {

src/server.rs

@@ -100,3 +100,11 @@ pub(crate) async fn reload_proxy_certificate() -> Result<(), Error> {
         .await?;
     Ok(())
 }
+
+pub(crate) async fn notify_datastore_removed() -> Result<(), Error> {
+    let proxy_pid = crate::server::read_pid(buildcfg::PROXMOX_BACKUP_PROXY_PID_FN)?;
+    let sock = crate::server::ctrl_sock_from_pid(proxy_pid);
+    let _: Value = crate::server::send_raw_command(sock, "{\"command\":\"datastore-removed\"}\n")
+        .await?;
+    Ok(())
+}