add auto-mounting for removable datastores

If a device houses multiple datastore, none of them will be mounted
automatically. If a device only contains a single datastore it will be
mounted automatically. The reason for not mounting multiple datastore
automatically is that we don't know which is actually wanted, and since
mounting all means also all have to be unmounted manually, it made sense
to have the user choose which to mount.

Signed-off-by: Hannes Laimer <h.laimer@proxmox.com>

debian/proxmox-backup-server.install

@@ -4,6 +4,7 @@ etc/proxmox-backup-daily-update.service /lib/systemd/system/
 etc/proxmox-backup-daily-update.timer /lib/systemd/system/
 etc/proxmox-backup-proxy.service /lib/systemd/system/
 etc/proxmox-backup.service /lib/systemd/system/
+etc/removable-device-attach@.service /lib/systemd/system/
 usr/bin/pmt
 usr/bin/pmtx
 usr/bin/proxmox-tape

debian/proxmox-backup-server.udev

@@ -16,3 +16,6 @@ SUBSYSTEM=="scsi_generic", SUBSYSTEMS=="scsi", ATTRS{type}=="1", ENV{ID_SCSI_SER
   SYMLINK+="tape/by-id/scsi-$env{ID_SCSI_SERIAL}-sg"
 
 LABEL="persistent_storage_tape_end"
+
+# triggers the mounting of a removable device
+ACTION=="add", SUBSYSTEM=="block", ENV{ID_FS_UUID}!="", TAG+="systemd", ENV{SYSTEMD_WANTS}="removable-device-attach@$env{ID_FS_UUID}"

etc/Makefile

@@ -2,6 +2,7 @@ include ../defines.mk
 
 UNITS := \
 	proxmox-backup-daily-update.timer \
+	removable-device-attach@.service
 
 DYNAMIC_UNITS := \
 	proxmox-backup-banner.service \

etc/removable-device-attach@.service

@@ -0,0 +1,8 @@
+[Unit]
+Description=Try to mount the removable device of a datastore with uuid '%i'.
+After=proxmox-backup-proxy.service
+Requires=proxmox-backup-proxy.service
+
+[Service]
+Type=simple
+ExecStart=/usr/sbin/proxmox-backup-manager datastore uuid-mount %i

src/bin/proxmox_backup_manager/datastore.rs

@@ -9,7 +9,7 @@ use proxmox_backup::api2;
 use proxmox_backup::api2::config::datastore::DeletableProperty;
 use proxmox_backup::client_helpers::connect_to_localhost;
 
-use anyhow::Error;
+use anyhow::{format_err, Error};
 use serde_json::Value;
 
 #[api(
@@ -244,6 +244,52 @@ async fn update_datastore(name: String, mut param: Value) -> Result<(), Error> {
     Ok(())
 }
 
+#[api(
+    protected: true,
+    input: {
+        properties: {
+            uuid: {
+                type: String,
+                description: "The UUID of the device that should be mounted",
+            },
+            "output-format": {
+                schema: OUTPUT_FORMAT,
+                optional: true,
+            },
+        },
+    },
+)]
+/// Try mounting a removable datastore given the UUID.
+async fn uuid_mount(param: Value, _rpcenv: &mut dyn RpcEnvironment) -> Result<Value, Error> {
+    let uuid = param["uuid"]
+        .as_str()
+        .ok_or_else(|| format_err!("uuid has to be specified"))?;
+
+    let (config, _digest) = pbs_config::datastore::config()?;
+    let list: Vec<DataStoreConfig> = config.convert_to_typed_array("datastore")?;
+    let matching_stores: Vec<DataStoreConfig> = list
+        .into_iter()
+        .filter(|store: &DataStoreConfig| {
+            store
+                .backing_device
+                .clone()
+                .map_or(false, |device| device.eq(&uuid))
+        })
+        .collect();
+
+    if matching_stores.len() != 1 {
+        return Ok(Value::Null);
+    }
+
+    if let Some(store) = matching_stores.get(0) {
+        api2::admin::datastore::do_mount_device(store.clone())?;
+    }
+
+    // we don't want to fail for UUIDs that are not associated with datastores, as that produces
+    // quite some noise in the logs, given this is check for every device that is plugged in.
+    Ok(Value::Null)
+}
+
 pub fn datastore_commands() -> CommandLineInterface {
     let cmd_def = CliCommandMap::new()
         .insert("list", CliCommand::new(&API_METHOD_LIST_DATASTORES))
@@ -289,6 +335,10 @@ pub fn datastore_commands() -> CommandLineInterface {
                     pbs_config::datastore::complete_calendar_event,
                 ),
         )
+        .insert(
+            "uuid-mount",
+            CliCommand::new(&API_METHOD_UUID_MOUNT).arg_param(&["uuid"]),
+        )
         .insert(
             "remove",
             CliCommand::new(&API_METHOD_DELETE_DATASTORE)