[pbs-devel] [PATCH proxmox-backup v13 11/26] add auto-mounting for removable datastores

[Hannes Laimer]

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 at proxmox.com>
---
changes since v12:
 * make service not dynamic
 * don't logs UUIDs that don't contains known datastores

 debian/proxmox-backup-server.install        |  1 +
 debian/proxmox-backup-server.udev           |  3 +
 etc/Makefile                                |  3 +-
 etc/removable-device-attach at .service        |  8 +++
 src/bin/proxmox_backup_manager/datastore.rs | 62 ++++++++++++++++++++-
 5 files changed, 75 insertions(+), 2 deletions(-)
 create mode 100644 etc/removable-device-attach at .service

diff --git a/debian/proxmox-backup-server.install b/debian/proxmox-backup-server.install
index 79757ead..ff581e3d 100644
--- a/debian/proxmox-backup-server.install
+++ b/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 at .service /lib/systemd/system/
 usr/bin/pmt
 usr/bin/pmtx
 usr/bin/proxmox-tape
diff --git a/debian/proxmox-backup-server.udev b/debian/proxmox-backup-server.udev
index afdfb2bc..e21b8bc7 100644
--- a/debian/proxmox-backup-server.udev
+++ b/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}"
\ No newline at end of file
diff --git a/etc/Makefile b/etc/Makefile
index 42f639f6..b206b9ca 100644
--- a/etc/Makefile
+++ b/etc/Makefile
@@ -2,12 +2,13 @@ include ../defines.mk
 
 UNITS := \
 	proxmox-backup-daily-update.timer \
+	removable-device-attach at .service \
 
 DYNAMIC_UNITS := \
 	proxmox-backup-banner.service \
 	proxmox-backup-daily-update.service \
 	proxmox-backup.service \
-	proxmox-backup-proxy.service
+	proxmox-backup-proxy.service \
 
 all: $(UNITS) $(DYNAMIC_UNITS) pbs-enterprise.list
 
diff --git a/etc/removable-device-attach at .service b/etc/removable-device-attach at .service
new file mode 100644
index 00000000..e10d1ea3
--- /dev/null
+++ b/etc/removable-device-attach at .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
diff --git a/src/bin/proxmox_backup_manager/datastore.rs b/src/bin/proxmox_backup_manager/datastore.rs
index f2795b39..05f35279 100644
--- a/src/bin/proxmox_backup_manager/datastore.rs
+++ b/src/bin/proxmox_backup_manager/datastore.rs
@@ -1,4 +1,4 @@
-use anyhow::{format_err, Error};
+use anyhow::{bail, format_err, Error};
 use serde_json::Value;
 
 use proxmox_router::{cli::*, ApiHandler, RpcEnvironment};
@@ -195,6 +195,62 @@ async fn delete_datastore(mut param: Value, rpcenv: &mut dyn RpcEnvironment) ->
     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 info = &api2::config::datastore::API_METHOD_LIST_DATASTORES;
+    let data: Value = match info.handler {
+        ApiHandler::Sync(handler) => (handler)(serde_json::json!({}), info, rpcenv)?,
+        _ => unreachable!(),
+    };
+
+    let matching_stores = data.as_array().map_or(Vec::new(), |list| {
+        list.iter()
+            .filter_map(Value::as_object)
+            .filter(|store| store.get("backing-device").map_or(false, |d| d.eq(&uuid)))
+            .collect()
+    });
+
+    if matching_stores.len() != 1 {
+        return Ok(Value::Null);
+    }
+
+    let store_name = matching_stores
+        .get(0)
+        .and_then(|s| s.get("name").and_then(Value::as_str));
+    if let Some(store_name) = store_name {
+        let info = &api2::admin::datastore::API_METHOD_MOUNT;
+        let mount_param = serde_json::json!({
+            "store": store_name,
+        });
+        let result = match info.handler {
+            ApiHandler::Sync(handler) => (handler)(mount_param, info, rpcenv)?,
+            _ => unreachable!(),
+        };
+        crate::wait_for_local_worker(result.as_str().unwrap()).await?;
+        return Ok(Value::Null);
+    }
+    bail!("'{uuid}' is not associated with any datastore")
+}
+
 pub fn datastore_commands() -> CommandLineInterface {
     let cmd_def = CliCommandMap::new()
         .insert("list", CliCommand::new(&API_METHOD_LIST_DATASTORES))
@@ -240,6 +296,10 @@ 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)
-- 
2.39.5