[pbs-devel] [PATCH proxmox-backup v2 4/6] api: admin: factor out locking and maintenance mode clearing

[Christian Ebner]

Provide a helper which allows to either clear the maintenance mode if
the worker was aborted, or call the provided callback while holding
the datastore config lock.

In preparation for reusing the same logic for the s3 refresh.

Signed-off-by: Christian Ebner <c.ebner at proxmox.com>
---
changes since version 1:
- not present in previous version

 src/api2/admin/datastore.rs | 50 +++++++++++++++++++++++++------------
 1 file changed, 34 insertions(+), 16 deletions(-)

diff --git a/src/api2/admin/datastore.rs b/src/api2/admin/datastore.rs
index 7daccf9fd..8d58b5059 100644
--- a/src/api2/admin/datastore.rs
+++ b/src/api2/admin/datastore.rs
@@ -2584,7 +2584,6 @@ fn do_unmount_device(
     if datastore.backing_device.is_none() {
         bail!("can't unmount non-removable datastore");
     }
-    let mount_point = datastore.absolute_path();
 
     let mut old_status = String::new();
     let aborted = wait_on_active_operations(
@@ -2602,21 +2601,14 @@ fn do_unmount_device(
         },
     )?;
 
-    if aborted || worker.is_some_and(|w| w.abort_requested()) {
-        let _ = expect_maintenance_type(&datastore.name, MaintenanceType::Unmount)
-            .inspect_err(|e| warn!("maintenance mode was not as expected: {e}"))
-            .and_then(|(lock, config)| {
-                unset_maintenance(lock, config)
-                    .inspect_err(|e| warn!("could not reset maintenance mode: {e}"))
-            });
-        bail!("aborted, due to user request");
-    } else {
-        let (lock, config) = expect_maintenance_type(&datastore.name, MaintenanceType::Unmount)?;
-        crate::tools::disks::unmount_by_mountpoint(Path::new(&mount_point))?;
-        unset_maintenance(lock, config)
-            .map_err(|e| format_err!("could not reset maintenance mode: {e}"))?;
-    }
-    Ok(())
+    let mount_point = datastore.absolute_path();
+    clear_or_run_maintenance_locked(
+        &datastore.name,
+        worker,
+        MaintenanceType::Unmount,
+        aborted,
+        || crate::tools::disks::unmount_by_mountpoint(Path::new(&mount_point)),
+    )
 }
 
 #[api(
@@ -2747,6 +2739,32 @@ fn wait_on_active_operations(
     Ok(false)
 }
 
+// Either clear the current maintenance mode if the worker was aborted or run the provided callback
+// while keeping the datastore config lock, so the mode cannot be altered. Clears the maintenance
+// mode after successful callback execution.
+fn clear_or_run_maintenance_locked(
+    store: &str,
+    worker: Option<&dyn WorkerTaskContext>,
+    maintenance_expected: MaintenanceType,
+    aborted: bool,
+    callback: impl Fn() -> Result<(), Error>,
+) -> Result<(), Error> {
+    if aborted || worker.is_some_and(|w| w.abort_requested()) {
+        let _ = expect_maintenance_type(store, maintenance_expected)
+            .inspect_err(|e| warn!("maintenance mode was not as expected: {e}"))
+            .and_then(|(lock, config)| {
+                unset_maintenance(lock, config)
+                    .inspect_err(|e| warn!("could not reset maintenance mode: {e}"))
+            });
+        bail!("aborted, due to user request");
+    } else {
+        let (lock, config) = expect_maintenance_type(store, maintenance_expected)?;
+        callback()?;
+        unset_maintenance(lock, config)
+            .map_err(|e| format_err!("could not reset maintenance mode: {e}"))
+    }
+}
+
 #[sortable]
 const DATASTORE_INFO_SUBDIRS: SubdirMap = &[
     (
-- 
2.47.3