[PATCH proxmox-backup 3/5] bin: proxy: periodically schedule fstrim on datastore's filesystems

[Christian Ebner <c.ebner@proxmox.com>]

Run the fstrim command as scheduled job on datastores having a
schedule defined in the config.

This is done since by default the systemd service to execute fstrim
invokes the command with:

`/sbin/fstrim --listed-in /etc/fstab:/proc/self/mountinfo ...`

which however does not cover datastores created on top of a disk,
since these are mounted via systemd mount units. fstrim however only
evaluates the given list above up to the first non-empty file as
stated in the man page [0].

[0] https://www.man7.org/linux/man-pages/man8/fstrim.8.html

Fixes: https://forum.proxmox.com/threads/181764/
Signed-off-by: Christian Ebner <c.ebner@proxmox.com>
---
 src/bin/proxmox-backup-proxy.rs | 59 +++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/src/bin/proxmox-backup-proxy.rs b/src/bin/proxmox-backup-proxy.rs
index c1fe3ac15..1d375e69d 100644
--- a/src/bin/proxmox-backup-proxy.rs
+++ b/src/bin/proxmox-backup-proxy.rs
@@ -508,6 +508,7 @@ async fn schedule_tasks() -> Result<(), Error> {
     schedule_datastore_verify_jobs().await;
     schedule_tape_backup_jobs().await;
     schedule_task_log_rotate().await;
+    schedule_fstrim().await;
 
     Ok(())
 }
@@ -879,6 +880,64 @@ async fn schedule_task_log_rotate() {
     }
 }
 
+async fn schedule_fstrim() {
+    let config = match pbs_config::datastore::config() {
+        Err(err) => {
+            eprintln!("unable to read datastore config - {err}");
+            return;
+        }
+        Ok((config, _digest)) => config,
+    };
+
+    for (store, (_, store_config)) in config.sections {
+        let store_config: DataStoreConfig = match serde_json::from_value(store_config) {
+            Ok(c) => c,
+            Err(err) => {
+                eprintln!("datastore config from_value failed - {err}");
+                continue;
+            }
+        };
+
+        let event_schedule = match &store_config.fstrim_schedule {
+            Some(event_schedule) => event_schedule,
+            None => continue,
+        };
+
+        let worker_type = "fstrim";
+        if check_schedule(worker_type, event_schedule, &store) {
+            let mut job = match Job::new(worker_type, &store) {
+                Ok(job) => job,
+                Err(_) => continue, // could not get lock
+            };
+
+            if let Err(err) = WorkerTask::new_thread(
+                worker_type,
+                None,
+                Authid::root_auth_id().to_string(),
+                false,
+                move |worker| {
+                    job.start(&worker.upid().to_string())?;
+                    info!("executing fstrim on filesystem for {store}");
+
+                    let path = store_config.absolute_path();
+                    let result = proxmox_backup::tools::disks::fstrim(Path::new(&path))
+                        .map(|output| log::info!("{output}"));
+
+                    let status = worker.create_state(&result);
+
+                    if let Err(err) = job.finish(status) {
+                        eprintln!("could not finish job state for {worker_type}: {err}");
+                    }
+
+                    result
+                },
+            ) {
+                eprintln!("unable to start fstrim task: {err}");
+            }
+        }
+    }
+}
+
 async fn command_reopen_access_logfiles() -> Result<(), Error> {
     // only care about the most recent daemon instance for each, proxy & api, as other older ones
     // should not respond to new requests anyway, but only finish their current one and then exit.
-- 
2.47.3