[pbs-devel] [PATCH proxmox-backup 2/2] backup/datastore: move manifest locking to /run

[Dominik Csapak <d.csapak@proxmox.com>]

this fixes the issue that on some filesystems, you cannot recursively
remove a directory when you hold a lock on a file inside (e.g. nfs/cifs)

it is not really backwards compatible (so during an upgrade, there
could be two daemons have the lock), but since the locking was
broken before (see previous patch) it should not really matter
(also it seems very unlikely that someone will trigger this)

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
---
 src/backup/datastore.rs | 26 +++++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/src/backup/datastore.rs b/src/backup/datastore.rs
index 0f74ac3c..9cc88906 100644
--- a/src/backup/datastore.rs
+++ b/src/backup/datastore.rs
@@ -257,6 +257,12 @@ impl DataStore {
                 )
             })?;
 
+        // the manifest does not exists anymore, we do not need to keep the lock
+        if let Ok(path) = self.manifest_lock_path(backup_dir) {
+            // ignore errors
+            let _ = std::fs::remove_file(path);
+        }
+
         Ok(())
     }
 
@@ -698,13 +704,27 @@ impl DataStore {
         ))
     }
 
+    fn manifest_lock_path(
+        &self,
+        backup_dir: &BackupDir,
+    ) -> Result<PathBuf, Error> {
+
+        let mut path = PathBuf::from("/run/proxmox-backup/.locks/");
+        path.push(self.name());
+        path.push(backup_dir.group().backup_type());
+        path.push(backup_dir.group().backup_id());
+        std::fs::create_dir_all(&path)?;
+
+        path.push(format!( "{}{}", backup_dir.backup_time_string(), &MANIFEST_LOCK_NAME));
+
+        Ok(path)
+    }
+
     fn lock_manifest(
         &self,
         backup_dir: &BackupDir,
     ) -> Result<File, Error> {
-        let mut path = self.base_path();
-        path.push(backup_dir.relative_path());
-        path.push(&MANIFEST_LOCK_NAME);
+        let path = self.manifest_lock_path(backup_dir)?;
 
         // update_manifest should never take a long time, so if someone else has
         // the lock we can simply block a bit and should get it soon
-- 
2.20.1