From 77c2e4668b9aefcb817d2164d3a4bd4df7a2bd39 Mon Sep 17 00:00:00 2001
From: Dietmar Maurer <dietmar@proxmox.com>
Date: Mon, 18 Oct 2021 14:52:27 +0200
Subject: [PATCH] proxmox-rrd: use fine grained locking in commit_journal_impl

Aquire the rrd_map lock for each file (else we block access for a long time)
---
 proxmox-rrd/src/cache.rs         | 18 +++++++++++++++++-
 proxmox-rrd/src/cache/rrd_map.rs | 31 ++++++++++++++-----------------
 2 files changed, 31 insertions(+), 18 deletions(-)

diff --git a/proxmox-rrd/src/cache.rs b/proxmox-rrd/src/cache.rs
index 0fd49d72..faeae89f 100644
--- a/proxmox-rrd/src/cache.rs
+++ b/proxmox-rrd/src/cache.rs
@@ -152,6 +152,7 @@ impl RRDCache {
         let state = Arc::clone(&self.state);
         let rrd_map = Arc::clone(&self.rrd_map);
 
+
         let mut state_guard = self.state.write().unwrap();
         let journal_applied = state_guard.journal_applied;
 
@@ -372,8 +373,23 @@ fn commit_journal_impl(
     rrd_map: Arc<RwLock<RRDMap>>,
 ) -> Result<usize, Error> {
 
+    let files = rrd_map.read().unwrap().file_list();
+
+    let mut rrd_file_count = 0;
+    let mut errors = 0;
+
     // save all RRDs - we only need a read lock here
-    let rrd_file_count = rrd_map.read().unwrap().flush_rrd_files()?;
+    for rel_path in files.iter() {
+        rrd_file_count += 1;
+        if let Err(err) = rrd_map.read().unwrap().flush_rrd_file(&rel_path) {
+            errors += 1;
+            log::error!("unable to save rrd {}: {}", rel_path, err);
+        }
+    }
+
+    if errors != 0 {
+        bail!("errors during rrd flush - unable to commit rrd journal");
+    }
 
     // if everything went ok, remove the old journal files
     state.write().unwrap().remove_old_journals()?;
diff --git a/proxmox-rrd/src/cache/rrd_map.rs b/proxmox-rrd/src/cache/rrd_map.rs
index 27c5ae1c..c271c075 100644
--- a/proxmox-rrd/src/cache/rrd_map.rs
+++ b/proxmox-rrd/src/cache/rrd_map.rs
@@ -60,27 +60,24 @@ impl RRDMap {
         Ok(())
     }
 
-    pub fn flush_rrd_files(&self) -> Result<usize, Error> {
-        let mut rrd_file_count = 0;
+    pub fn file_list(&self) -> Vec<String> {
+        let mut list = Vec::new();
 
-        let mut errors = 0;
-        for (rel_path, rrd) in self.map.iter() {
-            rrd_file_count += 1;
-
-            let mut path = self.config.basedir.clone();
-            path.push(&rel_path);
-
-            if let Err(err) = rrd.save(&path, self.config.file_options.clone()) {
-                errors += 1;
-                log::error!("unable to save {:?}: {}", path, err);
-            }
+        for rel_path in self.map.keys() {
+            list.push(rel_path.clone());
         }
 
-        if errors != 0 {
-            bail!("errors during rrd flush - unable to commit rrd journal");
-        }
+        list
+    }
 
-        Ok(rrd_file_count)
+    pub fn flush_rrd_file(&self, rel_path: &str) -> Result<(), Error> {
+        if let Some(rrd) =  self.map.get(rel_path) {
+            let mut path = self.config.basedir.clone();
+            path.push(rel_path);
+            rrd.save(&path, self.config.file_options.clone())
+        } else {
+            bail!("rrd file {} not loaded", rel_path);
+        }
     }
 
     pub fn extract_cached_data(
-- 
2.39.5