proxmox-rrd: use syncfs after writing rrd files

Signed-off-by: Dietmar Maurer <dietmar@proxmox.com>

proxmox-rrd/Cargo.toml

@@ -12,6 +12,7 @@ proxmox-router = "1.1"
 anyhow = "1.0"
 bitflags = "1.2.1"
 crossbeam-channel = "0.5"
+libc = "0.2"
 log = "0.4"
 nix = "0.19.1"
 serde = { version = "1.0", features = ["derive"] }

proxmox-rrd/src/cache.rs

@@ -147,6 +147,10 @@ impl RRDCache {
         Ok(JournalEntry { time, value, dst, rel_path })
     }
 
+    pub fn sync_journal(&self) -> Result<(), Error> {
+        self.state.read().unwrap().sync_journal()
+    }
+
     /// Apply and commit the journal. Should be used at server startup.
     pub fn apply_journal(&self) -> Result<bool, Error> {
         let state = Arc::clone(&self.state);
@@ -387,6 +391,8 @@ fn commit_journal_impl(
         }
     }
 
+    state.read().unwrap().syncfs()?;
+
     if errors != 0 {
         bail!("errors during rrd flush - unable to commit rrd journal");
     }

proxmox-rrd/src/cache/journal.rs

@@ -3,6 +3,7 @@ use std::path::PathBuf;
 use std::sync::Arc;
 use std::io::{Write, BufReader};
 use std::ffi::OsStr;
+use std::os::unix::io::AsRawFd;
 
 use anyhow::Error;
 use nix::fcntl::OFlag;
@@ -50,6 +51,16 @@ impl JournalState {
         })
     }
 
+    pub fn sync_journal(&self) -> Result<(), Error> {
+        nix::unistd::fdatasync(self.journal.as_raw_fd())?;
+        Ok(())
+    }
+
+    pub fn syncfs(&self) -> Result<(), nix::Error> {
+        let res = unsafe { libc::syncfs(self.journal.as_raw_fd()) };
+        nix::errno::Errno::result(res).map(drop)
+    }
+
     pub fn append_journal_entry(
         &mut self,
         time: f64,

proxmox-rrd/src/rrd.rs

@@ -14,7 +14,6 @@
 use std::path::Path;
 
 use anyhow::{bail, format_err, Error};
-
 use serde::{Serialize, Deserialize};
 
 use proxmox::tools::fs::{replace_file, CreateOptions};

src/bin/proxmox-backup-proxy.rs

@@ -30,7 +30,9 @@ use proxmox_rest_server::{
     ServerAdapter, WorkerTask, cleanup_old_tasks,
 };
 
-use proxmox_backup::rrd_cache::{ rrd_update_gauge, rrd_update_derive, initialize_rrd_cache};
+use proxmox_backup::rrd_cache::{
+    initialize_rrd_cache, rrd_update_gauge, rrd_update_derive, rrd_sync_journal,
+};
 use proxmox_backup::{
     server::{
         auth::check_pbs_auth,
@@ -896,6 +898,8 @@ async fn run_stat_generator() {
 
         generate_host_stats().await;
 
+        rrd_sync_journal();
+
         tokio::time::sleep_until(tokio::time::Instant::from_std(delay_target)).await;
 
      }

src/rrd_cache.rs

@@ -94,6 +94,14 @@ pub fn extract_rrd_data(
     rrd_cache.extract_cached_data(basedir, name, cf, resolution, Some(start), Some(end))
 }
 
+/// Sync/Flush the RRD journal
+pub fn rrd_sync_journal() {
+    if let Ok(rrd_cache) = get_rrd_cache() {
+        if let Err(err) = rrd_cache.sync_journal() {
+            log::error!("rrd_sync_journal failed - {}", err);
+        }
+    }
+}
 /// Update RRD Gauge values
 pub fn rrd_update_gauge(name: &str, value: f64) {
     if let Ok(rrd_cache) = get_rrd_cache() {