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};