From: Stefan Reiter <s.reiter@proxmox.com>
To: pbs-devel@lists.proxmox.com
Subject: [pbs-devel] [PATCH v2 proxmox-backup 1/7] src/tools/fs.rs: new helper lock_dir_noblock
Date: Tue, 11 Aug 2020 10:50:36 +0200 [thread overview]
Message-ID: <20200811085042.30686-2-s.reiter@proxmox.com> (raw)
In-Reply-To: <20200811085042.30686-1-s.reiter@proxmox.com>
From: Dietmar Maurer <dietmar@proxmox.com>
Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
---
src/tools/fs.rs | 39 ++++++++++++++++++++++++++++++++++++---
1 file changed, 36 insertions(+), 3 deletions(-)
diff --git a/src/tools/fs.rs b/src/tools/fs.rs
index ff625d30..5aaaecda 100644
--- a/src/tools/fs.rs
+++ b/src/tools/fs.rs
@@ -7,10 +7,18 @@ use std::os::unix::io::{AsRawFd, RawFd};
use anyhow::{format_err, Error};
use nix::dir;
use nix::dir::Dir;
+use nix::fcntl::OFlag;
+use nix::sys::stat::Mode;
+
use regex::Regex;
+use proxmox::sys::error::SysError;
+
+
use crate::tools::borrow::Tied;
+pub type DirLockGuard = Dir;
+
/// This wraps nix::dir::Entry with the parent directory's file descriptor.
pub struct ReadDirEntry {
entry: dir::Entry,
@@ -94,9 +102,6 @@ impl Iterator for ReadDir {
/// Create an iterator over sub directory entries.
/// This uses `openat` on `dirfd`, so `path` can be relative to that or an absolute path.
pub fn read_subdir<P: ?Sized + nix::NixPath>(dirfd: RawFd, path: &P) -> nix::Result<ReadDir> {
- use nix::fcntl::OFlag;
- use nix::sys::stat::Mode;
-
let dir = Dir::openat(dirfd, path, OFlag::O_RDONLY, Mode::empty())?;
let fd = dir.as_raw_fd();
let iter = Tied::new(dir, |dir| {
@@ -259,3 +264,31 @@ impl Default for FSXAttr {
}
}
}
+
+
+pub fn lock_dir_noblock(
+ path: &std::path::Path,
+ what: &str,
+ would_block_msg: &str,
+) -> Result<DirLockGuard, Error> {
+ let mut handle = Dir::open(path, OFlag::O_RDONLY, Mode::empty())
+ .map_err(|err| {
+ format_err!("unable to open {} directory {:?} for locking - {}", what, path, err)
+ })?;
+
+ // acquire in non-blocking mode, no point in waiting here since other
+ // backups could still take a very long time
+ proxmox::tools::fs::lock_file(&mut handle, true, Some(std::time::Duration::from_nanos(0)))
+ .map_err(|err| {
+ format_err!(
+ "unable to acquire lock on {} directory {:?} - {}", what, path,
+ if err.would_block() {
+ String::from(would_block_msg)
+ } else {
+ err.to_string()
+ }
+ )
+ })?;
+
+ Ok(handle)
+}
--
2.20.1
next prev parent reply other threads:[~2020-08-11 8:51 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-11 8:50 [pbs-devel] [PATCH v2 0/7] More flocking and race elimination Stefan Reiter
2020-08-11 8:50 ` Stefan Reiter [this message]
2020-08-11 8:50 ` [pbs-devel] [PATCH v2 proxmox-backup 2/7] src/backup/backup_info.rs: remove BackupGroup lock() Stefan Reiter
2020-08-11 8:50 ` [pbs-devel] [PATCH v2 proxmox-backup 3/7] datastore: prevent in-use deletion with locks instead of heuristic Stefan Reiter
2020-08-11 8:50 ` [pbs-devel] [PATCH v2 proxmox-backup 4/7] backup: flock snapshot on backup start Stefan Reiter
2020-08-11 8:50 ` [pbs-devel] [PATCH v2 proxmox-backup 5/7] Revert "backup: ensure base snapshots are still available after backup" Stefan Reiter
2020-08-11 8:50 ` [pbs-devel] [PATCH v2 proxmox-backup 6/7] backup: lock base snapshot and ensure existance on finish Stefan Reiter
2020-08-11 8:50 ` [pbs-devel] [PATCH v2 proxmox-backup 7/7] prune: also check backup snapshot locks Stefan Reiter
2020-08-11 9:35 ` Dietmar Maurer
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