tyler/proxmox-backup
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backup: use shared flock for base snapshot

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To allow other reading operations on the base snapshot as well. No
semantic changes with this patch alone, as all other locks on snapshots
are exclusive.

Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
This commit is contained in:
Stefan Reiter 2020-10-14 14:16:31 +02:00 committed by Dietmar Maurer
parent f153930066
commit 7d6c4c39e9
2 changed files with 23 additions and 3 deletions
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4
src/api2/backup.rs
View File

@ -16,7 +16,7 @@ use crate::backup::*;
use crate::api2::types::*;
use crate::config::acl::PRIV_DATASTORE_BACKUP;
use crate::config::cached_user_info::CachedUserInfo;
use crate::tools::fs::lock_dir_noblock;
use crate::tools::fs::lock_dir_noblock_shared;
mod environment;
use environment::*;
@ -144,7 +144,7 @@ async move {
// lock last snapshot to prevent forgetting/pruning it during backup
let full_path = datastore.snapshot_path(&last.backup_dir);
Some(lock_dir_noblock(&full_path, "snapshot", "base snapshot is already locked by another operation")?)
Some(lock_dir_noblock_shared(&full_path, "snapshot", "base snapshot is already locked by another operation")?)
} else {
None
};

22
src/tools/fs.rs
View File

@ -265,11 +265,31 @@ impl Default for FSXAttr {
}
}
/// Attempt to acquire a shared flock on the given path, 'what' and
/// 'would_block_message' are used for error formatting.
pub fn lock_dir_noblock_shared(
path: &std::path::Path,
what: &str,
would_block_msg: &str,
) -> Result<DirLockGuard, Error> {
do_lock_dir_noblock(path, what, would_block_msg, false)
}
/// Attempt to acquire an exclusive flock on the given path, 'what' and
/// 'would_block_message' are used for error formatting.
pub fn lock_dir_noblock(
path: &std::path::Path,
what: &str,
would_block_msg: &str,
) -> Result<DirLockGuard, Error> {
do_lock_dir_noblock(path, what, would_block_msg, true)
}
fn do_lock_dir_noblock(
path: &std::path::Path,
what: &str,
would_block_msg: &str,
exclusive: bool,
) -> Result<DirLockGuard, Error> {
let mut handle = Dir::open(path, OFlag::O_RDONLY, Mode::empty())
.map_err(|err| {
@ -278,7 +298,7 @@ pub fn lock_dir_noblock(
// 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)))
proxmox::tools::fs::lock_file(&mut handle, exclusive, Some(std::time::Duration::from_nanos(0)))
.map_err(|err| {
format_err!(
"unable to acquire lock on {} directory {:?} - {}", what, path,