From 3a804a8a201f2b1f0c830329bd084e53851fb2a9 Mon Sep 17 00:00:00 2001 From: Stefan Reiter Date: Thu, 6 May 2021 17:26:22 +0200 Subject: [PATCH] file-restore-daemon: limit concurrent download calls While the issue with vsock packets starving kernel memory is mostly worked around by the '64k -> 4k buffer' patch in 'proxmox-backup-restore-image', let's be safe and also limit the number of concurrent transfers. 8 downloads per VM seems like a fair value. Signed-off-by: Stefan Reiter --- src/bin/proxmox_restore_daemon/api.rs | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/src/bin/proxmox_restore_daemon/api.rs b/src/bin/proxmox_restore_daemon/api.rs index c578b2c0..f2732e64 100644 --- a/src/bin/proxmox_restore_daemon/api.rs +++ b/src/bin/proxmox_restore_daemon/api.rs @@ -6,6 +6,7 @@ use hyper::{header, Body, Response, StatusCode}; use log::error; use pathpatterns::{MatchEntry, MatchPattern, MatchType, Pattern}; use serde_json::Value; +use tokio::sync::Semaphore; use std::ffi::OsStr; use std::fs; @@ -41,6 +42,8 @@ pub const ROUTER: Router = Router::new() .get(&list_subdirs_api_method!(SUBDIRS)) .subdirs(SUBDIRS); +static DOWNLOAD_SEM: Semaphore = Semaphore::const_new(8); + fn read_uptime() -> Result { let uptime = fs::read_to_string("/proc/uptime")?; // unwrap the Option, if /proc/uptime is empty we have bigger problems @@ -252,6 +255,12 @@ fn extract( let _inhibitor = watchdog_inhibit(); async move { let _inhibitor = _inhibitor; + + let _permit = match DOWNLOAD_SEM.try_acquire() { + Ok(permit) => permit, + Err(_) => bail!("maximum concurrent download limit reached, please wait for another restore to finish before attempting a new one"), + }; + let path = tools::required_string_param(¶m, "path")?; let mut path = base64::decode(path)?; if let Some(b'/') = path.last() { @@ -286,6 +295,7 @@ fn extract( if pxar { tokio::spawn(async move { let _inhibitor = _inhibitor; + let _permit = _permit; let result = async move { // pxar always expects a directory as it's root, so to accommodate files as // well we encode the parent dir with a filter only matching the target instead @@ -344,6 +354,7 @@ fn extract( } else { tokio::spawn(async move { let _inhibitor = _inhibitor; + let _permit = _permit; let result = async move { if vm_path.is_dir() { zip_directory(&mut writer, &vm_path).await?;