[pbs-devel] [PATCH proxmox-backup v3 1/4] pbs-config: add token.shadow generation to ConfigVersionCache

[Samuel Rufinatscha]

Currently, every token-based API request reads the token.shadow file and
runs the expensive password hash verification for the given token
secret. This shows up as a hotspot in /status profiling (see
bug #7017 [1]).

To solve the issue, this patch prepares the config version cache,
so that token_shadow_generation config caching can be built on
top of it.

This patch specifically:
(1) implements increment function in order to invalidate generations

This patch is part of the series which fixes bug #7017 [1].

[1] https://bugzilla.proxmox.com/show_bug.cgi?id=7017

Signed-off-by: Samuel Rufinatscha <s.rufinatscha at proxmox.com>
---
 pbs-config/src/config_version_cache.rs | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/pbs-config/src/config_version_cache.rs b/pbs-config/src/config_version_cache.rs
index e8fb994f..1376b11d 100644
--- a/pbs-config/src/config_version_cache.rs
+++ b/pbs-config/src/config_version_cache.rs
@@ -28,6 +28,8 @@ struct ConfigVersionCacheDataInner {
     // datastore (datastore.cfg) generation/version
     // FIXME: remove with PBS 3.0
     datastore_generation: AtomicUsize,
+    // Token shadow (token.shadow) generation/version.
+    token_shadow_generation: AtomicUsize,
     // Add further atomics here
 }
 
@@ -153,4 +155,20 @@ impl ConfigVersionCache {
             .datastore_generation
             .fetch_add(1, Ordering::AcqRel)
     }
+
+    /// Returns the token shadow generation number.
+    pub fn token_shadow_generation(&self) -> usize {
+        self.shmem
+            .data()
+            .token_shadow_generation
+            .load(Ordering::Acquire)
+    }
+
+    /// Increase the token shadow generation number.
+    pub fn increase_token_shadow_generation(&self) -> usize {
+        self.shmem
+            .data()
+            .token_shadow_generation
+            .fetch_add(1, Ordering::AcqRel)
+    }
 }
-- 
2.47.3