From bf9a6d0f4c2ae95610322056724a8a181da3d521 Mon Sep 17 00:00:00 2001
From: Yuchen Liang <yuchen@neon.tech>
Date: Mon, 2 Dec 2024 16:07:57 +0000
Subject: [PATCH] review: follow Buffer::extend_from_slice trait definition

panics if IoBufferMut does not enough capacity left to accomodate the source
buffer.

Signed-off-by: Yuchen Liang <yuchen@neon.tech>
---
 pageserver/src/virtual_file/owned_buffers_io/write.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/pageserver/src/virtual_file/owned_buffers_io/write.rs b/pageserver/src/virtual_file/owned_buffers_io/write.rs
index 51c711ab5a..20bf878123 100644
--- a/pageserver/src/virtual_file/owned_buffers_io/write.rs
+++ b/pageserver/src/virtual_file/owned_buffers_io/write.rs
@@ -1,7 +1,6 @@
 mod flush;
 use std::sync::Arc;
 
-use bytes::BytesMut;
 use flush::FlushHandle;
 use tokio_epoll_uring::IoBuf;
 
@@ -218,6 +217,10 @@ impl Buffer for IoBufferMut {
     }
 
     fn extend_from_slice(&mut self, other: &[u8]) {
+        if self.len() + other.len() > self.cap() {
+            panic!("Buffer capacity exceeded");
+        }
+
         IoBufferMut::extend_from_slice(self, other);
     }