From ba1b8533a57dc2ff1d5e3822aa575d15e7e35dcf Mon Sep 17 00:00:00 2001
From: Max Kellermann <max.kellermann@gmail.com>
Date: Mon, 13 May 2024 16:39:46 +0200
Subject: [PATCH] lib/nfs/Connection: fix assertion failure on mount timeout

When nfs_destroy_context() is called while nfs_mount_async() is in
progress, libnfs invokes MountCallback(-EINTR) (but only if a NFS RPC
call is in progress; if the TCP connect is in progress, that callback
is not invoked).

If the mount operation had timed out, OnMountTimeout() set
mount_state=FINISHED, which triggered an assertion failure in
MountCallback(); this commit adds a check on whether the mount has
timed out and ignores the MountCallback.
---
 src/lib/nfs/Connection.cxx | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/lib/nfs/Connection.cxx b/src/lib/nfs/Connection.cxx
index c07b545cb..db23ec1fb 100644
--- a/src/lib/nfs/Connection.cxx
+++ b/src/lib/nfs/Connection.cxx
@@ -195,6 +195,12 @@ NfsConnection::~NfsConnection() noexcept
 	assert(context != nullptr);
 
 	socket_event.ReleaseSocket();
+
+	/* cancel the timer before calling nfs_destroy_context() so
+	   MountCallback() knows the mount call is being canceled;
+	   checking status==-EINTR would be ambiguous */
+	mount_timeout_event.Cancel();
+
 	nfs_destroy_context(context);
 }
 
@@ -533,6 +539,15 @@ NfsConnection::MountCallback(int status, [[maybe_unused]] nfs_context *nfs,
 {
 	assert(GetEventLoop().IsInside());
 	assert(context == nfs);
+
+	if (!mount_timeout_event.IsPending()) {
+		/* called by nfs_destroy_context() while destructing
+		   this NfsConnection instance */
+		assert(status == -EINTR);
+		assert(mount_state == MountState::FINISHED);
+		return;
+	}
+
 	assert(mount_state == MountState::WAITING);
 
 	mount_state = MountState::FINISHED;