From 63a483ed5f4eaadb8979992c7a5de24c7a471c61 Mon Sep 17 00:00:00 2001
From: jeff <jeff@FreeBSD.org>
Date: Mon, 26 Mar 2018 18:36:17 +0000
Subject: [PATCH] Fix a bug introduced in r329612 that slowly invalidates all
 clean bufs.

Reported by:	bde
Reviewed by:	bde
Sponsored by:	Netflix, Dell/EMC Isilon
---
 sys/kern/vfs_bio.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index ea0a3f010b14..2022289767b2 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -821,7 +821,8 @@ bufspace_daemon(void *arg)
 		 *	which will inefficiently trade bufs with bqrelse
 		 *	until we return to condition 2.
 		 */
-		do {
+		while (bd->bd_bufspace > bd->bd_lobufspace ||
+		    bd->bd_freebuffers < bd->bd_hifreebuffers) {
 			if (buf_recycle(bd, false) != 0) {
 				if (bd_flushall(bd))
 					continue;
@@ -842,9 +843,7 @@ bufspace_daemon(void *arg)
 					BD_UNLOCK(bd);
 			}
 			maybe_yield();
-		} while (bd->bd_bufspace > bd->bd_lobufspace ||
-		    bd->bd_freebuffers < bd->bd_hifreebuffers);
-
+		}
 		bufspace_daemon_wait(bd);
 	}
 }