From 19fb7eaf9faed3abf045ff604c41ccb8dfc240af Mon Sep 17 00:00:00 2001
From: kib <kib@FreeBSD.org>
Date: Tue, 28 Oct 2008 12:00:28 +0000
Subject: Provide an explanation for getinoquota() call in the ufs_access vop.

MFC after:	3 days
---
 sys/ufs/ufs/ufs_vnops.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/sys/ufs/ufs/ufs_vnops.c b/sys/ufs/ufs/ufs_vnops.c
index 40304bc..eb851cf 100644
--- a/sys/ufs/ufs/ufs_vnops.c
+++ b/sys/ufs/ufs/ufs_vnops.c
@@ -330,7 +330,18 @@ ufs_access(ap)
 			if (vp->v_mount->mnt_flag & MNT_RDONLY)
 				return (EROFS);
 #ifdef QUOTA
+			/*
+			 * Inode is accounted in the quotas only if struct
+			 * dquot is attached to it. VOP_ACCESS() is called
+			 * from vn_open_cred() and provides a convenient
+			 * point to call getinoquota().
+			 */
 			if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
+
+				/*
+				 * Upgrade vnode lock, since getinoquota()
+				 * requires exclusive lock to modify inode.
+				 */
 				relocked = 1;
 				vhold(vp);
 				vn_lock(vp, LK_UPGRADE | LK_RETRY);
-- 
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