svn commit: r268008 - head/sys/fs/nfsclient

[Rick Macklem]

Author: rmacklem
Date: Sat Jun 28 21:47:15 2014
New Revision: 268008
URL: http://svnweb.freebsd.org/changeset/base/268008

Log:
  There might be a potential race condition for the NFSv4 client
  when a newly created file has another open done on it that
  update the open mode. This patch moves the code that updates
  the open mode up into the block where the mutex is held to
  ensure this cannot happen. No bug caused by this potential
  race has been observed, but this fix is a safety belt to ensure
  it cannot happen.
  
  MFC after:	2 weeks

Modified:
  head/sys/fs/nfsclient/nfs_clstate.c

Modified: head/sys/fs/nfsclient/nfs_clstate.c
==============================================================================
--- head/sys/fs/nfsclient/nfs_clstate.c	Sat Jun 28 19:59:12 2014	(r268007)
+++ head/sys/fs/nfsclient/nfs_clstate.c	Sat Jun 28 21:47:15 2014	(r268008)
@@ -281,6 +281,23 @@ nfscl_open(vnode_t vp, u_int8_t *nfhp, i
 	    newonep);
 
 	/*
+	 * Now, check the mode on the open and return the appropriate
+	 * value.
+	 */
+	if (retp != NULL) {
+		if (nfhp != NULL && dp != NULL && nop == NULL)
+			/* new local open on delegation */
+			*retp = NFSCLOPEN_SETCRED;
+		else
+			*retp = NFSCLOPEN_OK;
+	}
+	if (op != NULL && (amode & ~(op->nfso_mode))) {
+		op->nfso_mode |= amode;
+		if (retp != NULL && dp == NULL)
+			*retp = NFSCLOPEN_DOOPEN;
+	}
+
+	/*
 	 * Serialize modifications to the open owner for multiple threads
 	 * within the same process using a read/write sleep lock.
 	 */
@@ -295,23 +312,6 @@ nfscl_open(vnode_t vp, u_int8_t *nfhp, i
 		*owpp = owp;
 	if (opp != NULL)
 		*opp = op;
-	if (retp != NULL) {
-		if (nfhp != NULL && dp != NULL && nop == NULL)
-			/* new local open on delegation */
-			*retp = NFSCLOPEN_SETCRED;
-		else
-			*retp = NFSCLOPEN_OK;
-	}
-
-	/*
-	 * Now, check the mode on the open and return the appropriate
-	 * value.
-	 */
-	if (op != NULL && (amode & ~(op->nfso_mode))) {
-		op->nfso_mode |= amode;
-		if (retp != NULL && dp == NULL)
-			*retp = NFSCLOPEN_DOOPEN;
-	}
 	return (0);
 }