From: Al Viro <viro@zeniv.linux.org.uk>
Date: Mon, 30 Jul 2012 07:50:30 +0000 (+0400)
Subject: fix O_EXCL handling for devices
X-Git-Tag: v3.6-rc1~18^2~30
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=f8310c59201b183ebee2e3fe0c7242f5729be0af;p=linux.git

fix O_EXCL handling for devices

O_EXCL without O_CREAT has different semantics; it's "fail if already opened",
not "fail if already exists".  commit 71574865 broke that...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---

diff --git a/fs/namei.c b/fs/namei.c
index 618d3531cf9f..e133bf3bbb03 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2418,7 +2418,7 @@ static int atomic_open(struct nameidata *nd, struct dentry *dentry,
 	if ((open_flag & O_CREAT) && !IS_POSIXACL(dir))
 		mode &= ~current_umask();
 
-	if (open_flag & O_EXCL) {
+	if ((open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT)) {
 		open_flag &= ~O_TRUNC;
 		*opened |= FILE_CREATED;
 	}
@@ -2742,7 +2742,7 @@ static int do_last(struct nameidata *nd, struct path *path,
 	}
 
 	error = -EEXIST;
-	if (open_flag & O_EXCL)
+	if ((open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT))
 		goto exit_dput;
 
 	error = follow_managed(path, nd->flags);