From 2f676cbc0d60ae806216c7a61c6971bd72dedde8 Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Fri, 15 Feb 2008 14:37:55 -0800 Subject: [PATCH] r/o bind mounts: make access() use new r/o helper It is OK to let access() go without using a mnt_want/drop_write() pair because it doesn't actually do writes to the filesystem, and it is inherently racy anyway. This is a rare case when it is OK to use __mnt_is_readonly() directly. Acked-by: Al Viro Signed-off-by: Christoph Hellwig Signed-off-by: Dave Hansen Signed-off-by: Andrew Morton Signed-off-by: Al Viro --- fs/open.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'fs') diff --git a/fs/open.c b/fs/open.c index 4d690e33446..e58382d57e7 100644 --- a/fs/open.c +++ b/fs/open.c @@ -459,8 +459,17 @@ asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode) if(res || !(mode & S_IWOTH) || special_file(nd.path.dentry->d_inode->i_mode)) goto out_path_release; - - if(IS_RDONLY(nd.path.dentry->d_inode)) + /* + * This is a rare case where using __mnt_is_readonly() + * is OK without a mnt_want/drop_write() pair. Since + * no actual write to the fs is performed here, we do + * not need to telegraph to that to anyone. + * + * By doing this, we accept that this access is + * inherently racy and know that the fs may change + * state before we even see this result. + */ + if (__mnt_is_readonly(nd.path.mnt)) res = -EROFS; out_path_release: -- cgit v1.2.3