From: Dave Hansen 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: Christoph Hellwig Signed-off-by: Dave Hansen Signed-off-by: Andrew Morton --- fs/open.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff -puN fs/open.c~r-o-bind-mounts-make-access-use-mnt-check fs/open.c --- a/fs/open.c~r-o-bind-mounts-make-access-use-mnt-check +++ a/fs/open.c @@ -457,8 +457,17 @@ asmlinkage long sys_faccessat(int dfd, c if(res || !(mode & S_IWOTH) || special_file(nd.dentry->d_inode->i_mode)) goto out_path_release; - - if(IS_RDONLY(nd.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.mnt)) res = -EROFS; out_path_release: _