[PATCH] fuse: check O_DIRECT

Check O_DIRECT and return -EINVAL error in open.  dentry_open() also checks
this but only after the open method is called.  This patch optimizes away
the unnecessary upcalls in this case.

It could be a correctness issue too: if filesystem has open() with side
effect, then it should fail before doing the open, not after.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/fuse/file.c

@@ -23,6 +23,10 @@ int fuse_open_common(struct inode *inode, struct file *file, int isdir)
 	struct fuse_file *ff;
 	int err;
 
+	/* VFS checks this, but only _after_ ->open() */
+	if (file->f_flags & O_DIRECT)
+		return -EINVAL;
+
 	err = generic_file_open(inode, file);
 	if (err)
 		return err;