[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 <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

fs/fuse/file.c

···
 	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;