fuse: fix fileattr op failure

The fileattr API conversion broke lsattr on ntfs3g.

Previously the ioctl(... FS_IOC_GETFLAGS) returned an EINVAL error, but
after the conversion the error returned by the fuse filesystem was not
propagated back to the ioctl() system call, resulting in success being
returned with bogus values.

Fix by checking for outarg.result in fuse_priv_ioctl(), just as generic
ioctl code does.

Reported-by: Jean-Pierre André <[email protected]>
Fixes: 72227ea ("fuse: convert to fileattr")
Cc: <[email protected]> # v5.13
Signed-off-by: Miklos Szeredi <[email protected]>

Author: Miklos Szeredi

fs/fuse/ioctl.c

@@ -394,9 +394,12 @@ static int fuse_priv_ioctl(struct inode *inode, struct fuse_file *ff,
 	args.out_args[1].value = ptr;
 
 	err = fuse_simple_request(fm, &args);
-	if (!err && outarg.flags & FUSE_IOCTL_RETRY)
-		err = -EIO;
-
+	if (!err) {
+		if (outarg.result < 0)
+			err = outarg.result;
+		else if (outarg.flags & FUSE_IOCTL_RETRY)
+			err = -EIO;
+	}
 	return err;
 }