From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C3AC3350288 for ; Tue, 23 Dec 2025 17:50:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.89.141.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766512242; cv=none; b=syO/P9BWfCd18bNjWGK668bbnU9hatuJEX9OLSowpCyLiMVqTwez2mMfsEvjq+7o68IR0LRfr+RV1PoK2pGMgT960RZ36bqlL6UpToWTLwPMHTB3NcmGiTaREdi040WISJCC0CFgIQw6oRATenZomjp3jZNtLZ+S7/zG/+Hpu2o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766512242; c=relaxed/simple; bh=1L0JcjKjUiZ0M6l7c2rIcSf6OFTJmW2mMmtZQzrsHVg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=G9TiMsfn0144LOMTeZQ1Ls+T1KYz9cQL8aHbJTctQfYdrP5+rc8T28HFYI0QQsZCHVgHzctjooE8lHLw25DJkEuV+ViCSskup61TrsGny0hgWiOMvRl4OmKyYGQfZHLS0vzJo7794QhVi2v1Xllhty0f5JsrDG7dDP0h1ZOBAY8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk; spf=none smtp.mailfrom=ftp.linux.org.uk; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b=cRGgJKOc; arc=none smtp.client-ip=62.89.141.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=ftp.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b="cRGgJKOc" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=V3xELkGb5rihbexLGeefbl/htIOV8XG31wmfQOflumo=; b=cRGgJKOc/pHSRuE2qN9OrRQQXL fhm4R6yZTRT2TUVUjjNN7cw037ZrlHet/NxVA0Y2FY/XiKm5RzldKm8JTLLa6X/YKT0nlvhLjj1ZV ktL4YQBhCguUBYEqY3O1RmQv9DE+PS+thi3X49yWsIOPn+of53hAZ555rODrfUbzrfj1K8i2WKrta BtH5RUyskzWX7SsZ1/d9cFa3gAq8ipsXwvzIIFYYJikHsZ0RXOu3mgi7QsmCgXwhc+KdPJdRUFDSM abwRJIoypYIb1XVEFwAN9eFS2jCBCPDCfdhQ7gZ0lMaUABiyUFyQdLzrUkfOoPJB570atGKrEzFzw eZmdRwxA==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.99 #2 (Red Hat Linux)) id 1vY6Xg-00000006R8R-0U3k; Tue, 23 Dec 2025 17:51:28 +0000 Date: Tue, 23 Dec 2025 17:51:28 +0000 From: Al Viro To: Andrei Topala Cc: Christian Brauner , Jan Kara , linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] fs: allow rename across bind mounts on same superblock Message-ID: <20251223175128.GC1712166@ZenIV> References: <20251223173803.1623903-1-topala.andrei@gmail.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251223173803.1623903-1-topala.andrei@gmail.com> Sender: Al Viro On Tue, Dec 23, 2025 at 05:38:03PM +0000, Andrei Topala wrote: > Currently rename() returns EXDEV when source and destination are on > different mounts, even if they're bind mounts of the same filesystem. > This forces userspace (mv) to fall back to slow copy+delete. > > Change the check from comparing mount pointers to comparing superblocks, > which allows renaming across bind mounts within the same filesystem. ... which destroys the use of bind mount as rename boundary. Why is that a good idea?