From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from zinan.dashjr.org ([192.3.11.21]:47420 "EHLO zinan.dashjr.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932775AbbENQ17 (ORCPT ); Thu, 14 May 2015 12:27:59 -0400 From: Luke Dashjr To: dsterba@suse.cz Subject: Re: [PATCH] btrfs: bugfix: handle FS_IOC32_{GETFLAGS,SETFLAGS,GETVERSION} in btrfs_ioctl Date: Thu, 14 May 2015 16:27:54 +0000 Cc: Chris Mason , Josef Bacik , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, trivial@kernel.org References: <201505131715.27483.luke@dashjr.org> <20150514140617.GY23255@twin.jikos.cz> In-Reply-To: <20150514140617.GY23255@twin.jikos.cz> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Message-Id: <201505141627.56205.luke@dashjr.org> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Thursday, May 14, 2015 2:06:17 PM David Sterba wrote: > On Wed, May 13, 2015 at 05:15:26PM +0000, Luke Dashjr wrote: > > 32-bit ioctl uses these rather than the regular FS_IOC_* versions. They > > can be handled in btrfs using the same code. Without this, 32-bit > > {ch,ls}attr fail. > > Yes, but this has to be implemented in another way. See eg. > https://git.kernel.org/linus/e9750824114ff I don't see what is different with that implementation. All f2fs_compat_ioctl does is change cmd to the plain-IOC equivalent and call f2fs_ioctl with the same arg (compat_ptr merely causes a cast to void* and back, which AFAIK is a noop on 64-bit?). Am I missing something? I could try to just imitate it, but I'd rather know what is significant/going on to ensure I don't waste your time with code I don't even properly understand myself. Perhaps by coincidence, the patch does at least in practice work (although at least `btrfs send` appears to be broken still, and I'm at a loss for how to approach fixing that). Luke