From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from verein.lst.de ([213.95.11.211]:36437 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726405AbeIJMjG (ORCPT ); Mon, 10 Sep 2018 08:39:06 -0400 Date: Mon, 10 Sep 2018 09:50:39 +0200 From: Christoph Hellwig To: Carlos Maiolino Cc: Christoph Hellwig , Matthew Wilcox , linux-fsdevel@vger.kernel.org, sandeen@redhat.com, david@fromorbit.com Subject: Re: [PATCH 2/2] Use fiemap internal infra-structure to handle FIBMAP Message-ID: <20180910075039.GA14999@lst.de> References: <20180905135748.30098-1-cmaiolino@redhat.com> <20180905135748.30098-3-cmaiolino@redhat.com> <20180905143147.GC3729@bombadil.infradead.org> <20180905185649.GB423@lst.de> <20180906083105.tsqbpypdalekpaom@odin.usersys.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180906083105.tsqbpypdalekpaom@odin.usersys.redhat.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Thu, Sep 06, 2018 at 10:31:05AM +0200, Carlos Maiolino wrote: > > Sorry, I'm not 100% sure I followed your point here, do you mind to detail it a > bit? > Passing fiemap_fill_next_extent() as a pointer to what? ->fiemap() interface? Yes. > Sounds interesting, but doing this looks like I'll need to do what I was trying > to avoid from the beginning, which is the creating of a second struct > fiemap_extent_info, to be used in-lernel only, so, the last field doesn't need > to be tagged as __user. I'm ok with that though, I was just trying a way to > avoid adding unneeded data structures if possible, but looks like it ended up > not being a good approach :P fieinfo is mostly used as an opaqueue cookie, so I think it should be possible to just pass a void pointer to fiemap and only let the 'filler' callback (that is fiemap_fill_next_extent or whatever a kernel caller passed) interpret it. The only thing breaking this right now seems to be fi_flags, so maybe we just need to pass that explicitly as another argument to ->fiemap. Something like: typedef int (fiemap_fill_cb)(struct inode *inode, void *data, u64 logical, u64 phys, u64 len, u32 flags); struct file_operations { ... int (*fiemap)(struct inode *, unsigned int, fiemap_fill_cb, void *, u64 start, u64 len); ... };