From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D333BC4345F for ; Thu, 18 Apr 2024 07:49:36 +0000 (UTC) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=uuWjR6cA; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4VKqg3358gz3cXF for ; Thu, 18 Apr 2024 17:49:35 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=uuWjR6cA; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=145.40.73.55; helo=sin.source.kernel.org; envelope-from=xiang@kernel.org; receiver=lists.ozlabs.org) Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4VKqfv4v3rz3cQq for ; Thu, 18 Apr 2024 17:49:27 +1000 (AEST) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id 87F24CE174E; Thu, 18 Apr 2024 07:49:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7DD70C113CC; Thu, 18 Apr 2024 07:49:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1713426563; bh=tOG2QuI93DOp+bJmmh7Zv4ScyQbFEf3WUpu5J3kJgB4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=uuWjR6cAbT8LcS5lff1QDoZC0Ukf9nBlj4mip5mHsTLHK2j25/bWNM6431AzE9ibF Ovz8qVbXyw6t7TlFv/fVQP2gjEbp+z/+TWbgO1p24c1wpXUt0rpd/nkrmGoWvZDWVg yR2C68ee7ejaQl7qg9PGHkur6zfg6dgTWKDm0zJ8yCAhMzx4B2wGZel06VuE9Jq8hL 9bxrcGqnihH/TDu29vqW9mVtXLh5H5d/mr3D9In9S1OX933jTwErWPX2+knEw+g1Vp l9caeyllnKGDx9LXGHMToilBAtveSxRUZfgtOQRpGLn+G/tdKFCPeglJIZuSeRfLXM cpkoks1YgxRsQ== Date: Thu, 18 Apr 2024 15:49:22 +0800 From: Gao Xiang To: Baokun Li Subject: Re: [PATCH v2] erofs: reliably distinguish block based and fscache mode Message-ID: Mail-Followup-To: Baokun Li , Jingbo Xu , linux-erofs@lists.ozlabs.org, xiang@kernel.org, chao@kernel.org, huyue2@coolpad.com, viro@zeniv.linux.org.uk, brauner@kernel.org, linux-kernel@vger.kernel.org, yangerkun@huawei.com, houtao1@huawei.com References: <20240417065513.3409744-1-libaokun1@huawei.com> <71e66b02-9c2b-4981-83e1-8af72d6c0975@linux.alibaba.com> <7fdf4bff-2d3d-bdc0-5446-caa58aeca314@huawei.com> <48b21671-19ae-0dbd-96cd-7300fd600c9b@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <48b21671-19ae-0dbd-96cd-7300fd600c9b@huawei.com> X-BeenThere: linux-erofs@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development of Linux EROFS file system List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: brauner@kernel.org, yangerkun@huawei.com, linux-kernel@vger.kernel.org, huyue2@coolpad.com, viro@zeniv.linux.org.uk, linux-erofs@lists.ozlabs.org Errors-To: linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Sender: "Linux-erofs" Hi, On Thu, Apr 18, 2024 at 02:12:39PM +0800, Baokun Li wrote: > On 2024/4/18 13:50, Jingbo Xu wrote: > > > > On 4/18/24 11:36 AM, Baokun Li wrote: > > > On 2024/4/18 10:16, Jingbo Xu wrote: > > > > Hi Baokun, > > > > > > > > Thanks for catching this and move forward fixing this! > > > Hi Jingbo， > > > > > > Thanks for your review！ > > > > > > > On 4/17/24 2:55 PM, Baokun Li wrote: > > > > > When erofs_kill_sb() is called in block dev based mode, s_bdev may > > > > > not have > > > > > been initialised yet, and if CONFIG_EROFS_FS_ONDEMAND is enabled, it > > > > > will > > > > > be mistaken for fscache mode, and then attempt to free an anon_dev > > > > > that has > > > > > never been allocated, triggering the following warning: > > > > > > > > > > ============================================ > > > > > ida_free called for id=0 which is not allocated. > > > > > WARNING: CPU: 14 PID: 926 at lib/idr.c:525 ida_free+0x134/0x140 > > > > > Modules linked in: > > > > > CPU: 14 PID: 926 Comm: mount Not tainted 6.9.0-rc3-dirty #630 > > > > > RIP: 0010:ida_free+0x134/0x140 > > > > > Call Trace: > > > > >   > > > > >   erofs_kill_sb+0x81/0x90 > > > > >   deactivate_locked_super+0x35/0x80 > > > > >   get_tree_bdev+0x136/0x1e0 > > > > >   vfs_get_tree+0x2c/0xf0 > > > > >   do_new_mount+0x190/0x2f0 > > > > >   [...] > > > > > ============================================ > > > > > > > > > > Instead of allocating the erofs_sb_info in fill_super() allocate it > > > > > during erofs_get_tree() and ensure that erofs can always have the info > > > > > available during erofs_kill_sb(). > > > > I'm not sure if allocating erofs_sb_info in erofs_init_fs_context() will > > > > be better, as I see some filesystems (e.g. autofs) do this way.  Maybe > > > > another potential advantage of doing this way is that erofs_fs_context > > > > is not needed anymore and we can use sbi directly. > > > Yes, except for some extra memory usage when remounting, > > > this idea sounds great. Let me send a version of v3 to get rid > > > of erofs_fs_context. > > I'm not sure if Gao Xaing also prefers this. I think it would be better > > to wait and listen for his thoughts before we sending v3. >  Okay, there's no rush on this. I checked days ago, for example, XFS is also worked in this way. And .reconfigure() needs to be carefully handled too. > > > > > Signed-off-by: Christian Brauner > > > > > Signed-off-by: Baokun Li > > > > > --- > > > > > Changes since v1: > > > > >    Allocate and initialise fc->s_fs_info in erofs_fc_get_tree() > > > > > instead of > > > > >    modifying fc->sb_flags. > > > > > > > > > > V1: > > > > > https://lore.kernel.org/r/20240415121746.1207242-1-libaokun1@huawei.com/ > > > > > > > > > >   fs/erofs/super.c | 51 ++++++++++++++++++++++++++---------------------- > > > > >   1 file changed, 28 insertions(+), 23 deletions(-) > > > > > > > > > > diff --git a/fs/erofs/super.c b/fs/erofs/super.c > > > > > index b21bd8f78dc1..4104280be2ea 100644 > > > > > --- a/fs/erofs/super.c > > > > > +++ b/fs/erofs/super.c > > > > > @@ -581,8 +581,7 @@ static const struct export_operations > > > > > erofs_export_ops = { > > > > >   static int erofs_fc_fill_super(struct super_block *sb, struct > > > > > fs_context *fc) > > > > >   { > > > > >       struct inode *inode; > > > > > -    struct erofs_sb_info *sbi; > > > > > -    struct erofs_fs_context *ctx = fc->fs_private; > > > > > +    struct erofs_sb_info *sbi = EROFS_SB(sb); > > > > >       int err; > > > > >         sb->s_magic = EROFS_SUPER_MAGIC; > > > > > @@ -590,19 +589,6 @@ static int erofs_fc_fill_super(struct > > > > > super_block *sb, struct fs_context *fc) > > > > >       sb->s_maxbytes = MAX_LFS_FILESIZE; > > > > >       sb->s_op = &erofs_sops; > > > > >   -    sbi = kzalloc(sizeof(*sbi), GFP_KERNEL); > > > > > -    if (!sbi) > > > > > -        return -ENOMEM; > > > > > - > > > > > -    sb->s_fs_info = sbi; > > > > > -    sbi->opt = ctx->opt; > > > > > -    sbi->devs = ctx->devs; > > > > > -    ctx->devs = NULL; > > > > > -    sbi->fsid = ctx->fsid; > > > > > -    ctx->fsid = NULL; > > > > > -    sbi->domain_id = ctx->domain_id; > > > > > -    ctx->domain_id = NULL; > > > > > - > > > > >       sbi->blkszbits = PAGE_SHIFT; > > > > >       if (erofs_is_fscache_mode(sb)) { > > > > >           sb->s_blocksize = PAGE_SIZE; > > > > > @@ -704,11 +690,32 @@ static int erofs_fc_fill_super(struct > > > > > super_block *sb, struct fs_context *fc) > > > > >       return 0; > > > > >   } > > > > >   -static int erofs_fc_get_tree(struct fs_context *fc) > > > > > +static void erofs_ctx_to_info(struct fs_context *fc) > > > > >   { > > > > >       struct erofs_fs_context *ctx = fc->fs_private; > > > > > +    struct erofs_sb_info *sbi = fc->s_fs_info; > > > > > + > > > > > +    sbi->opt = ctx->opt; > > > > > +    sbi->devs = ctx->devs; > > > > > +    ctx->devs = NULL; > > > > > +    sbi->fsid = ctx->fsid; > > > > > +    ctx->fsid = NULL; > > > > > +    sbi->domain_id = ctx->domain_id; > > > > > +    ctx->domain_id = NULL; > > > > > +} > > > > I'm not sure if abstracting this logic into a seperate helper really > > > > helps understanding the code as the logic itself is quite simple and > > > > easy to be understood. Usually it's a hint of over-abstraction when a > > > > simple helper has only one caller. > > > > > > > Static functions that have only one caller are compiled inline, so we > > > don't have to worry about how that affects the code. > > > > > > The reason these codes are encapsulated in a separate function is so > > > that the code reader understands that these codes are integrated > > > as a whole, and that we shouldn't have to move one or two of these > > > lines individually. > > > > > > But after we get rid of erofs_fs_context, those won't be needed > > > anymore. > > Yeah, I understand. It's only coding style concerns. > > > > > > > Okay, thanks！ I'm fine to get rid of those (erofs_fs_context) as long as the codebase is more clearer and simple. BTW, for the current codebase, I also think it's unneeded to have a separate helper called once without extra actual meaning... Thanks, Gao Xiang > > -- > With Best Regards, > Baokun Li From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 36E053B79F for ; Thu, 18 Apr 2024 07:49:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713426564; cv=none; b=ZCs5JyvHv1br7aKnHpXuiJLO6aqb0pYb8NvGHL1y3L/f0z+tFTjl0SJYdkmriKkXHciUW8eyMnUsP8OUhxoI48DFgU3qkUqGZbECPgNAXIuzfk/MCgIYCDvqUjtgB2r8oePlCui0d2MIGUFyS99E8qWFx2Wv5n5iTxLUBRmHj1w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713426564; c=relaxed/simple; bh=tOG2QuI93DOp+bJmmh7Zv4ScyQbFEf3WUpu5J3kJgB4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kiC6mM/pGjYP2i3ScXaxWL9gb8agTMiiwY/xG24psXqWHJDLAdHGv0K9hchFpRPHVIYXMdN78qOOVdv+JXWlaYgqJrxOWzHLl420G9hhzb7uXEid/xZjJzvzWPGgQCO2G7qa+AZvFqri/XvsULwk8hCuATnqLh8NdxoRD7W9RVQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=uuWjR6cA; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="uuWjR6cA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7DD70C113CC; Thu, 18 Apr 2024 07:49:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1713426563; bh=tOG2QuI93DOp+bJmmh7Zv4ScyQbFEf3WUpu5J3kJgB4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=uuWjR6cAbT8LcS5lff1QDoZC0Ukf9nBlj4mip5mHsTLHK2j25/bWNM6431AzE9ibF Ovz8qVbXyw6t7TlFv/fVQP2gjEbp+z/+TWbgO1p24c1wpXUt0rpd/nkrmGoWvZDWVg yR2C68ee7ejaQl7qg9PGHkur6zfg6dgTWKDm0zJ8yCAhMzx4B2wGZel06VuE9Jq8hL 9bxrcGqnihH/TDu29vqW9mVtXLh5H5d/mr3D9In9S1OX933jTwErWPX2+knEw+g1Vp l9caeyllnKGDx9LXGHMToilBAtveSxRUZfgtOQRpGLn+G/tdKFCPeglJIZuSeRfLXM cpkoks1YgxRsQ== Date: Thu, 18 Apr 2024 15:49:22 +0800 From: Gao Xiang To: Baokun Li Cc: Jingbo Xu , linux-erofs@lists.ozlabs.org, xiang@kernel.org, chao@kernel.org, huyue2@coolpad.com, viro@zeniv.linux.org.uk, brauner@kernel.org, linux-kernel@vger.kernel.org, yangerkun@huawei.com, houtao1@huawei.com Subject: Re: [PATCH v2] erofs: reliably distinguish block based and fscache mode Message-ID: Mail-Followup-To: Baokun Li , Jingbo Xu , linux-erofs@lists.ozlabs.org, xiang@kernel.org, chao@kernel.org, huyue2@coolpad.com, viro@zeniv.linux.org.uk, brauner@kernel.org, linux-kernel@vger.kernel.org, yangerkun@huawei.com, houtao1@huawei.com References: <20240417065513.3409744-1-libaokun1@huawei.com> <71e66b02-9c2b-4981-83e1-8af72d6c0975@linux.alibaba.com> <7fdf4bff-2d3d-bdc0-5446-caa58aeca314@huawei.com> <48b21671-19ae-0dbd-96cd-7300fd600c9b@huawei.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <48b21671-19ae-0dbd-96cd-7300fd600c9b@huawei.com> Hi, On Thu, Apr 18, 2024 at 02:12:39PM +0800, Baokun Li wrote: > On 2024/4/18 13:50, Jingbo Xu wrote: > > > > On 4/18/24 11:36 AM, Baokun Li wrote: > > > On 2024/4/18 10:16, Jingbo Xu wrote: > > > > Hi Baokun, > > > > > > > > Thanks for catching this and move forward fixing this! > > > Hi Jingbo， > > > > > > Thanks for your review！ > > > > > > > On 4/17/24 2:55 PM, Baokun Li wrote: > > > > > When erofs_kill_sb() is called in block dev based mode, s_bdev may > > > > > not have > > > > > been initialised yet, and if CONFIG_EROFS_FS_ONDEMAND is enabled, it > > > > > will > > > > > be mistaken for fscache mode, and then attempt to free an anon_dev > > > > > that has > > > > > never been allocated, triggering the following warning: > > > > > > > > > > ============================================ > > > > > ida_free called for id=0 which is not allocated. > > > > > WARNING: CPU: 14 PID: 926 at lib/idr.c:525 ida_free+0x134/0x140 > > > > > Modules linked in: > > > > > CPU: 14 PID: 926 Comm: mount Not tainted 6.9.0-rc3-dirty #630 > > > > > RIP: 0010:ida_free+0x134/0x140 > > > > > Call Trace: > > > > >   > > > > >   erofs_kill_sb+0x81/0x90 > > > > >   deactivate_locked_super+0x35/0x80 > > > > >   get_tree_bdev+0x136/0x1e0 > > > > >   vfs_get_tree+0x2c/0xf0 > > > > >   do_new_mount+0x190/0x2f0 > > > > >   [...] > > > > > ============================================ > > > > > > > > > > Instead of allocating the erofs_sb_info in fill_super() allocate it > > > > > during erofs_get_tree() and ensure that erofs can always have the info > > > > > available during erofs_kill_sb(). > > > > I'm not sure if allocating erofs_sb_info in erofs_init_fs_context() will > > > > be better, as I see some filesystems (e.g. autofs) do this way.  Maybe > > > > another potential advantage of doing this way is that erofs_fs_context > > > > is not needed anymore and we can use sbi directly. > > > Yes, except for some extra memory usage when remounting, > > > this idea sounds great. Let me send a version of v3 to get rid > > > of erofs_fs_context. > > I'm not sure if Gao Xaing also prefers this. I think it would be better > > to wait and listen for his thoughts before we sending v3. >  Okay, there's no rush on this. I checked days ago, for example, XFS is also worked in this way. And .reconfigure() needs to be carefully handled too. > > > > > Signed-off-by: Christian Brauner > > > > > Signed-off-by: Baokun Li > > > > > --- > > > > > Changes since v1: > > > > >    Allocate and initialise fc->s_fs_info in erofs_fc_get_tree() > > > > > instead of > > > > >    modifying fc->sb_flags. > > > > > > > > > > V1: > > > > > https://lore.kernel.org/r/20240415121746.1207242-1-libaokun1@huawei.com/ > > > > > > > > > >   fs/erofs/super.c | 51 ++++++++++++++++++++++++++---------------------- > > > > >   1 file changed, 28 insertions(+), 23 deletions(-) > > > > > > > > > > diff --git a/fs/erofs/super.c b/fs/erofs/super.c > > > > > index b21bd8f78dc1..4104280be2ea 100644 > > > > > --- a/fs/erofs/super.c > > > > > +++ b/fs/erofs/super.c > > > > > @@ -581,8 +581,7 @@ static const struct export_operations > > > > > erofs_export_ops = { > > > > >   static int erofs_fc_fill_super(struct super_block *sb, struct > > > > > fs_context *fc) > > > > >   { > > > > >       struct inode *inode; > > > > > -    struct erofs_sb_info *sbi; > > > > > -    struct erofs_fs_context *ctx = fc->fs_private; > > > > > +    struct erofs_sb_info *sbi = EROFS_SB(sb); > > > > >       int err; > > > > >         sb->s_magic = EROFS_SUPER_MAGIC; > > > > > @@ -590,19 +589,6 @@ static int erofs_fc_fill_super(struct > > > > > super_block *sb, struct fs_context *fc) > > > > >       sb->s_maxbytes = MAX_LFS_FILESIZE; > > > > >       sb->s_op = &erofs_sops; > > > > >   -    sbi = kzalloc(sizeof(*sbi), GFP_KERNEL); > > > > > -    if (!sbi) > > > > > -        return -ENOMEM; > > > > > - > > > > > -    sb->s_fs_info = sbi; > > > > > -    sbi->opt = ctx->opt; > > > > > -    sbi->devs = ctx->devs; > > > > > -    ctx->devs = NULL; > > > > > -    sbi->fsid = ctx->fsid; > > > > > -    ctx->fsid = NULL; > > > > > -    sbi->domain_id = ctx->domain_id; > > > > > -    ctx->domain_id = NULL; > > > > > - > > > > >       sbi->blkszbits = PAGE_SHIFT; > > > > >       if (erofs_is_fscache_mode(sb)) { > > > > >           sb->s_blocksize = PAGE_SIZE; > > > > > @@ -704,11 +690,32 @@ static int erofs_fc_fill_super(struct > > > > > super_block *sb, struct fs_context *fc) > > > > >       return 0; > > > > >   } > > > > >   -static int erofs_fc_get_tree(struct fs_context *fc) > > > > > +static void erofs_ctx_to_info(struct fs_context *fc) > > > > >   { > > > > >       struct erofs_fs_context *ctx = fc->fs_private; > > > > > +    struct erofs_sb_info *sbi = fc->s_fs_info; > > > > > + > > > > > +    sbi->opt = ctx->opt; > > > > > +    sbi->devs = ctx->devs; > > > > > +    ctx->devs = NULL; > > > > > +    sbi->fsid = ctx->fsid; > > > > > +    ctx->fsid = NULL; > > > > > +    sbi->domain_id = ctx->domain_id; > > > > > +    ctx->domain_id = NULL; > > > > > +} > > > > I'm not sure if abstracting this logic into a seperate helper really > > > > helps understanding the code as the logic itself is quite simple and > > > > easy to be understood. Usually it's a hint of over-abstraction when a > > > > simple helper has only one caller. > > > > > > > Static functions that have only one caller are compiled inline, so we > > > don't have to worry about how that affects the code. > > > > > > The reason these codes are encapsulated in a separate function is so > > > that the code reader understands that these codes are integrated > > > as a whole, and that we shouldn't have to move one or two of these > > > lines individually. > > > > > > But after we get rid of erofs_fs_context, those won't be needed > > > anymore. > > Yeah, I understand. It's only coding style concerns. > > > > > > > Okay, thanks！ I'm fine to get rid of those (erofs_fs_context) as long as the codebase is more clearer and simple. BTW, for the current codebase, I also think it's unneeded to have a separate helper called once without extra actual meaning... Thanks, Gao Xiang > > -- > With Best Regards, > Baokun Li