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 X-Spam-Level: X-Spam-Status: No, score=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 395DDC47082 for ; Wed, 26 May 2021 13:42:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 18B41613C9 for ; Wed, 26 May 2021 13:42:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234225AbhEZNoI (ORCPT ); Wed, 26 May 2021 09:44:08 -0400 Received: from mx2.suse.de ([195.135.220.15]:50700 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233906AbhEZNoH (ORCPT ); Wed, 26 May 2021 09:44:07 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1622036554; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=YWrDO/Dppqnob0qSTudrbGU+4KXNmLknkAXHAtjqkPI=; b=feNDsCEwezBY5eajE0X9sqDHnTCioCQIzIeMr2J2TrAYh7OvQMpRR6ljQ64+nCIR6LMdDE Zi5dHF8941OXqyI8echxk8PnDv2x3Co9ptmb0tEfZbrdSAZ51qfP8Op/Pijg7rG4X5h5X8 Br72v5QvgRMXQv/fSVf4n4nH4GugQI8= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1622036554; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=YWrDO/Dppqnob0qSTudrbGU+4KXNmLknkAXHAtjqkPI=; b=pwgOPKA3405jgMM+/qCsJ5+JNbyatYjdP7zr8GOt7RfHlu5t01djSVRCJw4CaQDbGc+iFj eBqVo0DURM5CFSDA== Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id EE6B0AEE7; Wed, 26 May 2021 13:42:33 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 696871F2CAC; Wed, 26 May 2021 15:42:32 +0200 (CEST) Date: Wed, 26 May 2021 15:42:32 +0200 From: Jan Kara To: Dave Chinner Cc: Jan Kara , linux-fsdevel@vger.kernel.org, Christoph Hellwig , ceph-devel@vger.kernel.org, Chao Yu , Damien Le Moal , "Darrick J. Wong" , Jaegeuk Kim , Jeff Layton , Johannes Thumshirn , linux-cifs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-mm@kvack.org, linux-xfs@vger.kernel.org, Miklos Szeredi , Steve French , Ted Tso , Matthew Wilcox , Christoph Hellwig Subject: Re: [PATCH 07/13] xfs: Convert to use invalidate_lock Message-ID: <20210526134232.GE30369@quack2.suse.cz> References: <20210525125652.20457-1-jack@suse.cz> <20210525135100.11221-7-jack@suse.cz> <20210525214041.GJ664593@dread.disaster.area> <20210526102059.GD30369@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210526102059.GD30369@quack2.suse.cz> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org On Wed 26-05-21 12:20:59, Jan Kara wrote: > On Wed 26-05-21 07:40:41, Dave Chinner wrote: > > On Tue, May 25, 2021 at 03:50:44PM +0200, Jan Kara wrote: > > > Use invalidate_lock instead of XFS internal i_mmap_lock. The intended > > > purpose of invalidate_lock is exactly the same. Note that the locking in > > > __xfs_filemap_fault() slightly changes as filemap_fault() already takes > > > invalidate_lock. > > > > > > Reviewed-by: Christoph Hellwig > > > CC: > > > CC: "Darrick J. Wong" > > > Signed-off-by: Jan Kara > > > --- > > > fs/xfs/xfs_file.c | 12 ++++++----- > > > fs/xfs/xfs_inode.c | 52 ++++++++++++++++++++++++++-------------------- > > > fs/xfs/xfs_inode.h | 1 - > > > fs/xfs/xfs_super.c | 2 -- > > > 4 files changed, 36 insertions(+), 31 deletions(-) > > > > > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c > > > index 396ef36dcd0a..dc9cb5c20549 100644 > > > --- a/fs/xfs/xfs_file.c > > > +++ b/fs/xfs/xfs_file.c > > > @@ -1282,7 +1282,7 @@ xfs_file_llseek( > > > * > > > * mmap_lock (MM) > > > * sb_start_pagefault(vfs, freeze) > > > - * i_mmaplock (XFS - truncate serialisation) > > > + * invalidate_lock (vfs/XFS_MMAPLOCK - truncate serialisation) > > > * page_lock (MM) > > > * i_lock (XFS - extent map serialisation) > > > */ > > > @@ -1303,24 +1303,26 @@ __xfs_filemap_fault( > > > file_update_time(vmf->vma->vm_file); > > > } > > > > > > - xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED); > > > if (IS_DAX(inode)) { > > > pfn_t pfn; > > > > > > + xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED); > > > ret = dax_iomap_fault(vmf, pe_size, &pfn, NULL, > > > (write_fault && !vmf->cow_page) ? > > > &xfs_direct_write_iomap_ops : > > > &xfs_read_iomap_ops); > > > if (ret & VM_FAULT_NEEDDSYNC) > > > ret = dax_finish_sync_fault(vmf, pe_size, pfn); > > > + xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED); > > > } else { > > > - if (write_fault) > > > + if (write_fault) { > > > + xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED); > > > ret = iomap_page_mkwrite(vmf, > > > &xfs_buffered_write_iomap_ops); > > > - else > > > + xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED); > > > + } else > > > ret = filemap_fault(vmf); > > > } > > > - xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED); > > > > This seems kinda messy. filemap_fault() basically takes the > > invalidate lock around the entire operation, it runs, so maybe it > > would be cleaner to implement it as: > > > > filemap_fault_locked(vmf) > > { > > /* does the filemap fault work */ > > } > > > > filemap_fault(vmf) > > { > > filemap_invalidate_down_read(...) > > ret = filemap_fault_locked(vmf) > > filemap_invalidate_up_read(...) > > return ret; > > } > > > > And that means XFS could just call filemap_fault_locked() and not > > have to do all this messy locking just to avoid holding the lock > > that filemap_fault has now internalised. > > Sure, I can do that. Hum, looking into this in more detail it isn't as easy. There are some operations inside filemap_fault() that need to be done outside of invalidate_lock. In particular we call into readahead code which will grab invalidate_lock for itself. So we'd need to pass in struct readahead_control whether invalidate_lock is held or not which is IMHO uglier than what we currently do in __xfs_filemap_fault(). Honza -- Jan Kara SUSE Labs, CR 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 X-Spam-Level: X-Spam-Status: No, score=-15.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19CB9C47082 for ; Wed, 26 May 2021 13:42:45 +0000 (UTC) Received: from lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AC9D3613C9; Wed, 26 May 2021 13:42:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AC9D3613C9 Authentication-Results: mail.kernel.org; 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Wed, 26 May 2021 13:42:33 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 696871F2CAC; Wed, 26 May 2021 15:42:32 +0200 (CEST) Date: Wed, 26 May 2021 15:42:32 +0200 From: Jan Kara To: Dave Chinner Message-ID: <20210526134232.GE30369@quack2.suse.cz> References: <20210525125652.20457-1-jack@suse.cz> <20210525135100.11221-7-jack@suse.cz> <20210525214041.GJ664593@dread.disaster.area> <20210526102059.GD30369@quack2.suse.cz> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210526102059.GD30369@quack2.suse.cz> User-Agent: Mutt/1.10.1 (2018-07-13) X-Headers-End: 1llto0-006aWh-AU Subject: Re: [f2fs-dev] [PATCH 07/13] xfs: Convert to use invalidate_lock X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-cifs@vger.kernel.org, Damien Le Moal , linux-ext4@vger.kernel.org, Jan Kara , "Darrick J. Wong" , Steve French , Jeff Layton , Matthew Wilcox , linux-f2fs-devel@lists.sourceforge.net, Christoph Hellwig , linux-mm@kvack.org, Miklos Szeredi , Ted Tso , linux-fsdevel@vger.kernel.org, Jaegeuk Kim , ceph-devel@vger.kernel.org, Johannes Thumshirn , Christoph Hellwig , linux-xfs@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On Wed 26-05-21 12:20:59, Jan Kara wrote: > On Wed 26-05-21 07:40:41, Dave Chinner wrote: > > On Tue, May 25, 2021 at 03:50:44PM +0200, Jan Kara wrote: > > > Use invalidate_lock instead of XFS internal i_mmap_lock. The intended > > > purpose of invalidate_lock is exactly the same. Note that the locking in > > > __xfs_filemap_fault() slightly changes as filemap_fault() already takes > > > invalidate_lock. > > > > > > Reviewed-by: Christoph Hellwig > > > CC: > > > CC: "Darrick J. Wong" > > > Signed-off-by: Jan Kara > > > --- > > > fs/xfs/xfs_file.c | 12 ++++++----- > > > fs/xfs/xfs_inode.c | 52 ++++++++++++++++++++++++++-------------------- > > > fs/xfs/xfs_inode.h | 1 - > > > fs/xfs/xfs_super.c | 2 -- > > > 4 files changed, 36 insertions(+), 31 deletions(-) > > > > > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c > > > index 396ef36dcd0a..dc9cb5c20549 100644 > > > --- a/fs/xfs/xfs_file.c > > > +++ b/fs/xfs/xfs_file.c > > > @@ -1282,7 +1282,7 @@ xfs_file_llseek( > > > * > > > * mmap_lock (MM) > > > * sb_start_pagefault(vfs, freeze) > > > - * i_mmaplock (XFS - truncate serialisation) > > > + * invalidate_lock (vfs/XFS_MMAPLOCK - truncate serialisation) > > > * page_lock (MM) > > > * i_lock (XFS - extent map serialisation) > > > */ > > > @@ -1303,24 +1303,26 @@ __xfs_filemap_fault( > > > file_update_time(vmf->vma->vm_file); > > > } > > > > > > - xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED); > > > if (IS_DAX(inode)) { > > > pfn_t pfn; > > > > > > + xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED); > > > ret = dax_iomap_fault(vmf, pe_size, &pfn, NULL, > > > (write_fault && !vmf->cow_page) ? > > > &xfs_direct_write_iomap_ops : > > > &xfs_read_iomap_ops); > > > if (ret & VM_FAULT_NEEDDSYNC) > > > ret = dax_finish_sync_fault(vmf, pe_size, pfn); > > > + xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED); > > > } else { > > > - if (write_fault) > > > + if (write_fault) { > > > + xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED); > > > ret = iomap_page_mkwrite(vmf, > > > &xfs_buffered_write_iomap_ops); > > > - else > > > + xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED); > > > + } else > > > ret = filemap_fault(vmf); > > > } > > > - xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED); > > > > This seems kinda messy. filemap_fault() basically takes the > > invalidate lock around the entire operation, it runs, so maybe it > > would be cleaner to implement it as: > > > > filemap_fault_locked(vmf) > > { > > /* does the filemap fault work */ > > } > > > > filemap_fault(vmf) > > { > > filemap_invalidate_down_read(...) > > ret = filemap_fault_locked(vmf) > > filemap_invalidate_up_read(...) > > return ret; > > } > > > > And that means XFS could just call filemap_fault_locked() and not > > have to do all this messy locking just to avoid holding the lock > > that filemap_fault has now internalised. > > Sure, I can do that. Hum, looking into this in more detail it isn't as easy. There are some operations inside filemap_fault() that need to be done outside of invalidate_lock. In particular we call into readahead code which will grab invalidate_lock for itself. So we'd need to pass in struct readahead_control whether invalidate_lock is held or not which is IMHO uglier than what we currently do in __xfs_filemap_fault(). Honza -- Jan Kara SUSE Labs, CR _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel