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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 A7A2DC35674 for ; Sun, 23 Feb 2020 15:04:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 881E0206ED for ; Sun, 23 Feb 2020 15:04:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727072AbgBWPEz (ORCPT ); Sun, 23 Feb 2020 10:04:55 -0500 Received: from mga12.intel.com ([192.55.52.136]:40581 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726208AbgBWPEz (ORCPT ); Sun, 23 Feb 2020 10:04:55 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 23 Feb 2020 07:04:54 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,476,1574150400"; d="scan'208";a="435670098" Received: from iweiny-desk2.sc.intel.com ([10.3.52.157]) by fmsmga005.fm.intel.com with ESMTP; 23 Feb 2020 07:04:54 -0800 Date: Sun, 23 Feb 2020 07:04:54 -0800 From: Ira Weiny To: "Darrick J. Wong" Cc: linux-kernel@vger.kernel.org, Alexander Viro , Dan Williams , Dave Chinner , Christoph Hellwig , "Theodore Y. Ts'o" , Jan Kara , linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH V4 09/13] fs/xfs: Add write aops lock to xfs layer Message-ID: <20200223150454.GD29607@iweiny-DESK2.sc.intel.com> References: <20200221004134.30599-1-ira.weiny@intel.com> <20200221004134.30599-10-ira.weiny@intel.com> <20200222003109.GE9506@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200222003109.GE9506@magnolia> User-Agent: Mutt/1.11.1 (2018-12-01) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri, Feb 21, 2020 at 04:31:09PM -0800, Darrick J. Wong wrote: > On Thu, Feb 20, 2020 at 04:41:30PM -0800, ira.weiny@intel.com wrote: > > From: Ira Weiny > > > > XFS requires the use of the aops of an inode to quiesced prior to > > changing it to/from the DAX aops vector. > > > > Take the aops write lock while changing DAX state. > > > > We define a new XFS_DAX_EXCL lock type to carry the lock through to > > transaction completion. > > > > Signed-off-by: Ira Weiny > > > > --- > > Changes from v3: > > Change locking function names to reflect changes in previous > > patches. > > > > Changes from V2: > > Change name of patch (WAS: fs/xfs: Add lock/unlock state to xfs) > > Remove the xfs specific lock and move to the vfs layer. > > We still use XFS_LOCK_DAX_EXCL to be able to pass this > > flag through to the transaction code. But we no longer > > have a lock specific to xfs. This removes a lot of code > > from the XFS layer, preps us for using this in ext4, and > > is actually more straight forward now that all the > > locking requirements are better known. > > > > Fix locking order comment > > Rework for new 'state' names > > (Other comments on the previous patch are not applicable with > > new patch as much of the code was removed in favor of the vfs > > level lock) > > --- > > fs/xfs/xfs_inode.c | 22 ++++++++++++++++++++-- > > fs/xfs/xfs_inode.h | 7 +++++-- > > 2 files changed, 25 insertions(+), 4 deletions(-) > > > > diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c > > index 35df324875db..5b014c428f0f 100644 > > --- a/fs/xfs/xfs_inode.c > > +++ b/fs/xfs/xfs_inode.c > > @@ -142,12 +142,12 @@ xfs_ilock_attr_map_shared( > > * > > * Basic locking order: > > * > > - * i_rwsem -> i_mmap_lock -> page_lock -> i_ilock > > + * s_dax_sem -> i_rwsem -> i_mmap_lock -> page_lock -> i_ilock > > "dax_sem"? I thought this was now called i_aops_sem? :-/ yep... > > > * > > * mmap_sem locking order: > > * > > * i_rwsem -> page lock -> mmap_sem > > - * mmap_sem -> i_mmap_lock -> page_lock > > + * s_dax_sem -> mmap_sem -> i_mmap_lock -> page_lock > > * > > * The difference in mmap_sem locking order mean that we cannot hold the > > * i_mmap_lock over syscall based read(2)/write(2) based IO. These IO paths can > > @@ -182,6 +182,9 @@ xfs_ilock( > > (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)); > > ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_SUBCLASS_MASK)) == 0); > > > > + if (lock_flags & XFS_DAX_EXCL) > > And similarly, I think this should be XFS_OPSLOCK_EXCL... ... and ... yes... Thanks for the review, I'll clean it up. Ira > > --D > > > + inode_aops_down_write(VFS_I(ip)); > > + > > if (lock_flags & XFS_IOLOCK_EXCL) { > > down_write_nested(&VFS_I(ip)->i_rwsem, > > XFS_IOLOCK_DEP(lock_flags)); > > @@ -224,6 +227,8 @@ xfs_ilock_nowait( > > * You can't set both SHARED and EXCL for the same lock, > > * and only XFS_IOLOCK_SHARED, XFS_IOLOCK_EXCL, XFS_ILOCK_SHARED, > > * and XFS_ILOCK_EXCL are valid values to set in lock_flags. > > + * > > + * XFS_DAX_* is not allowed > > */ > > ASSERT((lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) != > > (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)); > > @@ -232,6 +237,7 @@ xfs_ilock_nowait( > > ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) != > > (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)); > > ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_SUBCLASS_MASK)) == 0); > > + ASSERT((lock_flags & XFS_DAX_EXCL) == 0); > > > > if (lock_flags & XFS_IOLOCK_EXCL) { > > if (!down_write_trylock(&VFS_I(ip)->i_rwsem)) > > @@ -318,6 +324,9 @@ xfs_iunlock( > > else if (lock_flags & XFS_ILOCK_SHARED) > > mrunlock_shared(&ip->i_lock); > > > > + if (lock_flags & XFS_DAX_EXCL) > > + inode_aops_up_write(VFS_I(ip)); > > + > > trace_xfs_iunlock(ip, lock_flags, _RET_IP_); > > } > > > > @@ -333,6 +342,8 @@ xfs_ilock_demote( > > ASSERT(lock_flags & (XFS_IOLOCK_EXCL|XFS_MMAPLOCK_EXCL|XFS_ILOCK_EXCL)); > > ASSERT((lock_flags & > > ~(XFS_IOLOCK_EXCL|XFS_MMAPLOCK_EXCL|XFS_ILOCK_EXCL)) == 0); > > + /* XFS_DAX_* is not allowed */ > > + ASSERT((lock_flags & XFS_DAX_EXCL) == 0); > > > > if (lock_flags & XFS_ILOCK_EXCL) > > mrdemote(&ip->i_lock); > > @@ -465,6 +476,9 @@ xfs_lock_inodes( > > ASSERT(!(lock_mode & XFS_ILOCK_EXCL) || > > inodes <= XFS_ILOCK_MAX_SUBCLASS + 1); > > > > + /* XFS_DAX_* is not allowed */ > > + ASSERT((lock_mode & XFS_DAX_EXCL) == 0); > > + > > if (lock_mode & XFS_IOLOCK_EXCL) { > > ASSERT(!(lock_mode & (XFS_MMAPLOCK_EXCL | XFS_ILOCK_EXCL))); > > } else if (lock_mode & XFS_MMAPLOCK_EXCL) > > @@ -566,6 +580,10 @@ xfs_lock_two_inodes( > > ASSERT(!(ip0_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)) || > > !(ip1_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL))); > > > > + /* XFS_DAX_* is not allowed */ > > + ASSERT((ip0_mode & XFS_DAX_EXCL) == 0); > > + ASSERT((ip1_mode & XFS_DAX_EXCL) == 0); > > + > > ASSERT(ip0->i_ino != ip1->i_ino); > > > > if (ip0->i_ino > ip1->i_ino) { > > diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h > > index 492e53992fa9..25fe20740bf7 100644 > > --- a/fs/xfs/xfs_inode.h > > +++ b/fs/xfs/xfs_inode.h > > @@ -278,10 +278,12 @@ static inline void xfs_ifunlock(struct xfs_inode *ip) > > #define XFS_ILOCK_SHARED (1<<3) > > #define XFS_MMAPLOCK_EXCL (1<<4) > > #define XFS_MMAPLOCK_SHARED (1<<5) > > +#define XFS_DAX_EXCL (1<<6) > > > > #define XFS_LOCK_MASK (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED \ > > | XFS_ILOCK_EXCL | XFS_ILOCK_SHARED \ > > - | XFS_MMAPLOCK_EXCL | XFS_MMAPLOCK_SHARED) > > + | XFS_MMAPLOCK_EXCL | XFS_MMAPLOCK_SHARED \ > > + | XFS_DAX_EXCL) > > > > #define XFS_LOCK_FLAGS \ > > { XFS_IOLOCK_EXCL, "IOLOCK_EXCL" }, \ > > @@ -289,7 +291,8 @@ static inline void xfs_ifunlock(struct xfs_inode *ip) > > { XFS_ILOCK_EXCL, "ILOCK_EXCL" }, \ > > { XFS_ILOCK_SHARED, "ILOCK_SHARED" }, \ > > { XFS_MMAPLOCK_EXCL, "MMAPLOCK_EXCL" }, \ > > - { XFS_MMAPLOCK_SHARED, "MMAPLOCK_SHARED" } > > + { XFS_MMAPLOCK_SHARED, "MMAPLOCK_SHARED" }, \ > > + { XFS_DAX_EXCL, "DAX_EXCL" } > > > > > > /* > > -- > > 2.21.0 > >