From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (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 CDDAE3FC5 for ; Thu, 16 Sep 2021 00:30:09 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 491556108F; Thu, 16 Sep 2021 00:30:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631752209; bh=RTxTQggqSxSYdn2y3gMxq6FoxSHAqy63/h21L2l9IRg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=d+iusVMvz3jRSfTsKEk2750zrmp+bxGU83YcFVS3zgJJY5KNuTGrUus6hqAv7NRus xZfemHe3GZfd+wXGEqUFpr93ea9KMDDhMKnxH9pTnv0pFol/ghTqhYfDzKPcFsSf45 3IOB1ZGILT3odwkmYwsPu3Krw8H9nLaz7iWSQ/Vw/dgyK260mVocdG1x0f9b+YYbNB k5qPED0BYUc+bh98JIkb9OUgZUpJzqi01zisxEbENjTEaPzz/LrDz0rgteAzBNlVLX HtAAk57VS16JzM2BI/vl7SSWEaaH6y1EPxPP2KqqEzfOif1kxTsbWo2AyHcAPEwR9s otHt644RlBSDQ== Date: Wed, 15 Sep 2021 17:30:08 -0700 From: "Darrick J. Wong" To: Shiyang Ruan Cc: hch@lst.de, linux-xfs@vger.kernel.org, dan.j.williams@intel.com, david@fromorbit.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, nvdimm@lists.linux.dev, rgoldwyn@suse.de, viro@zeniv.linux.org.uk, willy@infradead.org Subject: Re: [PATCH v9 8/8] xfs: Add dax dedupe support Message-ID: <20210916003008.GE34830@magnolia> References: <20210915104501.4146910-1-ruansy.fnst@fujitsu.com> <20210915104501.4146910-9-ruansy.fnst@fujitsu.com> Precedence: bulk X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210915104501.4146910-9-ruansy.fnst@fujitsu.com> On Wed, Sep 15, 2021 at 06:45:01PM +0800, Shiyang Ruan wrote: > Introduce xfs_mmaplock_two_inodes_and_break_dax_layout() for dax files > who are going to be deduped. After that, call compare range function > only when files are both DAX or not. > > Signed-off-by: Shiyang Ruan > Reviewed-by: Darrick J. Wong > Reviewed-by: Christoph Hellwig > --- > fs/xfs/xfs_file.c | 2 +- > fs/xfs/xfs_inode.c | 80 +++++++++++++++++++++++++++++++++++++++++--- > fs/xfs/xfs_inode.h | 1 + > fs/xfs/xfs_reflink.c | 4 +-- > 4 files changed, 80 insertions(+), 7 deletions(-) > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c > index 2ef1930374d2..c3061723613c 100644 > --- a/fs/xfs/xfs_file.c > +++ b/fs/xfs/xfs_file.c > @@ -846,7 +846,7 @@ xfs_wait_dax_page( > xfs_ilock(ip, XFS_MMAPLOCK_EXCL); > } > > -static int > +int > xfs_break_dax_layouts( > struct inode *inode, > bool *retry) > diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c > index a4f6f034fb81..bdc084cdbf46 100644 > --- a/fs/xfs/xfs_inode.c > +++ b/fs/xfs/xfs_inode.c > @@ -3790,6 +3790,61 @@ xfs_iolock_two_inodes_and_break_layout( > return 0; > } > > +static int > +xfs_mmaplock_two_inodes_and_break_dax_layout( > + struct xfs_inode *ip1, > + struct xfs_inode *ip2) > +{ > + int error, attempts = 0; > + bool retry; > + struct page *page; > + struct xfs_log_item *lp; > + > + if (ip1->i_ino > ip2->i_ino) > + swap(ip1, ip2); > + > +again: > + retry = false; > + /* Lock the first inode */ > + xfs_ilock(ip1, XFS_MMAPLOCK_EXCL); > + error = xfs_break_dax_layouts(VFS_I(ip1), &retry); > + if (error || retry) { > + xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL); > + if (error == 0 && retry) > + goto again; > + return error; > + } > + > + if (ip1 == ip2) > + return 0; > + > + /* Nested lock the second inode */ > + lp = &ip1->i_itemp->ili_item; > + if (lp && test_bit(XFS_LI_IN_AIL, &lp->li_flags)) { > + if (!xfs_ilock_nowait(ip2, > + xfs_lock_inumorder(XFS_MMAPLOCK_EXCL, 1))) { > + xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL); > + if ((++attempts % 5) == 0) > + delay(1); /* Don't just spin the CPU */ > + goto again; > + } I suspect we don't need this part for grabbing the MMAPLOCK^W pagecache invalidatelock. The AIL only grabs the ILOCK, never the IOLOCK or the MMAPLOCK. > + } else > + xfs_ilock(ip2, xfs_lock_inumorder(XFS_MMAPLOCK_EXCL, 1)); > + /* > + * We cannot use xfs_break_dax_layouts() directly here because it may > + * need to unlock & lock the XFS_MMAPLOCK_EXCL which is not suitable > + * for this nested lock case. > + */ > + page = dax_layout_busy_page(VFS_I(ip2)->i_mapping); > + if (page && page_ref_count(page) != 1) { Do you think the patch "ext4/xfs: add page refcount helper" would be a good cleanup to head this series? https://lore.kernel.org/linux-xfs/20210913161604.31981-1-alex.sierra@amd.com/T/#m59cf7cd5c0d521ad487fa3a15d31c3865db88bdf The rest of the logic looks ok. --D > + xfs_iunlock(ip2, XFS_MMAPLOCK_EXCL); > + xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL); > + goto again; > + } > + > + return 0; > +} > + > /* > * Lock two inodes so that userspace cannot initiate I/O via file syscalls or > * mmap activity. > @@ -3804,8 +3859,19 @@ xfs_ilock2_io_mmap( > ret = xfs_iolock_two_inodes_and_break_layout(VFS_I(ip1), VFS_I(ip2)); > if (ret) > return ret; > - filemap_invalidate_lock_two(VFS_I(ip1)->i_mapping, > - VFS_I(ip2)->i_mapping); > + > + if (IS_DAX(VFS_I(ip1)) && IS_DAX(VFS_I(ip2))) { > + ret = xfs_mmaplock_two_inodes_and_break_dax_layout(ip1, ip2); > + if (ret) { > + inode_unlock(VFS_I(ip2)); > + if (ip1 != ip2) > + inode_unlock(VFS_I(ip1)); > + return ret; > + } > + } else > + filemap_invalidate_lock_two(VFS_I(ip1)->i_mapping, > + VFS_I(ip2)->i_mapping); > + > return 0; > } > > @@ -3815,8 +3881,14 @@ xfs_iunlock2_io_mmap( > struct xfs_inode *ip1, > struct xfs_inode *ip2) > { > - filemap_invalidate_unlock_two(VFS_I(ip1)->i_mapping, > - VFS_I(ip2)->i_mapping); > + if (IS_DAX(VFS_I(ip1)) && IS_DAX(VFS_I(ip2))) { > + xfs_iunlock(ip2, XFS_MMAPLOCK_EXCL); > + if (ip1 != ip2) > + xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL); > + } else > + filemap_invalidate_unlock_two(VFS_I(ip1)->i_mapping, > + VFS_I(ip2)->i_mapping); > + > inode_unlock(VFS_I(ip2)); > if (ip1 != ip2) > inode_unlock(VFS_I(ip1)); > diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h > index b21b177832d1..f7e26fe31a26 100644 > --- a/fs/xfs/xfs_inode.h > +++ b/fs/xfs/xfs_inode.h > @@ -472,6 +472,7 @@ enum xfs_prealloc_flags { > > int xfs_update_prealloc_flags(struct xfs_inode *ip, > enum xfs_prealloc_flags flags); > +int xfs_break_dax_layouts(struct inode *inode, bool *retry); > int xfs_break_layouts(struct inode *inode, uint *iolock, > enum layout_break_reason reason); > > diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c > index 9d876e268734..3b99c9dfcf0d 100644 > --- a/fs/xfs/xfs_reflink.c > +++ b/fs/xfs/xfs_reflink.c > @@ -1327,8 +1327,8 @@ xfs_reflink_remap_prep( > if (XFS_IS_REALTIME_INODE(src) || XFS_IS_REALTIME_INODE(dest)) > goto out_unlock; > > - /* Don't share DAX file data for now. */ > - if (IS_DAX(inode_in) || IS_DAX(inode_out)) > + /* Don't share DAX file data with non-DAX file. */ > + if (IS_DAX(inode_in) != IS_DAX(inode_out)) > goto out_unlock; > > if (!IS_DAX(inode_in)) > -- > 2.33.0 > > >