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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 5BD1EC43331 for ; Wed, 25 Mar 2020 13:30:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2588E2076A for ; Wed, 25 Mar 2020 13:30:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ePKF48XG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727277AbgCYNat (ORCPT ); Wed, 25 Mar 2020 09:30:49 -0400 Received: from us-smtp-delivery-74.mimecast.com ([63.128.21.74]:55766 "EHLO us-smtp-delivery-74.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726967AbgCYNat (ORCPT ); Wed, 25 Mar 2020 09:30:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1585143047; h=from:from:reply-to:subject:subject: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=1TwyIO13FF/FxwIcJZ+elAHugIzthIcFcVlJtGhRCcM=; b=ePKF48XGbsvDhCWKOo0sAuKRWnsopp5n7Dz0NHP7Rmr7N2gjG7RN9AHNkWmJo4+HQU8jfA Y/XnTgfCu79nr1rkzbRwht94gZJUh+oCLdmA9r599g/jTALfX21B1sIlf1GMyfZft9GuvJ Ds3uPol4sp1nbBAQzK610u5RwChi+tM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-486-Y-FsyP0LNUGaoytEB21aQA-1; Wed, 25 Mar 2020 09:30:42 -0400 X-MC-Unique: Y-FsyP0LNUGaoytEB21aQA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7C6F8800D5B; Wed, 25 Mar 2020 13:30:41 +0000 (UTC) Received: from bfoster (dhcp-41-2.bos.redhat.com [10.18.41.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 34B431001920; Wed, 25 Mar 2020 13:30:41 +0000 (UTC) Date: Wed, 25 Mar 2020 09:30:39 -0400 From: Brian Foster To: Dave Chinner Cc: linux-xfs@vger.kernel.org Subject: Re: [PATCH 8/8] xfs: factor inode lookup from xfs_ifree_cluster Message-ID: <20200325133039.GC11912@bfoster> References: <20200325014205.11843-1-david@fromorbit.com> <20200325014205.11843-9-david@fromorbit.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200325014205.11843-9-david@fromorbit.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Wed, Mar 25, 2020 at 12:42:05PM +1100, Dave Chinner wrote: > From: Dave Chinner > > There's lots of indent in this code which makes it a bit hard to > follow. We are also going to completely rework the inode lookup code > as part of the inode reclaim rework, so factor out the inode lookup > code from the inode cluster freeing code. > > Based on prototype code from Christoph Hellwig. > > Signed-off-by: Dave Chinner > --- https://lore.kernel.org/linux-xfs/20191104232000.GR4153244@magnolia/ https://lore.kernel.org/linux-xfs/20191101120521.GE59146@bfoster/ > fs/xfs/xfs_inode.c | 152 +++++++++++++++++++++++++-------------------- > 1 file changed, 84 insertions(+), 68 deletions(-) > > diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c > index 14b922f2a6db7..5c930863ed5b8 100644 > --- a/fs/xfs/xfs_inode.c > +++ b/fs/xfs/xfs_inode.c > @@ -2503,6 +2503,88 @@ xfs_iunlink_remove( > return error; > } > > +/* > + * Look up the inode number specified and mark it stale if it is found. If it is > + * dirty, return the inode so it can be attached to the cluster buffer so it can > + * be processed appropriately when the cluster free transaction completes. > + */ > +static struct xfs_inode * > +xfs_ifree_get_one_inode( > + struct xfs_perag *pag, > + struct xfs_inode *free_ip, > + int inum) > +{ > + struct xfs_mount *mp = pag->pag_mount; > + struct xfs_inode *ip; > + > +retry: > + rcu_read_lock(); > + ip = radix_tree_lookup(&pag->pag_ici_root, XFS_INO_TO_AGINO(mp, inum)); > + > + /* Inode not in memory, nothing to do */ > + if (!ip) > + goto out_rcu_unlock; > + > + /* > + * because this is an RCU protected lookup, we could find a recently > + * freed or even reallocated inode during the lookup. We need to check > + * under the i_flags_lock for a valid inode here. Skip it if it is not > + * valid, the wrong inode or stale. > + */ > + spin_lock(&ip->i_flags_lock); > + if (ip->i_ino != inum || __xfs_iflags_test(ip, XFS_ISTALE)) { > + spin_unlock(&ip->i_flags_lock); > + goto out_rcu_unlock; > + } > + spin_unlock(&ip->i_flags_lock); > + > + /* > + * Don't try to lock/unlock the current inode, but we _cannot_ skip the > + * other inodes that we did not find in the list attached to the buffer > + * and are not already marked stale. If we can't lock it, back off and > + * retry. > + */ > + if (ip != free_ip) { > + if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL)) { > + rcu_read_unlock(); > + delay(1); > + goto retry; > + } > + > + /* > + * Check the inode number again in case we're racing with > + * freeing in xfs_reclaim_inode(). See the comments in that > + * function for more information as to why the initial check is > + * not sufficient. > + */ > + if (ip->i_ino != inum) { > + xfs_iunlock(ip, XFS_ILOCK_EXCL); > + goto out_rcu_unlock; > + } > + } > + rcu_read_unlock(); > + > + xfs_iflock(ip); > + xfs_iflags_set(ip, XFS_ISTALE); > + > + /* > + * We don't need to attach clean inodes or those only with unlogged > + * changes (which we throw away, anyway). > + */ > + if (!ip->i_itemp || xfs_inode_clean(ip)) { > + ASSERT(ip != free_ip); > + xfs_ifunlock(ip); > + xfs_iunlock(ip, XFS_ILOCK_EXCL); > + goto out_no_inode; > + } > + return ip; > + > +out_rcu_unlock: > + rcu_read_unlock(); > +out_no_inode: > + return NULL; > +} > + > /* > * A big issue when freeing the inode cluster is that we _cannot_ skip any > * inodes that are in memory - they all must be marked stale and attached to > @@ -2603,77 +2685,11 @@ xfs_ifree_cluster( > * even trying to lock them. > */ > for (i = 0; i < igeo->inodes_per_cluster; i++) { > -retry: > - rcu_read_lock(); > - ip = radix_tree_lookup(&pag->pag_ici_root, > - XFS_INO_TO_AGINO(mp, (inum + i))); > - > - /* Inode not in memory, nothing to do */ > - if (!ip) { > - rcu_read_unlock(); > + ip = xfs_ifree_get_one_inode(pag, free_ip, inum + i); > + if (!ip) > continue; > - } > - > - /* > - * because this is an RCU protected lookup, we could > - * find a recently freed or even reallocated inode > - * during the lookup. We need to check under the > - * i_flags_lock for a valid inode here. Skip it if it > - * is not valid, the wrong inode or stale. > - */ > - spin_lock(&ip->i_flags_lock); > - if (ip->i_ino != inum + i || > - __xfs_iflags_test(ip, XFS_ISTALE)) { > - spin_unlock(&ip->i_flags_lock); > - rcu_read_unlock(); > - continue; > - } > - spin_unlock(&ip->i_flags_lock); > - > - /* > - * Don't try to lock/unlock the current inode, but we > - * _cannot_ skip the other inodes that we did not find > - * in the list attached to the buffer and are not > - * already marked stale. If we can't lock it, back off > - * and retry. > - */ > - if (ip != free_ip) { > - if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL)) { > - rcu_read_unlock(); > - delay(1); > - goto retry; > - } > - > - /* > - * Check the inode number again in case we're > - * racing with freeing in xfs_reclaim_inode(). > - * See the comments in that function for more > - * information as to why the initial check is > - * not sufficient. > - */ > - if (ip->i_ino != inum + i) { > - xfs_iunlock(ip, XFS_ILOCK_EXCL); > - rcu_read_unlock(); > - continue; > - } > - } > - rcu_read_unlock(); > > - xfs_iflock(ip); > - xfs_iflags_set(ip, XFS_ISTALE); > - > - /* > - * we don't need to attach clean inodes or those only > - * with unlogged changes (which we throw away, anyway). > - */ > iip = ip->i_itemp; > - if (!iip || xfs_inode_clean(ip)) { > - ASSERT(ip != free_ip); > - xfs_ifunlock(ip); > - xfs_iunlock(ip, XFS_ILOCK_EXCL); > - continue; > - } > - > iip->ili_last_fields = iip->ili_fields; > iip->ili_fields = 0; > iip->ili_fsync_fields = 0; > -- > 2.26.0.rc2 >