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 C2346C4CECE for ; Fri, 13 Mar 2020 14:47:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8ECFF206FA for ; Fri, 13 Mar 2020 14:47:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Ui9G3tPB" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726633AbgCMOrY (ORCPT ); Fri, 13 Mar 2020 10:47:24 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:34194 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726866AbgCMOrS (ORCPT ); Fri, 13 Mar 2020 10:47:18 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1584110837; 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=Yplta0JM6NXgDWsRcUDeFLldnRHzRhQcBot5AqQBLVg=; b=Ui9G3tPB93WQY/egSlWdsPLXiVDDHWOST64AjX7ENDICfe3tihWY1XAd99mcU8x+MctLUY QQaxnDEP1c7KI7/1fcZM1/sDub2zjK1/BtGBbaR81KP3iu5yIF4ChLYR+AH0h0EpbmBQKu OyYoottx9rPxzORhQck86IKId5+8quw= 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-256-5qHkPNeiPg2aEivCMIofRQ-1; Fri, 13 Mar 2020 10:47:15 -0400 X-MC-Unique: 5qHkPNeiPg2aEivCMIofRQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 59A718C7177; Fri, 13 Mar 2020 14:47:14 +0000 (UTC) Received: from bfoster (dhcp-41-2.bos.redhat.com [10.18.41.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F156D5DF2B; Fri, 13 Mar 2020 14:47:13 +0000 (UTC) Date: Fri, 13 Mar 2020 10:47:12 -0400 From: Brian Foster To: "Darrick J. Wong" Cc: linux-xfs@vger.kernel.org Subject: Re: [PATCH 1/7] xfs: introduce fake roots for ag-rooted btrees Message-ID: <20200313144712.GA11929@bfoster> References: <158398473036.1308059.18353233923283406961.stgit@magnolia> <158398473702.1308059.5932849079464881055.stgit@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <158398473702.1308059.5932849079464881055.stgit@magnolia> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Wed, Mar 11, 2020 at 08:45:37PM -0700, Darrick J. Wong wrote: > From: Darrick J. Wong > > Create an in-core fake root for AG-rooted btree types so that callers > can generate a whole new btree using the upcoming btree bulk load > function without making the new tree accessible from the rest of the > filesystem. It is up to the individual btree type to provide a function > to create a staged cursor (presumably with the appropriate callouts to > update the fakeroot) and then commit the staged root back into the > filesystem. > > Signed-off-by: Darrick J. Wong > --- > fs/xfs/libxfs/xfs_btree.c | 168 +++++++++++++++++++++++++++++++++++++++++++++ > fs/xfs/libxfs/xfs_btree.h | 30 ++++++++ > fs/xfs/xfs_trace.h | 28 ++++++++ > 3 files changed, 225 insertions(+), 1 deletion(-) > > > diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c > index 4ef9f0b42c7f..085bc070e804 100644 > --- a/fs/xfs/libxfs/xfs_btree.c > +++ b/fs/xfs/libxfs/xfs_btree.c ... > @@ -4908,3 +4910,169 @@ xfs_btree_has_more_records( > else > return block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK); > } > + ... > +/* > + * Initialize a AG-rooted btree cursor with the given AG btree fake root. The > + * btree cursor's bc_ops will be overridden as needed to make the staging > + * functionality work. If new_ops is not NULL, these new ops will be passed > + * out to the caller for further overriding. > + */ > +void > +xfs_btree_stage_afakeroot( > + struct xfs_btree_cur *cur, > + struct xbtree_afakeroot *afake, > + struct xfs_btree_ops **new_ops) > +{ > + struct xfs_btree_ops *nops; > + > + ASSERT(!(cur->bc_flags & XFS_BTREE_STAGING)); > + ASSERT(!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)); > + ASSERT(cur->bc_tp == NULL); > + > + nops = kmem_alloc(sizeof(struct xfs_btree_ops), KM_NOFS); > + memcpy(nops, cur->bc_ops, sizeof(struct xfs_btree_ops)); > + nops->alloc_block = xfs_btree_fakeroot_alloc_block; > + nops->free_block = xfs_btree_fakeroot_free_block; > + nops->init_ptr_from_cur = xfs_btree_fakeroot_init_ptr_from_cur; > + nops->set_root = xfs_btree_afakeroot_set_root; > + nops->dup_cursor = xfs_btree_fakeroot_dup_cursor; > + > + cur->bc_ag.afake = afake; > + cur->bc_nlevels = afake->af_levels; > + cur->bc_ops = nops; > + cur->bc_flags |= XFS_BTREE_STAGING; > + > + if (new_ops) > + *new_ops = nops; Curious why we have new_ops if the caller unconditionally assigns ->bc_ops to the same value..? That aside: Reviewed-by: Brian Foster > +} > + > +/* > + * Transform an AG-rooted staging btree cursor back into a regular cursor by > + * substituting a real btree root for the fake one and restoring normal btree > + * cursor ops. The caller must log the btree root change prior to calling > + * this. > + */ > +void > +xfs_btree_commit_afakeroot( > + struct xfs_btree_cur *cur, > + struct xfs_trans *tp, > + struct xfs_buf *agbp, > + const struct xfs_btree_ops *ops) > +{ > + ASSERT(cur->bc_flags & XFS_BTREE_STAGING); > + ASSERT(cur->bc_tp == NULL); > + > + trace_xfs_btree_commit_afakeroot(cur); > + > + kmem_free((void *)cur->bc_ops); > + cur->bc_ag.agbp = agbp; > + cur->bc_ops = ops; > + cur->bc_flags &= ~XFS_BTREE_STAGING; > + cur->bc_tp = tp; > +} > diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h > index 0d10bbd5223a..aa4a7bd40023 100644 > --- a/fs/xfs/libxfs/xfs_btree.h > +++ b/fs/xfs/libxfs/xfs_btree.h > @@ -179,7 +179,10 @@ union xfs_btree_irec { > > /* Per-AG btree information. */ > struct xfs_btree_cur_ag { > - struct xfs_buf *agbp; > + union { > + struct xfs_buf *agbp; > + struct xbtree_afakeroot *afake; /* fake ag header root */ > + }; > xfs_agnumber_t agno; > union { > struct { > @@ -235,6 +238,12 @@ typedef struct xfs_btree_cur > #define XFS_BTREE_LASTREC_UPDATE (1<<2) /* track last rec externally */ > #define XFS_BTREE_CRC_BLOCKS (1<<3) /* uses extended btree blocks */ > #define XFS_BTREE_OVERLAPPING (1<<4) /* overlapping intervals */ > +/* > + * The root of this btree is a fakeroot structure so that we can stage a btree > + * rebuild without leaving it accessible via primary metadata. The ops struct > + * is dynamically allocated and must be freed when the cursor is deleted. > + */ > +#define XFS_BTREE_STAGING (1<<5) > > > #define XFS_BTREE_NOERROR 0 > @@ -515,4 +524,23 @@ xfs_btree_islastblock( > return block->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK); > } > > +/* Fake root for an AG-rooted btree. */ > +struct xbtree_afakeroot { > + /* AG block number of the new btree root. */ > + xfs_agblock_t af_root; > + > + /* Height of the new btree. */ > + unsigned int af_levels; > + > + /* Number of blocks used by the btree. */ > + unsigned int af_blocks; > +}; > + > +/* Cursor interactions with with fake roots for AG-rooted btrees. */ > +void xfs_btree_stage_afakeroot(struct xfs_btree_cur *cur, > + struct xbtree_afakeroot *afake, > + struct xfs_btree_ops **new_ops); > +void xfs_btree_commit_afakeroot(struct xfs_btree_cur *cur, struct xfs_trans *tp, > + struct xfs_buf *agbp, const struct xfs_btree_ops *ops); > + > #endif /* __XFS_BTREE_H__ */ > diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h > index 059c3098a4a0..d8c229492973 100644 > --- a/fs/xfs/xfs_trace.h > +++ b/fs/xfs/xfs_trace.h > @@ -3605,6 +3605,34 @@ TRACE_EVENT(xfs_check_new_dalign, > __entry->calc_rootino) > ) > > +TRACE_EVENT(xfs_btree_commit_afakeroot, > + TP_PROTO(struct xfs_btree_cur *cur), > + TP_ARGS(cur), > + TP_STRUCT__entry( > + __field(dev_t, dev) > + __field(xfs_btnum_t, btnum) > + __field(xfs_agnumber_t, agno) > + __field(xfs_agblock_t, agbno) > + __field(unsigned int, levels) > + __field(unsigned int, blocks) > + ), > + TP_fast_assign( > + __entry->dev = cur->bc_mp->m_super->s_dev; > + __entry->btnum = cur->bc_btnum; > + __entry->agno = cur->bc_ag.agno; > + __entry->agbno = cur->bc_ag.afake->af_root; > + __entry->levels = cur->bc_ag.afake->af_levels; > + __entry->blocks = cur->bc_ag.afake->af_blocks; > + ), > + TP_printk("dev %d:%d btree %s ag %u levels %u blocks %u root %u", > + MAJOR(__entry->dev), MINOR(__entry->dev), > + __print_symbolic(__entry->btnum, XFS_BTNUM_STRINGS), > + __entry->agno, > + __entry->levels, > + __entry->blocks, > + __entry->agbno) > +) > + > #endif /* _TRACE_XFS_H */ > > #undef TRACE_INCLUDE_PATH >