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, USER_AGENT_SANE_1 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 A6163FA3728 for ; Wed, 16 Oct 2019 15:26:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 64A66218DE for ; Wed, 16 Oct 2019 15:26:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394087AbfJPP0b (ORCPT ); Wed, 16 Oct 2019 11:26:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36432 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2394077AbfJPP0b (ORCPT ); Wed, 16 Oct 2019 11:26:31 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4573089F307; Wed, 16 Oct 2019 15:26:31 +0000 (UTC) Received: from bfoster (dhcp-41-2.bos.redhat.com [10.18.41.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CCF0D194B2; Wed, 16 Oct 2019 15:26:30 +0000 (UTC) Date: Wed, 16 Oct 2019 11:26:29 -0400 From: Brian Foster To: "Darrick J. Wong" Cc: linux-xfs@vger.kernel.org Subject: Re: [PATCH 1/4] xfs: introduce fake roots for ag-rooted btrees Message-ID: <20191016152629.GB41077@bfoster> References: <157063967800.2912204.4012307770844087647.stgit@magnolia> <157063968551.2912204.15634530264967900662.stgit@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <157063968551.2912204.15634530264967900662.stgit@magnolia> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.68]); Wed, 16 Oct 2019 15:26:31 +0000 (UTC) Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Wed, Oct 09, 2019 at 09:48:05AM -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 | 115 +++++++++++++++++++++++++++++++++++++++++++++ > fs/xfs/libxfs/xfs_btree.h | 43 +++++++++++++++-- > fs/xfs/xfs_trace.h | 28 +++++++++++ > 3 files changed, 181 insertions(+), 5 deletions(-) > > > diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c > index 71de937f9e64..7b18f0fa5e99 100644 > --- a/fs/xfs/libxfs/xfs_btree.c > +++ b/fs/xfs/libxfs/xfs_btree.c ... > @@ -4930,3 +4932,116 @@ xfs_btree_has_more_records( ... > +/* Initialize a pointer to the root block from the fakeroot. */ > +STATIC void > +xfs_btree_fakeroot_init_ptr_from_cur( > + struct xfs_btree_cur *cur, > + union xfs_btree_ptr *ptr) > +{ > + struct xbtree_afakeroot *afake; > + > + ASSERT(cur->bc_flags & XFS_BTREE_STAGING); > + > + if (cur->bc_flags & XFS_BTREE_LONG_PTRS) { > + ptr->l = cpu_to_be64(0); Why zero here? Is this just not supported? Otherwise this seems straightforward code-wise. I think I get the general idea, but it's hard to reason further about the pieces until I see the broader context.. Brian > + } else { > + afake = cur->bc_private.a.afake; > + ptr->s = cpu_to_be32(afake->af_root); > + } > +} > + > +/* Set the root block when our tree has a fakeroot. */ > +STATIC void > +xfs_btree_afakeroot_set_root( > + struct xfs_btree_cur *cur, > + union xfs_btree_ptr *ptr, > + int inc) > +{ > + struct xbtree_afakeroot *afake = cur->bc_private.a.afake; > + > + ASSERT(cur->bc_flags & XFS_BTREE_STAGING); > + afake->af_root = be32_to_cpu(ptr->s); > + afake->af_levels += inc; > +} > + > +/* > + * Initialize a AG-rooted btree cursor with the given AG @fakeroot, and prepare > + * @ops for overriding by duplicating them into @new_ops. The caller can > + * replace pointers in @new_ops as necessary once this call completes. Note > + * that staging cursors can only be used for bulk loading. > + */ > +void > +xfs_btree_stage_afakeroot( > + struct xfs_btree_cur *cur, > + struct xbtree_afakeroot *afake, > + const struct xfs_btree_ops *ops, > + struct xfs_btree_ops **new_ops) > +{ > + ASSERT(!(cur->bc_flags & XFS_BTREE_STAGING)); > + ASSERT(!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)); > + > + *new_ops = kmem_alloc(sizeof(struct xfs_btree_ops), KM_NOFS); > + memcpy(*new_ops, ops, sizeof(struct xfs_btree_ops)); > + (*new_ops)->alloc_block = xfs_btree_fakeroot_alloc_block; > + (*new_ops)->free_block = xfs_btree_fakeroot_free_block; > + (*new_ops)->init_ptr_from_cur = xfs_btree_fakeroot_init_ptr_from_cur; > + (*new_ops)->set_root = xfs_btree_afakeroot_set_root; > + (*new_ops)->dup_cursor = xfs_btree_fakeroot_dup_cursor; > + > + cur->bc_private.a.afake = afake; > + cur->bc_nlevels = afake->af_levels; > + cur->bc_ops = *new_ops; > + cur->bc_flags |= XFS_BTREE_STAGING; > +} > + > +/* > + * Transform an AG-rooted staging btree cursor back into a regular btree > + * cursor. Caller is responsible for logging changes before this. > + */ > +void > +xfs_btree_commit_afakeroot( > + struct xfs_btree_cur *cur, > + struct xfs_buf *agbp, > + const struct xfs_btree_ops *ops) > +{ > + ASSERT(cur->bc_flags & XFS_BTREE_STAGING); > + > + trace_xfs_btree_commit_afakeroot(cur); > + > + kmem_free((void *)cur->bc_ops); > + cur->bc_private.a.agbp = agbp; > + cur->bc_ops = ops; > + cur->bc_flags &= ~XFS_BTREE_STAGING; > +} > diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h > index ced1e65d1483..453de8a49e96 100644 > --- a/fs/xfs/libxfs/xfs_btree.h > +++ b/fs/xfs/libxfs/xfs_btree.h > @@ -185,6 +185,16 @@ union xfs_btree_cur_private { > } refc; > }; > > +/* Private information for a AG-rooted btree. */ > +struct xfs_btree_priv_ag { /* needed for BNO, CNT, INO */ > + union { > + struct xfs_buf *agbp; /* agf/agi buffer pointer */ > + struct xbtree_afakeroot *afake; /* fake ag header root */ > + }; > + xfs_agnumber_t agno; /* ag number */ > + union xfs_btree_cur_private priv; > +}; > + > /* > * Btree cursor structure. > * This collects all information needed by the btree code in one place. > @@ -206,11 +216,7 @@ typedef struct xfs_btree_cur > xfs_btnum_t bc_btnum; /* identifies which btree type */ > int bc_statoff; /* offset of btre stats array */ > union { > - struct { /* needed for BNO, CNT, INO */ > - struct xfs_buf *agbp; /* agf/agi buffer pointer */ > - xfs_agnumber_t agno; /* ag number */ > - union xfs_btree_cur_private priv; > - } a; > + struct xfs_btree_priv_ag a; > struct { /* needed for BMAP */ > struct xfs_inode *ip; /* pointer to our inode */ > int allocated; /* count of alloced */ > @@ -229,6 +235,12 @@ 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 > @@ -514,4 +526,25 @@ int xfs_btree_has_record(struct xfs_btree_cur *cur, union xfs_btree_irec *low, > union xfs_btree_irec *high, bool *exists); > bool xfs_btree_has_more_records(struct xfs_btree_cur *cur); > > +/* 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, > + const struct xfs_btree_ops *ops, > + struct xfs_btree_ops **new_ops); > +void xfs_btree_commit_afakeroot(struct xfs_btree_cur *cur, > + 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 eaae275ed430..e04ed5324696 100644 > --- a/fs/xfs/xfs_trace.h > +++ b/fs/xfs/xfs_trace.h > @@ -3609,6 +3609,34 @@ DEFINE_KMEM_EVENT(kmem_alloc_large); > DEFINE_KMEM_EVENT(kmem_realloc); > DEFINE_KMEM_EVENT(kmem_zone_alloc); > > +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_private.a.agno; > + __entry->agbno = cur->bc_private.a.afake->af_root; > + __entry->levels = cur->bc_private.a.afake->af_levels; > + __entry->blocks = cur->bc_private.a.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 >