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Message-ID: <20240621205601.GX3058325@frogsfrogsfrogs>
Date: Fri, 21 Jun 2024 13:56:01 -0700
From: "Darrick J. Wong" <djwong@...nel.org>
To: Zizhi Wo <wozizhi@...wei.com>
Cc: chandan.babu@...cle.com, dchinner@...hat.com, linux-xfs@...r.kernel.org,
	linux-kernel@...r.kernel.org, yangerkun@...wei.com
Subject: Re: [PATCH] xfs: Avoid races with cnt_btree lastrec updates

On Fri, Jun 21, 2024 at 09:55:13AM +0800, Zizhi Wo wrote:
> 
> 
> 在 2024/6/21 9:40, Zizhi Wo 写道:
> > 
> > 
> > 在 2024/6/21 4:35, Darrick J. Wong 写道:
> > > On Wed, Jun 19, 2024 at 09:05:29AM +0800, Zizhi Wo wrote:
> > > > 
> > > > 
> > > > 在 2024/6/19 8:22, Darrick J. Wong 写道:
> > > > > On Tue, Jun 18, 2024 at 09:32:08PM +0800, Zizhi Wo wrote:
> > > > > > A concurrent file creation and little writing could
> > > > > > unexpectedly return
> > > > > > -ENOSPC error since there is a race window that the
> > > > > > allocator could get
> > > > > > the wrong agf->agf_longest.
> > > > > > 
> > > > > > Write file process steps:
> > > > > > 1) Find the entry that best meets the conditions, then
> > > > > > calculate the start
> > > > > >      address and length of the remaining part of the
> > > > > > entry after allocation.
> > > > > > 2) Delete this entry and update the agf->agf_longest.
> > > > > > 3) Insert the remaining unused parts of this entry based on the
> > > > > >      calculations in 1), and update the agf->agf_longest
> > > > > > again if necessary.
> > > > > > 
> > > > > > Create file process steps:
> > > > > > 1) Check whether there are free inodes in the inode chunk.
> > > > > > 2) If there is no free inode, check whether there has
> > > > > > space for creating
> > > > > >      inode chunks, perform the no-lock judgment first.
> > > > > > 3) If the judgment succeeds, the judgment is performed
> > > > > > again with agf lock
> > > > > >      held. Otherwire, an error is returned directly.
> > > > > > 
> > > > > > If the write process is in step 2) but not go to 3) yet,
> > > > > > the create file
> > > > > > process goes to 2) at this time, it will be mistaken for no space,
> > > > > > resulting in the file system still has space but the
> > > > > > file creation fails.
> > > > > > 
> > > > > > We have sent two different commits to the community in
> > > > > > order to fix this
> > > > > > problem[1][2]. Unfortunately, both solutions have flaws. In [2], I
> > > > > > discussed with Dave and Darrick, realized that a better
> > > > > > solution to this
> > > > > > problem requires the "last cnt record tracking" to be
> > > > > > ripped out of the
> > > > > > generic btree code. And surprisingly, Dave directly
> > > > > > provided his fix code.
> > > > > > This patch includes appropriate modifications based on his tmp-code to
> > > > > > address this issue.
> > > > > > 
> > > > > > The entire fix can be roughly divided into two parts:
> > > > > > 1) Delete the code related to lastrec-update in the
> > > > > > generic btree code.
> > > > > > 2) Place the process of updating longest freespace with
> > > > > > cntbt separately
> > > > > >      to the end of the cntbt modifications. And only
> > > > > > these two scenarios
> > > > > >      need to be considered:
> > > > > >      2.1) In the deletion scenario, directly update the longest to the
> > > > > >           rightmost record of the cntbt.
> > > > > >      2.2) In the insertion scenario, determine whether
> > > > > > the cntbt has the
> > > > > >           record that larger than the previous longest.
> > > > > > 
> > > > > > [1] https://lore.kernel.org/all/20240419061848.1032366-2-yebin10@huawei.com
> > > > > > [2] https://lore.kernel.org/all/20240604071121.3981686-1-wozizhi@huawei.com
> > > > > > 
> > > > > > Reported by: Ye Bin <yebin10@...wei.com>
> > > > > > Signed-off-by: Zizhi Wo <wozizhi@...wei.com>
> > > > > > ---
> > > > > >    fs/xfs/libxfs/xfs_alloc.c       | 116
> > > > > > ++++++++++++++++++++++++++++++++
> > > > > >    fs/xfs/libxfs/xfs_alloc_btree.c |  64 ------------------
> > > > > >    fs/xfs/libxfs/xfs_btree.c       |  51 --------------
> > > > > >    fs/xfs/libxfs/xfs_btree.h       |  16 ++---
> > > > > >    4 files changed, 120 insertions(+), 127 deletions(-)
> > > > > > 
> > > > > > diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
> > > > > > index 6c55a6e88eba..74e40f75a278 100644
> > > > > > --- a/fs/xfs/libxfs/xfs_alloc.c
> > > > > > +++ b/fs/xfs/libxfs/xfs_alloc.c
> > > > > > @@ -465,6 +465,99 @@ xfs_alloc_fix_len(
> > > > > >        args->len = rlen;
> > > > > >    }
> > > > > > +/*
> > > > > > + * Determine if the cursor points to the block that
> > > > > > contains the right-most
> > > > > > + * block of records in the by-count btree. This block
> > > > > > contains the largest
> > > > > > + * contiguous free extent in the AG, so if we modify ia
> > > > > > record in this block we
> > > > > 
> > > > >                                                           a record
> > > > > 
> > > > > > + * need to call xfs_alloc_fixup_longest() once the
> > > > > > modifications are done to
> > > > > > + * ensure the agf->agf_longest field is kept up to date
> > > > > > with the longest free
> > > > > > + * extent tracked by the by-count btree.
> > > > > > + */
> > > > > > +static bool
> > > > > > +xfs_alloc_cursor_at_lastrec(
> > > > > > +    struct xfs_btree_cur    *cnt_cur)
> > > > > > +{
> > > > > > +    struct xfs_btree_block    *block;
> > > > > > +    union xfs_btree_ptr    ptr;
> > > > > > +    struct xfs_buf        *bp;
> > > > > > +
> > > > > > +    block = xfs_btree_get_block(cnt_cur, 0, &bp);
> > > > > > +
> > > > > > +    xfs_btree_get_sibling(cnt_cur, block, &ptr, XFS_BB_RIGHTSIB);
> > > > > > +    if (!xfs_btree_ptr_is_null(cnt_cur, &ptr))
> > > > > > +        return false;
> > > > > > +    return true;
> > > > > > +}
> > > > > > +
> > > > > > +/*
> > > > > > + * Update the longest contiguous free extent in the AG
> > > > > > from the by-count cursor
> > > > > > + * that is passed to us. This should be done at the end
> > > > > > of any allocation or
> > > > > > + * freeing operation that touches the longest extent in the btree.
> > > > > > + *
> > > > > > + * Needing to update the longest extent can be determined by calling
> > > > > > + * xfs_alloc_cursor_at_lastrec() after the cursor is
> > > > > > positioned for record
> > > > > > + * modification but before the modification begins.
> > > > > > + */
> > > > > > +static int
> > > > > > +xfs_alloc_fixup_longest(
> > > > > > +    struct xfs_btree_cur    *cnt_cur,
> > > > > > +    int            reason)
> > > > > > +{
> > > > > > +    struct xfs_perag    *pag = cnt_cur->bc_ag.pag;
> > > > > > +    struct xfs_agf        *agf;
> > > > > > +    struct xfs_buf        *bp;
> > > > > > +    struct xfs_btree_block    *block;
> > > > > > +    int            error;
> > > > > > +    int            i;
> > > > > > +    int            numrecs;
> > > > > > +
> > > > > > +    /*
> > > > > > +     * Lookup last rec and update AGF.
> > > > > > +     *
> > > > > > +     * In case of LASTREC_DELREC, after called
> > > > > > xfs_alloc_lookup_ge(), the
> > > > > > +     * ptr is in the rightmost edge, and we need to
> > > > > > update the last record
> > > > > > +     * of this block as the longest free extent.
> > > > > > +     *
> > > > > > +     * In case of LASTREC_INSREC, because only one new
> > > > > > record is inserted
> > > > > > +     * each time, only need to check whether the cntbt
> > > > > > has a record that
> > > > > > +     * larger than the previous longest. Note that we
> > > > > > can't update the
> > > > > > +     * longest with xfs_alloc_get_rec() as the
> > > > > > xfs_verify_agbno() may not
> > > > > > +     * pass because pag->block_count is updated on the outside.
> > > > > > +     */
> > > > > > +    error = xfs_alloc_lookup_ge(cnt_cur, 0,
> > > > > > pag->pagf_longest + 1, &i);
> > > > > > +    if (error)
> > > > > > +        return error;
> > > > > > +
> > > > > > +    if (i == 1 || reason == LASTREC_DELREC) {
> > > > > > +        if (XFS_IS_CORRUPT(pag->pag_mount,
> > > > > > +                   i == 1 && reason == LASTREC_DELREC)) {
> > > > > > +            xfs_btree_mark_sick(cnt_cur);
> > > > > > +            return -EFSCORRUPTED;
> > > > > > +        }
> > > > > > +
> > > > > > +        block = xfs_btree_get_block(cnt_cur, 0, &bp);
> > > > > > +        numrecs = xfs_btree_get_numrecs(block);
> > > > > > +
> > > > > > +        if (numrecs) {
> > > > > > +            xfs_alloc_rec_t *rrp;
> > > > > > +
> > > > > > +            rrp = XFS_ALLOC_REC_ADDR(cnt_cur->bc_mp, block,
> > > > > > +                         numrecs);
> > > > > > +            pag->pagf_longest = be32_to_cpu(rrp->ar_blockcount);
> > > > > > +        } else {
> > > > > > +            /* empty tree */
> > > > > > +            pag->pagf_longest = 0;
> > > > > > +        }
> > > > > > +    }
> > > > > 
> > > > > Hum.  Would it work if we did:
> > > > > 
> > > > >     xfs_extlen_t    len;
> > > > > 
> > > > >     xfs_alloc_lookup_le(cnt_cur, 0, mp->m_sb.sb_agsize, &i);
> > > > > 
> > > > >     if (i)
> > > > >         xfs_alloc_get_rec(cnt_cur, ..., &len, &i);
> > > > >     if (!i)
> > > > >         len = 0;
> > > > > 
> > > > >     pag->pagf_longest = len;
> > > > > 
> > > > > This performs a LE lookup on the longest possible free extent (aka the
> > > > > AG size).  If we get pointed at a record, that's the longest
> > > > > free extent
> > > > > and we can set pag->pagf_longest to that.  If we get no record, then
> > > > > there's zero space and we can zero it.
> > > > > 
> > > > 
> > > > I checked it out, and it doesn't seem to work that way, for two reasons:
> > > > 1) In the insertion scenario, if the longest extent is continuous with
> > > > the extent to be inserted, the system deletes the longest extent first,
> > > > and then inserts a more longer extent. So in the last update, we should
> > > > not look at le, but ge.
> > > > 2) For the deletion scenario, because the start block is 0, the extent
> > > > value found is not the next longest extent value, but probably a very
> > > > small extent value (for example, its start block is very small), which
> > > > will also cause us to update incorrectly.
> > > > 
> > > > So in summary, I think it is appropriate to use ge here.
> > > 
> > > Ah, right, you're correct.
> > > 
> > > LE could work if you were willing to do:
> > > 
> > >     xfs_alloc_lookup_le(cnt_cur, mp->m_sb.sb_agsize,
> > >             mp->m_sb.sb_agsize, &i);
> > > 
> > > But you might as well stick with the GE lookup.
> > > 
> > > >                                                           On the other
> > > > hand, xfs_alloc_get_rec() introduces problems. As I wrote in the
> > > > comment, an internal call to xfs_verify_agbno() may fail because the
> > > > longest extent added, it could be greater than pag->block_count as
> > > > pag->block_count is later than the longest update.
> > > 
> > > Oh, because xfs_ag_extend_space (aka growfs) calls xfs_free_extent
> > > before updating pag->block_count.  But still, please don't use
> > > XFS_ALLOC_REC_ADDR when you already have a btree cursor handy.
> > > 
> > >     union xfs_btree_rec    *rec;
> > > 
> > >     xfs_alloc_lookup_ge(cnt_cur, 0, mp->m_sb.sb_agsize, &i);
> > >     if (i)
> > >         xfs_btree_get_rec(cur, &rec, &i);
> > >     if (i) {
> > >         struct xfs_alloc_rec_incore irec;
> > > 
> > >         /*
> > >          * pagf->block_count updates lag cntbt updates, so
> > >          * open-code the btree record access
> > >          */
> > >         xfs_alloc_btrec_to_irec(rec, &irec);
> > >         pagf->pagf_longest = irec.ar_blockcount;
> > >     } else {
> > >         /* empty tree */
> > >         pagf->pagf_longest = 0;
> > >     }
> > > 
> > > --D
> > > 
> > 
> > Thank you for pointing that out. Using XFS_ALLOC_REC_ADDR when already
> > holding a cursor indeed reduces efficiency. However, there are still two
> > points that I don't understand and worth discussing.
> > 1) Is the "mp->m_sb.sb_agsize" means "pag->pagf_longest"? Because I can
> > not find the "sb_agsize" definition in xfs_mount structure.

Oops, sorry.  I meant mp->m_sb.sb_agblocks.  It should always hold that
pagf_longest < sb_agblocks because the superblock (and sometimes the AG
headers) always consume the first block of an AG.  So no, I don't mean
pagf_longest or pagf_longest+1.  I really do intend to look up the
rightmost record in the by-length free space btree.

Perhaps a better solution than relying on sb_agblocks would simply be to
perform an LE lookup on the all-ones key so that the btree code dumps us
off at the rightmost record in the tree.

There should never be a record with ar_blockcount being all ones (let
alone a record with ar_blockcount and ar_startblock all ones) so this
will position the btree cursor at the rightmost record in the cntbt.
We no longer need to think about pagf_longest or pagf_longest+1.

int
xfs_cntbt_longest(
	struct xfs_btree_cur	*cur,
	xfs_extlen_t		*longest)
{
	struct xfs_alloc_rec_incore irec;
	union xfs_btree_rec	*rec;
	int			stat = 0;
	int			error;

	memset(&cur->bc_rec, 0xFF, sizeof(cur->bc_rec));
	error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, &stat);
	if (error)
		return error;
	if (!stat) {
		/* totally empty tree */
		*longest = 0;
		return 0;
	}

	error = xfs_btree_get_rec(cur, &rec, &stat);
	if (error)
		return error;
	if (!stat) {
		ASSERT(0);
		*longest = 0;
		return 0;
	}

	xfs_alloc_btrec_to_irec(rec, &irec);
	*longest = irec.ar_blockcount;
	return 0;
}

And then the fixup becomes:

STATIC int
xfs_alloc_fixup_longest(
	struct xfs_btree_cur	*cnt_cur)
{
	struct xfs_perag	*pag = cnt_cur->bc_ag.pag;
	struct xfs_buf		*bp = cnt_cur->bc_ag.agbp;
	struct xfs_agf		*agf = bp->b_addr;
	xfs_extlen_t		longest = 0;
	int			error;

	error = xfs_cntbt_longest(cnt_cur, &longest);
	if (error)
		return error;

	pag->pagf_longest = longest;
	agf->agf_longest = cpu_to_be32(pag->pagf_longest);
	xfs_alloc_log_agf(cnt_cur->bc_tp, bp, XFS_AGF_LONGEST);

	return 0;
}

> > 2) If "mp->m_sb.sb_agsize" means the longest, then in a deletion
> > scenario, if the record being deleted is not the longest, -i- in
> > xfs_alloc_lookup_ge() will be 0. The above code will incorrectly update
> > the longest to 0 instead of keeping it as original. Therefore, in this
> > scenario, would it be better to move the cursor one record to the left?
> > But if we move the cursor to the left, we still need to retrieve the
> > record. So, compared to directly calling XFS_ALLOC_REC_ADDR, I do not
> > know which approach is better...
> > 
> > These are my two points of confusion. I hope to get your answers. Thank
> > you very much!
> > 
> 
> Sorry, let me reframe my point...
> 1) If "mp->m_sb.sb_agsize" means "pag->pagf_longest", then the deletion
> scenario has no problem but the insertion has. Because at this time, the
> record we found based on the previous longest may no longer be the
> current largest.
> 2) If "mp->m_sb.sb_agsize" means "pag->pagf_longest + 1", then the
> insertion scenarios has no problem but the deletion has. The reason is
> what I described in the second point above: it may not find a record
> larger than longest + 1, and incorrectly update longest to 0.
> 
> So, to combine these two situations, I used the XFS_ALLOC_REC_ADDR
> even when a cursor was available...
> 
> 
> > Thanks,
> > Zizhi Wo
> > 
> > > > > Then I think you don't need the @reason argument either.
> > > > 
> > > > Mm-hm, the reasons for this will be removed from the comment and stated
> > > > next time in the commit message.
> > > > 
> > > > Thanks
> > > > Zizhi Wo
> > > > 
> > > > > 
> > > > > --D
> > > > 
> > > > > 
> > > > > > +
> > > > > > +    bp = cnt_cur->bc_ag.agbp;
> > > > > > +    agf = bp->b_addr;
> > > > > > +    agf->agf_longest = cpu_to_be32(pag->pagf_longest);
> > > > > > +    xfs_alloc_log_agf(cnt_cur->bc_tp, bp, XFS_AGF_LONGEST);
> > > > > > +
> > > > > > +    return 0;
> > > > > > +}
> > > > > > +
> > > > > >    /*
> > > > > >     * Update the two btrees, logically removing from
> > > > > > freespace the extent
> > > > > >     * starting at rbno, rlen blocks.  The extent is
> > > > > > contained within the
> > > > > > @@ -489,6 +582,7 @@ xfs_alloc_fixup_trees(
> > > > > >        xfs_extlen_t    nflen1=0;    /* first new free length */
> > > > > >        xfs_extlen_t    nflen2=0;    /* second new free length */
> > > > > >        struct xfs_mount *mp;
> > > > > > +    bool        fixup_longest = false;
> > > > > >        mp = cnt_cur->bc_mp;
> > > > > > @@ -577,6 +671,10 @@ xfs_alloc_fixup_trees(
> > > > > >            nfbno2 = rbno + rlen;
> > > > > >            nflen2 = (fbno + flen) - nfbno2;
> > > > > >        }
> > > > > > +
> > > > > > +    if (xfs_alloc_cursor_at_lastrec(cnt_cur))
> > > > > > +        fixup_longest = true;
> > > > > > +
> > > > > >        /*
> > > > > >         * Delete the entry from the by-size btree.
> > > > > >         */
> > > > > > @@ -654,6 +752,10 @@ xfs_alloc_fixup_trees(
> > > > > >                return -EFSCORRUPTED;
> > > > > >            }
> > > > > >        }
> > > > > > +
> > > > > > +    if (fixup_longest)
> > > > > > +        return xfs_alloc_fixup_longest(cnt_cur, LASTREC_DELREC);
> > > > > > +
> > > > > >        return 0;
> > > > > >    }
> > > > > > @@ -1956,6 +2058,7 @@ xfs_free_ag_extent(
> > > > > >        int                i;
> > > > > >        int                error;
> > > > > >        struct xfs_perag        *pag = agbp->b_pag;
> > > > > > +    bool                fixup_longest = false;
> > > > > >        bno_cur = cnt_cur = NULL;
> > > > > >        mp = tp->t_mountp;
> > > > > > @@ -2219,8 +2322,13 @@ xfs_free_ag_extent(
> > > > > >        }
> > > > > >        xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
> > > > > >        bno_cur = NULL;
> > > > > > +
> > > > > >        /*
> > > > > >         * In all cases we need to insert the new
> > > > > > freespace in the by-size tree.
> > > > > > +     *
> > > > > > +     * If this new freespace is being inserted in the
> > > > > > block that contains
> > > > > > +     * the largest free space in the btree, make sure
> > > > > > we also fix up the
> > > > > > +     * agf->agf-longest tracker field.
> > > > > >         */
> > > > > >        if ((error = xfs_alloc_lookup_eq(cnt_cur, nbno, nlen, &i)))
> > > > > >            goto error0;
> > > > > > @@ -2229,6 +2337,8 @@ xfs_free_ag_extent(
> > > > > >            error = -EFSCORRUPTED;
> > > > > >            goto error0;
> > > > > >        }
> > > > > > +    if (xfs_alloc_cursor_at_lastrec(cnt_cur))
> > > > > > +        fixup_longest = true;
> > > > > >        if ((error = xfs_btree_insert(cnt_cur, &i)))
> > > > > >            goto error0;
> > > > > >        if (XFS_IS_CORRUPT(mp, i != 1)) {
> > > > > > @@ -2236,6 +2346,12 @@ xfs_free_ag_extent(
> > > > > >            error = -EFSCORRUPTED;
> > > > > >            goto error0;
> > > > > >        }
> > > > > > +    if (fixup_longest) {
> > > > > > +        error = xfs_alloc_fixup_longest(cnt_cur, LASTREC_INSREC);
> > > > > > +        if (error)
> > > > > > +            goto error0;
> > > > > > +    }
> > > > > > +
> > > > > >        xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
> > > > > >        cnt_cur = NULL;
> > > > > > diff --git a/fs/xfs/libxfs/xfs_alloc_btree.c
> > > > > > b/fs/xfs/libxfs/xfs_alloc_btree.c
> > > > > > index 6ef5ddd89600..585e98e87ef9 100644
> > > > > > --- a/fs/xfs/libxfs/xfs_alloc_btree.c
> > > > > > +++ b/fs/xfs/libxfs/xfs_alloc_btree.c
> > > > > > @@ -115,67 +115,6 @@ xfs_allocbt_free_block(
> > > > > >        return 0;
> > > > > >    }
> > > > > > -/*
> > > > > > - * Update the longest extent in the AGF
> > > > > > - */
> > > > > > -STATIC void
> > > > > > -xfs_allocbt_update_lastrec(
> > > > > > -    struct xfs_btree_cur        *cur,
> > > > > > -    const struct xfs_btree_block    *block,
> > > > > > -    const union xfs_btree_rec    *rec,
> > > > > > -    int                ptr,
> > > > > > -    int                reason)
> > > > > > -{
> > > > > > -    struct xfs_agf        *agf = cur->bc_ag.agbp->b_addr;
> > > > > > -    struct xfs_perag    *pag;
> > > > > > -    __be32            len;
> > > > > > -    int            numrecs;
> > > > > > -
> > > > > > -    ASSERT(!xfs_btree_is_bno(cur->bc_ops));
> > > > > > -
> > > > > > -    switch (reason) {
> > > > > > -    case LASTREC_UPDATE:
> > > > > > -        /*
> > > > > > -         * If this is the last leaf block and it's the last record,
> > > > > > -         * then update the size of the longest extent in the AG.
> > > > > > -         */
> > > > > > -        if (ptr != xfs_btree_get_numrecs(block))
> > > > > > -            return;
> > > > > > -        len = rec->alloc.ar_blockcount;
> > > > > > -        break;
> > > > > > -    case LASTREC_INSREC:
> > > > > > -        if (be32_to_cpu(rec->alloc.ar_blockcount) <=
> > > > > > -            be32_to_cpu(agf->agf_longest))
> > > > > > -            return;
> > > > > > -        len = rec->alloc.ar_blockcount;
> > > > > > -        break;
> > > > > > -    case LASTREC_DELREC:
> > > > > > -        numrecs = xfs_btree_get_numrecs(block);
> > > > > > -        if (ptr <= numrecs)
> > > > > > -            return;
> > > > > > -        ASSERT(ptr == numrecs + 1);
> > > > > > -
> > > > > > -        if (numrecs) {
> > > > > > -            xfs_alloc_rec_t *rrp;
> > > > > > -
> > > > > > -            rrp = XFS_ALLOC_REC_ADDR(cur->bc_mp, block, numrecs);
> > > > > > -            len = rrp->ar_blockcount;
> > > > > > -        } else {
> > > > > > -            len = 0;
> > > > > > -        }
> > > > > > -
> > > > > > -        break;
> > > > > > -    default:
> > > > > > -        ASSERT(0);
> > > > > > -        return;
> > > > > > -    }
> > > > > > -
> > > > > > -    agf->agf_longest = len;
> > > > > > -    pag = cur->bc_ag.agbp->b_pag;
> > > > > > -    pag->pagf_longest = be32_to_cpu(len);
> > > > > > -    xfs_alloc_log_agf(cur->bc_tp, cur->bc_ag.agbp, XFS_AGF_LONGEST);
> > > > > > -}
> > > > > > -
> > > > > >    STATIC int
> > > > > >    xfs_allocbt_get_minrecs(
> > > > > >        struct xfs_btree_cur    *cur,
> > > > > > @@ -493,7 +432,6 @@ const struct xfs_btree_ops xfs_bnobt_ops = {
> > > > > >        .set_root        = xfs_allocbt_set_root,
> > > > > >        .alloc_block        = xfs_allocbt_alloc_block,
> > > > > >        .free_block        = xfs_allocbt_free_block,
> > > > > > -    .update_lastrec        = xfs_allocbt_update_lastrec,
> > > > > >        .get_minrecs        = xfs_allocbt_get_minrecs,
> > > > > >        .get_maxrecs        = xfs_allocbt_get_maxrecs,
> > > > > >        .init_key_from_rec    = xfs_allocbt_init_key_from_rec,
> > > > > > @@ -511,7 +449,6 @@ const struct xfs_btree_ops xfs_bnobt_ops = {
> > > > > >    const struct xfs_btree_ops xfs_cntbt_ops = {
> > > > > >        .name            = "cnt",
> > > > > >        .type            = XFS_BTREE_TYPE_AG,
> > > > > > -    .geom_flags        = XFS_BTGEO_LASTREC_UPDATE,
> > > > > >        .rec_len        = sizeof(xfs_alloc_rec_t),
> > > > > >        .key_len        = sizeof(xfs_alloc_key_t),
> > > > > > @@ -525,7 +462,6 @@ const struct xfs_btree_ops xfs_cntbt_ops = {
> > > > > >        .set_root        = xfs_allocbt_set_root,
> > > > > >        .alloc_block        = xfs_allocbt_alloc_block,
> > > > > >        .free_block        = xfs_allocbt_free_block,
> > > > > > -    .update_lastrec        = xfs_allocbt_update_lastrec,
> > > > > >        .get_minrecs        = xfs_allocbt_get_minrecs,
> > > > > >        .get_maxrecs        = xfs_allocbt_get_maxrecs,
> > > > > >        .init_key_from_rec    = xfs_allocbt_init_key_from_rec,
> > > > > > diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
> > > > > > index d29547572a68..a5c4af148853 100644
> > > > > > --- a/fs/xfs/libxfs/xfs_btree.c
> > > > > > +++ b/fs/xfs/libxfs/xfs_btree.c
> > > > > > @@ -1331,30 +1331,6 @@ xfs_btree_init_block_cur(
> > > > > >                xfs_btree_owner(cur));
> > > > > >    }
> > > > > > -/*
> > > > > > - * Return true if ptr is the last record in the btree and
> > > > > > - * we need to track updates to this record.  The decision
> > > > > > - * will be further refined in the update_lastrec method.
> > > > > > - */
> > > > > > -STATIC int
> > > > > > -xfs_btree_is_lastrec(
> > > > > > -    struct xfs_btree_cur    *cur,
> > > > > > -    struct xfs_btree_block    *block,
> > > > > > -    int            level)
> > > > > > -{
> > > > > > -    union xfs_btree_ptr    ptr;
> > > > > > -
> > > > > > -    if (level > 0)
> > > > > > -        return 0;
> > > > > > -    if (!(cur->bc_ops->geom_flags & XFS_BTGEO_LASTREC_UPDATE))
> > > > > > -        return 0;
> > > > > > -
> > > > > > -    xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
> > > > > > -    if (!xfs_btree_ptr_is_null(cur, &ptr))
> > > > > > -        return 0;
> > > > > > -    return 1;
> > > > > > -}
> > > > > > -
> > > > > >    STATIC void
> > > > > >    xfs_btree_buf_to_ptr(
> > > > > >        struct xfs_btree_cur    *cur,
> > > > > > @@ -2420,15 +2396,6 @@ xfs_btree_update(
> > > > > >        xfs_btree_copy_recs(cur, rp, rec, 1);
> > > > > >        xfs_btree_log_recs(cur, bp, ptr, ptr);
> > > > > > -    /*
> > > > > > -     * If we are tracking the last record in the tree and
> > > > > > -     * we are at the far right edge of the tree, update it.
> > > > > > -     */
> > > > > > -    if (xfs_btree_is_lastrec(cur, block, 0)) {
> > > > > > -        cur->bc_ops->update_lastrec(cur, block, rec,
> > > > > > -                        ptr, LASTREC_UPDATE);
> > > > > > -    }
> > > > > > -
> > > > > >        /* Pass new key value up to our parent. */
> > > > > >        if (xfs_btree_needs_key_update(cur, ptr)) {
> > > > > >            error = xfs_btree_update_keys(cur, 0);
> > > > > > @@ -3617,15 +3584,6 @@ xfs_btree_insrec(
> > > > > >                goto error0;
> > > > > >        }
> > > > > > -    /*
> > > > > > -     * If we are tracking the last record in the tree and
> > > > > > -     * we are at the far right edge of the tree, update it.
> > > > > > -     */
> > > > > > -    if (xfs_btree_is_lastrec(cur, block, level)) {
> > > > > > -        cur->bc_ops->update_lastrec(cur, block, rec,
> > > > > > -                        ptr, LASTREC_INSREC);
> > > > > > -    }
> > > > > > -
> > > > > >        /*
> > > > > >         * Return the new block number, if any.
> > > > > >         * If there is one, give back a record value and a cursor too.
> > > > > > @@ -3983,15 +3941,6 @@ xfs_btree_delrec(
> > > > > >        xfs_btree_set_numrecs(block, --numrecs);
> > > > > >        xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
> > > > > > -    /*
> > > > > > -     * If we are tracking the last record in the tree and
> > > > > > -     * we are at the far right edge of the tree, update it.
> > > > > > -     */
> > > > > > -    if (xfs_btree_is_lastrec(cur, block, level)) {
> > > > > > -        cur->bc_ops->update_lastrec(cur, block, NULL,
> > > > > > -                        ptr, LASTREC_DELREC);
> > > > > > -    }
> > > > > > -
> > > > > >        /*
> > > > > >         * We're at the root level.  First, shrink the
> > > > > > root block in-memory.
> > > > > >         * Try to get rid of the next level down.  If we
> > > > > > can't then there's
> > > > > > diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
> > > > > > index f93374278aa1..670470874630 100644
> > > > > > --- a/fs/xfs/libxfs/xfs_btree.h
> > > > > > +++ b/fs/xfs/libxfs/xfs_btree.h
> > > > > > @@ -154,12 +154,6 @@ struct xfs_btree_ops {
> > > > > >                       int *stat);
> > > > > >        int    (*free_block)(struct xfs_btree_cur *cur,
> > > > > > struct xfs_buf *bp);
> > > > > > -    /* update last record information */
> > > > > > -    void    (*update_lastrec)(struct xfs_btree_cur *cur,
> > > > > > -                  const struct xfs_btree_block *block,
> > > > > > -                  const union xfs_btree_rec *rec,
> > > > > > -                  int ptr, int reason);
> > > > > > -
> > > > > >        /* records in block/level */
> > > > > >        int    (*get_minrecs)(struct xfs_btree_cur *cur, int level);
> > > > > >        int    (*get_maxrecs)(struct xfs_btree_cur *cur, int level);
> > > > > > @@ -222,15 +216,13 @@ struct xfs_btree_ops {
> > > > > >    };
> > > > > >    /* btree geometry flags */
> > > > > > -#define XFS_BTGEO_LASTREC_UPDATE    (1U << 0) /* track
> > > > > > last rec externally */
> > > > > > -#define XFS_BTGEO_OVERLAPPING        (1U << 1) /*
> > > > > > overlapping intervals */
> > > > > > +#define XFS_BTGEO_OVERLAPPING        (1U << 0) /*
> > > > > > overlapping intervals */
> > > > > >    /*
> > > > > > - * Reasons for the update_lastrec method to be called.
> > > > > > + * Reasons for the xfs_alloc_fixup_longest() to be called.
> > > > > >     */
> > > > > > -#define LASTREC_UPDATE    0
> > > > > > -#define LASTREC_INSREC    1
> > > > > > -#define LASTREC_DELREC    2
> > > > > > +#define LASTREC_INSREC    0
> > > > > > +#define LASTREC_DELREC    1
> > > > > >    union xfs_btree_irec {
> > > > > > -- 
> > > > > > 2.39.2
> > > > > > 
> > 
> 

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