[v2] xfs: get rid of unnecessary xfs_perag_{get,put} pairs
diff mbox series

Message ID 20200603121156.3399-1-hsiangkao@redhat.com
State Superseded
Headers show
Series
  • [v2] xfs: get rid of unnecessary xfs_perag_{get,put} pairs
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Commit Message

Gao Xiang June 3, 2020, 12:11 p.m. UTC
In the course of some operations, we look up the perag from
the mount multiple times to get or change perag information.
These are often very short pieces of code, so while the
lookup cost is generally low, the cost of the lookup is far
higher than the cost of the operation we are doing on the
perag.

Since we changed buffers to hold references to the perag
they are cached in, many modification contexts already hold
active references to the perag that are held across these
operations. This is especially true for any operation that
is serialised by an allocation group header buffer.

In these cases, we can just use the buffer's reference to
the perag to avoid needing to do lookups to access the
perag. This means that many operations don't need to do
perag lookups at all to access the perag because they've
already looked up objects that own persistent references
and hence can use that reference instead.

Cc: Dave Chinner <dchinner@redhat.com>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
---
changes since v1:
 - update the commit message suggested by Dave;
 - fold in all corresponding ASSERTs I made;
 - apply another trivial case xfs_ag_resv_rmapbt_free as well.
   the counterpart xfs_ag_resv_rmapbt_alloc also needed by
   scrub, which seems some way indirect though (I didn't
   trace into that path).

 fs/xfs/libxfs/xfs_ag.c             |  5 ++--
 fs/xfs/libxfs/xfs_ag_resv.h        | 12 ---------
 fs/xfs/libxfs/xfs_alloc.c          | 27 +++++++++-----------
 fs/xfs/libxfs/xfs_alloc_btree.c    | 10 +++-----
 fs/xfs/libxfs/xfs_ialloc.c         | 34 ++++++++++---------------
 fs/xfs/libxfs/xfs_refcount_btree.c |  5 ++--
 fs/xfs/libxfs/xfs_rmap_btree.c     | 11 ++++----
 fs/xfs/xfs_inode.c                 | 41 ++++++++++--------------------
 8 files changed, 54 insertions(+), 91 deletions(-)

Comments

Dave Chinner June 4, 2020, 9:59 p.m. UTC | #1
On Wed, Jun 03, 2020 at 08:11:56PM +0800, Gao Xiang wrote:
> In the course of some operations, we look up the perag from
> the mount multiple times to get or change perag information.
> These are often very short pieces of code, so while the
> lookup cost is generally low, the cost of the lookup is far
> higher than the cost of the operation we are doing on the
> perag.
> 
> Since we changed buffers to hold references to the perag
> they are cached in, many modification contexts already hold
> active references to the perag that are held across these
> operations. This is especially true for any operation that
> is serialised by an allocation group header buffer.
> 
> In these cases, we can just use the buffer's reference to
> the perag to avoid needing to do lookups to access the
> perag. This means that many operations don't need to do
> perag lookups at all to access the perag because they've
> already looked up objects that own persistent references
> and hence can use that reference instead.
> 
> Cc: Dave Chinner <dchinner@redhat.com>
> Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
> Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
> ---
> changes since v1:
>  - update the commit message suggested by Dave;
>  - fold in all corresponding ASSERTs I made;

Ok, I think we had a small misunderstanding there. I was trying to
say the asserts that were in the first patch were fine, but we
didn't really need any more because the new asserts mostly matched
an existing pattern.

I wasn't suggesting that we do this everywhere:

> diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c
> index 9d84007a5c65..4b8c7cb87b84 100644
> --- a/fs/xfs/libxfs/xfs_ag.c
> +++ b/fs/xfs/libxfs/xfs_ag.c
> @@ -563,7 +563,9 @@ xfs_ag_get_geometry(
>  	error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agf_bp);
>  	if (error)
>  		goto out_agi;
> -	pag = xfs_perag_get(mp, agno);
> +
> +	pag = agi_bp->b_pag;
> +	ASSERT(pag->pag_agno == agno);

.... because we've already checked this in xfs_ialloc_read_agi() a
few lines of code back up the function.

That's the pattern I was refering to - we tend to check
relationships when they are first brought into a context, then we
don't need to check them again in that context.  Hence the asserts
in xfs_ialloc_read_agi() and xfs_alloc_read_agf() effectively cover
all the places where we pull the pag from those buffers, and so
there's no need to validate the correct perag is attached to the
buffer every time we access it....

Cheers,

Dave.
Gao Xiang June 5, 2020, 1:44 a.m. UTC | #2
On Fri, Jun 05, 2020 at 07:59:17AM +1000, Dave Chinner wrote:
> On Wed, Jun 03, 2020 at 08:11:56PM +0800, Gao Xiang wrote:

...

> 
> Ok, I think we had a small misunderstanding there. I was trying to
> say the asserts that were in the first patch were fine, but we
> didn't really need any more because the new asserts mostly matched
> an existing pattern.
> 
> I wasn't suggesting that we do this everywhere:
> 
> > diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c
> > index 9d84007a5c65..4b8c7cb87b84 100644
> > --- a/fs/xfs/libxfs/xfs_ag.c
> > +++ b/fs/xfs/libxfs/xfs_ag.c
> > @@ -563,7 +563,9 @@ xfs_ag_get_geometry(
> >  	error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agf_bp);
> >  	if (error)
> >  		goto out_agi;
> > -	pag = xfs_perag_get(mp, agno);
> > +
> > +	pag = agi_bp->b_pag;
> > +	ASSERT(pag->pag_agno == agno);
> 
> .... because we've already checked this in xfs_ialloc_read_agi() a
> few lines of code back up the function.
> 
> That's the pattern I was refering to - we tend to check
> relationships when they are first brought into a context, then we
> don't need to check them again in that context.  Hence the asserts
> in xfs_ialloc_read_agi() and xfs_alloc_read_agf() effectively cover
> all the places where we pull the pag from those buffers, and so
> there's no need to validate the correct perag is attached to the
> buffer every time we access it....

Sorry about that, I folded in ASSERTs of my debugging code at that time.
Because that is the straight way to check if somewhere has strange due
to my modification, but some are unnecessary really, I didn't check that,
sorry about that. I will check again and remove unneeded ASSERTs
in the next version.

Thanks,
Gao Xiang

> 
> Cheers,
> 
> Dave.
> -- 
> Dave Chinner
> david@fromorbit.com
>

Patch
diff mbox series

diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c
index 9d84007a5c65..4b8c7cb87b84 100644
--- a/fs/xfs/libxfs/xfs_ag.c
+++ b/fs/xfs/libxfs/xfs_ag.c
@@ -563,7 +563,9 @@  xfs_ag_get_geometry(
 	error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agf_bp);
 	if (error)
 		goto out_agi;
-	pag = xfs_perag_get(mp, agno);
+
+	pag = agi_bp->b_pag;
+	ASSERT(pag->pag_agno == agno);
 
 	/* Fill out form. */
 	memset(ageo, 0, sizeof(*ageo));
@@ -583,7 +585,6 @@  xfs_ag_get_geometry(
 	xfs_ag_geom_health(pag, ageo);
 
 	/* Release resources. */
-	xfs_perag_put(pag);
 	xfs_buf_relse(agf_bp);
 out_agi:
 	xfs_buf_relse(agi_bp);
diff --git a/fs/xfs/libxfs/xfs_ag_resv.h b/fs/xfs/libxfs/xfs_ag_resv.h
index f3fd0ee9a7f7..8a8eb4bc48bb 100644
--- a/fs/xfs/libxfs/xfs_ag_resv.h
+++ b/fs/xfs/libxfs/xfs_ag_resv.h
@@ -37,16 +37,4 @@  xfs_ag_resv_rmapbt_alloc(
 	xfs_perag_put(pag);
 }
 
-static inline void
-xfs_ag_resv_rmapbt_free(
-	struct xfs_mount	*mp,
-	xfs_agnumber_t		agno)
-{
-	struct xfs_perag	*pag;
-
-	pag = xfs_perag_get(mp, agno);
-	xfs_ag_resv_free_extent(pag, XFS_AG_RESV_RMAPBT, NULL, 1);
-	xfs_perag_put(pag);
-}
-
 #endif	/* __XFS_AG_RESV_H__ */
diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index 203e74fa64aa..df89279bbe1b 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -710,13 +710,12 @@  xfs_alloc_read_agfl(
 STATIC int
 xfs_alloc_update_counters(
 	struct xfs_trans	*tp,
-	struct xfs_perag	*pag,
 	struct xfs_buf		*agbp,
 	long			len)
 {
 	struct xfs_agf		*agf = agbp->b_addr;
 
-	pag->pagf_freeblks += len;
+	agbp->b_pag->pagf_freeblks += len;
 	be32_add_cpu(&agf->agf_freeblks, len);
 
 	xfs_trans_agblocks_delta(tp, len);
@@ -1175,8 +1174,8 @@  xfs_alloc_ag_vextent(
 	}
 
 	if (!args->wasfromfl) {
-		error = xfs_alloc_update_counters(args->tp, args->pag,
-						  args->agbp,
+		ASSERT(args->pag == args->agbp->b_pag);
+		error = xfs_alloc_update_counters(args->tp, args->agbp,
 						  -((long)(args->len)));
 		if (error)
 			return error;
@@ -1887,7 +1886,6 @@  xfs_free_ag_extent(
 	enum xfs_ag_resv_type		type)
 {
 	struct xfs_mount		*mp;
-	struct xfs_perag		*pag;
 	struct xfs_btree_cur		*bno_cur;
 	struct xfs_btree_cur		*cnt_cur;
 	xfs_agblock_t			gtbno; /* start of right neighbor */
@@ -2167,10 +2165,9 @@  xfs_free_ag_extent(
 	/*
 	 * Update the freespace totals in the ag and superblock.
 	 */
-	pag = xfs_perag_get(mp, agno);
-	error = xfs_alloc_update_counters(tp, pag, agbp, len);
-	xfs_ag_resv_free_extent(pag, type, tp, len);
-	xfs_perag_put(pag);
+	ASSERT(agno == agbp->b_pag->pag_agno);
+	error = xfs_alloc_update_counters(tp, agbp, len);
+	xfs_ag_resv_free_extent(agbp->b_pag, type, tp, len);
 	if (error)
 		goto error0;
 
@@ -2689,7 +2686,8 @@  xfs_alloc_get_freelist(
 	if (be32_to_cpu(agf->agf_flfirst) == xfs_agfl_size(mp))
 		agf->agf_flfirst = 0;
 
-	pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno));
+	pag = agbp->b_pag;
+	ASSERT(pag->pag_agno == be32_to_cpu(agf->agf_seqno));
 	ASSERT(!pag->pagf_agflreset);
 	be32_add_cpu(&agf->agf_flcount, -1);
 	xfs_trans_agflist_delta(tp, -1);
@@ -2701,7 +2699,6 @@  xfs_alloc_get_freelist(
 		pag->pagf_btreeblks++;
 		logflags |= XFS_AGF_BTREEBLKS;
 	}
-	xfs_perag_put(pag);
 
 	xfs_alloc_log_agf(tp, agbp, logflags);
 	*bnop = bno;
@@ -2797,7 +2794,8 @@  xfs_alloc_put_freelist(
 	if (be32_to_cpu(agf->agf_fllast) == xfs_agfl_size(mp))
 		agf->agf_fllast = 0;
 
-	pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno));
+	pag = agbp->b_pag;
+	ASSERT(pag->pag_agno == be32_to_cpu(agf->agf_seqno));
 	ASSERT(!pag->pagf_agflreset);
 	be32_add_cpu(&agf->agf_flcount, 1);
 	xfs_trans_agflist_delta(tp, 1);
@@ -2809,7 +2807,6 @@  xfs_alloc_put_freelist(
 		pag->pagf_btreeblks--;
 		logflags |= XFS_AGF_BTREEBLKS;
 	}
-	xfs_perag_put(pag);
 
 	xfs_alloc_log_agf(tp, agbp, logflags);
 
@@ -3006,7 +3003,8 @@  xfs_alloc_read_agf(
 	ASSERT(!(*bpp)->b_error);
 
 	agf = (*bpp)->b_addr;
-	pag = xfs_perag_get(mp, agno);
+	pag = (*bpp)->b_pag;
+	ASSERT(pag->pag_agno == agno);
 	if (!pag->pagf_init) {
 		pag->pagf_freeblks = be32_to_cpu(agf->agf_freeblks);
 		pag->pagf_btreeblks = be32_to_cpu(agf->agf_btreeblks);
@@ -3034,7 +3032,6 @@  xfs_alloc_read_agf(
 		       be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]));
 	}
 #endif
-	xfs_perag_put(pag);
 	return 0;
 }
 
diff --git a/fs/xfs/libxfs/xfs_alloc_btree.c b/fs/xfs/libxfs/xfs_alloc_btree.c
index 60c453cb3ee3..c1d276f791ea 100644
--- a/fs/xfs/libxfs/xfs_alloc_btree.c
+++ b/fs/xfs/libxfs/xfs_alloc_btree.c
@@ -38,16 +38,15 @@  xfs_allocbt_set_root(
 {
 	struct xfs_buf		*agbp = cur->bc_ag.agbp;
 	struct xfs_agf		*agf = agbp->b_addr;
-	xfs_agnumber_t		seqno = be32_to_cpu(agf->agf_seqno);
 	int			btnum = cur->bc_btnum;
-	struct xfs_perag	*pag = xfs_perag_get(cur->bc_mp, seqno);
+	struct xfs_perag	*pag = agbp->b_pag;
 
 	ASSERT(ptr->s != 0);
+	ASSERT(pag->pag_agno == be32_to_cpu(agf->agf_seqno));
 
 	agf->agf_roots[btnum] = ptr->s;
 	be32_add_cpu(&agf->agf_levels[btnum], inc);
 	pag->pagf_levels[btnum] += inc;
-	xfs_perag_put(pag);
 
 	xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS);
 }
@@ -115,7 +114,6 @@  xfs_allocbt_update_lastrec(
 	int			reason)
 {
 	struct xfs_agf		*agf = cur->bc_ag.agbp->b_addr;
-	xfs_agnumber_t		seqno = be32_to_cpu(agf->agf_seqno);
 	struct xfs_perag	*pag;
 	__be32			len;
 	int			numrecs;
@@ -160,9 +158,9 @@  xfs_allocbt_update_lastrec(
 	}
 
 	agf->agf_longest = len;
-	pag = xfs_perag_get(cur->bc_mp, seqno);
+	pag = cur->bc_ag.agbp->b_pag;
+	ASSERT(pag->pag_agno == be32_to_cpu(agf->agf_seqno));
 	pag->pagf_longest = be32_to_cpu(len);
-	xfs_perag_put(pag);
 	xfs_alloc_log_agf(cur->bc_tp, cur->bc_ag.agbp, XFS_AGF_LONGEST);
 }
 
diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
index 7fcf62b324b0..53b156c9ec84 100644
--- a/fs/xfs/libxfs/xfs_ialloc.c
+++ b/fs/xfs/libxfs/xfs_ialloc.c
@@ -888,10 +888,10 @@  xfs_ialloc_ag_alloc(
 	 */
 	be32_add_cpu(&agi->agi_count, newlen);
 	be32_add_cpu(&agi->agi_freecount, newlen);
-	pag = xfs_perag_get(args.mp, agno);
+	pag = agbp->b_pag;
+	ASSERT(pag->pag_agno == agno);
 	pag->pagi_freecount += newlen;
 	pag->pagi_count += newlen;
-	xfs_perag_put(pag);
 	agi->agi_newino = cpu_to_be32(newino);
 
 	/*
@@ -1134,7 +1134,7 @@  xfs_dialloc_ag_inobt(
 	xfs_agnumber_t		agno = be32_to_cpu(agi->agi_seqno);
 	xfs_agnumber_t		pagno = XFS_INO_TO_AGNO(mp, parent);
 	xfs_agino_t		pagino = XFS_INO_TO_AGINO(mp, parent);
-	struct xfs_perag	*pag;
+	struct xfs_perag	*pag = agbp->b_pag;
 	struct xfs_btree_cur	*cur, *tcur;
 	struct xfs_inobt_rec_incore rec, trec;
 	xfs_ino_t		ino;
@@ -1143,8 +1143,7 @@  xfs_dialloc_ag_inobt(
 	int			i, j;
 	int			searchdistance = 10;
 
-	pag = xfs_perag_get(mp, agno);
-
+	ASSERT(pag->pag_agno == agno);
 	ASSERT(pag->pagi_init);
 	ASSERT(pag->pagi_inodeok);
 	ASSERT(pag->pagi_freecount > 0);
@@ -1384,14 +1383,12 @@  xfs_dialloc_ag_inobt(
 
 	xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
 	xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -1);
-	xfs_perag_put(pag);
 	*inop = ino;
 	return 0;
 error1:
 	xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
 error0:
 	xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
-	xfs_perag_put(pag);
 	return error;
 }
 
@@ -1587,7 +1584,6 @@  xfs_dialloc_ag(
 	xfs_agnumber_t			agno = be32_to_cpu(agi->agi_seqno);
 	xfs_agnumber_t			pagno = XFS_INO_TO_AGNO(mp, parent);
 	xfs_agino_t			pagino = XFS_INO_TO_AGINO(mp, parent);
-	struct xfs_perag		*pag;
 	struct xfs_btree_cur		*cur;	/* finobt cursor */
 	struct xfs_btree_cur		*icur;	/* inobt cursor */
 	struct xfs_inobt_rec_incore	rec;
@@ -1599,8 +1595,6 @@  xfs_dialloc_ag(
 	if (!xfs_sb_version_hasfinobt(&mp->m_sb))
 		return xfs_dialloc_ag_inobt(tp, agbp, parent, inop);
 
-	pag = xfs_perag_get(mp, agno);
-
 	/*
 	 * If pagino is 0 (this is the root inode allocation) use newino.
 	 * This must work because we've just allocated some.
@@ -1667,7 +1661,8 @@  xfs_dialloc_ag(
 	 */
 	be32_add_cpu(&agi->agi_freecount, -1);
 	xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
-	pag->pagi_freecount--;
+	ASSERT(agbp->b_pag->pag_agno == agno);
+	agbp->b_pag->pagi_freecount--;
 
 	xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -1);
 
@@ -1680,7 +1675,6 @@  xfs_dialloc_ag(
 
 	xfs_btree_del_cursor(icur, XFS_BTREE_NOERROR);
 	xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
-	xfs_perag_put(pag);
 	*inop = ino;
 	return 0;
 
@@ -1688,7 +1682,6 @@  xfs_dialloc_ag(
 	xfs_btree_del_cursor(icur, XFS_BTREE_ERROR);
 error_cur:
 	xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
-	xfs_perag_put(pag);
 	return error;
 }
 
@@ -1945,7 +1938,6 @@  xfs_difree_inobt(
 {
 	struct xfs_agi			*agi = agbp->b_addr;
 	xfs_agnumber_t			agno = be32_to_cpu(agi->agi_seqno);
-	struct xfs_perag		*pag;
 	struct xfs_btree_cur		*cur;
 	struct xfs_inobt_rec_incore	rec;
 	int				ilen;
@@ -2007,6 +1999,8 @@  xfs_difree_inobt(
 	if (!(mp->m_flags & XFS_MOUNT_IKEEP) &&
 	    rec.ir_free == XFS_INOBT_ALL_FREE &&
 	    mp->m_sb.sb_inopblock <= XFS_INODES_PER_CHUNK) {
+		struct xfs_perag	*pag = agbp->b_pag;
+
 		xic->deleted = true;
 		xic->first_ino = XFS_AGINO_TO_INO(mp, agno, rec.ir_startino);
 		xic->alloc = xfs_inobt_irec_to_allocmask(&rec);
@@ -2020,10 +2014,9 @@  xfs_difree_inobt(
 		be32_add_cpu(&agi->agi_count, -ilen);
 		be32_add_cpu(&agi->agi_freecount, -(ilen - 1));
 		xfs_ialloc_log_agi(tp, agbp, XFS_AGI_COUNT | XFS_AGI_FREECOUNT);
-		pag = xfs_perag_get(mp, agno);
+		ASSERT(pag->pag_agno == agno);
 		pag->pagi_freecount -= ilen - 1;
 		pag->pagi_count -= ilen;
-		xfs_perag_put(pag);
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_ICOUNT, -ilen);
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -(ilen - 1));
 
@@ -2049,9 +2042,8 @@  xfs_difree_inobt(
 		 */
 		be32_add_cpu(&agi->agi_freecount, 1);
 		xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
-		pag = xfs_perag_get(mp, agno);
-		pag->pagi_freecount++;
-		xfs_perag_put(pag);
+		ASSERT(agbp->b_pag->pag_agno == agno);
+		agbp->b_pag->pagi_freecount++;
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, 1);
 	}
 
@@ -2661,7 +2653,8 @@  xfs_ialloc_read_agi(
 		return error;
 
 	agi = (*bpp)->b_addr;
-	pag = xfs_perag_get(mp, agno);
+	pag = (*bpp)->b_pag;
+	ASSERT(pag->pag_agno == agno);
 	if (!pag->pagi_init) {
 		pag->pagi_freecount = be32_to_cpu(agi->agi_freecount);
 		pag->pagi_count = be32_to_cpu(agi->agi_count);
@@ -2674,7 +2667,6 @@  xfs_ialloc_read_agi(
 	 */
 	ASSERT(pag->pagi_freecount == be32_to_cpu(agi->agi_freecount) ||
 		XFS_FORCED_SHUTDOWN(mp));
-	xfs_perag_put(pag);
 	return 0;
 }
 
diff --git a/fs/xfs/libxfs/xfs_refcount_btree.c b/fs/xfs/libxfs/xfs_refcount_btree.c
index 7fd6044a4f78..f445a8e2d04e 100644
--- a/fs/xfs/libxfs/xfs_refcount_btree.c
+++ b/fs/xfs/libxfs/xfs_refcount_btree.c
@@ -37,15 +37,14 @@  xfs_refcountbt_set_root(
 {
 	struct xfs_buf		*agbp = cur->bc_ag.agbp;
 	struct xfs_agf		*agf = agbp->b_addr;
-	xfs_agnumber_t		seqno = be32_to_cpu(agf->agf_seqno);
-	struct xfs_perag	*pag = xfs_perag_get(cur->bc_mp, seqno);
+	struct xfs_perag	*pag = agbp->b_pag;
 
 	ASSERT(ptr->s != 0);
+	ASSERT(pag->pag_agno == be32_to_cpu(agf->agf_seqno));
 
 	agf->agf_refcount_root = ptr->s;
 	be32_add_cpu(&agf->agf_refcount_level, inc);
 	pag->pagf_refcount_level += inc;
-	xfs_perag_put(pag);
 
 	xfs_alloc_log_agf(cur->bc_tp, agbp,
 			XFS_AGF_REFCOUNT_ROOT | XFS_AGF_REFCOUNT_LEVEL);
diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c
index b7c05314d07c..be660b2fd422 100644
--- a/fs/xfs/libxfs/xfs_rmap_btree.c
+++ b/fs/xfs/libxfs/xfs_rmap_btree.c
@@ -63,16 +63,15 @@  xfs_rmapbt_set_root(
 {
 	struct xfs_buf		*agbp = cur->bc_ag.agbp;
 	struct xfs_agf		*agf = agbp->b_addr;
-	xfs_agnumber_t		seqno = be32_to_cpu(agf->agf_seqno);
 	int			btnum = cur->bc_btnum;
-	struct xfs_perag	*pag = xfs_perag_get(cur->bc_mp, seqno);
+	struct xfs_perag	*pag = agbp->b_pag;
 
 	ASSERT(ptr->s != 0);
+	ASSERT(pag->pag_agno == be32_to_cpu(agf->agf_seqno));
 
 	agf->agf_roots[btnum] = ptr->s;
 	be32_add_cpu(&agf->agf_levels[btnum], inc);
 	pag->pagf_levels[btnum] += inc;
-	xfs_perag_put(pag);
 
 	xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS);
 }
@@ -123,6 +122,7 @@  xfs_rmapbt_free_block(
 {
 	struct xfs_buf		*agbp = cur->bc_ag.agbp;
 	struct xfs_agf		*agf = agbp->b_addr;
+	struct xfs_perag	*pag;
 	xfs_agblock_t		bno;
 	int			error;
 
@@ -139,8 +139,9 @@  xfs_rmapbt_free_block(
 			      XFS_EXTENT_BUSY_SKIP_DISCARD);
 	xfs_trans_agbtree_delta(cur->bc_tp, -1);
 
-	xfs_ag_resv_rmapbt_free(cur->bc_mp, cur->bc_ag.agno);
-
+	pag = cur->bc_ag.agbp->b_pag;
+	ASSERT(pag->pag_agno == cur->bc_ag.agno);
+	xfs_ag_resv_free_extent(pag, XFS_AG_RESV_RMAPBT, NULL, 1);
 	return 0;
 }
 
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 64f5f9a440ae..bcc5a6eb6a50 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2248,7 +2248,6 @@  xfs_iunlink(
 	}
 
 	if (next_agino != NULLAGINO) {
-		struct xfs_perag	*pag;
 		xfs_agino_t		old_agino;
 
 		/*
@@ -2265,9 +2264,8 @@  xfs_iunlink(
 		 * agino has been unlinked, add a backref from the next inode
 		 * back to agino.
 		 */
-		pag = xfs_perag_get(mp, agno);
-		error = xfs_iunlink_add_backref(pag, agino, next_agino);
-		xfs_perag_put(pag);
+		ASSERT(agibp->b_pag->pag_agno == agno);
+		error = xfs_iunlink_add_backref(agibp->b_pag, agino, next_agino);
 		if (error)
 			return error;
 	}
@@ -2403,7 +2401,6 @@  xfs_iunlink_remove(
 	struct xfs_buf		*agibp;
 	struct xfs_buf		*last_ibp;
 	struct xfs_dinode	*last_dip = NULL;
-	struct xfs_perag	*pag = NULL;
 	xfs_agnumber_t		agno = XFS_INO_TO_AGNO(mp, ip->i_ino);
 	xfs_agino_t		agino = XFS_INO_TO_AGINO(mp, ip->i_ino);
 	xfs_agino_t		next_agino;
@@ -2447,32 +2444,24 @@  xfs_iunlink_remove(
 	 * this inode's backref to point from the next inode.
 	 */
 	if (next_agino != NULLAGINO) {
-		pag = xfs_perag_get(mp, agno);
-		error = xfs_iunlink_change_backref(pag, next_agino,
+		ASSERT(agibp->b_pag->pag_agno == agno);
+		error = xfs_iunlink_change_backref(agibp->b_pag, next_agino,
 				NULLAGINO);
 		if (error)
-			goto out;
+			return error;
 	}
 
-	if (head_agino == agino) {
-		/* Point the head of the list to the next unlinked inode. */
-		error = xfs_iunlink_update_bucket(tp, agno, agibp, bucket_index,
-				next_agino);
-		if (error)
-			goto out;
-	} else {
+	if (head_agino != agino) {
 		struct xfs_imap	imap;
 		xfs_agino_t	prev_agino;
 
-		if (!pag)
-			pag = xfs_perag_get(mp, agno);
-
+		ASSERT(agibp->b_pag->pag_agno == agno);
 		/* We need to search the list for the inode being freed. */
 		error = xfs_iunlink_map_prev(tp, agno, head_agino, agino,
 				&prev_agino, &imap, &last_dip, &last_ibp,
-				pag);
+				agibp->b_pag);
 		if (error)
-			goto out;
+			return error;
 
 		/* Point the previous inode on the list to the next inode. */
 		xfs_iunlink_update_dinode(tp, agno, prev_agino, last_ibp,
@@ -2486,15 +2475,13 @@  xfs_iunlink_remove(
 		 * change_backref takes care of deleting the backref if
 		 * next_agino is NULLAGINO.
 		 */
-		error = xfs_iunlink_change_backref(pag, agino, next_agino);
-		if (error)
-			goto out;
+		return xfs_iunlink_change_backref(agibp->b_pag, agino,
+				next_agino);
 	}
 
-out:
-	if (pag)
-		xfs_perag_put(pag);
-	return error;
+	/* Point the head of the list to the next unlinked inode. */
+	return xfs_iunlink_update_bucket(tp, agno, agibp, bucket_index,
+			next_agino);
 }
 
 /*