xfs: add a perag to the btree cursor

Which will eventually completely replace the agno in it.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Brian Foster <bfoster@redhat.com>

21 files changed, 119 insertions, 70 deletions

diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index ce31c00dbf6f..7ec4af6bf494 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -776,7 +776,8 @@ xfs_alloc_cur_setup(
 	 */
 	if (!acur->cnt)
 		acur->cnt = xfs_allocbt_init_cursor(args->mp, args->tp,
-					args->agbp, args->agno, XFS_BTNUM_CNT);
+						args->agbp, args->agno,
+						args->pag, XFS_BTNUM_CNT);
 	error = xfs_alloc_lookup_ge(acur->cnt, 0, args->maxlen, &i);
 	if (error)
 		return error;
@@ -786,10 +787,12 @@ xfs_alloc_cur_setup(
 	 */
 	if (!acur->bnolt)
 		acur->bnolt = xfs_allocbt_init_cursor(args->mp, args->tp,
-					args->agbp, args->agno, XFS_BTNUM_BNO);
+						args->agbp, args->agno,
+						args->pag, XFS_BTNUM_BNO);
 	if (!acur->bnogt)
 		acur->bnogt = xfs_allocbt_init_cursor(args->mp, args->tp,
-					args->agbp, args->agno, XFS_BTNUM_BNO);
+						args->agbp, args->agno,
+						args->pag, XFS_BTNUM_BNO);
 	return i == 1 ? 0 : -ENOSPC;
 }
 
@@ -1217,7 +1220,7 @@ xfs_alloc_ag_vextent_exact(
 	 * Allocate/initialize a cursor for the by-number freespace btree.
 	 */
 	bno_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
-					  args->agno, XFS_BTNUM_BNO);
+					  args->agno, args->pag, XFS_BTNUM_BNO);
 
 	/*
 	 * Lookup bno and minlen in the btree (minlen is irrelevant, really).
@@ -1277,7 +1280,7 @@ xfs_alloc_ag_vextent_exact(
 	 * Allocate/initialize a cursor for the by-size btree.
 	 */
 	cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
-		args->agno, XFS_BTNUM_CNT);
+					args->agno, args->pag, XFS_BTNUM_CNT);
 	ASSERT(args->agbno + args->len <= be32_to_cpu(agf->agf_length));
 	error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen, args->agbno,
 				      args->len, XFSA_FIXUP_BNO_OK);
@@ -1674,7 +1677,7 @@ restart:
 	 * Allocate and initialize a cursor for the by-size btree.
 	 */
 	cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
-		args->agno, XFS_BTNUM_CNT);
+					args->agno, args->pag, XFS_BTNUM_CNT);
 	bno_cur = NULL;
 	busy = false;
 
@@ -1837,7 +1840,7 @@ restart:
 	 * Allocate and initialize a cursor for the by-block tree.
 	 */
 	bno_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
-		args->agno, XFS_BTNUM_BNO);
+					args->agno, args->pag, XFS_BTNUM_BNO);
 	if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen,
 			rbno, rlen, XFSA_FIXUP_CNT_OK)))
 		goto error0;
@@ -1909,7 +1912,8 @@ xfs_free_ag_extent(
 	/*
 	 * Allocate and initialize a cursor for the by-block btree.
 	 */
-	bno_cur = xfs_allocbt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_BNO);
+	bno_cur = xfs_allocbt_init_cursor(mp, tp, agbp, agno,
+					NULL, XFS_BTNUM_BNO);
 	/*
 	 * Look for a neighboring block on the left (lower block numbers)
 	 * that is contiguous with this space.
@@ -1979,7 +1983,8 @@ xfs_free_ag_extent(
 	/*
 	 * Now allocate and initialize a cursor for the by-size tree.
 	 */
-	cnt_cur = xfs_allocbt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_CNT);
+	cnt_cur = xfs_allocbt_init_cursor(mp, tp, agbp, agno,
+					NULL, XFS_BTNUM_CNT);
 	/*
 	 * Have both left and right contiguous neighbors.
 	 * Merge all three into a single free block.
@@ -2490,7 +2495,7 @@ xfs_exact_minlen_extent_available(
 	int			error = 0;
 
 	cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, agbp,
-			args->agno, XFS_BTNUM_CNT);
+					args->agno, args->pag, XFS_BTNUM_CNT);
 	error = xfs_alloc_lookup_ge(cnt_cur, 0, args->minlen, stat);
 	if (error)
 		goto out;
diff --git a/fs/xfs/libxfs/xfs_alloc_btree.c b/fs/xfs/libxfs/xfs_alloc_btree.c
index 19fdf87e86b9..a52ab25bbf0b 100644
--- a/fs/xfs/libxfs/xfs_alloc_btree.c
+++ b/fs/xfs/libxfs/xfs_alloc_btree.c
@@ -27,7 +27,7 @@ xfs_allocbt_dup_cursor(
 {
 	return xfs_allocbt_init_cursor(cur->bc_mp, cur->bc_tp,
 			cur->bc_ag.agbp, cur->bc_ag.agno,
-			cur->bc_btnum);
+			cur->bc_ag.pag, cur->bc_btnum);
 }
 
 STATIC void
@@ -473,6 +473,7 @@ xfs_allocbt_init_common(
 	struct xfs_mount	*mp,
 	struct xfs_trans	*tp,
 	xfs_agnumber_t		agno,
+	struct xfs_perag	*pag,
 	xfs_btnum_t		btnum)
 {
 	struct xfs_btree_cur	*cur;
@@ -497,6 +498,11 @@ xfs_allocbt_init_common(
 
 	cur->bc_ag.agno = agno;
 	cur->bc_ag.abt.active = false;
+	if (pag) {
+		/* take a reference for the cursor */
+		atomic_inc(&pag->pag_ref);
+	}
+	cur->bc_ag.pag = pag;
 
 	if (xfs_sb_version_hascrc(&mp->m_sb))
 		cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
@@ -513,12 +519,13 @@ xfs_allocbt_init_cursor(
 	struct xfs_trans	*tp,		/* transaction pointer */
 	struct xfs_buf		*agbp,		/* buffer for agf structure */
 	xfs_agnumber_t		agno,		/* allocation group number */
+	struct xfs_perag	*pag,
 	xfs_btnum_t		btnum)		/* btree identifier */
 {
 	struct xfs_agf		*agf = agbp->b_addr;
 	struct xfs_btree_cur	*cur;
 
-	cur = xfs_allocbt_init_common(mp, tp, agno, btnum);
+	cur = xfs_allocbt_init_common(mp, tp, agno, pag, btnum);
 	if (btnum == XFS_BTNUM_CNT)
 		cur->bc_nlevels = be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNT]);
 	else
@@ -539,7 +546,7 @@ xfs_allocbt_stage_cursor(
 {
 	struct xfs_btree_cur	*cur;
 
-	cur = xfs_allocbt_init_common(mp, NULL, agno, btnum);
+	cur = xfs_allocbt_init_common(mp, NULL, agno, NULL, btnum);
 	xfs_btree_stage_afakeroot(cur, afake);
 	return cur;
 }
diff --git a/fs/xfs/libxfs/xfs_alloc_btree.h b/fs/xfs/libxfs/xfs_alloc_btree.h
index a5b998e950fe..a10cedba18d8 100644
--- a/fs/xfs/libxfs/xfs_alloc_btree.h
+++ b/fs/xfs/libxfs/xfs_alloc_btree.h
@@ -13,6 +13,7 @@
 struct xfs_buf;
 struct xfs_btree_cur;
 struct xfs_mount;
+struct xfs_perag;
 struct xbtree_afakeroot;
 
 /*
@@ -48,7 +49,7 @@ struct xbtree_afakeroot;
 
 extern struct xfs_btree_cur *xfs_allocbt_init_cursor(struct xfs_mount *,
 		struct xfs_trans *, struct xfs_buf *,
-		xfs_agnumber_t, xfs_btnum_t);
+		xfs_agnumber_t, struct xfs_perag *pag, xfs_btnum_t);
 struct xfs_btree_cur *xfs_allocbt_stage_cursor(struct xfs_mount *mp,
 		struct xbtree_afakeroot *afake, xfs_agnumber_t agno,
 		xfs_btnum_t btnum);
diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index 0f12b885600d..44044317c0fb 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -377,6 +377,8 @@ xfs_btree_del_cursor(
 	       XFS_FORCED_SHUTDOWN(cur->bc_mp));
 	if (unlikely(cur->bc_flags & XFS_BTREE_STAGING))
 		kmem_free(cur->bc_ops);
+	if (!(cur->bc_flags & XFS_BTREE_LONG_PTRS) && cur->bc_ag.pag)
+		xfs_perag_put(cur->bc_ag.pag);
 	kmem_cache_free(xfs_btree_cur_zone, cur);
 }
 
diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index 10e50cbacacf..e71f33f1f111 100644
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -11,6 +11,7 @@ struct xfs_inode;
 struct xfs_mount;
 struct xfs_trans;
 struct xfs_ifork;
+struct xfs_perag;
 
 extern kmem_zone_t	*xfs_btree_cur_zone;
 
@@ -180,11 +181,12 @@ union xfs_btree_irec {
 
 /* Per-AG btree information. */
 struct xfs_btree_cur_ag {
+	xfs_agnumber_t		agno;
+	struct xfs_perag	*pag;
 	union {
 		struct xfs_buf		*agbp;
 		struct xbtree_afakeroot	*afake;	/* for staging cursor */
 	};
-	xfs_agnumber_t		agno;
 	union {
 		struct {
 			unsigned long nr_ops;	/* # record updates */
@@ -231,6 +233,13 @@ typedef struct xfs_btree_cur
 	uint8_t		bc_blocklog;	/* log2(blocksize) of btree blocks */
 	xfs_btnum_t	bc_btnum;	/* identifies which btree type */
 	int		bc_statoff;	/* offset of btre stats array */
+
+	/*
+	 * Short btree pointers need an agno to be able to turn the pointers
+	 * into physical addresses for IO, so the btree cursor switches between
+	 * bc_ino and bc_ag based on whether XFS_BTREE_LONG_PTRS is set for the
+	 * cursor.
+	 */
 	union {
 		struct xfs_btree_cur_ag	bc_ag;
 		struct xfs_btree_cur_ino bc_ino;
diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
index 8dc9225a5353..905872bab426 100644
--- a/fs/xfs/libxfs/xfs_ialloc.c
+++ b/fs/xfs/libxfs/xfs_ialloc.c
@@ -183,7 +183,7 @@ xfs_inobt_insert(
 	int			i;
 	int			error;
 
-	cur = xfs_inobt_init_cursor(mp, tp, agbp, agno, btnum);
+	cur = xfs_inobt_init_cursor(mp, tp, agbp, agno, NULL, btnum);
 
 	for (thisino = newino;
 	     thisino < newino + newlen;
@@ -531,7 +531,7 @@ xfs_inobt_insert_sprec(
 	int				i;
 	struct xfs_inobt_rec_incore	rec;
 
-	cur = xfs_inobt_init_cursor(mp, tp, agbp, agno, btnum);
+	cur = xfs_inobt_init_cursor(mp, tp, agbp, agno, NULL, btnum);
 
 	/* the new record is pre-aligned so we know where to look */
 	error = xfs_inobt_lookup(cur, nrec->ir_startino, XFS_LOOKUP_EQ, &i);
@@ -1145,7 +1145,7 @@ xfs_dialloc_ag_inobt(
 	ASSERT(pag->pagi_freecount > 0);
 
  restart_pagno:
-	cur = xfs_inobt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_INO);
+	cur = xfs_inobt_init_cursor(mp, tp, agbp, agno, NULL, XFS_BTNUM_INO);
 	/*
 	 * If pagino is 0 (this is the root inode allocation) use newino.
 	 * This must work because we've just allocated some.
@@ -1598,7 +1598,7 @@ xfs_dialloc_ag(
 	if (!pagino)
 		pagino = be32_to_cpu(agi->agi_newino);
 
-	cur = xfs_inobt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_FINO);
+	cur = xfs_inobt_init_cursor(mp, tp, agbp, agno, NULL, XFS_BTNUM_FINO);
 
 	error = xfs_check_agi_freecount(cur, agi);
 	if (error)
@@ -1641,7 +1641,7 @@ xfs_dialloc_ag(
 	 * the original freecount. If all is well, make the equivalent update to
 	 * the inobt using the finobt record and offset information.
 	 */
-	icur = xfs_inobt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_INO);
+	icur = xfs_inobt_init_cursor(mp, tp, agbp, agno, NULL, XFS_BTNUM_INO);
 
 	error = xfs_check_agi_freecount(icur, agi);
 	if (error)
@@ -1954,7 +1954,7 @@ xfs_difree_inobt(
 	/*
 	 * Initialize the cursor.
 	 */
-	cur = xfs_inobt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_INO);
+	cur = xfs_inobt_init_cursor(mp, tp, agbp, agno, NULL, XFS_BTNUM_INO);
 
 	error = xfs_check_agi_freecount(cur, agi);
 	if (error)
@@ -2080,7 +2080,7 @@ xfs_difree_finobt(
 	int				error;
 	int				i;
 
-	cur = xfs_inobt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_FINO);
+	cur = xfs_inobt_init_cursor(mp, tp, agbp, agno, NULL, XFS_BTNUM_FINO);
 
 	error = xfs_inobt_lookup(cur, ibtrec->ir_startino, XFS_LOOKUP_EQ, &i);
 	if (error)
@@ -2281,7 +2281,7 @@ xfs_imap_lookup(
 	 * we have a record, we need to ensure it contains the inode number
 	 * we are looking up.
 	 */
-	cur = xfs_inobt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_INO);
+	cur = xfs_inobt_init_cursor(mp, tp, agbp, agno, NULL, XFS_BTNUM_INO);
 	error = xfs_inobt_lookup(cur, agino, XFS_LOOKUP_LE, &i);
 	if (!error) {
 		if (i)
diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c
index 4ec8ea1331a5..6c4efdf01674 100644
--- a/fs/xfs/libxfs/xfs_ialloc_btree.c
+++ b/fs/xfs/libxfs/xfs_ialloc_btree.c
@@ -36,7 +36,7 @@ xfs_inobt_dup_cursor(
 {
 	return xfs_inobt_init_cursor(cur->bc_mp, cur->bc_tp,
 			cur->bc_ag.agbp, cur->bc_ag.agno,
-			cur->bc_btnum);
+			cur->bc_ag.pag, cur->bc_btnum);
 }
 
 STATIC void
@@ -429,6 +429,7 @@ xfs_inobt_init_common(
 	struct xfs_mount	*mp,		/* file system mount point */
 	struct xfs_trans	*tp,		/* transaction pointer */
 	xfs_agnumber_t		agno,		/* allocation group number */
+	struct xfs_perag	*pag,
 	xfs_btnum_t		btnum)		/* ialloc or free ino btree */
 {
 	struct xfs_btree_cur	*cur;
@@ -451,6 +452,11 @@ xfs_inobt_init_common(
 		cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
 
 	cur->bc_ag.agno = agno;
+	if (pag) {
+		/* take a reference for the cursor */
+		atomic_inc(&pag->pag_ref);
+	}
+	cur->bc_ag.pag = pag;
 	return cur;
 }
 
@@ -461,12 +467,13 @@ xfs_inobt_init_cursor(
 	struct xfs_trans	*tp,
 	struct xfs_buf		*agbp,
 	xfs_agnumber_t		agno,
+	struct xfs_perag	*pag,
 	xfs_btnum_t		btnum)
 {
 	struct xfs_btree_cur	*cur;
 	struct xfs_agi		*agi = agbp->b_addr;
 
-	cur = xfs_inobt_init_common(mp, tp, agno, btnum);
+	cur = xfs_inobt_init_common(mp, tp, agno, pag, btnum);
 	if (btnum == XFS_BTNUM_INO)
 		cur->bc_nlevels = be32_to_cpu(agi->agi_level);
 	else
@@ -485,7 +492,7 @@ xfs_inobt_stage_cursor(
 {
 	struct xfs_btree_cur	*cur;
 
-	cur = xfs_inobt_init_common(mp, NULL, agno, btnum);
+	cur = xfs_inobt_init_common(mp, NULL, agno, NULL, btnum);
 	xfs_btree_stage_afakeroot(cur, afake);
 	return cur;
 }
@@ -672,7 +679,7 @@ xfs_inobt_cur(
 	if (error)
 		return error;
 
-	cur = xfs_inobt_init_cursor(mp, tp, *agi_bpp, agno, which);
+	cur = xfs_inobt_init_cursor(mp, tp, *agi_bpp, agno, NULL, which);
 	*curpp = cur;
 	return 0;
 }
diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.h b/fs/xfs/libxfs/xfs_ialloc_btree.h
index d5afe01fb2de..04dfa7eee81f 100644
--- a/fs/xfs/libxfs/xfs_ialloc_btree.h
+++ b/fs/xfs/libxfs/xfs_ialloc_btree.h
@@ -13,6 +13,7 @@
 struct xfs_buf;
 struct xfs_btree_cur;
 struct xfs_mount;
+struct xfs_perag;
 
 /*
  * Btree block header size depends on a superblock flag.
@@ -45,9 +46,9 @@ struct xfs_mount;
 		 (maxrecs) * sizeof(xfs_inobt_key_t) + \
 		 ((index) - 1) * sizeof(xfs_inobt_ptr_t)))
 
-extern struct xfs_btree_cur *xfs_inobt_init_cursor(struct xfs_mount *,
-		struct xfs_trans *, struct xfs_buf *, xfs_agnumber_t,
-		xfs_btnum_t);
+extern struct xfs_btree_cur *xfs_inobt_init_cursor(struct xfs_mount *mp,
+		struct xfs_trans *tp, struct xfs_buf *agbp, xfs_agnumber_t agno,
+		struct xfs_perag *pag, xfs_btnum_t btnum);
 struct xfs_btree_cur *xfs_inobt_stage_cursor(struct xfs_mount *mp,
 		struct xbtree_afakeroot *afake, xfs_agnumber_t agno,
 		xfs_btnum_t btnum);
diff --git a/fs/xfs/libxfs/xfs_refcount.c b/fs/xfs/libxfs/xfs_refcount.c
index 2037b9f23069..1c2bd2949d7d 100644
--- a/fs/xfs/libxfs/xfs_refcount.c
+++ b/fs/xfs/libxfs/xfs_refcount.c
@@ -1178,7 +1178,7 @@ xfs_refcount_finish_one(
 		if (error)
 			return error;
 
-		rcur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno);
+		rcur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno, NULL);
 		rcur->bc_ag.refc.nr_ops = nr_ops;
 		rcur->bc_ag.refc.shape_changes = shape_changes;
 	}
@@ -1707,7 +1707,7 @@ xfs_refcount_recover_cow_leftovers(
 	error = xfs_alloc_read_agf(mp, tp, agno, 0, &agbp);
 	if (error)
 		goto out_trans;
-	cur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno);
+	cur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno, NULL);
 
 	/* Find all the leftover CoW staging extents. */
 	memset(&low, 0, sizeof(low));
diff --git a/fs/xfs/libxfs/xfs_refcount_btree.c b/fs/xfs/libxfs/xfs_refcount_btree.c
index c4ddf9ded00b..74f8ac0209f1 100644
--- a/fs/xfs/libxfs/xfs_refcount_btree.c
+++ b/fs/xfs/libxfs/xfs_refcount_btree.c
@@ -26,7 +26,7 @@ xfs_refcountbt_dup_cursor(
 	struct xfs_btree_cur	*cur)
 {
 	return xfs_refcountbt_init_cursor(cur->bc_mp, cur->bc_tp,
-			cur->bc_ag.agbp, cur->bc_ag.agno);
+			cur->bc_ag.agbp, cur->bc_ag.agno, cur->bc_ag.pag);
 }
 
 STATIC void
@@ -316,7 +316,8 @@ static struct xfs_btree_cur *
 xfs_refcountbt_init_common(
 	struct xfs_mount	*mp,
 	struct xfs_trans	*tp,
-	xfs_agnumber_t		agno)
+	xfs_agnumber_t		agno,
+	struct xfs_perag	*pag)
 {
 	struct xfs_btree_cur	*cur;
 
@@ -332,6 +333,11 @@ xfs_refcountbt_init_common(
 
 	cur->bc_ag.agno = agno;
 	cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
+	if (pag) {
+		/* take a reference for the cursor */
+		atomic_inc(&pag->pag_ref);
+	}
+	cur->bc_ag.pag = pag;
 
 	cur->bc_ag.refc.nr_ops = 0;
 	cur->bc_ag.refc.shape_changes = 0;
@@ -345,12 +351,13 @@ xfs_refcountbt_init_cursor(
 	struct xfs_mount	*mp,
 	struct xfs_trans	*tp,
 	struct xfs_buf		*agbp,
-	xfs_agnumber_t		agno)
+	xfs_agnumber_t		agno,
+	struct xfs_perag	*pag)
 {
 	struct xfs_agf		*agf = agbp->b_addr;
 	struct xfs_btree_cur	*cur;
 
-	cur = xfs_refcountbt_init_common(mp, tp, agno);
+	cur = xfs_refcountbt_init_common(mp, tp, agno, pag);
 	cur->bc_nlevels = be32_to_cpu(agf->agf_refcount_level);
 	cur->bc_ag.agbp = agbp;
 	return cur;
@@ -365,7 +372,7 @@ xfs_refcountbt_stage_cursor(
 {
 	struct xfs_btree_cur	*cur;
 
-	cur = xfs_refcountbt_init_common(mp, NULL, agno);
+	cur = xfs_refcountbt_init_common(mp, NULL, agno, NULL);
 	xfs_btree_stage_afakeroot(cur, afake);
 	return cur;
 }
diff --git a/fs/xfs/libxfs/xfs_refcount_btree.h b/fs/xfs/libxfs/xfs_refcount_btree.h
index eab1b0c672c0..8b82a39f104a 100644
--- a/fs/xfs/libxfs/xfs_refcount_btree.h
+++ b/fs/xfs/libxfs/xfs_refcount_btree.h
@@ -47,7 +47,7 @@ struct xbtree_afakeroot;
 
 extern struct xfs_btree_cur *xfs_refcountbt_init_cursor(struct xfs_mount *mp,
 		struct xfs_trans *tp, struct xfs_buf *agbp,
-		xfs_agnumber_t agno);
+		xfs_agnumber_t agno, struct xfs_perag *pag);
 struct xfs_btree_cur *xfs_refcountbt_stage_cursor(struct xfs_mount *mp,
 		struct xbtree_afakeroot *afake, xfs_agnumber_t agno);
 extern int xfs_refcountbt_maxrecs(int blocklen, bool leaf);
diff --git a/fs/xfs/libxfs/xfs_rmap.c b/fs/xfs/libxfs/xfs_rmap.c
index 1d0a6b686eea..0d7a6997120c 100644
--- a/fs/xfs/libxfs/xfs_rmap.c
+++ b/fs/xfs/libxfs/xfs_rmap.c
@@ -708,7 +708,7 @@ xfs_rmap_free(
 	if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
 		return 0;
 
-	cur = xfs_rmapbt_init_cursor(mp, tp, agbp, agno);
+	cur = xfs_rmapbt_init_cursor(mp, tp, agbp, agno, NULL);
 
 	error = xfs_rmap_unmap(cur, bno, len, false, oinfo);
 
@@ -962,7 +962,7 @@ xfs_rmap_alloc(
 	if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
 		return 0;
 
-	cur = xfs_rmapbt_init_cursor(mp, tp, agbp, agno);
+	cur = xfs_rmapbt_init_cursor(mp, tp, agbp, agno, NULL);
 	error = xfs_rmap_map(cur, bno, len, false, oinfo);
 
 	xfs_btree_del_cursor(cur, error);
@@ -2408,7 +2408,7 @@ xfs_rmap_finish_one(
 			goto out_drop;
 		}
 
-		rcur = xfs_rmapbt_init_cursor(mp, tp, agbp, pag->pag_agno);
+		rcur = xfs_rmapbt_init_cursor(mp, tp, agbp, pag->pag_agno, pag);
 	}
 	*pcur = rcur;
 
diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c
index ba2f7064451b..7bef8feeded1 100644
--- a/fs/xfs/libxfs/xfs_rmap_btree.c
+++ b/fs/xfs/libxfs/xfs_rmap_btree.c
@@ -52,7 +52,7 @@ xfs_rmapbt_dup_cursor(
 	struct xfs_btree_cur	*cur)
 {
 	return xfs_rmapbt_init_cursor(cur->bc_mp, cur->bc_tp,
-			cur->bc_ag.agbp, cur->bc_ag.agno);
+			cur->bc_ag.agbp, cur->bc_ag.agno, cur->bc_ag.pag);
 }
 
 STATIC void
@@ -449,7 +449,8 @@ static struct xfs_btree_cur *
 xfs_rmapbt_init_common(
 	struct xfs_mount	*mp,
 	struct xfs_trans	*tp,
-	xfs_agnumber_t		agno)
+	xfs_agnumber_t		agno,
+	struct xfs_perag	*pag)
 {
 	struct xfs_btree_cur	*cur;
 
@@ -463,6 +464,11 @@ xfs_rmapbt_init_common(
 	cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_rmap_2);
 	cur->bc_ag.agno = agno;
 	cur->bc_ops = &xfs_rmapbt_ops;
+	if (pag) {
+		/* take a reference for the cursor */
+		atomic_inc(&pag->pag_ref);
+	}
+	cur->bc_ag.pag = pag;
 
 	return cur;
 }
@@ -473,12 +479,13 @@ xfs_rmapbt_init_cursor(
 	struct xfs_mount	*mp,
 	struct xfs_trans	*tp,
 	struct xfs_buf		*agbp,
-	xfs_agnumber_t		agno)
+	xfs_agnumber_t		agno,
+	struct xfs_perag	*pag)
 {
 	struct xfs_agf		*agf = agbp->b_addr;
 	struct xfs_btree_cur	*cur;
 
-	cur = xfs_rmapbt_init_common(mp, tp, agno);
+	cur = xfs_rmapbt_init_common(mp, tp, agno, pag);
 	cur->bc_nlevels = be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]);
 	cur->bc_ag.agbp = agbp;
 	return cur;
@@ -493,7 +500,7 @@ xfs_rmapbt_stage_cursor(
 {
 	struct xfs_btree_cur	*cur;
 
-	cur = xfs_rmapbt_init_common(mp, NULL, agno);
+	cur = xfs_rmapbt_init_common(mp, NULL, agno, NULL);
 	xfs_btree_stage_afakeroot(cur, afake);
 	return cur;
 }
diff --git a/fs/xfs/libxfs/xfs_rmap_btree.h b/fs/xfs/libxfs/xfs_rmap_btree.h
index 57fab72e26ad..c94f418cc06b 100644
--- a/fs/xfs/libxfs/xfs_rmap_btree.h
+++ b/fs/xfs/libxfs/xfs_rmap_btree.h
@@ -43,7 +43,7 @@ struct xbtree_afakeroot;
 
 struct xfs_btree_cur *xfs_rmapbt_init_cursor(struct xfs_mount *mp,
 				struct xfs_trans *tp, struct xfs_buf *bp,
-				xfs_agnumber_t agno);
+				xfs_agnumber_t agno, struct xfs_perag *pag);
 struct xfs_btree_cur *xfs_rmapbt_stage_cursor(struct xfs_mount *mp,
 		struct xbtree_afakeroot *afake, xfs_agnumber_t agno);
 void xfs_rmapbt_commit_staged_btree(struct xfs_btree_cur *cur,
diff --git a/fs/xfs/scrub/agheader_repair.c b/fs/xfs/scrub/agheader_repair.c
index 1cdfbd57f36b..5dd91bf04c18 100644
--- a/fs/xfs/scrub/agheader_repair.c
+++ b/fs/xfs/scrub/agheader_repair.c
@@ -247,7 +247,7 @@ xrep_agf_calc_from_btrees(
 
 	/* Update the AGF counters from the bnobt. */
 	cur = xfs_allocbt_init_cursor(mp, sc->tp, agf_bp, sc->sa.agno,
-			XFS_BTNUM_BNO);
+			sc->sa.pag, XFS_BTNUM_BNO);
 	error = xfs_alloc_query_all(cur, xrep_agf_walk_allocbt, &raa);
 	if (error)
 		goto err;
@@ -261,7 +261,7 @@ xrep_agf_calc_from_btrees(
 
 	/* Update the AGF counters from the cntbt. */
 	cur = xfs_allocbt_init_cursor(mp, sc->tp, agf_bp, sc->sa.agno,
-			XFS_BTNUM_CNT);
+			sc->sa.pag, XFS_BTNUM_CNT);
 	error = xfs_btree_count_blocks(cur, &blocks);
 	if (error)
 		goto err;
@@ -269,7 +269,8 @@ xrep_agf_calc_from_btrees(
 	btreeblks += blocks - 1;
 
 	/* Update the AGF counters from the rmapbt. */
-	cur = xfs_rmapbt_init_cursor(mp, sc->tp, agf_bp, sc->sa.agno);
+	cur = xfs_rmapbt_init_cursor(mp, sc->tp, agf_bp, sc->sa.agno,
+			sc->sa.pag);
 	error = xfs_btree_count_blocks(cur, &blocks);
 	if (error)
 		goto err;
@@ -282,7 +283,7 @@ xrep_agf_calc_from_btrees(
 	/* Update the AGF counters from the refcountbt. */
 	if (xfs_sb_version_hasreflink(&mp->m_sb)) {
 		cur = xfs_refcountbt_init_cursor(mp, sc->tp, agf_bp,
-				sc->sa.agno);
+				sc->sa.agno, sc->sa.pag);
 		error = xfs_btree_count_blocks(cur, &blocks);
 		if (error)
 			goto err;
@@ -490,7 +491,8 @@ xrep_agfl_collect_blocks(
 	xbitmap_init(&ra.agmetablocks);
 
 	/* Find all space used by the free space btrees & rmapbt. */
-	cur = xfs_rmapbt_init_cursor(mp, sc->tp, agf_bp, sc->sa.agno);
+	cur = xfs_rmapbt_init_cursor(mp, sc->tp, agf_bp, sc->sa.agno,
+			sc->sa.pag);
 	error = xfs_rmap_query_all(cur, xrep_agfl_walk_rmap, &ra);
 	if (error)
 		goto err;
@@ -498,7 +500,7 @@ xrep_agfl_collect_blocks(
 
 	/* Find all blocks currently being used by the bnobt. */
 	cur = xfs_allocbt_init_cursor(mp, sc->tp, agf_bp, sc->sa.agno,
-			XFS_BTNUM_BNO);
+			sc->sa.pag, XFS_BTNUM_BNO);
 	error = xbitmap_set_btblocks(&ra.agmetablocks, cur);
 	if (error)
 		goto err;
@@ -506,7 +508,7 @@ xrep_agfl_collect_blocks(
 
 	/* Find all blocks currently being used by the cntbt. */
 	cur = xfs_allocbt_init_cursor(mp, sc->tp, agf_bp, sc->sa.agno,
-			XFS_BTNUM_CNT);
+			sc->sa.pag, XFS_BTNUM_CNT);
 	error = xbitmap_set_btblocks(&ra.agmetablocks, cur);
 	if (error)
 		goto err;
@@ -807,7 +809,7 @@ xrep_agi_calc_from_btrees(
 	int			error;
 
 	cur = xfs_inobt_init_cursor(mp, sc->tp, agi_bp, sc->sa.agno,
-			XFS_BTNUM_INO);
+			sc->sa.pag, XFS_BTNUM_INO);
 	error = xfs_ialloc_count_inodes(cur, &count, &freecount);
 	if (error)
 		goto err;
@@ -829,7 +831,7 @@ xrep_agi_calc_from_btrees(
 		xfs_agblock_t	blocks;
 
 		cur = xfs_inobt_init_cursor(mp, sc->tp, agi_bp, sc->sa.agno,
-				XFS_BTNUM_FINO);
+				sc->sa.pag, XFS_BTNUM_FINO);
 		error = xfs_btree_count_blocks(cur, &blocks);
 		if (error)
 			goto err;
diff --git a/fs/xfs/scrub/bmap.c b/fs/xfs/scrub/bmap.c
index e457c086887f..28fd4b961bb4 100644
--- a/fs/xfs/scrub/bmap.c
+++ b/fs/xfs/scrub/bmap.c
@@ -556,7 +556,7 @@ xchk_bmap_check_ag_rmaps(
 	if (error)
 		return error;
 
-	cur = xfs_rmapbt_init_cursor(sc->mp, sc->tp, agf, agno);
+	cur = xfs_rmapbt_init_cursor(sc->mp, sc->tp, agf, agno, NULL);
 
 	sbcri.sc = sc;
 	sbcri.whichfork = whichfork;
diff --git a/fs/xfs/scrub/common.c b/fs/xfs/scrub/common.c
index c8da976b50fc..50768559fb60 100644
--- a/fs/xfs/scrub/common.c
+++ b/fs/xfs/scrub/common.c
@@ -465,42 +465,42 @@ xchk_ag_btcur_init(
 	    xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_BNO)) {
 		/* Set up a bnobt cursor for cross-referencing. */
 		sa->bno_cur = xfs_allocbt_init_cursor(mp, sc->tp, sa->agf_bp,
-				agno, XFS_BTNUM_BNO);
+				agno, sa->pag, XFS_BTNUM_BNO);
 	}
 
 	if (sa->agf_bp &&
 	    xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_CNT)) {
 		/* Set up a cntbt cursor for cross-referencing. */
 		sa->cnt_cur = xfs_allocbt_init_cursor(mp, sc->tp, sa->agf_bp,
-				agno, XFS_BTNUM_CNT);
+				agno, sa->pag, XFS_BTNUM_CNT);
 	}
 
 	/* Set up a inobt cursor for cross-referencing. */
 	if (sa->agi_bp &&
 	    xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_INO)) {
 		sa->ino_cur = xfs_inobt_init_cursor(mp, sc->tp, sa->agi_bp,
-					agno, XFS_BTNUM_INO);
+				agno, sa->pag, XFS_BTNUM_INO);
 	}
 
 	/* Set up a finobt cursor for cross-referencing. */
 	if (sa->agi_bp && xfs_sb_version_hasfinobt(&mp->m_sb) &&
 	    xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_FINO)) {
 		sa->fino_cur = xfs_inobt_init_cursor(mp, sc->tp, sa->agi_bp,
-				agno, XFS_BTNUM_FINO);
+				agno, sa->pag, XFS_BTNUM_FINO);
 	}
 
 	/* Set up a rmapbt cursor for cross-referencing. */
 	if (sa->agf_bp && xfs_sb_version_hasrmapbt(&mp->m_sb) &&
 	    xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_RMAP)) {
 		sa->rmap_cur = xfs_rmapbt_init_cursor(mp, sc->tp, sa->agf_bp,
-				agno);
+				agno, sa->pag);
 	}
 
 	/* Set up a refcountbt cursor for cross-referencing. */
 	if (sa->agf_bp && xfs_sb_version_hasreflink(&mp->m_sb) &&
 	    xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_REFC)) {
 		sa->refc_cur = xfs_refcountbt_init_cursor(mp, sc->tp,
-				sa->agf_bp, agno);
+				sa->agf_bp, agno, sa->pag);
 	}
 }
 
diff --git a/fs/xfs/scrub/repair.c b/fs/xfs/scrub/repair.c
index 6b62872c4d10..862dc56fd8cd 100644
--- a/fs/xfs/scrub/repair.c
+++ b/fs/xfs/scrub/repair.c
@@ -555,7 +555,7 @@ xrep_reap_block(
 	} else {
 		agf_bp = sc->sa.agf_bp;
 	}
-	cur = xfs_rmapbt_init_cursor(sc->mp, sc->tp, agf_bp, agno);
+	cur = xfs_rmapbt_init_cursor(sc->mp, sc->tp, agf_bp, agno, sc->sa.pag);
 
 	/* Can we find any other rmappings? */
 	error = xfs_rmap_has_other_keys(cur, agbno, 1, oinfo, &has_other_rmap);
@@ -892,7 +892,8 @@ xrep_find_ag_btree_roots(
 		fab->height = 0;
 	}
 
-	cur = xfs_rmapbt_init_cursor(mp, sc->tp, agf_bp, sc->sa.agno);
+	cur = xfs_rmapbt_init_cursor(mp, sc->tp, agf_bp, sc->sa.agno,
+			sc->sa.pag);
 	error = xfs_rmap_query_all(cur, xrep_findroot_rmap, &ri);
 	xfs_btree_del_cursor(cur, error);
 
diff --git a/fs/xfs/xfs_discard.c b/fs/xfs/xfs_discard.c
index 972864250bd2..311ebaad4f5a 100644
--- a/fs/xfs/xfs_discard.c
+++ b/fs/xfs/xfs_discard.c
@@ -50,7 +50,7 @@ xfs_trim_extents(
 		goto out_put_perag;
 	agf = agbp->b_addr;
 
-	cur = xfs_allocbt_init_cursor(mp, NULL, agbp, agno, XFS_BTNUM_CNT);
+	cur = xfs_allocbt_init_cursor(mp, NULL, agbp, agno, pag, XFS_BTNUM_CNT);
 
 	/*
 	 * Look up the longest btree in the AGF and start with it.
diff --git a/fs/xfs/xfs_fsmap.c b/fs/xfs/xfs_fsmap.c
index 835dd6e3819b..b654a2bf9a9f 100644
--- a/fs/xfs/xfs_fsmap.c
+++ b/fs/xfs/xfs_fsmap.c
@@ -211,7 +211,7 @@ xfs_getfsmap_is_shared(
 	/* Are there any shared blocks here? */
 	flen = 0;
 	cur = xfs_refcountbt_init_cursor(mp, tp, info->agf_bp,
-			info->pag->pag_agno);
+			info->pag->pag_agno, info->pag);
 
 	error = xfs_refcount_find_shared(cur, rec->rm_startblock,
 			rec->rm_blockcount, &fbno, &flen, false);
@@ -708,7 +708,7 @@ xfs_getfsmap_datadev_rmapbt_query(
 
 	/* Allocate cursor for this AG and query_range it. */
 	*curpp = xfs_rmapbt_init_cursor(tp->t_mountp, tp, info->agf_bp,
-			info->pag->pag_agno);
+			info->pag->pag_agno, info->pag);
 	return xfs_rmap_query_range(*curpp, &info->low, &info->high,
 			xfs_getfsmap_datadev_helper, info);
 }
@@ -741,7 +741,7 @@ xfs_getfsmap_datadev_bnobt_query(
 
 	/* Allocate cursor for this AG and query_range it. */
 	*curpp = xfs_allocbt_init_cursor(tp->t_mountp, tp, info->agf_bp,
-			info->pag->pag_agno, XFS_BTNUM_BNO);
+			info->pag->pag_agno, info->pag, XFS_BTNUM_BNO);
 	key->ar_startblock = info->low.rm_startblock;
 	key[1].ar_startblock = info->high.rm_startblock;
 	return xfs_alloc_query_range(*curpp, key, &key[1],
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 0e430b0c1b16..28ffe1817f9b 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -144,7 +144,7 @@ xfs_reflink_find_shared(
 	if (error)
 		return error;
 
-	cur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno);
+	cur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno, NULL);
 
 	error = xfs_refcount_find_shared(cur, agbno, aglen, fbno, flen,
 			find_end_of_shared);