diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c
index e60469fee875..47e90dbb852b 100644
--- a/fs/xfs/libxfs/xfs_ag.c
+++ b/fs/xfs/libxfs/xfs_ag.c
@@ -230,11 +230,8 @@ xfs_perag_alloc(
 #ifdef __KERNEL__
 	/* Place kernel structure only init below this point. */
 	spin_lock_init(&pag->pag_ici_lock);
-	spin_lock_init(&pag->pagb_lock);
 	INIT_DELAYED_WORK(&pag->pag_blockgc_work, xfs_blockgc_worker);
 	INIT_RADIX_TREE(&pag->pag_ici_root, GFP_ATOMIC);
-	init_waitqueue_head(&pag->pagb_wait);
-	pag->pagb_tree = RB_ROOT;
 #endif /* __KERNEL__ */
 
 	error = xfs_buf_cache_init(&pag->pag_bcache);
diff --git a/fs/xfs/libxfs/xfs_ag.h b/fs/xfs/libxfs/xfs_ag.h
index 042ee0913fb9..7290148fa6e6 100644
--- a/fs/xfs/libxfs/xfs_ag.h
+++ b/fs/xfs/libxfs/xfs_ag.h
@@ -80,11 +80,6 @@ struct xfs_perag {
 	uint8_t		pagf_repair_rmap_level;
 #endif
 
-	spinlock_t	pagb_lock;	/* lock for pagb_tree */
-	struct rb_root	pagb_tree;	/* ordered tree of busy extents */
-	unsigned int	pagb_gen;	/* generation count for pagb_tree */
-	wait_queue_head_t pagb_wait;	/* woken when pagb_gen changes */
-
 	atomic_t        pagf_fstrms;    /* # of filestreams active in this AG */
 
 	spinlock_t	pag_ici_lock;	/* incore inode cache lock */
diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index bfe7b4321c47..4ddd05c97a29 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -331,7 +331,8 @@ xfs_alloc_compute_aligned(
 	bool		busy;
 
 	/* Trim busy sections out of found extent */
-	busy = xfs_extent_busy_trim(args, &bno, &len, busy_gen);
+	busy = xfs_extent_busy_trim(pag_group(args->pag), args->minlen,
+			args->maxlen, &bno, &len, busy_gen);
 
 	/*
 	 * If we have a largish extent that happens to start before min_agbno,
@@ -1251,7 +1252,7 @@ xfs_alloc_ag_vextent_small(
 	if (fbno == NULLAGBLOCK)
 		goto out;
 
-	xfs_extent_busy_reuse(args->pag, fbno, 1,
+	xfs_extent_busy_reuse(pag_group(args->pag), fbno, 1,
 			      (args->datatype & XFS_ALLOC_NOBUSY));
 
 	if (args->datatype & XFS_ALLOC_USERDATA) {
@@ -1364,7 +1365,8 @@ xfs_alloc_ag_vextent_exact(
 	 */
 	tbno = fbno;
 	tlen = flen;
-	xfs_extent_busy_trim(args, &tbno, &tlen, &busy_gen);
+	xfs_extent_busy_trim(pag_group(args->pag), args->minlen, args->maxlen,
+			&tbno, &tlen, &busy_gen);
 
 	/*
 	 * Give up if the start of the extent is busy, or the freespace isn't
@@ -1757,8 +1759,9 @@ restart:
 			 * the allocation can be retried.
 			 */
 			trace_xfs_alloc_near_busy(args);
-			error = xfs_extent_busy_flush(args->tp, args->pag,
-					acur.busy_gen, alloc_flags);
+			error = xfs_extent_busy_flush(args->tp,
+					pag_group(args->pag), acur.busy_gen,
+					alloc_flags);
 			if (error)
 				goto out;
 
@@ -1873,8 +1876,9 @@ restart:
 			 * the allocation can be retried.
 			 */
 			trace_xfs_alloc_size_busy(args);
-			error = xfs_extent_busy_flush(args->tp, args->pag,
-					busy_gen, alloc_flags);
+			error = xfs_extent_busy_flush(args->tp,
+					pag_group(args->pag), busy_gen,
+					alloc_flags);
 			if (error)
 				goto error0;
 
@@ -1972,8 +1976,9 @@ restart:
 			 * the allocation can be retried.
 			 */
 			trace_xfs_alloc_size_busy(args);
-			error = xfs_extent_busy_flush(args->tp, args->pag,
-					busy_gen, alloc_flags);
+			error = xfs_extent_busy_flush(args->tp,
+					pag_group(args->pag), busy_gen,
+					alloc_flags);
 			if (error)
 				goto error0;
 
@@ -3615,8 +3620,8 @@ xfs_alloc_vextent_finish(
 		if (error)
 			goto out_drop_perag;
 
-		ASSERT(!xfs_extent_busy_search(args->pag, args->agbno,
-				args->len));
+		ASSERT(!xfs_extent_busy_search(pag_group(args->pag),
+				args->agbno, args->len));
 	}
 
 	xfs_ag_resv_alloc_extent(args->pag, args->resv, args);
@@ -4014,7 +4019,7 @@ __xfs_free_extent(
 
 	if (skip_discard)
 		busy_flags |= XFS_EXTENT_BUSY_SKIP_DISCARD;
-	xfs_extent_busy_insert(tp, pag, agbno, len, busy_flags);
+	xfs_extent_busy_insert(tp, pag_group(pag), agbno, len, busy_flags);
 	return 0;
 
 err_release:
diff --git a/fs/xfs/libxfs/xfs_alloc_btree.c b/fs/xfs/libxfs/xfs_alloc_btree.c
index 88e1545ed4c9..e69a1bb13f7f 100644
--- a/fs/xfs/libxfs/xfs_alloc_btree.c
+++ b/fs/xfs/libxfs/xfs_alloc_btree.c
@@ -86,7 +86,7 @@ xfs_allocbt_alloc_block(
 	}
 
 	atomic64_inc(&cur->bc_mp->m_allocbt_blks);
-	xfs_extent_busy_reuse(cur->bc_ag.pag, bno, 1, false);
+	xfs_extent_busy_reuse(pag_group(cur->bc_ag.pag), bno, 1, false);
 
 	new->s = cpu_to_be32(bno);
 
@@ -110,7 +110,7 @@ xfs_allocbt_free_block(
 		return error;
 
 	atomic64_dec(&cur->bc_mp->m_allocbt_blks);
-	xfs_extent_busy_insert(cur->bc_tp, agbp->b_pag, bno, 1,
+	xfs_extent_busy_insert(cur->bc_tp, pag_group(agbp->b_pag), bno, 1,
 			      XFS_EXTENT_BUSY_SKIP_DISCARD);
 	return 0;
 }
diff --git a/fs/xfs/libxfs/xfs_group.c b/fs/xfs/libxfs/xfs_group.c
index 8532dc2f8628..5c6fa5d76a91 100644
--- a/fs/xfs/libxfs/xfs_group.c
+++ b/fs/xfs/libxfs/xfs_group.c
@@ -10,6 +10,7 @@
 #include "xfs_mount.h"
 #include "xfs_error.h"
 #include "xfs_trace.h"
+#include "xfs_extent_busy.h"
 #include "xfs_group.h"
 
 /*
@@ -161,6 +162,9 @@ xfs_group_free(
 	XFS_IS_CORRUPT(mp, atomic_read(&xg->xg_ref) != 0);
 
 	xfs_defer_drain_free(&xg->xg_intents_drain);
+#ifdef __KERNEL__
+	kfree(xg->xg_busy_extents);
+#endif
 
 	if (uninit)
 		uninit(xg);
@@ -185,6 +189,9 @@ xfs_group_insert(
 	xg->xg_type = type;
 
 #ifdef __KERNEL__
+	xg->xg_busy_extents = xfs_extent_busy_alloc();
+	if (!xg->xg_busy_extents)
+		return -ENOMEM;
 	spin_lock_init(&xg->xg_state_lock);
 	xfs_hooks_init(&xg->xg_rmap_update_hooks);
 #endif
@@ -196,9 +203,14 @@ xfs_group_insert(
 	error = xa_insert(&mp->m_groups[type].xa, index, xg, GFP_KERNEL);
 	if (error) {
 		WARN_ON_ONCE(error == -EBUSY);
-		xfs_defer_drain_free(&xg->xg_intents_drain);
-		return error;
+		goto out_drain;
 	}
 
 	return 0;
+out_drain:
+	xfs_defer_drain_free(&xg->xg_intents_drain);
+#ifdef __KERNEL__
+	kfree(xg->xg_busy_extents);
+#endif
+	return error;
 }
diff --git a/fs/xfs/libxfs/xfs_group.h b/fs/xfs/libxfs/xfs_group.h
index a87b9b80ef75..0ff6e1d5635c 100644
--- a/fs/xfs/libxfs/xfs_group.h
+++ b/fs/xfs/libxfs/xfs_group.h
@@ -15,6 +15,11 @@ struct xfs_group {
 #ifdef __KERNEL__
 	/* -- kernel only structures below this line -- */
 
+	/*
+	 * Track freed but not yet committed extents.
+	 */
+	struct xfs_extent_busy_tree *xg_busy_extents;
+
 	/*
 	 * Bitsets of per-ag metadata that have been checked and/or are sick.
 	 * Callers should hold xg_state_lock before accessing this field.
diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c
index 6fd460fc7c9c..b37eaf37c7fd 100644
--- a/fs/xfs/libxfs/xfs_rmap_btree.c
+++ b/fs/xfs/libxfs/xfs_rmap_btree.c
@@ -102,7 +102,7 @@ xfs_rmapbt_alloc_block(
 		return 0;
 	}
 
-	xfs_extent_busy_reuse(pag, bno, 1, false);
+	xfs_extent_busy_reuse(pag_group(pag), bno, 1, false);
 
 	new->s = cpu_to_be32(bno);
 	be32_add_cpu(&agf->agf_rmap_blocks, 1);
@@ -136,7 +136,7 @@ xfs_rmapbt_free_block(
 	if (error)
 		return error;
 
-	xfs_extent_busy_insert(cur->bc_tp, pag, bno, 1,
+	xfs_extent_busy_insert(cur->bc_tp, pag_group(pag), bno, 1,
 			      XFS_EXTENT_BUSY_SKIP_DISCARD);
 
 	xfs_ag_resv_free_extent(pag, XFS_AG_RESV_RMAPBT, NULL, 1);
diff --git a/fs/xfs/scrub/alloc_repair.c b/fs/xfs/scrub/alloc_repair.c
index f07cd93012c6..0433363a90b6 100644
--- a/fs/xfs/scrub/alloc_repair.c
+++ b/fs/xfs/scrub/alloc_repair.c
@@ -132,13 +132,16 @@ int
 xrep_setup_ag_allocbt(
 	struct xfs_scrub	*sc)
 {
+	struct xfs_group	*xg = pag_group(sc->sa.pag);
+	unsigned int		busy_gen;
+
 	/*
 	 * Make sure the busy extent list is clear because we can't put extents
 	 * on there twice.
 	 */
-	if (xfs_extent_busy_list_empty(sc->sa.pag, &busy_gen))
+	if (xfs_extent_busy_list_empty(xg, &busy_gen))
 		return 0;
-	return xfs_extent_busy_flush(sc->tp, sc->sa.pag, busy_gen, 0);
+	return xfs_extent_busy_flush(sc->tp, xg, busy_gen, 0);
 }
 
 /* Check for any obvious conflicts in the free extent. */
@@ -866,7 +869,7 @@ xrep_allocbt(
 	 * on there twice.  In theory we cleared this before we started, but
 	 * let's not risk the filesystem.
 	 */
-	if (!xfs_extent_busy_list_empty(sc->sa.pag, &busy_gen)) {
+	if (!xfs_extent_busy_list_empty(pag_group(sc->sa.pag), &busy_gen)) {
 		error = -EDEADLOCK;
 		goto out_ra;
 	}
diff --git a/fs/xfs/scrub/reap.c b/fs/xfs/scrub/reap.c
index d65ad6aa856f..08230952053b 100644
--- a/fs/xfs/scrub/reap.c
+++ b/fs/xfs/scrub/reap.c
@@ -137,7 +137,7 @@ xreap_put_freelist(
 			agfl_bp, agbno, 0);
 	if (error)
 		return error;
-	xfs_extent_busy_insert(sc->tp, sc->sa.pag, agbno, 1,
+	xfs_extent_busy_insert(sc->tp, pag_group(sc->sa.pag), agbno, 1,
 			XFS_EXTENT_BUSY_SKIP_DISCARD);
 
 	return 0;
diff --git a/fs/xfs/xfs_discard.c b/fs/xfs/xfs_discard.c
index 739ec69c4428..019371c865d2 100644
--- a/fs/xfs/xfs_discard.c
+++ b/fs/xfs/xfs_discard.c
@@ -117,10 +117,12 @@ xfs_discard_extents(
 
 	blk_start_plug(&plug);
 	list_for_each_entry(busyp, &extents->extent_list, list) {
-		trace_xfs_discard_extent(busyp->pag, busyp->bno, busyp->length);
+		struct xfs_perag	*pag = to_perag(busyp->group);
+
+		trace_xfs_discard_extent(pag, busyp->bno, busyp->length);
 
 		error = __blkdev_issue_discard(mp->m_ddev_targp->bt_bdev,
-				xfs_agbno_to_daddr(busyp->pag, busyp->bno),
+				xfs_agbno_to_daddr(pag, busyp->bno),
 				XFS_FSB_TO_BB(mp, busyp->length),
 				GFP_KERNEL, &bio);
 		if (error && error != -EOPNOTSUPP) {
@@ -271,12 +273,12 @@ xfs_trim_gather_extents(
 		 * If any blocks in the range are still busy, skip the
 		 * discard and try again the next time.
 		 */
-		if (xfs_extent_busy_search(pag, fbno, flen)) {
+		if (xfs_extent_busy_search(pag_group(pag), fbno, flen)) {
 			trace_xfs_discard_busy(pag, fbno, flen);
 			goto next_extent;
 		}
 
-		xfs_extent_busy_insert_discard(pag, fbno, flen,
+		xfs_extent_busy_insert_discard(pag_group(pag), fbno, flen,
 				&extents->extent_list);
 next_extent:
 		if (tcur->by_bno)
diff --git a/fs/xfs/xfs_extent_busy.c b/fs/xfs/xfs_extent_busy.c
index 9c5c6279ae21..457a27ab8375 100644
--- a/fs/xfs/xfs_extent_busy.c
+++ b/fs/xfs/xfs_extent_busy.c
@@ -19,14 +19,22 @@
 #include "xfs_log.h"
 #include "xfs_ag.h"
 
+struct xfs_extent_busy_tree {
+	spinlock_t		eb_lock;
+	struct rb_root		eb_tree;
+	unsigned int		eb_gen;
+	wait_queue_head_t	eb_wait;
+};
+
 static void
 xfs_extent_busy_insert_list(
-	struct xfs_perag	*pag,
+	struct xfs_group	*xg,
 	xfs_agblock_t		bno,
 	xfs_extlen_t		len,
 	unsigned int		flags,
 	struct list_head	*busy_list)
 {
+	struct xfs_extent_busy_tree *eb = xg->xg_busy_extents;
 	struct xfs_extent_busy	*new;
 	struct xfs_extent_busy	*busyp;
 	struct rb_node		**rbp;
@@ -34,17 +42,17 @@ xfs_extent_busy_insert_list(
 
 	new = kzalloc(sizeof(struct xfs_extent_busy),
 			GFP_KERNEL | __GFP_NOFAIL);
-	new->pag = xfs_perag_hold(pag);
+	new->group = xfs_group_hold(xg);
 	new->bno = bno;
 	new->length = len;
 	INIT_LIST_HEAD(&new->list);
 	new->flags = flags;
 
 	/* trace before insert to be able to see failed inserts */
-	trace_xfs_extent_busy(pag_group(pag), bno, len);
+	trace_xfs_extent_busy(xg, bno, len);
 
-	spin_lock(&pag->pagb_lock);
-	rbp = &pag->pagb_tree.rb_node;
+	spin_lock(&eb->eb_lock);
+	rbp = &eb->eb_tree.rb_node;
 	while (*rbp) {
 		parent = *rbp;
 		busyp = rb_entry(parent, struct xfs_extent_busy, rb_node);
@@ -61,32 +69,32 @@ xfs_extent_busy_insert_list(
 	}
 
 	rb_link_node(&new->rb_node, parent, rbp);
-	rb_insert_color(&new->rb_node, &pag->pagb_tree);
+	rb_insert_color(&new->rb_node, &eb->eb_tree);
 
 	/* always process discard lists in fifo order */
 	list_add_tail(&new->list, busy_list);
-	spin_unlock(&pag->pagb_lock);
+	spin_unlock(&eb->eb_lock);
 }
 
 void
 xfs_extent_busy_insert(
 	struct xfs_trans	*tp,
-	struct xfs_perag	*pag,
+	struct xfs_group	*xg,
 	xfs_agblock_t		bno,
 	xfs_extlen_t		len,
 	unsigned int		flags)
 {
-	xfs_extent_busy_insert_list(pag, bno, len, flags, &tp->t_busy);
+	xfs_extent_busy_insert_list(xg, bno, len, flags, &tp->t_busy);
 }
 
 void
 xfs_extent_busy_insert_discard(
-	struct xfs_perag	*pag,
+	struct xfs_group	*xg,
 	xfs_agblock_t		bno,
 	xfs_extlen_t		len,
 	struct list_head	*busy_list)
 {
-	xfs_extent_busy_insert_list(pag, bno, len, XFS_EXTENT_BUSY_DISCARDED,
+	xfs_extent_busy_insert_list(xg, bno, len, XFS_EXTENT_BUSY_DISCARDED,
 			busy_list);
 }
 
@@ -101,17 +109,18 @@ xfs_extent_busy_insert_discard(
  */
 int
 xfs_extent_busy_search(
-	struct xfs_perag	*pag,
+	struct xfs_group	*xg,
 	xfs_agblock_t		bno,
 	xfs_extlen_t		len)
 {
+	struct xfs_extent_busy_tree *eb = xg->xg_busy_extents;
 	struct rb_node		*rbp;
 	struct xfs_extent_busy	*busyp;
 	int			match = 0;
 
 	/* find closest start bno overlap */
-	spin_lock(&pag->pagb_lock);
-	rbp = pag->pagb_tree.rb_node;
+	spin_lock(&eb->eb_lock);
+	rbp = eb->eb_tree.rb_node;
 	while (rbp) {
 		busyp = rb_entry(rbp, struct xfs_extent_busy, rb_node);
 		if (bno < busyp->bno) {
@@ -130,7 +139,7 @@ xfs_extent_busy_search(
 			break;
 		}
 	}
-	spin_unlock(&pag->pagb_lock);
+	spin_unlock(&eb->eb_lock);
 	return match;
 }
 
@@ -147,13 +156,15 @@ xfs_extent_busy_search(
  */
 STATIC bool
 xfs_extent_busy_update_extent(
-	struct xfs_perag	*pag,
+	struct xfs_group	*xg,
 	struct xfs_extent_busy	*busyp,
 	xfs_agblock_t		fbno,
 	xfs_extlen_t		flen,
-	bool			userdata) __releases(&pag->pagb_lock)
-					  __acquires(&pag->pagb_lock)
+	bool			userdata)
+		__releases(&eb->eb_lock)
+		__acquires(&eb->eb_lock)
 {
+	struct xfs_extent_busy_tree *eb = xg->xg_busy_extents;
 	xfs_agblock_t		fend = fbno + flen;
 	xfs_agblock_t		bbno = busyp->bno;
 	xfs_agblock_t		bend = bbno + busyp->length;
@@ -164,9 +175,9 @@ xfs_extent_busy_update_extent(
 	 * and retry.
 	 */
 	if (busyp->flags & XFS_EXTENT_BUSY_DISCARDED) {
-		spin_unlock(&pag->pagb_lock);
+		spin_unlock(&eb->eb_lock);
 		delay(1);
-		spin_lock(&pag->pagb_lock);
+		spin_lock(&eb->eb_lock);
 		return false;
 	}
 
@@ -239,7 +250,7 @@ xfs_extent_busy_update_extent(
 		 * tree root, because erasing the node can rearrange the
 		 * tree topology.
 		 */
-		rb_erase(&busyp->rb_node, &pag->pagb_tree);
+		rb_erase(&busyp->rb_node, &eb->eb_tree);
 		busyp->length = 0;
 		return false;
 	} else if (fend < bend) {
@@ -278,14 +289,14 @@ xfs_extent_busy_update_extent(
 		ASSERT(0);
 	}
 
-	trace_xfs_extent_busy_reuse(pag_group(pag), fbno, flen);
+	trace_xfs_extent_busy_reuse(xg, fbno, flen);
 	return true;
 
 out_force_log:
-	spin_unlock(&pag->pagb_lock);
-	xfs_log_force(pag_mount(pag), XFS_LOG_SYNC);
-	trace_xfs_extent_busy_force(pag_group(pag), fbno, flen);
-	spin_lock(&pag->pagb_lock);
+	spin_unlock(&eb->eb_lock);
+	xfs_log_force(xg->xg_mount, XFS_LOG_SYNC);
+	trace_xfs_extent_busy_force(xg, fbno, flen);
+	spin_lock(&eb->eb_lock);
 	return false;
 }
 
@@ -294,17 +305,18 @@ out_force_log:
  */
 void
 xfs_extent_busy_reuse(
-	struct xfs_perag	*pag,
+	struct xfs_group	*xg,
 	xfs_agblock_t		fbno,
 	xfs_extlen_t		flen,
 	bool			userdata)
 {
+	struct xfs_extent_busy_tree *eb = xg->xg_busy_extents;
 	struct rb_node		*rbp;
 
 	ASSERT(flen > 0);
-	spin_lock(&pag->pagb_lock);
+	spin_lock(&eb->eb_lock);
 restart:
-	rbp = pag->pagb_tree.rb_node;
+	rbp = eb->eb_tree.rb_node;
 	while (rbp) {
 		struct xfs_extent_busy *busyp =
 			rb_entry(rbp, struct xfs_extent_busy, rb_node);
@@ -319,11 +331,11 @@ restart:
 			continue;
 		}
 
-		if (!xfs_extent_busy_update_extent(pag, busyp, fbno, flen,
+		if (!xfs_extent_busy_update_extent(xg, busyp, fbno, flen,
 						  userdata))
 			goto restart;
 	}
-	spin_unlock(&pag->pagb_lock);
+	spin_unlock(&eb->eb_lock);
 }
 
 /*
@@ -332,7 +344,7 @@ restart:
  * args->minlen no suitable extent could be found, and the higher level
  * code needs to force out the log and retry the allocation.
  *
- * Return the current busy generation for the AG if the extent is busy. This
+ * Return the current busy generation for the group if the extent is busy. This
  * value can be used to wait for at least one of the currently busy extents
  * to be cleared. Note that the busy list is not guaranteed to be empty after
  * the gen is woken. The state of a specific extent must always be confirmed
@@ -340,11 +352,14 @@ restart:
  */
 bool
 xfs_extent_busy_trim(
-	struct xfs_alloc_arg	*args,
+	struct xfs_group	*xg,
+	xfs_extlen_t		minlen,
+	xfs_extlen_t		maxlen,
 	xfs_agblock_t		*bno,
 	xfs_extlen_t		*len,
 	unsigned		*busy_gen)
 {
+	struct xfs_extent_busy_tree *eb = xg->xg_busy_extents;
 	xfs_agblock_t		fbno;
 	xfs_extlen_t		flen;
 	struct rb_node		*rbp;
@@ -352,11 +367,11 @@ xfs_extent_busy_trim(
 
 	ASSERT(*len > 0);
 
-	spin_lock(&args->pag->pagb_lock);
+	spin_lock(&eb->eb_lock);
 	fbno = *bno;
 	flen = *len;
-	rbp = args->pag->pagb_tree.rb_node;
-	while (rbp && flen >= args->minlen) {
+	rbp = eb->eb_tree.rb_node;
+	while (rbp && flen >= minlen) {
 		struct xfs_extent_busy *busyp =
 			rb_entry(rbp, struct xfs_extent_busy, rb_node);
 		xfs_agblock_t	fend = fbno + flen;
@@ -477,13 +492,13 @@ xfs_extent_busy_trim(
 			 * good chance subsequent allocations will be
 			 * contiguous.
 			 */
-			if (bbno - fbno >= args->maxlen) {
+			if (bbno - fbno >= maxlen) {
 				/* left candidate fits perfect */
 				fend = bbno;
-			} else if (fend - bend >= args->maxlen * 4) {
+			} else if (fend - bend >= maxlen * 4) {
 				/* right candidate has enough free space */
 				fbno = bend;
-			} else if (bbno - fbno >= args->minlen) {
+			} else if (bbno - fbno >= minlen) {
 				/* left candidate fits minimum requirement */
 				fend = bbno;
 			} else {
@@ -496,14 +511,13 @@ xfs_extent_busy_trim(
 out:
 
 	if (fbno != *bno || flen != *len) {
-		trace_xfs_extent_busy_trim(pag_group(args->pag), *bno, *len,
-					   fbno, flen);
+		trace_xfs_extent_busy_trim(xg, *bno, *len, fbno, flen);
 		*bno = fbno;
 		*len = flen;
-		*busy_gen = args->pag->pagb_gen;
+		*busy_gen = eb->eb_gen;
 		ret = true;
 	}
-	spin_unlock(&args->pag->pagb_lock);
+	spin_unlock(&eb->eb_lock);
 	return ret;
 fail:
 	/*
@@ -516,23 +530,24 @@ fail:
 
 static bool
 xfs_extent_busy_clear_one(
-	struct xfs_perag	*pag,
 	struct xfs_extent_busy	*busyp,
 	bool			do_discard)
 {
+	struct xfs_extent_busy_tree *eb = busyp->group->xg_busy_extents;
+
 	if (busyp->length) {
 		if (do_discard &&
 		    !(busyp->flags & XFS_EXTENT_BUSY_SKIP_DISCARD)) {
 			busyp->flags = XFS_EXTENT_BUSY_DISCARDED;
 			return false;
 		}
-		trace_xfs_extent_busy_clear(pag_group(pag), busyp->bno,
+		trace_xfs_extent_busy_clear(busyp->group, busyp->bno,
 				busyp->length);
-		rb_erase(&busyp->rb_node, &pag->pagb_tree);
+		rb_erase(&busyp->rb_node, &eb->eb_tree);
 	}
 
 	list_del_init(&busyp->list);
-	xfs_perag_put(busyp->pag);
+	xfs_group_put(busyp->group);
 	kfree(busyp);
 	return true;
 }
@@ -554,29 +569,30 @@ xfs_extent_busy_clear(
 		return;
 
 	do {
-		struct xfs_perag	*pag = xfs_perag_hold(busyp->pag);
+		struct xfs_group	*xg = xfs_group_hold(busyp->group);
+		struct xfs_extent_busy_tree *eb = xg->xg_busy_extents;
 		bool			wakeup = false;
 
-		spin_lock(&pag->pagb_lock);
+		spin_lock(&eb->eb_lock);
 		do {
 			next = list_next_entry(busyp, list);
-			if (xfs_extent_busy_clear_one(pag, busyp, do_discard))
+			if (xfs_extent_busy_clear_one(busyp, do_discard))
 				wakeup = true;
 			busyp = next;
 		} while (!list_entry_is_head(busyp, list, list) &&
-			 busyp->pag == pag);
+			 busyp->group == xg);
 
 		if (wakeup) {
-			pag->pagb_gen++;
-			wake_up_all(&pag->pagb_wait);
+			eb->eb_gen++;
+			wake_up_all(&eb->eb_wait);
 		}
-		spin_unlock(&pag->pagb_lock);
-		xfs_perag_put(pag);
+		spin_unlock(&eb->eb_lock);
+		xfs_group_put(xg);
 	} while (!list_entry_is_head(busyp, list, list));
 }
 
 /*
- * Flush out all busy extents for this AG.
+ * Flush out all busy extents for this group.
  *
  * If the current transaction is holding busy extents, the caller may not want
  * to wait for committed busy extents to resolve. If we are being told just to
@@ -592,10 +608,11 @@ xfs_extent_busy_clear(
 int
 xfs_extent_busy_flush(
 	struct xfs_trans	*tp,
-	struct xfs_perag	*pag,
+	struct xfs_group	*xg,
 	unsigned		busy_gen,
 	uint32_t		alloc_flags)
 {
+	struct xfs_extent_busy_tree *eb = xg->xg_busy_extents;
 	DEFINE_WAIT		(wait);
 	int			error;
 
@@ -608,7 +625,7 @@ xfs_extent_busy_flush(
 		if (alloc_flags & XFS_ALLOC_FLAG_TRYFLUSH)
 			return 0;
 
-		if (busy_gen != READ_ONCE(pag->pagb_gen))
+		if (busy_gen != READ_ONCE(eb->eb_gen))
 			return 0;
 
 		if (alloc_flags & XFS_ALLOC_FLAG_FREEING)
@@ -617,36 +634,44 @@ xfs_extent_busy_flush(
 
 	/* Wait for committed busy extents to resolve. */
 	do {
-		prepare_to_wait(&pag->pagb_wait, &wait, TASK_KILLABLE);
-		if  (busy_gen != READ_ONCE(pag->pagb_gen))
+		prepare_to_wait(&eb->eb_wait, &wait, TASK_KILLABLE);
+		if  (busy_gen != READ_ONCE(eb->eb_gen))
 			break;
 		schedule();
 	} while (1);
 
-	finish_wait(&pag->pagb_wait, &wait);
+	finish_wait(&eb->eb_wait, &wait);
 	return 0;
 }
 
+static void
+xfs_extent_busy_wait_group(
+	struct xfs_group	*xg)
+{
+	DEFINE_WAIT		(wait);
+	struct xfs_extent_busy_tree *eb = xg->xg_busy_extents;
+
+	do {
+		prepare_to_wait(&eb->eb_wait, &wait, TASK_KILLABLE);
+		if  (RB_EMPTY_ROOT(&eb->eb_tree))
+			break;
+		schedule();
+	} while (1);
+	finish_wait(&eb->eb_wait, &wait);
+}
+
 void
 xfs_extent_busy_wait_all(
 	struct xfs_mount	*mp)
 {
 	struct xfs_perag	*pag = NULL;
-	DEFINE_WAIT		(wait);
 
-	while ((pag = xfs_perag_next(mp, pag))) {
-		do {
-			prepare_to_wait(&pag->pagb_wait, &wait, TASK_KILLABLE);
-			if  (RB_EMPTY_ROOT(&pag->pagb_tree))
-				break;
-			schedule();
-		} while (1);
-		finish_wait(&pag->pagb_wait, &wait);
-	}
+	while ((pag = xfs_perag_next(mp, pag)))
+		xfs_extent_busy_wait_group(pag_group(pag));
 }
 
 /*
- * Callback for list_sort to sort busy extents by the AG they reside in.
+ * Callback for list_sort to sort busy extents by the group they reside in.
  */
 int
 xfs_extent_busy_ag_cmp(
@@ -660,23 +685,38 @@ xfs_extent_busy_ag_cmp(
 		container_of(l2, struct xfs_extent_busy, list);
 	s32 diff;
 
-	diff = pag_agno(b1->pag) - pag_agno(b2->pag);
+	diff = b1->group->xg_gno - b2->group->xg_gno;
 	if (!diff)
 		diff = b1->bno - b2->bno;
 	return diff;
 }
 
-/* Are there any busy extents in this AG? */
+/* Are there any busy extents in this group? */
 bool
 xfs_extent_busy_list_empty(
-	struct xfs_perag	*pag,
+	struct xfs_group	*xg,
 	unsigned		*busy_gen)
 {
+	struct xfs_extent_busy_tree *eb = xg->xg_busy_extents;
 	bool			res;
 
-	spin_lock(&pag->pagb_lock);
-	res = RB_EMPTY_ROOT(&pag->pagb_tree);
-	*busy_gen = READ_ONCE(pag->pagb_gen);
-	spin_unlock(&pag->pagb_lock);
+	spin_lock(&eb->eb_lock);
+	res = RB_EMPTY_ROOT(&eb->eb_tree);
+	*busy_gen = READ_ONCE(eb->eb_gen);
+	spin_unlock(&eb->eb_lock);
 	return res;
 }
+
+struct xfs_extent_busy_tree *
+xfs_extent_busy_alloc(void)
+{
+	struct xfs_extent_busy_tree *eb;
+
+	eb = kzalloc(sizeof(*eb), GFP_KERNEL);
+	if (!eb)
+		return NULL;
+	spin_lock_init(&eb->eb_lock);
+	init_waitqueue_head(&eb->eb_wait);
+	eb->eb_tree = RB_ROOT;
+	return eb;
+}
diff --git a/fs/xfs/xfs_extent_busy.h b/fs/xfs/xfs_extent_busy.h
index c803dcd124a6..f069b04e8ea1 100644
--- a/fs/xfs/xfs_extent_busy.h
+++ b/fs/xfs/xfs_extent_busy.h
@@ -8,19 +8,18 @@
 #ifndef __XFS_EXTENT_BUSY_H__
 #define	__XFS_EXTENT_BUSY_H__
 
+struct xfs_group;
 struct xfs_mount;
-struct xfs_perag;
 struct xfs_trans;
-struct xfs_alloc_arg;
 
 /*
- * Busy block/extent entry.  Indexed by a rbtree in perag to mark blocks that
- * have been freed but whose transactions aren't committed to disk yet.
+ * Busy block/extent entry.  Indexed by a rbtree in the group to mark blocks
+ * that have been freed but whose transactions aren't committed to disk yet.
  */
 struct xfs_extent_busy {
-	struct rb_node	rb_node;	/* ag by-bno indexed search tree */
+	struct rb_node	rb_node;	/* group by-bno indexed search tree */
 	struct list_head list;		/* transaction busy extent list */
-	struct xfs_perag *pag;
+	struct xfs_group *group;
 	xfs_agblock_t	bno;
 	xfs_extlen_t	length;
 	unsigned int	flags;
@@ -44,45 +43,29 @@ struct xfs_busy_extents {
 	void			*owner;
 };
 
-void
-xfs_extent_busy_insert(struct xfs_trans *tp, struct xfs_perag *pag,
-	xfs_agblock_t bno, xfs_extlen_t len, unsigned int flags);
-
-void
-xfs_extent_busy_insert_discard(struct xfs_perag *pag, xfs_agblock_t bno,
-	xfs_extlen_t len, struct list_head *busy_list);
-
-void
-xfs_extent_busy_clear(struct list_head *list, bool do_discard);
-
-int
-xfs_extent_busy_search(struct xfs_perag *pag, xfs_agblock_t bno,
+void xfs_extent_busy_insert(struct xfs_trans *tp, struct xfs_group *xg,
+		xfs_agblock_t bno, xfs_extlen_t len, unsigned int flags);
+void xfs_extent_busy_insert_discard(struct xfs_group *xg, xfs_agblock_t bno,
+		xfs_extlen_t len, struct list_head *busy_list);
+void xfs_extent_busy_clear(struct list_head *list, bool do_discard);
+int xfs_extent_busy_search(struct xfs_group *xg, xfs_agblock_t bno,
 		xfs_extlen_t len);
-
-void
-xfs_extent_busy_reuse(struct xfs_perag *pag, xfs_agblock_t fbno,
+void xfs_extent_busy_reuse(struct xfs_group *xg, xfs_agblock_t fbno,
 		xfs_extlen_t flen, bool userdata);
-
-bool
-xfs_extent_busy_trim(struct xfs_alloc_arg *args, xfs_agblock_t *bno,
-		xfs_extlen_t *len, unsigned *busy_gen);
-
-int
-xfs_extent_busy_flush(struct xfs_trans *tp, struct xfs_perag *pag,
+bool xfs_extent_busy_trim(struct xfs_group *xg, xfs_extlen_t minlen,
+		xfs_extlen_t maxlen, xfs_agblock_t *bno, xfs_extlen_t *len,
+		unsigned *busy_gen);
+int xfs_extent_busy_flush(struct xfs_trans *tp, struct xfs_group *xg,
 		unsigned busy_gen, uint32_t alloc_flags);
+void xfs_extent_busy_wait_all(struct xfs_mount *mp);
+bool xfs_extent_busy_list_empty(struct xfs_group *xg, unsigned int *busy_gen);
+struct xfs_extent_busy_tree *xfs_extent_busy_alloc(void);
 
-void
-xfs_extent_busy_wait_all(struct xfs_mount *mp);
-
-int
-xfs_extent_busy_ag_cmp(void *priv, const struct list_head *a,
-	const struct list_head *b);
-
+int xfs_extent_busy_ag_cmp(void *priv, const struct list_head *a,
+		const struct list_head *b);
 static inline void xfs_extent_busy_sort(struct list_head *list)
 {
 	list_sort(NULL, list, xfs_extent_busy_ag_cmp);
 }
 
-bool xfs_extent_busy_list_empty(struct xfs_perag *pag, unsigned int *busy_gen);
-
 #endif /* __XFS_EXTENT_BUSY_H__ */