Perag lookup rework

index 6946978..2de7876 100644
@@ -90,14 +90,13 @@ xfs_inode_ag_lookup(
 STATIC int
 xfs_inode_ag_walk(
 	struct xfs_mount	*mp,
-	xfs_agnumber_t		ag,
+	struct xfs_perag	*pag,
 	int			(*execute)(struct xfs_inode *ip,
 					   struct xfs_perag *pag, int flags),
 	int			flags,
 	int			tag,
 	int			exclusive)
 {
-	struct xfs_perag	*pag = &mp->m_perag[ag];
 	uint32_t		first_index;
 	int			last_error = 0;
 	int			skipped;

@@ -141,8 +140,6 @@ restart:
 		delay(1);
 		goto restart;
 	}
-
-	xfs_put_perag(mp, pag);
 	return last_error;
 }
 

@@ -160,10 +157,16 @@ xfs_inode_ag_iterator(
 	xfs_agnumber_t		ag;
 
 	for (ag = 0; ag < mp->m_sb.sb_agcount; ag++) {
-		if (!mp->m_perag[ag].pag_ici_init)
+		struct xfs_perag	*pag;
+
+		pag = xfs_perag_get(mp, ag);
+		if (!pag->pag_ici_init) {
+			xfs_perag_put(pag);
 			continue;
-		error = xfs_inode_ag_walk(mp, ag, execute, flags, tag,
+		}
+		error = xfs_inode_ag_walk(mp, pag, execute, flags, tag,
 						exclusive);
+		xfs_perag_put(pag);
 		if (error) {
 			last_error = error;
 			if (error == EFSCORRUPTED)

@@ -690,16 +693,17 @@ void
 xfs_inode_set_reclaim_tag(
 	xfs_inode_t	*ip)
 {
-	xfs_mount_t	*mp = ip->i_mount;
-	xfs_perag_t	*pag = xfs_get_perag(mp, ip->i_ino);
+	struct xfs_mount *mp = ip->i_mount;
+	struct xfs_perag *pag;
 
+	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
 	read_lock(&pag->pag_ici_lock);
 	spin_lock(&ip->i_flags_lock);
 	__xfs_inode_set_reclaim_tag(pag, ip);
 	__xfs_iflags_set(ip, XFS_IRECLAIMABLE);
 	spin_unlock(&ip->i_flags_lock);
 	read_unlock(&pag->pag_ici_lock);
-	xfs_put_perag(mp, pag);
+	xfs_perag_put(pag);
 }
 
 void

index 155e798..e281eb4 100644
@@ -374,7 +374,7 @@ xfs_iget(
 		return EINVAL;
 
 	/* get the perag structure and ensure that it's inode capable */
-	pag = xfs_get_perag(mp, ino);
+	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ino));
 	if (!pag->pagi_inodeok)
 		return EINVAL;
 	ASSERT(pag->pag_ici_init);

@@ -398,7 +398,7 @@ again:
 		if (error)
 			goto out_error_or_again;
 	}
-	xfs_put_perag(mp, pag);
+	xfs_perag_put(pag);
 
 	*ipp = ip;
 

@@ -417,7 +417,7 @@ out_error_or_again:
 		delay(1);
 		goto again;
 	}
-	xfs_put_perag(mp, pag);
+	xfs_perag_put(pag);
 	return error;
 }
 

@@ -488,12 +488,12 @@ xfs_ireclaim(
 	 * added to the tree assert that it's been there before to catch
 	 * problems with the inode life time early on.
 	 */
-	pag = xfs_get_perag(mp, ip->i_ino);
+	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
 	write_lock(&pag->pag_ici_lock);
 	if (!radix_tree_delete(&pag->pag_ici_root, agino))
 		ASSERT(0);
 	write_unlock(&pag->pag_ici_lock);
-	xfs_put_perag(mp, pag);
+	xfs_perag_put(pag);
 
 	/*
 	 * Here we do an (almost) spurious inode lock in order to coordinate

index ef77fd8..bd3d816 100644
@@ -1946,8 +1946,9 @@ xfs_ifree_cluster(
 	xfs_inode_t		*ip, **ip_found;
 	xfs_inode_log_item_t	*iip;
 	xfs_log_item_t		*lip;
-	xfs_perag_t		*pag = xfs_get_perag(mp, inum);
+	struct xfs_perag	*pag;
 
+	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, inum));
 	if (mp->m_sb.sb_blocksize >= XFS_INODE_CLUSTER_SIZE(mp)) {
 		blks_per_cluster = 1;
 		ninodes = mp->m_sb.sb_inopblock;

@@ -2088,7 +2089,7 @@ xfs_ifree_cluster(
 	}
 
 	kmem_free(ip_found);
-	xfs_put_perag(mp, pag);
+	xfs_perag_put(pag);
 }
 
 /*

@@ -2675,7 +2676,7 @@ xfs_iflush_cluster(
 	xfs_buf_t	*bp)
 {
 	xfs_mount_t		*mp = ip->i_mount;
-	xfs_perag_t		*pag = xfs_get_perag(mp, ip->i_ino);
+	struct xfs_perag	*pag;
 	unsigned long		first_index, mask;
 	unsigned long		inodes_per_cluster;
 	int			ilist_size;

@@ -2686,6 +2687,7 @@ xfs_iflush_cluster(
 	int			bufwasdelwri;
 	int			i;
 
+	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
 	ASSERT(pag->pagi_inodeok);
 	ASSERT(pag->pag_ici_init);
 

index 1df7e45..f8a68a2 100644
@@ -386,14 +386,14 @@ xfs_daddr_to_agbno(struct xfs_mount *mp, xfs_daddr_t d)
 /*
  * perag get/put wrappers for eventual ref counting
  */
-static inline xfs_perag_t *
-xfs_get_perag(struct xfs_mount *mp, xfs_ino_t ino)
+static inline struct xfs_perag *
+xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno)
 {
-	return &mp->m_perag[XFS_INO_TO_AGNO(mp, ino)];
+	return &mp->m_perag[agno];
 }
 
 static inline void
-xfs_put_perag(struct xfs_mount *mp, xfs_perag_t *pag)
+xfs_perag_put(struct xfs_perag *pag)
 {
 	/* nothing to see here, move along */
 }

index 275b1f4..84070f2 100644
@@ -1662,11 +1662,13 @@ xfs_free_ag_extent(
 		xfs_agf_t	*agf;
 		xfs_perag_t	*pag;		/* per allocation group data */
 
+		pag = xfs_perag_get(mp, agno);
+		pag->pagf_freeblks += len;
+		xfs_perag_put(pag);
+
 		agf = XFS_BUF_TO_AGF(agbp);
-		pag = &mp->m_perag[agno];
 		be32_add_cpu(&agf->agf_freeblks, len);
 		xfs_trans_agblocks_delta(tp, len);
-		pag->pagf_freeblks += len;
 		XFS_WANT_CORRUPTED_GOTO(
 			be32_to_cpu(agf->agf_freeblks) <=
 			be32_to_cpu(agf->agf_length),

@@ -1969,10 +1971,12 @@ xfs_alloc_get_freelist(
 	xfs_trans_brelse(tp, agflbp);
 	if (be32_to_cpu(agf->agf_flfirst) == XFS_AGFL_SIZE(mp))
 		agf->agf_flfirst = 0;
-	pag = &mp->m_perag[be32_to_cpu(agf->agf_seqno)];
+
+	pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno));
 	be32_add_cpu(&agf->agf_flcount, -1);
 	xfs_trans_agflist_delta(tp, -1);
 	pag->pagf_flcount--;
+	xfs_perag_put(pag);
 
 	logflags = XFS_AGF_FLFIRST | XFS_AGF_FLCOUNT;
 	if (btreeblk) {

@@ -2078,7 +2082,8 @@ xfs_alloc_put_freelist(
 	be32_add_cpu(&agf->agf_fllast, 1);
 	if (be32_to_cpu(agf->agf_fllast) == XFS_AGFL_SIZE(mp))
 		agf->agf_fllast = 0;
-	pag = &mp->m_perag[be32_to_cpu(agf->agf_seqno)];
+
+	pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno));
 	be32_add_cpu(&agf->agf_flcount, 1);
 	xfs_trans_agflist_delta(tp, 1);
 	pag->pagf_flcount++;

@@ -2089,6 +2094,7 @@ xfs_alloc_put_freelist(
 		pag->pagf_btreeblks--;
 		logflags |= XFS_AGF_BTREEBLKS;
 	}
+	xfs_perag_put(pag);
 
 	xfs_alloc_log_agf(tp, agbp, logflags);
 

@@ -2152,7 +2158,6 @@ xfs_read_agf(
 		xfs_trans_brelse(tp, *bpp);
 		return XFS_ERROR(EFSCORRUPTED);
 	}
-
 	XFS_BUF_SET_VTYPE_REF(*bpp, B_FS_AGF, XFS_AGF_REF);
 	return 0;
 }

@@ -2184,7 +2189,7 @@ xfs_alloc_read_agf(
 	ASSERT(!XFS_BUF_GETERROR(*bpp));
 
 	agf = XFS_BUF_TO_AGF(*bpp);
-	pag = &mp->m_perag[agno];
+	pag = xfs_perag_get(mp, agno);
 	if (!pag->pagf_init) {
 		pag->pagf_freeblks = be32_to_cpu(agf->agf_freeblks);
 		pag->pagf_btreeblks = be32_to_cpu(agf->agf_btreeblks);

@@ -2211,6 +2216,7 @@ xfs_alloc_read_agf(
 		       be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]));
 	}
 #endif
+	xfs_perag_put(pag);
 	return 0;
 }
 

@@ -2271,7 +2277,7 @@ xfs_alloc_vextent(
 		 */
 		args->agno = XFS_FSB_TO_AGNO(mp, args->fsbno);
 		down_read(&mp->m_peraglock);
-		args->pag = &mp->m_perag[args->agno];
+		args->pag = xfs_perag_get(mp, args->agno);
 		args->minleft = 0;
 		error = xfs_alloc_fix_freelist(args, 0);
 		args->minleft = minleft;

@@ -2341,7 +2347,7 @@ xfs_alloc_vextent(
 		 */
 		down_read(&mp->m_peraglock);
 		for (;;) {
-			args->pag = &mp->m_perag[args->agno];
+			args->pag = xfs_perag_get(mp, args->agno);
 			if (no_min) args->minleft = 0;
 			error = xfs_alloc_fix_freelist(args, flags);
 			args->minleft = minleft;

@@ -2400,6 +2406,7 @@ xfs_alloc_vextent(
 					}
 				}
 			}
+			xfs_perag_put(args->pag);
 		}
 		up_read(&mp->m_peraglock);
 		if (bump_rotor || (type == XFS_ALLOCTYPE_ANY_AG)) {

@@ -2427,8 +2434,10 @@ xfs_alloc_vextent(
 			args->len);
 #endif
 	}
+	xfs_perag_put(args->pag);
 	return 0;
 error0:
+	xfs_perag_put(args->pag);
 	up_read(&mp->m_peraglock);
 	return error;
 }

@@ -2455,7 +2464,7 @@ xfs_free_extent(
 	ASSERT(args.agno < args.mp->m_sb.sb_agcount);
 	args.agbno = XFS_FSB_TO_AGBNO(args.mp, bno);
 	down_read(&args.mp->m_peraglock);
-	args.pag = &args.mp->m_perag[args.agno];
+	args.pag = xfs_perag_get(args.mp, args.agno);
 	if ((error = xfs_alloc_fix_freelist(&args, XFS_ALLOC_FLAG_FREEING)))
 		goto error0;
 #ifdef DEBUG

@@ -2465,6 +2474,7 @@ xfs_free_extent(
 #endif
 	error = xfs_free_ag_extent(tp, args.agbp, args.agno, args.agbno, len, 0);
 error0:
+	xfs_perag_put(args.pag);
 	up_read(&args.mp->m_peraglock);
 	return error;
 }

@@ -2486,15 +2496,15 @@ xfs_alloc_mark_busy(xfs_trans_t *tp,
 		    xfs_agblock_t bno,
 		    xfs_extlen_t len)
 {
-	xfs_mount_t		*mp;
 	xfs_perag_busy_t	*bsy;
+	struct xfs_perag	*pag;
 	int			n;
 
-	mp = tp->t_mountp;
-	spin_lock(&mp->m_perag[agno].pagb_lock);
+	pag = xfs_perag_get(tp->t_mountp, agno);
+	spin_lock(&pag->pagb_lock);
 
 	/* search pagb_list for an open slot */
-	for (bsy = mp->m_perag[agno].pagb_list, n = 0;
+	for (bsy = pag->pagb_list, n = 0;
 	     n < XFS_PAGB_NUM_SLOTS;
 	     bsy++, n++) {
 		if (bsy->busy_tp == NULL) {

@@ -2502,11 +2512,11 @@ xfs_alloc_mark_busy(xfs_trans_t *tp,
 		}
 	}
 
-	trace_xfs_alloc_busy(mp, agno, bno, len, n);
+	trace_xfs_alloc_busy(tp->t_mountp, agno, bno, len, n);
 
 	if (n < XFS_PAGB_NUM_SLOTS) {
-		bsy = &mp->m_perag[agno].pagb_list[n];
-		mp->m_perag[agno].pagb_count++;
+		bsy = &pag->pagb_list[n];
+		pag->pagb_count++;
 		bsy->busy_start = bno;
 		bsy->busy_length = len;
 		bsy->busy_tp = tp;

@@ -2521,7 +2531,8 @@ xfs_alloc_mark_busy(xfs_trans_t *tp,
 		xfs_trans_set_sync(tp);
 	}
 
-	spin_unlock(&mp->m_perag[agno].pagb_lock);
+	spin_unlock(&pag->pagb_lock);
+	xfs_perag_put(pag);
 }
 
 void

@@ -2529,24 +2540,23 @@ xfs_alloc_clear_busy(xfs_trans_t *tp,
 		     xfs_agnumber_t agno,
 		     int idx)
 {
-	xfs_mount_t		*mp;
+	struct xfs_perag	*pag;
 	xfs_perag_busy_t	*list;
 
-	mp = tp->t_mountp;
-
-	spin_lock(&mp->m_perag[agno].pagb_lock);
-	list = mp->m_perag[agno].pagb_list;
-
 	ASSERT(idx < XFS_PAGB_NUM_SLOTS);
+	pag = xfs_perag_get(tp->t_mountp, agno);
+	spin_lock(&pag->pagb_lock);
+	list = pag->pagb_list;
 
-	trace_xfs_alloc_unbusy(mp, agno, idx, list[idx].busy_tp == tp);
+	trace_xfs_alloc_unbusy(tp->t_mountp, agno, idx, list[idx].busy_tp == tp);
 
 	if (list[idx].busy_tp == tp) {
 		list[idx].busy_tp = NULL;
-		mp->m_perag[agno].pagb_count--;
+		pag->pagb_count--;
 	}
 
-	spin_unlock(&mp->m_perag[agno].pagb_lock);
+	spin_unlock(&pag->pagb_lock);
+	xfs_perag_put(pag);
 }
 
 

@@ -2560,17 +2570,15 @@ xfs_alloc_search_busy(xfs_trans_t *tp,
 		    xfs_agblock_t bno,
 		    xfs_extlen_t len)
 {
-	xfs_mount_t		*mp;
+	struct xfs_perag	*pag;
 	xfs_perag_busy_t	*bsy;
 	xfs_agblock_t		uend, bend;
 	xfs_lsn_t		lsn = 0;
 	int			cnt;
 
-	mp = tp->t_mountp;
-
-	spin_lock(&mp->m_perag[agno].pagb_lock);
-
-	uend = bno + len - 1;
+	pag = xfs_perag_get(tp->t_mountp, agno);
+	spin_lock(&pag->pagb_lock);
+	cnt = pag->pagb_count;
 
 	/*
 	 * search pagb_list for this slot, skipping open slots. We have to

@@ -2578,8 +2586,9 @@ xfs_alloc_search_busy(xfs_trans_t *tp,
 	 * we have to get the most recent LSN for the log force to push out
 	 * all the transactions that span the range.
 	 */
-	for (cnt = 0; cnt < mp->m_perag[agno].pagb_count; cnt++) {
-		bsy = &mp->m_perag[agno].pagb_list[cnt];
+	uend = bno + len - 1;
+	for (cnt = 0; cnt < pag->pagb_count; cnt++) {
+		bsy = &pag->pagb_list[cnt];
 		if (!bsy->busy_tp)
 			continue;
 

@@ -2591,7 +2600,8 @@ xfs_alloc_search_busy(xfs_trans_t *tp,
 		if (XFS_LSN_CMP(bsy->busy_tp->t_commit_lsn, lsn) > 0)
 			lsn = bsy->busy_tp->t_commit_lsn;
 	}
-	spin_unlock(&mp->m_perag[agno].pagb_lock);
+	spin_unlock(&pag->pagb_lock);
+	xfs_perag_put(pag);
 	trace_xfs_alloc_busysearch(tp->t_mountp, agno, bno, len, lsn);
 
 	/*

@@ -2599,5 +2609,5 @@ xfs_alloc_search_busy(xfs_trans_t *tp,
 	 * transaction that freed the block
 	 */
 	if (lsn)
-		xfs_log_force(mp, lsn, XFS_LOG_FORCE|XFS_LOG_SYNC);
+		xfs_log_force(tp->t_mountp, lsn, XFS_LOG_FORCE|XFS_LOG_SYNC);
 }

index adbd914..b726e10 100644
@@ -61,12 +61,14 @@ xfs_allocbt_set_root(
 	struct xfs_agf		*agf = XFS_BUF_TO_AGF(agbp);
 	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);
 
 	ASSERT(ptr->s != 0);
 
 	agf->agf_roots[btnum] = ptr->s;
 	be32_add_cpu(&agf->agf_levels[btnum], inc);
-	cur->bc_mp->m_perag[seqno].pagf_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);
 }

@@ -150,6 +152,7 @@ xfs_allocbt_update_lastrec(
 {
 	struct xfs_agf		*agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp);
 	xfs_agnumber_t		seqno = be32_to_cpu(agf->agf_seqno);
+	struct xfs_perag	*pag;
 	__be32			len;
 	int			numrecs;
 

@@ -193,7 +196,9 @@ xfs_allocbt_update_lastrec(
 	}
 
 	agf->agf_longest = len;
-	cur->bc_mp->m_perag[seqno].pagf_longest = be32_to_cpu(len);
+	pag = xfs_perag_get(cur->bc_mp, seqno);
+	pag->pagf_longest = be32_to_cpu(len);
+	xfs_perag_put(pag);
 	xfs_alloc_log_agf(cur->bc_tp, cur->bc_private.a.agbp, XFS_AGF_LONGEST);
 }
 

index a631e14..e61f2aa 100644
@@ -140,6 +140,7 @@ _xfs_filestream_pick_ag(
 	int		flags,
 	xfs_extlen_t	minlen)
 {
+	int		streams, max_streams;
 	int		err, trylock, nscan;
 	xfs_extlen_t	longest, free, minfree, maxfree = 0;
 	xfs_agnumber_t	ag, max_ag = NULLAGNUMBER;

@@ -155,15 +156,15 @@ _xfs_filestream_pick_ag(
 	trylock = XFS_ALLOC_FLAG_TRYLOCK;
 
 	for (nscan = 0; 1; nscan++) {
-
-		TRACE_AG_SCAN(mp, ag, xfs_filestream_peek_ag(mp, ag));
-
-		pag = mp->m_perag + ag;
+		pag = xfs_perag_get(mp, ag);
+		TRACE_AG_SCAN(mp, ag, atomic_read(&pag->pagf_fstrms));
 
 		if (!pag->pagf_init) {
 			err = xfs_alloc_pagf_init(mp, NULL, ag, trylock);
-			if (err && !trylock)
+			if (err && !trylock) {
+				xfs_perag_put(pag);
 				return err;
+			}
 		}
 
 		/* Might fail sometimes during the 1st pass with trylock set. */

@@ -173,6 +174,7 @@ _xfs_filestream_pick_ag(
 		/* Keep track of the AG with the most free blocks. */
 		if (pag->pagf_freeblks > maxfree) {
 			maxfree = pag->pagf_freeblks;
+			max_streams = atomic_read(&pag->pagf_fstrms);
 			max_ag = ag;
 		}
 

@@ -195,6 +197,8 @@ _xfs_filestream_pick_ag(
 
 			/* Break out, retaining the reference on the AG. */
 			free = pag->pagf_freeblks;
+			streams = atomic_read(&pag->pagf_fstrms);
+			xfs_perag_put(pag);
 			*agp = ag;
 			break;
 		}

@@ -202,6 +206,7 @@ _xfs_filestream_pick_ag(
 		/* Drop the reference on this AG, it's not usable. */
 		xfs_filestream_put_ag(mp, ag);
 next_ag:
+		xfs_perag_put(pag);
 		/* Move to the next AG, wrapping to AG 0 if necessary. */
 		if (++ag >= mp->m_sb.sb_agcount)
 			ag = 0;

@@ -229,6 +234,7 @@ next_ag:
 		if (max_ag != NULLAGNUMBER) {
 			xfs_filestream_get_ag(mp, max_ag);
 			TRACE_AG_PICK1(mp, max_ag, maxfree);
+			streams = max_streams;
 			free = maxfree;
 			*agp = max_ag;
 			break;

@@ -240,8 +246,7 @@ next_ag:
 		return 0;
 	}
 
-	TRACE_AG_PICK2(mp, startag, *agp, xfs_filestream_peek_ag(mp, *agp),
-			free, nscan, flags);
+	TRACE_AG_PICK2(mp, startag, *agp, streams, free, nscan, flags);
 
 	return 0;
 }

index 4aba67c..58378b2 100644
@@ -79,12 +79,21 @@ extern ktrace_t *xfs_filestreams_trace_buf;
  * the cache that reference per-ag array elements that have since been
  * reallocated.
  */
+/*
+ * xfs_filestream_peek_ag is only used in tracing code
+ */
 static inline int
 xfs_filestream_peek_ag(
 	xfs_mount_t	*mp,
 	xfs_agnumber_t	agno)
 {
-	return atomic_read(&mp->m_perag[agno].pagf_fstrms);
+	struct xfs_perag *pag;
+	int		ret;
+
+	pag = xfs_perag_get(mp, agno);
+	ret = atomic_read(&pag->pagf_fstrms);
+	xfs_perag_put(pag);
+	return ret;
 }
 
 static inline int

@@ -92,7 +101,13 @@ xfs_filestream_get_ag(
 	xfs_mount_t	*mp,
 	xfs_agnumber_t	agno)
 {
-	return atomic_inc_return(&mp->m_perag[agno].pagf_fstrms);
+	struct xfs_perag *pag;
+	int		ret;
+
+	pag = xfs_perag_get(mp, agno);
+	ret = atomic_inc_return(&pag->pagf_fstrms);
+	xfs_perag_put(pag);
+	return ret;
 }
 
 static inline int

@@ -100,7 +115,13 @@ xfs_filestream_put_ag(
 	xfs_mount_t	*mp,
 	xfs_agnumber_t	agno)
 {
-	return atomic_dec_return(&mp->m_perag[agno].pagf_fstrms);
+	struct xfs_perag *pag;
+	int		ret;
+
+	pag = xfs_perag_get(mp, agno);
+	ret = atomic_dec_return(&pag->pagf_fstrms);
+	xfs_perag_put(pag);
+	return ret;
 }
 
 /* allocation selection flags */

index 98251cd..a9b95d9 100644
@@ -2630,11 +2630,12 @@ xfs_bmap_btalloc(
 			startag = ag = 0;
 		notinit = 0;
 		down_read(&mp->m_peraglock);
+		pag = xfs_perag_get(mp, ag);
 		while (blen < ap->alen) {
-			pag = &mp->m_perag[ag];
 			if (!pag->pagf_init &&
 			    (error = xfs_alloc_pagf_init(mp, args.tp,
 				    ag, XFS_ALLOC_FLAG_TRYLOCK))) {
+				xfs_perag_put(pag);
 				up_read(&mp->m_peraglock);
 				return error;
 			}

@@ -2667,6 +2668,7 @@ xfs_bmap_btalloc(
 						break;
 
 					error = xfs_filestream_new_ag(ap, &ag);
+					xfs_perag_put(pag);
 					if (error) {
 						up_read(&mp->m_peraglock);
 						return error;

@@ -2674,6 +2676,7 @@ xfs_bmap_btalloc(
 
 					/* loop again to set 'blen'*/
 					startag = NULLAGNUMBER;
+					pag = xfs_perag_get(mp, ag);
 					continue;
 				}
 			}

@@ -2681,7 +2684,10 @@ xfs_bmap_btalloc(
 				ag = 0;
 			if (ag == startag)
 				break;
+			xfs_perag_put(pag);
+			pag = xfs_perag_get(mp, ag);
 		}
+		xfs_perag_put(pag);
 		up_read(&mp->m_peraglock);
 		/*
 		 * Since the above loop did a BUF_TRYLOCK, it is

index cb907ba..884ee13 100644
@@ -253,6 +253,7 @@ xfs_ialloc_ag_alloc(
 	xfs_agino_t	thisino;	/* current inode number, for loop */
 	int		isaligned = 0;	/* inode allocation at stripe unit */
 					/* boundary */
+	struct xfs_perag *pag;
 
 	args.tp = tp;
 	args.mp = tp->t_mountp;

@@ -383,7 +384,9 @@ xfs_ialloc_ag_alloc(
 	be32_add_cpu(&agi->agi_count, newlen);
 	be32_add_cpu(&agi->agi_freecount, newlen);
 	down_read(&args.mp->m_peraglock);
-	args.mp->m_perag[agno].pagi_freecount += newlen;
+	pag = xfs_perag_get(args.mp, agno);
+	pag->pagi_freecount += newlen;
+	xfs_perag_put(pag);
 	up_read(&args.mp->m_peraglock);
 	agi->agi_newino = cpu_to_be32(newino);
 

@@ -488,7 +491,7 @@ xfs_ialloc_ag_select(
 	flags = XFS_ALLOC_FLAG_TRYLOCK;
 	down_read(&mp->m_peraglock);
 	for (;;) {
-		pag = &mp->m_perag[agno];
+		pag = xfs_perag_get(mp, agno);
 		if (!pag->pagi_init) {
 			if (xfs_ialloc_read_agi(mp, tp, agno, &agbp)) {
 				agbp = NULL;

@@ -527,6 +530,7 @@ xfs_ialloc_ag_select(
 					agbp = NULL;
 					goto nextag;
 				}
+				xfs_perag_put(pag);
 				up_read(&mp->m_peraglock);
 				return agbp;
 			}

@@ -535,6 +539,7 @@ unlock_nextag:
 		if (agbp)
 			xfs_trans_brelse(tp, agbp);
 nextag:
+		xfs_perag_put(pag);
 		/*
 		 * No point in iterating over the rest, if we're shutting
 		 * down.

@@ -672,6 +677,7 @@ xfs_dialloc(
 	xfs_agnumber_t	tagno;		/* testing allocation group number */
 	xfs_btree_cur_t	*tcur;		/* temp cursor */
 	xfs_inobt_rec_incore_t trec;	/* temp inode allocation record */
+	struct xfs_perag *pag;
 
 
 	if (*IO_agbp == NULL) {

@@ -772,11 +778,14 @@ nextag:
 			return noroom ? ENOSPC : 0;
 		}
 		down_read(&mp->m_peraglock);
-		if (mp->m_perag[tagno].pagi_inodeok == 0) {
+		pag = xfs_perag_get(mp, tagno);
+		if (pag->pagi_inodeok == 0) {
+			xfs_perag_put(pag);
 			up_read(&mp->m_peraglock);
 			goto nextag;
 		}
 		error = xfs_ialloc_read_agi(mp, tp, tagno, &agbp);
+		xfs_perag_put(pag);
 		up_read(&mp->m_peraglock);
 		if (error)
 			goto nextag;

@@ -790,6 +799,7 @@ nextag:
 	 */
 	agno = tagno;
 	*IO_agbp = NULL;
+	pag = xfs_perag_get(mp, agno);
 
  restart_pagno:
 	cur = xfs_inobt_init_cursor(mp, tp, agbp, be32_to_cpu(agi->agi_seqno));

@@ -808,7 +818,6 @@ nextag:
 	 * If in the same AG as the parent, try to get near the parent.
 	 */
 	if (pagno == agno) {
-		xfs_perag_t	*pag = &mp->m_perag[agno];
 		int		doneleft;	/* done, to the left */
 		int		doneright;	/* done, to the right */
 		int		searchdistance = 10;

@@ -1007,7 +1016,7 @@ alloc_inode:
 	be32_add_cpu(&agi->agi_freecount, -1);
 	xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
 	down_read(&mp->m_peraglock);
-	mp->m_perag[tagno].pagi_freecount--;
+	pag->pagi_freecount--;
 	up_read(&mp->m_peraglock);
 
 	error = xfs_check_agi_freecount(cur, agi);

@@ -1016,12 +1025,14 @@ alloc_inode:
 
 	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;
 }
 

@@ -1052,6 +1063,7 @@ xfs_difree(
 	xfs_mount_t	*mp;	/* mount structure for filesystem */
 	int		off;	/* offset of inode in inode chunk */
 	xfs_inobt_rec_incore_t rec;	/* btree record */
+	struct xfs_perag *pag;
 
 	mp = tp->t_mountp;
 

@@ -1158,7 +1170,9 @@ xfs_difree(
 		be32_add_cpu(&agi->agi_freecount, -(ilen - 1));
 		xfs_ialloc_log_agi(tp, agbp, XFS_AGI_COUNT | XFS_AGI_FREECOUNT);
 		down_read(&mp->m_peraglock);
-		mp->m_perag[agno].pagi_freecount -= ilen - 1;
+		pag = xfs_perag_get(mp, agno);
+		pag->pagi_freecount -= ilen - 1;
+		xfs_perag_put(pag);
 		up_read(&mp->m_peraglock);
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_ICOUNT, -ilen);
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -(ilen - 1));

@@ -1189,7 +1203,9 @@ xfs_difree(
 		be32_add_cpu(&agi->agi_freecount, 1);
 		xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
 		down_read(&mp->m_peraglock);
-		mp->m_perag[agno].pagi_freecount++;
+		pag = xfs_perag_get(mp, agno);
+		pag->pagi_freecount++;
+		xfs_perag_put(pag);
 		up_read(&mp->m_peraglock);
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, 1);
 	}

@@ -1379,7 +1395,6 @@ xfs_imap(
 			XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks));
 		return XFS_ERROR(EINVAL);
 	}
-
 	return 0;
 }
 

@@ -1523,8 +1538,7 @@ xfs_ialloc_read_agi(
 		return error;
 
 	agi = XFS_BUF_TO_AGI(*bpp);
-	pag = &mp->m_perag[agno];
-
+	pag = xfs_perag_get(mp, agno);
 	if (!pag->pagi_init) {
 		pag->pagi_freecount = be32_to_cpu(agi->agi_freecount);
 		pag->pagi_count = be32_to_cpu(agi->agi_count);

@@ -1537,6 +1551,7 @@ xfs_ialloc_read_agi(
 	 */
 	ASSERT(pag->pagi_freecount == be32_to_cpu(agi->agi_freecount) ||
 		XFS_FORCED_SHUTDOWN(mp));
+	xfs_perag_put(pag);
 	return 0;
 }
 

index bd3d816..0317b00 100644
@@ -2695,7 +2695,7 @@ xfs_iflush_cluster(
 	ilist_size = inodes_per_cluster * sizeof(xfs_inode_t *);
 	ilist = kmem_alloc(ilist_size, KM_MAYFAIL|KM_NOFS);
 	if (!ilist)
-		return 0;
+		goto out_put;
 
 	mask = ~(((XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_inodelog)) - 1);
 	first_index = XFS_INO_TO_AGINO(mp, ip->i_ino) & mask;

@@ -2764,6 +2764,8 @@ xfs_iflush_cluster(
 out_free:
 	read_unlock(&pag->pag_ici_lock);
 	kmem_free(ilist);
+out_put:
+	xfs_perag_put(pag);
 	return 0;
 
 

@@ -2807,6 +2809,7 @@ cluster_corrupt_out:
 	 */
 	xfs_iflush_abort(iq);
 	kmem_free(ilist);
+	xfs_perag_put(pag);
 	return XFS_ERROR(EFSCORRUPTED);
 }
 

index eb403b4..9055b60 100644
@@ -438,18 +438,20 @@ xfs_initialize_perag(
 			}
 
 			/* This ag is preferred for inodes */
-			pag = &mp->m_perag[index];
+			pag = xfs_perag_get(mp, index);
 			pag->pagi_inodeok = 1;
 			if (index < max_metadata)
 				pag->pagf_metadata = 1;
 			xfs_initialize_perag_icache(pag);
+			xfs_perag_put(pag);
 		}
 	} else {
 		/* Setup default behavior for smaller filesystems */
 		for (index = 0; index < agcount; index++) {
-			pag = &mp->m_perag[index];
+			pag = xfs_perag_get(mp, index);
 			pag->pagi_inodeok = 1;
 			xfs_initialize_perag_icache(pag);
+			xfs_perag_put(pag);
 		}
 	}
 	return index;

@@ -731,12 +733,13 @@ xfs_initialize_perag_data(xfs_mount_t *mp, xfs_agnumber_t agcount)
 		error = xfs_ialloc_pagi_init(mp, NULL, index);
 		if (error)
 			return error;
-		pag = &mp->m_perag[index];
+		pag = xfs_perag_get(mp, index);
 		ifree += pag->pagi_freecount;
 		ialloc += pag->pagi_count;
 		bfree += pag->pagf_freeblks;
 		bfreelst += pag->pagf_flcount;
 		btree += pag->pagf_btreeblks;
+		xfs_perag_put(pag);
 	}
 	/*
 	 * Overwrite incore superblock counters with just-read data

index 84070f2..4d66bb7 100644
@@ -2276,7 +2276,6 @@ xfs_alloc_vextent(
 		 * These three force us into a single a.g.
 		 */
 		args->agno = XFS_FSB_TO_AGNO(mp, args->fsbno);
-		down_read(&mp->m_peraglock);
 		args->pag = xfs_perag_get(mp, args->agno);
 		args->minleft = 0;
 		error = xfs_alloc_fix_freelist(args, 0);

@@ -2286,14 +2285,12 @@ xfs_alloc_vextent(
 			goto error0;
 		}
 		if (!args->agbp) {
-			up_read(&mp->m_peraglock);
 			trace_xfs_alloc_vextent_noagbp(args);
 			break;
 		}
 		args->agbno = XFS_FSB_TO_AGBNO(mp, args->fsbno);
 		if ((error = xfs_alloc_ag_vextent(args)))
 			goto error0;
-		up_read(&mp->m_peraglock);
 		break;
 	case XFS_ALLOCTYPE_START_BNO:
 		/*

@@ -2345,7 +2342,6 @@ xfs_alloc_vextent(
 		 * Loop over allocation groups twice; first time with
 		 * trylock set, second time without.
 		 */
-		down_read(&mp->m_peraglock);
 		for (;;) {
 			args->pag = xfs_perag_get(mp, args->agno);
 			if (no_min) args->minleft = 0;

@@ -2408,7 +2404,6 @@ xfs_alloc_vextent(
 			}
 			xfs_perag_put(args->pag);
 		}
-		up_read(&mp->m_peraglock);
 		if (bump_rotor || (type == XFS_ALLOCTYPE_ANY_AG)) {
 			if (args->agno == sagno)
 				mp->m_agfrotor = (mp->m_agfrotor + 1) %

@@ -2438,7 +2433,6 @@ xfs_alloc_vextent(
 	return 0;
 error0:
 	xfs_perag_put(args->pag);
-	up_read(&mp->m_peraglock);
 	return error;
 }
 

@@ -2463,7 +2457,6 @@ xfs_free_extent(
 	args.agno = XFS_FSB_TO_AGNO(args.mp, bno);
 	ASSERT(args.agno < args.mp->m_sb.sb_agcount);
 	args.agbno = XFS_FSB_TO_AGBNO(args.mp, bno);
-	down_read(&args.mp->m_peraglock);
 	args.pag = xfs_perag_get(args.mp, args.agno);
 	if ((error = xfs_alloc_fix_freelist(&args, XFS_ALLOC_FLAG_FREEING)))
 		goto error0;

@@ -2475,7 +2468,6 @@ xfs_free_extent(
 	error = xfs_free_ag_extent(tp, args.agbp, args.agno, args.agbno, len, 0);
 error0:
 	xfs_perag_put(args.pag);
-	up_read(&args.mp->m_peraglock);
 	return error;
 }
 

index a9b95d9..7c6d9ac 100644
@@ -2629,14 +2629,12 @@ xfs_bmap_btalloc(
 		if (startag == NULLAGNUMBER)
 			startag = ag = 0;
 		notinit = 0;
-		down_read(&mp->m_peraglock);
 		pag = xfs_perag_get(mp, ag);
 		while (blen < ap->alen) {
 			if (!pag->pagf_init &&
 			    (error = xfs_alloc_pagf_init(mp, args.tp,
 				    ag, XFS_ALLOC_FLAG_TRYLOCK))) {
 				xfs_perag_put(pag);
-				up_read(&mp->m_peraglock);
 				return error;
 			}
 			/*

@@ -2669,10 +2667,8 @@ xfs_bmap_btalloc(
 
 					error = xfs_filestream_new_ag(ap, &ag);
 					xfs_perag_put(pag);
-					if (error) {
-						up_read(&mp->m_peraglock);
+					if (error)
 						return error;
-					}
 
 					/* loop again to set 'blen'*/
 					startag = NULLAGNUMBER;

@@ -2688,7 +2684,6 @@ xfs_bmap_btalloc(
 			pag = xfs_perag_get(mp, ag);
 		}
 		xfs_perag_put(pag);
-		up_read(&mp->m_peraglock);
 		/*
 		 * Since the above loop did a BUF_TRYLOCK, it is
 		 * possible that there is space for this request.

index e61f2aa..914d00d 100644
@@ -253,8 +253,7 @@ next_ag:
 
 /*
  * Set the allocation group number for a file or a directory, updating inode
- * references and per-AG references as appropriate.  Must be called with the
- * m_peraglock held in read mode.
+ * references and per-AG references as appropriate.
  */
 static int
 _xfs_filestream_update_ag(

@@ -456,10 +455,10 @@ xfs_filestream_unmount(
 }
 
 /*
- * If the mount point's m_perag array is going to be reallocated, all
+ * If the mount point's m_perag tree is going to be modified, all
  * outstanding cache entries must be flushed to avoid accessing reference count
  * addresses that have been freed.  The call to xfs_filestream_flush() must be
- * made inside the block that holds the m_peraglock in write mode to do the
+ * made inside the block that holds the m_perag_lock in write mode to do the
  * reallocation.
  */
 void

@@ -531,7 +530,6 @@ xfs_filestream_associate(
 
 	mp = pip->i_mount;
 	cache = mp->m_filestream;
-	down_read(&mp->m_peraglock);
 
 	/*
 	 * We have a problem, Houston.

@@ -548,10 +546,8 @@ xfs_filestream_associate(
 	 *
 	 * So, if we can't get the iolock without sleeping then just give up
 	 */
-	if (!xfs_ilock_nowait(pip, XFS_IOLOCK_EXCL)) {
-		up_read(&mp->m_peraglock);
+	if (!xfs_ilock_nowait(pip, XFS_IOLOCK_EXCL))
 		return 1;
-	}
 
 	/* If the parent directory is already in the cache, use its AG. */
 	item = xfs_mru_cache_lookup(cache, pip->i_ino);

@@ -606,7 +602,6 @@ exit_did_pick:
 
 exit:
 	xfs_iunlock(pip, XFS_IOLOCK_EXCL);
-	up_read(&mp->m_peraglock);
 	return -err;
 }
 

75 lines not on this page · raw message

index 884ee13..52c9d00 100644
@@ -383,11 +383,9 @@ xfs_ialloc_ag_alloc(
 	newino = XFS_OFFBNO_TO_AGINO(args.mp, args.agbno, 0);
 	be32_add_cpu(&agi->agi_count, newlen);
 	be32_add_cpu(&agi->agi_freecount, newlen);
-	down_read(&args.mp->m_peraglock);
 	pag = xfs_perag_get(args.mp, agno);
 	pag->pagi_freecount += newlen;
 	xfs_perag_put(pag);
-	up_read(&args.mp->m_peraglock);
 	agi->agi_newino = cpu_to_be32(newino);
 
 	/*

@@ -489,7 +487,6 @@ xfs_ialloc_ag_select(
 	 */
 	agno = pagno;
 	flags = XFS_ALLOC_FLAG_TRYLOCK;
-	down_read(&mp->m_peraglock);
 	for (;;) {
 		pag = xfs_perag_get(mp, agno);
 		if (!pag->pagi_init) {

@@ -531,7 +528,6 @@ xfs_ialloc_ag_select(
 					goto nextag;
 				}
 				xfs_perag_put(pag);
-				up_read(&mp->m_peraglock);
 				return agbp;
 			}
 		}

@@ -544,18 +540,14 @@ nextag:
 		 * No point in iterating over the rest, if we're shutting
 		 * down.
 		 */
-		if (XFS_FORCED_SHUTDOWN(mp)) {
-			up_read(&mp->m_peraglock);
+		if (XFS_FORCED_SHUTDOWN(mp))
 			return NULL;
-		}
 		agno++;
 		if (agno >= agcount)
 			agno = 0;
 		if (agno == pagno) {
-			if (flags == 0) {
-				up_read(&mp->m_peraglock);
+			if (flags == 0)
 				return NULL;
-			}
 			flags = 0;
 		}
 	}

@@ -777,16 +769,13 @@ nextag:
 			*inop = NULLFSINO;
 			return noroom ? ENOSPC : 0;
 		}
-		down_read(&mp->m_peraglock);
 		pag = xfs_perag_get(mp, tagno);
 		if (pag->pagi_inodeok == 0) {
 			xfs_perag_put(pag);
-			up_read(&mp->m_peraglock);
 			goto nextag;
 		}
 		error = xfs_ialloc_read_agi(mp, tp, tagno, &agbp);
 		xfs_perag_put(pag);
-		up_read(&mp->m_peraglock);
 		if (error)
 			goto nextag;
 		agi = XFS_BUF_TO_AGI(agbp);

@@ -1015,9 +1004,7 @@ alloc_inode:
 		goto error0;
 	be32_add_cpu(&agi->agi_freecount, -1);
 	xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
-	down_read(&mp->m_peraglock);
 	pag->pagi_freecount--;
-	up_read(&mp->m_peraglock);
 
 	error = xfs_check_agi_freecount(cur, agi);
 	if (error)

@@ -1100,9 +1087,7 @@ xfs_difree(
 	/*
 	 * Get the allocation group header.
 	 */
-	down_read(&mp->m_peraglock);
 	error = xfs_ialloc_read_agi(mp, tp, agno, &agbp);
-	up_read(&mp->m_peraglock);
 	if (error) {
 		cmn_err(CE_WARN,
 			"xfs_difree: xfs_ialloc_read_agi() returned an error %d on %s.  Returning error.",

@@ -1169,11 +1154,9 @@ xfs_difree(
 		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);
-		down_read(&mp->m_peraglock);
 		pag = xfs_perag_get(mp, agno);
 		pag->pagi_freecount -= ilen - 1;
 		xfs_perag_put(pag);
-		up_read(&mp->m_peraglock);
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_ICOUNT, -ilen);
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -(ilen - 1));
 

@@ -1202,11 +1185,9 @@ xfs_difree(
 		 */
 		be32_add_cpu(&agi->agi_freecount, 1);
 		xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
-		down_read(&mp->m_peraglock);
 		pag = xfs_perag_get(mp, agno);
 		pag->pagi_freecount++;
 		xfs_perag_put(pag);
-		up_read(&mp->m_peraglock);
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, 1);
 	}
 

@@ -1328,9 +1309,7 @@ xfs_imap(
 		xfs_buf_t	*agbp;	/* agi buffer */
 		int		i;	/* temp state */
 
-		down_read(&mp->m_peraglock);
 		error = xfs_ialloc_read_agi(mp, tp, agno, &agbp);
-		up_read(&mp->m_peraglock);
 		if (error) {
 			xfs_fs_cmn_err(CE_ALERT, mp, "xfs_imap: "
 					"xfs_ialloc_read_agi() returned "

index 62efab2..940307a 100644
@@ -420,9 +420,7 @@ xfs_bulkstat(
 	while (XFS_BULKSTAT_UBLEFT(ubleft) && agno < mp->m_sb.sb_agcount) {
 		cond_resched();
 		bp = NULL;
-		down_read(&mp->m_peraglock);
 		error = xfs_ialloc_read_agi(mp, NULL, agno, &agbp);
-		up_read(&mp->m_peraglock);
 		if (error) {
 			/*
 			 * Skip this allocation group and go to the next one.

@@ -849,9 +847,7 @@ xfs_inumbers(
 	agbp = NULL;
 	while (left > 0 && agno < mp->m_sb.sb_agcount) {
 		if (agbp == NULL) {
-			down_read(&mp->m_peraglock);
 			error = xfs_ialloc_read_agi(mp, NULL, agno, &agbp);
-			up_read(&mp->m_peraglock);
 			if (error) {
 				/*
 				 * If we can't read the AGI of this ag,

97 lines not on this page · raw message

index f8a68a2..cfa7a5d 100644
@@ -207,8 +207,8 @@ typedef struct xfs_mount {
 	uint			m_ag_maxlevels;	/* XFS_AG_MAXLEVELS */
 	uint			m_bm_maxlevels[2]; /* XFS_BM_MAXLEVELS */
 	uint			m_in_maxlevels;	/* max inobt btree levels. */
-	struct xfs_perag	*m_perag;	/* per-ag accounting info */
-	struct rw_semaphore	m_peraglock;	/* lock for m_perag (pointer) */
+	struct radix_tree_root	m_perag_tree;	/* per-ag accounting info */
+	spinlock_t		m_perag_lock;	/* lock for m_perag_tree */
 	struct mutex		m_growlock;	/* growfs mutex */
 	int			m_fixedfsid[2];	/* unchanged for life of FS */
 	uint			m_dmevmask;	/* DMI events for this FS */

@@ -389,7 +389,12 @@ xfs_daddr_to_agbno(struct xfs_mount *mp, xfs_daddr_t d)
 static inline struct xfs_perag *
 xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno)
 {
-	return &mp->m_perag[agno];
+	struct xfs_perag	*pag;
+
+	spin_lock(&mp->m_perag_lock);
+	pag = radix_tree_lookup(&mp->m_perag_tree, agno);
+	spin_unlock(&mp->m_perag_lock);
+	return pag;
 }
 
 static inline void

@@ -450,7 +455,8 @@ extern struct xfs_dmops xfs_dmcore_xfs;
 #endif	/* __KERNEL__ */
 
 extern void	xfs_mod_sb(struct xfs_trans *, __int64_t);
-extern xfs_agnumber_t	xfs_initialize_perag(struct xfs_mount *, xfs_agnumber_t);
+extern int	xfs_initialize_perag(struct xfs_mount *, xfs_agnumber_t,
+					xfs_agnumber_t *);
 extern void	xfs_sb_from_disk(struct xfs_sb *, struct xfs_dsb *);
 extern void	xfs_sb_to_disk(struct xfs_dsb *, struct xfs_sb *, __int64_t);
 

index 6702bd8..18ae43f 100644
@@ -196,8 +196,8 @@ typedef struct xfs_perag_busy {
 #define XFS_PAGB_NUM_SLOTS	128
 #endif
 
-typedef struct xfs_perag
-{
+typedef struct xfs_perag {
+	atomic_t	pag_ref;	/* perag reference count */
 	char		pagf_init;	/* this agf's entry is initialized */
 	char		pagi_init;	/* this agi's entry is initialized */
 	char		pagf_metadata;	/* the agf is preferred to be metadata */

index c04dd83..f241fec 100644
@@ -215,6 +215,7 @@ xfs_free_perag(
 	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
 		spin_lock(&mp->m_perag_lock);
 		pag = radix_tree_delete(&mp->m_perag_tree, agno);
+		ASSERT(atomic_read(&pag->pag_ref) == 0);
 		spin_unlock(&mp->m_perag_lock);
 		ASSERT(pag);
 		kmem_free(pag->pagb_list);

index cfa7a5d..16b2212 100644
@@ -384,7 +384,7 @@ xfs_daddr_to_agbno(struct xfs_mount *mp, xfs_daddr_t d)
 }
 
 /*
- * perag get/put wrappers for eventual ref counting
+ * perag get/put wrappers for ref counting
  */
 static inline struct xfs_perag *
 xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno)

@@ -393,6 +393,12 @@ xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno)
 
 	spin_lock(&mp->m_perag_lock);
 	pag = radix_tree_lookup(&mp->m_perag_tree, agno);
+	if (pag) {
+		ASSERT(atomic_read(&pag->pag_ref) >= 0);
+		/* catch leaks in the positive direction during testing */
+		ASSERT(atomic_read(&pag->pag_ref) < 1000);
+		atomic_inc(&pag->pag_ref);
+	}
 	spin_unlock(&mp->m_perag_lock);
 	return pag;
 }

@@ -400,7 +406,8 @@ xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno)
 static inline void
 xfs_perag_put(struct xfs_perag *pag)
 {
-	/* nothing to see here, move along */
+	ASSERT(atomic_read(&pag->pag_ref) > 0);
+	atomic_dec(&pag->pag_ref);
 }
 
 /*

index c22a608..058fff1 100644
@@ -78,6 +78,33 @@ DECLARE_EVENT_CLASS(xfs_attr_list_class,
 	)
 )
 
+#define DEFINE_PERAG_REF_EVENT(name) \
+TRACE_EVENT(name, \
+	TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno, int refcount, \
+		 unsigned long caller_ip), \
+	TP_ARGS(mp, agno, refcount, caller_ip), \
+	TP_STRUCT__entry( \
+		__field(dev_t, dev) \
+		__field(xfs_agnumber_t, agno) \
+		__field(int, refcount) \
+		__field(unsigned long, caller_ip) \
+	), \
+	TP_fast_assign( \
+		__entry->dev = mp->m_super->s_dev; \
+		__entry->agno = agno; \
+		__entry->refcount = refcount; \
+		__entry->caller_ip = caller_ip; \
+	), \
+	TP_printk("dev %d:%d agno %u refcount %d caller %pf", \
+		  MAJOR(__entry->dev), MINOR(__entry->dev), \
+		  __entry->agno, \
+		  __entry->refcount, \
+		  (char *)__entry->caller_ip) \
+);
+
+DEFINE_PERAG_REF_EVENT(xfs_perag_get)
+DEFINE_PERAG_REF_EVENT(xfs_perag_put)
+
 #define DEFINE_ATTR_LIST_EVENT(name) \
 DEFINE_EVENT(xfs_attr_list_class, name, \
 	TP_PROTO(struct xfs_attr_list_context *ctx), \

index 18ae43f..963bc27 100644
@@ -197,6 +197,8 @@ typedef struct xfs_perag_busy {
 #endif
 
 typedef struct xfs_perag {
+	struct xfs_mount *pag_mount;	/* owner filesystem */
+	xfs_agnumber_t	pag_agno;	/* AG this structure belongs to */
 	atomic_t	pag_ref;	/* perag reference count */
 	char		pagf_init;	/* this agf's entry is initialized */
 	char		pagi_init;	/* this agi's entry is initialized */

index f241fec..049dbc7 100644
@@ -201,6 +201,38 @@ xfs_uuid_unmount(
 
 
 /*
+ * Reference counting access wrappers to the perag structures.
+ */
+struct xfs_perag *
+xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno)
+{
+	struct xfs_perag	*pag;
+	int			ref = 0;
+
+	spin_lock(&mp->m_perag_lock);
+	pag = radix_tree_lookup(&mp->m_perag_tree, agno);
+	if (pag) {
+		ASSERT(atomic_read(&pag->pag_ref) >= 0);
+		/* catch leaks in the positive direction during testing */
+		ASSERT(atomic_read(&pag->pag_ref) < 1000);
+		ref = atomic_inc_return(&pag->pag_ref);
+	}
+	spin_unlock(&mp->m_perag_lock);
+	trace_xfs_perag_get(mp, agno, ref, _RET_IP_);
+	return pag;
+}
+
+void
+xfs_perag_put(struct xfs_perag *pag)
+{
+	int	ref;
+
+	ASSERT(atomic_read(&pag->pag_ref) > 0);
+	ref = atomic_dec_return(&pag->pag_ref);
+	trace_xfs_perag_put(pag->pag_mount, pag->pag_agno, ref, _RET_IP_);
+}
+
+/*
  * Free up the resources associated with a mount structure.  Assume that
  * the structure was initially zeroed, so we can tell which fields got
  * initialized.

@@ -433,6 +465,8 @@ xfs_initialize_perag(
 			kmem_free(pag);
 			return -EEXIST;
 		}
+		pag->pag_agno = index;
+		pag->pag_mount = mp;
 		spin_unlock(&mp->m_perag_lock);
 		radix_tree_preload_end();
 	}

index 16b2212..e62fd1c 100644
@@ -386,29 +386,8 @@ xfs_daddr_to_agbno(struct xfs_mount *mp, xfs_daddr_t d)
 /*
  * perag get/put wrappers for ref counting
  */
-static inline struct xfs_perag *
-xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno)
-{
-	struct xfs_perag	*pag;
-
-	spin_lock(&mp->m_perag_lock);
-	pag = radix_tree_lookup(&mp->m_perag_tree, agno);
-	if (pag) {
-		ASSERT(atomic_read(&pag->pag_ref) >= 0);
-		/* catch leaks in the positive direction during testing */
-		ASSERT(atomic_read(&pag->pag_ref) < 1000);
-		atomic_inc(&pag->pag_ref);
-	}
-	spin_unlock(&mp->m_perag_lock);
-	return pag;
-}
-
-static inline void
-xfs_perag_put(struct xfs_perag *pag)
-{
-	ASSERT(atomic_read(&pag->pag_ref) > 0);
-	atomic_dec(&pag->pag_ref);
-}
+struct xfs_perag *xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno);
+void	xfs_perag_put(struct xfs_perag *pag);
 
 /*
  * Per-cpu superblock locking functions

index 2de7876..2eca601 100644
@@ -451,9 +451,6 @@ xfs_quiesce_data(
 	xfs_sync_data(mp, SYNC_WAIT);
 	xfs_qm_sync(mp, SYNC_WAIT);
 
-	/* drop inode references pinned by filestreams */
-	xfs_filestream_flush(mp);
-
 	/* write superblock and hoover up shutdown errors */
 	error = xfs_sync_fsdata(mp, SYNC_WAIT);
 

index 914d00d..390850e 100644
@@ -455,20 +455,6 @@ xfs_filestream_unmount(
 }
 
 /*
- * If the mount point's m_perag tree is going to be modified, all
- * outstanding cache entries must be flushed to avoid accessing reference count
- * addresses that have been freed.  The call to xfs_filestream_flush() must be
- * made inside the block that holds the m_perag_lock in write mode to do the
- * reallocation.
- */
-void
-xfs_filestream_flush(
-	xfs_mount_t	*mp)
-{
-	xfs_mru_cache_flush(mp->m_filestream);
-}
-
-/*
  * Return the AG of the filestream the file or directory belongs to, or
  * NULLAGNUMBER otherwise.
  */

index 58378b2..260f757 100644
@@ -135,7 +135,6 @@ int xfs_filestream_init(void);
 void xfs_filestream_uninit(void);
 int xfs_filestream_mount(struct xfs_mount *mp);
 void xfs_filestream_unmount(struct xfs_mount *mp);
-void xfs_filestream_flush(struct xfs_mount *mp);
 xfs_agnumber_t xfs_filestream_lookup_ag(struct xfs_inode *ip);
 int xfs_filestream_associate(struct xfs_inode *dip, struct xfs_inode *ip);
 void xfs_filestream_deassociate(struct xfs_inode *ip);

index 4b0613d..45ce15d 100644
@@ -398,7 +398,7 @@ exit:
  * guaranteed that all the free functions for all the elements have finished
  * executing and the reaper is not running.
  */
-void
+static void
 xfs_mru_cache_flush(
 	xfs_mru_cache_t		*mru)
 {

index 5d439f3..36dd3ec 100644
@@ -42,7 +42,6 @@ void xfs_mru_cache_uninit(void);
 int xfs_mru_cache_create(struct xfs_mru_cache **mrup, unsigned int lifetime_ms,
 			     unsigned int grp_count,
 			     xfs_mru_cache_free_func_t free_func);
-void xfs_mru_cache_flush(xfs_mru_cache_t *mru);
 void xfs_mru_cache_destroy(struct xfs_mru_cache *mru);
 int xfs_mru_cache_insert(struct xfs_mru_cache *mru, unsigned long key,
 				void *value);

index 049dbc7..be643e5 100644
@@ -432,11 +432,13 @@ xfs_initialize_perag(
 	xfs_agnumber_t	*maxagi)
 {
 	xfs_agnumber_t	index, max_metadata;
+	xfs_agnumber_t	first_initialised = 0;
 	xfs_perag_t	*pag;
 	xfs_agino_t	agino;
 	xfs_ino_t	ino;
 	xfs_sb_t	*sbp = &mp->m_sb;
 	xfs_ino_t	max_inum = XFS_MAXINUMBER_32;
+	int		error = -ENOMEM;
 
 	/* Check to see if the filesystem can overflow 32 bit inodes */
 	agino = XFS_OFFBNO_TO_AGINO(mp, sbp->sb_agblocks - 1, 0);

@@ -453,17 +455,20 @@ xfs_initialize_perag(
 			xfs_perag_put(pag);
 			continue;
 		}
+		if (!first_initialised)
+			first_initialised = index;
 		pag = kmem_zalloc(sizeof(*pag), KM_MAYFAIL);
 		if (!pag)
-			return -ENOMEM;
+			goto out_unwind;
 		if (radix_tree_preload(GFP_NOFS))
-			return -ENOMEM;
+			goto out_unwind;
 		spin_lock(&mp->m_perag_lock);
 		if (radix_tree_insert(&mp->m_perag_tree, index, pag)) {
 			BUG();
 			spin_unlock(&mp->m_perag_lock);
-			kmem_free(pag);
-			return -EEXIST;
+			radix_tree_preload_end();
+			error = -EEXIST;
+			goto out_unwind;
 		}
 		pag->pag_agno = index;
 		pag->pag_mount = mp;

@@ -523,6 +528,14 @@ xfs_initialize_perag(
 	if (maxagi)
 		*maxagi = index;
 	return 0;
+
+out_unwind:
+	kmem_free(pag);
+	for (; index > first_initialised; index--) {
+		pag = radix_tree_delete(&mp->m_perag_tree, index);
+		kmem_free(pag);
+	}
+	return error;
 }
 
 void

index 963bc27..b1a5a1f 100644
@@ -187,14 +187,8 @@ typedef struct xfs_perag_busy {
 /*
  * Per-ag incore structure, copies of information in agf and agi,
  * to improve the performance of allocation group selection.
- *
- * pick sizes which fit in allocation buckets well
  */
-#if (BITS_PER_LONG == 32)
-#define XFS_PAGB_NUM_SLOTS	84
-#elif (BITS_PER_LONG == 64)
 #define XFS_PAGB_NUM_SLOTS	128
-#endif
 
 typedef struct xfs_perag {
 	struct xfs_mount *pag_mount;	/* owner filesystem */

@@ -212,8 +206,6 @@ typedef struct xfs_perag {
 	__uint32_t	pagf_btreeblks;	/* # of blocks held in AGF btrees */
 	xfs_agino_t	pagi_freecount;	/* number of free inodes */
 	xfs_agino_t	pagi_count;	/* number of allocated inodes */
-	int		pagb_count;	/* pagb slots in use */
-	xfs_perag_busy_t *pagb_list;	/* unstable blocks */
 
 	/*
 	 * Inode allocation search lookup optimisation.

@@ -232,6 +224,8 @@ typedef struct xfs_perag {
 	rwlock_t	pag_ici_lock;	/* incore inode lock */
 	struct radix_tree_root pag_ici_root;	/* incore inode cache root */
 #endif
+	int		pagb_count;	/* pagb slots in use */
+	xfs_perag_busy_t pagb_list[XFS_PAGB_NUM_SLOTS];	/* unstable blocks */
 } xfs_perag_t;
 
 /*

index 4d66bb7..8aa181d 100644
@@ -2200,8 +2200,8 @@ xfs_alloc_read_agf(
 		pag->pagf_levels[XFS_BTNUM_CNTi] =
 			be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]);
 		spin_lock_init(&pag->pagb_lock);
-		pag->pagb_list = kmem_zalloc(XFS_PAGB_NUM_SLOTS *
-					sizeof(xfs_perag_busy_t), KM_SLEEP);
+		pag->pagb_count = 0;
+		memset(pag->pagb_list, 0, sizeof(pag->pagb_list));
 		pag->pagf_init = 1;
 	}
 #ifdef DEBUG

index be643e5..0df5045 100644
@@ -247,10 +247,9 @@ xfs_free_perag(
 	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
 		spin_lock(&mp->m_perag_lock);
 		pag = radix_tree_delete(&mp->m_perag_tree, agno);
+		ASSERT(pag);
 		ASSERT(atomic_read(&pag->pag_ref) == 0);
 		spin_unlock(&mp->m_perag_lock);
-		ASSERT(pag);
-		kmem_free(pag->pagb_list);
 		kmem_free(pag);
 	}
 }