Merge tag 'xfs-6.3-merge-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull moar xfs updates from Darrick Wong:
 "This contains a fix for a deadlock in the allocator. It continues the
  slow march towards being able to offline AGs, and it refactors the
  interface to the xfs allocator to be less indirection happy.

  Summary:

   - Fix a deadlock in the free space allocator due to the AG-walking
     algorithm forgetting to follow AG-order locking rules

   - Make the inode allocator prefer existing free inodes instead of
     failing to allocate new inode chunks when free space is low

   - Set minleft correctly when setting allocator parameters for bmap
     changes

   - Fix uninitialized variable access in the getfsmap code

   - Make a distinction between active and passive per-AG structure
     references. For now, active references are taken to perform some
     work in an AG on behalf of a high level operation; passive
     references are used by lower level code to finish operations
     started by other threads. Eventually this will become part of
     online shrink

   - Split out all the different allocator strategies into separate
     functions to move us away from design antipattern of filling out a
     huge structure for various differentish things and issuing a single
     function multiplexing call

   - Various cleanups in the filestreams allocator code, which we might
     very well want to deprecate instead of continuing

   - Fix a bug with the agi rotor code that was introduced earlier in
     this series"

* tag 'xfs-6.3-merge-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (44 commits)
  xfs: restore old agirotor behavior
  xfs: fix uninitialized variable access
  xfs: refactor the filestreams allocator pick functions
  xfs: return a referenced perag from filestreams allocator
  xfs: pass perag to filestreams tracing
  xfs: use for_each_perag_wrap in xfs_filestream_pick_ag
  xfs: track an active perag reference in filestreams
  xfs: factor out MRU hit case in xfs_filestream_select_ag
  xfs: remove xfs_filestream_select_ag() longest extent check
  xfs: merge new filestream AG selection into xfs_filestream_select_ag()
  xfs: merge filestream AG lookup into xfs_filestream_select_ag()
  xfs: move xfs_bmap_btalloc_filestreams() to xfs_filestreams.c
  xfs: use xfs_bmap_longest_free_extent() in filestreams
  xfs: get rid of notinit from xfs_bmap_longest_free_extent
  xfs: factor out filestreams from xfs_bmap_btalloc_nullfb
  xfs: convert trim to use for_each_perag_range
  xfs: convert xfs_alloc_vextent_iterate_ags() to use perag walker
  xfs: move the minimum agno checks into xfs_alloc_vextent_check_args
  xfs: fold xfs_alloc_ag_vextent() into callers
  xfs: move allocation accounting to xfs_alloc_vextent_set_fsbno()
  ...

36 files changed, 1536 insertions, 1243 deletions

diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c
index bb0c700afe3cb1..86696a1c6891b7 100644
--- a/fs/xfs/libxfs/xfs_ag.c
+++ b/fs/xfs/libxfs/xfs_ag.c
@@ -44,16 +44,15 @@ xfs_perag_get(
 	xfs_agnumber_t		agno)
 {
 	struct xfs_perag	*pag;
-	int			ref = 0;
 
 	rcu_read_lock();
 	pag = radix_tree_lookup(&mp->m_perag_tree, agno);
 	if (pag) {
+		trace_xfs_perag_get(pag, _RET_IP_);
 		ASSERT(atomic_read(&pag->pag_ref) >= 0);
-		ref = atomic_inc_return(&pag->pag_ref);
+		atomic_inc(&pag->pag_ref);
 	}
 	rcu_read_unlock();
-	trace_xfs_perag_get(mp, agno, ref, _RET_IP_);
 	return pag;
 }
 
@@ -68,7 +67,6 @@ xfs_perag_get_tag(
 {
 	struct xfs_perag	*pag;
 	int			found;
-	int			ref;
 
 	rcu_read_lock();
 	found = radix_tree_gang_lookup_tag(&mp->m_perag_tree,
@@ -77,9 +75,9 @@ xfs_perag_get_tag(
 		rcu_read_unlock();
 		return NULL;
 	}
-	ref = atomic_inc_return(&pag->pag_ref);
+	trace_xfs_perag_get_tag(pag, _RET_IP_);
+	atomic_inc(&pag->pag_ref);
 	rcu_read_unlock();
-	trace_xfs_perag_get_tag(mp, pag->pag_agno, ref, _RET_IP_);
 	return pag;
 }
 
@@ -87,11 +85,68 @@ void
 xfs_perag_put(
 	struct xfs_perag	*pag)
 {
-	int	ref;
-
+	trace_xfs_perag_put(pag, _RET_IP_);
 	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_);
+	atomic_dec(&pag->pag_ref);
+}
+
+/*
+ * Active references for perag structures. This is for short term access to the
+ * per ag structures for walking trees or accessing state. If an AG is being
+ * shrunk or is offline, then this will fail to find that AG and return NULL
+ * instead.
+ */
+struct xfs_perag *
+xfs_perag_grab(
+	struct xfs_mount	*mp,
+	xfs_agnumber_t		agno)
+{
+	struct xfs_perag	*pag;
+
+	rcu_read_lock();
+	pag = radix_tree_lookup(&mp->m_perag_tree, agno);
+	if (pag) {
+		trace_xfs_perag_grab(pag, _RET_IP_);
+		if (!atomic_inc_not_zero(&pag->pag_active_ref))
+			pag = NULL;
+	}
+	rcu_read_unlock();
+	return pag;
+}
+
+/*
+ * search from @first to find the next perag with the given tag set.
+ */
+struct xfs_perag *
+xfs_perag_grab_tag(
+	struct xfs_mount	*mp,
+	xfs_agnumber_t		first,
+	int			tag)
+{
+	struct xfs_perag	*pag;
+	int			found;
+
+	rcu_read_lock();
+	found = radix_tree_gang_lookup_tag(&mp->m_perag_tree,
+					(void **)&pag, first, 1, tag);
+	if (found <= 0) {
+		rcu_read_unlock();
+		return NULL;
+	}
+	trace_xfs_perag_grab_tag(pag, _RET_IP_);
+	if (!atomic_inc_not_zero(&pag->pag_active_ref))
+		pag = NULL;
+	rcu_read_unlock();
+	return pag;
+}
+
+void
+xfs_perag_rele(
+	struct xfs_perag	*pag)
+{
+	trace_xfs_perag_rele(pag, _RET_IP_);
+	if (atomic_dec_and_test(&pag->pag_active_ref))
+		wake_up(&pag->pag_active_wq);
 }
 
 /*
@@ -196,6 +251,10 @@ xfs_free_perag(
 		cancel_delayed_work_sync(&pag->pag_blockgc_work);
 		xfs_buf_hash_destroy(pag);
 
+		/* drop the mount's active reference */
+		xfs_perag_rele(pag);
+		XFS_IS_CORRUPT(pag->pag_mount,
+				atomic_read(&pag->pag_active_ref) != 0);
 		call_rcu(&pag->rcu_head, __xfs_free_perag);
 	}
 }
@@ -314,6 +373,7 @@ xfs_initialize_perag(
 		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);
+		init_waitqueue_head(&pag->pag_active_wq);
 		pag->pagb_count = 0;
 		pag->pagb_tree = RB_ROOT;
 #endif /* __KERNEL__ */
@@ -322,6 +382,9 @@ xfs_initialize_perag(
 		if (error)
 			goto out_remove_pag;
 
+		/* Active ref owned by mount indicates AG is online. */
+		atomic_set(&pag->pag_active_ref, 1);
+
 		/* first new pag is fully initialized */
 		if (first_initialised == NULLAGNUMBER)
 			first_initialised = index;
@@ -824,7 +887,7 @@ xfs_ag_shrink_space(
 	struct xfs_alloc_arg	args = {
 		.tp	= *tpp,
 		.mp	= mp,
-		.type	= XFS_ALLOCTYPE_THIS_BNO,
+		.pag	= pag,
 		.minlen = delta,
 		.maxlen = delta,
 		.oinfo	= XFS_RMAP_OINFO_SKIP_UPDATE,
@@ -856,14 +919,11 @@ xfs_ag_shrink_space(
 	if (delta >= aglen)
 		return -EINVAL;
 
-	args.fsbno = XFS_AGB_TO_FSB(mp, pag->pag_agno, aglen - delta);
-
 	/*
 	 * Make sure that the last inode cluster cannot overlap with the new
 	 * end of the AG, even if it's sparse.
 	 */
-	error = xfs_ialloc_check_shrink(*tpp, pag->pag_agno, agibp,
-			aglen - delta);
+	error = xfs_ialloc_check_shrink(pag, *tpp, agibp, aglen - delta);
 	if (error)
 		return error;
 
@@ -876,7 +936,8 @@ xfs_ag_shrink_space(
 		return error;
 
 	/* internal log shouldn't also show up in the free space btrees */
-	error = xfs_alloc_vextent(&args);
+	error = xfs_alloc_vextent_exact_bno(&args,
+			XFS_AGB_TO_FSB(mp, pag->pag_agno, aglen - delta));
 	if (!error && args.agbno == NULLAGBLOCK)
 		error = -ENOSPC;
 
diff --git a/fs/xfs/libxfs/xfs_ag.h b/fs/xfs/libxfs/xfs_ag.h
index 191b22b9a35bfd..5e18536dfdcecc 100644
--- a/fs/xfs/libxfs/xfs_ag.h
+++ b/fs/xfs/libxfs/xfs_ag.h
@@ -32,14 +32,12 @@ struct xfs_ag_resv {
 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 */
-	char		pagf_metadata;	/* the agf is preferred to be metadata */
-	char		pagi_inodeok;	/* The agi is ok for inodes */
+	atomic_t	pag_ref;	/* passive reference count */
+	atomic_t	pag_active_ref;	/* active reference count */
+	wait_queue_head_t pag_active_wq;/* woken active_ref falls to zero */
+	unsigned long	pag_opstate;
 	uint8_t		pagf_levels[XFS_BTNUM_AGF];
 					/* # of levels in bno & cnt btree */
-	bool		pagf_agflreset; /* agfl requires reset before use */
 	uint32_t	pagf_flcount;	/* count of blocks in freelist */
 	xfs_extlen_t	pagf_freeblks;	/* total free blocks */
 	xfs_extlen_t	pagf_longest;	/* longest free space */
@@ -106,16 +104,44 @@ struct xfs_perag {
 #endif /* __KERNEL__ */
 };
 
+/*
+ * Per-AG operational state. These are atomic flag bits.
+ */
+#define XFS_AGSTATE_AGF_INIT		0
+#define XFS_AGSTATE_AGI_INIT		1
+#define XFS_AGSTATE_PREFERS_METADATA	2
+#define XFS_AGSTATE_ALLOWS_INODES	3
+#define XFS_AGSTATE_AGFL_NEEDS_RESET	4
+
+#define __XFS_AG_OPSTATE(name, NAME) \
+static inline bool xfs_perag_ ## name (struct xfs_perag *pag) \
+{ \
+	return test_bit(XFS_AGSTATE_ ## NAME, &pag->pag_opstate); \
+}
+
+__XFS_AG_OPSTATE(initialised_agf, AGF_INIT)
+__XFS_AG_OPSTATE(initialised_agi, AGI_INIT)
+__XFS_AG_OPSTATE(prefers_metadata, PREFERS_METADATA)
+__XFS_AG_OPSTATE(allows_inodes, ALLOWS_INODES)
+__XFS_AG_OPSTATE(agfl_needs_reset, AGFL_NEEDS_RESET)
+
 int xfs_initialize_perag(struct xfs_mount *mp, xfs_agnumber_t agcount,
 			xfs_rfsblock_t dcount, xfs_agnumber_t *maxagi);
 int xfs_initialize_perag_data(struct xfs_mount *mp, xfs_agnumber_t agno);
 void xfs_free_perag(struct xfs_mount *mp);
 
+/* Passive AG references */
 struct xfs_perag *xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno);
 struct xfs_perag *xfs_perag_get_tag(struct xfs_mount *mp, xfs_agnumber_t agno,
 		unsigned int tag);
 void xfs_perag_put(struct xfs_perag *pag);
 
+/* Active AG references */
+struct xfs_perag *xfs_perag_grab(struct xfs_mount *, xfs_agnumber_t);
+struct xfs_perag *xfs_perag_grab_tag(struct xfs_mount *, xfs_agnumber_t,
+				   int tag);
+void xfs_perag_rele(struct xfs_perag *pag);
+
 /*
  * Per-ag geometry infomation and validation
  */
@@ -193,31 +219,86 @@ xfs_perag_next(
 	struct xfs_mount	*mp = pag->pag_mount;
 
 	*agno = pag->pag_agno + 1;
-	xfs_perag_put(pag);
-	if (*agno > end_agno)
-		return NULL;
-	return xfs_perag_get(mp, *agno);
+	xfs_perag_rele(pag);
+	while (*agno <= end_agno) {
+		pag = xfs_perag_grab(mp, *agno);
+		if (pag)
+			return pag;
+		(*agno)++;
+	}
+	return NULL;
 }
 
 #define for_each_perag_range(mp, agno, end_agno, pag) \
-	for ((pag) = xfs_perag_get((mp), (agno)); \
+	for ((pag) = xfs_perag_grab((mp), (agno)); \
 		(pag) != NULL; \
 		(pag) = xfs_perag_next((pag), &(agno), (end_agno)))
 
 #define for_each_perag_from(mp, agno, pag) \
 	for_each_perag_range((mp), (agno), (mp)->m_sb.sb_agcount - 1, (pag))
 
-
 #define for_each_perag(mp, agno, pag) \
 	(agno) = 0; \
 	for_each_perag_from((mp), (agno), (pag))
 
 #define for_each_perag_tag(mp, agno, pag, tag) \
-	for ((agno) = 0, (pag) = xfs_perag_get_tag((mp), 0, (tag)); \
+	for ((agno) = 0, (pag) = xfs_perag_grab_tag((mp), 0, (tag)); \
 		(pag) != NULL; \
 		(agno) = (pag)->pag_agno + 1, \
-		xfs_perag_put(pag), \
-		(pag) = xfs_perag_get_tag((mp), (agno), (tag)))
+		xfs_perag_rele(pag), \
+		(pag) = xfs_perag_grab_tag((mp), (agno), (tag)))
+
+static inline struct xfs_perag *
+xfs_perag_next_wrap(
+	struct xfs_perag	*pag,
+	xfs_agnumber_t		*agno,
+	xfs_agnumber_t		stop_agno,
+	xfs_agnumber_t		restart_agno,
+	xfs_agnumber_t		wrap_agno)
+{
+	struct xfs_mount	*mp = pag->pag_mount;
+
+	*agno = pag->pag_agno + 1;
+	xfs_perag_rele(pag);
+	while (*agno != stop_agno) {
+		if (*agno >= wrap_agno) {
+			if (restart_agno >= stop_agno)
+				break;
+			*agno = restart_agno;
+		}
+
+		pag = xfs_perag_grab(mp, *agno);
+		if (pag)
+			return pag;
+		(*agno)++;
+	}
+	return NULL;
+}
+
+/*
+ * Iterate all AGs from start_agno through wrap_agno, then restart_agno through
+ * (start_agno - 1).
+ */
+#define for_each_perag_wrap_range(mp, start_agno, restart_agno, wrap_agno, agno, pag) \
+	for ((agno) = (start_agno), (pag) = xfs_perag_grab((mp), (agno)); \
+		(pag) != NULL; \
+		(pag) = xfs_perag_next_wrap((pag), &(agno), (start_agno), \
+				(restart_agno), (wrap_agno)))
+/*
+ * Iterate all AGs from start_agno through wrap_agno, then 0 through
+ * (start_agno - 1).
+ */
+#define for_each_perag_wrap_at(mp, start_agno, wrap_agno, agno, pag) \
+	for_each_perag_wrap_range((mp), (start_agno), 0, (wrap_agno), (agno), (pag))
+
+/*
+ * Iterate all AGs from start_agno through to the end of the filesystem, then 0
+ * through (start_agno - 1).
+ */
+#define for_each_perag_wrap(mp, start_agno, agno, pag) \
+	for_each_perag_wrap_at((mp), (start_agno), (mp)->m_sb.sb_agcount, \
+				(agno), (pag))
+
 
 struct aghdr_init_data {
 	/* per ag data */
diff --git a/fs/xfs/libxfs/xfs_ag_resv.c b/fs/xfs/libxfs/xfs_ag_resv.c
index 5af123d13a637c..7fd1fea95552f1 100644
--- a/fs/xfs/libxfs/xfs_ag_resv.c
+++ b/fs/xfs/libxfs/xfs_ag_resv.c
@@ -264,7 +264,7 @@ xfs_ag_resv_init(
 		if (error)
 			goto out;
 
-		error = xfs_finobt_calc_reserves(mp, tp, pag, &ask, &used);
+		error = xfs_finobt_calc_reserves(pag, tp, &ask, &used);
 		if (error)
 			goto out;
 
diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index f8ff81c3de761f..6a037173d20d99 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -36,10 +36,6 @@ struct workqueue_struct *xfs_alloc_wq;
 #define	XFSA_FIXUP_BNO_OK	1
 #define	XFSA_FIXUP_CNT_OK	2
 
-STATIC int xfs_alloc_ag_vextent_exact(xfs_alloc_arg_t *);
-STATIC int xfs_alloc_ag_vextent_near(xfs_alloc_arg_t *);
-STATIC int xfs_alloc_ag_vextent_size(xfs_alloc_arg_t *);
-
 /*
  * Size of the AGFL.  For CRC-enabled filesystes we steal a couple of slots in
  * the beginning of the block for a proper header with the location information
@@ -772,8 +768,6 @@ xfs_alloc_cur_setup(
 	int			error;
 	int			i;
 
-	ASSERT(args->alignment == 1 || args->type != XFS_ALLOCTYPE_THIS_BNO);
-
 	acur->cur_len = args->maxlen;
 	acur->rec_bno = 0;
 	acur->rec_len = 0;
@@ -887,7 +881,6 @@ xfs_alloc_cur_check(
 	 * We have an aligned record that satisfies minlen and beats or matches
 	 * the candidate extent size. Compare locality for near allocation mode.
 	 */
-	ASSERT(args->type == XFS_ALLOCTYPE_NEAR_BNO);
 	diff = xfs_alloc_compute_diff(args->agbno, args->len,
 				      args->alignment, args->datatype,
 				      bnoa, lena, &bnew);
@@ -1133,78 +1126,6 @@ error:
 }
 
 /*
- * Allocate a variable extent in the allocation group agno.
- * Type and bno are used to determine where in the allocation group the
- * extent will start.
- * Extent's length (returned in *len) will be between minlen and maxlen,
- * and of the form k * prod + mod unless there's nothing that large.
- * Return the starting a.g. block, or NULLAGBLOCK if we can't do it.
- */
-STATIC int			/* error */
-xfs_alloc_ag_vextent(
-	xfs_alloc_arg_t	*args)	/* argument structure for allocation */
-{
-	int		error=0;
-
-	ASSERT(args->minlen > 0);
-	ASSERT(args->maxlen > 0);
-	ASSERT(args->minlen <= args->maxlen);
-	ASSERT(args->mod < args->prod);
-	ASSERT(args->alignment > 0);
-
-	/*
-	 * Branch to correct routine based on the type.
-	 */
-	args->wasfromfl = 0;
-	switch (args->type) {
-	case XFS_ALLOCTYPE_THIS_AG:
-		error = xfs_alloc_ag_vextent_size(args);
-		break;
-	case XFS_ALLOCTYPE_NEAR_BNO:
-		error = xfs_alloc_ag_vextent_near(args);
-		break;
-	case XFS_ALLOCTYPE_THIS_BNO:
-		error = xfs_alloc_ag_vextent_exact(args);
-		break;
-	default:
-		ASSERT(0);
-		/* NOTREACHED */
-	}
-
-	if (error || args->agbno == NULLAGBLOCK)
-		return error;
-
-	ASSERT(args->len >= args->minlen);
-	ASSERT(args->len <= args->maxlen);
-	ASSERT(!args->wasfromfl || args->resv != XFS_AG_RESV_AGFL);
-	ASSERT(args->agbno % args->alignment == 0);
-
-	/* if not file data, insert new block into the reverse map btree */
-	if (!xfs_rmap_should_skip_owner_update(&args->oinfo)) {
-		error = xfs_rmap_alloc(args->tp, args->agbp, args->pag,
-				       args->agbno, args->len, &args->oinfo);
-		if (error)
-			return error;
-	}
-
-	if (!args->wasfromfl) {
-		error = xfs_alloc_update_counters(args->tp, args->agbp,
-						  -((long)(args->len)));
-		if (error)
-			return error;
-
-		ASSERT(!xfs_extent_busy_search(args->mp, args->pag,
-					      args->agbno, args->len));
-	}
-
-	xfs_ag_resv_alloc_extent(args->pag, args->resv, args);
-
-	XFS_STATS_INC(args->mp, xs_allocx);
-	XFS_STATS_ADD(args->mp, xs_allocb, args->len);
-	return error;
-}
-
-/*
  * Allocate a variable extent at exactly agno/bno.
  * Extent's length (returned in *len) will be between minlen and maxlen,
  * and of the form k * prod + mod unless there's nothing that large.
@@ -1389,7 +1310,6 @@ xfs_alloc_ag_vextent_locality(
 	bool			fbinc;
 
 	ASSERT(acur->len == 0);
-	ASSERT(args->type == XFS_ALLOCTYPE_NEAR_BNO);
 
 	*stat = 0;
 
@@ -2435,7 +2355,7 @@ xfs_agfl_reset(
 	struct xfs_mount	*mp = tp->t_mountp;
 	struct xfs_agf		*agf = agbp->b_addr;
 
-	ASSERT(pag->pagf_agflreset);
+	ASSERT(xfs_perag_agfl_needs_reset(pag));
 	trace_xfs_agfl_reset(mp, agf, 0, _RET_IP_);
 
 	xfs_warn(mp,
@@ -2450,7 +2370,7 @@ xfs_agfl_reset(
 				    XFS_AGF_FLCOUNT);
 
 	pag->pagf_flcount = 0;
-	pag->pagf_agflreset = false;
+	clear_bit(XFS_AGSTATE_AGFL_NEEDS_RESET, &pag->pag_opstate);
 }
 
 /*
@@ -2605,7 +2525,7 @@ xfs_alloc_fix_freelist(
 	/* deferred ops (AGFL block frees) require permanent transactions */
 	ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
 
-	if (!pag->pagf_init) {
+	if (!xfs_perag_initialised_agf(pag)) {
 		error = xfs_alloc_read_agf(pag, tp, flags, &agbp);
 		if (error) {
 			/* Couldn't lock the AGF so skip this AG. */
@@ -2620,7 +2540,8 @@ xfs_alloc_fix_freelist(
 	 * somewhere else if we are not being asked to try harder at this
 	 * point
 	 */
-	if (pag->pagf_metadata && (args->datatype & XFS_ALLOC_USERDATA) &&
+	if (xfs_perag_prefers_metadata(pag) &&
+	    (args->datatype & XFS_ALLOC_USERDATA) &&
 	    (flags & XFS_ALLOC_FLAG_TRYLOCK)) {
 		ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));
 		goto out_agbp_relse;
@@ -2646,7 +2567,7 @@ xfs_alloc_fix_freelist(
 	}
 
 	/* reset a padding mismatched agfl before final free space check */
-	if (pag->pagf_agflreset)
+	if (xfs_perag_agfl_needs_reset(pag))
 		xfs_agfl_reset(tp, agbp, pag);
 
 	/* If there isn't enough total space or single-extent, reject it. */
@@ -2707,7 +2628,6 @@ xfs_alloc_fix_freelist(
 	targs.agbp = agbp;
 	targs.agno = args->agno;
 	targs.alignment = targs.minlen = targs.prod = 1;
-	targs.type = XFS_ALLOCTYPE_THIS_AG;
 	targs.pag = pag;
 	error = xfs_alloc_read_agfl(pag, tp, &agflbp);
 	if (error)
@@ -2720,7 +2640,7 @@ xfs_alloc_fix_freelist(
 		targs.resv = XFS_AG_RESV_AGFL;
 
 		/* Allocate as many blocks as possible at once. */
-		error = xfs_alloc_ag_vextent(&targs);
+		error = xfs_alloc_ag_vextent_size(&targs);
 		if (error)
 			goto out_agflbp_relse;
 
@@ -2734,6 +2654,18 @@ xfs_alloc_fix_freelist(
 				break;
 			goto out_agflbp_relse;
 		}
+
+		if (!xfs_rmap_should_skip_owner_update(&targs.oinfo)) {
+			error = xfs_rmap_alloc(tp, agbp, pag,
+				       targs.agbno, targs.len, &targs.oinfo);
+			if (error)
+				goto out_agflbp_relse;
+		}
+		error = xfs_alloc_update_counters(tp, agbp,
+						  -((long)(targs.len)));
+		if (error)
+			goto out_agflbp_relse;
+
 		/*
 		 * Put each allocated block on the list.
 		 */
@@ -2803,7 +2735,7 @@ xfs_alloc_get_freelist(
 	if (be32_to_cpu(agf->agf_flfirst) == xfs_agfl_size(mp))
 		agf->agf_flfirst = 0;
 
-	ASSERT(!pag->pagf_agflreset);
+	ASSERT(!xfs_perag_agfl_needs_reset(pag));
 	be32_add_cpu(&agf->agf_flcount, -1);
 	pag->pagf_flcount--;
 
@@ -2892,7 +2824,7 @@ xfs_alloc_put_freelist(
 	if (be32_to_cpu(agf->agf_fllast) == xfs_agfl_size(mp))
 		agf->agf_fllast = 0;
 
-	ASSERT(!pag->pagf_agflreset);
+	ASSERT(!xfs_perag_agfl_needs_reset(pag));
 	be32_add_cpu(&agf->agf_flcount, 1);
 	pag->pagf_flcount++;
 
@@ -3099,7 +3031,7 @@ xfs_alloc_read_agf(
 		return error;
 
 	agf = agfbp->b_addr;
-	if (!pag->pagf_init) {
+	if (!xfs_perag_initialised_agf(pag)) {
 		pag->pagf_freeblks = be32_to_cpu(agf->agf_freeblks);
 		pag->pagf_btreeblks = be32_to_cpu(agf->agf_btreeblks);
 		pag->pagf_flcount = be32_to_cpu(agf->agf_flcount);
@@ -3111,8 +3043,8 @@ xfs_alloc_read_agf(
 		pag->pagf_levels[XFS_BTNUM_RMAPi] =
 			be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAPi]);
 		pag->pagf_refcount_level = be32_to_cpu(agf->agf_refcount_level);
-		pag->pagf_init = 1;
-		pag->pagf_agflreset = xfs_agfl_needs_reset(pag->pag_mount, agf);
+		if (xfs_agfl_needs_reset(pag->pag_mount, agf))
+			set_bit(XFS_AGSTATE_AGFL_NEEDS_RESET, &pag->pag_opstate);
 
 		/*
 		 * Update the in-core allocbt counter. Filter out the rmapbt
@@ -3127,6 +3059,8 @@ xfs_alloc_read_agf(
 		if (allocbt_blks > 0)
 			atomic64_add(allocbt_blks,
 					&pag->pag_mount->m_allocbt_blks);
+
+		set_bit(XFS_AGSTATE_AGF_INIT, &pag->pag_opstate);
 	}
 #ifdef DEBUG
 	else if (!xfs_is_shutdown(pag->pag_mount)) {
@@ -3148,26 +3082,25 @@ xfs_alloc_read_agf(
 }
 
 /*
- * Allocate an extent (variable-size).
- * Depending on the allocation type, we either look in a single allocation
- * group or loop over the allocation groups to find the result.
+ * Pre-proces allocation arguments to set initial state that we don't require
+ * callers to set up correctly, as well as bounds check the allocation args
+ * that are set up.
  */
-int				/* error */
-xfs_alloc_vextent(
-	struct xfs_alloc_arg	*args)	/* allocation argument structure */
+static int
+xfs_alloc_vextent_check_args(
+	struct xfs_alloc_arg	*args,
+	xfs_fsblock_t		target,
+	xfs_agnumber_t		*minimum_agno)
 {
-	xfs_agblock_t		agsize;	/* allocation group size */
-	int			error;
-	int			flags;	/* XFS_ALLOC_FLAG_... locking flags */
-	struct xfs_mount	*mp;	/* mount structure pointer */
-	xfs_agnumber_t		sagno;	/* starting allocation group number */
-	xfs_alloctype_t		type;	/* input allocation type */
-	int			bump_rotor = 0;
-	xfs_agnumber_t		rotorstep = xfs_rotorstep; /* inode32 agf stepper */
-
-	mp = args->mp;
-	type = args->otype = args->type;
-	args->agbno = NULLAGBLOCK;
+	struct xfs_mount	*mp = args->mp;
+	xfs_agblock_t		agsize;
+
+	args->fsbno = NULLFSBLOCK;
+
+	*minimum_agno = 0;
+	if (args->tp->t_highest_agno != NULLAGNUMBER)
+		*minimum_agno = args->tp->t_highest_agno;
+
 	/*
 	 * Just fix this up, for the case where the last a.g. is shorter
 	 * (or there's only one a.g.) and the caller couldn't easily figure
@@ -3178,168 +3111,414 @@ xfs_alloc_vextent(
 		args->maxlen = agsize;
 	if (args->alignment == 0)
 		args->alignment = 1;
-	ASSERT(XFS_FSB_TO_AGNO(mp, args->fsbno) < mp->m_sb.sb_agcount);
-	ASSERT(XFS_FSB_TO_AGBNO(mp, args->fsbno) < agsize);
+
+	ASSERT(args->minlen > 0);
+	ASSERT(args->maxlen > 0);
+	ASSERT(args->alignment > 0);
+	ASSERT(args->resv != XFS_AG_RESV_AGFL);
+
+	ASSERT(XFS_FSB_TO_AGNO(mp, target) < mp->m_sb.sb_agcount);
+	ASSERT(XFS_FSB_TO_AGBNO(mp, target) < agsize);
 	ASSERT(args->minlen <= args->maxlen);
 	ASSERT(args->minlen <= agsize);
 	ASSERT(args->mod < args->prod);
-	if (XFS_FSB_TO_AGNO(mp, args->fsbno) >= mp->m_sb.sb_agcount ||
-	    XFS_FSB_TO_AGBNO(mp, args->fsbno) >= agsize ||
+
+	if (XFS_FSB_TO_AGNO(mp, target) >= mp->m_sb.sb_agcount ||
+	    XFS_FSB_TO_AGBNO(mp, target) >= agsize ||
 	    args->minlen > args->maxlen || args->minlen > agsize ||
 	    args->mod >= args->prod) {
-		args->fsbno = NULLFSBLOCK;
 		trace_xfs_alloc_vextent_badargs(args);
+		return -ENOSPC;
+	}
+
+	if (args->agno != NULLAGNUMBER && *minimum_agno > args->agno) {
+		trace_xfs_alloc_vextent_skip_deadlock(args);
+		return -ENOSPC;
+	}
+	return 0;
+
+}
+
+/*
+ * Prepare an AG for allocation. If the AG is not prepared to accept the
+ * allocation, return failure.
+ *
+ * XXX(dgc): The complexity of "need_pag" will go away as all caller paths are
+ * modified to hold their own perag references.
+ */
+static int
+xfs_alloc_vextent_prepare_ag(
+	struct xfs_alloc_arg	*args)
+{
+	bool			need_pag = !args->pag;
+	int			error;
+
+	if (need_pag)
+		args->pag = xfs_perag_get(args->mp, args->agno);
+
+	args->agbp = NULL;
+	error = xfs_alloc_fix_freelist(args, 0);
+	if (error) {
+		trace_xfs_alloc_vextent_nofix(args);
+		if (need_pag)
+			xfs_perag_put(args->pag);
+		args->agbno = NULLAGBLOCK;
+		return error;
+	}
+	if (!args->agbp) {
+		/* cannot allocate in this AG at all */
+		trace_xfs_alloc_vextent_noagbp(args);
+		args->agbno = NULLAGBLOCK;
 		return 0;
 	}
+	args->wasfromfl = 0;
+	return 0;
+}
 
-	switch (type) {
-	case XFS_ALLOCTYPE_THIS_AG:
-	case XFS_ALLOCTYPE_NEAR_BNO:
-	case XFS_ALLOCTYPE_THIS_BNO:
-		/*
-		 * These three force us into a single a.g.
-		 */
-		args->agno = XFS_FSB_TO_AGNO(mp, args->fsbno);
-		args->pag = xfs_perag_get(mp, args->agno);
-		error = xfs_alloc_fix_freelist(args, 0);
-		if (error) {
-			trace_xfs_alloc_vextent_nofix(args);
-			goto error0;
-		}
-		if (!args->agbp) {
-			trace_xfs_alloc_vextent_noagbp(args);
+/*
+ * Post-process allocation results to account for the allocation if it succeed
+ * and set the allocated block number correctly for the caller.
+ *
+ * XXX: we should really be returning ENOSPC for ENOSPC, not
+ * hiding it behind a "successful" NULLFSBLOCK allocation.
+ */
+static int
+xfs_alloc_vextent_finish(
+	struct xfs_alloc_arg	*args,
+	xfs_agnumber_t		minimum_agno,
+	int			alloc_error,
+	bool			drop_perag)
+{
+	struct xfs_mount	*mp = args->mp;
+	int			error = 0;
+
+	/*
+	 * We can end up here with a locked AGF. If we failed, the caller is
+	 * likely going to try to allocate again with different parameters, and
+	 * that can widen the AGs that are searched for free space. If we have
+	 * to do BMBT block allocation, we have to do a new allocation.
+	 *
+	 * Hence leaving this function with the AGF locked opens up potential
+	 * ABBA AGF deadlocks because a future allocation attempt in this
+	 * transaction may attempt to lock a lower number AGF.
+	 *
+	 * We can't release the AGF until the transaction is commited, so at
+	 * this point we must update the "first allocation" tracker to point at
+	 * this AG if the tracker is empty or points to a lower AG. This allows
+	 * the next allocation attempt to be modified appropriately to avoid
+	 * deadlocks.
+	 */
+	if (args->agbp &&
+	    (args->tp->t_highest_agno == NULLAGNUMBER ||
+	     args->agno > minimum_agno))
+		args->tp->t_highest_agno = args->agno;
+
+	/*
+	 * If the allocation failed with an error or we had an ENOSPC result,
+	 * preserve the returned error whilst also marking the allocation result
+	 * as "no extent allocated". This ensures that callers that fail to
+	 * capture the error will still treat it as a failed allocation.
+	 */
+	if (alloc_error || args->agbno == NULLAGBLOCK) {
+		args->fsbno = NULLFSBLOCK;
+		error = alloc_error;
+		goto out_drop_perag;
+	}
+
+	args->fsbno = XFS_AGB_TO_FSB(mp, args->agno, args->agbno);
+
+	ASSERT(args->len >= args->minlen);
+	ASSERT(args->len <= args->maxlen);
+	ASSERT(args->agbno % args->alignment == 0);
+	XFS_AG_CHECK_DADDR(mp, XFS_FSB_TO_DADDR(mp, args->fsbno), args->len);
+
+	/* if not file data, insert new block into the reverse map btree */
+	if (!xfs_rmap_should_skip_owner_update(&args->oinfo)) {
+		error = xfs_rmap_alloc(args->tp, args->agbp, args->pag,
+				       args->agbno, args->len, &args->oinfo);
+		if (error)
+			goto out_drop_perag;
+	}
+
+	if (!args->wasfromfl) {
+		error = xfs_alloc_update_counters(args->tp, args->agbp,
+						  -((long)(args->len)));
+		if (error)
+			goto out_drop_perag;
+
+		ASSERT(!xfs_extent_busy_search(mp, args->pag, args->agbno,
+				args->len));
+	}
+
+	xfs_ag_resv_alloc_extent(args->pag, args->resv, args);
+
+	XFS_STATS_INC(mp, xs_allocx);
+	XFS_STATS_ADD(mp, xs_allocb, args->len);
+
+out_drop_perag:
+	if (drop_perag && args->pag) {
+		xfs_perag_rele(args->pag);
+		args->pag = NULL;
+	}
+	return error;
+}
+
+/*
+ * Allocate within a single AG only. This uses a best-fit length algorithm so if
+ * you need an exact sized allocation without locality constraints, this is the
+ * fastest way to do it.
+ *
+ * Caller is expected to hold a perag reference in args->pag.
+ */
+int
+xfs_alloc_vextent_this_ag(
+	struct xfs_alloc_arg	*args,
+	xfs_agnumber_t		agno)
+{
+	struct xfs_mount	*mp = args->mp;
+	xfs_agnumber_t		minimum_agno;
+	int			error;
+
+	args->agno = agno;
+	args->agbno = 0;
+	error = xfs_alloc_vextent_check_args(args, XFS_AGB_TO_FSB(mp, agno, 0),
+			&minimum_agno);
+	if (error) {
+		if (error == -ENOSPC)
+			return 0;
+		return error;
+	}
+
+	error = xfs_alloc_vextent_prepare_ag(args);
+	if (!error && args->agbp)
+		error = xfs_alloc_ag_vextent_size(args);
+
+	return xfs_alloc_vextent_finish(args, minimum_agno, error, false);
+}
+
+/*
+ * Iterate all AGs trying to allocate an extent starting from @start_ag.
+ *
+ * If the incoming allocation type is XFS_ALLOCTYPE_NEAR_BNO, it means the
+ * allocation attempts in @start_agno have locality information. If we fail to
+ * allocate in that AG, then we revert to anywhere-in-AG for all the other AGs
+ * we attempt to allocation in as there is no locality optimisation possible for
+ * those allocations.
+ *
+ * On return, args->pag may be left referenced if we finish before the "all
+ * failed" return point. The allocation finish still needs the perag, and
+ * so the caller will release it once they've finished the allocation.
+ *
+ * When we wrap the AG iteration at the end of the filesystem, we have to be
+ * careful not to wrap into AGs below ones we already have locked in the
+ * transaction if we are doing a blocking iteration. This will result in an
+ * out-of-order locking of AGFs and hence can cause deadlocks.
+ */
+static int
+xfs_alloc_vextent_iterate_ags(
+	struct xfs_alloc_arg	*args,
+	xfs_agnumber_t		minimum_agno,
+	xfs_agnumber_t		start_agno,
+	xfs_agblock_t		target_agbno,
+	uint32_t		flags)
+{
+	struct xfs_mount	*mp = args->mp;
+	xfs_agnumber_t		agno;
+	int			error = 0;
+
+restart:
+	for_each_perag_wrap_range(mp, start_agno, minimum_agno,
+			mp->m_sb.sb_agcount, agno, args->pag) {
+		args->agno = agno;
+		error = xfs_alloc_vextent_prepare_ag(args);
+		if (error)
 			break;
+		if (!args->agbp) {
+			trace_xfs_alloc_vextent_loopfailed(args);
+			continue;
 		}
-		args->agbno = XFS_FSB_TO_AGBNO(mp, args->fsbno);
-		if ((error = xfs_alloc_ag_vextent(args)))
-			goto error0;
-		break;
-	case XFS_ALLOCTYPE_START_BNO:
-		/*
-		 * Try near allocation first, then anywhere-in-ag after
-		 * the first a.g. fails.
-		 */
-		if ((args->datatype & XFS_ALLOC_INITIAL_USER_DATA) &&
-		    xfs_is_inode32(mp)) {
-			args->fsbno = XFS_AGB_TO_FSB(mp,
-					((mp->m_agfrotor / rotorstep) %
-					mp->m_sb.sb_agcount), 0);
-			bump_rotor = 1;
-		}
-		args->agbno = XFS_FSB_TO_AGBNO(mp, args->fsbno);
-		args->type = XFS_ALLOCTYPE_NEAR_BNO;
-		fallthrough;
-	case XFS_ALLOCTYPE_FIRST_AG:
+
 		/*
-		 * Rotate through the allocation groups looking for a winner.
+		 * Allocation is supposed to succeed now, so break out of the
+		 * loop regardless of whether we succeed or not.
 		 */
-		if (type == XFS_ALLOCTYPE_FIRST_AG) {
-			/*
-			 * Start with allocation group given by bno.
-			 */
-			args->agno = XFS_FSB_TO_AGNO(mp, args->fsbno);
-			args->type = XFS_ALLOCTYPE_THIS_AG;
-			sagno = 0;
-			flags = 0;
+		if (args->agno == start_agno && target_agbno) {
+			args->agbno = target_agbno;
+			error = xfs_alloc_ag_vextent_near(args);
 		} else {
-			/*
-			 * Start with the given allocation group.
-			 */
-			args->agno = sagno = XFS_FSB_TO_AGNO(mp, args->fsbno);
-			flags = XFS_ALLOC_FLAG_TRYLOCK;
-		}
-		/*
-		 * Loop over allocation groups twice; first time with
-		 * trylock set, second time without.
-		 */
-		for (;;) {
-			args->pag = xfs_perag_get(mp, args->agno);
-			error = xfs_alloc_fix_freelist(args, flags);
-			if (error) {
-				trace_xfs_alloc_vextent_nofix(args);
-				goto error0;
-			}
-			/*
-			 * If we get a buffer back then the allocation will fly.
-			 */
-			if (args->agbp) {
-				if ((error = xfs_alloc_ag_vextent(args)))
-					goto error0;
-				break;
-			}
-
-			trace_xfs_alloc_vextent_loopfailed(args);
-
-			/*
-			 * Didn't work, figure out the next iteration.
-			 */
-			if (args->agno == sagno &&
-			    type == XFS_ALLOCTYPE_START_BNO)
-				args->type = XFS_ALLOCTYPE_THIS_AG;
-			/*
-			* For the first allocation, we can try any AG to get
-			* space.  However, if we already have allocated a
-			* block, we don't want to try AGs whose number is below
-			* sagno. Otherwise, we may end up with out-of-order
-			* locking of AGF, which might cause deadlock.
-			*/
-			if (++(args->agno) == mp->m_sb.sb_agcount) {
-				if (args->tp->t_firstblock != NULLFSBLOCK)
-					args->agno = sagno;
-				else
-					args->agno = 0;
-			}
-			/*
-			 * Reached the starting a.g., must either be done
-			 * or switch to non-trylock mode.
-			 */
-			if (args->agno == sagno) {
-				if (flags == 0) {
-					args->agbno = NULLAGBLOCK;
-					trace_xfs_alloc_vextent_allfailed(args);
-					break;
-				}
-
-				flags = 0;
-				if (type == XFS_ALLOCTYPE_START_BNO) {
-					args->agbno = XFS_FSB_TO_AGBNO(mp,
-						args->fsbno);
-					args->type = XFS_ALLOCTYPE_NEAR_BNO;
-				}
-			}
-			xfs_perag_put(args->pag);
-		}
-		if (bump_rotor) {
-			if (args->agno == sagno)
-				mp->m_agfrotor = (mp->m_agfrotor + 1) %
-					(mp->m_sb.sb_agcount * rotorstep);
-			else
-				mp->m_agfrotor = (args->agno * rotorstep + 1) %
-					(mp->m_sb.sb_agcount * rotorstep);
+			args->agbno = 0;
+			error = xfs_alloc_ag_vextent_size(args);
 		}
 		break;
-	default:
-		ASSERT(0);
-		/* NOTREACHED */
 	}
-	if (args->agbno == NULLAGBLOCK)
-		args->fsbno = NULLFSBLOCK;
-	else {
-		args->fsbno = XFS_AGB_TO_FSB(mp, args->agno, args->agbno);
-#ifdef DEBUG
-		ASSERT(args->len >= args->minlen);
-		ASSERT(args->len <= args->maxlen);
-		ASSERT(args->agbno % args->alignment == 0);
-		XFS_AG_CHECK_DADDR(mp, XFS_FSB_TO_DADDR(mp, args->fsbno),
-			args->len);
-#endif
+	if (error) {
+		xfs_perag_rele(args->pag);
+		args->pag = NULL;
+		return error;
+	}
+	if (args->agbp)
+		return 0;
 
+	/*
+	 * We didn't find an AG we can alloation from. If we were given
+	 * constraining flags by the caller, drop them and retry the allocation
+	 * without any constraints being set.
+	 */
+	if (flags) {
+		flags = 0;
+		goto restart;
 	}
-	xfs_perag_put(args->pag);
+
+	ASSERT(args->pag == NULL);
+	trace_xfs_alloc_vextent_allfailed(args);
 	return 0;
-error0:
-	xfs_perag_put(args->pag);
-	return error;
+}
+
+/*
+ * Iterate from the AGs from the start AG to the end of the filesystem, trying
+ * to allocate blocks. It starts with a near allocation attempt in the initial
+ * AG, then falls back to anywhere-in-ag after the first AG fails. It will wrap
+ * back to zero if allowed by previous allocations in this transaction,
+ * otherwise will wrap back to the start AG and run a second blocking pass to
+ * the end of the filesystem.
+ */
+int
+xfs_alloc_vextent_start_ag(
+	struct xfs_alloc_arg	*args,
+	xfs_fsblock_t		target)
+{
+	struct xfs_mount	*mp = args->mp;
+	xfs_agnumber_t		minimum_agno;
+	xfs_agnumber_t		start_agno;
+	xfs_agnumber_t		rotorstep = xfs_rotorstep;
+	bool			bump_rotor = false;
+	int			error;
+
+	args->agno = NULLAGNUMBER;
+	args->agbno = NULLAGBLOCK;
+	error = xfs_alloc_vextent_check_args(args, target, &minimum_agno);
+	if (error) {
+		if (error == -ENOSPC)
+			return 0;
+		return error;
+	}
+
+	if ((args->datatype & XFS_ALLOC_INITIAL_USER_DATA) &&
+	    xfs_is_inode32(mp)) {
+		target = XFS_AGB_TO_FSB(mp,
+				((mp->m_agfrotor / rotorstep) %
+				mp->m_sb.sb_agcount), 0);
+		bump_rotor = 1;
+	}
+
+	start_agno = max(minimum_agno, XFS_FSB_TO_AGNO(mp, target));
+	error = xfs_alloc_vextent_iterate_ags(args, minimum_agno, start_agno,
+			XFS_FSB_TO_AGBNO(mp, target), XFS_ALLOC_FLAG_TRYLOCK);
+
+	if (bump_rotor) {
+		if (args->agno == start_agno)
+			mp->m_agfrotor = (mp->m_agfrotor + 1) %
+				(mp->m_sb.sb_agcount * rotorstep);
+		else
+			mp->m_agfrotor = (args->agno * rotorstep + 1) %
+				(mp->m_sb.sb_agcount * rotorstep);
+	}
+
+	return xfs_alloc_vextent_finish(args, minimum_agno, error, true);
+}
+
+/*
+ * Iterate from the agno indicated via @target through to the end of the
+ * filesystem attempting blocking allocation. This does not wrap or try a second
+ * pass, so will not recurse into AGs lower than indicated by the target.
+ */
+int
+xfs_alloc_vextent_first_ag(
+	struct xfs_alloc_arg	*args,
+	xfs_fsblock_t		target)
+ {
+	struct xfs_mount	*mp = args->mp;
+	xfs_agnumber_t		minimum_agno;
+	xfs_agnumber_t		start_agno;
+	int			error;
+
+	args->agno = NULLAGNUMBER;
+	args->agbno = NULLAGBLOCK;
+	error = xfs_alloc_vextent_check_args(args, target, &minimum_agno);
+	if (error) {
+		if (error == -ENOSPC)
+			return 0;
+		return error;
+	}
+
+	start_agno = max(minimum_agno, XFS_FSB_TO_AGNO(mp, target));
+	error = xfs_alloc_vextent_iterate_ags(args, minimum_agno, start_agno,
+			XFS_FSB_TO_AGBNO(mp, target), 0);
+	return xfs_alloc_vextent_finish(args, minimum_agno, error, true);
+}
+
+/*
+ * Allocate at the exact block target or fail. Caller is expected to hold a
+ * perag reference in args->pag.
+ */
+int
+xfs_alloc_vextent_exact_bno(
+	struct xfs_alloc_arg	*args,
+	xfs_fsblock_t		target)
+{
+	struct xfs_mount	*mp = args->mp;
+	xfs_agnumber_t		minimum_agno;
+	int			error;
+
+	args->agno = XFS_FSB_TO_AGNO(mp, target);
+	args->agbno = XFS_FSB_TO_AGBNO(mp, target);
+	error = xfs_alloc_vextent_check_args(args, target, &minimum_agno);
+	if (error) {
+		if (error == -ENOSPC)
+			return 0;
+		return error;
+	}
+
+	error = xfs_alloc_vextent_prepare_ag(args);
+	if (!error && args->agbp)
+		error = xfs_alloc_ag_vextent_exact(args);
+
+	return xfs_alloc_vextent_finish(args, minimum_agno, error, false);
+}
+
+/*
+ * Allocate an extent as close to the target as possible. If there are not
+ * viable candidates in the AG, then fail the allocation.
+ *
+ * Caller may or may not have a per-ag reference in args->pag.
+ */
+int
+xfs_alloc_vextent_near_bno(
+	struct xfs_alloc_arg	*args,
+	xfs_fsblock_t		target)
+{
+	struct xfs_mount	*mp = args->mp;
+	xfs_agnumber_t		minimum_agno;
+	bool			needs_perag = args->pag == NULL;
+	int			error;
+
+	args->agno = XFS_FSB_TO_AGNO(mp, target);
+	args->agbno = XFS_FSB_TO_AGBNO(mp, target);
+	error = xfs_alloc_vextent_check_args(args, target, &minimum_agno);
+	if (error) {
+		if (error == -ENOSPC)
+			return 0;
+		return error;
+	}
+
+	if (needs_perag)
+		args->pag = xfs_perag_grab(mp, args->agno);
+
+	error = xfs_alloc_vextent_prepare_ag(args);
+	if (!error && args->agbp)
+		error = xfs_alloc_ag_vextent_near(args);
+
+	return xfs_alloc_vextent_finish(args, minimum_agno, error, needs_perag);
 }
 
 /* Ensure that the freelist is at full capacity. */
diff --git a/fs/xfs/libxfs/xfs_alloc.h b/fs/xfs/libxfs/xfs_alloc.h
index 2c3f762dfb5818..2b246d74c18901 100644
--- a/fs/xfs/libxfs/xfs_alloc.h
+++ b/fs/xfs/libxfs/xfs_alloc.h
@@ -17,25 +17,6 @@ extern struct workqueue_struct *xfs_alloc_wq;
 unsigned int xfs_agfl_size(struct xfs_mount *mp);
 
 /*
- * Freespace allocation types.  Argument to xfs_alloc_[v]extent.
- */
-#define XFS_ALLOCTYPE_FIRST_AG	0x02	/* ... start at ag 0 */
-#define XFS_ALLOCTYPE_THIS_AG	0x08	/* anywhere in this a.g. */
-#define XFS_ALLOCTYPE_START_BNO	0x10	/* near this block else anywhere */
-#define XFS_ALLOCTYPE_NEAR_BNO	0x20	/* in this a.g. and near this block */
-#define XFS_ALLOCTYPE_THIS_BNO	0x40	/* at exactly this block */
-
-/* this should become an enum again when the tracing code is fixed */
-typedef unsigned int xfs_alloctype_t;
-
-#define XFS_ALLOC_TYPES \
-	{ XFS_ALLOCTYPE_FIRST_AG,	"FIRST_AG" }, \
-	{ XFS_ALLOCTYPE_THIS_AG,	"THIS_AG" }, \
-	{ XFS_ALLOCTYPE_START_BNO,	"START_BNO" }, \
-	{ XFS_ALLOCTYPE_NEAR_BNO,	"NEAR_BNO" }, \
-	{ XFS_ALLOCTYPE_THIS_BNO,	"THIS_BNO" }
-
-/*
  * Flags for xfs_alloc_fix_freelist.
  */
 #define	XFS_ALLOC_FLAG_TRYLOCK	0x00000001  /* use trylock for buffer locking */
@@ -68,8 +49,6 @@ typedef struct xfs_alloc_arg {
 	xfs_agblock_t	min_agbno;	/* set an agbno range for NEAR allocs */
 	xfs_agblock_t	max_agbno;	/* ... */
 	xfs_extlen_t	len;		/* output: actual size of extent */
-	xfs_alloctype_t	type;		/* allocation type XFS_ALLOCTYPE_... */
-	xfs_alloctype_t	otype;		/* original allocation type */
 	int		datatype;	/* mask defining data type treatment */
 	char		wasdel;		/* set if allocation was prev delayed */
 	char		wasfromfl;	/* set if allocation is from freelist */
@@ -118,11 +97,43 @@ xfs_alloc_log_agf(
 	uint32_t	fields);/* mask of fields to be logged (XFS_AGF_...) */
 
 /*
- * Allocate an extent (variable-size).
+ * Allocate an extent anywhere in the specific AG given. If there is no
+ * space matching the requirements in that AG, then the allocation will fail.
  */
-int				/* error */
-xfs_alloc_vextent(
-	xfs_alloc_arg_t	*args);	/* allocation argument structure */
+int xfs_alloc_vextent_this_ag(struct xfs_alloc_arg *args, xfs_agnumber_t agno);
+
+/*
+ * Allocate an extent as close to the target as possible. If there are not
+ * viable candidates in the AG, then fail the allocation.
+ */
+int xfs_alloc_vextent_near_bno(struct xfs_alloc_arg *args,
+		xfs_fsblock_t target);
+
+/*
+ * Allocate an extent exactly at the target given. If this is not possible
+ * then the allocation fails.
+ */
+int xfs_alloc_vextent_exact_bno(struct xfs_alloc_arg *args,
+		xfs_fsblock_t target);
+
+/*
+ * Best effort full filesystem allocation scan.
+ *
+ * Locality aware allocation will be attempted in the initial AG, but on failure
+ * non-localised attempts will be made. The AGs are constrained by previous
+ * allocations in the current transaction. Two passes will be made - the first
+ * non-blocking, the second blocking.
+ */
+int xfs_alloc_vextent_start_ag(struct xfs_alloc_arg *args,
+		xfs_fsblock_t target);
+
+/*
+ * Iterate from the AG indicated from args->fsbno through to the end of the
+ * filesystem attempting blocking allocation. This is for use in last
+ * resort allocation attempts when everything else has failed.
+ */
+int xfs_alloc_vextent_first_ag(struct xfs_alloc_arg *args,
+		xfs_fsblock_t target);
 
 /*
  * Free an extent.
diff --git a/fs/xfs/libxfs/xfs_alloc_btree.c b/fs/xfs/libxfs/xfs_alloc_btree.c
index 549a3cba0234de..0f29c7b1b39f32 100644
--- a/fs/xfs/libxfs/xfs_alloc_btree.c
+++ b/fs/xfs/libxfs/xfs_alloc_btree.c
@@ -315,7 +315,7 @@ xfs_allocbt_verify(
 	level = be16_to_cpu(block->bb_level);
 	if (bp->b_ops->magic[0] == cpu_to_be32(XFS_ABTC_MAGIC))
 		btnum = XFS_BTNUM_CNTi;
-	if (pag && pag->pagf_init) {
+	if (pag && xfs_perag_initialised_agf(pag)) {
 		if (level >= pag->pagf_levels[btnum])
 			return __this_address;
 	} else if (level >= mp->m_alloc_maxlevels)
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index c8c65387136c9d..34de6e6898c480 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -645,34 +645,23 @@ xfs_bmap_extents_to_btree(
 	args.tp = tp;
 	args.mp = mp;
 	xfs_rmap_ino_bmbt_owner(&args.oinfo, ip->i_ino, whichfork);
-	if (tp->t_firstblock == NULLFSBLOCK) {
-		args.type = XFS_ALLOCTYPE_START_BNO;
-		args.fsbno = XFS_INO_TO_FSB(mp, ip->i_ino);
-	} else if (tp->t_flags & XFS_TRANS_LOWMODE) {
-		args.type = XFS_ALLOCTYPE_START_BNO;
-		args.fsbno = tp->t_firstblock;
-	} else {
-		args.type = XFS_ALLOCTYPE_NEAR_BNO;
-		args.fsbno = tp->t_firstblock;
-	}
+
 	args.minlen = args.maxlen = args.prod = 1;
 	args.wasdel = wasdel;
 	*logflagsp = 0;
-	error = xfs_alloc_vextent(&args);
+	error = xfs_alloc_vextent_start_ag(&args,
+				XFS_INO_TO_FSB(mp, ip->i_ino));
 	if (error)
 		goto out_root_realloc;
 
+	/*
+	 * Allocation can't fail, the space was reserved.
+	 */
 	if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
 		error = -ENOSPC;
 		goto out_root_realloc;
 	}
 
-	/*
-	 * Allocation can't fail, the space was reserved.
-	 */
-	ASSERT(tp->t_firstblock == NULLFSBLOCK ||
-	       args.agno >= XFS_FSB_TO_AGNO(mp, tp->t_firstblock));
-	tp->t_firstblock = args.fsbno;
 	cur->bc_ino.allocated++;
 	ip->i_nblocks++;
 	xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, 1L);
@@ -799,28 +788,24 @@ xfs_bmap_local_to_extents(
 	memset(&args, 0, sizeof(args));
 	args.tp = tp;
 	args.mp = ip->i_mount;
+	args.total = total;
+	args.minlen = args.maxlen = args.prod = 1;
 	xfs_rmap_ino_owner(&args.oinfo, ip->i_ino, whichfork, 0);
+
 	/*
 	 * Allocate a block.  We know we need only one, since the
 	 * file currently fits in an inode.
 	 */
-	if (tp->t_firstblock == NULLFSBLOCK) {
-		args.fsbno = XFS_INO_TO_FSB(args.mp, ip->i_ino);
-		args.type = XFS_ALLOCTYPE_START_BNO;
-	} else {
-		args.fsbno = tp->t_firstblock;
-		args.type = XFS_ALLOCTYPE_NEAR_BNO;
-	}
 	args.total = total;
 	args.minlen = args.maxlen = args.prod = 1;
-	error = xfs_alloc_vextent(&args);
+	error = xfs_alloc_vextent_start_ag(&args,
+			XFS_INO_TO_FSB(args.mp, ip->i_ino));
 	if (error)
 		goto done;
 
 	/* Can't fail, the space was reserved. */
 	ASSERT(args.fsbno != NULLFSBLOCK);
 	ASSERT(args.len == 1);
-	tp->t_firstblock = args.fsbno;
 	error = xfs_trans_get_buf(tp, args.mp->m_ddev_targp,
 			XFS_FSB_TO_DADDR(args.mp, args.fsbno),
 			args.mp->m_bsize, 0, &bp);
@@ -854,8 +839,7 @@ xfs_bmap_local_to_extents(
 
 	ifp->if_nextents = 1;
 	ip->i_nblocks = 1;
-	xfs_trans_mod_dquot_byino(tp, ip,
-		XFS_TRANS_DQ_BCOUNT, 1L);
+	xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, 1L);
 	flags |= xfs_ilog_fext(whichfork);
 
 done:
@@ -3025,9 +3009,7 @@ xfs_bmap_adjacent(
 	struct xfs_bmalloca	*ap)	/* bmap alloc argument struct */
 {
 	xfs_fsblock_t	adjust;		/* adjustment to block numbers */
-	xfs_agnumber_t	fb_agno;	/* ag number of ap->firstblock */
 	xfs_mount_t	*mp;		/* mount point structure */
-	int		nullfb;		/* true if ap->firstblock isn't set */
 	int		rt;		/* true if inode is realtime */
 
 #define	ISVALID(x,y)	\
@@ -3038,11 +3020,8 @@ xfs_bmap_adjacent(
 		XFS_FSB_TO_AGBNO(mp, x) < mp->m_sb.sb_agblocks)
 
 	mp = ap->ip->i_mount;
-	nullfb = ap->tp->t_firstblock == NULLFSBLOCK;
 	rt = XFS_IS_REALTIME_INODE(ap->ip) &&
 		(ap->datatype & XFS_ALLOC_USERDATA);
-	fb_agno = nullfb ? NULLAGNUMBER : XFS_FSB_TO_AGNO(mp,
-							ap->tp->t_firstblock);
 	/*
 	 * If allocating at eof, and there's a previous real block,
 	 * try to use its last block as our starting point.
@@ -3101,13 +3080,6 @@ xfs_bmap_adjacent(
 				prevbno += adjust;
 			else
 				prevdiff += adjust;
-			/*
-			 * If the firstblock forbids it, can't use it,
-			 * must use default.
-			 */
-			if (!rt && !nullfb &&
-			    XFS_FSB_TO_AGNO(mp, prevbno) != fb_agno)
-				prevbno = NULLFSBLOCK;
 		}
 		/*
 		 * No previous block or can't follow it, just default.
@@ -3143,13 +3115,6 @@ xfs_bmap_adjacent(
 				gotdiff += adjust - ap->length;
 			} else
 				gotdiff += adjust;
-			/*
-			 * If the firstblock forbids it, can't use it,
-			 * must use default.
-			 */
-			if (!rt && !nullfb &&
-			    XFS_FSB_TO_AGNO(mp, gotbno) != fb_agno)
-				gotbno = NULLFSBLOCK;
 		}
 		/*
 		 * No next block, just default.
@@ -3170,147 +3135,91 @@ xfs_bmap_adjacent(
 #undef ISVALID
 }
 
-static int
+int
 xfs_bmap_longest_free_extent(
+	struct xfs_perag	*pag,
 	struct xfs_trans	*tp,
-	xfs_agnumber_t		ag,
-	xfs_extlen_t		*blen,
-	int			*notinit)
+	xfs_extlen_t		*blen)
 {
-	struct xfs_mount	*mp = tp->t_mountp;
-	struct xfs_perag	*pag;
 	xfs_extlen_t		longest;
 	int			error = 0;
 
-	pag = xfs_perag_get(mp, ag);
-	if (!pag->pagf_init) {
+	if (!xfs_perag_initialised_agf(pag)) {
 		error = xfs_alloc_read_agf(pag, tp, XFS_ALLOC_FLAG_TRYLOCK,
 				NULL);
-		if (error) {
-			/* Couldn't lock the AGF, so skip this AG. */
-			if (error == -EAGAIN) {
-				*notinit = 1;
-				error = 0;
-			}
-			goto out;
-		}
+		if (error)
+			return error;
 	}
 
 	longest = xfs_alloc_longest_free_extent(pag,
-				xfs_alloc_min_freelist(mp, pag),
+				xfs_alloc_min_freelist(pag->pag_mount, pag),
 				xfs_ag_resv_needed(pag, XFS_AG_RESV_NONE));
 	if (*blen < longest)
 		*blen = longest;
 
-out:
-	xfs_perag_put(pag);
-	return error;
+	return 0;
 }
 
-static void
+static xfs_extlen_t
 xfs_bmap_select_minlen(
 	struct xfs_bmalloca	*ap,
 	struct xfs_alloc_arg	*args,
-	xfs_extlen_t		*blen,
-	int			notinit)
+	xfs_extlen_t		blen)
 {
-	if (notinit || *blen < ap->minlen) {
-		/*
-		 * Since we did a BUF_TRYLOCK above, it is possible that
-		 * there is space for this request.
-		 */
-		args->minlen = ap->minlen;
-	} else if (*blen < args->maxlen) {
-		/*
-		 * If the best seen length is less than the request length,
-		 * use the best as the minimum.
-		 */
-		args->minlen = *blen;
-	} else {
-		/*
-		 * Otherwise we've seen an extent as big as maxlen, use that
-		 * as the minimum.
-		 */
-		args->minlen = args->maxlen;
-	}
-}
-
-STATIC int
-xfs_bmap_btalloc_nullfb(
-	struct xfs_bmalloca	*ap,
-	struct xfs_alloc_arg	*args,
-	xfs_extlen_t		*blen)
-{
-	struct xfs_mount	*mp = ap->ip->i_mount;
-	xfs_agnumber_t		ag, startag;
-	int			notinit = 0;
-	int			error;
 
-	args->type = XFS_ALLOCTYPE_START_BNO;
-	args->total = ap->total;
-
-	startag = ag = XFS_FSB_TO_AGNO(mp, args->fsbno);
-	if (startag == NULLAGNUMBER)
-		startag = ag = 0;
-
-	while (*blen < args->maxlen) {
-		error = xfs_bmap_longest_free_extent(args->tp, ag, blen,
-						     &notinit);
-		if (error)
-			return error;
-
-		if (++ag == mp->m_sb.sb_agcount)
-			ag = 0;
-		if (ag == startag)
-			break;
-	}
+	/*
+	 * Since we used XFS_ALLOC_FLAG_TRYLOCK in _longest_free_extent(), it is
+	 * possible that there is enough contiguous free space for this request.
+	 */
+	if (blen < ap->minlen)
+		return ap->minlen;
 
-	xfs_bmap_select_minlen(ap, args, blen, notinit);
-	return 0;
+	/*
+	 * If the best seen length is less than the request length,
+	 * use the best as the minimum, otherwise we've got the maxlen we
+	 * were asked for.
+	 */
+	if (blen < args->maxlen)
+		return blen;
+	return args->maxlen;
 }
 
-STATIC int
-xfs_bmap_btalloc_filestreams(
+static int
+xfs_bmap_btalloc_select_lengths(
 	struct xfs_bmalloca	*ap,
 	struct xfs_alloc_arg	*args,
 	xfs_extlen_t		*blen)
 {
-	struct xfs_mount	*mp = ap->ip->i_mount;
-	xfs_agnumber_t		ag;
-	int			notinit = 0;
-	int			error;
-
-	args->type = XFS_ALLOCTYPE_NEAR_BNO;
-	args->total = ap->total;
-
-	ag = XFS_FSB_TO_AGNO(mp, args->fsbno);
-	if (ag == NULLAGNUMBER)
-		ag = 0;
-
-	error = xfs_bmap_longest_free_extent(args->tp, ag, blen, &notinit);
-	if (error)
-		return error;
+	struct xfs_mount	*mp = args->mp;
+	struct xfs_perag	*pag;
+	xfs_agnumber_t		agno, startag;
+	int			error = 0;
 
-	if (*blen < args->maxlen) {
-		error = xfs_filestream_new_ag(ap, &ag);
-		if (error)
-			return error;
+	if (ap->tp->t_flags & XFS_TRANS_LOWMODE) {
+		args->total = ap->minlen;
+		args->minlen = ap->minlen;
+		return 0;
+	}
 
-		error = xfs_bmap_longest_free_extent(args->tp, ag, blen,
-						     &notinit);
-		if (error)
-			return error;
+	args->total = ap->total;
+	startag = XFS_FSB_TO_AGNO(mp, ap->blkno);
+	if (startag == NULLAGNUMBER)
+		startag = 0;
 
+	*blen = 0;
+	for_each_perag_wrap(mp, startag, agno, pag) {
+		error = xfs_bmap_longest_free_extent(pag, args->tp, blen);
+		if (error && error != -EAGAIN)
+			break;
+		error = 0;
+		if (*blen >= args->maxlen)
+			break;
 	}
+	if (pag)
+		xfs_perag_rele(pag);
 
-	xfs_bmap_select_minlen(ap, args, blen, notinit);
-
-	/*
-	 * Set the failure fallback case to look in the selected AG as stream
-	 * may have moved.
-	 */
-	ap->blkno = args->fsbno = XFS_AGB_TO_FSB(mp, ag, 0);
-	return 0;
+	args->minlen = xfs_bmap_select_minlen(ap, args, *blen);
+	return error;
 }
 
 /* Update all inode and quota accounting for the allocation we just did. */
@@ -3413,21 +3322,7 @@ xfs_bmap_process_allocated_extent(
 	xfs_fileoff_t		orig_offset,
 	xfs_extlen_t		orig_length)
 {
-	int			nullfb;
-
-	nullfb = ap->tp->t_firstblock == NULLFSBLOCK;
-
-	/*
-	 * check the allocation happened at the same or higher AG than
-	 * the first block that was allocated.
-	 */
-	ASSERT(nullfb ||
-		XFS_FSB_TO_AGNO(args->mp, ap->tp->t_firstblock) <=
-		XFS_FSB_TO_AGNO(args->mp, args->fsbno));
-
 	ap->blkno = args->fsbno;
-	if (nullfb)
-		ap->tp->t_firstblock = args->fsbno;
 	ap->length = args->len;
 	/*
 	 * If the extent size hint is active, we tried to round the
@@ -3474,23 +3369,17 @@ xfs_bmap_exact_minlen_extent_alloc(
 
 	xfs_bmap_compute_alignments(ap, &args);
 
-	if (ap->tp->t_firstblock == NULLFSBLOCK) {
-		/*
-		 * Unlike the longest extent available in an AG, we don't track
-		 * the length of an AG's shortest extent.
-		 * XFS_ERRTAG_BMAP_ALLOC_MINLEN_EXTENT is a debug only knob and
-		 * hence we can afford to start traversing from the 0th AG since
-		 * we need not be concerned about a drop in performance in
-		 * "debug only" code paths.
-		 */
-		ap->blkno = XFS_AGB_TO_FSB(mp, 0, 0);
-	} else {
-		ap->blkno = ap->tp->t_firstblock;
-	}
+	/*
+	 * Unlike the longest extent available in an AG, we don't track
+	 * the length of an AG's shortest extent.
+	 * XFS_ERRTAG_BMAP_ALLOC_MINLEN_EXTENT is a debug only knob and
+	 * hence we can afford to start traversing from the 0th AG since
+	 * we need not be concerned about a drop in performance in
+	 * "debug only" code paths.
+	 */
+	ap->blkno = XFS_AGB_TO_FSB(mp, 0, 0);
 
-	args.fsbno = ap->blkno;
 	args.oinfo = XFS_RMAP_OINFO_SKIP_UPDATE;
-	args.type = XFS_ALLOCTYPE_FIRST_AG;
 	args.minlen = args.maxlen = ap->minlen;
 	args.total = ap->total;
 
@@ -3502,7 +3391,7 @@ xfs_bmap_exact_minlen_extent_alloc(
 	args.resv = XFS_AG_RESV_NONE;
 	args.datatype = ap->datatype;
 
-	error = xfs_alloc_vextent(&args);
+	error = xfs_alloc_vextent_first_ag(&args, ap->blkno);
 	if (error)
 		return error;
 
@@ -3522,193 +3411,270 @@ xfs_bmap_exact_minlen_extent_alloc(
 
 #endif
 
-STATIC int
-xfs_bmap_btalloc(
-	struct xfs_bmalloca	*ap)
+/*
+ * If we are not low on available data blocks and we are allocating at
+ * EOF, optimise allocation for contiguous file extension and/or stripe
+ * alignment of the new extent.
+ *
+ * NOTE: ap->aeof is only set if the allocation length is >= the
+ * stripe unit and the allocation offset is at the end of file.
+ */
+static int
+xfs_bmap_btalloc_at_eof(
+	struct xfs_bmalloca	*ap,
+	struct xfs_alloc_arg	*args,
+	xfs_extlen_t		blen,
+	int			stripe_align,
+	bool			ag_only)
 {
-	struct xfs_mount	*mp = ap->ip->i_mount;
-	struct xfs_alloc_arg	args = { .tp = ap->tp, .mp = mp };
-	xfs_alloctype_t		atype = 0;
-	xfs_agnumber_t		fb_agno;	/* ag number of ap->firstblock */
-	xfs_agnumber_t		ag;
-	xfs_fileoff_t		orig_offset;
-	xfs_extlen_t		orig_length;
-	xfs_extlen_t		blen;
-	xfs_extlen_t		nextminlen = 0;
-	int			nullfb; /* true if ap->firstblock isn't set */
-	int			isaligned;
-	int			tryagain;
+	struct xfs_mount	*mp = args->mp;
+	struct xfs_perag	*caller_pag = args->pag;
 	int			error;
-	int			stripe_align;
-
-	ASSERT(ap->length);
-	orig_offset = ap->offset;
-	orig_length = ap->length;
-
-	stripe_align = xfs_bmap_compute_alignments(ap, &args);
-
-	nullfb = ap->tp->t_firstblock == NULLFSBLOCK;
-	fb_agno = nullfb ? NULLAGNUMBER : XFS_FSB_TO_AGNO(mp,
-							ap->tp->t_firstblock);
-	if (nullfb) {
-		if ((ap->datatype & XFS_ALLOC_USERDATA) &&
-		    xfs_inode_is_filestream(ap->ip)) {
-			ag = xfs_filestream_lookup_ag(ap->ip);
-			ag = (ag != NULLAGNUMBER) ? ag : 0;
-			ap->blkno = XFS_AGB_TO_FSB(mp, ag, 0);
-		} else {
-			ap->blkno = XFS_INO_TO_FSB(mp, ap->ip->i_ino);
-		}
-	} else
-		ap->blkno = ap->tp->t_firstblock;
 
-	xfs_bmap_adjacent(ap);
-
-	/*
-	 * If allowed, use ap->blkno; otherwise must use firstblock since
-	 * it's in the right allocation group.
-	 */
-	if (nullfb || XFS_FSB_TO_AGNO(mp, ap->blkno) == fb_agno)
-		;
-	else
-		ap->blkno = ap->tp->t_firstblock;
 	/*
-	 * Normal allocation, done through xfs_alloc_vextent.
+	 * If there are already extents in the file, try an exact EOF block
+	 * allocation to extend the file as a contiguous extent. If that fails,
+	 * or it's the first allocation in a file, just try for a stripe aligned
+	 * allocation.
 	 */
-	tryagain = isaligned = 0;
-	args.fsbno = ap->blkno;
-	args.oinfo = XFS_RMAP_OINFO_SKIP_UPDATE;
+	if (ap->offset) {
+		xfs_extlen_t	nextminlen = 0;
 
-	/* Trim the allocation back to the maximum an AG can fit. */
-	args.maxlen = min(ap->length, mp->m_ag_max_usable);
-	blen = 0;
-	if (nullfb) {
 		/*
-		 * Search for an allocation group with a single extent large
-		 * enough for the request.  If one isn't found, then adjust
-		 * the minimum allocation size to the largest space found.
+		 * Compute the minlen+alignment for the next case.  Set slop so
+		 * that the value of minlen+alignment+slop doesn't go up between
+		 * the calls.
 		 */
-		if ((ap->datatype & XFS_ALLOC_USERDATA) &&
-		    xfs_inode_is_filestream(ap->ip))
-			error = xfs_bmap_btalloc_filestreams(ap, &args, &blen);
+		args->alignment = 1;
+		if (blen > stripe_align && blen <= args->maxlen)
+			nextminlen = blen - stripe_align;
+		else
+			nextminlen = args->minlen;
+		if (nextminlen + stripe_align > args->minlen + 1)
+			args->minalignslop = nextminlen + stripe_align -
+					args->minlen - 1;
 		else
-			error = xfs_bmap_btalloc_nullfb(ap, &args, &blen);
+			args->minalignslop = 0;
+
+		if (!caller_pag)
+			args->pag = xfs_perag_get(mp, XFS_FSB_TO_AGNO(mp, ap->blkno));
+		error = xfs_alloc_vextent_exact_bno(args, ap->blkno);
+		if (!caller_pag)
+			xfs_perag_put(args->pag);
 		if (error)
 			return error;
-	} else if (ap->tp->t_flags & XFS_TRANS_LOWMODE) {
-		if (xfs_inode_is_filestream(ap->ip))
-			args.type = XFS_ALLOCTYPE_FIRST_AG;
-		else
-			args.type = XFS_ALLOCTYPE_START_BNO;
-		args.total = args.minlen = ap->minlen;
+
+		if (args->fsbno != NULLFSBLOCK)
+			return 0;
+		/*
+		 * Exact allocation failed. Reset to try an aligned allocation
+		 * according to the original allocation specification.
+		 */
+		args->pag = NULL;
+		args->alignment = stripe_align;
+		args->minlen = nextminlen;
+		args->minalignslop = 0;
 	} else {
-		args.type = XFS_ALLOCTYPE_NEAR_BNO;
-		args.total = ap->total;
-		args.minlen = ap->minlen;
+		/*
+		 * Adjust minlen to try and preserve alignment if we
+		 * can't guarantee an aligned maxlen extent.
+		 */
+		args->alignment = stripe_align;
+		if (blen > args->alignment &&
+		    blen <= args->maxlen + args->alignment)
+			args->minlen = blen - args->alignment;
+		args->minalignslop = 0;
 	}
 
-	/*
-	 * If we are not low on available data blocks, and the underlying
-	 * logical volume manager is a stripe, and the file offset is zero then
-	 * try to allocate data blocks on stripe unit boundary. NOTE: ap->aeof
-	 * is only set if the allocation length is >= the stripe unit and the
-	 * allocation offset is at the end of file.
-	 */
-	if (!(ap->tp->t_flags & XFS_TRANS_LOWMODE) && ap->aeof) {
-		if (!ap->offset) {
-			args.alignment = stripe_align;
-			atype = args.type;
-			isaligned = 1;
-			/*
-			 * Adjust minlen to try and preserve alignment if we
-			 * can't guarantee an aligned maxlen extent.
-			 */
-			if (blen > args.alignment &&
-			    blen <= args.maxlen + args.alignment)
-				args.minlen = blen - args.alignment;
-			args.minalignslop = 0;
-		} else {
-			/*
-			 * First try an exact bno allocation.
-			 * If it fails then do a near or start bno
-			 * allocation with alignment turned on.
-			 */
-			atype = args.type;
-			tryagain = 1;
-			args.type = XFS_ALLOCTYPE_THIS_BNO;
-			args.alignment = 1;
-			/*
-			 * Compute the minlen+alignment for the
-			 * next case.  Set slop so that the value
-			 * of minlen+alignment+slop doesn't go up
-			 * between the calls.
-			 */
-			if (blen > stripe_align && blen <= args.maxlen)
-				nextminlen = blen - stripe_align;
-			else
-				nextminlen = args.minlen;
-			if (nextminlen + stripe_align > args.minlen + 1)
-				args.minalignslop =
-					nextminlen + stripe_align -
-					args.minlen - 1;
-			else
-				args.minalignslop = 0;
-		}
+	if (ag_only) {
+		error = xfs_alloc_vextent_near_bno(args, ap->blkno);
 	} else {
-		args.alignment = 1;
-		args.minalignslop = 0;
+		args->pag = NULL;
+		error = xfs_alloc_vextent_start_ag(args, ap->blkno);
+		ASSERT(args->pag == NULL);
+		args->pag = caller_pag;
 	}
-	args.minleft = ap->minleft;
-	args.wasdel = ap->wasdel;
-	args.resv = XFS_AG_RESV_NONE;
-	args.datatype = ap->datatype;
-
-	error = xfs_alloc_vextent(&args);
 	if (error)
 		return error;
 
-	if (tryagain && args.fsbno == NULLFSBLOCK) {
-		/*
-		 * Exact allocation failed. Now try with alignment
-		 * turned on.
-		 */
-		args.type = atype;
-		args.fsbno = ap->blkno;
-		args.alignment = stripe_align;
-		args.minlen = nextminlen;
-		args.minalignslop = 0;
-		isaligned = 1;
-		if ((error = xfs_alloc_vextent(&args)))
-			return error;
-	}
-	if (isaligned && args.fsbno == NULLFSBLOCK) {
-		/*
-		 * allocation failed, so turn off alignment and
-		 * try again.
-		 */
-		args.type = atype;
-		args.fsbno = ap->blkno;
-		args.alignment = 0;
-		if ((error = xfs_alloc_vextent(&args)))
+	if (args->fsbno != NULLFSBLOCK)
+		return 0;
+
+	/*
+	 * Allocation failed, so turn return the allocation args to their
+	 * original non-aligned state so the caller can proceed on allocation
+	 * failure as if this function was never called.
+	 */
+	args->fsbno = ap->blkno;
+	args->alignment = 1;
+	return 0;
+}
+
+/*
+ * We have failed multiple allocation attempts so now are in a low space
+ * allocation situation. Try a locality first full filesystem minimum length
+ * allocation whilst still maintaining necessary total block reservation
+ * requirements.
+ *
+ * If that fails, we are now critically low on space, so perform a last resort
+ * allocation attempt: no reserve, no locality, blocking, minimum length, full
+ * filesystem free space scan. We also indicate to future allocations in this
+ * transaction that we are critically low on space so they don't waste time on
+ * allocation modes that are unlikely to succeed.
+ */
+int
+xfs_bmap_btalloc_low_space(
+	struct xfs_bmalloca	*ap,
+	struct xfs_alloc_arg	*args)
+{
+	int			error;
+
+	if (args->minlen > ap->minlen) {
+		args->minlen = ap->minlen;
+		error = xfs_alloc_vextent_start_ag(args, ap->blkno);
+		if (error || args->fsbno != NULLFSBLOCK)
 			return error;
 	}
-	if (args.fsbno == NULLFSBLOCK && nullfb &&
-	    args.minlen > ap->minlen) {
-		args.minlen = ap->minlen;
-		args.type = XFS_ALLOCTYPE_START_BNO;
-		args.fsbno = ap->blkno;
-		if ((error = xfs_alloc_vextent(&args)))
-			return error;
+
+	/* Last ditch attempt before failure is declared. */
+	args->total = ap->minlen;
+	error = xfs_alloc_vextent_first_ag(args, 0);
+	if (error)
+		return error;
+	ap->tp->t_flags |= XFS_TRANS_LOWMODE;
+	return 0;
+}
+
+static int
+xfs_bmap_btalloc_filestreams(
+	struct xfs_bmalloca	*ap,
+	struct xfs_alloc_arg	*args,
+	int			stripe_align)
+{
+	xfs_extlen_t		blen = 0;
+	int			error = 0;
+
+
+	error = xfs_filestream_select_ag(ap, args, &blen);
+	if (error)
+		return error;
+	ASSERT(args->pag);
+
+	/*
+	 * If we are in low space mode, then optimal allocation will fail so
+	 * prepare for minimal allocation and jump to the low space algorithm
+	 * immediately.
+	 */
+	if (ap->tp->t_flags & XFS_TRANS_LOWMODE) {
+		args->minlen = ap->minlen;
+		ASSERT(args->fsbno == NULLFSBLOCK);
+		goto out_low_space;
 	}
-	if (args.fsbno == NULLFSBLOCK && nullfb) {
-		args.fsbno = 0;
-		args.type = XFS_ALLOCTYPE_FIRST_AG;
-		args.total = ap->minlen;
-		if ((error = xfs_alloc_vextent(&args)))
+
+	args->minlen = xfs_bmap_select_minlen(ap, args, blen);
+	if (ap->aeof)
+		error = xfs_bmap_btalloc_at_eof(ap, args, blen, stripe_align,
+				true);
+
+	if (!error && args->fsbno == NULLFSBLOCK)
+		error = xfs_alloc_vextent_near_bno(args, ap->blkno);
+
+out_low_space:
+	/*
+	 * We are now done with the perag reference for the filestreams
+	 * association provided by xfs_filestream_select_ag(). Release it now as
+	 * we've either succeeded, had a fatal error or we are out of space and
+	 * need to do a full filesystem scan for free space which will take it's
+	 * own references.
+	 */
+	xfs_perag_rele(args->pag);
+	args->pag = NULL;
+	if (error || args->fsbno != NULLFSBLOCK)
+		return error;
+
+	return xfs_bmap_btalloc_low_space(ap, args);
+}
+
+static int
+xfs_bmap_btalloc_best_length(
+	struct xfs_bmalloca	*ap,
+	struct xfs_alloc_arg	*args,
+	int			stripe_align)
+{
+	xfs_extlen_t		blen = 0;
+	int			error;
+
+	ap->blkno = XFS_INO_TO_FSB(args->mp, ap->ip->i_ino);
+	xfs_bmap_adjacent(ap);
+
+	/*
+	 * Search for an allocation group with a single extent large enough for
+	 * the request.  If one isn't found, then adjust the minimum allocation
+	 * size to the largest space found.
+	 */
+	error = xfs_bmap_btalloc_select_lengths(ap, args, &blen);
+	if (error)
+		return error;
+
+	/*
+	 * Don't attempt optimal EOF allocation if previous allocations barely
+	 * succeeded due to being near ENOSPC. It is highly unlikely we'll get
+	 * optimal or even aligned allocations in this case, so don't waste time
+	 * trying.
+	 */
+	if (ap->aeof && !(ap->tp->t_flags & XFS_TRANS_LOWMODE)) {
+		error = xfs_bmap_btalloc_at_eof(ap, args, blen, stripe_align,
+				false);
+		if (error || args->fsbno != NULLFSBLOCK)
 			return error;
-		ap->tp->t_flags |= XFS_TRANS_LOWMODE;
 	}
 
+	error = xfs_alloc_vextent_start_ag(args, ap->blkno);
+	if (error || args->fsbno != NULLFSBLOCK)
+		return error;
+
+	return xfs_bmap_btalloc_low_space(ap, args);
+}
+
+static int
+xfs_bmap_btalloc(
+	struct xfs_bmalloca	*ap)
+{
+	struct xfs_mount	*mp = ap->ip->i_mount;
+	struct xfs_alloc_arg	args = {
+		.tp		= ap->tp,
+		.mp		= mp,
+		.fsbno		= NULLFSBLOCK,
+		.oinfo		= XFS_RMAP_OINFO_SKIP_UPDATE,
+		.minleft	= ap->minleft,
+		.wasdel		= ap->wasdel,
+		.resv		= XFS_AG_RESV_NONE,
+		.datatype	= ap->datatype,
+		.alignment	= 1,
+		.minalignslop	= 0,
+	};
+	xfs_fileoff_t		orig_offset;
+	xfs_extlen_t		orig_length;
+	int			error;
+	int			stripe_align;
+
+	ASSERT(ap->length);
+	orig_offset = ap->offset;
+	orig_length = ap->length;
+
+	stripe_align = xfs_bmap_compute_alignments(ap, &args);
+
+	/* Trim the allocation back to the maximum an AG can fit. */
+	args.maxlen = min(ap->length, mp->m_ag_max_usable);
+
+	if ((ap->datatype & XFS_ALLOC_USERDATA) &&
+	    xfs_inode_is_filestream(ap->ip))
+		error = xfs_bmap_btalloc_filestreams(ap, &args, stripe_align);
+	else
+		error = xfs_bmap_btalloc_best_length(ap, &args, stripe_align);
+	if (error)
+		return error;
+
 	if (args.fsbno != NULLFSBLOCK) {
 		xfs_bmap_process_allocated_extent(ap, &args, orig_offset,
 			orig_length);
@@ -4256,7 +4222,7 @@ xfs_bmapi_convert_unwritten(
 	return 0;
 }
 
-static inline xfs_extlen_t
+xfs_extlen_t
 xfs_bmapi_minleft(
 	struct xfs_trans	*tp,
 	struct xfs_inode	*ip,
@@ -4264,7 +4230,7 @@ xfs_bmapi_minleft(
 {
 	struct xfs_ifork	*ifp = xfs_ifork_ptr(ip, fork);
 
-	if (tp && tp->t_firstblock != NULLFSBLOCK)
+	if (tp && tp->t_highest_agno != NULLAGNUMBER)
 		return 0;
 	if (ifp->if_format != XFS_DINODE_FMT_BTREE)
 		return 1;
@@ -6151,7 +6117,7 @@ xfs_bmap_finish_one(
 	struct xfs_bmbt_irec		*bmap = &bi->bi_bmap;
 	int				error = 0;
 
-	ASSERT(tp->t_firstblock == NULLFSBLOCK);
+	ASSERT(tp->t_highest_agno == NULLAGNUMBER);
 
 	trace_xfs_bmap_deferred(tp->t_mountp,
 			XFS_FSB_TO_AGNO(tp->t_mountp, bmap->br_startblock),
diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h
index 01c2df35c3e35a..dd08361ca5a699 100644
--- a/fs/xfs/libxfs/xfs_bmap.h
+++ b/fs/xfs/libxfs/xfs_bmap.h
@@ -12,6 +12,7 @@ struct xfs_ifork;
 struct xfs_inode;
 struct xfs_mount;
 struct xfs_trans;
+struct xfs_alloc_arg;
 
 /*
  * Argument structure for xfs_bmap_alloc.
@@ -168,6 +169,8 @@ static inline bool xfs_bmap_is_written_extent(struct xfs_bmbt_irec *irec)
 #define xfs_valid_startblock(ip, startblock) \
 	((startblock) != 0 || XFS_IS_REALTIME_INODE(ip))
 
+int	xfs_bmap_longest_free_extent(struct xfs_perag *pag,
+		struct xfs_trans *tp, xfs_extlen_t *blen);
 void	xfs_trim_extent(struct xfs_bmbt_irec *irec, xfs_fileoff_t bno,
 		xfs_filblks_t len);
 unsigned int xfs_bmap_compute_attr_offset(struct xfs_mount *mp);
@@ -220,6 +223,10 @@ int	xfs_bmap_add_extent_unwritten_real(struct xfs_trans *tp,
 		struct xfs_inode *ip, int whichfork,
 		struct xfs_iext_cursor *icur, struct xfs_btree_cur **curp,
 		struct xfs_bmbt_irec *new, int *logflagsp);
+xfs_extlen_t xfs_bmapi_minleft(struct xfs_trans *tp, struct xfs_inode *ip,
+		int fork);
+int	xfs_bmap_btalloc_low_space(struct xfs_bmalloca *ap,
+		struct xfs_alloc_arg *args);
 
 enum xfs_bmap_intent_type {
 	XFS_BMAP_MAP = 1,
diff --git a/fs/xfs/libxfs/xfs_bmap_btree.c b/fs/xfs/libxfs/xfs_bmap_btree.c
index cfa052d40105dc..b8ad95050c9bd1 100644
--- a/fs/xfs/libxfs/xfs_bmap_btree.c
+++ b/fs/xfs/libxfs/xfs_bmap_btree.c
@@ -21,6 +21,7 @@
 #include "xfs_quota.h"
 #include "xfs_trace.h"
 #include "xfs_rmap.h"
+#include "xfs_ag.h"
 
 static struct kmem_cache	*xfs_bmbt_cur_cache;
 
@@ -184,11 +185,11 @@ xfs_bmbt_update_cursor(
 	struct xfs_btree_cur	*src,
 	struct xfs_btree_cur	*dst)
 {
-	ASSERT((dst->bc_tp->t_firstblock != NULLFSBLOCK) ||
+	ASSERT((dst->bc_tp->t_highest_agno != NULLAGNUMBER) ||
 	       (dst->bc_ino.ip->i_diflags & XFS_DIFLAG_REALTIME));
 
 	dst->bc_ino.allocated += src->bc_ino.allocated;
-	dst->bc_tp->t_firstblock = src->bc_tp->t_firstblock;
+	dst->bc_tp->t_highest_agno = src->bc_tp->t_highest_agno;
 
 	src->bc_ino.allocated = 0;
 }
@@ -200,46 +201,32 @@ xfs_bmbt_alloc_block(
 	union xfs_btree_ptr		*new,
 	int				*stat)
 {
-	xfs_alloc_arg_t		args;		/* block allocation args */
-	int			error;		/* error return value */
+	struct xfs_alloc_arg	args;
+	int			error;
 
 	memset(&args, 0, sizeof(args));
 	args.tp = cur->bc_tp;
 	args.mp = cur->bc_mp;
-	args.fsbno = cur->bc_tp->t_firstblock;
 	xfs_rmap_ino_bmbt_owner(&args.oinfo, cur->bc_ino.ip->i_ino,
 			cur->bc_ino.whichfork);
-
-	if (args.fsbno == NULLFSBLOCK) {
-		args.fsbno = be64_to_cpu(start->l);
-		args.type = XFS_ALLOCTYPE_START_BNO;
-		/*
-		 * Make sure there is sufficient room left in the AG to
-		 * complete a full tree split for an extent insert.  If
-		 * we are converting the middle part of an extent then
-		 * we may need space for two tree splits.
-		 *
-		 * We are relying on the caller to make the correct block
-		 * reservation for this operation to succeed.  If the
-		 * reservation amount is insufficient then we may fail a
-		 * block allocation here and corrupt the filesystem.
-		 */
-		args.minleft = args.tp->t_blk_res;
-	} else if (cur->bc_tp->t_flags & XFS_TRANS_LOWMODE) {
-		args.type = XFS_ALLOCTYPE_START_BNO;
-	} else {
-		args.type = XFS_ALLOCTYPE_NEAR_BNO;
-	}
-
 	args.minlen = args.maxlen = args.prod = 1;
 	args.wasdel = cur->bc_ino.flags & XFS_BTCUR_BMBT_WASDEL;
-	if (!args.wasdel && args.tp->t_blk_res == 0) {
-		error = -ENOSPC;
-		goto error0;
-	}
-	error = xfs_alloc_vextent(&args);
+	if (!args.wasdel && args.tp->t_blk_res == 0)
+		return -ENOSPC;
+
+	/*
+	 * If we are coming here from something like unwritten extent
+	 * conversion, there has been no data extent allocation already done, so
+	 * we have to ensure that we attempt to locate the entire set of bmbt
+	 * allocations in the same AG, as xfs_bmapi_write() would have reserved.
+	 */
+	if (cur->bc_tp->t_highest_agno == NULLAGNUMBER)
+		args.minleft = xfs_bmapi_minleft(cur->bc_tp, cur->bc_ino.ip,
+					cur->bc_ino.whichfork);
+
+	error = xfs_alloc_vextent_start_ag(&args, be64_to_cpu(start->l));
 	if (error)
-		goto error0;
+		return error;
 
 	if (args.fsbno == NULLFSBLOCK && args.minleft) {
 		/*
@@ -247,11 +234,10 @@ xfs_bmbt_alloc_block(
 		 * a full btree split.  Try again and if
 		 * successful activate the lowspace algorithm.
 		 */
-		args.fsbno = 0;
-		args.type = XFS_ALLOCTYPE_FIRST_AG;
-		error = xfs_alloc_vextent(&args);
+		args.minleft = 0;
+		error = xfs_alloc_vextent_start_ag(&args, 0);
 		if (error)
-			goto error0;
+			return error;
 		cur->bc_tp->t_flags |= XFS_TRANS_LOWMODE;
 	}
 	if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
@@ -260,7 +246,6 @@ xfs_bmbt_alloc_block(
 	}
 
 	ASSERT(args.len == 1);
-	cur->bc_tp->t_firstblock = args.fsbno;
 	cur->bc_ino.allocated++;
 	cur->bc_ino.ip->i_nblocks++;
 	xfs_trans_log_inode(args.tp, cur->bc_ino.ip, XFS_ILOG_CORE);
@@ -271,9 +256,6 @@ xfs_bmbt_alloc_block(
 
 	*stat = 1;
 	return 0;
-
- error0:
-	return error;
 }
 
 STATIC int
diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index da8c769887fddc..c4649cc624e1bc 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -2943,7 +2943,7 @@ xfs_btree_split(
 	DECLARE_COMPLETION_ONSTACK(done);
 
 	if (cur->bc_btnum != XFS_BTNUM_BMAP ||
-	    cur->bc_tp->t_firstblock == NULLFSBLOCK)
+	    cur->bc_tp->t_highest_agno == NULLAGNUMBER)
 		return __xfs_btree_split(cur, level, ptrp, key, curp, stat);
 
 	args.cur = cur;
diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
index 5118dedf9267b2..7ee292aecbeb00 100644
--- a/fs/xfs/libxfs/xfs_ialloc.c
+++ b/fs/xfs/libxfs/xfs_ialloc.c
@@ -169,10 +169,9 @@ xfs_inobt_insert_rec(
  */
 STATIC int
 xfs_inobt_insert(
-	struct xfs_mount	*mp,
+	struct xfs_perag	*pag,
 	struct xfs_trans	*tp,
 	struct xfs_buf		*agbp,
-	struct xfs_perag	*pag,
 	xfs_agino_t		newino,
 	xfs_agino_t		newlen,
 	xfs_btnum_t		btnum)
@@ -182,7 +181,7 @@ xfs_inobt_insert(
 	int			i;
 	int			error;
 
-	cur = xfs_inobt_init_cursor(mp, tp, agbp, pag, btnum);
+	cur = xfs_inobt_init_cursor(pag, tp, agbp, btnum);
 
 	for (thisino = newino;
 	     thisino < newino + newlen;
@@ -514,20 +513,20 @@ __xfs_inobt_rec_merge(
  */
 STATIC int
 xfs_inobt_insert_sprec(
-	struct xfs_mount		*mp,
+	struct xfs_perag		*pag,
 	struct xfs_trans		*tp,
 	struct xfs_buf			*agbp,
-	struct xfs_perag		*pag,
 	int				btnum,
 	struct xfs_inobt_rec_incore	*nrec,	/* in/out: new/merged rec. */
 	bool				merge)	/* merge or replace */
 {
+	struct xfs_mount		*mp = pag->pag_mount;
 	struct xfs_btree_cur		*cur;
 	int				error;
 	int				i;
 	struct xfs_inobt_rec_incore	rec;
 
-	cur = xfs_inobt_init_cursor(mp, tp, agbp, pag, btnum);
+	cur = xfs_inobt_init_cursor(pag, tp, agbp, 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);
@@ -609,9 +608,9 @@ error:
  */
 STATIC int
 xfs_ialloc_ag_alloc(
+	struct xfs_perag	*pag,
 	struct xfs_trans	*tp,
-	struct xfs_buf		*agbp,
-	struct xfs_perag	*pag)
+	struct xfs_buf		*agbp)
 {
 	struct xfs_agi		*agi;
 	struct xfs_alloc_arg	args;
@@ -631,6 +630,7 @@ xfs_ialloc_ag_alloc(
 	args.mp = tp->t_mountp;
 	args.fsbno = NULLFSBLOCK;
 	args.oinfo = XFS_RMAP_OINFO_INODES;
+	args.pag = pag;
 
 #ifdef DEBUG
 	/* randomly do sparse inode allocations */
@@ -662,8 +662,6 @@ xfs_ialloc_ag_alloc(
 		goto sparse_alloc;
 	if (likely(newino != NULLAGINO &&
 		  (args.agbno < be32_to_cpu(agi->agi_length)))) {
-		args.fsbno = XFS_AGB_TO_FSB(args.mp, pag->pag_agno, args.agbno);
-		args.type = XFS_ALLOCTYPE_THIS_BNO;
 		args.prod = 1;
 
 		/*
@@ -684,7 +682,10 @@ xfs_ialloc_ag_alloc(
 
 		/* Allow space for the inode btree to split. */
 		args.minleft = igeo->inobt_maxlevels;
-		if ((error = xfs_alloc_vextent(&args)))
+		error = xfs_alloc_vextent_exact_bno(&args,
+				XFS_AGB_TO_FSB(args.mp, pag->pag_agno,
+						args.agbno));
+		if (error)
 			return error;
 
 		/*
@@ -717,22 +718,17 @@ xfs_ialloc_ag_alloc(
 		} else
 			args.alignment = igeo->cluster_align;
 		/*
-		 * Need to figure out where to allocate the inode blocks.
-		 * Ideally they should be spaced out through the a.g.
-		 * For now, just allocate blocks up front.
-		 */
-		args.agbno = be32_to_cpu(agi->agi_root);
-		args.fsbno = XFS_AGB_TO_FSB(args.mp, pag->pag_agno, args.agbno);
-		/*
 		 * Allocate a fixed-size extent of inodes.
 		 */
-		args.type = XFS_ALLOCTYPE_NEAR_BNO;
 		args.prod = 1;
 		/*
 		 * Allow space for the inode btree to split.
 		 */
 		args.minleft = igeo->inobt_maxlevels;
-		if ((error = xfs_alloc_vextent(&args)))
+		error = xfs_alloc_vextent_near_bno(&args,
+				XFS_AGB_TO_FSB(args.mp, pag->pag_agno,
+						be32_to_cpu(agi->agi_root)));
+		if (error)
 			return error;
 	}
 
@@ -741,11 +737,11 @@ xfs_ialloc_ag_alloc(
 	 * alignment.
 	 */
 	if (isaligned && args.fsbno == NULLFSBLOCK) {
-		args.type = XFS_ALLOCTYPE_NEAR_BNO;
-		args.agbno = be32_to_cpu(agi->agi_root);
-		args.fsbno = XFS_AGB_TO_FSB(args.mp, pag->pag_agno, args.agbno);
 		args.alignment = igeo->cluster_align;
-		if ((error = xfs_alloc_vextent(&args)))
+		error = xfs_alloc_vextent_near_bno(&args,
+				XFS_AGB_TO_FSB(args.mp, pag->pag_agno,
+						be32_to_cpu(agi->agi_root)));
+		if (error)
 			return error;
 	}
 
@@ -757,9 +753,6 @@ xfs_ialloc_ag_alloc(
 	    igeo->ialloc_min_blks < igeo->ialloc_blks &&
 	    args.fsbno == NULLFSBLOCK) {
 sparse_alloc:
-		args.type = XFS_ALLOCTYPE_NEAR_BNO;
-		args.agbno = be32_to_cpu(agi->agi_root);
-		args.fsbno = XFS_AGB_TO_FSB(args.mp, pag->pag_agno, args.agbno);
 		args.alignment = args.mp->m_sb.sb_spino_align;
 		args.prod = 1;
 
@@ -781,7 +774,9 @@ sparse_alloc:
 					    args.mp->m_sb.sb_inoalignmt) -
 				 igeo->ialloc_blks;
 
-		error = xfs_alloc_vextent(&args);
+		error = xfs_alloc_vextent_near_bno(&args,
+				XFS_AGB_TO_FSB(args.mp, pag->pag_agno,
+						be32_to_cpu(agi->agi_root)));
 		if (error)
 			return error;
 
@@ -831,7 +826,7 @@ sparse_alloc:
 		 * if necessary. If a merge does occur, rec is updated to the
 		 * merged record.
 		 */
-		error = xfs_inobt_insert_sprec(args.mp, tp, agbp, pag,
+		error = xfs_inobt_insert_sprec(pag, tp, agbp,
 				XFS_BTNUM_INO, &rec, true);
 		if (error == -EFSCORRUPTED) {
 			xfs_alert(args.mp,
@@ -856,20 +851,20 @@ sparse_alloc:
 		 * existing record with this one.
 		 */
 		if (xfs_has_finobt(args.mp)) {
-			error = xfs_inobt_insert_sprec(args.mp, tp, agbp, pag,
+			error = xfs_inobt_insert_sprec(pag, tp, agbp,
 				       XFS_BTNUM_FINO, &rec, false);
 			if (error)
 				return error;
 		}
 	} else {
 		/* full chunk - insert new records to both btrees */
-		error = xfs_inobt_insert(args.mp, tp, agbp, pag, newino, newlen,
+		error = xfs_inobt_insert(pag, tp, agbp, newino, newlen,
 					 XFS_BTNUM_INO);
 		if (error)
 			return error;
 
 		if (xfs_has_finobt(args.mp)) {
-			error = xfs_inobt_insert(args.mp, tp, agbp, pag, newino,
+			error = xfs_inobt_insert(pag, tp, agbp, newino,
 						 newlen, XFS_BTNUM_FINO);
 			if (error)
 				return error;
@@ -981,9 +976,9 @@ xfs_inobt_first_free_inode(
  */
 STATIC int
 xfs_dialloc_ag_inobt(
+	struct xfs_perag	*pag,
 	struct xfs_trans	*tp,
 	struct xfs_buf		*agbp,
-	struct xfs_perag	*pag,
 	xfs_ino_t		parent,
 	xfs_ino_t		*inop)
 {
@@ -999,12 +994,12 @@ xfs_dialloc_ag_inobt(
 	int			i, j;
 	int			searchdistance = 10;
 
-	ASSERT(pag->pagi_init);
-	ASSERT(pag->pagi_inodeok);
+	ASSERT(xfs_perag_initialised_agi(pag));
+	ASSERT(xfs_perag_allows_inodes(pag));
 	ASSERT(pag->pagi_freecount > 0);
 
  restart_pagno:
-	cur = xfs_inobt_init_cursor(mp, tp, agbp, pag, XFS_BTNUM_INO);
+	cur = xfs_inobt_init_cursor(pag, tp, agbp, XFS_BTNUM_INO);
 	/*
 	 * If pagino is 0 (this is the root inode allocation) use newino.
 	 * This must work because we've just allocated some.
@@ -1429,9 +1424,9 @@ xfs_dialloc_ag_update_inobt(
  */
 static int
 xfs_dialloc_ag(
+	struct xfs_perag	*pag,
 	struct xfs_trans	*tp,
 	struct xfs_buf		*agbp,
-	struct xfs_perag	*pag,
 	xfs_ino_t		parent,
 	xfs_ino_t		*inop)
 {
@@ -1448,7 +1443,7 @@ xfs_dialloc_ag(
 	int				i;
 
 	if (!xfs_has_finobt(mp))
-		return xfs_dialloc_ag_inobt(tp, agbp, pag, parent, inop);
+		return xfs_dialloc_ag_inobt(pag, tp, agbp, parent, inop);
 
 	/*
 	 * If pagino is 0 (this is the root inode allocation) use newino.
@@ -1457,7 +1452,7 @@ xfs_dialloc_ag(
 	if (!pagino)
 		pagino = be32_to_cpu(agi->agi_newino);
 
-	cur = xfs_inobt_init_cursor(mp, tp, agbp, pag, XFS_BTNUM_FINO);
+	cur = xfs_inobt_init_cursor(pag, tp, agbp, XFS_BTNUM_FINO);
 
 	error = xfs_check_agi_freecount(cur);
 	if (error)
@@ -1500,7 +1495,7 @@ 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, pag, XFS_BTNUM_INO);
+	icur = xfs_inobt_init_cursor(pag, tp, agbp, XFS_BTNUM_INO);
 
 	error = xfs_check_agi_freecount(icur);
 	if (error)
@@ -1577,25 +1572,10 @@ xfs_dialloc_roll(
 	return error;
 }
 
-static xfs_agnumber_t
-xfs_ialloc_next_ag(
-	xfs_mount_t	*mp)
-{
-	xfs_agnumber_t	agno;
-
-	spin_lock(&mp->m_agirotor_lock);
-	agno = mp->m_agirotor;
-	if (++mp->m_agirotor >= mp->m_maxagi)
-		mp->m_agirotor = 0;
-	spin_unlock(&mp->m_agirotor_lock);
-
-	return agno;
-}
-
 static bool
 xfs_dialloc_good_ag(
-	struct xfs_trans	*tp,
 	struct xfs_perag	*pag,
+	struct xfs_trans	*tp,
 	umode_t			mode,
 	int			flags,
 	bool			ok_alloc)
@@ -1606,10 +1586,12 @@ xfs_dialloc_good_ag(
 	int			needspace;
 	int			error;
 
-	if (!pag->pagi_inodeok)
+	if (!pag)
+		return false;
+	if (!xfs_perag_allows_inodes(pag))
 		return false;
 
-	if (!pag->pagi_init) {
+	if (!xfs_perag_initialised_agi(pag)) {
 		error = xfs_ialloc_read_agi(pag, tp, NULL);
 		if (error)
 			return false;
@@ -1620,7 +1602,7 @@ xfs_dialloc_good_ag(
 	if (!ok_alloc)
 		return false;
 
-	if (!pag->pagf_init) {
+	if (!xfs_perag_initialised_agf(pag)) {
 		error = xfs_alloc_read_agf(pag, tp, flags, NULL);
 		if (error)
 			return false;
@@ -1665,8 +1647,8 @@ xfs_dialloc_good_ag(
 
 static int
 xfs_dialloc_try_ag(
-	struct xfs_trans	**tpp,
 	struct xfs_perag	*pag,
+	struct xfs_trans	**tpp,
 	xfs_ino_t		parent,
 	xfs_ino_t		*new_ino,
 	bool			ok_alloc)
@@ -1689,7 +1671,7 @@ xfs_dialloc_try_ag(
 			goto out_release;
 		}
 
-		error = xfs_ialloc_ag_alloc(*tpp, agbp, pag);
+		error = xfs_ialloc_ag_alloc(pag, *tpp, agbp);
 		if (error < 0)
 			goto out_release;
 
@@ -1705,7 +1687,7 @@ xfs_dialloc_try_ag(
 	}
 
 	/* Allocate an inode in the found AG */
-	error = xfs_dialloc_ag(*tpp, agbp, pag, parent, &ino);
+	error = xfs_dialloc_ag(pag, *tpp, agbp, parent, &ino);
 	if (!error)
 		*new_ino = ino;
 	return error;
@@ -1737,8 +1719,9 @@ xfs_dialloc(
 	struct xfs_perag	*pag;
 	struct xfs_ino_geometry	*igeo = M_IGEO(mp);
 	bool			ok_alloc = true;
+	bool			low_space = false;
 	int			flags;
-	xfs_ino_t		ino;
+	xfs_ino_t		ino = NULLFSINO;
 
 	/*
 	 * Directories, symlinks, and regular files frequently allocate at least
@@ -1746,7 +1729,8 @@ xfs_dialloc(
 	 * an AG has enough space for file creation.
 	 */
 	if (S_ISDIR(mode))
-		start_agno = xfs_ialloc_next_ag(mp);
+		start_agno = (atomic_inc_return(&mp->m_agirotor) - 1) %
+				mp->m_maxagi;
 	else {
 		start_agno = XFS_INO_TO_AGNO(mp, parent);
 		if (start_agno >= mp->m_maxagi)
@@ -1768,41 +1752,55 @@ xfs_dialloc(
 	}
 
 	/*
+	 * If we are near to ENOSPC, we want to prefer allocation from AGs that
+	 * have free inodes in them rather than use up free space allocating new
+	 * inode chunks. Hence we turn off allocation for the first non-blocking
+	 * pass through the AGs if we are near ENOSPC to consume free inodes
+	 * that we can immediately allocate, but then we allow allocation on the
+	 * second pass if we fail to find an AG with free inodes in it.
+	 */
+	if (percpu_counter_read_positive(&mp->m_fdblocks) <
+			mp->m_low_space[XFS_LOWSP_1_PCNT]) {
+		ok_alloc = false;
+		low_space = true;
+	}
+
+	/*
 	 * Loop until we find an allocation group that either has free inodes
 	 * or in which we can allocate some inodes.  Iterate through the
 	 * allocation groups upward, wrapping at the end.
 	 */
-	agno = start_agno;
 	flags = XFS_ALLOC_FLAG_TRYLOCK;
-	for (;;) {
-		pag = xfs_perag_get(mp, agno);
-		if (xfs_dialloc_good_ag(*tpp, pag, mode, flags, ok_alloc)) {
-			error = xfs_dialloc_try_ag(tpp, pag, parent,
+retry:
+	for_each_perag_wrap_at(mp, start_agno, mp->m_maxagi, agno, pag) {
+		if (xfs_dialloc_good_ag(pag, *tpp, mode, flags, ok_alloc)) {
+			error = xfs_dialloc_try_ag(pag, tpp, parent,
 					&ino, ok_alloc);
 			if (error != -EAGAIN)
 				break;
+			error = 0;
 		}
 
 		if (xfs_is_shutdown(mp)) {
 			error = -EFSCORRUPTED;
 			break;
 		}
-		if (++agno == mp->m_maxagi)
-			agno = 0;
-		if (agno == start_agno) {
-			if (!flags) {
-				error = -ENOSPC;
-				break;
-			}
+	}
+	if (pag)
+		xfs_perag_rele(pag);
+	if (error)
+		return error;
+	if (ino == NULLFSINO) {
+		if (flags) {
 			flags = 0;
+			if (low_space)
+				ok_alloc = true;
+			goto retry;
 		}
-		xfs_perag_put(pag);
+		return -ENOSPC;
 	}
-
-	if (!error)
-		*new_ino = ino;
-	xfs_perag_put(pag);
-	return error;
+	*new_ino = ino;
+	return 0;
 }
 
 /*
@@ -1885,14 +1883,14 @@ next:
 
 STATIC int
 xfs_difree_inobt(
-	struct xfs_mount		*mp,
+	struct xfs_perag		*pag,
 	struct xfs_trans		*tp,
 	struct xfs_buf			*agbp,
-	struct xfs_perag		*pag,
 	xfs_agino_t			agino,
 	struct xfs_icluster		*xic,
 	struct xfs_inobt_rec_incore	*orec)
 {
+	struct xfs_mount		*mp = pag->pag_mount;
 	struct xfs_agi			*agi = agbp->b_addr;
 	struct xfs_btree_cur		*cur;
 	struct xfs_inobt_rec_incore	rec;
@@ -1907,7 +1905,7 @@ xfs_difree_inobt(
 	/*
 	 * Initialize the cursor.
 	 */
-	cur = xfs_inobt_init_cursor(mp, tp, agbp, pag, XFS_BTNUM_INO);
+	cur = xfs_inobt_init_cursor(pag, tp, agbp, XFS_BTNUM_INO);
 
 	error = xfs_check_agi_freecount(cur);
 	if (error)
@@ -2019,20 +2017,20 @@ error0:
  */
 STATIC int
 xfs_difree_finobt(
-	struct xfs_mount		*mp,
+	struct xfs_perag		*pag,
 	struct xfs_trans		*tp,
 	struct xfs_buf			*agbp,
-	struct xfs_perag		*pag,
 	xfs_agino_t			agino,
 	struct xfs_inobt_rec_incore	*ibtrec) /* inobt record */
 {
+	struct xfs_mount		*mp = pag->pag_mount;
 	struct xfs_btree_cur		*cur;
 	struct xfs_inobt_rec_incore	rec;
 	int				offset = agino - ibtrec->ir_startino;
 	int				error;
 	int				i;
 
-	cur = xfs_inobt_init_cursor(mp, tp, agbp, pag, XFS_BTNUM_FINO);
+	cur = xfs_inobt_init_cursor(pag, tp, agbp, XFS_BTNUM_FINO);
 
 	error = xfs_inobt_lookup(cur, ibtrec->ir_startino, XFS_LOOKUP_EQ, &i);
 	if (error)
@@ -2179,7 +2177,7 @@ xfs_difree(
 	/*
 	 * Fix up the inode allocation btree.
 	 */
-	error = xfs_difree_inobt(mp, tp, agbp, pag, agino, xic, &rec);
+	error = xfs_difree_inobt(pag, tp, agbp, agino, xic, &rec);
 	if (error)
 		goto error0;
 
@@ -2187,7 +2185,7 @@ xfs_difree(
 	 * Fix up the free inode btree.
 	 */
 	if (xfs_has_finobt(mp)) {
-		error = xfs_difree_finobt(mp, tp, agbp, pag, agino, &rec);
+		error = xfs_difree_finobt(pag, tp, agbp, agino, &rec);
 		if (error)
 			goto error0;
 	}
@@ -2200,15 +2198,15 @@ error0:
 
 STATIC int
 xfs_imap_lookup(
-	struct xfs_mount	*mp,
-	struct xfs_trans	*tp,
 	struct xfs_perag	*pag,
+	struct xfs_trans	*tp,
 	xfs_agino_t		agino,
 	xfs_agblock_t		agbno,
 	xfs_agblock_t		*chunk_agbno,
 	xfs_agblock_t		*offset_agbno,
 	int			flags)
 {
+	struct xfs_mount	*mp = pag->pag_mount;
 	struct xfs_inobt_rec_incore rec;
 	struct xfs_btree_cur	*cur;
 	struct xfs_buf		*agbp;
@@ -2229,7 +2227,7 @@ 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, pag, XFS_BTNUM_INO);
+	cur = xfs_inobt_init_cursor(pag, tp, agbp, XFS_BTNUM_INO);
 	error = xfs_inobt_lookup(cur, agino, XFS_LOOKUP_LE, &i);
 	if (!error) {
 		if (i)
@@ -2263,12 +2261,13 @@ xfs_imap_lookup(
  */
 int
 xfs_imap(
-	struct xfs_mount	 *mp,	/* file system mount structure */
-	struct xfs_trans	 *tp,	/* transaction pointer */
+	struct xfs_perag	*pag,
+	struct xfs_trans	*tp,
 	xfs_ino_t		ino,	/* inode to locate */
 	struct xfs_imap		*imap,	/* location map structure */
 	uint			flags)	/* flags for inode btree lookup */
 {
+	struct xfs_mount	*mp = pag->pag_mount;
 	xfs_agblock_t		agbno;	/* block number of inode in the alloc group */
 	xfs_agino_t		agino;	/* inode number within alloc group */
 	xfs_agblock_t		chunk_agbno;	/* first block in inode chunk */
@@ -2276,17 +2275,15 @@ xfs_imap(
 	int			error;	/* error code */
 	int			offset;	/* index of inode in its buffer */
 	xfs_agblock_t		offset_agbno;	/* blks from chunk start to inode */
-	struct xfs_perag	*pag;
 
 	ASSERT(ino != NULLFSINO);
 
 	/*
 	 * Split up the inode number into its parts.
 	 */
-	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ino));
 	agino = XFS_INO_TO_AGINO(mp, ino);
 	agbno = XFS_AGINO_TO_AGBNO(mp, agino);
-	if (!pag || agbno >= mp->m_sb.sb_agblocks ||
+	if (agbno >= mp->m_sb.sb_agblocks ||
 	    ino != XFS_AGINO_TO_INO(mp, pag->pag_agno, agino)) {
 		error = -EINVAL;
 #ifdef DEBUG
@@ -2295,20 +2292,14 @@ xfs_imap(
 		 * as they can be invalid without implying corruption.
 		 */
 		if (flags & XFS_IGET_UNTRUSTED)
-			goto out_drop;
-		if (!pag) {
-			xfs_alert(mp,
-				"%s: agno (%d) >= mp->m_sb.sb_agcount (%d)",
-				__func__, XFS_INO_TO_AGNO(mp, ino),
-				mp->m_sb.sb_agcount);
-		}
+			return error;
 		if (agbno >= mp->m_sb.sb_agblocks) {
 			xfs_alert(mp,
 		"%s: agbno (0x%llx) >= mp->m_sb.sb_agblocks (0x%lx)",
 				__func__, (unsigned long long)agbno,
 				(unsigned long)mp->m_sb.sb_agblocks);
 		}
-		if (pag && ino != XFS_AGINO_TO_INO(mp, pag->pag_agno, agino)) {
+		if (ino != XFS_AGINO_TO_INO(mp, pag->pag_agno, agino)) {
 			xfs_alert(mp,
 		"%s: ino (0x%llx) != XFS_AGINO_TO_INO() (0x%llx)",
 				__func__, ino,
@@ -2316,7 +2307,7 @@ xfs_imap(
 		}
 		xfs_stack_trace();
 #endif /* DEBUG */
-		goto out_drop;
+		return error;
 	}
 
 	/*
@@ -2327,10 +2318,10 @@ xfs_imap(
 	 * in all cases where an untrusted inode number is passed.
 	 */
 	if (flags & XFS_IGET_UNTRUSTED) {
-		error = xfs_imap_lookup(mp, tp, pag, agino, agbno,
+		error = xfs_imap_lookup(pag, tp, agino, agbno,
 					&chunk_agbno, &offset_agbno, flags);
 		if (error)
-			goto out_drop;
+			return error;
 		goto out_map;
 	}
 
@@ -2346,8 +2337,7 @@ xfs_imap(
 		imap->im_len = XFS_FSB_TO_BB(mp, 1);
 		imap->im_boffset = (unsigned short)(offset <<
 							mp->m_sb.sb_inodelog);
-		error = 0;
-		goto out_drop;
+		return 0;
 	}
 
 	/*
@@ -2359,10 +2349,10 @@ xfs_imap(
 		offset_agbno = agbno & M_IGEO(mp)->inoalign_mask;
 		chunk_agbno = agbno - offset_agbno;
 	} else {
-		error = xfs_imap_lookup(mp, tp, pag, agino, agbno,
+		error = xfs_imap_lookup(pag, tp, agino, agbno,
 					&chunk_agbno, &offset_agbno, flags);
 		if (error)
-			goto out_drop;
+			return error;
 	}
 
 out_map:
@@ -2390,14 +2380,9 @@ out_map:
 			__func__, (unsigned long long) imap->im_blkno,
 			(unsigned long long) imap->im_len,
 			XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks));
-		error = -EINVAL;
-		goto out_drop;
+		return -EINVAL;
 	}
-	error = 0;
-out_drop:
-	if (pag)
-		xfs_perag_put(pag);
-	return error;
+	return 0;
 }
 
 /*
@@ -2613,10 +2598,10 @@ xfs_ialloc_read_agi(
 		return error;
 
 	agi = agibp->b_addr;
-	if (!pag->pagi_init) {
+	if (!xfs_perag_initialised_agi(pag)) {
 		pag->pagi_freecount = be32_to_cpu(agi->agi_freecount);
 		pag->pagi_count = be32_to_cpu(agi->agi_count);
-		pag->pagi_init = 1;
+		set_bit(XFS_AGSTATE_AGI_INIT, &pag->pag_opstate);
 	}
 
 	/*
@@ -2924,26 +2909,24 @@ xfs_ialloc_calc_rootino(
  */
 int
 xfs_ialloc_check_shrink(
+	struct xfs_perag	*pag,
 	struct xfs_trans	*tp,
-	xfs_agnumber_t		agno,
 	struct xfs_buf		*agibp,
 	xfs_agblock_t		new_length)
 {
 	struct xfs_inobt_rec_incore rec;
 	struct xfs_btree_cur	*cur;
-	struct xfs_mount	*mp = tp->t_mountp;
-	struct xfs_perag	*pag;
-	xfs_agino_t		agino = XFS_AGB_TO_AGINO(mp, new_length);
+	xfs_agino_t		agino;
 	int			has;
 	int			error;
 
-	if (!xfs_has_sparseinodes(mp))
+	if (!xfs_has_sparseinodes(pag->pag_mount))
 		return 0;
 
-	pag = xfs_perag_get(mp, agno);
-	cur = xfs_inobt_init_cursor(mp, tp, agibp, pag, XFS_BTNUM_INO);
+	cur = xfs_inobt_init_cursor(pag, tp, agibp, XFS_BTNUM_INO);
 
 	/* Look up the inobt record that would correspond to the new EOFS. */
+	agino = XFS_AGB_TO_AGINO(pag->pag_mount, new_length);
 	error = xfs_inobt_lookup(cur, agino, XFS_LOOKUP_LE, &has);
 	if (error || !has)
 		goto out;
@@ -2964,6 +2947,5 @@ xfs_ialloc_check_shrink(
 	}
 out:
 	xfs_btree_del_cursor(cur, error);
-	xfs_perag_put(pag);
 	return error;
 }
diff --git a/fs/xfs/libxfs/xfs_ialloc.h b/fs/xfs/libxfs/xfs_ialloc.h
index 9bbbca6ac4edf9..ab8c30b4ec22cd 100644
--- a/fs/xfs/libxfs/xfs_ialloc.h
+++ b/fs/xfs/libxfs/xfs_ialloc.h
@@ -12,6 +12,7 @@ struct xfs_imap;
 struct xfs_mount;
 struct xfs_trans;
 struct xfs_btree_cur;
+struct xfs_perag;
 
 /* Move inodes in clusters of this size */
 #define	XFS_INODE_BIG_CLUSTER_SIZE	8192
@@ -47,7 +48,7 @@ int xfs_difree(struct xfs_trans *tp, struct xfs_perag *pag,
  */
 int
 xfs_imap(
-	struct xfs_mount *mp,		/* file system mount structure */
+	struct xfs_perag *pag,
 	struct xfs_trans *tp,		/* transaction pointer */
 	xfs_ino_t	ino,		/* inode to locate */
 	struct xfs_imap	*imap,		/* location map structure */
@@ -106,7 +107,7 @@ int xfs_ialloc_cluster_alignment(struct xfs_mount *mp);
 void xfs_ialloc_setup_geometry(struct xfs_mount *mp);
 xfs_ino_t xfs_ialloc_calc_rootino(struct xfs_mount *mp, int sunit);
 
-int xfs_ialloc_check_shrink(struct xfs_trans *tp, xfs_agnumber_t agno,
+int xfs_ialloc_check_shrink(struct xfs_perag *pag, struct xfs_trans *tp,
 		struct xfs_buf *agibp, xfs_agblock_t new_length);
 
 #endif	/* __XFS_IALLOC_H__ */
diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c
index 8c83e265770c10..9b28211d5a4c56 100644
--- a/fs/xfs/libxfs/xfs_ialloc_btree.c
+++ b/fs/xfs/libxfs/xfs_ialloc_btree.c
@@ -36,8 +36,8 @@ STATIC struct xfs_btree_cur *
 xfs_inobt_dup_cursor(
 	struct xfs_btree_cur	*cur)
 {
-	return xfs_inobt_init_cursor(cur->bc_mp, cur->bc_tp,
-			cur->bc_ag.agbp, cur->bc_ag.pag, cur->bc_btnum);
+	return xfs_inobt_init_cursor(cur->bc_ag.pag, cur->bc_tp,
+			cur->bc_ag.agbp, cur->bc_btnum);
 }
 
 STATIC void
@@ -103,15 +103,15 @@ __xfs_inobt_alloc_block(
 	memset(&args, 0, sizeof(args));
 	args.tp = cur->bc_tp;
 	args.mp = cur->bc_mp;
+	args.pag = cur->bc_ag.pag;
 	args.oinfo = XFS_RMAP_OINFO_INOBT;
-	args.fsbno = XFS_AGB_TO_FSB(args.mp, cur->bc_ag.pag->pag_agno, sbno);
 	args.minlen = 1;
 	args.maxlen = 1;
 	args.prod = 1;
-	args.type = XFS_ALLOCTYPE_NEAR_BNO;
 	args.resv = resv;
 
-	error = xfs_alloc_vextent(&args);
+	error = xfs_alloc_vextent_near_bno(&args,
+			XFS_AGB_TO_FSB(args.mp, args.pag->pag_agno, sbno));
 	if (error)
 		return error;
 
@@ -291,8 +291,8 @@ xfs_inobt_verify(
 	 * Similarly, during log recovery we will have a perag structure
 	 * attached, but the agi information will not yet have been initialised
 	 * from the on disk AGI. We don't currently use any of this information,
-	 * but beware of the landmine (i.e. need to check pag->pagi_init) if we
-	 * ever do.
+	 * but beware of the landmine (i.e. need to check
+	 * xfs_perag_initialised_agi(pag)) if we ever do.
 	 */
 	if (xfs_has_crc(mp)) {
 		fa = xfs_btree_sblock_v5hdr_verify(bp);
@@ -427,11 +427,11 @@ static const struct xfs_btree_ops xfs_finobt_ops = {
  */
 static struct xfs_btree_cur *
 xfs_inobt_init_common(
-	struct xfs_mount	*mp,		/* file system mount point */
-	struct xfs_trans	*tp,		/* transaction pointer */
 	struct xfs_perag	*pag,
+	struct xfs_trans	*tp,		/* transaction pointer */
 	xfs_btnum_t		btnum)		/* ialloc or free ino btree */
 {
+	struct xfs_mount	*mp = pag->pag_mount;
 	struct xfs_btree_cur	*cur;
 
 	cur = xfs_btree_alloc_cursor(mp, tp, btnum,
@@ -456,16 +456,15 @@ xfs_inobt_init_common(
 /* Create an inode btree cursor. */
 struct xfs_btree_cur *
 xfs_inobt_init_cursor(
-	struct xfs_mount	*mp,
+	struct xfs_perag	*pag,
 	struct xfs_trans	*tp,
 	struct xfs_buf		*agbp,
-	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, pag, btnum);
+	cur = xfs_inobt_init_common(pag, tp, btnum);
 	if (btnum == XFS_BTNUM_INO)
 		cur->bc_nlevels = be32_to_cpu(agi->agi_level);
 	else
@@ -477,14 +476,13 @@ xfs_inobt_init_cursor(
 /* Create an inode btree cursor with a fake root for staging. */
 struct xfs_btree_cur *
 xfs_inobt_stage_cursor(
-	struct xfs_mount	*mp,
-	struct xbtree_afakeroot	*afake,
 	struct xfs_perag	*pag,
+	struct xbtree_afakeroot	*afake,
 	xfs_btnum_t		btnum)
 {
 	struct xfs_btree_cur	*cur;
 
-	cur = xfs_inobt_init_common(mp, NULL, pag, btnum);
+	cur = xfs_inobt_init_common(pag, NULL, btnum);
 	xfs_btree_stage_afakeroot(cur, afake);
 	return cur;
 }
@@ -708,9 +706,8 @@ xfs_inobt_max_size(
 /* Read AGI and create inobt cursor. */
 int
 xfs_inobt_cur(
-	struct xfs_mount	*mp,
-	struct xfs_trans	*tp,
 	struct xfs_perag	*pag,
+	struct xfs_trans	*tp,
 	xfs_btnum_t		which,
 	struct xfs_btree_cur	**curpp,
 	struct xfs_buf		**agi_bpp)
@@ -725,16 +722,15 @@ xfs_inobt_cur(
 	if (error)
 		return error;
 
-	cur = xfs_inobt_init_cursor(mp, tp, *agi_bpp, pag, which);
+	cur = xfs_inobt_init_cursor(pag, tp, *agi_bpp, which);
 	*curpp = cur;
 	return 0;
 }
 
 static int
 xfs_inobt_count_blocks(
-	struct xfs_mount	*mp,
-	struct xfs_trans	*tp,
 	struct xfs_perag	*pag,
+	struct xfs_trans	*tp,
 	xfs_btnum_t		btnum,
 	xfs_extlen_t		*tree_blocks)
 {
@@ -742,7 +738,7 @@ xfs_inobt_count_blocks(
 	struct xfs_btree_cur	*cur = NULL;
 	int			error;
 
-	error = xfs_inobt_cur(mp, tp, pag, btnum, &cur, &agbp);
+	error = xfs_inobt_cur(pag, tp, btnum, &cur, &agbp);
 	if (error)
 		return error;
 
@@ -779,22 +775,21 @@ xfs_finobt_read_blocks(
  */
 int
 xfs_finobt_calc_reserves(
-	struct xfs_mount	*mp,
-	struct xfs_trans	*tp,
 	struct xfs_perag	*pag,
+	struct xfs_trans	*tp,
 	xfs_extlen_t		*ask,
 	xfs_extlen_t		*used)
 {
 	xfs_extlen_t		tree_len = 0;
 	int			error;
 
-	if (!xfs_has_finobt(mp))
+	if (!xfs_has_finobt(pag->pag_mount))
 		return 0;
 
-	if (xfs_has_inobtcounts(mp))
+	if (xfs_has_inobtcounts(pag->pag_mount))
 		error = xfs_finobt_read_blocks(pag, tp, &tree_len);
 	else
-		error = xfs_inobt_count_blocks(mp, tp, pag, XFS_BTNUM_FINO,
+		error = xfs_inobt_count_blocks(pag, tp, XFS_BTNUM_FINO,
 				&tree_len);
 	if (error)
 		return error;
diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.h b/fs/xfs/libxfs/xfs_ialloc_btree.h
index 26451cb76b98bb..e859a6e0523096 100644
--- a/fs/xfs/libxfs/xfs_ialloc_btree.h
+++ b/fs/xfs/libxfs/xfs_ialloc_btree.h
@@ -46,12 +46,10 @@ struct xfs_perag;
 		 (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 *mp,
-		struct xfs_trans *tp, struct xfs_buf *agbp,
-		struct xfs_perag *pag, xfs_btnum_t btnum);
-struct xfs_btree_cur *xfs_inobt_stage_cursor(struct xfs_mount *mp,
-		struct xbtree_afakeroot *afake, struct xfs_perag *pag,
-		xfs_btnum_t btnum);
+extern struct xfs_btree_cur *xfs_inobt_init_cursor(struct xfs_perag *pag,
+		struct xfs_trans *tp, struct xfs_buf *agbp, xfs_btnum_t btnum);
+struct xfs_btree_cur *xfs_inobt_stage_cursor(struct xfs_perag *pag,
+		struct xbtree_afakeroot *afake, xfs_btnum_t btnum);
 extern int xfs_inobt_maxrecs(struct xfs_mount *, int, int);
 
 /* ir_holemask to inode allocation bitmap conversion */
@@ -64,13 +62,13 @@ int xfs_inobt_rec_check_count(struct xfs_mount *,
 #define xfs_inobt_rec_check_count(mp, rec)	0
 #endif	/* DEBUG */
 
-int xfs_finobt_calc_reserves(struct xfs_mount *mp, struct xfs_trans *tp,
-		struct xfs_perag *pag, xfs_extlen_t *ask, xfs_extlen_t *used);
+int xfs_finobt_calc_reserves(struct xfs_perag *perag, struct xfs_trans *tp,
+		xfs_extlen_t *ask, xfs_extlen_t *used);
 extern xfs_extlen_t xfs_iallocbt_calc_size(struct xfs_mount *mp,
 		unsigned long long len);
-int xfs_inobt_cur(struct xfs_mount *mp, struct xfs_trans *tp,
-		struct xfs_perag *pag, xfs_btnum_t btnum,
-		struct xfs_btree_cur **curpp, struct xfs_buf **agi_bpp);
+int xfs_inobt_cur(struct xfs_perag *pag, struct xfs_trans *tp,
+		xfs_btnum_t btnum, struct xfs_btree_cur **curpp,
+		struct xfs_buf **agi_bpp);
 
 void xfs_inobt_commit_staged_btree(struct xfs_btree_cur *cur,
 		struct xfs_trans *tp, struct xfs_buf *agbp);
diff --git a/fs/xfs/libxfs/xfs_refcount_btree.c b/fs/xfs/libxfs/xfs_refcount_btree.c
index e1f7898666831f..f3b860970b2608 100644
--- a/fs/xfs/libxfs/xfs_refcount_btree.c
+++ b/fs/xfs/libxfs/xfs_refcount_btree.c
@@ -67,14 +67,14 @@ xfs_refcountbt_alloc_block(
 	memset(&args, 0, sizeof(args));
 	args.tp = cur->bc_tp;
 	args.mp = cur->bc_mp;
-	args.type = XFS_ALLOCTYPE_NEAR_BNO;
-	args.fsbno = XFS_AGB_TO_FSB(cur->bc_mp, cur->bc_ag.pag->pag_agno,
-			xfs_refc_block(args.mp));
+	args.pag = cur->bc_ag.pag;
 	args.oinfo = XFS_RMAP_OINFO_REFC;
 	args.minlen = args.maxlen = args.prod = 1;
 	args.resv = XFS_AG_RESV_METADATA;
 
-	error = xfs_alloc_vextent(&args);
+	error = xfs_alloc_vextent_near_bno(&args,
+			XFS_AGB_TO_FSB(args.mp, args.pag->pag_agno,
+					xfs_refc_block(args.mp)));
 	if (error)
 		goto out_error;
 	trace_xfs_refcountbt_alloc_block(cur->bc_mp, cur->bc_ag.pag->pag_agno,
@@ -227,7 +227,7 @@ xfs_refcountbt_verify(
 		return fa;
 
 	level = be16_to_cpu(block->bb_level);
-	if (pag && pag->pagf_init) {
+	if (pag && xfs_perag_initialised_agf(pag)) {
 		if (level >= pag->pagf_refcount_level)
 			return __this_address;
 	} else if (level >= mp->m_refc_maxlevels)
diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c
index 7f83f62e51e0bf..d3285684bb5eb3 100644
--- a/fs/xfs/libxfs/xfs_rmap_btree.c
+++ b/fs/xfs/libxfs/xfs_rmap_btree.c
@@ -313,7 +313,7 @@ xfs_rmapbt_verify(
 		return fa;
 
 	level = be16_to_cpu(block->bb_level);
-	if (pag && pag->pagf_init) {
+	if (pag && xfs_perag_initialised_agf(pag)) {
 		if (level >= pag->pagf_levels[XFS_BTNUM_RMAPi])
 			return __this_address;
 	} else if (level >= mp->m_rmap_maxlevels)
diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
index 1eeecf2eb2a772..99cc03a298e21c 100644
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -909,7 +909,8 @@ xfs_sb_mount_common(
 	struct xfs_mount	*mp,
 	struct xfs_sb		*sbp)
 {
-	mp->m_agfrotor = mp->m_agirotor = 0;
+	mp->m_agfrotor = 0;
+	atomic_set(&mp->m_agirotor, 0);
 	mp->m_maxagi = mp->m_sb.sb_agcount;
 	mp->m_blkbit_log = sbp->sb_blocklog + XFS_NBBYLOG;
 	mp->m_blkbb_log = sbp->sb_blocklog - BBSHIFT;
diff --git a/fs/xfs/scrub/agheader_repair.c b/fs/xfs/scrub/agheader_repair.c
index d75d82151eeba3..c37e6d72760b9d 100644
--- a/fs/xfs/scrub/agheader_repair.c
+++ b/fs/xfs/scrub/agheader_repair.c
@@ -191,14 +191,15 @@ xrep_agf_init_header(
 	struct xfs_agf		*old_agf)
 {
 	struct xfs_mount	*mp = sc->mp;
+	struct xfs_perag	*pag = sc->sa.pag;
 	struct xfs_agf		*agf = agf_bp->b_addr;
 
 	memcpy(old_agf, agf, sizeof(*old_agf));
 	memset(agf, 0, BBTOB(agf_bp->b_length));
 	agf->agf_magicnum = cpu_to_be32(XFS_AGF_MAGIC);
 	agf->agf_versionnum = cpu_to_be32(XFS_AGF_VERSION);
-	agf->agf_seqno = cpu_to_be32(sc->sa.pag->pag_agno);
-	agf->agf_length = cpu_to_be32(sc->sa.pag->block_count);
+	agf->agf_seqno = cpu_to_be32(pag->pag_agno);
+	agf->agf_length = cpu_to_be32(pag->block_count);
 	agf->agf_flfirst = old_agf->agf_flfirst;
 	agf->agf_fllast = old_agf->agf_fllast;
 	agf->agf_flcount = old_agf->agf_flcount;
@@ -206,8 +207,8 @@ xrep_agf_init_header(
 		uuid_copy(&agf->agf_uuid, &mp->m_sb.sb_meta_uuid);
 
 	/* Mark the incore AGF data stale until we're done fixing things. */
-	ASSERT(sc->sa.pag->pagf_init);
-	sc->sa.pag->pagf_init = 0;
+	ASSERT(xfs_perag_initialised_agf(pag));
+	clear_bit(XFS_AGSTATE_AGF_INIT, &pag->pag_opstate);
 }
 
 /* Set btree root information in an AGF. */
@@ -333,7 +334,7 @@ xrep_agf_commit_new(
 	pag->pagf_levels[XFS_BTNUM_RMAPi] =
 			be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAPi]);
 	pag->pagf_refcount_level = be32_to_cpu(agf->agf_refcount_level);
-	pag->pagf_init = 1;
+	set_bit(XFS_AGSTATE_AGF_INIT, &pag->pag_opstate);
 
 	return 0;
 }
@@ -434,7 +435,7 @@ xrep_agf(
 
 out_revert:
 	/* Mark the incore AGF state stale and revert the AGF. */
-	sc->sa.pag->pagf_init = 0;
+	clear_bit(XFS_AGSTATE_AGF_INIT, &sc->sa.pag->pag_opstate);
 	memcpy(agf, &old_agf, sizeof(old_agf));
 	return error;
 }
@@ -618,7 +619,7 @@ xrep_agfl_update_agf(
 	xfs_force_summary_recalc(sc->mp);
 
 	/* Update the AGF counters. */
-	if (sc->sa.pag->pagf_init)
+	if (xfs_perag_initialised_agf(sc->sa.pag))
 		sc->sa.pag->pagf_flcount = flcount;
 	agf->agf_flfirst = cpu_to_be32(0);
 	agf->agf_flcount = cpu_to_be32(flcount);
@@ -822,14 +823,15 @@ xrep_agi_init_header(
 	struct xfs_agi		*old_agi)
 {
 	struct xfs_agi		*agi = agi_bp->b_addr;
+	struct xfs_perag	*pag = sc->sa.pag;
 	struct xfs_mount	*mp = sc->mp;
 
 	memcpy(old_agi, agi, sizeof(*old_agi));
 	memset(agi, 0, BBTOB(agi_bp->b_length));
 	agi->agi_magicnum = cpu_to_be32(XFS_AGI_MAGIC);
 	agi->agi_versionnum = cpu_to_be32(XFS_AGI_VERSION);
-	agi->agi_seqno = cpu_to_be32(sc->sa.pag->pag_agno);
-	agi->agi_length = cpu_to_be32(sc->sa.pag->block_count);
+	agi->agi_seqno = cpu_to_be32(pag->pag_agno);
+	agi->agi_length = cpu_to_be32(pag->block_count);
 	agi->agi_newino = cpu_to_be32(NULLAGINO);
 	agi->agi_dirino = cpu_to_be32(NULLAGINO);
 	if (xfs_has_crc(mp))
@@ -840,8 +842,8 @@ xrep_agi_init_header(
 			sizeof(agi->agi_unlinked));
 
 	/* Mark the incore AGF data stale until we're done fixing things. */
-	ASSERT(sc->sa.pag->pagi_init);
-	sc->sa.pag->pagi_init = 0;
+	ASSERT(xfs_perag_initialised_agi(pag));
+	clear_bit(XFS_AGSTATE_AGI_INIT, &pag->pag_opstate);
 }
 
 /* Set btree root information in an AGI. */
@@ -873,8 +875,7 @@ xrep_agi_calc_from_btrees(
 	xfs_agino_t		freecount;
 	int			error;
 
-	cur = xfs_inobt_init_cursor(mp, sc->tp, agi_bp,
-			sc->sa.pag, XFS_BTNUM_INO);
+	cur = xfs_inobt_init_cursor(sc->sa.pag, sc->tp, agi_bp, XFS_BTNUM_INO);
 	error = xfs_ialloc_count_inodes(cur, &count, &freecount);
 	if (error)
 		goto err;
@@ -894,8 +895,8 @@ xrep_agi_calc_from_btrees(
 	if (xfs_has_finobt(mp) && xfs_has_inobtcounts(mp)) {
 		xfs_agblock_t	blocks;
 
-		cur = xfs_inobt_init_cursor(mp, sc->tp, agi_bp,
-				sc->sa.pag, XFS_BTNUM_FINO);
+		cur = xfs_inobt_init_cursor(sc->sa.pag, sc->tp, agi_bp,
+				XFS_BTNUM_FINO);
 		error = xfs_btree_count_blocks(cur, &blocks);
 		if (error)
 			goto err;
@@ -929,7 +930,7 @@ xrep_agi_commit_new(
 	pag = sc->sa.pag;
 	pag->pagi_count = be32_to_cpu(agi->agi_count);
 	pag->pagi_freecount = be32_to_cpu(agi->agi_freecount);
-	pag->pagi_init = 1;
+	set_bit(XFS_AGSTATE_AGI_INIT, &pag->pag_opstate);
 
 	return 0;
 }
@@ -994,7 +995,7 @@ xrep_agi(
 
 out_revert:
 	/* Mark the incore AGI state stale and revert the AGI. */
-	sc->sa.pag->pagi_init = 0;
+	clear_bit(XFS_AGSTATE_AGI_INIT, &sc->sa.pag->pag_opstate);
 	memcpy(agi, &old_agi, sizeof(old_agi));
 	return error;
 }
diff --git a/fs/xfs/scrub/bmap.c b/fs/xfs/scrub/bmap.c
index d50d0eab196abf..dbbc7037074c4c 100644
--- a/fs/xfs/scrub/bmap.c
+++ b/fs/xfs/scrub/bmap.c
@@ -662,7 +662,7 @@ xchk_bmap_check_rmaps(
 		error = xchk_bmap_check_ag_rmaps(sc, whichfork, pag);
 		if (error ||
 		    (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)) {
-			xfs_perag_put(pag);
+			xfs_perag_rele(pag);
 			return error;
 		}
 	}
diff --git a/fs/xfs/scrub/common.c b/fs/xfs/scrub/common.c
index 613260b04a3dc6..848a8e32e56f01 100644
--- a/fs/xfs/scrub/common.c
+++ b/fs/xfs/scrub/common.c
@@ -478,15 +478,15 @@ xchk_ag_btcur_init(
 	/* 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,
-				sa->pag, XFS_BTNUM_INO);
+		sa->ino_cur = xfs_inobt_init_cursor(sa->pag, sc->tp, sa->agi_bp,
+				XFS_BTNUM_INO);
 	}
 
 	/* Set up a finobt cursor for cross-referencing. */
 	if (sa->agi_bp && xfs_has_finobt(mp) &&
 	    xchk_ag_btree_healthy_enough(sc, sa->pag, XFS_BTNUM_FINO)) {
-		sa->fino_cur = xfs_inobt_init_cursor(mp, sc->tp, sa->agi_bp,
-				sa->pag, XFS_BTNUM_FINO);
+		sa->fino_cur = xfs_inobt_init_cursor(sa->pag, sc->tp, sa->agi_bp,
+				XFS_BTNUM_FINO);
 	}
 
 	/* Set up a rmapbt cursor for cross-referencing. */
@@ -636,6 +636,7 @@ xchk_get_inode(
 {
 	struct xfs_imap		imap;
 	struct xfs_mount	*mp = sc->mp;
+	struct xfs_perag	*pag;
 	struct xfs_inode	*ip_in = XFS_I(file_inode(sc->file));
 	struct xfs_inode	*ip = NULL;
 	int			error;
@@ -671,10 +672,14 @@ xchk_get_inode(
 		 * Otherwise, we really couldn't find it so tell userspace
 		 * that it no longer exists.
 		 */
-		error = xfs_imap(sc->mp, sc->tp, sc->sm->sm_ino, &imap,
-				XFS_IGET_UNTRUSTED | XFS_IGET_DONTCACHE);
-		if (error)
-			return -ENOENT;
+		pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, sc->sm->sm_ino));
+		if (pag) {
+			error = xfs_imap(pag, sc->tp, sc->sm->sm_ino, &imap,
+					XFS_IGET_UNTRUSTED | XFS_IGET_DONTCACHE);
+			xfs_perag_put(pag);
+			if (error)
+				return -ENOENT;
+		}
 		error = -EFSCORRUPTED;
 		fallthrough;
 	default:
diff --git a/fs/xfs/scrub/fscounters.c b/fs/xfs/scrub/fscounters.c
index 4777e7b89fdc69..f0c7f41897b904 100644
--- a/fs/xfs/scrub/fscounters.c
+++ b/fs/xfs/scrub/fscounters.c
@@ -86,7 +86,8 @@ xchk_fscount_warmup(
 	for_each_perag(mp, agno, pag) {
 		if (xchk_should_terminate(sc, &error))
 			break;
-		if (pag->pagi_init && pag->pagf_init)
+		if (xfs_perag_initialised_agi(pag) &&
+		    xfs_perag_initialised_agf(pag))
 			continue;
 
 		/* Lock both AG headers. */
@@ -101,7 +102,8 @@ xchk_fscount_warmup(
 		 * These are supposed to be initialized by the header read
 		 * function.
 		 */
-		if (!pag->pagi_init || !pag->pagf_init) {
+		if (!xfs_perag_initialised_agi(pag) ||
+		    !xfs_perag_initialised_agf(pag)) {
 			error = -EFSCORRUPTED;
 			break;
 		}
@@ -117,7 +119,7 @@ xchk_fscount_warmup(
 	if (agi_bp)
 		xfs_buf_relse(agi_bp);
 	if (pag)
-		xfs_perag_put(pag);
+		xfs_perag_rele(pag);
 	return error;
 }
 
@@ -220,7 +222,8 @@ retry:
 			break;
 
 		/* This somehow got unset since the warmup? */
-		if (!pag->pagi_init || !pag->pagf_init) {
+		if (!xfs_perag_initialised_agi(pag) ||
+		    !xfs_perag_initialised_agf(pag)) {
 			error = -EFSCORRUPTED;
 			break;
 		}
@@ -249,7 +252,7 @@ retry:
 
 	}
 	if (pag)
-		xfs_perag_put(pag);
+		xfs_perag_rele(pag);
 	if (error) {
 		xchk_set_incomplete(sc);
 		return error;
diff --git a/fs/xfs/scrub/repair.c b/fs/xfs/scrub/repair.c
index 4b92f9253ccd2c..1b71174ec0d6d4 100644
--- a/fs/xfs/scrub/repair.c
+++ b/fs/xfs/scrub/repair.c
@@ -206,7 +206,7 @@ xrep_calc_ag_resblks(
 		return 0;
 
 	pag = xfs_perag_get(mp, sm->sm_agno);
-	if (pag->pagi_init) {
+	if (xfs_perag_initialised_agi(pag)) {
 		/* Use in-core icount if possible. */
 		icount = pag->pagi_count;
 	} else {
@@ -326,15 +326,14 @@ xrep_alloc_ag_block(
 
 	args.tp = sc->tp;
 	args.mp = sc->mp;
+	args.pag = sc->sa.pag;
 	args.oinfo = *oinfo;
-	args.fsbno = XFS_AGB_TO_FSB(args.mp, sc->sa.pag->pag_agno, 0);
 	args.minlen = 1;
 	args.maxlen = 1;
 	args.prod = 1;
-	args.type = XFS_ALLOCTYPE_THIS_AG;
 	args.resv = resv;
 
-	error = xfs_alloc_vextent(&args);
+	error = xfs_alloc_vextent_this_ag(&args, sc->sa.pag->pag_agno);
 	if (error)
 		return error;
 	if (args.fsbno == NULLFSBLOCK)
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 867645b74d889d..a09dd260647927 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1410,7 +1410,7 @@ xfs_swap_extent_rmap(
 
 		/* Unmap the old blocks in the source file. */
 		while (tirec.br_blockcount) {
-			ASSERT(tp->t_firstblock == NULLFSBLOCK);
+			ASSERT(tp->t_highest_agno == NULLAGNUMBER);
 			trace_xfs_swap_extent_rmap_remap_piece(tip, &tirec);
 
 			/* Read extent from the source file */
diff --git a/fs/xfs/xfs_discard.c b/fs/xfs/xfs_discard.c
index bfc829c07f035f..afc4c78b9eed64 100644
--- a/fs/xfs/xfs_discard.c
+++ b/fs/xfs/xfs_discard.c
@@ -21,23 +21,20 @@
 
 STATIC int
 xfs_trim_extents(
-	struct xfs_mount	*mp,
-	xfs_agnumber_t		agno,
+	struct xfs_perag	*pag,
 	xfs_daddr_t		start,
 	xfs_daddr_t		end,
 	xfs_daddr_t		minlen,
 	uint64_t		*blocks_trimmed)
 {
+	struct xfs_mount	*mp = pag->pag_mount;
 	struct block_device	*bdev = mp->m_ddev_targp->bt_bdev;
 	struct xfs_btree_cur	*cur;
 	struct xfs_buf		*agbp;
 	struct xfs_agf		*agf;
-	struct xfs_perag	*pag;
 	int			error;
 	int			i;
 
-	pag = xfs_perag_get(mp, agno);
-
 	/*
 	 * Force out the log.  This means any transactions that might have freed
 	 * space before we take the AGF buffer lock are now on disk, and the
@@ -47,7 +44,7 @@ xfs_trim_extents(
 
 	error = xfs_alloc_read_agf(pag, NULL, 0, &agbp);
 	if (error)
-		goto out_put_perag;
+		return error;
 	agf = agbp->b_addr;
 
 	cur = xfs_allocbt_init_cursor(mp, NULL, agbp, pag, XFS_BTNUM_CNT);
@@ -71,10 +68,10 @@ xfs_trim_extents(
 
 		error = xfs_alloc_get_rec(cur, &fbno, &flen, &i);
 		if (error)
-			goto out_del_cursor;
+			break;
 		if (XFS_IS_CORRUPT(mp, i != 1)) {
 			error = -EFSCORRUPTED;
-			goto out_del_cursor;
+			break;
 		}
 		ASSERT(flen <= be32_to_cpu(agf->agf_longest));
 
@@ -83,15 +80,15 @@ xfs_trim_extents(
 		 * the format the range/len variables are supplied in by
 		 * userspace.
 		 */
-		dbno = XFS_AGB_TO_DADDR(mp, agno, fbno);
+		dbno = XFS_AGB_TO_DADDR(mp, pag->pag_agno, fbno);
 		dlen = XFS_FSB_TO_BB(mp, flen);
 
 		/*
 		 * Too small?  Give up.
 		 */
 		if (dlen < minlen) {
-			trace_xfs_discard_toosmall(mp, agno, fbno, flen);
-			goto out_del_cursor;
+			trace_xfs_discard_toosmall(mp, pag->pag_agno, fbno, flen);
+			break;
 		}
 
 		/*
@@ -100,7 +97,7 @@ xfs_trim_extents(
 		 * down partially overlapping ranges for now.
 		 */
 		if (dbno + dlen < start || dbno > end) {
-			trace_xfs_discard_exclude(mp, agno, fbno, flen);
+			trace_xfs_discard_exclude(mp, pag->pag_agno, fbno, flen);
 			goto next_extent;
 		}
 
@@ -109,32 +106,30 @@ xfs_trim_extents(
 		 * discard and try again the next time.
 		 */
 		if (xfs_extent_busy_search(mp, pag, fbno, flen)) {
-			trace_xfs_discard_busy(mp, agno, fbno, flen);
+			trace_xfs_discard_busy(mp, pag->pag_agno, fbno, flen);
 			goto next_extent;
 		}
 
-		trace_xfs_discard_extent(mp, agno, fbno, flen);
+		trace_xfs_discard_extent(mp, pag->pag_agno, fbno, flen);
 		error = blkdev_issue_discard(bdev, dbno, dlen, GFP_NOFS);
 		if (error)
-			goto out_del_cursor;
+			break;
 		*blocks_trimmed += flen;
 
 next_extent:
 		error = xfs_btree_decrement(cur, 0, &i);
 		if (error)
-			goto out_del_cursor;
+			break;
 
 		if (fatal_signal_pending(current)) {
 			error = -ERESTARTSYS;
-			goto out_del_cursor;
+			break;
 		}
 	}
 
 out_del_cursor:
 	xfs_btree_del_cursor(cur, error);
 	xfs_buf_relse(agbp);
-out_put_perag:
-	xfs_perag_put(pag);
 	return error;
 }
 
@@ -152,11 +147,12 @@ xfs_ioc_trim(
 	struct xfs_mount		*mp,
 	struct fstrim_range __user	*urange)
 {
+	struct xfs_perag	*pag;
 	unsigned int		granularity =
 		bdev_discard_granularity(mp->m_ddev_targp->bt_bdev);
 	struct fstrim_range	range;
 	xfs_daddr_t		start, end, minlen;
-	xfs_agnumber_t		start_agno, end_agno, agno;
+	xfs_agnumber_t		agno;
 	uint64_t		blocks_trimmed = 0;
 	int			error, last_error = 0;
 
@@ -193,18 +189,18 @@ xfs_ioc_trim(
 	end = start + BTOBBT(range.len) - 1;
 
 	if (end > XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1)
-		end = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)- 1;
-
-	start_agno = xfs_daddr_to_agno(mp, start);
-	end_agno = xfs_daddr_to_agno(mp, end);
+		end = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1;
 
-	for (agno = start_agno; agno <= end_agno; agno++) {
-		error = xfs_trim_extents(mp, agno, start, end, minlen,
+	agno = xfs_daddr_to_agno(mp, start);
+	for_each_perag_range(mp, agno, xfs_daddr_to_agno(mp, end), pag) {
+		error = xfs_trim_extents(pag, start, end, minlen,
 					  &blocks_trimmed);
 		if (error) {
 			last_error = error;
-			if (error == -ERESTARTSYS)
+			if (error == -ERESTARTSYS) {
+				xfs_perag_rele(pag);
 				break;
+			}
 		}
 	}
 
diff --git a/fs/xfs/xfs_filestream.c b/fs/xfs/xfs_filestream.c
index 34b21a29c39bc3..22c13933c8f80a 100644
--- a/fs/xfs/xfs_filestream.c
+++ b/fs/xfs/xfs_filestream.c
@@ -12,6 +12,7 @@
 #include "xfs_mount.h"
 #include "xfs_inode.h"
 #include "xfs_bmap.h"
+#include "xfs_bmap_util.h"
 #include "xfs_alloc.h"
 #include "xfs_mru_cache.h"
 #include "xfs_trace.h"
@@ -22,7 +23,7 @@
 
 struct xfs_fstrm_item {
 	struct xfs_mru_cache_elem	mru;
-	xfs_agnumber_t			ag; /* AG in use for this directory */
+	struct xfs_perag		*pag; /* AG in use for this directory */
 };
 
 enum xfs_fstrm_alloc {
@@ -30,117 +31,68 @@ enum xfs_fstrm_alloc {
 	XFS_PICK_LOWSPACE = 2,
 };
 
-/*
- * Allocation group filestream associations are tracked with per-ag atomic
- * counters.  These counters allow xfs_filestream_pick_ag() to tell whether a
- * particular AG already has active filestreams associated with it.
- */
-int
-xfs_filestream_peek_ag(
-	xfs_mount_t	*mp,
-	xfs_agnumber_t	agno)
-{
-	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 int
-xfs_filestream_get_ag(
-	xfs_mount_t	*mp,
-	xfs_agnumber_t	agno)
-{
-	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 void
-xfs_filestream_put_ag(
-	xfs_mount_t	*mp,
-	xfs_agnumber_t	agno)
-{
-	struct xfs_perag *pag;
-
-	pag = xfs_perag_get(mp, agno);
-	atomic_dec(&pag->pagf_fstrms);
-	xfs_perag_put(pag);
-}
-
 static void
 xfs_fstrm_free_func(
 	void			*data,
 	struct xfs_mru_cache_elem *mru)
 {
-	struct xfs_mount	*mp = data;
 	struct xfs_fstrm_item	*item =
 		container_of(mru, struct xfs_fstrm_item, mru);
+	struct xfs_perag	*pag = item->pag;
 
-	xfs_filestream_put_ag(mp, item->ag);
-	trace_xfs_filestream_free(mp, mru->key, item->ag);
+	trace_xfs_filestream_free(pag, mru->key);
+	atomic_dec(&pag->pagf_fstrms);
+	xfs_perag_rele(pag);
 
 	kmem_free(item);
 }
 
 /*
- * Scan the AGs starting at startag looking for an AG that isn't in use and has
- * at least minlen blocks free.
+ * Scan the AGs starting at start_agno looking for an AG that isn't in use and
+ * has at least minlen blocks free. If no AG is found to match the allocation
+ * requirements, pick the AG with the most free space in it.
  */
 static int
 xfs_filestream_pick_ag(
-	struct xfs_inode	*ip,
-	xfs_agnumber_t		startag,
-	xfs_agnumber_t		*agp,
+	struct xfs_alloc_arg	*args,
+	xfs_ino_t		pino,
+	xfs_agnumber_t		start_agno,
 	int			flags,
-	xfs_extlen_t		minlen)
+	xfs_extlen_t		*longest)
 {
-	struct xfs_mount	*mp = ip->i_mount;
-	struct xfs_fstrm_item	*item;
+	struct xfs_mount	*mp = args->mp;
 	struct xfs_perag	*pag;
-	xfs_extlen_t		longest, free = 0, minfree, maxfree = 0;
-	xfs_agnumber_t		ag, max_ag = NULLAGNUMBER;
-	int			err, trylock, nscan;
-
-	ASSERT(S_ISDIR(VFS_I(ip)->i_mode));
+	struct xfs_perag	*max_pag = NULL;
+	xfs_extlen_t		minlen = *longest;
+	xfs_extlen_t		free = 0, minfree, maxfree = 0;
+	xfs_agnumber_t		agno;
+	bool			first_pass = true;
+	int			err;
 
 	/* 2% of an AG's blocks must be free for it to be chosen. */
 	minfree = mp->m_sb.sb_agblocks / 50;
 
-	ag = startag;
-	*agp = NULLAGNUMBER;
-
-	/* For the first pass, don't sleep trying to init the per-AG. */
-	trylock = XFS_ALLOC_FLAG_TRYLOCK;
-
-	for (nscan = 0; 1; nscan++) {
-		trace_xfs_filestream_scan(mp, ip->i_ino, ag);
-
-		pag = xfs_perag_get(mp, ag);
-
-		if (!pag->pagf_init) {
-			err = xfs_alloc_read_agf(pag, NULL, trylock, NULL);
-			if (err) {
-				if (err != -EAGAIN) {
-					xfs_perag_put(pag);
-					return err;
-				}
-				/* Couldn't lock the AGF, skip this AG. */
-				goto next_ag;
-			}
+restart:
+	for_each_perag_wrap(mp, start_agno, agno, pag) {
+		trace_xfs_filestream_scan(pag, pino);
+		*longest = 0;
+		err = xfs_bmap_longest_free_extent(pag, NULL, longest);
+		if (err) {
+			xfs_perag_rele(pag);
+			if (err != -EAGAIN)
+				break;
+			/* Couldn't lock the AGF, skip this AG. */
+			err = 0;
+			continue;
 		}
 
 		/* Keep track of the AG with the most free blocks. */
 		if (pag->pagf_freeblks > maxfree) {
 			maxfree = pag->pagf_freeblks;
-			max_ag = ag;
+			if (max_pag)
+				xfs_perag_rele(max_pag);
+			atomic_inc(&pag->pag_active_ref);
+			max_pag = pag;
 		}
 
 		/*
@@ -149,93 +101,73 @@ xfs_filestream_pick_ag(
 		 * loop, and it guards against two filestreams being established
 		 * in the same AG as each other.
 		 */
-		if (xfs_filestream_get_ag(mp, ag) > 1) {
-			xfs_filestream_put_ag(mp, ag);
-			goto next_ag;
-		}
-
-		longest = xfs_alloc_longest_free_extent(pag,
-				xfs_alloc_min_freelist(mp, pag),
-				xfs_ag_resv_needed(pag, XFS_AG_RESV_NONE));
-		if (((minlen && longest >= minlen) ||
-		     (!minlen && pag->pagf_freeblks >= minfree)) &&
-		    (!pag->pagf_metadata || !(flags & XFS_PICK_USERDATA) ||
-		     (flags & XFS_PICK_LOWSPACE))) {
-
-			/* Break out, retaining the reference on the AG. */
-			free = pag->pagf_freeblks;
-			xfs_perag_put(pag);
-			*agp = ag;
-			break;
+		if (atomic_inc_return(&pag->pagf_fstrms) <= 1) {
+			if (((minlen && *longest >= minlen) ||
+			     (!minlen && pag->pagf_freeblks >= minfree)) &&
+			    (!xfs_perag_prefers_metadata(pag) ||
+			     !(flags & XFS_PICK_USERDATA) ||
+			     (flags & XFS_PICK_LOWSPACE))) {
+				/* Break out, retaining the reference on the AG. */
+				free = pag->pagf_freeblks;
+				break;
+			}
 		}
 
 		/* 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;
-
-		/* If a full pass of the AGs hasn't been done yet, continue. */
-		if (ag != startag)
-			continue;
+		atomic_dec(&pag->pagf_fstrms);
+	}
 
-		/* Allow sleeping in xfs_alloc_read_agf() on the 2nd pass. */
-		if (trylock != 0) {
-			trylock = 0;
-			continue;
+	if (err) {
+		xfs_perag_rele(pag);
+		if (max_pag)
+			xfs_perag_rele(max_pag);
+		return err;
+	}
+
+	if (!pag) {
+		/*
+		 * Allow a second pass to give xfs_bmap_longest_free_extent()
+		 * another attempt at locking AGFs that it might have skipped
+		 * over before we fail.
+		 */
+		if (first_pass) {
+			first_pass = false;
+			goto restart;
 		}
 
-		/* Finally, if lowspace wasn't set, set it for the 3rd pass. */
+		/*
+		 * We must be low on data space, so run a final lowspace
+		 * optimised selection pass if we haven't already.
+		 */
 		if (!(flags & XFS_PICK_LOWSPACE)) {
 			flags |= XFS_PICK_LOWSPACE;
-			continue;
+			goto restart;
 		}
 
 		/*
-		 * Take the AG with the most free space, regardless of whether
-		 * it's already in use by another filestream.
+		 * No unassociated AGs are available, so select the AG with the
+		 * most free space, regardless of whether it's already in use by
+		 * another filestream. It none suit, just use whatever AG we can
+		 * grab.
 		 */
-		if (max_ag != NULLAGNUMBER) {
-			xfs_filestream_get_ag(mp, max_ag);
+		if (!max_pag) {
+			for_each_perag_wrap(args->mp, 0, start_agno, args->pag)
+				break;
+			atomic_inc(&args->pag->pagf_fstrms);
+			*longest = 0;
+		} else {
+			pag = max_pag;
 			free = maxfree;
-			*agp = max_ag;
-			break;
+			atomic_inc(&pag->pagf_fstrms);
 		}
-
-		/* take AG 0 if none matched */
-		trace_xfs_filestream_pick(ip, *agp, free, nscan);
-		*agp = 0;
-		return 0;
-	}
-
-	trace_xfs_filestream_pick(ip, *agp, free, nscan);
-
-	if (*agp == NULLAGNUMBER)
-		return 0;
-
-	err = -ENOMEM;
-	item = kmem_alloc(sizeof(*item), KM_MAYFAIL);
-	if (!item)
-		goto out_put_ag;
-
-	item->ag = *agp;
-
-	err = xfs_mru_cache_insert(mp->m_filestream, ip->i_ino, &item->mru);
-	if (err) {
-		if (err == -EEXIST)
-			err = 0;
-		goto out_free_item;
+	} else if (max_pag) {
+		xfs_perag_rele(max_pag);
 	}
 
+	trace_xfs_filestream_pick(pag, pino, free);
+	args->pag = pag;
 	return 0;
 
-out_free_item:
-	kmem_free(item);
-out_put_ag:
-	xfs_filestream_put_ag(mp, *agp);
-	return err;
 }
 
 static struct xfs_inode *
@@ -263,104 +195,187 @@ out:
 }
 
 /*
- * Find the right allocation group for a file, either by finding an
- * existing file stream or creating a new one.
+ * Lookup the mru cache for an existing association. If one exists and we can
+ * use it, return with an active perag reference indicating that the allocation
+ * will proceed with that association.
  *
- * Returns NULLAGNUMBER in case of an error.
+ * If we have no association, or we cannot use the current one and have to
+ * destroy it, return with longest = 0 to tell the caller to create a new
+ * association.
  */
-xfs_agnumber_t
-xfs_filestream_lookup_ag(
-	struct xfs_inode	*ip)
+static int
+xfs_filestream_lookup_association(
+	struct xfs_bmalloca	*ap,
+	struct xfs_alloc_arg	*args,
+	xfs_ino_t		pino,
+	xfs_extlen_t		*longest)
 {
-	struct xfs_mount	*mp = ip->i_mount;
-	struct xfs_inode	*pip = NULL;
-	xfs_agnumber_t		startag, ag = NULLAGNUMBER;
+	struct xfs_mount	*mp = args->mp;
+	struct xfs_perag	*pag;
 	struct xfs_mru_cache_elem *mru;
+	int			error = 0;
 
-	ASSERT(S_ISREG(VFS_I(ip)->i_mode));
-
-	pip = xfs_filestream_get_parent(ip);
-	if (!pip)
-		return NULLAGNUMBER;
+	*longest = 0;
+	mru = xfs_mru_cache_lookup(mp->m_filestream, pino);
+	if (!mru)
+		return 0;
+	/*
+	 * Grab the pag and take an extra active reference for the caller whilst
+	 * the mru item cannot go away. This means we'll pin the perag with
+	 * the reference we get here even if the filestreams association is torn
+	 * down immediately after we mark the lookup as done.
+	 */
+	pag = container_of(mru, struct xfs_fstrm_item, mru)->pag;
+	atomic_inc(&pag->pag_active_ref);
+	xfs_mru_cache_done(mp->m_filestream);
 
-	mru = xfs_mru_cache_lookup(mp->m_filestream, pip->i_ino);
-	if (mru) {
-		ag = container_of(mru, struct xfs_fstrm_item, mru)->ag;
-		xfs_mru_cache_done(mp->m_filestream);
+	trace_xfs_filestream_lookup(pag, ap->ip->i_ino);
 
-		trace_xfs_filestream_lookup(mp, ip->i_ino, ag);
-		goto out;
-	}
+	ap->blkno = XFS_AGB_TO_FSB(args->mp, pag->pag_agno, 0);
+	xfs_bmap_adjacent(ap);
 
 	/*
-	 * Set the starting AG using the rotor for inode32, otherwise
-	 * use the directory inode's AG.
+	 * If there is very little free space before we start a filestreams
+	 * allocation, we're almost guaranteed to fail to find a large enough
+	 * free space available so just use the cached AG.
 	 */
-	if (xfs_is_inode32(mp)) {
-		xfs_agnumber_t	 rotorstep = xfs_rotorstep;
-		startag = (mp->m_agfrotor / rotorstep) % mp->m_sb.sb_agcount;
-		mp->m_agfrotor = (mp->m_agfrotor + 1) %
-		                 (mp->m_sb.sb_agcount * rotorstep);
-	} else
-		startag = XFS_INO_TO_AGNO(mp, pip->i_ino);
+	if (ap->tp->t_flags & XFS_TRANS_LOWMODE) {
+		*longest = 1;
+		goto out_done;
+	}
 
-	if (xfs_filestream_pick_ag(pip, startag, &ag, 0, 0))
-		ag = NULLAGNUMBER;
-out:
-	xfs_irele(pip);
-	return ag;
+	error = xfs_bmap_longest_free_extent(pag, args->tp, longest);
+	if (error == -EAGAIN)
+		error = 0;
+	if (error || *longest < args->maxlen) {
+		/* We aren't going to use this perag */
+		*longest = 0;
+		xfs_perag_rele(pag);
+		return error;
+	}
+
+out_done:
+	args->pag = pag;
+	return 0;
 }
 
-/*
- * Pick a new allocation group for the current file and its file stream.
- *
- * This is called when the allocator can't find a suitable extent in the
- * current AG, and we have to move the stream into a new AG with more space.
- */
-int
-xfs_filestream_new_ag(
+static int
+xfs_filestream_create_association(
 	struct xfs_bmalloca	*ap,
-	xfs_agnumber_t		*agp)
+	struct xfs_alloc_arg	*args,
+	xfs_ino_t		pino,
+	xfs_extlen_t		*longest)
 {
-	struct xfs_inode	*ip = ap->ip, *pip;
-	struct xfs_mount	*mp = ip->i_mount;
-	xfs_extlen_t		minlen = ap->length;
-	xfs_agnumber_t		startag = 0;
-	int			flags = 0;
-	int			err = 0;
+	struct xfs_mount	*mp = args->mp;
 	struct xfs_mru_cache_elem *mru;
+	struct xfs_fstrm_item	*item;
+	xfs_agnumber_t		agno = XFS_INO_TO_AGNO(mp, pino);
+	int			flags = 0;
+	int			error;
 
-	*agp = NULLAGNUMBER;
-
-	pip = xfs_filestream_get_parent(ip);
-	if (!pip)
-		goto exit;
-
-	mru = xfs_mru_cache_remove(mp->m_filestream, pip->i_ino);
+	/* Changing parent AG association now, so remove the existing one. */
+	mru = xfs_mru_cache_remove(mp->m_filestream, pino);
 	if (mru) {
 		struct xfs_fstrm_item *item =
 			container_of(mru, struct xfs_fstrm_item, mru);
-		startag = (item->ag + 1) % mp->m_sb.sb_agcount;
+
+		agno = (item->pag->pag_agno + 1) % mp->m_sb.sb_agcount;
+		xfs_fstrm_free_func(mp, mru);
+	} else if (xfs_is_inode32(mp)) {
+		xfs_agnumber_t	 rotorstep = xfs_rotorstep;
+
+		agno = (mp->m_agfrotor / rotorstep) % mp->m_sb.sb_agcount;
+		mp->m_agfrotor = (mp->m_agfrotor + 1) %
+				 (mp->m_sb.sb_agcount * rotorstep);
 	}
 
+	ap->blkno = XFS_AGB_TO_FSB(args->mp, agno, 0);
+	xfs_bmap_adjacent(ap);
+
 	if (ap->datatype & XFS_ALLOC_USERDATA)
 		flags |= XFS_PICK_USERDATA;
 	if (ap->tp->t_flags & XFS_TRANS_LOWMODE)
 		flags |= XFS_PICK_LOWSPACE;
 
-	err = xfs_filestream_pick_ag(pip, startag, agp, flags, minlen);
+	*longest = ap->length;
+	error = xfs_filestream_pick_ag(args, pino, agno, flags, longest);
+	if (error)
+		return error;
 
 	/*
-	 * Only free the item here so we skip over the old AG earlier.
+	 * We are going to use this perag now, so create an assoication for it.
+	 * xfs_filestream_pick_ag() has already bumped the perag fstrms counter
+	 * for us, so all we need to do here is take another active reference to
+	 * the perag for the cached association.
+	 *
+	 * If we fail to store the association, we need to drop the fstrms
+	 * counter as well as drop the perag reference we take here for the
+	 * item. We do not need to return an error for this failure - as long as
+	 * we return a referenced AG, the allocation can still go ahead just
+	 * fine.
 	 */
-	if (mru)
-		xfs_fstrm_free_func(mp, mru);
+	item = kmem_alloc(sizeof(*item), KM_MAYFAIL);
+	if (!item)
+		goto out_put_fstrms;
+
+	atomic_inc(&args->pag->pag_active_ref);
+	item->pag = args->pag;
+	error = xfs_mru_cache_insert(mp->m_filestream, pino, &item->mru);
+	if (error)
+		goto out_free_item;
+	return 0;
+
+out_free_item:
+	xfs_perag_rele(item->pag);
+	kmem_free(item);
+out_put_fstrms:
+	atomic_dec(&args->pag->pagf_fstrms);
+	return 0;
+}
+
+/*
+ * Search for an allocation group with a single extent large enough for
+ * the request. First we look for an existing association and use that if it
+ * is found. Otherwise, we create a new association by selecting an AG that fits
+ * the allocation criteria.
+ *
+ * We return with a referenced perag in args->pag to indicate which AG we are
+ * allocating into or an error with no references held.
+ */
+int
+xfs_filestream_select_ag(
+	struct xfs_bmalloca	*ap,
+	struct xfs_alloc_arg	*args,
+	xfs_extlen_t		*longest)
+{
+	struct xfs_mount	*mp = args->mp;
+	struct xfs_inode	*pip;
+	xfs_ino_t		ino = 0;
+	int			error = 0;
+
+	*longest = 0;
+	args->total = ap->total;
+	pip = xfs_filestream_get_parent(ap->ip);
+	if (pip) {
+		ino = pip->i_ino;
+		error = xfs_filestream_lookup_association(ap, args, ino,
+				longest);
+		xfs_irele(pip);
+		if (error)
+			return error;
+		if (*longest >= args->maxlen)
+			goto out_select;
+		if (ap->tp->t_flags & XFS_TRANS_LOWMODE)
+			goto out_select;
+	}
+
+	error = xfs_filestream_create_association(ap, args, ino, longest);
+	if (error)
+		return error;
 
-	xfs_irele(pip);
-exit:
-	if (*agp == NULLAGNUMBER)
-		*agp = 0;
-	return err;
+out_select:
+	ap->blkno = XFS_AGB_TO_FSB(mp, args->pag->pag_agno, 0);
+	return 0;
 }
 
 void
diff --git a/fs/xfs/xfs_filestream.h b/fs/xfs/xfs_filestream.h
index 403226ebb80bb3..84149ed0e3402a 100644
--- a/fs/xfs/xfs_filestream.h
+++ b/fs/xfs/xfs_filestream.h
@@ -9,13 +9,13 @@
 struct xfs_mount;
 struct xfs_inode;
 struct xfs_bmalloca;
+struct xfs_alloc_arg;
 
 int xfs_filestream_mount(struct xfs_mount *mp);
 void xfs_filestream_unmount(struct xfs_mount *mp);
 void xfs_filestream_deassociate(struct xfs_inode *ip);
-xfs_agnumber_t xfs_filestream_lookup_ag(struct xfs_inode *ip);
-int xfs_filestream_new_ag(struct xfs_bmalloca *ap, xfs_agnumber_t *agp);
-int xfs_filestream_peek_ag(struct xfs_mount *mp, xfs_agnumber_t agno);
+int xfs_filestream_select_ag(struct xfs_bmalloca *ap,
+		struct xfs_alloc_arg *args, xfs_extlen_t *blen);
 
 static inline int
 xfs_inode_is_filestream(
diff --git a/fs/xfs/xfs_fsmap.c b/fs/xfs/xfs_fsmap.c
index 88a88506ffffe4..59e7d1a14b6724 100644
--- a/fs/xfs/xfs_fsmap.c
+++ b/fs/xfs/xfs_fsmap.c
@@ -688,11 +688,11 @@ __xfs_getfsmap_datadev(
 		info->agf_bp = NULL;
 	}
 	if (info->pag) {
-		xfs_perag_put(info->pag);
+		xfs_perag_rele(info->pag);
 		info->pag = NULL;
 	} else if (pag) {
 		/* loop termination case */
-		xfs_perag_put(pag);
+		xfs_perag_rele(pag);
 	}
 
 	return error;
@@ -761,6 +761,7 @@ xfs_getfsmap_datadev_bnobt(
 {
 	struct xfs_alloc_rec_incore	akeys[2];
 
+	memset(akeys, 0, sizeof(akeys));
 	info->missing_owner = XFS_FMR_OWN_UNKNOWN;
 	return __xfs_getfsmap_datadev(tp, keys, info,
 			xfs_getfsmap_datadev_bnobt_query, &akeys[0]);
diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index ddeaccc04aec94..c9a7e270a4286b 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -255,7 +255,7 @@ xfs_perag_set_inode_tag(
 		break;
 	}
 
-	trace_xfs_perag_set_inode_tag(mp, pag->pag_agno, tag, _RET_IP_);
+	trace_xfs_perag_set_inode_tag(pag, _RET_IP_);
 }
 
 /* Clear a tag on both the AG incore inode tree and the AG radix tree. */
@@ -289,7 +289,7 @@ xfs_perag_clear_inode_tag(
 	radix_tree_tag_clear(&mp->m_perag_tree, pag->pag_agno, tag);
 	spin_unlock(&mp->m_perag_lock);
 
-	trace_xfs_perag_clear_inode_tag(mp, pag->pag_agno, tag, _RET_IP_);
+	trace_xfs_perag_clear_inode_tag(pag, _RET_IP_);
 }
 
 /*
@@ -586,7 +586,7 @@ xfs_iget_cache_miss(
 	if (!ip)
 		return -ENOMEM;
 
-	error = xfs_imap(mp, tp, ip->i_ino, &ip->i_imap, flags);
+	error = xfs_imap(pag, tp, ip->i_ino, &ip->i_imap, flags);
 	if (error)
 		goto out_destroy;
 
@@ -1767,7 +1767,7 @@ xfs_icwalk(
 		if (error) {
 			last_error = error;
 			if (error == -EFSCORRUPTED) {
-				xfs_perag_put(pag);
+				xfs_perag_rele(pag);
 				break;
 			}
 		}
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 7f1d715faab527..5808abab786c79 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1367,7 +1367,7 @@ xfs_itruncate_extents_flags(
 
 	unmap_len = XFS_MAX_FILEOFF - first_unmap_block + 1;
 	while (unmap_len > 0) {
-		ASSERT(tp->t_firstblock == NULLFSBLOCK);
+		ASSERT(tp->t_highest_agno == NULLAGNUMBER);
 		error = __xfs_bunmapi(tp, ip, first_unmap_block, &unmap_len,
 				flags, XFS_ITRUNC_MAX_EXTENTS);
 		if (error)
diff --git a/fs/xfs/xfs_iwalk.c b/fs/xfs/xfs_iwalk.c
index 7558486f49371c..21be93bf006dd6 100644
--- a/fs/xfs/xfs_iwalk.c
+++ b/fs/xfs/xfs_iwalk.c
@@ -275,7 +275,7 @@ xfs_iwalk_ag_start(
 
 	/* Set up a fresh cursor and empty the inobt cache. */
 	iwag->nr_recs = 0;
-	error = xfs_inobt_cur(mp, tp, pag, XFS_BTNUM_INO, curpp, agi_bpp);
+	error = xfs_inobt_cur(pag, tp, XFS_BTNUM_INO, curpp, agi_bpp);
 	if (error)
 		return error;
 
@@ -390,7 +390,7 @@ xfs_iwalk_run_callbacks(
 	}
 
 	/* ...and recreate the cursor just past where we left off. */
-	error = xfs_inobt_cur(mp, iwag->tp, iwag->pag, XFS_BTNUM_INO, curpp,
+	error = xfs_inobt_cur(iwag->pag, iwag->tp, XFS_BTNUM_INO, curpp,
 			agi_bpp);
 	if (error)
 		return error;
@@ -591,7 +591,7 @@ xfs_iwalk(
 	}
 
 	if (iwag.pag)
-		xfs_perag_put(pag);
+		xfs_perag_rele(pag);
 	xfs_iwalk_free(&iwag);
 	return error;
 }
@@ -683,7 +683,7 @@ xfs_iwalk_threaded(
 			break;
 	}
 	if (pag)
-		xfs_perag_put(pag);
+		xfs_perag_rele(pag);
 	if (polled)
 		xfs_pwork_poll(&pctl);
 	return xfs_pwork_destroy(&pctl);
@@ -776,7 +776,7 @@ xfs_inobt_walk(
 	}
 
 	if (iwag.pag)
-		xfs_perag_put(pag);
+		xfs_perag_rele(pag);
 	xfs_iwalk_free(&iwag);
 	return error;
 }
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 8aca2cc173ac1d..f3269c0626f057 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -210,8 +210,7 @@ typedef struct xfs_mount {
 	struct xfs_error_cfg	m_error_cfg[XFS_ERR_CLASS_MAX][XFS_ERR_ERRNO_MAX];
 	struct xstats		m_stats;	/* per-fs stats */
 	xfs_agnumber_t		m_agfrotor;	/* last ag where space found */
-	xfs_agnumber_t		m_agirotor;	/* last ag dir inode alloced */
-	spinlock_t		m_agirotor_lock;/* .. and lock protecting it */
+	atomic_t		m_agirotor;	/* last ag dir inode alloced */
 
 	/* Memory shrinker to throttle and reprioritize inodegc */
 	struct shrinker		m_inodegc_shrinker;
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 5535778a98f925..f5dc46ce980311 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -610,7 +610,7 @@ xfs_reflink_cancel_cow_blocks(
 			if (error)
 				break;
 		} else if (del.br_state == XFS_EXT_UNWRITTEN || cancel_real) {
-			ASSERT((*tpp)->t_firstblock == NULLFSBLOCK);
+			ASSERT((*tpp)->t_highest_agno == NULLAGNUMBER);
 
 			/* Free the CoW orphan record. */
 			xfs_refcount_free_cow_extent(*tpp, del.br_startblock,
@@ -927,7 +927,7 @@ xfs_reflink_recover_cow(
 	for_each_perag(mp, agno, pag) {
 		error = xfs_refcount_recover_cow_leftovers(mp, pag);
 		if (error) {
-			xfs_perag_put(pag);
+			xfs_perag_rele(pag);
 			break;
 		}
 	}
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 0c4b73e9b29d29..2479b5cbd75ecf 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -247,6 +247,32 @@ xfs_fs_show_options(
 	return 0;
 }
 
+static bool
+xfs_set_inode_alloc_perag(
+	struct xfs_perag	*pag,
+	xfs_ino_t		ino,
+	xfs_agnumber_t		max_metadata)
+{
+	if (!xfs_is_inode32(pag->pag_mount)) {
+		set_bit(XFS_AGSTATE_ALLOWS_INODES, &pag->pag_opstate);
+		clear_bit(XFS_AGSTATE_PREFERS_METADATA, &pag->pag_opstate);
+		return false;
+	}
+
+	if (ino > XFS_MAXINUMBER_32) {
+		clear_bit(XFS_AGSTATE_ALLOWS_INODES, &pag->pag_opstate);
+		clear_bit(XFS_AGSTATE_PREFERS_METADATA, &pag->pag_opstate);
+		return false;
+	}
+
+	set_bit(XFS_AGSTATE_ALLOWS_INODES, &pag->pag_opstate);
+	if (pag->pag_agno < max_metadata)
+		set_bit(XFS_AGSTATE_PREFERS_METADATA, &pag->pag_opstate);
+	else
+		clear_bit(XFS_AGSTATE_PREFERS_METADATA, &pag->pag_opstate);
+	return true;
+}
+
 /*
  * Set parameters for inode allocation heuristics, taking into account
  * filesystem size and inode32/inode64 mount options; i.e. specifically
@@ -310,24 +336,8 @@ xfs_set_inode_alloc(
 		ino = XFS_AGINO_TO_INO(mp, index, agino);
 
 		pag = xfs_perag_get(mp, index);
-
-		if (xfs_is_inode32(mp)) {
-			if (ino > XFS_MAXINUMBER_32) {
-				pag->pagi_inodeok = 0;
-				pag->pagf_metadata = 0;
-			} else {
-				pag->pagi_inodeok = 1;
-				maxagi++;
-				if (index < max_metadata)
-					pag->pagf_metadata = 1;
-				else
-					pag->pagf_metadata = 0;
-			}
-		} else {
-			pag->pagi_inodeok = 1;
-			pag->pagf_metadata = 0;
-		}
-
+		if (xfs_set_inode_alloc_perag(pag, ino, max_metadata))
+			maxagi++;
 		xfs_perag_put(pag);
 	}
 
@@ -1922,7 +1932,6 @@ static int xfs_init_fs_context(
 		return -ENOMEM;
 
 	spin_lock_init(&mp->m_sb_lock);
-	spin_lock_init(&mp->m_agirotor_lock);
 	INIT_RADIX_TREE(&mp->m_perag_tree, GFP_ATOMIC);
 	spin_lock_init(&mp->m_perag_lock);
 	mutex_init(&mp->m_growlock);
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 6b0e9ae7c513c5..7dc0fd6a650474 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -74,6 +74,7 @@ struct xfs_inobt_rec_incore;
 union xfs_btree_ptr;
 struct xfs_dqtrx;
 struct xfs_icwalk;
+struct xfs_perag;
 
 #define XFS_ATTR_FILTER_FLAGS \
 	{ XFS_ATTR_ROOT,	"ROOT" }, \
@@ -159,36 +160,40 @@ TRACE_EVENT(xlog_intent_recovery_failed,
 );
 
 DECLARE_EVENT_CLASS(xfs_perag_class,
-	TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno, int refcount,
-		 unsigned long caller_ip),
-	TP_ARGS(mp, agno, refcount, caller_ip),
+	TP_PROTO(struct xfs_perag *pag, unsigned long caller_ip),
+	TP_ARGS(pag, caller_ip),
 	TP_STRUCT__entry(
 		__field(dev_t, dev)
 		__field(xfs_agnumber_t, agno)
 		__field(int, refcount)
+		__field(int, active_refcount)
 		__field(unsigned long, caller_ip)
 	),
 	TP_fast_assign(
-		__entry->dev = mp->m_super->s_dev;
-		__entry->agno = agno;
-		__entry->refcount = refcount;
+		__entry->dev = pag->pag_mount->m_super->s_dev;
+		__entry->agno = pag->pag_agno;
+		__entry->refcount = atomic_read(&pag->pag_ref);
+		__entry->active_refcount = atomic_read(&pag->pag_active_ref);
 		__entry->caller_ip = caller_ip;
 	),
-	TP_printk("dev %d:%d agno 0x%x refcount %d caller %pS",
+	TP_printk("dev %d:%d agno 0x%x passive refs %d active refs %d caller %pS",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  __entry->agno,
 		  __entry->refcount,
+		  __entry->active_refcount,
 		  (char *)__entry->caller_ip)
 );
 
 #define DEFINE_PERAG_REF_EVENT(name)	\
 DEFINE_EVENT(xfs_perag_class, 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_PROTO(struct xfs_perag *pag, unsigned long caller_ip), \
+	TP_ARGS(pag, caller_ip))
 DEFINE_PERAG_REF_EVENT(xfs_perag_get);
 DEFINE_PERAG_REF_EVENT(xfs_perag_get_tag);
 DEFINE_PERAG_REF_EVENT(xfs_perag_put);
+DEFINE_PERAG_REF_EVENT(xfs_perag_grab);
+DEFINE_PERAG_REF_EVENT(xfs_perag_grab_tag);
+DEFINE_PERAG_REF_EVENT(xfs_perag_rele);
 DEFINE_PERAG_REF_EVENT(xfs_perag_set_inode_tag);
 DEFINE_PERAG_REF_EVENT(xfs_perag_clear_inode_tag);
 
@@ -634,8 +639,8 @@ DEFINE_BUF_ITEM_EVENT(xfs_trans_bhold_release);
 DEFINE_BUF_ITEM_EVENT(xfs_trans_binval);
 
 DECLARE_EVENT_CLASS(xfs_filestream_class,
-	TP_PROTO(struct xfs_mount *mp, xfs_ino_t ino, xfs_agnumber_t agno),
-	TP_ARGS(mp, ino, agno),
+	TP_PROTO(struct xfs_perag *pag, xfs_ino_t ino),
+	TP_ARGS(pag, ino),
 	TP_STRUCT__entry(
 		__field(dev_t, dev)
 		__field(xfs_ino_t, ino)
@@ -643,10 +648,10 @@ DECLARE_EVENT_CLASS(xfs_filestream_class,
 		__field(int, streams)
 	),
 	TP_fast_assign(
-		__entry->dev = mp->m_super->s_dev;
+		__entry->dev = pag->pag_mount->m_super->s_dev;
 		__entry->ino = ino;
-		__entry->agno = agno;
-		__entry->streams = xfs_filestream_peek_ag(mp, agno);
+		__entry->agno = pag->pag_agno;
+		__entry->streams = atomic_read(&pag->pagf_fstrms);
 	),
 	TP_printk("dev %d:%d ino 0x%llx agno 0x%x streams %d",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
@@ -656,39 +661,40 @@ DECLARE_EVENT_CLASS(xfs_filestream_class,
 )
 #define DEFINE_FILESTREAM_EVENT(name) \
 DEFINE_EVENT(xfs_filestream_class, name, \
-	TP_PROTO(struct xfs_mount *mp, xfs_ino_t ino, xfs_agnumber_t agno), \
-	TP_ARGS(mp, ino, agno))
+	TP_PROTO(struct xfs_perag *pag, xfs_ino_t ino), \
+	TP_ARGS(pag, ino))
 DEFINE_FILESTREAM_EVENT(xfs_filestream_free);
 DEFINE_FILESTREAM_EVENT(xfs_filestream_lookup);
 DEFINE_FILESTREAM_EVENT(xfs_filestream_scan);
 
 TRACE_EVENT(xfs_filestream_pick,
-	TP_PROTO(struct xfs_inode *ip, xfs_agnumber_t agno,
-		 xfs_extlen_t free, int nscan),
-	TP_ARGS(ip, agno, free, nscan),
+	TP_PROTO(struct xfs_perag *pag, xfs_ino_t ino, xfs_extlen_t free),
+	TP_ARGS(pag, ino, free),
 	TP_STRUCT__entry(
 		__field(dev_t, dev)
 		__field(xfs_ino_t, ino)
 		__field(xfs_agnumber_t, agno)
 		__field(int, streams)
 		__field(xfs_extlen_t, free)
-		__field(int, nscan)
 	),
 	TP_fast_assign(
-		__entry->dev = VFS_I(ip)->i_sb->s_dev;
-		__entry->ino = ip->i_ino;
-		__entry->agno = agno;
-		__entry->streams = xfs_filestream_peek_ag(ip->i_mount, agno);
+		__entry->dev = pag->pag_mount->m_super->s_dev;
+		__entry->ino = ino;
+		if (pag) {
+			__entry->agno = pag->pag_agno;
+			__entry->streams = atomic_read(&pag->pagf_fstrms);
+		} else {
+			__entry->agno = NULLAGNUMBER;
+			__entry->streams = 0;
+		}
 		__entry->free = free;
-		__entry->nscan = nscan;
 	),
-	TP_printk("dev %d:%d ino 0x%llx agno 0x%x streams %d free %d nscan %d",
+	TP_printk("dev %d:%d ino 0x%llx agno 0x%x streams %d free %d",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  __entry->ino,
 		  __entry->agno,
 		  __entry->streams,
-		  __entry->free,
-		  __entry->nscan)
+		  __entry->free)
 );
 
 DECLARE_EVENT_CLASS(xfs_lock_class,
@@ -1795,13 +1801,11 @@ DECLARE_EVENT_CLASS(xfs_alloc_class,
 		__field(xfs_extlen_t, alignment)
 		__field(xfs_extlen_t, minalignslop)
 		__field(xfs_extlen_t, len)
-		__field(short, type)
-		__field(short, otype)
 		__field(char, wasdel)
 		__field(char, wasfromfl)
 		__field(int, resv)
 		__field(int, datatype)
-		__field(xfs_fsblock_t, firstblock)
+		__field(xfs_agnumber_t, highest_agno)
 	),
 	TP_fast_assign(
 		__entry->dev = args->mp->m_super->s_dev;
@@ -1816,18 +1820,16 @@ DECLARE_EVENT_CLASS(xfs_alloc_class,
 		__entry->alignment = args->alignment;
 		__entry->minalignslop = args->minalignslop;
 		__entry->len = args->len;
-		__entry->type = args->type;
-		__entry->otype = args->otype;
 		__entry->wasdel = args->wasdel;
 		__entry->wasfromfl = args->wasfromfl;
 		__entry->resv = args->resv;
 		__entry->datatype = args->datatype;
-		__entry->firstblock = args->tp->t_firstblock;
+		__entry->highest_agno = args->tp->t_highest_agno;
 	),
 	TP_printk("dev %d:%d agno 0x%x agbno 0x%x minlen %u maxlen %u mod %u "
 		  "prod %u minleft %u total %u alignment %u minalignslop %u "
-		  "len %u type %s otype %s wasdel %d wasfromfl %d resv %d "
-		  "datatype 0x%x firstblock 0x%llx",
+		  "len %u wasdel %d wasfromfl %d resv %d "
+		  "datatype 0x%x highest_agno 0x%x",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  __entry->agno,
 		  __entry->agbno,
@@ -1840,13 +1842,11 @@ DECLARE_EVENT_CLASS(xfs_alloc_class,
 		  __entry->alignment,
 		  __entry->minalignslop,
 		  __entry->len,
-		  __print_symbolic(__entry->type, XFS_ALLOC_TYPES),
-		  __print_symbolic(__entry->otype, XFS_ALLOC_TYPES),
 		  __entry->wasdel,
 		  __entry->wasfromfl,
 		  __entry->resv,
 		  __entry->datatype,
-		  (unsigned long long)__entry->firstblock)
+		  __entry->highest_agno)
 )
 
 #define DEFINE_ALLOC_EVENT(name) \
@@ -1877,6 +1877,7 @@ DEFINE_ALLOC_EVENT(xfs_alloc_small_notenough);
 DEFINE_ALLOC_EVENT(xfs_alloc_small_done);
 DEFINE_ALLOC_EVENT(xfs_alloc_small_error);
 DEFINE_ALLOC_EVENT(xfs_alloc_vextent_badargs);
+DEFINE_ALLOC_EVENT(xfs_alloc_vextent_skip_deadlock);
 DEFINE_ALLOC_EVENT(xfs_alloc_vextent_nofix);
 DEFINE_ALLOC_EVENT(xfs_alloc_vextent_noagbp);
 DEFINE_ALLOC_EVENT(xfs_alloc_vextent_loopfailed);
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index 7bd16fbff53410..8afc0c080861d5 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -102,7 +102,7 @@ xfs_trans_dup(
 	INIT_LIST_HEAD(&ntp->t_items);
 	INIT_LIST_HEAD(&ntp->t_busy);
 	INIT_LIST_HEAD(&ntp->t_dfops);
-	ntp->t_firstblock = NULLFSBLOCK;
+	ntp->t_highest_agno = NULLAGNUMBER;
 
 	ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
 	ASSERT(tp->t_ticket != NULL);
@@ -278,7 +278,7 @@ retry:
 	INIT_LIST_HEAD(&tp->t_items);
 	INIT_LIST_HEAD(&tp->t_busy);
 	INIT_LIST_HEAD(&tp->t_dfops);
-	tp->t_firstblock = NULLFSBLOCK;
+	tp->t_highest_agno = NULLAGNUMBER;
 
 	error = xfs_trans_reserve(tp, resp, blocks, rtextents);
 	if (error == -ENOSPC && want_retry) {
@@ -1078,10 +1078,10 @@ xfs_trans_cancel(
 	/*
 	 * It's never valid to cancel a transaction with deferred ops attached,
 	 * because the transaction is effectively dirty.  Complain about this
-	 * loudly before freeing the in-memory defer items.
+	 * loudly before freeing the in-memory defer items and shutting down the
+	 * filesystem.
 	 */
 	if (!list_empty(&tp->t_dfops)) {
-		ASSERT(xfs_is_shutdown(mp) || list_empty(&tp->t_dfops));
 		ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
 		dirty = true;
 		xfs_defer_cancel(tp);
diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h
index 55819785941cc4..6e3646d524ceb6 100644
--- a/fs/xfs/xfs_trans.h
+++ b/fs/xfs/xfs_trans.h
@@ -132,7 +132,7 @@ typedef struct xfs_trans {
 	unsigned int		t_rtx_res;	/* # of rt extents resvd */
 	unsigned int		t_rtx_res_used;	/* # of resvd rt extents used */
 	unsigned int		t_flags;	/* misc flags */
-	xfs_fsblock_t		t_firstblock;	/* first block allocated */
+	xfs_agnumber_t		t_highest_agno;	/* highest AGF locked */
 	struct xlog_ticket	*t_ticket;	/* log mgr ticket */
 	struct xfs_mount	*t_mountp;	/* ptr to fs mount struct */
 	struct xfs_dquot_acct   *t_dqinfo;	/* acctg info for dquots */