Merge tag 'xfs-perag-conv-5.20' of...

Merge tag 'xfs-perag-conv-5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs into xfs-5.20-mergeA

xfs: per-ag conversions for 5.20

This series drives the perag down into the AGI, AGF and AGFL access
routines and unifies the perag structure initialisation with the
high level AG header read functions. This largely replaces the
xfs_mount/agno pair that is passed to all these functions with a
perag, and in most places we already have a perag ready to pass in.
There are a few places where perags need to be grabbed before
reading the AG header buffers - some of these will need to be driven
to higher layers to ensure we can run operations on AGs without
getting stuck part way through waiting on a perag reference.

The latter section of this patchset moves some of the AG geometry
information from the xfs_mount to the xfs_perag, and starts
converting code that requires geometry validation to use a perag
instead of a mount and having to extract the AGNO from the object
location. This also allows us to store the AG size in the perag and
then we can stop having to compare the agno against sb_agcount to
determine if the AG is the last AG and so has a runt size.  This
greatly simplifies some of the type validity checking we do and
substantially reduces the CPU overhead of type validity checking. It
also cuts over 1.2kB out of the binary size.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>

* tag 'xfs-perag-conv-5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs:
  xfs: make is_log_ag() a first class helper
  xfs: replace xfs_ag_block_count() with perag accesses
  xfs: Pre-calculate per-AG agino geometry
  xfs: Pre-calculate per-AG agbno geometry
  xfs: pass perag to xfs_alloc_read_agfl
  xfs: pass perag to xfs_alloc_put_freelist
  xfs: pass perag to xfs_alloc_get_freelist
  xfs: pass perag to xfs_read_agf
  xfs: pass perag to xfs_read_agi
  xfs: pass perag to xfs_alloc_read_agf()
  xfs: kill xfs_alloc_pagf_init()
  xfs: pass perag to xfs_ialloc_read_agi()
  xfs: kill xfs_ialloc_pagi_init()
  xfs: make last AG grow/shrink perag centric

fs/xfs/libxfs/xfs_ag.c

@@ -120,18 +120,18 @@ xfs_initialize_perag_data(
 
 	for (index = 0; index < agcount; index++) {
 		/*
-		 * read the agf, then the agi. This gets us
-		 * all the information we need and populates the
-		 * per-ag structures for us.
+		 * Read the AGF and AGI buffers to populate the per-ag
+		 * structures for us.
 		 */
-		error = xfs_alloc_pagf_init(mp, NULL, index, 0);
-		if (error)
+		pag = xfs_perag_get(mp, index);
+		error = xfs_alloc_read_agf(pag, NULL, 0, NULL);
+		if (!error)
+			error = xfs_ialloc_read_agi(pag, NULL, NULL);
+		if (error) {
+			xfs_perag_put(pag);
 			return error;
+		}
 
-		error = xfs_ialloc_pagi_init(mp, NULL, index);
-		if (error)
-			return error;
-		pag = xfs_perag_get(mp, index);
 		ifree += pag->pagi_freecount;
 		ialloc += pag->pagi_count;
 		bfree += pag->pagf_freeblks;
@@ -201,10 +201,70 @@ xfs_free_perag(
 	}
 }
 
+/* Find the size of the AG, in blocks. */
+static xfs_agblock_t
+__xfs_ag_block_count(
+	struct xfs_mount	*mp,
+	xfs_agnumber_t		agno,
+	xfs_agnumber_t		agcount,
+	xfs_rfsblock_t		dblocks)
+{
+	ASSERT(agno < agcount);
+
+	if (agno < agcount - 1)
+		return mp->m_sb.sb_agblocks;
+	return dblocks - (agno * mp->m_sb.sb_agblocks);
+}
+
+xfs_agblock_t
+xfs_ag_block_count(
+	struct xfs_mount	*mp,
+	xfs_agnumber_t		agno)
+{
+	return __xfs_ag_block_count(mp, agno, mp->m_sb.sb_agcount,
+			mp->m_sb.sb_dblocks);
+}
+
+/* Calculate the first and last possible inode number in an AG. */
+static void
+__xfs_agino_range(
+	struct xfs_mount	*mp,
+	xfs_agblock_t		eoag,
+	xfs_agino_t		*first,
+	xfs_agino_t		*last)
+{
+	xfs_agblock_t		bno;
+
+	/*
+	 * Calculate the first inode, which will be in the first
+	 * cluster-aligned block after the AGFL.
+	 */
+	bno = round_up(XFS_AGFL_BLOCK(mp) + 1, M_IGEO(mp)->cluster_align);
+	*first = XFS_AGB_TO_AGINO(mp, bno);
+
+	/*
+	 * Calculate the last inode, which will be at the end of the
+	 * last (aligned) cluster that can be allocated in the AG.
+	 */
+	bno = round_down(eoag, M_IGEO(mp)->cluster_align);
+	*last = XFS_AGB_TO_AGINO(mp, bno) - 1;
+}
+
+void
+xfs_agino_range(
+	struct xfs_mount	*mp,
+	xfs_agnumber_t		agno,
+	xfs_agino_t		*first,
+	xfs_agino_t		*last)
+{
+	return __xfs_agino_range(mp, xfs_ag_block_count(mp, agno), first, last);
+}
+
 int
 xfs_initialize_perag(
 	struct xfs_mount	*mp,
 	xfs_agnumber_t		agcount,
+	xfs_rfsblock_t		dblocks,
 	xfs_agnumber_t		*maxagi)
 {
 	struct xfs_perag	*pag;
@@ -270,6 +330,15 @@ xfs_initialize_perag(
 		/* first new pag is fully initialized */
 		if (first_initialised == NULLAGNUMBER)
 			first_initialised = index;
+
+		/*
+		 * Pre-calculated geometry
+		 */
+		pag->block_count = __xfs_ag_block_count(mp, index, agcount,
+				dblocks);
+		pag->min_block = XFS_AGFL_BLOCK(mp);
+		__xfs_agino_range(mp, pag->block_count, &pag->agino_min,
+				&pag->agino_max);
 	}
 
 	index = xfs_set_inode_alloc(mp, agcount);
@@ -321,12 +390,6 @@ xfs_get_aghdr_buf(
 	return 0;
 }
 
-static inline bool is_log_ag(struct xfs_mount *mp, struct aghdr_init_data *id)
-{
-	return mp->m_sb.sb_logstart > 0 &&
-	       id->agno == XFS_FSB_TO_AGNO(mp, mp->m_sb.sb_logstart);
-}
-
 /*
  * Generic btree root block init function
  */
@@ -352,7 +415,7 @@ xfs_freesp_init_recs(
 	arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
 	arec->ar_startblock = cpu_to_be32(mp->m_ag_prealloc_blocks);
 
-	if (is_log_ag(mp, id)) {
+	if (xfs_ag_contains_log(mp, id->agno)) {
 		struct xfs_alloc_rec	*nrec;
 		xfs_agblock_t		start = XFS_FSB_TO_AGBNO(mp,
 							mp->m_sb.sb_logstart);
@@ -479,7 +542,7 @@ xfs_rmaproot_init(
 	}
 
 	/* account for the log space */
-	if (is_log_ag(mp, id)) {
+	if (xfs_ag_contains_log(mp, id->agno)) {
 		rrec = XFS_RMAP_REC_ADDR(block,
 				be16_to_cpu(block->bb_numrecs) + 1);
 		rrec->rm_startblock = cpu_to_be32(
@@ -550,7 +613,7 @@ xfs_agfblock_init(
 		agf->agf_refcount_blocks = cpu_to_be32(1);
 	}
 
-	if (is_log_ag(mp, id)) {
+	if (xfs_ag_contains_log(mp, id->agno)) {
 		int64_t	logblocks = mp->m_sb.sb_logblocks;
 
 		be32_add_cpu(&agf->agf_freeblks, -logblocks);
@@ -761,11 +824,11 @@ xfs_ag_init_headers(
 
 int
 xfs_ag_shrink_space(
-	struct xfs_mount	*mp,
+	struct xfs_perag	*pag,
 	struct xfs_trans	**tpp,
-	xfs_agnumber_t		agno,
 	xfs_extlen_t		delta)
 {
+	struct xfs_mount	*mp = pag->pag_mount;
 	struct xfs_alloc_arg	args = {
 		.tp	= *tpp,
 		.mp	= mp,
@@ -782,14 +845,14 @@ xfs_ag_shrink_space(
 	xfs_agblock_t		aglen;
 	int			error, err2;
 
-	ASSERT(agno == mp->m_sb.sb_agcount - 1);
-	error = xfs_ialloc_read_agi(mp, *tpp, agno, &agibp);
+	ASSERT(pag->pag_agno == mp->m_sb.sb_agcount - 1);
+	error = xfs_ialloc_read_agi(pag, *tpp, &agibp);
 	if (error)
 		return error;
 
 	agi = agibp->b_addr;
 
-	error = xfs_alloc_read_agf(mp, *tpp, agno, 0, &agfbp);
+	error = xfs_alloc_read_agf(pag, *tpp, 0, &agfbp);
 	if (error)
 		return error;
 
@@ -801,13 +864,14 @@ xfs_ag_shrink_space(
 	if (delta >= aglen)
 		return -EINVAL;
 
-	args.fsbno = XFS_AGB_TO_FSB(mp, agno, aglen - delta);
+	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, agno, agibp, aglen - delta);
+	error = xfs_ialloc_check_shrink(*tpp, pag->pag_agno, agibp,
+			aglen - delta);
 	if (error)
 		return error;
 
@@ -815,7 +879,7 @@ xfs_ag_shrink_space(
 	 * Disable perag reservations so it doesn't cause the allocation request
 	 * to fail. We'll reestablish reservation before we return.
 	 */
-	error = xfs_ag_resv_free(agibp->b_pag);
+	error = xfs_ag_resv_free(pag);
 	if (error)
 		return error;
 
@@ -844,7 +908,7 @@ xfs_ag_shrink_space(
 	be32_add_cpu(&agi->agi_length, -delta);
 	be32_add_cpu(&agf->agf_length, -delta);
 
-	err2 = xfs_ag_resv_init(agibp->b_pag, *tpp);
+	err2 = xfs_ag_resv_init(pag, *tpp);
 	if (err2) {
 		be32_add_cpu(&agi->agi_length, delta);
 		be32_add_cpu(&agf->agf_length, delta);
@@ -868,8 +932,9 @@ xfs_ag_shrink_space(
 	xfs_ialloc_log_agi(*tpp, agibp, XFS_AGI_LENGTH);
 	xfs_alloc_log_agf(*tpp, agfbp, XFS_AGF_LENGTH);
 	return 0;
+
 resv_init_out:
-	err2 = xfs_ag_resv_init(agibp->b_pag, *tpp);
+	err2 = xfs_ag_resv_init(pag, *tpp);
 	if (!err2)
 		return error;
 resv_err:
@@ -883,9 +948,8 @@ xfs_ag_shrink_space(
  */
 int
 xfs_ag_extend_space(
-	struct xfs_mount	*mp,
+	struct xfs_perag	*pag,
 	struct xfs_trans	*tp,
-	struct aghdr_init_data	*id,
 	xfs_extlen_t		len)
 {
 	struct xfs_buf		*bp;
@@ -893,23 +957,20 @@ xfs_ag_extend_space(
 	struct xfs_agf		*agf;
 	int			error;
 
-	/*
-	 * Change the agi length.
-	 */
-	error = xfs_ialloc_read_agi(mp, tp, id->agno, &bp);
+	ASSERT(pag->pag_agno == pag->pag_mount->m_sb.sb_agcount - 1);
+
+	error = xfs_ialloc_read_agi(pag, tp, &bp);
 	if (error)
 		return error;
 
 	agi = bp->b_addr;
 	be32_add_cpu(&agi->agi_length, len);
-	ASSERT(id->agno == mp->m_sb.sb_agcount - 1 ||
-	       be32_to_cpu(agi->agi_length) == mp->m_sb.sb_agblocks);
 	xfs_ialloc_log_agi(tp, bp, XFS_AGI_LENGTH);
 
 	/*
 	 * Change agf length.
 	 */
-	error = xfs_alloc_read_agf(mp, tp, id->agno, 0, &bp);
+	error = xfs_alloc_read_agf(pag, tp, 0, &bp);
 	if (error)
 		return error;
 
@@ -924,49 +985,49 @@ xfs_ag_extend_space(
 	 * XFS_RMAP_OINFO_SKIP_UPDATE is used here to tell the rmap btree that
 	 * this doesn't actually exist in the rmap btree.
 	 */
-	error = xfs_rmap_free(tp, bp, bp->b_pag,
-				be32_to_cpu(agf->agf_length) - len,
+	error = xfs_rmap_free(tp, bp, pag, be32_to_cpu(agf->agf_length) - len,
 				len, &XFS_RMAP_OINFO_SKIP_UPDATE);
 	if (error)
 		return error;
 
-	return  xfs_free_extent(tp, XFS_AGB_TO_FSB(mp, id->agno,
+	error = xfs_free_extent(tp, XFS_AGB_TO_FSB(pag->pag_mount, pag->pag_agno,
 					be32_to_cpu(agf->agf_length) - len),
 				len, &XFS_RMAP_OINFO_SKIP_UPDATE,
 				XFS_AG_RESV_NONE);
+	if (error)
+		return error;
+
+	/* Update perag geometry */
+	pag->block_count = be32_to_cpu(agf->agf_length);
+	__xfs_agino_range(pag->pag_mount, pag->block_count, &pag->agino_min,
+				&pag->agino_max);
+	return 0;
 }
 
 /* Retrieve AG geometry. */
 int
 xfs_ag_get_geometry(
-	struct xfs_mount	*mp,
-	xfs_agnumber_t		agno,
+	struct xfs_perag	*pag,
 	struct xfs_ag_geometry	*ageo)
 {
 	struct xfs_buf		*agi_bp;
 	struct xfs_buf		*agf_bp;
 	struct xfs_agi		*agi;
 	struct xfs_agf		*agf;
-	struct xfs_perag	*pag;
 	unsigned int		freeblks;
 	int			error;
 
-	if (agno >= mp->m_sb.sb_agcount)
-		return -EINVAL;
-
 	/* Lock the AG headers. */
-	error = xfs_ialloc_read_agi(mp, NULL, agno, &agi_bp);
+	error = xfs_ialloc_read_agi(pag, NULL, &agi_bp);
 	if (error)
 		return error;
-	error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agf_bp);
+	error = xfs_alloc_read_agf(pag, NULL, 0, &agf_bp);
 	if (error)
 		goto out_agi;
 
-	pag = agi_bp->b_pag;
-
 	/* Fill out form. */
 	memset(ageo, 0, sizeof(*ageo));
-	ageo->ag_number = agno;
+	ageo->ag_number = pag->pag_agno;
 
 	agi = agi_bp->b_addr;
 	ageo->ag_icount = be32_to_cpu(agi->agi_count);

fs/xfs/libxfs/xfs_ag.h

@@ -67,6 +67,12 @@ struct xfs_perag {
 	/* for rcu-safe freeing */
 	struct rcu_head	rcu_head;
 
+	/* Precalculated geometry info */
+	xfs_agblock_t		block_count;
+	xfs_agblock_t		min_block;
+	xfs_agino_t		agino_min;
+	xfs_agino_t		agino_max;
+
 #ifdef __KERNEL__
 	/* -- kernel only structures below this line -- */
 
@@ -107,7 +113,7 @@ struct xfs_perag {
 };
 
 int xfs_initialize_perag(struct xfs_mount *mp, xfs_agnumber_t agcount,
-			xfs_agnumber_t *maxagi);
+			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);
 
@@ -116,6 +122,56 @@ 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);
 
+/*
+ * Per-ag geometry infomation and validation
+ */
+xfs_agblock_t xfs_ag_block_count(struct xfs_mount *mp, xfs_agnumber_t agno);
+void xfs_agino_range(struct xfs_mount *mp, xfs_agnumber_t agno,
+		xfs_agino_t *first, xfs_agino_t *last);
+
+static inline bool
+xfs_verify_agbno(struct xfs_perag *pag, xfs_agblock_t agbno)
+{
+	if (agbno >= pag->block_count)
+		return false;
+	if (agbno <= pag->min_block)
+		return false;
+	return true;
+}
+
+/*
+ * Verify that an AG inode number pointer neither points outside the AG
+ * nor points at static metadata.
+ */
+static inline bool
+xfs_verify_agino(struct xfs_perag *pag, xfs_agino_t agino)
+{
+	if (agino < pag->agino_min)
+		return false;
+	if (agino > pag->agino_max)
+		return false;
+	return true;
+}
+
+/*
+ * Verify that an AG inode number pointer neither points outside the AG
+ * nor points at static metadata, or is NULLAGINO.
+ */
+static inline bool
+xfs_verify_agino_or_null(struct xfs_perag *pag, xfs_agino_t agino)
+{
+	if (agino == NULLAGINO)
+		return true;
+	return xfs_verify_agino(pag, agino);
+}
+
+static inline bool
+xfs_ag_contains_log(struct xfs_mount *mp, xfs_agnumber_t agno)
+{
+	return mp->m_sb.sb_logstart > 0 &&
+	       agno == XFS_FSB_TO_AGNO(mp, mp->m_sb.sb_logstart);
+}
+
 /*
  * Perag iteration APIs
  */
@@ -168,11 +224,10 @@ struct aghdr_init_data {
 };
 
 int xfs_ag_init_headers(struct xfs_mount *mp, struct aghdr_init_data *id);
-int xfs_ag_shrink_space(struct xfs_mount *mp, struct xfs_trans **tpp,
-			xfs_agnumber_t agno, xfs_extlen_t delta);
-int xfs_ag_extend_space(struct xfs_mount *mp, struct xfs_trans *tp,
-			struct aghdr_init_data *id, xfs_extlen_t len);
-int xfs_ag_get_geometry(struct xfs_mount *mp, xfs_agnumber_t agno,
-			struct xfs_ag_geometry *ageo);
+int xfs_ag_shrink_space(struct xfs_perag *pag, struct xfs_trans **tpp,
+			xfs_extlen_t delta);
+int xfs_ag_extend_space(struct xfs_perag *pag, struct xfs_trans *tp,
+			xfs_extlen_t len);
+int xfs_ag_get_geometry(struct xfs_perag *pag, struct xfs_ag_geometry *ageo);
 
 #endif /* __LIBXFS_AG_H */

fs/xfs/libxfs/xfs_ag_resv.c

@@ -322,7 +322,7 @@ xfs_ag_resv_init(
 	 * address.
 	 */
 	if (has_resv) {
-		error2 = xfs_alloc_pagf_init(mp, tp, pag->pag_agno, 0);
+		error2 = xfs_alloc_read_agf(pag, tp, 0, NULL);
 		if (error2)
 			return error2;
 

fs/xfs/libxfs/xfs_alloc.c

@@ -248,7 +248,7 @@ xfs_alloc_get_rec(
 	int			*stat)	/* output: success/failure */
 {
 	struct xfs_mount	*mp = cur->bc_mp;
-	xfs_agnumber_t		agno = cur->bc_ag.pag->pag_agno;
+	struct xfs_perag	*pag = cur->bc_ag.pag;
 	union xfs_btree_rec	*rec;
 	int			error;
 
@@ -263,11 +263,11 @@ xfs_alloc_get_rec(
 		goto out_bad_rec;
 
 	/* check for valid extent range, including overflow */
-	if (!xfs_verify_agbno(mp, agno, *bno))
+	if (!xfs_verify_agbno(pag, *bno))
 		goto out_bad_rec;
 	if (*bno > *bno + *len)
 		goto out_bad_rec;
-	if (!xfs_verify_agbno(mp, agno, *bno + *len - 1))
+	if (!xfs_verify_agbno(pag, *bno + *len - 1))
 		goto out_bad_rec;
 
 	return 0;
@@ -275,7 +275,8 @@ xfs_alloc_get_rec(
 out_bad_rec:
 	xfs_warn(mp,
 		"%s Freespace BTree record corruption in AG %d detected!",
-		cur->bc_btnum == XFS_BTNUM_BNO ? "Block" : "Size", agno);
+		cur->bc_btnum == XFS_BTNUM_BNO ? "Block" : "Size",
+		pag->pag_agno);
 	xfs_warn(mp,
 		"start block 0x%x block count 0x%x", *bno, *len);
 	return -EFSCORRUPTED;
@@ -703,20 +704,19 @@ const struct xfs_buf_ops xfs_agfl_buf_ops = {
 /*
  * Read in the allocation group free block array.
  */
-int					/* error */
+int
 xfs_alloc_read_agfl(
-	xfs_mount_t	*mp,		/* mount point structure */
-	xfs_trans_t	*tp,		/* transaction pointer */
-	xfs_agnumber_t	agno,		/* allocation group number */
-	struct xfs_buf	**bpp)		/* buffer for the ag free block array */
+	struct xfs_perag	*pag,
+	struct xfs_trans	*tp,
+	struct xfs_buf		**bpp)
 {
-	struct xfs_buf	*bp;		/* return value */
+	struct xfs_mount	*mp = pag->pag_mount;
+	struct xfs_buf		*bp;
 	int			error;
 
-	ASSERT(agno != NULLAGNUMBER);
 	error = xfs_trans_read_buf(
 			mp, tp, mp->m_ddev_targp,
-			XFS_AG_DADDR(mp, agno, XFS_AGFL_DADDR(mp)),
+			XFS_AG_DADDR(mp, pag->pag_agno, XFS_AGFL_DADDR(mp)),
 			XFS_FSS_TO_BB(mp, 1), 0, &bp, &xfs_agfl_buf_ops);
 	if (error)
 		return error;
@@ -1075,7 +1075,8 @@ xfs_alloc_ag_vextent_small(
 	    be32_to_cpu(agf->agf_flcount) <= args->minleft)
 		goto out;
 
-	error = xfs_alloc_get_freelist(args->tp, args->agbp, &fbno, 0);
+	error = xfs_alloc_get_freelist(args->pag, args->tp, args->agbp,
+			&fbno, 0);
 	if (error)
 		goto error;
 	if (fbno == NULLAGBLOCK)
@@ -2609,7 +2610,7 @@ xfs_alloc_fix_freelist(
 	ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
 
 	if (!pag->pagf_init) {
-		error = xfs_alloc_read_agf(mp, tp, args->agno, flags, &agbp);
+		error = xfs_alloc_read_agf(pag, tp, flags, &agbp);
 		if (error) {
 			/* Couldn't lock the AGF so skip this AG. */
 			if (error == -EAGAIN)
@@ -2639,7 +2640,7 @@ xfs_alloc_fix_freelist(
 	 * Can fail if we're not blocking on locks, and it's held.
 	 */
 	if (!agbp) {
-		error = xfs_alloc_read_agf(mp, tp, args->agno, flags, &agbp);
+		error = xfs_alloc_read_agf(pag, tp, flags, &agbp);
 		if (error) {
 			/* Couldn't lock the AGF so skip this AG. */
 			if (error == -EAGAIN)
@@ -2697,7 +2698,7 @@ xfs_alloc_fix_freelist(
 	else
 		targs.oinfo = XFS_RMAP_OINFO_AG;
 	while (!(flags & XFS_ALLOC_FLAG_NOSHRINK) && pag->pagf_flcount > need) {
-		error = xfs_alloc_get_freelist(tp, agbp, &bno, 0);
+		error = xfs_alloc_get_freelist(pag, tp, agbp, &bno, 0);
 		if (error)
 			goto out_agbp_relse;
 
@@ -2712,7 +2713,7 @@ xfs_alloc_fix_freelist(
 	targs.alignment = targs.minlen = targs.prod = 1;
 	targs.type = XFS_ALLOCTYPE_THIS_AG;
 	targs.pag = pag;
-	error = xfs_alloc_read_agfl(mp, tp, targs.agno, &agflbp);
+	error = xfs_alloc_read_agfl(pag, tp, &agflbp);
 	if (error)
 		goto out_agbp_relse;
 
@@ -2741,7 +2742,7 @@ xfs_alloc_fix_freelist(
 		 * Put each allocated block on the list.
 		 */
 		for (bno = targs.agbno; bno < targs.agbno + targs.len; bno++) {
-			error = xfs_alloc_put_freelist(tp, agbp,
+			error = xfs_alloc_put_freelist(pag, tp, agbp,
 							agflbp, bno, 0);
 			if (error)
 				goto out_agflbp_relse;
@@ -2767,6 +2768,7 @@ xfs_alloc_fix_freelist(
  */
 int
 xfs_alloc_get_freelist(
+	struct xfs_perag	*pag,
 	struct xfs_trans	*tp,
 	struct xfs_buf		*agbp,
 	xfs_agblock_t		*bnop,
@@ -2779,7 +2781,6 @@ xfs_alloc_get_freelist(
 	int			error;
 	uint32_t		logflags;
 	struct xfs_mount	*mp = tp->t_mountp;
-	struct xfs_perag	*pag;
 
 	/*
 	 * Freelist is empty, give up.
@@ -2791,8 +2792,7 @@ xfs_alloc_get_freelist(
 	/*
 	 * Read the array of free blocks.
 	 */
-	error = xfs_alloc_read_agfl(mp, tp, be32_to_cpu(agf->agf_seqno),
-				    &agflbp);
+	error = xfs_alloc_read_agfl(pag, tp, &agflbp);
 	if (error)
 		return error;
 
@@ -2807,7 +2807,6 @@ xfs_alloc_get_freelist(
 	if (be32_to_cpu(agf->agf_flfirst) == xfs_agfl_size(mp))
 		agf->agf_flfirst = 0;
 
-	pag = agbp->b_pag;
 	ASSERT(!pag->pagf_agflreset);
 	be32_add_cpu(&agf->agf_flcount, -1);
 	pag->pagf_flcount--;
@@ -2867,30 +2866,12 @@ xfs_alloc_log_agf(
 	xfs_trans_log_buf(tp, bp, (uint)first, (uint)last);
 }
 
-/*
- * Interface for inode allocation to force the pag data to be initialized.
- */
-int					/* error */
-xfs_alloc_pagf_init(
-	xfs_mount_t		*mp,	/* file system mount structure */
-	xfs_trans_t		*tp,	/* transaction pointer */
-	xfs_agnumber_t		agno,	/* allocation group number */
-	int			flags)	/* XFS_ALLOC_FLAGS_... */
-{
-	struct xfs_buf		*bp;
-	int			error;
-
-	error = xfs_alloc_read_agf(mp, tp, agno, flags, &bp);
-	if (!error)
-		xfs_trans_brelse(tp, bp);
-	return error;
-}
-
 /*
  * Put the block on the freelist for the allocation group.
  */
 int
 xfs_alloc_put_freelist(
+	struct xfs_perag	*pag,
 	struct xfs_trans	*tp,
 	struct xfs_buf		*agbp,
 	struct xfs_buf		*agflbp,
@@ -2899,21 +2880,22 @@ xfs_alloc_put_freelist(
 {
 	struct xfs_mount	*mp = tp->t_mountp;
 	struct xfs_agf		*agf = agbp->b_addr;
-	struct xfs_perag	*pag;
 	__be32			*blockp;
 	int			error;
 	uint32_t		logflags;
 	__be32			*agfl_bno;
 	int			startoff;
 
-	if (!agflbp && (error = xfs_alloc_read_agfl(mp, tp,
-			be32_to_cpu(agf->agf_seqno), &agflbp)))
+	if (!agflbp) {
+		error = xfs_alloc_read_agfl(pag, tp, &agflbp);
+		if (error)
 			return error;
+	}
+
 	be32_add_cpu(&agf->agf_fllast, 1);
 	if (be32_to_cpu(agf->agf_fllast) == xfs_agfl_size(mp))
 		agf->agf_fllast = 0;
 
-	pag = agbp->b_pag;
 	ASSERT(!pag->pagf_agflreset);
 	be32_add_cpu(&agf->agf_flcount, 1);
 	pag->pagf_flcount++;
@@ -3070,61 +3052,57 @@ const struct xfs_buf_ops xfs_agf_buf_ops = {
 /*
  * Read in the allocation group header (free/alloc section).
  */
-int					/* error */
+int
 xfs_read_agf(
-	struct xfs_mount	*mp,	/* mount point structure */
-	struct xfs_trans	*tp,	/* transaction pointer */
-	xfs_agnumber_t		agno,	/* allocation group number */
-	int			flags,	/* XFS_BUF_ */
-	struct xfs_buf		**bpp)	/* buffer for the ag freelist header */
+	struct xfs_perag	*pag,
+	struct xfs_trans	*tp,
+	int			flags,
+	struct xfs_buf		**agfbpp)
 {
+	struct xfs_mount	*mp = pag->pag_mount;
 	int			error;
 
-	trace_xfs_read_agf(mp, agno);
+	trace_xfs_read_agf(pag->pag_mount, pag->pag_agno);
 
-	ASSERT(agno != NULLAGNUMBER);
 	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
-			XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)),
-			XFS_FSS_TO_BB(mp, 1), flags, bpp, &xfs_agf_buf_ops);
+			XFS_AG_DADDR(mp, pag->pag_agno, XFS_AGF_DADDR(mp)),
+			XFS_FSS_TO_BB(mp, 1), flags, agfbpp, &xfs_agf_buf_ops);
 	if (error)
 		return error;
 
-	ASSERT(!(*bpp)->b_error);
-	xfs_buf_set_ref(*bpp, XFS_AGF_REF);
+	xfs_buf_set_ref(*agfbpp, XFS_AGF_REF);
 	return 0;
 }
 
 /*
- * Read in the allocation group header (free/alloc section).
+ * Read in the allocation group header (free/alloc section) and initialise the
+ * perag structure if necessary. If the caller provides @agfbpp, then return the
+ * locked buffer to the caller, otherwise free it.
  */
-int					/* error */
+int
 xfs_alloc_read_agf(
-	struct xfs_mount	*mp,	/* mount point structure */
-	struct xfs_trans	*tp,	/* transaction pointer */
-	xfs_agnumber_t		agno,	/* allocation group number */
-	int			flags,	/* XFS_ALLOC_FLAG_... */
-	struct xfs_buf		**bpp)	/* buffer for the ag freelist header */
+	struct xfs_perag	*pag,
+	struct xfs_trans	*tp,
+	int			flags,
+	struct xfs_buf		**agfbpp)
 {
-	struct xfs_agf		*agf;		/* ag freelist header */
-	struct xfs_perag	*pag;		/* per allocation group data */
+	struct xfs_buf		*agfbp;
+	struct xfs_agf		*agf;
 	int			error;
 	int			allocbt_blks;
 
-	trace_xfs_alloc_read_agf(mp, agno);
+	trace_xfs_alloc_read_agf(pag->pag_mount, pag->pag_agno);
 
 	/* We don't support trylock when freeing. */
 	ASSERT((flags & (XFS_ALLOC_FLAG_FREEING | XFS_ALLOC_FLAG_TRYLOCK)) !=
 			(XFS_ALLOC_FLAG_FREEING | XFS_ALLOC_FLAG_TRYLOCK));
-	ASSERT(agno != NULLAGNUMBER);
-	error = xfs_read_agf(mp, tp, agno,
+	error = xfs_read_agf(pag, tp,
 			(flags & XFS_ALLOC_FLAG_TRYLOCK) ? XBF_TRYLOCK : 0,
-			bpp);
+			&agfbp);
 	if (error)
 		return error;
-	ASSERT(!(*bpp)->b_error);
 
-	agf = (*bpp)->b_addr;
-	pag = (*bpp)->b_pag;
+	agf = agfbp->b_addr;
 	if (!pag->pagf_init) {
 		pag->pagf_freeblks = be32_to_cpu(agf->agf_freeblks);
 		pag->pagf_btreeblks = be32_to_cpu(agf->agf_btreeblks);
@@ -3138,7 +3116,7 @@ xfs_alloc_read_agf(
 			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(mp, agf);
+		pag->pagf_agflreset = xfs_agfl_needs_reset(pag->pag_mount, agf);
 
 		/*
 		 * Update the in-core allocbt counter. Filter out the rmapbt
@@ -3148,13 +3126,14 @@ xfs_alloc_read_agf(
 		 * counter only tracks non-root blocks.
 		 */
 		allocbt_blks = pag->pagf_btreeblks;
-		if (xfs_has_rmapbt(mp))
+		if (xfs_has_rmapbt(pag->pag_mount))
 			allocbt_blks -= be32_to_cpu(agf->agf_rmap_blocks) - 1;
 		if (allocbt_blks > 0)
-			atomic64_add(allocbt_blks, &mp->m_allocbt_blks);
+			atomic64_add(allocbt_blks,
+					&pag->pag_mount->m_allocbt_blks);
 	}
 #ifdef DEBUG
-	else if (!xfs_is_shutdown(mp)) {
+	else if (!xfs_is_shutdown(pag->pag_mount)) {
 		ASSERT(pag->pagf_freeblks == be32_to_cpu(agf->agf_freeblks));
 		ASSERT(pag->pagf_btreeblks == be32_to_cpu(agf->agf_btreeblks));
 		ASSERT(pag->pagf_flcount == be32_to_cpu(agf->agf_flcount));
@@ -3165,6 +3144,10 @@ xfs_alloc_read_agf(
 		       be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]));
 	}
 #endif
+	if (agfbpp)
+		*agfbpp = agfbp;
+	else
+		xfs_trans_brelse(tp, agfbp);
 	return 0;
 }
 

fs/xfs/libxfs/xfs_alloc.h

@@ -95,6 +95,11 @@ xfs_extlen_t xfs_alloc_longest_free_extent(struct xfs_perag *pag,
 		xfs_extlen_t need, xfs_extlen_t reserved);
 unsigned int xfs_alloc_min_freelist(struct xfs_mount *mp,
 		struct xfs_perag *pag);
+int xfs_alloc_get_freelist(struct xfs_perag *pag, struct xfs_trans *tp,
+		struct xfs_buf *agfbp, xfs_agblock_t *bnop, int	 btreeblk);
+int xfs_alloc_put_freelist(struct xfs_perag *pag, struct xfs_trans *tp,
+		struct xfs_buf *agfbp, struct xfs_buf *agflbp,
+		xfs_agblock_t bno, int btreeblk);
 
 /*
  * Compute and fill in value of m_alloc_maxlevels.
@@ -103,17 +108,6 @@ void
 xfs_alloc_compute_maxlevels(
 	struct xfs_mount	*mp);	/* file system mount structure */
 
-/*
- * Get a block from the freelist.
- * Returns with the buffer for the block gotten.
- */
-int				/* error */
-xfs_alloc_get_freelist(
-	struct xfs_trans *tp,	/* transaction pointer */
-	struct xfs_buf	*agbp,	/* buffer containing the agf structure */
-	xfs_agblock_t	*bnop,	/* block address retrieved from freelist */
-	int		btreeblk); /* destination is a AGF btree */
-
 /*
  * Log the given fields from the agf structure.
  */
@@ -123,38 +117,6 @@ xfs_alloc_log_agf(
 	struct xfs_buf	*bp,	/* buffer for a.g. freelist header */
 	uint32_t	fields);/* mask of fields to be logged (XFS_AGF_...) */
 
-/*
- * Interface for inode allocation to force the pag data to be initialized.
- */
-int				/* error */
-xfs_alloc_pagf_init(
-	struct xfs_mount *mp,	/* file system mount structure */
-	struct xfs_trans *tp,	/* transaction pointer */
-	xfs_agnumber_t	agno,	/* allocation group number */
-	int		flags);	/* XFS_ALLOC_FLAGS_... */
-
-/*
- * Put the block on the freelist for the allocation group.
- */
-int				/* error */
-xfs_alloc_put_freelist(
-	struct xfs_trans *tp,	/* transaction pointer */
-	struct xfs_buf	*agbp,	/* buffer for a.g. freelist header */
-	struct xfs_buf	*agflbp,/* buffer for a.g. free block array */
-	xfs_agblock_t	bno,	/* block being freed */
-	int		btreeblk); /* owner was a AGF btree */
-
-/*
- * Read in the allocation group header (free/alloc section).
- */
-int					/* error  */
-xfs_alloc_read_agf(
-	struct xfs_mount *mp,		/* mount point structure */
-	struct xfs_trans *tp,		/* transaction pointer */
-	xfs_agnumber_t	agno,		/* allocation group number */
-	int		flags,		/* XFS_ALLOC_FLAG_... */
-	struct xfs_buf	**bpp);		/* buffer for the ag freelist header */
-
 /*
  * Allocate an extent (variable-size).
  */
@@ -206,10 +168,12 @@ xfs_alloc_get_rec(
 	xfs_extlen_t		*len,	/* output: length of extent */
 	int			*stat);	/* output: success/failure */
 
-int xfs_read_agf(struct xfs_mount *mp, struct xfs_trans *tp,
-			xfs_agnumber_t agno, int flags, struct xfs_buf **bpp);
-int xfs_alloc_read_agfl(struct xfs_mount *mp, struct xfs_trans *tp,
-			xfs_agnumber_t agno, struct xfs_buf **bpp);
+int xfs_read_agf(struct xfs_perag *pag, struct xfs_trans *tp, int flags,
+		struct xfs_buf **agfbpp);
+int xfs_alloc_read_agf(struct xfs_perag *pag, struct xfs_trans *tp, int flags,
+		struct xfs_buf **agfbpp);
+int xfs_alloc_read_agfl(struct xfs_perag *pag, struct xfs_trans *tp,
+		struct xfs_buf **bpp);
 int xfs_free_agfl_block(struct xfs_trans *, xfs_agnumber_t, xfs_agblock_t,
 			struct xfs_buf *, struct xfs_owner_info *);
 int xfs_alloc_fix_freelist(struct xfs_alloc_arg *args, int flags);

fs/xfs/libxfs/xfs_alloc_btree.c

@@ -60,8 +60,8 @@ xfs_allocbt_alloc_block(
 	xfs_agblock_t		bno;
 
 	/* Allocate the new block from the freelist. If we can't, give up.  */
-	error = xfs_alloc_get_freelist(cur->bc_tp, cur->bc_ag.agbp,
-				       &bno, 1);
+	error = xfs_alloc_get_freelist(cur->bc_ag.pag, cur->bc_tp,
+			cur->bc_ag.agbp, &bno, 1);
 	if (error)
 		return error;
 
@@ -71,7 +71,7 @@ xfs_allocbt_alloc_block(
 	}
 
 	atomic64_inc(&cur->bc_mp->m_allocbt_blks);
-	xfs_extent_busy_reuse(cur->bc_mp, cur->bc_ag.agbp->b_pag, bno, 1, false);
+	xfs_extent_busy_reuse(cur->bc_mp, cur->bc_ag.pag, bno, 1, false);
 
 	new->s = cpu_to_be32(bno);
 
@@ -89,7 +89,8 @@ xfs_allocbt_free_block(
 	int			error;
 
 	bno = xfs_daddr_to_agbno(cur->bc_mp, xfs_buf_daddr(bp));
-	error = xfs_alloc_put_freelist(cur->bc_tp, agbp, NULL, bno, 1);
+	error = xfs_alloc_put_freelist(cur->bc_ag.pag, cur->bc_tp, agbp, NULL,
+			bno, 1);
 	if (error)
 		return error;
 

fs/xfs/libxfs/xfs_bmap.c

@@ -3185,7 +3185,8 @@ xfs_bmap_longest_free_extent(
 
 	pag = xfs_perag_get(mp, ag);
 	if (!pag->pagf_init) {
-		error = xfs_alloc_pagf_init(mp, tp, ag, XFS_ALLOC_FLAG_TRYLOCK);
+		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) {

fs/xfs/libxfs/xfs_btree.c

@@ -91,10 +91,9 @@ xfs_btree_check_lblock_siblings(
 
 static inline xfs_failaddr_t
 xfs_btree_check_sblock_siblings(
-	struct xfs_mount	*mp,
+	struct xfs_perag	*pag,
 	struct xfs_btree_cur	*cur,
 	int			level,
-	xfs_agnumber_t		agno,
 	xfs_agblock_t		agbno,
 	__be32			dsibling)
 {
@@ -110,7 +109,7 @@ xfs_btree_check_sblock_siblings(
 		if (!xfs_btree_check_sptr(cur, sibling, level + 1))
 			return __this_address;
 	} else {
-		if (!xfs_verify_agbno(mp, agno, sibling))
+		if (!xfs_verify_agbno(pag, sibling))
 			return __this_address;
 	}
 	return NULL;
@@ -195,11 +194,11 @@ __xfs_btree_check_sblock(
 	struct xfs_buf		*bp)
 {
 	struct xfs_mount	*mp = cur->bc_mp;
+	struct xfs_perag	*pag = cur->bc_ag.pag;
 	xfs_btnum_t		btnum = cur->bc_btnum;
 	int			crc = xfs_has_crc(mp);
 	xfs_failaddr_t		fa;
 	xfs_agblock_t		agbno = NULLAGBLOCK;
-	xfs_agnumber_t		agno = NULLAGNUMBER;
 
 	if (crc) {
 		if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid))
@@ -217,16 +216,14 @@ __xfs_btree_check_sblock(
 	    cur->bc_ops->get_maxrecs(cur, level))
 		return __this_address;
 
-	if (bp) {
+	if (bp)
 		agbno = xfs_daddr_to_agbno(mp, xfs_buf_daddr(bp));
-		agno = xfs_daddr_to_agno(mp, xfs_buf_daddr(bp));
-	}
 
-	fa = xfs_btree_check_sblock_siblings(mp, cur, level, agno, agbno,
+	fa = xfs_btree_check_sblock_siblings(pag, cur, level, agbno,
 			block->bb_u.s.bb_leftsib);
 	if (!fa)
-		fa = xfs_btree_check_sblock_siblings(mp, cur, level, agno,
-				 agbno, block->bb_u.s.bb_rightsib);
+		fa = xfs_btree_check_sblock_siblings(pag, cur, level, agbno,
+				block->bb_u.s.bb_rightsib);
 	return fa;
 }
 
@@ -288,7 +285,7 @@ xfs_btree_check_sptr(
 {
 	if (level <= 0)
 		return false;
-	return xfs_verify_agbno(cur->bc_mp, cur->bc_ag.pag->pag_agno, agbno);
+	return xfs_verify_agbno(cur->bc_ag.pag, agbno);
 }
 
 /*
@@ -4595,7 +4592,6 @@ xfs_btree_sblock_verify(
 {
 	struct xfs_mount	*mp = bp->b_mount;
 	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
-	xfs_agnumber_t		agno;
 	xfs_agblock_t		agbno;
 	xfs_failaddr_t		fa;
 
@@ -4604,12 +4600,11 @@ xfs_btree_sblock_verify(
 		return __this_address;
 
 	/* sibling pointer verification */
-	agno = xfs_daddr_to_agno(mp, xfs_buf_daddr(bp));
 	agbno = xfs_daddr_to_agbno(mp, xfs_buf_daddr(bp));
-	fa = xfs_btree_check_sblock_siblings(mp, NULL, -1, agno, agbno,
+	fa = xfs_btree_check_sblock_siblings(bp->b_pag, NULL, -1, agbno,
 			block->bb_u.s.bb_leftsib);
 	if (!fa)
-		fa = xfs_btree_check_sblock_siblings(mp, NULL, -1, agno, agbno,
+		fa = xfs_btree_check_sblock_siblings(bp->b_pag, NULL, -1, agbno,
 				block->bb_u.s.bb_rightsib);
 	return fa;
 }

fs/xfs/libxfs/xfs_ialloc.c

@@ -105,7 +105,6 @@ xfs_inobt_get_rec(
 	int				*stat)
 {
 	struct xfs_mount		*mp = cur->bc_mp;
-	xfs_agnumber_t			agno = cur->bc_ag.pag->pag_agno;
 	union xfs_btree_rec		*rec;
 	int				error;
 	uint64_t			realfree;
@@ -116,7 +115,7 @@ xfs_inobt_get_rec(
 
 	xfs_inobt_btrec_to_irec(mp, rec, irec);
 
-	if (!xfs_verify_agino(mp, agno, irec->ir_startino))
+	if (!xfs_verify_agino(cur->bc_ag.pag, irec->ir_startino))
 		goto out_bad_rec;
 	if (irec->ir_count < XFS_INODES_PER_HOLEMASK_BIT ||
 	    irec->ir_count > XFS_INODES_PER_CHUNK)
@@ -137,7 +136,8 @@ xfs_inobt_get_rec(
 out_bad_rec:
 	xfs_warn(mp,
 		"%s Inode BTree record corruption in AG %d detected!",
-		cur->bc_btnum == XFS_BTNUM_INO ? "Used" : "Free", agno);
+		cur->bc_btnum == XFS_BTNUM_INO ? "Used" : "Free",
+		cur->bc_ag.pag->pag_agno);
 	xfs_warn(mp,
 "start inode 0x%x, count 0x%x, free 0x%x freemask 0x%llx, holemask 0x%x",
 		irec->ir_startino, irec->ir_count, irec->ir_freecount,
@@ -1610,7 +1610,7 @@ xfs_dialloc_good_ag(
 		return false;
 
 	if (!pag->pagi_init) {
-		error = xfs_ialloc_pagi_init(mp, tp, pag->pag_agno);
+		error = xfs_ialloc_read_agi(pag, tp, NULL);
 		if (error)
 			return false;
 	}
@@ -1621,7 +1621,7 @@ xfs_dialloc_good_ag(
 		return false;
 
 	if (!pag->pagf_init) {
-		error = xfs_alloc_pagf_init(mp, tp, pag->pag_agno, flags);
+		error = xfs_alloc_read_agf(pag, tp, flags, NULL);
 		if (error)
 			return false;
 	}
@@ -1679,7 +1679,7 @@ xfs_dialloc_try_ag(
 	 * Then read in the AGI buffer and recheck with the AGI buffer
 	 * lock held.
 	 */
-	error = xfs_ialloc_read_agi(pag->pag_mount, *tpp, pag->pag_agno, &agbp);
+	error = xfs_ialloc_read_agi(pag, *tpp, &agbp);
 	if (error)
 		return error;
 
@@ -2169,7 +2169,7 @@ xfs_difree(
 	/*
 	 * Get the allocation group header.
 	 */
-	error = xfs_ialloc_read_agi(mp, tp, pag->pag_agno, &agbp);
+	error = xfs_ialloc_read_agi(pag, tp, &agbp);
 	if (error) {
 		xfs_warn(mp, "%s: xfs_ialloc_read_agi() returned error %d.",
 			__func__, error);
@@ -2215,7 +2215,7 @@ xfs_imap_lookup(
 	int			error;
 	int			i;
 
-	error = xfs_ialloc_read_agi(mp, tp, pag->pag_agno, &agbp);
+	error = xfs_ialloc_read_agi(pag, tp, &agbp);
 	if (error) {
 		xfs_alert(mp,
 			"%s: xfs_ialloc_read_agi() returned error %d, agno %d",
@@ -2571,47 +2571,48 @@ const struct xfs_buf_ops xfs_agi_buf_ops = {
  */
 int
 xfs_read_agi(
-	struct xfs_mount	*mp,	/* file system mount structure */
-	struct xfs_trans	*tp,	/* transaction pointer */
-	xfs_agnumber_t		agno,	/* allocation group number */
-	struct xfs_buf		**bpp)	/* allocation group hdr buf */
+	struct xfs_perag	*pag,
+	struct xfs_trans	*tp,
+	struct xfs_buf		**agibpp)
 {
+	struct xfs_mount	*mp = pag->pag_mount;
 	int			error;
 
-	trace_xfs_read_agi(mp, agno);
+	trace_xfs_read_agi(pag->pag_mount, pag->pag_agno);
 
-	ASSERT(agno != NULLAGNUMBER);
 	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
-			XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
-			XFS_FSS_TO_BB(mp, 1), 0, bpp, &xfs_agi_buf_ops);
+			XFS_AG_DADDR(mp, pag->pag_agno, XFS_AGI_DADDR(mp)),
+			XFS_FSS_TO_BB(mp, 1), 0, agibpp, &xfs_agi_buf_ops);
 	if (error)
 		return error;
 	if (tp)
-		xfs_trans_buf_set_type(tp, *bpp, XFS_BLFT_AGI_BUF);
+		xfs_trans_buf_set_type(tp, *agibpp, XFS_BLFT_AGI_BUF);
 
-	xfs_buf_set_ref(*bpp, XFS_AGI_REF);
+	xfs_buf_set_ref(*agibpp, XFS_AGI_REF);
 	return 0;
 }
 
+/*
+ * Read in the agi and initialise the per-ag data. If the caller supplies a
+ * @agibpp, return the locked AGI buffer to them, otherwise release it.
+ */
 int
 xfs_ialloc_read_agi(
-	struct xfs_mount	*mp,	/* file system mount structure */
-	struct xfs_trans	*tp,	/* transaction pointer */
-	xfs_agnumber_t		agno,	/* allocation group number */
-	struct xfs_buf		**bpp)	/* allocation group hdr buf */
+	struct xfs_perag	*pag,
+	struct xfs_trans	*tp,
+	struct xfs_buf		**agibpp)
 {
-	struct xfs_agi		*agi;	/* allocation group header */
-	struct xfs_perag	*pag;	/* per allocation group data */
+	struct xfs_buf		*agibp;
+	struct xfs_agi		*agi;
 	int			error;
 
-	trace_xfs_ialloc_read_agi(mp, agno);
+	trace_xfs_ialloc_read_agi(pag->pag_mount, pag->pag_agno);
 
-	error = xfs_read_agi(mp, tp, agno, bpp);
+	error = xfs_read_agi(pag, tp, &agibp);
 	if (error)
 		return error;
 
-	agi = (*bpp)->b_addr;
-	pag = (*bpp)->b_pag;
+	agi = agibp->b_addr;
 	if (!pag->pagi_init) {
 		pag->pagi_freecount = be32_to_cpu(agi->agi_freecount);
 		pag->pagi_count = be32_to_cpu(agi->agi_count);
@@ -2623,27 +2624,11 @@ xfs_ialloc_read_agi(
 	 * we are in the middle of a forced shutdown.
 	 */
 	ASSERT(pag->pagi_freecount == be32_to_cpu(agi->agi_freecount) ||
-		xfs_is_shutdown(mp));
-	return 0;
-}
-
-/*
- * Read in the agi to initialise the per-ag data in the mount structure
- */
-int
-xfs_ialloc_pagi_init(
-	xfs_mount_t	*mp,		/* file system mount structure */
-	xfs_trans_t	*tp,		/* transaction pointer */
-	xfs_agnumber_t	agno)		/* allocation group number */
-{
-	struct xfs_buf	*bp = NULL;
-	int		error;
-
-	error = xfs_ialloc_read_agi(mp, tp, agno, &bp);
-	if (error)
-		return error;
-	if (bp)
-		xfs_trans_brelse(tp, bp);
+		xfs_is_shutdown(pag->pag_mount));
+	if (agibpp)
+		*agibpp = agibp;
+	else
+		xfs_trans_brelse(tp, agibp);
 	return 0;
 }
 
@@ -2912,8 +2897,7 @@ xfs_ialloc_calc_rootino(
 	 * allocation group, or very odd geometries created by old mkfs
 	 * versions on very small filesystems.
 	 */
-	if (mp->m_sb.sb_logstart &&
-	    XFS_FSB_TO_AGNO(mp, mp->m_sb.sb_logstart) == 0)
+	if (xfs_ag_contains_log(mp, 0))
 		 first_bno += mp->m_sb.sb_logblocks;
 
 	/*

fs/xfs/libxfs/xfs_ialloc.h

@@ -62,25 +62,10 @@ xfs_ialloc_log_agi(
 	struct xfs_buf	*bp,		/* allocation group header buffer */
 	uint32_t	fields);	/* bitmask of fields to log */
 
-/*
- * Read in the allocation group header (inode allocation section)
- */
-int					/* error */
-xfs_ialloc_read_agi(
-	struct xfs_mount *mp,		/* file system mount structure */
-	struct xfs_trans *tp,		/* transaction pointer */
-	xfs_agnumber_t	agno,		/* allocation group number */
-	struct xfs_buf	**bpp);		/* allocation group hdr buf */
-
-/*
- * Read in the allocation group header to initialise the per-ag data
- * in the mount structure
- */
-int
-xfs_ialloc_pagi_init(
-	struct xfs_mount *mp,		/* file system mount structure */
-	struct xfs_trans *tp,		/* transaction pointer */
-        xfs_agnumber_t  agno);		/* allocation group number */
+int xfs_read_agi(struct xfs_perag *pag, struct xfs_trans *tp,
+		struct xfs_buf **agibpp);
+int xfs_ialloc_read_agi(struct xfs_perag *pag, struct xfs_trans *tp,
+		struct xfs_buf **agibpp);
 
 /*
  * Lookup a record by ino in the btree given by cur.
@@ -102,8 +87,6 @@ int xfs_ialloc_inode_init(struct xfs_mount *mp, struct xfs_trans *tp,
 			  xfs_agnumber_t agno, xfs_agblock_t agbno,
 			  xfs_agblock_t length, unsigned int gen);
 
-int xfs_read_agi(struct xfs_mount *mp, struct xfs_trans *tp,
-		xfs_agnumber_t agno, struct xfs_buf **bpp);
 
 union xfs_btree_rec;
 void xfs_inobt_btrec_to_irec(struct xfs_mount *mp,

fs/xfs/libxfs/xfs_ialloc_btree.c

@@ -683,10 +683,10 @@ xfs_inobt_rec_check_count(
 
 static xfs_extlen_t
 xfs_inobt_max_size(
-	struct xfs_mount	*mp,
-	xfs_agnumber_t		agno)
+	struct xfs_perag	*pag)
 {
-	xfs_agblock_t		agblocks = xfs_ag_block_count(mp, agno);
+	struct xfs_mount	*mp = pag->pag_mount;
+	xfs_agblock_t		agblocks = pag->block_count;
 
 	/* Bail out if we're uninitialized, which can happen in mkfs. */
 	if (M_IGEO(mp)->inobt_mxr[0] == 0)
@@ -697,8 +697,7 @@ xfs_inobt_max_size(
 	 * never be available for the kinds of things that would require btree
 	 * expansion.  We therefore can pretend the space isn't there.
 	 */
-	if (mp->m_sb.sb_logstart &&
-	    XFS_FSB_TO_AGNO(mp, mp->m_sb.sb_logstart) == agno)
+	if (xfs_ag_contains_log(mp, pag->pag_agno))
 		agblocks -= mp->m_sb.sb_logblocks;
 
 	return xfs_btree_calc_size(M_IGEO(mp)->inobt_mnr,
@@ -722,7 +721,7 @@ xfs_inobt_cur(
 	ASSERT(*agi_bpp == NULL);
 	ASSERT(*curpp == NULL);
 
-	error = xfs_ialloc_read_agi(mp, tp, pag->pag_agno, agi_bpp);
+	error = xfs_ialloc_read_agi(pag, tp, agi_bpp);
 	if (error)
 		return error;
 
@@ -757,16 +756,15 @@ xfs_inobt_count_blocks(
 /* Read finobt block count from AGI header. */
 static int
 xfs_finobt_read_blocks(
-	struct xfs_mount	*mp,
-	struct xfs_trans	*tp,
 	struct xfs_perag	*pag,
+	struct xfs_trans	*tp,
 	xfs_extlen_t		*tree_blocks)
 {
 	struct xfs_buf		*agbp;
 	struct xfs_agi		*agi;
 	int			error;
 
-	error = xfs_ialloc_read_agi(mp, tp, pag->pag_agno, &agbp);
+	error = xfs_ialloc_read_agi(pag, tp, &agbp);
 	if (error)
 		return error;
 
@@ -794,14 +792,14 @@ xfs_finobt_calc_reserves(
 		return 0;
 
 	if (xfs_has_inobtcounts(mp))
-		error = xfs_finobt_read_blocks(mp, tp, pag, &tree_len);
+		error = xfs_finobt_read_blocks(pag, tp, &tree_len);
 	else
 		error = xfs_inobt_count_blocks(mp, tp, pag, XFS_BTNUM_FINO,
 				&tree_len);
 	if (error)
 		return error;
 
-	*ask += xfs_inobt_max_size(mp, pag->pag_agno);
+	*ask += xfs_inobt_max_size(pag);
 	*used += tree_len;
 	return 0;
 }

fs/xfs/libxfs/xfs_inode_buf.c

@@ -10,6 +10,7 @@
 #include "xfs_log_format.h"
 #include "xfs_trans_resv.h"
 #include "xfs_mount.h"
+#include "xfs_ag.h"
 #include "xfs_inode.h"
 #include "xfs_errortag.h"
 #include "xfs_error.h"
@@ -41,14 +42,12 @@ xfs_inode_buf_verify(
 	bool		readahead)
 {
 	struct xfs_mount *mp = bp->b_mount;
-	xfs_agnumber_t	agno;
 	int		i;
 	int		ni;
 
 	/*
 	 * Validate the magic number and version of every inode in the buffer
 	 */
-	agno = xfs_daddr_to_agno(mp, xfs_buf_daddr(bp));
 	ni = XFS_BB_TO_FSB(mp, bp->b_length) * mp->m_sb.sb_inopblock;
 	for (i = 0; i < ni; i++) {
 		struct xfs_dinode	*dip;
@@ -59,7 +58,7 @@ xfs_inode_buf_verify(
 		unlinked_ino = be32_to_cpu(dip->di_next_unlinked);
 		di_ok = xfs_verify_magic16(bp, dip->di_magic) &&
 			xfs_dinode_good_version(mp, dip->di_version) &&
-			xfs_verify_agino_or_null(mp, agno, unlinked_ino);
+			xfs_verify_agino_or_null(bp->b_pag, unlinked_ino);
 		if (unlikely(XFS_TEST_ERROR(!di_ok, mp,
 						XFS_ERRTAG_ITOBP_INOTOBP))) {
 			if (readahead) {

fs/xfs/libxfs/xfs_refcount.c

@@ -111,7 +111,7 @@ xfs_refcount_get_rec(
 	int				*stat)
 {
 	struct xfs_mount		*mp = cur->bc_mp;
-	xfs_agnumber_t			agno = cur->bc_ag.pag->pag_agno;
+	struct xfs_perag		*pag = cur->bc_ag.pag;
 	union xfs_btree_rec		*rec;
 	int				error;
 	xfs_agblock_t			realstart;
@@ -121,8 +121,6 @@ xfs_refcount_get_rec(
 		return error;
 
 	xfs_refcount_btrec_to_irec(rec, irec);
-
-	agno = cur->bc_ag.pag->pag_agno;
 	if (irec->rc_blockcount == 0 || irec->rc_blockcount > MAXREFCEXTLEN)
 		goto out_bad_rec;
 
@@ -137,22 +135,23 @@ xfs_refcount_get_rec(
 	}
 
 	/* check for valid extent range, including overflow */
-	if (!xfs_verify_agbno(mp, agno, realstart))
+	if (!xfs_verify_agbno(pag, realstart))
 		goto out_bad_rec;
 	if (realstart > realstart + irec->rc_blockcount)
 		goto out_bad_rec;
-	if (!xfs_verify_agbno(mp, agno, realstart + irec->rc_blockcount - 1))
+	if (!xfs_verify_agbno(pag, realstart + irec->rc_blockcount - 1))
 		goto out_bad_rec;
 
 	if (irec->rc_refcount == 0 || irec->rc_refcount > MAXREFCOUNT)
 		goto out_bad_rec;
 
-	trace_xfs_refcount_get(cur->bc_mp, cur->bc_ag.pag->pag_agno, irec);
+	trace_xfs_refcount_get(cur->bc_mp, pag->pag_agno, irec);
 	return 0;
 
 out_bad_rec:
 	xfs_warn(mp,
-		"Refcount BTree record corruption in AG %d detected!", agno);
+		"Refcount BTree record corruption in AG %d detected!",
+		pag->pag_agno);
 	xfs_warn(mp,
 		"Start block 0x%x, block count 0x%x, references 0x%x",
 		irec->rc_startblock, irec->rc_blockcount, irec->rc_refcount);
@@ -1177,8 +1176,8 @@ xfs_refcount_finish_one(
 		*pcur = NULL;
 	}
 	if (rcur == NULL) {
-		error = xfs_alloc_read_agf(tp->t_mountp, tp, pag->pag_agno,
-				XFS_ALLOC_FLAG_FREEING, &agbp);
+		error = xfs_alloc_read_agf(pag, tp, XFS_ALLOC_FLAG_FREEING,
+				&agbp);
 		if (error)
 			goto out_drop;
 
@@ -1710,7 +1709,7 @@ xfs_refcount_recover_cow_leftovers(
 	if (error)
 		return error;
 
-	error = xfs_alloc_read_agf(mp, tp, pag->pag_agno, 0, &agbp);
+	error = xfs_alloc_read_agf(pag, tp, 0, &agbp);
 	if (error)
 		goto out_trans;
 	cur = xfs_refcountbt_init_cursor(mp, tp, agbp, pag);

fs/xfs/libxfs/xfs_refcount_btree.c

@@ -493,7 +493,7 @@ xfs_refcountbt_calc_reserves(
 	if (!xfs_has_reflink(mp))
 		return 0;
 
-	error = xfs_alloc_read_agf(mp, tp, pag->pag_agno, 0, &agbp);
+	error = xfs_alloc_read_agf(pag, tp, 0, &agbp);
 	if (error)
 		return error;
 
@@ -507,8 +507,7 @@ xfs_refcountbt_calc_reserves(
 	 * never be available for the kinds of things that would require btree
 	 * expansion.  We therefore can pretend the space isn't there.
 	 */
-	if (mp->m_sb.sb_logstart &&
-	    XFS_FSB_TO_AGNO(mp, mp->m_sb.sb_logstart) == pag->pag_agno)
+	if (xfs_ag_contains_log(mp, pag->pag_agno))
 		agblocks -= mp->m_sb.sb_logblocks;
 
 	*ask += xfs_refcountbt_max_size(mp, agblocks);

fs/xfs/libxfs/xfs_rmap.c

@@ -215,7 +215,7 @@ xfs_rmap_get_rec(
 	int			*stat)
 {
 	struct xfs_mount	*mp = cur->bc_mp;
-	xfs_agnumber_t		agno = cur->bc_ag.pag->pag_agno;
+	struct xfs_perag	*pag = cur->bc_ag.pag;
 	union xfs_btree_rec	*rec;
 	int			error;
 
@@ -235,12 +235,12 @@ xfs_rmap_get_rec(
 			goto out_bad_rec;
 	} else {
 		/* check for valid extent range, including overflow */
-		if (!xfs_verify_agbno(mp, agno, irec->rm_startblock))
+		if (!xfs_verify_agbno(pag, irec->rm_startblock))
 			goto out_bad_rec;
 		if (irec->rm_startblock >
 				irec->rm_startblock + irec->rm_blockcount)
 			goto out_bad_rec;
-		if (!xfs_verify_agbno(mp, agno,
+		if (!xfs_verify_agbno(pag,
 				irec->rm_startblock + irec->rm_blockcount - 1))
 			goto out_bad_rec;
 	}
@@ -254,7 +254,7 @@ xfs_rmap_get_rec(
 out_bad_rec:
 	xfs_warn(mp,
 		"Reverse Mapping BTree record corruption in AG %d detected!",
-		agno);
+		pag->pag_agno);
 	xfs_warn(mp,
 		"Owner 0x%llx, flags 0x%x, start block 0x%x block count 0x%x",
 		irec->rm_owner, irec->rm_flags, irec->rm_startblock,

fs/xfs/libxfs/xfs_rmap_btree.c

@@ -90,7 +90,7 @@ xfs_rmapbt_alloc_block(
 	xfs_agblock_t		bno;
 
 	/* Allocate the new block from the freelist. If we can't, give up.  */
-	error = xfs_alloc_get_freelist(cur->bc_tp, cur->bc_ag.agbp,
+	error = xfs_alloc_get_freelist(pag, cur->bc_tp, cur->bc_ag.agbp,
 				       &bno, 1);
 	if (error)
 		return error;
@@ -129,7 +129,7 @@ xfs_rmapbt_free_block(
 			bno, 1);
 	be32_add_cpu(&agf->agf_rmap_blocks, -1);
 	xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_RMAP_BLOCKS);
-	error = xfs_alloc_put_freelist(cur->bc_tp, agbp, NULL, bno, 1);
+	error = xfs_alloc_put_freelist(pag, cur->bc_tp, agbp, NULL, bno, 1);
 	if (error)
 		return error;
 
@@ -652,7 +652,7 @@ xfs_rmapbt_calc_reserves(
 	if (!xfs_has_rmapbt(mp))
 		return 0;
 
-	error = xfs_alloc_read_agf(mp, tp, pag->pag_agno, 0, &agbp);
+	error = xfs_alloc_read_agf(pag, tp, 0, &agbp);
 	if (error)
 		return error;
 
@@ -666,8 +666,7 @@ xfs_rmapbt_calc_reserves(
 	 * never be available for the kinds of things that would require btree
 	 * expansion.  We therefore can pretend the space isn't there.
 	 */
-	if (mp->m_sb.sb_logstart &&
-	    XFS_FSB_TO_AGNO(mp, mp->m_sb.sb_logstart) == pag->pag_agno)
+	if (xfs_ag_contains_log(mp, pag->pag_agno))
 		agblocks -= mp->m_sb.sb_logblocks;
 
 	/* Reserve 1% of the AG or enough for 1 block per record. */

fs/xfs/libxfs/xfs_types.c

@@ -13,25 +13,13 @@
 #include "xfs_mount.h"
 #include "xfs_ag.h"
 
-/* Find the size of the AG, in blocks. */
-inline xfs_agblock_t
-xfs_ag_block_count(
-	struct xfs_mount	*mp,
-	xfs_agnumber_t		agno)
-{
-	ASSERT(agno < mp->m_sb.sb_agcount);
-
-	if (agno < mp->m_sb.sb_agcount - 1)
-		return mp->m_sb.sb_agblocks;
-	return mp->m_sb.sb_dblocks - (agno * mp->m_sb.sb_agblocks);
-}
 
 /*
  * Verify that an AG block number pointer neither points outside the AG
  * nor points at static metadata.
  */
-inline bool
-xfs_verify_agbno(
+static inline bool
+xfs_verify_agno_agbno(
 	struct xfs_mount	*mp,
 	xfs_agnumber_t		agno,
 	xfs_agblock_t		agbno)
@@ -59,7 +47,7 @@ xfs_verify_fsbno(
 
 	if (agno >= mp->m_sb.sb_agcount)
 		return false;
-	return xfs_verify_agbno(mp, agno, XFS_FSB_TO_AGBNO(mp, fsbno));
+	return xfs_verify_agno_agbno(mp, agno, XFS_FSB_TO_AGBNO(mp, fsbno));
 }
 
 /*
@@ -85,40 +73,12 @@ xfs_verify_fsbext(
 		XFS_FSB_TO_AGNO(mp, fsbno + len - 1);
 }
 
-/* Calculate the first and last possible inode number in an AG. */
-inline void
-xfs_agino_range(
-	struct xfs_mount	*mp,
-	xfs_agnumber_t		agno,
-	xfs_agino_t		*first,
-	xfs_agino_t		*last)
-{
-	xfs_agblock_t		bno;
-	xfs_agblock_t		eoag;
-
-	eoag = xfs_ag_block_count(mp, agno);
-
-	/*
-	 * Calculate the first inode, which will be in the first
-	 * cluster-aligned block after the AGFL.
-	 */
-	bno = round_up(XFS_AGFL_BLOCK(mp) + 1, M_IGEO(mp)->cluster_align);
-	*first = XFS_AGB_TO_AGINO(mp, bno);
-
-	/*
-	 * Calculate the last inode, which will be at the end of the
-	 * last (aligned) cluster that can be allocated in the AG.
-	 */
-	bno = round_down(eoag, M_IGEO(mp)->cluster_align);
-	*last = XFS_AGB_TO_AGINO(mp, bno) - 1;
-}
-
 /*
  * Verify that an AG inode number pointer neither points outside the AG
  * nor points at static metadata.
  */
-inline bool
-xfs_verify_agino(
+static inline bool
+xfs_verify_agno_agino(
 	struct xfs_mount	*mp,
 	xfs_agnumber_t		agno,
 	xfs_agino_t		agino)
@@ -130,19 +90,6 @@ xfs_verify_agino(
 	return agino >= first && agino <= last;
 }
 
-/*
- * Verify that an AG inode number pointer neither points outside the AG
- * nor points at static metadata, or is NULLAGINO.
- */
-bool
-xfs_verify_agino_or_null(
-	struct xfs_mount	*mp,
-	xfs_agnumber_t		agno,
-	xfs_agino_t		agino)
-{
-	return agino == NULLAGINO || xfs_verify_agino(mp, agno, agino);
-}
-
 /*
  * Verify that an FS inode number pointer neither points outside the
  * filesystem nor points at static AG metadata.
@@ -159,7 +106,7 @@ xfs_verify_ino(
 		return false;
 	if (XFS_AGINO_TO_INO(mp, agno, agino) != ino)
 		return false;
-	return xfs_verify_agino(mp, agno, agino);
+	return xfs_verify_agno_agino(mp, agno, agino);
 }
 
 /* Is this an internal inode number? */
@@ -229,12 +176,8 @@ xfs_icount_range(
 	/* root, rtbitmap, rtsum all live in the first chunk */
 	*min = XFS_INODES_PER_CHUNK;
 
-	for_each_perag(mp, agno, pag) {
-		xfs_agino_t	first, last;
-
-		xfs_agino_range(mp, agno, &first, &last);
-		nr_inos += last - first + 1;
-	}
+	for_each_perag(mp, agno, pag)
+		nr_inos += pag->agino_max - pag->agino_min + 1;
 	*max = nr_inos;
 }
 

fs/xfs/libxfs/xfs_types.h

@@ -179,19 +179,10 @@ enum xfs_ag_resv_type {
  */
 struct xfs_mount;
 
-xfs_agblock_t xfs_ag_block_count(struct xfs_mount *mp, xfs_agnumber_t agno);
-bool xfs_verify_agbno(struct xfs_mount *mp, xfs_agnumber_t agno,
-		xfs_agblock_t agbno);
 bool xfs_verify_fsbno(struct xfs_mount *mp, xfs_fsblock_t fsbno);
 bool xfs_verify_fsbext(struct xfs_mount *mp, xfs_fsblock_t fsbno,
 		xfs_fsblock_t len);
 
-void xfs_agino_range(struct xfs_mount *mp, xfs_agnumber_t agno,
-		xfs_agino_t *first, xfs_agino_t *last);
-bool xfs_verify_agino(struct xfs_mount *mp, xfs_agnumber_t agno,
-		xfs_agino_t agino);
-bool xfs_verify_agino_or_null(struct xfs_mount *mp, xfs_agnumber_t agno,
-		xfs_agino_t agino);
 bool xfs_verify_ino(struct xfs_mount *mp, xfs_ino_t ino);
 bool xfs_internal_inum(struct xfs_mount *mp, xfs_ino_t ino);
 bool xfs_verify_dir_ino(struct xfs_mount *mp, xfs_ino_t ino);

fs/xfs/scrub/agheader.c

@@ -541,16 +541,16 @@ xchk_agf(
 
 	/* Check the AG length */
 	eoag = be32_to_cpu(agf->agf_length);
-	if (eoag != xfs_ag_block_count(mp, agno))
+	if (eoag != pag->block_count)
 		xchk_block_set_corrupt(sc, sc->sa.agf_bp);
 
 	/* Check the AGF btree roots and levels */
 	agbno = be32_to_cpu(agf->agf_roots[XFS_BTNUM_BNO]);
-	if (!xfs_verify_agbno(mp, agno, agbno))
+	if (!xfs_verify_agbno(pag, agbno))
 		xchk_block_set_corrupt(sc, sc->sa.agf_bp);
 
 	agbno = be32_to_cpu(agf->agf_roots[XFS_BTNUM_CNT]);
-	if (!xfs_verify_agbno(mp, agno, agbno))
+	if (!xfs_verify_agbno(pag, agbno))
 		xchk_block_set_corrupt(sc, sc->sa.agf_bp);
 
 	level = be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNO]);
@@ -563,7 +563,7 @@ xchk_agf(
 
 	if (xfs_has_rmapbt(mp)) {
 		agbno = be32_to_cpu(agf->agf_roots[XFS_BTNUM_RMAP]);
-		if (!xfs_verify_agbno(mp, agno, agbno))
+		if (!xfs_verify_agbno(pag, agbno))
 			xchk_block_set_corrupt(sc, sc->sa.agf_bp);
 
 		level = be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]);
@@ -573,7 +573,7 @@ xchk_agf(
 
 	if (xfs_has_reflink(mp)) {
 		agbno = be32_to_cpu(agf->agf_refcount_root);
-		if (!xfs_verify_agbno(mp, agno, agbno))
+		if (!xfs_verify_agbno(pag, agbno))
 			xchk_block_set_corrupt(sc, sc->sa.agf_bp);
 
 		level = be32_to_cpu(agf->agf_refcount_level);
@@ -639,9 +639,8 @@ xchk_agfl_block(
 {
 	struct xchk_agfl_info	*sai = priv;
 	struct xfs_scrub	*sc = sai->sc;
-	xfs_agnumber_t		agno = sc->sa.pag->pag_agno;
 
-	if (xfs_verify_agbno(mp, agno, agbno) &&
+	if (xfs_verify_agbno(sc->sa.pag, agbno) &&
 	    sai->nr_entries < sai->sz_entries)
 		sai->entries[sai->nr_entries++] = agbno;
 	else
@@ -871,12 +870,12 @@ xchk_agi(
 
 	/* Check the AG length */
 	eoag = be32_to_cpu(agi->agi_length);
-	if (eoag != xfs_ag_block_count(mp, agno))
+	if (eoag != pag->block_count)
 		xchk_block_set_corrupt(sc, sc->sa.agi_bp);
 
 	/* Check btree roots and levels */
 	agbno = be32_to_cpu(agi->agi_root);
-	if (!xfs_verify_agbno(mp, agno, agbno))
+	if (!xfs_verify_agbno(pag, agbno))
 		xchk_block_set_corrupt(sc, sc->sa.agi_bp);
 
 	level = be32_to_cpu(agi->agi_level);
@@ -885,7 +884,7 @@ xchk_agi(
 
 	if (xfs_has_finobt(mp)) {
 		agbno = be32_to_cpu(agi->agi_free_root);
-		if (!xfs_verify_agbno(mp, agno, agbno))
+		if (!xfs_verify_agbno(pag, agbno))
 			xchk_block_set_corrupt(sc, sc->sa.agi_bp);
 
 		level = be32_to_cpu(agi->agi_free_level);
@@ -902,17 +901,17 @@ xchk_agi(
 
 	/* Check inode pointers */
 	agino = be32_to_cpu(agi->agi_newino);
-	if (!xfs_verify_agino_or_null(mp, agno, agino))
+	if (!xfs_verify_agino_or_null(pag, agino))
 		xchk_block_set_corrupt(sc, sc->sa.agi_bp);
 
 	agino = be32_to_cpu(agi->agi_dirino);
-	if (!xfs_verify_agino_or_null(mp, agno, agino))
+	if (!xfs_verify_agino_or_null(pag, agino))
 		xchk_block_set_corrupt(sc, sc->sa.agi_bp);
 
 	/* Check unlinked inode buckets */
 	for (i = 0; i < XFS_AGI_UNLINKED_BUCKETS; i++) {
 		agino = be32_to_cpu(agi->agi_unlinked[i]);
-		if (!xfs_verify_agino_or_null(mp, agno, agino))
+		if (!xfs_verify_agino_or_null(pag, agino))
 			xchk_block_set_corrupt(sc, sc->sa.agi_bp);
 	}
 

fs/xfs/scrub/agheader_repair.c

@@ -106,7 +106,7 @@ xrep_agf_check_agfl_block(
 {
 	struct xfs_scrub	*sc = priv;
 
-	if (!xfs_verify_agbno(mp, sc->sa.pag->pag_agno, agbno))
+	if (!xfs_verify_agbno(sc->sa.pag, agbno))
 		return -EFSCORRUPTED;
 	return 0;
 }
@@ -130,10 +130,7 @@ xrep_check_btree_root(
 	struct xfs_scrub		*sc,
 	struct xrep_find_ag_btree	*fab)
 {
-	struct xfs_mount		*mp = sc->mp;
-	xfs_agnumber_t			agno = sc->sm->sm_agno;
-
-	return xfs_verify_agbno(mp, agno, fab->root) &&
+	return xfs_verify_agbno(sc->sa.pag, fab->root) &&
 	       fab->height <= fab->maxlevels;
 }
 
@@ -201,8 +198,7 @@ xrep_agf_init_header(
 	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(xfs_ag_block_count(mp,
-							sc->sa.pag->pag_agno));
+	agf->agf_length = cpu_to_be32(sc->sa.pag->block_count);
 	agf->agf_flfirst = old_agf->agf_flfirst;
 	agf->agf_fllast = old_agf->agf_fllast;
 	agf->agf_flcount = old_agf->agf_flcount;
@@ -405,7 +401,7 @@ xrep_agf(
 	 * btrees rooted in the AGF.  If the AGFL contents are obviously bad
 	 * then we'll bail out.
 	 */
-	error = xfs_alloc_read_agfl(mp, sc->tp, sc->sa.pag->pag_agno, &agfl_bp);
+	error = xfs_alloc_read_agfl(sc->sa.pag, sc->tp, &agfl_bp);
 	if (error)
 		return error;
 
@@ -666,8 +662,7 @@ xrep_agfl(
 	 * nothing wrong with the AGF, but all the AG header repair functions
 	 * have this chicken-and-egg problem.
 	 */
-	error = xfs_alloc_read_agf(mp, sc->tp, sc->sa.pag->pag_agno, 0,
-			&agf_bp);
+	error = xfs_alloc_read_agf(sc->sa.pag, sc->tp, 0, &agf_bp);
 	if (error)
 		return error;
 
@@ -742,8 +737,7 @@ xrep_agi_find_btrees(
 	int				error;
 
 	/* Read the AGF. */
-	error = xfs_alloc_read_agf(mp, sc->tp, sc->sa.pag->pag_agno, 0,
-			&agf_bp);
+	error = xfs_alloc_read_agf(sc->sa.pag, sc->tp, 0, &agf_bp);
 	if (error)
 		return error;
 
@@ -782,8 +776,7 @@ xrep_agi_init_header(
 	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(xfs_ag_block_count(mp,
-							sc->sa.pag->pag_agno));
+	agi->agi_length = cpu_to_be32(sc->sa.pag->block_count);
 	agi->agi_newino = cpu_to_be32(NULLAGINO);
 	agi->agi_dirino = cpu_to_be32(NULLAGINO);
 	if (xfs_has_crc(mp))

fs/xfs/scrub/alloc.c

@@ -93,8 +93,7 @@ xchk_allocbt_rec(
 	struct xchk_btree	*bs,
 	const union xfs_btree_rec *rec)
 {
-	struct xfs_mount	*mp = bs->cur->bc_mp;
-	xfs_agnumber_t		agno = bs->cur->bc_ag.pag->pag_agno;
+	struct xfs_perag	*pag = bs->cur->bc_ag.pag;
 	xfs_agblock_t		bno;
 	xfs_extlen_t		len;
 
@@ -102,8 +101,8 @@ xchk_allocbt_rec(
 	len = be32_to_cpu(rec->alloc.ar_blockcount);
 
 	if (bno + len <= bno ||
-	    !xfs_verify_agbno(mp, agno, bno) ||
-	    !xfs_verify_agbno(mp, agno, bno + len - 1))
+	    !xfs_verify_agbno(pag, bno) ||
+	    !xfs_verify_agbno(pag, bno + len - 1))
 		xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
 
 	xchk_allocbt_xref(bs->sc, bno, len);

fs/xfs/scrub/bmap.c

@@ -540,7 +540,7 @@ xchk_bmap_check_ag_rmaps(
 	struct xfs_buf			*agf;
 	int				error;
 
-	error = xfs_alloc_read_agf(sc->mp, sc->tp, pag->pag_agno, 0, &agf);
+	error = xfs_alloc_read_agf(pag, sc->tp, 0, &agf);
 	if (error)
 		return error;
 

fs/xfs/scrub/common.c

@@ -416,15 +416,15 @@ xchk_ag_read_headers(
 	if (!sa->pag)
 		return -ENOENT;
 
-	error = xfs_ialloc_read_agi(mp, sc->tp, agno, &sa->agi_bp);
+	error = xfs_ialloc_read_agi(sa->pag, sc->tp, &sa->agi_bp);
 	if (error && want_ag_read_header_failure(sc, XFS_SCRUB_TYPE_AGI))
 		return error;
 
-	error = xfs_alloc_read_agf(mp, sc->tp, agno, 0, &sa->agf_bp);
+	error = xfs_alloc_read_agf(sa->pag, sc->tp, 0, &sa->agf_bp);
 	if (error && want_ag_read_header_failure(sc, XFS_SCRUB_TYPE_AGF))
 		return error;
 
-	error = xfs_alloc_read_agfl(mp, sc->tp, agno, &sa->agfl_bp);
+	error = xfs_alloc_read_agfl(sa->pag, sc->tp, &sa->agfl_bp);
 	if (error && want_ag_read_header_failure(sc, XFS_SCRUB_TYPE_AGFL))
 		return error;
 

fs/xfs/scrub/fscounters.c

@@ -78,10 +78,10 @@ xchk_fscount_warmup(
 			continue;
 
 		/* Lock both AG headers. */
-		error = xfs_ialloc_read_agi(mp, sc->tp, agno, &agi_bp);
+		error = xfs_ialloc_read_agi(pag, sc->tp, &agi_bp);
 		if (error)
 			break;
-		error = xfs_alloc_read_agf(mp, sc->tp, agno, 0, &agf_bp);
+		error = xfs_alloc_read_agf(pag, sc->tp, 0, &agf_bp);
 		if (error)
 			break;
 

fs/xfs/scrub/health.c

@@ -8,6 +8,8 @@
 #include "xfs_shared.h"
 #include "xfs_format.h"
 #include "xfs_btree.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
 #include "xfs_ag.h"
 #include "xfs_health.h"
 #include "scrub/scrub.h"

fs/xfs/scrub/ialloc.c

@@ -104,13 +104,13 @@ xchk_iallocbt_chunk(
 	xfs_extlen_t			len)
 {
 	struct xfs_mount		*mp = bs->cur->bc_mp;
-	xfs_agnumber_t			agno = bs->cur->bc_ag.pag->pag_agno;
+	struct xfs_perag		*pag = bs->cur->bc_ag.pag;
 	xfs_agblock_t			bno;
 
 	bno = XFS_AGINO_TO_AGBNO(mp, agino);
 	if (bno + len <= bno ||
-	    !xfs_verify_agbno(mp, agno, bno) ||
-	    !xfs_verify_agbno(mp, agno, bno + len - 1))
+	    !xfs_verify_agbno(pag, bno) ||
+	    !xfs_verify_agbno(pag, bno + len - 1))
 		xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
 
 	xchk_iallocbt_chunk_xref(bs->sc, irec, agino, bno, len);
@@ -421,10 +421,10 @@ xchk_iallocbt_rec(
 	const union xfs_btree_rec	*rec)
 {
 	struct xfs_mount		*mp = bs->cur->bc_mp;
+	struct xfs_perag		*pag = bs->cur->bc_ag.pag;
 	struct xchk_iallocbt		*iabt = bs->private;
 	struct xfs_inobt_rec_incore	irec;
 	uint64_t			holes;
-	xfs_agnumber_t			agno = bs->cur->bc_ag.pag->pag_agno;
 	xfs_agino_t			agino;
 	xfs_extlen_t			len;
 	int				holecount;
@@ -446,8 +446,8 @@ xchk_iallocbt_rec(
 
 	agino = irec.ir_startino;
 	/* Record has to be properly aligned within the AG. */
-	if (!xfs_verify_agino(mp, agno, agino) ||
-	    !xfs_verify_agino(mp, agno, agino + XFS_INODES_PER_CHUNK - 1)) {
+	if (!xfs_verify_agino(pag, agino) ||
+	    !xfs_verify_agino(pag, agino + XFS_INODES_PER_CHUNK - 1)) {
 		xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
 		goto out;
 	}

fs/xfs/scrub/refcount.c

@@ -13,6 +13,8 @@
 #include "scrub/scrub.h"
 #include "scrub/common.h"
 #include "scrub/btree.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
 #include "xfs_ag.h"
 
 /*
@@ -332,9 +334,8 @@ xchk_refcountbt_rec(
 	struct xchk_btree	*bs,
 	const union xfs_btree_rec *rec)
 {
-	struct xfs_mount	*mp = bs->cur->bc_mp;
 	xfs_agblock_t		*cow_blocks = bs->private;
-	xfs_agnumber_t		agno = bs->cur->bc_ag.pag->pag_agno;
+	struct xfs_perag	*pag = bs->cur->bc_ag.pag;
 	xfs_agblock_t		bno;
 	xfs_extlen_t		len;
 	xfs_nlink_t		refcount;
@@ -354,8 +355,8 @@ xchk_refcountbt_rec(
 	/* Check the extent. */
 	bno &= ~XFS_REFC_COW_START;
 	if (bno + len <= bno ||
-	    !xfs_verify_agbno(mp, agno, bno) ||
-	    !xfs_verify_agbno(mp, agno, bno + len - 1))
+	    !xfs_verify_agbno(pag, bno) ||
+	    !xfs_verify_agbno(pag, bno + len - 1))
 		xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
 
 	if (refcount == 0)

fs/xfs/scrub/repair.c

@@ -199,7 +199,7 @@ xrep_calc_ag_resblks(
 		icount = pag->pagi_count;
 	} else {
 		/* Try to get the actual counters from disk. */
-		error = xfs_ialloc_read_agi(mp, NULL, sm->sm_agno, &bp);
+		error = xfs_ialloc_read_agi(pag, NULL, &bp);
 		if (!error) {
 			icount = pag->pagi_count;
 			xfs_buf_relse(bp);
@@ -207,9 +207,9 @@ xrep_calc_ag_resblks(
 	}
 
 	/* Now grab the block counters from the AGF. */
-	error = xfs_alloc_read_agf(mp, NULL, sm->sm_agno, 0, &bp);
+	error = xfs_alloc_read_agf(pag, NULL, 0, &bp);
 	if (error) {
-		aglen = xfs_ag_block_count(mp, sm->sm_agno);
+		aglen = pag->block_count;
 		freelen = aglen;
 		usedlen = aglen;
 	} else {
@@ -220,25 +220,22 @@ xrep_calc_ag_resblks(
 		usedlen = aglen - freelen;
 		xfs_buf_relse(bp);
 	}
-	xfs_perag_put(pag);
 
 	/* If the icount is impossible, make some worst-case assumptions. */
 	if (icount == NULLAGINO ||
-	    !xfs_verify_agino(mp, sm->sm_agno, icount)) {
-		xfs_agino_t	first, last;
-
-		xfs_agino_range(mp, sm->sm_agno, &first, &last);
-		icount = last - first + 1;
+	    !xfs_verify_agino(pag, icount)) {
+		icount = pag->agino_max - pag->agino_min + 1;
 	}
 
 	/* If the block counts are impossible, make worst-case assumptions. */
 	if (aglen == NULLAGBLOCK ||
-	    aglen != xfs_ag_block_count(mp, sm->sm_agno) ||
+	    aglen != pag->block_count ||
 	    freelen >= aglen) {
-		aglen = xfs_ag_block_count(mp, sm->sm_agno);
+		aglen = pag->block_count;
 		freelen = aglen;
 		usedlen = aglen;
 	}
+	xfs_perag_put(pag);
 
 	trace_xrep_calc_ag_resblks(mp, sm->sm_agno, icount, aglen,
 			freelen, usedlen);
@@ -300,13 +297,13 @@ xrep_alloc_ag_block(
 	switch (resv) {
 	case XFS_AG_RESV_AGFL:
 	case XFS_AG_RESV_RMAPBT:
-		error = xfs_alloc_get_freelist(sc->tp, sc->sa.agf_bp, &bno, 1);
+		error = xfs_alloc_get_freelist(sc->sa.pag, sc->tp,
+				sc->sa.agf_bp, &bno, 1);
 		if (error)
 			return error;
 		if (bno == NULLAGBLOCK)
 			return -ENOSPC;
-		xfs_extent_busy_reuse(sc->mp, sc->sa.pag, bno,
-				1, false);
+		xfs_extent_busy_reuse(sc->mp, sc->sa.pag, bno, 1, false);
 		*fsbno = XFS_AGB_TO_FSB(sc->mp, sc->sa.pag->pag_agno, bno);
 		if (resv == XFS_AG_RESV_RMAPBT)
 			xfs_ag_resv_rmapbt_alloc(sc->mp, sc->sa.pag->pag_agno);
@@ -516,8 +513,8 @@ xrep_put_freelist(
 		return error;
 
 	/* Put the block on the AGFL. */
-	error = xfs_alloc_put_freelist(sc->tp, sc->sa.agf_bp, sc->sa.agfl_bp,
-			agbno, 0);
+	error = xfs_alloc_put_freelist(sc->sa.pag, sc->tp, sc->sa.agf_bp,
+			sc->sa.agfl_bp, agbno, 0);
 	if (error)
 		return error;
 	xfs_extent_busy_insert(sc->tp, sc->sa.pag, agbno, 1,
@@ -543,6 +540,7 @@ xrep_reap_block(
 
 	agno = XFS_FSB_TO_AGNO(sc->mp, fsbno);
 	agbno = XFS_FSB_TO_AGBNO(sc->mp, fsbno);
+	ASSERT(agno == sc->sa.pag->pag_agno);
 
 	/*
 	 * If we are repairing per-inode metadata, we need to read in the AGF
@@ -550,7 +548,7 @@ xrep_reap_block(
 	 * the AGF buffer that the setup functions already grabbed.
 	 */
 	if (sc->ip) {
-		error = xfs_alloc_read_agf(sc->mp, sc->tp, agno, 0, &agf_bp);
+		error = xfs_alloc_read_agf(sc->sa.pag, sc->tp, 0, &agf_bp);
 		if (error)
 			return error;
 	} else {

fs/xfs/scrub/rmap.c

@@ -92,7 +92,7 @@ xchk_rmapbt_rec(
 {
 	struct xfs_mount	*mp = bs->cur->bc_mp;
 	struct xfs_rmap_irec	irec;
-	xfs_agnumber_t		agno = bs->cur->bc_ag.pag->pag_agno;
+	struct xfs_perag	*pag = bs->cur->bc_ag.pag;
 	bool			non_inode;
 	bool			is_unwritten;
 	bool			is_bmbt;
@@ -121,8 +121,8 @@ xchk_rmapbt_rec(
 		 * Otherwise we must point somewhere past the static metadata
 		 * but before the end of the FS.  Run the regular check.
 		 */
-		if (!xfs_verify_agbno(mp, agno, irec.rm_startblock) ||
-		    !xfs_verify_agbno(mp, agno, irec.rm_startblock +
+		if (!xfs_verify_agbno(pag, irec.rm_startblock) ||
+		    !xfs_verify_agbno(pag, irec.rm_startblock +
 				irec.rm_blockcount - 1))
 			xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
 	}

fs/xfs/xfs_discard.c

@@ -45,7 +45,7 @@ xfs_trim_extents(
 	 */
 	xfs_log_force(mp, XFS_LOG_SYNC);
 
-	error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
+	error = xfs_alloc_read_agf(pag, NULL, 0, &agbp);
 	if (error)
 		goto out_put_perag;
 	agf = agbp->b_addr;

fs/xfs/xfs_extfree_item.c

@@ -11,6 +11,7 @@
 #include "xfs_bit.h"
 #include "xfs_shared.h"
 #include "xfs_mount.h"
+#include "xfs_ag.h"
 #include "xfs_defer.h"
 #include "xfs_trans.h"
 #include "xfs_trans_priv.h"
@@ -551,6 +552,7 @@ xfs_agfl_free_finish_item(
 	xfs_agnumber_t			agno;
 	xfs_agblock_t			agbno;
 	uint				next_extent;
+	struct xfs_perag		*pag;
 
 	free = container_of(item, struct xfs_extent_free_item, xefi_list);
 	ASSERT(free->xefi_blockcount == 1);
@@ -560,9 +562,11 @@ xfs_agfl_free_finish_item(
 
 	trace_xfs_agfl_free_deferred(mp, agno, 0, agbno, free->xefi_blockcount);
 
-	error = xfs_alloc_read_agf(mp, tp, agno, 0, &agbp);
+	pag = xfs_perag_get(mp, agno);
+	error = xfs_alloc_read_agf(pag, tp, 0, &agbp);
 	if (!error)
 		error = xfs_free_agfl_block(tp, agno, agbno, agbp, &oinfo);
+	xfs_perag_put(pag);
 
 	/*
 	 * Mark the transaction dirty, even on error. This ensures the

fs/xfs/xfs_filestream.c

@@ -126,7 +126,7 @@ xfs_filestream_pick_ag(
 		pag = xfs_perag_get(mp, ag);
 
 		if (!pag->pagf_init) {
-			err = xfs_alloc_pagf_init(mp, NULL, ag, trylock);
+			err = xfs_alloc_read_agf(pag, NULL, trylock, NULL);
 			if (err) {
 				if (err != -EAGAIN) {
 					xfs_perag_put(pag);
@@ -181,7 +181,7 @@ xfs_filestream_pick_ag(
 		if (ag != startag)
 			continue;
 
-		/* Allow sleeping in xfs_alloc_pagf_init() on the 2nd pass. */
+		/* Allow sleeping in xfs_alloc_read_agf() on the 2nd pass. */
 		if (trylock != 0) {
 			trylock = 0;
 			continue;

fs/xfs/xfs_fsmap.c

@@ -642,8 +642,7 @@ __xfs_getfsmap_datadev(
 			info->agf_bp = NULL;
 		}
 
-		error = xfs_alloc_read_agf(mp, tp, pag->pag_agno, 0,
-				&info->agf_bp);
+		error = xfs_alloc_read_agf(pag, tp, 0, &info->agf_bp);
 		if (error)
 			break;
 

fs/xfs/xfs_fsops.c

@@ -41,6 +41,7 @@ xfs_resizefs_init_new_ags(
 	xfs_agnumber_t		oagcount,
 	xfs_agnumber_t		nagcount,
 	xfs_rfsblock_t		delta,
+	struct xfs_perag	*last_pag,
 	bool			*lastag_extended)
 {
 	struct xfs_mount	*mp = tp->t_mountp;
@@ -73,7 +74,7 @@ xfs_resizefs_init_new_ags(
 
 	if (delta) {
 		*lastag_extended = true;
-		error = xfs_ag_extend_space(mp, tp, id, delta);
+		error = xfs_ag_extend_space(last_pag, tp, delta);
 	}
 	return error;
 }
@@ -96,6 +97,7 @@ xfs_growfs_data_private(
 	xfs_agnumber_t		oagcount;
 	struct xfs_trans	*tp;
 	struct aghdr_init_data	id = {};
+	struct xfs_perag	*last_pag;
 
 	nb = in->newblocks;
 	error = xfs_sb_validate_fsb_count(&mp->m_sb, nb);
@@ -128,10 +130,9 @@ xfs_growfs_data_private(
 		return -EINVAL;
 
 	oagcount = mp->m_sb.sb_agcount;
-
 	/* allocate the new per-ag structures */
 	if (nagcount > oagcount) {
-		error = xfs_initialize_perag(mp, nagcount, &nagimax);
+		error = xfs_initialize_perag(mp, nagcount, nb, &nagimax);
 		if (error)
 			return error;
 	} else if (nagcount < oagcount) {
@@ -145,15 +146,17 @@ xfs_growfs_data_private(
 	if (error)
 		return error;
 
+	last_pag = xfs_perag_get(mp, oagcount - 1);
 	if (delta > 0) {
 		error = xfs_resizefs_init_new_ags(tp, &id, oagcount, nagcount,
-						  delta, &lastag_extended);
+				delta, last_pag, &lastag_extended);
 	} else {
 		xfs_warn_mount(mp, XFS_OPSTATE_WARNED_SHRINK,
 	"EXPERIMENTAL online shrink feature in use. Use at your own risk!");
 
-		error = xfs_ag_shrink_space(mp, &tp, nagcount - 1, -delta);
+		error = xfs_ag_shrink_space(last_pag, &tp, -delta);
 	}
+	xfs_perag_put(last_pag);
 	if (error)
 		goto out_trans_cancel;
 

fs/xfs/xfs_inode.c

@@ -2008,7 +2008,7 @@ xfs_iunlink_update_bucket(
 	xfs_agino_t		old_value;
 	int			offset;
 
-	ASSERT(xfs_verify_agino_or_null(tp->t_mountp, pag->pag_agno, new_agino));
+	ASSERT(xfs_verify_agino_or_null(pag, new_agino));
 
 	old_value = be32_to_cpu(agi->agi_unlinked[bucket_index]);
 	trace_xfs_iunlink_update_bucket(tp->t_mountp, pag->pag_agno, bucket_index,
@@ -2045,7 +2045,7 @@ xfs_iunlink_update_dinode(
 	struct xfs_mount	*mp = tp->t_mountp;
 	int			offset;
 
-	ASSERT(xfs_verify_agino_or_null(mp, pag->pag_agno, next_agino));
+	ASSERT(xfs_verify_agino_or_null(pag, next_agino));
 
 	trace_xfs_iunlink_update_dinode(mp, pag->pag_agno, agino,
 			be32_to_cpu(dip->di_next_unlinked), next_agino);
@@ -2075,7 +2075,7 @@ xfs_iunlink_update_inode(
 	xfs_agino_t		old_value;
 	int			error;
 
-	ASSERT(xfs_verify_agino_or_null(mp, pag->pag_agno, next_agino));
+	ASSERT(xfs_verify_agino_or_null(pag, next_agino));
 
 	error = xfs_imap_to_bp(mp, tp, &ip->i_imap, &ibp);
 	if (error)
@@ -2084,7 +2084,7 @@ xfs_iunlink_update_inode(
 
 	/* Make sure the old pointer isn't garbage. */
 	old_value = be32_to_cpu(dip->di_next_unlinked);
-	if (!xfs_verify_agino_or_null(mp, pag->pag_agno, old_value)) {
+	if (!xfs_verify_agino_or_null(pag, old_value)) {
 		xfs_inode_verifier_error(ip, -EFSCORRUPTED, __func__, dip,
 				sizeof(*dip), __this_address);
 		error = -EFSCORRUPTED;
@@ -2143,7 +2143,7 @@ xfs_iunlink(
 	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
 
 	/* Get the agi buffer first.  It ensures lock ordering on the list. */
-	error = xfs_read_agi(mp, tp, pag->pag_agno, &agibp);
+	error = xfs_read_agi(pag, tp, &agibp);
 	if (error)
 		goto out;
 	agi = agibp->b_addr;
@@ -2155,7 +2155,7 @@ xfs_iunlink(
 	 */
 	next_agino = be32_to_cpu(agi->agi_unlinked[bucket_index]);
 	if (next_agino == agino ||
-	    !xfs_verify_agino_or_null(mp, pag->pag_agno, next_agino)) {
+	    !xfs_verify_agino_or_null(pag, next_agino)) {
 		xfs_buf_mark_corrupt(agibp);
 		error = -EFSCORRUPTED;
 		goto out;
@@ -2291,7 +2291,7 @@ xfs_iunlink_map_prev(
 		 * Make sure this pointer is valid and isn't an obvious
 		 * infinite loop.
 		 */
-		if (!xfs_verify_agino(mp, pag->pag_agno, unlinked_agino) ||
+		if (!xfs_verify_agino(pag, unlinked_agino) ||
 		    next_agino == unlinked_agino) {
 			XFS_CORRUPTION_ERROR(__func__,
 					XFS_ERRLEVEL_LOW, mp,
@@ -2328,7 +2328,7 @@ xfs_iunlink_remove(
 	trace_xfs_iunlink_remove(ip);
 
 	/* Get the agi buffer first.  It ensures lock ordering on the list. */
-	error = xfs_read_agi(mp, tp, pag->pag_agno, &agibp);
+	error = xfs_read_agi(pag, tp, &agibp);
 	if (error)
 		return error;
 	agi = agibp->b_addr;
@@ -2338,7 +2338,7 @@ xfs_iunlink_remove(
 	 * go on.  Make sure the head pointer isn't garbage.
 	 */
 	head_agino = be32_to_cpu(agi->agi_unlinked[bucket_index]);
-	if (!xfs_verify_agino(mp, pag->pag_agno, head_agino)) {
+	if (!xfs_verify_agino(pag, head_agino)) {
 		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
 				agi, sizeof(*agi));
 		return -EFSCORRUPTED;
@@ -3229,11 +3229,13 @@ xfs_rename(
 		if (inodes[i] == wip ||
 		    (inodes[i] == target_ip &&
 		     (VFS_I(target_ip)->i_nlink == 1 || src_is_directory))) {
+			struct xfs_perag	*pag;
 			struct xfs_buf		*bp;
-			xfs_agnumber_t	agno;
 
-			agno = XFS_INO_TO_AGNO(mp, inodes[i]->i_ino);
-			error = xfs_read_agi(mp, tp, agno, &bp);
+			pag = xfs_perag_get(mp,
+					XFS_INO_TO_AGNO(mp, inodes[i]->i_ino));
+			error = xfs_read_agi(pag, tp, &bp);
+			xfs_perag_put(pag);
 			if (error)
 				goto out_trans_cancel;
 		}

fs/xfs/xfs_ioctl.c

@@ -955,6 +955,7 @@ xfs_ioc_ag_geometry(
 	struct xfs_mount	*mp,
 	void			__user *arg)
 {
+	struct xfs_perag	*pag;
 	struct xfs_ag_geometry	ageo;
 	int			error;
 
@@ -965,7 +966,12 @@ xfs_ioc_ag_geometry(
 	if (memchr_inv(&ageo.ag_reserved, 0, sizeof(ageo.ag_reserved)))
 		return -EINVAL;
 
-	error = xfs_ag_get_geometry(mp, ageo.ag_number, &ageo);
+	pag = xfs_perag_get(mp, ageo.ag_number);
+	if (!pag)
+		return -EINVAL;
+
+	error = xfs_ag_get_geometry(pag, &ageo);
+	xfs_perag_put(pag);
 	if (error)
 		return error;
 

fs/xfs/xfs_log_recover.c

@@ -2629,12 +2629,12 @@ xlog_recover_cancel_intents(
  */
 STATIC void
 xlog_recover_clear_agi_bucket(
-	xfs_mount_t	*mp,
-	xfs_agnumber_t	agno,
+	struct xfs_perag	*pag,
 	int			bucket)
 {
-	xfs_trans_t	*tp;
-	xfs_agi_t	*agi;
+	struct xfs_mount	*mp = pag->pag_mount;
+	struct xfs_trans	*tp;
+	struct xfs_agi		*agi;
 	struct xfs_buf		*agibp;
 	int			offset;
 	int			error;
@@ -2643,7 +2643,7 @@ xlog_recover_clear_agi_bucket(
 	if (error)
 		goto out_error;
 
-	error = xfs_read_agi(mp, tp, agno, &agibp);
+	error = xfs_read_agi(pag, tp, &agibp);
 	if (error)
 		goto out_abort;
 
@@ -2662,14 +2662,14 @@ xlog_recover_clear_agi_bucket(
 out_abort:
 	xfs_trans_cancel(tp);
 out_error:
-	xfs_warn(mp, "%s: failed to clear agi %d. Continuing.", __func__, agno);
+	xfs_warn(mp, "%s: failed to clear agi %d. Continuing.", __func__,
+			pag->pag_agno);
 	return;
 }
 
 STATIC xfs_agino_t
 xlog_recover_process_one_iunlink(
-	struct xfs_mount		*mp,
-	xfs_agnumber_t			agno,
+	struct xfs_perag		*pag,
 	xfs_agino_t			agino,
 	int				bucket)
 {
@@ -2679,15 +2679,15 @@ xlog_recover_process_one_iunlink(
 	xfs_ino_t			ino;
 	int				error;
 
-	ino = XFS_AGINO_TO_INO(mp, agno, agino);
-	error = xfs_iget(mp, NULL, ino, 0, 0, &ip);
+	ino = XFS_AGINO_TO_INO(pag->pag_mount, pag->pag_agno, agino);
+	error = xfs_iget(pag->pag_mount, NULL, ino, 0, 0, &ip);
 	if (error)
 		goto fail;
 
 	/*
 	 * Get the on disk inode to find the next inode in the bucket.
 	 */
-	error = xfs_imap_to_bp(mp, NULL, &ip->i_imap, &ibp);
+	error = xfs_imap_to_bp(pag->pag_mount, NULL, &ip->i_imap, &ibp);
 	if (error)
 		goto fail_iput;
 	dip = xfs_buf_offset(ibp, ip->i_imap.im_boffset);
@@ -2714,7 +2714,7 @@ xlog_recover_process_one_iunlink(
 	 * Call xlog_recover_clear_agi_bucket() to perform a transaction to
 	 * clear the inode pointer in the bucket.
 	 */
-	xlog_recover_clear_agi_bucket(mp, agno, bucket);
+	xlog_recover_clear_agi_bucket(pag, bucket);
 	return NULLAGINO;
 }
 
@@ -2755,7 +2755,7 @@ xlog_recover_process_iunlinks(
 	int			error;
 
 	for_each_perag(mp, agno, pag) {
-		error = xfs_read_agi(mp, NULL, pag->pag_agno, &agibp);
+		error = xfs_read_agi(pag, NULL, &agibp);
 		if (error) {
 			/*
 			 * AGI is b0rked. Don't process it.
@@ -2780,8 +2780,8 @@ xlog_recover_process_iunlinks(
 		for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++) {
 			agino = be32_to_cpu(agi->agi_unlinked[bucket]);
 			while (agino != NULLAGINO) {
-				agino = xlog_recover_process_one_iunlink(mp,
-						pag->pag_agno, agino, bucket);
+				agino = xlog_recover_process_one_iunlink(pag,
+						agino, bucket);
 				cond_resched();
 			}
 		}
@@ -3313,7 +3313,8 @@ xlog_do_recover(
 	/* re-initialise in-core superblock and geometry structures */
 	mp->m_features |= xfs_sb_version_to_features(sbp);
 	xfs_reinit_percpu_counters(mp);
-	error = xfs_initialize_perag(mp, sbp->sb_agcount, &mp->m_maxagi);
+	error = xfs_initialize_perag(mp, sbp->sb_agcount, sbp->sb_dblocks,
+			&mp->m_maxagi);
 	if (error) {
 		xfs_warn(mp, "Failed post-recovery per-ag init: %d", error);
 		return error;

fs/xfs/xfs_mount.c

@@ -778,7 +778,8 @@ xfs_mountfs(
 	/*
 	 * Allocate and initialize the per-ag data.
 	 */
-	error = xfs_initialize_perag(mp, sbp->sb_agcount, &mp->m_maxagi);
+	error = xfs_initialize_perag(mp, sbp->sb_agcount, mp->m_sb.sb_dblocks,
+			&mp->m_maxagi);
 	if (error) {
 		xfs_warn(mp, "Failed per-ag init: %d", error);
 		goto out_free_dir;

fs/xfs/xfs_reflink.c

@@ -125,11 +125,10 @@
  * shared blocks.  If there are no shared extents, fbno and flen will
  * be set to NULLAGBLOCK and 0, respectively.
  */
-int
+static int
 xfs_reflink_find_shared(
-	struct xfs_mount	*mp,
+	struct xfs_perag	*pag,
 	struct xfs_trans	*tp,
-	xfs_agnumber_t		agno,
 	xfs_agblock_t		agbno,
 	xfs_extlen_t		aglen,
 	xfs_agblock_t		*fbno,
@@ -140,11 +139,11 @@ xfs_reflink_find_shared(
 	struct xfs_btree_cur	*cur;
 	int			error;
 
-	error = xfs_alloc_read_agf(mp, tp, agno, 0, &agbp);
+	error = xfs_alloc_read_agf(pag, tp, 0, &agbp);
 	if (error)
 		return error;
 
-	cur = xfs_refcountbt_init_cursor(mp, tp, agbp, agbp->b_pag);
+	cur = xfs_refcountbt_init_cursor(pag->pag_mount, tp, agbp, pag);
 
 	error = xfs_refcount_find_shared(cur, agbno, aglen, fbno, flen,
 			find_end_of_shared);
@@ -171,7 +170,8 @@ xfs_reflink_trim_around_shared(
 	struct xfs_bmbt_irec	*irec,
 	bool			*shared)
 {
-	xfs_agnumber_t		agno;
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_perag	*pag;
 	xfs_agblock_t		agbno;
 	xfs_extlen_t		aglen;
 	xfs_agblock_t		fbno;
@@ -186,12 +186,13 @@ xfs_reflink_trim_around_shared(
 
 	trace_xfs_reflink_trim_around_shared(ip, irec);
 
-	agno = XFS_FSB_TO_AGNO(ip->i_mount, irec->br_startblock);
-	agbno = XFS_FSB_TO_AGBNO(ip->i_mount, irec->br_startblock);
+	pag = xfs_perag_get(mp, XFS_FSB_TO_AGNO(mp, irec->br_startblock));
+	agbno = XFS_FSB_TO_AGBNO(mp, irec->br_startblock);
 	aglen = irec->br_blockcount;
 
-	error = xfs_reflink_find_shared(ip->i_mount, NULL, agno, agbno,
-			aglen, &fbno, &flen, true);
+	error = xfs_reflink_find_shared(pag, NULL, agbno, aglen, &fbno, &flen,
+			true);
+	xfs_perag_put(pag);
 	if (error)
 		return error;
 
@@ -1420,11 +1421,6 @@ xfs_reflink_inode_has_shared_extents(
 	struct xfs_bmbt_irec		got;
 	struct xfs_mount		*mp = ip->i_mount;
 	struct xfs_ifork		*ifp;
-	xfs_agnumber_t			agno;
-	xfs_agblock_t			agbno;
-	xfs_extlen_t			aglen;
-	xfs_agblock_t			rbno;
-	xfs_extlen_t			rlen;
 	struct xfs_iext_cursor		icur;
 	bool				found;
 	int				error;
@@ -1437,17 +1433,25 @@ xfs_reflink_inode_has_shared_extents(
 	*has_shared = false;
 	found = xfs_iext_lookup_extent(ip, ifp, 0, &icur, &got);
 	while (found) {
+		struct xfs_perag	*pag;
+		xfs_agblock_t		agbno;
+		xfs_extlen_t		aglen;
+		xfs_agblock_t		rbno;
+		xfs_extlen_t		rlen;
+
 		if (isnullstartblock(got.br_startblock) ||
 		    got.br_state != XFS_EXT_NORM)
 			goto next;
-		agno = XFS_FSB_TO_AGNO(mp, got.br_startblock);
+
+		pag = xfs_perag_get(mp, XFS_FSB_TO_AGNO(mp, got.br_startblock));
 		agbno = XFS_FSB_TO_AGBNO(mp, got.br_startblock);
 		aglen = got.br_blockcount;
-
-		error = xfs_reflink_find_shared(mp, tp, agno, agbno, aglen,
+		error = xfs_reflink_find_shared(pag, tp, agbno, aglen,
 				&rbno, &rlen, false);
+		xfs_perag_put(pag);
 		if (error)
 			return error;
+
 		/* Is there still a shared block here? */
 		if (rbno != NULLAGBLOCK) {
 			*has_shared = true;

fs/xfs/xfs_reflink.h

@@ -16,9 +16,6 @@ static inline bool xfs_is_cow_inode(struct xfs_inode *ip)
 	return xfs_is_reflink_inode(ip) || xfs_is_always_cow_inode(ip);
 }
 
-extern int xfs_reflink_find_shared(struct xfs_mount *mp, struct xfs_trans *tp,
-		xfs_agnumber_t agno, xfs_agblock_t agbno, xfs_extlen_t aglen,
-		xfs_agblock_t *fbno, xfs_extlen_t *flen, bool find_maximal);
 extern int xfs_reflink_trim_around_shared(struct xfs_inode *ip,
 		struct xfs_bmbt_irec *irec, bool *shared);
 int xfs_bmap_trim_cow(struct xfs_inode *ip, struct xfs_bmbt_irec *imap,