xfs: refactor and tablise growfs

index 830e2f6c064a..f5f2b71c2fde 100644
@@ -347,6 +347,18 @@ extern void xfs_buf_terminate(void);
 
 void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref);
 
+/*
+ * If the buffer is already on the LRU, do nothing. Otherwise set the buffer
+ * up with a reference count of 0 so it will be tossed from the cache when
+ * released.
+ */
+static inline void xfs_buf_oneshot(struct xfs_buf *bp)
+{
+	if (!list_empty(&bp->b_lru) || atomic_read(&bp->b_lru_ref) > 1)
+		return;
+	atomic_set(&bp->b_lru_ref, 0);
+}
+
 static inline int xfs_buf_ispinned(struct xfs_buf *bp)
 {
 	return atomic_read(&bp->b_pin_count);

index 523792768080..391d1938a6c8 100644
@@ -71,20 +71,344 @@ xfs_growfs_get_hdr_buf(
 	return bp;
 }
 
+/*
+ * Write new AG headers to disk. Non-transactional, but written
+ * synchronously so they are completed prior to the growfs transaction
+ * being logged.
+ */
+static int
+xfs_grow_ag_headers(
+	struct xfs_mount	*mp,
+	xfs_agnumber_t		agno,
+	xfs_extlen_t		agsize,
+	xfs_rfsblock_t		*nfree)
+{
+	struct xfs_agf		*agf;
+	struct xfs_agi		*agi;
+	struct xfs_agfl		*agfl;
+	__be32			*agfl_bno;
+	xfs_alloc_rec_t		*arec;
+	struct xfs_buf		*bp;
+	int			bucket;
+	xfs_extlen_t		tmpsize;
+	int			error = 0;
+
+	/*
+	 * AG freespace header block
+	 */
+	bp = xfs_growfs_get_hdr_buf(mp,
+			XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)),
+			XFS_FSS_TO_BB(mp, 1), 0,
+			&xfs_agf_buf_ops);
+	if (!bp) {
+		error = -ENOMEM;
+		goto out_error;
+	}
+
+	agf = XFS_BUF_TO_AGF(bp);
+	agf->agf_magicnum = cpu_to_be32(XFS_AGF_MAGIC);
+	agf->agf_versionnum = cpu_to_be32(XFS_AGF_VERSION);
+	agf->agf_seqno = cpu_to_be32(agno);
+	agf->agf_length = cpu_to_be32(agsize);
+	agf->agf_roots[XFS_BTNUM_BNOi] = cpu_to_be32(XFS_BNO_BLOCK(mp));
+	agf->agf_roots[XFS_BTNUM_CNTi] = cpu_to_be32(XFS_CNT_BLOCK(mp));
+	agf->agf_levels[XFS_BTNUM_BNOi] = cpu_to_be32(1);
+	agf->agf_levels[XFS_BTNUM_CNTi] = cpu_to_be32(1);
+	if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
+		agf->agf_roots[XFS_BTNUM_RMAPi] =
+					cpu_to_be32(XFS_RMAP_BLOCK(mp));
+		agf->agf_levels[XFS_BTNUM_RMAPi] = cpu_to_be32(1);
+		agf->agf_rmap_blocks = cpu_to_be32(1);
+	}
+
+	agf->agf_flfirst = cpu_to_be32(1);
+	agf->agf_fllast = 0;
+	agf->agf_flcount = 0;
+	tmpsize = agsize - mp->m_ag_prealloc_blocks;
+	agf->agf_freeblks = cpu_to_be32(tmpsize);
+	agf->agf_longest = cpu_to_be32(tmpsize);
+	if (xfs_sb_version_hascrc(&mp->m_sb))
+		uuid_copy(&agf->agf_uuid, &mp->m_sb.sb_meta_uuid);
+	if (xfs_sb_version_hasreflink(&mp->m_sb)) {
+		agf->agf_refcount_root = cpu_to_be32(
+				xfs_refc_block(mp));
+		agf->agf_refcount_level = cpu_to_be32(1);
+		agf->agf_refcount_blocks = cpu_to_be32(1);
+	}
+
+	error = xfs_bwrite(bp);
+	xfs_buf_relse(bp);
+	if (error)
+		goto out_error;
+
+	/*
+	 * AG freelist header block
+	 */
+	bp = xfs_growfs_get_hdr_buf(mp,
+			XFS_AG_DADDR(mp, agno, XFS_AGFL_DADDR(mp)),
+			XFS_FSS_TO_BB(mp, 1), 0,
+			&xfs_agfl_buf_ops);
+	if (!bp) {
+		error = -ENOMEM;
+		goto out_error;
+	}
+
+	agfl = XFS_BUF_TO_AGFL(bp);
+	if (xfs_sb_version_hascrc(&mp->m_sb)) {
+		agfl->agfl_magicnum = cpu_to_be32(XFS_AGFL_MAGIC);
+		agfl->agfl_seqno = cpu_to_be32(agno);
+		uuid_copy(&agfl->agfl_uuid, &mp->m_sb.sb_meta_uuid);
+	}
+
+	agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, bp);
+	for (bucket = 0; bucket < xfs_agfl_size(mp); bucket++)
+		agfl_bno[bucket] = cpu_to_be32(NULLAGBLOCK);
+
+	error = xfs_bwrite(bp);
+	xfs_buf_relse(bp);
+	if (error)
+		goto out_error;
+
+	/*
+	 * AG inode header block
+	 */
+	bp = xfs_growfs_get_hdr_buf(mp,
+			XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
+			XFS_FSS_TO_BB(mp, 1), 0,
+			&xfs_agi_buf_ops);
+	if (!bp) {
+		error = -ENOMEM;
+		goto out_error;
+	}
+
+	agi = XFS_BUF_TO_AGI(bp);
+	agi->agi_magicnum = cpu_to_be32(XFS_AGI_MAGIC);
+	agi->agi_versionnum = cpu_to_be32(XFS_AGI_VERSION);
+	agi->agi_seqno = cpu_to_be32(agno);
+	agi->agi_length = cpu_to_be32(agsize);
+	agi->agi_count = 0;
+	agi->agi_root = cpu_to_be32(XFS_IBT_BLOCK(mp));
+	agi->agi_level = cpu_to_be32(1);
+	agi->agi_freecount = 0;
+	agi->agi_newino = cpu_to_be32(NULLAGINO);
+	agi->agi_dirino = cpu_to_be32(NULLAGINO);
+	if (xfs_sb_version_hascrc(&mp->m_sb))
+		uuid_copy(&agi->agi_uuid, &mp->m_sb.sb_meta_uuid);
+	if (xfs_sb_version_hasfinobt(&mp->m_sb)) {
+		agi->agi_free_root = cpu_to_be32(XFS_FIBT_BLOCK(mp));
+		agi->agi_free_level = cpu_to_be32(1);
+	}
+	for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
+		agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
+
+	error = xfs_bwrite(bp);
+	xfs_buf_relse(bp);
+	if (error)
+		goto out_error;
+
+	/*
+	 * BNO btree root block
+	 */
+	bp = xfs_growfs_get_hdr_buf(mp,
+			XFS_AGB_TO_DADDR(mp, agno, XFS_BNO_BLOCK(mp)),
+			BTOBB(mp->m_sb.sb_blocksize), 0,
+			&xfs_allocbt_buf_ops);
+
+	if (!bp) {
+		error = -ENOMEM;
+		goto out_error;
+	}
+
+	xfs_btree_init_block(mp, bp, XFS_BTNUM_BNO, 0, 1, agno, 0);
+
+	arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
+	arec->ar_startblock = cpu_to_be32(mp->m_ag_prealloc_blocks);
+	arec->ar_blockcount = cpu_to_be32(
+		agsize - be32_to_cpu(arec->ar_startblock));
+
+	error = xfs_bwrite(bp);
+	xfs_buf_relse(bp);
+	if (error)
+		goto out_error;
+
+	/*
+	 * CNT btree root block
+	 */
+	bp = xfs_growfs_get_hdr_buf(mp,
+			XFS_AGB_TO_DADDR(mp, agno, XFS_CNT_BLOCK(mp)),
+			BTOBB(mp->m_sb.sb_blocksize), 0,
+			&xfs_allocbt_buf_ops);
+	if (!bp) {
+		error = -ENOMEM;
+		goto out_error;
+	}
+
+	xfs_btree_init_block(mp, bp, XFS_BTNUM_CNT, 0, 1, agno, 0);
+
+	arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
+	arec->ar_startblock = cpu_to_be32(mp->m_ag_prealloc_blocks);
+	arec->ar_blockcount = cpu_to_be32(
+		agsize - be32_to_cpu(arec->ar_startblock));
+	*nfree += be32_to_cpu(arec->ar_blockcount);
+
+	error = xfs_bwrite(bp);
+	xfs_buf_relse(bp);
+	if (error)
+		goto out_error;
+
+	/* RMAP btree root block */
+	if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
+		struct xfs_rmap_rec	*rrec;
+		struct xfs_btree_block	*block;
+
+		bp = xfs_growfs_get_hdr_buf(mp,
+			XFS_AGB_TO_DADDR(mp, agno, XFS_RMAP_BLOCK(mp)),
+			BTOBB(mp->m_sb.sb_blocksize), 0,
+			&xfs_rmapbt_buf_ops);
+		if (!bp) {
+			error = -ENOMEM;
+			goto out_error;
+		}
+
+		xfs_btree_init_block(mp, bp, XFS_BTNUM_RMAP, 0, 0,
+					agno, 0);
+		block = XFS_BUF_TO_BLOCK(bp);
+
+
+		/*
+		 * mark the AG header regions as static metadata The BNO
+		 * btree block is the first block after the headers, so
+		 * it's location defines the size of region the static
+		 * metadata consumes.
+		 *
+		 * Note: unlike mkfs, we never have to account for log
+		 * space when growing the data regions
+		 */
+		rrec = XFS_RMAP_REC_ADDR(block, 1);
+		rrec->rm_startblock = 0;
+		rrec->rm_blockcount = cpu_to_be32(XFS_BNO_BLOCK(mp));
+		rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_FS);
+		rrec->rm_offset = 0;
+		be16_add_cpu(&block->bb_numrecs, 1);
+
+		/* account freespace btree root blocks */
+		rrec = XFS_RMAP_REC_ADDR(block, 2);
+		rrec->rm_startblock = cpu_to_be32(XFS_BNO_BLOCK(mp));
+		rrec->rm_blockcount = cpu_to_be32(2);
+		rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
+		rrec->rm_offset = 0;
+		be16_add_cpu(&block->bb_numrecs, 1);
+
+		/* account inode btree root blocks */
+		rrec = XFS_RMAP_REC_ADDR(block, 3);
+		rrec->rm_startblock = cpu_to_be32(XFS_IBT_BLOCK(mp));
+		rrec->rm_blockcount = cpu_to_be32(XFS_RMAP_BLOCK(mp) -
+						XFS_IBT_BLOCK(mp));
+		rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_INOBT);
+		rrec->rm_offset = 0;
+		be16_add_cpu(&block->bb_numrecs, 1);
+
+		/* account for rmap btree root */
+		rrec = XFS_RMAP_REC_ADDR(block, 4);
+		rrec->rm_startblock = cpu_to_be32(XFS_RMAP_BLOCK(mp));
+		rrec->rm_blockcount = cpu_to_be32(1);
+		rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
+		rrec->rm_offset = 0;
+		be16_add_cpu(&block->bb_numrecs, 1);
+
+		/* account for refc btree root */
+		if (xfs_sb_version_hasreflink(&mp->m_sb)) {
+			rrec = XFS_RMAP_REC_ADDR(block, 5);
+			rrec->rm_startblock = cpu_to_be32(xfs_refc_block(mp));
+			rrec->rm_blockcount = cpu_to_be32(1);
+			rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_REFC);
+			rrec->rm_offset = 0;
+			be16_add_cpu(&block->bb_numrecs, 1);
+		}
+
+		error = xfs_bwrite(bp);
+		xfs_buf_relse(bp);
+		if (error)
+			goto out_error;
+	}
+
+	/*
+	 * INO btree root block
+	 */
+	bp = xfs_growfs_get_hdr_buf(mp,
+			XFS_AGB_TO_DADDR(mp, agno, XFS_IBT_BLOCK(mp)),
+			BTOBB(mp->m_sb.sb_blocksize), 0,
+			&xfs_inobt_buf_ops);
+	if (!bp) {
+		error = -ENOMEM;
+		goto out_error;
+	}
+
+	xfs_btree_init_block(mp, bp, XFS_BTNUM_INO , 0, 0, agno, 0);
+
+	error = xfs_bwrite(bp);
+	xfs_buf_relse(bp);
+	if (error)
+		goto out_error;
+
+	/*
+	 * FINO btree root block
+	 */
+	if (xfs_sb_version_hasfinobt(&mp->m_sb)) {
+		bp = xfs_growfs_get_hdr_buf(mp,
+			XFS_AGB_TO_DADDR(mp, agno, XFS_FIBT_BLOCK(mp)),
+			BTOBB(mp->m_sb.sb_blocksize), 0,
+			&xfs_inobt_buf_ops);
+		if (!bp) {
+			error = -ENOMEM;
+			goto out_error;
+		}
+
+		xfs_btree_init_block(mp, bp, XFS_BTNUM_FINO,
+					     0, 0, agno, 0);
+
+		error = xfs_bwrite(bp);
+		xfs_buf_relse(bp);
+		if (error)
+			goto out_error;
+	}
+
+	/*
+	 * refcount btree root block
+	 */
+	if (xfs_sb_version_hasreflink(&mp->m_sb)) {
+		bp = xfs_growfs_get_hdr_buf(mp,
+			XFS_AGB_TO_DADDR(mp, agno, xfs_refc_block(mp)),
+			BTOBB(mp->m_sb.sb_blocksize), 0,
+			&xfs_refcountbt_buf_ops);
+		if (!bp) {
+			error = -ENOMEM;
+			goto out_error;
+		}
+
+		xfs_btree_init_block(mp, bp, XFS_BTNUM_REFC,
+				     0, 0, agno, 0);
+
+		error = xfs_bwrite(bp);
+		xfs_buf_relse(bp);
+		if (error)
+			goto out_error;
+	}
+
+out_error:
+	return error;
+}
+
 static int
 xfs_growfs_data_private(
 	xfs_mount_t		*mp,		/* mount point for filesystem */
 	xfs_growfs_data_t	*in)		/* growfs data input struct */
 {
 	xfs_agf_t		*agf;
-	struct xfs_agfl		*agfl;
 	xfs_agi_t		*agi;
 	xfs_agnumber_t		agno;
 	xfs_extlen_t		agsize;
-	xfs_extlen_t		tmpsize;
-	xfs_alloc_rec_t		*arec;
 	xfs_buf_t		*bp;
-	int			bucket;
 	int			dpct;
 	int			error, saved_error = 0;
 	xfs_agnumber_t		nagcount;

@@ -141,318 +465,19 @@ xfs_growfs_data_private(
 	 */
 	nfree = 0;
 	for (agno = nagcount - 1; agno >= oagcount; agno--, new -= agsize) {
-		__be32	*agfl_bno;
-
-		/*
-		 * AG freespace header block
-		 */
-		bp = xfs_growfs_get_hdr_buf(mp,
-				XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)),
-				XFS_FSS_TO_BB(mp, 1), 0,
-				&xfs_agf_buf_ops);
-		if (!bp) {
-			error = -ENOMEM;
-			goto error0;
-		}
 
-		agf = XFS_BUF_TO_AGF(bp);
-		agf->agf_magicnum = cpu_to_be32(XFS_AGF_MAGIC);
-		agf->agf_versionnum = cpu_to_be32(XFS_AGF_VERSION);
-		agf->agf_seqno = cpu_to_be32(agno);
 		if (agno == nagcount - 1)
-			agsize =
-				nb -
+			agsize = nb -
 				(agno * (xfs_rfsblock_t)mp->m_sb.sb_agblocks);
 		else
 			agsize = mp->m_sb.sb_agblocks;
-		agf->agf_length = cpu_to_be32(agsize);
-		agf->agf_roots[XFS_BTNUM_BNOi] = cpu_to_be32(XFS_BNO_BLOCK(mp));
-		agf->agf_roots[XFS_BTNUM_CNTi] = cpu_to_be32(XFS_CNT_BLOCK(mp));
-		agf->agf_levels[XFS_BTNUM_BNOi] = cpu_to_be32(1);
-		agf->agf_levels[XFS_BTNUM_CNTi] = cpu_to_be32(1);
-		if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
-			agf->agf_roots[XFS_BTNUM_RMAPi] =
-						cpu_to_be32(XFS_RMAP_BLOCK(mp));
-			agf->agf_levels[XFS_BTNUM_RMAPi] = cpu_to_be32(1);
-			agf->agf_rmap_blocks = cpu_to_be32(1);
-		}
-
-		agf->agf_flfirst = cpu_to_be32(1);
-		agf->agf_fllast = 0;
-		agf->agf_flcount = 0;
-		tmpsize = agsize - mp->m_ag_prealloc_blocks;
-		agf->agf_freeblks = cpu_to_be32(tmpsize);
-		agf->agf_longest = cpu_to_be32(tmpsize);
-		if (xfs_sb_version_hascrc(&mp->m_sb))
-			uuid_copy(&agf->agf_uuid, &mp->m_sb.sb_meta_uuid);
-		if (xfs_sb_version_hasreflink(&mp->m_sb)) {
-			agf->agf_refcount_root = cpu_to_be32(
-					xfs_refc_block(mp));
-			agf->agf_refcount_level = cpu_to_be32(1);
-			agf->agf_refcount_blocks = cpu_to_be32(1);
-		}
-
-		error = xfs_bwrite(bp);
-		xfs_buf_relse(bp);
-		if (error)
-			goto error0;
-
-		/*
-		 * AG freelist header block
-		 */
-		bp = xfs_growfs_get_hdr_buf(mp,
-				XFS_AG_DADDR(mp, agno, XFS_AGFL_DADDR(mp)),
-				XFS_FSS_TO_BB(mp, 1), 0,
-				&xfs_agfl_buf_ops);
-		if (!bp) {
-			error = -ENOMEM;
-			goto error0;
-		}
-
-		agfl = XFS_BUF_TO_AGFL(bp);
-		if (xfs_sb_version_hascrc(&mp->m_sb)) {
-			agfl->agfl_magicnum = cpu_to_be32(XFS_AGFL_MAGIC);
-			agfl->agfl_seqno = cpu_to_be32(agno);
-			uuid_copy(&agfl->agfl_uuid, &mp->m_sb.sb_meta_uuid);
-		}
-
-		agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, bp);
-		for (bucket = 0; bucket < xfs_agfl_size(mp); bucket++)
-			agfl_bno[bucket] = cpu_to_be32(NULLAGBLOCK);
 
-		error = xfs_bwrite(bp);
-		xfs_buf_relse(bp);
+		error = xfs_grow_ag_headers(mp, agno, agsize, &nfree);
 		if (error)
 			goto error0;
-
-		/*
-		 * AG inode header block
-		 */
-		bp = xfs_growfs_get_hdr_buf(mp,
-				XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
-				XFS_FSS_TO_BB(mp, 1), 0,
-				&xfs_agi_buf_ops);
-		if (!bp) {
-			error = -ENOMEM;
-			goto error0;
-		}
-
-		agi = XFS_BUF_TO_AGI(bp);
-		agi->agi_magicnum = cpu_to_be32(XFS_AGI_MAGIC);
-		agi->agi_versionnum = cpu_to_be32(XFS_AGI_VERSION);
-		agi->agi_seqno = cpu_to_be32(agno);
-		agi->agi_length = cpu_to_be32(agsize);
-		agi->agi_count = 0;
-		agi->agi_root = cpu_to_be32(XFS_IBT_BLOCK(mp));
-		agi->agi_level = cpu_to_be32(1);
-		agi->agi_freecount = 0;
-		agi->agi_newino = cpu_to_be32(NULLAGINO);
-		agi->agi_dirino = cpu_to_be32(NULLAGINO);
-		if (xfs_sb_version_hascrc(&mp->m_sb))
-			uuid_copy(&agi->agi_uuid, &mp->m_sb.sb_meta_uuid);
-		if (xfs_sb_version_hasfinobt(&mp->m_sb)) {
-			agi->agi_free_root = cpu_to_be32(XFS_FIBT_BLOCK(mp));
-			agi->agi_free_level = cpu_to_be32(1);
-		}
-		for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
-			agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
-
-		error = xfs_bwrite(bp);
-		xfs_buf_relse(bp);
-		if (error)
-			goto error0;
-
-		/*
-		 * BNO btree root block
-		 */
-		bp = xfs_growfs_get_hdr_buf(mp,
-				XFS_AGB_TO_DADDR(mp, agno, XFS_BNO_BLOCK(mp)),
-				BTOBB(mp->m_sb.sb_blocksize), 0,
-				&xfs_allocbt_buf_ops);
-
-		if (!bp) {
-			error = -ENOMEM;
-			goto error0;
-		}
-
-		xfs_btree_init_block(mp, bp, XFS_BTNUM_BNO, 0, 1, agno, 0);
-
-		arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
-		arec->ar_startblock = cpu_to_be32(mp->m_ag_prealloc_blocks);
-		arec->ar_blockcount = cpu_to_be32(
-			agsize - be32_to_cpu(arec->ar_startblock));
-
-		error = xfs_bwrite(bp);
-		xfs_buf_relse(bp);
-		if (error)
-			goto error0;
-
-		/*
-		 * CNT btree root block
-		 */
-		bp = xfs_growfs_get_hdr_buf(mp,
-				XFS_AGB_TO_DADDR(mp, agno, XFS_CNT_BLOCK(mp)),
-				BTOBB(mp->m_sb.sb_blocksize), 0,
-				&xfs_allocbt_buf_ops);
-		if (!bp) {
-			error = -ENOMEM;
-			goto error0;
-		}
-
-		xfs_btree_init_block(mp, bp, XFS_BTNUM_CNT, 0, 1, agno, 0);
-
-		arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
-		arec->ar_startblock = cpu_to_be32(mp->m_ag_prealloc_blocks);
-		arec->ar_blockcount = cpu_to_be32(
-			agsize - be32_to_cpu(arec->ar_startblock));
-		nfree += be32_to_cpu(arec->ar_blockcount);
-
-		error = xfs_bwrite(bp);
-		xfs_buf_relse(bp);
-		if (error)
-			goto error0;
-
-		/* RMAP btree root block */
-		if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
-			struct xfs_rmap_rec	*rrec;
-			struct xfs_btree_block	*block;
-
-			bp = xfs_growfs_get_hdr_buf(mp,
-				XFS_AGB_TO_DADDR(mp, agno, XFS_RMAP_BLOCK(mp)),
-				BTOBB(mp->m_sb.sb_blocksize), 0,
-				&xfs_rmapbt_buf_ops);
-			if (!bp) {
-				error = -ENOMEM;
-				goto error0;
-			}
-
-			xfs_btree_init_block(mp, bp, XFS_BTNUM_RMAP, 0, 0,
-						agno, 0);
-			block = XFS_BUF_TO_BLOCK(bp);
-
-
-			/*
-			 * mark the AG header regions as static metadata The BNO
-			 * btree block is the first block after the headers, so
-			 * it's location defines the size of region the static
-			 * metadata consumes.
-			 *
-			 * Note: unlike mkfs, we never have to account for log
-			 * space when growing the data regions
-			 */
-			rrec = XFS_RMAP_REC_ADDR(block, 1);
-			rrec->rm_startblock = 0;
-			rrec->rm_blockcount = cpu_to_be32(XFS_BNO_BLOCK(mp));
-			rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_FS);
-			rrec->rm_offset = 0;
-			be16_add_cpu(&block->bb_numrecs, 1);
-
-			/* account freespace btree root blocks */
-			rrec = XFS_RMAP_REC_ADDR(block, 2);
-			rrec->rm_startblock = cpu_to_be32(XFS_BNO_BLOCK(mp));
-			rrec->rm_blockcount = cpu_to_be32(2);
-			rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
-			rrec->rm_offset = 0;
-			be16_add_cpu(&block->bb_numrecs, 1);
-
-			/* account inode btree root blocks */
-			rrec = XFS_RMAP_REC_ADDR(block, 3);
-			rrec->rm_startblock = cpu_to_be32(XFS_IBT_BLOCK(mp));
-			rrec->rm_blockcount = cpu_to_be32(XFS_RMAP_BLOCK(mp) -
-							XFS_IBT_BLOCK(mp));
-			rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_INOBT);
-			rrec->rm_offset = 0;
-			be16_add_cpu(&block->bb_numrecs, 1);
-
-			/* account for rmap btree root */
-			rrec = XFS_RMAP_REC_ADDR(block, 4);
-			rrec->rm_startblock = cpu_to_be32(XFS_RMAP_BLOCK(mp));
-			rrec->rm_blockcount = cpu_to_be32(1);
-			rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
-			rrec->rm_offset = 0;
-			be16_add_cpu(&block->bb_numrecs, 1);
-
-			/* account for refc btree root */
-			if (xfs_sb_version_hasreflink(&mp->m_sb)) {
-				rrec = XFS_RMAP_REC_ADDR(block, 5);
-				rrec->rm_startblock = cpu_to_be32(
-						xfs_refc_block(mp));
-				rrec->rm_blockcount = cpu_to_be32(1);
-				rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_REFC);
-				rrec->rm_offset = 0;
-				be16_add_cpu(&block->bb_numrecs, 1);
-			}
-
-			error = xfs_bwrite(bp);
-			xfs_buf_relse(bp);
-			if (error)
-				goto error0;
-		}
-
-		/*
-		 * INO btree root block
-		 */
-		bp = xfs_growfs_get_hdr_buf(mp,
-				XFS_AGB_TO_DADDR(mp, agno, XFS_IBT_BLOCK(mp)),
-				BTOBB(mp->m_sb.sb_blocksize), 0,
-				&xfs_inobt_buf_ops);
-		if (!bp) {
-			error = -ENOMEM;
-			goto error0;
-		}
-
-		xfs_btree_init_block(mp, bp, XFS_BTNUM_INO , 0, 0, agno, 0);
-
-		error = xfs_bwrite(bp);
-		xfs_buf_relse(bp);
-		if (error)
-			goto error0;
-
-		/*
-		 * FINO btree root block
-		 */
-		if (xfs_sb_version_hasfinobt(&mp->m_sb)) {
-			bp = xfs_growfs_get_hdr_buf(mp,
-				XFS_AGB_TO_DADDR(mp, agno, XFS_FIBT_BLOCK(mp)),
-				BTOBB(mp->m_sb.sb_blocksize), 0,
-				&xfs_inobt_buf_ops);
-			if (!bp) {
-				error = -ENOMEM;
-				goto error0;
-			}
-
-			xfs_btree_init_block(mp, bp, XFS_BTNUM_FINO,
-						     0, 0, agno, 0);
-
-			error = xfs_bwrite(bp);
-			xfs_buf_relse(bp);
-			if (error)
-				goto error0;
-		}
-
-		/*
-		 * refcount btree root block
-		 */
-		if (xfs_sb_version_hasreflink(&mp->m_sb)) {
-			bp = xfs_growfs_get_hdr_buf(mp,
-				XFS_AGB_TO_DADDR(mp, agno, xfs_refc_block(mp)),
-				BTOBB(mp->m_sb.sb_blocksize), 0,
-				&xfs_refcountbt_buf_ops);
-			if (!bp) {
-				error = -ENOMEM;
-				goto error0;
-			}
-
-			xfs_btree_init_block(mp, bp, XFS_BTNUM_REFC,
-					     0, 0, agno, 0);
-
-			error = xfs_bwrite(bp);
-			xfs_buf_relse(bp);
-			if (error)
-				goto error0;
-		}
 	}
 	xfs_trans_agblocks_delta(tp, nfree);
+
 	/*
 	 * There are new blocks in the old last a.g.
 	 */

index 391d1938a6c8..4b560caaf397 100644
@@ -81,7 +81,8 @@ xfs_grow_ag_headers(
 	struct xfs_mount	*mp,
 	xfs_agnumber_t		agno,
 	xfs_extlen_t		agsize,
-	xfs_rfsblock_t		*nfree)
+	xfs_rfsblock_t		*nfree,
+	struct list_head	*buffer_list)
 {
 	struct xfs_agf		*agf;
 	struct xfs_agi		*agi;

@@ -135,11 +136,8 @@ xfs_grow_ag_headers(
 		agf->agf_refcount_level = cpu_to_be32(1);
 		agf->agf_refcount_blocks = cpu_to_be32(1);
 	}
-
-	error = xfs_bwrite(bp);
+	xfs_buf_delwri_queue(bp, buffer_list);
 	xfs_buf_relse(bp);
-	if (error)
-		goto out_error;
 
 	/*
 	 * AG freelist header block

@@ -164,10 +162,8 @@ xfs_grow_ag_headers(
 	for (bucket = 0; bucket < xfs_agfl_size(mp); bucket++)
 		agfl_bno[bucket] = cpu_to_be32(NULLAGBLOCK);
 
-	error = xfs_bwrite(bp);
+	xfs_buf_delwri_queue(bp, buffer_list);
 	xfs_buf_relse(bp);
-	if (error)
-		goto out_error;
 
 	/*
 	 * AG inode header block

@@ -201,10 +197,8 @@ xfs_grow_ag_headers(
 	for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
 		agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
 
-	error = xfs_bwrite(bp);
+	xfs_buf_delwri_queue(bp, buffer_list);
 	xfs_buf_relse(bp);
-	if (error)
-		goto out_error;
 
 	/*
 	 * BNO btree root block

@@ -226,10 +220,8 @@ xfs_grow_ag_headers(
 	arec->ar_blockcount = cpu_to_be32(
 		agsize - be32_to_cpu(arec->ar_startblock));
 
-	error = xfs_bwrite(bp);
+	xfs_buf_delwri_queue(bp, buffer_list);
 	xfs_buf_relse(bp);
-	if (error)
-		goto out_error;
 
 	/*
 	 * CNT btree root block

@@ -251,10 +243,8 @@ xfs_grow_ag_headers(
 		agsize - be32_to_cpu(arec->ar_startblock));
 	*nfree += be32_to_cpu(arec->ar_blockcount);
 
-	error = xfs_bwrite(bp);
+	xfs_buf_delwri_queue(bp, buffer_list);
 	xfs_buf_relse(bp);
-	if (error)
-		goto out_error;
 
 	/* RMAP btree root block */
 	if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {

@@ -326,10 +316,8 @@ xfs_grow_ag_headers(
 			be16_add_cpu(&block->bb_numrecs, 1);
 		}
 
-		error = xfs_bwrite(bp);
+		xfs_buf_delwri_queue(bp, buffer_list);
 		xfs_buf_relse(bp);
-		if (error)
-			goto out_error;
 	}
 
 	/*

@@ -345,11 +333,8 @@ xfs_grow_ag_headers(
 	}
 
 	xfs_btree_init_block(mp, bp, XFS_BTNUM_INO , 0, 0, agno, 0);
-
-	error = xfs_bwrite(bp);
+	xfs_buf_delwri_queue(bp, buffer_list);
 	xfs_buf_relse(bp);
-	if (error)
-		goto out_error;
 
 	/*
 	 * FINO btree root block

@@ -364,13 +349,9 @@ xfs_grow_ag_headers(
 			goto out_error;
 		}
 
-		xfs_btree_init_block(mp, bp, XFS_BTNUM_FINO,
-					     0, 0, agno, 0);
-
-		error = xfs_bwrite(bp);
+		xfs_btree_init_block(mp, bp, XFS_BTNUM_FINO, 0, 0, agno, 0);
+		xfs_buf_delwri_queue(bp, buffer_list);
 		xfs_buf_relse(bp);
-		if (error)
-			goto out_error;
 	}
 
 	/*

@@ -386,13 +367,9 @@ xfs_grow_ag_headers(
 			goto out_error;
 		}
 
-		xfs_btree_init_block(mp, bp, XFS_BTNUM_REFC,
-				     0, 0, agno, 0);
-
-		error = xfs_bwrite(bp);
+		xfs_btree_init_block(mp, bp, XFS_BTNUM_REFC, 0, 0, agno, 0);
+		xfs_buf_delwri_queue(bp, buffer_list);
 		xfs_buf_relse(bp);
-		if (error)
-			goto out_error;
 	}
 
 out_error:

@@ -419,6 +396,7 @@ xfs_growfs_data_private(
 	xfs_agnumber_t		oagcount;
 	int			pct;
 	xfs_trans_t		*tp;
+	LIST_HEAD		(buffer_list);
 
 	nb = in->newblocks;
 	pct = in->imaxpct;

@@ -459,9 +437,16 @@ xfs_growfs_data_private(
 		return error;
 
 	/*
-	 * Write new AG headers to disk. Non-transactional, but written
-	 * synchronously so they are completed prior to the growfs transaction
-	 * being logged.
+	 * Write new AG headers to disk. Non-transactional, but need to be
+	 * written and completed prior to the growfs transaction being logged.
+	 * To do this, we use a delayed write buffer list and wait for
+	 * submission and IO completion of the list as a whole. This allows the
+	 * IO subsystem to merge all the AG headers in a single AG into a single
+	 * IO and hide most of the latency of the IO from us.
+	 *
+	 * This also means that if we get an error whilst building the buffer
+	 * list to write, we can cancel the entire list without having written
+	 * anything.
 	 */
 	nfree = 0;
 	for (agno = nagcount - 1; agno >= oagcount; agno--, new -= agsize) {

@@ -472,10 +457,17 @@ xfs_growfs_data_private(
 		else
 			agsize = mp->m_sb.sb_agblocks;
 
-		error = xfs_grow_ag_headers(mp, agno, agsize, &nfree);
-		if (error)
+		error = xfs_grow_ag_headers(mp, agno, agsize, &nfree,
+					    &buffer_list);
+		if (error) {
+			xfs_buf_delwri_cancel(&buffer_list);
 			goto error0;
+		}
 	}
+	error = xfs_buf_delwri_submit(&buffer_list);
+	if (error)
+		goto error0;
+
 	xfs_trans_agblocks_delta(tp, nfree);
 
 	/*

index 4b560caaf397..ec3c51ee8134 100644
@@ -71,46 +71,140 @@ xfs_growfs_get_hdr_buf(
 	return bp;
 }
 
+struct aghdr_init_data {
+	/* per ag data */
+	xfs_agnumber_t		agno;		/* ag to init */
+	xfs_extlen_t		agsize;		/* new AG size */
+	struct list_head	buffer_list;	/* buffer writeback list */
+	xfs_rfsblock_t		nfree;		/* cumulative new free space */
+
+	/* per header data */
+	xfs_daddr_t		daddr;		/* header location */
+	size_t			numblks;	/* size of header */
+	xfs_btnum_t		type;		/* type of btree root block */
+};
+
 /*
- * Write new AG headers to disk. Non-transactional, but written
- * synchronously so they are completed prior to the growfs transaction
- * being logged.
+ * Generic btree root block init function
  */
-static int
-xfs_grow_ag_headers(
+static void
+xfs_btroot_init(
 	struct xfs_mount	*mp,
-	xfs_agnumber_t		agno,
-	xfs_extlen_t		agsize,
-	xfs_rfsblock_t		*nfree,
-	struct list_head	*buffer_list)
+	struct xfs_buf		*bp,
+	struct aghdr_init_data	*id)
 {
-	struct xfs_agf		*agf;
-	struct xfs_agi		*agi;
-	struct xfs_agfl		*agfl;
-	__be32			*agfl_bno;
-	xfs_alloc_rec_t		*arec;
-	struct xfs_buf		*bp;
-	int			bucket;
-	xfs_extlen_t		tmpsize;
-	int			error = 0;
+	xfs_btree_init_block(mp, bp, id->type, 0, 0, id->agno, 0);
+}
+
+/*
+ * Alloc btree root block init functions
+ */
+static void
+xfs_bnoroot_init(
+	struct xfs_mount	*mp,
+	struct xfs_buf		*bp,
+	struct aghdr_init_data	*id)
+{
+	struct xfs_alloc_rec	*arec;
+
+	xfs_btree_init_block(mp, bp, XFS_BTNUM_BNO, 0, 1, id->agno, 0);
+	arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
+	arec->ar_startblock = cpu_to_be32(mp->m_ag_prealloc_blocks);
+	arec->ar_blockcount = cpu_to_be32(id->agsize -
+					  be32_to_cpu(arec->ar_startblock));
+}
+
+static void
+xfs_cntroot_init(
+	struct xfs_mount	*mp,
+	struct xfs_buf		*bp,
+	struct aghdr_init_data	*id)
+{
+	struct xfs_alloc_rec	*arec;
+
+	xfs_btree_init_block(mp, bp, XFS_BTNUM_CNT, 0, 1, id->agno, 0);
+	arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
+	arec->ar_startblock = cpu_to_be32(mp->m_ag_prealloc_blocks);
+	arec->ar_blockcount = cpu_to_be32(id->agsize -
+					  be32_to_cpu(arec->ar_startblock));
+}
+
+/*
+ * Reverse map root block init
+ */
+static void
+xfs_rmaproot_init(
+	struct xfs_mount	*mp,
+	struct xfs_buf		*bp,
+	struct aghdr_init_data	*id)
+{
+	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
+	struct xfs_rmap_rec	*rrec;
+
+	xfs_btree_init_block(mp, bp, XFS_BTNUM_RMAP, 0, 4, id->agno, 0);
 
 	/*
-	 * AG freespace header block
+	 * mark the AG header regions as static metadata The BNO
+	 * btree block is the first block after the headers, so
+	 * it's location defines the size of region the static
+	 * metadata consumes.
+	 *
+	 * Note: unlike mkfs, we never have to account for log
+	 * space when growing the data regions
 	 */
-	bp = xfs_growfs_get_hdr_buf(mp,
-			XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)),
-			XFS_FSS_TO_BB(mp, 1), 0,
-			&xfs_agf_buf_ops);
-	if (!bp) {
-		error = -ENOMEM;
-		goto out_error;
+	rrec = XFS_RMAP_REC_ADDR(block, 1);
+	rrec->rm_startblock = 0;
+	rrec->rm_blockcount = cpu_to_be32(XFS_BNO_BLOCK(mp));
+	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_FS);
+	rrec->rm_offset = 0;
+
+	/* account freespace btree root blocks */
+	rrec = XFS_RMAP_REC_ADDR(block, 2);
+	rrec->rm_startblock = cpu_to_be32(XFS_BNO_BLOCK(mp));
+	rrec->rm_blockcount = cpu_to_be32(2);
+	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
+	rrec->rm_offset = 0;
+
+	/* account inode btree root blocks */
+	rrec = XFS_RMAP_REC_ADDR(block, 3);
+	rrec->rm_startblock = cpu_to_be32(XFS_IBT_BLOCK(mp));
+	rrec->rm_blockcount = cpu_to_be32(XFS_RMAP_BLOCK(mp) -
+					  XFS_IBT_BLOCK(mp));
+	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_INOBT);
+	rrec->rm_offset = 0;
+
+	/* account for rmap btree root */
+	rrec = XFS_RMAP_REC_ADDR(block, 4);
+	rrec->rm_startblock = cpu_to_be32(XFS_RMAP_BLOCK(mp));
+	rrec->rm_blockcount = cpu_to_be32(1);
+	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
+	rrec->rm_offset = 0;
+
+	/* account for refc btree root */
+	if (xfs_sb_version_hasreflink(&mp->m_sb)) {
+		rrec = XFS_RMAP_REC_ADDR(block, 5);
+		rrec->rm_startblock = cpu_to_be32(xfs_refc_block(mp));
+		rrec->rm_blockcount = cpu_to_be32(1);
+		rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_REFC);
+		rrec->rm_offset = 0;
+		be16_add_cpu(&block->bb_numrecs, 1);
 	}
+}
+
+
+static void
+xfs_agfblock_init(
+	struct xfs_mount	*mp,
+	struct xfs_buf		*bp,
+	struct aghdr_init_data	*id)
+{
+	struct xfs_agf		*agf = XFS_BUF_TO_AGF(bp);
+	xfs_extlen_t		tmpsize;
 
-	agf = XFS_BUF_TO_AGF(bp);
 	agf->agf_magicnum = cpu_to_be32(XFS_AGF_MAGIC);
 	agf->agf_versionnum = cpu_to_be32(XFS_AGF_VERSION);
-	agf->agf_seqno = cpu_to_be32(agno);
-	agf->agf_length = cpu_to_be32(agsize);
+	agf->agf_seqno = cpu_to_be32(id->agno);
+	agf->agf_length = cpu_to_be32(id->agsize);
 	agf->agf_roots[XFS_BTNUM_BNOi] = cpu_to_be32(XFS_BNO_BLOCK(mp));
 	agf->agf_roots[XFS_BTNUM_CNTi] = cpu_to_be32(XFS_CNT_BLOCK(mp));
 	agf->agf_levels[XFS_BTNUM_BNOi] = cpu_to_be32(1);

@@ -125,7 +219,7 @@ xfs_grow_ag_headers(
 	agf->agf_flfirst = cpu_to_be32(1);
 	agf->agf_fllast = 0;
 	agf->agf_flcount = 0;
-	tmpsize = agsize - mp->m_ag_prealloc_blocks;
+	tmpsize = id->agsize - mp->m_ag_prealloc_blocks;
 	agf->agf_freeblks = cpu_to_be32(tmpsize);
 	agf->agf_longest = cpu_to_be32(tmpsize);
 	if (xfs_sb_version_hascrc(&mp->m_sb))

@@ -136,52 +230,42 @@ xfs_grow_ag_headers(
 		agf->agf_refcount_level = cpu_to_be32(1);
 		agf->agf_refcount_blocks = cpu_to_be32(1);
 	}
-	xfs_buf_delwri_queue(bp, buffer_list);
-	xfs_buf_relse(bp);
+}
 
-	/*
-	 * AG freelist header block
-	 */
-	bp = xfs_growfs_get_hdr_buf(mp,
-			XFS_AG_DADDR(mp, agno, XFS_AGFL_DADDR(mp)),
-			XFS_FSS_TO_BB(mp, 1), 0,
-			&xfs_agfl_buf_ops);
-	if (!bp) {
-		error = -ENOMEM;
-		goto out_error;
-	}
+static void
+xfs_agflblock_init(
+	struct xfs_mount	*mp,
+	struct xfs_buf		*bp,
+	struct aghdr_init_data	*id)
+{
+	struct xfs_agfl		*agfl = XFS_BUF_TO_AGFL(bp);
+	__be32			*agfl_bno;
+	int			bucket;
 
-	agfl = XFS_BUF_TO_AGFL(bp);
 	if (xfs_sb_version_hascrc(&mp->m_sb)) {
 		agfl->agfl_magicnum = cpu_to_be32(XFS_AGFL_MAGIC);
-		agfl->agfl_seqno = cpu_to_be32(agno);
+		agfl->agfl_seqno = cpu_to_be32(id->agno);
 		uuid_copy(&agfl->agfl_uuid, &mp->m_sb.sb_meta_uuid);
 	}
 
 	agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, bp);
 	for (bucket = 0; bucket < xfs_agfl_size(mp); bucket++)
 		agfl_bno[bucket] = cpu_to_be32(NULLAGBLOCK);
+}
 
-	xfs_buf_delwri_queue(bp, buffer_list);
-	xfs_buf_relse(bp);
-
-	/*
-	 * AG inode header block
-	 */
-	bp = xfs_growfs_get_hdr_buf(mp,
-			XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
-			XFS_FSS_TO_BB(mp, 1), 0,
-			&xfs_agi_buf_ops);
-	if (!bp) {
-		error = -ENOMEM;
-		goto out_error;
-	}
+static void
+xfs_agiblock_init(
+	struct xfs_mount	*mp,
+	struct xfs_buf		*bp,
+	struct aghdr_init_data	*id)
+{
+	struct xfs_agi		*agi = XFS_BUF_TO_AGI(bp);
+	int			bucket;
 
-	agi = XFS_BUF_TO_AGI(bp);
 	agi->agi_magicnum = cpu_to_be32(XFS_AGI_MAGIC);
 	agi->agi_versionnum = cpu_to_be32(XFS_AGI_VERSION);
-	agi->agi_seqno = cpu_to_be32(agno);
-	agi->agi_length = cpu_to_be32(agsize);
+	agi->agi_seqno = cpu_to_be32(id->agno);
+	agi->agi_length = cpu_to_be32(id->agsize);
 	agi->agi_count = 0;
 	agi->agi_root = cpu_to_be32(XFS_IBT_BLOCK(mp));
 	agi->agi_level = cpu_to_be32(1);

@@ -196,180 +280,133 @@ xfs_grow_ag_headers(
 	}
 	for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
 		agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
+}
 
-	xfs_buf_delwri_queue(bp, buffer_list);
-	xfs_buf_relse(bp);
-
-	/*
-	 * BNO btree root block
-	 */
-	bp = xfs_growfs_get_hdr_buf(mp,
-			XFS_AGB_TO_DADDR(mp, agno, XFS_BNO_BLOCK(mp)),
-			BTOBB(mp->m_sb.sb_blocksize), 0,
-			&xfs_allocbt_buf_ops);
+static int
+xfs_growfs_init_aghdr(
+	struct xfs_mount	*mp,
+	struct aghdr_init_data	*id,
+	void			(*work)(struct xfs_mount *, struct xfs_buf *,
+					struct aghdr_init_data *),
+	const struct xfs_buf_ops *ops)
 
-	if (!bp) {
-		error = -ENOMEM;
-		goto out_error;
-	}
+{
+	struct xfs_buf		*bp;
 
-	xfs_btree_init_block(mp, bp, XFS_BTNUM_BNO, 0, 1, agno, 0);
+	bp = xfs_growfs_get_hdr_buf(mp, id->daddr, id->numblks, 0, ops);
+	if (!bp)
+		return -ENOMEM;
 
-	arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
-	arec->ar_startblock = cpu_to_be32(mp->m_ag_prealloc_blocks);
-	arec->ar_blockcount = cpu_to_be32(
-		agsize - be32_to_cpu(arec->ar_startblock));
+	(*work)(mp, bp, id);
 
-	xfs_buf_delwri_queue(bp, buffer_list);
+	xfs_buf_delwri_queue(bp, &id->buffer_list);
 	xfs_buf_relse(bp);
+	return 0;
+}
 
-	/*
-	 * CNT btree root block
-	 */
-	bp = xfs_growfs_get_hdr_buf(mp,
-			XFS_AGB_TO_DADDR(mp, agno, XFS_CNT_BLOCK(mp)),
-			BTOBB(mp->m_sb.sb_blocksize), 0,
-			&xfs_allocbt_buf_ops);
-	if (!bp) {
-		error = -ENOMEM;
-		goto out_error;
-	}
-
-	xfs_btree_init_block(mp, bp, XFS_BTNUM_CNT, 0, 1, agno, 0);
+/*
+ * Write new AG headers to disk. Non-transactional, but written
+ * synchronously so they are completed prior to the growfs transaction
+ * being logged.
+ */
+static int
+xfs_grow_ag_headers(
+	struct xfs_mount	*mp,
+	struct aghdr_init_data	*id)
 
-	arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
-	arec->ar_startblock = cpu_to_be32(mp->m_ag_prealloc_blocks);
-	arec->ar_blockcount = cpu_to_be32(
-		agsize - be32_to_cpu(arec->ar_startblock));
-	*nfree += be32_to_cpu(arec->ar_blockcount);
+{
+	int			error = 0;
 
-	xfs_buf_delwri_queue(bp, buffer_list);
-	xfs_buf_relse(bp);
+	/* Account for AG free space in new AG */
+	id->nfree += id->agsize - mp->m_ag_prealloc_blocks;
 
-	/* RMAP btree root block */
-	if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
-		struct xfs_rmap_rec	*rrec;
-		struct xfs_btree_block	*block;
-
-		bp = xfs_growfs_get_hdr_buf(mp,
-			XFS_AGB_TO_DADDR(mp, agno, XFS_RMAP_BLOCK(mp)),
-			BTOBB(mp->m_sb.sb_blocksize), 0,
-			&xfs_rmapbt_buf_ops);
-		if (!bp) {
-			error = -ENOMEM;
-			goto out_error;
-		}
+	/* AG freespace header block */
+	id->daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGF_DADDR(mp));
+	id->numblks = XFS_FSS_TO_BB(mp, 1);
+	error = xfs_growfs_init_aghdr(mp, id, xfs_agfblock_init,
+					&xfs_agf_buf_ops);
+	if (error)
+		goto out_error;
 
-		xfs_btree_init_block(mp, bp, XFS_BTNUM_RMAP, 0, 0,
-					agno, 0);
-		block = XFS_BUF_TO_BLOCK(bp);
+	/* AG freelist header block */
+	id->daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGFL_DADDR(mp));
+	id->numblks = XFS_FSS_TO_BB(mp, 1);
+	error = xfs_growfs_init_aghdr(mp, id, xfs_agflblock_init,
+					&xfs_agfl_buf_ops);
+	if (error)
+		goto out_error;
 
+	/* AG inode header block */
+	id->daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGI_DADDR(mp));
+	id->numblks = XFS_FSS_TO_BB(mp, 1);
+	error = xfs_growfs_init_aghdr(mp, id, xfs_agiblock_init,
+					&xfs_agi_buf_ops);
+	if (error)
+		goto out_error;
 
-		/*
-		 * mark the AG header regions as static metadata The BNO
-		 * btree block is the first block after the headers, so
-		 * it's location defines the size of region the static
-		 * metadata consumes.
-		 *
-		 * Note: unlike mkfs, we never have to account for log
-		 * space when growing the data regions
-		 */
-		rrec = XFS_RMAP_REC_ADDR(block, 1);
-		rrec->rm_startblock = 0;
-		rrec->rm_blockcount = cpu_to_be32(XFS_BNO_BLOCK(mp));
-		rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_FS);
-		rrec->rm_offset = 0;
-		be16_add_cpu(&block->bb_numrecs, 1);
 
-		/* account freespace btree root blocks */
-		rrec = XFS_RMAP_REC_ADDR(block, 2);
-		rrec->rm_startblock = cpu_to_be32(XFS_BNO_BLOCK(mp));
-		rrec->rm_blockcount = cpu_to_be32(2);
-		rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
-		rrec->rm_offset = 0;
-		be16_add_cpu(&block->bb_numrecs, 1);
+	/* BNO btree root block */
+	id->daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_BNO_BLOCK(mp));
+	id->numblks = BTOBB(mp->m_sb.sb_blocksize);
+	error = xfs_growfs_init_aghdr(mp, id, xfs_bnoroot_init,
+				   &xfs_allocbt_buf_ops);
+	if (error)
+		goto out_error;
 
-		/* account inode btree root blocks */
-		rrec = XFS_RMAP_REC_ADDR(block, 3);
-		rrec->rm_startblock = cpu_to_be32(XFS_IBT_BLOCK(mp));
-		rrec->rm_blockcount = cpu_to_be32(XFS_RMAP_BLOCK(mp) -
-						XFS_IBT_BLOCK(mp));
-		rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_INOBT);
-		rrec->rm_offset = 0;
-		be16_add_cpu(&block->bb_numrecs, 1);
 
-		/* account for rmap btree root */
-		rrec = XFS_RMAP_REC_ADDR(block, 4);
-		rrec->rm_startblock = cpu_to_be32(XFS_RMAP_BLOCK(mp));
-		rrec->rm_blockcount = cpu_to_be32(1);
-		rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
-		rrec->rm_offset = 0;
-		be16_add_cpu(&block->bb_numrecs, 1);
+	/* CNT btree root block */
+	id->daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_CNT_BLOCK(mp));
+	id->numblks = BTOBB(mp->m_sb.sb_blocksize);
+	error = xfs_growfs_init_aghdr(mp, id, xfs_cntroot_init,
+				   &xfs_allocbt_buf_ops);
+	if (error)
+		goto out_error;
 
-		/* account for refc btree root */
-		if (xfs_sb_version_hasreflink(&mp->m_sb)) {
-			rrec = XFS_RMAP_REC_ADDR(block, 5);
-			rrec->rm_startblock = cpu_to_be32(xfs_refc_block(mp));
-			rrec->rm_blockcount = cpu_to_be32(1);
-			rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_REFC);
-			rrec->rm_offset = 0;
-			be16_add_cpu(&block->bb_numrecs, 1);
-		}
+	/* RMAP btree root block */
+	if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
+		id->daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_RMAP_BLOCK(mp));
+		id->numblks = BTOBB(mp->m_sb.sb_blocksize);
+		error = xfs_growfs_init_aghdr(mp, id, xfs_rmaproot_init,
+					   &xfs_rmapbt_buf_ops);
+		if (error)
+			goto out_error;
 
-		xfs_buf_delwri_queue(bp, buffer_list);
-		xfs_buf_relse(bp);
 	}
 
-	/*
-	 * INO btree root block
-	 */
-	bp = xfs_growfs_get_hdr_buf(mp,
-			XFS_AGB_TO_DADDR(mp, agno, XFS_IBT_BLOCK(mp)),
-			BTOBB(mp->m_sb.sb_blocksize), 0,
-			&xfs_inobt_buf_ops);
-	if (!bp) {
-		error = -ENOMEM;
+	/* INO btree root block */
+	id->daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_IBT_BLOCK(mp));
+	id->numblks = BTOBB(mp->m_sb.sb_blocksize);
+	id->type = XFS_BTNUM_INO;
+	error = xfs_growfs_init_aghdr(mp, id, xfs_btroot_init,
+				   &xfs_inobt_buf_ops);
+	if (error)
 		goto out_error;
-	}
 
-	xfs_btree_init_block(mp, bp, XFS_BTNUM_INO , 0, 0, agno, 0);
-	xfs_buf_delwri_queue(bp, buffer_list);
-	xfs_buf_relse(bp);
 
 	/*
 	 * FINO btree root block
 	 */
 	if (xfs_sb_version_hasfinobt(&mp->m_sb)) {
-		bp = xfs_growfs_get_hdr_buf(mp,
-			XFS_AGB_TO_DADDR(mp, agno, XFS_FIBT_BLOCK(mp)),
-			BTOBB(mp->m_sb.sb_blocksize), 0,
-			&xfs_inobt_buf_ops);
-		if (!bp) {
-			error = -ENOMEM;
+		id->daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_FIBT_BLOCK(mp));
+		id->numblks = BTOBB(mp->m_sb.sb_blocksize);
+		id->type = XFS_BTNUM_FINO;
+		error = xfs_growfs_init_aghdr(mp, id, xfs_btroot_init,
+					   &xfs_inobt_buf_ops);
+		if (error)
 			goto out_error;
-		}
-
-		xfs_btree_init_block(mp, bp, XFS_BTNUM_FINO, 0, 0, agno, 0);
-		xfs_buf_delwri_queue(bp, buffer_list);
-		xfs_buf_relse(bp);
 	}
 
 	/*
 	 * refcount btree root block
 	 */
 	if (xfs_sb_version_hasreflink(&mp->m_sb)) {
-		bp = xfs_growfs_get_hdr_buf(mp,
-			XFS_AGB_TO_DADDR(mp, agno, xfs_refc_block(mp)),
-			BTOBB(mp->m_sb.sb_blocksize), 0,
-			&xfs_refcountbt_buf_ops);
-		if (!bp) {
-			error = -ENOMEM;
+		id->daddr = XFS_AGB_TO_DADDR(mp, id->agno, xfs_refc_block(mp));
+		id->numblks = BTOBB(mp->m_sb.sb_blocksize);
+		id->type = XFS_BTNUM_REFC;
+		error = xfs_growfs_init_aghdr(mp, id, xfs_btroot_init,
+					   &xfs_refcountbt_buf_ops);
+		if (error)
 			goto out_error;
-		}
-
-		xfs_btree_init_block(mp, bp, XFS_BTNUM_REFC, 0, 0, agno, 0);
-		xfs_buf_delwri_queue(bp, buffer_list);
-		xfs_buf_relse(bp);
 	}
 
 out_error:

@@ -384,7 +421,6 @@ xfs_growfs_data_private(
 	xfs_agf_t		*agf;
 	xfs_agi_t		*agi;
 	xfs_agnumber_t		agno;
-	xfs_extlen_t		agsize;
 	xfs_buf_t		*bp;
 	int			dpct;
 	int			error, saved_error = 0;

@@ -392,11 +428,11 @@ xfs_growfs_data_private(
 	xfs_agnumber_t		nagimax = 0;
 	xfs_rfsblock_t		nb, nb_mod;
 	xfs_rfsblock_t		new;
-	xfs_rfsblock_t		nfree;
 	xfs_agnumber_t		oagcount;
 	int			pct;
 	xfs_trans_t		*tp;
 	LIST_HEAD		(buffer_list);
+	struct aghdr_init_data	id = {};
 
 	nb = in->newblocks;
 	pct = in->imaxpct;

@@ -448,27 +484,28 @@ xfs_growfs_data_private(
 	 * list to write, we can cancel the entire list without having written
 	 * anything.
 	 */
-	nfree = 0;
-	for (agno = nagcount - 1; agno >= oagcount; agno--, new -= agsize) {
-
-		if (agno == nagcount - 1)
-			agsize = nb -
-				(agno * (xfs_rfsblock_t)mp->m_sb.sb_agblocks);
+	INIT_LIST_HEAD(&id.buffer_list);
+	for (id.agno = nagcount - 1;
+	     id.agno >= oagcount;
+	     id.agno--, new -= id.agsize) {
+
+		if (id.agno == nagcount - 1)
+			id.agsize = nb -
+				(id.agno * (xfs_rfsblock_t)mp->m_sb.sb_agblocks);
 		else
-			agsize = mp->m_sb.sb_agblocks;
+			id.agsize = mp->m_sb.sb_agblocks;
 
-		error = xfs_grow_ag_headers(mp, agno, agsize, &nfree,
-					    &buffer_list);
+		error = xfs_grow_ag_headers(mp, &id);
 		if (error) {
-			xfs_buf_delwri_cancel(&buffer_list);
+			xfs_buf_delwri_cancel(&id.buffer_list);
 			goto error0;
 		}
 	}
-	error = xfs_buf_delwri_submit(&buffer_list);
+	error = xfs_buf_delwri_submit(&id.buffer_list);
 	if (error)
 		goto error0;
 
-	xfs_trans_agblocks_delta(tp, nfree);
+	xfs_trans_agblocks_delta(tp, id.nfree);
 
 	/*
 	 * There are new blocks in the old last a.g.

@@ -479,7 +516,7 @@ xfs_growfs_data_private(
 		/*
 		 * Change the agi length.
 		 */
-		error = xfs_ialloc_read_agi(mp, tp, agno, &bp);
+		error = xfs_ialloc_read_agi(mp, tp, id.agno, &bp);
 		if (error) {
 			goto error0;
 		}

@@ -492,7 +529,7 @@ xfs_growfs_data_private(
 		/*
 		 * Change agf length.
 		 */
-		error = xfs_alloc_read_agf(mp, tp, agno, 0, &bp);
+		error = xfs_alloc_read_agf(mp, tp, id.agno, 0, &bp);
 		if (error) {
 			goto error0;
 		}

@@ -511,13 +548,13 @@ xfs_growfs_data_private(
 		 * this doesn't actually exist in the rmap btree.
 		 */
 		xfs_rmap_ag_owner(&oinfo, XFS_RMAP_OWN_NULL);
-		error = xfs_rmap_free(tp, bp, agno,
+		error = xfs_rmap_free(tp, bp, id.agno,
 				be32_to_cpu(agf->agf_length) - new,
 				new, &oinfo);
 		if (error)
 			goto error0;
 		error = xfs_free_extent(tp,
-				XFS_AGB_TO_FSB(mp, agno,
+				XFS_AGB_TO_FSB(mp, id.agno,
 					be32_to_cpu(agf->agf_length) - new),
 				new, &oinfo, XFS_AG_RESV_NONE);
 		if (error)

@@ -534,8 +571,8 @@ xfs_growfs_data_private(
 	if (nb > mp->m_sb.sb_dblocks)
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_DBLOCKS,
 				 nb - mp->m_sb.sb_dblocks);
-	if (nfree)
-		xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, nfree);
+	if (id.nfree)
+		xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, id.nfree);
 	if (dpct)
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_IMAXPCT, dpct);
 	xfs_trans_set_sync(tp);

@@ -562,7 +599,7 @@ xfs_growfs_data_private(
 	if (new) {
 		struct xfs_perag	*pag;
 
-		pag = xfs_perag_get(mp, agno);
+		pag = xfs_perag_get(mp, id.agno);
 		error = xfs_ag_resv_free(pag);
 		xfs_perag_put(pag);
 		if (error)

index ec3c51ee8134..fb283d2cf42b 100644
@@ -282,12 +282,13 @@ xfs_agiblock_init(
 		agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
 }
 
+typedef void (*aghdr_init_work_f)(struct xfs_mount *mp, struct xfs_buf *bp,
+				  struct aghdr_init_data *id);
 static int
 xfs_growfs_init_aghdr(
 	struct xfs_mount	*mp,
 	struct aghdr_init_data	*id,
-	void			(*work)(struct xfs_mount *, struct xfs_buf *,
-					struct aghdr_init_data *),
+	aghdr_init_work_f	work,
 	const struct xfs_buf_ops *ops)
 
 {

@@ -304,6 +305,15 @@ xfs_growfs_init_aghdr(
 	return 0;
 }
 
+struct xfs_aghdr_grow_data {
+	xfs_daddr_t		daddr;
+	size_t			numblks;
+	const struct xfs_buf_ops *ops;
+	aghdr_init_work_f	work;
+	xfs_btnum_t		type;
+	bool			need_init;
+};
+
 /*
  * Write new AG headers to disk. Non-transactional, but written
  * synchronously so they are completed prior to the growfs transaction

@@ -315,101 +325,93 @@ xfs_grow_ag_headers(
 	struct aghdr_init_data	*id)
 
 {
+	struct xfs_aghdr_grow_data aghdr_data[] = {
+	{ /* AGF */
+		.daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGF_DADDR(mp)),
+		.numblks = XFS_FSS_TO_BB(mp, 1),
+		.ops = &xfs_agf_buf_ops,
+		.work = &xfs_agfblock_init,
+		.need_init = true
+	},
+	{ /* AGFL */
+		.daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGFL_DADDR(mp)),
+		.numblks = XFS_FSS_TO_BB(mp, 1),
+		.ops = &xfs_agfl_buf_ops,
+		.work = &xfs_agflblock_init,
+		.need_init = true
+	},
+	{ /* AGI */
+		.daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGI_DADDR(mp)),
+		.numblks = XFS_FSS_TO_BB(mp, 1),
+		.ops = &xfs_agi_buf_ops,
+		.work = &xfs_agiblock_init,
+		.need_init = true
+	},
+	{ /* BNO root block */
+		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_BNO_BLOCK(mp)),
+		.numblks = BTOBB(mp->m_sb.sb_blocksize),
+		.ops = &xfs_allocbt_buf_ops,
+		.work = &xfs_bnoroot_init,
+		.need_init = true
+	},
+	{ /* CNT root block */
+		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_CNT_BLOCK(mp)),
+		.numblks = BTOBB(mp->m_sb.sb_blocksize),
+		.ops = &xfs_allocbt_buf_ops,
+		.work = &xfs_cntroot_init,
+		.need_init = true
+	},
+	{ /* INO root block */
+		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_IBT_BLOCK(mp)),
+		.numblks = BTOBB(mp->m_sb.sb_blocksize),
+		.ops = &xfs_inobt_buf_ops,
+		.work = &xfs_btroot_init,
+		.type = XFS_BTNUM_INO,
+		.need_init = true
+	},
+	{ /* FINO root block */
+		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_FIBT_BLOCK(mp)),
+		.numblks = BTOBB(mp->m_sb.sb_blocksize),
+		.ops = &xfs_inobt_buf_ops,
+		.work = &xfs_btroot_init,
+		.type = XFS_BTNUM_FINO,
+		.need_init =  xfs_sb_version_hasfinobt(&mp->m_sb)
+	},
+	{ /* RMAP root block */
+		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_RMAP_BLOCK(mp)),
+		.numblks = BTOBB(mp->m_sb.sb_blocksize),
+		.ops = &xfs_rmapbt_buf_ops,
+		.work = &xfs_rmaproot_init,
+		.need_init = xfs_sb_version_hasrmapbt(&mp->m_sb)
+	},
+	{ /* REFC root block */
+		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, xfs_refc_block(mp)),
+		.numblks = BTOBB(mp->m_sb.sb_blocksize),
+		.ops = &xfs_refcountbt_buf_ops,
+		.work = &xfs_btroot_init,
+		.type = XFS_BTNUM_REFC,
+		.need_init = xfs_sb_version_hasreflink(&mp->m_sb)
+	},
+	{ /* NULL terminating block */
+		.daddr = XFS_BUF_DADDR_NULL,
+	}
+	};
+	struct  xfs_aghdr_grow_data *dp;
 	int			error = 0;
 
 	/* Account for AG free space in new AG */
 	id->nfree += id->agsize - mp->m_ag_prealloc_blocks;
+	for (dp = &aghdr_data[0]; dp->daddr != XFS_BUF_DADDR_NULL; dp++) {
+		if (!dp->need_init)
+			continue;
 
-	/* AG freespace header block */
-	id->daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGF_DADDR(mp));
-	id->numblks = XFS_FSS_TO_BB(mp, 1);
-	error = xfs_growfs_init_aghdr(mp, id, xfs_agfblock_init,
-					&xfs_agf_buf_ops);
-	if (error)
-		goto out_error;
-
-	/* AG freelist header block */
-	id->daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGFL_DADDR(mp));
-	id->numblks = XFS_FSS_TO_BB(mp, 1);
-	error = xfs_growfs_init_aghdr(mp, id, xfs_agflblock_init,
-					&xfs_agfl_buf_ops);
-	if (error)
-		goto out_error;
-
-	/* AG inode header block */
-	id->daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGI_DADDR(mp));
-	id->numblks = XFS_FSS_TO_BB(mp, 1);
-	error = xfs_growfs_init_aghdr(mp, id, xfs_agiblock_init,
-					&xfs_agi_buf_ops);
-	if (error)
-		goto out_error;
-
-
-	/* BNO btree root block */
-	id->daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_BNO_BLOCK(mp));
-	id->numblks = BTOBB(mp->m_sb.sb_blocksize);
-	error = xfs_growfs_init_aghdr(mp, id, xfs_bnoroot_init,
-				   &xfs_allocbt_buf_ops);
-	if (error)
-		goto out_error;
-
-
-	/* CNT btree root block */
-	id->daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_CNT_BLOCK(mp));
-	id->numblks = BTOBB(mp->m_sb.sb_blocksize);
-	error = xfs_growfs_init_aghdr(mp, id, xfs_cntroot_init,
-				   &xfs_allocbt_buf_ops);
-	if (error)
-		goto out_error;
-
-	/* RMAP btree root block */
-	if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
-		id->daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_RMAP_BLOCK(mp));
-		id->numblks = BTOBB(mp->m_sb.sb_blocksize);
-		error = xfs_growfs_init_aghdr(mp, id, xfs_rmaproot_init,
-					   &xfs_rmapbt_buf_ops);
-		if (error)
-			goto out_error;
-
-	}
-
-	/* INO btree root block */
-	id->daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_IBT_BLOCK(mp));
-	id->numblks = BTOBB(mp->m_sb.sb_blocksize);
-	id->type = XFS_BTNUM_INO;
-	error = xfs_growfs_init_aghdr(mp, id, xfs_btroot_init,
-				   &xfs_inobt_buf_ops);
-	if (error)
-		goto out_error;
-
-
-	/*
-	 * FINO btree root block
-	 */
-	if (xfs_sb_version_hasfinobt(&mp->m_sb)) {
-		id->daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_FIBT_BLOCK(mp));
-		id->numblks = BTOBB(mp->m_sb.sb_blocksize);
-		id->type = XFS_BTNUM_FINO;
-		error = xfs_growfs_init_aghdr(mp, id, xfs_btroot_init,
-					   &xfs_inobt_buf_ops);
-		if (error)
-			goto out_error;
-	}
-
-	/*
-	 * refcount btree root block
-	 */
-	if (xfs_sb_version_hasreflink(&mp->m_sb)) {
-		id->daddr = XFS_AGB_TO_DADDR(mp, id->agno, xfs_refc_block(mp));
-		id->numblks = BTOBB(mp->m_sb.sb_blocksize);
-		id->type = XFS_BTNUM_REFC;
-		error = xfs_growfs_init_aghdr(mp, id, xfs_btroot_init,
-					   &xfs_refcountbt_buf_ops);
+		id->daddr = dp->daddr;
+		id->numblks = dp->numblks;
+		id->type = dp->type;
+		error = xfs_growfs_init_aghdr(mp, id, dp->work, dp->ops);
 		if (error)
-			goto out_error;
+			break;
 	}
-
-out_error:
 	return error;
 }
 

index fb283d2cf42b..4e66d390e2a4 100644
@@ -424,25 +424,21 @@ xfs_growfs_data_private(
 	xfs_agi_t		*agi;
 	xfs_agnumber_t		agno;
 	xfs_buf_t		*bp;
-	int			dpct;
 	int			error, saved_error = 0;
 	xfs_agnumber_t		nagcount;
 	xfs_agnumber_t		nagimax = 0;
 	xfs_rfsblock_t		nb, nb_mod;
 	xfs_rfsblock_t		new;
 	xfs_agnumber_t		oagcount;
-	int			pct;
 	xfs_trans_t		*tp;
 	LIST_HEAD		(buffer_list);
 	struct aghdr_init_data	id = {};
 
 	nb = in->newblocks;
-	pct = in->imaxpct;
-	if (nb < mp->m_sb.sb_dblocks || pct < 0 || pct > 100)
+	if (nb < mp->m_sb.sb_dblocks)
 		return -EINVAL;
 	if ((error = xfs_sb_validate_fsb_count(&mp->m_sb, nb)))
 		return error;
-	dpct = pct - mp->m_sb.sb_imax_pct;
 	error = xfs_buf_read_uncached(mp->m_ddev_targp,
 				XFS_FSB_TO_BB(mp, nb) - XFS_FSS_TO_BB(mp, 1),
 				XFS_FSS_TO_BB(mp, 1), 0, &bp, NULL);

@@ -575,8 +571,6 @@ xfs_growfs_data_private(
 				 nb - mp->m_sb.sb_dblocks);
 	if (id.nfree)
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, id.nfree);
-	if (dpct)
-		xfs_trans_mod_sb(tp, XFS_TRANS_SB_IMAXPCT, dpct);
 	xfs_trans_set_sync(tp);
 	error = xfs_trans_commit(tp);
 	if (error)

@@ -585,12 +579,6 @@ xfs_growfs_data_private(
 	/* New allocation groups fully initialized, so update mount struct */
 	if (nagimax)
 		mp->m_maxagi = nagimax;
-	if (mp->m_sb.sb_imax_pct) {
-		uint64_t icount = mp->m_sb.sb_dblocks * mp->m_sb.sb_imax_pct;
-		do_div(icount, 100);
-		mp->m_maxicount = icount << mp->m_sb.sb_inopblog;
-	} else
-		mp->m_maxicount = 0;
 	xfs_set_low_space_thresholds(mp);
 	mp->m_alloc_set_aside = xfs_alloc_set_aside(mp);
 

@@ -694,25 +682,68 @@ xfs_growfs_log_private(
 	return -ENOSYS;
 }
 
+static int
+xfs_growfs_imaxpct(
+	struct xfs_mount	*mp,
+	__u32			imaxpct)
+{
+	struct xfs_trans	*tp;
+	int64_t			dpct;
+	int			error;
+
+	if (imaxpct > 100)
+		return -EINVAL;
+
+	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growdata,
+			XFS_GROWFS_SPACE_RES(mp), 0, XFS_TRANS_RESERVE, &tp);
+	if (error)
+		return error;
+
+	dpct = (int64_t)imaxpct - mp->m_sb.sb_imax_pct;
+	xfs_trans_mod_sb(tp, XFS_TRANS_SB_IMAXPCT, dpct);
+	xfs_trans_set_sync(tp);
+	return xfs_trans_commit(tp);
+}
+
 /*
  * protected versions of growfs function acquire and release locks on the mount
  * point - exported through ioctls: XFS_IOC_FSGROWFSDATA, XFS_IOC_FSGROWFSLOG,
  * XFS_IOC_FSGROWFSRT
  */
-
-
 int
 xfs_growfs_data(
-	xfs_mount_t		*mp,
-	xfs_growfs_data_t	*in)
+	struct xfs_mount	*mp,
+	struct xfs_growfs_data	*in)
 {
-	int error;
+	int			error = 0;
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 	if (!mutex_trylock(&mp->m_growlock))
 		return -EWOULDBLOCK;
-	error = xfs_growfs_data_private(mp, in);
+
+	/* update imaxpct separately to the physical grow of the filesystem */
+	if (in->imaxpct != mp->m_sb.sb_imax_pct) {
+		error = xfs_growfs_imaxpct(mp, in->imaxpct);
+		if (error)
+			goto out_error;
+	}
+
+	if (in->newblocks != mp->m_sb.sb_dblocks) {
+		error = xfs_growfs_data_private(mp, in);
+		if (error)
+			goto out_error;
+	}
+
+	/* Post growfs calculations needed to reflect new state in operations */
+	if (mp->m_sb.sb_imax_pct) {
+		uint64_t icount = mp->m_sb.sb_dblocks * mp->m_sb.sb_imax_pct;
+		do_div(icount, 100);
+		mp->m_maxicount = icount << mp->m_sb.sb_inopblog;
+	} else
+		mp->m_maxicount = 0;
+
+out_error:
 	/*
 	 * Increment the generation unconditionally, the error could be from
 	 * updating the secondary superblocks, in which case the new size

index 4e66d390e2a4..a718bb002cf4 100644
@@ -422,9 +422,8 @@ xfs_growfs_data_private(
 {
 	xfs_agf_t		*agf;
 	xfs_agi_t		*agi;
-	xfs_agnumber_t		agno;
 	xfs_buf_t		*bp;
-	int			error, saved_error = 0;
+	int			error;
 	xfs_agnumber_t		nagcount;
 	xfs_agnumber_t		nagimax = 0;
 	xfs_rfsblock_t		nb, nb_mod;

@@ -496,12 +495,12 @@ xfs_growfs_data_private(
 		error = xfs_grow_ag_headers(mp, &id);
 		if (error) {
 			xfs_buf_delwri_cancel(&id.buffer_list);
-			goto error0;
+			goto out_trans_cancel;
 		}
 	}
 	error = xfs_buf_delwri_submit(&id.buffer_list);
 	if (error)
-		goto error0;
+		goto out_trans_cancel;
 
 	xfs_trans_agblocks_delta(tp, id.nfree);
 

@@ -515,22 +514,23 @@ xfs_growfs_data_private(
 		 * Change the agi length.
 		 */
 		error = xfs_ialloc_read_agi(mp, tp, id.agno, &bp);
-		if (error) {
-			goto error0;
-		}
+		if (error)
+			goto out_trans_cancel;
+
 		ASSERT(bp);
 		agi = XFS_BUF_TO_AGI(bp);
 		be32_add_cpu(&agi->agi_length, new);
 		ASSERT(nagcount == oagcount ||
 		       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);
-		if (error) {
-			goto error0;
-		}
+		if (error)
+			goto out_trans_cancel;
+
 		ASSERT(bp);
 		agf = XFS_BUF_TO_AGF(bp);
 		be32_add_cpu(&agf->agf_length, new);

@@ -550,13 +550,13 @@ xfs_growfs_data_private(
 				be32_to_cpu(agf->agf_length) - new,
 				new, &oinfo);
 		if (error)
-			goto error0;
+			goto out_trans_cancel;
 		error = xfs_free_extent(tp,
 				XFS_AGB_TO_FSB(mp, id.agno,
 					be32_to_cpu(agf->agf_length) - new),
 				new, &oinfo, XFS_AG_RESV_NONE);
 		if (error)
-			goto error0;
+			goto out_trans_cancel;
 	}
 
 	/*

@@ -593,16 +593,86 @@ xfs_growfs_data_private(
 		error = xfs_ag_resv_free(pag);
 		xfs_perag_put(pag);
 		if (error)
-			goto out;
+			return error;
 	}
 
-	/* Reserve AG metadata blocks. */
+	/*
+	 * Reserve AG metadata blocks. ENOSPC here does not mean there was a
+	 * growfs failure, just that there still isn't space for new user data
+	 * after the grow has been run.
+	 */
 	error = xfs_fs_reserve_ag_blocks(mp);
-	if (error && error != -ENOSPC)
-		goto out;
+	if (error == -ENOSPC)
+		error = 0;
+	return error;
+
+out_trans_cancel:
+	xfs_trans_cancel(tp);
+	return error;
+}
+
+static int
+xfs_growfs_log_private(
+	xfs_mount_t		*mp,	/* mount point for filesystem */
+	xfs_growfs_log_t	*in)	/* growfs log input struct */
+{
+	xfs_extlen_t		nb;
+
+	nb = in->newblocks;
+	if (nb < XFS_MIN_LOG_BLOCKS || nb < XFS_B_TO_FSB(mp, XFS_MIN_LOG_BYTES))
+		return -EINVAL;
+	if (nb == mp->m_sb.sb_logblocks &&
+	    in->isint == (mp->m_sb.sb_logstart != 0))
+		return -EINVAL;
+	/*
+	 * Moving the log is hard, need new interfaces to sync
+	 * the log first, hold off all activity while moving it.
+	 * Can have shorter or longer log in the same space,
+	 * or transform internal to external log or vice versa.
+	 */
+	return -ENOSYS;
+}
+
+static int
+xfs_growfs_imaxpct(
+	struct xfs_mount	*mp,
+	__u32			imaxpct)
+{
+	struct xfs_trans	*tp;
+	int			dpct;
+	int			error;
+
+	if (imaxpct > 100)
+		return -EINVAL;
+
+	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growdata,
+			XFS_GROWFS_SPACE_RES(mp), 0, XFS_TRANS_RESERVE, &tp);
+	if (error)
+		return error;
+
+	dpct = imaxpct - mp->m_sb.sb_imax_pct;
+	xfs_trans_mod_sb(tp, XFS_TRANS_SB_IMAXPCT, dpct);
+	xfs_trans_set_sync(tp);
+	return xfs_trans_commit(tp);
+}
+
+/*
+ * After a grow operation, we need to update all the secondary superblocks
+ * to match the new state of the primary. Read/init the superblocks and update
+ * them appropriately.
+ */
+static int
+xfs_growfs_update_superblocks(
+	struct xfs_mount	*mp,
+	xfs_agnumber_t		oagcount)
+{
+	struct xfs_buf		*bp;
+	xfs_agnumber_t		agno;
+	int			saved_error = 0;
+	int			error = 0;
 
 	/* update secondary superblocks. */
-	for (agno = 1; agno < nagcount; agno++) {
+	for (agno = 1; agno < mp->m_sb.sb_agcount; agno++) {
 		error = 0;
 		/*
 		 * new secondary superblocks need to be zeroed, not read from

@@ -652,57 +722,7 @@ xfs_growfs_data_private(
 		}
 	}
 
- out:
 	return saved_error ? saved_error : error;
-
- error0:
-	xfs_trans_cancel(tp);
-	return error;
-}
-
-static int
-xfs_growfs_log_private(
-	xfs_mount_t		*mp,	/* mount point for filesystem */
-	xfs_growfs_log_t	*in)	/* growfs log input struct */
-{
-	xfs_extlen_t		nb;
-
-	nb = in->newblocks;
-	if (nb < XFS_MIN_LOG_BLOCKS || nb < XFS_B_TO_FSB(mp, XFS_MIN_LOG_BYTES))
-		return -EINVAL;
-	if (nb == mp->m_sb.sb_logblocks &&
-	    in->isint == (mp->m_sb.sb_logstart != 0))
-		return -EINVAL;
-	/*
-	 * Moving the log is hard, need new interfaces to sync
-	 * the log first, hold off all activity while moving it.
-	 * Can have shorter or longer log in the same space,
-	 * or transform internal to external log or vice versa.
-	 */
-	return -ENOSYS;
-}
-
-static int
-xfs_growfs_imaxpct(
-	struct xfs_mount	*mp,
-	__u32			imaxpct)
-{
-	struct xfs_trans	*tp;
-	int64_t			dpct;
-	int			error;
-
-	if (imaxpct > 100)
-		return -EINVAL;
-
-	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growdata,
-			XFS_GROWFS_SPACE_RES(mp), 0, XFS_TRANS_RESERVE, &tp);
-	if (error)
-		return error;
-
-	dpct = (int64_t)imaxpct - mp->m_sb.sb_imax_pct;
-	xfs_trans_mod_sb(tp, XFS_TRANS_SB_IMAXPCT, dpct);
-	xfs_trans_set_sync(tp);
-	return xfs_trans_commit(tp);
 }
 
 /*

@@ -715,6 +735,7 @@ xfs_growfs_data(
 	struct xfs_mount	*mp,
 	struct xfs_growfs_data	*in)
 {
+	xfs_agnumber_t		oagcount;
 	int			error = 0;
 
 	if (!capable(CAP_SYS_ADMIN))

@@ -729,6 +750,7 @@ xfs_growfs_data(
 			goto out_error;
 	}
 
+	oagcount = mp->m_sb.sb_agcount;
 	if (in->newblocks != mp->m_sb.sb_dblocks) {
 		error = xfs_growfs_data_private(mp, in);
 		if (error)

@@ -743,6 +765,9 @@ xfs_growfs_data(
 	} else
 		mp->m_maxicount = 0;
 
+	/* Update secondary superblocks now the physical grow has completed */
+	error = xfs_growfs_update_superblocks(mp, oagcount);
+
 out_error:
 	/*
 	 * Increment the generation unconditionally, the error could be from