1 files changed, 1042 insertions, 0 deletions

diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c
new file mode 100644
index 000000000..bb0c700af
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_ag.c
@@ -0,0 +1,1042 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2000-2005 Silicon Graphics, Inc.
+ * Copyright (c) 2018 Red Hat, Inc.
+ * All rights reserved.
+ */
+
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_bit.h"
+#include "xfs_sb.h"
+#include "xfs_mount.h"
+#include "xfs_btree.h"
+#include "xfs_alloc_btree.h"
+#include "xfs_rmap_btree.h"
+#include "xfs_alloc.h"
+#include "xfs_ialloc.h"
+#include "xfs_rmap.h"
+#include "xfs_ag.h"
+#include "xfs_ag_resv.h"
+#include "xfs_health.h"
+#include "xfs_error.h"
+#include "xfs_bmap.h"
+#include "xfs_defer.h"
+#include "xfs_log_format.h"
+#include "xfs_trans.h"
+#include "xfs_trace.h"
+#include "xfs_inode.h"
+#include "xfs_icache.h"
+
+
+/*
+ * Passive reference counting access wrappers to the perag structures.  If the
+ * per-ag structure is to be freed, the freeing code is responsible for cleaning
+ * up objects with passive references before freeing the structure. This is
+ * things like cached buffers.
+ */
+struct xfs_perag *
+xfs_perag_get(
+	struct xfs_mount	*mp,
+	xfs_agnumber_t		agno)
+{
+	struct xfs_perag	*pag;
+	int			ref = 0;
+
+	rcu_read_lock();
+	pag = radix_tree_lookup(&mp->m_perag_tree, agno);
+	if (pag) {
+		ASSERT(atomic_read(&pag->pag_ref) >= 0);
+		ref = atomic_inc_return(&pag->pag_ref);
+	}
+	rcu_read_unlock();
+	trace_xfs_perag_get(mp, agno, ref, _RET_IP_);
+	return pag;
+}
+
+/*
+ * search from @first to find the next perag with the given tag set.
+ */
+struct xfs_perag *
+xfs_perag_get_tag(
+	struct xfs_mount	*mp,
+	xfs_agnumber_t		first,
+	unsigned int		tag)
+{
+	struct xfs_perag	*pag;
+	int			found;
+	int			ref;
+
+	rcu_read_lock();
+	found = radix_tree_gang_lookup_tag(&mp->m_perag_tree,
+					(void **)&pag, first, 1, tag);
+	if (found <= 0) {
+		rcu_read_unlock();
+		return NULL;
+	}
+	ref = atomic_inc_return(&pag->pag_ref);
+	rcu_read_unlock();
+	trace_xfs_perag_get_tag(mp, pag->pag_agno, ref, _RET_IP_);
+	return pag;
+}
+
+void
+xfs_perag_put(
+	struct xfs_perag	*pag)
+{
+	int	ref;
+
+	ASSERT(atomic_read(&pag->pag_ref) > 0);
+	ref = atomic_dec_return(&pag->pag_ref);
+	trace_xfs_perag_put(pag->pag_mount, pag->pag_agno, ref, _RET_IP_);
+}
+
+/*
+ * xfs_initialize_perag_data
+ *
+ * Read in each per-ag structure so we can count up the number of
+ * allocated inodes, free inodes and used filesystem blocks as this
+ * information is no longer persistent in the superblock. Once we have
+ * this information, write it into the in-core superblock structure.
+ */
+int
+xfs_initialize_perag_data(
+	struct xfs_mount	*mp,
+	xfs_agnumber_t		agcount)
+{
+	xfs_agnumber_t		index;
+	struct xfs_perag	*pag;
+	struct xfs_sb		*sbp = &mp->m_sb;
+	uint64_t		ifree = 0;
+	uint64_t		ialloc = 0;
+	uint64_t		bfree = 0;
+	uint64_t		bfreelst = 0;
+	uint64_t		btree = 0;
+	uint64_t		fdblocks;
+	int			error = 0;
+
+	for (index = 0; index < agcount; index++) {
+		/*
+		 * Read the AGF and AGI buffers to populate the per-ag
+		 * structures for us.
+		 */
+		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;
+		}
+
+		ifree += pag->pagi_freecount;
+		ialloc += pag->pagi_count;
+		bfree += pag->pagf_freeblks;
+		bfreelst += pag->pagf_flcount;
+		btree += pag->pagf_btreeblks;
+		xfs_perag_put(pag);
+	}
+	fdblocks = bfree + bfreelst + btree;
+
+	/*
+	 * If the new summary counts are obviously incorrect, fail the
+	 * mount operation because that implies the AGFs are also corrupt.
+	 * Clear FS_COUNTERS so that we don't unmount with a dirty log, which
+	 * will prevent xfs_repair from fixing anything.
+	 */
+	if (fdblocks > sbp->sb_dblocks || ifree > ialloc) {
+		xfs_alert(mp, "AGF corruption. Please run xfs_repair.");
+		error = -EFSCORRUPTED;
+		goto out;
+	}
+
+	/* Overwrite incore superblock counters with just-read data */
+	spin_lock(&mp->m_sb_lock);
+	sbp->sb_ifree = ifree;
+	sbp->sb_icount = ialloc;
+	sbp->sb_fdblocks = fdblocks;
+	spin_unlock(&mp->m_sb_lock);
+
+	xfs_reinit_percpu_counters(mp);
+out:
+	xfs_fs_mark_healthy(mp, XFS_SICK_FS_COUNTERS);
+	return error;
+}
+
+STATIC void
+__xfs_free_perag(
+	struct rcu_head	*head)
+{
+	struct xfs_perag *pag = container_of(head, struct xfs_perag, rcu_head);
+
+	ASSERT(!delayed_work_pending(&pag->pag_blockgc_work));
+	kmem_free(pag);
+}
+
+/*
+ * Free up the per-ag resources associated with the mount structure.
+ */
+void
+xfs_free_perag(
+	struct xfs_mount	*mp)
+{
+	struct xfs_perag	*pag;
+	xfs_agnumber_t		agno;
+
+	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
+		spin_lock(&mp->m_perag_lock);
+		pag = radix_tree_delete(&mp->m_perag_tree, agno);
+		spin_unlock(&mp->m_perag_lock);
+		ASSERT(pag);
+		XFS_IS_CORRUPT(pag->pag_mount, atomic_read(&pag->pag_ref) != 0);
+
+		cancel_delayed_work_sync(&pag->pag_blockgc_work);
+		xfs_buf_hash_destroy(pag);
+
+		call_rcu(&pag->rcu_head, __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;
+	xfs_agnumber_t		index;
+	xfs_agnumber_t		first_initialised = NULLAGNUMBER;
+	int			error;
+
+	/*
+	 * Walk the current per-ag tree so we don't try to initialise AGs
+	 * that already exist (growfs case). Allocate and insert all the
+	 * AGs we don't find ready for initialisation.
+	 */
+	for (index = 0; index < agcount; index++) {
+		pag = xfs_perag_get(mp, index);
+		if (pag) {
+			xfs_perag_put(pag);
+			continue;
+		}
+
+		pag = kmem_zalloc(sizeof(*pag), KM_MAYFAIL);
+		if (!pag) {
+			error = -ENOMEM;
+			goto out_unwind_new_pags;
+		}
+		pag->pag_agno = index;
+		pag->pag_mount = mp;
+
+		error = radix_tree_preload(GFP_NOFS);
+		if (error)
+			goto out_free_pag;
+
+		spin_lock(&mp->m_perag_lock);
+		if (radix_tree_insert(&mp->m_perag_tree, index, pag)) {
+			WARN_ON_ONCE(1);
+			spin_unlock(&mp->m_perag_lock);
+			radix_tree_preload_end();
+			error = -EEXIST;
+			goto out_free_pag;
+		}
+		spin_unlock(&mp->m_perag_lock);
+		radix_tree_preload_end();
+
+#ifdef __KERNEL__
+		/* Place kernel structure only init below this point. */
+		spin_lock_init(&pag->pag_ici_lock);
+		spin_lock_init(&pag->pagb_lock);
+		spin_lock_init(&pag->pag_state_lock);
+		INIT_DELAYED_WORK(&pag->pag_blockgc_work, xfs_blockgc_worker);
+		INIT_RADIX_TREE(&pag->pag_ici_root, GFP_ATOMIC);
+		init_waitqueue_head(&pag->pagb_wait);
+		pag->pagb_count = 0;
+		pag->pagb_tree = RB_ROOT;
+#endif /* __KERNEL__ */
+
+		error = xfs_buf_hash_init(pag);
+		if (error)
+			goto out_remove_pag;
+
+		/* 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);
+
+	if (maxagi)
+		*maxagi = index;
+
+	mp->m_ag_prealloc_blocks = xfs_prealloc_blocks(mp);
+	return 0;
+
+out_remove_pag:
+	radix_tree_delete(&mp->m_perag_tree, index);
+out_free_pag:
+	kmem_free(pag);
+out_unwind_new_pags:
+	/* unwind any prior newly initialized pags */
+	for (index = first_initialised; index < agcount; index++) {
+		pag = radix_tree_delete(&mp->m_perag_tree, index);
+		if (!pag)
+			break;
+		xfs_buf_hash_destroy(pag);
+		kmem_free(pag);
+	}
+	return error;
+}
+
+static int
+xfs_get_aghdr_buf(
+	struct xfs_mount	*mp,
+	xfs_daddr_t		blkno,
+	size_t			numblks,
+	struct xfs_buf		**bpp,
+	const struct xfs_buf_ops *ops)
+{
+	struct xfs_buf		*bp;
+	int			error;
+
+	error = xfs_buf_get_uncached(mp->m_ddev_targp, numblks, 0, &bp);
+	if (error)
+		return error;
+
+	bp->b_maps[0].bm_bn = blkno;
+	bp->b_ops = ops;
+
+	*bpp = bp;
+	return 0;
+}
+
+/*
+ * Generic btree root block init function
+ */
+static void
+xfs_btroot_init(
+	struct xfs_mount	*mp,
+	struct xfs_buf		*bp,
+	struct aghdr_init_data	*id)
+{
+	xfs_btree_init_block(mp, bp, id->type, 0, 0, id->agno);
+}
+
+/* Finish initializing a free space btree. */
+static void
+xfs_freesp_init_recs(
+	struct xfs_mount	*mp,
+	struct xfs_buf		*bp,
+	struct aghdr_init_data	*id)
+{
+	struct xfs_alloc_rec	*arec;
+	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
+
+	arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
+	arec->ar_startblock = cpu_to_be32(mp->m_ag_prealloc_blocks);
+
+	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);
+
+		ASSERT(start >= mp->m_ag_prealloc_blocks);
+		if (start != mp->m_ag_prealloc_blocks) {
+			/*
+			 * Modify first record to pad stripe align of log
+			 */
+			arec->ar_blockcount = cpu_to_be32(start -
+						mp->m_ag_prealloc_blocks);
+			nrec = arec + 1;
+
+			/*
+			 * Insert second record at start of internal log
+			 * which then gets trimmed.
+			 */
+			nrec->ar_startblock = cpu_to_be32(
+					be32_to_cpu(arec->ar_startblock) +
+					be32_to_cpu(arec->ar_blockcount));
+			arec = nrec;
+			be16_add_cpu(&block->bb_numrecs, 1);
+		}
+		/*
+		 * Change record start to after the internal log
+		 */
+		be32_add_cpu(&arec->ar_startblock, mp->m_sb.sb_logblocks);
+	}
+
+	/*
+	 * Calculate the record block count and check for the case where
+	 * the log might have consumed all available space in the AG. If
+	 * so, reset the record count to 0 to avoid exposure of an invalid
+	 * record start block.
+	 */
+	arec->ar_blockcount = cpu_to_be32(id->agsize -
+					  be32_to_cpu(arec->ar_startblock));
+	if (!arec->ar_blockcount)
+		block->bb_numrecs = 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)
+{
+	xfs_btree_init_block(mp, bp, XFS_BTNUM_BNO, 0, 1, id->agno);
+	xfs_freesp_init_recs(mp, bp, id);
+}
+
+static void
+xfs_cntroot_init(
+	struct xfs_mount	*mp,
+	struct xfs_buf		*bp,
+	struct aghdr_init_data	*id)
+{
+	xfs_btree_init_block(mp, bp, XFS_BTNUM_CNT, 0, 1, id->agno);
+	xfs_freesp_init_recs(mp, bp, id);
+}
+
+/*
+ * 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);
+
+	/*
+	 * 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;
+
+	/* 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_has_reflink(mp)) {
+		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);
+	}
+
+	/* account for the log space */
+	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(
+				XFS_FSB_TO_AGBNO(mp, mp->m_sb.sb_logstart));
+		rrec->rm_blockcount = cpu_to_be32(mp->m_sb.sb_logblocks);
+		rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_LOG);
+		rrec->rm_offset = 0;
+		be16_add_cpu(&block->bb_numrecs, 1);
+	}
+}
+
+/*
+ * Initialise new secondary superblocks with the pre-grow geometry, but mark
+ * them as "in progress" so we know they haven't yet been activated. This will
+ * get cleared when the update with the new geometry information is done after
+ * changes to the primary are committed. This isn't strictly necessary, but we
+ * get it for free with the delayed buffer write lists and it means we can tell
+ * if a grow operation didn't complete properly after the fact.
+ */
+static void
+xfs_sbblock_init(
+	struct xfs_mount	*mp,
+	struct xfs_buf		*bp,
+	struct aghdr_init_data	*id)
+{
+	struct xfs_dsb		*dsb = bp->b_addr;
+
+	xfs_sb_to_disk(dsb, &mp->m_sb);
+	dsb->sb_inprogress = 1;
+}
+
+static void
+xfs_agfblock_init(
+	struct xfs_mount	*mp,
+	struct xfs_buf		*bp,
+	struct aghdr_init_data	*id)
+{
+	struct xfs_agf		*agf = bp->b_addr;
+	xfs_extlen_t		tmpsize;
+
+	agf->agf_magicnum = cpu_to_be32(XFS_AGF_MAGIC);
+	agf->agf_versionnum = cpu_to_be32(XFS_AGF_VERSION);
+	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);
+	agf->agf_levels[XFS_BTNUM_CNTi] = cpu_to_be32(1);
+	if (xfs_has_rmapbt(mp)) {
+		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 = id->agsize - mp->m_ag_prealloc_blocks;
+	agf->agf_freeblks = cpu_to_be32(tmpsize);
+	agf->agf_longest = cpu_to_be32(tmpsize);
+	if (xfs_has_crc(mp))
+		uuid_copy(&agf->agf_uuid, &mp->m_sb.sb_meta_uuid);
+	if (xfs_has_reflink(mp)) {
+		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);
+	}
+
+	if (xfs_ag_contains_log(mp, id->agno)) {
+		int64_t	logblocks = mp->m_sb.sb_logblocks;
+
+		be32_add_cpu(&agf->agf_freeblks, -logblocks);
+		agf->agf_longest = cpu_to_be32(id->agsize -
+			XFS_FSB_TO_AGBNO(mp, mp->m_sb.sb_logstart) - logblocks);
+	}
+}
+
+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;
+
+	if (xfs_has_crc(mp)) {
+		agfl->agfl_magicnum = cpu_to_be32(XFS_AGFL_MAGIC);
+		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(bp);
+	for (bucket = 0; bucket < xfs_agfl_size(mp); bucket++)
+		agfl_bno[bucket] = cpu_to_be32(NULLAGBLOCK);
+}
+
+static void
+xfs_agiblock_init(
+	struct xfs_mount	*mp,
+	struct xfs_buf		*bp,
+	struct aghdr_init_data	*id)
+{
+	struct xfs_agi		*agi = bp->b_addr;
+	int			bucket;
+
+	agi->agi_magicnum = cpu_to_be32(XFS_AGI_MAGIC);
+	agi->agi_versionnum = cpu_to_be32(XFS_AGI_VERSION);
+	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);
+	agi->agi_freecount = 0;
+	agi->agi_newino = cpu_to_be32(NULLAGINO);
+	agi->agi_dirino = cpu_to_be32(NULLAGINO);
+	if (xfs_has_crc(mp))
+		uuid_copy(&agi->agi_uuid, &mp->m_sb.sb_meta_uuid);
+	if (xfs_has_finobt(mp)) {
+		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);
+	if (xfs_has_inobtcounts(mp)) {
+		agi->agi_iblocks = cpu_to_be32(1);
+		if (xfs_has_finobt(mp))
+			agi->agi_fblocks = cpu_to_be32(1);
+	}
+}
+
+typedef void (*aghdr_init_work_f)(struct xfs_mount *mp, struct xfs_buf *bp,
+				  struct aghdr_init_data *id);
+static int
+xfs_ag_init_hdr(
+	struct xfs_mount	*mp,
+	struct aghdr_init_data	*id,
+	aghdr_init_work_f	work,
+	const struct xfs_buf_ops *ops)
+{
+	struct xfs_buf		*bp;
+	int			error;
+
+	error = xfs_get_aghdr_buf(mp, id->daddr, id->numblks, &bp, ops);
+	if (error)
+		return error;
+
+	(*work)(mp, bp, id);
+
+	xfs_buf_delwri_queue(bp, &id->buffer_list);
+	xfs_buf_relse(bp);
+	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;
+};
+
+/*
+ * Prepare new AG headers to be written to disk. We use uncached buffers here,
+ * as it is assumed these new AG headers are currently beyond the currently
+ * valid filesystem address space. Using cached buffers would trip over EOFS
+ * corruption detection alogrithms in the buffer cache lookup routines.
+ *
+ * This is a non-transactional function, but the prepared buffers are added to a
+ * delayed write buffer list supplied by the caller so they can submit them to
+ * disk and wait on them as required.
+ */
+int
+xfs_ag_init_headers(
+	struct xfs_mount	*mp,
+	struct aghdr_init_data	*id)
+
+{
+	struct xfs_aghdr_grow_data aghdr_data[] = {
+	{ /* SB */
+		.daddr = XFS_AG_DADDR(mp, id->agno, XFS_SB_DADDR),
+		.numblks = XFS_FSS_TO_BB(mp, 1),
+		.ops = &xfs_sb_buf_ops,
+		.work = &xfs_sbblock_init,
+		.need_init = true
+	},
+	{ /* 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_bnobt_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_cntbt_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_finobt_buf_ops,
+		.work = &xfs_btroot_init,
+		.type = XFS_BTNUM_FINO,
+		.need_init =  xfs_has_finobt(mp)
+	},
+	{ /* 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_has_rmapbt(mp)
+	},
+	{ /* 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_has_reflink(mp)
+	},
+	{ /* 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;
+
+		id->daddr = dp->daddr;
+		id->numblks = dp->numblks;
+		id->type = dp->type;
+		error = xfs_ag_init_hdr(mp, id, dp->work, dp->ops);
+		if (error)
+			break;
+	}
+	return error;
+}
+
+int
+xfs_ag_shrink_space(
+	struct xfs_perag	*pag,
+	struct xfs_trans	**tpp,
+	xfs_extlen_t		delta)
+{
+	struct xfs_mount	*mp = pag->pag_mount;
+	struct xfs_alloc_arg	args = {
+		.tp	= *tpp,
+		.mp	= mp,
+		.type	= XFS_ALLOCTYPE_THIS_BNO,
+		.minlen = delta,
+		.maxlen = delta,
+		.oinfo	= XFS_RMAP_OINFO_SKIP_UPDATE,
+		.resv	= XFS_AG_RESV_NONE,
+		.prod	= 1
+	};
+	struct xfs_buf		*agibp, *agfbp;
+	struct xfs_agi		*agi;
+	struct xfs_agf		*agf;
+	xfs_agblock_t		aglen;
+	int			error, err2;
+
+	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(pag, *tpp, 0, &agfbp);
+	if (error)
+		return error;
+
+	agf = agfbp->b_addr;
+	aglen = be32_to_cpu(agi->agi_length);
+	/* some extra paranoid checks before we shrink the ag */
+	if (XFS_IS_CORRUPT(mp, agf->agf_length != agi->agi_length))
+		return -EFSCORRUPTED;
+	if (delta >= aglen)
+		return -EINVAL;
+
+	args.fsbno = XFS_AGB_TO_FSB(mp, pag->pag_agno, aglen - delta);
+
+	/*
+	 * Make sure that the last inode cluster cannot overlap with the new
+	 * end of the AG, even if it's sparse.
+	 */
+	error = xfs_ialloc_check_shrink(*tpp, pag->pag_agno, agibp,
+			aglen - delta);
+	if (error)
+		return error;
+
+	/*
+	 * 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(pag);
+	if (error)
+		return error;
+
+	/* internal log shouldn't also show up in the free space btrees */
+	error = xfs_alloc_vextent(&args);
+	if (!error && args.agbno == NULLAGBLOCK)
+		error = -ENOSPC;
+
+	if (error) {
+		/*
+		 * if extent allocation fails, need to roll the transaction to
+		 * ensure that the AGFL fixup has been committed anyway.
+		 */
+		xfs_trans_bhold(*tpp, agfbp);
+		err2 = xfs_trans_roll(tpp);
+		if (err2)
+			return err2;
+		xfs_trans_bjoin(*tpp, agfbp);
+		goto resv_init_out;
+	}
+
+	/*
+	 * if successfully deleted from freespace btrees, need to confirm
+	 * per-AG reservation works as expected.
+	 */
+	be32_add_cpu(&agi->agi_length, -delta);
+	be32_add_cpu(&agf->agf_length, -delta);
+
+	err2 = xfs_ag_resv_init(pag, *tpp);
+	if (err2) {
+		be32_add_cpu(&agi->agi_length, delta);
+		be32_add_cpu(&agf->agf_length, delta);
+		if (err2 != -ENOSPC)
+			goto resv_err;
+
+		__xfs_free_extent_later(*tpp, args.fsbno, delta, NULL, true);
+
+		/*
+		 * Roll the transaction before trying to re-init the per-ag
+		 * reservation. The new transaction is clean so it will cancel
+		 * without any side effects.
+		 */
+		error = xfs_defer_finish(tpp);
+		if (error)
+			return error;
+
+		error = -ENOSPC;
+		goto resv_init_out;
+	}
+	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(pag, *tpp);
+	if (!err2)
+		return error;
+resv_err:
+	xfs_warn(mp, "Error %d reserving per-AG metadata reserve pool.", err2);
+	xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
+	return err2;
+}
+
+/*
+ * Extent the AG indicated by the @id by the length passed in
+ */
+int
+xfs_ag_extend_space(
+	struct xfs_perag	*pag,
+	struct xfs_trans	*tp,
+	xfs_extlen_t		len)
+{
+	struct xfs_buf		*bp;
+	struct xfs_agi		*agi;
+	struct xfs_agf		*agf;
+	int			error;
+
+	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);
+	xfs_ialloc_log_agi(tp, bp, XFS_AGI_LENGTH);
+
+	/*
+	 * Change agf length.
+	 */
+	error = xfs_alloc_read_agf(pag, tp, 0, &bp);
+	if (error)
+		return error;
+
+	agf = bp->b_addr;
+	be32_add_cpu(&agf->agf_length, len);
+	ASSERT(agf->agf_length == agi->agi_length);
+	xfs_alloc_log_agf(tp, bp, XFS_AGF_LENGTH);
+
+	/*
+	 * Free the new 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, pag, be32_to_cpu(agf->agf_length) - len,
+				len, &XFS_RMAP_OINFO_SKIP_UPDATE);
+	if (error)
+		return error;
+
+	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_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;
+	unsigned int		freeblks;
+	int			error;
+
+	/* Lock the AG headers. */
+	error = xfs_ialloc_read_agi(pag, NULL, &agi_bp);
+	if (error)
+		return error;
+	error = xfs_alloc_read_agf(pag, NULL, 0, &agf_bp);
+	if (error)
+		goto out_agi;
+
+	/* Fill out form. */
+	memset(ageo, 0, sizeof(*ageo));
+	ageo->ag_number = pag->pag_agno;
+
+	agi = agi_bp->b_addr;
+	ageo->ag_icount = be32_to_cpu(agi->agi_count);
+	ageo->ag_ifree = be32_to_cpu(agi->agi_freecount);
+
+	agf = agf_bp->b_addr;
+	ageo->ag_length = be32_to_cpu(agf->agf_length);
+	freeblks = pag->pagf_freeblks +
+		   pag->pagf_flcount +
+		   pag->pagf_btreeblks -
+		   xfs_ag_resv_needed(pag, XFS_AG_RESV_NONE);
+	ageo->ag_freeblks = freeblks;
+	xfs_ag_geom_health(pag, ageo);
+
+	/* Release resources. */
+	xfs_buf_relse(agf_bp);
+out_agi:
+	xfs_buf_relse(agi_bp);
+	return error;
+}