From 2a39946c984464e4aac82c556ba9915589be7323 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <darrick.wong@oracle.com>
Date: Mon, 17 Aug 2020 09:58:01 -0700
Subject: [PATCH] xfs: store inode btree block counts in AGI header
Git-commit: 2a39946c984464e4aac82c556ba9915589be7323
Patch-mainline: v5.10-rc1
References: bsc#1203387

Add a btree block usage counters for both inode btrees to the AGI header
so that we don't have to walk the entire finobt at mount time to create
the per-AG reservations.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Acked-by: Anthony Iliopoulos <ailiop@suse.com>

---
 fs/xfs/libxfs/xfs_ag.c           |    5 +++++
 fs/xfs/libxfs/xfs_format.h       |   18 +++++++++++++++++-
 fs/xfs/libxfs/xfs_ialloc.c       |    1 +
 fs/xfs/libxfs/xfs_ialloc_btree.c |   21 +++++++++++++++++++++
 fs/xfs/xfs_ondisk.h              |    2 +-
 fs/xfs/xfs_super.c               |    4 ++++
 6 files changed, 49 insertions(+), 2 deletions(-)

--- a/fs/xfs/libxfs/xfs_ag.c
+++ b/fs/xfs/libxfs/xfs_ag.c
@@ -256,6 +256,11 @@ xfs_agiblock_init(
 	}
 	for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
 		agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
+	if (xfs_sb_version_hasinobtcounts(&mp->m_sb)) {
+		agi->agi_iblocks = cpu_to_be32(1);
+		if (xfs_sb_version_hasfinobt(&mp->m_sb))
+			agi->agi_fblocks = cpu_to_be32(1);
+	}
 }
 
 typedef void (*aghdr_init_work_f)(struct xfs_mount *mp, struct xfs_buf *bp,
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -460,6 +460,7 @@ xfs_sb_has_compat_feature(
 #define XFS_SB_FEAT_RO_COMPAT_FINOBT   (1 << 0)		/* free inode btree */
 #define XFS_SB_FEAT_RO_COMPAT_RMAPBT   (1 << 1)		/* reverse map btree */
 #define XFS_SB_FEAT_RO_COMPAT_REFLINK  (1 << 2)		/* reflinked files */
+#define XFS_SB_FEAT_RO_COMPAT_INOBTCNT (1 << 3)		/* inobt block counts */
 #define XFS_SB_FEAT_RO_COMPAT_ALL \
 		(XFS_SB_FEAT_RO_COMPAT_FINOBT | \
 		 XFS_SB_FEAT_RO_COMPAT_RMAPBT | \
@@ -558,6 +559,17 @@ static inline bool xfs_sb_version_hasref
 }
 
 /*
+ * Inode btree block counter.  We record the number of inobt and finobt blocks
+ * in the AGI header so that we can skip the finobt walk at mount time when
+ * setting up per-AG reservations.
+ */
+static inline bool xfs_sb_version_hasinobtcounts(struct xfs_sb *sbp)
+{
+	return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 &&
+		(sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_INOBTCNT);
+}
+
+/*
  * end of superblock version macros
  */
 
@@ -761,6 +773,9 @@ typedef struct xfs_agi {
 	__be32		agi_free_root; /* root of the free inode btree */
 	__be32		agi_free_level;/* levels in free inode btree */
 
+	__be32		agi_iblocks;	/* inobt blocks used */
+	__be32		agi_fblocks;	/* finobt blocks used */
+
 	/* structure must be padded to 64 bit alignment */
 } xfs_agi_t;
 
@@ -781,7 +796,8 @@ typedef struct xfs_agi {
 #define	XFS_AGI_ALL_BITS_R1	((1 << XFS_AGI_NUM_BITS_R1) - 1)
 #define	XFS_AGI_FREE_ROOT	(1 << 11)
 #define	XFS_AGI_FREE_LEVEL	(1 << 12)
-#define	XFS_AGI_NUM_BITS_R2	13
+#define	XFS_AGI_IBLOCKS		(1 << 13) /* both inobt/finobt block counters */
+#define	XFS_AGI_NUM_BITS_R2	14
 
 /* disk block (xfs_daddr_t) in the AG */
 #define XFS_AGI_DADDR(mp)	((xfs_daddr_t)(2 << (mp)->m_sectbb_log))
--- a/fs/xfs/libxfs/xfs_ialloc.c
+++ b/fs/xfs/libxfs/xfs_ialloc.c
@@ -2449,6 +2449,7 @@ xfs_ialloc_log_agi(
 		offsetof(xfs_agi_t, agi_unlinked),
 		offsetof(xfs_agi_t, agi_free_root),
 		offsetof(xfs_agi_t, agi_free_level),
+		offsetof(xfs_agi_t, agi_iblocks),
 		sizeof(xfs_agi_t)
 	};
 #ifdef DEBUG
--- a/fs/xfs/libxfs/xfs_ialloc_btree.c
+++ b/fs/xfs/libxfs/xfs_ialloc_btree.c
@@ -81,6 +81,25 @@ xfs_finobt_set_root(
 			   XFS_AGI_FREE_ROOT | XFS_AGI_FREE_LEVEL);
 }
 
+/* Update the inode btree block counter for this btree. */
+static inline void
+xfs_inobt_mod_blockcount(
+	struct xfs_btree_cur	*cur,
+	int			howmuch)
+{
+	struct xfs_buf		*agbp = cur->bc_private.a.agbp;
+	struct xfs_agi		*agi = agbp->b_addr;
+
+	if (!xfs_sb_version_hasinobtcounts(&cur->bc_mp->m_sb))
+		return;
+
+	if (cur->bc_btnum == XFS_BTNUM_FINO)
+		be32_add_cpu(&agi->agi_fblocks, howmuch);
+	else if (cur->bc_btnum == XFS_BTNUM_INO)
+		be32_add_cpu(&agi->agi_iblocks, howmuch);
+	xfs_ialloc_log_agi(cur->bc_tp, agbp, XFS_AGI_IBLOCKS);
+}
+
 STATIC int
 __xfs_inobt_alloc_block(
 	struct xfs_btree_cur	*cur,
@@ -121,6 +140,7 @@ __xfs_inobt_alloc_block(
 
 	new->s = cpu_to_be32(XFS_FSB_TO_AGBNO(args.mp, args.fsbno));
 	*stat = 1;
+	xfs_inobt_mod_blockcount(cur, 1);
 	return 0;
 }
 
@@ -156,6 +176,7 @@ __xfs_inobt_free_block(
 	struct xfs_owner_info	oinfo;
 
 	xfs_rmap_ag_owner(&oinfo, XFS_RMAP_OWN_INOBT);
+	xfs_inobt_mod_blockcount(cur, -1);
 	return xfs_free_extent(cur->bc_tp,
 			XFS_DADDR_TO_FSB(cur->bc_mp, XFS_BUF_ADDR(bp)), 1,
 			&oinfo, resv);
--- a/fs/xfs/xfs_ondisk.h
+++ b/fs/xfs/xfs_ondisk.h
@@ -35,7 +35,7 @@ xfs_check_ondisk_structs(void)
 	XFS_CHECK_STRUCT_SIZE(struct xfs_acl_entry,		12);
 	XFS_CHECK_STRUCT_SIZE(struct xfs_agf,			224);
 	XFS_CHECK_STRUCT_SIZE(struct xfs_agfl,			36);
-	XFS_CHECK_STRUCT_SIZE(struct xfs_agi,			336);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_agi,			344);
 	XFS_CHECK_STRUCT_SIZE(struct xfs_bmbt_key,		8);
 	XFS_CHECK_STRUCT_SIZE(struct xfs_bmbt_rec,		16);
 	XFS_CHECK_STRUCT_SIZE(struct xfs_bmdr_block,		4);
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1675,6 +1675,10 @@ xfs_fs_fill_super(
 		xfs_alert(mp,
 	"EXPERIMENTAL reflink feature enabled. Use at your own risk!");
 
+	if (xfs_sb_version_hasinobtcounts(&mp->m_sb))
+		xfs_warn(mp,
+ "EXPERIMENTAL inode btree counters feature in use. Use at your own risk!");
+
 	error = xfs_mountfs(mp);
 	if (error)
 		goto out_filestream_unmount;