[09/42] xfs: add metadata reservations for realtime refcount btree

Commit Message

Darrick J. Wong Dec. 27, 2023, 1:28 p.m. UTC

From: Darrick J. Wong <[e-mail]>

Reserve some free blocks so that we will always have enough free blocks
in the data volume to handle expansion of the realtime refcount btree.

Signed-off-by: Darrick J. Wong <[e-mail]>
---
 libxfs/xfs_rtrefcount_btree.c |   39 +++++++++++++++++++++++++++++++++++++++
 libxfs/xfs_rtrefcount_btree.h |    4 ++++
 2 files changed, 43 insertions(+)

Patch

diff --git a/libxfs/xfs_rtrefcount_btree.c b/libxfs/xfs_rtrefcount_btree.c
index 425a56578c6..99eac508cda 100644
--- a/libxfs/xfs_rtrefcount_btree.c
+++ b/libxfs/xfs_rtrefcount_btree.c
@@ -489,3 +489,42 @@  xfs_rtrefcountbt_create_path(
 	*pathp = path;
 	return 0;
 }
+
+/* Calculate the rtrefcount btree size for some records. */
+unsigned long long
+xfs_rtrefcountbt_calc_size(
+	struct xfs_mount	*mp,
+	unsigned long long	len)
+{
+	return xfs_btree_calc_size(mp->m_rtrefc_mnr, len);
+}
+
+/*
+ * Calculate the maximum refcount btree size.
+ */
+static unsigned long long
+xfs_rtrefcountbt_max_size(
+	struct xfs_mount	*mp,
+	xfs_rtblock_t		rtblocks)
+{
+	/* Bail out if we're uninitialized, which can happen in mkfs. */
+	if (mp->m_rtrefc_mxr[0] == 0)
+		return 0;
+
+	return xfs_rtrefcountbt_calc_size(mp, rtblocks);
+}
+
+/*
+ * Figure out how many blocks to reserve and how many are used by this btree.
+ * We need enough space to hold one record for every rt extent in the rtgroup.
+ */
+xfs_filblks_t
+xfs_rtrefcountbt_calc_reserves(
+	struct xfs_mount	*mp)
+{
+	if (!xfs_has_rtreflink(mp))
+		return 0;
+
+	return xfs_rtrefcountbt_max_size(mp,
+			xfs_rtb_to_rtx(mp, mp->m_sb.sb_rgblocks));
+}
diff --git a/libxfs/xfs_rtrefcount_btree.h b/libxfs/xfs_rtrefcount_btree.h
index ff49e95d1a4..045f7b1f728 100644
--- a/libxfs/xfs_rtrefcount_btree.h
+++ b/libxfs/xfs_rtrefcount_btree.h
@@ -72,4 +72,8 @@  void xfs_rtrefcountbt_destroy_cur_cache(void);
 int xfs_rtrefcountbt_create_path(struct xfs_mount *mp, xfs_rgnumber_t rgno,
 		struct xfs_imeta_path **pathp);
 
+xfs_filblks_t xfs_rtrefcountbt_calc_reserves(struct xfs_mount *mp);
+unsigned long long xfs_rtrefcountbt_calc_size(struct xfs_mount *mp,
+		unsigned long long len);
+
 #endif	/* __XFS_RTREFCOUNT_BTREE_H__ */