[38/56] xfs: add metadata reservations for realtime refcount btree

Commit Message

Darrick J. Wong Feb. 6, 2025, 10:45 p.m. UTC

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

Source kernel commit: bf0b99411335db18a9ed4fcef278ce9e313f6076

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]>
Reviewed-by: Christoph Hellwig <[e-mail]>
---
 libxfs/xfs_rtrefcount_btree.c |   38 ++++++++++++++++++++++++++++++++++++++
 libxfs/xfs_rtrefcount_btree.h |    4 ++++
 2 files changed, 42 insertions(+)

Patch

diff --git a/libxfs/xfs_rtrefcount_btree.c b/libxfs/xfs_rtrefcount_btree.c
index 46c62bd63458f4..9fa8f1d6eb6749 100644
--- a/libxfs/xfs_rtrefcount_btree.c
+++ b/libxfs/xfs_rtrefcount_btree.c
@@ -417,3 +417,41 @@  xfs_rtrefcountbt_compute_maxlevels(
 	/* Add one level to handle the inode root level. */
 	mp->m_rtrefc_maxlevels = min(d_maxlevels, r_maxlevels) + 1;
 }
+
+/* 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, mp->m_sb.sb_rgextents);
+}
diff --git a/libxfs/xfs_rtrefcount_btree.h b/libxfs/xfs_rtrefcount_btree.h
index b713b33818800c..3cd44590c9304c 100644
--- a/libxfs/xfs_rtrefcount_btree.h
+++ b/libxfs/xfs_rtrefcount_btree.h
@@ -67,4 +67,8 @@  unsigned int xfs_rtrefcountbt_maxlevels_ondisk(void);
 int __init xfs_rtrefcountbt_init_cur_cache(void);
 void xfs_rtrefcountbt_destroy_cur_cache(void);
 
+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__ */