From: Darrick J. Wong <djwong@xxxxxxxxxx>
Reserve some free blocks so that we will always have enough free blocks
in the data volume to handle expansion of the realtime rmap btree.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
libxfs/xfs_rtrmap_btree.c | 39 +++++++++++++++++++++++++++++++++++++++
libxfs/xfs_rtrmap_btree.h | 2 ++
2 files changed, 41 insertions(+)
diff --git a/libxfs/xfs_rtrmap_btree.c b/libxfs/xfs_rtrmap_btree.c
index 85608c813b4..d45f711ce06 100644
--- a/libxfs/xfs_rtrmap_btree.c
+++ b/libxfs/xfs_rtrmap_btree.c
@@ -606,3 +606,42 @@ xfs_rtrmapbt_create_path(
*pathp = path;
return 0;
}
+
+/* Calculate the rtrmap btree size for some records. */
+static unsigned long long
+xfs_rtrmapbt_calc_size(
+ struct xfs_mount *mp,
+ unsigned long long len)
+{
+ return xfs_btree_calc_size(mp->m_rtrmap_mnr, len);
+}
+
+/*
+ * Calculate the maximum rmap btree size.
+ */
+static unsigned long long
+xfs_rtrmapbt_max_size(
+ struct xfs_mount *mp,
+ xfs_rtblock_t rtblocks)
+{
+ /* Bail out if we're uninitialized, which can happen in mkfs. */
+ if (mp->m_rtrmap_mxr[0] == 0)
+ return 0;
+
+ return xfs_rtrmapbt_calc_size(mp, rtblocks);
+}
+
+/*
+ * Figure out how many blocks to reserve and how many are used by this btree.
+ */
+xfs_filblks_t
+xfs_rtrmapbt_calc_reserves(
+ struct xfs_mount *mp)
+{
+ if (!xfs_has_rtrmapbt(mp))
+ return 0;
+
+ /* 1/64th (~1.5%) of the space, and enough for 1 record per block. */
+ return max_t(xfs_filblks_t, mp->m_sb.sb_rgblocks >> 6,
+ xfs_rtrmapbt_max_size(mp, mp->m_sb.sb_rgblocks));
+}
diff --git a/libxfs/xfs_rtrmap_btree.h b/libxfs/xfs_rtrmap_btree.h
index 26e2445f5d6..63e667d0d76 100644
--- a/libxfs/xfs_rtrmap_btree.h
+++ b/libxfs/xfs_rtrmap_btree.h
@@ -84,4 +84,6 @@ void xfs_rtrmapbt_destroy_cur_cache(void);
int xfs_rtrmapbt_create_path(struct xfs_mount *mp, xfs_rgnumber_t rgno,
struct xfs_imeta_path **pathp);
+xfs_filblks_t xfs_rtrmapbt_calc_reserves(struct xfs_mount *mp);
+
#endif /* __XFS_RTRMAP_BTREE_H__ */
