xfs: add metadata reservations for realtime refcount btree

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 <djwong@kernel.org>

diff --git a/libxfs/xfs_rtrefcount_btree.c b/libxfs/xfs_rtrefcount_btree.c
index 067b4aaeb5ce58a1c2ad7475be9c8328ae150c6d..4547614341c47b461deace7a752811f8cc2545d3 100644 (file)
--- a/libxfs/xfs_rtrefcount_btree.c
+++ b/libxfs/xfs_rtrefcount_btree.c
@@ -420,3 +420,41 @@ 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 b713b33818800c66a1879e56f8245d975e99defe..3cd44590c9304c599acba0d7cf216d16120ae225 100644 (file)
--- 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__ */