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 95c3f0cd9081bae0dc30e13fcd004d8a4765e03f..196ae8b48357a2a2c35fac59bd54f8150d7fa157 100644 (file)
--- 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 a149ab77453053f17ba88554ab7000a8e4a3436f..064f37334a9a7b1a89b67f1c743a77d97c572799 100644 (file)
--- 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__ */