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 27a444182cf5a398c84214ed4ae548590277ba33..97ecc0d74ec982b36d3a2edf6950e966c2754edc 100644 (file)
--- a/libxfs/xfs_rtrefcount_btree.c
+++ b/libxfs/xfs_rtrefcount_btree.c
@@ -422,3 +422,42 @@ 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,
+                       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 f617cd43a3d409da2a95c30191f375da1142a8fc..d5251bb7b578f4335e23c4140cba10969aad72f7 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);
 #define xfs_rtrefcountbt_create_path(mp, rgno) \
        xfs_rtinode_create_path((mp), (rgno), "refcount")
 
+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__ */