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 33399260045dd8b7e192a8fac6bc7971f7b50dfc..4defa97aba5b9ced6b14af8fcb8976846d15c40d 100644 (file)
--- a/libxfs/xfs_rtrefcount_btree.c
+++ b/libxfs/xfs_rtrefcount_btree.c
@@ -423,3 +423,41 @@ 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 6d23ab3a9ad4156de84d5f2cf622f1ce61bae181..d1662f870f1c573f76fbf303e40bef6d7f1728ae 100644 (file)
--- a/libxfs/xfs_rtrefcount_btree.h
+++ b/libxfs/xfs_rtrefcount_btree.h
@@ -68,4 +68,8 @@ 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__ */