1 files changed, 9 insertions, 0 deletions

diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c
index 5738e11055e6..5d1f8884c888 100644
--- a/fs/xfs/libxfs/xfs_rmap_btree.c
+++ b/fs/xfs/libxfs/xfs_rmap_btree.c
@@ -578,6 +578,15 @@ xfs_rmapbt_calc_reserves(
         tree_len = be32_to_cpu(agf->agf_rmap_blocks);
         xfs_trans_brelse(tp, agbp);
 
+        /*
+         * The log is permanently allocated, so the space it occupies will
+         * never be available for the kinds of things that would require btree
+         * expansion.  We therefore can pretend the space isn't there.
+         */
+        if (mp->m_sb.sb_logstart &&
+            XFS_FSB_TO_AGNO(mp, mp->m_sb.sb_logstart) == agno)
+                agblocks -= mp->m_sb.sb_logblocks;
+
         /* Reserve 1% of the AG or enough for 1 block per record. */
         *ask += max(agblocks / 100, xfs_rmapbt_max_size(mp, agblocks));
         *used += tree_len;