1 files changed, 6 insertions, 0 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 9183f9cbc121..d8da538d01fb 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4034,6 +4034,8 @@ static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
         return nr;
 }
 
+#define EXTENT_SIZE_PER_ITEM    (256 * 1024)
+
 /*
  * shrink metadata reservation for delalloc
  */
@@ -4050,6 +4052,10 @@ static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
         int loops;
         enum btrfs_reserve_flush_enum flush;
 
+        /* Calc the number of the pages we need flush for space reservation */
+        to_reclaim = calc_reclaim_items_nr(root, to_reclaim);
+        to_reclaim *= EXTENT_SIZE_PER_ITEM;
+
         trans = (struct btrfs_trans_handle *)current->journal_info;
         block_rsv = &root->fs_info->delalloc_block_rsv;
         space_info = block_rsv->space_info;