1 files changed, 12 insertions, 3 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 3158817cd5a9..81aa7cf3ae86 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3677,6 +3677,7 @@ static int can_overcommit(struct btrfs_root *root,
         u64 rsv_size = 0;
         u64 avail;
         u64 used;
+        u64 to_add;
 
         used = space_info->bytes_used + space_info->bytes_reserved +
                 space_info->bytes_pinned + space_info->bytes_readonly;
@@ -3710,17 +3711,25 @@ static int can_overcommit(struct btrfs_root *root,
                        BTRFS_BLOCK_GROUP_RAID10))
                 avail >>= 1;
 
+        to_add = space_info->total_bytes;
+
         /*
          * If we aren't flushing all things, let us overcommit up to
          * 1/2th of the space. If we can flush, don't let us overcommit
          * too much, let it overcommit up to 1/8 of the space.
          */
         if (flush == BTRFS_RESERVE_FLUSH_ALL)
-                avail >>= 3;
+                to_add >>= 3;
         else
-                avail >>= 1;
+                to_add >>= 1;
+
+        /*
+         * Limit the overcommit to the amount of free space we could possibly
+         * allocate for chunks.
+         */
+        to_add = min(avail, to_add);
 
-        if (used + bytes < space_info->total_bytes + avail)
+        if (used + bytes < space_info->total_bytes + to_add)
                 return 1;
         return 0;
 }