+ if (ret && !check) {
+ u64 profile = btrfs_get_alloc_profile(root, 0);
+ u64 avail;
+
+ spin_lock(&root->fs_info->free_chunk_lock);
+ avail = root->fs_info->free_chunk_space;
+
+ /*
+ * If we have dup, raid1 or raid10 then only half of the free
+ * space is actually useable.
+ */
+ if (profile & (BTRFS_BLOCK_GROUP_DUP |
+ BTRFS_BLOCK_GROUP_RAID1 |
+ BTRFS_BLOCK_GROUP_RAID10))
+ avail >>= 1;
+
+ /*
+ * If we aren't flushing don't let us overcommit too much, say
+ * 1/8th of the space. If we can flush, let it overcommit up to
+ * 1/2 of the space.
+ */
+ if (flush)
+ avail >>= 3;
+ else
+ avail >>= 1;
+ spin_unlock(&root->fs_info->free_chunk_lock);
+
+ if (used + orig_bytes < space_info->total_bytes + avail) {
+ space_info->bytes_may_use += orig_bytes;
+ ret = 0;
+ }
+ }
+