struct btrfs_space_info {
        u64 flags;
 
-       u64 total_bytes;        /* total bytes in the space */
+       u64 total_bytes;        /* total bytes in the space,
+                                  this doesn't take mirrors into account */
        u64 bytes_used;         /* total bytes used,
                                   this does't take mirrors into account */
        u64 bytes_pinned;       /* total bytes pinned, will be freed when the
        u64 bytes_may_use;      /* number of bytes that may be used for
                                   delalloc/allocations */
        u64 disk_used;          /* total bytes used on disk */
+       u64 disk_total;         /* total bytes on disk, takes mirrors into
+                                  account */
 
        int full;               /* indicates that we cannot allocate any more
                                   chunks for this space */
 
        if (found) {
                spin_lock(&found->lock);
                found->total_bytes += total_bytes;
+               found->disk_total += total_bytes * factor;
                found->bytes_used += bytes_used;
                found->disk_used += bytes_used * factor;
                found->full = 0;
                                BTRFS_BLOCK_GROUP_SYSTEM |
                                BTRFS_BLOCK_GROUP_METADATA);
        found->total_bytes = total_bytes;
+       found->disk_total = total_bytes * factor;
        found->bytes_used = bytes_used;
        found->disk_used = bytes_used * factor;
        found->bytes_pinned = 0;
        struct btrfs_free_cluster *cluster;
        struct btrfs_key key;
        int ret;
+       int factor;
 
        root = root->fs_info->extent_root;
 
        BUG_ON(!block_group->ro);
 
        memcpy(&key, &block_group->key, sizeof(key));
+       if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
+                                 BTRFS_BLOCK_GROUP_RAID1 |
+                                 BTRFS_BLOCK_GROUP_RAID10))
+               factor = 2;
+       else
+               factor = 1;
 
        /* make sure this block group isn't part of an allocation cluster */
        cluster = &root->fs_info->data_alloc_cluster;
        spin_lock(&block_group->space_info->lock);
        block_group->space_info->total_bytes -= block_group->key.offset;
        block_group->space_info->bytes_readonly -= block_group->key.offset;
+       block_group->space_info->disk_total -= block_group->key.offset * factor;
        spin_unlock(&block_group->space_info->lock);
 
        btrfs_clear_space_info_full(root->fs_info);
 
        struct list_head *head = &root->fs_info->space_info;
        struct btrfs_space_info *found;
        u64 total_used = 0;
+       u64 total_used_data = 0;
        int bits = dentry->d_sb->s_blocksize_bits;
        __be32 *fsid = (__be32 *)root->fs_info->fsid;
 
        rcu_read_lock();
-       list_for_each_entry_rcu(found, head, list)
+       list_for_each_entry_rcu(found, head, list) {
+               if (found->flags & (BTRFS_BLOCK_GROUP_METADATA |
+                                   BTRFS_BLOCK_GROUP_SYSTEM))
+                       total_used_data += found->disk_total;
+               else
+                       total_used_data += found->disk_used;
                total_used += found->disk_used;
+       }
        rcu_read_unlock();
 
        buf->f_namelen = BTRFS_NAME_LEN;
        buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
        buf->f_bfree = buf->f_blocks - (total_used >> bits);
-       buf->f_bavail = buf->f_bfree;
+       buf->f_bavail = buf->f_blocks - (total_used_data >> bits);
        buf->f_bsize = dentry->d_sb->s_blocksize;
        buf->f_type = BTRFS_SUPER_MAGIC;