+ max_avail = devices[0].max_avail;
+ if (!max_avail)
+ return -ENOSPC;
+
+ for (i = 0; i < nr_device; i++) {
+ /*
+ * if dev_offset = 0, it means the free space of this device
+ * is less than what we need, and we didn't search max avail
+ * extent on this device, so do it now.
+ */
+ if (!devices[i].dev_offset) {
+ ret = find_free_dev_extent(trans, devices[i].dev,
+ max_avail,
+ &devices[i].dev_offset,
+ &devices[i].max_avail);
+ if (ret != 0 && ret != -ENOSPC)
+ return ret;
+ sort_again = 1;
+ }
+ }
+
+ /* we update the max avail free extent of each devices, sort again */
+ if (sort_again)
+ btrfs_descending_sort_devices(devices, nr_device);
+
+ if (type & BTRFS_BLOCK_GROUP_DUP)
+ min_devices = 1;
+
+ if (!devices[min_devices - 1].max_avail)
+ return -ENOSPC;
+
+ max_avail = devices[min_devices - 1].max_avail;
+ if (type & BTRFS_BLOCK_GROUP_DUP)
+ do_div(max_avail, 2);
+
+ max_avail = __btrfs_calc_stripe_size(fs_devices, max_avail, type,
+ min_stripes, 1);
+ if (type & BTRFS_BLOCK_GROUP_DUP)
+ min_free = max_avail * 2;
+ else
+ min_free = max_avail;
+
+ if (min_free > devices[min_devices - 1].max_avail)
+ return -ENOSPC;
+
+ map = __shrink_map_lookup_stripes(map, min_stripes);
+ *stripe_size = max_avail;
+
+ index = 0;
+ for (i = 0; i < min_stripes; i++) {
+ map->stripes[i].dev = devices[index].dev;
+ map->stripes[i].physical = devices[index].dev_offset;
+ if (type & BTRFS_BLOCK_GROUP_DUP) {
+ i++;
+ map->stripes[i].dev = devices[index].dev;
+ map->stripes[i].physical = devices[index].dev_offset +
+ max_avail;
+ }
+ index++;
+ }
+ *map_lookup = map;
+
+ return 0;
+}
+
+static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
+ struct btrfs_root *extent_root,
+ struct map_lookup **map_ret,
+ u64 *num_bytes, u64 *stripe_size,
+ u64 start, u64 type)
+{
+ struct btrfs_fs_info *info = extent_root->fs_info;
+ struct btrfs_device *device = NULL;
+ struct btrfs_fs_devices *fs_devices = info->fs_devices;
+ struct list_head *cur;
+ struct map_lookup *map;
+ struct extent_map_tree *em_tree;
+ struct extent_map *em;
+ struct btrfs_device_info *devices_info;
+ struct list_head private_devs;
+ u64 calc_size = 1024 * 1024 * 1024;
+ u64 min_free;
+ u64 avail;
+ u64 dev_offset;
+ int num_stripes;
+ int min_stripes;
+ int sub_stripes;
+ int min_devices; /* the min number of devices we need */
+ int i;
+ int ret;
+ int index;
+
+ if ((type & BTRFS_BLOCK_GROUP_RAID1) &&
+ (type & BTRFS_BLOCK_GROUP_DUP)) {
+ WARN_ON(1);
+ type &= ~BTRFS_BLOCK_GROUP_DUP;
+ }
+ if (list_empty(&fs_devices->alloc_list))
+ return -ENOSPC;
+
+ ret = __btrfs_calc_nstripes(fs_devices, type, &num_stripes,
+ &min_stripes, &sub_stripes);
+ if (ret)
+ return ret;
+
+ devices_info = kzalloc(sizeof(*devices_info) * fs_devices->rw_devices,
+ GFP_NOFS);
+ if (!devices_info)
+ return -ENOMEM;
+
+ map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
+ if (!map) {
+ ret = -ENOMEM;
+ goto error;
+ }
+ map->num_stripes = num_stripes;