703  * are split.
710 	struct extent_map *split;  in btrfs_drop_extent_map_range()  local
734 	 * because we need to split those two extent maps at the boundaries.  in btrfs_drop_extent_map_range()
736 	split = alloc_extent_map();  in btrfs_drop_extent_map_range()
769 		 * In case we split the extent map, we want to preserve the  in btrfs_drop_extent_map_range()
778 		 * split it, we can remove it directly.  in btrfs_drop_extent_map_range()
787 			if (!split) {  in btrfs_drop_extent_map_range()
788 				split = split2;  in btrfs_drop_extent_map_range()
790 				if (!split)  in btrfs_drop_extent_map_range()
793 			split->start = em->start;  in btrfs_drop_extent_map_range()
794 			split->len = start - em->start;  in btrfs_drop_extent_map_range()
797 				split->orig_start = em->orig_start;  in btrfs_drop_extent_map_range()
798 				split->block_start = em->block_start;  in btrfs_drop_extent_map_range()
801 					split->block_len = em->block_len;  in btrfs_drop_extent_map_range()
803 					split->block_len = split->len;  in btrfs_drop_extent_map_range()
804 				split->orig_block_len = max(split->block_len,  in btrfs_drop_extent_map_range()
806 				split->ram_bytes = em->ram_bytes;  in btrfs_drop_extent_map_range()
808 				split->orig_start = split->start;  in btrfs_drop_extent_map_range()
809 				split->block_len = 0;  in btrfs_drop_extent_map_range()
810 				split->block_start = em->block_start;  in btrfs_drop_extent_map_range()
811 				split->orig_block_len = 0;  in btrfs_drop_extent_map_range()
812 				split->ram_bytes = split->len;  in btrfs_drop_extent_map_range()
815 			split->generation = gen;  in btrfs_drop_extent_map_range()
816 			split->flags = flags;  in btrfs_drop_extent_map_range()
817 			split->compress_type = em->compress_type;  in btrfs_drop_extent_map_range()
818 			replace_extent_mapping(em_tree, em, split, modified);  in btrfs_drop_extent_map_range()
819 			free_extent_map(split);  in btrfs_drop_extent_map_range()
820 			split = split2;  in btrfs_drop_extent_map_range()
824 			if (!split) {  in btrfs_drop_extent_map_range()
825 				split = split2;  in btrfs_drop_extent_map_range()
827 				if (!split)  in btrfs_drop_extent_map_range()
830 			split->start = end;  in btrfs_drop_extent_map_range()
831 			split->len = em_end - end;  in btrfs_drop_extent_map_range()
832 			split->block_start = em->block_start;  in btrfs_drop_extent_map_range()
833 			split->flags = flags;  in btrfs_drop_extent_map_range()
834 			split->compress_type = em->compress_type;  in btrfs_drop_extent_map_range()
835 			split->generation = gen;  in btrfs_drop_extent_map_range()
838 				split->orig_block_len = max(em->block_len,  in btrfs_drop_extent_map_range()
841 				split->ram_bytes = em->ram_bytes;  in btrfs_drop_extent_map_range()
843 					split->block_len = em->block_len;  in btrfs_drop_extent_map_range()
844 					split->orig_start = em->orig_start;  in btrfs_drop_extent_map_range()
848 					split->block_len = split->len;  in btrfs_drop_extent_map_range()
849 					split->block_start += diff;  in btrfs_drop_extent_map_range()
850 					split->orig_start = em->orig_start;  in btrfs_drop_extent_map_range()
853 				split->ram_bytes = split->len;  in btrfs_drop_extent_map_range()
854 				split->orig_start = split->start;  in btrfs_drop_extent_map_range()
855 				split->block_len = 0;  in btrfs_drop_extent_map_range()
856 				split->orig_block_len = 0;  in btrfs_drop_extent_map_range()
860 				replace_extent_mapping(em_tree, em, split,  in btrfs_drop_extent_map_range()
865 				ret = add_extent_mapping(em_tree, split,  in btrfs_drop_extent_map_range()
872 			free_extent_map(split);  in btrfs_drop_extent_map_range()
873 			split = NULL;  in btrfs_drop_extent_map_range()
886 			 *    maps for split operations, @split and @split2.  in btrfs_drop_extent_map_range()
898 				ASSERT(!split);  in btrfs_drop_extent_map_range()
918 	free_extent_map(split);  in btrfs_drop_extent_map_range()
964  * Split off the first pre bytes from the extent_map at [start, start + len],
967  * This function is used when an ordered_extent needs to be split.