800  * are split.
807 	struct extent_map *split;  in btrfs_drop_extent_map_range()  local
831 	 * because we need to split those two extent maps at the boundaries.  in btrfs_drop_extent_map_range()
833 	split = alloc_extent_map();  in btrfs_drop_extent_map_range()
864 		 * In case we split the extent map, we want to preserve the  in btrfs_drop_extent_map_range()
873 		 * split it, we can remove it directly.  in btrfs_drop_extent_map_range()
881 			if (!split) {  in btrfs_drop_extent_map_range()
882 				split = split2;  in btrfs_drop_extent_map_range()
884 				if (!split)  in btrfs_drop_extent_map_range()
887 			split->start = em->start;  in btrfs_drop_extent_map_range()
888 			split->len = start - em->start;  in btrfs_drop_extent_map_range()
891 				split->disk_bytenr = em->disk_bytenr;  in btrfs_drop_extent_map_range()
892 				split->disk_num_bytes = em->disk_num_bytes;  in btrfs_drop_extent_map_range()
893 				split->offset = em->offset;  in btrfs_drop_extent_map_range()
894 				split->ram_bytes = em->ram_bytes;  in btrfs_drop_extent_map_range()
896 				split->disk_bytenr = em->disk_bytenr;  in btrfs_drop_extent_map_range()
897 				split->disk_num_bytes = 0;  in btrfs_drop_extent_map_range()
898 				split->offset = 0;  in btrfs_drop_extent_map_range()
899 				split->ram_bytes = split->len;  in btrfs_drop_extent_map_range()
902 			split->generation = gen;  in btrfs_drop_extent_map_range()
903 			split->flags = flags;  in btrfs_drop_extent_map_range()
904 			replace_extent_mapping(inode, em, split, modified);  in btrfs_drop_extent_map_range()
905 			free_extent_map(split);  in btrfs_drop_extent_map_range()
906 			split = split2;  in btrfs_drop_extent_map_range()
910 			if (!split) {  in btrfs_drop_extent_map_range()
911 				split = split2;  in btrfs_drop_extent_map_range()
913 				if (!split)  in btrfs_drop_extent_map_range()
916 			split->start = end;  in btrfs_drop_extent_map_range()
917 			split->len = em_end - end;  in btrfs_drop_extent_map_range()
918 			split->disk_bytenr = em->disk_bytenr;  in btrfs_drop_extent_map_range()
919 			split->flags = flags;  in btrfs_drop_extent_map_range()
920 			split->generation = gen;  in btrfs_drop_extent_map_range()
923 				split->disk_num_bytes = em->disk_num_bytes;  in btrfs_drop_extent_map_range()
924 				split->offset = em->offset + end - em->start;  in btrfs_drop_extent_map_range()
925 				split->ram_bytes = em->ram_bytes;  in btrfs_drop_extent_map_range()
927 				split->disk_num_bytes = 0;  in btrfs_drop_extent_map_range()
928 				split->offset = 0;  in btrfs_drop_extent_map_range()
929 				split->ram_bytes = split->len;  in btrfs_drop_extent_map_range()
933 				replace_extent_mapping(inode, em, split, modified);  in btrfs_drop_extent_map_range()
937 				ret = add_extent_mapping(inode, split, modified);  in btrfs_drop_extent_map_range()
943 			free_extent_map(split);  in btrfs_drop_extent_map_range()
944 			split = NULL;  in btrfs_drop_extent_map_range()
957 			 *    maps for split operations, @split and @split2.  in btrfs_drop_extent_map_range()
969 				ASSERT(!split);  in btrfs_drop_extent_map_range()
989 	free_extent_map(split);  in btrfs_drop_extent_map_range()
1035  * Split off the first pre bytes from the extent_map at [start, start + len],
1038  * This function is used when an ordered_extent needs to be split.