27  * extent tree, whose goal is only track delayed extents in memory to
34  * Currently the first step has been done.  All delayed extents are
35  * tracked in the tree.  It maintains the delayed extent when a delayed
36  * allocation is issued, and the delayed extent is written out or
53  * are under high memory pressure.  Delayed extents will not be
66  * Without extent status tree, ext4 identifies a delayed extent by looking
71  * block or a range of blocks are belonged to a delayed extent.
75  *	FIEMAP looks up page cache to identify delayed allocations from holes.
82  *	already under delayed allocation or not to determine whether
87  *	mapped, If there are not very many delayed buffers, then it is
92  * blocks is under delayed allocation(belonged to a delayed extent) or
112  *	There are three important operations on a delayed extent tree: find
139  *   -- Refactor delayed space reservation
208  * search through the tree for an delayed extent with a given offset.  If
561 	/* we need to check delayed extent */  in ext4_es_can_be_merged()
646 		 * a delayed/hole extent.  in ext4_es_insert_extent_ext_check()
653 					"want to add a delayed/hole extent "  in ext4_es_insert_extent_ext_check()
724 			 * We want to add a delayed/hole extent but this  in ext4_es_insert_extent_ind_check()
729 				"delayed/hole extent [%d/%d/%llu/%x]\n",  in ext4_es_insert_extent_ind_check()
931 	 * allocation of delayed allocated clusters or direct allocation of  in ext4_es_insert_extent()
932 	 * clusters discovered to be delayed allocated.  Once allocated, a  in ext4_es_insert_extent()
937 	 * an extent either 1) contains delayed blocks but start with  in ext4_es_insert_extent()
938 	 * non-delayed allocated blocks (e.g. hole) or 2) contains non-delayed  in ext4_es_insert_extent()
939 	 * allocated blocks which belong to delayed allocated clusters when  in ext4_es_insert_extent()
942 	 * any previously delayed allocated clusters instead of claim them  in ext4_es_insert_extent()
1099 	 * for bigalloc, note the first delayed block in the range has not  in init_rsvd()
1119  * count_rsvd - count the clusters containing delayed blocks in a range
1153 	/* record the first block of the first delayed extent seen */  in count_rsvd()
1185 	 * number of whole delayed clusters in the extent  in count_rsvd()
1249  * clusters containing delayed blocks within the range, minus the number of
1250  * clusters still containing delayed blocks at the ends of the range, and
1277 		 * decrease the delayed count by the number of clusters at the  in get_rsvd()
1278 		 * ends of the range that still contain delayed blocks -  in get_rsvd()
1322 		 * original removed range containing delayed blocks are  in get_rsvd()
1347 		 * delayed block, so the delayed total must be reduced by one  in get_rsvd()
1377  * If @reserved is not NULL and delayed allocation is enabled, counts
2072  * ext4_es_insert_delayed_extent - adds some delayed blocks to the extents
2102 	es_debug("add [%u/%u) delayed to extent status tree of inode %lu\n",  in ext4_es_insert_delayed_extent()
2182  *                    upon the presence or absence of delayed blocks
2215 	 * as if it does not contain a delayed extent.  The new range may  in __revise_pending()
2216 	 * have allocated space for previously delayed blocks out to the  in __revise_pending()