Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit e6b5859c authored by Tristan Ye's avatar Tristan Ye
Browse files

Ocfs2/move_extents: helper to probe a proper region to move in an alloc group. 



Before doing the movement of extents, we'd better probe the alloc group from
'goal_blk' for searching a contiguous region to fit the wanted movement, we
even will have a best-effort try by compromising to a threshold around the
given goal.

Signed-off-by: default avatarTristan Ye <tristan.ye@oracle.com>
parent 99e4c750

fs/ocfs2/move_extents.c

+39 −0
Original line number Diff line number Diff line
@@ -516,3 +516,42 @@ out: 


	return ret;

}



static void ocfs2_probe_alloc_group(struct inode *inode, struct buffer_head *bh,

				    int *goal_bit, u32 move_len, u32 max_hop,

				    u32 *phys_cpos)

{

	int i, used, last_free_bits = 0, base_bit = *goal_bit;

	struct ocfs2_group_desc *gd = (struct ocfs2_group_desc *)bh->b_data;

	u32 base_cpos = ocfs2_blocks_to_clusters(inode->i_sb,

						 le64_to_cpu(gd->bg_blkno));



	for (i = base_bit; i < le16_to_cpu(gd->bg_bits); i++) {



		used = ocfs2_test_bit(i, (unsigned long *)gd->bg_bitmap);

		if (used) {

			/*

			 * we even tried searching the free chunk by jumping

			 * a 'max_hop' distance, but still failed.

			 */

			if ((i - base_bit) > max_hop) {

				*phys_cpos = 0;

				break;

			}



			if (last_free_bits)

				last_free_bits = 0;



			continue;

		} else

			last_free_bits++;



		if (last_free_bits == move_len) {

			*goal_bit = i;

			*phys_cpos = base_cpos + i;

			break;

		}

	}



	mlog(0, "found phys_cpos: %u to fit the wanted moving.\n", *phys_cpos);

}