Commit 2a13fc41 authored by Gao Xiang's avatar Gao Xiang
Browse files

erofs: consolidate z_erofs_extent_lookback() 



The initial m.delta[0] also needs to be checked against zero.

In addition, also drop the redundant logic that errors out for
lcn == 0 / m.delta[0] == 1 case.

Signed-off-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
parent e13d315a

fs/erofs/zmap.c

+6 −14
Original line number Diff line number Diff line
@@ -272,21 +272,20 @@ static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m, 
		unsigned long lcn = m->lcn - lookback_distance;

		int err;



		if (!lookback_distance)

			break;



		err = z_erofs_load_lcluster_from_disk(m, lcn, false);

		if (err)

			return err;



		if (m->type == Z_EROFS_LCLUSTER_TYPE_NONHEAD) {

			lookback_distance = m->delta[0];

			if (!lookback_distance)

				break;

			continue;

		} else {

		}

		m->headtype = m->type;

		m->map->m_la = (lcn << lclusterbits) | m->clusterofs;

		return 0;

	}

	}

	erofs_err(sb, "bogus lookback distance %u @ lcn %lu of nid %llu",

		  lookback_distance, m->lcn, vi->nid);

	DBG_BUGON(1);
@@ -435,13 +434,6 @@ static int z_erofs_map_blocks_fo(struct inode *inode, 
			end = inode->i_size;

	} else {

		if (m.type != Z_EROFS_LCLUSTER_TYPE_NONHEAD) {

			/* m.lcn should be >= 1 if endoff < m.clusterofs */

			if (!m.lcn) {

				erofs_err(sb, "invalid logical cluster 0 at nid %llu",

					  vi->nid);

				err = -EFSCORRUPTED;

				goto unmap_out;

			}

			end = (m.lcn << lclusterbits) | m.clusterofs;

			map->m_flags |= EROFS_MAP_FULL_MAPPED;

			m.delta[0] = 1;