From 61e144f65cc58286f65e693a06529b984126d670 Mon Sep 17 00:00:00 2001 From: Gao Xiang Date: Thu, 6 Feb 2025 20:50:34 +0800 Subject: [PATCH] erofs-utils: lib: clean up z_erofs_extent_lookback Source kernel commit: ab474fccd04509db89fde8d3b28c39aa9a47db64 Signed-off-by: Gao Xiang Link: https://lore.kernel.org/r/20250206125034.1462966-9-hsiangkao@linux.alibaba.com --- lib/zmap.c | 60 ++++++++++++++++++++++++------------------------------ 1 file changed, 27 insertions(+), 33 deletions(-) diff --git a/lib/zmap.c b/lib/zmap.c index e61efe3..b84d214 100644 --- a/lib/zmap.c +++ b/lib/zmap.c @@ -272,46 +272,40 @@ static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m, unsigned int lookback_distance) { struct erofs_inode *const vi = m->inode; - struct erofs_map_blocks *const map = m->map; const unsigned int lclusterbits = vi->z_logical_clusterbits; - unsigned long lcn = m->lcn; - int err; - if (lcn < lookback_distance) { - erofs_err("bogus lookback distance @ nid %llu", - (unsigned long long)vi->nid); - DBG_BUGON(1); - return -EFSCORRUPTED; - } + while (m->lcn >= lookback_distance) { + unsigned long lcn = m->lcn - lookback_distance; + int err; - /* load extent head logical cluster if needed */ - lcn -= lookback_distance; - err = z_erofs_load_lcluster_from_disk(m, lcn, false); - if (err) - return err; + err = z_erofs_load_lcluster_from_disk(m, lcn, false); + if (err) + return err; - switch (m->type) { - case Z_EROFS_LCLUSTER_TYPE_NONHEAD: - if (!m->delta[0]) { - erofs_err("invalid lookback distance 0 @ nid %llu", - (unsigned long long)vi->nid); + switch (m->type) { + case Z_EROFS_LCLUSTER_TYPE_NONHEAD: + lookback_distance = m->delta[0]; + if (!lookback_distance) + goto err_bogus; + continue; + case Z_EROFS_LCLUSTER_TYPE_PLAIN: + case Z_EROFS_LCLUSTER_TYPE_HEAD1: + case Z_EROFS_LCLUSTER_TYPE_HEAD2: + m->headtype = m->type; + m->map->m_la = (lcn << lclusterbits) | m->clusterofs; + return 0; + default: + erofs_err("unknown type %u @ lcn %lu of nid %llu", + m->type, lcn, vi->nid | 0ULL); DBG_BUGON(1); - return -EFSCORRUPTED; + return -EOPNOTSUPP; } - return z_erofs_extent_lookback(m, m->delta[0]); - case Z_EROFS_LCLUSTER_TYPE_PLAIN: - case Z_EROFS_LCLUSTER_TYPE_HEAD1: - case Z_EROFS_LCLUSTER_TYPE_HEAD2: - m->headtype = m->type; - map->m_la = (lcn << lclusterbits) | m->clusterofs; - break; - default: - erofs_err("unknown type %u @ lcn %lu of nid %llu", - m->type, lcn, (unsigned long long)vi->nid); - DBG_BUGON(1); - return -EOPNOTSUPP; } - return 0; +err_bogus: + erofs_err("bogus lookback distance %u @ lcn %lu of nid %llu", + lookback_distance, m->lcn | 0ULL, vi->nid); + DBG_BUGON(1); + return -EFSCORRUPTED; } static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m, -- 2.34.1