From be45319c9fb1d5c272da9fd34854a7d39e7f58d1 Mon Sep 17 00:00:00 2001 From: Gao Xiang Date: Tue, 8 Apr 2025 19:44:48 +0800 Subject: [PATCH] erofs: fix encoded extents handling - The MSB 32 bits of `z_fragmentoff` are available only in extent records of size >= 8B. - Use round_down() to calculate `lstart` as well as increase `pos` correspondingly for extent records of size == 8B. Fixes: 1d191b4ca51d ("erofs: implement encoded extent metadata") Signed-off-by: Gao Xiang Link: https://lore.kernel.org/r/20250408114448.4040220-2-hsiangkao@linux.alibaba.com --- fs/erofs/zmap.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c index 8de50df05dfe..14ea47f954f5 100644 --- a/fs/erofs/zmap.c +++ b/fs/erofs/zmap.c @@ -559,7 +559,8 @@ static int z_erofs_map_blocks_ext(struct inode *inode, pos += sizeof(__le64); lstart = 0; } else { - lstart = map->m_la >> vi->z_lclusterbits; + lstart = round_down(map->m_la, 1 << vi->z_lclusterbits); + pos += (lstart >> vi->z_lclusterbits) * recsz; pa = EROFS_NULL_ADDR; } @@ -614,7 +615,7 @@ static int z_erofs_map_blocks_ext(struct inode *inode, if (last && (vi->z_advise & Z_EROFS_ADVISE_FRAGMENT_PCLUSTER)) { map->m_flags |= EROFS_MAP_MAPPED | EROFS_MAP_FRAGMENT; vi->z_fragmentoff = map->m_plen; - if (recsz >= offsetof(struct z_erofs_extent, pstart_lo)) + if (recsz > offsetof(struct z_erofs_extent, pstart_lo)) vi->z_fragmentoff |= map->m_pa << 32; } else if (map->m_plen) { map->m_flags |= EROFS_MAP_MAPPED |