Commit be45319c authored by Gao Xiang's avatar Gao Xiang
Browse files

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: 1d191b4c ("erofs: implement encoded extent metadata")
Signed-off-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250408114448.4040220-2-hsiangkao@linux.alibaba.com
parent d385f15d

fs/erofs/zmap.c

+3 −2
Original line number Diff line number Diff line
@@ -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 |