From: Gao Xiang hsiangkao@linux.alibaba.com
[ Upstream commit 9b32b063be1001e322c5f6e01f2a649636947851 ]
Sometimes, the on-disk metadata might be invalid due to user interrupts, storage failures, or other unknown causes.
In that case, z_erofs_map_blocks_iter() may still return a valid m_llen while other fields remain invalid (e.g., m_plen can be 0).
Due to the return value of z_erofs_scan_folio() in some path will be ignored on purpose, the following z_erofs_scan_folio() could then use the invalid value by accident.
Let's reset m_llen to 0 to prevent this.
Link: https://lore.kernel.org/r/20240629185743.2819229-1-hsiangkao@linux.alibaba.c... Signed-off-by: Gao Xiang hsiangkao@linux.alibaba.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/erofs/zmap.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c index abcded1acd194..4864863cd1298 100644 --- a/fs/erofs/zmap.c +++ b/fs/erofs/zmap.c @@ -763,6 +763,8 @@ int z_erofs_map_blocks_iter(struct inode *inode, struct erofs_map_blocks *map,
err = z_erofs_do_map_blocks(inode, map, flags); out: + if (err) + map->m_llen = 0; trace_z_erofs_map_blocks_iter_exit(inode, map, flags, err);
/* aggressively BUG_ON iff CONFIG_EROFS_FS_DEBUG is on */