Sometimes, the on-disk metadata might be invalid due to storageuser interrupts, storage failures, or other unknown causes.
failure or other unknown issues.
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.
Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>
---
fs/erofs/zmap.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 9b248ee5fef2..74d3d7bffcf3 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -711,6 +711,8 @@ 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);
return err;
}