[PATCH] erofs: fix compacted_{4b_initial, 2b} when compacted_4b_initial > totalidx

[Yue Hu]

From: Yue Hu <huyue2 at yulong.com>

mkfs.erofs will treat compacted_4b_initial & compacted_2b as 0 if
compacted_4b_initial > totalidx, kernel should be aligned with it
accordingly.

Signed-off-by: Yue Hu <huyue2 at yulong.com>
---
 fs/erofs/zmap.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 9fb98d8..4f941b6 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -369,7 +369,10 @@ static int compacted_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 	if (compacted_4b_initial == 32 / 4)
 		compacted_4b_initial = 0;
 
-	if (vi->z_advise & Z_EROFS_ADVISE_COMPACTED_2B)
+	if (compacted_4b_initial > totalidx) {
+		compacted_4b_initial = 0;
+		compacted_2b = 0;
+	} else if (vi->z_advise & Z_EROFS_ADVISE_COMPACTED_2B)
 		compacted_2b = rounddown(totalidx - compacted_4b_initial, 16);
 	else
 		compacted_2b = 0;
-- 
1.9.1