diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 559380a535af..4553be650968 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -888,15 +888,13 @@ static void z_erofs_do_decompressed_bvec(struct z_erofs_decompress_backend *be,
 
 	if (!((bvec->offset + be->pcl->pageofs_out) & ~PAGE_MASK)) {
 		unsigned int pgnr;
-		struct page *oldpage;
 
 		pgnr = (bvec->offset + be->pcl->pageofs_out) >> PAGE_SHIFT;
 		DBG_BUGON(pgnr >= be->nr_pages);
-		oldpage = be->decompressed_pages[pgnr];
-		be->decompressed_pages[pgnr] = bvec->page;
-
-		if (!oldpage)
+		if (!be->decompressed_pages[pgnr]) {
+			be->decompressed_pages[pgnr] = bvec->page;
 			return;
+		}
 	}
 
 	/* (cold path) one pcluster is requested multiple times */
diff --git a/fs/erofs/zdata.h b/fs/erofs/zdata.h
index e7f04c4fbb81..d98c95212985 100644
--- a/fs/erofs/zdata.h
+++ b/fs/erofs/zdata.h
@@ -126,10 +126,10 @@ static inline unsigned int z_erofs_pclusterpages(struct z_erofs_pcluster *pcl)
 }
 
 /*
- * bit 31: I/O error occurred on this page
- * bit 0 - 30: remaining parts to complete this page
+ * bit 30: I/O error occurred on this page
+ * bit 0 - 29: remaining parts to complete this page
  */
-#define Z_EROFS_PAGE_EIO			(1 << 31)
+#define Z_EROFS_PAGE_EIO			(1 << 30)
 
 static inline void z_erofs_onlinepage_init(struct page *page)
 {