f2fs: fix to return correct error number in f2fs_sync_node_pages()

If __write_node_folio() failed, it will return AOP_WRITEPAGE_ACTIVATE,
the incorrect return value may be passed to userspace in below path,
fix it.

- sync_filesystem
 - sync_fs
  - f2fs_issue_checkpoint
   - block_operations
    - f2fs_sync_node_pages
     - __write_node_folio
     : return AOP_WRITEPAGE_ACTIVATE

Cc: [email protected]
Reported-by: Christoph Hellwig <[email protected]>
Signed-off-by: Chao Yu <[email protected]>
Signed-off-by: Jaegeuk Kim <[email protected]>

Author: chaseyu

fs/f2fs/node.c

@@ -2092,10 +2092,14 @@ int f2fs_sync_node_pages(struct f2fs_sb_info *sbi,
 
 			ret = __write_node_folio(folio, false, &submitted,
 						wbc, do_balance, io_type, NULL);
-			if (ret)
+			if (ret) {
 				folio_unlock(folio);
-			else if (submitted)
+				folio_batch_release(&fbatch);
+				ret = -EIO;
+				goto out;
+			} else if (submitted) {
 				nwritten++;
+			}
 
 			if (--wbc->nr_to_write == 0)
 				break;