ntfs3: fix uninit memory after failed mi_read in mi_format_new

In the Linux kernel, the following vulnerability has been resolved: ntfs3: fix uninit memory after failed mi_read in mi_format_new Fix a KMSAN un-init bug found by syzkaller. ntfs_get_bh() expects a buffer from sb_getblk(), that buffer may not be uptodate. We do not bring the buffer uptodate before setting it as uptodate. If the buffer were to not be uptodate, it could mean adding a buffer with un-init data to the mi record. Attempting to load that record will trigger KMSAN. Avoid this by setting the buffer as uptodate, if it’s not already, by overwriting it.