BugLink: https://bugs.launchpad.net/bugs/1818797

commit e1da7872 upstream.

This patch introduces verify_blkaddr to check meta/data block address
with valid range to detect bug earlier.

In addition, once we encounter an invalid blkaddr, notice user to run
fsck to fix, and let the kernel panic.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
[bwh: Backported to 4.4:
 - I skipped an earlier renaming of is_valid_meta_blkaddr() to
   f2fs_is_valid_meta_blkaddr()
 - Drop inapplicable change to check on f2fs_fio_info::old_blkaddr
 - Adjust context]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>