On Thu, May 27, 2021 at 03:27:32PM +0900, Naohiro Aota wrote:

In btrfs_get_dev_zone_info(), we have "u32 sb_zone" and calculate "sector_t
sector" by shifting it. But, this "sector" is calculated in 32bit, leading
it to be 0 for the 2nd superblock copy.

Since zone number is u32, shifting it to sector (sector_t) or physical
address (u64) can easily trigger a missing cast bug like this.

This commit introduces helpers to convert zone number to sector/LBA, so we
won't fall into the same pitfall again.

Fixes: 12659251ca5d ("btrfs: implement log-structured superblock for ZONED mode")
Cc: stable@vger.kernel.org # 5.11+
Reported-by: Dmitry Fomichev <redacted>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>

Added to misc-next, thanks.