[PATCH v2] erofs: handle 48-bit blocks/uniaddr for extra devices

[Gao Xiang]

On 2026/4/3 14:36, Zhan Xusheng wrote:
> erofs_init_device() only reads blocks_lo and uniaddr_lo from the
> on-disk device slot, ignoring blocks_hi and uniaddr_hi that were
> introduced alongside the 48-bit block addressing feature.
> 
> For the primary device (dif0), erofs_read_superblock() already handles
> this correctly by combining blocks_lo with blocks_hi when 48-bit
> layout is enabled.  But the same logic was not applied to extra
> devices.
> 
> With a 48-bit EROFS image using extra devices whose uniaddr or blocks
> exceed 32-bit range, the truncated values cause erofs_map_dev() to
> compute wrong physical addresses, leading to silent data corruption.
> 
> Fix this by reading blocks_hi and uniaddr_hi in erofs_init_device()
> when 48-bit layout is enabled, consistent with the primary device
> handling.  Also fix the erofs_deviceslot on-disk definition where
> blocks_hi was incorrectly declared as __le32 instead of __le16.
> 
> Fixes: 61ba89b57905 ("erofs: add 48-bit block addressing on-disk support")
> Suggested-by: Gao Xiang <hsiangkao at linux.alibaba.com>
> Signed-off-by: Zhan Xusheng <zhanxusheng at xiaomi.com>

Thanks,

Reviewed-by: Gao Xiang <hsiangkao at linux.alibaba.com>

Thanks,
Gao Xiang