Re: [PATCH 5/8] btrfs: check if the fsid in the primary sb and copy sb are same

[Anand Jain <anand.jain@oracle.com>]

>>>> +    for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
>>>> +        u64 bytenr = btrfs_sb_offset(i);
>>>> +
>>>> +        ret = btrfs_read_disk_super(bdev, bytenr, &page, &disk_super);
>>>> +        if (ret) {
>>>> +            if (i == 0)
>>>> +                goto error_kfree;
>>>> +            /* copy2 is optional */
>>>> +            ret = 0;
>>>> +            continue;
>>>> +        }
>>>> +
>>>> +        if (i == 0) {
>>>> +            memcpy(disk_super_primary, disk_super,
>>>> +                   sizeof(*disk_super_primary));
>>>> +            btrfs_release_disk_super(page);
>>>> +            continue;
>>>
>>> Doing the memcpy is enough here, the bottom of the loop already releases
>>> the disk page and continues on the next iteration.
>>
>>   The page map happens inside btrfs_read_disk_super(), we
>>   need unmap before going for the next superblock.
> 
> You already have  btrfs_release_disk_super(page); called at the end of
> the iteration, right after the closing bracket for the else, see below...

   Ah. You meant only memcpy. Yes.
   This part of the code is completely changed in V2. Thanks.