Re: [PATCH 1/5] btrfs: add ioctl BTRFS_IOC_DEV_PROPERTIES.

[Goffredo Baroncelli <kreijack@libero.it>]

On 2/10/21 5:08 PM, Josef Bacik wrote:
> On 2/1/21 4:28 PM, Goffredo Baroncelli wrote:
>> From: Goffredo Baroncelli <kreijack@inwind.it>
>>
>> This ioctl is a base for returning / setting information from / to  the
>> fields of the btrfs_dev_item object.
>>
>> For now only the "type" field is returned / set.
>>
>> Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it>
[...]
>> +    /* it is possible to set only BTRFS_DEV_PROPERTY_TYPE for now */
>> +    if (dev_props.properties & ~(BTRFS_DEV_PROPERTY_TYPE))
>> +        return -EPERM;
>> +
>> +    trans = btrfs_start_transaction(root, 0);
> 
> This needs to be 1, we're updating an item.

Ok

[...]
>> + * Up to 2020/05/11 the only properties that can be read/write is the 'type'
>> + * one.
>> + */
>> +struct btrfs_ioctl_dev_properties {
>> +    __u64    devid;
>> +    __u64    properties;
>> +    __u64    type;
>> +    __u32    dev_group;
>> +    __u8    seek_speed;
>> +    __u8    bandwidth;
>> +
>> +    /*
>> +     * for future expansion
>> +     */
>> +    __u8    unused1[2];
>> +    __u64    unused2[4];
>> +};
>> +
> 
> I think we're padding out to 1k for new stuff like this?  We can never have too much room for expansion.  Thanks,
Ok, in the next iteration this will be expanded up to 1kB

> 
> Josef

Ciao
Goffredo

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