Re: [PATCH 08/11] btrfs-progs: track total_devs in fs devices

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

On 14/07/2023 02:58, David Sterba wrote:
> On Fri, Jul 07, 2023 at 11:52:38PM +0800, Anand Jain wrote:
>> Similar to the kernel, introduce the btrfs_fs_devices::total_devs
>> attribute to know the overall count of devices that are expected
>> to be present per filesystem.
>>
>> Signed-off-by: Anand Jain <anand.jain@oracle.com>
>> ---
>>   kernel-shared/volumes.c | 4 +++-
>>   kernel-shared/volumes.h | 1 +
>>   2 files changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/kernel-shared/volumes.c b/kernel-shared/volumes.c
>> index 1e42e4fe105e..fd5890d033c8 100644
>> --- a/kernel-shared/volumes.c
>> +++ b/kernel-shared/volumes.c
>> @@ -367,7 +367,8 @@ static int device_list_add(const char *path,
>>   			       BTRFS_FSID_SIZE);
>>   
>>   		fs_devices->latest_devid = devid;
>> -		fs_devices->latest_trans = found_transid;
>> +		/* Below we would set this to found_transid */
>> +		fs_devices->latest_trans = 0;
>>   		fs_devices->lowest_devid = (u64)-1;
>>   		fs_devices->chunk_alloc_policy = BTRFS_CHUNK_ALLOC_REGULAR;
>>   		device = NULL;
>> @@ -438,6 +439,7 @@ static int device_list_add(const char *path,
>>   	if (found_transid > fs_devices->latest_trans) {
>>   		fs_devices->latest_devid = devid;
>>   		fs_devices->latest_trans = found_transid;
>> +		fs_devices->total_devices = device->total_devs;
>>   	}
>>   	if (fs_devices->lowest_devid > devid) {
>>   		fs_devices->lowest_devid = devid;
>> diff --git a/kernel-shared/volumes.h b/kernel-shared/volumes.h
>> index 93e02a901d31..09964f96ca37 100644
>> --- a/kernel-shared/volumes.h
>> +++ b/kernel-shared/volumes.h
>> @@ -90,6 +90,7 @@ struct btrfs_fs_devices {
>>   
>>   	u64 total_rw_bytes;
>>   
>> +	int total_devices;
>>   	int num_devices;
>>   	int missing;
> 
> All the device counters could be added separately, that's for the
> kernel/userspace parity.

Hm. I didn't get this. Could you please elaborate on this?

Thanks.

> 
>>   	int latest_bdev;
>> -- 
>> 2.39.3