Re: [PATCH RESEND v2 1/2] btrfs: drop never met condition of disk_total_bytes == 0

[Josef Bacik <josef@toxicpanda.com>]

On 10/21/20 12:16 AM, Anand Jain wrote:
> btrfs_device::disk_total_bytes is set even for a seed device (the
> comment is wrong).
> 
> The function fill_device_from_item() does the job of reading it from the
> item and updating btrfs_device::disk_total_bytes. So both the missing
> device and the seed devices do have their disk_total_bytes updated.
> 
> Furthermore, while removing the device if there is a power loss, we could
> have a device with its total_bytes = 0, that's still valid.
> 
> So this patch removes the check dev->disk_total_bytes == 0 in the
> function verify_one_dev_extent(), which it does nothing in it.
> 
> And take this opportunity to introduce a check if the device::total_bytes
> is more than the max device size in read_one_dev().
> 
> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> Reviewed-by: Nikolay Borisov <nborisov@suse.com>
> ---
> v2: add check if the total_bytes is more than the actual device size in
>      read_one_dev().
>      update change log.
> 
>   fs/btrfs/volumes.c | 25 ++++++++++---------------
>   1 file changed, 10 insertions(+), 15 deletions(-)
> 
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 2a5397fb4175..0c6049f9ace3 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -6847,6 +6847,16 @@ static int read_one_dev(struct extent_buffer *leaf,
>   	}
>   
>   	fill_device_from_item(leaf, dev_item, device);
> +	if (device->bdev) {
> +		u64 max_total_bytes = i_size_read(device->bdev->bd_inode);
> +
> +		if (device->total_bytes > max_total_bytes) {
> +			btrfs_err(fs_info,
> +			"device total_bytes should be below %llu but found %llu",

"should be less than or equal to"

Thanks,

Josef