[pnfs] 答复: [PATCH] support multi-volume

[Sorin Faibish]

On Mon, 31 Aug 2009 21:42:22 -0400, Hongyuan Ma <mahongyuan at nrchpc.ac.cn>  
wrote:

> Hi, Fred
> I have not noticed this problem. I'll try to add 'vi_put_done' and test.
> BTW: Could you give me an example of two different devices point to the  
> same
> disk?
A FS initially built on a partition of a disk/volume and later extended on  
another
partition of the same disk/volume. Both use disk but on different  
partitions
and there are 2 different stripes on same volume. The server will create 2
different layouts with different offsets on same volume.

>
> ==============================================================
> Hongyuan Ma
> Tel: (86)10-6260-0522
> Mailing: P. O. Box 2704# Beijing
> Postcode: 100190
> National Research Centre for High Performance Computers
> Institute of Computing Technology, Chinese Academy of Sciences
> No. 6, South Kexueyuan Road, Haidian District
> Beijing, China
>
>
> -----Original Message-----
> From: faisaman4 at gmail.com [mailto:faisaman4 at gmail.com] On Behalf Of Fred
> Isaman
> Sent: Tuesday, September 01, 2009 12:10 AM
> To: Hongyuan Ma
> Cc: Benny Halevy; pnfs at linux-nfs.org
> Subject: Re: [pnfs] 答复: [PATCH] support multi-volume
>
> 2009/8/30 Hongyuan Ma <mahongyuan at nrchpc.ac.cn>:
>> Hi,
>> I fixed multi-volume bug which I found several days ago and send this  
>> bug
> to
>> the mail list.
>> The code which was cleaned up will only make the last device in sdlist
>> works, and the previous devices will be put in  
>> nfs4_blk_destroy_disk_list.
>> This is why dm can't find block_device, and cause NULL pointer which I
> have
>> posted the oops...
>>
>
> Your fix causes problems if two different devices point to the same disk.
> Does the following work for you?
>
> Fred
>
> diff --git a/fs/nfs/blocklayout/blocklayout.h
> b/fs/nfs/blocklayout/blocklayout.h
> index 0111ee2..37828ac 100644
> --- a/fs/nfs/blocklayout/blocklayout.h
> +++ b/fs/nfs/blocklayout/blocklayout.h
> @@ -68,6 +68,7 @@ struct visible_block_device {
>  	struct list_head	vi_node;
>  	struct block_device	*vi_bdev;
>  	int			vi_mapped;
> +	int			vi_put_done;
>  };
>
>  enum blk_vol_type {
> diff --git a/fs/nfs/blocklayout/blocklayoutdev.c
> b/fs/nfs/blocklayout/blocklayoutdev.c
> index 5d028ef..db75177 100644
> --- a/fs/nfs/blocklayout/blocklayoutdev.c
> +++ b/fs/nfs/blocklayout/blocklayoutdev.c
> @@ -91,6 +91,7 @@ static int alloc_add_disk(struct block_device
> *blk_dev, struct list_head *dlist)
>  	}
>  	vis_dev->vi_bdev = blk_dev;
>  	vis_dev->vi_mapped = 0;
> +	vis_dev->vi_put_done = 0;
>  	list_add(&vis_dev->vi_node, dlist);
>  	return 0;
>  }
> @@ -182,7 +183,7 @@ void nfs4_blk_destroy_disk_list(struct list_head  
> *dlist)
>  				MAJOR(vis_dev->vi_bdev->bd_dev),
>  				MINOR(vis_dev->vi_bdev->bd_dev));
>  		list_del(&vis_dev->vi_node);
> -		if (!vis_dev->vi_mapped)
> +		if (!vis_dev->vi_put_done)
>  			nfs4_blkdev_put(vis_dev->vi_bdev);
>  		kfree(vis_dev);
>  	}
> @@ -385,6 +386,7 @@ static int map_sig_to_device(struct pnfs_blk_sig  
> *sig,
>  			/* We no longer need to scan this device, and
>  			 * we need to "put" it before creating metadevice.
>  			 */
> +			vis_dev->vi_put_done = 1;
>  			nfs4_blkdev_put(vis_dev->vi_bdev);
>  			break;
>  		}
>
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-- 
Best Regards
Sorin Faibish
Corporate Distinguished Engineer
Network Storage Group

        EMC²
where information lives

Phone: 508-435-1000 x 48545
Cellphone: 617-510-0422
Email : sfaibish at emc.com