[linux-lvm] using LVM on top of mingo raid

[Daniel Mehrmann]

----- Original Message -----
From: "Andreas Dilger" <adilger at turbolabs.com>
To: "Linux LVM mailing list" <linux-lvm at msede.com>
Cc: <linux-raid at vger.rutgers.edu>
Sent: Tuesday, June 27, 2000 10:02 PM
Subject: [linux-lvm] using LVM on top of mingo raid


> Hello,
> I'm trying to get LVM 0.8 on top of Ingo's 0.9 RAID patches with
2.2.16
> (this appears to be the same issue as applying LVM on top of a RedHat
> kernel, which came up on the LVM list a few times, but was never
answered).
>
> There is a problem with applying the LVM patch to ll_rw_block.c, which
> I think I have fixed, but I'm not very certain of the RAID code, so
I'd
> like some comments on these changes:
>
> 2.2.16+LVM looks like :::: drivers/block/ll_rw_blk.c ::::::::::
>
========================================================================
====
> #ifdef CONFIG_BLK_DEV_MD
>                 if (major==MD_MAJOR &&
>                     /* changed             v   to allow LVM to remap
*/
>                     md_map (MINOR(bh[i]->b_rdev), &bh[i]->b_rdev,
>                             &bh[i]->b_rsector, bh[i]->b_size >> 9)) {
>                         printk (KERN_ERR
>                                 "Bad md_map in ll_rw_block\n");
>                         goto sorry;
>                 }
> #endif
>  [[[[snip]]]]
> /* changed         v  to allow LVM to remap */
>                         if (MAJOR(bh[i]->b_rdev) == MD_MAJOR) {
>                                 /* changed for LVM to remap     v */
>                                 md_make_request(MINOR (bh[i]->b_rdev),
rw, bh[i]);
>                                 continue;
>                         }
>
========================================================================
====
> 2.2.16+RAID0.9+LVM looks like this :::: drivers/block/ll_rw_blk.c
::::::::::
>
========================================================================
====
> #ifdef CONFIG_BLK_DEV_MD
>                 if (major==MD_MAJOR &&
> -                   md_map (bh[i]->b_dev, &bh[i]->b_rdev,
> +                   /* changed       v   to allow LVM to remap */
> +                   md_map (bh[i]->b_rdev, &bh[i]->b_rdev,
>                             &bh[i]->b_rsector, bh[i]->b_size >> 9)) {
>                         printk (KERN_ERR
>                                 "Bad md_map in ll_rw_block\n");
>                         goto sorry;
>                 }
> #endif
>  [[[[snip]]]]
> -                        if (MAJOR(bh[i]->b_dev) == MD_MAJOR) {
> +                        /* changed         v  to allow LVM to remap
*/
> +                        if (MAJOR(bh[i]->b_rdev) == MD_MAJOR) {
>                                 md_make_request(bh[i], rw);
>                                 continue;
>                         }
>
>  :::::::: in drivers/block/md.c ::::::::::
> static int md_make_request()
> {
> - mddev_t *mddev = kdev_to_mddev(bh->b_dev);
> +       /* changed                           v to allow LVM to remap
*/
> + mddev_t *mddev = kdev_to_mddev(bh->b_rdev);
>
========================================================================
====
>
> The md_make_request() uses the same mddev (i.e. uses b_rdev instead of
b_dev)
> in 2.4-test1, so I think this is correct.  I'm not certain of md_map()
> because it no longer exists in 2.4.  The change looks like it would
work
> (going from old to new RAID), but I have no idea as I've never set up
RAID
> before so there could be any number of problems...
>
> Cheers, Andreas
>
> PS - I'm not on the linux-raid list, so please CC any replies to me or
>      linux-lvm at msede.com
> --
> Andreas Dilger  \ "If a man ate a pound of pasta and a pound of
antipasto,
>                  \  would they cancel out, leaving him still hungry?"
> http://www-mddsp.enel.ucalgary.ca/People/adilger/               --
Dogbert
>


Dou you used may 2.2.16 LVM patch ?? If that is true i must correct it
:-\

--

Regards
Daniel

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