Messages in this thread | | | Date | Thu, 12 Oct 2006 00:01:21 -0400 | From | Phillip Susi <> | Subject | Re: dm stripe: Fix bounds |
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This patch broke my system. I am booting from a hardware fakeraid consisting of a raid-0 between two WD 36 gig 10,000 rpm raptors on a VIA sata raid controller. The dmraid utility previously would correctly configure dm to access the device ( though I did see some of the IO errors you mention in my logs ) and now dmraid fails to configure the dm table because this patch rejects it. My working dmraid table follows:
via_hfciifae: 0 144607678 striped 2 128 8:0 0 8:16 0
I believe the correct thing to do is to special case the last stripe in the volume like such:
0-31 64-67 32-63 68-71
Alasdair G Kergon wrote: > From: Kevin Corry <kevcorry@us.ibm.com> > > The dm-stripe target currently does not enforce that the size of a stripe > device be a multiple of the chunk-size. Under certain conditions, this can > lead to I/O requests going off the end of an underlying device. This > test-case shows one example. > > echo "0 100 linear /dev/hdb1 0" | dmsetup create linear0 > echo "0 100 linear /dev/hdb1 100" | dmsetup create linear1 > echo "0 200 striped 2 32 /dev/mapper/linear0 0 /dev/mapper/linear1 0" | \ > dmsetup create stripe0 > dd if=/dev/zero of=/dev/mapper/stripe0 bs=1k > > This will produce the output: > dd: writing '/dev/mapper/stripe0': Input/output error > 97+0 records in > 96+0 records out > > And in the kernel log will be: > attempt to access beyond end of device > dm-0: rw=0, want=104, limit=100 > > The patch below will check that the table size is a multiple of the stripe > chunk-size when the table is created, which will prevent the above striped > device from being created. > > This should not affect tools like LVM or EVMS, since in all the cases I can > think of, striped devices are always created with the sizes being a multiple > of the chunk-size. > > The size of a stripe device must be a multiple of its chunk-size. > > Signed-off-by: Kevin Corry <kevcorry@us.ibm.com> > Signed-Off-By: Alasdair G Kergon <agk@redhat.com> > > dm-stripe.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > Index: linux-2.6.16-rc5/drivers/md/dm-stripe.c > =================================================================== > --- linux-2.6.16-rc5.orig/drivers/md/dm-stripe.c 2006-03-14 18:25:38.000000000 +0000 > +++ linux-2.6.16-rc5/drivers/md/dm-stripe.c 2006-03-15 17:56:37.000000000 +0000 > @@ -103,9 +103,15 @@ static int stripe_ctr(struct dm_target * > return -EINVAL; > } > > + if (((uint32_t)ti->len) & (chunk_size - 1)) { > + ti->error = "dm-stripe: Target length not divisible by " > + "chunk size"; > + return -EINVAL; > + } > + > width = ti->len; > if (sector_div(width, stripes)) { > - ti->error = "dm-stripe: Target length not divisable by " > + ti->error = "dm-stripe: Target length not divisible by " > "number of stripes"; > return -EINVAL; > }
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