On Fri, Dec 18 2009 at 2:30am -0500, Martin K. Petersen <martin.petersen@xxxxxxxxxx> wrote: > > The dm device limits function passes the start sector within the block > device to the block layer stacking function. However, the partition's > offset on the physical device is not added, resulting in incorrect > alignment reporting. > > Add the partition offset to the values passed to blk_stack_limits(). > > Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Martin, This is not required because DM assumes alignment_offset has already been accounted for by the caller (e.g. LVM2 or some other ficitional DM consumer). Below, "start" represents the aligned start of the data for a given volume. That start must have already been shifted by alignment_offset; as is the case with lvm2 (>= 2.02.51), see the following lvm2 commits: http://sources.redhat.com/git/gitweb.cgi?p=lvm2.git;a=commit;h=282029eb45e56 http://sources.redhat.com/git/gitweb.cgi?p=lvm2.git;a=commit;h=6c88b6c660020 All this being said, how did you arrive at this patch? Why do you feel it is needed? Was it just from code inspection? Regards, Mike > diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c > index be62547..67efac9 100644 > --- a/drivers/md/dm-table.c > +++ b/drivers/md/dm-table.c > @@ -495,6 +495,7 @@ int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev, > struct queue_limits *limits = data; > struct block_device *bdev = dev->bdev; > struct request_queue *q = bdev_get_queue(bdev); > + sector_t offset = (get_start_sect(bdev) + start) << 9; > char b[BDEVNAME_SIZE]; > > if (unlikely(!q)) { > @@ -503,7 +504,7 @@ int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev, > return 0; > } > > - if (blk_stack_limits(limits, &q->limits, start << 9) < 0) > + if (blk_stack_limits(limits, &q->limits, offset) < 0) > DMWARN("%s: target device %s is misaligned: " > "physical_block_size=%u, logical_block_size=%u, " > "alignment_offset=%u, start=%llu", > @@ -511,7 +512,7 @@ int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev, > q->limits.physical_block_size, > q->limits.logical_block_size, > q->limits.alignment_offset, > - (unsigned long long) start << 9); > + (unsigned long long) offset); > > > /* -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
