Messages in this thread Patch in this message | | | From | NeilBrown <> | Date | Tue, 14 Nov 2006 11:22:28 +1100 | Subject | [PATCH 001 of 4] md: Fix innocuous bug in raid6 stripe_to_pdidx |
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stripe_to_pdidx finds the index of the parity disk for a given stripe. It assumes raid5 in that it uses "disks-1" to determine the number of data disks.
This is incorrect for raid6 but fortunately the two usages cancel each other out. The only way that 'data_disks' affects the calculation of pd_idx in raid5_compute_sector is when it is divided into the sector number. But as that sector number is calculated by multiplying in the wrong value of 'data_disks' the division produces the right value.
So it is innocuous but needs to be fixed.
Signed-off-by: Neil Brown <neilb@suse.de>
### Diffstat output ./drivers/md/raid5.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c --- .prev/drivers/md/raid5.c 2006-11-14 10:05:00.000000000 +1100 +++ ./drivers/md/raid5.c 2006-11-14 10:33:41.000000000 +1100 @@ -1355,8 +1355,10 @@ static int stripe_to_pdidx(sector_t stri int pd_idx, dd_idx; int chunk_offset = sector_div(stripe, sectors_per_chunk); - raid5_compute_sector(stripe*(disks-1)*sectors_per_chunk - + chunk_offset, disks, disks-1, &dd_idx, &pd_idx, conf); + raid5_compute_sector(stripe * (disks - conf->max_degraded) + *sectors_per_chunk + chunk_offset, + disks, disks - conf->max_degraded, + &dd_idx, &pd_idx, conf); return pd_idx; } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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