diff options
| -rw-r--r-- | drivers/md/raid10.c | 64 | ||||
| -rw-r--r-- | include/linux/raid/raid10.h | 7 |
2 files changed, 49 insertions, 22 deletions
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 2ca18770575..4db34edfd87 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -29,6 +29,7 @@ * raid_disks * near_copies (stored in low byte of layout) * far_copies (stored in second byte of layout) + * far_offset (stored in bit 16 of layout ) * * The data to be stored is divided into chunks using chunksize. * Each device is divided into far_copies sections. @@ -36,10 +37,14 @@ * near_copies copies of each chunk is stored (each on a different drive). * The starting device for each section is offset near_copies from the starting * device of the previous section. - * Thus there are (near_copies*far_copies) of each chunk, and each is on a different + * Thus they are (near_copies*far_copies) of each chunk, and each is on a different * drive. * near_copies and far_copies must be at least one, and their product is at most * raid_disks. + * + * If far_offset is true, then the far_copies are handled a bit differently. + * The copies are still in different stripes, but instead of be very far apart + * on disk, there are adjacent stripes. */ /* @@ -357,8 +362,7 @@ static int raid10_end_write_request(struct bio *bio, unsigned int bytes_done, in * With this layout, and block is never stored twice on the one device. * * raid10_find_phys finds the sector offset of a given virtual sector - * on each device that it is on. If a block isn't on a device, - * that entry in the array is set to MaxSector. + * on each device that it is on. * * raid10_find_virt does the reverse mapping, from a device and a * sector offset to a virtual address @@ -381,6 +385,8 @@ static void raid10_find_phys(conf_t *conf, r10bio_t *r10bio) chunk *= conf->near_copies; stripe = chunk; dev = sector_div(stripe, conf->raid_disks); + if (conf->far_offset) + stripe *= conf->far_copies; sector += stripe << conf->chunk_shift; @@ -414,16 +420,24 @@ static sector_t raid10_find_virt(conf_t *conf, sector_t sector, int dev) { sector_t offset, chunk, vchunk; - while (sector > conf->stride) { - sector -= conf->stride; - if (dev < conf->near_copies) - dev += conf->raid_disks - conf->near_copies; - else - dev -= conf->near_copies; - } - offset = sector & conf->chunk_mask; - chunk = sector >> conf->chunk_shift; + if (conf->far_offset) { + int fc; + chunk = sector >> conf->chunk_shift; + fc = sector_div(chunk, conf->far_copies); + dev -= fc * conf->near_copies; + if (dev < 0) + dev += conf->raid_disks; + } else { + while (sector > conf->stride) { + sector -= conf->stride; + if (dev < conf->near_copies) + dev += conf->raid_disks - conf->near_copies; + else + dev -= conf->near_copies; + } + chunk = sector >> conf->chunk_shift; + } vchunk = chunk * conf->raid_disks + dev; sector_div(vchunk, conf->near_copies); return (vchunk << conf->chunk_shift) + offset; @@ -900,9 +914,12 @@ static void status(struct seq_file *seq, mddev_t *mddev) seq_printf(seq, " %dK chunks", mddev->chunk_size/1024); if (conf->near_copies > 1) seq_printf(seq, " %d near-copies", conf->near_copies); - if (conf->far_copies > 1) - seq_printf(seq, " %d far-copies", conf->far_copies); - + if (conf->far_copies > 1) { + if (conf->far_offset) + seq_printf(seq, " %d offset-copies", conf->far_copies); + else + seq_printf(seq, " %d far-copies", conf->far_copies); + } seq_printf(seq, " [%d/%d] [", conf->raid_disks, conf->working_disks); for (i = 0; i < conf->raid_disks; i++) @@ -1915,7 +1932,7 @@ static int run(mddev_t *mddev) mirror_info_t *disk; mdk_rdev_t *rdev; struct list_head *tmp; - int nc, fc; + int nc, fc, fo; sector_t stride, size; if (mddev->chunk_size == 0) { @@ -1925,8 +1942,9 @@ static int run(mddev_t *mddev) nc = mddev->layout & 255; fc = (mddev->layout >> 8) & 255; + fo = mddev->layout & (1<<16); if ((nc*fc) <2 || (nc*fc) > mddev->raid_disks || - (mddev->layout >> 16)) { + (mddev->layout >> 17)) { printk(KERN_ERR "raid10: %s: unsupported raid10 layout: 0x%8x\n", mdname(mddev), mddev->layout); goto out; @@ -1958,12 +1976,16 @@ static int run(mddev_t *mddev) conf->near_copies = nc; conf->far_copies = fc; conf->copies = nc*fc; + conf->far_offset = fo; conf->chunk_mask = (sector_t)(mddev->chunk_size>>9)-1; conf->chunk_shift = ffz(~mddev->chunk_size) - 9; - stride = mddev->size >> (conf->chunk_shift-1); - sector_div(stride, fc); - conf->stride = stride << conf->chunk_shift; - + if (fo) + conf->stride = 1 << conf->chunk_shift; + else { + stride = mddev->size >> (conf->chunk_shift-1); + sector_div(stride, fc); + conf->stride = stride << conf->chunk_shift; + } conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc, r10bio_pool_free, conf); if (!conf->r10bio_pool) { diff --git a/include/linux/raid/raid10.h b/include/linux/raid/raid10.h index b1103298a8c..c41e56a7c09 100644 --- a/include/linux/raid/raid10.h +++ b/include/linux/raid/raid10.h @@ -24,11 +24,16 @@ struct r10_private_data_s { int far_copies; /* number of copies layed out * at large strides across drives */ + int far_offset; /* far_copies are offset by 1 stripe + * instead of many + */ int copies; /* near_copies * far_copies. * must be <= raid_disks */ sector_t stride; /* distance between far copies. - * This is size / far_copies + * This is size / far_copies unless + * far_offset, in which case it is + * 1 stripe. */ int chunk_shift; /* shift from chunks to sectors */ |