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md/raid5: prepare for allowing reshape to change chunksize. 

Add "prev_chunk" to raid5_conf_t, similar to "previous_raid_disks", to
remember what the chunk size was before the reshape that is currently
underway.

This seems like duplication with "chunk_size" and "new_chunk" in
mddev_t, and to some extent it is, but there are differences.
The values in mddev_t are always defined and often the same.
The prev* values are only defined if a reshape is underway.

Also (and more significantly) the raid5_conf_t values will be changed
at the same time (inside an appropriate lock) that the reshape is
started by setting reshape_position.  In contrast, the new_chunk value
is set when the sysfs file is written which could be well before the
reshape starts.

Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2009-03-31 15:19:07 +11:00
parent 86b42c713b
commit 784052ecc6
2 changed files with 28 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
drivers/md/raid5.c
View File

@ -299,7 +299,7 @@ static int grow_buffers(struct stripe_head *sh, int num)
return 0;
}
static void raid5_build_block(struct stripe_head *sh, int i);
static void raid5_build_block(struct stripe_head *sh, int i, int previous);
static void stripe_set_idx(sector_t stripe, raid5_conf_t *conf, int previous,
struct stripe_head *sh);
@ -337,7 +337,7 @@ static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
BUG();
}
dev->flags = 0;
raid5_build_block(sh, i);
raid5_build_block(sh, i, previous);
}
insert_hash(conf, sh);
}
@ -1212,9 +1212,9 @@ static void raid5_end_write_request(struct bio *bi, int error)
}
static sector_t compute_blocknr(struct stripe_head *sh, int i);
static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous);
static void raid5_build_block(struct stripe_head *sh, int i)
static void raid5_build_block(struct stripe_head *sh, int i, int previous)
{
struct r5dev *dev = &sh->dev[i];
@ -1230,7 +1230,7 @@ static void raid5_build_block(struct stripe_head *sh, int i)
dev->req.bi_private = sh;
dev->flags = 0;
dev->sector = compute_blocknr(sh, i);
dev->sector = compute_blocknr(sh, i, previous);
}
static void error(mddev_t *mddev, mdk_rdev_t *rdev)
@ -1273,7 +1273,8 @@ static sector_t raid5_compute_sector(raid5_conf_t *conf, sector_t r_sector,
int pd_idx, qd_idx;
int ddf_layout = 0;
sector_t new_sector;
int sectors_per_chunk = conf->chunk_size >> 9;
int sectors_per_chunk = previous ? (conf->prev_chunk >> 9)
: (conf->chunk_size >> 9);
int raid_disks = previous ? conf->previous_raid_disks
: conf->raid_disks;
int data_disks = raid_disks - conf->max_degraded;
@ -1472,13 +1473,14 @@ static sector_t raid5_compute_sector(raid5_conf_t *conf, sector_t r_sector,
}
static sector_t compute_blocknr(struct stripe_head *sh, int i)
static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous)
{
raid5_conf_t *conf = sh->raid_conf;
int raid_disks = sh->disks;
int data_disks = raid_disks - conf->max_degraded;
sector_t new_sector = sh->sector, check;
int sectors_per_chunk = conf->chunk_size >> 9;
int sectors_per_chunk = previous ? (conf->prev_chunk >> 9)
: (conf->chunk_size >> 9);
sector_t stripe;
int chunk_offset;
int chunk_number, dummy1, dd_idx = i;
@ -1579,8 +1581,7 @@ static sector_t compute_blocknr(struct stripe_head *sh, int i)
r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset;
check = raid5_compute_sector(conf, r_sector,
(raid_disks != conf->raid_disks),
&dummy1, &sh2);
previous, &dummy1, &sh2);
if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
|| sh2.qd_idx != sh->qd_idx) {
printk(KERN_ERR "compute_blocknr: map not correct\n");
@ -1992,7 +1993,9 @@ static int page_is_zero(struct page *p)
static void stripe_set_idx(sector_t stripe, raid5_conf_t *conf, int previous,
struct stripe_head *sh)
{
int sectors_per_chunk = conf->chunk_size >> 9;
int sectors_per_chunk =
previous ? (conf->prev_chunk >> 9)
: (conf->chunk_size >> 9);
int dd_idx;
int chunk_offset = sector_div(stripe, sectors_per_chunk);
int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
@ -2662,7 +2665,7 @@ static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh,
int dd_idx, j;
struct stripe_head *sh2;
sector_t bn = compute_blocknr(sh, i);
sector_t bn = compute_blocknr(sh, i, 1);
sector_t s = raid5_compute_sector(conf, bn, 0,
&dd_idx, NULL);
sh2 = get_active_stripe(conf, s, 0, 1);
@ -3318,6 +3321,8 @@ static int raid5_mergeable_bvec(struct request_queue *q,
if ((bvm->bi_rw & 1) == WRITE)
return biovec->bv_len; /* always allow writes to be mergeable */
if (mddev->new_chunk < mddev->chunk_size)
chunk_sectors = mddev->new_chunk >> 9;
max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
if (max < 0) max = 0;
if (max <= biovec->bv_len && bio_sectors == 0)
@ -3333,6 +3338,8 @@ static int in_chunk_boundary(mddev_t *mddev, struct bio *bio)
unsigned int chunk_sectors = mddev->chunk_size >> 9;
unsigned int bio_sectors = bio->bi_size >> 9;
if (mddev->new_chunk < mddev->chunk_size)
chunk_sectors = mddev->new_chunk >> 9;
return chunk_sectors >=
((sector & (chunk_sectors - 1)) + bio_sectors);
}
@ -3788,7 +3795,7 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped
BUG_ON(conf->reshape_progress == 0);
stripe_addr = writepos;
BUG_ON((mddev->dev_sectors &
~((sector_t)mddev->chunk_size / 512 - 1))
~((sector_t)conf->chunk_size / 512 - 1))
- (conf->chunk_size / 512) - stripe_addr
!= sector_nr);
} else {
@ -3811,7 +3818,7 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped
if (conf->level == 6 &&
j == sh->qd_idx)
continue;
s = compute_blocknr(sh, j);
s = compute_blocknr(sh, j, 0);
if (s < raid5_size(mddev, 0, 0)) {
skipped = 1;
continue;
@ -4217,6 +4224,7 @@ raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks)
}
sectors &= ~((sector_t)mddev->chunk_size/512 - 1);
sectors &= ~((sector_t)mddev->new_chunk/512 - 1);
return sectors * (raid_disks - conf->max_degraded);
}
@ -4322,6 +4330,8 @@ static raid5_conf_t *setup_conf(mddev_t *mddev)
conf->algorithm = mddev->new_layout;
conf->max_nr_stripes = NR_STRIPES;
conf->reshape_progress = mddev->reshape_position;
if (conf->reshape_progress != MaxSector)
conf->prev_chunk = mddev->chunk_size;
memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
@ -4385,7 +4395,7 @@ static int run(mddev_t *mddev)
* geometry.
*/
here_new = mddev->reshape_position;
if (sector_div(here_new, (mddev->chunk_size>>9)*
if (sector_div(here_new, (mddev->new_chunk>>9)*
(mddev->raid_disks - max_degraded))) {
printk(KERN_ERR "raid5: reshape_position not "
"on a stripe boundary\n");
@ -4789,7 +4799,8 @@ static int raid5_check_reshape(mddev_t *mddev)
if ((mddev->chunk_size / STRIPE_SIZE) * 4 > conf->max_nr_stripes ||
(mddev->new_chunk / STRIPE_SIZE) * 4 > conf->max_nr_stripes) {
printk(KERN_WARNING "raid5: reshape: not enough stripes. Needed %lu\n",
(mddev->chunk_size / STRIPE_SIZE)*4);
(max(mddev->chunk_size, mddev->new_chunk)
/ STRIPE_SIZE)*4);
return -ENOSPC;
}

1
drivers/md/raid5.h
View File

@ -350,6 +350,7 @@ struct raid5_private_data {
*/
sector_t reshape_safe;
int previous_raid_disks;
int prev_chunk;
short generation; /* increments with every reshape */
struct list_head handle_list; /* stripes needing handling */