[PATCH 004 of 7] md: Core of raid5 resize process
From: NeilBrown
Date: Mon Jan 23 2006 - 19:40:53 EST
This patch provides the core of the resize/expand process.
sync_request notices if a 'reshape' is happening and acts accordingly.
It allocated new stripe_heads for the next chunk-wide-stripe in the
target geometry, marking them STRIPE_EXPANDING.
Then it finds which stripe heads in the old geometry can provide data
needed by these and marks them STRIPE_EXPAND_SOURCE. This causes
stripe_handle to read all blocks on those stripes.
Once all blocks on a STRIPE_EXPAND_SOURCE stripe_head are read, and that
are needed are copied into the corresponding STRIPE_EXPANDING stripe_head.
Once a STRIPE_EXPANDING stripe_head is full, it is marks STRIPE_EXPAND_READY
and then is written out and released.
Signed-off-by: Neil Brown <neilb@xxxxxxx>
### Diffstat output
./drivers/md/md.c | 10 +-
./drivers/md/raid5.c | 189 +++++++++++++++++++++++++++++++++++++------
./include/linux/raid/md_k.h | 4
./include/linux/raid/raid5.h | 4
4 files changed, 181 insertions(+), 26 deletions(-)
diff ./drivers/md/md.c~current~ ./drivers/md/md.c
--- ./drivers/md/md.c~current~ 2006-01-24 10:39:55.000000000 +1100
+++ ./drivers/md/md.c 2006-01-24 10:39:52.000000000 +1100
@@ -2151,7 +2151,9 @@ action_show(mddev_t *mddev, char *page)
char *type = "idle";
if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
test_bit(MD_RECOVERY_NEEDED, &mddev->recovery)) {
- if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
+ if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
+ type = "reshape";
+ else if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
type = "resync";
else if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
@@ -4067,8 +4069,10 @@ static void status_resync(struct seq_fil
seq_printf(seq, "] ");
}
seq_printf(seq, " %s =%3lu.%lu%% (%lu/%lu)",
+ (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)?
+ "reshape" :
(test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ?
- "resync" : "recovery"),
+ "resync" : "recovery")),
res/10, res % 10, resync, max_blocks);
/*
@@ -4656,6 +4660,8 @@ static void md_do_sync(mddev_t *mddev)
mddev->pers->sync_request(mddev, max_sectors, &skipped, 1);
if (!test_bit(MD_RECOVERY_ERR, &mddev->recovery) &&
+ test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
+ !test_bit(MD_RECOVERY_CHECK, &mddev->recovery) &&
mddev->curr_resync > 2 &&
mddev->curr_resync >= mddev->recovery_cp) {
if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
diff ./drivers/md/raid5.c~current~ ./drivers/md/raid5.c
--- ./drivers/md/raid5.c~current~ 2006-01-24 10:39:55.000000000 +1100
+++ ./drivers/md/raid5.c 2006-01-24 10:40:14.000000000 +1100
@@ -93,11 +93,13 @@ static void __release_stripe(raid5_conf_
if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
md_wakeup_thread(conf->mddev->thread);
}
- list_add_tail(&sh->lru, &conf->inactive_list);
atomic_dec(&conf->active_stripes);
- if (!conf->inactive_blocked ||
- atomic_read(&conf->active_stripes) < (conf->max_nr_stripes*3/4))
- wake_up(&conf->wait_for_stripe);
+ if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
+ list_add_tail(&sh->lru, &conf->inactive_list);
+ if (!conf->inactive_blocked ||
+ atomic_read(&conf->active_stripes) < (conf->max_nr_stripes*3/4))
+ wake_up(&conf->wait_for_stripe);
+ }
}
}
}
@@ -273,9 +275,8 @@ static struct stripe_head *get_active_st
} else {
if (!test_bit(STRIPE_HANDLE, &sh->state))
atomic_inc(&conf->active_stripes);
- if (list_empty(&sh->lru))
- BUG();
- list_del_init(&sh->lru);
+ if (!list_empty(&sh->lru))
+ list_del_init(&sh->lru);
}
}
} while (sh == NULL);
@@ -1021,6 +1022,18 @@ static int add_stripe_bio(struct stripe_
return 0;
}
+int stripe_to_pdidx(sector_t stripe, raid5_conf_t *conf, int disks)
+{
+ int sectors_per_chunk = conf->chunk_size >> 9;
+ sector_t x = stripe;
+ int pd_idx, dd_idx;
+ int chunk_offset = sector_div(x, sectors_per_chunk);
+ stripe = x;
+ raid5_compute_sector(stripe*(disks-1)*sectors_per_chunk
+ + chunk_offset, disks, disks-1, &dd_idx, &pd_idx, conf);
+ return pd_idx;
+}
+
/*
* handle_stripe - do things to a stripe.
@@ -1047,7 +1060,7 @@ static void handle_stripe(struct stripe_
struct bio *return_bi= NULL;
struct bio *bi;
int i;
- int syncing;
+ int syncing, expanding, expanded;
int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0;
int non_overwrite = 0;
int failed_num=0;
@@ -1062,6 +1075,8 @@ static void handle_stripe(struct stripe_
clear_bit(STRIPE_DELAYED, &sh->state);
syncing = test_bit(STRIPE_SYNCING, &sh->state);
+ expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
+ expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
/* Now to look around and see what can be done */
rcu_read_lock();
@@ -1254,13 +1269,14 @@ static void handle_stripe(struct stripe_
* parity, or to satisfy requests
* or to load a block that is being partially written.
*/
- if (to_read || non_overwrite || (syncing && (uptodate < disks))) {
+ if (to_read || non_overwrite || (syncing && (uptodate < disks)) || expanding) {
for (i=disks; i--;) {
dev = &sh->dev[i];
if (!test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&
(dev->toread ||
(dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
syncing ||
+ expanding ||
(failed && (sh->dev[failed_num].toread ||
(sh->dev[failed_num].towrite && !test_bit(R5_OVERWRITE, &sh->dev[failed_num].flags))))
)
@@ -1450,13 +1466,76 @@ static void handle_stripe(struct stripe_
set_bit(R5_Wantwrite, &dev->flags);
set_bit(R5_ReWrite, &dev->flags);
set_bit(R5_LOCKED, &dev->flags);
+ locked++;
} else {
/* let's read it back */
set_bit(R5_Wantread, &dev->flags);
set_bit(R5_LOCKED, &dev->flags);
+ locked++;
}
}
+ if (expanded && test_bit(STRIPE_EXPANDING, &sh->state)) {
+ /* Need to write out all blocks after computing parity */
+ sh->disks = conf->raid_disks;
+ sh->pd_idx = stripe_to_pdidx(sh->sector, conf, conf->raid_disks);
+ compute_parity(sh, RECONSTRUCT_WRITE);
+ for (i= conf->raid_disks; i--;) {
+ set_bit(R5_LOCKED, &sh->dev[i].flags);
+ locked++;
+ set_bit(R5_Wantwrite, &sh->dev[i].flags);
+ }
+ clear_bit(STRIPE_EXPANDING, &sh->state);
+ } else if (expanded) {
+ clear_bit(STRIPE_EXPAND_READY, &sh->state);
+ wake_up(&conf->wait_for_overlap);
+ md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
+ }
+
+ if (expanding && locked == 0) {
+ /* We have read all the blocks in this stripe and now we need to
+ * copy some of them into a target stripe for expand.
+ */
+ clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
+ for (i=0; i< sh->disks; i++)
+ if (i != sh->pd_idx) {
+ int dd_idx, pd_idx, j;
+ struct stripe_head *sh2;
+
+ sector_t bn = compute_blocknr(sh, i);
+ sector_t s = raid5_compute_sector(bn, conf->raid_disks,
+ conf->raid_disks-1,
+ &dd_idx, &pd_idx, conf);
+ sh2 = get_active_stripe(conf, s, conf->raid_disks, pd_idx, 1);
+ if (sh2 == NULL)
+ /* so far only the early blocks of this stripe
+ * have been requested. When later blocks
+ * get requested, we will try again
+ */
+ continue;
+ if(!test_bit(STRIPE_EXPANDING, &sh2->state) ||
+ test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
+ /* must have already done this block */
+ release_stripe(sh2);
+ continue;
+ }
+ memcpy(page_address(sh2->dev[dd_idx].page),
+ page_address(sh->dev[i].page),
+ STRIPE_SIZE);
+ set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
+ set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
+ for (j=0; j<conf->raid_disks; j++)
+ if (j != sh2->pd_idx &&
+ !test_bit(R5_Expanded, &sh2->dev[j].flags))
+ break;
+ if (j == conf->raid_disks) {
+ set_bit(STRIPE_EXPAND_READY, &sh2->state);
+ set_bit(STRIPE_HANDLE, &sh2->state);
+ }
+ release_stripe(sh2);
+ }
+ }
+
spin_unlock(&sh->lock);
while ((bi=return_bi)) {
@@ -1495,7 +1574,7 @@ static void handle_stripe(struct stripe_
rcu_read_unlock();
if (rdev) {
- if (syncing)
+ if (syncing || expanding || expanded)
md_sync_acct(rdev->bdev, STRIPE_SECTORS);
bi->bi_bdev = rdev->bdev;
@@ -1743,12 +1822,8 @@ static sector_t sync_request(mddev_t *md
{
raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
struct stripe_head *sh;
- int sectors_per_chunk = conf->chunk_size >> 9;
- sector_t x;
- unsigned long stripe;
- int chunk_offset;
- int dd_idx, pd_idx;
- sector_t first_sector;
+ int pd_idx;
+ sector_t first_sector, last_sector;
int raid_disks = conf->raid_disks;
int data_disks = raid_disks-1;
sector_t max_sector = mddev->size << 1;
@@ -1767,6 +1842,80 @@ static sector_t sync_request(mddev_t *md
return 0;
}
+
+ if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
+ /* reshaping is quite different to recovery/resync so it is
+ * handled quite separately ... here.
+ *
+ * On each call to sync_request, we gather one chunk worth of
+ * destination stripes and flag them as expanding.
+ * Then we find all the source stripes and request reads.
+ * As the reads complete, handle_stripe will copy the data
+ * into the destination stripe and release that stripe.
+ */
+ int i;
+ int dd_idx;
+ for (i=0; i < conf->chunk_size/512; i+= STRIPE_SECTORS) {
+ int j;
+ int skipped = 0;
+ pd_idx = stripe_to_pdidx(sector_nr+i, conf, conf->raid_disks);
+ sh = get_active_stripe(conf, sector_nr+i,
+ conf->raid_disks, pd_idx, 0);
+ set_bit(STRIPE_EXPANDING, &sh->state);
+ /* If any of this stripe is beyond the end of the old
+ * array, then we need to zero those blocks
+ */
+ for (j=sh->disks; j--;) {
+ sector_t s;
+ if (j == sh->pd_idx)
+ continue;
+ s = compute_blocknr(sh, j);
+ if (s < (mddev->array_size<<1)) {
+ skipped = 1;
+ continue;
+ }
+ memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);
+ set_bit(R5_Expanded, &sh->dev[j].flags);
+ set_bit(R5_UPTODATE, &sh->dev[j].flags);
+ }
+ if (!skipped) {
+ set_bit(STRIPE_EXPAND_READY, &sh->state);
+ set_bit(STRIPE_HANDLE, &sh->state);
+ }
+ release_stripe(sh);
+ }
+ spin_lock_irq(&conf->device_lock);
+ conf->expand_progress = (sector_nr + i)*(conf->raid_disks-1);
+ spin_unlock_irq(&conf->device_lock);
+ /* Ok, those stripe are ready. We can start scheduling
+ * reads on the source stripes.
+ * The source stripes are determined by mapping the first and last
+ * block on the destination stripes.
+ */
+ raid_disks = conf->previous_raid_disks;
+ data_disks = raid_disks - 1;
+ first_sector =
+ raid5_compute_sector(sector_nr*(conf->raid_disks-1),
+ raid_disks, data_disks,
+ &dd_idx, &pd_idx, conf);
+ last_sector =
+ raid5_compute_sector((sector_nr+conf->chunk_size/512)
+ *(conf->raid_disks-1) -1,
+ raid_disks, data_disks,
+ &dd_idx, &pd_idx, conf);
+ if (last_sector >= (mddev->size<<1))
+ last_sector = (mddev->size<<1)-1;
+ while (first_sector <= last_sector) {
+ pd_idx = stripe_to_pdidx(first_sector, conf, conf->previous_raid_disks);
+ sh = get_active_stripe(conf, first_sector,
+ conf->previous_raid_disks, pd_idx, 0);
+ set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
+ set_bit(STRIPE_HANDLE, &sh->state);
+ release_stripe(sh);
+ first_sector += STRIPE_SECTORS;
+ }
+ return conf->chunk_size>>9;
+ }
/* if there is 1 or more failed drives and we are trying
* to resync, then assert that we are finished, because there is
* nothing we can do.
@@ -1785,13 +1934,7 @@ static sector_t sync_request(mddev_t *md
return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
}
- x = sector_nr;
- chunk_offset = sector_div(x, sectors_per_chunk);
- stripe = x;
- BUG_ON(x != stripe);
-
- first_sector = raid5_compute_sector((sector_t)stripe*data_disks*sectors_per_chunk
- + chunk_offset, raid_disks, data_disks, &dd_idx, &pd_idx, conf);
+ pd_idx = stripe_to_pdidx(sector_nr, conf, raid_disks);
sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 1);
if (sh == NULL) {
sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 0);
diff ./include/linux/raid/md_k.h~current~ ./include/linux/raid/md_k.h
--- ./include/linux/raid/md_k.h~current~ 2006-01-24 10:39:55.000000000 +1100
+++ ./include/linux/raid/md_k.h 2006-01-24 10:39:49.000000000 +1100
@@ -157,6 +157,9 @@ struct mddev_s
* DONE: thread is done and is waiting to be reaped
* REQUEST: user-space has requested a sync (used with SYNC)
* CHECK: user-space request for for check-only, no repair
+ * RESHAPE: A reshape is happening
+ *
+ * If neither SYNC or RESHAPE are set, then it is a recovery.
*/
#define MD_RECOVERY_RUNNING 0
#define MD_RECOVERY_SYNC 1
@@ -166,6 +169,7 @@ struct mddev_s
#define MD_RECOVERY_NEEDED 5
#define MD_RECOVERY_REQUESTED 6
#define MD_RECOVERY_CHECK 7
+#define MD_RECOVERY_RESHAPE 8
unsigned long recovery;
int in_sync; /* know to not need resync */
diff ./include/linux/raid/raid5.h~current~ ./include/linux/raid/raid5.h
--- ./include/linux/raid/raid5.h~current~ 2006-01-24 10:39:55.000000000 +1100
+++ ./include/linux/raid/raid5.h 2006-01-24 10:39:49.000000000 +1100
@@ -157,6 +157,7 @@ struct stripe_head {
#define R5_ReadError 8 /* seen a read error here recently */
#define R5_ReWrite 9 /* have tried to over-write the readerror */
+#define R5_Expanded 10 /* This block now has post-expand data */
/*
* Write method
*/
@@ -176,7 +177,8 @@ struct stripe_head {
#define STRIPE_DEGRADED 7
#define STRIPE_BIT_DELAY 8
#define STRIPE_EXPANDING 9
-
+#define STRIPE_EXPAND_SOURCE 10
+#define STRIPE_EXPAND_READY 11
/*
* Plugging:
*
-
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