commit 1ffbe6941914a1413c53cc69ef357df920a1fc09
Author: Markus Stockhausen <markus.stockhausen@xxxxxxxxxxx>
Date: Sun Aug 10 09:44:43 2014 +0000
raid6: activate rmw feature
Glue it altogehter. The raid6 rmw path should work the same as the
already existing raid5 logic. So emulate the prexor handling/flags
and split functions as needed.
1) Split ops_run_prexor() into RAID4/5 and RAID6 logic. Xor the syndrome
at the start of a rmw run as we did it before for the single parity.
2) Take care of rmw run in ops_run_reconstruct6(). Again process only
the changed pages to get syndrome back into sync.
3) Enhance set_syndrome_sources() to fill NULL pages if we are in a rmw
run. The lower layers will calculate start & end pages from that and
call the xor_syndrome() correspondingly.
4) Adapt the several places where we ignored Q handling up to now.
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index c1a0dfe..7f66741 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1159,7 +1159,9 @@ ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
* destination buffer is recorded in srcs[count] and the Q destination
* is recorded in srcs[count+1]].
*/
-static int set_syndrome_sources(struct page **srcs, struct stripe_head *sh)
+static int set_syndrome_sources(struct page **srcs,
+ struct stripe_head *sh,
+ int srctype)
{
int disks = sh->disks;
int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
@@ -1174,8 +1176,15 @@ static int set_syndrome_sources(struct page **srcs, struct stripe_head *sh)
i = d0_idx;
do {
int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
+ struct r5dev *dev = &sh->dev[i];
- srcs[slot] = sh->dev[i].page;
+ if (i == sh->qd_idx || i == sh->pd_idx ||
+ (srctype == SYNDROME_SRC_ALL) ||
+ (srctype == SYNDROME_SRC_WANT_DRAIN &&
+ test_bit(R5_Wantdrain, &dev->flags)) ||
+ (srctype == SYNDROME_SRC_WRITTEN &&
+ dev->written))
+ srcs[slot] = sh->dev[i].page;
i = raid6_next_disk(i, disks);
} while (i != d0_idx);
@@ -1214,7 +1223,7 @@ ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
atomic_inc(&sh->count);
if (target == qd_idx) {
- count = set_syndrome_sources(blocks, sh);
+ count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
blocks[count] = NULL; /* regenerating p is not necessary */
BUG_ON(blocks[count+1] != dest); /* q should already be set */
init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
@@ -1321,7 +1330,7 @@ ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
&submit);
- count = set_syndrome_sources(blocks, sh);
+ count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
init_async_submit(&submit, ASYNC_TX_FENCE, tx,
ops_complete_compute, sh,
to_addr_conv(sh, percpu));
@@ -1356,7 +1365,7 @@ static void ops_complete_prexor(void *stripe_head_ref)
}
static struct dma_async_tx_descriptor *
-ops_run_prexor(struct stripe_head *sh, struct raid5_percpu *percpu,
+ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
struct dma_async_tx_descriptor *tx)
{
int disks = sh->disks;
@@ -1385,6 +1394,26 @@ ops_run_prexor(struct stripe_head *sh, struct raid5_percpu *percpu,
}
static struct dma_async_tx_descriptor *
+ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
+ struct dma_async_tx_descriptor *tx)
+{
+ struct page **blocks = percpu->scribble;
+ int count;
+ struct async_submit_ctl submit;
+
+ pr_debug("%s: stripe %llu\n", __func__,
+ (unsigned long long)sh->sector);
+
+ count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_WANT_DRAIN);
+
+ init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
+ ops_complete_prexor, sh, to_addr_conv(sh, percpu));
+ tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
+
+ return tx;
+}
+
+static struct dma_async_tx_descriptor *
ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
{
int disks = sh->disks;
@@ -1548,7 +1577,8 @@ ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
{
struct async_submit_ctl submit;
struct page **blocks = percpu->scribble;
- int count, i;
+ int count, i, synflags;
+ unsigned long txflags;
pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
@@ -1566,11 +1596,19 @@ ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
return;
}
- count = set_syndrome_sources(blocks, sh);
+ if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
+ synflags = SYNDROME_SRC_WRITTEN;
+ txflags = ASYNC_TX_ACK | ASYNC_TX_PQ_XOR_DST;
+ } else {
+ synflags = SYNDROME_SRC_ALL;
+ txflags = ASYNC_TX_ACK;
+ }
+
+ count = set_syndrome_sources(blocks, sh, synflags);
atomic_inc(&sh->count);
- init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_reconstruct,
+ init_async_submit(&submit, txflags, tx, ops_complete_reconstruct,
sh, to_addr_conv(sh, percpu));
async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
}
@@ -1630,7 +1668,7 @@ static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu
pr_debug("%s: stripe %llu checkp: %d\n", __func__,
(unsigned long long)sh->sector, checkp);
- count = set_syndrome_sources(srcs, sh);
+ count = set_syndrome_sources(srcs, sh, SYNDROME_SRC_ALL);
if (!checkp)
srcs[count] = NULL;
@@ -1671,8 +1709,12 @@ static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
async_tx_ack(tx);
}
- if (test_bit(STRIPE_OP_PREXOR, &ops_request))
- tx = ops_run_prexor(sh, percpu, tx);
+ if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {
+ if (level < 6)
+ tx = ops_run_prexor5(sh, percpu, tx);
+ else
+ tx = ops_run_prexor6(sh, percpu, tx);
+ }
if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
tx = ops_run_biodrain(sh, tx);
@@ -2542,7 +2584,7 @@ static void
schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
int rcw, int expand)
{
- int i, pd_idx = sh->pd_idx, disks = sh->disks;
+ int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
struct r5conf *conf = sh->raid_conf;
int level = conf->level;
@@ -2578,13 +2620,15 @@ schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
atomic_inc(&conf->pending_full_writes);
} else {
- BUG_ON(level == 6);
BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
+ BUG_ON(level == 6 &&
+ (!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
+ test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
- if (i == pd_idx)
+ if (i == pd_idx || i == qd_idx)
continue;
if (dev->towrite &&
@@ -3095,8 +3139,7 @@ static void handle_stripe_dirtying(struct r5conf *conf,
int rmw = 0, rcw = 0, i;
sector_t recovery_cp = conf->mddev->recovery_cp;
- /* RAID6 requires 'rcw' in current implementation.
- * Otherwise, check whether resync is now happening or should start.
+ /* Check whether resync is now happening or should start.
* If yes, then the array is dirty (after unclean shutdown or
* initial creation), so parity in some stripes might be inconsistent.
* In this case, we need to always do reconstruct-write, to ensure
@@ -3115,7 +3158,7 @@ static void handle_stripe_dirtying(struct r5conf *conf,
} else for (i = disks; i--; ) {
/* would I have to read this buffer for read_modify_write */
struct r5dev *dev = &sh->dev[i];
- if ((dev->towrite || i == sh->pd_idx) &&
+ if ((dev->towrite || i == sh->pd_idx || i == sh->qd_idx) &&
!test_bit(R5_LOCKED, &dev->flags) &&
!(test_bit(R5_UPTODATE, &dev->flags) ||
test_bit(R5_Wantcompute, &dev->flags))) {
@@ -3125,7 +3168,8 @@ static void handle_stripe_dirtying(struct r5conf *conf,
rmw += 2*disks; /* cannot read it */
}
/* Would I have to read this buffer for reconstruct_write */
- if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
+ if (!test_bit(R5_OVERWRITE, &dev->flags) &&
+ i != sh->pd_idx && i != sh->qd_idx &&
!test_bit(R5_LOCKED, &dev->flags) &&
!(test_bit(R5_UPTODATE, &dev->flags) ||
test_bit(R5_Wantcompute, &dev->flags))) {
@@ -3146,7 +3190,7 @@ static void handle_stripe_dirtying(struct r5conf *conf,
(unsigned long long)sh->sector, rmw);
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
- if ((dev->towrite || i == sh->pd_idx) &&
+ if ((dev->towrite || i == sh->pd_idx || i == sh->qd_idx) &&
!test_bit(R5_LOCKED, &dev->flags) &&
!(test_bit(R5_UPTODATE, &dev->flags) ||
test_bit(R5_Wantcompute, &dev->flags)) &&
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index 90a9097..437dfaa 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -349,6 +349,15 @@ enum {
PARITY_PREFER_RCW,
PARITY_PREFER_RMW,
};
+
+/*
+ * Pages requested from set_syndrome_sources()
+ */
+enum {
+ SYNDROME_SRC_ALL,
+ SYNDROME_SRC_WANT_DRAIN,
+ SYNDROME_SRC_WRITTEN,
+};
/*
* Plugging:
*
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