[md-accel PATCH 05/19] raid5: refactor handle_stripe5 and handle_stripe6 (v2)

Dan Williams
2007-06-27T01:53:55Z

handle_stripe5 and handle_stripe6 have very deep logic paths handling the
various states of a stripe_head. By introducing the 'stripe_head_state'
and 'r6_state' objects, large portions of the logic can be moved to
sub-routines.

'struct stripe_head_state' consumes all of the automatic variables that previously
stood alone in handle_stripe5,6. 'struct r6_state' contains the handle_stripe6
specific variables like p_failed and q_failed.

One of the nice side effects of the 'stripe_head_state' change is that it
allows for further reductions in code duplication between raid5 and raid6.
The following new routines are shared between raid5 and raid6:

handle_completed_write_requests
handle_requests_to_failed_array
handle_stripe_expansion

Changes in v2:
* fixed 'conf->raid_disk-1' for the raid6 'handle_stripe_expansion' path

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---

drivers/md/raid5.c | 1488 +++++++++++++++++++++-----------------------
include/linux/raid/raid5.h | 16
2 files changed, 737 insertions(+), 767 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 4f51dfa..94e0920 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1326,6 +1326,608 @@ static int stripe_to_pdidx(sector_t stripe, raid5_conf_t *conf, int disks)
return pd_idx;
}

+static void
+handle_requests_to_failed_array(raid5_conf_t *conf, struct stripe_head *sh,
+ struct stripe_head_state *s, int disks,
+ struct bio **return_bi)
+{
+ int i;
+ for (i = disks; i--; ) {
+ struct bio *bi;
+ int bitmap_end = 0;
+
+ if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
+ mdk_rdev_t *rdev;
+ rcu_read_lock();
+ rdev = rcu_dereference(conf->disks[i].rdev);
+ if (rdev && test_bit(In_sync, &rdev->flags))
+ /* multiple read failures in one stripe */
+ md_error(conf->mddev, rdev);
+ rcu_read_unlock();
+ }
+ spin_lock_irq(&conf->device_lock);
+ /* fail all writes first */
+ bi = sh->dev[i].towrite;
+ sh->dev[i].towrite = NULL;
+ if (bi) {
+ s->to_write--;
+ bitmap_end = 1;
+ }
+
+ if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
+ wake_up(&conf->wait_for_overlap);
+
+ while (bi && bi->bi_sector <
+ sh->dev[i].sector + STRIPE_SECTORS) {
+ struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
+ clear_bit(BIO_UPTODATE, &bi->bi_flags);
+ if (--bi->bi_phys_segments == 0) {
+ md_write_end(conf->mddev);
+ bi->bi_next = *return_bi;
+ *return_bi = bi;
+ }
+ bi = nextbi;
+ }
+ /* and fail all 'written' */
+ bi = sh->dev[i].written;
+ sh->dev[i].written = NULL;
+ if (bi) bitmap_end = 1;
+ while (bi && bi->bi_sector <
+ sh->dev[i].sector + STRIPE_SECTORS) {
+ struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
+ clear_bit(BIO_UPTODATE, &bi->bi_flags);
+ if (--bi->bi_phys_segments == 0) {
+ md_write_end(conf->mddev);
+ bi->bi_next = *return_bi;
+ *return_bi = bi;
+ }
+ bi = bi2;
+ }
+
+ /* fail any reads if this device is non-operational */
+ if (!test_bit(R5_Insync, &sh->dev[i].flags) ||
+ test_bit(R5_ReadError, &sh->dev[i].flags)) {
+ bi = sh->dev[i].toread;
+ sh->dev[i].toread = NULL;
+ if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
+ wake_up(&conf->wait_for_overlap);
+ if (bi) s->to_read--;
+ while (bi && bi->bi_sector <
+ sh->dev[i].sector + STRIPE_SECTORS) {
+ struct bio *nextbi =
+ r5_next_bio(bi, sh->dev[i].sector);
+ clear_bit(BIO_UPTODATE, &bi->bi_flags);
+ if (--bi->bi_phys_segments == 0) {
+ bi->bi_next = *return_bi;
+ *return_bi = bi;
+ }
+ bi = nextbi;
+ }
+ }
+ spin_unlock_irq(&conf->device_lock);
+ if (bitmap_end)
+ bitmap_endwrite(conf->mddev->bitmap, sh->sector,
+ STRIPE_SECTORS, 0, 0);
+ }
+
+}
+
+static void handle_issuing_new_read_requests5(struct stripe_head *sh,
+ struct stripe_head_state *s, int disks)
+{
+ int i;
+ for (i = disks; i--; ) {
+ struct r5dev *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)) ||
+ s->syncing || s->expanding ||
+ (s->failed && (sh->dev[s->failed_num].toread ||
+ (sh->dev[s->failed_num].towrite &&
+ !test_bit(R5_OVERWRITE, &sh->dev[s->failed_num].flags))
+ )))) {
+ /* we would like to get this block, possibly
+ * by computing it, but we might not be able to
+ */
+ if (s->uptodate == disks-1) {
+ PRINTK("Computing block %d\n", i);
+ compute_block(sh, i);
+ s->uptodate++;
+ } else if (test_bit(R5_Insync, &dev->flags)) {
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantread, &dev->flags);
+ s->locked++;
+ PRINTK("Reading block %d (sync=%d)\n",
+ i, s->syncing);
+ }
+ }
+ }
+ set_bit(STRIPE_HANDLE, &sh->state);
+}
+
+static void handle_issuing_new_read_requests6(struct stripe_head *sh,
+ struct stripe_head_state *s, struct r6_state *r6s,
+ int disks)
+{
+ int i;
+ for (i = disks; i--; ) {
+ struct r5dev *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)) ||
+ s->syncing || s->expanding ||
+ (s->failed >= 1 &&
+ (sh->dev[r6s->failed_num[0]].toread ||
+ s->to_write)) ||
+ (s->failed >= 2 &&
+ (sh->dev[r6s->failed_num[1]].toread ||
+ s->to_write)))) {
+ /* we would like to get this block, possibly
+ * by computing it, but we might not be able to
+ */
+ if (s->uptodate == disks-1) {
+ PRINTK("Computing stripe %llu block %d\n",
+ (unsigned long long)sh->sector, i);
+ compute_block_1(sh, i, 0);
+ s->uptodate++;
+ } else if ( s->uptodate == disks-2 && s->failed >= 2 ) {
+ /* Computing 2-failure is *very* expensive; only
+ * do it if failed >= 2
+ */
+ int other;
+ for (other = disks; other--; ) {
+ if (other == i)
+ continue;
+ if (!test_bit(R5_UPTODATE,
+ &sh->dev[other].flags))
+ break;
+ }
+ BUG_ON(other < 0);
+ PRINTK("Computing stripe %llu blocks %d,%d\n",
+ (unsigned long long)sh->sector,
+ i, other);
+ compute_block_2(sh, i, other);
+ s->uptodate += 2;
+ } else if (test_bit(R5_Insync, &dev->flags)) {
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantread, &dev->flags);
+ s->locked++;
+ PRINTK("Reading block %d (sync=%d)\n",
+ i, s->syncing);
+ }
+ }
+ }
+ set_bit(STRIPE_HANDLE, &sh->state);
+}
+
+
+/* handle_completed_write_requests
+ * any written block on an uptodate or failed drive can be returned.
+ * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
+ * never LOCKED, so we don't need to test 'failed' directly.
+ */
+static void handle_completed_write_requests(raid5_conf_t *conf,
+ struct stripe_head *sh, int disks, struct bio **return_bi)
+{
+ int i;
+ struct r5dev *dev;
+
+ for (i = disks; i--; )
+ if (sh->dev[i].written) {
+ dev = &sh->dev[i];
+ if (!test_bit(R5_LOCKED, &dev->flags) &&
+ test_bit(R5_UPTODATE, &dev->flags)) {
+ /* We can return any write requests */
+ struct bio *wbi, *wbi2;
+ int bitmap_end = 0;
+ PRINTK("Return write for disc %d\n", i);
+ spin_lock_irq(&conf->device_lock);
+ wbi = dev->written;
+ dev->written = NULL;
+ while (wbi && wbi->bi_sector <
+ dev->sector + STRIPE_SECTORS) {
+ wbi2 = r5_next_bio(wbi, dev->sector);
+ if (--wbi->bi_phys_segments == 0) {
+ md_write_end(conf->mddev);
+ wbi->bi_next = *return_bi;
+ *return_bi = wbi;
+ }
+ wbi = wbi2;
+ }
+ if (dev->towrite == NULL)
+ bitmap_end = 1;
+ spin_unlock_irq(&conf->device_lock);
+ if (bitmap_end)
+ bitmap_endwrite(conf->mddev->bitmap,
+ sh->sector,
+ STRIPE_SECTORS,
+ !test_bit(STRIPE_DEGRADED, &sh->state),
+ 0);
+ }
+ }
+}
+
+static void handle_issuing_new_write_requests5(raid5_conf_t *conf,
+ struct stripe_head *sh, struct stripe_head_state *s, int disks)
+{
+ int rmw = 0, rcw = 0, i;
+ 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) &&
+ !test_bit(R5_LOCKED, &dev->flags) &&
+ !test_bit(R5_UPTODATE, &dev->flags)) {
+ if (test_bit(R5_Insync, &dev->flags))
+ rmw++;
+ else
+ 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 &&
+ !test_bit(R5_LOCKED, &dev->flags) &&
+ !test_bit(R5_UPTODATE, &dev->flags)) {
+ if (test_bit(R5_Insync, &dev->flags))
+ rcw++;
+ else
+ rcw += 2*disks;
+ }
+ }
+ PRINTK("for sector %llu, rmw=%d rcw=%d\n",
+ (unsigned long long)sh->sector, rmw, rcw);
+ set_bit(STRIPE_HANDLE, &sh->state);
+ if (rmw < rcw && rmw > 0)
+ /* prefer read-modify-write, but need to get some data */
+ for (i = disks; i--; ) {
+ struct r5dev *dev = &sh->dev[i];
+ if ((dev->towrite || i == sh->pd_idx) &&
+ !test_bit(R5_LOCKED, &dev->flags) &&
+ !test_bit(R5_UPTODATE, &dev->flags) &&
+ test_bit(R5_Insync, &dev->flags)) {
+ if (
+ test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
+ PRINTK("Read_old block "
+ "%d for r-m-w\n", i);
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantread, &dev->flags);
+ s->locked++;
+ } else {
+ set_bit(STRIPE_DELAYED, &sh->state);
+ set_bit(STRIPE_HANDLE, &sh->state);
+ }
+ }
+ }
+ if (rcw <= rmw && rcw > 0)
+ /* want reconstruct write, but need to get some data */
+ for (i = disks; i--; ) {
+ struct r5dev *dev = &sh->dev[i];
+ if (!test_bit(R5_OVERWRITE, &dev->flags) &&
+ i != sh->pd_idx &&
+ !test_bit(R5_LOCKED, &dev->flags) &&
+ !test_bit(R5_UPTODATE, &dev->flags) &&
+ test_bit(R5_Insync, &dev->flags)) {
+ if (
+ test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
+ PRINTK("Read_old block "
+ "%d for Reconstruct\n", i);
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantread, &dev->flags);
+ s->locked++;
+ } else {
+ set_bit(STRIPE_DELAYED, &sh->state);
+ set_bit(STRIPE_HANDLE, &sh->state);
+ }
+ }
+ }
+ /* now if nothing is locked, and if we have enough data,
+ * we can start a write request
+ */
+ if (s->locked == 0 && (rcw == 0 || rmw == 0) &&
+ !test_bit(STRIPE_BIT_DELAY, &sh->state)) {
+ PRINTK("Computing parity...\n");
+ compute_parity5(sh, rcw == 0 ?
+ RECONSTRUCT_WRITE : READ_MODIFY_WRITE);
+ /* now every locked buffer is ready to be written */
+ for (i = disks; i--; )
+ if (test_bit(R5_LOCKED, &sh->dev[i].flags)) {
+ PRINTK("Writing block %d\n", i);
+ s->locked++;
+ set_bit(R5_Wantwrite, &sh->dev[i].flags);
+ if (!test_bit(R5_Insync, &sh->dev[i].flags)
+ || (i == sh->pd_idx && s->failed == 0))
+ set_bit(STRIPE_INSYNC, &sh->state);
+ }
+ if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
+ atomic_dec(&conf->preread_active_stripes);
+ if (atomic_read(&conf->preread_active_stripes) <
+ IO_THRESHOLD)
+ md_wakeup_thread(conf->mddev->thread);
+ }
+ }
+}
+
+static void handle_issuing_new_write_requests6(raid5_conf_t *conf,
+ struct stripe_head *sh, struct stripe_head_state *s,
+ struct r6_state *r6s, int disks)
+{
+ int rcw = 0, must_compute = 0, pd_idx = sh->pd_idx, i;
+ int qd_idx = r6s->qd_idx;
+ for (i = disks; i--; ) {
+ struct r5dev *dev = &sh->dev[i];
+ /* Would I have to read this buffer for reconstruct_write */
+ if (!test_bit(R5_OVERWRITE, &dev->flags)
+ && i != pd_idx && i != qd_idx
+ && (!test_bit(R5_LOCKED, &dev->flags)
+ ) &&
+ !test_bit(R5_UPTODATE, &dev->flags)) {
+ if (test_bit(R5_Insync, &dev->flags)) rcw++;
+ else {
+ PRINTK("raid6: must_compute: "
+ "disk %d flags=%#lx\n", i, dev->flags);
+ must_compute++;
+ }
+ }
+ }
+ PRINTK("for sector %llu, rcw=%d, must_compute=%d\n",
+ (unsigned long long)sh->sector, rcw, must_compute);
+ set_bit(STRIPE_HANDLE, &sh->state);
+
+ if (rcw > 0)
+ /* want reconstruct write, but need to get some data */
+ for (i = disks; i--; ) {
+ struct r5dev *dev = &sh->dev[i];
+ if (!test_bit(R5_OVERWRITE, &dev->flags)
+ && !(s->failed == 0 && (i == pd_idx || i == qd_idx))
+ && !test_bit(R5_LOCKED, &dev->flags) &&
+ !test_bit(R5_UPTODATE, &dev->flags) &&
+ test_bit(R5_Insync, &dev->flags)) {
+ if (
+ test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
+ PRINTK("Read_old stripe %llu "
+ "block %d for Reconstruct\n",
+ (unsigned long long)sh->sector, i);
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantread, &dev->flags);
+ s->locked++;
+ } else {
+ PRINTK("Request delayed stripe %llu "
+ "block %d for Reconstruct\n",
+ (unsigned long long)sh->sector, i);
+ set_bit(STRIPE_DELAYED, &sh->state);
+ set_bit(STRIPE_HANDLE, &sh->state);
+ }
+ }
+ }
+ /* now if nothing is locked, and if we have enough data, we can start a
+ * write request
+ */
+ if (s->locked == 0 && rcw == 0 &&
+ !test_bit(STRIPE_BIT_DELAY, &sh->state)) {
+ if (must_compute > 0) {
+ /* We have failed blocks and need to compute them */
+ switch (s->failed) {
+ case 0:
+ BUG();
+ case 1:
+ compute_block_1(sh, r6s->failed_num[0], 0);
+ break;
+ case 2:
+ compute_block_2(sh, r6s->failed_num[0],
+ r6s->failed_num[1]);
+ break;
+ default: /* This request should have been failed? */
+ BUG();
+ }
+ }
+
+ PRINTK("Computing parity for stripe %llu\n",
+ (unsigned long long)sh->sector);
+ compute_parity6(sh, RECONSTRUCT_WRITE);
+ /* now every locked buffer is ready to be written */
+ for (i = disks; i--; )
+ if (test_bit(R5_LOCKED, &sh->dev[i].flags)) {
+ PRINTK("Writing stripe %llu block %d\n",
+ (unsigned long long)sh->sector, i);
+ s->locked++;
+ set_bit(R5_Wantwrite, &sh->dev[i].flags);
+ }
+ /* after a RECONSTRUCT_WRITE, the stripe MUST be in-sync */
+ set_bit(STRIPE_INSYNC, &sh->state);
+
+ if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
+ atomic_dec(&conf->preread_active_stripes);
+ if (atomic_read(&conf->preread_active_stripes) <
+ IO_THRESHOLD)
+ md_wakeup_thread(conf->mddev->thread);
+ }
+ }
+}
+
+static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh,
+ struct stripe_head_state *s, int disks)
+{
+ set_bit(STRIPE_HANDLE, &sh->state);
+ if (s->failed == 0) {
+ BUG_ON(s->uptodate != disks);
+ compute_parity5(sh, CHECK_PARITY);
+ s->uptodate--;
+ if (page_is_zero(sh->dev[sh->pd_idx].page)) {
+ /* parity is correct (on disc, not in buffer any more)
+ */
+ set_bit(STRIPE_INSYNC, &sh->state);
+ } else {
+ conf->mddev->resync_mismatches += STRIPE_SECTORS;
+ if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
+ /* don't try to repair!! */
+ set_bit(STRIPE_INSYNC, &sh->state);
+ else {
+ compute_block(sh, sh->pd_idx);
+ s->uptodate++;
+ }
+ }
+ }
+ if (!test_bit(STRIPE_INSYNC, &sh->state)) {
+ struct r5dev *dev;
+ /* either failed parity check, or recovery is happening */
+ if (s->failed == 0)
+ s->failed_num = sh->pd_idx;
+ dev = &sh->dev[s->failed_num];
+ BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
+ BUG_ON(s->uptodate != disks);
+
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantwrite, &dev->flags);
+ clear_bit(STRIPE_DEGRADED, &sh->state);
+ s->locked++;
+ set_bit(STRIPE_INSYNC, &sh->state);
+ }
+}
+
+
+static void handle_parity_checks6(raid5_conf_t *conf, struct stripe_head *sh,
+ struct stripe_head_state *s,
+ struct r6_state *r6s, struct page *tmp_page,
+ int disks)
+{
+ int update_p = 0, update_q = 0;
+ struct r5dev *dev;
+ int pd_idx = sh->pd_idx;
+ int qd_idx = r6s->qd_idx;
+
+ set_bit(STRIPE_HANDLE, &sh->state);
+
+ BUG_ON(s->failed > 2);
+ BUG_ON(s->uptodate < disks);
+ /* Want to check and possibly repair P and Q.
+ * However there could be one 'failed' device, in which
+ * case we can only check one of them, possibly using the
+ * other to generate missing data
+ */
+
+ /* If !tmp_page, we cannot do the calculations,
+ * but as we have set STRIPE_HANDLE, we will soon be called
+ * by stripe_handle with a tmp_page - just wait until then.
+ */
+ if (tmp_page) {
+ if (s->failed == r6s->q_failed) {
+ /* The only possible failed device holds 'Q', so it
+ * makes sense to check P (If anything else were failed,
+ * we would have used P to recreate it).
+ */
+ compute_block_1(sh, pd_idx, 1);
+ if (!page_is_zero(sh->dev[pd_idx].page)) {
+ compute_block_1(sh, pd_idx, 0);
+ update_p = 1;
+ }
+ }
+ if (!r6s->q_failed && s->failed < 2) {
+ /* q is not failed, and we didn't use it to generate
+ * anything, so it makes sense to check it
+ */
+ memcpy(page_address(tmp_page),
+ page_address(sh->dev[qd_idx].page),
+ STRIPE_SIZE);
+ compute_parity6(sh, UPDATE_PARITY);
+ if (memcmp(page_address(tmp_page),
+ page_address(sh->dev[qd_idx].page),
+ STRIPE_SIZE) != 0) {
+ clear_bit(STRIPE_INSYNC, &sh->state);
+ update_q = 1;
+ }
+ }
+ if (update_p || update_q) {
+ conf->mddev->resync_mismatches += STRIPE_SECTORS;
+ if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
+ /* don't try to repair!! */
+ update_p = update_q = 0;
+ }
+
+ /* now write out any block on a failed drive,
+ * or P or Q if they need it
+ */
+
+ if (s->failed == 2) {
+ dev = &sh->dev[r6s->failed_num[1]];
+ s->locked++;
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantwrite, &dev->flags);
+ }
+ if (s->failed >= 1) {
+ dev = &sh->dev[r6s->failed_num[0]];
+ s->locked++;
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantwrite, &dev->flags);
+ }
+
+ if (update_p) {
+ dev = &sh->dev[pd_idx];
+ s->locked++;
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantwrite, &dev->flags);
+ }
+ if (update_q) {
+ dev = &sh->dev[qd_idx];
+ s->locked++;
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantwrite, &dev->flags);
+ }
+ clear_bit(STRIPE_DEGRADED, &sh->state);
+
+ set_bit(STRIPE_INSYNC, &sh->state);
+ }
+}
+
+static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh,
+ struct r6_state *r6s)
+{
+ int i;
+
+ /* 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 && (r6s && i != r6s->qd_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 -
+ conf->max_degraded, &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 &&
+ (r6s && j != r6s->qd_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);
+ }
+}

/*
* handle_stripe - do things to a stripe.
@@ -1344,20 +1946,16 @@ static int stripe_to_pdidx(sector_t stripe, raid5_conf_t *conf, int disks)
* get BH_Lock set before the stripe lock is released.
*
*/
-
+
static void handle_stripe5(struct stripe_head *sh)
{
raid5_conf_t *conf = sh->raid_conf;
- int disks = sh->disks;
- struct bio *return_bi= NULL;
- struct bio *bi;
- int i;
- 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;
+ int disks = sh->disks, i;
+ struct bio *return_bi = NULL, *bi;
+ struct stripe_head_state s;
struct r5dev *dev;

+ memset(&s, 0, sizeof(s));
PRINTK("handling stripe %llu, cnt=%d, pd_idx=%d\n",
(unsigned long long)sh->sector, atomic_read(&sh->count),
sh->pd_idx);
@@ -1366,15 +1964,15 @@ static void handle_stripe5(struct stripe_head *sh)
clear_bit(STRIPE_HANDLE, &sh->state);
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);
+ s.syncing = test_bit(STRIPE_SYNCING, &sh->state);
+ s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
+ s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
/* Now to look around and see what can be done */

rcu_read_lock();
for (i=disks; i--; ) {
mdk_rdev_t *rdev;
- dev = &sh->dev[i];
+ struct r5dev *dev = &sh->dev[i];
clear_bit(R5_Insync, &dev->flags);

PRINTK("check %d: state 0x%lx read %p write %p written %p\n",
@@ -1403,17 +2001,18 @@ static void handle_stripe5(struct stripe_head *sh)
}

/* now count some things */
- if (test_bit(R5_LOCKED, &dev->flags)) locked++;
- if (test_bit(R5_UPTODATE, &dev->flags)) uptodate++;
+ if (test_bit(R5_LOCKED, &dev->flags)) s.locked++;
+ if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++;

-
- if (dev->toread) to_read++;
+ if (dev->toread)
+ s.to_read++;
if (dev->towrite) {
- to_write++;
+ s.to_write++;
if (!test_bit(R5_OVERWRITE, &dev->flags))
- non_overwrite++;
+ s.non_overwrite++;
}
- if (dev->written) written++;
+ if (dev->written)
+ s.written++;
rdev = rcu_dereference(conf->disks[i].rdev);
if (!rdev || !test_bit(In_sync, &rdev->flags)) {
/* The ReadError flag will just be confusing now */
@@ -1422,306 +2021,59 @@ static void handle_stripe5(struct stripe_head *sh)
}
if (!rdev || !test_bit(In_sync, &rdev->flags)
|| test_bit(R5_ReadError, &dev->flags)) {
- failed++;
- failed_num = i;
+ s.failed++;
+ s.failed_num = i;
} else
set_bit(R5_Insync, &dev->flags);
}
rcu_read_unlock();
PRINTK("locked=%d uptodate=%d to_read=%d"
" to_write=%d failed=%d failed_num=%d\n",
- locked, uptodate, to_read, to_write, failed, failed_num);
+ s.locked, s.uptodate, s.to_read, s.to_write,
+ s.failed, s.failed_num);
/* check if the array has lost two devices and, if so, some requests might
* need to be failed
*/
- if (failed > 1 && to_read+to_write+written) {
- for (i=disks; i--; ) {
- int bitmap_end = 0;
-
- if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
- mdk_rdev_t *rdev;
- rcu_read_lock();
- rdev = rcu_dereference(conf->disks[i].rdev);
- if (rdev && test_bit(In_sync, &rdev->flags))
- /* multiple read failures in one stripe */
- md_error(conf->mddev, rdev);
- rcu_read_unlock();
- }
-
- spin_lock_irq(&conf->device_lock);
- /* fail all writes first */
- bi = sh->dev[i].towrite;
- sh->dev[i].towrite = NULL;
- if (bi) { to_write--; bitmap_end = 1; }
-
- if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
- wake_up(&conf->wait_for_overlap);
-
- while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){
- struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
- clear_bit(BIO_UPTODATE, &bi->bi_flags);
- if (--bi->bi_phys_segments == 0) {
- md_write_end(conf->mddev);
- bi->bi_next = return_bi;
- return_bi = bi;
- }
- bi = nextbi;
- }
- /* and fail all 'written' */
- bi = sh->dev[i].written;
- sh->dev[i].written = NULL;
- if (bi) bitmap_end = 1;
- while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS) {
- struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
- clear_bit(BIO_UPTODATE, &bi->bi_flags);
- if (--bi->bi_phys_segments == 0) {
- md_write_end(conf->mddev);
- bi->bi_next = return_bi;
- return_bi = bi;
- }
- bi = bi2;
- }
-
- /* fail any reads if this device is non-operational */
- if (!test_bit(R5_Insync, &sh->dev[i].flags) ||
- test_bit(R5_ReadError, &sh->dev[i].flags)) {
- bi = sh->dev[i].toread;
- sh->dev[i].toread = NULL;
- if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
- wake_up(&conf->wait_for_overlap);
- if (bi) to_read--;
- while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){
- struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
- clear_bit(BIO_UPTODATE, &bi->bi_flags);
- if (--bi->bi_phys_segments == 0) {
- bi->bi_next = return_bi;
- return_bi = bi;
- }
- bi = nextbi;
- }
- }
- spin_unlock_irq(&conf->device_lock);
- if (bitmap_end)
- bitmap_endwrite(conf->mddev->bitmap, sh->sector,
- STRIPE_SECTORS, 0, 0);
- }
- }
- if (failed > 1 && syncing) {
+ if (s.failed > 1 && s.to_read+s.to_write+s.written)
+ handle_requests_to_failed_array(conf, sh, &s, disks,
+ &return_bi);
+ if (s.failed > 1 && s.syncing) {
md_done_sync(conf->mddev, STRIPE_SECTORS,0);
clear_bit(STRIPE_SYNCING, &sh->state);
- syncing = 0;
+ s.syncing = 0;
}

/* might be able to return some write requests if the parity block
* is safe, or on a failed drive
*/
dev = &sh->dev[sh->pd_idx];
- if ( written &&
- ( (test_bit(R5_Insync, &dev->flags) && !test_bit(R5_LOCKED, &dev->flags) &&
- test_bit(R5_UPTODATE, &dev->flags))
- || (failed == 1 && failed_num == sh->pd_idx))
- ) {
- /* any written block on an uptodate or failed drive can be returned.
- * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
- * never LOCKED, so we don't need to test 'failed' directly.
- */
- for (i=disks; i--; )
- if (sh->dev[i].written) {
- dev = &sh->dev[i];
- if (!test_bit(R5_LOCKED, &dev->flags) &&
- test_bit(R5_UPTODATE, &dev->flags) ) {
- /* We can return any write requests */
- struct bio *wbi, *wbi2;
- int bitmap_end = 0;
- PRINTK("Return write for disc %d\n", i);
- spin_lock_irq(&conf->device_lock);
- wbi = dev->written;
- dev->written = NULL;
- while (wbi && wbi->bi_sector < dev->sector + STRIPE_SECTORS) {
- wbi2 = r5_next_bio(wbi, dev->sector);
- if (--wbi->bi_phys_segments == 0) {
- md_write_end(conf->mddev);
- wbi->bi_next = return_bi;
- return_bi = wbi;
- }
- wbi = wbi2;
- }
- if (dev->towrite == NULL)
- bitmap_end = 1;
- spin_unlock_irq(&conf->device_lock);
- if (bitmap_end)
- bitmap_endwrite(conf->mddev->bitmap, sh->sector,
- STRIPE_SECTORS,
- !test_bit(STRIPE_DEGRADED, &sh->state), 0);
- }
- }
- }
+ if ( s.written &&
+ ((test_bit(R5_Insync, &dev->flags) &&
+ !test_bit(R5_LOCKED, &dev->flags) &&
+ test_bit(R5_UPTODATE, &dev->flags)) ||
+ (s.failed == 1 && s.failed_num == sh->pd_idx)))
+ handle_completed_write_requests(conf, sh, disks, &return_bi);

/* Now we might consider reading some blocks, either to check/generate
* parity, or to satisfy requests
* or to load a block that is being partially written.
*/
- 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))))
- )
- ) {
- /* we would like to get this block, possibly
- * by computing it, but we might not be able to
- */
- if (uptodate == disks-1) {
- PRINTK("Computing block %d\n", i);
- compute_block(sh, i);
- uptodate++;
- } else if (test_bit(R5_Insync, &dev->flags)) {
- set_bit(R5_LOCKED, &dev->flags);
- set_bit(R5_Wantread, &dev->flags);
- locked++;
- PRINTK("Reading block %d (sync=%d)\n",
- i, syncing);
- }
- }
- }
- set_bit(STRIPE_HANDLE, &sh->state);
- }
+ if (s.to_read || s.non_overwrite ||
+ (s.syncing && (s.uptodate < disks)) || s.expanding)
+ handle_issuing_new_read_requests5(sh, &s, disks);

/* now to consider writing and what else, if anything should be read */
- if (to_write) {
- int rmw=0, rcw=0;
- for (i=disks ; i--;) {
- /* would I have to read this buffer for read_modify_write */
- dev = &sh->dev[i];
- if ((dev->towrite || i == sh->pd_idx) &&
- (!test_bit(R5_LOCKED, &dev->flags)
- ) &&
- !test_bit(R5_UPTODATE, &dev->flags)) {
- if (test_bit(R5_Insync, &dev->flags)
-/* && !(!mddev->insync && i == sh->pd_idx) */
- )
- rmw++;
- else 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 &&
- (!test_bit(R5_LOCKED, &dev->flags)
- ) &&
- !test_bit(R5_UPTODATE, &dev->flags)) {
- if (test_bit(R5_Insync, &dev->flags)) rcw++;
- else rcw += 2*disks;
- }
- }
- PRINTK("for sector %llu, rmw=%d rcw=%d\n",
- (unsigned long long)sh->sector, rmw, rcw);
- set_bit(STRIPE_HANDLE, &sh->state);
- if (rmw < rcw && rmw > 0)
- /* prefer read-modify-write, but need to get some data */
- for (i=disks; i--;) {
- dev = &sh->dev[i];
- if ((dev->towrite || i == sh->pd_idx) &&
- !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&
- test_bit(R5_Insync, &dev->flags)) {
- if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
- {
- PRINTK("Read_old block %d for r-m-w\n", i);
- set_bit(R5_LOCKED, &dev->flags);
- set_bit(R5_Wantread, &dev->flags);
- locked++;
- } else {
- set_bit(STRIPE_DELAYED, &sh->state);
- set_bit(STRIPE_HANDLE, &sh->state);
- }
- }
- }
- if (rcw <= rmw && rcw > 0)
- /* want reconstruct write, but need to get some data */
- for (i=disks; i--;) {
- dev = &sh->dev[i];
- if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
- !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&
- test_bit(R5_Insync, &dev->flags)) {
- if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
- {
- PRINTK("Read_old block %d for Reconstruct\n", i);
- set_bit(R5_LOCKED, &dev->flags);
- set_bit(R5_Wantread, &dev->flags);
- locked++;
- } else {
- set_bit(STRIPE_DELAYED, &sh->state);
- set_bit(STRIPE_HANDLE, &sh->state);
- }
- }
- }
- /* now if nothing is locked, and if we have enough data, we can start a write request */
- if (locked == 0 && (rcw == 0 ||rmw == 0) &&
- !test_bit(STRIPE_BIT_DELAY, &sh->state)) {
- PRINTK("Computing parity...\n");
- compute_parity5(sh, rcw==0 ? RECONSTRUCT_WRITE : READ_MODIFY_WRITE);
- /* now every locked buffer is ready to be written */
- for (i=disks; i--;)
- if (test_bit(R5_LOCKED, &sh->dev[i].flags)) {
- PRINTK("Writing block %d\n", i);
- locked++;
- set_bit(R5_Wantwrite, &sh->dev[i].flags);
- if (!test_bit(R5_Insync, &sh->dev[i].flags)
- || (i==sh->pd_idx && failed == 0))
- set_bit(STRIPE_INSYNC, &sh->state);
- }
- if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
- atomic_dec(&conf->preread_active_stripes);
- if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
- md_wakeup_thread(conf->mddev->thread);
- }
- }
- }
+ if (s.to_write)
+ handle_issuing_new_write_requests5(conf, sh, &s, disks);

/* maybe we need to check and possibly fix the parity for this stripe
* Any reads will already have been scheduled, so we just see if enough data
* is available
*/
- if (syncing && locked == 0 &&
- !test_bit(STRIPE_INSYNC, &sh->state)) {
- set_bit(STRIPE_HANDLE, &sh->state);
- if (failed == 0) {
- BUG_ON(uptodate != disks);
- compute_parity5(sh, CHECK_PARITY);
- uptodate--;
- if (page_is_zero(sh->dev[sh->pd_idx].page)) {
- /* parity is correct (on disc, not in buffer any more) */
- set_bit(STRIPE_INSYNC, &sh->state);
- } else {
- conf->mddev->resync_mismatches += STRIPE_SECTORS;
- if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
- /* don't try to repair!! */
- set_bit(STRIPE_INSYNC, &sh->state);
- else {
- compute_block(sh, sh->pd_idx);
- uptodate++;
- }
- }
- }
- if (!test_bit(STRIPE_INSYNC, &sh->state)) {
- /* either failed parity check, or recovery is happening */
- if (failed==0)
- failed_num = sh->pd_idx;
- dev = &sh->dev[failed_num];
- BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
- BUG_ON(uptodate != disks);
-
- set_bit(R5_LOCKED, &dev->flags);
- set_bit(R5_Wantwrite, &dev->flags);
- clear_bit(STRIPE_DEGRADED, &sh->state);
- locked++;
- set_bit(STRIPE_INSYNC, &sh->state);
- }
- }
- if (syncing && locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
+ if (s.syncing && s.locked == 0 &&
+ !test_bit(STRIPE_INSYNC, &sh->state))
+ handle_parity_checks5(conf, sh, &s, disks);
+ if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
md_done_sync(conf->mddev, STRIPE_SECTORS,1);
clear_bit(STRIPE_SYNCING, &sh->state);
}
@@ -1729,86 +2081,45 @@ static void handle_stripe5(struct stripe_head *sh)
/* If the failed drive is just a ReadError, then we might need to progress
* the repair/check process
*/
- if (failed == 1 && ! conf->mddev->ro &&
- test_bit(R5_ReadError, &sh->dev[failed_num].flags)
- && !test_bit(R5_LOCKED, &sh->dev[failed_num].flags)
- && test_bit(R5_UPTODATE, &sh->dev[failed_num].flags)
+ if (s.failed == 1 && !conf->mddev->ro &&
+ test_bit(R5_ReadError, &sh->dev[s.failed_num].flags)
+ && !test_bit(R5_LOCKED, &sh->dev[s.failed_num].flags)
+ && test_bit(R5_UPTODATE, &sh->dev[s.failed_num].flags)
) {
- dev = &sh->dev[failed_num];
+ dev = &sh->dev[s.failed_num];
if (!test_bit(R5_ReWrite, &dev->flags)) {
set_bit(R5_Wantwrite, &dev->flags);
set_bit(R5_ReWrite, &dev->flags);
set_bit(R5_LOCKED, &dev->flags);
- locked++;
+ s.locked++;
} else {
/* let's read it back */
set_bit(R5_Wantread, &dev->flags);
set_bit(R5_LOCKED, &dev->flags);
- locked++;
+ s.locked++;
}
}

- if (expanded && test_bit(STRIPE_EXPANDING, &sh->state)) {
+ if (s.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_parity5(sh, RECONSTRUCT_WRITE);
- for (i= conf->raid_disks; i--;) {
+ for (i = conf->raid_disks; i--; ) {
set_bit(R5_LOCKED, &sh->dev[i].flags);
- locked++;
+ s.locked++;
set_bit(R5_Wantwrite, &sh->dev[i].flags);
}
clear_bit(STRIPE_EXPANDING, &sh->state);
- } else if (expanded) {
+ } else if (s.expanded) {
clear_bit(STRIPE_EXPAND_READY, &sh->state);
atomic_dec(&conf->reshape_stripes);
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);
- }
- }
+ if (s.expanding && s.locked == 0)
+ handle_stripe_expansion(conf, sh, NULL);

spin_unlock(&sh->lock);

@@ -1850,7 +2161,7 @@ static void handle_stripe5(struct stripe_head *sh)
rcu_read_unlock();

if (rdev) {
- if (syncing || expanding || expanded)
+ if (s.syncing || s.expanding || s.expanded)
md_sync_acct(rdev->bdev, STRIPE_SECTORS);

bi->bi_bdev = rdev->bdev;
@@ -1886,29 +2197,27 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
{
raid6_conf_t *conf = sh->raid_conf;
int disks = sh->disks;
- struct bio *return_bi= NULL;
+ struct bio *return_bi = NULL;
struct bio *bi;
- int i;
- 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[2] = {0, 0};
+ int i, pd_idx = sh->pd_idx;
+ struct stripe_head_state s;
+ struct r6_state r6s;
struct r5dev *dev, *pdev, *qdev;
- int pd_idx = sh->pd_idx;
- int qd_idx = raid6_next_disk(pd_idx, disks);
- int p_failed, q_failed;

- PRINTK("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d, qd_idx=%d\n",
- (unsigned long long)sh->sector, sh->state, atomic_read(&sh->count),
- pd_idx, qd_idx);
+ r6s.qd_idx = raid6_next_disk(pd_idx, disks);
+ PRINTK("handling stripe %llu, state=%#lx cnt=%d, "
+ "pd_idx=%d, qd_idx=%d\n",
+ (unsigned long long)sh->sector, sh->state,
+ atomic_read(&sh->count), pd_idx, r6s.qd_idx);
+ memset(&s, 0, sizeof(s));

spin_lock(&sh->lock);
clear_bit(STRIPE_HANDLE, &sh->state);
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);
+ s.syncing = test_bit(STRIPE_SYNCING, &sh->state);
+ s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
+ s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
/* Now to look around and see what can be done */

rcu_read_lock();
@@ -1943,17 +2252,19 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
}

/* now count some things */
- if (test_bit(R5_LOCKED, &dev->flags)) locked++;
- if (test_bit(R5_UPTODATE, &dev->flags)) uptodate++;
+ if (test_bit(R5_LOCKED, &dev->flags)) s.locked++;
+ if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++;

- if (dev->toread) to_read++;
+ if (dev->toread)
+ s.to_read++;
if (dev->towrite) {
- to_write++;
+ s.to_write++;
if (!test_bit(R5_OVERWRITE, &dev->flags))
- non_overwrite++;
+ s.non_overwrite++;
}
- if (dev->written) written++;
+ if (dev->written)
+ s.written++;
rdev = rcu_dereference(conf->disks[i].rdev);
if (!rdev || !test_bit(In_sync, &rdev->flags)) {
/* The ReadError flag will just be confusing now */
@@ -1962,96 +2273,27 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
}
if (!rdev || !test_bit(In_sync, &rdev->flags)
|| test_bit(R5_ReadError, &dev->flags)) {
- if ( failed < 2 )
- failed_num[failed] = i;
- failed++;
+ if (s.failed < 2)
+ r6s.failed_num[s.failed] = i;
+ s.failed++;
} else
set_bit(R5_Insync, &dev->flags);
}
rcu_read_unlock();
PRINTK("locked=%d uptodate=%d to_read=%d"
" to_write=%d failed=%d failed_num=%d,%d\n",
- locked, uptodate, to_read, to_write, failed,
- failed_num[0], failed_num[1]);
- /* check if the array has lost >2 devices and, if so, some requests might
- * need to be failed
+ s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
+ r6s.failed_num[0], r6s.failed_num[1]);
+ /* check if the array has lost >2 devices and, if so, some requests
+ * might need to be failed
*/
- if (failed > 2 && to_read+to_write+written) {
- for (i=disks; i--; ) {
- int bitmap_end = 0;
-
- if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
- mdk_rdev_t *rdev;
- rcu_read_lock();
- rdev = rcu_dereference(conf->disks[i].rdev);
- if (rdev && test_bit(In_sync, &rdev->flags))
- /* multiple read failures in one stripe */
- md_error(conf->mddev, rdev);
- rcu_read_unlock();
- }
-
- spin_lock_irq(&conf->device_lock);
- /* fail all writes first */
- bi = sh->dev[i].towrite;
- sh->dev[i].towrite = NULL;
- if (bi) { to_write--; bitmap_end = 1; }
-
- if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
- wake_up(&conf->wait_for_overlap);
-
- while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){
- struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
- clear_bit(BIO_UPTODATE, &bi->bi_flags);
- if (--bi->bi_phys_segments == 0) {
- md_write_end(conf->mddev);
- bi->bi_next = return_bi;
- return_bi = bi;
- }
- bi = nextbi;
- }
- /* and fail all 'written' */
- bi = sh->dev[i].written;
- sh->dev[i].written = NULL;
- if (bi) bitmap_end = 1;
- while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS) {
- struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
- clear_bit(BIO_UPTODATE, &bi->bi_flags);
- if (--bi->bi_phys_segments == 0) {
- md_write_end(conf->mddev);
- bi->bi_next = return_bi;
- return_bi = bi;
- }
- bi = bi2;
- }
-
- /* fail any reads if this device is non-operational */
- if (!test_bit(R5_Insync, &sh->dev[i].flags) ||
- test_bit(R5_ReadError, &sh->dev[i].flags)) {
- bi = sh->dev[i].toread;
- sh->dev[i].toread = NULL;
- if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
- wake_up(&conf->wait_for_overlap);
- if (bi) to_read--;
- while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){
- struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
- clear_bit(BIO_UPTODATE, &bi->bi_flags);
- if (--bi->bi_phys_segments == 0) {
- bi->bi_next = return_bi;
- return_bi = bi;
- }
- bi = nextbi;
- }
- }
- spin_unlock_irq(&conf->device_lock);
- if (bitmap_end)
- bitmap_endwrite(conf->mddev->bitmap, sh->sector,
- STRIPE_SECTORS, 0, 0);
- }
- }
- if (failed > 2 && syncing) {
+ if (s.failed > 2 && s.to_read+s.to_write+s.written)
+ handle_requests_to_failed_array(conf, sh, &s, disks,
+ &return_bi);
+ if (s.failed > 2 && s.syncing) {
md_done_sync(conf->mddev, STRIPE_SECTORS,0);
clear_bit(STRIPE_SYNCING, &sh->state);
- syncing = 0;
+ s.syncing = 0;
}

/*
@@ -2059,279 +2301,41 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
* are safe, or on a failed drive
*/
pdev = &sh->dev[pd_idx];
- p_failed = (failed >= 1 && failed_num[0] == pd_idx)
- || (failed >= 2 && failed_num[1] == pd_idx);
- qdev = &sh->dev[qd_idx];
- q_failed = (failed >= 1 && failed_num[0] == qd_idx)
- || (failed >= 2 && failed_num[1] == qd_idx);
-
- if ( written &&
- ( p_failed || ((test_bit(R5_Insync, &pdev->flags)
+ r6s.p_failed = (s.failed >= 1 && r6s.failed_num[0] == pd_idx)
+ || (s.failed >= 2 && r6s.failed_num[1] == pd_idx);
+ qdev = &sh->dev[r6s.qd_idx];
+ r6s.q_failed = (s.failed >= 1 && r6s.failed_num[0] == r6s.qd_idx)
+ || (s.failed >= 2 && r6s.failed_num[1] == r6s.qd_idx);
+
+ if ( s.written &&
+ ( r6s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
&& !test_bit(R5_LOCKED, &pdev->flags)
- && test_bit(R5_UPTODATE, &pdev->flags))) ) &&
- ( q_failed || ((test_bit(R5_Insync, &qdev->flags)
+ && test_bit(R5_UPTODATE, &pdev->flags)))) &&
+ ( r6s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
&& !test_bit(R5_LOCKED, &qdev->flags)
- && test_bit(R5_UPTODATE, &qdev->flags))) ) ) {
- /* any written block on an uptodate or failed drive can be
- * returned. Note that if we 'wrote' to a failed drive,
- * it will be UPTODATE, but never LOCKED, so we don't need
- * to test 'failed' directly.
- */
- for (i=disks; i--; )
- if (sh->dev[i].written) {
- dev = &sh->dev[i];
- if (!test_bit(R5_LOCKED, &dev->flags) &&
- test_bit(R5_UPTODATE, &dev->flags) ) {
- /* We can return any write requests */
- int bitmap_end = 0;
- struct bio *wbi, *wbi2;
- PRINTK("Return write for stripe %llu disc %d\n",
- (unsigned long long)sh->sector, i);
- spin_lock_irq(&conf->device_lock);
- wbi = dev->written;
- dev->written = NULL;
- while (wbi && wbi->bi_sector < dev->sector + STRIPE_SECTORS) {
- wbi2 = r5_next_bio(wbi, dev->sector);
- if (--wbi->bi_phys_segments == 0) {
- md_write_end(conf->mddev);
- wbi->bi_next = return_bi;
- return_bi = wbi;
- }
- wbi = wbi2;
- }
- if (dev->towrite == NULL)
- bitmap_end = 1;
- spin_unlock_irq(&conf->device_lock);
- if (bitmap_end)
- bitmap_endwrite(conf->mddev->bitmap, sh->sector,
- STRIPE_SECTORS,
- !test_bit(STRIPE_DEGRADED, &sh->state), 0);
- }
- }
- }
+ && test_bit(R5_UPTODATE, &qdev->flags)))))
+ handle_completed_write_requests(conf, sh, disks, &return_bi);

/* Now we might consider reading some blocks, either to check/generate
* parity, or to satisfy requests
* or to load a block that is being partially written.
*/
- if (to_read || non_overwrite || (to_write && failed) ||
- (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 >= 1 && (sh->dev[failed_num[0]].toread || to_write)) ||
- (failed >= 2 && (sh->dev[failed_num[1]].toread || to_write))
- )
- ) {
- /* we would like to get this block, possibly
- * by computing it, but we might not be able to
- */
- if (uptodate == disks-1) {
- PRINTK("Computing stripe %llu block %d\n",
- (unsigned long long)sh->sector, i);
- compute_block_1(sh, i, 0);
- uptodate++;
- } else if ( uptodate == disks-2 && failed >= 2 ) {
- /* Computing 2-failure is *very* expensive; only do it if failed >= 2 */
- int other;
- for (other=disks; other--;) {
- if ( other == i )
- continue;
- if ( !test_bit(R5_UPTODATE, &sh->dev[other].flags) )
- break;
- }
- BUG_ON(other < 0);
- PRINTK("Computing stripe %llu blocks %d,%d\n",
- (unsigned long long)sh->sector, i, other);
- compute_block_2(sh, i, other);
- uptodate += 2;
- } else if (test_bit(R5_Insync, &dev->flags)) {
- set_bit(R5_LOCKED, &dev->flags);
- set_bit(R5_Wantread, &dev->flags);
- locked++;
- PRINTK("Reading block %d (sync=%d)\n",
- i, syncing);
- }
- }
- }
- set_bit(STRIPE_HANDLE, &sh->state);
- }
+ if (s.to_read || s.non_overwrite || (s.to_write && s.failed) ||
+ (s.syncing && (s.uptodate < disks)) || s.expanding)
+ handle_issuing_new_read_requests6(sh, &s, &r6s, disks);

/* now to consider writing and what else, if anything should be read */
- if (to_write) {
- int rcw=0, must_compute=0;
- for (i=disks ; i--;) {
- dev = &sh->dev[i];
- /* Would I have to read this buffer for reconstruct_write */
- if (!test_bit(R5_OVERWRITE, &dev->flags)
- && i != pd_idx && i != qd_idx
- && (!test_bit(R5_LOCKED, &dev->flags)
- ) &&
- !test_bit(R5_UPTODATE, &dev->flags)) {
- if (test_bit(R5_Insync, &dev->flags)) rcw++;
- else {
- PRINTK("raid6: must_compute: disk %d flags=%#lx\n", i, dev->flags);
- must_compute++;
- }
- }
- }
- PRINTK("for sector %llu, rcw=%d, must_compute=%d\n",
- (unsigned long long)sh->sector, rcw, must_compute);
- set_bit(STRIPE_HANDLE, &sh->state);
-
- if (rcw > 0)
- /* want reconstruct write, but need to get some data */
- for (i=disks; i--;) {
- dev = &sh->dev[i];
- if (!test_bit(R5_OVERWRITE, &dev->flags)
- && !(failed == 0 && (i == pd_idx || i == qd_idx))
- && !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&
- test_bit(R5_Insync, &dev->flags)) {
- if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
- {
- PRINTK("Read_old stripe %llu block %d for Reconstruct\n",
- (unsigned long long)sh->sector, i);
- set_bit(R5_LOCKED, &dev->flags);
- set_bit(R5_Wantread, &dev->flags);
- locked++;
- } else {
- PRINTK("Request delayed stripe %llu block %d for Reconstruct\n",
- (unsigned long long)sh->sector, i);
- set_bit(STRIPE_DELAYED, &sh->state);
- set_bit(STRIPE_HANDLE, &sh->state);
- }
- }
- }
- /* now if nothing is locked, and if we have enough data, we can start a write request */
- if (locked == 0 && rcw == 0 &&
- !test_bit(STRIPE_BIT_DELAY, &sh->state)) {
- if ( must_compute > 0 ) {
- /* We have failed blocks and need to compute them */
- switch ( failed ) {
- case 0: BUG();
- case 1: compute_block_1(sh, failed_num[0], 0); break;
- case 2: compute_block_2(sh, failed_num[0], failed_num[1]); break;
- default: BUG(); /* This request should have been failed? */
- }
- }
-
- PRINTK("Computing parity for stripe %llu\n", (unsigned long long)sh->sector);
- compute_parity6(sh, RECONSTRUCT_WRITE);
- /* now every locked buffer is ready to be written */
- for (i=disks; i--;)
- if (test_bit(R5_LOCKED, &sh->dev[i].flags)) {
- PRINTK("Writing stripe %llu block %d\n",
- (unsigned long long)sh->sector, i);
- locked++;
- set_bit(R5_Wantwrite, &sh->dev[i].flags);
- }
- /* after a RECONSTRUCT_WRITE, the stripe MUST be in-sync */
- set_bit(STRIPE_INSYNC, &sh->state);
-
- if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
- atomic_dec(&conf->preread_active_stripes);
- if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
- md_wakeup_thread(conf->mddev->thread);
- }
- }
- }
+ if (s.to_write)
+ handle_issuing_new_write_requests6(conf, sh, &s, &r6s, disks);

/* maybe we need to check and possibly fix the parity for this stripe
- * Any reads will already have been scheduled, so we just see if enough data
- * is available
+ * Any reads will already have been scheduled, so we just see if enough
+ * data is available
*/
- if (syncing && locked == 0 && !test_bit(STRIPE_INSYNC, &sh->state)) {
- int update_p = 0, update_q = 0;
- struct r5dev *dev;
-
- set_bit(STRIPE_HANDLE, &sh->state);
-
- BUG_ON(failed>2);
- BUG_ON(uptodate < disks);
- /* Want to check and possibly repair P and Q.
- * However there could be one 'failed' device, in which
- * case we can only check one of them, possibly using the
- * other to generate missing data
- */
-
- /* If !tmp_page, we cannot do the calculations,
- * but as we have set STRIPE_HANDLE, we will soon be called
- * by stripe_handle with a tmp_page - just wait until then.
- */
- if (tmp_page) {
- if (failed == q_failed) {
- /* The only possible failed device holds 'Q', so it makes
- * sense to check P (If anything else were failed, we would
- * have used P to recreate it).
- */
- compute_block_1(sh, pd_idx, 1);
- if (!page_is_zero(sh->dev[pd_idx].page)) {
- compute_block_1(sh,pd_idx,0);
- update_p = 1;
- }
- }
- if (!q_failed && failed < 2) {
- /* q is not failed, and we didn't use it to generate
- * anything, so it makes sense to check it
- */
- memcpy(page_address(tmp_page),
- page_address(sh->dev[qd_idx].page),
- STRIPE_SIZE);
- compute_parity6(sh, UPDATE_PARITY);
- if (memcmp(page_address(tmp_page),
- page_address(sh->dev[qd_idx].page),
- STRIPE_SIZE)!= 0) {
- clear_bit(STRIPE_INSYNC, &sh->state);
- update_q = 1;
- }
- }
- if (update_p || update_q) {
- conf->mddev->resync_mismatches += STRIPE_SECTORS;
- if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
- /* don't try to repair!! */
- update_p = update_q = 0;
- }
+ if (s.syncing && s.locked == 0 && !test_bit(STRIPE_INSYNC, &sh->state))
+ handle_parity_checks6(conf, sh, &s, &r6s, tmp_page, disks);

- /* now write out any block on a failed drive,
- * or P or Q if they need it
- */
-
- if (failed == 2) {
- dev = &sh->dev[failed_num[1]];
- locked++;
- set_bit(R5_LOCKED, &dev->flags);
- set_bit(R5_Wantwrite, &dev->flags);
- }
- if (failed >= 1) {
- dev = &sh->dev[failed_num[0]];
- locked++;
- set_bit(R5_LOCKED, &dev->flags);
- set_bit(R5_Wantwrite, &dev->flags);
- }
-
- if (update_p) {
- dev = &sh->dev[pd_idx];
- locked ++;
- set_bit(R5_LOCKED, &dev->flags);
- set_bit(R5_Wantwrite, &dev->flags);
- }
- if (update_q) {
- dev = &sh->dev[qd_idx];
- locked++;
- set_bit(R5_LOCKED, &dev->flags);
- set_bit(R5_Wantwrite, &dev->flags);
- }
- clear_bit(STRIPE_DEGRADED, &sh->state);
-
- set_bit(STRIPE_INSYNC, &sh->state);
- }
- }
-
- if (syncing && locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
+ if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
md_done_sync(conf->mddev, STRIPE_SECTORS,1);
clear_bit(STRIPE_SYNCING, &sh->state);
}
@@ -2339,9 +2343,9 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
/* If the failed drives are just a ReadError, then we might need
* to progress the repair/check process
*/
- if (failed <= 2 && ! conf->mddev->ro)
- for (i=0; i<failed;i++) {
- dev = &sh->dev[failed_num[i]];
+ if (s.failed <= 2 && !conf->mddev->ro)
+ for (i = 0; i < s.failed; i++) {
+ dev = &sh->dev[r6s.failed_num[i]];
if (test_bit(R5_ReadError, &dev->flags)
&& !test_bit(R5_LOCKED, &dev->flags)
&& test_bit(R5_UPTODATE, &dev->flags)
@@ -2358,7 +2362,7 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
}
}

- if (expanded && test_bit(STRIPE_EXPANDING, &sh->state)) {
+ if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state)) {
/* Need to write out all blocks after computing P&Q */
sh->disks = conf->raid_disks;
sh->pd_idx = stripe_to_pdidx(sh->sector, conf,
@@ -2366,69 +2370,19 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
compute_parity6(sh, RECONSTRUCT_WRITE);
for (i = conf->raid_disks ; i-- ; ) {
set_bit(R5_LOCKED, &sh->dev[i].flags);
- locked++;
+ s.locked++;
set_bit(R5_Wantwrite, &sh->dev[i].flags);
}
clear_bit(STRIPE_EXPANDING, &sh->state);
- } else if (expanded) {
+ } else if (s.expanded) {
clear_bit(STRIPE_EXPAND_READY, &sh->state);
atomic_dec(&conf->reshape_stripes);
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 != pd_idx && i != qd_idx) {
- int dd_idx2, pd_idx2, 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 - conf->max_degraded,
- &dd_idx2, &pd_idx2, conf);
- sh2 = get_active_stripe(conf, s,
- conf->raid_disks,
- pd_idx2, 1);
- if (sh2 == NULL)
- /* so for only the early blocks of
- * this stripe have been requests.
- * When later blocks get requests, we
- * will try again
- */
- continue;
- if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
- test_bit(R5_Expanded,
- &sh2->dev[dd_idx2].flags)) {
- /* must have already done this block */
- release_stripe(sh2);
- continue;
- }
- memcpy(page_address(sh2->dev[dd_idx2].page),
- page_address(sh->dev[i].page),
- STRIPE_SIZE);
- set_bit(R5_Expanded, &sh2->dev[dd_idx2].flags);
- set_bit(R5_UPTODATE, &sh2->dev[dd_idx2].flags);
- for (j = 0 ; j < conf->raid_disks ; j++)
- if (j != sh2->pd_idx &&
- j != raid6_next_disk(sh2->pd_idx,
- sh2->disks) &&
- !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);
- }
- }
+ if (s.expanding && s.locked == 0)
+ handle_stripe_expansion(conf, sh, &r6s);

spin_unlock(&sh->lock);

@@ -2470,7 +2424,7 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
rcu_read_unlock();

if (rdev) {
- if (syncing || expanding || expanded)
+ if (s.syncing || s.expanding || s.expanded)
md_sync_acct(rdev->bdev, STRIPE_SECTORS);

bi->bi_bdev = rdev->bdev;
diff --git a/include/linux/raid/raid5.h b/include/linux/raid/raid5.h
index d8286db..208aa68 100644
--- a/include/linux/raid/raid5.h
+++ b/include/linux/raid/raid5.h
@@ -145,6 +145,22 @@ struct stripe_head {
unsigned long flags;
} dev[1]; /* allocated with extra space depending of RAID geometry */
};
+
+/* stripe_head_state - collects and tracks the dynamic state of a stripe_head
+ * for handle_stripe. It is only valid under spin_lock(sh->lock);
+ */
+struct stripe_head_state {
+ int syncing, expanding, expanded;
+ int locked, uptodate, to_read, to_write, failed, written;
+ int non_overwrite, dirty;
+ int failed_num;
+};
+
+/* r6_state - extra state data only relevant to r6 */
+struct r6_state {
+ int p_failed, q_failed, qd_idx, failed_num[2];
+};
+
/* Flags */
#define R5_UPTODATE 0 /* page contains current data */
#define R5_LOCKED 1 /* IO has been submitted on "req" */