+ set_bit(R5_LOCKED, &sh->dev[i].flags);
+ set_bit(R5_UPTODATE, &sh->dev[i].flags);
+ }
+
+// switch(method) {
+// case RECONSTRUCT_WRITE:
+// case CHECK_PARITY:
+// case UPDATE_PARITY:
+ /* Note that unlike RAID-5, the ordering of the disks matters greatly. */
+ /* FIX: Is this ordering of drives even remotely optimal? */
+ count = 0;
+ i = d0_idx;
+ do {
+ ptrs[count++] = page_address(sh->dev[i].page);
+ if (count <= disks-2 && !test_bit(R5_UPTODATE, &sh->dev[i].flags))
+ printk("block %d/%d not uptodate on parity calc\n", i,count);
+ i = raid6_next_disk(i, disks);
+ } while ( i != d0_idx );
+// break;
+// }
+
+ raid6_call.gen_syndrome(disks, STRIPE_SIZE, ptrs);
+
+ switch(method) {
+ case RECONSTRUCT_WRITE:
+ set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
+ set_bit(R5_UPTODATE, &sh->dev[qd_idx].flags);
+ set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
+ set_bit(R5_LOCKED, &sh->dev[qd_idx].flags);
+ break;
+ case UPDATE_PARITY:
+ set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
+ set_bit(R5_UPTODATE, &sh->dev[qd_idx].flags);
+ break;
+ }
+}
+
+
+/* Compute one missing block */
+static void compute_block_1(struct stripe_head *sh, int dd_idx, int nozero)
+{
+ int i, count, disks = sh->disks;
+ void *ptr[MAX_XOR_BLOCKS], *dest, *p;
+ int pd_idx = sh->pd_idx;
+ int qd_idx = raid6_next_disk(pd_idx, disks);
+
+ pr_debug("compute_block_1, stripe %llu, idx %d\n",
+ (unsigned long long)sh->sector, dd_idx);
+
+ if ( dd_idx == qd_idx ) {
+ /* We're actually computing the Q drive */
+ compute_parity6(sh, UPDATE_PARITY);
+ } else {
+ dest = page_address(sh->dev[dd_idx].page);
+ if (!nozero) memset(dest, 0, STRIPE_SIZE);
+ count = 0;
+ for (i = disks ; i--; ) {
+ if (i == dd_idx || i == qd_idx)
+ continue;
+ p = page_address(sh->dev[i].page);
+ if (test_bit(R5_UPTODATE, &sh->dev[i].flags))
+ ptr[count++] = p;
+ else
+ printk("compute_block() %d, stripe %llu, %d"
+ " not present\n", dd_idx,
+ (unsigned long long)sh->sector, i);
+
+ check_xor();
+ }
+ if (count)
+ xor_blocks(count, STRIPE_SIZE, dest, ptr);
+ if (!nozero) set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
+ else clear_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
+ }
+}
+
+/* Compute two missing blocks */
+static void compute_block_2(struct stripe_head *sh, int dd_idx1, int dd_idx2)
+{
+ int i, count, disks = sh->disks;
+ int pd_idx = sh->pd_idx;
+ int qd_idx = raid6_next_disk(pd_idx, disks);
+ int d0_idx = raid6_next_disk(qd_idx, disks);
+ int faila, failb;
+
+ /* faila and failb are disk numbers relative to d0_idx */
+ /* pd_idx become disks-2 and qd_idx become disks-1 */
+ faila = (dd_idx1 < d0_idx) ? dd_idx1+(disks-d0_idx) : dd_idx1-d0_idx;
+ failb = (dd_idx2 < d0_idx) ? dd_idx2+(disks-d0_idx) : dd_idx2-d0_idx;
+
+ BUG_ON(faila == failb);
+ if ( failb < faila ) { int tmp = faila; faila = failb; failb = tmp; }
+
+ pr_debug("compute_block_2, stripe %llu, idx %d,%d (%d,%d)\n",
+ (unsigned long long)sh->sector, dd_idx1, dd_idx2, faila, failb);
+
+ if ( failb == disks-1 ) {
+ /* Q disk is one of the missing disks */
+ if ( faila == disks-2 ) {
+ /* Missing P+Q, just recompute */
+ compute_parity6(sh, UPDATE_PARITY);
+ return;
+ } else {
+ /* We're missing D+Q; recompute D from P */
+ compute_block_1(sh, (dd_idx1 == qd_idx) ? dd_idx2 : dd_idx1, 0);
+ compute_parity6(sh, UPDATE_PARITY); /* Is this necessary? */
+ return;
+ }
+ }
+
+ /* We're missing D+P or D+D; build pointer table */
+ {
+ /**** FIX THIS: This could be very bad if disks is close to 256 ****/
+ void *ptrs[disks];
+
+ count = 0;
+ i = d0_idx;
+ do {
+ ptrs[count++] = page_address(sh->dev[i].page);
+ i = raid6_next_disk(i, disks);
+ if (i != dd_idx1 && i != dd_idx2 &&
+ !test_bit(R5_UPTODATE, &sh->dev[i].flags))
+ printk("compute_2 with missing block %d/%d\n", count, i);
+ } while ( i != d0_idx );
+
+ if ( failb == disks-2 ) {
+ /* We're missing D+P. */
+ raid6_datap_recov(disks, STRIPE_SIZE, faila, ptrs);
+ } else {
+ /* We're missing D+D. */
+ raid6_2data_recov(disks, STRIPE_SIZE, faila, failb, ptrs);
+ }
+
+ /* Both the above update both missing blocks */
+ set_bit(R5_UPTODATE, &sh->dev[dd_idx1].flags);
+ set_bit(R5_UPTODATE, &sh->dev[dd_idx2].flags);
+ }
+}
+
+static int
+handle_write_operations5(struct stripe_head *sh, int rcw, int expand)
+{
+ int i, pd_idx = sh->pd_idx, disks = sh->disks;
+ int locked = 0;
+
+ if (rcw) {
+ /* if we are not expanding this is a proper write request, and
+ * there will be bios with new data to be drained into the
+ * stripe cache
+ */
+ if (!expand) {
+ set_bit(STRIPE_OP_BIODRAIN, &sh->ops.pending);
+ sh->ops.count++;
+ }
+
+ set_bit(STRIPE_OP_POSTXOR, &sh->ops.pending);
+ sh->ops.count++;
+
+ for (i = disks; i--; ) {
+ struct r5dev *dev = &sh->dev[i];
+
+ if (dev->towrite) {
+ set_bit(R5_LOCKED, &dev->flags);
+ if (!expand)
+ clear_bit(R5_UPTODATE, &dev->flags);
+ locked++;
+ }
+ }
+ } else {
+ BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
+ test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
+
+ set_bit(STRIPE_OP_PREXOR, &sh->ops.pending);
+ set_bit(STRIPE_OP_BIODRAIN, &sh->ops.pending);
+ set_bit(STRIPE_OP_POSTXOR, &sh->ops.pending);
+
+ sh->ops.count += 3;
+
+ for (i = disks; i--; ) {
+ struct r5dev *dev = &sh->dev[i];
+ if (i == pd_idx)
+ continue;
+
+ /* For a read-modify write there may be blocks that are
+ * locked for reading while others are ready to be
+ * written so we distinguish these blocks by the
+ * R5_Wantprexor bit
+ */
+ if (dev->towrite &&
+ (test_bit(R5_UPTODATE, &dev->flags) ||
+ test_bit(R5_Wantcompute, &dev->flags))) {
+ set_bit(R5_Wantprexor, &dev->flags);
+ set_bit(R5_LOCKED, &dev->flags);
+ clear_bit(R5_UPTODATE, &dev->flags);
+ locked++;
+ }
+ }
+ }
+
+ /* keep the parity disk locked while asynchronous operations
+ * are in flight
+ */
+ set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
+ clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
+ locked++;
+
+ pr_debug("%s: stripe %llu locked: %d pending: %lx\n",
+ __FUNCTION__, (unsigned long long)sh->sector,
+ locked, sh->ops.pending);
+
+ return locked;
+}
+
+/*
+ * Each stripe/dev can have one or more bion attached.
+ * toread/towrite point to the first in a chain.
+ * The bi_next chain must be in order.
+ */
+static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite)
+{
+ struct bio **bip;
+ raid5_conf_t *conf = sh->raid_conf;
+ int firstwrite=0;
+
+ pr_debug("adding bh b#%llu to stripe s#%llu\n",
+ (unsigned long long)bi->bi_sector,
+ (unsigned long long)sh->sector);
+
+
+ spin_lock(&sh->lock);
+ spin_lock_irq(&conf->device_lock);
+ if (forwrite) {
+ bip = &sh->dev[dd_idx].towrite;
+ if (*bip == NULL && sh->dev[dd_idx].written == NULL)
+ firstwrite = 1;
+ } else
+ bip = &sh->dev[dd_idx].toread;
+ while (*bip && (*bip)->bi_sector < bi->bi_sector) {
+ if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector)
+ goto overlap;
+ bip = & (*bip)->bi_next;
+ }
+ if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9))
+ goto overlap;
+
+ BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
+ if (*bip)
+ bi->bi_next = *bip;
+ *bip = bi;
+ bi->bi_phys_segments ++;
+ spin_unlock_irq(&conf->device_lock);
+ spin_unlock(&sh->lock);
+
+ pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
+ (unsigned long long)bi->bi_sector,
+ (unsigned long long)sh->sector, dd_idx);
+
+ if (conf->mddev->bitmap && firstwrite) {
+ bitmap_startwrite(conf->mddev->bitmap, sh->sector,
+ STRIPE_SECTORS, 0);
+ sh->bm_seq = conf->seq_flush+1;
+ set_bit(STRIPE_BIT_DELAY, &sh->state);
+ }
+
+ if (forwrite) {
+ /* check if page is covered */
+ sector_t sector = sh->dev[dd_idx].sector;
+ for (bi=sh->dev[dd_idx].towrite;
+ sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
+ bi && bi->bi_sector <= sector;
+ bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
+ if (bi->bi_sector + (bi->bi_size>>9) >= sector)
+ sector = bi->bi_sector + (bi->bi_size>>9);
+ }
+ if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
+ set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
+ }
+ return 1;
+
+ overlap:
+ set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
+ spin_unlock_irq(&conf->device_lock);
+ spin_unlock(&sh->lock);
+ return 0;
+}
+
+static void end_reshape(raid5_conf_t *conf);
+
+static int page_is_zero(struct page *p)
+{
+ char *a = page_address(p);
+ return ((*(u32*)a) == 0 &&
+ memcmp(a, a+4, STRIPE_SIZE-4)==0);
+}
+
+static int stripe_to_pdidx(sector_t stripe, raid5_conf_t *conf, int disks)
+{
+ int sectors_per_chunk = conf->chunk_size >> 9;
+ int pd_idx, dd_idx;
+ int chunk_offset = sector_div(stripe, sectors_per_chunk);
+
+ raid5_compute_sector(stripe * (disks - conf->max_degraded)
+ *sectors_per_chunk + chunk_offset,
+ disks, disks - conf->max_degraded,
+ &dd_idx, &pd_idx, conf);
+ 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 and
+ * the data has not reached the cache yet.
+ */
+ if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
+ (!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);
+ }
+
+}
+
+/* __handle_issuing_new_read_requests5 - returns 0 if there are no more disks
+ * to process
+ */
+static int __handle_issuing_new_read_requests5(struct stripe_head *sh,
+ struct stripe_head_state *s, int disk_idx, int disks)
+{
+ struct r5dev *dev = &sh->dev[disk_idx];
+ struct r5dev *failed_dev = &sh->dev[s->failed_num];
+
+ /* don't schedule compute operations or reads on the parity block while
+ * a check is in flight
+ */
+ if ((disk_idx == sh->pd_idx) &&
+ test_bit(STRIPE_OP_CHECK, &sh->ops.pending))
+ return ~0;
+
+ /* is the data in this block needed, and can we get it? */
+ 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 &&
+ (failed_dev->toread || (failed_dev->towrite &&
+ !test_bit(R5_OVERWRITE, &failed_dev->flags)
+ ))))) {
+ /* 1/ We would like to get this block, possibly by computing it,
+ * but we might not be able to.
+ *
+ * 2/ Since parity check operations potentially make the parity
+ * block !uptodate it will need to be refreshed before any
+ * compute operations on data disks are scheduled.
+ *
+ * 3/ We hold off parity block re-reads until check operations
+ * have quiesced.
+ */
+ if ((s->uptodate == disks - 1) &&
+ !test_bit(STRIPE_OP_CHECK, &sh->ops.pending)) {
+ set_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending);
+ set_bit(R5_Wantcompute, &dev->flags);
+ sh->ops.target = disk_idx;
+ s->req_compute = 1;
+ sh->ops.count++;
+ /* Careful: from this point on 'uptodate' is in the eye
+ * of raid5_run_ops which services 'compute' operations
+ * before writes. R5_Wantcompute flags a block that will
+ * be R5_UPTODATE by the time it is needed for a
+ * subsequent operation.
+ */
+ s->uptodate++;
+ return 0; /* uptodate + compute == disks */
+ } else if ((s->uptodate < disks - 1) &&
+ test_bit(R5_Insync, &dev->flags)) {
+ /* Note: we hold off compute operations while checks are
+ * in flight, but we still prefer 'compute' over 'read'
+ * hence we only read if (uptodate < * disks-1)
+ */
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantread, &dev->flags);
+ if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
+ sh->ops.count++;
+ s->locked++;
+ pr_debug("Reading block %d (sync=%d)\n", disk_idx,
+ s->syncing);
+ }
+ }
+
+ return ~0;
+}
+
+static void handle_issuing_new_read_requests5(struct stripe_head *sh,
+ struct stripe_head_state *s, int disks)
+{
+ int i;
+
+ /* Clear completed compute operations. Parity recovery
+ * (STRIPE_OP_MOD_REPAIR_PD) implies a write-back which is handled
+ * later on in this routine
+ */
+ if (test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete) &&
+ !test_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending)) {
+ clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete);
+ clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.ack);
+ clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending);
+ }
+
+ /* look for blocks to read/compute, skip this if a compute
+ * is already in flight, or if the stripe contents are in the
+ * midst of changing due to a write
+ */
+ if (!test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending) &&
+ !test_bit(STRIPE_OP_PREXOR, &sh->ops.pending) &&
+ !test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
+ for (i = disks; i--; )
+ if (__handle_issuing_new_read_requests5(
+ sh, s, i, disks) == 0)
+ break;
+ }
+ 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) {
+ pr_debug("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);
+ pr_debug("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++;
+ pr_debug("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;
+ pr_debug("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) ||
+ test_bit(R5_Wantcompute, &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) ||
+ test_bit(R5_Wantcompute, &dev->flags))) {
+ if (test_bit(R5_Insync, &dev->flags)) rcw++;
+ else
+ rcw += 2*disks;
+ }
+ }
+ pr_debug("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_Wantcompute, &dev->flags)) &&
+ test_bit(R5_Insync, &dev->flags)) {
+ if (
+ test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
+ pr_debug("Read_old block "
+ "%d for r-m-w\n", i);
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantread, &dev->flags);
+ if (!test_and_set_bit(
+ STRIPE_OP_IO, &sh->ops.pending))
+ sh->ops.count++;
+ 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_Wantcompute, &dev->flags)) &&
+ test_bit(R5_Insync, &dev->flags)) {
+ if (
+ test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
+ pr_debug("Read_old block "
+ "%d for Reconstruct\n", i);
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantread, &dev->flags);
+ if (!test_and_set_bit(
+ STRIPE_OP_IO, &sh->ops.pending))
+ sh->ops.count++;
+ 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
+ */
+ /* since handle_stripe can be called at any time we need to handle the
+ * case where a compute block operation has been submitted and then a
+ * subsequent call wants to start a write request. raid5_run_ops only
+ * handles the case where compute block and postxor are requested
+ * simultaneously. If this is not the case then new writes need to be
+ * held off until the compute completes.
+ */
+ if ((s->req_compute ||
+ !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending)) &&
+ (s->locked == 0 && (rcw == 0 || rmw == 0) &&
+ !test_bit(STRIPE_BIT_DELAY, &sh->state)))
+ s->locked += handle_write_operations5(sh, rcw == 0, 0);
+}
+
+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 {
+ pr_debug("raid6: must_compute: "
+ "disk %d flags=%#lx\n", i, dev->flags);
+ must_compute++;
+ }