diff options
| -rw-r--r-- | drivers/md/raid5.c | 161 |
1 files changed, 138 insertions, 23 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index d89a25e7c17..d9521aa6946 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -1822,7 +1822,79 @@ static void compute_block_2(struct stripe_head *sh, int dd_idx1, int dd_idx2) } } +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. @@ -2217,27 +2289,8 @@ static void handle_issuing_new_write_requests5(raid5_conf_t *conf, * we can start a write request */ if (s->locked == 0 && (rcw == 0 || rmw == 0) && - !test_bit(STRIPE_BIT_DELAY, &sh->state)) { - pr_debug("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)) { - pr_debug("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); - } - } + !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, @@ -2656,8 +2709,70 @@ static void handle_stripe5(struct stripe_head *sh) (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 (s.to_write) + /* Now we check to see if any write operations have recently + * completed + */ + + /* leave prexor set until postxor is done, allows us to distinguish + * a rmw from a rcw during biodrain + */ + if (test_bit(STRIPE_OP_PREXOR, &sh->ops.complete) && + test_bit(STRIPE_OP_POSTXOR, &sh->ops.complete)) { + + clear_bit(STRIPE_OP_PREXOR, &sh->ops.complete); + clear_bit(STRIPE_OP_PREXOR, &sh->ops.ack); + clear_bit(STRIPE_OP_PREXOR, &sh->ops.pending); + + for (i = disks; i--; ) + clear_bit(R5_Wantprexor, &sh->dev[i].flags); + } + + /* if only POSTXOR is set then this is an 'expand' postxor */ + if (test_bit(STRIPE_OP_BIODRAIN, &sh->ops.complete) && + test_bit(STRIPE_OP_POSTXOR, &sh->ops.complete)) { + + clear_bit(STRIPE_OP_BIODRAIN, &sh->ops.complete); + clear_bit(STRIPE_OP_BIODRAIN, &sh->ops.ack); + clear_bit(STRIPE_OP_BIODRAIN, &sh->ops.pending); + + clear_bit(STRIPE_OP_POSTXOR, &sh->ops.complete); + clear_bit(STRIPE_OP_POSTXOR, &sh->ops.ack); + clear_bit(STRIPE_OP_POSTXOR, &sh->ops.pending); + + /* All the 'written' buffers and the parity block are ready to + * be written back to disk + */ + BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags)); + for (i = disks; i--; ) { + dev = &sh->dev[i]; + if (test_bit(R5_LOCKED, &dev->flags) && + (i == sh->pd_idx || dev->written)) { + pr_debug("Writing block %d\n", i); + set_bit(R5_Wantwrite, &dev->flags); + if (!test_and_set_bit( + STRIPE_OP_IO, &sh->ops.pending)) + sh->ops.count++; + if (!test_bit(R5_Insync, &dev->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); + } + } + + /* Now to consider new write requests and what else, if anything + * should be read. We do not handle new writes when: + * 1/ A 'write' operation (copy+xor) is already in flight. + * 2/ A 'check' operation is in flight, as it may clobber the parity + * block. + */ + if (s.to_write && !test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending) && + !test_bit(STRIPE_OP_CHECK, &sh->ops.pending)) handle_issuing_new_write_requests5(conf, sh, &s, disks); /* maybe we need to check and possibly fix the parity for this stripe |