From d8ee0728b5b30d7a6f62c399a95e953616d31f23 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Sat, 28 Jun 2008 08:32:06 +1000 Subject: [PATCH] md: replace R5_WantPrexor with R5_WantDrain, add 'prexor' reconstruct_states From: Dan Williams Currently ops_run_biodrain and other locations have extra logic to determine which blocks are processed in the prexor and non-prexor cases. This can be eliminated if handle_write_operations5 flags the blocks to be processed in all cases via R5_Wantdrain. The presence of the prexor operation is tracked in sh->reconstruct_state. Signed-off-by: Dan Williams Signed-off-by: Neil Brown --- drivers/md/raid5.c | 89 +++++++++++++++------------------------------- include/linux/raid/raid5.h | 6 ++-- 2 files changed, 32 insertions(+), 63 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index b915936..c712460 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -637,7 +637,7 @@ ops_run_prexor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx) for (i = disks; i--; ) { struct r5dev *dev = &sh->dev[i]; /* Only process blocks that are known to be uptodate */ - if (dev->towrite && test_bit(R5_Wantprexor, &dev->flags)) + if (test_bit(R5_Wantdrain, &dev->flags)) xor_srcs[count++] = dev->page; } @@ -649,16 +649,10 @@ ops_run_prexor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx) } static struct dma_async_tx_descriptor * -ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx, - unsigned long ops_request) +ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx) { int disks = sh->disks; - int pd_idx = sh->pd_idx, i; - - /* check if prexor is active which means only process blocks - * that are part of a read-modify-write (Wantprexor) - */ - int prexor = test_bit(STRIPE_OP_PREXOR, &ops_request); + int i; pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector); @@ -666,20 +660,8 @@ ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx, for (i = disks; i--; ) { struct r5dev *dev = &sh->dev[i]; struct bio *chosen; - int towrite; - towrite = 0; - if (prexor) { /* rmw */ - if (dev->towrite && - test_bit(R5_Wantprexor, &dev->flags)) - towrite = 1; - } else { /* rcw */ - if (i != pd_idx && dev->towrite && - test_bit(R5_LOCKED, &dev->flags)) - towrite = 1; - } - - if (towrite) { + if (test_and_clear_bit(R5_Wantdrain, &dev->flags)) { struct bio *wbi; spin_lock(&sh->lock); @@ -704,18 +686,6 @@ ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx, static void ops_complete_postxor(void *stripe_head_ref) { struct stripe_head *sh = stripe_head_ref; - - pr_debug("%s: stripe %llu\n", __func__, - (unsigned long long)sh->sector); - - sh->reconstruct_state = reconstruct_state_result; - set_bit(STRIPE_HANDLE, &sh->state); - release_stripe(sh); -} - -static void ops_complete_write(void *stripe_head_ref) -{ - struct stripe_head *sh = stripe_head_ref; int disks = sh->disks, i, pd_idx = sh->pd_idx; pr_debug("%s: stripe %llu\n", __func__, @@ -727,14 +697,21 @@ static void ops_complete_write(void *stripe_head_ref) set_bit(R5_UPTODATE, &dev->flags); } - sh->reconstruct_state = reconstruct_state_drain_result; + if (sh->reconstruct_state == reconstruct_state_drain_run) + sh->reconstruct_state = reconstruct_state_drain_result; + else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) + sh->reconstruct_state = reconstruct_state_prexor_drain_result; + else { + BUG_ON(sh->reconstruct_state != reconstruct_state_run); + sh->reconstruct_state = reconstruct_state_result; + } + set_bit(STRIPE_HANDLE, &sh->state); release_stripe(sh); } static void -ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx, - unsigned long ops_request) +ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx) { /* kernel stack size limits the total number of disks */ int disks = sh->disks; @@ -742,9 +719,8 @@ ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx, int count = 0, pd_idx = sh->pd_idx, i; struct page *xor_dest; - int prexor = test_bit(STRIPE_OP_PREXOR, &ops_request); + int prexor = 0; unsigned long flags; - dma_async_tx_callback callback; pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector); @@ -752,7 +728,8 @@ ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx, /* check if prexor is active which means only process blocks * that are part of a read-modify-write (written) */ - if (prexor) { + if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) { + prexor = 1; xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page; for (i = disks; i--; ) { struct r5dev *dev = &sh->dev[i]; @@ -768,10 +745,6 @@ ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx, } } - /* check whether this postxor is part of a write */ - callback = test_bit(STRIPE_OP_BIODRAIN, &ops_request) ? - ops_complete_write : ops_complete_postxor; - /* 1/ if we prexor'd then the dest is reused as a source * 2/ if we did not prexor then we are redoing the parity * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST @@ -785,10 +758,10 @@ ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx, if (unlikely(count == 1)) { flags &= ~(ASYNC_TX_XOR_DROP_DST | ASYNC_TX_XOR_ZERO_DST); tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, - flags, tx, callback, sh); + flags, tx, ops_complete_postxor, sh); } else tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, - flags, tx, callback, sh); + flags, tx, ops_complete_postxor, sh); } static void ops_complete_check(void *stripe_head_ref) @@ -847,12 +820,12 @@ static void raid5_run_ops(struct stripe_head *sh, unsigned long ops_request) tx = ops_run_prexor(sh, tx); if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) { - tx = ops_run_biodrain(sh, tx, ops_request); + tx = ops_run_biodrain(sh, tx); overlap_clear++; } if (test_bit(STRIPE_OP_POSTXOR, &ops_request)) - ops_run_postxor(sh, tx, ops_request); + ops_run_postxor(sh, tx); if (test_bit(STRIPE_OP_CHECK, &ops_request)) ops_run_check(sh); @@ -1669,6 +1642,7 @@ handle_write_operations5(struct stripe_head *sh, struct stripe_head_state *s, if (dev->towrite) { set_bit(R5_LOCKED, &dev->flags); + set_bit(R5_Wantdrain, &dev->flags); if (!expand) clear_bit(R5_UPTODATE, &dev->flags); s->locked++; @@ -1681,7 +1655,7 @@ handle_write_operations5(struct stripe_head *sh, struct stripe_head_state *s, BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) || test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags))); - sh->reconstruct_state = reconstruct_state_drain_run; + sh->reconstruct_state = reconstruct_state_prexor_drain_run; set_bit(STRIPE_OP_PREXOR, &s->ops_request); set_bit(STRIPE_OP_BIODRAIN, &s->ops_request); set_bit(STRIPE_OP_POSTXOR, &s->ops_request); @@ -1691,15 +1665,10 @@ handle_write_operations5(struct stripe_head *sh, struct stripe_head_state *s, 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); + test_bit(R5_Wantcompute, &dev->flags))) { + set_bit(R5_Wantdrain, &dev->flags); set_bit(R5_LOCKED, &dev->flags); clear_bit(R5_UPTODATE, &dev->flags); s->locked++; @@ -2660,11 +2629,11 @@ static void handle_stripe5(struct stripe_head *sh) * completed */ prexor = 0; - if (sh->reconstruct_state == reconstruct_state_drain_result) { + if (sh->reconstruct_state == reconstruct_state_prexor_drain_result) + prexor = 1; + if (sh->reconstruct_state == reconstruct_state_drain_result || + sh->reconstruct_state == reconstruct_state_prexor_drain_result) { sh->reconstruct_state = reconstruct_state_idle; - for (i = disks; i--; ) - prexor += test_and_clear_bit(R5_Wantprexor, - &sh->dev[i].flags); /* All the 'written' buffers and the parity block are ready to * be written back to disk diff --git a/include/linux/raid/raid5.h b/include/linux/raid/raid5.h index 5f3e674..3b26727 100644 --- a/include/linux/raid/raid5.h +++ b/include/linux/raid/raid5.h @@ -187,8 +187,10 @@ enum check_states { */ enum reconstruct_states { reconstruct_state_idle = 0, + reconstruct_state_prexor_drain_run, /* prexor-write */ reconstruct_state_drain_run, /* write */ reconstruct_state_run, /* expand */ + reconstruct_state_prexor_drain_result, reconstruct_state_drain_result, reconstruct_state_result, }; @@ -258,9 +260,7 @@ struct r6_state { #define R5_Wantfill 12 /* dev->toread contains a bio that needs * filling */ -#define R5_Wantprexor 13 /* distinguish blocks ready for rmw from - * other "towrites" - */ +#define R5_Wantdrain 13 /* dev->towrite needs to be drained */ /* * Write method */ -- 2.7.4