Re: 2.6.23.1: mdadm/raid5 hung/d-state
From: Dan Williams <hidden>
Date: 2007-11-07 01:25:19
Also in:
lkml
Subsystem:
software raid (multiple disks) support, the rest · Maintainers:
Song Liu, Yu Kuai, Linus Torvalds
Possibly related (same subject, not in this thread)
- 2007-11-04 · Re: 2.6.23.1: mdadm/raid5 hung/d-state · David Greaves <hidden>
- 2007-11-04 · Re: 2.6.23.1: mdadm/raid5 hung/d-state · BERTRAND Joël <hidden>
- 2007-11-04 · Re: 2.6.23.1: mdadm/raid5 hung/d-state · Justin Piszcz <hidden>
- 2007-11-04 · Re: 2.6.23.1: mdadm/raid5 hung/d-state · Michael Tokarev <hidden>
- 2007-11-04 · Re: 2.6.23.1: mdadm/raid5 hung/d-state · Justin Piszcz <hidden>
On Tue, 2007-11-06 at 03:19 -0700, BERTRAND Joël wrote:
Done. Here is obtained ouput :
Much appreciated.
[ 1260.969314] handling stripe 7629696, state=0x14 cnt=1, pd_idx=2 ops=0:0:0 [ 1260.980606] check 5: state 0x6 toread 0000000000000000 read 0000000000000000 write fffff800ffcffcc0 written 0000000000000000 [ 1260.994808] check 4: state 0x6 toread 0000000000000000 read 0000000000000000 write fffff800fdd4e360 written 0000000000000000 [ 1261.009325] check 3: state 0x1 toread 0000000000000000 read 0000000000000000 write 0000000000000000 written 0000000000000000 [ 1261.244478] check 2: state 0x1 toread 0000000000000000 read 0000000000000000 write 0000000000000000 written 0000000000000000 [ 1261.270821] check 1: state 0x6 toread 0000000000000000 read 0000000000000000 write fffff800ff517e40 written 0000000000000000 [ 1261.312320] check 0: state 0x6 toread 0000000000000000 read 0000000000000000 write fffff800fd4cae60 written 0000000000000000 [ 1261.361030] locked=4 uptodate=2 to_read=0 to_write=4 failed=0 failed_num=0 [ 1261.443120] for sector 7629696, rmw=0 rcw=0
[..] This looks as if the blocks were prepared to be written out, but were never handled in ops_run_biodrain(), so they remain locked forever. The operations flags are all clear which means handle_stripe thinks nothing else needs to be done. The following patch, also attached, cleans up cases where the code looks at sh->ops.pending when it should be looking at the consistent stack-based snapshot of the operations flags. --- drivers/md/raid5.c | 16 +++++++++------- 1 files changed, 9 insertions(+), 7 deletions(-)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 496b9a3..e1a3942 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c@@ -693,7 +693,8 @@ 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) +ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx, + unsigned long pending) { int disks = sh->disks; int pd_idx = sh->pd_idx, i;
@@ -701,7 +702,7 @@ ops_run_biodrain(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 (Wantprexor) */ - int prexor = test_bit(STRIPE_OP_PREXOR, &sh->ops.pending); + int prexor = test_bit(STRIPE_OP_PREXOR, &pending); pr_debug("%s: stripe %llu\n", __FUNCTION__, (unsigned long long)sh->sector);
@@ -778,7 +779,8 @@ static void ops_complete_write(void *stripe_head_ref) } static void -ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx) +ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx, + unsigned long pending) { /* kernel stack size limits the total number of disks */ int disks = sh->disks;
@@ -786,7 +788,7 @@ 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, &sh->ops.pending); + int prexor = test_bit(STRIPE_OP_PREXOR, &pending); unsigned long flags; dma_async_tx_callback callback;
@@ -813,7 +815,7 @@ 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, &sh->ops.pending) ? + callback = test_bit(STRIPE_OP_BIODRAIN, &pending) ? ops_complete_write : ops_complete_postxor; /* 1/ if we prexor'd then the dest is reused as a source
@@ -901,12 +903,12 @@ static void raid5_run_ops(struct stripe_head *sh, unsigned long pending) tx = ops_run_prexor(sh, tx); if (test_bit(STRIPE_OP_BIODRAIN, &pending)) { - tx = ops_run_biodrain(sh, tx); + tx = ops_run_biodrain(sh, tx, pending); overlap_clear++; } if (test_bit(STRIPE_OP_POSTXOR, &pending)) - ops_run_postxor(sh, tx); + ops_run_postxor(sh, tx, pending); if (test_bit(STRIPE_OP_CHECK, &pending)) ops_run_check(sh);
Attachments
- raid5-fix-unending-write-sequence.patch [text/x-patch] 2650 bytes · preview