Because bios will merge at block-layer,so bios-error may caused by other
bio which be merged into to the same request.
Using this flag,it will find exactly error-sector and not do redundant
operation like re-write and re-read.
V0->V1:Using REQ_FLUSH instead REQ_NOMERGE avoid bio merging at block
layer.
Signed-off-by: Jianpeng Ma <majianpeng@xxxxxxxxx>
---
drivers/md/raid5.c | 14 ++++++++++++--
drivers/md/raid5.h | 1 +
2 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 04348d7..059989f6 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -640,6 +640,9 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
else
bi->bi_sector = (sh->sector
+ rdev->data_offset);
+ if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
+ bi->bi_rw |= REQ_FLUSH;
+
bi->bi_flags = 1 << BIO_UPTODATE;
bi->bi_idx = 0;
bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
@@ -1739,7 +1742,9 @@ static void raid5_end_read_request(struct bio * bi, int error)
atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
clear_bit(R5_ReadError, &sh->dev[i].flags);
clear_bit(R5_ReWrite, &sh->dev[i].flags);
- }
+ } else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
+ clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
+
if (atomic_read(&rdev->read_errors))
atomic_set(&rdev->read_errors, 0);
} else {
@@ -1784,7 +1789,11 @@ static void raid5_end_read_request(struct bio * bi, int error)
else
retry = 1;
if (retry)
- set_bit(R5_ReadError, &sh->dev[i].flags);
+ if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
+ set_bit(R5_ReadError, &sh->dev[i].flags);
+ clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
+ } else
+ set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
else {
clear_bit(R5_ReadError, &sh->dev[i].flags);
clear_bit(R5_ReWrite, &sh->dev[i].flags);
@@ -4504,6 +4513,7 @@ static int retry_aligned_read(struct r5conf *conf, struct bio *raid_bio)
return handled;
}
+ set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
handle_stripe(sh);
release_stripe(sh);
handled++;
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index 2164021..6767d07 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -273,6 +273,7 @@ enum r5dev_flags {
R5_Wantwrite,
R5_Overlap, /* There is a pending overlapping request
* on this block */
+ R5_ReadNoMerge, /* prevent bio from merging in block-layer */
R5_ReadError, /* seen a read error here recently */
R5_ReWrite, /* have tried to over-write the readerror */
--
1.7.5.4
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