[PATCH v3 7/8] md/raid10: skip futile retries on P2PDMA mapping failures
Mykola Marzhan
mykola at meshstor.io
Tue Jul 21 10:45:01 PDT 2026
Same handling as the preceding raid1 commit: flag P2PDMA master
bios with R10BIO_P2PDMA at submission; on a BLK_STS_TARGET leg
failure retry writes once as a whole range, don't set
WantReplacement, block the leg for reads without charging the
read-error budget, don't trip FailFast.
Replacement legs keep the stock fail-on-write-error policy:
badblocks are never recorded on a replacement, so failing it is
the only outcome that cannot leave a silent hole in a rebuild.
Fixes: 02666132403a ("md: propagate BLK_FEAT_PCI_P2PDMA from member devices to RAID device")
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Mykola Marzhan <mykola at meshstor.io>
---
drivers/md/raid10.c | 63 ++++++++++++++++++++++++++++++++++-----------
drivers/md/raid10.h | 2 ++
2 files changed, 50 insertions(+), 15 deletions(-)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index f7ef903a3d4e..4c3da50250a5 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -482,15 +482,23 @@ static void raid10_end_write_request(struct bio *bio)
*/
md_error(rdev->mddev, rdev);
else {
- set_bit(WriteErrorSeen, &rdev->flags);
- if (!test_and_set_bit(WantReplacement, &rdev->flags))
- set_bit(MD_RECOVERY_NEEDED,
- &rdev->mddev->recovery);
+ /* Peer/member pairing failure, not member health. */
+ bool p2pdma_unmappable =
+ bio->bi_status == BLK_STS_TARGET &&
+ test_bit(R10BIO_P2PDMA, &r10_bio->state);
+ set_bit(WriteErrorSeen, &rdev->flags);
dec_rdev = 0;
- if (test_bit(FailFast, &rdev->flags) &&
- (bio->bi_opf & MD_FAILFAST)) {
- md_error(rdev->mddev, rdev);
+ if (!p2pdma_unmappable) {
+ if (!test_and_set_bit(WantReplacement,
+ &rdev->flags))
+ set_bit(MD_RECOVERY_NEEDED,
+ &rdev->mddev->recovery);
+
+ if (test_bit(FailFast, &rdev->flags) &&
+ (bio->bi_opf & MD_FAILFAST)) {
+ md_error(rdev->mddev, rdev);
+ }
}
/*
@@ -1170,6 +1178,9 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
*/
gfp_t gfp = err_path ? (GFP_NOIO | __GFP_HIGH) : GFP_NOIO;
+ if (md_bio_is_p2pdma(bio))
+ set_bit(R10BIO_P2PDMA, &r10_bio->state);
+
if (slot >= 0 && r10_bio->devs[slot].rdev) {
/*
* This is an error retry, but we cannot
@@ -1357,6 +1368,9 @@ static bool raid10_write_request(struct mddev *mddev, struct bio *bio,
sector_t sectors;
int max_sectors;
+ if (md_bio_is_p2pdma(bio))
+ set_bit(R10BIO_P2PDMA, &r10_bio->state);
+
if ((mddev_is_clustered(mddev) &&
mddev->cluster_ops->area_resyncing(mddev, WRITE,
bio->bi_iter.bi_sector,
@@ -2786,7 +2800,7 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
}
}
-static void narrow_write_error(struct r10bio *r10_bio, int i)
+static void narrow_write_error(struct r10bio *r10_bio, int i, bool coarse)
{
struct bio *bio = r10_bio->master_bio;
struct mddev *mddev = r10_bio->mddev;
@@ -2800,6 +2814,9 @@ static void narrow_write_error(struct r10bio *r10_bio, int i)
* It is conceivable that the bio doesn't exactly align with
* blocks. We must handle this.
*
+ * With 'coarse', retry the whole range as one bio: P2PDMA
+ * mapping failures fail every block identically.
+ *
* We currently own a reference to the rdev.
*/
@@ -2814,9 +2831,12 @@ static void narrow_write_error(struct r10bio *r10_bio, int i)
block_sectors = roundup(1 << rdev->badblocks.shift, lbs);
sector = r10_bio->sector;
- sectors = ((r10_bio->sector + block_sectors)
- & ~(sector_t)(block_sectors - 1))
- - sector;
+ if (coarse)
+ sectors = sect_to_write;
+ else
+ sectors = ((r10_bio->sector + block_sectors)
+ & ~(sector_t)(block_sectors - 1))
+ - sector;
while (sect_to_write) {
struct bio *wbio;
@@ -2856,6 +2876,7 @@ static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
{
int slot = r10_bio->read_slot;
struct bio *bio;
+ bool p2pdma_error;
struct r10conf *conf = mddev->private;
struct md_rdev *rdev = r10_bio->devs[slot].rdev;
@@ -2868,17 +2889,24 @@ static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
* frozen.
*/
bio = r10_bio->devs[slot].bio;
+ /* evaluate before the bio_put() below */
+ p2pdma_error = bio->bi_status == BLK_STS_TARGET &&
+ test_bit(R10BIO_P2PDMA, &r10_bio->state);
bio_put(bio);
r10_bio->devs[slot].bio = NULL;
if (mddev->ro)
r10_bio->devs[slot].bio = IO_BLOCKED;
- else if (!test_bit(FailFast, &rdev->flags)) {
+ else if (p2pdma_error) {
+ /* Peer can't reach this member: just redirect the read. */
+ r10_bio->devs[slot].bio = IO_BLOCKED;
+ } else if (test_bit(FailFast, &rdev->flags)) {
+ md_error(mddev, rdev);
+ } else {
freeze_array(conf, 1);
fix_read_error(conf, mddev, r10_bio);
unfreeze_array(conf);
- } else
- md_error(mddev, rdev);
+ }
rdev_dec_pending(rdev, mddev);
r10_bio->state = 0;
@@ -2947,8 +2975,13 @@ static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
r10_bio->sectors, 0);
rdev_dec_pending(rdev, conf->mddev);
} else if (bio != NULL && bio->bi_status) {
+ bool coarse = bio->bi_status ==
+ BLK_STS_TARGET &&
+ test_bit(R10BIO_P2PDMA,
+ &r10_bio->state);
+
fail = true;
- narrow_write_error(r10_bio, m);
+ narrow_write_error(r10_bio, m, coarse);
rdev_dec_pending(rdev, conf->mddev);
}
bio = r10_bio->devs[m].repl_bio;
diff --git a/drivers/md/raid10.h b/drivers/md/raid10.h
index ec79d87fb92f..a2e1554f77db 100644
--- a/drivers/md/raid10.h
+++ b/drivers/md/raid10.h
@@ -174,6 +174,8 @@ enum r10bio_state {
R10BIO_Previous,
/* failfast devices did receive failfast requests. */
R10BIO_FailFast,
+/* the master bio carries PCI P2PDMA (peer device memory) pages */
+ R10BIO_P2PDMA,
R10BIO_Discard,
};
#endif
--
2.52.0
More information about the Linux-nvme
mailing list