[md PATCH 30/36] md/raid10: clear bad-block record when writesucceeds.

If we succeed in writing to a block that was recorded as
being bad, we clear the bad-block record.

This requires some delayed handling as the bad-block-list update has
to happen in process-context.

Signed-off-by: NeilBrown
---

drivers/md/raid10.c | 101 +++++++++++++++++++++++++++++++++++++++++++++------
drivers/md/raid10.h | 11 ++++++
2 files changed, 100 insertions(+), 12 deletions(-)

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 7dcd318..c809d3d 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -181,7 +181,7 @@ static void put_all_bios(conf_t *conf, r10bio_t *r10_bio)

for (i = 0; i < conf->copies; i++) {
struct bio **bio = & r10_bio->devs[i].bio;
- if (*bio && *bio != IO_BLOCKED)
+ if (!BIO_SPECIAL(*bio))
bio_put(*bio);
*bio = NULL;
}
@@ -267,7 +267,8 @@ static inline void update_head_pos(int slot, r10bio_t *r10_bio)
/*
* Find the disk number which triggered given bio
*/
-static int find_bio_disk(conf_t *conf, r10bio_t *r10_bio, struct bio *bio)
+static int find_bio_disk(conf_t *conf, r10bio_t *r10_bio,
+ struct bio *bio, int *slotp)
{
int slot;

@@ -278,6 +279,8 @@ static int find_bio_disk(conf_t *conf, r10bio_t *r10_bio, struct bio *bio)
BUG_ON(slot == conf->copies);
update_head_pos(slot, r10_bio);

+ if (slotp)
+ *slotp = slot;
return r10_bio->devs[slot].devnum;
}

@@ -329,9 +332,11 @@ static void raid10_end_write_request(struct bio *bio, int error)
int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
r10bio_t *r10_bio = bio->bi_private;
int dev;
+ int dec_rdev = 1;
conf_t *conf = r10_bio->mddev->private;
+ int slot;

- dev = find_bio_disk(conf, r10_bio, bio);
+ dev = find_bio_disk(conf, r10_bio, bio, &slot);

/*
* this branch is our 'one mirror IO has finished' event handler:
@@ -340,7 +345,7 @@ static void raid10_end_write_request(struct bio *bio, int error)
md_error(r10_bio->mddev, conf->mirrors[dev].rdev);
/* an I/O failed, we can't clear the bitmap */
set_bit(R10BIO_Degraded, &r10_bio->state);
- } else
+ } else {
/*
* Set R10BIO_Uptodate in our master bio, so that
* we will return a good error code for to the higher
@@ -350,8 +355,23 @@ static void raid10_end_write_request(struct bio *bio, int error)
* user-side. So if something waits for IO, then it will
* wait for the 'master' bio.
*/
+ sector_t first_bad;
+ int bad_sectors;
+
set_bit(R10BIO_Uptodate, &r10_bio->state);

+ /* Maybe we can clear some bad blocks. */
+ if (is_badblock(conf->mirrors[dev].rdev,
+ r10_bio->devs[slot].addr,
+ r10_bio->sectors,
+ &first_bad, &bad_sectors)) {
+ bio_put(bio);
+ r10_bio->devs[slot].bio = IO_MADE_GOOD;
+ dec_rdev = 0;
+ set_bit(R10BIO_MadeGood, &r10_bio->state);
+ }
+ }
+
/*
*
* Let's see if all mirrored write operations have finished
@@ -364,10 +384,13 @@ static void raid10_end_write_request(struct bio *bio, int error)
!test_bit(R10BIO_Degraded, &r10_bio->state),
0);
md_write_end(r10_bio->mddev);
- raid_end_bio_io(r10_bio);
+ if (test_bit(R10BIO_MadeGood, &r10_bio->state))
+ reschedule_retry(r10_bio);
+ else
+ raid_end_bio_io(r10_bio);
}
-
- rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
+ if (dec_rdev)
+ rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
}


@@ -1382,7 +1405,7 @@ static void end_sync_read(struct bio *bio, int error)
conf_t *conf = r10_bio->mddev->private;
int d;

- d = find_bio_disk(conf, r10_bio, bio);
+ d = find_bio_disk(conf, r10_bio, bio, NULL);

if (test_bit(BIO_UPTODATE, &bio->bi_flags))
set_bit(R10BIO_Uptodate, &r10_bio->state);
@@ -1414,23 +1437,37 @@ static void end_sync_write(struct bio *bio, int error)
mddev_t *mddev = r10_bio->mddev;
conf_t *conf = mddev->private;
int d;
+ sector_t first_bad;
+ int bad_sectors;
+ int slot;

- d = find_bio_disk(conf, r10_bio, bio);
+ d = find_bio_disk(conf, r10_bio, bio, &slot);

if (!uptodate)
md_error(mddev, conf->mirrors[d].rdev);
+ else if (is_badblock(conf->mirrors[d].rdev,
+ r10_bio->devs[slot].addr,
+ r10_bio->sectors,
+ &first_bad, &bad_sectors))
+ set_bit(R10BIO_MadeGood, &r10_bio->state);

rdev_dec_pending(conf->mirrors[d].rdev, mddev);
while (atomic_dec_and_test(&r10_bio->remaining)) {
if (r10_bio->master_bio == NULL) {
/* the primary of several recovery bios */
sector_t s = r10_bio->sectors;
- put_buf(r10_bio);
+ if (test_bit(R10BIO_MadeGood, &r10_bio->state))
+ reschedule_retry(r10_bio);
+ else
+ put_buf(r10_bio);
md_done_sync(mddev, s, 1);
break;
} else {
r10bio_t *r10_bio2 = (r10bio_t *)r10_bio->master_bio;
- put_buf(r10_bio);
+ if (test_bit(R10BIO_MadeGood, &r10_bio->state))
+ reschedule_retry(r10_bio);
+ else
+ put_buf(r10_bio);
r10_bio = r10_bio2;
}
}
@@ -1901,6 +1938,44 @@ read_more:
generic_make_request(bio);
}

+static void handle_write_completed(conf_t *conf, r10bio_t *r10_bio)
+{
+ /* Some sort of write request has finished and it
+ * succeeded in writing where we thought there was a
+ * bad block. So forget the bad block.
+ */
+ int m;
+ mdk_rdev_t *rdev;
+
+ if (test_bit(R10BIO_IsSync, &r10_bio->state) ||
+ test_bit(R10BIO_IsRecover, &r10_bio->state)) {
+ for (m = 0; m < conf->copies; m++)
+ if (r10_bio->devs[m].bio &&
+ test_bit(BIO_UPTODATE,
+ &r10_bio->devs[m].bio->bi_flags)) {
+ int dev = r10_bio->devs[m].devnum;
+ rdev = conf->mirrors[dev].rdev;
+ rdev_clear_badblocks(
+ rdev,
+ r10_bio->devs[m].addr,
+ r10_bio->sectors);
+ }
+ put_buf(r10_bio);
+ } else {
+ for (m = 0; m < conf->copies; m++)
+ if (r10_bio->devs[m].bio == IO_MADE_GOOD) {
+ int dev = r10_bio->devs[m].devnum;
+ rdev = conf->mirrors[dev].rdev;
+ rdev_clear_badblocks(
+ rdev,
+ r10_bio->devs[m].addr,
+ r10_bio->sectors);
+ rdev_dec_pending(rdev, conf->mddev);
+ }
+ raid_end_bio_io(r10_bio);
+ }
+}
+
static void raid10d(mddev_t *mddev)
{
r10bio_t *r10_bio;
@@ -1928,7 +2003,9 @@ static void raid10d(mddev_t *mddev)

mddev = r10_bio->mddev;
conf = mddev->private;
- if (test_bit(R10BIO_IsSync, &r10_bio->state))
+ if (test_bit(R10BIO_MadeGood, &r10_bio->state))
+ handle_write_completed(conf, r10_bio);
+ else if (test_bit(R10BIO_IsSync, &r10_bio->state))
sync_request_write(mddev, r10_bio);
else if (test_bit(R10BIO_IsRecover, &r10_bio->state))
recovery_request_write(mddev, r10_bio);
diff --git a/drivers/md/raid10.h b/drivers/md/raid10.h
index c646152..d8b7f9a 100644
--- a/drivers/md/raid10.h
+++ b/drivers/md/raid10.h
@@ -118,6 +118,13 @@ struct r10bio_s {
* level, we store IO_BLOCKED in the appropriate 'bios' pointer
*/
#define IO_BLOCKED ((struct bio*)1)
+/* When we successfully write to a known bad-block, we need to remove the
+ * bad-block marking which must be done from process context. So we record
+ * the success by setting devs[n].bio to IO_MADE_GOOD
+ */
+#define IO_MADE_GOOD ((struct bio *)2)
+
+#define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)

/* bits for r10bio.state */
#define R10BIO_Uptodate 0
@@ -128,4 +135,8 @@ struct r10bio_s {
* so that raid10d knows what to do with them.
*/
#define R10BIO_ReadError 4
+/* If a write for this request means we can clear some
+ * known-bad-block records, we set this flag.
+ */
+#define R10BIO_MadeGood 5
#endif


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