md/raid10: clear bad-block record when write succeeds.

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 <neilb@suse.de>

2 files changed, 100 insertions, 12 deletions

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 13077a3fd7d2..39b2058845f5 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 c646152ba4e4..d8b7f9af92d5 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