md/raid5: write errors should be recorded as bad blocks if possible.

When a write error is detected, don't mark the device as failed
immediately but rather record the fact for handle_stripe to deal with.

Handle_stripe then attempts to record a bad block.  Only if that fails
does the device get marked as faulty.

Signed-off-by: NeilBrown <neilb@suse.de>

2 files changed, 41 insertions, 10 deletions

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 5fc621673e6..9768a7d6714 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1658,8 +1658,10 @@ static void raid5_end_write_request(struct bio *bi, int error)
                 return;
         }
 
-        if (!uptodate)
-                md_error(conf->mddev, conf->disks[i].rdev);
+        if (!uptodate) {
+                set_bit(WriteErrorSeen, &conf->disks[i].rdev->flags);
+                set_bit(R5_WriteError, &sh->dev[i].flags);
+        }
 
         rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
         
@@ -3038,6 +3040,14 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
                         if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
                                 set_bit(R5_Insync, &dev->flags);
                 }
+                if (test_bit(R5_WriteError, &dev->flags)) {
+                        clear_bit(R5_Insync, &dev->flags);
+                        if (!test_bit(Faulty, &rdev->flags)) {
+                                s->handle_bad_blocks = 1;
+                                atomic_inc(&rdev->nr_pending);
+                        } else
+                                clear_bit(R5_WriteError, &dev->flags);
+                }
                 if (!test_bit(R5_Insync, &dev->flags)) {
                         /* The ReadError flag will just be confusing now */
                         clear_bit(R5_ReadError, &dev->flags);
@@ -3086,6 +3096,11 @@ static void handle_stripe(struct stripe_head *sh)
 
         analyse_stripe(sh, &s);
 
+        if (s.handle_bad_blocks) {
+                set_bit(STRIPE_HANDLE, &sh->state);
+                goto finish;
+        }
+
         if (unlikely(s.blocked_rdev)) {
                 if (s.syncing || s.expanding || s.expanded ||
                     s.to_write || s.written) {
@@ -3283,6 +3298,20 @@ finish:
         if (unlikely(s.blocked_rdev))
                 md_wait_for_blocked_rdev(s.blocked_rdev, conf->mddev);
 
+        if (s.handle_bad_blocks)
+                for (i = disks; i--; ) {
+                        mdk_rdev_t *rdev;
+                        struct r5dev *dev = &sh->dev[i];
+                        if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
+                                /* We own a safe reference to the rdev */
+                                rdev = conf->disks[i].rdev;
+                                if (!rdev_set_badblocks(rdev, sh->sector,
+                                                        STRIPE_SECTORS, 0))
+                                        md_error(conf->mddev, rdev);
+                                rdev_dec_pending(rdev, conf->mddev);
+                        }
+                }
+
         if (s.ops_request)
                 raid_run_ops(sh, s.ops_request);
 
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index c5429d12363..8620cb67ae3 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -249,6 +249,7 @@ struct stripe_head_state {
 
         struct bio *return_bi;
         mdk_rdev_t *blocked_rdev;
+        int handle_bad_blocks;
 };
 
 /* Flags */
@@ -264,14 +265,15 @@ struct stripe_head_state {
 #define R5_ReWrite      9       /* have tried to over-write the readerror */
 
 #define R5_Expanded     10      /* This block now has post-expand data */
-#define R5_Wantcompute  11 /* compute_block in progress treat as
-                                    * uptodate
-                                    */
-#define R5_Wantfill     12 /* dev->toread contains a bio that needs
-                                    * filling
-                                    */
-#define R5_Wantdrain    13 /* dev->towrite needs to be drained */
-#define R5_WantFUA      14      /* Write should be FUA */
+#define R5_Wantcompute  11      /* compute_block in progress treat as
+                                 * uptodate
+                                 */
+#define R5_Wantfill     12      /* dev->toread contains a bio that needs
+                                 * filling
+                                 */
+#define R5_Wantdrain    13      /* dev->towrite needs to be drained */
+#define R5_WantFUA      14      /* Write should be FUA */
+#define R5_WriteError   15      /* got a write error - need to record it */
 /*
  * Write method
  */