md/raid10: avoid reading from known bad blocks - part 2

When redirecting a read error to a different device, we must
again avoid bad blocks and possibly split the request.

Spin_lock typo fixed thanks to Dan Carpenter <error27@gmail.com>

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

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 872bf94..37801d6 100644 (file)
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1746,14 +1746,15 @@ static void handle_read_error(mddev_t *mddev, r10bio_t *r10_bio)
        rdev_dec_pending(conf->mirrors[mirror].rdev, mddev);
 
        bio = r10_bio->devs[slot].bio;
+       bdevname(bio->bi_bdev, b);
        r10_bio->devs[slot].bio =
                mddev->ro ? IO_BLOCKED : NULL;
+read_more:
        mirror = read_balance(conf, r10_bio, &max_sectors);
-       if (mirror == -1 || max_sectors < r10_bio->sectors) {
+       if (mirror == -1) {
                printk(KERN_ALERT "md/raid10:%s: %s: unrecoverable I/O"
                       " read error for block %llu\n",
-                      mdname(mddev),
-                      bdevname(bio->bi_bdev, b),
+                      mdname(mddev), b,
                       (unsigned long long)r10_bio->sector);
                raid_end_bio_io(r10_bio);
                bio_put(bio);
@@ -1761,7 +1762,8 @@ static void handle_read_error(mddev_t *mddev, r10bio_t *r10_bio)
        }
 
        do_sync = (r10_bio->master_bio->bi_rw & REQ_SYNC);
-       bio_put(bio);
+       if (bio)
+               bio_put(bio);
        slot = r10_bio->read_slot;
        rdev = conf->mirrors[mirror].rdev;
        printk_ratelimited(
@@ -1773,6 +1775,9 @@ static void handle_read_error(mddev_t *mddev, r10bio_t *r10_bio)
                (unsigned long long)r10_bio->sector);
        bio = bio_clone_mddev(r10_bio->master_bio,
                              GFP_NOIO, mddev);
+       md_trim_bio(bio,
+                   r10_bio->sector - bio->bi_sector,
+                   max_sectors);
        r10_bio->devs[slot].bio = bio;
        bio->bi_sector = r10_bio->devs[slot].addr
                + rdev->data_offset;
@@ -1780,7 +1785,37 @@ static void handle_read_error(mddev_t *mddev, r10bio_t *r10_bio)
        bio->bi_rw = READ | do_sync;
        bio->bi_private = r10_bio;
        bio->bi_end_io = raid10_end_read_request;
-       generic_make_request(bio);
+       if (max_sectors < r10_bio->sectors) {
+               /* Drat - have to split this up more */
+               struct bio *mbio = r10_bio->master_bio;
+               int sectors_handled =
+                       r10_bio->sector + max_sectors
+                       - mbio->bi_sector;
+               r10_bio->sectors = max_sectors;
+               spin_lock_irq(&conf->device_lock);
+               if (mbio->bi_phys_segments == 0)
+                       mbio->bi_phys_segments = 2;
+               else
+                       mbio->bi_phys_segments++;
+               spin_unlock_irq(&conf->device_lock);
+               generic_make_request(bio);
+               bio = NULL;
+
+               r10_bio = mempool_alloc(conf->r10bio_pool,
+                                       GFP_NOIO);
+               r10_bio->master_bio = mbio;
+               r10_bio->sectors = (mbio->bi_size >> 9)
+                       - sectors_handled;
+               r10_bio->state = 0;
+               set_bit(R10BIO_ReadError,
+                       &r10_bio->state);
+               r10_bio->mddev = mddev;
+               r10_bio->sector = mbio->bi_sector
+                       + sectors_handled;
+
+               goto read_more;
+       } else
+               generic_make_request(bio);
 }
 
 static void raid10d(mddev_t *mddev)