md/raid10: Split handle_read_error out from raid10d.

raid10d() is too big and is about to get bigger, so split
handle_read_error() out as a separate function.

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

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index c489b5c..f1b749c 100644 (file)
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1618,21 +1618,81 @@ static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio)
        }
 }
 
+static void handle_read_error(mddev_t *mddev, r10bio_t *r10_bio)
+{
+       int slot = r10_bio->read_slot;
+       int mirror = r10_bio->devs[slot].devnum;
+       struct bio *bio;
+       conf_t *conf = mddev->private;
+       mdk_rdev_t *rdev;
+       char b[BDEVNAME_SIZE];
+       unsigned long do_sync;
+
+       /* we got a read error. Maybe the drive is bad.  Maybe just
+        * the block and we can fix it.
+        * We freeze all other IO, and try reading the block from
+        * other devices.  When we find one, we re-write
+        * and check it that fixes the read error.
+        * This is all done synchronously while the array is
+        * frozen.
+        */
+       if (mddev->ro == 0) {
+               freeze_array(conf);
+               fix_read_error(conf, mddev, r10_bio);
+               unfreeze_array(conf);
+       }
+       rdev_dec_pending(conf->mirrors[mirror].rdev, mddev);
+
+       bio = r10_bio->devs[slot].bio;
+       r10_bio->devs[slot].bio =
+               mddev->ro ? IO_BLOCKED : NULL;
+       mirror = read_balance(conf, r10_bio);
+       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),
+                      (unsigned long long)r10_bio->sector);
+               raid_end_bio_io(r10_bio);
+               bio_put(bio);
+               return;
+       }
+
+       do_sync = (r10_bio->master_bio->bi_rw & REQ_SYNC);
+       bio_put(bio);
+       slot = r10_bio->read_slot;
+       rdev = conf->mirrors[mirror].rdev;
+       printk_ratelimited(
+               KERN_ERR
+               "md/raid10:%s: %s: redirecting"
+               "sector %llu to another mirror\n",
+               mdname(mddev),
+               bdevname(rdev->bdev, b),
+               (unsigned long long)r10_bio->sector);
+       bio = bio_clone_mddev(r10_bio->master_bio,
+                             GFP_NOIO, mddev);
+       r10_bio->devs[slot].bio = bio;
+       bio->bi_sector = r10_bio->devs[slot].addr
+               + rdev->data_offset;
+       bio->bi_bdev = rdev->bdev;
+       bio->bi_rw = READ | do_sync;
+       bio->bi_private = r10_bio;
+       bio->bi_end_io = raid10_end_read_request;
+       generic_make_request(bio);
+}
+
 static void raid10d(mddev_t *mddev)
 {
        r10bio_t *r10_bio;
-       struct bio *bio;
        unsigned long flags;
        conf_t *conf = mddev->private;
        struct list_head *head = &conf->retry_list;
-       mdk_rdev_t *rdev;
        struct blk_plug plug;
 
        md_check_recovery(mddev);
 
        blk_start_plug(&plug);
        for (;;) {
-               char b[BDEVNAME_SIZE];
 
                flush_pending_writes(conf);
 
@@ -1652,60 +1712,9 @@ static void raid10d(mddev_t *mddev)
                        sync_request_write(mddev, r10_bio);
                else if (test_bit(R10BIO_IsRecover, &r10_bio->state))
                        recovery_request_write(mddev, r10_bio);
-               else {
-                       int slot = r10_bio->read_slot;
-                       int mirror = r10_bio->devs[slot].devnum;
-                       /* we got a read error. Maybe the drive is bad.  Maybe just
-                        * the block and we can fix it.
-                        * We freeze all other IO, and try reading the block from
-                        * other devices.  When we find one, we re-write
-                        * and check it that fixes the read error.
-                        * This is all done synchronously while the array is
-                        * frozen.
-                        */
-                       if (mddev->ro == 0) {
-                               freeze_array(conf);
-                               fix_read_error(conf, mddev, r10_bio);
-                               unfreeze_array(conf);
-                       }
-                       rdev_dec_pending(conf->mirrors[mirror].rdev, mddev);
-
-                       bio = r10_bio->devs[slot].bio;
-                       r10_bio->devs[slot].bio =
-                               mddev->ro ? IO_BLOCKED : NULL;
-                       mirror = read_balance(conf, r10_bio);
-                       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),
-                                      (unsigned long long)r10_bio->sector);
-                               raid_end_bio_io(r10_bio);
-                               bio_put(bio);
-                       } else {
-                               const unsigned long do_sync = (r10_bio->master_bio->bi_rw & REQ_SYNC);
-                               bio_put(bio);
-                               slot = r10_bio->read_slot;
-                               rdev = conf->mirrors[mirror].rdev;
-                               printk_ratelimited(
-                                       KERN_ERR
-                                       "md/raid10:%s: %s: redirecting"
-                                       "sector %llu to another mirror\n",
-                                       mdname(mddev),
-                                       bdevname(rdev->bdev, b),
-                                       (unsigned long long)r10_bio->sector);
-                               bio = bio_clone_mddev(r10_bio->master_bio,
-                                                     GFP_NOIO, mddev);
-                               r10_bio->devs[slot].bio = bio;
-                               bio->bi_sector = r10_bio->devs[slot].addr
-                                       + rdev->data_offset;
-                               bio->bi_bdev = rdev->bdev;
-                               bio->bi_rw = READ | do_sync;
-                               bio->bi_private = r10_bio;
-                               bio->bi_end_io = raid10_end_read_request;
-                               generic_make_request(bio);
-                       }
-               }
+               else
+                       handle_read_error(mddev, r10_bio);
+
                cond_resched();
                if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
                        md_check_recovery(mddev);