Add new parameter to 'sync_page_io'.
The new parameter allows us to distinguish between metadata and data
operations.  This becomes important later when we add the ability to
use separate devices for data and metadata.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
                    || test_bit(Faulty, &rdev->flags))
                        continue;
 
-               target = rdev->sb_start + offset + index * (PAGE_SIZE/512);
+               target = offset + index * (PAGE_SIZE/512);
 
                if (sync_page_io(rdev, target,
                                 roundup(size, bdev_logical_block_size(rdev->bdev)),
-                                page, READ)) {
+                                page, READ, true)) {
                        page->index = index;
                        attach_page_buffers(page, NULL); /* so that free_buffer will
                                                          * quietly no-op */
 
 }
 
 int sync_page_io(mdk_rdev_t *rdev, sector_t sector, int size,
-                struct page *page, int rw)
+                struct page *page, int rw, bool metadata_op)
 {
        struct bio *bio = bio_alloc_mddev(GFP_NOIO, 1, rdev->mddev);
        struct completion event;
        rw |= REQ_SYNC | REQ_UNPLUG;
 
        bio->bi_bdev = rdev->bdev;
-       bio->bi_sector = sector;
+       if (metadata_op)
+               bio->bi_sector = sector + rdev->sb_start;
+       else
+               bio->bi_sector = sector + rdev->data_offset;
        bio_add_page(bio, page, size, 0);
        init_completion(&event);
        bio->bi_private = &event;
                return 0;
 
 
-       if (!sync_page_io(rdev, rdev->sb_start, size, rdev->sb_page, READ))
+       if (!sync_page_io(rdev, 0, size, rdev->sb_page, READ, true))
                goto fail;
        rdev->sb_loaded = 1;
        return 0;
 
 extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
                           sector_t sector, int size, struct page *page);
 extern void md_super_wait(mddev_t *mddev);
-extern int sync_page_io(mdk_rdev_t *rdev, sector_t sector, int size,
-                       struct page *page, int rw);
+extern int sync_page_io(mdk_rdev_t *rdev, sector_t sector, int size, 
+                       struct page *page, int rw, bool metadata_op);
 extern void md_do_sync(mddev_t *mddev);
 extern void md_new_event(mddev_t *mddev);
 extern int md_allow_write(mddev_t *mddev);
 
                                         */
                                        rdev = conf->mirrors[d].rdev;
                                        if (sync_page_io(rdev,
-                                                        sect + rdev->data_offset,
+                                                        sect,
                                                         s<<9,
                                                         bio->bi_io_vec[idx].bv_page,
-                                                        READ)) {
+                                                        READ, false)) {
                                                success = 1;
                                                break;
                                        }
                                        rdev = conf->mirrors[d].rdev;
                                        atomic_add(s, &rdev->corrected_errors);
                                        if (sync_page_io(rdev,
-                                                        sect + rdev->data_offset,
+                                                        sect,
                                                         s<<9,
                                                         bio->bi_io_vec[idx].bv_page,
-                                                        WRITE) == 0)
+                                                        WRITE, false) == 0)
                                                md_error(mddev, rdev);
                                }
                                d = start;
                                                continue;
                                        rdev = conf->mirrors[d].rdev;
                                        if (sync_page_io(rdev,
-                                                        sect + rdev->data_offset,
+                                                        sect,
                                                         s<<9,
                                                         bio->bi_io_vec[idx].bv_page,
-                                                        READ) == 0)
+                                                        READ, false) == 0)
                                                md_error(mddev, rdev);
                                }
                        } else {
                        rdev = conf->mirrors[d].rdev;
                        if (rdev &&
                            test_bit(In_sync, &rdev->flags) &&
-                           sync_page_io(rdev,
-                                        sect + rdev->data_offset,
-                                        s<<9,
-                                        conf->tmppage, READ))
+                           sync_page_io(rdev, sect, s<<9,
+                                        conf->tmppage, READ, false))
                                success = 1;
                        else {
                                d++;
                        rdev = conf->mirrors[d].rdev;
                        if (rdev &&
                            test_bit(In_sync, &rdev->flags)) {
-                               if (sync_page_io(rdev,
-                                                sect + rdev->data_offset,
-                                                s<<9, conf->tmppage, WRITE)
+                               if (sync_page_io(rdev, sect, s<<9,
+                                                conf->tmppage, WRITE, false)
                                    == 0)
                                        /* Well, this device is dead */
                                        md_error(mddev, rdev);
                        rdev = conf->mirrors[d].rdev;
                        if (rdev &&
                            test_bit(In_sync, &rdev->flags)) {
-                               if (sync_page_io(rdev,
-                                                sect + rdev->data_offset,
-                                                s<<9, conf->tmppage, READ)
+                               if (sync_page_io(rdev, sect, s<<9,
+                                                conf->tmppage, READ, false)
                                    == 0)
                                        /* Well, this device is dead */
                                        md_error(mddev, rdev);
 
                                rcu_read_unlock();
                                success = sync_page_io(rdev,
                                                       r10_bio->devs[sl].addr +
-                                                      sect + rdev->data_offset,
+                                                      sect,
                                                       s<<9,
-                                                      conf->tmppage, READ);
+                                                      conf->tmppage, READ, false);
                                rdev_dec_pending(rdev, mddev);
                                rcu_read_lock();
                                if (success)
                                atomic_add(s, &rdev->corrected_errors);
                                if (sync_page_io(rdev,
                                                 r10_bio->devs[sl].addr +
-                                                sect + rdev->data_offset,
-                                                s<<9, conf->tmppage, WRITE)
+                                                sect,
+                                                s<<9, conf->tmppage, WRITE, false)
                                    == 0) {
                                        /* Well, this device is dead */
                                        printk(KERN_NOTICE
                                rcu_read_unlock();
                                if (sync_page_io(rdev,
                                                 r10_bio->devs[sl].addr +
-                                                sect + rdev->data_offset,
+                                                sect,
                                                 s<<9, conf->tmppage,
-                                                READ) == 0) {
+                                                READ, false) == 0) {
                                        /* Well, this device is dead */
                                        printk(KERN_NOTICE
                                               "md/raid10:%s: unable to read back "