+
+ if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
+ /* We have read all readable devices. If we haven't
+ * got the block, then there is no hope left.
+ * If we have, then we want to do a comparison
+ * and skip the write if everything is the same.
+ * If any blocks failed to read, then we need to
+ * attempt an over-write
+ */
+ int primary;
+ if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
+ for (i=0; i<mddev->raid_disks; i++)
+ if (r1_bio->bios[i]->bi_end_io == end_sync_read)
+ md_error(mddev, conf->mirrors[i].rdev);
+
+ md_done_sync(mddev, r1_bio->sectors, 1);
+ put_buf(r1_bio);
+ return;
+ }
+ for (primary=0; primary<mddev->raid_disks; primary++)
+ if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
+ test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
+ r1_bio->bios[primary]->bi_end_io = NULL;
+ rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
+ break;
+ }
+ r1_bio->read_disk = primary;
+ for (i=0; i<mddev->raid_disks; i++)
+ if (r1_bio->bios[i]->bi_end_io == end_sync_read &&
+ test_bit(BIO_UPTODATE, &r1_bio->bios[i]->bi_flags)) {
+ int j;
+ int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
+ struct bio *pbio = r1_bio->bios[primary];
+ struct bio *sbio = r1_bio->bios[i];
+ for (j = vcnt; j-- ; )
+ if (memcmp(page_address(pbio->bi_io_vec[j].bv_page),
+ page_address(sbio->bi_io_vec[j].bv_page),
+ PAGE_SIZE))
+ break;
+ if (j >= 0)
+ mddev->resync_mismatches += r1_bio->sectors;
+ if (j < 0 || test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) {
+ sbio->bi_end_io = NULL;
+ rdev_dec_pending(conf->mirrors[i].rdev, mddev);
+ } else {
+ /* fixup the bio for reuse */
+ sbio->bi_vcnt = vcnt;
+ sbio->bi_size = r1_bio->sectors << 9;
+ sbio->bi_idx = 0;
+ sbio->bi_phys_segments = 0;
+ sbio->bi_hw_segments = 0;
+ sbio->bi_hw_front_size = 0;
+ sbio->bi_hw_back_size = 0;
+ sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
+ sbio->bi_flags |= 1 << BIO_UPTODATE;
+ sbio->bi_next = NULL;
+ sbio->bi_sector = r1_bio->sector +
+ conf->mirrors[i].rdev->data_offset;
+ sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
+ for (j = 0; j < vcnt ; j++)
+ memcpy(page_address(sbio->bi_io_vec[j].bv_page),
+ page_address(pbio->bi_io_vec[j].bv_page),
+ PAGE_SIZE);
+
+ }
+ }
+ }