From: NeilBrown There is severe bit-rot in this code, which is to say that it doesn't work at all: an io error during read will do bad things. It should work better with this patch. Signed-off-by: Neil Brown Signed-off-by: Andrew Morton --- 25-akpm/drivers/md/raid1.c | 10 +++++++--- 1 files changed, 7 insertions(+), 3 deletions(-) diff -puN drivers/md/raid1.c~md-fix-up-handling-for-read-error-in-raid1 drivers/md/raid1.c --- 25/drivers/md/raid1.c~md-fix-up-handling-for-read-error-in-raid1 2004-06-23 21:44:56.006551544 -0700 +++ 25-akpm/drivers/md/raid1.c 2004-06-23 21:44:56.011550784 -0700 @@ -206,7 +206,7 @@ static int map(mddev_t *mddev, mdk_rdev_ *rdevp = rdev; atomic_inc(&rdev->nr_pending); spin_unlock_irq(&conf->device_lock); - return 0; + return i; } } spin_unlock_irq(&conf->device_lock); @@ -945,18 +945,22 @@ static void raid1d(mddev_t *mddev) mddev = r1_bio->mddev; conf = mddev_to_conf(mddev); - bio = r1_bio->master_bio; if (test_bit(R1BIO_IsSync, &r1_bio->state)) { sync_request_write(mddev, r1_bio); unplug = 1; } else { - if (map(mddev, &rdev) == -1) { + int disk; + bio = r1_bio->bios[r1_bio->read_disk]; + if ((disk=map(mddev, &rdev)) == -1) { printk(KERN_ALERT "raid1: %s: unrecoverable I/O" " read error for block %llu\n", bdevname(bio->bi_bdev,b), (unsigned long long)r1_bio->sector); raid_end_bio_io(r1_bio); } else { + r1_bio->bios[r1_bio->read_disk] = NULL; + r1_bio->read_disk = disk; + r1_bio->bios[r1_bio->read_disk] = bio; printk(KERN_ERR "raid1: %s: redirecting sector %llu to" " another mirror\n", bdevname(rdev->bdev,b), _