[PATCH] md: improvements to raid5 handling of read errors
Two refinements to the 'attempt-overwrite-on-read-error' mechanism.
1/ If the array is read-only, don't attempt an over-write.
2/ If there are more than max_nr_stripes read errors on a device with
no success, fail the drive. This will make sure a dead
drive will be eventually kicked even when we aren't trying
to rewrite (which would normally kick a dead drive more quickly.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 08a1620b..77610b9 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -420,21 +420,29 @@
clear_bit(R5_ReadError, &sh->dev[i].flags);
clear_bit(R5_ReWrite, &sh->dev[i].flags);
}
+ if (atomic_read(&conf->disks[i].rdev->read_errors))
+ atomic_set(&conf->disks[i].rdev->read_errors, 0);
} else {
+ int retry = 0;
clear_bit(R5_UPTODATE, &sh->dev[i].flags);
- if (conf->mddev->degraded) {
+ atomic_inc(&conf->disks[i].rdev->read_errors);
+ if (conf->mddev->degraded)
printk("R5: read error not correctable.\n");
- clear_bit(R5_ReadError, &sh->dev[i].flags);
- clear_bit(R5_ReWrite, &sh->dev[i].flags);
- md_error(conf->mddev, conf->disks[i].rdev);
- } else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
+ else if (test_bit(R5_ReWrite, &sh->dev[i].flags))
/* Oh, no!!! */
printk("R5: read error NOT corrected!!\n");
+ else if (atomic_read(&conf->disks[i].rdev->read_errors)
+ > conf->max_nr_stripes)
+ printk("raid5: Too many read errors, failing device.\n");
+ else
+ retry = 1;
+ if (retry)
+ set_bit(R5_ReadError, &sh->dev[i].flags);
+ else {
clear_bit(R5_ReadError, &sh->dev[i].flags);
clear_bit(R5_ReWrite, &sh->dev[i].flags);
md_error(conf->mddev, conf->disks[i].rdev);
- } else
- set_bit(R5_ReadError, &sh->dev[i].flags);
+ }
}
rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
#if 0
@@ -1328,7 +1336,8 @@
/* If the failed drive is just a ReadError, then we might need to progress
* the repair/check process
*/
- if (failed == 1 && test_bit(R5_ReadError, &sh->dev[failed_num].flags)
+ if (failed == 1 && ! conf->mddev->ro &&
+ test_bit(R5_ReadError, &sh->dev[failed_num].flags)
&& !test_bit(R5_LOCKED, &sh->dev[failed_num].flags)
&& test_bit(R5_UPTODATE, &sh->dev[failed_num].flags)
) {
