md: avoid a possibility that a read error can wrongly propagate through md/raid1...

[linux-2.6-block.git] / drivers / md / raid1.c

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 97ee870b265d866ffa818bdf83dc7f551cd40d7b..3a95cc5e029c932eaddf0b85df6d6b0f744c36b8 100644 (file)
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -271,21 +271,25 @@ static int raid1_end_read_request(struct bio *bio, unsigned int bytes_done, int
         */
        update_head_pos(mirror, r1_bio);
 
-       if (uptodate || (conf->raid_disks - conf->mddev->degraded) <= 1) {
-               /*
-                * Set R1BIO_Uptodate in our master bio, so that
-                * we will return a good error code for to the higher
-                * levels even if IO on some other mirrored buffer fails.
-                *
-                * The 'master' represents the composite IO operation to
-                * user-side. So if something waits for IO, then it will
-                * wait for the 'master' bio.
+       if (uptodate)
+               set_bit(R1BIO_Uptodate, &r1_bio->state);
+       else {
+               /* If all other devices have failed, we want to return
+                * the error upwards rather than fail the last device.
+                * Here we redefine "uptodate" to mean "Don't want to retry"
                 */
-               if (uptodate)
-                       set_bit(R1BIO_Uptodate, &r1_bio->state);
+               unsigned long flags;
+               spin_lock_irqsave(&conf->device_lock, flags);
+               if (r1_bio->mddev->degraded == conf->raid_disks ||
+                   (r1_bio->mddev->degraded == conf->raid_disks-1 &&
+                    !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags)))
+                       uptodate = 1;
+               spin_unlock_irqrestore(&conf->device_lock, flags);
+       }
 
+       if (uptodate)
                raid_end_bio_io(r1_bio);
-       } else {
+       else {
                /*
                 * oops, read error:
                 */
@@ -992,13 +996,14 @@ static void error(mddev_t *mddev, mdk_rdev_t *rdev)
                unsigned long flags;
                spin_lock_irqsave(&conf->device_lock, flags);
                mddev->degraded++;
+               set_bit(Faulty, &rdev->flags);
                spin_unlock_irqrestore(&conf->device_lock, flags);
                /*
                 * if recovery is running, make sure it aborts.
                 */
                set_bit(MD_RECOVERY_ERR, &mddev->recovery);
-       }
-       set_bit(Faulty, &rdev->flags);
+       } else
+               set_bit(Faulty, &rdev->flags);
        set_bit(MD_CHANGE_DEVS, &mddev->flags);
        printk(KERN_ALERT "raid1: Disk failure on %s, disabling device. \n"
                "       Operation continuing on %d devices\n",