[PATCH] md: improve handing of read errors with raid6
This is a simple port of match functionality across from raid5. If we get a read error, we don't kick the drive straight away, but try to over-write with good data first. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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ca65b73bd9
commit
d69762e984
1 changed files with 66 additions and 4 deletions
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@ -367,8 +367,8 @@ static void shrink_stripes(raid6_conf_t *conf)
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conf->slab_cache = NULL;
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}
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static int raid6_end_read_request (struct bio * bi, unsigned int bytes_done,
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int error)
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static int raid6_end_read_request(struct bio * bi, unsigned int bytes_done,
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int error)
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{
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struct stripe_head *sh = bi->bi_private;
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raid6_conf_t *conf = sh->raid_conf;
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@ -420,9 +420,35 @@ static int raid6_end_read_request (struct bio * bi, unsigned int bytes_done,
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#else
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set_bit(R5_UPTODATE, &sh->dev[i].flags);
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#endif
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if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
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printk(KERN_INFO "raid6: read error corrected!!\n");
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clear_bit(R5_ReadError, &sh->dev[i].flags);
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clear_bit(R5_ReWrite, &sh->dev[i].flags);
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}
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if (atomic_read(&conf->disks[i].rdev->read_errors))
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atomic_set(&conf->disks[i].rdev->read_errors, 0);
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} else {
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md_error(conf->mddev, conf->disks[i].rdev);
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int retry = 0;
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clear_bit(R5_UPTODATE, &sh->dev[i].flags);
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atomic_inc(&conf->disks[i].rdev->read_errors);
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if (conf->mddev->degraded)
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printk(KERN_WARNING "raid6: read error not correctable.\n");
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else if (test_bit(R5_ReWrite, &sh->dev[i].flags))
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/* Oh, no!!! */
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printk(KERN_WARNING "raid6: read error NOT corrected!!\n");
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else if (atomic_read(&conf->disks[i].rdev->read_errors)
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> conf->max_nr_stripes)
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printk(KERN_WARNING
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"raid6: Too many read errors, failing device.\n");
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else
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retry = 1;
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if (retry)
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set_bit(R5_ReadError, &sh->dev[i].flags);
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else {
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clear_bit(R5_ReadError, &sh->dev[i].flags);
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clear_bit(R5_ReWrite, &sh->dev[i].flags);
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md_error(conf->mddev, conf->disks[i].rdev);
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}
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}
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rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
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#if 0
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@ -1079,6 +1105,12 @@ static void handle_stripe(struct stripe_head *sh, struct page *tmp_page)
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if (dev->written) written++;
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rdev = conf->disks[i].rdev; /* FIXME, should I be looking rdev */
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if (!rdev || !test_bit(In_sync, &rdev->flags)) {
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/* The ReadError flag will just be confusing now */
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clear_bit(R5_ReadError, &dev->flags);
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clear_bit(R5_ReWrite, &dev->flags);
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}
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if (!rdev || !test_bit(In_sync, &rdev->flags)
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|| test_bit(R5_ReadError, &dev->flags)) {
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if ( failed < 2 )
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failed_num[failed] = i;
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failed++;
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@ -1095,6 +1127,14 @@ static void handle_stripe(struct stripe_head *sh, struct page *tmp_page)
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if (failed > 2 && to_read+to_write+written) {
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for (i=disks; i--; ) {
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int bitmap_end = 0;
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if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
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mdk_rdev_t *rdev = conf->disks[i].rdev;
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if (rdev && test_bit(In_sync, &rdev->flags))
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/* multiple read failures in one stripe */
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md_error(conf->mddev, rdev);
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}
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spin_lock_irq(&conf->device_lock);
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/* fail all writes first */
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bi = sh->dev[i].towrite;
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@ -1130,7 +1170,8 @@ static void handle_stripe(struct stripe_head *sh, struct page *tmp_page)
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}
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/* fail any reads if this device is non-operational */
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if (!test_bit(R5_Insync, &sh->dev[i].flags)) {
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if (!test_bit(R5_Insync, &sh->dev[i].flags) ||
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test_bit(R5_ReadError, &sh->dev[i].flags)) {
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bi = sh->dev[i].toread;
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sh->dev[i].toread = NULL;
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if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
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@ -1457,6 +1498,27 @@ static void handle_stripe(struct stripe_head *sh, struct page *tmp_page)
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clear_bit(STRIPE_SYNCING, &sh->state);
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}
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/* If the failed drives are just a ReadError, then we might need
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* to progress the repair/check process
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*/
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if (failed <= 2 && ! conf->mddev->ro)
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for (i=0; i<failed;i++) {
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dev = &sh->dev[failed_num[i]];
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if (test_bit(R5_ReadError, &dev->flags)
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&& !test_bit(R5_LOCKED, &dev->flags)
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&& test_bit(R5_UPTODATE, &dev->flags)
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) {
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if (!test_bit(R5_ReWrite, &dev->flags)) {
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set_bit(R5_Wantwrite, &dev->flags);
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set_bit(R5_ReWrite, &dev->flags);
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set_bit(R5_LOCKED, &dev->flags);
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} else {
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/* let's read it back */
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set_bit(R5_Wantread, &dev->flags);
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set_bit(R5_LOCKED, &dev->flags);
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}
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}
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}
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spin_unlock(&sh->lock);
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while ((bi=return_bi)) {
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