Commit d69762e9 authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds

[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: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent ca65b73b
......@@ -367,8 +367,8 @@ static void shrink_stripes(raid6_conf_t *conf)
conf->slab_cache = NULL;
}
static int raid6_end_read_request (struct bio * bi, unsigned int bytes_done,
int error)
static int raid6_end_read_request(struct bio * bi, unsigned int bytes_done,
int error)
{
struct stripe_head *sh = bi->bi_private;
raid6_conf_t *conf = sh->raid_conf;
......@@ -420,9 +420,35 @@ static int raid6_end_read_request (struct bio * bi, unsigned int bytes_done,
#else
set_bit(R5_UPTODATE, &sh->dev[i].flags);
#endif
if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
printk(KERN_INFO "raid6: read error corrected!!\n");
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 {
md_error(conf->mddev, conf->disks[i].rdev);
int retry = 0;
clear_bit(R5_UPTODATE, &sh->dev[i].flags);
atomic_inc(&conf->disks[i].rdev->read_errors);
if (conf->mddev->degraded)
printk(KERN_WARNING "raid6: read error not correctable.\n");
else if (test_bit(R5_ReWrite, &sh->dev[i].flags))
/* Oh, no!!! */
printk(KERN_WARNING "raid6: read error NOT corrected!!\n");
else if (atomic_read(&conf->disks[i].rdev->read_errors)
> conf->max_nr_stripes)
printk(KERN_WARNING
"raid6: 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);
}
}
rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
#if 0
......@@ -1079,6 +1105,12 @@ static void handle_stripe(struct stripe_head *sh, struct page *tmp_page)
if (dev->written) written++;
rdev = conf->disks[i].rdev; /* FIXME, should I be looking rdev */
if (!rdev || !test_bit(In_sync, &rdev->flags)) {
/* The ReadError flag will just be confusing now */
clear_bit(R5_ReadError, &dev->flags);
clear_bit(R5_ReWrite, &dev->flags);
}
if (!rdev || !test_bit(In_sync, &rdev->flags)
|| test_bit(R5_ReadError, &dev->flags)) {
if ( failed < 2 )
failed_num[failed] = i;
failed++;
......@@ -1095,6 +1127,14 @@ static void handle_stripe(struct stripe_head *sh, struct page *tmp_page)
if (failed > 2 && to_read+to_write+written) {
for (i=disks; i--; ) {
int bitmap_end = 0;
if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
mdk_rdev_t *rdev = conf->disks[i].rdev;
if (rdev && test_bit(In_sync, &rdev->flags))
/* multiple read failures in one stripe */
md_error(conf->mddev, rdev);
}
spin_lock_irq(&conf->device_lock);
/* fail all writes first */
bi = sh->dev[i].towrite;
......@@ -1130,7 +1170,8 @@ static void handle_stripe(struct stripe_head *sh, struct page *tmp_page)
}
/* fail any reads if this device is non-operational */
if (!test_bit(R5_Insync, &sh->dev[i].flags)) {
if (!test_bit(R5_Insync, &sh->dev[i].flags) ||
test_bit(R5_ReadError, &sh->dev[i].flags)) {
bi = sh->dev[i].toread;
sh->dev[i].toread = NULL;
if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
......@@ -1457,6 +1498,27 @@ static void handle_stripe(struct stripe_head *sh, struct page *tmp_page)
clear_bit(STRIPE_SYNCING, &sh->state);
}
/* If the failed drives are just a ReadError, then we might need
* to progress the repair/check process
*/
if (failed <= 2 && ! conf->mddev->ro)
for (i=0; i<failed;i++) {
dev = &sh->dev[failed_num[i]];
if (test_bit(R5_ReadError, &dev->flags)
&& !test_bit(R5_LOCKED, &dev->flags)
&& test_bit(R5_UPTODATE, &dev->flags)
) {
if (!test_bit(R5_ReWrite, &dev->flags)) {
set_bit(R5_Wantwrite, &dev->flags);
set_bit(R5_ReWrite, &dev->flags);
set_bit(R5_LOCKED, &dev->flags);
} else {
/* let's read it back */
set_bit(R5_Wantread, &dev->flags);
set_bit(R5_LOCKED, &dev->flags);
}
}
}
spin_unlock(&sh->lock);
while ((bi=return_bi)) {
......
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