Commit 4443ae10 authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds

[PATCH] md: auto-correct correctable read errors in raid10

Largely just a cross-port from raid1.
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 220946c9
......@@ -209,6 +209,7 @@ static void reschedule_retry(r10bio_t *r10_bio)
spin_lock_irqsave(&conf->device_lock, flags);
list_add(&r10_bio->retry_list, &conf->retry_list);
conf->nr_queued ++;
spin_unlock_irqrestore(&conf->device_lock, flags);
md_wakeup_thread(mddev->thread);
......@@ -254,9 +255,9 @@ static int raid10_end_read_request(struct bio *bio, unsigned int bytes_done, int
/*
* this branch is our 'one mirror IO has finished' event handler:
*/
if (!uptodate)
md_error(r10_bio->mddev, conf->mirrors[dev].rdev);
else
update_head_pos(slot, r10_bio);
if (uptodate) {
/*
* Set R10BIO_Uptodate in our master bio, so that
* we will return a good error code to the higher
......@@ -267,15 +268,8 @@ static int raid10_end_read_request(struct bio *bio, unsigned int bytes_done, int
* wait for the 'master' bio.
*/
set_bit(R10BIO_Uptodate, &r10_bio->state);
update_head_pos(slot, r10_bio);
/*
* we have only one bio on the read side
*/
if (uptodate)
raid_end_bio_io(r10_bio);
else {
} else {
/*
* oops, read error:
*/
......@@ -714,6 +708,33 @@ static void allow_barrier(conf_t *conf)
wake_up(&conf->wait_barrier);
}
static void freeze_array(conf_t *conf)
{
/* stop syncio and normal IO and wait for everything to
* go quite.
* We increment barrier and nr_waiting, and then
* wait until barrier+nr_pending match nr_queued+2
*/
spin_lock_irq(&conf->resync_lock);
conf->barrier++;
conf->nr_waiting++;
wait_event_lock_irq(conf->wait_barrier,
conf->barrier+conf->nr_pending == conf->nr_queued+2,
conf->resync_lock,
raid10_unplug(conf->mddev->queue));
spin_unlock_irq(&conf->resync_lock);
}
static void unfreeze_array(conf_t *conf)
{
/* reverse the effect of the freeze */
spin_lock_irq(&conf->resync_lock);
conf->barrier--;
conf->nr_waiting--;
wake_up(&conf->wait_barrier);
spin_unlock_irq(&conf->resync_lock);
}
static int make_request(request_queue_t *q, struct bio * bio)
{
mddev_t *mddev = q->queuedata;
......@@ -1338,6 +1359,7 @@ static void raid10d(mddev_t *mddev)
break;
r10_bio = list_entry(head->prev, r10bio_t, retry_list);
list_del(head->prev);
conf->nr_queued--;
spin_unlock_irqrestore(&conf->device_lock, flags);
mddev = r10_bio->mddev;
......@@ -1350,6 +1372,78 @@ static void raid10d(mddev_t *mddev)
unplug = 1;
} else {
int mirror;
/* we got a read error. Maybe the drive is bad. Maybe just
* the block and we can fix it.
* We freeze all other IO, and try reading the block from
* other devices. When we find one, we re-write
* and check it that fixes the read error.
* This is all done synchronously while the array is
* frozen.
*/
int sect = 0; /* Offset from r10_bio->sector */
int sectors = r10_bio->sectors;
freeze_array(conf);
if (mddev->ro == 0) while(sectors) {
int s = sectors;
int sl = r10_bio->read_slot;
int success = 0;
if (s > (PAGE_SIZE>>9))
s = PAGE_SIZE >> 9;
do {
int d = r10_bio->devs[sl].devnum;
rdev = conf->mirrors[d].rdev;
if (rdev &&
test_bit(In_sync, &rdev->flags) &&
sync_page_io(rdev->bdev,
r10_bio->devs[sl].addr +
sect + rdev->data_offset,
s<<9,
conf->tmppage, READ))
success = 1;
else {
sl++;
if (sl == conf->copies)
sl = 0;
}
} while (!success && sl != r10_bio->read_slot);
if (success) {
/* write it back and re-read */
while (sl != r10_bio->read_slot) {
int d;
if (sl==0)
sl = conf->copies;
sl--;
d = r10_bio->devs[sl].devnum;
rdev = conf->mirrors[d].rdev;
if (rdev &&
test_bit(In_sync, &rdev->flags)) {
if (sync_page_io(rdev->bdev,
r10_bio->devs[sl].addr +
sect + rdev->data_offset,
s<<9, conf->tmppage, WRITE) == 0 ||
sync_page_io(rdev->bdev,
r10_bio->devs[sl].addr +
sect + rdev->data_offset,
s<<9, conf->tmppage, READ) == 0) {
/* Well, this device is dead */
md_error(mddev, rdev);
}
}
}
} else {
/* Cannot read from anywhere -- bye bye array */
md_error(mddev, conf->mirrors[r10_bio->devs[r10_bio->read_slot].devnum].rdev);
break;
}
sectors -= s;
sect += s;
}
unfreeze_array(conf);
bio = r10_bio->devs[r10_bio->read_slot].bio;
r10_bio->devs[r10_bio->read_slot].bio = NULL;
bio_put(bio);
......@@ -1793,22 +1887,24 @@ static int run(mddev_t *mddev)
* bookkeeping area. [whatever we allocate in run(),
* should be freed in stop()]
*/
conf = kmalloc(sizeof(conf_t), GFP_KERNEL);
conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
mddev->private = conf;
if (!conf) {
printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
mdname(mddev));
goto out;
}
memset(conf, 0, sizeof(*conf));
conf->mirrors = kmalloc(sizeof(struct mirror_info)*mddev->raid_disks,
conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
GFP_KERNEL);
if (!conf->mirrors) {
printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
mdname(mddev));
goto out_free_conf;
}
memset(conf->mirrors, 0, sizeof(struct mirror_info)*mddev->raid_disks);
conf->tmppage = alloc_page(GFP_KERNEL);
if (!conf->tmppage)
goto out_free_conf;
conf->near_copies = nc;
conf->far_copies = fc;
......@@ -1918,6 +2014,7 @@ static int run(mddev_t *mddev)
out_free_conf:
if (conf->r10bio_pool)
mempool_destroy(conf->r10bio_pool);
put_page(conf->tmppage);
kfree(conf->mirrors);
kfree(conf);
mddev->private = NULL;
......
......@@ -42,6 +42,7 @@ struct r10_private_data_s {
spinlock_t resync_lock;
int nr_pending;
int nr_waiting;
int nr_queued;
int barrier;
sector_t next_resync;
int fullsync; /* set to 1 if a full sync is needed,
......@@ -53,6 +54,7 @@ struct r10_private_data_s {
mempool_t *r10bio_pool;
mempool_t *r10buf_pool;
struct page *tmppage;
};
typedef struct r10_private_data_s conf_t;
......
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