Commit 6bfe0b49 authored by Dan Williams's avatar Dan Williams Committed by Linus Torvalds

md: support blocking writes to an array on device failure

Allows a userspace metadata handler to take action upon detecting a device
failure.

Based on an original patch by Neil Brown.

Changes:
-added blocked_wait waitqueue to rdev
-don't qualify Blocked with Faulty always let userspace block writes
-added md_wait_for_blocked_rdev to wait for the block device to be clear, if
 userspace misses the notification another one is sent every 5 seconds
-set MD_RECOVERY_NEEDED after clearing "blocked"
-kill DoBlock flag, just test mddev->external
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 11e2ede0
......@@ -1828,6 +1828,10 @@ state_show(mdk_rdev_t *rdev, char *page)
len += sprintf(page+len, "%swrite_mostly",sep);
sep = ",";
}
if (test_bit(Blocked, &rdev->flags)) {
len += sprintf(page+len, "%sblocked", sep);
sep = ",";
}
if (!test_bit(Faulty, &rdev->flags) &&
!test_bit(In_sync, &rdev->flags)) {
len += sprintf(page+len, "%sspare", sep);
......@@ -1844,6 +1848,8 @@ state_store(mdk_rdev_t *rdev, const char *buf, size_t len)
* remove - disconnects the device
* writemostly - sets write_mostly
* -writemostly - clears write_mostly
* blocked - sets the Blocked flag
* -blocked - clears the Blocked flag
*/
int err = -EINVAL;
if (cmd_match(buf, "faulty") && rdev->mddev->pers) {
......@@ -1865,6 +1871,16 @@ state_store(mdk_rdev_t *rdev, const char *buf, size_t len)
err = 0;
} else if (cmd_match(buf, "-writemostly")) {
clear_bit(WriteMostly, &rdev->flags);
err = 0;
} else if (cmd_match(buf, "blocked")) {
set_bit(Blocked, &rdev->flags);
err = 0;
} else if (cmd_match(buf, "-blocked")) {
clear_bit(Blocked, &rdev->flags);
wake_up(&rdev->blocked_wait);
set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
md_wakeup_thread(rdev->mddev->thread);
err = 0;
}
return err ? err : len;
......@@ -2194,7 +2210,9 @@ static mdk_rdev_t *md_import_device(dev_t newdev, int super_format, int super_mi
goto abort_free;
}
}
INIT_LIST_HEAD(&rdev->same_set);
init_waitqueue_head(&rdev->blocked_wait);
return rdev;
......@@ -4958,6 +4976,9 @@ void md_error(mddev_t *mddev, mdk_rdev_t *rdev)
if (!rdev || test_bit(Faulty, &rdev->flags))
return;
if (mddev->external)
set_bit(Blocked, &rdev->flags);
/*
dprintk("md_error dev:%s, rdev:(%d:%d), (caller: %p,%p,%p,%p).\n",
mdname(mddev),
......@@ -5760,7 +5781,7 @@ static int remove_and_add_spares(mddev_t *mddev)
rdev_for_each(rdev, rtmp, mddev)
if (rdev->raid_disk >= 0 &&
!mddev->external &&
!test_bit(Blocked, &rdev->flags) &&
(test_bit(Faulty, &rdev->flags) ||
! test_bit(In_sync, &rdev->flags)) &&
atomic_read(&rdev->nr_pending)==0) {
......@@ -5959,6 +5980,16 @@ void md_check_recovery(mddev_t *mddev)
}
}
void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
{
sysfs_notify(&rdev->kobj, NULL, "state");
wait_event_timeout(rdev->blocked_wait,
!test_bit(Blocked, &rdev->flags),
msecs_to_jiffies(5000));
rdev_dec_pending(rdev, mddev);
}
EXPORT_SYMBOL(md_wait_for_blocked_rdev);
static int md_notify_reboot(struct notifier_block *this,
unsigned long code, void *x)
{
......
......@@ -773,7 +773,6 @@ static int make_request(struct request_queue *q, struct bio * bio)
r1bio_t *r1_bio;
struct bio *read_bio;
int i, targets = 0, disks;
mdk_rdev_t *rdev;
struct bitmap *bitmap = mddev->bitmap;
unsigned long flags;
struct bio_list bl;
......@@ -781,6 +780,7 @@ static int make_request(struct request_queue *q, struct bio * bio)
const int rw = bio_data_dir(bio);
const int do_sync = bio_sync(bio);
int do_barriers;
mdk_rdev_t *blocked_rdev;
/*
* Register the new request and wait if the reconstruction
......@@ -862,10 +862,17 @@ static int make_request(struct request_queue *q, struct bio * bio)
first = 0;
}
#endif
retry_write:
blocked_rdev = NULL;
rcu_read_lock();
for (i = 0; i < disks; i++) {
if ((rdev=rcu_dereference(conf->mirrors[i].rdev)) != NULL &&
!test_bit(Faulty, &rdev->flags)) {
mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
atomic_inc(&rdev->nr_pending);
blocked_rdev = rdev;
break;
}
if (rdev && !test_bit(Faulty, &rdev->flags)) {
atomic_inc(&rdev->nr_pending);
if (test_bit(Faulty, &rdev->flags)) {
rdev_dec_pending(rdev, mddev);
......@@ -878,6 +885,20 @@ static int make_request(struct request_queue *q, struct bio * bio)
}
rcu_read_unlock();
if (unlikely(blocked_rdev)) {
/* Wait for this device to become unblocked */
int j;
for (j = 0; j < i; j++)
if (r1_bio->bios[j])
rdev_dec_pending(conf->mirrors[j].rdev, mddev);
allow_barrier(conf);
md_wait_for_blocked_rdev(blocked_rdev, mddev);
wait_barrier(conf);
goto retry_write;
}
BUG_ON(targets == 0); /* we never fail the last device */
if (targets < conf->raid_disks) {
......
......@@ -790,6 +790,7 @@ static int make_request(struct request_queue *q, struct bio * bio)
const int do_sync = bio_sync(bio);
struct bio_list bl;
unsigned long flags;
mdk_rdev_t *blocked_rdev;
if (unlikely(bio_barrier(bio))) {
bio_endio(bio, -EOPNOTSUPP);
......@@ -879,17 +880,23 @@ static int make_request(struct request_queue *q, struct bio * bio)
/*
* WRITE:
*/
/* first select target devices under spinlock and
/* first select target devices under rcu_lock and
* inc refcount on their rdev. Record them by setting
* bios[x] to bio
*/
raid10_find_phys(conf, r10_bio);
retry_write:
blocked_rdev = 0;
rcu_read_lock();
for (i = 0; i < conf->copies; i++) {
int d = r10_bio->devs[i].devnum;
mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[d].rdev);
if (rdev &&
!test_bit(Faulty, &rdev->flags)) {
if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
atomic_inc(&rdev->nr_pending);
blocked_rdev = rdev;
break;
}
if (rdev && !test_bit(Faulty, &rdev->flags)) {
atomic_inc(&rdev->nr_pending);
r10_bio->devs[i].bio = bio;
} else {
......@@ -899,6 +906,22 @@ static int make_request(struct request_queue *q, struct bio * bio)
}
rcu_read_unlock();
if (unlikely(blocked_rdev)) {
/* Have to wait for this device to get unblocked, then retry */
int j;
int d;
for (j = 0; j < i; j++)
if (r10_bio->devs[j].bio) {
d = r10_bio->devs[j].devnum;
rdev_dec_pending(conf->mirrors[d].rdev, mddev);
}
allow_barrier(conf);
md_wait_for_blocked_rdev(blocked_rdev, mddev);
wait_barrier(conf);
goto retry_write;
}
atomic_set(&r10_bio->remaining, 0);
bio_list_init(&bl);
......
......@@ -2607,6 +2607,7 @@ static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh,
}
}
/*
* handle_stripe - do things to a stripe.
*
......@@ -2632,6 +2633,7 @@ static void handle_stripe5(struct stripe_head *sh)
struct stripe_head_state s;
struct r5dev *dev;
unsigned long pending = 0;
mdk_rdev_t *blocked_rdev = NULL;
memset(&s, 0, sizeof(s));
pr_debug("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d "
......@@ -2691,6 +2693,11 @@ static void handle_stripe5(struct stripe_head *sh)
if (dev->written)
s.written++;
rdev = rcu_dereference(conf->disks[i].rdev);
if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
blocked_rdev = rdev;
atomic_inc(&rdev->nr_pending);
break;
}
if (!rdev || !test_bit(In_sync, &rdev->flags)) {
/* The ReadError flag will just be confusing now */
clear_bit(R5_ReadError, &dev->flags);
......@@ -2705,6 +2712,11 @@ static void handle_stripe5(struct stripe_head *sh)
}
rcu_read_unlock();
if (unlikely(blocked_rdev)) {
set_bit(STRIPE_HANDLE, &sh->state);
goto unlock;
}
if (s.to_fill && !test_and_set_bit(STRIPE_OP_BIOFILL, &sh->ops.pending))
sh->ops.count++;
......@@ -2894,8 +2906,13 @@ static void handle_stripe5(struct stripe_head *sh)
if (sh->ops.count)
pending = get_stripe_work(sh);
unlock:
spin_unlock(&sh->lock);
/* wait for this device to become unblocked */
if (unlikely(blocked_rdev))
md_wait_for_blocked_rdev(blocked_rdev, conf->mddev);
if (pending)
raid5_run_ops(sh, pending);
......@@ -2912,6 +2929,7 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
struct stripe_head_state s;
struct r6_state r6s;
struct r5dev *dev, *pdev, *qdev;
mdk_rdev_t *blocked_rdev = NULL;
r6s.qd_idx = raid6_next_disk(pd_idx, disks);
pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
......@@ -2975,6 +2993,11 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
if (dev->written)
s.written++;
rdev = rcu_dereference(conf->disks[i].rdev);
if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
blocked_rdev = rdev;
atomic_inc(&rdev->nr_pending);
break;
}
if (!rdev || !test_bit(In_sync, &rdev->flags)) {
/* The ReadError flag will just be confusing now */
clear_bit(R5_ReadError, &dev->flags);
......@@ -2989,6 +3012,11 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
set_bit(R5_Insync, &dev->flags);
}
rcu_read_unlock();
if (unlikely(blocked_rdev)) {
set_bit(STRIPE_HANDLE, &sh->state);
goto unlock;
}
pr_debug("locked=%d uptodate=%d to_read=%d"
" to_write=%d failed=%d failed_num=%d,%d\n",
s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
......@@ -3094,8 +3122,13 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
!test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending))
handle_stripe_expansion(conf, sh, &r6s);
unlock:
spin_unlock(&sh->lock);
/* wait for this device to become unblocked */
if (unlikely(blocked_rdev))
md_wait_for_blocked_rdev(blocked_rdev, conf->mddev);
return_io(return_bi);
for (i=disks; i-- ;) {
......
......@@ -94,6 +94,7 @@ extern int sync_page_io(struct block_device *bdev, sector_t sector, int size,
extern void md_do_sync(mddev_t *mddev);
extern void md_new_event(mddev_t *mddev);
extern void md_allow_write(mddev_t *mddev);
extern void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
#endif /* CONFIG_MD */
#endif
......
......@@ -84,6 +84,10 @@ struct mdk_rdev_s
#define AllReserved 6 /* If whole device is reserved for
* one array */
#define AutoDetected 7 /* added by auto-detect */
#define Blocked 8 /* An error occured on an externally
* managed array, don't allow writes
* until it is cleared */
wait_queue_head_t blocked_wait;
int desc_nr; /* descriptor index in the superblock */
int raid_disk; /* role of device in array */
......
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