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-rw-r--r--drivers/md/linear.c2
-rw-r--r--drivers/md/md.c105
-rw-r--r--drivers/md/md.h12
-rw-r--r--drivers/md/multipath.c2
-rw-r--r--drivers/md/raid0.c2
-rw-r--r--drivers/md/raid10.c2
-rw-r--r--drivers/md/raid5.c8
7 files changed, 126 insertions, 7 deletions
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 1ceceb334d5e..3b3f77c4f249 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -292,7 +292,7 @@ static int linear_make_request (struct request_queue *q, struct bio *bio)
int cpu;
if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) {
- bio_endio(bio, -EOPNOTSUPP);
+ md_barrier_request(mddev, bio);
return 0;
}
diff --git a/drivers/md/md.c b/drivers/md/md.c
index d79a40649799..569f25183db6 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -213,12 +213,12 @@ static int md_make_request(struct request_queue *q, struct bio *bio)
return 0;
}
rcu_read_lock();
- if (mddev->suspended) {
+ if (mddev->suspended || mddev->barrier) {
DEFINE_WAIT(__wait);
for (;;) {
prepare_to_wait(&mddev->sb_wait, &__wait,
TASK_UNINTERRUPTIBLE);
- if (!mddev->suspended)
+ if (!mddev->suspended && !mddev->barrier)
break;
rcu_read_unlock();
schedule();
@@ -260,10 +260,110 @@ static void mddev_resume(mddev_t *mddev)
int mddev_congested(mddev_t *mddev, int bits)
{
+ if (mddev->barrier)
+ return 1;
return mddev->suspended;
}
EXPORT_SYMBOL(mddev_congested);
+/*
+ * Generic barrier handling for md
+ */
+
+#define POST_REQUEST_BARRIER ((void*)1)
+
+static void md_end_barrier(struct bio *bio, int err)
+{
+ mdk_rdev_t *rdev = bio->bi_private;
+ mddev_t *mddev = rdev->mddev;
+ if (err == -EOPNOTSUPP && mddev->barrier != POST_REQUEST_BARRIER)
+ set_bit(BIO_EOPNOTSUPP, &mddev->barrier->bi_flags);
+
+ rdev_dec_pending(rdev, mddev);
+
+ if (atomic_dec_and_test(&mddev->flush_pending)) {
+ if (mddev->barrier == POST_REQUEST_BARRIER) {
+ /* This was a post-request barrier */
+ mddev->barrier = NULL;
+ wake_up(&mddev->sb_wait);
+ } else
+ /* The pre-request barrier has finished */
+ schedule_work(&mddev->barrier_work);
+ }
+ bio_put(bio);
+}
+
+static void submit_barriers(mddev_t *mddev)
+{
+ mdk_rdev_t *rdev;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(rdev, &mddev->disks, same_set)
+ if (rdev->raid_disk >= 0 &&
+ !test_bit(Faulty, &rdev->flags)) {
+ /* Take two references, one is dropped
+ * when request finishes, one after
+ * we reclaim rcu_read_lock
+ */
+ struct bio *bi;
+ atomic_inc(&rdev->nr_pending);
+ atomic_inc(&rdev->nr_pending);
+ rcu_read_unlock();
+ bi = bio_alloc(GFP_KERNEL, 0);
+ bi->bi_end_io = md_end_barrier;
+ bi->bi_private = rdev;
+ bi->bi_bdev = rdev->bdev;
+ atomic_inc(&mddev->flush_pending);
+ submit_bio(WRITE_BARRIER, bi);
+ rcu_read_lock();
+ rdev_dec_pending(rdev, mddev);
+ }
+ rcu_read_unlock();
+}
+
+static void md_submit_barrier(struct work_struct *ws)
+{
+ mddev_t *mddev = container_of(ws, mddev_t, barrier_work);
+ struct bio *bio = mddev->barrier;
+
+ atomic_set(&mddev->flush_pending, 1);
+
+ if (test_bit(BIO_EOPNOTSUPP, &bio->bi_flags))
+ bio_endio(bio, -EOPNOTSUPP);
+ else if (bio->bi_size == 0)
+ /* an empty barrier - all done */
+ bio_endio(bio, 0);
+ else {
+ bio->bi_rw &= ~(1<<BIO_RW_BARRIER);
+ if (mddev->pers->make_request(mddev->queue, bio))
+ generic_make_request(bio);
+ mddev->barrier = POST_REQUEST_BARRIER;
+ submit_barriers(mddev);
+ }
+ if (atomic_dec_and_test(&mddev->flush_pending)) {
+ mddev->barrier = NULL;
+ wake_up(&mddev->sb_wait);
+ }
+}
+
+void md_barrier_request(mddev_t *mddev, struct bio *bio)
+{
+ spin_lock_irq(&mddev->write_lock);
+ wait_event_lock_irq(mddev->sb_wait,
+ !mddev->barrier,
+ mddev->write_lock, /*nothing*/);
+ mddev->barrier = bio;
+ spin_unlock_irq(&mddev->write_lock);
+
+ atomic_set(&mddev->flush_pending, 1);
+ INIT_WORK(&mddev->barrier_work, md_submit_barrier);
+
+ submit_barriers(mddev);
+
+ if (atomic_dec_and_test(&mddev->flush_pending))
+ schedule_work(&mddev->barrier_work);
+}
+EXPORT_SYMBOL(md_barrier_request);
static inline mddev_t *mddev_get(mddev_t *mddev)
{
@@ -371,6 +471,7 @@ static mddev_t * mddev_find(dev_t unit)
atomic_set(&new->openers, 0);
atomic_set(&new->active_io, 0);
spin_lock_init(&new->write_lock);
+ atomic_set(&new->flush_pending, 0);
init_waitqueue_head(&new->sb_wait);
init_waitqueue_head(&new->recovery_wait);
new->reshape_position = MaxSector;
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 87430fea2875..cb036868a9e9 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -292,6 +292,17 @@ struct mddev_s
struct mutex bitmap_mutex;
struct list_head all_mddevs;
+
+ /* Generic barrier handling.
+ * If there is a pending barrier request, all other
+ * writes are blocked while the devices are flushed.
+ * The last to finish a flush schedules a worker to
+ * submit the barrier request (without the barrier flag),
+ * then submit more flush requests.
+ */
+ struct bio *barrier;
+ atomic_t flush_pending;
+ struct work_struct barrier_work;
};
@@ -432,6 +443,7 @@ extern void md_done_sync(mddev_t *mddev, int blocks, int ok);
extern void md_error(mddev_t *mddev, mdk_rdev_t *rdev);
extern int mddev_congested(mddev_t *mddev, int bits);
+extern void md_barrier_request(mddev_t *mddev, struct bio *bio);
extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
sector_t sector, int size, struct page *page);
extern void md_super_wait(mddev_t *mddev);
diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index ee7646f974a0..cbc0a99f3796 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -145,7 +145,7 @@ static int multipath_make_request (struct request_queue *q, struct bio * bio)
int cpu;
if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) {
- bio_endio(bio, -EOPNOTSUPP);
+ md_barrier_request(mddev, bio);
return 0;
}
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index d3a4ce06015a..122d07af5b54 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -453,7 +453,7 @@ static int raid0_make_request(struct request_queue *q, struct bio *bio)
int cpu;
if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) {
- bio_endio(bio, -EOPNOTSUPP);
+ md_barrier_request(mddev, bio);
return 0;
}
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index c2cb7b87b440..2fbf867f8b30 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -804,7 +804,7 @@ static int make_request(struct request_queue *q, struct bio * bio)
mdk_rdev_t *blocked_rdev;
if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) {
- bio_endio(bio, -EOPNOTSUPP);
+ md_barrier_request(mddev, bio);
return 0;
}
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 34cb065f6d66..8c9395f2028f 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -3865,7 +3865,13 @@ static int make_request(struct request_queue *q, struct bio * bi)
int cpu, remaining;
if (unlikely(bio_rw_flagged(bi, BIO_RW_BARRIER))) {
- bio_endio(bi, -EOPNOTSUPP);
+ /* Drain all pending writes. We only really need
+ * to ensure they have been submitted, but this is
+ * easier.
+ */
+ mddev->pers->quiesce(mddev, 1);
+ mddev->pers->quiesce(mddev, 0);
+ md_barrier_request(mddev, bi);
return 0;
}
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