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Subject[PATCH 015/118] drbd: Use interval tree for overlapping write request detection
Date
From: Andreas Gruenbacher <agruen@linbit.com>

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
drivers/block/drbd/drbd_int.h | 3 ++
drivers/block/drbd/drbd_main.c | 1 +
drivers/block/drbd/drbd_receiver.c | 38 +++++++++++-------------
drivers/block/drbd/drbd_req.c | 56 ++++++++++++++++++-----------------
drivers/block/drbd/drbd_req.h | 1 +
5 files changed, 52 insertions(+), 47 deletions(-)

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index d7678e8..0583713 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1019,6 +1019,9 @@ struct drbd_conf {
struct hlist_head *tl_hash;
unsigned int tl_hash_s;

+ /* Interval tree of pending local write requests */
+ struct rb_root write_requests;
+
/* blocks to resync in this run [unit BM_BLOCK_SIZE] */
unsigned long rs_total;
/* number of resync blocks that failed in this run */
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index a77b4bf..4d85838 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -3473,6 +3473,7 @@ struct drbd_conf *drbd_new_device(unsigned int minor)
/* no need to lock access, we are still initializing this minor device. */
if (!tl_init(mdev))
goto out_no_tl;
+ mdev->write_requests = RB_ROOT;

mdev->app_reads_hash = kzalloc(APP_R_HSIZE*sizeof(void *), GFP_KERNEL);
if (!mdev->app_reads_hash)
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 6bb1a2f..6b072584 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -1733,9 +1733,6 @@ static int receive_Data(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned
const int size = e->size;
const int discard = test_bit(DISCARD_CONCURRENT, &mdev->flags);
DEFINE_WAIT(wait);
- struct drbd_request *i;
- struct hlist_node *n;
- struct hlist_head *slot;
int first;

D_ASSERT(mdev->net_conf->wire_protocol == DRBD_PROT_C);
@@ -1783,30 +1780,31 @@ static int receive_Data(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned

hlist_add_head(&e->collision, ee_hash_slot(mdev, sector));

-#define OVERLAPS overlaps(i->i.sector, i->i.size, sector, size)
- slot = tl_hash_slot(mdev, sector);
first = 1;
for (;;) {
+ struct drbd_interval *i;
int have_unacked = 0;
int have_conflict = 0;
prepare_to_wait(&mdev->misc_wait, &wait,
TASK_INTERRUPTIBLE);
- hlist_for_each_entry(i, n, slot, collision) {
- if (OVERLAPS) {
- /* only ALERT on first iteration,
- * we may be woken up early... */
- if (first)
- dev_alert(DEV, "%s[%u] Concurrent local write detected!"
- " new: %llus +%u; pending: %llus +%u\n",
- current->comm, current->pid,
- (unsigned long long)sector, size,
- (unsigned long long)i->i.sector, i->i.size);
- if (i->rq_state & RQ_NET_PENDING)
- ++have_unacked;
- ++have_conflict;
- }
+
+ i = drbd_find_overlap(&mdev->write_requests, sector, size);
+ if (i) {
+ struct drbd_request *req2 =
+ container_of(i, struct drbd_request, i);
+
+ /* only ALERT on first iteration,
+ * we may be woken up early... */
+ if (first)
+ dev_alert(DEV, "%s[%u] Concurrent local write detected!"
+ " new: %llus +%u; pending: %llus +%u\n",
+ current->comm, current->pid,
+ (unsigned long long)sector, size,
+ (unsigned long long)req2->i.sector, req2->i.size);
+ if (req2->rq_state & RQ_NET_PENDING)
+ ++have_unacked;
+ ++have_conflict;
}
-#undef OVERLAPS
if (!have_conflict)
break;

diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 1af11a1..593576f 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -135,7 +135,6 @@ static void _about_to_complete_local_write(struct drbd_conf *mdev,
struct drbd_request *req)
{
const unsigned long s = req->rq_state;
- struct drbd_request *i;
struct drbd_epoch_entry *e;
struct hlist_node *n;
struct hlist_head *slot;
@@ -157,19 +156,21 @@ static void _about_to_complete_local_write(struct drbd_conf *mdev,
if ((s & RQ_NET_DONE) && mdev->ee_hash != NULL) {
const sector_t sector = req->i.sector;
const int size = req->i.size;
+ struct drbd_interval *i;

/* ASSERT:
* there must be no conflicting requests, since
* they must have been failed on the spot */
-#define OVERLAPS overlaps(sector, size, i->i.sector, i->i.size)
- slot = tl_hash_slot(mdev, sector);
- hlist_for_each_entry(i, n, slot, collision) {
- if (OVERLAPS) {
- dev_alert(DEV, "LOGIC BUG: completed: %p %llus +%u; "
- "other: %p %llus +%u\n",
- req, (unsigned long long)sector, size,
- i, (unsigned long long)i->i.sector, i->i.size);
- }
+
+ i = drbd_find_overlap(&mdev->write_requests, sector, size);
+ if (i) {
+ struct drbd_request *req2 =
+ container_of(i, struct drbd_request, i);
+
+ dev_alert(DEV, "LOGIC BUG: completed: %p %llus +%u; "
+ "other: %p %llus +%u\n",
+ req, (unsigned long long)sector, size,
+ i, (unsigned long long)req2->i.sector, req2->i.size);
}

/* maybe "wake" those conflicting epoch entries
@@ -184,7 +185,6 @@ static void _about_to_complete_local_write(struct drbd_conf *mdev,
*
* anyways, if we found one,
* we just have to do a wake_up. */
-#undef OVERLAPS
#define OVERLAPS overlaps(sector, size, e->sector, e->size)
slot = ee_hash_slot(mdev, req->i.sector);
hlist_for_each_entry(e, n, slot, collision) {
@@ -260,9 +260,11 @@ void _req_may_be_done(struct drbd_request *req, struct bio_and_error *m)

/* remove the request from the conflict detection
* respective block_id verification hash */
- if (!hlist_unhashed(&req->collision))
+ if (!hlist_unhashed(&req->collision)) {
hlist_del(&req->collision);
- else
+ if (!drbd_interval_empty(&req->i))
+ drbd_remove_interval(&mdev->write_requests, &req->i);
+ } else
D_ASSERT((s & (RQ_NET_MASK & ~RQ_NET_DONE)) == 0);

/* for writes we need to do some extra housekeeping */
@@ -324,7 +326,7 @@ static int _req_conflicts(struct drbd_request *req)
struct drbd_conf *mdev = req->mdev;
const sector_t sector = req->i.sector;
const int size = req->i.size;
- struct drbd_request *i;
+ struct drbd_interval *i;
struct drbd_epoch_entry *e;
struct hlist_node *n;
struct hlist_head *slot;
@@ -339,24 +341,23 @@ static int _req_conflicts(struct drbd_request *req)
goto out_no_conflict;
BUG_ON(mdev->tl_hash == NULL);

-#define OVERLAPS overlaps(i->i.sector, i->i.size, sector, size)
- slot = tl_hash_slot(mdev, sector);
- hlist_for_each_entry(i, n, slot, collision) {
- if (OVERLAPS) {
- dev_alert(DEV, "%s[%u] Concurrent local write detected! "
- "[DISCARD L] new: %llus +%u; "
- "pending: %llus +%u\n",
- current->comm, current->pid,
- (unsigned long long)sector, size,
- (unsigned long long)i->i.sector, i->i.size);
- goto out_conflict;
- }
+ i = drbd_find_overlap(&mdev->write_requests, sector, size);
+ if (i) {
+ struct drbd_request *req2 =
+ container_of(i, struct drbd_request, i);
+
+ dev_alert(DEV, "%s[%u] Concurrent local write detected! "
+ "[DISCARD L] new: %llus +%u; "
+ "pending: %llus +%u\n",
+ current->comm, current->pid,
+ (unsigned long long)sector, size,
+ (unsigned long long)req2->i.sector, req2->i.size);
+ goto out_conflict;
}

if (mdev->ee_hash_s) {
/* now, check for overlapping requests with remote origin */
BUG_ON(mdev->ee_hash == NULL);
-#undef OVERLAPS
#define OVERLAPS overlaps(e->sector, e->size, sector, size)
slot = ee_hash_slot(mdev, sector);
hlist_for_each_entry(e, n, slot, collision) {
@@ -509,6 +510,7 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,

hlist_add_head(&req->collision, tl_hash_slot(mdev, req->i.sector));
/* corresponding hlist_del is in _req_may_be_done() */
+ drbd_insert_interval(&mdev->write_requests, &req->i);

/* NOTE
* In case the req ended up on the transfer log before being
diff --git a/drivers/block/drbd/drbd_req.h b/drivers/block/drbd/drbd_req.h
index 2520186..6f11624 100644
--- a/drivers/block/drbd/drbd_req.h
+++ b/drivers/block/drbd/drbd_req.h
@@ -275,6 +275,7 @@ static inline struct drbd_request *drbd_req_new(struct drbd_conf *mdev,
req->i.sector = bio_src->bi_sector;
req->i.size = bio_src->bi_size;
INIT_HLIST_NODE(&req->collision);
+ drbd_clear_interval(&req->i);
INIT_LIST_HEAD(&req->tl_requests);
INIT_LIST_HEAD(&req->w.list);
}
--
1.7.4.1


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