Merge branch 'for-4.8/drivers' of git://git.kernel.dk/linux-block

Pull block driver updates from Jens Axboe:
 "This branch also contains core changes.  I've come to the conclusion
  that from 4.9 and forward, I'll be doing just a single branch.  We
  often have dependencies between core and drivers, and it's hard to
  always split them up appropriately without pulling core into drivers
  when that happens.

  That said, this contains:

   - separate secure erase type for the core block layer, from
     Christoph.

   - set of discard fixes, from Christoph.

   - bio shrinking fixes from Christoph, as a followup up to the
     op/flags change in the core branch.

   - map and append request fixes from Christoph.

   - NVMeF (NVMe over Fabrics) code from Christoph.  This is pretty
     exciting!

   - nvme-loop fixes from Arnd.

   - removal of ->driverfs_dev from Dan, after providing a
     device_add_disk() helper.

   - bcache fixes from Bhaktipriya and Yijing.

   - cdrom subchannel read fix from Vchannaiah.

   - set of lightnvm updates from Wenwei, Matias, Johannes, and Javier.

   - set of drbd updates and fixes from Fabian, Lars, and Philipp.

   - mg_disk error path fix from Bart.

   - user notification for failed device add for loop, from Minfei.

   - NVMe in general:
        + NVMe delay quirk from Guilherme.
        + SR-IOV support and command retry limits from Keith.
        + fix for memory-less NUMA node from Masayoshi.
        + use UINT_MAX for discard sectors, from Minfei.
        + cancel IO fixes from Ming.
        + don't allocate unused major, from Neil.
        + error code fixup from Dan.
        + use constants for PSDT/FUSE from James.
        + variable init fix from Jay.
        + fabrics fixes from Ming, Sagi, and Wei.
        + various fixes"

* 'for-4.8/drivers' of git://git.kernel.dk/linux-block: (115 commits)
  nvme/pci: Provide SR-IOV support
  nvme: initialize variable before logical OR'ing it
  block: unexport various bio mapping helpers
  scsi/osd: open code blk_make_request
  target: stop using blk_make_request
  block: simplify and export blk_rq_append_bio
  block: ensure bios return from blk_get_request are properly initialized
  virtio_blk: use blk_rq_map_kern
  memstick: don't allow REQ_TYPE_BLOCK_PC requests
  block: shrink bio size again
  block: simplify and cleanup bvec pool handling
  block: get rid of bio_rw and READA
  block: don't ignore -EOPNOTSUPP blkdev_issue_write_same
  block: introduce BLKDEV_DISCARD_ZERO to fix zeroout
  NVMe: don't allocate unused nvme_major
  nvme: avoid crashes when node 0 is memoryless node.
  nvme: Limit command retries
  loop: Make user notify for adding loop device failed
  nvme-loop: fix nvme-loop Kconfig dependencies
  nvmet: fix return value check in nvmet_subsys_alloc()
  ...

1 files changed, 444 insertions, 91 deletions

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 1ee002352ea2..df45713dfbe8 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -25,7 +25,7 @@
 
 #include <linux/module.h>
 
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
 #include <net/sock.h>
 
 #include <linux/drbd.h>
@@ -48,7 +48,7 @@
 #include "drbd_req.h"
 #include "drbd_vli.h"
 
-#define PRO_FEATURES (FF_TRIM)
+#define PRO_FEATURES (DRBD_FF_TRIM|DRBD_FF_THIN_RESYNC|DRBD_FF_WSAME)
 
 struct packet_info {
 	enum drbd_packet cmd;
@@ -361,14 +361,17 @@ You must not have the req_lock:
  drbd_wait_ee_list_empty()
 */
 
+/* normal: payload_size == request size (bi_size)
+ * w_same: payload_size == logical_block_size
+ * trim: payload_size == 0 */
 struct drbd_peer_request *
 drbd_alloc_peer_req(struct drbd_peer_device *peer_device, u64 id, sector_t sector,
-		    unsigned int data_size, bool has_payload, gfp_t gfp_mask) __must_hold(local)
+		    unsigned int request_size, unsigned int payload_size, gfp_t gfp_mask) __must_hold(local)
 {
 	struct drbd_device *device = peer_device->device;
 	struct drbd_peer_request *peer_req;
 	struct page *page = NULL;
-	unsigned nr_pages = (data_size + PAGE_SIZE -1) >> PAGE_SHIFT;
+	unsigned nr_pages = (payload_size + PAGE_SIZE -1) >> PAGE_SHIFT;
 
 	if (drbd_insert_fault(device, DRBD_FAULT_AL_EE))
 		return NULL;
@@ -380,7 +383,7 @@ drbd_alloc_peer_req(struct drbd_peer_device *peer_device, u64 id, sector_t secto
 		return NULL;
 	}
 
-	if (has_payload && data_size) {
+	if (nr_pages) {
 		page = drbd_alloc_pages(peer_device, nr_pages,
 					gfpflags_allow_blocking(gfp_mask));
 		if (!page)
@@ -390,7 +393,7 @@ drbd_alloc_peer_req(struct drbd_peer_device *peer_device, u64 id, sector_t secto
 	memset(peer_req, 0, sizeof(*peer_req));
 	INIT_LIST_HEAD(&peer_req->w.list);
 	drbd_clear_interval(&peer_req->i);
-	peer_req->i.size = data_size;
+	peer_req->i.size = request_size;
 	peer_req->i.sector = sector;
 	peer_req->submit_jif = jiffies;
 	peer_req->peer_device = peer_device;
@@ -1204,13 +1207,84 @@ static int drbd_recv_header(struct drbd_connection *connection, struct packet_in
 	return err;
 }
 
-static void drbd_flush(struct drbd_connection *connection)
+/* This is blkdev_issue_flush, but asynchronous.
+ * We want to submit to all component volumes in parallel,
+ * then wait for all completions.
+ */
+struct issue_flush_context {
+	atomic_t pending;
+	int error;
+	struct completion done;
+};
+struct one_flush_context {
+	struct drbd_device *device;
+	struct issue_flush_context *ctx;
+};
+
+void one_flush_endio(struct bio *bio)
 {
-	int rv;
-	struct drbd_peer_device *peer_device;
-	int vnr;
+	struct one_flush_context *octx = bio->bi_private;
+	struct drbd_device *device = octx->device;
+	struct issue_flush_context *ctx = octx->ctx;
 
+	if (bio->bi_error) {
+		ctx->error = bio->bi_error;
+		drbd_info(device, "local disk FLUSH FAILED with status %d\n", bio->bi_error);
+	}
+	kfree(octx);
+	bio_put(bio);
+
+	clear_bit(FLUSH_PENDING, &device->flags);
+	put_ldev(device);
+	kref_put(&device->kref, drbd_destroy_device);
+
+	if (atomic_dec_and_test(&ctx->pending))
+		complete(&ctx->done);
+}
+
+static void submit_one_flush(struct drbd_device *device, struct issue_flush_context *ctx)
+{
+	struct bio *bio = bio_alloc(GFP_NOIO, 0);
+	struct one_flush_context *octx = kmalloc(sizeof(*octx), GFP_NOIO);
+	if (!bio || !octx) {
+		drbd_warn(device, "Could not allocate a bio, CANNOT ISSUE FLUSH\n");
+		/* FIXME: what else can I do now?  disconnecting or detaching
+		 * really does not help to improve the state of the world, either.
+		 */
+		kfree(octx);
+		if (bio)
+			bio_put(bio);
+
+		ctx->error = -ENOMEM;
+		put_ldev(device);
+		kref_put(&device->kref, drbd_destroy_device);
+		return;
+	}
+
+	octx->device = device;
+	octx->ctx = ctx;
+	bio->bi_bdev = device->ldev->backing_bdev;
+	bio->bi_private = octx;
+	bio->bi_end_io = one_flush_endio;
+	bio_set_op_attrs(bio, REQ_OP_FLUSH, WRITE_FLUSH);
+
+	device->flush_jif = jiffies;
+	set_bit(FLUSH_PENDING, &device->flags);
+	atomic_inc(&ctx->pending);
+	submit_bio(bio);
+}
+
+static void drbd_flush(struct drbd_connection *connection)
+{
 	if (connection->resource->write_ordering >= WO_BDEV_FLUSH) {
+		struct drbd_peer_device *peer_device;
+		struct issue_flush_context ctx;
+		int vnr;
+
+		atomic_set(&ctx.pending, 1);
+		ctx.error = 0;
+		init_completion(&ctx.done);
+
 		rcu_read_lock();
 		idr_for_each_entry(&connection->peer_devices, peer_device, vnr) {
 			struct drbd_device *device = peer_device->device;
@@ -1220,31 +1294,24 @@ static void drbd_flush(struct drbd_connection *connection)
 			kref_get(&device->kref);
 			rcu_read_unlock();
 
-			/* Right now, we have only this one synchronous code path
-			 * for flushes between request epochs.
-			 * We may want to make those asynchronous,
-			 * or at least parallelize the flushes to the volume devices.
-			 */
-			device->flush_jif = jiffies;
-			set_bit(FLUSH_PENDING, &device->flags);
-			rv = blkdev_issue_flush(device->ldev->backing_bdev,
-					GFP_NOIO, NULL);
-			clear_bit(FLUSH_PENDING, &device->flags);
-			if (rv) {
-				drbd_info(device, "local disk flush failed with status %d\n", rv);
-				/* would rather check on EOPNOTSUPP, but that is not reliable.
-				 * don't try again for ANY return value != 0
-				 * if (rv == -EOPNOTSUPP) */
-				drbd_bump_write_ordering(connection->resource, NULL, WO_DRAIN_IO);
-			}
-			put_ldev(device);
-			kref_put(&device->kref, drbd_destroy_device);
+			submit_one_flush(device, &ctx);
 
 			rcu_read_lock();
-			if (rv)
-				break;
 		}
 		rcu_read_unlock();
+
+		/* Do we want to add a timeout,
+		 * if disk-timeout is set? */
+		if (!atomic_dec_and_test(&ctx.pending))
+			wait_for_completion(&ctx.done);
+
+		if (ctx.error) {
+			/* would rather check on EOPNOTSUPP, but that is not reliable.
+			 * don't try again for ANY return value != 0
+			 * if (rv == -EOPNOTSUPP) */
+			/* Any error is already reported by bio_endio callback. */
+			drbd_bump_write_ordering(connection->resource, NULL, WO_DRAIN_IO);
+		}
 	}
 }
 
@@ -1379,6 +1446,120 @@ void drbd_bump_write_ordering(struct drbd_resource *resource, struct drbd_backin
 		drbd_info(resource, "Method to ensure write ordering: %s\n", write_ordering_str[resource->write_ordering]);
 }
 
+/*
+ * We *may* ignore the discard-zeroes-data setting, if so configured.
+ *
+ * Assumption is that it "discard_zeroes_data=0" is only because the backend
+ * may ignore partial unaligned discards.
+ *
+ * LVM/DM thin as of at least
+ *   LVM version:     2.02.115(2)-RHEL7 (2015-01-28)
+ *   Library version: 1.02.93-RHEL7 (2015-01-28)
+ *   Driver version:  4.29.0
+ * still behaves this way.
+ *
+ * For unaligned (wrt. alignment and granularity) or too small discards,
+ * we zero-out the initial (and/or) trailing unaligned partial chunks,
+ * but discard all the aligned full chunks.
+ *
+ * At least for LVM/DM thin, the result is effectively "discard_zeroes_data=1".
+ */
+int drbd_issue_discard_or_zero_out(struct drbd_device *device, sector_t start, unsigned int nr_sectors, bool discard)
+{
+	struct block_device *bdev = device->ldev->backing_bdev;
+	struct request_queue *q = bdev_get_queue(bdev);
+	sector_t tmp, nr;
+	unsigned int max_discard_sectors, granularity;
+	int alignment;
+	int err = 0;
+
+	if (!discard)
+		goto zero_out;
+
+	/* Zero-sector (unknown) and one-sector granularities are the same.  */
+	granularity = max(q->limits.discard_granularity >> 9, 1U);
+	alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;
+
+	max_discard_sectors = min(q->limits.max_discard_sectors, (1U << 22));
+	max_discard_sectors -= max_discard_sectors % granularity;
+	if (unlikely(!max_discard_sectors))
+		goto zero_out;
+
+	if (nr_sectors < granularity)
+		goto zero_out;
+
+	tmp = start;
+	if (sector_div(tmp, granularity) != alignment) {
+		if (nr_sectors < 2*granularity)
+			goto zero_out;
+		/* start + gran - (start + gran - align) % gran */
+		tmp = start + granularity - alignment;
+		tmp = start + granularity - sector_div(tmp, granularity);
+
+		nr = tmp - start;
+		err |= blkdev_issue_zeroout(bdev, start, nr, GFP_NOIO, 0);
+		nr_sectors -= nr;
+		start = tmp;
+	}
+	while (nr_sectors >= granularity) {
+		nr = min_t(sector_t, nr_sectors, max_discard_sectors);
+		err |= blkdev_issue_discard(bdev, start, nr, GFP_NOIO, 0);
+		nr_sectors -= nr;
+		start += nr;
+	}
+ zero_out:
+	if (nr_sectors) {
+		err |= blkdev_issue_zeroout(bdev, start, nr_sectors, GFP_NOIO, 0);
+	}
+	return err != 0;
+}
+
+static bool can_do_reliable_discards(struct drbd_device *device)
+{
+	struct request_queue *q = bdev_get_queue(device->ldev->backing_bdev);
+	struct disk_conf *dc;
+	bool can_do;
+
+	if (!blk_queue_discard(q))
+		return false;
+
+	if (q->limits.discard_zeroes_data)
+		return true;
+
+	rcu_read_lock();
+	dc = rcu_dereference(device->ldev->disk_conf);
+	can_do = dc->discard_zeroes_if_aligned;
+	rcu_read_unlock();
+	return can_do;
+}
+
+static void drbd_issue_peer_discard(struct drbd_device *device, struct drbd_peer_request *peer_req)
+{
+	/* If the backend cannot discard, or does not guarantee
+	 * read-back zeroes in discarded ranges, we fall back to
+	 * zero-out.  Unless configuration specifically requested
+	 * otherwise. */
+	if (!can_do_reliable_discards(device))
+		peer_req->flags |= EE_IS_TRIM_USE_ZEROOUT;
+
+	if (drbd_issue_discard_or_zero_out(device, peer_req->i.sector,
+	    peer_req->i.size >> 9, !(peer_req->flags & EE_IS_TRIM_USE_ZEROOUT)))
+		peer_req->flags |= EE_WAS_ERROR;
+	drbd_endio_write_sec_final(peer_req);
+}
+
+static void drbd_issue_peer_wsame(struct drbd_device *device,
+				  struct drbd_peer_request *peer_req)
+{
+	struct block_device *bdev = device->ldev->backing_bdev;
+	sector_t s = peer_req->i.sector;
+	sector_t nr = peer_req->i.size >> 9;
+	if (blkdev_issue_write_same(bdev, s, nr, GFP_NOIO, peer_req->pages))
+		peer_req->flags |= EE_WAS_ERROR;
+	drbd_endio_write_sec_final(peer_req);
+}
+
+
 /**
  * drbd_submit_peer_request()
  * @device:	DRBD device.
@@ -1410,7 +1591,13 @@ int drbd_submit_peer_request(struct drbd_device *device,
 	unsigned nr_pages = (data_size + PAGE_SIZE -1) >> PAGE_SHIFT;
 	int err = -ENOMEM;
 
-	if (peer_req->flags & EE_IS_TRIM_USE_ZEROOUT) {
+	/* TRIM/DISCARD: for now, always use the helper function
+	 * blkdev_issue_zeroout(..., discard=true).
+	 * It's synchronous, but it does the right thing wrt. bio splitting.
+	 * Correctness first, performance later.  Next step is to code an
+	 * asynchronous variant of the same.
+	 */
+	if (peer_req->flags & (EE_IS_TRIM|EE_WRITE_SAME)) {
 		/* wait for all pending IO completions, before we start
 		 * zeroing things out. */
 		conn_wait_active_ee_empty(peer_req->peer_device->connection);
@@ -1418,22 +1605,22 @@ int drbd_submit_peer_request(struct drbd_device *device,
 		 * so we can find it to present it in debugfs */
 		peer_req->submit_jif = jiffies;
 		peer_req->flags |= EE_SUBMITTED;
-		spin_lock_irq(&device->resource->req_lock);
-		list_add_tail(&peer_req->w.list, &device->active_ee);
-		spin_unlock_irq(&device->resource->req_lock);
-		if (blkdev_issue_zeroout(device->ldev->backing_bdev,
-			sector, data_size >> 9, GFP_NOIO, false))
-			peer_req->flags |= EE_WAS_ERROR;
-		drbd_endio_write_sec_final(peer_req);
+
+		/* If this was a resync request from receive_rs_deallocated(),
+		 * it is already on the sync_ee list */
+		if (list_empty(&peer_req->w.list)) {
+			spin_lock_irq(&device->resource->req_lock);
+			list_add_tail(&peer_req->w.list, &device->active_ee);
+			spin_unlock_irq(&device->resource->req_lock);
+		}
+
+		if (peer_req->flags & EE_IS_TRIM)
+			drbd_issue_peer_discard(device, peer_req);
+		else /* EE_WRITE_SAME */
+			drbd_issue_peer_wsame(device, peer_req);
 		return 0;
 	}
 
-	/* Discards don't have any payload.
-	 * But the scsi layer still expects a bio_vec it can use internally,
-	 * see sd_setup_discard_cmnd() and blk_add_request_payload(). */
-	if (peer_req->flags & EE_IS_TRIM)
-		nr_pages = 1;
-
 	/* In most cases, we will only need one bio.  But in case the lower
 	 * level restrictions happen to be different at this offset on this
 	 * side than those of the sending peer, we may need to submit the
@@ -1459,11 +1646,6 @@ next_bio:
 	bios = bio;
 	++n_bios;
 
-	if (op == REQ_OP_DISCARD) {
-		bio->bi_iter.bi_size = data_size;
-		goto submit;
-	}
-
 	page_chain_for_each(page) {
 		unsigned len = min_t(unsigned, data_size, PAGE_SIZE);
 		if (!bio_add_page(bio, page, len, 0)) {
@@ -1485,7 +1667,6 @@ next_bio:
 		--nr_pages;
 	}
 	D_ASSERT(device, data_size == 0);
-submit:
 	D_ASSERT(device, page == NULL);
 
 	atomic_set(&peer_req->pending_bios, n_bios);
@@ -1609,8 +1790,26 @@ static int receive_Barrier(struct drbd_connection *connection, struct packet_inf
 	return 0;
 }
 
+/* quick wrapper in case payload size != request_size (write same) */
+static void drbd_csum_ee_size(struct crypto_ahash *h,
+			      struct drbd_peer_request *r, void *d,
+			      unsigned int payload_size)
+{
+	unsigned int tmp = r->i.size;
+	r->i.size = payload_size;
+	drbd_csum_ee(h, r, d);
+	r->i.size = tmp;
+}
+
 /* used from receive_RSDataReply (recv_resync_read)
- * and from receive_Data */
+ * and from receive_Data.
+ * data_size: actual payload ("data in")
+ * 	for normal writes that is bi_size.
+ * 	for discards, that is zero.
+ * 	for write same, it is logical_block_size.
+ * both trim and write same have the bi_size ("data len to be affected")
+ * as extra argument in the packet header.
+ */
 static struct drbd_peer_request *
 read_in_block(struct drbd_peer_device *peer_device, u64 id, sector_t sector,
 	      struct packet_info *pi) __must_hold(local)
@@ -1625,6 +1824,7 @@ read_in_block(struct drbd_peer_device *peer_device, u64 id, sector_t sector,
 	void *dig_vv = peer_device->connection->int_dig_vv;
 	unsigned long *data;
 	struct p_trim *trim = (pi->cmd == P_TRIM) ? pi->data : NULL;
+	struct p_trim *wsame = (pi->cmd == P_WSAME) ? pi->data : NULL;
 
 	digest_size = 0;
 	if (!trim && peer_device->connection->peer_integrity_tfm) {
@@ -1639,38 +1839,60 @@ read_in_block(struct drbd_peer_device *peer_device, u64 id, sector_t sector,
 		data_size -= digest_size;
 	}
 
+	/* assume request_size == data_size, but special case trim and wsame. */
+	ds = data_size;
 	if (trim) {
-		D_ASSERT(peer_device, data_size == 0);
-		data_size = be32_to_cpu(trim->size);
+		if (!expect(data_size == 0))
+			return NULL;
+		ds = be32_to_cpu(trim->size);
+	} else if (wsame) {
+		if (data_size != queue_logical_block_size(device->rq_queue)) {
+			drbd_err(peer_device, "data size (%u) != drbd logical block size (%u)\n",
+				data_size, queue_logical_block_size(device->rq_queue));
+			return NULL;
+		}
+		if (data_size != bdev_logical_block_size(device->ldev->backing_bdev)) {
+			drbd_err(peer_device, "data size (%u) != backend logical block size (%u)\n",
+				data_size, bdev_logical_block_size(device->ldev->backing_bdev));
+			return NULL;
+		}
+		ds = be32_to_cpu(wsame->size);
 	}
 
-	if (!expect(IS_ALIGNED(data_size, 512)))
+	if (!expect(IS_ALIGNED(ds, 512)))
 		return NULL;
-	/* prepare for larger trim requests. */
-	if (!trim && !expect(data_size <= DRBD_MAX_BIO_SIZE))
+	if (trim || wsame) {
+		if (!expect(ds <= (DRBD_MAX_BBIO_SECTORS << 9)))
+			return NULL;
+	} else if (!expect(ds <= DRBD_MAX_BIO_SIZE))
 		return NULL;
 
 	/* even though we trust out peer,
 	 * we sometimes have to double check. */
-	if (sector + (data_size>>9) > capacity) {
+	if (sector + (ds>>9) > capacity) {
 		drbd_err(device, "request from peer beyond end of local disk: "
 			"capacity: %llus < sector: %llus + size: %u\n",
 			(unsigned long long)capacity,
-			(unsigned long long)sector, data_size);
+			(unsigned long long)sector, ds);
 		return NULL;
 	}
 
 	/* GFP_NOIO, because we must not cause arbitrary write-out: in a DRBD
 	 * "criss-cross" setup, that might cause write-out on some other DRBD,
 	 * which in turn might block on the other node at this very place.  */
-	peer_req = drbd_alloc_peer_req(peer_device, id, sector, data_size, trim == NULL, GFP_NOIO);
+	peer_req = drbd_alloc_peer_req(peer_device, id, sector, ds, data_size, GFP_NOIO);
 	if (!peer_req)
 		return NULL;
 
 	peer_req->flags |= EE_WRITE;
-	if (trim)
+	if (trim) {
+		peer_req->flags |= EE_IS_TRIM;
 		return peer_req;
+	}
+	if (wsame)
+		peer_req->flags |= EE_WRITE_SAME;
 
+	/* receive payload size bytes into page chain */
 	ds = data_size;
 	page = peer_req->pages;
 	page_chain_for_each(page) {
@@ -1690,7 +1912,7 @@ read_in_block(struct drbd_peer_device *peer_device, u64 id, sector_t sector,
 	}
 
 	if (digest_size) {
-		drbd_csum_ee(peer_device->connection->peer_integrity_tfm, peer_req, dig_vv);
+		drbd_csum_ee_size(peer_device->connection->peer_integrity_tfm, peer_req, dig_vv, data_size);
 		if (memcmp(dig_in, dig_vv, digest_size)) {
 			drbd_err(device, "Digest integrity check FAILED: %llus +%u\n",
 				(unsigned long long)sector, data_size);
@@ -2067,13 +2289,13 @@ static inline int overlaps(sector_t s1, int l1, sector_t s2, int l2)
 static bool overlapping_resync_write(struct drbd_device *device, struct drbd_peer_request *peer_req)
 {
 	struct drbd_peer_request *rs_req;
-	bool rv = 0;
+	bool rv = false;
 
 	spin_lock_irq(&device->resource->req_lock);
 	list_for_each_entry(rs_req, &device->sync_ee, w.list) {
 		if (overlaps(peer_req->i.sector, peer_req->i.size,
 			     rs_req->i.sector, rs_req->i.size)) {
-			rv = 1;
+			rv = true;
 			break;
 		}
 	}
@@ -2354,10 +2576,6 @@ static int receive_Data(struct drbd_connection *connection, struct packet_info *
 	op = wire_flags_to_bio_op(dp_flags);
 	op_flags = wire_flags_to_bio_flags(dp_flags);
 	if (pi->cmd == P_TRIM) {
-		struct request_queue *q = bdev_get_queue(device->ldev->backing_bdev);
-		peer_req->flags |= EE_IS_TRIM;
-		if (!blk_queue_discard(q))
-			peer_req->flags |= EE_IS_TRIM_USE_ZEROOUT;
 		D_ASSERT(peer_device, peer_req->i.size > 0);
 		D_ASSERT(peer_device, op == REQ_OP_DISCARD);
 		D_ASSERT(peer_device, peer_req->pages == NULL);
@@ -2424,11 +2642,11 @@ static int receive_Data(struct drbd_connection *connection, struct packet_info *
 		update_peer_seq(peer_device, peer_seq);
 		spin_lock_irq(&device->resource->req_lock);
 	}
-	/* if we use the zeroout fallback code, we process synchronously
-	 * and we wait for all pending requests, respectively wait for
+	/* TRIM and WRITE_SAME are processed synchronously,
+	 * we wait for all pending requests, respectively wait for
 	 * active_ee to become empty in drbd_submit_peer_request();
 	 * better not add ourselves here. */
-	if ((peer_req->flags & EE_IS_TRIM_USE_ZEROOUT) == 0)
+	if ((peer_req->flags & (EE_IS_TRIM|EE_WRITE_SAME)) == 0)
 		list_add_tail(&peer_req->w.list, &device->active_ee);
 	spin_unlock_irq(&device->resource->req_lock);
 
@@ -2460,7 +2678,7 @@ static int receive_Data(struct drbd_connection *connection, struct packet_info *
 	}
 
 out_interrupted:
-	drbd_may_finish_epoch(connection, peer_req->epoch, EV_PUT + EV_CLEANUP);
+	drbd_may_finish_epoch(connection, peer_req->epoch, EV_PUT | EV_CLEANUP);
 	put_ldev(device);
 	drbd_free_peer_req(device, peer_req);
 	return err;
@@ -2585,6 +2803,7 @@ static int receive_DataRequest(struct drbd_connection *connection, struct packet
 		case P_DATA_REQUEST:
 			drbd_send_ack_rp(peer_device, P_NEG_DREPLY, p);
 			break;
+		case P_RS_THIN_REQ:
 		case P_RS_DATA_REQUEST:
 		case P_CSUM_RS_REQUEST:
 		case P_OV_REQUEST:
@@ -2610,7 +2829,7 @@ static int receive_DataRequest(struct drbd_connection *connection, struct packet
 	 * "criss-cross" setup, that might cause write-out on some other DRBD,
 	 * which in turn might block on the other node at this very place.  */
 	peer_req = drbd_alloc_peer_req(peer_device, p->block_id, sector, size,
-			true /* has real payload */, GFP_NOIO);
+			size, GFP_NOIO);
 	if (!peer_req) {
 		put_ldev(device);
 		return -ENOMEM;
@@ -2624,6 +2843,12 @@ static int receive_DataRequest(struct drbd_connection *connection, struct packet
 		peer_req->flags |= EE_APPLICATION;
 		goto submit;
 
+	case P_RS_THIN_REQ:
+		/* If at some point in the future we have a smart way to
+		   find out if this data block is completely deallocated,
+		   then we would do something smarter here than reading
+		   the block... */
+		peer_req->flags |= EE_RS_THIN_REQ;
 	case P_RS_DATA_REQUEST:
 		peer_req->w.cb = w_e_end_rsdata_req;
 		fault_type = DRBD_FAULT_RS_RD;
@@ -2969,7 +3194,8 @@ static void drbd_uuid_dump(struct drbd_device *device, char *text, u64 *uuid,
 -1091   requires proto 91
 -1096   requires proto 96
  */
-static int drbd_uuid_compare(struct drbd_device *const device, int *rule_nr) __must_hold(local)
+
+static int drbd_uuid_compare(struct drbd_device *const device, enum drbd_role const peer_role, int *rule_nr) __must_hold(local)
 {
 	struct drbd_peer_device *const peer_device = first_peer_device(device);
 	struct drbd_connection *const connection = peer_device ? peer_device->connection : NULL;
@@ -3049,8 +3275,39 @@ static int drbd_uuid_compare(struct drbd_device *const device, int *rule_nr) __m
 		 * next bit (weight 2) is set when peer was primary */
 		*rule_nr = 40;
 
+		/* Neither has the "crashed primary" flag set,
+		 * only a replication link hickup. */
+		if (rct == 0)
+			return 0;
+
+		/* Current UUID equal and no bitmap uuid; does not necessarily
+		 * mean this was a "simultaneous hard crash", maybe IO was
+		 * frozen, so no UUID-bump happened.
+		 * This is a protocol change, overload DRBD_FF_WSAME as flag
+		 * for "new-enough" peer DRBD version. */
+		if (device->state.role == R_PRIMARY || peer_role == R_PRIMARY) {
+			*rule_nr = 41;
+			if (!(connection->agreed_features & DRBD_FF_WSAME)) {
+				drbd_warn(peer_device, "Equivalent unrotated UUIDs, but current primary present.\n");
+				return -(0x10000 | PRO_VERSION_MAX | (DRBD_FF_WSAME << 8));
+			}
+			if (device->state.role == R_PRIMARY && peer_role == R_PRIMARY) {
+				/* At least one has the "crashed primary" bit set,
+				 * both are primary now, but neither has rotated its UUIDs?
+				 * "Can not happen." */
+				drbd_err(peer_device, "Equivalent unrotated UUIDs, but both are primary. Can not resolve this.\n");
+				return -100;
+			}
+			if (device->state.role == R_PRIMARY)
+				return 1;
+			return -1;
+		}
+
+		/* Both are secondary.
+		 * Really looks like recovery from simultaneous hard crash.
+		 * Check which had been primary before, and arbitrate. */
 		switch (rct) {
-		case 0: /* !self_pri && !peer_pri */ return 0;
+		case 0: /* !self_pri && !peer_pri */ return 0; /* already handled */
 		case 1: /*  self_pri && !peer_pri */ return 1;
 		case 2: /* !self_pri &&  peer_pri */ return -1;
 		case 3: /*  self_pri &&  peer_pri */
@@ -3177,7 +3434,7 @@ static enum drbd_conns drbd_sync_handshake(struct drbd_peer_device *peer_device,
 	drbd_uuid_dump(device, "peer", device->p_uuid,
 		       device->p_uuid[UI_SIZE], device->p_uuid[UI_FLAGS]);
 
-	hg = drbd_uuid_compare(device, &rule_nr);
+	hg = drbd_uuid_compare(device, peer_role, &rule_nr);
 	spin_unlock_irq(&device->ldev->md.uuid_lock);
 
 	drbd_info(device, "uuid_compare()=%d by rule %d\n", hg, rule_nr);
@@ -3186,6 +3443,15 @@ static enum drbd_conns drbd_sync_handshake(struct drbd_peer_device *peer_device,
 		drbd_alert(device, "Unrelated data, aborting!\n");
 		return C_MASK;
 	}
+	if (hg < -0x10000) {
+		int proto, fflags;
+		hg = -hg;
+		proto = hg & 0xff;
+		fflags = (hg >> 8) & 0xff;
+		drbd_alert(device, "To resolve this both sides have to support at least protocol %d and feature flags 0x%x\n",
+					proto, fflags);
+		return C_MASK;
+	}
 	if (hg < -1000) {
 		drbd_alert(device, "To resolve this both sides have to support at least protocol %d\n", -hg - 1000);
 		return C_MASK;
@@ -3415,7 +3681,8 @@ static int receive_protocol(struct drbd_connection *connection, struct packet_in
 		 */
 
 		peer_integrity_tfm = crypto_alloc_ahash(integrity_alg, 0, CRYPTO_ALG_ASYNC);
-		if (!peer_integrity_tfm) {
+		if (IS_ERR(peer_integrity_tfm)) {
+			peer_integrity_tfm = NULL;
 			drbd_err(connection, "peer data-integrity-alg %s not supported\n",
 				 integrity_alg);
 			goto disconnect;
@@ -3766,6 +4033,7 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info
 	struct drbd_peer_device *peer_device;
 	struct drbd_device *device;
 	struct p_sizes *p = pi->data;
+	struct o_qlim *o = (connection->agreed_features & DRBD_FF_WSAME) ? p->qlim : NULL;
 	enum determine_dev_size dd = DS_UNCHANGED;
 	sector_t p_size, p_usize, p_csize, my_usize;
 	int ldsc = 0; /* local disk size changed */
@@ -3785,6 +4053,7 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info
 	device->p_size = p_size;
 
 	if (get_ldev(device)) {
+		sector_t new_size, cur_size;
 		rcu_read_lock();
 		my_usize = rcu_dereference(device->ldev->disk_conf)->disk_size;
 		rcu_read_unlock();
@@ -3801,11 +4070,13 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info
 
 		/* Never shrink a device with usable data during connect.
 		   But allow online shrinking if we are connected. */
-		if (drbd_new_dev_size(device, device->ldev, p_usize, 0) <
-		    drbd_get_capacity(device->this_bdev) &&
+		new_size = drbd_new_dev_size(device, device->ldev, p_usize, 0);
+		cur_size = drbd_get_capacity(device->this_bdev);
+		if (new_size < cur_size &&
 		    device->state.disk >= D_OUTDATED &&
 		    device->state.conn < C_CONNECTED) {
-			drbd_err(device, "The peer's disk size is too small!\n");
+			drbd_err(device, "The peer's disk size is too small! (%llu < %llu sectors)\n",
+					(unsigned long long)new_size, (unsigned long long)cur_size);
 			conn_request_state(peer_device->connection, NS(conn, C_DISCONNECTING), CS_HARD);
 			put_ldev(device);
 			return -EIO;
@@ -3839,14 +4110,14 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info
 	}
 
 	device->peer_max_bio_size = be32_to_cpu(p->max_bio_size);
-	/* Leave drbd_reconsider_max_bio_size() before drbd_determine_dev_size().
+	/* Leave drbd_reconsider_queue_parameters() before drbd_determine_dev_size().
 	   In case we cleared the QUEUE_FLAG_DISCARD from our queue in
-	   drbd_reconsider_max_bio_size(), we can be sure that after
+	   drbd_reconsider_queue_parameters(), we can be sure that after
 	   drbd_determine_dev_size() no REQ_DISCARDs are in the queue. */
 
 	ddsf = be16_to_cpu(p->dds_flags);
 	if (get_ldev(device)) {
-		drbd_reconsider_max_bio_size(device, device->ldev);
+		drbd_reconsider_queue_parameters(device, device->ldev, o);
 		dd = drbd_determine_dev_size(device, ddsf, NULL);
 		put_ldev(device);
 		if (dd == DS_ERROR)
@@ -3866,7 +4137,7 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info
 		 * However, if he sends a zero current size,
 		 * take his (user-capped or) backing disk size anyways.
 		 */
-		drbd_reconsider_max_bio_size(device, NULL);
+		drbd_reconsider_queue_parameters(device, NULL, o);
 		drbd_set_my_capacity(device, p_csize ?: p_usize ?: p_size);
 	}
 
@@ -4599,9 +4870,75 @@ static int receive_out_of_sync(struct drbd_connection *connection, struct packet
 	return 0;
 }
 
+static int receive_rs_deallocated(struct drbd_connection *connection, struct packet_info *pi)
+{
+	struct drbd_peer_device *peer_device;
+	struct p_block_desc *p = pi->data;
+	struct drbd_device *device;
+	sector_t sector;
+	int size, err = 0;
+
+	peer_device = conn_peer_device(connection, pi->vnr);
+	if (!peer_device)
+		return -EIO;
+	device = peer_device->device;
+
+	sector = be64_to_cpu(p->sector);
+	size = be32_to_cpu(p->blksize);
+
+	dec_rs_pending(device);
+
+	if (get_ldev(device)) {
+		struct drbd_peer_request *peer_req;
+		const int op = REQ_OP_DISCARD;
+
+		peer_req = drbd_alloc_peer_req(peer_device, ID_SYNCER, sector,
+					       size, 0, GFP_NOIO);
+		if (!peer_req) {
+			put_ldev(device);
+			return -ENOMEM;
+		}
+
+		peer_req->w.cb = e_end_resync_block;
+		peer_req->submit_jif = jiffies;
+		peer_req->flags |= EE_IS_TRIM;
+
+		spin_lock_irq(&device->resource->req_lock);
+		list_add_tail(&peer_req->w.list, &device->sync_ee);
+		spin_unlock_irq(&device->resource->req_lock);
+
+		atomic_add(pi->size >> 9, &device->rs_sect_ev);
+		err = drbd_submit_peer_request(device, peer_req, op, 0, DRBD_FAULT_RS_WR);
+
+		if (err) {
+			spin_lock_irq(&device->resource->req_lock);
+			list_del(&peer_req->w.list);
+			spin_unlock_irq(&device->resource->req_lock);
+
+			drbd_free_peer_req(device, peer_req);
+			put_ldev(device);
+			err = 0;
+			goto fail;
+		}
+
+		inc_unacked(device);
+
+		/* No put_ldev() here. Gets called in drbd_endio_write_sec_final(),
+		   as well as drbd_rs_complete_io() */
+	} else {
+	fail:
+		drbd_rs_complete_io(device, sector);
+		drbd_send_ack_ex(peer_device, P_NEG_ACK, sector, size, ID_SYNCER);
+	}
+
+	atomic_add(size >> 9, &device->rs_sect_in);
+
+	return err;
+}
+
 struct data_cmd {
 	int expect_payload;
-	size_t pkt_size;
+	unsigned int pkt_size;
 	int (*fn)(struct drbd_connection *, struct packet_info *);
 };
 
@@ -4626,11 +4963,14 @@ static struct data_cmd drbd_cmd_handler[] = {
 	[P_OV_REQUEST]      = { 0, sizeof(struct p_block_req), receive_DataRequest },
 	[P_OV_REPLY]        = { 1, sizeof(struct p_block_req), receive_DataRequest },
 	[P_CSUM_RS_REQUEST] = { 1, sizeof(struct p_block_req), receive_DataRequest },
+	[P_RS_THIN_REQ]     = { 0, sizeof(struct p_block_req), receive_DataRequest },
 	[P_DELAY_PROBE]     = { 0, sizeof(struct p_delay_probe93), receive_skip },
 	[P_OUT_OF_SYNC]     = { 0, sizeof(struct p_block_desc), receive_out_of_sync },
 	[P_CONN_ST_CHG_REQ] = { 0, sizeof(struct p_req_state), receive_req_conn_state },
 	[P_PROTOCOL_UPDATE] = { 1, sizeof(struct p_protocol), receive_protocol },
 	[P_TRIM]	    = { 0, sizeof(struct p_trim), receive_Data },
+	[P_RS_DEALLOCATED]  = { 0, sizeof(struct p_block_desc), receive_rs_deallocated },
+	[P_WSAME]	    = { 1, sizeof(struct p_wsame), receive_Data },
 };
 
 static void drbdd(struct drbd_connection *connection)
@@ -4640,7 +4980,7 @@ static void drbdd(struct drbd_connection *connection)
 	int err;
 
 	while (get_t_state(&connection->receiver) == RUNNING) {
-		struct data_cmd *cmd;
+		struct data_cmd const *cmd;
 
 		drbd_thread_current_set_cpu(&connection->receiver);
 		update_receiver_timing_details(connection, drbd_recv_header);
@@ -4655,11 +4995,18 @@ static void drbdd(struct drbd_connection *connection)
 		}
 
 		shs = cmd->pkt_size;
+		if (pi.cmd == P_SIZES && connection->agreed_features & DRBD_FF_WSAME)
+			shs += sizeof(struct o_qlim);
 		if (pi.size > shs && !cmd->expect_payload) {
 			drbd_err(connection, "No payload expected %s l:%d\n",
 				 cmdname(pi.cmd), pi.size);
 			goto err_out;
 		}
+		if (pi.size < shs) {
+			drbd_err(connection, "%s: unexpected packet size, expected:%d received:%d\n",
+				 cmdname(pi.cmd), (int)shs, pi.size);
+			goto err_out;
+		}
 
 		if (shs) {
 			update_receiver_timing_details(connection, drbd_recv_all_warn);
@@ -4795,9 +5142,11 @@ static int drbd_disconnected(struct drbd_peer_device *peer_device)
 
 	drbd_md_sync(device);
 
-	/* serialize with bitmap writeout triggered by the state change,
-	 * if any. */
-	wait_event(device->misc_wait, !test_bit(BITMAP_IO, &device->flags));
+	if (get_ldev(device)) {
+		drbd_bitmap_io(device, &drbd_bm_write_copy_pages,
+				"write from disconnected", BM_LOCKED_CHANGE_ALLOWED);
+		put_ldev(device);
+	}
 
 	/* tcp_close and release of sendpage pages can be deferred.  I don't
 	 * want to use SO_LINGER, because apparently it can be deferred for
@@ -4904,8 +5253,12 @@ static int drbd_do_features(struct drbd_connection *connection)
 	drbd_info(connection, "Handshake successful: "
 	     "Agreed network protocol version %d\n", connection->agreed_pro_version);
 
-	drbd_info(connection, "Agreed to%ssupport TRIM on protocol level\n",
-		  connection->agreed_features & FF_TRIM ? " " : " not ");
+	drbd_info(connection, "Feature flags enabled on protocol level: 0x%x%s%s%s.\n",
+		  connection->agreed_features,
+		  connection->agreed_features & DRBD_FF_TRIM ? " TRIM" : "",
+		  connection->agreed_features & DRBD_FF_THIN_RESYNC ? " THIN_RESYNC" : "",
+		  connection->agreed_features & DRBD_FF_WSAME ? " WRITE_SAME" :
+		  connection->agreed_features ? "" : " none");
 
 	return 1;