drbd: Sending of big packets, for payloads from 64KByte to 4GByte

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

5 files changed, 139 insertions, 112 deletions

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 0fedcc0b8dc..3f10efc2ac1 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -337,13 +337,25 @@ static inline void bm_xfer_ctx_bit_to_word_offset(struct bm_xfer_ctx *c)
  * NOTE that the payload starts at a long aligned offset,
  * regardless of 32 or 64 bit arch!
  */
-struct p_header {
+struct p_header80 {
 	u32	  magic;
 	u16	  command;
 	u16	  length;	/* bytes of data after this header */
 	u8	  payload[0];
 } __packed;
-/* 8 bytes. packet FIXED for the next century! */
+
+/* Header for big packets, Used for data packets exceeding 64kB */
+struct p_header95 {
+	u16	  magic;	/* use DRBD_MAGIC_BIG here */
+	u16	  command;
+	u32	  length;
+	u8	  payload[0];
+} __packed;
+
+union p_header {
+	struct p_header80 h80;
+	struct p_header95 h95;
+};
 
 /*
  * short commands, packets without payload, plain p_header:
@@ -367,7 +379,7 @@ struct p_header {
 #define DP_MAY_SET_IN_SYNC    4
 
 struct p_data {
-	struct p_header head;
+	union p_header head;
 	u64	    sector;    /* 64 bits sector number */
 	u64	    block_id;  /* to identify the request in protocol B&C */
 	u32	    seq_num;
@@ -383,7 +395,7 @@ struct p_data {
  *   P_DATA_REQUEST, P_RS_DATA_REQUEST
  */
 struct p_block_ack {
-	struct p_header head;
+	struct p_header80 head;
 	u64	    sector;
 	u64	    block_id;
 	u32	    blksize;
@@ -392,7 +404,7 @@ struct p_block_ack {
 
 
 struct p_block_req {
-	struct p_header head;
+	struct p_header80 head;
 	u64 sector;
 	u64 block_id;
 	u32 blksize;
@@ -409,7 +421,7 @@ struct p_block_req {
  */
 
 struct p_handshake {
-	struct p_header head;	/* 8 bytes */
+	struct p_header80 head;	/* 8 bytes */
 	u32 protocol_min;
 	u32 feature_flags;
 	u32 protocol_max;
@@ -424,19 +436,19 @@ struct p_handshake {
 /* 80 bytes, FIXED for the next century */
 
 struct p_barrier {
-	struct p_header head;
+	struct p_header80 head;
 	u32 barrier;	/* barrier number _handle_ only */
 	u32 pad;	/* to multiple of 8 Byte */
 } __packed;
 
 struct p_barrier_ack {
-	struct p_header head;
+	struct p_header80 head;
 	u32 barrier;
 	u32 set_size;
 } __packed;
 
 struct p_rs_param {
-	struct p_header head;
+	struct p_header80 head;
 	u32 rate;
 
 	      /* Since protocol version 88 and higher. */
@@ -444,7 +456,7 @@ struct p_rs_param {
 } __packed;
 
 struct p_rs_param_89 {
-	struct p_header head;
+	struct p_header80 head;
 	u32 rate;
         /* protocol version 89: */
 	char verify_alg[SHARED_SECRET_MAX];
@@ -452,7 +464,7 @@ struct p_rs_param_89 {
 } __packed;
 
 struct p_rs_param_95 {
-	struct p_header head;
+	struct p_header80 head;
 	u32 rate;
 	char verify_alg[SHARED_SECRET_MAX];
 	char csums_alg[SHARED_SECRET_MAX];
@@ -468,7 +480,7 @@ enum drbd_conn_flags {
 };
 
 struct p_protocol {
-	struct p_header head;
+	struct p_header80 head;
 	u32 protocol;
 	u32 after_sb_0p;
 	u32 after_sb_1p;
@@ -482,17 +494,17 @@ struct p_protocol {
 } __packed;
 
 struct p_uuids {
-	struct p_header head;
+	struct p_header80 head;
 	u64 uuid[UI_EXTENDED_SIZE];
 } __packed;
 
 struct p_rs_uuid {
-	struct p_header head;
+	struct p_header80 head;
 	u64	    uuid;
 } __packed;
 
 struct p_sizes {
-	struct p_header head;
+	struct p_header80 head;
 	u64	    d_size;  /* size of disk */
 	u64	    u_size;  /* user requested size */
 	u64	    c_size;  /* current exported size */
@@ -502,18 +514,18 @@ struct p_sizes {
 } __packed;
 
 struct p_state {
-	struct p_header head;
+	struct p_header80 head;
 	u32	    state;
 } __packed;
 
 struct p_req_state {
-	struct p_header head;
+	struct p_header80 head;
 	u32	    mask;
 	u32	    val;
 } __packed;
 
 struct p_req_state_reply {
-	struct p_header head;
+	struct p_header80 head;
 	u32	    retcode;
 } __packed;
 
@@ -528,7 +540,7 @@ struct p_drbd06_param {
 } __packed;
 
 struct p_discard {
-	struct p_header head;
+	struct p_header80 head;
 	u64	    block_id;
 	u32	    seq_num;
 	u32	    pad;
@@ -544,7 +556,7 @@ enum drbd_bitmap_code {
 };
 
 struct p_compressed_bm {
-	struct p_header head;
+	struct p_header80 head;
 	/* (encoding & 0x0f): actual encoding, see enum drbd_bitmap_code
 	 * (encoding & 0x80): polarity (set/unset) of first runlength
 	 * ((encoding >> 4) & 0x07): pad_bits, number of trailing zero bits
@@ -555,10 +567,10 @@ struct p_compressed_bm {
 	u8 code[0];
 } __packed;
 
-struct p_delay_probe {
-	struct p_header head;
-	u32	seq_num; /* sequence number to match the two probe packets */
-	u32	offset;	 /* usecs the probe got sent after the reference time point */
+struct p_delay_probe93 {
+	struct p_header80 head;
+	u32     seq_num; /* sequence number to match the two probe packets */
+	u32     offset;  /* usecs the probe got sent after the reference time point */
 } __packed;
 
 /* DCBP: Drbd Compressed Bitmap Packet ... */
@@ -605,7 +617,7 @@ DCBP_set_pad_bits(struct p_compressed_bm *p, int n)
  * so we need to use the fixed size 4KiB page size
  * most architechtures have used for a long time.
  */
-#define BM_PACKET_PAYLOAD_BYTES (4096 - sizeof(struct p_header))
+#define BM_PACKET_PAYLOAD_BYTES (4096 - sizeof(struct p_header80))
 #define BM_PACKET_WORDS (BM_PACKET_PAYLOAD_BYTES/sizeof(long))
 #define BM_PACKET_VLI_BYTES_MAX (4096 - sizeof(struct p_compressed_bm))
 #if (PAGE_SIZE < 4096)
@@ -614,7 +626,7 @@ DCBP_set_pad_bits(struct p_compressed_bm *p, int n)
 #endif
 
 union p_polymorph {
-        struct p_header          header;
+        struct p_header80        header;
         struct p_handshake       handshake;
         struct p_data            data;
         struct p_block_ack       block_ack;
@@ -1188,12 +1200,12 @@ extern int drbd_send_sizes(struct drbd_conf *mdev, int trigger_reply, enum dds_f
 extern int _drbd_send_state(struct drbd_conf *mdev);
 extern int drbd_send_state(struct drbd_conf *mdev);
 extern int _drbd_send_cmd(struct drbd_conf *mdev, struct socket *sock,
-			enum drbd_packets cmd, struct p_header *h,
+			enum drbd_packets cmd, struct p_header80 *h,
 			size_t size, unsigned msg_flags);
 #define USE_DATA_SOCKET 1
 #define USE_META_SOCKET 0
 extern int drbd_send_cmd(struct drbd_conf *mdev, int use_data_socket,
-			enum drbd_packets cmd, struct p_header *h,
+			enum drbd_packets cmd, struct p_header80 *h,
 			size_t size);
 extern int drbd_send_cmd2(struct drbd_conf *mdev, enum drbd_packets cmd,
 			char *data, size_t size);
@@ -1936,19 +1948,19 @@ static inline void request_ping(struct drbd_conf *mdev)
 static inline int drbd_send_short_cmd(struct drbd_conf *mdev,
 	enum drbd_packets cmd)
 {
-	struct p_header h;
+	struct p_header80 h;
 	return drbd_send_cmd(mdev, USE_DATA_SOCKET, cmd, &h, sizeof(h));
 }
 
 static inline int drbd_send_ping(struct drbd_conf *mdev)
 {
-	struct p_header h;
+	struct p_header80 h;
 	return drbd_send_cmd(mdev, USE_META_SOCKET, P_PING, &h, sizeof(h));
 }
 
 static inline int drbd_send_ping_ack(struct drbd_conf *mdev)
 {
-	struct p_header h;
+	struct p_header80 h;
 	return drbd_send_cmd(mdev, USE_META_SOCKET, P_PING_ACK, &h, sizeof(h));
 }
 
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index db93eee7e54..f3f4ea9c5eb 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1647,7 +1647,7 @@ void drbd_thread_current_set_cpu(struct drbd_conf *mdev)
 
 /* the appropriate socket mutex must be held already */
 int _drbd_send_cmd(struct drbd_conf *mdev, struct socket *sock,
-			  enum drbd_packets cmd, struct p_header *h,
+			  enum drbd_packets cmd, struct p_header80 *h,
 			  size_t size, unsigned msg_flags)
 {
 	int sent, ok;
@@ -1657,7 +1657,7 @@ int _drbd_send_cmd(struct drbd_conf *mdev, struct socket *sock,
 
 	h->magic   = BE_DRBD_MAGIC;
 	h->command = cpu_to_be16(cmd);
-	h->length  = cpu_to_be16(size-sizeof(struct p_header));
+	h->length  = cpu_to_be16(size-sizeof(struct p_header80));
 
 	sent = drbd_send(mdev, sock, h, size, msg_flags);
 
@@ -1672,7 +1672,7 @@ int _drbd_send_cmd(struct drbd_conf *mdev, struct socket *sock,
  * when we hold the appropriate socket mutex.
  */
 int drbd_send_cmd(struct drbd_conf *mdev, int use_data_socket,
-		  enum drbd_packets cmd, struct p_header *h, size_t size)
+		  enum drbd_packets cmd, struct p_header80 *h, size_t size)
 {
 	int ok = 0;
 	struct socket *sock;
@@ -1700,7 +1700,7 @@ int drbd_send_cmd(struct drbd_conf *mdev, int use_data_socket,
 int drbd_send_cmd2(struct drbd_conf *mdev, enum drbd_packets cmd, char *data,
 		   size_t size)
 {
-	struct p_header h;
+	struct p_header80 h;
 	int ok;
 
 	h.magic   = BE_DRBD_MAGIC;
@@ -1807,7 +1807,7 @@ int drbd_send_protocol(struct drbd_conf *mdev)
 		strcpy(p->integrity_alg, mdev->net_conf->integrity_alg);
 
 	rv = drbd_send_cmd(mdev, USE_DATA_SOCKET, P_PROTOCOL,
-			   (struct p_header *)p, size);
+			   (struct p_header80 *)p, size);
 	kfree(p);
 	return rv;
 }
@@ -1833,7 +1833,7 @@ int _drbd_send_uuids(struct drbd_conf *mdev, u64 uuid_flags)
 	put_ldev(mdev);
 
 	return drbd_send_cmd(mdev, USE_DATA_SOCKET, P_UUIDS,
-			     (struct p_header *)&p, sizeof(p));
+			     (struct p_header80 *)&p, sizeof(p));
 }
 
 int drbd_send_uuids(struct drbd_conf *mdev)
@@ -1854,7 +1854,7 @@ int drbd_send_sync_uuid(struct drbd_conf *mdev, u64 val)
 	p.uuid = cpu_to_be64(val);
 
 	return drbd_send_cmd(mdev, USE_DATA_SOCKET, P_SYNC_UUID,
-			     (struct p_header *)&p, sizeof(p));
+			     (struct p_header80 *)&p, sizeof(p));
 }
 
 int drbd_send_sizes(struct drbd_conf *mdev, int trigger_reply, enum dds_flags flags)
@@ -1884,7 +1884,7 @@ int drbd_send_sizes(struct drbd_conf *mdev, int trigger_reply, enum dds_flags fl
 	p.dds_flags = cpu_to_be16(flags);
 
 	ok = drbd_send_cmd(mdev, USE_DATA_SOCKET, P_SIZES,
-			   (struct p_header *)&p, sizeof(p));
+			   (struct p_header80 *)&p, sizeof(p));
 	return ok;
 }
 
@@ -1909,7 +1909,7 @@ int drbd_send_state(struct drbd_conf *mdev)
 
 	if (likely(sock != NULL)) {
 		ok = _drbd_send_cmd(mdev, sock, P_STATE,
-				    (struct p_header *)&p, sizeof(p), 0);
+				    (struct p_header80 *)&p, sizeof(p), 0);
 	}
 
 	mutex_unlock(&mdev->data.mutex);
@@ -1927,7 +1927,7 @@ int drbd_send_state_req(struct drbd_conf *mdev,
 	p.val     = cpu_to_be32(val.i);
 
 	return drbd_send_cmd(mdev, USE_DATA_SOCKET, P_STATE_CHG_REQ,
-			     (struct p_header *)&p, sizeof(p));
+			     (struct p_header80 *)&p, sizeof(p));
 }
 
 int drbd_send_sr_reply(struct drbd_conf *mdev, int retcode)
@@ -1937,7 +1937,7 @@ int drbd_send_sr_reply(struct drbd_conf *mdev, int retcode)
 	p.retcode    = cpu_to_be32(retcode);
 
 	return drbd_send_cmd(mdev, USE_META_SOCKET, P_STATE_CHG_REPLY,
-			     (struct p_header *)&p, sizeof(p));
+			     (struct p_header80 *)&p, sizeof(p));
 }
 
 int fill_bitmap_rle_bits(struct drbd_conf *mdev,
@@ -2036,7 +2036,7 @@ int fill_bitmap_rle_bits(struct drbd_conf *mdev,
 
 enum { OK, FAILED, DONE }
 send_bitmap_rle_or_plain(struct drbd_conf *mdev,
-	struct p_header *h, struct bm_xfer_ctx *c)
+	struct p_header80 *h, struct bm_xfer_ctx *c)
 {
 	struct p_compressed_bm *p = (void*)h;
 	unsigned long num_words;
@@ -2066,12 +2066,12 @@ send_bitmap_rle_or_plain(struct drbd_conf *mdev,
 		if (len)
 			drbd_bm_get_lel(mdev, c->word_offset, num_words, (unsigned long*)h->payload);
 		ok = _drbd_send_cmd(mdev, mdev->data.socket, P_BITMAP,
-				   h, sizeof(struct p_header) + len, 0);
+				   h, sizeof(struct p_header80) + len, 0);
 		c->word_offset += num_words;
 		c->bit_offset = c->word_offset * BITS_PER_LONG;
 
 		c->packets[1]++;
-		c->bytes[1] += sizeof(struct p_header) + len;
+		c->bytes[1] += sizeof(struct p_header80) + len;
 
 		if (c->bit_offset > c->bm_bits)
 			c->bit_offset = c->bm_bits;
@@ -2087,14 +2087,14 @@ send_bitmap_rle_or_plain(struct drbd_conf *mdev,
 int _drbd_send_bitmap(struct drbd_conf *mdev)
 {
 	struct bm_xfer_ctx c;
-	struct p_header *p;
+	struct p_header80 *p;
 	int ret;
 
 	ERR_IF(!mdev->bitmap) return FALSE;
 
 	/* maybe we should use some per thread scratch page,
 	 * and allocate that during initial device creation? */
-	p = (struct p_header *) __get_free_page(GFP_NOIO);
+	p = (struct p_header80 *) __get_free_page(GFP_NOIO);
 	if (!p) {
 		dev_err(DEV, "failed to allocate one page buffer in %s\n", __func__);
 		return FALSE;
@@ -2152,7 +2152,7 @@ int drbd_send_b_ack(struct drbd_conf *mdev, u32 barrier_nr, u32 set_size)
 	if (mdev->state.conn < C_CONNECTED)
 		return FALSE;
 	ok = drbd_send_cmd(mdev, USE_META_SOCKET, P_BARRIER_ACK,
-			(struct p_header *)&p, sizeof(p));
+			(struct p_header80 *)&p, sizeof(p));
 	return ok;
 }
 
@@ -2180,7 +2180,7 @@ static int _drbd_send_ack(struct drbd_conf *mdev, enum drbd_packets cmd,
 	if (!mdev->meta.socket || mdev->state.conn < C_CONNECTED)
 		return FALSE;
 	ok = drbd_send_cmd(mdev, USE_META_SOCKET, cmd,
-				(struct p_header *)&p, sizeof(p));
+				(struct p_header80 *)&p, sizeof(p));
 	return ok;
 }
 
@@ -2188,8 +2188,8 @@ int drbd_send_ack_dp(struct drbd_conf *mdev, enum drbd_packets cmd,
 		     struct p_data *dp)
 {
 	const int header_size = sizeof(struct p_data)
-			      - sizeof(struct p_header);
-	int data_size  = ((struct p_header *)dp)->length - header_size;
+			      - sizeof(struct p_header80);
+	int data_size  = ((struct p_header80 *)dp)->length - header_size;
 
 	return _drbd_send_ack(mdev, cmd, dp->sector, cpu_to_be32(data_size),
 			      dp->block_id);
@@ -2238,7 +2238,7 @@ int drbd_send_drequest(struct drbd_conf *mdev, int cmd,
 	p.blksize  = cpu_to_be32(size);
 
 	ok = drbd_send_cmd(mdev, USE_DATA_SOCKET, cmd,
-				(struct p_header *)&p, sizeof(p));
+				(struct p_header80 *)&p, sizeof(p));
 	return ok;
 }
 
@@ -2256,7 +2256,7 @@ int drbd_send_drequest_csum(struct drbd_conf *mdev,
 
 	p.head.magic   = BE_DRBD_MAGIC;
 	p.head.command = cpu_to_be16(cmd);
-	p.head.length  = cpu_to_be16(sizeof(p) - sizeof(struct p_header) + digest_size);
+	p.head.length  = cpu_to_be16(sizeof(p) - sizeof(struct p_header80) + digest_size);
 
 	mutex_lock(&mdev->data.mutex);
 
@@ -2278,7 +2278,7 @@ int drbd_send_ov_request(struct drbd_conf *mdev, sector_t sector, int size)
 	p.blksize  = cpu_to_be32(size);
 
 	ok = drbd_send_cmd(mdev, USE_DATA_SOCKET, P_OV_REQUEST,
-			   (struct p_header *)&p, sizeof(p));
+			   (struct p_header80 *)&p, sizeof(p));
 	return ok;
 }
 
@@ -2447,10 +2447,17 @@ int drbd_send_dblock(struct drbd_conf *mdev, struct drbd_request *req)
 	dgs = (mdev->agreed_pro_version >= 87 && mdev->integrity_w_tfm) ?
 		crypto_hash_digestsize(mdev->integrity_w_tfm) : 0;
 
-	p.head.magic   = BE_DRBD_MAGIC;
-	p.head.command = cpu_to_be16(P_DATA);
-	p.head.length  =
-		cpu_to_be16(sizeof(p) - sizeof(struct p_header) + dgs + req->size);
+	if (req->size <= (1 << 15)) {
+		p.head.h80.magic   = BE_DRBD_MAGIC;
+		p.head.h80.command = cpu_to_be16(P_DATA);
+		p.head.h80.length  =
+			cpu_to_be16(sizeof(p) - sizeof(union p_header) + dgs + req->size);
+	} else {
+		p.head.h95.magic   = BE_DRBD_MAGIC_BIG;
+		p.head.h95.command = cpu_to_be16(P_DATA);
+		p.head.h95.length  =
+			cpu_to_be32(sizeof(p) - sizeof(union p_header) + dgs + req->size);
+	}
 
 	p.sector   = cpu_to_be64(req->sector);
 	p.block_id = (unsigned long)req;
@@ -2511,10 +2518,17 @@ int drbd_send_block(struct drbd_conf *mdev, enum drbd_packets cmd,
 	dgs = (mdev->agreed_pro_version >= 87 && mdev->integrity_w_tfm) ?
 		crypto_hash_digestsize(mdev->integrity_w_tfm) : 0;
 
-	p.head.magic   = BE_DRBD_MAGIC;
-	p.head.command = cpu_to_be16(cmd);
-	p.head.length  =
-		cpu_to_be16(sizeof(p) - sizeof(struct p_header) + dgs + e->size);
+	if (e->size <= (1 << 15)) {
+		p.head.h80.magic   = BE_DRBD_MAGIC;
+		p.head.h80.command = cpu_to_be16(cmd);
+		p.head.h80.length  =
+			cpu_to_be16(sizeof(p) - sizeof(struct p_header80) + dgs + e->size);
+	} else {
+		p.head.h95.magic   = BE_DRBD_MAGIC_BIG;
+		p.head.h95.command = cpu_to_be16(cmd);
+		p.head.h95.length  =
+			cpu_to_be32(sizeof(p) - sizeof(struct p_header80) + dgs + e->size);
+	}
 
 	p.sector   = cpu_to_be64(e->sector);
 	p.block_id = e->block_id;
@@ -2527,8 +2541,7 @@ int drbd_send_block(struct drbd_conf *mdev, enum drbd_packets cmd,
 	if (!drbd_get_data_sock(mdev))
 		return 0;
 
-	ok = sizeof(p) == drbd_send(mdev, mdev->data.socket, &p,
-					sizeof(p), dgs ? MSG_MORE : 0);
+	ok = sizeof(p) == drbd_send(mdev, mdev->data.socket, &p, sizeof(p), dgs ? MSG_MORE : 0);
 	if (ok && dgs) {
 		dgb = mdev->int_dig_out;
 		drbd_csum_ee(mdev, mdev->integrity_w_tfm, e, dgb);
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 591a171291d..9b3321e2c3c 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -720,14 +720,14 @@ out:
 static int drbd_send_fp(struct drbd_conf *mdev,
 	struct socket *sock, enum drbd_packets cmd)
 {
-	struct p_header *h = (struct p_header *) &mdev->data.sbuf.header;
+	struct p_header80 *h = (struct p_header80 *) &mdev->data.sbuf.header;
 
 	return _drbd_send_cmd(mdev, sock, cmd, h, sizeof(*h), 0);
 }
 
 static enum drbd_packets drbd_recv_fp(struct drbd_conf *mdev, struct socket *sock)
 {
-	struct p_header *h = (struct p_header *) &mdev->data.sbuf.header;
+	struct p_header80 *h = (struct p_header80 *) &mdev->data.sbuf.header;
 	int rr;
 
 	rr = drbd_recv_short(mdev, sock, h, sizeof(*h), 0);
@@ -944,7 +944,7 @@ out_release_sockets:
 	return -1;
 }
 
-static int drbd_recv_header(struct drbd_conf *mdev, struct p_header *h)
+static int drbd_recv_header(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	int r;
 
@@ -1266,7 +1266,7 @@ int w_e_reissue(struct drbd_conf *mdev, struct drbd_work *w, int cancel) __relea
 	return 1;
 }
 
-static int receive_Barrier(struct drbd_conf *mdev, struct p_header *h)
+static int receive_Barrier(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	int rv, issue_flush;
 	struct p_barrier *p = (struct p_barrier *)h;
@@ -1570,7 +1570,7 @@ fail:
 	return FALSE;
 }
 
-static int receive_DataReply(struct drbd_conf *mdev, struct p_header *h)
+static int receive_DataReply(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	struct drbd_request *req;
 	sector_t sector;
@@ -1610,7 +1610,7 @@ static int receive_DataReply(struct drbd_conf *mdev, struct p_header *h)
 	return ok;
 }
 
-static int receive_RSDataReply(struct drbd_conf *mdev, struct p_header *h)
+static int receive_RSDataReply(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	sector_t sector;
 	unsigned int header_size, data_size;
@@ -1767,7 +1767,7 @@ static int drbd_wait_peer_seq(struct drbd_conf *mdev, const u32 packet_seq)
 }
 
 /* mirrored write */
-static int receive_Data(struct drbd_conf *mdev, struct p_header *h)
+static int receive_Data(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	sector_t sector;
 	struct drbd_epoch_entry *e;
@@ -2066,7 +2066,7 @@ int drbd_rs_should_slow_down(struct drbd_conf *mdev)
 }
 
 
-static int receive_DataRequest(struct drbd_conf *mdev, struct p_header *h)
+static int receive_DataRequest(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	sector_t sector;
 	const sector_t capacity = drbd_get_capacity(mdev->this_bdev);
@@ -2756,7 +2756,7 @@ static int cmp_after_sb(enum drbd_after_sb_p peer, enum drbd_after_sb_p self)
 	return 1;
 }
 
-static int receive_protocol(struct drbd_conf *mdev, struct p_header *h)
+static int receive_protocol(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	struct p_protocol *p = (struct p_protocol *)h;
 	int header_size, data_size;
@@ -2862,7 +2862,7 @@ struct crypto_hash *drbd_crypto_alloc_digest_safe(const struct drbd_conf *mdev,
 	return tfm;
 }
 
-static int receive_SyncParam(struct drbd_conf *mdev, struct p_header *h)
+static int receive_SyncParam(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	int ok = TRUE;
 	struct p_rs_param_95 *p = (struct p_rs_param_95 *)h;
@@ -3032,7 +3032,7 @@ static void warn_if_differ_considerably(struct drbd_conf *mdev,
 		     (unsigned long long)a, (unsigned long long)b);
 }
 
-static int receive_sizes(struct drbd_conf *mdev, struct p_header *h)
+static int receive_sizes(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	struct p_sizes *p = (struct p_sizes *)h;
 	enum determine_dev_size dd = unchanged;
@@ -3148,7 +3148,7 @@ static int receive_sizes(struct drbd_conf *mdev, struct p_header *h)
 	return TRUE;
 }
 
-static int receive_uuids(struct drbd_conf *mdev, struct p_header *h)
+static int receive_uuids(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	struct p_uuids *p = (struct p_uuids *)h;
 	u64 *p_uuid;
@@ -3241,7 +3241,7 @@ static union drbd_state convert_state(union drbd_state ps)
 	return ms;
 }
 
-static int receive_req_state(struct drbd_conf *mdev, struct p_header *h)
+static int receive_req_state(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	struct p_req_state *p = (struct p_req_state *)h;
 	union drbd_state mask, val;
@@ -3271,7 +3271,7 @@ static int receive_req_state(struct drbd_conf *mdev, struct p_header *h)
 	return TRUE;
 }
 
-static int receive_state(struct drbd_conf *mdev, struct p_header *h)
+static int receive_state(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	struct p_state *p = (struct p_state *)h;
 	enum drbd_conns nconn, oconn;
@@ -3395,7 +3395,7 @@ static int receive_state(struct drbd_conf *mdev, struct p_header *h)
 	return TRUE;
 }
 
-static int receive_sync_uuid(struct drbd_conf *mdev, struct p_header *h)
+static int receive_sync_uuid(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	struct p_rs_uuid *p = (struct p_rs_uuid *)h;
 
@@ -3428,7 +3428,7 @@ static int receive_sync_uuid(struct drbd_conf *mdev, struct p_header *h)
 enum receive_bitmap_ret { OK, DONE, FAILED };
 
 static enum receive_bitmap_ret
-receive_bitmap_plain(struct drbd_conf *mdev, struct p_header *h,
+receive_bitmap_plain(struct drbd_conf *mdev, struct p_header80 *h,
 	unsigned long *buffer, struct bm_xfer_ctx *c)
 {
 	unsigned num_words = min_t(size_t, BM_PACKET_WORDS, c->bm_words - c->word_offset);
@@ -3533,7 +3533,7 @@ void INFO_bm_xfer_stats(struct drbd_conf *mdev,
 		const char *direction, struct bm_xfer_ctx *c)
 {
 	/* what would it take to transfer it "plaintext" */
-	unsigned plain = sizeof(struct p_header) *
+	unsigned plain = sizeof(struct p_header80) *
 		((c->bm_words+BM_PACKET_WORDS-1)/BM_PACKET_WORDS+1)
 		+ c->bm_words * sizeof(long);
 	unsigned total = c->bytes[0] + c->bytes[1];
@@ -3571,7 +3571,7 @@ void INFO_bm_xfer_stats(struct drbd_conf *mdev,
    in order to be agnostic to the 32 vs 64 bits issue.
 
    returns 0 on failure, 1 if we successfully received it. */
-static int receive_bitmap(struct drbd_conf *mdev, struct p_header *h)
+static int receive_bitmap(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	struct bm_xfer_ctx c;
 	void *buffer;
@@ -3623,7 +3623,7 @@ static int receive_bitmap(struct drbd_conf *mdev, struct p_header *h)
 		}
 
 		c.packets[h->command == P_BITMAP]++;
-		c.bytes[h->command == P_BITMAP] += sizeof(struct p_header) + h->length;
+		c.bytes[h->command == P_BITMAP] += sizeof(struct p_header80) + h->length;
 
 		if (ret != OK)
 			break;
@@ -3659,7 +3659,7 @@ static int receive_bitmap(struct drbd_conf *mdev, struct p_header *h)
 	return ok;
 }
 
-static int receive_skip_(struct drbd_conf *mdev, struct p_header *h, int silent)
+static int receive_skip_(struct drbd_conf *mdev, struct p_header80 *h, int silent)
 {
 	/* TODO zero copy sink :) */
 	static char sink[128];
@@ -3679,17 +3679,17 @@ static int receive_skip_(struct drbd_conf *mdev, struct p_header *h, int silent)
 	return size == 0;
 }
 
-static int receive_skip(struct drbd_conf *mdev, struct p_header *h)
+static int receive_skip(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	return receive_skip_(mdev, h, 0);
 }
 
-static int receive_skip_silent(struct drbd_conf *mdev, struct p_header *h)
+static int receive_skip_silent(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	return receive_skip_(mdev, h, 1);
 }
 
-static int receive_UnplugRemote(struct drbd_conf *mdev, struct p_header *h)
+static int receive_UnplugRemote(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	if (mdev->state.disk >= D_INCONSISTENT)
 		drbd_kick_lo(mdev);
@@ -3701,7 +3701,7 @@ static int receive_UnplugRemote(struct drbd_conf *mdev, struct p_header *h)
 	return TRUE;
 }
 
-typedef int (*drbd_cmd_handler_f)(struct drbd_conf *, struct p_header *);
+typedef int (*drbd_cmd_handler_f)(struct drbd_conf *, struct p_header80 *);
 
 static drbd_cmd_handler_f drbd_default_handler[] = {
 	[P_DATA]	    = receive_Data,
@@ -3736,7 +3736,7 @@ static drbd_cmd_handler_f *drbd_opt_cmd_handler;
 static void drbdd(struct drbd_conf *mdev)
 {
 	drbd_cmd_handler_f handler;
-	struct p_header *header = &mdev->data.rbuf.header;
+	struct p_header80 *header = &mdev->data.rbuf.header;
 
 	while (get_t_state(&mdev->receiver) == Running) {
 		drbd_thread_current_set_cpu(mdev);
@@ -3964,7 +3964,7 @@ static int drbd_send_handshake(struct drbd_conf *mdev)
 	p->protocol_min = cpu_to_be32(PRO_VERSION_MIN);
 	p->protocol_max = cpu_to_be32(PRO_VERSION_MAX);
 	ok = _drbd_send_cmd( mdev, mdev->data.socket, P_HAND_SHAKE,
-			     (struct p_header *)p, sizeof(*p), 0 );
+			     (struct p_header80 *)p, sizeof(*p), 0 );
 	mutex_unlock(&mdev->data.mutex);
 	return ok;
 }
@@ -3981,7 +3981,7 @@ static int drbd_do_handshake(struct drbd_conf *mdev)
 	/* ASSERT current == mdev->receiver ... */
 	struct p_handshake *p = &mdev->data.rbuf.handshake;
 	const int expect = sizeof(struct p_handshake)
-			  -sizeof(struct p_header);
+			  -sizeof(struct p_header80);
 	int rv;
 
 	rv = drbd_send_handshake(mdev);
@@ -4058,7 +4058,7 @@ static int drbd_do_auth(struct drbd_conf *mdev)
 	char *response = NULL;
 	char *right_response = NULL;
 	char *peers_ch = NULL;
-	struct p_header p;
+	struct p_header80 p;
 	unsigned int key_len = strlen(mdev->net_conf->shared_secret);
 	unsigned int resp_size;
 	struct hash_desc desc;
@@ -4231,7 +4231,7 @@ int drbdd_init(struct drbd_thread *thi)
 
 /* ********* acknowledge sender ******** */
 
-static int got_RqSReply(struct drbd_conf *mdev, struct p_header *h)
+static int got_RqSReply(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	struct p_req_state_reply *p = (struct p_req_state_reply *)h;
 
@@ -4249,13 +4249,13 @@ static int got_RqSReply(struct drbd_conf *mdev, struct p_header *h)
 	return TRUE;
 }
 
-static int got_Ping(struct drbd_conf *mdev, struct p_header *h)
+static int got_Ping(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	return drbd_send_ping_ack(mdev);
 
 }
 
-static int got_PingAck(struct drbd_conf *mdev, struct p_header *h)
+static int got_PingAck(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	/* restore idle timeout */
 	mdev->meta.socket->sk->sk_rcvtimeo = mdev->net_conf->ping_int*HZ;
@@ -4265,7 +4265,7 @@ static int got_PingAck(struct drbd_conf *mdev, struct p_header *h)
 	return TRUE;
 }
 
-static int got_IsInSync(struct drbd_conf *mdev, struct p_header *h)
+static int got_IsInSync(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	struct p_block_ack *p = (struct p_block_ack *)h;
 	sector_t sector = be64_to_cpu(p->sector);
@@ -4336,7 +4336,7 @@ static int validate_req_change_req_state(struct drbd_conf *mdev,
 	return TRUE;
 }
 
-static int got_BlockAck(struct drbd_conf *mdev, struct p_header *h)
+static int got_BlockAck(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	struct p_block_ack *p = (struct p_block_ack *)h;
 	sector_t sector = be64_to_cpu(p->sector);
@@ -4376,7 +4376,7 @@ static int got_BlockAck(struct drbd_conf *mdev, struct p_header *h)
 		_ack_id_to_req, __func__ , what);
 }
 
-static int got_NegAck(struct drbd_conf *mdev, struct p_header *h)
+static int got_NegAck(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	struct p_block_ack *p = (struct p_block_ack *)h;
 	sector_t sector = be64_to_cpu(p->sector);
@@ -4396,7 +4396,7 @@ static int got_NegAck(struct drbd_conf *mdev, struct p_header *h)
 		_ack_id_to_req, __func__ , neg_acked);
 }
 
-static int got_NegDReply(struct drbd_conf *mdev, struct p_header *h)
+static int got_NegDReply(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	struct p_block_ack *p = (struct p_block_ack *)h;
 	sector_t sector = be64_to_cpu(p->sector);
@@ -4409,7 +4409,7 @@ static int got_NegDReply(struct drbd_conf *mdev, struct p_header *h)
 		_ar_id_to_req, __func__ , neg_acked);
 }
 
-static int got_NegRSDReply(struct drbd_conf *mdev, struct p_header *h)
+static int got_NegRSDReply(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	sector_t sector;
 	int size;
@@ -4431,7 +4431,7 @@ static int got_NegRSDReply(struct drbd_conf *mdev, struct p_header *h)
 	return TRUE;
 }
 
-static int got_BarrierAck(struct drbd_conf *mdev, struct p_header *h)
+static int got_BarrierAck(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	struct p_barrier_ack *p = (struct p_barrier_ack *)h;
 
@@ -4440,7 +4440,7 @@ static int got_BarrierAck(struct drbd_conf *mdev, struct p_header *h)
 	return TRUE;
 }
 
-static int got_OVResult(struct drbd_conf *mdev, struct p_header *h)
+static int got_OVResult(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	struct p_block_ack *p = (struct p_block_ack *)h;
 	struct drbd_work *w;
@@ -4474,7 +4474,7 @@ static int got_OVResult(struct drbd_conf *mdev, struct p_header *h)
 	return TRUE;
 }
 
-static int got_something_to_ignore_m(struct drbd_conf *mdev, struct p_header *h)
+static int got_something_to_ignore_m(struct drbd_conf *mdev, struct p_header80 *h)
 {
 	/* IGNORE */
 	return TRUE;
@@ -4482,7 +4482,7 @@ static int got_something_to_ignore_m(struct drbd_conf *mdev, struct p_header *h)
 
 struct asender_cmd {
 	size_t pkt_size;
-	int (*process)(struct drbd_conf *mdev, struct p_header *h);
+	int (*process)(struct drbd_conf *mdev, struct p_header80 *h);
 };
 
 static struct asender_cmd *get_asender_cmd(int cmd)
@@ -4491,8 +4491,8 @@ static struct asender_cmd *get_asender_cmd(int cmd)
 		/* anything missing from this table is in
 		 * the drbd_cmd_handler (drbd_default_handler) table,
 		 * see the beginning of drbdd() */
-	[P_PING]	    = { sizeof(struct p_header), got_Ping },
-	[P_PING_ACK]	    = { sizeof(struct p_header), got_PingAck },
+	[P_PING]	    = { sizeof(struct p_header80), got_Ping },
+	[P_PING_ACK]	    = { sizeof(struct p_header80), got_PingAck },
 	[P_RECV_ACK]	    = { sizeof(struct p_block_ack), got_BlockAck },
 	[P_WRITE_ACK]	    = { sizeof(struct p_block_ack), got_BlockAck },
 	[P_RS_WRITE_ACK]    = { sizeof(struct p_block_ack), got_BlockAck },
@@ -4504,7 +4504,7 @@ static struct asender_cmd *get_asender_cmd(int cmd)
 	[P_BARRIER_ACK]	    = { sizeof(struct p_barrier_ack), got_BarrierAck },
 	[P_STATE_CHG_REPLY] = { sizeof(struct p_req_state_reply), got_RqSReply },
 	[P_RS_IS_IN_SYNC]   = { sizeof(struct p_block_ack), got_IsInSync },
-	[P_DELAY_PROBE]     = { sizeof(struct p_delay_probe), got_something_to_ignore_m },
+	[P_DELAY_PROBE]     = { sizeof(struct p_delay_probe93), got_something_to_ignore_m },
 	[P_MAX_CMD]	    = { 0, NULL },
 	};
 	if (cmd > P_MAX_CMD || asender_tbl[cmd].process == NULL)
@@ -4515,13 +4515,13 @@ static struct asender_cmd *get_asender_cmd(int cmd)
 int drbd_asender(struct drbd_thread *thi)
 {
 	struct drbd_conf *mdev = thi->mdev;
-	struct p_header *h = &mdev->meta.rbuf.header;
+	struct p_header80 *h = &mdev->meta.rbuf.header;
 	struct asender_cmd *cmd = NULL;
 
 	int rv, len;
 	void *buf    = h;
 	int received = 0;
-	int expect   = sizeof(struct p_header);
+	int expect   = sizeof(struct p_header80);
 	int empty;
 
 	sprintf(current->comm, "drbd%d_asender", mdev_to_minor(mdev));
@@ -4621,7 +4621,7 @@ int drbd_asender(struct drbd_thread *thi)
 				goto disconnect;
 			}
 			expect = cmd->pkt_size;
-			ERR_IF(len != expect-sizeof(struct p_header))
+			ERR_IF(len != expect-sizeof(struct p_header80))
 				goto reconnect;
 		}
 		if (received == expect) {
@@ -4631,7 +4631,7 @@ int drbd_asender(struct drbd_thread *thi)
 
 			buf	 = h;
 			received = 0;
-			expect	 = sizeof(struct p_header);
+			expect	 = sizeof(struct p_header80);
 			cmd	 = NULL;
 		}
 	}
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 1eeb55423b3..3d0e14e3ade 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -1204,7 +1204,7 @@ int w_send_barrier(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
 	 * dec_ap_pending will be done in got_BarrierAck
 	 * or (on connection loss) in w_clear_epoch.  */
 	ok = _drbd_send_cmd(mdev, mdev->data.socket, P_BARRIER,
-				(struct p_header *)p, sizeof(*p), 0);
+				(struct p_header80 *)p, sizeof(*p), 0);
 	drbd_put_data_sock(mdev);
 
 	return ok;
diff --git a/include/linux/drbd.h b/include/linux/drbd.h
index 0b2bfb58d9c..89718a39791 100644
--- a/include/linux/drbd.h
+++ b/include/linux/drbd.h
@@ -318,6 +318,8 @@ enum drbd_timeout_flag {
 
 #define DRBD_MAGIC 0x83740267
 #define BE_DRBD_MAGIC __constant_cpu_to_be32(DRBD_MAGIC)
+#define DRBD_MAGIC_BIG 0x835a
+#define BE_DRBD_MAGIC_BIG __constant_cpu_to_be16(DRBD_MAGIC_BIG)
 
 /* these are of type "int" */
 #define DRBD_MD_INDEX_INTERNAL -1