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Message-Id: <1238431643-19433-7-git-send-email-philipp.reisner@linbit.com>
Date:	Mon, 30 Mar 2009 18:47:14 +0200
From:	Philipp Reisner <philipp.reisner@...bit.com>
To:	linux-kernel@...r.kernel.org
Cc:	gregkh@...e.de, jens.axboe@...cle.com, nab@...ingtidestorage.com,
	andi@...stfloor.org, Philipp Reisner <philipp.reisner@...bit.com>,
	Lars Ellenberg <lars.ellenberg@...bit.com>
Subject: [PATCH 06/13] DRBD: internal_data_structures

The big "struct drbd_conf". It actually describes one DRBD device.

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

---
diff -uNrp linux-2.6.29/drivers/block/drbd/drbd_int.h linux-2.6.29-drbd/drivers/block/drbd/drbd_int.h
--- linux-2.6.29/drivers/block/drbd/drbd_int.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.29-drbd/drivers/block/drbd/drbd_int.h	2009-03-30 18:46:14.164468432 +0200
@@ -0,0 +1,2320 @@
+/*
+  drbd_int.h
+
+  This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
+
+  Copyright (C) 2001-2008, LINBIT Information Technologies GmbH.
+  Copyright (C) 1999-2008, Philipp Reisner <philipp.reisner@...bit.com>.
+  Copyright (C) 2002-2008, Lars Ellenberg <lars.ellenberg@...bit.com>.
+
+  drbd is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2, or (at your option)
+  any later version.
+
+  drbd is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with drbd; see the file COPYING.  If not, write to
+  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#ifndef _DRBD_INT_H
+#define _DRBD_INT_H
+
+#include <linux/compiler.h>
+#include <linux/types.h>
+#include <linux/version.h>
+#include <linux/list.h>
+#include <linux/sched.h>
+#include <linux/bitops.h>
+#include <linux/slab.h>
+#include <linux/crypto.h>
+#include <linux/tcp.h>
+#include <linux/mutex.h>
+#include <linux/major.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+#include <net/tcp.h>
+#include "lru_cache.h"
+
+#ifdef __CHECKER__
+# define __protected_by(x)       __attribute__((require_context(x,1,999,"rdwr")))
+# define __protected_read_by(x)  __attribute__((require_context(x,1,999,"read")))
+# define __protected_write_by(x) __attribute__((require_context(x,1,999,"write")))
+# define __must_hold(x)       __attribute__((context(x,1,1), require_context(x,1,999,"call")))
+#else
+# define __protected_by(x)
+# define __protected_read_by(x)
+# define __protected_write_by(x)
+# define __must_hold(x)
+#endif
+
+#define __no_warn(lock, stmt) do { __acquire(lock); stmt; __release(lock); } while (0)
+
+/* module parameter, defined in drbd_main.c */
+extern unsigned int minor_count;
+extern int allow_oos;
+extern unsigned int cn_idx;
+
+#ifdef DRBD_ENABLE_FAULTS
+extern int enable_faults;
+extern int fault_rate;
+extern int fault_devs;
+#endif
+
+extern char usermode_helper[];
+
+
+#ifndef TRUE
+#define TRUE 1
+#endif
+#ifndef FALSE
+#define FALSE 0
+#endif
+
+/* I don't remember why XCPU ...
+ * This is used to wake the asender,
+ * and to interrupt sending the sending task
+ * on disconnect.
+ */
+#define DRBD_SIG SIGXCPU
+
+/* This is used to stop/restart our threads.
+ * Cannot use SIGTERM nor SIGKILL, since these
+ * are sent out by init on runlevel changes
+ * I choose SIGHUP for now.
+ */
+#define DRBD_SIGKILL SIGHUP
+
+/* All EEs on the free list should have ID_VACANT (== 0)
+ * freshly allocated EEs get !ID_VACANT (== 1)
+ * so if it says "cannot dereference null pointer at adress 0x00000001",
+ * it is most likely one of these :( */
+
+#define ID_IN_SYNC      (4711ULL)
+#define ID_OUT_OF_SYNC  (4712ULL)
+
+#define ID_SYNCER (-1ULL)
+#define ID_VACANT 0
+#define is_syncer_block_id(id) ((id) == ID_SYNCER)
+
+struct drbd_conf;
+
+#ifdef DBG_ALL_SYMBOLS
+# define STATIC
+#else
+# define STATIC static
+#endif
+
+/*
+ * Some Message Macros
+ *************************/
+
+#define DUMPP(A)   ERR(#A " = %p in %s:%d\n", (A), __FILE__, __LINE__);
+#define DUMPLU(A)  ERR(#A " = %lu in %s:%d\n", (unsigned long)(A), __FILE__, __LINE__);
+#define DUMPLLU(A) ERR(#A " = %llu in %s:%d\n", (unsigned long long)(A), __FILE__, __LINE__);
+#define DUMPLX(A)  ERR(#A " = %lx in %s:%d\n", (A), __FILE__, __LINE__);
+#define DUMPI(A)   ERR(#A " = %d in %s:%d\n", (int)(A), __FILE__, __LINE__);
+
+
+#define PRINTK(level, fmt, args...) \
+	printk(level "drbd%d: " fmt, \
+		mdev->minor , ##args)
+
+#define ALERT(fmt, args...) PRINTK(KERN_ALERT, fmt , ##args)
+#define ERR(fmt, args...)   PRINTK(KERN_ERR, fmt , ##args)
+/* nowadays, WARN() is defined as BUG() without crash in bug.h */
+#define drbd_WARN(fmt, args...)  PRINTK(KERN_WARNING, fmt , ##args)
+#define INFO(fmt, args...)  PRINTK(KERN_INFO, fmt , ##args)
+#define DBG(fmt, args...)   PRINTK(KERN_DEBUG, fmt , ##args)
+
+#define D_ASSERT(exp)	if (!(exp)) \
+	 ERR("ASSERT( " #exp " ) in %s:%d\n", __FILE__, __LINE__)
+
+#define ERR_IF(exp) if (({				\
+	int _b = (exp) != 0;				\
+	if (_b) ERR("%s: (%s) in %s:%d\n",		\
+		__func__, #exp, __FILE__, __LINE__);	\
+	 _b;						\
+	}))
+
+/* Defines to control fault insertion */
+enum {
+    DRBD_FAULT_MD_WR = 0,	/* meta data write */
+    DRBD_FAULT_MD_RD,		/*           read  */
+    DRBD_FAULT_RS_WR,		/* resync          */
+    DRBD_FAULT_RS_RD,
+    DRBD_FAULT_DT_WR,		/* data            */
+    DRBD_FAULT_DT_RD,
+    DRBD_FAULT_DT_RA,		/* data read ahead */
+    DRBD_FAULT_AL_EE,		/* alloc ee */
+
+    DRBD_FAULT_MAX,
+};
+
+#ifdef DRBD_ENABLE_FAULTS
+extern unsigned int
+_drbd_insert_fault(struct drbd_conf *mdev, unsigned int type);
+static inline int
+drbd_insert_fault(struct drbd_conf *mdev, unsigned int type) {
+    return fault_rate &&
+	    (enable_faults & (1<<type)) &&
+	    _drbd_insert_fault(mdev, type);
+}
+#define FAULT_ACTIVE(_m, _t) (drbd_insert_fault((_m), (_t)))
+
+#else
+#define FAULT_ACTIVE(_m, _t) (0)
+#endif
+
+/* integer division, round _UP_ to the next integer */
+#define div_ceil(A, B) ((A)/(B) + ((A)%(B) ? 1 : 0))
+/* usual integer division */
+#define div_floor(A, B) ((A)/(B))
+
+/* drbd_meta-data.c (still in drbd_main.c) */
+/* 4th incarnation of the disk layout. */
+#define DRBD_MD_MAGIC (DRBD_MAGIC+4)
+
+extern struct drbd_conf **minor_table;
+extern struct ratelimit_state drbd_ratelimit_state;
+
+/***
+ * on the wire
+ *********************************************************************/
+
+enum Drbd_Packet_Cmd {
+	/* receiver (data socket) */
+	Data              = 0x00,
+	DataReply         = 0x01, /* Response to DataRequest */
+	RSDataReply       = 0x02, /* Response to RSDataRequest */
+	Barrier           = 0x03,
+	ReportBitMap      = 0x04,
+	BecomeSyncTarget  = 0x05,
+	BecomeSyncSource  = 0x06,
+	UnplugRemote      = 0x07, /* Used at various times to hint the peer */
+	DataRequest       = 0x08, /* Used to ask for a data block */
+	RSDataRequest     = 0x09, /* Used to ask for a data block for resync */
+	SyncParam         = 0x0a,
+	ReportProtocol    = 0x0b,
+	ReportUUIDs       = 0x0c,
+	ReportSizes       = 0x0d,
+	ReportState       = 0x0e,
+	ReportSyncUUID    = 0x0f,
+	AuthChallenge     = 0x10,
+	AuthResponse      = 0x11,
+	StateChgRequest   = 0x12,
+
+	/* asender (meta socket */
+	Ping              = 0x13,
+	PingAck           = 0x14,
+	RecvAck           = 0x15, /* Used in protocol B */
+	WriteAck          = 0x16, /* Used in protocol C */
+	RSWriteAck        = 0x17, /* Is a WriteAck, additionally call set_in_sync(). */
+	DiscardAck        = 0x18, /* Used in proto C, two-primaries conflict detection */
+	NegAck            = 0x19, /* Sent if local disk is unusable */
+	NegDReply         = 0x1a, /* Local disk is broken... */
+	NegRSDReply       = 0x1b, /* Local disk is broken... */
+	BarrierAck        = 0x1c,
+	StateChgReply     = 0x1d,
+
+	/* "new" commands, no longer fitting into the ordering scheme above */
+
+	OVRequest         = 0x1e, /* data socket */
+	OVReply           = 0x1f,
+	OVResult          = 0x20, /* meta socket */
+	CsumRSRequest     = 0x21, /* data socket */
+	RSIsInSync        = 0x22, /* meta socket */
+	SyncParam89       = 0x23, /* data socket, protocol version 89 replacement for SyncParam */
+	ReportCBitMap     = 0x24, /* compressed or otherwise encoded bitmap transfer */
+
+	MAX_CMD           = 0x25,
+	MayIgnore         = 0x100, /* Flag to test if (cmd > MayIgnore) ... */
+	MAX_OPT_CMD       = 0x101,
+
+	/* special command ids for handshake */
+
+	HandShakeM        = 0xfff1, /* First Packet on the MetaSock */
+	HandShakeS        = 0xfff2, /* First Packet on the Socket */
+
+	HandShake         = 0xfffe  /* FIXED for the next century! */
+};
+
+static inline const char *cmdname(enum Drbd_Packet_Cmd cmd)
+{
+	/* THINK may need to become several global tables
+	 * when we want to support more than
+	 * one PRO_VERSION */
+	static const char *cmdnames[] = {
+		[Data]		   = "Data",
+		[DataReply]	   = "DataReply",
+		[RSDataReply]	   = "RSDataReply",
+		[Barrier]	   = "Barrier",
+		[ReportBitMap]	   = "ReportBitMap",
+		[BecomeSyncTarget] = "BecomeSyncTarget",
+		[BecomeSyncSource] = "BecomeSyncSource",
+		[UnplugRemote]	   = "UnplugRemote",
+		[DataRequest]	   = "DataRequest",
+		[RSDataRequest]    = "RSDataRequest",
+		[SyncParam]	   = "SyncParam",
+		[SyncParam89]	   = "SyncParam89",
+		[ReportProtocol]   = "ReportProtocol",
+		[ReportUUIDs]	   = "ReportUUIDs",
+		[ReportSizes]	   = "ReportSizes",
+		[ReportState]	   = "ReportState",
+		[ReportSyncUUID]   = "ReportSyncUUID",
+		[AuthChallenge]    = "AuthChallenge",
+		[AuthResponse]	   = "AuthResponse",
+		[Ping]		   = "Ping",
+		[PingAck]	   = "PingAck",
+		[RecvAck]	   = "RecvAck",
+		[WriteAck]	   = "WriteAck",
+		[RSWriteAck]	   = "RSWriteAck",
+		[DiscardAck]	   = "DiscardAck",
+		[NegAck]	   = "NegAck",
+		[NegDReply]	   = "NegDReply",
+		[NegRSDReply]	   = "NegRSDReply",
+		[BarrierAck]	   = "BarrierAck",
+		[StateChgRequest]  = "StateChgRequest",
+		[StateChgReply]    = "StateChgReply",
+		[OVRequest]        = "OVRequest",
+		[OVReply]          = "OVReply",
+		[OVResult]         = "OVResult",
+		[CsumRSRequest]    = "CsumRSRequest",
+		[RSIsInSync]       = "RSIsInSync",
+		[ReportCBitMap]    = "ReportCBitMap",
+		[MAX_CMD]	   = NULL,
+	};
+
+	if (cmd == HandShakeM)
+		return "HandShakeM";
+	if (cmd == HandShakeS)
+		return "HandShakeS";
+	if (cmd == HandShake)
+		return "HandShake";
+	if (cmd >= MAX_CMD)
+		return "Unknown";
+	return cmdnames[cmd];
+}
+
+/* for sending/receiving the bitmap,
+ * possibly in some encoding scheme */
+struct bm_xfer_ctx {
+	/* "const"
+	 * stores total bits and long words
+	 * of the bitmap, so we don't need to
+	 * call the accessor functions over and again. */
+	unsigned long bm_bits;
+	unsigned long bm_words;
+	/* during xfer, current position within the bitmap */
+	unsigned long bit_offset;
+	unsigned long word_offset;
+
+	/* statistics; index: (h->command == ReportBitMap) */
+	unsigned packets[2];
+	unsigned bytes[2];
+};
+
+extern void INFO_bm_xfer_stats(struct drbd_conf *mdev,
+		const char *direction, struct bm_xfer_ctx *c);
+
+static inline void bm_xfer_ctx_bit_to_word_offset(struct bm_xfer_ctx *c)
+{
+	/* word_offset counts "native long words" (32 or 64 bit),
+	 * aligned at 64 bit.
+	 * Encoded packet may end at an unaligned bit offset.
+	 * In case a fallback clear text packet is transmitted in
+	 * between, we adjust this offset back to the last 64bit
+	 * aligned "native long word", which makes coding and decoding
+	 * the plain text bitmap much more convenient.  */
+#if BITS_PER_LONG == 64
+	c->word_offset = c->bit_offset >> 6;
+#elif BITS_PER_LONG == 32
+	c->word_offset = c->bit_offset >> 5;
+	c->word_offset &= ~(1UL);
+#else
+# error "unsupported BITS_PER_LONG"
+#endif
+}
+
+/* This is the layout for a packet on the wire.
+ * The byteorder is the network byte order.
+ *     (except block_id and barrier fields.
+ *	these are pointers to local structs
+ *	and have no relevance for the partner,
+ *	which just echoes them as received.)
+ *
+ * NOTE that the payload starts at a long aligned offset,
+ * regardless of 32 or 64 bit arch!
+ */
+struct Drbd_Header {
+	u32	  magic;
+	u16	  command;
+	u16	  length;	/* bytes of data after this header */
+	u8	  payload[0];
+} __attribute((packed));
+/* 8 bytes. packet FIXED for the next century! */
+
+/*
+ * short commands, packets without payload, plain Drbd_Header:
+ *   Ping
+ *   PingAck
+ *   BecomeSyncTarget
+ *   BecomeSyncSource
+ *   UnplugRemote
+ */
+
+/*
+ * commands with out-of-struct payload:
+ *   ReportBitMap    (no additional fields)
+ *   Data, DataReply (see Drbd_Data_Packet)
+ *   ReportCBitMap (see receive_compressed_bitmap)
+ */
+
+/* these defines must not be changed without changing the protocol version */
+#define DP_HARDBARRIER	      1
+#define DP_RW_SYNC	      2
+#define DP_MAY_SET_IN_SYNC    4
+
+struct Drbd_Data_Packet {
+	struct Drbd_Header head;
+	u64	    sector;    /* 64 bits sector number */
+	u64	    block_id;  /* to identify the request in protocol B&C */
+	u32	    seq_num;
+	u32	    dp_flags;
+} __attribute((packed));
+
+/*
+ * commands which share a struct:
+ *  Drbd_BlockAck_Packet:
+ *   RecvAck (proto B), WriteAck (proto C),
+ *   DiscardAck (proto C, two-primaries conflict detection)
+ *  Drbd_BlockRequest_Packet:
+ *   DataRequest, RSDataRequest
+ */
+struct Drbd_BlockAck_Packet {
+	struct Drbd_Header head;
+	u64	    sector;
+	u64	    block_id;
+	u32	    blksize;
+	u32	    seq_num;
+} __attribute((packed));
+
+
+struct Drbd_BlockRequest_Packet {
+	struct Drbd_Header head;
+	u64 sector;
+	u64 block_id;
+	u32 blksize;
+	u32 pad;	/* to multiple of 8 Byte */
+} __attribute((packed));
+
+/*
+ * commands with their own struct for additional fields:
+ *   HandShake
+ *   Barrier
+ *   BarrierAck
+ *   SyncParam
+ *   ReportParams
+ */
+
+struct Drbd_HandShake_Packet {
+	struct Drbd_Header head;	/* 8 bytes */
+	u32 protocol_min;
+	u32 feature_flags;
+	u32 protocol_max;
+
+	/* should be more than enough for future enhancements
+	 * for now, feature_flags and the reserverd array shall be zero.
+	 */
+
+	u32 _pad;
+	u64 reserverd[7];
+} __attribute((packed));
+/* 80 bytes, FIXED for the next century */
+
+struct Drbd_Barrier_Packet {
+	struct Drbd_Header head;
+	u32 barrier;	/* barrier number _handle_ only */
+	u32 pad;	/* to multiple of 8 Byte */
+} __attribute((packed));
+
+struct Drbd_BarrierAck_Packet {
+	struct Drbd_Header head;
+	u32 barrier;
+	u32 set_size;
+} __attribute((packed));
+
+struct Drbd_SyncParam_Packet {
+	struct Drbd_Header head;
+	u32 rate;
+
+	      /* Since protocol version 88 and higher. */
+	char verify_alg[0];
+} __attribute((packed));
+
+struct Drbd_SyncParam89_Packet {
+	struct Drbd_Header head;
+	u32 rate;
+        /* protocol version 89: */
+	char verify_alg[SHARED_SECRET_MAX];
+	char csums_alg[SHARED_SECRET_MAX];
+} __attribute((packed));
+
+struct Drbd_Protocol_Packet {
+	struct Drbd_Header head;
+	u32 protocol;
+	u32 after_sb_0p;
+	u32 after_sb_1p;
+	u32 after_sb_2p;
+	u32 want_lose;
+	u32 two_primaries;
+
+              /* Since protocol version 87 and higher. */
+	char integrity_alg[0];
+
+} __attribute((packed));
+
+struct Drbd_GenCnt_Packet {
+	struct Drbd_Header head;
+	u64 uuid[EXT_UUID_SIZE];
+} __attribute((packed));
+
+struct Drbd_SyncUUID_Packet {
+	struct Drbd_Header head;
+	u64	    uuid;
+} __attribute((packed));
+
+struct Drbd_Sizes_Packet {
+	struct Drbd_Header head;
+	u64	    d_size;  /* size of disk */
+	u64	    u_size;  /* user requested size */
+	u64	    c_size;  /* current exported size */
+	u32	    max_segment_size;  /* Maximal size of a BIO */
+	u32	    queue_order_type;
+} __attribute((packed));
+
+struct Drbd_State_Packet {
+	struct Drbd_Header head;
+	u32	    state;
+} __attribute((packed));
+
+struct Drbd_Req_State_Packet {
+	struct Drbd_Header head;
+	u32	    mask;
+	u32	    val;
+} __attribute((packed));
+
+struct Drbd_RqS_Reply_Packet {
+	struct Drbd_Header head;
+	u32	    retcode;
+} __attribute((packed));
+
+struct Drbd06_Parameter_P {
+	u64	  size;
+	u32	  state;
+	u32	  blksize;
+	u32	  protocol;
+	u32	  version;
+	u32	  gen_cnt[5];
+	u32	  bit_map_gen[5];
+} __attribute((packed));
+
+struct Drbd_Discard_Packet {
+	struct Drbd_Header head;
+	u64	    block_id;
+	u32	    seq_num;
+	u32	    pad;
+} __attribute((packed));
+
+/* Valid values for the encoding field.
+ * Bump proto version when changing this. */
+enum Drbd_bitmap_code {
+	RLE_VLI_Bytes = 0,
+	RLE_VLI_BitsFibD_0_1 = 1,
+	RLE_VLI_BitsFibD_1_1 = 2,
+	RLE_VLI_BitsFibD_1_2 = 3,
+	RLE_VLI_BitsFibD_2_3 = 4,
+	RLE_VLI_BitsFibD_3_5 = 5,
+};
+
+struct Drbd_Compressed_Bitmap_Packet {
+	struct Drbd_Header 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
+	 * used to pad up to head.length bytes
+	 */
+	u8 encoding;
+
+	u8 code[0];
+} __attribute((packed));
+
+static inline enum Drbd_bitmap_code
+DCBP_get_code(struct Drbd_Compressed_Bitmap_Packet *p)
+{
+	return (enum Drbd_bitmap_code)(p->encoding & 0x0f);
+}
+
+static inline void
+DCBP_set_code(struct Drbd_Compressed_Bitmap_Packet *p, enum Drbd_bitmap_code code)
+{
+	BUG_ON(code & ~0xf);
+	p->encoding = (p->encoding & ~0xf) | code;
+}
+
+static inline int
+DCBP_get_start(struct Drbd_Compressed_Bitmap_Packet *p)
+{
+	return (p->encoding & 0x80) != 0;
+}
+
+static inline void
+DCBP_set_start(struct Drbd_Compressed_Bitmap_Packet *p, int set)
+{
+	p->encoding = (p->encoding & ~0x80) | (set ? 0x80 : 0);
+}
+
+static inline int
+DCBP_get_pad_bits(struct Drbd_Compressed_Bitmap_Packet *p)
+{
+	return (p->encoding >> 4) & 0x7;
+}
+
+static inline void
+DCBP_set_pad_bits(struct Drbd_Compressed_Bitmap_Packet *p, int n)
+{
+	BUG_ON(n & ~0x7);
+	p->encoding = (p->encoding & (~0x7 << 4)) | (n << 4);
+}
+
+/* one bitmap packet, including the Drbd_Header,
+ * should fit within one _architecture independend_ page.
+ * 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 Drbd_Header))
+#define BM_PACKET_WORDS (BM_PACKET_PAYLOAD_BYTES/sizeof(long))
+#define BM_PACKET_VLI_BYTES_MAX (4096 - sizeof(struct Drbd_Compressed_Bitmap_Packet))
+#if (PAGE_SIZE < 4096)
+/* drbd_send_bitmap / receive_bitmap would break horribly */
+#error "PAGE_SIZE too small"
+#endif
+
+union Drbd_Polymorph_Packet {
+	struct Drbd_Header		head;
+	struct Drbd_HandShake_Packet	HandShake;
+	struct Drbd_Data_Packet		Data;
+	struct Drbd_BlockAck_Packet	BlockAck;
+	struct Drbd_Barrier_Packet	Barrier;
+	struct Drbd_BarrierAck_Packet	BarrierAck;
+	struct Drbd_SyncParam89_Packet	SyncParam89;
+	struct Drbd_Protocol_Packet	Protocol;
+	struct Drbd_Sizes_Packet	Sizes;
+	struct Drbd_GenCnt_Packet	GenCnt;
+	struct Drbd_State_Packet	State;
+	struct Drbd_Req_State_Packet	ReqState;
+	struct Drbd_RqS_Reply_Packet	RqSReply;
+	struct Drbd_BlockRequest_Packet	BlockRequest;
+} __attribute((packed));
+
+/**********************************************************************/
+enum Drbd_thread_state {
+	None,
+	Running,
+	Exiting,
+	Restarting
+};
+
+struct Drbd_thread {
+	spinlock_t t_lock;
+	struct task_struct *task;
+	struct completion stop;
+	enum Drbd_thread_state t_state;
+	int (*function) (struct Drbd_thread *);
+	struct drbd_conf *mdev;
+	int reset_cpu_mask;
+};
+
+static inline enum Drbd_thread_state get_t_state(struct Drbd_thread *thi)
+{
+	/* THINK testing the t_state seems to be uncritical in all cases
+	 * (but thread_{start,stop}), so we can read it *without* the lock.
+	 *	--lge */
+
+	smp_rmb();
+	return thi->t_state;
+}
+
+
+/*
+ * Having this as the first member of a struct provides sort of "inheritance".
+ * "derived" structs can be "drbd_queue_work()"ed.
+ * The callback should know and cast back to the descendant struct.
+ * drbd_request and Tl_epoch_entry are descendants of drbd_work.
+ */
+struct drbd_work;
+typedef int (*drbd_work_cb)(struct drbd_conf *, struct drbd_work *, int cancel);
+struct drbd_work {
+	struct list_head list;
+	drbd_work_cb cb;
+};
+
+struct drbd_barrier;
+struct drbd_request {
+	struct drbd_work w;
+	struct drbd_conf *mdev;
+	struct bio *private_bio;
+	struct hlist_node colision;
+	sector_t sector;
+	unsigned int size;
+	unsigned int epoch; /* barrier_nr */
+
+	/* barrier_nr: used to check on "completion" whether this req was in
+	 * the current epoch, and we therefore have to close it,
+	 * starting a new epoch...
+	 */
+
+	/* up to here, the struct layout is identical to Tl_epoch_entry;
+	 * we might be able to use that to our advantage...  */
+
+	struct list_head tl_requests; /* ring list in the transfer log */
+	struct bio *master_bio;       /* master bio pointer */
+	unsigned long rq_state; /* see comments above _req_mod() */
+	int seq_num;
+	unsigned long start_time;
+};
+
+struct drbd_barrier {
+	struct drbd_work w;
+	struct list_head requests; /* requests before */
+	struct drbd_barrier *next; /* pointer to the next barrier */
+	unsigned int br_number;  /* the barriers identifier. */
+	int n_req;	/* number of requests attached before this barrier */
+};
+
+struct drbd_request;
+
+/* These Tl_epoch_entries may be in one of 6 lists:
+   active_ee .. data packet being written
+   sync_ee   .. syncer block being written
+   done_ee   .. block written, need to send WriteAck
+   read_ee   .. [RS]DataRequest being read
+*/
+
+struct drbd_epoch {
+	struct list_head list;
+	unsigned int barrier_nr;
+	atomic_t epoch_size; /* increased on every request added. */
+	atomic_t active;     /* increased on every req. added, and dec on every finished. */
+	unsigned long flags;
+};
+
+/* drbd_epoch flag bits */
+enum {
+	DE_BARRIER_IN_NEXT_EPOCH_ISSUED,
+	DE_BARRIER_IN_NEXT_EPOCH_DONE,
+	DE_CONTAINS_A_BARRIER,
+	DE_HAVE_BARRIER_NUMBER,
+	DE_IS_FINISHING,
+};
+
+struct Tl_epoch_entry {
+	struct drbd_work    w;
+	struct drbd_conf *mdev;
+	struct bio *private_bio;
+	struct hlist_node colision;
+	sector_t sector;
+	unsigned int size;
+	struct drbd_epoch *epoch;
+
+	/* up to here, the struct layout is identical to drbd_request;
+	 * we might be able to use that to our advantage...  */
+
+	unsigned int flags;
+	u64    block_id;
+};
+
+struct digest_info {
+	int digest_size;
+	void *digest;
+};
+
+/* ee flag bits */
+enum {
+	__EE_CALL_AL_COMPLETE_IO,
+	__EE_CONFLICT_PENDING,
+	__EE_MAY_SET_IN_SYNC,
+	__EE_IS_BARRIER,
+};
+#define EE_CALL_AL_COMPLETE_IO (1<<__EE_CALL_AL_COMPLETE_IO)
+#define EE_CONFLICT_PENDING    (1<<__EE_CONFLICT_PENDING)
+#define EE_MAY_SET_IN_SYNC     (1<<__EE_MAY_SET_IN_SYNC)
+#define EE_IS_BARRIER          (1<<__EE_IS_BARRIER)
+
+/* global flag bits */
+enum {
+	CREATE_BARRIER,		/* next Data is preceeded by a Barrier */
+	SIGNAL_ASENDER,		/* whether asender wants to be interrupted */
+	SEND_PING,		/* whether asender should send a ping asap */
+	WORK_PENDING,		/* completion flag for drbd_disconnect */
+	STOP_SYNC_TIMER,	/* tell timer to cancel itself */
+	UNPLUG_QUEUED,		/* only relevant with kernel 2.4 */
+	UNPLUG_REMOTE,		/* sending a "UnplugRemote" could help */
+	MD_DIRTY,		/* current uuids and flags not yet on disk */
+	DISCARD_CONCURRENT,	/* Set on one node, cleared on the peer! */
+	USE_DEGR_WFC_T,		/* degr-wfc-timeout instead of wfc-timeout. */
+	CLUSTER_ST_CHANGE,	/* Cluster wide state change going on... */
+	CL_ST_CHG_SUCCESS,
+	CL_ST_CHG_FAIL,
+	CRASHED_PRIMARY,	/* This node was a crashed primary.
+				 * Gets cleared when the state.conn
+				 * goes into Connected state. */
+	WRITE_BM_AFTER_RESYNC,	/* A kmalloc() during resync failed */
+	NO_BARRIER_SUPP,	/* underlying block device doesn't implement barriers */
+	CONSIDER_RESYNC,
+
+	MD_NO_BARRIER,		/* meta data device does not support barriers,
+				   so don't even try */
+	SUSPEND_IO,		/* suspend application io */
+	BITMAP_IO,		/* suspend application io;
+				   once no more io in flight, start bitmap io */
+	BITMAP_IO_QUEUED,       /* Started bitmap IO */
+	RESYNC_AFTER_NEG,       /* Resync after online grow after the attach&negotiate finished. */
+	NET_CONGESTED,		/* The data socket is congested */
+};
+
+struct drbd_bitmap; /* opaque for drbd_conf */
+
+/* TODO sort members for performance
+ * MAYBE group them further */
+
+/* THINK maybe we actually want to use the default "event/%s" worker threads
+ * or similar in linux 2.6, which uses per cpu data and threads.
+ *
+ * To be general, this might need a spin_lock member.
+ * For now, please use the mdev->req_lock to protect list_head,
+ * see drbd_queue_work below.
+ */
+struct drbd_work_queue {
+	struct list_head q;
+	struct semaphore s; /* producers up it, worker down()s it */
+	spinlock_t q_lock;  /* to protect the list. */
+};
+
+struct drbd_socket {
+	struct drbd_work_queue work;
+	struct mutex mutex;
+	struct socket    *socket;
+	/* this way we get our
+	 * send/receive buffers off the stack */
+	union Drbd_Polymorph_Packet sbuf;
+	union Drbd_Polymorph_Packet rbuf;
+};
+
+struct drbd_md {
+	u64 md_offset;		/* sector offset to 'super' block */
+
+	u64 la_size_sect;	/* last agreed size, unit sectors */
+	u64 uuid[UUID_SIZE];
+	u64 device_uuid;
+	u32 flags;
+	u32 md_size_sect;
+
+	s32 al_offset;	/* signed relative sector offset to al area */
+	s32 bm_offset;	/* signed relative sector offset to bitmap */
+
+	/* u32 al_nr_extents;	   important for restoring the AL
+	 * is stored into  sync_conf.al_extents, which in turn
+	 * gets applied to act_log->nr_elements
+	 */
+};
+
+/* for sync_conf and other types... */
+#define NL_PACKET(name, number, fields) struct name { fields };
+#define NL_INTEGER(pn,pr,member) int member;
+#define NL_INT64(pn,pr,member) __u64 member;
+#define NL_BIT(pn,pr,member)   unsigned member:1;
+#define NL_STRING(pn,pr,member,len) unsigned char member[len]; int member ## _len;
+#include "linux/drbd_nl.h"
+
+struct drbd_backing_dev {
+	struct block_device *backing_bdev;
+	struct block_device *md_bdev;
+	struct file *lo_file;
+	struct file *md_file;
+	struct drbd_md md;
+	struct disk_conf dc; /* The user provided config... */
+	sector_t known_size; /* last known size of that backing device */
+};
+
+struct drbd_md_io {
+	struct drbd_conf *mdev;
+	struct completion event;
+	int error;
+};
+
+struct bm_io_work {
+	struct drbd_work w;
+	char *why;
+	int (*io_fn)(struct drbd_conf *mdev);
+	void (*done)(struct drbd_conf *mdev, int rv);
+};
+
+enum write_ordering_e {
+	WO_none,
+	WO_drain_io,
+	WO_bdev_flush,
+	WO_bio_barrier
+};
+
+struct drbd_conf {
+	/* things that are stored as / read from meta data on disk */
+	unsigned long flags;
+
+	/* configured by drbdsetup */
+	struct net_conf *net_conf; /* protected by inc_net() and dec_net() */
+	struct syncer_conf sync_conf;
+	struct drbd_backing_dev *bc __protected_by(local);
+
+	sector_t p_size;     /* partner's disk size */
+	struct request_queue *rq_queue;
+	struct block_device *this_bdev;
+	struct gendisk	    *vdisk;
+
+	struct drbd_socket data; /* data/barrier/cstate/parameter packets */
+	struct drbd_socket meta; /* ping/ack (metadata) packets */
+	int agreed_pro_version;  /* actually used protocol version */
+	unsigned long last_received; /* in jiffies, either socket */
+	unsigned int ko_count;
+	struct drbd_work  resync_work,
+			  unplug_work,
+			  md_sync_work;
+	struct timer_list resync_timer;
+	struct timer_list md_sync_timer;
+
+	/* Used after attach while negotiating new disk state. */
+	union drbd_state_t new_state_tmp;
+
+	union drbd_state_t state;
+	wait_queue_head_t misc_wait;
+	wait_queue_head_t state_wait;  /* upon each state change. */
+	unsigned int send_cnt;
+	unsigned int recv_cnt;
+	unsigned int read_cnt;
+	unsigned int writ_cnt;
+	unsigned int al_writ_cnt;
+	unsigned int bm_writ_cnt;
+	atomic_t ap_bio_cnt;	 /* Requests we need to complete */
+	atomic_t ap_pending_cnt; /* AP data packets on the wire, ack expected */
+	atomic_t rs_pending_cnt; /* RS request/data packets on the wire */
+	atomic_t unacked_cnt;	 /* Need to send replys for */
+	atomic_t local_cnt;	 /* Waiting for local completion */
+	atomic_t net_cnt;	 /* Users of net_conf */
+	spinlock_t req_lock;
+	struct drbd_barrier *unused_spare_barrier; /* for pre-allocation */
+	struct drbd_barrier *newest_barrier;
+	struct drbd_barrier *oldest_barrier;
+	struct list_head out_of_sequence_requests;
+	struct hlist_head *tl_hash;
+	unsigned int tl_hash_s;
+
+	/* blocks to sync in this run [unit BM_BLOCK_SIZE] */
+	unsigned long rs_total;
+	/* number of sync IOs that failed in this run */
+	unsigned long rs_failed;
+	/* Syncer's start time [unit jiffies] */
+	unsigned long rs_start;
+	/* cumulated time in PausedSyncX state [unit jiffies] */
+	unsigned long rs_paused;
+	/* block not up-to-date at mark [unit BM_BLOCK_SIZE] */
+	unsigned long rs_mark_left;
+	/* marks's time [unit jiffies] */
+	unsigned long rs_mark_time;
+	/* skipped because csum was equeal [unit BM_BLOCK_SIZE] */
+	unsigned long rs_same_csum;
+	sector_t ov_position;
+	/* Start sector of out of sync range. */
+	sector_t ov_last_oos_start;
+	/* size of out-of-sync range in sectors. */
+	sector_t ov_last_oos_size;
+	unsigned long ov_left;
+	struct crypto_hash *csums_tfm;
+	struct crypto_hash *verify_tfm;
+
+	struct Drbd_thread receiver;
+	struct Drbd_thread worker;
+	struct Drbd_thread asender;
+	struct drbd_bitmap *bitmap;
+	unsigned long bm_resync_fo; /* bit offset for drbd_bm_find_next */
+
+	/* Used to track operations of resync... */
+	struct lru_cache *resync;
+	/* Number of locked elements in resync LRU */
+	unsigned int resync_locked;
+	/* resync extent number waiting for application requests */
+	unsigned int resync_wenr;
+
+	int open_cnt;
+	u64 *p_uuid;
+	struct drbd_epoch *current_epoch;
+	spinlock_t epoch_lock;
+	unsigned int epochs;
+	enum write_ordering_e write_ordering;
+	struct list_head active_ee; /* IO in progress */
+	struct list_head sync_ee;   /* IO in progress */
+	struct list_head done_ee;   /* send ack */
+	struct list_head read_ee;   /* IO in progress */
+	struct list_head net_ee;    /* zero-copy network send in progress */
+	struct hlist_head *ee_hash; /* is proteced by req_lock! */
+	unsigned int ee_hash_s;
+
+	/* this one is protected by ee_lock, single thread */
+	struct Tl_epoch_entry *last_write_w_barrier;
+
+	int next_barrier_nr;
+	struct hlist_head *app_reads_hash; /* is proteced by req_lock */
+	struct list_head resync_reads;
+	atomic_t pp_in_use;
+	wait_queue_head_t ee_wait;
+	struct page *md_io_page;	/* one page buffer for md_io */
+	struct page *md_io_tmpp;	/* for hardsect != 512 [s390 only?] */
+	struct mutex md_io_mutex;	/* protects the md_io_buffer */
+	spinlock_t al_lock;
+	wait_queue_head_t al_wait;
+	struct lru_cache *act_log;	/* activity log */
+	unsigned int al_tr_number;
+	int al_tr_cycle;
+	int al_tr_pos;   /* position of the next transaction in the journal */
+	struct crypto_hash *cram_hmac_tfm;
+	struct crypto_hash *integrity_w_tfm; /* to be used by the worker thread */
+	struct crypto_hash *integrity_r_tfm; /* to be used by the receiver thread */
+	void *int_dig_out;
+	void *int_dig_in;
+	void *int_dig_vv;
+	wait_queue_head_t seq_wait;
+	atomic_t packet_seq;
+	unsigned int peer_seq;
+	spinlock_t peer_seq_lock;
+	unsigned int minor;
+	unsigned long comm_bm_set; /* communicated number of set bits. */
+	cpumask_t cpu_mask;
+	struct bm_io_work bm_io_work;
+	u64 ed_uuid; /* UUID of the exposed data */
+	struct mutex state_mutex;
+	char congestion_reason;  /* Why we where congested... */
+};
+
+static inline struct drbd_conf *minor_to_mdev(unsigned int minor)
+{
+	struct drbd_conf *mdev;
+
+	mdev = minor < minor_count ? minor_table[minor] : NULL;
+
+	return mdev;
+}
+
+static inline unsigned int mdev_to_minor(struct drbd_conf *mdev)
+{
+	return mdev->minor;
+}
+
+/* returns 1 if it was successfull,
+ * returns 0 if there was no data socket.
+ * so wherever you are going to use the data.socket, e.g. do
+ * if (!drbd_get_data_sock(mdev))
+ *	return 0;
+ *	CODE();
+ * drbd_put_data_sock(mdev);
+ */
+static inline int drbd_get_data_sock(struct drbd_conf *mdev)
+{
+	mutex_lock(&mdev->data.mutex);
+	/* drbd_disconnect() could have called drbd_free_sock()
+	 * while we were waiting in down()... */
+	if (unlikely(mdev->data.socket == NULL)) {
+		mutex_unlock(&mdev->data.mutex);
+		return 0;
+	}
+	return 1;
+}
+
+static inline void drbd_put_data_sock(struct drbd_conf *mdev)
+{
+	mutex_unlock(&mdev->data.mutex);
+}
+
+/*
+ * function declarations
+ *************************/
+
+/* drbd_main.c */
+
+enum chg_state_flags {
+	ChgStateHard	= 1,
+	ChgStateVerbose = 2,
+	ChgWaitComplete = 4,
+	ChgSerialize    = 8,
+	ChgOrdered      = ChgWaitComplete + ChgSerialize,
+};
+
+extern void drbd_init_set_defaults(struct drbd_conf *mdev);
+extern int drbd_change_state(struct drbd_conf *mdev, enum chg_state_flags f,
+			union drbd_state_t mask, union drbd_state_t val);
+extern void drbd_force_state(struct drbd_conf *, union drbd_state_t,
+			union drbd_state_t);
+extern int _drbd_request_state(struct drbd_conf *, union drbd_state_t,
+			union drbd_state_t, enum chg_state_flags);
+extern int __drbd_set_state(struct drbd_conf *, union drbd_state_t,
+			    enum chg_state_flags, struct completion *done);
+extern void print_st_err(struct drbd_conf *, union drbd_state_t,
+			union drbd_state_t, int);
+extern int  drbd_thread_start(struct Drbd_thread *thi);
+extern void _drbd_thread_stop(struct Drbd_thread *thi, int restart, int wait);
+#ifdef CONFIG_SMP
+extern void drbd_thread_current_set_cpu(struct drbd_conf *mdev);
+extern cpumask_t drbd_calc_cpu_mask(struct drbd_conf *mdev);
+#else
+#define drbd_thread_current_set_cpu(A) ({})
+#define drbd_calc_cpu_mask(A) CPU_MASK_ALL
+#endif
+extern void drbd_free_resources(struct drbd_conf *mdev);
+extern void tl_release(struct drbd_conf *mdev, unsigned int barrier_nr,
+		       unsigned int set_size);
+extern void tl_clear(struct drbd_conf *mdev);
+extern void _tl_add_barrier(struct drbd_conf *, struct drbd_barrier *);
+extern void drbd_free_sock(struct drbd_conf *mdev);
+extern int drbd_send(struct drbd_conf *mdev, struct socket *sock,
+			void *buf, size_t size, unsigned msg_flags);
+extern int drbd_send_protocol(struct drbd_conf *mdev);
+extern int _drbd_send_uuids(struct drbd_conf *mdev);
+extern int drbd_send_uuids(struct drbd_conf *mdev);
+extern int drbd_send_sync_uuid(struct drbd_conf *mdev, u64 val);
+extern int drbd_send_sizes(struct drbd_conf *mdev);
+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_Packet_Cmd cmd, struct Drbd_Header *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_Packet_Cmd cmd, struct Drbd_Header *h,
+			size_t size);
+extern int drbd_send_cmd2(struct drbd_conf *mdev, enum Drbd_Packet_Cmd cmd,
+			char *data, size_t size);
+extern int drbd_send_sync_param(struct drbd_conf *mdev, struct syncer_conf *sc);
+extern int drbd_send_b_ack(struct drbd_conf *mdev, u32 barrier_nr,
+			u32 set_size);
+extern int drbd_send_ack(struct drbd_conf *mdev, enum Drbd_Packet_Cmd cmd,
+			struct Tl_epoch_entry *e);
+extern int drbd_send_ack_rp(struct drbd_conf *mdev, enum Drbd_Packet_Cmd cmd,
+			struct Drbd_BlockRequest_Packet *rp);
+extern int drbd_send_ack_dp(struct drbd_conf *mdev, enum Drbd_Packet_Cmd cmd,
+			struct Drbd_Data_Packet *dp);
+extern int drbd_send_ack_ex(struct drbd_conf *mdev, enum Drbd_Packet_Cmd cmd,
+			    sector_t sector, int blksize, u64 block_id);
+extern int _drbd_send_page(struct drbd_conf *mdev, struct page *page,
+			int offset, size_t size);
+extern int drbd_send_block(struct drbd_conf *mdev, enum Drbd_Packet_Cmd cmd,
+			   struct Tl_epoch_entry *e);
+extern int drbd_send_dblock(struct drbd_conf *mdev, struct drbd_request *req);
+extern int _drbd_send_barrier(struct drbd_conf *mdev,
+			struct drbd_barrier *barrier);
+extern int drbd_send_drequest(struct drbd_conf *mdev, int cmd,
+			      sector_t sector, int size, u64 block_id);
+extern int drbd_send_drequest_csum(struct drbd_conf *mdev,
+				   sector_t sector,int size,
+				   void *digest, int digest_size,
+				   enum Drbd_Packet_Cmd cmd);
+extern int drbd_send_ov_request(struct drbd_conf *mdev,sector_t sector,int size);
+
+extern int drbd_send_bitmap(struct drbd_conf *mdev);
+extern int _drbd_send_bitmap(struct drbd_conf *mdev);
+extern int drbd_send_sr_reply(struct drbd_conf *mdev, int retcode);
+extern void drbd_free_bc(struct drbd_backing_dev *bc);
+extern int drbd_io_error(struct drbd_conf *mdev, int forcedetach);
+extern void drbd_mdev_cleanup(struct drbd_conf *mdev);
+
+/* drbd_meta-data.c (still in drbd_main.c) */
+extern void drbd_md_sync(struct drbd_conf *mdev);
+extern int  drbd_md_read(struct drbd_conf *mdev, struct drbd_backing_dev *bdev);
+/* maybe define them below as inline? */
+extern void drbd_uuid_set(struct drbd_conf *mdev, int idx, u64 val) __must_hold(local);
+extern void _drbd_uuid_set(struct drbd_conf *mdev, int idx, u64 val) __must_hold(local);
+extern void drbd_uuid_new_current(struct drbd_conf *mdev) __must_hold(local);
+extern void _drbd_uuid_new_current(struct drbd_conf *mdev) __must_hold(local);
+extern void drbd_uuid_set_bm(struct drbd_conf *mdev, u64 val) __must_hold(local);
+extern void drbd_md_set_flag(struct drbd_conf *mdev, int flags) __must_hold(local);
+extern void drbd_md_clear_flag(struct drbd_conf *mdev, int flags)__must_hold(local);
+extern int drbd_md_test_flag(struct drbd_backing_dev *, int);
+extern void drbd_md_mark_dirty(struct drbd_conf *mdev);
+extern void drbd_queue_bitmap_io(struct drbd_conf *mdev,
+				 int (*io_fn)(struct drbd_conf *),
+				 void (*done)(struct drbd_conf *, int),
+				 char *why);
+extern int drbd_bmio_set_n_write(struct drbd_conf *mdev);
+extern int drbd_bmio_clear_n_write(struct drbd_conf *mdev);
+extern int drbd_bitmap_io(struct drbd_conf *mdev, int (*io_fn)(struct drbd_conf *), char *why);
+
+
+/* Meta data layout
+   We reserve a 128MB Block (4k aligned)
+   * either at the end of the backing device
+   * or on a seperate meta data device. */
+
+#define MD_RESERVED_SECT (128LU << 11)  /* 128 MB, unit sectors */
+/* The following numbers are sectors */
+#define MD_AL_OFFSET 8	    /* 8 Sectors after start of meta area */
+#define MD_AL_MAX_SIZE 64   /* = 32 kb LOG  ~ 3776 extents ~ 14 GB Storage */
+/* Allows up to about 3.8TB */
+#define MD_BM_OFFSET (MD_AL_OFFSET + MD_AL_MAX_SIZE)
+
+/* Since the smalles IO unit is usually 512 byte */
+#define MD_HARDSECT_B	 9
+#define MD_HARDSECT	 (1<<MD_HARDSECT_B)
+
+/* activity log */
+#define AL_EXTENTS_PT ((MD_HARDSECT-12)/8-1) /* 61 ; Extents per 512B sector */
+#define AL_EXTENT_SIZE_B 22		 /* One extent represents 4M Storage */
+#define AL_EXTENT_SIZE (1<<AL_EXTENT_SIZE_B)
+
+#if BITS_PER_LONG == 32
+#define LN2_BPL 5
+#define cpu_to_lel(A) cpu_to_le32(A)
+#define lel_to_cpu(A) le32_to_cpu(A)
+#elif BITS_PER_LONG == 64
+#define LN2_BPL 6
+#define cpu_to_lel(A) cpu_to_le64(A)
+#define lel_to_cpu(A) le64_to_cpu(A)
+#else
+#error "LN2 of BITS_PER_LONG unknown!"
+#endif
+
+/* resync bitmap */
+/* 16MB sized 'bitmap extent' to track syncer usage */
+struct bm_extent {
+	struct lc_element lce;
+	int rs_left; /* number of bits set (out of sync) in this extent. */
+	int rs_failed; /* number of failed resync requests in this extent. */
+	unsigned long flags;
+};
+
+#define BME_NO_WRITES  0  /* bm_extent.flags: no more requests on this one! */
+#define BME_LOCKED     1  /* bm_extent.flags: syncer active on this one. */
+
+/* drbd_bitmap.c */
+/*
+ * We need to store one bit for a block.
+ * Example: 1GB disk @ 4096 byte blocks ==> we need 32 KB bitmap.
+ * Bit 0 ==> local node thinks this block is binary identical on both nodes
+ * Bit 1 ==> local node thinks this block needs to be synced.
+ */
+
+#define BM_BLOCK_SIZE_B  12			 /* 4k per bit */
+#define BM_BLOCK_SIZE	 (1<<BM_BLOCK_SIZE_B)
+/* (9+3) : 512 bytes @ 8 bits; representing 16M storage
+ * per sector of on disk bitmap */
+#define BM_EXT_SIZE_B	 (BM_BLOCK_SIZE_B + MD_HARDSECT_B + 3)  /* = 24 */
+#define BM_EXT_SIZE	 (1<<BM_EXT_SIZE_B)
+
+#if (BM_EXT_SIZE_B != 24) || (BM_BLOCK_SIZE_B != 12)
+#error "HAVE YOU FIXED drbdmeta AS WELL??"
+#endif
+
+/* thus many _storage_ sectors are described by one bit */
+#define BM_SECT_TO_BIT(x)   ((x)>>(BM_BLOCK_SIZE_B-9))
+#define BM_BIT_TO_SECT(x)   ((sector_t)(x)<<(BM_BLOCK_SIZE_B-9))
+#define BM_SECT_PER_BIT     BM_BIT_TO_SECT(1)
+
+/* bit to represented kilo byte conversion */
+#define Bit2KB(bits) ((bits)<<(BM_BLOCK_SIZE_B-10))
+
+/* in which _bitmap_ extent (resp. sector) the bit for a certain
+ * _storage_ sector is located in */
+#define BM_SECT_TO_EXT(x)   ((x)>>(BM_EXT_SIZE_B-9))
+
+/* how much _storage_ sectors we have per bitmap sector */
+#define BM_EXT_TO_SECT(x)   ((sector_t)(x) << (BM_EXT_SIZE_B-9))
+#define BM_SECT_PER_EXT     BM_EXT_TO_SECT(1)
+
+/* in one sector of the bitmap, we have this many activity_log extents. */
+#define AL_EXT_PER_BM_SECT  (1 << (BM_EXT_SIZE_B - AL_EXTENT_SIZE_B))
+#define BM_WORDS_PER_AL_EXT (1 << (AL_EXTENT_SIZE_B-BM_BLOCK_SIZE_B-LN2_BPL))
+
+#define BM_BLOCKS_PER_BM_EXT_B (BM_EXT_SIZE_B - BM_BLOCK_SIZE_B)
+#define BM_BLOCKS_PER_BM_EXT_MASK  ((1<<BM_BLOCKS_PER_BM_EXT_B) - 1)
+
+/* the extent in "PER_EXTENT" below is an activity log extent
+ * we need that many (long words/bytes) to store the bitmap
+ *		     of one AL_EXTENT_SIZE chunk of storage.
+ * we can store the bitmap for that many AL_EXTENTS within
+ * one sector of the _on_disk_ bitmap:
+ * bit	 0	  bit 37   bit 38	     bit (512*8)-1
+ *	     ...|........|........|.. // ..|........|
+ * sect. 0	 `296	  `304			   ^(512*8*8)-1
+ *
+#define BM_WORDS_PER_EXT    ( (AL_EXT_SIZE/BM_BLOCK_SIZE) / BITS_PER_LONG )
+#define BM_BYTES_PER_EXT    ( (AL_EXT_SIZE/BM_BLOCK_SIZE) / 8 )  // 128
+#define BM_EXT_PER_SECT	    ( 512 / BM_BYTES_PER_EXTENT )	 //   4
+ */
+
+#define DRBD_MAX_SECTORS_32 (0xffffffffLU)
+#define DRBD_MAX_SECTORS_BM \
+	  ((MD_RESERVED_SECT - MD_BM_OFFSET) * (1LL<<(BM_EXT_SIZE_B-9)))
+#if DRBD_MAX_SECTORS_BM < DRBD_MAX_SECTORS_32
+#define DRBD_MAX_SECTORS      DRBD_MAX_SECTORS_BM
+#define DRBD_MAX_SECTORS_FLEX DRBD_MAX_SECTORS_BM
+#elif !defined(CONFIG_LBD) && BITS_PER_LONG == 32
+#define DRBD_MAX_SECTORS      DRBD_MAX_SECTORS_32
+#define DRBD_MAX_SECTORS_FLEX DRBD_MAX_SECTORS_32
+#else
+#define DRBD_MAX_SECTORS      DRBD_MAX_SECTORS_BM
+/* 16 TB in units of sectors */
+#if BITS_PER_LONG == 32
+/* adjust by one page worth of bitmap,
+ * so we won't wrap around in drbd_bm_find_next_bit.
+ * you should use 64bit OS for that much storage, anyways. */
+#define DRBD_MAX_SECTORS_FLEX BM_BIT_TO_SECT(0xffff7fff)
+#else
+#define DRBD_MAX_SECTORS_FLEX BM_BIT_TO_SECT(0x1LU << 32)
+#endif
+#endif
+
+/* Sector shift value for the "hash" functions of tl_hash and ee_hash tables.
+ * With a value of 6 all IO in one 32K block make it to the same slot of the
+ * hash table. */
+#define HT_SHIFT 6
+#define DRBD_MAX_SEGMENT_SIZE (1U<<(9+HT_SHIFT))
+
+/* Number of elements in the app_reads_hash */
+#define APP_R_HSIZE 15
+
+extern int  drbd_bm_init(struct drbd_conf *mdev);
+extern int  drbd_bm_resize(struct drbd_conf *mdev, sector_t sectors);
+extern void drbd_bm_cleanup(struct drbd_conf *mdev);
+extern void drbd_bm_set_all(struct drbd_conf *mdev);
+extern void drbd_bm_clear_all(struct drbd_conf *mdev);
+extern int  drbd_bm_set_bits(
+		struct drbd_conf *mdev, unsigned long s, unsigned long e);
+extern int  drbd_bm_clear_bits(
+		struct drbd_conf *mdev, unsigned long s, unsigned long e);
+/* bm_set_bits variant for use while holding drbd_bm_lock */
+extern int _drbd_bm_set_bits(struct drbd_conf *mdev,
+		const unsigned long s, const unsigned long e);
+extern int  drbd_bm_test_bit(struct drbd_conf *mdev, unsigned long bitnr);
+extern int  drbd_bm_e_weight(struct drbd_conf *mdev, unsigned long enr);
+extern int  drbd_bm_write_sect(struct drbd_conf *mdev, unsigned long enr) __must_hold(local);
+extern int  drbd_bm_read(struct drbd_conf *mdev) __must_hold(local);
+extern int  drbd_bm_write(struct drbd_conf *mdev) __must_hold(local);
+extern unsigned long drbd_bm_ALe_set_all(struct drbd_conf *mdev,
+		unsigned long al_enr);
+extern size_t	     drbd_bm_words(struct drbd_conf *mdev);
+extern unsigned long drbd_bm_bits(struct drbd_conf *mdev);
+extern sector_t      drbd_bm_capacity(struct drbd_conf *mdev);
+extern unsigned long drbd_bm_find_next(struct drbd_conf *mdev, unsigned long bm_fo);
+/* bm_find_next variants for use while you hold drbd_bm_lock() */
+extern unsigned long _drbd_bm_find_next(struct drbd_conf *mdev, unsigned long bm_fo);
+extern unsigned long _drbd_bm_find_next_zero(struct drbd_conf *mdev, unsigned long bm_fo);
+extern unsigned long drbd_bm_total_weight(struct drbd_conf *mdev);
+extern int drbd_bm_rs_done(struct drbd_conf *mdev);
+/* for receive_bitmap */
+extern void drbd_bm_merge_lel(struct drbd_conf *mdev, size_t offset,
+		size_t number, unsigned long *buffer);
+/* for _drbd_send_bitmap and drbd_bm_write_sect */
+extern void drbd_bm_get_lel(struct drbd_conf *mdev, size_t offset,
+		size_t number, unsigned long *buffer);
+
+extern void drbd_bm_lock(struct drbd_conf *mdev, char *why);
+extern void drbd_bm_unlock(struct drbd_conf *mdev);
+
+extern void _drbd_bm_recount_bits(struct drbd_conf *mdev, char *file, int line);
+#define drbd_bm_recount_bits(mdev) \
+	_drbd_bm_recount_bits(mdev, __FILE__, __LINE__)
+extern int drbd_bm_count_bits(struct drbd_conf *mdev, const unsigned long s, const unsigned long e);
+/* drbd_main.c */
+
+extern struct kmem_cache *drbd_request_cache;
+extern struct kmem_cache *drbd_ee_cache;
+extern mempool_t *drbd_request_mempool;
+extern mempool_t *drbd_ee_mempool;
+
+extern struct page *drbd_pp_pool; /* drbd's page pool */
+extern spinlock_t   drbd_pp_lock;
+extern int	    drbd_pp_vacant;
+extern wait_queue_head_t drbd_pp_wait;
+
+extern rwlock_t global_state_lock;
+
+extern struct drbd_conf *drbd_new_device(unsigned int minor);
+extern void drbd_free_mdev(struct drbd_conf *mdev);
+
+/* Dynamic tracing framework */
+#ifdef ENABLE_DYNAMIC_TRACE
+
+extern int proc_details;
+extern int trace_type;
+extern int trace_devs;
+extern int trace_level;
+
+enum {
+	TraceLvlAlways = 0,
+	TraceLvlSummary,
+	TraceLvlMetrics,
+	TraceLvlAll,
+	TraceLvlMax
+};
+
+enum {
+	TraceTypePacket = 0x00000001,
+	TraceTypeRq	= 0x00000002,
+	TraceTypeUuid	= 0x00000004,
+	TraceTypeResync = 0x00000008,
+	TraceTypeEE	= 0x00000010,
+	TraceTypeUnplug = 0x00000020,
+	TraceTypeNl	= 0x00000040,
+	TraceTypeALExts = 0x00000080,
+	TraceTypeIntRq  = 0x00000100,
+	TraceTypeMDIO   = 0x00000200,
+	TraceTypeEpochs = 0x00000400,
+};
+
+static inline int
+is_trace(unsigned int type, unsigned int level) {
+	return (trace_level >= level) && (type & trace_type);
+}
+static inline int
+is_mdev_trace(struct drbd_conf *mdev, unsigned int type, unsigned int level) {
+	return is_trace(type, level) &&
+		((1 << mdev_to_minor(mdev)) & trace_devs);
+}
+
+#define MTRACE(type, lvl, code...) \
+do { \
+	if (unlikely(is_mdev_trace(mdev, type, lvl))) { \
+		code \
+	} \
+} while (0)
+
+#define TRACE(type, lvl, code...) \
+do { \
+	if (unlikely(is_trace(type, lvl))) { \
+		code \
+	} \
+} while (0)
+
+/* Buffer printing support
+ * dbg_print_flags: used for Flags arg to drbd_print_buffer
+ * - DBGPRINT_BUFFADDR; if set, each line starts with the
+ *	 virtual address of the line being output. If clear,
+ *	 each line starts with the offset from the beginning
+ *	 of the buffer. */
+enum dbg_print_flags {
+    DBGPRINT_BUFFADDR = 0x0001,
+};
+
+extern void drbd_print_uuid(struct drbd_conf *mdev, unsigned int idx);
+
+extern void drbd_print_buffer(const char *prefix, unsigned int flags, int size,
+			      const void *buffer, const void *buffer_va,
+			      unsigned int length);
+
+/* Bio printing support */
+extern void _dump_bio(const char *pfx, struct drbd_conf *mdev, struct bio *bio, int complete, struct drbd_request *r);
+
+static inline void dump_bio(struct drbd_conf *mdev,
+		struct bio *bio, int complete, struct drbd_request *r)
+{
+	MTRACE(TraceTypeRq, TraceLvlSummary,
+	       _dump_bio("Rq", mdev, bio, complete, r);
+		);
+}
+
+static inline void dump_internal_bio(const char *pfx, struct drbd_conf *mdev, struct bio *bio, int complete)
+{
+	MTRACE(TraceTypeIntRq, TraceLvlSummary,
+	       _dump_bio(pfx, mdev, bio, complete, NULL);
+		);
+}
+
+/* Packet dumping support */
+extern void _dump_packet(struct drbd_conf *mdev, struct socket *sock,
+			 int recv, union Drbd_Polymorph_Packet *p,
+			 char *file, int line);
+
+static inline void
+dump_packet(struct drbd_conf *mdev, struct socket *sock,
+	    int recv, union Drbd_Polymorph_Packet *p, char *file, int line)
+{
+	MTRACE(TraceTypePacket, TraceLvlSummary,
+	       _dump_packet(mdev, sock, recv, p, file, line);
+		);
+}
+
+#else
+
+#define MTRACE(ignored...) ((void)0)
+#define TRACE(ignored...) ((void)0)
+
+#define dump_bio(ignored...) ((void)0)
+#define dump_internal_bio(ignored...) ((void)0)
+#define dump_packet(ignored...) ((void)0)
+#endif
+
+/* drbd_req */
+extern int drbd_make_request_26(struct request_queue *q, struct bio *bio);
+extern int drbd_read_remote(struct drbd_conf *mdev, struct drbd_request *req);
+extern int drbd_merge_bvec(struct request_queue *q, struct bvec_merge_data *bvm, struct bio_vec *bvec);
+extern int is_valid_ar_handle(struct drbd_request *, sector_t);
+
+
+/* drbd_nl.c */
+extern void drbd_suspend_io(struct drbd_conf *mdev);
+extern void drbd_resume_io(struct drbd_conf *mdev);
+extern char *ppsize(char *buf, unsigned long long size);
+extern sector_t drbd_new_dev_size(struct drbd_conf *,
+		struct drbd_backing_dev *);
+enum determin_dev_size_enum { dev_size_error = -1, unchanged = 0, shrunk = 1, grew = 2 };
+extern enum determin_dev_size_enum drbd_determin_dev_size(struct drbd_conf *) __must_hold(local);
+extern void resync_after_online_grow(struct drbd_conf *);
+extern void drbd_setup_queue_param(struct drbd_conf *mdev, unsigned int) __must_hold(local);
+extern int drbd_set_role(struct drbd_conf *mdev, enum drbd_role new_role,
+		int force);
+enum drbd_disk_state drbd_try_outdate_peer(struct drbd_conf *mdev);
+extern int drbd_khelper(struct drbd_conf *mdev, char *cmd);
+
+/* drbd_worker.c */
+extern int drbd_worker(struct Drbd_thread *thi);
+extern void drbd_alter_sa(struct drbd_conf *mdev, int na);
+extern void drbd_start_resync(struct drbd_conf *mdev, enum drbd_conns side);
+extern void resume_next_sg(struct drbd_conf *mdev);
+extern void suspend_other_sg(struct drbd_conf *mdev);
+extern int drbd_resync_finished(struct drbd_conf *mdev);
+/* maybe rather drbd_main.c ? */
+extern int drbd_md_sync_page_io(struct drbd_conf *mdev,
+		struct drbd_backing_dev *bdev, sector_t sector, int rw);
+extern void drbd_ov_oos_found(struct drbd_conf*, sector_t, int);
+
+static inline void ov_oos_print(struct drbd_conf *mdev)
+{
+	if (mdev->ov_last_oos_size) {
+		ERR("Out of sync: start=%llu, size=%lu (sectors)\n",
+		     (unsigned long long)mdev->ov_last_oos_start,
+		     (unsigned long)mdev->ov_last_oos_size);
+	}
+	mdev->ov_last_oos_size=0;
+}
+
+
+void drbd_csum(struct drbd_conf *, struct crypto_hash *, struct bio *, void *);
+/* worker callbacks */
+extern int w_req_cancel_conflict(struct drbd_conf *, struct drbd_work *, int);
+extern int w_read_retry_remote(struct drbd_conf *, struct drbd_work *, int);
+extern int w_e_end_data_req(struct drbd_conf *, struct drbd_work *, int);
+extern int w_e_end_rsdata_req(struct drbd_conf *, struct drbd_work *, int);
+extern int w_e_end_csum_rs_req(struct drbd_conf *, struct drbd_work *, int);
+extern int w_e_end_ov_reply(struct drbd_conf *, struct drbd_work *, int);
+extern int w_e_end_ov_req(struct drbd_conf *, struct drbd_work *, int);
+extern int w_ov_finished(struct drbd_conf *, struct drbd_work *, int);
+extern int w_resync_inactive(struct drbd_conf *, struct drbd_work *, int);
+extern int w_resume_next_sg(struct drbd_conf *, struct drbd_work *, int);
+extern int w_io_error(struct drbd_conf *, struct drbd_work *, int);
+extern int w_send_write_hint(struct drbd_conf *, struct drbd_work *, int);
+extern int w_make_resync_request(struct drbd_conf *, struct drbd_work *, int);
+extern int w_send_dblock(struct drbd_conf *, struct drbd_work *, int);
+extern int w_send_barrier(struct drbd_conf *, struct drbd_work *, int);
+extern int w_send_read_req(struct drbd_conf *, struct drbd_work *, int);
+extern int w_prev_work_done(struct drbd_conf *, struct drbd_work *, int);
+extern int w_e_reissue(struct drbd_conf *, struct drbd_work *, int);
+
+extern void resync_timer_fn(unsigned long data);
+
+/* drbd_receiver.c */
+extern int drbd_release_ee(struct drbd_conf *mdev, struct list_head *list);
+extern struct Tl_epoch_entry *drbd_alloc_ee(struct drbd_conf *mdev,
+					    u64 id,
+					    sector_t sector,
+					    unsigned int data_size,
+					    gfp_t gfp_mask) __must_hold(local);
+extern void drbd_free_ee(struct drbd_conf *mdev, struct Tl_epoch_entry *e);
+extern void drbd_wait_ee_list_empty(struct drbd_conf *mdev,
+		struct list_head *head);
+extern void _drbd_wait_ee_list_empty(struct drbd_conf *mdev,
+		struct list_head *head);
+extern void drbd_set_recv_tcq(struct drbd_conf *mdev, int tcq_enabled);
+extern void _drbd_clear_done_ee(struct drbd_conf *mdev);
+
+/* yes, there is kernel_setsockopt, but only since 2.6.18. we don't need to
+ * mess with get_fs/set_fs, we know we are KERNEL_DS always. */
+static inline int drbd_setsockopt(struct socket *sock, int level, int optname,
+			char __user *optval, int optlen)
+{
+	int err;
+	if (level == SOL_SOCKET)
+		err = sock_setsockopt(sock, level, optname, optval, optlen);
+	else
+		err = sock->ops->setsockopt(sock, level, optname, optval,
+					    optlen);
+	return err;
+}
+
+static inline void drbd_tcp_cork(struct socket *sock)
+{
+	int __user val = 1;
+	(void) drbd_setsockopt(sock, SOL_TCP, TCP_CORK,
+			(char __user *)&val, sizeof(val));
+}
+
+static inline void drbd_tcp_uncork(struct socket *sock)
+{
+	int __user val = 0;
+	(void) drbd_setsockopt(sock, SOL_TCP, TCP_CORK,
+			(char __user *)&val, sizeof(val));
+}
+
+static inline void drbd_tcp_nodelay(struct socket *sock)
+{
+	int __user val = 1;
+	(void) drbd_setsockopt(sock, SOL_TCP, TCP_NODELAY,
+			(char __user *)&val, sizeof(val));
+}
+
+static inline void drbd_tcp_quickack(struct socket *sock)
+{
+	int __user val = 1;
+	(void) drbd_setsockopt(sock, SOL_TCP, TCP_QUICKACK,
+			(char __user *)&val, sizeof(val));
+}
+
+void drbd_bump_write_ordering(struct drbd_conf *mdev, enum write_ordering_e wo);
+
+/* drbd_proc.c */
+extern struct proc_dir_entry *drbd_proc;
+extern struct file_operations drbd_proc_fops;
+extern const char *conns_to_name(enum drbd_conns s);
+extern const char *roles_to_name(enum drbd_role s);
+
+/* drbd_actlog.c */
+extern void drbd_al_begin_io(struct drbd_conf *mdev, sector_t sector);
+extern void drbd_al_complete_io(struct drbd_conf *mdev, sector_t sector);
+extern void drbd_rs_complete_io(struct drbd_conf *mdev, sector_t sector);
+extern int drbd_rs_begin_io(struct drbd_conf *mdev, sector_t sector);
+extern int drbd_try_rs_begin_io(struct drbd_conf *mdev, sector_t sector);
+extern void drbd_rs_cancel_all(struct drbd_conf *mdev);
+extern int drbd_rs_del_all(struct drbd_conf *mdev);
+extern void drbd_rs_failed_io(struct drbd_conf *mdev,
+		sector_t sector, int size);
+extern int drbd_al_read_log(struct drbd_conf *mdev, struct drbd_backing_dev *);
+extern void __drbd_set_in_sync(struct drbd_conf *mdev, sector_t sector,
+		int size, const char *file, const unsigned int line);
+#define drbd_set_in_sync(mdev, sector, size) \
+	__drbd_set_in_sync(mdev, sector, size, __FILE__, __LINE__)
+extern void __drbd_set_out_of_sync(struct drbd_conf *mdev, sector_t sector,
+		int size, const char *file, const unsigned int line);
+#define drbd_set_out_of_sync(mdev, sector, size) \
+	__drbd_set_out_of_sync(mdev, sector, size, __FILE__, __LINE__)
+extern void drbd_al_apply_to_bm(struct drbd_conf *mdev);
+extern void drbd_al_to_on_disk_bm(struct drbd_conf *mdev);
+extern void drbd_al_shrink(struct drbd_conf *mdev);
+
+
+/* drbd_nl.c */
+
+void drbd_nl_cleanup(void);
+int __init drbd_nl_init(void);
+void drbd_bcast_state(struct drbd_conf *mdev, union drbd_state_t);
+void drbd_bcast_sync_progress(struct drbd_conf *mdev);
+void drbd_bcast_ee(struct drbd_conf *mdev,
+		const char *reason, const int dgs,
+		const char* seen_hash, const char* calc_hash,
+		const struct Tl_epoch_entry* e);
+
+
+/** DRBD State macros:
+ * These macros are used to express state changes in easily readable form.
+ *
+ * The NS macros expand to a mask and a value, that can be bit ored onto the
+ * current state as soon as the spinlock (req_lock) was taken.
+ *
+ * The _NS macros are used for state functions that get called with the
+ * spinlock. These macros expand directly to the new state value.
+ *
+ * Besides the basic forms NS() and _NS() additional _?NS[23] are defined
+ * to express state changes that affect more than one aspect of the state.
+ *
+ * E.g. NS2(conn, Connected, peer, Secondary)
+ * Means that the network connection was established and that the peer
+ * is in secondary role.
+ */
+#define peer_mask role_mask
+#define pdsk_mask disk_mask
+#define susp_mask 1
+#define user_isp_mask 1
+#define aftr_isp_mask 1
+
+#define NS(T, S) \
+	({ union drbd_state_t mask; mask.i = 0; mask.T = T##_mask; mask; }), \
+	({ union drbd_state_t val; val.i = 0; val.T = (S); val; })
+#define NS2(T1, S1, T2, S2) \
+	({ union drbd_state_t mask; mask.i = 0; mask.T1 = T1##_mask; \
+	  mask.T2 = T2##_mask; mask; }), \
+	({ union drbd_state_t val; val.i = 0; val.T1 = (S1); \
+	  val.T2 = (S2); val; })
+#define NS3(T1, S1, T2, S2, T3, S3) \
+	({ union drbd_state_t mask; mask.i = 0; mask.T1 = T1##_mask; \
+	  mask.T2 = T2##_mask; mask.T3 = T3##_mask; mask; }), \
+	({ union drbd_state_t val;  val.i = 0; val.T1 = (S1); \
+	  val.T2 = (S2); val.T3 = (S3); val; })
+
+#define _NS(D, T, S) \
+	D, ({ union drbd_state_t __ns; __ns.i = D->state.i; __ns.T = (S); __ns; })
+#define _NS2(D, T1, S1, T2, S2) \
+	D, ({ union drbd_state_t __ns; __ns.i = D->state.i; __ns.T1 = (S1); \
+	__ns.T2 = (S2); __ns; })
+#define _NS3(D, T1, S1, T2, S2, T3, S3) \
+	D, ({ union drbd_state_t __ns; __ns.i = D->state.i; __ns.T1 = (S1); \
+	__ns.T2 = (S2); __ns.T3 = (S3); __ns; })
+
+/*
+ * inline helper functions
+ *************************/
+
+static inline void drbd_state_lock(struct drbd_conf *mdev)
+{
+	wait_event(mdev->misc_wait,
+		   !test_and_set_bit(CLUSTER_ST_CHANGE, &mdev->flags));
+}
+
+static inline void drbd_state_unlock(struct drbd_conf *mdev)
+{
+	clear_bit(CLUSTER_ST_CHANGE, &mdev->flags);
+	wake_up(&mdev->misc_wait);
+}
+
+static inline int _drbd_set_state(struct drbd_conf *mdev,
+				   union drbd_state_t ns, enum chg_state_flags flags,
+				   struct completion *done)
+{
+	int rv;
+
+	read_lock(&global_state_lock);
+	rv = __drbd_set_state(mdev, ns, flags, done);
+	read_unlock(&global_state_lock);
+
+	return rv;
+}
+
+static inline int drbd_request_state(struct drbd_conf *mdev,
+				     union drbd_state_t mask,
+				     union drbd_state_t val)
+{
+	return _drbd_request_state(mdev, mask, val, ChgStateVerbose + ChgOrdered);
+}
+
+/**
+ * drbd_chk_io_error: Handles the on_io_error setting, should be called from
+ * all io completion handlers. See also drbd_io_error().
+ */
+static inline void __drbd_chk_io_error(struct drbd_conf *mdev, int forcedetach)
+{
+	switch (mdev->bc->dc.on_io_error) {
+	case PassOn:
+		if (!forcedetach) {
+			if (printk_ratelimit())
+				ERR("Local IO failed. Passing error on...\n");
+			break;
+		}
+		/* NOTE fall through to detach case if forcedetach set */
+	case Detach:
+	case CallIOEHelper:
+		if (mdev->state.disk > Failed) {
+			_drbd_set_state(_NS(mdev, disk, Failed), ChgStateHard, NULL);
+			ERR("Local IO failed. Detaching...\n");
+		}
+		break;
+	}
+}
+
+static inline void drbd_chk_io_error(struct drbd_conf *mdev,
+	int error, int forcedetach)
+{
+	if (error) {
+		unsigned long flags;
+		spin_lock_irqsave(&mdev->req_lock, flags);
+		__drbd_chk_io_error(mdev, forcedetach);
+		spin_unlock_irqrestore(&mdev->req_lock, flags);
+	}
+}
+
+/* Returns the first sector number of our meta data,
+ * which, for internal meta data, happens to be the maximum capacity
+ * we could agree upon with our peer
+ */
+static inline sector_t drbd_md_first_sector(struct drbd_backing_dev *bdev)
+{
+	switch (bdev->dc.meta_dev_idx) {
+	case DRBD_MD_INDEX_INTERNAL:
+	case DRBD_MD_INDEX_FLEX_INT:
+		return bdev->md.md_offset + bdev->md.bm_offset;
+	case DRBD_MD_INDEX_FLEX_EXT:
+	default:
+		return bdev->md.md_offset;
+	}
+}
+
+/* returns the last sector number of our meta data,
+ * to be able to catch out of band md access */
+static inline sector_t drbd_md_last_sector(struct drbd_backing_dev *bdev)
+{
+	switch (bdev->dc.meta_dev_idx) {
+	case DRBD_MD_INDEX_INTERNAL:
+	case DRBD_MD_INDEX_FLEX_INT:
+		return bdev->md.md_offset + MD_AL_OFFSET - 1;
+	case DRBD_MD_INDEX_FLEX_EXT:
+	default:
+		return bdev->md.md_offset + bdev->md.md_size_sect;
+	}
+}
+
+/* Returns the number of 512 byte sectors of the device */
+static inline sector_t drbd_get_capacity(struct block_device *bdev)
+{
+	/* return bdev ? get_capacity(bdev->bd_disk) : 0; */
+	return bdev ? bdev->bd_inode->i_size >> 9 : 0;
+}
+
+/* returns the capacity we announce to out peer.
+ * we clip ourselves at the various MAX_SECTORS, because if we don't,
+ * current implementation will oops sooner or later */
+static inline sector_t drbd_get_max_capacity(struct drbd_backing_dev *bdev)
+{
+	sector_t s;
+	switch (bdev->dc.meta_dev_idx) {
+	case DRBD_MD_INDEX_INTERNAL:
+	case DRBD_MD_INDEX_FLEX_INT:
+		s = drbd_get_capacity(bdev->backing_bdev)
+			? min_t(sector_t, DRBD_MAX_SECTORS_FLEX,
+					drbd_md_first_sector(bdev))
+			: 0;
+		break;
+	case DRBD_MD_INDEX_FLEX_EXT:
+		s = min_t(sector_t, DRBD_MAX_SECTORS_FLEX,
+				drbd_get_capacity(bdev->backing_bdev));
+		/* clip at maximum size the meta device can support */
+		s = min_t(sector_t, s,
+			BM_EXT_TO_SECT(bdev->md.md_size_sect
+				     - bdev->md.bm_offset));
+		break;
+	default:
+		s = min_t(sector_t, DRBD_MAX_SECTORS,
+				drbd_get_capacity(bdev->backing_bdev));
+	}
+	return s;
+}
+
+/* returns the sector number of our meta data 'super' block */
+static inline sector_t drbd_md_ss__(struct drbd_conf *mdev,
+				    struct drbd_backing_dev *bdev)
+{
+	switch (bdev->dc.meta_dev_idx) {
+	default: /* external, some index */
+		return MD_RESERVED_SECT * bdev->dc.meta_dev_idx;
+	case DRBD_MD_INDEX_INTERNAL:
+		/* with drbd08, internal meta data is always "flexible" */
+	case DRBD_MD_INDEX_FLEX_INT:
+		/* sizeof(struct md_on_disk_07) == 4k
+		 * position: last 4k aligned block of 4k size */
+		if (!bdev->backing_bdev) {
+			if (__ratelimit(&drbd_ratelimit_state)) {
+				ERR("bdev->backing_bdev==NULL\n");
+				dump_stack();
+			}
+			return 0;
+		}
+		return (drbd_get_capacity(bdev->backing_bdev) & ~7ULL)
+			- MD_AL_OFFSET;
+	case DRBD_MD_INDEX_FLEX_EXT:
+		return 0;
+	}
+}
+
+static inline void
+_drbd_queue_work(struct drbd_work_queue *q, struct drbd_work *w)
+{
+	list_add_tail(&w->list, &q->q);
+	up(&q->s);
+}
+
+static inline void
+drbd_queue_work_front(struct drbd_work_queue *q, struct drbd_work *w)
+{
+	unsigned long flags;
+	spin_lock_irqsave(&q->q_lock, flags);
+	list_add(&w->list, &q->q);
+	up(&q->s); /* within the spinlock,
+		      see comment near end of drbd_worker() */
+	spin_unlock_irqrestore(&q->q_lock, flags);
+}
+
+static inline void
+drbd_queue_work(struct drbd_work_queue *q, struct drbd_work *w)
+{
+	unsigned long flags;
+	spin_lock_irqsave(&q->q_lock, flags);
+	list_add_tail(&w->list, &q->q);
+	up(&q->s); /* within the spinlock,
+		      see comment near end of drbd_worker() */
+	spin_unlock_irqrestore(&q->q_lock, flags);
+}
+
+static inline void wake_asender(struct drbd_conf *mdev)
+{
+	if (test_bit(SIGNAL_ASENDER, &mdev->flags))
+		force_sig(DRBD_SIG, mdev->asender.task);
+}
+
+static inline void request_ping(struct drbd_conf *mdev)
+{
+	set_bit(SEND_PING, &mdev->flags);
+	wake_asender(mdev);
+}
+
+static inline int drbd_send_short_cmd(struct drbd_conf *mdev,
+	enum Drbd_Packet_Cmd cmd)
+{
+	struct Drbd_Header h;
+	return drbd_send_cmd(mdev, USE_DATA_SOCKET, cmd, &h, sizeof(h));
+}
+
+static inline int drbd_send_ping(struct drbd_conf *mdev)
+{
+	struct Drbd_Header h;
+	return drbd_send_cmd(mdev, USE_META_SOCKET, Ping, &h, sizeof(h));
+}
+
+static inline int drbd_send_ping_ack(struct drbd_conf *mdev)
+{
+	struct Drbd_Header h;
+	return drbd_send_cmd(mdev, USE_META_SOCKET, PingAck, &h, sizeof(h));
+}
+
+static inline void drbd_thread_stop(struct Drbd_thread *thi)
+{
+	_drbd_thread_stop(thi, FALSE, TRUE);
+}
+
+static inline void drbd_thread_stop_nowait(struct Drbd_thread *thi)
+{
+	_drbd_thread_stop(thi, FALSE, FALSE);
+}
+
+static inline void drbd_thread_restart_nowait(struct Drbd_thread *thi)
+{
+	_drbd_thread_stop(thi, TRUE, FALSE);
+}
+
+/* counts how many answer packets packets we expect from our peer,
+ * for either explicit application requests,
+ * or implicit barrier packets as necessary.
+ * increased:
+ *  w_send_barrier
+ *  _req_mod(req, queue_for_net_write or queue_for_net_read);
+ *    it is much easier and equally valid to count what we queue for the
+ *    worker, even before it actually was queued or send.
+ *    (drbd_make_request_common; recovery path on read io-error)
+ * decreased:
+ *  got_BarrierAck (respective tl_clear, tl_clear_barrier)
+ *  _req_mod(req, data_received)
+ *     [from receive_DataReply]
+ *  _req_mod(req, write_acked_by_peer or recv_acked_by_peer or neg_acked)
+ *     [from got_BlockAck (WriteAck, RecvAck)]
+ *     for some reason it is NOT decreased in got_NegAck,
+ *     but in the resulting cleanup code from report_params.
+ *     we should try to remember the reason for that...
+ *  _req_mod(req, send_failed or send_canceled)
+ *  _req_mod(req, connection_lost_while_pending)
+ *     [from tl_clear_barrier]
+ */
+static inline void inc_ap_pending(struct drbd_conf *mdev)
+{
+	atomic_inc(&mdev->ap_pending_cnt);
+}
+
+#define ERR_IF_CNT_IS_NEGATIVE(which)				\
+	if (atomic_read(&mdev->which) < 0)			\
+		ERR("in %s:%d: " #which " = %d < 0 !\n",	\
+		    __func__ , __LINE__ ,			\
+		    atomic_read(&mdev->which))
+
+#define dec_ap_pending(mdev)	do {				\
+	typecheck(struct drbd_conf *, mdev);			\
+	if (atomic_dec_and_test(&mdev->ap_pending_cnt))		\
+		wake_up(&mdev->misc_wait);			\
+	ERR_IF_CNT_IS_NEGATIVE(ap_pending_cnt); } while (0)
+
+/* counts how many resync-related answers we still expect from the peer
+ *		     increase			decrease
+ * SyncTarget sends RSDataRequest (and expects RSDataReply)
+ * SyncSource sends RSDataReply   (and expects WriteAck whith ID_SYNCER)
+ *					   (or NegAck with ID_SYNCER)
+ */
+static inline void inc_rs_pending(struct drbd_conf *mdev)
+{
+	atomic_inc(&mdev->rs_pending_cnt);
+}
+
+#define dec_rs_pending(mdev)	do {				\
+	typecheck(struct drbd_conf *, mdev);			\
+	atomic_dec(&mdev->rs_pending_cnt);			\
+	ERR_IF_CNT_IS_NEGATIVE(rs_pending_cnt); } while (0)
+
+/* counts how many answers we still need to send to the peer.
+ * increased on
+ *  receive_Data	unless protocol A;
+ *			we need to send a RecvAck (proto B)
+ *			or WriteAck (proto C)
+ *  receive_RSDataReply (recv_resync_read) we need to send a WriteAck
+ *  receive_DataRequest (receive_RSDataRequest) we need to send back Data
+ *  receive_Barrier_*	we need to send a BarrierAck
+ */
+static inline void inc_unacked(struct drbd_conf *mdev)
+{
+	atomic_inc(&mdev->unacked_cnt);
+}
+
+#define dec_unacked(mdev)	do {				\
+	typecheck(struct drbd_conf *, mdev);			\
+	atomic_dec(&mdev->unacked_cnt);				\
+	ERR_IF_CNT_IS_NEGATIVE(unacked_cnt); } while (0)
+
+#define sub_unacked(mdev, n)	do {				\
+	typecheck(struct drbd_conf *, mdev);			\
+	atomic_sub(n, &mdev->unacked_cnt);			\
+	ERR_IF_CNT_IS_NEGATIVE(unacked_cnt); } while (0)
+
+
+static inline void dec_net(struct drbd_conf *mdev)
+{
+	if (atomic_dec_and_test(&mdev->net_cnt))
+		wake_up(&mdev->misc_wait);
+}
+
+/**
+ * inc_net: Returns TRUE when it is ok to access mdev->net_conf. You
+ * should call dec_net() when finished looking at mdev->net_conf.
+ */
+static inline int inc_net(struct drbd_conf *mdev)
+{
+	int have_net_conf;
+
+	atomic_inc(&mdev->net_cnt);
+	have_net_conf = mdev->state.conn >= Unconnected;
+	if (!have_net_conf)
+		dec_net(mdev);
+	return have_net_conf;
+}
+
+/**
+ * inc_local: Returns TRUE when local IO is possible. If it returns
+ * TRUE you should call dec_local() after IO is completed.
+ */
+#define inc_local_if_state(M,MINS) __cond_lock(local, _inc_local_if_state(M,MINS))
+#define inc_local(M) __cond_lock(local, _inc_local_if_state(M,Inconsistent))
+
+static inline void dec_local(struct drbd_conf *mdev)
+{
+	__release(local);
+	if (atomic_dec_and_test(&mdev->local_cnt))
+		wake_up(&mdev->misc_wait);
+	D_ASSERT(atomic_read(&mdev->local_cnt) >= 0);
+}
+
+#ifndef __CHECKER__
+static inline int _inc_local_if_state(struct drbd_conf *mdev, enum drbd_disk_state mins)
+{
+	int io_allowed;
+
+	atomic_inc(&mdev->local_cnt);
+	io_allowed = (mdev->state.disk >= mins);
+	if (!io_allowed)
+		dec_local(mdev);
+	return io_allowed;
+}
+#else
+extern int _inc_local_if_state(struct drbd_conf *mdev, enum drbd_disk_state mins);
+#endif
+
+/* you must have an "inc_local" reference */
+static inline void drbd_get_syncer_progress(struct drbd_conf *mdev,
+		unsigned long *bits_left, unsigned int *per_mil_done)
+{
+	/*
+	 * this is to break it at compile time when we change that
+	 * (we may feel 4TB maximum storage per drbd is not enough)
+	 */
+	typecheck(unsigned long, mdev->rs_total);
+
+	/* note: both rs_total and rs_left are in bits, i.e. in
+	 * units of BM_BLOCK_SIZE.
+	 * for the percentage, we don't care. */
+
+	*bits_left = drbd_bm_total_weight(mdev) - mdev->rs_failed;
+	/* >> 10 to prevent overflow,
+	 * +1 to prevent division by zero */
+	if (*bits_left > mdev->rs_total) {
+		/* doh. maybe a logic bug somewhere.
+		 * may also be just a race condition
+		 * between this and a disconnect during sync.
+		 * for now, just prevent in-kernel buffer overflow.
+		 */
+		smp_rmb();
+		drbd_WARN("cs:%s rs_left=%lu > rs_total=%lu (rs_failed %lu)\n",
+				conns_to_name(mdev->state.conn),
+				*bits_left, mdev->rs_total, mdev->rs_failed);
+		*per_mil_done = 0;
+	} else {
+		/* make sure the calculation happens in long context */
+		unsigned long tmp = 1000UL -
+				(*bits_left >> 10)*1000UL
+				/ ((mdev->rs_total >> 10) + 1UL);
+		*per_mil_done = tmp;
+	}
+}
+
+
+/* this throttles on-the-fly application requests
+ * according to max_buffers settings;
+ * maybe re-implement using semaphores? */
+static inline int drbd_get_max_buffers(struct drbd_conf *mdev)
+{
+	int mxb = 1000000; /* arbitrary limit on open requests */
+	if (inc_net(mdev)) {
+		mxb = mdev->net_conf->max_buffers;
+		dec_net(mdev);
+	}
+	return mxb;
+}
+
+static inline int drbd_state_is_stable(union drbd_state_t s)
+{
+
+	/* DO NOT add a default clause, we want the compiler to warn us
+	 * for any newly introduced state we may have forgotten to add here */
+
+	switch ((enum drbd_conns)s.conn) {
+	/* new io only accepted when there is no connection, ... */
+	case StandAlone:
+	case WFConnection:
+	/* ... or there is a well established connection. */
+	case Connected:
+	case SyncSource:
+	case SyncTarget:
+	case VerifyS:
+	case VerifyT:
+	case PausedSyncS:
+	case PausedSyncT:
+		/* maybe stable, look at the disk state */
+		break;
+
+	/* no new io accepted during tansitional states
+	 * like handshake or teardown */
+	case Disconnecting:
+	case Unconnected:
+	case Timeout:
+	case BrokenPipe:
+	case NetworkFailure:
+	case ProtocolError:
+	case TearDown:
+	case WFReportParams:
+	case StartingSyncS:
+	case StartingSyncT:
+	case WFBitMapS:
+	case WFBitMapT:
+	case WFSyncUUID:
+	case conn_mask:
+		/* not "stable" */
+		return 0;
+	}
+
+	switch ((enum drbd_disk_state)s.disk) {
+	case Diskless:
+	case Inconsistent:
+	case Outdated:
+	case Consistent:
+	case UpToDate:
+		/* disk state is stable as well. */
+		break;
+
+	/* no new io accepted during tansitional states */
+	case Attaching:
+	case Failed:
+	case Negotiating:
+	case DUnknown:
+	case disk_mask:
+		/* not "stable" */
+		return 0;
+	}
+
+	return 1;
+}
+
+static inline int __inc_ap_bio_cond(struct drbd_conf *mdev)
+{
+	int mxb = drbd_get_max_buffers(mdev);
+
+	if (mdev->state.susp)
+		return 0;
+	if (test_bit(SUSPEND_IO, &mdev->flags))
+		return 0;
+
+	/* to avoid potential deadlock or bitmap corruption,
+	 * in various places, we only allow new application io
+	 * to start during "stable" states. */
+
+	/* no new io accepted when attaching or detaching the disk */
+	if (!drbd_state_is_stable(mdev->state))
+		return 0;
+
+	/* since some older kernels don't have atomic_add_unless,
+	 * and we are within the spinlock anyways, we have this workaround.  */
+	if (atomic_read(&mdev->ap_bio_cnt) > mxb)
+		return 0;
+	if (test_bit(BITMAP_IO, &mdev->flags))
+		return 0;
+	return 1;
+}
+
+/* I'd like to use wait_event_lock_irq,
+ * but I'm not sure when it got introduced,
+ * and not sure when it has 3 or 4 arguments */
+static inline void inc_ap_bio(struct drbd_conf *mdev, int one_or_two)
+{
+	/* compare with after_state_ch,
+	 * os.conn != WFBitMapS && ns.conn == WFBitMapS */
+	DEFINE_WAIT(wait);
+
+	/* we wait here
+	 *    as long as the device is suspended
+	 *    until the bitmap is no longer on the fly during connection
+	 *    handshake as long as we would exeed the max_buffer limit.
+	 *
+	 * to avoid races with the reconnect code,
+	 * we need to atomic_inc within the spinlock. */
+
+	spin_lock_irq(&mdev->req_lock);
+	while (!__inc_ap_bio_cond(mdev)) {
+		prepare_to_wait(&mdev->misc_wait, &wait, TASK_UNINTERRUPTIBLE);
+		spin_unlock_irq(&mdev->req_lock);
+		schedule();
+		finish_wait(&mdev->misc_wait, &wait);
+		spin_lock_irq(&mdev->req_lock);
+	}
+	atomic_add(one_or_two, &mdev->ap_bio_cnt);
+	spin_unlock_irq(&mdev->req_lock);
+}
+
+static inline void dec_ap_bio(struct drbd_conf *mdev)
+{
+	int mxb = drbd_get_max_buffers(mdev);
+	int ap_bio = atomic_dec_return(&mdev->ap_bio_cnt);
+
+	D_ASSERT(ap_bio >= 0);
+	/* this currently does wake_up for every dec_ap_bio!
+	 * maybe rather introduce some type of hysteresis?
+	 * e.g. (ap_bio == mxb/2 || ap_bio == 0) ? */
+	if (ap_bio < mxb)
+		wake_up(&mdev->misc_wait);
+	if (ap_bio == 0 && test_bit(BITMAP_IO, &mdev->flags)) {
+		if (!test_and_set_bit(BITMAP_IO_QUEUED, &mdev->flags))
+			drbd_queue_work(&mdev->data.work, &mdev->bm_io_work.w);
+	}
+}
+
+static inline void drbd_set_ed_uuid(struct drbd_conf *mdev, u64 val)
+{
+	mdev->ed_uuid = val;
+
+	MTRACE(TraceTypeUuid, TraceLvlMetrics,
+	       INFO(" exposed data uuid now %016llX\n",
+		    (unsigned long long)val);
+		);
+}
+
+static inline int seq_cmp(u32 a, u32 b)
+{
+	/* we assume wrap around at 32bit.
+	 * for wrap around at 24bit (old atomic_t),
+	 * we'd have to
+	 *  a <<= 8; b <<= 8;
+	 */
+	return (s32)(a) - (s32)(b);
+}
+#define seq_lt(a, b) (seq_cmp((a), (b)) < 0)
+#define seq_gt(a, b) (seq_cmp((a), (b)) > 0)
+#define seq_ge(a, b) (seq_cmp((a), (b)) >= 0)
+#define seq_le(a, b) (seq_cmp((a), (b)) <= 0)
+/* CAUTION: please no side effects in arguments! */
+#define seq_max(a, b) ((u32)(seq_gt((a), (b)) ? (a) : (b)))
+
+static inline void update_peer_seq(struct drbd_conf *mdev, unsigned int new_seq)
+{
+	unsigned int m;
+	spin_lock(&mdev->peer_seq_lock);
+	m = seq_max(mdev->peer_seq, new_seq);
+	mdev->peer_seq = m;
+	spin_unlock(&mdev->peer_seq_lock);
+	if (m == new_seq)
+		wake_up(&mdev->seq_wait);
+}
+
+static inline void drbd_update_congested(struct drbd_conf *mdev)
+{
+	struct sock *sk = mdev->data.socket->sk;
+	if (sk->sk_wmem_queued > sk->sk_sndbuf * 4 / 5)
+		set_bit(NET_CONGESTED, &mdev->flags);
+}
+
+static inline int drbd_queue_order_type(struct drbd_conf *mdev)
+{
+	/* sorry, we currently have no working implementation
+	 * of distributed TCQ stuff */
+#ifndef QUEUE_ORDERED_NONE
+#define QUEUE_ORDERED_NONE 0
+#endif
+	return QUEUE_ORDERED_NONE;
+}
+
+static inline void drbd_blk_run_queue(struct request_queue *q)
+{
+	if (q && q->unplug_fn)
+		q->unplug_fn(q);
+}
+
+static inline void drbd_kick_lo(struct drbd_conf *mdev)
+{
+	if (inc_local(mdev)) {
+		drbd_blk_run_queue(bdev_get_queue(mdev->bc->backing_bdev));
+		dec_local(mdev);
+	}
+}
+
+static inline void drbd_md_flush(struct drbd_conf *mdev)
+{
+	int r;
+
+	if (test_bit(MD_NO_BARRIER, &mdev->flags))
+		return;
+
+	r = blkdev_issue_flush(mdev->bc->md_bdev, NULL);
+	if (r) {
+		set_bit(MD_NO_BARRIER, &mdev->flags);
+		ERR("meta data flush failed with status %d, disabling md-flushes\n", r);
+	}
+}
+
+#endif
diff -uNrp linux-2.6.29/drivers/block/drbd/drbd_wrappers.h linux-2.6.29-drbd/drivers/block/drbd/drbd_wrappers.h
--- linux-2.6.29/drivers/block/drbd/drbd_wrappers.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.29-drbd/drivers/block/drbd/drbd_wrappers.h	2009-03-26 15:55:39.587133000 +0100
@@ -0,0 +1,117 @@
+#include <linux/ctype.h>
+#include <linux/mm.h>
+
+
+/* see get_sb_bdev and bd_claim */
+extern char *drbd_sec_holder;
+
+static inline sector_t drbd_get_hardsect(struct block_device *bdev)
+{
+	return bdev->bd_disk->queue->hardsect_size;
+}
+
+/* sets the number of 512 byte sectors of our virtual device */
+static inline void drbd_set_my_capacity(struct drbd_conf *mdev,
+					sector_t size)
+{
+	/* set_capacity(mdev->this_bdev->bd_disk, size); */
+	set_capacity(mdev->vdisk, size);
+	mdev->this_bdev->bd_inode->i_size = (loff_t)size << 9;
+}
+
+#define drbd_bio_uptodate(bio) bio_flagged(bio, BIO_UPTODATE)
+
+static inline int drbd_bio_has_active_page(struct bio *bio)
+{
+	struct bio_vec *bvec;
+	int i;
+
+	__bio_for_each_segment(bvec, bio, i, 0) {
+		if (page_count(bvec->bv_page) > 1)
+			return 1;
+	}
+
+	return 0;
+}
+
+/* bi_end_io handlers */
+extern void drbd_md_io_complete(struct bio *bio, int error);
+extern void drbd_endio_read_sec(struct bio *bio, int error);
+extern void drbd_endio_write_sec(struct bio *bio, int error);
+extern void drbd_endio_pri(struct bio *bio, int error);
+
+/* how to get to the kobj of a gendisk.
+ * see also upstream commits
+ * edfaa7c36574f1bf09c65ad602412db9da5f96bf
+ * ed9e1982347b36573cd622ee5f4e2a7ccd79b3fd
+ * 548b10eb2959c96cef6fc29fc96e0931eeb53bc5
+ */
+#ifndef dev_to_disk
+# define disk_to_kobj(disk) (&(disk)->kobj)
+#else
+# ifndef disk_to_dev
+#  define disk_to_dev(disk) (&(disk)->dev)
+# endif
+# define disk_to_kobj(disk) (&disk_to_dev(disk)->kobj)
+#endif
+static inline void drbd_kobject_uevent(struct drbd_conf *mdev)
+{
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,10)
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,15)
+	kobject_uevent(disk_to_kobj(mdev->vdisk), KOBJ_CHANGE, NULL);
+#else
+	kobject_uevent(disk_to_kobj(mdev->vdisk), KOBJ_CHANGE);
+	/* rhel4 / sles9 and older don't have this at all,
+	 * which means user space (udev) won't get events about possible changes of
+	 * corresponding resource + disk names after the initial drbd minor creation.
+	 */
+#endif
+#endif
+}
+
+
+/*
+ * used to submit our private bio
+ */
+static inline void drbd_generic_make_request(struct drbd_conf *mdev,
+					     int fault_type, struct bio *bio)
+{
+	__release(local);
+	if (!bio->bi_bdev) {
+		printk(KERN_ERR "drbd%d: drbd_generic_make_request: "
+				"bio->bi_bdev == NULL\n",
+		       mdev_to_minor(mdev));
+		dump_stack();
+		bio_endio(bio, -ENODEV);
+		return;
+	}
+
+	if (FAULT_ACTIVE(mdev, fault_type))
+		bio_endio(bio, -EIO);
+	else
+		generic_make_request(bio);
+}
+
+static inline void drbd_plug_device(struct drbd_conf *mdev)
+{
+	struct request_queue *q;
+	q = bdev_get_queue(mdev->this_bdev);
+
+	spin_lock_irq(q->queue_lock);
+
+/* XXX the check on !blk_queue_plugged is redundant,
+ * implicitly checked in blk_plug_device */
+
+	if (!blk_queue_plugged(q)) {
+		blk_plug_device(q);
+		del_timer(&q->unplug_timer);
+		/* unplugging should not happen automatically... */
+	}
+	spin_unlock_irq(q->queue_lock);
+}
+
+#ifndef __CHECKER__
+# undef __cond_lock
+# define __cond_lock(x,c) (c)
+#endif
+
--
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