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    Subject[PATCH 06/12] DRBD: internal_data_structures
    Date
    The big "struct drbd_conf". It actually describes one DRBD device.

    ---
    diff -uNrp linux-2.6.29-rc8/drivers/block/drbd/drbd_int.h linux-2.6.29-rc8-drbd/drivers/block/drbd/drbd_int.h
    --- linux-2.6.29-rc8/drivers/block/drbd/drbd_int.h 1970-01-01 01:00:00.000000000 +0100
    +++ linux-2.6.29-rc8-drbd/drivers/block/drbd/drbd_int.h 2009-03-23 12:45:27.837529608 +0100
    @@ -0,0 +1,2219 @@
    +/*
    + drbd_int.h
    + Kernel module for 2.6.x Kernels
    +
    + 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@linbit.com>.
    + Copyright (C) 2002-2008, Lars Ellenberg <lars.ellenberg@linbit.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)
    +
    +/* see kernel/printk.c:printk_ratelimit
    + * macro, so it is easy do have independend rate limits at different locations
    + * "initializer element not constant ..." with kernel 2.4 :(
    + * so I initialize toks to something large
    + */
    +#define DRBD_ratelimit(ratelimit_jiffies, ratelimit_burst) \
    +({ \
    + int __ret; \
    + static unsigned long toks = 0x80000000UL; \
    + static unsigned long last_msg; \
    + static int missed; \
    + unsigned long now = jiffies; \
    + toks += now - last_msg; \
    + last_msg = now; \
    + if (toks > (ratelimit_burst * ratelimit_jiffies)) \
    + toks = ratelimit_burst * ratelimit_jiffies; \
    + if (toks >= ratelimit_jiffies) { \
    + int lost = missed; \
    + missed = 0; \
    + toks -= ratelimit_jiffies; \
    + if (lost) \
    + drbd_WARN("%d messages suppressed in %s:%d.\n", \
    + lost, __FILE__, __LINE__); \
    + __ret = 1; \
    + } else { \
    + missed++; \
    + __ret = 0; \
    + } \
    + __ret; \
    +})
    +
    +
    +#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;
    +
    +/***
    + * 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 */
    +
    + MAX_CMD = 0x24,
    + 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",
    + [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];
    +}
    +
    +
    +/* 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 */
    + char 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)
    + */
    +
    +/* 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));
    +
    +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;
    + 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. */
    +};
    +
    +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;
    +
    + /* 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)
    +
    +/* I want the packet to fit within one page
    + * THINK maybe use a special bitmap header,
    + * including offset and compression scheme and whatnot
    + * Do not use PAGE_SIZE here! Use a architecture agnostic constant!
    + */
    +#define BM_PACKET_WORDS ((4096-sizeof(struct Drbd_Header))/sizeof(long))
    +#if (PAGE_SIZE < 4096)
    +/* drbd_send_bitmap / receive_bitmap would break horribly */
    +#error "PAGE_SIZE too small"
    +#endif
    +
    +/* 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 void drbd_bm_reset_find(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);
    +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);
    +extern void drbd_bm_set_find(struct drbd_conf *mdev, unsigned long i);
    +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 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_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 (DRBD_ratelimit(5*HZ, 5)) {
    + 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 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-rc8/drivers/block/drbd/drbd_wrappers.h linux-2.6.29-rc8-drbd/drivers/block/drbd/drbd_wrappers.h
    --- linux-2.6.29-rc8/drivers/block/drbd/drbd_wrappers.h 1970-01-01 01:00:00.000000000 +0100
    +++ linux-2.6.29-rc8-drbd/drivers/block/drbd/drbd_wrappers.h 2009-03-23 11:25:50.799275000 +0100
    @@ -0,0 +1,87 @@
    +#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);
    +
    +/*
    + * 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
    +

    \
     
     \ /
      Last update: 2009-03-23 17:01    [W:0.155 / U:89.808 seconds]
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