dlm_internal.h

/******************************************************************************
*******************************************************************************
**
**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
**
**  This copyrighted material is made available to anyone wishing to use,
**  modify, copy, or redistribute it subject to the terms and conditions
**  of the GNU General Public License v.2.
**
*******************************************************************************
******************************************************************************/

#ifndef __DLM_INTERNAL_DOT_H__
#define __DLM_INTERNAL_DOT_H__

/*
 * This is the main header file to be included in each DLM source file.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/ctype.h>
#include <linux/spinlock.h>
#include <linux/vmalloc.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/random.h>
#include <linux/delay.h>
#include <linux/socket.h>
#include <linux/kthread.h>
#include <linux/kobject.h>
#include <linux/kref.h>
#include <linux/kernel.h>
#include <linux/jhash.h>
#include <linux/miscdevice.h>
#include <linux/mutex.h>
#include <asm/semaphore.h>
#include <asm/uaccess.h>

#include <linux/dlm.h>

#define DLM_LOCKSPACE_LEN	64

/* Size of the temp buffer midcomms allocates on the stack.
   We try to make this large enough so most messages fit.
   FIXME: should sctp make this unnecessary? */

#define DLM_INBUF_LEN		148

struct dlm_ls;
struct dlm_lkb;
struct dlm_rsb;
struct dlm_member;
struct dlm_lkbtable;
struct dlm_rsbtable;
struct dlm_dirtable;
struct dlm_direntry;
struct dlm_recover;
struct dlm_header;
struct dlm_message;
struct dlm_rcom;
struct dlm_mhandle;

#define log_print(fmt, args...) \
	printk(KERN_ERR "dlm: "fmt"\n" , ##args)
#define log_error(ls, fmt, args...) \
	printk(KERN_ERR "dlm: %s: " fmt "\n", (ls)->ls_name , ##args)

#define DLM_LOG_DEBUG
#ifdef DLM_LOG_DEBUG
#define log_debug(ls, fmt, args...) log_error(ls, fmt, ##args)
#else
#define log_debug(ls, fmt, args...)
#endif

#define DLM_ASSERT(x, do) \
{ \
  if (!(x)) \
  { \
    printk(KERN_ERR "\nDLM:  Assertion failed on line %d of file %s\n" \
               "DLM:  assertion:  \"%s\"\n" \
               "DLM:  time = %lu\n", \
               __LINE__, __FILE__, #x, jiffies); \
    {do} \
    printk("\n"); \
    BUG(); \
    panic("DLM:  Record message above and reboot.\n"); \
  } \
}


struct dlm_direntry {
	struct list_head	list;
	uint32_t		master_nodeid;
	uint16_t		length;
	char			name[1];
};

struct dlm_dirtable {
	struct list_head	list;
	rwlock_t		lock;
};

struct dlm_rsbtable {
	struct list_head	list;
	struct list_head	toss;
	rwlock_t		lock;
};

struct dlm_lkbtable {
	struct list_head	list;
	rwlock_t		lock;
	uint16_t		counter;
};

/*
 * Lockspace member (per node in a ls)
 */

struct dlm_member {
	struct list_head	list;
	int			nodeid;
	int			weight;
};

/*
 * Save and manage recovery state for a lockspace.
 */

struct dlm_recover {
	struct list_head	list;
	int			*nodeids;
	int			node_count;
	uint64_t		seq;
};

/*
 * Pass input args to second stage locking function.
 */

struct dlm_args {
	uint32_t		flags;
	void			*astaddr;
	long			astparam;
	void			*bastaddr;
	int			mode;
	struct dlm_lksb		*lksb;
};


/*
 * Lock block
 *
 * A lock can be one of three types:
 *
 * local copy      lock is mastered locally
 *                 (lkb_nodeid is zero and DLM_LKF_MSTCPY is not set)
 * process copy    lock is mastered on a remote node
 *                 (lkb_nodeid is non-zero and DLM_LKF_MSTCPY is not set)
 * master copy     master node's copy of a lock owned by remote node
 *                 (lkb_nodeid is non-zero and DLM_LKF_MSTCPY is set)
 *
 * lkb_exflags: a copy of the most recent flags arg provided to dlm_lock or
 * dlm_unlock.  The dlm does not modify these or use any private flags in
 * this field; it only contains DLM_LKF_ flags from dlm.h.  These flags
 * are sent as-is to the remote master when the lock is remote.
 *
 * lkb_flags: internal dlm flags (DLM_IFL_ prefix) from dlm_internal.h.
 * Some internal flags are shared between the master and process nodes;
 * these shared flags are kept in the lower two bytes.  One of these
 * flags set on the master copy will be propagated to the process copy
 * and v.v.  Other internal flags are private to the master or process
 * node (e.g. DLM_IFL_MSTCPY).  These are kept in the high two bytes.
 *
 * lkb_sbflags: status block flags.  These flags are copied directly into
 * the caller's lksb.sb_flags prior to the dlm_lock/dlm_unlock completion
 * ast.  All defined in dlm.h with DLM_SBF_ prefix.
 *
 * lkb_status: the lock status indicates which rsb queue the lock is
 * on, grant, convert, or wait.  DLM_LKSTS_ WAITING/GRANTED/CONVERT
 *
 * lkb_wait_type: the dlm message type (DLM_MSG_ prefix) for which a
 * reply is needed.  Only set when the lkb is on the lockspace waiters
 * list awaiting a reply from a remote node.
 *
 * lkb_nodeid: when the lkb is a local copy, nodeid is 0; when the lkb
 * is a master copy, nodeid specifies the remote lock holder, when the
 * lkb is a process copy, the nodeid specifies the lock master.
 */

/* lkb_ast_type */

#define AST_COMP		1
#define AST_BAST		2

/* lkb_status */

#define DLM_LKSTS_WAITING	1
#define DLM_LKSTS_GRANTED	2
#define DLM_LKSTS_CONVERT	3

/* lkb_flags */

#define DLM_IFL_MSTCPY		0x00010000
#define DLM_IFL_RESEND		0x00020000
#define DLM_IFL_DEAD		0x00040000
#define DLM_IFL_USER		0x00000001
#define DLM_IFL_ORPHAN		0x00000002

struct dlm_lkb {
	struct dlm_rsb		*lkb_resource;	/* the rsb */
	struct kref		lkb_ref;
	int			lkb_nodeid;	/* copied from rsb */
	int			lkb_ownpid;	/* pid of lock owner */
	uint32_t		lkb_id;		/* our lock ID */
	uint32_t		lkb_remid;	/* lock ID on remote partner */
	uint32_t		lkb_exflags;	/* external flags from caller */
	uint32_t		lkb_sbflags;	/* lksb flags */
	uint32_t		lkb_flags;	/* internal flags */
	uint32_t		lkb_lvbseq;	/* lvb sequence number */

	int8_t			lkb_status;     /* granted, waiting, convert */
	int8_t			lkb_rqmode;	/* requested lock mode */
	int8_t			lkb_grmode;	/* granted lock mode */
	int8_t			lkb_bastmode;	/* requested mode */
	int8_t			lkb_highbast;	/* highest mode bast sent for */

	int8_t			lkb_wait_type;	/* type of reply waiting for */
	int8_t			lkb_ast_type;	/* type of ast queued for */

	struct list_head	lkb_idtbl_list;	/* lockspace lkbtbl */
	struct list_head	lkb_statequeue;	/* rsb g/c/w list */
	struct list_head	lkb_rsb_lookup;	/* waiting for rsb lookup */
	struct list_head	lkb_wait_reply;	/* waiting for remote reply */
	struct list_head	lkb_astqueue;	/* need ast to be sent */
	struct list_head	lkb_ownqueue;	/* list of locks for a process */

	char			*lkb_lvbptr;
	struct dlm_lksb		*lkb_lksb;      /* caller's status block */
	void			*lkb_astaddr;	/* caller's ast function */
	void			*lkb_bastaddr;	/* caller's bast function */
	long			lkb_astparam;	/* caller's ast arg */
};


struct dlm_rsb {
	struct dlm_ls		*res_ls;	/* the lockspace */
	struct kref		res_ref;
	struct mutex		res_mutex;
	unsigned long		res_flags;
	int			res_length;	/* length of rsb name */
	int			res_nodeid;
	uint32_t                res_lvbseq;
	uint32_t		res_hash;
	uint32_t		res_bucket;	/* rsbtbl */
	unsigned long		res_toss_time;
	uint32_t		res_first_lkid;
	struct list_head	res_lookup;	/* lkbs waiting on first */
	struct list_head	res_hashchain;	/* rsbtbl */
	struct list_head	res_grantqueue;
	struct list_head	res_convertqueue;
	struct list_head	res_waitqueue;

	struct list_head	res_root_list;	    /* used for recovery */
	struct list_head	res_recover_list;   /* used for recovery */
	int			res_recover_locks_count;

	char			*res_lvbptr;
	char			res_name[1];
};

/* find_rsb() flags */

#define R_MASTER		1	/* only return rsb if it's a master */
#define R_CREATE		2	/* create/add rsb if not found */

/* rsb_flags */

enum rsb_flags {
	RSB_MASTER_UNCERTAIN,
	RSB_VALNOTVALID,
	RSB_VALNOTVALID_PREV,
	RSB_NEW_MASTER,
	RSB_NEW_MASTER2,
	RSB_RECOVER_CONVERT,
	RSB_LOCKS_PURGED,
};

static inline void rsb_set_flag(struct dlm_rsb *r, enum rsb_flags flag)
{
	__set_bit(flag, &r->res_flags);
}

static inline void rsb_clear_flag(struct dlm_rsb *r, enum rsb_flags flag)
{
	__clear_bit(flag, &r->res_flags);
}

static inline int rsb_flag(struct dlm_rsb *r, enum rsb_flags flag)
{
	return test_bit(flag, &r->res_flags);
}


/* dlm_header is first element of all structs sent between nodes */

#define DLM_HEADER_MAJOR	0x00020000
#define DLM_HEADER_MINOR	0x00000001

#define DLM_MSG			1
#define DLM_RCOM		2

struct dlm_header {
	uint32_t		h_version;
	uint32_t		h_lockspace;
	uint32_t		h_nodeid;	/* nodeid of sender */
	uint16_t		h_length;
	uint8_t			h_cmd;		/* DLM_MSG, DLM_RCOM */
	uint8_t			h_pad;
};


#define DLM_MSG_REQUEST		1
#define DLM_MSG_CONVERT		2
#define DLM_MSG_UNLOCK		3
#define DLM_MSG_CANCEL		4
#define DLM_MSG_REQUEST_REPLY	5
#define DLM_MSG_CONVERT_REPLY	6
#define DLM_MSG_UNLOCK_REPLY	7
#define DLM_MSG_CANCEL_REPLY	8
#define DLM_MSG_GRANT		9
#define DLM_MSG_BAST		10
#define DLM_MSG_LOOKUP		11
#define DLM_MSG_REMOVE		12
#define DLM_MSG_LOOKUP_REPLY	13

struct dlm_message {
	struct dlm_header	m_header;
	uint32_t		m_type;		/* DLM_MSG_ */
	uint32_t		m_nodeid;
	uint32_t		m_pid;
	uint32_t		m_lkid;		/* lkid on sender */
	uint32_t		m_remid;	/* lkid on receiver */
	uint32_t		m_parent_lkid;
	uint32_t		m_parent_remid;
	uint32_t		m_exflags;
	uint32_t		m_sbflags;
	uint32_t		m_flags;
	uint32_t		m_lvbseq;
	uint32_t		m_hash;
	int			m_status;
	int			m_grmode;
	int			m_rqmode;
	int			m_bastmode;
	int			m_asts;
	int			m_result;	/* 0 or -EXXX */
	char			m_extra[0];	/* name or lvb */
};


#define DLM_RS_NODES		0x00000001
#define DLM_RS_NODES_ALL	0x00000002
#define DLM_RS_DIR		0x00000004
#define DLM_RS_DIR_ALL		0x00000008
#define DLM_RS_LOCKS		0x00000010
#define DLM_RS_LOCKS_ALL	0x00000020
#define DLM_RS_DONE		0x00000040
#define DLM_RS_DONE_ALL		0x00000080

#define DLM_RCOM_STATUS		1
#define DLM_RCOM_NAMES		2
#define DLM_RCOM_LOOKUP		3
#define DLM_RCOM_LOCK		4
#define DLM_RCOM_STATUS_REPLY	5
#define DLM_RCOM_NAMES_REPLY	6
#define DLM_RCOM_LOOKUP_REPLY	7
#define DLM_RCOM_LOCK_REPLY	8

struct dlm_rcom {
	struct dlm_header	rc_header;
	uint32_t		rc_type;	/* DLM_RCOM_ */
	int			rc_result;	/* multi-purpose */
	uint64_t		rc_id;		/* match reply with request */
	char			rc_buf[0];
};

struct rcom_config {
	uint32_t		rf_lvblen;
	uint32_t		rf_lsflags;
	uint64_t		rf_unused;
};

struct rcom_lock {
	uint32_t		rl_ownpid;
	uint32_t		rl_lkid;
	uint32_t		rl_remid;
	uint32_t		rl_parent_lkid;
	uint32_t		rl_parent_remid;
	uint32_t		rl_exflags;
	uint32_t		rl_flags;
	uint32_t		rl_lvbseq;
	int			rl_result;
	int8_t			rl_rqmode;
	int8_t			rl_grmode;
	int8_t			rl_status;
	int8_t			rl_asts;
	uint16_t		rl_wait_type;
	uint16_t		rl_namelen;
	char			rl_name[DLM_RESNAME_MAXLEN];
	char			rl_lvb[0];
};

struct dlm_ls {
	struct list_head	ls_list;	/* list of lockspaces */
	dlm_lockspace_t		*ls_local_handle;
	uint32_t		ls_global_id;	/* global unique lockspace ID */
	uint32_t		ls_exflags;
	int			ls_lvblen;
	int			ls_count;	/* reference count */
	unsigned long		ls_flags;	/* LSFL_ */
	struct kobject		ls_kobj;

	struct dlm_rsbtable	*ls_rsbtbl;
	uint32_t		ls_rsbtbl_size;

	struct dlm_lkbtable	*ls_lkbtbl;
	uint32_t		ls_lkbtbl_size;

	struct dlm_dirtable	*ls_dirtbl;
	uint32_t		ls_dirtbl_size;

	struct mutex		ls_waiters_mutex;
	struct list_head	ls_waiters;	/* lkbs needing a reply */

	struct list_head	ls_nodes;	/* current nodes in ls */
	struct list_head	ls_nodes_gone;	/* dead node list, recovery */
	int			ls_num_nodes;	/* number of nodes in ls */
	int			ls_low_nodeid;
	int			ls_total_weight;
	int			*ls_node_array;

	struct dlm_rsb		ls_stub_rsb;	/* for returning errors */
	struct dlm_lkb		ls_stub_lkb;	/* for returning errors */
	struct dlm_message	ls_stub_ms;	/* for faking a reply */

	struct dentry		*ls_debug_rsb_dentry; /* debugfs */
	struct dentry		*ls_debug_waiters_dentry; /* debugfs */

	wait_queue_head_t	ls_uevent_wait;	/* user part of join/leave */
	int			ls_uevent_result;

	struct miscdevice       ls_device;

	/* recovery related */

	struct timer_list	ls_timer;
	struct task_struct	*ls_recoverd_task;
	struct mutex		ls_recoverd_active;
	spinlock_t		ls_recover_lock;
	uint32_t		ls_recover_status; /* DLM_RS_ */
	uint64_t		ls_recover_seq;
	struct dlm_recover	*ls_recover_args;
	struct rw_semaphore	ls_in_recovery;	/* block local requests */
	struct list_head	ls_requestqueue;/* queue remote requests */
	struct mutex		ls_requestqueue_mutex;
	char			*ls_recover_buf;
	struct list_head	ls_recover_list;
	spinlock_t		ls_recover_list_lock;
	int			ls_recover_list_count;
	wait_queue_head_t	ls_wait_general;
	struct mutex		ls_clear_proc_locks;

	struct list_head	ls_root_list;	/* root resources */
	struct rw_semaphore	ls_root_sem;	/* protect root_list */

	int			ls_namelen;
	char			ls_name[1];
};

#define LSFL_WORK		0
#define LSFL_RUNNING		1
#define LSFL_RECOVERY_STOP	2
#define LSFL_RCOM_READY		3
#define LSFL_UEVENT_WAIT	4

/* much of this is just saving user space pointers associated with the
   lock that we pass back to the user lib with an ast */

struct dlm_user_args {
	struct dlm_user_proc	*proc; /* each process that opens the lockspace
					  device has private data
					  (dlm_user_proc) on the struct file,
					  the process's locks point back to it*/
	struct dlm_lksb		lksb;
	int			old_mode;
	int			update_user_lvb;
	struct dlm_lksb __user	*user_lksb;
	void __user		*castparam;
	void __user		*castaddr;
	void __user		*bastparam;
	void __user		*bastaddr;
};

#define DLM_PROC_FLAGS_CLOSING 1
#define DLM_PROC_FLAGS_COMPAT  2

/* locks list is kept so we can remove all a process's locks when it
   exits (or orphan those that are persistent) */

struct dlm_user_proc {
	dlm_lockspace_t		*lockspace;
	unsigned long		flags; /* DLM_PROC_FLAGS */
	struct list_head	asts;
	spinlock_t		asts_spin;
	struct list_head	locks;
	spinlock_t		locks_spin;
	wait_queue_head_t	wait;
};

static inline int dlm_locking_stopped(struct dlm_ls *ls)
{
	return !test_bit(LSFL_RUNNING, &ls->ls_flags);
}

static inline int dlm_recovery_stopped(struct dlm_ls *ls)
{
	return test_bit(LSFL_RECOVERY_STOP, &ls->ls_flags);
}

static inline int dlm_no_directory(struct dlm_ls *ls)
{
	return (ls->ls_exflags & DLM_LSFL_NODIR) ? 1 : 0;
}

#endif				/* __DLM_INTERNAL_DOT_H__ */