[DLM] The core of the DLM for GFS2/CLVM

This is the core of the distributed lock manager which is required
to use GFS2 as a cluster filesystem. It is also used by CLVM and
can be used as a standalone lock manager independantly of either
of these two projects.

It implements VAX-style locking modes.

Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steve Whitehouse <swhiteho@redhat.com>

1 files changed, 518 insertions, 0 deletions

diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
new file mode 100644
index 000000000000..0020cd07baf7
--- /dev/null
+++ b/fs/dlm/dlm_internal.h
@@ -0,0 +1,518 @@
+/******************************************************************************
+*******************************************************************************
+**
+**  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 <asm/semaphore.h>
+#include <asm/uaccess.h>
+
+#include <linux/dlm.h>
+
+#define DLM_LOCKSPACE_LEN	64
+
+#ifndef TRUE
+#define TRUE 1
+#endif
+
+#ifndef FALSE
+#define FALSE 0
+#endif
+
+#if (BITS_PER_LONG == 64)
+#define PRIx64 "lx"
+#else
+#define PRIx64 "Lx"
+#endif
+
+/* 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)
+
+#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;
+	struct dlm_range	*range;
+};
+
+
+/*
+ * 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_range[] */
+
+#define GR_RANGE_START		0
+#define GR_RANGE_END		1
+#define RQ_RANGE_START		2
+#define RQ_RANGE_END		3
+
+/* 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_RANGE		0x00000001
+
+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 */
+
+	uint64_t		*lkb_range;	/* array of gr/rq ranges */
+	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 semaphore	res_sem;
+	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,
+};
+
+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 */
+	uint64_t		m_range[2];
+	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;
+	uint64_t		rl_range[4];
+	char			rl_name[DLM_RESNAME_MAXLEN];
+	char			rl_lvb[0];
+};
+
+struct dlm_ls {
+	struct list_head	ls_list;	/* list of lockspaces */
+	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 semaphore	ls_waiters_sem;
+	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_dentry; /* debugfs */
+
+	wait_queue_head_t	ls_uevent_wait;	/* user part of join/leave */
+	int			ls_uevent_result;
+
+	/* recovery related */
+
+	struct timer_list	ls_timer;
+	struct task_struct	*ls_recoverd_task;
+	struct semaphore	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 semaphore	ls_requestqueue_lock;
+	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 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
+
+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__ */
+