[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__ */
+