dlm: core locking

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+/******************************************************************************
+*******************************************************************************
+**
+**  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_DOT_H__
+#define __DLM_DOT_H__
+
+/*
+ * Interface to DLM - routines and structures to use DLM lockspaces.
+ */
+
+/*
+ * Lock Modes
+ */
+
+#define DLM_LOCK_IV            (-1)	/* invalid */
+#define DLM_LOCK_NL            (0)	/* null */
+#define DLM_LOCK_CR            (1)	/* concurrent read */
+#define DLM_LOCK_CW            (2)	/* concurrent write */
+#define DLM_LOCK_PR            (3)	/* protected read */
+#define DLM_LOCK_PW            (4)	/* protected write */
+#define DLM_LOCK_EX            (5)	/* exclusive */
+
+/*
+ * Maximum size in bytes of a dlm_lock name
+ */
+
+#define DLM_RESNAME_MAXLEN     (64)
+
+/*
+ * Size in bytes of Lock Value Block
+ */
+
+#define DLM_LVB_LEN            (32)
+
+/*
+ * Flags to dlm_lock
+ *
+ * DLM_LKF_NOQUEUE
+ *
+ * Do not queue the lock request on the wait queue if it cannot be granted
+ * immediately.  If the lock cannot be granted because of this flag, DLM will
+ * either return -EAGAIN from the dlm_lock call or will return 0 from
+ * dlm_lock and -EAGAIN in the lock status block when the AST is executed.
+ *
+ * DLM_LKF_CANCEL
+ *
+ * Used to cancel a pending lock request or conversion.  A converting lock is
+ * returned to its previously granted mode.
+ *
+ * DLM_LKF_CONVERT
+ *
+ * Indicates a lock conversion request.  For conversions the name and namelen
+ * are ignored and the lock ID in the LKSB is used to identify the lock.
+ *
+ * DLM_LKF_VALBLK
+ *
+ * Requests DLM to return the current contents of the lock value block in the
+ * lock status block.  When this flag is set in a lock conversion from PW or EX
+ * modes, DLM assigns the value specified in the lock status block to the lock
+ * value block of the lock resource.  The LVB is a DLM_LVB_LEN size array
+ * containing application-specific information.
+ *
+ * DLM_LKF_QUECVT
+ *
+ * Force a conversion request to be queued, even if it is compatible with
+ * the granted modes of other locks on the same resource.
+ *
+ * DLM_LKF_IVVALBLK
+ *
+ * Invalidate the lock value block.
+ *
+ * DLM_LKF_CONVDEADLK
+ *
+ * Allows the dlm to resolve conversion deadlocks internally by demoting the
+ * granted mode of a converting lock to NL.  The DLM_SBF_DEMOTED flag is
+ * returned for a conversion that's been effected by this.
+ *
+ * DLM_LKF_PERSISTENT
+ *
+ * Only relevant to locks originating in userspace.  A persistent lock will not
+ * be removed if the process holding the lock exits.
+ *
+ * DLM_LKF_NODLKWT
+ * DLM_LKF_NODLCKBLK
+ *
+ * net yet implemented
+ *
+ * DLM_LKF_EXPEDITE
+ *
+ * Used only with new requests for NL mode locks.  Tells the lock manager
+ * to grant the lock, ignoring other locks in convert and wait queues.
+ *
+ * DLM_LKF_NOQUEUEBAST
+ *
+ * Send blocking AST's before returning -EAGAIN to the caller.  It is only
+ * used along with the NOQUEUE flag.  Blocking AST's are not sent for failed
+ * NOQUEUE requests otherwise.
+ *
+ * DLM_LKF_HEADQUE
+ *
+ * Add a lock to the head of the convert or wait queue rather than the tail.
+ *
+ * DLM_LKF_NOORDER
+ *
+ * Disregard the standard grant order rules and grant a lock as soon as it
+ * is compatible with other granted locks.
+ *
+ * DLM_LKF_ORPHAN
+ *
+ * not yet implemented
+ *
+ * DLM_LKF_ALTPR
+ *
+ * If the requested mode cannot be granted immediately, try to grant the lock
+ * in PR mode instead.  If this alternate mode is granted instead of the
+ * requested mode, DLM_SBF_ALTMODE is returned in the lksb.
+ *
+ * DLM_LKF_ALTCW
+ *
+ * The same as ALTPR, but the alternate mode is CW.
+ */
+
+#define DLM_LKF_NOQUEUE        (0x00000001)
+#define DLM_LKF_CANCEL         (0x00000002)
+#define DLM_LKF_CONVERT        (0x00000004)
+#define DLM_LKF_VALBLK         (0x00000008)
+#define DLM_LKF_QUECVT         (0x00000010)
+#define DLM_LKF_IVVALBLK       (0x00000020)
+#define DLM_LKF_CONVDEADLK     (0x00000040)
+#define DLM_LKF_PERSISTENT     (0x00000080)
+#define DLM_LKF_NODLCKWT       (0x00000100)
+#define DLM_LKF_NODLCKBLK      (0x00000200)
+#define DLM_LKF_EXPEDITE       (0x00000400)
+#define DLM_LKF_NOQUEUEBAST    (0x00000800)
+#define DLM_LKF_HEADQUE        (0x00001000)
+#define DLM_LKF_NOORDER        (0x00002000)
+#define DLM_LKF_ORPHAN         (0x00004000)
+#define DLM_LKF_ALTPR          (0x00008000)
+#define DLM_LKF_ALTCW          (0x00010000)
+
+/*
+ * Some return codes that are not in errno.h
+ */
+
+#define DLM_ECANCEL            (0x10001)
+#define DLM_EUNLOCK            (0x10002)
+
+typedef void dlm_lockspace_t;
+
+/*
+ * Lock range structure
+ */
+
+struct dlm_range {
+	uint64_t ra_start;
+	uint64_t ra_end;
+};
+
+/*
+ * Lock status block
+ *
+ * Use this structure to specify the contents of the lock value block.  For a
+ * conversion request, this structure is used to specify the lock ID of the
+ * lock.  DLM writes the status of the lock request and the lock ID assigned
+ * to the request in the lock status block.
+ *
+ * sb_lkid: the returned lock ID.  It is set on new (non-conversion) requests.
+ * It is available when dlm_lock returns.
+ *
+ * sb_lvbptr: saves or returns the contents of the lock's LVB according to rules
+ * shown for the DLM_LKF_VALBLK flag.
+ *
+ * sb_flags: DLM_SBF_DEMOTED is returned if in the process of promoting a lock,
+ * it was first demoted to NL to avoid conversion deadlock.
+ * DLM_SBF_VALNOTVALID is returned if the resource's LVB is marked invalid.
+ *
+ * sb_status: the returned status of the lock request set prior to AST
+ * execution.  Possible return values:
+ *
+ * 0 if lock request was successful
+ * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
+ * -ENOMEM if there is no memory to process request
+ * -EINVAL if there are invalid parameters
+ * -DLM_EUNLOCK if unlock request was successful
+ * -DLM_ECANCEL if a cancel completed successfully
+ */
+
+#define DLM_SBF_DEMOTED        (0x01)
+#define DLM_SBF_VALNOTVALID    (0x02)
+#define DLM_SBF_ALTMODE        (0x04)
+
+struct dlm_lksb {
+	int 	 sb_status;
+	uint32_t sb_lkid;
+	char 	 sb_flags;
+	char *	 sb_lvbptr;
+};
+
+
+#ifdef __KERNEL__
+
+/*
+ * dlm_new_lockspace
+ *
+ * Starts a lockspace with the given name.  If the named lockspace exists in
+ * the cluster, the calling node joins it.
+ */
+
+int dlm_new_lockspace(char *name, int namelen, dlm_lockspace_t **lockspace,
+		      int flags);
+
+/*
+ * dlm_release_lockspace
+ *
+ * Stop a lockspace.
+ */
+
+int dlm_release_lockspace(dlm_lockspace_t *lockspace, int force);
+
+/*
+ * dlm_lock
+ *
+ * Make an asyncronous request to acquire or convert a lock on a named
+ * resource.
+ *
+ * lockspace: context for the request
+ * mode: the requested mode of the lock (DLM_LOCK_)
+ * lksb: lock status block for input and async return values
+ * flags: input flags (DLM_LKF_)
+ * name: name of the resource to lock, can be binary
+ * namelen: the length in bytes of the resource name (MAX_RESNAME_LEN)
+ * parent: the lock ID of a parent lock or 0 if none
+ * lockast: function DLM executes when it completes processing the request
+ * astarg: argument passed to lockast and bast functions
+ * bast: function DLM executes when this lock later blocks another request
+ *
+ * Returns:
+ * 0 if request is successfully queued for processing
+ * -EINVAL if any input parameters are invalid
+ * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
+ * -ENOMEM if there is no memory to process request
+ * -ENOTCONN if there is a communication error
+ *
+ * If the call to dlm_lock returns an error then the operation has failed and
+ * the AST routine will not be called.  If dlm_lock returns 0 it is still
+ * possible that the lock operation will fail. The AST routine will be called
+ * when the locking is complete and the status is returned in the lksb.
+ *
+ * If the AST routines or parameter are passed to a conversion operation then
+ * they will overwrite those values that were passed to a previous dlm_lock
+ * call.
+ *
+ * AST routines should not block (at least not for long), but may make
+ * any locking calls they please.
+ */
+
+int dlm_lock(dlm_lockspace_t *lockspace,
+	     int mode,
+	     struct dlm_lksb *lksb,
+	     uint32_t flags,
+	     void *name,
+	     unsigned int namelen,
+	     uint32_t parent_lkid,
+	     void (*lockast) (void *astarg),
+	     void *astarg,
+	     void (*bast) (void *astarg, int mode),
+	     struct dlm_range *range);
+
+/*
+ * dlm_unlock
+ *
+ * Asynchronously release a lock on a resource.  The AST routine is called
+ * when the resource is successfully unlocked.
+ *
+ * lockspace: context for the request
+ * lkid: the lock ID as returned in the lksb
+ * flags: input flags (DLM_LKF_)
+ * lksb: if NULL the lksb parameter passed to last lock request is used
+ * astarg: the arg used with the completion ast for the unlock
+ *
+ * Returns:
+ * 0 if request is successfully queued for processing
+ * -EINVAL if any input parameters are invalid
+ * -ENOTEMPTY if the lock still has sublocks
+ * -EBUSY if the lock is waiting for a remote lock operation
+ * -ENOTCONN if there is a communication error
+ */
+
+int dlm_unlock(dlm_lockspace_t *lockspace,
+	       uint32_t lkid,
+	       uint32_t flags,
+	       struct dlm_lksb *lksb,
+	       void *astarg);
+
+#endif				/* __KERNEL__ */
+
+#endif				/* __DLM_DOT_H__ */

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+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) 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 __LVB_TABLE_DOT_H__
+#define __LVB_TABLE_DOT_H__
+
+/*
+ * This defines the direction of transfer of LVB data.
+ * Granted mode is the row; requested mode is the column.
+ * Usage: matrix[grmode+1][rqmode+1]
+ * 1 = LVB is returned to the caller
+ * 0 = LVB is written to the resource
+ * -1 = nothing happens to the LVB
+ */
+
+const int dlm_lvb_operations[8][8] = {
+        /* UN   NL  CR  CW  PR  PW  EX  PD*/
+        {  -1,  1,  1,  1,  1,  1,  1, -1 }, /* UN */
+        {  -1,  1,  1,  1,  1,  1,  1,  0 }, /* NL */
+        {  -1, -1,  1,  1,  1,  1,  1,  0 }, /* CR */
+        {  -1, -1, -1,  1,  1,  1,  1,  0 }, /* CW */
+        {  -1, -1, -1, -1,  1,  1,  1,  0 }, /* PR */
+        {  -1,  0,  0,  0,  0,  0,  1,  0 }, /* PW */
+        {  -1,  0,  0,  0,  0,  0,  0,  0 }, /* EX */
+        {  -1,  0,  0,  0,  0,  0,  0,  0 }  /* PD */
+};
+
+#endif

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+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) 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 __ASTD_DOT_H__
+#define __ASTD_DOT_H__
+
+void dlm_add_ast(struct dlm_lkb *lkb, int type);
+void dlm_del_ast(struct dlm_lkb *lkb);
+
+void dlm_astd_wake(void);
+int dlm_astd_start(void);
+void dlm_astd_stop(void);
+void dlm_astd_suspend(void);
+void dlm_astd_resume(void);
+
+#endif
+

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+/******************************************************************************
+*******************************************************************************
+**
+**  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 __DIR_DOT_H__
+#define __DIR_DOT_H__
+
+
+int dlm_dir_nodeid(struct dlm_rsb *rsb);
+int dlm_dir_name2nodeid(struct dlm_ls *ls, char *name, int length);
+void dlm_dir_remove_entry(struct dlm_ls *ls, int nodeid, char *name, int len);
+void dlm_dir_clear(struct dlm_ls *ls);
+void dlm_clear_free_entries(struct dlm_ls *ls);
+int dlm_recover_directory(struct dlm_ls *ls);
+int dlm_dir_lookup(struct dlm_ls *ls, int nodeid, char *name, int namelen,
+	int *r_nodeid);
+int dlm_copy_master_names(struct dlm_ls *ls, char *inbuf, int inlen,
+	char *outbuf, int outlen, int nodeid);
+int dlm_dir_rebuild_wait(struct dlm_ls *ls);
+
+#endif				/* __DIR_DOT_H__ */

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+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) 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 __LOCK_DOT_H__
+#define __LOCK_DOT_H__
+
+void dlm_print_lkb(struct dlm_lkb *lkb);
+void dlm_print_rsb(struct dlm_rsb *r);
+int dlm_receive_message(struct dlm_header *hd, int nodeid, int recovery);
+int dlm_modes_compat(int mode1, int mode2);
+int dlm_find_rsb(struct dlm_ls *ls, char *name, int namelen,
+	unsigned int flags, struct dlm_rsb **r_ret);
+int dlm_is_master(struct dlm_rsb *r);
+void dlm_put_rsb(struct dlm_rsb *r);
+void dlm_hold_rsb(struct dlm_rsb *r);
+void dlm_lock_rsb(struct dlm_rsb *r);
+void dlm_unlock_rsb(struct dlm_rsb *r);
+int dlm_put_lkb(struct dlm_lkb *lkb);
+int dlm_remove_from_waiters(struct dlm_lkb *lkb);
+void dlm_scan_rsbs(struct dlm_ls *ls);
+
+int dlm_purge_locks(struct dlm_ls *ls);
+int dlm_grant_after_purge(struct dlm_ls *ls);
+int dlm_recover_waiters_post(struct dlm_ls *ls);
+void dlm_recover_waiters_pre(struct dlm_ls *ls);
+int dlm_recover_master_copy(struct dlm_ls *ls, struct dlm_rcom *rc);
+int dlm_recover_process_copy(struct dlm_ls *ls, struct dlm_rcom *rc);
+
+#endif

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+/******************************************************************************
+*******************************************************************************
+**
+**  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 __LOCKSPACE_DOT_H__
+#define __LOCKSPACE_DOT_H__
+
+int dlm_lockspace_init(void);
+void dlm_lockspace_exit(void);
+int dlm_new_lockspace(char *name, int namelen, void **ls, int flags);
+int dlm_release_lockspace(void *ls, int force);
+struct dlm_ls *dlm_find_lockspace_global(uint32_t id);
+struct dlm_ls *dlm_find_lockspace_local(void *id);
+struct dlm_ls *dlm_find_lockspace_name(char *name, int namelen);
+void dlm_put_lockspace(struct dlm_ls *ls);
+
+#endif				/* __LOCKSPACE_DOT_H__ */

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+/******************************************************************************
+*******************************************************************************
+**
+**  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 __MEMORY_DOT_H__
+#define __MEMORY_DOT_H__
+
+int dlm_memory_init(void);
+void dlm_memory_exit(void);
+struct dlm_rsb *allocate_rsb(struct dlm_ls *ls, int namelen);
+void free_rsb(struct dlm_rsb *r);
+struct dlm_lkb *allocate_lkb(struct dlm_ls *ls);
+void free_lkb(struct dlm_lkb *l);
+struct dlm_direntry *allocate_direntry(struct dlm_ls *ls, int namelen);
+void free_direntry(struct dlm_direntry *de);
+char *allocate_lvb(struct dlm_ls *ls);
+void free_lvb(char *l);
+uint64_t *allocate_range(struct dlm_ls *ls);
+void free_range(uint64_t *l);
+
+#endif		/* __MEMORY_DOT_H__ */

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+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) 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 __UTIL_DOT_H__
+#define __UTIL_DOT_H__
+
+uint32_t dlm_hash(const char *data, int len);
+
+void dlm_message_out(struct dlm_message *ms);
+void dlm_message_in(struct dlm_message *ms);
+void dlm_rcom_out(struct dlm_rcom *rc);
+void dlm_rcom_in(struct dlm_rcom *rc);
+
+#endif