/******************************************************************************
*******************************************************************************
**
** 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 Distributed Lock Manager (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
/*
* 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.
*
* DLM_LKF_FORCEUNLOCK
*
* Unlock the lock even if it is converting or waiting or has sublocks.
* Only really for use by the userland device.c code.
*
*/
#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
#define DLM_LKF_FORCEUNLOCK 0x00020000
/*
* Some return codes that are not in errno.h
*/
#define DLM_ECANCEL 0x10001
#define DLM_EUNLOCK 0x10002
typedef void dlm_lockspace_t;
/*
* 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__
#define DLM_LSFL_NODIR 0x00000001
/*
* 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,
uint32_t flags, int lvblen);
/*
* 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));
/*
* 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__ */
