[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>
This commit is contained in:
David Teigland
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Steven Whitehouse
Steven Whitehouse
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e473142070
commit
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312
include/linux/dlm.h
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312
include/linux/dlm.h
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/******************************************************************************
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*******************************************************************************
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**
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** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
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** Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
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**
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** This copyrighted material is made available to anyone wishing to use,
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** modify, copy, or redistribute it subject to the terms and conditions
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** of the GNU General Public License v.2.
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**
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*******************************************************************************
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******************************************************************************/
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#ifndef __DLM_DOT_H__
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#define __DLM_DOT_H__
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/*
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* Interface to Distributed Lock Manager (DLM)
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* routines and structures to use DLM lockspaces
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*/
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/*
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* Lock Modes
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*/
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#define DLM_LOCK_IV -1 /* invalid */
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#define DLM_LOCK_NL 0 /* null */
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#define DLM_LOCK_CR 1 /* concurrent read */
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#define DLM_LOCK_CW 2 /* concurrent write */
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#define DLM_LOCK_PR 3 /* protected read */
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#define DLM_LOCK_PW 4 /* protected write */
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#define DLM_LOCK_EX 5 /* exclusive */
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/*
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* Maximum size in bytes of a dlm_lock name
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*/
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#define DLM_RESNAME_MAXLEN 64
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/*
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* Flags to dlm_lock
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*
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* DLM_LKF_NOQUEUE
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*
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* Do not queue the lock request on the wait queue if it cannot be granted
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* immediately. If the lock cannot be granted because of this flag, DLM will
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* either return -EAGAIN from the dlm_lock call or will return 0 from
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* dlm_lock and -EAGAIN in the lock status block when the AST is executed.
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*
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* DLM_LKF_CANCEL
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*
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* Used to cancel a pending lock request or conversion. A converting lock is
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* returned to its previously granted mode.
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*
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* DLM_LKF_CONVERT
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*
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* Indicates a lock conversion request. For conversions the name and namelen
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* are ignored and the lock ID in the LKSB is used to identify the lock.
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*
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* DLM_LKF_VALBLK
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*
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* Requests DLM to return the current contents of the lock value block in the
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* lock status block. When this flag is set in a lock conversion from PW or EX
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* modes, DLM assigns the value specified in the lock status block to the lock
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* value block of the lock resource. The LVB is a DLM_LVB_LEN size array
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* containing application-specific information.
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*
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* DLM_LKF_QUECVT
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*
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* Force a conversion request to be queued, even if it is compatible with
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* the granted modes of other locks on the same resource.
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*
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* DLM_LKF_IVVALBLK
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*
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* Invalidate the lock value block.
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*
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* DLM_LKF_CONVDEADLK
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*
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* Allows the dlm to resolve conversion deadlocks internally by demoting the
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* granted mode of a converting lock to NL. The DLM_SBF_DEMOTED flag is
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* returned for a conversion that's been effected by this.
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*
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* DLM_LKF_PERSISTENT
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*
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* Only relevant to locks originating in userspace. A persistent lock will not
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* be removed if the process holding the lock exits.
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*
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* DLM_LKF_NODLKWT
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* DLM_LKF_NODLCKBLK
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*
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* net yet implemented
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*
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* DLM_LKF_EXPEDITE
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*
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* Used only with new requests for NL mode locks. Tells the lock manager
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* to grant the lock, ignoring other locks in convert and wait queues.
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*
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* DLM_LKF_NOQUEUEBAST
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*
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* Send blocking AST's before returning -EAGAIN to the caller. It is only
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* used along with the NOQUEUE flag. Blocking AST's are not sent for failed
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* NOQUEUE requests otherwise.
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*
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* DLM_LKF_HEADQUE
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*
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* Add a lock to the head of the convert or wait queue rather than the tail.
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*
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* DLM_LKF_NOORDER
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*
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* Disregard the standard grant order rules and grant a lock as soon as it
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* is compatible with other granted locks.
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*
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* DLM_LKF_ORPHAN
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*
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* not yet implemented
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*
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* DLM_LKF_ALTPR
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*
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* If the requested mode cannot be granted immediately, try to grant the lock
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* in PR mode instead. If this alternate mode is granted instead of the
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* requested mode, DLM_SBF_ALTMODE is returned in the lksb.
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*
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* DLM_LKF_ALTCW
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*
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* The same as ALTPR, but the alternate mode is CW.
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*
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* DLM_LKF_FORCEUNLOCK
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*
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* Unlock the lock even if it is converting or waiting or has sublocks.
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* Only really for use by the userland device.c code.
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*
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*/
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#define DLM_LKF_NOQUEUE 0x00000001
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#define DLM_LKF_CANCEL 0x00000002
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#define DLM_LKF_CONVERT 0x00000004
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#define DLM_LKF_VALBLK 0x00000008
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#define DLM_LKF_QUECVT 0x00000010
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#define DLM_LKF_IVVALBLK 0x00000020
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#define DLM_LKF_CONVDEADLK 0x00000040
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#define DLM_LKF_PERSISTENT 0x00000080
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#define DLM_LKF_NODLCKWT 0x00000100
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#define DLM_LKF_NODLCKBLK 0x00000200
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#define DLM_LKF_EXPEDITE 0x00000400
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#define DLM_LKF_NOQUEUEBAST 0x00000800
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#define DLM_LKF_HEADQUE 0x00001000
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#define DLM_LKF_NOORDER 0x00002000
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#define DLM_LKF_ORPHAN 0x00004000
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#define DLM_LKF_ALTPR 0x00008000
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#define DLM_LKF_ALTCW 0x00010000
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#define DLM_LKF_FORCEUNLOCK 0x00020000
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/*
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* Some return codes that are not in errno.h
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*/
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#define DLM_ECANCEL 0x10001
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#define DLM_EUNLOCK 0x10002
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typedef void dlm_lockspace_t;
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/*
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* Lock range structure
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*/
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struct dlm_range {
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uint64_t ra_start;
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uint64_t ra_end;
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};
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/*
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* Lock status block
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*
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* Use this structure to specify the contents of the lock value block. For a
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* conversion request, this structure is used to specify the lock ID of the
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* lock. DLM writes the status of the lock request and the lock ID assigned
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* to the request in the lock status block.
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*
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* sb_lkid: the returned lock ID. It is set on new (non-conversion) requests.
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* It is available when dlm_lock returns.
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*
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* sb_lvbptr: saves or returns the contents of the lock's LVB according to rules
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* shown for the DLM_LKF_VALBLK flag.
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*
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* sb_flags: DLM_SBF_DEMOTED is returned if in the process of promoting a lock,
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* it was first demoted to NL to avoid conversion deadlock.
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* DLM_SBF_VALNOTVALID is returned if the resource's LVB is marked invalid.
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*
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* sb_status: the returned status of the lock request set prior to AST
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* execution. Possible return values:
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*
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* 0 if lock request was successful
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* -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
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* -ENOMEM if there is no memory to process request
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* -EINVAL if there are invalid parameters
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* -DLM_EUNLOCK if unlock request was successful
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* -DLM_ECANCEL if a cancel completed successfully
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*/
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#define DLM_SBF_DEMOTED 0x01
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#define DLM_SBF_VALNOTVALID 0x02
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#define DLM_SBF_ALTMODE 0x04
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struct dlm_lksb {
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int sb_status;
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uint32_t sb_lkid;
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char sb_flags;
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char * sb_lvbptr;
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};
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#ifdef __KERNEL__
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#define DLM_LSFL_NODIR 0x00000001
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/*
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* dlm_new_lockspace
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*
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* Starts a lockspace with the given name. If the named lockspace exists in
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* the cluster, the calling node joins it.
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*/
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int dlm_new_lockspace(char *name, int namelen, dlm_lockspace_t **lockspace,
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uint32_t flags, int lvblen);
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/*
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* dlm_release_lockspace
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*
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* Stop a lockspace.
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*/
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int dlm_release_lockspace(dlm_lockspace_t *lockspace, int force);
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/*
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* dlm_lock
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*
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* Make an asyncronous request to acquire or convert a lock on a named
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* resource.
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*
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* lockspace: context for the request
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* mode: the requested mode of the lock (DLM_LOCK_)
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* lksb: lock status block for input and async return values
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* flags: input flags (DLM_LKF_)
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* name: name of the resource to lock, can be binary
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* namelen: the length in bytes of the resource name (MAX_RESNAME_LEN)
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* parent: the lock ID of a parent lock or 0 if none
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* lockast: function DLM executes when it completes processing the request
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* astarg: argument passed to lockast and bast functions
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* bast: function DLM executes when this lock later blocks another request
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*
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* Returns:
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* 0 if request is successfully queued for processing
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* -EINVAL if any input parameters are invalid
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* -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
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* -ENOMEM if there is no memory to process request
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* -ENOTCONN if there is a communication error
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*
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* If the call to dlm_lock returns an error then the operation has failed and
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* the AST routine will not be called. If dlm_lock returns 0 it is still
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* possible that the lock operation will fail. The AST routine will be called
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* when the locking is complete and the status is returned in the lksb.
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*
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* If the AST routines or parameter are passed to a conversion operation then
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* they will overwrite those values that were passed to a previous dlm_lock
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* call.
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*
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* AST routines should not block (at least not for long), but may make
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* any locking calls they please.
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*/
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int dlm_lock(dlm_lockspace_t *lockspace,
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int mode,
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struct dlm_lksb *lksb,
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uint32_t flags,
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void *name,
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unsigned int namelen,
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uint32_t parent_lkid,
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void (*lockast) (void *astarg),
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void *astarg,
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void (*bast) (void *astarg, int mode),
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struct dlm_range *range);
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/*
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* dlm_unlock
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*
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* Asynchronously release a lock on a resource. The AST routine is called
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* when the resource is successfully unlocked.
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*
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* lockspace: context for the request
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* lkid: the lock ID as returned in the lksb
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* flags: input flags (DLM_LKF_)
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* lksb: if NULL the lksb parameter passed to last lock request is used
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* astarg: the arg used with the completion ast for the unlock
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*
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* Returns:
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* 0 if request is successfully queued for processing
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* -EINVAL if any input parameters are invalid
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* -ENOTEMPTY if the lock still has sublocks
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* -EBUSY if the lock is waiting for a remote lock operation
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* -ENOTCONN if there is a communication error
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*/
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int dlm_unlock(dlm_lockspace_t *lockspace,
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uint32_t lkid,
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uint32_t flags,
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struct dlm_lksb *lksb,
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void *astarg);
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#endif /* __KERNEL__ */
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#endif /* __DLM_DOT_H__ */
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