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![David Teigland](/assets/img/avatar_default.png)
These new callbacks notify the dlm user about lock recovery. GFS2, and possibly others, need to be aware of when the dlm will be doing lock recovery for a failed lockspace member. In the past, this coordination has been done between dlm and file system daemons in userspace, which then direct their kernel counterparts. These callbacks allow the same coordination directly, and more simply. Signed-off-by: David Teigland <teigland@redhat.com>
233 lines
7.8 KiB
C
233 lines
7.8 KiB
C
/******************************************************************************
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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) 2004-2011 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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/* Lock levels and flags are here */
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#include <linux/dlmconstants.h>
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#include <linux/types.h>
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typedef void dlm_lockspace_t;
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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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* -DLM_EUNLOCK if unlock request was successful
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* -DLM_ECANCEL if a cancel completed successfully
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* -EDEADLK if a deadlock was detected
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* -ETIMEDOUT if the lock request was canceled due to a timeout
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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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__u32 sb_lkid;
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char sb_flags;
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char * sb_lvbptr;
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};
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/* dlm_new_lockspace() flags */
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#define DLM_LSFL_NODIR 0x00000001
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#define DLM_LSFL_TIMEWARN 0x00000002
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#define DLM_LSFL_FS 0x00000004
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#define DLM_LSFL_NEWEXCL 0x00000008
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#ifdef __KERNEL__
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struct dlm_slot {
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int nodeid; /* 1 to MAX_INT */
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int slot; /* 1 to MAX_INT */
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};
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/*
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* recover_prep: called before the dlm begins lock recovery.
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* Notfies lockspace user that locks from failed members will be granted.
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* recover_slot: called after recover_prep and before recover_done.
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* Identifies a failed lockspace member.
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* recover_done: called after the dlm completes lock recovery.
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* Identifies lockspace members and lockspace generation number.
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*/
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struct dlm_lockspace_ops {
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void (*recover_prep) (void *ops_arg);
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void (*recover_slot) (void *ops_arg, struct dlm_slot *slot);
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void (*recover_done) (void *ops_arg, struct dlm_slot *slots,
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int num_slots, int our_slot, uint32_t generation);
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};
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/*
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* dlm_new_lockspace
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*
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* Create/join a lockspace.
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*
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* name: lockspace name, null terminated, up to DLM_LOCKSPACE_LEN (not
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* including terminating null).
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*
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* cluster: cluster name, null terminated, up to DLM_LOCKSPACE_LEN (not
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* including terminating null). Optional. When cluster is null, it
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* is not used. When set, dlm_new_lockspace() returns -EBADR if cluster
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* is not equal to the dlm cluster name.
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*
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* flags:
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* DLM_LSFL_NODIR
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* The dlm should not use a resource directory, but statically assign
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* resource mastery to nodes based on the name hash that is otherwise
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* used to select the directory node. Must be the same on all nodes.
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* DLM_LSFL_TIMEWARN
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* The dlm should emit netlink messages if locks have been waiting
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* for a configurable amount of time. (Unused.)
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* DLM_LSFL_FS
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* The lockspace user is in the kernel (i.e. filesystem). Enables
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* direct bast/cast callbacks.
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* DLM_LSFL_NEWEXCL
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* dlm_new_lockspace() should return -EEXIST if the lockspace exists.
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*
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* lvblen: length of lvb in bytes. Must be multiple of 8.
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* dlm_new_lockspace() returns an error if this does not match
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* what other nodes are using.
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*
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* ops: callbacks that indicate lockspace recovery points so the
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* caller can coordinate its recovery and know lockspace members.
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* This is only used by the initial dlm_new_lockspace() call.
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* Optional.
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*
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* ops_arg: arg for ops callbacks.
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*
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* ops_result: tells caller if the ops callbacks (if provided) will
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* be used or not. 0: will be used, -EXXX will not be used.
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* -EOPNOTSUPP: the dlm does not have recovery_callbacks enabled.
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*
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* lockspace: handle for dlm functions
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*/
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int dlm_new_lockspace(const char *name, const char *cluster,
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uint32_t flags, int lvblen,
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const struct dlm_lockspace_ops *ops, void *ops_arg,
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int *ops_result, dlm_lockspace_t **lockspace);
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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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/*
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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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