276 lines
8.1 KiB
C
276 lines
8.1 KiB
C
/* -*- mode: c; c-basic-offset: 8; -*-
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* vim: noexpandtab sw=8 ts=8 sts=0:
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*
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* stackglue.h
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*
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* Glue to the underlying cluster stack.
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*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#ifndef STACKGLUE_H
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#define STACKGLUE_H
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#include <linux/types.h>
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#include <linux/list.h>
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#include <linux/dlmconstants.h>
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#include "dlm/dlmapi.h"
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#include <linux/dlm.h>
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/* Needed for plock-related prototypes */
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struct file;
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struct file_lock;
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/*
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* dlmconstants.h does not have a LOCAL flag. We hope to remove it
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* some day, but right now we need it. Let's fake it. This value is larger
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* than any flag in dlmconstants.h.
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*/
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#define DLM_LKF_LOCAL 0x00100000
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/*
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* This shadows DLM_LOCKSPACE_LEN in fs/dlm/dlm_internal.h. That probably
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* wants to be in a public header.
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*/
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#define GROUP_NAME_MAX 64
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/*
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* ocfs2_protocol_version changes when ocfs2 does something different in
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* its inter-node behavior. See dlmglue.c for more information.
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*/
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struct ocfs2_protocol_version {
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u8 pv_major;
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u8 pv_minor;
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};
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/*
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* The ocfs2_locking_protocol defines the handlers called on ocfs2's behalf.
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*/
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struct ocfs2_locking_protocol {
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struct ocfs2_protocol_version lp_max_version;
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void (*lp_lock_ast)(void *astarg);
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void (*lp_blocking_ast)(void *astarg, int level);
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void (*lp_unlock_ast)(void *astarg, int error);
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};
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/*
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* The dlm_lockstatus struct includes lvb space, but the dlm_lksb struct only
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* has a pointer to separately allocated lvb space. This struct exists only to
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* include in the lksb union to make space for a combined dlm_lksb and lvb.
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*/
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struct fsdlm_lksb_plus_lvb {
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struct dlm_lksb lksb;
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char lvb[DLM_LVB_LEN];
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};
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/*
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* A union of all lock status structures. We define it here so that the
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* size of the union is known. Lock status structures are embedded in
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* ocfs2 inodes.
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*/
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union ocfs2_dlm_lksb {
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struct dlm_lockstatus lksb_o2dlm;
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struct dlm_lksb lksb_fsdlm;
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struct fsdlm_lksb_plus_lvb padding;
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};
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/*
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* A cluster connection. Mostly opaque to ocfs2, the connection holds
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* state for the underlying stack. ocfs2 does use cc_version to determine
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* locking compatibility.
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*/
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struct ocfs2_cluster_connection {
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char cc_name[GROUP_NAME_MAX];
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int cc_namelen;
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struct ocfs2_protocol_version cc_version;
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void (*cc_recovery_handler)(int node_num, void *recovery_data);
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void *cc_recovery_data;
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void *cc_lockspace;
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void *cc_private;
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};
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/*
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* Each cluster stack implements the stack operations structure. Not used
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* in the ocfs2 code, the stackglue code translates generic cluster calls
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* into stack operations.
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*/
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struct ocfs2_stack_operations {
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/*
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* The fs code calls ocfs2_cluster_connect() to attach a new
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* filesystem to the cluster stack. The ->connect() op is passed
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* an ocfs2_cluster_connection with the name and recovery field
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* filled in.
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*
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* The stack must set up any notification mechanisms and create
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* the filesystem lockspace in the DLM. The lockspace should be
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* stored on cc_lockspace. Any other information can be stored on
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* cc_private.
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*
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* ->connect() must not return until it is guaranteed that
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*
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* - Node down notifications for the filesystem will be recieved
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* and passed to conn->cc_recovery_handler().
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* - Locking requests for the filesystem will be processed.
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*/
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int (*connect)(struct ocfs2_cluster_connection *conn);
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/*
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* The fs code calls ocfs2_cluster_disconnect() when a filesystem
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* no longer needs cluster services. All DLM locks have been
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* dropped, and recovery notification is being ignored by the
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* fs code. The stack must disengage from the DLM and discontinue
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* recovery notification.
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*
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* Once ->disconnect() has returned, the connection structure will
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* be freed. Thus, a stack must not return from ->disconnect()
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* until it will no longer reference the conn pointer.
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*
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* Once this call returns, the stack glue will be dropping this
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* connection's reference on the module.
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*/
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int (*disconnect)(struct ocfs2_cluster_connection *conn);
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/*
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* ->this_node() returns the cluster's unique identifier for the
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* local node.
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*/
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int (*this_node)(unsigned int *node);
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/*
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* Call the underlying dlm lock function. The ->dlm_lock()
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* callback should convert the flags and mode as appropriate.
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*
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* ast and bast functions are not part of the call because the
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* stack will likely want to wrap ast and bast calls before passing
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* them to stack->sp_proto.
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*/
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int (*dlm_lock)(struct ocfs2_cluster_connection *conn,
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int mode,
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union ocfs2_dlm_lksb *lksb,
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u32 flags,
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void *name,
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unsigned int namelen,
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void *astarg);
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/*
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* Call the underlying dlm unlock function. The ->dlm_unlock()
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* function should convert the flags as appropriate.
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*
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* The unlock ast is not passed, as the stack will want to wrap
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* it before calling stack->sp_proto->lp_unlock_ast().
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*/
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int (*dlm_unlock)(struct ocfs2_cluster_connection *conn,
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union ocfs2_dlm_lksb *lksb,
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u32 flags,
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void *astarg);
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/*
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* Return the status of the current lock status block. The fs
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* code should never dereference the union. The ->lock_status()
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* callback pulls out the stack-specific lksb, converts the status
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* to a proper errno, and returns it.
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*/
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int (*lock_status)(union ocfs2_dlm_lksb *lksb);
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/*
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* Return non-zero if the LVB is valid.
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*/
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int (*lvb_valid)(union ocfs2_dlm_lksb *lksb);
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/*
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* Pull the lvb pointer off of the stack-specific lksb.
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*/
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void *(*lock_lvb)(union ocfs2_dlm_lksb *lksb);
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/*
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* Cluster-aware posix locks
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*
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* This is NULL for stacks which do not support posix locks.
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*/
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int (*plock)(struct ocfs2_cluster_connection *conn,
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u64 ino,
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struct file *file,
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int cmd,
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struct file_lock *fl);
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/*
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* This is an optoinal debugging hook. If provided, the
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* stack can dump debugging information about this lock.
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*/
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void (*dump_lksb)(union ocfs2_dlm_lksb *lksb);
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};
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/*
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* Each stack plugin must describe itself by registering a
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* ocfs2_stack_plugin structure. This is only seen by stackglue and the
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* stack driver.
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*/
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struct ocfs2_stack_plugin {
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char *sp_name;
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struct ocfs2_stack_operations *sp_ops;
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struct module *sp_owner;
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/* These are managed by the stackglue code. */
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struct list_head sp_list;
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unsigned int sp_count;
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struct ocfs2_locking_protocol *sp_proto;
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};
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/* Used by the filesystem */
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int ocfs2_cluster_connect(const char *stack_name,
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const char *group,
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int grouplen,
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void (*recovery_handler)(int node_num,
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void *recovery_data),
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void *recovery_data,
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struct ocfs2_cluster_connection **conn);
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int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
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int hangup_pending);
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void ocfs2_cluster_hangup(const char *group, int grouplen);
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int ocfs2_cluster_this_node(unsigned int *node);
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struct ocfs2_lock_res;
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int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
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int mode,
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union ocfs2_dlm_lksb *lksb,
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u32 flags,
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void *name,
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unsigned int namelen,
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struct ocfs2_lock_res *astarg);
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int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
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union ocfs2_dlm_lksb *lksb,
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u32 flags,
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struct ocfs2_lock_res *astarg);
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int ocfs2_dlm_lock_status(union ocfs2_dlm_lksb *lksb);
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int ocfs2_dlm_lvb_valid(union ocfs2_dlm_lksb *lksb);
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void *ocfs2_dlm_lvb(union ocfs2_dlm_lksb *lksb);
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void ocfs2_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb);
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int ocfs2_stack_supports_plocks(void);
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int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
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struct file *file, int cmd, struct file_lock *fl);
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void ocfs2_stack_glue_set_locking_protocol(struct ocfs2_locking_protocol *proto);
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/* Used by stack plugins */
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int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin);
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void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin);
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#endif /* STACKGLUE_H */
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