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