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Diffstat (limited to 'fs/ocfs2/stackglue.h')
| -rw-r--r-- | fs/ocfs2/stackglue.h | 301 |
1 files changed, 301 insertions, 0 deletions
diff --git a/fs/ocfs2/stackglue.h b/fs/ocfs2/stackglue.h new file mode 100644 index 000000000..66334a30c --- /dev/null +++ b/fs/ocfs2/stackglue.h @@ -0,0 +1,301 @@ +/* -*- 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 + +/* This shadows OCFS2_CLUSTER_NAME_LEN */ +#define CLUSTER_NAME_MAX 16 + + +/* + * 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 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. + */ +struct ocfs2_cluster_connection; +struct ocfs2_dlm_lksb { + union { + struct dlm_lockstatus lksb_o2dlm; + struct dlm_lksb lksb_fsdlm; + struct fsdlm_lksb_plus_lvb padding; + }; + struct ocfs2_cluster_connection *lksb_conn; +}; + +/* + * 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)(struct ocfs2_dlm_lksb *lksb); + void (*lp_blocking_ast)(struct ocfs2_dlm_lksb *lksb, int level); + void (*lp_unlock_ast)(struct ocfs2_dlm_lksb *lksb, int error); +}; + + +/* + * 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 + 1]; + int cc_namelen; + char cc_cluster_name[CLUSTER_NAME_MAX + 1]; + int cc_cluster_name_len; + struct ocfs2_protocol_version cc_version; + struct ocfs2_locking_protocol *cc_proto; + 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 received + * 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)(struct ocfs2_cluster_connection *conn, + 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. There is no astarg. The lksb will + * be passed back to the ast and bast functions. The caller can + * use this to find their object. + */ + int (*dlm_lock)(struct ocfs2_cluster_connection *conn, + int mode, + struct ocfs2_dlm_lksb *lksb, + u32 flags, + void *name, + unsigned int namelen); + + /* + * 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(). There is + * no astarg. The lksb will be passed back to the unlock ast + * function. The caller can use this to find their object. + */ + int (*dlm_unlock)(struct ocfs2_cluster_connection *conn, + struct ocfs2_dlm_lksb *lksb, + u32 flags); + + /* + * 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)(struct ocfs2_dlm_lksb *lksb); + + /* + * Return non-zero if the LVB is valid. + */ + int (*lvb_valid)(struct ocfs2_dlm_lksb *lksb); + + /* + * Pull the lvb pointer off of the stack-specific lksb. + */ + void *(*lock_lvb)(struct 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)(struct 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_protocol_version sp_max_proto; +}; + + +/* Used by the filesystem */ +int ocfs2_cluster_connect(const char *stack_name, + const char *cluster_name, + int cluster_name_len, + const char *group, + int grouplen, + struct ocfs2_locking_protocol *lproto, + void (*recovery_handler)(int node_num, + void *recovery_data), + void *recovery_data, + struct ocfs2_cluster_connection **conn); +/* + * Used by callers that don't store their stack name. They must ensure + * all nodes have the same stack. + */ +int ocfs2_cluster_connect_agnostic(const char *group, + int grouplen, + struct ocfs2_locking_protocol *lproto, + 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(struct ocfs2_cluster_connection *conn, + unsigned int *node); + +struct ocfs2_lock_res; +int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn, + int mode, + struct ocfs2_dlm_lksb *lksb, + u32 flags, + void *name, + unsigned int namelen); +int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn, + struct ocfs2_dlm_lksb *lksb, + u32 flags); + +int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb); +int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb); +void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb); +void ocfs2_dlm_dump_lksb(struct 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_max_proto_version(struct ocfs2_protocol_version *max_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 */ |