![Jonthan Brassow](/assets/img/avatar_default.png)
This patch contains a device-mapper mirror log module that forwards requests to userspace for processing. The structures used for communication between kernel and userspace are located in include/linux/dm-log-userspace.h. Due to the frequency, diversity, and 2-way communication nature of the exchanges between kernel and userspace, 'connector' was chosen as the interface for communication. The first log implementations written in userspace - "clustered-disk" and "clustered-core" - support clustered shared storage. A userspace daemon (in the LVM2 source code repository) uses openAIS/corosync to process requests in an ordered fashion with the rest of the nodes in the cluster so as to prevent log state corruption. Other implementations with no association to LVM or openAIS/corosync, are certainly possible. (Imagine if two machines are writing to the same region of a mirror. They would both mark the region dirty, but you need a cluster-aware entity that can handle properly marking the region clean when they are done. Otherwise, you might clear the region when the first machine is done, not the second.) Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
188 lines
4.3 KiB
C
188 lines
4.3 KiB
C
/*
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* connector.h
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*
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* 2004-2005 Copyright (c) Evgeniy Polyakov <johnpol@2ka.mipt.ru>
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef __CONNECTOR_H
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#define __CONNECTOR_H
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#include <linux/types.h>
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#define CN_IDX_CONNECTOR 0xffffffff
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#define CN_VAL_CONNECTOR 0xffffffff
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/*
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* Process Events connector unique ids -- used for message routing
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*/
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#define CN_IDX_PROC 0x1
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#define CN_VAL_PROC 0x1
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#define CN_IDX_CIFS 0x2
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#define CN_VAL_CIFS 0x1
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#define CN_W1_IDX 0x3 /* w1 communication */
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#define CN_W1_VAL 0x1
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#define CN_IDX_V86D 0x4
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#define CN_VAL_V86D_UVESAFB 0x1
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#define CN_IDX_BB 0x5 /* BlackBoard, from the TSP GPL sampling framework */
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#define CN_DST_IDX 0x6
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#define CN_DST_VAL 0x1
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#define CN_IDX_DM 0x7 /* Device Mapper */
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#define CN_VAL_DM_USERSPACE_LOG 0x1
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#define CN_NETLINK_USERS 8
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/*
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* Maximum connector's message size.
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*/
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#define CONNECTOR_MAX_MSG_SIZE 16384
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/*
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* idx and val are unique identifiers which
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* are used for message routing and
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* must be registered in connector.h for in-kernel usage.
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*/
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struct cb_id {
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__u32 idx;
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__u32 val;
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};
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struct cn_msg {
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struct cb_id id;
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__u32 seq;
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__u32 ack;
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__u16 len; /* Length of the following data */
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__u16 flags;
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__u8 data[0];
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};
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/*
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* Notify structure - requests notification about
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* registering/unregistering idx/val in range [first, first+range].
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*/
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struct cn_notify_req {
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__u32 first;
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__u32 range;
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};
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/*
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* Main notification control message
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* *_notify_num - number of appropriate cn_notify_req structures after
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* this struct.
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* group - notification receiver's idx.
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* len - total length of the attached data.
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*/
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struct cn_ctl_msg {
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__u32 idx_notify_num;
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__u32 val_notify_num;
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__u32 group;
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__u32 len;
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__u8 data[0];
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};
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#ifdef __KERNEL__
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#include <asm/atomic.h>
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#include <linux/list.h>
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#include <linux/workqueue.h>
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#include <net/sock.h>
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#define CN_CBQ_NAMELEN 32
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struct cn_queue_dev {
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atomic_t refcnt;
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unsigned char name[CN_CBQ_NAMELEN];
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struct workqueue_struct *cn_queue;
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/* Sent to kevent to create cn_queue only when needed */
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struct work_struct wq_creation;
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/* Tell if the wq_creation job is pending/completed */
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atomic_t wq_requested;
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/* Wait for cn_queue to be created */
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wait_queue_head_t wq_created;
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struct list_head queue_list;
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spinlock_t queue_lock;
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struct sock *nls;
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};
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struct cn_callback_id {
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unsigned char name[CN_CBQ_NAMELEN];
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struct cb_id id;
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};
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struct cn_callback_data {
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void (*destruct_data) (void *);
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void *ddata;
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void *callback_priv;
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void (*callback) (void *);
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void *free;
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};
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struct cn_callback_entry {
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struct list_head callback_entry;
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struct work_struct work;
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struct cn_queue_dev *pdev;
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struct cn_callback_id id;
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struct cn_callback_data data;
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u32 seq, group;
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};
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struct cn_ctl_entry {
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struct list_head notify_entry;
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struct cn_ctl_msg *msg;
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};
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struct cn_dev {
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struct cb_id id;
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u32 seq, groups;
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struct sock *nls;
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void (*input) (struct sk_buff *skb);
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struct cn_queue_dev *cbdev;
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};
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int cn_add_callback(struct cb_id *, char *, void (*callback) (void *));
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void cn_del_callback(struct cb_id *);
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int cn_netlink_send(struct cn_msg *, u32, gfp_t);
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int cn_queue_add_callback(struct cn_queue_dev *dev, char *name, struct cb_id *id, void (*callback)(void *));
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void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id);
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int queue_cn_work(struct cn_callback_entry *cbq, struct work_struct *work);
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struct cn_queue_dev *cn_queue_alloc_dev(char *name, struct sock *);
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void cn_queue_free_dev(struct cn_queue_dev *dev);
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int cn_cb_equal(struct cb_id *, struct cb_id *);
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void cn_queue_wrapper(struct work_struct *work);
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#endif /* __KERNEL__ */
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#endif /* __CONNECTOR_H */
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