internal.h

/* internal AFS stuff
 *
 * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * 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; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/compiler.h>
#include <linux/kernel.h>
#include <linux/ktime.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/rxrpc.h>
#include <linux/key.h>
#include <linux/workqueue.h>
#include <linux/sched.h>
#include <linux/fscache.h>
#include <linux/backing-dev.h>
#include <linux/uuid.h>
#include <net/net_namespace.h>
#include <net/af_rxrpc.h>

#include "afs.h"
#include "afs_vl.h"

#define AFS_CELL_MAX_ADDRS 15

struct pagevec;
struct afs_call;

struct afs_mount_params {
	bool			rwpath;		/* T if the parent should be considered R/W */
	bool			force;		/* T to force cell type */
	bool			autocell;	/* T if set auto mount operation */
	afs_voltype_t		type;		/* type of volume requested */
	int			volnamesz;	/* size of volume name */
	const char		*volname;	/* name of volume to mount */
	struct afs_net		*net;		/* Network namespace in effect */
	struct afs_cell		*cell;		/* cell in which to find volume */
	struct afs_volume	*volume;	/* volume record */
	struct key		*key;		/* key to use for secure mounting */
};

struct afs_iget_data {
	struct afs_fid		fid;
	struct afs_volume	*volume;	/* volume on which resides */
};

enum afs_call_state {
	AFS_CALL_REQUESTING,	/* request is being sent for outgoing call */
	AFS_CALL_AWAIT_REPLY,	/* awaiting reply to outgoing call */
	AFS_CALL_AWAIT_OP_ID,	/* awaiting op ID on incoming call */
	AFS_CALL_AWAIT_REQUEST,	/* awaiting request data on incoming call */
	AFS_CALL_REPLYING,	/* replying to incoming call */
	AFS_CALL_AWAIT_ACK,	/* awaiting final ACK of incoming call */
	AFS_CALL_COMPLETE,	/* Completed or failed */
};

/*
 * List of server addresses.
 */
struct afs_addr_list {
	struct rcu_head		rcu;		/* Must be first */
	refcount_t		usage;
	u32			version;	/* Version */
	unsigned short		nr_addrs;
	unsigned short		index;		/* Address currently in use */
	unsigned short		nr_ipv4;	/* Number of IPv4 addresses */
	unsigned long		probed;		/* Mask of servers that have been probed */
	unsigned long		yfs;		/* Mask of servers that are YFS */
	struct sockaddr_rxrpc	addrs[];
};

/*
 * a record of an in-progress RxRPC call
 */
struct afs_call {
	const struct afs_call_type *type;	/* type of call */
	wait_queue_head_t	waitq;		/* processes awaiting completion */
	struct work_struct	async_work;	/* async I/O processor */
	struct work_struct	work;		/* actual work processor */
	struct rxrpc_call	*rxcall;	/* RxRPC call handle */
	struct key		*key;		/* security for this call */
	struct afs_net		*net;		/* The network namespace */
	struct afs_server	*cm_server;	/* Server affected by incoming CM call */
	struct afs_cb_interest	*cbi;		/* Callback interest for server used */
	void			*request;	/* request data (first part) */
	struct address_space	*mapping;	/* page set */
	struct afs_writeback	*wb;		/* writeback being performed */
	void			*buffer;	/* reply receive buffer */
	void			*reply[4];	/* Where to put the reply */
	pgoff_t			first;		/* first page in mapping to deal with */
	pgoff_t			last;		/* last page in mapping to deal with */
	size_t			offset;		/* offset into received data store */
	atomic_t		usage;
	enum afs_call_state	state;
	int			error;		/* error code */
	u32			abort_code;	/* Remote abort ID or 0 */
	unsigned		request_size;	/* size of request data */
	unsigned		reply_max;	/* maximum size of reply */
	unsigned		first_offset;	/* offset into mapping[first] */
	unsigned int		cb_break;	/* cb_break + cb_s_break before the call */
	union {
		unsigned	last_to;	/* amount of mapping[last] */
		unsigned	count2;		/* count used in unmarshalling */
	};
	unsigned char		unmarshall;	/* unmarshalling phase */
	bool			incoming;	/* T if incoming call */
	bool			send_pages;	/* T if data from mapping should be sent */
	bool			need_attention;	/* T if RxRPC poked us */
	bool			async;		/* T if asynchronous */
	bool			ret_reply0;	/* T if should return reply[0] on success */
	bool			upgrade;	/* T to request service upgrade */
	u16			service_id;	/* Actual service ID (after upgrade) */
	u32			operation_ID;	/* operation ID for an incoming call */
	u32			count;		/* count for use in unmarshalling */
	__be32			tmp;		/* place to extract temporary data */
	afs_dataversion_t	store_version;	/* updated version expected from store */
};

struct afs_call_type {
	const char *name;
	unsigned int op; /* Really enum afs_fs_operation */

	/* deliver request or reply data to an call
	 * - returning an error will cause the call to be aborted
	 */
	int (*deliver)(struct afs_call *call);

	/* clean up a call */
	void (*destructor)(struct afs_call *call);

	/* Work function */
	void (*work)(struct work_struct *work);
};

/*
 * AFS open file information record.  Pointed to by file->private_data.
 */
struct afs_file {
	struct key		*key;		/* The key this file was opened with */
};

static inline struct key *afs_file_key(struct file *file)
{
	struct afs_file *af = file->private_data;

	return af->key;
}

/*
 * Record of an outstanding read operation on a vnode.
 */
struct afs_read {
	loff_t			pos;		/* Where to start reading */
	loff_t			len;		/* How much we're asking for */
	loff_t			actual_len;	/* How much we're actually getting */
	loff_t			remain;		/* Amount remaining */
	atomic_t		usage;
	unsigned int		index;		/* Which page we're reading into */
	unsigned int		nr_pages;
	void (*page_done)(struct afs_call *, struct afs_read *);
	struct page		*pages[];
};

/*
 * record of an outstanding writeback on a vnode
 */
struct afs_writeback {
	struct list_head	link;		/* link in vnode->writebacks */
	struct work_struct	writer;		/* work item to perform the writeback */
	struct afs_vnode	*vnode;		/* vnode to which this write applies */
	struct key		*key;		/* owner of this write */
	wait_queue_head_t	waitq;		/* completion and ready wait queue */
	pgoff_t			first;		/* first page in batch */
	pgoff_t			point;		/* last page in current store op */
	pgoff_t			last;		/* last page in batch (inclusive) */
	unsigned		offset_first;	/* offset into first page of start of write */
	unsigned		to_last;	/* offset into last page of end of write */
	int			num_conflicts;	/* count of conflicting writes in list */
	int			usage;
	bool			conflicts;	/* T if has dependent conflicts */
	enum {
		AFS_WBACK_SYNCING,		/* synchronisation being performed */
		AFS_WBACK_PENDING,		/* write pending */
		AFS_WBACK_CONFLICTING,		/* conflicting writes posted */
		AFS_WBACK_WRITING,		/* writing back */
		AFS_WBACK_COMPLETE		/* the writeback record has been unlinked */
	} state __attribute__((packed));
};

/*
 * AFS superblock private data
 * - there's one superblock per volume
 */
struct afs_super_info {