internal.h

linux 内核源代码

/* internal AFS stuff
 *
 * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([e-mail])
 *
 * 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/fs.h>
#include <linux/pagemap.h>
#include <linux/skbuff.h>
#include <linux/rxrpc.h>
#include <linux/key.h>
#include <linux/workqueue.h>
#include <linux/sched.h>

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

#define AFS_CELL_MAX_ADDRS 15

struct pagevec;
struct afs_call;

typedef enum {
	AFS_VL_NEW,			/* new, uninitialised record */
	AFS_VL_CREATING,		/* creating record */
	AFS_VL_VALID,			/* record is pending */
	AFS_VL_NO_VOLUME,		/* no such volume available */
	AFS_VL_UPDATING,		/* update in progress */
	AFS_VL_VOLUME_DELETED,		/* volume was deleted */
	AFS_VL_UNCERTAIN,		/* uncertain state (update failed) */
} __attribute__((packed)) afs_vlocation_state_t;

struct afs_mount_params {
	bool			rwpath;		/* T if the parent should be considered R/W */
	bool			force;		/* T to force cell type */
	afs_voltype_t		type;		/* type of volume requested */
	int			volnamesz;	/* size of volume name */
	const char		*volname;	/* name of volume to mount */
	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 */
};

/*
 * definition of how to wait for the completion of an operation
 */
struct afs_wait_mode {
	/* RxRPC received message notification */
	void (*rx_wakeup)(struct afs_call *call);

	/* synchronous call waiter and call dispatched notification */
	int (*wait)(struct afs_call *call);

	/* asynchronous call completion */
	void (*async_complete)(void *reply, int error);
};

extern const struct afs_wait_mode afs_sync_call;
extern const struct afs_wait_mode afs_async_call;

/*
 * a record of an in-progress RxRPC call
 */
struct afs_call {
	const struct afs_call_type *type;	/* type of call */
	const struct afs_wait_mode *wait_mode;	/* completion wait mode */
	wait_queue_head_t	waitq;		/* processes awaiting completion */
	struct work_struct	async_work;	/* asynchronous work processor */
	struct work_struct	work;		/* actual work processor */
	struct sk_buff_head	rx_queue;	/* received packets */
	struct rxrpc_call	*rxcall;	/* RxRPC call handle */
	struct key		*key;		/* security for this call */
	struct afs_server	*server;	/* server affected by incoming CM call */
	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;		/* reply buffer (first part) */
	void			*reply2;	/* reply buffer (second part) */
	void			*reply3;	/* reply buffer (third part) */
	void			*reply4;	/* reply buffer (fourth part) */
	pgoff_t			first;		/* first page in mapping to deal with */
	pgoff_t			last;		/* last page in mapping to deal with */
	enum {					/* 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,	/* successfully completed */
		AFS_CALL_BUSY,		/* server was busy */
		AFS_CALL_ABORTED,	/* call was aborted */
		AFS_CALL_ERROR,		/* call failed due to error */
	}			state;
	int			error;		/* error code */
	unsigned		request_size;	/* size of request data */
	unsigned		reply_max;	/* maximum size of reply */
	unsigned		reply_size;	/* current size of reply */
	unsigned		first_offset;	/* offset into mapping[first] */
	unsigned		last_to;	/* amount of mapping[last] */
	unsigned short		offset;		/* offset into received data store */
	unsigned char		unmarshall;	/* unmarshalling phase */
	bool			incoming;	/* T if incoming call */
	bool			send_pages;	/* T if data from mapping should be sent */
	u16			service_id;	/* RxRPC service ID to call */
	__be16			port;		/* target UDP port */
	__be32			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;

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

	/* map an abort code to an error number */
	int (*abort_to_error)(u32 abort_code);

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

/*
 * 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 {
	struct afs_volume	*volume;	/* volume record */
	char			rwparent;	/* T if parent is R/W AFS volume */
};

static inline struct afs_super_info *AFS_FS_S(struct super_block *sb)
{
	return sb->s_fs_info;
}

extern struct file_system_type afs_fs_type;

/*
 * entry in the cached cell catalogue
 */
struct afs_cache_cell {
	char		name[AFS_MAXCELLNAME];	/* cell name (padded with NULs) */
	struct in_addr	vl_servers[15];		/* cached cell VL servers */
};

/*
 * AFS cell record
 */
struct afs_cell {
	atomic_t		usage;
	struct list_head	link;		/* main cell list link */
	struct key		*anonymous_key;	/* anonymous user key for this cell */
	struct list_head	proc_link;	/* /proc cell list link */
	struct proc_dir_entry	*proc_dir;	/* /proc dir for this cell */
#ifdef AFS_CACHING_SUPPORT
	struct cachefs_cookie	*cache;		/* caching cookie */
#endif

	/* server record management */
	rwlock_t		servers_lock;	/* active server list lock */
	struct list_head	servers;	/* active server list */

	/* volume location record management */
	struct rw_semaphore	vl_sem;		/* volume management serialisation semaphore */
	struct list_head	vl_list;	/* cell's active VL record list */
	spinlock_t		vl_lock;	/* vl_list lock */
	unsigned short		vl_naddrs;	/* number of VL servers in addr list */
	unsigned short		vl_curr_svix;	/* current server index */
	struct in_addr		vl_addrs[AFS_CELL_MAX_ADDRS];	/* cell VL server addresses */

	char			name[0];	/* cell name - must go last */
};

/*
 * entry in the cached volume location catalogue
 */
struct afs_cache_vlocation {
	/* volume name (lowercase, padded with NULs) */
	uint8_t			name[AFS_MAXVOLNAME + 1];

	uint8_t			nservers;	/* number of entries used in servers[] */
	uint8_t			vidmask;	/* voltype mask for vid[] */
	uint8_t			srvtmask[8];	/* voltype masks for servers[] */
#define AFS_VOL_VTM_RW	0x01 /* R/W version of the volume is available (on this server) */
#define AFS_VOL_VTM_RO	0x02 /* R/O version of the volume is available (on this server) */
#define AFS_VOL_VTM_BAK	0x04 /* backup version of the volume is available (on this server) */

	afs_volid_t		vid[3];		/* volume IDs for R/W, R/O and Bak volumes */
	struct in_addr		servers[8];	/* fileserver addresses */
	time_t			rtime;		/* last retrieval time */
};

/*
 * volume -> vnode hash table entry
 */
struct afs_cache_vhash {
	afs_voltype_t		vtype;		/* which volume variation */
	uint8_t			hash_bucket;	/* which hash bucket this represents */
} __attribute__((packed));

/*
 * AFS volume location record
 */
struct afs_vlocation {
	atomic_t		usage;
	time_t			time_of_death;	/* time at which put reduced usage to 0 */
	struct list_head	link;		/* link in cell volume location list */
	struct list_head	grave;		/* link in master graveyard list */
	struct list_head	update;		/* link in master update list */
	struct afs_cell		*cell;		/* cell to which volume belongs */
#ifdef AFS_CACHING_SUPPORT
	struct cachefs_cookie	*cache;		/* caching cookie */
#endif
	struct afs_cache_vlocation vldb;	/* volume information DB record */
	struct afs_volume	*vols[3];	/* volume access record pointer (index by type) */
	wait_queue_head_t	waitq;		/* status change waitqueue */
	time_t			update_at;	/* time at which record should be updated */
	spinlock_t		lock;		/* access lock */
	afs_vlocation_state_t	state;		/* volume location state */
	unsigned short		upd_rej_cnt;	/* ENOMEDIUM count during update */
	unsigned short		upd_busy_cnt;	/* EBUSY count during update */
	bool			valid;		/* T if valid */
};

/*
 * AFS fileserver record
 */
struct afs_server {
	atomic_t		usage;
	time_t			time_of_death;	/* time at which put reduced usage to 0 */
	struct in_addr		addr;		/* server address */
	struct afs_cell		*cell;		/* cell in which server resides */
	struct list_head	link;		/* link in cell's server list */
	struct list_head	grave;		/* link in master graveyard list */
	struct rb_node		master_rb;	/* link in master by-addr tree */
	struct rw_semaphore	sem;		/* access lock */

	/* file service access */
	struct rb_root		fs_vnodes;	/* vnodes backed by this server (ordered by FID) */
	unsigned long		fs_act_jif;	/* time at which last activity occurred */
	unsigned long		fs_dead_jif;	/* time at which no longer to be considered dead */
	spinlock_t		fs_lock;	/* access lock */
	int			fs_state;      	/* 0 or reason FS currently marked dead (-errno) */

	/* callback promise management */
	struct rb_root		cb_promises;	/* vnode expiration list (ordered earliest first) */
	struct delayed_work	cb_updater;	/* callback updater */
	struct delayed_work	cb_break_work;	/* collected break dispatcher */
	wait_queue_head_t	cb_break_waitq;	/* space available in cb_break waitqueue */
	spinlock_t		cb_lock;	/* access lock */
	struct afs_callback	cb_break[64];	/* ring of callbacks awaiting breaking */
	atomic_t		cb_break_n;	/* number of pending breaks */
	u8			cb_break_head;	/* head of callback breaking ring */
	u8			cb_break_tail;	/* tail of callback breaking ring */
};