1/*
2 * linux/include/linux/nfs_page.h
3 *
4 * Copyright (C) 2000 Trond Myklebust
5 *
6 * NFS page cache wrapper.
7 */
8
9#ifndef _LINUX_NFS_PAGE_H
10#define _LINUX_NFS_PAGE_H
11
12
13#include <linux/list.h>
14#include <linux/mm.h>
15#include <linux/wait.h>
16#include <linux/sunrpc/auth.h>
17#include <linux/nfs_xdr.h>
18
19/*
20 * Valid flags for a dirty buffer
21 */
22#define PG_BUSY			0
23
24struct nfs_page {
25	struct list_head	wb_hash,	/* Inode */
26				wb_lru,		/* superblock lru list */
27				wb_list,	/* Defines state of page: */
28				*wb_list_head;	/*      read/write/commit */
29	struct file		*wb_file;
30	struct inode		*wb_inode;
31	struct rpc_cred		*wb_cred;
32	struct page		*wb_page;	/* page to read in/write out */
33	wait_queue_head_t	wb_wait;	/* wait queue */
34	unsigned long		wb_timeout;	/* when to read/write/commit */
35	unsigned int		wb_offset,	/* Offset of read/write */
36				wb_bytes,	/* Length of request */
37				wb_count;	/* reference count */
38	unsigned long		wb_flags;
39	struct nfs_writeverf	wb_verf;	/* Commit cookie */
40};
41
42#define NFS_WBACK_BUSY(req)	(test_bit(PG_BUSY,&(req)->wb_flags))
43
44extern	struct nfs_page *nfs_create_request(struct rpc_cred *, struct inode *,
45					    struct page *,
46					    unsigned int, unsigned int);
47extern	void nfs_clear_request(struct nfs_page *req);
48extern	void nfs_release_request(struct nfs_page *req);
49
50
51extern	void nfs_list_add_request(struct nfs_page *, struct list_head *);
52
53extern	int nfs_scan_lru(struct list_head *, struct list_head *, int);
54extern	int nfs_scan_lru_timeout(struct list_head *, struct list_head *, int);
55extern	int nfs_scan_list(struct list_head *, struct list_head *,
56			  struct file *, unsigned long, unsigned int);
57extern	int nfs_coalesce_requests(struct list_head *, struct list_head *,
58				  unsigned int);
59extern  int nfs_wait_on_request(struct nfs_page *);
60
61extern	spinlock_t nfs_wreq_lock;
62
63/*
64 * Lock the page of an asynchronous request without incrementing the wb_count
65 */
66static inline int
67nfs_lock_request_dontget(struct nfs_page *req)
68{
69	if (test_and_set_bit(PG_BUSY, &req->wb_flags))
70		return 0;
71	return 1;
72}
73
74/*
75 * Lock the page of an asynchronous request
76 */
77static inline int
78nfs_lock_request(struct nfs_page *req)
79{
80	if (test_and_set_bit(PG_BUSY, &req->wb_flags))
81		return 0;
82	req->wb_count++;
83	return 1;
84}
85
86static inline void
87nfs_unlock_request(struct nfs_page *req)
88{
89	if (!NFS_WBACK_BUSY(req)) {
90		printk(KERN_ERR "NFS: Invalid unlock attempted\n");
91		BUG();
92	}
93	smp_mb__before_clear_bit();
94	clear_bit(PG_BUSY, &req->wb_flags);
95	smp_mb__after_clear_bit();
96	if (waitqueue_active(&req->wb_wait))
97		wake_up_all(&req->wb_wait);
98	nfs_release_request(req);
99}
100
101/**
102 * nfs_list_remove_request - Remove a request from its wb_list
103 * @req: request
104 */
105static inline void
106nfs_list_remove_request(struct nfs_page *req)
107{
108	if (list_empty(&req->wb_list))
109		return;
110	if (!NFS_WBACK_BUSY(req)) {
111		printk(KERN_ERR "NFS: unlocked request attempted removed from list!\n");
112		BUG();
113	}
114	list_del_init(&req->wb_list);
115	req->wb_list_head = NULL;
116}
117
118static inline struct nfs_page *
119nfs_list_entry(struct list_head *head)
120{
121	return list_entry(head, struct nfs_page, wb_list);
122}
123
124static inline struct nfs_page *
125nfs_inode_wb_entry(struct list_head *head)
126{
127	return list_entry(head, struct nfs_page, wb_hash);
128}
129
130static inline void
131__nfs_add_lru(struct list_head *head, struct nfs_page *req)
132{
133	list_add_tail(&req->wb_lru, head);
134}
135
136static inline void
137__nfs_del_lru(struct nfs_page *req)
138{
139	if (list_empty(&req->wb_lru))
140		return;
141	list_del_init(&req->wb_lru);
142}
143
144static inline struct nfs_page *
145nfs_lru_entry(struct list_head *head)
146{
147        return list_entry(head, struct nfs_page, wb_lru);
148}
149
150#endif /* _LINUX_NFS_PAGE_H */
151