2 * linux/include/linux/nfs_page.h
4 * Copyright (C) 2000 Trond Myklebust
6 * NFS page cache wrapper.
9 #ifndef _LINUX_NFS_PAGE_H
10 #define _LINUX_NFS_PAGE_H
13 #include <linux/list.h>
14 #include <linux/pagemap.h>
15 #include <linux/wait.h>
16 #include <linux/sunrpc/auth.h>
17 #include <linux/nfs_xdr.h>
19 #include <asm/atomic.h>
22 * Valid flags for the radix tree
24 #define NFS_PAGE_TAG_DIRTY 0
25 #define NFS_PAGE_TAG_WRITEBACK 1
28 * Valid flags for a dirty buffer
31 #define PG_NEED_COMMIT 1
32 #define PG_NEED_RESCHED 2
33 #define PG_NEED_FLUSH 3
37 struct list_head wb_list, /* Defines state of page: */
38 *wb_list_head; /* read/write/commit */
39 struct page *wb_page; /* page to read in/write out */
40 struct nfs_open_context *wb_context; /* File state context info */
41 atomic_t wb_complete; /* i/os we're waiting for */
42 unsigned long wb_index; /* Offset >> PAGE_CACHE_SHIFT */
43 unsigned int wb_offset, /* Offset & ~PAGE_CACHE_MASK */
44 wb_pgbase, /* Start of page data */
45 wb_bytes; /* Length of request */
46 atomic_t wb_count; /* reference count */
47 unsigned long wb_flags;
48 struct nfs_writeverf wb_verf; /* Commit cookie */
51 struct nfs_pageio_descriptor {
52 struct list_head pg_list;
58 #define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags))
60 extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
65 extern void nfs_clear_request(struct nfs_page *req);
66 extern void nfs_release_request(struct nfs_page *req);
69 extern long nfs_scan_dirty(struct address_space *mapping,
70 struct writeback_control *wbc,
71 struct list_head *dst);
72 extern int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *head, struct list_head *dst,
73 unsigned long idx_start, unsigned int npages);
74 extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
76 extern void nfs_pageio_add_list(struct nfs_pageio_descriptor *,
78 extern int nfs_wait_on_request(struct nfs_page *);
79 extern void nfs_unlock_request(struct nfs_page *req);
80 extern int nfs_set_page_writeback_locked(struct nfs_page *req);
81 extern void nfs_clear_page_writeback(struct nfs_page *req);
85 * Lock the page of an asynchronous request without incrementing the wb_count
88 nfs_lock_request_dontget(struct nfs_page *req)
90 return !test_and_set_bit(PG_BUSY, &req->wb_flags);
94 * Lock the page of an asynchronous request
97 nfs_lock_request(struct nfs_page *req)
99 if (test_and_set_bit(PG_BUSY, &req->wb_flags))
101 atomic_inc(&req->wb_count);
106 * nfs_list_add_request - Insert a request into a list
108 * @head: head of list into which to insert the request.
111 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
113 list_add_tail(&req->wb_list, head);
114 req->wb_list_head = head;
119 * nfs_list_remove_request - Remove a request from its wb_list
123 nfs_list_remove_request(struct nfs_page *req)
125 if (list_empty(&req->wb_list))
127 list_del_init(&req->wb_list);
128 req->wb_list_head = NULL;
131 static inline struct nfs_page *
132 nfs_list_entry(struct list_head *head)
134 return list_entry(head, struct nfs_page, wb_list);
138 loff_t req_offset(struct nfs_page *req)
140 return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
143 #endif /* _LINUX_NFS_PAGE_H */