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 #define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags))
52 #define NFS_NEED_COMMIT(req) (test_bit(PG_NEED_COMMIT,&(req)->wb_flags))
53 #define NFS_NEED_RESCHED(req) (test_bit(PG_NEED_RESCHED,&(req)->wb_flags))
55 extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
60 extern void nfs_clear_request(struct nfs_page *req);
61 extern void nfs_release_request(struct nfs_page *req);
64 extern long nfs_scan_dirty(struct address_space *mapping,
65 struct writeback_control *wbc,
66 struct list_head *dst);
67 extern int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *head, struct list_head *dst,
68 unsigned long idx_start, unsigned int npages);
69 extern int nfs_coalesce_requests(struct list_head *, struct list_head *,
71 extern int nfs_wait_on_request(struct nfs_page *);
72 extern void nfs_unlock_request(struct nfs_page *req);
73 extern int nfs_set_page_writeback_locked(struct nfs_page *req);
74 extern void nfs_clear_page_writeback(struct nfs_page *req);
78 * Lock the page of an asynchronous request without incrementing the wb_count
81 nfs_lock_request_dontget(struct nfs_page *req)
83 return !test_and_set_bit(PG_BUSY, &req->wb_flags);
87 * Lock the page of an asynchronous request
90 nfs_lock_request(struct nfs_page *req)
92 if (test_and_set_bit(PG_BUSY, &req->wb_flags))
94 atomic_inc(&req->wb_count);
99 * nfs_list_add_request - Insert a request into a list
101 * @head: head of list into which to insert the request.
104 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
106 list_add_tail(&req->wb_list, head);
107 req->wb_list_head = head;
112 * nfs_list_remove_request - Remove a request from its wb_list
116 nfs_list_remove_request(struct nfs_page *req)
118 if (list_empty(&req->wb_list))
120 list_del_init(&req->wb_list);
121 req->wb_list_head = NULL;
125 nfs_defer_commit(struct nfs_page *req)
127 return !test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags);
131 nfs_clear_commit(struct nfs_page *req)
133 smp_mb__before_clear_bit();
134 clear_bit(PG_NEED_COMMIT, &req->wb_flags);
135 smp_mb__after_clear_bit();
139 nfs_defer_reschedule(struct nfs_page *req)
141 return !test_and_set_bit(PG_NEED_RESCHED, &req->wb_flags);
145 nfs_clear_reschedule(struct nfs_page *req)
147 smp_mb__before_clear_bit();
148 clear_bit(PG_NEED_RESCHED, &req->wb_flags);
149 smp_mb__after_clear_bit();
152 static inline struct nfs_page *
153 nfs_list_entry(struct list_head *head)
155 return list_entry(head, struct nfs_page, wb_list);
159 loff_t req_offset(struct nfs_page *req)
161 return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
164 #endif /* _LINUX_NFS_PAGE_H */