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/pagemap.h> 15#include <linux/wait.h> 16#include <linux/sunrpc/auth.h> 17#include <linux/nfs_xdr.h> 18 19#include <asm/atomic.h> 20 21/* 22 * Valid flags for the radix tree 23 */ 24#define NFS_PAGE_TAG_WRITEBACK 0 25 26/* 27 * Valid flags for a dirty buffer 28 */ 29#define PG_BUSY 0 30#define PG_NEED_COMMIT 1 31#define PG_NEED_RESCHED 2 32#define PG_NEED_FLUSH 3 33 34struct nfs_inode; 35struct nfs_page { 36 struct list_head wb_list, /* Defines state of page: */ 37 *wb_list_head; /* read/write/commit */ 38 struct page *wb_page; /* page to read in/write out */ 39 struct nfs_open_context *wb_context; /* File state context info */ 40 atomic_t wb_complete; /* i/os we're waiting for */ 41 pgoff_t wb_index; /* Offset >> PAGE_CACHE_SHIFT */ 42 unsigned int wb_offset, /* Offset & ~PAGE_CACHE_MASK */ 43 wb_pgbase, /* Start of page data */ 44 wb_bytes; /* Length of request */ 45 atomic_t wb_count; /* reference count */ 46 unsigned long wb_flags; 47 struct nfs_writeverf wb_verf; /* Commit cookie */ 48}; 49 50struct nfs_pageio_descriptor { 51 struct list_head pg_list; 52 unsigned long pg_bytes_written; 53 size_t pg_count; 54 size_t pg_bsize; 55 unsigned int pg_base; 56 57 struct inode *pg_inode; 58 int (*pg_doio)(struct inode *, struct list_head *, unsigned int, size_t, int); 59 int pg_ioflags; 60 int pg_error; 61}; 62 63#define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags)) 64 65extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx, 66 struct inode *inode, 67 struct page *page, 68 unsigned int offset, 69 unsigned int count); 70extern void nfs_clear_request(struct nfs_page *req); 71extern void nfs_release_request(struct nfs_page *req); 72 73 74extern int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *head, struct list_head *dst, 75 pgoff_t idx_start, unsigned int npages); 76extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc, 77 struct inode *inode, 78 int (*doio)(struct inode *, struct list_head *, unsigned int, size_t, int), 79 size_t bsize, 80 int how); 81extern int nfs_pageio_add_request(struct nfs_pageio_descriptor *, 82 struct nfs_page *); 83extern void nfs_pageio_complete(struct nfs_pageio_descriptor *desc); 84extern void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t); 85extern int nfs_wait_on_request(struct nfs_page *); 86extern void nfs_unlock_request(struct nfs_page *req); 87extern int nfs_set_page_writeback_locked(struct nfs_page *req); 88extern void nfs_clear_page_writeback(struct nfs_page *req); 89 90 91/* 92 * Lock the page of an asynchronous request without incrementing the wb_count 93 */ 94static inline int 95nfs_lock_request_dontget(struct nfs_page *req) 96{ 97 return !test_and_set_bit(PG_BUSY, &req->wb_flags); 98} 99 100/* 101 * Lock the page of an asynchronous request 102 */ 103static inline int 104nfs_lock_request(struct nfs_page *req) 105{ 106 if (test_and_set_bit(PG_BUSY, &req->wb_flags)) 107 return 0; 108 atomic_inc(&req->wb_count); 109 return 1; 110} 111 112/** 113 * nfs_list_add_request - Insert a request into a list 114 * @req: request 115 * @head: head of list into which to insert the request. 116 */ 117static inline void 118nfs_list_add_request(struct nfs_page *req, struct list_head *head) 119{ 120 list_add_tail(&req->wb_list, head); 121 req->wb_list_head = head; 122} 123 124 125/** 126 * nfs_list_remove_request - Remove a request from its wb_list 127 * @req: request 128 */ 129static inline void 130nfs_list_remove_request(struct nfs_page *req) 131{ 132 if (list_empty(&req->wb_list)) 133 return; 134 list_del_init(&req->wb_list); 135 req->wb_list_head = NULL; 136} 137 138static inline struct nfs_page * 139nfs_list_entry(struct list_head *head) 140{ 141 return list_entry(head, struct nfs_page, wb_list); 142} 143 144static inline 145loff_t req_offset(struct nfs_page *req) 146{ 147 return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset; 148} 149 150#endif /* _LINUX_NFS_PAGE_H */ 151