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