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/nfs_fs_sb.h> 17 #include <linux/sunrpc/auth.h> 18 #include <linux/nfs_xdr.h> 19 20 #include <asm/atomic.h> 21 22 /* 23 * Valid flags for the radix tree 24 */ 25 #define NFS_PAGE_TAG_DIRTY 0 26 #define NFS_PAGE_TAG_WRITEBACK 1 27 28 /* 29 * Valid flags for a dirty buffer 30 */ 31 #define PG_BUSY 0 32 #define PG_NEED_COMMIT 1 33 #define PG_NEED_RESCHED 2 34 35 struct nfs_inode; 36 struct nfs_page { 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 */ 49 }; 50 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)) 54 55 extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx, 56 struct inode *inode, 57 struct page *page, 58 unsigned int offset, 59 unsigned int count); 60 extern void nfs_clear_request(struct nfs_page *req); 61 extern void nfs_release_request(struct nfs_page *req); 62 63 64 extern int nfs_scan_lock_dirty(struct nfs_inode *nfsi, struct list_head *dst, 65 unsigned long idx_start, unsigned int npages); 66 extern int nfs_scan_list(struct list_head *, struct list_head *, 67 unsigned long, unsigned int); 68 extern int nfs_coalesce_requests(struct list_head *, struct list_head *, 69 unsigned int); 70 extern int nfs_wait_on_request(struct nfs_page *); 71 extern void nfs_unlock_request(struct nfs_page *req); 72 extern int nfs_set_page_writeback_locked(struct nfs_page *req); 73 extern void nfs_clear_page_writeback(struct nfs_page *req); 74 75 76 /* 77 * Lock the page of an asynchronous request without incrementing the wb_count 78 */ 79 static inline int 80 nfs_lock_request_dontget(struct nfs_page *req) 81 { 82 return !test_and_set_bit(PG_BUSY, &req->wb_flags); 83 } 84 85 /* 86 * Lock the page of an asynchronous request 87 */ 88 static inline int 89 nfs_lock_request(struct nfs_page *req) 90 { 91 if (test_and_set_bit(PG_BUSY, &req->wb_flags)) 92 return 0; 93 atomic_inc(&req->wb_count); 94 return 1; 95 } 96 97 /** 98 * nfs_list_add_request - Insert a request into a list 99 * @req: request 100 * @head: head of list into which to insert the request. 101 */ 102 static inline void 103 nfs_list_add_request(struct nfs_page *req, struct list_head *head) 104 { 105 list_add_tail(&req->wb_list, head); 106 req->wb_list_head = head; 107 } 108 109 110 /** 111 * nfs_list_remove_request - Remove a request from its wb_list 112 * @req: request 113 */ 114 static inline void 115 nfs_list_remove_request(struct nfs_page *req) 116 { 117 if (list_empty(&req->wb_list)) 118 return; 119 list_del_init(&req->wb_list); 120 req->wb_list_head = NULL; 121 } 122 123 static inline int 124 nfs_defer_commit(struct nfs_page *req) 125 { 126 return !test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags); 127 } 128 129 static inline void 130 nfs_clear_commit(struct nfs_page *req) 131 { 132 smp_mb__before_clear_bit(); 133 clear_bit(PG_NEED_COMMIT, &req->wb_flags); 134 smp_mb__after_clear_bit(); 135 } 136 137 static inline int 138 nfs_defer_reschedule(struct nfs_page *req) 139 { 140 return !test_and_set_bit(PG_NEED_RESCHED, &req->wb_flags); 141 } 142 143 static inline void 144 nfs_clear_reschedule(struct nfs_page *req) 145 { 146 smp_mb__before_clear_bit(); 147 clear_bit(PG_NEED_RESCHED, &req->wb_flags); 148 smp_mb__after_clear_bit(); 149 } 150 151 static inline struct nfs_page * 152 nfs_list_entry(struct list_head *head) 153 { 154 return list_entry(head, struct nfs_page, wb_list); 155 } 156 157 static inline 158 loff_t req_offset(struct nfs_page *req) 159 { 160 return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset; 161 } 162 163 #endif /* _LINUX_NFS_PAGE_H */ 164