include/linux/nfs_page.h

   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
  24 struct nfs_page {
  25         struct list_head        wb_hash,        /* Inode */
  26                                 wb_list,        /* Defines state of page: */
  27                                 *wb_list_head;  /*      read/write/commit */
  28         struct file             *wb_file;
  29         struct inode            *wb_inode;
  30         struct rpc_cred         *wb_cred;
  31         struct page             *wb_page;       /* page to read in/write out */
  32         wait_queue_head_t       wb_wait;        /* wait queue */
  33         unsigned long           wb_timeout;     /* when to read/write/commit */
  34         unsigned int            wb_offset,      /* Offset of read/write */
  35                                 wb_bytes,       /* Length of request */
  36                                 wb_count,       /* reference count */
  37                                 wb_flags;
  38         struct nfs_writeverf    wb_verf;        /* Commit cookie */
  39 };
  40
  41 #define NFS_WBACK_BUSY(req)     (test_bit(PG_BUSY,&(req)->wb_flags))
  42
  43 extern  struct nfs_page *nfs_create_request(struct file *file,
  44                                             struct inode *inode,
  45                                             struct page *page,
  46                                             unsigned int offset,
  47                                             unsigned int count);
  48 extern  void nfs_release_request(struct nfs_page *req);
  49
  50
  51 extern  void nfs_list_add_request(struct nfs_page *req,
  52                                   struct list_head *head);
  53 extern  void nfs_list_remove_request(struct nfs_page *req);
  54
  55 extern  int nfs_scan_list_timeout(struct list_head *head,
  56                                   struct list_head *dst,
  57                                   struct inode *inode);
  58 extern  int nfs_scan_list(struct list_head *src, struct list_head *dst,
  59                           struct file *file, unsigned long idx_start,
  60                           unsigned int npages);
  61 extern  int nfs_coalesce_requests(struct list_head *src, struct list_head *dst,
  62                                   unsigned int maxpages);
  63
  64 extern  spinlock_t nfs_wreq_lock;
  65
  66 /*
  67  * Lock the page of an asynchronous request
  68  */
  69 static __inline__ int
  70 nfs_lock_request(struct nfs_page *req)
  71 {
  72         if (test_and_set_bit(PG_BUSY, &req->wb_flags))
  73                 return 0;
  74         req->wb_count++;
  75         return 1;
  76 }
  77
  78 static __inline__ void
  79 nfs_unlock_request(struct nfs_page *req)
  80 {
  81         if (!NFS_WBACK_BUSY(req)) {
  82                 printk(KERN_ERR "NFS: Invalid unlock attempted\n");
  83                 BUG();
  84         }
  85         smp_mb__before_clear_bit();
  86         clear_bit(PG_BUSY, &req->wb_flags);
  87         smp_mb__after_clear_bit();
  88         if (waitqueue_active(&req->wb_wait))
  89                 wake_up(&req->wb_wait);
  90         nfs_release_request(req);
  91 }
  92
  93 static __inline__ struct nfs_page *
  94 nfs_list_entry(struct list_head *head)
  95 {
  96         return list_entry(head, struct nfs_page, wb_list);
  97 }
  98
  99 static __inline__ struct nfs_page *
 100 nfs_inode_wb_entry(struct list_head *head)
 101 {
 102         return list_entry(head, struct nfs_page, wb_hash);
 103 }
 104
 105 #endif /* _LINUX_NFS_PAGE_H */