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/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
  34 struct nfs_inode;
  35 struct 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
  50 struct 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
  65 extern  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);
  70 extern  void nfs_clear_request(struct nfs_page *req);
  71 extern  void nfs_release_request(struct nfs_page *req);
  72
  73
  74 extern  int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *head, struct list_head *dst,
  75                           pgoff_t idx_start, unsigned int npages);
  76 extern  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);
  81 extern  int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
  82                                    struct nfs_page *);
  83 extern  void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
  84 extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
  85 extern  int nfs_wait_on_request(struct nfs_page *);
  86 extern  void nfs_unlock_request(struct nfs_page *req);
  87 extern  int nfs_set_page_writeback_locked(struct nfs_page *req);
  88 extern  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  */
  94 static inline int
  95 nfs_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  */
 103 static inline int
 104 nfs_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  */
 117 static inline void
 118 nfs_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  */
 129 static inline void
 130 nfs_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
 138 static inline struct nfs_page *
 139 nfs_list_entry(struct list_head *head)
 140 {
 141         return list_entry(head, struct nfs_page, wb_list);
 142 }
 143
 144 static inline
 145 loff_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 */