linux/include/linux/nfs_page.h
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   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 <linux/kref.h>
  20
  21/*
  22 * Valid flags for a dirty buffer
  23 */
  24enum {
  25        PG_BUSY = 0,
  26        PG_MAPPED,
  27        PG_CLEAN,
  28        PG_NEED_COMMIT,
  29        PG_NEED_RESCHED,
  30        PG_COMMIT_TO_DS,
  31};
  32
  33struct nfs_inode;
  34struct nfs_page {
  35        struct list_head        wb_list;        /* Defines state of page: */
  36        struct page             *wb_page;       /* page to read in/write out */
  37        struct nfs_open_context *wb_context;    /* File state context info */
  38        struct nfs_lock_context *wb_lock_context;       /* lock context info */
  39        pgoff_t                 wb_index;       /* Offset >> PAGE_CACHE_SHIFT */
  40        unsigned int            wb_offset,      /* Offset & ~PAGE_CACHE_MASK */
  41                                wb_pgbase,      /* Start of page data */
  42                                wb_bytes;       /* Length of request */
  43        struct kref             wb_kref;        /* reference count */
  44        unsigned long           wb_flags;
  45        struct nfs_write_verifier       wb_verf;        /* Commit cookie */
  46};
  47
  48struct nfs_pageio_descriptor;
  49struct nfs_pageio_ops {
  50        void    (*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *);
  51        bool    (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *, struct nfs_page *);
  52        int     (*pg_doio)(struct nfs_pageio_descriptor *);
  53};
  54
  55struct nfs_pageio_descriptor {
  56        struct list_head        pg_list;
  57        unsigned long           pg_bytes_written;
  58        size_t                  pg_count;
  59        size_t                  pg_bsize;
  60        unsigned int            pg_base;
  61        unsigned char           pg_moreio : 1,
  62                                pg_recoalesce : 1;
  63
  64        struct inode            *pg_inode;
  65        const struct nfs_pageio_ops *pg_ops;
  66        int                     pg_ioflags;
  67        int                     pg_error;
  68        const struct rpc_call_ops *pg_rpc_callops;
  69        const struct nfs_pgio_completion_ops *pg_completion_ops;
  70        struct pnfs_layout_segment *pg_lseg;
  71        struct nfs_direct_req   *pg_dreq;
  72        void                    *pg_layout_private;
  73};
  74
  75#define NFS_WBACK_BUSY(req)     (test_bit(PG_BUSY,&(req)->wb_flags))
  76
  77extern  struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
  78                                            struct inode *inode,
  79                                            struct page *page,
  80                                            unsigned int offset,
  81                                            unsigned int count);
  82extern  void nfs_release_request(struct nfs_page *req);
  83
  84
  85extern  void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
  86                             struct inode *inode,
  87                             const struct nfs_pageio_ops *pg_ops,
  88                             const struct nfs_pgio_completion_ops *compl_ops,
  89                             size_t bsize,
  90                             int how);
  91extern  int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
  92                                   struct nfs_page *);
  93extern  void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
  94extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
  95extern bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
  96                                struct nfs_page *prev,
  97                                struct nfs_page *req);
  98extern  int nfs_wait_on_request(struct nfs_page *);
  99extern  void nfs_unlock_request(struct nfs_page *req);
 100extern  void nfs_unlock_and_release_request(struct nfs_page *req);
 101
 102/*
 103 * Lock the page of an asynchronous request
 104 */
 105static inline int
 106nfs_lock_request(struct nfs_page *req)
 107{
 108        return !test_and_set_bit(PG_BUSY, &req->wb_flags);
 109}
 110
 111/**
 112 * nfs_list_add_request - Insert a request into a list
 113 * @req: request
 114 * @head: head of list into which to insert the request.
 115 */
 116static inline void
 117nfs_list_add_request(struct nfs_page *req, struct list_head *head)
 118{
 119        list_add_tail(&req->wb_list, head);
 120}
 121
 122
 123/**
 124 * nfs_list_remove_request - Remove a request from its wb_list
 125 * @req: request
 126 */
 127static inline void
 128nfs_list_remove_request(struct nfs_page *req)
 129{
 130        if (list_empty(&req->wb_list))
 131                return;
 132        list_del_init(&req->wb_list);
 133}
 134
 135static inline struct nfs_page *
 136nfs_list_entry(struct list_head *head)
 137{
 138        return list_entry(head, struct nfs_page, wb_list);
 139}
 140
 141static inline
 142loff_t req_offset(struct nfs_page *req)
 143{
 144        return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
 145}
 146
 147#endif /* _LINUX_NFS_PAGE_H */
 148
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