LXR linux/include/linux/nfs

   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 the radix tree
  23 */
  24#define NFS_PAGE_TAG_LOCKED     0
  25#define NFS_PAGE_TAG_COMMIT     1
  26
  27/*
  28 * Valid flags for a dirty buffer
  29 */
  30enum {
  31        PG_BUSY = 0,
  32        PG_CLEAN,
  33        PG_NEED_COMMIT,
  34        PG_NEED_RESCHED,
  35};
  36
  37struct nfs_inode;
  38struct nfs_page {
  39        struct list_head        wb_list;        /* Defines state of page: */
  40        struct page             *wb_page;       /* page to read in/write out */
  41        struct nfs_open_context *wb_context;    /* File state context info */
  42        atomic_t                wb_complete;    /* i/os we're waiting for */
  43        pgoff_t                 wb_index;       /* Offset >> PAGE_CACHE_SHIFT */
  44        unsigned int            wb_offset,      /* Offset & ~PAGE_CACHE_MASK */
  45                                wb_pgbase,      /* Start of page data */
  46                                wb_bytes;       /* Length of request */
  47        struct kref             wb_kref;        /* reference count */
  48        unsigned long           wb_flags;
  49        struct nfs_writeverf    wb_verf;        /* Commit cookie */
  50};
  51
  52struct nfs_pageio_descriptor {
  53        struct list_head        pg_list;
  54        unsigned long           pg_bytes_written;
  55        size_t                  pg_count;
  56        size_t                  pg_bsize;
  57        unsigned int            pg_base;
  58
  59        struct inode            *pg_inode;
  60        int                     (*pg_doio)(struct inode *, struct list_head *, unsigned int, size_t, int);
  61        int                     pg_ioflags;
  62        int                     pg_error;
  63};
  64
  65#define NFS_WBACK_BUSY(req)     (test_bit(PG_BUSY,&(req)->wb_flags))
  66
  67extern  struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
  68                                            struct inode *inode,
  69                                            struct page *page,
  70                                            unsigned int offset,
  71                                            unsigned int count);
  72extern  void nfs_clear_request(struct nfs_page *req);
  73extern  void nfs_release_request(struct nfs_page *req);
  74
  75
  76extern  int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *dst,
  77                          pgoff_t idx_start, unsigned int npages, int tag);
  78extern  void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
  79                             struct inode *inode,
  80                             int (*doio)(struct inode *, struct list_head *, unsigned int, size_t, int),
  81                             size_t bsize,
  82                             int how);
  83extern  int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
  84                                   struct nfs_page *);
  85extern  void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
  86extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
  87extern  int nfs_wait_on_request(struct nfs_page *);
  88extern  void nfs_unlock_request(struct nfs_page *req);
  89extern  int nfs_set_page_tag_locked(struct nfs_page *req);
  90extern  void nfs_clear_page_tag_locked(struct nfs_page *req);
  91
  92
  93/*
  94 * Lock the page of an asynchronous request without getting a new reference
  95 */
  96static inline int
  97nfs_lock_request_dontget(struct nfs_page *req)
  98{
  99        return !test_and_set_bit(PG_BUSY, &req->wb_flags);
 100}
 101
 102/**
 103 * nfs_list_add_request - Insert a request into a list
 104 * @req: request
 105 * @head: head of list into which to insert the request.
 106 */
 107static inline void
 108nfs_list_add_request(struct nfs_page *req, struct list_head *head)
 109{
 110        list_add_tail(&req->wb_list, head);
 111}
 112
 113
 114/**
 115 * nfs_list_remove_request - Remove a request from its wb_list
 116 * @req: request
 117 */
 118static inline void
 119nfs_list_remove_request(struct nfs_page *req)
 120{
 121        if (list_empty(&req->wb_list))
 122                return;
 123        list_del_init(&req->wb_list);
 124}
 125
 126static inline struct nfs_page *
 127nfs_list_entry(struct list_head *head)
 128{
 129        return list_entry(head, struct nfs_page, wb_list);
 130}
 131
 132static inline
 133loff_t req_offset(struct nfs_page *req)
 134{
 135        return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
 136}
 137
 138#endif /* _LINUX_NFS_PAGE_H */
 139