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 <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  */
  30 #define PG_BUSY                 0
  31 #define PG_NEED_COMMIT          1
  32 #define PG_NEED_RESCHED         2
  33
  34 struct nfs_inode;
  35 struct nfs_page {
  36         struct list_head        wb_list;        /* Defines state of page: */
  37         struct page             *wb_page;       /* page to read in/write out */
  38         struct nfs_open_context *wb_context;    /* File state context info */
  39         atomic_t                wb_complete;    /* i/os we're waiting for */
  40         pgoff_t                 wb_index;       /* Offset >> PAGE_CACHE_SHIFT */
  41         unsigned int            wb_offset,      /* Offset & ~PAGE_CACHE_MASK */
  42                                 wb_pgbase,      /* Start of page data */
  43                                 wb_bytes;       /* Length of request */
  44         struct kref             wb_kref;        /* reference count */
  45         unsigned long           wb_flags;
  46         struct nfs_writeverf    wb_verf;        /* Commit cookie */
  47 };
  48
  49 struct nfs_pageio_descriptor {
  50         struct list_head        pg_list;
  51         unsigned long           pg_bytes_written;
  52         size_t                  pg_count;
  53         size_t                  pg_bsize;
  54         unsigned int            pg_base;
  55
  56         struct inode            *pg_inode;
  57         int                     (*pg_doio)(struct inode *, struct list_head *, unsigned int, size_t, int);
  58         int                     pg_ioflags;
  59         int                     pg_error;
  60 };
  61
  62 #define NFS_WBACK_BUSY(req)     (test_bit(PG_BUSY,&(req)->wb_flags))
  63
  64 extern  struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
  65                                             struct inode *inode,
  66                                             struct page *page,
  67                                             unsigned int offset,
  68                                             unsigned int count);
  69 extern  void nfs_clear_request(struct nfs_page *req);
  70 extern  void nfs_release_request(struct nfs_page *req);
  71
  72
  73 extern  int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *dst,
  74                           pgoff_t idx_start, unsigned int npages, int tag);
  75 extern  void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
  76                              struct inode *inode,
  77                              int (*doio)(struct inode *, struct list_head *, unsigned int, size_t, int),
  78                              size_t bsize,
  79                              int how);
  80 extern  int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
  81                                    struct nfs_page *);
  82 extern  void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
  83 extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
  84 extern  int nfs_wait_on_request(struct nfs_page *);
  85 extern  void nfs_unlock_request(struct nfs_page *req);
  86 extern  void nfs_clear_page_tag_locked(struct nfs_page *req);
  87
  88
  89 /*
  90  * Lock the page of an asynchronous request without getting a new reference
  91  */
  92 static inline int
  93 nfs_lock_request_dontget(struct nfs_page *req)
  94 {
  95         return !test_and_set_bit(PG_BUSY, &req->wb_flags);
  96 }
  97
  98 /*
  99  * Lock the page of an asynchronous request and take a reference
 100  */
 101 static inline int
 102 nfs_lock_request(struct nfs_page *req)
 103 {
 104         if (test_and_set_bit(PG_BUSY, &req->wb_flags))
 105                 return 0;
 106         kref_get(&req->wb_kref);
 107         return 1;
 108 }
 109
 110 /**
 111  * nfs_list_add_request - Insert a request into a list
 112  * @req: request
 113  * @head: head of list into which to insert the request.
 114  */
 115 static inline void
 116 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
 117 {
 118         list_add_tail(&req->wb_list, head);
 119 }
 120
 121
 122 /**
 123  * nfs_list_remove_request - Remove a request from its wb_list
 124  * @req: request
 125  */
 126 static inline void
 127 nfs_list_remove_request(struct nfs_page *req)
 128 {
 129         if (list_empty(&req->wb_list))
 130                 return;
 131         list_del_init(&req->wb_list);
 132 }
 133
 134 static inline struct nfs_page *
 135 nfs_list_entry(struct list_head *head)
 136 {
 137         return list_entry(head, struct nfs_page, wb_list);
 138 }
 139
 140 static inline
 141 loff_t req_offset(struct nfs_page *req)
 142 {
 143         return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
 144 }
 145
 146 #endif /* _LINUX_NFS_PAGE_H */