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 a dirty buffer
  23  */
  24 enum {
  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
  33 struct nfs_inode;
  34 struct 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         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 nfs_pageio_ops {
  51         void    (*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *);
  52         bool    (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *, struct nfs_page *);
  53         int     (*pg_doio)(struct nfs_pageio_descriptor *);
  54 };
  55
  56 struct nfs_pageio_descriptor {
  57         struct list_head        pg_list;
  58         unsigned long           pg_bytes_written;
  59         size_t                  pg_count;
  60         size_t                  pg_bsize;
  61         unsigned int            pg_base;
  62         unsigned char           pg_moreio : 1,
  63                                 pg_recoalesce : 1;
  64
  65         struct inode            *pg_inode;
  66         const struct nfs_pageio_ops *pg_ops;
  67         int                     pg_ioflags;
  68         int                     pg_error;
  69         const struct rpc_call_ops *pg_rpc_callops;
  70         struct pnfs_layout_segment *pg_lseg;
  71 };
  72
  73 #define NFS_WBACK_BUSY(req)     (test_bit(PG_BUSY,&(req)->wb_flags))
  74
  75 extern  struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
  76                                             struct inode *inode,
  77                                             struct page *page,
  78                                             unsigned int offset,
  79                                             unsigned int count);
  80 extern  void nfs_release_request(struct nfs_page *req);
  81
  82
  83 extern  void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
  84                              struct inode *inode,
  85                              const struct nfs_pageio_ops *pg_ops,
  86                              size_t bsize,
  87                              int how);
  88 extern  int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
  89                                    struct nfs_page *);
  90 extern  void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
  91 extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
  92 extern bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
  93                                 struct nfs_page *prev,
  94                                 struct nfs_page *req);
  95 extern  int nfs_wait_on_request(struct nfs_page *);
  96 extern  void nfs_unlock_request(struct nfs_page *req);
  97
  98 /*
  99  * Lock the page of an asynchronous request without getting a new reference
 100  */
 101 static inline int
 102 nfs_lock_request_dontget(struct nfs_page *req)
 103 {
 104         return !test_and_set_bit(PG_BUSY, &req->wb_flags);
 105 }
 106
 107 static inline int
 108 nfs_lock_request(struct nfs_page *req)
 109 {
 110         if (test_and_set_bit(PG_BUSY, &req->wb_flags))
 111                 return 0;
 112         kref_get(&req->wb_kref);
 113         return 1;
 114 }
 115
 116
 117 /**
 118  * nfs_list_add_request - Insert a request into a list
 119  * @req: request
 120  * @head: head of list into which to insert the request.
 121  */
 122 static inline void
 123 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
 124 {
 125         list_add_tail(&req->wb_list, head);
 126 }
 127
 128
 129 /**
 130  * nfs_list_remove_request - Remove a request from its wb_list
 131  * @req: request
 132  */
 133 static inline void
 134 nfs_list_remove_request(struct nfs_page *req)
 135 {
 136         if (list_empty(&req->wb_list))
 137                 return;
 138         list_del_init(&req->wb_list);
 139 }
 140
 141 static inline struct nfs_page *
 142 nfs_list_entry(struct list_head *head)
 143 {
 144         return list_entry(head, struct nfs_page, wb_list);
 145 }
 146
 147 static inline
 148 loff_t req_offset(struct nfs_page *req)
 149 {
 150         return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
 151 }
 152
 153 #endif /* _LINUX_NFS_PAGE_H */