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         const struct nfs_pgio_completion_ops *pg_completion_ops;
  71         struct pnfs_layout_segment *pg_lseg;
  72 };
  73
  74 #define NFS_WBACK_BUSY(req)     (test_bit(PG_BUSY,&(req)->wb_flags))
  75
  76 extern  struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
  77                                             struct inode *inode,
  78                                             struct page *page,
  79                                             unsigned int offset,
  80                                             unsigned int count);
  81 extern  void nfs_release_request(struct nfs_page *req);
  82
  83
  84 extern  void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
  85                              struct inode *inode,
  86                              const struct nfs_pageio_ops *pg_ops,
  87                              const struct nfs_pgio_completion_ops *compl_ops,
  88                              size_t bsize,
  89                              int how);
  90 extern  int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
  91                                    struct nfs_page *);
  92 extern  void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
  93 extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
  94 extern bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
  95                                 struct nfs_page *prev,
  96                                 struct nfs_page *req);
  97 extern  int nfs_wait_on_request(struct nfs_page *);
  98 extern  void nfs_unlock_request(struct nfs_page *req);
  99
 100 /*
 101  * Lock the page of an asynchronous request without getting a new reference
 102  */
 103 static inline int
 104 nfs_lock_request_dontget(struct nfs_page *req)
 105 {
 106         return !test_and_set_bit(PG_BUSY, &req->wb_flags);
 107 }
 108
 109 static inline int
 110 nfs_lock_request(struct nfs_page *req)
 111 {
 112         if (test_and_set_bit(PG_BUSY, &req->wb_flags))
 113                 return 0;
 114         kref_get(&req->wb_kref);
 115         return 1;
 116 }
 117
 118
 119 /**
 120  * nfs_list_add_request - Insert a request into a list
 121  * @req: request
 122  * @head: head of list into which to insert the request.
 123  */
 124 static inline void
 125 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
 126 {
 127         list_add_tail(&req->wb_list, head);
 128 }
 129
 130
 131 /**
 132  * nfs_list_remove_request - Remove a request from its wb_list
 133  * @req: request
 134  */
 135 static inline void
 136 nfs_list_remove_request(struct nfs_page *req)
 137 {
 138         if (list_empty(&req->wb_list))
 139                 return;
 140         list_del_init(&req->wb_list);
 141 }
 142
 143 static inline struct nfs_page *
 144 nfs_list_entry(struct list_head *head)
 145 {
 146         return list_entry(head, struct nfs_page, wb_list);
 147 }
 148
 149 static inline
 150 loff_t req_offset(struct nfs_page *req)
 151 {
 152         return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
 153 }
 154
 155 #endif /* _LINUX_NFS_PAGE_H */