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_PARTIAL_READ_FAILED,
  31         PG_COMMIT_TO_DS,
  32 };
  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         struct nfs_lock_context *wb_lock_context;       /* lock context info */
  40         atomic_t                wb_complete;    /* i/os we're waiting for */
  41         pgoff_t                 wb_index;       /* Offset >> PAGE_CACHE_SHIFT */
  42         unsigned int            wb_offset,      /* Offset & ~PAGE_CACHE_MASK */
  43                                 wb_pgbase,      /* Start of page data */
  44                                 wb_bytes;       /* Length of request */
  45         struct kref             wb_kref;        /* reference count */
  46         unsigned long           wb_flags;
  47         struct nfs_writeverf    wb_verf;        /* Commit cookie */
  48 };
  49
  50 struct nfs_pageio_descriptor;
  51 struct nfs_pageio_ops {
  52         void    (*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *);
  53         bool    (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *, struct nfs_page *);
  54         int     (*pg_doio)(struct nfs_pageio_descriptor *);
  55 };
  56
  57 struct nfs_pageio_descriptor {
  58         struct list_head        pg_list;
  59         unsigned long           pg_bytes_written;
  60         size_t                  pg_count;
  61         size_t                  pg_bsize;
  62         unsigned int            pg_base;
  63         unsigned char           pg_moreio : 1,
  64                                 pg_recoalesce : 1;
  65
  66         struct inode            *pg_inode;
  67         const struct nfs_pageio_ops *pg_ops;
  68         int                     pg_ioflags;
  69         int                     pg_error;
  70         const struct rpc_call_ops *pg_rpc_callops;
  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                              size_t bsize,
  88                              int how);
  89 extern  int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
  90                                    struct nfs_page *);
  91 extern  void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
  92 extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
  93 extern bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
  94                                 struct nfs_page *prev,
  95                                 struct nfs_page *req);
  96 extern  int nfs_wait_on_request(struct nfs_page *);
  97 extern  void nfs_unlock_request(struct nfs_page *req);
  98
  99 /*
 100  * Lock the page of an asynchronous request without getting a new reference
 101  */
 102 static inline int
 103 nfs_lock_request_dontget(struct nfs_page *req)
 104 {
 105         return !test_and_set_bit(PG_BUSY, &req->wb_flags);
 106 }
 107
 108 static inline int
 109 nfs_lock_request(struct nfs_page *req)
 110 {
 111         if (test_and_set_bit(PG_BUSY, &req->wb_flags))
 112                 return 0;
 113         kref_get(&req->wb_kref);
 114         return 1;
 115 }
 116
 117
 118 /**
 119  * nfs_list_add_request - Insert a request into a list
 120  * @req: request
 121  * @head: head of list into which to insert the request.
 122  */
 123 static inline void
 124 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
 125 {
 126         list_add_tail(&req->wb_list, head);
 127 }
 128
 129
 130 /**
 131  * nfs_list_remove_request - Remove a request from its wb_list
 132  * @req: request
 133  */
 134 static inline void
 135 nfs_list_remove_request(struct nfs_page *req)
 136 {
 137         if (list_empty(&req->wb_list))
 138                 return;
 139         list_del_init(&req->wb_list);
 140 }
 141
 142 static inline struct nfs_page *
 143 nfs_list_entry(struct list_head *head)
 144 {
 145         return list_entry(head, struct nfs_page, wb_list);
 146 }
 147
 148 static inline
 149 loff_t req_offset(struct nfs_page *req)
 150 {
 151         return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
 152 }
 153
 154 #endif /* _LINUX_NFS_PAGE_H */