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_COMMIT     1
  25
  26 /*
  27  * Valid flags for a dirty buffer
  28  */
  29 enum {
  30         PG_BUSY = 0,
  31         PG_MAPPED,
  32         PG_CLEAN,
  33         PG_NEED_COMMIT,
  34         PG_NEED_RESCHED,
  35         PG_PNFS_COMMIT,
  36         PG_PARTIAL_READ_FAILED,
  37 };
  38
  39 struct nfs_inode;
  40 struct nfs_page {
  41         union {
  42                 struct list_head        wb_list;        /* Defines state of page: */
  43                 struct pnfs_layout_segment *wb_commit_lseg; /* Used when PG_PNFS_COMMIT set */
  44         };
  45         struct page             *wb_page;       /* page to read in/write out */
  46         struct nfs_open_context *wb_context;    /* File state context info */
  47         struct nfs_lock_context *wb_lock_context;       /* lock context info */
  48         atomic_t                wb_complete;    /* i/os we're waiting for */
  49         pgoff_t                 wb_index;       /* Offset >> PAGE_CACHE_SHIFT */
  50         unsigned int            wb_offset,      /* Offset & ~PAGE_CACHE_MASK */
  51                                 wb_pgbase,      /* Start of page data */
  52                                 wb_bytes;       /* Length of request */
  53         struct kref             wb_kref;        /* reference count */
  54         unsigned long           wb_flags;
  55         struct nfs_writeverf    wb_verf;        /* Commit cookie */
  56 };
  57
  58 struct nfs_pageio_descriptor;
  59 struct nfs_pageio_ops {
  60         void    (*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *);
  61         bool    (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *, struct nfs_page *);
  62         int     (*pg_doio)(struct nfs_pageio_descriptor *);
  63 };
  64
  65 struct nfs_pageio_descriptor {
  66         struct list_head        pg_list;
  67         unsigned long           pg_bytes_written;
  68         size_t                  pg_count;
  69         size_t                  pg_bsize;
  70         unsigned int            pg_base;
  71         unsigned char           pg_moreio : 1,
  72                                 pg_recoalesce : 1;
  73
  74         struct inode            *pg_inode;
  75         const struct nfs_pageio_ops *pg_ops;
  76         int                     pg_ioflags;
  77         int                     pg_error;
  78         const struct rpc_call_ops *pg_rpc_callops;
  79         struct pnfs_layout_segment *pg_lseg;
  80 };
  81
  82 #define NFS_WBACK_BUSY(req)     (test_bit(PG_BUSY,&(req)->wb_flags))
  83
  84 extern  struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
  85                                             struct inode *inode,
  86                                             struct page *page,
  87                                             unsigned int offset,
  88                                             unsigned int count);
  89 extern  void nfs_release_request(struct nfs_page *req);
  90
  91
  92 extern  int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *dst,
  93                           pgoff_t idx_start, unsigned int npages, int tag);
  94 extern  void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
  95                              struct inode *inode,
  96                              const struct nfs_pageio_ops *pg_ops,
  97                              size_t bsize,
  98                              int how);
  99 extern  int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
 100                                    struct nfs_page *);
 101 extern  void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
 102 extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
 103 extern bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
 104                                 struct nfs_page *prev,
 105                                 struct nfs_page *req);
 106 extern  int nfs_wait_on_request(struct nfs_page *);
 107 extern  void nfs_unlock_request(struct nfs_page *req);
 108
 109 /*
 110  * Lock the page of an asynchronous request without getting a new reference
 111  */
 112 static inline int
 113 nfs_lock_request_dontget(struct nfs_page *req)
 114 {
 115         return !test_and_set_bit(PG_BUSY, &req->wb_flags);
 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 */