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