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         PG_PNFS_COMMIT,
  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 list_head        pg_list;
  60         unsigned long           pg_bytes_written;
  61         size_t                  pg_count;
  62         size_t                  pg_bsize;
  63         unsigned int            pg_base;
  64         char                    pg_moreio;
  65
  66         struct inode            *pg_inode;
  67         int                     (*pg_doio)(struct nfs_pageio_descriptor *);
  68         int                     pg_ioflags;
  69         int                     pg_error;
  70         struct pnfs_layout_segment *pg_lseg;
  71         int                     (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *, struct nfs_page *);
  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  int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *dst,
  85                           pgoff_t idx_start, unsigned int npages, int tag);
  86 extern  void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
  87                              struct inode *inode,
  88                              int (*doio)(struct nfs_pageio_descriptor *desc),
  89                              size_t bsize,
  90                              int how);
  91 extern  int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
  92                                    struct nfs_page *);
  93 extern  void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
  94 extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
  95 extern  int nfs_wait_on_request(struct nfs_page *);
  96 extern  void nfs_unlock_request(struct nfs_page *req);
  97 extern  int nfs_set_page_tag_locked(struct nfs_page *req);
  98 extern  void nfs_clear_page_tag_locked(struct nfs_page *req);
  99
 100
 101 /*
 102  * Lock the page of an asynchronous request without getting a new reference
 103  */
 104 static inline int
 105 nfs_lock_request_dontget(struct nfs_page *req)
 106 {
 107         return !test_and_set_bit(PG_BUSY, &req->wb_flags);
 108 }
 109
 110 /**
 111  * nfs_list_add_request - Insert a request into a list
 112  * @req: request
 113  * @head: head of list into which to insert the request.
 114  */
 115 static inline void
 116 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
 117 {
 118         list_add_tail(&req->wb_list, head);
 119 }
 120
 121
 122 /**
 123  * nfs_list_remove_request - Remove a request from its wb_list
 124  * @req: request
 125  */
 126 static inline void
 127 nfs_list_remove_request(struct nfs_page *req)
 128 {
 129         if (list_empty(&req->wb_list))
 130                 return;
 131         list_del_init(&req->wb_list);
 132 }
 133
 134 static inline struct nfs_page *
 135 nfs_list_entry(struct list_head *head)
 136 {
 137         return list_entry(head, struct nfs_page, wb_list);
 138 }
 139
 140 static inline
 141 loff_t req_offset(struct nfs_page *req)
 142 {
 143         return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
 144 }
 145
 146 #endif /* _LINUX_NFS_PAGE_H */