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         PG_PARTIAL_READ_FAILED,
  38 };
  39
  40 struct nfs_inode;
  41 struct nfs_page {
  42         union {
  43                 struct list_head        wb_list;        /* Defines state of page: */
  44                 struct pnfs_layout_segment *wb_commit_lseg; /* Used when PG_PNFS_COMMIT set */
  45         };
  46         struct page             *wb_page;       /* page to read in/write out */
  47         struct nfs_open_context *wb_context;    /* File state context info */
  48         struct nfs_lock_context *wb_lock_context;       /* lock context info */
  49         atomic_t                wb_complete;    /* i/os we're waiting for */
  50         pgoff_t                 wb_index;       /* Offset >> PAGE_CACHE_SHIFT */
  51         unsigned int            wb_offset,      /* Offset & ~PAGE_CACHE_MASK */
  52                                 wb_pgbase,      /* Start of page data */
  53                                 wb_bytes;       /* Length of request */
  54         struct kref             wb_kref;        /* reference count */
  55         unsigned long           wb_flags;
  56         struct nfs_writeverf    wb_verf;        /* Commit cookie */
  57 };
  58
  59 struct nfs_pageio_descriptor;
  60 struct nfs_pageio_ops {
  61         void    (*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *);
  62         bool    (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *, struct nfs_page *);
  63         int     (*pg_doio)(struct nfs_pageio_descriptor *);
  64 };
  65
  66 struct nfs_pageio_descriptor {
  67         struct list_head        pg_list;
  68         unsigned long           pg_bytes_written;
  69         size_t                  pg_count;
  70         size_t                  pg_bsize;
  71         unsigned int            pg_base;
  72         unsigned char           pg_moreio : 1,
  73                                 pg_recoalesce : 1;
  74
  75         struct inode            *pg_inode;
  76         const struct nfs_pageio_ops *pg_ops;
  77         int                     pg_ioflags;
  78         int                     pg_error;
  79         const struct rpc_call_ops *pg_rpc_callops;
  80         struct pnfs_layout_segment *pg_lseg;
  81 };
  82
  83 #define NFS_WBACK_BUSY(req)     (test_bit(PG_BUSY,&(req)->wb_flags))
  84
  85 extern  struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
  86                                             struct inode *inode,
  87                                             struct page *page,
  88                                             unsigned int offset,
  89                                             unsigned int count);
  90 extern  void nfs_release_request(struct nfs_page *req);
  91
  92
  93 extern  int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *dst,
  94                           pgoff_t idx_start, unsigned int npages, int tag);
  95 extern  void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
  96                              struct inode *inode,
  97                              const struct nfs_pageio_ops *pg_ops,
  98                              size_t bsize,
  99                              int how);
 100 extern  int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
 101                                    struct nfs_page *);
 102 extern  void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
 103 extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
 104 extern bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
 105                                 struct nfs_page *prev,
 106                                 struct nfs_page *req);
 107 extern  int nfs_wait_on_request(struct nfs_page *);
 108 extern  void nfs_unlock_request(struct nfs_page *req);
 109 extern  int nfs_set_page_tag_locked(struct nfs_page *req);
 110 extern  void nfs_clear_page_tag_locked(struct nfs_page *req);
 111
 112 /*
 113  * Lock the page of an asynchronous request without getting a new reference
 114  */
 115 static inline int
 116 nfs_lock_request_dontget(struct nfs_page *req)
 117 {
 118         return !test_and_set_bit(PG_BUSY, &req->wb_flags);
 119 }
 120
 121 /**
 122  * nfs_list_add_request - Insert a request into a list
 123  * @req: request
 124  * @head: head of list into which to insert the request.
 125  */
 126 static inline void
 127 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
 128 {
 129         list_add_tail(&req->wb_list, head);
 130 }
 131
 132
 133 /**
 134  * nfs_list_remove_request - Remove a request from its wb_list
 135  * @req: request
 136  */
 137 static inline void
 138 nfs_list_remove_request(struct nfs_page *req)
 139 {
 140         if (list_empty(&req->wb_list))
 141                 return;
 142         list_del_init(&req->wb_list);
 143 }
 144
 145 static inline struct nfs_page *
 146 nfs_list_entry(struct list_head *head)
 147 {
 148         return list_entry(head, struct nfs_page, wb_list);
 149 }
 150
 151 static inline
 152 loff_t req_offset(struct nfs_page *req)
 153 {
 154         return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
 155 }
 156
 157 #endif /* _LINUX_NFS_PAGE_H */