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,            /* nfs_{un}lock_request */
  26         PG_MAPPED,              /* page private set for buffered io */
  27         PG_CLEAN,               /* write succeeded */
  28         PG_COMMIT_TO_DS,        /* used by pnfs layouts */
  29         PG_INODE_REF,           /* extra ref held by inode when in writeback */
  30         PG_HEADLOCK,            /* page group lock of wb_head */
  31         PG_TEARDOWN,            /* page group sync for destroy */
  32         PG_UNLOCKPAGE,          /* page group sync bit in read path */
  33         PG_UPTODATE,            /* page group sync bit in read path */
  34         PG_WB_END,              /* page group sync bit in write path */
  35         PG_REMOVE,              /* page group sync bit in write path */
  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         pgoff_t                 wb_index;       /* Offset >> PAGE_CACHE_SHIFT */
  45         unsigned int            wb_offset,      /* Offset & ~PAGE_CACHE_MASK */
  46                                 wb_pgbase,      /* Start of page data */
  47                                 wb_bytes;       /* Length of request */
  48         struct kref             wb_kref;        /* reference count */
  49         unsigned long           wb_flags;
  50         struct nfs_write_verifier       wb_verf;        /* Commit cookie */
  51         struct nfs_page         *wb_this_page;  /* list of reqs for this page */
  52         struct nfs_page         *wb_head;       /* head pointer for req list */
  53 };
  54
  55 struct nfs_pageio_descriptor;
  56 struct nfs_pageio_ops {
  57         void    (*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *);
  58         size_t  (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *,
  59                            struct nfs_page *);
  60         int     (*pg_doio)(struct nfs_pageio_descriptor *);
  61 };
  62
  63 struct nfs_rw_ops {
  64         const fmode_t rw_mode;
  65         struct nfs_pgio_header *(*rw_alloc_header)(void);
  66         void (*rw_free_header)(struct nfs_pgio_header *);
  67         void (*rw_release)(struct nfs_pgio_header *);
  68         int  (*rw_done)(struct rpc_task *, struct nfs_pgio_header *,
  69                         struct inode *);
  70         void (*rw_result)(struct rpc_task *, struct nfs_pgio_header *);
  71         void (*rw_initiate)(struct nfs_pgio_header *, struct rpc_message *,
  72                             struct rpc_task_setup *, int);
  73 };
  74
  75 struct nfs_pageio_descriptor {
  76         struct list_head        pg_list;
  77         unsigned long           pg_bytes_written;
  78         size_t                  pg_count;
  79         size_t                  pg_bsize;
  80         unsigned int            pg_base;
  81         unsigned char           pg_moreio : 1,
  82                                 pg_recoalesce : 1;
  83
  84         struct inode            *pg_inode;
  85         const struct nfs_pageio_ops *pg_ops;
  86         const struct nfs_rw_ops *pg_rw_ops;
  87         int                     pg_ioflags;
  88         int                     pg_error;
  89         const struct rpc_call_ops *pg_rpc_callops;
  90         const struct nfs_pgio_completion_ops *pg_completion_ops;
  91         struct pnfs_layout_segment *pg_lseg;
  92         struct nfs_direct_req   *pg_dreq;
  93         void                    *pg_layout_private;
  94 };
  95
  96 #define NFS_WBACK_BUSY(req)     (test_bit(PG_BUSY,&(req)->wb_flags))
  97
  98 extern  struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
  99                                             struct page *page,
 100                                             struct nfs_page *last,
 101                                             unsigned int offset,
 102                                             unsigned int count);
 103 extern  void nfs_release_request(struct nfs_page *);
 104
 105
 106 extern  void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
 107                              struct inode *inode,
 108                              const struct nfs_pageio_ops *pg_ops,
 109                              const struct nfs_pgio_completion_ops *compl_ops,
 110                              const struct nfs_rw_ops *rw_ops,
 111                              size_t bsize,
 112                              int how);
 113 extern  int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
 114                                    struct nfs_page *);
 115 extern  int nfs_pageio_resend(struct nfs_pageio_descriptor *,
 116                               struct nfs_pgio_header *);
 117 extern  void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
 118 extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
 119 extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
 120                                 struct nfs_page *prev,
 121                                 struct nfs_page *req);
 122 extern  int nfs_wait_on_request(struct nfs_page *);
 123 extern  void nfs_unlock_request(struct nfs_page *req);
 124 extern  void nfs_unlock_and_release_request(struct nfs_page *);
 125 extern int nfs_page_group_lock(struct nfs_page *, bool);
 126 extern void nfs_page_group_lock_wait(struct nfs_page *);
 127 extern void nfs_page_group_unlock(struct nfs_page *);
 128 extern bool nfs_page_group_sync_on_bit(struct nfs_page *, unsigned int);
 129
 130 /*
 131  * Lock the page of an asynchronous request
 132  */
 133 static inline int
 134 nfs_lock_request(struct nfs_page *req)
 135 {
 136         return !test_and_set_bit(PG_BUSY, &req->wb_flags);
 137 }
 138
 139 /**
 140  * nfs_list_add_request - Insert a request into a list
 141  * @req: request
 142  * @head: head of list into which to insert the request.
 143  */
 144 static inline void
 145 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
 146 {
 147         list_add_tail(&req->wb_list, head);
 148 }
 149
 150
 151 /**
 152  * nfs_list_remove_request - Remove a request from its wb_list
 153  * @req: request
 154  */
 155 static inline void
 156 nfs_list_remove_request(struct nfs_page *req)
 157 {
 158         if (list_empty(&req->wb_list))
 159                 return;
 160         list_del_init(&req->wb_list);
 161 }
 162
 163 static inline struct nfs_page *
 164 nfs_list_entry(struct list_head *head)
 165 {
 166         return list_entry(head, struct nfs_page, wb_list);
 167 }
 168
 169 static inline
 170 loff_t req_offset(struct nfs_page *req)
 171 {
 172         return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
 173 }
 174
 175 #endif /* _LINUX_NFS_PAGE_H */