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_SHIFT */
  45         unsigned int            wb_offset,      /* Offset & ~PAGE_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         unsigned int    (*pg_get_mirror_count)(struct nfs_pageio_descriptor *,
  62                                        struct nfs_page *);
  63         void    (*pg_cleanup)(struct nfs_pageio_descriptor *);
  64 };
  65
  66 struct nfs_rw_ops {
  67         const fmode_t rw_mode;
  68         struct nfs_pgio_header *(*rw_alloc_header)(void);
  69         void (*rw_free_header)(struct nfs_pgio_header *);
  70         int  (*rw_done)(struct rpc_task *, struct nfs_pgio_header *,
  71                         struct inode *);
  72         void (*rw_result)(struct rpc_task *, struct nfs_pgio_header *);
  73         void (*rw_initiate)(struct nfs_pgio_header *, struct rpc_message *,
  74                             const struct nfs_rpc_ops *,
  75                             struct rpc_task_setup *, int);
  76 };
  77
  78 struct nfs_pgio_mirror {
  79         struct list_head        pg_list;
  80         unsigned long           pg_bytes_written;
  81         size_t                  pg_count;
  82         size_t                  pg_bsize;
  83         unsigned int            pg_base;
  84         unsigned char           pg_recoalesce : 1;
  85 };
  86
  87 struct nfs_pageio_descriptor {
  88         unsigned char           pg_moreio : 1;
  89         struct inode            *pg_inode;
  90         const struct nfs_pageio_ops *pg_ops;
  91         const struct nfs_rw_ops *pg_rw_ops;
  92         int                     pg_ioflags;
  93         int                     pg_error;
  94         const struct rpc_call_ops *pg_rpc_callops;
  95         const struct nfs_pgio_completion_ops *pg_completion_ops;
  96         struct pnfs_layout_segment *pg_lseg;
  97         struct nfs_direct_req   *pg_dreq;
  98         void                    *pg_layout_private;
  99         unsigned int            pg_bsize;       /* default bsize for mirrors */
 100
 101         u32                     pg_mirror_count;
 102         struct nfs_pgio_mirror  *pg_mirrors;
 103         struct nfs_pgio_mirror  pg_mirrors_static[1];
 104         struct nfs_pgio_mirror  *pg_mirrors_dynamic;
 105         u32                     pg_mirror_idx;  /* current mirror */
 106 };
 107
 108 /* arbitrarily selected limit to number of mirrors */
 109 #define NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX 16
 110
 111 #define NFS_WBACK_BUSY(req)     (test_bit(PG_BUSY,&(req)->wb_flags))
 112
 113 extern  struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
 114                                             struct page *page,
 115                                             struct nfs_page *last,
 116                                             unsigned int offset,
 117                                             unsigned int count);
 118 extern  void nfs_release_request(struct nfs_page *);
 119
 120
 121 extern  void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
 122                              struct inode *inode,
 123                              const struct nfs_pageio_ops *pg_ops,
 124                              const struct nfs_pgio_completion_ops *compl_ops,
 125                              const struct nfs_rw_ops *rw_ops,
 126                              size_t bsize,
 127                              int how);
 128 extern  int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
 129                                    struct nfs_page *);
 130 extern  int nfs_pageio_resend(struct nfs_pageio_descriptor *,
 131                               struct nfs_pgio_header *);
 132 extern  void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
 133 extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
 134 extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
 135                                 struct nfs_page *prev,
 136                                 struct nfs_page *req);
 137 extern  int nfs_wait_on_request(struct nfs_page *);
 138 extern  void nfs_unlock_request(struct nfs_page *req);
 139 extern  void nfs_unlock_and_release_request(struct nfs_page *);
 140 extern int nfs_page_group_lock(struct nfs_page *, bool);
 141 extern void nfs_page_group_lock_wait(struct nfs_page *);
 142 extern void nfs_page_group_unlock(struct nfs_page *);
 143 extern bool nfs_page_group_sync_on_bit(struct nfs_page *, unsigned int);
 144
 145 /*
 146  * Lock the page of an asynchronous request
 147  */
 148 static inline int
 149 nfs_lock_request(struct nfs_page *req)
 150 {
 151         return !test_and_set_bit(PG_BUSY, &req->wb_flags);
 152 }
 153
 154 /**
 155  * nfs_list_add_request - Insert a request into a list
 156  * @req: request
 157  * @head: head of list into which to insert the request.
 158  */
 159 static inline void
 160 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
 161 {
 162         list_add_tail(&req->wb_list, head);
 163 }
 164
 165
 166 /**
 167  * nfs_list_remove_request - Remove a request from its wb_list
 168  * @req: request
 169  */
 170 static inline void
 171 nfs_list_remove_request(struct nfs_page *req)
 172 {
 173         if (list_empty(&req->wb_list))
 174                 return;
 175         list_del_init(&req->wb_list);
 176 }
 177
 178 static inline struct nfs_page *
 179 nfs_list_entry(struct list_head *head)
 180 {
 181         return list_entry(head, struct nfs_page, wb_list);
 182 }
 183
 184 static inline
 185 loff_t req_offset(struct nfs_page *req)
 186 {
 187         return (((loff_t)req->wb_index) << PAGE_SHIFT) + req->wb_offset;
 188 }
 189
 190 #endif /* _LINUX_NFS_PAGE_H */