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