LXR linux/include/linux/nfs

   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 */
  24enum {
  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
  38struct nfs_inode;
  39struct 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
  55struct nfs_pageio_descriptor;
  56struct 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
  66struct 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
  78struct 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
  87struct 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
 113extern  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);
 118extern  void nfs_release_request(struct nfs_page *);
 119
 120
 121extern  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);
 128extern  int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
 129                                   struct nfs_page *);
 130extern  int nfs_pageio_resend(struct nfs_pageio_descriptor *,
 131                              struct nfs_pgio_header *);
 132extern  void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
 133extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
 134extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
 135                                struct nfs_page *prev,
 136                                struct nfs_page *req);
 137extern  int nfs_wait_on_request(struct nfs_page *);
 138extern  void nfs_unlock_request(struct nfs_page *req);
 139extern  void nfs_unlock_and_release_request(struct nfs_page *);
 140extern int nfs_page_group_lock(struct nfs_page *, bool);
 141extern void nfs_page_group_lock_wait(struct nfs_page *);
 142extern void nfs_page_group_unlock(struct nfs_page *);
 143extern bool nfs_page_group_sync_on_bit(struct nfs_page *, unsigned int);
 144
 145/*
 146 * Lock the page of an asynchronous request
 147 */
 148static inline int
 149nfs_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 */
 159static inline void
 160nfs_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 */
 170static inline void
 171nfs_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
 178static inline struct nfs_page *
 179nfs_list_entry(struct list_head *head)
 180{
 181        return list_entry(head, struct nfs_page, wb_list);
 182}
 183
 184static inline
 185loff_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 */
 191