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 <asm/atomic.h>
  20
  21 /*
  22  * Valid flags for the radix tree
  23  */
  24 #define NFS_PAGE_TAG_DIRTY      0
  25 #define NFS_PAGE_TAG_WRITEBACK  1
  26
  27 /*
  28  * Valid flags for a dirty buffer
  29  */
  30 #define PG_BUSY                 0
  31 #define PG_NEED_COMMIT          1
  32 #define PG_NEED_RESCHED         2
  33
  34 struct nfs_inode;
  35 struct nfs_page {
  36         struct list_head        wb_list,        /* Defines state of page: */
  37                                 *wb_list_head;  /*      read/write/commit */
  38         struct page             *wb_page;       /* page to read in/write out */
  39         struct nfs_open_context *wb_context;    /* File state context info */
  40         atomic_t                wb_complete;    /* i/os we're waiting for */
  41         unsigned long           wb_index;       /* Offset >> PAGE_CACHE_SHIFT */
  42         unsigned int            wb_offset,      /* Offset & ~PAGE_CACHE_MASK */
  43                                 wb_pgbase,      /* Start of page data */
  44                                 wb_bytes;       /* Length of request */
  45         atomic_t                wb_count;       /* reference count */
  46         unsigned long           wb_flags;
  47         struct nfs_writeverf    wb_verf;        /* Commit cookie */
  48 };
  49
  50 #define NFS_WBACK_BUSY(req)     (test_bit(PG_BUSY,&(req)->wb_flags))
  51 #define NFS_NEED_COMMIT(req)    (test_bit(PG_NEED_COMMIT,&(req)->wb_flags))
  52 #define NFS_NEED_RESCHED(req)   (test_bit(PG_NEED_RESCHED,&(req)->wb_flags))
  53
  54 extern  struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
  55                                             struct inode *inode,
  56                                             struct page *page,
  57                                             unsigned int offset,
  58                                             unsigned int count);
  59 extern  void nfs_clear_request(struct nfs_page *req);
  60 extern  void nfs_release_request(struct nfs_page *req);
  61
  62
  63 extern  int nfs_scan_lock_dirty(struct nfs_inode *nfsi, struct list_head *dst,
  64                                 unsigned long idx_start, unsigned int npages);
  65 extern  int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *head, struct list_head *dst,
  66                           unsigned long idx_start, unsigned int npages);
  67 extern  int nfs_coalesce_requests(struct list_head *, struct list_head *,
  68                                   unsigned int);
  69 extern  int nfs_wait_on_request(struct nfs_page *);
  70 extern  void nfs_unlock_request(struct nfs_page *req);
  71 extern  int nfs_set_page_writeback_locked(struct nfs_page *req);
  72 extern  void nfs_clear_page_writeback(struct nfs_page *req);
  73
  74
  75 /*
  76  * Lock the page of an asynchronous request without incrementing the wb_count
  77  */
  78 static inline int
  79 nfs_lock_request_dontget(struct nfs_page *req)
  80 {
  81         return !test_and_set_bit(PG_BUSY, &req->wb_flags);
  82 }
  83
  84 /*
  85  * Lock the page of an asynchronous request
  86  */
  87 static inline int
  88 nfs_lock_request(struct nfs_page *req)
  89 {
  90         if (test_and_set_bit(PG_BUSY, &req->wb_flags))
  91                 return 0;
  92         atomic_inc(&req->wb_count);
  93         return 1;
  94 }
  95
  96 /**
  97  * nfs_list_add_request - Insert a request into a list
  98  * @req: request
  99  * @head: head of list into which to insert the request.
 100  */
 101 static inline void
 102 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
 103 {
 104         list_add_tail(&req->wb_list, head);
 105         req->wb_list_head = head;
 106 }
 107
 108
 109 /**
 110  * nfs_list_remove_request - Remove a request from its wb_list
 111  * @req: request
 112  */
 113 static inline void
 114 nfs_list_remove_request(struct nfs_page *req)
 115 {
 116         if (list_empty(&req->wb_list))
 117                 return;
 118         list_del_init(&req->wb_list);
 119         req->wb_list_head = NULL;
 120 }
 121
 122 static inline int
 123 nfs_defer_commit(struct nfs_page *req)
 124 {
 125         return !test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags);
 126 }
 127
 128 static inline void
 129 nfs_clear_commit(struct nfs_page *req)
 130 {
 131         smp_mb__before_clear_bit();
 132         clear_bit(PG_NEED_COMMIT, &req->wb_flags);
 133         smp_mb__after_clear_bit();
 134 }
 135
 136 static inline int
 137 nfs_defer_reschedule(struct nfs_page *req)
 138 {
 139         return !test_and_set_bit(PG_NEED_RESCHED, &req->wb_flags);
 140 }
 141
 142 static inline void
 143 nfs_clear_reschedule(struct nfs_page *req)
 144 {
 145         smp_mb__before_clear_bit();
 146         clear_bit(PG_NEED_RESCHED, &req->wb_flags);
 147         smp_mb__after_clear_bit();
 148 }
 149
 150 static inline struct nfs_page *
 151 nfs_list_entry(struct list_head *head)
 152 {
 153         return list_entry(head, struct nfs_page, wb_list);
 154 }
 155
 156 static inline
 157 loff_t req_offset(struct nfs_page *req)
 158 {
 159         return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
 160 }
 161
 162 #endif /* _LINUX_NFS_PAGE_H */