nfs_page.h 3.4 KB

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  1. /*
  2. * linux/include/linux/nfs_page.h
  3. *
  4. * Copyright (C) 2000 Trond Myklebust
  5. *
  6. * NFS page cache wrapper.
  7. */
  8. #ifndef _LINUX_NFS_PAGE_H
  9. #define _LINUX_NFS_PAGE_H
  10. #include <linux/list.h>
  11. #include <linux/pagemap.h>
  12. #include <linux/wait.h>
  13. #include <linux/sunrpc/auth.h>
  14. #include <linux/nfs_xdr.h>
  15. #include <asm/atomic.h>
  16. /*
  17. * Valid flags for the radix tree
  18. */
  19. #define NFS_PAGE_TAG_DIRTY 0
  20. #define NFS_PAGE_TAG_WRITEBACK 1
  21. /*
  22. * Valid flags for a dirty buffer
  23. */
  24. #define PG_BUSY 0
  25. #define PG_NEED_COMMIT 1
  26. #define PG_NEED_RESCHED 2
  27. #define PG_NEED_FLUSH 3
  28. struct nfs_inode;
  29. struct nfs_page {
  30. struct list_head wb_list, /* Defines state of page: */
  31. *wb_list_head; /* read/write/commit */
  32. struct page *wb_page; /* page to read in/write out */
  33. struct nfs_open_context *wb_context; /* File state context info */
  34. atomic_t wb_complete; /* i/os we're waiting for */
  35. unsigned long wb_index; /* Offset >> PAGE_CACHE_SHIFT */
  36. unsigned int wb_offset, /* Offset & ~PAGE_CACHE_MASK */
  37. wb_pgbase, /* Start of page data */
  38. wb_bytes; /* Length of request */
  39. atomic_t wb_count; /* reference count */
  40. unsigned long wb_flags;
  41. struct nfs_writeverf wb_verf; /* Commit cookie */
  42. };
  43. #define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags))
  44. extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
  45. struct inode *inode,
  46. struct page *page,
  47. unsigned int offset,
  48. unsigned int count);
  49. extern void nfs_clear_request(struct nfs_page *req);
  50. extern void nfs_release_request(struct nfs_page *req);
  51. extern long nfs_scan_dirty(struct address_space *mapping,
  52. struct writeback_control *wbc,
  53. struct list_head *dst);
  54. extern int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *head, struct list_head *dst,
  55. unsigned long idx_start, unsigned int npages);
  56. extern int nfs_coalesce_requests(struct list_head *, struct list_head *,
  57. unsigned int);
  58. extern int nfs_wait_on_request(struct nfs_page *);
  59. extern void nfs_unlock_request(struct nfs_page *req);
  60. extern int nfs_set_page_writeback_locked(struct nfs_page *req);
  61. extern void nfs_clear_page_writeback(struct nfs_page *req);
  62. /*
  63. * Lock the page of an asynchronous request without incrementing the wb_count
  64. */
  65. static inline int
  66. nfs_lock_request_dontget(struct nfs_page *req)
  67. {
  68. return !test_and_set_bit(PG_BUSY, &req->wb_flags);
  69. }
  70. /*
  71. * Lock the page of an asynchronous request
  72. */
  73. static inline int
  74. nfs_lock_request(struct nfs_page *req)
  75. {
  76. if (test_and_set_bit(PG_BUSY, &req->wb_flags))
  77. return 0;
  78. atomic_inc(&req->wb_count);
  79. return 1;
  80. }
  81. /**
  82. * nfs_list_add_request - Insert a request into a list
  83. * @req: request
  84. * @head: head of list into which to insert the request.
  85. */
  86. static inline void
  87. nfs_list_add_request(struct nfs_page *req, struct list_head *head)
  88. {
  89. list_add_tail(&req->wb_list, head);
  90. req->wb_list_head = head;
  91. }
  92. /**
  93. * nfs_list_remove_request - Remove a request from its wb_list
  94. * @req: request
  95. */
  96. static inline void
  97. nfs_list_remove_request(struct nfs_page *req)
  98. {
  99. if (list_empty(&req->wb_list))
  100. return;
  101. list_del_init(&req->wb_list);
  102. req->wb_list_head = NULL;
  103. }
  104. static inline struct nfs_page *
  105. nfs_list_entry(struct list_head *head)
  106. {
  107. return list_entry(head, struct nfs_page, wb_list);
  108. }
  109. static inline
  110. loff_t req_offset(struct nfs_page *req)
  111. {
  112. return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
  113. }
  114. #endif /* _LINUX_NFS_PAGE_H */