vxfs_subr.c 4.5 KB

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  1. /*
  2. * Copyright (c) 2000-2001 Christoph Hellwig.
  3. * All rights reserved.
  4. *
  5. * Redistribution and use in source and binary forms, with or without
  6. * modification, are permitted provided that the following conditions
  7. * are met:
  8. * 1. Redistributions of source code must retain the above copyright
  9. * notice, this list of conditions, and the following disclaimer,
  10. * without modification.
  11. * 2. The name of the author may not be used to endorse or promote products
  12. * derived from this software without specific prior written permission.
  13. *
  14. * Alternatively, this software may be distributed under the terms of the
  15. * GNU General Public License ("GPL").
  16. *
  17. * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18. * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20. * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
  21. * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22. * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23. * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24. * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26. * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27. * SUCH DAMAGE.
  28. */
  29. /*
  30. * Veritas filesystem driver - shared subroutines.
  31. */
  32. #include <linux/fs.h>
  33. #include <linux/buffer_head.h>
  34. #include <linux/kernel.h>
  35. #include <linux/pagemap.h>
  36. #include "vxfs_extern.h"
  37. static int vxfs_readpage(struct file *, struct page *);
  38. static sector_t vxfs_bmap(struct address_space *, sector_t);
  39. const struct address_space_operations vxfs_aops = {
  40. .readpage = vxfs_readpage,
  41. .bmap = vxfs_bmap,
  42. };
  43. inline void
  44. vxfs_put_page(struct page *pp)
  45. {
  46. kunmap(pp);
  47. put_page(pp);
  48. }
  49. /**
  50. * vxfs_get_page - read a page into memory.
  51. * @ip: inode to read from
  52. * @n: page number
  53. *
  54. * Description:
  55. * vxfs_get_page reads the @n th page of @ip into the pagecache.
  56. *
  57. * Returns:
  58. * The wanted page on success, else a NULL pointer.
  59. */
  60. struct page *
  61. vxfs_get_page(struct address_space *mapping, u_long n)
  62. {
  63. struct page * pp;
  64. pp = read_mapping_page(mapping, n, NULL);
  65. if (!IS_ERR(pp)) {
  66. kmap(pp);
  67. /** if (!PageChecked(pp)) **/
  68. /** vxfs_check_page(pp); **/
  69. if (PageError(pp))
  70. goto fail;
  71. }
  72. return (pp);
  73. fail:
  74. vxfs_put_page(pp);
  75. return ERR_PTR(-EIO);
  76. }
  77. /**
  78. * vxfs_bread - read buffer for a give inode,block tuple
  79. * @ip: inode
  80. * @block: logical block
  81. *
  82. * Description:
  83. * The vxfs_bread function reads block no @block of
  84. * @ip into the buffercache.
  85. *
  86. * Returns:
  87. * The resulting &struct buffer_head.
  88. */
  89. struct buffer_head *
  90. vxfs_bread(struct inode *ip, int block)
  91. {
  92. struct buffer_head *bp;
  93. daddr_t pblock;
  94. pblock = vxfs_bmap1(ip, block);
  95. bp = sb_bread(ip->i_sb, pblock);
  96. return (bp);
  97. }
  98. /**
  99. * vxfs_get_block - locate buffer for given inode,block tuple
  100. * @ip: inode
  101. * @iblock: logical block
  102. * @bp: buffer skeleton
  103. * @create: %TRUE if blocks may be newly allocated.
  104. *
  105. * Description:
  106. * The vxfs_get_block function fills @bp with the right physical
  107. * block and device number to perform a lowlevel read/write on
  108. * it.
  109. *
  110. * Returns:
  111. * Zero on success, else a negativ error code (-EIO).
  112. */
  113. static int
  114. vxfs_getblk(struct inode *ip, sector_t iblock,
  115. struct buffer_head *bp, int create)
  116. {
  117. daddr_t pblock;
  118. pblock = vxfs_bmap1(ip, iblock);
  119. if (pblock != 0) {
  120. map_bh(bp, ip->i_sb, pblock);
  121. return 0;
  122. }
  123. return -EIO;
  124. }
  125. /**
  126. * vxfs_readpage - read one page synchronously into the pagecache
  127. * @file: file context (unused)
  128. * @page: page frame to fill in.
  129. *
  130. * Description:
  131. * The vxfs_readpage routine reads @page synchronously into the
  132. * pagecache.
  133. *
  134. * Returns:
  135. * Zero on success, else a negative error code.
  136. *
  137. * Locking status:
  138. * @page is locked and will be unlocked.
  139. */
  140. static int
  141. vxfs_readpage(struct file *file, struct page *page)
  142. {
  143. return block_read_full_page(page, vxfs_getblk);
  144. }
  145. /**
  146. * vxfs_bmap - perform logical to physical block mapping
  147. * @mapping: logical to physical mapping to use
  148. * @block: logical block (relative to @mapping).
  149. *
  150. * Description:
  151. * Vxfs_bmap find out the corresponding phsical block to the
  152. * @mapping, @block pair.
  153. *
  154. * Returns:
  155. * Physical block number on success, else Zero.
  156. *
  157. * Locking status:
  158. * We are under the bkl.
  159. */
  160. static sector_t
  161. vxfs_bmap(struct address_space *mapping, sector_t block)
  162. {
  163. return generic_block_bmap(mapping, block, vxfs_getblk);
  164. }