vxfs_subr.c 4.6 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/slab.h>
  36. #include <linux/pagemap.h>
  37. #include "vxfs_extern.h"
  38. static int vxfs_readpage(struct file *, struct page *);
  39. static sector_t vxfs_bmap(struct address_space *, sector_t);
  40. const struct address_space_operations vxfs_aops = {
  41. .readpage = vxfs_readpage,
  42. .bmap = vxfs_bmap,
  43. .sync_page = block_sync_page,
  44. };
  45. inline void
  46. vxfs_put_page(struct page *pp)
  47. {
  48. kunmap(pp);
  49. page_cache_release(pp);
  50. }
  51. /**
  52. * vxfs_get_page - read a page into memory.
  53. * @ip: inode to read from
  54. * @n: page number
  55. *
  56. * Description:
  57. * vxfs_get_page reads the @n th page of @ip into the pagecache.
  58. *
  59. * Returns:
  60. * The wanted page on success, else a NULL pointer.
  61. */
  62. struct page *
  63. vxfs_get_page(struct address_space *mapping, u_long n)
  64. {
  65. struct page * pp;
  66. pp = read_mapping_page(mapping, n, NULL);
  67. if (!IS_ERR(pp)) {
  68. kmap(pp);
  69. /** if (!PageChecked(pp)) **/
  70. /** vxfs_check_page(pp); **/
  71. if (PageError(pp))
  72. goto fail;
  73. }
  74. return (pp);
  75. fail:
  76. vxfs_put_page(pp);
  77. return ERR_PTR(-EIO);
  78. }
  79. /**
  80. * vxfs_bread - read buffer for a give inode,block tuple
  81. * @ip: inode
  82. * @block: logical block
  83. *
  84. * Description:
  85. * The vxfs_bread function reads block no @block of
  86. * @ip into the buffercache.
  87. *
  88. * Returns:
  89. * The resulting &struct buffer_head.
  90. */
  91. struct buffer_head *
  92. vxfs_bread(struct inode *ip, int block)
  93. {
  94. struct buffer_head *bp;
  95. daddr_t pblock;
  96. pblock = vxfs_bmap1(ip, block);
  97. bp = sb_bread(ip->i_sb, pblock);
  98. return (bp);
  99. }
  100. /**
  101. * vxfs_get_block - locate buffer for given inode,block tuple
  102. * @ip: inode
  103. * @iblock: logical block
  104. * @bp: buffer skeleton
  105. * @create: %TRUE if blocks may be newly allocated.
  106. *
  107. * Description:
  108. * The vxfs_get_block function fills @bp with the right physical
  109. * block and device number to perform a lowlevel read/write on
  110. * it.
  111. *
  112. * Returns:
  113. * Zero on success, else a negativ error code (-EIO).
  114. */
  115. static int
  116. vxfs_getblk(struct inode *ip, sector_t iblock,
  117. struct buffer_head *bp, int create)
  118. {
  119. daddr_t pblock;
  120. pblock = vxfs_bmap1(ip, iblock);
  121. if (pblock != 0) {
  122. map_bh(bp, ip->i_sb, pblock);
  123. return 0;
  124. }
  125. return -EIO;
  126. }
  127. /**
  128. * vxfs_readpage - read one page synchronously into the pagecache
  129. * @file: file context (unused)
  130. * @page: page frame to fill in.
  131. *
  132. * Description:
  133. * The vxfs_readpage routine reads @page synchronously into the
  134. * pagecache.
  135. *
  136. * Returns:
  137. * Zero on success, else a negative error code.
  138. *
  139. * Locking status:
  140. * @page is locked and will be unlocked.
  141. */
  142. static int
  143. vxfs_readpage(struct file *file, struct page *page)
  144. {
  145. return block_read_full_page(page, vxfs_getblk);
  146. }
  147. /**
  148. * vxfs_bmap - perform logical to physical block mapping
  149. * @mapping: logical to physical mapping to use
  150. * @block: logical block (relative to @mapping).
  151. *
  152. * Description:
  153. * Vxfs_bmap find out the corresponding phsical block to the
  154. * @mapping, @block pair.
  155. *
  156. * Returns:
  157. * Physical block number on success, else Zero.
  158. *
  159. * Locking status:
  160. * We are under the bkl.
  161. */
  162. static sector_t
  163. vxfs_bmap(struct address_space *mapping, sector_t block)
  164. {
  165. return generic_block_bmap(mapping, block, vxfs_getblk);
  166. }