dentry.c 2.8 KB

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  1. /**
  2. * eCryptfs: Linux filesystem encryption layer
  3. *
  4. * Copyright (C) 1997-2003 Erez Zadok
  5. * Copyright (C) 2001-2003 Stony Brook University
  6. * Copyright (C) 2004-2006 International Business Machines Corp.
  7. * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  8. *
  9. * This program is free software; you can redistribute it and/or
  10. * modify it under the terms of the GNU General Public License as
  11. * published by the Free Software Foundation; either version 2 of the
  12. * License, or (at your option) any later version.
  13. *
  14. * This program is distributed in the hope that it will be useful, but
  15. * WITHOUT ANY WARRANTY; without even the implied warranty of
  16. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  17. * General Public License for more details.
  18. *
  19. * You should have received a copy of the GNU General Public License
  20. * along with this program; if not, write to the Free Software
  21. * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  22. * 02111-1307, USA.
  23. */
  24. #include <linux/dcache.h>
  25. #include <linux/namei.h>
  26. #include <linux/mount.h>
  27. #include <linux/fs_stack.h>
  28. #include "ecryptfs_kernel.h"
  29. /**
  30. * ecryptfs_d_revalidate - revalidate an ecryptfs dentry
  31. * @dentry: The ecryptfs dentry
  32. * @nd: The associated nameidata
  33. *
  34. * Called when the VFS needs to revalidate a dentry. This
  35. * is called whenever a name lookup finds a dentry in the
  36. * dcache. Most filesystems leave this as NULL, because all their
  37. * dentries in the dcache are valid.
  38. *
  39. * Returns 1 if valid, 0 otherwise.
  40. *
  41. */
  42. static int ecryptfs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
  43. {
  44. struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
  45. struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
  46. struct dentry *dentry_save;
  47. struct vfsmount *vfsmount_save;
  48. int rc = 1;
  49. if (!lower_dentry->d_op || !lower_dentry->d_op->d_revalidate)
  50. goto out;
  51. dentry_save = nd->dentry;
  52. vfsmount_save = nd->mnt;
  53. nd->dentry = lower_dentry;
  54. nd->mnt = lower_mnt;
  55. rc = lower_dentry->d_op->d_revalidate(lower_dentry, nd);
  56. nd->dentry = dentry_save;
  57. nd->mnt = vfsmount_save;
  58. if (dentry->d_inode) {
  59. struct inode *lower_inode =
  60. ecryptfs_inode_to_lower(dentry->d_inode);
  61. fsstack_copy_attr_all(dentry->d_inode, lower_inode, NULL);
  62. }
  63. out:
  64. return rc;
  65. }
  66. struct kmem_cache *ecryptfs_dentry_info_cache;
  67. /**
  68. * ecryptfs_d_release
  69. * @dentry: The ecryptfs dentry
  70. *
  71. * Called when a dentry is really deallocated.
  72. */
  73. static void ecryptfs_d_release(struct dentry *dentry)
  74. {
  75. if (ecryptfs_dentry_to_private(dentry)) {
  76. if (ecryptfs_dentry_to_lower(dentry)) {
  77. mntput(ecryptfs_dentry_to_lower_mnt(dentry));
  78. dput(ecryptfs_dentry_to_lower(dentry));
  79. }
  80. kmem_cache_free(ecryptfs_dentry_info_cache,
  81. ecryptfs_dentry_to_private(dentry));
  82. }
  83. return;
  84. }
  85. struct dentry_operations ecryptfs_dops = {
  86. .d_revalidate = ecryptfs_d_revalidate,
  87. .d_release = ecryptfs_d_release,
  88. };