dentry.c 2.6 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 <linux/slab.h>
  29. #include "ecryptfs_kernel.h"
  30. /**
  31. * ecryptfs_d_revalidate - revalidate an ecryptfs dentry
  32. * @dentry: The ecryptfs dentry
  33. * @flags: lookup flags
  34. *
  35. * Called when the VFS needs to revalidate a dentry. This
  36. * is called whenever a name lookup finds a dentry in the
  37. * dcache. Most filesystems leave this as NULL, because all their
  38. * dentries in the dcache are valid.
  39. *
  40. * Returns 1 if valid, 0 otherwise.
  41. *
  42. */
  43. static int ecryptfs_d_revalidate(struct dentry *dentry, unsigned int flags)
  44. {
  45. struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
  46. int rc = 1;
  47. if (flags & LOOKUP_RCU)
  48. return -ECHILD;
  49. if (lower_dentry->d_flags & DCACHE_OP_REVALIDATE)
  50. rc = lower_dentry->d_op->d_revalidate(lower_dentry, flags);
  51. if (d_really_is_positive(dentry)) {
  52. struct inode *inode = d_inode(dentry);
  53. fsstack_copy_attr_all(inode, ecryptfs_inode_to_lower(inode));
  54. if (!inode->i_nlink)
  55. return 0;
  56. }
  57. return rc;
  58. }
  59. struct kmem_cache *ecryptfs_dentry_info_cache;
  60. static void ecryptfs_dentry_free_rcu(struct rcu_head *head)
  61. {
  62. kmem_cache_free(ecryptfs_dentry_info_cache,
  63. container_of(head, struct ecryptfs_dentry_info, rcu));
  64. }
  65. /**
  66. * ecryptfs_d_release
  67. * @dentry: The ecryptfs dentry
  68. *
  69. * Called when a dentry is really deallocated.
  70. */
  71. static void ecryptfs_d_release(struct dentry *dentry)
  72. {
  73. struct ecryptfs_dentry_info *p = dentry->d_fsdata;
  74. if (p) {
  75. path_put(&p->lower_path);
  76. call_rcu(&p->rcu, ecryptfs_dentry_free_rcu);
  77. }
  78. }
  79. const struct dentry_operations ecryptfs_dops = {
  80. .d_revalidate = ecryptfs_d_revalidate,
  81. .d_release = ecryptfs_d_release,
  82. };