super.c 5.3 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. * Michael C. Thompson <mcthomps@us.ibm.com>
  9. *
  10. * This program is free software; you can redistribute it and/or
  11. * modify it under the terms of the GNU General Public License as
  12. * published by the Free Software Foundation; either version 2 of the
  13. * License, or (at your option) any later version.
  14. *
  15. * This program is distributed in the hope that it will be useful, but
  16. * WITHOUT ANY WARRANTY; without even the implied warranty of
  17. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18. * General Public License for more details.
  19. *
  20. * You should have received a copy of the GNU General Public License
  21. * along with this program; if not, write to the Free Software
  22. * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  23. * 02111-1307, USA.
  24. */
  25. #include <linux/fs.h>
  26. #include <linux/mount.h>
  27. #include <linux/key.h>
  28. #include <linux/seq_file.h>
  29. #include <linux/crypto.h>
  30. #include "ecryptfs_kernel.h"
  31. struct kmem_cache *ecryptfs_inode_info_cache;
  32. /**
  33. * ecryptfs_alloc_inode - allocate an ecryptfs inode
  34. * @sb: Pointer to the ecryptfs super block
  35. *
  36. * Called to bring an inode into existence.
  37. *
  38. * Only handle allocation, setting up structures should be done in
  39. * ecryptfs_read_inode. This is because the kernel, between now and
  40. * then, will 0 out the private data pointer.
  41. *
  42. * Returns a pointer to a newly allocated inode, NULL otherwise
  43. */
  44. static struct inode *ecryptfs_alloc_inode(struct super_block *sb)
  45. {
  46. struct ecryptfs_inode_info *ecryptfs_inode;
  47. struct inode *inode = NULL;
  48. ecryptfs_inode = kmem_cache_alloc(ecryptfs_inode_info_cache,
  49. GFP_KERNEL);
  50. if (unlikely(!ecryptfs_inode))
  51. goto out;
  52. ecryptfs_init_crypt_stat(&ecryptfs_inode->crypt_stat);
  53. inode = &ecryptfs_inode->vfs_inode;
  54. out:
  55. return inode;
  56. }
  57. /**
  58. * ecryptfs_destroy_inode
  59. * @inode: The ecryptfs inode
  60. *
  61. * This is used during the final destruction of the inode.
  62. * All allocation of memory related to the inode, including allocated
  63. * memory in the crypt_stat struct, will be released here.
  64. * There should be no chance that this deallocation will be missed.
  65. */
  66. static void ecryptfs_destroy_inode(struct inode *inode)
  67. {
  68. struct ecryptfs_inode_info *inode_info;
  69. inode_info = ecryptfs_inode_to_private(inode);
  70. ecryptfs_destruct_crypt_stat(&inode_info->crypt_stat);
  71. kmem_cache_free(ecryptfs_inode_info_cache, inode_info);
  72. }
  73. /**
  74. * ecryptfs_init_inode
  75. * @inode: The ecryptfs inode
  76. *
  77. * Set up the ecryptfs inode.
  78. */
  79. void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode)
  80. {
  81. ecryptfs_set_inode_lower(inode, lower_inode);
  82. inode->i_ino = lower_inode->i_ino;
  83. inode->i_version++;
  84. inode->i_op = &ecryptfs_main_iops;
  85. inode->i_fop = &ecryptfs_main_fops;
  86. inode->i_mapping->a_ops = &ecryptfs_aops;
  87. }
  88. /**
  89. * ecryptfs_put_super
  90. * @sb: Pointer to the ecryptfs super block
  91. *
  92. * Final actions when unmounting a file system.
  93. * This will handle deallocation and release of our private data.
  94. */
  95. static void ecryptfs_put_super(struct super_block *sb)
  96. {
  97. struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
  98. ecryptfs_destruct_mount_crypt_stat(&sb_info->mount_crypt_stat);
  99. kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
  100. ecryptfs_set_superblock_private(sb, NULL);
  101. }
  102. /**
  103. * ecryptfs_statfs
  104. * @sb: The ecryptfs super block
  105. * @buf: The struct kstatfs to fill in with stats
  106. *
  107. * Get the filesystem statistics. Currently, we let this pass right through
  108. * to the lower filesystem and take no action ourselves.
  109. */
  110. static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf)
  111. {
  112. return vfs_statfs(ecryptfs_dentry_to_lower(dentry), buf);
  113. }
  114. /**
  115. * ecryptfs_clear_inode
  116. * @inode - The ecryptfs inode
  117. *
  118. * Called by iput() when the inode reference count reached zero
  119. * and the inode is not hashed anywhere. Used to clear anything
  120. * that needs to be, before the inode is completely destroyed and put
  121. * on the inode free list. We use this to drop out reference to the
  122. * lower inode.
  123. */
  124. static void ecryptfs_clear_inode(struct inode *inode)
  125. {
  126. iput(ecryptfs_inode_to_lower(inode));
  127. }
  128. /**
  129. * ecryptfs_show_options
  130. *
  131. * Prints the directory we are currently mounted over.
  132. * Returns zero on success; non-zero otherwise
  133. */
  134. static int ecryptfs_show_options(struct seq_file *m, struct vfsmount *mnt)
  135. {
  136. struct super_block *sb = mnt->mnt_sb;
  137. struct dentry *lower_root_dentry = ecryptfs_dentry_to_lower(sb->s_root);
  138. struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(sb->s_root);
  139. char *tmp_page;
  140. char *path;
  141. int rc = 0;
  142. tmp_page = (char *)__get_free_page(GFP_KERNEL);
  143. if (!tmp_page) {
  144. rc = -ENOMEM;
  145. goto out;
  146. }
  147. path = d_path(lower_root_dentry, lower_mnt, tmp_page, PAGE_SIZE);
  148. if (IS_ERR(path)) {
  149. rc = PTR_ERR(path);
  150. goto out;
  151. }
  152. seq_printf(m, ",dir=%s", path);
  153. free_page((unsigned long)tmp_page);
  154. out:
  155. return rc;
  156. }
  157. const struct super_operations ecryptfs_sops = {
  158. .alloc_inode = ecryptfs_alloc_inode,
  159. .destroy_inode = ecryptfs_destroy_inode,
  160. .drop_inode = generic_delete_inode,
  161. .put_super = ecryptfs_put_super,
  162. .statfs = ecryptfs_statfs,
  163. .remount_fs = NULL,
  164. .clear_inode = ecryptfs_clear_inode,
  165. .show_options = ecryptfs_show_options
  166. };