mount.c 4.6 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177
  1. /* -*- mode: c; c-basic-offset: 8; -*-
  2. * vim: noexpandtab sw=8 ts=8 sts=0:
  3. *
  4. * mount.c - operations for initializing and mounting configfs.
  5. *
  6. * This program is free software; you can redistribute it and/or
  7. * modify it under the terms of the GNU General Public
  8. * License as published by the Free Software Foundation; either
  9. * version 2 of the License, or (at your option) any later version.
  10. *
  11. * This program is distributed in the hope that it will be useful,
  12. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14. * General Public License for more details.
  15. *
  16. * You should have received a copy of the GNU General Public
  17. * License along with this program; if not, write to the
  18. * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19. * Boston, MA 021110-1307, USA.
  20. *
  21. * Based on sysfs:
  22. * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
  23. *
  24. * configfs Copyright (C) 2005 Oracle. All rights reserved.
  25. */
  26. #include <linux/fs.h>
  27. #include <linux/module.h>
  28. #include <linux/mount.h>
  29. #include <linux/pagemap.h>
  30. #include <linux/init.h>
  31. #include <linux/configfs.h>
  32. #include "configfs_internal.h"
  33. /* Random magic number */
  34. #define CONFIGFS_MAGIC 0x62656570
  35. struct vfsmount * configfs_mount = NULL;
  36. struct super_block * configfs_sb = NULL;
  37. struct kmem_cache *configfs_dir_cachep;
  38. static int configfs_mnt_count = 0;
  39. static const struct super_operations configfs_ops = {
  40. .statfs = simple_statfs,
  41. .drop_inode = generic_delete_inode,
  42. };
  43. static struct config_group configfs_root_group = {
  44. .cg_item = {
  45. .ci_namebuf = "root",
  46. .ci_name = configfs_root_group.cg_item.ci_namebuf,
  47. },
  48. };
  49. int configfs_is_root(struct config_item *item)
  50. {
  51. return item == &configfs_root_group.cg_item;
  52. }
  53. static struct configfs_dirent configfs_root = {
  54. .s_sibling = LIST_HEAD_INIT(configfs_root.s_sibling),
  55. .s_children = LIST_HEAD_INIT(configfs_root.s_children),
  56. .s_element = &configfs_root_group.cg_item,
  57. .s_type = CONFIGFS_ROOT,
  58. .s_iattr = NULL,
  59. };
  60. static int configfs_fill_super(struct super_block *sb, void *data, int silent)
  61. {
  62. struct inode *inode;
  63. struct dentry *root;
  64. sb->s_blocksize = PAGE_CACHE_SIZE;
  65. sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
  66. sb->s_magic = CONFIGFS_MAGIC;
  67. sb->s_op = &configfs_ops;
  68. sb->s_time_gran = 1;
  69. configfs_sb = sb;
  70. inode = configfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
  71. &configfs_root);
  72. if (inode) {
  73. inode->i_op = &configfs_dir_inode_operations;
  74. inode->i_fop = &configfs_dir_operations;
  75. /* directory inodes start off with i_nlink == 2 (for "." entry) */
  76. inc_nlink(inode);
  77. } else {
  78. pr_debug("configfs: could not get root inode\n");
  79. return -ENOMEM;
  80. }
  81. root = d_alloc_root(inode);
  82. if (!root) {
  83. pr_debug("%s: could not get root dentry!\n",__FUNCTION__);
  84. iput(inode);
  85. return -ENOMEM;
  86. }
  87. config_group_init(&configfs_root_group);
  88. configfs_root_group.cg_item.ci_dentry = root;
  89. root->d_fsdata = &configfs_root;
  90. sb->s_root = root;
  91. return 0;
  92. }
  93. static int configfs_get_sb(struct file_system_type *fs_type,
  94. int flags, const char *dev_name, void *data, struct vfsmount *mnt)
  95. {
  96. return get_sb_single(fs_type, flags, data, configfs_fill_super, mnt);
  97. }
  98. static struct file_system_type configfs_fs_type = {
  99. .owner = THIS_MODULE,
  100. .name = "configfs",
  101. .get_sb = configfs_get_sb,
  102. .kill_sb = kill_litter_super,
  103. };
  104. int configfs_pin_fs(void)
  105. {
  106. return simple_pin_fs(&configfs_fs_type, &configfs_mount,
  107. &configfs_mnt_count);
  108. }
  109. void configfs_release_fs(void)
  110. {
  111. simple_release_fs(&configfs_mount, &configfs_mnt_count);
  112. }
  113. static decl_subsys(config, NULL, NULL);
  114. static int __init configfs_init(void)
  115. {
  116. int err = -ENOMEM;
  117. configfs_dir_cachep = kmem_cache_create("configfs_dir_cache",
  118. sizeof(struct configfs_dirent),
  119. 0, 0, NULL, NULL);
  120. if (!configfs_dir_cachep)
  121. goto out;
  122. kset_set_kset_s(&config_subsys, kernel_subsys);
  123. err = subsystem_register(&config_subsys);
  124. if (err) {
  125. kmem_cache_destroy(configfs_dir_cachep);
  126. configfs_dir_cachep = NULL;
  127. goto out;
  128. }
  129. err = register_filesystem(&configfs_fs_type);
  130. if (err) {
  131. printk(KERN_ERR "configfs: Unable to register filesystem!\n");
  132. subsystem_unregister(&config_subsys);
  133. kmem_cache_destroy(configfs_dir_cachep);
  134. configfs_dir_cachep = NULL;
  135. }
  136. out:
  137. return err;
  138. }
  139. static void __exit configfs_exit(void)
  140. {
  141. unregister_filesystem(&configfs_fs_type);
  142. subsystem_unregister(&config_subsys);
  143. kmem_cache_destroy(configfs_dir_cachep);
  144. configfs_dir_cachep = NULL;
  145. }
  146. MODULE_AUTHOR("Oracle");
  147. MODULE_LICENSE("GPL");
  148. MODULE_VERSION("0.0.2");
  149. MODULE_DESCRIPTION("Simple RAM filesystem for user driven kernel subsystem configuration.");
  150. module_init(configfs_init);
  151. module_exit(configfs_exit);