/include/linux/exportfs.h

https://bitbucket.org/thekraven/iscream_thunderc-2.6.35 · C++ Header · 178 lines · 60 code · 16 blank · 102 comment · 0 complexity · 560c08151ea83cbf3f13638d70d80040 MD5 · raw file

  1. #ifndef LINUX_EXPORTFS_H
  2. #define LINUX_EXPORTFS_H 1
  3. #include <linux/types.h>
  4. struct dentry;
  5. struct inode;
  6. struct super_block;
  7. struct vfsmount;
  8. /*
  9. * The fileid_type identifies how the file within the filesystem is encoded.
  10. * In theory this is freely set and parsed by the filesystem, but we try to
  11. * stick to conventions so we can share some generic code and don't confuse
  12. * sniffers like ethereal/wireshark.
  13. *
  14. * The filesystem must not use the value '0' or '0xff'.
  15. */
  16. enum fid_type {
  17. /*
  18. * The root, or export point, of the filesystem.
  19. * (Never actually passed down to the filesystem.
  20. */
  21. FILEID_ROOT = 0,
  22. /*
  23. * 32bit inode number, 32 bit generation number.
  24. */
  25. FILEID_INO32_GEN = 1,
  26. /*
  27. * 32bit inode number, 32 bit generation number,
  28. * 32 bit parent directory inode number.
  29. */
  30. FILEID_INO32_GEN_PARENT = 2,
  31. /*
  32. * 64 bit object ID, 64 bit root object ID,
  33. * 32 bit generation number.
  34. */
  35. FILEID_BTRFS_WITHOUT_PARENT = 0x4d,
  36. /*
  37. * 64 bit object ID, 64 bit root object ID,
  38. * 32 bit generation number,
  39. * 64 bit parent object ID, 32 bit parent generation.
  40. */
  41. FILEID_BTRFS_WITH_PARENT = 0x4e,
  42. /*
  43. * 64 bit object ID, 64 bit root object ID,
  44. * 32 bit generation number,
  45. * 64 bit parent object ID, 32 bit parent generation,
  46. * 64 bit parent root object ID.
  47. */
  48. FILEID_BTRFS_WITH_PARENT_ROOT = 0x4f,
  49. /*
  50. * 32 bit block number, 16 bit partition reference,
  51. * 16 bit unused, 32 bit generation number.
  52. */
  53. FILEID_UDF_WITHOUT_PARENT = 0x51,
  54. /*
  55. * 32 bit block number, 16 bit partition reference,
  56. * 16 bit unused, 32 bit generation number,
  57. * 32 bit parent block number, 32 bit parent generation number
  58. */
  59. FILEID_UDF_WITH_PARENT = 0x52,
  60. };
  61. struct fid {
  62. union {
  63. struct {
  64. u32 ino;
  65. u32 gen;
  66. u32 parent_ino;
  67. u32 parent_gen;
  68. } i32;
  69. struct {
  70. u32 block;
  71. u16 partref;
  72. u16 parent_partref;
  73. u32 generation;
  74. u32 parent_block;
  75. u32 parent_generation;
  76. } udf;
  77. __u32 raw[0];
  78. };
  79. };
  80. /**
  81. * struct export_operations - for nfsd to communicate with file systems
  82. * @encode_fh: encode a file handle fragment from a dentry
  83. * @fh_to_dentry: find the implied object and get a dentry for it
  84. * @fh_to_parent: find the implied object's parent and get a dentry for it
  85. * @get_name: find the name for a given inode in a given directory
  86. * @get_parent: find the parent of a given directory
  87. * @commit_metadata: commit metadata changes to stable storage
  88. *
  89. * See Documentation/filesystems/nfs/Exporting for details on how to use
  90. * this interface correctly.
  91. *
  92. * encode_fh:
  93. * @encode_fh should store in the file handle fragment @fh (using at most
  94. * @max_len bytes) information that can be used by @decode_fh to recover the
  95. * file refered to by the &struct dentry @de. If the @connectable flag is
  96. * set, the encode_fh() should store sufficient information so that a good
  97. * attempt can be made to find not only the file but also it's place in the
  98. * filesystem. This typically means storing a reference to de->d_parent in
  99. * the filehandle fragment. encode_fh() should return the number of bytes
  100. * stored or a negative error code such as %-ENOSPC
  101. *
  102. * fh_to_dentry:
  103. * @fh_to_dentry is given a &struct super_block (@sb) and a file handle
  104. * fragment (@fh, @fh_len). It should return a &struct dentry which refers
  105. * to the same file that the file handle fragment refers to. If it cannot,
  106. * it should return a %NULL pointer if the file was found but no acceptable
  107. * &dentries were available, or an %ERR_PTR error code indicating why it
  108. * couldn't be found (e.g. %ENOENT or %ENOMEM). Any suitable dentry can be
  109. * returned including, if necessary, a new dentry created with d_alloc_root.
  110. * The caller can then find any other extant dentries by following the
  111. * d_alias links.
  112. *
  113. * fh_to_parent:
  114. * Same as @fh_to_dentry, except that it returns a pointer to the parent
  115. * dentry if it was encoded into the filehandle fragment by @encode_fh.
  116. *
  117. * get_name:
  118. * @get_name should find a name for the given @child in the given @parent
  119. * directory. The name should be stored in the @name (with the
  120. * understanding that it is already pointing to a a %NAME_MAX+1 sized
  121. * buffer. get_name() should return %0 on success, a negative error code
  122. * or error. @get_name will be called without @parent->i_mutex held.
  123. *
  124. * get_parent:
  125. * @get_parent should find the parent directory for the given @child which
  126. * is also a directory. In the event that it cannot be found, or storage
  127. * space cannot be allocated, a %ERR_PTR should be returned.
  128. *
  129. * commit_metadata:
  130. * @commit_metadata should commit metadata changes to stable storage.
  131. *
  132. * Locking rules:
  133. * get_parent is called with child->d_inode->i_mutex down
  134. * get_name is not (which is possibly inconsistent)
  135. */
  136. struct export_operations {
  137. int (*encode_fh)(struct dentry *de, __u32 *fh, int *max_len,
  138. int connectable);
  139. struct dentry * (*fh_to_dentry)(struct super_block *sb, struct fid *fid,
  140. int fh_len, int fh_type);
  141. struct dentry * (*fh_to_parent)(struct super_block *sb, struct fid *fid,
  142. int fh_len, int fh_type);
  143. int (*get_name)(struct dentry *parent, char *name,
  144. struct dentry *child);
  145. struct dentry * (*get_parent)(struct dentry *child);
  146. int (*commit_metadata)(struct inode *inode);
  147. };
  148. extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,
  149. int *max_len, int connectable);
  150. extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
  151. int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *),
  152. void *context);
  153. /*
  154. * Generic helpers for filesystems.
  155. */
  156. extern struct dentry *generic_fh_to_dentry(struct super_block *sb,
  157. struct fid *fid, int fh_len, int fh_type,
  158. struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
  159. extern struct dentry *generic_fh_to_parent(struct super_block *sb,
  160. struct fid *fid, int fh_len, int fh_type,
  161. struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
  162. #endif /* LINUX_EXPORTFS_H */