2 * \file fsw_ext2_disk.h
3 * ext2 file system on-disk structures.
7 * Copyright (c) 2006 Christoph Pfisterer
8 * Portions Copyright (c) 1991-2006 by various Linux kernel contributors
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version 2
13 * of the License, or (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
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 02111-1307, USA.
25 #ifndef _FSW_EXT2_DISK_H_
26 #define _FSW_EXT2_DISK_H_
32 typedef fsw_s16 __s16
;
33 typedef fsw_u16 __u16
;
34 typedef fsw_s32 __s32
;
35 typedef fsw_u32 __u32
;
36 typedef fsw_s64 __s64
;
37 typedef fsw_u64 __u64
;
44 // from Linux kernel, include/linux/ext2_fs.h
48 * Special inode numbers
50 #define EXT2_BAD_INO 1 /* Bad blocks inode */
51 #define EXT2_ROOT_INO 2 /* Root inode */
52 #define EXT2_BOOT_LOADER_INO 5 /* Boot loader inode */
53 #define EXT2_UNDEL_DIR_INO 6 /* Undelete directory inode */
56 * The second extended file system magic number
58 #define EXT2_SUPER_MAGIC 0xEF53
61 * Macro-instructions used to manage several block sizes
63 #define EXT2_MIN_BLOCK_SIZE 1024
64 #define EXT2_MAX_BLOCK_SIZE 4096
65 #define EXT2_MIN_BLOCK_LOG_SIZE 10
66 #define EXT2_BLOCK_SIZE(s) (EXT2_MIN_BLOCK_SIZE << (s)->s_log_block_size)
67 #define EXT2_ADDR_PER_BLOCK(s) (EXT2_BLOCK_SIZE(s) / sizeof (__u32))
68 #define EXT2_BLOCK_SIZE_BITS(s) ((s)->s_log_block_size + 10)
69 #define EXT2_INODE_SIZE(s) (((s)->s_rev_level == EXT2_GOOD_OLD_REV) ? \
70 EXT2_GOOD_OLD_INODE_SIZE : \
72 #define EXT2_FIRST_INO(s) (((s)->s_rev_level == EXT2_GOOD_OLD_REV) ? \
73 EXT2_GOOD_OLD_FIRST_INO : \
77 * Structure of a blocks group descriptor
79 struct ext2_group_desc
81 __le32 bg_block_bitmap
; /* Blocks bitmap block */
82 __le32 bg_inode_bitmap
; /* Inodes bitmap block */
83 __le32 bg_inode_table
; /* Inodes table block */
84 __le16 bg_free_blocks_count
; /* Free blocks count */
85 __le16 bg_free_inodes_count
; /* Free inodes count */
86 __le16 bg_used_dirs_count
; /* Directories count */
88 __le32 bg_reserved
[3];
92 * Macro-instructions used to manage group descriptors
94 #define EXT2_BLOCKS_PER_GROUP(s) ((s)->s_blocks_per_group)
95 #define EXT2_DESC_PER_BLOCK(s) (EXT2_BLOCK_SIZE(s) / sizeof (struct ext2_group_desc))
96 #define EXT2_INODES_PER_GROUP(s) ((s)->s_inodes_per_group)
99 * Constants relative to the data blocks
101 #define EXT2_NDIR_BLOCKS 12
102 #define EXT2_IND_BLOCK EXT2_NDIR_BLOCKS
103 #define EXT2_DIND_BLOCK (EXT2_IND_BLOCK + 1)
104 #define EXT2_TIND_BLOCK (EXT2_DIND_BLOCK + 1)
105 #define EXT2_N_BLOCKS (EXT2_TIND_BLOCK + 1)
110 #define EXT2_SECRM_FL 0x00000001 /* Secure deletion */
111 #define EXT2_UNRM_FL 0x00000002 /* Undelete */
112 #define EXT2_COMPR_FL 0x00000004 /* Compress file */
113 #define EXT2_SYNC_FL 0x00000008 /* Synchronous updates */
114 #define EXT2_IMMUTABLE_FL 0x00000010 /* Immutable file */
115 #define EXT2_APPEND_FL 0x00000020 /* writes to file may only append */
116 #define EXT2_NODUMP_FL 0x00000040 /* do not dump file */
117 #define EXT2_NOATIME_FL 0x00000080 /* do not update atime */
118 /* Reserved for compression usage... */
119 #define EXT2_DIRTY_FL 0x00000100
120 #define EXT2_COMPRBLK_FL 0x00000200 /* One or more compressed clusters */
121 #define EXT2_NOCOMP_FL 0x00000400 /* Don't compress */
122 #define EXT2_ECOMPR_FL 0x00000800 /* Compression error */
123 /* End compression flags --- maybe not all used */
124 #define EXT2_BTREE_FL 0x00001000 /* btree format dir */
125 #define EXT2_INDEX_FL 0x00001000 /* hash-indexed directory */
126 #define EXT2_IMAGIC_FL 0x00002000 /* AFS directory */
127 #define EXT2_JOURNAL_DATA_FL 0x00004000 /* Reserved for ext3 */
128 #define EXT2_NOTAIL_FL 0x00008000 /* file tail should not be merged */
129 #define EXT2_DIRSYNC_FL 0x00010000 /* dirsync behaviour (directories only) */
130 #define EXT2_TOPDIR_FL 0x00020000 /* Top of directory hierarchies*/
131 #define EXT2_RESERVED_FL 0x80000000 /* reserved for ext2 lib */
133 #define EXT2_FL_USER_VISIBLE 0x0003DFFF /* User visible flags */
134 #define EXT2_FL_USER_MODIFIABLE 0x000380FF /* User modifiable flags */
137 * Structure of an inode on the disk
140 __le16 i_mode
; /* 0: File mode */
141 __le16 i_uid
; /* 2: Low 16 bits of Owner Uid */
142 __le32 i_size
; /* 4: Size in bytes */
143 __le32 i_atime
; /* 8: Access time */
144 __le32 i_ctime
; /* 12: Creation time */
145 __le32 i_mtime
; /* 16: Modification time */
146 __le32 i_dtime
; /* 20: Deletion Time */
147 __le16 i_gid
; /* 24: Low 16 bits of Group Id */
148 __le16 i_links_count
; /* 26: Links count */
149 __le32 i_blocks
; /* 28: Blocks count */
150 __le32 i_flags
; /* 32: File flags */
153 __le32 l_i_reserved1
;
156 __le32 h_i_translator
;
159 __le32 m_i_reserved1
;
161 } osd1
; /* 36: OS dependent 1 */
162 __le32 i_block
[EXT2_N_BLOCKS
];/* 40: Pointers to blocks */
163 __le32 i_generation
; /* 100: File version (for NFS) */
164 __le32 i_file_acl
; /* 104: File ACL */
165 __le32 i_dir_acl
; /* 108: Directory ACL */
166 __le32 i_faddr
; /* 112: Fragment address */
169 __u8 l_i_frag
; /* 116: Fragment number */
170 __u8 l_i_fsize
; /* 117: Fragment size */
172 __le16 l_i_uid_high
; /* 120: these 2 fields */
173 __le16 l_i_gid_high
; /* 122: were reserved2[0] */
177 __u8 h_i_frag
; /* Fragment number */
178 __u8 h_i_fsize
; /* Fragment size */
179 __le16 h_i_mode_high
;
185 __u8 m_i_frag
; /* Fragment number */
186 __u8 m_i_fsize
; /* Fragment size */
188 __u32 m_i_reserved2
[2];
190 } osd2
; /* OS dependent 2 */
193 #define i_size_high i_dir_acl
196 * Structure of the super block
198 struct ext2_super_block
{
199 __le32 s_inodes_count
; /* Inodes count */
200 __le32 s_blocks_count
; /* Blocks count */
201 __le32 s_r_blocks_count
; /* Reserved blocks count */
202 __le32 s_free_blocks_count
; /* Free blocks count */
203 __le32 s_free_inodes_count
; /* Free inodes count */
204 __le32 s_first_data_block
; /* First Data Block */
205 __le32 s_log_block_size
; /* Block size */
206 __le32 s_log_frag_size
; /* Fragment size */
207 __le32 s_blocks_per_group
; /* # Blocks per group */
208 __le32 s_frags_per_group
; /* # Fragments per group */
209 __le32 s_inodes_per_group
; /* # Inodes per group */
210 __le32 s_mtime
; /* Mount time */
211 __le32 s_wtime
; /* Write time */
212 __le16 s_mnt_count
; /* Mount count */
213 __le16 s_max_mnt_count
; /* Maximal mount count */
214 __le16 s_magic
; /* Magic signature */
215 __le16 s_state
; /* File system state */
216 __le16 s_errors
; /* Behaviour when detecting errors */
217 __le16 s_minor_rev_level
; /* minor revision level */
218 __le32 s_lastcheck
; /* time of last check */
219 __le32 s_checkinterval
; /* max. time between checks */
220 __le32 s_creator_os
; /* OS */
221 __le32 s_rev_level
; /* Revision level */
222 __le16 s_def_resuid
; /* Default uid for reserved blocks */
223 __le16 s_def_resgid
; /* Default gid for reserved blocks */
225 * These fields are for EXT2_DYNAMIC_REV superblocks only.
227 * Note: the difference between the compatible feature set and
228 * the incompatible feature set is that if there is a bit set
229 * in the incompatible feature set that the kernel doesn't
230 * know about, it should refuse to mount the filesystem.
232 * e2fsck's requirements are more strict; if it doesn't know
233 * about a feature in either the compatible or incompatible
234 * feature set, it must abort and not try to meddle with
235 * things it doesn't understand...
237 __le32 s_first_ino
; /* First non-reserved inode */
238 __le16 s_inode_size
; /* size of inode structure */
239 __le16 s_block_group_nr
; /* block group # of this superblock */
240 __le32 s_feature_compat
; /* compatible feature set */
241 __le32 s_feature_incompat
; /* incompatible feature set */
242 __le32 s_feature_ro_compat
; /* readonly-compatible feature set */
243 __u8 s_uuid
[16]; /* 128-bit uuid for volume */
244 char s_volume_name
[16]; /* volume name */
245 char s_last_mounted
[64]; /* directory where last mounted */
246 __le32 s_algorithm_usage_bitmap
; /* For compression */
248 * Performance hints. Directory preallocation should only
249 * happen if the EXT2_COMPAT_PREALLOC flag is on.
251 __u8 s_prealloc_blocks
; /* Nr of blocks to try to preallocate*/
252 __u8 s_prealloc_dir_blocks
; /* Nr to preallocate for dirs */
255 * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
257 __u8 s_journal_uuid
[16]; /* uuid of journal superblock */
258 __u32 s_journal_inum
; /* inode number of journal file */
259 __u32 s_journal_dev
; /* device number of journal file */
260 __u32 s_last_orphan
; /* start of list of inodes to delete */
261 __u32 s_hash_seed
[4]; /* HTREE hash seed */
262 __u8 s_def_hash_version
; /* Default hash version to use */
263 __u8 s_reserved_char_pad
;
264 __u16 s_reserved_word_pad
;
265 __le32 s_default_mount_opts
;
266 __le32 s_first_meta_bg
; /* First metablock block group */
267 __u32 s_reserved
[190]; /* Padding to the end of the block */
273 #define EXT2_GOOD_OLD_REV 0 /* The good old (original) format */
274 #define EXT2_DYNAMIC_REV 1 /* V2 format w/ dynamic inode sizes */
276 #define EXT2_CURRENT_REV EXT2_GOOD_OLD_REV
277 #define EXT2_MAX_SUPP_REV EXT2_DYNAMIC_REV
279 #define EXT2_GOOD_OLD_INODE_SIZE 128
282 * Feature set definitions
285 #define EXT2_HAS_COMPAT_FEATURE(sb,mask) \
286 ( EXT2_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask) )
287 #define EXT2_HAS_RO_COMPAT_FEATURE(sb,mask) \
288 ( EXT2_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask) )
289 #define EXT2_HAS_INCOMPAT_FEATURE(sb,mask) \
290 ( EXT2_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask) )
291 #define EXT2_SET_COMPAT_FEATURE(sb,mask) \
292 EXT2_SB(sb)->s_es->s_feature_compat |= cpu_to_le32(mask)
293 #define EXT2_SET_RO_COMPAT_FEATURE(sb,mask) \
294 EXT2_SB(sb)->s_es->s_feature_ro_compat |= cpu_to_le32(mask)
295 #define EXT2_SET_INCOMPAT_FEATURE(sb,mask) \
296 EXT2_SB(sb)->s_es->s_feature_incompat |= cpu_to_le32(mask)
297 #define EXT2_CLEAR_COMPAT_FEATURE(sb,mask) \
298 EXT2_SB(sb)->s_es->s_feature_compat &= ~cpu_to_le32(mask)
299 #define EXT2_CLEAR_RO_COMPAT_FEATURE(sb,mask) \
300 EXT2_SB(sb)->s_es->s_feature_ro_compat &= ~cpu_to_le32(mask)
301 #define EXT2_CLEAR_INCOMPAT_FEATURE(sb,mask) \
302 EXT2_SB(sb)->s_es->s_feature_incompat &= ~cpu_to_le32(mask)
304 #define EXT2_FEATURE_COMPAT_DIR_PREALLOC 0x0001
305 #define EXT2_FEATURE_COMPAT_IMAGIC_INODES 0x0002
306 #define EXT3_FEATURE_COMPAT_HAS_JOURNAL 0x0004
307 #define EXT2_FEATURE_COMPAT_EXT_ATTR 0x0008
308 #define EXT2_FEATURE_COMPAT_RESIZE_INO 0x0010
309 #define EXT2_FEATURE_COMPAT_DIR_INDEX 0x0020
310 #define EXT2_FEATURE_COMPAT_ANY 0xffffffff
312 #define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001
313 #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE 0x0002
314 #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR 0x0004
315 #define EXT2_FEATURE_RO_COMPAT_ANY 0xffffffff
317 #define EXT2_FEATURE_INCOMPAT_COMPRESSION 0x0001
318 #define EXT2_FEATURE_INCOMPAT_FILETYPE 0x0002
319 #define EXT3_FEATURE_INCOMPAT_RECOVER 0x0004
320 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV 0x0008
321 #define EXT2_FEATURE_INCOMPAT_META_BG 0x0010
322 #define EXT2_FEATURE_INCOMPAT_ANY 0xffffffff
325 #define EXT2_FEATURE_COMPAT_SUPP EXT2_FEATURE_COMPAT_EXT_ATTR
326 #define EXT2_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE| \
327 EXT2_FEATURE_INCOMPAT_META_BG)
328 #define EXT2_FEATURE_RO_COMPAT_SUPP (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
329 EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
330 EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
331 #define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED ~EXT2_FEATURE_RO_COMPAT_SUPP
332 #define EXT2_FEATURE_INCOMPAT_UNSUPPORTED ~EXT2_FEATURE_INCOMPAT_SUPP
336 * Structure of a directory entry
338 #define EXT2_NAME_LEN 255
340 struct ext2_dir_entry
{
341 __le32 inode
; /* Inode number */
342 __le16 rec_len
; /* Directory entry length */
343 __u8 name_len
; /* Name length */
345 char name
[EXT2_NAME_LEN
]; /* File name */
347 // NOTE: The original Linux kernel header defines ext2_dir_entry with the original
348 // layout and ext2_dir_entry_2 with the revised layout. We simply use the revised one.
351 * Ext2 directory file types. Only the low 3 bits are used. The
352 * other bits are reserved for now.