xref: /linux-6.15/include/linux/ext2_fs.h (revision 4bedea94)
1 /*
2  *  linux/include/linux/ext2_fs.h
3  *
4  * Copyright (C) 1992, 1993, 1994, 1995
5  * Remy Card ([email protected])
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  *
9  *  from
10  *
11  *  linux/include/linux/minix_fs.h
12  *
13  *  Copyright (C) 1991, 1992  Linus Torvalds
14  */
15 
16 #ifndef _LINUX_EXT2_FS_H
17 #define _LINUX_EXT2_FS_H
18 
19 #include <linux/types.h>
20 #include <linux/ext2_fs_sb.h>
21 
22 /*
23  * The second extended filesystem constants/structures
24  */
25 
26 /*
27  * Define EXT2FS_DEBUG to produce debug messages
28  */
29 #undef EXT2FS_DEBUG
30 
31 /*
32  * Define EXT2_PREALLOCATE to preallocate data blocks for expanding files
33  */
34 #define EXT2_PREALLOCATE
35 #define EXT2_DEFAULT_PREALLOC_BLOCKS	8
36 
37 /*
38  * The second extended file system version
39  */
40 #define EXT2FS_DATE		"95/08/09"
41 #define EXT2FS_VERSION		"0.5b"
42 
43 /*
44  * Debug code
45  */
46 #ifdef EXT2FS_DEBUG
47 #	define ext2_debug(f, a...)	{ \
48 					printk ("EXT2-fs DEBUG (%s, %d): %s:", \
49 						__FILE__, __LINE__, __FUNCTION__); \
50 				  	printk (f, ## a); \
51 					}
52 #else
53 #	define ext2_debug(f, a...)	/**/
54 #endif
55 
56 /*
57  * Special inode numbers
58  */
59 #define	EXT2_BAD_INO		 1	/* Bad blocks inode */
60 #define EXT2_ROOT_INO		 2	/* Root inode */
61 #define EXT2_BOOT_LOADER_INO	 5	/* Boot loader inode */
62 #define EXT2_UNDEL_DIR_INO	 6	/* Undelete directory inode */
63 
64 /* First non-reserved inode for old ext2 filesystems */
65 #define EXT2_GOOD_OLD_FIRST_INO	11
66 
67 /*
68  * The second extended file system magic number
69  */
70 #define EXT2_SUPER_MAGIC	0xEF53
71 
72 #ifdef __KERNEL__
73 static inline struct ext2_sb_info *EXT2_SB(struct super_block *sb)
74 {
75 	return sb->s_fs_info;
76 }
77 #else
78 /* Assume that user mode programs are passing in an ext2fs superblock, not
79  * a kernel struct super_block.  This will allow us to call the feature-test
80  * macros from user land. */
81 #define EXT2_SB(sb)	(sb)
82 #endif
83 
84 /*
85  * Maximal count of links to a file
86  */
87 #define EXT2_LINK_MAX		32000
88 
89 /*
90  * Macro-instructions used to manage several block sizes
91  */
92 #define EXT2_MIN_BLOCK_SIZE		1024
93 #define	EXT2_MAX_BLOCK_SIZE		4096
94 #define EXT2_MIN_BLOCK_LOG_SIZE		  10
95 #ifdef __KERNEL__
96 # define EXT2_BLOCK_SIZE(s)		((s)->s_blocksize)
97 #else
98 # define EXT2_BLOCK_SIZE(s)		(EXT2_MIN_BLOCK_SIZE << (s)->s_log_block_size)
99 #endif
100 #define	EXT2_ADDR_PER_BLOCK(s)		(EXT2_BLOCK_SIZE(s) / sizeof (__u32))
101 #ifdef __KERNEL__
102 # define EXT2_BLOCK_SIZE_BITS(s)	((s)->s_blocksize_bits)
103 #else
104 # define EXT2_BLOCK_SIZE_BITS(s)	((s)->s_log_block_size + 10)
105 #endif
106 #ifdef __KERNEL__
107 #define	EXT2_ADDR_PER_BLOCK_BITS(s)	(EXT2_SB(s)->s_addr_per_block_bits)
108 #define EXT2_INODE_SIZE(s)		(EXT2_SB(s)->s_inode_size)
109 #define EXT2_FIRST_INO(s)		(EXT2_SB(s)->s_first_ino)
110 #else
111 #define EXT2_INODE_SIZE(s)	(((s)->s_rev_level == EXT2_GOOD_OLD_REV) ? \
112 				 EXT2_GOOD_OLD_INODE_SIZE : \
113 				 (s)->s_inode_size)
114 #define EXT2_FIRST_INO(s)	(((s)->s_rev_level == EXT2_GOOD_OLD_REV) ? \
115 				 EXT2_GOOD_OLD_FIRST_INO : \
116 				 (s)->s_first_ino)
117 #endif
118 
119 /*
120  * Macro-instructions used to manage fragments
121  */
122 #define EXT2_MIN_FRAG_SIZE		1024
123 #define	EXT2_MAX_FRAG_SIZE		4096
124 #define EXT2_MIN_FRAG_LOG_SIZE		  10
125 #ifdef __KERNEL__
126 # define EXT2_FRAG_SIZE(s)		(EXT2_SB(s)->s_frag_size)
127 # define EXT2_FRAGS_PER_BLOCK(s)	(EXT2_SB(s)->s_frags_per_block)
128 #else
129 # define EXT2_FRAG_SIZE(s)		(EXT2_MIN_FRAG_SIZE << (s)->s_log_frag_size)
130 # define EXT2_FRAGS_PER_BLOCK(s)	(EXT2_BLOCK_SIZE(s) / EXT2_FRAG_SIZE(s))
131 #endif
132 
133 /*
134  * Structure of a blocks group descriptor
135  */
136 struct ext2_group_desc
137 {
138 	__le32	bg_block_bitmap;		/* Blocks bitmap block */
139 	__le32	bg_inode_bitmap;		/* Inodes bitmap block */
140 	__le32	bg_inode_table;		/* Inodes table block */
141 	__le16	bg_free_blocks_count;	/* Free blocks count */
142 	__le16	bg_free_inodes_count;	/* Free inodes count */
143 	__le16	bg_used_dirs_count;	/* Directories count */
144 	__le16	bg_pad;
145 	__le32	bg_reserved[3];
146 };
147 
148 /*
149  * Macro-instructions used to manage group descriptors
150  */
151 #ifdef __KERNEL__
152 # define EXT2_BLOCKS_PER_GROUP(s)	(EXT2_SB(s)->s_blocks_per_group)
153 # define EXT2_DESC_PER_BLOCK(s)		(EXT2_SB(s)->s_desc_per_block)
154 # define EXT2_INODES_PER_GROUP(s)	(EXT2_SB(s)->s_inodes_per_group)
155 # define EXT2_DESC_PER_BLOCK_BITS(s)	(EXT2_SB(s)->s_desc_per_block_bits)
156 #else
157 # define EXT2_BLOCKS_PER_GROUP(s)	((s)->s_blocks_per_group)
158 # define EXT2_DESC_PER_BLOCK(s)		(EXT2_BLOCK_SIZE(s) / sizeof (struct ext2_group_desc))
159 # define EXT2_INODES_PER_GROUP(s)	((s)->s_inodes_per_group)
160 #endif
161 
162 /*
163  * Constants relative to the data blocks
164  */
165 #define	EXT2_NDIR_BLOCKS		12
166 #define	EXT2_IND_BLOCK			EXT2_NDIR_BLOCKS
167 #define	EXT2_DIND_BLOCK			(EXT2_IND_BLOCK + 1)
168 #define	EXT2_TIND_BLOCK			(EXT2_DIND_BLOCK + 1)
169 #define	EXT2_N_BLOCKS			(EXT2_TIND_BLOCK + 1)
170 
171 /*
172  * Inode flags
173  */
174 #define	EXT2_SECRM_FL			0x00000001 /* Secure deletion */
175 #define	EXT2_UNRM_FL			0x00000002 /* Undelete */
176 #define	EXT2_COMPR_FL			0x00000004 /* Compress file */
177 #define EXT2_SYNC_FL			0x00000008 /* Synchronous updates */
178 #define EXT2_IMMUTABLE_FL		0x00000010 /* Immutable file */
179 #define EXT2_APPEND_FL			0x00000020 /* writes to file may only append */
180 #define EXT2_NODUMP_FL			0x00000040 /* do not dump file */
181 #define EXT2_NOATIME_FL			0x00000080 /* do not update atime */
182 /* Reserved for compression usage... */
183 #define EXT2_DIRTY_FL			0x00000100
184 #define EXT2_COMPRBLK_FL		0x00000200 /* One or more compressed clusters */
185 #define EXT2_NOCOMP_FL			0x00000400 /* Don't compress */
186 #define EXT2_ECOMPR_FL			0x00000800 /* Compression error */
187 /* End compression flags --- maybe not all used */
188 #define EXT2_BTREE_FL			0x00001000 /* btree format dir */
189 #define EXT2_INDEX_FL			0x00001000 /* hash-indexed directory */
190 #define EXT2_IMAGIC_FL			0x00002000 /* AFS directory */
191 #define EXT2_JOURNAL_DATA_FL		0x00004000 /* Reserved for ext3 */
192 #define EXT2_NOTAIL_FL			0x00008000 /* file tail should not be merged */
193 #define EXT2_DIRSYNC_FL			0x00010000 /* dirsync behaviour (directories only) */
194 #define EXT2_TOPDIR_FL			0x00020000 /* Top of directory hierarchies*/
195 #define EXT2_RESERVED_FL		0x80000000 /* reserved for ext2 lib */
196 
197 #define EXT2_FL_USER_VISIBLE		0x0003DFFF /* User visible flags */
198 #define EXT2_FL_USER_MODIFIABLE		0x000380FF /* User modifiable flags */
199 
200 /*
201  * ioctl commands
202  */
203 #define	EXT2_IOC_GETFLAGS		_IOR('f', 1, long)
204 #define	EXT2_IOC_SETFLAGS		_IOW('f', 2, long)
205 #define	EXT2_IOC_GETVERSION		_IOR('v', 1, long)
206 #define	EXT2_IOC_SETVERSION		_IOW('v', 2, long)
207 
208 /*
209  * Structure of an inode on the disk
210  */
211 struct ext2_inode {
212 	__le16	i_mode;		/* File mode */
213 	__le16	i_uid;		/* Low 16 bits of Owner Uid */
214 	__le32	i_size;		/* Size in bytes */
215 	__le32	i_atime;	/* Access time */
216 	__le32	i_ctime;	/* Creation time */
217 	__le32	i_mtime;	/* Modification time */
218 	__le32	i_dtime;	/* Deletion Time */
219 	__le16	i_gid;		/* Low 16 bits of Group Id */
220 	__le16	i_links_count;	/* Links count */
221 	__le32	i_blocks;	/* Blocks count */
222 	__le32	i_flags;	/* File flags */
223 	union {
224 		struct {
225 			__le32  l_i_reserved1;
226 		} linux1;
227 		struct {
228 			__le32  h_i_translator;
229 		} hurd1;
230 		struct {
231 			__le32  m_i_reserved1;
232 		} masix1;
233 	} osd1;				/* OS dependent 1 */
234 	__le32	i_block[EXT2_N_BLOCKS];/* Pointers to blocks */
235 	__le32	i_generation;	/* File version (for NFS) */
236 	__le32	i_file_acl;	/* File ACL */
237 	__le32	i_dir_acl;	/* Directory ACL */
238 	__le32	i_faddr;	/* Fragment address */
239 	union {
240 		struct {
241 			__u8	l_i_frag;	/* Fragment number */
242 			__u8	l_i_fsize;	/* Fragment size */
243 			__u16	i_pad1;
244 			__le16	l_i_uid_high;	/* these 2 fields    */
245 			__le16	l_i_gid_high;	/* were reserved2[0] */
246 			__u32	l_i_reserved2;
247 		} linux2;
248 		struct {
249 			__u8	h_i_frag;	/* Fragment number */
250 			__u8	h_i_fsize;	/* Fragment size */
251 			__le16	h_i_mode_high;
252 			__le16	h_i_uid_high;
253 			__le16	h_i_gid_high;
254 			__le32	h_i_author;
255 		} hurd2;
256 		struct {
257 			__u8	m_i_frag;	/* Fragment number */
258 			__u8	m_i_fsize;	/* Fragment size */
259 			__u16	m_pad1;
260 			__u32	m_i_reserved2[2];
261 		} masix2;
262 	} osd2;				/* OS dependent 2 */
263 };
264 
265 #define i_size_high	i_dir_acl
266 
267 #if defined(__KERNEL__) || defined(__linux__)
268 #define i_reserved1	osd1.linux1.l_i_reserved1
269 #define i_frag		osd2.linux2.l_i_frag
270 #define i_fsize		osd2.linux2.l_i_fsize
271 #define i_uid_low	i_uid
272 #define i_gid_low	i_gid
273 #define i_uid_high	osd2.linux2.l_i_uid_high
274 #define i_gid_high	osd2.linux2.l_i_gid_high
275 #define i_reserved2	osd2.linux2.l_i_reserved2
276 #endif
277 
278 #ifdef	__hurd__
279 #define i_translator	osd1.hurd1.h_i_translator
280 #define i_frag		osd2.hurd2.h_i_frag;
281 #define i_fsize		osd2.hurd2.h_i_fsize;
282 #define i_uid_high	osd2.hurd2.h_i_uid_high
283 #define i_gid_high	osd2.hurd2.h_i_gid_high
284 #define i_author	osd2.hurd2.h_i_author
285 #endif
286 
287 #ifdef	__masix__
288 #define i_reserved1	osd1.masix1.m_i_reserved1
289 #define i_frag		osd2.masix2.m_i_frag
290 #define i_fsize		osd2.masix2.m_i_fsize
291 #define i_reserved2	osd2.masix2.m_i_reserved2
292 #endif
293 
294 /*
295  * File system states
296  */
297 #define	EXT2_VALID_FS			0x0001	/* Unmounted cleanly */
298 #define	EXT2_ERROR_FS			0x0002	/* Errors detected */
299 
300 /*
301  * Mount flags
302  */
303 #define EXT2_MOUNT_CHECK		0x0001	/* Do mount-time checks */
304 #define EXT2_MOUNT_OLDALLOC		0x0002  /* Don't use the new Orlov allocator */
305 #define EXT2_MOUNT_GRPID		0x0004	/* Create files with directory's group */
306 #define EXT2_MOUNT_DEBUG		0x0008	/* Some debugging messages */
307 #define EXT2_MOUNT_ERRORS_CONT		0x0010	/* Continue on errors */
308 #define EXT2_MOUNT_ERRORS_RO		0x0020	/* Remount fs ro on errors */
309 #define EXT2_MOUNT_ERRORS_PANIC		0x0040	/* Panic on errors */
310 #define EXT2_MOUNT_MINIX_DF		0x0080	/* Mimics the Minix statfs */
311 #define EXT2_MOUNT_NOBH			0x0100	/* No buffer_heads */
312 #define EXT2_MOUNT_NO_UID32		0x0200  /* Disable 32-bit UIDs */
313 #define EXT2_MOUNT_XATTR_USER		0x4000	/* Extended user attributes */
314 #define EXT2_MOUNT_POSIX_ACL		0x8000	/* POSIX Access Control Lists */
315 
316 #define clear_opt(o, opt)		o &= ~EXT2_MOUNT_##opt
317 #define set_opt(o, opt)			o |= EXT2_MOUNT_##opt
318 #define test_opt(sb, opt)		(EXT2_SB(sb)->s_mount_opt & \
319 					 EXT2_MOUNT_##opt)
320 /*
321  * Maximal mount counts between two filesystem checks
322  */
323 #define EXT2_DFL_MAX_MNT_COUNT		20	/* Allow 20 mounts */
324 #define EXT2_DFL_CHECKINTERVAL		0	/* Don't use interval check */
325 
326 /*
327  * Behaviour when detecting errors
328  */
329 #define EXT2_ERRORS_CONTINUE		1	/* Continue execution */
330 #define EXT2_ERRORS_RO			2	/* Remount fs read-only */
331 #define EXT2_ERRORS_PANIC		3	/* Panic */
332 #define EXT2_ERRORS_DEFAULT		EXT2_ERRORS_CONTINUE
333 
334 /*
335  * Structure of the super block
336  */
337 struct ext2_super_block {
338 	__le32	s_inodes_count;		/* Inodes count */
339 	__le32	s_blocks_count;		/* Blocks count */
340 	__le32	s_r_blocks_count;	/* Reserved blocks count */
341 	__le32	s_free_blocks_count;	/* Free blocks count */
342 	__le32	s_free_inodes_count;	/* Free inodes count */
343 	__le32	s_first_data_block;	/* First Data Block */
344 	__le32	s_log_block_size;	/* Block size */
345 	__le32	s_log_frag_size;	/* Fragment size */
346 	__le32	s_blocks_per_group;	/* # Blocks per group */
347 	__le32	s_frags_per_group;	/* # Fragments per group */
348 	__le32	s_inodes_per_group;	/* # Inodes per group */
349 	__le32	s_mtime;		/* Mount time */
350 	__le32	s_wtime;		/* Write time */
351 	__le16	s_mnt_count;		/* Mount count */
352 	__le16	s_max_mnt_count;	/* Maximal mount count */
353 	__le16	s_magic;		/* Magic signature */
354 	__le16	s_state;		/* File system state */
355 	__le16	s_errors;		/* Behaviour when detecting errors */
356 	__le16	s_minor_rev_level; 	/* minor revision level */
357 	__le32	s_lastcheck;		/* time of last check */
358 	__le32	s_checkinterval;	/* max. time between checks */
359 	__le32	s_creator_os;		/* OS */
360 	__le32	s_rev_level;		/* Revision level */
361 	__le16	s_def_resuid;		/* Default uid for reserved blocks */
362 	__le16	s_def_resgid;		/* Default gid for reserved blocks */
363 	/*
364 	 * These fields are for EXT2_DYNAMIC_REV superblocks only.
365 	 *
366 	 * Note: the difference between the compatible feature set and
367 	 * the incompatible feature set is that if there is a bit set
368 	 * in the incompatible feature set that the kernel doesn't
369 	 * know about, it should refuse to mount the filesystem.
370 	 *
371 	 * e2fsck's requirements are more strict; if it doesn't know
372 	 * about a feature in either the compatible or incompatible
373 	 * feature set, it must abort and not try to meddle with
374 	 * things it doesn't understand...
375 	 */
376 	__le32	s_first_ino; 		/* First non-reserved inode */
377 	__le16   s_inode_size; 		/* size of inode structure */
378 	__le16	s_block_group_nr; 	/* block group # of this superblock */
379 	__le32	s_feature_compat; 	/* compatible feature set */
380 	__le32	s_feature_incompat; 	/* incompatible feature set */
381 	__le32	s_feature_ro_compat; 	/* readonly-compatible feature set */
382 	__u8	s_uuid[16];		/* 128-bit uuid for volume */
383 	char	s_volume_name[16]; 	/* volume name */
384 	char	s_last_mounted[64]; 	/* directory where last mounted */
385 	__le32	s_algorithm_usage_bitmap; /* For compression */
386 	/*
387 	 * Performance hints.  Directory preallocation should only
388 	 * happen if the EXT2_COMPAT_PREALLOC flag is on.
389 	 */
390 	__u8	s_prealloc_blocks;	/* Nr of blocks to try to preallocate*/
391 	__u8	s_prealloc_dir_blocks;	/* Nr to preallocate for dirs */
392 	__u16	s_padding1;
393 	/*
394 	 * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
395 	 */
396 	__u8	s_journal_uuid[16];	/* uuid of journal superblock */
397 	__u32	s_journal_inum;		/* inode number of journal file */
398 	__u32	s_journal_dev;		/* device number of journal file */
399 	__u32	s_last_orphan;		/* start of list of inodes to delete */
400 	__u32	s_hash_seed[4];		/* HTREE hash seed */
401 	__u8	s_def_hash_version;	/* Default hash version to use */
402 	__u8	s_reserved_char_pad;
403 	__u16	s_reserved_word_pad;
404 	__le32	s_default_mount_opts;
405  	__le32	s_first_meta_bg; 	/* First metablock block group */
406 	__u32	s_reserved[190];	/* Padding to the end of the block */
407 };
408 
409 /*
410  * Codes for operating systems
411  */
412 #define EXT2_OS_LINUX		0
413 #define EXT2_OS_HURD		1
414 #define EXT2_OS_MASIX		2
415 #define EXT2_OS_FREEBSD		3
416 #define EXT2_OS_LITES		4
417 
418 /*
419  * Revision levels
420  */
421 #define EXT2_GOOD_OLD_REV	0	/* The good old (original) format */
422 #define EXT2_DYNAMIC_REV	1 	/* V2 format w/ dynamic inode sizes */
423 
424 #define EXT2_CURRENT_REV	EXT2_GOOD_OLD_REV
425 #define EXT2_MAX_SUPP_REV	EXT2_DYNAMIC_REV
426 
427 #define EXT2_GOOD_OLD_INODE_SIZE 128
428 
429 /*
430  * Feature set definitions
431  */
432 
433 #define EXT2_HAS_COMPAT_FEATURE(sb,mask)			\
434 	( EXT2_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask) )
435 #define EXT2_HAS_RO_COMPAT_FEATURE(sb,mask)			\
436 	( EXT2_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask) )
437 #define EXT2_HAS_INCOMPAT_FEATURE(sb,mask)			\
438 	( EXT2_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask) )
439 #define EXT2_SET_COMPAT_FEATURE(sb,mask)			\
440 	EXT2_SB(sb)->s_es->s_feature_compat |= cpu_to_le32(mask)
441 #define EXT2_SET_RO_COMPAT_FEATURE(sb,mask)			\
442 	EXT2_SB(sb)->s_es->s_feature_ro_compat |= cpu_to_le32(mask)
443 #define EXT2_SET_INCOMPAT_FEATURE(sb,mask)			\
444 	EXT2_SB(sb)->s_es->s_feature_incompat |= cpu_to_le32(mask)
445 #define EXT2_CLEAR_COMPAT_FEATURE(sb,mask)			\
446 	EXT2_SB(sb)->s_es->s_feature_compat &= ~cpu_to_le32(mask)
447 #define EXT2_CLEAR_RO_COMPAT_FEATURE(sb,mask)			\
448 	EXT2_SB(sb)->s_es->s_feature_ro_compat &= ~cpu_to_le32(mask)
449 #define EXT2_CLEAR_INCOMPAT_FEATURE(sb,mask)			\
450 	EXT2_SB(sb)->s_es->s_feature_incompat &= ~cpu_to_le32(mask)
451 
452 #define EXT2_FEATURE_COMPAT_DIR_PREALLOC	0x0001
453 #define EXT2_FEATURE_COMPAT_IMAGIC_INODES	0x0002
454 #define EXT3_FEATURE_COMPAT_HAS_JOURNAL		0x0004
455 #define EXT2_FEATURE_COMPAT_EXT_ATTR		0x0008
456 #define EXT2_FEATURE_COMPAT_RESIZE_INO		0x0010
457 #define EXT2_FEATURE_COMPAT_DIR_INDEX		0x0020
458 #define EXT2_FEATURE_COMPAT_ANY			0xffffffff
459 
460 #define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER	0x0001
461 #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE	0x0002
462 #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR	0x0004
463 #define EXT2_FEATURE_RO_COMPAT_ANY		0xffffffff
464 
465 #define EXT2_FEATURE_INCOMPAT_COMPRESSION	0x0001
466 #define EXT2_FEATURE_INCOMPAT_FILETYPE		0x0002
467 #define EXT3_FEATURE_INCOMPAT_RECOVER		0x0004
468 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV	0x0008
469 #define EXT2_FEATURE_INCOMPAT_META_BG		0x0010
470 #define EXT2_FEATURE_INCOMPAT_ANY		0xffffffff
471 
472 #define EXT2_FEATURE_COMPAT_SUPP	EXT2_FEATURE_COMPAT_EXT_ATTR
473 #define EXT2_FEATURE_INCOMPAT_SUPP	(EXT2_FEATURE_INCOMPAT_FILETYPE| \
474 					 EXT2_FEATURE_INCOMPAT_META_BG)
475 #define EXT2_FEATURE_RO_COMPAT_SUPP	(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
476 					 EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
477 					 EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
478 #define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED	~EXT2_FEATURE_RO_COMPAT_SUPP
479 #define EXT2_FEATURE_INCOMPAT_UNSUPPORTED	~EXT2_FEATURE_INCOMPAT_SUPP
480 
481 /*
482  * Default values for user and/or group using reserved blocks
483  */
484 #define	EXT2_DEF_RESUID		0
485 #define	EXT2_DEF_RESGID		0
486 
487 /*
488  * Default mount options
489  */
490 #define EXT2_DEFM_DEBUG		0x0001
491 #define EXT2_DEFM_BSDGROUPS	0x0002
492 #define EXT2_DEFM_XATTR_USER	0x0004
493 #define EXT2_DEFM_ACL		0x0008
494 #define EXT2_DEFM_UID16		0x0010
495     /* Not used by ext2, but reserved for use by ext3 */
496 #define EXT3_DEFM_JMODE		0x0060
497 #define EXT3_DEFM_JMODE_DATA	0x0020
498 #define EXT3_DEFM_JMODE_ORDERED	0x0040
499 #define EXT3_DEFM_JMODE_WBACK	0x0060
500 
501 /*
502  * Structure of a directory entry
503  */
504 #define EXT2_NAME_LEN 255
505 
506 struct ext2_dir_entry {
507 	__le32	inode;			/* Inode number */
508 	__le16	rec_len;		/* Directory entry length */
509 	__le16	name_len;		/* Name length */
510 	char	name[EXT2_NAME_LEN];	/* File name */
511 };
512 
513 /*
514  * The new version of the directory entry.  Since EXT2 structures are
515  * stored in intel byte order, and the name_len field could never be
516  * bigger than 255 chars, it's safe to reclaim the extra byte for the
517  * file_type field.
518  */
519 struct ext2_dir_entry_2 {
520 	__le32	inode;			/* Inode number */
521 	__le16	rec_len;		/* Directory entry length */
522 	__u8	name_len;		/* Name length */
523 	__u8	file_type;
524 	char	name[EXT2_NAME_LEN];	/* File name */
525 };
526 
527 /*
528  * Ext2 directory file types.  Only the low 3 bits are used.  The
529  * other bits are reserved for now.
530  */
531 enum {
532 	EXT2_FT_UNKNOWN,
533 	EXT2_FT_REG_FILE,
534 	EXT2_FT_DIR,
535 	EXT2_FT_CHRDEV,
536 	EXT2_FT_BLKDEV,
537 	EXT2_FT_FIFO,
538 	EXT2_FT_SOCK,
539 	EXT2_FT_SYMLINK,
540 	EXT2_FT_MAX
541 };
542 
543 /*
544  * EXT2_DIR_PAD defines the directory entries boundaries
545  *
546  * NOTE: It must be a multiple of 4
547  */
548 #define EXT2_DIR_PAD		 	4
549 #define EXT2_DIR_ROUND 			(EXT2_DIR_PAD - 1)
550 #define EXT2_DIR_REC_LEN(name_len)	(((name_len) + 8 + EXT2_DIR_ROUND) & \
551 					 ~EXT2_DIR_ROUND)
552 
553 #endif	/* _LINUX_EXT2_FS_H */
554