new helper: ext2_image_size()
[~shefty/rdma-dev.git] / include / linux / ext2_fs.h
1 /*
2  *  linux/include/linux/ext2_fs.h
3  *
4  * Copyright (C) 1992, 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
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/magic.h>
21 #include <linux/fs.h>
22
23 #include <linux/ext2_fs_sb.h>
24
25 /*
26  * The second extended filesystem constants/structures
27  */
28
29 /*
30  * Define EXT2FS_DEBUG to produce debug messages
31  */
32 #undef EXT2FS_DEBUG
33
34 /*
35  * Define EXT2_RESERVATION to reserve data blocks for expanding files
36  */
37 #define EXT2_DEFAULT_RESERVE_BLOCKS     8
38 /*max window size: 1024(direct blocks) + 3([t,d]indirect blocks) */
39 #define EXT2_MAX_RESERVE_BLOCKS         1027
40 #define EXT2_RESERVE_WINDOW_NOT_ALLOCATED 0
41 /*
42  * The second extended file system version
43  */
44 #define EXT2FS_DATE             "95/08/09"
45 #define EXT2FS_VERSION          "0.5b"
46
47 /*
48  * Debug code
49  */
50 #ifdef EXT2FS_DEBUG
51 #       define ext2_debug(f, a...)      { \
52                                         printk ("EXT2-fs DEBUG (%s, %d): %s:", \
53                                                 __FILE__, __LINE__, __func__); \
54                                         printk (f, ## a); \
55                                         }
56 #else
57 #       define ext2_debug(f, a...)      /**/
58 #endif
59
60 /*
61  * Special inode numbers
62  */
63 #define EXT2_BAD_INO             1      /* Bad blocks inode */
64 #define EXT2_ROOT_INO            2      /* Root inode */
65 #define EXT2_BOOT_LOADER_INO     5      /* Boot loader inode */
66 #define EXT2_UNDEL_DIR_INO       6      /* Undelete directory inode */
67
68 /* First non-reserved inode for old ext2 filesystems */
69 #define EXT2_GOOD_OLD_FIRST_INO 11
70
71 static inline struct ext2_sb_info *EXT2_SB(struct super_block *sb)
72 {
73         return sb->s_fs_info;
74 }
75
76 /*
77  * Maximal count of links to a file
78  */
79 #define EXT2_LINK_MAX           32000
80
81 /*
82  * Macro-instructions used to manage several block sizes
83  */
84 #define EXT2_MIN_BLOCK_SIZE             1024
85 #define EXT2_MAX_BLOCK_SIZE             4096
86 #define EXT2_MIN_BLOCK_LOG_SIZE           10
87 #define EXT2_BLOCK_SIZE(s)              ((s)->s_blocksize)
88 #define EXT2_ADDR_PER_BLOCK(s)          (EXT2_BLOCK_SIZE(s) / sizeof (__u32))
89 #define EXT2_BLOCK_SIZE_BITS(s)         ((s)->s_blocksize_bits)
90 #define EXT2_ADDR_PER_BLOCK_BITS(s)     (EXT2_SB(s)->s_addr_per_block_bits)
91 #define EXT2_INODE_SIZE(s)              (EXT2_SB(s)->s_inode_size)
92 #define EXT2_FIRST_INO(s)               (EXT2_SB(s)->s_first_ino)
93
94 /*
95  * Macro-instructions used to manage fragments
96  */
97 #define EXT2_MIN_FRAG_SIZE              1024
98 #define EXT2_MAX_FRAG_SIZE              4096
99 #define EXT2_MIN_FRAG_LOG_SIZE            10
100 #define EXT2_FRAG_SIZE(s)               (EXT2_SB(s)->s_frag_size)
101 #define EXT2_FRAGS_PER_BLOCK(s)         (EXT2_SB(s)->s_frags_per_block)
102
103 /*
104  * Structure of a blocks group descriptor
105  */
106 struct ext2_group_desc
107 {
108         __le32  bg_block_bitmap;                /* Blocks bitmap block */
109         __le32  bg_inode_bitmap;                /* Inodes bitmap block */
110         __le32  bg_inode_table;         /* Inodes table block */
111         __le16  bg_free_blocks_count;   /* Free blocks count */
112         __le16  bg_free_inodes_count;   /* Free inodes count */
113         __le16  bg_used_dirs_count;     /* Directories count */
114         __le16  bg_pad;
115         __le32  bg_reserved[3];
116 };
117
118 /*
119  * Macro-instructions used to manage group descriptors
120  */
121 #define EXT2_BLOCKS_PER_GROUP(s)        (EXT2_SB(s)->s_blocks_per_group)
122 #define EXT2_DESC_PER_BLOCK(s)          (EXT2_SB(s)->s_desc_per_block)
123 #define EXT2_INODES_PER_GROUP(s)        (EXT2_SB(s)->s_inodes_per_group)
124 #define EXT2_DESC_PER_BLOCK_BITS(s)     (EXT2_SB(s)->s_desc_per_block_bits)
125
126 /*
127  * Constants relative to the data blocks
128  */
129 #define EXT2_NDIR_BLOCKS                12
130 #define EXT2_IND_BLOCK                  EXT2_NDIR_BLOCKS
131 #define EXT2_DIND_BLOCK                 (EXT2_IND_BLOCK + 1)
132 #define EXT2_TIND_BLOCK                 (EXT2_DIND_BLOCK + 1)
133 #define EXT2_N_BLOCKS                   (EXT2_TIND_BLOCK + 1)
134
135 /*
136  * Inode flags (GETFLAGS/SETFLAGS)
137  */
138 #define EXT2_SECRM_FL                   FS_SECRM_FL     /* Secure deletion */
139 #define EXT2_UNRM_FL                    FS_UNRM_FL      /* Undelete */
140 #define EXT2_COMPR_FL                   FS_COMPR_FL     /* Compress file */
141 #define EXT2_SYNC_FL                    FS_SYNC_FL      /* Synchronous updates */
142 #define EXT2_IMMUTABLE_FL               FS_IMMUTABLE_FL /* Immutable file */
143 #define EXT2_APPEND_FL                  FS_APPEND_FL    /* writes to file may only append */
144 #define EXT2_NODUMP_FL                  FS_NODUMP_FL    /* do not dump file */
145 #define EXT2_NOATIME_FL                 FS_NOATIME_FL   /* do not update atime */
146 /* Reserved for compression usage... */
147 #define EXT2_DIRTY_FL                   FS_DIRTY_FL
148 #define EXT2_COMPRBLK_FL                FS_COMPRBLK_FL  /* One or more compressed clusters */
149 #define EXT2_NOCOMP_FL                  FS_NOCOMP_FL    /* Don't compress */
150 #define EXT2_ECOMPR_FL                  FS_ECOMPR_FL    /* Compression error */
151 /* End compression flags --- maybe not all used */      
152 #define EXT2_BTREE_FL                   FS_BTREE_FL     /* btree format dir */
153 #define EXT2_INDEX_FL                   FS_INDEX_FL     /* hash-indexed directory */
154 #define EXT2_IMAGIC_FL                  FS_IMAGIC_FL    /* AFS directory */
155 #define EXT2_JOURNAL_DATA_FL            FS_JOURNAL_DATA_FL /* Reserved for ext3 */
156 #define EXT2_NOTAIL_FL                  FS_NOTAIL_FL    /* file tail should not be merged */
157 #define EXT2_DIRSYNC_FL                 FS_DIRSYNC_FL   /* dirsync behaviour (directories only) */
158 #define EXT2_TOPDIR_FL                  FS_TOPDIR_FL    /* Top of directory hierarchies*/
159 #define EXT2_RESERVED_FL                FS_RESERVED_FL  /* reserved for ext2 lib */
160
161 #define EXT2_FL_USER_VISIBLE            FS_FL_USER_VISIBLE      /* User visible flags */
162 #define EXT2_FL_USER_MODIFIABLE         FS_FL_USER_MODIFIABLE   /* User modifiable flags */
163
164 /* Flags that should be inherited by new inodes from their parent. */
165 #define EXT2_FL_INHERITED (EXT2_SECRM_FL | EXT2_UNRM_FL | EXT2_COMPR_FL |\
166                            EXT2_SYNC_FL | EXT2_NODUMP_FL |\
167                            EXT2_NOATIME_FL | EXT2_COMPRBLK_FL |\
168                            EXT2_NOCOMP_FL | EXT2_JOURNAL_DATA_FL |\
169                            EXT2_NOTAIL_FL | EXT2_DIRSYNC_FL)
170
171 /* Flags that are appropriate for regular files (all but dir-specific ones). */
172 #define EXT2_REG_FLMASK (~(EXT2_DIRSYNC_FL | EXT2_TOPDIR_FL))
173
174 /* Flags that are appropriate for non-directories/regular files. */
175 #define EXT2_OTHER_FLMASK (EXT2_NODUMP_FL | EXT2_NOATIME_FL)
176
177 /* Mask out flags that are inappropriate for the given type of inode. */
178 static inline __u32 ext2_mask_flags(umode_t mode, __u32 flags)
179 {
180         if (S_ISDIR(mode))
181                 return flags;
182         else if (S_ISREG(mode))
183                 return flags & EXT2_REG_FLMASK;
184         else
185                 return flags & EXT2_OTHER_FLMASK;
186 }
187
188 /*
189  * ioctl commands
190  */
191 #define EXT2_IOC_GETFLAGS               FS_IOC_GETFLAGS
192 #define EXT2_IOC_SETFLAGS               FS_IOC_SETFLAGS
193 #define EXT2_IOC_GETVERSION             FS_IOC_GETVERSION
194 #define EXT2_IOC_SETVERSION             FS_IOC_SETVERSION
195 #define EXT2_IOC_GETRSVSZ               _IOR('f', 5, long)
196 #define EXT2_IOC_SETRSVSZ               _IOW('f', 6, long)
197
198 /*
199  * ioctl commands in 32 bit emulation
200  */
201 #define EXT2_IOC32_GETFLAGS             FS_IOC32_GETFLAGS
202 #define EXT2_IOC32_SETFLAGS             FS_IOC32_SETFLAGS
203 #define EXT2_IOC32_GETVERSION           FS_IOC32_GETVERSION
204 #define EXT2_IOC32_SETVERSION           FS_IOC32_SETVERSION
205
206 /*
207  * Structure of an inode on the disk
208  */
209 struct ext2_inode {
210         __le16  i_mode;         /* File mode */
211         __le16  i_uid;          /* Low 16 bits of Owner Uid */
212         __le32  i_size;         /* Size in bytes */
213         __le32  i_atime;        /* Access time */
214         __le32  i_ctime;        /* Creation time */
215         __le32  i_mtime;        /* Modification time */
216         __le32  i_dtime;        /* Deletion Time */
217         __le16  i_gid;          /* Low 16 bits of Group Id */
218         __le16  i_links_count;  /* Links count */
219         __le32  i_blocks;       /* Blocks count */
220         __le32  i_flags;        /* File flags */
221         union {
222                 struct {
223                         __le32  l_i_reserved1;
224                 } linux1;
225                 struct {
226                         __le32  h_i_translator;
227                 } hurd1;
228                 struct {
229                         __le32  m_i_reserved1;
230                 } masix1;
231         } osd1;                         /* OS dependent 1 */
232         __le32  i_block[EXT2_N_BLOCKS];/* Pointers to blocks */
233         __le32  i_generation;   /* File version (for NFS) */
234         __le32  i_file_acl;     /* File ACL */
235         __le32  i_dir_acl;      /* Directory ACL */
236         __le32  i_faddr;        /* Fragment address */
237         union {
238                 struct {
239                         __u8    l_i_frag;       /* Fragment number */
240                         __u8    l_i_fsize;      /* Fragment size */
241                         __u16   i_pad1;
242                         __le16  l_i_uid_high;   /* these 2 fields    */
243                         __le16  l_i_gid_high;   /* were reserved2[0] */
244                         __u32   l_i_reserved2;
245                 } linux2;
246                 struct {
247                         __u8    h_i_frag;       /* Fragment number */
248                         __u8    h_i_fsize;      /* Fragment size */
249                         __le16  h_i_mode_high;
250                         __le16  h_i_uid_high;
251                         __le16  h_i_gid_high;
252                         __le32  h_i_author;
253                 } hurd2;
254                 struct {
255                         __u8    m_i_frag;       /* Fragment number */
256                         __u8    m_i_fsize;      /* Fragment size */
257                         __u16   m_pad1;
258                         __u32   m_i_reserved2[2];
259                 } masix2;
260         } osd2;                         /* OS dependent 2 */
261 };
262
263 #define i_size_high     i_dir_acl
264
265 #define i_reserved1     osd1.linux1.l_i_reserved1
266 #define i_frag          osd2.linux2.l_i_frag
267 #define i_fsize         osd2.linux2.l_i_fsize
268 #define i_uid_low       i_uid
269 #define i_gid_low       i_gid
270 #define i_uid_high      osd2.linux2.l_i_uid_high
271 #define i_gid_high      osd2.linux2.l_i_gid_high
272 #define i_reserved2     osd2.linux2.l_i_reserved2
273
274 /*
275  * File system states
276  */
277 #define EXT2_VALID_FS                   0x0001  /* Unmounted cleanly */
278 #define EXT2_ERROR_FS                   0x0002  /* Errors detected */
279
280 /*
281  * Mount flags
282  */
283 #define EXT2_MOUNT_CHECK                0x000001  /* Do mount-time checks */
284 #define EXT2_MOUNT_OLDALLOC             0x000002  /* Don't use the new Orlov allocator */
285 #define EXT2_MOUNT_GRPID                0x000004  /* Create files with directory's group */
286 #define EXT2_MOUNT_DEBUG                0x000008  /* Some debugging messages */
287 #define EXT2_MOUNT_ERRORS_CONT          0x000010  /* Continue on errors */
288 #define EXT2_MOUNT_ERRORS_RO            0x000020  /* Remount fs ro on errors */
289 #define EXT2_MOUNT_ERRORS_PANIC         0x000040  /* Panic on errors */
290 #define EXT2_MOUNT_MINIX_DF             0x000080  /* Mimics the Minix statfs */
291 #define EXT2_MOUNT_NOBH                 0x000100  /* No buffer_heads */
292 #define EXT2_MOUNT_NO_UID32             0x000200  /* Disable 32-bit UIDs */
293 #define EXT2_MOUNT_XATTR_USER           0x004000  /* Extended user attributes */
294 #define EXT2_MOUNT_POSIX_ACL            0x008000  /* POSIX Access Control Lists */
295 #define EXT2_MOUNT_XIP                  0x010000  /* Execute in place */
296 #define EXT2_MOUNT_USRQUOTA             0x020000  /* user quota */
297 #define EXT2_MOUNT_GRPQUOTA             0x040000  /* group quota */
298 #define EXT2_MOUNT_RESERVATION          0x080000  /* Preallocation */
299
300
301 #define clear_opt(o, opt)               o &= ~EXT2_MOUNT_##opt
302 #define set_opt(o, opt)                 o |= EXT2_MOUNT_##opt
303 #define test_opt(sb, opt)               (EXT2_SB(sb)->s_mount_opt & \
304                                          EXT2_MOUNT_##opt)
305 /*
306  * Maximal mount counts between two filesystem checks
307  */
308 #define EXT2_DFL_MAX_MNT_COUNT          20      /* Allow 20 mounts */
309 #define EXT2_DFL_CHECKINTERVAL          0       /* Don't use interval check */
310
311 /*
312  * Behaviour when detecting errors
313  */
314 #define EXT2_ERRORS_CONTINUE            1       /* Continue execution */
315 #define EXT2_ERRORS_RO                  2       /* Remount fs read-only */
316 #define EXT2_ERRORS_PANIC               3       /* Panic */
317 #define EXT2_ERRORS_DEFAULT             EXT2_ERRORS_CONTINUE
318
319 /*
320  * Structure of the super block
321  */
322 struct ext2_super_block {
323         __le32  s_inodes_count;         /* Inodes count */
324         __le32  s_blocks_count;         /* Blocks count */
325         __le32  s_r_blocks_count;       /* Reserved blocks count */
326         __le32  s_free_blocks_count;    /* Free blocks count */
327         __le32  s_free_inodes_count;    /* Free inodes count */
328         __le32  s_first_data_block;     /* First Data Block */
329         __le32  s_log_block_size;       /* Block size */
330         __le32  s_log_frag_size;        /* Fragment size */
331         __le32  s_blocks_per_group;     /* # Blocks per group */
332         __le32  s_frags_per_group;      /* # Fragments per group */
333         __le32  s_inodes_per_group;     /* # Inodes per group */
334         __le32  s_mtime;                /* Mount time */
335         __le32  s_wtime;                /* Write time */
336         __le16  s_mnt_count;            /* Mount count */
337         __le16  s_max_mnt_count;        /* Maximal mount count */
338         __le16  s_magic;                /* Magic signature */
339         __le16  s_state;                /* File system state */
340         __le16  s_errors;               /* Behaviour when detecting errors */
341         __le16  s_minor_rev_level;      /* minor revision level */
342         __le32  s_lastcheck;            /* time of last check */
343         __le32  s_checkinterval;        /* max. time between checks */
344         __le32  s_creator_os;           /* OS */
345         __le32  s_rev_level;            /* Revision level */
346         __le16  s_def_resuid;           /* Default uid for reserved blocks */
347         __le16  s_def_resgid;           /* Default gid for reserved blocks */
348         /*
349          * These fields are for EXT2_DYNAMIC_REV superblocks only.
350          *
351          * Note: the difference between the compatible feature set and
352          * the incompatible feature set is that if there is a bit set
353          * in the incompatible feature set that the kernel doesn't
354          * know about, it should refuse to mount the filesystem.
355          * 
356          * e2fsck's requirements are more strict; if it doesn't know
357          * about a feature in either the compatible or incompatible
358          * feature set, it must abort and not try to meddle with
359          * things it doesn't understand...
360          */
361         __le32  s_first_ino;            /* First non-reserved inode */
362         __le16   s_inode_size;          /* size of inode structure */
363         __le16  s_block_group_nr;       /* block group # of this superblock */
364         __le32  s_feature_compat;       /* compatible feature set */
365         __le32  s_feature_incompat;     /* incompatible feature set */
366         __le32  s_feature_ro_compat;    /* readonly-compatible feature set */
367         __u8    s_uuid[16];             /* 128-bit uuid for volume */
368         char    s_volume_name[16];      /* volume name */
369         char    s_last_mounted[64];     /* directory where last mounted */
370         __le32  s_algorithm_usage_bitmap; /* For compression */
371         /*
372          * Performance hints.  Directory preallocation should only
373          * happen if the EXT2_COMPAT_PREALLOC flag is on.
374          */
375         __u8    s_prealloc_blocks;      /* Nr of blocks to try to preallocate*/
376         __u8    s_prealloc_dir_blocks;  /* Nr to preallocate for dirs */
377         __u16   s_padding1;
378         /*
379          * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
380          */
381         __u8    s_journal_uuid[16];     /* uuid of journal superblock */
382         __u32   s_journal_inum;         /* inode number of journal file */
383         __u32   s_journal_dev;          /* device number of journal file */
384         __u32   s_last_orphan;          /* start of list of inodes to delete */
385         __u32   s_hash_seed[4];         /* HTREE hash seed */
386         __u8    s_def_hash_version;     /* Default hash version to use */
387         __u8    s_reserved_char_pad;
388         __u16   s_reserved_word_pad;
389         __le32  s_default_mount_opts;
390         __le32  s_first_meta_bg;        /* First metablock block group */
391         __u32   s_reserved[190];        /* Padding to the end of the block */
392 };
393
394 /*
395  * Codes for operating systems
396  */
397 #define EXT2_OS_LINUX           0
398 #define EXT2_OS_HURD            1
399 #define EXT2_OS_MASIX           2
400 #define EXT2_OS_FREEBSD         3
401 #define EXT2_OS_LITES           4
402
403 /*
404  * Revision levels
405  */
406 #define EXT2_GOOD_OLD_REV       0       /* The good old (original) format */
407 #define EXT2_DYNAMIC_REV        1       /* V2 format w/ dynamic inode sizes */
408
409 #define EXT2_CURRENT_REV        EXT2_GOOD_OLD_REV
410 #define EXT2_MAX_SUPP_REV       EXT2_DYNAMIC_REV
411
412 #define EXT2_GOOD_OLD_INODE_SIZE 128
413
414 /*
415  * Feature set definitions
416  */
417
418 #define EXT2_HAS_COMPAT_FEATURE(sb,mask)                        \
419         ( EXT2_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask) )
420 #define EXT2_HAS_RO_COMPAT_FEATURE(sb,mask)                     \
421         ( EXT2_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask) )
422 #define EXT2_HAS_INCOMPAT_FEATURE(sb,mask)                      \
423         ( EXT2_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask) )
424 #define EXT2_SET_COMPAT_FEATURE(sb,mask)                        \
425         EXT2_SB(sb)->s_es->s_feature_compat |= cpu_to_le32(mask)
426 #define EXT2_SET_RO_COMPAT_FEATURE(sb,mask)                     \
427         EXT2_SB(sb)->s_es->s_feature_ro_compat |= cpu_to_le32(mask)
428 #define EXT2_SET_INCOMPAT_FEATURE(sb,mask)                      \
429         EXT2_SB(sb)->s_es->s_feature_incompat |= cpu_to_le32(mask)
430 #define EXT2_CLEAR_COMPAT_FEATURE(sb,mask)                      \
431         EXT2_SB(sb)->s_es->s_feature_compat &= ~cpu_to_le32(mask)
432 #define EXT2_CLEAR_RO_COMPAT_FEATURE(sb,mask)                   \
433         EXT2_SB(sb)->s_es->s_feature_ro_compat &= ~cpu_to_le32(mask)
434 #define EXT2_CLEAR_INCOMPAT_FEATURE(sb,mask)                    \
435         EXT2_SB(sb)->s_es->s_feature_incompat &= ~cpu_to_le32(mask)
436
437 #define EXT2_FEATURE_COMPAT_DIR_PREALLOC        0x0001
438 #define EXT2_FEATURE_COMPAT_IMAGIC_INODES       0x0002
439 #define EXT3_FEATURE_COMPAT_HAS_JOURNAL         0x0004
440 #define EXT2_FEATURE_COMPAT_EXT_ATTR            0x0008
441 #define EXT2_FEATURE_COMPAT_RESIZE_INO          0x0010
442 #define EXT2_FEATURE_COMPAT_DIR_INDEX           0x0020
443 #define EXT2_FEATURE_COMPAT_ANY                 0xffffffff
444
445 #define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER     0x0001
446 #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE       0x0002
447 #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR        0x0004
448 #define EXT2_FEATURE_RO_COMPAT_ANY              0xffffffff
449
450 #define EXT2_FEATURE_INCOMPAT_COMPRESSION       0x0001
451 #define EXT2_FEATURE_INCOMPAT_FILETYPE          0x0002
452 #define EXT3_FEATURE_INCOMPAT_RECOVER           0x0004
453 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV       0x0008
454 #define EXT2_FEATURE_INCOMPAT_META_BG           0x0010
455 #define EXT2_FEATURE_INCOMPAT_ANY               0xffffffff
456
457 #define EXT2_FEATURE_COMPAT_SUPP        EXT2_FEATURE_COMPAT_EXT_ATTR
458 #define EXT2_FEATURE_INCOMPAT_SUPP      (EXT2_FEATURE_INCOMPAT_FILETYPE| \
459                                          EXT2_FEATURE_INCOMPAT_META_BG)
460 #define EXT2_FEATURE_RO_COMPAT_SUPP     (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
461                                          EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
462                                          EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
463 #define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED      ~EXT2_FEATURE_RO_COMPAT_SUPP
464 #define EXT2_FEATURE_INCOMPAT_UNSUPPORTED       ~EXT2_FEATURE_INCOMPAT_SUPP
465
466 /*
467  * Default values for user and/or group using reserved blocks
468  */
469 #define EXT2_DEF_RESUID         0
470 #define EXT2_DEF_RESGID         0
471
472 /*
473  * Default mount options
474  */
475 #define EXT2_DEFM_DEBUG         0x0001
476 #define EXT2_DEFM_BSDGROUPS     0x0002
477 #define EXT2_DEFM_XATTR_USER    0x0004
478 #define EXT2_DEFM_ACL           0x0008
479 #define EXT2_DEFM_UID16         0x0010
480     /* Not used by ext2, but reserved for use by ext3 */
481 #define EXT3_DEFM_JMODE         0x0060 
482 #define EXT3_DEFM_JMODE_DATA    0x0020
483 #define EXT3_DEFM_JMODE_ORDERED 0x0040
484 #define EXT3_DEFM_JMODE_WBACK   0x0060
485
486 /*
487  * Structure of a directory entry
488  */
489 #define EXT2_NAME_LEN 255
490
491 struct ext2_dir_entry {
492         __le32  inode;                  /* Inode number */
493         __le16  rec_len;                /* Directory entry length */
494         __le16  name_len;               /* Name length */
495         char    name[EXT2_NAME_LEN];    /* File name */
496 };
497
498 /*
499  * The new version of the directory entry.  Since EXT2 structures are
500  * stored in intel byte order, and the name_len field could never be
501  * bigger than 255 chars, it's safe to reclaim the extra byte for the
502  * file_type field.
503  */
504 struct ext2_dir_entry_2 {
505         __le32  inode;                  /* Inode number */
506         __le16  rec_len;                /* Directory entry length */
507         __u8    name_len;               /* Name length */
508         __u8    file_type;
509         char    name[EXT2_NAME_LEN];    /* File name */
510 };
511
512 /*
513  * Ext2 directory file types.  Only the low 3 bits are used.  The
514  * other bits are reserved for now.
515  */
516 enum {
517         EXT2_FT_UNKNOWN         = 0,
518         EXT2_FT_REG_FILE        = 1,
519         EXT2_FT_DIR             = 2,
520         EXT2_FT_CHRDEV          = 3,
521         EXT2_FT_BLKDEV          = 4,
522         EXT2_FT_FIFO            = 5,
523         EXT2_FT_SOCK            = 6,
524         EXT2_FT_SYMLINK         = 7,
525         EXT2_FT_MAX
526 };
527
528 /*
529  * EXT2_DIR_PAD defines the directory entries boundaries
530  *
531  * NOTE: It must be a multiple of 4
532  */
533 #define EXT2_DIR_PAD                    4
534 #define EXT2_DIR_ROUND                  (EXT2_DIR_PAD - 1)
535 #define EXT2_DIR_REC_LEN(name_len)      (((name_len) + 8 + EXT2_DIR_ROUND) & \
536                                          ~EXT2_DIR_ROUND)
537 #define EXT2_MAX_REC_LEN                ((1<<16)-1)
538
539 #define EXT2_SB_MAGIC_OFFSET    0x38
540 #define EXT2_SB_BLOCKS_OFFSET   0x04
541 #define EXT2_SB_BSIZE_OFFSET    0x18
542
543 static inline u64 ext2_image_size(void *ext2_sb)
544 {
545         __u8 *p = ext2_sb;
546         if (*(__le16 *)(p + EXT2_SB_MAGIC_OFFSET) != cpu_to_le16(EXT2_SUPER_MAGIC))
547                 return 0;
548         return (u64)le32_to_cpup((__le32 *)(p + EXT2_SB_BLOCKS_OFFSET)) <<
549                 le32_to_cpup((__le32 *)(p + EXT2_SB_BSIZE_OFFSET));
550 }
551
552 static inline void verify_offsets(void)
553 {
554 #define A(x,y) BUILD_BUG_ON(x != offsetof(struct ext2_super_block, y));
555         A(EXT2_SB_MAGIC_OFFSET, s_magic);
556         A(EXT2_SB_BLOCKS_OFFSET, s_blocks_count);
557         A(EXT2_SB_BSIZE_OFFSET, s_log_block_size);
558 #undef A
559 }
560
561 #endif  /* _LINUX_EXT2_FS_H */