5 * The second extended file system magic number
7 #define EXT3_SUPER_MAGIC 0xEF53
9 #define EXT2_FLAGS_TEST_FILESYS 0x0004
10 #define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001
11 #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE 0x0002
12 #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR 0x0004
13 #define EXT2_FEATURE_INCOMPAT_FILETYPE 0x0002
14 #define EXT2_FEATURE_INCOMPAT_META_BG 0x0010
15 #define EXT3_FEATURE_COMPAT_HAS_JOURNAL 0x0004
16 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV 0x0008
17 #define EXT3_FEATURE_INCOMPAT_RECOVER 0x0004
19 #define EXT3_FEATURE_INCOMPAT_EXTENTS 0x0040
20 #define EXT4_FEATURE_INCOMPAT_64BIT 0x0080
21 #define EXT4_FEATURE_INCOMPAT_MMP 0x0100
23 #define EXT3_FEATURE_RO_COMPAT_SUPP (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
24 EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
25 EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
26 #define EXT3_FEATURE_RO_COMPAT_UNSUPPORTED ~EXT3_FEATURE_RO_COMPAT_SUPP
27 #define EXT3_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE| \
28 EXT3_FEATURE_INCOMPAT_RECOVER| \
29 EXT2_FEATURE_INCOMPAT_META_BG)
30 #define EXT3_FEATURE_INCOMPAT_UNSUPPORTED ~EXT3_FEATURE_INCOMPAT_SUPP
35 * Structure of the super block
37 struct ext3_super_block
{
38 /*00*/ __u32 s_inodes_count
;
40 __u32 s_blocks_count
; /* Blocks count */
41 __u32 s_r_blocks_count
; /* Reserved blocks count */
42 __u32 s_free_blocks_count
; /* Free blocks count */
43 /*10*/ __u32 s_free_inodes_count
;
44 /* Free inodes count */
45 __u32 s_first_data_block
; /* First Data Block */
46 __u32 s_log_block_size
; /* Block size */
47 __s32 s_log_frag_size
; /* Fragment size */
48 /*20*/ __u32 s_blocks_per_group
;
49 /* # Blocks per group */
50 __u32 s_frags_per_group
; /* # Fragments per group */
51 __u32 s_inodes_per_group
; /* # Inodes per group */
52 __u32 s_mtime
; /* Mount time */
55 __u16 s_mnt_count
; /* Mount count */
56 __s16 s_max_mnt_count
; /* Maximal mount count */
57 __u16 s_magic
; /* Magic signature */
58 __u16 s_state
; /* File system state */
59 __u16 s_errors
; /* Behaviour when detecting errors */
60 __u16 s_minor_rev_level
; /* minor revision level */
61 /*40*/ __u32 s_lastcheck
;
62 /* time of last check */
63 __u32 s_checkinterval
; /* max. time between checks */
64 __u32 s_creator_os
; /* OS */
65 __u32 s_rev_level
; /* Revision level */
66 /*50*/ __u16 s_def_resuid
;
67 /* Default uid for reserved blocks */
68 __u16 s_def_resgid
; /* Default gid for reserved blocks */
70 * These fields are for EXT3_DYNAMIC_REV superblocks only.
72 * Note: the difference between the compatible feature set and
73 * the incompatible feature set is that if there is a bit set
74 * in the incompatible feature set that the kernel doesn't
75 * know about, it should refuse to mount the filesystem.
77 * e2fsck's requirements are more strict; if it doesn't know
78 * about a feature in either the compatible or incompatible
79 * feature set, it must abort and not try to meddle with
80 * things it doesn't understand...
82 __u32 s_first_ino
; /* First non-reserved inode */
83 __u16 s_inode_size
; /* size of inode structure */
84 __u16 s_block_group_nr
; /* block group # of this superblock */
85 __u32 s_feature_compat
; /* compatible feature set */
86 /*60*/ __u32 s_feature_incompat
;
87 /* incompatible feature set */
88 __u32 s_feature_ro_compat
; /* readonly-compatible feature set */
89 /*68*/ __u8 s_uuid
[16];
90 /* 128-bit uuid for volume */
91 /*78*/ char s_volume_name
[16];
93 /*88*/ char s_last_mounted
[64];
94 /* directory where last mounted */
95 /*C8*/ __u32 s_algorithm_usage_bitmap
;
98 * Performance hints. Directory preallocation should only
99 * happen if the EXT3_FEATURE_COMPAT_DIR_PREALLOC flag is on.
101 __u8 s_prealloc_blocks
; /* Nr of blocks to try to preallocate */
102 __u8 s_prealloc_dir_blocks
; /* Nr to preallocate for dirs */
105 * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
107 /*D0*/ __u8 s_journal_uuid
[16];
108 /* uuid of journal superblock */
109 /*E0*/ __u32 s_journal_inum
;
110 /* inode number of journal file */
111 __u32 s_journal_dev
; /* device number of journal file */
112 __u32 s_last_orphan
; /* start of list of inodes to delete */
113 __u32 s_hash_seed
[4]; /* HTREE hash seed */
114 __u8 s_def_hash_version
; /* Default hash version to use */
115 __u8 s_jnl_backup_type
;
116 __u16 s_reserved_word_pad
;
117 __u32 s_default_mount_opts
;
118 __u32 s_first_meta_bg
;
120 __u32 s_jnl_blocks
[17];
121 __u32 s_blocks_count_hi
;
122 __u32 s_r_blocks_count_hi
;
123 __u32 s_free_blocks_hi
;
124 __u16 s_min_extra_isize
;
125 __u16 s_want_extra_isize
;
128 __u16 s_mmp_interval
;
130 __u32 s_raid_stripe_width
;
131 __u32 s_reserved
[163];
134 #endif /* __EXT3_FS_H */