^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) .. SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) Index Nodes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) -----------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) In a regular UNIX filesystem, the inode stores all the metadata
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) pertaining to the file (time stamps, block maps, extended attributes,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) etc), not the directory entry. To find the information associated with a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) file, one must traverse the directory files to find the directory entry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) associated with a file, then load the inode to find the metadata for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) that file. ext4 appears to cheat (for performance reasons) a little bit
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) by storing a copy of the file type (normally stored in the inode) in the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) directory entry. (Compare all this to FAT, which stores all the file
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) information directly in the directory entry, but does not support hard
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) links and is in general more seek-happy than ext4 due to its simpler
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) block allocator and extensive use of linked lists.)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) The inode table is a linear array of ``struct ext4_inode``. The table is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) sized to have enough blocks to store at least
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) ``sb.s_inode_size * sb.s_inodes_per_group`` bytes. The number of the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) block group containing an inode can be calculated as
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) ``(inode_number - 1) / sb.s_inodes_per_group``, and the offset into the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) group's table is ``(inode_number - 1) % sb.s_inodes_per_group``. There
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) is no inode 0.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) The inode checksum is calculated against the FS UUID, the inode number,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) and the inode structure itself.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) The inode table entry is laid out in ``struct ext4_inode``.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) .. list-table::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) :widths: 8 8 24 40
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) :header-rows: 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) :class: longtable
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) * - Offset
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) - Size
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) - Name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) - Description
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) * - 0x0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) - \_\_le16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) - i\_mode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) - File mode. See the table i_mode_ below.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) * - 0x2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) - \_\_le16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) - i\_uid
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) - Lower 16-bits of Owner UID.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) * - 0x4
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) - i\_size\_lo
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) - Lower 32-bits of size in bytes.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) * - 0x8
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) - i\_atime
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) - Last access time, in seconds since the epoch. However, if the EA\_INODE
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) inode flag is set, this inode stores an extended attribute value and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) this field contains the checksum of the value.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) * - 0xC
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) - i\_ctime
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) - Last inode change time, in seconds since the epoch. However, if the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) EA\_INODE inode flag is set, this inode stores an extended attribute
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) value and this field contains the lower 32 bits of the attribute value's
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) reference count.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) * - 0x10
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) - i\_mtime
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) - Last data modification time, in seconds since the epoch. However, if the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) EA\_INODE inode flag is set, this inode stores an extended attribute
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) value and this field contains the number of the inode that owns the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) extended attribute.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) * - 0x14
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) - i\_dtime
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) - Deletion Time, in seconds since the epoch.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) * - 0x18
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) - \_\_le16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) - i\_gid
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) - Lower 16-bits of GID.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) * - 0x1A
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) - \_\_le16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) - i\_links\_count
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) - Hard link count. Normally, ext4 does not permit an inode to have more
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) than 65,000 hard links. This applies to files as well as directories,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) which means that there cannot be more than 64,998 subdirectories in a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) directory (each subdirectory's '..' entry counts as a hard link, as does
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) the '.' entry in the directory itself). With the DIR\_NLINK feature
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) enabled, ext4 supports more than 64,998 subdirectories by setting this
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) field to 1 to indicate that the number of hard links is not known.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) * - 0x1C
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) - i\_blocks\_lo
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) - Lower 32-bits of “block” count. If the huge\_file feature flag is not
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) set on the filesystem, the file consumes ``i_blocks_lo`` 512-byte blocks
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) on disk. If huge\_file is set and EXT4\_HUGE\_FILE\_FL is NOT set in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) ``inode.i_flags``, then the file consumes ``i_blocks_lo + (i_blocks_hi
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) << 32)`` 512-byte blocks on disk. If huge\_file is set and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) EXT4\_HUGE\_FILE\_FL IS set in ``inode.i_flags``, then this file
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) consumes (``i_blocks_lo + i_blocks_hi`` << 32) filesystem blocks on
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) disk.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) * - 0x20
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) - i\_flags
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) - Inode flags. See the table i_flags_ below.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) * - 0x24
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) - 4 bytes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) - i\_osd1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) - See the table i_osd1_ for more details.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) * - 0x28
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) - 60 bytes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) - i\_block[EXT4\_N\_BLOCKS=15]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) - Block map or extent tree. See the section “The Contents of inode.i\_block”.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) * - 0x64
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) - i\_generation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) - File version (for NFS).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) * - 0x68
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) - i\_file\_acl\_lo
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) - Lower 32-bits of extended attribute block. ACLs are of course one of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) many possible extended attributes; I think the name of this field is a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) result of the first use of extended attributes being for ACLs.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) * - 0x6C
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) - i\_size\_high / i\_dir\_acl
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) - Upper 32-bits of file/directory size. In ext2/3 this field was named
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) i\_dir\_acl, though it was usually set to zero and never used.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) * - 0x70
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) - i\_obso\_faddr
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) - (Obsolete) fragment address.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) * - 0x74
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) - 12 bytes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) - i\_osd2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) - See the table i_osd2_ for more details.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) * - 0x80
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) - \_\_le16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) - i\_extra\_isize
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) - Size of this inode - 128. Alternately, the size of the extended inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) fields beyond the original ext2 inode, including this field.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) * - 0x82
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) - \_\_le16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) - i\_checksum\_hi
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) - Upper 16-bits of the inode checksum.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) * - 0x84
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) - i\_ctime\_extra
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) - Extra change time bits. This provides sub-second precision. See Inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) Timestamps section.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) * - 0x88
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) - i\_mtime\_extra
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) - Extra modification time bits. This provides sub-second precision.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) * - 0x8C
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) - i\_atime\_extra
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) - Extra access time bits. This provides sub-second precision.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) * - 0x90
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) - i\_crtime
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) - File creation time, in seconds since the epoch.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) * - 0x94
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) - i\_crtime\_extra
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) - Extra file creation time bits. This provides sub-second precision.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) * - 0x98
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) - i\_version\_hi
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) - Upper 32-bits for version number.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) * - 0x9C
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) - i\_projid
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) - Project ID.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) .. _i_mode:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) The ``i_mode`` value is a combination of the following flags:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) .. list-table::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) :widths: 16 64
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) :header-rows: 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) * - Value
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) - Description
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) * - 0x1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) - S\_IXOTH (Others may execute)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) * - 0x2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) - S\_IWOTH (Others may write)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) * - 0x4
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) - S\_IROTH (Others may read)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) * - 0x8
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) - S\_IXGRP (Group members may execute)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) * - 0x10
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) - S\_IWGRP (Group members may write)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) * - 0x20
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) - S\_IRGRP (Group members may read)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) * - 0x40
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) - S\_IXUSR (Owner may execute)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) * - 0x80
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) - S\_IWUSR (Owner may write)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) * - 0x100
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) - S\_IRUSR (Owner may read)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) * - 0x200
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) - S\_ISVTX (Sticky bit)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) * - 0x400
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) - S\_ISGID (Set GID)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) * - 0x800
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) - S\_ISUID (Set UID)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) * -
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) - These are mutually-exclusive file types:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) * - 0x1000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) - S\_IFIFO (FIFO)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) * - 0x2000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) - S\_IFCHR (Character device)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) * - 0x4000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) - S\_IFDIR (Directory)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) * - 0x6000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) - S\_IFBLK (Block device)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) * - 0x8000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) - S\_IFREG (Regular file)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) * - 0xA000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) - S\_IFLNK (Symbolic link)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) * - 0xC000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) - S\_IFSOCK (Socket)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) .. _i_flags:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) The ``i_flags`` field is a combination of these values:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) .. list-table::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) :widths: 16 64
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) :header-rows: 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) * - Value
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) - Description
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) * - 0x1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) - This file requires secure deletion (EXT4\_SECRM\_FL). (not implemented)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) * - 0x2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) - This file should be preserved, should undeletion be desired
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) (EXT4\_UNRM\_FL). (not implemented)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) * - 0x4
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) - File is compressed (EXT4\_COMPR\_FL). (not really implemented)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) * - 0x8
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) - All writes to the file must be synchronous (EXT4\_SYNC\_FL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) * - 0x10
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) - File is immutable (EXT4\_IMMUTABLE\_FL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) * - 0x20
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) - File can only be appended (EXT4\_APPEND\_FL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) * - 0x40
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) - The dump(1) utility should not dump this file (EXT4\_NODUMP\_FL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) * - 0x80
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) - Do not update access time (EXT4\_NOATIME\_FL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) * - 0x100
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) - Dirty compressed file (EXT4\_DIRTY\_FL). (not used)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) * - 0x200
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) - File has one or more compressed clusters (EXT4\_COMPRBLK\_FL). (not used)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) * - 0x400
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) - Do not compress file (EXT4\_NOCOMPR\_FL). (not used)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) * - 0x800
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) - Encrypted inode (EXT4\_ENCRYPT\_FL). This bit value previously was
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) EXT4\_ECOMPR\_FL (compression error), which was never used.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) * - 0x1000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) - Directory has hashed indexes (EXT4\_INDEX\_FL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) * - 0x2000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) - AFS magic directory (EXT4\_IMAGIC\_FL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) * - 0x4000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) - File data must always be written through the journal
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) (EXT4\_JOURNAL\_DATA\_FL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) * - 0x8000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) - File tail should not be merged (EXT4\_NOTAIL\_FL). (not used by ext4)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) * - 0x10000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) - All directory entry data should be written synchronously (see
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) ``dirsync``) (EXT4\_DIRSYNC\_FL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) * - 0x20000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) - Top of directory hierarchy (EXT4\_TOPDIR\_FL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) * - 0x40000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) - This is a huge file (EXT4\_HUGE\_FILE\_FL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) * - 0x80000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) - Inode uses extents (EXT4\_EXTENTS\_FL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) * - 0x100000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) - Verity protected file (EXT4\_VERITY\_FL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) * - 0x200000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) - Inode stores a large extended attribute value in its data blocks
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) (EXT4\_EA\_INODE\_FL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) * - 0x400000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) - This file has blocks allocated past EOF (EXT4\_EOFBLOCKS\_FL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) (deprecated)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) * - 0x01000000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) - Inode is a snapshot (``EXT4_SNAPFILE_FL``). (not in mainline)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) * - 0x04000000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) - Snapshot is being deleted (``EXT4_SNAPFILE_DELETED_FL``). (not in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) mainline)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) * - 0x08000000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) - Snapshot shrink has completed (``EXT4_SNAPFILE_SHRUNK_FL``). (not in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) mainline)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) * - 0x10000000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) - Inode has inline data (EXT4\_INLINE\_DATA\_FL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) * - 0x20000000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) - Create children with the same project ID (EXT4\_PROJINHERIT\_FL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) * - 0x80000000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) - Reserved for ext4 library (EXT4\_RESERVED\_FL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) * -
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) - Aggregate flags:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) * - 0x705BDFFF
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) - User-visible flags.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) * - 0x604BC0FF
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) - User-modifiable flags. Note that while EXT4\_JOURNAL\_DATA\_FL and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) EXT4\_EXTENTS\_FL can be set with setattr, they are not in the kernel's
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) EXT4\_FL\_USER\_MODIFIABLE mask, since it needs to handle the setting of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) these flags in a special manner and they are masked out of the set of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) flags that are saved directly to i\_flags.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) .. _i_osd1:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) The ``osd1`` field has multiple meanings depending on the creator:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) Linux:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) .. list-table::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) :widths: 8 8 24 40
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) :header-rows: 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) * - Offset
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) - Size
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) - Name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) - Description
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) * - 0x0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) - l\_i\_version
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) - Inode version. However, if the EA\_INODE inode flag is set, this inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) stores an extended attribute value and this field contains the upper 32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) bits of the attribute value's reference count.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) Hurd:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) .. list-table::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) :widths: 8 8 24 40
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) :header-rows: 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) * - Offset
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) - Size
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) - Name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) - Description
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) * - 0x0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) - h\_i\_translator
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) - ??
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) Masix:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) .. list-table::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) :widths: 8 8 24 40
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) :header-rows: 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) * - Offset
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) - Size
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) - Name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) - Description
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359) * - 0x0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) - \_\_le32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361) - m\_i\_reserved
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362) - ??
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364) .. _i_osd2:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366) The ``osd2`` field has multiple meanings depending on the filesystem creator:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368) Linux:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) .. list-table::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371) :widths: 8 8 24 40
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) :header-rows: 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) * - Offset
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 375) - Size
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 376) - Name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 377) - Description
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 378) * - 0x0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 379) - \_\_le16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 380) - l\_i\_blocks\_high
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 381) - Upper 16-bits of the block count. Please see the note attached to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 382) i\_blocks\_lo.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 383) * - 0x2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 384) - \_\_le16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 385) - l\_i\_file\_acl\_high
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 386) - Upper 16-bits of the extended attribute block (historically, the file
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 387) ACL location). See the Extended Attributes section below.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 388) * - 0x4
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 389) - \_\_le16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 390) - l\_i\_uid\_high
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 391) - Upper 16-bits of the Owner UID.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 392) * - 0x6
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 393) - \_\_le16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 394) - l\_i\_gid\_high
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 395) - Upper 16-bits of the GID.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 396) * - 0x8
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 397) - \_\_le16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 398) - l\_i\_checksum\_lo
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 399) - Lower 16-bits of the inode checksum.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 400) * - 0xA
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 401) - \_\_le16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 402) - l\_i\_reserved
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 403) - Unused.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 404)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 405) Hurd:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 406)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 407) .. list-table::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 408) :widths: 8 8 24 40
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 409) :header-rows: 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 410)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 411) * - Offset
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 412) - Size
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 413) - Name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 414) - Description
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 415) * - 0x0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 416) - \_\_le16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 417) - h\_i\_reserved1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 418) - ??
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 419) * - 0x2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 420) - \_\_u16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 421) - h\_i\_mode\_high
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 422) - Upper 16-bits of the file mode.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 423) * - 0x4
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 424) - \_\_le16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 425) - h\_i\_uid\_high
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 426) - Upper 16-bits of the Owner UID.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 427) * - 0x6
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 428) - \_\_le16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 429) - h\_i\_gid\_high
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 430) - Upper 16-bits of the GID.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 431) * - 0x8
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 432) - \_\_u32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 433) - h\_i\_author
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 434) - Author code?
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 435)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 436) Masix:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 437)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 438) .. list-table::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 439) :widths: 8 8 24 40
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 440) :header-rows: 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 441)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 442) * - Offset
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 443) - Size
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 444) - Name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 445) - Description
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 446) * - 0x0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 447) - \_\_le16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 448) - h\_i\_reserved1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 449) - ??
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 450) * - 0x2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 451) - \_\_u16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 452) - m\_i\_file\_acl\_high
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 453) - Upper 16-bits of the extended attribute block (historically, the file
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 454) ACL location).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 455) * - 0x4
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 456) - \_\_u32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 457) - m\_i\_reserved2[2]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 458) - ??
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 459)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 460) Inode Size
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 461) ~~~~~~~~~~
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 462)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 463) In ext2 and ext3, the inode structure size was fixed at 128 bytes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 464) (``EXT2_GOOD_OLD_INODE_SIZE``) and each inode had a disk record size of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 465) 128 bytes. Starting with ext4, it is possible to allocate a larger
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 466) on-disk inode at format time for all inodes in the filesystem to provide
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 467) space beyond the end of the original ext2 inode. The on-disk inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 468) record size is recorded in the superblock as ``s_inode_size``. The
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 469) number of bytes actually used by struct ext4\_inode beyond the original
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 470) 128-byte ext2 inode is recorded in the ``i_extra_isize`` field for each
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 471) inode, which allows struct ext4\_inode to grow for a new kernel without
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 472) having to upgrade all of the on-disk inodes. Access to fields beyond
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 473) EXT2\_GOOD\_OLD\_INODE\_SIZE should be verified to be within
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 474) ``i_extra_isize``. By default, ext4 inode records are 256 bytes, and (as
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 475) of August 2019) the inode structure is 160 bytes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 476) (``i_extra_isize = 32``). The extra space between the end of the inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 477) structure and the end of the inode record can be used to store extended
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 478) attributes. Each inode record can be as large as the filesystem block
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 479) size, though this is not terribly efficient.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 480)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 481) Finding an Inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 482) ~~~~~~~~~~~~~~~~
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 483)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 484) Each block group contains ``sb->s_inodes_per_group`` inodes. Because
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 485) inode 0 is defined not to exist, this formula can be used to find the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 486) block group that an inode lives in:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 487) ``bg = (inode_num - 1) / sb->s_inodes_per_group``. The particular inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 488) can be found within the block group's inode table at
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 489) ``index = (inode_num - 1) % sb->s_inodes_per_group``. To get the byte
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 490) address within the inode table, use
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 491) ``offset = index * sb->s_inode_size``.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 492)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 493) Inode Timestamps
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 494) ~~~~~~~~~~~~~~~~
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 495)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 496) Four timestamps are recorded in the lower 128 bytes of the inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 497) structure -- inode change time (ctime), access time (atime), data
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 498) modification time (mtime), and deletion time (dtime). The four fields
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 499) are 32-bit signed integers that represent seconds since the Unix epoch
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 500) (1970-01-01 00:00:00 GMT), which means that the fields will overflow in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 501) January 2038. For inodes that are not linked from any directory but are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 502) still open (orphan inodes), the dtime field is overloaded for use with
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 503) the orphan list. The superblock field ``s_last_orphan`` points to the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 504) first inode in the orphan list; dtime is then the number of the next
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 505) orphaned inode, or zero if there are no more orphans.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 506)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 507) If the inode structure size ``sb->s_inode_size`` is larger than 128
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 508) bytes and the ``i_inode_extra`` field is large enough to encompass the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 509) respective ``i_[cma]time_extra`` field, the ctime, atime, and mtime
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 510) inode fields are widened to 64 bits. Within this “extra” 32-bit field,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 511) the lower two bits are used to extend the 32-bit seconds field to be 34
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 512) bit wide; the upper 30 bits are used to provide nanosecond timestamp
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 513) accuracy. Therefore, timestamps should not overflow until May 2446.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 514) dtime was not widened. There is also a fifth timestamp to record inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 515) creation time (crtime); this field is 64-bits wide and decoded in the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 516) same manner as 64-bit [cma]time. Neither crtime nor dtime are accessible
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 517) through the regular stat() interface, though debugfs will report them.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 518)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 519) We use the 32-bit signed time value plus (2^32 \* (extra epoch bits)).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 520) In other words:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 521)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 522) .. list-table::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 523) :widths: 20 20 20 20 20
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 524) :header-rows: 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 525)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 526) * - Extra epoch bits
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 527) - MSB of 32-bit time
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 528) - Adjustment for signed 32-bit to 64-bit tv\_sec
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 529) - Decoded 64-bit tv\_sec
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 530) - valid time range
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 531) * - 0 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 532) - 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 533) - 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 534) - ``-0x80000000 - -0x00000001``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 535) - 1901-12-13 to 1969-12-31
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 536) * - 0 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 537) - 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 538) - 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 539) - ``0x000000000 - 0x07fffffff``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 540) - 1970-01-01 to 2038-01-19
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 541) * - 0 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 542) - 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 543) - 0x100000000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 544) - ``0x080000000 - 0x0ffffffff``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 545) - 2038-01-19 to 2106-02-07
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 546) * - 0 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 547) - 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 548) - 0x100000000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 549) - ``0x100000000 - 0x17fffffff``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 550) - 2106-02-07 to 2174-02-25
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 551) * - 1 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 552) - 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 553) - 0x200000000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 554) - ``0x180000000 - 0x1ffffffff``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 555) - 2174-02-25 to 2242-03-16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 556) * - 1 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 557) - 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 558) - 0x200000000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 559) - ``0x200000000 - 0x27fffffff``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 560) - 2242-03-16 to 2310-04-04
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 561) * - 1 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 562) - 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 563) - 0x300000000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 564) - ``0x280000000 - 0x2ffffffff``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 565) - 2310-04-04 to 2378-04-22
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 566) * - 1 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 567) - 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 568) - 0x300000000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 569) - ``0x300000000 - 0x37fffffff``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 570) - 2378-04-22 to 2446-05-10
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 571)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 572) This is a somewhat odd encoding since there are effectively seven times
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 573) as many positive values as negative values. There have also been
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 574) long-standing bugs decoding and encoding dates beyond 2038, which don't
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 575) seem to be fixed as of kernel 3.12 and e2fsprogs 1.42.8. 64-bit kernels
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 576) incorrectly use the extra epoch bits 1,1 for dates between 1901 and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 577) 1970. At some point the kernel will be fixed and e2fsck will fix this
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 578) situation, assuming that it is run before 2310.
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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