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1.. SPDX-License-Identifier: GPL-2.02 3Special inodes4--------------5 6ext4 reserves some inode for special features, as follows:7 8.. list-table::9 :widths: 6 7010 :header-rows: 111 12 * - inode Number13 - Purpose14 * - 015 - Doesn't exist; there is no inode 0.16 * - 117 - List of defective blocks.18 * - 219 - Root directory.20 * - 321 - User quota.22 * - 423 - Group quota.24 * - 525 - Boot loader.26 * - 627 - Undelete directory.28 * - 729 - Reserved group descriptors inode. (“resize inode”)30 * - 831 - Journal inode.32 * - 933 - The “exclude” inode, for snapshots(?)34 * - 1035 - Replica inode, used for some non-upstream feature?36 * - 1137 - Traditional first non-reserved inode. Usually this is the lost+found directory. See s_first_ino in the superblock.38 39Note that there are also some inodes allocated from non-reserved inode numbers40for other filesystem features which are not referenced from standard directory41hierarchy. These are generally reference from the superblock. They are:42 43.. list-table::44 :widths: 20 5045 :header-rows: 146 47 * - Superblock field48 - Description49 50 * - s_lpf_ino51 - Inode number of lost+found directory.52 * - s_prj_quota_inum53 - Inode number of quota file tracking project quotas54 * - s_orphan_file_inum55 - Inode number of file tracking orphan inodes.56