EXT4(5) File Formats Manual EXT4(5) ext2 - ext3 - ext4 - ext2 ext3 ext4 . . ext2 ext3 ext4 ext4 ext2 ext3. ext2 ext3 ext4 . ext2 ext3 ext4 . GNU/HURD FreeBSD ext2. 64bit 2^32 . 2^32 . e2fsprogs ext4 . bigalloc ext4 . 16 . . mke2fs -C. : bigalloc . http://ext4.wiki.kernel.org/index.php/Bigalloc . ( nodelalloc). extent. casefold ext4 casefold (+F). . dir_index b . ext3 ext4 ext2. dir_nlink ext4 (inode) 65,000 . 64,998 ( '.' '..' ). ext4 1 . ea_inode . . encrypt . ( / ) . . dm-crypt . ext_attr . ext2 ext3 ext4. extent ext4 (extent tree) ext2 ext3. e2fsck(8) . (: extent extents /). extra_isize ext4 . . 256 . filetype . ext2 ext3 ext4. flex_bg ext4 ( ) . mke2fs(8) " flex_bg". flex_bg -G. has_journal . -j mke2fs(8) tune2fs(8). ext3 ext4 ext2. huge_file ext4 2 . inline_data . journal_dev (superblock) . . -J device= mke2fs(8) tune2fs(8). large_dir b ( dir_index) b . large_file 2 . . metadata_csum ext4 . ( ). uninit_bg. metadata_csum uninit_bg. metadata_csum_seed UUID metadata_csum . meta_bg ext4 . 2^32 . . mmp ext4 (MMP). MMP . orphan_file ext4 . 5.15 e2fsprogs 1.47.0. project ext4 . . quota ( 3 4 ) . . ( user.quota group.quota ) . resize_inode . resize2fs(8). mke2fs(8) 1024 . resize . sparse_super sparse_super2. sparse_super ext2 ext3 ext4. . sparse_super2 . 1 . sparse_super . stable_inodes UUID . resize2fs(8) tune2fs(8) UUID . UUID. encrypt . stable_inodes "compat" . uninit_bg ext4 mke2fs(8) . . e2fsck(8) mke2fs(8) . verity (verity). Merkle . Merkle . . dm-verity . ext2 ext3 ext4. mount(8) . ext2 ext2 . 2.5.46 . tune2fs(8). acl | noacl POSIX ( ). acl(5). bsddf | minixdf statfs. minixdf f_blocks bsddf ( ) ext2 . % mount /k -o minixdf; df /k; umount /k 1024-blocks Used Available Capacity Mounted on /dev/sda6 2630655 86954 2412169 3% /k % mount /k -o bsddf; df /k; umount /k 1024-blocks Used Available Capacity Mounted on /dev/sda6 2543714 13 2412169 0% /k ( /etc/fstab.) check=none | nocheck . . . e2fsck(8) . ( check=normal check=strict). ext4 ext2 ext3. debug ( ). errors={continue|remount-ro|panic} . ( ). tune2fs(8). grpid | bsdgroups nogrpid | sysvgroups . grpid () fsgid setgid gid setgid . grpquota | usrquota | quota | noquota usrquota ( quota) . grpquota . quota(1) . nouid32 (UIDs) (GIDs) 32 . 16 . oldalloc | orlov (Orlov) . . resgid=n and resuid=n ext2 ( 5% mke2fs(8) tune2fs(8). . (: uid ). sb=n n. . sparse_super. mke2fs(8) -n mke2fs(8) ( sparse_super ). 1 k. 32768 4 k "sb=131072". user_xattr | nouser_xattr ".user" ( ). ext3 ext3 ext2 . ext2 : journal_dev=devnum | journal_path=path / . / devnum . norecovery | noload . . data={journal|ordered|writeback} . . ordered rootflags=data=journal. journal . ordered . . writeback - . . . data_err={abort|ignore} (ordered): data_err=abort . data_err=ignore . barrier={0|1} jbd. barrier=0 barrier=1 (). / jbd . . . commit=nrsec nrsec . 5 . . user_xattr . attr(5). jqfmt={vfsold|vfsv0|vfsv1} ( ext2 jqfmt=vfsold 1) ext3 ( 2). jqfmt=vfsv0 jqfmt=vfsv1 . . quota . usrjquota=aquota.user | grpjquota=aquota.group (jqfmt=vfsv0 jqfmt=vfsv1) usrjquota=aquota.user grpjquota=aquota.group . quota . ext4 ext4 ext3 . journal_dev journal_path norecovery noload data commit orlov oldalloc [no]user_xattr [no]acl bsddf minixdf debug errors data_err grpid bsdgroups nogrpid sysvgroups resgid resuid sb quota noquota nouid32 grpquota usrquota usrjquota grpjquota jqfmt ext3 ext2. journal_checksum | nojournal_checksum journal_checksum . e2fsck(8) . . journal_async_commit . . journal_checksum . barrier={0|1} | barrier | nobarrier ext3. barrier nobarrier ext4 . ext4 . inode_readahead_blks=n ext4 . 2. 32 . stripe=n mballoc . RAID5/6 * RAID . delalloc . nodelalloc . . max_batch_time=max_usec ext4 . / . ( ) . " ". ext4 . max_usec 15000 s (15 ). max_batch_time=0. min_batch_time=min_usec ( ) min_usec. . . journal_ioprio=prio / ( 0 7 0 ) / kjournald2 . 3 / . ext4_abort() . . auto_da_alloc | noauto_da_alloc fsync() fd = open("foo.new")/write(fd,...)/close(fd)/ rename("foo.new", "foo") fd = open("foo", O_TRUNC)/write(fd,...)/close(fd). auto_da_alloc ext4 rename() data=ordered . ext3 " " . noinit_itable . . init_itable=n itable n . . discard | nodiscard ext4 /TRIM . SSD LUN / . block_validity | noblock_validity / . . . dioread_lock | dioread_nolock ext4 DIO . dioread_nolock ext4 /. ext4 . dioread_nolock . dioread_nolock . ( dioread_lock). max_dir_size_kb=n ENOSPC. . ( 512 MiB 176 MiB .) i_version 64-. . nombcache mbcache . mbcache . prjquota . quota(1) . project. ext2 ext3 ext4 chattr(1): a - A - atime d - D - i - S - u - ext3 ext4 : j - ext4 : e - chattr(1). ( ext2 ext3 ext4) . . . " " . filetype ext2 2.2.0 sparse_super ext2 2.2.0 large_file ext2 2.2.0 has_journal ext3 2.4.15 ext_attr ext2/ext3 2.6.0 dir_index ext3 2.6.0 resize_inode ext3 2.6.10 ( ) 64bit ext4 2.6.28 dir_nlink ext4 2.6.28 extent ext4 2.6.28 extra_isize ext4 2.6.28 flex_bg ext4 2.6.28 huge_file ext4 2.6.28 meta_bg ext4 2.6.28 uninit_bg ext4 2.6.28 mmp ext4 3.0 bigalloc ext4 3.2 quota ext4 3.6 inline_data ext4 3.8 sparse_super2 ext4 3.16 metadata_csum ext4 3.18 encrypt ext4 4.1 metadata_csum_seed ext4 4.4 project ext4 4.5 ea_inode ext4 4.13 large_dir ext4 4.13 casefold ext4 5.2 verity ext4 5.4 stable_inodes ext4 5.5 fast_commit ext4 5.10 orphan_file ext4 5.15 mke2fs(8), mke2fs.conf(5), e2fsck(8), dumpe2fs(8), tune2fs(8), debugfs(8), mount(8), chattr(1) 3 . . : . E2fsprogs 1.47.4 2025 EXT4(5)