What features are supported by the ext4 file system?
As of this writing, the ext4 file system supports the following features: • Extended attribute blocks and large inodes (EXT3_FEATURE_COMPAT_EXT_ATTR) • Online filesystem resize reservations (EXT3_FEATURE_COMPAT_RESIZE_INODE) • Hash-indexed directories (EXT3_FEATURE_COMPAT_DIR_INDEX) • Journal file/device present (EXT3_FEATURE_COMPAT_HAS_JOURNAL) (not required for ext4 to mount the filesystem) • File type in directory entries (EXT3_FEATURE_INCOMPAT_FILETYPE) • Journal recovery required (EXT3_FEATURE_INCOMPAT_RECOVER) • Files allocated with extent format (EXT4_FEATURE_INCOMPAT_EXTENTS) • Support for more than 2^32 filesystem blocks (EXT4_FEATURE_INCOMPAT_64BIT) • Flexible block group metadata location (EXT4_FEATURE_INCOMPAT_FLEX_BG) • Reduced block group backups (EXT3_FEATURE_INCOMPAT_META_BG) • Reduced superblock backups (EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER) • Files larger than 2GB in size (EXT3_FEATURE_RO_COMPAT_LARGE_FILE) • Group descriptor checksums and sparse inode table (EXT4_FEAT
