xattr(7) Miscellaneous Information Manual xattr(7) xattr - :, , . . , , . Extended attributes are extensions to the normal attributes which are associated with all inodes in the system (i.e., the stat(2) data). They are often used to provide additional functionality to a filesystem--for example, additional security features such as Access Control Lists (ACLs) may be implemented using extended attributes. , listxattr(2) , . . (getxattr(2)) . (setxattr(2)) . . null . -- _., , user.mime_type, trusted.md5sum, system.posix_acl_access security.selinux. . ; , , , . : security, system, trusted user. . , Security Enhanced Linux, ( capabilities(7)). , . , , CAP_SYS_ADMIN. , . , . CAP_SYS_ADMIN. (. ., ) , . , mime, . : , . . , , . . , . , ( chmod(1)). The kernel and the filesystem may place limits on the maximum number and size of extended attributes that can be associated with a file. The VFS-imposed limits on attribute names and values are 255 bytes and 64 kB, respectively. The list of attribute names that can be returned is also limited to 64 kB (see BUGS in listxattr(2)). , Reiserfs (, , ext2 ext3), , user_xattr. ext2, ext3 ext4 , , (1024, 2048 4096 , , ). Btrfs, XFS Reiserfs , , . JFS, XFS Reiserfs , EA, VFS. Btrfs , , , nodesize ( 16 ). POSIX.1, (, BSD Solaris) . , , , , - . attr(5). . attr(1), getfattr(1), setfattr(1), getxattr(2), ioctl_iflags(2), listxattr(2), removexattr(2), setxattr(2), acl(5), capabilities(7), selinux(8) Azamat Hackimov , Yuri Kozlov ; GNU 3 , . . , , . Linux man-pages 6.06 31 2023 . xattr(7)