SA - linux文件系统管理杂项(1)

[root@CentOS6 mnt]# touch /mnt/my_hd
[root@CentOS6 mnt]# dd if=/dev/zero of=/mnt/my_hd bs=8192 count=10
[root@CentOS6 mnt]# losetup /dev/loop0 /mnt/my_hd
[root@CentOS6 mnt]# mkfs.ext4 /dev/loop0
[root@CentOS6 mnt]# mount /dev/loop0 /mnt/vdisk
[root@CentOS6 mnt]# cd /mnt/vdisk;ls -al
...
drwx------ 2 root root 12288 Sep 19 21:04 lost+found

[root@CentOS6 mnt]# mount --bind /home/one/.bash_profile /home/two/.bash_profile

[root@CentOS6 mnt]# touch /home/two/bind.txt
[root@CentOS6 mnt]# mount --bind /home/two/bind.txt /home/one/bind.txt
[root@CentOS6 ~]# chown two /home/two/bind.txt

这样我们就创建了一个two拥有修改权限的bind.txt文件，而这个文件在one上也可以读，但是不
可以修改。

[root@CentOS6 ~]# mv /home/two/bind.txt /home/two/bind.txt.bak
[root@CentOS6 ~]# cat /home/one/bind.txt
two

就算将这个文件移除，镜像者仍然保存历史镜像，且镜像者可以修改这个文件了：

[root@CentOS6 ~]# echo one >> /home/one/bind.txt
[root@CentOS6 ~]# cat /home/one/bind.txt
two
one

【--bind】机制：如果有源，则使用此文件镜像；如果没有，则使用镜像者本身
实体文件。

【--bind】权限问题

[two@CentOS6 ~]$ touch acl.mirror
[two@CentOS6 ~]$ chmod a+x acl.mirror
[two@CentOS6 ~]$ setfacl -m user:root:rwx acl.mirror
[two@CentOS6 ~]$ getfacl acl.mirror
# file: acl.mirror
# owner: two
# group: two
user::rwx
user:root:rwx
group::rwx
mask::rwx
other::r-x

[root@CentOS6 ~]# touch /home/one/acl.mirror
[root@CentOS6 ~]# mount --bind /home/two/acl.mirror /home/one/acl.mirror
[root@CentOS6 ~]# ls -l /home/one/acl.mirror /home/two/acl.mirror
-rwxrwxr-x+ 1 two two 0 Sep 19 21:33 /home/one/acl.mirror
-rwxrwxr-x+ 1 two two 0 Sep 19 21:33 /home/two/acl.mirror
[root@CentOS6 ~]# mount --bind /home/one/acl.mirror /home/two/acl.mirror
[root@CentOS6 ~]# ls -l /home/one/acl.mirror /home/two/acl.mirror
-rwxrwxr-x+ 1 two two 0 Sep 19 21:33 /home/one/acl.mirror
-rwxrwxr-x+ 1 two two 0 Sep 19 21:33 /home/two/acl.mirror
[root@CentOS6 ~]# umount /home/one/acl.mirror
[root@CentOS6 ~]# umount /home/two/acl.mirror
[root@CentOS6 ~]# mount --bind /home/one/acl.mirror /home/two/acl.mirror
[root@CentOS6 ~]# ls -l /home/one/acl.mirror /home/two/acl.mirror
-rw-r--r-- 1 root root 0 Sep 19 21:35 /home/one/acl.mirror
-rw-r--r-- 1 root root 0 Sep 19 21:35 /home/two/acl.mirror

[root@CentOS6 ~]# mv /home/one/acl.mirror /home/one/acl.mirror.bak
[root@CentOS6 ~]# ll /home/two/acl.mirror
-rw-r--r-- 1 root root 0 Sep 19 21:35 /home/two/acl.mirror
[root@CentOS6 ~]# umount /home/one/acl.mirror
[root@CentOS6 ~]# ll /home/two/acl.mirror
-rwxrwxr-x+ 1 two two 0 Sep 19 21:33 /home/two/acl.mirror

在绑定期间，镜像拥有所有源权限。

restorecon -R递归恢复selinux context上下文。