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加大 LUKS 分割區

查看目前分割區，根目錄使用 /dev/sda2 LUKS 加密，要將 /dev/sda3 併入 LUKS k加密分割區。

[root@localhost ~]# lsblk 
NAME                                   MAJ:MIN RM  SIZE RO TYPE  MOUNTPOINT
sda                                      8:0    0 18.4G  0 disk  
├─sda1                                   8:1    0  400M  0 part  /boot
├─sda2                                   8:2    0   10G  0 part  
│ └─luks-b22f30aa-72d7-4523-aa21-dc516da53fc8
                                       253:0    0   10G  0 crypt /
├─sda3                                   8:3    0    4G  0 part  
├─sda4                                   8:4    0    1K  0 part  
├─sda5                                   8:5    0  500M  0 part  [SWAP]
└─sda6                                   8:6    0   10M  0 part  
sr0                                     11:0    1 55.3M  0 rom

GUEST fdisk 刪除 /dev/sda2 及 /dev/sda3，重新分割的 /dev/sda2，其開始及結束 sector 包含原來的 /dev/sda2 及 /dev/sda3，也就是將 /dev/sda2 及 /dev/sda3 合併為 /dev/sda2。

[root@localhost ~]# fdisk /dev/sda
Welcome to fdisk (util-linux 2.23.2).

Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Command (m for help): p

Disk /dev/sda: 19.8 GB, 19787972608 bytes, 38648384 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000a6d01

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048      821247      409600   83  Linux
/dev/sda2          821248    21792767    10485760   83  Linux
/dev/sda3        21792768    30181375     4194304   83  Linux
/dev/sda4        30181376    38647807     4233216    5  Extended
/dev/sda5        30183424    31207423      512000   82  Linux swap / Solaris
/dev/sda6        31209472    31229951       10240   83  Linux

Command (m for help): d
Partition number (1-6, default 6): 3    
Partition 3 is deleted

Command (m for help): d
Partition number (1,2,4-6, default 6): 2
Partition 2 is deleted

Command (m for help): n
Partition type:
   p   primary (1 primary, 1 extended, 2 free)
   l   logical (numbered from 5)
Select (default p): p
Partition number (2,3, default 2): 2
First sector (821248-38648383, default 821248): 
Using default value 821248
Last sector, +sectors or +size{K,M,G} (821248-30181375, default 30181375):         
Using default value 30181375
Partition 2 of type Linux and of size 14 GiB is set

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.

GUEST 重新開機。

[root@localhost ~]# reboot
Connection to 127.0.0.1 closed by remote host.
Connection to 127.0.0.1 closed.

重新登入 GUEST 後查看，LUKS 分割區已加大到 14G。

[root@dyw219 ~]# ssh -o VerifyHostKeyDNS=no -l kkdd -p 5679 127.0.0.1
Verification code: 
Password: 
Last login: Tue Mar 20 10:10:03 2018 from gateway
[kkdd@localhost ~]$ su -
Password: 
Last login: Tue Mar 20 10:10:13 CST 2018 on pts/0
[root@localhost ~]# lsblk 
NAME                                   MAJ:MIN RM  SIZE RO TYPE  MOUNTPOINT
sda                                      8:0    0 18.4G  0 disk  
├─sda1                                   8:1    0  400M  0 part  /boot
├─sda2                                   8:2    0   14G  0 part  
│ └─luks-b22f30aa-72d7-4523-aa21-dc516da53fc8
                                       253:0    0   14G  0 crypt /
├─sda4                                   8:4    0    1K  0 part  
├─sda5                                   8:5    0  500M  0 part  [SWAP]
└─sda6                                   8:6    0   10M  0 part  
sr0                                     11:0    1 55.3M  0 rom

但掛載在根目錄的分割區還是只有原來的 10G。

[root@localhost ~]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/dm-0        10G  7.2G  2.8G  73% /
devtmpfs        2.1G     0  2.1G   0% /dev
tmpfs           2.1G     0  2.1G   0% /dev/shm
tmpfs           2.1G  8.9M  2.1G   1% /run
tmpfs           2.1G     0  2.1G   0% /sys/fs/cgroup
/dev/sda1       397M  248M  150M  63% /boot
tmpfs           422M   12K  422M   1% /run/user/42
tmpfs           422M     0  422M   0% /run/user/1000
tmpfs           422M     0  422M   0% /run/user/0

必須先使用 cryptsetup resize luks 檔案系統。

[root@localhost ~]# cryptsetup -v resize luks-b22f30aa-72d7-4523-aa21-dc516da53fc8
Command successful.

再使用 resize2fs 重新調整 luks 檔案系統，出現以下錯誤，原因為檔案系統為 xfs 格式，不是 ext2/ext3/ext4 格式，不能使用 resize2fs 工具。

[root@localhost ~]# resize2fs /dev/mapper/luks-b22f30aa-72d7-4523-aa21-dc516da53fc8
resize2fs 1.42.9 (28-Dec-2013)
resize2fs: Bad magic number in super-block while trying to open /dev/mapper/luks-b22f30aa-72d7-4523-aa21-dc516da53fc8
Couldn't find valid filesystem superblock.

此 luks 分割區為 xfs 檔案系統，要使用 xfs_growfs 工具將檔案系統放大到 cryptsetup resize 調整的值。

[root@localhost ~]# xfs_growfs /dev/mapper/luks-b22f30aa-72d7-4523-aa21-dc516da53fc8 
meta-data=/dev/mapper/luks-b22f30aa-72d7-4523-aa21-dc516da53fc8 isize=512    agcount=4, agsize=655232 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0 spinodes=0
data     =                       bsize=4096   blocks=2620928, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal               bsize=4096   blocks=2560, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 2620928 to 3669504

再查看根目錄掛載點已放大到 14G。

[root@localhost ~]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/dm-0        14G  7.2G  6.8G  52% /
devtmpfs        2.1G     0  2.1G   0% /dev
tmpfs           2.1G     0  2.1G   0% /dev/shm
tmpfs           2.1G  8.9M  2.1G   1% /run
tmpfs           2.1G     0  2.1G   0% /sys/fs/cgroup
/dev/sda1       397M  248M  150M  63% /boot
tmpfs           422M   12K  422M   1% /run/user/42
tmpfs           422M     0  422M   0% /run/user/1000
tmpfs           422M     0  422M   0% /run/user/0

De-Yu Wang 2020-05-14