在CentOS6或RHEL6恢复上ext4文件系统误删除的文件详解程序员

首先说明:

[[email protected] ~]# rm -rf /      //这条命令不可以执行 
[[email protected] ~]# rm -rf /*    //这条命令可以执行,别去试

  ext4文件系统上误删除文件,可以用extundelete恢复。ext3恢复使用ext3grep。Windows恢复使用final data v2.0汉化版和easyrecovery等。

  误删除文件后,第一件事是避免误删除的文件内容被覆盖,这时可以卸载需要恢复文件的分区或以只读的方式挂载。

(1).下载extundelete

https://sourceforge.net/          开源软件发布中心

https://github.com/                   github项目托管平台

(2).准备实验环境

VMare12  CentOS6.8  添加一块硬盘20G

不会看这里,Linux空硬盘从分区到挂载

这里创建sdb1分区,挂载到/newpar下。

还有将CentOS6.8的光盘镜像挂载到/mnt下。

(3).复制一些测试文件,然后删除,以备测试恢复。

 这里为了更好的展示,安装一下tree。

[[email protected] ~]# rpm -ivh /mnt/Packages/tree-1.5.3-3.el6.x86_64.rpm 
warning: /mnt/Packages/tree-1.5.3-3.el6.x86_64.rpm: Header V3 RSA/SHA1 Signature, key ID c105b9de: NOKEY 
Preparing...                ########################################### [100%] 
   1:tree                   ########################################### [100%] 

下面开始复制文件

[[email protected] ~]# cp /etc/passwd /newpar/ 
[[email protected] ~]# cp /etc/hosts /newpar/ 
[[email protected] ~]# echo abc > a.txt 
[[email protected] ~]# mkdir -p /newpar/a/b/c/ 
[[email protected] ~]# cp a.txt  /newpar/a/ 
[[email protected] ~]# cp a.txt /newpar/a/b/ 
[[email protected] ~]# touch /newpar/a/b/test.txt 
[[email protected] ~]# tree /newpar/ 
/newpar/ 
├── a 
│   ├── a.txt 
│   └── b 
│       ├── a.txt 
│       ├── c    //空的 
│       └── test.txt    //空的 
├── hosts 
├── lost+found 
└── passwd 
4 directories, 5 files 

下面开始删除

[[email protected] ~]# rm -rf /newpar/{a,hosts,passwd} 
[[email protected] ~]# ls /newpar/ 
lost+found 

删完了,记得误删除第一步,卸载分区。如果是根目录看(7).扩展2

[[email protected] ~]# umount /newpar/    //不能在挂载点下卸载

使用df -a查看文件系统的挂载点

[[email protected] ~]# df -a 
Filesystem           1K-blocks    Used Available Use% Mounted on 
/dev/mapper/vg_centos6-lv_root 
                      17938864 3958368  13062584  24% / 
proc                         0       0         0    - /proc 
sysfs                        0       0         0    - /sys 
devpts                       0       0         0    - /dev/pts 
tmpfs                   953652      72    953580   1% /dev/shm 
/dev/sda1               487652   40913    421139   9% /boot 
/dev/sr0               3824484 3824484         0 100% /mnt 
none                         0       0         0    - /proc/sys/fs/binfmt_misc 
[[email protected] ~]# mkdir /cdrom 
[[email protected] ~]# mount /dev/sr0  /cdrom/ 
mount: block device /dev/sr0 is write-protected, mounting read-only 
[[email protected] ~]# df -a 
Filesystem           1K-blocks    Used Available Use% Mounted on 
/dev/mapper/vg_centos6-lv_root 
                      17938864 3958372  13062580  24% / 
proc                         0       0         0    - /proc 
sysfs                        0       0         0    - /sys 
devpts                       0       0         0    - /dev/pts 
tmpfs                   953652      72    953580   1% /dev/shm 
/dev/sda1               487652   40913    421139   9% /boot 
/dev/sr0               3824484 3824484         0 100% /mnt 
none                         0       0         0    - /proc/sys/fs/binfmt_misc 
/dev/sr0               3824484 3824484         0 100% /cdrom

(4).安装extundelete

 将下载好的extundelete上传到服务器中。

[[email protected] ~]# ls 
anaconda-ks.cfg            install.log         模板  文档  桌面 
a.txt                      install.log.syslog  视频  下载 
extundelete-0.2.4.tar.bz2  公共的              图片  音乐 

解压

[[email protected] ~]# tar -jxvf extundelete-0.2.4.tar.bz2    //-j过滤bz2格式 

准备依赖包(我的CentOS6.8镜像好像不全,其实还可以用rpm -ivh安装gcc-c++和e2fsprogs-devel)

[[email protected] extundelete-0.2.4]# yum -y install gcc-c++ 
[[email protected] extundelete-0.2.4]# yum -y install e2fsprogs-devel

安装extundelete

[[email protected] ~]# cd extundelete-0.2.4 
[[email protected] extundelete-0.2.4]# ./configure    //检查系统安装环境,为了生成Makefile文件 
Configuring extundelete 0.2.4 
Writing generated files to disk 
[[email protected] extundelete-0.2.4]# make -j 4    //编译,把源代码编译成可执行的二进制文件。-j 4使用4进程或4核同时编译,提高编译速度。根据实际配置修改 
make -s all-recursive 
Making all in src 
extundelete.cc:571: 警告:未使用的参数‘flags’ 
[[email protected] extundelete-0.2.4]# make install    //安装 
Making install in src 
  /usr/bin/install -c extundelete '/usr/local/bin'    //在此目录下 

(5).恢复文件

创建一个文件夹,将恢复的文件保存到文件夹内

[[email protected] ~]# umount /dev/sdb1    //确保卸载分区 
umount: /dev/sdb1: not mounted 
[[email protected] ~]# mkdir test    //创建test文件夹 
[[email protected] ~]# cd test/ 
[[email protected] test]# ls

查看inode号

[[email protected] test]# extundelete /dev/sdb1 --inode 2    //ext4文件系统分区根目录的inode值为2,xfs文件系统分区根目录的inode值为64。 
NOTICE: Extended attributes are not restored. 
Loading filesystem metadata ... 160 groups loaded. 
Group: 0 
Contents of inode 2: 
0000 | ed 41 00 00 00 10 00 00 60 7b 2e 5c 4e 7b 2e 5c | .A......`{./N{./ 
0010 | 4e 7b 2e 5c 00 00 00 00 00 00 03 00 08 00 00 00 | N{./............ 
0020 | 00 00 00 00 06 00 00 00 21 24 00 00 00 00 00 00 | ........!$...... 
0030 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................ 
0040 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................ 
0050 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................ 
0060 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................ 
0070 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................ 
0080 | 1c 00 00 00 a8 37 a3 c1 a8 37 a3 c1 7c d2 20 60 | .....7...7..|. ` 
0090 | 7a 72 2e 5c 00 00 00 00 00 00 00 00 00 00 00 00 | zr./............ 
00a0 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................ 
00b0 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................ 
00c0 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................ 
00d0 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................ 
00e0 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................ 
00f0 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................ 
 
Inode is Allocated 
File mode: 16877 
Low 16 bits of Owner Uid: 0 
Size in bytes: 4096 
Access time: 1546550112 
Creation time: 1546550094 
Modification time: 1546550094 
Deletion Time: 0 
Low 16 bits of Group Id: 0 
Links count: 3 
Blocks count: 8 
File flags: 0 
File version (for NFS): 0 
File ACL: 0 
Directory ACL: 0 
Fragment address: 0 
Direct blocks: 9249, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 
Indirect block: 0 
Double indirect block: 0 
Triple indirect block: 0 
 
File name                                       | Inode number | Deleted status 
.                                                 2 
..                                                2 
lost+found                                        11 
passwd                                            12             Deleted 
hosts                                             13             Deleted 
a                                                 262145         Deleted 

1)通过inode恢复

根据上面的inode值,使用–restore-inode选项恢复passwd

[[email protected] test]# extundelete /dev/sdb1 --restore-inode 12 
NOTICE: Extended attributes are not restored. 
Loading filesystem metadata ... 160 groups loaded. 
Loading journal descriptors ... 67 descriptors loaded. 
[[email protected] test]# ls -l 
总用量 4 
drwxr-xr-x. 2 root root 4096 1月   4 07:07 RECOVERED_FILES    //可以看到一个新的文件夹 
[[email protected] test]# cd RECOVERED_FILES/ 
[[email protected] RECOVERED_FILES]# ls 
file.12    //这就是恢复出来的文件 
[[email protected] RECOVERED_FILES]# diff /etc/passwd file.12  //比较一下是否有不同。没有输出就是一样。

2)通过文件名恢复

也可以根据上面的文件名,使用–restore-file选项恢复passwd。这样还可以同时还原文件名

[[email protected] test]# extundelete /dev/sdb1 --restore-file passwd 
NOTICE: Extended attributes are not restored. 
Loading filesystem metadata ... 160 groups loaded. 
Loading journal descriptors ... 67 descriptors loaded. 
Successfully restored file passwd 
[[email protected] test]# ls RECOVERED_FILES/ 
file.12  passwd    //可以看到恢复出了一个名为passwd的文件 
[[email protected] test]# diff RECOVERED_FILES/file.12 RECOVERED_FILES/passwd    //两个文件内容是一样的

3)恢复某个目录

使用–restore-directory选项恢复文件夹a。注意:空目录和空文件无法恢复

[[email protected] test]# extundelete /dev/sdb1 --restore-directory a 
NOTICE: Extended attributes are not restored. 
Loading filesystem metadata ... 160 groups loaded. 
Loading journal descriptors ... 67 descriptors loaded. 
Searching for recoverable inodes in directory a ... 
7 recoverable inodes found. 
Looking through the directory structure for deleted files ... 
3 recoverable inodes still lost.    //3个可回收的inode仍然丢失 
[[email protected] test]# tree RECOVERED_FILES/a/ 
RECOVERED_FILES/a/ 
├── a.txt 
└── b 
    └── a.txt    //少了空文件夹c和空文件test.txt 
 
1 directory, 2 files

4)恢复所有文件

 使用–restore-all选项恢复所有文件。注意:空目录和空文件无法恢复

[[email protected] test]# rm -rf * 
[[email protected] test]# ls 
[[email protected] test]# extundelete /dev/sdb1 --restore-all 
NOTICE: Extended attributes are not restored. 
Loading filesystem metadata ... 160 groups loaded. 
Loading journal descriptors ... 67 descriptors loaded. 
Searching for recoverable inodes in directory / ... 
7 recoverable inodes found. 
Looking through the directory structure for deleted files ... 
0 recoverable inodes still lost. 
[[email protected] test]# tree RECOVERED_FILES/ 
RECOVERED_FILES/ 
├── a 
│   ├── a.txt 
│   └── b 
│       └── a.txt    //少了空目录c和空文件test.txt 
├── hosts 
└── passwd 
 
2 directories, 4 files

(6).扩展1:

Linux文件系统由三部分组成:文件名,inode(存放文件元数据信息),block(真正存放数据)。Windows也由这三部分组成。

1)查看inode号

[[email protected] ~]# ls -i anaconda-ks.cfg 
137428 anaconda-ks.cfg

查看inode中的文件属性。通过stat命令查看inode中包含的内容

[[email protected] ~]# stat anaconda-ks.cfg 
  File: "anaconda-ks.cfg" 
  Size: 1700            Blocks: 8          IO Block: 4096   普通文件 
Device: fd00h/64768d    Inode: 137428      Links: 1 
Access: (0600/-rw-------)  Uid: (    0/    root)   Gid: (    0/    root) 
Access: 2018-09-01 18:01:33.658648102 +0800 
Modify: 2018-03-13 18:29:40.674999889 +0800 
Change: 2018-03-13 18:29:48.813999887 +0800

2)Block块:真正存储数据的地方

为什么删除比复制块?因为一般的删除都是逻辑删除,只删除了文件名。当有新的文件占用inode和block,此时只有找专业的数据恢复公司,通过奇偶校验找回文件。

(7).扩展2:

如果想恢复根下删除的文件怎么办?

方法一:立即断电(因为正常关机会产生日志,防止日志对数据覆盖),然后把磁盘以只读方式挂在到另一台相同相同的电脑中进行恢复

方法二:把extundelete在另一台相同相同的电脑上安装好,然后复制到U盘中。把U盘插入服务器,恢复时将恢复的文件保存到U盘中(不要让恢复的数据写到根下,那样会覆盖之前删除的文件)

原创文章,作者:ItWorker,如若转载,请注明出处:https://blog.ytso.com/2810.html

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