linuxroot命令大全：linux mount命令学习

linuxroot命令大全：linux mount命令学习7. umount这个文件系统，可以看到原先的文件系统/tmp_fs又恢复出来了，sh-# umount /mnt/usb/sda1/sh-# ls /tmp_fstest.txtsh-# mountrootfs on / type rootfs (rw)/dev/root on / type squashfs (ro relatime)none on /proc type proc (rw relatime)none on /sys type sysfs (rw relatime)none on /tmp type tmpfs (rw relatime)none on /opt type tmpfs (rw relatime)none on /tmp_fs type tmpfs (rw relatime)none on /proc/bus/usb type usbfs (rw relat

1. 先查看下mount U盘之前系统上已经挂载了哪些文件系统，
sh-# cat /proc/mounts
rootfs / rootfs rw 0 0
/dev/root / squashfs ro relatime 0 0
none /proc proc rw relatime 0 0
none /sys sysfs rw relatime 0 0
none /tmp tmpfs rw relatime 0 0
none /opt tmpfs rw relatime 0 0
none /tmp_fs tmpfs rw relatime 0 0
none /proc/bus/usb usbfs rw relatime 0 0

2. 接下来我们要知道挂载的U盘名是什么，这只U盘是什么类型的文件系统，
sh-# fdisk -l

Disk /dev/sda: 4002 MB 4002910208 bytes
32 heads 63 sectors/track 3878 cylinders
Units = cylinders of 2016 * 512 = 1032192 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 1 3878 3908992 b Win95 FAT32

3. 查看当前系统中支持哪些类型的文件系统，
sh-# cat /proc/filesystems
nodev sysfs
nodev rootfs
nodev bdev
nodev proc
nodev tmpfs
nodev debugfs
nodev sockfs
nodev usbfs
nodev pipefs
nodev anon_inodefs
nodev devpts
ext2
nodev ramfs
vfat
nodev mqueue
nodev mtd_inodefs
NTFS

4. 挂载一个文件系统必须有一个mount point，所以这里暂时将这只U盘挂载到/tmp_fs这个目录下。
sh-# touch /tmp_fs/test.txt
sh-# ls -l /tmp_fs/test.txt
-rw-r--r-- 1 root root 0 Jan 1 00:07 /tmp_fs/test.txt

5. 真正要mount这个U盘了，
sh-# mount -t vfat /dev/sda1 /tmp_fs

6. 检查是否有挂载成功，
sh-# cat /proc/mounts
rootfs / rootfs rw 0 0
/dev/root / squashfs ro relatime 0 0
none /proc proc rw relatime 0 0
none /sys sysfs rw relatime 0 0
none /tmp tmpfs rw relatime 0 0
none /opt tmpfs rw relatime 0 0
none /tmp_fs tmpfs rw relatime 0 0
none /proc/bus/usb usbfs rw relatime 0 0
/dev/sda1 /tmp_fs vfat rw relatime fmask=0022 dmask=0022 codepage=cp437 iocharset=iso8859-1 shortname=mixed errors=remount-ro 0 0
接下来我们再访问看看啦，
sh-# ls /tmp_fs/
TF1014VIZUSMTKO0-420.VOB gdb
tcpdump lsof
真的可以访问U盘里面的文件耶，说明mount成功了。

7. umount这个文件系统，可以看到原先的文件系统/tmp_fs又恢复出来了，
sh-# umount /mnt/usb/sda1/
sh-# ls /tmp_fs
test.txt
sh-# mount
rootfs on / type rootfs (rw)
/dev/root on / type squashfs (ro relatime)
none on /proc type proc (rw relatime)
none on /sys type sysfs (rw relatime)
none on /tmp type tmpfs (rw relatime)
none on /opt type tmpfs (rw relatime)
none on /tmp_fs type tmpfs (rw relatime)
none on /proc/bus/usb type usbfs (rw relatime)

以上说明的是如何mount一个FAT32类型文件系统的U盘。
接下来，我们要将U盘format成NTFS类型的文件系统，再试试看能不能正常挂载。
mount失败了，要如何才能mount成功呢？
sh-# busybox fdisk -l

Disk /dev/sda: 4002 MB 4002910208 bytes
32 heads 63 sectors/track 3878 cylinders
Units = cylinders of 2016 * 512 = 1032192 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 1 3878 3908992 7 HPFS/NTFS

sh-# mount -t ntfs /dev/sda1 /tmp_fs/
mount: wrong fs type bad option bad superblock on /dev/sda1
missing codepage or helper program or other error
In some cases useful info is found in syslog - try
dmesg | tail or so

有时候需要将文件系统从ro改成rw或者从rw更改成ro，我们以U盘进行实验。

1. 通过mount命令查看/dev/sda1为rw的文件系统，
sh-# mount
rootfs on / type rootfs (rw)
/dev/root on / type squashfs (ro relatime)
none on /proc type proc (rw relatime)
none on /sys type sysfs (rw relatime)
none on /tmp type tmpfs (rw relatime)
none on /opt type tmpfs (rw relatime)
none on /var/run type tmpfs (rw relatime)
none on /proc/bus/usb type usbfs (rw relatime)
/dev/sda1 on /tmp/mnt/usb/sda1 type vfat (rw noatime fmask=0000 dmask=0000 allow_utime=0022 codepage=cp437 iocharset=utf8 shortname=mixed errors=continue)

2. 测试下是否可以写入/dev/sda1，
sh-# touch /tmp/mnt/usb/sda1/test.txt
sh-# ls -l /tmp/mnt/usb/sda1/test.txt
-rwxrwxrwx 1 root root 0 Jan 1 00:13 /tmp/mnt/usb/sda1/test.txt

3. 将/dev/sda1这个device重新挂载成ro的文件系统，
sh-# mount -o remount ro /tmp/mnt/usb/sda1/

4. 再次使用mount命令进行查看，你会发现/dev/sda1已经变成ro了。
sh-# mount
rootfs on / type rootfs (rw)
/dev/root on / type squashfs (ro relatime)
none on /proc type proc (rw relatime)
none on /sys type sysfs (rw relatime)
none on /tmp type tmpfs (rw relatime)
none on /opt type tmpfs (rw relatime)
none on /var/run type tmpfs (rw relatime)
none on /proc/bus/usb type usbfs (rw relatime)
/dev/sda1 on /tmp/mnt/usb/sda1 type vfat (ro noatime fmask=0000 dmask=0000 allow_utime=0022 codepage=cp437 iocharset=utf8 shortname=mixed errors=continue)

5. 通过实验来验证一下是不是真的有效，
sh-# touch /tmp/mnt/usb/sda1/test.txt
touch: cannot touch `/tmp/mnt/usb/sda1/test.txt': Read-only file system

当然如果你的文件系统在忙比如有打开着的文件，那么remount就会失败。
sh-# mount -o remount ro /tmp/
mount: /tmp is busy
sh-# echo $?
32

sh-# umount /tmp/
umount: /tmp: device is busy.
(In some cases useful info about processes that use
the device is found by lsof(8) or fuser(1))

如果设备处于busy状态，而你却执意要umount这个设备。
可以使用lsof定位哪些进程打开了文件，然后再将这个进程杀死，
再去umount应该就能成功卸载这个设备了。

待确认问题：
linux mount ntfs文件系统？