device-driver - Lostup -d 不工作

Question

我在/tmp 文件夹中设置了 5 个带有备份文件的循环设备作为原始 40 MB 文件。

$ losetup -l
NAME       SIZELIMIT OFFSET AUTOCLEAR RO BACK-FILE
/dev/loop1         0      0         1  0 /tmp/1
/dev/loop2         0      0         0  0 /tmp/2
/dev/loop3         0      0         0  0 /tmp/3
/dev/loop4         0      0         0  0 /tmp/4
/dev/loop5         0      0         0  0 /tmp/5

我使用lvm为前4个设备创建了一个RAID阵列。因此，前 4 个设备变得繁忙，如下所示:

$ lsblk 
NAME                    MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda                       8:0    0 931.5G  0 disk 
├─sda1                    8:1    0   100M  0 part /boot/efi
├─sda2                    8:2    0   900M  0 part 
├─sda3                    8:3    0   128M  0 part 
├─sda4                    8:4    0 372.6G  0 part 
├─sda5                    8:5    0 140.5G  0 part /
├─sda6                    8:6    0    15G  0 part 
├─sda7                    8:7    0 186.3G  0 part 
├─sda8                    8:8    0  37.3G  0 part [SWAP]
├─sda9                    8:9    0  93.1G  0 part 
└─sda10                   8:10   0  40.8G  0 part 
loop1                     7:1    0  78.1M  0 loop 
├─vol_vg-raid4_rmeta_0  252:0    0     4M  0 lvm  
│ └─vol_vg-raid4        252:8    0    48M  0 lvm  
└─vol_vg-raid4_rimage_0 252:1    0    16M  0 lvm  
  └─vol_vg-raid4        252:8    0    48M  0 lvm  
loop2                     7:2    0  78.1M  0 loop 
├─vol_vg-raid4_rmeta_1  252:2    0     4M  0 lvm  
│ └─vol_vg-raid4        252:8    0    48M  0 lvm  
└─vol_vg-raid4_rimage_1 252:3    0    16M  0 lvm  
  └─vol_vg-raid4        252:8    0    48M  0 lvm  
loop3                     7:3    0  78.1M  0 loop 
├─vol_vg-raid4_rmeta_2  252:4    0     4M  0 lvm  
│ └─vol_vg-raid4        252:8    0    48M  0 lvm  
└─vol_vg-raid4_rimage_2 252:5    0    16M  0 lvm  
  └─vol_vg-raid4        252:8    0    48M  0 lvm  
loop4                     7:4    0  78.1M  0 loop 
├─vol_vg-raid4_rmeta_3  252:6    0     4M  0 lvm  
│ └─vol_vg-raid4        252:8    0    48M  0 lvm  
└─vol_vg-raid4_rimage_3 252:7    0    16M  0 lvm  
  └─vol_vg-raid4        252:8    0    48M  0 lvm  

我现在尝试删除循环设备 1。我在控制台或 dmseg 中都没有收到任何警告/错误:

$ sudo losetup -d /dev/loop1 
shehbaz@donjaffer:~$ 

现在，我再次列出所有设备如下:

$ losetup -l
NAME       SIZELIMIT OFFSET AUTOCLEAR RO BACK-FILE
/dev/loop1         0      0         1  0 /tmp/1
/dev/loop2         0      0         0  0 /tmp/2
/dev/loop3         0      0         0  0 /tmp/3
/dev/loop4         0      0         0  0 /tmp/4
/dev/loop5         0      0         0  0 /tmp/5
shehbaz@donjaffer:~$

我还看到 lsblk 输出与我上面提供的相同。

我尝试在我之前尝试过的命令上运行 strace(以查看是否存在某些权限被拒绝或未报告的某些其他形式的错误)，我得到以下输出:

$ sudo strace losetup -d /dev/loop1
execve("/sbin/losetup", ["losetup", "-d", "/dev/loop1"], [/* 17 vars */]) = 0
brk(0)                                  = 0x1985000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fc13f271000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=108331, ...}) = 0
mmap(NULL, 108331, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fc13f256000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libsmartcols.so.1", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260R\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0644, st_size=134536, ...}) = 0
mmap(NULL, 2233952, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fc13ee2e000
mprotect(0x7fc13ee4e000, 2093056, PROT_NONE) = 0
mmap(0x7fc13f04d000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1f000) = 0x7fc13f04d000
mmap(0x7fc13f04f000, 1632, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fc13f04f000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0`\v\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1869392, ...}) = 0
mmap(NULL, 3972864, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fc13ea64000
mprotect(0x7fc13ec24000, 2097152, PROT_NONE) = 0
mmap(0x7fc13ee24000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1c0000) = 0x7fc13ee24000
mmap(0x7fc13ee2a000, 16128, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fc13ee2a000
close(3)                                = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fc13f255000
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fc13f253000
arch_prctl(ARCH_SET_FS, 0x7fc13f253740) = 0
mprotect(0x7fc13ee24000, 16384, PROT_READ) = 0
mprotect(0x7fc13f04d000, 4096, PROT_READ) = 0
mprotect(0x60f000, 4096, PROT_READ)     = 0
mprotect(0x7fc13f273000, 4096, PROT_READ) = 0
munmap(0x7fc13f256000, 108331)          = 0
brk(0)                                  = 0x1985000
brk(0x19a6000)                          = 0x19a6000
open("/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=7216688, ...}) = 0
mmap(NULL, 7216688, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fc13e382000
close(3)                                = 0
stat("/sys/block", {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
uname({sys="Linux", node="donjaffer", ...}) = 0
stat("/dev/loop-control", {st_mode=S_IFCHR|0660, st_rdev=makedev(10, 237), ...}) = 0
stat("/dev/loop1", {st_mode=S_IFBLK|0660, st_rdev=makedev(7, 1), ...}) = 0
open("/dev/loop1", O_RDONLY|O_CLOEXEC)  = 3
ioctl(3, LOOP_CLR_FD)                   = 0
close(3)                                = 0
close(1)                                = 0
close(2)                                = 0
exit_group(0)                           = ?
+++ exited with 0 +++
shehbaz@donjaffer:~$ 

我仍然看到所有设备都在使用 Lostup 命令。 -d 选项是否工作不正常？我也尝试卸载/dev/loop1，但它告诉我/dev/loop1 未安装。

$ umount -l /dev/loop1
umount: /dev/loop1: not mounted
shehbaz@donjaffer:~$

请帮忙。谢谢你。

Answer 1

关于上述 Tom hale 代码片段的重要说明:

bash 脚本中使用的lostup 命令对IFS 的值敏感。

试试这个来亲眼看看:

line="/dev/loop8 /somefile"
losetup $line     # this works
IFS=""
losetup $line     # this one will fail

如果您的变量 ($line) 包含多个参数，则 IFS 值允许 Lostup 检测它们。通过清除它，最后一个lostup认为完整的变量只有1个参数，这显然失败了。