如何在不弹出CDROM的情况下更新Linux中的CDROM大小？

Question

怎样才能让Linux在不弹出CDROM的情况下更新它对CDROM大小的概念？换句话说，我怎么才能在不弹出的情况下挂载刚刚烧录的CDROM呢？

我在CDROM上做无人值守的增量备份。my script每天都会使用"wodim -msinfo“和"genisoimage -C”来生成一个图像，然后使用"wodim -multi“将其附加到CDROM上。然后，我的脚本挂载CDROM，以检查新文件是否被正确附加。只有在挂载之前更新了Linux关于CDROM大小的概念后，该脚本才能读取新文件。大小在/sys/block/sr2/size和/proc/partitions中。以前我的脚本使用"eject“，然后使用"eject -t”让Linux重新读取CDROM。"eject -t“在我的新CDROM刻录机上不起作用。如何在不弹出CDROM的情况下更新/proc/分区？

似乎"wodim -msinfo“和"genisoimage -C”步骤还要求CDROM在上次刻录到CDROM后已经弹出，否则我会收到消息"genisoimage: Invalid argument.Seek error on old image“。

2003年有人问过这个问题，但他们得到的答案并没有为我更新CDROM的大小。http://compgroups.net/comp.os.linux.questions/rescan-cdrom-frm-command-line/456190

#include <fcntl.h>
#include <stdio.h>
#include <linux/cdrom.h>
int main(void)
{
    int i = 0;
    int fd = open("/dev/cdrom", O_RDWR);
    if (fd == -1)
    {
            perror("Could not open cdrom");
            return 1;
    }
    if (ioctl(fd, CDROM_MEDIA_CHANGED)) perror("ioctl");
    if (ioctl(fd, CDROMRESET)) perror("ioctl CDROMRESET");
    if (ioctl(fd, CDROM_NEXT_WRITABLE, &i))
            perror("ioctl CDROM_NEXT_WRITABLE,");
    else
            printf("CDROM_NEXT_WRITABLE %d\n", i);
    if (ioctl(fd, CDROM_LAST_WRITTEN, &i))
            perror("ioctl CDROM_LAST_WRITTEN,");
    else
            printf("CDROM_LAST_WRITTEN %d\n", i);
    return 0;
}

这正是我创建新CDROM时发生的事情。我必须弹出它，然后把它推回去，才能让它上马。

% genisoimage -r -V archive -input-charset ASCII -quiet /usr/lib/vlc > /tmp/libvlc.iso
% grep -H sr2 /proc/partitions ; cat /sys/block/sr2/size
/proc/partitions:  11        2          2 sr2
4
% wodim driveropts=burnfree -tao -data  dev=/dev/sr2 /tmp/libvlc.iso
wodim: Operation not permitted. Warning: Cannot raise RLIMIT_MEMLOCK limits.
Device type    : Removable CD-ROM
Version        : 0
Response Format: 2
Capabilities   : 
Vendor_info    : 'TSSTcorp'
Identification : 'CDDVDW SE-S084C '
Revision       : 'TU00'
Device seems to be: Generic mmc2 DVD-R/DVD-RW.
Using generic SCSI-3/mmc   CD-R/CD-RW driver (mmc_cdr).
Driver flags   : MMC-3 SWABAUDIO BURNFREE 
Supported modes: TAO PACKET SAO SAO/R96P SAO/R96R RAW/R16 RAW/R96P RAW/R96R
Speed set to 1764 KB/s
Starting to write CD/DVD at speed  10.0 in real TAO mode for single session.
Last chance to quit, starting real write in    0 seconds. Operation starts.
Track 01: Total bytes read/written: 17078272/17078272 (8339 sectors).
% grep -H sr2 /proc/partitions ; cat /sys/block/sr2/size
/proc/partitions:  11        2          2 sr2
4
% sudo mount /dev/sr2 /mnt
mount: /dev/sr2 is write-protected, mounting read-only
mount: wrong fs type, bad option, bad superblock on /dev/sr2,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.
% grep -H sr2 /proc/partitions ; cat /sys/block/sr2/size
/proc/partitions:  11        2          2 sr2
4
% sudo mount /dev/sr2 /mnt
mount: /dev/sr2 is write-protected, mounting read-only
mount: wrong fs type, bad option, bad superblock on /dev/sr2,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.
% sudo eject /dev/sr2
% #push CDRW back in
% grep -H sr2 /proc/partitions ; cat /sys/block/sr2/size
/proc/partitions:  11        2      16682 sr2
33364
% sudo mount /dev/sr2 /mnt
mount: /dev/sr2 is write-protected, mounting read-only

我尝试过各种hdparm选项，但它们都不起作用，也不会改变内核对CDROM大小的看法，也不会允许挂载它。

:; sudo hdparm -z  /dev/sr2 

/dev/sr2:
 re-reading partition table
 BLKRRPART failed: Invalid argument
:; sudo hdparm -F  /dev/sr2 

/dev/sr2:
SG_IO: bad/missing sense data, sb[]:  70 00 05 00 00 00 00 0a 00 00 00 00 20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
SG_IO: bad/missing sense data, sb[]:  70 00 05 00 00 00 00 0a 00 00 00 00 20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
:; sudo hdparm -Y  /dev/sr2 

/dev/sr2:
 issuing sleep command
SG_IO: bad/missing sense data, sb[]:  70 00 05 00 00 00 00 0a 00 00 00 00 20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
:; sudo hdparm -w  /dev/sr2 

/dev/sr2:
 resetting drive
 HDIO_DRIVE_RESET failed: Invalid argument
:; grep -H sr2 /proc/partitions ; cat /sys/block/sr2/size
/proc/partitions:  11        2          2 sr2
4
:; sudo mount /dev/sr2 /mnt
mount: /dev/sr2 is write-protected, mounting read-only
mount: wrong fs type, bad option, bad superblock on /dev/sr2,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.

指定文件系统的类型无济于事。

:; grep -H sr2 /proc/partitions ; cat /sys/block/sr2/size
/proc/partitions:  11        2          2 sr2
4
:; sudo mount -t iso9660 /dev/sr2 /mnt
[sudo] password for root: 
(pam_mount.c:365): pam_mount 2.14: entering auth stage
mount: /dev/sr2 is write-protected, mounting read-only
mount: wrong fs type, bad option, bad superblock on /dev/sr2,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.
(pam_mount.c:133): clean system authtok=0x7f0a33b97450 (1073741824)
:; grep -H sr2 /proc/partitions ; cat /sys/block/sr2/size
/proc/partitions:  11        2          2 sr2
4

我从dmesg(1)得到的消息是

[1209552.092616] isofs_fill_super: bread failed, dev=sr2, iso_blknum=16, block=16

Answer 1

我的BD驱动器也有同样的问题。对我来说起作用的是解除设备的绑定，然后再重新绑定。下面是粗略的步骤

• 通过"lsscsi -v“查找usb设备

11:0:0:0 cd/dvd总线BDDVDW SE-506AB /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0/host11/target11:0:0/11:0:0:0

• power /dev/sr1目录:/sys/ TSSTcorp /scsi/ TS01 /11:0:0:0:0关闭设备/准备断开连接

sudo bash /sys/bus/usb/drivers/usb/unbind"

• power "echo 2-1.2 | tee -c up the device /再次连接

sudo bash /sys/bus/usb/drivers/usb/bind" "echo 2-1.2 | tee -c

解除绑定/绑定是重置许多usb设备的好方法...

Answer 2

基于GMA的回答，我能够组合出一些我认为更通用的东西：

• 通过"lsscsi -v"
• cd找到要解除绑定的scsi id，然后绑定。
  • echo "1:0:0:0“>解除绑定
  • echo "1:0:0:0”> bind

​

Answer 3

也许可以使用blockdev(8)命令？

*blockdev dev --flushbufs --rereadpt /dev/sr0