如何在不弹出CD的情况下让Linux更新其对CDROM大小的想法？换句话说，如何在不先弹出CDROM的情况下安装新烧录的CDROM？
我正在无人值守的增量备份到CDROM上。每天my script使用“wodim -msinfo”和“genisoimage -C”来生成使用“wodim -multi”附加到CDROM的图像。然后我的脚本安装CDROM以检查是否正确附加了新文件。如果Linux在安装之前更新了CDROM大小的想法，则脚本只能读取新文件。大小在/ sys / block / sr2 / size和/ proc / partitions中。以前我的脚本使用“eject”然后“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自上次刻录后已经弹出到CDROM，否则我收到消息“genisoimage：无效的参数。查找旧图像上的错误”
有人在2003年提出了这个问题，但他们收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时发生的情况。我必须弹出它，然后将其推回以使其安装。
% 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
我尝试了各种hdparm选项，但它们都没有用，也没有改变内核对CDROM大小的想法或允许它安装。
:; 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没有帮助。
:; 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
答案 0 :(得分：1)
我对BD驱动器有同样的问题。对我有用的是取消绑定（取消）设备并再次重新绑定它。这里是粗略的步骤
通过＆＃34; lsscsi -v＆＃34;
找到USB设备[11:0:0:0] cd/dvd TSSTcorp BDDVDW SE-506AB TS01 /dev/sr1
dir: /sys/bus/scsi/devices/11:0:0:0 [/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]
关闭设备电源/准备断开连接
sudo bash -c "echo 2-1.2 | tee /sys/bus/usb/drivers/usb/unbind"
启动设备/再次连接
sudo bash -c "echo 2-1.2 | tee /sys/bus/usb/drivers/usb/bind"
Unbind / bind是重置许多USB设备的好方法......
答案 1 :(得分：0)
也许使用blockdev（8）命令？
答案 2 :(得分：0)
根据GMA的回答，我能够整理出一些我认为更通用的内容：