我正在无障碍的增量备份到CDROM.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来检查新文件是否正确附加.如果Linux在安装之前更新了CDROM大小的思想,则该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“弹出”,然后“弹出-t”让Linux重新读取CDROM. “弹出-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 / partition更新？

看来,“wodim -msinfo”和“genisoimage -C”步骤也要求CDROM自从上次刻录到CDROM之后被弹出,否则我得到消息“genisoimage：无效的参数,在旧的图像上寻找错误”.

有人在2003年问这个问题,但他们收到的答案并不会更新我的CDROM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;
}

这正是当我创建新的CDROM时会发生什么.我必须弹出它,然后将其推回来安装.

% 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,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

我已经尝试过各种各样的hdparm选项,但是它们都没有工作,也没有改变内核对CDROM大小的想法,或允许它挂载.

:; sudo hdparm -z  /dev/sr2 

/dev/sr2:
 re-reading partition table
 BLKRRPART @R_404_159@: 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 @R_404_159@: 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,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,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

从dmesg(1)得到的消息是

[1209552.092616] isofs_fill_super: bread @R_404_159@,dev=sr2,iso_blknum=16,block=16