Messages in this thread |  | | | Date | Fri, 30 Mar 2007 13:17:44 +0200 | | From | Eduard Bloch <> | | Subject | broken device locking, sg vs. sg_io on block devices |
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Hello,
I am talking this issue to LKML now.
Short story: using O_EXCL on /dev/srX alone does not help to prevent other process from killing your burn process by just reading the /dev/sgX device associated with yours, and vice versa. We have done the best we could to make safe operation (in contrary to Schilling's kill-this-evil-hald-thing bitching) but that is not enough, the locking has to be established on kernel layer.
Long story: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=413960 https://bugzilla.novell.com/show_bug.cgi?id=226019 http://lists.alioth.debian.org/pipermail/debburn-devel/2007-February/000297.html and other error messages.
There is AFAICS no simple way to establish locking across the driver borders. If kernel developers have a good idea, any help is appreciated.
Below are the typical symptoms: wodim operates via /dev/sgX because the user chosen it this way, some other process (most likely hald) comes along and reads from /dev/sr0 and the drive gets confused. Boom.
Regards, Eduard.
* Gerald Lutter [Mon, Mar 26 2007, 06:10:44PM]: > Hello List, > > i've tried to burn the grml_0.9.iso to a cdr/cd-rw medium using wodim from > cdrkit 1.1.2 and the burner HL-DT-ST GMA-4082N. The iso can be fetched > >from "http://www.grml.org". > > To make a long story short, burning this image to dvd+r and dvd+rw media works > without any problems but I need this image on a cdr or cd-rw medium. I've > attatched the output of the command I used to this mail: > > /usr/bin/wodim -vvv -VVV gracetime=2 dev=2,0,0 speed=10 ^^^^^^^^^ > driveropts=burnfree -eject -overburn -data /tmp/grml_0.9.iso ... > Track 01: 0 of 692 MB written. > write track data: error after 317440 bytes ... > Sense Key: 0x2 Not Ready, Segment 0 > Sense Code: 0x04 Qual 0x08 (logical unit not ready, long write in progress) Fru 0x0 > Sense flags: Blk 0 (not valid)
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