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Re: libgparted bug.




On Friday 09 February 2018 05:17:35 Thomas Schmitt wrote:

> Hi,
>
> > Got the sonofabitch, I added sdd to the ignore line
> > in /lib/udev/rules.d/60-persistent-storage.rules.
>
> What exactly did you do ?
> ("ignore line" does not give me insight when looking at the file.)
>
> > I wonder if I could make udev
> > aware that gparted was running.  That would be ideal.
>
> Ideal would be if the systemd/udev community would take into respect
> that they are not the only ones who want to access devices.
>
> If i execute
>   dd if=/dev/sr4 count=1 of=/dev/null
> while the DVD drive tray is out, then the tray gets pulled in,
> followed by the immediate error message "No medium found", and then
> the tray comes out immediately.
> On a second try, the tray stays in. But again dd reports "No medium
> found" and fails.
>
> I can see the theoretically sufficient waiting loop in function
> sr_do_ioctl() of drivers/scsi/sr_ioctl.c . It should really suffice,
> because i have a similar repetition loop in libburn, and i can see by
> libburn's SCSI log that the drive only emits the expected reply
> messages which should cause the sr_do_ioctl() loop to repeat the SCSI
> command in question.
>
> Everything in the kernel looks like it should work. Nevertheless, some
> entity must be accessing the drive without going through sr_do_ioctl()
> and obviously it has no clue of the peculiarities of a DVD drive.
>
> This looks much like the footprints of systemd and udev.
> I fiddled with 60-persistent-storage.rules too, but could not cause a
> change in behavior.
> Thus my request to see your succeful remedy for sdd.

# skip rules for inappropriate block devices
KERNEL=="fd*|mtd*|nbd*|gnbd*|btibm*|dm-*|md*|sdd", 
GOTO="persistent_storage_end"

The
|sdd
is the addition.

Now to calculate how much of sdd to have dd make a copy of. IOf I use a 
bs=65536, then count=122,070 covers 8Gb, and it says 7.74 now belongs 
toi part 7. The first 6 parts only occupy about 140 megs.
lets see if this gets me a working image once dd'd back to any card 16Gb 
or bigger.

dd if=/dev/sdd of=rock-img-shrunk.img bs=65536 count=122070
Based on my pisspoor short term memory, I wrote me a script to make 
endless copies :-) Now lets see if that works. Seems to be, led in 
reader is blinking.
122070+0 records in
122070+0 records out
7999979520 bytes (8.0 GB) copied, 399.487 s, 20.0 MB/s

But gparted can't see a thing except an empty card. WTF? Looking thru the 
disk file the above dd invocation generated. Slow slogging with 
khexedit. No scroll bar. Standing on down arrow is 16 bytes a line, some 
data even readable stuff in the first few pages, but its 0000 at 
0004:0000 offset yet. I give up on khexedit, there has to be a better 
tool for BIG files.

So I'll post this, see if the missus is ready for some coffee & see what 
else I can find to inspect this image file that at least has a 
pageup/pagedown function.
>
> Have a nice day :)
>
> Thomas



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