Re: [Bug-ddrescue] Logfile won't write: claims drive is read-only

[nn]

HI Jeffrey,

I'm posting this to the email-list too, as it seems you forgot to answer
it in the to-filed.


On 24.04.2016 00:22, Jeffrey Carlson wrote:
> Do you know what will happen if I press Q+ENTER now? Will my rescue
> not be resumable, or will I just have to redo the last thirty seconds
> of scanning and splitting blocks? The prompt I'm answering is
>
> ddrescue: Error opening logfile 'baby3.logfile' for writing.:
> Read-only file system
> Fix the problem and press ENTER to retry, or Q+ENTER to abort.

The short answer is: yes! Your progress will be lost.
But it looks like it's a bit more complicated. As it seems that there IS
already a logfile which was created before, but all of a sudden is
unwriteable.

So there are different ways something went wrong.

You mentioned that there was an input/output error. I guess you did not
know which one of the drives (either the input drive or the output
drive) failed?
My guess is that the output drive somehow failed and messed up either
file permissions or simply messed up the whole logfile.

This is something for Antonio! He might want to see the logfile to seem
what might've gone wrong. Please wait until he tells you to send him
your logfile.

Or simply, the drive you are writing the files to is full. Unlikely, as
you said you created files and copied test files and played around with
the space of the drive.

Let's see:
>
> Now for your question: I've invoked a few runs of ddrescue and
> interrupted them when they seemed to hang: here's I think all of them.
>
> address@hidden:/media/jeff/f1611274-1f7d-4b32-9475-1ac91c0da6d2$ sudo
> ddrescue -n -d -r1 /dev/sdc2 baby3.img baby3.logfile
> address@hidden:/media/jeff/f1611274-1f7d-4b32-9475-1ac91c0da6d2$ sudo
> ddrescue -R -n -r1 -c64 /dev/sdc2 baby3.img baby3.logfile
> address@hidden:/media/jeff/f1611274-1f7d-4b32-9475-1ac91c0da6d2$ sudo
> ddrescue -R -c64 /dev/sdc2 baby3.img baby3.logfile
> address@hidden:/media/jeff/f1611274-1f7d-4b32-9475-1ac91c0da6d2$ sudo
> ddrescue -i 7435817400 -c64 /dev/sdc2 baby3.img baby3.logfile
> address@hidden:/media/jeff/f1611274-1f7d-4b32-9475-1ac91c0da6d2$ sudo
> ddrescue -n -d /dev/sdc2 baby3.img baby3.logfile
> address@hidden:/media/jeff/f1611274-1f7d-4b32-9475-1ac91c0da6d2$ sudo
> ddrescue -R -d /dev/sdc2 baby3.img baby3.logfile
>
Just to make sure. When did the write error occur? After which command?
I guess the first one worked fine, but did not work after that?

Everything looks OK, but this command:
"sudo ddrescue -i 7435817400 -c64 /dev/sdc2 baby3.img baby3.logfile"
Where did you come up with the input position? I personally would not
recommend to use the -i option unless you REALLY, REALLY know what it
does and how to use it. (as referred to in the manual examples!)

> The first one recovered most of the data, the last one recovered about
> 2 MB, and the runs after the first with -n ended very early.
>
> These have all been invoked from the base directory of the partition I
> want to write to, which is currently /dev/sdd and mounted at
> /media/jeff/[long hex name]. I believe they are all trying to create
> an image file, baby3.img, on this disk.

Yes, you actually wrote to the same file in all runs. With a regular
logfile this is OK and the way ddresuce should be used.

>
> I've been able to convince myself I'm really able to write to the
> partition I want to write to by cutting and pasting small files there.
> These give no error messages, and the partition shows up on gparted
> without the little key symbol that indicates read-only. Doing ls -l
> shows me that I am the owner and have all permissions for the things
> on this partition.

OK, try this:
1. Give us the output of ls -l from the "/media/jeff/[long hex name]"
directory you wrote the imagefile to. Just to see what file permissions
are set on the log file.

2. Try to copy the logfile somewhere else (preferably your home
directory) and then run ddrescue with this command

address@hidden:/media/jeff/f1611274-1f7d-4b32-9475-1ac91c0da6d2$ sudo
ddrescue -n -d -r1 /dev/sdc2 baby3.img /home/[yourusername]/baby3.logfile

Notice the /home/[username]/ that will point it to your home directory.
I'm sure it is "/home/jeff/". Of course you can copy the logfile
wherever you want. See if it still give the write error.

3. You should take a look on the logfile itself. Try to open it with a
text editor and see if it looks similiar to the example given in the
manual
(https://www.gnu.org/software/ddrescue/manual/ddrescue_manual.html#Mapfile-structure)

If it is garbled or does not look anything like the example the logfile
might be corrupted?

If it is a regular logfile then I'd recommend waiting for Antiono's
answer and email him the baby3.logfile, when he is requesting it.

>
> It's good to know I can write the log file anywhere. Is there a way I
> can switch the target of the *current* run (which gives me the prompt
> above) to my local drive to circumvent the lack of writeability that
> ddrescue is claiming?
>

Yes, see the example above. (#2)

>
> Thank you again,
> Jeff
>
>
>
>
>
> On Sat, Apr 23, 2016 at 4:21 AM, nn <address@hidden
> <mailto:address@hidden>> wrote:
>
>     Hi Jeffrey,
>
>     could you please provide the command you invoked ddresuce, e.g.
>
>     ddrescue -d -r3 /harddrive baby3.img baby3.logfile
>
>     ?
>
>
>     Also: From which directory are you starting the process. I guess it's
>     your home directory, but you maybe did try to invoke ddrescue from
>     either the drive you want to write to or anywhere else?
>
>     I believe you tried to write not an image file, but directly to the
>     external disk? It is not clear from your description.
>
>     This might help in further assessing your problem.
>
>     Just to give you an insufficient answer. You might write the logfile
>     anywhere you want, e.g. your Ubuntu Desktop
>     (/home/yourusername/Desktop)
>     and continue later. Just in case you want to make sure that you are
>     really allowed to write to the disk.
>
>