does "reiserfsck --rebuild-sb" require free space?

does "reiserfsck --rebuild-sb" require free space?

[Omry Yadan]

I have a partial image of a reiserfs partition which takes up all the 
space on the (reiserfs) parition it sits on.
there are 0 bytes free on that partition.
the image was created with dd, and I ran out space when creating it.
when I try to run
reiserfsck --rebuild-sb backup.img
I get the error
bwrite: write 4096 bytes returned -1 (block=16, dev=3): No space left on 
device

does that make sense?

     Omry.

Re: does "reiserfsck --rebuild-sb" require free space?

[Vladimir Saveliev]

Hello

On Mon, 2004-12-06 at 01:39, Omry Yadan wrote:
> I have a partial image of a reiserfs partition which takes up all the 
> space on the (reiserfs) parition it sits on.
> there are 0 bytes free on that partition.
> the image was created with dd, and I ran out space when creating it.
> when I try to run
> reiserfsck --rebuild-sb backup.img
> I get the error
> bwrite: write 4096 bytes returned -1 (block=16, dev=3): No space left on 
> device
> 
> does that make sense?
> 
Yes. That means that you have hit reiserfsck bug. Vitaly will contact
with you soon.


>      Omry.
> 

Re: does "reiserfsck --rebuild-sb" require free space?

[Vitaly Fertman]

Hello

On Monday 06 December 2004 16:04, Vladimir Saveliev wrote:
> Hello
>
> On Mon, 2004-12-06 at 01:39, Omry Yadan wrote:
> > I have a partial image of a reiserfs partition which takes up all the
> > space on the (reiserfs) parition it sits on.
> > there are 0 bytes free on that partition.
> > the image was created with dd, and I ran out space when creating it.
> > when I try to run
> > reiserfsck --rebuild-sb backup.img
> > I get the error
> > bwrite: write 4096 bytes returned -1 (block=16, dev=3): No space left on
> > device
> >
> > does that make sense?
>
> Yes. That means that you have hit reiserfsck bug. Vitaly will contact
> with you soon.

nothing about reiserfsck here. write to the file asks for some space on 
the host fs (which is reiserfs also) and there is no any. this looks like 
the correct behaviour for the fully packed fs as some data needs to be 
overwritten and access time needs to be updated. 

-- 
Thanks,
Vitaly Fertman

Re: does "reiserfsck --rebuild-sb" require free space?

[Vitaly Fertman]

On Monday 06 December 2004 18:17, Vitaly Fertman wrote:
> Hello
>
> On Monday 06 December 2004 16:04, Vladimir Saveliev wrote:
> > Hello
> >
> > On Mon, 2004-12-06 at 01:39, Omry Yadan wrote:
> > > I have a partial image of a reiserfs partition which takes up all the
> > > space on the (reiserfs) parition it sits on.
> > > there are 0 bytes free on that partition.
> > > the image was created with dd, and I ran out space when creating it.
> > > when I try to run
> > > reiserfsck --rebuild-sb backup.img
> > > I get the error
> > > bwrite: write 4096 bytes returned -1 (block=16, dev=3): No space left
> > > on device
> > >
> > > does that make sense?
> >
> > Yes. That means that you have hit reiserfsck bug. Vitaly will contact
> > with you soon.
>
> nothing about reiserfsck here. write to the file asks for some space on
> the host fs (which is reiserfs also) and there is no any. this looks like
> the correct behaviour for the fully packed fs as some data needs to be
> overwritten and access time needs to be updated.

the only thing that is not clear yet is why reiserfs needs some blocks 
here -- the journal space is reserved and the file data will be overwritten 
on-place, with no temporary locations. thus this could be a reiserfs bug 
or just-in-case reservation ... this needs to be checked.

you can free some space on the host reiserfs for now and write to the file
should succeed then.

-- 
Thanks,
Vitaly Fertman

Re: does "reiserfsck --rebuild-sb" require free space?

[Omry Yadan]

Vitaly Fertman wrote:

>On Monday 06 December 2004 18:17, Vitaly Fertman wrote:
>  
>
>>Hello
>>
>>On Monday 06 December 2004 16:04, Vladimir Saveliev wrote:
>>    
>>
>>>Hello
>>>
>>>On Mon, 2004-12-06 at 01:39, Omry Yadan wrote:
>>>      
>>>
>>>>I have a partial image of a reiserfs partition which takes up all the
>>>>space on the (reiserfs) parition it sits on.
>>>>there are 0 bytes free on that partition.
>>>>the image was created with dd, and I ran out space when creating it.
>>>>when I try to run
>>>>reiserfsck --rebuild-sb backup.img
>>>>I get the error
>>>>bwrite: write 4096 bytes returned -1 (block=16, dev=3): No space left
>>>>on device
>>>>
>>>>does that make sense?
>>>>        
>>>>
>>>Yes. That means that you have hit reiserfsck bug. Vitaly will contact
>>>with you soon.
>>>      
>>>
>>nothing about reiserfsck here. write to the file asks for some space on
>>the host fs (which is reiserfs also) and there is no any. this looks like
>>the correct behaviour for the fully packed fs as some data needs to be
>>overwritten and access time needs to be updated.
>>    
>>
It should write into the file, I don't see how the host file system is 
relevant here.
what if its a real partition and not an file containing an image?
in that case there is NO host file system at all..
if some data in the file must be overwritten, to make room for the file 
system overhead, so be it, but I don't see how trying to write outside
of the image make sense here. (unless there is a spacial treatment for 
images).



>
>the only thing that is not clear yet is why reiserfs needs some blocks 
>here -- the journal space is reserved and the file data will be overwritten 
>on-place, with no temporary locations. thus this could be a reiserfs bug 
>or just-in-case reservation ... this needs to be checked.
>
>you can free some space on the host reiserfs for now and write to the file
>should succeed then.
>  
>
Easier said than done, that file system has but one file, which is the 
image.
the only wat to 'free' up some space from it is to truncate the end if 
the image somehow.

Re: does "reiserfsck --rebuild-sb" require free space?

[Vitaly Fertman]

On Monday 06 December 2004 19:22, Omry Yadan wrote:
> Vitaly Fertman wrote:
> >On Monday 06 December 2004 18:17, Vitaly Fertman wrote:
> >>Hello
> >>
> >>On Monday 06 December 2004 16:04, Vladimir Saveliev wrote:
> >>>Hello
> >>>
> >>>On Mon, 2004-12-06 at 01:39, Omry Yadan wrote:
> >>>>I have a partial image of a reiserfs partition which takes up all the
> >>>>space on the (reiserfs) parition it sits on.
> >>>>there are 0 bytes free on that partition.
> >>>>the image was created with dd, and I ran out space when creating it.
> >>>>when I try to run
> >>>>reiserfsck --rebuild-sb backup.img
> >>>>I get the error
> >>>>bwrite: write 4096 bytes returned -1 (block=16, dev=3): No space left
> >>>>on device
> >>>>
> >>>>does that make sense?
> >>>
> >>>Yes. That means that you have hit reiserfsck bug. Vitaly will contact
> >>>with you soon.
> >>
> >>nothing about reiserfsck here. write to the file asks for some space on
> >>the host fs (which is reiserfs also) and there is no any. this looks like
> >>the correct behaviour for the fully packed fs as some data needs to be
> >>overwritten and access time needs to be updated.
>
> It should write into the file, I don't see how the host file system is
> relevant here.

host fs returns ENOSPC on the write call.

> what if its a real partition and not an file containing an image?
> in that case there is NO host file system at all..

and no such a problem at all.

> if some data in the file must be overwritten, to make room for the file
> system overhead, so be it, but I don't see how trying to write outside
> of the image make sense here. (unless there is a spacial treatment for
> images).

reiserfs_file_write needs to be checked as I already mentioned.

> >the only thing that is not clear yet is why reiserfs needs some blocks
> >here -- the journal space is reserved and the file data will be
> > overwritten on-place, with no temporary locations. thus this could be a
> > reiserfs bug or just-in-case reservation ... this needs to be checked.
> >
> >you can free some space on the host reiserfs for now and write to the file
> >should succeed then.
>
> Easier said than done, that file system has but one file, which is the
> image.
> the only wat to 'free' up some space from it is to truncate the end if
> the image somehow.

btw, it would be not bad to 'reiserfsck --check' the host reiserfs also.

-- 
Thanks,
Vitaly Fertman

Re: does "reiserfsck --rebuild-sb" require free space?

[Omry Yadan]

>>>you can free some space on the host reiserfs for now and write to the file
>>>should succeed then.
>>>      
>>>
>>Easier said than done, that file system has but one file, which is the
>>image.
>>the only wat to 'free' up some space from it is to truncate the end if
>>the image somehow.
>>    
>>
>
>btw, it would be not bad to 'reiserfsck --check' the host reiserfs also.
>
>  
>

I just did, it was reported to be clean. (no corruptions found).