[olug] Argh!

[Nick Walter]

Opening a file read/write on a full partition and then writing to it will
not cause any particular problem, unless the application attempts to grow
the file by writing beyond the existing EOF.  The growing will fail, but
even then the existing contents of the file will be unharmed.  I'm speaking
from experience as I once had to debug an application I'd written that was
running into exactly this problem.  If requested, I can provide a test
scenario + source code to replicate this behavior.

I'm also curious how having a full partition will impact memory/swap?  Is
this another case of badly behaved applications or some naughty behavior of
the Linux kernel that I've never encountered?

Nick Walter


----- Original Message -----
From: "Sam Tetherow" <tetherow at nol.org>
To: <olug at olug.org>
Sent: Sunday, December 15, 2002 4:30 PM
Subject: Re: [olug] Argh!


> Nick Walter wrote:
>
> >I've filled up partitions in my time, even filled up / on a couple of
> >occassions.  RH Linux always impressed me by not crashing or having
horrible
> >seizures when it happened.  I've seen other Unices do a lot lot worse in
the
> >same situation.
> >
> Run it a little bit longer, horrible things will start to happen :).
>  Once mem and swap are full there isn't much you can do.
>
> >The only thing I can think of is that Mozilla perhaps erases/re-writes
the
> >bookmarks when you edit them?  I'm 100% in agreement with Adam that
nothing
> >in Red Hat or Mandrake Linux will arbitrarily delete files just because a
> >partition is full.  The only thing that should happen is some processes
> >dying or freezing because they can't complete I/O.
> >
>
> It is poorly written applications that cause this.  As the program
> exists it opens the file to rewrite the data, when the open command is
> given there is no error since you are not trying to write anything to
> disk.  In doing so you have now managed to set the file marker at byte
> zero in the file.  You now try to write but alas there is no room on the
> disk so you get an error and the program will exit meanwhile leaving the
> file marker at 0, effectively wiping the file.  The better way to do
> this is to create a second file, write out the new data and then rename
> the file with the old filename.
>
> >
> >Nick Walter
> >
> >----- Original Message -----
> >From: "Adam Haeder" <adamh at omaha.org>
> >To: <olug at olug.org>
> >Sent: Saturday, December 14, 2002 8:30 PM
> >Subject: RE: [olug] Argh!
> >
> >
> >
> >
> >>What do you mean wiped clean? Even if the partition fills up, there's no
> >>process that says "better delete everything in Adam's home directory".
How
> >>did the data get deleted?
> >>
> >>-----Original Message-----
> >>From: Adam Lassek [mailto:hayai2 at cox.net]
> >>Sent: Saturday, December 14, 2002 9:22 PM
> >>To: olug at olug.org
> >>Subject: [olug] Argh!
> >>
> >>
> >>This is one thing about Linux that has always pissed me off. The
> >>partition my home directory was in filled up (not even sure how that
> >>happened yet) and so every bookmark I've ever saved in Mozilla, gftp or
> >>whatever has been completely wiped clean. Why does that even happen?
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> >>
> >>
> >>
> >
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> >
>
>
>
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