>Number:         35704
>Category:       kern
>Synopsis:       problems in a full ffs file system
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Feb 19 11:05:00 +0000 2007
>Originator:     Peter
>Release:        NetBSD 3.0
>Organization:
>Environment:
System: NetBSD performance_c1 3.0 NetBSD 3.0 (MYKERNEL) #1: Fri Feb 16 14:00:57 2007 admin@NETBSD:/usr/NetBSD-3.0/cross/i386/obj/sys/arch/i386/compile/MYKERNEL
i386
>Description:
Hello,

we have a Problem in NetBSD 3.0 and ffs filesystem.
If we fill as a root user a ffs file system until no space is available,
we get corrupted files.
        /home: write failed, file system is full
        mount:
        /dev/wd0g     970M     970M      -48M   105%    /home
After that, the root user is able to create files like:
        echo 'aaaaaaaaa' > ffs_test
this file (ffs_test) is ok.
After making this file bigger with:
        cat ffs_test >> ffs_test
this file (ffs_test) is corrupt.
This error occurs if we mounted this filesystem in softdep-mode and
default-mode. With mounting this filesystem in synchronous mode,
this error DOES NOT occure. Also by filling the filesystem as a non
root user, who is not able to write more then 100 %,
the error DOES NOT occure.
On other systems we get even coredumps after panic
and some other problems occured (e.g. binaries did not start anymore).

>How-To-Repeat:
* login as root user
* make your filesystem full until:
       /home: write failed, file system is full
* create a new file:
       echo 'aaaaaaaaa' > ffs_test
* make this file bigger with:
       cat ffs_test >> ffs_test

>Fix: