fsfuzzer: exabyte file sizes

fsfuzzer: exabyte file sizes

[Dan Carpenter]

[-- Attachment #1: Type: text/plain, Size: 1405 bytes --]

I'm messing with fsfuzzer and it created a filesystem with a huge
exabyte file which is larger than ext4 supports.

root@elgon:/tmp# mount -o loop ext4_exabyte_file.img mnt/
root@elgon:/tmp# ls -l mnt/
ls: cannot access mnt/config.h: Input/output error
ls: cannot access mnt/configure: Input/output error
total 114898965103020
-rw-r--r--     1 root root              267551 Nov 21 18:03 aclocal.m4
-rw-r--r--     1 root root                 216 Nov 21 18:03 AUTHORS
-rw-r--r--     1 root root            13893752 Nov 21 18:03 ChangeLog
-rw-r--r-- 10753 root  175               29713 Nov 21 18:03 c?nfig.log
-rwxr-xr-x     1 root root               44878 Nov 21 18:03 config.guess
-?????????     ? ?    ?                      ?            ? config.h
-rw-r--r--     1 root root                1882 Nov 21 18:03 config.h.i?~
-rw-r--r--     1 root root 9583660007044417438 Nov 21 18:03 config.h.in
-rwxr-xr-x     1 root root               33400 Nov 21 18:03 config.status
-rwxr-xr-x     1 root root               33387 Nov 21 18:03 config.sub
-?????????     ? ?    ?                      ?            ? configure
drwx------     2 root root               16384 Nov 21 18:03 lost+found
root@elgon:/tmp# 

I've uploaded the corrupted filesystem image to:
http://smatch.sf.net/upload/ext4_exabyte_file.img

Not a huge deal, but I thought I'd report it anyway.

regards,
dan carpenter

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 836 bytes --]

Re: fsfuzzer: exabyte file sizes

[Andreas Dilger]

On 2011-11-22, at 3:10 AM, Dan Carpenter wrote:
> I'm messing with fsfuzzer and it created a filesystem with a huge
> exabyte file which is larger than ext4 supports.
> 
> root@elgon:/tmp# mount -o loop ext4_exabyte_file.img mnt/
> root@elgon:/tmp# ls -l mnt/
> ls: cannot access mnt/config.h: Input/output error
> ls: cannot access mnt/configure: Input/output error
> -rw-r--r--     1 root root 9583660007044417438 Nov 21 18:03 config.h.in

I don't know that there is much to be done with this at the ext4 level.
Of course e2fsck should fix this, but that isn't what is being tested here.
I think the best that can be expected of ext4 is that it doesn't crash or
lock up when encountering such files.

It wouldn't be a terrible exercise to run fsfuzzer against some filesystem
and then run e2fsck on it.  It should be able to fix any problem in the
first run, and the filesystem should be totally clean on the second run.

Cheers, Andreas