Bug 343083

Summary:	ext4 corrupts large files...
Product:	Gentoo Linux	Reporter:	Alireza Torabi <alireza.torabi>
Component:	[OLD] Core system	Assignee:	Gentoo Linux bug wranglers <bug-wranglers>
Status:	RESOLVED NEEDINFO
Severity:	critical
Priority:	High
Version:	unspecified
Hardware:	AMD64
OS:	Linux
Whiteboard:
Package list:		Runtime testing required:	---

Description Alireza Torabi 2010-10-28 14:28:05 UTC

just copied a 12GB _sparse_? file to a new created ext4 filesystem on a 2.6.35.4 kernel. md5sum -ed it and everytime it's a new hash! original file's md5sum is always calculated corretly.

Reproducible: Always

Steps to Reproduce:
1. copy a large enough _sparse_? file to an ext4 filesystem. (12GB was my file)
2. md5sum the file copied.
3. hash is different everytime you do it.

Actual Results:  
md5 hash changes everytime it's run for copied file.

Expected Results:  
md5 hash should calculate the same hash every time.

Comment 1 Jeremy Olexa (darkside) (RETIRED) archtester

2010-10-28 16:43:10 UTC

It is my understanding that sparse files are not ever copied sparsely unless you tell the app to do it. tar -S, cp --sparse, rsync --sparse, etc. What did you do?

Comment 2 Alireza Torabi 2010-10-28 16:47:14 UTC

I've tried both with and without --sparse. It shouldn't matter anyway as the content of a file should still remain the same no matter how they are stored on the filesystem. If ext4 wants to treat them differently, then fine but when I read my file back I well expect to get the same file.

Comment 3 Chí-Thanh Christopher Nguyễn gentoo-dev

2010-10-31 18:45:02 UTC

I think it could be a problem of md5sum rather than of ext4. Does the same happen if you run:

# cat filename | md5sum

Comment 4 Alireza Torabi 2010-10-31 19:35:34 UTC

md5sum and sha256sum both generate random messages every time run on the copied version. They both agree on the message computed when run on the original file (stored on an ext3).

Comment 5 Jeroen Roovers (RETIRED) gentoo-dev

2010-11-01 20:59:41 UTC

Please copy the output of `tune2fs -l /dev/<your-ext4-disk>' into a comment.

Comment 6 Alireza Torabi 2010-11-02 10:58:22 UTC

I've updated the kernel to 2.6.35.7 and reformatted the file system ext3 now. I'll report back once I've added a new ext4 with the same problem, hopefully the problem will not be showing on the new kernel.

Comment 7 Jeroen Roovers (RETIRED) gentoo-dev

2010-11-02 17:50:23 UTC

Then please reopen this bug report when you have more information.