Ext2 format in Slack 9.0
 

The format of the ext2 partition that Slackware 9.0 created during install is incompatible with the "normal" ext2 format. To wit, when I tried to resize the partition using parted, parted reported incompatible features in the Slack ext2.

Examining the man pages for mke2fs reveals a large number of options when formatting a partition with an ext2 filesystem. Does anyone have the intel on the choices that Slack 9.0 actually makes so I can create compatible ext2 partitions?

Any help would be most appreciated.

Rick

use "cfdisk" as root:)

Reply
 

The program cfdisk, like its siblings fdisk and sfdisk, are partition table manipulators. As such they can be used to specify the format of a partition in a partition table, as well as create and remove partitions. They do not format an actual partition. That must be done by another program, say mke2fs to format an existing partition with an ext2 or ext3 file system.

Parted can do both, manipulate a partition table, at least the MBR, and format the partition. However, it can only work with a partition having a "plain vanilla" ext2 file system. When I tried to resize my Slackware 9.0 ext2 partition, parted reported an error:" filesystem has incompatible features enabled." I have used parted successfully to resize other ext2 formatted partitions.

Slackware 9.0, during the setup phase of installation, formats a partition(s) with an ext2 file system that is/are not "plain vanilla", creating an incompatibility with programs that expect a "plain vanilla" ext2 file system. At least this is my observation-hypothesis.

To the partition table one ext2 file sytem is as good as another. After all, there is only one code for an ext2 filesystem.

Thus using cfdisk is a good suggestion but is, in fact, irrelevant to this situation.

Rick

point taken (i am reading up on filesystems at the mo; http://www.hallprogramming.com/algorithms/281.shtml ; its abit in-depth but im slowly learning)
i know this sounds silly but did you enable the said features or was that done by other cunning means?
ps. i never even knew there were added features for ext2:O

Reply 2
 

All of the cunning was done by the Slack 9.0 setup program. I take no credit.

To see the variables in an ext2 filesystem, take a look at man mke2fs. There are a lot.

One can use the program dumpe2fs to look at the parameters of extent ext2 file systems. For the Slack 9.0 ext2 filesystem dumpe2fs gave:

Filesystem features: dir_index filetype sparse_super

For the ext2 file in SuSE 8.2 dumpe2fs gave:

Filesystem features: filetype sparse_super

Is it the dir_index feature causing parted grief? I don't have a clue.

I am amazed that this issue isn't widespread.

Regards, Rick

just out of interest, I am using reisers fs, is this a good bad or indifferent fs when compared to ext2/3? It was offered to me during install and I just clicked "Y" to it. It is a quick journalised system but it isn't mentioned in the book i am reading.
sorry if i am not answering any of your questions!

I thought that the program was called mkfs. Where does that 'e' come from?
Anyway, the mkfs program is a front end script for the various
file system types that actually get called. On my system mkfs.ext2. Anyway, reading this script may give you the answer, if it calls the file-system specific builder with the same options that the setup program did.

The search order when looking for the fs-specific builder is
1st /etc/fs
2nd /etc
3rd $PATH

If the builder is in /etc/fs or /etc, it is itself a wrapper-script which may contain the options you are looking for.

Reply
 

For linux partitions I have only used the ext2 file system, the simple reason being maximum compatibility. Amusing in the light of circumstances.

On my system mkfs.ext2 is a symlink pointing to mke2fs. I cannot say if this is true with as-installed Slack 9.0 because I upgraded the e2fsprogs package. By the way, the ext2 compatibility problem was present before the upgrade and has remained after the upgrade.

The file /etc/fs doesn't exist on my system and nothing else appeared relevant in the /etc directory.

Isn't setup a shell script and within its bowels wouldn't there be the mke2fs command with the options?

Regards, Rick

From what I understand, it is not possible to change the options of a file-system once it is in use due to the many ways in which the files themselves are ordered by the file system. it is however possible to create a new "vanilla" mirror and backup all your files, then change the non-standard partition (format it then re-size it) and restore. I cannot find any references for the options you mentioned and unfortunately this is the only suggestion I can put forward.

edit: try these people: http://www.drivelabs.us/ !!!!!

Reply
 

Thanks LinFreak.

I tried for several hours today to ascertain what options setup used in creating the ext2 file system, but to no avail. I find it a bit irritating that Slackware doesn't document what they did since it is non-standard.

We are in agreement. I see no alternative but to transfer the data, then delete-format-resize the partition. I think the transfer would have to be a copy. If one used a program like partimage, the file system structure would probably be preserved, thus making it impossible to restore to a "plain vanilla" ext2 partition.

Moral of the story -- always have the partitions large enough to begin with, even if it means upgrading your hard drive -- Pay me now or pay me later.

When you become the file system guru, please give me the intel on what Slackware did.

Fair winds and following seas, Rick

I have to agree. In my experience, copying anything in linux works, ie. if you copy your /etc, /usr and /home directories then restore them after re-installing the distribution, everything should work as normal (always has for me).
I can't say wether it will work for the entire filesystem (/boot, /dev, /var etc.) but if this is all done without changing the mbr, then I can't see any reason why not!
good luck!