Bug 875605 - ramdisk /etc/mke2fs.conf [fstypes] stanza lacks "ext2" tag with inode_size=128
ramdisk /etc/mke2fs.conf [fstypes] stanza lacks "ext2" tag with inode_size=128
Status: CLOSED NOTABUG
Product: Fedora
Classification: Fedora
Component: e2fsprogs (Show other bugs)
18
i686 Unspecified
unspecified Severity low
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Assigned To: Eric Sandeen
Fedora Extras Quality Assurance
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Depends On:
Blocks:
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Reported: 2012-11-12 02:35 EST by Paul Franklin (RHlists)
Modified: 2012-11-13 11:24 EST (History)
8 users (show)

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Doc Type: Bug Fix
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Last Closed: 2012-11-13 11:24:36 EST
Type: Bug
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Description Paul Franklin (RHlists) 2012-11-12 02:35:33 EST
Description of problem:

I am not a Fedora expert so I apologize if you don't think
this is a bug.  I am not so good at explaining things too.

For reasons which don't matter, for years I have created an
empty ext2 partition and then installed a Fedora onto it.
(This is so my real /home wouldn't be affected if something
went wrong, and also so that other operating systems could
mount that new ext2 Fedora partition, read it and write it.)

The last Fedora which did that was Fedora 14 and so I
haven't installed any newer Fedora since then.  But now I
need new programs, which are only in F18, so I've been
trying for weeks to install it, even a preliminary version.

Finally today I was able to install F18-Beta-TC8 and login.

The clue in bugzilla.redhat.com/show_bug.cgi?id=871104#c6
told me about /etc/mke2fs.conf (which I had never heard of)
and so I was able to edit that file (from the ctrl-alt-f2
anaconda shell) before I clicked in the custom partitioning
window and told it to format the new ext2 root partition.

I added this to the [fstypes] stanza:

    ext2 = {
        inode_size = 128
    }

(and I put it ahead of the ext3 line, if it matters).

That's what I claim the bug is, that the /etc/mke2fs.conf
[fstypes] stanza doesn't have an ext2 tag, which specifies
that the inode_size should be 128.  All the older ext2
filesystems I have examined have an inode_size of 128 and I
have older operating systems which won't mount the new F18
"ext2" filesystem if it is created with an inode_size of
256, which is the default unless a specific filesystem tag
overrides it (as I now do).

You understand I am talking about the /etc/mke2fs.conf file
in the initial ramdisk image, the initrd.img I boot with.

If you don't think this is a bug, and don't want to alter
your ramdisk /etc/mke2fs.conf file, can I please ask you to
tell me how I can make an updates.img file which has my
altered /etc/mke2fs.conf file in it, so I don't need to do
the edit manually every time I install Fedora 18?

Thank you.


Version-Release number of selected component (if applicable):
F18-Beta-TC8

How reproducible:
always

Steps to Reproduce:
1. use "custom partitioning" screen to format an ext2 partition
2. use "tune2fs -l" to examine the inode_size of it
3.
  
Actual results:
anaconda-created ext2 filesystem has inode_size of 256

Expected results:
anaconda-created ext2 filesystem has inode_size of 128

Additional info:
Comment 1 Chris Lumens 2012-11-12 08:53:54 EST
The /etc/mke2fs.conf file comes from the package.  We don't specifically write one out in lorax.
Comment 2 Paul Franklin (RHlists) 2012-11-12 11:15:29 EST
Thank you for the response.

If the e2fsprogs maintainer doesn't consider it a bug, will
one of you tell me how to put my modified /etc/mke2fs.conf
file into an updates.img file?  It should be possible but I
don't know how.  Thanks.
Comment 3 Eric Sandeen 2012-11-13 11:24:36 EST
The default inode size changed from 128 to 256 4 years ago.  When you say:

"I have older operating systems which won't mount the new F18
"ext2" filesystem if it is created with an inode_size of
256, which is the default unless a specific filesystem tag
overrides it (as I now do)."

just how old are those operating systems; older than I think 2.6.10?

Anyway, defaults changed upstream 4 years ago:

commit b1631cce648ee87e39b602899d77ad59a81acc66
Author: Theodore Ts'o <tytso@mit.edu>
Date:   Sun Jan 27 19:30:27 2008 -0500

    Create new filesystems with 256-byte inodes by default
    
    This makes it easier to upgrade to ext4 in the future, and it speeds
    up extended attributes handling --- important on SELinux systems!
    
    Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

I am going to say NOTABUG; upstream made the decision 4 years ago, and kernels in the past 7 or 8 years CAN handle it, so I think this is a case of you just needing special configuration for compatibility with your very old systems.

If you have questions about update images etc, I expect the fedora mailing lists or forums would be the right place for that.

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