256-byte inode support

[Wesley Shields]

On Tue, Sep 09, 2008 at 02:53:51PM +0300, Kostik Belousov wrote:
> On Sun, Sep 07, 2008 at 11:07:47AM -0400, Wesley Shields wrote:
> > On Sat, Sep 06, 2008 at 07:26:27PM -0400, jT wrote:
> > > hackers,
> > > 
> > >     since tytso had updated ext3 -- i've noticed that i can't use my
> > > 265-byte inode ext3 drives -- is there any effort to update it?  If
> > > not -- if you know where i should attempt to start please let me know
> > > so i can start working on support (i have a few other people i know
> > > interested in this) -- thanks and hope everyone is well
> > 
> > There was a PR submitted for it and eventually a patch added to the PR.
> > I've tested the patch given in the URL at the port and it works.  We
> > will start to see more of this as the newer version becomes more common
> > in the wild.
> > 
> > http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/124621
> > 
> > Would be nice to see this fixed in 7.1 but it may be too late for that.
> 
> What was the reason for increasing inode size ? I think it is rather
> pointless to increase the size without using newly added space for some
> data. Is inode format the same for the first 128 bytes, and does data
> at the second 128 bytes should be used to correctly interpret inode ?

I honestly don't know the answer.  Though I do agree that it is
pointless to increase the size without using the new space.

All I know is that I was unable to read an ext filesystem made with -I
256 (which is the default when using the most recent
sysutils/e2fsprogs).

wxs at ack ~ % truncate -s 1G ext-128
wxs at ack ~ % truncate -s 1G ext-256
wxs at ack ~ % sudo mdconfig -a -t vnode -f ext-128 -s 1G
md0
wxs at ack ~ % sudo mdconfig -a -t vnode -f ext-256 -s 1G
md1
wxs at ack ~ % sudo kldload ext2fs
wxs at ack ~ % mke2fs -I 128 /dev/md0
mke2fs 1.41.0 (10-Jul-2008)
mke2fs: Permission denied while trying to determine filesystem size
wxs at ack ~ % sudo mke2fs -I 128 /dev/md0
mke2fs 1.41.0 (10-Jul-2008)
Filesystem label=
OS type: FreeBSD
Block size=4096 (log=2)
Fragment size=4096 (log=2)
65536 inodes, 262144 blocks
13107 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=268435456
8 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks: 
	32768, 98304, 163840, 229376

Writing inode tables: done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 27 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.
wxs at ack ~ % sudo mke2fs /dev/md1
mke2fs 1.41.0 (10-Jul-2008)
Filesystem label=
OS type: FreeBSD
Block size=4096 (log=2)
Fragment size=4096 (log=2)
65536 inodes, 262144 blocks
13107 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=268435456
8 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
	32768, 98304, 163840, 229376

Writing inode tables: done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 37 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.
wxs at ack ~ % sudo mount -t ext2fs /dev/md0 /mnt/ext2-128 
wxs at ack ~ % sudo mount -t ext2fs /dev/md1 /mnt/ext2-256 
wxs at ack ~ % ls /mnt/ext2-128 
lost+found/
wxs at ack ~ % ls /mnt/ext2-256
ls: /mnt/ext2-256: Bad file descriptor
wxs at ack ~ % 

-- WXS