Mounting a big ext2fs partition on a USB drive in FreeBSD
Originally posted on December 14, 2008.
I have a Maxtor OneTouch 4 Plus external USB drive, 750gb, that I wanted to connect to my home server running FreeBSD 7.0. I planned on using the drive for holding music and media, using the FreeBSD server as a media hub running Mediatomb and NFS/SMB shares.
In planning the venture, I needed the hard drive’s format to be as universally compatible and as universally stable as possible. I needed to be able to reliably interact with the drive under FreeBSD and Linux, as well as OS X and Windows (should the need ever arise, I want to be ready).
After some thought, I ended up settling on ext2 for the drive’s file system. I chose ext2 because:
- It is fairly universal, in that it can be mounted and used reliably from most OSs.
- I did not want to use FAT32; plus, FreeBSD’s msdosfs driver could not mount the drive properly (even with the -o large switch).
- Did not want to use NTFS because of general shakiness on any non-Windows platform.
- I initially tried UFS, but gave up after repeated failed attempts to get FreeBSD to partition and label it properly. (Not sure why; suspect the drive’s detected geometry may have been an issue.)
- Considered ZFS but decided I don’t want to be that cutting-edge; plus I wouldn’t have a use for most of its extended functionality. (I just need a basic filesystem.)
- Considered HFS+ but FreeBSD support is shaky (old driver, could not get it to compile on 7.0).
So, I plugged the drive into an Ubuntu Ibex box, formatted it into one ext2 partition and plugged it in to the FreeBSD box.
mount -t ext2fs /dev/da0s1 /mnt/media
So far, so good. The output of the mount command shows that the drive is there and mounted. But then:
cd /mnt ls -la ls: media: Bad file descriptor
For some reason, the mount point could not be listed.
After some research, I came across this bug report that described the problem in greater detail. Basically, newer versions of Linux seem to format ext2fs partitions using a 256-byte inode size, versus the previous default of 128 bytes, which is what the FreeBSD ext2fs driver expects it to be.
Fixing The Problem
To fix it, you’ll apply a patch by Josh Carroll, who posted it in the bug report linked above. Under a standard FreeBSD 7.0 installations, the commands will be something like this (as root):
cd /usr/src/sys/gnu/fs cp -R ext2fs ext2fs.orig cd ext2fs fetch https://neveradudelikethisone.com/files/ext2fs.diff patch <ext2fs.diff cd /usr/src make buildkernel KERNCONF=GENERIC && make installkernel KERNCONF=GENERIC
If all goes well, you should then be able to restart, mount the drive, and have it work as expected. Good luck!