I installed 32-bit Fedora Core 5 on an Athlon-64 box. I intended this installation to co-exist with a 64-bit Fedora Core 3 installation. The two installations share a /home ext3 partition and the swap partition. This is often how I do upgrades: a dual boot system with both old and new bootable. The problem is that the FC5 installation did something to the /home partition that prevents the FC3 from mounting it. When I manually try a mount of /home from FC3, the useless mount-failure message is preceded by these messages. I think that they are the key: inode_doinit_with_dentry: context_to_sid(system_u:object_r:home_root_t:s0) returned 22 for dev=hda5 ino=2 inode_doinit_with_dentry: context_to_sid(system_u:object_r:home_root_t:s0) returned 22 for dev=hda5 ino=2 (In dmesg, these two messages were preceded by these that might be relevant: kjournald starting. Commit interval 5 seconds EXT3 FS on hda5, internal journal EXT3-fs: mounted filesystem with ordered data mode. SELinux: initialized (dev hda5, type ext3), uses xattr ) (The useless mount failure message is: mount: wrong fs type, bad option, bad superblock on /dev/hda5 or too many mounted file systems This message is disgracefully non-specific.) I think that this is a problem with SELinux. The following thread looks relevant but unhelpful: http://www.redhat.com/archives/fedora-selinux-list/2006-April/msg00002.html It provides a solution (I hope) for FC4 but FC3 would not have such an update. I tried using enforcing=0 on the FC3 kernel command line, but nothing changed. I thought ext3 was compatible between Fedora releases. Unfortunately, SELinux seems to have made things a lot more brittle. ==> Is there something simple that I can do to allow the existing /home ext3 partition to be shared between FC3 and FC5? ==> What does the error message mean? inode 2 is the root of the filesystem. It appears that kernel routine inode_doinit_with_dentry is calling context_to_sid and context_to_sid is returning EINVAL (because the context was invalid). But even knowing that, I don't know what it actually means or is caused by. (By the way, if FC5 worked well, it might not matter. Unfortunately, there is some regression in xorg that prevents dual-head working properly on FC5 where it did on FC3.)