O site do Arch Linux tem uma notícia que explica isso:
News: filesystem upgrade - manual intervention required
2011-12-20 - Tom Gundersen
When upgrading to
filesystem-2011.12there will be a conflict with/etc/mtab.Install the package as follows:
pacman -S filesystem --forceIt is strongly advised to avoid the
--forceor-fswitch as it is not safe. However, in this particular case it is needed as deleting/etc/mtabmanually would break pacman.The reason for the conflict is that the file used to be generated at boot and hence not owned by any package. Now it is a symlink to
/proc/self/mountsowned byfilesystem. This change means thatinitscriptsno longer requires write access to the rootfs (though other packages might).