On Wed, 24 Oct 2007, Oliver Fromme wrote: > Dmitry Marakasov <amdmi3_at_amdmi3.ru> wrote: > > I was told long time ago that -ounion is even > > more broken than unionfs. > > That's wrong. The union mount option was _never_ really > broken. I'm using it for almost as long as FreeBSD exists. I recently noticed the following bugs in -ounion (which I've never used for anything except testing): (1) It is broken for all file systems except ffs and ext2fs, since all (?) file systems now use nmount(2) and only these two file systems have "union" in their mount options list. It is still in the global options list in mount/mntopts.h, but this is only used with mount(2). The global options list in mount/mntopts.h has many bogus non-global options, and even the global options list in kern/vfs_mount.c has some bogus non-global options, but "union" actually is a global options. ext2fs loves "union" more than ffs -- although its options list is less disordered than ffs's, it has enough disorder to have 2 copies of "union". (2) After fixing (1) by not using nmount(2), following of symlinks works strangely for at least devfs: (a) a link foo -> zero (where zero doesn't exist in the underlying file system) doesn't work. mount(1) says that the lookup is done in the mounted file system first. (b) a link foo -> ./zero works. This is correct. Now I wonder if it would work if zero existed only in the underlying file system. Have you noticed these bugs? (2) is presumably old. BruceReceived on Thu Oct 25 2007 - 16:34:15 UTC
This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:39:20 UTC