Hmm, now I'm throughly confused :-( What is the "union" in here then ?
Is it that a lookup for a top-level component searches all file system
in that list, or does it simply mean that all the file systems are
internally linked to the same place, but only one of them is truly
visible ?
E.g., given
# mount /dev/a /mnt
# mkdir -p /mnt/foo/blah /mnt/bar
# umount /dev/a
# mount /dev/b /mnt
# mkdir -p /mnt/foo/zulu /mnt/baz
# mount -o union /dev/a /mnt
# cd /mnt/foo/blah works ?
# cd /mnt/foo/zulu works too ? (no, I guess)
# cd /mnt/baz works ?
# cd /mnt/bar works too ?
# cd /mnt; touch file works ? on which device is the file created ?
# cd /mnt/foo; touch file works ?
# cd /mnt/foo/blah; touch file works ?
# cd /mnt/foo/zulu; touch file works too ? (no, I guess)
Maybe you should define what you mean by "union" ... seems that
everybody has a slightly different idea of what it should mean.
- Werner
-- _________________________________________________________________________ / Werner Almesberger, ICA, EPFL, CH werner.almesberger@ica.epfl.ch / /_IN_N_032__Tel_+41_21_693_6621__Fax_+41_21_693_6610_____________________/- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/