Messages in this thread | | | Date | Tue, 28 Oct 2014 19:10:36 +0100 | From | Tim Tassonis <> | Subject | overlayfs: "filesystem of lowerdir is not supported" on cdrom |
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Hi
Just installed 3.18-rc2 and tried to test the overlayfs stuff:
$ mkdir /ovtmp $ mount -t tmpfs tmpfs /ovtmp/ $ mkdir /ovtmp/work $ mkdir /ovtmp/upper $ mkdir /cdrw $ mount /dev/sr0 /mnt $ mount |egrep "ovtmp|sr0"
/dev/sr0 on /mnt type iso9660 (ro,relatime) tmpfs on /ovtmp type tmpfs (rw,relatime)
$ mount -t overlayfs overlayfs \ -olowerdir=/mnt,upperdir=/ovtmp/upper,workdir=/ovtmp/work /cdrw
mount: wrong fs type, bad option, bad superblock on overlayfs, missing codepage or helper program, or other error
In some cases useful info is found in syslog - try dmesg | tail or so.
$ dmesg |tail
[ 3266.793218] overlayfs: filesystem of lowerdir is not supported
However, the doc in Documentation/filesystems/overlayfs.txt states:
"The lower filesystem can be any filesystem supported by Linux and does not need to be writable. The lower filesystem can even be another overlayfs. The upper filesystem will normally be writable and if it is it must support the creation of trusted.* extended attributes, and must provide valid d_type in readdir responses, so NFS is not suitable."
So: Is the documentation wrong, the error message in dmesg wrong, or have missed something completely?
Kind regards Tim
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