Hi, I have a Debian wheezy (IP 1.2.3.158 in the example below) server running as NFS v4 server. Now I want to mount a directory via NFS v4 read-only and put a tmpfs on top via aufs. When I try to access a file in /sysroot/boot (for e.g. with grep) I get the error message "Not a directory". But it's a file!
Here's what I did on my NFS client: mkdir /sysroot mount -oro 1.2.3.158:/fai/nfsroot /sysroot mkdir -p /live/image mount --move /sysroot /live/image mkdir /cow mount -n -t tmpfs tmpfs /cow mount -t aufs -o dirs=/cow=rw:/live/image=rr aufs /sysroot Now I try to access a file: grep AUFS_IN /sysroot/boot/config-3.2.0-2-amd64 grep: /sysroot/boot/config-3.2.0-2-amd64: Not a directory Here's some strace output of a cat command which produces the same error message execve("/bin/cat", ["cat", "/sysroot/boot/config-3.2.0-2-amd"...], [/* 17 vars */]) = 0 brk(0) = 0x177a000 . . . fstat(1, {st_mode=S_IFCHR|0600, st_rdev=makedev(4, 1), ...}) = 0 open("/sysroot/boot/config-3.2.0-2-amd64", O_RDONLY) = -1 ENOTDIR (Not a directory) write(2, "cat: ", 5) = 5 write(2, "/sysroot/boot/config-3.2.0-2-amd"..., 34) = 34 write(2, ": Not a directory", 17) = 17 This error occurs on Debian wheezy with aufs 3.2-20120312 and kernel 3.2.0-2-amd64. [~]# dmesg | grep aufs [613334.618000] aufs: module is from the staging directory, the quality is unknown, you have been warned. [613334.619541] aufs 3.2-20120312 [613334.620163] aufs test_add:261:mount[23264]: uid/gid/perm /live/image 0/0/0755, 0/0/01777 [~]# uname -r 3.2.0-2-amd64 If I do the same on a NFS client running Debian squeeze with aufs 2-standalone.tree-32-20100125 and kernel 2.6.32-5-amd64 (the NFS v4 server is still Debian wheezy) everything work fine and I can access all files in /sysroot/boot/ Any ideas how to fix this? More ideas how to debug? -- regards Thomas ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/