Hi Alexander Viro et al, This is an escalation of Debian Bug #669314 http://bugs.debian.org/669314, which I will re-elaborate in this email for your convenience. You committed a change to the way the linux kernel reports NFS mounts - now with a trailing slash for the remote export (among other changes). The change happened here: > commit c7f404b40a3665d9f4e9a927cc5c1ee0479ed8f9 > Author: Al Viro <viro@xxxxxxxxxxxxxxxxxx> > Date: Wed Mar 16 06:59:40 2011 -0400 > > vfs: new superblock methods to override /proc/*/mount{s,info} > > a) ->show_devname(m, mnt) - what to put into devname columns in mounts, > mountinfo and mountstats > b) ->show_path(m, mnt) - what to put into relative path column in mountinfo > > Leaving those NULL gives old behaviour. NFS switched to using those. > > Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> > The "problematic" behavior is that NFS exports now have a trailing slash in /proc/self/mounts. This still seems to be the case in newer kernels, for example in Debian's 3.3.2-1~experimental.1. and HEAD in Linus Torvalds' master branch, presently commit: 02edf6abe01610a5fb379df442de3c837ad99467 I believe it is/was convention to leave a trailing slash off of the nfs export in /etc/fstab, e.g.: nfsserver:/srv/ubuntu-32 /mnt/ubuntu-32 nfs ro,nfsvers=3,soft,intr,tcp,nodev,noatime,nosuid,rsize=32768,wsize=32768 and I'd also expect the same in /proc/self/mounts Expected Result: I expect /proc/self/mounts to show (notice no trailing slash on the export): nfsserver:/srv/ubuntu-32 /mnt/ubuntu-32 nfs ro,nosuid,nodev,noatime,vers=3,rsize=32768,wsize=32768,namlen=255,soft,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=198.202.1.1,mountvers=3,mountport=41576,mountproto=tcp,local_lock=none,addr=198.202.1.1 0 0 Actual Result: But instead in /proc/self/mounts I get (notice the trailing slash): nfsserver:/srv/ubuntu-32/ /mnt/ubuntu-32 nfs ro,nosuid,nodev,noatime,vers=3,rsize=32768,wsize=32768,namlen=255,soft,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=198.202.1.1,mountvers=3,mountport=41576,mountproto=tcp,local_lock=none,addr=198.202.1.1 0 0 Rammifications: This simple change has a lot of implications because lots of things parse /etc/fstab and /proc/self/mounts, for example system configuration tools and mount.nfs and umount.nfs. If you use the former convention and try to umount an export on a newer kernel it will fail: user@hostname:/proc/self$ sudo umount.nfs nfsserver:/srv/ubuntu-32 umount.nfs: nfsserver:/srv/ubuntu-32: not found And if you run "sudo mount -va", mount will not recognize that the fstab mounts have already been mounted; mounting all mounts twice on the same mount point. This quickly gets messy. If there is a new convention to display the trailing slash, we need to update our tools to handle this change. If there is not a new convention, I'd argue this is a bug. So is this a new convention or not? What is the appropriate way for Debian to move forward? Thanks, Chris Hiestand -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
