Hi guys,
On shutdown we unmount/remount most filesystems. However, we make exception fro the "api" filesystems as they might still be useful and they are anyway not backed by a block device.
The problem is that umount does not easily let us make exception based on mountpoints, but we have to use mounttype instead. For /sys and /proc this is ok, but /dev might be tmpfs, so we have until now avoided unmounting any tmpfs filesystems.
This might be a problem if a tmpfs system is a submount of a blockdevice, as this will block the unmounting of the parent device.
The attached patch (originally by Gerardo) fixes this problem when /dev is mounted as devtmpfs and keeps the old behavior if /dev is tmpfs.
I made some adjustments, as noted in the commit message (Gerardo, please let me know if this looks ok with you).
If someone knows of any reason not to unmount tmpfs or ramfs on shutdown, please speak up. I"m happy you ask this. Because your mail subject remember me an old story about win98 (i guess), which have a big improvment from 95, by don't unloading some driver at shutdown because it was unecessary. This "improvment" speed up the shutdown. So the question, was, is
On Sat, Apr 23, 2011 at 4:32 PM, Tom Gundersen <teg@jklm.no> wrote: there a reason to unmount ramfs at shutdown? I understand the unmount chaining issue, but i don't see which case is problematic, do you have a ticket # ? 2 small points about your patch: - You should use /bin/grep and not grep, like everywhere else. - A comment before the if then else to explain why we do this will be cool. -- Sébastien Luttringer www.seblu.net