On Fri, Nov 18, 2011 at 12:44:51AM -0300, Gerardo Exequiel Pozzi wrote: > On 11/18/2011 12:22 AM, Dave Reisner wrote: > >On Fri, Nov 18, 2011 at 12:12:28AM -0300, Gerardo Exequiel Pozzi wrote: > >>On 11/18/2011 12:03 AM, Dave Reisner wrote: > >>>No, that absolutely _will_ work. Binding arbitrary directories is > >>>totally kosher, and I do it fairly frequently. You can even bind mount > >>>files, i.e. > >>> > >>> echo blah> foo > >>> touch bar > >>> mount -B foo bar > >>> > >>>When you 'cat bar' it will have the same contents as 'foo'. > >>I know, but again, rootfs is the *HEAD* of vfsmount. > >> > >>[ramfs /]# mkdir a b > >>[ramfs /]# mount --bind a b > >>mount: mounting a on b failed: Invalid argument > >>[ramfs /]# mkdir coco > >>[ramfs /]# mount -t tmpfs coco coco > >>[ramfs /]# cd coco/ > >>[ramfs /coco]# mkdir a b > >>[ramfs /coco]# mount --bind a b > >>[ramfs /coco]# > >> > >Ahh, there's the lightbulb. More specifically, directories in the root > >can't be bind mounted. Seems the inverse doesn't hold true. > Not exactly. you are mixing things. > /run is on another filesystem > > When I say rootfs I talk about of a type of filesystem. > > Do not confuse, rootfs (an special tmpfs/ramfs is the head, it does > not have a name, you can not reference, this implies you can not > unmount, bind, move and pivot). > >
d'oh, right. poor place to test my assumptions. time for sleep, dave. yeah, it all makes sense. > > > >[ramfs /]# mkdir /a > >[ramfs /]# mount -B /run/initramfs/ /a > works because you are binding a tmpfs. > repeat the same with /somedir/lalala, the result is exactly as below.... > >[ramfs /]# umount /a > > >[ramfs /]# mount -B /a /run/initramfs/ > >mount: wrong fs type, bad option, bad superblock on /a, > > missing codepage or helper program, or other error > > In some cases useful info is found in syslog - try > > dmesg | tail or so > does not works because you are trying to reference an "unnamed" > mountpoint. There is no "source" for such fs. > > > > > >(oh the joys of the soul-less vacuum that is early userspace) > > > >d > > haha :P > > -- > Gerardo Exequiel Pozzi > \cos^2\alpha + \sin^2\alpha = 1 >
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