Re: Mounting cd9660 multiple times gives EBUSY [Was: unionfs a little improvement]
On Wed, Aug 18, 2010 at 12:48:53PM +0200, Ed Schouten wrote: Hi Daichi, I think Keith Packard of Xorg once wrote a commit message along the lines of 5000 lines of code removed, feature added This seems to be similar, albeit on a smaller scale. ;-) Apart from this issue with unionfs, I am also experiencing another issue, where for some reason I cannot perform a second mount of the CD right after booting the system. Basically, my WIP FreeBSD boot CD does the following (but written in C): mount -t cd9660 /dev/iso9660/freebsd /mnt mount -t tmpfs none /tmp mount -t unionfs /tmp /mnt mount -t devfs none /mnt/dev chroot /mnt /sbin/init The first step fails with EBUSY. I use the following hack to get it working, but I don't think it's the proper way to solve it: What you are trying to do here is to mount /dev/iso9660/freebsd for the second time? This is not supported. The check is there to prevent doing this, as it will panic on you when you try to unmount first mount (not really a problem in your case, as the first mount is /, so you probably don't want to unmount it, but it is a problem in general). You should be able to reproduce the panic with your patch applied by doing the following: # mount -t cd9660 /dev/iso9660/freebsd /mnt0 # mount -t cd9660 /dev/iso9660/freebsd /mnt1 # umount /mnt0 -- Pawel Jakub Dawidek http://www.wheelsystems.com p...@freebsd.org http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am! pgp88NLmz310d.pgp Description: PGP signature
Mounting cd9660 multiple times gives EBUSY [Was: unionfs a little improvement]
Hi Daichi, I think Keith Packard of Xorg once wrote a commit message along the lines of 5000 lines of code removed, feature added This seems to be similar, albeit on a smaller scale. ;-) Apart from this issue with unionfs, I am also experiencing another issue, where for some reason I cannot perform a second mount of the CD right after booting the system. Basically, my WIP FreeBSD boot CD does the following (but written in C): mount -t cd9660 /dev/iso9660/freebsd /mnt mount -t tmpfs none /tmp mount -t unionfs /tmp /mnt mount -t devfs none /mnt/dev chroot /mnt /sbin/init The first step fails with EBUSY. I use the following hack to get it working, but I don't think it's the proper way to solve it: %%% Index: sys/geom/geom_vfs.c === --- sys/geom/geom_vfs.c (revision 211093) +++ sys/geom/geom_vfs.c (working copy) @@ -162,8 +162,10 @@ *cpp = NULL; bo = vp-v_bufobj; +#if 0 if (bo-bo_private != vp) return (EBUSY); +#endif pp = g_dev_getprovider(vp-v_rdev); if (pp == NULL) %%% I am really not that familiar with GEOM/VFS to understand the impact of this change. What does it actually mean if bo-bo_private != vp? -- Ed Schouten e...@80386.nl WWW: http://80386.nl/ pgpDtQb4iDzU5.pgp Description: PGP signature
Re: Mounting cd9660 multiple times gives EBUSY [Was: unionfs a little improvement]
* Pawel Jakub Dawidek p...@freebsd.org wrote: What you are trying to do here is to mount /dev/iso9660/freebsd for the second time? This is not supported. The check is there to prevent doing this, as it will panic on you when you try to unmount first mount (not really a problem in your case, as the first mount is /, so you probably don't want to unmount it, but it is a problem in general). You should be able to reproduce the panic with your patch applied by doing the following: # mount -t cd9660 /dev/iso9660/freebsd /mnt0 # mount -t cd9660 /dev/iso9660/freebsd /mnt1 # umount /mnt0 Ah, I see. Well, I changed my setup to use an md root now. Works quite nicely. Screenshot: http://80386.nl/pub/livecd.png Thanks for the explanation! -- Ed Schouten e...@80386.nl WWW: http://80386.nl/ pgps9FfC06S09.pgp Description: PGP signature
