On 02/26/15 at 11:23am, Dave Young wrote:
On 02/26/15 at 11:02am, Minfei Huang wrote:
> On 02/26/15 at 10:49am, Dave Young wrote:
> > Hi, Minfei
> >
> > > > > -bash-4.2# findmnt -v /var | tail -n 1 | awk '{print
$2}'
> > > > > /dev/mapper/atomicos-root
> > > >
> > > > There's no real dumping path for bind mount as we discussed in
previous
> > > > thread, right?
> > > >
> > >
> > > We can construct the real dump path for the bind mounted, using findmnt.
> > > As the above comment, we can identify the bind mount directory by using
> > > findmnt command.
> >
> > No, it did not answer my question, As Karel said for bind mount is same as
> > non-bind mount, see below the original source can be unmounted while the
> > later bind mount still exist:
> >
> > [dyoung@dhcp-xx-xx dyoung]# mount /dev/sda7 /mnt/sda7
> > [dyoung@dhcp-xx-xx dyoung]# ls /mnt/sda7
> > bin dev home lib64 media opt dyoung sbin sys usr
> > boot etc lib lost+found mnt proc run srv tmp var
> > [dyoung@dhcp-xx-xx dyoung]# ls /mnt/sda7/var
> > adm db games lock mail named rwho state www
> > cache empty lib log man run spool tmp yp
> > [dyoung@dhcp-xx-xx dyoung]# mount -o bind /mnt/sda7/var tmp
> > [dyoung@dhcp-xx-xx dyoung]# ls tmp
> > adm db games lock mail named rwho state www
> > cache empty lib log man run spool tmp yp
> > [dyoung@dhcp-xx-xx dyoung]# umount /mnt/sda7
> > [dyoung@dhcp-xx-xx dyoung]# ls tmp
> > adm db games lock mail named rwho state www
> > cache empty lib log man run spool tmp yp
> >
> Hi, Dave!
>
> Yes, but we can use the findmnt to recognize the directory is bind
> mounted or not, if the filesystem is not the btrfs.
>
> In your case, we can find the fact that real path of tmp directory is
> /dev/sda7[/var]. So we can dump core to the /dev/sda7[/var], if the
> target is tmp.
>
> The kdump's manner will be always correct, although the directory is
> bind mounted.
How did findmnt know this is a bindmnt, is it stable?
OTOH, we need consider more cases, such as non-root case I believe you tested
on atomic host. Have you tested normal bind mount test case, dump to root,
dump to non root, nfs, etc.?
Yes. I will test more cases to cover the generic testcase.
Thanks
Minfei
Thanks
Dave