kern/139062: panic on shutdown after busy snapshot removal

[Edward Tomasz Napierala]

>Number:         139062
>Category:       kern
>Synopsis:       panic on shutdown after busy snapshot removal
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Sep 22 14:10:02 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator:     Edward Tomasz Napierala
>Release:        9.0
>Organization:
>Environment:
>Description:
Reboot after removal of busy snapshot leads to panic with backtrace looking like this:

zfsctl_snapshot_inactive()
vinactive()
vgonel()
vflush()
zfs_umount()
dounmount()
vfs_unmountall()
boot()
reboot()
syscall()
Xfast_syscall()

>How-To-Repeat:
cd /usr/obj/.zfs/snapshot/blah/
ls -al
zfs destroy tank/obj at blah
reboot

>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: