ffs_truncate3 panics

[Rick Macklem]

Konstantin Belousov wrote:
>On Thu, Aug 09, 2018 at 08:38:50PM +0000, Rick Macklem wrote:
>> I did notice that my code locks the vnode first and then calls vn_start_write()
>>  for the vn_extattr_set() calls, whereas the syscall code locks the vnode after the vn_start_write() call.
>>
>> Does that matter?
>
>Yes, it matter.  It would cause deadlocks when corresponding filesystem
>is suspended in parallel with NFSD activities.  vn_start_write() is a lock,
>and the correct lock order is vn_start_write()->vnode lock.
Ok, thanks, I'll work on a patch to fix this LOR.

rick