current transaction too big to flush

[Dima Veselov <kab00m%lich.phys.spbu.ru@localhost>]

Hello,

Maybe I need to create PR, but here might be a
person already met the situation of kernel panic
on big file operation. When I try to delete several
files (from 1 to 8 Gb at once) from net/transmission
interface I get kernel panic like this:

panic: wapbl_flush: current transaction too big to flush
cpu0: Begin traceback...
vpanic() at netbsd:vpanic+0x15d
snprintf() at netbsd:snprintf
wapbl_stop() at netbsd:wapbl_stop
wapbl_begin() at netbsd:wapbl_begin+0x5b
ufs_inactive() at netbsd:ufs_inactive+0x13a
VOP_INACTIVE() at netbsd:VOP_INACTIVE+0x4c
vrelel() at netbsd:vrelel+0x168
ufs_remove() at netbsd:ufs_remove+0xab
VOP_REMOVE() at netbsd:VOP_REMOVE+0x50
do_sys_unlinkat.isra.5() at netbsd:do_sys_unlinkat.isra.5+0x1eb
syscall() at netbsd:syscall+0x1ec
--- syscall (number 10) ---
7887406fb53a:
cpu0: End traceback...

I also have question about dumping: kernel can't
do dump on panic:

dumping to dev 168,2 (offset=4278362, size=515454):
dump device bad

Why it is bad if it work as a swap normally?

[root@ssd ~]$ swapctl  -l
Device      512-blocks     Used    Avail Capacity  Priority
/dev/dk2       8401995        0  8401995     0%    0
[root@ssd ~]$ ls -la /dev/dk2
brw-r-----  1 root  operator  168, 2 Apr 19  2018 /dev/dk2