panic: handle_written_inodeblock: Invalid link count 57368

I grabbed a spare USB 2 TB hard drive yesterday.  Put a GPT
scheme on the drive and then used newfs to create 1 large
UFS2 partition with softupdates and with journalling enabled.
I then some 150 GB of data to drive.  The drive in question is

ugen0.3: <Western Digital My Passport 0741> at usbus0
umass0 on uhub8
umass0: <MSC Bulk-Only Transport> on usbus0
umass0:  SCSI over Bulk-Only; quirks = 0x4000
umass0:9:0: Attached to scbus9
da0 at umass-sim0 bus 0 scbus9 target 0 lun 0
da0: <WD My Passport 0741 1022> Fixed Direct Access SPC-4 SCSI device
da0: Serial Number 575835314134334136333937
da0: 40.000MB/s transfers
da0: 1907697MB (3906963456 512 byte sectors)
da0: quirks=0x2<NO_6_BYTE>

I just got the indicated panic while trying to do ls
in a directory with 100+ files.  From the panic, I
have core.txt.7, info.7, and  vmcore.7.  info.7 contains

Dump header from device: /dev/ada0p3
  Architecture: amd64
  Architecture Version: 2
  Dump Length: 1150738432
  Blocksize: 512
  Dumptime: Fri Jun 16 11:47:07 2017
  Hostname: troutmask.apl.washington.edu
  Magic: FreeBSD Kernel Dump
  Version String: FreeBSD 12.0-CURRENT #0 r318546: Fri May 19 12:51:04 PDT 2017
    kargl_at_troutmask.apl.washington.edu:/data/obj/usr/src/sys/SPEW
  Panic String: handle_written_inodeblock: Invalid link count 57368 for inodedep 0xfffff800a56c4000
  Dump Parity: 2911432532
  Bounds: 7
  Dump Status: good

Leading portion of core.txt.7 is

Unread portion of the kernel message buffer:
panic: handle_written_inodeblock: Invalid link count 57368 for inodedep 0xfffff800a56c4000
cpuid = 3
time = 1497638827
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe022e2c40b0
vpanic() at vpanic+0x19c/frame 0xfffffe022e2c4130
panic() at panic+0x43/frame 0xfffffe022e2c4190
handle_written_inodeblock() at handle_written_inodeblock+0x7c9/frame 0xfffffe022e2c41e0
softdep_disk_write_complete() at softdep_disk_write_complete+0x1b4/frame 0xfffffe022e2c4240
bufdone_finish() at bufdone_finish+0x34/frame 0xfffffe022e2c42b0
bufdone() at bufdone+0x45/frame 0xfffffe022e2c42d0
g_io_deliver() at g_io_deliver+0x234/frame 0xfffffe022e2c4330
g_io_deliver() at g_io_deliver+0x234/frame 0xfffffe022e2c4390
g_disk_done() at g_disk_done+0x10d/frame 0xfffffe022e2c43e0
dadone() at dadone+0x1e21/frame 0xfffffe022e2c4960
xpt_done_process() at xpt_done_process+0x5d6/frame 0xfffffe022e2c49a0
xpt_done_td() at xpt_done_td+0x166/frame 0xfffffe022e2c49f0
fork_exit() at fork_exit+0x75/frame 0xfffffe022e2c4a30
fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe022e2c4a30
--- trap 0, rip = 0, rsp = 0, rbp = 0 ---
Uptime: 27d22h21m17s
(da0:umass-sim0:0:0:0): SYNCHRONIZE CACHE(10). CDB: 35 00 00 00 00 00 00 00 00 00 
(da0:umass-sim0:0:0:0): CAM status: Resource Unavailable
(da0:umass-sim0:0:0:0): Error 5, Retries exhausted
(da0:umass-sim0:0:0:0): Synchronize cache failed
Dumping 1097 out of 8142 MB:..2%..11%..21%..31%..41%..52%..62%..72%..81%..91%

Reading symbols from /boot/kernel/radeonkms.ko...Reading symbols from /usr/lib/debug//boot/kernel/radeonkms.ko.debug...done.
done.
Reading symbols from /boot/kernel/drm2.ko...Reading symbols from /usr/lib/debug//boot/kernel/drm2.ko.debug...done.
done.
Reading symbols from /boot/kernel/agp.ko...Reading symbols from /usr/lib/debug//boot/kernel/agp.ko.debug...done.
done.
Reading symbols from /boot/kernel/radeonkmsfw_CAICOS_pfp.ko...Reading symbols from /usr/lib/debug//boot/kernel/radeonkmsfw_CAICOS_pfp.ko.debug...done.
done.
Reading symbols from /boot/kernel/radeonkmsfw_CAICOS_me.ko...Reading symbols from /usr/lib/debug//boot/kernel/radeonkmsfw_CAICOS_me.ko.debug...done.
done.
Reading symbols from /boot/kernel/radeonkmsfw_BTC_rlc.ko...Reading symbols from /usr/lib/debug//boot/kernel/radeonkmsfw_BTC_rlc.ko.debug...done.
done.
Reading symbols from /boot/kernel/radeonkmsfw_CAICOS_mc.ko...Reading symbols from /usr/lib/debug//boot/kernel/radeonkmsfw_CAICOS_mc.ko.debug...done.
done.
__curthread () at ./machine/pcpu.h:232
232		__asm("movq %%gs:%1,%0" : "=r" (td)
(kgdb) #0  __curthread () at ./machine/pcpu.h:232
#1  doadump (textdump=1) at /usr/src/sys/kern/kern_shutdown.c:318
#2  0xffffffff8058649b in kern_reboot (howto=260)
    at /usr/src/sys/kern/kern_shutdown.c:386
#3  0xffffffff80586916 in vpanic (fmt=<optimized out>, ap=0xfffffe022e2c4170)
    at /usr/src/sys/kern/kern_shutdown.c:779
#4  0xffffffff80586733 in panic (fmt=<unavailable>)
    at /usr/src/sys/kern/kern_shutdown.c:710
#5  0xffffffff8079c1b9 in handle_written_inodeblock (
    inodedep=0xfffff800a56c4000, bp=0xfffffe01f01b7a58, flags=<optimized out>)
    at /usr/src/sys/ufs/ffs/ffs_softdep.c:11535
#6  0xffffffff80782514 in softdep_disk_write_complete (bp=0xfffffe01f01b7a58)
    at /usr/src/sys/ufs/ffs/ffs_softdep.c:11043
#7  0xffffffff8061d2b4 in buf_complete (bp=0xfffffe01f01b7a58)
    at /usr/src/sys/sys/buf.h:422
#8  bufdone_finish (bp=0xfffffe01f01b7a58) at /usr/src/sys/kern/vfs_bio.c:4045
#9  0xffffffff8061d1b5 in bufdone (bp=0xfffffe01f01b7a58)
    at /usr/src/sys/kern/vfs_bio.c:4033
#10 0xffffffff8050df14 in g_io_deliver (bp=0xfffff80115d71bc0, 
    error=<optimized out>) at /usr/src/sys/geom/geom_io.c:738
#11 0xffffffff8050df14 in g_io_deliver (bp=0xfffff801fd3b32f0, 
    error=<optimized out>) at /usr/src/sys/geom/geom_io.c:738
#12 0xffffffff8050b77d in g_disk_done (bp=0xfffff8007613c2f0)
    at /usr/src/sys/geom/geom_disk.c:256
#13 0xffffffff802ef1b1 in dadone (periph=<optimized out>, 
    done_ccb=0xfffff80068599800) at /usr/src/sys/cam/scsi/scsi_da.c:4216
#14 0xffffffff80292936 in xpt_done_process (ccb_h=0xfffff80068599800)
    at /usr/src/sys/cam/cam_xpt.c:5453
#15 0xffffffff80294ab6 in xpt_done_td (
    arg=0xffffffff80bf9300 <cam_doneqs+256>)
    at /usr/src/sys/cam/cam_xpt.c:5480
#16 0xffffffff80553ff5 in fork_exit (
    callout=0xffffffff80294950 <xpt_done_td>, 
    arg=0xffffffff80bf9300 <cam_doneqs+256>, frame=0xfffffe022e2c4a40)
    at /usr/src/sys/kern/kern_fork.c:1038
#17 <signal handler called>

core.txt.7 and vmcore.7 can be made available for the asking.



-- 
Steve
20170425 https://www.youtube.com/watch?v=VWUpyCsUKR4
20161221 https://www.youtube.com/watch?v=IbCHE-hONow