login: vn0: MBR magic not found; assume a COMPATIBILITY_SLICE (s0)
vn0: MBR magic not found; assume a COMPATIBILITY_SLICE (s0)
vn0: MBR magic not found; assume a COMPATIBILITY_SLICE (s0)
panic: ext2_blkfree: freeing free block 499, fs=/mnt/df3175
cpuid = 0
Trace beginning at frame 0xfffff80118297528
ext2_blkfree() at ext2_blkfree+0x28d 0xffffffff82601cbd 
ext2_blkfree() at ext2_blkfree+0x28d 0xffffffff82601cbd 
ext2_truncate() at ext2_truncate+0x3aa 0xffffffff82607bca 
ext2_setattr() at ext2_setattr+0x21a 0xffffffff8260f63a 
vop_setattr() at vop_setattr+0x54 0xffffffff8070a3c4 
kern_ftruncate() at kern_ftruncate+0x190 0xffffffff80705e60 
Debugger("panic")

CPU0 stopping CPUs: 0x0000003e
 stopped
Stopped at      Debugger+0x7c:  movb    $0,0xbdaf09(%rip)
db>