System hangs when getting a snapshot of root LV

Issue

• An lvcreate command that is getting a snapshot of root LV is blocked in D state, and the system hangs.

  crash> bt 32570
  PID: 32570    TASK: ffff89ce70809080  CPU: 0    COMMAND: "lvcreate"
   #0 [ffff89cc81a4b7f0] __schedule at ffffffffaebb78d8
   #1 [ffff89cc81a4b858] schedule at ffffffffaebb7ca9
   #2 [ffff89cc81a4b868] schedule_timeout at ffffffffaebb5831
   #3 [ffff89cc81a4b910] wait_for_completion at ffffffffaebb805d
   #4 [ffff89cc81a4b970] xfs_buf_iowait at ffffffffc05419f7 [xfs]
   #5 [ffff89cc81a4b998] __xfs_buf_submit at ffffffffc0543320 [xfs]
   #6 [ffff89cc81a4b9c8] _xfs_buf_read at ffffffffc0543465 [xfs]
   #7 [ffff89cc81a4b9d8] xfs_buf_read_map at ffffffffc0543569 [xfs]
   #8 [ffff89cc81a4ba20] xfs_trans_read_buf_map at ffffffffc05752a9 [xfs]
   #9 [ffff89cc81a4ba60] xfs_da_read_buf at ffffffffc051ffab [xfs]
  #10 [ffff89cc81a4bae0] xfs_dir3_block_read at ffffffffc052508d [xfs]
  #11 [ffff89cc81a4bb10] xfs_dir2_block_lookup_int at ffffffffc052510b [xfs]
  #12 [ffff89cc81a4bb88] xfs_dir2_block_lookup at ffffffffc0525bc7 [xfs]
  #13 [ffff89cc81a4bbc0] xfs_dir_lookup at ffffffffc05245a4 [xfs]
  #14 [ffff89cc81a4bc10] xfs_lookup at ffffffffc0556749 [xfs]
  #15 [ffff89cc81a4bc58] xfs_vn_lookup at ffffffffc0553458 [xfs]
  #16 [ffff89cc81a4bc90] lookup_real at ffffffffae666963
  #17 [ffff89cc81a4bcb0] __lookup_hash at ffffffffae6673b2
  #18 [ffff89cc81a4bce0] lookup_slow at ffffffffaebae6fc
  #19 [ffff89cc81a4bd18] path_lookupat at ffffffffae66b06e
  #20 [ffff89cc81a4bdb0] filename_lookup at ffffffffae66b0cb
  #21 [ffff89cc81a4bde8] user_path_at_empty at ffffffffae66ee47
  #22 [ffff89cc81a4bec0] user_path_at at ffffffffae66eeb1
  #23 [ffff89cc81a4bed0] sys_faccessat at ffffffffae659c72
  #24 [ffff89cc81a4bf40] sys_access at ffffffffae659e08
  #25 [ffff89cc81a4bf50] system_call_fastpath at ffffffffaebc539a
      RIP: 00007f11dd63b4e0  RSP: 00007ffc381080a8  RFLAGS: 00010246
      RAX: 0000000000000015  RBX: 00007f11de012598  RCX: 0000000000000043
      RDX: 000000000000000a  RSI: 0000000000000000  RDI: 00007f11dd733dc0
      RBP: 0000000000000000   R8: 00007f11dea8a998   R9: 00007f11dea8a998
      R10: 00007ffc38107660  R11: 0000000000000246  R12: 000055886b6dd040
      R13: 0000000000004000  R14: 000055886b6d89c0  R15: 0000000000000000
      ORIG_RAX: 0000000000000015  CS: 0033  SS: 002b