• Ilya Dryomov's avatar
    rbd: don't return 0 on unmap if RBD_DEV_FLAG_REMOVING is set · 85f5a4d6
    Ilya Dryomov authored
    There is a window between when RBD_DEV_FLAG_REMOVING is set and when
    the device is removed from rbd_dev_list.  During this window, we set
    "already" and return 0.
    
    Returning 0 from write(2) can confuse userspace tools because
    0 indicates that nothing was written.  In particular, "rbd unmap"
    will retry the write multiple times a second:
    
      10:28:05.463299 write(4, "0", 1)        = 0
      10:28:05.463509 write(4, "0", 1)        = 0
      10:28:05.463720 write(4, "0", 1)        = 0
      10:28:05.463942 write(4, "0", 1)        = 0
      10:28:05.464155 write(4, "0", 1)        = 0
    
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
    Tested-by: default avatarDongsheng Yang <dongsheng.yang@easystack.cn>
    85f5a4d6
rbd.c 155 KB