• Junichi Nomura's avatar
    dm: fix ioctl retry termination with signal · a6248845
    Junichi Nomura authored
    commit 5bbbfdf6 upstream.
    
    dm-mpath retries ioctl, when no path is readily available and the device
    is configured to queue I/O in such a case. If you want to stop the retry
    before multipathd decides to turn off queueing mode, you could send
    signal for the process to exit from the loop.
    
    However the check of fatal signal has not carried along when commit
    6c182cd8 ("dm mpath: fix ioctl deadlock when no paths") moved the
    loop from dm-mpath to dm core. As a result, we can't terminate such
    a process in the retry loop.
    
    Easy reproducer of the situation is:
    
      # dmsetup create mp --table '0 1024 multipath 0 0 0 0'
      # dmsetup message mp 0 'queue_if_no_path'
      # sg_inq /dev/mapper/mp
    
    then you should be able to terminate sg_inq by pressing Ctrl+C.
    
    Fixes: 6c182cd8 ("dm mpath: fix ioctl deadlock when no paths")
    Signed-off-by: default avatarJun'ichi Nomura <j-nomura@ce.jp.nec.com>
    Cc: Hannes Reinecke <hare@suse.de>
    Cc: Mikulas Patocka <mpatocka@redhat.com>
    Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
    [ luis: backported to 3.16: adjusted context ]
    Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
    a6248845
dm-mpath.c 39.8 KB