releases/4.14.60/f2fs-fix-deadlock-in-shutdown-ioctl.patch

   1 From foo@baz Sat Jul 28 10:25:26 CEST 2018
   2 From: Sahitya Tummala <stummala@codeaurora.org>
   3 Date: Fri, 18 May 2018 11:51:52 +0530
   4 Subject: f2fs: Fix deadlock in shutdown ioctl
   5
   6 From: Sahitya Tummala <stummala@codeaurora.org>
   7
   8 [ Upstream commit 60b2b4ee2bc01dd052f99fa9d65da2232102ef8e ]
   9
  10 f2fs_ioc_shutdown() ioctl gets stuck in the below path
  11 when issued with F2FS_GOING_DOWN_FULLSYNC option.
  12
  13 __switch_to+0x90/0xc4
  14 percpu_down_write+0x8c/0xc0
  15 freeze_super+0xec/0x1e4
  16 freeze_bdev+0xc4/0xcc
  17 f2fs_ioctl+0xc0c/0x1ce0
  18 f2fs_compat_ioctl+0x98/0x1f0
  19
  20 Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
  21 Reviewed-by: Chao Yu <yuchao0@huawei.com>
  22 Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
  23 Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
  24 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  25 ---
  26  fs/f2fs/file.c |   11 +++++++----
  27  1 file changed, 7 insertions(+), 4 deletions(-)
  28
  29 --- a/fs/f2fs/file.c
  30 +++ b/fs/f2fs/file.c
  31 @@ -1808,9 +1808,11 @@ static int f2fs_ioc_shutdown(struct file
  32         if (get_user(in, (__u32 __user *)arg))
  33                 return -EFAULT;
  34
  35 -       ret = mnt_want_write_file(filp);
  36 -       if (ret)
  37 -               return ret;
  38 +       if (in != F2FS_GOING_DOWN_FULLSYNC) {
  39 +               ret = mnt_want_write_file(filp);
  40 +               if (ret)
  41 +                       return ret;
  42 +       }
  43
  44         switch (in) {
  45         case F2FS_GOING_DOWN_FULLSYNC:
  46 @@ -1838,7 +1840,8 @@ static int f2fs_ioc_shutdown(struct file
  47         }
  48         f2fs_update_time(sbi, REQ_TIME);
  49  out:
  50 -       mnt_drop_write_file(filp);
  51 +       if (in != F2FS_GOING_DOWN_FULLSYNC)
  52 +               mnt_drop_write_file(filp);
  53         return ret;
  54  }
  55