On Thu, Jun 11, 2020 at 09:23:23AM +0900, Daeho Jeong wrote: > Yes, I saw the implementation in vfs_write(). > But if we use mnt_want_write_file() here, it'll call mnt_clone_write() > internally if the file is already open in write mode. > Don't you think the below thing is needed? We can increase the counter > each of them, open and ioctl, like other filesystems such as ext4. > > int mnt_clone_write(struct vfsmount *mnt) > { > /* superblock may be r/o */ > if (__mnt_is_readonly(mnt)) > return -EROFS; > preempt_disable(); > mnt_inc_writers(real_mount(mnt)); > preempt_enable(); > return 0; > }
No, this seems to be left over from when mnt_want_write_file() was paired with mnt_drop_write() instead of mnt_drop_write_file(). I sent a patch to remove it: https://lkml.kernel.org/r/20200611014945.237210-1-ebigg...@kernel.org - Eric