On Fri, Jul 28, 2017 at 12:13:52PM -0700, Matthew Wilcox wrote:
> On Sat, Jul 29, 2017 at 02:29:58AM +0800, weiping zhang wrote:
> > Some filesystems not support O_DIRECT, when user open with O_DIRECT ,
> > an errno -EINVAL return to userspace by open_check_o_direct, but the
> > file has been created, it's a strange thing. Add a checking for that
> > can avoid creating file if fs not support O_DIRECT.
>
> > if (error)
> > goto out_dput;
> > + /* if fs not support direct io, delete this inode */
> > + if (unlikely(open_flag & O_DIRECT) &&
> > + !(dentry->d_inode->i_mapping &&
> > + dentry->d_inode->i_mapping->a_ops &&
> > + dentry->d_inode->i_mapping->a_ops->direct_IO) &&
> > + dir_inode->i_op->unlink) {
> > + error = dir_inode->i_op->unlink(dir_inode, dentry);
> > + if (error == 0)
> > + error = -EINVAL;
> > + goto out_dput;
>
> Surely it's better to change the prototype of ->create to take open_flag
> (like atomic_open does) and then have the filesystem check for O_DIRECT?
> This solution seems quite inelegant to me.
thanks your better suggestion, the only concern for me is Viro said:
>>Not to mention the modules, or filesystems where that depends upon e.g. mount flags...
So I try to find a common way to do that, the positve: only modify 1
file, no affect any specific filysystems, the negtive: this patch seems
ugly. if we add/change prototype of ->create every fs will be patched.
And if you are in favor of me changing prototype of ->create ,I will
send a new patch.
