Re: Mount options may be silently discarded

2020-09-28 Thread Al Viro
On Mon, Sep 28, 2020 at 09:00:54PM +0300, Dmitry Kasatkin wrote: > But why "we" should allow "discarding" failed part instead of failing > with EFAULT as a whole? Because there might very well be absolutely legitimate users of mount(2) passing it something smaller than 4Kb immediately followed

Re: Mount options may be silently discarded

2020-09-28 Thread Dmitry Kasatkin
On Mon, Sep 28, 2020 at 5:36 PM David Laight wrote: > > From: Dmitry Kasatkin > > Sent: 28 September 2020 15:03 > > > > "copy_mount_options" function came to my eyes. > > It splits copy into 2 pieces - over page boundaries. > > I wonder what is the real reason for doing this? > > Original comment

RE: Mount options may be silently discarded

2020-09-28 Thread David Laight
From: Dmitry Kasatkin > Sent: 28 September 2020 15:03 > > "copy_mount_options" function came to my eyes. > It splits copy into 2 pieces - over page boundaries. > I wonder what is the real reason for doing this? > Original comment was that we need exact bytes and some user memcpy > functions do

Mount options may be silently discarded

2020-09-28 Thread Dmitry Kasatkin
Hi, "copy_mount_options" function came to my eyes. It splits copy into 2 pieces - over page boundaries. I wonder what is the real reason for doing this? Original comment was that we need exact bytes and some user memcpy functions do not return correct number on page fault. But how would all