Re: Need advice about do we need this if condition
From: Steve French
Date: Wed Apr 17 2019 - 09:32:28 EST
On Wed, Apr 17, 2019 at 2:59 AM Valdis KlÄtnieks
> On Wed, 17 Apr 2019 08:25:22 +0300
> (Adding Al Viro and the linux-fsdevel lists, as at the very least, the manpage
> for the syscall needs some clarification...)
> > hello I am trying to fix https://bugzilla.kernel.org/show_bug.cgi?id=202935
> So - convince us that it's in fact a "bug" and not a restriction.
> > I found cause
> > https://github.com/torvalds/linux/blob/master/fs/cifs/cifsfs.c#L1076 not
> > sure is it correct to remove such condition ?
> Does the CIFS protocol support copying from a file to another location in the
> same file? Was it intended to work on *any* filesystem?
Looks like it should be allowed on the same file as long as the source
and target file ranges do not overlap
section 18.104.22.168 and 2.3.8
Server returns STATUS_NOT_SUPPORTED if "The source and target
destination ranges overlap on the same file."
and line 112 and following of smb2_ioctl_filesys.c in Samba code
> (For that matter, the manpage for the syscall is unclear on whether having both
> file descriptors open on the same file is OK or not - for bonus ambiguity
> points, there's exactly zero discussion of what happens if source and
> destination overlap destructively).