On Wed, Apr 17, 2019 at 2:59 AM Valdis Klētnieks <valdis.kletnieks@xxxxxx> wrote: > > 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 See https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-fscc/1ee611b7-43f0-468c-8a9d-28f04cdc3376 section 2.3.7.2 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 https://git.samba.org/?p=samba.git;a=blob;f=source3/smbd/smb2_ioctl_filesys.c;h=8a9c8c64ec9ddbca4623251555f4792d76aa6e44;hb=refs/heads/master#l112 > (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). > -- Thanks, Steve
