Re: [REGRESSION] smb: client: batch SRV_COPYCHUNK entries to cut round trips - 6.12.y EIO above 12 MiB with SMB3 encryption

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Fri, Oct 16, 2026 at 11:08:20AM -0300, Paulo Alcantara wrote:
> Paul Aurich <paul@darkrain42.org> writes:
> 
> > On 2026-10-15 16:54:29 -0300, Paulo Alcantara wrote:
> >>Thanks for the report.
> >>
> >>Paul Aurich <paul@darkrain42.org> writes:
> >>
> >>> In stable 6.12.y releases, a copy_file_range request exceeding 12 MiB on an
> >>> encrypted SMB3 mount fails with EIO and a WARN_ON_ONCE() splat in
> >>> SMB2_ioctl_init:
> >>>
> >>>      # cp /mnt/otters/13mib.bin /mnt/otters/output.bin
> >>>      cp: error copying '/mnt/otters/13mib.bin' to '/mnt/otters/output.bin':
> >>>      Input/output error
> >>>
> >>> Works in 6.12.110.  Fails in 6.12.111 through 6.12.113 (latest).  Via
> >>> bisection, introduced by 8d103b285359 ("smb: client: batch SRV_COPYCHUNK
> >>> entries to cut round trips").
> >>
> >>Does it work if you backport the other 3 missing commits?
> >
> > Yes.  With v6.12.113 + bc925c1216f0 + 9f544d26b15b + 90f7c100d2dd, 'cp' and 
> > the Python reproducer work.  (Tested with both a 13 MiB file and a 250 MiB 
> > file)
> 
> Thanks for testing it!
> 
> Greg,
> 
> Could you please backport the following to v6.12.y
> 
> 	bc925c1216f0 ("smb: client: improve compound padding in encryption")
> 	9f544d26b15b ("smb: client: get rid of bounds check in SMB2_ioctl_init()")
> 	90f7c100d2dd ("smb: client: fix compound alignment with encryption")

Now queued up, thanks.

greg k-h