Re: [PATCH] cifs: fix pcchunk length type in smb2_copychunk_range

[Pawel Witek <pawel.ireneusz.witek@gmail.com>]

I've tried to copy a 5 GB file which resulted in -EINVAL (same for larger
files). After wiresharking the protocol I've observed that one packet
requests ioctl with 'Transfer Length: 0', to which the server responded
with an error. Some investigation showed, that this happens when
len=4294967296.

On 5/5/23 18:47, Steve French wrote:
> since pcchunk->Length is a 32 bit field doing cpu_to_le64 seems wrong.
> 
> Perhaps one option is to split this into two lines do the minimum(u64, len, tcon->max_bytes_chunk) on one line and the cpu_to_le32 of the result on the next
> 
> What is "len" in the example you see failing?
> 
> On Fri, May 5, 2023 at 10:15 AM Pawel Witek <pawel.ireneusz.witek@gmail.com <mailto:pawel.ireneusz.witek@gmail.com>> wrote:
> 
>     Change type of pcchunk->Length from u32 to u64 to match
>     smb2_copychunk_range arguments type. Fixes the problem where performing
>     server-side copy with CIFS_IOC_COPYCHUNK_FILE ioctl resulted in incomplete
>     copy of large files while returning -EINVAL.
> 
>     Signed-off-by: Pawel Witek <pawel.ireneusz.witek@gmail.com <mailto:pawel.ireneusz.witek@gmail.com>>
>     ---
>      fs/cifs/smb2ops.c | 2 +-
>      1 file changed, 1 insertion(+), 1 deletion(-)
> 
>     diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
>     index a81758225fcd..35c7c35882c9 100644
>     --- a/fs/cifs/smb2ops.c
>     +++ b/fs/cifs/smb2ops.c
>     @@ -1682,7 +1682,7 @@ smb2_copychunk_range(const unsigned int xid,
>                     pcchunk->SourceOffset = cpu_to_le64(src_off);
>                     pcchunk->TargetOffset = cpu_to_le64(dest_off);
>                     pcchunk->Length =
>     -                       cpu_to_le32(min_t(u32, len, tcon->max_bytes_chunk));
>     +                       cpu_to_le64(min_t(u64, len, tcon->max_bytes_chunk));
> 
>                     /* Request server copy to target from src identified by key */
>                     kfree(retbuf);
>     -- 
>     2.40.1
> 
> 
> 
> 
> -- 
> Thanks,
> 
> Steve