[v2 PATCH] CIFS: Fix incorrect max RFC1002 write size value

[v2 PATCH] CIFS: Fix incorrect max RFC1002 write size value

[Pavel Shilovsky]

..the length field has only 17 bits.

Signed-off-by: Pavel Shilovsky <piastry-7qunaywFIewox3rIn2DAYQ@public.gmane.org>
---
 fs/cifs/connect.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 633c246..1a645ee 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2807,10 +2807,10 @@ void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
 
 /*
  * When the server doesn't allow large posix writes, only allow a wsize of
- * 128k minus the size of the WRITE_AND_X header. That allows for a write up
+ * 2^17-1 minus the size of the WRITE_AND_X header. That allows for a write up
  * to the maximum size described by RFC1002.
  */
-#define CIFS_MAX_RFC1002_WSIZE (128 * 1024 - sizeof(WRITE_REQ) + 4)
+#define CIFS_MAX_RFC1002_WSIZE ((1<<17) - 1 - sizeof(WRITE_REQ) + 4)
 
 /*
  * The default wsize is 1M. find_get_pages seems to return a maximum of 256
-- 
1.7.1

Re: [v2 PATCH] CIFS: Fix incorrect max RFC1002 write size value

[Jeff Layton]

On Fri,  7 Oct 2011 23:27:31 +0400
Pavel Shilovsky <piastry-7qunaywFIewox3rIn2DAYQ@public.gmane.org> wrote:

> ..the length field has only 17 bits.
> 
> Signed-off-by: Pavel Shilovsky <piastry-7qunaywFIewox3rIn2DAYQ@public.gmane.org>
> ---
>  fs/cifs/connect.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index 633c246..1a645ee 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -2807,10 +2807,10 @@ void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
>  
>  /*
>   * When the server doesn't allow large posix writes, only allow a wsize of
> - * 128k minus the size of the WRITE_AND_X header. That allows for a write up
> + * 2^17-1 minus the size of the WRITE_AND_X header. That allows for a write up
>   * to the maximum size described by RFC1002.
>   */
> -#define CIFS_MAX_RFC1002_WSIZE (128 * 1024 - sizeof(WRITE_REQ) + 4)
> +#define CIFS_MAX_RFC1002_WSIZE ((1<<17) - 1 - sizeof(WRITE_REQ) + 4)
>  
>  /*
>   * The default wsize is 1M. find_get_pages seems to return a maximum of 256

Looks fine...

If we're going to do this though, should we also consider getting rid
of the bogus pad in the WRITE_REQ header? It's preferable to make the
wsize as large as we can get away with...

Acked-by: Jeff Layton <jlayton-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>

Re: [v2 PATCH] CIFS: Fix incorrect max RFC1002 write size value

[Pavel Shilovsky]

2011/10/9 Jeff Layton <jlayton-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>:
> On Fri,  7 Oct 2011 23:27:31 +0400
> Pavel Shilovsky <piastry-7qunaywFIewox3rIn2DAYQ@public.gmane.org> wrote:
>
>> ..the length field has only 17 bits.
>>
>> Signed-off-by: Pavel Shilovsky <piastry-7qunaywFIewox3rIn2DAYQ@public.gmane.org>
>> ---
>>  fs/cifs/connect.c |    4 ++--
>>  1 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
>> index 633c246..1a645ee 100644
>> --- a/fs/cifs/connect.c
>> +++ b/fs/cifs/connect.c
>> @@ -2807,10 +2807,10 @@ void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
>>
>>  /*
>>   * When the server doesn't allow large posix writes, only allow a wsize of
>> - * 128k minus the size of the WRITE_AND_X header. That allows for a write up
>> + * 2^17-1 minus the size of the WRITE_AND_X header. That allows for a write up
>>   * to the maximum size described by RFC1002.
>>   */
>> -#define CIFS_MAX_RFC1002_WSIZE (128 * 1024 - sizeof(WRITE_REQ) + 4)
>> +#define CIFS_MAX_RFC1002_WSIZE ((1<<17) - 1 - sizeof(WRITE_REQ) + 4)
>>
>>  /*
>>   * The default wsize is 1M. find_get_pages seems to return a maximum of 256
>
> Looks fine...
>
> If we're going to do this though, should we also consider getting rid
> of the bogus pad in the WRITE_REQ header? It's preferable to make the
> wsize as large as we can get away with...
>
> Acked-by: Jeff Layton <jlayton-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-cifs" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Steve, is there any chance to get it into 3.1?

-- 
Best regards,
Pavel Shilovsky.