merged with minor fix to remove checkpatch warning
On Thu, Feb 10, 2011 at 7:05 AM, Jeff Layton <jlayton@xxxxxxxxxx> wrote:
> Slight revision to this patch...use min_t() instead of conditional
> assignment. Also, remove the FIXME comment and replace it with the
> explanation that Steve gave earlier.
>
> After receiving a packet, we currently check the header. If it's no
> good, then we toss it out and continue the loop, leaving the caller
> waiting on that response.
>
> In cases where the packet has length inconsistencies, but the MID is
> valid, this leads to unneeded delays. That's especially problematic now
> that the client waits indefinitely for responses.
>
> Instead, don't immediately discard the packet if checkSMB fails. Try to
> find a matching mid_q_entry, mark it as having a malformed response and
> issue the callback.
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> fs/cifs/cifsglob.h | 2 +-
> fs/cifs/connect.c | 30 ++++++++++++++++++++++++------
> fs/cifs/transport.c | 3 +++
> 3 files changed, 28 insertions(+), 7 deletions(-)
>
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index 1ab33eb..17afb0f 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -654,7 +654,7 @@ static inline void free_dfs_info_array(struct dfs_info3_param *param,
> #define MID_REQUEST_SUBMITTED 2
> #define MID_RESPONSE_RECEIVED 4
> #define MID_RETRY_NEEDED 8 /* session closed while this request out */
> -#define MID_NO_RESP_NEEDED 0x10
> +#define MID_RESPONSE_MALFORMED 0x10
>
> /* Types of response buffer returned from SendReceive2 */
> #define CIFS_NO_BUFFER 0 /* Response buffer not returned */
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index 161f24c..eb56e0f 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -586,11 +586,20 @@ incomplete_rcv:
> total_read += 4; /* account for rfc1002 hdr */
>
> dump_smb(smb_buffer, total_read);
> - if (checkSMB(smb_buffer, smb_buffer->Mid, total_read)) {
> +
> + /*
> + * We know that we received enough to get to the MID as we
> + * checked the pdu_length earlier. Now check to see
> + * if the rest of the header is OK. We borrow the length
> + * var for the rest of the loop to avoid a new stack var.
> + *
> + * 48 bytes is enough to display the header and a little bit
> + * into the payload for debugging purposes.
> + */
> + length = checkSMB(smb_buffer, smb_buffer->Mid, total_read);
> + if (length != 0)
> cifs_dump_mem("Bad SMB: ", smb_buffer,
> - total_read < 48 ? total_read : 48);
> - continue;
> - }
> + min_t(unsigned int, total_read, 48));
>
> mid_entry = NULL;
> server->lstrp = jiffies;
> @@ -602,7 +611,8 @@ incomplete_rcv:
> if ((mid_entry->mid == smb_buffer->Mid) &&
> (mid_entry->midState == MID_REQUEST_SUBMITTED) &&
> (mid_entry->command == smb_buffer->Command)) {
> - if (check2ndT2(smb_buffer,server->maxBuf) > 0) {
> + if (length == 0 &&
> + check2ndT2(smb_buffer,server->maxBuf) > 0) {
> /* We have a multipart transact2 resp */
> isMultiRsp = true;
> if (mid_entry->resp_buf) {
> @@ -637,7 +647,12 @@ incomplete_rcv:
> mid_entry->resp_buf = smb_buffer;
> mid_entry->largeBuf = isLargeBuf;
> multi_t2_fnd:
> - mid_entry->midState = MID_RESPONSE_RECEIVED;
> + if (length == 0)
> + mid_entry->midState =
> + MID_RESPONSE_RECEIVED;
> + else
> + mid_entry->midState =
> + MID_RESPONSE_MALFORMED;
> #ifdef CONFIG_CIFS_STATS2
> mid_entry->when_received = jiffies;
> #endif
> @@ -658,6 +673,9 @@ multi_t2_fnd:
> else
> smallbuf = NULL;
> }
> + } else if (length != 0) {
> + /* response sanity checks failed */
> + continue;
> } else if (!is_valid_oplock_break(smb_buffer, server) &&
> !isMultiRsp) {
> cERROR(1, "No task to wake, unknown frame received! "
> diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
> index fbc5aac..46d8756 100644
> --- a/fs/cifs/transport.c
> +++ b/fs/cifs/transport.c
> @@ -457,6 +457,9 @@ sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server)
> case MID_RETRY_NEEDED:
> rc = -EAGAIN;
> break;
> + case MID_RESPONSE_MALFORMED:
> + rc = -EIO;
> + break;
> default:
> cERROR(1, "%s: invalid mid state mid=%d state=%d", __func__,
> mid->mid, mid->midState);
> --
> 1.7.4
>
>
--
Thanks,
Steve
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