Re: mids and cifs sendrcv2

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Fri, Apr 15, 2011 at 5:45 AM, Pavel Shilovsky <piastryyy@xxxxxxxxx> wrote:
> 2011/4/8 Steve French <smfrench@xxxxxxxxx>:
>> Update on cifs vs. smb2 mids, and the smb2 sendrcv2.   Jeff had
>> suggested more closely matching the cifs and smb2 mids, in particular
>> extending the 16 bit cifs mid (multiplex identifier for inflight
>> network requests) to the 64 bit size needed for smb2 (and thus masking
>> the mid when used for cifs) and having cifs ignore the various smb2
>> unique fields in the mid (which makes the mid larger for cifs).
>> Since the smb2 code in cifs-2.6.git (put in February and early March)
>> has now been rereviewed, the next step in the smb2 merge is posting
>> and reviewing the transport routine for smb2 (smb2_sendrcv2 or reusing
>> cifs_sendrcv2) - the latter may make more sense if we go to a common
>> mid for cifs and smb2.   At the fs summit, Jeff and Jeremy and I
>> talked about this, but Pavel and others may have opinions on this
>> topic.   As soon as the cifs merge activity settles down for 2.6.39, I
>> plan to post sendrcv2 alternatives and then begin work with Pavel on
>> the superblock, file and inode routines and seeing whether for smb2
>> they should be smb2 unique (as we originally expected since smb2 is
>> handle based, and simpler) and look more like they did in the smb2.ko
>> work that Pavel did last summer or should be more common with the cifs
>> routines.
>>
>> --
>> Thanks,
>>
>> Steve
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-cifs" in
>> the body of a message to majordomo@xxxxxxxxxxxxxxx
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>
> I suggest to make cifs and smb2 protocol mid structures use common
> structure that has equals fields for both and then expand this
> structure for protocol-dependent things.
>
> It can look like this:
>
> /* one of these for every pending CIFS request to the server */
> struct mid_q_entry {
>        __u8 protocol_id;
>        struct list_head qhead; /* mids waiting on reply from this server */
>        int midState;   /* wish this were enum but can not pass to wait_event */
>        unsigned long when_alloc;  /* when mid was created */
> #ifdef CONFIG_CIFS_STATS2
>        unsigned long when_sent; /* time when smb send finished */
>        unsigned long when_received; /* when demux complete (taken off wire) */
> #endif
>        bool largeBuf:1;        /* if valid response, is pointer to large buf */
>        void *resp_buf;         /* response buffer */
>        mid_callback_t *callback; /* call completion callback */
>        void *callback_data;      /* general purpose pointer for callback */
> };
>
> struct cifs_mid_q_entry {
>        struct mid_q_entry mid_q;
>        __u16 mid;              /* multiplex id */
>        __u32 sequence_number;  /* for CIFS signing */
>        __u8 command;           /* smb command code */
>        __u16 pid;              /* process id */
>        bool multiRsp:1;        /* multiple trans2 responses for one request  */
>        bool multiEnd:1;        /* both received */
> };
>
> struct smb2_mid_q_entry {
>        struct mid_q_entry mid_q;
>        __u64 mid;              /* multiplex id(s), bigger for smb2 */
>        __le16 command;         /* smb2 command code */
>        __u32 pid;              /* process id - bigger for smb2 than cifs */
> };

I think nested mid structures (around a base of common mid fields)
like the above is going to be the easiest way to handle the differences.

I don't understand your PROTOCOL_ID #define though - we
identify smb2 vs. cifs via a bool in the tcp server info struct,
and presumably if we don't have access to the tcp server
info struct we would have to add a field in the base mid
(struct mid_q_entry) that indicates smb2 vs. cifs..


> So, we always work with a pointer to common structure mid_q_entry and
> then expand it according to protocol_id filed when we need it:
>
> #define PROTOCOL_ID(mid) (*((__u8 *)mid))
>
> process_mid(struct mid_q_entry *pmid)
> {
>        if (PROTOCOL_ID(pmid) == SMB2)
>                process_smb2_mid((struct smb2_mid_q_entry *)pmid);
>        else
>                process_cifs_mid((struct cifs_mid_q_entry *)pmid);
> }
>
>
> --
> Best regards,
> Pavel Shilovsky.
>



-- 
Thanks,

Steve
--
To unsubscribe from this list: send the line "unsubscribe linux-cifs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux