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[SCSI] libiscsi: fix data corruption when target has to resend data-in packets

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iscsi_tcp was updating the exp_statsn (exp_statsn acknowledges
status and tells the target it is ok to let the resources for
a iscsi pdu to be reused) before it got all the data for pdu read
into OS buffers. Data corruption was occuring if something happens
to a packet and the network layer requests a retransmit, and the
initiator has told the target about the udpated exp_statsn ack,
then the target may be sending data from a buffer it has reused
for a new iscsi pdu. This fixes the problem by having the LLD
(iscsi_tcp in this case) just handle the transferring of data, and
has libiscsi handle the processing of status (libiscsi completion
processing is done after LLD data transfers are complete).

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
This commit is contained in:
Mike Christie 2008-09-24 11:46:09 -05:00 committed by James Bottomley
parent cbdc14459b
commit 1d9edf0270
2 changed files with 40 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
drivers/scsi/iscsi_tcp.c
View File

@ -523,22 +523,20 @@ iscsi_tcp_cleanup_task(struct iscsi_conn *conn, struct iscsi_task *task)
}
/**
* iscsi_data_rsp - SCSI Data-In Response processing
* iscsi_data_in - SCSI Data-In Response processing
* @conn: iscsi connection
* @task: scsi command task
**/
static int
iscsi_data_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
iscsi_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
{
struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
struct iscsi_tcp_task *tcp_task = task->dd_data;
struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
struct iscsi_session *session = conn->session;
struct scsi_cmnd *sc = task->sc;
int datasn = be32_to_cpu(rhdr->datasn);
unsigned total_in_length = scsi_in(sc)->length;
unsigned total_in_length = scsi_in(task->sc)->length;
iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr);
if (tcp_conn->in.datalen == 0)
return 0;
@ -558,23 +556,6 @@ iscsi_data_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
return ISCSI_ERR_DATA_OFFSET;
}
if (rhdr->flags & ISCSI_FLAG_DATA_STATUS) {
sc->result = (DID_OK << 16) | rhdr->cmd_status;
conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;
if (rhdr->flags & (ISCSI_FLAG_DATA_UNDERFLOW |
ISCSI_FLAG_DATA_OVERFLOW)) {
int res_count = be32_to_cpu(rhdr->residual_count);
if (res_count > 0 &&
(rhdr->flags & ISCSI_FLAG_CMD_OVERFLOW ||
res_count <= total_in_length))
scsi_in(sc)->resid = res_count;
else
sc->result = (DID_BAD_TARGET << 16) |
rhdr->cmd_status;
}
}
conn->datain_pdus_cnt++;
return 0;
}
@ -774,7 +755,7 @@ iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
if (!task)
rc = ISCSI_ERR_BAD_ITT;
else
rc = iscsi_data_rsp(conn, task);
rc = iscsi_data_in(conn, task);
if (rc) {
spin_unlock(&conn->session->lock);
break;

41
drivers/scsi/libiscsi.c
View File

@ -633,6 +633,40 @@ out:
__iscsi_put_task(task);
}
/**
* iscsi_data_in_rsp - SCSI Data-In Response processing
* @conn: iscsi connection
* @hdr: iscsi pdu
* @task: scsi command task
**/
static void
iscsi_data_in_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
struct iscsi_task *task)
{
struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)hdr;
struct scsi_cmnd *sc = task->sc;
if (!(rhdr->flags & ISCSI_FLAG_DATA_STATUS))
return;
sc->result = (DID_OK << 16) | rhdr->cmd_status;
conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;
if (rhdr->flags & (ISCSI_FLAG_DATA_UNDERFLOW |
ISCSI_FLAG_DATA_OVERFLOW)) {
int res_count = be32_to_cpu(rhdr->residual_count);
if (res_count > 0 &&
(rhdr->flags & ISCSI_FLAG_CMD_OVERFLOW ||
res_count <= scsi_in(sc)->length))
scsi_in(sc)->resid = res_count;
else
sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
}
conn->scsirsp_pdus_cnt++;
__iscsi_put_task(task);
}
static void iscsi_tmf_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
{
struct iscsi_tm_rsp *tmf = (struct iscsi_tm_rsp *)hdr;
@ -818,12 +852,7 @@ int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
iscsi_scsi_cmd_rsp(conn, hdr, task, data, datalen);
break;
case ISCSI_OP_SCSI_DATA_IN:
if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
conn->scsirsp_pdus_cnt++;
iscsi_update_cmdsn(session,
(struct iscsi_nopin*) hdr);
__iscsi_put_task(task);
}
iscsi_data_in_rsp(conn, hdr, task);
break;
case ISCSI_OP_LOGOUT_RSP:
iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);