src/patches/suse-2.6.27.39/patches.fixes/libiscsi-fix-data-corruption

   1 From: Mike Christie <michaelc@cs.wisc.edu>
   2 Date: Wed, 24 Sep 2008 11:46:09 -0500
   3 Subject: libiscsi: fix data corruption when target has to resend data-in packets
   4 References: bnc#472432
   5 X-Git: 1d9edf0270cb5a434d32e95279ce9493581906b3
   6
   7 iscsi_tcp was updating the exp_statsn (exp_statsn acknowledges
   8 status and tells the target it is ok to let the resources for
   9 a iscsi pdu to be reused) before it got all the data for pdu read
  10 into OS buffers. Data corruption was occuring if something happens
  11 to a packet and the network layer requests a retransmit, and the
  12 initiator has told the target about the udpated exp_statsn ack,
  13 then the target may be sending data from a buffer it has reused
  14 for a new iscsi pdu. This fixes the problem by having the LLD
  15 (iscsi_tcp in this case) just handle the transferring of data, and
  16 has libiscsi handle the processing of status (libiscsi completion
  17 processing is done after LLD data transfers are complete).
  18
  19 Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
  20 Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
  21 Signed-off-by: Hannes Reinecke <hare@suse.de>
  22 ---
  23  drivers/scsi/iscsi_tcp.c |   29 +++++------------------------
  24  drivers/scsi/libiscsi.c  |   41 +++++++++++++++++++++++++++++++++++------
  25  2 files changed, 40 insertions(+), 30 deletions(-)
  26
  27 diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
  28 index 25094c9..babe81a 100644
  29 --- a/drivers/scsi/iscsi_tcp.c
  30 +++ b/drivers/scsi/iscsi_tcp.c
  31 @@ -530,22 +530,20 @@ iscsi_tcp_cleanup_task(struct iscsi_conn *conn, struct iscsi_task *task)
  32  EXPORT_SYMBOL_GPL(iscsi_tcp_cleanup_task);
  33
  34  /**
  35 - * iscsi_data_rsp - SCSI Data-In Response processing
  36 + * iscsi_data_in - SCSI Data-In Response processing
  37   * @conn: iscsi connection
  38   * @task: scsi command task
  39   **/
  40  static int
  41 -iscsi_data_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
  42 +iscsi_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
  43  {
  44         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
  45         struct iscsi_tcp_task *tcp_task = task->dd_data;
  46         struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
  47 -       struct iscsi_session *session = conn->session;
  48 -       struct scsi_cmnd *sc = task->sc;
  49         int datasn = be32_to_cpu(rhdr->datasn);
  50 -       unsigned total_in_length = scsi_in(sc)->length;
  51 +       unsigned total_in_length = scsi_in(task->sc)->length;
  52
  53 -       iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
  54 +       iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr);
  55         if (tcp_conn->in.datalen == 0)
  56                 return 0;
  57
  58 @@ -565,23 +563,6 @@ iscsi_data_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
  59                 return ISCSI_ERR_DATA_OFFSET;
  60         }
  61
  62 -       if (rhdr->flags & ISCSI_FLAG_DATA_STATUS) {
  63 -               sc->result = (DID_OK << 16) | rhdr->cmd_status;
  64 -               conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;
  65 -               if (rhdr->flags & (ISCSI_FLAG_DATA_UNDERFLOW |
  66 -                                  ISCSI_FLAG_DATA_OVERFLOW)) {
  67 -                       int res_count = be32_to_cpu(rhdr->residual_count);
  68 -
  69 -                       if (res_count > 0 &&
  70 -                           (rhdr->flags & ISCSI_FLAG_CMD_OVERFLOW ||
  71 -                            res_count <= total_in_length))
  72 -                               scsi_in(sc)->resid = res_count;
  73 -                       else
  74 -                               sc->result = (DID_BAD_TARGET << 16) |
  75 -                                       rhdr->cmd_status;
  76 -               }
  77 -       }
  78 -
  79         conn->datain_pdus_cnt++;
  80         return 0;
  81  }
  82 @@ -781,7 +762,7 @@ iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
  83                 if (!task)
  84                         rc = ISCSI_ERR_BAD_ITT;
  85                 else
  86 -                       rc = iscsi_data_rsp(conn, task);
  87 +                       rc = iscsi_data_in(conn, task);
  88                 if (rc) {
  89                         spin_unlock(&conn->session->lock);
  90                         break;
  91 diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
  92 index e7624db..8905895 100644
  93 --- a/drivers/scsi/libiscsi.c
  94 +++ b/drivers/scsi/libiscsi.c
  95 @@ -645,6 +645,40 @@ out:
  96         __iscsi_put_task(task);
  97  }
  98
  99 +/**
 100 + * iscsi_data_in_rsp - SCSI Data-In Response processing
 101 + * @conn: iscsi connection
 102 + * @hdr:  iscsi pdu
 103 + * @task: scsi command task
 104 + **/
 105 +static void
 106 +iscsi_data_in_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 107 +                 struct iscsi_task *task)
 108 +{
 109 +       struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)hdr;
 110 +       struct scsi_cmnd *sc = task->sc;
 111 +
 112 +       if (!(rhdr->flags & ISCSI_FLAG_DATA_STATUS))
 113 +               return;
 114 +
 115 +       sc->result = (DID_OK << 16) | rhdr->cmd_status;
 116 +       conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;
 117 +       if (rhdr->flags & (ISCSI_FLAG_DATA_UNDERFLOW |
 118 +                          ISCSI_FLAG_DATA_OVERFLOW)) {
 119 +               int res_count = be32_to_cpu(rhdr->residual_count);
 120 +
 121 +               if (res_count > 0 &&
 122 +                   (rhdr->flags & ISCSI_FLAG_CMD_OVERFLOW ||
 123 +                    res_count <= scsi_in(sc)->length))
 124 +                       scsi_in(sc)->resid = res_count;
 125 +               else
 126 +                       sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
 127 +       }
 128 +
 129 +       conn->scsirsp_pdus_cnt++;
 130 +       __iscsi_put_task(task);
 131 +}
 132 +
 133  static void iscsi_tmf_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
 134  {
 135         struct iscsi_tm_rsp *tmf = (struct iscsi_tm_rsp *)hdr;
 136 @@ -911,12 +945,7 @@ int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 137                 iscsi_scsi_cmd_rsp(conn, hdr, task, data, datalen);
 138                 break;
 139         case ISCSI_OP_SCSI_DATA_IN:
 140 -               if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
 141 -                       conn->scsirsp_pdus_cnt++;
 142 -                       iscsi_update_cmdsn(session,
 143 -                                          (struct iscsi_nopin*) hdr);
 144 -                       __iscsi_put_task(task);
 145 -               }
 146 +               iscsi_data_in_rsp(conn, hdr, task);
 147                 break;
 148         case ISCSI_OP_LOGOUT_RSP:
 149                 iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);
 150 --
 151 1.6.0.2
 152