[Qemu-devel] [PATCH 1/4] scsi-disk: Implement rerror option

[Kevin Wolf <kwolf@redhat.com>]

This implements the rerror option for SCSI disks.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 blockdev.c     |    2 +-
 hw/scsi-disk.c |   91 ++++++++++++++++++++++++++++++++++++++------------------
 2 files changed, 63 insertions(+), 30 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index ff7602b..160fa84 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -326,7 +326,7 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi, int *fatal_error)
 
     on_read_error = BLOCK_ERR_REPORT;
     if ((buf = qemu_opt_get(opts, "rerror")) != NULL) {
-        if (type != IF_IDE && type != IF_VIRTIO && type != IF_NONE) {
+        if (type != IF_IDE && type != IF_VIRTIO && type != IF_SCSI && type != IF_NONE) {
             fprintf(stderr, "rerror is no supported by this format\n");
             return NULL;
         }
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index 9628b39..55ba558 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -41,7 +41,10 @@ do { fprintf(stderr, "scsi-disk: " fmt , ## __VA_ARGS__); } while (0)
 #define SCSI_DMA_BUF_SIZE    131072
 #define SCSI_MAX_INQUIRY_LEN 256
 
-#define SCSI_REQ_STATUS_RETRY 0x01
+#define SCSI_REQ_STATUS_RETRY           0x01
+#define SCSI_REQ_STATUS_RETRY_TYPE_MASK 0x06
+#define SCSI_REQ_STATUS_RETRY_READ      0x00
+#define SCSI_REQ_STATUS_RETRY_WRITE     0x02
 
 typedef struct SCSIDiskState SCSIDiskState;
 
@@ -70,6 +73,8 @@ struct SCSIDiskState
     char *serial;
 };
 
+static int scsi_handle_rw_error(SCSIDiskReq *r, int error, int type);
+
 static SCSIDiskReq *scsi_new_request(SCSIDiskState *s, uint32_t tag,
         uint32_t lun)
 {
@@ -127,34 +132,30 @@ static void scsi_cancel_io(SCSIDevice *d, uint32_t tag)
 static void scsi_read_complete(void * opaque, int ret)
 {
     SCSIDiskReq *r = (SCSIDiskReq *)opaque;
+    int n;
 
     r->req.aiocb = NULL;
 
     if (ret) {
-        DPRINTF("IO error\n");
-        r->req.bus->complete(r->req.bus, SCSI_REASON_DATA, r->req.tag, 0);
-        scsi_command_complete(r, CHECK_CONDITION, NO_SENSE);
-        return;
+        if (scsi_handle_rw_error(r, -ret, SCSI_REQ_STATUS_RETRY_READ)) {
+            return;
+        }
     }
+
     DPRINTF("Data ready tag=0x%x len=%zd\n", r->req.tag, r->iov.iov_len);
 
+    n = r->iov.iov_len / 512;
+    r->sector += n;
+    r->sector_count -= n;
     r->req.bus->complete(r->req.bus, SCSI_REASON_DATA, r->req.tag, r->iov.iov_len);
 }
 
-/* Read more data from scsi device into buffer.  */
-static void scsi_read_data(SCSIDevice *d, uint32_t tag)
+
+static void scsi_read_request(SCSIDiskReq *r)
 {
-    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, d);
-    SCSIDiskReq *r;
+    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
     uint32_t n;
 
-    r = scsi_find_request(s, tag);
-    if (!r) {
-        BADF("Bad read tag 0x%x\n", tag);
-        /* ??? This is the wrong error.  */
-        scsi_command_complete(r, CHECK_CONDITION, HARDWARE_ERROR);
-        return;
-    }
     if (r->sector_count == (uint32_t)-1) {
         DPRINTF("Read buf_len=%zd\n", r->iov.iov_len);
         r->sector_count = 0;
@@ -177,14 +178,34 @@ static void scsi_read_data(SCSIDevice *d, uint32_t tag)
                               scsi_read_complete, r);
     if (r->req.aiocb == NULL)
         scsi_command_complete(r, CHECK_CONDITION, HARDWARE_ERROR);
-    r->sector += n;
-    r->sector_count -= n;
 }
 
-static int scsi_handle_write_error(SCSIDiskReq *r, int error)
+/* Read more data from scsi device into buffer.  */
+static void scsi_read_data(SCSIDevice *d, uint32_t tag)
 {
+    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, d);
+    SCSIDiskReq *r;
+
+    r = scsi_find_request(s, tag);
+    if (!r) {
+        BADF("Bad read tag 0x%x\n", tag);
+        /* ??? This is the wrong error.  */
+        scsi_command_complete(r, CHECK_CONDITION, HARDWARE_ERROR);
+        return;
+    }
+
+    if (r->req.aiocb) {
+        BADF("Data transfer already in progress\n");
+    }
+
+    scsi_read_request(r);
+}
+
+static int scsi_handle_rw_error(SCSIDiskReq *r, int error, int type)
+{
+    int is_read = (type == SCSI_REQ_STATUS_RETRY_READ);
     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
-    BlockErrorAction action = bdrv_get_on_error(s->bs, 0);
+    BlockErrorAction action = bdrv_get_on_error(s->bs, is_read);
 
     if (action == BLOCK_ERR_IGNORE) {
         bdrv_mon_event(s->bs, BDRV_ACTION_IGNORE, 0);
@@ -193,10 +214,16 @@ static int scsi_handle_write_error(SCSIDiskReq *r, int error)
 
     if ((error == ENOSPC && action == BLOCK_ERR_STOP_ENOSPC)
             || action == BLOCK_ERR_STOP_ANY) {
-        r->status |= SCSI_REQ_STATUS_RETRY;
+
+        type &= SCSI_REQ_STATUS_RETRY_TYPE_MASK;
+        r->status |= SCSI_REQ_STATUS_RETRY | type;
+
         bdrv_mon_event(s->bs, BDRV_ACTION_STOP, 0);
         vm_stop(0);
     } else {
+        if (type == SCSI_REQ_STATUS_RETRY_READ) {
+            r->req.bus->complete(r->req.bus, SCSI_REASON_DATA, r->req.tag, 0);
+        }
         scsi_command_complete(r, CHECK_CONDITION,
                 HARDWARE_ERROR);
         bdrv_mon_event(s->bs, BDRV_ACTION_REPORT, 0);
@@ -214,8 +241,9 @@ static void scsi_write_complete(void * opaque, int ret)
     r->req.aiocb = NULL;
 
     if (ret) {
-        if (scsi_handle_write_error(r, -ret))
+        if (scsi_handle_rw_error(r, -ret, SCSI_REQ_STATUS_RETRY_WRITE)) {
             return;
+        }
     }
 
     n = r->iov.iov_len / 512;
@@ -288,8 +316,18 @@ static void scsi_dma_restart_bh(void *opaque)
     QTAILQ_FOREACH(req, &s->qdev.requests, next) {
         r = DO_UPCAST(SCSIDiskReq, req, req);
         if (r->status & SCSI_REQ_STATUS_RETRY) {
-            r->status &= ~SCSI_REQ_STATUS_RETRY;
-            scsi_write_request(r); 
+            int status = r->status;
+            r->status &=
+                ~(SCSI_REQ_STATUS_RETRY | SCSI_REQ_STATUS_RETRY_TYPE_MASK);
+
+            switch (status & SCSI_REQ_STATUS_RETRY_TYPE_MASK) {
+            case SCSI_REQ_STATUS_RETRY_READ:
+                scsi_read_request(r);
+                break;
+            case SCSI_REQ_STATUS_RETRY_WRITE:
+                scsi_write_request(r);
+                break;
+            }
         }
     }
 }
@@ -1152,11 +1190,6 @@ static int scsi_disk_initfn(SCSIDevice *dev)
         return -1;
     }
 
-    if (bdrv_get_on_error(s->bs, 1) != BLOCK_ERR_REPORT) {
-        error_report("Device doesn't support drive option rerror");
-        return -1;
-    }
-
     if (!s->serial) {
         /* try to fall back to value set with legacy -drive serial=... */
         dinfo = drive_get_by_blockdev(s->bs);
-- 
1.7.2.3