[PATCH 05/10] scsi-disk: pass guest recoverable errors through even for rerror=stop

From: Paolo Bonzini <pbonzini@redhat.com>
To: qemu-devel@nongnu.org
Cc: hare@suse.de
Subject: [PATCH 05/10] scsi-disk: pass guest recoverable errors through even for rerror=stop
Date: Wed, 24 Feb 2021 19:24:48 +0100	[thread overview]
Message-ID: <20210224182453.587731-6-pbonzini@redhat.com> (raw)
In-Reply-To: <20210224182453.587731-1-pbonzini@redhat.com>

Right now, recoverable sense values are only passed directly to the
guest only for rerror=report.  However, when rerror/werror are 'stop'
we still don't want the host to be involved on every UNIT ATTENTION
(especially considered that the QMP event will not have enough information
to act on the report).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/scsi/scsi-disk.c | 51 +++++++++++++++++++++++++--------------------
 1 file changed, 28 insertions(+), 23 deletions(-)

diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
index 548a5297fa..a5a58d7db3 100644
--- a/hw/scsi/scsi-disk.c
+++ b/hw/scsi/scsi-disk.c
@@ -212,39 +212,44 @@ static bool scsi_handle_rw_error(SCSIDiskReq *r, int ret, bool acct_failed)
         }
     }
 
-    action = blk_get_error_action(s->qdev.conf.blk, is_read, error);
-    if (action == BLOCK_ERROR_ACTION_REPORT) {
+    /*
+     * Check whether the error has to be handled by the guest or should
+     * rather follow the rerror=/werror= settings.  Guest-handled errors
+     * are usually retried immediately, so do not post them to QMP and
+     * do not account them as failed I/O.
+     */
+    if (req_has_sense &&
+        scsi_sense_buf_is_guest_recoverable(r->req.sense, sizeof(r->req.sense))) {
+        action = BLOCK_ERROR_ACTION_REPORT;
+        acct_failed = false;
+    } else {
+        action = blk_get_error_action(s->qdev.conf.blk, is_read, error);
+        blk_error_action(s->qdev.conf.blk, action, is_read, error);
+    }
+
+    switch (action) {
+    case BLOCK_ERROR_ACTION_REPORT:
         if (acct_failed) {
             block_acct_failed(blk_get_stats(s->qdev.conf.blk), &r->acct);
         }
         if (req_has_sense) {
-            /* A passthrough command has run and has produced sense data; check
-             * whether the error has to be handled by the guest or should rather
-             * pause the host.
-             */
-            if (scsi_sense_buf_is_guest_recoverable(r->req.sense, sizeof(r->req.sense))) {
-                /* These errors are handled by guest. */
-                sdc->update_sense(&r->req);
-                scsi_req_complete(&r->req, status);
-                return true;
-            }
-        } else {
-            if (status == CHECK_CONDITION) {
-                scsi_req_build_sense(&r->req, sense);
-            }
-            scsi_req_complete(&r->req, status);
+            sdc->update_sense(&r->req);
+        } else if (status == CHECK_CONDITION) {
+            scsi_req_build_sense(&r->req, sense);
         }
-    }
+        scsi_req_complete(&r->req, status);
+        return true;
 
-    blk_error_action(s->qdev.conf.blk, action, is_read, error);
-    if (action == BLOCK_ERROR_ACTION_IGNORE) {
+    case BLOCK_ERROR_ACTION_IGNORE:
         return false;
-    }
 
-    if (action == BLOCK_ERROR_ACTION_STOP) {
+    case BLOCK_ERROR_ACTION_STOP:
         scsi_req_retry(&r->req);
+        return true;
+
+    default:
+        g_assert_not_reached();
     }
-    return true;
 }
 
 static bool scsi_disk_req_check_error(SCSIDiskReq *r, int ret, bool acct_failed)
-- 
2.29.2



