[Qemu-devel] [RFC PATCH 11/36] block: reorganize io error code

[Paolo Bonzini <pbonzini@redhat.com>]

Move the common part of IDE/SCSI/virtio error handling to the block
layer.  The same scheme will be used for errors in block jobs.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 block.c         |   46 ++++++++++++++++++++++++++++++++++++++--------
 block.h         |    5 +++--
 hw/ide/core.c   |   20 +++++---------------
 hw/scsi-disk.c  |   23 +++++++----------------
 hw/virtio-blk.c |   19 +++++--------------
 qemu-tool.c     |    6 ++++++
 6 files changed, 64 insertions(+), 55 deletions(-)

diff --git a/block.c b/block.c
index 878b712..4011ce4 100644
--- a/block.c
+++ b/block.c
@@ -29,6 +29,7 @@
 #include "blockjob.h"
 #include "module.h"
 #include "qjson.h"
+#include "sysemu.h"
 #include "qemu-coroutine.h"
 #include "qmp-commands.h"
 #include "qemu-timer.h"
@@ -1158,8 +1159,8 @@ void bdrv_set_dev_ops(BlockDriverState *bs, const BlockDevOps *ops,
     }
 }
 
-void bdrv_emit_qmp_error_event(const BlockDriverState *bdrv,
-                               BlockErrorAction action, int is_read)
+static void bdrv_emit_qmp_error_event(const BlockDriverState *bdrv,
+                                      BlockErrorAction action, int is_read)
 {
     QObject *data;
     const char *action_str;
@@ -2397,6 +2398,39 @@ BlockdevOnError bdrv_get_on_error(BlockDriverState *bs, int is_read)
     return is_read ? bs->on_read_error : bs->on_write_error;
 }
 
+BlockErrorAction bdrv_get_error_action(BlockDriverState *bs, int is_read, int error)
+{
+    BlockdevOnError on_err = is_read ? bs->on_read_error : bs->on_write_error;
+
+    switch (on_err) {
+    case BLOCKDEV_ON_ERROR_ENOSPC:
+        return (error == ENOSPC) ? BDRV_ACTION_STOP : BDRV_ACTION_REPORT;
+    case BLOCKDEV_ON_ERROR_STOP:
+        return BDRV_ACTION_STOP;
+    case BLOCKDEV_ON_ERROR_REPORT:
+        return BDRV_ACTION_REPORT;
+    case BLOCKDEV_ON_ERROR_IGNORE:
+        return BDRV_ACTION_IGNORE;
+    default:
+        abort();
+    }
+}
+
+/* This is done by device models because, while the block layer knows
+ * about the error, it does not know whether an operation comes from
+ * the device or the block layer (from a job, for example).
+ */
+void bdrv_error_action(BlockDriverState *bs, BlockErrorAction action,
+                       int is_read, int error)
+{
+    assert(error >= 0);
+    bdrv_emit_qmp_error_event(bs, action, is_read);
+    if (action == BDRV_ACTION_STOP) {
+        vm_stop(RUN_STATE_IO_ERROR);
+        bdrv_iostatus_set_err(bs, error);
+    }
+}
+
 int bdrv_is_read_only(BlockDriverState *bs)
 {
     return bs->read_only;
@@ -4096,14 +4130,10 @@ void bdrv_iostatus_reset(BlockDriverState *bs)
     }
 }
 
-/* XXX: Today this is set by device models because it makes the implementation
-   quite simple. However, the block layer knows about the error, so it's
-   possible to implement this without device models being involved */
 void bdrv_iostatus_set_err(BlockDriverState *bs, int error)
 {
-    if (bdrv_iostatus_is_enabled(bs) &&
-        bs->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
-        assert(error >= 0);
+    assert(bdrv_iostatus_is_enabled(bs));
+    if (bs->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
         bs->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
                                          BLOCK_DEVICE_IO_STATUS_FAILED;
     }
diff --git a/block.h b/block.h
index 32f8fc5..32b075c 100644
--- a/block.h
+++ b/block.h
@@ -97,8 +97,6 @@ void bdrv_iostatus_reset(BlockDriverState *bs);
 void bdrv_iostatus_disable(BlockDriverState *bs);
 bool bdrv_iostatus_is_enabled(const BlockDriverState *bs);
 void bdrv_iostatus_set_err(BlockDriverState *bs, int error);
-void bdrv_emit_qmp_error_event(const BlockDriverState *bdrv,
-                               BlockErrorAction action, int is_read);
 void bdrv_info_print(Monitor *mon, const QObject *data);
 void bdrv_info(Monitor *mon, QObject **ret_data);
 void bdrv_stats_print(Monitor *mon, const QObject *data);
@@ -286,6 +284,9 @@ int bdrv_get_translation_hint(BlockDriverState *bs);
 void bdrv_set_on_error(BlockDriverState *bs, BlockdevOnError on_read_error,
                        BlockdevOnError on_write_error);
 BlockdevOnError bdrv_get_on_error(BlockDriverState *bs, int is_read);
+BlockErrorAction bdrv_get_error_action(BlockDriverState *bs, int is_read, int error);
+void bdrv_error_action(BlockDriverState *bs, BlockErrorAction action,
+                       int is_read, int error);
 int bdrv_is_read_only(BlockDriverState *bs);
 int bdrv_is_sg(BlockDriverState *bs);
 int bdrv_enable_write_cache(BlockDriverState *bs);
diff --git a/hw/ide/core.c b/hw/ide/core.c
index 2fb584f..b71fbda 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -558,31 +558,21 @@ void ide_dma_error(IDEState *s)
 static int ide_handle_rw_error(IDEState *s, int error, int op)
 {
     int is_read = (op & BM_STATUS_RETRY_READ);
-    BlockdevOnError action = bdrv_get_on_error(s->bs, is_read);
+    BlockErrorAction action = bdrv_get_error_action(s->bs, is_read, error);
 
-    if (action == BLOCKDEV_ON_ERROR_IGNORE) {
-        bdrv_emit_qmp_error_event(s->bs, BDRV_ACTION_IGNORE, is_read);
-        return 0;
-    }
-
-    if ((error == ENOSPC && action == BLOCKDEV_ON_ERROR_ENOSPC)
-            || action == BLOCKDEV_ON_ERROR_STOP) {
+    if (action == BDRV_ACTION_STOP) {
         s->bus->dma->ops->set_unit(s->bus->dma, s->unit);
         s->bus->error_status = op;
-        bdrv_emit_qmp_error_event(s->bs, BDRV_ACTION_STOP, is_read);
-        vm_stop(RUN_STATE_IO_ERROR);
-        bdrv_iostatus_set_err(s->bs, error);
-    } else {
+    } else if (action == BDRV_ACTION_REPORT) {
         if (op & BM_STATUS_DMA_RETRY) {
             dma_buf_commit(s);
             ide_dma_error(s);
         } else {
             ide_rw_error(s);
         }
-        bdrv_emit_qmp_error_event(s->bs, BDRV_ACTION_REPORT, is_read);
     }
-
-    return 1;
+    bdrv_error_action(s->bs, action, is_read, error);
+    return action != BDRV_ACTION_IGNORE;
 }
 
 void ide_dma_cb(void *opaque, int ret)
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index b196328..a58b109 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -390,21 +390,9 @@ static int scsi_handle_rw_error(SCSIDiskReq *r, int error)
 {
     int is_read = (r->req.cmd.xfer == SCSI_XFER_FROM_DEV);
     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
-    BlockdevOnError action = bdrv_get_on_error(s->qdev.conf.bs, is_read);
+    BlockErrorAction action = bdrv_get_error_action(s->qdev.conf.bs, is_read, error);
 
-    if (action == BLOCKDEV_ON_ERROR_IGNORE) {
-        bdrv_emit_qmp_error_event(s->qdev.conf.bs, BDRV_ACTION_IGNORE, is_read);
-        return 0;
-    }
-
-    if ((error == ENOSPC && action == BLOCKDEV_ON_ERROR_ENOSPC)
-            || action == BLOCKDEV_ON_ERROR_STOP) {
-
-        bdrv_emit_qmp_error_event(s->qdev.conf.bs, BDRV_ACTION_STOP, is_read);
-        vm_stop(RUN_STATE_IO_ERROR);
-        bdrv_iostatus_set_err(s->qdev.conf.bs, error);
-        scsi_req_retry(&r->req);
-    } else {
+    if (action == BDRV_ACTION_REPORT) {
         switch (error) {
         case ENOMEDIUM:
             scsi_check_condition(r, SENSE_CODE(NO_MEDIUM));
@@ -419,9 +407,12 @@ static int scsi_handle_rw_error(SCSIDiskReq *r, int error)
             scsi_check_condition(r, SENSE_CODE(IO_ERROR));
             break;
         }
-        bdrv_emit_qmp_error_event(s->qdev.conf.bs, BDRV_ACTION_REPORT, is_read);
     }
-    return 1;
+    bdrv_error_action(s->qdev.conf.bs, action, is_read, error);
+    if (action == BDRV_ACTION_STOP) {
+        scsi_req_retry(&r->req);
+    }
+    return action != BDRV_ACTION_IGNORE;
 }
 
 static void scsi_write_complete(void * opaque, int ret)
diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
index 29f93af..2599326 100644
--- a/hw/virtio-blk.c
+++ b/hw/virtio-blk.c
@@ -65,29 +65,20 @@ static void virtio_blk_req_complete(VirtIOBlockReq *req, int status)
 static int virtio_blk_handle_rw_error(VirtIOBlockReq *req, int error,
     int is_read)
 {
-    BlockdevOnError action = bdrv_get_on_error(req->dev->bs, is_read);
+    BlockErrorAction action = bdrv_get_error_action(req->dev->bs, is_read, error);
     VirtIOBlock *s = req->dev;
 
-    if (action == BLOCKDEV_ON_ERROR_IGNORE) {
-        bdrv_emit_qmp_error_event(s->bs, BDRV_ACTION_IGNORE, is_read);
-        return 0;
-    }
-
-    if ((error == ENOSPC && action == BLOCKDEV_ON_ERROR_ENOSPC)
-            || action == BLOCKDEV_ON_ERROR_STOP) {
+    if (action == BDRV_ACTION_STOP) {
         req->next = s->rq;
         s->rq = req;
-        bdrv_emit_qmp_error_event(s->bs, BDRV_ACTION_STOP, is_read);
-        vm_stop(RUN_STATE_IO_ERROR);
-        bdrv_iostatus_set_err(s->bs, error);
-    } else {
+    } else if (action == BDRV_ACTION_REPORT) {
         virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
         bdrv_acct_done(s->bs, &req->acct);
         g_free(req);
-        bdrv_emit_qmp_error_event(s->bs, BDRV_ACTION_REPORT, is_read);
     }
 
-    return 1;
+    bdrv_error_action(s->bs, action, is_read, error);
+    return action != BDRV_ACTION_IGNORE;
 }
 
 static void virtio_blk_rw_complete(void *opaque, int ret)
diff --git a/qemu-tool.c b/qemu-tool.c
index 07fc4f2..fd754d6 100644
--- a/qemu-tool.c
+++ b/qemu-tool.c
@@ -19,6 +19,7 @@
 #include "qemu-log.h"
 #include "migration.h"
 #include "main-loop.h"
+#include "sysemu.h"
 #include "qemu_socket.h"
 #include "slirp/libslirp.h"
 
@@ -34,6 +35,11 @@ struct QEMUBH
 
 Monitor *cur_mon;
 
+void vm_stop(RunState state)
+{
+    abort();
+}
+
 int monitor_cur_is_qmp(void)
 {
     return 0;
-- 
1.7.10.2