[Qemu-devel] [PATCH 12/47] block: sort BlockDeviceIoStatus errors by severity

[Paolo Bonzini]

This does not let a "failed" (EIO) status override a "nospace" status.
When several concurrent asynchronous operations fail, management will
always observe the most severe condition.

Signed-off-by: Paolo Bonzini <address@hidden>
---
 block.c          |   11 ++++++++---
 qapi-schema.json |    2 +-
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/block.c b/block.c
index 333a8fd..dce07b3 100644
--- a/block.c
+++ b/block.c
@@ -3883,9 +3883,14 @@ void bdrv_iostatus_reset(BlockDriverState *bs)
 void bdrv_iostatus_set_err(BlockDriverState *bs, int error)
 {
     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;
+    BlockDeviceIoStatus new_status =
+        (error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
+                           BLOCK_DEVICE_IO_STATUS_FAILED);
+
+    /* iostatus values are sorted from less severe to most severe
+     * (ok, nospace, failed).  */
+    if (bs->iostatus < new_status) {
+        bs->iostatus = new_status;
     }
 }
 
diff --git a/qapi-schema.json b/qapi-schema.json
index 136ce5e..2dee7c3 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -435,7 +435,7 @@
 #
 # Since: 1.0
 ##
-{ 'enum': 'BlockDeviceIoStatus', 'data': [ 'ok', 'failed', 'nospace' ] }
+{ 'enum': 'BlockDeviceIoStatus', 'data': [ 'ok', 'nospace', 'failed' ] }
 
 ##
 # @BlockInfo:
-- 
1.7.10.4