qcow2: Flushing the caches in qcow2_close may fail

qcow2_cache_flush() may fail; if one of the caches failed to be flushed
successfully to disk in qcow2_close() the image should not be marked
clean, and we should emit a warning.

This breaks the (qcow2-specific) iotests 026, 071 and 089; change their
output accordingly.

Cc: qemu-stable@nongnu.org
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
(cherry picked from commit 3b5e14c7)
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

block/qcow2.c

@@ -1428,10 +1428,23 @@ static void qcow2_close(BlockDriverState *bs)
     s->l1_table = NULL;
 
     if (!(bs->open_flags & BDRV_O_INCOMING)) {
-        qcow2_cache_flush(bs, s->l2_table_cache);
-        qcow2_cache_flush(bs, s->refcount_block_cache);
+        int ret1, ret2;
 
-        qcow2_mark_clean(bs);
+        ret1 = qcow2_cache_flush(bs, s->l2_table_cache);
+        ret2 = qcow2_cache_flush(bs, s->refcount_block_cache);
+
+        if (ret1) {
+            error_report("Failed to flush the L2 table cache: %s",
+                         strerror(-ret1));
+        }
+        if (ret2) {
+            error_report("Failed to flush the refcount block cache: %s",
+                         strerror(-ret2));
+        }
+
+        if (!ret1 && !ret2) {
+            qcow2_mark_clean(bs);
+        }
     }
 
     qcow2_cache_destroy(bs, s->l2_table_cache);

tests/qemu-iotests/071.out

@@ -30,10 +30,14 @@ blkverify: read sector_num=0 nb_sectors=4 contents mismatch in sector 0
 
 === Testing blkdebug through filename ===
 
+Failed to flush the L2 table cache: Input/output error
+Failed to flush the refcount block cache: Input/output error
 read failed: Input/output error
 
 === Testing blkdebug through file blockref ===
 
+Failed to flush the L2 table cache: Input/output error
+Failed to flush the refcount block cache: Input/output error
 read failed: Input/output error
 
 === Testing blkdebug on existing block device ===
@@ -48,6 +52,8 @@ read failed: Input/output error
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN"}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "DEVICE_TRAY_MOVED", "data": {"device": "ide1-cd0", "tray-open": true}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "DEVICE_TRAY_MOVED", "data": {"device": "floppy0", "tray-open": true}}
+qemu-system-x86_64: Failed to flush the L2 table cache: Input/output error
+qemu-system-x86_64: Failed to flush the refcount block cache: Input/output error
 
 
 === Testing blkverify on existing block device ===
@@ -86,5 +92,7 @@ read failed: Input/output error
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN"}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "DEVICE_TRAY_MOVED", "data": {"device": "ide1-cd0", "tray-open": true}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "DEVICE_TRAY_MOVED", "data": {"device": "floppy0", "tray-open": true}}
+qemu-system-x86_64: Failed to flush the L2 table cache: Input/output error
+qemu-system-x86_64: Failed to flush the refcount block cache: Input/output error
 
 *** done

tests/qemu-iotests/089.out

@@ -24,6 +24,8 @@ read 512/512 bytes at offset 0
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 
 wrote 512/512 bytes at offset 229376
 512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Failed to flush the L2 table cache: Input/output error
+Failed to flush the refcount block cache: Input/output error
 read failed: Input/output error
 
 === Testing qemu-img info output ===