diff --git a/block/qcow2.c b/block/qcow2.c
index 5e5f4132d9..fe915681b2 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -272,6 +272,37 @@ static int qcow2_mark_clean(BlockDriverState *bs)
     return 0;
 }
 
+/*
+ * Marks the image as corrupt.
+ */
+int qcow2_mark_corrupt(BlockDriverState *bs)
+{
+    BDRVQcowState *s = bs->opaque;
+
+    s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT;
+    return qcow2_update_header(bs);
+}
+
+/*
+ * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes
+ * before if necessary.
+ */
+int qcow2_mark_consistent(BlockDriverState *bs)
+{
+    BDRVQcowState *s = bs->opaque;
+
+    if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) {
+        int ret = bdrv_flush(bs);
+        if (ret < 0) {
+            return ret;
+        }
+
+        s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT;
+        return qcow2_update_header(bs);
+    }
+    return 0;
+}
+
 static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result,
                        BdrvCheckMode fix)
 {
@@ -402,6 +433,17 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags)
         goto fail;
     }
 
+    if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) {
+        /* Corrupt images may not be written to unless they are being repaired
+         */
+        if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) {
+            error_report("qcow2: Image is corrupt; cannot be opened "
+                    "read/write.");
+            ret = -EACCES;
+            goto fail;
+        }
+    }
+
     /* Check support for various header values */
     if (header.refcount_order != 4) {
         report_unsupported(bs, "%d bit reference counts",
@@ -1129,6 +1171,11 @@ int qcow2_update_header(BlockDriverState *bs)
             .bit  = QCOW2_INCOMPAT_DIRTY_BITNR,
             .name = "dirty bit",
         },
+        {
+            .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
+            .bit  = QCOW2_INCOMPAT_CORRUPT_BITNR,
+            .name = "corrupt bit",
+        },
         {
             .type = QCOW2_FEAT_TYPE_COMPATIBLE,
             .bit  = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
diff --git a/block/qcow2.h b/block/qcow2.h
index 365a17e4e8..32ecb338ab 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -119,9 +119,12 @@ enum {
 /* Incompatible feature bits */
 enum {
     QCOW2_INCOMPAT_DIRTY_BITNR   = 0,
+    QCOW2_INCOMPAT_CORRUPT_BITNR = 1,
     QCOW2_INCOMPAT_DIRTY         = 1 << QCOW2_INCOMPAT_DIRTY_BITNR,
+    QCOW2_INCOMPAT_CORRUPT       = 1 << QCOW2_INCOMPAT_CORRUPT_BITNR,
 
-    QCOW2_INCOMPAT_MASK          = QCOW2_INCOMPAT_DIRTY,
+    QCOW2_INCOMPAT_MASK          = QCOW2_INCOMPAT_DIRTY
+                                 | QCOW2_INCOMPAT_CORRUPT,
 };
 
 /* Compatible feature bits */
@@ -361,6 +364,8 @@ int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
                   int64_t sector_num, int nb_sectors);
 
 int qcow2_mark_dirty(BlockDriverState *bs);
+int qcow2_mark_corrupt(BlockDriverState *bs);
+int qcow2_mark_consistent(BlockDriverState *bs);
 int qcow2_update_header(BlockDriverState *bs);
 
 /* qcow2-refcount.c functions */
diff --git a/docs/specs/qcow2.txt b/docs/specs/qcow2.txt
index 36a559d886..33eca360cc 100644
--- a/docs/specs/qcow2.txt
+++ b/docs/specs/qcow2.txt
@@ -80,7 +80,12 @@ in the description of a field.
                                 tables to repair refcounts before accessing the
                                 image.
 
-                    Bits 1-63:  Reserved (set to 0)
+                    Bit 1:      Corrupt bit.  If this bit is set then any data
+                                structure may be corrupt and the image must not
+                                be written to (unless for regaining
+                                consistency).
+
+                    Bits 2-63:  Reserved (set to 0)
 
          80 -  87:  compatible_features
                     Bitmask of compatible features. An implementation can
diff --git a/tests/qemu-iotests/031.out b/tests/qemu-iotests/031.out
index 796c993df2..a94334478e 100644
--- a/tests/qemu-iotests/031.out
+++ b/tests/qemu-iotests/031.out
@@ -54,7 +54,7 @@ header_length             72
 
 Header extension:
 magic                     0x6803f857
-length                    96
+length                    144
 data                      <binary>
 
 Header extension:
@@ -68,7 +68,7 @@ No errors were found on the image.
 
 magic                     0x514649fb
 version                   2
-backing_file_offset       0xf8
+backing_file_offset       0x128
 backing_file_size         0x17
 cluster_bits              16
 size                      67108864
@@ -92,7 +92,7 @@ data                      'host_device'
 
 Header extension:
 magic                     0x6803f857
-length                    96
+length                    144
 data                      <binary>
 
 Header extension:
@@ -155,7 +155,7 @@ header_length             104
 
 Header extension:
 magic                     0x6803f857
-length                    96
+length                    144
 data                      <binary>
 
 Header extension:
@@ -169,7 +169,7 @@ No errors were found on the image.
 
 magic                     0x514649fb
 version                   3
-backing_file_offset       0x118
+backing_file_offset       0x148
 backing_file_size         0x17
 cluster_bits              16
 size                      67108864
@@ -193,7 +193,7 @@ data                      'host_device'
 
 Header extension:
 magic                     0x6803f857
-length                    96
+length                    144
 data                      <binary>
 
 Header extension:
diff --git a/tests/qemu-iotests/036.out b/tests/qemu-iotests/036.out
index 063ca22d66..55a3e6e441 100644
--- a/tests/qemu-iotests/036.out
+++ b/tests/qemu-iotests/036.out
@@ -46,7 +46,7 @@ header_length             104
 
 Header extension:
 magic                     0x6803f857
-length                    96
+length                    144
 data                      <binary>
 
 *** done