From 0e79ef6691f77a7c0da31dff9276b6dad42441a0 Mon Sep 17 00:00:00 2001

From: Max Reitz <mreitz@redhat.com>

Date: Mon, 4 Nov 2013 22:31:59 +0100

Subject: [PATCH 06/87] qcow2: Add corrupt bit

RH-Author: Max Reitz <mreitz@redhat.com>

Message-id: <1383604354-12743-9-git-send-email-mreitz@redhat.com>

Patchwork-id: 55308

O-Subject: [RHEL-7.0 qemu-kvm PATCH 08/43] qcow2: Add corrupt bit

Bugzilla: 1004347

RH-Acked-by: Kevin Wolf <kwolf@redhat.com>

RH-Acked-by: Laszlo Ersek <lersek@redhat.com>

RH-Acked-by: Fam Zheng <famz@redhat.com>

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

BZ: 1004347

This adds an incompatible bit indicating corruption to qcow2. Any image

with this bit set may not be written to unless for repairing (and

subsequently clearing the bit if the repair has been successful).

Signed-off-by: Max Reitz <mreitz@redhat.com>

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

(cherry picked from commit 69c98726537627e708abb8fcb33e3a2b10e40bf1)

Signed-off-by: Max Reitz <mreitz@redhat.com>

---

 block/qcow2.c              | 47 ++++++++++++++++++++++++++++++++++++++++++++++

 block/qcow2.h              |  7 ++++++-

 docs/specs/qcow2.txt       |  7 ++++++-

 tests/qemu-iotests/031.out | 12 ++++++------

 tests/qemu-iotests/036.out |  2 +-

 5 files changed, 66 insertions(+), 9 deletions(-)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 block/qcow2.c              |   47 ++++++++++++++++++++++++++++++++++++++++++++

 block/qcow2.h              |    7 +++++-

 docs/specs/qcow2.txt       |    7 +++++-

 tests/qemu-iotests/031.out |   12 +++++-----

 tests/qemu-iotests/036.out |    2 +-

 5 files changed, 66 insertions(+), 9 deletions(-)

diff --git a/block/qcow2.c b/block/qcow2.c

index c2728c9..aa9dd23 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",

@@ -1140,6 +1182,11 @@ int qcow2_update_header(BlockDriverState *bs)

             .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,

             .name = "lazy refcounts",

diff --git a/block/qcow2.h b/block/qcow2.h

index dba9771..4297487 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 36a559d..33eca36 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 796c993..a943344 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 063ca22..55a3e6e 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

-- 

1.7.1