From 27a96310e27b1b3880935430d58330a90ccc0176 Mon Sep 17 00:00:00 2001

From: Max Reitz <mreitz@redhat.com>

Date: Mon, 4 Nov 2013 22:32:02 +0100

Subject: [PATCH 09/87] qcow2-refcount: Move OFLAG_COPIED checks

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

Message-id: <1383604354-12743-12-git-send-email-mreitz@redhat.com>

Patchwork-id: 55311

O-Subject: [RHEL-7.0 qemu-kvm PATCH 11/43] qcow2-refcount: Move OFLAG_COPIED checks

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

Move the OFLAG_COPIED checks out of check_refcounts_l1 and

check_refcounts_l2 and after the actual refcount checks/fixes (since the

refcounts might actually change there).

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

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

(cherry picked from commit 4f6ed88c03c4026e31ce152ea760a0da839f0dda)

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

---

 block/qcow2-refcount.c | 115 +++++++++++++++++++++++++++++++++++--------------

 1 file changed, 82 insertions(+), 33 deletions(-)

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

---

 block/qcow2-refcount.c |  115 ++++++++++++++++++++++++++++++++++--------------

 1 files changed, 82 insertions(+), 33 deletions(-)

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

index 310efcc..ddc3029 100644

--- a/block/qcow2-refcount.c

+++ b/block/qcow2-refcount.c

@@ -1035,7 +1035,7 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,

     BDRVQcowState *s = bs->opaque;

     uint64_t *l2_table, l2_entry;

     uint64_t next_contiguous_offset = 0;

-    int i, l2_size, nb_csectors, refcount;

+    int i, l2_size, nb_csectors;

     /* Read L2 table from disk */

     l2_size = s->l2_size * sizeof(uint64_t);

@@ -1087,23 +1087,8 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,

         case QCOW2_CLUSTER_NORMAL:

         {

-            /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */

             uint64_t offset = l2_entry & L2E_OFFSET_MASK;

-            if (flags & CHECK_OFLAG_COPIED) {

-                refcount = get_refcount(bs, offset >> s->cluster_bits);

-                if (refcount < 0) {

-                    fprintf(stderr, "Can't get refcount for offset %"

-                        PRIx64 ": %s\n", l2_entry, strerror(-refcount));

-                    goto fail;

-                }

-                if ((refcount == 1) != ((l2_entry & QCOW_OFLAG_COPIED) != 0)) {

-                    fprintf(stderr, "ERROR OFLAG_COPIED: offset=%"

-                        PRIx64 " refcount=%d\n", l2_entry, refcount);

-                    res->corruptions++;

-                }

-            }

-

             if (flags & CHECK_FRAG_INFO) {

                 res->bfi.allocated_clusters++;

                 if (next_contiguous_offset &&

@@ -1160,7 +1145,7 @@ static int check_refcounts_l1(BlockDriverState *bs,

 {

     BDRVQcowState *s = bs->opaque;

     uint64_t *l1_table, l2_offset, l1_size2;

-    int i, refcount, ret;

+    int i, ret;

     l1_size2 = l1_size * sizeof(uint64_t);

@@ -1184,22 +1169,6 @@ static int check_refcounts_l1(BlockDriverState *bs,

     for(i = 0; i < l1_size; i++) {

         l2_offset = l1_table[i];

         if (l2_offset) {

-            /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */

-            if (flags & CHECK_OFLAG_COPIED) {

-                refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED)

-                    >> s->cluster_bits);

-                if (refcount < 0) {

-                    fprintf(stderr, "Can't get refcount for l2_offset %"

-                        PRIx64 ": %s\n", l2_offset, strerror(-refcount));

-                    goto fail;

-                }

-                if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) {

-                    fprintf(stderr, "ERROR OFLAG_COPIED: l2_offset=%" PRIx64

-                        " refcount=%d\n", l2_offset, refcount);

-                    res->corruptions++;

-                }

-            }

-

             /* Mark L2 table as used */

             l2_offset &= L1E_OFFSET_MASK;

             inc_refcounts(bs, res, refcount_table, refcount_table_size,

@@ -1231,6 +1200,80 @@ fail:

 }

 /*

+ * Checks the OFLAG_COPIED flag for all L1 and L2 entries.

+ *

+ * This function does not print an error message nor does it increment

+ * check_errors if get_refcount fails (this is because such an error will have

+ * been already detected and sufficiently signaled by the calling function

+ * (qcow2_check_refcounts) by the time this function is called).

+ */

+static int check_oflag_copied(BlockDriverState *bs, BdrvCheckResult *res)

+{

+    BDRVQcowState *s = bs->opaque;

+    uint64_t *l2_table = qemu_blockalign(bs, s->cluster_size);

+    int ret;

+    int refcount;

+    int i, j;

+

+    for (i = 0; i < s->l1_size; i++) {

+        uint64_t l1_entry = s->l1_table[i];

+        uint64_t l2_offset = l1_entry & L1E_OFFSET_MASK;

+

+        if (!l2_offset) {

+            continue;

+        }

+

+        refcount = get_refcount(bs, l2_offset >> s->cluster_bits);

+        if (refcount < 0) {

+            /* don't print message nor increment check_errors */

+            continue;

+        }

+        if ((refcount == 1) != ((l1_entry & QCOW_OFLAG_COPIED) != 0)) {

+            fprintf(stderr, "ERROR OFLAG_COPIED L2 cluster: l1_index=%d "

+                    "l1_entry=%" PRIx64 " refcount=%d\n",

+                    i, l1_entry, refcount);

+            res->corruptions++;

+        }

+

+        ret = bdrv_pread(bs->file, l2_offset, l2_table,

+                         s->l2_size * sizeof(uint64_t));

+        if (ret < 0) {

+            fprintf(stderr, "ERROR: Could not read L2 table: %s\n",

+                    strerror(-ret));

+            res->check_errors++;

+            goto fail;

+        }

+

+        for (j = 0; j < s->l2_size; j++) {

+            uint64_t l2_entry = be64_to_cpu(l2_table[j]);

+            uint64_t data_offset = l2_entry & L2E_OFFSET_MASK;

+            int cluster_type = qcow2_get_cluster_type(l2_entry);

+

+            if ((cluster_type == QCOW2_CLUSTER_NORMAL) ||

+                ((cluster_type == QCOW2_CLUSTER_ZERO) && (data_offset != 0))) {

+                refcount = get_refcount(bs, data_offset >> s->cluster_bits);

+                if (refcount < 0) {

+                    /* don't print message nor increment check_errors */

+                    continue;

+                }

+                if ((refcount == 1) != ((l2_entry & QCOW_OFLAG_COPIED) != 0)) {

+                    fprintf(stderr, "ERROR OFLAG_COPIED data cluster: "

+                            "l2_entry=%" PRIx64 " refcount=%d\n",

+                            l2_entry, refcount);

+                    res->corruptions++;

+                }

+            }

+        }

+    }

+

+    ret = 0;

+

+fail:

+    qemu_vfree(l2_table);

+    return ret;

+}

+

+/*

  * Checks an image for refcount consistency.

  *

  * Returns 0 if no errors are found, the number of errors in case the image is

@@ -1365,6 +1408,12 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,

         }

     }

+    /* check OFLAG_COPIED */

+    ret = check_oflag_copied(bs, res);

+    if (ret < 0) {

+        goto fail;

+    }

+

     res->image_end_offset = (highest_cluster + 1) * s->cluster_size;

     ret = 0;

-- 

1.7.1