From 735513ff089e56379c2cfd290c5b3e1f1a13cbcc Mon Sep 17 00:00:00 2001

From: Max Reitz <mreitz@redhat.com>

Date: Sat, 13 Jun 2015 16:22:12 +0200

Subject: [PATCH 18/42] qcow2: Split qcow2_check_refcounts()

MIME-Version: 1.0

Content-Type: text/plain; charset=UTF-8

Content-Transfer-Encoding: 8bit

Message-id: <1434212556-3927-19-git-send-email-mreitz@redhat.com>

Patchwork-id: 66037

O-Subject: [RHEL-7.2 qemu-kvm PATCH 18/42] qcow2: Split qcow2_check_refcounts()

Bugzilla: 1129893

RH-Acked-by: Jeffrey Cody <jcody@redhat.com>

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

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

BZ: 1129893

Put the code for calculating the reference counts and comparing them

during qemu-img check into own functions.

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

Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>

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

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

(cherry picked from commit 6ca56bf5e90aa167395727667d17c699950c545c)

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

Conflicts:

	block/qcow2-refcount.c

5839e53bbc0fec56021d758aab7610df421ed8c8 is missing downstream, which

replaces g*_malloc*() by g*_new*() and g*_realloc() by g*_renew() all

over the code base. Not backporting that commit results in only two

conflicts which are trivial to resolve; backporting it would mean

touching the whole code base, which I think is worse.

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

---

 block/qcow2-refcount.c | 151 +++++++++++++++++++++++++++++++++----------------

 1 file changed, 103 insertions(+), 48 deletions(-)

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

index 0c5a6ad..08b2b62 100644

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

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

@@ -1501,67 +1501,70 @@ fail:

     return new_offset;

 }

+static int check_refblocks(BlockDriverState *bs, BdrvCheckResult *res,

+                           BdrvCheckMode fix, uint16_t **refcount_table,

+                           int64_t *nb_clusters);

+

 /*

- * Checks an image for refcount consistency.

- *

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

- * detected as corrupted, and -errno when an internal error occurred.

+ * Calculates an in-memory refcount table.

  */

-int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,

-                          BdrvCheckMode fix)

+static int calculate_refcounts(BlockDriverState *bs, BdrvCheckResult *res,

+                               BdrvCheckMode fix, uint16_t **refcount_table,

+                               int64_t *nb_clusters)

 {

     BDRVQcowState *s = bs->opaque;

-    int64_t size, i, highest_cluster, nb_clusters;

-    int refcount1, refcount2;

+    int64_t i;

     QCowSnapshot *sn;

-    uint16_t *refcount_table;

     int ret;

-    size = bdrv_getlength(bs->file);

-    if (size < 0) {

+    *refcount_table = g_try_new0(uint16_t, *nb_clusters);

+    if (*nb_clusters && *refcount_table == NULL) {

         res->check_errors++;

-        return size;

+        return -ENOMEM;

     }

-    nb_clusters = size_to_clusters(s, size);

-    if (nb_clusters > INT_MAX) {

-        res->check_errors++;

-        return -EFBIG;

-    }

-

-    refcount_table = g_malloc0(nb_clusters * sizeof(uint16_t));

-

-    res->bfi.total_clusters =

-        size_to_clusters(s, bs->total_sectors * BDRV_SECTOR_SIZE);

-

     /* header */

-    inc_refcounts(bs, res, refcount_table, nb_clusters,

+    inc_refcounts(bs, res, *refcount_table, *nb_clusters,

         0, s->cluster_size);

     /* current L1 table */

-    ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters,

+    ret = check_refcounts_l1(bs, res, *refcount_table, *nb_clusters,

                              s->l1_table_offset, s->l1_size, CHECK_FRAG_INFO);

     if (ret < 0) {

-        goto fail;

+        return ret;

     }

     /* snapshots */

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

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

         sn = s->snapshots + i;

-        ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters,

+        ret = check_refcounts_l1(bs, res, *refcount_table, *nb_clusters,

             sn->l1_table_offset, sn->l1_size, 0);

         if (ret < 0) {

-            goto fail;

+            return ret;

         }

     }

-    inc_refcounts(bs, res, refcount_table, nb_clusters,

+    inc_refcounts(bs, res, *refcount_table, *nb_clusters,

         s->snapshots_offset, s->snapshots_size);

     /* refcount data */

-    inc_refcounts(bs, res, refcount_table, nb_clusters,

+    inc_refcounts(bs, res, *refcount_table, *nb_clusters,

         s->refcount_table_offset,

         s->refcount_table_size * sizeof(uint64_t));

+    return check_refblocks(bs, res, fix, refcount_table, nb_clusters);

+}

+

+/*

+ * Checks consistency of refblocks and accounts for each refblock in

+ * *refcount_table.

+ */

+static int check_refblocks(BlockDriverState *bs, BdrvCheckResult *res,

+                           BdrvCheckMode fix, uint16_t **refcount_table,

+                           int64_t *nb_clusters)

+{

+    BDRVQcowState *s = bs->opaque;

+    int64_t i;

+

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

         uint64_t offset, cluster;

         offset = s->refcount_table[i];

@@ -1575,7 +1578,7 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,

             continue;

         }

-        if (cluster >= nb_clusters) {

+        if (cluster >= *nb_clusters) {

             fprintf(stderr, "ERROR refcount block %" PRId64

                     " is outside image\n", i);

             res->corruptions++;

@@ -1583,14 +1586,14 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,

         }

         if (offset != 0) {

-            inc_refcounts(bs, res, refcount_table, nb_clusters,

+            inc_refcounts(bs, res, *refcount_table, *nb_clusters,

                 offset, s->cluster_size);

-            if (refcount_table[cluster] != 1) {

+            if ((*refcount_table)[cluster] != 1) {

                 fprintf(stderr, "%s refcount block %" PRId64

                     " refcount=%d\n",

                     fix & BDRV_FIX_ERRORS ? "Repairing" :

                                             "ERROR",

-                    i, refcount_table[cluster]);

+                    i, (*refcount_table)[cluster]);

                 if (fix & BDRV_FIX_ERRORS) {

                     int64_t new_offset;

@@ -1602,17 +1605,18 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,

                     }

                     /* update refcounts */

-                    if ((new_offset >> s->cluster_bits) >= nb_clusters) {

+                    if ((new_offset >> s->cluster_bits) >= *nb_clusters) {

                         /* increase refcount_table size if necessary */

-                        int old_nb_clusters = nb_clusters;

-                        nb_clusters = (new_offset >> s->cluster_bits) + 1;

-                        refcount_table = g_realloc(refcount_table,

-                                nb_clusters * sizeof(uint16_t));

-                        memset(&refcount_table[old_nb_clusters], 0, (nb_clusters

-                                - old_nb_clusters) * sizeof(uint16_t));

+                        int old_nb_clusters = *nb_clusters;

+                        *nb_clusters = (new_offset >> s->cluster_bits) + 1;

+                        *refcount_table = g_renew(uint16_t, *refcount_table,

+                                                  *nb_clusters);

+                        memset(&(*refcount_table)[old_nb_clusters], 0,

+                               (*nb_clusters - old_nb_clusters) *

+                               sizeof(uint16_t));

                     }

-                    refcount_table[cluster]--;

-                    inc_refcounts(bs, res, refcount_table, nb_clusters,

+                    (*refcount_table)[cluster]--;

+                    inc_refcounts(bs, res, *refcount_table, *nb_clusters,

                             new_offset, s->cluster_size);

                     res->corruptions_fixed++;

@@ -1623,8 +1627,22 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,

         }

     }

-    /* compare ref counts */

-    for (i = 0, highest_cluster = 0; i < nb_clusters; i++) {

+    return 0;

+}

+

+/*

+ * Compares the actual reference count for each cluster in the image against the

+ * refcount as reported by the refcount structures on-disk.

+ */

+static void compare_refcounts(BlockDriverState *bs, BdrvCheckResult *res,

+                              BdrvCheckMode fix, int64_t *highest_cluster,

+                              uint16_t *refcount_table, int64_t nb_clusters)

+{

+    BDRVQcowState *s = bs->opaque;

+    int64_t i;

+    int refcount1, refcount2, ret;

+

+    for (i = 0, *highest_cluster = 0; i < nb_clusters; i++) {

         refcount1 = get_refcount(bs, i);

         if (refcount1 < 0) {

             fprintf(stderr, "Can't get refcount for cluster %" PRId64 ": %s\n",

@@ -1636,11 +1654,10 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,

         refcount2 = refcount_table[i];

         if (refcount1 > 0 || refcount2 > 0) {

-            highest_cluster = i;

+            *highest_cluster = i;

         }

         if (refcount1 != refcount2) {

-

             /* Check if we're allowed to fix the mismatch */

             int *num_fixed = NULL;

             if (refcount1 > refcount2 && (fix & BDRV_FIX_LEAKS)) {

@@ -1673,6 +1690,44 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,

             }

         }

     }

+}

+

+/*

+ * Checks an image for refcount consistency.

+ *

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

+ * detected as corrupted, and -errno when an internal error occurred.

+ */

+int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,

+                          BdrvCheckMode fix)

+{

+    BDRVQcowState *s = bs->opaque;

+    int64_t size, highest_cluster, nb_clusters;

+    uint16_t *refcount_table;

+    int ret;

+

+    size = bdrv_getlength(bs->file);

+    if (size < 0) {

+        res->check_errors++;

+        return size;

+    }

+

+    nb_clusters = size_to_clusters(s, size);

+    if (nb_clusters > INT_MAX) {

+        res->check_errors++;

+        return -EFBIG;

+    }

+

+    res->bfi.total_clusters =

+        size_to_clusters(s, bs->total_sectors * BDRV_SECTOR_SIZE);

+

+    ret = calculate_refcounts(bs, res, fix, &refcount_table, &nb_clusters);

+    if (ret < 0) {

+        goto fail;

+    }

+

+    compare_refcounts(bs, res, fix, &highest_cluster, refcount_table,

+                      nb_clusters);

     /* check OFLAG_COPIED */

     ret = check_oflag_copied(bs, res, fix);

-- 

1.8.3.1