From f10d5c98b4e810975e7d922dde3b814532bb086d Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Thu, 21 Jan 2010 14:03:01 -0200
Subject: [PATCH 03/10] qcow2: Return 0/-errno in get_cluster_table

RH-Author: Kevin Wolf <kwolf@redhat.com>
Message-id: <1264082588-10273-4-git-send-email-kwolf@redhat.com>
Patchwork-id: 6512
O-Subject: [RHEL-5.5 KVM PATCH 03/10] qcow2: Return 0/-errno in get_cluster_table
Bugzilla: 537077
RH-Acked-by: Christoph Hellwig <chellwig@redhat.com>
RH-Acked-by: Juan Quintela <quintela@redhat.com>
RH-Acked-by: Gleb Natapov <gleb@redhat.com>
RH-Acked-by: Markus Armbruster <armbru@redhat.com>

Bugzilla: 537077
Upstream status: Submitted

Switching to 0/-errno allows it to distinguish different error cases.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 qemu/block-qcow2.c |   30 ++++++++++++++++++------------
 1 files changed, 18 insertions(+), 12 deletions(-)

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 qemu/block-qcow2.c |   30 ++++++++++++++++++------------
 1 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/qemu/block-qcow2.c b/qemu/block-qcow2.c
index a4e70d6..5cca34a 100644
--- a/qemu/block-qcow2.c
+++ b/qemu/block-qcow2.c
@@ -896,8 +896,8 @@ static void free_any_clusters(BlockDriverState *bs,
  * the l2 table offset in the qcow2 file and the cluster index
  * in the l2 table are given to the caller.
  *
+ * Returns 0 on success, -errno in failure case
  */
-
 static int get_cluster_table(BlockDriverState *bs, uint64_t offset,
                              uint64_t **new_l2_table,
                              uint64_t *new_l2_offset,
@@ -912,8 +912,9 @@ static int get_cluster_table(BlockDriverState *bs, uint64_t offset,
     l1_index = offset >> (s->l2_bits + s->cluster_bits);
     if (l1_index >= s->l1_size) {
         ret = grow_l1_table(bs, l1_index + 1);
-        if (ret < 0)
-            return 0;
+        if (ret < 0) {
+            return ret;
+        }
     }
     l2_offset = s->l1_table[l1_index];
 
@@ -923,14 +924,16 @@ static int get_cluster_table(BlockDriverState *bs, uint64_t offset,
         /* load the l2 table in memory */
         l2_offset &= ~QCOW_OFLAG_COPIED;
         l2_table = l2_load(bs, l2_offset);
-        if (l2_table == NULL)
-            return 0;
+        if (l2_table == NULL) {
+            return -EIO;
+        }
     } else {
         if (l2_offset)
             free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t));
         l2_table = l2_allocate(bs, l1_index);
-        if (l2_table == NULL)
-            return 0;
+        if (l2_table == NULL) {
+            return -EIO;
+        }
         l2_offset = s->l1_table[l1_index] & ~QCOW_OFLAG_COPIED;
     }
 
@@ -942,7 +945,7 @@ static int get_cluster_table(BlockDriverState *bs, uint64_t offset,
     *new_l2_offset = l2_offset;
     *new_l2_index = l2_index;
 
-    return 1;
+    return 0;
 }
 
 /*
@@ -968,8 +971,9 @@ static uint64_t alloc_compressed_cluster_offset(BlockDriverState *bs,
     int nb_csectors;
 
     ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
-    if (ret == 0)
+    if (ret < 0) {
         return 0;
+    }
 
     cluster_offset = be64_to_cpu(l2_table[l2_index]);
     if (cluster_offset & QCOW_OFLAG_COPIED)
@@ -1058,10 +1062,11 @@ static int alloc_cluster_link_l2(BlockDriverState *bs, uint64_t cluster_offset,
             goto err;
     }
 
-    ret = -EIO;
     /* update L2 table */
-    if (!get_cluster_table(bs, m->offset, &l2_table, &l2_offset, &l2_index))
+    ret = get_cluster_table(bs, m->offset, &l2_table, &l2_offset, &l2_index);
+    if (ret < 0) {
         goto err;
+    }
 
     for (i = 0; i < m->nb_clusters; i++) {
         /* if two concurrent writes happen to the same unallocated cluster
@@ -1116,8 +1121,9 @@ static uint64_t alloc_cluster_offset(BlockDriverState *bs,
     int nb_clusters, i = 0;
 
     ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
-    if (ret == 0)
+    if (ret < 0) {
         return 0;
+    }
 
     nb_clusters = size_to_clusters(s, n_end << 9);
 
-- 
1.6.3.rc4.29.g8146