From d306fd5f4ad5f0f168271a77d114931db7a337ea Mon Sep 17 00:00:00 2001
From: Fam Zheng <famz@redhat.com>
Date: Wed, 26 Jun 2013 17:24:32 +0800
Subject: [PATCH] vmdk: remove wrong calculation of relative path

When creating image with backing file, the driver tries to calculate the
relative path from created image file to backing file, but the path
computation is incorrect. e.g.:

    $ qemu-img create -f vmdk -b vmdk-data-disk.vmdk vmdk-data-snapshot1
    Formatting 'vmdk-data-snapshot1', fmt=vmdk size=10737418240
    backing_file='vmdk-data-disk.vmdk' compat6=off zeroed_grain=off

    $ qemu-img info vmdk-data-snapshot1
    image: vmdk-data-snapshot1
    file format: vmdk
    virtual size: 10G (10737418240 bytes)
    disk size: 12K
->  backing file: disk.vmdk

The common part in file names, "vmdk-data-", is incorrectly forgotten by
relative_path(). As the VMDK specification has no restriction on
parentNameHint to be relative path, we simply remove this by using the
backing_file option.

Cc: qemu-stable@nongnu.org
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 8ed610a1c983dd2ed1eed8841036af55751d115f)

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 block/vmdk.c | 44 +-------------------------------------------
 1 file changed, 1 insertion(+), 43 deletions(-)

diff --git a/block/vmdk.c b/block/vmdk.c
index ee50a737c1..8c8f1fd4f4 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -1465,45 +1465,6 @@ static int filename_decompose(const char *filename, char *path, char *prefix,
     return VMDK_OK;
 }
 
-static int relative_path(char *dest, int dest_size,
-        const char *base, const char *target)
-{
-    int i = 0;
-    int n = 0;
-    const char *p, *q;
-#ifdef _WIN32
-    const char *sep = "\\";
-#else
-    const char *sep = "/";
-#endif
-
-    if (!(dest && base && target)) {
-        return VMDK_ERROR;
-    }
-    if (path_is_absolute(target)) {
-        pstrcpy(dest, dest_size, target);
-        return VMDK_OK;
-    }
-    while (base[i] == target[i]) {
-        i++;
-    }
-    p = &base[i];
-    q = &target[i];
-    while (*p) {
-        if (*p == *sep) {
-            n++;
-        }
-        p++;
-    }
-    dest[0] = '\0';
-    for (; n; n--) {
-        pstrcat(dest, dest_size, "..");
-        pstrcat(dest, dest_size, sep);
-    }
-    pstrcat(dest, dest_size, q);
-    return VMDK_OK;
-}
-
 static int vmdk_create(const char *filename, QEMUOptionParameter *options)
 {
     int fd, idx = 0;
@@ -1603,7 +1564,6 @@ static int vmdk_create(const char *filename, QEMUOptionParameter *options)
         return -ENOTSUP;
     }
     if (backing_file) {
-        char parent_filename[PATH_MAX];
         BlockDriverState *bs = bdrv_new("");
         ret = bdrv_open(bs, backing_file, NULL, 0, NULL);
         if (ret != 0) {
@@ -1616,10 +1576,8 @@ static int vmdk_create(const char *filename, QEMUOptionParameter *options)
         }
         parent_cid = vmdk_read_cid(bs, 0);
         bdrv_delete(bs);
-        relative_path(parent_filename, sizeof(parent_filename),
-                      filename, backing_file);
         snprintf(parent_desc_line, sizeof(parent_desc_line),
-                "parentFileNameHint=\"%s\"", parent_filename);
+                "parentFileNameHint=\"%s\"", backing_file);
     }
 
     /* Create extents */
-- 
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