[Qemu-devel] [PATCH v2] block: fix vvfat error path for enable_write_target

[Qemu-devel] [PATCH v2] block: fix vvfat error path for enable_write_target

[Fam Zheng]

s->qcow and s->qcow_filename are allocated but not freed on error. Fix the
possible leaks, remove unnecessary check for bdrv_new(), propagate ret code of
bdrv_create() and also the one of enable_write_target().

Signed-off-by: Fam Zheng <famz@redhat.com>
---

v2: Fix leak of s->qcow_filename, propagate returen value of
    enable_write_target(). [Laszlo]

---
 block/vvfat.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/block/vvfat.c b/block/vvfat.c
index 87b0279..cd3b8ed 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -1164,8 +1164,8 @@ DLOG(if (stderr == NULL) {
     s->sector_count = cyls * heads * secs - (s->first_sectors_number - 1);
 
     if (qemu_opt_get_bool(opts, "rw", false)) {
-        if (enable_write_target(s)) {
-            ret = -EIO;
+        ret = enable_write_target(s);
+        if (ret < 0) {
             goto fail;
         }
         bs->read_only = 0;
@@ -2917,9 +2917,7 @@ static int enable_write_target(BDRVVVFATState *s)
     s->qcow_filename = g_malloc(1024);
     ret = get_tmp_filename(s->qcow_filename, 1024);
     if (ret < 0) {
-        g_free(s->qcow_filename);
-        s->qcow_filename = NULL;
-        return ret;
+        goto err;
     }
 
     bdrv_qcow = bdrv_find_format("qcow");
@@ -2927,18 +2925,18 @@ static int enable_write_target(BDRVVVFATState *s)
     set_option_parameter_int(options, BLOCK_OPT_SIZE, s->sector_count * 512);
     set_option_parameter(options, BLOCK_OPT_BACKING_FILE, "fat:");
 
-    if (bdrv_create(bdrv_qcow, s->qcow_filename, options) < 0)
-	return -1;
+    ret = bdrv_create(bdrv_qcow, s->qcow_filename, options);
+    if (ret < 0) {
+        goto err;
+    }
 
     s->qcow = bdrv_new("");
-    if (s->qcow == NULL) {
-        return -1;
-    }
 
     ret = bdrv_open(s->qcow, s->qcow_filename, NULL,
             BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH, bdrv_qcow);
     if (ret < 0) {
-	return ret;
+        bdrv_delete(s->qcow);
+        goto err;
     }
 
 #ifndef _WIN32
@@ -2951,6 +2949,11 @@ static int enable_write_target(BDRVVVFATState *s)
     *(void**)s->bs->backing_hd->opaque = s;
 
     return 0;
+
+err:
+    g_free(s->qcow_filename);
+    s->qcow_filename = NULL;
+    return ret;
 }
 
 static void vvfat_close(BlockDriverState *bs)
-- 
1.8.3.2

Re: [Qemu-devel] [PATCH v2] block: fix vvfat error path for enable_write_target

[Laszlo Ersek]

On 07/17/13 11:57, Fam Zheng wrote:
> s->qcow and s->qcow_filename are allocated but not freed on error. Fix the
> possible leaks, remove unnecessary check for bdrv_new(), propagate ret code of
> bdrv_create() and also the one of enable_write_target().
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
> 
> v2: Fix leak of s->qcow_filename, propagate returen value of
>     enable_write_target(). [Laszlo]
> 
> ---
>  block/vvfat.c | 25 ++++++++++++++-----------
>  1 file changed, 14 insertions(+), 11 deletions(-)

Looks good to me.

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

Re: [Qemu-devel] [PATCH v2] block: fix vvfat error path for enable_write_target

[Stefan Hajnoczi]

On Wed, Jul 17, 2013 at 05:57:37PM +0800, Fam Zheng wrote:
> s->qcow and s->qcow_filename are allocated but not freed on error. Fix the
> possible leaks, remove unnecessary check for bdrv_new(), propagate ret code of
> bdrv_create() and also the one of enable_write_target().
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
> 
> v2: Fix leak of s->qcow_filename, propagate returen value of
>     enable_write_target(). [Laszlo]
> 
> ---
>  block/vvfat.c | 25 ++++++++++++++-----------
>  1 file changed, 14 insertions(+), 11 deletions(-)

Thanks, applied to my block tree:
https://github.com/stefanha/qemu/commits/block

Stefan