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[Qemu-devel] [PATCH 14/19] vmdk: clean up open
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH 14/19] vmdk: clean up open |
Date: |
Fri, 21 Oct 2011 19:19:11 +0200 |
From: Paolo Bonzini <address@hidden>
Move vmdk_parent_open to vmdk_open. There's another path how
vmdk_parent_open can be reached:
vmdk_parse_extents() -> vmdk_open_sparse() -> vmdk_open_vmdk4() ->
vmdk_open_desc_file().
If that can happen, however, the code is bogus. vmdk_parent_open
reads from bs->file:
if (bdrv_pread(bs->file, s->desc_offset, desc, DESC_SIZE) != DESC_SIZE) {
but it is always called with s->desc_offset == 0 and with the same
bs->file. So the data that vmdk_parent_open reads comes always from the
same place, and anyway there is only one place where it can write it,
namely bs->backing_file.
So, if it cannot happen, the patched code is okay.
It is also possible that the recursive call can happen, but only once. In
that case there would still be a bug in vmdk_open_desc_file setting
s->desc_offset = 0, but the patched code is okay.
Finally, in the case where multiple recursive calls can happen the code
would need to be rewritten anyway. It is likely that this would anyway
involve adding several parameters to vmdk_parent_open, and calling it from
vmdk_open_vmdk4.
Signed-off-by: Paolo Bonzini <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
---
block/vmdk.c | 37 +++++++++++++++----------------------
1 files changed, 15 insertions(+), 22 deletions(-)
diff --git a/block/vmdk.c b/block/vmdk.c
index ea00938..ace2977 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -624,20 +624,7 @@ static int vmdk_open_desc_file(BlockDriverState *bs, int
flags,
return -ENOTSUP;
}
s->desc_offset = 0;
- ret = vmdk_parse_extents(buf, bs, bs->file->filename);
- if (ret) {
- vmdk_free_extents(bs);
- return ret;
- }
-
- /* try to open parent images, if exist */
- ret = vmdk_parent_open(bs);
- if (ret) {
- vmdk_free_extents(bs);
- return ret;
- }
- s->parent_cid = vmdk_read_cid(bs, 1);
- return 0;
+ return vmdk_parse_extents(buf, bs, bs->file->filename);
}
static int vmdk_open(BlockDriverState *bs, int flags)
@@ -647,17 +634,23 @@ static int vmdk_open(BlockDriverState *bs, int flags)
if (vmdk_open_sparse(bs, bs->file, flags) == 0) {
s->desc_offset = 0x200;
- /* try to open parent images, if exist */
- ret = vmdk_parent_open(bs);
+ } else {
+ ret = vmdk_open_desc_file(bs, flags, 0);
if (ret) {
- vmdk_free_extents(bs);
- return ret;
+ goto fail;
}
- s->parent_cid = vmdk_read_cid(bs, 1);
- return 0;
- } else {
- return vmdk_open_desc_file(bs, flags, 0);
}
+ /* try to open parent images, if exist */
+ ret = vmdk_parent_open(bs);
+ if (ret) {
+ goto fail;
+ }
+ s->parent_cid = vmdk_read_cid(bs, 1);
+ return ret;
+
+fail:
+ vmdk_free_extents(bs);
+ return ret;
}
static int get_whole_cluster(BlockDriverState *bs,
--
1.7.6.4
- [Qemu-devel] [PATCH 04/19] fix memory leak in aio_write_f, (continued)
- [Qemu-devel] [PATCH 04/19] fix memory leak in aio_write_f, Kevin Wolf, 2011/10/21
- [Qemu-devel] [PATCH 05/19] xen_disk: Always set feature-barrier = 1, Kevin Wolf, 2011/10/21
- [Qemu-devel] [PATCH 08/19] block: add bdrv_co_discard and bdrv_aio_discard support, Kevin Wolf, 2011/10/21
- [Qemu-devel] [PATCH 06/19] block: unify flush implementations, Kevin Wolf, 2011/10/21
- [Qemu-devel] [PATCH 10/19] qemu-img: Don't allow preallocation and compression at the same time, Kevin Wolf, 2011/10/21
- [Qemu-devel] [PATCH 09/19] fdc: Fix floppy port I/O, Kevin Wolf, 2011/10/21
- [Qemu-devel] [PATCH 11/19] qcow2: Fix bdrv_write_compressed error handling, Kevin Wolf, 2011/10/21
- [Qemu-devel] [PATCH 07/19] block: drop redundant bdrv_flush implementation, Kevin Wolf, 2011/10/21
- [Qemu-devel] [PATCH 12/19] pc: Fix floppy drives with if=none, Kevin Wolf, 2011/10/21
- [Qemu-devel] [PATCH 17/19] block: take lock around bdrv_write implementations, Kevin Wolf, 2011/10/21
- [Qemu-devel] [PATCH 14/19] vmdk: clean up open,
Kevin Wolf <=
- [Qemu-devel] [PATCH 16/19] block: take lock around bdrv_read implementations, Kevin Wolf, 2011/10/21
- [Qemu-devel] [PATCH 13/19] vmdk: fix return values of vmdk_parent_open, Kevin Wolf, 2011/10/21
- [Qemu-devel] [PATCH 18/19] block: change flush to co_flush, Kevin Wolf, 2011/10/21
- [Qemu-devel] [PATCH 15/19] block: add a CoMutex to synchronous read drivers, Kevin Wolf, 2011/10/21
- [Qemu-devel] [PATCH 19/19] block: change discard to co_discard, Kevin Wolf, 2011/10/21
- Re: [Qemu-devel] [PULL 00/19] Block patches, Anthony Liguori, 2011/10/24