Re: [Qemu-devel] [PATCH V4 3/6] qcow2: do not free clusters when fail in header update in qcow2_write_snapshots

[Wenchao Xia]

于 2013/11/2 21:56, Max Reitz 写道:

On 02.11.2013 14:04, Max Reitz wrote:

On 14.10.2013 23:52, Wenchao Xia wrote:

Signed-off-by: Wenchao Xia <xiaw...@linux.vnet.ibm.com>
---
  block/qcow2-snapshot.c |    7 +++++++
  1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index 4bd494b..c933b7f 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -304,6 +304,13 @@ static int qcow2_write_snapshots(BlockDriverState *bs, 
Error **errp)
                     PRIi64 " with size %" PRIu64 ":%d (%s)",
                     offsetof(QCowHeader, nb_snapshots), sizeof(header_data),
                     ret, strerror(-ret));
+        /*
+         * If the snapshot data part have been updated on disk, Then the

s/have/has/; s/Then/then/

+         * clusters at snapshot_offset may be used in next snapshot operation.
+         * If we free those clusters in fail path, they may be allocated and
+         * made dirty causing damage, so skip cluster free for safe.

s/for/to be/

+         */
+        snapshots_offset = 0;
          goto fail;
      }

Other then that: Reviewed-by: Max Reitz <mre...@redhat.com>

*than, of course; if I am already correcting other people's orthography,
I have to do the same for mine. ;-)

Max

  Thanks for reviewing, I'll fix the issues you pointed out and respin.