From: Hanna Reitz <hre...@redhat.com>
Just like qcow2, qed invokes its open function in its
.bdrv_co_invalidate_cache() implementation. Therefore, just like done
for qcow2 in HEAD^, update auto_backing_file only if the backing file
string in the image header differs from the one we have read before.
Signed-off-by: Hanna Reitz <hre...@redhat.com>
Message-Id: <20220803144446.20723-3-hre...@redhat.com>
Reviewed-by: Kevin Wolf <kw...@redhat.com>
Signed-off-by: Kevin Wolf <kw...@redhat.com>
---
block/qed.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/block/qed.c b/block/qed.c
index 40943e679b..324ca0e95a 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -445,6 +445,8 @@ static int coroutine_fn bdrv_qed_do_open(BlockDriverState
*bs, QDict *options,
}
if ((s->header.features & QED_F_BACKING_FILE)) {
+ g_autofree char *backing_file_str = NULL;
+
if ((uint64_t)s->header.backing_filename_offset +
s->header.backing_filename_size >
s->header.cluster_size * s->header.header_size) {
@@ -452,16 +454,21 @@ static int coroutine_fn bdrv_qed_do_open(BlockDriverState
*bs, QDict *options,
return -EINVAL;
}
+ backing_file_str = g_malloc(sizeof(bs->backing_file));
ret = qed_read_string(bs->file, s->header.backing_filename_offset,
s->header.backing_filename_size,
- bs->auto_backing_file,
- sizeof(bs->auto_backing_file));
+ backing_file_str, sizeof(bs->backing_file));
if (ret < 0) {
error_setg(errp, "Failed to read backing filename");
return ret;
}
- pstrcpy(bs->backing_file, sizeof(bs->backing_file),
- bs->auto_backing_file);
+
+ if (!g_str_equal(backing_file_str, bs->backing_file)) {
+ pstrcpy(bs->backing_file, sizeof(bs->backing_file),
+ backing_file_str);
+ pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file),
+ backing_file_str);
+ }
if (s->header.features & QED_F_BACKING_FORMAT_NO_PROBE) {
pstrcpy(bs->backing_format, sizeof(bs->backing_format), "raw");
--
2.37.3
