drive-backup argument @format defaults to the format of the source
unless @mode is "existing".
drive_backup_prepare() implements this by copying the source's
@format_name to DriveBackup member @format. It leaves @has_format
false, violating the "has_format == !!format" invariant. Unclean.
Falls apart when we elide @has_format (commit after next): then QAPI
passes @format, which is a string constant, to g_free(). iotest 056
duly explodes.
Clean it up. Since the value stored in member @format is not actually
used outside this function, use a local variable instead of modifying
the QAPI object.
Signed-off-by: Markus Armbruster <arm...@redhat.com>
Cc: Kevin Wolf <kw...@redhat.com>
Cc: Hanna Reitz <hre...@redhat.com>
Cc: qemu-bl...@nongnu.org
Message-Id: <20221104160712.3005652-9-arm...@redhat.com>
Reviewed-by: Eric Blake <ebl...@redhat.com>
---
blockdev.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/blockdev.c b/blockdev.c
index 3f1dec6242..d6550e0dc8 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1686,6 +1686,7 @@ static void drive_backup_prepare(BlkActionState *common,
Error **errp)
BlockDriverState *source = NULL;
AioContext *aio_context;
AioContext *old_context;
+ const char *format;
QDict *options;
Error *local_err = NULL;
int flags;
@@ -1717,9 +1718,9 @@ static void drive_backup_prepare(BlkActionState *common,
Error **errp)
/* Paired with .clean() */
bdrv_drained_begin(bs);
- if (!backup->has_format) {
- backup->format = backup->mode == NEW_IMAGE_MODE_EXISTING ?
- NULL : (char *) bs->drv->format_name;
+ format = backup->format;
+ if (!format && backup->mode != NEW_IMAGE_MODE_EXISTING) {
+ format = bs->drv->format_name;
}
/* Early check to avoid creating target */
@@ -1758,19 +1759,19 @@ static void drive_backup_prepare(BlkActionState
*common, Error **errp)
}
if (backup->mode != NEW_IMAGE_MODE_EXISTING) {
- assert(backup->format);
+ assert(format);
if (source) {
/* Implicit filters should not appear in the filename */
BlockDriverState *explicit_backing =
bdrv_skip_implicit_filters(source);
bdrv_refresh_filename(explicit_backing);
- bdrv_img_create(backup->target, backup->format,
+ bdrv_img_create(backup->target, format,
explicit_backing->filename,
explicit_backing->drv->format_name, NULL,
size, flags, false, &local_err);
} else {
- bdrv_img_create(backup->target, backup->format, NULL, NULL, NULL,
+ bdrv_img_create(backup->target, format, NULL, NULL, NULL,
size, flags, false, &local_err);
}
}
@@ -1783,8 +1784,8 @@ static void drive_backup_prepare(BlkActionState *common,
Error **errp)
options = qdict_new();
qdict_put_str(options, "discard", "unmap");
qdict_put_str(options, "detect-zeroes", "unmap");
- if (backup->format) {
- qdict_put_str(options, "driver", backup->format);
+ if (format) {
+ qdict_put_str(options, "driver", format);
}
target_bs = bdrv_open(backup->target, NULL, options, flags, errp);
--
2.37.3
