block: Use bdrv_refresh_filename() to pull
Before this patch, bdrv_refresh_filename() is used in a pushing manner:
Whenever the BDS graph is modified, the parents of the modified edges
are supposed to be updated (recursively upwards). However, that is
nonviable, considering that we want child changes not to concern
parents.
Also, in the long run we want a pull model anyway: Here, we would have a
bdrv_filename() function which returns a BDS's filename, freshly
constructed.
This patch is an intermediate step. It adds bdrv_refresh_filename()
calls before every place a BDS.filename value is used. The only
exceptions are protocol drivers that use their own filename, which
clearly would not profit from refreshing that filename before.
Also, bdrv_get_encrypted_filename() is removed along the way (as a user
of BDS.filename), since it is completely unused.
In turn, all of the calls to bdrv_refresh_filename() before this patch
are removed, because we no longer have to call this function on graph
changes.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190201192935.18394-2-mreitz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
diff --git a/blockdev.c b/blockdev.c
index 8714ad2..7e6bf99 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1627,6 +1627,7 @@
error_setg_errno(errp, -size, "bdrv_getlength failed");
goto out;
}
+ bdrv_refresh_filename(state->old_bs);
bdrv_img_create(new_image_file, format,
state->old_bs->filename,
state->old_bs->drv->format_name,
@@ -3230,6 +3231,7 @@
goto out;
}
assert(bdrv_get_aio_context(base_bs) == aio_context);
+ bdrv_refresh_filename(base_bs);
base_name = base_bs->filename;
}
@@ -3349,6 +3351,10 @@
goto out;
}
} else if (has_top && top) {
+ /* This strcmp() is just a shortcut, there is no need to
+ * refresh @bs's filename. If it mismatches,
+ * bdrv_find_backing_image() will do the refresh and may still
+ * return @bs. */
if (strcmp(bs->filename, top) != 0) {
top_bs = bdrv_find_backing_image(bs, top);
}
@@ -3509,6 +3515,7 @@
if (backup->mode != NEW_IMAGE_MODE_EXISTING) {
assert(backup->format);
if (source) {
+ bdrv_refresh_filename(source);
bdrv_img_create(backup->target, backup->format, source->filename,
source->drv->format_name, NULL,
size, flags, false, &local_err);
@@ -3889,6 +3896,7 @@
break;
case NEW_IMAGE_MODE_ABSOLUTE_PATHS:
/* create new image with backing file */
+ bdrv_refresh_filename(source);
bdrv_img_create(arg->target, format,
source->filename,
source->drv->format_name,
