block: Deprecate bdrv_set_read_only() and users

bdrv_set_read_only() is used by some block drivers to override the
read-only option given by the user. This is not how read-only images
generally work in QEMU: Instead of second guessing what the user really
meant (which currently includes making an image read-only even if the
user didn't only use the default, but explicitly said read-only=off), we
should error out if we can't provide what the user requested.

This adds deprecation warnings to all callers of bdrv_set_read_only() so
that the behaviour can be corrected after the usual deprecation period.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2017-11-07 18:21:41 +01:00
parent f66afbe26f
commit 398e6ad014
7 changed files with 54 additions and 16 deletions

View file

@ -665,10 +665,16 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags,
/* If we are using an rbd snapshot, we must be r/o, otherwise
* leave as-is */
if (s->snap != NULL) {
r = bdrv_set_read_only(bs, true, &local_err);
if (r < 0) {
error_propagate(errp, local_err);
goto failed_open;
if (!bdrv_is_read_only(bs)) {
error_report("Opening rbd snapshots without an explicit "
"read-only=on option is deprecated. Future versions "
"will refuse to open the image instead of "
"automatically marking the image read-only.");
r = bdrv_set_read_only(bs, true, &local_err);
if (r < 0) {
error_propagate(errp, local_err);
goto failed_open;
}
}
}