'discard' is one of the basic BlockdevOptions available for all
drivers, but it's silently ignored by bdrv_reopen_prepare/commit(), so
the user cannot change it and doesn't get an error explaining that it
can't be changed.
This should update the discard setting, but does nothing:
(qemu) qemu-io virtio0 "reopen -o discard=on"
Since there's no reason why we shouldn't allow changing it and the
implementation is simple let's just do it.
Signed-off-by: Alberto Garcia <be...@igalia.com>
---
block.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/block.c b/block.c
index 804d557608..21f1eb9cd1 100644
--- a/block.c
+++ b/block.c
@@ -3178,6 +3178,15 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
BlockReopenQueue *queue,
update_flags_from_options(&reopen_state->flags, opts);
+ value = qemu_opt_get(opts, "discard");
+ if (value != NULL) {
+ if (bdrv_parse_discard_flags(value, &reopen_state->flags) != 0) {
+ error_setg(errp, "Invalid discard option");
+ ret = -EINVAL;
+ goto error;
+ }
+ }
+
/* node-name and driver must be unchanged. Put them back into the QDict, so
* that they are checked at the end of this function. */
value = qemu_opt_get(opts, "node-name");
--
2.11.0
