| Message ID | 20190809161407.11920-24-mreitz@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | block: Deal with filters | expand |
Am 09.08.2019 um 18:13 hat Max Reitz geschrieben: > This allows us to differentiate between filters and nodes with COW > backing files: Filters cannot be used as overlays at all (for this > function). > > Signed-off-by: Max Reitz <mreitz@redhat.com> > Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Didn't we occasionally advertise blockdev-snapshot as the way to insert filters on top at runtime? Though it seems it has always only worked for filters that use bs->backing, among which I think there aren't any user-creatable ones. So we're probably good. Kevin > blockdev.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/blockdev.c b/blockdev.c > index 29c6c6044a..c540802127 100644 > --- a/blockdev.c > +++ b/blockdev.c > @@ -1664,7 +1664,12 @@ static void external_snapshot_prepare(BlkActionState *common, > goto out; > } > > - if (state->new_bs->backing != NULL) { > + if (state->new_bs->drv->is_filter) { > + error_setg(errp, "Filters cannot be used as overlays"); > + goto out; > + } > + > + if (bdrv_filtered_cow_child(state->new_bs)) { > error_setg(errp, "The overlay already has a backing image"); > goto out; > } > -- > 2.21.0 >
On 10.09.19 17:02, Kevin Wolf wrote: > Am 09.08.2019 um 18:13 hat Max Reitz geschrieben: >> This allows us to differentiate between filters and nodes with COW >> backing files: Filters cannot be used as overlays at all (for this >> function). >> >> Signed-off-by: Max Reitz <mreitz@redhat.com> >> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> > > Didn't we occasionally advertise blockdev-snapshot as the way to insert > filters on top at runtime? I can only remember advertising for it as the only graph manipulation tool we had, and maybe saying “We’d want something like blockdev-snapshot for filters, too”. Max > Though it seems it has always only worked for > filters that use bs->backing, among which I think there aren't any > user-creatable ones. So we're probably good. > > Kevin > >> blockdev.c | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/blockdev.c b/blockdev.c >> index 29c6c6044a..c540802127 100644 >> --- a/blockdev.c >> +++ b/blockdev.c >> @@ -1664,7 +1664,12 @@ static void external_snapshot_prepare(BlkActionState *common, >> goto out; >> } >> >> - if (state->new_bs->backing != NULL) { >> + if (state->new_bs->drv->is_filter) { >> + error_setg(errp, "Filters cannot be used as overlays"); >> + goto out; >> + } >> + >> + if (bdrv_filtered_cow_child(state->new_bs)) { >> error_setg(errp, "The overlay already has a backing image"); >> goto out; >> } >> -- >> 2.21.0 >>
diff --git a/blockdev.c b/blockdev.c index 29c6c6044a..c540802127 100644 --- a/blockdev.c +++ b/blockdev.c @@ -1664,7 +1664,12 @@ static void external_snapshot_prepare(BlkActionState *common, goto out; } - if (state->new_bs->backing != NULL) { + if (state->new_bs->drv->is_filter) { + error_setg(errp, "Filters cannot be used as overlays"); + goto out; + } + + if (bdrv_filtered_cow_child(state->new_bs)) { error_setg(errp, "The overlay already has a backing image"); goto out; }