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envelope-from=andrey.shinkevich@virtuozzo.com; helo=EUR02-AM5-obe.outbound.protection.outlook.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/14 10:28:19 X-ACL-Warn: Detected OS = Windows NT kernel [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MSGID_FROM_MTA_HEADER=0.001, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 14.10.2020 13:44, Max Reitz wrote: > On 12.10.20 19:43, Andrey Shinkevich wrote: >> Provide API for the COR-filter insertion/removal. >> Also, drop the filter child permissions for an inactive state when the >> filter node is being removed. >> >> Signed-off-by: Andrey Shinkevich >> Reviewed-by: Vladimir Sementsov-Ogievskiy >> --- >> block/copy-on-read.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++++++++ >> block/copy-on-read.h | 35 +++++++++++++++++++++ >> 2 files changed, 123 insertions(+) >> create mode 100644 block/copy-on-read.h >> >> diff --git a/block/copy-on-read.c b/block/copy-on-read.c >> index cb03e0f..bcccf0f 100644 >> --- a/block/copy-on-read.c >> +++ b/block/copy-on-read.c > > [...] > >> @@ -159,4 +188,63 @@ static void bdrv_copy_on_read_init(void) >> bdrv_register(&bdrv_copy_on_read); >> } >> >> + >> +BlockDriverState *bdrv_cor_filter_append(BlockDriverState *bs, >> + QDict *node_options, >> + int flags, Error **errp) > > I had hoped you could make this a generic block layer function. :( > > (Because it really is rather generic) > > *shrug* Actually, I did (and still can do) that for the 'append node' function only but not for the 'drop node' one so far... diff --git a/block.c b/block.c index 11ab55f..f41e876 100644 --- a/block.c +++ b/block.c @@ -4669,6 +4669,55 @@ static void bdrv_delete(BlockDriverState *bs) g_free(bs); } +BlockDriverState *bdrv_insert_node(BlockDriverState *bs, QDict *node_options, + int flags, Error **errp) +{ + BlockDriverState *new_node_bs; + Error *local_err = NULL; + + new_node_bs = bdrv_open(NULL, NULL, node_options, flags, errp); + if (new_node_bs == NULL) { + error_prepend(errp, "Could not create node: "); + return NULL; + } + + bdrv_drained_begin(bs); + bdrv_replace_node(bs, new_node_bs, &local_err); + bdrv_drained_end(bs); + + if (local_err) { + bdrv_unref(new_node_bs); + error_propagate(errp, local_err); + return NULL; + } + + return new_node_bs; +} + +void bdrv_remove_node(BlockDriverState *bs) +{ + BdrvChild *child; + BlockDriverState *inferior_bs; + + child = bdrv_filter_or_cow_child(bs); + if (!child) { + return; + } + inferior_bs = child->bs; + + /* Retain the BDS until we complete the graph change. */ + bdrv_ref(inferior_bs); + /* Hold a guest back from writing while permissions are being reset. */ + bdrv_drained_begin(inferior_bs); + /* Refresh permissions before the graph change. */ + bdrv_child_refresh_perms(bs, child, &error_abort); + bdrv_replace_node(bs, inferior_bs, &error_abort); + + bdrv_drained_end(inferior_bs); + bdrv_unref(inferior_bs); + bdrv_unref(bs); +} So, it is an intermediate solution in this patch of the series. I am going to make both functions generic once Vladimir overhauls the QEMU permission update system. Otherwise, the COR-filter node cannot be removed from the backing chain gracefully. Thank you for your r-b. If the next version comes, I can move the 'append node' function only to the generic layer. Andrey > > Reviewed-by: Max Reitz > >> +{ >> + BlockDriverState *cor_filter_bs; >> + Error *local_err = NULL; >> + >> + cor_filter_bs = bdrv_open(NULL, NULL, node_options, flags, errp); >> + if (cor_filter_bs == NULL) { >> + error_prepend(errp, "Could not create COR-filter node: "); >> + return NULL; >> + } >> + >> + if (!qdict_get_try_str(node_options, "node-name")) { >> + cor_filter_bs->implicit = true; >> + } >> + >> + bdrv_drained_begin(bs); >> + bdrv_replace_node(bs, cor_filter_bs, &local_err); >> + bdrv_drained_end(bs); >> + >> + if (local_err) { >> + bdrv_unref(cor_filter_bs); >> + error_propagate(errp, local_err); >> + return NULL; >> + } >> + >> + return cor_filter_bs; >> +} >