diff --git a/blockdev-nbd.c b/blockdev-nbd.c index 104789e521..a9f79c6778 100644 --- a/blockdev-nbd.c +++ b/blockdev-nbd.c @@ -189,6 +189,30 @@ void qmp_nbd_server_add(const char *device, bool has_name, const char *name, nbd_export_put(exp); } +void qmp_nbd_server_remove(const char *name, + bool has_mode, NbdServerRemoveMode mode, + Error **errp) +{ + NBDExport *exp; + + if (!nbd_server) { + error_setg(errp, "NBD server not running"); + return; + } + + exp = nbd_export_find(name); + if (exp == NULL) { + error_setg(errp, "Export '%s' is not found", name); + return; + } + + if (!has_mode) { + mode = NBD_SERVER_REMOVE_MODE_SAFE; + } + + nbd_export_remove(exp, mode, errp); +} + void qmp_nbd_server_stop(Error **errp) { nbd_export_close_all(); diff --git a/include/block/nbd.h b/include/block/nbd.h index 978e443366..ee74ec391a 100644 --- a/include/block/nbd.h +++ b/include/block/nbd.h @@ -261,6 +261,7 @@ NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size, bool writethrough, BlockBackend *on_eject_blk, Error **errp); void nbd_export_close(NBDExport *exp); +void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp); void nbd_export_get(NBDExport *exp); void nbd_export_put(NBDExport *exp); diff --git a/nbd/server.c b/nbd/server.c index 6caa8d17be..112e3f69df 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -1177,6 +1177,19 @@ void nbd_export_close(NBDExport *exp) nbd_export_put(exp); } +void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp) +{ + if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) { + nbd_export_close(exp); + return; + } + + assert(mode == NBD_SERVER_REMOVE_MODE_SAFE); + + error_setg(errp, "export '%s' still in use", exp->name); + error_append_hint(errp, "Use mode='hard' to force client disconnect\n"); +} + void nbd_export_get(NBDExport *exp) { assert(exp->refcount > 0); diff --git a/qapi/block.json b/qapi/block.json index 353e3a45bd..c694524002 100644 --- a/qapi/block.json +++ b/qapi/block.json @@ -227,6 +227,47 @@ { 'command': 'nbd-server-add', 'data': {'device': 'str', '*name': 'str', '*writable': 'bool'} } +## +# @NbdServerRemoveMode: +# +# Mode for removing an NBD export. +# +# @safe: Remove export if there are no existing connections, fail otherwise. +# +# @hard: Drop all connections immediately and remove export. +# +# Potential additional modes to be added in the future: +# +# hide: Just hide export from new clients, leave existing connections as is. +# Remove export after all clients are disconnected. +# +# soft: Hide export from new clients, answer with ESHUTDOWN for all further +# requests from existing clients. +# +# Since: 2.12 +## +{'enum': 'NbdServerRemoveMode', 'data': ['safe', 'hard']} + +## +# @nbd-server-remove: +# +# Remove NBD export by name. +# +# @name: Export name. +# +# @mode: Mode of command operation. See @NbdServerRemoveMode description. +# Default is 'safe'. +# +# Returns: error if +# - the server is not running +# - export is not found +# - mode is 'safe' and there are existing connections +# +# Since: 2.12 +## +{ 'command': 'nbd-server-remove', + 'data': {'name': 'str', '*mode': 'NbdServerRemoveMode'} } + ## # @nbd-server-stop: #