From 30dbc81d310cc5c78589ab689083371c4bfced1f Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Thu, 24 Sep 2020 17:27:11 +0200 Subject: [PATCH] block/export: Move writable to BlockExportOptions The 'writable' option is a basic option that will probably be applicable to most if not all export types that we will implement. Move it from NBD to the generic BlockExport layer. Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz Message-Id: <20200924152717.287415-26-kwolf@redhat.com> Acked-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf --- block/export/export.c | 16 +++++++++++++++- blockdev-nbd.c | 18 +++++------------- nbd/server.c | 5 ----- qapi/block-export.json | 15 ++++++++++----- qemu-nbd.c | 4 ++-- 5 files changed, 32 insertions(+), 26 deletions(-) diff --git a/block/export/export.c b/block/export/export.c index 657bb58b51..f2c00d13bf 100644 --- a/block/export/export.c +++ b/block/export/export.c @@ -62,6 +62,7 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp) BlockDriverState *bs; BlockBackend *blk; AioContext *ctx; + uint64_t perm; int ret; if (!id_wellformed(export->id)) { @@ -84,6 +85,14 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp) return NULL; } + if (!export->has_writable) { + export->writable = false; + } + if (bdrv_is_read_only(bs) && export->writable) { + error_setg(errp, "Cannot export read-only node as writable"); + return NULL; + } + ctx = bdrv_get_aio_context(bs); aio_context_acquire(ctx); @@ -95,7 +104,12 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp) */ bdrv_invalidate_cache(bs, NULL); - blk = blk_new(ctx, BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL); + perm = BLK_PERM_CONSISTENT_READ; + if (export->writable) { + perm |= BLK_PERM_WRITE; + } + + blk = blk_new(ctx, perm, BLK_PERM_ALL); ret = blk_insert_bs(blk, bs, errp); if (ret < 0) { goto fail; diff --git a/blockdev-nbd.c b/blockdev-nbd.c index cdbbcdb958..30e165c23f 100644 --- a/blockdev-nbd.c +++ b/blockdev-nbd.c @@ -204,16 +204,8 @@ int nbd_export_create(BlockExport *exp, BlockExportOptions *exp_args, return -EEXIST; } - if (!arg->has_writable) { - arg->writable = false; - } - if (blk_is_read_only(exp->blk) && arg->writable) { - error_setg(errp, "Cannot export read-only node as writable"); - return -EINVAL; - } - return nbd_export_new(exp, arg->name, arg->description, arg->bitmap, - !arg->writable, !arg->writable, errp); + !exp_args->writable, !exp_args->writable, errp); } void qmp_nbd_server_add(NbdServerAddOptions *arg, Error **errp) @@ -241,13 +233,13 @@ void qmp_nbd_server_add(NbdServerAddOptions *arg, Error **errp) .type = BLOCK_EXPORT_TYPE_NBD, .id = g_strdup(arg->name), .node_name = g_strdup(bdrv_get_node_name(bs)), + .has_writable = arg->has_writable, + .writable = arg->writable, .u.nbd = { .has_name = true, .name = g_strdup(arg->name), .has_description = arg->has_description, .description = g_strdup(arg->description), - .has_writable = arg->has_writable, - .writable = arg->writable, .has_bitmap = arg->has_bitmap, .bitmap = g_strdup(arg->bitmap), }, @@ -259,8 +251,8 @@ void qmp_nbd_server_add(NbdServerAddOptions *arg, Error **errp) * block-export-add. */ if (bdrv_is_read_only(bs)) { - export_opts->u.nbd.has_writable = true; - export_opts->u.nbd.writable = false; + export_opts->has_writable = true; + export_opts->writable = false; } export = blk_exp_add(export_opts, errp); diff --git a/nbd/server.c b/nbd/server.c index 6c8532de23..465ec9e762 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -1530,11 +1530,6 @@ int nbd_export_new(BlockExport *blk_exp, /* Don't allow resize while the NBD server is running, otherwise we don't * care what happens with the node. */ blk_get_perm(blk, &perm, &shared_perm); - - if (!readonly) { - perm |= BLK_PERM_WRITE; - } - ret = blk_set_perm(blk, perm, shared_perm & ~BLK_PERM_RESIZE, errp); if (ret < 0) { return ret; diff --git a/qapi/block-export.json b/qapi/block-export.json index 91b042b453..3ce4d6276b 100644 --- a/qapi/block-export.json +++ b/qapi/block-export.json @@ -74,9 +74,6 @@ # @description: Free-form description of the export, up to 4096 bytes. # (Since 5.0) # -# @writable: Whether clients should be able to write to the device via the -# NBD connection (default false). -# # @bitmap: Also export the dirty bitmap reachable from @device, so the # NBD client can use NBD_OPT_SET_META_CONTEXT with # "qemu:dirty-bitmap:NAME" to inspect the bitmap. (since 4.0) @@ -85,7 +82,7 @@ ## { 'struct': 'BlockExportOptionsNbd', 'data': { '*name': 'str', '*description': 'str', - '*writable': 'bool', '*bitmap': 'str' } } + '*bitmap': 'str' } } ## # @NbdServerAddOptions: @@ -94,11 +91,15 @@ # # @device: The device name or node name of the node to be exported # +# @writable: Whether clients should be able to write to the device via the +# NBD connection (default false). +# # Since: 5.0 ## { 'struct': 'NbdServerAddOptions', 'base': 'BlockExportOptionsNbd', - 'data': { 'device': 'str' } } + 'data': { 'device': 'str', + '*writable': 'bool' } } ## # @nbd-server-add: @@ -188,6 +189,9 @@ # # @node-name: The node name of the block node to be exported (since: 5.2) # +# @writable: True if clients should be able to write to the export +# (default false) +# # @writethrough: If true, caches are flushed after every write request to the # export before completion is signalled. (since: 5.2; # default: false) @@ -198,6 +202,7 @@ 'base': { 'type': 'BlockExportType', 'id': 'str', 'node-name': 'str', + '*writable': 'bool', '*writethrough': 'bool' }, 'discriminator': 'type', 'data': { diff --git a/qemu-nbd.c b/qemu-nbd.c index 66cb8f91b1..bacb69b089 100644 --- a/qemu-nbd.c +++ b/qemu-nbd.c @@ -1068,13 +1068,13 @@ int main(int argc, char **argv) .node_name = g_strdup(bdrv_get_node_name(bs)), .has_writethrough = true, .writethrough = writethrough, + .has_writable = true, + .writable = !readonly, .u.nbd = { .has_name = true, .name = g_strdup(export_name), .has_description = !!export_description, .description = g_strdup(export_description), - .has_writable = true, - .writable = !readonly, .has_bitmap = !!bitmap, .bitmap = g_strdup(bitmap), },