From 331170e0732617b931959f7c617af3823f8fe95e Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Thu, 24 Sep 2020 17:27:09 +0200 Subject: [PATCH] block/export: Create BlockBackend in blk_exp_add() Every export type will need a BlockBackend, so creating it centrally in blk_exp_add() instead of the .create driver callback avoids duplication. Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz Message-Id: <20200924152717.287415-24-kwolf@redhat.com> Acked-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf --- block/export/export.c | 49 +++++++++++++++++++++++++++++++++++++++---- blockdev-nbd.c | 33 ++++------------------------- include/block/nbd.h | 4 ++-- nbd/server.c | 38 +++++++++++---------------------- 4 files changed, 63 insertions(+), 61 deletions(-) diff --git a/block/export/export.c b/block/export/export.c index ad374a6649..8702c233f3 100644 --- a/block/export/export.c +++ b/block/export/export.c @@ -58,7 +58,10 @@ static const BlockExportDriver *blk_exp_find_driver(BlockExportType type) BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp) { const BlockExportDriver *drv; - BlockExport *exp; + BlockExport *exp = NULL; + BlockDriverState *bs; + BlockBackend *blk; + AioContext *ctx; int ret; if (!id_wellformed(export->id)) { @@ -76,6 +79,33 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp) return NULL; } + bs = bdrv_lookup_bs(NULL, export->node_name, errp); + if (!bs) { + return NULL; + } + + ctx = bdrv_get_aio_context(bs); + aio_context_acquire(ctx); + + /* + * Block exports are used for non-shared storage migration. Make sure + * that BDRV_O_INACTIVE is cleared and the image is ready for write + * access since the export could be available before migration handover. + * ctx was acquired in the caller. + */ + bdrv_invalidate_cache(bs, NULL); + + blk = blk_new(ctx, BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL); + ret = blk_insert_bs(blk, bs, errp); + if (ret < 0) { + goto fail; + } + + if (!export->has_writethrough) { + export->writethrough = false; + } + blk_set_enable_write_cache(blk, !export->writethrough); + assert(drv->instance_size >= sizeof(BlockExport)); exp = g_malloc0(drv->instance_size); *exp = (BlockExport) { @@ -83,19 +113,30 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp) .refcount = 1, .user_owned = true, .id = g_strdup(export->id), + .ctx = ctx, + .blk = blk, }; ret = drv->create(exp, export, errp); if (ret < 0) { - g_free(exp->id); - g_free(exp); - return NULL; + goto fail; } assert(exp->blk != NULL); QLIST_INSERT_HEAD(&block_exports, exp, next); + + aio_context_release(ctx); return exp; + +fail: + blk_unref(blk); + aio_context_release(ctx); + if (exp) { + g_free(exp->id); + g_free(exp); + } + return NULL; } /* Callers must hold exp->ctx lock */ diff --git a/blockdev-nbd.c b/blockdev-nbd.c index 4a9a1be571..cdbbcdb958 100644 --- a/blockdev-nbd.c +++ b/blockdev-nbd.c @@ -177,9 +177,6 @@ int nbd_export_create(BlockExport *exp, BlockExportOptions *exp_args, Error **errp) { BlockExportOptionsNbd *arg = &exp_args->u.nbd; - BlockDriverState *bs = NULL; - AioContext *aio_context; - int ret; assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD); @@ -207,38 +204,16 @@ int nbd_export_create(BlockExport *exp, BlockExportOptions *exp_args, return -EEXIST; } - bs = bdrv_lookup_bs(NULL, exp_args->node_name, errp); - if (!bs) { - return -ENOENT; - } - - aio_context = bdrv_get_aio_context(bs); - aio_context_acquire(aio_context); - if (!arg->has_writable) { arg->writable = false; } - if (bdrv_is_read_only(bs) && arg->writable) { - ret = -EINVAL; + if (blk_is_read_only(exp->blk) && arg->writable) { error_setg(errp, "Cannot export read-only node as writable"); - goto out; + return -EINVAL; } - if (!exp_args->has_writethrough) { - exp_args->writethrough = false; - } - - ret = nbd_export_new(exp, bs, arg->name, arg->description, arg->bitmap, - !arg->writable, !arg->writable, - exp_args->writethrough, errp); - if (ret < 0) { - goto out; - } - - ret = 0; - out: - aio_context_release(aio_context); - return ret; + return nbd_export_new(exp, arg->name, arg->description, arg->bitmap, + !arg->writable, !arg->writable, errp); } void qmp_nbd_server_add(NbdServerAddOptions *arg, Error **errp) diff --git a/include/block/nbd.h b/include/block/nbd.h index a4dc1f9e54..5270b7eadd 100644 --- a/include/block/nbd.h +++ b/include/block/nbd.h @@ -332,10 +332,10 @@ typedef struct NBDClient NBDClient; int nbd_export_create(BlockExport *exp, BlockExportOptions *exp_args, Error **errp); -int nbd_export_new(BlockExport *blk_exp, BlockDriverState *bs, +int nbd_export_new(BlockExport *blk_exp, const char *name, const char *desc, const char *bitmap, bool readonly, bool shared, - bool writethrough, Error **errp); + Error **errp); void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk); AioContext *nbd_export_aio_context(NBDExport *exp); diff --git a/nbd/server.c b/nbd/server.c index f9af45c480..6c8532de23 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -1507,56 +1507,42 @@ void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk) blk_add_remove_bs_notifier(blk, &nbd_exp->eject_notifier); } -int nbd_export_new(BlockExport *blk_exp, BlockDriverState *bs, +int nbd_export_new(BlockExport *blk_exp, const char *name, const char *desc, const char *bitmap, bool readonly, bool shared, - bool writethrough, Error **errp) + Error **errp) { NBDExport *exp = container_of(blk_exp, NBDExport, common); - AioContext *ctx; - BlockBackend *blk; + BlockBackend *blk = blk_exp->blk; int64_t size; - uint64_t perm; + uint64_t perm, shared_perm; int ret; - size = bdrv_getlength(bs); + size = blk_getlength(blk); if (size < 0) { error_setg_errno(errp, -size, "Failed to determine the NBD export's length"); return size; } - ctx = bdrv_get_aio_context(bs); - blk_exp->ctx = ctx; - - /* - * NBD exports are used for non-shared storage migration. Make sure - * that BDRV_O_INACTIVE is cleared and the image is ready for write - * access since the export could be available before migration handover. - * ctx was acquired in the caller. - */ assert(name && strlen(name) <= NBD_MAX_STRING_SIZE); - bdrv_invalidate_cache(bs, NULL); - /* Don't allow resize while the NBD server is running, otherwise we don't * care what happens with the node. */ - perm = BLK_PERM_CONSISTENT_READ; + blk_get_perm(blk, &perm, &shared_perm); + if (!readonly) { perm |= BLK_PERM_WRITE; } - blk = blk_new(ctx, perm, - BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | - BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD); - ret = blk_insert_bs(blk, bs, errp); + + ret = blk_set_perm(blk, perm, shared_perm & ~BLK_PERM_RESIZE, errp); if (ret < 0) { - goto fail; + return ret; } - blk_set_enable_write_cache(blk, !writethrough); + blk_set_allow_aio_context_change(blk, true); QTAILQ_INIT(&exp->clients); - exp->common.blk = blk; exp->name = g_strdup(name); assert(!desc || strlen(desc) <= NBD_MAX_STRING_SIZE); exp->description = g_strdup(desc); @@ -1574,6 +1560,7 @@ int nbd_export_new(BlockExport *blk_exp, BlockDriverState *bs, exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE); if (bitmap) { + BlockDriverState *bs = blk_bs(blk); BdrvDirtyBitmap *bm = NULL; while (bs) { @@ -1620,7 +1607,6 @@ int nbd_export_new(BlockExport *blk_exp, BlockDriverState *bs, return 0; fail: - blk_unref(blk); g_free(exp->name); g_free(exp->description); return ret;