From patchwork Fri Aug 9 16:13:52 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 1144817 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 464r985qnwz9sNF for ; Sat, 10 Aug 2019 02:21:48 +1000 (AEST) Received: from localhost ([::1]:60932 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hw7eE-00005n-Sq for incoming@patchwork.ozlabs.org; Fri, 09 Aug 2019 12:21:46 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:57483) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hw7Y1-0003LR-1O for qemu-devel@nongnu.org; Fri, 09 Aug 2019 12:15:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hw7Xz-0004VW-EX for qemu-devel@nongnu.org; Fri, 09 Aug 2019 12:15:20 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59190) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hw7Xv-0004TP-RY; Fri, 09 Aug 2019 12:15:16 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1F08030A00AB; Fri, 9 Aug 2019 16:15:15 +0000 (UTC) Received: from localhost (unknown [10.40.205.179]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3D296600CC; Fri, 9 Aug 2019 16:15:13 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Fri, 9 Aug 2019 18:13:52 +0200 Message-Id: <20190809161407.11920-28-mreitz@redhat.com> In-Reply-To: <20190809161407.11920-1-mreitz@redhat.com> References: <20190809161407.11920-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Fri, 09 Aug 2019 16:15:15 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v6 27/42] commit: Deal with filters 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: , Cc: Kevin Wolf , Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" This includes some permission limiting (for example, we only need to take the RESIZE permission if the base is smaller than the top). Signed-off-by: Max Reitz Reviewed-by: Vladimir Sementsov-Ogievskiy --- block/block-backend.c | 16 +++++--- block/commit.c | 96 +++++++++++++++++++++++++++++++------------ blockdev.c | 6 ++- 3 files changed, 85 insertions(+), 33 deletions(-) diff --git a/block/block-backend.c b/block/block-backend.c index c13c5c83b0..0bc592d023 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -2180,11 +2180,17 @@ int blk_commit_all(void) AioContext *aio_context = blk_get_aio_context(blk); aio_context_acquire(aio_context); - if (blk_is_inserted(blk) && blk->root->bs->backing) { - int ret = bdrv_commit(blk->root->bs); - if (ret < 0) { - aio_context_release(aio_context); - return ret; + if (blk_is_inserted(blk)) { + BlockDriverState *non_filter; + + /* Legacy function, so skip implicit filters */ + non_filter = bdrv_skip_implicit_filters(blk->root->bs); + if (bdrv_filtered_cow_child(non_filter)) { + int ret = bdrv_commit(non_filter); + if (ret < 0) { + aio_context_release(aio_context); + return ret; + } } } aio_context_release(aio_context); diff --git a/block/commit.c b/block/commit.c index 5a7672c7c7..40d1c8eeac 100644 --- a/block/commit.c +++ b/block/commit.c @@ -37,6 +37,7 @@ typedef struct CommitBlockJob { BlockBackend *top; BlockBackend *base; BlockDriverState *base_bs; + BlockDriverState *above_base; BlockdevOnError on_error; bool base_read_only; bool chain_frozen; @@ -110,7 +111,7 @@ static void commit_abort(Job *job) * XXX Can (or should) we somehow keep 'consistent read' blocked even * after the failed/cancelled commit job is gone? If we already wrote * something to base, the intermediate images aren't valid any more. */ - bdrv_replace_node(s->commit_top_bs, backing_bs(s->commit_top_bs), + bdrv_replace_node(s->commit_top_bs, s->commit_top_bs->backing->bs, &error_abort); bdrv_unref(s->commit_top_bs); @@ -174,7 +175,7 @@ static int coroutine_fn commit_run(Job *job, Error **errp) break; } /* Copy if allocated above the base */ - ret = bdrv_is_allocated_above(blk_bs(s->top), blk_bs(s->base), false, + ret = bdrv_is_allocated_above(blk_bs(s->top), s->above_base, true, offset, COMMIT_BUFFER_SIZE, &n); copy = (ret == 1); trace_commit_one_iteration(s, offset, n, ret); @@ -267,15 +268,35 @@ void commit_start(const char *job_id, BlockDriverState *bs, CommitBlockJob *s; BlockDriverState *iter; BlockDriverState *commit_top_bs = NULL; + BlockDriverState *filtered_base; Error *local_err = NULL; + int64_t base_size, top_size; + uint64_t perms, iter_shared_perms; int ret; assert(top != bs); - if (top == base) { + if (bdrv_skip_rw_filters(top) == bdrv_skip_rw_filters(base)) { error_setg(errp, "Invalid files for merge: top and base are the same"); return; } + base_size = bdrv_getlength(base); + if (base_size < 0) { + error_setg_errno(errp, -base_size, "Could not inquire base image size"); + return; + } + + top_size = bdrv_getlength(top); + if (top_size < 0) { + error_setg_errno(errp, -top_size, "Could not inquire top image size"); + return; + } + + perms = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE; + if (base_size < top_size) { + perms |= BLK_PERM_RESIZE; + } + s = block_job_create(job_id, &commit_job_driver, NULL, bs, 0, BLK_PERM_ALL, speed, creation_flags, NULL, NULL, errp); if (!s) { @@ -315,17 +336,43 @@ void commit_start(const char *job_id, BlockDriverState *bs, s->commit_top_bs = commit_top_bs; - /* Block all nodes between top and base, because they will - * disappear from the chain after this operation. */ - assert(bdrv_chain_contains(top, base)); - for (iter = top; iter != base; iter = backing_bs(iter)) { - /* XXX BLK_PERM_WRITE needs to be allowed so we don't block ourselves - * at s->base (if writes are blocked for a node, they are also blocked - * for its backing file). The other options would be a second filter - * driver above s->base. */ + /* + * Block all nodes between top and base, because they will + * disappear from the chain after this operation. + * Note that this assumes that the user is fine with removing all + * nodes (including R/W filters) between top and base. Assuring + * this is the responsibility of the interface (i.e. whoever calls + * commit_start()). + */ + s->above_base = bdrv_find_overlay(top, base); + assert(s->above_base); + + /* + * The topmost node with + * bdrv_skip_rw_filters(filtered_base) == bdrv_skip_rw_filters(base) + */ + filtered_base = bdrv_filtered_cow_bs(s->above_base); + assert(bdrv_skip_rw_filters(filtered_base) == bdrv_skip_rw_filters(base)); + + /* + * XXX BLK_PERM_WRITE needs to be allowed so we don't block ourselves + * at s->base (if writes are blocked for a node, they are also blocked + * for its backing file). The other options would be a second filter + * driver above s->base. + */ + iter_shared_perms = BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE; + + for (iter = top; iter != base; iter = bdrv_filtered_bs(iter)) { + if (iter == filtered_base) { + /* + * From here on, all nodes are filters on the base. This + * allows us to share BLK_PERM_CONSISTENT_READ. + */ + iter_shared_perms |= BLK_PERM_CONSISTENT_READ; + } + ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0, - BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE, - errp); + iter_shared_perms, errp); if (ret < 0) { goto fail; } @@ -342,9 +389,7 @@ void commit_start(const char *job_id, BlockDriverState *bs, } s->base = blk_new(s->common.job.aio_context, - BLK_PERM_CONSISTENT_READ - | BLK_PERM_WRITE - | BLK_PERM_RESIZE, + perms, BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD | BLK_PERM_WRITE_UNCHANGED); @@ -412,19 +457,22 @@ int bdrv_commit(BlockDriverState *bs) if (!drv) return -ENOMEDIUM; - if (!bs->backing) { + backing_file_bs = bdrv_filtered_cow_bs(bs); + + if (!backing_file_bs) { return -ENOTSUP; } if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, NULL) || - bdrv_op_is_blocked(bs->backing->bs, BLOCK_OP_TYPE_COMMIT_TARGET, NULL)) { + bdrv_op_is_blocked(backing_file_bs, BLOCK_OP_TYPE_COMMIT_TARGET, NULL)) + { return -EBUSY; } - ro = bs->backing->bs->read_only; + ro = backing_file_bs->read_only; if (ro) { - if (bdrv_reopen_set_read_only(bs->backing->bs, false, NULL)) { + if (bdrv_reopen_set_read_only(backing_file_bs, false, NULL)) { return -EACCES; } } @@ -440,8 +488,6 @@ int bdrv_commit(BlockDriverState *bs) } /* Insert commit_top block node above backing, so we can write to it */ - backing_file_bs = backing_bs(bs); - commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, NULL, BDRV_O_RDWR, &local_err); if (commit_top_bs == NULL) { @@ -526,15 +572,13 @@ ro_cleanup: qemu_vfree(buf); blk_unref(backing); - if (backing_file_bs) { - bdrv_set_backing_hd(bs, backing_file_bs, &error_abort); - } + bdrv_set_backing_hd(bs, backing_file_bs, &error_abort); bdrv_unref(commit_top_bs); blk_unref(src); if (ro) { /* ignoring error return here */ - bdrv_reopen_set_read_only(bs->backing->bs, true, NULL); + bdrv_reopen_set_read_only(backing_file_bs, true, NULL); } return ret; diff --git a/blockdev.c b/blockdev.c index c6f79b4e0e..7bef41c0b0 100644 --- a/blockdev.c +++ b/blockdev.c @@ -1094,7 +1094,7 @@ void hmp_commit(Monitor *mon, const QDict *qdict) return; } - bs = blk_bs(blk); + bs = bdrv_skip_implicit_filters(blk_bs(blk)); aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); @@ -3454,7 +3454,9 @@ void qmp_block_commit(bool has_job_id, const char *job_id, const char *device, assert(bdrv_get_aio_context(base_bs) == aio_context); - for (iter = top_bs; iter != backing_bs(base_bs); iter = backing_bs(iter)) { + for (iter = top_bs; iter != bdrv_filtered_bs(base_bs); + iter = bdrv_filtered_bs(iter)) + { if (bdrv_op_is_blocked(iter, BLOCK_OP_TYPE_COMMIT_TARGET, errp)) { goto out; }