From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54027) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gNgQm-0001hh-Ax for qemu-devel@nongnu.org; Fri, 16 Nov 2018 10:53:17 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gNgQl-0000J7-6x for qemu-devel@nongnu.org; Fri, 16 Nov 2018 10:53:16 -0500 From: Max Reitz Date: Fri, 16 Nov 2018 16:53:00 +0100 Message-Id: <20181116155302.22472-2-mreitz@redhat.com> In-Reply-To: <20181116155302.22472-1-mreitz@redhat.com> References: <20181116155302.22472-1-mreitz@redhat.com> Subject: [Qemu-devel] [PATCH for-3.1? 1/3] block: Always abort reopen after prepare succeeded List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, Max Reitz , Alberto Garcia , Kevin Wolf , Fam Zheng bdrv_reopen_multiple() does not invoke bdrv_reopen_abort() for the element of the reopen queue for which bdrv_reopen_prepare() failed, because it assumes that the prepare function will have rolled back all changes already. However, bdrv_reopen_prepare() does not do this in every case: It may notice an error after BlockDriver.bdrv_reopen_prepare() succeeded, and it will not invoke BlockDriver.bdrv_reopen_abort() then; and neither will bdrv_reopen_multiple(), as explained above. This is wrong because we must always call .bdrv_reopen_commit() or .bdrv_reopen_abort() after .bdrv_reopen_prepare() has succeeded. Otherwise, the block driver has no chance to undo what it has done in its implementation of .bdrv_reopen_prepare(). To fix this, bdrv_reopen_prepare() has to call .bdrv_reopen_abort() if it wants to return an error after .bdrv_reopen_prepare() has succeeded. Signed-off-by: Max Reitz --- block.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/block.c b/block.c index fd67e14dfa..7f5859aa74 100644 --- a/block.c +++ b/block.c @@ -3332,7 +3332,7 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, if (!qobject_is_equal(new, old)) { error_setg(errp, "Cannot change the option '%s'", entry->key); ret = -EINVAL; - goto error; + goto late_error; } } while ((entry = qdict_next(reopen_state->options, entry))); } @@ -3340,7 +3340,7 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, ret = bdrv_check_perm(reopen_state->bs, queue, reopen_state->perm, reopen_state->shared_perm, NULL, errp); if (ret < 0) { - goto error; + goto late_error; } ret = 0; @@ -3354,6 +3354,19 @@ error: qobject_unref(orig_reopen_opts); g_free(discard); return ret; + +late_error: + /* drv->bdrv_reopen_prepare() has succeeded, so we need to call + * drv->bdrv_reopen_abort() before signaling an error + * (bdrv_reopen_multiple() will not call bdrv_reopen_abort() when + * the respective bdrv_reopen_prepare() failed) */ + if (drv->bdrv_reopen_abort) { + drv->bdrv_reopen_abort(reopen_state); + } + qemu_opts_del(opts); + qobject_unref(orig_reopen_opts); + g_free(discard); + return ret; } /* -- 2.17.2