From 168f27ca545f530ac694ed596bdafc8fa3c26860 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Fri, 15 Mar 2019 18:10:00 +0100 Subject: [PATCH 004/163] block: Always abort reopen after prepare succeeded RH-Author: Kevin Wolf Message-id: <20190315181010.14964-5-kwolf@redhat.com> Patchwork-id: 84881 O-Subject: [RHEL-7.7 qemu-kvm-rhev PATCH 04/14] block: Always abort reopen after prepare succeeded Bugzilla: 1685989 RH-Acked-by: John Snow RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Miroslav Rezanina From: Max Reitz 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 Reviewed-by: Alberto Garcia Signed-off-by: Kevin Wolf (cherry picked from commit 9ad08c44566bf4466c6263c71d43e9f7a354d4ba) Signed-off-by: Kevin Wolf Signed-off-by: Miroslav Rezanina --- block.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/block.c b/block.c index c3148cc..2f1b4d1 100644 --- a/block.c +++ b/block.c @@ -3191,6 +3191,7 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, QemuOpts *opts; const char *value; bool read_only; + bool drv_prepared = false; assert(reopen_state != NULL); assert(reopen_state->bs->drv != NULL); @@ -3260,6 +3261,8 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, goto error; } + drv_prepared = true; + /* Options that are not handled are only okay if they are unchanged * compared to the old state. It is expected that some options are only * used for the initial open, but not reopen (e.g. filename) */ @@ -3303,6 +3306,15 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, ret = 0; error: + if (ret < 0 && drv_prepared) { + /* 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() has failed) */ + if (drv->bdrv_reopen_abort) { + drv->bdrv_reopen_abort(reopen_state); + } + } qemu_opts_del(opts); return ret; } -- 1.8.3.1