73 lines
2.7 KiB
Diff
73 lines
2.7 KiB
Diff
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From: Hanna Reitz <hreitz@redhat.com>
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Date: Thu, 25 Nov 2021 14:53:16 +0100
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Subject: block-backend: Retain permissions after migration
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Git-commit: 492a119610129f65217580790971fa038e5492d3
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After migration, the permissions the guest device wants to impose on its
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BlockBackend are stored in blk->perm and blk->shared_perm. In
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blk_root_activate(), we take our permissions, but keep all shared
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permissions open by calling `blk_set_perm(blk->perm, BLK_PERM_ALL)`.
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Only afterwards (immediately or later, depending on the runstate) do we
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restrict the shared permissions by calling
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`blk_set_perm(blk->perm, blk->shared_perm)`. Unfortunately, our first
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call with shared_perm=BLK_PERM_ALL has overwritten blk->shared_perm to
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be BLK_PERM_ALL, so this is a no-op and the set of shared permissions is
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not restricted.
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Fix this bug by saving the set of shared permissions before invoking
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blk_set_perm() with BLK_PERM_ALL and restoring it afterwards.
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Fixes: 5f7772c4d0cf32f4e779fcd5a69ae4dae24aeebf
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("block-backend: Defer shared_perm tightening migration
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completion")
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Reported-by: Peng Liang <liangpeng10@huawei.com>
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Signed-off-by: Hanna Reitz <hreitz@redhat.com>
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Message-Id: <20211125135317.186576-2-hreitz@redhat.com>
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Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
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Tested-by: Peng Liang <liangpeng10@huawei.com>
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Signed-off-by: Li Zhang <lizhang@suse.de>
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---
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block/block-backend.c | 11 +++++++++++
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1 file changed, 11 insertions(+)
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diff --git a/block/block-backend.c b/block/block-backend.c
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index 12ef80ea170c04a15500b42bc5e7..41e388fe1f30af8f3cf6a872b37a 100644
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--- a/block/block-backend.c
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+++ b/block/block-backend.c
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@@ -190,6 +190,7 @@ static void blk_root_activate(BdrvChild *child, Error **errp)
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{
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BlockBackend *blk = child->opaque;
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Error *local_err = NULL;
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+ uint64_t saved_shared_perm;
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if (!blk->disable_perm) {
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return;
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@@ -197,12 +198,22 @@ static void blk_root_activate(BdrvChild *child, Error **errp)
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blk->disable_perm = false;
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+ /*
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+ * blk->shared_perm contains the permissions we want to share once
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+ * migration is really completely done. For now, we need to share
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+ * all; but we also need to retain blk->shared_perm, which is
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+ * overwritten by a successful blk_set_perm() call. Save it and
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+ * restore it below.
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+ */
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+ saved_shared_perm = blk->shared_perm;
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+
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blk_set_perm(blk, blk->perm, BLK_PERM_ALL, &local_err);
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if (local_err) {
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error_propagate(errp, local_err);
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blk->disable_perm = true;
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return;
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}
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+ blk->shared_perm = saved_shared_perm;
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if (runstate_check(RUN_STATE_INMIGRATE)) {
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/* Activation can happen when migration process is still active, for
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