9750247ab0
-nbd: Fix regression with multiple meta contexts Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
61 lines
2.6 KiB
Diff
61 lines
2.6 KiB
Diff
From 32c6cb39cbadd6fc2026ff6311fcf58549f71d49 Mon Sep 17 00:00:00 2001
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From: Pan Nengyuan <pannengyuan@huawei.com>
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Date: Wed, 15 Apr 2020 14:29:04 +0800
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Subject: [PATCH] nbd: Fix regression with multiple meta contexts
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Detected by a hang in the libnbd testsuite. If a client requests
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multiple meta contexts (both base:allocation and qemu:dirty-bitmap:x)
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at the same time, our attempt to silence a false-positive warning
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about a potential uninitialized variable introduced botched logic: we
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were short-circuiting the second context, and never sending the
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NBD_REPLY_FLAG_DONE. Combining two 'if' into one 'if/else' in
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bdf200a55 was wrong (I'm a bit embarrassed that such a change was my
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initial suggestion after the v1 patch, then I did not review the v2
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patch that actually got committed). Revert that, and instead silence
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the false positive warning by replacing 'return ret' with 'return 0'
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(the value it always has at that point in the code, even though it
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eluded the deduction abilities of the robot that reported the false
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positive).
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Fixes: bdf200a5535
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Signed-off-by: Eric Blake <eblake@redhat.com>
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Message-Id: <20200206173832.130004-1-eblake@redhat.com>
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Reviewed-by: Laurent Vivier <laurent@vivier.eu>
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(cherry picked from commit 73e064ccf09d908febc83761addcc6e76feabf78)
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---
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nbd/server.c | 11 +++++++++--
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1 file changed, 9 insertions(+), 2 deletions(-)
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diff --git a/nbd/server.c b/nbd/server.c
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index aefb07d..3630352 100644
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--- a/nbd/server.c
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+++ b/nbd/server.c
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@@ -2304,15 +2304,22 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
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!client->export_meta.bitmap,
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NBD_META_ID_BASE_ALLOCATION,
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errp);
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- } else { /* client->export_meta.bitmap */
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+ if (ret < 0) {
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+ return ret;
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+ }
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+ }
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+ if (client->export_meta.bitmap) {
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ret = nbd_co_send_bitmap(client, request->handle,
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client->exp->export_bitmap,
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request->from, request->len,
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dont_fragment,
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true, NBD_META_ID_DIRTY_BITMAP, errp);
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+ if (ret < 0) {
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+ return ret;
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+ }
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}
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- return ret;
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+ return 0;
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} else {
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return nbd_send_generic_reply(client, request->handle, -EINVAL,
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"CMD_BLOCK_STATUS not negotiated",
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--
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1.8.3.1
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