061e9ceb36
All callers of the function pass an address, so dereferencing once
before checking for NULL is required. It's also necessary to update
bytes and offset nevertheless, so the request will actually be aligned
later and not trigger an assertion failure.
Seems like this was accidentally broken in 8dca018 ("udpate and rebase
to QEMU v6.0.0") and this is effectively a revert to the original
version of the patch. The qiov functions changed back then, which
might've been the reason Stefan tried to simplify the patch.
Should fix live-import for certain kinds of VMDK images.
Reported-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
65 lines
2.3 KiB
Diff
65 lines
2.3 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Stefan Reiter <s.reiter@proxmox.com>
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Date: Tue, 2 Mar 2021 16:11:54 +0100
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Subject: [PATCH] block/io: accept NULL qiov in bdrv_pad_request
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Some operations, e.g. block-stream, perform reads while discarding the
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results (only copy-on-read matters). In this case they will pass NULL as
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the target QEMUIOVector, which will however trip bdrv_pad_request, since
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it wants to extend its passed vector.
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If there is no qiov, no operation can be done with it, but the bytes
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and offset still need to be updated, so the subsequent aligned read
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will actually be aligned and not run into an assertion failure.
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Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
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[FE: do update bytes and offset in any case]
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Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
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---
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block/io.c | 29 ++++++++++++++++-------------
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1 file changed, 16 insertions(+), 13 deletions(-)
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diff --git a/block/io.c b/block/io.c
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index 83d1b1dfdc..e927881e40 100644
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--- a/block/io.c
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+++ b/block/io.c
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@@ -1723,22 +1723,25 @@ static int bdrv_pad_request(BlockDriverState *bs,
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return 0;
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}
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- sliced_iov = qemu_iovec_slice(*qiov, *qiov_offset, *bytes,
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- &sliced_head, &sliced_tail,
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- &sliced_niov);
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-
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- /* Guaranteed by bdrv_check_request32() */
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- assert(*bytes <= SIZE_MAX);
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- ret = bdrv_create_padded_qiov(bs, pad, sliced_iov, sliced_niov,
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- sliced_head, *bytes);
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- if (ret < 0) {
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- bdrv_padding_finalize(pad);
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- return ret;
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+ if (qiov && *qiov) {
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+ sliced_iov = qemu_iovec_slice(*qiov, *qiov_offset, *bytes,
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+ &sliced_head, &sliced_tail,
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+ &sliced_niov);
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+
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+ /* Guaranteed by bdrv_check_request32() */
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+ assert(*bytes <= SIZE_MAX);
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+ ret = bdrv_create_padded_qiov(bs, pad, sliced_iov, sliced_niov,
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+ sliced_head, *bytes);
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+ if (ret < 0) {
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+ bdrv_padding_finalize(pad);
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+ return ret;
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+ }
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+ *qiov = &pad->local_qiov;
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+ *qiov_offset = 0;
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}
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+
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*bytes += pad->head + pad->tail;
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*offset -= pad->head;
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- *qiov = &pad->local_qiov;
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- *qiov_offset = 0;
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if (padded) {
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*padded = true;
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}
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