pve-qemu/debian/patches/pve/0047-block-io-accept-NULL-q...

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Stefan Reiter <s.reiter@proxmox.com>
Date: Tue, 2 Mar 2021 16:11:54 +0100
Subject: [PATCH] block/io: accept NULL qiov in bdrv_pad_request
Some operations, e.g. block-stream, perform reads while discarding the
results (only copy-on-read matters). In this case they will pass NULL as
the target QEMUIOVector, which will however trip bdrv_pad_request, since
it wants to extend its passed vector.
Simply check for NULL and do nothing, there's no reason to pad the
target if it will be discarded anyway.
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
block/io.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/block/io.c b/block/io.c
update submodule and patches to 7.1.0 Notable changes: * The only big change is the switch to using a custom QIOChannel for savevm-async, because the previously used QEMUFileOps was dropped. Changes to the current implementation: * Switch to vector based methods as required for an IO channel. For short reads the passed-in IO vector is stuffed with zeroes at the end, just to be sure. * For reading: The documentation in include/io/channel.h states that at least one byte should be read, so also error out when whe are at the very end instead of returning 0. * For reading: Fix off-by-one error when request goes beyond end. The wrong code piece was: if ((pos + size) > maxlen) { size = maxlen - pos - 1; } Previously, the last byte would not be read. It's actually possible to get a snapshot .raw file that has content all the way up the final 512 byte (= BDRV_SECTOR_SIZE) boundary without any trailing zero bytes (I wrote a script to do it). Luckily, it didn't cause a real issue, because qemu_loadvm_state() is not interested in the final (i.e. QEMU_VM_VMDESCRIPTION) section. The buffer for reading it is simply freed up afterwards and the function will assume that it read the whole section, even if that's not the case. * For writing: Make use of the generated blk_pwritev() wrapper instead of manually wrapping the coroutine to simplify and save a few lines. * Adapt to changed interfaces for blk_{pread,pwrite}: * a9262f551e ("block: Change blk_{pread,pwrite}() param order") * 3b35d4542c ("block: Add a 'flags' param to blk_pread()") * bf5b16fa40 ("block: Make blk_{pread,pwrite}() return 0 on success") Those changes especially affected the qemu-img dd patches, because the context also changed, but also some of our block drivers used the functions. * Drop qemu-common.h include: it got renamed after essentially everything was moved to other headers. The only remaining user I could find for things dropped from the header between 7.0 and 7.1 was qemu_get_vm_name() in the iscsi-initiatorname patch, but it already includes the header to which the function was moved. Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
2022-10-14 15:07:13 +03:00
index 0a8cbefe86..531b3b7a2d 100644
--- a/block/io.c
+++ b/block/io.c
update submodule and patches to 7.1.0 Notable changes: * The only big change is the switch to using a custom QIOChannel for savevm-async, because the previously used QEMUFileOps was dropped. Changes to the current implementation: * Switch to vector based methods as required for an IO channel. For short reads the passed-in IO vector is stuffed with zeroes at the end, just to be sure. * For reading: The documentation in include/io/channel.h states that at least one byte should be read, so also error out when whe are at the very end instead of returning 0. * For reading: Fix off-by-one error when request goes beyond end. The wrong code piece was: if ((pos + size) > maxlen) { size = maxlen - pos - 1; } Previously, the last byte would not be read. It's actually possible to get a snapshot .raw file that has content all the way up the final 512 byte (= BDRV_SECTOR_SIZE) boundary without any trailing zero bytes (I wrote a script to do it). Luckily, it didn't cause a real issue, because qemu_loadvm_state() is not interested in the final (i.e. QEMU_VM_VMDESCRIPTION) section. The buffer for reading it is simply freed up afterwards and the function will assume that it read the whole section, even if that's not the case. * For writing: Make use of the generated blk_pwritev() wrapper instead of manually wrapping the coroutine to simplify and save a few lines. * Adapt to changed interfaces for blk_{pread,pwrite}: * a9262f551e ("block: Change blk_{pread,pwrite}() param order") * 3b35d4542c ("block: Add a 'flags' param to blk_pread()") * bf5b16fa40 ("block: Make blk_{pread,pwrite}() return 0 on success") Those changes especially affected the qemu-img dd patches, because the context also changed, but also some of our block drivers used the functions. * Drop qemu-common.h include: it got renamed after essentially everything was moved to other headers. The only remaining user I could find for things dropped from the header between 7.0 and 7.1 was qemu_get_vm_name() in the iscsi-initiatorname patch, but it already includes the header to which the function was moved. Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
2022-10-14 15:07:13 +03:00
@@ -1734,6 +1734,10 @@ static int bdrv_pad_request(BlockDriverState *bs,
{
int ret;
+ if (!qiov) {
+ return 0;
+ }
+
bdrv_check_qiov_request(*offset, *bytes, *qiov, *qiov_offset, &error_abort);
if (!bdrv_init_padding(bs, *offset, *bytes, pad)) {