2021-03-15 18:41:24 +03:00
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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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Simply check for NULL and do nothing, there's no reason to pad the
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target if it will be discarded anyway.
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2022-01-13 12:34:33 +03:00
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Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
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2021-03-15 18:41:24 +03:00
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---
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2021-05-27 13:43:32 +03:00
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block/io.c | 4 ++++
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1 file changed, 4 insertions(+)
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2021-03-15 18:41:24 +03:00
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diff --git a/block/io.c b/block/io.c
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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
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index 0a8cbefe86..531b3b7a2d 100644
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2021-03-15 18:41:24 +03:00
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--- a/block/io.c
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+++ b/block/io.c
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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
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@@ -1734,6 +1734,10 @@ static int bdrv_pad_request(BlockDriverState *bs,
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2021-05-27 13:43:32 +03:00
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{
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int ret;
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2021-03-15 18:41:24 +03:00
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2021-05-27 13:43:32 +03:00
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+ if (!qiov) {
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+ return 0;
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2021-03-15 18:41:24 +03:00
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+ }
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+
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2021-05-27 13:43:32 +03:00
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bdrv_check_qiov_request(*offset, *bytes, *qiov, *qiov_offset, &error_abort);
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2021-03-15 18:41:24 +03:00
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2021-05-27 13:43:32 +03:00
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if (!bdrv_init_padding(bs, *offset, *bytes, pad)) {
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