5b15e2ecaf
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>
33 lines
1.2 KiB
Diff
33 lines
1.2 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Wolfgang Bumiller <w.bumiller@proxmox.com>
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Date: Mon, 6 Apr 2020 12:16:36 +0200
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Subject: [PATCH] PVE: [Config] rbd: block: rbd: disable
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rbd_cache_writethrough_until_flush
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Either the cache mode asks for a cache or not. There's no
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point in having a "temporary" cache mode. This option AFAIK
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was introduced as a hack for ancient virtio drivers. If
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anything, we should have a separate option for it. Better
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yet, VMs affected by the related issue should simply
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explicitly choose writethrough.
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Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
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Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
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---
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block/rbd.c | 2 ++
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1 file changed, 2 insertions(+)
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diff --git a/block/rbd.c b/block/rbd.c
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index f826410f40..64a8d7d48b 100644
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--- a/block/rbd.c
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+++ b/block/rbd.c
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@@ -820,6 +820,8 @@ static int qemu_rbd_connect(rados_t *cluster, rados_ioctx_t *io_ctx,
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rados_conf_set(*cluster, "rbd_cache", "false");
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}
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+ rados_conf_set(*cluster, "rbd_cache_writethrough_until_flush", "false");
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+
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r = rados_connect(*cluster);
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if (r < 0) {
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error_setg_errno(errp, -r, "error connecting");
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