pve-qemu/debian/patches/pve/0059-vma-create-support-64K...

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Fabian Ebner <f.ebner@proxmox.com>
Date: Wed, 22 Jun 2022 10:45:11 +0200
Subject: [PATCH] vma: create: support 64KiB-unaligned input images
which fixes backing up templates with such disks in PVE, for example
efitype=4m EFI disks on a file-based storage (size = 540672).
If there is not enough left to read, blk_co_preadv will return -EIO,
so limit the size in the last iteration.
For writing, an unaligned end is already handled correctly.
The call to memset is not strictly necessary, because writing also
checks that it doesn't write data beyond the end of the image. But
there are two reasons to do it:
1. It's cleaner that way.
2. It allows detecting when the final piece is all zeroes, which might
not happen if the buffer still contains data from the previous
iteration.
Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>
---
vma.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/vma.c b/vma.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 e6e9ffc7fe..304f02bc84 100644
--- a/vma.c
+++ b/vma.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
@@ -548,7 +548,7 @@ static void coroutine_fn backup_run(void *opaque)
struct iovec iov;
QEMUIOVector qiov;
- int64_t start, end;
+ int64_t start, end, readlen;
int ret = 0;
unsigned char *buf = blk_blockalign(job->target, VMA_CLUSTER_SIZE);
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
@@ -562,8 +562,16 @@ static void coroutine_fn backup_run(void *opaque)
iov.iov_len = VMA_CLUSTER_SIZE;
qemu_iovec_init_external(&qiov, &iov, 1);
+ if (start + 1 == end) {
+ memset(buf, 0, VMA_CLUSTER_SIZE);
+ readlen = job->len - start * VMA_CLUSTER_SIZE;
+ assert(readlen > 0 && readlen <= VMA_CLUSTER_SIZE);
+ } else {
+ readlen = VMA_CLUSTER_SIZE;
+ }
+
ret = blk_co_preadv(job->target, start * VMA_CLUSTER_SIZE,
- VMA_CLUSTER_SIZE, &qiov, 0);
+ readlen, &qiov, 0);
if (ret < 0) {
vma_writer_set_error(job->vmaw, "read error", -1);
goto out;