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pve-qemu-qoup/debian/patches/pve/0051-qemu-img-dd-add-l-option-for-loading-a-snapshot.patch
Fiona Ebner 5b15e2ecaf 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 14:52:29 +02:00

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Fabian Ebner <f.ebner@proxmox.com>
Date: Mon, 7 Feb 2022 14:21:01 +0100
Subject: [PATCH] qemu-img: dd: add -l option for loading a snapshot
Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
docs/tools/qemu-img.rst | 6 +++---
qemu-img-cmds.hx | 4 ++--
qemu-img.c | 33 +++++++++++++++++++++++++++++++--
3 files changed, 36 insertions(+), 7 deletions(-)
diff --git a/docs/tools/qemu-img.rst b/docs/tools/qemu-img.rst
index 699229eef6..4189ced8bc 100644
--- a/docs/tools/qemu-img.rst
+++ b/docs/tools/qemu-img.rst
@@ -492,10 +492,10 @@ Command description:
it doesn't need to be specified separately in this case.
-.. option:: dd [--image-opts] [-U] [-f FMT] [-O OUTPUT_FMT] [-n] [bs=BLOCK_SIZE] [count=BLOCKS] [skip=BLOCKS] if=INPUT of=OUTPUT
+.. option:: dd [--image-opts] [-U] [-f FMT] [-O OUTPUT_FMT] [-n] [-l SNAPSHOT_PARAM] [bs=BLOCK_SIZE] [count=BLOCKS] [skip=BLOCKS] if=INPUT of=OUTPUT
- dd copies from *INPUT* file to *OUTPUT* file converting it from
- *FMT* format to *OUTPUT_FMT* format.
+ dd copies from *INPUT* file or snapshot *SNAPSHOT_PARAM* to *OUTPUT* file
+ converting it from *FMT* format to *OUTPUT_FMT* format.
The data is by default read and written using blocks of 512 bytes but can be
modified by specifying *BLOCK_SIZE*. If count=\ *BLOCKS* is specified
diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
index b5b0bb4467..36f97e1f19 100644
--- a/qemu-img-cmds.hx
+++ b/qemu-img-cmds.hx
@@ -58,9 +58,9 @@ SRST
ERST
DEF("dd", img_dd,
- "dd [--image-opts] [-U] [-f fmt] [-O output_fmt] [-n] [bs=block_size] [count=blocks] [skip=blocks] [osize=output_size] if=input of=output")
+ "dd [--image-opts] [-U] [-f fmt] [-O output_fmt] [-n] [-l snapshot_param] [bs=block_size] [count=blocks] [skip=blocks] [osize=output_size] if=input of=output")
SRST
-.. option:: dd [--image-opts] [-U] [-f FMT] [-O OUTPUT_FMT] [-n] [bs=BLOCK_SIZE] [count=BLOCKS] [skip=BLOCKS] [osize=OUTPUT_SIZE] if=INPUT of=OUTPUT
+.. option:: dd [--image-opts] [-U] [-f FMT] [-O OUTPUT_FMT] [-n] [-l SNAPSHOT_PARAM] [bs=BLOCK_SIZE] [count=BLOCKS] [skip=BLOCKS] [osize=OUTPUT_SIZE] if=INPUT of=OUTPUT
ERST
DEF("info", img_info,
diff --git a/qemu-img.c b/qemu-img.c
index c6b4a5567d..041c203fc3 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -4943,6 +4943,7 @@ static int img_dd(int argc, char **argv)
BlockDriver *drv = NULL, *proto_drv = NULL;
BlockBackend *blk1 = NULL, *blk2 = NULL;
QemuOpts *opts = NULL;
+ QemuOpts *sn_opts = NULL;
QemuOptsList *create_opts = NULL;
Error *local_err = NULL;
bool image_opts = false;
@@ -4952,6 +4953,7 @@ static int img_dd(int argc, char **argv)
int64_t size = 0, readsize = 0;
int64_t block_count = 0, out_pos, in_pos;
bool force_share = false, skip_create = false;
+ const char *snapshot_name = NULL;
struct DdInfo dd = {
.flags = 0,
.count = 0,
@@ -4989,7 +4991,7 @@ static int img_dd(int argc, char **argv)
{ 0, 0, 0, 0 }
};
- while ((c = getopt_long(argc, argv, ":hf:O:Un", long_options, NULL))) {
+ while ((c = getopt_long(argc, argv, ":hf:O:l:Un", long_options, NULL))) {
if (c == EOF) {
break;
}
@@ -5012,6 +5014,19 @@ static int img_dd(int argc, char **argv)
case 'n':
skip_create = true;
break;
+ case 'l':
+ if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) {
+ sn_opts = qemu_opts_parse_noisily(&internal_snapshot_opts,
+ optarg, false);
+ if (!sn_opts) {
+ error_report("Failed in parsing snapshot param '%s'",
+ optarg);
+ goto out;
+ }
+ } else {
+ snapshot_name = optarg;
+ }
+ break;
case 'U':
force_share = true;
break;
@@ -5071,11 +5086,24 @@ static int img_dd(int argc, char **argv)
if (dd.flags & C_IF) {
blk1 = img_open(image_opts, in.filename, fmt, 0, false, false,
force_share);
-
if (!blk1) {
ret = -1;
goto out;
}
+ if (sn_opts) {
+ bdrv_snapshot_load_tmp(blk_bs(blk1),
+ qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
+ qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME),
+ &local_err);
+ } else if (snapshot_name != NULL) {
+ bdrv_snapshot_load_tmp_by_id_or_name(blk_bs(blk1), snapshot_name,
+ &local_err);
+ }
+ if (local_err) {
+ error_reportf_err(local_err, "Failed to load snapshot: ");
+ ret = -1;
+ goto out;
+ }
}
if (dd.flags & C_OSIZE) {
@@ -5230,6 +5258,7 @@ static int img_dd(int argc, char **argv)
out:
g_free(arg);
qemu_opts_del(opts);
+ qemu_opts_del(sn_opts);
qemu_opts_free(create_opts);
blk_unref(blk1);
blk_unref(blk2);
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