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>
103 lines
3.1 KiB
Diff
103 lines
3.1 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 12:16:41 +0200
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Subject: [PATCH] PVE: [Up] qemu-img dd: add isize parameter
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for writing small images from stdin to bigger ones
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In order to distinguish between an actually unexpected and
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an expected end of input.
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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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Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
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---
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qemu-img.c | 28 +++++++++++++++++++++++++---
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1 file changed, 25 insertions(+), 3 deletions(-)
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diff --git a/qemu-img.c b/qemu-img.c
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index 74afcb79ef..14594d44b6 100644
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--- a/qemu-img.c
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+++ b/qemu-img.c
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@@ -4827,11 +4827,13 @@ static int img_bitmap(int argc, char **argv)
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#define C_OF 010
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#define C_SKIP 020
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#define C_OSIZE 040
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+#define C_ISIZE 0100
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struct DdInfo {
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unsigned int flags;
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int64_t count;
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int64_t osize;
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+ int64_t isize;
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};
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struct DdIo {
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@@ -4920,6 +4922,19 @@ static int img_dd_osize(const char *arg,
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return 0;
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}
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+static int img_dd_isize(const char *arg,
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+ struct DdIo *in, struct DdIo *out,
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+ struct DdInfo *dd)
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+{
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+ dd->isize = cvtnum("size", arg);
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+
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+ if (dd->isize < 0) {
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+ return 1;
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+ }
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+
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+ return 0;
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+}
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+
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static int img_dd(int argc, char **argv)
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{
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int ret = 0;
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@@ -4934,12 +4949,14 @@ static int img_dd(int argc, char **argv)
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int c, i;
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const char *out_fmt = "raw";
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const char *fmt = NULL;
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- int64_t size = 0;
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+ int64_t size = 0, readsize = 0;
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int64_t block_count = 0, out_pos, in_pos;
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bool force_share = false;
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struct DdInfo dd = {
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.flags = 0,
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.count = 0,
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+ .osize = 0,
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+ .isize = -1,
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};
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struct DdIo in = {
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.bsz = 512, /* Block size is by default 512 bytes */
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@@ -4961,6 +4978,7 @@ static int img_dd(int argc, char **argv)
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{ "of", img_dd_of, C_OF },
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{ "skip", img_dd_skip, C_SKIP },
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{ "osize", img_dd_osize, C_OSIZE },
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+ { "isize", img_dd_isize, C_ISIZE },
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{ NULL, NULL, 0 }
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};
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const struct option long_options[] = {
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@@ -5157,9 +5175,10 @@ static int img_dd(int argc, char **argv)
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in.buf = g_new(uint8_t, in.bsz);
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- for (out_pos = 0; in_pos < size; block_count++) {
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+ readsize = (dd.isize > 0) ? dd.isize : size;
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+ for (out_pos = 0; in_pos < readsize; block_count++) {
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int in_ret, out_ret;
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- int bytes = (in_pos + in.bsz > size) ? size - in_pos : in.bsz;
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+ int bytes = (in_pos + in.bsz > readsize) ? readsize - in_pos : in.bsz;
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if (blk1) {
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in_ret = blk_pread(blk1, in_pos, bytes, in.buf, 0);
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if (in_ret == 0) {
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@@ -5168,6 +5187,9 @@ static int img_dd(int argc, char **argv)
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} else {
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in_ret = read(STDIN_FILENO, in.buf, bytes);
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if (in_ret == 0) {
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+ if (dd.isize == 0) {
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+ goto out;
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+ }
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/* early EOF is considered an error */
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error_report("Input ended unexpectedly");
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ret = -1;
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