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>
82 lines
3.0 KiB
Diff
82 lines
3.0 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: John Snow <jsnow@redhat.com>
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Date: Mon, 6 Apr 2020 12:17:04 +0200
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Subject: [PATCH] drive-mirror: add support for conditional and always bitmap
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sync modes
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Teach mirror two new tricks for using bitmaps:
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Always: no matter what, we synchronize the copy_bitmap back to the
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sync_bitmap. In effect, this allows us resume a failed mirror at a later
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date.
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Conditional: On success only, we sync the bitmap. This is akin to
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incremental backup modes; we can use this bitmap to later refresh a
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successfully created mirror.
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
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---
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block/mirror.c | 24 ++++++++++++++++++------
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1 file changed, 18 insertions(+), 6 deletions(-)
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diff --git a/block/mirror.c b/block/mirror.c
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index f2eca983f1..b6475d50ad 100644
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--- a/block/mirror.c
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+++ b/block/mirror.c
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@@ -673,8 +673,6 @@ static int mirror_exit_common(Job *job)
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bdrv_unfreeze_backing_chain(mirror_top_bs, target_bs);
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}
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- bdrv_release_dirty_bitmap(s->dirty_bitmap);
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-
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/* Make sure that the source BDS doesn't go away during bdrv_replace_node,
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* before we can call bdrv_drained_end */
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bdrv_ref(src);
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@@ -775,6 +773,18 @@ static int mirror_exit_common(Job *job)
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block_job_remove_all_bdrv(bjob);
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bdrv_replace_node(mirror_top_bs, mirror_top_bs->backing->bs, &error_abort);
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+ if (s->sync_bitmap) {
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+ if (s->bitmap_mode == BITMAP_SYNC_MODE_ALWAYS ||
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+ (s->bitmap_mode == BITMAP_SYNC_MODE_ON_SUCCESS &&
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+ job->ret == 0 && ret == 0)) {
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+ /* Success; synchronize copy back to sync. */
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+ bdrv_clear_dirty_bitmap(s->sync_bitmap, NULL);
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+ bdrv_merge_dirty_bitmap(s->sync_bitmap, s->dirty_bitmap,
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+ NULL, &error_abort);
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+ }
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+ }
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+ bdrv_release_dirty_bitmap(s->dirty_bitmap);
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+
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bs_opaque->job = NULL;
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bdrv_drained_end(src);
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@@ -1634,10 +1644,6 @@ static BlockJob *mirror_start_job(
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" sync mode",
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MirrorSyncMode_str(sync_mode));
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return NULL;
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- } else if (bitmap_mode != BITMAP_SYNC_MODE_NEVER) {
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- error_setg(errp,
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- "Bitmap Sync Mode '%s' is not supported by Mirror",
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- BitmapSyncMode_str(bitmap_mode));
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}
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} else if (bitmap) {
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error_setg(errp,
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@@ -1654,6 +1660,12 @@ static BlockJob *mirror_start_job(
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return NULL;
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}
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granularity = bdrv_dirty_bitmap_granularity(bitmap);
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+
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+ if (bitmap_mode != BITMAP_SYNC_MODE_NEVER) {
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+ if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_DEFAULT, errp)) {
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+ return NULL;
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+ }
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+ }
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} else if (granularity == 0) {
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granularity = bdrv_get_default_bitmap_granularity(target);
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}
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