The only caller pass copy_range and compress both false. Let's just drop these arguments. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210824083856.17408-35-vsementsov@virtuozzo.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Signed-off-by: Hanna Reitz <hreitz@redhat.com>
257 lines
7.5 KiB
C
257 lines
7.5 KiB
C
/*
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* copy-before-write filter driver
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*
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* The driver performs Copy-Before-Write (CBW) operation: it is injected above
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* some node, and before each write it copies _old_ data to the target node.
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*
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* Copyright (c) 2018-2021 Virtuozzo International GmbH.
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*
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* Author:
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* Sementsov-Ogievskiy Vladimir <vsementsov@virtuozzo.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "qemu/osdep.h"
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#include "sysemu/block-backend.h"
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#include "qemu/cutils.h"
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#include "qapi/error.h"
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#include "block/block_int.h"
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#include "block/qdict.h"
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#include "block/block-copy.h"
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#include "block/copy-before-write.h"
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typedef struct BDRVCopyBeforeWriteState {
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BlockCopyState *bcs;
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BdrvChild *target;
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} BDRVCopyBeforeWriteState;
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static coroutine_fn int cbw_co_preadv(
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BlockDriverState *bs, uint64_t offset, uint64_t bytes,
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QEMUIOVector *qiov, int flags)
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{
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return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
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}
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static coroutine_fn int cbw_do_copy_before_write(BlockDriverState *bs,
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uint64_t offset, uint64_t bytes, BdrvRequestFlags flags)
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{
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BDRVCopyBeforeWriteState *s = bs->opaque;
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uint64_t off, end;
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int64_t cluster_size = block_copy_cluster_size(s->bcs);
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if (flags & BDRV_REQ_WRITE_UNCHANGED) {
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return 0;
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}
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off = QEMU_ALIGN_DOWN(offset, cluster_size);
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end = QEMU_ALIGN_UP(offset + bytes, cluster_size);
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return block_copy(s->bcs, off, end - off, true);
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}
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static int coroutine_fn cbw_co_pdiscard(BlockDriverState *bs,
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int64_t offset, int bytes)
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{
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int ret = cbw_do_copy_before_write(bs, offset, bytes, 0);
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if (ret < 0) {
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return ret;
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}
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return bdrv_co_pdiscard(bs->file, offset, bytes);
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}
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static int coroutine_fn cbw_co_pwrite_zeroes(BlockDriverState *bs,
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int64_t offset, int bytes, BdrvRequestFlags flags)
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{
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int ret = cbw_do_copy_before_write(bs, offset, bytes, flags);
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if (ret < 0) {
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return ret;
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}
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return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags);
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}
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static coroutine_fn int cbw_co_pwritev(BlockDriverState *bs,
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uint64_t offset,
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uint64_t bytes,
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QEMUIOVector *qiov, int flags)
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{
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int ret = cbw_do_copy_before_write(bs, offset, bytes, flags);
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if (ret < 0) {
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return ret;
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}
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return bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags);
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}
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static int coroutine_fn cbw_co_flush(BlockDriverState *bs)
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{
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if (!bs->file) {
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return 0;
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}
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return bdrv_co_flush(bs->file->bs);
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}
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static void cbw_refresh_filename(BlockDriverState *bs)
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{
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pstrcpy(bs->exact_filename, sizeof(bs->exact_filename),
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bs->file->bs->filename);
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}
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static void cbw_child_perm(BlockDriverState *bs, BdrvChild *c,
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BdrvChildRole role,
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BlockReopenQueue *reopen_queue,
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uint64_t perm, uint64_t shared,
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uint64_t *nperm, uint64_t *nshared)
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{
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if (!(role & BDRV_CHILD_FILTERED)) {
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/*
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* Target child
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*
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* Share write to target (child_file), to not interfere
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* with guest writes to its disk which may be in target backing chain.
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* Can't resize during a backup block job because we check the size
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* only upfront.
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*/
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*nshared = BLK_PERM_ALL & ~BLK_PERM_RESIZE;
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*nperm = BLK_PERM_WRITE;
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} else {
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/* Source child */
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bdrv_default_perms(bs, c, role, reopen_queue,
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perm, shared, nperm, nshared);
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if (!QLIST_EMPTY(&bs->parents)) {
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if (perm & BLK_PERM_WRITE) {
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*nperm = *nperm | BLK_PERM_CONSISTENT_READ;
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}
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*nshared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
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}
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}
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}
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static int cbw_open(BlockDriverState *bs, QDict *options, int flags,
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Error **errp)
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{
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BDRVCopyBeforeWriteState *s = bs->opaque;
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BdrvDirtyBitmap *copy_bitmap;
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bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
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BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
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false, errp);
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if (!bs->file) {
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return -EINVAL;
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}
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s->target = bdrv_open_child(NULL, options, "target", bs, &child_of_bds,
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BDRV_CHILD_DATA, false, errp);
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if (!s->target) {
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return -EINVAL;
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}
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bs->total_sectors = bs->file->bs->total_sectors;
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bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED |
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(BDRV_REQ_FUA & bs->file->bs->supported_write_flags);
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bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED |
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((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
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bs->file->bs->supported_zero_flags);
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s->bcs = block_copy_state_new(bs->file, s->target, errp);
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if (!s->bcs) {
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error_prepend(errp, "Cannot create block-copy-state: ");
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return -EINVAL;
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}
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copy_bitmap = block_copy_dirty_bitmap(s->bcs);
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bdrv_set_dirty_bitmap(copy_bitmap, 0, bdrv_dirty_bitmap_size(copy_bitmap));
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return 0;
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}
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static void cbw_close(BlockDriverState *bs)
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{
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BDRVCopyBeforeWriteState *s = bs->opaque;
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block_copy_state_free(s->bcs);
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s->bcs = NULL;
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}
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BlockDriver bdrv_cbw_filter = {
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.format_name = "copy-before-write",
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.instance_size = sizeof(BDRVCopyBeforeWriteState),
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.bdrv_open = cbw_open,
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.bdrv_close = cbw_close,
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.bdrv_co_preadv = cbw_co_preadv,
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.bdrv_co_pwritev = cbw_co_pwritev,
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.bdrv_co_pwrite_zeroes = cbw_co_pwrite_zeroes,
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.bdrv_co_pdiscard = cbw_co_pdiscard,
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.bdrv_co_flush = cbw_co_flush,
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.bdrv_refresh_filename = cbw_refresh_filename,
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.bdrv_child_perm = cbw_child_perm,
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.is_filter = true,
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};
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BlockDriverState *bdrv_cbw_append(BlockDriverState *source,
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BlockDriverState *target,
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const char *filter_node_name,
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BlockCopyState **bcs,
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Error **errp)
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{
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ERRP_GUARD();
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BDRVCopyBeforeWriteState *state;
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BlockDriverState *top;
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QDict *opts;
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assert(source->total_sectors == target->total_sectors);
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opts = qdict_new();
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qdict_put_str(opts, "driver", "copy-before-write");
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if (filter_node_name) {
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qdict_put_str(opts, "node-name", filter_node_name);
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}
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qdict_put_str(opts, "file", bdrv_get_node_name(source));
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qdict_put_str(opts, "target", bdrv_get_node_name(target));
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top = bdrv_insert_node(source, opts, BDRV_O_RDWR, errp);
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if (!top) {
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return NULL;
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}
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state = top->opaque;
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*bcs = state->bcs;
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return top;
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}
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void bdrv_cbw_drop(BlockDriverState *bs)
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{
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bdrv_drop_filter(bs, &error_abort);
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bdrv_unref(bs);
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}
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static void cbw_init(void)
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{
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bdrv_register(&bdrv_cbw_filter);
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}
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block_init(cbw_init);
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