1d003e0aeSVladimir Sementsov-Ogievskiy /*
2d003e0aeSVladimir Sementsov-Ogievskiy * copy-before-write filter driver
3d003e0aeSVladimir Sementsov-Ogievskiy *
4d003e0aeSVladimir Sementsov-Ogievskiy * The driver performs Copy-Before-Write (CBW) operation: it is injected above
5d003e0aeSVladimir Sementsov-Ogievskiy * some node, and before each write it copies _old_ data to the target node.
6d003e0aeSVladimir Sementsov-Ogievskiy *
7d003e0aeSVladimir Sementsov-Ogievskiy * Copyright (c) 2018-2021 Virtuozzo International GmbH.
8d003e0aeSVladimir Sementsov-Ogievskiy *
9d003e0aeSVladimir Sementsov-Ogievskiy * Author:
10d003e0aeSVladimir Sementsov-Ogievskiy * Sementsov-Ogievskiy Vladimir <vsementsov@virtuozzo.com>
11d003e0aeSVladimir Sementsov-Ogievskiy *
12d003e0aeSVladimir Sementsov-Ogievskiy * This program is free software; you can redistribute it and/or modify
13d003e0aeSVladimir Sementsov-Ogievskiy * it under the terms of the GNU General Public License as published by
14d003e0aeSVladimir Sementsov-Ogievskiy * the Free Software Foundation; either version 2 of the License, or
15d003e0aeSVladimir Sementsov-Ogievskiy * (at your option) any later version.
16d003e0aeSVladimir Sementsov-Ogievskiy *
17d003e0aeSVladimir Sementsov-Ogievskiy * This program is distributed in the hope that it will be useful,
18d003e0aeSVladimir Sementsov-Ogievskiy * but WITHOUT ANY WARRANTY; without even the implied warranty of
19d003e0aeSVladimir Sementsov-Ogievskiy * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20d003e0aeSVladimir Sementsov-Ogievskiy * GNU General Public License for more details.
21d003e0aeSVladimir Sementsov-Ogievskiy *
22d003e0aeSVladimir Sementsov-Ogievskiy * You should have received a copy of the GNU General Public License
23d003e0aeSVladimir Sementsov-Ogievskiy * along with this program. If not, see <http://www.gnu.org/licenses/>.
24d003e0aeSVladimir Sementsov-Ogievskiy */
25d003e0aeSVladimir Sementsov-Ogievskiy
26d003e0aeSVladimir Sementsov-Ogievskiy #include "qemu/osdep.h"
2779ef0cebSVladimir Sementsov-Ogievskiy #include "qapi/qmp/qjson.h"
28d003e0aeSVladimir Sementsov-Ogievskiy
29d003e0aeSVladimir Sementsov-Ogievskiy #include "sysemu/block-backend.h"
30d003e0aeSVladimir Sementsov-Ogievskiy #include "qemu/cutils.h"
31d003e0aeSVladimir Sementsov-Ogievskiy #include "qapi/error.h"
32d003e0aeSVladimir Sementsov-Ogievskiy #include "block/block_int.h"
33d003e0aeSVladimir Sementsov-Ogievskiy #include "block/qdict.h"
34d003e0aeSVladimir Sementsov-Ogievskiy #include "block/block-copy.h"
35e2c1c34fSMarkus Armbruster #include "block/dirty-bitmap.h"
36d003e0aeSVladimir Sementsov-Ogievskiy
37d003e0aeSVladimir Sementsov-Ogievskiy #include "block/copy-before-write.h"
38af5bcd77SVladimir Sementsov-Ogievskiy #include "block/reqlist.h"
39d003e0aeSVladimir Sementsov-Ogievskiy
405f3a3cd7SVladimir Sementsov-Ogievskiy #include "qapi/qapi-visit-block-core.h"
415f3a3cd7SVladimir Sementsov-Ogievskiy
42d003e0aeSVladimir Sementsov-Ogievskiy typedef struct BDRVCopyBeforeWriteState {
43d003e0aeSVladimir Sementsov-Ogievskiy BlockCopyState *bcs;
44d003e0aeSVladimir Sementsov-Ogievskiy BdrvChild *target;
45f1bb39a8SVladimir Sementsov-Ogievskiy OnCbwError on_cbw_error;
466db7fd1cSVladimir Sementsov-Ogievskiy uint32_t cbw_timeout_ns;
47af5bcd77SVladimir Sementsov-Ogievskiy
48af5bcd77SVladimir Sementsov-Ogievskiy /*
49af5bcd77SVladimir Sementsov-Ogievskiy * @lock: protects access to @access_bitmap, @done_bitmap and
50af5bcd77SVladimir Sementsov-Ogievskiy * @frozen_read_reqs
51af5bcd77SVladimir Sementsov-Ogievskiy */
52af5bcd77SVladimir Sementsov-Ogievskiy CoMutex lock;
53af5bcd77SVladimir Sementsov-Ogievskiy
54af5bcd77SVladimir Sementsov-Ogievskiy /*
55af5bcd77SVladimir Sementsov-Ogievskiy * @access_bitmap: represents areas allowed for reading by fleecing user.
56af5bcd77SVladimir Sementsov-Ogievskiy * Reading from non-dirty areas leads to -EACCES.
57af5bcd77SVladimir Sementsov-Ogievskiy */
58af5bcd77SVladimir Sementsov-Ogievskiy BdrvDirtyBitmap *access_bitmap;
59af5bcd77SVladimir Sementsov-Ogievskiy
60af5bcd77SVladimir Sementsov-Ogievskiy /*
61af5bcd77SVladimir Sementsov-Ogievskiy * @done_bitmap: represents areas that was successfully copied to @target by
62af5bcd77SVladimir Sementsov-Ogievskiy * copy-before-write operations.
63af5bcd77SVladimir Sementsov-Ogievskiy */
64af5bcd77SVladimir Sementsov-Ogievskiy BdrvDirtyBitmap *done_bitmap;
65af5bcd77SVladimir Sementsov-Ogievskiy
66af5bcd77SVladimir Sementsov-Ogievskiy /*
67af5bcd77SVladimir Sementsov-Ogievskiy * @frozen_read_reqs: current read requests for fleecing user in bs->file
68af5bcd77SVladimir Sementsov-Ogievskiy * node. These areas must not be rewritten by guest.
69af5bcd77SVladimir Sementsov-Ogievskiy */
70af5bcd77SVladimir Sementsov-Ogievskiy BlockReqList frozen_read_reqs;
71f1bb39a8SVladimir Sementsov-Ogievskiy
72f1bb39a8SVladimir Sementsov-Ogievskiy /*
73f1bb39a8SVladimir Sementsov-Ogievskiy * @snapshot_error is normally zero. But on first copy-before-write failure
74f1bb39a8SVladimir Sementsov-Ogievskiy * when @on_cbw_error == ON_CBW_ERROR_BREAK_SNAPSHOT, @snapshot_error takes
75f1bb39a8SVladimir Sementsov-Ogievskiy * value of this error (<0). After that all in-flight and further
76f1bb39a8SVladimir Sementsov-Ogievskiy * snapshot-API requests will fail with that error.
77f1bb39a8SVladimir Sementsov-Ogievskiy */
78f1bb39a8SVladimir Sementsov-Ogievskiy int snapshot_error;
79d003e0aeSVladimir Sementsov-Ogievskiy } BDRVCopyBeforeWriteState;
80d003e0aeSVladimir Sementsov-Ogievskiy
81b9b10c35SKevin Wolf static int coroutine_fn GRAPH_RDLOCK
cbw_co_preadv(BlockDriverState * bs,int64_t offset,int64_t bytes,QEMUIOVector * qiov,BdrvRequestFlags flags)82b9b10c35SKevin Wolf cbw_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
83f7ef38ddSVladimir Sementsov-Ogievskiy QEMUIOVector *qiov, BdrvRequestFlags flags)
84d003e0aeSVladimir Sementsov-Ogievskiy {
853c1e6327SVladimir Sementsov-Ogievskiy return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
86d003e0aeSVladimir Sementsov-Ogievskiy }
87d003e0aeSVladimir Sementsov-Ogievskiy
block_copy_cb(void * opaque)886db7fd1cSVladimir Sementsov-Ogievskiy static void block_copy_cb(void *opaque)
896db7fd1cSVladimir Sementsov-Ogievskiy {
906db7fd1cSVladimir Sementsov-Ogievskiy BlockDriverState *bs = opaque;
916db7fd1cSVladimir Sementsov-Ogievskiy
926db7fd1cSVladimir Sementsov-Ogievskiy bdrv_dec_in_flight(bs);
936db7fd1cSVladimir Sementsov-Ogievskiy }
946db7fd1cSVladimir Sementsov-Ogievskiy
95af5bcd77SVladimir Sementsov-Ogievskiy /*
96af5bcd77SVladimir Sementsov-Ogievskiy * Do copy-before-write operation.
97af5bcd77SVladimir Sementsov-Ogievskiy *
98af5bcd77SVladimir Sementsov-Ogievskiy * On failure guest request must be failed too.
99af5bcd77SVladimir Sementsov-Ogievskiy *
100af5bcd77SVladimir Sementsov-Ogievskiy * On success, we also wait for all in-flight fleecing read requests in source
101af5bcd77SVladimir Sementsov-Ogievskiy * node, and it's guaranteed that after cbw_do_copy_before_write() successful
102af5bcd77SVladimir Sementsov-Ogievskiy * return there are no such requests and they will never appear.
103af5bcd77SVladimir Sementsov-Ogievskiy */
cbw_do_copy_before_write(BlockDriverState * bs,uint64_t offset,uint64_t bytes,BdrvRequestFlags flags)104d003e0aeSVladimir Sementsov-Ogievskiy static coroutine_fn int cbw_do_copy_before_write(BlockDriverState *bs,
105d003e0aeSVladimir Sementsov-Ogievskiy uint64_t offset, uint64_t bytes, BdrvRequestFlags flags)
106d003e0aeSVladimir Sementsov-Ogievskiy {
107d003e0aeSVladimir Sementsov-Ogievskiy BDRVCopyBeforeWriteState *s = bs->opaque;
108af5bcd77SVladimir Sementsov-Ogievskiy int ret;
109d003e0aeSVladimir Sementsov-Ogievskiy uint64_t off, end;
110b518e9e9SVladimir Sementsov-Ogievskiy int64_t cluster_size = block_copy_cluster_size(s->bcs);
111d003e0aeSVladimir Sementsov-Ogievskiy
112d003e0aeSVladimir Sementsov-Ogievskiy if (flags & BDRV_REQ_WRITE_UNCHANGED) {
113d003e0aeSVladimir Sementsov-Ogievskiy return 0;
114d003e0aeSVladimir Sementsov-Ogievskiy }
115d003e0aeSVladimir Sementsov-Ogievskiy
116f1bb39a8SVladimir Sementsov-Ogievskiy if (s->snapshot_error) {
117f1bb39a8SVladimir Sementsov-Ogievskiy return 0;
118f1bb39a8SVladimir Sementsov-Ogievskiy }
119f1bb39a8SVladimir Sementsov-Ogievskiy
120b518e9e9SVladimir Sementsov-Ogievskiy off = QEMU_ALIGN_DOWN(offset, cluster_size);
121b518e9e9SVladimir Sementsov-Ogievskiy end = QEMU_ALIGN_UP(offset + bytes, cluster_size);
122d003e0aeSVladimir Sementsov-Ogievskiy
1236db7fd1cSVladimir Sementsov-Ogievskiy /*
1246db7fd1cSVladimir Sementsov-Ogievskiy * Increase in_flight, so that in case of timed-out block-copy, the
1256db7fd1cSVladimir Sementsov-Ogievskiy * remaining background block_copy() request (which can't be immediately
1266db7fd1cSVladimir Sementsov-Ogievskiy * cancelled by timeout) is presented in bs->in_flight. This way we are
1276db7fd1cSVladimir Sementsov-Ogievskiy * sure that on bs close() we'll previously wait for all timed-out but yet
1286db7fd1cSVladimir Sementsov-Ogievskiy * running block_copy calls.
1296db7fd1cSVladimir Sementsov-Ogievskiy */
1306db7fd1cSVladimir Sementsov-Ogievskiy bdrv_inc_in_flight(bs);
1316db7fd1cSVladimir Sementsov-Ogievskiy ret = block_copy(s->bcs, off, end - off, true, s->cbw_timeout_ns,
1326db7fd1cSVladimir Sementsov-Ogievskiy block_copy_cb, bs);
133f1bb39a8SVladimir Sementsov-Ogievskiy if (ret < 0 && s->on_cbw_error == ON_CBW_ERROR_BREAK_GUEST_WRITE) {
134af5bcd77SVladimir Sementsov-Ogievskiy return ret;
135af5bcd77SVladimir Sementsov-Ogievskiy }
136af5bcd77SVladimir Sementsov-Ogievskiy
137af5bcd77SVladimir Sementsov-Ogievskiy WITH_QEMU_LOCK_GUARD(&s->lock) {
138f1bb39a8SVladimir Sementsov-Ogievskiy if (ret < 0) {
139f1bb39a8SVladimir Sementsov-Ogievskiy assert(s->on_cbw_error == ON_CBW_ERROR_BREAK_SNAPSHOT);
140f1bb39a8SVladimir Sementsov-Ogievskiy if (!s->snapshot_error) {
141f1bb39a8SVladimir Sementsov-Ogievskiy s->snapshot_error = ret;
142f1bb39a8SVladimir Sementsov-Ogievskiy }
143f1bb39a8SVladimir Sementsov-Ogievskiy } else {
144af5bcd77SVladimir Sementsov-Ogievskiy bdrv_set_dirty_bitmap(s->done_bitmap, off, end - off);
145f1bb39a8SVladimir Sementsov-Ogievskiy }
146af5bcd77SVladimir Sementsov-Ogievskiy reqlist_wait_all(&s->frozen_read_reqs, off, end - off, &s->lock);
147af5bcd77SVladimir Sementsov-Ogievskiy }
148af5bcd77SVladimir Sementsov-Ogievskiy
149af5bcd77SVladimir Sementsov-Ogievskiy return 0;
150d003e0aeSVladimir Sementsov-Ogievskiy }
151d003e0aeSVladimir Sementsov-Ogievskiy
1529a5a1c62SEmanuele Giuseppe Esposito static int coroutine_fn GRAPH_RDLOCK
cbw_co_pdiscard(BlockDriverState * bs,int64_t offset,int64_t bytes)1539a5a1c62SEmanuele Giuseppe Esposito cbw_co_pdiscard(BlockDriverState *bs, int64_t offset, int64_t bytes)
154d003e0aeSVladimir Sementsov-Ogievskiy {
155d003e0aeSVladimir Sementsov-Ogievskiy int ret = cbw_do_copy_before_write(bs, offset, bytes, 0);
156d003e0aeSVladimir Sementsov-Ogievskiy if (ret < 0) {
157d003e0aeSVladimir Sementsov-Ogievskiy return ret;
158d003e0aeSVladimir Sementsov-Ogievskiy }
159d003e0aeSVladimir Sementsov-Ogievskiy
1603c1e6327SVladimir Sementsov-Ogievskiy return bdrv_co_pdiscard(bs->file, offset, bytes);
161d003e0aeSVladimir Sementsov-Ogievskiy }
162d003e0aeSVladimir Sementsov-Ogievskiy
163abaf8b75SKevin Wolf static int coroutine_fn GRAPH_RDLOCK
cbw_co_pwrite_zeroes(BlockDriverState * bs,int64_t offset,int64_t bytes,BdrvRequestFlags flags)164abaf8b75SKevin Wolf cbw_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int64_t bytes,
165abaf8b75SKevin Wolf BdrvRequestFlags flags)
166d003e0aeSVladimir Sementsov-Ogievskiy {
167d003e0aeSVladimir Sementsov-Ogievskiy int ret = cbw_do_copy_before_write(bs, offset, bytes, flags);
168d003e0aeSVladimir Sementsov-Ogievskiy if (ret < 0) {
169d003e0aeSVladimir Sementsov-Ogievskiy return ret;
170d003e0aeSVladimir Sementsov-Ogievskiy }
171d003e0aeSVladimir Sementsov-Ogievskiy
1723c1e6327SVladimir Sementsov-Ogievskiy return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags);
173d003e0aeSVladimir Sementsov-Ogievskiy }
174d003e0aeSVladimir Sementsov-Ogievskiy
175b9b10c35SKevin Wolf static coroutine_fn GRAPH_RDLOCK
cbw_co_pwritev(BlockDriverState * bs,int64_t offset,int64_t bytes,QEMUIOVector * qiov,BdrvRequestFlags flags)176b9b10c35SKevin Wolf int cbw_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
177b9b10c35SKevin Wolf QEMUIOVector *qiov, BdrvRequestFlags flags)
178d003e0aeSVladimir Sementsov-Ogievskiy {
179d003e0aeSVladimir Sementsov-Ogievskiy int ret = cbw_do_copy_before_write(bs, offset, bytes, flags);
180d003e0aeSVladimir Sementsov-Ogievskiy if (ret < 0) {
181d003e0aeSVladimir Sementsov-Ogievskiy return ret;
182d003e0aeSVladimir Sementsov-Ogievskiy }
183d003e0aeSVladimir Sementsov-Ogievskiy
1843c1e6327SVladimir Sementsov-Ogievskiy return bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags);
185d003e0aeSVladimir Sementsov-Ogievskiy }
186d003e0aeSVladimir Sementsov-Ogievskiy
cbw_co_flush(BlockDriverState * bs)18788095349SEmanuele Giuseppe Esposito static int coroutine_fn GRAPH_RDLOCK cbw_co_flush(BlockDriverState *bs)
188d003e0aeSVladimir Sementsov-Ogievskiy {
1893c1e6327SVladimir Sementsov-Ogievskiy if (!bs->file) {
190d003e0aeSVladimir Sementsov-Ogievskiy return 0;
191d003e0aeSVladimir Sementsov-Ogievskiy }
192d003e0aeSVladimir Sementsov-Ogievskiy
1933c1e6327SVladimir Sementsov-Ogievskiy return bdrv_co_flush(bs->file->bs);
194d003e0aeSVladimir Sementsov-Ogievskiy }
195d003e0aeSVladimir Sementsov-Ogievskiy
196af5bcd77SVladimir Sementsov-Ogievskiy /*
197af5bcd77SVladimir Sementsov-Ogievskiy * If @offset not accessible - return NULL.
198af5bcd77SVladimir Sementsov-Ogievskiy *
199af5bcd77SVladimir Sementsov-Ogievskiy * Otherwise, set @pnum to some bytes that accessible from @file (@file is set
200af5bcd77SVladimir Sementsov-Ogievskiy * to bs->file or to s->target). Return newly allocated BlockReq object that
201af5bcd77SVladimir Sementsov-Ogievskiy * should be than passed to cbw_snapshot_read_unlock().
202af5bcd77SVladimir Sementsov-Ogievskiy *
203af5bcd77SVladimir Sementsov-Ogievskiy * It's guaranteed that guest writes will not interact in the region until
204af5bcd77SVladimir Sementsov-Ogievskiy * cbw_snapshot_read_unlock() called.
205af5bcd77SVladimir Sementsov-Ogievskiy */
2061f051dcbSKevin Wolf static BlockReq * coroutine_fn GRAPH_RDLOCK
cbw_snapshot_read_lock(BlockDriverState * bs,int64_t offset,int64_t bytes,int64_t * pnum,BdrvChild ** file)2073e614042SPaolo Bonzini cbw_snapshot_read_lock(BlockDriverState *bs, int64_t offset, int64_t bytes,
208af5bcd77SVladimir Sementsov-Ogievskiy int64_t *pnum, BdrvChild **file)
209af5bcd77SVladimir Sementsov-Ogievskiy {
210af5bcd77SVladimir Sementsov-Ogievskiy BDRVCopyBeforeWriteState *s = bs->opaque;
211af5bcd77SVladimir Sementsov-Ogievskiy BlockReq *req = g_new(BlockReq, 1);
212af5bcd77SVladimir Sementsov-Ogievskiy bool done;
213af5bcd77SVladimir Sementsov-Ogievskiy
214af5bcd77SVladimir Sementsov-Ogievskiy QEMU_LOCK_GUARD(&s->lock);
215af5bcd77SVladimir Sementsov-Ogievskiy
216f1bb39a8SVladimir Sementsov-Ogievskiy if (s->snapshot_error) {
217f1bb39a8SVladimir Sementsov-Ogievskiy g_free(req);
218f1bb39a8SVladimir Sementsov-Ogievskiy return NULL;
219f1bb39a8SVladimir Sementsov-Ogievskiy }
220f1bb39a8SVladimir Sementsov-Ogievskiy
221af5bcd77SVladimir Sementsov-Ogievskiy if (bdrv_dirty_bitmap_next_zero(s->access_bitmap, offset, bytes) != -1) {
222af5bcd77SVladimir Sementsov-Ogievskiy g_free(req);
223af5bcd77SVladimir Sementsov-Ogievskiy return NULL;
224af5bcd77SVladimir Sementsov-Ogievskiy }
225af5bcd77SVladimir Sementsov-Ogievskiy
226af5bcd77SVladimir Sementsov-Ogievskiy done = bdrv_dirty_bitmap_status(s->done_bitmap, offset, bytes, pnum);
227af5bcd77SVladimir Sementsov-Ogievskiy if (done) {
228af5bcd77SVladimir Sementsov-Ogievskiy /*
229af5bcd77SVladimir Sementsov-Ogievskiy * Special invalid BlockReq, that is handled in
230af5bcd77SVladimir Sementsov-Ogievskiy * cbw_snapshot_read_unlock(). We don't need to lock something to read
231af5bcd77SVladimir Sementsov-Ogievskiy * from s->target.
232af5bcd77SVladimir Sementsov-Ogievskiy */
233af5bcd77SVladimir Sementsov-Ogievskiy *req = (BlockReq) {.offset = -1, .bytes = -1};
234af5bcd77SVladimir Sementsov-Ogievskiy *file = s->target;
235af5bcd77SVladimir Sementsov-Ogievskiy } else {
236af5bcd77SVladimir Sementsov-Ogievskiy reqlist_init_req(&s->frozen_read_reqs, req, offset, bytes);
237af5bcd77SVladimir Sementsov-Ogievskiy *file = bs->file;
238af5bcd77SVladimir Sementsov-Ogievskiy }
239af5bcd77SVladimir Sementsov-Ogievskiy
240af5bcd77SVladimir Sementsov-Ogievskiy return req;
241af5bcd77SVladimir Sementsov-Ogievskiy }
242af5bcd77SVladimir Sementsov-Ogievskiy
2433e614042SPaolo Bonzini static coroutine_fn void
cbw_snapshot_read_unlock(BlockDriverState * bs,BlockReq * req)2443e614042SPaolo Bonzini cbw_snapshot_read_unlock(BlockDriverState *bs, BlockReq *req)
245af5bcd77SVladimir Sementsov-Ogievskiy {
246af5bcd77SVladimir Sementsov-Ogievskiy BDRVCopyBeforeWriteState *s = bs->opaque;
247af5bcd77SVladimir Sementsov-Ogievskiy
248af5bcd77SVladimir Sementsov-Ogievskiy if (req->offset == -1 && req->bytes == -1) {
249af5bcd77SVladimir Sementsov-Ogievskiy g_free(req);
250af5bcd77SVladimir Sementsov-Ogievskiy return;
251af5bcd77SVladimir Sementsov-Ogievskiy }
252af5bcd77SVladimir Sementsov-Ogievskiy
253af5bcd77SVladimir Sementsov-Ogievskiy QEMU_LOCK_GUARD(&s->lock);
254af5bcd77SVladimir Sementsov-Ogievskiy
255af5bcd77SVladimir Sementsov-Ogievskiy reqlist_remove_req(req);
256af5bcd77SVladimir Sementsov-Ogievskiy g_free(req);
257af5bcd77SVladimir Sementsov-Ogievskiy }
258af5bcd77SVladimir Sementsov-Ogievskiy
2597b9e8b22SKevin Wolf static int coroutine_fn GRAPH_RDLOCK
cbw_co_preadv_snapshot(BlockDriverState * bs,int64_t offset,int64_t bytes,QEMUIOVector * qiov,size_t qiov_offset)260af5bcd77SVladimir Sementsov-Ogievskiy cbw_co_preadv_snapshot(BlockDriverState *bs, int64_t offset, int64_t bytes,
261af5bcd77SVladimir Sementsov-Ogievskiy QEMUIOVector *qiov, size_t qiov_offset)
262af5bcd77SVladimir Sementsov-Ogievskiy {
263af5bcd77SVladimir Sementsov-Ogievskiy BlockReq *req;
264af5bcd77SVladimir Sementsov-Ogievskiy BdrvChild *file;
265af5bcd77SVladimir Sementsov-Ogievskiy int ret;
266af5bcd77SVladimir Sementsov-Ogievskiy
267af5bcd77SVladimir Sementsov-Ogievskiy /* TODO: upgrade to async loop using AioTask */
268af5bcd77SVladimir Sementsov-Ogievskiy while (bytes) {
269af5bcd77SVladimir Sementsov-Ogievskiy int64_t cur_bytes;
270af5bcd77SVladimir Sementsov-Ogievskiy
271af5bcd77SVladimir Sementsov-Ogievskiy req = cbw_snapshot_read_lock(bs, offset, bytes, &cur_bytes, &file);
272af5bcd77SVladimir Sementsov-Ogievskiy if (!req) {
273af5bcd77SVladimir Sementsov-Ogievskiy return -EACCES;
274af5bcd77SVladimir Sementsov-Ogievskiy }
275af5bcd77SVladimir Sementsov-Ogievskiy
276af5bcd77SVladimir Sementsov-Ogievskiy ret = bdrv_co_preadv_part(file, offset, cur_bytes,
277af5bcd77SVladimir Sementsov-Ogievskiy qiov, qiov_offset, 0);
278af5bcd77SVladimir Sementsov-Ogievskiy cbw_snapshot_read_unlock(bs, req);
279af5bcd77SVladimir Sementsov-Ogievskiy if (ret < 0) {
280af5bcd77SVladimir Sementsov-Ogievskiy return ret;
281af5bcd77SVladimir Sementsov-Ogievskiy }
282af5bcd77SVladimir Sementsov-Ogievskiy
283af5bcd77SVladimir Sementsov-Ogievskiy bytes -= cur_bytes;
284af5bcd77SVladimir Sementsov-Ogievskiy offset += cur_bytes;
285af5bcd77SVladimir Sementsov-Ogievskiy qiov_offset += cur_bytes;
286af5bcd77SVladimir Sementsov-Ogievskiy }
287af5bcd77SVladimir Sementsov-Ogievskiy
288af5bcd77SVladimir Sementsov-Ogievskiy return 0;
289af5bcd77SVladimir Sementsov-Ogievskiy }
290af5bcd77SVladimir Sementsov-Ogievskiy
2917b9e8b22SKevin Wolf static int coroutine_fn GRAPH_RDLOCK
cbw_co_snapshot_block_status(BlockDriverState * bs,bool want_zero,int64_t offset,int64_t bytes,int64_t * pnum,int64_t * map,BlockDriverState ** file)292af5bcd77SVladimir Sementsov-Ogievskiy cbw_co_snapshot_block_status(BlockDriverState *bs,
293af5bcd77SVladimir Sementsov-Ogievskiy bool want_zero, int64_t offset, int64_t bytes,
294af5bcd77SVladimir Sementsov-Ogievskiy int64_t *pnum, int64_t *map,
295af5bcd77SVladimir Sementsov-Ogievskiy BlockDriverState **file)
296af5bcd77SVladimir Sementsov-Ogievskiy {
297af5bcd77SVladimir Sementsov-Ogievskiy BDRVCopyBeforeWriteState *s = bs->opaque;
298af5bcd77SVladimir Sementsov-Ogievskiy BlockReq *req;
299af5bcd77SVladimir Sementsov-Ogievskiy int ret;
300af5bcd77SVladimir Sementsov-Ogievskiy int64_t cur_bytes;
301af5bcd77SVladimir Sementsov-Ogievskiy BdrvChild *child;
302af5bcd77SVladimir Sementsov-Ogievskiy
303af5bcd77SVladimir Sementsov-Ogievskiy req = cbw_snapshot_read_lock(bs, offset, bytes, &cur_bytes, &child);
304af5bcd77SVladimir Sementsov-Ogievskiy if (!req) {
305af5bcd77SVladimir Sementsov-Ogievskiy return -EACCES;
306af5bcd77SVladimir Sementsov-Ogievskiy }
307af5bcd77SVladimir Sementsov-Ogievskiy
308cc323997SPaolo Bonzini ret = bdrv_co_block_status(child->bs, offset, cur_bytes, pnum, map, file);
309af5bcd77SVladimir Sementsov-Ogievskiy if (child == s->target) {
310af5bcd77SVladimir Sementsov-Ogievskiy /*
311af5bcd77SVladimir Sementsov-Ogievskiy * We refer to s->target only for areas that we've written to it.
312af5bcd77SVladimir Sementsov-Ogievskiy * And we can not report unallocated blocks in s->target: this will
313af5bcd77SVladimir Sementsov-Ogievskiy * break generic block-status-above logic, that will go to
314af5bcd77SVladimir Sementsov-Ogievskiy * copy-before-write filtered child in this case.
315af5bcd77SVladimir Sementsov-Ogievskiy */
316af5bcd77SVladimir Sementsov-Ogievskiy assert(ret & BDRV_BLOCK_ALLOCATED);
317af5bcd77SVladimir Sementsov-Ogievskiy }
318af5bcd77SVladimir Sementsov-Ogievskiy
319af5bcd77SVladimir Sementsov-Ogievskiy cbw_snapshot_read_unlock(bs, req);
320af5bcd77SVladimir Sementsov-Ogievskiy
321af5bcd77SVladimir Sementsov-Ogievskiy return ret;
322af5bcd77SVladimir Sementsov-Ogievskiy }
323af5bcd77SVladimir Sementsov-Ogievskiy
3249a5a1c62SEmanuele Giuseppe Esposito static int coroutine_fn GRAPH_RDLOCK
cbw_co_pdiscard_snapshot(BlockDriverState * bs,int64_t offset,int64_t bytes)3259a5a1c62SEmanuele Giuseppe Esposito cbw_co_pdiscard_snapshot(BlockDriverState *bs, int64_t offset, int64_t bytes)
326af5bcd77SVladimir Sementsov-Ogievskiy {
327af5bcd77SVladimir Sementsov-Ogievskiy BDRVCopyBeforeWriteState *s = bs->opaque;
328af5bcd77SVladimir Sementsov-Ogievskiy
329af5bcd77SVladimir Sementsov-Ogievskiy WITH_QEMU_LOCK_GUARD(&s->lock) {
330af5bcd77SVladimir Sementsov-Ogievskiy bdrv_reset_dirty_bitmap(s->access_bitmap, offset, bytes);
331af5bcd77SVladimir Sementsov-Ogievskiy }
332af5bcd77SVladimir Sementsov-Ogievskiy
333af5bcd77SVladimir Sementsov-Ogievskiy block_copy_reset(s->bcs, offset, bytes);
334af5bcd77SVladimir Sementsov-Ogievskiy
335af5bcd77SVladimir Sementsov-Ogievskiy return bdrv_co_pdiscard(s->target, offset, bytes);
336af5bcd77SVladimir Sementsov-Ogievskiy }
337af5bcd77SVladimir Sementsov-Ogievskiy
cbw_refresh_filename(BlockDriverState * bs)33879a55866SKevin Wolf static void GRAPH_RDLOCK cbw_refresh_filename(BlockDriverState *bs)
339d003e0aeSVladimir Sementsov-Ogievskiy {
340d003e0aeSVladimir Sementsov-Ogievskiy pstrcpy(bs->exact_filename, sizeof(bs->exact_filename),
3413c1e6327SVladimir Sementsov-Ogievskiy bs->file->bs->filename);
342d003e0aeSVladimir Sementsov-Ogievskiy }
343d003e0aeSVladimir Sementsov-Ogievskiy
344c629b6d2SKevin Wolf static void GRAPH_RDLOCK
cbw_child_perm(BlockDriverState * bs,BdrvChild * c,BdrvChildRole role,BlockReopenQueue * reopen_queue,uint64_t perm,uint64_t shared,uint64_t * nperm,uint64_t * nshared)345c629b6d2SKevin Wolf cbw_child_perm(BlockDriverState *bs, BdrvChild *c, BdrvChildRole role,
346d003e0aeSVladimir Sementsov-Ogievskiy BlockReopenQueue *reopen_queue,
347d003e0aeSVladimir Sementsov-Ogievskiy uint64_t perm, uint64_t shared,
348d003e0aeSVladimir Sementsov-Ogievskiy uint64_t *nperm, uint64_t *nshared)
349d003e0aeSVladimir Sementsov-Ogievskiy {
350d003e0aeSVladimir Sementsov-Ogievskiy if (!(role & BDRV_CHILD_FILTERED)) {
351d003e0aeSVladimir Sementsov-Ogievskiy /*
352d003e0aeSVladimir Sementsov-Ogievskiy * Target child
353d003e0aeSVladimir Sementsov-Ogievskiy *
354d003e0aeSVladimir Sementsov-Ogievskiy * Share write to target (child_file), to not interfere
355d003e0aeSVladimir Sementsov-Ogievskiy * with guest writes to its disk which may be in target backing chain.
356d003e0aeSVladimir Sementsov-Ogievskiy * Can't resize during a backup block job because we check the size
357d003e0aeSVladimir Sementsov-Ogievskiy * only upfront.
358d003e0aeSVladimir Sementsov-Ogievskiy */
359d003e0aeSVladimir Sementsov-Ogievskiy *nshared = BLK_PERM_ALL & ~BLK_PERM_RESIZE;
360d003e0aeSVladimir Sementsov-Ogievskiy *nperm = BLK_PERM_WRITE;
361d003e0aeSVladimir Sementsov-Ogievskiy } else {
362d003e0aeSVladimir Sementsov-Ogievskiy /* Source child */
363d003e0aeSVladimir Sementsov-Ogievskiy bdrv_default_perms(bs, c, role, reopen_queue,
364d003e0aeSVladimir Sementsov-Ogievskiy perm, shared, nperm, nshared);
365d003e0aeSVladimir Sementsov-Ogievskiy
3663860c020SVladimir Sementsov-Ogievskiy if (!QLIST_EMPTY(&bs->parents)) {
367d003e0aeSVladimir Sementsov-Ogievskiy if (perm & BLK_PERM_WRITE) {
368d003e0aeSVladimir Sementsov-Ogievskiy *nperm = *nperm | BLK_PERM_CONSISTENT_READ;
369d003e0aeSVladimir Sementsov-Ogievskiy }
370d003e0aeSVladimir Sementsov-Ogievskiy *nshared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
371d003e0aeSVladimir Sementsov-Ogievskiy }
372d003e0aeSVladimir Sementsov-Ogievskiy }
3733860c020SVladimir Sementsov-Ogievskiy }
374d003e0aeSVladimir Sementsov-Ogievskiy
cbw_parse_options(QDict * options,Error ** errp)37579ef0cebSVladimir Sementsov-Ogievskiy static BlockdevOptions *cbw_parse_options(QDict *options, Error **errp)
3765f3a3cd7SVladimir Sementsov-Ogievskiy {
37779ef0cebSVladimir Sementsov-Ogievskiy BlockdevOptions *opts = NULL;
3785f3a3cd7SVladimir Sementsov-Ogievskiy Visitor *v = NULL;
3795f3a3cd7SVladimir Sementsov-Ogievskiy
38079ef0cebSVladimir Sementsov-Ogievskiy qdict_put_str(options, "driver", "copy-before-write");
3815f3a3cd7SVladimir Sementsov-Ogievskiy
38279ef0cebSVladimir Sementsov-Ogievskiy v = qobject_input_visitor_new_flat_confused(options, errp);
3835f3a3cd7SVladimir Sementsov-Ogievskiy if (!v) {
3845f3a3cd7SVladimir Sementsov-Ogievskiy goto out;
3855f3a3cd7SVladimir Sementsov-Ogievskiy }
3865f3a3cd7SVladimir Sementsov-Ogievskiy
38779ef0cebSVladimir Sementsov-Ogievskiy visit_type_BlockdevOptions(v, NULL, &opts, errp);
38879ef0cebSVladimir Sementsov-Ogievskiy if (!opts) {
3895f3a3cd7SVladimir Sementsov-Ogievskiy goto out;
3905f3a3cd7SVladimir Sementsov-Ogievskiy }
3915f3a3cd7SVladimir Sementsov-Ogievskiy
39279ef0cebSVladimir Sementsov-Ogievskiy /*
39379ef0cebSVladimir Sementsov-Ogievskiy * Delete options which we are going to parse through BlockdevOptions
39479ef0cebSVladimir Sementsov-Ogievskiy * object for original options.
39579ef0cebSVladimir Sementsov-Ogievskiy */
39679ef0cebSVladimir Sementsov-Ogievskiy qdict_extract_subqdict(options, NULL, "bitmap");
397f1bb39a8SVladimir Sementsov-Ogievskiy qdict_del(options, "on-cbw-error");
3986db7fd1cSVladimir Sementsov-Ogievskiy qdict_del(options, "cbw-timeout");
3995f3a3cd7SVladimir Sementsov-Ogievskiy
4005f3a3cd7SVladimir Sementsov-Ogievskiy out:
4015f3a3cd7SVladimir Sementsov-Ogievskiy visit_free(v);
40279ef0cebSVladimir Sementsov-Ogievskiy qdict_del(options, "driver");
4035f3a3cd7SVladimir Sementsov-Ogievskiy
40479ef0cebSVladimir Sementsov-Ogievskiy return opts;
4055f3a3cd7SVladimir Sementsov-Ogievskiy }
4065f3a3cd7SVladimir Sementsov-Ogievskiy
cbw_open(BlockDriverState * bs,QDict * options,int flags,Error ** errp)407751cec7aSVladimir Sementsov-Ogievskiy static int cbw_open(BlockDriverState *bs, QDict *options, int flags,
408751cec7aSVladimir Sementsov-Ogievskiy Error **errp)
4091f0cacb9SVladimir Sementsov-Ogievskiy {
410c79eabc5SZhao Liu ERRP_GUARD();
411fe7ea40cSVladimir Sementsov-Ogievskiy BDRVCopyBeforeWriteState *s = bs->opaque;
4125f3a3cd7SVladimir Sementsov-Ogievskiy BdrvDirtyBitmap *bitmap = NULL;
413af5bcd77SVladimir Sementsov-Ogievskiy int64_t cluster_size;
41479ef0cebSVladimir Sementsov-Ogievskiy g_autoptr(BlockdevOptions) full_opts = NULL;
41579ef0cebSVladimir Sementsov-Ogievskiy BlockdevOptionsCbw *opts;
41683930780SVladimir Sementsov-Ogievskiy int ret;
41779ef0cebSVladimir Sementsov-Ogievskiy
41879ef0cebSVladimir Sementsov-Ogievskiy full_opts = cbw_parse_options(options, errp);
41979ef0cebSVladimir Sementsov-Ogievskiy if (!full_opts) {
42079ef0cebSVladimir Sementsov-Ogievskiy return -EINVAL;
42179ef0cebSVladimir Sementsov-Ogievskiy }
42279ef0cebSVladimir Sementsov-Ogievskiy assert(full_opts->driver == BLOCKDEV_DRIVER_COPY_BEFORE_WRITE);
42379ef0cebSVladimir Sementsov-Ogievskiy opts = &full_opts->u.copy_before_write;
4241f0cacb9SVladimir Sementsov-Ogievskiy
42583930780SVladimir Sementsov-Ogievskiy ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
42683930780SVladimir Sementsov-Ogievskiy if (ret < 0) {
42783930780SVladimir Sementsov-Ogievskiy return ret;
4281f0cacb9SVladimir Sementsov-Ogievskiy }
4291f0cacb9SVladimir Sementsov-Ogievskiy
430f44fd739SVladimir Sementsov-Ogievskiy s->target = bdrv_open_child(NULL, options, "target", bs, &child_of_bds,
431f44fd739SVladimir Sementsov-Ogievskiy BDRV_CHILD_DATA, false, errp);
432f44fd739SVladimir Sementsov-Ogievskiy if (!s->target) {
4331f0cacb9SVladimir Sementsov-Ogievskiy return -EINVAL;
4341f0cacb9SVladimir Sementsov-Ogievskiy }
4351f0cacb9SVladimir Sementsov-Ogievskiy
436a4b740dbSKevin Wolf GRAPH_RDLOCK_GUARD_MAINLOOP();
437a4b740dbSKevin Wolf
43854fde4ffSMarkus Armbruster if (opts->bitmap) {
43979ef0cebSVladimir Sementsov-Ogievskiy bitmap = block_dirty_bitmap_lookup(opts->bitmap->node,
44079ef0cebSVladimir Sementsov-Ogievskiy opts->bitmap->name, NULL, errp);
44179ef0cebSVladimir Sementsov-Ogievskiy if (!bitmap) {
442b49f4755SStefan Hajnoczi return -EINVAL;
4435f3a3cd7SVladimir Sementsov-Ogievskiy }
44479ef0cebSVladimir Sementsov-Ogievskiy }
445f1bb39a8SVladimir Sementsov-Ogievskiy s->on_cbw_error = opts->has_on_cbw_error ? opts->on_cbw_error :
446f1bb39a8SVladimir Sementsov-Ogievskiy ON_CBW_ERROR_BREAK_GUEST_WRITE;
4476db7fd1cSVladimir Sementsov-Ogievskiy s->cbw_timeout_ns = opts->has_cbw_timeout ?
4486db7fd1cSVladimir Sementsov-Ogievskiy opts->cbw_timeout * NANOSECONDS_PER_SECOND : 0;
4495f3a3cd7SVladimir Sementsov-Ogievskiy
4505a507426SVladimir Sementsov-Ogievskiy bs->total_sectors = bs->file->bs->total_sectors;
4515a507426SVladimir Sementsov-Ogievskiy bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED |
4525a507426SVladimir Sementsov-Ogievskiy (BDRV_REQ_FUA & bs->file->bs->supported_write_flags);
4535a507426SVladimir Sementsov-Ogievskiy bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED |
4545a507426SVladimir Sementsov-Ogievskiy ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
4555a507426SVladimir Sementsov-Ogievskiy bs->file->bs->supported_zero_flags);
4565a507426SVladimir Sementsov-Ogievskiy
4575f3a3cd7SVladimir Sementsov-Ogievskiy s->bcs = block_copy_state_new(bs->file, s->target, bitmap, errp);
458fe7ea40cSVladimir Sementsov-Ogievskiy if (!s->bcs) {
4591f0cacb9SVladimir Sementsov-Ogievskiy error_prepend(errp, "Cannot create block-copy-state: ");
460b49f4755SStefan Hajnoczi return -EINVAL;
4611f0cacb9SVladimir Sementsov-Ogievskiy }
4621f0cacb9SVladimir Sementsov-Ogievskiy
463af5bcd77SVladimir Sementsov-Ogievskiy cluster_size = block_copy_cluster_size(s->bcs);
464af5bcd77SVladimir Sementsov-Ogievskiy
465af5bcd77SVladimir Sementsov-Ogievskiy s->done_bitmap = bdrv_create_dirty_bitmap(bs, cluster_size, NULL, errp);
466af5bcd77SVladimir Sementsov-Ogievskiy if (!s->done_bitmap) {
467b49f4755SStefan Hajnoczi return -EINVAL;
468af5bcd77SVladimir Sementsov-Ogievskiy }
469af5bcd77SVladimir Sementsov-Ogievskiy bdrv_disable_dirty_bitmap(s->done_bitmap);
470af5bcd77SVladimir Sementsov-Ogievskiy
471af5bcd77SVladimir Sementsov-Ogievskiy /* s->access_bitmap starts equal to bcs bitmap */
472af5bcd77SVladimir Sementsov-Ogievskiy s->access_bitmap = bdrv_create_dirty_bitmap(bs, cluster_size, NULL, errp);
473af5bcd77SVladimir Sementsov-Ogievskiy if (!s->access_bitmap) {
474b49f4755SStefan Hajnoczi return -EINVAL;
475af5bcd77SVladimir Sementsov-Ogievskiy }
476af5bcd77SVladimir Sementsov-Ogievskiy bdrv_disable_dirty_bitmap(s->access_bitmap);
477af5bcd77SVladimir Sementsov-Ogievskiy bdrv_dirty_bitmap_merge_internal(s->access_bitmap,
478af5bcd77SVladimir Sementsov-Ogievskiy block_copy_dirty_bitmap(s->bcs), NULL,
479af5bcd77SVladimir Sementsov-Ogievskiy true);
480af5bcd77SVladimir Sementsov-Ogievskiy
481af5bcd77SVladimir Sementsov-Ogievskiy qemu_co_mutex_init(&s->lock);
482af5bcd77SVladimir Sementsov-Ogievskiy QLIST_INIT(&s->frozen_read_reqs);
483b49f4755SStefan Hajnoczi return 0;
4841f0cacb9SVladimir Sementsov-Ogievskiy }
4851f0cacb9SVladimir Sementsov-Ogievskiy
cbw_close(BlockDriverState * bs)486751cec7aSVladimir Sementsov-Ogievskiy static void cbw_close(BlockDriverState *bs)
487751cec7aSVladimir Sementsov-Ogievskiy {
488751cec7aSVladimir Sementsov-Ogievskiy BDRVCopyBeforeWriteState *s = bs->opaque;
489751cec7aSVladimir Sementsov-Ogievskiy
490af5bcd77SVladimir Sementsov-Ogievskiy bdrv_release_dirty_bitmap(s->access_bitmap);
491af5bcd77SVladimir Sementsov-Ogievskiy bdrv_release_dirty_bitmap(s->done_bitmap);
492af5bcd77SVladimir Sementsov-Ogievskiy
493751cec7aSVladimir Sementsov-Ogievskiy block_copy_state_free(s->bcs);
494751cec7aSVladimir Sementsov-Ogievskiy s->bcs = NULL;
495751cec7aSVladimir Sementsov-Ogievskiy }
496751cec7aSVladimir Sementsov-Ogievskiy
4979ea473fbSKevin Wolf static BlockDriver bdrv_cbw_filter = {
498d003e0aeSVladimir Sementsov-Ogievskiy .format_name = "copy-before-write",
499d003e0aeSVladimir Sementsov-Ogievskiy .instance_size = sizeof(BDRVCopyBeforeWriteState),
500d003e0aeSVladimir Sementsov-Ogievskiy
501751cec7aSVladimir Sementsov-Ogievskiy .bdrv_open = cbw_open,
502751cec7aSVladimir Sementsov-Ogievskiy .bdrv_close = cbw_close,
503751cec7aSVladimir Sementsov-Ogievskiy
504d003e0aeSVladimir Sementsov-Ogievskiy .bdrv_co_preadv = cbw_co_preadv,
505d003e0aeSVladimir Sementsov-Ogievskiy .bdrv_co_pwritev = cbw_co_pwritev,
506d003e0aeSVladimir Sementsov-Ogievskiy .bdrv_co_pwrite_zeroes = cbw_co_pwrite_zeroes,
507d003e0aeSVladimir Sementsov-Ogievskiy .bdrv_co_pdiscard = cbw_co_pdiscard,
508d003e0aeSVladimir Sementsov-Ogievskiy .bdrv_co_flush = cbw_co_flush,
509d003e0aeSVladimir Sementsov-Ogievskiy
510af5bcd77SVladimir Sementsov-Ogievskiy .bdrv_co_preadv_snapshot = cbw_co_preadv_snapshot,
511af5bcd77SVladimir Sementsov-Ogievskiy .bdrv_co_pdiscard_snapshot = cbw_co_pdiscard_snapshot,
512af5bcd77SVladimir Sementsov-Ogievskiy .bdrv_co_snapshot_block_status = cbw_co_snapshot_block_status,
513af5bcd77SVladimir Sementsov-Ogievskiy
514d003e0aeSVladimir Sementsov-Ogievskiy .bdrv_refresh_filename = cbw_refresh_filename,
515d003e0aeSVladimir Sementsov-Ogievskiy
516d003e0aeSVladimir Sementsov-Ogievskiy .bdrv_child_perm = cbw_child_perm,
517d003e0aeSVladimir Sementsov-Ogievskiy
518d003e0aeSVladimir Sementsov-Ogievskiy .is_filter = true,
519d003e0aeSVladimir Sementsov-Ogievskiy };
520d003e0aeSVladimir Sementsov-Ogievskiy
bdrv_cbw_append(BlockDriverState * source,BlockDriverState * target,const char * filter_node_name,BlockCopyState ** bcs,Error ** errp)521d003e0aeSVladimir Sementsov-Ogievskiy BlockDriverState *bdrv_cbw_append(BlockDriverState *source,
522d003e0aeSVladimir Sementsov-Ogievskiy BlockDriverState *target,
523d003e0aeSVladimir Sementsov-Ogievskiy const char *filter_node_name,
524d003e0aeSVladimir Sementsov-Ogievskiy BlockCopyState **bcs,
525d003e0aeSVladimir Sementsov-Ogievskiy Error **errp)
526d003e0aeSVladimir Sementsov-Ogievskiy {
527d003e0aeSVladimir Sementsov-Ogievskiy BDRVCopyBeforeWriteState *state;
528d003e0aeSVladimir Sementsov-Ogievskiy BlockDriverState *top;
529f44fd739SVladimir Sementsov-Ogievskiy QDict *opts;
530d003e0aeSVladimir Sementsov-Ogievskiy
531d003e0aeSVladimir Sementsov-Ogievskiy assert(source->total_sectors == target->total_sectors);
532377cc15bSEmanuele Giuseppe Esposito GLOBAL_STATE_CODE();
533d003e0aeSVladimir Sementsov-Ogievskiy
534f44fd739SVladimir Sementsov-Ogievskiy opts = qdict_new();
535751cec7aSVladimir Sementsov-Ogievskiy qdict_put_str(opts, "driver", "copy-before-write");
536751cec7aSVladimir Sementsov-Ogievskiy if (filter_node_name) {
537751cec7aSVladimir Sementsov-Ogievskiy qdict_put_str(opts, "node-name", filter_node_name);
538751cec7aSVladimir Sementsov-Ogievskiy }
539f44fd739SVladimir Sementsov-Ogievskiy qdict_put_str(opts, "file", bdrv_get_node_name(source));
540f44fd739SVladimir Sementsov-Ogievskiy qdict_put_str(opts, "target", bdrv_get_node_name(target));
541f44fd739SVladimir Sementsov-Ogievskiy
542751cec7aSVladimir Sementsov-Ogievskiy top = bdrv_insert_node(source, opts, BDRV_O_RDWR, errp);
543751cec7aSVladimir Sementsov-Ogievskiy if (!top) {
544751cec7aSVladimir Sementsov-Ogievskiy return NULL;
545d003e0aeSVladimir Sementsov-Ogievskiy }
546d003e0aeSVladimir Sementsov-Ogievskiy
547751cec7aSVladimir Sementsov-Ogievskiy state = top->opaque;
5487ddbce2dSVladimir Sementsov-Ogievskiy *bcs = state->bcs;
549d003e0aeSVladimir Sementsov-Ogievskiy
550d003e0aeSVladimir Sementsov-Ogievskiy return top;
551d003e0aeSVladimir Sementsov-Ogievskiy }
552d003e0aeSVladimir Sementsov-Ogievskiy
bdrv_cbw_drop(BlockDriverState * bs)553d003e0aeSVladimir Sementsov-Ogievskiy void bdrv_cbw_drop(BlockDriverState *bs)
554d003e0aeSVladimir Sementsov-Ogievskiy {
555377cc15bSEmanuele Giuseppe Esposito GLOBAL_STATE_CODE();
556d003e0aeSVladimir Sementsov-Ogievskiy bdrv_drop_filter(bs, &error_abort);
557d003e0aeSVladimir Sementsov-Ogievskiy bdrv_unref(bs);
558d003e0aeSVladimir Sementsov-Ogievskiy }
559751cec7aSVladimir Sementsov-Ogievskiy
cbw_init(void)560751cec7aSVladimir Sementsov-Ogievskiy static void cbw_init(void)
561751cec7aSVladimir Sementsov-Ogievskiy {
562751cec7aSVladimir Sementsov-Ogievskiy bdrv_register(&bdrv_cbw_filter);
563751cec7aSVladimir Sementsov-Ogievskiy }
564751cec7aSVladimir Sementsov-Ogievskiy
565751cec7aSVladimir Sementsov-Ogievskiy block_init(cbw_init);
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