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Commit | Line | Data |
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4f1043b4 SH |
1 | /* |
2 | * Image streaming | |
3 | * | |
4 | * Copyright IBM, Corp. 2011 | |
5 | * | |
6 | * Authors: | |
7 | * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> | |
8 | * | |
9 | * This work is licensed under the terms of the GNU LGPL, version 2 or later. | |
10 | * See the COPYING.LIB file in the top-level directory. | |
11 | * | |
12 | */ | |
13 | ||
80c71a24 | 14 | #include "qemu/osdep.h" |
4f1043b4 | 15 | #include "trace.h" |
737e150e | 16 | #include "block/block_int.h" |
c87621ea | 17 | #include "block/blockjob_int.h" |
da34e65c | 18 | #include "qapi/error.h" |
205736f4 | 19 | #include "qapi/qmp/qdict.h" |
6ef228fc | 20 | #include "qemu/ratelimit.h" |
373340b2 | 21 | #include "sysemu/block-backend.h" |
205736f4 | 22 | #include "block/copy-on-read.h" |
4f1043b4 SH |
23 | |
24 | enum { | |
25 | /* | |
99136607 VSO |
26 | * Maximum chunk size to feed to copy-on-read. This should be |
27 | * large enough to process multiple clusters in a single call, so | |
28 | * that populating contiguous regions of the image is efficient. | |
4f1043b4 | 29 | */ |
99136607 | 30 | STREAM_CHUNK = 512 * 1024, /* in bytes */ |
4f1043b4 SH |
31 | }; |
32 | ||
33 | typedef struct StreamBlockJob { | |
34 | BlockJob common; | |
048954e2 | 35 | BlockBackend *blk; |
67acfd21 HR |
36 | BlockDriverState *base_overlay; /* COW overlay (stream from this) */ |
37 | BlockDriverState *above_base; /* Node directly above the base */ | |
205736f4 | 38 | BlockDriverState *cor_filter_bs; |
0f6c9498 | 39 | BlockDriverState *target_bs; |
1d809098 | 40 | BlockdevOnError on_error; |
13d8cc51 | 41 | char *backing_file_str; |
e7d22f8b | 42 | bool bs_read_only; |
4f1043b4 SH |
43 | } StreamBlockJob; |
44 | ||
03e35d82 | 45 | static int coroutine_fn stream_populate(BlockBackend *blk, |
99136607 | 46 | int64_t offset, uint64_t bytes) |
4f1043b4 | 47 | { |
8493211c | 48 | assert(bytes < SIZE_MAX); |
4f1043b4 | 49 | |
205736f4 | 50 | return blk_co_preadv(blk, offset, bytes, NULL, BDRV_REQ_PREFETCH); |
65854933 AG |
51 | } |
52 | ||
1b57488a | 53 | static int stream_prepare(Job *job) |
f3e69beb | 54 | { |
1908a559 | 55 | StreamBlockJob *s = container_of(job, StreamBlockJob, common.job); |
0f6c9498 | 56 | BlockDriverState *unfiltered_bs = bdrv_skip_filters(s->target_bs); |
8d3dd037 HR |
57 | BlockDriverState *base; |
58 | BlockDriverState *unfiltered_base; | |
12fa4af6 | 59 | Error *local_err = NULL; |
1b57488a | 60 | int ret = 0; |
f3e69beb | 61 | |
205736f4 AS |
62 | /* We should drop filter at this point, as filter hold the backing chain */ |
63 | bdrv_cor_filter_drop(s->cor_filter_bs); | |
64 | s->cor_filter_bs = NULL; | |
65854933 | 65 | |
92140b9f KW |
66 | /* |
67 | * bdrv_set_backing_hd() requires that unfiltered_bs is drained. Drain | |
68 | * already here and use bdrv_set_backing_hd_drained() instead because | |
69 | * the polling during drained_begin() might change the graph, and if we do | |
70 | * this only later, we may end up working with the wrong base node (or it | |
71 | * might even have gone away by the time we want to use it). | |
72 | */ | |
73 | bdrv_drained_begin(unfiltered_bs); | |
b1e1af39 | 74 | |
8d3dd037 HR |
75 | base = bdrv_filter_or_cow_bs(s->above_base); |
76 | unfiltered_base = bdrv_skip_filters(base); | |
77 | ||
67acfd21 | 78 | if (bdrv_cow_child(unfiltered_bs)) { |
f3e69beb | 79 | const char *base_id = NULL, *base_fmt = NULL; |
000e5a1c AS |
80 | if (unfiltered_base) { |
81 | base_id = s->backing_file_str ?: unfiltered_base->filename; | |
82 | if (unfiltered_base->drv) { | |
83 | base_fmt = unfiltered_base->drv->format_name; | |
f3e69beb SH |
84 | } |
85 | } | |
b1e1af39 | 86 | |
92140b9f KW |
87 | bdrv_set_backing_hd_drained(unfiltered_bs, base, &local_err); |
88 | ||
89 | /* | |
90 | * This call will do I/O, so the graph can change again from here on. | |
91 | * We have already completed the graph change, so we are not in danger | |
92 | * of operating on the wrong node any more if this happens. | |
93 | */ | |
67acfd21 | 94 | ret = bdrv_change_backing_file(unfiltered_bs, base_id, base_fmt, false); |
12fa4af6 KW |
95 | if (local_err) { |
96 | error_report_err(local_err); | |
b1e1af39 HR |
97 | ret = -EPERM; |
98 | goto out; | |
12fa4af6 | 99 | } |
f3e69beb SH |
100 | } |
101 | ||
b1e1af39 | 102 | out: |
92140b9f | 103 | bdrv_drained_end(unfiltered_bs); |
1b57488a JS |
104 | return ret; |
105 | } | |
106 | ||
107 | static void stream_clean(Job *job) | |
108 | { | |
109 | StreamBlockJob *s = container_of(job, StreamBlockJob, common.job); | |
1b57488a | 110 | |
205736f4 AS |
111 | if (s->cor_filter_bs) { |
112 | bdrv_cor_filter_drop(s->cor_filter_bs); | |
113 | s->cor_filter_bs = NULL; | |
114 | } | |
115 | ||
048954e2 VSO |
116 | blk_unref(s->blk); |
117 | s->blk = NULL; | |
118 | ||
61b49e48 | 119 | /* Reopen the image back in read-only mode if necessary */ |
e7d22f8b | 120 | if (s->bs_read_only) { |
a170a91f | 121 | /* Give up write permissions before making it read-only */ |
0f6c9498 | 122 | bdrv_reopen_set_read_only(s->target_bs, true, NULL); |
61b49e48 AG |
123 | } |
124 | ||
f3e69beb | 125 | g_free(s->backing_file_str); |
f3e69beb SH |
126 | } |
127 | ||
f67432a2 | 128 | static int coroutine_fn stream_run(Job *job, Error **errp) |
4f1043b4 | 129 | { |
f67432a2 | 130 | StreamBlockJob *s = container_of(job, StreamBlockJob, common.job); |
0f6c9498 | 131 | BlockDriverState *unfiltered_bs = bdrv_skip_filters(s->target_bs); |
05df8a6a | 132 | int64_t len; |
d535435f | 133 | int64_t offset = 0; |
1d809098 | 134 | int error = 0; |
51b0a488 | 135 | int64_t n = 0; /* bytes */ |
4f1043b4 | 136 | |
67acfd21 | 137 | if (unfiltered_bs == s->base_overlay) { |
c624b015 | 138 | /* Nothing to stream */ |
96a07d5b | 139 | return 0; |
f4a193e7 HR |
140 | } |
141 | ||
8ab8140a KW |
142 | WITH_GRAPH_RDLOCK_GUARD() { |
143 | len = bdrv_co_getlength(s->target_bs); | |
144 | if (len < 0) { | |
145 | return len; | |
146 | } | |
4f1043b4 | 147 | } |
30a5c887 | 148 | job_progress_set_remaining(&s->common.job, len); |
4f1043b4 | 149 | |
05df8a6a | 150 | for ( ; offset < len; offset += n) { |
f9749f28 | 151 | bool copy; |
35c94535 | 152 | int ret; |
4513eafe | 153 | |
4513eafe | 154 | /* Note that even when no rate limit is applied we need to yield |
c57b6656 | 155 | * with no pending I/O here so that bdrv_drain_all() returns. |
4513eafe | 156 | */ |
018e5987 | 157 | block_job_ratelimit_sleep(&s->common); |
daa7f2f9 | 158 | if (job_is_cancelled(&s->common.job)) { |
4f1043b4 SH |
159 | break; |
160 | } | |
161 | ||
c3e4f43a SW |
162 | copy = false; |
163 | ||
7ff9579e KW |
164 | WITH_GRAPH_RDLOCK_GUARD() { |
165 | ret = bdrv_is_allocated(unfiltered_bs, offset, STREAM_CHUNK, &n); | |
166 | if (ret == 1) { | |
167 | /* Allocated in the top, no need to copy. */ | |
168 | } else if (ret >= 0) { | |
169 | /* | |
170 | * Copy if allocated in the intermediate images. Limit to the | |
171 | * known-unallocated area [offset, offset+n*BDRV_SECTOR_SIZE). | |
172 | */ | |
173 | ret = bdrv_is_allocated_above(bdrv_cow_bs(unfiltered_bs), | |
174 | s->base_overlay, true, | |
175 | offset, n, &n); | |
176 | /* Finish early if end of backing file has been reached */ | |
177 | if (ret == 0 && n == 0) { | |
178 | n = len - offset; | |
179 | } | |
180 | ||
181 | copy = (ret > 0); | |
571cd9dc | 182 | } |
f9749f28 | 183 | } |
51b0a488 | 184 | trace_stream_one_iteration(s, offset, n, ret); |
c3e4f43a | 185 | if (copy) { |
048954e2 | 186 | ret = stream_populate(s->blk, offset, n); |
4f1043b4 SH |
187 | } |
188 | if (ret < 0) { | |
1d809098 | 189 | BlockErrorAction action = |
81e254dc | 190 | block_job_error_action(&s->common, s->on_error, true, -ret); |
a589569f | 191 | if (action == BLOCK_ERROR_ACTION_STOP) { |
1d809098 PB |
192 | n = 0; |
193 | continue; | |
194 | } | |
195 | if (error == 0) { | |
196 | error = ret; | |
197 | } | |
a589569f | 198 | if (action == BLOCK_ERROR_ACTION_REPORT) { |
1d809098 PB |
199 | break; |
200 | } | |
4f1043b4 SH |
201 | } |
202 | ||
203 | /* Publish progress */ | |
30a5c887 | 204 | job_progress_update(&s->common.job, n); |
dee81d51 | 205 | if (copy) { |
018e5987 | 206 | block_job_ratelimit_processed_bytes(&s->common, n); |
f14a39cc | 207 | } |
4f1043b4 SH |
208 | } |
209 | ||
96a07d5b AS |
210 | /* Do not remove the backing file if an error was there but ignored. */ |
211 | return error; | |
4f1043b4 SH |
212 | } |
213 | ||
3fc4b10a | 214 | static const BlockJobDriver stream_job_driver = { |
33e9e9bd KW |
215 | .job_driver = { |
216 | .instance_size = sizeof(StreamBlockJob), | |
252291ea | 217 | .job_type = JOB_TYPE_STREAM, |
80fa2c75 | 218 | .free = block_job_free, |
f67432a2 | 219 | .run = stream_run, |
1b57488a JS |
220 | .prepare = stream_prepare, |
221 | .clean = stream_clean, | |
b15de828 | 222 | .user_resume = block_job_user_resume, |
33e9e9bd | 223 | }, |
4f1043b4 SH |
224 | }; |
225 | ||
2323322e AG |
226 | void stream_start(const char *job_id, BlockDriverState *bs, |
227 | BlockDriverState *base, const char *backing_file_str, | |
7f4a396d | 228 | BlockDriverState *bottom, |
cf6320df | 229 | int creation_flags, int64_t speed, |
880747a8 AS |
230 | BlockdevOnError on_error, |
231 | const char *filter_node_name, | |
232 | Error **errp) | |
4f1043b4 | 233 | { |
1bf26076 | 234 | StreamBlockJob *s = NULL; |
61b49e48 | 235 | BlockDriverState *iter; |
e7d22f8b | 236 | bool bs_read_only; |
c624b015 | 237 | int basic_flags = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED; |
7f4a396d | 238 | BlockDriverState *base_overlay; |
205736f4 | 239 | BlockDriverState *cor_filter_bs = NULL; |
67acfd21 | 240 | BlockDriverState *above_base; |
205736f4 | 241 | QDict *opts; |
1bf26076 | 242 | int ret; |
4f1043b4 | 243 | |
b4ad82aa EGE |
244 | GLOBAL_STATE_CODE(); |
245 | ||
7f4a396d VSO |
246 | assert(!(base && bottom)); |
247 | assert(!(backing_file_str && bottom)); | |
248 | ||
249 | if (bottom) { | |
250 | /* | |
251 | * New simple interface. The code is written in terms of old interface | |
252 | * with @base parameter (still, it doesn't freeze link to base, so in | |
253 | * this mean old code is correct for new interface). So, for now, just | |
254 | * emulate base_overlay and above_base. Still, when old interface | |
255 | * finally removed, we should refactor code to use only "bottom", but | |
256 | * not "*base*" things. | |
257 | */ | |
258 | assert(!bottom->drv->is_filter); | |
259 | base_overlay = above_base = bottom; | |
260 | } else { | |
261 | base_overlay = bdrv_find_overlay(bs, base); | |
262 | if (!base_overlay) { | |
263 | error_setg(errp, "'%s' is not in the backing chain of '%s'", | |
264 | base->node_name, bs->node_name); | |
265 | return; | |
266 | } | |
67acfd21 | 267 | |
7f4a396d VSO |
268 | /* |
269 | * Find the node directly above @base. @base_overlay is a COW overlay, | |
270 | * so it must have a bdrv_cow_child(), but it is the immediate overlay | |
271 | * of @base, so between the two there can only be filters. | |
272 | */ | |
273 | above_base = base_overlay; | |
274 | if (bdrv_cow_bs(above_base) != base) { | |
275 | above_base = bdrv_cow_bs(above_base); | |
276 | while (bdrv_filter_bs(above_base) != base) { | |
277 | above_base = bdrv_filter_bs(above_base); | |
278 | } | |
67acfd21 HR |
279 | } |
280 | } | |
281 | ||
61b49e48 | 282 | /* Make sure that the image is opened in read-write mode */ |
e7d22f8b AG |
283 | bs_read_only = bdrv_is_read_only(bs); |
284 | if (bs_read_only) { | |
205736f4 AS |
285 | int ret; |
286 | /* Hold the chain during reopen */ | |
287 | if (bdrv_freeze_backing_chain(bs, above_base, errp) < 0) { | |
288 | return; | |
289 | } | |
290 | ||
291 | ret = bdrv_reopen_set_read_only(bs, false, errp); | |
292 | ||
293 | /* failure, or cor-filter will hold the chain */ | |
294 | bdrv_unfreeze_backing_chain(bs, above_base); | |
295 | ||
296 | if (ret < 0) { | |
297 | return; | |
61b49e48 AG |
298 | } |
299 | } | |
300 | ||
205736f4 AS |
301 | opts = qdict_new(); |
302 | ||
303 | qdict_put_str(opts, "driver", "copy-on-read"); | |
304 | qdict_put_str(opts, "file", bdrv_get_node_name(bs)); | |
305 | /* Pass the base_overlay node name as 'bottom' to COR driver */ | |
306 | qdict_put_str(opts, "bottom", base_overlay->node_name); | |
307 | if (filter_node_name) { | |
308 | qdict_put_str(opts, "node-name", filter_node_name); | |
309 | } | |
310 | ||
311 | cor_filter_bs = bdrv_insert_node(bs, opts, BDRV_O_RDWR, errp); | |
312 | if (!cor_filter_bs) { | |
313 | goto fail; | |
314 | } | |
315 | ||
316 | if (!filter_node_name) { | |
317 | cor_filter_bs->implicit = true; | |
318 | } | |
319 | ||
320 | s = block_job_create(job_id, &stream_job_driver, NULL, cor_filter_bs, | |
048954e2 | 321 | 0, BLK_PERM_ALL, |
cf6320df | 322 | speed, creation_flags, NULL, NULL, errp); |
a170a91f KW |
323 | if (!s) { |
324 | goto fail; | |
325 | } | |
326 | ||
048954e2 VSO |
327 | s->blk = blk_new_with_bs(cor_filter_bs, BLK_PERM_CONSISTENT_READ, |
328 | basic_flags | BLK_PERM_WRITE, errp); | |
329 | if (!s->blk) { | |
330 | goto fail; | |
331 | } | |
332 | /* | |
333 | * Disable request queuing in the BlockBackend to avoid deadlocks on drain: | |
334 | * The job reports that it's busy until it reaches a pause point. | |
335 | */ | |
336 | blk_set_disable_request_queuing(s->blk, true); | |
337 | blk_set_allow_aio_context_change(s->blk, true); | |
338 | ||
205736f4 AS |
339 | /* |
340 | * Prevent concurrent jobs trying to modify the graph structure here, we | |
341 | * already have our own plans. Also don't allow resize as the image size is | |
342 | * queried only at the job start and then cached. | |
343 | */ | |
344 | if (block_job_add_bdrv(&s->common, "active node", bs, 0, | |
1bf26076 | 345 | basic_flags | BLK_PERM_WRITE, errp)) { |
205736f4 AS |
346 | goto fail; |
347 | } | |
348 | ||
a170a91f KW |
349 | /* Block all intermediate nodes between bs and base, because they will |
350 | * disappear from the chain after this operation. The streaming job reads | |
c624b015 AS |
351 | * every block only once, assuming that it doesn't change, so forbid writes |
352 | * and resizes. Reassign the base node pointer because the backing BS of the | |
353 | * bottom node might change after the call to bdrv_reopen_set_read_only() | |
354 | * due to parallel block jobs running. | |
67acfd21 HR |
355 | * above_base node might change after the call to |
356 | * bdrv_reopen_set_read_only() due to parallel block jobs running. | |
c624b015 | 357 | */ |
67acfd21 HR |
358 | base = bdrv_filter_or_cow_bs(above_base); |
359 | for (iter = bdrv_filter_or_cow_bs(bs); iter != base; | |
360 | iter = bdrv_filter_or_cow_bs(iter)) | |
361 | { | |
1bf26076 KW |
362 | ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0, |
363 | basic_flags, errp); | |
364 | if (ret < 0) { | |
365 | goto fail; | |
366 | } | |
61b49e48 AG |
367 | } |
368 | ||
67acfd21 HR |
369 | s->base_overlay = base_overlay; |
370 | s->above_base = above_base; | |
13d8cc51 | 371 | s->backing_file_str = g_strdup(backing_file_str); |
205736f4 | 372 | s->cor_filter_bs = cor_filter_bs; |
0f6c9498 | 373 | s->target_bs = bs; |
e7d22f8b | 374 | s->bs_read_only = bs_read_only; |
4f1043b4 | 375 | |
1d809098 | 376 | s->on_error = on_error; |
5ccac6f1 | 377 | trace_stream_start(bs, base, s); |
da01ff7f | 378 | job_start(&s->common.job); |
a170a91f KW |
379 | return; |
380 | ||
381 | fail: | |
1bf26076 KW |
382 | if (s) { |
383 | job_early_fail(&s->common.job); | |
384 | } | |
205736f4 AS |
385 | if (cor_filter_bs) { |
386 | bdrv_cor_filter_drop(cor_filter_bs); | |
387 | } | |
e7d22f8b AG |
388 | if (bs_read_only) { |
389 | bdrv_reopen_set_read_only(bs, true, NULL); | |
a170a91f | 390 | } |
4f1043b4 | 391 | } |