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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" |
cc7a8ea7 | 19 | #include "qapi/qmp/qerror.h" |
6ef228fc | 20 | #include "qemu/ratelimit.h" |
373340b2 | 21 | #include "sysemu/block-backend.h" |
4f1043b4 SH |
22 | |
23 | enum { | |
24 | /* | |
99136607 VSO |
25 | * Maximum chunk size to feed to copy-on-read. This should be |
26 | * large enough to process multiple clusters in a single call, so | |
27 | * that populating contiguous regions of the image is efficient. | |
4f1043b4 | 28 | */ |
99136607 | 29 | STREAM_CHUNK = 512 * 1024, /* in bytes */ |
4f1043b4 SH |
30 | }; |
31 | ||
32 | typedef struct StreamBlockJob { | |
33 | BlockJob common; | |
67acfd21 HR |
34 | BlockDriverState *base_overlay; /* COW overlay (stream from this) */ |
35 | BlockDriverState *above_base; /* Node directly above the base */ | |
1d809098 | 36 | BlockdevOnError on_error; |
13d8cc51 | 37 | char *backing_file_str; |
e7d22f8b | 38 | bool bs_read_only; |
65854933 | 39 | bool chain_frozen; |
4f1043b4 SH |
40 | } StreamBlockJob; |
41 | ||
03e35d82 | 42 | static int coroutine_fn stream_populate(BlockBackend *blk, |
99136607 | 43 | int64_t offset, uint64_t bytes) |
4f1043b4 | 44 | { |
8493211c | 45 | assert(bytes < SIZE_MAX); |
4f1043b4 | 46 | |
99136607 VSO |
47 | return blk_co_preadv(blk, offset, bytes, NULL, |
48 | BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH); | |
4f1043b4 SH |
49 | } |
50 | ||
65854933 AG |
51 | static void stream_abort(Job *job) |
52 | { | |
53 | StreamBlockJob *s = container_of(job, StreamBlockJob, common.job); | |
54 | ||
55 | if (s->chain_frozen) { | |
56 | BlockJob *bjob = &s->common; | |
67acfd21 | 57 | bdrv_unfreeze_backing_chain(blk_bs(bjob->blk), s->above_base); |
65854933 AG |
58 | } |
59 | } | |
60 | ||
1b57488a | 61 | static int stream_prepare(Job *job) |
f3e69beb | 62 | { |
1908a559 KW |
63 | StreamBlockJob *s = container_of(job, StreamBlockJob, common.job); |
64 | BlockJob *bjob = &s->common; | |
1908a559 | 65 | BlockDriverState *bs = blk_bs(bjob->blk); |
67acfd21 HR |
66 | BlockDriverState *unfiltered_bs = bdrv_skip_filters(bs); |
67 | BlockDriverState *base = bdrv_filter_or_cow_bs(s->above_base); | |
000e5a1c | 68 | BlockDriverState *unfiltered_base = bdrv_skip_filters(base); |
12fa4af6 | 69 | Error *local_err = NULL; |
1b57488a | 70 | int ret = 0; |
f3e69beb | 71 | |
67acfd21 | 72 | bdrv_unfreeze_backing_chain(bs, s->above_base); |
65854933 AG |
73 | s->chain_frozen = false; |
74 | ||
67acfd21 | 75 | if (bdrv_cow_child(unfiltered_bs)) { |
f3e69beb | 76 | const char *base_id = NULL, *base_fmt = NULL; |
000e5a1c AS |
77 | if (unfiltered_base) { |
78 | base_id = s->backing_file_str ?: unfiltered_base->filename; | |
79 | if (unfiltered_base->drv) { | |
80 | base_fmt = unfiltered_base->drv->format_name; | |
f3e69beb SH |
81 | } |
82 | } | |
67acfd21 HR |
83 | bdrv_set_backing_hd(unfiltered_bs, base, &local_err); |
84 | ret = bdrv_change_backing_file(unfiltered_bs, base_id, base_fmt, false); | |
12fa4af6 KW |
85 | if (local_err) { |
86 | error_report_err(local_err); | |
1b57488a | 87 | return -EPERM; |
12fa4af6 | 88 | } |
f3e69beb SH |
89 | } |
90 | ||
1b57488a JS |
91 | return ret; |
92 | } | |
93 | ||
94 | static void stream_clean(Job *job) | |
95 | { | |
96 | StreamBlockJob *s = container_of(job, StreamBlockJob, common.job); | |
97 | BlockJob *bjob = &s->common; | |
98 | BlockDriverState *bs = blk_bs(bjob->blk); | |
99 | ||
61b49e48 | 100 | /* Reopen the image back in read-only mode if necessary */ |
e7d22f8b | 101 | if (s->bs_read_only) { |
a170a91f | 102 | /* Give up write permissions before making it read-only */ |
1908a559 | 103 | blk_set_perm(bjob->blk, 0, BLK_PERM_ALL, &error_abort); |
e7d22f8b | 104 | bdrv_reopen_set_read_only(bs, true, NULL); |
61b49e48 AG |
105 | } |
106 | ||
f3e69beb | 107 | g_free(s->backing_file_str); |
f3e69beb SH |
108 | } |
109 | ||
f67432a2 | 110 | static int coroutine_fn stream_run(Job *job, Error **errp) |
4f1043b4 | 111 | { |
f67432a2 | 112 | StreamBlockJob *s = container_of(job, StreamBlockJob, common.job); |
03e35d82 KW |
113 | BlockBackend *blk = s->common.blk; |
114 | BlockDriverState *bs = blk_bs(blk); | |
67acfd21 HR |
115 | BlockDriverState *unfiltered_bs = bdrv_skip_filters(bs); |
116 | bool enable_cor = !bdrv_cow_child(s->base_overlay); | |
05df8a6a | 117 | int64_t len; |
d535435f | 118 | int64_t offset = 0; |
f14a39cc | 119 | uint64_t delay_ns = 0; |
1d809098 | 120 | int error = 0; |
51b0a488 | 121 | int64_t n = 0; /* bytes */ |
4f1043b4 | 122 | |
67acfd21 | 123 | if (unfiltered_bs == s->base_overlay) { |
c624b015 | 124 | /* Nothing to stream */ |
96a07d5b | 125 | return 0; |
f4a193e7 HR |
126 | } |
127 | ||
05df8a6a KW |
128 | len = bdrv_getlength(bs); |
129 | if (len < 0) { | |
96a07d5b | 130 | return len; |
4f1043b4 | 131 | } |
30a5c887 | 132 | job_progress_set_remaining(&s->common.job, len); |
4f1043b4 | 133 | |
4f1043b4 SH |
134 | /* Turn on copy-on-read for the whole block device so that guest read |
135 | * requests help us make progress. Only do this when copying the entire | |
136 | * backing chain since the copy-on-read operation does not take base into | |
137 | * account. | |
138 | */ | |
c624b015 | 139 | if (enable_cor) { |
4f1043b4 SH |
140 | bdrv_enable_copy_on_read(bs); |
141 | } | |
142 | ||
05df8a6a | 143 | for ( ; offset < len; offset += n) { |
f9749f28 | 144 | bool copy; |
35c94535 | 145 | int ret; |
4513eafe | 146 | |
4513eafe | 147 | /* Note that even when no rate limit is applied we need to yield |
c57b6656 | 148 | * with no pending I/O here so that bdrv_drain_all() returns. |
4513eafe | 149 | */ |
5d43e86e | 150 | job_sleep_ns(&s->common.job, delay_ns); |
daa7f2f9 | 151 | if (job_is_cancelled(&s->common.job)) { |
4f1043b4 SH |
152 | break; |
153 | } | |
154 | ||
c3e4f43a SW |
155 | copy = false; |
156 | ||
67acfd21 | 157 | ret = bdrv_is_allocated(unfiltered_bs, offset, STREAM_CHUNK, &n); |
f9749f28 PB |
158 | if (ret == 1) { |
159 | /* Allocated in the top, no need to copy. */ | |
d663640c | 160 | } else if (ret >= 0) { |
f9749f28 | 161 | /* Copy if allocated in the intermediate images. Limit to the |
d535435f | 162 | * known-unallocated area [offset, offset+n*BDRV_SECTOR_SIZE). */ |
67acfd21 HR |
163 | ret = bdrv_is_allocated_above(bdrv_cow_bs(unfiltered_bs), |
164 | s->base_overlay, true, | |
51b0a488 | 165 | offset, n, &n); |
571cd9dc SH |
166 | /* Finish early if end of backing file has been reached */ |
167 | if (ret == 0 && n == 0) { | |
05df8a6a | 168 | n = len - offset; |
571cd9dc SH |
169 | } |
170 | ||
a92b1b06 | 171 | copy = (ret > 0); |
f9749f28 | 172 | } |
51b0a488 | 173 | trace_stream_one_iteration(s, offset, n, ret); |
c3e4f43a | 174 | if (copy) { |
99136607 | 175 | ret = stream_populate(blk, offset, n); |
4f1043b4 SH |
176 | } |
177 | if (ret < 0) { | |
1d809098 | 178 | BlockErrorAction action = |
81e254dc | 179 | block_job_error_action(&s->common, s->on_error, true, -ret); |
a589569f | 180 | if (action == BLOCK_ERROR_ACTION_STOP) { |
1d809098 PB |
181 | n = 0; |
182 | continue; | |
183 | } | |
184 | if (error == 0) { | |
185 | error = ret; | |
186 | } | |
a589569f | 187 | if (action == BLOCK_ERROR_ACTION_REPORT) { |
1d809098 PB |
188 | break; |
189 | } | |
4f1043b4 SH |
190 | } |
191 | ||
192 | /* Publish progress */ | |
30a5c887 | 193 | job_progress_update(&s->common.job, n); |
dee81d51 KW |
194 | if (copy) { |
195 | delay_ns = block_job_ratelimit_get_delay(&s->common, n); | |
2fe4bba1 KW |
196 | } else { |
197 | delay_ns = 0; | |
f14a39cc | 198 | } |
4f1043b4 SH |
199 | } |
200 | ||
c624b015 | 201 | if (enable_cor) { |
4f1043b4 SH |
202 | bdrv_disable_copy_on_read(bs); |
203 | } | |
204 | ||
96a07d5b AS |
205 | /* Do not remove the backing file if an error was there but ignored. */ |
206 | return error; | |
4f1043b4 SH |
207 | } |
208 | ||
3fc4b10a | 209 | static const BlockJobDriver stream_job_driver = { |
33e9e9bd KW |
210 | .job_driver = { |
211 | .instance_size = sizeof(StreamBlockJob), | |
252291ea | 212 | .job_type = JOB_TYPE_STREAM, |
80fa2c75 | 213 | .free = block_job_free, |
f67432a2 | 214 | .run = stream_run, |
1b57488a | 215 | .prepare = stream_prepare, |
65854933 | 216 | .abort = stream_abort, |
1b57488a | 217 | .clean = stream_clean, |
b15de828 | 218 | .user_resume = block_job_user_resume, |
33e9e9bd | 219 | }, |
4f1043b4 SH |
220 | }; |
221 | ||
2323322e AG |
222 | void stream_start(const char *job_id, BlockDriverState *bs, |
223 | BlockDriverState *base, const char *backing_file_str, | |
7f4a396d | 224 | BlockDriverState *bottom, |
cf6320df | 225 | int creation_flags, int64_t speed, |
880747a8 AS |
226 | BlockdevOnError on_error, |
227 | const char *filter_node_name, | |
228 | Error **errp) | |
4f1043b4 SH |
229 | { |
230 | StreamBlockJob *s; | |
61b49e48 | 231 | BlockDriverState *iter; |
e7d22f8b | 232 | bool bs_read_only; |
c624b015 | 233 | int basic_flags = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED; |
7f4a396d | 234 | BlockDriverState *base_overlay; |
67acfd21 | 235 | BlockDriverState *above_base; |
4f1043b4 | 236 | |
7f4a396d VSO |
237 | assert(!(base && bottom)); |
238 | assert(!(backing_file_str && bottom)); | |
239 | ||
240 | if (bottom) { | |
241 | /* | |
242 | * New simple interface. The code is written in terms of old interface | |
243 | * with @base parameter (still, it doesn't freeze link to base, so in | |
244 | * this mean old code is correct for new interface). So, for now, just | |
245 | * emulate base_overlay and above_base. Still, when old interface | |
246 | * finally removed, we should refactor code to use only "bottom", but | |
247 | * not "*base*" things. | |
248 | */ | |
249 | assert(!bottom->drv->is_filter); | |
250 | base_overlay = above_base = bottom; | |
251 | } else { | |
252 | base_overlay = bdrv_find_overlay(bs, base); | |
253 | if (!base_overlay) { | |
254 | error_setg(errp, "'%s' is not in the backing chain of '%s'", | |
255 | base->node_name, bs->node_name); | |
256 | return; | |
257 | } | |
67acfd21 | 258 | |
7f4a396d VSO |
259 | /* |
260 | * Find the node directly above @base. @base_overlay is a COW overlay, | |
261 | * so it must have a bdrv_cow_child(), but it is the immediate overlay | |
262 | * of @base, so between the two there can only be filters. | |
263 | */ | |
264 | above_base = base_overlay; | |
265 | if (bdrv_cow_bs(above_base) != base) { | |
266 | above_base = bdrv_cow_bs(above_base); | |
267 | while (bdrv_filter_bs(above_base) != base) { | |
268 | above_base = bdrv_filter_bs(above_base); | |
269 | } | |
67acfd21 HR |
270 | } |
271 | } | |
272 | ||
273 | if (bdrv_freeze_backing_chain(bs, above_base, errp) < 0) { | |
20509c4b AG |
274 | return; |
275 | } | |
276 | ||
61b49e48 | 277 | /* Make sure that the image is opened in read-write mode */ |
e7d22f8b AG |
278 | bs_read_only = bdrv_is_read_only(bs); |
279 | if (bs_read_only) { | |
280 | if (bdrv_reopen_set_read_only(bs, false, errp) != 0) { | |
20509c4b AG |
281 | bs_read_only = false; |
282 | goto fail; | |
61b49e48 AG |
283 | } |
284 | } | |
285 | ||
a170a91f KW |
286 | /* Prevent concurrent jobs trying to modify the graph structure here, we |
287 | * already have our own plans. Also don't allow resize as the image size is | |
288 | * queried only at the job start and then cached. */ | |
75859b94 | 289 | s = block_job_create(job_id, &stream_job_driver, NULL, bs, |
c624b015 AS |
290 | basic_flags | BLK_PERM_GRAPH_MOD, |
291 | basic_flags | BLK_PERM_WRITE, | |
cf6320df | 292 | speed, creation_flags, NULL, NULL, errp); |
a170a91f KW |
293 | if (!s) { |
294 | goto fail; | |
295 | } | |
296 | ||
297 | /* Block all intermediate nodes between bs and base, because they will | |
298 | * disappear from the chain after this operation. The streaming job reads | |
c624b015 AS |
299 | * every block only once, assuming that it doesn't change, so forbid writes |
300 | * and resizes. Reassign the base node pointer because the backing BS of the | |
301 | * bottom node might change after the call to bdrv_reopen_set_read_only() | |
302 | * due to parallel block jobs running. | |
67acfd21 HR |
303 | * above_base node might change after the call to |
304 | * bdrv_reopen_set_read_only() due to parallel block jobs running. | |
c624b015 | 305 | */ |
67acfd21 HR |
306 | base = bdrv_filter_or_cow_bs(above_base); |
307 | for (iter = bdrv_filter_or_cow_bs(bs); iter != base; | |
308 | iter = bdrv_filter_or_cow_bs(iter)) | |
309 | { | |
76d554e2 | 310 | block_job_add_bdrv(&s->common, "intermediate node", iter, 0, |
c624b015 | 311 | basic_flags, &error_abort); |
61b49e48 AG |
312 | } |
313 | ||
67acfd21 HR |
314 | s->base_overlay = base_overlay; |
315 | s->above_base = above_base; | |
13d8cc51 | 316 | s->backing_file_str = g_strdup(backing_file_str); |
e7d22f8b | 317 | s->bs_read_only = bs_read_only; |
65854933 | 318 | s->chain_frozen = true; |
4f1043b4 | 319 | |
1d809098 | 320 | s->on_error = on_error; |
5ccac6f1 | 321 | trace_stream_start(bs, base, s); |
da01ff7f | 322 | job_start(&s->common.job); |
a170a91f KW |
323 | return; |
324 | ||
325 | fail: | |
e7d22f8b AG |
326 | if (bs_read_only) { |
327 | bdrv_reopen_set_read_only(bs, true, NULL); | |
a170a91f | 328 | } |
67acfd21 | 329 | bdrv_unfreeze_backing_chain(bs, above_base); |
4f1043b4 | 330 | } |