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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 PB |
16 | #include "block/block_int.h" |
17 | #include "block/blockjob.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 | /* | |
25 | * Size of data buffer for populating the image file. This should be large | |
26 | * enough to process multiple clusters in a single call, so that populating | |
27 | * contiguous regions of the image is efficient. | |
28 | */ | |
29 | STREAM_BUFFER_SIZE = 512 * 1024, /* in bytes */ | |
30 | }; | |
31 | ||
5094a6c0 SH |
32 | #define SLICE_TIME 100000000ULL /* ns */ |
33 | ||
4f1043b4 SH |
34 | typedef struct StreamBlockJob { |
35 | BlockJob common; | |
5094a6c0 | 36 | RateLimit limit; |
4f1043b4 | 37 | BlockDriverState *base; |
1d809098 | 38 | BlockdevOnError on_error; |
13d8cc51 | 39 | char *backing_file_str; |
4f1043b4 SH |
40 | } StreamBlockJob; |
41 | ||
42 | static int coroutine_fn stream_populate(BlockDriverState *bs, | |
43 | int64_t sector_num, int nb_sectors, | |
44 | void *buf) | |
45 | { | |
46 | struct iovec iov = { | |
47 | .iov_base = buf, | |
48 | .iov_len = nb_sectors * BDRV_SECTOR_SIZE, | |
49 | }; | |
50 | QEMUIOVector qiov; | |
51 | ||
52 | qemu_iovec_init_external(&qiov, &iov, 1); | |
53 | ||
54 | /* Copy-on-read the unallocated clusters */ | |
55 | return bdrv_co_copy_on_readv(bs, sector_num, nb_sectors, &qiov); | |
56 | } | |
57 | ||
f3e69beb SH |
58 | typedef struct { |
59 | int ret; | |
60 | bool reached_end; | |
61 | } StreamCompleteData; | |
62 | ||
63 | static void stream_complete(BlockJob *job, void *opaque) | |
64 | { | |
65 | StreamBlockJob *s = container_of(job, StreamBlockJob, common); | |
66 | StreamCompleteData *data = opaque; | |
67 | BlockDriverState *base = s->base; | |
68 | ||
69 | if (!block_job_is_cancelled(&s->common) && data->reached_end && | |
70 | data->ret == 0) { | |
71 | const char *base_id = NULL, *base_fmt = NULL; | |
72 | if (base) { | |
73 | base_id = s->backing_file_str; | |
74 | if (base->drv) { | |
75 | base_fmt = base->drv->format_name; | |
76 | } | |
77 | } | |
78 | data->ret = bdrv_change_backing_file(job->bs, base_id, base_fmt); | |
5db15a57 | 79 | bdrv_set_backing_hd(job->bs, base); |
f3e69beb SH |
80 | } |
81 | ||
82 | g_free(s->backing_file_str); | |
83 | block_job_completed(&s->common, data->ret); | |
84 | g_free(data); | |
85 | } | |
86 | ||
4f1043b4 SH |
87 | static void coroutine_fn stream_run(void *opaque) |
88 | { | |
89 | StreamBlockJob *s = opaque; | |
f3e69beb | 90 | StreamCompleteData *data; |
4f1043b4 | 91 | BlockDriverState *bs = s->common.bs; |
c8c3080f | 92 | BlockDriverState *base = s->base; |
6578629e AG |
93 | int64_t sector_num = 0; |
94 | int64_t end = -1; | |
1d809098 | 95 | int error = 0; |
4f1043b4 | 96 | int ret = 0; |
04120e3b | 97 | int n = 0; |
4f1043b4 SH |
98 | void *buf; |
99 | ||
760e0063 | 100 | if (!bs->backing) { |
6578629e | 101 | goto out; |
f4a193e7 HR |
102 | } |
103 | ||
4f1043b4 SH |
104 | s->common.len = bdrv_getlength(bs); |
105 | if (s->common.len < 0) { | |
6578629e AG |
106 | ret = s->common.len; |
107 | goto out; | |
4f1043b4 SH |
108 | } |
109 | ||
110 | end = s->common.len >> BDRV_SECTOR_BITS; | |
111 | buf = qemu_blockalign(bs, STREAM_BUFFER_SIZE); | |
112 | ||
113 | /* Turn on copy-on-read for the whole block device so that guest read | |
114 | * requests help us make progress. Only do this when copying the entire | |
115 | * backing chain since the copy-on-read operation does not take base into | |
116 | * account. | |
117 | */ | |
118 | if (!base) { | |
119 | bdrv_enable_copy_on_read(bs); | |
120 | } | |
121 | ||
122 | for (sector_num = 0; sector_num < end; sector_num += n) { | |
4513eafe | 123 | uint64_t delay_ns = 0; |
f9749f28 | 124 | bool copy; |
4513eafe PB |
125 | |
126 | wait: | |
127 | /* Note that even when no rate limit is applied we need to yield | |
c57b6656 | 128 | * with no pending I/O here so that bdrv_drain_all() returns. |
4513eafe | 129 | */ |
7483d1e5 | 130 | block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); |
4f1043b4 SH |
131 | if (block_job_is_cancelled(&s->common)) { |
132 | break; | |
133 | } | |
134 | ||
c3e4f43a SW |
135 | copy = false; |
136 | ||
bdad13b9 PB |
137 | ret = bdrv_is_allocated(bs, sector_num, |
138 | STREAM_BUFFER_SIZE / BDRV_SECTOR_SIZE, &n); | |
f9749f28 PB |
139 | if (ret == 1) { |
140 | /* Allocated in the top, no need to copy. */ | |
d663640c | 141 | } else if (ret >= 0) { |
f9749f28 PB |
142 | /* Copy if allocated in the intermediate images. Limit to the |
143 | * known-unallocated area [sector_num, sector_num+n). */ | |
760e0063 | 144 | ret = bdrv_is_allocated_above(backing_bs(bs), base, |
4f578637 | 145 | sector_num, n, &n); |
571cd9dc SH |
146 | |
147 | /* Finish early if end of backing file has been reached */ | |
148 | if (ret == 0 && n == 0) { | |
149 | n = end - sector_num; | |
150 | } | |
151 | ||
f9749f28 PB |
152 | copy = (ret == 1); |
153 | } | |
4f1043b4 | 154 | trace_stream_one_iteration(s, sector_num, n, ret); |
c3e4f43a | 155 | if (copy) { |
5094a6c0 | 156 | if (s->common.speed) { |
4513eafe | 157 | delay_ns = ratelimit_calculate_delay(&s->limit, n); |
5094a6c0 | 158 | if (delay_ns > 0) { |
4513eafe | 159 | goto wait; |
5094a6c0 SH |
160 | } |
161 | } | |
4f1043b4 SH |
162 | ret = stream_populate(bs, sector_num, n, buf); |
163 | } | |
164 | if (ret < 0) { | |
1d809098 PB |
165 | BlockErrorAction action = |
166 | block_job_error_action(&s->common, s->common.bs, s->on_error, | |
167 | true, -ret); | |
a589569f | 168 | if (action == BLOCK_ERROR_ACTION_STOP) { |
1d809098 PB |
169 | n = 0; |
170 | continue; | |
171 | } | |
172 | if (error == 0) { | |
173 | error = ret; | |
174 | } | |
a589569f | 175 | if (action == BLOCK_ERROR_ACTION_REPORT) { |
1d809098 PB |
176 | break; |
177 | } | |
4f1043b4 | 178 | } |
c8c3080f | 179 | ret = 0; |
4f1043b4 SH |
180 | |
181 | /* Publish progress */ | |
182 | s->common.offset += n * BDRV_SECTOR_SIZE; | |
183 | } | |
184 | ||
185 | if (!base) { | |
186 | bdrv_disable_copy_on_read(bs); | |
187 | } | |
188 | ||
1d809098 PB |
189 | /* Do not remove the backing file if an error was there but ignored. */ |
190 | ret = error; | |
191 | ||
4f1043b4 | 192 | qemu_vfree(buf); |
f3e69beb | 193 | |
6578629e | 194 | out: |
f3e69beb SH |
195 | /* Modify backing chain and close BDSes in main loop */ |
196 | data = g_malloc(sizeof(*data)); | |
197 | data->ret = ret; | |
198 | data->reached_end = sector_num == end; | |
199 | block_job_defer_to_main_loop(&s->common, stream_complete, data); | |
4f1043b4 SH |
200 | } |
201 | ||
882ec7ce | 202 | static void stream_set_speed(BlockJob *job, int64_t speed, Error **errp) |
5094a6c0 SH |
203 | { |
204 | StreamBlockJob *s = container_of(job, StreamBlockJob, common); | |
205 | ||
882ec7ce | 206 | if (speed < 0) { |
c6bd8c70 | 207 | error_setg(errp, QERR_INVALID_PARAMETER, "speed"); |
9e6636c7 | 208 | return; |
5094a6c0 | 209 | } |
6ef228fc | 210 | ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME); |
5094a6c0 SH |
211 | } |
212 | ||
3fc4b10a | 213 | static const BlockJobDriver stream_job_driver = { |
4f1043b4 | 214 | .instance_size = sizeof(StreamBlockJob), |
79e14bf7 | 215 | .job_type = BLOCK_JOB_TYPE_STREAM, |
5094a6c0 | 216 | .set_speed = stream_set_speed, |
4f1043b4 SH |
217 | }; |
218 | ||
fd7f8c65 | 219 | void stream_start(BlockDriverState *bs, BlockDriverState *base, |
13d8cc51 | 220 | const char *backing_file_str, int64_t speed, |
1d809098 | 221 | BlockdevOnError on_error, |
097310b5 | 222 | BlockCompletionFunc *cb, |
fd7f8c65 | 223 | void *opaque, Error **errp) |
4f1043b4 SH |
224 | { |
225 | StreamBlockJob *s; | |
4f1043b4 | 226 | |
1d809098 PB |
227 | if ((on_error == BLOCKDEV_ON_ERROR_STOP || |
228 | on_error == BLOCKDEV_ON_ERROR_ENOSPC) && | |
373340b2 | 229 | (!bs->blk || !blk_iostatus_is_enabled(bs->blk))) { |
c6bd8c70 | 230 | error_setg(errp, QERR_INVALID_PARAMETER, "on-error"); |
1d809098 PB |
231 | return; |
232 | } | |
233 | ||
3fc4b10a | 234 | s = block_job_create(&stream_job_driver, bs, speed, cb, opaque, errp); |
4f1043b4 | 235 | if (!s) { |
fd7f8c65 | 236 | return; |
4f1043b4 SH |
237 | } |
238 | ||
239 | s->base = base; | |
13d8cc51 | 240 | s->backing_file_str = g_strdup(backing_file_str); |
4f1043b4 | 241 | |
1d809098 | 242 | s->on_error = on_error; |
fa4478d5 PB |
243 | s->common.co = qemu_coroutine_create(stream_run); |
244 | trace_stream_start(bs, base, s, s->common.co, opaque); | |
245 | qemu_coroutine_enter(s->common.co, s); | |
4f1043b4 | 246 | } |