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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 | ||
14 | #include "trace.h" | |
15 | #include "block_int.h" | |
2f0c9fe6 | 16 | #include "blockjob.h" |
6ef228fc | 17 | #include "qemu/ratelimit.h" |
4f1043b4 SH |
18 | |
19 | enum { | |
20 | /* | |
21 | * Size of data buffer for populating the image file. This should be large | |
22 | * enough to process multiple clusters in a single call, so that populating | |
23 | * contiguous regions of the image is efficient. | |
24 | */ | |
25 | STREAM_BUFFER_SIZE = 512 * 1024, /* in bytes */ | |
26 | }; | |
27 | ||
5094a6c0 SH |
28 | #define SLICE_TIME 100000000ULL /* ns */ |
29 | ||
4f1043b4 SH |
30 | typedef struct StreamBlockJob { |
31 | BlockJob common; | |
5094a6c0 | 32 | RateLimit limit; |
4f1043b4 | 33 | BlockDriverState *base; |
c8c3080f | 34 | char backing_file_id[1024]; |
4f1043b4 SH |
35 | } StreamBlockJob; |
36 | ||
37 | static int coroutine_fn stream_populate(BlockDriverState *bs, | |
38 | int64_t sector_num, int nb_sectors, | |
39 | void *buf) | |
40 | { | |
41 | struct iovec iov = { | |
42 | .iov_base = buf, | |
43 | .iov_len = nb_sectors * BDRV_SECTOR_SIZE, | |
44 | }; | |
45 | QEMUIOVector qiov; | |
46 | ||
47 | qemu_iovec_init_external(&qiov, &iov, 1); | |
48 | ||
49 | /* Copy-on-read the unallocated clusters */ | |
50 | return bdrv_co_copy_on_readv(bs, sector_num, nb_sectors, &qiov); | |
51 | } | |
52 | ||
5a67a104 MT |
53 | static void close_unused_images(BlockDriverState *top, BlockDriverState *base, |
54 | const char *base_id) | |
55 | { | |
56 | BlockDriverState *intermediate; | |
57 | intermediate = top->backing_hd; | |
58 | ||
59 | while (intermediate) { | |
60 | BlockDriverState *unused; | |
61 | ||
62 | /* reached base */ | |
63 | if (intermediate == base) { | |
64 | break; | |
65 | } | |
66 | ||
67 | unused = intermediate; | |
68 | intermediate = intermediate->backing_hd; | |
69 | unused->backing_hd = NULL; | |
70 | bdrv_delete(unused); | |
71 | } | |
72 | top->backing_hd = base; | |
5a67a104 MT |
73 | } |
74 | ||
4f1043b4 SH |
75 | static void coroutine_fn stream_run(void *opaque) |
76 | { | |
77 | StreamBlockJob *s = opaque; | |
78 | BlockDriverState *bs = s->common.bs; | |
c8c3080f | 79 | BlockDriverState *base = s->base; |
4f1043b4 SH |
80 | int64_t sector_num, end; |
81 | int ret = 0; | |
04120e3b | 82 | int n = 0; |
4f1043b4 SH |
83 | void *buf; |
84 | ||
85 | s->common.len = bdrv_getlength(bs); | |
86 | if (s->common.len < 0) { | |
87 | block_job_complete(&s->common, s->common.len); | |
88 | return; | |
89 | } | |
90 | ||
91 | end = s->common.len >> BDRV_SECTOR_BITS; | |
92 | buf = qemu_blockalign(bs, STREAM_BUFFER_SIZE); | |
93 | ||
94 | /* Turn on copy-on-read for the whole block device so that guest read | |
95 | * requests help us make progress. Only do this when copying the entire | |
96 | * backing chain since the copy-on-read operation does not take base into | |
97 | * account. | |
98 | */ | |
99 | if (!base) { | |
100 | bdrv_enable_copy_on_read(bs); | |
101 | } | |
102 | ||
103 | for (sector_num = 0; sector_num < end; sector_num += n) { | |
4513eafe | 104 | uint64_t delay_ns = 0; |
f9749f28 | 105 | bool copy; |
4513eafe PB |
106 | |
107 | wait: | |
108 | /* Note that even when no rate limit is applied we need to yield | |
109 | * with no pending I/O here so that qemu_aio_flush() returns. | |
110 | */ | |
111 | block_job_sleep_ns(&s->common, rt_clock, delay_ns); | |
4f1043b4 SH |
112 | if (block_job_is_cancelled(&s->common)) { |
113 | break; | |
114 | } | |
115 | ||
f9749f28 PB |
116 | ret = bdrv_co_is_allocated(bs, sector_num, |
117 | STREAM_BUFFER_SIZE / BDRV_SECTOR_SIZE, &n); | |
118 | if (ret == 1) { | |
119 | /* Allocated in the top, no need to copy. */ | |
120 | copy = false; | |
121 | } else { | |
122 | /* Copy if allocated in the intermediate images. Limit to the | |
123 | * known-unallocated area [sector_num, sector_num+n). */ | |
188a7bbf PB |
124 | ret = bdrv_co_is_allocated_above(bs->backing_hd, base, |
125 | sector_num, n, &n); | |
571cd9dc SH |
126 | |
127 | /* Finish early if end of backing file has been reached */ | |
128 | if (ret == 0 && n == 0) { | |
129 | n = end - sector_num; | |
130 | } | |
131 | ||
f9749f28 PB |
132 | copy = (ret == 1); |
133 | } | |
4f1043b4 | 134 | trace_stream_one_iteration(s, sector_num, n, ret); |
f9749f28 | 135 | if (ret >= 0 && copy) { |
5094a6c0 | 136 | if (s->common.speed) { |
4513eafe | 137 | delay_ns = ratelimit_calculate_delay(&s->limit, n); |
5094a6c0 | 138 | if (delay_ns > 0) { |
4513eafe | 139 | goto wait; |
5094a6c0 SH |
140 | } |
141 | } | |
4f1043b4 SH |
142 | ret = stream_populate(bs, sector_num, n, buf); |
143 | } | |
144 | if (ret < 0) { | |
145 | break; | |
146 | } | |
c8c3080f | 147 | ret = 0; |
4f1043b4 SH |
148 | |
149 | /* Publish progress */ | |
150 | s->common.offset += n * BDRV_SECTOR_SIZE; | |
151 | } | |
152 | ||
153 | if (!base) { | |
154 | bdrv_disable_copy_on_read(bs); | |
155 | } | |
156 | ||
3e914655 | 157 | if (!block_job_is_cancelled(&s->common) && sector_num == end && ret == 0) { |
f6133def | 158 | const char *base_id = NULL, *base_fmt = NULL; |
c8c3080f MT |
159 | if (base) { |
160 | base_id = s->backing_file_id; | |
f6133def PB |
161 | if (base->drv) { |
162 | base_fmt = base->drv->format_name; | |
163 | } | |
c8c3080f | 164 | } |
f6133def | 165 | ret = bdrv_change_backing_file(bs, base_id, base_fmt); |
5a67a104 | 166 | close_unused_images(bs, base, base_id); |
4f1043b4 SH |
167 | } |
168 | ||
169 | qemu_vfree(buf); | |
170 | block_job_complete(&s->common, ret); | |
171 | } | |
172 | ||
882ec7ce | 173 | static void stream_set_speed(BlockJob *job, int64_t speed, Error **errp) |
5094a6c0 SH |
174 | { |
175 | StreamBlockJob *s = container_of(job, StreamBlockJob, common); | |
176 | ||
882ec7ce SH |
177 | if (speed < 0) { |
178 | error_set(errp, QERR_INVALID_PARAMETER, "speed"); | |
9e6636c7 | 179 | return; |
5094a6c0 | 180 | } |
6ef228fc | 181 | ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME); |
5094a6c0 SH |
182 | } |
183 | ||
4f1043b4 SH |
184 | static BlockJobType stream_job_type = { |
185 | .instance_size = sizeof(StreamBlockJob), | |
186 | .job_type = "stream", | |
5094a6c0 | 187 | .set_speed = stream_set_speed, |
4f1043b4 SH |
188 | }; |
189 | ||
fd7f8c65 | 190 | void stream_start(BlockDriverState *bs, BlockDriverState *base, |
c83c66c3 SH |
191 | const char *base_id, int64_t speed, |
192 | BlockDriverCompletionFunc *cb, | |
fd7f8c65 | 193 | void *opaque, Error **errp) |
4f1043b4 SH |
194 | { |
195 | StreamBlockJob *s; | |
4f1043b4 | 196 | |
c83c66c3 | 197 | s = block_job_create(&stream_job_type, bs, speed, cb, opaque, errp); |
4f1043b4 | 198 | if (!s) { |
fd7f8c65 | 199 | return; |
4f1043b4 SH |
200 | } |
201 | ||
202 | s->base = base; | |
c8c3080f MT |
203 | if (base_id) { |
204 | pstrcpy(s->backing_file_id, sizeof(s->backing_file_id), base_id); | |
205 | } | |
4f1043b4 | 206 | |
fa4478d5 PB |
207 | s->common.co = qemu_coroutine_create(stream_run); |
208 | trace_stream_start(bs, base, s, s->common.co, opaque); | |
209 | qemu_coroutine_enter(s->common.co, s); | |
4f1043b4 | 210 | } |