1 /*
2 * Block protocol for record/replay
3 *
4 * Copyright (c) 2010-2016 Institute for System Programming
5 * of the Russian Academy of Sciences.
6 *
7 * This work is licensed under the terms of the GNU GPL, version 2 or later.
8 * See the COPYING file in the top-level directory.
9 *
10 */
11
12 #include "qemu/osdep.h"
13 #include "qemu/module.h"
14 #include "block/block-io.h"
15 #include "block/block_int.h"
16 #include "sysemu/replay.h"
17 #include "qapi/error.h"
18
19 typedef struct Request {
20 Coroutine *co;
21 QEMUBH *bh;
22 } Request;
23
blkreplay_open(BlockDriverState * bs,QDict * options,int flags,Error ** errp)24 static int blkreplay_open(BlockDriverState *bs, QDict *options, int flags,
25 Error **errp)
26 {
27 int ret;
28
29 /* Open the image file */
30 ret = bdrv_open_file_child(NULL, options, "image", bs, errp);
31 if (ret < 0) {
32 goto fail;
33 }
34
35 bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED;
36 bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED;
37
38 ret = 0;
39 fail:
40 return ret;
41 }
42
43 static int64_t coroutine_fn GRAPH_RDLOCK
blkreplay_co_getlength(BlockDriverState * bs)44 blkreplay_co_getlength(BlockDriverState *bs)
45 {
46 return bdrv_co_getlength(bs->file->bs);
47 }
48
49 /* This bh is used for synchronization of return from coroutines.
50 It continues yielded coroutine which then finishes its execution.
51 BH is called adjusted to some replay checkpoint, therefore
52 record and replay will always finish coroutines deterministically.
53 */
blkreplay_bh_cb(void * opaque)54 static void blkreplay_bh_cb(void *opaque)
55 {
56 Request *req = opaque;
57 aio_co_wake(req->co);
58 qemu_bh_delete(req->bh);
59 g_free(req);
60 }
61
block_request_create(uint64_t reqid,BlockDriverState * bs,Coroutine * co)62 static void block_request_create(uint64_t reqid, BlockDriverState *bs,
63 Coroutine *co)
64 {
65 Request *req = g_new(Request, 1);
66 *req = (Request) {
67 .co = co,
68 .bh = aio_bh_new(bdrv_get_aio_context(bs), blkreplay_bh_cb, req),
69 };
70 replay_block_event(req->bh, reqid);
71 }
72
73 static int coroutine_fn GRAPH_RDLOCK
blkreplay_co_preadv(BlockDriverState * bs,int64_t offset,int64_t bytes,QEMUIOVector * qiov,BdrvRequestFlags flags)74 blkreplay_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
75 QEMUIOVector *qiov, BdrvRequestFlags flags)
76 {
77 uint64_t reqid = blkreplay_next_id();
78 int ret = bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
79 block_request_create(reqid, bs, qemu_coroutine_self());
80 qemu_coroutine_yield();
81
82 return ret;
83 }
84
85 static int coroutine_fn GRAPH_RDLOCK
blkreplay_co_pwritev(BlockDriverState * bs,int64_t offset,int64_t bytes,QEMUIOVector * qiov,BdrvRequestFlags flags)86 blkreplay_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
87 QEMUIOVector *qiov, BdrvRequestFlags flags)
88 {
89 uint64_t reqid = blkreplay_next_id();
90 int ret = bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags);
91 block_request_create(reqid, bs, qemu_coroutine_self());
92 qemu_coroutine_yield();
93
94 return ret;
95 }
96
97 static int coroutine_fn GRAPH_RDLOCK
blkreplay_co_pwrite_zeroes(BlockDriverState * bs,int64_t offset,int64_t bytes,BdrvRequestFlags flags)98 blkreplay_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int64_t bytes,
99 BdrvRequestFlags flags)
100 {
101 uint64_t reqid = blkreplay_next_id();
102 int ret = bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags);
103 block_request_create(reqid, bs, qemu_coroutine_self());
104 qemu_coroutine_yield();
105
106 return ret;
107 }
108
109 static int coroutine_fn GRAPH_RDLOCK
blkreplay_co_pdiscard(BlockDriverState * bs,int64_t offset,int64_t bytes)110 blkreplay_co_pdiscard(BlockDriverState *bs, int64_t offset, int64_t bytes)
111 {
112 uint64_t reqid = blkreplay_next_id();
113 int ret = bdrv_co_pdiscard(bs->file, offset, bytes);
114 block_request_create(reqid, bs, qemu_coroutine_self());
115 qemu_coroutine_yield();
116
117 return ret;
118 }
119
blkreplay_co_flush(BlockDriverState * bs)120 static int coroutine_fn GRAPH_RDLOCK blkreplay_co_flush(BlockDriverState *bs)
121 {
122 uint64_t reqid = blkreplay_next_id();
123 int ret = bdrv_co_flush(bs->file->bs);
124 block_request_create(reqid, bs, qemu_coroutine_self());
125 qemu_coroutine_yield();
126
127 return ret;
128 }
129
blkreplay_snapshot_goto(BlockDriverState * bs,const char * snapshot_id)130 static int blkreplay_snapshot_goto(BlockDriverState *bs,
131 const char *snapshot_id)
132 {
133 BlockDriverState *file_bs;
134
135 bdrv_graph_rdlock_main_loop();
136 file_bs = bs->file->bs;
137 bdrv_graph_rdunlock_main_loop();
138
139 return bdrv_snapshot_goto(file_bs, snapshot_id, NULL);
140 }
141
142 static BlockDriver bdrv_blkreplay = {
143 .format_name = "blkreplay",
144 .instance_size = 0,
145 .is_filter = true,
146
147 .bdrv_open = blkreplay_open,
148 .bdrv_child_perm = bdrv_default_perms,
149 .bdrv_co_getlength = blkreplay_co_getlength,
150
151 .bdrv_co_preadv = blkreplay_co_preadv,
152 .bdrv_co_pwritev = blkreplay_co_pwritev,
153
154 .bdrv_co_pwrite_zeroes = blkreplay_co_pwrite_zeroes,
155 .bdrv_co_pdiscard = blkreplay_co_pdiscard,
156 .bdrv_co_flush = blkreplay_co_flush,
157
158 .bdrv_snapshot_goto = blkreplay_snapshot_goto,
159 };
160
bdrv_blkreplay_init(void)161 static void bdrv_blkreplay_init(void)
162 {
163 bdrv_register(&bdrv_blkreplay);
164 }
165
166 block_init(bdrv_blkreplay_init);
167