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 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 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 */ 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 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 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 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 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 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 } 119 120 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 } 129 130 static int blkreplay_snapshot_goto(BlockDriverState *bs, 131 const char *snapshot_id) 132 { 133 return bdrv_snapshot_goto(bs->file->bs, snapshot_id, NULL); 134 } 135 136 static BlockDriver bdrv_blkreplay = { 137 .format_name = "blkreplay", 138 .instance_size = 0, 139 .is_filter = true, 140 141 .bdrv_open = blkreplay_open, 142 .bdrv_child_perm = bdrv_default_perms, 143 .bdrv_co_getlength = blkreplay_co_getlength, 144 145 .bdrv_co_preadv = blkreplay_co_preadv, 146 .bdrv_co_pwritev = blkreplay_co_pwritev, 147 148 .bdrv_co_pwrite_zeroes = blkreplay_co_pwrite_zeroes, 149 .bdrv_co_pdiscard = blkreplay_co_pdiscard, 150 .bdrv_co_flush = blkreplay_co_flush, 151 152 .bdrv_snapshot_goto = blkreplay_snapshot_goto, 153 }; 154 155 static void bdrv_blkreplay_init(void) 156 { 157 bdrv_register(&bdrv_blkreplay); 158 } 159 160 block_init(bdrv_blkreplay_init); 161