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-common.h" 14 #include "block/block_int.h" 15 #include "sysemu/replay.h" 16 #include "qapi/error.h" 17 18 typedef struct Request { 19 Coroutine *co; 20 QEMUBH *bh; 21 } Request; 22 23 static int blkreplay_open(BlockDriverState *bs, QDict *options, int flags, 24 Error **errp) 25 { 26 Error *local_err = NULL; 27 int ret; 28 29 /* Open the image file */ 30 bs->file = bdrv_open_child(NULL, options, "image", 31 bs, &child_file, false, &local_err); 32 if (local_err) { 33 ret = -EINVAL; 34 error_propagate(errp, local_err); 35 goto fail; 36 } 37 38 ret = 0; 39 fail: 40 if (ret < 0) { 41 bdrv_unref_child(bs, bs->file); 42 } 43 return ret; 44 } 45 46 static void blkreplay_close(BlockDriverState *bs) 47 { 48 } 49 50 static int64_t blkreplay_getlength(BlockDriverState *bs) 51 { 52 return bdrv_getlength(bs->file->bs); 53 } 54 55 /* This bh is used for synchronization of return from coroutines. 56 It continues yielded coroutine which then finishes its execution. 57 BH is called adjusted to some replay checkpoint, therefore 58 record and replay will always finish coroutines deterministically. 59 */ 60 static void blkreplay_bh_cb(void *opaque) 61 { 62 Request *req = opaque; 63 aio_co_wake(req->co); 64 qemu_bh_delete(req->bh); 65 g_free(req); 66 } 67 68 static void block_request_create(uint64_t reqid, BlockDriverState *bs, 69 Coroutine *co) 70 { 71 Request *req = g_new(Request, 1); 72 *req = (Request) { 73 .co = co, 74 .bh = aio_bh_new(bdrv_get_aio_context(bs), blkreplay_bh_cb, req), 75 }; 76 replay_block_event(req->bh, reqid); 77 } 78 79 static int coroutine_fn blkreplay_co_preadv(BlockDriverState *bs, 80 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags) 81 { 82 uint64_t reqid = blkreplay_next_id(); 83 int ret = bdrv_co_preadv(bs->file, offset, bytes, qiov, flags); 84 block_request_create(reqid, bs, qemu_coroutine_self()); 85 qemu_coroutine_yield(); 86 87 return ret; 88 } 89 90 static int coroutine_fn blkreplay_co_pwritev(BlockDriverState *bs, 91 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags) 92 { 93 uint64_t reqid = blkreplay_next_id(); 94 int ret = bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags); 95 block_request_create(reqid, bs, qemu_coroutine_self()); 96 qemu_coroutine_yield(); 97 98 return ret; 99 } 100 101 static int coroutine_fn blkreplay_co_pwrite_zeroes(BlockDriverState *bs, 102 int64_t offset, int count, BdrvRequestFlags flags) 103 { 104 uint64_t reqid = blkreplay_next_id(); 105 int ret = bdrv_co_pwrite_zeroes(bs->file, offset, count, flags); 106 block_request_create(reqid, bs, qemu_coroutine_self()); 107 qemu_coroutine_yield(); 108 109 return ret; 110 } 111 112 static int coroutine_fn blkreplay_co_pdiscard(BlockDriverState *bs, 113 int64_t offset, int count) 114 { 115 uint64_t reqid = blkreplay_next_id(); 116 int ret = bdrv_co_pdiscard(bs->file->bs, offset, count); 117 block_request_create(reqid, bs, qemu_coroutine_self()); 118 qemu_coroutine_yield(); 119 120 return ret; 121 } 122 123 static int coroutine_fn blkreplay_co_flush(BlockDriverState *bs) 124 { 125 uint64_t reqid = blkreplay_next_id(); 126 int ret = bdrv_co_flush(bs->file->bs); 127 block_request_create(reqid, bs, qemu_coroutine_self()); 128 qemu_coroutine_yield(); 129 130 return ret; 131 } 132 133 static BlockDriver bdrv_blkreplay = { 134 .format_name = "blkreplay", 135 .protocol_name = "blkreplay", 136 .instance_size = 0, 137 138 .bdrv_file_open = blkreplay_open, 139 .bdrv_close = blkreplay_close, 140 .bdrv_getlength = blkreplay_getlength, 141 142 .bdrv_co_preadv = blkreplay_co_preadv, 143 .bdrv_co_pwritev = blkreplay_co_pwritev, 144 145 .bdrv_co_pwrite_zeroes = blkreplay_co_pwrite_zeroes, 146 .bdrv_co_pdiscard = blkreplay_co_pdiscard, 147 .bdrv_co_flush = blkreplay_co_flush, 148 }; 149 150 static void bdrv_blkreplay_init(void) 151 { 152 bdrv_register(&bdrv_blkreplay); 153 } 154 155 block_init(bdrv_blkreplay_init); 156