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 bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED; 39 bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED; 40 41 ret = 0; 42 fail: 43 return ret; 44 } 45 46 static int64_t blkreplay_getlength(BlockDriverState *bs) 47 { 48 return bdrv_getlength(bs->file->bs); 49 } 50 51 /* This bh is used for synchronization of return from coroutines. 52 It continues yielded coroutine which then finishes its execution. 53 BH is called adjusted to some replay checkpoint, therefore 54 record and replay will always finish coroutines deterministically. 55 */ 56 static void blkreplay_bh_cb(void *opaque) 57 { 58 Request *req = opaque; 59 aio_co_wake(req->co); 60 qemu_bh_delete(req->bh); 61 g_free(req); 62 } 63 64 static void block_request_create(uint64_t reqid, BlockDriverState *bs, 65 Coroutine *co) 66 { 67 Request *req = g_new(Request, 1); 68 *req = (Request) { 69 .co = co, 70 .bh = aio_bh_new(bdrv_get_aio_context(bs), blkreplay_bh_cb, req), 71 }; 72 replay_block_event(req->bh, reqid); 73 } 74 75 static int coroutine_fn blkreplay_co_preadv(BlockDriverState *bs, 76 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags) 77 { 78 uint64_t reqid = blkreplay_next_id(); 79 int ret = bdrv_co_preadv(bs->file, offset, bytes, qiov, flags); 80 block_request_create(reqid, bs, qemu_coroutine_self()); 81 qemu_coroutine_yield(); 82 83 return ret; 84 } 85 86 static int coroutine_fn blkreplay_co_pwritev(BlockDriverState *bs, 87 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int 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 blkreplay_co_pwrite_zeroes(BlockDriverState *bs, 98 int64_t offset, int bytes, BdrvRequestFlags flags) 99 { 100 uint64_t reqid = blkreplay_next_id(); 101 int ret = bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags); 102 block_request_create(reqid, bs, qemu_coroutine_self()); 103 qemu_coroutine_yield(); 104 105 return ret; 106 } 107 108 static int coroutine_fn blkreplay_co_pdiscard(BlockDriverState *bs, 109 int64_t offset, int bytes) 110 { 111 uint64_t reqid = blkreplay_next_id(); 112 int ret = bdrv_co_pdiscard(bs->file, offset, bytes); 113 block_request_create(reqid, bs, qemu_coroutine_self()); 114 qemu_coroutine_yield(); 115 116 return ret; 117 } 118 119 static int coroutine_fn blkreplay_co_flush(BlockDriverState *bs) 120 { 121 uint64_t reqid = blkreplay_next_id(); 122 int ret = bdrv_co_flush(bs->file->bs); 123 block_request_create(reqid, bs, qemu_coroutine_self()); 124 qemu_coroutine_yield(); 125 126 return ret; 127 } 128 129 static BlockDriver bdrv_blkreplay = { 130 .format_name = "blkreplay", 131 .instance_size = 0, 132 133 .bdrv_open = blkreplay_open, 134 .bdrv_child_perm = bdrv_filter_default_perms, 135 .bdrv_getlength = blkreplay_getlength, 136 137 .bdrv_co_preadv = blkreplay_co_preadv, 138 .bdrv_co_pwritev = blkreplay_co_pwritev, 139 140 .bdrv_co_pwrite_zeroes = blkreplay_co_pwrite_zeroes, 141 .bdrv_co_pdiscard = blkreplay_co_pdiscard, 142 .bdrv_co_flush = blkreplay_co_flush, 143 }; 144 145 static void bdrv_blkreplay_init(void) 146 { 147 bdrv_register(&bdrv_blkreplay); 148 } 149 150 block_init(bdrv_blkreplay_init); 151