Vladimir Sementsov-Ogievskiy | 1c14eaa | 2022-03-03 20:43:44 +0100 | [diff] [blame] | 1 | /* |
| 2 | * snapshot_access block driver |
| 3 | * |
| 4 | * Copyright (c) 2022 Virtuozzo International GmbH. |
| 5 | * |
| 6 | * Author: |
| 7 | * Sementsov-Ogievskiy Vladimir <vsementsov@virtuozzo.com> |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify |
| 10 | * it under the terms of the GNU General Public License as published by |
| 11 | * the Free Software Foundation; either version 2 of the License, or |
| 12 | * (at your option) any later version. |
| 13 | * |
| 14 | * This program is distributed in the hope that it will be useful, |
| 15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 17 | * GNU General Public License for more details. |
| 18 | * |
| 19 | * You should have received a copy of the GNU General Public License |
| 20 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 21 | */ |
| 22 | |
| 23 | #include "qemu/osdep.h" |
| 24 | |
| 25 | #include "sysemu/block-backend.h" |
| 26 | #include "qemu/cutils.h" |
| 27 | #include "block/block_int.h" |
| 28 | |
Kevin Wolf | 7b9e8b2 | 2023-02-03 16:21:54 +0100 | [diff] [blame] | 29 | static int coroutine_fn GRAPH_RDLOCK |
Vladimir Sementsov-Ogievskiy | 1c14eaa | 2022-03-03 20:43:44 +0100 | [diff] [blame] | 30 | snapshot_access_co_preadv_part(BlockDriverState *bs, |
| 31 | int64_t offset, int64_t bytes, |
| 32 | QEMUIOVector *qiov, size_t qiov_offset, |
| 33 | BdrvRequestFlags flags) |
| 34 | { |
| 35 | if (flags) { |
| 36 | return -ENOTSUP; |
| 37 | } |
| 38 | |
| 39 | return bdrv_co_preadv_snapshot(bs->file, offset, bytes, qiov, qiov_offset); |
| 40 | } |
| 41 | |
Kevin Wolf | 7b9e8b2 | 2023-02-03 16:21:54 +0100 | [diff] [blame] | 42 | static int coroutine_fn GRAPH_RDLOCK |
Vladimir Sementsov-Ogievskiy | 1c14eaa | 2022-03-03 20:43:44 +0100 | [diff] [blame] | 43 | snapshot_access_co_block_status(BlockDriverState *bs, |
| 44 | bool want_zero, int64_t offset, |
| 45 | int64_t bytes, int64_t *pnum, |
| 46 | int64_t *map, BlockDriverState **file) |
| 47 | { |
| 48 | return bdrv_co_snapshot_block_status(bs->file->bs, want_zero, offset, |
| 49 | bytes, pnum, map, file); |
| 50 | } |
| 51 | |
Emanuele Giuseppe Esposito | 9a5a1c6 | 2023-02-03 16:21:47 +0100 | [diff] [blame] | 52 | static int coroutine_fn GRAPH_RDLOCK |
| 53 | snapshot_access_co_pdiscard(BlockDriverState *bs, int64_t offset, int64_t bytes) |
Vladimir Sementsov-Ogievskiy | 1c14eaa | 2022-03-03 20:43:44 +0100 | [diff] [blame] | 54 | { |
| 55 | return bdrv_co_pdiscard_snapshot(bs->file->bs, offset, bytes); |
| 56 | } |
| 57 | |
| 58 | static int coroutine_fn |
| 59 | snapshot_access_co_pwrite_zeroes(BlockDriverState *bs, |
| 60 | int64_t offset, int64_t bytes, |
| 61 | BdrvRequestFlags flags) |
| 62 | { |
| 63 | return -ENOTSUP; |
| 64 | } |
| 65 | |
| 66 | static coroutine_fn int |
| 67 | snapshot_access_co_pwritev_part(BlockDriverState *bs, |
| 68 | int64_t offset, int64_t bytes, |
| 69 | QEMUIOVector *qiov, size_t qiov_offset, |
| 70 | BdrvRequestFlags flags) |
| 71 | { |
| 72 | return -ENOTSUP; |
| 73 | } |
| 74 | |
| 75 | |
| 76 | static void snapshot_access_refresh_filename(BlockDriverState *bs) |
| 77 | { |
| 78 | pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), |
| 79 | bs->file->bs->filename); |
| 80 | } |
| 81 | |
| 82 | static int snapshot_access_open(BlockDriverState *bs, QDict *options, int flags, |
| 83 | Error **errp) |
| 84 | { |
Vladimir Sementsov-Ogievskiy | 5bb04747 | 2022-07-26 23:11:32 +0300 | [diff] [blame] | 85 | bdrv_open_child(NULL, options, "file", bs, &child_of_bds, |
| 86 | BDRV_CHILD_DATA | BDRV_CHILD_PRIMARY, |
| 87 | false, errp); |
Vladimir Sementsov-Ogievskiy | 1c14eaa | 2022-03-03 20:43:44 +0100 | [diff] [blame] | 88 | if (!bs->file) { |
| 89 | return -EINVAL; |
| 90 | } |
| 91 | |
| 92 | bs->total_sectors = bs->file->bs->total_sectors; |
| 93 | |
| 94 | return 0; |
| 95 | } |
| 96 | |
| 97 | static void snapshot_access_child_perm(BlockDriverState *bs, BdrvChild *c, |
| 98 | BdrvChildRole role, |
| 99 | BlockReopenQueue *reopen_queue, |
| 100 | uint64_t perm, uint64_t shared, |
| 101 | uint64_t *nperm, uint64_t *nshared) |
| 102 | { |
| 103 | /* |
| 104 | * Currently, we don't need any permissions. If bs->file provides |
| 105 | * snapshot-access API, we can use it. |
| 106 | */ |
| 107 | *nperm = 0; |
| 108 | *nshared = BLK_PERM_ALL; |
| 109 | } |
| 110 | |
| 111 | BlockDriver bdrv_snapshot_access_drv = { |
| 112 | .format_name = "snapshot-access", |
| 113 | |
| 114 | .bdrv_open = snapshot_access_open, |
| 115 | |
| 116 | .bdrv_co_preadv_part = snapshot_access_co_preadv_part, |
| 117 | .bdrv_co_pwritev_part = snapshot_access_co_pwritev_part, |
| 118 | .bdrv_co_pwrite_zeroes = snapshot_access_co_pwrite_zeroes, |
| 119 | .bdrv_co_pdiscard = snapshot_access_co_pdiscard, |
| 120 | .bdrv_co_block_status = snapshot_access_co_block_status, |
| 121 | |
| 122 | .bdrv_refresh_filename = snapshot_access_refresh_filename, |
| 123 | |
| 124 | .bdrv_child_perm = snapshot_access_child_perm, |
| 125 | }; |
| 126 | |
| 127 | static void snapshot_access_init(void) |
| 128 | { |
| 129 | bdrv_register(&bdrv_snapshot_access_drv); |
| 130 | } |
| 131 | |
| 132 | block_init(snapshot_access_init); |