1 /* 2 * Compress filter block driver 3 * 4 * Copyright (c) 2019 Virtuozzo International GmbH 5 * 6 * Author: 7 * Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> 8 * (based on block/copy-on-read.c by Max Reitz) 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License as 12 * published by the Free Software Foundation; either version 2 or 13 * (at your option) any later version of the License. 14 * 15 * This program is distributed in the hope that it will be useful, 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 * GNU General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public License 21 * along with this program; if not, see <http://www.gnu.org/licenses/>. 22 */ 23 24 #include "qemu/osdep.h" 25 #include "block/block_int.h" 26 #include "qemu/module.h" 27 #include "qapi/error.h" 28 29 30 static int compress_open(BlockDriverState *bs, QDict *options, int flags, 31 Error **errp) 32 { 33 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, false, 34 errp); 35 if (!bs->file) { 36 return -EINVAL; 37 } 38 39 if (!bs->file->bs->drv || !block_driver_can_compress(bs->file->bs->drv)) { 40 error_setg(errp, 41 "Compression is not supported for underlying format: %s", 42 bdrv_get_format_name(bs->file->bs) ?: "(no format)"); 43 44 return -ENOTSUP; 45 } 46 47 bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED | 48 (BDRV_REQ_FUA & bs->file->bs->supported_write_flags); 49 50 bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED | 51 ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) & 52 bs->file->bs->supported_zero_flags); 53 54 return 0; 55 } 56 57 58 static int64_t compress_getlength(BlockDriverState *bs) 59 { 60 return bdrv_getlength(bs->file->bs); 61 } 62 63 64 static int coroutine_fn compress_co_preadv_part(BlockDriverState *bs, 65 uint64_t offset, uint64_t bytes, 66 QEMUIOVector *qiov, 67 size_t qiov_offset, 68 int flags) 69 { 70 return bdrv_co_preadv_part(bs->file, offset, bytes, qiov, qiov_offset, 71 flags); 72 } 73 74 75 static int coroutine_fn compress_co_pwritev_part(BlockDriverState *bs, 76 uint64_t offset, 77 uint64_t bytes, 78 QEMUIOVector *qiov, 79 size_t qiov_offset, int flags) 80 { 81 return bdrv_co_pwritev_part(bs->file, offset, bytes, qiov, qiov_offset, 82 flags | BDRV_REQ_WRITE_COMPRESSED); 83 } 84 85 86 static int coroutine_fn compress_co_pwrite_zeroes(BlockDriverState *bs, 87 int64_t offset, int bytes, 88 BdrvRequestFlags flags) 89 { 90 return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags); 91 } 92 93 94 static int coroutine_fn compress_co_pdiscard(BlockDriverState *bs, 95 int64_t offset, int bytes) 96 { 97 return bdrv_co_pdiscard(bs->file, offset, bytes); 98 } 99 100 101 static void compress_refresh_limits(BlockDriverState *bs, Error **errp) 102 { 103 BlockDriverInfo bdi; 104 int ret; 105 106 if (!bs->file) { 107 return; 108 } 109 110 ret = bdrv_get_info(bs->file->bs, &bdi); 111 if (ret < 0 || bdi.cluster_size == 0) { 112 return; 113 } 114 115 bs->bl.request_alignment = bdi.cluster_size; 116 } 117 118 119 static void compress_eject(BlockDriverState *bs, bool eject_flag) 120 { 121 bdrv_eject(bs->file->bs, eject_flag); 122 } 123 124 125 static void compress_lock_medium(BlockDriverState *bs, bool locked) 126 { 127 bdrv_lock_medium(bs->file->bs, locked); 128 } 129 130 131 static BlockDriver bdrv_compress = { 132 .format_name = "compress", 133 134 .bdrv_open = compress_open, 135 .bdrv_child_perm = bdrv_filter_default_perms, 136 137 .bdrv_getlength = compress_getlength, 138 139 .bdrv_co_preadv_part = compress_co_preadv_part, 140 .bdrv_co_pwritev_part = compress_co_pwritev_part, 141 .bdrv_co_pwrite_zeroes = compress_co_pwrite_zeroes, 142 .bdrv_co_pdiscard = compress_co_pdiscard, 143 .bdrv_refresh_limits = compress_refresh_limits, 144 145 .bdrv_eject = compress_eject, 146 .bdrv_lock_medium = compress_lock_medium, 147 148 .bdrv_co_block_status = bdrv_co_block_status_from_file, 149 150 .has_variable_length = true, 151 .is_filter = true, 152 }; 153 154 static void bdrv_compress_init(void) 155 { 156 bdrv_register(&bdrv_compress); 157 } 158 159 block_init(bdrv_compress_init); 160