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_of_bds, 34 BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, 35 false, errp); 36 if (!bs->file) { 37 return -EINVAL; 38 } 39 40 if (!bs->file->bs->drv || !block_driver_can_compress(bs->file->bs->drv)) { 41 error_setg(errp, 42 "Compression is not supported for underlying format: %s", 43 bdrv_get_format_name(bs->file->bs) ?: "(no format)"); 44 45 return -ENOTSUP; 46 } 47 48 bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED | 49 (BDRV_REQ_FUA & bs->file->bs->supported_write_flags); 50 51 bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED | 52 ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) & 53 bs->file->bs->supported_zero_flags); 54 55 return 0; 56 } 57 58 59 static int64_t compress_getlength(BlockDriverState *bs) 60 { 61 return bdrv_getlength(bs->file->bs); 62 } 63 64 65 static int coroutine_fn compress_co_preadv_part(BlockDriverState *bs, 66 uint64_t offset, uint64_t bytes, 67 QEMUIOVector *qiov, 68 size_t qiov_offset, 69 int flags) 70 { 71 return bdrv_co_preadv_part(bs->file, offset, bytes, qiov, qiov_offset, 72 flags); 73 } 74 75 76 static int coroutine_fn compress_co_pwritev_part(BlockDriverState *bs, 77 uint64_t offset, 78 uint64_t bytes, 79 QEMUIOVector *qiov, 80 size_t qiov_offset, int flags) 81 { 82 return bdrv_co_pwritev_part(bs->file, offset, bytes, qiov, qiov_offset, 83 flags | BDRV_REQ_WRITE_COMPRESSED); 84 } 85 86 87 static int coroutine_fn compress_co_pwrite_zeroes(BlockDriverState *bs, 88 int64_t offset, int bytes, 89 BdrvRequestFlags flags) 90 { 91 return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags); 92 } 93 94 95 static int coroutine_fn compress_co_pdiscard(BlockDriverState *bs, 96 int64_t offset, int bytes) 97 { 98 return bdrv_co_pdiscard(bs->file, offset, bytes); 99 } 100 101 102 static void compress_refresh_limits(BlockDriverState *bs, Error **errp) 103 { 104 BlockDriverInfo bdi; 105 int ret; 106 107 if (!bs->file) { 108 return; 109 } 110 111 ret = bdrv_get_info(bs->file->bs, &bdi); 112 if (ret < 0 || bdi.cluster_size == 0) { 113 return; 114 } 115 116 bs->bl.request_alignment = bdi.cluster_size; 117 } 118 119 120 static void compress_eject(BlockDriverState *bs, bool eject_flag) 121 { 122 bdrv_eject(bs->file->bs, eject_flag); 123 } 124 125 126 static void compress_lock_medium(BlockDriverState *bs, bool locked) 127 { 128 bdrv_lock_medium(bs->file->bs, locked); 129 } 130 131 132 static BlockDriver bdrv_compress = { 133 .format_name = "compress", 134 135 .bdrv_open = compress_open, 136 .bdrv_child_perm = bdrv_default_perms, 137 138 .bdrv_getlength = compress_getlength, 139 140 .bdrv_co_preadv_part = compress_co_preadv_part, 141 .bdrv_co_pwritev_part = compress_co_pwritev_part, 142 .bdrv_co_pwrite_zeroes = compress_co_pwrite_zeroes, 143 .bdrv_co_pdiscard = compress_co_pdiscard, 144 .bdrv_refresh_limits = compress_refresh_limits, 145 146 .bdrv_eject = compress_eject, 147 .bdrv_lock_medium = compress_lock_medium, 148 149 .has_variable_length = true, 150 .is_filter = true, 151 }; 152 153 static void bdrv_compress_init(void) 154 { 155 bdrv_register(&bdrv_compress); 156 } 157 158 block_init(bdrv_compress_init); 159