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-io.h" 26 #include "block/block_int.h" 27 #include "qemu/module.h" 28 #include "qapi/error.h" 29 30 31 static int compress_open(BlockDriverState *bs, QDict *options, int flags, 32 Error **errp) 33 { 34 int ret = bdrv_open_file_child(NULL, options, "file", bs, errp); 35 if (ret < 0) { 36 return ret; 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 coroutine_fn GRAPH_RDLOCK 59 compress_co_getlength(BlockDriverState *bs) 60 { 61 return bdrv_co_getlength(bs->file->bs); 62 } 63 64 65 static int coroutine_fn GRAPH_RDLOCK 66 compress_co_preadv_part(BlockDriverState *bs, int64_t offset, int64_t bytes, 67 QEMUIOVector *qiov, size_t qiov_offset, 68 BdrvRequestFlags 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 GRAPH_RDLOCK 76 compress_co_pwritev_part(BlockDriverState *bs, int64_t offset, int64_t bytes, 77 QEMUIOVector *qiov, size_t qiov_offset, 78 BdrvRequestFlags flags) 79 { 80 return bdrv_co_pwritev_part(bs->file, offset, bytes, qiov, qiov_offset, 81 flags | BDRV_REQ_WRITE_COMPRESSED); 82 } 83 84 85 static int coroutine_fn GRAPH_RDLOCK 86 compress_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int64_t bytes, 87 BdrvRequestFlags flags) 88 { 89 return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags); 90 } 91 92 93 static int coroutine_fn GRAPH_RDLOCK 94 compress_co_pdiscard(BlockDriverState *bs, int64_t offset, int64_t bytes) 95 { 96 return bdrv_co_pdiscard(bs->file, offset, bytes); 97 } 98 99 100 static void compress_refresh_limits(BlockDriverState *bs, Error **errp) 101 { 102 BlockDriverInfo bdi; 103 int ret; 104 105 if (!bs->file) { 106 return; 107 } 108 109 ret = bdrv_get_info(bs->file->bs, &bdi); 110 if (ret < 0 || bdi.cluster_size == 0) { 111 return; 112 } 113 114 bs->bl.request_alignment = bdi.cluster_size; 115 } 116 117 118 static void coroutine_fn GRAPH_RDLOCK 119 compress_co_eject(BlockDriverState *bs, bool eject_flag) 120 { 121 bdrv_co_eject(bs->file->bs, eject_flag); 122 } 123 124 125 static void coroutine_fn GRAPH_RDLOCK 126 compress_co_lock_medium(BlockDriverState *bs, bool locked) 127 { 128 bdrv_co_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_co_getlength = compress_co_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_co_eject = compress_co_eject, 147 .bdrv_co_lock_medium = compress_co_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