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 GRAPH_RDLOCK_GUARD_MAINLOOP(); 40 41 if (!bs->file->bs->drv || !block_driver_can_compress(bs->file->bs->drv)) { 42 error_setg(errp, 43 "Compression is not supported for underlying format: %s", 44 bdrv_get_format_name(bs->file->bs) ?: "(no format)"); 45 46 return -ENOTSUP; 47 } 48 49 bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED | 50 (BDRV_REQ_FUA & bs->file->bs->supported_write_flags); 51 52 bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED | 53 ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) & 54 bs->file->bs->supported_zero_flags); 55 56 return 0; 57 } 58 59 60 static int64_t coroutine_fn GRAPH_RDLOCK 61 compress_co_getlength(BlockDriverState *bs) 62 { 63 return bdrv_co_getlength(bs->file->bs); 64 } 65 66 67 static int coroutine_fn GRAPH_RDLOCK 68 compress_co_preadv_part(BlockDriverState *bs, int64_t offset, int64_t bytes, 69 QEMUIOVector *qiov, size_t qiov_offset, 70 BdrvRequestFlags flags) 71 { 72 return bdrv_co_preadv_part(bs->file, offset, bytes, qiov, qiov_offset, 73 flags); 74 } 75 76 77 static int coroutine_fn GRAPH_RDLOCK 78 compress_co_pwritev_part(BlockDriverState *bs, int64_t offset, int64_t bytes, 79 QEMUIOVector *qiov, size_t qiov_offset, 80 BdrvRequestFlags 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 GRAPH_RDLOCK 88 compress_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int64_t bytes, 89 BdrvRequestFlags flags) 90 { 91 return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags); 92 } 93 94 95 static int coroutine_fn GRAPH_RDLOCK 96 compress_co_pdiscard(BlockDriverState *bs, int64_t offset, int64_t bytes) 97 { 98 return bdrv_co_pdiscard(bs->file, offset, bytes); 99 } 100 101 102 static void GRAPH_RDLOCK 103 compress_refresh_limits(BlockDriverState *bs, Error **errp) 104 { 105 BlockDriverInfo bdi; 106 int ret; 107 108 if (!bs->file) { 109 return; 110 } 111 112 ret = bdrv_get_info(bs->file->bs, &bdi); 113 if (ret < 0 || bdi.cluster_size == 0) { 114 return; 115 } 116 117 bs->bl.request_alignment = bdi.cluster_size; 118 } 119 120 121 static void coroutine_fn GRAPH_RDLOCK 122 compress_co_eject(BlockDriverState *bs, bool eject_flag) 123 { 124 bdrv_co_eject(bs->file->bs, eject_flag); 125 } 126 127 128 static void coroutine_fn GRAPH_RDLOCK 129 compress_co_lock_medium(BlockDriverState *bs, bool locked) 130 { 131 bdrv_co_lock_medium(bs->file->bs, locked); 132 } 133 134 135 static BlockDriver bdrv_compress = { 136 .format_name = "compress", 137 138 .bdrv_open = compress_open, 139 .bdrv_child_perm = bdrv_default_perms, 140 141 .bdrv_co_getlength = compress_co_getlength, 142 143 .bdrv_co_preadv_part = compress_co_preadv_part, 144 .bdrv_co_pwritev_part = compress_co_pwritev_part, 145 .bdrv_co_pwrite_zeroes = compress_co_pwrite_zeroes, 146 .bdrv_co_pdiscard = compress_co_pdiscard, 147 .bdrv_refresh_limits = compress_refresh_limits, 148 149 .bdrv_co_eject = compress_co_eject, 150 .bdrv_co_lock_medium = compress_co_lock_medium, 151 152 .is_filter = true, 153 }; 154 155 static void bdrv_compress_init(void) 156 { 157 bdrv_register(&bdrv_compress); 158 } 159 160 block_init(bdrv_compress_init); 161