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
compress_open(BlockDriverState * bs,QDict * options,int flags,Error ** errp)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
compress_co_getlength(BlockDriverState * bs)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
compress_co_preadv_part(BlockDriverState * bs,int64_t offset,int64_t bytes,QEMUIOVector * qiov,size_t qiov_offset,BdrvRequestFlags flags)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
compress_co_pwritev_part(BlockDriverState * bs,int64_t offset,int64_t bytes,QEMUIOVector * qiov,size_t qiov_offset,BdrvRequestFlags flags)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
compress_co_pwrite_zeroes(BlockDriverState * bs,int64_t offset,int64_t bytes,BdrvRequestFlags flags)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
compress_co_pdiscard(BlockDriverState * bs,int64_t offset,int64_t bytes)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
compress_refresh_limits(BlockDriverState * bs,Error ** errp)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
compress_co_eject(BlockDriverState * bs,bool eject_flag)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
compress_co_lock_medium(BlockDriverState * bs,bool locked)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
bdrv_compress_init(void)155 static void bdrv_compress_init(void)
156 {
157 bdrv_register(&bdrv_compress);
158 }
159
160 block_init(bdrv_compress_init);
161