]>
Commit | Line | Data |
---|---|---|
6c6f24fd HR |
1 | /* |
2 | * Copy-on-read filter block driver | |
3 | * | |
4 | * Copyright (c) 2018 Red Hat, Inc. | |
5 | * | |
6 | * Author: | |
7 | * Max Reitz <mreitz@redhat.com> | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU General Public License as | |
11 | * published by the Free Software Foundation; either version 2 or | |
12 | * (at your option) version 3 of the License. | |
13 | * | |
14 | * This program is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | * GNU General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License | |
20 | * along with this program; if not, see <http://www.gnu.org/licenses/>. | |
21 | */ | |
22 | ||
23 | #include "qemu/osdep.h" | |
24 | #include "block/block_int.h" | |
25 | ||
26 | ||
27 | static int cor_open(BlockDriverState *bs, QDict *options, int flags, | |
28 | Error **errp) | |
29 | { | |
30 | bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, false, | |
31 | errp); | |
32 | if (!bs->file) { | |
33 | return -EINVAL; | |
34 | } | |
35 | ||
228345bf HR |
36 | bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED | |
37 | (BDRV_REQ_FUA & | |
38 | bs->file->bs->supported_write_flags); | |
6c6f24fd | 39 | |
228345bf HR |
40 | bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED | |
41 | ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP) & | |
42 | bs->file->bs->supported_zero_flags); | |
6c6f24fd HR |
43 | |
44 | return 0; | |
45 | } | |
46 | ||
47 | ||
48 | static void cor_close(BlockDriverState *bs) | |
49 | { | |
50 | } | |
51 | ||
52 | ||
53 | #define PERM_PASSTHROUGH (BLK_PERM_CONSISTENT_READ \ | |
54 | | BLK_PERM_WRITE \ | |
55 | | BLK_PERM_RESIZE) | |
56 | #define PERM_UNCHANGED (BLK_PERM_ALL & ~PERM_PASSTHROUGH) | |
57 | ||
58 | static void cor_child_perm(BlockDriverState *bs, BdrvChild *c, | |
59 | const BdrvChildRole *role, | |
60 | BlockReopenQueue *reopen_queue, | |
61 | uint64_t perm, uint64_t shared, | |
62 | uint64_t *nperm, uint64_t *nshared) | |
63 | { | |
64 | if (c == NULL) { | |
65 | *nperm = (perm & PERM_PASSTHROUGH) | BLK_PERM_WRITE_UNCHANGED; | |
66 | *nshared = (shared & PERM_PASSTHROUGH) | PERM_UNCHANGED; | |
67 | return; | |
68 | } | |
69 | ||
70 | *nperm = (perm & PERM_PASSTHROUGH) | | |
71 | (c->perm & PERM_UNCHANGED); | |
72 | *nshared = (shared & PERM_PASSTHROUGH) | | |
73 | (c->shared_perm & PERM_UNCHANGED); | |
74 | } | |
75 | ||
76 | ||
77 | static int64_t cor_getlength(BlockDriverState *bs) | |
78 | { | |
79 | return bdrv_getlength(bs->file->bs); | |
80 | } | |
81 | ||
82 | ||
061ca8a3 KW |
83 | static int coroutine_fn cor_co_truncate(BlockDriverState *bs, int64_t offset, |
84 | PreallocMode prealloc, Error **errp) | |
6c6f24fd | 85 | { |
061ca8a3 | 86 | return bdrv_co_truncate(bs->file, offset, prealloc, errp); |
6c6f24fd HR |
87 | } |
88 | ||
89 | ||
90 | static int coroutine_fn cor_co_preadv(BlockDriverState *bs, | |
91 | uint64_t offset, uint64_t bytes, | |
92 | QEMUIOVector *qiov, int flags) | |
93 | { | |
94 | return bdrv_co_preadv(bs->file, offset, bytes, qiov, | |
95 | flags | BDRV_REQ_COPY_ON_READ); | |
96 | } | |
97 | ||
98 | ||
99 | static int coroutine_fn cor_co_pwritev(BlockDriverState *bs, | |
100 | uint64_t offset, uint64_t bytes, | |
101 | QEMUIOVector *qiov, int flags) | |
102 | { | |
103 | ||
104 | return bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags); | |
105 | } | |
106 | ||
107 | ||
108 | static int coroutine_fn cor_co_pwrite_zeroes(BlockDriverState *bs, | |
109 | int64_t offset, int bytes, | |
110 | BdrvRequestFlags flags) | |
111 | { | |
112 | return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags); | |
113 | } | |
114 | ||
115 | ||
116 | static int coroutine_fn cor_co_pdiscard(BlockDriverState *bs, | |
117 | int64_t offset, int bytes) | |
118 | { | |
119 | return bdrv_co_pdiscard(bs->file->bs, offset, bytes); | |
120 | } | |
121 | ||
122 | ||
123 | static void cor_eject(BlockDriverState *bs, bool eject_flag) | |
124 | { | |
125 | bdrv_eject(bs->file->bs, eject_flag); | |
126 | } | |
127 | ||
128 | ||
129 | static void cor_lock_medium(BlockDriverState *bs, bool locked) | |
130 | { | |
131 | bdrv_lock_medium(bs->file->bs, locked); | |
132 | } | |
133 | ||
134 | ||
135 | static bool cor_recurse_is_first_non_filter(BlockDriverState *bs, | |
136 | BlockDriverState *candidate) | |
137 | { | |
138 | return bdrv_recurse_is_first_non_filter(bs->file->bs, candidate); | |
139 | } | |
140 | ||
141 | ||
142 | BlockDriver bdrv_copy_on_read = { | |
143 | .format_name = "copy-on-read", | |
144 | ||
145 | .bdrv_open = cor_open, | |
146 | .bdrv_close = cor_close, | |
147 | .bdrv_child_perm = cor_child_perm, | |
148 | ||
149 | .bdrv_getlength = cor_getlength, | |
061ca8a3 | 150 | .bdrv_co_truncate = cor_co_truncate, |
6c6f24fd HR |
151 | |
152 | .bdrv_co_preadv = cor_co_preadv, | |
153 | .bdrv_co_pwritev = cor_co_pwritev, | |
154 | .bdrv_co_pwrite_zeroes = cor_co_pwrite_zeroes, | |
155 | .bdrv_co_pdiscard = cor_co_pdiscard, | |
156 | ||
157 | .bdrv_eject = cor_eject, | |
158 | .bdrv_lock_medium = cor_lock_medium, | |
159 | ||
160 | .bdrv_co_block_status = bdrv_co_block_status_from_file, | |
161 | ||
162 | .bdrv_recurse_is_first_non_filter = cor_recurse_is_first_non_filter, | |
163 | ||
164 | .has_variable_length = true, | |
165 | .is_filter = true, | |
166 | }; | |
167 | ||
168 | static void bdrv_copy_on_read_init(void) | |
169 | { | |
170 | bdrv_register(&bdrv_copy_on_read); | |
171 | } | |
172 | ||
173 | block_init(bdrv_copy_on_read_init); |