ia64/xen-unstable

view tools/ioemu/block-cow.c @ 15841:c5f735271e22

[IA64] Foreign p2m: Fix vti domain builder.

It should set arch_domain::convmem_end.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
author Alex Williamson <alex.williamson@hp.com>
date Thu Sep 06 13:48:43 2007 -0600 (2007-09-06)
parents 00618037d37d
children 24f23a89f86c
line source
1 /*
2 * Block driver for the COW format
3 *
4 * Copyright (c) 2004 Fabrice Bellard
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
23 */
24 #ifndef _WIN32
25 #include "vl.h"
26 #include "block_int.h"
27 #include <sys/mman.h>
29 /**************************************************************/
30 /* COW block driver using file system holes */
32 /* user mode linux compatible COW file */
33 #define COW_MAGIC 0x4f4f4f4d /* MOOO */
34 #define COW_VERSION 2
36 struct cow_header_v2 {
37 uint32_t magic;
38 uint32_t version;
39 char backing_file[1024];
40 int32_t mtime;
41 uint64_t size;
42 uint32_t sectorsize;
43 };
45 typedef struct BDRVCowState {
46 int fd;
47 uint8_t *cow_bitmap; /* if non NULL, COW mappings are used first */
48 uint8_t *cow_bitmap_addr; /* mmap address of cow_bitmap */
49 int cow_bitmap_size;
50 int64_t cow_sectors_offset;
51 } BDRVCowState;
53 static int cow_probe(const uint8_t *buf, int buf_size, const char *filename)
54 {
55 const struct cow_header_v2 *cow_header = (const void *)buf;
57 if (buf_size >= sizeof(struct cow_header_v2) &&
58 be32_to_cpu(cow_header->magic) == COW_MAGIC &&
59 be32_to_cpu(cow_header->version) == COW_VERSION)
60 return 100;
61 else
62 return 0;
63 }
65 static int cow_open(BlockDriverState *bs, const char *filename, int flags)
66 {
67 BDRVCowState *s = bs->opaque;
68 int fd;
69 struct cow_header_v2 cow_header;
70 int64_t size;
72 fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE);
73 if (fd < 0) {
74 fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
75 if (fd < 0)
76 return -1;
77 }
78 s->fd = fd;
79 /* see if it is a cow image */
80 if (read(fd, &cow_header, sizeof(cow_header)) != sizeof(cow_header)) {
81 goto fail;
82 }
84 if (be32_to_cpu(cow_header.magic) != COW_MAGIC ||
85 be32_to_cpu(cow_header.version) != COW_VERSION) {
86 goto fail;
87 }
89 /* cow image found */
90 size = be64_to_cpu(cow_header.size);
91 bs->total_sectors = size / 512;
93 pstrcpy(bs->backing_file, sizeof(bs->backing_file),
94 cow_header.backing_file);
96 /* mmap the bitmap */
97 s->cow_bitmap_size = ((bs->total_sectors + 7) >> 3) + sizeof(cow_header);
98 s->cow_bitmap_addr = mmap(get_mmap_addr(s->cow_bitmap_size),
99 s->cow_bitmap_size,
100 PROT_READ | PROT_WRITE,
101 MAP_SHARED, s->fd, 0);
102 if (s->cow_bitmap_addr == MAP_FAILED)
103 goto fail;
104 s->cow_bitmap = s->cow_bitmap_addr + sizeof(cow_header);
105 s->cow_sectors_offset = (s->cow_bitmap_size + 511) & ~511;
106 return 0;
107 fail:
108 close(fd);
109 return -1;
110 }
112 static inline void cow_set_bit(uint8_t *bitmap, int64_t bitnum)
113 {
114 bitmap[bitnum / 8] |= (1 << (bitnum%8));
115 }
117 static inline int is_bit_set(const uint8_t *bitmap, int64_t bitnum)
118 {
119 return !!(bitmap[bitnum / 8] & (1 << (bitnum%8)));
120 }
123 /* Return true if first block has been changed (ie. current version is
124 * in COW file). Set the number of continuous blocks for which that
125 * is true. */
126 static inline int is_changed(uint8_t *bitmap,
127 int64_t sector_num, int nb_sectors,
128 int *num_same)
129 {
130 int changed;
132 if (!bitmap || nb_sectors == 0) {
133 *num_same = nb_sectors;
134 return 0;
135 }
137 changed = is_bit_set(bitmap, sector_num);
138 for (*num_same = 1; *num_same < nb_sectors; (*num_same)++) {
139 if (is_bit_set(bitmap, sector_num + *num_same) != changed)
140 break;
141 }
143 return changed;
144 }
146 static int cow_is_allocated(BlockDriverState *bs, int64_t sector_num,
147 int nb_sectors, int *pnum)
148 {
149 BDRVCowState *s = bs->opaque;
150 return is_changed(s->cow_bitmap, sector_num, nb_sectors, pnum);
151 }
153 static int cow_read(BlockDriverState *bs, int64_t sector_num,
154 uint8_t *buf, int nb_sectors)
155 {
156 BDRVCowState *s = bs->opaque;
157 int ret, n;
159 while (nb_sectors > 0) {
160 if (is_changed(s->cow_bitmap, sector_num, nb_sectors, &n)) {
161 lseek(s->fd, s->cow_sectors_offset + sector_num * 512, SEEK_SET);
162 ret = read(s->fd, buf, n * 512);
163 if (ret != n * 512)
164 return -1;
165 } else {
166 if (bs->backing_hd) {
167 /* read from the base image */
168 ret = bdrv_read(bs->backing_hd, sector_num, buf, n);
169 if (ret < 0)
170 return -1;
171 } else {
172 memset(buf, 0, n * 512);
173 }
174 }
175 nb_sectors -= n;
176 sector_num += n;
177 buf += n * 512;
178 }
179 return 0;
180 }
182 static int cow_write(BlockDriverState *bs, int64_t sector_num,
183 const uint8_t *buf, int nb_sectors)
184 {
185 BDRVCowState *s = bs->opaque;
186 int ret, i;
188 lseek(s->fd, s->cow_sectors_offset + sector_num * 512, SEEK_SET);
189 ret = write(s->fd, buf, nb_sectors * 512);
190 if (ret != nb_sectors * 512)
191 return -1;
192 for (i = 0; i < nb_sectors; i++)
193 cow_set_bit(s->cow_bitmap, sector_num + i);
194 return 0;
195 }
197 static void cow_close(BlockDriverState *bs)
198 {
199 BDRVCowState *s = bs->opaque;
200 munmap(s->cow_bitmap_addr, s->cow_bitmap_size);
201 close(s->fd);
202 }
204 static int cow_create(const char *filename, int64_t image_sectors,
205 const char *image_filename, int flags)
206 {
207 int fd, cow_fd;
208 struct cow_header_v2 cow_header;
209 struct stat st;
211 if (flags)
212 return -ENOTSUP;
214 cow_fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
215 0644);
216 if (cow_fd < 0)
217 return -1;
218 memset(&cow_header, 0, sizeof(cow_header));
219 cow_header.magic = cpu_to_be32(COW_MAGIC);
220 cow_header.version = cpu_to_be32(COW_VERSION);
221 if (image_filename) {
222 /* Note: if no file, we put a dummy mtime */
223 cow_header.mtime = cpu_to_be32(0);
225 fd = open(image_filename, O_RDONLY | O_BINARY);
226 if (fd < 0) {
227 close(cow_fd);
228 goto mtime_fail;
229 }
230 if (fstat(fd, &st) != 0) {
231 close(fd);
232 goto mtime_fail;
233 }
234 close(fd);
235 cow_header.mtime = cpu_to_be32(st.st_mtime);
236 mtime_fail:
237 pstrcpy(cow_header.backing_file, sizeof(cow_header.backing_file),
238 image_filename);
239 }
240 cow_header.sectorsize = cpu_to_be32(512);
241 cow_header.size = cpu_to_be64(image_sectors * 512);
242 write(cow_fd, &cow_header, sizeof(cow_header));
243 /* resize to include at least all the bitmap */
244 ftruncate(cow_fd, sizeof(cow_header) + ((image_sectors + 7) >> 3));
245 close(cow_fd);
246 return 0;
247 }
249 static void cow_flush(BlockDriverState *bs)
250 {
251 BDRVCowState *s = bs->opaque;
252 fsync(s->fd);
253 }
255 BlockDriver bdrv_cow = {
256 "cow",
257 sizeof(BDRVCowState),
258 cow_probe,
259 cow_open,
260 cow_read,
261 cow_write,
262 cow_close,
263 cow_create,
264 cow_flush,
265 cow_is_allocated,
266 };
267 #endif