diff options
Diffstat (limited to 'e2fsprogs/ext2fs/rw_bitmaps.c')
-rw-r--r-- | e2fsprogs/ext2fs/rw_bitmaps.c | 296 |
1 files changed, 296 insertions, 0 deletions
diff --git a/e2fsprogs/ext2fs/rw_bitmaps.c b/e2fsprogs/ext2fs/rw_bitmaps.c new file mode 100644 index 000000000..a5782db95 --- /dev/null +++ b/e2fsprogs/ext2fs/rw_bitmaps.c | |||
@@ -0,0 +1,296 @@ | |||
1 | /* vi: set sw=4 ts=4: */ | ||
2 | /* | ||
3 | * rw_bitmaps.c --- routines to read and write the inode and block bitmaps. | ||
4 | * | ||
5 | * Copyright (C) 1993, 1994, 1994, 1996 Theodore Ts'o. | ||
6 | * | ||
7 | * %Begin-Header% | ||
8 | * This file may be redistributed under the terms of the GNU Public | ||
9 | * License. | ||
10 | * %End-Header% | ||
11 | */ | ||
12 | |||
13 | #include <stdio.h> | ||
14 | #include <string.h> | ||
15 | #if HAVE_UNISTD_H | ||
16 | #include <unistd.h> | ||
17 | #endif | ||
18 | #include <fcntl.h> | ||
19 | #include <time.h> | ||
20 | #ifdef HAVE_SYS_STAT_H | ||
21 | #include <sys/stat.h> | ||
22 | #endif | ||
23 | #ifdef HAVE_SYS_TYPES_H | ||
24 | #include <sys/types.h> | ||
25 | #endif | ||
26 | |||
27 | #include "ext2_fs.h" | ||
28 | #include "ext2fs.h" | ||
29 | #include "e2image.h" | ||
30 | |||
31 | #if defined(__powerpc__) && BB_BIG_ENDIAN | ||
32 | /* | ||
33 | * On the PowerPC, the big-endian variant of the ext2 filesystem | ||
34 | * has its bitmaps stored as 32-bit words with bit 0 as the LSB | ||
35 | * of each word. Thus a bitmap with only bit 0 set would be, as | ||
36 | * a string of bytes, 00 00 00 01 00 ... | ||
37 | * To cope with this, we byte-reverse each word of a bitmap if | ||
38 | * we have a big-endian filesystem, that is, if we are *not* | ||
39 | * byte-swapping other word-sized numbers. | ||
40 | */ | ||
41 | #define EXT2_BIG_ENDIAN_BITMAPS | ||
42 | #endif | ||
43 | |||
44 | #ifdef EXT2_BIG_ENDIAN_BITMAPS | ||
45 | static void ext2fs_swap_bitmap(ext2_filsys fs, char *bitmap, int nbytes) | ||
46 | { | ||
47 | __u32 *p = (__u32 *) bitmap; | ||
48 | int n; | ||
49 | |||
50 | for (n = nbytes / sizeof(__u32); n > 0; --n, ++p) | ||
51 | *p = ext2fs_swab32(*p); | ||
52 | } | ||
53 | #endif | ||
54 | |||
55 | errcode_t ext2fs_write_inode_bitmap(ext2_filsys fs) | ||
56 | { | ||
57 | dgrp_t i; | ||
58 | size_t nbytes; | ||
59 | errcode_t retval; | ||
60 | char * inode_bitmap = fs->inode_map->bitmap; | ||
61 | char * bitmap_block = NULL; | ||
62 | blk_t blk; | ||
63 | |||
64 | EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); | ||
65 | |||
66 | if (!(fs->flags & EXT2_FLAG_RW)) | ||
67 | return EXT2_ET_RO_FILSYS; | ||
68 | if (!inode_bitmap) | ||
69 | return 0; | ||
70 | nbytes = (size_t) ((EXT2_INODES_PER_GROUP(fs->super)+7) / 8); | ||
71 | |||
72 | retval = ext2fs_get_mem(fs->blocksize, &bitmap_block); | ||
73 | if (retval) | ||
74 | return retval; | ||
75 | memset(bitmap_block, 0xff, fs->blocksize); | ||
76 | for (i = 0; i < fs->group_desc_count; i++) { | ||
77 | memcpy(bitmap_block, inode_bitmap, nbytes); | ||
78 | blk = fs->group_desc[i].bg_inode_bitmap; | ||
79 | if (blk) { | ||
80 | #ifdef EXT2_BIG_ENDIAN_BITMAPS | ||
81 | if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) || | ||
82 | (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))) | ||
83 | ext2fs_swap_bitmap(fs, bitmap_block, nbytes); | ||
84 | #endif | ||
85 | retval = io_channel_write_blk(fs->io, blk, 1, | ||
86 | bitmap_block); | ||
87 | if (retval) | ||
88 | return EXT2_ET_INODE_BITMAP_WRITE; | ||
89 | } | ||
90 | inode_bitmap += nbytes; | ||
91 | } | ||
92 | fs->flags &= ~EXT2_FLAG_IB_DIRTY; | ||
93 | ext2fs_free_mem(&bitmap_block); | ||
94 | return 0; | ||
95 | } | ||
96 | |||
97 | errcode_t ext2fs_write_block_bitmap (ext2_filsys fs) | ||
98 | { | ||
99 | dgrp_t i; | ||
100 | unsigned int j; | ||
101 | int nbytes; | ||
102 | unsigned int nbits; | ||
103 | errcode_t retval; | ||
104 | char * block_bitmap = fs->block_map->bitmap; | ||
105 | char * bitmap_block = NULL; | ||
106 | blk_t blk; | ||
107 | |||
108 | EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); | ||
109 | |||
110 | if (!(fs->flags & EXT2_FLAG_RW)) | ||
111 | return EXT2_ET_RO_FILSYS; | ||
112 | if (!block_bitmap) | ||
113 | return 0; | ||
114 | nbytes = EXT2_BLOCKS_PER_GROUP(fs->super) / 8; | ||
115 | retval = ext2fs_get_mem(fs->blocksize, &bitmap_block); | ||
116 | if (retval) | ||
117 | return retval; | ||
118 | memset(bitmap_block, 0xff, fs->blocksize); | ||
119 | for (i = 0; i < fs->group_desc_count; i++) { | ||
120 | memcpy(bitmap_block, block_bitmap, nbytes); | ||
121 | if (i == fs->group_desc_count - 1) { | ||
122 | /* Force bitmap padding for the last group */ | ||
123 | nbits = ((fs->super->s_blocks_count | ||
124 | - fs->super->s_first_data_block) | ||
125 | % EXT2_BLOCKS_PER_GROUP(fs->super)); | ||
126 | if (nbits) | ||
127 | for (j = nbits; j < fs->blocksize * 8; j++) | ||
128 | ext2fs_set_bit(j, bitmap_block); | ||
129 | } | ||
130 | blk = fs->group_desc[i].bg_block_bitmap; | ||
131 | if (blk) { | ||
132 | #ifdef EXT2_BIG_ENDIAN_BITMAPS | ||
133 | if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) || | ||
134 | (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))) | ||
135 | ext2fs_swap_bitmap(fs, bitmap_block, nbytes); | ||
136 | #endif | ||
137 | retval = io_channel_write_blk(fs->io, blk, 1, | ||
138 | bitmap_block); | ||
139 | if (retval) | ||
140 | return EXT2_ET_BLOCK_BITMAP_WRITE; | ||
141 | } | ||
142 | block_bitmap += nbytes; | ||
143 | } | ||
144 | fs->flags &= ~EXT2_FLAG_BB_DIRTY; | ||
145 | ext2fs_free_mem(&bitmap_block); | ||
146 | return 0; | ||
147 | } | ||
148 | |||
149 | static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block) | ||
150 | { | ||
151 | dgrp_t i; | ||
152 | char *block_bitmap = 0, *inode_bitmap = 0; | ||
153 | char *buf; | ||
154 | errcode_t retval; | ||
155 | int block_nbytes = (int) EXT2_BLOCKS_PER_GROUP(fs->super) / 8; | ||
156 | int inode_nbytes = (int) EXT2_INODES_PER_GROUP(fs->super) / 8; | ||
157 | blk_t blk; | ||
158 | |||
159 | EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); | ||
160 | |||
161 | fs->write_bitmaps = ext2fs_write_bitmaps; | ||
162 | |||
163 | retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf); | ||
164 | if (retval) | ||
165 | return retval; | ||
166 | if (do_block) { | ||
167 | ext2fs_free_block_bitmap(fs->block_map); | ||
168 | sprintf(buf, "block bitmap for %s", fs->device_name); | ||
169 | retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map); | ||
170 | if (retval) | ||
171 | goto cleanup; | ||
172 | block_bitmap = fs->block_map->bitmap; | ||
173 | } | ||
174 | if (do_inode) { | ||
175 | ext2fs_free_inode_bitmap(fs->inode_map); | ||
176 | sprintf(buf, "inode bitmap for %s", fs->device_name); | ||
177 | retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map); | ||
178 | if (retval) | ||
179 | goto cleanup; | ||
180 | inode_bitmap = fs->inode_map->bitmap; | ||
181 | } | ||
182 | ext2fs_free_mem(&buf); | ||
183 | |||
184 | if (fs->flags & EXT2_FLAG_IMAGE_FILE) { | ||
185 | if (inode_bitmap) { | ||
186 | blk = (fs->image_header->offset_inodemap / | ||
187 | fs->blocksize); | ||
188 | retval = io_channel_read_blk(fs->image_io, blk, | ||
189 | -(inode_nbytes * fs->group_desc_count), | ||
190 | inode_bitmap); | ||
191 | if (retval) | ||
192 | goto cleanup; | ||
193 | } | ||
194 | if (block_bitmap) { | ||
195 | blk = (fs->image_header->offset_blockmap / | ||
196 | fs->blocksize); | ||
197 | retval = io_channel_read_blk(fs->image_io, blk, | ||
198 | -(block_nbytes * fs->group_desc_count), | ||
199 | block_bitmap); | ||
200 | if (retval) | ||
201 | goto cleanup; | ||
202 | } | ||
203 | return 0; | ||
204 | } | ||
205 | |||
206 | for (i = 0; i < fs->group_desc_count; i++) { | ||
207 | if (block_bitmap) { | ||
208 | blk = fs->group_desc[i].bg_block_bitmap; | ||
209 | if (blk) { | ||
210 | retval = io_channel_read_blk(fs->io, blk, | ||
211 | -block_nbytes, block_bitmap); | ||
212 | if (retval) { | ||
213 | retval = EXT2_ET_BLOCK_BITMAP_READ; | ||
214 | goto cleanup; | ||
215 | } | ||
216 | #ifdef EXT2_BIG_ENDIAN_BITMAPS | ||
217 | if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) || | ||
218 | (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))) | ||
219 | ext2fs_swap_bitmap(fs, block_bitmap, block_nbytes); | ||
220 | #endif | ||
221 | } else | ||
222 | memset(block_bitmap, 0, block_nbytes); | ||
223 | block_bitmap += block_nbytes; | ||
224 | } | ||
225 | if (inode_bitmap) { | ||
226 | blk = fs->group_desc[i].bg_inode_bitmap; | ||
227 | if (blk) { | ||
228 | retval = io_channel_read_blk(fs->io, blk, | ||
229 | -inode_nbytes, inode_bitmap); | ||
230 | if (retval) { | ||
231 | retval = EXT2_ET_INODE_BITMAP_READ; | ||
232 | goto cleanup; | ||
233 | } | ||
234 | #ifdef EXT2_BIG_ENDIAN_BITMAPS | ||
235 | if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) || | ||
236 | (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))) | ||
237 | ext2fs_swap_bitmap(fs, inode_bitmap, inode_nbytes); | ||
238 | #endif | ||
239 | } else | ||
240 | memset(inode_bitmap, 0, inode_nbytes); | ||
241 | inode_bitmap += inode_nbytes; | ||
242 | } | ||
243 | } | ||
244 | return 0; | ||
245 | |||
246 | cleanup: | ||
247 | if (do_block) { | ||
248 | ext2fs_free_mem(&fs->block_map); | ||
249 | } | ||
250 | if (do_inode) { | ||
251 | ext2fs_free_mem(&fs->inode_map); | ||
252 | } | ||
253 | ext2fs_free_mem(&buf); | ||
254 | return retval; | ||
255 | } | ||
256 | |||
257 | errcode_t ext2fs_read_inode_bitmap (ext2_filsys fs) | ||
258 | { | ||
259 | return read_bitmaps(fs, 1, 0); | ||
260 | } | ||
261 | |||
262 | errcode_t ext2fs_read_block_bitmap(ext2_filsys fs) | ||
263 | { | ||
264 | return read_bitmaps(fs, 0, 1); | ||
265 | } | ||
266 | |||
267 | errcode_t ext2fs_read_bitmaps(ext2_filsys fs) | ||
268 | { | ||
269 | |||
270 | EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); | ||
271 | |||
272 | if (fs->inode_map && fs->block_map) | ||
273 | return 0; | ||
274 | |||
275 | return read_bitmaps(fs, !fs->inode_map, !fs->block_map); | ||
276 | } | ||
277 | |||
278 | errcode_t ext2fs_write_bitmaps(ext2_filsys fs) | ||
279 | { | ||
280 | errcode_t retval; | ||
281 | |||
282 | EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); | ||
283 | |||
284 | if (fs->block_map && ext2fs_test_bb_dirty(fs)) { | ||
285 | retval = ext2fs_write_block_bitmap(fs); | ||
286 | if (retval) | ||
287 | return retval; | ||
288 | } | ||
289 | if (fs->inode_map && ext2fs_test_ib_dirty(fs)) { | ||
290 | retval = ext2fs_write_inode_bitmap(fs); | ||
291 | if (retval) | ||
292 | return retval; | ||
293 | } | ||
294 | return 0; | ||
295 | } | ||
296 | |||