blob: bba4326796d3d7af1708b14a9c8e4457b5325d5f
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 = NULL, *inode_bitmap = NULL; |
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 | EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
270 | |
271 | if (fs->inode_map && fs->block_map) |
272 | return 0; |
273 | |
274 | return read_bitmaps(fs, !fs->inode_map, !fs->block_map); |
275 | } |
276 | |
277 | errcode_t ext2fs_write_bitmaps(ext2_filsys fs) |
278 | { |
279 | errcode_t retval; |
280 | |
281 | EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
282 | |
283 | if (fs->block_map && ext2fs_test_bb_dirty(fs)) { |
284 | retval = ext2fs_write_block_bitmap(fs); |
285 | if (retval) |
286 | return retval; |
287 | } |
288 | if (fs->inode_map && ext2fs_test_ib_dirty(fs)) { |
289 | retval = ext2fs_write_inode_bitmap(fs); |
290 | if (retval) |
291 | return retval; |
292 | } |
293 | return 0; |
294 | } |
295 |