diff options
Diffstat (limited to 'e2fsprogs/ext2fs/bmap.c')
-rw-r--r-- | e2fsprogs/ext2fs/bmap.c | 264 |
1 files changed, 264 insertions, 0 deletions
diff --git a/e2fsprogs/ext2fs/bmap.c b/e2fsprogs/ext2fs/bmap.c new file mode 100644 index 000000000..b22fe3dbf --- /dev/null +++ b/e2fsprogs/ext2fs/bmap.c | |||
@@ -0,0 +1,264 @@ | |||
1 | /* vi: set sw=4 ts=4: */ | ||
2 | /* | ||
3 | * bmap.c --- logical to physical block mapping | ||
4 | * | ||
5 | * Copyright (C) 1997 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 | |||
19 | #include "ext2_fs.h" | ||
20 | #include "ext2fs.h" | ||
21 | |||
22 | extern errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, | ||
23 | struct ext2_inode *inode, | ||
24 | char *block_buf, int bmap_flags, | ||
25 | blk_t block, blk_t *phys_blk); | ||
26 | |||
27 | #define inode_bmap(inode, nr) ((inode)->i_block[(nr)]) | ||
28 | |||
29 | static errcode_t block_ind_bmap(ext2_filsys fs, int flags, | ||
30 | blk_t ind, char *block_buf, | ||
31 | int *blocks_alloc, | ||
32 | blk_t nr, blk_t *ret_blk) | ||
33 | { | ||
34 | errcode_t retval; | ||
35 | blk_t b; | ||
36 | |||
37 | if (!ind) { | ||
38 | if (flags & BMAP_SET) | ||
39 | return EXT2_ET_SET_BMAP_NO_IND; | ||
40 | *ret_blk = 0; | ||
41 | return 0; | ||
42 | } | ||
43 | retval = io_channel_read_blk(fs->io, ind, 1, block_buf); | ||
44 | if (retval) | ||
45 | return retval; | ||
46 | |||
47 | if (flags & BMAP_SET) { | ||
48 | b = *ret_blk; | ||
49 | #if BB_BIG_ENDIAN | ||
50 | if ((fs->flags & EXT2_FLAG_SWAP_BYTES) || | ||
51 | (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)) | ||
52 | b = ext2fs_swab32(b); | ||
53 | #endif | ||
54 | ((blk_t *) block_buf)[nr] = b; | ||
55 | return io_channel_write_blk(fs->io, ind, 1, block_buf); | ||
56 | } | ||
57 | |||
58 | b = ((blk_t *) block_buf)[nr]; | ||
59 | |||
60 | #if BB_BIG_ENDIAN | ||
61 | if ((fs->flags & EXT2_FLAG_SWAP_BYTES) || | ||
62 | (fs->flags & EXT2_FLAG_SWAP_BYTES_READ)) | ||
63 | b = ext2fs_swab32(b); | ||
64 | #endif | ||
65 | |||
66 | if (!b && (flags & BMAP_ALLOC)) { | ||
67 | b = nr ? ((blk_t *) block_buf)[nr-1] : 0; | ||
68 | retval = ext2fs_alloc_block(fs, b, | ||
69 | block_buf + fs->blocksize, &b); | ||
70 | if (retval) | ||
71 | return retval; | ||
72 | |||
73 | #if BB_BIG_ENDIAN | ||
74 | if ((fs->flags & EXT2_FLAG_SWAP_BYTES) || | ||
75 | (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)) | ||
76 | ((blk_t *) block_buf)[nr] = ext2fs_swab32(b); | ||
77 | else | ||
78 | #endif | ||
79 | ((blk_t *) block_buf)[nr] = b; | ||
80 | |||
81 | retval = io_channel_write_blk(fs->io, ind, 1, block_buf); | ||
82 | if (retval) | ||
83 | return retval; | ||
84 | |||
85 | (*blocks_alloc)++; | ||
86 | } | ||
87 | |||
88 | *ret_blk = b; | ||
89 | return 0; | ||
90 | } | ||
91 | |||
92 | static errcode_t block_dind_bmap(ext2_filsys fs, int flags, | ||
93 | blk_t dind, char *block_buf, | ||
94 | int *blocks_alloc, | ||
95 | blk_t nr, blk_t *ret_blk) | ||
96 | { | ||
97 | blk_t b; | ||
98 | errcode_t retval; | ||
99 | blk_t addr_per_block; | ||
100 | |||
101 | addr_per_block = (blk_t) fs->blocksize >> 2; | ||
102 | |||
103 | retval = block_ind_bmap(fs, flags & ~BMAP_SET, dind, block_buf, | ||
104 | blocks_alloc, nr / addr_per_block, &b); | ||
105 | if (retval) | ||
106 | return retval; | ||
107 | retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc, | ||
108 | nr % addr_per_block, ret_blk); | ||
109 | return retval; | ||
110 | } | ||
111 | |||
112 | static errcode_t block_tind_bmap(ext2_filsys fs, int flags, | ||
113 | blk_t tind, char *block_buf, | ||
114 | int *blocks_alloc, | ||
115 | blk_t nr, blk_t *ret_blk) | ||
116 | { | ||
117 | blk_t b; | ||
118 | errcode_t retval; | ||
119 | blk_t addr_per_block; | ||
120 | |||
121 | addr_per_block = (blk_t) fs->blocksize >> 2; | ||
122 | |||
123 | retval = block_dind_bmap(fs, flags & ~BMAP_SET, tind, block_buf, | ||
124 | blocks_alloc, nr / addr_per_block, &b); | ||
125 | if (retval) | ||
126 | return retval; | ||
127 | retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc, | ||
128 | nr % addr_per_block, ret_blk); | ||
129 | return retval; | ||
130 | } | ||
131 | |||
132 | errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode, | ||
133 | char *block_buf, int bmap_flags, blk_t block, | ||
134 | blk_t *phys_blk) | ||
135 | { | ||
136 | struct ext2_inode inode_buf; | ||
137 | blk_t addr_per_block; | ||
138 | blk_t b; | ||
139 | char *buf = 0; | ||
140 | errcode_t retval = 0; | ||
141 | int blocks_alloc = 0, inode_dirty = 0; | ||
142 | |||
143 | if (!(bmap_flags & BMAP_SET)) | ||
144 | *phys_blk = 0; | ||
145 | |||
146 | /* Read inode structure if necessary */ | ||
147 | if (!inode) { | ||
148 | retval = ext2fs_read_inode(fs, ino, &inode_buf); | ||
149 | if (retval) | ||
150 | return retval; | ||
151 | inode = &inode_buf; | ||
152 | } | ||
153 | addr_per_block = (blk_t) fs->blocksize >> 2; | ||
154 | |||
155 | if (!block_buf) { | ||
156 | retval = ext2fs_get_mem(fs->blocksize * 2, &buf); | ||
157 | if (retval) | ||
158 | return retval; | ||
159 | block_buf = buf; | ||
160 | } | ||
161 | |||
162 | if (block < EXT2_NDIR_BLOCKS) { | ||
163 | if (bmap_flags & BMAP_SET) { | ||
164 | b = *phys_blk; | ||
165 | #if BB_BIG_ENDIAN | ||
166 | if ((fs->flags & EXT2_FLAG_SWAP_BYTES) || | ||
167 | (fs->flags & EXT2_FLAG_SWAP_BYTES_READ)) | ||
168 | b = ext2fs_swab32(b); | ||
169 | #endif | ||
170 | inode_bmap(inode, block) = b; | ||
171 | inode_dirty++; | ||
172 | goto done; | ||
173 | } | ||
174 | |||
175 | *phys_blk = inode_bmap(inode, block); | ||
176 | b = block ? inode_bmap(inode, block-1) : 0; | ||
177 | |||
178 | if ((*phys_blk == 0) && (bmap_flags & BMAP_ALLOC)) { | ||
179 | retval = ext2fs_alloc_block(fs, b, block_buf, &b); | ||
180 | if (retval) | ||
181 | goto done; | ||
182 | inode_bmap(inode, block) = b; | ||
183 | blocks_alloc++; | ||
184 | *phys_blk = b; | ||
185 | } | ||
186 | goto done; | ||
187 | } | ||
188 | |||
189 | /* Indirect block */ | ||
190 | block -= EXT2_NDIR_BLOCKS; | ||
191 | if (block < addr_per_block) { | ||
192 | b = inode_bmap(inode, EXT2_IND_BLOCK); | ||
193 | if (!b) { | ||
194 | if (!(bmap_flags & BMAP_ALLOC)) { | ||
195 | if (bmap_flags & BMAP_SET) | ||
196 | retval = EXT2_ET_SET_BMAP_NO_IND; | ||
197 | goto done; | ||
198 | } | ||
199 | |||
200 | b = inode_bmap(inode, EXT2_IND_BLOCK-1); | ||
201 | retval = ext2fs_alloc_block(fs, b, block_buf, &b); | ||
202 | if (retval) | ||
203 | goto done; | ||
204 | inode_bmap(inode, EXT2_IND_BLOCK) = b; | ||
205 | blocks_alloc++; | ||
206 | } | ||
207 | retval = block_ind_bmap(fs, bmap_flags, b, block_buf, | ||
208 | &blocks_alloc, block, phys_blk); | ||
209 | goto done; | ||
210 | } | ||
211 | |||
212 | /* Doubly indirect block */ | ||
213 | block -= addr_per_block; | ||
214 | if (block < addr_per_block * addr_per_block) { | ||
215 | b = inode_bmap(inode, EXT2_DIND_BLOCK); | ||
216 | if (!b) { | ||
217 | if (!(bmap_flags & BMAP_ALLOC)) { | ||
218 | if (bmap_flags & BMAP_SET) | ||
219 | retval = EXT2_ET_SET_BMAP_NO_IND; | ||
220 | goto done; | ||
221 | } | ||
222 | |||
223 | b = inode_bmap(inode, EXT2_IND_BLOCK); | ||
224 | retval = ext2fs_alloc_block(fs, b, block_buf, &b); | ||
225 | if (retval) | ||
226 | goto done; | ||
227 | inode_bmap(inode, EXT2_DIND_BLOCK) = b; | ||
228 | blocks_alloc++; | ||
229 | } | ||
230 | retval = block_dind_bmap(fs, bmap_flags, b, block_buf, | ||
231 | &blocks_alloc, block, phys_blk); | ||
232 | goto done; | ||
233 | } | ||
234 | |||
235 | /* Triply indirect block */ | ||
236 | block -= addr_per_block * addr_per_block; | ||
237 | b = inode_bmap(inode, EXT2_TIND_BLOCK); | ||
238 | if (!b) { | ||
239 | if (!(bmap_flags & BMAP_ALLOC)) { | ||
240 | if (bmap_flags & BMAP_SET) | ||
241 | retval = EXT2_ET_SET_BMAP_NO_IND; | ||
242 | goto done; | ||
243 | } | ||
244 | |||
245 | b = inode_bmap(inode, EXT2_DIND_BLOCK); | ||
246 | retval = ext2fs_alloc_block(fs, b, block_buf, &b); | ||
247 | if (retval) | ||
248 | goto done; | ||
249 | inode_bmap(inode, EXT2_TIND_BLOCK) = b; | ||
250 | blocks_alloc++; | ||
251 | } | ||
252 | retval = block_tind_bmap(fs, bmap_flags, b, block_buf, | ||
253 | &blocks_alloc, block, phys_blk); | ||
254 | done: | ||
255 | ext2fs_free_mem(&buf); | ||
256 | if ((retval == 0) && (blocks_alloc || inode_dirty)) { | ||
257 | inode->i_blocks += (blocks_alloc * fs->blocksize) / 512; | ||
258 | retval = ext2fs_write_inode(fs, ino, inode); | ||
259 | } | ||
260 | return retval; | ||
261 | } | ||
262 | |||
263 | |||
264 | |||