1 /*
2 * alloc.c --- allocate new inodes, blocks for ext2fs
3 *
4 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
5 *
6 * %Begin-Header%
7 * This file may be redistributed under the terms of the GNU Public
8 * License.
9 * %End-Header%
10 *
11 */
12
13 #include <stdio.h>
14 #if HAVE_UNISTD_H
15 #include <unistd.h>
16 #endif
17 #include <time.h>
18 #include <string.h>
19 #if HAVE_SYS_STAT_H
20 #include <sys/stat.h>
21 #endif
22 #if HAVE_SYS_TYPES_H
23 #include <sys/types.h>
24 #endif
25
26 #include "ext2_fs.h"
27 #include "ext2fs.h"
28
29 /*
30 * Check for uninit block bitmaps and deal with them appropriately
31 */
check_block_uninit(ext2_filsys fs,ext2fs_block_bitmap map,dgrp_t group)32 static void check_block_uninit(ext2_filsys fs, ext2fs_block_bitmap map,
33 dgrp_t group)
34 {
35 blk_t i;
36 blk_t blk, super_blk, old_desc_blk, new_desc_blk;
37 int old_desc_blocks;
38
39 if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
40 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
41 !(fs->group_desc[group].bg_flags & EXT2_BG_BLOCK_UNINIT))
42 return;
43
44 blk = (group * fs->super->s_blocks_per_group) +
45 fs->super->s_first_data_block;
46
47 ext2fs_super_and_bgd_loc(fs, group, &super_blk,
48 &old_desc_blk, &new_desc_blk, 0);
49
50 if (fs->super->s_feature_incompat &
51 EXT2_FEATURE_INCOMPAT_META_BG)
52 old_desc_blocks = fs->super->s_first_meta_bg;
53 else
54 old_desc_blocks = fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
55
56 for (i=0; i < fs->super->s_blocks_per_group; i++, blk++) {
57 if ((blk == super_blk) ||
58 (old_desc_blk && old_desc_blocks &&
59 (blk >= old_desc_blk) &&
60 (blk < old_desc_blk + old_desc_blocks)) ||
61 (new_desc_blk && (blk == new_desc_blk)) ||
62 (blk == fs->group_desc[group].bg_block_bitmap) ||
63 (blk == fs->group_desc[group].bg_inode_bitmap) ||
64 (blk >= fs->group_desc[group].bg_inode_table &&
65 (blk < fs->group_desc[group].bg_inode_table
66 + fs->inode_blocks_per_group)))
67 ext2fs_fast_mark_block_bitmap(map, blk);
68 else
69 ext2fs_fast_unmark_block_bitmap(map, blk);
70 }
71 fs->group_desc[group].bg_flags &= ~EXT2_BG_BLOCK_UNINIT;
72 ext2fs_group_desc_csum_set(fs, group);
73 }
74
75 /*
76 * Check for uninit inode bitmaps and deal with them appropriately
77 */
check_inode_uninit(ext2_filsys fs,ext2fs_inode_bitmap map,dgrp_t group)78 static void check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map,
79 dgrp_t group)
80 {
81 ext2_ino_t i, ino;
82
83 if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
84 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
85 !(fs->group_desc[group].bg_flags & EXT2_BG_INODE_UNINIT))
86 return;
87
88 ino = (group * fs->super->s_inodes_per_group) + 1;
89 for (i=0; i < fs->super->s_inodes_per_group; i++, ino++)
90 ext2fs_fast_unmark_inode_bitmap(map, ino);
91
92 fs->group_desc[group].bg_flags &= ~EXT2_BG_INODE_UNINIT;
93 check_block_uninit(fs, fs->block_map, group);
94 }
95
96 /*
97 * Right now, just search forward from the parent directory's block
98 * group to find the next free inode.
99 *
100 * Should have a special policy for directories.
101 */
ext2fs_new_inode(ext2_filsys fs,ext2_ino_t dir,int mode EXT2FS_ATTR ((unused)),ext2fs_inode_bitmap map,ext2_ino_t * ret)102 errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
103 int mode EXT2FS_ATTR((unused)),
104 ext2fs_inode_bitmap map, ext2_ino_t *ret)
105 {
106 ext2_ino_t dir_group = 0;
107 ext2_ino_t i;
108 ext2_ino_t start_inode;
109
110 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
111
112 if (!map)
113 map = fs->inode_map;
114 if (!map)
115 return EXT2_ET_NO_INODE_BITMAP;
116
117 if (dir > 0)
118 dir_group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
119
120 start_inode = (dir_group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
121 if (start_inode < EXT2_FIRST_INODE(fs->super))
122 start_inode = EXT2_FIRST_INODE(fs->super);
123 if (start_inode > fs->super->s_inodes_count)
124 return EXT2_ET_INODE_ALLOC_FAIL;
125 i = start_inode;
126
127 do {
128 if (((i - 1) % EXT2_INODES_PER_GROUP(fs->super)) == 0)
129 check_inode_uninit(fs, map, (i - 1) /
130 EXT2_INODES_PER_GROUP(fs->super));
131
132 if (!ext2fs_fast_test_inode_bitmap(map, i))
133 break;
134 i++;
135 if (i > fs->super->s_inodes_count)
136 i = EXT2_FIRST_INODE(fs->super);
137 } while (i != start_inode);
138
139 if (ext2fs_test_inode_bitmap(map, i))
140 return EXT2_ET_INODE_ALLOC_FAIL;
141 *ret = i;
142 return 0;
143 }
144
145 /*
146 * Stupid algorithm --- we now just search forward starting from the
147 * goal. Should put in a smarter one someday....
148 */
ext2fs_new_block(ext2_filsys fs,blk_t goal,ext2fs_block_bitmap map,blk_t * ret)149 errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
150 ext2fs_block_bitmap map, blk_t *ret)
151 {
152 blk_t i;
153
154 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
155
156 if (!map)
157 map = fs->block_map;
158 if (!map)
159 return EXT2_ET_NO_BLOCK_BITMAP;
160 if (!goal || (goal >= fs->super->s_blocks_count))
161 goal = fs->super->s_first_data_block;
162 i = goal;
163 check_block_uninit(fs, map,
164 (i - fs->super->s_first_data_block) /
165 EXT2_BLOCKS_PER_GROUP(fs->super));
166 do {
167 if (((i - fs->super->s_first_data_block) %
168 EXT2_BLOCKS_PER_GROUP(fs->super)) == 0)
169 check_block_uninit(fs, map,
170 (i - fs->super->s_first_data_block) /
171 EXT2_BLOCKS_PER_GROUP(fs->super));
172
173 if (!ext2fs_fast_test_block_bitmap(map, i)) {
174 *ret = i;
175 return 0;
176 }
177 i++;
178 if (i >= fs->super->s_blocks_count)
179 i = fs->super->s_first_data_block;
180 } while (i != goal);
181 return EXT2_ET_BLOCK_ALLOC_FAIL;
182 }
183
184 /*
185 * This function zeros out the allocated block, and updates all of the
186 * appropriate filesystem records.
187 */
ext2fs_alloc_block(ext2_filsys fs,blk_t goal,char * block_buf,blk_t * ret)188 errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
189 char *block_buf, blk_t *ret)
190 {
191 errcode_t retval;
192 blk_t block;
193 char *buf = 0;
194
195 if (!block_buf) {
196 retval = ext2fs_get_mem(fs->blocksize, &buf);
197 if (retval)
198 return retval;
199 block_buf = buf;
200 }
201 memset(block_buf, 0, fs->blocksize);
202
203 if (fs->get_alloc_block) {
204 blk64_t new;
205
206 retval = (fs->get_alloc_block)(fs, (blk64_t) goal, &new);
207 if (retval)
208 goto fail;
209 block = (blk_t) new;
210 } else {
211 if (!fs->block_map) {
212 retval = ext2fs_read_block_bitmap(fs);
213 if (retval)
214 goto fail;
215 }
216
217 retval = ext2fs_new_block(fs, goal, 0, &block);
218 if (retval)
219 goto fail;
220 }
221
222 retval = io_channel_write_blk(fs->io, block, 1, block_buf);
223 if (retval)
224 goto fail;
225
226 ext2fs_block_alloc_stats(fs, block, +1);
227 *ret = block;
228
229 fail:
230 if (buf)
231 ext2fs_free_mem(&buf);
232 return retval;
233 }
234
ext2fs_get_free_blocks(ext2_filsys fs,blk_t start,blk_t finish,int num,ext2fs_block_bitmap map,blk_t * ret)235 errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
236 int num, ext2fs_block_bitmap map, blk_t *ret)
237 {
238 blk_t b = start;
239
240 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
241
242 if (!map)
243 map = fs->block_map;
244 if (!map)
245 return EXT2_ET_NO_BLOCK_BITMAP;
246 if (!b)
247 b = fs->super->s_first_data_block;
248 if (!finish)
249 finish = start;
250 if (!num)
251 num = 1;
252 do {
253 if (b+num-1 > fs->super->s_blocks_count)
254 b = fs->super->s_first_data_block;
255 if (ext2fs_fast_test_block_bitmap_range(map, b, num)) {
256 *ret = b;
257 return 0;
258 }
259 b++;
260 } while (b != finish);
261 return EXT2_ET_BLOCK_ALLOC_FAIL;
262 }
263
ext2fs_set_alloc_block_callback(ext2_filsys fs,errcode_t (* func)(ext2_filsys fs,blk64_t goal,blk64_t * ret),errcode_t (** old)(ext2_filsys fs,blk64_t goal,blk64_t * ret))264 void ext2fs_set_alloc_block_callback(ext2_filsys fs,
265 errcode_t (*func)(ext2_filsys fs,
266 blk64_t goal,
267 blk64_t *ret),
268 errcode_t (**old)(ext2_filsys fs,
269 blk64_t goal,
270 blk64_t *ret))
271 {
272 if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS)
273 return;
274
275 if (old)
276 *old = fs->get_alloc_block;
277
278 fs->get_alloc_block = func;
279 }
280