source: branches/3.2/mindi-busybox/e2fsprogs/old_e2fsprogs/ext2fs/initialize.c @ 3232

Last change on this file since 3232 was 3232, checked in by bruno, 5 years ago
  • Update mindi-busybox to 1.21.1
  • Property svn:eol-style set to native
File size: 11.5 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * initialize.c --- initialize a filesystem handle given superblock
4 *  parameters.  Used by mke2fs when initializing a filesystem.
5 *
6 * Copyright (C) 1994, 1995, 1996 Theodore Ts'o.
7 *
8 * %Begin-Header%
9 * This file may be redistributed under the terms of the GNU Public
10 * License.
11 * %End-Header%
12 */
13
14#include <stdio.h>
15#include <string.h>
16#if HAVE_UNISTD_H
17#include <unistd.h>
18#endif
19#include <fcntl.h>
20#include <time.h>
21#if HAVE_SYS_STAT_H
22#include <sys/stat.h>
23#endif
24#if HAVE_SYS_TYPES_H
25#include <sys/types.h>
26#endif
27
28#include "ext2_fs.h"
29#include "ext2fs.h"
30
31#if defined(__linux__)    &&    defined(EXT2_OS_LINUX)
32#define CREATOR_OS EXT2_OS_LINUX
33#else
34#if defined(__GNU__)     && defined(EXT2_OS_HURD)
35#define CREATOR_OS EXT2_OS_HURD
36#else
37#if defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD)
38#define CREATOR_OS EXT2_OS_FREEBSD
39#else
40#if defined(LITES)     &&   defined(EXT2_OS_LITES)
41#define CREATOR_OS EXT2_OS_LITES
42#else
43#define CREATOR_OS EXT2_OS_LINUX /* by default */
44#endif /* defined(LITES) && defined(EXT2_OS_LITES) */
45#endif /* defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) */
46#endif /* defined(__GNU__)     && defined(EXT2_OS_HURD) */
47#endif /* defined(__linux__)   && defined(EXT2_OS_LINUX) */
48
49/*
50 * Note we override the kernel include file's idea of what the default
51 * check interval (never) should be.  It's a good idea to check at
52 * least *occasionally*, specially since servers will never rarely get
53 * to reboot, since Linux is so robust these days.  :-)
54 *
55 * 180 days (six months) seems like a good value.
56 */
57#ifdef EXT2_DFL_CHECKINTERVAL
58#undef EXT2_DFL_CHECKINTERVAL
59#endif
60#define EXT2_DFL_CHECKINTERVAL (86400L * 180L)
61
62/*
63 * Calculate the number of GDT blocks to reserve for online filesystem growth.
64 * The absolute maximum number of GDT blocks we can reserve is determined by
65 * the number of block pointers that can fit into a single block.
66 */
67static int calc_reserved_gdt_blocks(ext2_filsys fs)
68{
69    struct ext2_super_block *sb = fs->super;
70    unsigned long bpg = sb->s_blocks_per_group;
71    unsigned int gdpb = fs->blocksize / sizeof(struct ext2_group_desc);
72    unsigned long max_blocks = 0xffffffff;
73    unsigned long rsv_groups;
74    int rsv_gdb;
75
76    /* We set it at 1024x the current filesystem size, or
77     * the upper block count limit (2^32), whichever is lower.
78     */
79    if (sb->s_blocks_count < max_blocks / 1024)
80        max_blocks = sb->s_blocks_count * 1024;
81    rsv_groups = (max_blocks - sb->s_first_data_block + bpg - 1) / bpg;
82    rsv_gdb = (rsv_groups + gdpb - 1) / gdpb - fs->desc_blocks;
83    if (rsv_gdb > EXT2_ADDR_PER_BLOCK(sb))
84        rsv_gdb = EXT2_ADDR_PER_BLOCK(sb);
85#ifdef RES_GDT_DEBUG
86    printf("max_blocks %lu, rsv_groups = %lu, rsv_gdb = %lu\n",
87           max_blocks, rsv_groups, rsv_gdb);
88#endif
89
90    return rsv_gdb;
91}
92
93errcode_t ext2fs_initialize(const char *name, int flags,
94                struct ext2_super_block *param,
95                io_manager manager, ext2_filsys *ret_fs)
96{
97    ext2_filsys fs;
98    errcode_t   retval;
99    struct ext2_super_block *super;
100    int     frags_per_block;
101    unsigned int    rem;
102    unsigned int    overhead = 0;
103    blk_t       group_block;
104    unsigned int    ipg;
105    dgrp_t      i;
106    blk_t       numblocks;
107    int     rsv_gdt;
108    char        *buf;
109
110    if (!param || !param->s_blocks_count)
111        return EXT2_ET_INVALID_ARGUMENT;
112
113    retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
114    if (retval)
115        return retval;
116
117    memset(fs, 0, sizeof(struct struct_ext2_filsys));
118    fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
119    fs->flags = flags | EXT2_FLAG_RW;
120    fs->umask = 022;
121#ifdef WORDS_BIGENDIAN
122    fs->flags |= EXT2_FLAG_SWAP_BYTES;
123#endif
124    retval = manager->open(name, IO_FLAG_RW, &fs->io);
125    if (retval)
126        goto cleanup;
127    fs->image_io = fs->io;
128    fs->io->app_data = fs;
129    retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
130    if (retval)
131        goto cleanup;
132
133    strcpy(fs->device_name, name);
134    retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super);
135    if (retval)
136        goto cleanup;
137    fs->super = super;
138
139    memset(super, 0, SUPERBLOCK_SIZE);
140
141#define set_field(field, default) (super->field = param->field ? \
142                   param->field : (default))
143
144    super->s_magic = EXT2_SUPER_MAGIC;
145    super->s_state = EXT2_VALID_FS;
146
147    set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */
148    set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
149    set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
150    set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
151    set_field(s_errors, EXT2_ERRORS_DEFAULT);
152    set_field(s_feature_compat, 0);
153    set_field(s_feature_incompat, 0);
154    set_field(s_feature_ro_compat, 0);
155    set_field(s_first_meta_bg, 0);
156    if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
157        retval = EXT2_ET_UNSUPP_FEATURE;
158        goto cleanup;
159    }
160    if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
161        retval = EXT2_ET_RO_UNSUPP_FEATURE;
162        goto cleanup;
163    }
164
165    set_field(s_rev_level, EXT2_GOOD_OLD_REV);
166    if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
167        set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
168        set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
169    }
170
171    set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
172    super->s_mkfs_time = super->s_lastcheck = time(NULL);
173
174    super->s_creator_os = CREATOR_OS;
175
176    fs->blocksize = EXT2_BLOCK_SIZE(super);
177    fs->fragsize = EXT2_FRAG_SIZE(super);
178    frags_per_block = fs->blocksize / fs->fragsize;
179
180    /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
181    set_field(s_blocks_per_group, fs->blocksize * 8);
182    if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
183        super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
184    super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;
185
186    super->s_blocks_count = param->s_blocks_count;
187    super->s_r_blocks_count = param->s_r_blocks_count;
188    if (super->s_r_blocks_count >= param->s_blocks_count) {
189        retval = EXT2_ET_INVALID_ARGUMENT;
190        goto cleanup;
191    }
192
193    /*
194     * If we're creating an external journal device, we don't need
195     * to bother with the rest.
196     */
197    if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
198        fs->group_desc_count = 0;
199        ext2fs_mark_super_dirty(fs);
200        *ret_fs = fs;
201        return 0;
202    }
203
204retry:
205    fs->group_desc_count = (super->s_blocks_count -
206                super->s_first_data_block +
207                EXT2_BLOCKS_PER_GROUP(super) - 1)
208        / EXT2_BLOCKS_PER_GROUP(super);
209    if (fs->group_desc_count == 0) {
210        retval = EXT2_ET_TOOSMALL;
211        goto cleanup;
212    }
213    fs->desc_blocks = (fs->group_desc_count +
214               EXT2_DESC_PER_BLOCK(super) - 1)
215        / EXT2_DESC_PER_BLOCK(super);
216
217    i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
218    set_field(s_inodes_count, super->s_blocks_count / i);
219
220    /*
221     * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
222     * that we have enough inodes for the filesystem(!)
223     */
224    if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
225        super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
226
227    /*
228     * There should be at least as many inodes as the user
229     * requested.  Figure out how many inodes per group that
230     * should be.  But make sure that we don't allocate more than
231     * one bitmap's worth of inodes each group.
232     */
233    ipg = (super->s_inodes_count + fs->group_desc_count - 1) /
234        fs->group_desc_count;
235    if (ipg > fs->blocksize * 8) {
236        if (super->s_blocks_per_group >= 256) {
237            /* Try again with slightly different parameters */
238            super->s_blocks_per_group -= 8;
239            super->s_blocks_count = param->s_blocks_count;
240            super->s_frags_per_group = super->s_blocks_per_group *
241                frags_per_block;
242            goto retry;
243        } else
244            return EXT2_ET_TOO_MANY_INODES;
245    }
246
247    if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super))
248        ipg = EXT2_MAX_INODES_PER_GROUP(super);
249
250    super->s_inodes_per_group = ipg;
251    if (super->s_inodes_count > ipg * fs->group_desc_count)
252        super->s_inodes_count = ipg * fs->group_desc_count;
253
254    /*
255     * Make sure the number of inodes per group completely fills
256     * the inode table blocks in the descriptor.  If not, add some
257     * additional inodes/group.  Waste not, want not...
258     */
259    fs->inode_blocks_per_group = (((super->s_inodes_per_group *
260                    EXT2_INODE_SIZE(super)) +
261                       EXT2_BLOCK_SIZE(super) - 1) /
262                      EXT2_BLOCK_SIZE(super));
263    super->s_inodes_per_group = ((fs->inode_blocks_per_group *
264                      EXT2_BLOCK_SIZE(super)) /
265                     EXT2_INODE_SIZE(super));
266    /*
267     * Finally, make sure the number of inodes per group is a
268     * multiple of 8.  This is needed to simplify the bitmap
269     * splicing code.
270     */
271    super->s_inodes_per_group &= ~7;
272    fs->inode_blocks_per_group = (((super->s_inodes_per_group *
273                    EXT2_INODE_SIZE(super)) +
274                       EXT2_BLOCK_SIZE(super) - 1) /
275                      EXT2_BLOCK_SIZE(super));
276
277    /*
278     * adjust inode count to reflect the adjusted inodes_per_group
279     */
280    super->s_inodes_count = super->s_inodes_per_group *
281        fs->group_desc_count;
282    super->s_free_inodes_count = super->s_inodes_count;
283
284    /*
285     * check the number of reserved group descriptor table blocks
286     */
287    if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INO)
288        rsv_gdt = calc_reserved_gdt_blocks(fs);
289    else
290        rsv_gdt = 0;
291    set_field(s_reserved_gdt_blocks, rsv_gdt);
292    if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) {
293        retval = EXT2_ET_RES_GDT_BLOCKS;
294        goto cleanup;
295    }
296
297    /*
298     * Overhead is the number of bookkeeping blocks per group.  It
299     * includes the superblock backup, the group descriptor
300     * backups, the inode bitmap, the block bitmap, and the inode
301     * table.
302     */
303
304    overhead = (int) (2 + fs->inode_blocks_per_group);
305
306    if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1))
307        overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks;
308
309    /* This can only happen if the user requested too many inodes */
310    if (overhead > super->s_blocks_per_group)
311        return EXT2_ET_TOO_MANY_INODES;
312
313    /*
314     * See if the last group is big enough to support the
315     * necessary data structures.  If not, we need to get rid of
316     * it.
317     */
318    rem = ((super->s_blocks_count - super->s_first_data_block) %
319           super->s_blocks_per_group);
320    if ((fs->group_desc_count == 1) && rem && (rem < overhead))
321        return EXT2_ET_TOOSMALL;
322    if (rem && (rem < overhead+50)) {
323        super->s_blocks_count -= rem;
324        goto retry;
325    }
326
327    /*
328     * At this point we know how big the filesystem will be.  So
329     * we can do any and all allocations that depend on the block
330     * count.
331     */
332
333    retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
334    if (retval)
335        goto cleanup;
336
337    sprintf(buf, "block bitmap for %s", fs->device_name);
338    retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
339    if (retval)
340        goto cleanup;
341
342    sprintf(buf, "inode bitmap for %s", fs->device_name);
343    retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
344    if (retval)
345        goto cleanup;
346
347    ext2fs_free_mem(&buf);
348
349    retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize,
350                &fs->group_desc);
351    if (retval)
352        goto cleanup;
353
354    memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
355
356    /*
357     * Reserve the superblock and group descriptors for each
358     * group, and fill in the correct group statistics for group.
359     * Note that although the block bitmap, inode bitmap, and
360     * inode table have not been allocated (and in fact won't be
361     * by this routine), they are accounted for nevertheless.
362     */
363    group_block = super->s_first_data_block;
364    super->s_free_blocks_count = 0;
365    for (i = 0; i < fs->group_desc_count; i++) {
366        numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
367
368        super->s_free_blocks_count += numblocks;
369        fs->group_desc[i].bg_free_blocks_count = numblocks;
370        fs->group_desc[i].bg_free_inodes_count =
371            fs->super->s_inodes_per_group;
372        fs->group_desc[i].bg_used_dirs_count = 0;
373
374        group_block += super->s_blocks_per_group;
375    }
376
377    ext2fs_mark_super_dirty(fs);
378    ext2fs_mark_bb_dirty(fs);
379    ext2fs_mark_ib_dirty(fs);
380
381    io_channel_set_blksize(fs->io, fs->blocksize);
382
383    *ret_fs = fs;
384    return 0;
385cleanup:
386    ext2fs_free(fs);
387    return retval;
388}
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