source: MondoRescue/branches/stable/mindi-busybox/e2fsprogs/ext2fs/initialize.c @ 821

Last change on this file since 821 was 821, checked in by Bruno Cornec, 14 years ago

Addition of busybox 1.2.1 as a mindi-busybox new package
This should avoid delivering binary files in mindi not built there (Fedora and Debian are quite serious about that)

File size: 11.4 KB
Line 
1/*
2 * initialize.c --- initialize a filesystem handle given superblock
3 *  parameters.  Used by mke2fs when initializing a filesystem.
4 *
5 * Copyright (C) 1994, 1995, 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#if HAVE_SYS_STAT_H
21#include <sys/stat.h>
22#endif
23#if HAVE_SYS_TYPES_H
24#include <sys/types.h>
25#endif
26
27#include "ext2_fs.h"
28#include "ext2fs.h"
29
30#if defined(__linux__)    &&    defined(EXT2_OS_LINUX)
31#define CREATOR_OS EXT2_OS_LINUX
32#else
33#if defined(__GNU__)     && defined(EXT2_OS_HURD)
34#define CREATOR_OS EXT2_OS_HURD
35#else
36#if defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD)
37#define CREATOR_OS EXT2_OS_FREEBSD
38#else
39#if defined(LITES)     &&   defined(EXT2_OS_LITES)
40#define CREATOR_OS EXT2_OS_LITES
41#else
42#define CREATOR_OS EXT2_OS_LINUX /* by default */
43#endif /* defined(LITES) && defined(EXT2_OS_LITES) */
44#endif /* defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) */
45#endif /* defined(__GNU__)     && defined(EXT2_OS_HURD) */
46#endif /* defined(__linux__)   && defined(EXT2_OS_LINUX) */
47
48/*
49 * Note we override the kernel include file's idea of what the default
50 * check interval (never) should be.  It's a good idea to check at
51 * least *occasionally*, specially since servers will never rarely get
52 * to reboot, since Linux is so robust these days.  :-)
53 *
54 * 180 days (six months) seems like a good value.
55 */
56#ifdef EXT2_DFL_CHECKINTERVAL
57#undef EXT2_DFL_CHECKINTERVAL
58#endif
59#define EXT2_DFL_CHECKINTERVAL (86400L * 180L)
60
61/*
62 * Calculate the number of GDT blocks to reserve for online filesystem growth.
63 * The absolute maximum number of GDT blocks we can reserve is determined by
64 * the number of block pointers that can fit into a single block.
65 */
66static int calc_reserved_gdt_blocks(ext2_filsys fs)
67{
68    struct ext2_super_block *sb = fs->super;
69    unsigned long bpg = sb->s_blocks_per_group;
70    unsigned int gdpb = fs->blocksize / sizeof(struct ext2_group_desc);
71    unsigned long max_blocks = 0xffffffff;
72    unsigned long rsv_groups;
73    int rsv_gdb;
74
75    /* We set it at 1024x the current filesystem size, or
76     * the upper block count limit (2^32), whichever is lower.
77     */
78    if (sb->s_blocks_count < max_blocks / 1024)
79        max_blocks = sb->s_blocks_count * 1024;
80    rsv_groups = (max_blocks - sb->s_first_data_block + bpg - 1) / bpg;
81    rsv_gdb = (rsv_groups + gdpb - 1) / gdpb - fs->desc_blocks;
82    if (rsv_gdb > EXT2_ADDR_PER_BLOCK(sb))
83        rsv_gdb = EXT2_ADDR_PER_BLOCK(sb);
84#ifdef RES_GDT_DEBUG
85    printf("max_blocks %lu, rsv_groups = %lu, rsv_gdb = %lu\n",
86           max_blocks, rsv_groups, rsv_gdb);
87#endif
88
89    return rsv_gdb;
90}
91
92errcode_t ext2fs_initialize(const char *name, int flags,
93                struct ext2_super_block *param,
94                io_manager manager, ext2_filsys *ret_fs)
95{
96    ext2_filsys fs;
97    errcode_t   retval;
98    struct ext2_super_block *super;
99    int     frags_per_block;
100    unsigned int    rem;
101    unsigned int    overhead = 0;
102    blk_t       group_block;
103    unsigned int    ipg;
104    dgrp_t      i;
105    blk_t       numblocks;
106    int     rsv_gdt;
107    char        *buf;
108
109    if (!param || !param->s_blocks_count)
110        return EXT2_ET_INVALID_ARGUMENT;
111
112    retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
113    if (retval)
114        return retval;
115
116    memset(fs, 0, sizeof(struct struct_ext2_filsys));
117    fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
118    fs->flags = flags | EXT2_FLAG_RW;
119    fs->umask = 022;
120#ifdef WORDS_BIGENDIAN
121    fs->flags |= EXT2_FLAG_SWAP_BYTES;
122#endif
123    retval = manager->open(name, IO_FLAG_RW, &fs->io);
124    if (retval)
125        goto cleanup;
126    fs->image_io = fs->io;
127    fs->io->app_data = fs;
128    retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
129    if (retval)
130        goto cleanup;
131
132    strcpy(fs->device_name, name);
133    retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super);
134    if (retval)
135        goto cleanup;
136    fs->super = super;
137
138    memset(super, 0, SUPERBLOCK_SIZE);
139
140#define set_field(field, default) (super->field = param->field ? \
141                   param->field : (default))
142
143    super->s_magic = EXT2_SUPER_MAGIC;
144    super->s_state = EXT2_VALID_FS;
145
146    set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */
147    set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
148    set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
149    set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
150    set_field(s_errors, EXT2_ERRORS_DEFAULT);
151    set_field(s_feature_compat, 0);
152    set_field(s_feature_incompat, 0);
153    set_field(s_feature_ro_compat, 0);
154    set_field(s_first_meta_bg, 0);
155    if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
156        retval = EXT2_ET_UNSUPP_FEATURE;
157        goto cleanup;
158    }
159    if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
160        retval = EXT2_ET_RO_UNSUPP_FEATURE;
161        goto cleanup;
162    }
163
164    set_field(s_rev_level, EXT2_GOOD_OLD_REV);
165    if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
166        set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
167        set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
168    }
169
170    set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
171    super->s_mkfs_time = super->s_lastcheck = time(NULL);
172
173    super->s_creator_os = CREATOR_OS;
174
175    fs->blocksize = EXT2_BLOCK_SIZE(super);
176    fs->fragsize = EXT2_FRAG_SIZE(super);
177    frags_per_block = fs->blocksize / fs->fragsize;
178
179    /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
180    set_field(s_blocks_per_group, fs->blocksize * 8);
181    if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
182        super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
183    super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;
184
185    super->s_blocks_count = param->s_blocks_count;
186    super->s_r_blocks_count = param->s_r_blocks_count;
187    if (super->s_r_blocks_count >= param->s_blocks_count) {
188        retval = EXT2_ET_INVALID_ARGUMENT;
189        goto cleanup;
190    }
191
192    /*
193     * If we're creating an external journal device, we don't need
194     * to bother with the rest.
195     */
196    if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
197        fs->group_desc_count = 0;
198        ext2fs_mark_super_dirty(fs);
199        *ret_fs = fs;
200        return 0;
201    }
202
203retry:
204    fs->group_desc_count = (super->s_blocks_count -
205                super->s_first_data_block +
206                EXT2_BLOCKS_PER_GROUP(super) - 1)
207        / EXT2_BLOCKS_PER_GROUP(super);
208    if (fs->group_desc_count == 0) {
209        retval = EXT2_ET_TOOSMALL;
210        goto cleanup;
211    }
212    fs->desc_blocks = (fs->group_desc_count +
213               EXT2_DESC_PER_BLOCK(super) - 1)
214        / EXT2_DESC_PER_BLOCK(super);
215
216    i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
217    set_field(s_inodes_count, super->s_blocks_count / i);
218
219    /*
220     * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
221     * that we have enough inodes for the filesystem(!)
222     */
223    if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
224        super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
225
226    /*
227     * There should be at least as many inodes as the user
228     * requested.  Figure out how many inodes per group that
229     * should be.  But make sure that we don't allocate more than
230     * one bitmap's worth of inodes each group.
231     */
232    ipg = (super->s_inodes_count + fs->group_desc_count - 1) /
233        fs->group_desc_count;
234    if (ipg > fs->blocksize * 8) {
235        if (super->s_blocks_per_group >= 256) {
236            /* Try again with slightly different parameters */
237            super->s_blocks_per_group -= 8;
238            super->s_blocks_count = param->s_blocks_count;
239            super->s_frags_per_group = super->s_blocks_per_group *
240                frags_per_block;
241            goto retry;
242        } else
243            return EXT2_ET_TOO_MANY_INODES;
244    }
245
246    if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super))
247        ipg = EXT2_MAX_INODES_PER_GROUP(super);
248
249    super->s_inodes_per_group = ipg;
250    if (super->s_inodes_count > ipg * fs->group_desc_count)
251        super->s_inodes_count = ipg * fs->group_desc_count;
252
253    /*
254     * Make sure the number of inodes per group completely fills
255     * the inode table blocks in the descriptor.  If not, add some
256     * additional inodes/group.  Waste not, want not...
257     */
258    fs->inode_blocks_per_group = (((super->s_inodes_per_group *
259                    EXT2_INODE_SIZE(super)) +
260                       EXT2_BLOCK_SIZE(super) - 1) /
261                      EXT2_BLOCK_SIZE(super));
262    super->s_inodes_per_group = ((fs->inode_blocks_per_group *
263                      EXT2_BLOCK_SIZE(super)) /
264                     EXT2_INODE_SIZE(super));
265    /*
266     * Finally, make sure the number of inodes per group is a
267     * multiple of 8.  This is needed to simplify the bitmap
268     * splicing code.
269     */
270    super->s_inodes_per_group &= ~7;
271    fs->inode_blocks_per_group = (((super->s_inodes_per_group *
272                    EXT2_INODE_SIZE(super)) +
273                       EXT2_BLOCK_SIZE(super) - 1) /
274                      EXT2_BLOCK_SIZE(super));
275
276    /*
277     * adjust inode count to reflect the adjusted inodes_per_group
278     */
279    super->s_inodes_count = super->s_inodes_per_group *
280        fs->group_desc_count;
281    super->s_free_inodes_count = super->s_inodes_count;
282
283    /*
284     * check the number of reserved group descriptor table blocks
285     */
286    if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE)
287        rsv_gdt = calc_reserved_gdt_blocks(fs);
288    else
289        rsv_gdt = 0;
290    set_field(s_reserved_gdt_blocks, rsv_gdt);
291    if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) {
292        retval = EXT2_ET_RES_GDT_BLOCKS;
293        goto cleanup;
294    }
295
296    /*
297     * Overhead is the number of bookkeeping blocks per group.  It
298     * includes the superblock backup, the group descriptor
299     * backups, the inode bitmap, the block bitmap, and the inode
300     * table.
301     */
302
303    overhead = (int) (2 + fs->inode_blocks_per_group);
304
305    if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1))
306        overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks;
307
308    /* This can only happen if the user requested too many inodes */
309    if (overhead > super->s_blocks_per_group)
310        return EXT2_ET_TOO_MANY_INODES;
311
312    /*
313     * See if the last group is big enough to support the
314     * necessary data structures.  If not, we need to get rid of
315     * it.
316     */
317    rem = ((super->s_blocks_count - super->s_first_data_block) %
318           super->s_blocks_per_group);
319    if ((fs->group_desc_count == 1) && rem && (rem < overhead))
320        return EXT2_ET_TOOSMALL;
321    if (rem && (rem < overhead+50)) {
322        super->s_blocks_count -= rem;
323        goto retry;
324    }
325
326    /*
327     * At this point we know how big the filesystem will be.  So
328     * we can do any and all allocations that depend on the block
329     * count.
330     */
331
332    retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
333    if (retval)
334        goto cleanup;
335
336    sprintf(buf, "block bitmap for %s", fs->device_name);
337    retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
338    if (retval)
339        goto cleanup;
340
341    sprintf(buf, "inode bitmap for %s", fs->device_name);
342    retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
343    if (retval)
344        goto cleanup;
345
346    ext2fs_free_mem(&buf);
347
348    retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize,
349                &fs->group_desc);
350    if (retval)
351        goto cleanup;
352
353    memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
354
355    /*
356     * Reserve the superblock and group descriptors for each
357     * group, and fill in the correct group statistics for group.
358     * Note that although the block bitmap, inode bitmap, and
359     * inode table have not been allocated (and in fact won't be
360     * by this routine), they are accounted for nevertheless.
361     */
362    group_block = super->s_first_data_block;
363    super->s_free_blocks_count = 0;
364    for (i = 0; i < fs->group_desc_count; i++) {
365        numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
366
367        super->s_free_blocks_count += numblocks;
368        fs->group_desc[i].bg_free_blocks_count = numblocks;
369        fs->group_desc[i].bg_free_inodes_count =
370            fs->super->s_inodes_per_group;
371        fs->group_desc[i].bg_used_dirs_count = 0;
372
373        group_block += super->s_blocks_per_group;
374    }
375
376    ext2fs_mark_super_dirty(fs);
377    ext2fs_mark_bb_dirty(fs);
378    ext2fs_mark_ib_dirty(fs);
379
380    io_channel_set_blksize(fs->io, fs->blocksize);
381
382    *ret_fs = fs;
383    return 0;
384cleanup:
385    ext2fs_free(fs);
386    return retval;
387}
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