initialize.c revision e5b38a5fafe4807b54d90a2e70bddf4b41b1695b 
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#if EXT2_FLAT_INCLUDES
28#include "ext2_fs.h"
29#else
30#include <linux/ext2_fs.h>
31#endif
32
33#include "ext2fs.h"
34
35#if  defined(__linux__)    &&	defined(EXT2_OS_LINUX)
36#define CREATOR_OS EXT2_OS_LINUX
37#elif defined(__GNU__)     &&	defined(EXT2_OS_HURD)
38#define CREATOR_OS EXT2_OS_HURD
39#elif defined(__FreeBSD__) &&	defined(EXT2_OS_FREEBSD)
40#define CREATOR_OS EXT2_OS_FREEBSD
41#elif defined(LITES) 	   &&	defined(EXT2_OS_LITES)
42#define CREATOR_OS EXT2_OS_LITES
43#else
44#define CREATOR_OS EXT2_OS_LINUX /* by default */
45#endif
46
47/*
48 * Note we override the kernel include file's idea of what the default
49 * check interval (never) should be.  It's a good idea to check at
50 * least *occasionally*, specially since servers will never rarely get
51 * to reboot, since Linux is so robust these days.  :-)
52 *
53 * 180 days (six months) seems like a good value.
54 */
55#ifdef EXT2_DFL_CHECKINTERVAL
56#undef EXT2_DFL_CHECKINTERVAL
57#endif
58#define EXT2_DFL_CHECKINTERVAL (86400L * 180L)
59
60errcode_t ext2fs_initialize(const char *name, int flags,
61			    struct ext2_super_block *param,
62			    io_manager manager, ext2_filsys *ret_fs)
63{
64	ext2_filsys	fs;
65	errcode_t	retval;
66	struct ext2_super_block *super;
67	int		frags_per_block;
68	int		rem;
69	int		overhead = 0;
70	blk_t		group_block;
71	int		i, j;
72	blk_t		numblocks;
73	char		*buf;
74
75	if (!param || !param->s_blocks_count)
76		return EXT2_ET_INVALID_ARGUMENT;
77
78	retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys),
79				(void **) &fs);
80	if (retval)
81		return retval;
82
83	memset(fs, 0, sizeof(struct struct_ext2_filsys));
84	fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
85	fs->flags = flags | EXT2_FLAG_RW | ext2fs_native_flag();
86	retval = manager->open(name, IO_FLAG_RW, &fs->io);
87	if (retval)
88		goto cleanup;
89	fs->io->app_data = fs;
90	retval = ext2fs_get_mem(strlen(name)+1, (void **) &fs->device_name);
91	if (retval)
92		goto cleanup;
93
94	strcpy(fs->device_name, name);
95	retval = ext2fs_get_mem(SUPERBLOCK_SIZE, (void **) &super);
96	if (retval)
97		goto cleanup;
98	fs->super = super;
99
100	memset(super, 0, SUPERBLOCK_SIZE);
101
102#define set_field(field, default) (super->field = param->field ? \
103				   param->field : (default))
104
105	super->s_magic = EXT2_SUPER_MAGIC;
106	super->s_state = EXT2_VALID_FS;
107
108	set_field(s_log_block_size, 0);	/* default blocksize: 1024 bytes */
109	set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
110	set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
111	set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
112	set_field(s_errors, EXT2_ERRORS_DEFAULT);
113	set_field(s_feature_compat, 0);
114	set_field(s_feature_incompat, 0);
115	set_field(s_feature_ro_compat, 0);
116	if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP)
117		return EXT2_ET_UNSUPP_FEATURE;
118	if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)
119		return EXT2_ET_RO_UNSUPP_FEATURE;
120
121	set_field(s_rev_level, EXT2_GOOD_OLD_REV);
122	if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
123		set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
124		set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
125	}
126
127	set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
128	super->s_lastcheck = time(NULL);
129
130	super->s_creator_os = CREATOR_OS;
131
132	fs->blocksize = EXT2_BLOCK_SIZE(super);
133	fs->fragsize = EXT2_FRAG_SIZE(super);
134	frags_per_block = fs->blocksize / fs->fragsize;
135
136	/* default: (fs->blocksize*8) blocks/group */
137	set_field(s_blocks_per_group, fs->blocksize*8);
138	super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;
139
140	super->s_blocks_count = param->s_blocks_count;
141	super->s_r_blocks_count = param->s_r_blocks_count;
142	if (super->s_r_blocks_count >= param->s_blocks_count) {
143		retval = EXT2_ET_INVALID_ARGUMENT;
144		goto cleanup;
145	}
146
147retry:
148	fs->group_desc_count = (super->s_blocks_count -
149				super->s_first_data_block +
150				EXT2_BLOCKS_PER_GROUP(super) - 1)
151		/ EXT2_BLOCKS_PER_GROUP(super);
152	if (fs->group_desc_count == 0)
153		return EXT2_ET_TOOSMALL;
154	fs->desc_blocks = (fs->group_desc_count +
155			   EXT2_DESC_PER_BLOCK(super) - 1)
156		/ EXT2_DESC_PER_BLOCK(super);
157
158	/* n.b., fs->blocksize is <= 4096 */
159	set_field(s_inodes_count, super->s_blocks_count/(4096/fs->blocksize));
160
161	/*
162	 * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
163	 * that we have enough inodes for the filesystem(!)
164	 */
165	if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
166		super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
167
168	/*
169	 * There should be at least as many inodes as the user
170	 * requested.  Figure out how many inodes per group that
171	 * should be.  But make sure that we don't allocate more than
172	 * one bitmap's worth of inodes
173	 */
174	super->s_inodes_per_group = (super->s_inodes_count +
175				     fs->group_desc_count - 1) /
176					     fs->group_desc_count;
177	if (super->s_inodes_per_group > fs->blocksize*8)
178		super->s_inodes_per_group = fs->blocksize*8;
179
180	/*
181	 * Make sure the number of inodes per group completely fills
182	 * the inode table blocks in the descriptor.  If not, add some
183	 * additional inodes/group.  Waste not, want not...
184	 */
185	fs->inode_blocks_per_group = (((super->s_inodes_per_group *
186					EXT2_INODE_SIZE(super)) +
187				       EXT2_BLOCK_SIZE(super) - 1) /
188				      EXT2_BLOCK_SIZE(super));
189	super->s_inodes_per_group = ((fs->inode_blocks_per_group *
190				      EXT2_BLOCK_SIZE(super)) /
191				     EXT2_INODE_SIZE(super));
192	/*
193	 * Finally, make sure the number of inodes per group is a
194	 * multiple of 8.  This is needed to simplify the bitmap
195	 * splicing code.
196	 */
197	super->s_inodes_per_group &= ~7;
198	fs->inode_blocks_per_group = (((super->s_inodes_per_group *
199					EXT2_INODE_SIZE(super)) +
200				       EXT2_BLOCK_SIZE(super) - 1) /
201				      EXT2_BLOCK_SIZE(super));
202
203	/*
204	 * adjust inode count to reflect the adjusted inodes_per_group
205	 */
206	super->s_inodes_count = super->s_inodes_per_group *
207		fs->group_desc_count;
208	super->s_free_inodes_count = super->s_inodes_count;
209
210	/*
211	 * Overhead is the number of bookkeeping blocks per group.  It
212	 * includes the superblock backup, the group descriptor
213	 * backups, the inode bitmap, the block bitmap, and the inode
214	 * table.
215	 *
216	 * XXX Not all block groups need the descriptor blocks, but
217	 * being clever is tricky...
218	 */
219	overhead = (int) (3 + fs->desc_blocks + fs->inode_blocks_per_group);
220
221	/*
222	 * See if the last group is big enough to support the
223	 * necessary data structures.  If not, we need to get rid of
224	 * it.
225	 */
226	rem = (int) ((super->s_blocks_count - super->s_first_data_block) %
227		     super->s_blocks_per_group);
228	if ((fs->group_desc_count == 1) && rem && (rem < overhead))
229		return EXT2_ET_TOOSMALL;
230	if (rem && (rem < overhead+50)) {
231		super->s_blocks_count -= rem;
232		goto retry;
233	}
234
235	/*
236	 * At this point we know how big the filesystem will be.  So
237	 * we can do any and all allocations that depend on the block
238	 * count.
239	 */
240
241	retval = ext2fs_get_mem(strlen(fs->device_name) + 80,
242				(void **) &buf);
243	if (retval)
244		goto cleanup;
245
246	sprintf(buf, "block bitmap for %s", fs->device_name);
247	retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
248	if (retval)
249		goto cleanup;
250
251	sprintf(buf, "inode bitmap for %s", fs->device_name);
252	retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
253	if (retval)
254		goto cleanup;
255
256	ext2fs_free_mem((void **) &buf);
257
258	retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize,
259				(void **) &fs->group_desc);
260	if (retval)
261		goto cleanup;
262
263	memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
264
265	/*
266	 * Reserve the superblock and group descriptors for each
267	 * group, and fill in the correct group statistics for group.
268	 * Note that although the block bitmap, inode bitmap, and
269	 * inode table have not been allocated (and in fact won't be
270	 * by this routine), they are accounted for nevertheless.
271	 */
272	group_block = super->s_first_data_block;
273	super->s_free_blocks_count = 0;
274	for (i = 0; i < fs->group_desc_count; i++) {
275		if (i == fs->group_desc_count-1) {
276			numblocks = (fs->super->s_blocks_count -
277				     fs->super->s_first_data_block) %
278					     fs->super->s_blocks_per_group;
279			if (!numblocks)
280				numblocks = fs->super->s_blocks_per_group;
281		} else
282			numblocks = fs->super->s_blocks_per_group;
283
284		if (ext2fs_bg_has_super(fs, i)) {
285			for (j=0; j < fs->desc_blocks+1; j++)
286				ext2fs_mark_block_bitmap(fs->block_map,
287							 group_block + j);
288			numblocks -= 1 + fs->desc_blocks;
289		}
290
291		numblocks -= 2 + fs->inode_blocks_per_group;
292
293		super->s_free_blocks_count += numblocks;
294		fs->group_desc[i].bg_free_blocks_count = numblocks;
295		fs->group_desc[i].bg_free_inodes_count =
296			fs->super->s_inodes_per_group;
297		fs->group_desc[i].bg_used_dirs_count = 0;
298
299		group_block += super->s_blocks_per_group;
300	}
301
302	ext2fs_mark_super_dirty(fs);
303	ext2fs_mark_bb_dirty(fs);
304	ext2fs_mark_ib_dirty(fs);
305
306	io_channel_set_blksize(fs->io, fs->blocksize);
307
308	*ret_fs = fs;
309	return 0;
310cleanup:
311	ext2fs_free(fs);
312	return retval;
313}
314
315
316
317