initialize.c revision 9d2aefb3bc0a48b1540d06e1983aa96c56d39e17 
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#elif defined(__GNU__)     &&	defined(EXT2_OS_HURD)
33#define CREATOR_OS EXT2_OS_HURD
34#elif defined(__FreeBSD__) &&	defined(EXT2_OS_FREEBSD)
35#define CREATOR_OS EXT2_OS_FREEBSD
36#elif defined(LITES) 	   &&	defined(EXT2_OS_LITES)
37#define CREATOR_OS EXT2_OS_LITES
38#else
39#define CREATOR_OS EXT2_OS_LINUX /* by default */
40#endif
41
42/*
43 * Note we override the kernel include file's idea of what the default
44 * check interval (never) should be.  It's a good idea to check at
45 * least *occasionally*, specially since servers will never rarely get
46 * to reboot, since Linux is so robust these days.  :-)
47 *
48 * 180 days (six months) seems like a good value.
49 */
50#ifdef EXT2_DFL_CHECKINTERVAL
51#undef EXT2_DFL_CHECKINTERVAL
52#endif
53#define EXT2_DFL_CHECKINTERVAL (86400L * 180L)
54
55errcode_t ext2fs_initialize(const char *name, int flags,
56			    struct ext2_super_block *param,
57			    io_manager manager, ext2_filsys *ret_fs)
58{
59	ext2_filsys	fs;
60	errcode_t	retval;
61	struct ext2_super_block *super;
62	int		frags_per_block;
63	int		rem;
64	int		overhead = 0;
65	blk_t		group_block;
66	int		ipg;
67	int		i, j;
68	blk_t		numblocks;
69	char		*buf;
70	int		meta_bg_size, meta_bg, has_super;
71
72	if (!param || !param->s_blocks_count)
73		return EXT2_ET_INVALID_ARGUMENT;
74
75	retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys),
76				(void **) &fs);
77	if (retval)
78		return retval;
79
80	memset(fs, 0, sizeof(struct struct_ext2_filsys));
81	fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
82	fs->flags = flags | EXT2_FLAG_RW;
83	fs->umask = 022;
84#ifdef WORDS_BIGENDIAN
85	fs->flags |= EXT2_FLAG_SWAP_BYTES;
86#endif
87	retval = manager->open(name, IO_FLAG_RW, &fs->io);
88	if (retval)
89		goto cleanup;
90	fs->io->app_data = fs;
91	retval = ext2fs_get_mem(strlen(name)+1, (void **) &fs->device_name);
92	if (retval)
93		goto cleanup;
94
95	strcpy(fs->device_name, name);
96	retval = ext2fs_get_mem(SUPERBLOCK_SIZE, (void **) &super);
97	if (retval)
98		goto cleanup;
99	fs->super = super;
100
101	memset(super, 0, SUPERBLOCK_SIZE);
102
103#define set_field(field, default) (super->field = param->field ? \
104				   param->field : (default))
105
106	super->s_magic = EXT2_SUPER_MAGIC;
107	super->s_state = EXT2_VALID_FS;
108
109	set_field(s_log_block_size, 0);	/* default blocksize: 1024 bytes */
110	set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
111	set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
112	set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
113	set_field(s_errors, EXT2_ERRORS_DEFAULT);
114	set_field(s_feature_compat, 0);
115	set_field(s_feature_incompat, 0);
116	set_field(s_feature_ro_compat, 0);
117	set_field(s_first_meta_bg, 0);
118	if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP)
119		return EXT2_ET_UNSUPP_FEATURE;
120	if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)
121		return EXT2_ET_RO_UNSUPP_FEATURE;
122
123	set_field(s_rev_level, EXT2_GOOD_OLD_REV);
124	if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
125		set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
126		set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
127	}
128
129	set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
130	super->s_mkfs_time = super->s_lastcheck = time(NULL);
131
132	super->s_creator_os = CREATOR_OS;
133
134	fs->blocksize = EXT2_BLOCK_SIZE(super);
135	fs->fragsize = EXT2_FRAG_SIZE(super);
136	frags_per_block = fs->blocksize / fs->fragsize;
137
138	/* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
139	set_field(s_blocks_per_group, fs->blocksize * 8);
140	if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
141		super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
142	super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;
143
144	super->s_blocks_count = param->s_blocks_count;
145	super->s_r_blocks_count = param->s_r_blocks_count;
146	if (super->s_r_blocks_count >= param->s_blocks_count) {
147		retval = EXT2_ET_INVALID_ARGUMENT;
148		goto cleanup;
149	}
150
151	/*
152	 * If we're creating an external journal device, we don't need
153	 * to bother with the rest.
154	 */
155	if (super->s_feature_incompat &
156	    EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
157		fs->group_desc_count = 0;
158		ext2fs_mark_super_dirty(fs);
159		*ret_fs = fs;
160		return 0;
161	}
162
163retry:
164	fs->group_desc_count = (super->s_blocks_count -
165				super->s_first_data_block +
166				EXT2_BLOCKS_PER_GROUP(super) - 1)
167		/ EXT2_BLOCKS_PER_GROUP(super);
168	if (fs->group_desc_count == 0)
169		return EXT2_ET_TOOSMALL;
170	fs->desc_blocks = (fs->group_desc_count +
171			   EXT2_DESC_PER_BLOCK(super) - 1)
172		/ EXT2_DESC_PER_BLOCK(super);
173
174	i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
175	set_field(s_inodes_count, super->s_blocks_count / i);
176
177	/*
178	 * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
179	 * that we have enough inodes for the filesystem(!)
180	 */
181	if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
182		super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
183
184	/*
185	 * There should be at least as many inodes as the user
186	 * requested.  Figure out how many inodes per group that
187	 * should be.  But make sure that we don't allocate more than
188	 * one bitmap's worth of inodes each group.
189	 */
190	ipg = (super->s_inodes_count + fs->group_desc_count - 1) /
191		fs->group_desc_count;
192	if (ipg > fs->blocksize * 8)
193		ipg = fs->blocksize * 8;
194
195	if (ipg > EXT2_MAX_INODES_PER_GROUP(super))
196		ipg = EXT2_MAX_INODES_PER_GROUP(super);
197
198	super->s_inodes_per_group = ipg;
199	if (super->s_inodes_count > ipg * fs->group_desc_count)
200		super->s_inodes_count = ipg * fs->group_desc_count;
201
202	/*
203	 * Make sure the number of inodes per group completely fills
204	 * the inode table blocks in the descriptor.  If not, add some
205	 * additional inodes/group.  Waste not, want not...
206	 */
207	fs->inode_blocks_per_group = (((super->s_inodes_per_group *
208					EXT2_INODE_SIZE(super)) +
209				       EXT2_BLOCK_SIZE(super) - 1) /
210				      EXT2_BLOCK_SIZE(super));
211	super->s_inodes_per_group = ((fs->inode_blocks_per_group *
212				      EXT2_BLOCK_SIZE(super)) /
213				     EXT2_INODE_SIZE(super));
214	/*
215	 * Finally, make sure the number of inodes per group is a
216	 * multiple of 8.  This is needed to simplify the bitmap
217	 * splicing code.
218	 */
219	super->s_inodes_per_group &= ~7;
220	fs->inode_blocks_per_group = (((super->s_inodes_per_group *
221					EXT2_INODE_SIZE(super)) +
222				       EXT2_BLOCK_SIZE(super) - 1) /
223				      EXT2_BLOCK_SIZE(super));
224
225	/*
226	 * adjust inode count to reflect the adjusted inodes_per_group
227	 */
228	super->s_inodes_count = super->s_inodes_per_group *
229		fs->group_desc_count;
230	super->s_free_inodes_count = super->s_inodes_count;
231
232	/*
233	 * Overhead is the number of bookkeeping blocks per group.  It
234	 * includes the superblock backup, the group descriptor
235	 * backups, the inode bitmap, the block bitmap, and the inode
236	 * table.
237	 *
238	 * XXX Not all block groups need the descriptor blocks, but
239	 * being clever is tricky...
240	 */
241	overhead = (int) (3 + fs->desc_blocks + fs->inode_blocks_per_group);
242
243	/*
244	 * See if the last group is big enough to support the
245	 * necessary data structures.  If not, we need to get rid of
246	 * it.
247	 */
248	rem = (int) ((super->s_blocks_count - super->s_first_data_block) %
249		     super->s_blocks_per_group);
250	if ((fs->group_desc_count == 1) && rem && (rem < overhead))
251		return EXT2_ET_TOOSMALL;
252	if (rem && (rem < overhead+50)) {
253		super->s_blocks_count -= rem;
254		goto retry;
255	}
256
257	/*
258	 * At this point we know how big the filesystem will be.  So
259	 * we can do any and all allocations that depend on the block
260	 * count.
261	 */
262
263	retval = ext2fs_get_mem(strlen(fs->device_name) + 80,
264				(void **) &buf);
265	if (retval)
266		goto cleanup;
267
268	sprintf(buf, "block bitmap for %s", fs->device_name);
269	retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
270	if (retval)
271		goto cleanup;
272
273	sprintf(buf, "inode bitmap for %s", fs->device_name);
274	retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
275	if (retval)
276		goto cleanup;
277
278	ext2fs_free_mem((void **) &buf);
279
280	retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize,
281				(void **) &fs->group_desc);
282	if (retval)
283		goto cleanup;
284
285	memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
286
287	/*
288	 * Reserve the superblock and group descriptors for each
289	 * group, and fill in the correct group statistics for group.
290	 * Note that although the block bitmap, inode bitmap, and
291	 * inode table have not been allocated (and in fact won't be
292	 * by this routine), they are accounted for nevertheless.
293	 */
294	group_block = super->s_first_data_block;
295	super->s_free_blocks_count = 0;
296	for (i = 0; i < fs->group_desc_count; i++) {
297		if (i == fs->group_desc_count-1) {
298			numblocks = (fs->super->s_blocks_count -
299				     fs->super->s_first_data_block) %
300					     fs->super->s_blocks_per_group;
301			if (!numblocks)
302				numblocks = fs->super->s_blocks_per_group;
303		} else
304			numblocks = fs->super->s_blocks_per_group;
305
306		has_super = ext2fs_bg_has_super(fs, i);
307
308		if (has_super) {
309			ext2fs_mark_block_bitmap(fs->block_map, group_block);
310			numblocks--;
311		}
312		meta_bg_size = (fs->blocksize /
313				sizeof (struct ext2_group_desc));
314		meta_bg = i / meta_bg_size;
315
316		if (!(fs->super->s_feature_incompat &
317		      EXT2_FEATURE_INCOMPAT_META_BG) ||
318		    (meta_bg < fs->super->s_first_meta_bg)) {
319			if (has_super) {
320				for (j=0; j < fs->desc_blocks; j++)
321					ext2fs_mark_block_bitmap(fs->block_map,
322							 group_block + j + 1);
323				numblocks -= fs->desc_blocks;
324			}
325		} else {
326			if (has_super)
327				has_super = 1;
328			if (((i % meta_bg_size) == 0) ||
329			    ((i % meta_bg_size) == 1) ||
330			    ((i % meta_bg_size) == (meta_bg_size-1))) {
331				ext2fs_mark_block_bitmap(fs->block_map,
332					 group_block + has_super);
333				numblocks--;
334			}
335		}
336
337		numblocks -= 2 + fs->inode_blocks_per_group;
338
339		super->s_free_blocks_count += numblocks;
340		fs->group_desc[i].bg_free_blocks_count = numblocks;
341		fs->group_desc[i].bg_free_inodes_count =
342			fs->super->s_inodes_per_group;
343		fs->group_desc[i].bg_used_dirs_count = 0;
344
345		group_block += super->s_blocks_per_group;
346	}
347
348	ext2fs_mark_super_dirty(fs);
349	ext2fs_mark_bb_dirty(fs);
350	ext2fs_mark_ib_dirty(fs);
351
352	io_channel_set_blksize(fs->io, fs->blocksize);
353
354	*ret_fs = fs;
355	return 0;
356cleanup:
357	ext2fs_free(fs);
358	return retval;
359}
360
361
362
363