initialize.c revision 412376efff3c0e0c2fea00666c2457e6f2ae1878 
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 Library
9 * General Public License, version 2.
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 * Calculate the number of GDT blocks to reserve for online filesystem growth.
50 * The absolute maximum number of GDT blocks we can reserve is determined by
51 * the number of block pointers that can fit into a single block.
52 */
53static unsigned int calc_reserved_gdt_blocks(ext2_filsys fs)
54{
55	struct ext2_super_block *sb = fs->super;
56	unsigned long bpg = sb->s_blocks_per_group;
57	unsigned int gdpb = EXT2_DESC_PER_BLOCK(sb);
58	unsigned long max_blocks = 0xffffffff;
59	unsigned long rsv_groups;
60	unsigned int rsv_gdb;
61
62	/* We set it at 1024x the current filesystem size, or
63	 * the upper block count limit (2^32), whichever is lower.
64	 */
65	if (sb->s_blocks_count < max_blocks / 1024)
66		max_blocks = sb->s_blocks_count * 1024;
67	rsv_groups = ext2fs_div_ceil(max_blocks - sb->s_first_data_block, bpg);
68	rsv_gdb = ext2fs_div_ceil(rsv_groups, gdpb) - fs->desc_blocks;
69	if (rsv_gdb > EXT2_ADDR_PER_BLOCK(sb))
70		rsv_gdb = EXT2_ADDR_PER_BLOCK(sb);
71#ifdef RES_GDT_DEBUG
72	printf("max_blocks %lu, rsv_groups = %lu, rsv_gdb = %u\n",
73	       max_blocks, rsv_groups, rsv_gdb);
74#endif
75
76	return rsv_gdb;
77}
78
79errcode_t ext2fs_initialize(const char *name, int flags,
80			    struct ext2_super_block *param,
81			    io_manager manager, ext2_filsys *ret_fs)
82{
83	ext2_filsys	fs;
84	errcode_t	retval;
85	struct ext2_super_block *super;
86	unsigned int	rem;
87	unsigned int	overhead = 0;
88	unsigned int	ipg;
89	dgrp_t		i;
90	blk_t		numblocks;
91	int		rsv_gdt;
92	int		csum_flag;
93	int		io_flags;
94	char		*buf = 0;
95	char		c;
96
97	if (!param || !param->s_blocks_count)
98		return EXT2_ET_INVALID_ARGUMENT;
99
100	retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
101	if (retval)
102		return retval;
103
104	memset(fs, 0, sizeof(struct struct_ext2_filsys));
105	fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
106	fs->flags = flags | EXT2_FLAG_RW;
107	fs->umask = 022;
108#ifdef WORDS_BIGENDIAN
109	fs->flags |= EXT2_FLAG_SWAP_BYTES;
110#endif
111	io_flags = IO_FLAG_RW;
112	if (flags & EXT2_FLAG_EXCLUSIVE)
113		io_flags |= IO_FLAG_EXCLUSIVE;
114	retval = manager->open(name, io_flags, &fs->io);
115	if (retval)
116		goto cleanup;
117	fs->image_io = fs->io;
118	fs->io->app_data = fs;
119	retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
120	if (retval)
121		goto cleanup;
122
123	strcpy(fs->device_name, name);
124	retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super);
125	if (retval)
126		goto cleanup;
127	fs->super = super;
128
129	memset(super, 0, SUPERBLOCK_SIZE);
130
131#define set_field(field, default) (super->field = param->field ? \
132				   param->field : (default))
133
134	super->s_magic = EXT2_SUPER_MAGIC;
135	super->s_state = EXT2_VALID_FS;
136
137	set_field(s_log_block_size, 0);	/* default blocksize: 1024 bytes */
138	set_field(s_log_cluster_size, 0);
139	set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
140	set_field(s_max_mnt_count, 0);
141	set_field(s_errors, EXT2_ERRORS_DEFAULT);
142	set_field(s_feature_compat, 0);
143	set_field(s_feature_incompat, 0);
144	set_field(s_feature_ro_compat, 0);
145	set_field(s_default_mount_opts, 0);
146	set_field(s_first_meta_bg, 0);
147	set_field(s_raid_stride, 0);		/* default stride size: 0 */
148	set_field(s_raid_stripe_width, 0);	/* default stripe width: 0 */
149	set_field(s_log_groups_per_flex, 0);
150	set_field(s_flags, 0);
151	if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
152		retval = EXT2_ET_UNSUPP_FEATURE;
153		goto cleanup;
154	}
155	if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
156		retval = EXT2_ET_RO_UNSUPP_FEATURE;
157		goto cleanup;
158	}
159
160	set_field(s_rev_level, EXT2_GOOD_OLD_REV);
161	if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
162		set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
163		set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
164		if (super->s_inode_size >= sizeof(struct ext2_inode_large)) {
165			int extra_isize = sizeof(struct ext2_inode_large) -
166				EXT2_GOOD_OLD_INODE_SIZE;
167			set_field(s_min_extra_isize, extra_isize);
168			set_field(s_want_extra_isize, extra_isize);
169		}
170	} else {
171		super->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
172		super->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
173	}
174
175	set_field(s_checkinterval, 0);
176	super->s_mkfs_time = super->s_lastcheck = fs->now ? fs->now : time(NULL);
177
178	super->s_creator_os = CREATOR_OS;
179
180	fs->blocksize = EXT2_BLOCK_SIZE(super);
181	fs->clustersize = EXT2_CLUSTER_SIZE(super);
182
183	/* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
184	set_field(s_blocks_per_group, fs->blocksize * 8);
185	if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
186		super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
187	super->s_clusters_per_group = super->s_blocks_per_group;
188
189	super->s_blocks_count = param->s_blocks_count;
190	super->s_r_blocks_count = param->s_r_blocks_count;
191	if (super->s_r_blocks_count >= param->s_blocks_count) {
192		retval = EXT2_ET_INVALID_ARGUMENT;
193		goto cleanup;
194	}
195
196	/*
197	 * If we're creating an external journal device, we don't need
198	 * to bother with the rest.
199	 */
200	if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
201		fs->group_desc_count = 0;
202		ext2fs_mark_super_dirty(fs);
203		*ret_fs = fs;
204		return 0;
205	}
206
207retry:
208	fs->group_desc_count = ext2fs_div_ceil(super->s_blocks_count -
209					       super->s_first_data_block,
210					       EXT2_BLOCKS_PER_GROUP(super));
211	if (fs->group_desc_count == 0) {
212		retval = EXT2_ET_TOOSMALL;
213		goto cleanup;
214	}
215	fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
216					  EXT2_DESC_PER_BLOCK(super));
217
218	i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
219	set_field(s_inodes_count, super->s_blocks_count / i);
220
221	/*
222	 * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
223	 * that we have enough inodes for the filesystem(!)
224	 */
225	if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
226		super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
227
228	/*
229	 * There should be at least as many inodes as the user
230	 * requested.  Figure out how many inodes per group that
231	 * should be.  But make sure that we don't allocate more than
232	 * one bitmap's worth of inodes each group.
233	 */
234	ipg = ext2fs_div_ceil(super->s_inodes_count, 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_clusters_per_group = super->s_blocks_per_group;
241			goto retry;
242		} else {
243			retval = EXT2_ET_TOO_MANY_INODES;
244			goto cleanup;
245		}
246	}
247
248	if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super))
249		ipg = EXT2_MAX_INODES_PER_GROUP(super);
250
251ipg_retry:
252	super->s_inodes_per_group = ipg;
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	if ((__u64)super->s_inodes_per_group * fs->group_desc_count > ~0U) {
281		ipg--;
282		goto ipg_retry;
283	}
284	super->s_inodes_count = super->s_inodes_per_group *
285		fs->group_desc_count;
286	super->s_free_inodes_count = super->s_inodes_count;
287
288	/*
289	 * check the number of reserved group descriptor table blocks
290	 */
291	if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE)
292		rsv_gdt = calc_reserved_gdt_blocks(fs);
293	else
294		rsv_gdt = 0;
295	set_field(s_reserved_gdt_blocks, rsv_gdt);
296	if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) {
297		retval = EXT2_ET_RES_GDT_BLOCKS;
298		goto cleanup;
299	}
300
301	/*
302	 * Calculate the maximum number of bookkeeping blocks per
303	 * group.  It includes the superblock, the block group
304	 * descriptors, the block bitmap, the inode bitmap, the inode
305	 * table, and the reserved gdt blocks.
306	 */
307	overhead = (int) (3 + fs->inode_blocks_per_group +
308			  fs->desc_blocks + super->s_reserved_gdt_blocks);
309
310	/* This can only happen if the user requested too many inodes */
311	if (overhead > super->s_blocks_per_group) {
312		retval = EXT2_ET_TOO_MANY_INODES;
313		goto cleanup;
314	}
315
316	/*
317	 * See if the last group is big enough to support the
318	 * necessary data structures.  If not, we need to get rid of
319	 * it.  We need to recalculate the overhead for the last block
320	 * group, since it might or might not have a superblock
321	 * backup.
322	 */
323	overhead = (int) (2 + fs->inode_blocks_per_group);
324	if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1))
325		overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks;
326	rem = ((super->s_blocks_count - super->s_first_data_block) %
327	       super->s_blocks_per_group);
328	if ((fs->group_desc_count == 1) && rem && (rem < overhead)) {
329		retval = EXT2_ET_TOOSMALL;
330		goto cleanup;
331	}
332	if (rem && (rem < overhead+50)) {
333		super->s_blocks_count -= rem;
334		goto retry;
335	}
336
337	/*
338	 * At this point we know how big the filesystem will be.  So
339	 * we can do any and all allocations that depend on the block
340	 * count.
341	 */
342
343	retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
344	if (retval)
345		goto cleanup;
346
347	strcpy(buf, "block bitmap for ");
348	strcat(buf, fs->device_name);
349	retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
350	if (retval)
351		goto cleanup;
352
353	strcpy(buf, "inode bitmap for ");
354	strcat(buf, fs->device_name);
355	retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
356	if (retval)
357		goto cleanup;
358
359	ext2fs_free_mem(&buf);
360
361	retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
362				&fs->group_desc);
363	if (retval)
364		goto cleanup;
365
366	memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
367
368	/*
369	 * Reserve the superblock and group descriptors for each
370	 * group, and fill in the correct group statistics for group.
371	 * Note that although the block bitmap, inode bitmap, and
372	 * inode table have not been allocated (and in fact won't be
373	 * by this routine), they are accounted for nevertheless.
374	 *
375	 * If FLEX_BG meta-data grouping is used, only account for the
376	 * superblock and group descriptors (the inode tables and
377	 * bitmaps will be accounted for when allocated).
378	 */
379	super->s_free_blocks_count = 0;
380	csum_flag = EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
381					       EXT4_FEATURE_RO_COMPAT_GDT_CSUM);
382	for (i = 0; i < fs->group_desc_count; i++) {
383		/*
384		 * Don't set the BLOCK_UNINIT group for the last group
385		 * because the block bitmap needs to be padded.
386		 */
387		if (csum_flag) {
388			if (i != fs->group_desc_count - 1)
389				fs->group_desc[i].bg_flags |=
390					EXT2_BG_BLOCK_UNINIT;
391			fs->group_desc[i].bg_flags |= EXT2_BG_INODE_UNINIT;
392			numblocks = super->s_inodes_per_group;
393			if (i == 0)
394				numblocks -= super->s_first_ino;
395			fs->group_desc[i].bg_itable_unused = numblocks;
396		}
397		numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
398		if (fs->super->s_log_groups_per_flex)
399			numblocks += 2 + fs->inode_blocks_per_group;
400
401		super->s_free_blocks_count += numblocks;
402		fs->group_desc[i].bg_free_blocks_count = numblocks;
403		fs->group_desc[i].bg_free_inodes_count =
404			fs->super->s_inodes_per_group;
405		fs->group_desc[i].bg_used_dirs_count = 0;
406		ext2fs_group_desc_csum_set(fs, i);
407	}
408
409	c = (char) 255;
410	if (((int) c) == -1) {
411		super->s_flags |= EXT2_FLAGS_SIGNED_HASH;
412	} else {
413		super->s_flags |= EXT2_FLAGS_UNSIGNED_HASH;
414	}
415
416	ext2fs_mark_super_dirty(fs);
417	ext2fs_mark_bb_dirty(fs);
418	ext2fs_mark_ib_dirty(fs);
419
420	io_channel_set_blksize(fs->io, fs->blocksize);
421
422	*ret_fs = fs;
423	return 0;
424cleanup:
425	free(buf);
426	ext2fs_free(fs);
427	return retval;
428}
429