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 * 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 unsigned 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 = EXT2_DESC_PER_BLOCK(sb);
71	unsigned long max_blocks = 0xffffffff;
72	unsigned long rsv_groups;
73	unsigned 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 = ext2fs_div_ceil(max_blocks - sb->s_first_data_block, bpg);
81	rsv_gdb = ext2fs_div_ceil(rsv_groups, 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 = %u\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	unsigned int	ipg;
103	dgrp_t		i;
104	blk_t		numblocks;
105	int		rsv_gdt;
106	int		csum_flag;
107	int		io_flags;
108	char		*buf = 0;
109	char		c;
110
111	if (!param || !param->s_blocks_count)
112		return EXT2_ET_INVALID_ARGUMENT;
113
114	retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
115	if (retval)
116		return retval;
117
118	memset(fs, 0, sizeof(struct struct_ext2_filsys));
119	fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
120	fs->flags = flags | EXT2_FLAG_RW;
121	fs->umask = 022;
122#ifdef WORDS_BIGENDIAN
123	fs->flags |= EXT2_FLAG_SWAP_BYTES;
124#endif
125	io_flags = IO_FLAG_RW;
126	if (flags & EXT2_FLAG_EXCLUSIVE)
127		io_flags |= IO_FLAG_EXCLUSIVE;
128	retval = manager->open(name, io_flags, &fs->io);
129	if (retval)
130		goto cleanup;
131	fs->image_io = fs->io;
132	fs->io->app_data = fs;
133	retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
134	if (retval)
135		goto cleanup;
136
137	strcpy(fs->device_name, name);
138	retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super);
139	if (retval)
140		goto cleanup;
141	fs->super = super;
142
143	memset(super, 0, SUPERBLOCK_SIZE);
144
145#define set_field(field, default) (super->field = param->field ? \
146				   param->field : (default))
147
148	super->s_magic = EXT2_SUPER_MAGIC;
149	super->s_state = EXT2_VALID_FS;
150
151	set_field(s_log_block_size, 0);	/* default blocksize: 1024 bytes */
152	set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
153	set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
154	set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
155	set_field(s_errors, EXT2_ERRORS_DEFAULT);
156	set_field(s_feature_compat, 0);
157	set_field(s_feature_incompat, 0);
158	set_field(s_feature_ro_compat, 0);
159	set_field(s_first_meta_bg, 0);
160	set_field(s_raid_stride, 0);		/* default stride size: 0 */
161	set_field(s_raid_stripe_width, 0);	/* default stripe width: 0 */
162	set_field(s_log_groups_per_flex, 0);
163	set_field(s_flags, 0);
164	if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
165		retval = EXT2_ET_UNSUPP_FEATURE;
166		goto cleanup;
167	}
168	if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
169		retval = EXT2_ET_RO_UNSUPP_FEATURE;
170		goto cleanup;
171	}
172
173	set_field(s_rev_level, EXT2_GOOD_OLD_REV);
174	if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
175		set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
176		set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
177		if (super->s_inode_size >= sizeof(struct ext2_inode_large)) {
178			int extra_isize = sizeof(struct ext2_inode_large) -
179				EXT2_GOOD_OLD_INODE_SIZE;
180			set_field(s_min_extra_isize, extra_isize);
181			set_field(s_want_extra_isize, extra_isize);
182		}
183	} else {
184		super->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
185		super->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
186	}
187
188	set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
189	super->s_mkfs_time = super->s_lastcheck = fs->now ? fs->now : time(NULL);
190
191	super->s_creator_os = CREATOR_OS;
192
193	fs->blocksize = EXT2_BLOCK_SIZE(super);
194	fs->fragsize = EXT2_FRAG_SIZE(super);
195	frags_per_block = fs->blocksize / fs->fragsize;
196
197	/* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
198	set_field(s_blocks_per_group, fs->blocksize * 8);
199	if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
200		super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
201	super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;
202
203	super->s_blocks_count = param->s_blocks_count;
204	super->s_r_blocks_count = param->s_r_blocks_count;
205	if (super->s_r_blocks_count >= param->s_blocks_count) {
206		retval = EXT2_ET_INVALID_ARGUMENT;
207		goto cleanup;
208	}
209
210	/*
211	 * If we're creating an external journal device, we don't need
212	 * to bother with the rest.
213	 */
214	if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
215		fs->group_desc_count = 0;
216		ext2fs_mark_super_dirty(fs);
217		*ret_fs = fs;
218		return 0;
219	}
220
221retry:
222	fs->group_desc_count = ext2fs_div_ceil(super->s_blocks_count -
223					       super->s_first_data_block,
224					       EXT2_BLOCKS_PER_GROUP(super));
225	if (fs->group_desc_count == 0) {
226		retval = EXT2_ET_TOOSMALL;
227		goto cleanup;
228	}
229	fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
230					  EXT2_DESC_PER_BLOCK(super));
231
232	i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
233	set_field(s_inodes_count, super->s_blocks_count / i);
234
235	/*
236	 * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
237	 * that we have enough inodes for the filesystem(!)
238	 */
239	if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
240		super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
241
242	/*
243	 * There should be at least as many inodes as the user
244	 * requested.  Figure out how many inodes per group that
245	 * should be.  But make sure that we don't allocate more than
246	 * one bitmap's worth of inodes each group.
247	 */
248	ipg = ext2fs_div_ceil(super->s_inodes_count, fs->group_desc_count);
249	if (ipg > fs->blocksize * 8) {
250		if (super->s_blocks_per_group >= 256) {
251			/* Try again with slightly different parameters */
252			super->s_blocks_per_group -= 8;
253			super->s_blocks_count = param->s_blocks_count;
254			super->s_frags_per_group = super->s_blocks_per_group *
255				frags_per_block;
256			goto retry;
257		} else {
258			retval = EXT2_ET_TOO_MANY_INODES;
259			goto cleanup;
260		}
261	}
262
263	if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super))
264		ipg = EXT2_MAX_INODES_PER_GROUP(super);
265
266ipg_retry:
267	super->s_inodes_per_group = ipg;
268
269	/*
270	 * Make sure the number of inodes per group completely fills
271	 * the inode table blocks in the descriptor.  If not, add some
272	 * additional inodes/group.  Waste not, want not...
273	 */
274	fs->inode_blocks_per_group = (((super->s_inodes_per_group *
275					EXT2_INODE_SIZE(super)) +
276				       EXT2_BLOCK_SIZE(super) - 1) /
277				      EXT2_BLOCK_SIZE(super));
278	super->s_inodes_per_group = ((fs->inode_blocks_per_group *
279				      EXT2_BLOCK_SIZE(super)) /
280				     EXT2_INODE_SIZE(super));
281	/*
282	 * Finally, make sure the number of inodes per group is a
283	 * multiple of 8.  This is needed to simplify the bitmap
284	 * splicing code.
285	 */
286	super->s_inodes_per_group &= ~7;
287	fs->inode_blocks_per_group = (((super->s_inodes_per_group *
288					EXT2_INODE_SIZE(super)) +
289				       EXT2_BLOCK_SIZE(super) - 1) /
290				      EXT2_BLOCK_SIZE(super));
291
292	/*
293	 * adjust inode count to reflect the adjusted inodes_per_group
294	 */
295	if ((__u64)super->s_inodes_per_group * fs->group_desc_count > ~0U) {
296		ipg--;
297		goto ipg_retry;
298	}
299	super->s_inodes_count = super->s_inodes_per_group *
300		fs->group_desc_count;
301	super->s_free_inodes_count = super->s_inodes_count;
302
303	/*
304	 * check the number of reserved group descriptor table blocks
305	 */
306	if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE)
307		rsv_gdt = calc_reserved_gdt_blocks(fs);
308	else
309		rsv_gdt = 0;
310	set_field(s_reserved_gdt_blocks, rsv_gdt);
311	if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) {
312		retval = EXT2_ET_RES_GDT_BLOCKS;
313		goto cleanup;
314	}
315
316	/*
317	 * Calculate the maximum number of bookkeeping blocks per
318	 * group.  It includes the superblock, the block group
319	 * descriptors, the block bitmap, the inode bitmap, the inode
320	 * table, and the reserved gdt blocks.
321	 */
322	overhead = (int) (3 + fs->inode_blocks_per_group +
323			  fs->desc_blocks + super->s_reserved_gdt_blocks);
324
325	/* This can only happen if the user requested too many inodes */
326	if (overhead > super->s_blocks_per_group) {
327		retval = EXT2_ET_TOO_MANY_INODES;
328		goto cleanup;
329	}
330
331	/*
332	 * See if the last group is big enough to support the
333	 * necessary data structures.  If not, we need to get rid of
334	 * it.  We need to recalculate the overhead for the last block
335	 * group, since it might or might not have a superblock
336	 * backup.
337	 */
338	overhead = (int) (2 + fs->inode_blocks_per_group);
339	if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1))
340		overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks;
341	rem = ((super->s_blocks_count - super->s_first_data_block) %
342	       super->s_blocks_per_group);
343	if ((fs->group_desc_count == 1) && rem && (rem < overhead)) {
344		retval = EXT2_ET_TOOSMALL;
345		goto cleanup;
346	}
347	if (rem && (rem < overhead+50)) {
348		super->s_blocks_count -= rem;
349		goto retry;
350	}
351
352	/*
353	 * At this point we know how big the filesystem will be.  So
354	 * we can do any and all allocations that depend on the block
355	 * count.
356	 */
357
358	retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
359	if (retval)
360		goto cleanup;
361
362	strcpy(buf, "block bitmap for ");
363	strcat(buf, fs->device_name);
364	retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
365	if (retval)
366		goto cleanup;
367
368	strcpy(buf, "inode bitmap for ");
369	strcat(buf, fs->device_name);
370	retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
371	if (retval)
372		goto cleanup;
373
374	ext2fs_free_mem(&buf);
375
376	retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
377				&fs->group_desc);
378	if (retval)
379		goto cleanup;
380
381	memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
382
383	/*
384	 * Reserve the superblock and group descriptors for each
385	 * group, and fill in the correct group statistics for group.
386	 * Note that although the block bitmap, inode bitmap, and
387	 * inode table have not been allocated (and in fact won't be
388	 * by this routine), they are accounted for nevertheless.
389	 *
390	 * If FLEX_BG meta-data grouping is used, only account for the
391	 * superblock and group descriptors (the inode tables and
392	 * bitmaps will be accounted for when allocated).
393	 */
394	super->s_free_blocks_count = 0;
395	csum_flag = EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
396					       EXT4_FEATURE_RO_COMPAT_GDT_CSUM);
397	for (i = 0; i < fs->group_desc_count; i++) {
398		/*
399		 * Don't set the BLOCK_UNINIT group for the last group
400		 * because the block bitmap needs to be padded.
401		 */
402		if (csum_flag) {
403			if (i != fs->group_desc_count - 1)
404				fs->group_desc[i].bg_flags |=
405					EXT2_BG_BLOCK_UNINIT;
406			fs->group_desc[i].bg_flags |= EXT2_BG_INODE_UNINIT;
407			numblocks = super->s_inodes_per_group;
408			if (i == 0)
409				numblocks -= super->s_first_ino;
410			fs->group_desc[i].bg_itable_unused = numblocks;
411		}
412		numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
413		if (fs->super->s_log_groups_per_flex)
414			numblocks += 2 + fs->inode_blocks_per_group;
415
416		super->s_free_blocks_count += numblocks;
417		fs->group_desc[i].bg_free_blocks_count = numblocks;
418		fs->group_desc[i].bg_free_inodes_count =
419			fs->super->s_inodes_per_group;
420		fs->group_desc[i].bg_used_dirs_count = 0;
421		ext2fs_group_desc_csum_set(fs, i);
422	}
423
424	c = (char) 255;
425	if (((int) c) == -1) {
426		super->s_flags |= EXT2_FLAGS_SIGNED_HASH;
427	} else {
428		super->s_flags |= EXT2_FLAGS_UNSIGNED_HASH;
429	}
430
431	ext2fs_mark_super_dirty(fs);
432	ext2fs_mark_bb_dirty(fs);
433	ext2fs_mark_ib_dirty(fs);
434
435	io_channel_set_blksize(fs->io, fs->blocksize);
436
437	*ret_fs = fs;
438	return 0;
439cleanup:
440	free(buf);
441	ext2fs_free(fs);
442	return retval;
443}
444