mke2fs.c revision 1.14
1/*	$NetBSD: mke2fs.c,v 1.14 2010/09/10 15:51:20 tsutsui Exp $	*/
2
3/*-
4 * Copyright (c) 2007 Izumi Tsutsui.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27/*
28 * Copyright (c) 1980, 1989, 1993
29 *	The Regents of the University of California.  All rights reserved.
30 *
31 * Redistribution and use in source and binary forms, with or without
32 * modification, are permitted provided that the following conditions
33 * are met:
34 * 1. Redistributions of source code must retain the above copyright
35 *    notice, this list of conditions and the following disclaimer.
36 * 2. Redistributions in binary form must reproduce the above copyright
37 *    notice, this list of conditions and the following disclaimer in the
38 *    documentation and/or other materials provided with the distribution.
39 * 3. Neither the name of the University nor the names of its contributors
40 *    may be used to endorse or promote products derived from this software
41 *    without specific prior written permission.
42 *
43 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
44 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
45 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
46 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
47 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
48 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
49 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
50 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
51 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
52 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
53 * SUCH DAMAGE.
54 */
55
56/*
57 * Copyright (c) 1997 Manuel Bouyer.
58 *
59 * Redistribution and use in source and binary forms, with or without
60 * modification, are permitted provided that the following conditions
61 * are met:
62 * 1. Redistributions of source code must retain the above copyright
63 *	notice, this list of conditions and the following disclaimer.
64 * 2. Redistributions in binary form must reproduce the above copyright
65 *	notice, this list of conditions and the following disclaimer in the
66 *	documentation and/or other materials provided with the distribution.
67 *
68 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
69 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
70 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
71 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
72 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
73 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
74 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
75 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
76 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
77 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
78 */
79
80/*
81 * mke2fs.c: "re-invent (dumb but non-GPLed) wheel as a fun project"
82 *
83 *	In spite of this name, there is no piece of code
84 *	derived from GPLed e2fsprogs written for Linux.
85 *	I referred them only to see how each structure
86 *	member should be initialized.
87 *
88 * Reference:
89 *	- All NetBSD sources under src/sys/ufs/ext2fs and src/sbin/fsck_ext2fs
90 *	- Ext2fs Home Page
91 *		http://e2fsprogs.sourceforge.net/ext2.html
92 *	- Design and Implementation of the Second Extended Filesystem
93 *		http://e2fsprogs.sourceforge.net/ext2intro.html
94 *	- Linux Documentation "The Second Extended Filesystem"
95 *		http://www.kernel.org/doc/Documentation/filesystems/ext2.txt
96 */
97
98#include <sys/cdefs.h>
99#ifndef lint
100#if 0
101static char sccsid[] = "@(#)mkfs.c	8.11 (Berkeley) 5/3/95";
102#else
103__RCSID("$NetBSD: mke2fs.c,v 1.14 2010/09/10 15:51:20 tsutsui Exp $");
104#endif
105#endif /* not lint */
106
107#include <sys/param.h>
108#include <sys/mman.h>
109#include <sys/time.h>
110#include <ufs/ext2fs/ext2fs_dinode.h>
111#include <ufs/ext2fs/ext2fs_dir.h>
112#include <ufs/ext2fs/ext2fs.h>
113#include <sys/ioctl.h>
114
115#include <err.h>
116#include <errno.h>
117#include <string.h>
118#include <unistd.h>
119#include <stdlib.h>
120#include <stddef.h>
121#include <stdio.h>
122#include <uuid.h>
123
124#include "extern.h"
125
126static void initcg(uint);
127static void zap_old_sblock(daddr_t);
128static uint cgoverhead(uint);
129static int fsinit(const struct timeval *);
130static int makedir(struct ext2fs_direct *, int);
131static void copy_dir(struct ext2fs_direct *, struct ext2fs_direct *);
132static void init_resizeino(const struct timeval *);
133static uint32_t alloc(uint32_t, uint16_t);
134static void iput(struct ext2fs_dinode *, ino_t);
135static void rdfs(daddr_t, int, void *);
136static void wtfs(daddr_t, int, void *);
137static int ilog2(uint);
138static int skpc(int, size_t, uint8_t *);
139
140/* XXX: some of these macro should be into <ufs/ext2fs/ext2fs.h>? */
141#define EXT2_DEF_MAX_MNT_COUNT	20
142#define EXT2_DEF_FSCKINTV	(180 * 24 * 60 * 60)	/* 180 days */
143#define EXT2_RESERVED_INODES	(EXT2_FIRSTINO - 1)
144#define EXT2_UMASK		0755
145
146#define EXT2_INO_INDEX(ino)	((ino) - 1)		/* no inode zero */
147
148#define EXT2_LOSTFOUNDSIZE	16384
149#define EXT2_LOSTFOUNDINO	EXT2_FIRSTINO		/* XXX: not quite */
150#define EXT2_LOSTFOUNDUMASK	0700
151
152#define EXT2_RESIZEINOUMASK	0600
153
154#define NBLOCK_SUPERBLOCK	1
155#define NBLOCK_BLOCK_BITMAP	1
156#define NBLOCK_INODE_BITMAP	1
157
158#define cgbase(fs, c)	\
159	((fs)->e2fs.e2fs_first_dblock + (fs)->e2fs.e2fs_bpg * (c))
160
161
162/*
163 * ext2fs super block and group descriptor structures
164 *
165 *   We don't have to use or setup whole in-memory m_ext2fs structure,
166 *   but prepare it to use several macro defined in kernel headers.
167 */
168union {
169	struct m_ext2fs m_ext2fs;
170	char pad[SBSIZE];
171} ext2fsun;
172#define sblock	ext2fsun.m_ext2fs
173#define gd	ext2fsun.m_ext2fs.e2fs_gd
174
175static uint8_t *iobuf;		/* for superblock and group descriptors */
176static int iobufsize;
177
178static uint8_t buf[MAXBSIZE];	/* for initcg() and makedir() ops */
179
180static int fsi, fso;
181
182void
183mke2fs(const char *fsys, int fi, int fo)
184{
185	struct timeval tv;
186	int64_t minfssize;
187	uint bcount, fbcount, ficount;
188	uint blocks_gd, blocks_per_cg, inodes_per_cg, iblocks_per_cg;
189	uint minblocks_per_cg, blocks_lastcg;
190	uint ncg, cylno, sboff;
191	uuid_t uuid;
192	uint32_t uustat;
193	int i, len, col, delta, fld_width, max_cols;
194	struct winsize winsize;
195
196	gettimeofday(&tv, NULL);
197	fsi = fi;
198	fso = fo;
199
200	/*
201	 * collect and verify the block and fragment sizes
202	 */
203	if (!powerof2(bsize)) {
204		errx(EXIT_FAILURE,
205		    "block size must be a power of 2, not %u\n",
206		    bsize);
207	}
208	if (!powerof2(fsize)) {
209		errx(EXIT_FAILURE,
210		    "fragment size must be a power of 2, not %u\n",
211		    fsize);
212	}
213	if (fsize < sectorsize) {
214		errx(EXIT_FAILURE,
215		    "fragment size %u is too small, minimum is %u\n",
216		    fsize, sectorsize);
217	}
218	if (bsize < MINBSIZE) {
219		errx(EXIT_FAILURE,
220		    "block size %u is too small, minimum is %u\n",
221		    bsize, MINBSIZE);
222	}
223	if (bsize > EXT2_MAXBSIZE) {
224		errx(EXIT_FAILURE,
225		    "block size %u is too large, maximum is %u\n",
226		    bsize, MAXBSIZE);
227	}
228	if (bsize != fsize) {
229		/*
230		 * There is no fragment support on current ext2fs (yet?),
231		 * but some kernel code refers fsize or fpg as bsize or bpg
232		 * and Linux seems to set the same values to them.
233		 */
234		errx(EXIT_FAILURE,
235		    "block size (%u) can't be different from "
236		    "fragment size (%u)\n",
237		    bsize, fsize);
238	}
239
240	/* variable inodesize is REV1 feature */
241	if (Oflag == 0 && inodesize != EXT2_REV0_DINODE_SIZE) {
242		errx(EXIT_FAILURE, "GOOD_OLD_REV file system format"
243		    " doesn't support %d byte inode\n", inodesize);
244	}
245
246	sblock.e2fs.e2fs_log_bsize = ilog2(bsize) - LOG_MINBSIZE;
247	/* Umm, why not e2fs_log_fsize? */
248	sblock.e2fs.e2fs_fsize = ilog2(fsize) - LOG_MINBSIZE;
249
250	sblock.e2fs_bsize = bsize;
251	sblock.e2fs_bshift = sblock.e2fs.e2fs_log_bsize + LOG_MINBSIZE;
252	sblock.e2fs_qbmask = sblock.e2fs_bsize - 1;
253	sblock.e2fs_bmask = ~sblock.e2fs_qbmask;
254	sblock.e2fs_fsbtodb = ilog2(sblock.e2fs_bsize) - ilog2(sectorsize);
255	sblock.e2fs_ipb = sblock.e2fs_bsize / inodesize;
256
257	/*
258	 * Ext2fs preserves BBSIZE (1024 bytes) space at the top for
259	 * bootloader (though it is not enough at all for our bootloader).
260	 * If bsize == BBSIZE we have to preserve one block.
261	 * If bsize > BBSIZE, the first block already contains BBSIZE space
262	 * before superblock because superblock is allocated at SBOFF and
263	 * bsize is a power of two (i.e. 2048 bytes or more).
264	 */
265	sblock.e2fs.e2fs_first_dblock = (sblock.e2fs_bsize > BBSIZE) ? 0 : 1;
266	minfssize = fsbtodb(&sblock,
267	    sblock.e2fs.e2fs_first_dblock +
268	    NBLOCK_SUPERBLOCK +
269	    1 /* at least one group descriptor */ +
270	    NBLOCK_BLOCK_BITMAP	+
271	    NBLOCK_INODE_BITMAP +
272	    1 /* at least one inode table block */ +
273	    1 /* at least one data block for rootdir */ +
274	    1 /* at least one data block for data */
275	    );			/* XXX and more? */
276
277	if (fssize < minfssize)
278		errx(EXIT_FAILURE, "Filesystem size %" PRId64
279		    " < minimum size of %" PRId64 "\n", fssize, minfssize);
280
281	bcount = dbtofsb(&sblock, fssize);
282
283	/*
284	 * While many people claim that ext2fs is a (bad) clone of ufs/ffs,
285	 * it isn't actual ffs so maybe we should call it "block group"
286	 * as their native name rather than ffs derived "cylinder group."
287	 * But we'll use the latter here since other kernel sources use it.
288	 * (I also agree "cylinder" based allocation is obsolete though)
289	 */
290
291	/* maybe "simple is the best" */
292	blocks_per_cg = sblock.e2fs_bsize * NBBY;
293
294	ncg = howmany(bcount - sblock.e2fs.e2fs_first_dblock, blocks_per_cg);
295	blocks_gd = howmany(sizeof(struct ext2_gd) * ncg, bsize);
296
297	/* check range of inode number */
298	if (num_inodes < EXT2_FIRSTINO)
299		num_inodes = EXT2_FIRSTINO;	/* needs reserved inodes + 1 */
300	if (num_inodes > UINT16_MAX * ncg)
301		num_inodes = UINT16_MAX * ncg;	/* ext2bgd_nifree is uint16_t */
302
303	inodes_per_cg = num_inodes / ncg;
304	iblocks_per_cg = howmany(inodesize * inodes_per_cg, bsize);
305
306	/* Check that the last cylinder group has enough space for inodes */
307	minblocks_per_cg =
308	    NBLOCK_BLOCK_BITMAP +
309	    NBLOCK_INODE_BITMAP +
310	    iblocks_per_cg +
311	    1;	/* at least one data block */
312	if (Oflag == 0 || cg_has_sb(ncg - 1) != 0)
313		minblocks_per_cg += NBLOCK_SUPERBLOCK + blocks_gd;
314
315	blocks_lastcg = bcount - sblock.e2fs.e2fs_first_dblock -
316	    blocks_per_cg * (ncg - 1);
317	if (blocks_lastcg < minblocks_per_cg) {
318		/*
319		 * Since we make all the cylinder groups the same size, the
320		 * last will only be small if there are more than one
321		 * cylinder groups. If the last one is too small to store
322		 * filesystem data, just kill it.
323		 *
324		 * XXX: Does fsck_ext2fs(8) properly handle this case?
325		 */
326		bcount -= blocks_lastcg;
327		ncg--;
328		blocks_lastcg = blocks_per_cg;
329		blocks_gd = howmany(sizeof(struct ext2_gd) * ncg, bsize);
330		inodes_per_cg = num_inodes / ncg;
331	}
332	/* roundup inodes_per_cg to make it use whole inode table blocks */
333	inodes_per_cg = roundup(inodes_per_cg, sblock.e2fs_ipb);
334	num_inodes = inodes_per_cg * ncg;
335	iblocks_per_cg = inodes_per_cg / sblock.e2fs_ipb;
336
337	/* XXX: probably we should check these adjusted values again */
338
339	sblock.e2fs.e2fs_bcount = bcount;
340	sblock.e2fs.e2fs_icount = num_inodes;
341
342	sblock.e2fs_ncg = ncg;
343	sblock.e2fs_ngdb = blocks_gd;
344	sblock.e2fs_itpg = iblocks_per_cg;
345
346	sblock.e2fs.e2fs_rbcount = sblock.e2fs.e2fs_bcount * minfree / 100;
347	/* e2fs_fbcount will be accounted later */
348	/* e2fs_ficount will be accounted later */
349
350	sblock.e2fs.e2fs_bpg = blocks_per_cg;
351	sblock.e2fs.e2fs_fpg = blocks_per_cg;
352
353	sblock.e2fs.e2fs_ipg = inodes_per_cg;
354
355	sblock.e2fs.e2fs_mtime = 0;
356	sblock.e2fs.e2fs_wtime = tv.tv_sec;
357	sblock.e2fs.e2fs_mnt_count = 0;
358	/* XXX: should add some entropy to avoid checking all fs at once? */
359	sblock.e2fs.e2fs_max_mnt_count = EXT2_DEF_MAX_MNT_COUNT;
360
361	sblock.e2fs.e2fs_magic = E2FS_MAGIC;
362	sblock.e2fs.e2fs_state = E2FS_ISCLEAN;
363	sblock.e2fs.e2fs_beh = E2FS_BEH_DEFAULT;
364	sblock.e2fs.e2fs_minrev = 0;
365	sblock.e2fs.e2fs_lastfsck = tv.tv_sec;
366	sblock.e2fs.e2fs_fsckintv = EXT2_DEF_FSCKINTV;
367
368	/*
369	 * Maybe we can use E2FS_OS_FREEBSD here and it would be more proper,
370	 * but the purpose of this newfs_ext2fs(8) command is to provide
371	 * a filesystem which can be recognized by firmware on some
372	 * Linux based appliances that can load bootstrap files only from
373	 * (their native) ext2fs, and anyway we will (and should) try to
374	 * act like them as much as possible.
375	 *
376	 * Anyway, I hope that all newer such boxes will keep their support
377	 * for the "GOOD_OLD_REV" ext2fs.
378	 */
379	sblock.e2fs.e2fs_creator = E2FS_OS_LINUX;
380
381	if (Oflag == 0) {
382		sblock.e2fs.e2fs_rev = E2FS_REV0;
383		sblock.e2fs.e2fs_features_compat   = 0;
384		sblock.e2fs.e2fs_features_incompat = 0;
385		sblock.e2fs.e2fs_features_rocompat = 0;
386	} else {
387		sblock.e2fs.e2fs_rev = E2FS_REV1;
388		/*
389		 * e2fsprogs say "REV1" is "dynamic" so
390		 * it isn't quite a version and maybe it means
391		 * "extended from REV0 so check compat features."
392		 *
393		 * XXX: We don't have any native tool to activate
394		 *      the EXT2F_COMPAT_RESIZE feature and
395		 *      fsck_ext2fs(8) might not fix structures for it.
396		 */
397		sblock.e2fs.e2fs_features_compat   = EXT2F_COMPAT_RESIZE;
398		sblock.e2fs.e2fs_features_incompat = EXT2F_INCOMPAT_FTYPE;
399		sblock.e2fs.e2fs_features_rocompat =
400		    EXT2F_ROCOMPAT_SPARSESUPER | EXT2F_ROCOMPAT_LARGEFILE;
401	}
402
403	sblock.e2fs.e2fs_ruid = geteuid();
404	sblock.e2fs.e2fs_rgid = getegid();
405
406	sblock.e2fs.e2fs_first_ino = EXT2_FIRSTINO;
407	sblock.e2fs.e2fs_inode_size = inodesize;
408
409	/* e2fs_block_group_nr is set on writing superblock to each group */
410
411	uuid_create(&uuid, &uustat);
412	if (uustat != uuid_s_ok)
413		errx(EXIT_FAILURE, "Failed to generate uuid\n");
414	uuid_enc_le(sblock.e2fs.e2fs_uuid, &uuid);
415	if (volname != NULL) {
416		if (strlen(volname) > sizeof(sblock.e2fs.e2fs_vname))
417			errx(EXIT_FAILURE, "Volume name is too long");
418		strlcpy(sblock.e2fs.e2fs_vname, volname,
419		    sizeof(sblock.e2fs.e2fs_vname));
420	}
421
422	sblock.e2fs.e2fs_fsmnt[0] = '\0';
423	sblock.e2fs_fsmnt[0] = '\0';
424
425	sblock.e2fs.e2fs_algo = 0;		/* XXX unsupported? */
426	sblock.e2fs.e2fs_prealloc = 0;		/* XXX unsupported? */
427	sblock.e2fs.e2fs_dir_prealloc = 0;	/* XXX unsupported? */
428
429	/* calculate blocks for reserved group descriptors for resize */
430	sblock.e2fs.e2fs_reserved_ngdb = 0;
431	if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
432	    (sblock.e2fs.e2fs_features_compat & EXT2F_COMPAT_RESIZE) != 0) {
433		uint64_t target_blocks;
434		uint target_ncg, target_ngdb, reserved_ngdb;
435
436		/* reserve descriptors for size as 1024 times as current */
437		target_blocks =
438		    (sblock.e2fs.e2fs_bcount - sblock.e2fs.e2fs_first_dblock)
439		    * 1024ULL;
440		/* number of blocks must be in uint32_t */
441		if (target_blocks > UINT32_MAX)
442			target_blocks = UINT32_MAX;
443		target_ncg = howmany(target_blocks, sblock.e2fs.e2fs_bpg);
444		target_ngdb = howmany(sizeof(struct ext2_gd) * target_ncg,
445		    sblock.e2fs_bsize);
446		/*
447		 * Reserved group descriptor blocks are preserved as
448		 * the second level double indirect reference blocks in
449		 * the EXT2_RESIZEINO inode, so the maximum number of
450		 * the blocks is NINDIR(fs).
451		 * (see also descriptions in init_resizeino() function)
452		 *
453		 * We check a number including current e2fs_ngdb here
454		 * because they will be moved into reserved gdb on
455		 * possible future size shrink, though e2fsprogs don't
456		 * seem to care about it.
457		 */
458		if (target_ngdb > NINDIR(&sblock))
459			target_ngdb = NINDIR(&sblock);
460
461		reserved_ngdb = target_ngdb - sblock.e2fs_ngdb;
462
463		/* make sure reserved_ngdb fits in the last cg */
464		if (reserved_ngdb >= blocks_lastcg - cgoverhead(ncg - 1))
465			reserved_ngdb = blocks_lastcg - cgoverhead(ncg - 1);
466		if (reserved_ngdb == 0) {
467			/* if no space for reserved gdb, disable the feature */
468			sblock.e2fs.e2fs_features_compat &=
469			    ~EXT2F_COMPAT_RESIZE;
470		}
471		sblock.e2fs.e2fs_reserved_ngdb = reserved_ngdb;
472	}
473
474	/*
475	 * Initialize group descriptors
476	 */
477	gd = malloc(sblock.e2fs_ngdb * bsize);
478	if (gd == NULL)
479		errx(EXIT_FAILURE, "Can't allocate descriptors buffer");
480	memset(gd, 0, sblock.e2fs_ngdb * bsize);
481
482	fbcount = 0;
483	ficount = 0;
484	for (cylno = 0; cylno < ncg; cylno++) {
485		uint boffset;
486
487		boffset = cgbase(&sblock, cylno);
488		if (sblock.e2fs.e2fs_rev == E2FS_REV0 ||
489		    (sblock.e2fs.e2fs_features_rocompat &
490		     EXT2F_ROCOMPAT_SPARSESUPER) == 0 ||
491		    cg_has_sb(cylno)) {
492			boffset += NBLOCK_SUPERBLOCK + sblock.e2fs_ngdb;
493			if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
494			    (sblock.e2fs.e2fs_features_compat &
495			     EXT2F_COMPAT_RESIZE) != 0)
496				boffset += sblock.e2fs.e2fs_reserved_ngdb;
497		}
498		gd[cylno].ext2bgd_b_bitmap = boffset;
499		boffset += NBLOCK_BLOCK_BITMAP;
500		gd[cylno].ext2bgd_i_bitmap = boffset;
501		boffset += NBLOCK_INODE_BITMAP;
502		gd[cylno].ext2bgd_i_tables = boffset;
503		if (cylno == (ncg - 1))
504			gd[cylno].ext2bgd_nbfree =
505			    blocks_lastcg - cgoverhead(cylno);
506		else
507			gd[cylno].ext2bgd_nbfree =
508			    sblock.e2fs.e2fs_bpg - cgoverhead(cylno);
509		fbcount += gd[cylno].ext2bgd_nbfree;
510		gd[cylno].ext2bgd_nifree = sblock.e2fs.e2fs_ipg;
511		if (cylno == 0) {
512			/* take reserved inodes off nifree */
513			gd[cylno].ext2bgd_nifree -= EXT2_RESERVED_INODES;
514		}
515		ficount += gd[cylno].ext2bgd_nifree;
516		gd[cylno].ext2bgd_ndirs = 0;
517	}
518	sblock.e2fs.e2fs_fbcount = fbcount;
519	sblock.e2fs.e2fs_ficount = ficount;
520
521	/*
522	 * Dump out summary information about file system.
523	 */
524	if (verbosity > 0) {
525		printf("%s: %u.%1uMB (%" PRId64 " sectors) "
526		    "block size %u, fragment size %u\n",
527		    fsys,
528		    (uint)(((uint64_t)bcount * bsize) / (1024 * 1024)),
529		    (uint)((uint64_t)bcount * bsize -
530		    rounddown((uint64_t)bcount * bsize, 1024 * 1024))
531		    / 1024 / 100,
532		    fssize, bsize, fsize);
533		printf("\tusing %u block groups of %u.0MB, %u blks, "
534		    "%u inodes.\n",
535		    ncg, bsize * sblock.e2fs.e2fs_bpg / (1024 * 1024),
536		    sblock.e2fs.e2fs_bpg, sblock.e2fs.e2fs_ipg);
537	}
538
539	/*
540	 * allocate space for superblock and group descriptors
541	 */
542	iobufsize = (NBLOCK_SUPERBLOCK + sblock.e2fs_ngdb) * sblock.e2fs_bsize;
543	iobuf = mmap(0, iobufsize, PROT_READ|PROT_WRITE,
544	    MAP_ANON|MAP_PRIVATE, -1, 0);
545	if (iobuf == NULL)
546		errx(EXIT_FAILURE, "Cannot allocate I/O buffer\n");
547	memset(iobuf, 0, iobufsize);
548
549	/*
550	 * We now start writing to the filesystem
551	 */
552
553	if (!Nflag) {
554		static const uint pbsize[] = { 1024, 2048, 4096, 0 };
555		uint pblock, epblock;
556		/*
557		 * Validate the given file system size.
558		 * Verify that its last block can actually be accessed.
559		 * Convert to file system fragment sized units.
560		 */
561		if (fssize <= 0)
562			errx(EXIT_FAILURE, "Preposterous size %" PRId64 "\n",
563			    fssize);
564		wtfs(fssize - 1, sectorsize, iobuf);
565
566		/*
567		 * Ensure there is nothing that looks like a filesystem
568		 * superblock anywhere other than where ours will be.
569		 * If fsck_ext2fs finds the wrong one all hell breaks loose!
570		 *
571		 * XXX: needs to check how fsck_ext2fs programs even
572		 *      on other OSes determine alternate superblocks
573		 */
574		for (i = 0; pbsize[i] != 0; i++) {
575			epblock = (uint64_t)bcount * bsize / pbsize[i];
576			for (pblock = ((pbsize[i] == SBSIZE) ? 1 : 0);
577			    pblock < epblock;
578			    pblock += pbsize[i] * NBBY /* bpg */)
579				zap_old_sblock((daddr_t)pblock *
580				    pbsize[i] / sectorsize);
581		}
582	}
583
584	if (verbosity >= 3)
585		printf("super-block backups (for fsck_ext2fs -b #) at:\n");
586	/* If we are printing more than one line of numbers, line up columns */
587	fld_width = verbosity < 4 ? 1 : snprintf(NULL, 0, "%" PRIu64,
588	    (uint64_t)cgbase(&sblock, ncg - 1));
589	/* Get terminal width */
590	if (ioctl(fileno(stdout), TIOCGWINSZ, &winsize) == 0)
591		max_cols = winsize.ws_col;
592	else
593		max_cols = 80;
594	if (Nflag && verbosity == 3)
595		/* Leave space to add " ..." after one row of numbers */
596		max_cols -= 4;
597#define BASE 0x10000	/* For some fixed-point maths */
598	col = 0;
599	delta = verbosity > 2 ? 0 : max_cols * BASE / ncg;
600	for (cylno = 0; cylno < ncg; cylno++) {
601		fflush(stdout);
602		initcg(cylno);
603		if (verbosity < 2)
604			continue;
605		/* the first one is a master, not backup */
606		if (cylno == 0)
607			continue;
608		/* skip if this cylinder doesn't have a backup */
609		if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
610		    (sblock.e2fs.e2fs_features_rocompat &
611		     EXT2F_ROCOMPAT_SPARSESUPER) != 0 &&
612		    cg_has_sb(cylno) == 0)
613			continue;
614
615		if (delta > 0) {
616			if (Nflag)
617				/* No point doing dots for -N */
618				break;
619			/* Print dots scaled to end near RH margin */
620			for (col += delta; col > BASE; col -= BASE)
621				printf(".");
622			continue;
623		}
624		/* Print superblock numbers */
625		len = printf(" %*" PRIu64 "," + !col, fld_width,
626		    (uint64_t)cgbase(&sblock, cylno));
627		col += len;
628		if (col + len < max_cols)
629			/* Next number fits */
630			continue;
631		/* Next number won't fit, need a newline */
632		if (verbosity <= 3) {
633			/* Print dots for subsequent cylinder groups */
634			delta = sblock.e2fs_ncg - cylno - 1;
635			if (delta != 0) {
636				if (Nflag) {
637					printf(" ...");
638					break;
639				}
640				delta = max_cols * BASE / delta;
641			}
642		}
643		col = 0;
644		printf("\n");
645	}
646#undef BASE
647	if (col > 0)
648		printf("\n");
649	if (Nflag)
650		return;
651
652	/*
653	 * Now construct the initial file system,
654	 */
655	if (fsinit(&tv) == 0)
656		errx(EXIT_FAILURE, "Error making filesystem");
657	/*
658	 * Write out the superblock and group descriptors
659	 */
660	sblock.e2fs.e2fs_block_group_nr = 0;
661	sboff = 0;
662	if (cgbase(&sblock, 0) == 0) {
663		/*
664		 * If the first block contains the boot block sectors,
665		 * (i.e. in case of sblock.e2fs.e2fs_bsize > BBSIZE)
666		 * we have to preserve data in it.
667		 */
668		sboff = SBOFF;
669	}
670	e2fs_sbsave(&sblock.e2fs, (struct ext2fs *)(iobuf + sboff));
671	e2fs_cgsave(gd, (struct ext2_gd *)(iobuf + sblock.e2fs_bsize),
672	   sizeof(struct ext2_gd) * sblock.e2fs_ncg);
673	wtfs(fsbtodb(&sblock, cgbase(&sblock, 0)) + sboff / sectorsize,
674	    iobufsize - sboff, iobuf + sboff);
675
676	munmap(iobuf, iobufsize);
677}
678
679/*
680 * Initialize a cylinder (block) group.
681 */
682void
683initcg(uint cylno)
684{
685	uint nblcg, i, j, sboff;
686	struct ext2fs_dinode *dp;
687
688	/*
689	 * Make a copy of the superblock and group descriptors.
690	 */
691	if (sblock.e2fs.e2fs_rev == E2FS_REV0 ||
692	    (sblock.e2fs.e2fs_features_rocompat &
693	     EXT2F_ROCOMPAT_SPARSESUPER) == 0 ||
694	    cg_has_sb(cylno)) {
695		sblock.e2fs.e2fs_block_group_nr = cylno;
696		sboff = 0;
697		if (cgbase(&sblock, cylno) == 0) {
698			/* preserve data in bootblock in cg0 */
699			sboff = SBOFF;
700		}
701		e2fs_sbsave(&sblock.e2fs, (struct ext2fs *)(iobuf + sboff));
702		e2fs_cgsave(gd, (struct ext2_gd *)(iobuf +
703		    sblock.e2fs_bsize * NBLOCK_SUPERBLOCK),
704		    sizeof(struct ext2_gd) * sblock.e2fs_ncg);
705		/* write superblock and group descriptor backups */
706		wtfs(fsbtodb(&sblock, cgbase(&sblock, cylno)) +
707		    sboff / sectorsize, iobufsize - sboff, iobuf + sboff);
708	}
709
710	/*
711	 * Initialize block bitmap.
712	 */
713	memset(buf, 0, sblock.e2fs_bsize);
714	if (cylno == (sblock.e2fs_ncg - 1)) {
715		/* The last group could have less blocks than e2fs_bpg. */
716		nblcg = sblock.e2fs.e2fs_bcount -
717		    cgbase(&sblock, sblock.e2fs_ncg - 1);
718		for (i = nblcg; i < roundup(nblcg, NBBY); i++)
719			setbit(buf, i);
720		memset(&buf[i / NBBY], ~0U, sblock.e2fs.e2fs_bpg - i);
721	}
722	/* set overhead (superblock, group descriptor etc.) blocks used */
723	for (i = 0; i < cgoverhead(cylno) / NBBY; i++)
724		buf[i] = ~0;
725	i = i * NBBY;
726	for (; i < cgoverhead(cylno); i++)
727		setbit(buf, i);
728	wtfs(fsbtodb(&sblock, gd[cylno].ext2bgd_b_bitmap), sblock.e2fs_bsize,
729	    buf);
730
731	/*
732	 * Initialize inode bitmap.
733	 *
734	 *  Assume e2fs_ipg is a multiple of NBBY since
735	 *  it's a multiple of e2fs_ipb (as we did above).
736	 *  Note even (possibly smaller) the last group has the same e2fs_ipg.
737	 */
738	i = sblock.e2fs.e2fs_ipg / NBBY;
739	memset(buf, 0, i);
740	memset(buf + i, ~0U, sblock.e2fs_bsize - i);
741	if (cylno == 0) {
742		/* mark reserved inodes */
743		for (i = 1; i < EXT2_FIRSTINO; i++)
744			setbit(buf, EXT2_INO_INDEX(i));
745	}
746	wtfs(fsbtodb(&sblock, gd[cylno].ext2bgd_i_bitmap), sblock.e2fs_bsize,
747	    buf);
748
749	/*
750	 * Initialize inode tables.
751	 *
752	 *  Just initialize generation numbers for NFS security.
753	 *  XXX: sys/ufs/ext2fs/ext2fs_alloc.c:ext2fs_valloc() seems
754	 *       to override these generated numbers.
755	 */
756	memset(buf, 0, sblock.e2fs_bsize);
757	for (i = 0; i < sblock.e2fs_itpg; i++) {
758		for (j = 0; j < sblock.e2fs_ipb; j++) {
759			dp = (struct ext2fs_dinode *)(buf + inodesize * j);
760			/* h2fs32() just for consistency */
761			dp->e2di_gen = h2fs32(arc4random());
762		}
763		wtfs(fsbtodb(&sblock, gd[cylno].ext2bgd_i_tables + i),
764		    sblock.e2fs_bsize, buf);
765	}
766}
767
768/*
769 * Zap possible lingering old superblock data
770 */
771static void
772zap_old_sblock(daddr_t sec)
773{
774	static daddr_t cg0_data;
775	uint32_t oldfs[SBSIZE / sizeof(uint32_t)];
776	static const struct fsm {
777		uint32_t offset;
778		uint32_t magic;
779		uint32_t mask;
780	} fs_magics[] = {
781		{offsetof(struct ext2fs, e2fs_magic) / 4, E2FS_MAGIC, 0xffff},
782		{offsetof(struct ext2fs, e2fs_magic) / 4,
783		    E2FS_MAGIC << 16, 0xffff0000},
784		{14, 0xef530000, 0xffff0000},	/* EXT2FS (big) */
785		{0x55c / 4, 0x00011954, ~0U},	/* FS_UFS1_MAGIC */
786		{0x55c / 4, 0x19540119, ~0U},	/* FS_UFS2_MAGIC */
787		{0, 0x70162, ~0U},		/* LFS_MAGIC */
788		{.offset = ~0U},
789	};
790	const struct fsm *fsm;
791
792	if (Nflag)
793		return;
794
795	/* don't override data before superblock */
796	if (sec < SBOFF / sectorsize)
797		return;
798
799	if (cg0_data == 0) {
800		cg0_data =
801		    ((daddr_t)sblock.e2fs.e2fs_first_dblock + cgoverhead(0)) *
802		    sblock.e2fs_bsize / sectorsize;
803	}
804
805	/* Ignore anything that is beyond our filesystem */
806	if (sec >= fssize)
807		return;
808	/* Zero anything inside our filesystem... */
809	if (sec >= sblock.e2fs.e2fs_first_dblock * bsize / sectorsize) {
810		/* ...unless we will write that area anyway */
811		if (sec >= cg0_data)
812			/* assume iobuf is zero'ed here */
813			wtfs(sec, roundup(SBSIZE, sectorsize), iobuf);
814		return;
815	}
816
817	/*
818	 * The sector might contain boot code, so we must validate it
819	 *
820	 * XXX: ext2fs won't preserve data after SBOFF,
821	 *      but first_dblock could have a different value.
822	 */
823	rdfs(sec, sizeof(oldfs), &oldfs);
824	for (fsm = fs_magics;; fsm++) {
825		uint32_t v;
826		if (fsm->mask == 0)
827			return;
828		v = oldfs[fsm->offset];
829		if ((v & fsm->mask) == fsm->magic ||
830		    (bswap32(v) & fsm->mask) == fsm->magic)
831			break;
832	}
833
834	/* Just zap the magic number */
835	oldfs[fsm->offset] = 0;
836	wtfs(sec, sizeof(oldfs), &oldfs);
837}
838
839/*
840 * uint cgoverhead(uint c)
841 *
842 * 	Return a number of reserved blocks on the specified group.
843 * 	XXX: should be shared with src/sbin/fsck_ext2fs/setup.c
844 */
845uint
846cgoverhead(uint c)
847{
848	uint overh;
849
850	overh = NBLOCK_BLOCK_BITMAP + NBLOCK_INODE_BITMAP + sblock.e2fs_itpg;
851
852	if (sblock.e2fs.e2fs_rev == E2FS_REV0 ||
853	    (sblock.e2fs.e2fs_features_rocompat &
854	     EXT2F_ROCOMPAT_SPARSESUPER) == 0 ||
855	    cg_has_sb(c) != 0) {
856		overh += NBLOCK_SUPERBLOCK + sblock.e2fs_ngdb;
857
858		if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
859		    (sblock.e2fs.e2fs_features_compat &
860		     EXT2F_COMPAT_RESIZE) != 0)
861			overh += sblock.e2fs.e2fs_reserved_ngdb;
862	}
863
864	return overh;
865}
866
867/*
868 * Initialize the file system
869 */
870
871#define LOSTDIR		/* e2fsck complains if there is no lost+found */
872
873#define	PREDEFDIR	2
874
875#ifdef LOSTDIR
876#define	PREDEFROOTDIR	(PREDEFDIR + 1)
877#else
878#define	PREDEFROOTDIR	PREDEFDIR
879#endif
880
881struct ext2fs_direct root_dir[] = {
882	{ EXT2_ROOTINO, 0, 1, 0, "." },
883	{ EXT2_ROOTINO, 0, 2, 0, ".." },
884#ifdef LOSTDIR
885	{ EXT2_LOSTFOUNDINO, 0, 10, 0, "lost+found" },
886#endif
887};
888
889#ifdef LOSTDIR
890struct ext2fs_direct lost_found_dir[] = {
891	{ EXT2_LOSTFOUNDINO, 0, 1, 0, "." },
892	{ EXT2_ROOTINO, 0, 2, 0, ".." },
893};
894struct ext2fs_direct pad_dir = { 0, sizeof(struct ext2fs_direct), 0, 0, "" };
895#endif
896
897int
898fsinit(const struct timeval *tv)
899{
900	struct ext2fs_dinode node;
901#ifdef LOSTDIR
902	uint i, nblks_lostfound, blk;
903#endif
904
905	/*
906	 * Initialize the inode for the resizefs feature
907	 */
908	if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
909	    (sblock.e2fs.e2fs_features_compat & EXT2F_COMPAT_RESIZE) != 0)
910		init_resizeino(tv);
911
912	/*
913	 * Initialize the node
914	 */
915
916#ifdef LOSTDIR
917	/*
918	 * Create the lost+found directory
919	 */
920	if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
921	    sblock.e2fs.e2fs_features_incompat & EXT2F_INCOMPAT_FTYPE) {
922		lost_found_dir[0].e2d_type = EXT2_FT_DIR;
923		lost_found_dir[1].e2d_type = EXT2_FT_DIR;
924	}
925	(void)makedir(lost_found_dir, __arraycount(lost_found_dir));
926
927	/* prepare a bit large directory for preserved files */
928	nblks_lostfound = EXT2_LOSTFOUNDSIZE / sblock.e2fs_bsize;
929	/* ...but only with direct blocks */
930	if (nblks_lostfound > NDADDR)
931		nblks_lostfound = NDADDR;
932
933	memset(&node, 0, sizeof(node));
934	node.e2di_mode = EXT2_IFDIR | EXT2_LOSTFOUNDUMASK;
935	node.e2di_uid = geteuid();
936	node.e2di_size = sblock.e2fs_bsize * nblks_lostfound;
937	node.e2di_atime = tv->tv_sec;
938	node.e2di_ctime = tv->tv_sec;
939	node.e2di_mtime = tv->tv_sec;
940	node.e2di_gid = getegid();
941	node.e2di_nlink = PREDEFDIR;
942	/* e2di_nblock is a number of disk blocks, not ext2fs blocks */
943	node.e2di_nblock = fsbtodb(&sblock, nblks_lostfound);
944	node.e2di_blocks[0] = alloc(sblock.e2fs_bsize, node.e2di_mode);
945	if (node.e2di_blocks[0] == 0) {
946		printf("%s: can't allocate block for lost+found\n", __func__);
947		return 0;
948	}
949	for (i = 1; i < nblks_lostfound; i++) {
950		blk = alloc(sblock.e2fs_bsize, 0);
951		if (blk == 0) {
952			printf("%s: can't allocate blocks for lost+found\n",
953			    __func__);
954			return 0;
955		}
956		node.e2di_blocks[i] = blk;
957	}
958	wtfs(fsbtodb(&sblock, node.e2di_blocks[0]), sblock.e2fs_bsize, buf);
959	pad_dir.e2d_reclen = sblock.e2fs_bsize;
960	for (i = 1; i < nblks_lostfound; i++) {
961		memset(buf, 0, sblock.e2fs_bsize);
962		copy_dir(&pad_dir, (struct ext2fs_direct *)buf);
963		wtfs(fsbtodb(&sblock, node.e2di_blocks[i]), sblock.e2fs_bsize,
964		    buf);
965	}
966	iput(&node, EXT2_LOSTFOUNDINO);
967#endif
968	/*
969	 * create the root directory
970	 */
971	memset(&node, 0, sizeof(node));
972	if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
973	    sblock.e2fs.e2fs_features_incompat & EXT2F_INCOMPAT_FTYPE) {
974		root_dir[0].e2d_type = EXT2_FT_DIR;
975		root_dir[1].e2d_type = EXT2_FT_DIR;
976#ifdef LOSTDIR
977		root_dir[2].e2d_type = EXT2_FT_DIR;
978#endif
979	}
980	node.e2di_mode = EXT2_IFDIR | EXT2_UMASK;
981	node.e2di_uid = geteuid();
982	node.e2di_size = makedir(root_dir, __arraycount(root_dir));
983	node.e2di_atime = tv->tv_sec;
984	node.e2di_ctime = tv->tv_sec;
985	node.e2di_mtime = tv->tv_sec;
986	node.e2di_gid = getegid();
987	node.e2di_nlink = PREDEFROOTDIR;
988	/* e2di_nblock is a number of disk block, not ext2fs block */
989	node.e2di_nblock = fsbtodb(&sblock, 1);
990	node.e2di_blocks[0] = alloc(node.e2di_size, node.e2di_mode);
991	if (node.e2di_blocks[0] == 0) {
992		printf("%s: can't allocate block for root dir\n", __func__);
993		return 0;
994	}
995	wtfs(fsbtodb(&sblock, node.e2di_blocks[0]), sblock.e2fs_bsize, buf);
996	iput(&node, EXT2_ROOTINO);
997	return 1;
998}
999
1000/*
1001 * Construct a set of directory entries in "buf".
1002 * return size of directory.
1003 */
1004int
1005makedir(struct ext2fs_direct *protodir, int entries)
1006{
1007	uint8_t *cp;
1008	uint i, spcleft;
1009	uint dirblksiz;
1010
1011	dirblksiz = sblock.e2fs_bsize;
1012	memset(buf, 0, dirblksiz);
1013	spcleft = dirblksiz;
1014	for (cp = buf, i = 0; i < entries - 1; i++) {
1015		protodir[i].e2d_reclen = EXT2FS_DIRSIZ(protodir[i].e2d_namlen);
1016		copy_dir(&protodir[i], (struct ext2fs_direct *)cp);
1017		cp += protodir[i].e2d_reclen;
1018		spcleft -= protodir[i].e2d_reclen;
1019	}
1020	protodir[i].e2d_reclen = spcleft;
1021	copy_dir(&protodir[i], (struct ext2fs_direct *)cp);
1022	return dirblksiz;
1023}
1024
1025/*
1026 * Copy a direntry to a buffer, in fs byte order
1027 */
1028static void
1029copy_dir(struct ext2fs_direct *dir, struct ext2fs_direct *dbuf)
1030{
1031
1032	memcpy(dbuf, dir, EXT2FS_DIRSIZ(dir->e2d_namlen));
1033	dbuf->e2d_ino = h2fs32(dir->e2d_ino);
1034	dbuf->e2d_reclen = h2fs16(dir->e2d_reclen);
1035}
1036
1037/*
1038 * void init_resizeino(const struct timeval *tv);
1039 *
1040 *	Initialize the EXT2_RESEIZE_INO inode to preserve
1041 *	reserved group descriptor blocks for future growth of this ext2fs.
1042 */
1043void
1044init_resizeino(const struct timeval *tv)
1045{
1046	struct ext2fs_dinode node;
1047	uint64_t isize;
1048	uint32_t *dindir_block, *reserved_gdb;
1049	uint nblock, i, cylno, n;
1050
1051	memset(&node, 0, sizeof(node));
1052
1053	/*
1054	 * Note this function only prepares required structures for
1055	 * future resize. It's a quite different work to implement
1056	 * a utility like resize_ext2fs(8) which handles actual
1057	 * resize ops even on offline.
1058	 *
1059	 * Anyway, I'm not sure if there is any documentation about
1060	 * this resize ext2fs feature and related data structures,
1061	 * and I've written this function based on things what I see
1062	 * on some existing implementation and real file system data
1063	 * created by existing tools. To be honest, they are not
1064	 * so easy to read, so I will try to implement it here without
1065	 * any dumb optimization for people who would eventually
1066	 * work on "yet another wheel" like resize_ext2fs(8).
1067	 */
1068
1069	/*
1070	 * I'm not sure what type is appropriate for this inode.
1071	 * The release notes of e2fsprogs says they changed e2fsck to allow
1072	 * IFREG for RESIZEINO since a certain resize tool used it. Hmm.
1073	 */
1074	node.e2di_mode = EXT2_IFREG | EXT2_RESIZEINOUMASK;
1075	node.e2di_uid = geteuid();
1076	node.e2di_atime = tv->tv_sec;
1077	node.e2di_ctime = tv->tv_sec;
1078	node.e2di_mtime = tv->tv_sec;
1079	node.e2di_gid = getegid();
1080	node.e2di_nlink = 1;
1081
1082	/*
1083	 * To preserve the reserved group descriptor blocks,
1084	 * EXT2_RESIZEINO uses only double indirect reference
1085	 * blocks in its inode entries.
1086	 *
1087	 * All entries for direct, single indirect and triple
1088	 * indirect references are left zero'ed. Maybe it's safe
1089	 * because no write operation will happen with this inode.
1090	 *
1091	 * We have to allocate a block for the first level double
1092	 * indirect reference block. Indexes of inode entries in
1093	 * this first level dindirect block are corresponding to
1094	 * indexes of group descriptors including both used (e2fs_ngdb)
1095	 * and reserved (e2fs_reserved_ngdb) group descriptor blocks.
1096	 *
1097	 * Inode entries of indexes for used (e2fs_ngdb) descriptors are
1098	 * left zero'ed. Entries for reserved (e2fs_reserved_ngdb) ones
1099	 * have block numbers of actual reserved group descriptors
1100	 * allocated at block group zero. This means e2fs_reserved_ngdb
1101	 * blocks are reserved as the second level dindirect reference
1102	 * blocks, and they actually contain block numbers of indirect
1103	 * references. It may be safe since they don't have to keep any
1104	 * data yet.
1105	 *
1106	 * Each these second dindirect blocks (i.e. reserved group
1107	 * descriptor blocks in the first block group) should have
1108	 * block numbers of its backups in all other block groups.
1109	 * I.e. reserved_ngdb[0] block in block group 0 contains block
1110	 * numbers of resreved_ngdb[0] from group 1 through (e2fs_ncg - 1).
1111	 * The number of backups can be determined by the
1112	 * EXT2_ROCOMPAT_SPARSESUPER feature and cg_has_sb() macro
1113	 * as done in the above initcg() function.
1114	 */
1115
1116	/* set e2di_size which occupies whole blocks through DINDIR blocks */
1117	isize = (uint64_t)sblock.e2fs_bsize * NDADDR +
1118	    (uint64_t)sblock.e2fs_bsize * NINDIR(&sblock) +
1119	    (uint64_t)sblock.e2fs_bsize * NINDIR(&sblock) * NINDIR(&sblock);
1120	if (isize > UINT32_MAX &&
1121	    (sblock.e2fs.e2fs_features_rocompat &
1122	     EXT2F_ROCOMPAT_LARGEFILE) == 0) {
1123		/* XXX should enable it here and update all backups? */
1124		errx(EXIT_FAILURE, "%s: large_file rocompat feature is "
1125		    "required to enable resize feature for this filesystem\n",
1126		    __func__);
1127	}
1128	/* upper 32bit is stored into e2di_dacl on REV1 feature */
1129	node.e2di_size = isize & UINT32_MAX;
1130	node.e2di_dacl = isize >> 32;
1131
1132#define SINGLE	0	/* index of single indirect block */
1133#define DOUBLE	1	/* index of double indirect block */
1134#define TRIPLE	2	/* index of triple indirect block */
1135
1136	/* zero out entries for direct references */
1137	for (i = 0; i < NDADDR; i++)
1138		node.e2di_blocks[i] = 0;
1139	/* also zero out entries for single and triple indirect references */
1140	node.e2di_blocks[NDADDR + SINGLE] = 0;
1141	node.e2di_blocks[NDADDR + TRIPLE] = 0;
1142
1143	/* allocate a block for the first level double indirect reference */
1144	node.e2di_blocks[NDADDR + DOUBLE] =
1145	    alloc(sblock.e2fs_bsize, node.e2di_mode);
1146	if (node.e2di_blocks[NDADDR + DOUBLE] == 0)
1147		errx(EXIT_FAILURE, "%s: Can't allocate a dindirect block",
1148		    __func__);
1149
1150	/* account this first block */
1151	nblock = fsbtodb(&sblock, 1);
1152
1153	/* allocate buffer to set data in the dindirect block */
1154	dindir_block = malloc(sblock.e2fs_bsize);
1155	if (dindir_block == NULL)
1156		errx(EXIT_FAILURE,
1157		    "%s: Can't allocate buffer for a dindirect block",
1158		    __func__);
1159
1160	/* allocate buffer to set data in the group descriptor blocks */
1161	reserved_gdb = malloc(sblock.e2fs_bsize);
1162	if (reserved_gdb == NULL)
1163		errx(EXIT_FAILURE,
1164		    "%s: Can't allocate buffer for group descriptor blocks",
1165		    __func__);
1166
1167	/*
1168	 * Setup block entries in the first level dindirect blocks
1169	 */
1170	for (i = 0; i < sblock.e2fs_ngdb; i++) {
1171		/* no need to handle used group descriptor blocks */
1172		dindir_block[i] = 0;
1173	}
1174	for (; i < sblock.e2fs_ngdb + sblock.e2fs.e2fs_reserved_ngdb; i++) {
1175		/*
1176		 * point reserved group descriptor block in the first
1177		 * (i.e. master) block group
1178		 *
1179		 * XXX: e2fsprogs seem to use "(i % NINDIR(&sblock))" here
1180		 *      to store maximum NINDIR(&sblock) reserved gdbs.
1181		 *      I'm not sure what will be done on future filesystem
1182		 *      shrink in that case on their way.
1183		 */
1184		if (i >= NINDIR(&sblock))
1185			errx(EXIT_FAILURE, "%s: too many reserved "
1186			    "group descriptors (%u) for resize inode",
1187			    __func__, sblock.e2fs.e2fs_reserved_ngdb);
1188		dindir_block[i] =
1189		    h2fs32(cgbase(&sblock, 0) + NBLOCK_SUPERBLOCK + i);
1190
1191		/*
1192		 * Setup block entries in the second dindirect blocks
1193		 * (which are primary reserved group descriptor blocks)
1194		 * to point their backups.
1195		 */
1196		for (n = 0, cylno = 1; cylno < sblock.e2fs_ncg; cylno++) {
1197			/* skip block groups without backup */
1198			if ((sblock.e2fs.e2fs_features_rocompat &
1199			     EXT2F_ROCOMPAT_SPARSESUPER) != 0 &&
1200			    cg_has_sb(cylno) == 0)
1201				continue;
1202
1203			if (n >= NINDIR(&sblock))
1204				errx(EXIT_FAILURE, "%s: too many block groups "
1205				    "for the resize feature", __func__);
1206			/*
1207			 * These blocks are already reserved in
1208			 * initcg() so no need to use alloc() here.
1209			 */
1210			reserved_gdb[n++] = h2fs32(cgbase(&sblock, cylno) +
1211			    NBLOCK_SUPERBLOCK + i);
1212			nblock += fsbtodb(&sblock, 1);
1213		}
1214		for (; n < NINDIR(&sblock); n++)
1215			reserved_gdb[n] = 0;
1216
1217		/* write group descriptor block as the second dindirect refs */
1218		wtfs(fsbtodb(&sblock, fs2h32(dindir_block[i])),
1219		    sblock.e2fs_bsize, reserved_gdb);
1220		nblock += fsbtodb(&sblock, 1);
1221	}
1222	for (; i < NINDIR(&sblock); i++) {
1223		/* leave trailing entries unallocated */
1224		dindir_block[i] = 0;
1225	}
1226	free(reserved_gdb);
1227
1228	/* finally write the first level dindirect block */
1229	wtfs(fsbtodb(&sblock, node.e2di_blocks[NDADDR + DOUBLE]),
1230	    sblock.e2fs_bsize, dindir_block);
1231	free(dindir_block);
1232
1233	node.e2di_nblock = nblock;
1234	iput(&node, EXT2_RESIZEINO);
1235}
1236
1237/*
1238 * uint32_t alloc(uint32_t size, uint16_t mode)
1239 *
1240 *	Allocate a block (from cylinder group 0)
1241 *	Reference: src/sys/ufs/ext2fs/ext2fs_alloc.c:ext2fs_alloccg()
1242 */
1243uint32_t
1244alloc(uint32_t size, uint16_t mode)
1245{
1246	uint32_t loc, bno;
1247	uint8_t *bbp;
1248	uint len, map, i;
1249
1250	if (gd[0].ext2bgd_nbfree == 0)
1251		return 0;
1252
1253	if (size > sblock.e2fs_bsize)
1254		return 0;
1255
1256	bbp = malloc(sblock.e2fs_bsize);
1257	if (bbp == NULL)
1258		return 0;
1259	rdfs(fsbtodb(&sblock, gd[0].ext2bgd_b_bitmap), sblock.e2fs_bsize, bbp);
1260
1261	/* XXX: kernel uses e2fs_fpg here */
1262	len = sblock.e2fs.e2fs_bpg / NBBY;
1263
1264#if 0	/* no need block allocation for root or lost+found dir */
1265	for (loc = 0; loc < len; loc++) {
1266		if (bbp[loc] == 0) {
1267			bno = loc * NBBY;
1268			goto gotit;
1269		}
1270	}
1271#endif
1272
1273	loc = skpc(~0U, len, bbp);
1274	if (loc == 0)
1275		return 0;
1276	loc = len - loc;
1277	map = bbp[loc];
1278	bno = loc * NBBY;
1279	for (i = 0; i < NBBY; i++, bno++) {
1280		if ((map & (1 << i)) == 0)
1281			goto gotit;
1282	}
1283	return 0;
1284
1285 gotit:
1286	if (isset(bbp, bno))
1287		errx(EXIT_FAILURE, "%s: inconsistent bitmap\n", __func__);
1288
1289	setbit(bbp, bno);
1290	wtfs(fsbtodb(&sblock, gd[0].ext2bgd_b_bitmap), sblock.e2fs_bsize, bbp);
1291	free(bbp);
1292	/* XXX: modified group descriptors won't be written into backups */
1293	gd[0].ext2bgd_nbfree--;
1294	if ((mode & EXT2_IFDIR) != 0)
1295		gd[0].ext2bgd_ndirs++;
1296	sblock.e2fs.e2fs_fbcount--;
1297
1298	return sblock.e2fs.e2fs_first_dblock + bno;
1299}
1300
1301/*
1302 * void iput(struct ext2fs_dinode *ip, ino_t ino)
1303 *
1304 *	Put an inode entry into the corresponding table.
1305 */
1306static void
1307iput(struct ext2fs_dinode *ip, ino_t ino)
1308{
1309	daddr_t d;
1310	uint c, i;
1311	struct ext2fs_dinode *dp;
1312	uint8_t *bp;
1313
1314	bp = malloc(sblock.e2fs_bsize);
1315	if (bp == NULL)
1316		errx(EXIT_FAILURE, "%s: can't allocate buffer for inode\n",
1317		    __func__);
1318
1319	/*
1320	 * Reserved inodes are allocated and accounted in initcg()
1321	 * so skip checks of the bitmap and allocation for them.
1322	 */
1323	if (ino >= EXT2_FIRSTINO) {
1324		c = ino_to_cg(&sblock, ino);
1325
1326		/* sanity check */
1327		if (gd[c].ext2bgd_nifree == 0)
1328			errx(EXIT_FAILURE,
1329			    "%s: no free inode %" PRIu64 " in block group %u\n",
1330			    __func__, (uint64_t)ino, c);
1331
1332		/* update inode bitmap */
1333		rdfs(fsbtodb(&sblock, gd[0].ext2bgd_i_bitmap),
1334		    sblock.e2fs_bsize, bp);
1335
1336		/* more sanity */
1337		if (isset(bp, EXT2_INO_INDEX(ino)))
1338			errx(EXIT_FAILURE, "%s: inode %" PRIu64
1339			    " already in use\n", __func__, (uint64_t)ino);
1340		setbit(bp, EXT2_INO_INDEX(ino));
1341		wtfs(fsbtodb(&sblock, gd[0].ext2bgd_i_bitmap),
1342		    sblock.e2fs_bsize, bp);
1343		gd[c].ext2bgd_nifree--;
1344		sblock.e2fs.e2fs_ficount--;
1345	}
1346
1347	if (ino >= sblock.e2fs.e2fs_ipg * sblock.e2fs_ncg)
1348		errx(EXIT_FAILURE, "%s: inode value out of range (%" PRIu64
1349		    ").\n", __func__, (uint64_t)ino);
1350
1351	/* update an inode entry in the table */
1352	d = fsbtodb(&sblock, ino_to_fsba(&sblock, ino));
1353	rdfs(d, sblock.e2fs_bsize, bp);
1354
1355	dp = (struct ext2fs_dinode *)(bp +
1356	    inodesize * ino_to_fsbo(&sblock, ino));
1357	e2fs_isave(ip, dp);
1358	/* e2fs_i_bswap() doesn't swap e2di_blocks addrs */
1359	if ((ip->e2di_mode & EXT2_IFMT) != EXT2_IFLNK) {
1360		for (i = 0; i < NDADDR + NIADDR; i++)
1361			dp->e2di_blocks[i] = h2fs32(ip->e2di_blocks[i]);
1362	}
1363	/* h2fs32() just for consistency */
1364	dp->e2di_gen = h2fs32(arc4random());
1365
1366	wtfs(d, sblock.e2fs_bsize, bp);
1367	free(bp);
1368}
1369
1370/*
1371 * Read a block from the file system
1372 */
1373void
1374rdfs(daddr_t bno, int size, void *bf)
1375{
1376	int n;
1377	off_t offset;
1378
1379	offset = bno;
1380	n = pread(fsi, bf, size, offset * sectorsize);
1381	if (n != size)
1382		err(EXIT_FAILURE, "%s: read error for sector %" PRId64,
1383		    __func__, (int64_t)bno);
1384}
1385
1386/*
1387 * Write a block to the file system
1388 */
1389void
1390wtfs(daddr_t bno, int size, void *bf)
1391{
1392	int n;
1393	off_t offset;
1394
1395	if (Nflag)
1396		return;
1397	offset = bno;
1398	n = pwrite(fso, bf, size, offset * sectorsize);
1399	if (n != size)
1400		err(EXIT_FAILURE, "%s: write error for sector %" PRId64,
1401		    __func__, (int64_t)bno);
1402}
1403
1404int
1405ilog2(uint val)
1406{
1407
1408	if (val == 0 || !powerof2(val))
1409		errx(EXIT_FAILURE, "%s: %u is not a power of 2\n",
1410		    __func__, val);
1411
1412	return ffs(val) - 1;
1413}
1414
1415/*
1416 * int skpc(int mask, size_t size, uint8_t *cp)
1417 *
1418 *	Locate an unsigned character of value mask inside cp[].
1419 * 	(from src/sys/lib/libkern/skpc.c)
1420 */
1421int
1422skpc(int mask, size_t size, uint8_t *cp)
1423{
1424	uint8_t *end;
1425
1426	end = &cp[size];
1427	while (cp < end && *cp == (uint8_t)mask)
1428		cp++;
1429
1430	return end - cp;
1431}
1432