1/*	$NetBSD: mke2fs.c,v 1.27 2024/02/22 14:11:52 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 *		https://e2fsprogs.sourceforge.net/ext2.html
92 *	- Design and Implementation of the Second Extended Filesystem
93 *		https://e2fsprogs.sourceforge.net/ext2intro.html
94 *	- Linux Documentation "The Second Extended Filesystem"
95 *		https://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 1.27 2024/02/22 14:11:52 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(int);
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",
206		    bsize);
207	}
208	if (!powerof2(fsize)) {
209		errx(EXIT_FAILURE,
210		    "fragment size must be a power of 2, not %u",
211		    fsize);
212	}
213	if (fsize < sectorsize) {
214		errx(EXIT_FAILURE,
215		    "fragment size %u is too small, minimum is %u",
216		    fsize, sectorsize);
217	}
218	if (bsize < MINBSIZE) {
219		errx(EXIT_FAILURE,
220		    "block size %u is too small, minimum is %u",
221		    bsize, MINBSIZE);
222	}
223	if (bsize > EXT2_MAXBSIZE) {
224		errx(EXIT_FAILURE,
225		    "block size %u is too large, maximum is %u",
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)",
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", 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 = EXT2_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, fssize, minfssize);
280
281	bcount = EXT2_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");
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 EXT2_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 > EXT2_NINDIR(&sblock))
459			target_ngdb = EXT2_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 = h2fs32(boffset);
499		boffset += NBLOCK_BLOCK_BITMAP;
500		gd[cylno].ext2bgd_i_bitmap = h2fs32(boffset);
501		boffset += NBLOCK_INODE_BITMAP;
502		gd[cylno].ext2bgd_i_tables = h2fs32(boffset);
503		if (cylno == (ncg - 1))
504			gd[cylno].ext2bgd_nbfree = h2fs16(
505			    blocks_lastcg - cgoverhead(cylno));
506		else
507			gd[cylno].ext2bgd_nbfree = h2fs16(
508			    sblock.e2fs.e2fs_bpg - cgoverhead(cylno));
509		fbcount += fs2h16(gd[cylno].ext2bgd_nbfree);
510		if (cylno == 0) {
511			/* take reserved inodes off nifree */
512			gd[cylno].ext2bgd_nifree = h2fs16(
513			    sblock.e2fs.e2fs_ipg-EXT2_RESERVED_INODES);
514		} else {
515			gd[cylno].ext2bgd_nifree =
516			    h2fs16(sblock.e2fs.e2fs_ipg);
517		}
518		ficount += fs2h16(gd[cylno].ext2bgd_nifree);
519		gd[cylno].ext2bgd_ndirs = 0;
520	}
521	sblock.e2fs.e2fs_fbcount = fbcount;
522	sblock.e2fs.e2fs_ficount = ficount;
523
524	/*
525	 * Dump out summary information about file system.
526	 */
527	if (verbosity > 0) {
528		printf("%s: %u.%1uMB (%" PRId64 " sectors) "
529		    "block size %u, fragment size %u\n",
530		    fsys,
531		    (uint)(((uint64_t)bcount * bsize) / (1024 * 1024)),
532		    (uint)((uint64_t)bcount * bsize -
533		    rounddown((uint64_t)bcount * bsize, 1024 * 1024))
534		    / 1024 / 100,
535		    fssize, bsize, fsize);
536		printf("\tusing %u block groups of %u.0MB, %u blks, "
537		    "%u inodes.\n",
538		    ncg, bsize * sblock.e2fs.e2fs_bpg / (1024 * 1024),
539		    sblock.e2fs.e2fs_bpg, sblock.e2fs.e2fs_ipg);
540	}
541
542	/*
543	 * allocate space for superblock and group descriptors
544	 */
545	iobufsize = (NBLOCK_SUPERBLOCK + sblock.e2fs_ngdb) * sblock.e2fs_bsize;
546	iobuf = mmap(0, iobufsize, PROT_READ|PROT_WRITE,
547	    MAP_ANON|MAP_PRIVATE, -1, 0);
548	if (iobuf == NULL)
549		errx(EXIT_FAILURE, "Cannot allocate I/O buffer");
550	memset(iobuf, 0, iobufsize);
551
552	/*
553	 * We now start writing to the filesystem
554	 */
555
556	if (!Nflag) {
557		static const uint pbsize[] = { 1024, 2048, 4096, 0 };
558		uint pblock;
559		/*
560		 * Validate the given file system size.
561		 * Verify that its last block can actually be accessed.
562		 * Convert to file system fragment sized units.
563		 */
564		if (fssize <= 0)
565			errx(EXIT_FAILURE, "Preposterous size %" PRId64,
566			    fssize);
567		wtfs(fssize - 1, sectorsize, iobuf);
568
569		/*
570		 * Ensure there is nothing that looks like a filesystem
571		 * superblock anywhere other than where ours will be.
572		 *
573		 * Ext2fs superblock is always placed at the same SBOFF,
574		 * so we just zap possible first backups.
575		 */
576		for (i = 0; pbsize[i] != 0; i++) {
577 			pblock = (pbsize[i] > BBSIZE) ? 0 : 1;	/* 1st dblk */
578			pblock += pbsize[i] * NBBY;		/* next bg */
579			/* zap first backup */
580			zap_old_sblock(pblock * pbsize[i]);
581		}
582		/*
583		 * Also zap possbile FFS magic leftover to prevent
584		 * kernel vfs_mountroot() and bootloadres from mis-recognizing
585		 * this file system as FFS.
586		 */
587		zap_old_sblock(8192);	/* SBLOCK_UFS1 */
588		zap_old_sblock(65536);	/* SBLOCK_UFS2 */
589	}
590
591	if (verbosity >= 3)
592		printf("super-block backups (for fsck_ext2fs -b #) at:\n");
593	/* If we are printing more than one line of numbers, line up columns */
594	fld_width = verbosity < 4 ? 1 : snprintf(NULL, 0, "%" PRIu64,
595	    (uint64_t)cgbase(&sblock, ncg - 1));
596	/* Get terminal width */
597	if (ioctl(fileno(stdout), TIOCGWINSZ, &winsize) == 0 &&
598	    winsize.ws_col != 0)
599		max_cols = winsize.ws_col;
600	else
601		max_cols = 80;
602	if (Nflag && verbosity == 3)
603		/* Leave space to add " ..." after one row of numbers */
604		max_cols -= 4;
605#define BASE 0x10000	/* For some fixed-point maths */
606	col = 0;
607	delta = verbosity > 2 ? 0 : max_cols * BASE / ncg;
608	for (cylno = 0; cylno < ncg; cylno++) {
609		fflush(stdout);
610		initcg(cylno);
611		if (verbosity < 2)
612			continue;
613		/* the first one is a master, not backup */
614		if (cylno == 0)
615			continue;
616		/* skip if this cylinder doesn't have a backup */
617		if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
618		    (sblock.e2fs.e2fs_features_rocompat &
619		     EXT2F_ROCOMPAT_SPARSESUPER) != 0 &&
620		    cg_has_sb(cylno) == 0)
621			continue;
622
623		if (delta > 0) {
624			if (Nflag)
625				/* No point doing dots for -N */
626				break;
627			/* Print dots scaled to end near RH margin */
628			for (col += delta; col > BASE; col -= BASE)
629				printf(".");
630			continue;
631		}
632		/* Print superblock numbers */
633		len = printf("%s%*" PRIu64 ",", (col ? " " : ""), fld_width,
634		    (uint64_t)cgbase(&sblock, cylno));
635		col += len;
636		if (col + len < max_cols)
637			/* Next number fits */
638			continue;
639		/* Next number won't fit, need a newline */
640		if (verbosity <= 3) {
641			/* Print dots for subsequent cylinder groups */
642			delta = sblock.e2fs_ncg - cylno - 1;
643			if (delta != 0) {
644				if (Nflag) {
645					printf(" ...");
646					break;
647				}
648				delta = max_cols * BASE / delta;
649			}
650		}
651		col = 0;
652		printf("\n");
653	}
654#undef BASE
655	if (col > 0)
656		printf("\n");
657	if (Nflag)
658		return;
659
660	/*
661	 * Now construct the initial file system,
662	 */
663	if (fsinit(&tv) == 0)
664		errx(EXIT_FAILURE, "Error making filesystem");
665	/*
666	 * Write out the superblock and group descriptors
667	 */
668	sblock.e2fs.e2fs_block_group_nr = 0;
669	sboff = 0;
670	if (cgbase(&sblock, 0) == 0) {
671		/*
672		 * If the first block contains the boot block sectors,
673		 * (i.e. in case of sblock.e2fs.e2fs_bsize > BBSIZE)
674		 * we have to preserve data in it.
675		 */
676		sboff = SBOFF;
677	}
678	e2fs_sbsave(&sblock.e2fs, (struct ext2fs *)(iobuf + sboff));
679	e2fs_cgsave(gd, (struct ext2_gd *)(iobuf + sblock.e2fs_bsize),
680	   sizeof(struct ext2_gd) * sblock.e2fs_ncg);
681	wtfs(EXT2_FSBTODB(&sblock, cgbase(&sblock, 0)) + sboff / sectorsize,
682	    iobufsize - sboff, iobuf + sboff);
683
684	munmap(iobuf, iobufsize);
685}
686
687/*
688 * Initialize a cylinder (block) group.
689 */
690void
691initcg(uint cylno)
692{
693	uint nblcg, i, j, sboff;
694	struct ext2fs_dinode *dp;
695
696	/*
697	 * Make a copy of the superblock and group descriptors.
698	 */
699	if (sblock.e2fs.e2fs_rev == E2FS_REV0 ||
700	    (sblock.e2fs.e2fs_features_rocompat &
701	     EXT2F_ROCOMPAT_SPARSESUPER) == 0 ||
702	    cg_has_sb(cylno)) {
703		sblock.e2fs.e2fs_block_group_nr = cylno;
704		sboff = 0;
705		if (cgbase(&sblock, cylno) == 0) {
706			/* preserve data in bootblock in cg0 */
707			sboff = SBOFF;
708		}
709		e2fs_sbsave(&sblock.e2fs, (struct ext2fs *)(iobuf + sboff));
710		e2fs_cgsave(gd, (struct ext2_gd *)(iobuf +
711		    sblock.e2fs_bsize * NBLOCK_SUPERBLOCK),
712		    sizeof(struct ext2_gd) * sblock.e2fs_ncg);
713		/* write superblock and group descriptor backups */
714		wtfs(EXT2_FSBTODB(&sblock, cgbase(&sblock, cylno)) +
715		    sboff / sectorsize, iobufsize - sboff, iobuf + sboff);
716	}
717
718	/*
719	 * Initialize block bitmap.
720	 */
721	memset(buf, 0, sblock.e2fs_bsize);
722	if (cylno == (sblock.e2fs_ncg - 1)) {
723		/* The last group could have less blocks than e2fs_bpg. */
724		nblcg = sblock.e2fs.e2fs_bcount -
725		    cgbase(&sblock, sblock.e2fs_ncg - 1);
726		for (i = nblcg; i < roundup(nblcg, NBBY); i++)
727			setbit(buf, i);
728		memset(&buf[i / NBBY], ~0U, sblock.e2fs.e2fs_bpg - i);
729	}
730	/* set overhead (superblock, group descriptor etc.) blocks used */
731	for (i = 0; i < cgoverhead(cylno) / NBBY; i++)
732		buf[i] = ~0;
733	i = i * NBBY;
734	for (; i < cgoverhead(cylno); i++)
735		setbit(buf, i);
736	wtfs(EXT2_FSBTODB(&sblock, fs2h32(gd[cylno].ext2bgd_b_bitmap)),
737	    sblock.e2fs_bsize, buf);
738
739	/*
740	 * Initialize inode bitmap.
741	 *
742	 *  Assume e2fs_ipg is a multiple of NBBY since
743	 *  it's a multiple of e2fs_ipb (as we did above).
744	 *  Note even (possibly smaller) the last group has the same e2fs_ipg.
745	 */
746	i = sblock.e2fs.e2fs_ipg / NBBY;
747	memset(buf, 0, i);
748	memset(buf + i, ~0U, sblock.e2fs_bsize - i);
749	if (cylno == 0) {
750		/* mark reserved inodes */
751		for (i = 1; i < EXT2_FIRSTINO; i++)
752			setbit(buf, EXT2_INO_INDEX(i));
753	}
754	wtfs(EXT2_FSBTODB(&sblock, fs2h32(gd[cylno].ext2bgd_i_bitmap)),
755	    sblock.e2fs_bsize, buf);
756
757	/*
758	 * Initialize inode tables.
759	 *
760	 *  Just initialize generation numbers for NFS security.
761	 *  XXX: sys/ufs/ext2fs/ext2fs_alloc.c:ext2fs_valloc() seems
762	 *       to override these generated numbers.
763	 */
764	memset(buf, 0, sblock.e2fs_bsize);
765	for (i = 0; i < sblock.e2fs_itpg; i++) {
766		for (j = 0; j < sblock.e2fs_ipb; j++) {
767			dp = (struct ext2fs_dinode *)(buf + inodesize * j);
768			/* h2fs32() just for consistency */
769			dp->e2di_gen = h2fs32(arc4random());
770		}
771		wtfs(EXT2_FSBTODB(&sblock, fs2h32(gd[cylno].ext2bgd_i_tables) + i),
772		    sblock.e2fs_bsize, buf);
773	}
774}
775
776/*
777 * Zap possible lingering old superblock data
778 */
779static void
780zap_old_sblock(int sblkoff)
781{
782	static int cg0_data;
783	uint32_t oldfs[SBSIZE / sizeof(uint32_t)];
784	static const struct fsm {
785		uint32_t offset;
786		uint32_t magic;
787		uint32_t mask;
788	} fs_magics[] = {
789		{offsetof(struct ext2fs, e2fs_magic) / 4, E2FS_MAGIC, 0xffff},
790		{offsetof(struct ext2fs, e2fs_magic) / 4,
791		    E2FS_MAGIC << 16, 0xffff0000},
792		{14, 0xef530000, 0xffff0000},	/* EXT2FS (big) */
793		{0x55c / 4, 0x00011954, ~0U},	/* FS_UFS1_MAGIC */
794		{0x55c / 4, 0x19540119, ~0U},	/* FS_UFS2_MAGIC */
795		{0, 0x70162, ~0U},		/* LFS_MAGIC */
796		{.offset = ~0U},
797	};
798	const struct fsm *fsm;
799
800	if (Nflag)
801		return;
802
803	/* don't override data before superblock */
804	if (sblkoff < SBOFF)
805		return;
806
807	if (cg0_data == 0) {
808		cg0_data =
809		    ((daddr_t)sblock.e2fs.e2fs_first_dblock + cgoverhead(0)) *
810		    sblock.e2fs_bsize;
811	}
812
813	/* Ignore anything that is beyond our filesystem */
814	if (sblkoff / sectorsize >= fssize)
815		return;
816	/* Zero anything inside our filesystem... */
817	if (sblkoff >= sblock.e2fs.e2fs_first_dblock * bsize) {
818		/* ...unless we will write that area anyway */
819		if (sblkoff >= cg0_data)
820			/* assume iobuf is zero'ed here */
821			wtfs(sblkoff / sectorsize,
822			    roundup(SBSIZE, sectorsize), iobuf);
823		return;
824	}
825
826	/*
827	 * The sector might contain boot code, so we must validate it
828	 *
829	 * XXX: ext2fs won't preserve data after SBOFF,
830	 *      but first_dblock could have a different value.
831	 */
832	rdfs(sblkoff / sectorsize, sizeof(oldfs), &oldfs);
833	for (fsm = fs_magics;; fsm++) {
834		uint32_t v;
835		if (fsm->mask == 0)
836			return;
837		v = oldfs[fsm->offset];
838		if ((v & fsm->mask) == fsm->magic ||
839		    (bswap32(v) & fsm->mask) == fsm->magic)
840			break;
841	}
842
843	/* Just zap the magic number */
844	oldfs[fsm->offset] = 0;
845	wtfs(sblkoff / sectorsize, sizeof(oldfs), &oldfs);
846}
847
848/*
849 * uint cgoverhead(uint c)
850 *
851 * 	Return a number of reserved blocks on the specified group.
852 * 	XXX: should be shared with src/sbin/fsck_ext2fs/setup.c
853 */
854uint
855cgoverhead(uint c)
856{
857	uint overh;
858
859	overh = NBLOCK_BLOCK_BITMAP + NBLOCK_INODE_BITMAP + sblock.e2fs_itpg;
860
861	if (sblock.e2fs.e2fs_rev == E2FS_REV0 ||
862	    (sblock.e2fs.e2fs_features_rocompat &
863	     EXT2F_ROCOMPAT_SPARSESUPER) == 0 ||
864	    cg_has_sb(c) != 0) {
865		overh += NBLOCK_SUPERBLOCK + sblock.e2fs_ngdb;
866
867		if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
868		    (sblock.e2fs.e2fs_features_compat &
869		     EXT2F_COMPAT_RESIZE) != 0)
870			overh += sblock.e2fs.e2fs_reserved_ngdb;
871	}
872
873	return overh;
874}
875
876/*
877 * Initialize the file system
878 */
879
880#define LOSTDIR		/* e2fsck complains if there is no lost+found */
881
882#define	PREDEFDIR	2
883
884#ifdef LOSTDIR
885#define	PREDEFROOTDIR	(PREDEFDIR + 1)
886#else
887#define	PREDEFROOTDIR	PREDEFDIR
888#endif
889
890struct ext2fs_direct root_dir[] = {
891	{ EXT2_ROOTINO, 0, 1, 0, "." },
892	{ EXT2_ROOTINO, 0, 2, 0, ".." },
893#ifdef LOSTDIR
894	{ EXT2_LOSTFOUNDINO, 0, 10, 0, "lost+found" },
895#endif
896};
897
898#ifdef LOSTDIR
899struct ext2fs_direct lost_found_dir[] = {
900	{ EXT2_LOSTFOUNDINO, 0, 1, 0, "." },
901	{ EXT2_ROOTINO, 0, 2, 0, ".." },
902};
903struct ext2fs_direct pad_dir = { 0, sizeof(struct ext2fs_direct), 0, 0, "" };
904#endif
905
906int
907fsinit(const struct timeval *tv)
908{
909	struct ext2fs_dinode node;
910#ifdef LOSTDIR
911	uint i, nblks_lostfound, blk;
912#endif
913
914	/*
915	 * Initialize the inode for the resizefs feature
916	 */
917	if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
918	    (sblock.e2fs.e2fs_features_compat & EXT2F_COMPAT_RESIZE) != 0)
919		init_resizeino(tv);
920
921	/*
922	 * Initialize the node
923	 */
924
925#ifdef LOSTDIR
926	/*
927	 * Create the lost+found directory
928	 */
929	if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
930	    sblock.e2fs.e2fs_features_incompat & EXT2F_INCOMPAT_FTYPE) {
931		lost_found_dir[0].e2d_type = EXT2_FT_DIR;
932		lost_found_dir[1].e2d_type = EXT2_FT_DIR;
933	}
934	(void)makedir(lost_found_dir, __arraycount(lost_found_dir));
935
936	/* prepare a bit large directory for preserved files */
937	nblks_lostfound = EXT2_LOSTFOUNDSIZE / sblock.e2fs_bsize;
938	/* ...but only with direct blocks */
939	if (nblks_lostfound > EXT2FS_NDADDR)
940		nblks_lostfound = EXT2FS_NDADDR;
941
942	memset(&node, 0, sizeof(node));
943	node.e2di_mode = EXT2_IFDIR | EXT2_LOSTFOUNDUMASK;
944	node.e2di_uid = geteuid();
945	node.e2di_size = sblock.e2fs_bsize * nblks_lostfound;
946	node.e2di_atime = tv->tv_sec;
947	node.e2di_ctime = tv->tv_sec;
948	node.e2di_mtime = tv->tv_sec;
949	node.e2di_gid = getegid();
950	node.e2di_nlink = PREDEFDIR;
951	/* e2di_nblock is a number of disk blocks, not ext2fs blocks */
952	node.e2di_nblock = EXT2_FSBTODB(&sblock, nblks_lostfound);
953	node.e2di_blocks[0] = alloc(sblock.e2fs_bsize, node.e2di_mode);
954	if (node.e2di_blocks[0] == 0) {
955		printf("%s: can't allocate block for lost+found\n", __func__);
956		return 0;
957	}
958	for (i = 1; i < nblks_lostfound; i++) {
959		blk = alloc(sblock.e2fs_bsize, 0);
960		if (blk == 0) {
961			printf("%s: can't allocate blocks for lost+found\n",
962			    __func__);
963			return 0;
964		}
965		node.e2di_blocks[i] = blk;
966	}
967	wtfs(EXT2_FSBTODB(&sblock, node.e2di_blocks[0]),
968	    sblock.e2fs_bsize, buf);
969	pad_dir.e2d_reclen = sblock.e2fs_bsize;
970	for (i = 1; i < nblks_lostfound; i++) {
971		memset(buf, 0, sblock.e2fs_bsize);
972		copy_dir(&pad_dir, (struct ext2fs_direct *)buf);
973		wtfs(EXT2_FSBTODB(&sblock, node.e2di_blocks[i]),
974		    sblock.e2fs_bsize, buf);
975	}
976	iput(&node, EXT2_LOSTFOUNDINO);
977#endif
978	/*
979	 * create the root directory
980	 */
981	memset(&node, 0, sizeof(node));
982	if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
983	    sblock.e2fs.e2fs_features_incompat & EXT2F_INCOMPAT_FTYPE) {
984		root_dir[0].e2d_type = EXT2_FT_DIR;
985		root_dir[1].e2d_type = EXT2_FT_DIR;
986#ifdef LOSTDIR
987		root_dir[2].e2d_type = EXT2_FT_DIR;
988#endif
989	}
990	node.e2di_mode = EXT2_IFDIR | EXT2_UMASK;
991	node.e2di_uid = geteuid();
992	node.e2di_size = makedir(root_dir, __arraycount(root_dir));
993	node.e2di_atime = tv->tv_sec;
994	node.e2di_ctime = tv->tv_sec;
995	node.e2di_mtime = tv->tv_sec;
996	node.e2di_gid = getegid();
997	node.e2di_nlink = PREDEFROOTDIR;
998	/* e2di_nblock is a number of disk block, not ext2fs block */
999	node.e2di_nblock = EXT2_FSBTODB(&sblock, 1);
1000	node.e2di_blocks[0] = alloc(node.e2di_size, node.e2di_mode);
1001	if (node.e2di_blocks[0] == 0) {
1002		printf("%s: can't allocate block for root dir\n", __func__);
1003		return 0;
1004	}
1005	wtfs(EXT2_FSBTODB(&sblock, node.e2di_blocks[0]),
1006	    sblock.e2fs_bsize, buf);
1007	iput(&node, EXT2_ROOTINO);
1008	return 1;
1009}
1010
1011/*
1012 * Construct a set of directory entries in "buf".
1013 * return size of directory.
1014 */
1015int
1016makedir(struct ext2fs_direct *protodir, int entries)
1017{
1018	uint8_t *cp;
1019	uint i, spcleft;
1020	uint dirblksiz;
1021
1022	dirblksiz = sblock.e2fs_bsize;
1023	memset(buf, 0, dirblksiz);
1024	spcleft = dirblksiz;
1025	for (cp = buf, i = 0; i < entries - 1; i++) {
1026		protodir[i].e2d_reclen = EXT2FS_DIRSIZ(protodir[i].e2d_namlen);
1027		copy_dir(&protodir[i], (struct ext2fs_direct *)cp);
1028		cp += protodir[i].e2d_reclen;
1029		spcleft -= protodir[i].e2d_reclen;
1030	}
1031	protodir[i].e2d_reclen = spcleft;
1032	copy_dir(&protodir[i], (struct ext2fs_direct *)cp);
1033	return dirblksiz;
1034}
1035
1036/*
1037 * Copy a direntry to a buffer, in fs byte order
1038 */
1039static void
1040copy_dir(struct ext2fs_direct *dir, struct ext2fs_direct *dbuf)
1041{
1042
1043	memcpy(dbuf, dir, EXT2FS_DIRSIZ(dir->e2d_namlen));
1044	dbuf->e2d_ino = h2fs32(dir->e2d_ino);
1045	dbuf->e2d_reclen = h2fs16(dir->e2d_reclen);
1046}
1047
1048/*
1049 * void init_resizeino(const struct timeval *tv);
1050 *
1051 *	Initialize the EXT2_RESEIZE_INO inode to preserve
1052 *	reserved group descriptor blocks for future growth of this ext2fs.
1053 */
1054void
1055init_resizeino(const struct timeval *tv)
1056{
1057	struct ext2fs_dinode node;
1058	uint64_t isize;
1059	uint32_t *dindir_block, *reserved_gdb;
1060	uint nblock, i, cylno, n;
1061
1062	memset(&node, 0, sizeof(node));
1063
1064	/*
1065	 * Note this function only prepares required structures for
1066	 * future resize. It's a quite different work to implement
1067	 * a utility like resize_ext2fs(8) which handles actual
1068	 * resize ops even on offline.
1069	 *
1070	 * Anyway, I'm not sure if there is any documentation about
1071	 * this resize ext2fs feature and related data structures,
1072	 * and I've written this function based on things what I see
1073	 * on some existing implementation and real file system data
1074	 * created by existing tools. To be honest, they are not
1075	 * so easy to read, so I will try to implement it here without
1076	 * any dumb optimization for people who would eventually
1077	 * work on "yet another wheel" like resize_ext2fs(8).
1078	 */
1079
1080	/*
1081	 * I'm not sure what type is appropriate for this inode.
1082	 * The release notes of e2fsprogs says they changed e2fsck to allow
1083	 * IFREG for RESIZEINO since a certain resize tool used it. Hmm.
1084	 */
1085	node.e2di_mode = EXT2_IFREG | EXT2_RESIZEINOUMASK;
1086	node.e2di_uid = geteuid();
1087	node.e2di_atime = tv->tv_sec;
1088	node.e2di_ctime = tv->tv_sec;
1089	node.e2di_mtime = tv->tv_sec;
1090	node.e2di_gid = getegid();
1091	node.e2di_nlink = 1;
1092
1093	/*
1094	 * To preserve the reserved group descriptor blocks,
1095	 * EXT2_RESIZEINO uses only double indirect reference
1096	 * blocks in its inode entries.
1097	 *
1098	 * All entries for direct, single indirect and triple
1099	 * indirect references are left zero'ed. Maybe it's safe
1100	 * because no write operation will happen with this inode.
1101	 *
1102	 * We have to allocate a block for the first level double
1103	 * indirect reference block. Indexes of inode entries in
1104	 * this first level dindirect block are corresponding to
1105	 * indexes of group descriptors including both used (e2fs_ngdb)
1106	 * and reserved (e2fs_reserved_ngdb) group descriptor blocks.
1107	 *
1108	 * Inode entries of indexes for used (e2fs_ngdb) descriptors are
1109	 * left zero'ed. Entries for reserved (e2fs_reserved_ngdb) ones
1110	 * have block numbers of actual reserved group descriptors
1111	 * allocated at block group zero. This means e2fs_reserved_ngdb
1112	 * blocks are reserved as the second level dindirect reference
1113	 * blocks, and they actually contain block numbers of indirect
1114	 * references. It may be safe since they don't have to keep any
1115	 * data yet.
1116	 *
1117	 * Each these second dindirect blocks (i.e. reserved group
1118	 * descriptor blocks in the first block group) should have
1119	 * block numbers of its backups in all other block groups.
1120	 * I.e. reserved_ngdb[0] block in block group 0 contains block
1121	 * numbers of resreved_ngdb[0] from group 1 through (e2fs_ncg - 1).
1122	 * The number of backups can be determined by the
1123	 * EXT2_ROCOMPAT_SPARSESUPER feature and cg_has_sb() macro
1124	 * as done in the above initcg() function.
1125	 */
1126
1127	/* set e2di_size which occupies whole blocks through DINDIR blocks */
1128	isize = (uint64_t)sblock.e2fs_bsize * EXT2FS_NDADDR +
1129	    (uint64_t)sblock.e2fs_bsize * EXT2_NINDIR(&sblock) +
1130	    (uint64_t)sblock.e2fs_bsize * EXT2_NINDIR(&sblock) *
1131	    EXT2_NINDIR(&sblock);
1132	if (isize > UINT32_MAX &&
1133	    (sblock.e2fs.e2fs_features_rocompat &
1134	     EXT2F_ROCOMPAT_LARGEFILE) == 0) {
1135		/* XXX should enable it here and update all backups? */
1136		errx(EXIT_FAILURE, "%s: large_file rocompat feature is "
1137		    "required to enable resize feature for this filesystem",
1138		    __func__);
1139	}
1140	/* upper 32bit is stored into e2di_size_high on REV1 feature */
1141	node.e2di_size 	    = isize & UINT32_MAX;
1142	node.e2di_size_high = isize >> 32;
1143
1144#define SINGLE	0	/* index of single indirect block */
1145#define DOUBLE	1	/* index of double indirect block */
1146#define TRIPLE	2	/* index of triple indirect block */
1147
1148	/* zero out entries for direct references */
1149	for (i = 0; i < EXT2FS_NDADDR; i++)
1150		node.e2di_blocks[i] = 0;
1151	/* also zero out entries for single and triple indirect references */
1152	node.e2di_blocks[EXT2FS_NDADDR + SINGLE] = 0;
1153	node.e2di_blocks[EXT2FS_NDADDR + TRIPLE] = 0;
1154
1155	/* allocate a block for the first level double indirect reference */
1156	node.e2di_blocks[EXT2FS_NDADDR + DOUBLE] =
1157	    alloc(sblock.e2fs_bsize, node.e2di_mode);
1158	if (node.e2di_blocks[EXT2FS_NDADDR + DOUBLE] == 0)
1159		errx(EXIT_FAILURE, "%s: Can't allocate a dindirect block",
1160		    __func__);
1161
1162	/* account this first block */
1163	nblock = EXT2_FSBTODB(&sblock, 1);
1164
1165	/* allocate buffer to set data in the dindirect block */
1166	dindir_block = malloc(sblock.e2fs_bsize);
1167	if (dindir_block == NULL)
1168		errx(EXIT_FAILURE,
1169		    "%s: Can't allocate buffer for a dindirect block",
1170		    __func__);
1171
1172	/* allocate buffer to set data in the group descriptor blocks */
1173	reserved_gdb = malloc(sblock.e2fs_bsize);
1174	if (reserved_gdb == NULL)
1175		errx(EXIT_FAILURE,
1176		    "%s: Can't allocate buffer for group descriptor blocks",
1177		    __func__);
1178
1179	/*
1180	 * Setup block entries in the first level dindirect blocks
1181	 */
1182	for (i = 0; i < sblock.e2fs_ngdb; i++) {
1183		/* no need to handle used group descriptor blocks */
1184		dindir_block[i] = 0;
1185	}
1186	for (; i < sblock.e2fs_ngdb + sblock.e2fs.e2fs_reserved_ngdb; i++) {
1187		/*
1188		 * point reserved group descriptor block in the first
1189		 * (i.e. master) block group
1190		 *
1191		 * XXX: e2fsprogs seem to use "(i % EXT2_NINDIR(&sblock))" here
1192		 *      to store maximum EXT2_NINDIR(&sblock) reserved gdbs.
1193		 *      I'm not sure what will be done on future filesystem
1194		 *      shrink in that case on their way.
1195		 */
1196		if (i >= EXT2_NINDIR(&sblock))
1197			errx(EXIT_FAILURE, "%s: too many reserved "
1198			    "group descriptors (%u) for resize inode",
1199			    __func__, sblock.e2fs.e2fs_reserved_ngdb);
1200		dindir_block[i] =
1201		    h2fs32(cgbase(&sblock, 0) + NBLOCK_SUPERBLOCK + i);
1202
1203		/*
1204		 * Setup block entries in the second dindirect blocks
1205		 * (which are primary reserved group descriptor blocks)
1206		 * to point their backups.
1207		 */
1208		for (n = 0, cylno = 1; cylno < sblock.e2fs_ncg; cylno++) {
1209			/* skip block groups without backup */
1210			if ((sblock.e2fs.e2fs_features_rocompat &
1211			     EXT2F_ROCOMPAT_SPARSESUPER) != 0 &&
1212			    cg_has_sb(cylno) == 0)
1213				continue;
1214
1215			if (n >= EXT2_NINDIR(&sblock))
1216				errx(EXIT_FAILURE, "%s: too many block groups "
1217				    "for the resize feature", __func__);
1218			/*
1219			 * These blocks are already reserved in
1220			 * initcg() so no need to use alloc() here.
1221			 */
1222			reserved_gdb[n++] = h2fs32(cgbase(&sblock, cylno) +
1223			    NBLOCK_SUPERBLOCK + i);
1224			nblock += EXT2_FSBTODB(&sblock, 1);
1225		}
1226		for (; n < EXT2_NINDIR(&sblock); n++)
1227			reserved_gdb[n] = 0;
1228
1229		/* write group descriptor block as the second dindirect refs */
1230		wtfs(EXT2_FSBTODB(&sblock, fs2h32(dindir_block[i])),
1231		    sblock.e2fs_bsize, reserved_gdb);
1232		nblock += EXT2_FSBTODB(&sblock, 1);
1233	}
1234	for (; i < EXT2_NINDIR(&sblock); i++) {
1235		/* leave trailing entries unallocated */
1236		dindir_block[i] = 0;
1237	}
1238	free(reserved_gdb);
1239
1240	/* finally write the first level dindirect block */
1241	wtfs(EXT2_FSBTODB(&sblock, node.e2di_blocks[EXT2FS_NDADDR + DOUBLE]),
1242	    sblock.e2fs_bsize, dindir_block);
1243	free(dindir_block);
1244
1245	node.e2di_nblock = nblock;
1246	iput(&node, EXT2_RESIZEINO);
1247}
1248
1249/*
1250 * uint32_t alloc(uint32_t size, uint16_t mode)
1251 *
1252 *	Allocate a block (from cylinder group 0)
1253 *	Reference: src/sys/ufs/ext2fs/ext2fs_alloc.c:ext2fs_alloccg()
1254 */
1255uint32_t
1256alloc(uint32_t size, uint16_t mode)
1257{
1258	uint32_t loc, bno;
1259	uint8_t *bbp;
1260	uint len, map, i;
1261
1262	if (gd[0].ext2bgd_nbfree == 0)
1263		return 0;
1264
1265	if (size > sblock.e2fs_bsize)
1266		return 0;
1267
1268	bbp = malloc(sblock.e2fs_bsize);
1269	if (bbp == NULL)
1270		return 0;
1271	rdfs(EXT2_FSBTODB(&sblock, fs2h32(gd[0].ext2bgd_b_bitmap)),
1272	    sblock.e2fs_bsize, bbp);
1273
1274	/* XXX: kernel uses e2fs_fpg here */
1275	len = sblock.e2fs.e2fs_bpg / NBBY;
1276
1277#if 0	/* no need block allocation for root or lost+found dir */
1278	for (loc = 0; loc < len; loc++) {
1279		if (bbp[loc] == 0) {
1280			bno = loc * NBBY;
1281			goto gotit;
1282		}
1283	}
1284#endif
1285
1286	loc = skpc(~0U, len, bbp);
1287	if (loc == 0) {
1288		free(bbp);
1289		return 0;
1290	}
1291	loc = len - loc;
1292	map = bbp[loc];
1293	bno = loc * NBBY;
1294	for (i = 0; i < NBBY; i++, bno++) {
1295		if ((map & (1 << i)) == 0)
1296			goto gotit;
1297	}
1298	free(bbp);
1299	return 0;
1300
1301 gotit:
1302	if (isset(bbp, bno))
1303		errx(EXIT_FAILURE, "%s: inconsistent bitmap", __func__);
1304
1305	setbit(bbp, bno);
1306	wtfs(EXT2_FSBTODB(&sblock, fs2h32(gd[0].ext2bgd_b_bitmap)),
1307	    sblock.e2fs_bsize, bbp);
1308	free(bbp);
1309	/* XXX: modified group descriptors won't be written into backups */
1310	gd[0].ext2bgd_nbfree = h2fs16(fs2h16(gd[0].ext2bgd_nbfree)-1);
1311	if ((mode & EXT2_IFDIR) != 0)
1312		gd[0].ext2bgd_ndirs = h2fs16(fs2h16(gd[0].ext2bgd_ndirs)+1);
1313	sblock.e2fs.e2fs_fbcount--;
1314
1315	return sblock.e2fs.e2fs_first_dblock + bno;
1316}
1317
1318/*
1319 * void iput(struct ext2fs_dinode *ip, ino_t ino)
1320 *
1321 *	Put an inode entry into the corresponding table.
1322 */
1323static void
1324iput(struct ext2fs_dinode *ip, ino_t ino)
1325{
1326	daddr_t d;
1327	uint c, i;
1328	struct ext2fs_dinode *dp;
1329	uint8_t *bp;
1330
1331	bp = malloc(sblock.e2fs_bsize);
1332	if (bp == NULL)
1333		errx(EXIT_FAILURE, "%s: can't allocate buffer for inode",
1334		    __func__);
1335
1336	/*
1337	 * Reserved inodes are allocated and accounted in initcg()
1338	 * so skip checks of the bitmap and allocation for them.
1339	 */
1340	if (ino >= EXT2_FIRSTINO) {
1341		c = ino_to_cg(&sblock, ino);
1342
1343		/* sanity check */
1344		if (gd[c].ext2bgd_nifree == 0)
1345			errx(EXIT_FAILURE,
1346			    "%s: no free inode %" PRIu64 " in block group %u",
1347			    __func__, (uint64_t)ino, c);
1348
1349		/* update inode bitmap */
1350		rdfs(EXT2_FSBTODB(&sblock, fs2h32(gd[0].ext2bgd_i_bitmap)),
1351		    sblock.e2fs_bsize, bp);
1352
1353		/* more sanity */
1354		if (isset(bp, EXT2_INO_INDEX(ino)))
1355			errx(EXIT_FAILURE, "%s: inode %" PRIu64
1356			    " already in use", __func__, (uint64_t)ino);
1357		setbit(bp, EXT2_INO_INDEX(ino));
1358		wtfs(EXT2_FSBTODB(&sblock, fs2h32(gd[0].ext2bgd_i_bitmap)),
1359		    sblock.e2fs_bsize, bp);
1360		gd[c].ext2bgd_nifree = h2fs16(fs2h16(gd[c].ext2bgd_nifree)-1);
1361		sblock.e2fs.e2fs_ficount--;
1362	}
1363
1364	if (ino >= sblock.e2fs.e2fs_ipg * sblock.e2fs_ncg)
1365		errx(EXIT_FAILURE, "%s: inode value out of range (%" PRIu64
1366		    ")", __func__, (uint64_t)ino);
1367
1368	/* update an inode entry in the table */
1369	d = EXT2_FSBTODB(&sblock, ino_to_fsba(&sblock, ino));
1370	rdfs(d, sblock.e2fs_bsize, bp);
1371
1372	dp = (struct ext2fs_dinode *)(bp +
1373	    inodesize * ino_to_fsbo(&sblock, ino));
1374	e2fs_isave(ip, dp, EXT2_DINODE_SIZE(&sblock));
1375	/* e2fs_i_bswap() doesn't swap e2di_blocks addrs */
1376	if ((ip->e2di_mode & EXT2_IFMT) != EXT2_IFLNK) {
1377		for (i = 0; i < EXT2FS_NDADDR + EXT2FS_NIADDR; i++)
1378			dp->e2di_blocks[i] = h2fs32(ip->e2di_blocks[i]);
1379	}
1380	/* h2fs32() just for consistency */
1381	dp->e2di_gen = h2fs32(arc4random());
1382
1383	wtfs(d, sblock.e2fs_bsize, bp);
1384	free(bp);
1385}
1386
1387/*
1388 * Read a block from the file system
1389 */
1390void
1391rdfs(daddr_t bno, int size, void *bf)
1392{
1393	int n;
1394	off_t offset;
1395
1396	offset = bno;
1397	n = pread(fsi, bf, size, offset * sectorsize);
1398	if (n != size)
1399		err(EXIT_FAILURE, "%s: read error for sector %" PRId64,
1400		    __func__, (int64_t)bno);
1401}
1402
1403/*
1404 * Write a block to the file system
1405 */
1406void
1407wtfs(daddr_t bno, int size, void *bf)
1408{
1409	int n;
1410	off_t offset;
1411
1412	if (Nflag)
1413		return;
1414	offset = bno;
1415	n = pwrite(fso, bf, size, offset * sectorsize);
1416	if (n != size)
1417		err(EXIT_FAILURE, "%s: write error for sector %" PRId64,
1418		    __func__, (int64_t)bno);
1419}
1420
1421int
1422ilog2(uint val)
1423{
1424
1425	if (val == 0 || !powerof2(val))
1426		errx(EXIT_FAILURE, "%s: %u is not a power of 2",
1427		    __func__, val);
1428
1429	return ffs(val) - 1;
1430}
1431
1432/*
1433 * int skpc(int mask, size_t size, uint8_t *cp)
1434 *
1435 *	Locate an unsigned character of value mask inside cp[].
1436 * 	(from src/sys/lib/libkern/skpc.c)
1437 */
1438int
1439skpc(int mask, size_t size, uint8_t *cp)
1440{
1441	uint8_t *end;
1442
1443	end = &cp[size];
1444	while (cp < end && *cp == (uint8_t)mask)
1445		cp++;
1446
1447	return end - cp;
1448}
1449