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1 /*
2  * set_fields.c --- set a superblock value
3  *
4  * Copyright (C) 2000, 2001, 2002, 2003, 2004 by Theodore Ts'o.
5  *
6  * %Begin-Header%
7  * This file may be redistributed under the terms of the GNU Public
8  * License.
9  * %End-Header%
10  */
11 
12 #define _XOPEN_SOURCE 600 /* for inclusion of strptime() and strtoull */
13 
14 #ifdef HAVE_STRTOULL
15 #define STRTOULL strtoull
16 #else
17 #define STRTOULL strtoul
18 #endif
19 
20 #include <stdio.h>
21 #include <unistd.h>
22 #include <stdlib.h>
23 #include <ctype.h>
24 #include <string.h>
25 #include <strings.h>
26 #include <time.h>
27 #include <sys/types.h>
28 #include <sys/stat.h>
29 #ifdef HAVE_ERRNO_H
30 #include <errno.h>
31 #endif
32 #if HAVE_STRINGS_H
33 #include <strings.h>
34 #endif
35 #include <fcntl.h>
36 #include <utime.h>
37 
38 #include "debugfs.h"
39 #include "uuid/uuid.h"
40 #include "e2p/e2p.h"
41 
42 static struct ext2_super_block set_sb;
43 static struct ext2_inode set_inode;
44 static struct ext2_group_desc set_gd;
45 static dgrp_t set_bg;
46 static ext2_ino_t set_ino;
47 static int array_idx;
48 
49 #define FLAG_ARRAY	0x0001
50 
51 struct field_set_info {
52 	const char	*name;
53 	void	*ptr;
54 	unsigned int	size;
55 	errcode_t (*func)(struct field_set_info *info, char *arg);
56 	int flags;
57 	int max_idx;
58 };
59 
60 static errcode_t parse_uint(struct field_set_info *info, char *arg);
61 static errcode_t parse_int(struct field_set_info *info, char *arg);
62 static errcode_t parse_string(struct field_set_info *info, char *arg);
63 static errcode_t parse_uuid(struct field_set_info *info, char *arg);
64 static errcode_t parse_hashalg(struct field_set_info *info, char *arg);
65 static errcode_t parse_time(struct field_set_info *info, char *arg);
66 static errcode_t parse_bmap(struct field_set_info *info, char *arg);
67 static errcode_t parse_gd_csum(struct field_set_info *info, char *arg);
68 
69 static struct field_set_info super_fields[] = {
70 	{ "inodes_count", &set_sb.s_inodes_count, 4, parse_uint },
71 	{ "blocks_count", &set_sb.s_blocks_count, 4, parse_uint },
72 	{ "r_blocks_count", &set_sb.s_r_blocks_count, 4, parse_uint },
73 	{ "free_blocks_count", &set_sb.s_free_blocks_count, 4, parse_uint },
74 	{ "free_inodes_count", &set_sb.s_free_inodes_count, 4, parse_uint },
75 	{ "first_data_block", &set_sb.s_first_data_block, 4, parse_uint },
76 	{ "log_block_size", &set_sb.s_log_block_size, 4, parse_uint },
77 	{ "log_frag_size", &set_sb.s_log_frag_size, 4, parse_int },
78 	{ "blocks_per_group", &set_sb.s_blocks_per_group, 4, parse_uint },
79 	{ "frags_per_group", &set_sb.s_frags_per_group, 4, parse_uint },
80 	{ "inodes_per_group", &set_sb.s_inodes_per_group, 4, parse_uint },
81 	{ "mtime", &set_sb.s_mtime, 4, parse_time },
82 	{ "wtime", &set_sb.s_wtime, 4, parse_time },
83 	{ "mnt_count", &set_sb.s_mnt_count, 2, parse_uint },
84 	{ "max_mnt_count", &set_sb.s_max_mnt_count, 2, parse_int },
85 	/* s_magic */
86 	{ "state", &set_sb.s_state, 2, parse_uint },
87 	{ "errors", &set_sb.s_errors, 2, parse_uint },
88 	{ "minor_rev_level", &set_sb.s_minor_rev_level, 2, parse_uint },
89 	{ "lastcheck", &set_sb.s_lastcheck, 4, parse_time },
90 	{ "checkinterval", &set_sb.s_checkinterval, 4, parse_uint },
91 	{ "creator_os", &set_sb.s_creator_os, 4, parse_uint },
92 	{ "rev_level", &set_sb.s_rev_level, 4, parse_uint },
93 	{ "def_resuid", &set_sb.s_def_resuid, 2, parse_uint },
94 	{ "def_resgid", &set_sb.s_def_resgid, 2, parse_uint },
95 	{ "first_ino", &set_sb.s_first_ino, 4, parse_uint },
96 	{ "inode_size", &set_sb.s_inode_size, 2, parse_uint },
97 	{ "block_group_nr", &set_sb.s_block_group_nr, 2, parse_uint },
98 	{ "feature_compat", &set_sb.s_feature_compat, 4, parse_uint },
99 	{ "feature_incompat", &set_sb.s_feature_incompat, 4, parse_uint },
100 	{ "feature_ro_compat", &set_sb.s_feature_ro_compat, 4, parse_uint },
101 	{ "uuid", &set_sb.s_uuid, 16, parse_uuid },
102 	{ "volume_name",  &set_sb.s_volume_name, 16, parse_string },
103 	{ "last_mounted",  &set_sb.s_last_mounted, 64, parse_string },
104 	{ "lastcheck",  &set_sb.s_lastcheck, 4, parse_uint },
105 	{ "algorithm_usage_bitmap", &set_sb.s_algorithm_usage_bitmap,
106 		  4, parse_uint },
107 	{ "prealloc_blocks", &set_sb.s_prealloc_blocks, 1, parse_uint },
108 	{ "prealloc_dir_blocks", &set_sb.s_prealloc_dir_blocks, 1,
109 		  parse_uint },
110 	{ "reserved_gdt_blocks", &set_sb.s_reserved_gdt_blocks, 2,
111 		  parse_uint },
112 	{ "journal_uuid", &set_sb.s_journal_uuid, 16, parse_uuid },
113 	{ "journal_inum", &set_sb.s_journal_inum, 4, parse_uint },
114 	{ "journal_dev", &set_sb.s_journal_dev, 4, parse_uint },
115 	{ "last_orphan", &set_sb.s_last_orphan, 4, parse_uint },
116 	{ "hash_seed", &set_sb.s_hash_seed, 16, parse_uuid },
117 	{ "def_hash_version", &set_sb.s_def_hash_version, 1, parse_hashalg },
118 	{ "jnl_backup_type", &set_sb.s_jnl_backup_type, 1, parse_uint },
119 	{ "desc_size", &set_sb.s_desc_size, 2, parse_uint },
120 	{ "default_mount_opts", &set_sb.s_default_mount_opts, 4, parse_uint },
121 	{ "first_meta_bg", &set_sb.s_first_meta_bg, 4, parse_uint },
122 	{ "mkfs_time", &set_sb.s_mkfs_time, 4, parse_time },
123 	{ "jnl_blocks", &set_sb.s_jnl_blocks[0], 4, parse_uint, FLAG_ARRAY,
124 	  17 },
125 	{ "blocks_count_hi", &set_sb.s_blocks_count_hi, 4, parse_uint },
126 	{ "r_blocks_count_hi", &set_sb.s_r_blocks_count_hi, 4, parse_uint },
127 	{ "min_extra_isize", &set_sb.s_min_extra_isize, 2, parse_uint },
128 	{ "want_extra_isize", &set_sb.s_want_extra_isize, 2, parse_uint },
129 	{ "flags", &set_sb.s_flags, 4, parse_uint },
130 	{ "raid_stride", &set_sb.s_raid_stride, 2, parse_uint },
131 	{ "min_extra_isize", &set_sb.s_min_extra_isize, 4, parse_uint },
132 	{ "mmp_interval", &set_sb.s_mmp_interval, 2, parse_uint },
133 	{ "mmp_block", &set_sb.s_mmp_block, 8, parse_uint },
134 	{ "raid_stripe_width", &set_sb.s_raid_stripe_width, 4, parse_uint },
135 	{ "log_groups_per_flex", &set_sb.s_log_groups_per_flex, 1, parse_uint },
136 	{ "kbytes_written", &set_sb.s_kbytes_written, 8, parse_uint },
137 	{ 0, 0, 0, 0 }
138 };
139 
140 static struct field_set_info inode_fields[] = {
141 	{ "inodes_count", &set_sb.s_inodes_count, 4, parse_uint },
142 	{ "mode", &set_inode.i_mode, 2, parse_uint },
143 	{ "uid", &set_inode.i_uid, 2, parse_uint },
144 	{ "size", &set_inode.i_size, 4, parse_uint },
145 	{ "atime", &set_inode.i_atime, 4, parse_time },
146 	{ "ctime", &set_inode.i_ctime, 4, parse_time },
147 	{ "mtime", &set_inode.i_mtime, 4, parse_time },
148 	{ "dtime", &set_inode.i_dtime, 4, parse_time },
149 	{ "gid", &set_inode.i_gid, 2, parse_uint },
150 	{ "links_count", &set_inode.i_links_count, 2, parse_uint },
151 	{ "blocks", &set_inode.i_blocks, 4, parse_uint },
152 	{ "flags", &set_inode.i_flags, 4, parse_uint },
153 	{ "version", &set_inode.osd1.linux1.l_i_version, 4, parse_uint },
154 	{ "translator", &set_inode.osd1.hurd1.h_i_translator, 4, parse_uint },
155 	{ "block", &set_inode.i_block[0], 4, parse_uint, FLAG_ARRAY,
156 	  EXT2_NDIR_BLOCKS },
157 	{ "block[IND]", &set_inode.i_block[EXT2_IND_BLOCK], 4, parse_uint },
158 	{ "block[DIND]", &set_inode.i_block[EXT2_DIND_BLOCK], 4, parse_uint },
159 	{ "block[TIND]", &set_inode.i_block[EXT2_TIND_BLOCK], 4, parse_uint },
160 	{ "generation", &set_inode.i_generation, 4, parse_uint },
161 	{ "file_acl", &set_inode.i_file_acl, 4, parse_uint },
162 	{ "file_acl_high", &set_inode.osd2.linux2.l_i_file_acl_high, 2,
163 	  parse_uint },
164 	{ "dir_acl", &set_inode.i_dir_acl, 4, parse_uint },
165 	{ "size_high", &set_inode.i_size_high, 4, parse_uint },
166 	{ "faddr", &set_inode.i_faddr, 4, parse_uint },
167 	{ "blocks_hi", &set_inode.osd2.linux2.l_i_blocks_hi, 2, parse_uint },
168 	{ "frag", &set_inode.osd2.hurd2.h_i_frag, 1, parse_uint },
169 	{ "fsize", &set_inode.osd2.hurd2.h_i_fsize, 1, parse_uint },
170 	{ "uid_high", &set_inode.osd2.linux2.l_i_uid_high, 2, parse_uint },
171 	{ "gid_high", &set_inode.osd2.linux2.l_i_gid_high, 2, parse_uint },
172 	{ "author", &set_inode.osd2.hurd2.h_i_author, 4, parse_uint },
173 	{ "bmap", NULL, 4, parse_bmap, FLAG_ARRAY },
174 	{ 0, 0, 0, 0 }
175 };
176 
177 static struct field_set_info ext2_bg_fields[] = {
178 	{ "block_bitmap", &set_gd.bg_block_bitmap, 4, parse_uint },
179 	{ "inode_bitmap", &set_gd.bg_inode_bitmap, 4, parse_uint },
180 	{ "inode_table", &set_gd.bg_inode_table, 4, parse_uint },
181 	{ "free_blocks_count", &set_gd.bg_free_blocks_count, 2, parse_uint },
182 	{ "free_inodes_count", &set_gd.bg_free_inodes_count, 2, parse_uint },
183 	{ "used_dirs_count", &set_gd.bg_used_dirs_count, 2, parse_uint },
184 	{ "flags", &set_gd.bg_flags, 2, parse_uint },
185 	{ "reserved", &set_gd.bg_reserved, 2, parse_uint, FLAG_ARRAY, 2 },
186 	{ "itable_unused", &set_gd.bg_itable_unused, 2, parse_uint },
187 	{ "checksum", &set_gd.bg_checksum, 2, parse_gd_csum },
188 	{ 0, 0, 0, 0 }
189 };
190 
191 
find_field(struct field_set_info * fields,char * field)192 static struct field_set_info *find_field(struct field_set_info *fields,
193 					 char *field)
194 {
195 	struct field_set_info *ss;
196 	const char	*prefix;
197 	char		*arg, *delim, *idx, *tmp;
198 	int		prefix_len;
199 
200 	if (fields == super_fields)
201 		prefix = "s_";
202 	else if (fields == inode_fields)
203 		prefix = "i_";
204 	else
205 		prefix = "bg_";
206 	prefix_len = strlen(prefix);
207 	if (strncmp(field, prefix, prefix_len) == 0)
208 		field += prefix_len;
209 
210 	arg = malloc(strlen(field)+1);
211 	if (!arg)
212 		return NULL;
213 	strcpy(arg, field);
214 
215 	idx = strchr(arg, '[');
216 	if (idx) {
217 		*idx++ = 0;
218 		delim = idx + strlen(idx) - 1;
219 		if (!*idx || *delim != ']')
220 			idx = 0;
221 		else
222 			*delim = 0;
223 	}
224 	/*
225 	 * Can we parse the number?
226 	 */
227 	if (idx) {
228 		array_idx = strtol(idx, &tmp, 0);
229 		if (*tmp)
230 			idx = 0;
231 	}
232 
233 	for (ss = fields ; ss->name ; ss++) {
234 		if (ss->flags & FLAG_ARRAY) {
235 			if (!idx || (strcmp(ss->name, arg) != 0))
236 				continue;
237 			if (ss->max_idx > 0 && array_idx >= ss->max_idx)
238 				continue;
239 		} else {
240 			if (strcmp(ss->name, field) != 0)
241 				continue;
242 		}
243 		free(arg);
244 		return ss;
245 	}
246 	free(arg);
247 	return NULL;
248 }
249 
parse_uint(struct field_set_info * info,char * arg)250 static errcode_t parse_uint(struct field_set_info *info, char *arg)
251 {
252 	unsigned long long num, limit;
253 	char *tmp;
254 	union {
255 		__u64	*ptr64;
256 		__u32	*ptr32;
257 		__u16	*ptr16;
258 		__u8	*ptr8;
259 	} u;
260 
261 	u.ptr8 = (__u8 *) info->ptr;
262 	if (info->flags & FLAG_ARRAY)
263 		u.ptr8 += array_idx * info->size;
264 
265 	errno = 0;
266 	num = STRTOULL(arg, &tmp, 0);
267 	if (*tmp || errno) {
268 		fprintf(stderr, "Couldn't parse '%s' for field %s.\n",
269 			arg, info->name);
270 		return EINVAL;
271 	}
272 	limit = ~0ULL >> ((8 - info->size) * 8);
273 	if (num > limit) {
274 		fprintf(stderr, "Value '%s' exceeds field %s maximum %llu.\n",
275 			arg, info->name, limit);
276 		return EINVAL;
277 	}
278 	switch (info->size) {
279 	case 8:
280 		*u.ptr64 = num;
281 		break;
282 	case 4:
283 		*u.ptr32 = num;
284 		break;
285 	case 2:
286 		*u.ptr16 = num;
287 		break;
288 	case 1:
289 		*u.ptr8 = num;
290 		break;
291 	}
292 	return 0;
293 }
294 
parse_int(struct field_set_info * info,char * arg)295 static errcode_t parse_int(struct field_set_info *info, char *arg)
296 {
297 	long	num;
298 	char *tmp;
299 	__s32	*ptr32;
300 	__s16	*ptr16;
301 	__s8	*ptr8;
302 
303 	num = strtol(arg, &tmp, 0);
304 	if (*tmp) {
305 		fprintf(stderr, "Couldn't parse '%s' for field %s.\n",
306 			arg, info->name);
307 		return EINVAL;
308 	}
309 	switch (info->size) {
310 	case 4:
311 		ptr32 = (__s32 *) info->ptr;
312 		*ptr32 = num;
313 		break;
314 	case 2:
315 		ptr16 = (__s16 *) info->ptr;
316 		*ptr16 = num;
317 		break;
318 	case 1:
319 		ptr8 = (__s8 *) info->ptr;
320 		*ptr8 = num;
321 		break;
322 	}
323 	return 0;
324 }
325 
parse_string(struct field_set_info * info,char * arg)326 static errcode_t parse_string(struct field_set_info *info, char *arg)
327 {
328 	char	*cp = (char *) info->ptr;
329 
330 	if (strlen(arg) >= info->size) {
331 		fprintf(stderr, "Error maximum size for %s is %d.\n",
332 			info->name, info->size);
333 		return EINVAL;
334 	}
335 	strcpy(cp, arg);
336 	return 0;
337 }
338 
parse_time(struct field_set_info * info,char * arg)339 static errcode_t parse_time(struct field_set_info *info, char *arg)
340 {
341 	time_t		t;
342 	__u32		*ptr32;
343 
344 	ptr32 = (__u32 *) info->ptr;
345 
346 	t = string_to_time(arg);
347 
348 	if (t == ((time_t) -1)) {
349 		fprintf(stderr, "Couldn't parse '%s' for field %s.\n",
350 			arg, info->name);
351 		return EINVAL;
352 	}
353 	*ptr32 = t;
354 	return 0;
355 }
356 
parse_uuid(struct field_set_info * info,char * arg)357 static errcode_t parse_uuid(struct field_set_info *info, char *arg)
358 {
359 	unsigned char *	p = (unsigned char *) info->ptr;
360 
361 	if ((strcasecmp(arg, "null") == 0) ||
362 	    (strcasecmp(arg, "clear") == 0)) {
363 		uuid_clear(p);
364 	} else if (strcasecmp(arg, "time") == 0) {
365 		uuid_generate_time(p);
366 	} else if (strcasecmp(arg, "random") == 0) {
367 		uuid_generate(p);
368 	} else if (uuid_parse(arg, p)) {
369 		fprintf(stderr, "Invalid UUID format: %s\n", arg);
370 		return EINVAL;
371 	}
372 	return 0;
373 }
374 
parse_hashalg(struct field_set_info * info,char * arg)375 static errcode_t parse_hashalg(struct field_set_info *info, char *arg)
376 {
377 	int	hashv;
378 	unsigned char	*p = (unsigned char *) info->ptr;
379 
380 	hashv = e2p_string2hash(arg);
381 	if (hashv < 0) {
382 		fprintf(stderr, "Invalid hash algorithm: %s\n", arg);
383 		return EINVAL;
384 	}
385 	*p = hashv;
386 	return 0;
387 }
388 
parse_bmap(struct field_set_info * info,char * arg)389 static errcode_t parse_bmap(struct field_set_info *info, char *arg)
390 {
391 	unsigned long	num;
392 	blk_t		blk;
393 	errcode_t	retval;
394 	char		*tmp;
395 
396 	num = strtoul(arg, &tmp, 0);
397 	if (*tmp) {
398 		fprintf(stderr, "Couldn't parse '%s' for field %s.\n",
399 			arg, info->name);
400 		return EINVAL;
401 	}
402 	blk = num;
403 
404 	retval = ext2fs_bmap(current_fs, set_ino, &set_inode, 0, BMAP_SET,
405 			     array_idx, &blk);
406 	if (retval) {
407 		com_err("set_inode", retval, "while setting block map");
408 	}
409 	return retval;
410 }
411 
parse_gd_csum(struct field_set_info * info,char * arg)412 static errcode_t parse_gd_csum(struct field_set_info *info, char *arg)
413 {
414 
415 	if (strcmp(arg, "calc") == 0) {
416 		ext2fs_group_desc_csum_set(current_fs, set_bg);
417 		set_gd = current_fs->group_desc[set_bg];
418 		printf("Checksum set to 0x%04x\n",
419 		       current_fs->group_desc[set_bg].bg_checksum);
420 		return 0;
421 	}
422 
423 	return parse_uint(info, arg);
424 }
425 
print_possible_fields(struct field_set_info * fields)426 static void print_possible_fields(struct field_set_info *fields)
427 {
428 	struct field_set_info *ss;
429 	const char	*type, *cmd;
430 	FILE *f;
431 	char name[40], idx[40];
432 
433 	if (fields == super_fields) {
434 		type = "Superblock";
435 		cmd = "set_super_value";
436 	} else if (fields == inode_fields) {
437 		type = "Inode";
438 		cmd = "set_inode";
439 	} else {
440 		type = "Block group descriptor";
441 		cmd = "set_block_group";
442 	}
443 	f = open_pager();
444 
445 	fprintf(f, "%s fields supported by the %s command:\n", type, cmd);
446 
447 	for (ss = fields ; ss->name ; ss++) {
448 		type = "unknown";
449 		if (ss->func == parse_string)
450 			type = "string";
451 		else if (ss->func == parse_int)
452 			type = "integer";
453 		else if (ss->func == parse_uint)
454 			type = "unsigned integer";
455 		else if (ss->func == parse_uuid)
456 			type = "UUID";
457 		else if (ss->func == parse_hashalg)
458 			type = "hash algorithm";
459 		else if (ss->func == parse_time)
460 			type = "date/time";
461 		else if (ss->func == parse_bmap)
462 			type = "set physical->logical block map";
463 		strcpy(name, ss->name);
464 		if (ss->flags & FLAG_ARRAY) {
465 			if (ss->max_idx > 0)
466 				sprintf(idx, "[%d]", ss->max_idx);
467 			else
468 				strcpy(idx, "[]");
469 			strcat(name, idx);
470 		}
471 		fprintf(f, "\t%-20s\t%s\n", name, type);
472 	}
473 	close_pager(f);
474 }
475 
476 
do_set_super(int argc,char * argv[])477 void do_set_super(int argc, char *argv[])
478 {
479 	const char *usage = "<field> <value>\n"
480 		"\t\"set_super_value -l\" will list the names of "
481 		"superblock fields\n\twhich can be set.";
482 	static struct field_set_info *ss;
483 
484 	if ((argc == 2) && !strcmp(argv[1], "-l")) {
485 		print_possible_fields(super_fields);
486 		return;
487 	}
488 
489 	if (common_args_process(argc, argv, 3, 3, "set_super_value",
490 				usage, CHECK_FS_RW))
491 		return;
492 
493 	if ((ss = find_field(super_fields, argv[1])) == 0) {
494 		com_err(argv[0], 0, "invalid field specifier: %s", argv[1]);
495 		return;
496 	}
497 	set_sb = *current_fs->super;
498 	if (ss->func(ss, argv[2]) == 0) {
499 		*current_fs->super = set_sb;
500 		ext2fs_mark_super_dirty(current_fs);
501 	}
502 }
503 
do_set_inode(int argc,char * argv[])504 void do_set_inode(int argc, char *argv[])
505 {
506 	const char *usage = "<inode> <field> <value>\n"
507 		"\t\"set_inode_field -l\" will list the names of "
508 		"the fields in an ext2 inode\n\twhich can be set.";
509 	static struct field_set_info *ss;
510 
511 	if ((argc == 2) && !strcmp(argv[1], "-l")) {
512 		print_possible_fields(inode_fields);
513 		return;
514 	}
515 
516 	if (common_args_process(argc, argv, 4, 4, "set_inode",
517 				usage, CHECK_FS_RW))
518 		return;
519 
520 	if ((ss = find_field(inode_fields, argv[2])) == 0) {
521 		com_err(argv[0], 0, "invalid field specifier: %s", argv[2]);
522 		return;
523 	}
524 
525 	set_ino = string_to_inode(argv[1]);
526 	if (!set_ino)
527 		return;
528 
529 	if (debugfs_read_inode(set_ino, &set_inode, argv[1]))
530 		return;
531 
532 	if (ss->func(ss, argv[3]) == 0) {
533 		if (debugfs_write_inode(set_ino, &set_inode, argv[1]))
534 			return;
535 	}
536 }
537 
do_set_block_group_descriptor(int argc,char * argv[])538 void do_set_block_group_descriptor(int argc, char *argv[])
539 {
540 	const char *usage = "<bg number> <field> <value>\n"
541 		"\t\"set_block_group_descriptor -l\" will list the names of "
542 		"the fields in a block group descriptor\n\twhich can be set.";
543 	struct field_set_info	*ss;
544 	char			*end;
545 
546 	if ((argc == 2) && !strcmp(argv[1], "-l")) {
547 		print_possible_fields(ext2_bg_fields);
548 		return;
549 	}
550 
551 	if (common_args_process(argc, argv, 4, 4, "set_block_group_descriptor",
552 				usage, CHECK_FS_RW))
553 		return;
554 
555 	set_bg = strtoul(argv[1], &end, 0);
556 	if (*end) {
557 		com_err(argv[0], 0, "invalid block group number: %s", argv[1]);
558 		return;
559 	}
560 
561 	if (set_bg >= current_fs->group_desc_count) {
562 		com_err(argv[0], 0, "block group number too big: %d", set_bg);
563 		return;
564 	}
565 
566 
567 	if ((ss = find_field(ext2_bg_fields, argv[2])) == 0) {
568 		com_err(argv[0], 0, "invalid field specifier: %s", argv[2]);
569 		return;
570 	}
571 
572 	set_gd = current_fs->group_desc[set_bg];
573 
574 	if (ss->func(ss, argv[3]) == 0) {
575 		current_fs->group_desc[set_bg] = set_gd;
576 		ext2fs_mark_super_dirty(current_fs);
577 	}
578 }
579