xref: /linux/fs/ext2/super.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
1 /*
2  *  linux/fs/ext2/super.c
3  *
4  * Copyright (C) 1992, 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  *
9  *  from
10  *
11  *  linux/fs/minix/inode.c
12  *
13  *  Copyright (C) 1991, 1992  Linus Torvalds
14  *
15  *  Big-endian to little-endian byte-swapping/bitmaps by
16  *        David S. Miller (davem@caip.rutgers.edu), 1995
17  */
18 
19 #include <linux/config.h>
20 #include <linux/module.h>
21 #include <linux/string.h>
22 #include <linux/fs.h>
23 #include <linux/slab.h>
24 #include <linux/init.h>
25 #include <linux/blkdev.h>
26 #include <linux/parser.h>
27 #include <linux/random.h>
28 #include <linux/buffer_head.h>
29 #include <linux/smp_lock.h>
30 #include <linux/vfs.h>
31 #include <linux/seq_file.h>
32 #include <linux/mount.h>
33 #include <asm/uaccess.h>
34 #include "ext2.h"
35 #include "xattr.h"
36 #include "acl.h"
37 #include "xip.h"
38 
39 static void ext2_sync_super(struct super_block *sb,
40 			    struct ext2_super_block *es);
41 static int ext2_remount (struct super_block * sb, int * flags, char * data);
42 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf);
43 
44 void ext2_error (struct super_block * sb, const char * function,
45 		 const char * fmt, ...)
46 {
47 	va_list args;
48 	struct ext2_sb_info *sbi = EXT2_SB(sb);
49 	struct ext2_super_block *es = sbi->s_es;
50 
51 	if (!(sb->s_flags & MS_RDONLY)) {
52 		sbi->s_mount_state |= EXT2_ERROR_FS;
53 		es->s_state =
54 			cpu_to_le16(le16_to_cpu(es->s_state) | EXT2_ERROR_FS);
55 		ext2_sync_super(sb, es);
56 	}
57 
58 	va_start(args, fmt);
59 	printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
60 	vprintk(fmt, args);
61 	printk("\n");
62 	va_end(args);
63 
64 	if (test_opt(sb, ERRORS_PANIC))
65 		panic("EXT2-fs panic from previous error\n");
66 	if (test_opt(sb, ERRORS_RO)) {
67 		printk("Remounting filesystem read-only\n");
68 		sb->s_flags |= MS_RDONLY;
69 	}
70 }
71 
72 void ext2_warning (struct super_block * sb, const char * function,
73 		   const char * fmt, ...)
74 {
75 	va_list args;
76 
77 	va_start(args, fmt);
78 	printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
79 	       sb->s_id, function);
80 	vprintk(fmt, args);
81 	printk("\n");
82 	va_end(args);
83 }
84 
85 void ext2_update_dynamic_rev(struct super_block *sb)
86 {
87 	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
88 
89 	if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
90 		return;
91 
92 	ext2_warning(sb, __FUNCTION__,
93 		     "updating to rev %d because of new feature flag, "
94 		     "running e2fsck is recommended",
95 		     EXT2_DYNAMIC_REV);
96 
97 	es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
98 	es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
99 	es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
100 	/* leave es->s_feature_*compat flags alone */
101 	/* es->s_uuid will be set by e2fsck if empty */
102 
103 	/*
104 	 * The rest of the superblock fields should be zero, and if not it
105 	 * means they are likely already in use, so leave them alone.  We
106 	 * can leave it up to e2fsck to clean up any inconsistencies there.
107 	 */
108 }
109 
110 static void ext2_put_super (struct super_block * sb)
111 {
112 	int db_count;
113 	int i;
114 	struct ext2_sb_info *sbi = EXT2_SB(sb);
115 
116 	ext2_xattr_put_super(sb);
117 	if (!(sb->s_flags & MS_RDONLY)) {
118 		struct ext2_super_block *es = sbi->s_es;
119 
120 		es->s_state = cpu_to_le16(sbi->s_mount_state);
121 		ext2_sync_super(sb, es);
122 	}
123 	db_count = sbi->s_gdb_count;
124 	for (i = 0; i < db_count; i++)
125 		if (sbi->s_group_desc[i])
126 			brelse (sbi->s_group_desc[i]);
127 	kfree(sbi->s_group_desc);
128 	kfree(sbi->s_debts);
129 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
130 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
131 	percpu_counter_destroy(&sbi->s_dirs_counter);
132 	brelse (sbi->s_sbh);
133 	sb->s_fs_info = NULL;
134 	kfree(sbi);
135 
136 	return;
137 }
138 
139 static kmem_cache_t * ext2_inode_cachep;
140 
141 static struct inode *ext2_alloc_inode(struct super_block *sb)
142 {
143 	struct ext2_inode_info *ei;
144 	ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, SLAB_KERNEL);
145 	if (!ei)
146 		return NULL;
147 #ifdef CONFIG_EXT2_FS_POSIX_ACL
148 	ei->i_acl = EXT2_ACL_NOT_CACHED;
149 	ei->i_default_acl = EXT2_ACL_NOT_CACHED;
150 #endif
151 	ei->vfs_inode.i_version = 1;
152 	return &ei->vfs_inode;
153 }
154 
155 static void ext2_destroy_inode(struct inode *inode)
156 {
157 	kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
158 }
159 
160 static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
161 {
162 	struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
163 
164 	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
165 	    SLAB_CTOR_CONSTRUCTOR) {
166 		rwlock_init(&ei->i_meta_lock);
167 #ifdef CONFIG_EXT2_FS_XATTR
168 		init_rwsem(&ei->xattr_sem);
169 #endif
170 		inode_init_once(&ei->vfs_inode);
171 	}
172 }
173 
174 static int init_inodecache(void)
175 {
176 	ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
177 					     sizeof(struct ext2_inode_info),
178 					     0, (SLAB_RECLAIM_ACCOUNT|
179 						SLAB_MEM_SPREAD),
180 					     init_once, NULL);
181 	if (ext2_inode_cachep == NULL)
182 		return -ENOMEM;
183 	return 0;
184 }
185 
186 static void destroy_inodecache(void)
187 {
188 	if (kmem_cache_destroy(ext2_inode_cachep))
189 		printk(KERN_INFO "ext2_inode_cache: not all structures were freed\n");
190 }
191 
192 static void ext2_clear_inode(struct inode *inode)
193 {
194 #ifdef CONFIG_EXT2_FS_POSIX_ACL
195 	struct ext2_inode_info *ei = EXT2_I(inode);
196 
197 	if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
198 		posix_acl_release(ei->i_acl);
199 		ei->i_acl = EXT2_ACL_NOT_CACHED;
200 	}
201 	if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
202 		posix_acl_release(ei->i_default_acl);
203 		ei->i_default_acl = EXT2_ACL_NOT_CACHED;
204 	}
205 #endif
206 }
207 
208 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
209 {
210 	struct ext2_sb_info *sbi = EXT2_SB(vfs->mnt_sb);
211 
212 	if (sbi->s_mount_opt & EXT2_MOUNT_GRPID)
213 		seq_puts(seq, ",grpid");
214 
215 #if defined(CONFIG_QUOTA)
216 	if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
217 		seq_puts(seq, ",usrquota");
218 
219 	if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
220 		seq_puts(seq, ",grpquota");
221 #endif
222 
223 #if defined(CONFIG_EXT2_FS_XIP)
224 	if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
225 		seq_puts(seq, ",xip");
226 #endif
227 
228 	return 0;
229 }
230 
231 #ifdef CONFIG_QUOTA
232 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
233 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
234 #endif
235 
236 static struct super_operations ext2_sops = {
237 	.alloc_inode	= ext2_alloc_inode,
238 	.destroy_inode	= ext2_destroy_inode,
239 	.read_inode	= ext2_read_inode,
240 	.write_inode	= ext2_write_inode,
241 	.put_inode	= ext2_put_inode,
242 	.delete_inode	= ext2_delete_inode,
243 	.put_super	= ext2_put_super,
244 	.write_super	= ext2_write_super,
245 	.statfs		= ext2_statfs,
246 	.remount_fs	= ext2_remount,
247 	.clear_inode	= ext2_clear_inode,
248 	.show_options	= ext2_show_options,
249 #ifdef CONFIG_QUOTA
250 	.quota_read	= ext2_quota_read,
251 	.quota_write	= ext2_quota_write,
252 #endif
253 };
254 
255 /* Yes, most of these are left as NULL!!
256  * A NULL value implies the default, which works with ext2-like file
257  * systems, but can be improved upon.
258  * Currently only get_parent is required.
259  */
260 static struct export_operations ext2_export_ops = {
261 	.get_parent = ext2_get_parent,
262 };
263 
264 static unsigned long get_sb_block(void **data)
265 {
266 	unsigned long 	sb_block;
267 	char 		*options = (char *) *data;
268 
269 	if (!options || strncmp(options, "sb=", 3) != 0)
270 		return 1;	/* Default location */
271 	options += 3;
272 	sb_block = simple_strtoul(options, &options, 0);
273 	if (*options && *options != ',') {
274 		printk("EXT2-fs: Invalid sb specification: %s\n",
275 		       (char *) *data);
276 		return 1;
277 	}
278 	if (*options == ',')
279 		options++;
280 	*data = (void *) options;
281 	return sb_block;
282 }
283 
284 enum {
285 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
286 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
287 	Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
288 	Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
289 	Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
290 	Opt_usrquota, Opt_grpquota
291 };
292 
293 static match_table_t tokens = {
294 	{Opt_bsd_df, "bsddf"},
295 	{Opt_minix_df, "minixdf"},
296 	{Opt_grpid, "grpid"},
297 	{Opt_grpid, "bsdgroups"},
298 	{Opt_nogrpid, "nogrpid"},
299 	{Opt_nogrpid, "sysvgroups"},
300 	{Opt_resgid, "resgid=%u"},
301 	{Opt_resuid, "resuid=%u"},
302 	{Opt_sb, "sb=%u"},
303 	{Opt_err_cont, "errors=continue"},
304 	{Opt_err_panic, "errors=panic"},
305 	{Opt_err_ro, "errors=remount-ro"},
306 	{Opt_nouid32, "nouid32"},
307 	{Opt_nocheck, "check=none"},
308 	{Opt_nocheck, "nocheck"},
309 	{Opt_debug, "debug"},
310 	{Opt_oldalloc, "oldalloc"},
311 	{Opt_orlov, "orlov"},
312 	{Opt_nobh, "nobh"},
313 	{Opt_user_xattr, "user_xattr"},
314 	{Opt_nouser_xattr, "nouser_xattr"},
315 	{Opt_acl, "acl"},
316 	{Opt_noacl, "noacl"},
317 	{Opt_xip, "xip"},
318 	{Opt_grpquota, "grpquota"},
319 	{Opt_ignore, "noquota"},
320 	{Opt_quota, "quota"},
321 	{Opt_usrquota, "usrquota"},
322 	{Opt_err, NULL}
323 };
324 
325 static int parse_options (char * options,
326 			  struct ext2_sb_info *sbi)
327 {
328 	char * p;
329 	substring_t args[MAX_OPT_ARGS];
330 	unsigned long kind = EXT2_MOUNT_ERRORS_CONT;
331 	int option;
332 
333 	if (!options)
334 		return 1;
335 
336 	while ((p = strsep (&options, ",")) != NULL) {
337 		int token;
338 		if (!*p)
339 			continue;
340 
341 		token = match_token(p, tokens, args);
342 		switch (token) {
343 		case Opt_bsd_df:
344 			clear_opt (sbi->s_mount_opt, MINIX_DF);
345 			break;
346 		case Opt_minix_df:
347 			set_opt (sbi->s_mount_opt, MINIX_DF);
348 			break;
349 		case Opt_grpid:
350 			set_opt (sbi->s_mount_opt, GRPID);
351 			break;
352 		case Opt_nogrpid:
353 			clear_opt (sbi->s_mount_opt, GRPID);
354 			break;
355 		case Opt_resuid:
356 			if (match_int(&args[0], &option))
357 				return 0;
358 			sbi->s_resuid = option;
359 			break;
360 		case Opt_resgid:
361 			if (match_int(&args[0], &option))
362 				return 0;
363 			sbi->s_resgid = option;
364 			break;
365 		case Opt_sb:
366 			/* handled by get_sb_block() instead of here */
367 			/* *sb_block = match_int(&args[0]); */
368 			break;
369 		case Opt_err_panic:
370 			kind = EXT2_MOUNT_ERRORS_PANIC;
371 			break;
372 		case Opt_err_ro:
373 			kind = EXT2_MOUNT_ERRORS_RO;
374 			break;
375 		case Opt_err_cont:
376 			kind = EXT2_MOUNT_ERRORS_CONT;
377 			break;
378 		case Opt_nouid32:
379 			set_opt (sbi->s_mount_opt, NO_UID32);
380 			break;
381 		case Opt_nocheck:
382 			clear_opt (sbi->s_mount_opt, CHECK);
383 			break;
384 		case Opt_debug:
385 			set_opt (sbi->s_mount_opt, DEBUG);
386 			break;
387 		case Opt_oldalloc:
388 			set_opt (sbi->s_mount_opt, OLDALLOC);
389 			break;
390 		case Opt_orlov:
391 			clear_opt (sbi->s_mount_opt, OLDALLOC);
392 			break;
393 		case Opt_nobh:
394 			set_opt (sbi->s_mount_opt, NOBH);
395 			break;
396 #ifdef CONFIG_EXT2_FS_XATTR
397 		case Opt_user_xattr:
398 			set_opt (sbi->s_mount_opt, XATTR_USER);
399 			break;
400 		case Opt_nouser_xattr:
401 			clear_opt (sbi->s_mount_opt, XATTR_USER);
402 			break;
403 #else
404 		case Opt_user_xattr:
405 		case Opt_nouser_xattr:
406 			printk("EXT2 (no)user_xattr options not supported\n");
407 			break;
408 #endif
409 #ifdef CONFIG_EXT2_FS_POSIX_ACL
410 		case Opt_acl:
411 			set_opt(sbi->s_mount_opt, POSIX_ACL);
412 			break;
413 		case Opt_noacl:
414 			clear_opt(sbi->s_mount_opt, POSIX_ACL);
415 			break;
416 #else
417 		case Opt_acl:
418 		case Opt_noacl:
419 			printk("EXT2 (no)acl options not supported\n");
420 			break;
421 #endif
422 		case Opt_xip:
423 #ifdef CONFIG_EXT2_FS_XIP
424 			set_opt (sbi->s_mount_opt, XIP);
425 #else
426 			printk("EXT2 xip option not supported\n");
427 #endif
428 			break;
429 
430 #if defined(CONFIG_QUOTA)
431 		case Opt_quota:
432 		case Opt_usrquota:
433 			set_opt(sbi->s_mount_opt, USRQUOTA);
434 			break;
435 
436 		case Opt_grpquota:
437 			set_opt(sbi->s_mount_opt, GRPQUOTA);
438 			break;
439 #else
440 		case Opt_quota:
441 		case Opt_usrquota:
442 		case Opt_grpquota:
443 			printk(KERN_ERR
444 				"EXT2-fs: quota operations not supported.\n");
445 
446 			break;
447 #endif
448 
449 		case Opt_ignore:
450 			break;
451 		default:
452 			return 0;
453 		}
454 	}
455 	sbi->s_mount_opt |= kind;
456 	return 1;
457 }
458 
459 static int ext2_setup_super (struct super_block * sb,
460 			      struct ext2_super_block * es,
461 			      int read_only)
462 {
463 	int res = 0;
464 	struct ext2_sb_info *sbi = EXT2_SB(sb);
465 
466 	if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
467 		printk ("EXT2-fs warning: revision level too high, "
468 			"forcing read-only mode\n");
469 		res = MS_RDONLY;
470 	}
471 	if (read_only)
472 		return res;
473 	if (!(sbi->s_mount_state & EXT2_VALID_FS))
474 		printk ("EXT2-fs warning: mounting unchecked fs, "
475 			"running e2fsck is recommended\n");
476 	else if ((sbi->s_mount_state & EXT2_ERROR_FS))
477 		printk ("EXT2-fs warning: mounting fs with errors, "
478 			"running e2fsck is recommended\n");
479 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
480 		 le16_to_cpu(es->s_mnt_count) >=
481 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
482 		printk ("EXT2-fs warning: maximal mount count reached, "
483 			"running e2fsck is recommended\n");
484 	else if (le32_to_cpu(es->s_checkinterval) &&
485 		(le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
486 		printk ("EXT2-fs warning: checktime reached, "
487 			"running e2fsck is recommended\n");
488 	if (!le16_to_cpu(es->s_max_mnt_count))
489 		es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
490 	es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
491 	ext2_write_super(sb);
492 	if (test_opt (sb, DEBUG))
493 		printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
494 			"bpg=%lu, ipg=%lu, mo=%04lx]\n",
495 			EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
496 			sbi->s_frag_size,
497 			sbi->s_groups_count,
498 			EXT2_BLOCKS_PER_GROUP(sb),
499 			EXT2_INODES_PER_GROUP(sb),
500 			sbi->s_mount_opt);
501 	return res;
502 }
503 
504 static int ext2_check_descriptors (struct super_block * sb)
505 {
506 	int i;
507 	int desc_block = 0;
508 	struct ext2_sb_info *sbi = EXT2_SB(sb);
509 	unsigned long block = le32_to_cpu(sbi->s_es->s_first_data_block);
510 	struct ext2_group_desc * gdp = NULL;
511 
512 	ext2_debug ("Checking group descriptors");
513 
514 	for (i = 0; i < sbi->s_groups_count; i++)
515 	{
516 		if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
517 			gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
518 		if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
519 		    le32_to_cpu(gdp->bg_block_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
520 		{
521 			ext2_error (sb, "ext2_check_descriptors",
522 				    "Block bitmap for group %d"
523 				    " not in group (block %lu)!",
524 				    i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
525 			return 0;
526 		}
527 		if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
528 		    le32_to_cpu(gdp->bg_inode_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
529 		{
530 			ext2_error (sb, "ext2_check_descriptors",
531 				    "Inode bitmap for group %d"
532 				    " not in group (block %lu)!",
533 				    i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
534 			return 0;
535 		}
536 		if (le32_to_cpu(gdp->bg_inode_table) < block ||
537 		    le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
538 		    block + EXT2_BLOCKS_PER_GROUP(sb))
539 		{
540 			ext2_error (sb, "ext2_check_descriptors",
541 				    "Inode table for group %d"
542 				    " not in group (block %lu)!",
543 				    i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
544 			return 0;
545 		}
546 		block += EXT2_BLOCKS_PER_GROUP(sb);
547 		gdp++;
548 	}
549 	return 1;
550 }
551 
552 #define log2(n) ffz(~(n))
553 
554 /*
555  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
556  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
557  * We need to be 1 filesystem block less than the 2^32 sector limit.
558  */
559 static loff_t ext2_max_size(int bits)
560 {
561 	loff_t res = EXT2_NDIR_BLOCKS;
562 	/* This constant is calculated to be the largest file size for a
563 	 * dense, 4k-blocksize file such that the total number of
564 	 * sectors in the file, including data and all indirect blocks,
565 	 * does not exceed 2^32. */
566 	const loff_t upper_limit = 0x1ff7fffd000LL;
567 
568 	res += 1LL << (bits-2);
569 	res += 1LL << (2*(bits-2));
570 	res += 1LL << (3*(bits-2));
571 	res <<= bits;
572 	if (res > upper_limit)
573 		res = upper_limit;
574 	return res;
575 }
576 
577 static unsigned long descriptor_loc(struct super_block *sb,
578 				    unsigned long logic_sb_block,
579 				    int nr)
580 {
581 	struct ext2_sb_info *sbi = EXT2_SB(sb);
582 	unsigned long bg, first_data_block, first_meta_bg;
583 	int has_super = 0;
584 
585 	first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
586 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
587 
588 	if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
589 	    nr < first_meta_bg)
590 		return (logic_sb_block + nr + 1);
591 	bg = sbi->s_desc_per_block * nr;
592 	if (ext2_bg_has_super(sb, bg))
593 		has_super = 1;
594 	return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
595 }
596 
597 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
598 {
599 	struct buffer_head * bh;
600 	struct ext2_sb_info * sbi;
601 	struct ext2_super_block * es;
602 	struct inode *root;
603 	unsigned long block;
604 	unsigned long sb_block = get_sb_block(&data);
605 	unsigned long logic_sb_block;
606 	unsigned long offset = 0;
607 	unsigned long def_mount_opts;
608 	int blocksize = BLOCK_SIZE;
609 	int db_count;
610 	int i, j;
611 	__le32 features;
612 
613 	sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
614 	if (!sbi)
615 		return -ENOMEM;
616 	sb->s_fs_info = sbi;
617 	memset(sbi, 0, sizeof(*sbi));
618 
619 	/*
620 	 * See what the current blocksize for the device is, and
621 	 * use that as the blocksize.  Otherwise (or if the blocksize
622 	 * is smaller than the default) use the default.
623 	 * This is important for devices that have a hardware
624 	 * sectorsize that is larger than the default.
625 	 */
626 	blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
627 	if (!blocksize) {
628 		printk ("EXT2-fs: unable to set blocksize\n");
629 		goto failed_sbi;
630 	}
631 
632 	/*
633 	 * If the superblock doesn't start on a hardware sector boundary,
634 	 * calculate the offset.
635 	 */
636 	if (blocksize != BLOCK_SIZE) {
637 		logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
638 		offset = (sb_block*BLOCK_SIZE) % blocksize;
639 	} else {
640 		logic_sb_block = sb_block;
641 	}
642 
643 	if (!(bh = sb_bread(sb, logic_sb_block))) {
644 		printk ("EXT2-fs: unable to read superblock\n");
645 		goto failed_sbi;
646 	}
647 	/*
648 	 * Note: s_es must be initialized as soon as possible because
649 	 *       some ext2 macro-instructions depend on its value
650 	 */
651 	es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
652 	sbi->s_es = es;
653 	sb->s_magic = le16_to_cpu(es->s_magic);
654 
655 	if (sb->s_magic != EXT2_SUPER_MAGIC)
656 		goto cantfind_ext2;
657 
658 	/* Set defaults before we parse the mount options */
659 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
660 	if (def_mount_opts & EXT2_DEFM_DEBUG)
661 		set_opt(sbi->s_mount_opt, DEBUG);
662 	if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
663 		set_opt(sbi->s_mount_opt, GRPID);
664 	if (def_mount_opts & EXT2_DEFM_UID16)
665 		set_opt(sbi->s_mount_opt, NO_UID32);
666 	if (def_mount_opts & EXT2_DEFM_XATTR_USER)
667 		set_opt(sbi->s_mount_opt, XATTR_USER);
668 	if (def_mount_opts & EXT2_DEFM_ACL)
669 		set_opt(sbi->s_mount_opt, POSIX_ACL);
670 
671 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
672 		set_opt(sbi->s_mount_opt, ERRORS_PANIC);
673 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
674 		set_opt(sbi->s_mount_opt, ERRORS_RO);
675 
676 	sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
677 	sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
678 
679 	if (!parse_options ((char *) data, sbi))
680 		goto failed_mount;
681 
682 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
683 		((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
684 		 MS_POSIXACL : 0);
685 
686 	ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
687 				    EXT2_MOUNT_XIP if not */
688 
689 	if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
690 	    (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
691 	     EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
692 	     EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
693 		printk("EXT2-fs warning: feature flags set on rev 0 fs, "
694 		       "running e2fsck is recommended\n");
695 	/*
696 	 * Check feature flags regardless of the revision level, since we
697 	 * previously didn't change the revision level when setting the flags,
698 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
699 	 */
700 	features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
701 	if (features) {
702 		printk("EXT2-fs: %s: couldn't mount because of "
703 		       "unsupported optional features (%x).\n",
704 		       sb->s_id, le32_to_cpu(features));
705 		goto failed_mount;
706 	}
707 	if (!(sb->s_flags & MS_RDONLY) &&
708 	    (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
709 		printk("EXT2-fs: %s: couldn't mount RDWR because of "
710 		       "unsupported optional features (%x).\n",
711 		       sb->s_id, le32_to_cpu(features));
712 		goto failed_mount;
713 	}
714 
715 	blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
716 
717 	if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
718 				  (sb->s_blocksize != blocksize))) {
719 		if (!silent)
720 			printk("XIP: Unsupported blocksize\n");
721 		goto failed_mount;
722 	}
723 
724 	/* If the blocksize doesn't match, re-read the thing.. */
725 	if (sb->s_blocksize != blocksize) {
726 		brelse(bh);
727 
728 		if (!sb_set_blocksize(sb, blocksize)) {
729 			printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
730 			goto failed_sbi;
731 		}
732 
733 		logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
734 		offset = (sb_block*BLOCK_SIZE) % blocksize;
735 		bh = sb_bread(sb, logic_sb_block);
736 		if(!bh) {
737 			printk("EXT2-fs: Couldn't read superblock on "
738 			       "2nd try.\n");
739 			goto failed_sbi;
740 		}
741 		es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
742 		sbi->s_es = es;
743 		if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
744 			printk ("EXT2-fs: Magic mismatch, very weird !\n");
745 			goto failed_mount;
746 		}
747 	}
748 
749 	sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
750 
751 	if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
752 		sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
753 		sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
754 	} else {
755 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
756 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
757 		if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
758 		    (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
759 		    (sbi->s_inode_size > blocksize)) {
760 			printk ("EXT2-fs: unsupported inode size: %d\n",
761 				sbi->s_inode_size);
762 			goto failed_mount;
763 		}
764 	}
765 
766 	sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
767 				   le32_to_cpu(es->s_log_frag_size);
768 	if (sbi->s_frag_size == 0)
769 		goto cantfind_ext2;
770 	sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
771 
772 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
773 	sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
774 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
775 
776 	if (EXT2_INODE_SIZE(sb) == 0)
777 		goto cantfind_ext2;
778 	sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
779 	if (sbi->s_inodes_per_block == 0)
780 		goto cantfind_ext2;
781 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
782 					sbi->s_inodes_per_block;
783 	sbi->s_desc_per_block = sb->s_blocksize /
784 					sizeof (struct ext2_group_desc);
785 	sbi->s_sbh = bh;
786 	sbi->s_mount_state = le16_to_cpu(es->s_state);
787 	sbi->s_addr_per_block_bits =
788 		log2 (EXT2_ADDR_PER_BLOCK(sb));
789 	sbi->s_desc_per_block_bits =
790 		log2 (EXT2_DESC_PER_BLOCK(sb));
791 
792 	if (sb->s_magic != EXT2_SUPER_MAGIC)
793 		goto cantfind_ext2;
794 
795 	if (sb->s_blocksize != bh->b_size) {
796 		if (!silent)
797 			printk ("VFS: Unsupported blocksize on dev "
798 				"%s.\n", sb->s_id);
799 		goto failed_mount;
800 	}
801 
802 	if (sb->s_blocksize != sbi->s_frag_size) {
803 		printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
804 			sbi->s_frag_size, sb->s_blocksize);
805 		goto failed_mount;
806 	}
807 
808 	if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
809 		printk ("EXT2-fs: #blocks per group too big: %lu\n",
810 			sbi->s_blocks_per_group);
811 		goto failed_mount;
812 	}
813 	if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
814 		printk ("EXT2-fs: #fragments per group too big: %lu\n",
815 			sbi->s_frags_per_group);
816 		goto failed_mount;
817 	}
818 	if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
819 		printk ("EXT2-fs: #inodes per group too big: %lu\n",
820 			sbi->s_inodes_per_group);
821 		goto failed_mount;
822 	}
823 
824 	if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
825 		goto cantfind_ext2;
826 	sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
827 				        le32_to_cpu(es->s_first_data_block) +
828 				       EXT2_BLOCKS_PER_GROUP(sb) - 1) /
829 				       EXT2_BLOCKS_PER_GROUP(sb);
830 	db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
831 		   EXT2_DESC_PER_BLOCK(sb);
832 	sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
833 	if (sbi->s_group_desc == NULL) {
834 		printk ("EXT2-fs: not enough memory\n");
835 		goto failed_mount;
836 	}
837 	percpu_counter_init(&sbi->s_freeblocks_counter);
838 	percpu_counter_init(&sbi->s_freeinodes_counter);
839 	percpu_counter_init(&sbi->s_dirs_counter);
840 	bgl_lock_init(&sbi->s_blockgroup_lock);
841 	sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
842 			       GFP_KERNEL);
843 	if (!sbi->s_debts) {
844 		printk ("EXT2-fs: not enough memory\n");
845 		goto failed_mount_group_desc;
846 	}
847 	memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
848 	for (i = 0; i < db_count; i++) {
849 		block = descriptor_loc(sb, logic_sb_block, i);
850 		sbi->s_group_desc[i] = sb_bread(sb, block);
851 		if (!sbi->s_group_desc[i]) {
852 			for (j = 0; j < i; j++)
853 				brelse (sbi->s_group_desc[j]);
854 			printk ("EXT2-fs: unable to read group descriptors\n");
855 			goto failed_mount_group_desc;
856 		}
857 	}
858 	if (!ext2_check_descriptors (sb)) {
859 		printk ("EXT2-fs: group descriptors corrupted!\n");
860 		db_count = i;
861 		goto failed_mount2;
862 	}
863 	sbi->s_gdb_count = db_count;
864 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
865 	spin_lock_init(&sbi->s_next_gen_lock);
866 	/*
867 	 * set up enough so that it can read an inode
868 	 */
869 	sb->s_op = &ext2_sops;
870 	sb->s_export_op = &ext2_export_ops;
871 	sb->s_xattr = ext2_xattr_handlers;
872 	root = iget(sb, EXT2_ROOT_INO);
873 	sb->s_root = d_alloc_root(root);
874 	if (!sb->s_root) {
875 		iput(root);
876 		printk(KERN_ERR "EXT2-fs: get root inode failed\n");
877 		goto failed_mount2;
878 	}
879 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
880 		dput(sb->s_root);
881 		sb->s_root = NULL;
882 		printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
883 		goto failed_mount2;
884 	}
885 	if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
886 		ext2_warning(sb, __FUNCTION__,
887 			"mounting ext3 filesystem as ext2");
888 	ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
889 	percpu_counter_mod(&sbi->s_freeblocks_counter,
890 				ext2_count_free_blocks(sb));
891 	percpu_counter_mod(&sbi->s_freeinodes_counter,
892 				ext2_count_free_inodes(sb));
893 	percpu_counter_mod(&sbi->s_dirs_counter,
894 				ext2_count_dirs(sb));
895 	return 0;
896 
897 cantfind_ext2:
898 	if (!silent)
899 		printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
900 		       sb->s_id);
901 	goto failed_mount;
902 
903 failed_mount2:
904 	for (i = 0; i < db_count; i++)
905 		brelse(sbi->s_group_desc[i]);
906 failed_mount_group_desc:
907 	kfree(sbi->s_group_desc);
908 	kfree(sbi->s_debts);
909 failed_mount:
910 	brelse(bh);
911 failed_sbi:
912 	sb->s_fs_info = NULL;
913 	kfree(sbi);
914 	return -EINVAL;
915 }
916 
917 static void ext2_commit_super (struct super_block * sb,
918 			       struct ext2_super_block * es)
919 {
920 	es->s_wtime = cpu_to_le32(get_seconds());
921 	mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
922 	sb->s_dirt = 0;
923 }
924 
925 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
926 {
927 	es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
928 	es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
929 	es->s_wtime = cpu_to_le32(get_seconds());
930 	mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
931 	sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
932 	sb->s_dirt = 0;
933 }
934 
935 /*
936  * In the second extended file system, it is not necessary to
937  * write the super block since we use a mapping of the
938  * disk super block in a buffer.
939  *
940  * However, this function is still used to set the fs valid
941  * flags to 0.  We need to set this flag to 0 since the fs
942  * may have been checked while mounted and e2fsck may have
943  * set s_state to EXT2_VALID_FS after some corrections.
944  */
945 
946 void ext2_write_super (struct super_block * sb)
947 {
948 	struct ext2_super_block * es;
949 	lock_kernel();
950 	if (!(sb->s_flags & MS_RDONLY)) {
951 		es = EXT2_SB(sb)->s_es;
952 
953 		if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
954 			ext2_debug ("setting valid to 0\n");
955 			es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
956 						  ~EXT2_VALID_FS);
957 			es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
958 			es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
959 			es->s_mtime = cpu_to_le32(get_seconds());
960 			ext2_sync_super(sb, es);
961 		} else
962 			ext2_commit_super (sb, es);
963 	}
964 	sb->s_dirt = 0;
965 	unlock_kernel();
966 }
967 
968 static int ext2_remount (struct super_block * sb, int * flags, char * data)
969 {
970 	struct ext2_sb_info * sbi = EXT2_SB(sb);
971 	struct ext2_super_block * es;
972 	unsigned long old_mount_opt = sbi->s_mount_opt;
973 	struct ext2_mount_options old_opts;
974 	unsigned long old_sb_flags;
975 	int err;
976 
977 	/* Store the old options */
978 	old_sb_flags = sb->s_flags;
979 	old_opts.s_mount_opt = sbi->s_mount_opt;
980 	old_opts.s_resuid = sbi->s_resuid;
981 	old_opts.s_resgid = sbi->s_resgid;
982 
983 	/*
984 	 * Allow the "check" option to be passed as a remount option.
985 	 */
986 	if (!parse_options (data, sbi)) {
987 		err = -EINVAL;
988 		goto restore_opts;
989 	}
990 
991 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
992 		((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
993 
994 	es = sbi->s_es;
995 	if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
996 	    (old_mount_opt & EXT2_MOUNT_XIP)) &&
997 	    invalidate_inodes(sb))
998 		ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
999 			     "xip remain in cache (no functional problem)");
1000 	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1001 		return 0;
1002 	if (*flags & MS_RDONLY) {
1003 		if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1004 		    !(sbi->s_mount_state & EXT2_VALID_FS))
1005 			return 0;
1006 		/*
1007 		 * OK, we are remounting a valid rw partition rdonly, so set
1008 		 * the rdonly flag and then mark the partition as valid again.
1009 		 */
1010 		es->s_state = cpu_to_le16(sbi->s_mount_state);
1011 		es->s_mtime = cpu_to_le32(get_seconds());
1012 	} else {
1013 		__le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1014 					       ~EXT2_FEATURE_RO_COMPAT_SUPP);
1015 		if (ret) {
1016 			printk("EXT2-fs: %s: couldn't remount RDWR because of "
1017 			       "unsupported optional features (%x).\n",
1018 			       sb->s_id, le32_to_cpu(ret));
1019 			err = -EROFS;
1020 			goto restore_opts;
1021 		}
1022 		/*
1023 		 * Mounting a RDONLY partition read-write, so reread and
1024 		 * store the current valid flag.  (It may have been changed
1025 		 * by e2fsck since we originally mounted the partition.)
1026 		 */
1027 		sbi->s_mount_state = le16_to_cpu(es->s_state);
1028 		if (!ext2_setup_super (sb, es, 0))
1029 			sb->s_flags &= ~MS_RDONLY;
1030 	}
1031 	ext2_sync_super(sb, es);
1032 	return 0;
1033 restore_opts:
1034 	sbi->s_mount_opt = old_opts.s_mount_opt;
1035 	sbi->s_resuid = old_opts.s_resuid;
1036 	sbi->s_resgid = old_opts.s_resgid;
1037 	sb->s_flags = old_sb_flags;
1038 	return err;
1039 }
1040 
1041 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf)
1042 {
1043 	struct ext2_sb_info *sbi = EXT2_SB(sb);
1044 	unsigned long overhead;
1045 	int i;
1046 
1047 	if (test_opt (sb, MINIX_DF))
1048 		overhead = 0;
1049 	else {
1050 		/*
1051 		 * Compute the overhead (FS structures)
1052 		 */
1053 
1054 		/*
1055 		 * All of the blocks before first_data_block are
1056 		 * overhead
1057 		 */
1058 		overhead = le32_to_cpu(sbi->s_es->s_first_data_block);
1059 
1060 		/*
1061 		 * Add the overhead attributed to the superblock and
1062 		 * block group descriptors.  If the sparse superblocks
1063 		 * feature is turned on, then not all groups have this.
1064 		 */
1065 		for (i = 0; i < sbi->s_groups_count; i++)
1066 			overhead += ext2_bg_has_super(sb, i) +
1067 				ext2_bg_num_gdb(sb, i);
1068 
1069 		/*
1070 		 * Every block group has an inode bitmap, a block
1071 		 * bitmap, and an inode table.
1072 		 */
1073 		overhead += (sbi->s_groups_count *
1074 			     (2 + sbi->s_itb_per_group));
1075 	}
1076 
1077 	buf->f_type = EXT2_SUPER_MAGIC;
1078 	buf->f_bsize = sb->s_blocksize;
1079 	buf->f_blocks = le32_to_cpu(sbi->s_es->s_blocks_count) - overhead;
1080 	buf->f_bfree = ext2_count_free_blocks(sb);
1081 	buf->f_bavail = buf->f_bfree - le32_to_cpu(sbi->s_es->s_r_blocks_count);
1082 	if (buf->f_bfree < le32_to_cpu(sbi->s_es->s_r_blocks_count))
1083 		buf->f_bavail = 0;
1084 	buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
1085 	buf->f_ffree = ext2_count_free_inodes (sb);
1086 	buf->f_namelen = EXT2_NAME_LEN;
1087 	return 0;
1088 }
1089 
1090 static struct super_block *ext2_get_sb(struct file_system_type *fs_type,
1091 	int flags, const char *dev_name, void *data)
1092 {
1093 	return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1094 }
1095 
1096 #ifdef CONFIG_QUOTA
1097 
1098 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1099  * acquiring the locks... As quota files are never truncated and quota code
1100  * itself serializes the operations (and noone else should touch the files)
1101  * we don't have to be afraid of races */
1102 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1103 			       size_t len, loff_t off)
1104 {
1105 	struct inode *inode = sb_dqopt(sb)->files[type];
1106 	sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1107 	int err = 0;
1108 	int offset = off & (sb->s_blocksize - 1);
1109 	int tocopy;
1110 	size_t toread;
1111 	struct buffer_head tmp_bh;
1112 	struct buffer_head *bh;
1113 	loff_t i_size = i_size_read(inode);
1114 
1115 	if (off > i_size)
1116 		return 0;
1117 	if (off+len > i_size)
1118 		len = i_size-off;
1119 	toread = len;
1120 	while (toread > 0) {
1121 		tocopy = sb->s_blocksize - offset < toread ?
1122 				sb->s_blocksize - offset : toread;
1123 
1124 		tmp_bh.b_state = 0;
1125 		err = ext2_get_block(inode, blk, &tmp_bh, 0);
1126 		if (err)
1127 			return err;
1128 		if (!buffer_mapped(&tmp_bh))	/* A hole? */
1129 			memset(data, 0, tocopy);
1130 		else {
1131 			bh = sb_bread(sb, tmp_bh.b_blocknr);
1132 			if (!bh)
1133 				return -EIO;
1134 			memcpy(data, bh->b_data+offset, tocopy);
1135 			brelse(bh);
1136 		}
1137 		offset = 0;
1138 		toread -= tocopy;
1139 		data += tocopy;
1140 		blk++;
1141 	}
1142 	return len;
1143 }
1144 
1145 /* Write to quotafile */
1146 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1147 				const char *data, size_t len, loff_t off)
1148 {
1149 	struct inode *inode = sb_dqopt(sb)->files[type];
1150 	sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1151 	int err = 0;
1152 	int offset = off & (sb->s_blocksize - 1);
1153 	int tocopy;
1154 	size_t towrite = len;
1155 	struct buffer_head tmp_bh;
1156 	struct buffer_head *bh;
1157 
1158 	mutex_lock(&inode->i_mutex);
1159 	while (towrite > 0) {
1160 		tocopy = sb->s_blocksize - offset < towrite ?
1161 				sb->s_blocksize - offset : towrite;
1162 
1163 		tmp_bh.b_state = 0;
1164 		err = ext2_get_block(inode, blk, &tmp_bh, 1);
1165 		if (err)
1166 			goto out;
1167 		if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1168 			bh = sb_bread(sb, tmp_bh.b_blocknr);
1169 		else
1170 			bh = sb_getblk(sb, tmp_bh.b_blocknr);
1171 		if (!bh) {
1172 			err = -EIO;
1173 			goto out;
1174 		}
1175 		lock_buffer(bh);
1176 		memcpy(bh->b_data+offset, data, tocopy);
1177 		flush_dcache_page(bh->b_page);
1178 		set_buffer_uptodate(bh);
1179 		mark_buffer_dirty(bh);
1180 		unlock_buffer(bh);
1181 		brelse(bh);
1182 		offset = 0;
1183 		towrite -= tocopy;
1184 		data += tocopy;
1185 		blk++;
1186 	}
1187 out:
1188 	if (len == towrite)
1189 		return err;
1190 	if (inode->i_size < off+len-towrite)
1191 		i_size_write(inode, off+len-towrite);
1192 	inode->i_version++;
1193 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1194 	mark_inode_dirty(inode);
1195 	mutex_unlock(&inode->i_mutex);
1196 	return len - towrite;
1197 }
1198 
1199 #endif
1200 
1201 static struct file_system_type ext2_fs_type = {
1202 	.owner		= THIS_MODULE,
1203 	.name		= "ext2",
1204 	.get_sb		= ext2_get_sb,
1205 	.kill_sb	= kill_block_super,
1206 	.fs_flags	= FS_REQUIRES_DEV,
1207 };
1208 
1209 static int __init init_ext2_fs(void)
1210 {
1211 	int err = init_ext2_xattr();
1212 	if (err)
1213 		return err;
1214 	err = init_inodecache();
1215 	if (err)
1216 		goto out1;
1217         err = register_filesystem(&ext2_fs_type);
1218 	if (err)
1219 		goto out;
1220 	return 0;
1221 out:
1222 	destroy_inodecache();
1223 out1:
1224 	exit_ext2_xattr();
1225 	return err;
1226 }
1227 
1228 static void __exit exit_ext2_fs(void)
1229 {
1230 	unregister_filesystem(&ext2_fs_type);
1231 	destroy_inodecache();
1232 	exit_ext2_xattr();
1233 }
1234 
1235 module_init(init_ext2_fs)
1236 module_exit(exit_ext2_fs)
1237