xref: /openbmc/linux/fs/ext2/super.c (revision 6f69e2a3)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  linux/fs/ext2/super.c
4  *
5  * Copyright (C) 1992, 1993, 1994, 1995
6  * Remy Card (card@masi.ibp.fr)
7  * Laboratoire MASI - Institut Blaise Pascal
8  * Universite Pierre et Marie Curie (Paris VI)
9  *
10  *  from
11  *
12  *  linux/fs/minix/inode.c
13  *
14  *  Copyright (C) 1991, 1992  Linus Torvalds
15  *
16  *  Big-endian to little-endian byte-swapping/bitmaps by
17  *        David S. Miller (davem@caip.rutgers.edu), 1995
18  */
19 
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/exportfs.h>
30 #include <linux/vfs.h>
31 #include <linux/seq_file.h>
32 #include <linux/mount.h>
33 #include <linux/log2.h>
34 #include <linux/quotaops.h>
35 #include <linux/uaccess.h>
36 #include <linux/dax.h>
37 #include <linux/iversion.h>
38 #include "ext2.h"
39 #include "xattr.h"
40 #include "acl.h"
41 
42 static void ext2_write_super(struct super_block *sb);
43 static int ext2_remount (struct super_block * sb, int * flags, char * data);
44 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
45 static int ext2_sync_fs(struct super_block *sb, int wait);
46 static int ext2_freeze(struct super_block *sb);
47 static int ext2_unfreeze(struct super_block *sb);
48 
49 void ext2_error(struct super_block *sb, const char *function,
50 		const char *fmt, ...)
51 {
52 	struct va_format vaf;
53 	va_list args;
54 	struct ext2_sb_info *sbi = EXT2_SB(sb);
55 	struct ext2_super_block *es = sbi->s_es;
56 
57 	if (!sb_rdonly(sb)) {
58 		spin_lock(&sbi->s_lock);
59 		sbi->s_mount_state |= EXT2_ERROR_FS;
60 		es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
61 		spin_unlock(&sbi->s_lock);
62 		ext2_sync_super(sb, es, 1);
63 	}
64 
65 	va_start(args, fmt);
66 
67 	vaf.fmt = fmt;
68 	vaf.va = &args;
69 
70 	printk(KERN_CRIT "EXT2-fs (%s): error: %s: %pV\n",
71 	       sb->s_id, function, &vaf);
72 
73 	va_end(args);
74 
75 	if (test_opt(sb, ERRORS_PANIC))
76 		panic("EXT2-fs: panic from previous error\n");
77 	if (!sb_rdonly(sb) && test_opt(sb, ERRORS_RO)) {
78 		ext2_msg(sb, KERN_CRIT,
79 			     "error: remounting filesystem read-only");
80 		sb->s_flags |= SB_RDONLY;
81 	}
82 }
83 
84 void ext2_msg(struct super_block *sb, const char *prefix,
85 		const char *fmt, ...)
86 {
87 	struct va_format vaf;
88 	va_list args;
89 
90 	va_start(args, fmt);
91 
92 	vaf.fmt = fmt;
93 	vaf.va = &args;
94 
95 	printk("%sEXT2-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
96 
97 	va_end(args);
98 }
99 
100 /*
101  * This must be called with sbi->s_lock held.
102  */
103 void ext2_update_dynamic_rev(struct super_block *sb)
104 {
105 	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
106 
107 	if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
108 		return;
109 
110 	ext2_msg(sb, KERN_WARNING,
111 		     "warning: updating to rev %d because of "
112 		     "new feature flag, running e2fsck is recommended",
113 		     EXT2_DYNAMIC_REV);
114 
115 	es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
116 	es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
117 	es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
118 	/* leave es->s_feature_*compat flags alone */
119 	/* es->s_uuid will be set by e2fsck if empty */
120 
121 	/*
122 	 * The rest of the superblock fields should be zero, and if not it
123 	 * means they are likely already in use, so leave them alone.  We
124 	 * can leave it up to e2fsck to clean up any inconsistencies there.
125 	 */
126 }
127 
128 #ifdef CONFIG_QUOTA
129 static int ext2_quota_off(struct super_block *sb, int type);
130 
131 static void ext2_quota_off_umount(struct super_block *sb)
132 {
133 	int type;
134 
135 	for (type = 0; type < MAXQUOTAS; type++)
136 		ext2_quota_off(sb, type);
137 }
138 #else
139 static inline void ext2_quota_off_umount(struct super_block *sb)
140 {
141 }
142 #endif
143 
144 static void ext2_put_super (struct super_block * sb)
145 {
146 	int db_count;
147 	int i;
148 	struct ext2_sb_info *sbi = EXT2_SB(sb);
149 
150 	ext2_quota_off_umount(sb);
151 
152 	ext2_xattr_destroy_cache(sbi->s_ea_block_cache);
153 	sbi->s_ea_block_cache = NULL;
154 
155 	if (!sb_rdonly(sb)) {
156 		struct ext2_super_block *es = sbi->s_es;
157 
158 		spin_lock(&sbi->s_lock);
159 		es->s_state = cpu_to_le16(sbi->s_mount_state);
160 		spin_unlock(&sbi->s_lock);
161 		ext2_sync_super(sb, es, 1);
162 	}
163 	db_count = sbi->s_gdb_count;
164 	for (i = 0; i < db_count; i++)
165 		brelse(sbi->s_group_desc[i]);
166 	kfree(sbi->s_group_desc);
167 	kfree(sbi->s_debts);
168 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
169 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
170 	percpu_counter_destroy(&sbi->s_dirs_counter);
171 	brelse (sbi->s_sbh);
172 	sb->s_fs_info = NULL;
173 	kfree(sbi->s_blockgroup_lock);
174 	fs_put_dax(sbi->s_daxdev);
175 	kfree(sbi);
176 }
177 
178 static struct kmem_cache * ext2_inode_cachep;
179 
180 static struct inode *ext2_alloc_inode(struct super_block *sb)
181 {
182 	struct ext2_inode_info *ei;
183 	ei = kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
184 	if (!ei)
185 		return NULL;
186 	ei->i_block_alloc_info = NULL;
187 	inode_set_iversion(&ei->vfs_inode, 1);
188 #ifdef CONFIG_QUOTA
189 	memset(&ei->i_dquot, 0, sizeof(ei->i_dquot));
190 #endif
191 
192 	return &ei->vfs_inode;
193 }
194 
195 static void ext2_free_in_core_inode(struct inode *inode)
196 {
197 	kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
198 }
199 
200 static void init_once(void *foo)
201 {
202 	struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
203 
204 	rwlock_init(&ei->i_meta_lock);
205 #ifdef CONFIG_EXT2_FS_XATTR
206 	init_rwsem(&ei->xattr_sem);
207 #endif
208 	mutex_init(&ei->truncate_mutex);
209 #ifdef CONFIG_FS_DAX
210 	init_rwsem(&ei->dax_sem);
211 #endif
212 	inode_init_once(&ei->vfs_inode);
213 }
214 
215 static int __init init_inodecache(void)
216 {
217 	ext2_inode_cachep = kmem_cache_create_usercopy("ext2_inode_cache",
218 				sizeof(struct ext2_inode_info), 0,
219 				(SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
220 					SLAB_ACCOUNT),
221 				offsetof(struct ext2_inode_info, i_data),
222 				sizeof_field(struct ext2_inode_info, i_data),
223 				init_once);
224 	if (ext2_inode_cachep == NULL)
225 		return -ENOMEM;
226 	return 0;
227 }
228 
229 static void destroy_inodecache(void)
230 {
231 	/*
232 	 * Make sure all delayed rcu free inodes are flushed before we
233 	 * destroy cache.
234 	 */
235 	rcu_barrier();
236 	kmem_cache_destroy(ext2_inode_cachep);
237 }
238 
239 static int ext2_show_options(struct seq_file *seq, struct dentry *root)
240 {
241 	struct super_block *sb = root->d_sb;
242 	struct ext2_sb_info *sbi = EXT2_SB(sb);
243 	struct ext2_super_block *es = sbi->s_es;
244 	unsigned long def_mount_opts;
245 
246 	spin_lock(&sbi->s_lock);
247 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
248 
249 	if (sbi->s_sb_block != 1)
250 		seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
251 	if (test_opt(sb, MINIX_DF))
252 		seq_puts(seq, ",minixdf");
253 	if (test_opt(sb, GRPID))
254 		seq_puts(seq, ",grpid");
255 	if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
256 		seq_puts(seq, ",nogrpid");
257 	if (!uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT2_DEF_RESUID)) ||
258 	    le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
259 		seq_printf(seq, ",resuid=%u",
260 				from_kuid_munged(&init_user_ns, sbi->s_resuid));
261 	}
262 	if (!gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT2_DEF_RESGID)) ||
263 	    le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
264 		seq_printf(seq, ",resgid=%u",
265 				from_kgid_munged(&init_user_ns, sbi->s_resgid));
266 	}
267 	if (test_opt(sb, ERRORS_RO)) {
268 		int def_errors = le16_to_cpu(es->s_errors);
269 
270 		if (def_errors == EXT2_ERRORS_PANIC ||
271 		    def_errors == EXT2_ERRORS_CONTINUE) {
272 			seq_puts(seq, ",errors=remount-ro");
273 		}
274 	}
275 	if (test_opt(sb, ERRORS_CONT))
276 		seq_puts(seq, ",errors=continue");
277 	if (test_opt(sb, ERRORS_PANIC))
278 		seq_puts(seq, ",errors=panic");
279 	if (test_opt(sb, NO_UID32))
280 		seq_puts(seq, ",nouid32");
281 	if (test_opt(sb, DEBUG))
282 		seq_puts(seq, ",debug");
283 	if (test_opt(sb, OLDALLOC))
284 		seq_puts(seq, ",oldalloc");
285 
286 #ifdef CONFIG_EXT2_FS_XATTR
287 	if (test_opt(sb, XATTR_USER))
288 		seq_puts(seq, ",user_xattr");
289 	if (!test_opt(sb, XATTR_USER) &&
290 	    (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
291 		seq_puts(seq, ",nouser_xattr");
292 	}
293 #endif
294 
295 #ifdef CONFIG_EXT2_FS_POSIX_ACL
296 	if (test_opt(sb, POSIX_ACL))
297 		seq_puts(seq, ",acl");
298 	if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
299 		seq_puts(seq, ",noacl");
300 #endif
301 
302 	if (test_opt(sb, NOBH))
303 		seq_puts(seq, ",nobh");
304 
305 	if (test_opt(sb, USRQUOTA))
306 		seq_puts(seq, ",usrquota");
307 
308 	if (test_opt(sb, GRPQUOTA))
309 		seq_puts(seq, ",grpquota");
310 
311 	if (test_opt(sb, XIP))
312 		seq_puts(seq, ",xip");
313 
314 	if (test_opt(sb, DAX))
315 		seq_puts(seq, ",dax");
316 
317 	if (!test_opt(sb, RESERVATION))
318 		seq_puts(seq, ",noreservation");
319 
320 	spin_unlock(&sbi->s_lock);
321 	return 0;
322 }
323 
324 #ifdef CONFIG_QUOTA
325 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
326 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
327 static int ext2_quota_on(struct super_block *sb, int type, int format_id,
328 			 const struct path *path);
329 static struct dquot **ext2_get_dquots(struct inode *inode)
330 {
331 	return EXT2_I(inode)->i_dquot;
332 }
333 
334 static const struct quotactl_ops ext2_quotactl_ops = {
335 	.quota_on	= ext2_quota_on,
336 	.quota_off	= ext2_quota_off,
337 	.quota_sync	= dquot_quota_sync,
338 	.get_state	= dquot_get_state,
339 	.set_info	= dquot_set_dqinfo,
340 	.get_dqblk	= dquot_get_dqblk,
341 	.set_dqblk	= dquot_set_dqblk,
342 	.get_nextdqblk	= dquot_get_next_dqblk,
343 };
344 #endif
345 
346 static const struct super_operations ext2_sops = {
347 	.alloc_inode	= ext2_alloc_inode,
348 	.free_inode	= ext2_free_in_core_inode,
349 	.write_inode	= ext2_write_inode,
350 	.evict_inode	= ext2_evict_inode,
351 	.put_super	= ext2_put_super,
352 	.sync_fs	= ext2_sync_fs,
353 	.freeze_fs	= ext2_freeze,
354 	.unfreeze_fs	= ext2_unfreeze,
355 	.statfs		= ext2_statfs,
356 	.remount_fs	= ext2_remount,
357 	.show_options	= ext2_show_options,
358 #ifdef CONFIG_QUOTA
359 	.quota_read	= ext2_quota_read,
360 	.quota_write	= ext2_quota_write,
361 	.get_dquots	= ext2_get_dquots,
362 #endif
363 };
364 
365 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
366 		u64 ino, u32 generation)
367 {
368 	struct inode *inode;
369 
370 	if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
371 		return ERR_PTR(-ESTALE);
372 	if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
373 		return ERR_PTR(-ESTALE);
374 
375 	/*
376 	 * ext2_iget isn't quite right if the inode is currently unallocated!
377 	 * However ext2_iget currently does appropriate checks to handle stale
378 	 * inodes so everything is OK.
379 	 */
380 	inode = ext2_iget(sb, ino);
381 	if (IS_ERR(inode))
382 		return ERR_CAST(inode);
383 	if (generation && inode->i_generation != generation) {
384 		/* we didn't find the right inode.. */
385 		iput(inode);
386 		return ERR_PTR(-ESTALE);
387 	}
388 	return inode;
389 }
390 
391 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
392 		int fh_len, int fh_type)
393 {
394 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
395 				    ext2_nfs_get_inode);
396 }
397 
398 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
399 		int fh_len, int fh_type)
400 {
401 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
402 				    ext2_nfs_get_inode);
403 }
404 
405 static const struct export_operations ext2_export_ops = {
406 	.fh_to_dentry = ext2_fh_to_dentry,
407 	.fh_to_parent = ext2_fh_to_parent,
408 	.get_parent = ext2_get_parent,
409 };
410 
411 static unsigned long get_sb_block(void **data)
412 {
413 	unsigned long 	sb_block;
414 	char 		*options = (char *) *data;
415 
416 	if (!options || strncmp(options, "sb=", 3) != 0)
417 		return 1;	/* Default location */
418 	options += 3;
419 	sb_block = simple_strtoul(options, &options, 0);
420 	if (*options && *options != ',') {
421 		printk("EXT2-fs: Invalid sb specification: %s\n",
422 		       (char *) *data);
423 		return 1;
424 	}
425 	if (*options == ',')
426 		options++;
427 	*data = (void *) options;
428 	return sb_block;
429 }
430 
431 enum {
432 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
433 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
434 	Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
435 	Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
436 	Opt_acl, Opt_noacl, Opt_xip, Opt_dax, Opt_ignore, Opt_err, Opt_quota,
437 	Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
438 };
439 
440 static const match_table_t tokens = {
441 	{Opt_bsd_df, "bsddf"},
442 	{Opt_minix_df, "minixdf"},
443 	{Opt_grpid, "grpid"},
444 	{Opt_grpid, "bsdgroups"},
445 	{Opt_nogrpid, "nogrpid"},
446 	{Opt_nogrpid, "sysvgroups"},
447 	{Opt_resgid, "resgid=%u"},
448 	{Opt_resuid, "resuid=%u"},
449 	{Opt_sb, "sb=%u"},
450 	{Opt_err_cont, "errors=continue"},
451 	{Opt_err_panic, "errors=panic"},
452 	{Opt_err_ro, "errors=remount-ro"},
453 	{Opt_nouid32, "nouid32"},
454 	{Opt_nocheck, "check=none"},
455 	{Opt_nocheck, "nocheck"},
456 	{Opt_debug, "debug"},
457 	{Opt_oldalloc, "oldalloc"},
458 	{Opt_orlov, "orlov"},
459 	{Opt_nobh, "nobh"},
460 	{Opt_user_xattr, "user_xattr"},
461 	{Opt_nouser_xattr, "nouser_xattr"},
462 	{Opt_acl, "acl"},
463 	{Opt_noacl, "noacl"},
464 	{Opt_xip, "xip"},
465 	{Opt_dax, "dax"},
466 	{Opt_grpquota, "grpquota"},
467 	{Opt_ignore, "noquota"},
468 	{Opt_quota, "quota"},
469 	{Opt_usrquota, "usrquota"},
470 	{Opt_reservation, "reservation"},
471 	{Opt_noreservation, "noreservation"},
472 	{Opt_err, NULL}
473 };
474 
475 static int parse_options(char *options, struct super_block *sb,
476 			 struct ext2_mount_options *opts)
477 {
478 	char *p;
479 	substring_t args[MAX_OPT_ARGS];
480 	int option;
481 	kuid_t uid;
482 	kgid_t gid;
483 
484 	if (!options)
485 		return 1;
486 
487 	while ((p = strsep (&options, ",")) != NULL) {
488 		int token;
489 		if (!*p)
490 			continue;
491 
492 		token = match_token(p, tokens, args);
493 		switch (token) {
494 		case Opt_bsd_df:
495 			clear_opt (opts->s_mount_opt, MINIX_DF);
496 			break;
497 		case Opt_minix_df:
498 			set_opt (opts->s_mount_opt, MINIX_DF);
499 			break;
500 		case Opt_grpid:
501 			set_opt (opts->s_mount_opt, GRPID);
502 			break;
503 		case Opt_nogrpid:
504 			clear_opt (opts->s_mount_opt, GRPID);
505 			break;
506 		case Opt_resuid:
507 			if (match_int(&args[0], &option))
508 				return 0;
509 			uid = make_kuid(current_user_ns(), option);
510 			if (!uid_valid(uid)) {
511 				ext2_msg(sb, KERN_ERR, "Invalid uid value %d", option);
512 				return 0;
513 
514 			}
515 			opts->s_resuid = uid;
516 			break;
517 		case Opt_resgid:
518 			if (match_int(&args[0], &option))
519 				return 0;
520 			gid = make_kgid(current_user_ns(), option);
521 			if (!gid_valid(gid)) {
522 				ext2_msg(sb, KERN_ERR, "Invalid gid value %d", option);
523 				return 0;
524 			}
525 			opts->s_resgid = gid;
526 			break;
527 		case Opt_sb:
528 			/* handled by get_sb_block() instead of here */
529 			/* *sb_block = match_int(&args[0]); */
530 			break;
531 		case Opt_err_panic:
532 			clear_opt (opts->s_mount_opt, ERRORS_CONT);
533 			clear_opt (opts->s_mount_opt, ERRORS_RO);
534 			set_opt (opts->s_mount_opt, ERRORS_PANIC);
535 			break;
536 		case Opt_err_ro:
537 			clear_opt (opts->s_mount_opt, ERRORS_CONT);
538 			clear_opt (opts->s_mount_opt, ERRORS_PANIC);
539 			set_opt (opts->s_mount_opt, ERRORS_RO);
540 			break;
541 		case Opt_err_cont:
542 			clear_opt (opts->s_mount_opt, ERRORS_RO);
543 			clear_opt (opts->s_mount_opt, ERRORS_PANIC);
544 			set_opt (opts->s_mount_opt, ERRORS_CONT);
545 			break;
546 		case Opt_nouid32:
547 			set_opt (opts->s_mount_opt, NO_UID32);
548 			break;
549 		case Opt_nocheck:
550 			ext2_msg(sb, KERN_WARNING,
551 				"Option nocheck/check=none is deprecated and"
552 				" will be removed in June 2020.");
553 			clear_opt (opts->s_mount_opt, CHECK);
554 			break;
555 		case Opt_debug:
556 			set_opt (opts->s_mount_opt, DEBUG);
557 			break;
558 		case Opt_oldalloc:
559 			set_opt (opts->s_mount_opt, OLDALLOC);
560 			break;
561 		case Opt_orlov:
562 			clear_opt (opts->s_mount_opt, OLDALLOC);
563 			break;
564 		case Opt_nobh:
565 			set_opt (opts->s_mount_opt, NOBH);
566 			break;
567 #ifdef CONFIG_EXT2_FS_XATTR
568 		case Opt_user_xattr:
569 			set_opt (opts->s_mount_opt, XATTR_USER);
570 			break;
571 		case Opt_nouser_xattr:
572 			clear_opt (opts->s_mount_opt, XATTR_USER);
573 			break;
574 #else
575 		case Opt_user_xattr:
576 		case Opt_nouser_xattr:
577 			ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
578 				"not supported");
579 			break;
580 #endif
581 #ifdef CONFIG_EXT2_FS_POSIX_ACL
582 		case Opt_acl:
583 			set_opt(opts->s_mount_opt, POSIX_ACL);
584 			break;
585 		case Opt_noacl:
586 			clear_opt(opts->s_mount_opt, POSIX_ACL);
587 			break;
588 #else
589 		case Opt_acl:
590 		case Opt_noacl:
591 			ext2_msg(sb, KERN_INFO,
592 				"(no)acl options not supported");
593 			break;
594 #endif
595 		case Opt_xip:
596 			ext2_msg(sb, KERN_INFO, "use dax instead of xip");
597 			set_opt(opts->s_mount_opt, XIP);
598 			/* Fall through */
599 		case Opt_dax:
600 #ifdef CONFIG_FS_DAX
601 			ext2_msg(sb, KERN_WARNING,
602 		"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
603 			set_opt(opts->s_mount_opt, DAX);
604 #else
605 			ext2_msg(sb, KERN_INFO, "dax option not supported");
606 #endif
607 			break;
608 
609 #if defined(CONFIG_QUOTA)
610 		case Opt_quota:
611 		case Opt_usrquota:
612 			set_opt(opts->s_mount_opt, USRQUOTA);
613 			break;
614 
615 		case Opt_grpquota:
616 			set_opt(opts->s_mount_opt, GRPQUOTA);
617 			break;
618 #else
619 		case Opt_quota:
620 		case Opt_usrquota:
621 		case Opt_grpquota:
622 			ext2_msg(sb, KERN_INFO,
623 				"quota operations not supported");
624 			break;
625 #endif
626 
627 		case Opt_reservation:
628 			set_opt(opts->s_mount_opt, RESERVATION);
629 			ext2_msg(sb, KERN_INFO, "reservations ON");
630 			break;
631 		case Opt_noreservation:
632 			clear_opt(opts->s_mount_opt, RESERVATION);
633 			ext2_msg(sb, KERN_INFO, "reservations OFF");
634 			break;
635 		case Opt_ignore:
636 			break;
637 		default:
638 			return 0;
639 		}
640 	}
641 	return 1;
642 }
643 
644 static int ext2_setup_super (struct super_block * sb,
645 			      struct ext2_super_block * es,
646 			      int read_only)
647 {
648 	int res = 0;
649 	struct ext2_sb_info *sbi = EXT2_SB(sb);
650 
651 	if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
652 		ext2_msg(sb, KERN_ERR,
653 			"error: revision level too high, "
654 			"forcing read-only mode");
655 		res = SB_RDONLY;
656 	}
657 	if (read_only)
658 		return res;
659 	if (!(sbi->s_mount_state & EXT2_VALID_FS))
660 		ext2_msg(sb, KERN_WARNING,
661 			"warning: mounting unchecked fs, "
662 			"running e2fsck is recommended");
663 	else if ((sbi->s_mount_state & EXT2_ERROR_FS))
664 		ext2_msg(sb, KERN_WARNING,
665 			"warning: mounting fs with errors, "
666 			"running e2fsck is recommended");
667 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
668 		 le16_to_cpu(es->s_mnt_count) >=
669 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
670 		ext2_msg(sb, KERN_WARNING,
671 			"warning: maximal mount count reached, "
672 			"running e2fsck is recommended");
673 	else if (le32_to_cpu(es->s_checkinterval) &&
674 		(le32_to_cpu(es->s_lastcheck) +
675 			le32_to_cpu(es->s_checkinterval) <=
676 			ktime_get_real_seconds()))
677 		ext2_msg(sb, KERN_WARNING,
678 			"warning: checktime reached, "
679 			"running e2fsck is recommended");
680 	if (!le16_to_cpu(es->s_max_mnt_count))
681 		es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
682 	le16_add_cpu(&es->s_mnt_count, 1);
683 	if (test_opt (sb, DEBUG))
684 		ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
685 			"bpg=%lu, ipg=%lu, mo=%04lx]",
686 			EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
687 			sbi->s_frag_size,
688 			sbi->s_groups_count,
689 			EXT2_BLOCKS_PER_GROUP(sb),
690 			EXT2_INODES_PER_GROUP(sb),
691 			sbi->s_mount_opt);
692 	return res;
693 }
694 
695 static int ext2_check_descriptors(struct super_block *sb)
696 {
697 	int i;
698 	struct ext2_sb_info *sbi = EXT2_SB(sb);
699 
700 	ext2_debug ("Checking group descriptors");
701 
702 	for (i = 0; i < sbi->s_groups_count; i++) {
703 		struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
704 		ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
705 		ext2_fsblk_t last_block = ext2_group_last_block_no(sb, i);
706 
707 		if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
708 		    le32_to_cpu(gdp->bg_block_bitmap) > last_block)
709 		{
710 			ext2_error (sb, "ext2_check_descriptors",
711 				    "Block bitmap for group %d"
712 				    " not in group (block %lu)!",
713 				    i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
714 			return 0;
715 		}
716 		if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
717 		    le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
718 		{
719 			ext2_error (sb, "ext2_check_descriptors",
720 				    "Inode bitmap for group %d"
721 				    " not in group (block %lu)!",
722 				    i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
723 			return 0;
724 		}
725 		if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
726 		    le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
727 		    last_block)
728 		{
729 			ext2_error (sb, "ext2_check_descriptors",
730 				    "Inode table for group %d"
731 				    " not in group (block %lu)!",
732 				    i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
733 			return 0;
734 		}
735 	}
736 	return 1;
737 }
738 
739 /*
740  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
741  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
742  * We need to be 1 filesystem block less than the 2^32 sector limit.
743  */
744 static loff_t ext2_max_size(int bits)
745 {
746 	loff_t res = EXT2_NDIR_BLOCKS;
747 	int meta_blocks;
748 	unsigned int upper_limit;
749 	unsigned int ppb = 1 << (bits-2);
750 
751 	/* This is calculated to be the largest file size for a
752 	 * dense, file such that the total number of
753 	 * sectors in the file, including data and all indirect blocks,
754 	 * does not exceed 2^32 -1
755 	 * __u32 i_blocks representing the total number of
756 	 * 512 bytes blocks of the file
757 	 */
758 	upper_limit = (1LL << 32) - 1;
759 
760 	/* total blocks in file system block size */
761 	upper_limit >>= (bits - 9);
762 
763 	/* Compute how many blocks we can address by block tree */
764 	res += 1LL << (bits-2);
765 	res += 1LL << (2*(bits-2));
766 	res += 1LL << (3*(bits-2));
767 	/* Does block tree limit file size? */
768 	if (res < upper_limit)
769 		goto check_lfs;
770 
771 	res = upper_limit;
772 	/* How many metadata blocks are needed for addressing upper_limit? */
773 	upper_limit -= EXT2_NDIR_BLOCKS;
774 	/* indirect blocks */
775 	meta_blocks = 1;
776 	upper_limit -= ppb;
777 	/* double indirect blocks */
778 	if (upper_limit < ppb * ppb) {
779 		meta_blocks += 1 + DIV_ROUND_UP(upper_limit, ppb);
780 		res -= meta_blocks;
781 		goto check_lfs;
782 	}
783 	meta_blocks += 1 + ppb;
784 	upper_limit -= ppb * ppb;
785 	/* tripple indirect blocks for the rest */
786 	meta_blocks += 1 + DIV_ROUND_UP(upper_limit, ppb) +
787 		DIV_ROUND_UP(upper_limit, ppb*ppb);
788 	res -= meta_blocks;
789 check_lfs:
790 	res <<= bits;
791 	if (res > MAX_LFS_FILESIZE)
792 		res = MAX_LFS_FILESIZE;
793 
794 	return res;
795 }
796 
797 static unsigned long descriptor_loc(struct super_block *sb,
798 				    unsigned long logic_sb_block,
799 				    int nr)
800 {
801 	struct ext2_sb_info *sbi = EXT2_SB(sb);
802 	unsigned long bg, first_meta_bg;
803 
804 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
805 
806 	if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
807 	    nr < first_meta_bg)
808 		return (logic_sb_block + nr + 1);
809 	bg = sbi->s_desc_per_block * nr;
810 
811 	return ext2_group_first_block_no(sb, bg) + ext2_bg_has_super(sb, bg);
812 }
813 
814 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
815 {
816 	struct dax_device *dax_dev = fs_dax_get_by_bdev(sb->s_bdev);
817 	struct buffer_head * bh;
818 	struct ext2_sb_info * sbi;
819 	struct ext2_super_block * es;
820 	struct inode *root;
821 	unsigned long block;
822 	unsigned long sb_block = get_sb_block(&data);
823 	unsigned long logic_sb_block;
824 	unsigned long offset = 0;
825 	unsigned long def_mount_opts;
826 	long ret = -ENOMEM;
827 	int blocksize = BLOCK_SIZE;
828 	int db_count;
829 	int i, j;
830 	__le32 features;
831 	int err;
832 	struct ext2_mount_options opts;
833 
834 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
835 	if (!sbi)
836 		goto failed;
837 
838 	sbi->s_blockgroup_lock =
839 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
840 	if (!sbi->s_blockgroup_lock) {
841 		kfree(sbi);
842 		goto failed;
843 	}
844 	sb->s_fs_info = sbi;
845 	sbi->s_sb_block = sb_block;
846 	sbi->s_daxdev = dax_dev;
847 
848 	spin_lock_init(&sbi->s_lock);
849 	ret = -EINVAL;
850 
851 	/*
852 	 * See what the current blocksize for the device is, and
853 	 * use that as the blocksize.  Otherwise (or if the blocksize
854 	 * is smaller than the default) use the default.
855 	 * This is important for devices that have a hardware
856 	 * sectorsize that is larger than the default.
857 	 */
858 	blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
859 	if (!blocksize) {
860 		ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
861 		goto failed_sbi;
862 	}
863 
864 	/*
865 	 * If the superblock doesn't start on a hardware sector boundary,
866 	 * calculate the offset.
867 	 */
868 	if (blocksize != BLOCK_SIZE) {
869 		logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
870 		offset = (sb_block*BLOCK_SIZE) % blocksize;
871 	} else {
872 		logic_sb_block = sb_block;
873 	}
874 
875 	if (!(bh = sb_bread(sb, logic_sb_block))) {
876 		ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
877 		goto failed_sbi;
878 	}
879 	/*
880 	 * Note: s_es must be initialized as soon as possible because
881 	 *       some ext2 macro-instructions depend on its value
882 	 */
883 	es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
884 	sbi->s_es = es;
885 	sb->s_magic = le16_to_cpu(es->s_magic);
886 
887 	if (sb->s_magic != EXT2_SUPER_MAGIC)
888 		goto cantfind_ext2;
889 
890 	opts.s_mount_opt = 0;
891 	/* Set defaults before we parse the mount options */
892 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
893 	if (def_mount_opts & EXT2_DEFM_DEBUG)
894 		set_opt(opts.s_mount_opt, DEBUG);
895 	if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
896 		set_opt(opts.s_mount_opt, GRPID);
897 	if (def_mount_opts & EXT2_DEFM_UID16)
898 		set_opt(opts.s_mount_opt, NO_UID32);
899 #ifdef CONFIG_EXT2_FS_XATTR
900 	if (def_mount_opts & EXT2_DEFM_XATTR_USER)
901 		set_opt(opts.s_mount_opt, XATTR_USER);
902 #endif
903 #ifdef CONFIG_EXT2_FS_POSIX_ACL
904 	if (def_mount_opts & EXT2_DEFM_ACL)
905 		set_opt(opts.s_mount_opt, POSIX_ACL);
906 #endif
907 
908 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
909 		set_opt(opts.s_mount_opt, ERRORS_PANIC);
910 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
911 		set_opt(opts.s_mount_opt, ERRORS_CONT);
912 	else
913 		set_opt(opts.s_mount_opt, ERRORS_RO);
914 
915 	opts.s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
916 	opts.s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
917 
918 	set_opt(opts.s_mount_opt, RESERVATION);
919 
920 	if (!parse_options((char *) data, sb, &opts))
921 		goto failed_mount;
922 
923 	sbi->s_mount_opt = opts.s_mount_opt;
924 	sbi->s_resuid = opts.s_resuid;
925 	sbi->s_resgid = opts.s_resgid;
926 
927 	sb->s_flags = (sb->s_flags & ~SB_POSIXACL) |
928 		(test_opt(sb, POSIX_ACL) ? SB_POSIXACL : 0);
929 	sb->s_iflags |= SB_I_CGROUPWB;
930 
931 	if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
932 	    (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
933 	     EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
934 	     EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
935 		ext2_msg(sb, KERN_WARNING,
936 			"warning: feature flags set on rev 0 fs, "
937 			"running e2fsck is recommended");
938 	/*
939 	 * Check feature flags regardless of the revision level, since we
940 	 * previously didn't change the revision level when setting the flags,
941 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
942 	 */
943 	features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
944 	if (features) {
945 		ext2_msg(sb, KERN_ERR,	"error: couldn't mount because of "
946 		       "unsupported optional features (%x)",
947 			le32_to_cpu(features));
948 		goto failed_mount;
949 	}
950 	if (!sb_rdonly(sb) && (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
951 		ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
952 		       "unsupported optional features (%x)",
953 		       le32_to_cpu(features));
954 		goto failed_mount;
955 	}
956 
957 	blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
958 
959 	if (test_opt(sb, DAX)) {
960 		if (!bdev_dax_supported(sb->s_bdev, blocksize)) {
961 			ext2_msg(sb, KERN_ERR,
962 				"DAX unsupported by block device. Turning off DAX.");
963 			clear_opt(sbi->s_mount_opt, DAX);
964 		}
965 	}
966 
967 	/* If the blocksize doesn't match, re-read the thing.. */
968 	if (sb->s_blocksize != blocksize) {
969 		brelse(bh);
970 
971 		if (!sb_set_blocksize(sb, blocksize)) {
972 			ext2_msg(sb, KERN_ERR,
973 				"error: bad blocksize %d", blocksize);
974 			goto failed_sbi;
975 		}
976 
977 		logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
978 		offset = (sb_block*BLOCK_SIZE) % blocksize;
979 		bh = sb_bread(sb, logic_sb_block);
980 		if(!bh) {
981 			ext2_msg(sb, KERN_ERR, "error: couldn't read"
982 				"superblock on 2nd try");
983 			goto failed_sbi;
984 		}
985 		es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
986 		sbi->s_es = es;
987 		if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
988 			ext2_msg(sb, KERN_ERR, "error: magic mismatch");
989 			goto failed_mount;
990 		}
991 	}
992 
993 	sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
994 	sb->s_max_links = EXT2_LINK_MAX;
995 	sb->s_time_min = S32_MIN;
996 	sb->s_time_max = S32_MAX;
997 
998 	if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
999 		sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
1000 		sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
1001 	} else {
1002 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
1003 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
1004 		if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
1005 		    !is_power_of_2(sbi->s_inode_size) ||
1006 		    (sbi->s_inode_size > blocksize)) {
1007 			ext2_msg(sb, KERN_ERR,
1008 				"error: unsupported inode size: %d",
1009 				sbi->s_inode_size);
1010 			goto failed_mount;
1011 		}
1012 	}
1013 
1014 	sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
1015 				   le32_to_cpu(es->s_log_frag_size);
1016 	if (sbi->s_frag_size == 0)
1017 		goto cantfind_ext2;
1018 	sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
1019 
1020 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
1021 	sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
1022 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
1023 
1024 	sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
1025 	if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
1026 		goto cantfind_ext2;
1027 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
1028 					sbi->s_inodes_per_block;
1029 	sbi->s_desc_per_block = sb->s_blocksize /
1030 					sizeof (struct ext2_group_desc);
1031 	sbi->s_sbh = bh;
1032 	sbi->s_mount_state = le16_to_cpu(es->s_state);
1033 	sbi->s_addr_per_block_bits =
1034 		ilog2 (EXT2_ADDR_PER_BLOCK(sb));
1035 	sbi->s_desc_per_block_bits =
1036 		ilog2 (EXT2_DESC_PER_BLOCK(sb));
1037 
1038 	if (sb->s_magic != EXT2_SUPER_MAGIC)
1039 		goto cantfind_ext2;
1040 
1041 	if (sb->s_blocksize != bh->b_size) {
1042 		if (!silent)
1043 			ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
1044 		goto failed_mount;
1045 	}
1046 
1047 	if (sb->s_blocksize != sbi->s_frag_size) {
1048 		ext2_msg(sb, KERN_ERR,
1049 			"error: fragsize %lu != blocksize %lu"
1050 			"(not supported yet)",
1051 			sbi->s_frag_size, sb->s_blocksize);
1052 		goto failed_mount;
1053 	}
1054 
1055 	if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
1056 		ext2_msg(sb, KERN_ERR,
1057 			"error: #blocks per group too big: %lu",
1058 			sbi->s_blocks_per_group);
1059 		goto failed_mount;
1060 	}
1061 	if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
1062 		ext2_msg(sb, KERN_ERR,
1063 			"error: #fragments per group too big: %lu",
1064 			sbi->s_frags_per_group);
1065 		goto failed_mount;
1066 	}
1067 	if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
1068 		ext2_msg(sb, KERN_ERR,
1069 			"error: #inodes per group too big: %lu",
1070 			sbi->s_inodes_per_group);
1071 		goto failed_mount;
1072 	}
1073 
1074 	if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
1075 		goto cantfind_ext2;
1076  	sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
1077  				le32_to_cpu(es->s_first_data_block) - 1)
1078  					/ EXT2_BLOCKS_PER_GROUP(sb)) + 1;
1079 	db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
1080 		   EXT2_DESC_PER_BLOCK(sb);
1081 	sbi->s_group_desc = kmalloc_array (db_count,
1082 					   sizeof(struct buffer_head *),
1083 					   GFP_KERNEL);
1084 	if (sbi->s_group_desc == NULL) {
1085 		ret = -ENOMEM;
1086 		ext2_msg(sb, KERN_ERR, "error: not enough memory");
1087 		goto failed_mount;
1088 	}
1089 	bgl_lock_init(sbi->s_blockgroup_lock);
1090 	sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1091 	if (!sbi->s_debts) {
1092 		ret = -ENOMEM;
1093 		ext2_msg(sb, KERN_ERR, "error: not enough memory");
1094 		goto failed_mount_group_desc;
1095 	}
1096 	for (i = 0; i < db_count; i++) {
1097 		block = descriptor_loc(sb, logic_sb_block, i);
1098 		sbi->s_group_desc[i] = sb_bread(sb, block);
1099 		if (!sbi->s_group_desc[i]) {
1100 			for (j = 0; j < i; j++)
1101 				brelse (sbi->s_group_desc[j]);
1102 			ext2_msg(sb, KERN_ERR,
1103 				"error: unable to read group descriptors");
1104 			goto failed_mount_group_desc;
1105 		}
1106 	}
1107 	if (!ext2_check_descriptors (sb)) {
1108 		ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1109 		goto failed_mount2;
1110 	}
1111 	sbi->s_gdb_count = db_count;
1112 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1113 	spin_lock_init(&sbi->s_next_gen_lock);
1114 
1115 	/* per fileystem reservation list head & lock */
1116 	spin_lock_init(&sbi->s_rsv_window_lock);
1117 	sbi->s_rsv_window_root = RB_ROOT;
1118 	/*
1119 	 * Add a single, static dummy reservation to the start of the
1120 	 * reservation window list --- it gives us a placeholder for
1121 	 * append-at-start-of-list which makes the allocation logic
1122 	 * _much_ simpler.
1123 	 */
1124 	sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1125 	sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1126 	sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1127 	sbi->s_rsv_window_head.rsv_goal_size = 0;
1128 	ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1129 
1130 	err = percpu_counter_init(&sbi->s_freeblocks_counter,
1131 				ext2_count_free_blocks(sb), GFP_KERNEL);
1132 	if (!err) {
1133 		err = percpu_counter_init(&sbi->s_freeinodes_counter,
1134 				ext2_count_free_inodes(sb), GFP_KERNEL);
1135 	}
1136 	if (!err) {
1137 		err = percpu_counter_init(&sbi->s_dirs_counter,
1138 				ext2_count_dirs(sb), GFP_KERNEL);
1139 	}
1140 	if (err) {
1141 		ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1142 		goto failed_mount3;
1143 	}
1144 
1145 #ifdef CONFIG_EXT2_FS_XATTR
1146 	sbi->s_ea_block_cache = ext2_xattr_create_cache();
1147 	if (!sbi->s_ea_block_cache) {
1148 		ret = -ENOMEM;
1149 		ext2_msg(sb, KERN_ERR, "Failed to create ea_block_cache");
1150 		goto failed_mount3;
1151 	}
1152 #endif
1153 	/*
1154 	 * set up enough so that it can read an inode
1155 	 */
1156 	sb->s_op = &ext2_sops;
1157 	sb->s_export_op = &ext2_export_ops;
1158 	sb->s_xattr = ext2_xattr_handlers;
1159 
1160 #ifdef CONFIG_QUOTA
1161 	sb->dq_op = &dquot_operations;
1162 	sb->s_qcop = &ext2_quotactl_ops;
1163 	sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP;
1164 #endif
1165 
1166 	root = ext2_iget(sb, EXT2_ROOT_INO);
1167 	if (IS_ERR(root)) {
1168 		ret = PTR_ERR(root);
1169 		goto failed_mount3;
1170 	}
1171 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1172 		iput(root);
1173 		ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1174 		goto failed_mount3;
1175 	}
1176 
1177 	sb->s_root = d_make_root(root);
1178 	if (!sb->s_root) {
1179 		ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1180 		ret = -ENOMEM;
1181 		goto failed_mount3;
1182 	}
1183 	if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1184 		ext2_msg(sb, KERN_WARNING,
1185 			"warning: mounting ext3 filesystem as ext2");
1186 	if (ext2_setup_super (sb, es, sb_rdonly(sb)))
1187 		sb->s_flags |= SB_RDONLY;
1188 	ext2_write_super(sb);
1189 	return 0;
1190 
1191 cantfind_ext2:
1192 	if (!silent)
1193 		ext2_msg(sb, KERN_ERR,
1194 			"error: can't find an ext2 filesystem on dev %s.",
1195 			sb->s_id);
1196 	goto failed_mount;
1197 failed_mount3:
1198 	ext2_xattr_destroy_cache(sbi->s_ea_block_cache);
1199 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
1200 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
1201 	percpu_counter_destroy(&sbi->s_dirs_counter);
1202 failed_mount2:
1203 	for (i = 0; i < db_count; i++)
1204 		brelse(sbi->s_group_desc[i]);
1205 failed_mount_group_desc:
1206 	kfree(sbi->s_group_desc);
1207 	kfree(sbi->s_debts);
1208 failed_mount:
1209 	brelse(bh);
1210 failed_sbi:
1211 	sb->s_fs_info = NULL;
1212 	kfree(sbi->s_blockgroup_lock);
1213 	kfree(sbi);
1214 failed:
1215 	fs_put_dax(dax_dev);
1216 	return ret;
1217 }
1218 
1219 static void ext2_clear_super_error(struct super_block *sb)
1220 {
1221 	struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1222 
1223 	if (buffer_write_io_error(sbh)) {
1224 		/*
1225 		 * Oh, dear.  A previous attempt to write the
1226 		 * superblock failed.  This could happen because the
1227 		 * USB device was yanked out.  Or it could happen to
1228 		 * be a transient write error and maybe the block will
1229 		 * be remapped.  Nothing we can do but to retry the
1230 		 * write and hope for the best.
1231 		 */
1232 		ext2_msg(sb, KERN_ERR,
1233 		       "previous I/O error to superblock detected");
1234 		clear_buffer_write_io_error(sbh);
1235 		set_buffer_uptodate(sbh);
1236 	}
1237 }
1238 
1239 void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1240 		     int wait)
1241 {
1242 	ext2_clear_super_error(sb);
1243 	spin_lock(&EXT2_SB(sb)->s_lock);
1244 	es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1245 	es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1246 	es->s_wtime = cpu_to_le32(ktime_get_real_seconds());
1247 	/* unlock before we do IO */
1248 	spin_unlock(&EXT2_SB(sb)->s_lock);
1249 	mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1250 	if (wait)
1251 		sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1252 }
1253 
1254 /*
1255  * In the second extended file system, it is not necessary to
1256  * write the super block since we use a mapping of the
1257  * disk super block in a buffer.
1258  *
1259  * However, this function is still used to set the fs valid
1260  * flags to 0.  We need to set this flag to 0 since the fs
1261  * may have been checked while mounted and e2fsck may have
1262  * set s_state to EXT2_VALID_FS after some corrections.
1263  */
1264 static int ext2_sync_fs(struct super_block *sb, int wait)
1265 {
1266 	struct ext2_sb_info *sbi = EXT2_SB(sb);
1267 	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1268 
1269 	/*
1270 	 * Write quota structures to quota file, sync_blockdev() will write
1271 	 * them to disk later
1272 	 */
1273 	dquot_writeback_dquots(sb, -1);
1274 
1275 	spin_lock(&sbi->s_lock);
1276 	if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1277 		ext2_debug("setting valid to 0\n");
1278 		es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1279 	}
1280 	spin_unlock(&sbi->s_lock);
1281 	ext2_sync_super(sb, es, wait);
1282 	return 0;
1283 }
1284 
1285 static int ext2_freeze(struct super_block *sb)
1286 {
1287 	struct ext2_sb_info *sbi = EXT2_SB(sb);
1288 
1289 	/*
1290 	 * Open but unlinked files present? Keep EXT2_VALID_FS flag cleared
1291 	 * because we have unattached inodes and thus filesystem is not fully
1292 	 * consistent.
1293 	 */
1294 	if (atomic_long_read(&sb->s_remove_count)) {
1295 		ext2_sync_fs(sb, 1);
1296 		return 0;
1297 	}
1298 	/* Set EXT2_FS_VALID flag */
1299 	spin_lock(&sbi->s_lock);
1300 	sbi->s_es->s_state = cpu_to_le16(sbi->s_mount_state);
1301 	spin_unlock(&sbi->s_lock);
1302 	ext2_sync_super(sb, sbi->s_es, 1);
1303 
1304 	return 0;
1305 }
1306 
1307 static int ext2_unfreeze(struct super_block *sb)
1308 {
1309 	/* Just write sb to clear EXT2_VALID_FS flag */
1310 	ext2_write_super(sb);
1311 
1312 	return 0;
1313 }
1314 
1315 static void ext2_write_super(struct super_block *sb)
1316 {
1317 	if (!sb_rdonly(sb))
1318 		ext2_sync_fs(sb, 1);
1319 }
1320 
1321 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1322 {
1323 	struct ext2_sb_info * sbi = EXT2_SB(sb);
1324 	struct ext2_super_block * es;
1325 	struct ext2_mount_options new_opts;
1326 	int err;
1327 
1328 	sync_filesystem(sb);
1329 
1330 	spin_lock(&sbi->s_lock);
1331 	new_opts.s_mount_opt = sbi->s_mount_opt;
1332 	new_opts.s_resuid = sbi->s_resuid;
1333 	new_opts.s_resgid = sbi->s_resgid;
1334 	spin_unlock(&sbi->s_lock);
1335 
1336 	if (!parse_options(data, sb, &new_opts))
1337 		return -EINVAL;
1338 
1339 	spin_lock(&sbi->s_lock);
1340 	es = sbi->s_es;
1341 	if ((sbi->s_mount_opt ^ new_opts.s_mount_opt) & EXT2_MOUNT_DAX) {
1342 		ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1343 			 "dax flag with busy inodes while remounting");
1344 		new_opts.s_mount_opt ^= EXT2_MOUNT_DAX;
1345 	}
1346 	if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1347 		goto out_set;
1348 	if (*flags & SB_RDONLY) {
1349 		if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1350 		    !(sbi->s_mount_state & EXT2_VALID_FS))
1351 			goto out_set;
1352 
1353 		/*
1354 		 * OK, we are remounting a valid rw partition rdonly, so set
1355 		 * the rdonly flag and then mark the partition as valid again.
1356 		 */
1357 		es->s_state = cpu_to_le16(sbi->s_mount_state);
1358 		es->s_mtime = cpu_to_le32(ktime_get_real_seconds());
1359 		spin_unlock(&sbi->s_lock);
1360 
1361 		err = dquot_suspend(sb, -1);
1362 		if (err < 0)
1363 			return err;
1364 
1365 		ext2_sync_super(sb, es, 1);
1366 	} else {
1367 		__le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1368 					       ~EXT2_FEATURE_RO_COMPAT_SUPP);
1369 		if (ret) {
1370 			spin_unlock(&sbi->s_lock);
1371 			ext2_msg(sb, KERN_WARNING,
1372 				"warning: couldn't remount RDWR because of "
1373 				"unsupported optional features (%x).",
1374 				le32_to_cpu(ret));
1375 			return -EROFS;
1376 		}
1377 		/*
1378 		 * Mounting a RDONLY partition read-write, so reread and
1379 		 * store the current valid flag.  (It may have been changed
1380 		 * by e2fsck since we originally mounted the partition.)
1381 		 */
1382 		sbi->s_mount_state = le16_to_cpu(es->s_state);
1383 		if (!ext2_setup_super (sb, es, 0))
1384 			sb->s_flags &= ~SB_RDONLY;
1385 		spin_unlock(&sbi->s_lock);
1386 
1387 		ext2_write_super(sb);
1388 
1389 		dquot_resume(sb, -1);
1390 	}
1391 
1392 	spin_lock(&sbi->s_lock);
1393 out_set:
1394 	sbi->s_mount_opt = new_opts.s_mount_opt;
1395 	sbi->s_resuid = new_opts.s_resuid;
1396 	sbi->s_resgid = new_opts.s_resgid;
1397 	sb->s_flags = (sb->s_flags & ~SB_POSIXACL) |
1398 		(test_opt(sb, POSIX_ACL) ? SB_POSIXACL : 0);
1399 	spin_unlock(&sbi->s_lock);
1400 
1401 	return 0;
1402 }
1403 
1404 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1405 {
1406 	struct super_block *sb = dentry->d_sb;
1407 	struct ext2_sb_info *sbi = EXT2_SB(sb);
1408 	struct ext2_super_block *es = sbi->s_es;
1409 	u64 fsid;
1410 
1411 	spin_lock(&sbi->s_lock);
1412 
1413 	if (test_opt (sb, MINIX_DF))
1414 		sbi->s_overhead_last = 0;
1415 	else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1416 		unsigned long i, overhead = 0;
1417 		smp_rmb();
1418 
1419 		/*
1420 		 * Compute the overhead (FS structures). This is constant
1421 		 * for a given filesystem unless the number of block groups
1422 		 * changes so we cache the previous value until it does.
1423 		 */
1424 
1425 		/*
1426 		 * All of the blocks before first_data_block are
1427 		 * overhead
1428 		 */
1429 		overhead = le32_to_cpu(es->s_first_data_block);
1430 
1431 		/*
1432 		 * Add the overhead attributed to the superblock and
1433 		 * block group descriptors.  If the sparse superblocks
1434 		 * feature is turned on, then not all groups have this.
1435 		 */
1436 		for (i = 0; i < sbi->s_groups_count; i++)
1437 			overhead += ext2_bg_has_super(sb, i) +
1438 				ext2_bg_num_gdb(sb, i);
1439 
1440 		/*
1441 		 * Every block group has an inode bitmap, a block
1442 		 * bitmap, and an inode table.
1443 		 */
1444 		overhead += (sbi->s_groups_count *
1445 			     (2 + sbi->s_itb_per_group));
1446 		sbi->s_overhead_last = overhead;
1447 		smp_wmb();
1448 		sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1449 	}
1450 
1451 	buf->f_type = EXT2_SUPER_MAGIC;
1452 	buf->f_bsize = sb->s_blocksize;
1453 	buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1454 	buf->f_bfree = ext2_count_free_blocks(sb);
1455 	es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1456 	buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1457 	if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1458 		buf->f_bavail = 0;
1459 	buf->f_files = le32_to_cpu(es->s_inodes_count);
1460 	buf->f_ffree = ext2_count_free_inodes(sb);
1461 	es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1462 	buf->f_namelen = EXT2_NAME_LEN;
1463 	fsid = le64_to_cpup((void *)es->s_uuid) ^
1464 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1465 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1466 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1467 	spin_unlock(&sbi->s_lock);
1468 	return 0;
1469 }
1470 
1471 static struct dentry *ext2_mount(struct file_system_type *fs_type,
1472 	int flags, const char *dev_name, void *data)
1473 {
1474 	return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1475 }
1476 
1477 #ifdef CONFIG_QUOTA
1478 
1479 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1480  * acquiring the locks... As quota files are never truncated and quota code
1481  * itself serializes the operations (and no one else should touch the files)
1482  * we don't have to be afraid of races */
1483 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1484 			       size_t len, loff_t off)
1485 {
1486 	struct inode *inode = sb_dqopt(sb)->files[type];
1487 	sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1488 	int err = 0;
1489 	int offset = off & (sb->s_blocksize - 1);
1490 	int tocopy;
1491 	size_t toread;
1492 	struct buffer_head tmp_bh;
1493 	struct buffer_head *bh;
1494 	loff_t i_size = i_size_read(inode);
1495 
1496 	if (off > i_size)
1497 		return 0;
1498 	if (off+len > i_size)
1499 		len = i_size-off;
1500 	toread = len;
1501 	while (toread > 0) {
1502 		tocopy = sb->s_blocksize - offset < toread ?
1503 				sb->s_blocksize - offset : toread;
1504 
1505 		tmp_bh.b_state = 0;
1506 		tmp_bh.b_size = sb->s_blocksize;
1507 		err = ext2_get_block(inode, blk, &tmp_bh, 0);
1508 		if (err < 0)
1509 			return err;
1510 		if (!buffer_mapped(&tmp_bh))	/* A hole? */
1511 			memset(data, 0, tocopy);
1512 		else {
1513 			bh = sb_bread(sb, tmp_bh.b_blocknr);
1514 			if (!bh)
1515 				return -EIO;
1516 			memcpy(data, bh->b_data+offset, tocopy);
1517 			brelse(bh);
1518 		}
1519 		offset = 0;
1520 		toread -= tocopy;
1521 		data += tocopy;
1522 		blk++;
1523 	}
1524 	return len;
1525 }
1526 
1527 /* Write to quotafile */
1528 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1529 				const char *data, size_t len, loff_t off)
1530 {
1531 	struct inode *inode = sb_dqopt(sb)->files[type];
1532 	sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1533 	int err = 0;
1534 	int offset = off & (sb->s_blocksize - 1);
1535 	int tocopy;
1536 	size_t towrite = len;
1537 	struct buffer_head tmp_bh;
1538 	struct buffer_head *bh;
1539 
1540 	while (towrite > 0) {
1541 		tocopy = sb->s_blocksize - offset < towrite ?
1542 				sb->s_blocksize - offset : towrite;
1543 
1544 		tmp_bh.b_state = 0;
1545 		tmp_bh.b_size = sb->s_blocksize;
1546 		err = ext2_get_block(inode, blk, &tmp_bh, 1);
1547 		if (err < 0)
1548 			goto out;
1549 		if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1550 			bh = sb_bread(sb, tmp_bh.b_blocknr);
1551 		else
1552 			bh = sb_getblk(sb, tmp_bh.b_blocknr);
1553 		if (unlikely(!bh)) {
1554 			err = -EIO;
1555 			goto out;
1556 		}
1557 		lock_buffer(bh);
1558 		memcpy(bh->b_data+offset, data, tocopy);
1559 		flush_dcache_page(bh->b_page);
1560 		set_buffer_uptodate(bh);
1561 		mark_buffer_dirty(bh);
1562 		unlock_buffer(bh);
1563 		brelse(bh);
1564 		offset = 0;
1565 		towrite -= tocopy;
1566 		data += tocopy;
1567 		blk++;
1568 	}
1569 out:
1570 	if (len == towrite)
1571 		return err;
1572 	if (inode->i_size < off+len-towrite)
1573 		i_size_write(inode, off+len-towrite);
1574 	inode_inc_iversion(inode);
1575 	inode->i_mtime = inode->i_ctime = current_time(inode);
1576 	mark_inode_dirty(inode);
1577 	return len - towrite;
1578 }
1579 
1580 static int ext2_quota_on(struct super_block *sb, int type, int format_id,
1581 			 const struct path *path)
1582 {
1583 	int err;
1584 	struct inode *inode;
1585 
1586 	err = dquot_quota_on(sb, type, format_id, path);
1587 	if (err)
1588 		return err;
1589 
1590 	inode = d_inode(path->dentry);
1591 	inode_lock(inode);
1592 	EXT2_I(inode)->i_flags |= EXT2_NOATIME_FL | EXT2_IMMUTABLE_FL;
1593 	inode_set_flags(inode, S_NOATIME | S_IMMUTABLE,
1594 			S_NOATIME | S_IMMUTABLE);
1595 	inode_unlock(inode);
1596 	mark_inode_dirty(inode);
1597 
1598 	return 0;
1599 }
1600 
1601 static int ext2_quota_off(struct super_block *sb, int type)
1602 {
1603 	struct inode *inode = sb_dqopt(sb)->files[type];
1604 	int err;
1605 
1606 	if (!inode || !igrab(inode))
1607 		goto out;
1608 
1609 	err = dquot_quota_off(sb, type);
1610 	if (err)
1611 		goto out_put;
1612 
1613 	inode_lock(inode);
1614 	EXT2_I(inode)->i_flags &= ~(EXT2_NOATIME_FL | EXT2_IMMUTABLE_FL);
1615 	inode_set_flags(inode, 0, S_NOATIME | S_IMMUTABLE);
1616 	inode_unlock(inode);
1617 	mark_inode_dirty(inode);
1618 out_put:
1619 	iput(inode);
1620 	return err;
1621 out:
1622 	return dquot_quota_off(sb, type);
1623 }
1624 
1625 #endif
1626 
1627 static struct file_system_type ext2_fs_type = {
1628 	.owner		= THIS_MODULE,
1629 	.name		= "ext2",
1630 	.mount		= ext2_mount,
1631 	.kill_sb	= kill_block_super,
1632 	.fs_flags	= FS_REQUIRES_DEV,
1633 };
1634 MODULE_ALIAS_FS("ext2");
1635 
1636 static int __init init_ext2_fs(void)
1637 {
1638 	int err;
1639 
1640 	err = init_inodecache();
1641 	if (err)
1642 		return err;
1643         err = register_filesystem(&ext2_fs_type);
1644 	if (err)
1645 		goto out;
1646 	return 0;
1647 out:
1648 	destroy_inodecache();
1649 	return err;
1650 }
1651 
1652 static void __exit exit_ext2_fs(void)
1653 {
1654 	unregister_filesystem(&ext2_fs_type);
1655 	destroy_inodecache();
1656 }
1657 
1658 MODULE_AUTHOR("Remy Card and others");
1659 MODULE_DESCRIPTION("Second Extended Filesystem");
1660 MODULE_LICENSE("GPL");
1661 module_init(init_ext2_fs)
1662 module_exit(exit_ext2_fs)
1663