xref: /openbmc/linux/fs/ext2/super.c (revision fe0a5788)
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_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_debug, "debug"},
455 	{Opt_oldalloc, "oldalloc"},
456 	{Opt_orlov, "orlov"},
457 	{Opt_nobh, "nobh"},
458 	{Opt_user_xattr, "user_xattr"},
459 	{Opt_nouser_xattr, "nouser_xattr"},
460 	{Opt_acl, "acl"},
461 	{Opt_noacl, "noacl"},
462 	{Opt_xip, "xip"},
463 	{Opt_dax, "dax"},
464 	{Opt_grpquota, "grpquota"},
465 	{Opt_ignore, "noquota"},
466 	{Opt_quota, "quota"},
467 	{Opt_usrquota, "usrquota"},
468 	{Opt_reservation, "reservation"},
469 	{Opt_noreservation, "noreservation"},
470 	{Opt_err, NULL}
471 };
472 
473 static int parse_options(char *options, struct super_block *sb,
474 			 struct ext2_mount_options *opts)
475 {
476 	char *p;
477 	substring_t args[MAX_OPT_ARGS];
478 	int option;
479 	kuid_t uid;
480 	kgid_t gid;
481 
482 	if (!options)
483 		return 1;
484 
485 	while ((p = strsep (&options, ",")) != NULL) {
486 		int token;
487 		if (!*p)
488 			continue;
489 
490 		token = match_token(p, tokens, args);
491 		switch (token) {
492 		case Opt_bsd_df:
493 			clear_opt (opts->s_mount_opt, MINIX_DF);
494 			break;
495 		case Opt_minix_df:
496 			set_opt (opts->s_mount_opt, MINIX_DF);
497 			break;
498 		case Opt_grpid:
499 			set_opt (opts->s_mount_opt, GRPID);
500 			break;
501 		case Opt_nogrpid:
502 			clear_opt (opts->s_mount_opt, GRPID);
503 			break;
504 		case Opt_resuid:
505 			if (match_int(&args[0], &option))
506 				return 0;
507 			uid = make_kuid(current_user_ns(), option);
508 			if (!uid_valid(uid)) {
509 				ext2_msg(sb, KERN_ERR, "Invalid uid value %d", option);
510 				return 0;
511 
512 			}
513 			opts->s_resuid = uid;
514 			break;
515 		case Opt_resgid:
516 			if (match_int(&args[0], &option))
517 				return 0;
518 			gid = make_kgid(current_user_ns(), option);
519 			if (!gid_valid(gid)) {
520 				ext2_msg(sb, KERN_ERR, "Invalid gid value %d", option);
521 				return 0;
522 			}
523 			opts->s_resgid = gid;
524 			break;
525 		case Opt_sb:
526 			/* handled by get_sb_block() instead of here */
527 			/* *sb_block = match_int(&args[0]); */
528 			break;
529 		case Opt_err_panic:
530 			clear_opt (opts->s_mount_opt, ERRORS_CONT);
531 			clear_opt (opts->s_mount_opt, ERRORS_RO);
532 			set_opt (opts->s_mount_opt, ERRORS_PANIC);
533 			break;
534 		case Opt_err_ro:
535 			clear_opt (opts->s_mount_opt, ERRORS_CONT);
536 			clear_opt (opts->s_mount_opt, ERRORS_PANIC);
537 			set_opt (opts->s_mount_opt, ERRORS_RO);
538 			break;
539 		case Opt_err_cont:
540 			clear_opt (opts->s_mount_opt, ERRORS_RO);
541 			clear_opt (opts->s_mount_opt, ERRORS_PANIC);
542 			set_opt (opts->s_mount_opt, ERRORS_CONT);
543 			break;
544 		case Opt_nouid32:
545 			set_opt (opts->s_mount_opt, NO_UID32);
546 			break;
547 		case Opt_debug:
548 			set_opt (opts->s_mount_opt, DEBUG);
549 			break;
550 		case Opt_oldalloc:
551 			set_opt (opts->s_mount_opt, OLDALLOC);
552 			break;
553 		case Opt_orlov:
554 			clear_opt (opts->s_mount_opt, OLDALLOC);
555 			break;
556 		case Opt_nobh:
557 			set_opt (opts->s_mount_opt, NOBH);
558 			break;
559 #ifdef CONFIG_EXT2_FS_XATTR
560 		case Opt_user_xattr:
561 			set_opt (opts->s_mount_opt, XATTR_USER);
562 			break;
563 		case Opt_nouser_xattr:
564 			clear_opt (opts->s_mount_opt, XATTR_USER);
565 			break;
566 #else
567 		case Opt_user_xattr:
568 		case Opt_nouser_xattr:
569 			ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
570 				"not supported");
571 			break;
572 #endif
573 #ifdef CONFIG_EXT2_FS_POSIX_ACL
574 		case Opt_acl:
575 			set_opt(opts->s_mount_opt, POSIX_ACL);
576 			break;
577 		case Opt_noacl:
578 			clear_opt(opts->s_mount_opt, POSIX_ACL);
579 			break;
580 #else
581 		case Opt_acl:
582 		case Opt_noacl:
583 			ext2_msg(sb, KERN_INFO,
584 				"(no)acl options not supported");
585 			break;
586 #endif
587 		case Opt_xip:
588 			ext2_msg(sb, KERN_INFO, "use dax instead of xip");
589 			set_opt(opts->s_mount_opt, XIP);
590 			fallthrough;
591 		case Opt_dax:
592 #ifdef CONFIG_FS_DAX
593 			ext2_msg(sb, KERN_WARNING,
594 		"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
595 			set_opt(opts->s_mount_opt, DAX);
596 #else
597 			ext2_msg(sb, KERN_INFO, "dax option not supported");
598 #endif
599 			break;
600 
601 #if defined(CONFIG_QUOTA)
602 		case Opt_quota:
603 		case Opt_usrquota:
604 			set_opt(opts->s_mount_opt, USRQUOTA);
605 			break;
606 
607 		case Opt_grpquota:
608 			set_opt(opts->s_mount_opt, GRPQUOTA);
609 			break;
610 #else
611 		case Opt_quota:
612 		case Opt_usrquota:
613 		case Opt_grpquota:
614 			ext2_msg(sb, KERN_INFO,
615 				"quota operations not supported");
616 			break;
617 #endif
618 
619 		case Opt_reservation:
620 			set_opt(opts->s_mount_opt, RESERVATION);
621 			ext2_msg(sb, KERN_INFO, "reservations ON");
622 			break;
623 		case Opt_noreservation:
624 			clear_opt(opts->s_mount_opt, RESERVATION);
625 			ext2_msg(sb, KERN_INFO, "reservations OFF");
626 			break;
627 		case Opt_ignore:
628 			break;
629 		default:
630 			return 0;
631 		}
632 	}
633 	return 1;
634 }
635 
636 static int ext2_setup_super (struct super_block * sb,
637 			      struct ext2_super_block * es,
638 			      int read_only)
639 {
640 	int res = 0;
641 	struct ext2_sb_info *sbi = EXT2_SB(sb);
642 
643 	if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
644 		ext2_msg(sb, KERN_ERR,
645 			"error: revision level too high, "
646 			"forcing read-only mode");
647 		res = SB_RDONLY;
648 	}
649 	if (read_only)
650 		return res;
651 	if (!(sbi->s_mount_state & EXT2_VALID_FS))
652 		ext2_msg(sb, KERN_WARNING,
653 			"warning: mounting unchecked fs, "
654 			"running e2fsck is recommended");
655 	else if ((sbi->s_mount_state & EXT2_ERROR_FS))
656 		ext2_msg(sb, KERN_WARNING,
657 			"warning: mounting fs with errors, "
658 			"running e2fsck is recommended");
659 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
660 		 le16_to_cpu(es->s_mnt_count) >=
661 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
662 		ext2_msg(sb, KERN_WARNING,
663 			"warning: maximal mount count reached, "
664 			"running e2fsck is recommended");
665 	else if (le32_to_cpu(es->s_checkinterval) &&
666 		(le32_to_cpu(es->s_lastcheck) +
667 			le32_to_cpu(es->s_checkinterval) <=
668 			ktime_get_real_seconds()))
669 		ext2_msg(sb, KERN_WARNING,
670 			"warning: checktime reached, "
671 			"running e2fsck is recommended");
672 	if (!le16_to_cpu(es->s_max_mnt_count))
673 		es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
674 	le16_add_cpu(&es->s_mnt_count, 1);
675 	if (test_opt (sb, DEBUG))
676 		ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
677 			"bpg=%lu, ipg=%lu, mo=%04lx]",
678 			EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
679 			sbi->s_frag_size,
680 			sbi->s_groups_count,
681 			EXT2_BLOCKS_PER_GROUP(sb),
682 			EXT2_INODES_PER_GROUP(sb),
683 			sbi->s_mount_opt);
684 	return res;
685 }
686 
687 static int ext2_check_descriptors(struct super_block *sb)
688 {
689 	int i;
690 	struct ext2_sb_info *sbi = EXT2_SB(sb);
691 
692 	ext2_debug ("Checking group descriptors");
693 
694 	for (i = 0; i < sbi->s_groups_count; i++) {
695 		struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
696 		ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
697 		ext2_fsblk_t last_block = ext2_group_last_block_no(sb, i);
698 
699 		if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
700 		    le32_to_cpu(gdp->bg_block_bitmap) > last_block)
701 		{
702 			ext2_error (sb, "ext2_check_descriptors",
703 				    "Block bitmap for group %d"
704 				    " not in group (block %lu)!",
705 				    i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
706 			return 0;
707 		}
708 		if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
709 		    le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
710 		{
711 			ext2_error (sb, "ext2_check_descriptors",
712 				    "Inode bitmap for group %d"
713 				    " not in group (block %lu)!",
714 				    i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
715 			return 0;
716 		}
717 		if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
718 		    le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
719 		    last_block)
720 		{
721 			ext2_error (sb, "ext2_check_descriptors",
722 				    "Inode table for group %d"
723 				    " not in group (block %lu)!",
724 				    i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
725 			return 0;
726 		}
727 	}
728 	return 1;
729 }
730 
731 /*
732  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
733  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
734  * We need to be 1 filesystem block less than the 2^32 sector limit.
735  */
736 static loff_t ext2_max_size(int bits)
737 {
738 	loff_t res = EXT2_NDIR_BLOCKS;
739 	int meta_blocks;
740 	unsigned int upper_limit;
741 	unsigned int ppb = 1 << (bits-2);
742 
743 	/* This is calculated to be the largest file size for a
744 	 * dense, file such that the total number of
745 	 * sectors in the file, including data and all indirect blocks,
746 	 * does not exceed 2^32 -1
747 	 * __u32 i_blocks representing the total number of
748 	 * 512 bytes blocks of the file
749 	 */
750 	upper_limit = (1LL << 32) - 1;
751 
752 	/* total blocks in file system block size */
753 	upper_limit >>= (bits - 9);
754 
755 	/* Compute how many blocks we can address by block tree */
756 	res += 1LL << (bits-2);
757 	res += 1LL << (2*(bits-2));
758 	res += 1LL << (3*(bits-2));
759 	/* Does block tree limit file size? */
760 	if (res < upper_limit)
761 		goto check_lfs;
762 
763 	res = upper_limit;
764 	/* How many metadata blocks are needed for addressing upper_limit? */
765 	upper_limit -= EXT2_NDIR_BLOCKS;
766 	/* indirect blocks */
767 	meta_blocks = 1;
768 	upper_limit -= ppb;
769 	/* double indirect blocks */
770 	if (upper_limit < ppb * ppb) {
771 		meta_blocks += 1 + DIV_ROUND_UP(upper_limit, ppb);
772 		res -= meta_blocks;
773 		goto check_lfs;
774 	}
775 	meta_blocks += 1 + ppb;
776 	upper_limit -= ppb * ppb;
777 	/* tripple indirect blocks for the rest */
778 	meta_blocks += 1 + DIV_ROUND_UP(upper_limit, ppb) +
779 		DIV_ROUND_UP(upper_limit, ppb*ppb);
780 	res -= meta_blocks;
781 check_lfs:
782 	res <<= bits;
783 	if (res > MAX_LFS_FILESIZE)
784 		res = MAX_LFS_FILESIZE;
785 
786 	return res;
787 }
788 
789 static unsigned long descriptor_loc(struct super_block *sb,
790 				    unsigned long logic_sb_block,
791 				    int nr)
792 {
793 	struct ext2_sb_info *sbi = EXT2_SB(sb);
794 	unsigned long bg, first_meta_bg;
795 
796 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
797 
798 	if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
799 	    nr < first_meta_bg)
800 		return (logic_sb_block + nr + 1);
801 	bg = sbi->s_desc_per_block * nr;
802 
803 	return ext2_group_first_block_no(sb, bg) + ext2_bg_has_super(sb, bg);
804 }
805 
806 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
807 {
808 	struct dax_device *dax_dev = fs_dax_get_by_bdev(sb->s_bdev);
809 	struct buffer_head * bh;
810 	struct ext2_sb_info * sbi;
811 	struct ext2_super_block * es;
812 	struct inode *root;
813 	unsigned long block;
814 	unsigned long sb_block = get_sb_block(&data);
815 	unsigned long logic_sb_block;
816 	unsigned long offset = 0;
817 	unsigned long def_mount_opts;
818 	long ret = -ENOMEM;
819 	int blocksize = BLOCK_SIZE;
820 	int db_count;
821 	int i, j;
822 	__le32 features;
823 	int err;
824 	struct ext2_mount_options opts;
825 
826 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
827 	if (!sbi)
828 		goto failed;
829 
830 	sbi->s_blockgroup_lock =
831 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
832 	if (!sbi->s_blockgroup_lock) {
833 		kfree(sbi);
834 		goto failed;
835 	}
836 	sb->s_fs_info = sbi;
837 	sbi->s_sb_block = sb_block;
838 	sbi->s_daxdev = dax_dev;
839 
840 	spin_lock_init(&sbi->s_lock);
841 	ret = -EINVAL;
842 
843 	/*
844 	 * See what the current blocksize for the device is, and
845 	 * use that as the blocksize.  Otherwise (or if the blocksize
846 	 * is smaller than the default) use the default.
847 	 * This is important for devices that have a hardware
848 	 * sectorsize that is larger than the default.
849 	 */
850 	blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
851 	if (!blocksize) {
852 		ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
853 		goto failed_sbi;
854 	}
855 
856 	/*
857 	 * If the superblock doesn't start on a hardware sector boundary,
858 	 * calculate the offset.
859 	 */
860 	if (blocksize != BLOCK_SIZE) {
861 		logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
862 		offset = (sb_block*BLOCK_SIZE) % blocksize;
863 	} else {
864 		logic_sb_block = sb_block;
865 	}
866 
867 	if (!(bh = sb_bread(sb, logic_sb_block))) {
868 		ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
869 		goto failed_sbi;
870 	}
871 	/*
872 	 * Note: s_es must be initialized as soon as possible because
873 	 *       some ext2 macro-instructions depend on its value
874 	 */
875 	es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
876 	sbi->s_es = es;
877 	sb->s_magic = le16_to_cpu(es->s_magic);
878 
879 	if (sb->s_magic != EXT2_SUPER_MAGIC)
880 		goto cantfind_ext2;
881 
882 	opts.s_mount_opt = 0;
883 	/* Set defaults before we parse the mount options */
884 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
885 	if (def_mount_opts & EXT2_DEFM_DEBUG)
886 		set_opt(opts.s_mount_opt, DEBUG);
887 	if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
888 		set_opt(opts.s_mount_opt, GRPID);
889 	if (def_mount_opts & EXT2_DEFM_UID16)
890 		set_opt(opts.s_mount_opt, NO_UID32);
891 #ifdef CONFIG_EXT2_FS_XATTR
892 	if (def_mount_opts & EXT2_DEFM_XATTR_USER)
893 		set_opt(opts.s_mount_opt, XATTR_USER);
894 #endif
895 #ifdef CONFIG_EXT2_FS_POSIX_ACL
896 	if (def_mount_opts & EXT2_DEFM_ACL)
897 		set_opt(opts.s_mount_opt, POSIX_ACL);
898 #endif
899 
900 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
901 		set_opt(opts.s_mount_opt, ERRORS_PANIC);
902 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
903 		set_opt(opts.s_mount_opt, ERRORS_CONT);
904 	else
905 		set_opt(opts.s_mount_opt, ERRORS_RO);
906 
907 	opts.s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
908 	opts.s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
909 
910 	set_opt(opts.s_mount_opt, RESERVATION);
911 
912 	if (!parse_options((char *) data, sb, &opts))
913 		goto failed_mount;
914 
915 	sbi->s_mount_opt = opts.s_mount_opt;
916 	sbi->s_resuid = opts.s_resuid;
917 	sbi->s_resgid = opts.s_resgid;
918 
919 	sb->s_flags = (sb->s_flags & ~SB_POSIXACL) |
920 		(test_opt(sb, POSIX_ACL) ? SB_POSIXACL : 0);
921 	sb->s_iflags |= SB_I_CGROUPWB;
922 
923 	if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
924 	    (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
925 	     EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
926 	     EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
927 		ext2_msg(sb, KERN_WARNING,
928 			"warning: feature flags set on rev 0 fs, "
929 			"running e2fsck is recommended");
930 	/*
931 	 * Check feature flags regardless of the revision level, since we
932 	 * previously didn't change the revision level when setting the flags,
933 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
934 	 */
935 	features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
936 	if (features) {
937 		ext2_msg(sb, KERN_ERR,	"error: couldn't mount because of "
938 		       "unsupported optional features (%x)",
939 			le32_to_cpu(features));
940 		goto failed_mount;
941 	}
942 	if (!sb_rdonly(sb) && (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
943 		ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
944 		       "unsupported optional features (%x)",
945 		       le32_to_cpu(features));
946 		goto failed_mount;
947 	}
948 
949 	blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
950 
951 	if (test_opt(sb, DAX)) {
952 		if (!bdev_dax_supported(sb->s_bdev, blocksize)) {
953 			ext2_msg(sb, KERN_ERR,
954 				"DAX unsupported by block device. Turning off DAX.");
955 			clear_opt(sbi->s_mount_opt, DAX);
956 		}
957 	}
958 
959 	/* If the blocksize doesn't match, re-read the thing.. */
960 	if (sb->s_blocksize != blocksize) {
961 		brelse(bh);
962 
963 		if (!sb_set_blocksize(sb, blocksize)) {
964 			ext2_msg(sb, KERN_ERR,
965 				"error: bad blocksize %d", blocksize);
966 			goto failed_sbi;
967 		}
968 
969 		logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
970 		offset = (sb_block*BLOCK_SIZE) % blocksize;
971 		bh = sb_bread(sb, logic_sb_block);
972 		if(!bh) {
973 			ext2_msg(sb, KERN_ERR, "error: couldn't read"
974 				"superblock on 2nd try");
975 			goto failed_sbi;
976 		}
977 		es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
978 		sbi->s_es = es;
979 		if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
980 			ext2_msg(sb, KERN_ERR, "error: magic mismatch");
981 			goto failed_mount;
982 		}
983 	}
984 
985 	sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
986 	sb->s_max_links = EXT2_LINK_MAX;
987 	sb->s_time_min = S32_MIN;
988 	sb->s_time_max = S32_MAX;
989 
990 	if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
991 		sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
992 		sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
993 	} else {
994 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
995 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
996 		if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
997 		    !is_power_of_2(sbi->s_inode_size) ||
998 		    (sbi->s_inode_size > blocksize)) {
999 			ext2_msg(sb, KERN_ERR,
1000 				"error: unsupported inode size: %d",
1001 				sbi->s_inode_size);
1002 			goto failed_mount;
1003 		}
1004 	}
1005 
1006 	sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
1007 				   le32_to_cpu(es->s_log_frag_size);
1008 	if (sbi->s_frag_size == 0)
1009 		goto cantfind_ext2;
1010 	sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
1011 
1012 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
1013 	sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
1014 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
1015 
1016 	sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
1017 	if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
1018 		goto cantfind_ext2;
1019 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
1020 					sbi->s_inodes_per_block;
1021 	sbi->s_desc_per_block = sb->s_blocksize /
1022 					sizeof (struct ext2_group_desc);
1023 	sbi->s_sbh = bh;
1024 	sbi->s_mount_state = le16_to_cpu(es->s_state);
1025 	sbi->s_addr_per_block_bits =
1026 		ilog2 (EXT2_ADDR_PER_BLOCK(sb));
1027 	sbi->s_desc_per_block_bits =
1028 		ilog2 (EXT2_DESC_PER_BLOCK(sb));
1029 
1030 	if (sb->s_magic != EXT2_SUPER_MAGIC)
1031 		goto cantfind_ext2;
1032 
1033 	if (sb->s_blocksize != bh->b_size) {
1034 		if (!silent)
1035 			ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
1036 		goto failed_mount;
1037 	}
1038 
1039 	if (sb->s_blocksize != sbi->s_frag_size) {
1040 		ext2_msg(sb, KERN_ERR,
1041 			"error: fragsize %lu != blocksize %lu"
1042 			"(not supported yet)",
1043 			sbi->s_frag_size, sb->s_blocksize);
1044 		goto failed_mount;
1045 	}
1046 
1047 	if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
1048 		ext2_msg(sb, KERN_ERR,
1049 			"error: #blocks per group too big: %lu",
1050 			sbi->s_blocks_per_group);
1051 		goto failed_mount;
1052 	}
1053 	if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
1054 		ext2_msg(sb, KERN_ERR,
1055 			"error: #fragments per group too big: %lu",
1056 			sbi->s_frags_per_group);
1057 		goto failed_mount;
1058 	}
1059 	if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
1060 		ext2_msg(sb, KERN_ERR,
1061 			"error: #inodes per group too big: %lu",
1062 			sbi->s_inodes_per_group);
1063 		goto failed_mount;
1064 	}
1065 
1066 	if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
1067 		goto cantfind_ext2;
1068 	sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
1069 				le32_to_cpu(es->s_first_data_block) - 1)
1070 					/ EXT2_BLOCKS_PER_GROUP(sb)) + 1;
1071 	db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
1072 		   EXT2_DESC_PER_BLOCK(sb);
1073 	sbi->s_group_desc = kmalloc_array (db_count,
1074 					   sizeof(struct buffer_head *),
1075 					   GFP_KERNEL);
1076 	if (sbi->s_group_desc == NULL) {
1077 		ret = -ENOMEM;
1078 		ext2_msg(sb, KERN_ERR, "error: not enough memory");
1079 		goto failed_mount;
1080 	}
1081 	bgl_lock_init(sbi->s_blockgroup_lock);
1082 	sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1083 	if (!sbi->s_debts) {
1084 		ret = -ENOMEM;
1085 		ext2_msg(sb, KERN_ERR, "error: not enough memory");
1086 		goto failed_mount_group_desc;
1087 	}
1088 	for (i = 0; i < db_count; i++) {
1089 		block = descriptor_loc(sb, logic_sb_block, i);
1090 		sbi->s_group_desc[i] = sb_bread(sb, block);
1091 		if (!sbi->s_group_desc[i]) {
1092 			for (j = 0; j < i; j++)
1093 				brelse (sbi->s_group_desc[j]);
1094 			ext2_msg(sb, KERN_ERR,
1095 				"error: unable to read group descriptors");
1096 			goto failed_mount_group_desc;
1097 		}
1098 	}
1099 	if (!ext2_check_descriptors (sb)) {
1100 		ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1101 		goto failed_mount2;
1102 	}
1103 	sbi->s_gdb_count = db_count;
1104 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1105 	spin_lock_init(&sbi->s_next_gen_lock);
1106 
1107 	/* per fileystem reservation list head & lock */
1108 	spin_lock_init(&sbi->s_rsv_window_lock);
1109 	sbi->s_rsv_window_root = RB_ROOT;
1110 	/*
1111 	 * Add a single, static dummy reservation to the start of the
1112 	 * reservation window list --- it gives us a placeholder for
1113 	 * append-at-start-of-list which makes the allocation logic
1114 	 * _much_ simpler.
1115 	 */
1116 	sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1117 	sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1118 	sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1119 	sbi->s_rsv_window_head.rsv_goal_size = 0;
1120 	ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1121 
1122 	err = percpu_counter_init(&sbi->s_freeblocks_counter,
1123 				ext2_count_free_blocks(sb), GFP_KERNEL);
1124 	if (!err) {
1125 		err = percpu_counter_init(&sbi->s_freeinodes_counter,
1126 				ext2_count_free_inodes(sb), GFP_KERNEL);
1127 	}
1128 	if (!err) {
1129 		err = percpu_counter_init(&sbi->s_dirs_counter,
1130 				ext2_count_dirs(sb), GFP_KERNEL);
1131 	}
1132 	if (err) {
1133 		ret = err;
1134 		ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1135 		goto failed_mount3;
1136 	}
1137 
1138 #ifdef CONFIG_EXT2_FS_XATTR
1139 	sbi->s_ea_block_cache = ext2_xattr_create_cache();
1140 	if (!sbi->s_ea_block_cache) {
1141 		ret = -ENOMEM;
1142 		ext2_msg(sb, KERN_ERR, "Failed to create ea_block_cache");
1143 		goto failed_mount3;
1144 	}
1145 #endif
1146 	/*
1147 	 * set up enough so that it can read an inode
1148 	 */
1149 	sb->s_op = &ext2_sops;
1150 	sb->s_export_op = &ext2_export_ops;
1151 	sb->s_xattr = ext2_xattr_handlers;
1152 
1153 #ifdef CONFIG_QUOTA
1154 	sb->dq_op = &dquot_operations;
1155 	sb->s_qcop = &ext2_quotactl_ops;
1156 	sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP;
1157 #endif
1158 
1159 	root = ext2_iget(sb, EXT2_ROOT_INO);
1160 	if (IS_ERR(root)) {
1161 		ret = PTR_ERR(root);
1162 		goto failed_mount3;
1163 	}
1164 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1165 		iput(root);
1166 		ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1167 		goto failed_mount3;
1168 	}
1169 
1170 	sb->s_root = d_make_root(root);
1171 	if (!sb->s_root) {
1172 		ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1173 		ret = -ENOMEM;
1174 		goto failed_mount3;
1175 	}
1176 	if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1177 		ext2_msg(sb, KERN_WARNING,
1178 			"warning: mounting ext3 filesystem as ext2");
1179 	if (ext2_setup_super (sb, es, sb_rdonly(sb)))
1180 		sb->s_flags |= SB_RDONLY;
1181 	ext2_write_super(sb);
1182 	return 0;
1183 
1184 cantfind_ext2:
1185 	if (!silent)
1186 		ext2_msg(sb, KERN_ERR,
1187 			"error: can't find an ext2 filesystem on dev %s.",
1188 			sb->s_id);
1189 	goto failed_mount;
1190 failed_mount3:
1191 	ext2_xattr_destroy_cache(sbi->s_ea_block_cache);
1192 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
1193 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
1194 	percpu_counter_destroy(&sbi->s_dirs_counter);
1195 failed_mount2:
1196 	for (i = 0; i < db_count; i++)
1197 		brelse(sbi->s_group_desc[i]);
1198 failed_mount_group_desc:
1199 	kfree(sbi->s_group_desc);
1200 	kfree(sbi->s_debts);
1201 failed_mount:
1202 	brelse(bh);
1203 failed_sbi:
1204 	sb->s_fs_info = NULL;
1205 	kfree(sbi->s_blockgroup_lock);
1206 	kfree(sbi);
1207 failed:
1208 	fs_put_dax(dax_dev);
1209 	return ret;
1210 }
1211 
1212 static void ext2_clear_super_error(struct super_block *sb)
1213 {
1214 	struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1215 
1216 	if (buffer_write_io_error(sbh)) {
1217 		/*
1218 		 * Oh, dear.  A previous attempt to write the
1219 		 * superblock failed.  This could happen because the
1220 		 * USB device was yanked out.  Or it could happen to
1221 		 * be a transient write error and maybe the block will
1222 		 * be remapped.  Nothing we can do but to retry the
1223 		 * write and hope for the best.
1224 		 */
1225 		ext2_msg(sb, KERN_ERR,
1226 		       "previous I/O error to superblock detected");
1227 		clear_buffer_write_io_error(sbh);
1228 		set_buffer_uptodate(sbh);
1229 	}
1230 }
1231 
1232 void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1233 		     int wait)
1234 {
1235 	ext2_clear_super_error(sb);
1236 	spin_lock(&EXT2_SB(sb)->s_lock);
1237 	es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1238 	es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1239 	es->s_wtime = cpu_to_le32(ktime_get_real_seconds());
1240 	/* unlock before we do IO */
1241 	spin_unlock(&EXT2_SB(sb)->s_lock);
1242 	mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1243 	if (wait)
1244 		sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1245 }
1246 
1247 /*
1248  * In the second extended file system, it is not necessary to
1249  * write the super block since we use a mapping of the
1250  * disk super block in a buffer.
1251  *
1252  * However, this function is still used to set the fs valid
1253  * flags to 0.  We need to set this flag to 0 since the fs
1254  * may have been checked while mounted and e2fsck may have
1255  * set s_state to EXT2_VALID_FS after some corrections.
1256  */
1257 static int ext2_sync_fs(struct super_block *sb, int wait)
1258 {
1259 	struct ext2_sb_info *sbi = EXT2_SB(sb);
1260 	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1261 
1262 	/*
1263 	 * Write quota structures to quota file, sync_blockdev() will write
1264 	 * them to disk later
1265 	 */
1266 	dquot_writeback_dquots(sb, -1);
1267 
1268 	spin_lock(&sbi->s_lock);
1269 	if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1270 		ext2_debug("setting valid to 0\n");
1271 		es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1272 	}
1273 	spin_unlock(&sbi->s_lock);
1274 	ext2_sync_super(sb, es, wait);
1275 	return 0;
1276 }
1277 
1278 static int ext2_freeze(struct super_block *sb)
1279 {
1280 	struct ext2_sb_info *sbi = EXT2_SB(sb);
1281 
1282 	/*
1283 	 * Open but unlinked files present? Keep EXT2_VALID_FS flag cleared
1284 	 * because we have unattached inodes and thus filesystem is not fully
1285 	 * consistent.
1286 	 */
1287 	if (atomic_long_read(&sb->s_remove_count)) {
1288 		ext2_sync_fs(sb, 1);
1289 		return 0;
1290 	}
1291 	/* Set EXT2_FS_VALID flag */
1292 	spin_lock(&sbi->s_lock);
1293 	sbi->s_es->s_state = cpu_to_le16(sbi->s_mount_state);
1294 	spin_unlock(&sbi->s_lock);
1295 	ext2_sync_super(sb, sbi->s_es, 1);
1296 
1297 	return 0;
1298 }
1299 
1300 static int ext2_unfreeze(struct super_block *sb)
1301 {
1302 	/* Just write sb to clear EXT2_VALID_FS flag */
1303 	ext2_write_super(sb);
1304 
1305 	return 0;
1306 }
1307 
1308 static void ext2_write_super(struct super_block *sb)
1309 {
1310 	if (!sb_rdonly(sb))
1311 		ext2_sync_fs(sb, 1);
1312 }
1313 
1314 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1315 {
1316 	struct ext2_sb_info * sbi = EXT2_SB(sb);
1317 	struct ext2_super_block * es;
1318 	struct ext2_mount_options new_opts;
1319 	int err;
1320 
1321 	sync_filesystem(sb);
1322 
1323 	spin_lock(&sbi->s_lock);
1324 	new_opts.s_mount_opt = sbi->s_mount_opt;
1325 	new_opts.s_resuid = sbi->s_resuid;
1326 	new_opts.s_resgid = sbi->s_resgid;
1327 	spin_unlock(&sbi->s_lock);
1328 
1329 	if (!parse_options(data, sb, &new_opts))
1330 		return -EINVAL;
1331 
1332 	spin_lock(&sbi->s_lock);
1333 	es = sbi->s_es;
1334 	if ((sbi->s_mount_opt ^ new_opts.s_mount_opt) & EXT2_MOUNT_DAX) {
1335 		ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1336 			 "dax flag with busy inodes while remounting");
1337 		new_opts.s_mount_opt ^= EXT2_MOUNT_DAX;
1338 	}
1339 	if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1340 		goto out_set;
1341 	if (*flags & SB_RDONLY) {
1342 		if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1343 		    !(sbi->s_mount_state & EXT2_VALID_FS))
1344 			goto out_set;
1345 
1346 		/*
1347 		 * OK, we are remounting a valid rw partition rdonly, so set
1348 		 * the rdonly flag and then mark the partition as valid again.
1349 		 */
1350 		es->s_state = cpu_to_le16(sbi->s_mount_state);
1351 		es->s_mtime = cpu_to_le32(ktime_get_real_seconds());
1352 		spin_unlock(&sbi->s_lock);
1353 
1354 		err = dquot_suspend(sb, -1);
1355 		if (err < 0)
1356 			return err;
1357 
1358 		ext2_sync_super(sb, es, 1);
1359 	} else {
1360 		__le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1361 					       ~EXT2_FEATURE_RO_COMPAT_SUPP);
1362 		if (ret) {
1363 			spin_unlock(&sbi->s_lock);
1364 			ext2_msg(sb, KERN_WARNING,
1365 				"warning: couldn't remount RDWR because of "
1366 				"unsupported optional features (%x).",
1367 				le32_to_cpu(ret));
1368 			return -EROFS;
1369 		}
1370 		/*
1371 		 * Mounting a RDONLY partition read-write, so reread and
1372 		 * store the current valid flag.  (It may have been changed
1373 		 * by e2fsck since we originally mounted the partition.)
1374 		 */
1375 		sbi->s_mount_state = le16_to_cpu(es->s_state);
1376 		if (!ext2_setup_super (sb, es, 0))
1377 			sb->s_flags &= ~SB_RDONLY;
1378 		spin_unlock(&sbi->s_lock);
1379 
1380 		ext2_write_super(sb);
1381 
1382 		dquot_resume(sb, -1);
1383 	}
1384 
1385 	spin_lock(&sbi->s_lock);
1386 out_set:
1387 	sbi->s_mount_opt = new_opts.s_mount_opt;
1388 	sbi->s_resuid = new_opts.s_resuid;
1389 	sbi->s_resgid = new_opts.s_resgid;
1390 	sb->s_flags = (sb->s_flags & ~SB_POSIXACL) |
1391 		(test_opt(sb, POSIX_ACL) ? SB_POSIXACL : 0);
1392 	spin_unlock(&sbi->s_lock);
1393 
1394 	return 0;
1395 }
1396 
1397 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1398 {
1399 	struct super_block *sb = dentry->d_sb;
1400 	struct ext2_sb_info *sbi = EXT2_SB(sb);
1401 	struct ext2_super_block *es = sbi->s_es;
1402 	u64 fsid;
1403 
1404 	spin_lock(&sbi->s_lock);
1405 
1406 	if (test_opt (sb, MINIX_DF))
1407 		sbi->s_overhead_last = 0;
1408 	else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1409 		unsigned long i, overhead = 0;
1410 		smp_rmb();
1411 
1412 		/*
1413 		 * Compute the overhead (FS structures). This is constant
1414 		 * for a given filesystem unless the number of block groups
1415 		 * changes so we cache the previous value until it does.
1416 		 */
1417 
1418 		/*
1419 		 * All of the blocks before first_data_block are
1420 		 * overhead
1421 		 */
1422 		overhead = le32_to_cpu(es->s_first_data_block);
1423 
1424 		/*
1425 		 * Add the overhead attributed to the superblock and
1426 		 * block group descriptors.  If the sparse superblocks
1427 		 * feature is turned on, then not all groups have this.
1428 		 */
1429 		for (i = 0; i < sbi->s_groups_count; i++)
1430 			overhead += ext2_bg_has_super(sb, i) +
1431 				ext2_bg_num_gdb(sb, i);
1432 
1433 		/*
1434 		 * Every block group has an inode bitmap, a block
1435 		 * bitmap, and an inode table.
1436 		 */
1437 		overhead += (sbi->s_groups_count *
1438 			     (2 + sbi->s_itb_per_group));
1439 		sbi->s_overhead_last = overhead;
1440 		smp_wmb();
1441 		sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1442 	}
1443 
1444 	buf->f_type = EXT2_SUPER_MAGIC;
1445 	buf->f_bsize = sb->s_blocksize;
1446 	buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1447 	buf->f_bfree = ext2_count_free_blocks(sb);
1448 	es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1449 	buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1450 	if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1451 		buf->f_bavail = 0;
1452 	buf->f_files = le32_to_cpu(es->s_inodes_count);
1453 	buf->f_ffree = ext2_count_free_inodes(sb);
1454 	es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1455 	buf->f_namelen = EXT2_NAME_LEN;
1456 	fsid = le64_to_cpup((void *)es->s_uuid) ^
1457 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1458 	buf->f_fsid = u64_to_fsid(fsid);
1459 	spin_unlock(&sbi->s_lock);
1460 	return 0;
1461 }
1462 
1463 static struct dentry *ext2_mount(struct file_system_type *fs_type,
1464 	int flags, const char *dev_name, void *data)
1465 {
1466 	return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1467 }
1468 
1469 #ifdef CONFIG_QUOTA
1470 
1471 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1472  * acquiring the locks... As quota files are never truncated and quota code
1473  * itself serializes the operations (and no one else should touch the files)
1474  * we don't have to be afraid of races */
1475 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1476 			       size_t len, loff_t off)
1477 {
1478 	struct inode *inode = sb_dqopt(sb)->files[type];
1479 	sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1480 	int err = 0;
1481 	int offset = off & (sb->s_blocksize - 1);
1482 	int tocopy;
1483 	size_t toread;
1484 	struct buffer_head tmp_bh;
1485 	struct buffer_head *bh;
1486 	loff_t i_size = i_size_read(inode);
1487 
1488 	if (off > i_size)
1489 		return 0;
1490 	if (off+len > i_size)
1491 		len = i_size-off;
1492 	toread = len;
1493 	while (toread > 0) {
1494 		tocopy = sb->s_blocksize - offset < toread ?
1495 				sb->s_blocksize - offset : toread;
1496 
1497 		tmp_bh.b_state = 0;
1498 		tmp_bh.b_size = sb->s_blocksize;
1499 		err = ext2_get_block(inode, blk, &tmp_bh, 0);
1500 		if (err < 0)
1501 			return err;
1502 		if (!buffer_mapped(&tmp_bh))	/* A hole? */
1503 			memset(data, 0, tocopy);
1504 		else {
1505 			bh = sb_bread(sb, tmp_bh.b_blocknr);
1506 			if (!bh)
1507 				return -EIO;
1508 			memcpy(data, bh->b_data+offset, tocopy);
1509 			brelse(bh);
1510 		}
1511 		offset = 0;
1512 		toread -= tocopy;
1513 		data += tocopy;
1514 		blk++;
1515 	}
1516 	return len;
1517 }
1518 
1519 /* Write to quotafile */
1520 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1521 				const char *data, size_t len, loff_t off)
1522 {
1523 	struct inode *inode = sb_dqopt(sb)->files[type];
1524 	sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1525 	int err = 0;
1526 	int offset = off & (sb->s_blocksize - 1);
1527 	int tocopy;
1528 	size_t towrite = len;
1529 	struct buffer_head tmp_bh;
1530 	struct buffer_head *bh;
1531 
1532 	while (towrite > 0) {
1533 		tocopy = sb->s_blocksize - offset < towrite ?
1534 				sb->s_blocksize - offset : towrite;
1535 
1536 		tmp_bh.b_state = 0;
1537 		tmp_bh.b_size = sb->s_blocksize;
1538 		err = ext2_get_block(inode, blk, &tmp_bh, 1);
1539 		if (err < 0)
1540 			goto out;
1541 		if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1542 			bh = sb_bread(sb, tmp_bh.b_blocknr);
1543 		else
1544 			bh = sb_getblk(sb, tmp_bh.b_blocknr);
1545 		if (unlikely(!bh)) {
1546 			err = -EIO;
1547 			goto out;
1548 		}
1549 		lock_buffer(bh);
1550 		memcpy(bh->b_data+offset, data, tocopy);
1551 		flush_dcache_page(bh->b_page);
1552 		set_buffer_uptodate(bh);
1553 		mark_buffer_dirty(bh);
1554 		unlock_buffer(bh);
1555 		brelse(bh);
1556 		offset = 0;
1557 		towrite -= tocopy;
1558 		data += tocopy;
1559 		blk++;
1560 	}
1561 out:
1562 	if (len == towrite)
1563 		return err;
1564 	if (inode->i_size < off+len-towrite)
1565 		i_size_write(inode, off+len-towrite);
1566 	inode_inc_iversion(inode);
1567 	inode->i_mtime = inode->i_ctime = current_time(inode);
1568 	mark_inode_dirty(inode);
1569 	return len - towrite;
1570 }
1571 
1572 static int ext2_quota_on(struct super_block *sb, int type, int format_id,
1573 			 const struct path *path)
1574 {
1575 	int err;
1576 	struct inode *inode;
1577 
1578 	err = dquot_quota_on(sb, type, format_id, path);
1579 	if (err)
1580 		return err;
1581 
1582 	inode = d_inode(path->dentry);
1583 	inode_lock(inode);
1584 	EXT2_I(inode)->i_flags |= EXT2_NOATIME_FL | EXT2_IMMUTABLE_FL;
1585 	inode_set_flags(inode, S_NOATIME | S_IMMUTABLE,
1586 			S_NOATIME | S_IMMUTABLE);
1587 	inode_unlock(inode);
1588 	mark_inode_dirty(inode);
1589 
1590 	return 0;
1591 }
1592 
1593 static int ext2_quota_off(struct super_block *sb, int type)
1594 {
1595 	struct inode *inode = sb_dqopt(sb)->files[type];
1596 	int err;
1597 
1598 	if (!inode || !igrab(inode))
1599 		goto out;
1600 
1601 	err = dquot_quota_off(sb, type);
1602 	if (err)
1603 		goto out_put;
1604 
1605 	inode_lock(inode);
1606 	EXT2_I(inode)->i_flags &= ~(EXT2_NOATIME_FL | EXT2_IMMUTABLE_FL);
1607 	inode_set_flags(inode, 0, S_NOATIME | S_IMMUTABLE);
1608 	inode_unlock(inode);
1609 	mark_inode_dirty(inode);
1610 out_put:
1611 	iput(inode);
1612 	return err;
1613 out:
1614 	return dquot_quota_off(sb, type);
1615 }
1616 
1617 #endif
1618 
1619 static struct file_system_type ext2_fs_type = {
1620 	.owner		= THIS_MODULE,
1621 	.name		= "ext2",
1622 	.mount		= ext2_mount,
1623 	.kill_sb	= kill_block_super,
1624 	.fs_flags	= FS_REQUIRES_DEV,
1625 };
1626 MODULE_ALIAS_FS("ext2");
1627 
1628 static int __init init_ext2_fs(void)
1629 {
1630 	int err;
1631 
1632 	err = init_inodecache();
1633 	if (err)
1634 		return err;
1635         err = register_filesystem(&ext2_fs_type);
1636 	if (err)
1637 		goto out;
1638 	return 0;
1639 out:
1640 	destroy_inodecache();
1641 	return err;
1642 }
1643 
1644 static void __exit exit_ext2_fs(void)
1645 {
1646 	unregister_filesystem(&ext2_fs_type);
1647 	destroy_inodecache();
1648 }
1649 
1650 MODULE_AUTHOR("Remy Card and others");
1651 MODULE_DESCRIPTION("Second Extended Filesystem");
1652 MODULE_LICENSE("GPL");
1653 module_init(init_ext2_fs)
1654 module_exit(exit_ext2_fs)
1655