xref: /openbmc/linux/fs/ext2/super.c (revision 5b4cb650)
1 /*
2  *  linux/fs/ext2/super.c
3  *
4  * Copyright (C) 1992, 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  *
9  *  from
10  *
11  *  linux/fs/minix/inode.c
12  *
13  *  Copyright (C) 1991, 1992  Linus Torvalds
14  *
15  *  Big-endian to little-endian byte-swapping/bitmaps by
16  *        David S. Miller (davem@caip.rutgers.edu), 1995
17  */
18 
19 #include <linux/module.h>
20 #include <linux/string.h>
21 #include <linux/fs.h>
22 #include <linux/slab.h>
23 #include <linux/init.h>
24 #include <linux/blkdev.h>
25 #include <linux/parser.h>
26 #include <linux/random.h>
27 #include <linux/buffer_head.h>
28 #include <linux/exportfs.h>
29 #include <linux/vfs.h>
30 #include <linux/seq_file.h>
31 #include <linux/mount.h>
32 #include <linux/log2.h>
33 #include <linux/quotaops.h>
34 #include <linux/uaccess.h>
35 #include <linux/dax.h>
36 #include <linux/iversion.h>
37 #include "ext2.h"
38 #include "xattr.h"
39 #include "acl.h"
40 
41 static void ext2_write_super(struct super_block *sb);
42 static int ext2_remount (struct super_block * sb, int * flags, char * data);
43 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
44 static int ext2_sync_fs(struct super_block *sb, int wait);
45 static int ext2_freeze(struct super_block *sb);
46 static int ext2_unfreeze(struct super_block *sb);
47 
48 void ext2_error(struct super_block *sb, const char *function,
49 		const char *fmt, ...)
50 {
51 	struct va_format vaf;
52 	va_list args;
53 	struct ext2_sb_info *sbi = EXT2_SB(sb);
54 	struct ext2_super_block *es = sbi->s_es;
55 
56 	if (!sb_rdonly(sb)) {
57 		spin_lock(&sbi->s_lock);
58 		sbi->s_mount_state |= EXT2_ERROR_FS;
59 		es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
60 		spin_unlock(&sbi->s_lock);
61 		ext2_sync_super(sb, es, 1);
62 	}
63 
64 	va_start(args, fmt);
65 
66 	vaf.fmt = fmt;
67 	vaf.va = &args;
68 
69 	printk(KERN_CRIT "EXT2-fs (%s): error: %s: %pV\n",
70 	       sb->s_id, function, &vaf);
71 
72 	va_end(args);
73 
74 	if (test_opt(sb, ERRORS_PANIC))
75 		panic("EXT2-fs: panic from previous error\n");
76 	if (!sb_rdonly(sb) && test_opt(sb, ERRORS_RO)) {
77 		ext2_msg(sb, KERN_CRIT,
78 			     "error: remounting filesystem read-only");
79 		sb->s_flags |= SB_RDONLY;
80 	}
81 }
82 
83 void ext2_msg(struct super_block *sb, const char *prefix,
84 		const char *fmt, ...)
85 {
86 	struct va_format vaf;
87 	va_list args;
88 
89 	va_start(args, fmt);
90 
91 	vaf.fmt = fmt;
92 	vaf.va = &args;
93 
94 	printk("%sEXT2-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
95 
96 	va_end(args);
97 }
98 
99 /*
100  * This must be called with sbi->s_lock held.
101  */
102 void ext2_update_dynamic_rev(struct super_block *sb)
103 {
104 	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
105 
106 	if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
107 		return;
108 
109 	ext2_msg(sb, KERN_WARNING,
110 		     "warning: updating to rev %d because of "
111 		     "new feature flag, running e2fsck is recommended",
112 		     EXT2_DYNAMIC_REV);
113 
114 	es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
115 	es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
116 	es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
117 	/* leave es->s_feature_*compat flags alone */
118 	/* es->s_uuid will be set by e2fsck if empty */
119 
120 	/*
121 	 * The rest of the superblock fields should be zero, and if not it
122 	 * means they are likely already in use, so leave them alone.  We
123 	 * can leave it up to e2fsck to clean up any inconsistencies there.
124 	 */
125 }
126 
127 #ifdef CONFIG_QUOTA
128 static int ext2_quota_off(struct super_block *sb, int type);
129 
130 static void ext2_quota_off_umount(struct super_block *sb)
131 {
132 	int type;
133 
134 	for (type = 0; type < MAXQUOTAS; type++)
135 		ext2_quota_off(sb, type);
136 }
137 #else
138 static inline void ext2_quota_off_umount(struct super_block *sb)
139 {
140 }
141 #endif
142 
143 static void ext2_put_super (struct super_block * sb)
144 {
145 	int db_count;
146 	int i;
147 	struct ext2_sb_info *sbi = EXT2_SB(sb);
148 
149 	ext2_quota_off_umount(sb);
150 
151 	ext2_xattr_destroy_cache(sbi->s_ea_block_cache);
152 	sbi->s_ea_block_cache = NULL;
153 
154 	if (!sb_rdonly(sb)) {
155 		struct ext2_super_block *es = sbi->s_es;
156 
157 		spin_lock(&sbi->s_lock);
158 		es->s_state = cpu_to_le16(sbi->s_mount_state);
159 		spin_unlock(&sbi->s_lock);
160 		ext2_sync_super(sb, es, 1);
161 	}
162 	db_count = sbi->s_gdb_count;
163 	for (i = 0; i < db_count; i++)
164 		if (sbi->s_group_desc[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_i_callback(struct rcu_head *head)
196 {
197 	struct inode *inode = container_of(head, struct inode, i_rcu);
198 	kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
199 }
200 
201 static void ext2_destroy_inode(struct inode *inode)
202 {
203 	call_rcu(&inode->i_rcu, ext2_i_callback);
204 }
205 
206 static void init_once(void *foo)
207 {
208 	struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
209 
210 	rwlock_init(&ei->i_meta_lock);
211 #ifdef CONFIG_EXT2_FS_XATTR
212 	init_rwsem(&ei->xattr_sem);
213 #endif
214 	mutex_init(&ei->truncate_mutex);
215 #ifdef CONFIG_FS_DAX
216 	init_rwsem(&ei->dax_sem);
217 #endif
218 	inode_init_once(&ei->vfs_inode);
219 }
220 
221 static int __init init_inodecache(void)
222 {
223 	ext2_inode_cachep = kmem_cache_create_usercopy("ext2_inode_cache",
224 				sizeof(struct ext2_inode_info), 0,
225 				(SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
226 					SLAB_ACCOUNT),
227 				offsetof(struct ext2_inode_info, i_data),
228 				sizeof_field(struct ext2_inode_info, i_data),
229 				init_once);
230 	if (ext2_inode_cachep == NULL)
231 		return -ENOMEM;
232 	return 0;
233 }
234 
235 static void destroy_inodecache(void)
236 {
237 	/*
238 	 * Make sure all delayed rcu free inodes are flushed before we
239 	 * destroy cache.
240 	 */
241 	rcu_barrier();
242 	kmem_cache_destroy(ext2_inode_cachep);
243 }
244 
245 static int ext2_show_options(struct seq_file *seq, struct dentry *root)
246 {
247 	struct super_block *sb = root->d_sb;
248 	struct ext2_sb_info *sbi = EXT2_SB(sb);
249 	struct ext2_super_block *es = sbi->s_es;
250 	unsigned long def_mount_opts;
251 
252 	spin_lock(&sbi->s_lock);
253 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
254 
255 	if (sbi->s_sb_block != 1)
256 		seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
257 	if (test_opt(sb, MINIX_DF))
258 		seq_puts(seq, ",minixdf");
259 	if (test_opt(sb, GRPID))
260 		seq_puts(seq, ",grpid");
261 	if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
262 		seq_puts(seq, ",nogrpid");
263 	if (!uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT2_DEF_RESUID)) ||
264 	    le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
265 		seq_printf(seq, ",resuid=%u",
266 				from_kuid_munged(&init_user_ns, sbi->s_resuid));
267 	}
268 	if (!gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT2_DEF_RESGID)) ||
269 	    le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
270 		seq_printf(seq, ",resgid=%u",
271 				from_kgid_munged(&init_user_ns, sbi->s_resgid));
272 	}
273 	if (test_opt(sb, ERRORS_RO)) {
274 		int def_errors = le16_to_cpu(es->s_errors);
275 
276 		if (def_errors == EXT2_ERRORS_PANIC ||
277 		    def_errors == EXT2_ERRORS_CONTINUE) {
278 			seq_puts(seq, ",errors=remount-ro");
279 		}
280 	}
281 	if (test_opt(sb, ERRORS_CONT))
282 		seq_puts(seq, ",errors=continue");
283 	if (test_opt(sb, ERRORS_PANIC))
284 		seq_puts(seq, ",errors=panic");
285 	if (test_opt(sb, NO_UID32))
286 		seq_puts(seq, ",nouid32");
287 	if (test_opt(sb, DEBUG))
288 		seq_puts(seq, ",debug");
289 	if (test_opt(sb, OLDALLOC))
290 		seq_puts(seq, ",oldalloc");
291 
292 #ifdef CONFIG_EXT2_FS_XATTR
293 	if (test_opt(sb, XATTR_USER))
294 		seq_puts(seq, ",user_xattr");
295 	if (!test_opt(sb, XATTR_USER) &&
296 	    (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
297 		seq_puts(seq, ",nouser_xattr");
298 	}
299 #endif
300 
301 #ifdef CONFIG_EXT2_FS_POSIX_ACL
302 	if (test_opt(sb, POSIX_ACL))
303 		seq_puts(seq, ",acl");
304 	if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
305 		seq_puts(seq, ",noacl");
306 #endif
307 
308 	if (test_opt(sb, NOBH))
309 		seq_puts(seq, ",nobh");
310 
311 	if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
312 		seq_puts(seq, ",usrquota");
313 
314 	if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
315 		seq_puts(seq, ",grpquota");
316 
317 	if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
318 		seq_puts(seq, ",xip");
319 
320 	if (sbi->s_mount_opt & EXT2_MOUNT_DAX)
321 		seq_puts(seq, ",dax");
322 
323 	if (!test_opt(sb, RESERVATION))
324 		seq_puts(seq, ",noreservation");
325 
326 	spin_unlock(&sbi->s_lock);
327 	return 0;
328 }
329 
330 #ifdef CONFIG_QUOTA
331 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
332 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
333 static int ext2_quota_on(struct super_block *sb, int type, int format_id,
334 			 const struct path *path);
335 static struct dquot **ext2_get_dquots(struct inode *inode)
336 {
337 	return EXT2_I(inode)->i_dquot;
338 }
339 
340 static const struct quotactl_ops ext2_quotactl_ops = {
341 	.quota_on	= ext2_quota_on,
342 	.quota_off	= ext2_quota_off,
343 	.quota_sync	= dquot_quota_sync,
344 	.get_state	= dquot_get_state,
345 	.set_info	= dquot_set_dqinfo,
346 	.get_dqblk	= dquot_get_dqblk,
347 	.set_dqblk	= dquot_set_dqblk,
348 	.get_nextdqblk	= dquot_get_next_dqblk,
349 };
350 #endif
351 
352 static const struct super_operations ext2_sops = {
353 	.alloc_inode	= ext2_alloc_inode,
354 	.destroy_inode	= ext2_destroy_inode,
355 	.write_inode	= ext2_write_inode,
356 	.evict_inode	= ext2_evict_inode,
357 	.put_super	= ext2_put_super,
358 	.sync_fs	= ext2_sync_fs,
359 	.freeze_fs	= ext2_freeze,
360 	.unfreeze_fs	= ext2_unfreeze,
361 	.statfs		= ext2_statfs,
362 	.remount_fs	= ext2_remount,
363 	.show_options	= ext2_show_options,
364 #ifdef CONFIG_QUOTA
365 	.quota_read	= ext2_quota_read,
366 	.quota_write	= ext2_quota_write,
367 	.get_dquots	= ext2_get_dquots,
368 #endif
369 };
370 
371 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
372 		u64 ino, u32 generation)
373 {
374 	struct inode *inode;
375 
376 	if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
377 		return ERR_PTR(-ESTALE);
378 	if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
379 		return ERR_PTR(-ESTALE);
380 
381 	/*
382 	 * ext2_iget isn't quite right if the inode is currently unallocated!
383 	 * However ext2_iget currently does appropriate checks to handle stale
384 	 * inodes so everything is OK.
385 	 */
386 	inode = ext2_iget(sb, ino);
387 	if (IS_ERR(inode))
388 		return ERR_CAST(inode);
389 	if (generation && inode->i_generation != generation) {
390 		/* we didn't find the right inode.. */
391 		iput(inode);
392 		return ERR_PTR(-ESTALE);
393 	}
394 	return inode;
395 }
396 
397 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
398 		int fh_len, int fh_type)
399 {
400 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
401 				    ext2_nfs_get_inode);
402 }
403 
404 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
405 		int fh_len, int fh_type)
406 {
407 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
408 				    ext2_nfs_get_inode);
409 }
410 
411 static const struct export_operations ext2_export_ops = {
412 	.fh_to_dentry = ext2_fh_to_dentry,
413 	.fh_to_parent = ext2_fh_to_parent,
414 	.get_parent = ext2_get_parent,
415 };
416 
417 static unsigned long get_sb_block(void **data)
418 {
419 	unsigned long 	sb_block;
420 	char 		*options = (char *) *data;
421 
422 	if (!options || strncmp(options, "sb=", 3) != 0)
423 		return 1;	/* Default location */
424 	options += 3;
425 	sb_block = simple_strtoul(options, &options, 0);
426 	if (*options && *options != ',') {
427 		printk("EXT2-fs: Invalid sb specification: %s\n",
428 		       (char *) *data);
429 		return 1;
430 	}
431 	if (*options == ',')
432 		options++;
433 	*data = (void *) options;
434 	return sb_block;
435 }
436 
437 enum {
438 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
439 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
440 	Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
441 	Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
442 	Opt_acl, Opt_noacl, Opt_xip, Opt_dax, Opt_ignore, Opt_err, Opt_quota,
443 	Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
444 };
445 
446 static const match_table_t tokens = {
447 	{Opt_bsd_df, "bsddf"},
448 	{Opt_minix_df, "minixdf"},
449 	{Opt_grpid, "grpid"},
450 	{Opt_grpid, "bsdgroups"},
451 	{Opt_nogrpid, "nogrpid"},
452 	{Opt_nogrpid, "sysvgroups"},
453 	{Opt_resgid, "resgid=%u"},
454 	{Opt_resuid, "resuid=%u"},
455 	{Opt_sb, "sb=%u"},
456 	{Opt_err_cont, "errors=continue"},
457 	{Opt_err_panic, "errors=panic"},
458 	{Opt_err_ro, "errors=remount-ro"},
459 	{Opt_nouid32, "nouid32"},
460 	{Opt_nocheck, "check=none"},
461 	{Opt_nocheck, "nocheck"},
462 	{Opt_debug, "debug"},
463 	{Opt_oldalloc, "oldalloc"},
464 	{Opt_orlov, "orlov"},
465 	{Opt_nobh, "nobh"},
466 	{Opt_user_xattr, "user_xattr"},
467 	{Opt_nouser_xattr, "nouser_xattr"},
468 	{Opt_acl, "acl"},
469 	{Opt_noacl, "noacl"},
470 	{Opt_xip, "xip"},
471 	{Opt_dax, "dax"},
472 	{Opt_grpquota, "grpquota"},
473 	{Opt_ignore, "noquota"},
474 	{Opt_quota, "quota"},
475 	{Opt_usrquota, "usrquota"},
476 	{Opt_reservation, "reservation"},
477 	{Opt_noreservation, "noreservation"},
478 	{Opt_err, NULL}
479 };
480 
481 static int parse_options(char *options, struct super_block *sb,
482 			 struct ext2_mount_options *opts)
483 {
484 	char *p;
485 	substring_t args[MAX_OPT_ARGS];
486 	int option;
487 	kuid_t uid;
488 	kgid_t gid;
489 
490 	if (!options)
491 		return 1;
492 
493 	while ((p = strsep (&options, ",")) != NULL) {
494 		int token;
495 		if (!*p)
496 			continue;
497 
498 		token = match_token(p, tokens, args);
499 		switch (token) {
500 		case Opt_bsd_df:
501 			clear_opt (opts->s_mount_opt, MINIX_DF);
502 			break;
503 		case Opt_minix_df:
504 			set_opt (opts->s_mount_opt, MINIX_DF);
505 			break;
506 		case Opt_grpid:
507 			set_opt (opts->s_mount_opt, GRPID);
508 			break;
509 		case Opt_nogrpid:
510 			clear_opt (opts->s_mount_opt, GRPID);
511 			break;
512 		case Opt_resuid:
513 			if (match_int(&args[0], &option))
514 				return 0;
515 			uid = make_kuid(current_user_ns(), option);
516 			if (!uid_valid(uid)) {
517 				ext2_msg(sb, KERN_ERR, "Invalid uid value %d", option);
518 				return 0;
519 
520 			}
521 			opts->s_resuid = uid;
522 			break;
523 		case Opt_resgid:
524 			if (match_int(&args[0], &option))
525 				return 0;
526 			gid = make_kgid(current_user_ns(), option);
527 			if (!gid_valid(gid)) {
528 				ext2_msg(sb, KERN_ERR, "Invalid gid value %d", option);
529 				return 0;
530 			}
531 			opts->s_resgid = gid;
532 			break;
533 		case Opt_sb:
534 			/* handled by get_sb_block() instead of here */
535 			/* *sb_block = match_int(&args[0]); */
536 			break;
537 		case Opt_err_panic:
538 			clear_opt (opts->s_mount_opt, ERRORS_CONT);
539 			clear_opt (opts->s_mount_opt, ERRORS_RO);
540 			set_opt (opts->s_mount_opt, ERRORS_PANIC);
541 			break;
542 		case Opt_err_ro:
543 			clear_opt (opts->s_mount_opt, ERRORS_CONT);
544 			clear_opt (opts->s_mount_opt, ERRORS_PANIC);
545 			set_opt (opts->s_mount_opt, ERRORS_RO);
546 			break;
547 		case Opt_err_cont:
548 			clear_opt (opts->s_mount_opt, ERRORS_RO);
549 			clear_opt (opts->s_mount_opt, ERRORS_PANIC);
550 			set_opt (opts->s_mount_opt, ERRORS_CONT);
551 			break;
552 		case Opt_nouid32:
553 			set_opt (opts->s_mount_opt, NO_UID32);
554 			break;
555 		case Opt_nocheck:
556 			ext2_msg(sb, KERN_WARNING,
557 				"Option nocheck/check=none is deprecated and"
558 				" will be removed in June 2020.");
559 			clear_opt (opts->s_mount_opt, CHECK);
560 			break;
561 		case Opt_debug:
562 			set_opt (opts->s_mount_opt, DEBUG);
563 			break;
564 		case Opt_oldalloc:
565 			set_opt (opts->s_mount_opt, OLDALLOC);
566 			break;
567 		case Opt_orlov:
568 			clear_opt (opts->s_mount_opt, OLDALLOC);
569 			break;
570 		case Opt_nobh:
571 			set_opt (opts->s_mount_opt, NOBH);
572 			break;
573 #ifdef CONFIG_EXT2_FS_XATTR
574 		case Opt_user_xattr:
575 			set_opt (opts->s_mount_opt, XATTR_USER);
576 			break;
577 		case Opt_nouser_xattr:
578 			clear_opt (opts->s_mount_opt, XATTR_USER);
579 			break;
580 #else
581 		case Opt_user_xattr:
582 		case Opt_nouser_xattr:
583 			ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
584 				"not supported");
585 			break;
586 #endif
587 #ifdef CONFIG_EXT2_FS_POSIX_ACL
588 		case Opt_acl:
589 			set_opt(opts->s_mount_opt, POSIX_ACL);
590 			break;
591 		case Opt_noacl:
592 			clear_opt(opts->s_mount_opt, POSIX_ACL);
593 			break;
594 #else
595 		case Opt_acl:
596 		case Opt_noacl:
597 			ext2_msg(sb, KERN_INFO,
598 				"(no)acl options not supported");
599 			break;
600 #endif
601 		case Opt_xip:
602 			ext2_msg(sb, KERN_INFO, "use dax instead of xip");
603 			set_opt(opts->s_mount_opt, XIP);
604 			/* Fall through */
605 		case Opt_dax:
606 #ifdef CONFIG_FS_DAX
607 			ext2_msg(sb, KERN_WARNING,
608 		"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
609 			set_opt(opts->s_mount_opt, DAX);
610 #else
611 			ext2_msg(sb, KERN_INFO, "dax option not supported");
612 #endif
613 			break;
614 
615 #if defined(CONFIG_QUOTA)
616 		case Opt_quota:
617 		case Opt_usrquota:
618 			set_opt(opts->s_mount_opt, USRQUOTA);
619 			break;
620 
621 		case Opt_grpquota:
622 			set_opt(opts->s_mount_opt, GRPQUOTA);
623 			break;
624 #else
625 		case Opt_quota:
626 		case Opt_usrquota:
627 		case Opt_grpquota:
628 			ext2_msg(sb, KERN_INFO,
629 				"quota operations not supported");
630 			break;
631 #endif
632 
633 		case Opt_reservation:
634 			set_opt(opts->s_mount_opt, RESERVATION);
635 			ext2_msg(sb, KERN_INFO, "reservations ON");
636 			break;
637 		case Opt_noreservation:
638 			clear_opt(opts->s_mount_opt, RESERVATION);
639 			ext2_msg(sb, KERN_INFO, "reservations OFF");
640 			break;
641 		case Opt_ignore:
642 			break;
643 		default:
644 			return 0;
645 		}
646 	}
647 	return 1;
648 }
649 
650 static int ext2_setup_super (struct super_block * sb,
651 			      struct ext2_super_block * es,
652 			      int read_only)
653 {
654 	int res = 0;
655 	struct ext2_sb_info *sbi = EXT2_SB(sb);
656 
657 	if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
658 		ext2_msg(sb, KERN_ERR,
659 			"error: revision level too high, "
660 			"forcing read-only mode");
661 		res = SB_RDONLY;
662 	}
663 	if (read_only)
664 		return res;
665 	if (!(sbi->s_mount_state & EXT2_VALID_FS))
666 		ext2_msg(sb, KERN_WARNING,
667 			"warning: mounting unchecked fs, "
668 			"running e2fsck is recommended");
669 	else if ((sbi->s_mount_state & EXT2_ERROR_FS))
670 		ext2_msg(sb, KERN_WARNING,
671 			"warning: mounting fs with errors, "
672 			"running e2fsck is recommended");
673 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
674 		 le16_to_cpu(es->s_mnt_count) >=
675 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
676 		ext2_msg(sb, KERN_WARNING,
677 			"warning: maximal mount count reached, "
678 			"running e2fsck is recommended");
679 	else if (le32_to_cpu(es->s_checkinterval) &&
680 		(le32_to_cpu(es->s_lastcheck) +
681 			le32_to_cpu(es->s_checkinterval) <=
682 			ktime_get_real_seconds()))
683 		ext2_msg(sb, KERN_WARNING,
684 			"warning: checktime reached, "
685 			"running e2fsck is recommended");
686 	if (!le16_to_cpu(es->s_max_mnt_count))
687 		es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
688 	le16_add_cpu(&es->s_mnt_count, 1);
689 	if (test_opt (sb, DEBUG))
690 		ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
691 			"bpg=%lu, ipg=%lu, mo=%04lx]",
692 			EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
693 			sbi->s_frag_size,
694 			sbi->s_groups_count,
695 			EXT2_BLOCKS_PER_GROUP(sb),
696 			EXT2_INODES_PER_GROUP(sb),
697 			sbi->s_mount_opt);
698 	return res;
699 }
700 
701 static int ext2_check_descriptors(struct super_block *sb)
702 {
703 	int i;
704 	struct ext2_sb_info *sbi = EXT2_SB(sb);
705 
706 	ext2_debug ("Checking group descriptors");
707 
708 	for (i = 0; i < sbi->s_groups_count; i++) {
709 		struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
710 		ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
711 		ext2_fsblk_t last_block;
712 
713 		if (i == sbi->s_groups_count - 1)
714 			last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
715 		else
716 			last_block = first_block +
717 				(EXT2_BLOCKS_PER_GROUP(sb) - 1);
718 
719 		if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
720 		    le32_to_cpu(gdp->bg_block_bitmap) > last_block)
721 		{
722 			ext2_error (sb, "ext2_check_descriptors",
723 				    "Block bitmap for group %d"
724 				    " not in group (block %lu)!",
725 				    i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
726 			return 0;
727 		}
728 		if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
729 		    le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
730 		{
731 			ext2_error (sb, "ext2_check_descriptors",
732 				    "Inode bitmap for group %d"
733 				    " not in group (block %lu)!",
734 				    i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
735 			return 0;
736 		}
737 		if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
738 		    le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
739 		    last_block)
740 		{
741 			ext2_error (sb, "ext2_check_descriptors",
742 				    "Inode table for group %d"
743 				    " not in group (block %lu)!",
744 				    i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
745 			return 0;
746 		}
747 	}
748 	return 1;
749 }
750 
751 /*
752  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
753  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
754  * We need to be 1 filesystem block less than the 2^32 sector limit.
755  */
756 static loff_t ext2_max_size(int bits)
757 {
758 	loff_t res = EXT2_NDIR_BLOCKS;
759 	int meta_blocks;
760 	loff_t upper_limit;
761 
762 	/* This is calculated to be the largest file size for a
763 	 * dense, file such that the total number of
764 	 * sectors in the file, including data and all indirect blocks,
765 	 * does not exceed 2^32 -1
766 	 * __u32 i_blocks representing the total number of
767 	 * 512 bytes blocks of the file
768 	 */
769 	upper_limit = (1LL << 32) - 1;
770 
771 	/* total blocks in file system block size */
772 	upper_limit >>= (bits - 9);
773 
774 
775 	/* indirect blocks */
776 	meta_blocks = 1;
777 	/* double indirect blocks */
778 	meta_blocks += 1 + (1LL << (bits-2));
779 	/* tripple indirect blocks */
780 	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
781 
782 	upper_limit -= meta_blocks;
783 	upper_limit <<= bits;
784 
785 	res += 1LL << (bits-2);
786 	res += 1LL << (2*(bits-2));
787 	res += 1LL << (3*(bits-2));
788 	res <<= bits;
789 	if (res > upper_limit)
790 		res = upper_limit;
791 
792 	if (res > MAX_LFS_FILESIZE)
793 		res = MAX_LFS_FILESIZE;
794 
795 	return res;
796 }
797 
798 static unsigned long descriptor_loc(struct super_block *sb,
799 				    unsigned long logic_sb_block,
800 				    int nr)
801 {
802 	struct ext2_sb_info *sbi = EXT2_SB(sb);
803 	unsigned long bg, first_meta_bg;
804 	int has_super = 0;
805 
806 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
807 
808 	if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
809 	    nr < first_meta_bg)
810 		return (logic_sb_block + nr + 1);
811 	bg = sbi->s_desc_per_block * nr;
812 	if (ext2_bg_has_super(sb, bg))
813 		has_super = 1;
814 
815 	return ext2_group_first_block_no(sb, bg) + has_super;
816 }
817 
818 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
819 {
820 	struct dax_device *dax_dev = fs_dax_get_by_bdev(sb->s_bdev);
821 	struct buffer_head * bh;
822 	struct ext2_sb_info * sbi;
823 	struct ext2_super_block * es;
824 	struct inode *root;
825 	unsigned long block;
826 	unsigned long sb_block = get_sb_block(&data);
827 	unsigned long logic_sb_block;
828 	unsigned long offset = 0;
829 	unsigned long def_mount_opts;
830 	long ret = -ENOMEM;
831 	int blocksize = BLOCK_SIZE;
832 	int db_count;
833 	int i, j;
834 	__le32 features;
835 	int err;
836 	struct ext2_mount_options opts;
837 
838 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
839 	if (!sbi)
840 		goto failed;
841 
842 	sbi->s_blockgroup_lock =
843 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
844 	if (!sbi->s_blockgroup_lock) {
845 		kfree(sbi);
846 		goto failed;
847 	}
848 	sb->s_fs_info = sbi;
849 	sbi->s_sb_block = sb_block;
850 	sbi->s_daxdev = dax_dev;
851 
852 	spin_lock_init(&sbi->s_lock);
853 	ret = -EINVAL;
854 
855 	/*
856 	 * See what the current blocksize for the device is, and
857 	 * use that as the blocksize.  Otherwise (or if the blocksize
858 	 * is smaller than the default) use the default.
859 	 * This is important for devices that have a hardware
860 	 * sectorsize that is larger than the default.
861 	 */
862 	blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
863 	if (!blocksize) {
864 		ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
865 		goto failed_sbi;
866 	}
867 
868 	/*
869 	 * If the superblock doesn't start on a hardware sector boundary,
870 	 * calculate the offset.
871 	 */
872 	if (blocksize != BLOCK_SIZE) {
873 		logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
874 		offset = (sb_block*BLOCK_SIZE) % blocksize;
875 	} else {
876 		logic_sb_block = sb_block;
877 	}
878 
879 	if (!(bh = sb_bread(sb, logic_sb_block))) {
880 		ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
881 		goto failed_sbi;
882 	}
883 	/*
884 	 * Note: s_es must be initialized as soon as possible because
885 	 *       some ext2 macro-instructions depend on its value
886 	 */
887 	es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
888 	sbi->s_es = es;
889 	sb->s_magic = le16_to_cpu(es->s_magic);
890 
891 	if (sb->s_magic != EXT2_SUPER_MAGIC)
892 		goto cantfind_ext2;
893 
894 	opts.s_mount_opt = 0;
895 	/* Set defaults before we parse the mount options */
896 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
897 	if (def_mount_opts & EXT2_DEFM_DEBUG)
898 		set_opt(opts.s_mount_opt, DEBUG);
899 	if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
900 		set_opt(opts.s_mount_opt, GRPID);
901 	if (def_mount_opts & EXT2_DEFM_UID16)
902 		set_opt(opts.s_mount_opt, NO_UID32);
903 #ifdef CONFIG_EXT2_FS_XATTR
904 	if (def_mount_opts & EXT2_DEFM_XATTR_USER)
905 		set_opt(opts.s_mount_opt, XATTR_USER);
906 #endif
907 #ifdef CONFIG_EXT2_FS_POSIX_ACL
908 	if (def_mount_opts & EXT2_DEFM_ACL)
909 		set_opt(opts.s_mount_opt, POSIX_ACL);
910 #endif
911 
912 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
913 		set_opt(opts.s_mount_opt, ERRORS_PANIC);
914 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
915 		set_opt(opts.s_mount_opt, ERRORS_CONT);
916 	else
917 		set_opt(opts.s_mount_opt, ERRORS_RO);
918 
919 	opts.s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
920 	opts.s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
921 
922 	set_opt(opts.s_mount_opt, RESERVATION);
923 
924 	if (!parse_options((char *) data, sb, &opts))
925 		goto failed_mount;
926 
927 	sbi->s_mount_opt = opts.s_mount_opt;
928 	sbi->s_resuid = opts.s_resuid;
929 	sbi->s_resgid = opts.s_resgid;
930 
931 	sb->s_flags = (sb->s_flags & ~SB_POSIXACL) |
932 		((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
933 		 SB_POSIXACL : 0);
934 	sb->s_iflags |= SB_I_CGROUPWB;
935 
936 	if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
937 	    (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
938 	     EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
939 	     EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
940 		ext2_msg(sb, KERN_WARNING,
941 			"warning: feature flags set on rev 0 fs, "
942 			"running e2fsck is recommended");
943 	/*
944 	 * Check feature flags regardless of the revision level, since we
945 	 * previously didn't change the revision level when setting the flags,
946 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
947 	 */
948 	features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
949 	if (features) {
950 		ext2_msg(sb, KERN_ERR,	"error: couldn't mount because of "
951 		       "unsupported optional features (%x)",
952 			le32_to_cpu(features));
953 		goto failed_mount;
954 	}
955 	if (!sb_rdonly(sb) && (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
956 		ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
957 		       "unsupported optional features (%x)",
958 		       le32_to_cpu(features));
959 		goto failed_mount;
960 	}
961 
962 	blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
963 
964 	if (sbi->s_mount_opt & EXT2_MOUNT_DAX) {
965 		if (!bdev_dax_supported(sb->s_bdev, blocksize)) {
966 			ext2_msg(sb, KERN_ERR,
967 				"DAX unsupported by block device. Turning off DAX.");
968 			sbi->s_mount_opt &= ~EXT2_MOUNT_DAX;
969 		}
970 	}
971 
972 	/* If the blocksize doesn't match, re-read the thing.. */
973 	if (sb->s_blocksize != blocksize) {
974 		brelse(bh);
975 
976 		if (!sb_set_blocksize(sb, blocksize)) {
977 			ext2_msg(sb, KERN_ERR,
978 				"error: bad blocksize %d", blocksize);
979 			goto failed_sbi;
980 		}
981 
982 		logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
983 		offset = (sb_block*BLOCK_SIZE) % blocksize;
984 		bh = sb_bread(sb, logic_sb_block);
985 		if(!bh) {
986 			ext2_msg(sb, KERN_ERR, "error: couldn't read"
987 				"superblock on 2nd try");
988 			goto failed_sbi;
989 		}
990 		es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
991 		sbi->s_es = es;
992 		if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
993 			ext2_msg(sb, KERN_ERR, "error: magic mismatch");
994 			goto failed_mount;
995 		}
996 	}
997 
998 	sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
999 	sb->s_max_links = EXT2_LINK_MAX;
1000 
1001 	if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
1002 		sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
1003 		sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
1004 	} else {
1005 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
1006 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
1007 		if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
1008 		    !is_power_of_2(sbi->s_inode_size) ||
1009 		    (sbi->s_inode_size > blocksize)) {
1010 			ext2_msg(sb, KERN_ERR,
1011 				"error: unsupported inode size: %d",
1012 				sbi->s_inode_size);
1013 			goto failed_mount;
1014 		}
1015 	}
1016 
1017 	sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
1018 				   le32_to_cpu(es->s_log_frag_size);
1019 	if (sbi->s_frag_size == 0)
1020 		goto cantfind_ext2;
1021 	sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
1022 
1023 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
1024 	sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
1025 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
1026 
1027 	if (EXT2_INODE_SIZE(sb) == 0)
1028 		goto cantfind_ext2;
1029 	sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
1030 	if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
1031 		goto cantfind_ext2;
1032 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
1033 					sbi->s_inodes_per_block;
1034 	sbi->s_desc_per_block = sb->s_blocksize /
1035 					sizeof (struct ext2_group_desc);
1036 	sbi->s_sbh = bh;
1037 	sbi->s_mount_state = le16_to_cpu(es->s_state);
1038 	sbi->s_addr_per_block_bits =
1039 		ilog2 (EXT2_ADDR_PER_BLOCK(sb));
1040 	sbi->s_desc_per_block_bits =
1041 		ilog2 (EXT2_DESC_PER_BLOCK(sb));
1042 
1043 	if (sb->s_magic != EXT2_SUPER_MAGIC)
1044 		goto cantfind_ext2;
1045 
1046 	if (sb->s_blocksize != bh->b_size) {
1047 		if (!silent)
1048 			ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
1049 		goto failed_mount;
1050 	}
1051 
1052 	if (sb->s_blocksize != sbi->s_frag_size) {
1053 		ext2_msg(sb, KERN_ERR,
1054 			"error: fragsize %lu != blocksize %lu"
1055 			"(not supported yet)",
1056 			sbi->s_frag_size, sb->s_blocksize);
1057 		goto failed_mount;
1058 	}
1059 
1060 	if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
1061 		ext2_msg(sb, KERN_ERR,
1062 			"error: #blocks per group too big: %lu",
1063 			sbi->s_blocks_per_group);
1064 		goto failed_mount;
1065 	}
1066 	if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
1067 		ext2_msg(sb, KERN_ERR,
1068 			"error: #fragments per group too big: %lu",
1069 			sbi->s_frags_per_group);
1070 		goto failed_mount;
1071 	}
1072 	if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
1073 		ext2_msg(sb, KERN_ERR,
1074 			"error: #inodes per group too big: %lu",
1075 			sbi->s_inodes_per_group);
1076 		goto failed_mount;
1077 	}
1078 
1079 	if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
1080 		goto cantfind_ext2;
1081  	sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
1082  				le32_to_cpu(es->s_first_data_block) - 1)
1083  					/ EXT2_BLOCKS_PER_GROUP(sb)) + 1;
1084 	db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
1085 		   EXT2_DESC_PER_BLOCK(sb);
1086 	sbi->s_group_desc = kmalloc_array (db_count,
1087 					   sizeof(struct buffer_head *),
1088 					   GFP_KERNEL);
1089 	if (sbi->s_group_desc == NULL) {
1090 		ext2_msg(sb, KERN_ERR, "error: not enough memory");
1091 		goto failed_mount;
1092 	}
1093 	bgl_lock_init(sbi->s_blockgroup_lock);
1094 	sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1095 	if (!sbi->s_debts) {
1096 		ext2_msg(sb, KERN_ERR, "error: not enough memory");
1097 		goto failed_mount_group_desc;
1098 	}
1099 	for (i = 0; i < db_count; i++) {
1100 		block = descriptor_loc(sb, logic_sb_block, i);
1101 		sbi->s_group_desc[i] = sb_bread(sb, block);
1102 		if (!sbi->s_group_desc[i]) {
1103 			for (j = 0; j < i; j++)
1104 				brelse (sbi->s_group_desc[j]);
1105 			ext2_msg(sb, KERN_ERR,
1106 				"error: unable to read group descriptors");
1107 			goto failed_mount_group_desc;
1108 		}
1109 	}
1110 	if (!ext2_check_descriptors (sb)) {
1111 		ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1112 		goto failed_mount2;
1113 	}
1114 	sbi->s_gdb_count = db_count;
1115 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1116 	spin_lock_init(&sbi->s_next_gen_lock);
1117 
1118 	/* per fileystem reservation list head & lock */
1119 	spin_lock_init(&sbi->s_rsv_window_lock);
1120 	sbi->s_rsv_window_root = RB_ROOT;
1121 	/*
1122 	 * Add a single, static dummy reservation to the start of the
1123 	 * reservation window list --- it gives us a placeholder for
1124 	 * append-at-start-of-list which makes the allocation logic
1125 	 * _much_ simpler.
1126 	 */
1127 	sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1128 	sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1129 	sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1130 	sbi->s_rsv_window_head.rsv_goal_size = 0;
1131 	ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1132 
1133 	err = percpu_counter_init(&sbi->s_freeblocks_counter,
1134 				ext2_count_free_blocks(sb), GFP_KERNEL);
1135 	if (!err) {
1136 		err = percpu_counter_init(&sbi->s_freeinodes_counter,
1137 				ext2_count_free_inodes(sb), GFP_KERNEL);
1138 	}
1139 	if (!err) {
1140 		err = percpu_counter_init(&sbi->s_dirs_counter,
1141 				ext2_count_dirs(sb), GFP_KERNEL);
1142 	}
1143 	if (err) {
1144 		ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1145 		goto failed_mount3;
1146 	}
1147 
1148 #ifdef CONFIG_EXT2_FS_XATTR
1149 	sbi->s_ea_block_cache = ext2_xattr_create_cache();
1150 	if (!sbi->s_ea_block_cache) {
1151 		ext2_msg(sb, KERN_ERR, "Failed to create ea_block_cache");
1152 		goto failed_mount3;
1153 	}
1154 #endif
1155 	/*
1156 	 * set up enough so that it can read an inode
1157 	 */
1158 	sb->s_op = &ext2_sops;
1159 	sb->s_export_op = &ext2_export_ops;
1160 	sb->s_xattr = ext2_xattr_handlers;
1161 
1162 #ifdef CONFIG_QUOTA
1163 	sb->dq_op = &dquot_operations;
1164 	sb->s_qcop = &ext2_quotactl_ops;
1165 	sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP;
1166 #endif
1167 
1168 	root = ext2_iget(sb, EXT2_ROOT_INO);
1169 	if (IS_ERR(root)) {
1170 		ret = PTR_ERR(root);
1171 		goto failed_mount3;
1172 	}
1173 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1174 		iput(root);
1175 		ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1176 		goto failed_mount3;
1177 	}
1178 
1179 	sb->s_root = d_make_root(root);
1180 	if (!sb->s_root) {
1181 		ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1182 		ret = -ENOMEM;
1183 		goto failed_mount3;
1184 	}
1185 	if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1186 		ext2_msg(sb, KERN_WARNING,
1187 			"warning: mounting ext3 filesystem as ext2");
1188 	if (ext2_setup_super (sb, es, sb_rdonly(sb)))
1189 		sb->s_flags |= SB_RDONLY;
1190 	ext2_write_super(sb);
1191 	return 0;
1192 
1193 cantfind_ext2:
1194 	if (!silent)
1195 		ext2_msg(sb, KERN_ERR,
1196 			"error: can't find an ext2 filesystem on dev %s.",
1197 			sb->s_id);
1198 	goto failed_mount;
1199 failed_mount3:
1200 	ext2_xattr_destroy_cache(sbi->s_ea_block_cache);
1201 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
1202 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
1203 	percpu_counter_destroy(&sbi->s_dirs_counter);
1204 failed_mount2:
1205 	for (i = 0; i < db_count; i++)
1206 		brelse(sbi->s_group_desc[i]);
1207 failed_mount_group_desc:
1208 	kfree(sbi->s_group_desc);
1209 	kfree(sbi->s_debts);
1210 failed_mount:
1211 	brelse(bh);
1212 failed_sbi:
1213 	sb->s_fs_info = NULL;
1214 	kfree(sbi->s_blockgroup_lock);
1215 	kfree(sbi);
1216 failed:
1217 	fs_put_dax(dax_dev);
1218 	return ret;
1219 }
1220 
1221 static void ext2_clear_super_error(struct super_block *sb)
1222 {
1223 	struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1224 
1225 	if (buffer_write_io_error(sbh)) {
1226 		/*
1227 		 * Oh, dear.  A previous attempt to write the
1228 		 * superblock failed.  This could happen because the
1229 		 * USB device was yanked out.  Or it could happen to
1230 		 * be a transient write error and maybe the block will
1231 		 * be remapped.  Nothing we can do but to retry the
1232 		 * write and hope for the best.
1233 		 */
1234 		ext2_msg(sb, KERN_ERR,
1235 		       "previous I/O error to superblock detected");
1236 		clear_buffer_write_io_error(sbh);
1237 		set_buffer_uptodate(sbh);
1238 	}
1239 }
1240 
1241 void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1242 		     int wait)
1243 {
1244 	ext2_clear_super_error(sb);
1245 	spin_lock(&EXT2_SB(sb)->s_lock);
1246 	es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1247 	es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1248 	es->s_wtime = cpu_to_le32(ktime_get_real_seconds());
1249 	/* unlock before we do IO */
1250 	spin_unlock(&EXT2_SB(sb)->s_lock);
1251 	mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1252 	if (wait)
1253 		sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1254 }
1255 
1256 /*
1257  * In the second extended file system, it is not necessary to
1258  * write the super block since we use a mapping of the
1259  * disk super block in a buffer.
1260  *
1261  * However, this function is still used to set the fs valid
1262  * flags to 0.  We need to set this flag to 0 since the fs
1263  * may have been checked while mounted and e2fsck may have
1264  * set s_state to EXT2_VALID_FS after some corrections.
1265  */
1266 static int ext2_sync_fs(struct super_block *sb, int wait)
1267 {
1268 	struct ext2_sb_info *sbi = EXT2_SB(sb);
1269 	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1270 
1271 	/*
1272 	 * Write quota structures to quota file, sync_blockdev() will write
1273 	 * them to disk later
1274 	 */
1275 	dquot_writeback_dquots(sb, -1);
1276 
1277 	spin_lock(&sbi->s_lock);
1278 	if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1279 		ext2_debug("setting valid to 0\n");
1280 		es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1281 	}
1282 	spin_unlock(&sbi->s_lock);
1283 	ext2_sync_super(sb, es, wait);
1284 	return 0;
1285 }
1286 
1287 static int ext2_freeze(struct super_block *sb)
1288 {
1289 	struct ext2_sb_info *sbi = EXT2_SB(sb);
1290 
1291 	/*
1292 	 * Open but unlinked files present? Keep EXT2_VALID_FS flag cleared
1293 	 * because we have unattached inodes and thus filesystem is not fully
1294 	 * consistent.
1295 	 */
1296 	if (atomic_long_read(&sb->s_remove_count)) {
1297 		ext2_sync_fs(sb, 1);
1298 		return 0;
1299 	}
1300 	/* Set EXT2_FS_VALID flag */
1301 	spin_lock(&sbi->s_lock);
1302 	sbi->s_es->s_state = cpu_to_le16(sbi->s_mount_state);
1303 	spin_unlock(&sbi->s_lock);
1304 	ext2_sync_super(sb, sbi->s_es, 1);
1305 
1306 	return 0;
1307 }
1308 
1309 static int ext2_unfreeze(struct super_block *sb)
1310 {
1311 	/* Just write sb to clear EXT2_VALID_FS flag */
1312 	ext2_write_super(sb);
1313 
1314 	return 0;
1315 }
1316 
1317 static void ext2_write_super(struct super_block *sb)
1318 {
1319 	if (!sb_rdonly(sb))
1320 		ext2_sync_fs(sb, 1);
1321 }
1322 
1323 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1324 {
1325 	struct ext2_sb_info * sbi = EXT2_SB(sb);
1326 	struct ext2_super_block * es;
1327 	struct ext2_mount_options new_opts;
1328 	int err;
1329 
1330 	sync_filesystem(sb);
1331 
1332 	spin_lock(&sbi->s_lock);
1333 	new_opts.s_mount_opt = sbi->s_mount_opt;
1334 	new_opts.s_resuid = sbi->s_resuid;
1335 	new_opts.s_resgid = sbi->s_resgid;
1336 	spin_unlock(&sbi->s_lock);
1337 
1338 	if (!parse_options(data, sb, &new_opts))
1339 		return -EINVAL;
1340 
1341 	spin_lock(&sbi->s_lock);
1342 	es = sbi->s_es;
1343 	if ((sbi->s_mount_opt ^ new_opts.s_mount_opt) & EXT2_MOUNT_DAX) {
1344 		ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1345 			 "dax flag with busy inodes while remounting");
1346 		new_opts.s_mount_opt ^= EXT2_MOUNT_DAX;
1347 	}
1348 	if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1349 		goto out_set;
1350 	if (*flags & SB_RDONLY) {
1351 		if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1352 		    !(sbi->s_mount_state & EXT2_VALID_FS))
1353 			goto out_set;
1354 
1355 		/*
1356 		 * OK, we are remounting a valid rw partition rdonly, so set
1357 		 * the rdonly flag and then mark the partition as valid again.
1358 		 */
1359 		es->s_state = cpu_to_le16(sbi->s_mount_state);
1360 		es->s_mtime = cpu_to_le32(ktime_get_real_seconds());
1361 		spin_unlock(&sbi->s_lock);
1362 
1363 		err = dquot_suspend(sb, -1);
1364 		if (err < 0)
1365 			return err;
1366 
1367 		ext2_sync_super(sb, es, 1);
1368 	} else {
1369 		__le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1370 					       ~EXT2_FEATURE_RO_COMPAT_SUPP);
1371 		if (ret) {
1372 			spin_unlock(&sbi->s_lock);
1373 			ext2_msg(sb, KERN_WARNING,
1374 				"warning: couldn't remount RDWR because of "
1375 				"unsupported optional features (%x).",
1376 				le32_to_cpu(ret));
1377 			return -EROFS;
1378 		}
1379 		/*
1380 		 * Mounting a RDONLY partition read-write, so reread and
1381 		 * store the current valid flag.  (It may have been changed
1382 		 * by e2fsck since we originally mounted the partition.)
1383 		 */
1384 		sbi->s_mount_state = le16_to_cpu(es->s_state);
1385 		if (!ext2_setup_super (sb, es, 0))
1386 			sb->s_flags &= ~SB_RDONLY;
1387 		spin_unlock(&sbi->s_lock);
1388 
1389 		ext2_write_super(sb);
1390 
1391 		dquot_resume(sb, -1);
1392 	}
1393 
1394 	spin_lock(&sbi->s_lock);
1395 out_set:
1396 	sbi->s_mount_opt = new_opts.s_mount_opt;
1397 	sbi->s_resuid = new_opts.s_resuid;
1398 	sbi->s_resgid = new_opts.s_resgid;
1399 	sb->s_flags = (sb->s_flags & ~SB_POSIXACL) |
1400 		((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? SB_POSIXACL : 0);
1401 	spin_unlock(&sbi->s_lock);
1402 
1403 	return 0;
1404 }
1405 
1406 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1407 {
1408 	struct super_block *sb = dentry->d_sb;
1409 	struct ext2_sb_info *sbi = EXT2_SB(sb);
1410 	struct ext2_super_block *es = sbi->s_es;
1411 	u64 fsid;
1412 
1413 	spin_lock(&sbi->s_lock);
1414 
1415 	if (test_opt (sb, MINIX_DF))
1416 		sbi->s_overhead_last = 0;
1417 	else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1418 		unsigned long i, overhead = 0;
1419 		smp_rmb();
1420 
1421 		/*
1422 		 * Compute the overhead (FS structures). This is constant
1423 		 * for a given filesystem unless the number of block groups
1424 		 * changes so we cache the previous value until it does.
1425 		 */
1426 
1427 		/*
1428 		 * All of the blocks before first_data_block are
1429 		 * overhead
1430 		 */
1431 		overhead = le32_to_cpu(es->s_first_data_block);
1432 
1433 		/*
1434 		 * Add the overhead attributed to the superblock and
1435 		 * block group descriptors.  If the sparse superblocks
1436 		 * feature is turned on, then not all groups have this.
1437 		 */
1438 		for (i = 0; i < sbi->s_groups_count; i++)
1439 			overhead += ext2_bg_has_super(sb, i) +
1440 				ext2_bg_num_gdb(sb, i);
1441 
1442 		/*
1443 		 * Every block group has an inode bitmap, a block
1444 		 * bitmap, and an inode table.
1445 		 */
1446 		overhead += (sbi->s_groups_count *
1447 			     (2 + sbi->s_itb_per_group));
1448 		sbi->s_overhead_last = overhead;
1449 		smp_wmb();
1450 		sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1451 	}
1452 
1453 	buf->f_type = EXT2_SUPER_MAGIC;
1454 	buf->f_bsize = sb->s_blocksize;
1455 	buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1456 	buf->f_bfree = ext2_count_free_blocks(sb);
1457 	es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1458 	buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1459 	if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1460 		buf->f_bavail = 0;
1461 	buf->f_files = le32_to_cpu(es->s_inodes_count);
1462 	buf->f_ffree = ext2_count_free_inodes(sb);
1463 	es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1464 	buf->f_namelen = EXT2_NAME_LEN;
1465 	fsid = le64_to_cpup((void *)es->s_uuid) ^
1466 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1467 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1468 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1469 	spin_unlock(&sbi->s_lock);
1470 	return 0;
1471 }
1472 
1473 static struct dentry *ext2_mount(struct file_system_type *fs_type,
1474 	int flags, const char *dev_name, void *data)
1475 {
1476 	return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1477 }
1478 
1479 #ifdef CONFIG_QUOTA
1480 
1481 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1482  * acquiring the locks... As quota files are never truncated and quota code
1483  * itself serializes the operations (and no one else should touch the files)
1484  * we don't have to be afraid of races */
1485 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1486 			       size_t len, loff_t off)
1487 {
1488 	struct inode *inode = sb_dqopt(sb)->files[type];
1489 	sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1490 	int err = 0;
1491 	int offset = off & (sb->s_blocksize - 1);
1492 	int tocopy;
1493 	size_t toread;
1494 	struct buffer_head tmp_bh;
1495 	struct buffer_head *bh;
1496 	loff_t i_size = i_size_read(inode);
1497 
1498 	if (off > i_size)
1499 		return 0;
1500 	if (off+len > i_size)
1501 		len = i_size-off;
1502 	toread = len;
1503 	while (toread > 0) {
1504 		tocopy = sb->s_blocksize - offset < toread ?
1505 				sb->s_blocksize - offset : toread;
1506 
1507 		tmp_bh.b_state = 0;
1508 		tmp_bh.b_size = sb->s_blocksize;
1509 		err = ext2_get_block(inode, blk, &tmp_bh, 0);
1510 		if (err < 0)
1511 			return err;
1512 		if (!buffer_mapped(&tmp_bh))	/* A hole? */
1513 			memset(data, 0, tocopy);
1514 		else {
1515 			bh = sb_bread(sb, tmp_bh.b_blocknr);
1516 			if (!bh)
1517 				return -EIO;
1518 			memcpy(data, bh->b_data+offset, tocopy);
1519 			brelse(bh);
1520 		}
1521 		offset = 0;
1522 		toread -= tocopy;
1523 		data += tocopy;
1524 		blk++;
1525 	}
1526 	return len;
1527 }
1528 
1529 /* Write to quotafile */
1530 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1531 				const char *data, size_t len, loff_t off)
1532 {
1533 	struct inode *inode = sb_dqopt(sb)->files[type];
1534 	sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1535 	int err = 0;
1536 	int offset = off & (sb->s_blocksize - 1);
1537 	int tocopy;
1538 	size_t towrite = len;
1539 	struct buffer_head tmp_bh;
1540 	struct buffer_head *bh;
1541 
1542 	while (towrite > 0) {
1543 		tocopy = sb->s_blocksize - offset < towrite ?
1544 				sb->s_blocksize - offset : towrite;
1545 
1546 		tmp_bh.b_state = 0;
1547 		tmp_bh.b_size = sb->s_blocksize;
1548 		err = ext2_get_block(inode, blk, &tmp_bh, 1);
1549 		if (err < 0)
1550 			goto out;
1551 		if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1552 			bh = sb_bread(sb, tmp_bh.b_blocknr);
1553 		else
1554 			bh = sb_getblk(sb, tmp_bh.b_blocknr);
1555 		if (unlikely(!bh)) {
1556 			err = -EIO;
1557 			goto out;
1558 		}
1559 		lock_buffer(bh);
1560 		memcpy(bh->b_data+offset, data, tocopy);
1561 		flush_dcache_page(bh->b_page);
1562 		set_buffer_uptodate(bh);
1563 		mark_buffer_dirty(bh);
1564 		unlock_buffer(bh);
1565 		brelse(bh);
1566 		offset = 0;
1567 		towrite -= tocopy;
1568 		data += tocopy;
1569 		blk++;
1570 	}
1571 out:
1572 	if (len == towrite)
1573 		return err;
1574 	if (inode->i_size < off+len-towrite)
1575 		i_size_write(inode, off+len-towrite);
1576 	inode_inc_iversion(inode);
1577 	inode->i_mtime = inode->i_ctime = current_time(inode);
1578 	mark_inode_dirty(inode);
1579 	return len - towrite;
1580 }
1581 
1582 static int ext2_quota_on(struct super_block *sb, int type, int format_id,
1583 			 const struct path *path)
1584 {
1585 	int err;
1586 	struct inode *inode;
1587 
1588 	err = dquot_quota_on(sb, type, format_id, path);
1589 	if (err)
1590 		return err;
1591 
1592 	inode = d_inode(path->dentry);
1593 	inode_lock(inode);
1594 	EXT2_I(inode)->i_flags |= EXT2_NOATIME_FL | EXT2_IMMUTABLE_FL;
1595 	inode_set_flags(inode, S_NOATIME | S_IMMUTABLE,
1596 			S_NOATIME | S_IMMUTABLE);
1597 	inode_unlock(inode);
1598 	mark_inode_dirty(inode);
1599 
1600 	return 0;
1601 }
1602 
1603 static int ext2_quota_off(struct super_block *sb, int type)
1604 {
1605 	struct inode *inode = sb_dqopt(sb)->files[type];
1606 	int err;
1607 
1608 	if (!inode || !igrab(inode))
1609 		goto out;
1610 
1611 	err = dquot_quota_off(sb, type);
1612 	if (err)
1613 		goto out_put;
1614 
1615 	inode_lock(inode);
1616 	EXT2_I(inode)->i_flags &= ~(EXT2_NOATIME_FL | EXT2_IMMUTABLE_FL);
1617 	inode_set_flags(inode, 0, S_NOATIME | S_IMMUTABLE);
1618 	inode_unlock(inode);
1619 	mark_inode_dirty(inode);
1620 out_put:
1621 	iput(inode);
1622 	return err;
1623 out:
1624 	return dquot_quota_off(sb, type);
1625 }
1626 
1627 #endif
1628 
1629 static struct file_system_type ext2_fs_type = {
1630 	.owner		= THIS_MODULE,
1631 	.name		= "ext2",
1632 	.mount		= ext2_mount,
1633 	.kill_sb	= kill_block_super,
1634 	.fs_flags	= FS_REQUIRES_DEV,
1635 };
1636 MODULE_ALIAS_FS("ext2");
1637 
1638 static int __init init_ext2_fs(void)
1639 {
1640 	int err;
1641 
1642 	err = init_inodecache();
1643 	if (err)
1644 		return err;
1645         err = register_filesystem(&ext2_fs_type);
1646 	if (err)
1647 		goto out;
1648 	return 0;
1649 out:
1650 	destroy_inodecache();
1651 	return err;
1652 }
1653 
1654 static void __exit exit_ext2_fs(void)
1655 {
1656 	unregister_filesystem(&ext2_fs_type);
1657 	destroy_inodecache();
1658 }
1659 
1660 MODULE_AUTHOR("Remy Card and others");
1661 MODULE_DESCRIPTION("Second Extended Filesystem");
1662 MODULE_LICENSE("GPL");
1663 module_init(init_ext2_fs)
1664 module_exit(exit_ext2_fs)
1665