xref: /openbmc/linux/fs/ext2/super.c (revision 2c64e9cb)
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_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 (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
306 		seq_puts(seq, ",usrquota");
307 
308 	if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
309 		seq_puts(seq, ",grpquota");
310 
311 	if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
312 		seq_puts(seq, ",xip");
313 
314 	if (sbi->s_mount_opt & EXT2_MOUNT_DAX)
315 		seq_puts(seq, ",dax");
316 
317 	if (!test_opt(sb, RESERVATION))
318 		seq_puts(seq, ",noreservation");
319 
320 	spin_unlock(&sbi->s_lock);
321 	return 0;
322 }
323 
324 #ifdef CONFIG_QUOTA
325 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
326 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
327 static int ext2_quota_on(struct super_block *sb, int type, int format_id,
328 			 const struct path *path);
329 static struct dquot **ext2_get_dquots(struct inode *inode)
330 {
331 	return EXT2_I(inode)->i_dquot;
332 }
333 
334 static const struct quotactl_ops ext2_quotactl_ops = {
335 	.quota_on	= ext2_quota_on,
336 	.quota_off	= ext2_quota_off,
337 	.quota_sync	= dquot_quota_sync,
338 	.get_state	= dquot_get_state,
339 	.set_info	= dquot_set_dqinfo,
340 	.get_dqblk	= dquot_get_dqblk,
341 	.set_dqblk	= dquot_set_dqblk,
342 	.get_nextdqblk	= dquot_get_next_dqblk,
343 };
344 #endif
345 
346 static const struct super_operations ext2_sops = {
347 	.alloc_inode	= ext2_alloc_inode,
348 	.free_inode	= ext2_free_in_core_inode,
349 	.write_inode	= ext2_write_inode,
350 	.evict_inode	= ext2_evict_inode,
351 	.put_super	= ext2_put_super,
352 	.sync_fs	= ext2_sync_fs,
353 	.freeze_fs	= ext2_freeze,
354 	.unfreeze_fs	= ext2_unfreeze,
355 	.statfs		= ext2_statfs,
356 	.remount_fs	= ext2_remount,
357 	.show_options	= ext2_show_options,
358 #ifdef CONFIG_QUOTA
359 	.quota_read	= ext2_quota_read,
360 	.quota_write	= ext2_quota_write,
361 	.get_dquots	= ext2_get_dquots,
362 #endif
363 };
364 
365 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
366 		u64 ino, u32 generation)
367 {
368 	struct inode *inode;
369 
370 	if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
371 		return ERR_PTR(-ESTALE);
372 	if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
373 		return ERR_PTR(-ESTALE);
374 
375 	/*
376 	 * ext2_iget isn't quite right if the inode is currently unallocated!
377 	 * However ext2_iget currently does appropriate checks to handle stale
378 	 * inodes so everything is OK.
379 	 */
380 	inode = ext2_iget(sb, ino);
381 	if (IS_ERR(inode))
382 		return ERR_CAST(inode);
383 	if (generation && inode->i_generation != generation) {
384 		/* we didn't find the right inode.. */
385 		iput(inode);
386 		return ERR_PTR(-ESTALE);
387 	}
388 	return inode;
389 }
390 
391 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
392 		int fh_len, int fh_type)
393 {
394 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
395 				    ext2_nfs_get_inode);
396 }
397 
398 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
399 		int fh_len, int fh_type)
400 {
401 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
402 				    ext2_nfs_get_inode);
403 }
404 
405 static const struct export_operations ext2_export_ops = {
406 	.fh_to_dentry = ext2_fh_to_dentry,
407 	.fh_to_parent = ext2_fh_to_parent,
408 	.get_parent = ext2_get_parent,
409 };
410 
411 static unsigned long get_sb_block(void **data)
412 {
413 	unsigned long 	sb_block;
414 	char 		*options = (char *) *data;
415 
416 	if (!options || strncmp(options, "sb=", 3) != 0)
417 		return 1;	/* Default location */
418 	options += 3;
419 	sb_block = simple_strtoul(options, &options, 0);
420 	if (*options && *options != ',') {
421 		printk("EXT2-fs: Invalid sb specification: %s\n",
422 		       (char *) *data);
423 		return 1;
424 	}
425 	if (*options == ',')
426 		options++;
427 	*data = (void *) options;
428 	return sb_block;
429 }
430 
431 enum {
432 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
433 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
434 	Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
435 	Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
436 	Opt_acl, Opt_noacl, Opt_xip, Opt_dax, Opt_ignore, Opt_err, Opt_quota,
437 	Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
438 };
439 
440 static const match_table_t tokens = {
441 	{Opt_bsd_df, "bsddf"},
442 	{Opt_minix_df, "minixdf"},
443 	{Opt_grpid, "grpid"},
444 	{Opt_grpid, "bsdgroups"},
445 	{Opt_nogrpid, "nogrpid"},
446 	{Opt_nogrpid, "sysvgroups"},
447 	{Opt_resgid, "resgid=%u"},
448 	{Opt_resuid, "resuid=%u"},
449 	{Opt_sb, "sb=%u"},
450 	{Opt_err_cont, "errors=continue"},
451 	{Opt_err_panic, "errors=panic"},
452 	{Opt_err_ro, "errors=remount-ro"},
453 	{Opt_nouid32, "nouid32"},
454 	{Opt_nocheck, "check=none"},
455 	{Opt_nocheck, "nocheck"},
456 	{Opt_debug, "debug"},
457 	{Opt_oldalloc, "oldalloc"},
458 	{Opt_orlov, "orlov"},
459 	{Opt_nobh, "nobh"},
460 	{Opt_user_xattr, "user_xattr"},
461 	{Opt_nouser_xattr, "nouser_xattr"},
462 	{Opt_acl, "acl"},
463 	{Opt_noacl, "noacl"},
464 	{Opt_xip, "xip"},
465 	{Opt_dax, "dax"},
466 	{Opt_grpquota, "grpquota"},
467 	{Opt_ignore, "noquota"},
468 	{Opt_quota, "quota"},
469 	{Opt_usrquota, "usrquota"},
470 	{Opt_reservation, "reservation"},
471 	{Opt_noreservation, "noreservation"},
472 	{Opt_err, NULL}
473 };
474 
475 static int parse_options(char *options, struct super_block *sb,
476 			 struct ext2_mount_options *opts)
477 {
478 	char *p;
479 	substring_t args[MAX_OPT_ARGS];
480 	int option;
481 	kuid_t uid;
482 	kgid_t gid;
483 
484 	if (!options)
485 		return 1;
486 
487 	while ((p = strsep (&options, ",")) != NULL) {
488 		int token;
489 		if (!*p)
490 			continue;
491 
492 		token = match_token(p, tokens, args);
493 		switch (token) {
494 		case Opt_bsd_df:
495 			clear_opt (opts->s_mount_opt, MINIX_DF);
496 			break;
497 		case Opt_minix_df:
498 			set_opt (opts->s_mount_opt, MINIX_DF);
499 			break;
500 		case Opt_grpid:
501 			set_opt (opts->s_mount_opt, GRPID);
502 			break;
503 		case Opt_nogrpid:
504 			clear_opt (opts->s_mount_opt, GRPID);
505 			break;
506 		case Opt_resuid:
507 			if (match_int(&args[0], &option))
508 				return 0;
509 			uid = make_kuid(current_user_ns(), option);
510 			if (!uid_valid(uid)) {
511 				ext2_msg(sb, KERN_ERR, "Invalid uid value %d", option);
512 				return 0;
513 
514 			}
515 			opts->s_resuid = uid;
516 			break;
517 		case Opt_resgid:
518 			if (match_int(&args[0], &option))
519 				return 0;
520 			gid = make_kgid(current_user_ns(), option);
521 			if (!gid_valid(gid)) {
522 				ext2_msg(sb, KERN_ERR, "Invalid gid value %d", option);
523 				return 0;
524 			}
525 			opts->s_resgid = gid;
526 			break;
527 		case Opt_sb:
528 			/* handled by get_sb_block() instead of here */
529 			/* *sb_block = match_int(&args[0]); */
530 			break;
531 		case Opt_err_panic:
532 			clear_opt (opts->s_mount_opt, ERRORS_CONT);
533 			clear_opt (opts->s_mount_opt, ERRORS_RO);
534 			set_opt (opts->s_mount_opt, ERRORS_PANIC);
535 			break;
536 		case Opt_err_ro:
537 			clear_opt (opts->s_mount_opt, ERRORS_CONT);
538 			clear_opt (opts->s_mount_opt, ERRORS_PANIC);
539 			set_opt (opts->s_mount_opt, ERRORS_RO);
540 			break;
541 		case Opt_err_cont:
542 			clear_opt (opts->s_mount_opt, ERRORS_RO);
543 			clear_opt (opts->s_mount_opt, ERRORS_PANIC);
544 			set_opt (opts->s_mount_opt, ERRORS_CONT);
545 			break;
546 		case Opt_nouid32:
547 			set_opt (opts->s_mount_opt, NO_UID32);
548 			break;
549 		case Opt_nocheck:
550 			ext2_msg(sb, KERN_WARNING,
551 				"Option nocheck/check=none is deprecated and"
552 				" will be removed in June 2020.");
553 			clear_opt (opts->s_mount_opt, CHECK);
554 			break;
555 		case Opt_debug:
556 			set_opt (opts->s_mount_opt, DEBUG);
557 			break;
558 		case Opt_oldalloc:
559 			set_opt (opts->s_mount_opt, OLDALLOC);
560 			break;
561 		case Opt_orlov:
562 			clear_opt (opts->s_mount_opt, OLDALLOC);
563 			break;
564 		case Opt_nobh:
565 			set_opt (opts->s_mount_opt, NOBH);
566 			break;
567 #ifdef CONFIG_EXT2_FS_XATTR
568 		case Opt_user_xattr:
569 			set_opt (opts->s_mount_opt, XATTR_USER);
570 			break;
571 		case Opt_nouser_xattr:
572 			clear_opt (opts->s_mount_opt, XATTR_USER);
573 			break;
574 #else
575 		case Opt_user_xattr:
576 		case Opt_nouser_xattr:
577 			ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
578 				"not supported");
579 			break;
580 #endif
581 #ifdef CONFIG_EXT2_FS_POSIX_ACL
582 		case Opt_acl:
583 			set_opt(opts->s_mount_opt, POSIX_ACL);
584 			break;
585 		case Opt_noacl:
586 			clear_opt(opts->s_mount_opt, POSIX_ACL);
587 			break;
588 #else
589 		case Opt_acl:
590 		case Opt_noacl:
591 			ext2_msg(sb, KERN_INFO,
592 				"(no)acl options not supported");
593 			break;
594 #endif
595 		case Opt_xip:
596 			ext2_msg(sb, KERN_INFO, "use dax instead of xip");
597 			set_opt(opts->s_mount_opt, XIP);
598 			/* Fall through */
599 		case Opt_dax:
600 #ifdef CONFIG_FS_DAX
601 			ext2_msg(sb, KERN_WARNING,
602 		"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
603 			set_opt(opts->s_mount_opt, DAX);
604 #else
605 			ext2_msg(sb, KERN_INFO, "dax option not supported");
606 #endif
607 			break;
608 
609 #if defined(CONFIG_QUOTA)
610 		case Opt_quota:
611 		case Opt_usrquota:
612 			set_opt(opts->s_mount_opt, USRQUOTA);
613 			break;
614 
615 		case Opt_grpquota:
616 			set_opt(opts->s_mount_opt, GRPQUOTA);
617 			break;
618 #else
619 		case Opt_quota:
620 		case Opt_usrquota:
621 		case Opt_grpquota:
622 			ext2_msg(sb, KERN_INFO,
623 				"quota operations not supported");
624 			break;
625 #endif
626 
627 		case Opt_reservation:
628 			set_opt(opts->s_mount_opt, RESERVATION);
629 			ext2_msg(sb, KERN_INFO, "reservations ON");
630 			break;
631 		case Opt_noreservation:
632 			clear_opt(opts->s_mount_opt, RESERVATION);
633 			ext2_msg(sb, KERN_INFO, "reservations OFF");
634 			break;
635 		case Opt_ignore:
636 			break;
637 		default:
638 			return 0;
639 		}
640 	}
641 	return 1;
642 }
643 
644 static int ext2_setup_super (struct super_block * sb,
645 			      struct ext2_super_block * es,
646 			      int read_only)
647 {
648 	int res = 0;
649 	struct ext2_sb_info *sbi = EXT2_SB(sb);
650 
651 	if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
652 		ext2_msg(sb, KERN_ERR,
653 			"error: revision level too high, "
654 			"forcing read-only mode");
655 		res = SB_RDONLY;
656 	}
657 	if (read_only)
658 		return res;
659 	if (!(sbi->s_mount_state & EXT2_VALID_FS))
660 		ext2_msg(sb, KERN_WARNING,
661 			"warning: mounting unchecked fs, "
662 			"running e2fsck is recommended");
663 	else if ((sbi->s_mount_state & EXT2_ERROR_FS))
664 		ext2_msg(sb, KERN_WARNING,
665 			"warning: mounting fs with errors, "
666 			"running e2fsck is recommended");
667 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
668 		 le16_to_cpu(es->s_mnt_count) >=
669 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
670 		ext2_msg(sb, KERN_WARNING,
671 			"warning: maximal mount count reached, "
672 			"running e2fsck is recommended");
673 	else if (le32_to_cpu(es->s_checkinterval) &&
674 		(le32_to_cpu(es->s_lastcheck) +
675 			le32_to_cpu(es->s_checkinterval) <=
676 			ktime_get_real_seconds()))
677 		ext2_msg(sb, KERN_WARNING,
678 			"warning: checktime reached, "
679 			"running e2fsck is recommended");
680 	if (!le16_to_cpu(es->s_max_mnt_count))
681 		es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
682 	le16_add_cpu(&es->s_mnt_count, 1);
683 	if (test_opt (sb, DEBUG))
684 		ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
685 			"bpg=%lu, ipg=%lu, mo=%04lx]",
686 			EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
687 			sbi->s_frag_size,
688 			sbi->s_groups_count,
689 			EXT2_BLOCKS_PER_GROUP(sb),
690 			EXT2_INODES_PER_GROUP(sb),
691 			sbi->s_mount_opt);
692 	return res;
693 }
694 
695 static int ext2_check_descriptors(struct super_block *sb)
696 {
697 	int i;
698 	struct ext2_sb_info *sbi = EXT2_SB(sb);
699 
700 	ext2_debug ("Checking group descriptors");
701 
702 	for (i = 0; i < sbi->s_groups_count; i++) {
703 		struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
704 		ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
705 		ext2_fsblk_t last_block;
706 
707 		if (i == sbi->s_groups_count - 1)
708 			last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
709 		else
710 			last_block = first_block +
711 				(EXT2_BLOCKS_PER_GROUP(sb) - 1);
712 
713 		if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
714 		    le32_to_cpu(gdp->bg_block_bitmap) > last_block)
715 		{
716 			ext2_error (sb, "ext2_check_descriptors",
717 				    "Block bitmap for group %d"
718 				    " not in group (block %lu)!",
719 				    i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
720 			return 0;
721 		}
722 		if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
723 		    le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
724 		{
725 			ext2_error (sb, "ext2_check_descriptors",
726 				    "Inode bitmap for group %d"
727 				    " not in group (block %lu)!",
728 				    i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
729 			return 0;
730 		}
731 		if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
732 		    le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
733 		    last_block)
734 		{
735 			ext2_error (sb, "ext2_check_descriptors",
736 				    "Inode table for group %d"
737 				    " not in group (block %lu)!",
738 				    i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
739 			return 0;
740 		}
741 	}
742 	return 1;
743 }
744 
745 /*
746  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
747  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
748  * We need to be 1 filesystem block less than the 2^32 sector limit.
749  */
750 static loff_t ext2_max_size(int bits)
751 {
752 	loff_t res = EXT2_NDIR_BLOCKS;
753 	int meta_blocks;
754 	unsigned int upper_limit;
755 	unsigned int ppb = 1 << (bits-2);
756 
757 	/* This is calculated to be the largest file size for a
758 	 * dense, file such that the total number of
759 	 * sectors in the file, including data and all indirect blocks,
760 	 * does not exceed 2^32 -1
761 	 * __u32 i_blocks representing the total number of
762 	 * 512 bytes blocks of the file
763 	 */
764 	upper_limit = (1LL << 32) - 1;
765 
766 	/* total blocks in file system block size */
767 	upper_limit >>= (bits - 9);
768 
769 	/* Compute how many blocks we can address by block tree */
770 	res += 1LL << (bits-2);
771 	res += 1LL << (2*(bits-2));
772 	res += 1LL << (3*(bits-2));
773 	/* Does block tree limit file size? */
774 	if (res < upper_limit)
775 		goto check_lfs;
776 
777 	res = upper_limit;
778 	/* How many metadata blocks are needed for addressing upper_limit? */
779 	upper_limit -= EXT2_NDIR_BLOCKS;
780 	/* indirect blocks */
781 	meta_blocks = 1;
782 	upper_limit -= ppb;
783 	/* double indirect blocks */
784 	if (upper_limit < ppb * ppb) {
785 		meta_blocks += 1 + DIV_ROUND_UP(upper_limit, ppb);
786 		res -= meta_blocks;
787 		goto check_lfs;
788 	}
789 	meta_blocks += 1 + ppb;
790 	upper_limit -= ppb * ppb;
791 	/* tripple indirect blocks for the rest */
792 	meta_blocks += 1 + DIV_ROUND_UP(upper_limit, ppb) +
793 		DIV_ROUND_UP(upper_limit, ppb*ppb);
794 	res -= meta_blocks;
795 check_lfs:
796 	res <<= bits;
797 	if (res > MAX_LFS_FILESIZE)
798 		res = MAX_LFS_FILESIZE;
799 
800 	return res;
801 }
802 
803 static unsigned long descriptor_loc(struct super_block *sb,
804 				    unsigned long logic_sb_block,
805 				    int nr)
806 {
807 	struct ext2_sb_info *sbi = EXT2_SB(sb);
808 	unsigned long bg, first_meta_bg;
809 	int has_super = 0;
810 
811 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
812 
813 	if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
814 	    nr < first_meta_bg)
815 		return (logic_sb_block + nr + 1);
816 	bg = sbi->s_desc_per_block * nr;
817 	if (ext2_bg_has_super(sb, bg))
818 		has_super = 1;
819 
820 	return ext2_group_first_block_no(sb, bg) + has_super;
821 }
822 
823 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
824 {
825 	struct dax_device *dax_dev = fs_dax_get_by_bdev(sb->s_bdev);
826 	struct buffer_head * bh;
827 	struct ext2_sb_info * sbi;
828 	struct ext2_super_block * es;
829 	struct inode *root;
830 	unsigned long block;
831 	unsigned long sb_block = get_sb_block(&data);
832 	unsigned long logic_sb_block;
833 	unsigned long offset = 0;
834 	unsigned long def_mount_opts;
835 	long ret = -ENOMEM;
836 	int blocksize = BLOCK_SIZE;
837 	int db_count;
838 	int i, j;
839 	__le32 features;
840 	int err;
841 	struct ext2_mount_options opts;
842 
843 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
844 	if (!sbi)
845 		goto failed;
846 
847 	sbi->s_blockgroup_lock =
848 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
849 	if (!sbi->s_blockgroup_lock) {
850 		kfree(sbi);
851 		goto failed;
852 	}
853 	sb->s_fs_info = sbi;
854 	sbi->s_sb_block = sb_block;
855 	sbi->s_daxdev = dax_dev;
856 
857 	spin_lock_init(&sbi->s_lock);
858 	ret = -EINVAL;
859 
860 	/*
861 	 * See what the current blocksize for the device is, and
862 	 * use that as the blocksize.  Otherwise (or if the blocksize
863 	 * is smaller than the default) use the default.
864 	 * This is important for devices that have a hardware
865 	 * sectorsize that is larger than the default.
866 	 */
867 	blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
868 	if (!blocksize) {
869 		ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
870 		goto failed_sbi;
871 	}
872 
873 	/*
874 	 * If the superblock doesn't start on a hardware sector boundary,
875 	 * calculate the offset.
876 	 */
877 	if (blocksize != BLOCK_SIZE) {
878 		logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
879 		offset = (sb_block*BLOCK_SIZE) % blocksize;
880 	} else {
881 		logic_sb_block = sb_block;
882 	}
883 
884 	if (!(bh = sb_bread(sb, logic_sb_block))) {
885 		ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
886 		goto failed_sbi;
887 	}
888 	/*
889 	 * Note: s_es must be initialized as soon as possible because
890 	 *       some ext2 macro-instructions depend on its value
891 	 */
892 	es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
893 	sbi->s_es = es;
894 	sb->s_magic = le16_to_cpu(es->s_magic);
895 
896 	if (sb->s_magic != EXT2_SUPER_MAGIC)
897 		goto cantfind_ext2;
898 
899 	opts.s_mount_opt = 0;
900 	/* Set defaults before we parse the mount options */
901 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
902 	if (def_mount_opts & EXT2_DEFM_DEBUG)
903 		set_opt(opts.s_mount_opt, DEBUG);
904 	if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
905 		set_opt(opts.s_mount_opt, GRPID);
906 	if (def_mount_opts & EXT2_DEFM_UID16)
907 		set_opt(opts.s_mount_opt, NO_UID32);
908 #ifdef CONFIG_EXT2_FS_XATTR
909 	if (def_mount_opts & EXT2_DEFM_XATTR_USER)
910 		set_opt(opts.s_mount_opt, XATTR_USER);
911 #endif
912 #ifdef CONFIG_EXT2_FS_POSIX_ACL
913 	if (def_mount_opts & EXT2_DEFM_ACL)
914 		set_opt(opts.s_mount_opt, POSIX_ACL);
915 #endif
916 
917 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
918 		set_opt(opts.s_mount_opt, ERRORS_PANIC);
919 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
920 		set_opt(opts.s_mount_opt, ERRORS_CONT);
921 	else
922 		set_opt(opts.s_mount_opt, ERRORS_RO);
923 
924 	opts.s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
925 	opts.s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
926 
927 	set_opt(opts.s_mount_opt, RESERVATION);
928 
929 	if (!parse_options((char *) data, sb, &opts))
930 		goto failed_mount;
931 
932 	sbi->s_mount_opt = opts.s_mount_opt;
933 	sbi->s_resuid = opts.s_resuid;
934 	sbi->s_resgid = opts.s_resgid;
935 
936 	sb->s_flags = (sb->s_flags & ~SB_POSIXACL) |
937 		((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
938 		 SB_POSIXACL : 0);
939 	sb->s_iflags |= SB_I_CGROUPWB;
940 
941 	if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
942 	    (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
943 	     EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
944 	     EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
945 		ext2_msg(sb, KERN_WARNING,
946 			"warning: feature flags set on rev 0 fs, "
947 			"running e2fsck is recommended");
948 	/*
949 	 * Check feature flags regardless of the revision level, since we
950 	 * previously didn't change the revision level when setting the flags,
951 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
952 	 */
953 	features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
954 	if (features) {
955 		ext2_msg(sb, KERN_ERR,	"error: couldn't mount because of "
956 		       "unsupported optional features (%x)",
957 			le32_to_cpu(features));
958 		goto failed_mount;
959 	}
960 	if (!sb_rdonly(sb) && (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
961 		ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
962 		       "unsupported optional features (%x)",
963 		       le32_to_cpu(features));
964 		goto failed_mount;
965 	}
966 
967 	blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
968 
969 	if (sbi->s_mount_opt & EXT2_MOUNT_DAX) {
970 		if (!bdev_dax_supported(sb->s_bdev, blocksize)) {
971 			ext2_msg(sb, KERN_ERR,
972 				"DAX unsupported by block device. Turning off DAX.");
973 			sbi->s_mount_opt &= ~EXT2_MOUNT_DAX;
974 		}
975 	}
976 
977 	/* If the blocksize doesn't match, re-read the thing.. */
978 	if (sb->s_blocksize != blocksize) {
979 		brelse(bh);
980 
981 		if (!sb_set_blocksize(sb, blocksize)) {
982 			ext2_msg(sb, KERN_ERR,
983 				"error: bad blocksize %d", blocksize);
984 			goto failed_sbi;
985 		}
986 
987 		logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
988 		offset = (sb_block*BLOCK_SIZE) % blocksize;
989 		bh = sb_bread(sb, logic_sb_block);
990 		if(!bh) {
991 			ext2_msg(sb, KERN_ERR, "error: couldn't read"
992 				"superblock on 2nd try");
993 			goto failed_sbi;
994 		}
995 		es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
996 		sbi->s_es = es;
997 		if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
998 			ext2_msg(sb, KERN_ERR, "error: magic mismatch");
999 			goto failed_mount;
1000 		}
1001 	}
1002 
1003 	sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
1004 	sb->s_max_links = EXT2_LINK_MAX;
1005 
1006 	if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
1007 		sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
1008 		sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
1009 	} else {
1010 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
1011 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
1012 		if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
1013 		    !is_power_of_2(sbi->s_inode_size) ||
1014 		    (sbi->s_inode_size > blocksize)) {
1015 			ext2_msg(sb, KERN_ERR,
1016 				"error: unsupported inode size: %d",
1017 				sbi->s_inode_size);
1018 			goto failed_mount;
1019 		}
1020 	}
1021 
1022 	sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
1023 				   le32_to_cpu(es->s_log_frag_size);
1024 	if (sbi->s_frag_size == 0)
1025 		goto cantfind_ext2;
1026 	sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
1027 
1028 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
1029 	sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
1030 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
1031 
1032 	sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
1033 	if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
1034 		goto cantfind_ext2;
1035 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
1036 					sbi->s_inodes_per_block;
1037 	sbi->s_desc_per_block = sb->s_blocksize /
1038 					sizeof (struct ext2_group_desc);
1039 	sbi->s_sbh = bh;
1040 	sbi->s_mount_state = le16_to_cpu(es->s_state);
1041 	sbi->s_addr_per_block_bits =
1042 		ilog2 (EXT2_ADDR_PER_BLOCK(sb));
1043 	sbi->s_desc_per_block_bits =
1044 		ilog2 (EXT2_DESC_PER_BLOCK(sb));
1045 
1046 	if (sb->s_magic != EXT2_SUPER_MAGIC)
1047 		goto cantfind_ext2;
1048 
1049 	if (sb->s_blocksize != bh->b_size) {
1050 		if (!silent)
1051 			ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
1052 		goto failed_mount;
1053 	}
1054 
1055 	if (sb->s_blocksize != sbi->s_frag_size) {
1056 		ext2_msg(sb, KERN_ERR,
1057 			"error: fragsize %lu != blocksize %lu"
1058 			"(not supported yet)",
1059 			sbi->s_frag_size, sb->s_blocksize);
1060 		goto failed_mount;
1061 	}
1062 
1063 	if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
1064 		ext2_msg(sb, KERN_ERR,
1065 			"error: #blocks per group too big: %lu",
1066 			sbi->s_blocks_per_group);
1067 		goto failed_mount;
1068 	}
1069 	if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
1070 		ext2_msg(sb, KERN_ERR,
1071 			"error: #fragments per group too big: %lu",
1072 			sbi->s_frags_per_group);
1073 		goto failed_mount;
1074 	}
1075 	if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
1076 		ext2_msg(sb, KERN_ERR,
1077 			"error: #inodes per group too big: %lu",
1078 			sbi->s_inodes_per_group);
1079 		goto failed_mount;
1080 	}
1081 
1082 	if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
1083 		goto cantfind_ext2;
1084  	sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
1085  				le32_to_cpu(es->s_first_data_block) - 1)
1086  					/ EXT2_BLOCKS_PER_GROUP(sb)) + 1;
1087 	db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
1088 		   EXT2_DESC_PER_BLOCK(sb);
1089 	sbi->s_group_desc = kmalloc_array (db_count,
1090 					   sizeof(struct buffer_head *),
1091 					   GFP_KERNEL);
1092 	if (sbi->s_group_desc == NULL) {
1093 		ret = -ENOMEM;
1094 		ext2_msg(sb, KERN_ERR, "error: not enough memory");
1095 		goto failed_mount;
1096 	}
1097 	bgl_lock_init(sbi->s_blockgroup_lock);
1098 	sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1099 	if (!sbi->s_debts) {
1100 		ret = -ENOMEM;
1101 		ext2_msg(sb, KERN_ERR, "error: not enough memory");
1102 		goto failed_mount_group_desc;
1103 	}
1104 	for (i = 0; i < db_count; i++) {
1105 		block = descriptor_loc(sb, logic_sb_block, i);
1106 		sbi->s_group_desc[i] = sb_bread(sb, block);
1107 		if (!sbi->s_group_desc[i]) {
1108 			for (j = 0; j < i; j++)
1109 				brelse (sbi->s_group_desc[j]);
1110 			ext2_msg(sb, KERN_ERR,
1111 				"error: unable to read group descriptors");
1112 			goto failed_mount_group_desc;
1113 		}
1114 	}
1115 	if (!ext2_check_descriptors (sb)) {
1116 		ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1117 		goto failed_mount2;
1118 	}
1119 	sbi->s_gdb_count = db_count;
1120 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1121 	spin_lock_init(&sbi->s_next_gen_lock);
1122 
1123 	/* per fileystem reservation list head & lock */
1124 	spin_lock_init(&sbi->s_rsv_window_lock);
1125 	sbi->s_rsv_window_root = RB_ROOT;
1126 	/*
1127 	 * Add a single, static dummy reservation to the start of the
1128 	 * reservation window list --- it gives us a placeholder for
1129 	 * append-at-start-of-list which makes the allocation logic
1130 	 * _much_ simpler.
1131 	 */
1132 	sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1133 	sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1134 	sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1135 	sbi->s_rsv_window_head.rsv_goal_size = 0;
1136 	ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1137 
1138 	err = percpu_counter_init(&sbi->s_freeblocks_counter,
1139 				ext2_count_free_blocks(sb), GFP_KERNEL);
1140 	if (!err) {
1141 		err = percpu_counter_init(&sbi->s_freeinodes_counter,
1142 				ext2_count_free_inodes(sb), GFP_KERNEL);
1143 	}
1144 	if (!err) {
1145 		err = percpu_counter_init(&sbi->s_dirs_counter,
1146 				ext2_count_dirs(sb), GFP_KERNEL);
1147 	}
1148 	if (err) {
1149 		ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1150 		goto failed_mount3;
1151 	}
1152 
1153 #ifdef CONFIG_EXT2_FS_XATTR
1154 	sbi->s_ea_block_cache = ext2_xattr_create_cache();
1155 	if (!sbi->s_ea_block_cache) {
1156 		ret = -ENOMEM;
1157 		ext2_msg(sb, KERN_ERR, "Failed to create ea_block_cache");
1158 		goto failed_mount3;
1159 	}
1160 #endif
1161 	/*
1162 	 * set up enough so that it can read an inode
1163 	 */
1164 	sb->s_op = &ext2_sops;
1165 	sb->s_export_op = &ext2_export_ops;
1166 	sb->s_xattr = ext2_xattr_handlers;
1167 
1168 #ifdef CONFIG_QUOTA
1169 	sb->dq_op = &dquot_operations;
1170 	sb->s_qcop = &ext2_quotactl_ops;
1171 	sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP;
1172 #endif
1173 
1174 	root = ext2_iget(sb, EXT2_ROOT_INO);
1175 	if (IS_ERR(root)) {
1176 		ret = PTR_ERR(root);
1177 		goto failed_mount3;
1178 	}
1179 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1180 		iput(root);
1181 		ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1182 		goto failed_mount3;
1183 	}
1184 
1185 	sb->s_root = d_make_root(root);
1186 	if (!sb->s_root) {
1187 		ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1188 		ret = -ENOMEM;
1189 		goto failed_mount3;
1190 	}
1191 	if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1192 		ext2_msg(sb, KERN_WARNING,
1193 			"warning: mounting ext3 filesystem as ext2");
1194 	if (ext2_setup_super (sb, es, sb_rdonly(sb)))
1195 		sb->s_flags |= SB_RDONLY;
1196 	ext2_write_super(sb);
1197 	return 0;
1198 
1199 cantfind_ext2:
1200 	if (!silent)
1201 		ext2_msg(sb, KERN_ERR,
1202 			"error: can't find an ext2 filesystem on dev %s.",
1203 			sb->s_id);
1204 	goto failed_mount;
1205 failed_mount3:
1206 	ext2_xattr_destroy_cache(sbi->s_ea_block_cache);
1207 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
1208 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
1209 	percpu_counter_destroy(&sbi->s_dirs_counter);
1210 failed_mount2:
1211 	for (i = 0; i < db_count; i++)
1212 		brelse(sbi->s_group_desc[i]);
1213 failed_mount_group_desc:
1214 	kfree(sbi->s_group_desc);
1215 	kfree(sbi->s_debts);
1216 failed_mount:
1217 	brelse(bh);
1218 failed_sbi:
1219 	sb->s_fs_info = NULL;
1220 	kfree(sbi->s_blockgroup_lock);
1221 	kfree(sbi);
1222 failed:
1223 	fs_put_dax(dax_dev);
1224 	return ret;
1225 }
1226 
1227 static void ext2_clear_super_error(struct super_block *sb)
1228 {
1229 	struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1230 
1231 	if (buffer_write_io_error(sbh)) {
1232 		/*
1233 		 * Oh, dear.  A previous attempt to write the
1234 		 * superblock failed.  This could happen because the
1235 		 * USB device was yanked out.  Or it could happen to
1236 		 * be a transient write error and maybe the block will
1237 		 * be remapped.  Nothing we can do but to retry the
1238 		 * write and hope for the best.
1239 		 */
1240 		ext2_msg(sb, KERN_ERR,
1241 		       "previous I/O error to superblock detected");
1242 		clear_buffer_write_io_error(sbh);
1243 		set_buffer_uptodate(sbh);
1244 	}
1245 }
1246 
1247 void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1248 		     int wait)
1249 {
1250 	ext2_clear_super_error(sb);
1251 	spin_lock(&EXT2_SB(sb)->s_lock);
1252 	es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1253 	es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1254 	es->s_wtime = cpu_to_le32(ktime_get_real_seconds());
1255 	/* unlock before we do IO */
1256 	spin_unlock(&EXT2_SB(sb)->s_lock);
1257 	mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1258 	if (wait)
1259 		sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1260 }
1261 
1262 /*
1263  * In the second extended file system, it is not necessary to
1264  * write the super block since we use a mapping of the
1265  * disk super block in a buffer.
1266  *
1267  * However, this function is still used to set the fs valid
1268  * flags to 0.  We need to set this flag to 0 since the fs
1269  * may have been checked while mounted and e2fsck may have
1270  * set s_state to EXT2_VALID_FS after some corrections.
1271  */
1272 static int ext2_sync_fs(struct super_block *sb, int wait)
1273 {
1274 	struct ext2_sb_info *sbi = EXT2_SB(sb);
1275 	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1276 
1277 	/*
1278 	 * Write quota structures to quota file, sync_blockdev() will write
1279 	 * them to disk later
1280 	 */
1281 	dquot_writeback_dquots(sb, -1);
1282 
1283 	spin_lock(&sbi->s_lock);
1284 	if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1285 		ext2_debug("setting valid to 0\n");
1286 		es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1287 	}
1288 	spin_unlock(&sbi->s_lock);
1289 	ext2_sync_super(sb, es, wait);
1290 	return 0;
1291 }
1292 
1293 static int ext2_freeze(struct super_block *sb)
1294 {
1295 	struct ext2_sb_info *sbi = EXT2_SB(sb);
1296 
1297 	/*
1298 	 * Open but unlinked files present? Keep EXT2_VALID_FS flag cleared
1299 	 * because we have unattached inodes and thus filesystem is not fully
1300 	 * consistent.
1301 	 */
1302 	if (atomic_long_read(&sb->s_remove_count)) {
1303 		ext2_sync_fs(sb, 1);
1304 		return 0;
1305 	}
1306 	/* Set EXT2_FS_VALID flag */
1307 	spin_lock(&sbi->s_lock);
1308 	sbi->s_es->s_state = cpu_to_le16(sbi->s_mount_state);
1309 	spin_unlock(&sbi->s_lock);
1310 	ext2_sync_super(sb, sbi->s_es, 1);
1311 
1312 	return 0;
1313 }
1314 
1315 static int ext2_unfreeze(struct super_block *sb)
1316 {
1317 	/* Just write sb to clear EXT2_VALID_FS flag */
1318 	ext2_write_super(sb);
1319 
1320 	return 0;
1321 }
1322 
1323 static void ext2_write_super(struct super_block *sb)
1324 {
1325 	if (!sb_rdonly(sb))
1326 		ext2_sync_fs(sb, 1);
1327 }
1328 
1329 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1330 {
1331 	struct ext2_sb_info * sbi = EXT2_SB(sb);
1332 	struct ext2_super_block * es;
1333 	struct ext2_mount_options new_opts;
1334 	int err;
1335 
1336 	sync_filesystem(sb);
1337 
1338 	spin_lock(&sbi->s_lock);
1339 	new_opts.s_mount_opt = sbi->s_mount_opt;
1340 	new_opts.s_resuid = sbi->s_resuid;
1341 	new_opts.s_resgid = sbi->s_resgid;
1342 	spin_unlock(&sbi->s_lock);
1343 
1344 	if (!parse_options(data, sb, &new_opts))
1345 		return -EINVAL;
1346 
1347 	spin_lock(&sbi->s_lock);
1348 	es = sbi->s_es;
1349 	if ((sbi->s_mount_opt ^ new_opts.s_mount_opt) & EXT2_MOUNT_DAX) {
1350 		ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1351 			 "dax flag with busy inodes while remounting");
1352 		new_opts.s_mount_opt ^= EXT2_MOUNT_DAX;
1353 	}
1354 	if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1355 		goto out_set;
1356 	if (*flags & SB_RDONLY) {
1357 		if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1358 		    !(sbi->s_mount_state & EXT2_VALID_FS))
1359 			goto out_set;
1360 
1361 		/*
1362 		 * OK, we are remounting a valid rw partition rdonly, so set
1363 		 * the rdonly flag and then mark the partition as valid again.
1364 		 */
1365 		es->s_state = cpu_to_le16(sbi->s_mount_state);
1366 		es->s_mtime = cpu_to_le32(ktime_get_real_seconds());
1367 		spin_unlock(&sbi->s_lock);
1368 
1369 		err = dquot_suspend(sb, -1);
1370 		if (err < 0)
1371 			return err;
1372 
1373 		ext2_sync_super(sb, es, 1);
1374 	} else {
1375 		__le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1376 					       ~EXT2_FEATURE_RO_COMPAT_SUPP);
1377 		if (ret) {
1378 			spin_unlock(&sbi->s_lock);
1379 			ext2_msg(sb, KERN_WARNING,
1380 				"warning: couldn't remount RDWR because of "
1381 				"unsupported optional features (%x).",
1382 				le32_to_cpu(ret));
1383 			return -EROFS;
1384 		}
1385 		/*
1386 		 * Mounting a RDONLY partition read-write, so reread and
1387 		 * store the current valid flag.  (It may have been changed
1388 		 * by e2fsck since we originally mounted the partition.)
1389 		 */
1390 		sbi->s_mount_state = le16_to_cpu(es->s_state);
1391 		if (!ext2_setup_super (sb, es, 0))
1392 			sb->s_flags &= ~SB_RDONLY;
1393 		spin_unlock(&sbi->s_lock);
1394 
1395 		ext2_write_super(sb);
1396 
1397 		dquot_resume(sb, -1);
1398 	}
1399 
1400 	spin_lock(&sbi->s_lock);
1401 out_set:
1402 	sbi->s_mount_opt = new_opts.s_mount_opt;
1403 	sbi->s_resuid = new_opts.s_resuid;
1404 	sbi->s_resgid = new_opts.s_resgid;
1405 	sb->s_flags = (sb->s_flags & ~SB_POSIXACL) |
1406 		((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? SB_POSIXACL : 0);
1407 	spin_unlock(&sbi->s_lock);
1408 
1409 	return 0;
1410 }
1411 
1412 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1413 {
1414 	struct super_block *sb = dentry->d_sb;
1415 	struct ext2_sb_info *sbi = EXT2_SB(sb);
1416 	struct ext2_super_block *es = sbi->s_es;
1417 	u64 fsid;
1418 
1419 	spin_lock(&sbi->s_lock);
1420 
1421 	if (test_opt (sb, MINIX_DF))
1422 		sbi->s_overhead_last = 0;
1423 	else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1424 		unsigned long i, overhead = 0;
1425 		smp_rmb();
1426 
1427 		/*
1428 		 * Compute the overhead (FS structures). This is constant
1429 		 * for a given filesystem unless the number of block groups
1430 		 * changes so we cache the previous value until it does.
1431 		 */
1432 
1433 		/*
1434 		 * All of the blocks before first_data_block are
1435 		 * overhead
1436 		 */
1437 		overhead = le32_to_cpu(es->s_first_data_block);
1438 
1439 		/*
1440 		 * Add the overhead attributed to the superblock and
1441 		 * block group descriptors.  If the sparse superblocks
1442 		 * feature is turned on, then not all groups have this.
1443 		 */
1444 		for (i = 0; i < sbi->s_groups_count; i++)
1445 			overhead += ext2_bg_has_super(sb, i) +
1446 				ext2_bg_num_gdb(sb, i);
1447 
1448 		/*
1449 		 * Every block group has an inode bitmap, a block
1450 		 * bitmap, and an inode table.
1451 		 */
1452 		overhead += (sbi->s_groups_count *
1453 			     (2 + sbi->s_itb_per_group));
1454 		sbi->s_overhead_last = overhead;
1455 		smp_wmb();
1456 		sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1457 	}
1458 
1459 	buf->f_type = EXT2_SUPER_MAGIC;
1460 	buf->f_bsize = sb->s_blocksize;
1461 	buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1462 	buf->f_bfree = ext2_count_free_blocks(sb);
1463 	es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1464 	buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1465 	if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1466 		buf->f_bavail = 0;
1467 	buf->f_files = le32_to_cpu(es->s_inodes_count);
1468 	buf->f_ffree = ext2_count_free_inodes(sb);
1469 	es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1470 	buf->f_namelen = EXT2_NAME_LEN;
1471 	fsid = le64_to_cpup((void *)es->s_uuid) ^
1472 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1473 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1474 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1475 	spin_unlock(&sbi->s_lock);
1476 	return 0;
1477 }
1478 
1479 static struct dentry *ext2_mount(struct file_system_type *fs_type,
1480 	int flags, const char *dev_name, void *data)
1481 {
1482 	return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1483 }
1484 
1485 #ifdef CONFIG_QUOTA
1486 
1487 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1488  * acquiring the locks... As quota files are never truncated and quota code
1489  * itself serializes the operations (and no one else should touch the files)
1490  * we don't have to be afraid of races */
1491 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1492 			       size_t len, loff_t off)
1493 {
1494 	struct inode *inode = sb_dqopt(sb)->files[type];
1495 	sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1496 	int err = 0;
1497 	int offset = off & (sb->s_blocksize - 1);
1498 	int tocopy;
1499 	size_t toread;
1500 	struct buffer_head tmp_bh;
1501 	struct buffer_head *bh;
1502 	loff_t i_size = i_size_read(inode);
1503 
1504 	if (off > i_size)
1505 		return 0;
1506 	if (off+len > i_size)
1507 		len = i_size-off;
1508 	toread = len;
1509 	while (toread > 0) {
1510 		tocopy = sb->s_blocksize - offset < toread ?
1511 				sb->s_blocksize - offset : toread;
1512 
1513 		tmp_bh.b_state = 0;
1514 		tmp_bh.b_size = sb->s_blocksize;
1515 		err = ext2_get_block(inode, blk, &tmp_bh, 0);
1516 		if (err < 0)
1517 			return err;
1518 		if (!buffer_mapped(&tmp_bh))	/* A hole? */
1519 			memset(data, 0, tocopy);
1520 		else {
1521 			bh = sb_bread(sb, tmp_bh.b_blocknr);
1522 			if (!bh)
1523 				return -EIO;
1524 			memcpy(data, bh->b_data+offset, tocopy);
1525 			brelse(bh);
1526 		}
1527 		offset = 0;
1528 		toread -= tocopy;
1529 		data += tocopy;
1530 		blk++;
1531 	}
1532 	return len;
1533 }
1534 
1535 /* Write to quotafile */
1536 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1537 				const char *data, size_t len, loff_t off)
1538 {
1539 	struct inode *inode = sb_dqopt(sb)->files[type];
1540 	sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1541 	int err = 0;
1542 	int offset = off & (sb->s_blocksize - 1);
1543 	int tocopy;
1544 	size_t towrite = len;
1545 	struct buffer_head tmp_bh;
1546 	struct buffer_head *bh;
1547 
1548 	while (towrite > 0) {
1549 		tocopy = sb->s_blocksize - offset < towrite ?
1550 				sb->s_blocksize - offset : towrite;
1551 
1552 		tmp_bh.b_state = 0;
1553 		tmp_bh.b_size = sb->s_blocksize;
1554 		err = ext2_get_block(inode, blk, &tmp_bh, 1);
1555 		if (err < 0)
1556 			goto out;
1557 		if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1558 			bh = sb_bread(sb, tmp_bh.b_blocknr);
1559 		else
1560 			bh = sb_getblk(sb, tmp_bh.b_blocknr);
1561 		if (unlikely(!bh)) {
1562 			err = -EIO;
1563 			goto out;
1564 		}
1565 		lock_buffer(bh);
1566 		memcpy(bh->b_data+offset, data, tocopy);
1567 		flush_dcache_page(bh->b_page);
1568 		set_buffer_uptodate(bh);
1569 		mark_buffer_dirty(bh);
1570 		unlock_buffer(bh);
1571 		brelse(bh);
1572 		offset = 0;
1573 		towrite -= tocopy;
1574 		data += tocopy;
1575 		blk++;
1576 	}
1577 out:
1578 	if (len == towrite)
1579 		return err;
1580 	if (inode->i_size < off+len-towrite)
1581 		i_size_write(inode, off+len-towrite);
1582 	inode_inc_iversion(inode);
1583 	inode->i_mtime = inode->i_ctime = current_time(inode);
1584 	mark_inode_dirty(inode);
1585 	return len - towrite;
1586 }
1587 
1588 static int ext2_quota_on(struct super_block *sb, int type, int format_id,
1589 			 const struct path *path)
1590 {
1591 	int err;
1592 	struct inode *inode;
1593 
1594 	err = dquot_quota_on(sb, type, format_id, path);
1595 	if (err)
1596 		return err;
1597 
1598 	inode = d_inode(path->dentry);
1599 	inode_lock(inode);
1600 	EXT2_I(inode)->i_flags |= EXT2_NOATIME_FL | EXT2_IMMUTABLE_FL;
1601 	inode_set_flags(inode, S_NOATIME | S_IMMUTABLE,
1602 			S_NOATIME | S_IMMUTABLE);
1603 	inode_unlock(inode);
1604 	mark_inode_dirty(inode);
1605 
1606 	return 0;
1607 }
1608 
1609 static int ext2_quota_off(struct super_block *sb, int type)
1610 {
1611 	struct inode *inode = sb_dqopt(sb)->files[type];
1612 	int err;
1613 
1614 	if (!inode || !igrab(inode))
1615 		goto out;
1616 
1617 	err = dquot_quota_off(sb, type);
1618 	if (err)
1619 		goto out_put;
1620 
1621 	inode_lock(inode);
1622 	EXT2_I(inode)->i_flags &= ~(EXT2_NOATIME_FL | EXT2_IMMUTABLE_FL);
1623 	inode_set_flags(inode, 0, S_NOATIME | S_IMMUTABLE);
1624 	inode_unlock(inode);
1625 	mark_inode_dirty(inode);
1626 out_put:
1627 	iput(inode);
1628 	return err;
1629 out:
1630 	return dquot_quota_off(sb, type);
1631 }
1632 
1633 #endif
1634 
1635 static struct file_system_type ext2_fs_type = {
1636 	.owner		= THIS_MODULE,
1637 	.name		= "ext2",
1638 	.mount		= ext2_mount,
1639 	.kill_sb	= kill_block_super,
1640 	.fs_flags	= FS_REQUIRES_DEV,
1641 };
1642 MODULE_ALIAS_FS("ext2");
1643 
1644 static int __init init_ext2_fs(void)
1645 {
1646 	int err;
1647 
1648 	err = init_inodecache();
1649 	if (err)
1650 		return err;
1651         err = register_filesystem(&ext2_fs_type);
1652 	if (err)
1653 		goto out;
1654 	return 0;
1655 out:
1656 	destroy_inodecache();
1657 	return err;
1658 }
1659 
1660 static void __exit exit_ext2_fs(void)
1661 {
1662 	unregister_filesystem(&ext2_fs_type);
1663 	destroy_inodecache();
1664 }
1665 
1666 MODULE_AUTHOR("Remy Card and others");
1667 MODULE_DESCRIPTION("Second Extended Filesystem");
1668 MODULE_LICENSE("GPL");
1669 module_init(init_ext2_fs)
1670 module_exit(exit_ext2_fs)
1671