xref: /openbmc/linux/fs/ext2/super.c (revision 4a3fad70)
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 "ext2.h"
37 #include "xattr.h"
38 #include "acl.h"
39 
40 static void ext2_write_super(struct super_block *sb);
41 static int ext2_remount (struct super_block * sb, int * flags, char * data);
42 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
43 static int ext2_sync_fs(struct super_block *sb, int wait);
44 static int ext2_freeze(struct super_block *sb);
45 static int ext2_unfreeze(struct super_block *sb);
46 
47 void ext2_error(struct super_block *sb, const char *function,
48 		const char *fmt, ...)
49 {
50 	struct va_format vaf;
51 	va_list args;
52 	struct ext2_sb_info *sbi = EXT2_SB(sb);
53 	struct ext2_super_block *es = sbi->s_es;
54 
55 	if (!sb_rdonly(sb)) {
56 		spin_lock(&sbi->s_lock);
57 		sbi->s_mount_state |= EXT2_ERROR_FS;
58 		es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
59 		spin_unlock(&sbi->s_lock);
60 		ext2_sync_super(sb, es, 1);
61 	}
62 
63 	va_start(args, fmt);
64 
65 	vaf.fmt = fmt;
66 	vaf.va = &args;
67 
68 	printk(KERN_CRIT "EXT2-fs (%s): error: %s: %pV\n",
69 	       sb->s_id, function, &vaf);
70 
71 	va_end(args);
72 
73 	if (test_opt(sb, ERRORS_PANIC))
74 		panic("EXT2-fs: panic from previous error\n");
75 	if (test_opt(sb, ERRORS_RO)) {
76 		ext2_msg(sb, KERN_CRIT,
77 			     "error: remounting filesystem read-only");
78 		sb->s_flags |= SB_RDONLY;
79 	}
80 }
81 
82 void ext2_msg(struct super_block *sb, const char *prefix,
83 		const char *fmt, ...)
84 {
85 	struct va_format vaf;
86 	va_list args;
87 
88 	va_start(args, fmt);
89 
90 	vaf.fmt = fmt;
91 	vaf.va = &args;
92 
93 	printk("%sEXT2-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
94 
95 	va_end(args);
96 }
97 
98 /*
99  * This must be called with sbi->s_lock held.
100  */
101 void ext2_update_dynamic_rev(struct super_block *sb)
102 {
103 	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
104 
105 	if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
106 		return;
107 
108 	ext2_msg(sb, KERN_WARNING,
109 		     "warning: updating to rev %d because of "
110 		     "new feature flag, running e2fsck is recommended",
111 		     EXT2_DYNAMIC_REV);
112 
113 	es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
114 	es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
115 	es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
116 	/* leave es->s_feature_*compat flags alone */
117 	/* es->s_uuid will be set by e2fsck if empty */
118 
119 	/*
120 	 * The rest of the superblock fields should be zero, and if not it
121 	 * means they are likely already in use, so leave them alone.  We
122 	 * can leave it up to e2fsck to clean up any inconsistencies there.
123 	 */
124 }
125 
126 #ifdef CONFIG_QUOTA
127 static int ext2_quota_off(struct super_block *sb, int type);
128 
129 static void ext2_quota_off_umount(struct super_block *sb)
130 {
131 	int type;
132 
133 	for (type = 0; type < MAXQUOTAS; type++)
134 		ext2_quota_off(sb, type);
135 }
136 #else
137 static inline void ext2_quota_off_umount(struct super_block *sb)
138 {
139 }
140 #endif
141 
142 static void ext2_put_super (struct super_block * sb)
143 {
144 	int db_count;
145 	int i;
146 	struct ext2_sb_info *sbi = EXT2_SB(sb);
147 
148 	ext2_quota_off_umount(sb);
149 
150 	if (sbi->s_ea_block_cache) {
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 	ei->vfs_inode.i_version = 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("ext2_inode_cache",
224 					     sizeof(struct ext2_inode_info),
225 					     0, (SLAB_RECLAIM_ACCOUNT|
226 						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
227 					     init_once);
228 	if (ext2_inode_cachep == NULL)
229 		return -ENOMEM;
230 	return 0;
231 }
232 
233 static void destroy_inodecache(void)
234 {
235 	/*
236 	 * Make sure all delayed rcu free inodes are flushed before we
237 	 * destroy cache.
238 	 */
239 	rcu_barrier();
240 	kmem_cache_destroy(ext2_inode_cachep);
241 }
242 
243 static int ext2_show_options(struct seq_file *seq, struct dentry *root)
244 {
245 	struct super_block *sb = root->d_sb;
246 	struct ext2_sb_info *sbi = EXT2_SB(sb);
247 	struct ext2_super_block *es = sbi->s_es;
248 	unsigned long def_mount_opts;
249 
250 	spin_lock(&sbi->s_lock);
251 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
252 
253 	if (sbi->s_sb_block != 1)
254 		seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
255 	if (test_opt(sb, MINIX_DF))
256 		seq_puts(seq, ",minixdf");
257 	if (test_opt(sb, GRPID))
258 		seq_puts(seq, ",grpid");
259 	if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
260 		seq_puts(seq, ",nogrpid");
261 	if (!uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT2_DEF_RESUID)) ||
262 	    le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
263 		seq_printf(seq, ",resuid=%u",
264 				from_kuid_munged(&init_user_ns, sbi->s_resuid));
265 	}
266 	if (!gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT2_DEF_RESGID)) ||
267 	    le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
268 		seq_printf(seq, ",resgid=%u",
269 				from_kgid_munged(&init_user_ns, sbi->s_resgid));
270 	}
271 	if (test_opt(sb, ERRORS_RO)) {
272 		int def_errors = le16_to_cpu(es->s_errors);
273 
274 		if (def_errors == EXT2_ERRORS_PANIC ||
275 		    def_errors == EXT2_ERRORS_CONTINUE) {
276 			seq_puts(seq, ",errors=remount-ro");
277 		}
278 	}
279 	if (test_opt(sb, ERRORS_CONT))
280 		seq_puts(seq, ",errors=continue");
281 	if (test_opt(sb, ERRORS_PANIC))
282 		seq_puts(seq, ",errors=panic");
283 	if (test_opt(sb, NO_UID32))
284 		seq_puts(seq, ",nouid32");
285 	if (test_opt(sb, DEBUG))
286 		seq_puts(seq, ",debug");
287 	if (test_opt(sb, OLDALLOC))
288 		seq_puts(seq, ",oldalloc");
289 
290 #ifdef CONFIG_EXT2_FS_XATTR
291 	if (test_opt(sb, XATTR_USER))
292 		seq_puts(seq, ",user_xattr");
293 	if (!test_opt(sb, XATTR_USER) &&
294 	    (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
295 		seq_puts(seq, ",nouser_xattr");
296 	}
297 #endif
298 
299 #ifdef CONFIG_EXT2_FS_POSIX_ACL
300 	if (test_opt(sb, POSIX_ACL))
301 		seq_puts(seq, ",acl");
302 	if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
303 		seq_puts(seq, ",noacl");
304 #endif
305 
306 	if (test_opt(sb, NOBH))
307 		seq_puts(seq, ",nobh");
308 
309 #if defined(CONFIG_QUOTA)
310 	if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
311 		seq_puts(seq, ",usrquota");
312 
313 	if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
314 		seq_puts(seq, ",grpquota");
315 #endif
316 
317 #ifdef CONFIG_FS_DAX
318 	if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
319 		seq_puts(seq, ",xip");
320 	if (sbi->s_mount_opt & EXT2_MOUNT_DAX)
321 		seq_puts(seq, ",dax");
322 #endif
323 
324 	if (!test_opt(sb, RESERVATION))
325 		seq_puts(seq, ",noreservation");
326 
327 	spin_unlock(&sbi->s_lock);
328 	return 0;
329 }
330 
331 #ifdef CONFIG_QUOTA
332 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
333 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
334 static int ext2_quota_on(struct super_block *sb, int type, int format_id,
335 			 const struct path *path);
336 static struct dquot **ext2_get_dquots(struct inode *inode)
337 {
338 	return EXT2_I(inode)->i_dquot;
339 }
340 
341 static const struct quotactl_ops ext2_quotactl_ops = {
342 	.quota_on	= ext2_quota_on,
343 	.quota_off	= ext2_quota_off,
344 	.quota_sync	= dquot_quota_sync,
345 	.get_state	= dquot_get_state,
346 	.set_info	= dquot_set_dqinfo,
347 	.get_dqblk	= dquot_get_dqblk,
348 	.set_dqblk	= dquot_set_dqblk,
349 	.get_nextdqblk	= dquot_get_next_dqblk,
350 };
351 #endif
352 
353 static const struct super_operations ext2_sops = {
354 	.alloc_inode	= ext2_alloc_inode,
355 	.destroy_inode	= ext2_destroy_inode,
356 	.write_inode	= ext2_write_inode,
357 	.evict_inode	= ext2_evict_inode,
358 	.put_super	= ext2_put_super,
359 	.sync_fs	= ext2_sync_fs,
360 	.freeze_fs	= ext2_freeze,
361 	.unfreeze_fs	= ext2_unfreeze,
362 	.statfs		= ext2_statfs,
363 	.remount_fs	= ext2_remount,
364 	.show_options	= ext2_show_options,
365 #ifdef CONFIG_QUOTA
366 	.quota_read	= ext2_quota_read,
367 	.quota_write	= ext2_quota_write,
368 	.get_dquots	= ext2_get_dquots,
369 #endif
370 };
371 
372 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
373 		u64 ino, u32 generation)
374 {
375 	struct inode *inode;
376 
377 	if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
378 		return ERR_PTR(-ESTALE);
379 	if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
380 		return ERR_PTR(-ESTALE);
381 
382 	/*
383 	 * ext2_iget isn't quite right if the inode is currently unallocated!
384 	 * However ext2_iget currently does appropriate checks to handle stale
385 	 * inodes so everything is OK.
386 	 */
387 	inode = ext2_iget(sb, ino);
388 	if (IS_ERR(inode))
389 		return ERR_CAST(inode);
390 	if (generation && inode->i_generation != generation) {
391 		/* we didn't find the right inode.. */
392 		iput(inode);
393 		return ERR_PTR(-ESTALE);
394 	}
395 	return inode;
396 }
397 
398 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
399 		int fh_len, int fh_type)
400 {
401 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
402 				    ext2_nfs_get_inode);
403 }
404 
405 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
406 		int fh_len, int fh_type)
407 {
408 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
409 				    ext2_nfs_get_inode);
410 }
411 
412 static const struct export_operations ext2_export_ops = {
413 	.fh_to_dentry = ext2_fh_to_dentry,
414 	.fh_to_parent = ext2_fh_to_parent,
415 	.get_parent = ext2_get_parent,
416 };
417 
418 static unsigned long get_sb_block(void **data)
419 {
420 	unsigned long 	sb_block;
421 	char 		*options = (char *) *data;
422 
423 	if (!options || strncmp(options, "sb=", 3) != 0)
424 		return 1;	/* Default location */
425 	options += 3;
426 	sb_block = simple_strtoul(options, &options, 0);
427 	if (*options && *options != ',') {
428 		printk("EXT2-fs: Invalid sb specification: %s\n",
429 		       (char *) *data);
430 		return 1;
431 	}
432 	if (*options == ',')
433 		options++;
434 	*data = (void *) options;
435 	return sb_block;
436 }
437 
438 enum {
439 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
440 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
441 	Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
442 	Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
443 	Opt_acl, Opt_noacl, Opt_xip, Opt_dax, Opt_ignore, Opt_err, Opt_quota,
444 	Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
445 };
446 
447 static const match_table_t tokens = {
448 	{Opt_bsd_df, "bsddf"},
449 	{Opt_minix_df, "minixdf"},
450 	{Opt_grpid, "grpid"},
451 	{Opt_grpid, "bsdgroups"},
452 	{Opt_nogrpid, "nogrpid"},
453 	{Opt_nogrpid, "sysvgroups"},
454 	{Opt_resgid, "resgid=%u"},
455 	{Opt_resuid, "resuid=%u"},
456 	{Opt_sb, "sb=%u"},
457 	{Opt_err_cont, "errors=continue"},
458 	{Opt_err_panic, "errors=panic"},
459 	{Opt_err_ro, "errors=remount-ro"},
460 	{Opt_nouid32, "nouid32"},
461 	{Opt_nocheck, "check=none"},
462 	{Opt_nocheck, "nocheck"},
463 	{Opt_debug, "debug"},
464 	{Opt_oldalloc, "oldalloc"},
465 	{Opt_orlov, "orlov"},
466 	{Opt_nobh, "nobh"},
467 	{Opt_user_xattr, "user_xattr"},
468 	{Opt_nouser_xattr, "nouser_xattr"},
469 	{Opt_acl, "acl"},
470 	{Opt_noacl, "noacl"},
471 	{Opt_xip, "xip"},
472 	{Opt_dax, "dax"},
473 	{Opt_grpquota, "grpquota"},
474 	{Opt_ignore, "noquota"},
475 	{Opt_quota, "quota"},
476 	{Opt_usrquota, "usrquota"},
477 	{Opt_reservation, "reservation"},
478 	{Opt_noreservation, "noreservation"},
479 	{Opt_err, NULL}
480 };
481 
482 static int parse_options(char *options, struct super_block *sb,
483 			 struct ext2_mount_options *opts)
484 {
485 	char *p;
486 	substring_t args[MAX_OPT_ARGS];
487 	int option;
488 	kuid_t uid;
489 	kgid_t gid;
490 
491 	if (!options)
492 		return 1;
493 
494 	while ((p = strsep (&options, ",")) != NULL) {
495 		int token;
496 		if (!*p)
497 			continue;
498 
499 		token = match_token(p, tokens, args);
500 		switch (token) {
501 		case Opt_bsd_df:
502 			clear_opt (opts->s_mount_opt, MINIX_DF);
503 			break;
504 		case Opt_minix_df:
505 			set_opt (opts->s_mount_opt, MINIX_DF);
506 			break;
507 		case Opt_grpid:
508 			set_opt (opts->s_mount_opt, GRPID);
509 			break;
510 		case Opt_nogrpid:
511 			clear_opt (opts->s_mount_opt, GRPID);
512 			break;
513 		case Opt_resuid:
514 			if (match_int(&args[0], &option))
515 				return 0;
516 			uid = make_kuid(current_user_ns(), option);
517 			if (!uid_valid(uid)) {
518 				ext2_msg(sb, KERN_ERR, "Invalid uid value %d", option);
519 				return 0;
520 
521 			}
522 			opts->s_resuid = uid;
523 			break;
524 		case Opt_resgid:
525 			if (match_int(&args[0], &option))
526 				return 0;
527 			gid = make_kgid(current_user_ns(), option);
528 			if (!gid_valid(gid)) {
529 				ext2_msg(sb, KERN_ERR, "Invalid gid value %d", option);
530 				return 0;
531 			}
532 			opts->s_resgid = gid;
533 			break;
534 		case Opt_sb:
535 			/* handled by get_sb_block() instead of here */
536 			/* *sb_block = match_int(&args[0]); */
537 			break;
538 		case Opt_err_panic:
539 			clear_opt (opts->s_mount_opt, ERRORS_CONT);
540 			clear_opt (opts->s_mount_opt, ERRORS_RO);
541 			set_opt (opts->s_mount_opt, ERRORS_PANIC);
542 			break;
543 		case Opt_err_ro:
544 			clear_opt (opts->s_mount_opt, ERRORS_CONT);
545 			clear_opt (opts->s_mount_opt, ERRORS_PANIC);
546 			set_opt (opts->s_mount_opt, ERRORS_RO);
547 			break;
548 		case Opt_err_cont:
549 			clear_opt (opts->s_mount_opt, ERRORS_RO);
550 			clear_opt (opts->s_mount_opt, ERRORS_PANIC);
551 			set_opt (opts->s_mount_opt, ERRORS_CONT);
552 			break;
553 		case Opt_nouid32:
554 			set_opt (opts->s_mount_opt, NO_UID32);
555 			break;
556 		case Opt_nocheck:
557 			clear_opt (opts->s_mount_opt, CHECK);
558 			break;
559 		case Opt_debug:
560 			set_opt (opts->s_mount_opt, DEBUG);
561 			break;
562 		case Opt_oldalloc:
563 			set_opt (opts->s_mount_opt, OLDALLOC);
564 			break;
565 		case Opt_orlov:
566 			clear_opt (opts->s_mount_opt, OLDALLOC);
567 			break;
568 		case Opt_nobh:
569 			set_opt (opts->s_mount_opt, NOBH);
570 			break;
571 #ifdef CONFIG_EXT2_FS_XATTR
572 		case Opt_user_xattr:
573 			set_opt (opts->s_mount_opt, XATTR_USER);
574 			break;
575 		case Opt_nouser_xattr:
576 			clear_opt (opts->s_mount_opt, XATTR_USER);
577 			break;
578 #else
579 		case Opt_user_xattr:
580 		case Opt_nouser_xattr:
581 			ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
582 				"not supported");
583 			break;
584 #endif
585 #ifdef CONFIG_EXT2_FS_POSIX_ACL
586 		case Opt_acl:
587 			set_opt(opts->s_mount_opt, POSIX_ACL);
588 			break;
589 		case Opt_noacl:
590 			clear_opt(opts->s_mount_opt, POSIX_ACL);
591 			break;
592 #else
593 		case Opt_acl:
594 		case Opt_noacl:
595 			ext2_msg(sb, KERN_INFO,
596 				"(no)acl options not supported");
597 			break;
598 #endif
599 		case Opt_xip:
600 			ext2_msg(sb, KERN_INFO, "use dax instead of xip");
601 			set_opt(opts->s_mount_opt, XIP);
602 			/* Fall through */
603 		case Opt_dax:
604 #ifdef CONFIG_FS_DAX
605 			ext2_msg(sb, KERN_WARNING,
606 		"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
607 			set_opt(opts->s_mount_opt, DAX);
608 #else
609 			ext2_msg(sb, KERN_INFO, "dax option not supported");
610 #endif
611 			break;
612 
613 #if defined(CONFIG_QUOTA)
614 		case Opt_quota:
615 		case Opt_usrquota:
616 			set_opt(opts->s_mount_opt, USRQUOTA);
617 			break;
618 
619 		case Opt_grpquota:
620 			set_opt(opts->s_mount_opt, GRPQUOTA);
621 			break;
622 #else
623 		case Opt_quota:
624 		case Opt_usrquota:
625 		case Opt_grpquota:
626 			ext2_msg(sb, KERN_INFO,
627 				"quota operations not supported");
628 			break;
629 #endif
630 
631 		case Opt_reservation:
632 			set_opt(opts->s_mount_opt, RESERVATION);
633 			ext2_msg(sb, KERN_INFO, "reservations ON");
634 			break;
635 		case Opt_noreservation:
636 			clear_opt(opts->s_mount_opt, RESERVATION);
637 			ext2_msg(sb, KERN_INFO, "reservations OFF");
638 			break;
639 		case Opt_ignore:
640 			break;
641 		default:
642 			return 0;
643 		}
644 	}
645 	return 1;
646 }
647 
648 static int ext2_setup_super (struct super_block * sb,
649 			      struct ext2_super_block * es,
650 			      int read_only)
651 {
652 	int res = 0;
653 	struct ext2_sb_info *sbi = EXT2_SB(sb);
654 
655 	if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
656 		ext2_msg(sb, KERN_ERR,
657 			"error: revision level too high, "
658 			"forcing read-only mode");
659 		res = SB_RDONLY;
660 	}
661 	if (read_only)
662 		return res;
663 	if (!(sbi->s_mount_state & EXT2_VALID_FS))
664 		ext2_msg(sb, KERN_WARNING,
665 			"warning: mounting unchecked fs, "
666 			"running e2fsck is recommended");
667 	else if ((sbi->s_mount_state & EXT2_ERROR_FS))
668 		ext2_msg(sb, KERN_WARNING,
669 			"warning: mounting fs with errors, "
670 			"running e2fsck is recommended");
671 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
672 		 le16_to_cpu(es->s_mnt_count) >=
673 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
674 		ext2_msg(sb, KERN_WARNING,
675 			"warning: maximal mount count reached, "
676 			"running e2fsck is recommended");
677 	else if (le32_to_cpu(es->s_checkinterval) &&
678 		(le32_to_cpu(es->s_lastcheck) +
679 			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
680 		ext2_msg(sb, KERN_WARNING,
681 			"warning: checktime reached, "
682 			"running e2fsck is recommended");
683 	if (!le16_to_cpu(es->s_max_mnt_count))
684 		es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
685 	le16_add_cpu(&es->s_mnt_count, 1);
686 	if (test_opt (sb, DEBUG))
687 		ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
688 			"bpg=%lu, ipg=%lu, mo=%04lx]",
689 			EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
690 			sbi->s_frag_size,
691 			sbi->s_groups_count,
692 			EXT2_BLOCKS_PER_GROUP(sb),
693 			EXT2_INODES_PER_GROUP(sb),
694 			sbi->s_mount_opt);
695 	return res;
696 }
697 
698 static int ext2_check_descriptors(struct super_block *sb)
699 {
700 	int i;
701 	struct ext2_sb_info *sbi = EXT2_SB(sb);
702 
703 	ext2_debug ("Checking group descriptors");
704 
705 	for (i = 0; i < sbi->s_groups_count; i++) {
706 		struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
707 		ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
708 		ext2_fsblk_t last_block;
709 
710 		if (i == sbi->s_groups_count - 1)
711 			last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
712 		else
713 			last_block = first_block +
714 				(EXT2_BLOCKS_PER_GROUP(sb) - 1);
715 
716 		if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
717 		    le32_to_cpu(gdp->bg_block_bitmap) > last_block)
718 		{
719 			ext2_error (sb, "ext2_check_descriptors",
720 				    "Block bitmap for group %d"
721 				    " not in group (block %lu)!",
722 				    i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
723 			return 0;
724 		}
725 		if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
726 		    le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
727 		{
728 			ext2_error (sb, "ext2_check_descriptors",
729 				    "Inode bitmap for group %d"
730 				    " not in group (block %lu)!",
731 				    i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
732 			return 0;
733 		}
734 		if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
735 		    le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
736 		    last_block)
737 		{
738 			ext2_error (sb, "ext2_check_descriptors",
739 				    "Inode table for group %d"
740 				    " not in group (block %lu)!",
741 				    i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
742 			return 0;
743 		}
744 	}
745 	return 1;
746 }
747 
748 /*
749  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
750  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
751  * We need to be 1 filesystem block less than the 2^32 sector limit.
752  */
753 static loff_t ext2_max_size(int bits)
754 {
755 	loff_t res = EXT2_NDIR_BLOCKS;
756 	int meta_blocks;
757 	loff_t upper_limit;
758 
759 	/* This is calculated to be the largest file size for a
760 	 * dense, file such that the total number of
761 	 * sectors in the file, including data and all indirect blocks,
762 	 * does not exceed 2^32 -1
763 	 * __u32 i_blocks representing the total number of
764 	 * 512 bytes blocks of the file
765 	 */
766 	upper_limit = (1LL << 32) - 1;
767 
768 	/* total blocks in file system block size */
769 	upper_limit >>= (bits - 9);
770 
771 
772 	/* indirect blocks */
773 	meta_blocks = 1;
774 	/* double indirect blocks */
775 	meta_blocks += 1 + (1LL << (bits-2));
776 	/* tripple indirect blocks */
777 	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
778 
779 	upper_limit -= meta_blocks;
780 	upper_limit <<= bits;
781 
782 	res += 1LL << (bits-2);
783 	res += 1LL << (2*(bits-2));
784 	res += 1LL << (3*(bits-2));
785 	res <<= bits;
786 	if (res > upper_limit)
787 		res = upper_limit;
788 
789 	if (res > MAX_LFS_FILESIZE)
790 		res = MAX_LFS_FILESIZE;
791 
792 	return res;
793 }
794 
795 static unsigned long descriptor_loc(struct super_block *sb,
796 				    unsigned long logic_sb_block,
797 				    int nr)
798 {
799 	struct ext2_sb_info *sbi = EXT2_SB(sb);
800 	unsigned long bg, first_meta_bg;
801 	int has_super = 0;
802 
803 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
804 
805 	if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
806 	    nr < first_meta_bg)
807 		return (logic_sb_block + nr + 1);
808 	bg = sbi->s_desc_per_block * nr;
809 	if (ext2_bg_has_super(sb, bg))
810 		has_super = 1;
811 
812 	return ext2_group_first_block_no(sb, bg) + has_super;
813 }
814 
815 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
816 {
817 	struct dax_device *dax_dev = fs_dax_get_by_bdev(sb->s_bdev);
818 	struct buffer_head * bh;
819 	struct ext2_sb_info * sbi;
820 	struct ext2_super_block * es;
821 	struct inode *root;
822 	unsigned long block;
823 	unsigned long sb_block = get_sb_block(&data);
824 	unsigned long logic_sb_block;
825 	unsigned long offset = 0;
826 	unsigned long def_mount_opts;
827 	long ret = -EINVAL;
828 	int blocksize = BLOCK_SIZE;
829 	int db_count;
830 	int i, j;
831 	__le32 features;
832 	int err;
833 	struct ext2_mount_options opts;
834 
835 	err = -ENOMEM;
836 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
837 	if (!sbi)
838 		goto failed;
839 
840 	sbi->s_blockgroup_lock =
841 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
842 	if (!sbi->s_blockgroup_lock) {
843 		kfree(sbi);
844 		goto failed;
845 	}
846 	sb->s_fs_info = sbi;
847 	sbi->s_sb_block = sb_block;
848 	sbi->s_daxdev = dax_dev;
849 
850 	spin_lock_init(&sbi->s_lock);
851 
852 	/*
853 	 * See what the current blocksize for the device is, and
854 	 * use that as the blocksize.  Otherwise (or if the blocksize
855 	 * is smaller than the default) use the default.
856 	 * This is important for devices that have a hardware
857 	 * sectorsize that is larger than the default.
858 	 */
859 	blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
860 	if (!blocksize) {
861 		ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
862 		goto failed_sbi;
863 	}
864 
865 	/*
866 	 * If the superblock doesn't start on a hardware sector boundary,
867 	 * calculate the offset.
868 	 */
869 	if (blocksize != BLOCK_SIZE) {
870 		logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
871 		offset = (sb_block*BLOCK_SIZE) % blocksize;
872 	} else {
873 		logic_sb_block = sb_block;
874 	}
875 
876 	if (!(bh = sb_bread(sb, logic_sb_block))) {
877 		ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
878 		goto failed_sbi;
879 	}
880 	/*
881 	 * Note: s_es must be initialized as soon as possible because
882 	 *       some ext2 macro-instructions depend on its value
883 	 */
884 	es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
885 	sbi->s_es = es;
886 	sb->s_magic = le16_to_cpu(es->s_magic);
887 
888 	if (sb->s_magic != EXT2_SUPER_MAGIC)
889 		goto cantfind_ext2;
890 
891 	/* Set defaults before we parse the mount options */
892 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
893 	if (def_mount_opts & EXT2_DEFM_DEBUG)
894 		set_opt(opts.s_mount_opt, DEBUG);
895 	if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
896 		set_opt(opts.s_mount_opt, GRPID);
897 	if (def_mount_opts & EXT2_DEFM_UID16)
898 		set_opt(opts.s_mount_opt, NO_UID32);
899 #ifdef CONFIG_EXT2_FS_XATTR
900 	if (def_mount_opts & EXT2_DEFM_XATTR_USER)
901 		set_opt(opts.s_mount_opt, XATTR_USER);
902 #endif
903 #ifdef CONFIG_EXT2_FS_POSIX_ACL
904 	if (def_mount_opts & EXT2_DEFM_ACL)
905 		set_opt(opts.s_mount_opt, POSIX_ACL);
906 #endif
907 
908 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
909 		set_opt(opts.s_mount_opt, ERRORS_PANIC);
910 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
911 		set_opt(opts.s_mount_opt, ERRORS_CONT);
912 	else
913 		set_opt(opts.s_mount_opt, ERRORS_RO);
914 
915 	opts.s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
916 	opts.s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
917 
918 	set_opt(opts.s_mount_opt, RESERVATION);
919 
920 	if (!parse_options((char *) data, sb, &opts))
921 		goto failed_mount;
922 
923 	sbi->s_mount_opt = opts.s_mount_opt;
924 	sbi->s_resuid = opts.s_resuid;
925 	sbi->s_resgid = opts.s_resgid;
926 
927 	sb->s_flags = (sb->s_flags & ~SB_POSIXACL) |
928 		((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
929 		 SB_POSIXACL : 0);
930 	sb->s_iflags |= SB_I_CGROUPWB;
931 
932 	if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
933 	    (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
934 	     EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
935 	     EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
936 		ext2_msg(sb, KERN_WARNING,
937 			"warning: feature flags set on rev 0 fs, "
938 			"running e2fsck is recommended");
939 	/*
940 	 * Check feature flags regardless of the revision level, since we
941 	 * previously didn't change the revision level when setting the flags,
942 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
943 	 */
944 	features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
945 	if (features) {
946 		ext2_msg(sb, KERN_ERR,	"error: couldn't mount because of "
947 		       "unsupported optional features (%x)",
948 			le32_to_cpu(features));
949 		goto failed_mount;
950 	}
951 	if (!sb_rdonly(sb) && (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
952 		ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
953 		       "unsupported optional features (%x)",
954 		       le32_to_cpu(features));
955 		goto failed_mount;
956 	}
957 
958 	blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
959 
960 	if (sbi->s_mount_opt & EXT2_MOUNT_DAX) {
961 		err = bdev_dax_supported(sb, blocksize);
962 		if (err)
963 			goto failed_mount;
964 	}
965 
966 	/* If the blocksize doesn't match, re-read the thing.. */
967 	if (sb->s_blocksize != blocksize) {
968 		brelse(bh);
969 
970 		if (!sb_set_blocksize(sb, blocksize)) {
971 			ext2_msg(sb, KERN_ERR,
972 				"error: bad blocksize %d", blocksize);
973 			goto failed_sbi;
974 		}
975 
976 		logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
977 		offset = (sb_block*BLOCK_SIZE) % blocksize;
978 		bh = sb_bread(sb, logic_sb_block);
979 		if(!bh) {
980 			ext2_msg(sb, KERN_ERR, "error: couldn't read"
981 				"superblock on 2nd try");
982 			goto failed_sbi;
983 		}
984 		es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
985 		sbi->s_es = es;
986 		if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
987 			ext2_msg(sb, KERN_ERR, "error: magic mismatch");
988 			goto failed_mount;
989 		}
990 	}
991 
992 	sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
993 	sb->s_max_links = EXT2_LINK_MAX;
994 
995 	if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
996 		sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
997 		sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
998 	} else {
999 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
1000 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
1001 		if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
1002 		    !is_power_of_2(sbi->s_inode_size) ||
1003 		    (sbi->s_inode_size > blocksize)) {
1004 			ext2_msg(sb, KERN_ERR,
1005 				"error: unsupported inode size: %d",
1006 				sbi->s_inode_size);
1007 			goto failed_mount;
1008 		}
1009 	}
1010 
1011 	sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
1012 				   le32_to_cpu(es->s_log_frag_size);
1013 	if (sbi->s_frag_size == 0)
1014 		goto cantfind_ext2;
1015 	sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
1016 
1017 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
1018 	sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
1019 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
1020 
1021 	if (EXT2_INODE_SIZE(sb) == 0)
1022 		goto cantfind_ext2;
1023 	sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
1024 	if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
1025 		goto cantfind_ext2;
1026 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
1027 					sbi->s_inodes_per_block;
1028 	sbi->s_desc_per_block = sb->s_blocksize /
1029 					sizeof (struct ext2_group_desc);
1030 	sbi->s_sbh = bh;
1031 	sbi->s_mount_state = le16_to_cpu(es->s_state);
1032 	sbi->s_addr_per_block_bits =
1033 		ilog2 (EXT2_ADDR_PER_BLOCK(sb));
1034 	sbi->s_desc_per_block_bits =
1035 		ilog2 (EXT2_DESC_PER_BLOCK(sb));
1036 
1037 	if (sb->s_magic != EXT2_SUPER_MAGIC)
1038 		goto cantfind_ext2;
1039 
1040 	if (sb->s_blocksize != bh->b_size) {
1041 		if (!silent)
1042 			ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
1043 		goto failed_mount;
1044 	}
1045 
1046 	if (sb->s_blocksize != sbi->s_frag_size) {
1047 		ext2_msg(sb, KERN_ERR,
1048 			"error: fragsize %lu != blocksize %lu"
1049 			"(not supported yet)",
1050 			sbi->s_frag_size, sb->s_blocksize);
1051 		goto failed_mount;
1052 	}
1053 
1054 	if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
1055 		ext2_msg(sb, KERN_ERR,
1056 			"error: #blocks per group too big: %lu",
1057 			sbi->s_blocks_per_group);
1058 		goto failed_mount;
1059 	}
1060 	if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
1061 		ext2_msg(sb, KERN_ERR,
1062 			"error: #fragments per group too big: %lu",
1063 			sbi->s_frags_per_group);
1064 		goto failed_mount;
1065 	}
1066 	if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
1067 		ext2_msg(sb, KERN_ERR,
1068 			"error: #inodes per group too big: %lu",
1069 			sbi->s_inodes_per_group);
1070 		goto failed_mount;
1071 	}
1072 
1073 	if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
1074 		goto cantfind_ext2;
1075  	sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
1076  				le32_to_cpu(es->s_first_data_block) - 1)
1077  					/ EXT2_BLOCKS_PER_GROUP(sb)) + 1;
1078 	db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
1079 		   EXT2_DESC_PER_BLOCK(sb);
1080 	sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
1081 	if (sbi->s_group_desc == NULL) {
1082 		ext2_msg(sb, KERN_ERR, "error: not enough memory");
1083 		goto failed_mount;
1084 	}
1085 	bgl_lock_init(sbi->s_blockgroup_lock);
1086 	sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1087 	if (!sbi->s_debts) {
1088 		ext2_msg(sb, KERN_ERR, "error: not enough memory");
1089 		goto failed_mount_group_desc;
1090 	}
1091 	for (i = 0; i < db_count; i++) {
1092 		block = descriptor_loc(sb, logic_sb_block, i);
1093 		sbi->s_group_desc[i] = sb_bread(sb, block);
1094 		if (!sbi->s_group_desc[i]) {
1095 			for (j = 0; j < i; j++)
1096 				brelse (sbi->s_group_desc[j]);
1097 			ext2_msg(sb, KERN_ERR,
1098 				"error: unable to read group descriptors");
1099 			goto failed_mount_group_desc;
1100 		}
1101 	}
1102 	if (!ext2_check_descriptors (sb)) {
1103 		ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1104 		goto failed_mount2;
1105 	}
1106 	sbi->s_gdb_count = db_count;
1107 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1108 	spin_lock_init(&sbi->s_next_gen_lock);
1109 
1110 	/* per fileystem reservation list head & lock */
1111 	spin_lock_init(&sbi->s_rsv_window_lock);
1112 	sbi->s_rsv_window_root = RB_ROOT;
1113 	/*
1114 	 * Add a single, static dummy reservation to the start of the
1115 	 * reservation window list --- it gives us a placeholder for
1116 	 * append-at-start-of-list which makes the allocation logic
1117 	 * _much_ simpler.
1118 	 */
1119 	sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1120 	sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1121 	sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1122 	sbi->s_rsv_window_head.rsv_goal_size = 0;
1123 	ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1124 
1125 	err = percpu_counter_init(&sbi->s_freeblocks_counter,
1126 				ext2_count_free_blocks(sb), GFP_KERNEL);
1127 	if (!err) {
1128 		err = percpu_counter_init(&sbi->s_freeinodes_counter,
1129 				ext2_count_free_inodes(sb), GFP_KERNEL);
1130 	}
1131 	if (!err) {
1132 		err = percpu_counter_init(&sbi->s_dirs_counter,
1133 				ext2_count_dirs(sb), GFP_KERNEL);
1134 	}
1135 	if (err) {
1136 		ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1137 		goto failed_mount3;
1138 	}
1139 
1140 #ifdef CONFIG_EXT2_FS_XATTR
1141 	sbi->s_ea_block_cache = ext2_xattr_create_cache();
1142 	if (!sbi->s_ea_block_cache) {
1143 		ext2_msg(sb, KERN_ERR, "Failed to create ea_block_cache");
1144 		goto failed_mount3;
1145 	}
1146 #endif
1147 	/*
1148 	 * set up enough so that it can read an inode
1149 	 */
1150 	sb->s_op = &ext2_sops;
1151 	sb->s_export_op = &ext2_export_ops;
1152 	sb->s_xattr = ext2_xattr_handlers;
1153 
1154 #ifdef CONFIG_QUOTA
1155 	sb->dq_op = &dquot_operations;
1156 	sb->s_qcop = &ext2_quotactl_ops;
1157 	sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP;
1158 #endif
1159 
1160 	root = ext2_iget(sb, EXT2_ROOT_INO);
1161 	if (IS_ERR(root)) {
1162 		ret = PTR_ERR(root);
1163 		goto failed_mount3;
1164 	}
1165 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1166 		iput(root);
1167 		ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1168 		goto failed_mount3;
1169 	}
1170 
1171 	sb->s_root = d_make_root(root);
1172 	if (!sb->s_root) {
1173 		ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1174 		ret = -ENOMEM;
1175 		goto failed_mount3;
1176 	}
1177 	if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1178 		ext2_msg(sb, KERN_WARNING,
1179 			"warning: mounting ext3 filesystem as ext2");
1180 	if (ext2_setup_super (sb, es, sb_rdonly(sb)))
1181 		sb->s_flags |= SB_RDONLY;
1182 	ext2_write_super(sb);
1183 	return 0;
1184 
1185 cantfind_ext2:
1186 	if (!silent)
1187 		ext2_msg(sb, KERN_ERR,
1188 			"error: can't find an ext2 filesystem on dev %s.",
1189 			sb->s_id);
1190 	goto failed_mount;
1191 failed_mount3:
1192 	if (sbi->s_ea_block_cache)
1193 		ext2_xattr_destroy_cache(sbi->s_ea_block_cache);
1194 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
1195 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
1196 	percpu_counter_destroy(&sbi->s_dirs_counter);
1197 failed_mount2:
1198 	for (i = 0; i < db_count; i++)
1199 		brelse(sbi->s_group_desc[i]);
1200 failed_mount_group_desc:
1201 	kfree(sbi->s_group_desc);
1202 	kfree(sbi->s_debts);
1203 failed_mount:
1204 	brelse(bh);
1205 failed_sbi:
1206 	sb->s_fs_info = NULL;
1207 	kfree(sbi->s_blockgroup_lock);
1208 	kfree(sbi);
1209 failed:
1210 	fs_put_dax(dax_dev);
1211 	return ret;
1212 }
1213 
1214 static void ext2_clear_super_error(struct super_block *sb)
1215 {
1216 	struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1217 
1218 	if (buffer_write_io_error(sbh)) {
1219 		/*
1220 		 * Oh, dear.  A previous attempt to write the
1221 		 * superblock failed.  This could happen because the
1222 		 * USB device was yanked out.  Or it could happen to
1223 		 * be a transient write error and maybe the block will
1224 		 * be remapped.  Nothing we can do but to retry the
1225 		 * write and hope for the best.
1226 		 */
1227 		ext2_msg(sb, KERN_ERR,
1228 		       "previous I/O error to superblock detected\n");
1229 		clear_buffer_write_io_error(sbh);
1230 		set_buffer_uptodate(sbh);
1231 	}
1232 }
1233 
1234 void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1235 		     int wait)
1236 {
1237 	ext2_clear_super_error(sb);
1238 	spin_lock(&EXT2_SB(sb)->s_lock);
1239 	es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1240 	es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1241 	es->s_wtime = cpu_to_le32(get_seconds());
1242 	/* unlock before we do IO */
1243 	spin_unlock(&EXT2_SB(sb)->s_lock);
1244 	mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1245 	if (wait)
1246 		sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1247 }
1248 
1249 /*
1250  * In the second extended file system, it is not necessary to
1251  * write the super block since we use a mapping of the
1252  * disk super block in a buffer.
1253  *
1254  * However, this function is still used to set the fs valid
1255  * flags to 0.  We need to set this flag to 0 since the fs
1256  * may have been checked while mounted and e2fsck may have
1257  * set s_state to EXT2_VALID_FS after some corrections.
1258  */
1259 static int ext2_sync_fs(struct super_block *sb, int wait)
1260 {
1261 	struct ext2_sb_info *sbi = EXT2_SB(sb);
1262 	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1263 
1264 	/*
1265 	 * Write quota structures to quota file, sync_blockdev() will write
1266 	 * them to disk later
1267 	 */
1268 	dquot_writeback_dquots(sb, -1);
1269 
1270 	spin_lock(&sbi->s_lock);
1271 	if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1272 		ext2_debug("setting valid to 0\n");
1273 		es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1274 	}
1275 	spin_unlock(&sbi->s_lock);
1276 	ext2_sync_super(sb, es, wait);
1277 	return 0;
1278 }
1279 
1280 static int ext2_freeze(struct super_block *sb)
1281 {
1282 	struct ext2_sb_info *sbi = EXT2_SB(sb);
1283 
1284 	/*
1285 	 * Open but unlinked files present? Keep EXT2_VALID_FS flag cleared
1286 	 * because we have unattached inodes and thus filesystem is not fully
1287 	 * consistent.
1288 	 */
1289 	if (atomic_long_read(&sb->s_remove_count)) {
1290 		ext2_sync_fs(sb, 1);
1291 		return 0;
1292 	}
1293 	/* Set EXT2_FS_VALID flag */
1294 	spin_lock(&sbi->s_lock);
1295 	sbi->s_es->s_state = cpu_to_le16(sbi->s_mount_state);
1296 	spin_unlock(&sbi->s_lock);
1297 	ext2_sync_super(sb, sbi->s_es, 1);
1298 
1299 	return 0;
1300 }
1301 
1302 static int ext2_unfreeze(struct super_block *sb)
1303 {
1304 	/* Just write sb to clear EXT2_VALID_FS flag */
1305 	ext2_write_super(sb);
1306 
1307 	return 0;
1308 }
1309 
1310 static void ext2_write_super(struct super_block *sb)
1311 {
1312 	if (!sb_rdonly(sb))
1313 		ext2_sync_fs(sb, 1);
1314 }
1315 
1316 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1317 {
1318 	struct ext2_sb_info * sbi = EXT2_SB(sb);
1319 	struct ext2_super_block * es;
1320 	struct ext2_mount_options new_opts;
1321 	int err;
1322 
1323 	sync_filesystem(sb);
1324 
1325 	spin_lock(&sbi->s_lock);
1326 	new_opts.s_mount_opt = sbi->s_mount_opt;
1327 	new_opts.s_resuid = sbi->s_resuid;
1328 	new_opts.s_resgid = sbi->s_resgid;
1329 	spin_unlock(&sbi->s_lock);
1330 
1331 	/*
1332 	 * Allow the "check" option to be passed as a remount option.
1333 	 */
1334 	if (!parse_options(data, sb, &new_opts))
1335 		return -EINVAL;
1336 
1337 	spin_lock(&sbi->s_lock);
1338 	es = sbi->s_es;
1339 	if ((sbi->s_mount_opt ^ new_opts.s_mount_opt) & EXT2_MOUNT_DAX) {
1340 		ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1341 			 "dax flag with busy inodes while remounting");
1342 		new_opts.s_mount_opt ^= EXT2_MOUNT_DAX;
1343 	}
1344 	if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1345 		goto out_set;
1346 	if (*flags & SB_RDONLY) {
1347 		if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1348 		    !(sbi->s_mount_state & EXT2_VALID_FS))
1349 			goto out_set;
1350 
1351 		/*
1352 		 * OK, we are remounting a valid rw partition rdonly, so set
1353 		 * the rdonly flag and then mark the partition as valid again.
1354 		 */
1355 		es->s_state = cpu_to_le16(sbi->s_mount_state);
1356 		es->s_mtime = cpu_to_le32(get_seconds());
1357 		spin_unlock(&sbi->s_lock);
1358 
1359 		err = dquot_suspend(sb, -1);
1360 		if (err < 0)
1361 			return err;
1362 
1363 		ext2_sync_super(sb, es, 1);
1364 	} else {
1365 		__le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1366 					       ~EXT2_FEATURE_RO_COMPAT_SUPP);
1367 		if (ret) {
1368 			spin_unlock(&sbi->s_lock);
1369 			ext2_msg(sb, KERN_WARNING,
1370 				"warning: couldn't remount RDWR because of "
1371 				"unsupported optional features (%x).",
1372 				le32_to_cpu(ret));
1373 			return -EROFS;
1374 		}
1375 		/*
1376 		 * Mounting a RDONLY partition read-write, so reread and
1377 		 * store the current valid flag.  (It may have been changed
1378 		 * by e2fsck since we originally mounted the partition.)
1379 		 */
1380 		sbi->s_mount_state = le16_to_cpu(es->s_state);
1381 		if (!ext2_setup_super (sb, es, 0))
1382 			sb->s_flags &= ~SB_RDONLY;
1383 		spin_unlock(&sbi->s_lock);
1384 
1385 		ext2_write_super(sb);
1386 
1387 		dquot_resume(sb, -1);
1388 	}
1389 
1390 	spin_lock(&sbi->s_lock);
1391 out_set:
1392 	sbi->s_mount_opt = new_opts.s_mount_opt;
1393 	sbi->s_resuid = new_opts.s_resuid;
1394 	sbi->s_resgid = new_opts.s_resgid;
1395 	sb->s_flags = (sb->s_flags & ~SB_POSIXACL) |
1396 		((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? SB_POSIXACL : 0);
1397 	spin_unlock(&sbi->s_lock);
1398 
1399 	return 0;
1400 }
1401 
1402 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1403 {
1404 	struct super_block *sb = dentry->d_sb;
1405 	struct ext2_sb_info *sbi = EXT2_SB(sb);
1406 	struct ext2_super_block *es = sbi->s_es;
1407 	u64 fsid;
1408 
1409 	spin_lock(&sbi->s_lock);
1410 
1411 	if (test_opt (sb, MINIX_DF))
1412 		sbi->s_overhead_last = 0;
1413 	else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1414 		unsigned long i, overhead = 0;
1415 		smp_rmb();
1416 
1417 		/*
1418 		 * Compute the overhead (FS structures). This is constant
1419 		 * for a given filesystem unless the number of block groups
1420 		 * changes so we cache the previous value until it does.
1421 		 */
1422 
1423 		/*
1424 		 * All of the blocks before first_data_block are
1425 		 * overhead
1426 		 */
1427 		overhead = le32_to_cpu(es->s_first_data_block);
1428 
1429 		/*
1430 		 * Add the overhead attributed to the superblock and
1431 		 * block group descriptors.  If the sparse superblocks
1432 		 * feature is turned on, then not all groups have this.
1433 		 */
1434 		for (i = 0; i < sbi->s_groups_count; i++)
1435 			overhead += ext2_bg_has_super(sb, i) +
1436 				ext2_bg_num_gdb(sb, i);
1437 
1438 		/*
1439 		 * Every block group has an inode bitmap, a block
1440 		 * bitmap, and an inode table.
1441 		 */
1442 		overhead += (sbi->s_groups_count *
1443 			     (2 + sbi->s_itb_per_group));
1444 		sbi->s_overhead_last = overhead;
1445 		smp_wmb();
1446 		sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1447 	}
1448 
1449 	buf->f_type = EXT2_SUPER_MAGIC;
1450 	buf->f_bsize = sb->s_blocksize;
1451 	buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1452 	buf->f_bfree = ext2_count_free_blocks(sb);
1453 	es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1454 	buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1455 	if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1456 		buf->f_bavail = 0;
1457 	buf->f_files = le32_to_cpu(es->s_inodes_count);
1458 	buf->f_ffree = ext2_count_free_inodes(sb);
1459 	es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1460 	buf->f_namelen = EXT2_NAME_LEN;
1461 	fsid = le64_to_cpup((void *)es->s_uuid) ^
1462 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1463 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1464 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1465 	spin_unlock(&sbi->s_lock);
1466 	return 0;
1467 }
1468 
1469 static struct dentry *ext2_mount(struct file_system_type *fs_type,
1470 	int flags, const char *dev_name, void *data)
1471 {
1472 	return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1473 }
1474 
1475 #ifdef CONFIG_QUOTA
1476 
1477 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1478  * acquiring the locks... As quota files are never truncated and quota code
1479  * itself serializes the operations (and no one else should touch the files)
1480  * we don't have to be afraid of races */
1481 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1482 			       size_t len, loff_t off)
1483 {
1484 	struct inode *inode = sb_dqopt(sb)->files[type];
1485 	sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1486 	int err = 0;
1487 	int offset = off & (sb->s_blocksize - 1);
1488 	int tocopy;
1489 	size_t toread;
1490 	struct buffer_head tmp_bh;
1491 	struct buffer_head *bh;
1492 	loff_t i_size = i_size_read(inode);
1493 
1494 	if (off > i_size)
1495 		return 0;
1496 	if (off+len > i_size)
1497 		len = i_size-off;
1498 	toread = len;
1499 	while (toread > 0) {
1500 		tocopy = sb->s_blocksize - offset < toread ?
1501 				sb->s_blocksize - offset : toread;
1502 
1503 		tmp_bh.b_state = 0;
1504 		tmp_bh.b_size = sb->s_blocksize;
1505 		err = ext2_get_block(inode, blk, &tmp_bh, 0);
1506 		if (err < 0)
1507 			return err;
1508 		if (!buffer_mapped(&tmp_bh))	/* A hole? */
1509 			memset(data, 0, tocopy);
1510 		else {
1511 			bh = sb_bread(sb, tmp_bh.b_blocknr);
1512 			if (!bh)
1513 				return -EIO;
1514 			memcpy(data, bh->b_data+offset, tocopy);
1515 			brelse(bh);
1516 		}
1517 		offset = 0;
1518 		toread -= tocopy;
1519 		data += tocopy;
1520 		blk++;
1521 	}
1522 	return len;
1523 }
1524 
1525 /* Write to quotafile */
1526 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1527 				const char *data, size_t len, loff_t off)
1528 {
1529 	struct inode *inode = sb_dqopt(sb)->files[type];
1530 	sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1531 	int err = 0;
1532 	int offset = off & (sb->s_blocksize - 1);
1533 	int tocopy;
1534 	size_t towrite = len;
1535 	struct buffer_head tmp_bh;
1536 	struct buffer_head *bh;
1537 
1538 	while (towrite > 0) {
1539 		tocopy = sb->s_blocksize - offset < towrite ?
1540 				sb->s_blocksize - offset : towrite;
1541 
1542 		tmp_bh.b_state = 0;
1543 		tmp_bh.b_size = sb->s_blocksize;
1544 		err = ext2_get_block(inode, blk, &tmp_bh, 1);
1545 		if (err < 0)
1546 			goto out;
1547 		if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1548 			bh = sb_bread(sb, tmp_bh.b_blocknr);
1549 		else
1550 			bh = sb_getblk(sb, tmp_bh.b_blocknr);
1551 		if (unlikely(!bh)) {
1552 			err = -EIO;
1553 			goto out;
1554 		}
1555 		lock_buffer(bh);
1556 		memcpy(bh->b_data+offset, data, tocopy);
1557 		flush_dcache_page(bh->b_page);
1558 		set_buffer_uptodate(bh);
1559 		mark_buffer_dirty(bh);
1560 		unlock_buffer(bh);
1561 		brelse(bh);
1562 		offset = 0;
1563 		towrite -= tocopy;
1564 		data += tocopy;
1565 		blk++;
1566 	}
1567 out:
1568 	if (len == towrite)
1569 		return err;
1570 	if (inode->i_size < off+len-towrite)
1571 		i_size_write(inode, off+len-towrite);
1572 	inode->i_version++;
1573 	inode->i_mtime = inode->i_ctime = current_time(inode);
1574 	mark_inode_dirty(inode);
1575 	return len - towrite;
1576 }
1577 
1578 static int ext2_quota_on(struct super_block *sb, int type, int format_id,
1579 			 const struct path *path)
1580 {
1581 	int err;
1582 	struct inode *inode;
1583 
1584 	err = dquot_quota_on(sb, type, format_id, path);
1585 	if (err)
1586 		return err;
1587 
1588 	inode = d_inode(path->dentry);
1589 	inode_lock(inode);
1590 	EXT2_I(inode)->i_flags |= EXT2_NOATIME_FL | EXT2_IMMUTABLE_FL;
1591 	inode_set_flags(inode, S_NOATIME | S_IMMUTABLE,
1592 			S_NOATIME | S_IMMUTABLE);
1593 	inode_unlock(inode);
1594 	mark_inode_dirty(inode);
1595 
1596 	return 0;
1597 }
1598 
1599 static int ext2_quota_off(struct super_block *sb, int type)
1600 {
1601 	struct inode *inode = sb_dqopt(sb)->files[type];
1602 	int err;
1603 
1604 	if (!inode || !igrab(inode))
1605 		goto out;
1606 
1607 	err = dquot_quota_off(sb, type);
1608 	if (err)
1609 		goto out_put;
1610 
1611 	inode_lock(inode);
1612 	EXT2_I(inode)->i_flags &= ~(EXT2_NOATIME_FL | EXT2_IMMUTABLE_FL);
1613 	inode_set_flags(inode, 0, S_NOATIME | S_IMMUTABLE);
1614 	inode_unlock(inode);
1615 	mark_inode_dirty(inode);
1616 out_put:
1617 	iput(inode);
1618 	return err;
1619 out:
1620 	return dquot_quota_off(sb, type);
1621 }
1622 
1623 #endif
1624 
1625 static struct file_system_type ext2_fs_type = {
1626 	.owner		= THIS_MODULE,
1627 	.name		= "ext2",
1628 	.mount		= ext2_mount,
1629 	.kill_sb	= kill_block_super,
1630 	.fs_flags	= FS_REQUIRES_DEV,
1631 };
1632 MODULE_ALIAS_FS("ext2");
1633 
1634 static int __init init_ext2_fs(void)
1635 {
1636 	int err;
1637 
1638 	err = init_inodecache();
1639 	if (err)
1640 		return err;
1641         err = register_filesystem(&ext2_fs_type);
1642 	if (err)
1643 		goto out;
1644 	return 0;
1645 out:
1646 	destroy_inodecache();
1647 	return err;
1648 }
1649 
1650 static void __exit exit_ext2_fs(void)
1651 {
1652 	unregister_filesystem(&ext2_fs_type);
1653 	destroy_inodecache();
1654 }
1655 
1656 MODULE_AUTHOR("Remy Card and others");
1657 MODULE_DESCRIPTION("Second Extended Filesystem");
1658 MODULE_LICENSE("GPL");
1659 module_init(init_ext2_fs)
1660 module_exit(exit_ext2_fs)
1661