xref: /openbmc/linux/fs/ext4/super.c (revision 6c7c3245)
1 /*
2  *  linux/fs/ext4/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/time.h>
23 #include <linux/vmalloc.h>
24 #include <linux/slab.h>
25 #include <linux/init.h>
26 #include <linux/blkdev.h>
27 #include <linux/backing-dev.h>
28 #include <linux/parser.h>
29 #include <linux/buffer_head.h>
30 #include <linux/exportfs.h>
31 #include <linux/vfs.h>
32 #include <linux/random.h>
33 #include <linux/mount.h>
34 #include <linux/namei.h>
35 #include <linux/quotaops.h>
36 #include <linux/seq_file.h>
37 #include <linux/ctype.h>
38 #include <linux/log2.h>
39 #include <linux/crc16.h>
40 #include <linux/cleancache.h>
41 #include <asm/uaccess.h>
42 
43 #include <linux/kthread.h>
44 #include <linux/freezer.h>
45 
46 #include "ext4.h"
47 #include "ext4_extents.h"	/* Needed for trace points definition */
48 #include "ext4_jbd2.h"
49 #include "xattr.h"
50 #include "acl.h"
51 #include "mballoc.h"
52 
53 #define CREATE_TRACE_POINTS
54 #include <trace/events/ext4.h>
55 
56 static struct ext4_lazy_init *ext4_li_info;
57 static struct mutex ext4_li_mtx;
58 static struct ratelimit_state ext4_mount_msg_ratelimit;
59 
60 static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
61 			     unsigned long journal_devnum);
62 static int ext4_show_options(struct seq_file *seq, struct dentry *root);
63 static int ext4_commit_super(struct super_block *sb, int sync);
64 static void ext4_mark_recovery_complete(struct super_block *sb,
65 					struct ext4_super_block *es);
66 static void ext4_clear_journal_err(struct super_block *sb,
67 				   struct ext4_super_block *es);
68 static int ext4_sync_fs(struct super_block *sb, int wait);
69 static int ext4_remount(struct super_block *sb, int *flags, char *data);
70 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf);
71 static int ext4_unfreeze(struct super_block *sb);
72 static int ext4_freeze(struct super_block *sb);
73 static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
74 		       const char *dev_name, void *data);
75 static inline int ext2_feature_set_ok(struct super_block *sb);
76 static inline int ext3_feature_set_ok(struct super_block *sb);
77 static int ext4_feature_set_ok(struct super_block *sb, int readonly);
78 static void ext4_destroy_lazyinit_thread(void);
79 static void ext4_unregister_li_request(struct super_block *sb);
80 static void ext4_clear_request_list(void);
81 
82 /*
83  * Lock ordering
84  *
85  * Note the difference between i_mmap_sem (EXT4_I(inode)->i_mmap_sem) and
86  * i_mmap_rwsem (inode->i_mmap_rwsem)!
87  *
88  * page fault path:
89  * mmap_sem -> sb_start_pagefault -> i_mmap_sem (r) -> transaction start ->
90  *   page lock -> i_data_sem (rw)
91  *
92  * buffered write path:
93  * sb_start_write -> i_mutex -> mmap_sem
94  * sb_start_write -> i_mutex -> transaction start -> page lock ->
95  *   i_data_sem (rw)
96  *
97  * truncate:
98  * sb_start_write -> i_mutex -> EXT4_STATE_DIOREAD_LOCK (w) -> i_mmap_sem (w) ->
99  *   i_mmap_rwsem (w) -> page lock
100  * sb_start_write -> i_mutex -> EXT4_STATE_DIOREAD_LOCK (w) -> i_mmap_sem (w) ->
101  *   transaction start -> i_data_sem (rw)
102  *
103  * direct IO:
104  * sb_start_write -> i_mutex -> EXT4_STATE_DIOREAD_LOCK (r) -> mmap_sem
105  * sb_start_write -> i_mutex -> EXT4_STATE_DIOREAD_LOCK (r) ->
106  *   transaction start -> i_data_sem (rw)
107  *
108  * writepages:
109  * transaction start -> page lock(s) -> i_data_sem (rw)
110  */
111 
112 #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT2)
113 static struct file_system_type ext2_fs_type = {
114 	.owner		= THIS_MODULE,
115 	.name		= "ext2",
116 	.mount		= ext4_mount,
117 	.kill_sb	= kill_block_super,
118 	.fs_flags	= FS_REQUIRES_DEV,
119 };
120 MODULE_ALIAS_FS("ext2");
121 MODULE_ALIAS("ext2");
122 #define IS_EXT2_SB(sb) ((sb)->s_bdev->bd_holder == &ext2_fs_type)
123 #else
124 #define IS_EXT2_SB(sb) (0)
125 #endif
126 
127 
128 static struct file_system_type ext3_fs_type = {
129 	.owner		= THIS_MODULE,
130 	.name		= "ext3",
131 	.mount		= ext4_mount,
132 	.kill_sb	= kill_block_super,
133 	.fs_flags	= FS_REQUIRES_DEV,
134 };
135 MODULE_ALIAS_FS("ext3");
136 MODULE_ALIAS("ext3");
137 #define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type)
138 
139 static int ext4_verify_csum_type(struct super_block *sb,
140 				 struct ext4_super_block *es)
141 {
142 	if (!ext4_has_feature_metadata_csum(sb))
143 		return 1;
144 
145 	return es->s_checksum_type == EXT4_CRC32C_CHKSUM;
146 }
147 
148 static __le32 ext4_superblock_csum(struct super_block *sb,
149 				   struct ext4_super_block *es)
150 {
151 	struct ext4_sb_info *sbi = EXT4_SB(sb);
152 	int offset = offsetof(struct ext4_super_block, s_checksum);
153 	__u32 csum;
154 
155 	csum = ext4_chksum(sbi, ~0, (char *)es, offset);
156 
157 	return cpu_to_le32(csum);
158 }
159 
160 static int ext4_superblock_csum_verify(struct super_block *sb,
161 				       struct ext4_super_block *es)
162 {
163 	if (!ext4_has_metadata_csum(sb))
164 		return 1;
165 
166 	return es->s_checksum == ext4_superblock_csum(sb, es);
167 }
168 
169 void ext4_superblock_csum_set(struct super_block *sb)
170 {
171 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
172 
173 	if (!ext4_has_metadata_csum(sb))
174 		return;
175 
176 	es->s_checksum = ext4_superblock_csum(sb, es);
177 }
178 
179 void *ext4_kvmalloc(size_t size, gfp_t flags)
180 {
181 	void *ret;
182 
183 	ret = kmalloc(size, flags | __GFP_NOWARN);
184 	if (!ret)
185 		ret = __vmalloc(size, flags, PAGE_KERNEL);
186 	return ret;
187 }
188 
189 void *ext4_kvzalloc(size_t size, gfp_t flags)
190 {
191 	void *ret;
192 
193 	ret = kzalloc(size, flags | __GFP_NOWARN);
194 	if (!ret)
195 		ret = __vmalloc(size, flags | __GFP_ZERO, PAGE_KERNEL);
196 	return ret;
197 }
198 
199 ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
200 			       struct ext4_group_desc *bg)
201 {
202 	return le32_to_cpu(bg->bg_block_bitmap_lo) |
203 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
204 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_block_bitmap_hi) << 32 : 0);
205 }
206 
207 ext4_fsblk_t ext4_inode_bitmap(struct super_block *sb,
208 			       struct ext4_group_desc *bg)
209 {
210 	return le32_to_cpu(bg->bg_inode_bitmap_lo) |
211 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
212 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_bitmap_hi) << 32 : 0);
213 }
214 
215 ext4_fsblk_t ext4_inode_table(struct super_block *sb,
216 			      struct ext4_group_desc *bg)
217 {
218 	return le32_to_cpu(bg->bg_inode_table_lo) |
219 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
220 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_table_hi) << 32 : 0);
221 }
222 
223 __u32 ext4_free_group_clusters(struct super_block *sb,
224 			       struct ext4_group_desc *bg)
225 {
226 	return le16_to_cpu(bg->bg_free_blocks_count_lo) |
227 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
228 		 (__u32)le16_to_cpu(bg->bg_free_blocks_count_hi) << 16 : 0);
229 }
230 
231 __u32 ext4_free_inodes_count(struct super_block *sb,
232 			      struct ext4_group_desc *bg)
233 {
234 	return le16_to_cpu(bg->bg_free_inodes_count_lo) |
235 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
236 		 (__u32)le16_to_cpu(bg->bg_free_inodes_count_hi) << 16 : 0);
237 }
238 
239 __u32 ext4_used_dirs_count(struct super_block *sb,
240 			      struct ext4_group_desc *bg)
241 {
242 	return le16_to_cpu(bg->bg_used_dirs_count_lo) |
243 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
244 		 (__u32)le16_to_cpu(bg->bg_used_dirs_count_hi) << 16 : 0);
245 }
246 
247 __u32 ext4_itable_unused_count(struct super_block *sb,
248 			      struct ext4_group_desc *bg)
249 {
250 	return le16_to_cpu(bg->bg_itable_unused_lo) |
251 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
252 		 (__u32)le16_to_cpu(bg->bg_itable_unused_hi) << 16 : 0);
253 }
254 
255 void ext4_block_bitmap_set(struct super_block *sb,
256 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
257 {
258 	bg->bg_block_bitmap_lo = cpu_to_le32((u32)blk);
259 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
260 		bg->bg_block_bitmap_hi = cpu_to_le32(blk >> 32);
261 }
262 
263 void ext4_inode_bitmap_set(struct super_block *sb,
264 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
265 {
266 	bg->bg_inode_bitmap_lo  = cpu_to_le32((u32)blk);
267 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
268 		bg->bg_inode_bitmap_hi = cpu_to_le32(blk >> 32);
269 }
270 
271 void ext4_inode_table_set(struct super_block *sb,
272 			  struct ext4_group_desc *bg, ext4_fsblk_t blk)
273 {
274 	bg->bg_inode_table_lo = cpu_to_le32((u32)blk);
275 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
276 		bg->bg_inode_table_hi = cpu_to_le32(blk >> 32);
277 }
278 
279 void ext4_free_group_clusters_set(struct super_block *sb,
280 				  struct ext4_group_desc *bg, __u32 count)
281 {
282 	bg->bg_free_blocks_count_lo = cpu_to_le16((__u16)count);
283 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
284 		bg->bg_free_blocks_count_hi = cpu_to_le16(count >> 16);
285 }
286 
287 void ext4_free_inodes_set(struct super_block *sb,
288 			  struct ext4_group_desc *bg, __u32 count)
289 {
290 	bg->bg_free_inodes_count_lo = cpu_to_le16((__u16)count);
291 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
292 		bg->bg_free_inodes_count_hi = cpu_to_le16(count >> 16);
293 }
294 
295 void ext4_used_dirs_set(struct super_block *sb,
296 			  struct ext4_group_desc *bg, __u32 count)
297 {
298 	bg->bg_used_dirs_count_lo = cpu_to_le16((__u16)count);
299 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
300 		bg->bg_used_dirs_count_hi = cpu_to_le16(count >> 16);
301 }
302 
303 void ext4_itable_unused_set(struct super_block *sb,
304 			  struct ext4_group_desc *bg, __u32 count)
305 {
306 	bg->bg_itable_unused_lo = cpu_to_le16((__u16)count);
307 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
308 		bg->bg_itable_unused_hi = cpu_to_le16(count >> 16);
309 }
310 
311 
312 static void __save_error_info(struct super_block *sb, const char *func,
313 			    unsigned int line)
314 {
315 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
316 
317 	EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
318 	if (bdev_read_only(sb->s_bdev))
319 		return;
320 	es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
321 	es->s_last_error_time = cpu_to_le32(get_seconds());
322 	strncpy(es->s_last_error_func, func, sizeof(es->s_last_error_func));
323 	es->s_last_error_line = cpu_to_le32(line);
324 	if (!es->s_first_error_time) {
325 		es->s_first_error_time = es->s_last_error_time;
326 		strncpy(es->s_first_error_func, func,
327 			sizeof(es->s_first_error_func));
328 		es->s_first_error_line = cpu_to_le32(line);
329 		es->s_first_error_ino = es->s_last_error_ino;
330 		es->s_first_error_block = es->s_last_error_block;
331 	}
332 	/*
333 	 * Start the daily error reporting function if it hasn't been
334 	 * started already
335 	 */
336 	if (!es->s_error_count)
337 		mod_timer(&EXT4_SB(sb)->s_err_report, jiffies + 24*60*60*HZ);
338 	le32_add_cpu(&es->s_error_count, 1);
339 }
340 
341 static void save_error_info(struct super_block *sb, const char *func,
342 			    unsigned int line)
343 {
344 	__save_error_info(sb, func, line);
345 	ext4_commit_super(sb, 1);
346 }
347 
348 /*
349  * The del_gendisk() function uninitializes the disk-specific data
350  * structures, including the bdi structure, without telling anyone
351  * else.  Once this happens, any attempt to call mark_buffer_dirty()
352  * (for example, by ext4_commit_super), will cause a kernel OOPS.
353  * This is a kludge to prevent these oops until we can put in a proper
354  * hook in del_gendisk() to inform the VFS and file system layers.
355  */
356 static int block_device_ejected(struct super_block *sb)
357 {
358 	struct inode *bd_inode = sb->s_bdev->bd_inode;
359 	struct backing_dev_info *bdi = inode_to_bdi(bd_inode);
360 
361 	return bdi->dev == NULL;
362 }
363 
364 static void ext4_journal_commit_callback(journal_t *journal, transaction_t *txn)
365 {
366 	struct super_block		*sb = journal->j_private;
367 	struct ext4_sb_info		*sbi = EXT4_SB(sb);
368 	int				error = is_journal_aborted(journal);
369 	struct ext4_journal_cb_entry	*jce;
370 
371 	BUG_ON(txn->t_state == T_FINISHED);
372 	spin_lock(&sbi->s_md_lock);
373 	while (!list_empty(&txn->t_private_list)) {
374 		jce = list_entry(txn->t_private_list.next,
375 				 struct ext4_journal_cb_entry, jce_list);
376 		list_del_init(&jce->jce_list);
377 		spin_unlock(&sbi->s_md_lock);
378 		jce->jce_func(sb, jce, error);
379 		spin_lock(&sbi->s_md_lock);
380 	}
381 	spin_unlock(&sbi->s_md_lock);
382 }
383 
384 /* Deal with the reporting of failure conditions on a filesystem such as
385  * inconsistencies detected or read IO failures.
386  *
387  * On ext2, we can store the error state of the filesystem in the
388  * superblock.  That is not possible on ext4, because we may have other
389  * write ordering constraints on the superblock which prevent us from
390  * writing it out straight away; and given that the journal is about to
391  * be aborted, we can't rely on the current, or future, transactions to
392  * write out the superblock safely.
393  *
394  * We'll just use the jbd2_journal_abort() error code to record an error in
395  * the journal instead.  On recovery, the journal will complain about
396  * that error until we've noted it down and cleared it.
397  */
398 
399 static void ext4_handle_error(struct super_block *sb)
400 {
401 	if (sb->s_flags & MS_RDONLY)
402 		return;
403 
404 	if (!test_opt(sb, ERRORS_CONT)) {
405 		journal_t *journal = EXT4_SB(sb)->s_journal;
406 
407 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
408 		if (journal)
409 			jbd2_journal_abort(journal, -EIO);
410 	}
411 	if (test_opt(sb, ERRORS_RO)) {
412 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
413 		/*
414 		 * Make sure updated value of ->s_mount_flags will be visible
415 		 * before ->s_flags update
416 		 */
417 		smp_wmb();
418 		sb->s_flags |= MS_RDONLY;
419 	}
420 	if (test_opt(sb, ERRORS_PANIC)) {
421 		if (EXT4_SB(sb)->s_journal &&
422 		  !(EXT4_SB(sb)->s_journal->j_flags & JBD2_REC_ERR))
423 			return;
424 		panic("EXT4-fs (device %s): panic forced after error\n",
425 			sb->s_id);
426 	}
427 }
428 
429 #define ext4_error_ratelimit(sb)					\
430 		___ratelimit(&(EXT4_SB(sb)->s_err_ratelimit_state),	\
431 			     "EXT4-fs error")
432 
433 void __ext4_error(struct super_block *sb, const char *function,
434 		  unsigned int line, const char *fmt, ...)
435 {
436 	struct va_format vaf;
437 	va_list args;
438 
439 	if (ext4_error_ratelimit(sb)) {
440 		va_start(args, fmt);
441 		vaf.fmt = fmt;
442 		vaf.va = &args;
443 		printk(KERN_CRIT
444 		       "EXT4-fs error (device %s): %s:%d: comm %s: %pV\n",
445 		       sb->s_id, function, line, current->comm, &vaf);
446 		va_end(args);
447 	}
448 	save_error_info(sb, function, line);
449 	ext4_handle_error(sb);
450 }
451 
452 void __ext4_error_inode(struct inode *inode, const char *function,
453 			unsigned int line, ext4_fsblk_t block,
454 			const char *fmt, ...)
455 {
456 	va_list args;
457 	struct va_format vaf;
458 	struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
459 
460 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
461 	es->s_last_error_block = cpu_to_le64(block);
462 	if (ext4_error_ratelimit(inode->i_sb)) {
463 		va_start(args, fmt);
464 		vaf.fmt = fmt;
465 		vaf.va = &args;
466 		if (block)
467 			printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
468 			       "inode #%lu: block %llu: comm %s: %pV\n",
469 			       inode->i_sb->s_id, function, line, inode->i_ino,
470 			       block, current->comm, &vaf);
471 		else
472 			printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
473 			       "inode #%lu: comm %s: %pV\n",
474 			       inode->i_sb->s_id, function, line, inode->i_ino,
475 			       current->comm, &vaf);
476 		va_end(args);
477 	}
478 	save_error_info(inode->i_sb, function, line);
479 	ext4_handle_error(inode->i_sb);
480 }
481 
482 void __ext4_error_file(struct file *file, const char *function,
483 		       unsigned int line, ext4_fsblk_t block,
484 		       const char *fmt, ...)
485 {
486 	va_list args;
487 	struct va_format vaf;
488 	struct ext4_super_block *es;
489 	struct inode *inode = file_inode(file);
490 	char pathname[80], *path;
491 
492 	es = EXT4_SB(inode->i_sb)->s_es;
493 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
494 	if (ext4_error_ratelimit(inode->i_sb)) {
495 		path = file_path(file, pathname, sizeof(pathname));
496 		if (IS_ERR(path))
497 			path = "(unknown)";
498 		va_start(args, fmt);
499 		vaf.fmt = fmt;
500 		vaf.va = &args;
501 		if (block)
502 			printk(KERN_CRIT
503 			       "EXT4-fs error (device %s): %s:%d: inode #%lu: "
504 			       "block %llu: comm %s: path %s: %pV\n",
505 			       inode->i_sb->s_id, function, line, inode->i_ino,
506 			       block, current->comm, path, &vaf);
507 		else
508 			printk(KERN_CRIT
509 			       "EXT4-fs error (device %s): %s:%d: inode #%lu: "
510 			       "comm %s: path %s: %pV\n",
511 			       inode->i_sb->s_id, function, line, inode->i_ino,
512 			       current->comm, path, &vaf);
513 		va_end(args);
514 	}
515 	save_error_info(inode->i_sb, function, line);
516 	ext4_handle_error(inode->i_sb);
517 }
518 
519 const char *ext4_decode_error(struct super_block *sb, int errno,
520 			      char nbuf[16])
521 {
522 	char *errstr = NULL;
523 
524 	switch (errno) {
525 	case -EFSCORRUPTED:
526 		errstr = "Corrupt filesystem";
527 		break;
528 	case -EFSBADCRC:
529 		errstr = "Filesystem failed CRC";
530 		break;
531 	case -EIO:
532 		errstr = "IO failure";
533 		break;
534 	case -ENOMEM:
535 		errstr = "Out of memory";
536 		break;
537 	case -EROFS:
538 		if (!sb || (EXT4_SB(sb)->s_journal &&
539 			    EXT4_SB(sb)->s_journal->j_flags & JBD2_ABORT))
540 			errstr = "Journal has aborted";
541 		else
542 			errstr = "Readonly filesystem";
543 		break;
544 	default:
545 		/* If the caller passed in an extra buffer for unknown
546 		 * errors, textualise them now.  Else we just return
547 		 * NULL. */
548 		if (nbuf) {
549 			/* Check for truncated error codes... */
550 			if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
551 				errstr = nbuf;
552 		}
553 		break;
554 	}
555 
556 	return errstr;
557 }
558 
559 /* __ext4_std_error decodes expected errors from journaling functions
560  * automatically and invokes the appropriate error response.  */
561 
562 void __ext4_std_error(struct super_block *sb, const char *function,
563 		      unsigned int line, int errno)
564 {
565 	char nbuf[16];
566 	const char *errstr;
567 
568 	/* Special case: if the error is EROFS, and we're not already
569 	 * inside a transaction, then there's really no point in logging
570 	 * an error. */
571 	if (errno == -EROFS && journal_current_handle() == NULL &&
572 	    (sb->s_flags & MS_RDONLY))
573 		return;
574 
575 	if (ext4_error_ratelimit(sb)) {
576 		errstr = ext4_decode_error(sb, errno, nbuf);
577 		printk(KERN_CRIT "EXT4-fs error (device %s) in %s:%d: %s\n",
578 		       sb->s_id, function, line, errstr);
579 	}
580 
581 	save_error_info(sb, function, line);
582 	ext4_handle_error(sb);
583 }
584 
585 /*
586  * ext4_abort is a much stronger failure handler than ext4_error.  The
587  * abort function may be used to deal with unrecoverable failures such
588  * as journal IO errors or ENOMEM at a critical moment in log management.
589  *
590  * We unconditionally force the filesystem into an ABORT|READONLY state,
591  * unless the error response on the fs has been set to panic in which
592  * case we take the easy way out and panic immediately.
593  */
594 
595 void __ext4_abort(struct super_block *sb, const char *function,
596 		unsigned int line, const char *fmt, ...)
597 {
598 	va_list args;
599 
600 	save_error_info(sb, function, line);
601 	va_start(args, fmt);
602 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: ", sb->s_id,
603 	       function, line);
604 	vprintk(fmt, args);
605 	printk("\n");
606 	va_end(args);
607 
608 	if ((sb->s_flags & MS_RDONLY) == 0) {
609 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
610 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
611 		/*
612 		 * Make sure updated value of ->s_mount_flags will be visible
613 		 * before ->s_flags update
614 		 */
615 		smp_wmb();
616 		sb->s_flags |= MS_RDONLY;
617 		if (EXT4_SB(sb)->s_journal)
618 			jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
619 		save_error_info(sb, function, line);
620 	}
621 	if (test_opt(sb, ERRORS_PANIC)) {
622 		if (EXT4_SB(sb)->s_journal &&
623 		  !(EXT4_SB(sb)->s_journal->j_flags & JBD2_REC_ERR))
624 			return;
625 		panic("EXT4-fs panic from previous error\n");
626 	}
627 }
628 
629 void __ext4_msg(struct super_block *sb,
630 		const char *prefix, const char *fmt, ...)
631 {
632 	struct va_format vaf;
633 	va_list args;
634 
635 	if (!___ratelimit(&(EXT4_SB(sb)->s_msg_ratelimit_state), "EXT4-fs"))
636 		return;
637 
638 	va_start(args, fmt);
639 	vaf.fmt = fmt;
640 	vaf.va = &args;
641 	printk("%sEXT4-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
642 	va_end(args);
643 }
644 
645 #define ext4_warning_ratelimit(sb)					\
646 		___ratelimit(&(EXT4_SB(sb)->s_warning_ratelimit_state),	\
647 			     "EXT4-fs warning")
648 
649 void __ext4_warning(struct super_block *sb, const char *function,
650 		    unsigned int line, const char *fmt, ...)
651 {
652 	struct va_format vaf;
653 	va_list args;
654 
655 	if (!ext4_warning_ratelimit(sb))
656 		return;
657 
658 	va_start(args, fmt);
659 	vaf.fmt = fmt;
660 	vaf.va = &args;
661 	printk(KERN_WARNING "EXT4-fs warning (device %s): %s:%d: %pV\n",
662 	       sb->s_id, function, line, &vaf);
663 	va_end(args);
664 }
665 
666 void __ext4_warning_inode(const struct inode *inode, const char *function,
667 			  unsigned int line, const char *fmt, ...)
668 {
669 	struct va_format vaf;
670 	va_list args;
671 
672 	if (!ext4_warning_ratelimit(inode->i_sb))
673 		return;
674 
675 	va_start(args, fmt);
676 	vaf.fmt = fmt;
677 	vaf.va = &args;
678 	printk(KERN_WARNING "EXT4-fs warning (device %s): %s:%d: "
679 	       "inode #%lu: comm %s: %pV\n", inode->i_sb->s_id,
680 	       function, line, inode->i_ino, current->comm, &vaf);
681 	va_end(args);
682 }
683 
684 void __ext4_grp_locked_error(const char *function, unsigned int line,
685 			     struct super_block *sb, ext4_group_t grp,
686 			     unsigned long ino, ext4_fsblk_t block,
687 			     const char *fmt, ...)
688 __releases(bitlock)
689 __acquires(bitlock)
690 {
691 	struct va_format vaf;
692 	va_list args;
693 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
694 
695 	es->s_last_error_ino = cpu_to_le32(ino);
696 	es->s_last_error_block = cpu_to_le64(block);
697 	__save_error_info(sb, function, line);
698 
699 	if (ext4_error_ratelimit(sb)) {
700 		va_start(args, fmt);
701 		vaf.fmt = fmt;
702 		vaf.va = &args;
703 		printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: group %u, ",
704 		       sb->s_id, function, line, grp);
705 		if (ino)
706 			printk(KERN_CONT "inode %lu: ", ino);
707 		if (block)
708 			printk(KERN_CONT "block %llu:",
709 			       (unsigned long long) block);
710 		printk(KERN_CONT "%pV\n", &vaf);
711 		va_end(args);
712 	}
713 
714 	if (test_opt(sb, ERRORS_CONT)) {
715 		ext4_commit_super(sb, 0);
716 		return;
717 	}
718 
719 	ext4_unlock_group(sb, grp);
720 	ext4_handle_error(sb);
721 	/*
722 	 * We only get here in the ERRORS_RO case; relocking the group
723 	 * may be dangerous, but nothing bad will happen since the
724 	 * filesystem will have already been marked read/only and the
725 	 * journal has been aborted.  We return 1 as a hint to callers
726 	 * who might what to use the return value from
727 	 * ext4_grp_locked_error() to distinguish between the
728 	 * ERRORS_CONT and ERRORS_RO case, and perhaps return more
729 	 * aggressively from the ext4 function in question, with a
730 	 * more appropriate error code.
731 	 */
732 	ext4_lock_group(sb, grp);
733 	return;
734 }
735 
736 void ext4_update_dynamic_rev(struct super_block *sb)
737 {
738 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
739 
740 	if (le32_to_cpu(es->s_rev_level) > EXT4_GOOD_OLD_REV)
741 		return;
742 
743 	ext4_warning(sb,
744 		     "updating to rev %d because of new feature flag, "
745 		     "running e2fsck is recommended",
746 		     EXT4_DYNAMIC_REV);
747 
748 	es->s_first_ino = cpu_to_le32(EXT4_GOOD_OLD_FIRST_INO);
749 	es->s_inode_size = cpu_to_le16(EXT4_GOOD_OLD_INODE_SIZE);
750 	es->s_rev_level = cpu_to_le32(EXT4_DYNAMIC_REV);
751 	/* leave es->s_feature_*compat flags alone */
752 	/* es->s_uuid will be set by e2fsck if empty */
753 
754 	/*
755 	 * The rest of the superblock fields should be zero, and if not it
756 	 * means they are likely already in use, so leave them alone.  We
757 	 * can leave it up to e2fsck to clean up any inconsistencies there.
758 	 */
759 }
760 
761 /*
762  * Open the external journal device
763  */
764 static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb)
765 {
766 	struct block_device *bdev;
767 	char b[BDEVNAME_SIZE];
768 
769 	bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb);
770 	if (IS_ERR(bdev))
771 		goto fail;
772 	return bdev;
773 
774 fail:
775 	ext4_msg(sb, KERN_ERR, "failed to open journal device %s: %ld",
776 			__bdevname(dev, b), PTR_ERR(bdev));
777 	return NULL;
778 }
779 
780 /*
781  * Release the journal device
782  */
783 static void ext4_blkdev_put(struct block_device *bdev)
784 {
785 	blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
786 }
787 
788 static void ext4_blkdev_remove(struct ext4_sb_info *sbi)
789 {
790 	struct block_device *bdev;
791 	bdev = sbi->journal_bdev;
792 	if (bdev) {
793 		ext4_blkdev_put(bdev);
794 		sbi->journal_bdev = NULL;
795 	}
796 }
797 
798 static inline struct inode *orphan_list_entry(struct list_head *l)
799 {
800 	return &list_entry(l, struct ext4_inode_info, i_orphan)->vfs_inode;
801 }
802 
803 static void dump_orphan_list(struct super_block *sb, struct ext4_sb_info *sbi)
804 {
805 	struct list_head *l;
806 
807 	ext4_msg(sb, KERN_ERR, "sb orphan head is %d",
808 		 le32_to_cpu(sbi->s_es->s_last_orphan));
809 
810 	printk(KERN_ERR "sb_info orphan list:\n");
811 	list_for_each(l, &sbi->s_orphan) {
812 		struct inode *inode = orphan_list_entry(l);
813 		printk(KERN_ERR "  "
814 		       "inode %s:%lu at %p: mode %o, nlink %d, next %d\n",
815 		       inode->i_sb->s_id, inode->i_ino, inode,
816 		       inode->i_mode, inode->i_nlink,
817 		       NEXT_ORPHAN(inode));
818 	}
819 }
820 
821 static void ext4_put_super(struct super_block *sb)
822 {
823 	struct ext4_sb_info *sbi = EXT4_SB(sb);
824 	struct ext4_super_block *es = sbi->s_es;
825 	int i, err;
826 
827 	ext4_unregister_li_request(sb);
828 	dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
829 
830 	flush_workqueue(sbi->rsv_conversion_wq);
831 	destroy_workqueue(sbi->rsv_conversion_wq);
832 
833 	if (sbi->s_journal) {
834 		err = jbd2_journal_destroy(sbi->s_journal);
835 		sbi->s_journal = NULL;
836 		if (err < 0)
837 			ext4_abort(sb, "Couldn't clean up the journal");
838 	}
839 
840 	ext4_unregister_sysfs(sb);
841 	ext4_es_unregister_shrinker(sbi);
842 	del_timer_sync(&sbi->s_err_report);
843 	ext4_release_system_zone(sb);
844 	ext4_mb_release(sb);
845 	ext4_ext_release(sb);
846 
847 	if (!(sb->s_flags & MS_RDONLY)) {
848 		ext4_clear_feature_journal_needs_recovery(sb);
849 		es->s_state = cpu_to_le16(sbi->s_mount_state);
850 	}
851 	if (!(sb->s_flags & MS_RDONLY))
852 		ext4_commit_super(sb, 1);
853 
854 	for (i = 0; i < sbi->s_gdb_count; i++)
855 		brelse(sbi->s_group_desc[i]);
856 	kvfree(sbi->s_group_desc);
857 	kvfree(sbi->s_flex_groups);
858 	percpu_counter_destroy(&sbi->s_freeclusters_counter);
859 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
860 	percpu_counter_destroy(&sbi->s_dirs_counter);
861 	percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
862 	percpu_free_rwsem(&sbi->s_journal_flag_rwsem);
863 	brelse(sbi->s_sbh);
864 #ifdef CONFIG_QUOTA
865 	for (i = 0; i < EXT4_MAXQUOTAS; i++)
866 		kfree(sbi->s_qf_names[i]);
867 #endif
868 
869 	/* Debugging code just in case the in-memory inode orphan list
870 	 * isn't empty.  The on-disk one can be non-empty if we've
871 	 * detected an error and taken the fs readonly, but the
872 	 * in-memory list had better be clean by this point. */
873 	if (!list_empty(&sbi->s_orphan))
874 		dump_orphan_list(sb, sbi);
875 	J_ASSERT(list_empty(&sbi->s_orphan));
876 
877 	sync_blockdev(sb->s_bdev);
878 	invalidate_bdev(sb->s_bdev);
879 	if (sbi->journal_bdev && sbi->journal_bdev != sb->s_bdev) {
880 		/*
881 		 * Invalidate the journal device's buffers.  We don't want them
882 		 * floating about in memory - the physical journal device may
883 		 * hotswapped, and it breaks the `ro-after' testing code.
884 		 */
885 		sync_blockdev(sbi->journal_bdev);
886 		invalidate_bdev(sbi->journal_bdev);
887 		ext4_blkdev_remove(sbi);
888 	}
889 	if (sbi->s_mb_cache) {
890 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
891 		sbi->s_mb_cache = NULL;
892 	}
893 	if (sbi->s_mmp_tsk)
894 		kthread_stop(sbi->s_mmp_tsk);
895 	sb->s_fs_info = NULL;
896 	/*
897 	 * Now that we are completely done shutting down the
898 	 * superblock, we need to actually destroy the kobject.
899 	 */
900 	kobject_put(&sbi->s_kobj);
901 	wait_for_completion(&sbi->s_kobj_unregister);
902 	if (sbi->s_chksum_driver)
903 		crypto_free_shash(sbi->s_chksum_driver);
904 	kfree(sbi->s_blockgroup_lock);
905 	kfree(sbi);
906 }
907 
908 static struct kmem_cache *ext4_inode_cachep;
909 
910 /*
911  * Called inside transaction, so use GFP_NOFS
912  */
913 static struct inode *ext4_alloc_inode(struct super_block *sb)
914 {
915 	struct ext4_inode_info *ei;
916 
917 	ei = kmem_cache_alloc(ext4_inode_cachep, GFP_NOFS);
918 	if (!ei)
919 		return NULL;
920 
921 	ei->vfs_inode.i_version = 1;
922 	spin_lock_init(&ei->i_raw_lock);
923 	INIT_LIST_HEAD(&ei->i_prealloc_list);
924 	spin_lock_init(&ei->i_prealloc_lock);
925 	ext4_es_init_tree(&ei->i_es_tree);
926 	rwlock_init(&ei->i_es_lock);
927 	INIT_LIST_HEAD(&ei->i_es_list);
928 	ei->i_es_all_nr = 0;
929 	ei->i_es_shk_nr = 0;
930 	ei->i_es_shrink_lblk = 0;
931 	ei->i_reserved_data_blocks = 0;
932 	ei->i_reserved_meta_blocks = 0;
933 	ei->i_allocated_meta_blocks = 0;
934 	ei->i_da_metadata_calc_len = 0;
935 	ei->i_da_metadata_calc_last_lblock = 0;
936 	spin_lock_init(&(ei->i_block_reservation_lock));
937 #ifdef CONFIG_QUOTA
938 	ei->i_reserved_quota = 0;
939 	memset(&ei->i_dquot, 0, sizeof(ei->i_dquot));
940 #endif
941 	ei->jinode = NULL;
942 	INIT_LIST_HEAD(&ei->i_rsv_conversion_list);
943 	spin_lock_init(&ei->i_completed_io_lock);
944 	ei->i_sync_tid = 0;
945 	ei->i_datasync_tid = 0;
946 	atomic_set(&ei->i_unwritten, 0);
947 	INIT_WORK(&ei->i_rsv_conversion_work, ext4_end_io_rsv_work);
948 	return &ei->vfs_inode;
949 }
950 
951 static int ext4_drop_inode(struct inode *inode)
952 {
953 	int drop = generic_drop_inode(inode);
954 
955 	trace_ext4_drop_inode(inode, drop);
956 	return drop;
957 }
958 
959 static void ext4_i_callback(struct rcu_head *head)
960 {
961 	struct inode *inode = container_of(head, struct inode, i_rcu);
962 	kmem_cache_free(ext4_inode_cachep, EXT4_I(inode));
963 }
964 
965 static void ext4_destroy_inode(struct inode *inode)
966 {
967 	if (!list_empty(&(EXT4_I(inode)->i_orphan))) {
968 		ext4_msg(inode->i_sb, KERN_ERR,
969 			 "Inode %lu (%p): orphan list check failed!",
970 			 inode->i_ino, EXT4_I(inode));
971 		print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 16, 4,
972 				EXT4_I(inode), sizeof(struct ext4_inode_info),
973 				true);
974 		dump_stack();
975 	}
976 	call_rcu(&inode->i_rcu, ext4_i_callback);
977 }
978 
979 static void init_once(void *foo)
980 {
981 	struct ext4_inode_info *ei = (struct ext4_inode_info *) foo;
982 
983 	INIT_LIST_HEAD(&ei->i_orphan);
984 	init_rwsem(&ei->xattr_sem);
985 	init_rwsem(&ei->i_data_sem);
986 	init_rwsem(&ei->i_mmap_sem);
987 	inode_init_once(&ei->vfs_inode);
988 }
989 
990 static int __init init_inodecache(void)
991 {
992 	ext4_inode_cachep = kmem_cache_create("ext4_inode_cache",
993 					     sizeof(struct ext4_inode_info),
994 					     0, (SLAB_RECLAIM_ACCOUNT|
995 						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
996 					     init_once);
997 	if (ext4_inode_cachep == NULL)
998 		return -ENOMEM;
999 	return 0;
1000 }
1001 
1002 static void destroy_inodecache(void)
1003 {
1004 	/*
1005 	 * Make sure all delayed rcu free inodes are flushed before we
1006 	 * destroy cache.
1007 	 */
1008 	rcu_barrier();
1009 	kmem_cache_destroy(ext4_inode_cachep);
1010 }
1011 
1012 void ext4_clear_inode(struct inode *inode)
1013 {
1014 	invalidate_inode_buffers(inode);
1015 	clear_inode(inode);
1016 	dquot_drop(inode);
1017 	ext4_discard_preallocations(inode);
1018 	ext4_es_remove_extent(inode, 0, EXT_MAX_BLOCKS);
1019 	if (EXT4_I(inode)->jinode) {
1020 		jbd2_journal_release_jbd_inode(EXT4_JOURNAL(inode),
1021 					       EXT4_I(inode)->jinode);
1022 		jbd2_free_inode(EXT4_I(inode)->jinode);
1023 		EXT4_I(inode)->jinode = NULL;
1024 	}
1025 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1026 	fscrypt_put_encryption_info(inode, NULL);
1027 #endif
1028 }
1029 
1030 static struct inode *ext4_nfs_get_inode(struct super_block *sb,
1031 					u64 ino, u32 generation)
1032 {
1033 	struct inode *inode;
1034 
1035 	if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
1036 		return ERR_PTR(-ESTALE);
1037 	if (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
1038 		return ERR_PTR(-ESTALE);
1039 
1040 	/* iget isn't really right if the inode is currently unallocated!!
1041 	 *
1042 	 * ext4_read_inode will return a bad_inode if the inode had been
1043 	 * deleted, so we should be safe.
1044 	 *
1045 	 * Currently we don't know the generation for parent directory, so
1046 	 * a generation of 0 means "accept any"
1047 	 */
1048 	inode = ext4_iget_normal(sb, ino);
1049 	if (IS_ERR(inode))
1050 		return ERR_CAST(inode);
1051 	if (generation && inode->i_generation != generation) {
1052 		iput(inode);
1053 		return ERR_PTR(-ESTALE);
1054 	}
1055 
1056 	return inode;
1057 }
1058 
1059 static struct dentry *ext4_fh_to_dentry(struct super_block *sb, struct fid *fid,
1060 					int fh_len, int fh_type)
1061 {
1062 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
1063 				    ext4_nfs_get_inode);
1064 }
1065 
1066 static struct dentry *ext4_fh_to_parent(struct super_block *sb, struct fid *fid,
1067 					int fh_len, int fh_type)
1068 {
1069 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
1070 				    ext4_nfs_get_inode);
1071 }
1072 
1073 /*
1074  * Try to release metadata pages (indirect blocks, directories) which are
1075  * mapped via the block device.  Since these pages could have journal heads
1076  * which would prevent try_to_free_buffers() from freeing them, we must use
1077  * jbd2 layer's try_to_free_buffers() function to release them.
1078  */
1079 static int bdev_try_to_free_page(struct super_block *sb, struct page *page,
1080 				 gfp_t wait)
1081 {
1082 	journal_t *journal = EXT4_SB(sb)->s_journal;
1083 
1084 	WARN_ON(PageChecked(page));
1085 	if (!page_has_buffers(page))
1086 		return 0;
1087 	if (journal)
1088 		return jbd2_journal_try_to_free_buffers(journal, page,
1089 						wait & ~__GFP_DIRECT_RECLAIM);
1090 	return try_to_free_buffers(page);
1091 }
1092 
1093 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1094 static int ext4_get_context(struct inode *inode, void *ctx, size_t len)
1095 {
1096 	return ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION,
1097 				 EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, ctx, len);
1098 }
1099 
1100 static int ext4_key_prefix(struct inode *inode, u8 **key)
1101 {
1102 	*key = EXT4_SB(inode->i_sb)->key_prefix;
1103 	return EXT4_SB(inode->i_sb)->key_prefix_size;
1104 }
1105 
1106 static int ext4_prepare_context(struct inode *inode)
1107 {
1108 	return ext4_convert_inline_data(inode);
1109 }
1110 
1111 static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
1112 							void *fs_data)
1113 {
1114 	handle_t *handle;
1115 	int res, res2;
1116 
1117 	/* fs_data is null when internally used. */
1118 	if (fs_data) {
1119 		res  = ext4_xattr_set(inode, EXT4_XATTR_INDEX_ENCRYPTION,
1120 				EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, ctx,
1121 				len, 0);
1122 		if (!res) {
1123 			ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
1124 			ext4_clear_inode_state(inode,
1125 					EXT4_STATE_MAY_INLINE_DATA);
1126 		}
1127 		return res;
1128 	}
1129 
1130 	handle = ext4_journal_start(inode, EXT4_HT_MISC,
1131 			ext4_jbd2_credits_xattr(inode));
1132 	if (IS_ERR(handle))
1133 		return PTR_ERR(handle);
1134 
1135 	res = ext4_xattr_set(inode, EXT4_XATTR_INDEX_ENCRYPTION,
1136 			EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, ctx,
1137 			len, 0);
1138 	if (!res) {
1139 		ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
1140 		res = ext4_mark_inode_dirty(handle, inode);
1141 		if (res)
1142 			EXT4_ERROR_INODE(inode, "Failed to mark inode dirty");
1143 	}
1144 	res2 = ext4_journal_stop(handle);
1145 	if (!res)
1146 		res = res2;
1147 	return res;
1148 }
1149 
1150 static int ext4_dummy_context(struct inode *inode)
1151 {
1152 	return DUMMY_ENCRYPTION_ENABLED(EXT4_SB(inode->i_sb));
1153 }
1154 
1155 static unsigned ext4_max_namelen(struct inode *inode)
1156 {
1157 	return S_ISLNK(inode->i_mode) ? inode->i_sb->s_blocksize :
1158 		EXT4_NAME_LEN;
1159 }
1160 
1161 static struct fscrypt_operations ext4_cryptops = {
1162 	.get_context		= ext4_get_context,
1163 	.key_prefix		= ext4_key_prefix,
1164 	.prepare_context	= ext4_prepare_context,
1165 	.set_context		= ext4_set_context,
1166 	.dummy_context		= ext4_dummy_context,
1167 	.is_encrypted		= ext4_encrypted_inode,
1168 	.empty_dir		= ext4_empty_dir,
1169 	.max_namelen		= ext4_max_namelen,
1170 };
1171 #else
1172 static struct fscrypt_operations ext4_cryptops = {
1173 	.is_encrypted		= ext4_encrypted_inode,
1174 };
1175 #endif
1176 
1177 #ifdef CONFIG_QUOTA
1178 static char *quotatypes[] = INITQFNAMES;
1179 #define QTYPE2NAME(t) (quotatypes[t])
1180 
1181 static int ext4_write_dquot(struct dquot *dquot);
1182 static int ext4_acquire_dquot(struct dquot *dquot);
1183 static int ext4_release_dquot(struct dquot *dquot);
1184 static int ext4_mark_dquot_dirty(struct dquot *dquot);
1185 static int ext4_write_info(struct super_block *sb, int type);
1186 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
1187 			 struct path *path);
1188 static int ext4_quota_off(struct super_block *sb, int type);
1189 static int ext4_quota_on_mount(struct super_block *sb, int type);
1190 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
1191 			       size_t len, loff_t off);
1192 static ssize_t ext4_quota_write(struct super_block *sb, int type,
1193 				const char *data, size_t len, loff_t off);
1194 static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
1195 			     unsigned int flags);
1196 static int ext4_enable_quotas(struct super_block *sb);
1197 static int ext4_get_next_id(struct super_block *sb, struct kqid *qid);
1198 
1199 static struct dquot **ext4_get_dquots(struct inode *inode)
1200 {
1201 	return EXT4_I(inode)->i_dquot;
1202 }
1203 
1204 static const struct dquot_operations ext4_quota_operations = {
1205 	.get_reserved_space = ext4_get_reserved_space,
1206 	.write_dquot	= ext4_write_dquot,
1207 	.acquire_dquot	= ext4_acquire_dquot,
1208 	.release_dquot	= ext4_release_dquot,
1209 	.mark_dirty	= ext4_mark_dquot_dirty,
1210 	.write_info	= ext4_write_info,
1211 	.alloc_dquot	= dquot_alloc,
1212 	.destroy_dquot	= dquot_destroy,
1213 	.get_projid	= ext4_get_projid,
1214 	.get_next_id	= ext4_get_next_id,
1215 };
1216 
1217 static const struct quotactl_ops ext4_qctl_operations = {
1218 	.quota_on	= ext4_quota_on,
1219 	.quota_off	= ext4_quota_off,
1220 	.quota_sync	= dquot_quota_sync,
1221 	.get_state	= dquot_get_state,
1222 	.set_info	= dquot_set_dqinfo,
1223 	.get_dqblk	= dquot_get_dqblk,
1224 	.set_dqblk	= dquot_set_dqblk,
1225 	.get_nextdqblk	= dquot_get_next_dqblk,
1226 };
1227 #endif
1228 
1229 static const struct super_operations ext4_sops = {
1230 	.alloc_inode	= ext4_alloc_inode,
1231 	.destroy_inode	= ext4_destroy_inode,
1232 	.write_inode	= ext4_write_inode,
1233 	.dirty_inode	= ext4_dirty_inode,
1234 	.drop_inode	= ext4_drop_inode,
1235 	.evict_inode	= ext4_evict_inode,
1236 	.put_super	= ext4_put_super,
1237 	.sync_fs	= ext4_sync_fs,
1238 	.freeze_fs	= ext4_freeze,
1239 	.unfreeze_fs	= ext4_unfreeze,
1240 	.statfs		= ext4_statfs,
1241 	.remount_fs	= ext4_remount,
1242 	.show_options	= ext4_show_options,
1243 #ifdef CONFIG_QUOTA
1244 	.quota_read	= ext4_quota_read,
1245 	.quota_write	= ext4_quota_write,
1246 	.get_dquots	= ext4_get_dquots,
1247 #endif
1248 	.bdev_try_to_free_page = bdev_try_to_free_page,
1249 };
1250 
1251 static const struct export_operations ext4_export_ops = {
1252 	.fh_to_dentry = ext4_fh_to_dentry,
1253 	.fh_to_parent = ext4_fh_to_parent,
1254 	.get_parent = ext4_get_parent,
1255 };
1256 
1257 enum {
1258 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
1259 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
1260 	Opt_nouid32, Opt_debug, Opt_removed,
1261 	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
1262 	Opt_auto_da_alloc, Opt_noauto_da_alloc, Opt_noload,
1263 	Opt_commit, Opt_min_batch_time, Opt_max_batch_time, Opt_journal_dev,
1264 	Opt_journal_path, Opt_journal_checksum, Opt_journal_async_commit,
1265 	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
1266 	Opt_data_err_abort, Opt_data_err_ignore, Opt_test_dummy_encryption,
1267 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
1268 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
1269 	Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err,
1270 	Opt_usrquota, Opt_grpquota, Opt_i_version, Opt_dax,
1271 	Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_mblk_io_submit,
1272 	Opt_lazytime, Opt_nolazytime,
1273 	Opt_nomblk_io_submit, Opt_block_validity, Opt_noblock_validity,
1274 	Opt_inode_readahead_blks, Opt_journal_ioprio,
1275 	Opt_dioread_nolock, Opt_dioread_lock,
1276 	Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
1277 	Opt_max_dir_size_kb, Opt_nojournal_checksum,
1278 };
1279 
1280 static const match_table_t tokens = {
1281 	{Opt_bsd_df, "bsddf"},
1282 	{Opt_minix_df, "minixdf"},
1283 	{Opt_grpid, "grpid"},
1284 	{Opt_grpid, "bsdgroups"},
1285 	{Opt_nogrpid, "nogrpid"},
1286 	{Opt_nogrpid, "sysvgroups"},
1287 	{Opt_resgid, "resgid=%u"},
1288 	{Opt_resuid, "resuid=%u"},
1289 	{Opt_sb, "sb=%u"},
1290 	{Opt_err_cont, "errors=continue"},
1291 	{Opt_err_panic, "errors=panic"},
1292 	{Opt_err_ro, "errors=remount-ro"},
1293 	{Opt_nouid32, "nouid32"},
1294 	{Opt_debug, "debug"},
1295 	{Opt_removed, "oldalloc"},
1296 	{Opt_removed, "orlov"},
1297 	{Opt_user_xattr, "user_xattr"},
1298 	{Opt_nouser_xattr, "nouser_xattr"},
1299 	{Opt_acl, "acl"},
1300 	{Opt_noacl, "noacl"},
1301 	{Opt_noload, "norecovery"},
1302 	{Opt_noload, "noload"},
1303 	{Opt_removed, "nobh"},
1304 	{Opt_removed, "bh"},
1305 	{Opt_commit, "commit=%u"},
1306 	{Opt_min_batch_time, "min_batch_time=%u"},
1307 	{Opt_max_batch_time, "max_batch_time=%u"},
1308 	{Opt_journal_dev, "journal_dev=%u"},
1309 	{Opt_journal_path, "journal_path=%s"},
1310 	{Opt_journal_checksum, "journal_checksum"},
1311 	{Opt_nojournal_checksum, "nojournal_checksum"},
1312 	{Opt_journal_async_commit, "journal_async_commit"},
1313 	{Opt_abort, "abort"},
1314 	{Opt_data_journal, "data=journal"},
1315 	{Opt_data_ordered, "data=ordered"},
1316 	{Opt_data_writeback, "data=writeback"},
1317 	{Opt_data_err_abort, "data_err=abort"},
1318 	{Opt_data_err_ignore, "data_err=ignore"},
1319 	{Opt_offusrjquota, "usrjquota="},
1320 	{Opt_usrjquota, "usrjquota=%s"},
1321 	{Opt_offgrpjquota, "grpjquota="},
1322 	{Opt_grpjquota, "grpjquota=%s"},
1323 	{Opt_jqfmt_vfsold, "jqfmt=vfsold"},
1324 	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
1325 	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
1326 	{Opt_grpquota, "grpquota"},
1327 	{Opt_noquota, "noquota"},
1328 	{Opt_quota, "quota"},
1329 	{Opt_usrquota, "usrquota"},
1330 	{Opt_barrier, "barrier=%u"},
1331 	{Opt_barrier, "barrier"},
1332 	{Opt_nobarrier, "nobarrier"},
1333 	{Opt_i_version, "i_version"},
1334 	{Opt_dax, "dax"},
1335 	{Opt_stripe, "stripe=%u"},
1336 	{Opt_delalloc, "delalloc"},
1337 	{Opt_lazytime, "lazytime"},
1338 	{Opt_nolazytime, "nolazytime"},
1339 	{Opt_nodelalloc, "nodelalloc"},
1340 	{Opt_removed, "mblk_io_submit"},
1341 	{Opt_removed, "nomblk_io_submit"},
1342 	{Opt_block_validity, "block_validity"},
1343 	{Opt_noblock_validity, "noblock_validity"},
1344 	{Opt_inode_readahead_blks, "inode_readahead_blks=%u"},
1345 	{Opt_journal_ioprio, "journal_ioprio=%u"},
1346 	{Opt_auto_da_alloc, "auto_da_alloc=%u"},
1347 	{Opt_auto_da_alloc, "auto_da_alloc"},
1348 	{Opt_noauto_da_alloc, "noauto_da_alloc"},
1349 	{Opt_dioread_nolock, "dioread_nolock"},
1350 	{Opt_dioread_lock, "dioread_lock"},
1351 	{Opt_discard, "discard"},
1352 	{Opt_nodiscard, "nodiscard"},
1353 	{Opt_init_itable, "init_itable=%u"},
1354 	{Opt_init_itable, "init_itable"},
1355 	{Opt_noinit_itable, "noinit_itable"},
1356 	{Opt_max_dir_size_kb, "max_dir_size_kb=%u"},
1357 	{Opt_test_dummy_encryption, "test_dummy_encryption"},
1358 	{Opt_removed, "check=none"},	/* mount option from ext2/3 */
1359 	{Opt_removed, "nocheck"},	/* mount option from ext2/3 */
1360 	{Opt_removed, "reservation"},	/* mount option from ext2/3 */
1361 	{Opt_removed, "noreservation"}, /* mount option from ext2/3 */
1362 	{Opt_removed, "journal=%u"},	/* mount option from ext2/3 */
1363 	{Opt_err, NULL},
1364 };
1365 
1366 static ext4_fsblk_t get_sb_block(void **data)
1367 {
1368 	ext4_fsblk_t	sb_block;
1369 	char		*options = (char *) *data;
1370 
1371 	if (!options || strncmp(options, "sb=", 3) != 0)
1372 		return 1;	/* Default location */
1373 
1374 	options += 3;
1375 	/* TODO: use simple_strtoll with >32bit ext4 */
1376 	sb_block = simple_strtoul(options, &options, 0);
1377 	if (*options && *options != ',') {
1378 		printk(KERN_ERR "EXT4-fs: Invalid sb specification: %s\n",
1379 		       (char *) *data);
1380 		return 1;
1381 	}
1382 	if (*options == ',')
1383 		options++;
1384 	*data = (void *) options;
1385 
1386 	return sb_block;
1387 }
1388 
1389 #define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))
1390 static char deprecated_msg[] = "Mount option \"%s\" will be removed by %s\n"
1391 	"Contact linux-ext4@vger.kernel.org if you think we should keep it.\n";
1392 
1393 #ifdef CONFIG_QUOTA
1394 static int set_qf_name(struct super_block *sb, int qtype, substring_t *args)
1395 {
1396 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1397 	char *qname;
1398 	int ret = -1;
1399 
1400 	if (sb_any_quota_loaded(sb) &&
1401 		!sbi->s_qf_names[qtype]) {
1402 		ext4_msg(sb, KERN_ERR,
1403 			"Cannot change journaled "
1404 			"quota options when quota turned on");
1405 		return -1;
1406 	}
1407 	if (ext4_has_feature_quota(sb)) {
1408 		ext4_msg(sb, KERN_INFO, "Journaled quota options "
1409 			 "ignored when QUOTA feature is enabled");
1410 		return 1;
1411 	}
1412 	qname = match_strdup(args);
1413 	if (!qname) {
1414 		ext4_msg(sb, KERN_ERR,
1415 			"Not enough memory for storing quotafile name");
1416 		return -1;
1417 	}
1418 	if (sbi->s_qf_names[qtype]) {
1419 		if (strcmp(sbi->s_qf_names[qtype], qname) == 0)
1420 			ret = 1;
1421 		else
1422 			ext4_msg(sb, KERN_ERR,
1423 				 "%s quota file already specified",
1424 				 QTYPE2NAME(qtype));
1425 		goto errout;
1426 	}
1427 	if (strchr(qname, '/')) {
1428 		ext4_msg(sb, KERN_ERR,
1429 			"quotafile must be on filesystem root");
1430 		goto errout;
1431 	}
1432 	sbi->s_qf_names[qtype] = qname;
1433 	set_opt(sb, QUOTA);
1434 	return 1;
1435 errout:
1436 	kfree(qname);
1437 	return ret;
1438 }
1439 
1440 static int clear_qf_name(struct super_block *sb, int qtype)
1441 {
1442 
1443 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1444 
1445 	if (sb_any_quota_loaded(sb) &&
1446 		sbi->s_qf_names[qtype]) {
1447 		ext4_msg(sb, KERN_ERR, "Cannot change journaled quota options"
1448 			" when quota turned on");
1449 		return -1;
1450 	}
1451 	kfree(sbi->s_qf_names[qtype]);
1452 	sbi->s_qf_names[qtype] = NULL;
1453 	return 1;
1454 }
1455 #endif
1456 
1457 #define MOPT_SET	0x0001
1458 #define MOPT_CLEAR	0x0002
1459 #define MOPT_NOSUPPORT	0x0004
1460 #define MOPT_EXPLICIT	0x0008
1461 #define MOPT_CLEAR_ERR	0x0010
1462 #define MOPT_GTE0	0x0020
1463 #ifdef CONFIG_QUOTA
1464 #define MOPT_Q		0
1465 #define MOPT_QFMT	0x0040
1466 #else
1467 #define MOPT_Q		MOPT_NOSUPPORT
1468 #define MOPT_QFMT	MOPT_NOSUPPORT
1469 #endif
1470 #define MOPT_DATAJ	0x0080
1471 #define MOPT_NO_EXT2	0x0100
1472 #define MOPT_NO_EXT3	0x0200
1473 #define MOPT_EXT4_ONLY	(MOPT_NO_EXT2 | MOPT_NO_EXT3)
1474 #define MOPT_STRING	0x0400
1475 
1476 static const struct mount_opts {
1477 	int	token;
1478 	int	mount_opt;
1479 	int	flags;
1480 } ext4_mount_opts[] = {
1481 	{Opt_minix_df, EXT4_MOUNT_MINIX_DF, MOPT_SET},
1482 	{Opt_bsd_df, EXT4_MOUNT_MINIX_DF, MOPT_CLEAR},
1483 	{Opt_grpid, EXT4_MOUNT_GRPID, MOPT_SET},
1484 	{Opt_nogrpid, EXT4_MOUNT_GRPID, MOPT_CLEAR},
1485 	{Opt_block_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_SET},
1486 	{Opt_noblock_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_CLEAR},
1487 	{Opt_dioread_nolock, EXT4_MOUNT_DIOREAD_NOLOCK,
1488 	 MOPT_EXT4_ONLY | MOPT_SET},
1489 	{Opt_dioread_lock, EXT4_MOUNT_DIOREAD_NOLOCK,
1490 	 MOPT_EXT4_ONLY | MOPT_CLEAR},
1491 	{Opt_discard, EXT4_MOUNT_DISCARD, MOPT_SET},
1492 	{Opt_nodiscard, EXT4_MOUNT_DISCARD, MOPT_CLEAR},
1493 	{Opt_delalloc, EXT4_MOUNT_DELALLOC,
1494 	 MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
1495 	{Opt_nodelalloc, EXT4_MOUNT_DELALLOC,
1496 	 MOPT_EXT4_ONLY | MOPT_CLEAR},
1497 	{Opt_nojournal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,
1498 	 MOPT_EXT4_ONLY | MOPT_CLEAR},
1499 	{Opt_journal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,
1500 	 MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
1501 	{Opt_journal_async_commit, (EXT4_MOUNT_JOURNAL_ASYNC_COMMIT |
1502 				    EXT4_MOUNT_JOURNAL_CHECKSUM),
1503 	 MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
1504 	{Opt_noload, EXT4_MOUNT_NOLOAD, MOPT_NO_EXT2 | MOPT_SET},
1505 	{Opt_err_panic, EXT4_MOUNT_ERRORS_PANIC, MOPT_SET | MOPT_CLEAR_ERR},
1506 	{Opt_err_ro, EXT4_MOUNT_ERRORS_RO, MOPT_SET | MOPT_CLEAR_ERR},
1507 	{Opt_err_cont, EXT4_MOUNT_ERRORS_CONT, MOPT_SET | MOPT_CLEAR_ERR},
1508 	{Opt_data_err_abort, EXT4_MOUNT_DATA_ERR_ABORT,
1509 	 MOPT_NO_EXT2},
1510 	{Opt_data_err_ignore, EXT4_MOUNT_DATA_ERR_ABORT,
1511 	 MOPT_NO_EXT2},
1512 	{Opt_barrier, EXT4_MOUNT_BARRIER, MOPT_SET},
1513 	{Opt_nobarrier, EXT4_MOUNT_BARRIER, MOPT_CLEAR},
1514 	{Opt_noauto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_SET},
1515 	{Opt_auto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_CLEAR},
1516 	{Opt_noinit_itable, EXT4_MOUNT_INIT_INODE_TABLE, MOPT_CLEAR},
1517 	{Opt_commit, 0, MOPT_GTE0},
1518 	{Opt_max_batch_time, 0, MOPT_GTE0},
1519 	{Opt_min_batch_time, 0, MOPT_GTE0},
1520 	{Opt_inode_readahead_blks, 0, MOPT_GTE0},
1521 	{Opt_init_itable, 0, MOPT_GTE0},
1522 	{Opt_dax, EXT4_MOUNT_DAX, MOPT_SET},
1523 	{Opt_stripe, 0, MOPT_GTE0},
1524 	{Opt_resuid, 0, MOPT_GTE0},
1525 	{Opt_resgid, 0, MOPT_GTE0},
1526 	{Opt_journal_dev, 0, MOPT_NO_EXT2 | MOPT_GTE0},
1527 	{Opt_journal_path, 0, MOPT_NO_EXT2 | MOPT_STRING},
1528 	{Opt_journal_ioprio, 0, MOPT_NO_EXT2 | MOPT_GTE0},
1529 	{Opt_data_journal, EXT4_MOUNT_JOURNAL_DATA, MOPT_NO_EXT2 | MOPT_DATAJ},
1530 	{Opt_data_ordered, EXT4_MOUNT_ORDERED_DATA, MOPT_NO_EXT2 | MOPT_DATAJ},
1531 	{Opt_data_writeback, EXT4_MOUNT_WRITEBACK_DATA,
1532 	 MOPT_NO_EXT2 | MOPT_DATAJ},
1533 	{Opt_user_xattr, EXT4_MOUNT_XATTR_USER, MOPT_SET},
1534 	{Opt_nouser_xattr, EXT4_MOUNT_XATTR_USER, MOPT_CLEAR},
1535 #ifdef CONFIG_EXT4_FS_POSIX_ACL
1536 	{Opt_acl, EXT4_MOUNT_POSIX_ACL, MOPT_SET},
1537 	{Opt_noacl, EXT4_MOUNT_POSIX_ACL, MOPT_CLEAR},
1538 #else
1539 	{Opt_acl, 0, MOPT_NOSUPPORT},
1540 	{Opt_noacl, 0, MOPT_NOSUPPORT},
1541 #endif
1542 	{Opt_nouid32, EXT4_MOUNT_NO_UID32, MOPT_SET},
1543 	{Opt_debug, EXT4_MOUNT_DEBUG, MOPT_SET},
1544 	{Opt_quota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA, MOPT_SET | MOPT_Q},
1545 	{Opt_usrquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA,
1546 							MOPT_SET | MOPT_Q},
1547 	{Opt_grpquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_GRPQUOTA,
1548 							MOPT_SET | MOPT_Q},
1549 	{Opt_noquota, (EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA |
1550 		       EXT4_MOUNT_GRPQUOTA), MOPT_CLEAR | MOPT_Q},
1551 	{Opt_usrjquota, 0, MOPT_Q},
1552 	{Opt_grpjquota, 0, MOPT_Q},
1553 	{Opt_offusrjquota, 0, MOPT_Q},
1554 	{Opt_offgrpjquota, 0, MOPT_Q},
1555 	{Opt_jqfmt_vfsold, QFMT_VFS_OLD, MOPT_QFMT},
1556 	{Opt_jqfmt_vfsv0, QFMT_VFS_V0, MOPT_QFMT},
1557 	{Opt_jqfmt_vfsv1, QFMT_VFS_V1, MOPT_QFMT},
1558 	{Opt_max_dir_size_kb, 0, MOPT_GTE0},
1559 	{Opt_test_dummy_encryption, 0, MOPT_GTE0},
1560 	{Opt_err, 0, 0}
1561 };
1562 
1563 static int handle_mount_opt(struct super_block *sb, char *opt, int token,
1564 			    substring_t *args, unsigned long *journal_devnum,
1565 			    unsigned int *journal_ioprio, int is_remount)
1566 {
1567 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1568 	const struct mount_opts *m;
1569 	kuid_t uid;
1570 	kgid_t gid;
1571 	int arg = 0;
1572 
1573 #ifdef CONFIG_QUOTA
1574 	if (token == Opt_usrjquota)
1575 		return set_qf_name(sb, USRQUOTA, &args[0]);
1576 	else if (token == Opt_grpjquota)
1577 		return set_qf_name(sb, GRPQUOTA, &args[0]);
1578 	else if (token == Opt_offusrjquota)
1579 		return clear_qf_name(sb, USRQUOTA);
1580 	else if (token == Opt_offgrpjquota)
1581 		return clear_qf_name(sb, GRPQUOTA);
1582 #endif
1583 	switch (token) {
1584 	case Opt_noacl:
1585 	case Opt_nouser_xattr:
1586 		ext4_msg(sb, KERN_WARNING, deprecated_msg, opt, "3.5");
1587 		break;
1588 	case Opt_sb:
1589 		return 1;	/* handled by get_sb_block() */
1590 	case Opt_removed:
1591 		ext4_msg(sb, KERN_WARNING, "Ignoring removed %s option", opt);
1592 		return 1;
1593 	case Opt_abort:
1594 		sbi->s_mount_flags |= EXT4_MF_FS_ABORTED;
1595 		return 1;
1596 	case Opt_i_version:
1597 		sb->s_flags |= MS_I_VERSION;
1598 		return 1;
1599 	case Opt_lazytime:
1600 		sb->s_flags |= MS_LAZYTIME;
1601 		return 1;
1602 	case Opt_nolazytime:
1603 		sb->s_flags &= ~MS_LAZYTIME;
1604 		return 1;
1605 	}
1606 
1607 	for (m = ext4_mount_opts; m->token != Opt_err; m++)
1608 		if (token == m->token)
1609 			break;
1610 
1611 	if (m->token == Opt_err) {
1612 		ext4_msg(sb, KERN_ERR, "Unrecognized mount option \"%s\" "
1613 			 "or missing value", opt);
1614 		return -1;
1615 	}
1616 
1617 	if ((m->flags & MOPT_NO_EXT2) && IS_EXT2_SB(sb)) {
1618 		ext4_msg(sb, KERN_ERR,
1619 			 "Mount option \"%s\" incompatible with ext2", opt);
1620 		return -1;
1621 	}
1622 	if ((m->flags & MOPT_NO_EXT3) && IS_EXT3_SB(sb)) {
1623 		ext4_msg(sb, KERN_ERR,
1624 			 "Mount option \"%s\" incompatible with ext3", opt);
1625 		return -1;
1626 	}
1627 
1628 	if (args->from && !(m->flags & MOPT_STRING) && match_int(args, &arg))
1629 		return -1;
1630 	if (args->from && (m->flags & MOPT_GTE0) && (arg < 0))
1631 		return -1;
1632 	if (m->flags & MOPT_EXPLICIT) {
1633 		if (m->mount_opt & EXT4_MOUNT_DELALLOC) {
1634 			set_opt2(sb, EXPLICIT_DELALLOC);
1635 		} else if (m->mount_opt & EXT4_MOUNT_JOURNAL_CHECKSUM) {
1636 			set_opt2(sb, EXPLICIT_JOURNAL_CHECKSUM);
1637 		} else
1638 			return -1;
1639 	}
1640 	if (m->flags & MOPT_CLEAR_ERR)
1641 		clear_opt(sb, ERRORS_MASK);
1642 	if (token == Opt_noquota && sb_any_quota_loaded(sb)) {
1643 		ext4_msg(sb, KERN_ERR, "Cannot change quota "
1644 			 "options when quota turned on");
1645 		return -1;
1646 	}
1647 
1648 	if (m->flags & MOPT_NOSUPPORT) {
1649 		ext4_msg(sb, KERN_ERR, "%s option not supported", opt);
1650 	} else if (token == Opt_commit) {
1651 		if (arg == 0)
1652 			arg = JBD2_DEFAULT_MAX_COMMIT_AGE;
1653 		sbi->s_commit_interval = HZ * arg;
1654 	} else if (token == Opt_max_batch_time) {
1655 		sbi->s_max_batch_time = arg;
1656 	} else if (token == Opt_min_batch_time) {
1657 		sbi->s_min_batch_time = arg;
1658 	} else if (token == Opt_inode_readahead_blks) {
1659 		if (arg && (arg > (1 << 30) || !is_power_of_2(arg))) {
1660 			ext4_msg(sb, KERN_ERR,
1661 				 "EXT4-fs: inode_readahead_blks must be "
1662 				 "0 or a power of 2 smaller than 2^31");
1663 			return -1;
1664 		}
1665 		sbi->s_inode_readahead_blks = arg;
1666 	} else if (token == Opt_init_itable) {
1667 		set_opt(sb, INIT_INODE_TABLE);
1668 		if (!args->from)
1669 			arg = EXT4_DEF_LI_WAIT_MULT;
1670 		sbi->s_li_wait_mult = arg;
1671 	} else if (token == Opt_max_dir_size_kb) {
1672 		sbi->s_max_dir_size_kb = arg;
1673 	} else if (token == Opt_stripe) {
1674 		sbi->s_stripe = arg;
1675 	} else if (token == Opt_resuid) {
1676 		uid = make_kuid(current_user_ns(), arg);
1677 		if (!uid_valid(uid)) {
1678 			ext4_msg(sb, KERN_ERR, "Invalid uid value %d", arg);
1679 			return -1;
1680 		}
1681 		sbi->s_resuid = uid;
1682 	} else if (token == Opt_resgid) {
1683 		gid = make_kgid(current_user_ns(), arg);
1684 		if (!gid_valid(gid)) {
1685 			ext4_msg(sb, KERN_ERR, "Invalid gid value %d", arg);
1686 			return -1;
1687 		}
1688 		sbi->s_resgid = gid;
1689 	} else if (token == Opt_journal_dev) {
1690 		if (is_remount) {
1691 			ext4_msg(sb, KERN_ERR,
1692 				 "Cannot specify journal on remount");
1693 			return -1;
1694 		}
1695 		*journal_devnum = arg;
1696 	} else if (token == Opt_journal_path) {
1697 		char *journal_path;
1698 		struct inode *journal_inode;
1699 		struct path path;
1700 		int error;
1701 
1702 		if (is_remount) {
1703 			ext4_msg(sb, KERN_ERR,
1704 				 "Cannot specify journal on remount");
1705 			return -1;
1706 		}
1707 		journal_path = match_strdup(&args[0]);
1708 		if (!journal_path) {
1709 			ext4_msg(sb, KERN_ERR, "error: could not dup "
1710 				"journal device string");
1711 			return -1;
1712 		}
1713 
1714 		error = kern_path(journal_path, LOOKUP_FOLLOW, &path);
1715 		if (error) {
1716 			ext4_msg(sb, KERN_ERR, "error: could not find "
1717 				"journal device path: error %d", error);
1718 			kfree(journal_path);
1719 			return -1;
1720 		}
1721 
1722 		journal_inode = d_inode(path.dentry);
1723 		if (!S_ISBLK(journal_inode->i_mode)) {
1724 			ext4_msg(sb, KERN_ERR, "error: journal path %s "
1725 				"is not a block device", journal_path);
1726 			path_put(&path);
1727 			kfree(journal_path);
1728 			return -1;
1729 		}
1730 
1731 		*journal_devnum = new_encode_dev(journal_inode->i_rdev);
1732 		path_put(&path);
1733 		kfree(journal_path);
1734 	} else if (token == Opt_journal_ioprio) {
1735 		if (arg > 7) {
1736 			ext4_msg(sb, KERN_ERR, "Invalid journal IO priority"
1737 				 " (must be 0-7)");
1738 			return -1;
1739 		}
1740 		*journal_ioprio =
1741 			IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, arg);
1742 	} else if (token == Opt_test_dummy_encryption) {
1743 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1744 		sbi->s_mount_flags |= EXT4_MF_TEST_DUMMY_ENCRYPTION;
1745 		ext4_msg(sb, KERN_WARNING,
1746 			 "Test dummy encryption mode enabled");
1747 #else
1748 		ext4_msg(sb, KERN_WARNING,
1749 			 "Test dummy encryption mount option ignored");
1750 #endif
1751 	} else if (m->flags & MOPT_DATAJ) {
1752 		if (is_remount) {
1753 			if (!sbi->s_journal)
1754 				ext4_msg(sb, KERN_WARNING, "Remounting file system with no journal so ignoring journalled data option");
1755 			else if (test_opt(sb, DATA_FLAGS) != m->mount_opt) {
1756 				ext4_msg(sb, KERN_ERR,
1757 					 "Cannot change data mode on remount");
1758 				return -1;
1759 			}
1760 		} else {
1761 			clear_opt(sb, DATA_FLAGS);
1762 			sbi->s_mount_opt |= m->mount_opt;
1763 		}
1764 #ifdef CONFIG_QUOTA
1765 	} else if (m->flags & MOPT_QFMT) {
1766 		if (sb_any_quota_loaded(sb) &&
1767 		    sbi->s_jquota_fmt != m->mount_opt) {
1768 			ext4_msg(sb, KERN_ERR, "Cannot change journaled "
1769 				 "quota options when quota turned on");
1770 			return -1;
1771 		}
1772 		if (ext4_has_feature_quota(sb)) {
1773 			ext4_msg(sb, KERN_INFO,
1774 				 "Quota format mount options ignored "
1775 				 "when QUOTA feature is enabled");
1776 			return 1;
1777 		}
1778 		sbi->s_jquota_fmt = m->mount_opt;
1779 #endif
1780 	} else if (token == Opt_dax) {
1781 #ifdef CONFIG_FS_DAX
1782 		ext4_msg(sb, KERN_WARNING,
1783 		"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
1784 			sbi->s_mount_opt |= m->mount_opt;
1785 #else
1786 		ext4_msg(sb, KERN_INFO, "dax option not supported");
1787 		return -1;
1788 #endif
1789 	} else if (token == Opt_data_err_abort) {
1790 		sbi->s_mount_opt |= m->mount_opt;
1791 	} else if (token == Opt_data_err_ignore) {
1792 		sbi->s_mount_opt &= ~m->mount_opt;
1793 	} else {
1794 		if (!args->from)
1795 			arg = 1;
1796 		if (m->flags & MOPT_CLEAR)
1797 			arg = !arg;
1798 		else if (unlikely(!(m->flags & MOPT_SET))) {
1799 			ext4_msg(sb, KERN_WARNING,
1800 				 "buggy handling of option %s", opt);
1801 			WARN_ON(1);
1802 			return -1;
1803 		}
1804 		if (arg != 0)
1805 			sbi->s_mount_opt |= m->mount_opt;
1806 		else
1807 			sbi->s_mount_opt &= ~m->mount_opt;
1808 	}
1809 	return 1;
1810 }
1811 
1812 static int parse_options(char *options, struct super_block *sb,
1813 			 unsigned long *journal_devnum,
1814 			 unsigned int *journal_ioprio,
1815 			 int is_remount)
1816 {
1817 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1818 	char *p;
1819 	substring_t args[MAX_OPT_ARGS];
1820 	int token;
1821 
1822 	if (!options)
1823 		return 1;
1824 
1825 	while ((p = strsep(&options, ",")) != NULL) {
1826 		if (!*p)
1827 			continue;
1828 		/*
1829 		 * Initialize args struct so we know whether arg was
1830 		 * found; some options take optional arguments.
1831 		 */
1832 		args[0].to = args[0].from = NULL;
1833 		token = match_token(p, tokens, args);
1834 		if (handle_mount_opt(sb, p, token, args, journal_devnum,
1835 				     journal_ioprio, is_remount) < 0)
1836 			return 0;
1837 	}
1838 #ifdef CONFIG_QUOTA
1839 	if (ext4_has_feature_quota(sb) &&
1840 	    (test_opt(sb, USRQUOTA) || test_opt(sb, GRPQUOTA))) {
1841 		ext4_msg(sb, KERN_INFO, "Quota feature enabled, usrquota and grpquota "
1842 			 "mount options ignored.");
1843 		clear_opt(sb, USRQUOTA);
1844 		clear_opt(sb, GRPQUOTA);
1845 	} else if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
1846 		if (test_opt(sb, USRQUOTA) && sbi->s_qf_names[USRQUOTA])
1847 			clear_opt(sb, USRQUOTA);
1848 
1849 		if (test_opt(sb, GRPQUOTA) && sbi->s_qf_names[GRPQUOTA])
1850 			clear_opt(sb, GRPQUOTA);
1851 
1852 		if (test_opt(sb, GRPQUOTA) || test_opt(sb, USRQUOTA)) {
1853 			ext4_msg(sb, KERN_ERR, "old and new quota "
1854 					"format mixing");
1855 			return 0;
1856 		}
1857 
1858 		if (!sbi->s_jquota_fmt) {
1859 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1860 					"not specified");
1861 			return 0;
1862 		}
1863 	}
1864 #endif
1865 	if (test_opt(sb, DIOREAD_NOLOCK)) {
1866 		int blocksize =
1867 			BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
1868 
1869 		if (blocksize < PAGE_SIZE) {
1870 			ext4_msg(sb, KERN_ERR, "can't mount with "
1871 				 "dioread_nolock if block size != PAGE_SIZE");
1872 			return 0;
1873 		}
1874 	}
1875 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA &&
1876 	    test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
1877 		ext4_msg(sb, KERN_ERR, "can't mount with journal_async_commit "
1878 			 "in data=ordered mode");
1879 		return 0;
1880 	}
1881 	return 1;
1882 }
1883 
1884 static inline void ext4_show_quota_options(struct seq_file *seq,
1885 					   struct super_block *sb)
1886 {
1887 #if defined(CONFIG_QUOTA)
1888 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1889 
1890 	if (sbi->s_jquota_fmt) {
1891 		char *fmtname = "";
1892 
1893 		switch (sbi->s_jquota_fmt) {
1894 		case QFMT_VFS_OLD:
1895 			fmtname = "vfsold";
1896 			break;
1897 		case QFMT_VFS_V0:
1898 			fmtname = "vfsv0";
1899 			break;
1900 		case QFMT_VFS_V1:
1901 			fmtname = "vfsv1";
1902 			break;
1903 		}
1904 		seq_printf(seq, ",jqfmt=%s", fmtname);
1905 	}
1906 
1907 	if (sbi->s_qf_names[USRQUOTA])
1908 		seq_show_option(seq, "usrjquota", sbi->s_qf_names[USRQUOTA]);
1909 
1910 	if (sbi->s_qf_names[GRPQUOTA])
1911 		seq_show_option(seq, "grpjquota", sbi->s_qf_names[GRPQUOTA]);
1912 #endif
1913 }
1914 
1915 static const char *token2str(int token)
1916 {
1917 	const struct match_token *t;
1918 
1919 	for (t = tokens; t->token != Opt_err; t++)
1920 		if (t->token == token && !strchr(t->pattern, '='))
1921 			break;
1922 	return t->pattern;
1923 }
1924 
1925 /*
1926  * Show an option if
1927  *  - it's set to a non-default value OR
1928  *  - if the per-sb default is different from the global default
1929  */
1930 static int _ext4_show_options(struct seq_file *seq, struct super_block *sb,
1931 			      int nodefs)
1932 {
1933 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1934 	struct ext4_super_block *es = sbi->s_es;
1935 	int def_errors, def_mount_opt = nodefs ? 0 : sbi->s_def_mount_opt;
1936 	const struct mount_opts *m;
1937 	char sep = nodefs ? '\n' : ',';
1938 
1939 #define SEQ_OPTS_PUTS(str) seq_printf(seq, "%c" str, sep)
1940 #define SEQ_OPTS_PRINT(str, arg) seq_printf(seq, "%c" str, sep, arg)
1941 
1942 	if (sbi->s_sb_block != 1)
1943 		SEQ_OPTS_PRINT("sb=%llu", sbi->s_sb_block);
1944 
1945 	for (m = ext4_mount_opts; m->token != Opt_err; m++) {
1946 		int want_set = m->flags & MOPT_SET;
1947 		if (((m->flags & (MOPT_SET|MOPT_CLEAR)) == 0) ||
1948 		    (m->flags & MOPT_CLEAR_ERR))
1949 			continue;
1950 		if (!(m->mount_opt & (sbi->s_mount_opt ^ def_mount_opt)))
1951 			continue; /* skip if same as the default */
1952 		if ((want_set &&
1953 		     (sbi->s_mount_opt & m->mount_opt) != m->mount_opt) ||
1954 		    (!want_set && (sbi->s_mount_opt & m->mount_opt)))
1955 			continue; /* select Opt_noFoo vs Opt_Foo */
1956 		SEQ_OPTS_PRINT("%s", token2str(m->token));
1957 	}
1958 
1959 	if (nodefs || !uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT4_DEF_RESUID)) ||
1960 	    le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID)
1961 		SEQ_OPTS_PRINT("resuid=%u",
1962 				from_kuid_munged(&init_user_ns, sbi->s_resuid));
1963 	if (nodefs || !gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT4_DEF_RESGID)) ||
1964 	    le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID)
1965 		SEQ_OPTS_PRINT("resgid=%u",
1966 				from_kgid_munged(&init_user_ns, sbi->s_resgid));
1967 	def_errors = nodefs ? -1 : le16_to_cpu(es->s_errors);
1968 	if (test_opt(sb, ERRORS_RO) && def_errors != EXT4_ERRORS_RO)
1969 		SEQ_OPTS_PUTS("errors=remount-ro");
1970 	if (test_opt(sb, ERRORS_CONT) && def_errors != EXT4_ERRORS_CONTINUE)
1971 		SEQ_OPTS_PUTS("errors=continue");
1972 	if (test_opt(sb, ERRORS_PANIC) && def_errors != EXT4_ERRORS_PANIC)
1973 		SEQ_OPTS_PUTS("errors=panic");
1974 	if (nodefs || sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ)
1975 		SEQ_OPTS_PRINT("commit=%lu", sbi->s_commit_interval / HZ);
1976 	if (nodefs || sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME)
1977 		SEQ_OPTS_PRINT("min_batch_time=%u", sbi->s_min_batch_time);
1978 	if (nodefs || sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME)
1979 		SEQ_OPTS_PRINT("max_batch_time=%u", sbi->s_max_batch_time);
1980 	if (sb->s_flags & MS_I_VERSION)
1981 		SEQ_OPTS_PUTS("i_version");
1982 	if (nodefs || sbi->s_stripe)
1983 		SEQ_OPTS_PRINT("stripe=%lu", sbi->s_stripe);
1984 	if (EXT4_MOUNT_DATA_FLAGS & (sbi->s_mount_opt ^ def_mount_opt)) {
1985 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
1986 			SEQ_OPTS_PUTS("data=journal");
1987 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
1988 			SEQ_OPTS_PUTS("data=ordered");
1989 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
1990 			SEQ_OPTS_PUTS("data=writeback");
1991 	}
1992 	if (nodefs ||
1993 	    sbi->s_inode_readahead_blks != EXT4_DEF_INODE_READAHEAD_BLKS)
1994 		SEQ_OPTS_PRINT("inode_readahead_blks=%u",
1995 			       sbi->s_inode_readahead_blks);
1996 
1997 	if (nodefs || (test_opt(sb, INIT_INODE_TABLE) &&
1998 		       (sbi->s_li_wait_mult != EXT4_DEF_LI_WAIT_MULT)))
1999 		SEQ_OPTS_PRINT("init_itable=%u", sbi->s_li_wait_mult);
2000 	if (nodefs || sbi->s_max_dir_size_kb)
2001 		SEQ_OPTS_PRINT("max_dir_size_kb=%u", sbi->s_max_dir_size_kb);
2002 	if (test_opt(sb, DATA_ERR_ABORT))
2003 		SEQ_OPTS_PUTS("data_err=abort");
2004 
2005 	ext4_show_quota_options(seq, sb);
2006 	return 0;
2007 }
2008 
2009 static int ext4_show_options(struct seq_file *seq, struct dentry *root)
2010 {
2011 	return _ext4_show_options(seq, root->d_sb, 0);
2012 }
2013 
2014 int ext4_seq_options_show(struct seq_file *seq, void *offset)
2015 {
2016 	struct super_block *sb = seq->private;
2017 	int rc;
2018 
2019 	seq_puts(seq, (sb->s_flags & MS_RDONLY) ? "ro" : "rw");
2020 	rc = _ext4_show_options(seq, sb, 1);
2021 	seq_puts(seq, "\n");
2022 	return rc;
2023 }
2024 
2025 static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
2026 			    int read_only)
2027 {
2028 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2029 	int res = 0;
2030 
2031 	if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
2032 		ext4_msg(sb, KERN_ERR, "revision level too high, "
2033 			 "forcing read-only mode");
2034 		res = MS_RDONLY;
2035 	}
2036 	if (read_only)
2037 		goto done;
2038 	if (!(sbi->s_mount_state & EXT4_VALID_FS))
2039 		ext4_msg(sb, KERN_WARNING, "warning: mounting unchecked fs, "
2040 			 "running e2fsck is recommended");
2041 	else if (sbi->s_mount_state & EXT4_ERROR_FS)
2042 		ext4_msg(sb, KERN_WARNING,
2043 			 "warning: mounting fs with errors, "
2044 			 "running e2fsck is recommended");
2045 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) > 0 &&
2046 		 le16_to_cpu(es->s_mnt_count) >=
2047 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
2048 		ext4_msg(sb, KERN_WARNING,
2049 			 "warning: maximal mount count reached, "
2050 			 "running e2fsck is recommended");
2051 	else if (le32_to_cpu(es->s_checkinterval) &&
2052 		(le32_to_cpu(es->s_lastcheck) +
2053 			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
2054 		ext4_msg(sb, KERN_WARNING,
2055 			 "warning: checktime reached, "
2056 			 "running e2fsck is recommended");
2057 	if (!sbi->s_journal)
2058 		es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
2059 	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
2060 		es->s_max_mnt_count = cpu_to_le16(EXT4_DFL_MAX_MNT_COUNT);
2061 	le16_add_cpu(&es->s_mnt_count, 1);
2062 	es->s_mtime = cpu_to_le32(get_seconds());
2063 	ext4_update_dynamic_rev(sb);
2064 	if (sbi->s_journal)
2065 		ext4_set_feature_journal_needs_recovery(sb);
2066 
2067 	ext4_commit_super(sb, 1);
2068 done:
2069 	if (test_opt(sb, DEBUG))
2070 		printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, "
2071 				"bpg=%lu, ipg=%lu, mo=%04x, mo2=%04x]\n",
2072 			sb->s_blocksize,
2073 			sbi->s_groups_count,
2074 			EXT4_BLOCKS_PER_GROUP(sb),
2075 			EXT4_INODES_PER_GROUP(sb),
2076 			sbi->s_mount_opt, sbi->s_mount_opt2);
2077 
2078 	cleancache_init_fs(sb);
2079 	return res;
2080 }
2081 
2082 int ext4_alloc_flex_bg_array(struct super_block *sb, ext4_group_t ngroup)
2083 {
2084 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2085 	struct flex_groups *new_groups;
2086 	int size;
2087 
2088 	if (!sbi->s_log_groups_per_flex)
2089 		return 0;
2090 
2091 	size = ext4_flex_group(sbi, ngroup - 1) + 1;
2092 	if (size <= sbi->s_flex_groups_allocated)
2093 		return 0;
2094 
2095 	size = roundup_pow_of_two(size * sizeof(struct flex_groups));
2096 	new_groups = ext4_kvzalloc(size, GFP_KERNEL);
2097 	if (!new_groups) {
2098 		ext4_msg(sb, KERN_ERR, "not enough memory for %d flex groups",
2099 			 size / (int) sizeof(struct flex_groups));
2100 		return -ENOMEM;
2101 	}
2102 
2103 	if (sbi->s_flex_groups) {
2104 		memcpy(new_groups, sbi->s_flex_groups,
2105 		       (sbi->s_flex_groups_allocated *
2106 			sizeof(struct flex_groups)));
2107 		kvfree(sbi->s_flex_groups);
2108 	}
2109 	sbi->s_flex_groups = new_groups;
2110 	sbi->s_flex_groups_allocated = size / sizeof(struct flex_groups);
2111 	return 0;
2112 }
2113 
2114 static int ext4_fill_flex_info(struct super_block *sb)
2115 {
2116 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2117 	struct ext4_group_desc *gdp = NULL;
2118 	ext4_group_t flex_group;
2119 	int i, err;
2120 
2121 	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
2122 	if (sbi->s_log_groups_per_flex < 1 || sbi->s_log_groups_per_flex > 31) {
2123 		sbi->s_log_groups_per_flex = 0;
2124 		return 1;
2125 	}
2126 
2127 	err = ext4_alloc_flex_bg_array(sb, sbi->s_groups_count);
2128 	if (err)
2129 		goto failed;
2130 
2131 	for (i = 0; i < sbi->s_groups_count; i++) {
2132 		gdp = ext4_get_group_desc(sb, i, NULL);
2133 
2134 		flex_group = ext4_flex_group(sbi, i);
2135 		atomic_add(ext4_free_inodes_count(sb, gdp),
2136 			   &sbi->s_flex_groups[flex_group].free_inodes);
2137 		atomic64_add(ext4_free_group_clusters(sb, gdp),
2138 			     &sbi->s_flex_groups[flex_group].free_clusters);
2139 		atomic_add(ext4_used_dirs_count(sb, gdp),
2140 			   &sbi->s_flex_groups[flex_group].used_dirs);
2141 	}
2142 
2143 	return 1;
2144 failed:
2145 	return 0;
2146 }
2147 
2148 static __le16 ext4_group_desc_csum(struct super_block *sb, __u32 block_group,
2149 				   struct ext4_group_desc *gdp)
2150 {
2151 	int offset = offsetof(struct ext4_group_desc, bg_checksum);
2152 	__u16 crc = 0;
2153 	__le32 le_group = cpu_to_le32(block_group);
2154 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2155 
2156 	if (ext4_has_metadata_csum(sbi->s_sb)) {
2157 		/* Use new metadata_csum algorithm */
2158 		__u32 csum32;
2159 		__u16 dummy_csum = 0;
2160 
2161 		csum32 = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&le_group,
2162 				     sizeof(le_group));
2163 		csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp, offset);
2164 		csum32 = ext4_chksum(sbi, csum32, (__u8 *)&dummy_csum,
2165 				     sizeof(dummy_csum));
2166 		offset += sizeof(dummy_csum);
2167 		if (offset < sbi->s_desc_size)
2168 			csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp + offset,
2169 					     sbi->s_desc_size - offset);
2170 
2171 		crc = csum32 & 0xFFFF;
2172 		goto out;
2173 	}
2174 
2175 	/* old crc16 code */
2176 	if (!ext4_has_feature_gdt_csum(sb))
2177 		return 0;
2178 
2179 	crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
2180 	crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
2181 	crc = crc16(crc, (__u8 *)gdp, offset);
2182 	offset += sizeof(gdp->bg_checksum); /* skip checksum */
2183 	/* for checksum of struct ext4_group_desc do the rest...*/
2184 	if (ext4_has_feature_64bit(sb) &&
2185 	    offset < le16_to_cpu(sbi->s_es->s_desc_size))
2186 		crc = crc16(crc, (__u8 *)gdp + offset,
2187 			    le16_to_cpu(sbi->s_es->s_desc_size) -
2188 				offset);
2189 
2190 out:
2191 	return cpu_to_le16(crc);
2192 }
2193 
2194 int ext4_group_desc_csum_verify(struct super_block *sb, __u32 block_group,
2195 				struct ext4_group_desc *gdp)
2196 {
2197 	if (ext4_has_group_desc_csum(sb) &&
2198 	    (gdp->bg_checksum != ext4_group_desc_csum(sb, block_group, gdp)))
2199 		return 0;
2200 
2201 	return 1;
2202 }
2203 
2204 void ext4_group_desc_csum_set(struct super_block *sb, __u32 block_group,
2205 			      struct ext4_group_desc *gdp)
2206 {
2207 	if (!ext4_has_group_desc_csum(sb))
2208 		return;
2209 	gdp->bg_checksum = ext4_group_desc_csum(sb, block_group, gdp);
2210 }
2211 
2212 /* Called at mount-time, super-block is locked */
2213 static int ext4_check_descriptors(struct super_block *sb,
2214 				  ext4_fsblk_t sb_block,
2215 				  ext4_group_t *first_not_zeroed)
2216 {
2217 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2218 	ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
2219 	ext4_fsblk_t last_block;
2220 	ext4_fsblk_t block_bitmap;
2221 	ext4_fsblk_t inode_bitmap;
2222 	ext4_fsblk_t inode_table;
2223 	int flexbg_flag = 0;
2224 	ext4_group_t i, grp = sbi->s_groups_count;
2225 
2226 	if (ext4_has_feature_flex_bg(sb))
2227 		flexbg_flag = 1;
2228 
2229 	ext4_debug("Checking group descriptors");
2230 
2231 	for (i = 0; i < sbi->s_groups_count; i++) {
2232 		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
2233 
2234 		if (i == sbi->s_groups_count - 1 || flexbg_flag)
2235 			last_block = ext4_blocks_count(sbi->s_es) - 1;
2236 		else
2237 			last_block = first_block +
2238 				(EXT4_BLOCKS_PER_GROUP(sb) - 1);
2239 
2240 		if ((grp == sbi->s_groups_count) &&
2241 		   !(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2242 			grp = i;
2243 
2244 		block_bitmap = ext4_block_bitmap(sb, gdp);
2245 		if (block_bitmap == sb_block) {
2246 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2247 				 "Block bitmap for group %u overlaps "
2248 				 "superblock", i);
2249 		}
2250 		if (block_bitmap < first_block || block_bitmap > last_block) {
2251 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2252 			       "Block bitmap for group %u not in group "
2253 			       "(block %llu)!", i, block_bitmap);
2254 			return 0;
2255 		}
2256 		inode_bitmap = ext4_inode_bitmap(sb, gdp);
2257 		if (inode_bitmap == sb_block) {
2258 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2259 				 "Inode bitmap for group %u overlaps "
2260 				 "superblock", i);
2261 		}
2262 		if (inode_bitmap < first_block || inode_bitmap > last_block) {
2263 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2264 			       "Inode bitmap for group %u not in group "
2265 			       "(block %llu)!", i, inode_bitmap);
2266 			return 0;
2267 		}
2268 		inode_table = ext4_inode_table(sb, gdp);
2269 		if (inode_table == sb_block) {
2270 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2271 				 "Inode table for group %u overlaps "
2272 				 "superblock", i);
2273 		}
2274 		if (inode_table < first_block ||
2275 		    inode_table + sbi->s_itb_per_group - 1 > last_block) {
2276 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2277 			       "Inode table for group %u not in group "
2278 			       "(block %llu)!", i, inode_table);
2279 			return 0;
2280 		}
2281 		ext4_lock_group(sb, i);
2282 		if (!ext4_group_desc_csum_verify(sb, i, gdp)) {
2283 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2284 				 "Checksum for group %u failed (%u!=%u)",
2285 				 i, le16_to_cpu(ext4_group_desc_csum(sb, i,
2286 				     gdp)), le16_to_cpu(gdp->bg_checksum));
2287 			if (!(sb->s_flags & MS_RDONLY)) {
2288 				ext4_unlock_group(sb, i);
2289 				return 0;
2290 			}
2291 		}
2292 		ext4_unlock_group(sb, i);
2293 		if (!flexbg_flag)
2294 			first_block += EXT4_BLOCKS_PER_GROUP(sb);
2295 	}
2296 	if (NULL != first_not_zeroed)
2297 		*first_not_zeroed = grp;
2298 	return 1;
2299 }
2300 
2301 /* ext4_orphan_cleanup() walks a singly-linked list of inodes (starting at
2302  * the superblock) which were deleted from all directories, but held open by
2303  * a process at the time of a crash.  We walk the list and try to delete these
2304  * inodes at recovery time (only with a read-write filesystem).
2305  *
2306  * In order to keep the orphan inode chain consistent during traversal (in
2307  * case of crash during recovery), we link each inode into the superblock
2308  * orphan list_head and handle it the same way as an inode deletion during
2309  * normal operation (which journals the operations for us).
2310  *
2311  * We only do an iget() and an iput() on each inode, which is very safe if we
2312  * accidentally point at an in-use or already deleted inode.  The worst that
2313  * can happen in this case is that we get a "bit already cleared" message from
2314  * ext4_free_inode().  The only reason we would point at a wrong inode is if
2315  * e2fsck was run on this filesystem, and it must have already done the orphan
2316  * inode cleanup for us, so we can safely abort without any further action.
2317  */
2318 static void ext4_orphan_cleanup(struct super_block *sb,
2319 				struct ext4_super_block *es)
2320 {
2321 	unsigned int s_flags = sb->s_flags;
2322 	int nr_orphans = 0, nr_truncates = 0;
2323 #ifdef CONFIG_QUOTA
2324 	int i;
2325 #endif
2326 	if (!es->s_last_orphan) {
2327 		jbd_debug(4, "no orphan inodes to clean up\n");
2328 		return;
2329 	}
2330 
2331 	if (bdev_read_only(sb->s_bdev)) {
2332 		ext4_msg(sb, KERN_ERR, "write access "
2333 			"unavailable, skipping orphan cleanup");
2334 		return;
2335 	}
2336 
2337 	/* Check if feature set would not allow a r/w mount */
2338 	if (!ext4_feature_set_ok(sb, 0)) {
2339 		ext4_msg(sb, KERN_INFO, "Skipping orphan cleanup due to "
2340 			 "unknown ROCOMPAT features");
2341 		return;
2342 	}
2343 
2344 	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
2345 		/* don't clear list on RO mount w/ errors */
2346 		if (es->s_last_orphan && !(s_flags & MS_RDONLY)) {
2347 			ext4_msg(sb, KERN_INFO, "Errors on filesystem, "
2348 				  "clearing orphan list.\n");
2349 			es->s_last_orphan = 0;
2350 		}
2351 		jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
2352 		return;
2353 	}
2354 
2355 	if (s_flags & MS_RDONLY) {
2356 		ext4_msg(sb, KERN_INFO, "orphan cleanup on readonly fs");
2357 		sb->s_flags &= ~MS_RDONLY;
2358 	}
2359 #ifdef CONFIG_QUOTA
2360 	/* Needed for iput() to work correctly and not trash data */
2361 	sb->s_flags |= MS_ACTIVE;
2362 	/* Turn on quotas so that they are updated correctly */
2363 	for (i = 0; i < EXT4_MAXQUOTAS; i++) {
2364 		if (EXT4_SB(sb)->s_qf_names[i]) {
2365 			int ret = ext4_quota_on_mount(sb, i);
2366 			if (ret < 0)
2367 				ext4_msg(sb, KERN_ERR,
2368 					"Cannot turn on journaled "
2369 					"quota: error %d", ret);
2370 		}
2371 	}
2372 #endif
2373 
2374 	while (es->s_last_orphan) {
2375 		struct inode *inode;
2376 
2377 		/*
2378 		 * We may have encountered an error during cleanup; if
2379 		 * so, skip the rest.
2380 		 */
2381 		if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
2382 			jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
2383 			es->s_last_orphan = 0;
2384 			break;
2385 		}
2386 
2387 		inode = ext4_orphan_get(sb, le32_to_cpu(es->s_last_orphan));
2388 		if (IS_ERR(inode)) {
2389 			es->s_last_orphan = 0;
2390 			break;
2391 		}
2392 
2393 		list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
2394 		dquot_initialize(inode);
2395 		if (inode->i_nlink) {
2396 			if (test_opt(sb, DEBUG))
2397 				ext4_msg(sb, KERN_DEBUG,
2398 					"%s: truncating inode %lu to %lld bytes",
2399 					__func__, inode->i_ino, inode->i_size);
2400 			jbd_debug(2, "truncating inode %lu to %lld bytes\n",
2401 				  inode->i_ino, inode->i_size);
2402 			inode_lock(inode);
2403 			truncate_inode_pages(inode->i_mapping, inode->i_size);
2404 			ext4_truncate(inode);
2405 			inode_unlock(inode);
2406 			nr_truncates++;
2407 		} else {
2408 			if (test_opt(sb, DEBUG))
2409 				ext4_msg(sb, KERN_DEBUG,
2410 					"%s: deleting unreferenced inode %lu",
2411 					__func__, inode->i_ino);
2412 			jbd_debug(2, "deleting unreferenced inode %lu\n",
2413 				  inode->i_ino);
2414 			nr_orphans++;
2415 		}
2416 		iput(inode);  /* The delete magic happens here! */
2417 	}
2418 
2419 #define PLURAL(x) (x), ((x) == 1) ? "" : "s"
2420 
2421 	if (nr_orphans)
2422 		ext4_msg(sb, KERN_INFO, "%d orphan inode%s deleted",
2423 		       PLURAL(nr_orphans));
2424 	if (nr_truncates)
2425 		ext4_msg(sb, KERN_INFO, "%d truncate%s cleaned up",
2426 		       PLURAL(nr_truncates));
2427 #ifdef CONFIG_QUOTA
2428 	/* Turn quotas off */
2429 	for (i = 0; i < EXT4_MAXQUOTAS; i++) {
2430 		if (sb_dqopt(sb)->files[i])
2431 			dquot_quota_off(sb, i);
2432 	}
2433 #endif
2434 	sb->s_flags = s_flags; /* Restore MS_RDONLY status */
2435 }
2436 
2437 /*
2438  * Maximal extent format file size.
2439  * Resulting logical blkno at s_maxbytes must fit in our on-disk
2440  * extent format containers, within a sector_t, and within i_blocks
2441  * in the vfs.  ext4 inode has 48 bits of i_block in fsblock units,
2442  * so that won't be a limiting factor.
2443  *
2444  * However there is other limiting factor. We do store extents in the form
2445  * of starting block and length, hence the resulting length of the extent
2446  * covering maximum file size must fit into on-disk format containers as
2447  * well. Given that length is always by 1 unit bigger than max unit (because
2448  * we count 0 as well) we have to lower the s_maxbytes by one fs block.
2449  *
2450  * Note, this does *not* consider any metadata overhead for vfs i_blocks.
2451  */
2452 static loff_t ext4_max_size(int blkbits, int has_huge_files)
2453 {
2454 	loff_t res;
2455 	loff_t upper_limit = MAX_LFS_FILESIZE;
2456 
2457 	/* small i_blocks in vfs inode? */
2458 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2459 		/*
2460 		 * CONFIG_LBDAF is not enabled implies the inode
2461 		 * i_block represent total blocks in 512 bytes
2462 		 * 32 == size of vfs inode i_blocks * 8
2463 		 */
2464 		upper_limit = (1LL << 32) - 1;
2465 
2466 		/* total blocks in file system block size */
2467 		upper_limit >>= (blkbits - 9);
2468 		upper_limit <<= blkbits;
2469 	}
2470 
2471 	/*
2472 	 * 32-bit extent-start container, ee_block. We lower the maxbytes
2473 	 * by one fs block, so ee_len can cover the extent of maximum file
2474 	 * size
2475 	 */
2476 	res = (1LL << 32) - 1;
2477 	res <<= blkbits;
2478 
2479 	/* Sanity check against vm- & vfs- imposed limits */
2480 	if (res > upper_limit)
2481 		res = upper_limit;
2482 
2483 	return res;
2484 }
2485 
2486 /*
2487  * Maximal bitmap file size.  There is a direct, and {,double-,triple-}indirect
2488  * block limit, and also a limit of (2^48 - 1) 512-byte sectors in i_blocks.
2489  * We need to be 1 filesystem block less than the 2^48 sector limit.
2490  */
2491 static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
2492 {
2493 	loff_t res = EXT4_NDIR_BLOCKS;
2494 	int meta_blocks;
2495 	loff_t upper_limit;
2496 	/* This is calculated to be the largest file size for a dense, block
2497 	 * mapped file such that the file's total number of 512-byte sectors,
2498 	 * including data and all indirect blocks, does not exceed (2^48 - 1).
2499 	 *
2500 	 * __u32 i_blocks_lo and _u16 i_blocks_high represent the total
2501 	 * number of 512-byte sectors of the file.
2502 	 */
2503 
2504 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2505 		/*
2506 		 * !has_huge_files or CONFIG_LBDAF not enabled implies that
2507 		 * the inode i_block field represents total file blocks in
2508 		 * 2^32 512-byte sectors == size of vfs inode i_blocks * 8
2509 		 */
2510 		upper_limit = (1LL << 32) - 1;
2511 
2512 		/* total blocks in file system block size */
2513 		upper_limit >>= (bits - 9);
2514 
2515 	} else {
2516 		/*
2517 		 * We use 48 bit ext4_inode i_blocks
2518 		 * With EXT4_HUGE_FILE_FL set the i_blocks
2519 		 * represent total number of blocks in
2520 		 * file system block size
2521 		 */
2522 		upper_limit = (1LL << 48) - 1;
2523 
2524 	}
2525 
2526 	/* indirect blocks */
2527 	meta_blocks = 1;
2528 	/* double indirect blocks */
2529 	meta_blocks += 1 + (1LL << (bits-2));
2530 	/* tripple indirect blocks */
2531 	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
2532 
2533 	upper_limit -= meta_blocks;
2534 	upper_limit <<= bits;
2535 
2536 	res += 1LL << (bits-2);
2537 	res += 1LL << (2*(bits-2));
2538 	res += 1LL << (3*(bits-2));
2539 	res <<= bits;
2540 	if (res > upper_limit)
2541 		res = upper_limit;
2542 
2543 	if (res > MAX_LFS_FILESIZE)
2544 		res = MAX_LFS_FILESIZE;
2545 
2546 	return res;
2547 }
2548 
2549 static ext4_fsblk_t descriptor_loc(struct super_block *sb,
2550 				   ext4_fsblk_t logical_sb_block, int nr)
2551 {
2552 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2553 	ext4_group_t bg, first_meta_bg;
2554 	int has_super = 0;
2555 
2556 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
2557 
2558 	if (!ext4_has_feature_meta_bg(sb) || nr < first_meta_bg)
2559 		return logical_sb_block + nr + 1;
2560 	bg = sbi->s_desc_per_block * nr;
2561 	if (ext4_bg_has_super(sb, bg))
2562 		has_super = 1;
2563 
2564 	/*
2565 	 * If we have a meta_bg fs with 1k blocks, group 0's GDT is at
2566 	 * block 2, not 1.  If s_first_data_block == 0 (bigalloc is enabled
2567 	 * on modern mke2fs or blksize > 1k on older mke2fs) then we must
2568 	 * compensate.
2569 	 */
2570 	if (sb->s_blocksize == 1024 && nr == 0 &&
2571 	    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block) == 0)
2572 		has_super++;
2573 
2574 	return (has_super + ext4_group_first_block_no(sb, bg));
2575 }
2576 
2577 /**
2578  * ext4_get_stripe_size: Get the stripe size.
2579  * @sbi: In memory super block info
2580  *
2581  * If we have specified it via mount option, then
2582  * use the mount option value. If the value specified at mount time is
2583  * greater than the blocks per group use the super block value.
2584  * If the super block value is greater than blocks per group return 0.
2585  * Allocator needs it be less than blocks per group.
2586  *
2587  */
2588 static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi)
2589 {
2590 	unsigned long stride = le16_to_cpu(sbi->s_es->s_raid_stride);
2591 	unsigned long stripe_width =
2592 			le32_to_cpu(sbi->s_es->s_raid_stripe_width);
2593 	int ret;
2594 
2595 	if (sbi->s_stripe && sbi->s_stripe <= sbi->s_blocks_per_group)
2596 		ret = sbi->s_stripe;
2597 	else if (stripe_width <= sbi->s_blocks_per_group)
2598 		ret = stripe_width;
2599 	else if (stride <= sbi->s_blocks_per_group)
2600 		ret = stride;
2601 	else
2602 		ret = 0;
2603 
2604 	/*
2605 	 * If the stripe width is 1, this makes no sense and
2606 	 * we set it to 0 to turn off stripe handling code.
2607 	 */
2608 	if (ret <= 1)
2609 		ret = 0;
2610 
2611 	return ret;
2612 }
2613 
2614 /*
2615  * Check whether this filesystem can be mounted based on
2616  * the features present and the RDONLY/RDWR mount requested.
2617  * Returns 1 if this filesystem can be mounted as requested,
2618  * 0 if it cannot be.
2619  */
2620 static int ext4_feature_set_ok(struct super_block *sb, int readonly)
2621 {
2622 	if (ext4_has_unknown_ext4_incompat_features(sb)) {
2623 		ext4_msg(sb, KERN_ERR,
2624 			"Couldn't mount because of "
2625 			"unsupported optional features (%x)",
2626 			(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_incompat) &
2627 			~EXT4_FEATURE_INCOMPAT_SUPP));
2628 		return 0;
2629 	}
2630 
2631 	if (readonly)
2632 		return 1;
2633 
2634 	if (ext4_has_feature_readonly(sb)) {
2635 		ext4_msg(sb, KERN_INFO, "filesystem is read-only");
2636 		sb->s_flags |= MS_RDONLY;
2637 		return 1;
2638 	}
2639 
2640 	/* Check that feature set is OK for a read-write mount */
2641 	if (ext4_has_unknown_ext4_ro_compat_features(sb)) {
2642 		ext4_msg(sb, KERN_ERR, "couldn't mount RDWR because of "
2643 			 "unsupported optional features (%x)",
2644 			 (le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_ro_compat) &
2645 				~EXT4_FEATURE_RO_COMPAT_SUPP));
2646 		return 0;
2647 	}
2648 	/*
2649 	 * Large file size enabled file system can only be mounted
2650 	 * read-write on 32-bit systems if kernel is built with CONFIG_LBDAF
2651 	 */
2652 	if (ext4_has_feature_huge_file(sb)) {
2653 		if (sizeof(blkcnt_t) < sizeof(u64)) {
2654 			ext4_msg(sb, KERN_ERR, "Filesystem with huge files "
2655 				 "cannot be mounted RDWR without "
2656 				 "CONFIG_LBDAF");
2657 			return 0;
2658 		}
2659 	}
2660 	if (ext4_has_feature_bigalloc(sb) && !ext4_has_feature_extents(sb)) {
2661 		ext4_msg(sb, KERN_ERR,
2662 			 "Can't support bigalloc feature without "
2663 			 "extents feature\n");
2664 		return 0;
2665 	}
2666 
2667 #ifndef CONFIG_QUOTA
2668 	if (ext4_has_feature_quota(sb) && !readonly) {
2669 		ext4_msg(sb, KERN_ERR,
2670 			 "Filesystem with quota feature cannot be mounted RDWR "
2671 			 "without CONFIG_QUOTA");
2672 		return 0;
2673 	}
2674 	if (ext4_has_feature_project(sb) && !readonly) {
2675 		ext4_msg(sb, KERN_ERR,
2676 			 "Filesystem with project quota feature cannot be mounted RDWR "
2677 			 "without CONFIG_QUOTA");
2678 		return 0;
2679 	}
2680 #endif  /* CONFIG_QUOTA */
2681 	return 1;
2682 }
2683 
2684 /*
2685  * This function is called once a day if we have errors logged
2686  * on the file system
2687  */
2688 static void print_daily_error_info(unsigned long arg)
2689 {
2690 	struct super_block *sb = (struct super_block *) arg;
2691 	struct ext4_sb_info *sbi;
2692 	struct ext4_super_block *es;
2693 
2694 	sbi = EXT4_SB(sb);
2695 	es = sbi->s_es;
2696 
2697 	if (es->s_error_count)
2698 		/* fsck newer than v1.41.13 is needed to clean this condition. */
2699 		ext4_msg(sb, KERN_NOTICE, "error count since last fsck: %u",
2700 			 le32_to_cpu(es->s_error_count));
2701 	if (es->s_first_error_time) {
2702 		printk(KERN_NOTICE "EXT4-fs (%s): initial error at time %u: %.*s:%d",
2703 		       sb->s_id, le32_to_cpu(es->s_first_error_time),
2704 		       (int) sizeof(es->s_first_error_func),
2705 		       es->s_first_error_func,
2706 		       le32_to_cpu(es->s_first_error_line));
2707 		if (es->s_first_error_ino)
2708 			printk(": inode %u",
2709 			       le32_to_cpu(es->s_first_error_ino));
2710 		if (es->s_first_error_block)
2711 			printk(": block %llu", (unsigned long long)
2712 			       le64_to_cpu(es->s_first_error_block));
2713 		printk("\n");
2714 	}
2715 	if (es->s_last_error_time) {
2716 		printk(KERN_NOTICE "EXT4-fs (%s): last error at time %u: %.*s:%d",
2717 		       sb->s_id, le32_to_cpu(es->s_last_error_time),
2718 		       (int) sizeof(es->s_last_error_func),
2719 		       es->s_last_error_func,
2720 		       le32_to_cpu(es->s_last_error_line));
2721 		if (es->s_last_error_ino)
2722 			printk(": inode %u",
2723 			       le32_to_cpu(es->s_last_error_ino));
2724 		if (es->s_last_error_block)
2725 			printk(": block %llu", (unsigned long long)
2726 			       le64_to_cpu(es->s_last_error_block));
2727 		printk("\n");
2728 	}
2729 	mod_timer(&sbi->s_err_report, jiffies + 24*60*60*HZ);  /* Once a day */
2730 }
2731 
2732 /* Find next suitable group and run ext4_init_inode_table */
2733 static int ext4_run_li_request(struct ext4_li_request *elr)
2734 {
2735 	struct ext4_group_desc *gdp = NULL;
2736 	ext4_group_t group, ngroups;
2737 	struct super_block *sb;
2738 	unsigned long timeout = 0;
2739 	int ret = 0;
2740 
2741 	sb = elr->lr_super;
2742 	ngroups = EXT4_SB(sb)->s_groups_count;
2743 
2744 	sb_start_write(sb);
2745 	for (group = elr->lr_next_group; group < ngroups; group++) {
2746 		gdp = ext4_get_group_desc(sb, group, NULL);
2747 		if (!gdp) {
2748 			ret = 1;
2749 			break;
2750 		}
2751 
2752 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2753 			break;
2754 	}
2755 
2756 	if (group >= ngroups)
2757 		ret = 1;
2758 
2759 	if (!ret) {
2760 		timeout = jiffies;
2761 		ret = ext4_init_inode_table(sb, group,
2762 					    elr->lr_timeout ? 0 : 1);
2763 		if (elr->lr_timeout == 0) {
2764 			timeout = (jiffies - timeout) *
2765 				  elr->lr_sbi->s_li_wait_mult;
2766 			elr->lr_timeout = timeout;
2767 		}
2768 		elr->lr_next_sched = jiffies + elr->lr_timeout;
2769 		elr->lr_next_group = group + 1;
2770 	}
2771 	sb_end_write(sb);
2772 
2773 	return ret;
2774 }
2775 
2776 /*
2777  * Remove lr_request from the list_request and free the
2778  * request structure. Should be called with li_list_mtx held
2779  */
2780 static void ext4_remove_li_request(struct ext4_li_request *elr)
2781 {
2782 	struct ext4_sb_info *sbi;
2783 
2784 	if (!elr)
2785 		return;
2786 
2787 	sbi = elr->lr_sbi;
2788 
2789 	list_del(&elr->lr_request);
2790 	sbi->s_li_request = NULL;
2791 	kfree(elr);
2792 }
2793 
2794 static void ext4_unregister_li_request(struct super_block *sb)
2795 {
2796 	mutex_lock(&ext4_li_mtx);
2797 	if (!ext4_li_info) {
2798 		mutex_unlock(&ext4_li_mtx);
2799 		return;
2800 	}
2801 
2802 	mutex_lock(&ext4_li_info->li_list_mtx);
2803 	ext4_remove_li_request(EXT4_SB(sb)->s_li_request);
2804 	mutex_unlock(&ext4_li_info->li_list_mtx);
2805 	mutex_unlock(&ext4_li_mtx);
2806 }
2807 
2808 static struct task_struct *ext4_lazyinit_task;
2809 
2810 /*
2811  * This is the function where ext4lazyinit thread lives. It walks
2812  * through the request list searching for next scheduled filesystem.
2813  * When such a fs is found, run the lazy initialization request
2814  * (ext4_rn_li_request) and keep track of the time spend in this
2815  * function. Based on that time we compute next schedule time of
2816  * the request. When walking through the list is complete, compute
2817  * next waking time and put itself into sleep.
2818  */
2819 static int ext4_lazyinit_thread(void *arg)
2820 {
2821 	struct ext4_lazy_init *eli = (struct ext4_lazy_init *)arg;
2822 	struct list_head *pos, *n;
2823 	struct ext4_li_request *elr;
2824 	unsigned long next_wakeup, cur;
2825 
2826 	BUG_ON(NULL == eli);
2827 
2828 cont_thread:
2829 	while (true) {
2830 		next_wakeup = MAX_JIFFY_OFFSET;
2831 
2832 		mutex_lock(&eli->li_list_mtx);
2833 		if (list_empty(&eli->li_request_list)) {
2834 			mutex_unlock(&eli->li_list_mtx);
2835 			goto exit_thread;
2836 		}
2837 
2838 		list_for_each_safe(pos, n, &eli->li_request_list) {
2839 			elr = list_entry(pos, struct ext4_li_request,
2840 					 lr_request);
2841 
2842 			if (time_after_eq(jiffies, elr->lr_next_sched)) {
2843 				if (ext4_run_li_request(elr) != 0) {
2844 					/* error, remove the lazy_init job */
2845 					ext4_remove_li_request(elr);
2846 					continue;
2847 				}
2848 			}
2849 
2850 			if (time_before(elr->lr_next_sched, next_wakeup))
2851 				next_wakeup = elr->lr_next_sched;
2852 		}
2853 		mutex_unlock(&eli->li_list_mtx);
2854 
2855 		try_to_freeze();
2856 
2857 		cur = jiffies;
2858 		if ((time_after_eq(cur, next_wakeup)) ||
2859 		    (MAX_JIFFY_OFFSET == next_wakeup)) {
2860 			cond_resched();
2861 			continue;
2862 		}
2863 
2864 		schedule_timeout_interruptible(next_wakeup - cur);
2865 
2866 		if (kthread_should_stop()) {
2867 			ext4_clear_request_list();
2868 			goto exit_thread;
2869 		}
2870 	}
2871 
2872 exit_thread:
2873 	/*
2874 	 * It looks like the request list is empty, but we need
2875 	 * to check it under the li_list_mtx lock, to prevent any
2876 	 * additions into it, and of course we should lock ext4_li_mtx
2877 	 * to atomically free the list and ext4_li_info, because at
2878 	 * this point another ext4 filesystem could be registering
2879 	 * new one.
2880 	 */
2881 	mutex_lock(&ext4_li_mtx);
2882 	mutex_lock(&eli->li_list_mtx);
2883 	if (!list_empty(&eli->li_request_list)) {
2884 		mutex_unlock(&eli->li_list_mtx);
2885 		mutex_unlock(&ext4_li_mtx);
2886 		goto cont_thread;
2887 	}
2888 	mutex_unlock(&eli->li_list_mtx);
2889 	kfree(ext4_li_info);
2890 	ext4_li_info = NULL;
2891 	mutex_unlock(&ext4_li_mtx);
2892 
2893 	return 0;
2894 }
2895 
2896 static void ext4_clear_request_list(void)
2897 {
2898 	struct list_head *pos, *n;
2899 	struct ext4_li_request *elr;
2900 
2901 	mutex_lock(&ext4_li_info->li_list_mtx);
2902 	list_for_each_safe(pos, n, &ext4_li_info->li_request_list) {
2903 		elr = list_entry(pos, struct ext4_li_request,
2904 				 lr_request);
2905 		ext4_remove_li_request(elr);
2906 	}
2907 	mutex_unlock(&ext4_li_info->li_list_mtx);
2908 }
2909 
2910 static int ext4_run_lazyinit_thread(void)
2911 {
2912 	ext4_lazyinit_task = kthread_run(ext4_lazyinit_thread,
2913 					 ext4_li_info, "ext4lazyinit");
2914 	if (IS_ERR(ext4_lazyinit_task)) {
2915 		int err = PTR_ERR(ext4_lazyinit_task);
2916 		ext4_clear_request_list();
2917 		kfree(ext4_li_info);
2918 		ext4_li_info = NULL;
2919 		printk(KERN_CRIT "EXT4-fs: error %d creating inode table "
2920 				 "initialization thread\n",
2921 				 err);
2922 		return err;
2923 	}
2924 	ext4_li_info->li_state |= EXT4_LAZYINIT_RUNNING;
2925 	return 0;
2926 }
2927 
2928 /*
2929  * Check whether it make sense to run itable init. thread or not.
2930  * If there is at least one uninitialized inode table, return
2931  * corresponding group number, else the loop goes through all
2932  * groups and return total number of groups.
2933  */
2934 static ext4_group_t ext4_has_uninit_itable(struct super_block *sb)
2935 {
2936 	ext4_group_t group, ngroups = EXT4_SB(sb)->s_groups_count;
2937 	struct ext4_group_desc *gdp = NULL;
2938 
2939 	for (group = 0; group < ngroups; group++) {
2940 		gdp = ext4_get_group_desc(sb, group, NULL);
2941 		if (!gdp)
2942 			continue;
2943 
2944 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2945 			break;
2946 	}
2947 
2948 	return group;
2949 }
2950 
2951 static int ext4_li_info_new(void)
2952 {
2953 	struct ext4_lazy_init *eli = NULL;
2954 
2955 	eli = kzalloc(sizeof(*eli), GFP_KERNEL);
2956 	if (!eli)
2957 		return -ENOMEM;
2958 
2959 	INIT_LIST_HEAD(&eli->li_request_list);
2960 	mutex_init(&eli->li_list_mtx);
2961 
2962 	eli->li_state |= EXT4_LAZYINIT_QUIT;
2963 
2964 	ext4_li_info = eli;
2965 
2966 	return 0;
2967 }
2968 
2969 static struct ext4_li_request *ext4_li_request_new(struct super_block *sb,
2970 					    ext4_group_t start)
2971 {
2972 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2973 	struct ext4_li_request *elr;
2974 
2975 	elr = kzalloc(sizeof(*elr), GFP_KERNEL);
2976 	if (!elr)
2977 		return NULL;
2978 
2979 	elr->lr_super = sb;
2980 	elr->lr_sbi = sbi;
2981 	elr->lr_next_group = start;
2982 
2983 	/*
2984 	 * Randomize first schedule time of the request to
2985 	 * spread the inode table initialization requests
2986 	 * better.
2987 	 */
2988 	elr->lr_next_sched = jiffies + (prandom_u32() %
2989 				(EXT4_DEF_LI_MAX_START_DELAY * HZ));
2990 	return elr;
2991 }
2992 
2993 int ext4_register_li_request(struct super_block *sb,
2994 			     ext4_group_t first_not_zeroed)
2995 {
2996 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2997 	struct ext4_li_request *elr = NULL;
2998 	ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
2999 	int ret = 0;
3000 
3001 	mutex_lock(&ext4_li_mtx);
3002 	if (sbi->s_li_request != NULL) {
3003 		/*
3004 		 * Reset timeout so it can be computed again, because
3005 		 * s_li_wait_mult might have changed.
3006 		 */
3007 		sbi->s_li_request->lr_timeout = 0;
3008 		goto out;
3009 	}
3010 
3011 	if (first_not_zeroed == ngroups ||
3012 	    (sb->s_flags & MS_RDONLY) ||
3013 	    !test_opt(sb, INIT_INODE_TABLE))
3014 		goto out;
3015 
3016 	elr = ext4_li_request_new(sb, first_not_zeroed);
3017 	if (!elr) {
3018 		ret = -ENOMEM;
3019 		goto out;
3020 	}
3021 
3022 	if (NULL == ext4_li_info) {
3023 		ret = ext4_li_info_new();
3024 		if (ret)
3025 			goto out;
3026 	}
3027 
3028 	mutex_lock(&ext4_li_info->li_list_mtx);
3029 	list_add(&elr->lr_request, &ext4_li_info->li_request_list);
3030 	mutex_unlock(&ext4_li_info->li_list_mtx);
3031 
3032 	sbi->s_li_request = elr;
3033 	/*
3034 	 * set elr to NULL here since it has been inserted to
3035 	 * the request_list and the removal and free of it is
3036 	 * handled by ext4_clear_request_list from now on.
3037 	 */
3038 	elr = NULL;
3039 
3040 	if (!(ext4_li_info->li_state & EXT4_LAZYINIT_RUNNING)) {
3041 		ret = ext4_run_lazyinit_thread();
3042 		if (ret)
3043 			goto out;
3044 	}
3045 out:
3046 	mutex_unlock(&ext4_li_mtx);
3047 	if (ret)
3048 		kfree(elr);
3049 	return ret;
3050 }
3051 
3052 /*
3053  * We do not need to lock anything since this is called on
3054  * module unload.
3055  */
3056 static void ext4_destroy_lazyinit_thread(void)
3057 {
3058 	/*
3059 	 * If thread exited earlier
3060 	 * there's nothing to be done.
3061 	 */
3062 	if (!ext4_li_info || !ext4_lazyinit_task)
3063 		return;
3064 
3065 	kthread_stop(ext4_lazyinit_task);
3066 }
3067 
3068 static int set_journal_csum_feature_set(struct super_block *sb)
3069 {
3070 	int ret = 1;
3071 	int compat, incompat;
3072 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3073 
3074 	if (ext4_has_metadata_csum(sb)) {
3075 		/* journal checksum v3 */
3076 		compat = 0;
3077 		incompat = JBD2_FEATURE_INCOMPAT_CSUM_V3;
3078 	} else {
3079 		/* journal checksum v1 */
3080 		compat = JBD2_FEATURE_COMPAT_CHECKSUM;
3081 		incompat = 0;
3082 	}
3083 
3084 	jbd2_journal_clear_features(sbi->s_journal,
3085 			JBD2_FEATURE_COMPAT_CHECKSUM, 0,
3086 			JBD2_FEATURE_INCOMPAT_CSUM_V3 |
3087 			JBD2_FEATURE_INCOMPAT_CSUM_V2);
3088 	if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
3089 		ret = jbd2_journal_set_features(sbi->s_journal,
3090 				compat, 0,
3091 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT |
3092 				incompat);
3093 	} else if (test_opt(sb, JOURNAL_CHECKSUM)) {
3094 		ret = jbd2_journal_set_features(sbi->s_journal,
3095 				compat, 0,
3096 				incompat);
3097 		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
3098 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
3099 	} else {
3100 		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
3101 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
3102 	}
3103 
3104 	return ret;
3105 }
3106 
3107 /*
3108  * Note: calculating the overhead so we can be compatible with
3109  * historical BSD practice is quite difficult in the face of
3110  * clusters/bigalloc.  This is because multiple metadata blocks from
3111  * different block group can end up in the same allocation cluster.
3112  * Calculating the exact overhead in the face of clustered allocation
3113  * requires either O(all block bitmaps) in memory or O(number of block
3114  * groups**2) in time.  We will still calculate the superblock for
3115  * older file systems --- and if we come across with a bigalloc file
3116  * system with zero in s_overhead_clusters the estimate will be close to
3117  * correct especially for very large cluster sizes --- but for newer
3118  * file systems, it's better to calculate this figure once at mkfs
3119  * time, and store it in the superblock.  If the superblock value is
3120  * present (even for non-bigalloc file systems), we will use it.
3121  */
3122 static int count_overhead(struct super_block *sb, ext4_group_t grp,
3123 			  char *buf)
3124 {
3125 	struct ext4_sb_info	*sbi = EXT4_SB(sb);
3126 	struct ext4_group_desc	*gdp;
3127 	ext4_fsblk_t		first_block, last_block, b;
3128 	ext4_group_t		i, ngroups = ext4_get_groups_count(sb);
3129 	int			s, j, count = 0;
3130 
3131 	if (!ext4_has_feature_bigalloc(sb))
3132 		return (ext4_bg_has_super(sb, grp) + ext4_bg_num_gdb(sb, grp) +
3133 			sbi->s_itb_per_group + 2);
3134 
3135 	first_block = le32_to_cpu(sbi->s_es->s_first_data_block) +
3136 		(grp * EXT4_BLOCKS_PER_GROUP(sb));
3137 	last_block = first_block + EXT4_BLOCKS_PER_GROUP(sb) - 1;
3138 	for (i = 0; i < ngroups; i++) {
3139 		gdp = ext4_get_group_desc(sb, i, NULL);
3140 		b = ext4_block_bitmap(sb, gdp);
3141 		if (b >= first_block && b <= last_block) {
3142 			ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf);
3143 			count++;
3144 		}
3145 		b = ext4_inode_bitmap(sb, gdp);
3146 		if (b >= first_block && b <= last_block) {
3147 			ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf);
3148 			count++;
3149 		}
3150 		b = ext4_inode_table(sb, gdp);
3151 		if (b >= first_block && b + sbi->s_itb_per_group <= last_block)
3152 			for (j = 0; j < sbi->s_itb_per_group; j++, b++) {
3153 				int c = EXT4_B2C(sbi, b - first_block);
3154 				ext4_set_bit(c, buf);
3155 				count++;
3156 			}
3157 		if (i != grp)
3158 			continue;
3159 		s = 0;
3160 		if (ext4_bg_has_super(sb, grp)) {
3161 			ext4_set_bit(s++, buf);
3162 			count++;
3163 		}
3164 		for (j = ext4_bg_num_gdb(sb, grp); j > 0; j--) {
3165 			ext4_set_bit(EXT4_B2C(sbi, s++), buf);
3166 			count++;
3167 		}
3168 	}
3169 	if (!count)
3170 		return 0;
3171 	return EXT4_CLUSTERS_PER_GROUP(sb) -
3172 		ext4_count_free(buf, EXT4_CLUSTERS_PER_GROUP(sb) / 8);
3173 }
3174 
3175 /*
3176  * Compute the overhead and stash it in sbi->s_overhead
3177  */
3178 int ext4_calculate_overhead(struct super_block *sb)
3179 {
3180 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3181 	struct ext4_super_block *es = sbi->s_es;
3182 	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
3183 	ext4_fsblk_t overhead = 0;
3184 	char *buf = (char *) get_zeroed_page(GFP_NOFS);
3185 
3186 	if (!buf)
3187 		return -ENOMEM;
3188 
3189 	/*
3190 	 * Compute the overhead (FS structures).  This is constant
3191 	 * for a given filesystem unless the number of block groups
3192 	 * changes so we cache the previous value until it does.
3193 	 */
3194 
3195 	/*
3196 	 * All of the blocks before first_data_block are overhead
3197 	 */
3198 	overhead = EXT4_B2C(sbi, le32_to_cpu(es->s_first_data_block));
3199 
3200 	/*
3201 	 * Add the overhead found in each block group
3202 	 */
3203 	for (i = 0; i < ngroups; i++) {
3204 		int blks;
3205 
3206 		blks = count_overhead(sb, i, buf);
3207 		overhead += blks;
3208 		if (blks)
3209 			memset(buf, 0, PAGE_SIZE);
3210 		cond_resched();
3211 	}
3212 	/* Add the internal journal blocks as well */
3213 	if (sbi->s_journal && !sbi->journal_bdev)
3214 		overhead += EXT4_NUM_B2C(sbi, sbi->s_journal->j_maxlen);
3215 
3216 	sbi->s_overhead = overhead;
3217 	smp_wmb();
3218 	free_page((unsigned long) buf);
3219 	return 0;
3220 }
3221 
3222 static void ext4_set_resv_clusters(struct super_block *sb)
3223 {
3224 	ext4_fsblk_t resv_clusters;
3225 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3226 
3227 	/*
3228 	 * There's no need to reserve anything when we aren't using extents.
3229 	 * The space estimates are exact, there are no unwritten extents,
3230 	 * hole punching doesn't need new metadata... This is needed especially
3231 	 * to keep ext2/3 backward compatibility.
3232 	 */
3233 	if (!ext4_has_feature_extents(sb))
3234 		return;
3235 	/*
3236 	 * By default we reserve 2% or 4096 clusters, whichever is smaller.
3237 	 * This should cover the situations where we can not afford to run
3238 	 * out of space like for example punch hole, or converting
3239 	 * unwritten extents in delalloc path. In most cases such
3240 	 * allocation would require 1, or 2 blocks, higher numbers are
3241 	 * very rare.
3242 	 */
3243 	resv_clusters = (ext4_blocks_count(sbi->s_es) >>
3244 			 sbi->s_cluster_bits);
3245 
3246 	do_div(resv_clusters, 50);
3247 	resv_clusters = min_t(ext4_fsblk_t, resv_clusters, 4096);
3248 
3249 	atomic64_set(&sbi->s_resv_clusters, resv_clusters);
3250 }
3251 
3252 static int ext4_fill_super(struct super_block *sb, void *data, int silent)
3253 {
3254 	char *orig_data = kstrdup(data, GFP_KERNEL);
3255 	struct buffer_head *bh;
3256 	struct ext4_super_block *es = NULL;
3257 	struct ext4_sb_info *sbi;
3258 	ext4_fsblk_t block;
3259 	ext4_fsblk_t sb_block = get_sb_block(&data);
3260 	ext4_fsblk_t logical_sb_block;
3261 	unsigned long offset = 0;
3262 	unsigned long journal_devnum = 0;
3263 	unsigned long def_mount_opts;
3264 	struct inode *root;
3265 	const char *descr;
3266 	int ret = -ENOMEM;
3267 	int blocksize, clustersize;
3268 	unsigned int db_count;
3269 	unsigned int i;
3270 	int needs_recovery, has_huge_files, has_bigalloc;
3271 	__u64 blocks_count;
3272 	int err = 0;
3273 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
3274 	ext4_group_t first_not_zeroed;
3275 
3276 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
3277 	if (!sbi)
3278 		goto out_free_orig;
3279 
3280 	sbi->s_blockgroup_lock =
3281 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
3282 	if (!sbi->s_blockgroup_lock) {
3283 		kfree(sbi);
3284 		goto out_free_orig;
3285 	}
3286 	sb->s_fs_info = sbi;
3287 	sbi->s_sb = sb;
3288 	sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
3289 	sbi->s_sb_block = sb_block;
3290 	if (sb->s_bdev->bd_part)
3291 		sbi->s_sectors_written_start =
3292 			part_stat_read(sb->s_bdev->bd_part, sectors[1]);
3293 
3294 	/* Cleanup superblock name */
3295 	strreplace(sb->s_id, '/', '!');
3296 
3297 	/* -EINVAL is default */
3298 	ret = -EINVAL;
3299 	blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
3300 	if (!blocksize) {
3301 		ext4_msg(sb, KERN_ERR, "unable to set blocksize");
3302 		goto out_fail;
3303 	}
3304 
3305 	/*
3306 	 * The ext4 superblock will not be buffer aligned for other than 1kB
3307 	 * block sizes.  We need to calculate the offset from buffer start.
3308 	 */
3309 	if (blocksize != EXT4_MIN_BLOCK_SIZE) {
3310 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3311 		offset = do_div(logical_sb_block, blocksize);
3312 	} else {
3313 		logical_sb_block = sb_block;
3314 	}
3315 
3316 	if (!(bh = sb_bread_unmovable(sb, logical_sb_block))) {
3317 		ext4_msg(sb, KERN_ERR, "unable to read superblock");
3318 		goto out_fail;
3319 	}
3320 	/*
3321 	 * Note: s_es must be initialized as soon as possible because
3322 	 *       some ext4 macro-instructions depend on its value
3323 	 */
3324 	es = (struct ext4_super_block *) (bh->b_data + offset);
3325 	sbi->s_es = es;
3326 	sb->s_magic = le16_to_cpu(es->s_magic);
3327 	if (sb->s_magic != EXT4_SUPER_MAGIC)
3328 		goto cantfind_ext4;
3329 	sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
3330 
3331 	/* Warn if metadata_csum and gdt_csum are both set. */
3332 	if (ext4_has_feature_metadata_csum(sb) &&
3333 	    ext4_has_feature_gdt_csum(sb))
3334 		ext4_warning(sb, "metadata_csum and uninit_bg are "
3335 			     "redundant flags; please run fsck.");
3336 
3337 	/* Check for a known checksum algorithm */
3338 	if (!ext4_verify_csum_type(sb, es)) {
3339 		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
3340 			 "unknown checksum algorithm.");
3341 		silent = 1;
3342 		goto cantfind_ext4;
3343 	}
3344 
3345 	/* Load the checksum driver */
3346 	if (ext4_has_feature_metadata_csum(sb)) {
3347 		sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
3348 		if (IS_ERR(sbi->s_chksum_driver)) {
3349 			ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
3350 			ret = PTR_ERR(sbi->s_chksum_driver);
3351 			sbi->s_chksum_driver = NULL;
3352 			goto failed_mount;
3353 		}
3354 	}
3355 
3356 	/* Check superblock checksum */
3357 	if (!ext4_superblock_csum_verify(sb, es)) {
3358 		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
3359 			 "invalid superblock checksum.  Run e2fsck?");
3360 		silent = 1;
3361 		ret = -EFSBADCRC;
3362 		goto cantfind_ext4;
3363 	}
3364 
3365 	/* Precompute checksum seed for all metadata */
3366 	if (ext4_has_feature_csum_seed(sb))
3367 		sbi->s_csum_seed = le32_to_cpu(es->s_checksum_seed);
3368 	else if (ext4_has_metadata_csum(sb))
3369 		sbi->s_csum_seed = ext4_chksum(sbi, ~0, es->s_uuid,
3370 					       sizeof(es->s_uuid));
3371 
3372 	/* Set defaults before we parse the mount options */
3373 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
3374 	set_opt(sb, INIT_INODE_TABLE);
3375 	if (def_mount_opts & EXT4_DEFM_DEBUG)
3376 		set_opt(sb, DEBUG);
3377 	if (def_mount_opts & EXT4_DEFM_BSDGROUPS)
3378 		set_opt(sb, GRPID);
3379 	if (def_mount_opts & EXT4_DEFM_UID16)
3380 		set_opt(sb, NO_UID32);
3381 	/* xattr user namespace & acls are now defaulted on */
3382 	set_opt(sb, XATTR_USER);
3383 #ifdef CONFIG_EXT4_FS_POSIX_ACL
3384 	set_opt(sb, POSIX_ACL);
3385 #endif
3386 	/* don't forget to enable journal_csum when metadata_csum is enabled. */
3387 	if (ext4_has_metadata_csum(sb))
3388 		set_opt(sb, JOURNAL_CHECKSUM);
3389 
3390 	if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA)
3391 		set_opt(sb, JOURNAL_DATA);
3392 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_ORDERED)
3393 		set_opt(sb, ORDERED_DATA);
3394 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_WBACK)
3395 		set_opt(sb, WRITEBACK_DATA);
3396 
3397 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_PANIC)
3398 		set_opt(sb, ERRORS_PANIC);
3399 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_CONTINUE)
3400 		set_opt(sb, ERRORS_CONT);
3401 	else
3402 		set_opt(sb, ERRORS_RO);
3403 	/* block_validity enabled by default; disable with noblock_validity */
3404 	set_opt(sb, BLOCK_VALIDITY);
3405 	if (def_mount_opts & EXT4_DEFM_DISCARD)
3406 		set_opt(sb, DISCARD);
3407 
3408 	sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
3409 	sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
3410 	sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ;
3411 	sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;
3412 	sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;
3413 
3414 	if ((def_mount_opts & EXT4_DEFM_NOBARRIER) == 0)
3415 		set_opt(sb, BARRIER);
3416 
3417 	/*
3418 	 * enable delayed allocation by default
3419 	 * Use -o nodelalloc to turn it off
3420 	 */
3421 	if (!IS_EXT3_SB(sb) && !IS_EXT2_SB(sb) &&
3422 	    ((def_mount_opts & EXT4_DEFM_NODELALLOC) == 0))
3423 		set_opt(sb, DELALLOC);
3424 
3425 	/*
3426 	 * set default s_li_wait_mult for lazyinit, for the case there is
3427 	 * no mount option specified.
3428 	 */
3429 	sbi->s_li_wait_mult = EXT4_DEF_LI_WAIT_MULT;
3430 
3431 	if (!parse_options((char *) sbi->s_es->s_mount_opts, sb,
3432 			   &journal_devnum, &journal_ioprio, 0)) {
3433 		ext4_msg(sb, KERN_WARNING,
3434 			 "failed to parse options in superblock: %s",
3435 			 sbi->s_es->s_mount_opts);
3436 	}
3437 	sbi->s_def_mount_opt = sbi->s_mount_opt;
3438 	if (!parse_options((char *) data, sb, &journal_devnum,
3439 			   &journal_ioprio, 0))
3440 		goto failed_mount;
3441 
3442 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
3443 		printk_once(KERN_WARNING "EXT4-fs: Warning: mounting "
3444 			    "with data=journal disables delayed "
3445 			    "allocation and O_DIRECT support!\n");
3446 		if (test_opt2(sb, EXPLICIT_DELALLOC)) {
3447 			ext4_msg(sb, KERN_ERR, "can't mount with "
3448 				 "both data=journal and delalloc");
3449 			goto failed_mount;
3450 		}
3451 		if (test_opt(sb, DIOREAD_NOLOCK)) {
3452 			ext4_msg(sb, KERN_ERR, "can't mount with "
3453 				 "both data=journal and dioread_nolock");
3454 			goto failed_mount;
3455 		}
3456 		if (test_opt(sb, DAX)) {
3457 			ext4_msg(sb, KERN_ERR, "can't mount with "
3458 				 "both data=journal and dax");
3459 			goto failed_mount;
3460 		}
3461 		if (test_opt(sb, DELALLOC))
3462 			clear_opt(sb, DELALLOC);
3463 	} else {
3464 		sb->s_iflags |= SB_I_CGROUPWB;
3465 	}
3466 
3467 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
3468 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
3469 
3470 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
3471 	    (ext4_has_compat_features(sb) ||
3472 	     ext4_has_ro_compat_features(sb) ||
3473 	     ext4_has_incompat_features(sb)))
3474 		ext4_msg(sb, KERN_WARNING,
3475 		       "feature flags set on rev 0 fs, "
3476 		       "running e2fsck is recommended");
3477 
3478 	if (es->s_creator_os == cpu_to_le32(EXT4_OS_HURD)) {
3479 		set_opt2(sb, HURD_COMPAT);
3480 		if (ext4_has_feature_64bit(sb)) {
3481 			ext4_msg(sb, KERN_ERR,
3482 				 "The Hurd can't support 64-bit file systems");
3483 			goto failed_mount;
3484 		}
3485 	}
3486 
3487 	if (IS_EXT2_SB(sb)) {
3488 		if (ext2_feature_set_ok(sb))
3489 			ext4_msg(sb, KERN_INFO, "mounting ext2 file system "
3490 				 "using the ext4 subsystem");
3491 		else {
3492 			ext4_msg(sb, KERN_ERR, "couldn't mount as ext2 due "
3493 				 "to feature incompatibilities");
3494 			goto failed_mount;
3495 		}
3496 	}
3497 
3498 	if (IS_EXT3_SB(sb)) {
3499 		if (ext3_feature_set_ok(sb))
3500 			ext4_msg(sb, KERN_INFO, "mounting ext3 file system "
3501 				 "using the ext4 subsystem");
3502 		else {
3503 			ext4_msg(sb, KERN_ERR, "couldn't mount as ext3 due "
3504 				 "to feature incompatibilities");
3505 			goto failed_mount;
3506 		}
3507 	}
3508 
3509 	/*
3510 	 * Check feature flags regardless of the revision level, since we
3511 	 * previously didn't change the revision level when setting the flags,
3512 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
3513 	 */
3514 	if (!ext4_feature_set_ok(sb, (sb->s_flags & MS_RDONLY)))
3515 		goto failed_mount;
3516 
3517 	blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
3518 	if (blocksize < EXT4_MIN_BLOCK_SIZE ||
3519 	    blocksize > EXT4_MAX_BLOCK_SIZE) {
3520 		ext4_msg(sb, KERN_ERR,
3521 		       "Unsupported filesystem blocksize %d", blocksize);
3522 		goto failed_mount;
3523 	}
3524 
3525 	if (le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) > (blocksize / 4)) {
3526 		ext4_msg(sb, KERN_ERR,
3527 			 "Number of reserved GDT blocks insanely large: %d",
3528 			 le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks));
3529 		goto failed_mount;
3530 	}
3531 
3532 	if (sbi->s_mount_opt & EXT4_MOUNT_DAX) {
3533 		err = bdev_dax_supported(sb, blocksize);
3534 		if (err)
3535 			goto failed_mount;
3536 	}
3537 
3538 	if (ext4_has_feature_encrypt(sb) && es->s_encryption_level) {
3539 		ext4_msg(sb, KERN_ERR, "Unsupported encryption level %d",
3540 			 es->s_encryption_level);
3541 		goto failed_mount;
3542 	}
3543 
3544 	if (sb->s_blocksize != blocksize) {
3545 		/* Validate the filesystem blocksize */
3546 		if (!sb_set_blocksize(sb, blocksize)) {
3547 			ext4_msg(sb, KERN_ERR, "bad block size %d",
3548 					blocksize);
3549 			goto failed_mount;
3550 		}
3551 
3552 		brelse(bh);
3553 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3554 		offset = do_div(logical_sb_block, blocksize);
3555 		bh = sb_bread_unmovable(sb, logical_sb_block);
3556 		if (!bh) {
3557 			ext4_msg(sb, KERN_ERR,
3558 			       "Can't read superblock on 2nd try");
3559 			goto failed_mount;
3560 		}
3561 		es = (struct ext4_super_block *)(bh->b_data + offset);
3562 		sbi->s_es = es;
3563 		if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
3564 			ext4_msg(sb, KERN_ERR,
3565 			       "Magic mismatch, very weird!");
3566 			goto failed_mount;
3567 		}
3568 	}
3569 
3570 	has_huge_files = ext4_has_feature_huge_file(sb);
3571 	sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits,
3572 						      has_huge_files);
3573 	sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits, has_huge_files);
3574 
3575 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) {
3576 		sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE;
3577 		sbi->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
3578 	} else {
3579 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
3580 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
3581 		if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
3582 		    (!is_power_of_2(sbi->s_inode_size)) ||
3583 		    (sbi->s_inode_size > blocksize)) {
3584 			ext4_msg(sb, KERN_ERR,
3585 			       "unsupported inode size: %d",
3586 			       sbi->s_inode_size);
3587 			goto failed_mount;
3588 		}
3589 		if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE)
3590 			sb->s_time_gran = 1 << (EXT4_EPOCH_BITS - 2);
3591 	}
3592 
3593 	sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
3594 	if (ext4_has_feature_64bit(sb)) {
3595 		if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT ||
3596 		    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
3597 		    !is_power_of_2(sbi->s_desc_size)) {
3598 			ext4_msg(sb, KERN_ERR,
3599 			       "unsupported descriptor size %lu",
3600 			       sbi->s_desc_size);
3601 			goto failed_mount;
3602 		}
3603 	} else
3604 		sbi->s_desc_size = EXT4_MIN_DESC_SIZE;
3605 
3606 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
3607 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
3608 	if (EXT4_INODE_SIZE(sb) == 0 || EXT4_INODES_PER_GROUP(sb) == 0)
3609 		goto cantfind_ext4;
3610 
3611 	sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
3612 	if (sbi->s_inodes_per_block == 0)
3613 		goto cantfind_ext4;
3614 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
3615 					sbi->s_inodes_per_block;
3616 	sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
3617 	sbi->s_sbh = bh;
3618 	sbi->s_mount_state = le16_to_cpu(es->s_state);
3619 	sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
3620 	sbi->s_desc_per_block_bits = ilog2(EXT4_DESC_PER_BLOCK(sb));
3621 
3622 	for (i = 0; i < 4; i++)
3623 		sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
3624 	sbi->s_def_hash_version = es->s_def_hash_version;
3625 	if (ext4_has_feature_dir_index(sb)) {
3626 		i = le32_to_cpu(es->s_flags);
3627 		if (i & EXT2_FLAGS_UNSIGNED_HASH)
3628 			sbi->s_hash_unsigned = 3;
3629 		else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) {
3630 #ifdef __CHAR_UNSIGNED__
3631 			if (!(sb->s_flags & MS_RDONLY))
3632 				es->s_flags |=
3633 					cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH);
3634 			sbi->s_hash_unsigned = 3;
3635 #else
3636 			if (!(sb->s_flags & MS_RDONLY))
3637 				es->s_flags |=
3638 					cpu_to_le32(EXT2_FLAGS_SIGNED_HASH);
3639 #endif
3640 		}
3641 	}
3642 
3643 	/* Handle clustersize */
3644 	clustersize = BLOCK_SIZE << le32_to_cpu(es->s_log_cluster_size);
3645 	has_bigalloc = ext4_has_feature_bigalloc(sb);
3646 	if (has_bigalloc) {
3647 		if (clustersize < blocksize) {
3648 			ext4_msg(sb, KERN_ERR,
3649 				 "cluster size (%d) smaller than "
3650 				 "block size (%d)", clustersize, blocksize);
3651 			goto failed_mount;
3652 		}
3653 		sbi->s_cluster_bits = le32_to_cpu(es->s_log_cluster_size) -
3654 			le32_to_cpu(es->s_log_block_size);
3655 		sbi->s_clusters_per_group =
3656 			le32_to_cpu(es->s_clusters_per_group);
3657 		if (sbi->s_clusters_per_group > blocksize * 8) {
3658 			ext4_msg(sb, KERN_ERR,
3659 				 "#clusters per group too big: %lu",
3660 				 sbi->s_clusters_per_group);
3661 			goto failed_mount;
3662 		}
3663 		if (sbi->s_blocks_per_group !=
3664 		    (sbi->s_clusters_per_group * (clustersize / blocksize))) {
3665 			ext4_msg(sb, KERN_ERR, "blocks per group (%lu) and "
3666 				 "clusters per group (%lu) inconsistent",
3667 				 sbi->s_blocks_per_group,
3668 				 sbi->s_clusters_per_group);
3669 			goto failed_mount;
3670 		}
3671 	} else {
3672 		if (clustersize != blocksize) {
3673 			ext4_warning(sb, "fragment/cluster size (%d) != "
3674 				     "block size (%d)", clustersize,
3675 				     blocksize);
3676 			clustersize = blocksize;
3677 		}
3678 		if (sbi->s_blocks_per_group > blocksize * 8) {
3679 			ext4_msg(sb, KERN_ERR,
3680 				 "#blocks per group too big: %lu",
3681 				 sbi->s_blocks_per_group);
3682 			goto failed_mount;
3683 		}
3684 		sbi->s_clusters_per_group = sbi->s_blocks_per_group;
3685 		sbi->s_cluster_bits = 0;
3686 	}
3687 	sbi->s_cluster_ratio = clustersize / blocksize;
3688 
3689 	if (sbi->s_inodes_per_group > blocksize * 8) {
3690 		ext4_msg(sb, KERN_ERR,
3691 		       "#inodes per group too big: %lu",
3692 		       sbi->s_inodes_per_group);
3693 		goto failed_mount;
3694 	}
3695 
3696 	/* Do we have standard group size of clustersize * 8 blocks ? */
3697 	if (sbi->s_blocks_per_group == clustersize << 3)
3698 		set_opt2(sb, STD_GROUP_SIZE);
3699 
3700 	/*
3701 	 * Test whether we have more sectors than will fit in sector_t,
3702 	 * and whether the max offset is addressable by the page cache.
3703 	 */
3704 	err = generic_check_addressable(sb->s_blocksize_bits,
3705 					ext4_blocks_count(es));
3706 	if (err) {
3707 		ext4_msg(sb, KERN_ERR, "filesystem"
3708 			 " too large to mount safely on this system");
3709 		if (sizeof(sector_t) < 8)
3710 			ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled");
3711 		goto failed_mount;
3712 	}
3713 
3714 	if (EXT4_BLOCKS_PER_GROUP(sb) == 0)
3715 		goto cantfind_ext4;
3716 
3717 	/* check blocks count against device size */
3718 	blocks_count = sb->s_bdev->bd_inode->i_size >> sb->s_blocksize_bits;
3719 	if (blocks_count && ext4_blocks_count(es) > blocks_count) {
3720 		ext4_msg(sb, KERN_WARNING, "bad geometry: block count %llu "
3721 		       "exceeds size of device (%llu blocks)",
3722 		       ext4_blocks_count(es), blocks_count);
3723 		goto failed_mount;
3724 	}
3725 
3726 	/*
3727 	 * It makes no sense for the first data block to be beyond the end
3728 	 * of the filesystem.
3729 	 */
3730 	if (le32_to_cpu(es->s_first_data_block) >= ext4_blocks_count(es)) {
3731 		ext4_msg(sb, KERN_WARNING, "bad geometry: first data "
3732 			 "block %u is beyond end of filesystem (%llu)",
3733 			 le32_to_cpu(es->s_first_data_block),
3734 			 ext4_blocks_count(es));
3735 		goto failed_mount;
3736 	}
3737 	blocks_count = (ext4_blocks_count(es) -
3738 			le32_to_cpu(es->s_first_data_block) +
3739 			EXT4_BLOCKS_PER_GROUP(sb) - 1);
3740 	do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
3741 	if (blocks_count > ((uint64_t)1<<32) - EXT4_DESC_PER_BLOCK(sb)) {
3742 		ext4_msg(sb, KERN_WARNING, "groups count too large: %u "
3743 		       "(block count %llu, first data block %u, "
3744 		       "blocks per group %lu)", sbi->s_groups_count,
3745 		       ext4_blocks_count(es),
3746 		       le32_to_cpu(es->s_first_data_block),
3747 		       EXT4_BLOCKS_PER_GROUP(sb));
3748 		goto failed_mount;
3749 	}
3750 	sbi->s_groups_count = blocks_count;
3751 	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
3752 			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
3753 	db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
3754 		   EXT4_DESC_PER_BLOCK(sb);
3755 	sbi->s_group_desc = ext4_kvmalloc(db_count *
3756 					  sizeof(struct buffer_head *),
3757 					  GFP_KERNEL);
3758 	if (sbi->s_group_desc == NULL) {
3759 		ext4_msg(sb, KERN_ERR, "not enough memory");
3760 		ret = -ENOMEM;
3761 		goto failed_mount;
3762 	}
3763 
3764 	bgl_lock_init(sbi->s_blockgroup_lock);
3765 
3766 	for (i = 0; i < db_count; i++) {
3767 		block = descriptor_loc(sb, logical_sb_block, i);
3768 		sbi->s_group_desc[i] = sb_bread_unmovable(sb, block);
3769 		if (!sbi->s_group_desc[i]) {
3770 			ext4_msg(sb, KERN_ERR,
3771 			       "can't read group descriptor %d", i);
3772 			db_count = i;
3773 			goto failed_mount2;
3774 		}
3775 	}
3776 	if (!ext4_check_descriptors(sb, logical_sb_block, &first_not_zeroed)) {
3777 		ext4_msg(sb, KERN_ERR, "group descriptors corrupted!");
3778 		ret = -EFSCORRUPTED;
3779 		goto failed_mount2;
3780 	}
3781 
3782 	sbi->s_gdb_count = db_count;
3783 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
3784 	spin_lock_init(&sbi->s_next_gen_lock);
3785 
3786 	setup_timer(&sbi->s_err_report, print_daily_error_info,
3787 		(unsigned long) sb);
3788 
3789 	/* Register extent status tree shrinker */
3790 	if (ext4_es_register_shrinker(sbi))
3791 		goto failed_mount3;
3792 
3793 	sbi->s_stripe = ext4_get_stripe_size(sbi);
3794 	sbi->s_extent_max_zeroout_kb = 32;
3795 
3796 	/*
3797 	 * set up enough so that it can read an inode
3798 	 */
3799 	sb->s_op = &ext4_sops;
3800 	sb->s_export_op = &ext4_export_ops;
3801 	sb->s_xattr = ext4_xattr_handlers;
3802 	sb->s_cop = &ext4_cryptops;
3803 #ifdef CONFIG_QUOTA
3804 	sb->dq_op = &ext4_quota_operations;
3805 	if (ext4_has_feature_quota(sb))
3806 		sb->s_qcop = &dquot_quotactl_sysfile_ops;
3807 	else
3808 		sb->s_qcop = &ext4_qctl_operations;
3809 	sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP | QTYPE_MASK_PRJ;
3810 #endif
3811 	memcpy(sb->s_uuid, es->s_uuid, sizeof(es->s_uuid));
3812 
3813 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
3814 	mutex_init(&sbi->s_orphan_lock);
3815 
3816 	sb->s_root = NULL;
3817 
3818 	needs_recovery = (es->s_last_orphan != 0 ||
3819 			  ext4_has_feature_journal_needs_recovery(sb));
3820 
3821 	if (ext4_has_feature_mmp(sb) && !(sb->s_flags & MS_RDONLY))
3822 		if (ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block)))
3823 			goto failed_mount3a;
3824 
3825 	/*
3826 	 * The first inode we look at is the journal inode.  Don't try
3827 	 * root first: it may be modified in the journal!
3828 	 */
3829 	if (!test_opt(sb, NOLOAD) && ext4_has_feature_journal(sb)) {
3830 		if (ext4_load_journal(sb, es, journal_devnum))
3831 			goto failed_mount3a;
3832 	} else if (test_opt(sb, NOLOAD) && !(sb->s_flags & MS_RDONLY) &&
3833 		   ext4_has_feature_journal_needs_recovery(sb)) {
3834 		ext4_msg(sb, KERN_ERR, "required journal recovery "
3835 		       "suppressed and not mounted read-only");
3836 		goto failed_mount_wq;
3837 	} else {
3838 		/* Nojournal mode, all journal mount options are illegal */
3839 		if (test_opt2(sb, EXPLICIT_JOURNAL_CHECKSUM)) {
3840 			ext4_msg(sb, KERN_ERR, "can't mount with "
3841 				 "journal_checksum, fs mounted w/o journal");
3842 			goto failed_mount_wq;
3843 		}
3844 		if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
3845 			ext4_msg(sb, KERN_ERR, "can't mount with "
3846 				 "journal_async_commit, fs mounted w/o journal");
3847 			goto failed_mount_wq;
3848 		}
3849 		if (sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ) {
3850 			ext4_msg(sb, KERN_ERR, "can't mount with "
3851 				 "commit=%lu, fs mounted w/o journal",
3852 				 sbi->s_commit_interval / HZ);
3853 			goto failed_mount_wq;
3854 		}
3855 		if (EXT4_MOUNT_DATA_FLAGS &
3856 		    (sbi->s_mount_opt ^ sbi->s_def_mount_opt)) {
3857 			ext4_msg(sb, KERN_ERR, "can't mount with "
3858 				 "data=, fs mounted w/o journal");
3859 			goto failed_mount_wq;
3860 		}
3861 		sbi->s_def_mount_opt &= EXT4_MOUNT_JOURNAL_CHECKSUM;
3862 		clear_opt(sb, JOURNAL_CHECKSUM);
3863 		clear_opt(sb, DATA_FLAGS);
3864 		sbi->s_journal = NULL;
3865 		needs_recovery = 0;
3866 		goto no_journal;
3867 	}
3868 
3869 	if (ext4_has_feature_64bit(sb) &&
3870 	    !jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
3871 				       JBD2_FEATURE_INCOMPAT_64BIT)) {
3872 		ext4_msg(sb, KERN_ERR, "Failed to set 64-bit journal feature");
3873 		goto failed_mount_wq;
3874 	}
3875 
3876 	if (!set_journal_csum_feature_set(sb)) {
3877 		ext4_msg(sb, KERN_ERR, "Failed to set journal checksum "
3878 			 "feature set");
3879 		goto failed_mount_wq;
3880 	}
3881 
3882 	/* We have now updated the journal if required, so we can
3883 	 * validate the data journaling mode. */
3884 	switch (test_opt(sb, DATA_FLAGS)) {
3885 	case 0:
3886 		/* No mode set, assume a default based on the journal
3887 		 * capabilities: ORDERED_DATA if the journal can
3888 		 * cope, else JOURNAL_DATA
3889 		 */
3890 		if (jbd2_journal_check_available_features
3891 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE))
3892 			set_opt(sb, ORDERED_DATA);
3893 		else
3894 			set_opt(sb, JOURNAL_DATA);
3895 		break;
3896 
3897 	case EXT4_MOUNT_ORDERED_DATA:
3898 	case EXT4_MOUNT_WRITEBACK_DATA:
3899 		if (!jbd2_journal_check_available_features
3900 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
3901 			ext4_msg(sb, KERN_ERR, "Journal does not support "
3902 			       "requested data journaling mode");
3903 			goto failed_mount_wq;
3904 		}
3905 	default:
3906 		break;
3907 	}
3908 	set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
3909 
3910 	sbi->s_journal->j_commit_callback = ext4_journal_commit_callback;
3911 
3912 no_journal:
3913 	sbi->s_mb_cache = ext4_xattr_create_cache();
3914 	if (!sbi->s_mb_cache) {
3915 		ext4_msg(sb, KERN_ERR, "Failed to create an mb_cache");
3916 		goto failed_mount_wq;
3917 	}
3918 
3919 	if ((DUMMY_ENCRYPTION_ENABLED(sbi) || ext4_has_feature_encrypt(sb)) &&
3920 	    (blocksize != PAGE_SIZE)) {
3921 		ext4_msg(sb, KERN_ERR,
3922 			 "Unsupported blocksize for fs encryption");
3923 		goto failed_mount_wq;
3924 	}
3925 
3926 	if (DUMMY_ENCRYPTION_ENABLED(sbi) && !(sb->s_flags & MS_RDONLY) &&
3927 	    !ext4_has_feature_encrypt(sb)) {
3928 		ext4_set_feature_encrypt(sb);
3929 		ext4_commit_super(sb, 1);
3930 	}
3931 
3932 	/*
3933 	 * Get the # of file system overhead blocks from the
3934 	 * superblock if present.
3935 	 */
3936 	if (es->s_overhead_clusters)
3937 		sbi->s_overhead = le32_to_cpu(es->s_overhead_clusters);
3938 	else {
3939 		err = ext4_calculate_overhead(sb);
3940 		if (err)
3941 			goto failed_mount_wq;
3942 	}
3943 
3944 	/*
3945 	 * The maximum number of concurrent works can be high and
3946 	 * concurrency isn't really necessary.  Limit it to 1.
3947 	 */
3948 	EXT4_SB(sb)->rsv_conversion_wq =
3949 		alloc_workqueue("ext4-rsv-conversion", WQ_MEM_RECLAIM | WQ_UNBOUND, 1);
3950 	if (!EXT4_SB(sb)->rsv_conversion_wq) {
3951 		printk(KERN_ERR "EXT4-fs: failed to create workqueue\n");
3952 		ret = -ENOMEM;
3953 		goto failed_mount4;
3954 	}
3955 
3956 	/*
3957 	 * The jbd2_journal_load will have done any necessary log recovery,
3958 	 * so we can safely mount the rest of the filesystem now.
3959 	 */
3960 
3961 	root = ext4_iget(sb, EXT4_ROOT_INO);
3962 	if (IS_ERR(root)) {
3963 		ext4_msg(sb, KERN_ERR, "get root inode failed");
3964 		ret = PTR_ERR(root);
3965 		root = NULL;
3966 		goto failed_mount4;
3967 	}
3968 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
3969 		ext4_msg(sb, KERN_ERR, "corrupt root inode, run e2fsck");
3970 		iput(root);
3971 		goto failed_mount4;
3972 	}
3973 	sb->s_root = d_make_root(root);
3974 	if (!sb->s_root) {
3975 		ext4_msg(sb, KERN_ERR, "get root dentry failed");
3976 		ret = -ENOMEM;
3977 		goto failed_mount4;
3978 	}
3979 
3980 	if (ext4_setup_super(sb, es, sb->s_flags & MS_RDONLY))
3981 		sb->s_flags |= MS_RDONLY;
3982 
3983 	/* determine the minimum size of new large inodes, if present */
3984 	if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
3985 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
3986 						     EXT4_GOOD_OLD_INODE_SIZE;
3987 		if (ext4_has_feature_extra_isize(sb)) {
3988 			if (sbi->s_want_extra_isize <
3989 			    le16_to_cpu(es->s_want_extra_isize))
3990 				sbi->s_want_extra_isize =
3991 					le16_to_cpu(es->s_want_extra_isize);
3992 			if (sbi->s_want_extra_isize <
3993 			    le16_to_cpu(es->s_min_extra_isize))
3994 				sbi->s_want_extra_isize =
3995 					le16_to_cpu(es->s_min_extra_isize);
3996 		}
3997 	}
3998 	/* Check if enough inode space is available */
3999 	if (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize >
4000 							sbi->s_inode_size) {
4001 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
4002 						       EXT4_GOOD_OLD_INODE_SIZE;
4003 		ext4_msg(sb, KERN_INFO, "required extra inode space not"
4004 			 "available");
4005 	}
4006 
4007 	ext4_set_resv_clusters(sb);
4008 
4009 	err = ext4_setup_system_zone(sb);
4010 	if (err) {
4011 		ext4_msg(sb, KERN_ERR, "failed to initialize system "
4012 			 "zone (%d)", err);
4013 		goto failed_mount4a;
4014 	}
4015 
4016 	ext4_ext_init(sb);
4017 	err = ext4_mb_init(sb);
4018 	if (err) {
4019 		ext4_msg(sb, KERN_ERR, "failed to initialize mballoc (%d)",
4020 			 err);
4021 		goto failed_mount5;
4022 	}
4023 
4024 	block = ext4_count_free_clusters(sb);
4025 	ext4_free_blocks_count_set(sbi->s_es,
4026 				   EXT4_C2B(sbi, block));
4027 	err = percpu_counter_init(&sbi->s_freeclusters_counter, block,
4028 				  GFP_KERNEL);
4029 	if (!err) {
4030 		unsigned long freei = ext4_count_free_inodes(sb);
4031 		sbi->s_es->s_free_inodes_count = cpu_to_le32(freei);
4032 		err = percpu_counter_init(&sbi->s_freeinodes_counter, freei,
4033 					  GFP_KERNEL);
4034 	}
4035 	if (!err)
4036 		err = percpu_counter_init(&sbi->s_dirs_counter,
4037 					  ext4_count_dirs(sb), GFP_KERNEL);
4038 	if (!err)
4039 		err = percpu_counter_init(&sbi->s_dirtyclusters_counter, 0,
4040 					  GFP_KERNEL);
4041 	if (!err)
4042 		err = percpu_init_rwsem(&sbi->s_journal_flag_rwsem);
4043 
4044 	if (err) {
4045 		ext4_msg(sb, KERN_ERR, "insufficient memory");
4046 		goto failed_mount6;
4047 	}
4048 
4049 	if (ext4_has_feature_flex_bg(sb))
4050 		if (!ext4_fill_flex_info(sb)) {
4051 			ext4_msg(sb, KERN_ERR,
4052 			       "unable to initialize "
4053 			       "flex_bg meta info!");
4054 			goto failed_mount6;
4055 		}
4056 
4057 	err = ext4_register_li_request(sb, first_not_zeroed);
4058 	if (err)
4059 		goto failed_mount6;
4060 
4061 	err = ext4_register_sysfs(sb);
4062 	if (err)
4063 		goto failed_mount7;
4064 
4065 #ifdef CONFIG_QUOTA
4066 	/* Enable quota usage during mount. */
4067 	if (ext4_has_feature_quota(sb) && !(sb->s_flags & MS_RDONLY)) {
4068 		err = ext4_enable_quotas(sb);
4069 		if (err)
4070 			goto failed_mount8;
4071 	}
4072 #endif  /* CONFIG_QUOTA */
4073 
4074 	EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
4075 	ext4_orphan_cleanup(sb, es);
4076 	EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
4077 	if (needs_recovery) {
4078 		ext4_msg(sb, KERN_INFO, "recovery complete");
4079 		ext4_mark_recovery_complete(sb, es);
4080 	}
4081 	if (EXT4_SB(sb)->s_journal) {
4082 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
4083 			descr = " journalled data mode";
4084 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
4085 			descr = " ordered data mode";
4086 		else
4087 			descr = " writeback data mode";
4088 	} else
4089 		descr = "out journal";
4090 
4091 	if (test_opt(sb, DISCARD)) {
4092 		struct request_queue *q = bdev_get_queue(sb->s_bdev);
4093 		if (!blk_queue_discard(q))
4094 			ext4_msg(sb, KERN_WARNING,
4095 				 "mounting with \"discard\" option, but "
4096 				 "the device does not support discard");
4097 	}
4098 
4099 	if (___ratelimit(&ext4_mount_msg_ratelimit, "EXT4-fs mount"))
4100 		ext4_msg(sb, KERN_INFO, "mounted filesystem with%s. "
4101 			 "Opts: %s%s%s", descr, sbi->s_es->s_mount_opts,
4102 			 *sbi->s_es->s_mount_opts ? "; " : "", orig_data);
4103 
4104 	if (es->s_error_count)
4105 		mod_timer(&sbi->s_err_report, jiffies + 300*HZ); /* 5 minutes */
4106 
4107 	/* Enable message ratelimiting. Default is 10 messages per 5 secs. */
4108 	ratelimit_state_init(&sbi->s_err_ratelimit_state, 5 * HZ, 10);
4109 	ratelimit_state_init(&sbi->s_warning_ratelimit_state, 5 * HZ, 10);
4110 	ratelimit_state_init(&sbi->s_msg_ratelimit_state, 5 * HZ, 10);
4111 
4112 	kfree(orig_data);
4113 #ifdef CONFIG_EXT4_FS_ENCRYPTION
4114 	memcpy(sbi->key_prefix, EXT4_KEY_DESC_PREFIX,
4115 				EXT4_KEY_DESC_PREFIX_SIZE);
4116 	sbi->key_prefix_size = EXT4_KEY_DESC_PREFIX_SIZE;
4117 #endif
4118 	return 0;
4119 
4120 cantfind_ext4:
4121 	if (!silent)
4122 		ext4_msg(sb, KERN_ERR, "VFS: Can't find ext4 filesystem");
4123 	goto failed_mount;
4124 
4125 #ifdef CONFIG_QUOTA
4126 failed_mount8:
4127 	ext4_unregister_sysfs(sb);
4128 #endif
4129 failed_mount7:
4130 	ext4_unregister_li_request(sb);
4131 failed_mount6:
4132 	ext4_mb_release(sb);
4133 	if (sbi->s_flex_groups)
4134 		kvfree(sbi->s_flex_groups);
4135 	percpu_counter_destroy(&sbi->s_freeclusters_counter);
4136 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
4137 	percpu_counter_destroy(&sbi->s_dirs_counter);
4138 	percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
4139 failed_mount5:
4140 	ext4_ext_release(sb);
4141 	ext4_release_system_zone(sb);
4142 failed_mount4a:
4143 	dput(sb->s_root);
4144 	sb->s_root = NULL;
4145 failed_mount4:
4146 	ext4_msg(sb, KERN_ERR, "mount failed");
4147 	if (EXT4_SB(sb)->rsv_conversion_wq)
4148 		destroy_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
4149 failed_mount_wq:
4150 	if (sbi->s_mb_cache) {
4151 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
4152 		sbi->s_mb_cache = NULL;
4153 	}
4154 	if (sbi->s_journal) {
4155 		jbd2_journal_destroy(sbi->s_journal);
4156 		sbi->s_journal = NULL;
4157 	}
4158 failed_mount3a:
4159 	ext4_es_unregister_shrinker(sbi);
4160 failed_mount3:
4161 	del_timer_sync(&sbi->s_err_report);
4162 	if (sbi->s_mmp_tsk)
4163 		kthread_stop(sbi->s_mmp_tsk);
4164 failed_mount2:
4165 	for (i = 0; i < db_count; i++)
4166 		brelse(sbi->s_group_desc[i]);
4167 	kvfree(sbi->s_group_desc);
4168 failed_mount:
4169 	if (sbi->s_chksum_driver)
4170 		crypto_free_shash(sbi->s_chksum_driver);
4171 #ifdef CONFIG_QUOTA
4172 	for (i = 0; i < EXT4_MAXQUOTAS; i++)
4173 		kfree(sbi->s_qf_names[i]);
4174 #endif
4175 	ext4_blkdev_remove(sbi);
4176 	brelse(bh);
4177 out_fail:
4178 	sb->s_fs_info = NULL;
4179 	kfree(sbi->s_blockgroup_lock);
4180 	kfree(sbi);
4181 out_free_orig:
4182 	kfree(orig_data);
4183 	return err ? err : ret;
4184 }
4185 
4186 /*
4187  * Setup any per-fs journal parameters now.  We'll do this both on
4188  * initial mount, once the journal has been initialised but before we've
4189  * done any recovery; and again on any subsequent remount.
4190  */
4191 static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
4192 {
4193 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4194 
4195 	journal->j_commit_interval = sbi->s_commit_interval;
4196 	journal->j_min_batch_time = sbi->s_min_batch_time;
4197 	journal->j_max_batch_time = sbi->s_max_batch_time;
4198 
4199 	write_lock(&journal->j_state_lock);
4200 	if (test_opt(sb, BARRIER))
4201 		journal->j_flags |= JBD2_BARRIER;
4202 	else
4203 		journal->j_flags &= ~JBD2_BARRIER;
4204 	if (test_opt(sb, DATA_ERR_ABORT))
4205 		journal->j_flags |= JBD2_ABORT_ON_SYNCDATA_ERR;
4206 	else
4207 		journal->j_flags &= ~JBD2_ABORT_ON_SYNCDATA_ERR;
4208 	write_unlock(&journal->j_state_lock);
4209 }
4210 
4211 static journal_t *ext4_get_journal(struct super_block *sb,
4212 				   unsigned int journal_inum)
4213 {
4214 	struct inode *journal_inode;
4215 	journal_t *journal;
4216 
4217 	BUG_ON(!ext4_has_feature_journal(sb));
4218 
4219 	/* First, test for the existence of a valid inode on disk.  Bad
4220 	 * things happen if we iget() an unused inode, as the subsequent
4221 	 * iput() will try to delete it. */
4222 
4223 	journal_inode = ext4_iget(sb, journal_inum);
4224 	if (IS_ERR(journal_inode)) {
4225 		ext4_msg(sb, KERN_ERR, "no journal found");
4226 		return NULL;
4227 	}
4228 	if (!journal_inode->i_nlink) {
4229 		make_bad_inode(journal_inode);
4230 		iput(journal_inode);
4231 		ext4_msg(sb, KERN_ERR, "journal inode is deleted");
4232 		return NULL;
4233 	}
4234 
4235 	jbd_debug(2, "Journal inode found at %p: %lld bytes\n",
4236 		  journal_inode, journal_inode->i_size);
4237 	if (!S_ISREG(journal_inode->i_mode)) {
4238 		ext4_msg(sb, KERN_ERR, "invalid journal inode");
4239 		iput(journal_inode);
4240 		return NULL;
4241 	}
4242 
4243 	journal = jbd2_journal_init_inode(journal_inode);
4244 	if (!journal) {
4245 		ext4_msg(sb, KERN_ERR, "Could not load journal inode");
4246 		iput(journal_inode);
4247 		return NULL;
4248 	}
4249 	journal->j_private = sb;
4250 	ext4_init_journal_params(sb, journal);
4251 	return journal;
4252 }
4253 
4254 static journal_t *ext4_get_dev_journal(struct super_block *sb,
4255 				       dev_t j_dev)
4256 {
4257 	struct buffer_head *bh;
4258 	journal_t *journal;
4259 	ext4_fsblk_t start;
4260 	ext4_fsblk_t len;
4261 	int hblock, blocksize;
4262 	ext4_fsblk_t sb_block;
4263 	unsigned long offset;
4264 	struct ext4_super_block *es;
4265 	struct block_device *bdev;
4266 
4267 	BUG_ON(!ext4_has_feature_journal(sb));
4268 
4269 	bdev = ext4_blkdev_get(j_dev, sb);
4270 	if (bdev == NULL)
4271 		return NULL;
4272 
4273 	blocksize = sb->s_blocksize;
4274 	hblock = bdev_logical_block_size(bdev);
4275 	if (blocksize < hblock) {
4276 		ext4_msg(sb, KERN_ERR,
4277 			"blocksize too small for journal device");
4278 		goto out_bdev;
4279 	}
4280 
4281 	sb_block = EXT4_MIN_BLOCK_SIZE / blocksize;
4282 	offset = EXT4_MIN_BLOCK_SIZE % blocksize;
4283 	set_blocksize(bdev, blocksize);
4284 	if (!(bh = __bread(bdev, sb_block, blocksize))) {
4285 		ext4_msg(sb, KERN_ERR, "couldn't read superblock of "
4286 		       "external journal");
4287 		goto out_bdev;
4288 	}
4289 
4290 	es = (struct ext4_super_block *) (bh->b_data + offset);
4291 	if ((le16_to_cpu(es->s_magic) != EXT4_SUPER_MAGIC) ||
4292 	    !(le32_to_cpu(es->s_feature_incompat) &
4293 	      EXT4_FEATURE_INCOMPAT_JOURNAL_DEV)) {
4294 		ext4_msg(sb, KERN_ERR, "external journal has "
4295 					"bad superblock");
4296 		brelse(bh);
4297 		goto out_bdev;
4298 	}
4299 
4300 	if ((le32_to_cpu(es->s_feature_ro_compat) &
4301 	     EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
4302 	    es->s_checksum != ext4_superblock_csum(sb, es)) {
4303 		ext4_msg(sb, KERN_ERR, "external journal has "
4304 				       "corrupt superblock");
4305 		brelse(bh);
4306 		goto out_bdev;
4307 	}
4308 
4309 	if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
4310 		ext4_msg(sb, KERN_ERR, "journal UUID does not match");
4311 		brelse(bh);
4312 		goto out_bdev;
4313 	}
4314 
4315 	len = ext4_blocks_count(es);
4316 	start = sb_block + 1;
4317 	brelse(bh);	/* we're done with the superblock */
4318 
4319 	journal = jbd2_journal_init_dev(bdev, sb->s_bdev,
4320 					start, len, blocksize);
4321 	if (!journal) {
4322 		ext4_msg(sb, KERN_ERR, "failed to create device journal");
4323 		goto out_bdev;
4324 	}
4325 	journal->j_private = sb;
4326 	ll_rw_block(REQ_OP_READ, REQ_META | REQ_PRIO, 1, &journal->j_sb_buffer);
4327 	wait_on_buffer(journal->j_sb_buffer);
4328 	if (!buffer_uptodate(journal->j_sb_buffer)) {
4329 		ext4_msg(sb, KERN_ERR, "I/O error on journal device");
4330 		goto out_journal;
4331 	}
4332 	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
4333 		ext4_msg(sb, KERN_ERR, "External journal has more than one "
4334 					"user (unsupported) - %d",
4335 			be32_to_cpu(journal->j_superblock->s_nr_users));
4336 		goto out_journal;
4337 	}
4338 	EXT4_SB(sb)->journal_bdev = bdev;
4339 	ext4_init_journal_params(sb, journal);
4340 	return journal;
4341 
4342 out_journal:
4343 	jbd2_journal_destroy(journal);
4344 out_bdev:
4345 	ext4_blkdev_put(bdev);
4346 	return NULL;
4347 }
4348 
4349 static int ext4_load_journal(struct super_block *sb,
4350 			     struct ext4_super_block *es,
4351 			     unsigned long journal_devnum)
4352 {
4353 	journal_t *journal;
4354 	unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
4355 	dev_t journal_dev;
4356 	int err = 0;
4357 	int really_read_only;
4358 
4359 	BUG_ON(!ext4_has_feature_journal(sb));
4360 
4361 	if (journal_devnum &&
4362 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
4363 		ext4_msg(sb, KERN_INFO, "external journal device major/minor "
4364 			"numbers have changed");
4365 		journal_dev = new_decode_dev(journal_devnum);
4366 	} else
4367 		journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));
4368 
4369 	really_read_only = bdev_read_only(sb->s_bdev);
4370 
4371 	/*
4372 	 * Are we loading a blank journal or performing recovery after a
4373 	 * crash?  For recovery, we need to check in advance whether we
4374 	 * can get read-write access to the device.
4375 	 */
4376 	if (ext4_has_feature_journal_needs_recovery(sb)) {
4377 		if (sb->s_flags & MS_RDONLY) {
4378 			ext4_msg(sb, KERN_INFO, "INFO: recovery "
4379 					"required on readonly filesystem");
4380 			if (really_read_only) {
4381 				ext4_msg(sb, KERN_ERR, "write access "
4382 					"unavailable, cannot proceed");
4383 				return -EROFS;
4384 			}
4385 			ext4_msg(sb, KERN_INFO, "write access will "
4386 			       "be enabled during recovery");
4387 		}
4388 	}
4389 
4390 	if (journal_inum && journal_dev) {
4391 		ext4_msg(sb, KERN_ERR, "filesystem has both journal "
4392 		       "and inode journals!");
4393 		return -EINVAL;
4394 	}
4395 
4396 	if (journal_inum) {
4397 		if (!(journal = ext4_get_journal(sb, journal_inum)))
4398 			return -EINVAL;
4399 	} else {
4400 		if (!(journal = ext4_get_dev_journal(sb, journal_dev)))
4401 			return -EINVAL;
4402 	}
4403 
4404 	if (!(journal->j_flags & JBD2_BARRIER))
4405 		ext4_msg(sb, KERN_INFO, "barriers disabled");
4406 
4407 	if (!ext4_has_feature_journal_needs_recovery(sb))
4408 		err = jbd2_journal_wipe(journal, !really_read_only);
4409 	if (!err) {
4410 		char *save = kmalloc(EXT4_S_ERR_LEN, GFP_KERNEL);
4411 		if (save)
4412 			memcpy(save, ((char *) es) +
4413 			       EXT4_S_ERR_START, EXT4_S_ERR_LEN);
4414 		err = jbd2_journal_load(journal);
4415 		if (save)
4416 			memcpy(((char *) es) + EXT4_S_ERR_START,
4417 			       save, EXT4_S_ERR_LEN);
4418 		kfree(save);
4419 	}
4420 
4421 	if (err) {
4422 		ext4_msg(sb, KERN_ERR, "error loading journal");
4423 		jbd2_journal_destroy(journal);
4424 		return err;
4425 	}
4426 
4427 	EXT4_SB(sb)->s_journal = journal;
4428 	ext4_clear_journal_err(sb, es);
4429 
4430 	if (!really_read_only && journal_devnum &&
4431 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
4432 		es->s_journal_dev = cpu_to_le32(journal_devnum);
4433 
4434 		/* Make sure we flush the recovery flag to disk. */
4435 		ext4_commit_super(sb, 1);
4436 	}
4437 
4438 	return 0;
4439 }
4440 
4441 static int ext4_commit_super(struct super_block *sb, int sync)
4442 {
4443 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
4444 	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
4445 	int error = 0;
4446 
4447 	if (!sbh || block_device_ejected(sb))
4448 		return error;
4449 	/*
4450 	 * If the file system is mounted read-only, don't update the
4451 	 * superblock write time.  This avoids updating the superblock
4452 	 * write time when we are mounting the root file system
4453 	 * read/only but we need to replay the journal; at that point,
4454 	 * for people who are east of GMT and who make their clock
4455 	 * tick in localtime for Windows bug-for-bug compatibility,
4456 	 * the clock is set in the future, and this will cause e2fsck
4457 	 * to complain and force a full file system check.
4458 	 */
4459 	if (!(sb->s_flags & MS_RDONLY))
4460 		es->s_wtime = cpu_to_le32(get_seconds());
4461 	if (sb->s_bdev->bd_part)
4462 		es->s_kbytes_written =
4463 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written +
4464 			    ((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
4465 			      EXT4_SB(sb)->s_sectors_written_start) >> 1));
4466 	else
4467 		es->s_kbytes_written =
4468 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written);
4469 	if (percpu_counter_initialized(&EXT4_SB(sb)->s_freeclusters_counter))
4470 		ext4_free_blocks_count_set(es,
4471 			EXT4_C2B(EXT4_SB(sb), percpu_counter_sum_positive(
4472 				&EXT4_SB(sb)->s_freeclusters_counter)));
4473 	if (percpu_counter_initialized(&EXT4_SB(sb)->s_freeinodes_counter))
4474 		es->s_free_inodes_count =
4475 			cpu_to_le32(percpu_counter_sum_positive(
4476 				&EXT4_SB(sb)->s_freeinodes_counter));
4477 	BUFFER_TRACE(sbh, "marking dirty");
4478 	ext4_superblock_csum_set(sb);
4479 	lock_buffer(sbh);
4480 	if (buffer_write_io_error(sbh)) {
4481 		/*
4482 		 * Oh, dear.  A previous attempt to write the
4483 		 * superblock failed.  This could happen because the
4484 		 * USB device was yanked out.  Or it could happen to
4485 		 * be a transient write error and maybe the block will
4486 		 * be remapped.  Nothing we can do but to retry the
4487 		 * write and hope for the best.
4488 		 */
4489 		ext4_msg(sb, KERN_ERR, "previous I/O error to "
4490 		       "superblock detected");
4491 		clear_buffer_write_io_error(sbh);
4492 		set_buffer_uptodate(sbh);
4493 	}
4494 	mark_buffer_dirty(sbh);
4495 	unlock_buffer(sbh);
4496 	if (sync) {
4497 		error = __sync_dirty_buffer(sbh,
4498 			test_opt(sb, BARRIER) ? WRITE_FUA : WRITE_SYNC);
4499 		if (error)
4500 			return error;
4501 
4502 		error = buffer_write_io_error(sbh);
4503 		if (error) {
4504 			ext4_msg(sb, KERN_ERR, "I/O error while writing "
4505 			       "superblock");
4506 			clear_buffer_write_io_error(sbh);
4507 			set_buffer_uptodate(sbh);
4508 		}
4509 	}
4510 	return error;
4511 }
4512 
4513 /*
4514  * Have we just finished recovery?  If so, and if we are mounting (or
4515  * remounting) the filesystem readonly, then we will end up with a
4516  * consistent fs on disk.  Record that fact.
4517  */
4518 static void ext4_mark_recovery_complete(struct super_block *sb,
4519 					struct ext4_super_block *es)
4520 {
4521 	journal_t *journal = EXT4_SB(sb)->s_journal;
4522 
4523 	if (!ext4_has_feature_journal(sb)) {
4524 		BUG_ON(journal != NULL);
4525 		return;
4526 	}
4527 	jbd2_journal_lock_updates(journal);
4528 	if (jbd2_journal_flush(journal) < 0)
4529 		goto out;
4530 
4531 	if (ext4_has_feature_journal_needs_recovery(sb) &&
4532 	    sb->s_flags & MS_RDONLY) {
4533 		ext4_clear_feature_journal_needs_recovery(sb);
4534 		ext4_commit_super(sb, 1);
4535 	}
4536 
4537 out:
4538 	jbd2_journal_unlock_updates(journal);
4539 }
4540 
4541 /*
4542  * If we are mounting (or read-write remounting) a filesystem whose journal
4543  * has recorded an error from a previous lifetime, move that error to the
4544  * main filesystem now.
4545  */
4546 static void ext4_clear_journal_err(struct super_block *sb,
4547 				   struct ext4_super_block *es)
4548 {
4549 	journal_t *journal;
4550 	int j_errno;
4551 	const char *errstr;
4552 
4553 	BUG_ON(!ext4_has_feature_journal(sb));
4554 
4555 	journal = EXT4_SB(sb)->s_journal;
4556 
4557 	/*
4558 	 * Now check for any error status which may have been recorded in the
4559 	 * journal by a prior ext4_error() or ext4_abort()
4560 	 */
4561 
4562 	j_errno = jbd2_journal_errno(journal);
4563 	if (j_errno) {
4564 		char nbuf[16];
4565 
4566 		errstr = ext4_decode_error(sb, j_errno, nbuf);
4567 		ext4_warning(sb, "Filesystem error recorded "
4568 			     "from previous mount: %s", errstr);
4569 		ext4_warning(sb, "Marking fs in need of filesystem check.");
4570 
4571 		EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
4572 		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
4573 		ext4_commit_super(sb, 1);
4574 
4575 		jbd2_journal_clear_err(journal);
4576 		jbd2_journal_update_sb_errno(journal);
4577 	}
4578 }
4579 
4580 /*
4581  * Force the running and committing transactions to commit,
4582  * and wait on the commit.
4583  */
4584 int ext4_force_commit(struct super_block *sb)
4585 {
4586 	journal_t *journal;
4587 
4588 	if (sb->s_flags & MS_RDONLY)
4589 		return 0;
4590 
4591 	journal = EXT4_SB(sb)->s_journal;
4592 	return ext4_journal_force_commit(journal);
4593 }
4594 
4595 static int ext4_sync_fs(struct super_block *sb, int wait)
4596 {
4597 	int ret = 0;
4598 	tid_t target;
4599 	bool needs_barrier = false;
4600 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4601 
4602 	trace_ext4_sync_fs(sb, wait);
4603 	flush_workqueue(sbi->rsv_conversion_wq);
4604 	/*
4605 	 * Writeback quota in non-journalled quota case - journalled quota has
4606 	 * no dirty dquots
4607 	 */
4608 	dquot_writeback_dquots(sb, -1);
4609 	/*
4610 	 * Data writeback is possible w/o journal transaction, so barrier must
4611 	 * being sent at the end of the function. But we can skip it if
4612 	 * transaction_commit will do it for us.
4613 	 */
4614 	if (sbi->s_journal) {
4615 		target = jbd2_get_latest_transaction(sbi->s_journal);
4616 		if (wait && sbi->s_journal->j_flags & JBD2_BARRIER &&
4617 		    !jbd2_trans_will_send_data_barrier(sbi->s_journal, target))
4618 			needs_barrier = true;
4619 
4620 		if (jbd2_journal_start_commit(sbi->s_journal, &target)) {
4621 			if (wait)
4622 				ret = jbd2_log_wait_commit(sbi->s_journal,
4623 							   target);
4624 		}
4625 	} else if (wait && test_opt(sb, BARRIER))
4626 		needs_barrier = true;
4627 	if (needs_barrier) {
4628 		int err;
4629 		err = blkdev_issue_flush(sb->s_bdev, GFP_KERNEL, NULL);
4630 		if (!ret)
4631 			ret = err;
4632 	}
4633 
4634 	return ret;
4635 }
4636 
4637 /*
4638  * LVM calls this function before a (read-only) snapshot is created.  This
4639  * gives us a chance to flush the journal completely and mark the fs clean.
4640  *
4641  * Note that only this function cannot bring a filesystem to be in a clean
4642  * state independently. It relies on upper layer to stop all data & metadata
4643  * modifications.
4644  */
4645 static int ext4_freeze(struct super_block *sb)
4646 {
4647 	int error = 0;
4648 	journal_t *journal;
4649 
4650 	if (sb->s_flags & MS_RDONLY)
4651 		return 0;
4652 
4653 	journal = EXT4_SB(sb)->s_journal;
4654 
4655 	if (journal) {
4656 		/* Now we set up the journal barrier. */
4657 		jbd2_journal_lock_updates(journal);
4658 
4659 		/*
4660 		 * Don't clear the needs_recovery flag if we failed to
4661 		 * flush the journal.
4662 		 */
4663 		error = jbd2_journal_flush(journal);
4664 		if (error < 0)
4665 			goto out;
4666 
4667 		/* Journal blocked and flushed, clear needs_recovery flag. */
4668 		ext4_clear_feature_journal_needs_recovery(sb);
4669 	}
4670 
4671 	error = ext4_commit_super(sb, 1);
4672 out:
4673 	if (journal)
4674 		/* we rely on upper layer to stop further updates */
4675 		jbd2_journal_unlock_updates(journal);
4676 	return error;
4677 }
4678 
4679 /*
4680  * Called by LVM after the snapshot is done.  We need to reset the RECOVER
4681  * flag here, even though the filesystem is not technically dirty yet.
4682  */
4683 static int ext4_unfreeze(struct super_block *sb)
4684 {
4685 	if (sb->s_flags & MS_RDONLY)
4686 		return 0;
4687 
4688 	if (EXT4_SB(sb)->s_journal) {
4689 		/* Reset the needs_recovery flag before the fs is unlocked. */
4690 		ext4_set_feature_journal_needs_recovery(sb);
4691 	}
4692 
4693 	ext4_commit_super(sb, 1);
4694 	return 0;
4695 }
4696 
4697 /*
4698  * Structure to save mount options for ext4_remount's benefit
4699  */
4700 struct ext4_mount_options {
4701 	unsigned long s_mount_opt;
4702 	unsigned long s_mount_opt2;
4703 	kuid_t s_resuid;
4704 	kgid_t s_resgid;
4705 	unsigned long s_commit_interval;
4706 	u32 s_min_batch_time, s_max_batch_time;
4707 #ifdef CONFIG_QUOTA
4708 	int s_jquota_fmt;
4709 	char *s_qf_names[EXT4_MAXQUOTAS];
4710 #endif
4711 };
4712 
4713 static int ext4_remount(struct super_block *sb, int *flags, char *data)
4714 {
4715 	struct ext4_super_block *es;
4716 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4717 	unsigned long old_sb_flags;
4718 	struct ext4_mount_options old_opts;
4719 	int enable_quota = 0;
4720 	ext4_group_t g;
4721 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
4722 	int err = 0;
4723 #ifdef CONFIG_QUOTA
4724 	int i, j;
4725 #endif
4726 	char *orig_data = kstrdup(data, GFP_KERNEL);
4727 
4728 	/* Store the original options */
4729 	old_sb_flags = sb->s_flags;
4730 	old_opts.s_mount_opt = sbi->s_mount_opt;
4731 	old_opts.s_mount_opt2 = sbi->s_mount_opt2;
4732 	old_opts.s_resuid = sbi->s_resuid;
4733 	old_opts.s_resgid = sbi->s_resgid;
4734 	old_opts.s_commit_interval = sbi->s_commit_interval;
4735 	old_opts.s_min_batch_time = sbi->s_min_batch_time;
4736 	old_opts.s_max_batch_time = sbi->s_max_batch_time;
4737 #ifdef CONFIG_QUOTA
4738 	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
4739 	for (i = 0; i < EXT4_MAXQUOTAS; i++)
4740 		if (sbi->s_qf_names[i]) {
4741 			old_opts.s_qf_names[i] = kstrdup(sbi->s_qf_names[i],
4742 							 GFP_KERNEL);
4743 			if (!old_opts.s_qf_names[i]) {
4744 				for (j = 0; j < i; j++)
4745 					kfree(old_opts.s_qf_names[j]);
4746 				kfree(orig_data);
4747 				return -ENOMEM;
4748 			}
4749 		} else
4750 			old_opts.s_qf_names[i] = NULL;
4751 #endif
4752 	if (sbi->s_journal && sbi->s_journal->j_task->io_context)
4753 		journal_ioprio = sbi->s_journal->j_task->io_context->ioprio;
4754 
4755 	if (!parse_options(data, sb, NULL, &journal_ioprio, 1)) {
4756 		err = -EINVAL;
4757 		goto restore_opts;
4758 	}
4759 
4760 	if ((old_opts.s_mount_opt & EXT4_MOUNT_JOURNAL_CHECKSUM) ^
4761 	    test_opt(sb, JOURNAL_CHECKSUM)) {
4762 		ext4_msg(sb, KERN_ERR, "changing journal_checksum "
4763 			 "during remount not supported; ignoring");
4764 		sbi->s_mount_opt ^= EXT4_MOUNT_JOURNAL_CHECKSUM;
4765 	}
4766 
4767 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
4768 		if (test_opt2(sb, EXPLICIT_DELALLOC)) {
4769 			ext4_msg(sb, KERN_ERR, "can't mount with "
4770 				 "both data=journal and delalloc");
4771 			err = -EINVAL;
4772 			goto restore_opts;
4773 		}
4774 		if (test_opt(sb, DIOREAD_NOLOCK)) {
4775 			ext4_msg(sb, KERN_ERR, "can't mount with "
4776 				 "both data=journal and dioread_nolock");
4777 			err = -EINVAL;
4778 			goto restore_opts;
4779 		}
4780 		if (test_opt(sb, DAX)) {
4781 			ext4_msg(sb, KERN_ERR, "can't mount with "
4782 				 "both data=journal and dax");
4783 			err = -EINVAL;
4784 			goto restore_opts;
4785 		}
4786 	}
4787 
4788 	if ((sbi->s_mount_opt ^ old_opts.s_mount_opt) & EXT4_MOUNT_DAX) {
4789 		ext4_msg(sb, KERN_WARNING, "warning: refusing change of "
4790 			"dax flag with busy inodes while remounting");
4791 		sbi->s_mount_opt ^= EXT4_MOUNT_DAX;
4792 	}
4793 
4794 	if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
4795 		ext4_abort(sb, "Abort forced by user");
4796 
4797 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
4798 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
4799 
4800 	es = sbi->s_es;
4801 
4802 	if (sbi->s_journal) {
4803 		ext4_init_journal_params(sb, sbi->s_journal);
4804 		set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
4805 	}
4806 
4807 	if (*flags & MS_LAZYTIME)
4808 		sb->s_flags |= MS_LAZYTIME;
4809 
4810 	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY)) {
4811 		if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) {
4812 			err = -EROFS;
4813 			goto restore_opts;
4814 		}
4815 
4816 		if (*flags & MS_RDONLY) {
4817 			err = sync_filesystem(sb);
4818 			if (err < 0)
4819 				goto restore_opts;
4820 			err = dquot_suspend(sb, -1);
4821 			if (err < 0)
4822 				goto restore_opts;
4823 
4824 			/*
4825 			 * First of all, the unconditional stuff we have to do
4826 			 * to disable replay of the journal when we next remount
4827 			 */
4828 			sb->s_flags |= MS_RDONLY;
4829 
4830 			/*
4831 			 * OK, test if we are remounting a valid rw partition
4832 			 * readonly, and if so set the rdonly flag and then
4833 			 * mark the partition as valid again.
4834 			 */
4835 			if (!(es->s_state & cpu_to_le16(EXT4_VALID_FS)) &&
4836 			    (sbi->s_mount_state & EXT4_VALID_FS))
4837 				es->s_state = cpu_to_le16(sbi->s_mount_state);
4838 
4839 			if (sbi->s_journal)
4840 				ext4_mark_recovery_complete(sb, es);
4841 		} else {
4842 			/* Make sure we can mount this feature set readwrite */
4843 			if (ext4_has_feature_readonly(sb) ||
4844 			    !ext4_feature_set_ok(sb, 0)) {
4845 				err = -EROFS;
4846 				goto restore_opts;
4847 			}
4848 			/*
4849 			 * Make sure the group descriptor checksums
4850 			 * are sane.  If they aren't, refuse to remount r/w.
4851 			 */
4852 			for (g = 0; g < sbi->s_groups_count; g++) {
4853 				struct ext4_group_desc *gdp =
4854 					ext4_get_group_desc(sb, g, NULL);
4855 
4856 				if (!ext4_group_desc_csum_verify(sb, g, gdp)) {
4857 					ext4_msg(sb, KERN_ERR,
4858 	       "ext4_remount: Checksum for group %u failed (%u!=%u)",
4859 		g, le16_to_cpu(ext4_group_desc_csum(sb, g, gdp)),
4860 					       le16_to_cpu(gdp->bg_checksum));
4861 					err = -EFSBADCRC;
4862 					goto restore_opts;
4863 				}
4864 			}
4865 
4866 			/*
4867 			 * If we have an unprocessed orphan list hanging
4868 			 * around from a previously readonly bdev mount,
4869 			 * require a full umount/remount for now.
4870 			 */
4871 			if (es->s_last_orphan) {
4872 				ext4_msg(sb, KERN_WARNING, "Couldn't "
4873 				       "remount RDWR because of unprocessed "
4874 				       "orphan inode list.  Please "
4875 				       "umount/remount instead");
4876 				err = -EINVAL;
4877 				goto restore_opts;
4878 			}
4879 
4880 			/*
4881 			 * Mounting a RDONLY partition read-write, so reread
4882 			 * and store the current valid flag.  (It may have
4883 			 * been changed by e2fsck since we originally mounted
4884 			 * the partition.)
4885 			 */
4886 			if (sbi->s_journal)
4887 				ext4_clear_journal_err(sb, es);
4888 			sbi->s_mount_state = le16_to_cpu(es->s_state);
4889 			if (!ext4_setup_super(sb, es, 0))
4890 				sb->s_flags &= ~MS_RDONLY;
4891 			if (ext4_has_feature_mmp(sb))
4892 				if (ext4_multi_mount_protect(sb,
4893 						le64_to_cpu(es->s_mmp_block))) {
4894 					err = -EROFS;
4895 					goto restore_opts;
4896 				}
4897 			enable_quota = 1;
4898 		}
4899 	}
4900 
4901 	/*
4902 	 * Reinitialize lazy itable initialization thread based on
4903 	 * current settings
4904 	 */
4905 	if ((sb->s_flags & MS_RDONLY) || !test_opt(sb, INIT_INODE_TABLE))
4906 		ext4_unregister_li_request(sb);
4907 	else {
4908 		ext4_group_t first_not_zeroed;
4909 		first_not_zeroed = ext4_has_uninit_itable(sb);
4910 		ext4_register_li_request(sb, first_not_zeroed);
4911 	}
4912 
4913 	ext4_setup_system_zone(sb);
4914 	if (sbi->s_journal == NULL && !(old_sb_flags & MS_RDONLY))
4915 		ext4_commit_super(sb, 1);
4916 
4917 #ifdef CONFIG_QUOTA
4918 	/* Release old quota file names */
4919 	for (i = 0; i < EXT4_MAXQUOTAS; i++)
4920 		kfree(old_opts.s_qf_names[i]);
4921 	if (enable_quota) {
4922 		if (sb_any_quota_suspended(sb))
4923 			dquot_resume(sb, -1);
4924 		else if (ext4_has_feature_quota(sb)) {
4925 			err = ext4_enable_quotas(sb);
4926 			if (err)
4927 				goto restore_opts;
4928 		}
4929 	}
4930 #endif
4931 
4932 	*flags = (*flags & ~MS_LAZYTIME) | (sb->s_flags & MS_LAZYTIME);
4933 	ext4_msg(sb, KERN_INFO, "re-mounted. Opts: %s", orig_data);
4934 	kfree(orig_data);
4935 	return 0;
4936 
4937 restore_opts:
4938 	sb->s_flags = old_sb_flags;
4939 	sbi->s_mount_opt = old_opts.s_mount_opt;
4940 	sbi->s_mount_opt2 = old_opts.s_mount_opt2;
4941 	sbi->s_resuid = old_opts.s_resuid;
4942 	sbi->s_resgid = old_opts.s_resgid;
4943 	sbi->s_commit_interval = old_opts.s_commit_interval;
4944 	sbi->s_min_batch_time = old_opts.s_min_batch_time;
4945 	sbi->s_max_batch_time = old_opts.s_max_batch_time;
4946 #ifdef CONFIG_QUOTA
4947 	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
4948 	for (i = 0; i < EXT4_MAXQUOTAS; i++) {
4949 		kfree(sbi->s_qf_names[i]);
4950 		sbi->s_qf_names[i] = old_opts.s_qf_names[i];
4951 	}
4952 #endif
4953 	kfree(orig_data);
4954 	return err;
4955 }
4956 
4957 #ifdef CONFIG_QUOTA
4958 static int ext4_statfs_project(struct super_block *sb,
4959 			       kprojid_t projid, struct kstatfs *buf)
4960 {
4961 	struct kqid qid;
4962 	struct dquot *dquot;
4963 	u64 limit;
4964 	u64 curblock;
4965 
4966 	qid = make_kqid_projid(projid);
4967 	dquot = dqget(sb, qid);
4968 	if (IS_ERR(dquot))
4969 		return PTR_ERR(dquot);
4970 	spin_lock(&dq_data_lock);
4971 
4972 	limit = (dquot->dq_dqb.dqb_bsoftlimit ?
4973 		 dquot->dq_dqb.dqb_bsoftlimit :
4974 		 dquot->dq_dqb.dqb_bhardlimit) >> sb->s_blocksize_bits;
4975 	if (limit && buf->f_blocks > limit) {
4976 		curblock = dquot->dq_dqb.dqb_curspace >> sb->s_blocksize_bits;
4977 		buf->f_blocks = limit;
4978 		buf->f_bfree = buf->f_bavail =
4979 			(buf->f_blocks > curblock) ?
4980 			 (buf->f_blocks - curblock) : 0;
4981 	}
4982 
4983 	limit = dquot->dq_dqb.dqb_isoftlimit ?
4984 		dquot->dq_dqb.dqb_isoftlimit :
4985 		dquot->dq_dqb.dqb_ihardlimit;
4986 	if (limit && buf->f_files > limit) {
4987 		buf->f_files = limit;
4988 		buf->f_ffree =
4989 			(buf->f_files > dquot->dq_dqb.dqb_curinodes) ?
4990 			 (buf->f_files - dquot->dq_dqb.dqb_curinodes) : 0;
4991 	}
4992 
4993 	spin_unlock(&dq_data_lock);
4994 	dqput(dquot);
4995 	return 0;
4996 }
4997 #endif
4998 
4999 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
5000 {
5001 	struct super_block *sb = dentry->d_sb;
5002 	struct ext4_sb_info *sbi = EXT4_SB(sb);
5003 	struct ext4_super_block *es = sbi->s_es;
5004 	ext4_fsblk_t overhead = 0, resv_blocks;
5005 	u64 fsid;
5006 	s64 bfree;
5007 	resv_blocks = EXT4_C2B(sbi, atomic64_read(&sbi->s_resv_clusters));
5008 
5009 	if (!test_opt(sb, MINIX_DF))
5010 		overhead = sbi->s_overhead;
5011 
5012 	buf->f_type = EXT4_SUPER_MAGIC;
5013 	buf->f_bsize = sb->s_blocksize;
5014 	buf->f_blocks = ext4_blocks_count(es) - EXT4_C2B(sbi, overhead);
5015 	bfree = percpu_counter_sum_positive(&sbi->s_freeclusters_counter) -
5016 		percpu_counter_sum_positive(&sbi->s_dirtyclusters_counter);
5017 	/* prevent underflow in case that few free space is available */
5018 	buf->f_bfree = EXT4_C2B(sbi, max_t(s64, bfree, 0));
5019 	buf->f_bavail = buf->f_bfree -
5020 			(ext4_r_blocks_count(es) + resv_blocks);
5021 	if (buf->f_bfree < (ext4_r_blocks_count(es) + resv_blocks))
5022 		buf->f_bavail = 0;
5023 	buf->f_files = le32_to_cpu(es->s_inodes_count);
5024 	buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter);
5025 	buf->f_namelen = EXT4_NAME_LEN;
5026 	fsid = le64_to_cpup((void *)es->s_uuid) ^
5027 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
5028 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
5029 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
5030 
5031 #ifdef CONFIG_QUOTA
5032 	if (ext4_test_inode_flag(dentry->d_inode, EXT4_INODE_PROJINHERIT) &&
5033 	    sb_has_quota_limits_enabled(sb, PRJQUOTA))
5034 		ext4_statfs_project(sb, EXT4_I(dentry->d_inode)->i_projid, buf);
5035 #endif
5036 	return 0;
5037 }
5038 
5039 /* Helper function for writing quotas on sync - we need to start transaction
5040  * before quota file is locked for write. Otherwise the are possible deadlocks:
5041  * Process 1                         Process 2
5042  * ext4_create()                     quota_sync()
5043  *   jbd2_journal_start()                  write_dquot()
5044  *   dquot_initialize()                         down(dqio_mutex)
5045  *     down(dqio_mutex)                    jbd2_journal_start()
5046  *
5047  */
5048 
5049 #ifdef CONFIG_QUOTA
5050 
5051 static inline struct inode *dquot_to_inode(struct dquot *dquot)
5052 {
5053 	return sb_dqopt(dquot->dq_sb)->files[dquot->dq_id.type];
5054 }
5055 
5056 static int ext4_write_dquot(struct dquot *dquot)
5057 {
5058 	int ret, err;
5059 	handle_t *handle;
5060 	struct inode *inode;
5061 
5062 	inode = dquot_to_inode(dquot);
5063 	handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
5064 				    EXT4_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
5065 	if (IS_ERR(handle))
5066 		return PTR_ERR(handle);
5067 	ret = dquot_commit(dquot);
5068 	err = ext4_journal_stop(handle);
5069 	if (!ret)
5070 		ret = err;
5071 	return ret;
5072 }
5073 
5074 static int ext4_acquire_dquot(struct dquot *dquot)
5075 {
5076 	int ret, err;
5077 	handle_t *handle;
5078 
5079 	handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
5080 				    EXT4_QUOTA_INIT_BLOCKS(dquot->dq_sb));
5081 	if (IS_ERR(handle))
5082 		return PTR_ERR(handle);
5083 	ret = dquot_acquire(dquot);
5084 	err = ext4_journal_stop(handle);
5085 	if (!ret)
5086 		ret = err;
5087 	return ret;
5088 }
5089 
5090 static int ext4_release_dquot(struct dquot *dquot)
5091 {
5092 	int ret, err;
5093 	handle_t *handle;
5094 
5095 	handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
5096 				    EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
5097 	if (IS_ERR(handle)) {
5098 		/* Release dquot anyway to avoid endless cycle in dqput() */
5099 		dquot_release(dquot);
5100 		return PTR_ERR(handle);
5101 	}
5102 	ret = dquot_release(dquot);
5103 	err = ext4_journal_stop(handle);
5104 	if (!ret)
5105 		ret = err;
5106 	return ret;
5107 }
5108 
5109 static int ext4_mark_dquot_dirty(struct dquot *dquot)
5110 {
5111 	struct super_block *sb = dquot->dq_sb;
5112 	struct ext4_sb_info *sbi = EXT4_SB(sb);
5113 
5114 	/* Are we journaling quotas? */
5115 	if (ext4_has_feature_quota(sb) ||
5116 	    sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
5117 		dquot_mark_dquot_dirty(dquot);
5118 		return ext4_write_dquot(dquot);
5119 	} else {
5120 		return dquot_mark_dquot_dirty(dquot);
5121 	}
5122 }
5123 
5124 static int ext4_write_info(struct super_block *sb, int type)
5125 {
5126 	int ret, err;
5127 	handle_t *handle;
5128 
5129 	/* Data block + inode block */
5130 	handle = ext4_journal_start(d_inode(sb->s_root), EXT4_HT_QUOTA, 2);
5131 	if (IS_ERR(handle))
5132 		return PTR_ERR(handle);
5133 	ret = dquot_commit_info(sb, type);
5134 	err = ext4_journal_stop(handle);
5135 	if (!ret)
5136 		ret = err;
5137 	return ret;
5138 }
5139 
5140 /*
5141  * Turn on quotas during mount time - we need to find
5142  * the quota file and such...
5143  */
5144 static int ext4_quota_on_mount(struct super_block *sb, int type)
5145 {
5146 	return dquot_quota_on_mount(sb, EXT4_SB(sb)->s_qf_names[type],
5147 					EXT4_SB(sb)->s_jquota_fmt, type);
5148 }
5149 
5150 static void lockdep_set_quota_inode(struct inode *inode, int subclass)
5151 {
5152 	struct ext4_inode_info *ei = EXT4_I(inode);
5153 
5154 	/* The first argument of lockdep_set_subclass has to be
5155 	 * *exactly* the same as the argument to init_rwsem() --- in
5156 	 * this case, in init_once() --- or lockdep gets unhappy
5157 	 * because the name of the lock is set using the
5158 	 * stringification of the argument to init_rwsem().
5159 	 */
5160 	(void) ei;	/* shut up clang warning if !CONFIG_LOCKDEP */
5161 	lockdep_set_subclass(&ei->i_data_sem, subclass);
5162 }
5163 
5164 /*
5165  * Standard function to be called on quota_on
5166  */
5167 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
5168 			 struct path *path)
5169 {
5170 	int err;
5171 
5172 	if (!test_opt(sb, QUOTA))
5173 		return -EINVAL;
5174 
5175 	/* Quotafile not on the same filesystem? */
5176 	if (path->dentry->d_sb != sb)
5177 		return -EXDEV;
5178 	/* Journaling quota? */
5179 	if (EXT4_SB(sb)->s_qf_names[type]) {
5180 		/* Quotafile not in fs root? */
5181 		if (path->dentry->d_parent != sb->s_root)
5182 			ext4_msg(sb, KERN_WARNING,
5183 				"Quota file not on filesystem root. "
5184 				"Journaled quota will not work");
5185 	}
5186 
5187 	/*
5188 	 * When we journal data on quota file, we have to flush journal to see
5189 	 * all updates to the file when we bypass pagecache...
5190 	 */
5191 	if (EXT4_SB(sb)->s_journal &&
5192 	    ext4_should_journal_data(d_inode(path->dentry))) {
5193 		/*
5194 		 * We don't need to lock updates but journal_flush() could
5195 		 * otherwise be livelocked...
5196 		 */
5197 		jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
5198 		err = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
5199 		jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
5200 		if (err)
5201 			return err;
5202 	}
5203 	lockdep_set_quota_inode(path->dentry->d_inode, I_DATA_SEM_QUOTA);
5204 	err = dquot_quota_on(sb, type, format_id, path);
5205 	if (err)
5206 		lockdep_set_quota_inode(path->dentry->d_inode,
5207 					     I_DATA_SEM_NORMAL);
5208 	return err;
5209 }
5210 
5211 static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
5212 			     unsigned int flags)
5213 {
5214 	int err;
5215 	struct inode *qf_inode;
5216 	unsigned long qf_inums[EXT4_MAXQUOTAS] = {
5217 		le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
5218 		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum),
5219 		le32_to_cpu(EXT4_SB(sb)->s_es->s_prj_quota_inum)
5220 	};
5221 
5222 	BUG_ON(!ext4_has_feature_quota(sb));
5223 
5224 	if (!qf_inums[type])
5225 		return -EPERM;
5226 
5227 	qf_inode = ext4_iget(sb, qf_inums[type]);
5228 	if (IS_ERR(qf_inode)) {
5229 		ext4_error(sb, "Bad quota inode # %lu", qf_inums[type]);
5230 		return PTR_ERR(qf_inode);
5231 	}
5232 
5233 	/* Don't account quota for quota files to avoid recursion */
5234 	qf_inode->i_flags |= S_NOQUOTA;
5235 	lockdep_set_quota_inode(qf_inode, I_DATA_SEM_QUOTA);
5236 	err = dquot_enable(qf_inode, type, format_id, flags);
5237 	iput(qf_inode);
5238 	if (err)
5239 		lockdep_set_quota_inode(qf_inode, I_DATA_SEM_NORMAL);
5240 
5241 	return err;
5242 }
5243 
5244 /* Enable usage tracking for all quota types. */
5245 static int ext4_enable_quotas(struct super_block *sb)
5246 {
5247 	int type, err = 0;
5248 	unsigned long qf_inums[EXT4_MAXQUOTAS] = {
5249 		le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
5250 		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum),
5251 		le32_to_cpu(EXT4_SB(sb)->s_es->s_prj_quota_inum)
5252 	};
5253 
5254 	sb_dqopt(sb)->flags |= DQUOT_QUOTA_SYS_FILE;
5255 	for (type = 0; type < EXT4_MAXQUOTAS; type++) {
5256 		if (qf_inums[type]) {
5257 			err = ext4_quota_enable(sb, type, QFMT_VFS_V1,
5258 						DQUOT_USAGE_ENABLED);
5259 			if (err) {
5260 				ext4_warning(sb,
5261 					"Failed to enable quota tracking "
5262 					"(type=%d, err=%d). Please run "
5263 					"e2fsck to fix.", type, err);
5264 				return err;
5265 			}
5266 		}
5267 	}
5268 	return 0;
5269 }
5270 
5271 static int ext4_quota_off(struct super_block *sb, int type)
5272 {
5273 	struct inode *inode = sb_dqopt(sb)->files[type];
5274 	handle_t *handle;
5275 
5276 	/* Force all delayed allocation blocks to be allocated.
5277 	 * Caller already holds s_umount sem */
5278 	if (test_opt(sb, DELALLOC))
5279 		sync_filesystem(sb);
5280 
5281 	if (!inode)
5282 		goto out;
5283 
5284 	/* Update modification times of quota files when userspace can
5285 	 * start looking at them */
5286 	handle = ext4_journal_start(inode, EXT4_HT_QUOTA, 1);
5287 	if (IS_ERR(handle))
5288 		goto out;
5289 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
5290 	ext4_mark_inode_dirty(handle, inode);
5291 	ext4_journal_stop(handle);
5292 
5293 out:
5294 	return dquot_quota_off(sb, type);
5295 }
5296 
5297 /* Read data from quotafile - avoid pagecache and such because we cannot afford
5298  * acquiring the locks... As quota files are never truncated and quota code
5299  * itself serializes the operations (and no one else should touch the files)
5300  * we don't have to be afraid of races */
5301 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
5302 			       size_t len, loff_t off)
5303 {
5304 	struct inode *inode = sb_dqopt(sb)->files[type];
5305 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
5306 	int offset = off & (sb->s_blocksize - 1);
5307 	int tocopy;
5308 	size_t toread;
5309 	struct buffer_head *bh;
5310 	loff_t i_size = i_size_read(inode);
5311 
5312 	if (off > i_size)
5313 		return 0;
5314 	if (off+len > i_size)
5315 		len = i_size-off;
5316 	toread = len;
5317 	while (toread > 0) {
5318 		tocopy = sb->s_blocksize - offset < toread ?
5319 				sb->s_blocksize - offset : toread;
5320 		bh = ext4_bread(NULL, inode, blk, 0);
5321 		if (IS_ERR(bh))
5322 			return PTR_ERR(bh);
5323 		if (!bh)	/* A hole? */
5324 			memset(data, 0, tocopy);
5325 		else
5326 			memcpy(data, bh->b_data+offset, tocopy);
5327 		brelse(bh);
5328 		offset = 0;
5329 		toread -= tocopy;
5330 		data += tocopy;
5331 		blk++;
5332 	}
5333 	return len;
5334 }
5335 
5336 /* Write to quotafile (we know the transaction is already started and has
5337  * enough credits) */
5338 static ssize_t ext4_quota_write(struct super_block *sb, int type,
5339 				const char *data, size_t len, loff_t off)
5340 {
5341 	struct inode *inode = sb_dqopt(sb)->files[type];
5342 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
5343 	int err, offset = off & (sb->s_blocksize - 1);
5344 	int retries = 0;
5345 	struct buffer_head *bh;
5346 	handle_t *handle = journal_current_handle();
5347 
5348 	if (EXT4_SB(sb)->s_journal && !handle) {
5349 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
5350 			" cancelled because transaction is not started",
5351 			(unsigned long long)off, (unsigned long long)len);
5352 		return -EIO;
5353 	}
5354 	/*
5355 	 * Since we account only one data block in transaction credits,
5356 	 * then it is impossible to cross a block boundary.
5357 	 */
5358 	if (sb->s_blocksize - offset < len) {
5359 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
5360 			" cancelled because not block aligned",
5361 			(unsigned long long)off, (unsigned long long)len);
5362 		return -EIO;
5363 	}
5364 
5365 	do {
5366 		bh = ext4_bread(handle, inode, blk,
5367 				EXT4_GET_BLOCKS_CREATE |
5368 				EXT4_GET_BLOCKS_METADATA_NOFAIL);
5369 	} while (IS_ERR(bh) && (PTR_ERR(bh) == -ENOSPC) &&
5370 		 ext4_should_retry_alloc(inode->i_sb, &retries));
5371 	if (IS_ERR(bh))
5372 		return PTR_ERR(bh);
5373 	if (!bh)
5374 		goto out;
5375 	BUFFER_TRACE(bh, "get write access");
5376 	err = ext4_journal_get_write_access(handle, bh);
5377 	if (err) {
5378 		brelse(bh);
5379 		return err;
5380 	}
5381 	lock_buffer(bh);
5382 	memcpy(bh->b_data+offset, data, len);
5383 	flush_dcache_page(bh->b_page);
5384 	unlock_buffer(bh);
5385 	err = ext4_handle_dirty_metadata(handle, NULL, bh);
5386 	brelse(bh);
5387 out:
5388 	if (inode->i_size < off + len) {
5389 		i_size_write(inode, off + len);
5390 		EXT4_I(inode)->i_disksize = inode->i_size;
5391 		ext4_mark_inode_dirty(handle, inode);
5392 	}
5393 	return len;
5394 }
5395 
5396 static int ext4_get_next_id(struct super_block *sb, struct kqid *qid)
5397 {
5398 	const struct quota_format_ops	*ops;
5399 
5400 	if (!sb_has_quota_loaded(sb, qid->type))
5401 		return -ESRCH;
5402 	ops = sb_dqopt(sb)->ops[qid->type];
5403 	if (!ops || !ops->get_next_id)
5404 		return -ENOSYS;
5405 	return dquot_get_next_id(sb, qid);
5406 }
5407 #endif
5408 
5409 static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
5410 		       const char *dev_name, void *data)
5411 {
5412 	return mount_bdev(fs_type, flags, dev_name, data, ext4_fill_super);
5413 }
5414 
5415 #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT2)
5416 static inline void register_as_ext2(void)
5417 {
5418 	int err = register_filesystem(&ext2_fs_type);
5419 	if (err)
5420 		printk(KERN_WARNING
5421 		       "EXT4-fs: Unable to register as ext2 (%d)\n", err);
5422 }
5423 
5424 static inline void unregister_as_ext2(void)
5425 {
5426 	unregister_filesystem(&ext2_fs_type);
5427 }
5428 
5429 static inline int ext2_feature_set_ok(struct super_block *sb)
5430 {
5431 	if (ext4_has_unknown_ext2_incompat_features(sb))
5432 		return 0;
5433 	if (sb->s_flags & MS_RDONLY)
5434 		return 1;
5435 	if (ext4_has_unknown_ext2_ro_compat_features(sb))
5436 		return 0;
5437 	return 1;
5438 }
5439 #else
5440 static inline void register_as_ext2(void) { }
5441 static inline void unregister_as_ext2(void) { }
5442 static inline int ext2_feature_set_ok(struct super_block *sb) { return 0; }
5443 #endif
5444 
5445 static inline void register_as_ext3(void)
5446 {
5447 	int err = register_filesystem(&ext3_fs_type);
5448 	if (err)
5449 		printk(KERN_WARNING
5450 		       "EXT4-fs: Unable to register as ext3 (%d)\n", err);
5451 }
5452 
5453 static inline void unregister_as_ext3(void)
5454 {
5455 	unregister_filesystem(&ext3_fs_type);
5456 }
5457 
5458 static inline int ext3_feature_set_ok(struct super_block *sb)
5459 {
5460 	if (ext4_has_unknown_ext3_incompat_features(sb))
5461 		return 0;
5462 	if (!ext4_has_feature_journal(sb))
5463 		return 0;
5464 	if (sb->s_flags & MS_RDONLY)
5465 		return 1;
5466 	if (ext4_has_unknown_ext3_ro_compat_features(sb))
5467 		return 0;
5468 	return 1;
5469 }
5470 
5471 static struct file_system_type ext4_fs_type = {
5472 	.owner		= THIS_MODULE,
5473 	.name		= "ext4",
5474 	.mount		= ext4_mount,
5475 	.kill_sb	= kill_block_super,
5476 	.fs_flags	= FS_REQUIRES_DEV,
5477 };
5478 MODULE_ALIAS_FS("ext4");
5479 
5480 /* Shared across all ext4 file systems */
5481 wait_queue_head_t ext4__ioend_wq[EXT4_WQ_HASH_SZ];
5482 
5483 static int __init ext4_init_fs(void)
5484 {
5485 	int i, err;
5486 
5487 	ratelimit_state_init(&ext4_mount_msg_ratelimit, 30 * HZ, 64);
5488 	ext4_li_info = NULL;
5489 	mutex_init(&ext4_li_mtx);
5490 
5491 	/* Build-time check for flags consistency */
5492 	ext4_check_flag_values();
5493 
5494 	for (i = 0; i < EXT4_WQ_HASH_SZ; i++)
5495 		init_waitqueue_head(&ext4__ioend_wq[i]);
5496 
5497 	err = ext4_init_es();
5498 	if (err)
5499 		return err;
5500 
5501 	err = ext4_init_pageio();
5502 	if (err)
5503 		goto out5;
5504 
5505 	err = ext4_init_system_zone();
5506 	if (err)
5507 		goto out4;
5508 
5509 	err = ext4_init_sysfs();
5510 	if (err)
5511 		goto out3;
5512 
5513 	err = ext4_init_mballoc();
5514 	if (err)
5515 		goto out2;
5516 	err = init_inodecache();
5517 	if (err)
5518 		goto out1;
5519 	register_as_ext3();
5520 	register_as_ext2();
5521 	err = register_filesystem(&ext4_fs_type);
5522 	if (err)
5523 		goto out;
5524 
5525 	return 0;
5526 out:
5527 	unregister_as_ext2();
5528 	unregister_as_ext3();
5529 	destroy_inodecache();
5530 out1:
5531 	ext4_exit_mballoc();
5532 out2:
5533 	ext4_exit_sysfs();
5534 out3:
5535 	ext4_exit_system_zone();
5536 out4:
5537 	ext4_exit_pageio();
5538 out5:
5539 	ext4_exit_es();
5540 
5541 	return err;
5542 }
5543 
5544 static void __exit ext4_exit_fs(void)
5545 {
5546 	ext4_destroy_lazyinit_thread();
5547 	unregister_as_ext2();
5548 	unregister_as_ext3();
5549 	unregister_filesystem(&ext4_fs_type);
5550 	destroy_inodecache();
5551 	ext4_exit_mballoc();
5552 	ext4_exit_sysfs();
5553 	ext4_exit_system_zone();
5554 	ext4_exit_pageio();
5555 	ext4_exit_es();
5556 }
5557 
5558 MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
5559 MODULE_DESCRIPTION("Fourth Extended Filesystem");
5560 MODULE_LICENSE("GPL");
5561 module_init(ext4_init_fs)
5562 module_exit(ext4_exit_fs)
5563