xref: /openbmc/linux/fs/ext4/super.c (revision 3e26a691)
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 	brelse(sbi->s_sbh);
863 #ifdef CONFIG_QUOTA
864 	for (i = 0; i < EXT4_MAXQUOTAS; i++)
865 		kfree(sbi->s_qf_names[i]);
866 #endif
867 
868 	/* Debugging code just in case the in-memory inode orphan list
869 	 * isn't empty.  The on-disk one can be non-empty if we've
870 	 * detected an error and taken the fs readonly, but the
871 	 * in-memory list had better be clean by this point. */
872 	if (!list_empty(&sbi->s_orphan))
873 		dump_orphan_list(sb, sbi);
874 	J_ASSERT(list_empty(&sbi->s_orphan));
875 
876 	sync_blockdev(sb->s_bdev);
877 	invalidate_bdev(sb->s_bdev);
878 	if (sbi->journal_bdev && sbi->journal_bdev != sb->s_bdev) {
879 		/*
880 		 * Invalidate the journal device's buffers.  We don't want them
881 		 * floating about in memory - the physical journal device may
882 		 * hotswapped, and it breaks the `ro-after' testing code.
883 		 */
884 		sync_blockdev(sbi->journal_bdev);
885 		invalidate_bdev(sbi->journal_bdev);
886 		ext4_blkdev_remove(sbi);
887 	}
888 	if (sbi->s_mb_cache) {
889 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
890 		sbi->s_mb_cache = NULL;
891 	}
892 	if (sbi->s_mmp_tsk)
893 		kthread_stop(sbi->s_mmp_tsk);
894 	sb->s_fs_info = NULL;
895 	/*
896 	 * Now that we are completely done shutting down the
897 	 * superblock, we need to actually destroy the kobject.
898 	 */
899 	kobject_put(&sbi->s_kobj);
900 	wait_for_completion(&sbi->s_kobj_unregister);
901 	if (sbi->s_chksum_driver)
902 		crypto_free_shash(sbi->s_chksum_driver);
903 	kfree(sbi->s_blockgroup_lock);
904 	kfree(sbi);
905 }
906 
907 static struct kmem_cache *ext4_inode_cachep;
908 
909 /*
910  * Called inside transaction, so use GFP_NOFS
911  */
912 static struct inode *ext4_alloc_inode(struct super_block *sb)
913 {
914 	struct ext4_inode_info *ei;
915 
916 	ei = kmem_cache_alloc(ext4_inode_cachep, GFP_NOFS);
917 	if (!ei)
918 		return NULL;
919 
920 	ei->vfs_inode.i_version = 1;
921 	spin_lock_init(&ei->i_raw_lock);
922 	INIT_LIST_HEAD(&ei->i_prealloc_list);
923 	spin_lock_init(&ei->i_prealloc_lock);
924 	ext4_es_init_tree(&ei->i_es_tree);
925 	rwlock_init(&ei->i_es_lock);
926 	INIT_LIST_HEAD(&ei->i_es_list);
927 	ei->i_es_all_nr = 0;
928 	ei->i_es_shk_nr = 0;
929 	ei->i_es_shrink_lblk = 0;
930 	ei->i_reserved_data_blocks = 0;
931 	ei->i_reserved_meta_blocks = 0;
932 	ei->i_allocated_meta_blocks = 0;
933 	ei->i_da_metadata_calc_len = 0;
934 	ei->i_da_metadata_calc_last_lblock = 0;
935 	spin_lock_init(&(ei->i_block_reservation_lock));
936 #ifdef CONFIG_QUOTA
937 	ei->i_reserved_quota = 0;
938 	memset(&ei->i_dquot, 0, sizeof(ei->i_dquot));
939 #endif
940 	ei->jinode = NULL;
941 	INIT_LIST_HEAD(&ei->i_rsv_conversion_list);
942 	spin_lock_init(&ei->i_completed_io_lock);
943 	ei->i_sync_tid = 0;
944 	ei->i_datasync_tid = 0;
945 	atomic_set(&ei->i_unwritten, 0);
946 	INIT_WORK(&ei->i_rsv_conversion_work, ext4_end_io_rsv_work);
947 #ifdef CONFIG_EXT4_FS_ENCRYPTION
948 	ei->i_crypt_info = NULL;
949 #endif
950 	return &ei->vfs_inode;
951 }
952 
953 static int ext4_drop_inode(struct inode *inode)
954 {
955 	int drop = generic_drop_inode(inode);
956 
957 	trace_ext4_drop_inode(inode, drop);
958 	return drop;
959 }
960 
961 static void ext4_i_callback(struct rcu_head *head)
962 {
963 	struct inode *inode = container_of(head, struct inode, i_rcu);
964 	kmem_cache_free(ext4_inode_cachep, EXT4_I(inode));
965 }
966 
967 static void ext4_destroy_inode(struct inode *inode)
968 {
969 	if (!list_empty(&(EXT4_I(inode)->i_orphan))) {
970 		ext4_msg(inode->i_sb, KERN_ERR,
971 			 "Inode %lu (%p): orphan list check failed!",
972 			 inode->i_ino, EXT4_I(inode));
973 		print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 16, 4,
974 				EXT4_I(inode), sizeof(struct ext4_inode_info),
975 				true);
976 		dump_stack();
977 	}
978 	call_rcu(&inode->i_rcu, ext4_i_callback);
979 }
980 
981 static void init_once(void *foo)
982 {
983 	struct ext4_inode_info *ei = (struct ext4_inode_info *) foo;
984 
985 	INIT_LIST_HEAD(&ei->i_orphan);
986 	init_rwsem(&ei->xattr_sem);
987 	init_rwsem(&ei->i_data_sem);
988 	init_rwsem(&ei->i_mmap_sem);
989 	inode_init_once(&ei->vfs_inode);
990 }
991 
992 static int __init init_inodecache(void)
993 {
994 	ext4_inode_cachep = kmem_cache_create("ext4_inode_cache",
995 					     sizeof(struct ext4_inode_info),
996 					     0, (SLAB_RECLAIM_ACCOUNT|
997 						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
998 					     init_once);
999 	if (ext4_inode_cachep == NULL)
1000 		return -ENOMEM;
1001 	return 0;
1002 }
1003 
1004 static void destroy_inodecache(void)
1005 {
1006 	/*
1007 	 * Make sure all delayed rcu free inodes are flushed before we
1008 	 * destroy cache.
1009 	 */
1010 	rcu_barrier();
1011 	kmem_cache_destroy(ext4_inode_cachep);
1012 }
1013 
1014 void ext4_clear_inode(struct inode *inode)
1015 {
1016 	invalidate_inode_buffers(inode);
1017 	clear_inode(inode);
1018 	dquot_drop(inode);
1019 	ext4_discard_preallocations(inode);
1020 	ext4_es_remove_extent(inode, 0, EXT_MAX_BLOCKS);
1021 	if (EXT4_I(inode)->jinode) {
1022 		jbd2_journal_release_jbd_inode(EXT4_JOURNAL(inode),
1023 					       EXT4_I(inode)->jinode);
1024 		jbd2_free_inode(EXT4_I(inode)->jinode);
1025 		EXT4_I(inode)->jinode = NULL;
1026 	}
1027 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1028 	if (EXT4_I(inode)->i_crypt_info)
1029 		ext4_free_encryption_info(inode, EXT4_I(inode)->i_crypt_info);
1030 #endif
1031 }
1032 
1033 static struct inode *ext4_nfs_get_inode(struct super_block *sb,
1034 					u64 ino, u32 generation)
1035 {
1036 	struct inode *inode;
1037 
1038 	if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
1039 		return ERR_PTR(-ESTALE);
1040 	if (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
1041 		return ERR_PTR(-ESTALE);
1042 
1043 	/* iget isn't really right if the inode is currently unallocated!!
1044 	 *
1045 	 * ext4_read_inode will return a bad_inode if the inode had been
1046 	 * deleted, so we should be safe.
1047 	 *
1048 	 * Currently we don't know the generation for parent directory, so
1049 	 * a generation of 0 means "accept any"
1050 	 */
1051 	inode = ext4_iget_normal(sb, ino);
1052 	if (IS_ERR(inode))
1053 		return ERR_CAST(inode);
1054 	if (generation && inode->i_generation != generation) {
1055 		iput(inode);
1056 		return ERR_PTR(-ESTALE);
1057 	}
1058 
1059 	return inode;
1060 }
1061 
1062 static struct dentry *ext4_fh_to_dentry(struct super_block *sb, struct fid *fid,
1063 					int fh_len, int fh_type)
1064 {
1065 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
1066 				    ext4_nfs_get_inode);
1067 }
1068 
1069 static struct dentry *ext4_fh_to_parent(struct super_block *sb, struct fid *fid,
1070 					int fh_len, int fh_type)
1071 {
1072 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
1073 				    ext4_nfs_get_inode);
1074 }
1075 
1076 /*
1077  * Try to release metadata pages (indirect blocks, directories) which are
1078  * mapped via the block device.  Since these pages could have journal heads
1079  * which would prevent try_to_free_buffers() from freeing them, we must use
1080  * jbd2 layer's try_to_free_buffers() function to release them.
1081  */
1082 static int bdev_try_to_free_page(struct super_block *sb, struct page *page,
1083 				 gfp_t wait)
1084 {
1085 	journal_t *journal = EXT4_SB(sb)->s_journal;
1086 
1087 	WARN_ON(PageChecked(page));
1088 	if (!page_has_buffers(page))
1089 		return 0;
1090 	if (journal)
1091 		return jbd2_journal_try_to_free_buffers(journal, page,
1092 						wait & ~__GFP_DIRECT_RECLAIM);
1093 	return try_to_free_buffers(page);
1094 }
1095 
1096 #ifdef CONFIG_QUOTA
1097 static char *quotatypes[] = INITQFNAMES;
1098 #define QTYPE2NAME(t) (quotatypes[t])
1099 
1100 static int ext4_write_dquot(struct dquot *dquot);
1101 static int ext4_acquire_dquot(struct dquot *dquot);
1102 static int ext4_release_dquot(struct dquot *dquot);
1103 static int ext4_mark_dquot_dirty(struct dquot *dquot);
1104 static int ext4_write_info(struct super_block *sb, int type);
1105 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
1106 			 struct path *path);
1107 static int ext4_quota_off(struct super_block *sb, int type);
1108 static int ext4_quota_on_mount(struct super_block *sb, int type);
1109 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
1110 			       size_t len, loff_t off);
1111 static ssize_t ext4_quota_write(struct super_block *sb, int type,
1112 				const char *data, size_t len, loff_t off);
1113 static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
1114 			     unsigned int flags);
1115 static int ext4_enable_quotas(struct super_block *sb);
1116 
1117 static struct dquot **ext4_get_dquots(struct inode *inode)
1118 {
1119 	return EXT4_I(inode)->i_dquot;
1120 }
1121 
1122 static const struct dquot_operations ext4_quota_operations = {
1123 	.get_reserved_space = ext4_get_reserved_space,
1124 	.write_dquot	= ext4_write_dquot,
1125 	.acquire_dquot	= ext4_acquire_dquot,
1126 	.release_dquot	= ext4_release_dquot,
1127 	.mark_dirty	= ext4_mark_dquot_dirty,
1128 	.write_info	= ext4_write_info,
1129 	.alloc_dquot	= dquot_alloc,
1130 	.destroy_dquot	= dquot_destroy,
1131 	.get_projid	= ext4_get_projid,
1132 	.get_next_id	= dquot_get_next_id,
1133 };
1134 
1135 static const struct quotactl_ops ext4_qctl_operations = {
1136 	.quota_on	= ext4_quota_on,
1137 	.quota_off	= ext4_quota_off,
1138 	.quota_sync	= dquot_quota_sync,
1139 	.get_state	= dquot_get_state,
1140 	.set_info	= dquot_set_dqinfo,
1141 	.get_dqblk	= dquot_get_dqblk,
1142 	.set_dqblk	= dquot_set_dqblk,
1143 	.get_nextdqblk	= dquot_get_next_dqblk,
1144 };
1145 #endif
1146 
1147 static const struct super_operations ext4_sops = {
1148 	.alloc_inode	= ext4_alloc_inode,
1149 	.destroy_inode	= ext4_destroy_inode,
1150 	.write_inode	= ext4_write_inode,
1151 	.dirty_inode	= ext4_dirty_inode,
1152 	.drop_inode	= ext4_drop_inode,
1153 	.evict_inode	= ext4_evict_inode,
1154 	.put_super	= ext4_put_super,
1155 	.sync_fs	= ext4_sync_fs,
1156 	.freeze_fs	= ext4_freeze,
1157 	.unfreeze_fs	= ext4_unfreeze,
1158 	.statfs		= ext4_statfs,
1159 	.remount_fs	= ext4_remount,
1160 	.show_options	= ext4_show_options,
1161 #ifdef CONFIG_QUOTA
1162 	.quota_read	= ext4_quota_read,
1163 	.quota_write	= ext4_quota_write,
1164 	.get_dquots	= ext4_get_dquots,
1165 #endif
1166 	.bdev_try_to_free_page = bdev_try_to_free_page,
1167 };
1168 
1169 static const struct export_operations ext4_export_ops = {
1170 	.fh_to_dentry = ext4_fh_to_dentry,
1171 	.fh_to_parent = ext4_fh_to_parent,
1172 	.get_parent = ext4_get_parent,
1173 };
1174 
1175 enum {
1176 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
1177 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
1178 	Opt_nouid32, Opt_debug, Opt_removed,
1179 	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
1180 	Opt_auto_da_alloc, Opt_noauto_da_alloc, Opt_noload,
1181 	Opt_commit, Opt_min_batch_time, Opt_max_batch_time, Opt_journal_dev,
1182 	Opt_journal_path, Opt_journal_checksum, Opt_journal_async_commit,
1183 	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
1184 	Opt_data_err_abort, Opt_data_err_ignore, Opt_test_dummy_encryption,
1185 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
1186 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
1187 	Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err,
1188 	Opt_usrquota, Opt_grpquota, Opt_i_version, Opt_dax,
1189 	Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_mblk_io_submit,
1190 	Opt_lazytime, Opt_nolazytime,
1191 	Opt_nomblk_io_submit, Opt_block_validity, Opt_noblock_validity,
1192 	Opt_inode_readahead_blks, Opt_journal_ioprio,
1193 	Opt_dioread_nolock, Opt_dioread_lock,
1194 	Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
1195 	Opt_max_dir_size_kb, Opt_nojournal_checksum,
1196 };
1197 
1198 static const match_table_t tokens = {
1199 	{Opt_bsd_df, "bsddf"},
1200 	{Opt_minix_df, "minixdf"},
1201 	{Opt_grpid, "grpid"},
1202 	{Opt_grpid, "bsdgroups"},
1203 	{Opt_nogrpid, "nogrpid"},
1204 	{Opt_nogrpid, "sysvgroups"},
1205 	{Opt_resgid, "resgid=%u"},
1206 	{Opt_resuid, "resuid=%u"},
1207 	{Opt_sb, "sb=%u"},
1208 	{Opt_err_cont, "errors=continue"},
1209 	{Opt_err_panic, "errors=panic"},
1210 	{Opt_err_ro, "errors=remount-ro"},
1211 	{Opt_nouid32, "nouid32"},
1212 	{Opt_debug, "debug"},
1213 	{Opt_removed, "oldalloc"},
1214 	{Opt_removed, "orlov"},
1215 	{Opt_user_xattr, "user_xattr"},
1216 	{Opt_nouser_xattr, "nouser_xattr"},
1217 	{Opt_acl, "acl"},
1218 	{Opt_noacl, "noacl"},
1219 	{Opt_noload, "norecovery"},
1220 	{Opt_noload, "noload"},
1221 	{Opt_removed, "nobh"},
1222 	{Opt_removed, "bh"},
1223 	{Opt_commit, "commit=%u"},
1224 	{Opt_min_batch_time, "min_batch_time=%u"},
1225 	{Opt_max_batch_time, "max_batch_time=%u"},
1226 	{Opt_journal_dev, "journal_dev=%u"},
1227 	{Opt_journal_path, "journal_path=%s"},
1228 	{Opt_journal_checksum, "journal_checksum"},
1229 	{Opt_nojournal_checksum, "nojournal_checksum"},
1230 	{Opt_journal_async_commit, "journal_async_commit"},
1231 	{Opt_abort, "abort"},
1232 	{Opt_data_journal, "data=journal"},
1233 	{Opt_data_ordered, "data=ordered"},
1234 	{Opt_data_writeback, "data=writeback"},
1235 	{Opt_data_err_abort, "data_err=abort"},
1236 	{Opt_data_err_ignore, "data_err=ignore"},
1237 	{Opt_offusrjquota, "usrjquota="},
1238 	{Opt_usrjquota, "usrjquota=%s"},
1239 	{Opt_offgrpjquota, "grpjquota="},
1240 	{Opt_grpjquota, "grpjquota=%s"},
1241 	{Opt_jqfmt_vfsold, "jqfmt=vfsold"},
1242 	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
1243 	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
1244 	{Opt_grpquota, "grpquota"},
1245 	{Opt_noquota, "noquota"},
1246 	{Opt_quota, "quota"},
1247 	{Opt_usrquota, "usrquota"},
1248 	{Opt_barrier, "barrier=%u"},
1249 	{Opt_barrier, "barrier"},
1250 	{Opt_nobarrier, "nobarrier"},
1251 	{Opt_i_version, "i_version"},
1252 	{Opt_dax, "dax"},
1253 	{Opt_stripe, "stripe=%u"},
1254 	{Opt_delalloc, "delalloc"},
1255 	{Opt_lazytime, "lazytime"},
1256 	{Opt_nolazytime, "nolazytime"},
1257 	{Opt_nodelalloc, "nodelalloc"},
1258 	{Opt_removed, "mblk_io_submit"},
1259 	{Opt_removed, "nomblk_io_submit"},
1260 	{Opt_block_validity, "block_validity"},
1261 	{Opt_noblock_validity, "noblock_validity"},
1262 	{Opt_inode_readahead_blks, "inode_readahead_blks=%u"},
1263 	{Opt_journal_ioprio, "journal_ioprio=%u"},
1264 	{Opt_auto_da_alloc, "auto_da_alloc=%u"},
1265 	{Opt_auto_da_alloc, "auto_da_alloc"},
1266 	{Opt_noauto_da_alloc, "noauto_da_alloc"},
1267 	{Opt_dioread_nolock, "dioread_nolock"},
1268 	{Opt_dioread_lock, "dioread_lock"},
1269 	{Opt_discard, "discard"},
1270 	{Opt_nodiscard, "nodiscard"},
1271 	{Opt_init_itable, "init_itable=%u"},
1272 	{Opt_init_itable, "init_itable"},
1273 	{Opt_noinit_itable, "noinit_itable"},
1274 	{Opt_max_dir_size_kb, "max_dir_size_kb=%u"},
1275 	{Opt_test_dummy_encryption, "test_dummy_encryption"},
1276 	{Opt_removed, "check=none"},	/* mount option from ext2/3 */
1277 	{Opt_removed, "nocheck"},	/* mount option from ext2/3 */
1278 	{Opt_removed, "reservation"},	/* mount option from ext2/3 */
1279 	{Opt_removed, "noreservation"}, /* mount option from ext2/3 */
1280 	{Opt_removed, "journal=%u"},	/* mount option from ext2/3 */
1281 	{Opt_err, NULL},
1282 };
1283 
1284 static ext4_fsblk_t get_sb_block(void **data)
1285 {
1286 	ext4_fsblk_t	sb_block;
1287 	char		*options = (char *) *data;
1288 
1289 	if (!options || strncmp(options, "sb=", 3) != 0)
1290 		return 1;	/* Default location */
1291 
1292 	options += 3;
1293 	/* TODO: use simple_strtoll with >32bit ext4 */
1294 	sb_block = simple_strtoul(options, &options, 0);
1295 	if (*options && *options != ',') {
1296 		printk(KERN_ERR "EXT4-fs: Invalid sb specification: %s\n",
1297 		       (char *) *data);
1298 		return 1;
1299 	}
1300 	if (*options == ',')
1301 		options++;
1302 	*data = (void *) options;
1303 
1304 	return sb_block;
1305 }
1306 
1307 #define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))
1308 static char deprecated_msg[] = "Mount option \"%s\" will be removed by %s\n"
1309 	"Contact linux-ext4@vger.kernel.org if you think we should keep it.\n";
1310 
1311 #ifdef CONFIG_QUOTA
1312 static int set_qf_name(struct super_block *sb, int qtype, substring_t *args)
1313 {
1314 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1315 	char *qname;
1316 	int ret = -1;
1317 
1318 	if (sb_any_quota_loaded(sb) &&
1319 		!sbi->s_qf_names[qtype]) {
1320 		ext4_msg(sb, KERN_ERR,
1321 			"Cannot change journaled "
1322 			"quota options when quota turned on");
1323 		return -1;
1324 	}
1325 	if (ext4_has_feature_quota(sb)) {
1326 		ext4_msg(sb, KERN_ERR, "Cannot set journaled quota options "
1327 			 "when QUOTA feature is enabled");
1328 		return -1;
1329 	}
1330 	qname = match_strdup(args);
1331 	if (!qname) {
1332 		ext4_msg(sb, KERN_ERR,
1333 			"Not enough memory for storing quotafile name");
1334 		return -1;
1335 	}
1336 	if (sbi->s_qf_names[qtype]) {
1337 		if (strcmp(sbi->s_qf_names[qtype], qname) == 0)
1338 			ret = 1;
1339 		else
1340 			ext4_msg(sb, KERN_ERR,
1341 				 "%s quota file already specified",
1342 				 QTYPE2NAME(qtype));
1343 		goto errout;
1344 	}
1345 	if (strchr(qname, '/')) {
1346 		ext4_msg(sb, KERN_ERR,
1347 			"quotafile must be on filesystem root");
1348 		goto errout;
1349 	}
1350 	sbi->s_qf_names[qtype] = qname;
1351 	set_opt(sb, QUOTA);
1352 	return 1;
1353 errout:
1354 	kfree(qname);
1355 	return ret;
1356 }
1357 
1358 static int clear_qf_name(struct super_block *sb, int qtype)
1359 {
1360 
1361 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1362 
1363 	if (sb_any_quota_loaded(sb) &&
1364 		sbi->s_qf_names[qtype]) {
1365 		ext4_msg(sb, KERN_ERR, "Cannot change journaled quota options"
1366 			" when quota turned on");
1367 		return -1;
1368 	}
1369 	kfree(sbi->s_qf_names[qtype]);
1370 	sbi->s_qf_names[qtype] = NULL;
1371 	return 1;
1372 }
1373 #endif
1374 
1375 #define MOPT_SET	0x0001
1376 #define MOPT_CLEAR	0x0002
1377 #define MOPT_NOSUPPORT	0x0004
1378 #define MOPT_EXPLICIT	0x0008
1379 #define MOPT_CLEAR_ERR	0x0010
1380 #define MOPT_GTE0	0x0020
1381 #ifdef CONFIG_QUOTA
1382 #define MOPT_Q		0
1383 #define MOPT_QFMT	0x0040
1384 #else
1385 #define MOPT_Q		MOPT_NOSUPPORT
1386 #define MOPT_QFMT	MOPT_NOSUPPORT
1387 #endif
1388 #define MOPT_DATAJ	0x0080
1389 #define MOPT_NO_EXT2	0x0100
1390 #define MOPT_NO_EXT3	0x0200
1391 #define MOPT_EXT4_ONLY	(MOPT_NO_EXT2 | MOPT_NO_EXT3)
1392 #define MOPT_STRING	0x0400
1393 
1394 static const struct mount_opts {
1395 	int	token;
1396 	int	mount_opt;
1397 	int	flags;
1398 } ext4_mount_opts[] = {
1399 	{Opt_minix_df, EXT4_MOUNT_MINIX_DF, MOPT_SET},
1400 	{Opt_bsd_df, EXT4_MOUNT_MINIX_DF, MOPT_CLEAR},
1401 	{Opt_grpid, EXT4_MOUNT_GRPID, MOPT_SET},
1402 	{Opt_nogrpid, EXT4_MOUNT_GRPID, MOPT_CLEAR},
1403 	{Opt_block_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_SET},
1404 	{Opt_noblock_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_CLEAR},
1405 	{Opt_dioread_nolock, EXT4_MOUNT_DIOREAD_NOLOCK,
1406 	 MOPT_EXT4_ONLY | MOPT_SET},
1407 	{Opt_dioread_lock, EXT4_MOUNT_DIOREAD_NOLOCK,
1408 	 MOPT_EXT4_ONLY | MOPT_CLEAR},
1409 	{Opt_discard, EXT4_MOUNT_DISCARD, MOPT_SET},
1410 	{Opt_nodiscard, EXT4_MOUNT_DISCARD, MOPT_CLEAR},
1411 	{Opt_delalloc, EXT4_MOUNT_DELALLOC,
1412 	 MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
1413 	{Opt_nodelalloc, EXT4_MOUNT_DELALLOC,
1414 	 MOPT_EXT4_ONLY | MOPT_CLEAR},
1415 	{Opt_nojournal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,
1416 	 MOPT_EXT4_ONLY | MOPT_CLEAR},
1417 	{Opt_journal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,
1418 	 MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
1419 	{Opt_journal_async_commit, (EXT4_MOUNT_JOURNAL_ASYNC_COMMIT |
1420 				    EXT4_MOUNT_JOURNAL_CHECKSUM),
1421 	 MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
1422 	{Opt_noload, EXT4_MOUNT_NOLOAD, MOPT_NO_EXT2 | MOPT_SET},
1423 	{Opt_err_panic, EXT4_MOUNT_ERRORS_PANIC, MOPT_SET | MOPT_CLEAR_ERR},
1424 	{Opt_err_ro, EXT4_MOUNT_ERRORS_RO, MOPT_SET | MOPT_CLEAR_ERR},
1425 	{Opt_err_cont, EXT4_MOUNT_ERRORS_CONT, MOPT_SET | MOPT_CLEAR_ERR},
1426 	{Opt_data_err_abort, EXT4_MOUNT_DATA_ERR_ABORT,
1427 	 MOPT_NO_EXT2},
1428 	{Opt_data_err_ignore, EXT4_MOUNT_DATA_ERR_ABORT,
1429 	 MOPT_NO_EXT2},
1430 	{Opt_barrier, EXT4_MOUNT_BARRIER, MOPT_SET},
1431 	{Opt_nobarrier, EXT4_MOUNT_BARRIER, MOPT_CLEAR},
1432 	{Opt_noauto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_SET},
1433 	{Opt_auto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_CLEAR},
1434 	{Opt_noinit_itable, EXT4_MOUNT_INIT_INODE_TABLE, MOPT_CLEAR},
1435 	{Opt_commit, 0, MOPT_GTE0},
1436 	{Opt_max_batch_time, 0, MOPT_GTE0},
1437 	{Opt_min_batch_time, 0, MOPT_GTE0},
1438 	{Opt_inode_readahead_blks, 0, MOPT_GTE0},
1439 	{Opt_init_itable, 0, MOPT_GTE0},
1440 	{Opt_dax, EXT4_MOUNT_DAX, MOPT_SET},
1441 	{Opt_stripe, 0, MOPT_GTE0},
1442 	{Opt_resuid, 0, MOPT_GTE0},
1443 	{Opt_resgid, 0, MOPT_GTE0},
1444 	{Opt_journal_dev, 0, MOPT_NO_EXT2 | MOPT_GTE0},
1445 	{Opt_journal_path, 0, MOPT_NO_EXT2 | MOPT_STRING},
1446 	{Opt_journal_ioprio, 0, MOPT_NO_EXT2 | MOPT_GTE0},
1447 	{Opt_data_journal, EXT4_MOUNT_JOURNAL_DATA, MOPT_NO_EXT2 | MOPT_DATAJ},
1448 	{Opt_data_ordered, EXT4_MOUNT_ORDERED_DATA, MOPT_NO_EXT2 | MOPT_DATAJ},
1449 	{Opt_data_writeback, EXT4_MOUNT_WRITEBACK_DATA,
1450 	 MOPT_NO_EXT2 | MOPT_DATAJ},
1451 	{Opt_user_xattr, EXT4_MOUNT_XATTR_USER, MOPT_SET},
1452 	{Opt_nouser_xattr, EXT4_MOUNT_XATTR_USER, MOPT_CLEAR},
1453 #ifdef CONFIG_EXT4_FS_POSIX_ACL
1454 	{Opt_acl, EXT4_MOUNT_POSIX_ACL, MOPT_SET},
1455 	{Opt_noacl, EXT4_MOUNT_POSIX_ACL, MOPT_CLEAR},
1456 #else
1457 	{Opt_acl, 0, MOPT_NOSUPPORT},
1458 	{Opt_noacl, 0, MOPT_NOSUPPORT},
1459 #endif
1460 	{Opt_nouid32, EXT4_MOUNT_NO_UID32, MOPT_SET},
1461 	{Opt_debug, EXT4_MOUNT_DEBUG, MOPT_SET},
1462 	{Opt_quota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA, MOPT_SET | MOPT_Q},
1463 	{Opt_usrquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA,
1464 							MOPT_SET | MOPT_Q},
1465 	{Opt_grpquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_GRPQUOTA,
1466 							MOPT_SET | MOPT_Q},
1467 	{Opt_noquota, (EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA |
1468 		       EXT4_MOUNT_GRPQUOTA), MOPT_CLEAR | MOPT_Q},
1469 	{Opt_usrjquota, 0, MOPT_Q},
1470 	{Opt_grpjquota, 0, MOPT_Q},
1471 	{Opt_offusrjquota, 0, MOPT_Q},
1472 	{Opt_offgrpjquota, 0, MOPT_Q},
1473 	{Opt_jqfmt_vfsold, QFMT_VFS_OLD, MOPT_QFMT},
1474 	{Opt_jqfmt_vfsv0, QFMT_VFS_V0, MOPT_QFMT},
1475 	{Opt_jqfmt_vfsv1, QFMT_VFS_V1, MOPT_QFMT},
1476 	{Opt_max_dir_size_kb, 0, MOPT_GTE0},
1477 	{Opt_test_dummy_encryption, 0, MOPT_GTE0},
1478 	{Opt_err, 0, 0}
1479 };
1480 
1481 static int handle_mount_opt(struct super_block *sb, char *opt, int token,
1482 			    substring_t *args, unsigned long *journal_devnum,
1483 			    unsigned int *journal_ioprio, int is_remount)
1484 {
1485 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1486 	const struct mount_opts *m;
1487 	kuid_t uid;
1488 	kgid_t gid;
1489 	int arg = 0;
1490 
1491 #ifdef CONFIG_QUOTA
1492 	if (token == Opt_usrjquota)
1493 		return set_qf_name(sb, USRQUOTA, &args[0]);
1494 	else if (token == Opt_grpjquota)
1495 		return set_qf_name(sb, GRPQUOTA, &args[0]);
1496 	else if (token == Opt_offusrjquota)
1497 		return clear_qf_name(sb, USRQUOTA);
1498 	else if (token == Opt_offgrpjquota)
1499 		return clear_qf_name(sb, GRPQUOTA);
1500 #endif
1501 	switch (token) {
1502 	case Opt_noacl:
1503 	case Opt_nouser_xattr:
1504 		ext4_msg(sb, KERN_WARNING, deprecated_msg, opt, "3.5");
1505 		break;
1506 	case Opt_sb:
1507 		return 1;	/* handled by get_sb_block() */
1508 	case Opt_removed:
1509 		ext4_msg(sb, KERN_WARNING, "Ignoring removed %s option", opt);
1510 		return 1;
1511 	case Opt_abort:
1512 		sbi->s_mount_flags |= EXT4_MF_FS_ABORTED;
1513 		return 1;
1514 	case Opt_i_version:
1515 		sb->s_flags |= MS_I_VERSION;
1516 		return 1;
1517 	case Opt_lazytime:
1518 		sb->s_flags |= MS_LAZYTIME;
1519 		return 1;
1520 	case Opt_nolazytime:
1521 		sb->s_flags &= ~MS_LAZYTIME;
1522 		return 1;
1523 	}
1524 
1525 	for (m = ext4_mount_opts; m->token != Opt_err; m++)
1526 		if (token == m->token)
1527 			break;
1528 
1529 	if (m->token == Opt_err) {
1530 		ext4_msg(sb, KERN_ERR, "Unrecognized mount option \"%s\" "
1531 			 "or missing value", opt);
1532 		return -1;
1533 	}
1534 
1535 	if ((m->flags & MOPT_NO_EXT2) && IS_EXT2_SB(sb)) {
1536 		ext4_msg(sb, KERN_ERR,
1537 			 "Mount option \"%s\" incompatible with ext2", opt);
1538 		return -1;
1539 	}
1540 	if ((m->flags & MOPT_NO_EXT3) && IS_EXT3_SB(sb)) {
1541 		ext4_msg(sb, KERN_ERR,
1542 			 "Mount option \"%s\" incompatible with ext3", opt);
1543 		return -1;
1544 	}
1545 
1546 	if (args->from && !(m->flags & MOPT_STRING) && match_int(args, &arg))
1547 		return -1;
1548 	if (args->from && (m->flags & MOPT_GTE0) && (arg < 0))
1549 		return -1;
1550 	if (m->flags & MOPT_EXPLICIT) {
1551 		if (m->mount_opt & EXT4_MOUNT_DELALLOC) {
1552 			set_opt2(sb, EXPLICIT_DELALLOC);
1553 		} else if (m->mount_opt & EXT4_MOUNT_JOURNAL_CHECKSUM) {
1554 			set_opt2(sb, EXPLICIT_JOURNAL_CHECKSUM);
1555 		} else
1556 			return -1;
1557 	}
1558 	if (m->flags & MOPT_CLEAR_ERR)
1559 		clear_opt(sb, ERRORS_MASK);
1560 	if (token == Opt_noquota && sb_any_quota_loaded(sb)) {
1561 		ext4_msg(sb, KERN_ERR, "Cannot change quota "
1562 			 "options when quota turned on");
1563 		return -1;
1564 	}
1565 
1566 	if (m->flags & MOPT_NOSUPPORT) {
1567 		ext4_msg(sb, KERN_ERR, "%s option not supported", opt);
1568 	} else if (token == Opt_commit) {
1569 		if (arg == 0)
1570 			arg = JBD2_DEFAULT_MAX_COMMIT_AGE;
1571 		sbi->s_commit_interval = HZ * arg;
1572 	} else if (token == Opt_max_batch_time) {
1573 		sbi->s_max_batch_time = arg;
1574 	} else if (token == Opt_min_batch_time) {
1575 		sbi->s_min_batch_time = arg;
1576 	} else if (token == Opt_inode_readahead_blks) {
1577 		if (arg && (arg > (1 << 30) || !is_power_of_2(arg))) {
1578 			ext4_msg(sb, KERN_ERR,
1579 				 "EXT4-fs: inode_readahead_blks must be "
1580 				 "0 or a power of 2 smaller than 2^31");
1581 			return -1;
1582 		}
1583 		sbi->s_inode_readahead_blks = arg;
1584 	} else if (token == Opt_init_itable) {
1585 		set_opt(sb, INIT_INODE_TABLE);
1586 		if (!args->from)
1587 			arg = EXT4_DEF_LI_WAIT_MULT;
1588 		sbi->s_li_wait_mult = arg;
1589 	} else if (token == Opt_max_dir_size_kb) {
1590 		sbi->s_max_dir_size_kb = arg;
1591 	} else if (token == Opt_stripe) {
1592 		sbi->s_stripe = arg;
1593 	} else if (token == Opt_resuid) {
1594 		uid = make_kuid(current_user_ns(), arg);
1595 		if (!uid_valid(uid)) {
1596 			ext4_msg(sb, KERN_ERR, "Invalid uid value %d", arg);
1597 			return -1;
1598 		}
1599 		sbi->s_resuid = uid;
1600 	} else if (token == Opt_resgid) {
1601 		gid = make_kgid(current_user_ns(), arg);
1602 		if (!gid_valid(gid)) {
1603 			ext4_msg(sb, KERN_ERR, "Invalid gid value %d", arg);
1604 			return -1;
1605 		}
1606 		sbi->s_resgid = gid;
1607 	} else if (token == Opt_journal_dev) {
1608 		if (is_remount) {
1609 			ext4_msg(sb, KERN_ERR,
1610 				 "Cannot specify journal on remount");
1611 			return -1;
1612 		}
1613 		*journal_devnum = arg;
1614 	} else if (token == Opt_journal_path) {
1615 		char *journal_path;
1616 		struct inode *journal_inode;
1617 		struct path path;
1618 		int error;
1619 
1620 		if (is_remount) {
1621 			ext4_msg(sb, KERN_ERR,
1622 				 "Cannot specify journal on remount");
1623 			return -1;
1624 		}
1625 		journal_path = match_strdup(&args[0]);
1626 		if (!journal_path) {
1627 			ext4_msg(sb, KERN_ERR, "error: could not dup "
1628 				"journal device string");
1629 			return -1;
1630 		}
1631 
1632 		error = kern_path(journal_path, LOOKUP_FOLLOW, &path);
1633 		if (error) {
1634 			ext4_msg(sb, KERN_ERR, "error: could not find "
1635 				"journal device path: error %d", error);
1636 			kfree(journal_path);
1637 			return -1;
1638 		}
1639 
1640 		journal_inode = d_inode(path.dentry);
1641 		if (!S_ISBLK(journal_inode->i_mode)) {
1642 			ext4_msg(sb, KERN_ERR, "error: journal path %s "
1643 				"is not a block device", journal_path);
1644 			path_put(&path);
1645 			kfree(journal_path);
1646 			return -1;
1647 		}
1648 
1649 		*journal_devnum = new_encode_dev(journal_inode->i_rdev);
1650 		path_put(&path);
1651 		kfree(journal_path);
1652 	} else if (token == Opt_journal_ioprio) {
1653 		if (arg > 7) {
1654 			ext4_msg(sb, KERN_ERR, "Invalid journal IO priority"
1655 				 " (must be 0-7)");
1656 			return -1;
1657 		}
1658 		*journal_ioprio =
1659 			IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, arg);
1660 	} else if (token == Opt_test_dummy_encryption) {
1661 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1662 		sbi->s_mount_flags |= EXT4_MF_TEST_DUMMY_ENCRYPTION;
1663 		ext4_msg(sb, KERN_WARNING,
1664 			 "Test dummy encryption mode enabled");
1665 #else
1666 		ext4_msg(sb, KERN_WARNING,
1667 			 "Test dummy encryption mount option ignored");
1668 #endif
1669 	} else if (m->flags & MOPT_DATAJ) {
1670 		if (is_remount) {
1671 			if (!sbi->s_journal)
1672 				ext4_msg(sb, KERN_WARNING, "Remounting file system with no journal so ignoring journalled data option");
1673 			else if (test_opt(sb, DATA_FLAGS) != m->mount_opt) {
1674 				ext4_msg(sb, KERN_ERR,
1675 					 "Cannot change data mode on remount");
1676 				return -1;
1677 			}
1678 		} else {
1679 			clear_opt(sb, DATA_FLAGS);
1680 			sbi->s_mount_opt |= m->mount_opt;
1681 		}
1682 #ifdef CONFIG_QUOTA
1683 	} else if (m->flags & MOPT_QFMT) {
1684 		if (sb_any_quota_loaded(sb) &&
1685 		    sbi->s_jquota_fmt != m->mount_opt) {
1686 			ext4_msg(sb, KERN_ERR, "Cannot change journaled "
1687 				 "quota options when quota turned on");
1688 			return -1;
1689 		}
1690 		if (ext4_has_feature_quota(sb)) {
1691 			ext4_msg(sb, KERN_ERR,
1692 				 "Cannot set journaled quota options "
1693 				 "when QUOTA feature is enabled");
1694 			return -1;
1695 		}
1696 		sbi->s_jquota_fmt = m->mount_opt;
1697 #endif
1698 	} else if (token == Opt_dax) {
1699 #ifdef CONFIG_FS_DAX
1700 		ext4_msg(sb, KERN_WARNING,
1701 		"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
1702 			sbi->s_mount_opt |= m->mount_opt;
1703 #else
1704 		ext4_msg(sb, KERN_INFO, "dax option not supported");
1705 		return -1;
1706 #endif
1707 	} else if (token == Opt_data_err_abort) {
1708 		sbi->s_mount_opt |= m->mount_opt;
1709 	} else if (token == Opt_data_err_ignore) {
1710 		sbi->s_mount_opt &= ~m->mount_opt;
1711 	} else {
1712 		if (!args->from)
1713 			arg = 1;
1714 		if (m->flags & MOPT_CLEAR)
1715 			arg = !arg;
1716 		else if (unlikely(!(m->flags & MOPT_SET))) {
1717 			ext4_msg(sb, KERN_WARNING,
1718 				 "buggy handling of option %s", opt);
1719 			WARN_ON(1);
1720 			return -1;
1721 		}
1722 		if (arg != 0)
1723 			sbi->s_mount_opt |= m->mount_opt;
1724 		else
1725 			sbi->s_mount_opt &= ~m->mount_opt;
1726 	}
1727 	return 1;
1728 }
1729 
1730 static int parse_options(char *options, struct super_block *sb,
1731 			 unsigned long *journal_devnum,
1732 			 unsigned int *journal_ioprio,
1733 			 int is_remount)
1734 {
1735 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1736 	char *p;
1737 	substring_t args[MAX_OPT_ARGS];
1738 	int token;
1739 
1740 	if (!options)
1741 		return 1;
1742 
1743 	while ((p = strsep(&options, ",")) != NULL) {
1744 		if (!*p)
1745 			continue;
1746 		/*
1747 		 * Initialize args struct so we know whether arg was
1748 		 * found; some options take optional arguments.
1749 		 */
1750 		args[0].to = args[0].from = NULL;
1751 		token = match_token(p, tokens, args);
1752 		if (handle_mount_opt(sb, p, token, args, journal_devnum,
1753 				     journal_ioprio, is_remount) < 0)
1754 			return 0;
1755 	}
1756 #ifdef CONFIG_QUOTA
1757 	if (ext4_has_feature_quota(sb) &&
1758 	    (test_opt(sb, USRQUOTA) || test_opt(sb, GRPQUOTA))) {
1759 		ext4_msg(sb, KERN_ERR, "Cannot set quota options when QUOTA "
1760 			 "feature is enabled");
1761 		return 0;
1762 	}
1763 	if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
1764 		if (test_opt(sb, USRQUOTA) && sbi->s_qf_names[USRQUOTA])
1765 			clear_opt(sb, USRQUOTA);
1766 
1767 		if (test_opt(sb, GRPQUOTA) && sbi->s_qf_names[GRPQUOTA])
1768 			clear_opt(sb, GRPQUOTA);
1769 
1770 		if (test_opt(sb, GRPQUOTA) || test_opt(sb, USRQUOTA)) {
1771 			ext4_msg(sb, KERN_ERR, "old and new quota "
1772 					"format mixing");
1773 			return 0;
1774 		}
1775 
1776 		if (!sbi->s_jquota_fmt) {
1777 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1778 					"not specified");
1779 			return 0;
1780 		}
1781 	}
1782 #endif
1783 	if (test_opt(sb, DIOREAD_NOLOCK)) {
1784 		int blocksize =
1785 			BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
1786 
1787 		if (blocksize < PAGE_CACHE_SIZE) {
1788 			ext4_msg(sb, KERN_ERR, "can't mount with "
1789 				 "dioread_nolock if block size != PAGE_SIZE");
1790 			return 0;
1791 		}
1792 	}
1793 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA &&
1794 	    test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
1795 		ext4_msg(sb, KERN_ERR, "can't mount with journal_async_commit "
1796 			 "in data=ordered mode");
1797 		return 0;
1798 	}
1799 	return 1;
1800 }
1801 
1802 static inline void ext4_show_quota_options(struct seq_file *seq,
1803 					   struct super_block *sb)
1804 {
1805 #if defined(CONFIG_QUOTA)
1806 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1807 
1808 	if (sbi->s_jquota_fmt) {
1809 		char *fmtname = "";
1810 
1811 		switch (sbi->s_jquota_fmt) {
1812 		case QFMT_VFS_OLD:
1813 			fmtname = "vfsold";
1814 			break;
1815 		case QFMT_VFS_V0:
1816 			fmtname = "vfsv0";
1817 			break;
1818 		case QFMT_VFS_V1:
1819 			fmtname = "vfsv1";
1820 			break;
1821 		}
1822 		seq_printf(seq, ",jqfmt=%s", fmtname);
1823 	}
1824 
1825 	if (sbi->s_qf_names[USRQUOTA])
1826 		seq_show_option(seq, "usrjquota", sbi->s_qf_names[USRQUOTA]);
1827 
1828 	if (sbi->s_qf_names[GRPQUOTA])
1829 		seq_show_option(seq, "grpjquota", sbi->s_qf_names[GRPQUOTA]);
1830 #endif
1831 }
1832 
1833 static const char *token2str(int token)
1834 {
1835 	const struct match_token *t;
1836 
1837 	for (t = tokens; t->token != Opt_err; t++)
1838 		if (t->token == token && !strchr(t->pattern, '='))
1839 			break;
1840 	return t->pattern;
1841 }
1842 
1843 /*
1844  * Show an option if
1845  *  - it's set to a non-default value OR
1846  *  - if the per-sb default is different from the global default
1847  */
1848 static int _ext4_show_options(struct seq_file *seq, struct super_block *sb,
1849 			      int nodefs)
1850 {
1851 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1852 	struct ext4_super_block *es = sbi->s_es;
1853 	int def_errors, def_mount_opt = nodefs ? 0 : sbi->s_def_mount_opt;
1854 	const struct mount_opts *m;
1855 	char sep = nodefs ? '\n' : ',';
1856 
1857 #define SEQ_OPTS_PUTS(str) seq_printf(seq, "%c" str, sep)
1858 #define SEQ_OPTS_PRINT(str, arg) seq_printf(seq, "%c" str, sep, arg)
1859 
1860 	if (sbi->s_sb_block != 1)
1861 		SEQ_OPTS_PRINT("sb=%llu", sbi->s_sb_block);
1862 
1863 	for (m = ext4_mount_opts; m->token != Opt_err; m++) {
1864 		int want_set = m->flags & MOPT_SET;
1865 		if (((m->flags & (MOPT_SET|MOPT_CLEAR)) == 0) ||
1866 		    (m->flags & MOPT_CLEAR_ERR))
1867 			continue;
1868 		if (!(m->mount_opt & (sbi->s_mount_opt ^ def_mount_opt)))
1869 			continue; /* skip if same as the default */
1870 		if ((want_set &&
1871 		     (sbi->s_mount_opt & m->mount_opt) != m->mount_opt) ||
1872 		    (!want_set && (sbi->s_mount_opt & m->mount_opt)))
1873 			continue; /* select Opt_noFoo vs Opt_Foo */
1874 		SEQ_OPTS_PRINT("%s", token2str(m->token));
1875 	}
1876 
1877 	if (nodefs || !uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT4_DEF_RESUID)) ||
1878 	    le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID)
1879 		SEQ_OPTS_PRINT("resuid=%u",
1880 				from_kuid_munged(&init_user_ns, sbi->s_resuid));
1881 	if (nodefs || !gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT4_DEF_RESGID)) ||
1882 	    le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID)
1883 		SEQ_OPTS_PRINT("resgid=%u",
1884 				from_kgid_munged(&init_user_ns, sbi->s_resgid));
1885 	def_errors = nodefs ? -1 : le16_to_cpu(es->s_errors);
1886 	if (test_opt(sb, ERRORS_RO) && def_errors != EXT4_ERRORS_RO)
1887 		SEQ_OPTS_PUTS("errors=remount-ro");
1888 	if (test_opt(sb, ERRORS_CONT) && def_errors != EXT4_ERRORS_CONTINUE)
1889 		SEQ_OPTS_PUTS("errors=continue");
1890 	if (test_opt(sb, ERRORS_PANIC) && def_errors != EXT4_ERRORS_PANIC)
1891 		SEQ_OPTS_PUTS("errors=panic");
1892 	if (nodefs || sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ)
1893 		SEQ_OPTS_PRINT("commit=%lu", sbi->s_commit_interval / HZ);
1894 	if (nodefs || sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME)
1895 		SEQ_OPTS_PRINT("min_batch_time=%u", sbi->s_min_batch_time);
1896 	if (nodefs || sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME)
1897 		SEQ_OPTS_PRINT("max_batch_time=%u", sbi->s_max_batch_time);
1898 	if (sb->s_flags & MS_I_VERSION)
1899 		SEQ_OPTS_PUTS("i_version");
1900 	if (nodefs || sbi->s_stripe)
1901 		SEQ_OPTS_PRINT("stripe=%lu", sbi->s_stripe);
1902 	if (EXT4_MOUNT_DATA_FLAGS & (sbi->s_mount_opt ^ def_mount_opt)) {
1903 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
1904 			SEQ_OPTS_PUTS("data=journal");
1905 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
1906 			SEQ_OPTS_PUTS("data=ordered");
1907 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
1908 			SEQ_OPTS_PUTS("data=writeback");
1909 	}
1910 	if (nodefs ||
1911 	    sbi->s_inode_readahead_blks != EXT4_DEF_INODE_READAHEAD_BLKS)
1912 		SEQ_OPTS_PRINT("inode_readahead_blks=%u",
1913 			       sbi->s_inode_readahead_blks);
1914 
1915 	if (nodefs || (test_opt(sb, INIT_INODE_TABLE) &&
1916 		       (sbi->s_li_wait_mult != EXT4_DEF_LI_WAIT_MULT)))
1917 		SEQ_OPTS_PRINT("init_itable=%u", sbi->s_li_wait_mult);
1918 	if (nodefs || sbi->s_max_dir_size_kb)
1919 		SEQ_OPTS_PRINT("max_dir_size_kb=%u", sbi->s_max_dir_size_kb);
1920 	if (test_opt(sb, DATA_ERR_ABORT))
1921 		SEQ_OPTS_PUTS("data_err=abort");
1922 
1923 	ext4_show_quota_options(seq, sb);
1924 	return 0;
1925 }
1926 
1927 static int ext4_show_options(struct seq_file *seq, struct dentry *root)
1928 {
1929 	return _ext4_show_options(seq, root->d_sb, 0);
1930 }
1931 
1932 int ext4_seq_options_show(struct seq_file *seq, void *offset)
1933 {
1934 	struct super_block *sb = seq->private;
1935 	int rc;
1936 
1937 	seq_puts(seq, (sb->s_flags & MS_RDONLY) ? "ro" : "rw");
1938 	rc = _ext4_show_options(seq, sb, 1);
1939 	seq_puts(seq, "\n");
1940 	return rc;
1941 }
1942 
1943 static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
1944 			    int read_only)
1945 {
1946 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1947 	int res = 0;
1948 
1949 	if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
1950 		ext4_msg(sb, KERN_ERR, "revision level too high, "
1951 			 "forcing read-only mode");
1952 		res = MS_RDONLY;
1953 	}
1954 	if (read_only)
1955 		goto done;
1956 	if (!(sbi->s_mount_state & EXT4_VALID_FS))
1957 		ext4_msg(sb, KERN_WARNING, "warning: mounting unchecked fs, "
1958 			 "running e2fsck is recommended");
1959 	else if (sbi->s_mount_state & EXT4_ERROR_FS)
1960 		ext4_msg(sb, KERN_WARNING,
1961 			 "warning: mounting fs with errors, "
1962 			 "running e2fsck is recommended");
1963 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) > 0 &&
1964 		 le16_to_cpu(es->s_mnt_count) >=
1965 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
1966 		ext4_msg(sb, KERN_WARNING,
1967 			 "warning: maximal mount count reached, "
1968 			 "running e2fsck is recommended");
1969 	else if (le32_to_cpu(es->s_checkinterval) &&
1970 		(le32_to_cpu(es->s_lastcheck) +
1971 			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
1972 		ext4_msg(sb, KERN_WARNING,
1973 			 "warning: checktime reached, "
1974 			 "running e2fsck is recommended");
1975 	if (!sbi->s_journal)
1976 		es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1977 	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
1978 		es->s_max_mnt_count = cpu_to_le16(EXT4_DFL_MAX_MNT_COUNT);
1979 	le16_add_cpu(&es->s_mnt_count, 1);
1980 	es->s_mtime = cpu_to_le32(get_seconds());
1981 	ext4_update_dynamic_rev(sb);
1982 	if (sbi->s_journal)
1983 		ext4_set_feature_journal_needs_recovery(sb);
1984 
1985 	ext4_commit_super(sb, 1);
1986 done:
1987 	if (test_opt(sb, DEBUG))
1988 		printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, "
1989 				"bpg=%lu, ipg=%lu, mo=%04x, mo2=%04x]\n",
1990 			sb->s_blocksize,
1991 			sbi->s_groups_count,
1992 			EXT4_BLOCKS_PER_GROUP(sb),
1993 			EXT4_INODES_PER_GROUP(sb),
1994 			sbi->s_mount_opt, sbi->s_mount_opt2);
1995 
1996 	cleancache_init_fs(sb);
1997 	return res;
1998 }
1999 
2000 int ext4_alloc_flex_bg_array(struct super_block *sb, ext4_group_t ngroup)
2001 {
2002 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2003 	struct flex_groups *new_groups;
2004 	int size;
2005 
2006 	if (!sbi->s_log_groups_per_flex)
2007 		return 0;
2008 
2009 	size = ext4_flex_group(sbi, ngroup - 1) + 1;
2010 	if (size <= sbi->s_flex_groups_allocated)
2011 		return 0;
2012 
2013 	size = roundup_pow_of_two(size * sizeof(struct flex_groups));
2014 	new_groups = ext4_kvzalloc(size, GFP_KERNEL);
2015 	if (!new_groups) {
2016 		ext4_msg(sb, KERN_ERR, "not enough memory for %d flex groups",
2017 			 size / (int) sizeof(struct flex_groups));
2018 		return -ENOMEM;
2019 	}
2020 
2021 	if (sbi->s_flex_groups) {
2022 		memcpy(new_groups, sbi->s_flex_groups,
2023 		       (sbi->s_flex_groups_allocated *
2024 			sizeof(struct flex_groups)));
2025 		kvfree(sbi->s_flex_groups);
2026 	}
2027 	sbi->s_flex_groups = new_groups;
2028 	sbi->s_flex_groups_allocated = size / sizeof(struct flex_groups);
2029 	return 0;
2030 }
2031 
2032 static int ext4_fill_flex_info(struct super_block *sb)
2033 {
2034 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2035 	struct ext4_group_desc *gdp = NULL;
2036 	ext4_group_t flex_group;
2037 	int i, err;
2038 
2039 	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
2040 	if (sbi->s_log_groups_per_flex < 1 || sbi->s_log_groups_per_flex > 31) {
2041 		sbi->s_log_groups_per_flex = 0;
2042 		return 1;
2043 	}
2044 
2045 	err = ext4_alloc_flex_bg_array(sb, sbi->s_groups_count);
2046 	if (err)
2047 		goto failed;
2048 
2049 	for (i = 0; i < sbi->s_groups_count; i++) {
2050 		gdp = ext4_get_group_desc(sb, i, NULL);
2051 
2052 		flex_group = ext4_flex_group(sbi, i);
2053 		atomic_add(ext4_free_inodes_count(sb, gdp),
2054 			   &sbi->s_flex_groups[flex_group].free_inodes);
2055 		atomic64_add(ext4_free_group_clusters(sb, gdp),
2056 			     &sbi->s_flex_groups[flex_group].free_clusters);
2057 		atomic_add(ext4_used_dirs_count(sb, gdp),
2058 			   &sbi->s_flex_groups[flex_group].used_dirs);
2059 	}
2060 
2061 	return 1;
2062 failed:
2063 	return 0;
2064 }
2065 
2066 static __le16 ext4_group_desc_csum(struct super_block *sb, __u32 block_group,
2067 				   struct ext4_group_desc *gdp)
2068 {
2069 	int offset;
2070 	__u16 crc = 0;
2071 	__le32 le_group = cpu_to_le32(block_group);
2072 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2073 
2074 	if (ext4_has_metadata_csum(sbi->s_sb)) {
2075 		/* Use new metadata_csum algorithm */
2076 		__le16 save_csum;
2077 		__u32 csum32;
2078 
2079 		save_csum = gdp->bg_checksum;
2080 		gdp->bg_checksum = 0;
2081 		csum32 = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&le_group,
2082 				     sizeof(le_group));
2083 		csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp,
2084 				     sbi->s_desc_size);
2085 		gdp->bg_checksum = save_csum;
2086 
2087 		crc = csum32 & 0xFFFF;
2088 		goto out;
2089 	}
2090 
2091 	/* old crc16 code */
2092 	if (!ext4_has_feature_gdt_csum(sb))
2093 		return 0;
2094 
2095 	offset = offsetof(struct ext4_group_desc, bg_checksum);
2096 
2097 	crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
2098 	crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
2099 	crc = crc16(crc, (__u8 *)gdp, offset);
2100 	offset += sizeof(gdp->bg_checksum); /* skip checksum */
2101 	/* for checksum of struct ext4_group_desc do the rest...*/
2102 	if (ext4_has_feature_64bit(sb) &&
2103 	    offset < le16_to_cpu(sbi->s_es->s_desc_size))
2104 		crc = crc16(crc, (__u8 *)gdp + offset,
2105 			    le16_to_cpu(sbi->s_es->s_desc_size) -
2106 				offset);
2107 
2108 out:
2109 	return cpu_to_le16(crc);
2110 }
2111 
2112 int ext4_group_desc_csum_verify(struct super_block *sb, __u32 block_group,
2113 				struct ext4_group_desc *gdp)
2114 {
2115 	if (ext4_has_group_desc_csum(sb) &&
2116 	    (gdp->bg_checksum != ext4_group_desc_csum(sb, block_group, gdp)))
2117 		return 0;
2118 
2119 	return 1;
2120 }
2121 
2122 void ext4_group_desc_csum_set(struct super_block *sb, __u32 block_group,
2123 			      struct ext4_group_desc *gdp)
2124 {
2125 	if (!ext4_has_group_desc_csum(sb))
2126 		return;
2127 	gdp->bg_checksum = ext4_group_desc_csum(sb, block_group, gdp);
2128 }
2129 
2130 /* Called at mount-time, super-block is locked */
2131 static int ext4_check_descriptors(struct super_block *sb,
2132 				  ext4_group_t *first_not_zeroed)
2133 {
2134 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2135 	ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
2136 	ext4_fsblk_t last_block;
2137 	ext4_fsblk_t block_bitmap;
2138 	ext4_fsblk_t inode_bitmap;
2139 	ext4_fsblk_t inode_table;
2140 	int flexbg_flag = 0;
2141 	ext4_group_t i, grp = sbi->s_groups_count;
2142 
2143 	if (ext4_has_feature_flex_bg(sb))
2144 		flexbg_flag = 1;
2145 
2146 	ext4_debug("Checking group descriptors");
2147 
2148 	for (i = 0; i < sbi->s_groups_count; i++) {
2149 		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
2150 
2151 		if (i == sbi->s_groups_count - 1 || flexbg_flag)
2152 			last_block = ext4_blocks_count(sbi->s_es) - 1;
2153 		else
2154 			last_block = first_block +
2155 				(EXT4_BLOCKS_PER_GROUP(sb) - 1);
2156 
2157 		if ((grp == sbi->s_groups_count) &&
2158 		   !(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2159 			grp = i;
2160 
2161 		block_bitmap = ext4_block_bitmap(sb, gdp);
2162 		if (block_bitmap < first_block || block_bitmap > last_block) {
2163 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2164 			       "Block bitmap for group %u not in group "
2165 			       "(block %llu)!", i, block_bitmap);
2166 			return 0;
2167 		}
2168 		inode_bitmap = ext4_inode_bitmap(sb, gdp);
2169 		if (inode_bitmap < first_block || inode_bitmap > last_block) {
2170 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2171 			       "Inode bitmap for group %u not in group "
2172 			       "(block %llu)!", i, inode_bitmap);
2173 			return 0;
2174 		}
2175 		inode_table = ext4_inode_table(sb, gdp);
2176 		if (inode_table < first_block ||
2177 		    inode_table + sbi->s_itb_per_group - 1 > last_block) {
2178 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2179 			       "Inode table for group %u not in group "
2180 			       "(block %llu)!", i, inode_table);
2181 			return 0;
2182 		}
2183 		ext4_lock_group(sb, i);
2184 		if (!ext4_group_desc_csum_verify(sb, i, gdp)) {
2185 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2186 				 "Checksum for group %u failed (%u!=%u)",
2187 				 i, le16_to_cpu(ext4_group_desc_csum(sb, i,
2188 				     gdp)), le16_to_cpu(gdp->bg_checksum));
2189 			if (!(sb->s_flags & MS_RDONLY)) {
2190 				ext4_unlock_group(sb, i);
2191 				return 0;
2192 			}
2193 		}
2194 		ext4_unlock_group(sb, i);
2195 		if (!flexbg_flag)
2196 			first_block += EXT4_BLOCKS_PER_GROUP(sb);
2197 	}
2198 	if (NULL != first_not_zeroed)
2199 		*first_not_zeroed = grp;
2200 	return 1;
2201 }
2202 
2203 /* ext4_orphan_cleanup() walks a singly-linked list of inodes (starting at
2204  * the superblock) which were deleted from all directories, but held open by
2205  * a process at the time of a crash.  We walk the list and try to delete these
2206  * inodes at recovery time (only with a read-write filesystem).
2207  *
2208  * In order to keep the orphan inode chain consistent during traversal (in
2209  * case of crash during recovery), we link each inode into the superblock
2210  * orphan list_head and handle it the same way as an inode deletion during
2211  * normal operation (which journals the operations for us).
2212  *
2213  * We only do an iget() and an iput() on each inode, which is very safe if we
2214  * accidentally point at an in-use or already deleted inode.  The worst that
2215  * can happen in this case is that we get a "bit already cleared" message from
2216  * ext4_free_inode().  The only reason we would point at a wrong inode is if
2217  * e2fsck was run on this filesystem, and it must have already done the orphan
2218  * inode cleanup for us, so we can safely abort without any further action.
2219  */
2220 static void ext4_orphan_cleanup(struct super_block *sb,
2221 				struct ext4_super_block *es)
2222 {
2223 	unsigned int s_flags = sb->s_flags;
2224 	int nr_orphans = 0, nr_truncates = 0;
2225 #ifdef CONFIG_QUOTA
2226 	int i;
2227 #endif
2228 	if (!es->s_last_orphan) {
2229 		jbd_debug(4, "no orphan inodes to clean up\n");
2230 		return;
2231 	}
2232 
2233 	if (bdev_read_only(sb->s_bdev)) {
2234 		ext4_msg(sb, KERN_ERR, "write access "
2235 			"unavailable, skipping orphan cleanup");
2236 		return;
2237 	}
2238 
2239 	/* Check if feature set would not allow a r/w mount */
2240 	if (!ext4_feature_set_ok(sb, 0)) {
2241 		ext4_msg(sb, KERN_INFO, "Skipping orphan cleanup due to "
2242 			 "unknown ROCOMPAT features");
2243 		return;
2244 	}
2245 
2246 	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
2247 		/* don't clear list on RO mount w/ errors */
2248 		if (es->s_last_orphan && !(s_flags & MS_RDONLY)) {
2249 			ext4_msg(sb, KERN_INFO, "Errors on filesystem, "
2250 				  "clearing orphan list.\n");
2251 			es->s_last_orphan = 0;
2252 		}
2253 		jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
2254 		return;
2255 	}
2256 
2257 	if (s_flags & MS_RDONLY) {
2258 		ext4_msg(sb, KERN_INFO, "orphan cleanup on readonly fs");
2259 		sb->s_flags &= ~MS_RDONLY;
2260 	}
2261 #ifdef CONFIG_QUOTA
2262 	/* Needed for iput() to work correctly and not trash data */
2263 	sb->s_flags |= MS_ACTIVE;
2264 	/* Turn on quotas so that they are updated correctly */
2265 	for (i = 0; i < EXT4_MAXQUOTAS; i++) {
2266 		if (EXT4_SB(sb)->s_qf_names[i]) {
2267 			int ret = ext4_quota_on_mount(sb, i);
2268 			if (ret < 0)
2269 				ext4_msg(sb, KERN_ERR,
2270 					"Cannot turn on journaled "
2271 					"quota: error %d", ret);
2272 		}
2273 	}
2274 #endif
2275 
2276 	while (es->s_last_orphan) {
2277 		struct inode *inode;
2278 
2279 		inode = ext4_orphan_get(sb, le32_to_cpu(es->s_last_orphan));
2280 		if (IS_ERR(inode)) {
2281 			es->s_last_orphan = 0;
2282 			break;
2283 		}
2284 
2285 		list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
2286 		dquot_initialize(inode);
2287 		if (inode->i_nlink) {
2288 			if (test_opt(sb, DEBUG))
2289 				ext4_msg(sb, KERN_DEBUG,
2290 					"%s: truncating inode %lu to %lld bytes",
2291 					__func__, inode->i_ino, inode->i_size);
2292 			jbd_debug(2, "truncating inode %lu to %lld bytes\n",
2293 				  inode->i_ino, inode->i_size);
2294 			inode_lock(inode);
2295 			truncate_inode_pages(inode->i_mapping, inode->i_size);
2296 			ext4_truncate(inode);
2297 			inode_unlock(inode);
2298 			nr_truncates++;
2299 		} else {
2300 			if (test_opt(sb, DEBUG))
2301 				ext4_msg(sb, KERN_DEBUG,
2302 					"%s: deleting unreferenced inode %lu",
2303 					__func__, inode->i_ino);
2304 			jbd_debug(2, "deleting unreferenced inode %lu\n",
2305 				  inode->i_ino);
2306 			nr_orphans++;
2307 		}
2308 		iput(inode);  /* The delete magic happens here! */
2309 	}
2310 
2311 #define PLURAL(x) (x), ((x) == 1) ? "" : "s"
2312 
2313 	if (nr_orphans)
2314 		ext4_msg(sb, KERN_INFO, "%d orphan inode%s deleted",
2315 		       PLURAL(nr_orphans));
2316 	if (nr_truncates)
2317 		ext4_msg(sb, KERN_INFO, "%d truncate%s cleaned up",
2318 		       PLURAL(nr_truncates));
2319 #ifdef CONFIG_QUOTA
2320 	/* Turn quotas off */
2321 	for (i = 0; i < EXT4_MAXQUOTAS; i++) {
2322 		if (sb_dqopt(sb)->files[i])
2323 			dquot_quota_off(sb, i);
2324 	}
2325 #endif
2326 	sb->s_flags = s_flags; /* Restore MS_RDONLY status */
2327 }
2328 
2329 /*
2330  * Maximal extent format file size.
2331  * Resulting logical blkno at s_maxbytes must fit in our on-disk
2332  * extent format containers, within a sector_t, and within i_blocks
2333  * in the vfs.  ext4 inode has 48 bits of i_block in fsblock units,
2334  * so that won't be a limiting factor.
2335  *
2336  * However there is other limiting factor. We do store extents in the form
2337  * of starting block and length, hence the resulting length of the extent
2338  * covering maximum file size must fit into on-disk format containers as
2339  * well. Given that length is always by 1 unit bigger than max unit (because
2340  * we count 0 as well) we have to lower the s_maxbytes by one fs block.
2341  *
2342  * Note, this does *not* consider any metadata overhead for vfs i_blocks.
2343  */
2344 static loff_t ext4_max_size(int blkbits, int has_huge_files)
2345 {
2346 	loff_t res;
2347 	loff_t upper_limit = MAX_LFS_FILESIZE;
2348 
2349 	/* small i_blocks in vfs inode? */
2350 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2351 		/*
2352 		 * CONFIG_LBDAF is not enabled implies the inode
2353 		 * i_block represent total blocks in 512 bytes
2354 		 * 32 == size of vfs inode i_blocks * 8
2355 		 */
2356 		upper_limit = (1LL << 32) - 1;
2357 
2358 		/* total blocks in file system block size */
2359 		upper_limit >>= (blkbits - 9);
2360 		upper_limit <<= blkbits;
2361 	}
2362 
2363 	/*
2364 	 * 32-bit extent-start container, ee_block. We lower the maxbytes
2365 	 * by one fs block, so ee_len can cover the extent of maximum file
2366 	 * size
2367 	 */
2368 	res = (1LL << 32) - 1;
2369 	res <<= blkbits;
2370 
2371 	/* Sanity check against vm- & vfs- imposed limits */
2372 	if (res > upper_limit)
2373 		res = upper_limit;
2374 
2375 	return res;
2376 }
2377 
2378 /*
2379  * Maximal bitmap file size.  There is a direct, and {,double-,triple-}indirect
2380  * block limit, and also a limit of (2^48 - 1) 512-byte sectors in i_blocks.
2381  * We need to be 1 filesystem block less than the 2^48 sector limit.
2382  */
2383 static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
2384 {
2385 	loff_t res = EXT4_NDIR_BLOCKS;
2386 	int meta_blocks;
2387 	loff_t upper_limit;
2388 	/* This is calculated to be the largest file size for a dense, block
2389 	 * mapped file such that the file's total number of 512-byte sectors,
2390 	 * including data and all indirect blocks, does not exceed (2^48 - 1).
2391 	 *
2392 	 * __u32 i_blocks_lo and _u16 i_blocks_high represent the total
2393 	 * number of 512-byte sectors of the file.
2394 	 */
2395 
2396 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2397 		/*
2398 		 * !has_huge_files or CONFIG_LBDAF not enabled implies that
2399 		 * the inode i_block field represents total file blocks in
2400 		 * 2^32 512-byte sectors == size of vfs inode i_blocks * 8
2401 		 */
2402 		upper_limit = (1LL << 32) - 1;
2403 
2404 		/* total blocks in file system block size */
2405 		upper_limit >>= (bits - 9);
2406 
2407 	} else {
2408 		/*
2409 		 * We use 48 bit ext4_inode i_blocks
2410 		 * With EXT4_HUGE_FILE_FL set the i_blocks
2411 		 * represent total number of blocks in
2412 		 * file system block size
2413 		 */
2414 		upper_limit = (1LL << 48) - 1;
2415 
2416 	}
2417 
2418 	/* indirect blocks */
2419 	meta_blocks = 1;
2420 	/* double indirect blocks */
2421 	meta_blocks += 1 + (1LL << (bits-2));
2422 	/* tripple indirect blocks */
2423 	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
2424 
2425 	upper_limit -= meta_blocks;
2426 	upper_limit <<= bits;
2427 
2428 	res += 1LL << (bits-2);
2429 	res += 1LL << (2*(bits-2));
2430 	res += 1LL << (3*(bits-2));
2431 	res <<= bits;
2432 	if (res > upper_limit)
2433 		res = upper_limit;
2434 
2435 	if (res > MAX_LFS_FILESIZE)
2436 		res = MAX_LFS_FILESIZE;
2437 
2438 	return res;
2439 }
2440 
2441 static ext4_fsblk_t descriptor_loc(struct super_block *sb,
2442 				   ext4_fsblk_t logical_sb_block, int nr)
2443 {
2444 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2445 	ext4_group_t bg, first_meta_bg;
2446 	int has_super = 0;
2447 
2448 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
2449 
2450 	if (!ext4_has_feature_meta_bg(sb) || nr < first_meta_bg)
2451 		return logical_sb_block + nr + 1;
2452 	bg = sbi->s_desc_per_block * nr;
2453 	if (ext4_bg_has_super(sb, bg))
2454 		has_super = 1;
2455 
2456 	/*
2457 	 * If we have a meta_bg fs with 1k blocks, group 0's GDT is at
2458 	 * block 2, not 1.  If s_first_data_block == 0 (bigalloc is enabled
2459 	 * on modern mke2fs or blksize > 1k on older mke2fs) then we must
2460 	 * compensate.
2461 	 */
2462 	if (sb->s_blocksize == 1024 && nr == 0 &&
2463 	    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block) == 0)
2464 		has_super++;
2465 
2466 	return (has_super + ext4_group_first_block_no(sb, bg));
2467 }
2468 
2469 /**
2470  * ext4_get_stripe_size: Get the stripe size.
2471  * @sbi: In memory super block info
2472  *
2473  * If we have specified it via mount option, then
2474  * use the mount option value. If the value specified at mount time is
2475  * greater than the blocks per group use the super block value.
2476  * If the super block value is greater than blocks per group return 0.
2477  * Allocator needs it be less than blocks per group.
2478  *
2479  */
2480 static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi)
2481 {
2482 	unsigned long stride = le16_to_cpu(sbi->s_es->s_raid_stride);
2483 	unsigned long stripe_width =
2484 			le32_to_cpu(sbi->s_es->s_raid_stripe_width);
2485 	int ret;
2486 
2487 	if (sbi->s_stripe && sbi->s_stripe <= sbi->s_blocks_per_group)
2488 		ret = sbi->s_stripe;
2489 	else if (stripe_width <= sbi->s_blocks_per_group)
2490 		ret = stripe_width;
2491 	else if (stride <= sbi->s_blocks_per_group)
2492 		ret = stride;
2493 	else
2494 		ret = 0;
2495 
2496 	/*
2497 	 * If the stripe width is 1, this makes no sense and
2498 	 * we set it to 0 to turn off stripe handling code.
2499 	 */
2500 	if (ret <= 1)
2501 		ret = 0;
2502 
2503 	return ret;
2504 }
2505 
2506 /*
2507  * Check whether this filesystem can be mounted based on
2508  * the features present and the RDONLY/RDWR mount requested.
2509  * Returns 1 if this filesystem can be mounted as requested,
2510  * 0 if it cannot be.
2511  */
2512 static int ext4_feature_set_ok(struct super_block *sb, int readonly)
2513 {
2514 	if (ext4_has_unknown_ext4_incompat_features(sb)) {
2515 		ext4_msg(sb, KERN_ERR,
2516 			"Couldn't mount because of "
2517 			"unsupported optional features (%x)",
2518 			(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_incompat) &
2519 			~EXT4_FEATURE_INCOMPAT_SUPP));
2520 		return 0;
2521 	}
2522 
2523 	if (readonly)
2524 		return 1;
2525 
2526 	if (ext4_has_feature_readonly(sb)) {
2527 		ext4_msg(sb, KERN_INFO, "filesystem is read-only");
2528 		sb->s_flags |= MS_RDONLY;
2529 		return 1;
2530 	}
2531 
2532 	/* Check that feature set is OK for a read-write mount */
2533 	if (ext4_has_unknown_ext4_ro_compat_features(sb)) {
2534 		ext4_msg(sb, KERN_ERR, "couldn't mount RDWR because of "
2535 			 "unsupported optional features (%x)",
2536 			 (le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_ro_compat) &
2537 				~EXT4_FEATURE_RO_COMPAT_SUPP));
2538 		return 0;
2539 	}
2540 	/*
2541 	 * Large file size enabled file system can only be mounted
2542 	 * read-write on 32-bit systems if kernel is built with CONFIG_LBDAF
2543 	 */
2544 	if (ext4_has_feature_huge_file(sb)) {
2545 		if (sizeof(blkcnt_t) < sizeof(u64)) {
2546 			ext4_msg(sb, KERN_ERR, "Filesystem with huge files "
2547 				 "cannot be mounted RDWR without "
2548 				 "CONFIG_LBDAF");
2549 			return 0;
2550 		}
2551 	}
2552 	if (ext4_has_feature_bigalloc(sb) && !ext4_has_feature_extents(sb)) {
2553 		ext4_msg(sb, KERN_ERR,
2554 			 "Can't support bigalloc feature without "
2555 			 "extents feature\n");
2556 		return 0;
2557 	}
2558 
2559 #ifndef CONFIG_QUOTA
2560 	if (ext4_has_feature_quota(sb) && !readonly) {
2561 		ext4_msg(sb, KERN_ERR,
2562 			 "Filesystem with quota feature cannot be mounted RDWR "
2563 			 "without CONFIG_QUOTA");
2564 		return 0;
2565 	}
2566 	if (ext4_has_feature_project(sb) && !readonly) {
2567 		ext4_msg(sb, KERN_ERR,
2568 			 "Filesystem with project quota feature cannot be mounted RDWR "
2569 			 "without CONFIG_QUOTA");
2570 		return 0;
2571 	}
2572 #endif  /* CONFIG_QUOTA */
2573 	return 1;
2574 }
2575 
2576 /*
2577  * This function is called once a day if we have errors logged
2578  * on the file system
2579  */
2580 static void print_daily_error_info(unsigned long arg)
2581 {
2582 	struct super_block *sb = (struct super_block *) arg;
2583 	struct ext4_sb_info *sbi;
2584 	struct ext4_super_block *es;
2585 
2586 	sbi = EXT4_SB(sb);
2587 	es = sbi->s_es;
2588 
2589 	if (es->s_error_count)
2590 		/* fsck newer than v1.41.13 is needed to clean this condition. */
2591 		ext4_msg(sb, KERN_NOTICE, "error count since last fsck: %u",
2592 			 le32_to_cpu(es->s_error_count));
2593 	if (es->s_first_error_time) {
2594 		printk(KERN_NOTICE "EXT4-fs (%s): initial error at time %u: %.*s:%d",
2595 		       sb->s_id, le32_to_cpu(es->s_first_error_time),
2596 		       (int) sizeof(es->s_first_error_func),
2597 		       es->s_first_error_func,
2598 		       le32_to_cpu(es->s_first_error_line));
2599 		if (es->s_first_error_ino)
2600 			printk(": inode %u",
2601 			       le32_to_cpu(es->s_first_error_ino));
2602 		if (es->s_first_error_block)
2603 			printk(": block %llu", (unsigned long long)
2604 			       le64_to_cpu(es->s_first_error_block));
2605 		printk("\n");
2606 	}
2607 	if (es->s_last_error_time) {
2608 		printk(KERN_NOTICE "EXT4-fs (%s): last error at time %u: %.*s:%d",
2609 		       sb->s_id, le32_to_cpu(es->s_last_error_time),
2610 		       (int) sizeof(es->s_last_error_func),
2611 		       es->s_last_error_func,
2612 		       le32_to_cpu(es->s_last_error_line));
2613 		if (es->s_last_error_ino)
2614 			printk(": inode %u",
2615 			       le32_to_cpu(es->s_last_error_ino));
2616 		if (es->s_last_error_block)
2617 			printk(": block %llu", (unsigned long long)
2618 			       le64_to_cpu(es->s_last_error_block));
2619 		printk("\n");
2620 	}
2621 	mod_timer(&sbi->s_err_report, jiffies + 24*60*60*HZ);  /* Once a day */
2622 }
2623 
2624 /* Find next suitable group and run ext4_init_inode_table */
2625 static int ext4_run_li_request(struct ext4_li_request *elr)
2626 {
2627 	struct ext4_group_desc *gdp = NULL;
2628 	ext4_group_t group, ngroups;
2629 	struct super_block *sb;
2630 	unsigned long timeout = 0;
2631 	int ret = 0;
2632 
2633 	sb = elr->lr_super;
2634 	ngroups = EXT4_SB(sb)->s_groups_count;
2635 
2636 	sb_start_write(sb);
2637 	for (group = elr->lr_next_group; group < ngroups; group++) {
2638 		gdp = ext4_get_group_desc(sb, group, NULL);
2639 		if (!gdp) {
2640 			ret = 1;
2641 			break;
2642 		}
2643 
2644 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2645 			break;
2646 	}
2647 
2648 	if (group >= ngroups)
2649 		ret = 1;
2650 
2651 	if (!ret) {
2652 		timeout = jiffies;
2653 		ret = ext4_init_inode_table(sb, group,
2654 					    elr->lr_timeout ? 0 : 1);
2655 		if (elr->lr_timeout == 0) {
2656 			timeout = (jiffies - timeout) *
2657 				  elr->lr_sbi->s_li_wait_mult;
2658 			elr->lr_timeout = timeout;
2659 		}
2660 		elr->lr_next_sched = jiffies + elr->lr_timeout;
2661 		elr->lr_next_group = group + 1;
2662 	}
2663 	sb_end_write(sb);
2664 
2665 	return ret;
2666 }
2667 
2668 /*
2669  * Remove lr_request from the list_request and free the
2670  * request structure. Should be called with li_list_mtx held
2671  */
2672 static void ext4_remove_li_request(struct ext4_li_request *elr)
2673 {
2674 	struct ext4_sb_info *sbi;
2675 
2676 	if (!elr)
2677 		return;
2678 
2679 	sbi = elr->lr_sbi;
2680 
2681 	list_del(&elr->lr_request);
2682 	sbi->s_li_request = NULL;
2683 	kfree(elr);
2684 }
2685 
2686 static void ext4_unregister_li_request(struct super_block *sb)
2687 {
2688 	mutex_lock(&ext4_li_mtx);
2689 	if (!ext4_li_info) {
2690 		mutex_unlock(&ext4_li_mtx);
2691 		return;
2692 	}
2693 
2694 	mutex_lock(&ext4_li_info->li_list_mtx);
2695 	ext4_remove_li_request(EXT4_SB(sb)->s_li_request);
2696 	mutex_unlock(&ext4_li_info->li_list_mtx);
2697 	mutex_unlock(&ext4_li_mtx);
2698 }
2699 
2700 static struct task_struct *ext4_lazyinit_task;
2701 
2702 /*
2703  * This is the function where ext4lazyinit thread lives. It walks
2704  * through the request list searching for next scheduled filesystem.
2705  * When such a fs is found, run the lazy initialization request
2706  * (ext4_rn_li_request) and keep track of the time spend in this
2707  * function. Based on that time we compute next schedule time of
2708  * the request. When walking through the list is complete, compute
2709  * next waking time and put itself into sleep.
2710  */
2711 static int ext4_lazyinit_thread(void *arg)
2712 {
2713 	struct ext4_lazy_init *eli = (struct ext4_lazy_init *)arg;
2714 	struct list_head *pos, *n;
2715 	struct ext4_li_request *elr;
2716 	unsigned long next_wakeup, cur;
2717 
2718 	BUG_ON(NULL == eli);
2719 
2720 cont_thread:
2721 	while (true) {
2722 		next_wakeup = MAX_JIFFY_OFFSET;
2723 
2724 		mutex_lock(&eli->li_list_mtx);
2725 		if (list_empty(&eli->li_request_list)) {
2726 			mutex_unlock(&eli->li_list_mtx);
2727 			goto exit_thread;
2728 		}
2729 
2730 		list_for_each_safe(pos, n, &eli->li_request_list) {
2731 			elr = list_entry(pos, struct ext4_li_request,
2732 					 lr_request);
2733 
2734 			if (time_after_eq(jiffies, elr->lr_next_sched)) {
2735 				if (ext4_run_li_request(elr) != 0) {
2736 					/* error, remove the lazy_init job */
2737 					ext4_remove_li_request(elr);
2738 					continue;
2739 				}
2740 			}
2741 
2742 			if (time_before(elr->lr_next_sched, next_wakeup))
2743 				next_wakeup = elr->lr_next_sched;
2744 		}
2745 		mutex_unlock(&eli->li_list_mtx);
2746 
2747 		try_to_freeze();
2748 
2749 		cur = jiffies;
2750 		if ((time_after_eq(cur, next_wakeup)) ||
2751 		    (MAX_JIFFY_OFFSET == next_wakeup)) {
2752 			cond_resched();
2753 			continue;
2754 		}
2755 
2756 		schedule_timeout_interruptible(next_wakeup - cur);
2757 
2758 		if (kthread_should_stop()) {
2759 			ext4_clear_request_list();
2760 			goto exit_thread;
2761 		}
2762 	}
2763 
2764 exit_thread:
2765 	/*
2766 	 * It looks like the request list is empty, but we need
2767 	 * to check it under the li_list_mtx lock, to prevent any
2768 	 * additions into it, and of course we should lock ext4_li_mtx
2769 	 * to atomically free the list and ext4_li_info, because at
2770 	 * this point another ext4 filesystem could be registering
2771 	 * new one.
2772 	 */
2773 	mutex_lock(&ext4_li_mtx);
2774 	mutex_lock(&eli->li_list_mtx);
2775 	if (!list_empty(&eli->li_request_list)) {
2776 		mutex_unlock(&eli->li_list_mtx);
2777 		mutex_unlock(&ext4_li_mtx);
2778 		goto cont_thread;
2779 	}
2780 	mutex_unlock(&eli->li_list_mtx);
2781 	kfree(ext4_li_info);
2782 	ext4_li_info = NULL;
2783 	mutex_unlock(&ext4_li_mtx);
2784 
2785 	return 0;
2786 }
2787 
2788 static void ext4_clear_request_list(void)
2789 {
2790 	struct list_head *pos, *n;
2791 	struct ext4_li_request *elr;
2792 
2793 	mutex_lock(&ext4_li_info->li_list_mtx);
2794 	list_for_each_safe(pos, n, &ext4_li_info->li_request_list) {
2795 		elr = list_entry(pos, struct ext4_li_request,
2796 				 lr_request);
2797 		ext4_remove_li_request(elr);
2798 	}
2799 	mutex_unlock(&ext4_li_info->li_list_mtx);
2800 }
2801 
2802 static int ext4_run_lazyinit_thread(void)
2803 {
2804 	ext4_lazyinit_task = kthread_run(ext4_lazyinit_thread,
2805 					 ext4_li_info, "ext4lazyinit");
2806 	if (IS_ERR(ext4_lazyinit_task)) {
2807 		int err = PTR_ERR(ext4_lazyinit_task);
2808 		ext4_clear_request_list();
2809 		kfree(ext4_li_info);
2810 		ext4_li_info = NULL;
2811 		printk(KERN_CRIT "EXT4-fs: error %d creating inode table "
2812 				 "initialization thread\n",
2813 				 err);
2814 		return err;
2815 	}
2816 	ext4_li_info->li_state |= EXT4_LAZYINIT_RUNNING;
2817 	return 0;
2818 }
2819 
2820 /*
2821  * Check whether it make sense to run itable init. thread or not.
2822  * If there is at least one uninitialized inode table, return
2823  * corresponding group number, else the loop goes through all
2824  * groups and return total number of groups.
2825  */
2826 static ext4_group_t ext4_has_uninit_itable(struct super_block *sb)
2827 {
2828 	ext4_group_t group, ngroups = EXT4_SB(sb)->s_groups_count;
2829 	struct ext4_group_desc *gdp = NULL;
2830 
2831 	for (group = 0; group < ngroups; group++) {
2832 		gdp = ext4_get_group_desc(sb, group, NULL);
2833 		if (!gdp)
2834 			continue;
2835 
2836 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2837 			break;
2838 	}
2839 
2840 	return group;
2841 }
2842 
2843 static int ext4_li_info_new(void)
2844 {
2845 	struct ext4_lazy_init *eli = NULL;
2846 
2847 	eli = kzalloc(sizeof(*eli), GFP_KERNEL);
2848 	if (!eli)
2849 		return -ENOMEM;
2850 
2851 	INIT_LIST_HEAD(&eli->li_request_list);
2852 	mutex_init(&eli->li_list_mtx);
2853 
2854 	eli->li_state |= EXT4_LAZYINIT_QUIT;
2855 
2856 	ext4_li_info = eli;
2857 
2858 	return 0;
2859 }
2860 
2861 static struct ext4_li_request *ext4_li_request_new(struct super_block *sb,
2862 					    ext4_group_t start)
2863 {
2864 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2865 	struct ext4_li_request *elr;
2866 
2867 	elr = kzalloc(sizeof(*elr), GFP_KERNEL);
2868 	if (!elr)
2869 		return NULL;
2870 
2871 	elr->lr_super = sb;
2872 	elr->lr_sbi = sbi;
2873 	elr->lr_next_group = start;
2874 
2875 	/*
2876 	 * Randomize first schedule time of the request to
2877 	 * spread the inode table initialization requests
2878 	 * better.
2879 	 */
2880 	elr->lr_next_sched = jiffies + (prandom_u32() %
2881 				(EXT4_DEF_LI_MAX_START_DELAY * HZ));
2882 	return elr;
2883 }
2884 
2885 int ext4_register_li_request(struct super_block *sb,
2886 			     ext4_group_t first_not_zeroed)
2887 {
2888 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2889 	struct ext4_li_request *elr = NULL;
2890 	ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
2891 	int ret = 0;
2892 
2893 	mutex_lock(&ext4_li_mtx);
2894 	if (sbi->s_li_request != NULL) {
2895 		/*
2896 		 * Reset timeout so it can be computed again, because
2897 		 * s_li_wait_mult might have changed.
2898 		 */
2899 		sbi->s_li_request->lr_timeout = 0;
2900 		goto out;
2901 	}
2902 
2903 	if (first_not_zeroed == ngroups ||
2904 	    (sb->s_flags & MS_RDONLY) ||
2905 	    !test_opt(sb, INIT_INODE_TABLE))
2906 		goto out;
2907 
2908 	elr = ext4_li_request_new(sb, first_not_zeroed);
2909 	if (!elr) {
2910 		ret = -ENOMEM;
2911 		goto out;
2912 	}
2913 
2914 	if (NULL == ext4_li_info) {
2915 		ret = ext4_li_info_new();
2916 		if (ret)
2917 			goto out;
2918 	}
2919 
2920 	mutex_lock(&ext4_li_info->li_list_mtx);
2921 	list_add(&elr->lr_request, &ext4_li_info->li_request_list);
2922 	mutex_unlock(&ext4_li_info->li_list_mtx);
2923 
2924 	sbi->s_li_request = elr;
2925 	/*
2926 	 * set elr to NULL here since it has been inserted to
2927 	 * the request_list and the removal and free of it is
2928 	 * handled by ext4_clear_request_list from now on.
2929 	 */
2930 	elr = NULL;
2931 
2932 	if (!(ext4_li_info->li_state & EXT4_LAZYINIT_RUNNING)) {
2933 		ret = ext4_run_lazyinit_thread();
2934 		if (ret)
2935 			goto out;
2936 	}
2937 out:
2938 	mutex_unlock(&ext4_li_mtx);
2939 	if (ret)
2940 		kfree(elr);
2941 	return ret;
2942 }
2943 
2944 /*
2945  * We do not need to lock anything since this is called on
2946  * module unload.
2947  */
2948 static void ext4_destroy_lazyinit_thread(void)
2949 {
2950 	/*
2951 	 * If thread exited earlier
2952 	 * there's nothing to be done.
2953 	 */
2954 	if (!ext4_li_info || !ext4_lazyinit_task)
2955 		return;
2956 
2957 	kthread_stop(ext4_lazyinit_task);
2958 }
2959 
2960 static int set_journal_csum_feature_set(struct super_block *sb)
2961 {
2962 	int ret = 1;
2963 	int compat, incompat;
2964 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2965 
2966 	if (ext4_has_metadata_csum(sb)) {
2967 		/* journal checksum v3 */
2968 		compat = 0;
2969 		incompat = JBD2_FEATURE_INCOMPAT_CSUM_V3;
2970 	} else {
2971 		/* journal checksum v1 */
2972 		compat = JBD2_FEATURE_COMPAT_CHECKSUM;
2973 		incompat = 0;
2974 	}
2975 
2976 	jbd2_journal_clear_features(sbi->s_journal,
2977 			JBD2_FEATURE_COMPAT_CHECKSUM, 0,
2978 			JBD2_FEATURE_INCOMPAT_CSUM_V3 |
2979 			JBD2_FEATURE_INCOMPAT_CSUM_V2);
2980 	if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
2981 		ret = jbd2_journal_set_features(sbi->s_journal,
2982 				compat, 0,
2983 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT |
2984 				incompat);
2985 	} else if (test_opt(sb, JOURNAL_CHECKSUM)) {
2986 		ret = jbd2_journal_set_features(sbi->s_journal,
2987 				compat, 0,
2988 				incompat);
2989 		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
2990 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
2991 	} else {
2992 		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
2993 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
2994 	}
2995 
2996 	return ret;
2997 }
2998 
2999 /*
3000  * Note: calculating the overhead so we can be compatible with
3001  * historical BSD practice is quite difficult in the face of
3002  * clusters/bigalloc.  This is because multiple metadata blocks from
3003  * different block group can end up in the same allocation cluster.
3004  * Calculating the exact overhead in the face of clustered allocation
3005  * requires either O(all block bitmaps) in memory or O(number of block
3006  * groups**2) in time.  We will still calculate the superblock for
3007  * older file systems --- and if we come across with a bigalloc file
3008  * system with zero in s_overhead_clusters the estimate will be close to
3009  * correct especially for very large cluster sizes --- but for newer
3010  * file systems, it's better to calculate this figure once at mkfs
3011  * time, and store it in the superblock.  If the superblock value is
3012  * present (even for non-bigalloc file systems), we will use it.
3013  */
3014 static int count_overhead(struct super_block *sb, ext4_group_t grp,
3015 			  char *buf)
3016 {
3017 	struct ext4_sb_info	*sbi = EXT4_SB(sb);
3018 	struct ext4_group_desc	*gdp;
3019 	ext4_fsblk_t		first_block, last_block, b;
3020 	ext4_group_t		i, ngroups = ext4_get_groups_count(sb);
3021 	int			s, j, count = 0;
3022 
3023 	if (!ext4_has_feature_bigalloc(sb))
3024 		return (ext4_bg_has_super(sb, grp) + ext4_bg_num_gdb(sb, grp) +
3025 			sbi->s_itb_per_group + 2);
3026 
3027 	first_block = le32_to_cpu(sbi->s_es->s_first_data_block) +
3028 		(grp * EXT4_BLOCKS_PER_GROUP(sb));
3029 	last_block = first_block + EXT4_BLOCKS_PER_GROUP(sb) - 1;
3030 	for (i = 0; i < ngroups; i++) {
3031 		gdp = ext4_get_group_desc(sb, i, NULL);
3032 		b = ext4_block_bitmap(sb, gdp);
3033 		if (b >= first_block && b <= last_block) {
3034 			ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf);
3035 			count++;
3036 		}
3037 		b = ext4_inode_bitmap(sb, gdp);
3038 		if (b >= first_block && b <= last_block) {
3039 			ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf);
3040 			count++;
3041 		}
3042 		b = ext4_inode_table(sb, gdp);
3043 		if (b >= first_block && b + sbi->s_itb_per_group <= last_block)
3044 			for (j = 0; j < sbi->s_itb_per_group; j++, b++) {
3045 				int c = EXT4_B2C(sbi, b - first_block);
3046 				ext4_set_bit(c, buf);
3047 				count++;
3048 			}
3049 		if (i != grp)
3050 			continue;
3051 		s = 0;
3052 		if (ext4_bg_has_super(sb, grp)) {
3053 			ext4_set_bit(s++, buf);
3054 			count++;
3055 		}
3056 		for (j = ext4_bg_num_gdb(sb, grp); j > 0; j--) {
3057 			ext4_set_bit(EXT4_B2C(sbi, s++), buf);
3058 			count++;
3059 		}
3060 	}
3061 	if (!count)
3062 		return 0;
3063 	return EXT4_CLUSTERS_PER_GROUP(sb) -
3064 		ext4_count_free(buf, EXT4_CLUSTERS_PER_GROUP(sb) / 8);
3065 }
3066 
3067 /*
3068  * Compute the overhead and stash it in sbi->s_overhead
3069  */
3070 int ext4_calculate_overhead(struct super_block *sb)
3071 {
3072 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3073 	struct ext4_super_block *es = sbi->s_es;
3074 	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
3075 	ext4_fsblk_t overhead = 0;
3076 	char *buf = (char *) get_zeroed_page(GFP_NOFS);
3077 
3078 	if (!buf)
3079 		return -ENOMEM;
3080 
3081 	/*
3082 	 * Compute the overhead (FS structures).  This is constant
3083 	 * for a given filesystem unless the number of block groups
3084 	 * changes so we cache the previous value until it does.
3085 	 */
3086 
3087 	/*
3088 	 * All of the blocks before first_data_block are overhead
3089 	 */
3090 	overhead = EXT4_B2C(sbi, le32_to_cpu(es->s_first_data_block));
3091 
3092 	/*
3093 	 * Add the overhead found in each block group
3094 	 */
3095 	for (i = 0; i < ngroups; i++) {
3096 		int blks;
3097 
3098 		blks = count_overhead(sb, i, buf);
3099 		overhead += blks;
3100 		if (blks)
3101 			memset(buf, 0, PAGE_SIZE);
3102 		cond_resched();
3103 	}
3104 	/* Add the internal journal blocks as well */
3105 	if (sbi->s_journal && !sbi->journal_bdev)
3106 		overhead += EXT4_NUM_B2C(sbi, sbi->s_journal->j_maxlen);
3107 
3108 	sbi->s_overhead = overhead;
3109 	smp_wmb();
3110 	free_page((unsigned long) buf);
3111 	return 0;
3112 }
3113 
3114 static void ext4_set_resv_clusters(struct super_block *sb)
3115 {
3116 	ext4_fsblk_t resv_clusters;
3117 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3118 
3119 	/*
3120 	 * There's no need to reserve anything when we aren't using extents.
3121 	 * The space estimates are exact, there are no unwritten extents,
3122 	 * hole punching doesn't need new metadata... This is needed especially
3123 	 * to keep ext2/3 backward compatibility.
3124 	 */
3125 	if (!ext4_has_feature_extents(sb))
3126 		return;
3127 	/*
3128 	 * By default we reserve 2% or 4096 clusters, whichever is smaller.
3129 	 * This should cover the situations where we can not afford to run
3130 	 * out of space like for example punch hole, or converting
3131 	 * unwritten extents in delalloc path. In most cases such
3132 	 * allocation would require 1, or 2 blocks, higher numbers are
3133 	 * very rare.
3134 	 */
3135 	resv_clusters = (ext4_blocks_count(sbi->s_es) >>
3136 			 sbi->s_cluster_bits);
3137 
3138 	do_div(resv_clusters, 50);
3139 	resv_clusters = min_t(ext4_fsblk_t, resv_clusters, 4096);
3140 
3141 	atomic64_set(&sbi->s_resv_clusters, resv_clusters);
3142 }
3143 
3144 static int ext4_fill_super(struct super_block *sb, void *data, int silent)
3145 {
3146 	char *orig_data = kstrdup(data, GFP_KERNEL);
3147 	struct buffer_head *bh;
3148 	struct ext4_super_block *es = NULL;
3149 	struct ext4_sb_info *sbi;
3150 	ext4_fsblk_t block;
3151 	ext4_fsblk_t sb_block = get_sb_block(&data);
3152 	ext4_fsblk_t logical_sb_block;
3153 	unsigned long offset = 0;
3154 	unsigned long journal_devnum = 0;
3155 	unsigned long def_mount_opts;
3156 	struct inode *root;
3157 	const char *descr;
3158 	int ret = -ENOMEM;
3159 	int blocksize, clustersize;
3160 	unsigned int db_count;
3161 	unsigned int i;
3162 	int needs_recovery, has_huge_files, has_bigalloc;
3163 	__u64 blocks_count;
3164 	int err = 0;
3165 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
3166 	ext4_group_t first_not_zeroed;
3167 
3168 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
3169 	if (!sbi)
3170 		goto out_free_orig;
3171 
3172 	sbi->s_blockgroup_lock =
3173 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
3174 	if (!sbi->s_blockgroup_lock) {
3175 		kfree(sbi);
3176 		goto out_free_orig;
3177 	}
3178 	sb->s_fs_info = sbi;
3179 	sbi->s_sb = sb;
3180 	sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
3181 	sbi->s_sb_block = sb_block;
3182 	if (sb->s_bdev->bd_part)
3183 		sbi->s_sectors_written_start =
3184 			part_stat_read(sb->s_bdev->bd_part, sectors[1]);
3185 
3186 	/* Cleanup superblock name */
3187 	strreplace(sb->s_id, '/', '!');
3188 
3189 	/* -EINVAL is default */
3190 	ret = -EINVAL;
3191 	blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
3192 	if (!blocksize) {
3193 		ext4_msg(sb, KERN_ERR, "unable to set blocksize");
3194 		goto out_fail;
3195 	}
3196 
3197 	/*
3198 	 * The ext4 superblock will not be buffer aligned for other than 1kB
3199 	 * block sizes.  We need to calculate the offset from buffer start.
3200 	 */
3201 	if (blocksize != EXT4_MIN_BLOCK_SIZE) {
3202 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3203 		offset = do_div(logical_sb_block, blocksize);
3204 	} else {
3205 		logical_sb_block = sb_block;
3206 	}
3207 
3208 	if (!(bh = sb_bread_unmovable(sb, logical_sb_block))) {
3209 		ext4_msg(sb, KERN_ERR, "unable to read superblock");
3210 		goto out_fail;
3211 	}
3212 	/*
3213 	 * Note: s_es must be initialized as soon as possible because
3214 	 *       some ext4 macro-instructions depend on its value
3215 	 */
3216 	es = (struct ext4_super_block *) (bh->b_data + offset);
3217 	sbi->s_es = es;
3218 	sb->s_magic = le16_to_cpu(es->s_magic);
3219 	if (sb->s_magic != EXT4_SUPER_MAGIC)
3220 		goto cantfind_ext4;
3221 	sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
3222 
3223 	/* Warn if metadata_csum and gdt_csum are both set. */
3224 	if (ext4_has_feature_metadata_csum(sb) &&
3225 	    ext4_has_feature_gdt_csum(sb))
3226 		ext4_warning(sb, "metadata_csum and uninit_bg are "
3227 			     "redundant flags; please run fsck.");
3228 
3229 	/* Check for a known checksum algorithm */
3230 	if (!ext4_verify_csum_type(sb, es)) {
3231 		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
3232 			 "unknown checksum algorithm.");
3233 		silent = 1;
3234 		goto cantfind_ext4;
3235 	}
3236 
3237 	/* Load the checksum driver */
3238 	if (ext4_has_feature_metadata_csum(sb)) {
3239 		sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
3240 		if (IS_ERR(sbi->s_chksum_driver)) {
3241 			ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
3242 			ret = PTR_ERR(sbi->s_chksum_driver);
3243 			sbi->s_chksum_driver = NULL;
3244 			goto failed_mount;
3245 		}
3246 	}
3247 
3248 	/* Check superblock checksum */
3249 	if (!ext4_superblock_csum_verify(sb, es)) {
3250 		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
3251 			 "invalid superblock checksum.  Run e2fsck?");
3252 		silent = 1;
3253 		ret = -EFSBADCRC;
3254 		goto cantfind_ext4;
3255 	}
3256 
3257 	/* Precompute checksum seed for all metadata */
3258 	if (ext4_has_feature_csum_seed(sb))
3259 		sbi->s_csum_seed = le32_to_cpu(es->s_checksum_seed);
3260 	else if (ext4_has_metadata_csum(sb))
3261 		sbi->s_csum_seed = ext4_chksum(sbi, ~0, es->s_uuid,
3262 					       sizeof(es->s_uuid));
3263 
3264 	/* Set defaults before we parse the mount options */
3265 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
3266 	set_opt(sb, INIT_INODE_TABLE);
3267 	if (def_mount_opts & EXT4_DEFM_DEBUG)
3268 		set_opt(sb, DEBUG);
3269 	if (def_mount_opts & EXT4_DEFM_BSDGROUPS)
3270 		set_opt(sb, GRPID);
3271 	if (def_mount_opts & EXT4_DEFM_UID16)
3272 		set_opt(sb, NO_UID32);
3273 	/* xattr user namespace & acls are now defaulted on */
3274 	set_opt(sb, XATTR_USER);
3275 #ifdef CONFIG_EXT4_FS_POSIX_ACL
3276 	set_opt(sb, POSIX_ACL);
3277 #endif
3278 	/* don't forget to enable journal_csum when metadata_csum is enabled. */
3279 	if (ext4_has_metadata_csum(sb))
3280 		set_opt(sb, JOURNAL_CHECKSUM);
3281 
3282 	if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA)
3283 		set_opt(sb, JOURNAL_DATA);
3284 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_ORDERED)
3285 		set_opt(sb, ORDERED_DATA);
3286 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_WBACK)
3287 		set_opt(sb, WRITEBACK_DATA);
3288 
3289 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_PANIC)
3290 		set_opt(sb, ERRORS_PANIC);
3291 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_CONTINUE)
3292 		set_opt(sb, ERRORS_CONT);
3293 	else
3294 		set_opt(sb, ERRORS_RO);
3295 	/* block_validity enabled by default; disable with noblock_validity */
3296 	set_opt(sb, BLOCK_VALIDITY);
3297 	if (def_mount_opts & EXT4_DEFM_DISCARD)
3298 		set_opt(sb, DISCARD);
3299 
3300 	sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
3301 	sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
3302 	sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ;
3303 	sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;
3304 	sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;
3305 
3306 	if ((def_mount_opts & EXT4_DEFM_NOBARRIER) == 0)
3307 		set_opt(sb, BARRIER);
3308 
3309 	/*
3310 	 * enable delayed allocation by default
3311 	 * Use -o nodelalloc to turn it off
3312 	 */
3313 	if (!IS_EXT3_SB(sb) && !IS_EXT2_SB(sb) &&
3314 	    ((def_mount_opts & EXT4_DEFM_NODELALLOC) == 0))
3315 		set_opt(sb, DELALLOC);
3316 
3317 	/*
3318 	 * set default s_li_wait_mult for lazyinit, for the case there is
3319 	 * no mount option specified.
3320 	 */
3321 	sbi->s_li_wait_mult = EXT4_DEF_LI_WAIT_MULT;
3322 
3323 	if (!parse_options((char *) sbi->s_es->s_mount_opts, sb,
3324 			   &journal_devnum, &journal_ioprio, 0)) {
3325 		ext4_msg(sb, KERN_WARNING,
3326 			 "failed to parse options in superblock: %s",
3327 			 sbi->s_es->s_mount_opts);
3328 	}
3329 	sbi->s_def_mount_opt = sbi->s_mount_opt;
3330 	if (!parse_options((char *) data, sb, &journal_devnum,
3331 			   &journal_ioprio, 0))
3332 		goto failed_mount;
3333 
3334 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
3335 		printk_once(KERN_WARNING "EXT4-fs: Warning: mounting "
3336 			    "with data=journal disables delayed "
3337 			    "allocation and O_DIRECT support!\n");
3338 		if (test_opt2(sb, EXPLICIT_DELALLOC)) {
3339 			ext4_msg(sb, KERN_ERR, "can't mount with "
3340 				 "both data=journal and delalloc");
3341 			goto failed_mount;
3342 		}
3343 		if (test_opt(sb, DIOREAD_NOLOCK)) {
3344 			ext4_msg(sb, KERN_ERR, "can't mount with "
3345 				 "both data=journal and dioread_nolock");
3346 			goto failed_mount;
3347 		}
3348 		if (test_opt(sb, DAX)) {
3349 			ext4_msg(sb, KERN_ERR, "can't mount with "
3350 				 "both data=journal and dax");
3351 			goto failed_mount;
3352 		}
3353 		if (test_opt(sb, DELALLOC))
3354 			clear_opt(sb, DELALLOC);
3355 	} else {
3356 		sb->s_iflags |= SB_I_CGROUPWB;
3357 	}
3358 
3359 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
3360 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
3361 
3362 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
3363 	    (ext4_has_compat_features(sb) ||
3364 	     ext4_has_ro_compat_features(sb) ||
3365 	     ext4_has_incompat_features(sb)))
3366 		ext4_msg(sb, KERN_WARNING,
3367 		       "feature flags set on rev 0 fs, "
3368 		       "running e2fsck is recommended");
3369 
3370 	if (es->s_creator_os == cpu_to_le32(EXT4_OS_HURD)) {
3371 		set_opt2(sb, HURD_COMPAT);
3372 		if (ext4_has_feature_64bit(sb)) {
3373 			ext4_msg(sb, KERN_ERR,
3374 				 "The Hurd can't support 64-bit file systems");
3375 			goto failed_mount;
3376 		}
3377 	}
3378 
3379 	if (IS_EXT2_SB(sb)) {
3380 		if (ext2_feature_set_ok(sb))
3381 			ext4_msg(sb, KERN_INFO, "mounting ext2 file system "
3382 				 "using the ext4 subsystem");
3383 		else {
3384 			ext4_msg(sb, KERN_ERR, "couldn't mount as ext2 due "
3385 				 "to feature incompatibilities");
3386 			goto failed_mount;
3387 		}
3388 	}
3389 
3390 	if (IS_EXT3_SB(sb)) {
3391 		if (ext3_feature_set_ok(sb))
3392 			ext4_msg(sb, KERN_INFO, "mounting ext3 file system "
3393 				 "using the ext4 subsystem");
3394 		else {
3395 			ext4_msg(sb, KERN_ERR, "couldn't mount as ext3 due "
3396 				 "to feature incompatibilities");
3397 			goto failed_mount;
3398 		}
3399 	}
3400 
3401 	/*
3402 	 * Check feature flags regardless of the revision level, since we
3403 	 * previously didn't change the revision level when setting the flags,
3404 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
3405 	 */
3406 	if (!ext4_feature_set_ok(sb, (sb->s_flags & MS_RDONLY)))
3407 		goto failed_mount;
3408 
3409 	blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
3410 	if (blocksize < EXT4_MIN_BLOCK_SIZE ||
3411 	    blocksize > EXT4_MAX_BLOCK_SIZE) {
3412 		ext4_msg(sb, KERN_ERR,
3413 		       "Unsupported filesystem blocksize %d", blocksize);
3414 		goto failed_mount;
3415 	}
3416 
3417 	if (sbi->s_mount_opt & EXT4_MOUNT_DAX) {
3418 		if (blocksize != PAGE_SIZE) {
3419 			ext4_msg(sb, KERN_ERR,
3420 					"error: unsupported blocksize for dax");
3421 			goto failed_mount;
3422 		}
3423 		if (!sb->s_bdev->bd_disk->fops->direct_access) {
3424 			ext4_msg(sb, KERN_ERR,
3425 					"error: device does not support dax");
3426 			goto failed_mount;
3427 		}
3428 	}
3429 
3430 	if (ext4_has_feature_encrypt(sb) && es->s_encryption_level) {
3431 		ext4_msg(sb, KERN_ERR, "Unsupported encryption level %d",
3432 			 es->s_encryption_level);
3433 		goto failed_mount;
3434 	}
3435 
3436 	if (sb->s_blocksize != blocksize) {
3437 		/* Validate the filesystem blocksize */
3438 		if (!sb_set_blocksize(sb, blocksize)) {
3439 			ext4_msg(sb, KERN_ERR, "bad block size %d",
3440 					blocksize);
3441 			goto failed_mount;
3442 		}
3443 
3444 		brelse(bh);
3445 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3446 		offset = do_div(logical_sb_block, blocksize);
3447 		bh = sb_bread_unmovable(sb, logical_sb_block);
3448 		if (!bh) {
3449 			ext4_msg(sb, KERN_ERR,
3450 			       "Can't read superblock on 2nd try");
3451 			goto failed_mount;
3452 		}
3453 		es = (struct ext4_super_block *)(bh->b_data + offset);
3454 		sbi->s_es = es;
3455 		if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
3456 			ext4_msg(sb, KERN_ERR,
3457 			       "Magic mismatch, very weird!");
3458 			goto failed_mount;
3459 		}
3460 	}
3461 
3462 	has_huge_files = ext4_has_feature_huge_file(sb);
3463 	sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits,
3464 						      has_huge_files);
3465 	sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits, has_huge_files);
3466 
3467 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) {
3468 		sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE;
3469 		sbi->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
3470 	} else {
3471 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
3472 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
3473 		if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
3474 		    (!is_power_of_2(sbi->s_inode_size)) ||
3475 		    (sbi->s_inode_size > blocksize)) {
3476 			ext4_msg(sb, KERN_ERR,
3477 			       "unsupported inode size: %d",
3478 			       sbi->s_inode_size);
3479 			goto failed_mount;
3480 		}
3481 		if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE)
3482 			sb->s_time_gran = 1 << (EXT4_EPOCH_BITS - 2);
3483 	}
3484 
3485 	sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
3486 	if (ext4_has_feature_64bit(sb)) {
3487 		if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT ||
3488 		    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
3489 		    !is_power_of_2(sbi->s_desc_size)) {
3490 			ext4_msg(sb, KERN_ERR,
3491 			       "unsupported descriptor size %lu",
3492 			       sbi->s_desc_size);
3493 			goto failed_mount;
3494 		}
3495 	} else
3496 		sbi->s_desc_size = EXT4_MIN_DESC_SIZE;
3497 
3498 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
3499 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
3500 	if (EXT4_INODE_SIZE(sb) == 0 || EXT4_INODES_PER_GROUP(sb) == 0)
3501 		goto cantfind_ext4;
3502 
3503 	sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
3504 	if (sbi->s_inodes_per_block == 0)
3505 		goto cantfind_ext4;
3506 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
3507 					sbi->s_inodes_per_block;
3508 	sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
3509 	sbi->s_sbh = bh;
3510 	sbi->s_mount_state = le16_to_cpu(es->s_state);
3511 	sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
3512 	sbi->s_desc_per_block_bits = ilog2(EXT4_DESC_PER_BLOCK(sb));
3513 
3514 	for (i = 0; i < 4; i++)
3515 		sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
3516 	sbi->s_def_hash_version = es->s_def_hash_version;
3517 	if (ext4_has_feature_dir_index(sb)) {
3518 		i = le32_to_cpu(es->s_flags);
3519 		if (i & EXT2_FLAGS_UNSIGNED_HASH)
3520 			sbi->s_hash_unsigned = 3;
3521 		else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) {
3522 #ifdef __CHAR_UNSIGNED__
3523 			if (!(sb->s_flags & MS_RDONLY))
3524 				es->s_flags |=
3525 					cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH);
3526 			sbi->s_hash_unsigned = 3;
3527 #else
3528 			if (!(sb->s_flags & MS_RDONLY))
3529 				es->s_flags |=
3530 					cpu_to_le32(EXT2_FLAGS_SIGNED_HASH);
3531 #endif
3532 		}
3533 	}
3534 
3535 	/* Handle clustersize */
3536 	clustersize = BLOCK_SIZE << le32_to_cpu(es->s_log_cluster_size);
3537 	has_bigalloc = ext4_has_feature_bigalloc(sb);
3538 	if (has_bigalloc) {
3539 		if (clustersize < blocksize) {
3540 			ext4_msg(sb, KERN_ERR,
3541 				 "cluster size (%d) smaller than "
3542 				 "block size (%d)", clustersize, blocksize);
3543 			goto failed_mount;
3544 		}
3545 		sbi->s_cluster_bits = le32_to_cpu(es->s_log_cluster_size) -
3546 			le32_to_cpu(es->s_log_block_size);
3547 		sbi->s_clusters_per_group =
3548 			le32_to_cpu(es->s_clusters_per_group);
3549 		if (sbi->s_clusters_per_group > blocksize * 8) {
3550 			ext4_msg(sb, KERN_ERR,
3551 				 "#clusters per group too big: %lu",
3552 				 sbi->s_clusters_per_group);
3553 			goto failed_mount;
3554 		}
3555 		if (sbi->s_blocks_per_group !=
3556 		    (sbi->s_clusters_per_group * (clustersize / blocksize))) {
3557 			ext4_msg(sb, KERN_ERR, "blocks per group (%lu) and "
3558 				 "clusters per group (%lu) inconsistent",
3559 				 sbi->s_blocks_per_group,
3560 				 sbi->s_clusters_per_group);
3561 			goto failed_mount;
3562 		}
3563 	} else {
3564 		if (clustersize != blocksize) {
3565 			ext4_warning(sb, "fragment/cluster size (%d) != "
3566 				     "block size (%d)", clustersize,
3567 				     blocksize);
3568 			clustersize = blocksize;
3569 		}
3570 		if (sbi->s_blocks_per_group > blocksize * 8) {
3571 			ext4_msg(sb, KERN_ERR,
3572 				 "#blocks per group too big: %lu",
3573 				 sbi->s_blocks_per_group);
3574 			goto failed_mount;
3575 		}
3576 		sbi->s_clusters_per_group = sbi->s_blocks_per_group;
3577 		sbi->s_cluster_bits = 0;
3578 	}
3579 	sbi->s_cluster_ratio = clustersize / blocksize;
3580 
3581 	if (sbi->s_inodes_per_group > blocksize * 8) {
3582 		ext4_msg(sb, KERN_ERR,
3583 		       "#inodes per group too big: %lu",
3584 		       sbi->s_inodes_per_group);
3585 		goto failed_mount;
3586 	}
3587 
3588 	/* Do we have standard group size of clustersize * 8 blocks ? */
3589 	if (sbi->s_blocks_per_group == clustersize << 3)
3590 		set_opt2(sb, STD_GROUP_SIZE);
3591 
3592 	/*
3593 	 * Test whether we have more sectors than will fit in sector_t,
3594 	 * and whether the max offset is addressable by the page cache.
3595 	 */
3596 	err = generic_check_addressable(sb->s_blocksize_bits,
3597 					ext4_blocks_count(es));
3598 	if (err) {
3599 		ext4_msg(sb, KERN_ERR, "filesystem"
3600 			 " too large to mount safely on this system");
3601 		if (sizeof(sector_t) < 8)
3602 			ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled");
3603 		goto failed_mount;
3604 	}
3605 
3606 	if (EXT4_BLOCKS_PER_GROUP(sb) == 0)
3607 		goto cantfind_ext4;
3608 
3609 	/* check blocks count against device size */
3610 	blocks_count = sb->s_bdev->bd_inode->i_size >> sb->s_blocksize_bits;
3611 	if (blocks_count && ext4_blocks_count(es) > blocks_count) {
3612 		ext4_msg(sb, KERN_WARNING, "bad geometry: block count %llu "
3613 		       "exceeds size of device (%llu blocks)",
3614 		       ext4_blocks_count(es), blocks_count);
3615 		goto failed_mount;
3616 	}
3617 
3618 	/*
3619 	 * It makes no sense for the first data block to be beyond the end
3620 	 * of the filesystem.
3621 	 */
3622 	if (le32_to_cpu(es->s_first_data_block) >= ext4_blocks_count(es)) {
3623 		ext4_msg(sb, KERN_WARNING, "bad geometry: first data "
3624 			 "block %u is beyond end of filesystem (%llu)",
3625 			 le32_to_cpu(es->s_first_data_block),
3626 			 ext4_blocks_count(es));
3627 		goto failed_mount;
3628 	}
3629 	blocks_count = (ext4_blocks_count(es) -
3630 			le32_to_cpu(es->s_first_data_block) +
3631 			EXT4_BLOCKS_PER_GROUP(sb) - 1);
3632 	do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
3633 	if (blocks_count > ((uint64_t)1<<32) - EXT4_DESC_PER_BLOCK(sb)) {
3634 		ext4_msg(sb, KERN_WARNING, "groups count too large: %u "
3635 		       "(block count %llu, first data block %u, "
3636 		       "blocks per group %lu)", sbi->s_groups_count,
3637 		       ext4_blocks_count(es),
3638 		       le32_to_cpu(es->s_first_data_block),
3639 		       EXT4_BLOCKS_PER_GROUP(sb));
3640 		goto failed_mount;
3641 	}
3642 	sbi->s_groups_count = blocks_count;
3643 	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
3644 			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
3645 	db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
3646 		   EXT4_DESC_PER_BLOCK(sb);
3647 	sbi->s_group_desc = ext4_kvmalloc(db_count *
3648 					  sizeof(struct buffer_head *),
3649 					  GFP_KERNEL);
3650 	if (sbi->s_group_desc == NULL) {
3651 		ext4_msg(sb, KERN_ERR, "not enough memory");
3652 		ret = -ENOMEM;
3653 		goto failed_mount;
3654 	}
3655 
3656 	bgl_lock_init(sbi->s_blockgroup_lock);
3657 
3658 	for (i = 0; i < db_count; i++) {
3659 		block = descriptor_loc(sb, logical_sb_block, i);
3660 		sbi->s_group_desc[i] = sb_bread_unmovable(sb, block);
3661 		if (!sbi->s_group_desc[i]) {
3662 			ext4_msg(sb, KERN_ERR,
3663 			       "can't read group descriptor %d", i);
3664 			db_count = i;
3665 			goto failed_mount2;
3666 		}
3667 	}
3668 	if (!ext4_check_descriptors(sb, &first_not_zeroed)) {
3669 		ext4_msg(sb, KERN_ERR, "group descriptors corrupted!");
3670 		ret = -EFSCORRUPTED;
3671 		goto failed_mount2;
3672 	}
3673 
3674 	sbi->s_gdb_count = db_count;
3675 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
3676 	spin_lock_init(&sbi->s_next_gen_lock);
3677 
3678 	setup_timer(&sbi->s_err_report, print_daily_error_info,
3679 		(unsigned long) sb);
3680 
3681 	/* Register extent status tree shrinker */
3682 	if (ext4_es_register_shrinker(sbi))
3683 		goto failed_mount3;
3684 
3685 	sbi->s_stripe = ext4_get_stripe_size(sbi);
3686 	sbi->s_extent_max_zeroout_kb = 32;
3687 
3688 	/*
3689 	 * set up enough so that it can read an inode
3690 	 */
3691 	sb->s_op = &ext4_sops;
3692 	sb->s_export_op = &ext4_export_ops;
3693 	sb->s_xattr = ext4_xattr_handlers;
3694 #ifdef CONFIG_QUOTA
3695 	sb->dq_op = &ext4_quota_operations;
3696 	if (ext4_has_feature_quota(sb))
3697 		sb->s_qcop = &dquot_quotactl_sysfile_ops;
3698 	else
3699 		sb->s_qcop = &ext4_qctl_operations;
3700 	sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP | QTYPE_MASK_PRJ;
3701 #endif
3702 	memcpy(sb->s_uuid, es->s_uuid, sizeof(es->s_uuid));
3703 
3704 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
3705 	mutex_init(&sbi->s_orphan_lock);
3706 
3707 	sb->s_root = NULL;
3708 
3709 	needs_recovery = (es->s_last_orphan != 0 ||
3710 			  ext4_has_feature_journal_needs_recovery(sb));
3711 
3712 	if (ext4_has_feature_mmp(sb) && !(sb->s_flags & MS_RDONLY))
3713 		if (ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block)))
3714 			goto failed_mount3a;
3715 
3716 	/*
3717 	 * The first inode we look at is the journal inode.  Don't try
3718 	 * root first: it may be modified in the journal!
3719 	 */
3720 	if (!test_opt(sb, NOLOAD) && ext4_has_feature_journal(sb)) {
3721 		if (ext4_load_journal(sb, es, journal_devnum))
3722 			goto failed_mount3a;
3723 	} else if (test_opt(sb, NOLOAD) && !(sb->s_flags & MS_RDONLY) &&
3724 		   ext4_has_feature_journal_needs_recovery(sb)) {
3725 		ext4_msg(sb, KERN_ERR, "required journal recovery "
3726 		       "suppressed and not mounted read-only");
3727 		goto failed_mount_wq;
3728 	} else {
3729 		/* Nojournal mode, all journal mount options are illegal */
3730 		if (test_opt2(sb, EXPLICIT_JOURNAL_CHECKSUM)) {
3731 			ext4_msg(sb, KERN_ERR, "can't mount with "
3732 				 "journal_checksum, fs mounted w/o journal");
3733 			goto failed_mount_wq;
3734 		}
3735 		if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
3736 			ext4_msg(sb, KERN_ERR, "can't mount with "
3737 				 "journal_async_commit, fs mounted w/o journal");
3738 			goto failed_mount_wq;
3739 		}
3740 		if (sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ) {
3741 			ext4_msg(sb, KERN_ERR, "can't mount with "
3742 				 "commit=%lu, fs mounted w/o journal",
3743 				 sbi->s_commit_interval / HZ);
3744 			goto failed_mount_wq;
3745 		}
3746 		if (EXT4_MOUNT_DATA_FLAGS &
3747 		    (sbi->s_mount_opt ^ sbi->s_def_mount_opt)) {
3748 			ext4_msg(sb, KERN_ERR, "can't mount with "
3749 				 "data=, fs mounted w/o journal");
3750 			goto failed_mount_wq;
3751 		}
3752 		sbi->s_def_mount_opt &= EXT4_MOUNT_JOURNAL_CHECKSUM;
3753 		clear_opt(sb, JOURNAL_CHECKSUM);
3754 		clear_opt(sb, DATA_FLAGS);
3755 		sbi->s_journal = NULL;
3756 		needs_recovery = 0;
3757 		goto no_journal;
3758 	}
3759 
3760 	if (ext4_has_feature_64bit(sb) &&
3761 	    !jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
3762 				       JBD2_FEATURE_INCOMPAT_64BIT)) {
3763 		ext4_msg(sb, KERN_ERR, "Failed to set 64-bit journal feature");
3764 		goto failed_mount_wq;
3765 	}
3766 
3767 	if (!set_journal_csum_feature_set(sb)) {
3768 		ext4_msg(sb, KERN_ERR, "Failed to set journal checksum "
3769 			 "feature set");
3770 		goto failed_mount_wq;
3771 	}
3772 
3773 	/* We have now updated the journal if required, so we can
3774 	 * validate the data journaling mode. */
3775 	switch (test_opt(sb, DATA_FLAGS)) {
3776 	case 0:
3777 		/* No mode set, assume a default based on the journal
3778 		 * capabilities: ORDERED_DATA if the journal can
3779 		 * cope, else JOURNAL_DATA
3780 		 */
3781 		if (jbd2_journal_check_available_features
3782 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE))
3783 			set_opt(sb, ORDERED_DATA);
3784 		else
3785 			set_opt(sb, JOURNAL_DATA);
3786 		break;
3787 
3788 	case EXT4_MOUNT_ORDERED_DATA:
3789 	case EXT4_MOUNT_WRITEBACK_DATA:
3790 		if (!jbd2_journal_check_available_features
3791 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
3792 			ext4_msg(sb, KERN_ERR, "Journal does not support "
3793 			       "requested data journaling mode");
3794 			goto failed_mount_wq;
3795 		}
3796 	default:
3797 		break;
3798 	}
3799 	set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
3800 
3801 	sbi->s_journal->j_commit_callback = ext4_journal_commit_callback;
3802 
3803 no_journal:
3804 	sbi->s_mb_cache = ext4_xattr_create_cache();
3805 	if (!sbi->s_mb_cache) {
3806 		ext4_msg(sb, KERN_ERR, "Failed to create an mb_cache");
3807 		goto failed_mount_wq;
3808 	}
3809 
3810 	if ((DUMMY_ENCRYPTION_ENABLED(sbi) || ext4_has_feature_encrypt(sb)) &&
3811 	    (blocksize != PAGE_CACHE_SIZE)) {
3812 		ext4_msg(sb, KERN_ERR,
3813 			 "Unsupported blocksize for fs encryption");
3814 		goto failed_mount_wq;
3815 	}
3816 
3817 	if (DUMMY_ENCRYPTION_ENABLED(sbi) && !(sb->s_flags & MS_RDONLY) &&
3818 	    !ext4_has_feature_encrypt(sb)) {
3819 		ext4_set_feature_encrypt(sb);
3820 		ext4_commit_super(sb, 1);
3821 	}
3822 
3823 	/*
3824 	 * Get the # of file system overhead blocks from the
3825 	 * superblock if present.
3826 	 */
3827 	if (es->s_overhead_clusters)
3828 		sbi->s_overhead = le32_to_cpu(es->s_overhead_clusters);
3829 	else {
3830 		err = ext4_calculate_overhead(sb);
3831 		if (err)
3832 			goto failed_mount_wq;
3833 	}
3834 
3835 	/*
3836 	 * The maximum number of concurrent works can be high and
3837 	 * concurrency isn't really necessary.  Limit it to 1.
3838 	 */
3839 	EXT4_SB(sb)->rsv_conversion_wq =
3840 		alloc_workqueue("ext4-rsv-conversion", WQ_MEM_RECLAIM | WQ_UNBOUND, 1);
3841 	if (!EXT4_SB(sb)->rsv_conversion_wq) {
3842 		printk(KERN_ERR "EXT4-fs: failed to create workqueue\n");
3843 		ret = -ENOMEM;
3844 		goto failed_mount4;
3845 	}
3846 
3847 	/*
3848 	 * The jbd2_journal_load will have done any necessary log recovery,
3849 	 * so we can safely mount the rest of the filesystem now.
3850 	 */
3851 
3852 	root = ext4_iget(sb, EXT4_ROOT_INO);
3853 	if (IS_ERR(root)) {
3854 		ext4_msg(sb, KERN_ERR, "get root inode failed");
3855 		ret = PTR_ERR(root);
3856 		root = NULL;
3857 		goto failed_mount4;
3858 	}
3859 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
3860 		ext4_msg(sb, KERN_ERR, "corrupt root inode, run e2fsck");
3861 		iput(root);
3862 		goto failed_mount4;
3863 	}
3864 	sb->s_root = d_make_root(root);
3865 	if (!sb->s_root) {
3866 		ext4_msg(sb, KERN_ERR, "get root dentry failed");
3867 		ret = -ENOMEM;
3868 		goto failed_mount4;
3869 	}
3870 
3871 	if (ext4_setup_super(sb, es, sb->s_flags & MS_RDONLY))
3872 		sb->s_flags |= MS_RDONLY;
3873 
3874 	/* determine the minimum size of new large inodes, if present */
3875 	if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
3876 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
3877 						     EXT4_GOOD_OLD_INODE_SIZE;
3878 		if (ext4_has_feature_extra_isize(sb)) {
3879 			if (sbi->s_want_extra_isize <
3880 			    le16_to_cpu(es->s_want_extra_isize))
3881 				sbi->s_want_extra_isize =
3882 					le16_to_cpu(es->s_want_extra_isize);
3883 			if (sbi->s_want_extra_isize <
3884 			    le16_to_cpu(es->s_min_extra_isize))
3885 				sbi->s_want_extra_isize =
3886 					le16_to_cpu(es->s_min_extra_isize);
3887 		}
3888 	}
3889 	/* Check if enough inode space is available */
3890 	if (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize >
3891 							sbi->s_inode_size) {
3892 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
3893 						       EXT4_GOOD_OLD_INODE_SIZE;
3894 		ext4_msg(sb, KERN_INFO, "required extra inode space not"
3895 			 "available");
3896 	}
3897 
3898 	ext4_set_resv_clusters(sb);
3899 
3900 	err = ext4_setup_system_zone(sb);
3901 	if (err) {
3902 		ext4_msg(sb, KERN_ERR, "failed to initialize system "
3903 			 "zone (%d)", err);
3904 		goto failed_mount4a;
3905 	}
3906 
3907 	ext4_ext_init(sb);
3908 	err = ext4_mb_init(sb);
3909 	if (err) {
3910 		ext4_msg(sb, KERN_ERR, "failed to initialize mballoc (%d)",
3911 			 err);
3912 		goto failed_mount5;
3913 	}
3914 
3915 	block = ext4_count_free_clusters(sb);
3916 	ext4_free_blocks_count_set(sbi->s_es,
3917 				   EXT4_C2B(sbi, block));
3918 	err = percpu_counter_init(&sbi->s_freeclusters_counter, block,
3919 				  GFP_KERNEL);
3920 	if (!err) {
3921 		unsigned long freei = ext4_count_free_inodes(sb);
3922 		sbi->s_es->s_free_inodes_count = cpu_to_le32(freei);
3923 		err = percpu_counter_init(&sbi->s_freeinodes_counter, freei,
3924 					  GFP_KERNEL);
3925 	}
3926 	if (!err)
3927 		err = percpu_counter_init(&sbi->s_dirs_counter,
3928 					  ext4_count_dirs(sb), GFP_KERNEL);
3929 	if (!err)
3930 		err = percpu_counter_init(&sbi->s_dirtyclusters_counter, 0,
3931 					  GFP_KERNEL);
3932 	if (err) {
3933 		ext4_msg(sb, KERN_ERR, "insufficient memory");
3934 		goto failed_mount6;
3935 	}
3936 
3937 	if (ext4_has_feature_flex_bg(sb))
3938 		if (!ext4_fill_flex_info(sb)) {
3939 			ext4_msg(sb, KERN_ERR,
3940 			       "unable to initialize "
3941 			       "flex_bg meta info!");
3942 			goto failed_mount6;
3943 		}
3944 
3945 	err = ext4_register_li_request(sb, first_not_zeroed);
3946 	if (err)
3947 		goto failed_mount6;
3948 
3949 	err = ext4_register_sysfs(sb);
3950 	if (err)
3951 		goto failed_mount7;
3952 
3953 #ifdef CONFIG_QUOTA
3954 	/* Enable quota usage during mount. */
3955 	if (ext4_has_feature_quota(sb) && !(sb->s_flags & MS_RDONLY)) {
3956 		err = ext4_enable_quotas(sb);
3957 		if (err)
3958 			goto failed_mount8;
3959 	}
3960 #endif  /* CONFIG_QUOTA */
3961 
3962 	EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
3963 	ext4_orphan_cleanup(sb, es);
3964 	EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
3965 	if (needs_recovery) {
3966 		ext4_msg(sb, KERN_INFO, "recovery complete");
3967 		ext4_mark_recovery_complete(sb, es);
3968 	}
3969 	if (EXT4_SB(sb)->s_journal) {
3970 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
3971 			descr = " journalled data mode";
3972 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
3973 			descr = " ordered data mode";
3974 		else
3975 			descr = " writeback data mode";
3976 	} else
3977 		descr = "out journal";
3978 
3979 	if (test_opt(sb, DISCARD)) {
3980 		struct request_queue *q = bdev_get_queue(sb->s_bdev);
3981 		if (!blk_queue_discard(q))
3982 			ext4_msg(sb, KERN_WARNING,
3983 				 "mounting with \"discard\" option, but "
3984 				 "the device does not support discard");
3985 	}
3986 
3987 	if (___ratelimit(&ext4_mount_msg_ratelimit, "EXT4-fs mount"))
3988 		ext4_msg(sb, KERN_INFO, "mounted filesystem with%s. "
3989 			 "Opts: %s%s%s", descr, sbi->s_es->s_mount_opts,
3990 			 *sbi->s_es->s_mount_opts ? "; " : "", orig_data);
3991 
3992 	if (es->s_error_count)
3993 		mod_timer(&sbi->s_err_report, jiffies + 300*HZ); /* 5 minutes */
3994 
3995 	/* Enable message ratelimiting. Default is 10 messages per 5 secs. */
3996 	ratelimit_state_init(&sbi->s_err_ratelimit_state, 5 * HZ, 10);
3997 	ratelimit_state_init(&sbi->s_warning_ratelimit_state, 5 * HZ, 10);
3998 	ratelimit_state_init(&sbi->s_msg_ratelimit_state, 5 * HZ, 10);
3999 
4000 	kfree(orig_data);
4001 	return 0;
4002 
4003 cantfind_ext4:
4004 	if (!silent)
4005 		ext4_msg(sb, KERN_ERR, "VFS: Can't find ext4 filesystem");
4006 	goto failed_mount;
4007 
4008 #ifdef CONFIG_QUOTA
4009 failed_mount8:
4010 	ext4_unregister_sysfs(sb);
4011 #endif
4012 failed_mount7:
4013 	ext4_unregister_li_request(sb);
4014 failed_mount6:
4015 	ext4_mb_release(sb);
4016 	if (sbi->s_flex_groups)
4017 		kvfree(sbi->s_flex_groups);
4018 	percpu_counter_destroy(&sbi->s_freeclusters_counter);
4019 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
4020 	percpu_counter_destroy(&sbi->s_dirs_counter);
4021 	percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
4022 failed_mount5:
4023 	ext4_ext_release(sb);
4024 	ext4_release_system_zone(sb);
4025 failed_mount4a:
4026 	dput(sb->s_root);
4027 	sb->s_root = NULL;
4028 failed_mount4:
4029 	ext4_msg(sb, KERN_ERR, "mount failed");
4030 	if (EXT4_SB(sb)->rsv_conversion_wq)
4031 		destroy_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
4032 failed_mount_wq:
4033 	if (sbi->s_mb_cache) {
4034 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
4035 		sbi->s_mb_cache = NULL;
4036 	}
4037 	if (sbi->s_journal) {
4038 		jbd2_journal_destroy(sbi->s_journal);
4039 		sbi->s_journal = NULL;
4040 	}
4041 failed_mount3a:
4042 	ext4_es_unregister_shrinker(sbi);
4043 failed_mount3:
4044 	del_timer_sync(&sbi->s_err_report);
4045 	if (sbi->s_mmp_tsk)
4046 		kthread_stop(sbi->s_mmp_tsk);
4047 failed_mount2:
4048 	for (i = 0; i < db_count; i++)
4049 		brelse(sbi->s_group_desc[i]);
4050 	kvfree(sbi->s_group_desc);
4051 failed_mount:
4052 	if (sbi->s_chksum_driver)
4053 		crypto_free_shash(sbi->s_chksum_driver);
4054 #ifdef CONFIG_QUOTA
4055 	for (i = 0; i < EXT4_MAXQUOTAS; i++)
4056 		kfree(sbi->s_qf_names[i]);
4057 #endif
4058 	ext4_blkdev_remove(sbi);
4059 	brelse(bh);
4060 out_fail:
4061 	sb->s_fs_info = NULL;
4062 	kfree(sbi->s_blockgroup_lock);
4063 	kfree(sbi);
4064 out_free_orig:
4065 	kfree(orig_data);
4066 	return err ? err : ret;
4067 }
4068 
4069 /*
4070  * Setup any per-fs journal parameters now.  We'll do this both on
4071  * initial mount, once the journal has been initialised but before we've
4072  * done any recovery; and again on any subsequent remount.
4073  */
4074 static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
4075 {
4076 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4077 
4078 	journal->j_commit_interval = sbi->s_commit_interval;
4079 	journal->j_min_batch_time = sbi->s_min_batch_time;
4080 	journal->j_max_batch_time = sbi->s_max_batch_time;
4081 
4082 	write_lock(&journal->j_state_lock);
4083 	if (test_opt(sb, BARRIER))
4084 		journal->j_flags |= JBD2_BARRIER;
4085 	else
4086 		journal->j_flags &= ~JBD2_BARRIER;
4087 	if (test_opt(sb, DATA_ERR_ABORT))
4088 		journal->j_flags |= JBD2_ABORT_ON_SYNCDATA_ERR;
4089 	else
4090 		journal->j_flags &= ~JBD2_ABORT_ON_SYNCDATA_ERR;
4091 	write_unlock(&journal->j_state_lock);
4092 }
4093 
4094 static journal_t *ext4_get_journal(struct super_block *sb,
4095 				   unsigned int journal_inum)
4096 {
4097 	struct inode *journal_inode;
4098 	journal_t *journal;
4099 
4100 	BUG_ON(!ext4_has_feature_journal(sb));
4101 
4102 	/* First, test for the existence of a valid inode on disk.  Bad
4103 	 * things happen if we iget() an unused inode, as the subsequent
4104 	 * iput() will try to delete it. */
4105 
4106 	journal_inode = ext4_iget(sb, journal_inum);
4107 	if (IS_ERR(journal_inode)) {
4108 		ext4_msg(sb, KERN_ERR, "no journal found");
4109 		return NULL;
4110 	}
4111 	if (!journal_inode->i_nlink) {
4112 		make_bad_inode(journal_inode);
4113 		iput(journal_inode);
4114 		ext4_msg(sb, KERN_ERR, "journal inode is deleted");
4115 		return NULL;
4116 	}
4117 
4118 	jbd_debug(2, "Journal inode found at %p: %lld bytes\n",
4119 		  journal_inode, journal_inode->i_size);
4120 	if (!S_ISREG(journal_inode->i_mode)) {
4121 		ext4_msg(sb, KERN_ERR, "invalid journal inode");
4122 		iput(journal_inode);
4123 		return NULL;
4124 	}
4125 
4126 	journal = jbd2_journal_init_inode(journal_inode);
4127 	if (!journal) {
4128 		ext4_msg(sb, KERN_ERR, "Could not load journal inode");
4129 		iput(journal_inode);
4130 		return NULL;
4131 	}
4132 	journal->j_private = sb;
4133 	ext4_init_journal_params(sb, journal);
4134 	return journal;
4135 }
4136 
4137 static journal_t *ext4_get_dev_journal(struct super_block *sb,
4138 				       dev_t j_dev)
4139 {
4140 	struct buffer_head *bh;
4141 	journal_t *journal;
4142 	ext4_fsblk_t start;
4143 	ext4_fsblk_t len;
4144 	int hblock, blocksize;
4145 	ext4_fsblk_t sb_block;
4146 	unsigned long offset;
4147 	struct ext4_super_block *es;
4148 	struct block_device *bdev;
4149 
4150 	BUG_ON(!ext4_has_feature_journal(sb));
4151 
4152 	bdev = ext4_blkdev_get(j_dev, sb);
4153 	if (bdev == NULL)
4154 		return NULL;
4155 
4156 	blocksize = sb->s_blocksize;
4157 	hblock = bdev_logical_block_size(bdev);
4158 	if (blocksize < hblock) {
4159 		ext4_msg(sb, KERN_ERR,
4160 			"blocksize too small for journal device");
4161 		goto out_bdev;
4162 	}
4163 
4164 	sb_block = EXT4_MIN_BLOCK_SIZE / blocksize;
4165 	offset = EXT4_MIN_BLOCK_SIZE % blocksize;
4166 	set_blocksize(bdev, blocksize);
4167 	if (!(bh = __bread(bdev, sb_block, blocksize))) {
4168 		ext4_msg(sb, KERN_ERR, "couldn't read superblock of "
4169 		       "external journal");
4170 		goto out_bdev;
4171 	}
4172 
4173 	es = (struct ext4_super_block *) (bh->b_data + offset);
4174 	if ((le16_to_cpu(es->s_magic) != EXT4_SUPER_MAGIC) ||
4175 	    !(le32_to_cpu(es->s_feature_incompat) &
4176 	      EXT4_FEATURE_INCOMPAT_JOURNAL_DEV)) {
4177 		ext4_msg(sb, KERN_ERR, "external journal has "
4178 					"bad superblock");
4179 		brelse(bh);
4180 		goto out_bdev;
4181 	}
4182 
4183 	if ((le32_to_cpu(es->s_feature_ro_compat) &
4184 	     EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
4185 	    es->s_checksum != ext4_superblock_csum(sb, es)) {
4186 		ext4_msg(sb, KERN_ERR, "external journal has "
4187 				       "corrupt superblock");
4188 		brelse(bh);
4189 		goto out_bdev;
4190 	}
4191 
4192 	if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
4193 		ext4_msg(sb, KERN_ERR, "journal UUID does not match");
4194 		brelse(bh);
4195 		goto out_bdev;
4196 	}
4197 
4198 	len = ext4_blocks_count(es);
4199 	start = sb_block + 1;
4200 	brelse(bh);	/* we're done with the superblock */
4201 
4202 	journal = jbd2_journal_init_dev(bdev, sb->s_bdev,
4203 					start, len, blocksize);
4204 	if (!journal) {
4205 		ext4_msg(sb, KERN_ERR, "failed to create device journal");
4206 		goto out_bdev;
4207 	}
4208 	journal->j_private = sb;
4209 	ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &journal->j_sb_buffer);
4210 	wait_on_buffer(journal->j_sb_buffer);
4211 	if (!buffer_uptodate(journal->j_sb_buffer)) {
4212 		ext4_msg(sb, KERN_ERR, "I/O error on journal device");
4213 		goto out_journal;
4214 	}
4215 	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
4216 		ext4_msg(sb, KERN_ERR, "External journal has more than one "
4217 					"user (unsupported) - %d",
4218 			be32_to_cpu(journal->j_superblock->s_nr_users));
4219 		goto out_journal;
4220 	}
4221 	EXT4_SB(sb)->journal_bdev = bdev;
4222 	ext4_init_journal_params(sb, journal);
4223 	return journal;
4224 
4225 out_journal:
4226 	jbd2_journal_destroy(journal);
4227 out_bdev:
4228 	ext4_blkdev_put(bdev);
4229 	return NULL;
4230 }
4231 
4232 static int ext4_load_journal(struct super_block *sb,
4233 			     struct ext4_super_block *es,
4234 			     unsigned long journal_devnum)
4235 {
4236 	journal_t *journal;
4237 	unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
4238 	dev_t journal_dev;
4239 	int err = 0;
4240 	int really_read_only;
4241 
4242 	BUG_ON(!ext4_has_feature_journal(sb));
4243 
4244 	if (journal_devnum &&
4245 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
4246 		ext4_msg(sb, KERN_INFO, "external journal device major/minor "
4247 			"numbers have changed");
4248 		journal_dev = new_decode_dev(journal_devnum);
4249 	} else
4250 		journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));
4251 
4252 	really_read_only = bdev_read_only(sb->s_bdev);
4253 
4254 	/*
4255 	 * Are we loading a blank journal or performing recovery after a
4256 	 * crash?  For recovery, we need to check in advance whether we
4257 	 * can get read-write access to the device.
4258 	 */
4259 	if (ext4_has_feature_journal_needs_recovery(sb)) {
4260 		if (sb->s_flags & MS_RDONLY) {
4261 			ext4_msg(sb, KERN_INFO, "INFO: recovery "
4262 					"required on readonly filesystem");
4263 			if (really_read_only) {
4264 				ext4_msg(sb, KERN_ERR, "write access "
4265 					"unavailable, cannot proceed");
4266 				return -EROFS;
4267 			}
4268 			ext4_msg(sb, KERN_INFO, "write access will "
4269 			       "be enabled during recovery");
4270 		}
4271 	}
4272 
4273 	if (journal_inum && journal_dev) {
4274 		ext4_msg(sb, KERN_ERR, "filesystem has both journal "
4275 		       "and inode journals!");
4276 		return -EINVAL;
4277 	}
4278 
4279 	if (journal_inum) {
4280 		if (!(journal = ext4_get_journal(sb, journal_inum)))
4281 			return -EINVAL;
4282 	} else {
4283 		if (!(journal = ext4_get_dev_journal(sb, journal_dev)))
4284 			return -EINVAL;
4285 	}
4286 
4287 	if (!(journal->j_flags & JBD2_BARRIER))
4288 		ext4_msg(sb, KERN_INFO, "barriers disabled");
4289 
4290 	if (!ext4_has_feature_journal_needs_recovery(sb))
4291 		err = jbd2_journal_wipe(journal, !really_read_only);
4292 	if (!err) {
4293 		char *save = kmalloc(EXT4_S_ERR_LEN, GFP_KERNEL);
4294 		if (save)
4295 			memcpy(save, ((char *) es) +
4296 			       EXT4_S_ERR_START, EXT4_S_ERR_LEN);
4297 		err = jbd2_journal_load(journal);
4298 		if (save)
4299 			memcpy(((char *) es) + EXT4_S_ERR_START,
4300 			       save, EXT4_S_ERR_LEN);
4301 		kfree(save);
4302 	}
4303 
4304 	if (err) {
4305 		ext4_msg(sb, KERN_ERR, "error loading journal");
4306 		jbd2_journal_destroy(journal);
4307 		return err;
4308 	}
4309 
4310 	EXT4_SB(sb)->s_journal = journal;
4311 	ext4_clear_journal_err(sb, es);
4312 
4313 	if (!really_read_only && journal_devnum &&
4314 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
4315 		es->s_journal_dev = cpu_to_le32(journal_devnum);
4316 
4317 		/* Make sure we flush the recovery flag to disk. */
4318 		ext4_commit_super(sb, 1);
4319 	}
4320 
4321 	return 0;
4322 }
4323 
4324 static int ext4_commit_super(struct super_block *sb, int sync)
4325 {
4326 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
4327 	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
4328 	int error = 0;
4329 
4330 	if (!sbh || block_device_ejected(sb))
4331 		return error;
4332 	if (buffer_write_io_error(sbh)) {
4333 		/*
4334 		 * Oh, dear.  A previous attempt to write the
4335 		 * superblock failed.  This could happen because the
4336 		 * USB device was yanked out.  Or it could happen to
4337 		 * be a transient write error and maybe the block will
4338 		 * be remapped.  Nothing we can do but to retry the
4339 		 * write and hope for the best.
4340 		 */
4341 		ext4_msg(sb, KERN_ERR, "previous I/O error to "
4342 		       "superblock detected");
4343 		clear_buffer_write_io_error(sbh);
4344 		set_buffer_uptodate(sbh);
4345 	}
4346 	/*
4347 	 * If the file system is mounted read-only, don't update the
4348 	 * superblock write time.  This avoids updating the superblock
4349 	 * write time when we are mounting the root file system
4350 	 * read/only but we need to replay the journal; at that point,
4351 	 * for people who are east of GMT and who make their clock
4352 	 * tick in localtime for Windows bug-for-bug compatibility,
4353 	 * the clock is set in the future, and this will cause e2fsck
4354 	 * to complain and force a full file system check.
4355 	 */
4356 	if (!(sb->s_flags & MS_RDONLY))
4357 		es->s_wtime = cpu_to_le32(get_seconds());
4358 	if (sb->s_bdev->bd_part)
4359 		es->s_kbytes_written =
4360 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written +
4361 			    ((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
4362 			      EXT4_SB(sb)->s_sectors_written_start) >> 1));
4363 	else
4364 		es->s_kbytes_written =
4365 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written);
4366 	if (percpu_counter_initialized(&EXT4_SB(sb)->s_freeclusters_counter))
4367 		ext4_free_blocks_count_set(es,
4368 			EXT4_C2B(EXT4_SB(sb), percpu_counter_sum_positive(
4369 				&EXT4_SB(sb)->s_freeclusters_counter)));
4370 	if (percpu_counter_initialized(&EXT4_SB(sb)->s_freeinodes_counter))
4371 		es->s_free_inodes_count =
4372 			cpu_to_le32(percpu_counter_sum_positive(
4373 				&EXT4_SB(sb)->s_freeinodes_counter));
4374 	BUFFER_TRACE(sbh, "marking dirty");
4375 	ext4_superblock_csum_set(sb);
4376 	mark_buffer_dirty(sbh);
4377 	if (sync) {
4378 		error = __sync_dirty_buffer(sbh,
4379 			test_opt(sb, BARRIER) ? WRITE_FUA : WRITE_SYNC);
4380 		if (error)
4381 			return error;
4382 
4383 		error = buffer_write_io_error(sbh);
4384 		if (error) {
4385 			ext4_msg(sb, KERN_ERR, "I/O error while writing "
4386 			       "superblock");
4387 			clear_buffer_write_io_error(sbh);
4388 			set_buffer_uptodate(sbh);
4389 		}
4390 	}
4391 	return error;
4392 }
4393 
4394 /*
4395  * Have we just finished recovery?  If so, and if we are mounting (or
4396  * remounting) the filesystem readonly, then we will end up with a
4397  * consistent fs on disk.  Record that fact.
4398  */
4399 static void ext4_mark_recovery_complete(struct super_block *sb,
4400 					struct ext4_super_block *es)
4401 {
4402 	journal_t *journal = EXT4_SB(sb)->s_journal;
4403 
4404 	if (!ext4_has_feature_journal(sb)) {
4405 		BUG_ON(journal != NULL);
4406 		return;
4407 	}
4408 	jbd2_journal_lock_updates(journal);
4409 	if (jbd2_journal_flush(journal) < 0)
4410 		goto out;
4411 
4412 	if (ext4_has_feature_journal_needs_recovery(sb) &&
4413 	    sb->s_flags & MS_RDONLY) {
4414 		ext4_clear_feature_journal_needs_recovery(sb);
4415 		ext4_commit_super(sb, 1);
4416 	}
4417 
4418 out:
4419 	jbd2_journal_unlock_updates(journal);
4420 }
4421 
4422 /*
4423  * If we are mounting (or read-write remounting) a filesystem whose journal
4424  * has recorded an error from a previous lifetime, move that error to the
4425  * main filesystem now.
4426  */
4427 static void ext4_clear_journal_err(struct super_block *sb,
4428 				   struct ext4_super_block *es)
4429 {
4430 	journal_t *journal;
4431 	int j_errno;
4432 	const char *errstr;
4433 
4434 	BUG_ON(!ext4_has_feature_journal(sb));
4435 
4436 	journal = EXT4_SB(sb)->s_journal;
4437 
4438 	/*
4439 	 * Now check for any error status which may have been recorded in the
4440 	 * journal by a prior ext4_error() or ext4_abort()
4441 	 */
4442 
4443 	j_errno = jbd2_journal_errno(journal);
4444 	if (j_errno) {
4445 		char nbuf[16];
4446 
4447 		errstr = ext4_decode_error(sb, j_errno, nbuf);
4448 		ext4_warning(sb, "Filesystem error recorded "
4449 			     "from previous mount: %s", errstr);
4450 		ext4_warning(sb, "Marking fs in need of filesystem check.");
4451 
4452 		EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
4453 		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
4454 		ext4_commit_super(sb, 1);
4455 
4456 		jbd2_journal_clear_err(journal);
4457 		jbd2_journal_update_sb_errno(journal);
4458 	}
4459 }
4460 
4461 /*
4462  * Force the running and committing transactions to commit,
4463  * and wait on the commit.
4464  */
4465 int ext4_force_commit(struct super_block *sb)
4466 {
4467 	journal_t *journal;
4468 
4469 	if (sb->s_flags & MS_RDONLY)
4470 		return 0;
4471 
4472 	journal = EXT4_SB(sb)->s_journal;
4473 	return ext4_journal_force_commit(journal);
4474 }
4475 
4476 static int ext4_sync_fs(struct super_block *sb, int wait)
4477 {
4478 	int ret = 0;
4479 	tid_t target;
4480 	bool needs_barrier = false;
4481 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4482 
4483 	trace_ext4_sync_fs(sb, wait);
4484 	flush_workqueue(sbi->rsv_conversion_wq);
4485 	/*
4486 	 * Writeback quota in non-journalled quota case - journalled quota has
4487 	 * no dirty dquots
4488 	 */
4489 	dquot_writeback_dquots(sb, -1);
4490 	/*
4491 	 * Data writeback is possible w/o journal transaction, so barrier must
4492 	 * being sent at the end of the function. But we can skip it if
4493 	 * transaction_commit will do it for us.
4494 	 */
4495 	if (sbi->s_journal) {
4496 		target = jbd2_get_latest_transaction(sbi->s_journal);
4497 		if (wait && sbi->s_journal->j_flags & JBD2_BARRIER &&
4498 		    !jbd2_trans_will_send_data_barrier(sbi->s_journal, target))
4499 			needs_barrier = true;
4500 
4501 		if (jbd2_journal_start_commit(sbi->s_journal, &target)) {
4502 			if (wait)
4503 				ret = jbd2_log_wait_commit(sbi->s_journal,
4504 							   target);
4505 		}
4506 	} else if (wait && test_opt(sb, BARRIER))
4507 		needs_barrier = true;
4508 	if (needs_barrier) {
4509 		int err;
4510 		err = blkdev_issue_flush(sb->s_bdev, GFP_KERNEL, NULL);
4511 		if (!ret)
4512 			ret = err;
4513 	}
4514 
4515 	return ret;
4516 }
4517 
4518 /*
4519  * LVM calls this function before a (read-only) snapshot is created.  This
4520  * gives us a chance to flush the journal completely and mark the fs clean.
4521  *
4522  * Note that only this function cannot bring a filesystem to be in a clean
4523  * state independently. It relies on upper layer to stop all data & metadata
4524  * modifications.
4525  */
4526 static int ext4_freeze(struct super_block *sb)
4527 {
4528 	int error = 0;
4529 	journal_t *journal;
4530 
4531 	if (sb->s_flags & MS_RDONLY)
4532 		return 0;
4533 
4534 	journal = EXT4_SB(sb)->s_journal;
4535 
4536 	if (journal) {
4537 		/* Now we set up the journal barrier. */
4538 		jbd2_journal_lock_updates(journal);
4539 
4540 		/*
4541 		 * Don't clear the needs_recovery flag if we failed to
4542 		 * flush the journal.
4543 		 */
4544 		error = jbd2_journal_flush(journal);
4545 		if (error < 0)
4546 			goto out;
4547 
4548 		/* Journal blocked and flushed, clear needs_recovery flag. */
4549 		ext4_clear_feature_journal_needs_recovery(sb);
4550 	}
4551 
4552 	error = ext4_commit_super(sb, 1);
4553 out:
4554 	if (journal)
4555 		/* we rely on upper layer to stop further updates */
4556 		jbd2_journal_unlock_updates(journal);
4557 	return error;
4558 }
4559 
4560 /*
4561  * Called by LVM after the snapshot is done.  We need to reset the RECOVER
4562  * flag here, even though the filesystem is not technically dirty yet.
4563  */
4564 static int ext4_unfreeze(struct super_block *sb)
4565 {
4566 	if (sb->s_flags & MS_RDONLY)
4567 		return 0;
4568 
4569 	if (EXT4_SB(sb)->s_journal) {
4570 		/* Reset the needs_recovery flag before the fs is unlocked. */
4571 		ext4_set_feature_journal_needs_recovery(sb);
4572 	}
4573 
4574 	ext4_commit_super(sb, 1);
4575 	return 0;
4576 }
4577 
4578 /*
4579  * Structure to save mount options for ext4_remount's benefit
4580  */
4581 struct ext4_mount_options {
4582 	unsigned long s_mount_opt;
4583 	unsigned long s_mount_opt2;
4584 	kuid_t s_resuid;
4585 	kgid_t s_resgid;
4586 	unsigned long s_commit_interval;
4587 	u32 s_min_batch_time, s_max_batch_time;
4588 #ifdef CONFIG_QUOTA
4589 	int s_jquota_fmt;
4590 	char *s_qf_names[EXT4_MAXQUOTAS];
4591 #endif
4592 };
4593 
4594 static int ext4_remount(struct super_block *sb, int *flags, char *data)
4595 {
4596 	struct ext4_super_block *es;
4597 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4598 	unsigned long old_sb_flags;
4599 	struct ext4_mount_options old_opts;
4600 	int enable_quota = 0;
4601 	ext4_group_t g;
4602 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
4603 	int err = 0;
4604 #ifdef CONFIG_QUOTA
4605 	int i, j;
4606 #endif
4607 	char *orig_data = kstrdup(data, GFP_KERNEL);
4608 
4609 	/* Store the original options */
4610 	old_sb_flags = sb->s_flags;
4611 	old_opts.s_mount_opt = sbi->s_mount_opt;
4612 	old_opts.s_mount_opt2 = sbi->s_mount_opt2;
4613 	old_opts.s_resuid = sbi->s_resuid;
4614 	old_opts.s_resgid = sbi->s_resgid;
4615 	old_opts.s_commit_interval = sbi->s_commit_interval;
4616 	old_opts.s_min_batch_time = sbi->s_min_batch_time;
4617 	old_opts.s_max_batch_time = sbi->s_max_batch_time;
4618 #ifdef CONFIG_QUOTA
4619 	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
4620 	for (i = 0; i < EXT4_MAXQUOTAS; i++)
4621 		if (sbi->s_qf_names[i]) {
4622 			old_opts.s_qf_names[i] = kstrdup(sbi->s_qf_names[i],
4623 							 GFP_KERNEL);
4624 			if (!old_opts.s_qf_names[i]) {
4625 				for (j = 0; j < i; j++)
4626 					kfree(old_opts.s_qf_names[j]);
4627 				kfree(orig_data);
4628 				return -ENOMEM;
4629 			}
4630 		} else
4631 			old_opts.s_qf_names[i] = NULL;
4632 #endif
4633 	if (sbi->s_journal && sbi->s_journal->j_task->io_context)
4634 		journal_ioprio = sbi->s_journal->j_task->io_context->ioprio;
4635 
4636 	if (!parse_options(data, sb, NULL, &journal_ioprio, 1)) {
4637 		err = -EINVAL;
4638 		goto restore_opts;
4639 	}
4640 
4641 	if ((old_opts.s_mount_opt & EXT4_MOUNT_JOURNAL_CHECKSUM) ^
4642 	    test_opt(sb, JOURNAL_CHECKSUM)) {
4643 		ext4_msg(sb, KERN_ERR, "changing journal_checksum "
4644 			 "during remount not supported; ignoring");
4645 		sbi->s_mount_opt ^= EXT4_MOUNT_JOURNAL_CHECKSUM;
4646 	}
4647 
4648 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
4649 		if (test_opt2(sb, EXPLICIT_DELALLOC)) {
4650 			ext4_msg(sb, KERN_ERR, "can't mount with "
4651 				 "both data=journal and delalloc");
4652 			err = -EINVAL;
4653 			goto restore_opts;
4654 		}
4655 		if (test_opt(sb, DIOREAD_NOLOCK)) {
4656 			ext4_msg(sb, KERN_ERR, "can't mount with "
4657 				 "both data=journal and dioread_nolock");
4658 			err = -EINVAL;
4659 			goto restore_opts;
4660 		}
4661 		if (test_opt(sb, DAX)) {
4662 			ext4_msg(sb, KERN_ERR, "can't mount with "
4663 				 "both data=journal and dax");
4664 			err = -EINVAL;
4665 			goto restore_opts;
4666 		}
4667 	}
4668 
4669 	if ((sbi->s_mount_opt ^ old_opts.s_mount_opt) & EXT4_MOUNT_DAX) {
4670 		ext4_msg(sb, KERN_WARNING, "warning: refusing change of "
4671 			"dax flag with busy inodes while remounting");
4672 		sbi->s_mount_opt ^= EXT4_MOUNT_DAX;
4673 	}
4674 
4675 	if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
4676 		ext4_abort(sb, "Abort forced by user");
4677 
4678 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
4679 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
4680 
4681 	es = sbi->s_es;
4682 
4683 	if (sbi->s_journal) {
4684 		ext4_init_journal_params(sb, sbi->s_journal);
4685 		set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
4686 	}
4687 
4688 	if (*flags & MS_LAZYTIME)
4689 		sb->s_flags |= MS_LAZYTIME;
4690 
4691 	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY)) {
4692 		if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) {
4693 			err = -EROFS;
4694 			goto restore_opts;
4695 		}
4696 
4697 		if (*flags & MS_RDONLY) {
4698 			err = sync_filesystem(sb);
4699 			if (err < 0)
4700 				goto restore_opts;
4701 			err = dquot_suspend(sb, -1);
4702 			if (err < 0)
4703 				goto restore_opts;
4704 
4705 			/*
4706 			 * First of all, the unconditional stuff we have to do
4707 			 * to disable replay of the journal when we next remount
4708 			 */
4709 			sb->s_flags |= MS_RDONLY;
4710 
4711 			/*
4712 			 * OK, test if we are remounting a valid rw partition
4713 			 * readonly, and if so set the rdonly flag and then
4714 			 * mark the partition as valid again.
4715 			 */
4716 			if (!(es->s_state & cpu_to_le16(EXT4_VALID_FS)) &&
4717 			    (sbi->s_mount_state & EXT4_VALID_FS))
4718 				es->s_state = cpu_to_le16(sbi->s_mount_state);
4719 
4720 			if (sbi->s_journal)
4721 				ext4_mark_recovery_complete(sb, es);
4722 		} else {
4723 			/* Make sure we can mount this feature set readwrite */
4724 			if (ext4_has_feature_readonly(sb) ||
4725 			    !ext4_feature_set_ok(sb, 0)) {
4726 				err = -EROFS;
4727 				goto restore_opts;
4728 			}
4729 			/*
4730 			 * Make sure the group descriptor checksums
4731 			 * are sane.  If they aren't, refuse to remount r/w.
4732 			 */
4733 			for (g = 0; g < sbi->s_groups_count; g++) {
4734 				struct ext4_group_desc *gdp =
4735 					ext4_get_group_desc(sb, g, NULL);
4736 
4737 				if (!ext4_group_desc_csum_verify(sb, g, gdp)) {
4738 					ext4_msg(sb, KERN_ERR,
4739 	       "ext4_remount: Checksum for group %u failed (%u!=%u)",
4740 		g, le16_to_cpu(ext4_group_desc_csum(sb, g, gdp)),
4741 					       le16_to_cpu(gdp->bg_checksum));
4742 					err = -EFSBADCRC;
4743 					goto restore_opts;
4744 				}
4745 			}
4746 
4747 			/*
4748 			 * If we have an unprocessed orphan list hanging
4749 			 * around from a previously readonly bdev mount,
4750 			 * require a full umount/remount for now.
4751 			 */
4752 			if (es->s_last_orphan) {
4753 				ext4_msg(sb, KERN_WARNING, "Couldn't "
4754 				       "remount RDWR because of unprocessed "
4755 				       "orphan inode list.  Please "
4756 				       "umount/remount instead");
4757 				err = -EINVAL;
4758 				goto restore_opts;
4759 			}
4760 
4761 			/*
4762 			 * Mounting a RDONLY partition read-write, so reread
4763 			 * and store the current valid flag.  (It may have
4764 			 * been changed by e2fsck since we originally mounted
4765 			 * the partition.)
4766 			 */
4767 			if (sbi->s_journal)
4768 				ext4_clear_journal_err(sb, es);
4769 			sbi->s_mount_state = le16_to_cpu(es->s_state);
4770 			if (!ext4_setup_super(sb, es, 0))
4771 				sb->s_flags &= ~MS_RDONLY;
4772 			if (ext4_has_feature_mmp(sb))
4773 				if (ext4_multi_mount_protect(sb,
4774 						le64_to_cpu(es->s_mmp_block))) {
4775 					err = -EROFS;
4776 					goto restore_opts;
4777 				}
4778 			enable_quota = 1;
4779 		}
4780 	}
4781 
4782 	/*
4783 	 * Reinitialize lazy itable initialization thread based on
4784 	 * current settings
4785 	 */
4786 	if ((sb->s_flags & MS_RDONLY) || !test_opt(sb, INIT_INODE_TABLE))
4787 		ext4_unregister_li_request(sb);
4788 	else {
4789 		ext4_group_t first_not_zeroed;
4790 		first_not_zeroed = ext4_has_uninit_itable(sb);
4791 		ext4_register_li_request(sb, first_not_zeroed);
4792 	}
4793 
4794 	ext4_setup_system_zone(sb);
4795 	if (sbi->s_journal == NULL && !(old_sb_flags & MS_RDONLY))
4796 		ext4_commit_super(sb, 1);
4797 
4798 #ifdef CONFIG_QUOTA
4799 	/* Release old quota file names */
4800 	for (i = 0; i < EXT4_MAXQUOTAS; i++)
4801 		kfree(old_opts.s_qf_names[i]);
4802 	if (enable_quota) {
4803 		if (sb_any_quota_suspended(sb))
4804 			dquot_resume(sb, -1);
4805 		else if (ext4_has_feature_quota(sb)) {
4806 			err = ext4_enable_quotas(sb);
4807 			if (err)
4808 				goto restore_opts;
4809 		}
4810 	}
4811 #endif
4812 
4813 	*flags = (*flags & ~MS_LAZYTIME) | (sb->s_flags & MS_LAZYTIME);
4814 	ext4_msg(sb, KERN_INFO, "re-mounted. Opts: %s", orig_data);
4815 	kfree(orig_data);
4816 	return 0;
4817 
4818 restore_opts:
4819 	sb->s_flags = old_sb_flags;
4820 	sbi->s_mount_opt = old_opts.s_mount_opt;
4821 	sbi->s_mount_opt2 = old_opts.s_mount_opt2;
4822 	sbi->s_resuid = old_opts.s_resuid;
4823 	sbi->s_resgid = old_opts.s_resgid;
4824 	sbi->s_commit_interval = old_opts.s_commit_interval;
4825 	sbi->s_min_batch_time = old_opts.s_min_batch_time;
4826 	sbi->s_max_batch_time = old_opts.s_max_batch_time;
4827 #ifdef CONFIG_QUOTA
4828 	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
4829 	for (i = 0; i < EXT4_MAXQUOTAS; i++) {
4830 		kfree(sbi->s_qf_names[i]);
4831 		sbi->s_qf_names[i] = old_opts.s_qf_names[i];
4832 	}
4833 #endif
4834 	kfree(orig_data);
4835 	return err;
4836 }
4837 
4838 #ifdef CONFIG_QUOTA
4839 static int ext4_statfs_project(struct super_block *sb,
4840 			       kprojid_t projid, struct kstatfs *buf)
4841 {
4842 	struct kqid qid;
4843 	struct dquot *dquot;
4844 	u64 limit;
4845 	u64 curblock;
4846 
4847 	qid = make_kqid_projid(projid);
4848 	dquot = dqget(sb, qid);
4849 	if (IS_ERR(dquot))
4850 		return PTR_ERR(dquot);
4851 	spin_lock(&dq_data_lock);
4852 
4853 	limit = (dquot->dq_dqb.dqb_bsoftlimit ?
4854 		 dquot->dq_dqb.dqb_bsoftlimit :
4855 		 dquot->dq_dqb.dqb_bhardlimit) >> sb->s_blocksize_bits;
4856 	if (limit && buf->f_blocks > limit) {
4857 		curblock = dquot->dq_dqb.dqb_curspace >> sb->s_blocksize_bits;
4858 		buf->f_blocks = limit;
4859 		buf->f_bfree = buf->f_bavail =
4860 			(buf->f_blocks > curblock) ?
4861 			 (buf->f_blocks - curblock) : 0;
4862 	}
4863 
4864 	limit = dquot->dq_dqb.dqb_isoftlimit ?
4865 		dquot->dq_dqb.dqb_isoftlimit :
4866 		dquot->dq_dqb.dqb_ihardlimit;
4867 	if (limit && buf->f_files > limit) {
4868 		buf->f_files = limit;
4869 		buf->f_ffree =
4870 			(buf->f_files > dquot->dq_dqb.dqb_curinodes) ?
4871 			 (buf->f_files - dquot->dq_dqb.dqb_curinodes) : 0;
4872 	}
4873 
4874 	spin_unlock(&dq_data_lock);
4875 	dqput(dquot);
4876 	return 0;
4877 }
4878 #endif
4879 
4880 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
4881 {
4882 	struct super_block *sb = dentry->d_sb;
4883 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4884 	struct ext4_super_block *es = sbi->s_es;
4885 	ext4_fsblk_t overhead = 0, resv_blocks;
4886 	u64 fsid;
4887 	s64 bfree;
4888 	resv_blocks = EXT4_C2B(sbi, atomic64_read(&sbi->s_resv_clusters));
4889 
4890 	if (!test_opt(sb, MINIX_DF))
4891 		overhead = sbi->s_overhead;
4892 
4893 	buf->f_type = EXT4_SUPER_MAGIC;
4894 	buf->f_bsize = sb->s_blocksize;
4895 	buf->f_blocks = ext4_blocks_count(es) - EXT4_C2B(sbi, overhead);
4896 	bfree = percpu_counter_sum_positive(&sbi->s_freeclusters_counter) -
4897 		percpu_counter_sum_positive(&sbi->s_dirtyclusters_counter);
4898 	/* prevent underflow in case that few free space is available */
4899 	buf->f_bfree = EXT4_C2B(sbi, max_t(s64, bfree, 0));
4900 	buf->f_bavail = buf->f_bfree -
4901 			(ext4_r_blocks_count(es) + resv_blocks);
4902 	if (buf->f_bfree < (ext4_r_blocks_count(es) + resv_blocks))
4903 		buf->f_bavail = 0;
4904 	buf->f_files = le32_to_cpu(es->s_inodes_count);
4905 	buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter);
4906 	buf->f_namelen = EXT4_NAME_LEN;
4907 	fsid = le64_to_cpup((void *)es->s_uuid) ^
4908 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
4909 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
4910 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
4911 
4912 #ifdef CONFIG_QUOTA
4913 	if (ext4_test_inode_flag(dentry->d_inode, EXT4_INODE_PROJINHERIT) &&
4914 	    sb_has_quota_limits_enabled(sb, PRJQUOTA))
4915 		ext4_statfs_project(sb, EXT4_I(dentry->d_inode)->i_projid, buf);
4916 #endif
4917 	return 0;
4918 }
4919 
4920 /* Helper function for writing quotas on sync - we need to start transaction
4921  * before quota file is locked for write. Otherwise the are possible deadlocks:
4922  * Process 1                         Process 2
4923  * ext4_create()                     quota_sync()
4924  *   jbd2_journal_start()                  write_dquot()
4925  *   dquot_initialize()                         down(dqio_mutex)
4926  *     down(dqio_mutex)                    jbd2_journal_start()
4927  *
4928  */
4929 
4930 #ifdef CONFIG_QUOTA
4931 
4932 static inline struct inode *dquot_to_inode(struct dquot *dquot)
4933 {
4934 	return sb_dqopt(dquot->dq_sb)->files[dquot->dq_id.type];
4935 }
4936 
4937 static int ext4_write_dquot(struct dquot *dquot)
4938 {
4939 	int ret, err;
4940 	handle_t *handle;
4941 	struct inode *inode;
4942 
4943 	inode = dquot_to_inode(dquot);
4944 	handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
4945 				    EXT4_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
4946 	if (IS_ERR(handle))
4947 		return PTR_ERR(handle);
4948 	ret = dquot_commit(dquot);
4949 	err = ext4_journal_stop(handle);
4950 	if (!ret)
4951 		ret = err;
4952 	return ret;
4953 }
4954 
4955 static int ext4_acquire_dquot(struct dquot *dquot)
4956 {
4957 	int ret, err;
4958 	handle_t *handle;
4959 
4960 	handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
4961 				    EXT4_QUOTA_INIT_BLOCKS(dquot->dq_sb));
4962 	if (IS_ERR(handle))
4963 		return PTR_ERR(handle);
4964 	ret = dquot_acquire(dquot);
4965 	err = ext4_journal_stop(handle);
4966 	if (!ret)
4967 		ret = err;
4968 	return ret;
4969 }
4970 
4971 static int ext4_release_dquot(struct dquot *dquot)
4972 {
4973 	int ret, err;
4974 	handle_t *handle;
4975 
4976 	handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
4977 				    EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
4978 	if (IS_ERR(handle)) {
4979 		/* Release dquot anyway to avoid endless cycle in dqput() */
4980 		dquot_release(dquot);
4981 		return PTR_ERR(handle);
4982 	}
4983 	ret = dquot_release(dquot);
4984 	err = ext4_journal_stop(handle);
4985 	if (!ret)
4986 		ret = err;
4987 	return ret;
4988 }
4989 
4990 static int ext4_mark_dquot_dirty(struct dquot *dquot)
4991 {
4992 	struct super_block *sb = dquot->dq_sb;
4993 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4994 
4995 	/* Are we journaling quotas? */
4996 	if (ext4_has_feature_quota(sb) ||
4997 	    sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
4998 		dquot_mark_dquot_dirty(dquot);
4999 		return ext4_write_dquot(dquot);
5000 	} else {
5001 		return dquot_mark_dquot_dirty(dquot);
5002 	}
5003 }
5004 
5005 static int ext4_write_info(struct super_block *sb, int type)
5006 {
5007 	int ret, err;
5008 	handle_t *handle;
5009 
5010 	/* Data block + inode block */
5011 	handle = ext4_journal_start(d_inode(sb->s_root), EXT4_HT_QUOTA, 2);
5012 	if (IS_ERR(handle))
5013 		return PTR_ERR(handle);
5014 	ret = dquot_commit_info(sb, type);
5015 	err = ext4_journal_stop(handle);
5016 	if (!ret)
5017 		ret = err;
5018 	return ret;
5019 }
5020 
5021 /*
5022  * Turn on quotas during mount time - we need to find
5023  * the quota file and such...
5024  */
5025 static int ext4_quota_on_mount(struct super_block *sb, int type)
5026 {
5027 	return dquot_quota_on_mount(sb, EXT4_SB(sb)->s_qf_names[type],
5028 					EXT4_SB(sb)->s_jquota_fmt, type);
5029 }
5030 
5031 /*
5032  * Standard function to be called on quota_on
5033  */
5034 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
5035 			 struct path *path)
5036 {
5037 	int err;
5038 
5039 	if (!test_opt(sb, QUOTA))
5040 		return -EINVAL;
5041 
5042 	/* Quotafile not on the same filesystem? */
5043 	if (path->dentry->d_sb != sb)
5044 		return -EXDEV;
5045 	/* Journaling quota? */
5046 	if (EXT4_SB(sb)->s_qf_names[type]) {
5047 		/* Quotafile not in fs root? */
5048 		if (path->dentry->d_parent != sb->s_root)
5049 			ext4_msg(sb, KERN_WARNING,
5050 				"Quota file not on filesystem root. "
5051 				"Journaled quota will not work");
5052 	}
5053 
5054 	/*
5055 	 * When we journal data on quota file, we have to flush journal to see
5056 	 * all updates to the file when we bypass pagecache...
5057 	 */
5058 	if (EXT4_SB(sb)->s_journal &&
5059 	    ext4_should_journal_data(d_inode(path->dentry))) {
5060 		/*
5061 		 * We don't need to lock updates but journal_flush() could
5062 		 * otherwise be livelocked...
5063 		 */
5064 		jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
5065 		err = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
5066 		jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
5067 		if (err)
5068 			return err;
5069 	}
5070 
5071 	return dquot_quota_on(sb, type, format_id, path);
5072 }
5073 
5074 static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
5075 			     unsigned int flags)
5076 {
5077 	int err;
5078 	struct inode *qf_inode;
5079 	unsigned long qf_inums[EXT4_MAXQUOTAS] = {
5080 		le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
5081 		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum),
5082 		le32_to_cpu(EXT4_SB(sb)->s_es->s_prj_quota_inum)
5083 	};
5084 
5085 	BUG_ON(!ext4_has_feature_quota(sb));
5086 
5087 	if (!qf_inums[type])
5088 		return -EPERM;
5089 
5090 	qf_inode = ext4_iget(sb, qf_inums[type]);
5091 	if (IS_ERR(qf_inode)) {
5092 		ext4_error(sb, "Bad quota inode # %lu", qf_inums[type]);
5093 		return PTR_ERR(qf_inode);
5094 	}
5095 
5096 	/* Don't account quota for quota files to avoid recursion */
5097 	qf_inode->i_flags |= S_NOQUOTA;
5098 	err = dquot_enable(qf_inode, type, format_id, flags);
5099 	iput(qf_inode);
5100 
5101 	return err;
5102 }
5103 
5104 /* Enable usage tracking for all quota types. */
5105 static int ext4_enable_quotas(struct super_block *sb)
5106 {
5107 	int type, err = 0;
5108 	unsigned long qf_inums[EXT4_MAXQUOTAS] = {
5109 		le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
5110 		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum),
5111 		le32_to_cpu(EXT4_SB(sb)->s_es->s_prj_quota_inum)
5112 	};
5113 
5114 	sb_dqopt(sb)->flags |= DQUOT_QUOTA_SYS_FILE;
5115 	for (type = 0; type < EXT4_MAXQUOTAS; type++) {
5116 		if (qf_inums[type]) {
5117 			err = ext4_quota_enable(sb, type, QFMT_VFS_V1,
5118 						DQUOT_USAGE_ENABLED);
5119 			if (err) {
5120 				ext4_warning(sb,
5121 					"Failed to enable quota tracking "
5122 					"(type=%d, err=%d). Please run "
5123 					"e2fsck to fix.", type, err);
5124 				return err;
5125 			}
5126 		}
5127 	}
5128 	return 0;
5129 }
5130 
5131 static int ext4_quota_off(struct super_block *sb, int type)
5132 {
5133 	struct inode *inode = sb_dqopt(sb)->files[type];
5134 	handle_t *handle;
5135 
5136 	/* Force all delayed allocation blocks to be allocated.
5137 	 * Caller already holds s_umount sem */
5138 	if (test_opt(sb, DELALLOC))
5139 		sync_filesystem(sb);
5140 
5141 	if (!inode)
5142 		goto out;
5143 
5144 	/* Update modification times of quota files when userspace can
5145 	 * start looking at them */
5146 	handle = ext4_journal_start(inode, EXT4_HT_QUOTA, 1);
5147 	if (IS_ERR(handle))
5148 		goto out;
5149 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
5150 	ext4_mark_inode_dirty(handle, inode);
5151 	ext4_journal_stop(handle);
5152 
5153 out:
5154 	return dquot_quota_off(sb, type);
5155 }
5156 
5157 /* Read data from quotafile - avoid pagecache and such because we cannot afford
5158  * acquiring the locks... As quota files are never truncated and quota code
5159  * itself serializes the operations (and no one else should touch the files)
5160  * we don't have to be afraid of races */
5161 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
5162 			       size_t len, loff_t off)
5163 {
5164 	struct inode *inode = sb_dqopt(sb)->files[type];
5165 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
5166 	int offset = off & (sb->s_blocksize - 1);
5167 	int tocopy;
5168 	size_t toread;
5169 	struct buffer_head *bh;
5170 	loff_t i_size = i_size_read(inode);
5171 
5172 	if (off > i_size)
5173 		return 0;
5174 	if (off+len > i_size)
5175 		len = i_size-off;
5176 	toread = len;
5177 	while (toread > 0) {
5178 		tocopy = sb->s_blocksize - offset < toread ?
5179 				sb->s_blocksize - offset : toread;
5180 		bh = ext4_bread(NULL, inode, blk, 0);
5181 		if (IS_ERR(bh))
5182 			return PTR_ERR(bh);
5183 		if (!bh)	/* A hole? */
5184 			memset(data, 0, tocopy);
5185 		else
5186 			memcpy(data, bh->b_data+offset, tocopy);
5187 		brelse(bh);
5188 		offset = 0;
5189 		toread -= tocopy;
5190 		data += tocopy;
5191 		blk++;
5192 	}
5193 	return len;
5194 }
5195 
5196 /* Write to quotafile (we know the transaction is already started and has
5197  * enough credits) */
5198 static ssize_t ext4_quota_write(struct super_block *sb, int type,
5199 				const char *data, size_t len, loff_t off)
5200 {
5201 	struct inode *inode = sb_dqopt(sb)->files[type];
5202 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
5203 	int err, offset = off & (sb->s_blocksize - 1);
5204 	int retries = 0;
5205 	struct buffer_head *bh;
5206 	handle_t *handle = journal_current_handle();
5207 
5208 	if (EXT4_SB(sb)->s_journal && !handle) {
5209 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
5210 			" cancelled because transaction is not started",
5211 			(unsigned long long)off, (unsigned long long)len);
5212 		return -EIO;
5213 	}
5214 	/*
5215 	 * Since we account only one data block in transaction credits,
5216 	 * then it is impossible to cross a block boundary.
5217 	 */
5218 	if (sb->s_blocksize - offset < len) {
5219 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
5220 			" cancelled because not block aligned",
5221 			(unsigned long long)off, (unsigned long long)len);
5222 		return -EIO;
5223 	}
5224 
5225 	do {
5226 		bh = ext4_bread(handle, inode, blk,
5227 				EXT4_GET_BLOCKS_CREATE |
5228 				EXT4_GET_BLOCKS_METADATA_NOFAIL);
5229 	} while (IS_ERR(bh) && (PTR_ERR(bh) == -ENOSPC) &&
5230 		 ext4_should_retry_alloc(inode->i_sb, &retries));
5231 	if (IS_ERR(bh))
5232 		return PTR_ERR(bh);
5233 	if (!bh)
5234 		goto out;
5235 	BUFFER_TRACE(bh, "get write access");
5236 	err = ext4_journal_get_write_access(handle, bh);
5237 	if (err) {
5238 		brelse(bh);
5239 		return err;
5240 	}
5241 	lock_buffer(bh);
5242 	memcpy(bh->b_data+offset, data, len);
5243 	flush_dcache_page(bh->b_page);
5244 	unlock_buffer(bh);
5245 	err = ext4_handle_dirty_metadata(handle, NULL, bh);
5246 	brelse(bh);
5247 out:
5248 	if (inode->i_size < off + len) {
5249 		i_size_write(inode, off + len);
5250 		EXT4_I(inode)->i_disksize = inode->i_size;
5251 		ext4_mark_inode_dirty(handle, inode);
5252 	}
5253 	return len;
5254 }
5255 
5256 #endif
5257 
5258 static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
5259 		       const char *dev_name, void *data)
5260 {
5261 	return mount_bdev(fs_type, flags, dev_name, data, ext4_fill_super);
5262 }
5263 
5264 #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT2)
5265 static inline void register_as_ext2(void)
5266 {
5267 	int err = register_filesystem(&ext2_fs_type);
5268 	if (err)
5269 		printk(KERN_WARNING
5270 		       "EXT4-fs: Unable to register as ext2 (%d)\n", err);
5271 }
5272 
5273 static inline void unregister_as_ext2(void)
5274 {
5275 	unregister_filesystem(&ext2_fs_type);
5276 }
5277 
5278 static inline int ext2_feature_set_ok(struct super_block *sb)
5279 {
5280 	if (ext4_has_unknown_ext2_incompat_features(sb))
5281 		return 0;
5282 	if (sb->s_flags & MS_RDONLY)
5283 		return 1;
5284 	if (ext4_has_unknown_ext2_ro_compat_features(sb))
5285 		return 0;
5286 	return 1;
5287 }
5288 #else
5289 static inline void register_as_ext2(void) { }
5290 static inline void unregister_as_ext2(void) { }
5291 static inline int ext2_feature_set_ok(struct super_block *sb) { return 0; }
5292 #endif
5293 
5294 static inline void register_as_ext3(void)
5295 {
5296 	int err = register_filesystem(&ext3_fs_type);
5297 	if (err)
5298 		printk(KERN_WARNING
5299 		       "EXT4-fs: Unable to register as ext3 (%d)\n", err);
5300 }
5301 
5302 static inline void unregister_as_ext3(void)
5303 {
5304 	unregister_filesystem(&ext3_fs_type);
5305 }
5306 
5307 static inline int ext3_feature_set_ok(struct super_block *sb)
5308 {
5309 	if (ext4_has_unknown_ext3_incompat_features(sb))
5310 		return 0;
5311 	if (!ext4_has_feature_journal(sb))
5312 		return 0;
5313 	if (sb->s_flags & MS_RDONLY)
5314 		return 1;
5315 	if (ext4_has_unknown_ext3_ro_compat_features(sb))
5316 		return 0;
5317 	return 1;
5318 }
5319 
5320 static struct file_system_type ext4_fs_type = {
5321 	.owner		= THIS_MODULE,
5322 	.name		= "ext4",
5323 	.mount		= ext4_mount,
5324 	.kill_sb	= kill_block_super,
5325 	.fs_flags	= FS_REQUIRES_DEV,
5326 };
5327 MODULE_ALIAS_FS("ext4");
5328 
5329 /* Shared across all ext4 file systems */
5330 wait_queue_head_t ext4__ioend_wq[EXT4_WQ_HASH_SZ];
5331 
5332 static int __init ext4_init_fs(void)
5333 {
5334 	int i, err;
5335 
5336 	ratelimit_state_init(&ext4_mount_msg_ratelimit, 30 * HZ, 64);
5337 	ext4_li_info = NULL;
5338 	mutex_init(&ext4_li_mtx);
5339 
5340 	/* Build-time check for flags consistency */
5341 	ext4_check_flag_values();
5342 
5343 	for (i = 0; i < EXT4_WQ_HASH_SZ; i++)
5344 		init_waitqueue_head(&ext4__ioend_wq[i]);
5345 
5346 	err = ext4_init_es();
5347 	if (err)
5348 		return err;
5349 
5350 	err = ext4_init_pageio();
5351 	if (err)
5352 		goto out5;
5353 
5354 	err = ext4_init_system_zone();
5355 	if (err)
5356 		goto out4;
5357 
5358 	err = ext4_init_sysfs();
5359 	if (err)
5360 		goto out3;
5361 
5362 	err = ext4_init_mballoc();
5363 	if (err)
5364 		goto out2;
5365 	err = init_inodecache();
5366 	if (err)
5367 		goto out1;
5368 	register_as_ext3();
5369 	register_as_ext2();
5370 	err = register_filesystem(&ext4_fs_type);
5371 	if (err)
5372 		goto out;
5373 
5374 	return 0;
5375 out:
5376 	unregister_as_ext2();
5377 	unregister_as_ext3();
5378 	destroy_inodecache();
5379 out1:
5380 	ext4_exit_mballoc();
5381 out2:
5382 	ext4_exit_sysfs();
5383 out3:
5384 	ext4_exit_system_zone();
5385 out4:
5386 	ext4_exit_pageio();
5387 out5:
5388 	ext4_exit_es();
5389 
5390 	return err;
5391 }
5392 
5393 static void __exit ext4_exit_fs(void)
5394 {
5395 	ext4_exit_crypto();
5396 	ext4_destroy_lazyinit_thread();
5397 	unregister_as_ext2();
5398 	unregister_as_ext3();
5399 	unregister_filesystem(&ext4_fs_type);
5400 	destroy_inodecache();
5401 	ext4_exit_mballoc();
5402 	ext4_exit_sysfs();
5403 	ext4_exit_system_zone();
5404 	ext4_exit_pageio();
5405 	ext4_exit_es();
5406 }
5407 
5408 MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
5409 MODULE_DESCRIPTION("Fourth Extended Filesystem");
5410 MODULE_LICENSE("GPL");
5411 module_init(ext4_init_fs)
5412 module_exit(ext4_exit_fs)
5413