xref: /linux/fs/ext4/super.c (revision 5e4e38446a62a4f50d77b0dd11d4b379dee08988)
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 };
1133 
1134 static const struct quotactl_ops ext4_qctl_operations = {
1135 	.quota_on	= ext4_quota_on,
1136 	.quota_off	= ext4_quota_off,
1137 	.quota_sync	= dquot_quota_sync,
1138 	.get_state	= dquot_get_state,
1139 	.set_info	= dquot_set_dqinfo,
1140 	.get_dqblk	= dquot_get_dqblk,
1141 	.set_dqblk	= dquot_set_dqblk
1142 };
1143 #endif
1144 
1145 static const struct super_operations ext4_sops = {
1146 	.alloc_inode	= ext4_alloc_inode,
1147 	.destroy_inode	= ext4_destroy_inode,
1148 	.write_inode	= ext4_write_inode,
1149 	.dirty_inode	= ext4_dirty_inode,
1150 	.drop_inode	= ext4_drop_inode,
1151 	.evict_inode	= ext4_evict_inode,
1152 	.put_super	= ext4_put_super,
1153 	.sync_fs	= ext4_sync_fs,
1154 	.freeze_fs	= ext4_freeze,
1155 	.unfreeze_fs	= ext4_unfreeze,
1156 	.statfs		= ext4_statfs,
1157 	.remount_fs	= ext4_remount,
1158 	.show_options	= ext4_show_options,
1159 #ifdef CONFIG_QUOTA
1160 	.quota_read	= ext4_quota_read,
1161 	.quota_write	= ext4_quota_write,
1162 	.get_dquots	= ext4_get_dquots,
1163 #endif
1164 	.bdev_try_to_free_page = bdev_try_to_free_page,
1165 };
1166 
1167 static const struct export_operations ext4_export_ops = {
1168 	.fh_to_dentry = ext4_fh_to_dentry,
1169 	.fh_to_parent = ext4_fh_to_parent,
1170 	.get_parent = ext4_get_parent,
1171 };
1172 
1173 enum {
1174 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
1175 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
1176 	Opt_nouid32, Opt_debug, Opt_removed,
1177 	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
1178 	Opt_auto_da_alloc, Opt_noauto_da_alloc, Opt_noload,
1179 	Opt_commit, Opt_min_batch_time, Opt_max_batch_time, Opt_journal_dev,
1180 	Opt_journal_path, Opt_journal_checksum, Opt_journal_async_commit,
1181 	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
1182 	Opt_data_err_abort, Opt_data_err_ignore, Opt_test_dummy_encryption,
1183 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
1184 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
1185 	Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err,
1186 	Opt_usrquota, Opt_grpquota, Opt_i_version, Opt_dax,
1187 	Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_mblk_io_submit,
1188 	Opt_lazytime, Opt_nolazytime,
1189 	Opt_nomblk_io_submit, Opt_block_validity, Opt_noblock_validity,
1190 	Opt_inode_readahead_blks, Opt_journal_ioprio,
1191 	Opt_dioread_nolock, Opt_dioread_lock,
1192 	Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
1193 	Opt_max_dir_size_kb, Opt_nojournal_checksum,
1194 };
1195 
1196 static const match_table_t tokens = {
1197 	{Opt_bsd_df, "bsddf"},
1198 	{Opt_minix_df, "minixdf"},
1199 	{Opt_grpid, "grpid"},
1200 	{Opt_grpid, "bsdgroups"},
1201 	{Opt_nogrpid, "nogrpid"},
1202 	{Opt_nogrpid, "sysvgroups"},
1203 	{Opt_resgid, "resgid=%u"},
1204 	{Opt_resuid, "resuid=%u"},
1205 	{Opt_sb, "sb=%u"},
1206 	{Opt_err_cont, "errors=continue"},
1207 	{Opt_err_panic, "errors=panic"},
1208 	{Opt_err_ro, "errors=remount-ro"},
1209 	{Opt_nouid32, "nouid32"},
1210 	{Opt_debug, "debug"},
1211 	{Opt_removed, "oldalloc"},
1212 	{Opt_removed, "orlov"},
1213 	{Opt_user_xattr, "user_xattr"},
1214 	{Opt_nouser_xattr, "nouser_xattr"},
1215 	{Opt_acl, "acl"},
1216 	{Opt_noacl, "noacl"},
1217 	{Opt_noload, "norecovery"},
1218 	{Opt_noload, "noload"},
1219 	{Opt_removed, "nobh"},
1220 	{Opt_removed, "bh"},
1221 	{Opt_commit, "commit=%u"},
1222 	{Opt_min_batch_time, "min_batch_time=%u"},
1223 	{Opt_max_batch_time, "max_batch_time=%u"},
1224 	{Opt_journal_dev, "journal_dev=%u"},
1225 	{Opt_journal_path, "journal_path=%s"},
1226 	{Opt_journal_checksum, "journal_checksum"},
1227 	{Opt_nojournal_checksum, "nojournal_checksum"},
1228 	{Opt_journal_async_commit, "journal_async_commit"},
1229 	{Opt_abort, "abort"},
1230 	{Opt_data_journal, "data=journal"},
1231 	{Opt_data_ordered, "data=ordered"},
1232 	{Opt_data_writeback, "data=writeback"},
1233 	{Opt_data_err_abort, "data_err=abort"},
1234 	{Opt_data_err_ignore, "data_err=ignore"},
1235 	{Opt_offusrjquota, "usrjquota="},
1236 	{Opt_usrjquota, "usrjquota=%s"},
1237 	{Opt_offgrpjquota, "grpjquota="},
1238 	{Opt_grpjquota, "grpjquota=%s"},
1239 	{Opt_jqfmt_vfsold, "jqfmt=vfsold"},
1240 	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
1241 	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
1242 	{Opt_grpquota, "grpquota"},
1243 	{Opt_noquota, "noquota"},
1244 	{Opt_quota, "quota"},
1245 	{Opt_usrquota, "usrquota"},
1246 	{Opt_barrier, "barrier=%u"},
1247 	{Opt_barrier, "barrier"},
1248 	{Opt_nobarrier, "nobarrier"},
1249 	{Opt_i_version, "i_version"},
1250 	{Opt_dax, "dax"},
1251 	{Opt_stripe, "stripe=%u"},
1252 	{Opt_delalloc, "delalloc"},
1253 	{Opt_lazytime, "lazytime"},
1254 	{Opt_nolazytime, "nolazytime"},
1255 	{Opt_nodelalloc, "nodelalloc"},
1256 	{Opt_removed, "mblk_io_submit"},
1257 	{Opt_removed, "nomblk_io_submit"},
1258 	{Opt_block_validity, "block_validity"},
1259 	{Opt_noblock_validity, "noblock_validity"},
1260 	{Opt_inode_readahead_blks, "inode_readahead_blks=%u"},
1261 	{Opt_journal_ioprio, "journal_ioprio=%u"},
1262 	{Opt_auto_da_alloc, "auto_da_alloc=%u"},
1263 	{Opt_auto_da_alloc, "auto_da_alloc"},
1264 	{Opt_noauto_da_alloc, "noauto_da_alloc"},
1265 	{Opt_dioread_nolock, "dioread_nolock"},
1266 	{Opt_dioread_lock, "dioread_lock"},
1267 	{Opt_discard, "discard"},
1268 	{Opt_nodiscard, "nodiscard"},
1269 	{Opt_init_itable, "init_itable=%u"},
1270 	{Opt_init_itable, "init_itable"},
1271 	{Opt_noinit_itable, "noinit_itable"},
1272 	{Opt_max_dir_size_kb, "max_dir_size_kb=%u"},
1273 	{Opt_test_dummy_encryption, "test_dummy_encryption"},
1274 	{Opt_removed, "check=none"},	/* mount option from ext2/3 */
1275 	{Opt_removed, "nocheck"},	/* mount option from ext2/3 */
1276 	{Opt_removed, "reservation"},	/* mount option from ext2/3 */
1277 	{Opt_removed, "noreservation"}, /* mount option from ext2/3 */
1278 	{Opt_removed, "journal=%u"},	/* mount option from ext2/3 */
1279 	{Opt_err, NULL},
1280 };
1281 
1282 static ext4_fsblk_t get_sb_block(void **data)
1283 {
1284 	ext4_fsblk_t	sb_block;
1285 	char		*options = (char *) *data;
1286 
1287 	if (!options || strncmp(options, "sb=", 3) != 0)
1288 		return 1;	/* Default location */
1289 
1290 	options += 3;
1291 	/* TODO: use simple_strtoll with >32bit ext4 */
1292 	sb_block = simple_strtoul(options, &options, 0);
1293 	if (*options && *options != ',') {
1294 		printk(KERN_ERR "EXT4-fs: Invalid sb specification: %s\n",
1295 		       (char *) *data);
1296 		return 1;
1297 	}
1298 	if (*options == ',')
1299 		options++;
1300 	*data = (void *) options;
1301 
1302 	return sb_block;
1303 }
1304 
1305 #define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))
1306 static char deprecated_msg[] = "Mount option \"%s\" will be removed by %s\n"
1307 	"Contact linux-ext4@vger.kernel.org if you think we should keep it.\n";
1308 
1309 #ifdef CONFIG_QUOTA
1310 static int set_qf_name(struct super_block *sb, int qtype, substring_t *args)
1311 {
1312 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1313 	char *qname;
1314 	int ret = -1;
1315 
1316 	if (sb_any_quota_loaded(sb) &&
1317 		!sbi->s_qf_names[qtype]) {
1318 		ext4_msg(sb, KERN_ERR,
1319 			"Cannot change journaled "
1320 			"quota options when quota turned on");
1321 		return -1;
1322 	}
1323 	if (ext4_has_feature_quota(sb)) {
1324 		ext4_msg(sb, KERN_ERR, "Cannot set journaled quota options "
1325 			 "when QUOTA feature is enabled");
1326 		return -1;
1327 	}
1328 	qname = match_strdup(args);
1329 	if (!qname) {
1330 		ext4_msg(sb, KERN_ERR,
1331 			"Not enough memory for storing quotafile name");
1332 		return -1;
1333 	}
1334 	if (sbi->s_qf_names[qtype]) {
1335 		if (strcmp(sbi->s_qf_names[qtype], qname) == 0)
1336 			ret = 1;
1337 		else
1338 			ext4_msg(sb, KERN_ERR,
1339 				 "%s quota file already specified",
1340 				 QTYPE2NAME(qtype));
1341 		goto errout;
1342 	}
1343 	if (strchr(qname, '/')) {
1344 		ext4_msg(sb, KERN_ERR,
1345 			"quotafile must be on filesystem root");
1346 		goto errout;
1347 	}
1348 	sbi->s_qf_names[qtype] = qname;
1349 	set_opt(sb, QUOTA);
1350 	return 1;
1351 errout:
1352 	kfree(qname);
1353 	return ret;
1354 }
1355 
1356 static int clear_qf_name(struct super_block *sb, int qtype)
1357 {
1358 
1359 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1360 
1361 	if (sb_any_quota_loaded(sb) &&
1362 		sbi->s_qf_names[qtype]) {
1363 		ext4_msg(sb, KERN_ERR, "Cannot change journaled quota options"
1364 			" when quota turned on");
1365 		return -1;
1366 	}
1367 	kfree(sbi->s_qf_names[qtype]);
1368 	sbi->s_qf_names[qtype] = NULL;
1369 	return 1;
1370 }
1371 #endif
1372 
1373 #define MOPT_SET	0x0001
1374 #define MOPT_CLEAR	0x0002
1375 #define MOPT_NOSUPPORT	0x0004
1376 #define MOPT_EXPLICIT	0x0008
1377 #define MOPT_CLEAR_ERR	0x0010
1378 #define MOPT_GTE0	0x0020
1379 #ifdef CONFIG_QUOTA
1380 #define MOPT_Q		0
1381 #define MOPT_QFMT	0x0040
1382 #else
1383 #define MOPT_Q		MOPT_NOSUPPORT
1384 #define MOPT_QFMT	MOPT_NOSUPPORT
1385 #endif
1386 #define MOPT_DATAJ	0x0080
1387 #define MOPT_NO_EXT2	0x0100
1388 #define MOPT_NO_EXT3	0x0200
1389 #define MOPT_EXT4_ONLY	(MOPT_NO_EXT2 | MOPT_NO_EXT3)
1390 #define MOPT_STRING	0x0400
1391 
1392 static const struct mount_opts {
1393 	int	token;
1394 	int	mount_opt;
1395 	int	flags;
1396 } ext4_mount_opts[] = {
1397 	{Opt_minix_df, EXT4_MOUNT_MINIX_DF, MOPT_SET},
1398 	{Opt_bsd_df, EXT4_MOUNT_MINIX_DF, MOPT_CLEAR},
1399 	{Opt_grpid, EXT4_MOUNT_GRPID, MOPT_SET},
1400 	{Opt_nogrpid, EXT4_MOUNT_GRPID, MOPT_CLEAR},
1401 	{Opt_block_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_SET},
1402 	{Opt_noblock_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_CLEAR},
1403 	{Opt_dioread_nolock, EXT4_MOUNT_DIOREAD_NOLOCK,
1404 	 MOPT_EXT4_ONLY | MOPT_SET},
1405 	{Opt_dioread_lock, EXT4_MOUNT_DIOREAD_NOLOCK,
1406 	 MOPT_EXT4_ONLY | MOPT_CLEAR},
1407 	{Opt_discard, EXT4_MOUNT_DISCARD, MOPT_SET},
1408 	{Opt_nodiscard, EXT4_MOUNT_DISCARD, MOPT_CLEAR},
1409 	{Opt_delalloc, EXT4_MOUNT_DELALLOC,
1410 	 MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
1411 	{Opt_nodelalloc, EXT4_MOUNT_DELALLOC,
1412 	 MOPT_EXT4_ONLY | MOPT_CLEAR},
1413 	{Opt_nojournal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,
1414 	 MOPT_EXT4_ONLY | MOPT_CLEAR},
1415 	{Opt_journal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,
1416 	 MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
1417 	{Opt_journal_async_commit, (EXT4_MOUNT_JOURNAL_ASYNC_COMMIT |
1418 				    EXT4_MOUNT_JOURNAL_CHECKSUM),
1419 	 MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
1420 	{Opt_noload, EXT4_MOUNT_NOLOAD, MOPT_NO_EXT2 | MOPT_SET},
1421 	{Opt_err_panic, EXT4_MOUNT_ERRORS_PANIC, MOPT_SET | MOPT_CLEAR_ERR},
1422 	{Opt_err_ro, EXT4_MOUNT_ERRORS_RO, MOPT_SET | MOPT_CLEAR_ERR},
1423 	{Opt_err_cont, EXT4_MOUNT_ERRORS_CONT, MOPT_SET | MOPT_CLEAR_ERR},
1424 	{Opt_data_err_abort, EXT4_MOUNT_DATA_ERR_ABORT,
1425 	 MOPT_NO_EXT2},
1426 	{Opt_data_err_ignore, EXT4_MOUNT_DATA_ERR_ABORT,
1427 	 MOPT_NO_EXT2},
1428 	{Opt_barrier, EXT4_MOUNT_BARRIER, MOPT_SET},
1429 	{Opt_nobarrier, EXT4_MOUNT_BARRIER, MOPT_CLEAR},
1430 	{Opt_noauto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_SET},
1431 	{Opt_auto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_CLEAR},
1432 	{Opt_noinit_itable, EXT4_MOUNT_INIT_INODE_TABLE, MOPT_CLEAR},
1433 	{Opt_commit, 0, MOPT_GTE0},
1434 	{Opt_max_batch_time, 0, MOPT_GTE0},
1435 	{Opt_min_batch_time, 0, MOPT_GTE0},
1436 	{Opt_inode_readahead_blks, 0, MOPT_GTE0},
1437 	{Opt_init_itable, 0, MOPT_GTE0},
1438 	{Opt_dax, EXT4_MOUNT_DAX, MOPT_SET},
1439 	{Opt_stripe, 0, MOPT_GTE0},
1440 	{Opt_resuid, 0, MOPT_GTE0},
1441 	{Opt_resgid, 0, MOPT_GTE0},
1442 	{Opt_journal_dev, 0, MOPT_NO_EXT2 | MOPT_GTE0},
1443 	{Opt_journal_path, 0, MOPT_NO_EXT2 | MOPT_STRING},
1444 	{Opt_journal_ioprio, 0, MOPT_NO_EXT2 | MOPT_GTE0},
1445 	{Opt_data_journal, EXT4_MOUNT_JOURNAL_DATA, MOPT_NO_EXT2 | MOPT_DATAJ},
1446 	{Opt_data_ordered, EXT4_MOUNT_ORDERED_DATA, MOPT_NO_EXT2 | MOPT_DATAJ},
1447 	{Opt_data_writeback, EXT4_MOUNT_WRITEBACK_DATA,
1448 	 MOPT_NO_EXT2 | MOPT_DATAJ},
1449 	{Opt_user_xattr, EXT4_MOUNT_XATTR_USER, MOPT_SET},
1450 	{Opt_nouser_xattr, EXT4_MOUNT_XATTR_USER, MOPT_CLEAR},
1451 #ifdef CONFIG_EXT4_FS_POSIX_ACL
1452 	{Opt_acl, EXT4_MOUNT_POSIX_ACL, MOPT_SET},
1453 	{Opt_noacl, EXT4_MOUNT_POSIX_ACL, MOPT_CLEAR},
1454 #else
1455 	{Opt_acl, 0, MOPT_NOSUPPORT},
1456 	{Opt_noacl, 0, MOPT_NOSUPPORT},
1457 #endif
1458 	{Opt_nouid32, EXT4_MOUNT_NO_UID32, MOPT_SET},
1459 	{Opt_debug, EXT4_MOUNT_DEBUG, MOPT_SET},
1460 	{Opt_quota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA, MOPT_SET | MOPT_Q},
1461 	{Opt_usrquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA,
1462 							MOPT_SET | MOPT_Q},
1463 	{Opt_grpquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_GRPQUOTA,
1464 							MOPT_SET | MOPT_Q},
1465 	{Opt_noquota, (EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA |
1466 		       EXT4_MOUNT_GRPQUOTA), MOPT_CLEAR | MOPT_Q},
1467 	{Opt_usrjquota, 0, MOPT_Q},
1468 	{Opt_grpjquota, 0, MOPT_Q},
1469 	{Opt_offusrjquota, 0, MOPT_Q},
1470 	{Opt_offgrpjquota, 0, MOPT_Q},
1471 	{Opt_jqfmt_vfsold, QFMT_VFS_OLD, MOPT_QFMT},
1472 	{Opt_jqfmt_vfsv0, QFMT_VFS_V0, MOPT_QFMT},
1473 	{Opt_jqfmt_vfsv1, QFMT_VFS_V1, MOPT_QFMT},
1474 	{Opt_max_dir_size_kb, 0, MOPT_GTE0},
1475 	{Opt_test_dummy_encryption, 0, MOPT_GTE0},
1476 	{Opt_err, 0, 0}
1477 };
1478 
1479 static int handle_mount_opt(struct super_block *sb, char *opt, int token,
1480 			    substring_t *args, unsigned long *journal_devnum,
1481 			    unsigned int *journal_ioprio, int is_remount)
1482 {
1483 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1484 	const struct mount_opts *m;
1485 	kuid_t uid;
1486 	kgid_t gid;
1487 	int arg = 0;
1488 
1489 #ifdef CONFIG_QUOTA
1490 	if (token == Opt_usrjquota)
1491 		return set_qf_name(sb, USRQUOTA, &args[0]);
1492 	else if (token == Opt_grpjquota)
1493 		return set_qf_name(sb, GRPQUOTA, &args[0]);
1494 	else if (token == Opt_offusrjquota)
1495 		return clear_qf_name(sb, USRQUOTA);
1496 	else if (token == Opt_offgrpjquota)
1497 		return clear_qf_name(sb, GRPQUOTA);
1498 #endif
1499 	switch (token) {
1500 	case Opt_noacl:
1501 	case Opt_nouser_xattr:
1502 		ext4_msg(sb, KERN_WARNING, deprecated_msg, opt, "3.5");
1503 		break;
1504 	case Opt_sb:
1505 		return 1;	/* handled by get_sb_block() */
1506 	case Opt_removed:
1507 		ext4_msg(sb, KERN_WARNING, "Ignoring removed %s option", opt);
1508 		return 1;
1509 	case Opt_abort:
1510 		sbi->s_mount_flags |= EXT4_MF_FS_ABORTED;
1511 		return 1;
1512 	case Opt_i_version:
1513 		sb->s_flags |= MS_I_VERSION;
1514 		return 1;
1515 	case Opt_lazytime:
1516 		sb->s_flags |= MS_LAZYTIME;
1517 		return 1;
1518 	case Opt_nolazytime:
1519 		sb->s_flags &= ~MS_LAZYTIME;
1520 		return 1;
1521 	}
1522 
1523 	for (m = ext4_mount_opts; m->token != Opt_err; m++)
1524 		if (token == m->token)
1525 			break;
1526 
1527 	if (m->token == Opt_err) {
1528 		ext4_msg(sb, KERN_ERR, "Unrecognized mount option \"%s\" "
1529 			 "or missing value", opt);
1530 		return -1;
1531 	}
1532 
1533 	if ((m->flags & MOPT_NO_EXT2) && IS_EXT2_SB(sb)) {
1534 		ext4_msg(sb, KERN_ERR,
1535 			 "Mount option \"%s\" incompatible with ext2", opt);
1536 		return -1;
1537 	}
1538 	if ((m->flags & MOPT_NO_EXT3) && IS_EXT3_SB(sb)) {
1539 		ext4_msg(sb, KERN_ERR,
1540 			 "Mount option \"%s\" incompatible with ext3", opt);
1541 		return -1;
1542 	}
1543 
1544 	if (args->from && !(m->flags & MOPT_STRING) && match_int(args, &arg))
1545 		return -1;
1546 	if (args->from && (m->flags & MOPT_GTE0) && (arg < 0))
1547 		return -1;
1548 	if (m->flags & MOPT_EXPLICIT) {
1549 		if (m->mount_opt & EXT4_MOUNT_DELALLOC) {
1550 			set_opt2(sb, EXPLICIT_DELALLOC);
1551 		} else if (m->mount_opt & EXT4_MOUNT_JOURNAL_CHECKSUM) {
1552 			set_opt2(sb, EXPLICIT_JOURNAL_CHECKSUM);
1553 		} else
1554 			return -1;
1555 	}
1556 	if (m->flags & MOPT_CLEAR_ERR)
1557 		clear_opt(sb, ERRORS_MASK);
1558 	if (token == Opt_noquota && sb_any_quota_loaded(sb)) {
1559 		ext4_msg(sb, KERN_ERR, "Cannot change quota "
1560 			 "options when quota turned on");
1561 		return -1;
1562 	}
1563 
1564 	if (m->flags & MOPT_NOSUPPORT) {
1565 		ext4_msg(sb, KERN_ERR, "%s option not supported", opt);
1566 	} else if (token == Opt_commit) {
1567 		if (arg == 0)
1568 			arg = JBD2_DEFAULT_MAX_COMMIT_AGE;
1569 		sbi->s_commit_interval = HZ * arg;
1570 	} else if (token == Opt_max_batch_time) {
1571 		sbi->s_max_batch_time = arg;
1572 	} else if (token == Opt_min_batch_time) {
1573 		sbi->s_min_batch_time = arg;
1574 	} else if (token == Opt_inode_readahead_blks) {
1575 		if (arg && (arg > (1 << 30) || !is_power_of_2(arg))) {
1576 			ext4_msg(sb, KERN_ERR,
1577 				 "EXT4-fs: inode_readahead_blks must be "
1578 				 "0 or a power of 2 smaller than 2^31");
1579 			return -1;
1580 		}
1581 		sbi->s_inode_readahead_blks = arg;
1582 	} else if (token == Opt_init_itable) {
1583 		set_opt(sb, INIT_INODE_TABLE);
1584 		if (!args->from)
1585 			arg = EXT4_DEF_LI_WAIT_MULT;
1586 		sbi->s_li_wait_mult = arg;
1587 	} else if (token == Opt_max_dir_size_kb) {
1588 		sbi->s_max_dir_size_kb = arg;
1589 	} else if (token == Opt_stripe) {
1590 		sbi->s_stripe = arg;
1591 	} else if (token == Opt_resuid) {
1592 		uid = make_kuid(current_user_ns(), arg);
1593 		if (!uid_valid(uid)) {
1594 			ext4_msg(sb, KERN_ERR, "Invalid uid value %d", arg);
1595 			return -1;
1596 		}
1597 		sbi->s_resuid = uid;
1598 	} else if (token == Opt_resgid) {
1599 		gid = make_kgid(current_user_ns(), arg);
1600 		if (!gid_valid(gid)) {
1601 			ext4_msg(sb, KERN_ERR, "Invalid gid value %d", arg);
1602 			return -1;
1603 		}
1604 		sbi->s_resgid = gid;
1605 	} else if (token == Opt_journal_dev) {
1606 		if (is_remount) {
1607 			ext4_msg(sb, KERN_ERR,
1608 				 "Cannot specify journal on remount");
1609 			return -1;
1610 		}
1611 		*journal_devnum = arg;
1612 	} else if (token == Opt_journal_path) {
1613 		char *journal_path;
1614 		struct inode *journal_inode;
1615 		struct path path;
1616 		int error;
1617 
1618 		if (is_remount) {
1619 			ext4_msg(sb, KERN_ERR,
1620 				 "Cannot specify journal on remount");
1621 			return -1;
1622 		}
1623 		journal_path = match_strdup(&args[0]);
1624 		if (!journal_path) {
1625 			ext4_msg(sb, KERN_ERR, "error: could not dup "
1626 				"journal device string");
1627 			return -1;
1628 		}
1629 
1630 		error = kern_path(journal_path, LOOKUP_FOLLOW, &path);
1631 		if (error) {
1632 			ext4_msg(sb, KERN_ERR, "error: could not find "
1633 				"journal device path: error %d", error);
1634 			kfree(journal_path);
1635 			return -1;
1636 		}
1637 
1638 		journal_inode = d_inode(path.dentry);
1639 		if (!S_ISBLK(journal_inode->i_mode)) {
1640 			ext4_msg(sb, KERN_ERR, "error: journal path %s "
1641 				"is not a block device", journal_path);
1642 			path_put(&path);
1643 			kfree(journal_path);
1644 			return -1;
1645 		}
1646 
1647 		*journal_devnum = new_encode_dev(journal_inode->i_rdev);
1648 		path_put(&path);
1649 		kfree(journal_path);
1650 	} else if (token == Opt_journal_ioprio) {
1651 		if (arg > 7) {
1652 			ext4_msg(sb, KERN_ERR, "Invalid journal IO priority"
1653 				 " (must be 0-7)");
1654 			return -1;
1655 		}
1656 		*journal_ioprio =
1657 			IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, arg);
1658 	} else if (token == Opt_test_dummy_encryption) {
1659 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1660 		sbi->s_mount_flags |= EXT4_MF_TEST_DUMMY_ENCRYPTION;
1661 		ext4_msg(sb, KERN_WARNING,
1662 			 "Test dummy encryption mode enabled");
1663 #else
1664 		ext4_msg(sb, KERN_WARNING,
1665 			 "Test dummy encryption mount option ignored");
1666 #endif
1667 	} else if (m->flags & MOPT_DATAJ) {
1668 		if (is_remount) {
1669 			if (!sbi->s_journal)
1670 				ext4_msg(sb, KERN_WARNING, "Remounting file system with no journal so ignoring journalled data option");
1671 			else if (test_opt(sb, DATA_FLAGS) != m->mount_opt) {
1672 				ext4_msg(sb, KERN_ERR,
1673 					 "Cannot change data mode on remount");
1674 				return -1;
1675 			}
1676 		} else {
1677 			clear_opt(sb, DATA_FLAGS);
1678 			sbi->s_mount_opt |= m->mount_opt;
1679 		}
1680 #ifdef CONFIG_QUOTA
1681 	} else if (m->flags & MOPT_QFMT) {
1682 		if (sb_any_quota_loaded(sb) &&
1683 		    sbi->s_jquota_fmt != m->mount_opt) {
1684 			ext4_msg(sb, KERN_ERR, "Cannot change journaled "
1685 				 "quota options when quota turned on");
1686 			return -1;
1687 		}
1688 		if (ext4_has_feature_quota(sb)) {
1689 			ext4_msg(sb, KERN_ERR,
1690 				 "Cannot set journaled quota options "
1691 				 "when QUOTA feature is enabled");
1692 			return -1;
1693 		}
1694 		sbi->s_jquota_fmt = m->mount_opt;
1695 #endif
1696 	} else if (token == Opt_dax) {
1697 #ifdef CONFIG_FS_DAX
1698 		ext4_msg(sb, KERN_WARNING,
1699 		"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
1700 			sbi->s_mount_opt |= m->mount_opt;
1701 #else
1702 		ext4_msg(sb, KERN_INFO, "dax option not supported");
1703 		return -1;
1704 #endif
1705 	} else if (token == Opt_data_err_abort) {
1706 		sbi->s_mount_opt |= m->mount_opt;
1707 	} else if (token == Opt_data_err_ignore) {
1708 		sbi->s_mount_opt &= ~m->mount_opt;
1709 	} else {
1710 		if (!args->from)
1711 			arg = 1;
1712 		if (m->flags & MOPT_CLEAR)
1713 			arg = !arg;
1714 		else if (unlikely(!(m->flags & MOPT_SET))) {
1715 			ext4_msg(sb, KERN_WARNING,
1716 				 "buggy handling of option %s", opt);
1717 			WARN_ON(1);
1718 			return -1;
1719 		}
1720 		if (arg != 0)
1721 			sbi->s_mount_opt |= m->mount_opt;
1722 		else
1723 			sbi->s_mount_opt &= ~m->mount_opt;
1724 	}
1725 	return 1;
1726 }
1727 
1728 static int parse_options(char *options, struct super_block *sb,
1729 			 unsigned long *journal_devnum,
1730 			 unsigned int *journal_ioprio,
1731 			 int is_remount)
1732 {
1733 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1734 	char *p;
1735 	substring_t args[MAX_OPT_ARGS];
1736 	int token;
1737 
1738 	if (!options)
1739 		return 1;
1740 
1741 	while ((p = strsep(&options, ",")) != NULL) {
1742 		if (!*p)
1743 			continue;
1744 		/*
1745 		 * Initialize args struct so we know whether arg was
1746 		 * found; some options take optional arguments.
1747 		 */
1748 		args[0].to = args[0].from = NULL;
1749 		token = match_token(p, tokens, args);
1750 		if (handle_mount_opt(sb, p, token, args, journal_devnum,
1751 				     journal_ioprio, is_remount) < 0)
1752 			return 0;
1753 	}
1754 #ifdef CONFIG_QUOTA
1755 	if (ext4_has_feature_quota(sb) &&
1756 	    (test_opt(sb, USRQUOTA) || test_opt(sb, GRPQUOTA))) {
1757 		ext4_msg(sb, KERN_ERR, "Cannot set quota options when QUOTA "
1758 			 "feature is enabled");
1759 		return 0;
1760 	}
1761 	if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
1762 		if (test_opt(sb, USRQUOTA) && sbi->s_qf_names[USRQUOTA])
1763 			clear_opt(sb, USRQUOTA);
1764 
1765 		if (test_opt(sb, GRPQUOTA) && sbi->s_qf_names[GRPQUOTA])
1766 			clear_opt(sb, GRPQUOTA);
1767 
1768 		if (test_opt(sb, GRPQUOTA) || test_opt(sb, USRQUOTA)) {
1769 			ext4_msg(sb, KERN_ERR, "old and new quota "
1770 					"format mixing");
1771 			return 0;
1772 		}
1773 
1774 		if (!sbi->s_jquota_fmt) {
1775 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1776 					"not specified");
1777 			return 0;
1778 		}
1779 	}
1780 #endif
1781 	if (test_opt(sb, DIOREAD_NOLOCK)) {
1782 		int blocksize =
1783 			BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
1784 
1785 		if (blocksize < PAGE_CACHE_SIZE) {
1786 			ext4_msg(sb, KERN_ERR, "can't mount with "
1787 				 "dioread_nolock if block size != PAGE_SIZE");
1788 			return 0;
1789 		}
1790 	}
1791 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA &&
1792 	    test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
1793 		ext4_msg(sb, KERN_ERR, "can't mount with journal_async_commit "
1794 			 "in data=ordered mode");
1795 		return 0;
1796 	}
1797 	return 1;
1798 }
1799 
1800 static inline void ext4_show_quota_options(struct seq_file *seq,
1801 					   struct super_block *sb)
1802 {
1803 #if defined(CONFIG_QUOTA)
1804 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1805 
1806 	if (sbi->s_jquota_fmt) {
1807 		char *fmtname = "";
1808 
1809 		switch (sbi->s_jquota_fmt) {
1810 		case QFMT_VFS_OLD:
1811 			fmtname = "vfsold";
1812 			break;
1813 		case QFMT_VFS_V0:
1814 			fmtname = "vfsv0";
1815 			break;
1816 		case QFMT_VFS_V1:
1817 			fmtname = "vfsv1";
1818 			break;
1819 		}
1820 		seq_printf(seq, ",jqfmt=%s", fmtname);
1821 	}
1822 
1823 	if (sbi->s_qf_names[USRQUOTA])
1824 		seq_show_option(seq, "usrjquota", sbi->s_qf_names[USRQUOTA]);
1825 
1826 	if (sbi->s_qf_names[GRPQUOTA])
1827 		seq_show_option(seq, "grpjquota", sbi->s_qf_names[GRPQUOTA]);
1828 #endif
1829 }
1830 
1831 static const char *token2str(int token)
1832 {
1833 	const struct match_token *t;
1834 
1835 	for (t = tokens; t->token != Opt_err; t++)
1836 		if (t->token == token && !strchr(t->pattern, '='))
1837 			break;
1838 	return t->pattern;
1839 }
1840 
1841 /*
1842  * Show an option if
1843  *  - it's set to a non-default value OR
1844  *  - if the per-sb default is different from the global default
1845  */
1846 static int _ext4_show_options(struct seq_file *seq, struct super_block *sb,
1847 			      int nodefs)
1848 {
1849 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1850 	struct ext4_super_block *es = sbi->s_es;
1851 	int def_errors, def_mount_opt = nodefs ? 0 : sbi->s_def_mount_opt;
1852 	const struct mount_opts *m;
1853 	char sep = nodefs ? '\n' : ',';
1854 
1855 #define SEQ_OPTS_PUTS(str) seq_printf(seq, "%c" str, sep)
1856 #define SEQ_OPTS_PRINT(str, arg) seq_printf(seq, "%c" str, sep, arg)
1857 
1858 	if (sbi->s_sb_block != 1)
1859 		SEQ_OPTS_PRINT("sb=%llu", sbi->s_sb_block);
1860 
1861 	for (m = ext4_mount_opts; m->token != Opt_err; m++) {
1862 		int want_set = m->flags & MOPT_SET;
1863 		if (((m->flags & (MOPT_SET|MOPT_CLEAR)) == 0) ||
1864 		    (m->flags & MOPT_CLEAR_ERR))
1865 			continue;
1866 		if (!(m->mount_opt & (sbi->s_mount_opt ^ def_mount_opt)))
1867 			continue; /* skip if same as the default */
1868 		if ((want_set &&
1869 		     (sbi->s_mount_opt & m->mount_opt) != m->mount_opt) ||
1870 		    (!want_set && (sbi->s_mount_opt & m->mount_opt)))
1871 			continue; /* select Opt_noFoo vs Opt_Foo */
1872 		SEQ_OPTS_PRINT("%s", token2str(m->token));
1873 	}
1874 
1875 	if (nodefs || !uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT4_DEF_RESUID)) ||
1876 	    le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID)
1877 		SEQ_OPTS_PRINT("resuid=%u",
1878 				from_kuid_munged(&init_user_ns, sbi->s_resuid));
1879 	if (nodefs || !gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT4_DEF_RESGID)) ||
1880 	    le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID)
1881 		SEQ_OPTS_PRINT("resgid=%u",
1882 				from_kgid_munged(&init_user_ns, sbi->s_resgid));
1883 	def_errors = nodefs ? -1 : le16_to_cpu(es->s_errors);
1884 	if (test_opt(sb, ERRORS_RO) && def_errors != EXT4_ERRORS_RO)
1885 		SEQ_OPTS_PUTS("errors=remount-ro");
1886 	if (test_opt(sb, ERRORS_CONT) && def_errors != EXT4_ERRORS_CONTINUE)
1887 		SEQ_OPTS_PUTS("errors=continue");
1888 	if (test_opt(sb, ERRORS_PANIC) && def_errors != EXT4_ERRORS_PANIC)
1889 		SEQ_OPTS_PUTS("errors=panic");
1890 	if (nodefs || sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ)
1891 		SEQ_OPTS_PRINT("commit=%lu", sbi->s_commit_interval / HZ);
1892 	if (nodefs || sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME)
1893 		SEQ_OPTS_PRINT("min_batch_time=%u", sbi->s_min_batch_time);
1894 	if (nodefs || sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME)
1895 		SEQ_OPTS_PRINT("max_batch_time=%u", sbi->s_max_batch_time);
1896 	if (sb->s_flags & MS_I_VERSION)
1897 		SEQ_OPTS_PUTS("i_version");
1898 	if (nodefs || sbi->s_stripe)
1899 		SEQ_OPTS_PRINT("stripe=%lu", sbi->s_stripe);
1900 	if (EXT4_MOUNT_DATA_FLAGS & (sbi->s_mount_opt ^ def_mount_opt)) {
1901 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
1902 			SEQ_OPTS_PUTS("data=journal");
1903 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
1904 			SEQ_OPTS_PUTS("data=ordered");
1905 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
1906 			SEQ_OPTS_PUTS("data=writeback");
1907 	}
1908 	if (nodefs ||
1909 	    sbi->s_inode_readahead_blks != EXT4_DEF_INODE_READAHEAD_BLKS)
1910 		SEQ_OPTS_PRINT("inode_readahead_blks=%u",
1911 			       sbi->s_inode_readahead_blks);
1912 
1913 	if (nodefs || (test_opt(sb, INIT_INODE_TABLE) &&
1914 		       (sbi->s_li_wait_mult != EXT4_DEF_LI_WAIT_MULT)))
1915 		SEQ_OPTS_PRINT("init_itable=%u", sbi->s_li_wait_mult);
1916 	if (nodefs || sbi->s_max_dir_size_kb)
1917 		SEQ_OPTS_PRINT("max_dir_size_kb=%u", sbi->s_max_dir_size_kb);
1918 	if (test_opt(sb, DATA_ERR_ABORT))
1919 		SEQ_OPTS_PUTS("data_err=abort");
1920 
1921 	ext4_show_quota_options(seq, sb);
1922 	return 0;
1923 }
1924 
1925 static int ext4_show_options(struct seq_file *seq, struct dentry *root)
1926 {
1927 	return _ext4_show_options(seq, root->d_sb, 0);
1928 }
1929 
1930 int ext4_seq_options_show(struct seq_file *seq, void *offset)
1931 {
1932 	struct super_block *sb = seq->private;
1933 	int rc;
1934 
1935 	seq_puts(seq, (sb->s_flags & MS_RDONLY) ? "ro" : "rw");
1936 	rc = _ext4_show_options(seq, sb, 1);
1937 	seq_puts(seq, "\n");
1938 	return rc;
1939 }
1940 
1941 static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
1942 			    int read_only)
1943 {
1944 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1945 	int res = 0;
1946 
1947 	if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
1948 		ext4_msg(sb, KERN_ERR, "revision level too high, "
1949 			 "forcing read-only mode");
1950 		res = MS_RDONLY;
1951 	}
1952 	if (read_only)
1953 		goto done;
1954 	if (!(sbi->s_mount_state & EXT4_VALID_FS))
1955 		ext4_msg(sb, KERN_WARNING, "warning: mounting unchecked fs, "
1956 			 "running e2fsck is recommended");
1957 	else if (sbi->s_mount_state & EXT4_ERROR_FS)
1958 		ext4_msg(sb, KERN_WARNING,
1959 			 "warning: mounting fs with errors, "
1960 			 "running e2fsck is recommended");
1961 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) > 0 &&
1962 		 le16_to_cpu(es->s_mnt_count) >=
1963 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
1964 		ext4_msg(sb, KERN_WARNING,
1965 			 "warning: maximal mount count reached, "
1966 			 "running e2fsck is recommended");
1967 	else if (le32_to_cpu(es->s_checkinterval) &&
1968 		(le32_to_cpu(es->s_lastcheck) +
1969 			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
1970 		ext4_msg(sb, KERN_WARNING,
1971 			 "warning: checktime reached, "
1972 			 "running e2fsck is recommended");
1973 	if (!sbi->s_journal)
1974 		es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1975 	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
1976 		es->s_max_mnt_count = cpu_to_le16(EXT4_DFL_MAX_MNT_COUNT);
1977 	le16_add_cpu(&es->s_mnt_count, 1);
1978 	es->s_mtime = cpu_to_le32(get_seconds());
1979 	ext4_update_dynamic_rev(sb);
1980 	if (sbi->s_journal)
1981 		ext4_set_feature_journal_needs_recovery(sb);
1982 
1983 	ext4_commit_super(sb, 1);
1984 done:
1985 	if (test_opt(sb, DEBUG))
1986 		printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, "
1987 				"bpg=%lu, ipg=%lu, mo=%04x, mo2=%04x]\n",
1988 			sb->s_blocksize,
1989 			sbi->s_groups_count,
1990 			EXT4_BLOCKS_PER_GROUP(sb),
1991 			EXT4_INODES_PER_GROUP(sb),
1992 			sbi->s_mount_opt, sbi->s_mount_opt2);
1993 
1994 	cleancache_init_fs(sb);
1995 	return res;
1996 }
1997 
1998 int ext4_alloc_flex_bg_array(struct super_block *sb, ext4_group_t ngroup)
1999 {
2000 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2001 	struct flex_groups *new_groups;
2002 	int size;
2003 
2004 	if (!sbi->s_log_groups_per_flex)
2005 		return 0;
2006 
2007 	size = ext4_flex_group(sbi, ngroup - 1) + 1;
2008 	if (size <= sbi->s_flex_groups_allocated)
2009 		return 0;
2010 
2011 	size = roundup_pow_of_two(size * sizeof(struct flex_groups));
2012 	new_groups = ext4_kvzalloc(size, GFP_KERNEL);
2013 	if (!new_groups) {
2014 		ext4_msg(sb, KERN_ERR, "not enough memory for %d flex groups",
2015 			 size / (int) sizeof(struct flex_groups));
2016 		return -ENOMEM;
2017 	}
2018 
2019 	if (sbi->s_flex_groups) {
2020 		memcpy(new_groups, sbi->s_flex_groups,
2021 		       (sbi->s_flex_groups_allocated *
2022 			sizeof(struct flex_groups)));
2023 		kvfree(sbi->s_flex_groups);
2024 	}
2025 	sbi->s_flex_groups = new_groups;
2026 	sbi->s_flex_groups_allocated = size / sizeof(struct flex_groups);
2027 	return 0;
2028 }
2029 
2030 static int ext4_fill_flex_info(struct super_block *sb)
2031 {
2032 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2033 	struct ext4_group_desc *gdp = NULL;
2034 	ext4_group_t flex_group;
2035 	int i, err;
2036 
2037 	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
2038 	if (sbi->s_log_groups_per_flex < 1 || sbi->s_log_groups_per_flex > 31) {
2039 		sbi->s_log_groups_per_flex = 0;
2040 		return 1;
2041 	}
2042 
2043 	err = ext4_alloc_flex_bg_array(sb, sbi->s_groups_count);
2044 	if (err)
2045 		goto failed;
2046 
2047 	for (i = 0; i < sbi->s_groups_count; i++) {
2048 		gdp = ext4_get_group_desc(sb, i, NULL);
2049 
2050 		flex_group = ext4_flex_group(sbi, i);
2051 		atomic_add(ext4_free_inodes_count(sb, gdp),
2052 			   &sbi->s_flex_groups[flex_group].free_inodes);
2053 		atomic64_add(ext4_free_group_clusters(sb, gdp),
2054 			     &sbi->s_flex_groups[flex_group].free_clusters);
2055 		atomic_add(ext4_used_dirs_count(sb, gdp),
2056 			   &sbi->s_flex_groups[flex_group].used_dirs);
2057 	}
2058 
2059 	return 1;
2060 failed:
2061 	return 0;
2062 }
2063 
2064 static __le16 ext4_group_desc_csum(struct super_block *sb, __u32 block_group,
2065 				   struct ext4_group_desc *gdp)
2066 {
2067 	int offset;
2068 	__u16 crc = 0;
2069 	__le32 le_group = cpu_to_le32(block_group);
2070 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2071 
2072 	if (ext4_has_metadata_csum(sbi->s_sb)) {
2073 		/* Use new metadata_csum algorithm */
2074 		__le16 save_csum;
2075 		__u32 csum32;
2076 
2077 		save_csum = gdp->bg_checksum;
2078 		gdp->bg_checksum = 0;
2079 		csum32 = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&le_group,
2080 				     sizeof(le_group));
2081 		csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp,
2082 				     sbi->s_desc_size);
2083 		gdp->bg_checksum = save_csum;
2084 
2085 		crc = csum32 & 0xFFFF;
2086 		goto out;
2087 	}
2088 
2089 	/* old crc16 code */
2090 	if (!ext4_has_feature_gdt_csum(sb))
2091 		return 0;
2092 
2093 	offset = offsetof(struct ext4_group_desc, bg_checksum);
2094 
2095 	crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
2096 	crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
2097 	crc = crc16(crc, (__u8 *)gdp, offset);
2098 	offset += sizeof(gdp->bg_checksum); /* skip checksum */
2099 	/* for checksum of struct ext4_group_desc do the rest...*/
2100 	if (ext4_has_feature_64bit(sb) &&
2101 	    offset < le16_to_cpu(sbi->s_es->s_desc_size))
2102 		crc = crc16(crc, (__u8 *)gdp + offset,
2103 			    le16_to_cpu(sbi->s_es->s_desc_size) -
2104 				offset);
2105 
2106 out:
2107 	return cpu_to_le16(crc);
2108 }
2109 
2110 int ext4_group_desc_csum_verify(struct super_block *sb, __u32 block_group,
2111 				struct ext4_group_desc *gdp)
2112 {
2113 	if (ext4_has_group_desc_csum(sb) &&
2114 	    (gdp->bg_checksum != ext4_group_desc_csum(sb, block_group, gdp)))
2115 		return 0;
2116 
2117 	return 1;
2118 }
2119 
2120 void ext4_group_desc_csum_set(struct super_block *sb, __u32 block_group,
2121 			      struct ext4_group_desc *gdp)
2122 {
2123 	if (!ext4_has_group_desc_csum(sb))
2124 		return;
2125 	gdp->bg_checksum = ext4_group_desc_csum(sb, block_group, gdp);
2126 }
2127 
2128 /* Called at mount-time, super-block is locked */
2129 static int ext4_check_descriptors(struct super_block *sb,
2130 				  ext4_group_t *first_not_zeroed)
2131 {
2132 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2133 	ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
2134 	ext4_fsblk_t last_block;
2135 	ext4_fsblk_t block_bitmap;
2136 	ext4_fsblk_t inode_bitmap;
2137 	ext4_fsblk_t inode_table;
2138 	int flexbg_flag = 0;
2139 	ext4_group_t i, grp = sbi->s_groups_count;
2140 
2141 	if (ext4_has_feature_flex_bg(sb))
2142 		flexbg_flag = 1;
2143 
2144 	ext4_debug("Checking group descriptors");
2145 
2146 	for (i = 0; i < sbi->s_groups_count; i++) {
2147 		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
2148 
2149 		if (i == sbi->s_groups_count - 1 || flexbg_flag)
2150 			last_block = ext4_blocks_count(sbi->s_es) - 1;
2151 		else
2152 			last_block = first_block +
2153 				(EXT4_BLOCKS_PER_GROUP(sb) - 1);
2154 
2155 		if ((grp == sbi->s_groups_count) &&
2156 		   !(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2157 			grp = i;
2158 
2159 		block_bitmap = ext4_block_bitmap(sb, gdp);
2160 		if (block_bitmap < first_block || block_bitmap > last_block) {
2161 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2162 			       "Block bitmap for group %u not in group "
2163 			       "(block %llu)!", i, block_bitmap);
2164 			return 0;
2165 		}
2166 		inode_bitmap = ext4_inode_bitmap(sb, gdp);
2167 		if (inode_bitmap < first_block || inode_bitmap > last_block) {
2168 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2169 			       "Inode bitmap for group %u not in group "
2170 			       "(block %llu)!", i, inode_bitmap);
2171 			return 0;
2172 		}
2173 		inode_table = ext4_inode_table(sb, gdp);
2174 		if (inode_table < first_block ||
2175 		    inode_table + sbi->s_itb_per_group - 1 > last_block) {
2176 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2177 			       "Inode table for group %u not in group "
2178 			       "(block %llu)!", i, inode_table);
2179 			return 0;
2180 		}
2181 		ext4_lock_group(sb, i);
2182 		if (!ext4_group_desc_csum_verify(sb, i, gdp)) {
2183 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2184 				 "Checksum for group %u failed (%u!=%u)",
2185 				 i, le16_to_cpu(ext4_group_desc_csum(sb, i,
2186 				     gdp)), le16_to_cpu(gdp->bg_checksum));
2187 			if (!(sb->s_flags & MS_RDONLY)) {
2188 				ext4_unlock_group(sb, i);
2189 				return 0;
2190 			}
2191 		}
2192 		ext4_unlock_group(sb, i);
2193 		if (!flexbg_flag)
2194 			first_block += EXT4_BLOCKS_PER_GROUP(sb);
2195 	}
2196 	if (NULL != first_not_zeroed)
2197 		*first_not_zeroed = grp;
2198 	return 1;
2199 }
2200 
2201 /* ext4_orphan_cleanup() walks a singly-linked list of inodes (starting at
2202  * the superblock) which were deleted from all directories, but held open by
2203  * a process at the time of a crash.  We walk the list and try to delete these
2204  * inodes at recovery time (only with a read-write filesystem).
2205  *
2206  * In order to keep the orphan inode chain consistent during traversal (in
2207  * case of crash during recovery), we link each inode into the superblock
2208  * orphan list_head and handle it the same way as an inode deletion during
2209  * normal operation (which journals the operations for us).
2210  *
2211  * We only do an iget() and an iput() on each inode, which is very safe if we
2212  * accidentally point at an in-use or already deleted inode.  The worst that
2213  * can happen in this case is that we get a "bit already cleared" message from
2214  * ext4_free_inode().  The only reason we would point at a wrong inode is if
2215  * e2fsck was run on this filesystem, and it must have already done the orphan
2216  * inode cleanup for us, so we can safely abort without any further action.
2217  */
2218 static void ext4_orphan_cleanup(struct super_block *sb,
2219 				struct ext4_super_block *es)
2220 {
2221 	unsigned int s_flags = sb->s_flags;
2222 	int nr_orphans = 0, nr_truncates = 0;
2223 #ifdef CONFIG_QUOTA
2224 	int i;
2225 #endif
2226 	if (!es->s_last_orphan) {
2227 		jbd_debug(4, "no orphan inodes to clean up\n");
2228 		return;
2229 	}
2230 
2231 	if (bdev_read_only(sb->s_bdev)) {
2232 		ext4_msg(sb, KERN_ERR, "write access "
2233 			"unavailable, skipping orphan cleanup");
2234 		return;
2235 	}
2236 
2237 	/* Check if feature set would not allow a r/w mount */
2238 	if (!ext4_feature_set_ok(sb, 0)) {
2239 		ext4_msg(sb, KERN_INFO, "Skipping orphan cleanup due to "
2240 			 "unknown ROCOMPAT features");
2241 		return;
2242 	}
2243 
2244 	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
2245 		/* don't clear list on RO mount w/ errors */
2246 		if (es->s_last_orphan && !(s_flags & MS_RDONLY)) {
2247 			ext4_msg(sb, KERN_INFO, "Errors on filesystem, "
2248 				  "clearing orphan list.\n");
2249 			es->s_last_orphan = 0;
2250 		}
2251 		jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
2252 		return;
2253 	}
2254 
2255 	if (s_flags & MS_RDONLY) {
2256 		ext4_msg(sb, KERN_INFO, "orphan cleanup on readonly fs");
2257 		sb->s_flags &= ~MS_RDONLY;
2258 	}
2259 #ifdef CONFIG_QUOTA
2260 	/* Needed for iput() to work correctly and not trash data */
2261 	sb->s_flags |= MS_ACTIVE;
2262 	/* Turn on quotas so that they are updated correctly */
2263 	for (i = 0; i < EXT4_MAXQUOTAS; i++) {
2264 		if (EXT4_SB(sb)->s_qf_names[i]) {
2265 			int ret = ext4_quota_on_mount(sb, i);
2266 			if (ret < 0)
2267 				ext4_msg(sb, KERN_ERR,
2268 					"Cannot turn on journaled "
2269 					"quota: error %d", ret);
2270 		}
2271 	}
2272 #endif
2273 
2274 	while (es->s_last_orphan) {
2275 		struct inode *inode;
2276 
2277 		inode = ext4_orphan_get(sb, le32_to_cpu(es->s_last_orphan));
2278 		if (IS_ERR(inode)) {
2279 			es->s_last_orphan = 0;
2280 			break;
2281 		}
2282 
2283 		list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
2284 		dquot_initialize(inode);
2285 		if (inode->i_nlink) {
2286 			if (test_opt(sb, DEBUG))
2287 				ext4_msg(sb, KERN_DEBUG,
2288 					"%s: truncating inode %lu to %lld bytes",
2289 					__func__, inode->i_ino, inode->i_size);
2290 			jbd_debug(2, "truncating inode %lu to %lld bytes\n",
2291 				  inode->i_ino, inode->i_size);
2292 			inode_lock(inode);
2293 			truncate_inode_pages(inode->i_mapping, inode->i_size);
2294 			ext4_truncate(inode);
2295 			inode_unlock(inode);
2296 			nr_truncates++;
2297 		} else {
2298 			if (test_opt(sb, DEBUG))
2299 				ext4_msg(sb, KERN_DEBUG,
2300 					"%s: deleting unreferenced inode %lu",
2301 					__func__, inode->i_ino);
2302 			jbd_debug(2, "deleting unreferenced inode %lu\n",
2303 				  inode->i_ino);
2304 			nr_orphans++;
2305 		}
2306 		iput(inode);  /* The delete magic happens here! */
2307 	}
2308 
2309 #define PLURAL(x) (x), ((x) == 1) ? "" : "s"
2310 
2311 	if (nr_orphans)
2312 		ext4_msg(sb, KERN_INFO, "%d orphan inode%s deleted",
2313 		       PLURAL(nr_orphans));
2314 	if (nr_truncates)
2315 		ext4_msg(sb, KERN_INFO, "%d truncate%s cleaned up",
2316 		       PLURAL(nr_truncates));
2317 #ifdef CONFIG_QUOTA
2318 	/* Turn quotas off */
2319 	for (i = 0; i < EXT4_MAXQUOTAS; i++) {
2320 		if (sb_dqopt(sb)->files[i])
2321 			dquot_quota_off(sb, i);
2322 	}
2323 #endif
2324 	sb->s_flags = s_flags; /* Restore MS_RDONLY status */
2325 }
2326 
2327 /*
2328  * Maximal extent format file size.
2329  * Resulting logical blkno at s_maxbytes must fit in our on-disk
2330  * extent format containers, within a sector_t, and within i_blocks
2331  * in the vfs.  ext4 inode has 48 bits of i_block in fsblock units,
2332  * so that won't be a limiting factor.
2333  *
2334  * However there is other limiting factor. We do store extents in the form
2335  * of starting block and length, hence the resulting length of the extent
2336  * covering maximum file size must fit into on-disk format containers as
2337  * well. Given that length is always by 1 unit bigger than max unit (because
2338  * we count 0 as well) we have to lower the s_maxbytes by one fs block.
2339  *
2340  * Note, this does *not* consider any metadata overhead for vfs i_blocks.
2341  */
2342 static loff_t ext4_max_size(int blkbits, int has_huge_files)
2343 {
2344 	loff_t res;
2345 	loff_t upper_limit = MAX_LFS_FILESIZE;
2346 
2347 	/* small i_blocks in vfs inode? */
2348 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2349 		/*
2350 		 * CONFIG_LBDAF is not enabled implies the inode
2351 		 * i_block represent total blocks in 512 bytes
2352 		 * 32 == size of vfs inode i_blocks * 8
2353 		 */
2354 		upper_limit = (1LL << 32) - 1;
2355 
2356 		/* total blocks in file system block size */
2357 		upper_limit >>= (blkbits - 9);
2358 		upper_limit <<= blkbits;
2359 	}
2360 
2361 	/*
2362 	 * 32-bit extent-start container, ee_block. We lower the maxbytes
2363 	 * by one fs block, so ee_len can cover the extent of maximum file
2364 	 * size
2365 	 */
2366 	res = (1LL << 32) - 1;
2367 	res <<= blkbits;
2368 
2369 	/* Sanity check against vm- & vfs- imposed limits */
2370 	if (res > upper_limit)
2371 		res = upper_limit;
2372 
2373 	return res;
2374 }
2375 
2376 /*
2377  * Maximal bitmap file size.  There is a direct, and {,double-,triple-}indirect
2378  * block limit, and also a limit of (2^48 - 1) 512-byte sectors in i_blocks.
2379  * We need to be 1 filesystem block less than the 2^48 sector limit.
2380  */
2381 static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
2382 {
2383 	loff_t res = EXT4_NDIR_BLOCKS;
2384 	int meta_blocks;
2385 	loff_t upper_limit;
2386 	/* This is calculated to be the largest file size for a dense, block
2387 	 * mapped file such that the file's total number of 512-byte sectors,
2388 	 * including data and all indirect blocks, does not exceed (2^48 - 1).
2389 	 *
2390 	 * __u32 i_blocks_lo and _u16 i_blocks_high represent the total
2391 	 * number of 512-byte sectors of the file.
2392 	 */
2393 
2394 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2395 		/*
2396 		 * !has_huge_files or CONFIG_LBDAF not enabled implies that
2397 		 * the inode i_block field represents total file blocks in
2398 		 * 2^32 512-byte sectors == size of vfs inode i_blocks * 8
2399 		 */
2400 		upper_limit = (1LL << 32) - 1;
2401 
2402 		/* total blocks in file system block size */
2403 		upper_limit >>= (bits - 9);
2404 
2405 	} else {
2406 		/*
2407 		 * We use 48 bit ext4_inode i_blocks
2408 		 * With EXT4_HUGE_FILE_FL set the i_blocks
2409 		 * represent total number of blocks in
2410 		 * file system block size
2411 		 */
2412 		upper_limit = (1LL << 48) - 1;
2413 
2414 	}
2415 
2416 	/* indirect blocks */
2417 	meta_blocks = 1;
2418 	/* double indirect blocks */
2419 	meta_blocks += 1 + (1LL << (bits-2));
2420 	/* tripple indirect blocks */
2421 	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
2422 
2423 	upper_limit -= meta_blocks;
2424 	upper_limit <<= bits;
2425 
2426 	res += 1LL << (bits-2);
2427 	res += 1LL << (2*(bits-2));
2428 	res += 1LL << (3*(bits-2));
2429 	res <<= bits;
2430 	if (res > upper_limit)
2431 		res = upper_limit;
2432 
2433 	if (res > MAX_LFS_FILESIZE)
2434 		res = MAX_LFS_FILESIZE;
2435 
2436 	return res;
2437 }
2438 
2439 static ext4_fsblk_t descriptor_loc(struct super_block *sb,
2440 				   ext4_fsblk_t logical_sb_block, int nr)
2441 {
2442 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2443 	ext4_group_t bg, first_meta_bg;
2444 	int has_super = 0;
2445 
2446 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
2447 
2448 	if (!ext4_has_feature_meta_bg(sb) || nr < first_meta_bg)
2449 		return logical_sb_block + nr + 1;
2450 	bg = sbi->s_desc_per_block * nr;
2451 	if (ext4_bg_has_super(sb, bg))
2452 		has_super = 1;
2453 
2454 	/*
2455 	 * If we have a meta_bg fs with 1k blocks, group 0's GDT is at
2456 	 * block 2, not 1.  If s_first_data_block == 0 (bigalloc is enabled
2457 	 * on modern mke2fs or blksize > 1k on older mke2fs) then we must
2458 	 * compensate.
2459 	 */
2460 	if (sb->s_blocksize == 1024 && nr == 0 &&
2461 	    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block) == 0)
2462 		has_super++;
2463 
2464 	return (has_super + ext4_group_first_block_no(sb, bg));
2465 }
2466 
2467 /**
2468  * ext4_get_stripe_size: Get the stripe size.
2469  * @sbi: In memory super block info
2470  *
2471  * If we have specified it via mount option, then
2472  * use the mount option value. If the value specified at mount time is
2473  * greater than the blocks per group use the super block value.
2474  * If the super block value is greater than blocks per group return 0.
2475  * Allocator needs it be less than blocks per group.
2476  *
2477  */
2478 static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi)
2479 {
2480 	unsigned long stride = le16_to_cpu(sbi->s_es->s_raid_stride);
2481 	unsigned long stripe_width =
2482 			le32_to_cpu(sbi->s_es->s_raid_stripe_width);
2483 	int ret;
2484 
2485 	if (sbi->s_stripe && sbi->s_stripe <= sbi->s_blocks_per_group)
2486 		ret = sbi->s_stripe;
2487 	else if (stripe_width <= sbi->s_blocks_per_group)
2488 		ret = stripe_width;
2489 	else if (stride <= sbi->s_blocks_per_group)
2490 		ret = stride;
2491 	else
2492 		ret = 0;
2493 
2494 	/*
2495 	 * If the stripe width is 1, this makes no sense and
2496 	 * we set it to 0 to turn off stripe handling code.
2497 	 */
2498 	if (ret <= 1)
2499 		ret = 0;
2500 
2501 	return ret;
2502 }
2503 
2504 /*
2505  * Check whether this filesystem can be mounted based on
2506  * the features present and the RDONLY/RDWR mount requested.
2507  * Returns 1 if this filesystem can be mounted as requested,
2508  * 0 if it cannot be.
2509  */
2510 static int ext4_feature_set_ok(struct super_block *sb, int readonly)
2511 {
2512 	if (ext4_has_unknown_ext4_incompat_features(sb)) {
2513 		ext4_msg(sb, KERN_ERR,
2514 			"Couldn't mount because of "
2515 			"unsupported optional features (%x)",
2516 			(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_incompat) &
2517 			~EXT4_FEATURE_INCOMPAT_SUPP));
2518 		return 0;
2519 	}
2520 
2521 	if (readonly)
2522 		return 1;
2523 
2524 	if (ext4_has_feature_readonly(sb)) {
2525 		ext4_msg(sb, KERN_INFO, "filesystem is read-only");
2526 		sb->s_flags |= MS_RDONLY;
2527 		return 1;
2528 	}
2529 
2530 	/* Check that feature set is OK for a read-write mount */
2531 	if (ext4_has_unknown_ext4_ro_compat_features(sb)) {
2532 		ext4_msg(sb, KERN_ERR, "couldn't mount RDWR because of "
2533 			 "unsupported optional features (%x)",
2534 			 (le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_ro_compat) &
2535 				~EXT4_FEATURE_RO_COMPAT_SUPP));
2536 		return 0;
2537 	}
2538 	/*
2539 	 * Large file size enabled file system can only be mounted
2540 	 * read-write on 32-bit systems if kernel is built with CONFIG_LBDAF
2541 	 */
2542 	if (ext4_has_feature_huge_file(sb)) {
2543 		if (sizeof(blkcnt_t) < sizeof(u64)) {
2544 			ext4_msg(sb, KERN_ERR, "Filesystem with huge files "
2545 				 "cannot be mounted RDWR without "
2546 				 "CONFIG_LBDAF");
2547 			return 0;
2548 		}
2549 	}
2550 	if (ext4_has_feature_bigalloc(sb) && !ext4_has_feature_extents(sb)) {
2551 		ext4_msg(sb, KERN_ERR,
2552 			 "Can't support bigalloc feature without "
2553 			 "extents feature\n");
2554 		return 0;
2555 	}
2556 
2557 #ifndef CONFIG_QUOTA
2558 	if (ext4_has_feature_quota(sb) && !readonly) {
2559 		ext4_msg(sb, KERN_ERR,
2560 			 "Filesystem with quota feature cannot be mounted RDWR "
2561 			 "without CONFIG_QUOTA");
2562 		return 0;
2563 	}
2564 	if (ext4_has_feature_project(sb) && !readonly) {
2565 		ext4_msg(sb, KERN_ERR,
2566 			 "Filesystem with project quota feature cannot be mounted RDWR "
2567 			 "without CONFIG_QUOTA");
2568 		return 0;
2569 	}
2570 #endif  /* CONFIG_QUOTA */
2571 	return 1;
2572 }
2573 
2574 /*
2575  * This function is called once a day if we have errors logged
2576  * on the file system
2577  */
2578 static void print_daily_error_info(unsigned long arg)
2579 {
2580 	struct super_block *sb = (struct super_block *) arg;
2581 	struct ext4_sb_info *sbi;
2582 	struct ext4_super_block *es;
2583 
2584 	sbi = EXT4_SB(sb);
2585 	es = sbi->s_es;
2586 
2587 	if (es->s_error_count)
2588 		/* fsck newer than v1.41.13 is needed to clean this condition. */
2589 		ext4_msg(sb, KERN_NOTICE, "error count since last fsck: %u",
2590 			 le32_to_cpu(es->s_error_count));
2591 	if (es->s_first_error_time) {
2592 		printk(KERN_NOTICE "EXT4-fs (%s): initial error at time %u: %.*s:%d",
2593 		       sb->s_id, le32_to_cpu(es->s_first_error_time),
2594 		       (int) sizeof(es->s_first_error_func),
2595 		       es->s_first_error_func,
2596 		       le32_to_cpu(es->s_first_error_line));
2597 		if (es->s_first_error_ino)
2598 			printk(": inode %u",
2599 			       le32_to_cpu(es->s_first_error_ino));
2600 		if (es->s_first_error_block)
2601 			printk(": block %llu", (unsigned long long)
2602 			       le64_to_cpu(es->s_first_error_block));
2603 		printk("\n");
2604 	}
2605 	if (es->s_last_error_time) {
2606 		printk(KERN_NOTICE "EXT4-fs (%s): last error at time %u: %.*s:%d",
2607 		       sb->s_id, le32_to_cpu(es->s_last_error_time),
2608 		       (int) sizeof(es->s_last_error_func),
2609 		       es->s_last_error_func,
2610 		       le32_to_cpu(es->s_last_error_line));
2611 		if (es->s_last_error_ino)
2612 			printk(": inode %u",
2613 			       le32_to_cpu(es->s_last_error_ino));
2614 		if (es->s_last_error_block)
2615 			printk(": block %llu", (unsigned long long)
2616 			       le64_to_cpu(es->s_last_error_block));
2617 		printk("\n");
2618 	}
2619 	mod_timer(&sbi->s_err_report, jiffies + 24*60*60*HZ);  /* Once a day */
2620 }
2621 
2622 /* Find next suitable group and run ext4_init_inode_table */
2623 static int ext4_run_li_request(struct ext4_li_request *elr)
2624 {
2625 	struct ext4_group_desc *gdp = NULL;
2626 	ext4_group_t group, ngroups;
2627 	struct super_block *sb;
2628 	unsigned long timeout = 0;
2629 	int ret = 0;
2630 
2631 	sb = elr->lr_super;
2632 	ngroups = EXT4_SB(sb)->s_groups_count;
2633 
2634 	sb_start_write(sb);
2635 	for (group = elr->lr_next_group; group < ngroups; group++) {
2636 		gdp = ext4_get_group_desc(sb, group, NULL);
2637 		if (!gdp) {
2638 			ret = 1;
2639 			break;
2640 		}
2641 
2642 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2643 			break;
2644 	}
2645 
2646 	if (group >= ngroups)
2647 		ret = 1;
2648 
2649 	if (!ret) {
2650 		timeout = jiffies;
2651 		ret = ext4_init_inode_table(sb, group,
2652 					    elr->lr_timeout ? 0 : 1);
2653 		if (elr->lr_timeout == 0) {
2654 			timeout = (jiffies - timeout) *
2655 				  elr->lr_sbi->s_li_wait_mult;
2656 			elr->lr_timeout = timeout;
2657 		}
2658 		elr->lr_next_sched = jiffies + elr->lr_timeout;
2659 		elr->lr_next_group = group + 1;
2660 	}
2661 	sb_end_write(sb);
2662 
2663 	return ret;
2664 }
2665 
2666 /*
2667  * Remove lr_request from the list_request and free the
2668  * request structure. Should be called with li_list_mtx held
2669  */
2670 static void ext4_remove_li_request(struct ext4_li_request *elr)
2671 {
2672 	struct ext4_sb_info *sbi;
2673 
2674 	if (!elr)
2675 		return;
2676 
2677 	sbi = elr->lr_sbi;
2678 
2679 	list_del(&elr->lr_request);
2680 	sbi->s_li_request = NULL;
2681 	kfree(elr);
2682 }
2683 
2684 static void ext4_unregister_li_request(struct super_block *sb)
2685 {
2686 	mutex_lock(&ext4_li_mtx);
2687 	if (!ext4_li_info) {
2688 		mutex_unlock(&ext4_li_mtx);
2689 		return;
2690 	}
2691 
2692 	mutex_lock(&ext4_li_info->li_list_mtx);
2693 	ext4_remove_li_request(EXT4_SB(sb)->s_li_request);
2694 	mutex_unlock(&ext4_li_info->li_list_mtx);
2695 	mutex_unlock(&ext4_li_mtx);
2696 }
2697 
2698 static struct task_struct *ext4_lazyinit_task;
2699 
2700 /*
2701  * This is the function where ext4lazyinit thread lives. It walks
2702  * through the request list searching for next scheduled filesystem.
2703  * When such a fs is found, run the lazy initialization request
2704  * (ext4_rn_li_request) and keep track of the time spend in this
2705  * function. Based on that time we compute next schedule time of
2706  * the request. When walking through the list is complete, compute
2707  * next waking time and put itself into sleep.
2708  */
2709 static int ext4_lazyinit_thread(void *arg)
2710 {
2711 	struct ext4_lazy_init *eli = (struct ext4_lazy_init *)arg;
2712 	struct list_head *pos, *n;
2713 	struct ext4_li_request *elr;
2714 	unsigned long next_wakeup, cur;
2715 
2716 	BUG_ON(NULL == eli);
2717 
2718 cont_thread:
2719 	while (true) {
2720 		next_wakeup = MAX_JIFFY_OFFSET;
2721 
2722 		mutex_lock(&eli->li_list_mtx);
2723 		if (list_empty(&eli->li_request_list)) {
2724 			mutex_unlock(&eli->li_list_mtx);
2725 			goto exit_thread;
2726 		}
2727 
2728 		list_for_each_safe(pos, n, &eli->li_request_list) {
2729 			elr = list_entry(pos, struct ext4_li_request,
2730 					 lr_request);
2731 
2732 			if (time_after_eq(jiffies, elr->lr_next_sched)) {
2733 				if (ext4_run_li_request(elr) != 0) {
2734 					/* error, remove the lazy_init job */
2735 					ext4_remove_li_request(elr);
2736 					continue;
2737 				}
2738 			}
2739 
2740 			if (time_before(elr->lr_next_sched, next_wakeup))
2741 				next_wakeup = elr->lr_next_sched;
2742 		}
2743 		mutex_unlock(&eli->li_list_mtx);
2744 
2745 		try_to_freeze();
2746 
2747 		cur = jiffies;
2748 		if ((time_after_eq(cur, next_wakeup)) ||
2749 		    (MAX_JIFFY_OFFSET == next_wakeup)) {
2750 			cond_resched();
2751 			continue;
2752 		}
2753 
2754 		schedule_timeout_interruptible(next_wakeup - cur);
2755 
2756 		if (kthread_should_stop()) {
2757 			ext4_clear_request_list();
2758 			goto exit_thread;
2759 		}
2760 	}
2761 
2762 exit_thread:
2763 	/*
2764 	 * It looks like the request list is empty, but we need
2765 	 * to check it under the li_list_mtx lock, to prevent any
2766 	 * additions into it, and of course we should lock ext4_li_mtx
2767 	 * to atomically free the list and ext4_li_info, because at
2768 	 * this point another ext4 filesystem could be registering
2769 	 * new one.
2770 	 */
2771 	mutex_lock(&ext4_li_mtx);
2772 	mutex_lock(&eli->li_list_mtx);
2773 	if (!list_empty(&eli->li_request_list)) {
2774 		mutex_unlock(&eli->li_list_mtx);
2775 		mutex_unlock(&ext4_li_mtx);
2776 		goto cont_thread;
2777 	}
2778 	mutex_unlock(&eli->li_list_mtx);
2779 	kfree(ext4_li_info);
2780 	ext4_li_info = NULL;
2781 	mutex_unlock(&ext4_li_mtx);
2782 
2783 	return 0;
2784 }
2785 
2786 static void ext4_clear_request_list(void)
2787 {
2788 	struct list_head *pos, *n;
2789 	struct ext4_li_request *elr;
2790 
2791 	mutex_lock(&ext4_li_info->li_list_mtx);
2792 	list_for_each_safe(pos, n, &ext4_li_info->li_request_list) {
2793 		elr = list_entry(pos, struct ext4_li_request,
2794 				 lr_request);
2795 		ext4_remove_li_request(elr);
2796 	}
2797 	mutex_unlock(&ext4_li_info->li_list_mtx);
2798 }
2799 
2800 static int ext4_run_lazyinit_thread(void)
2801 {
2802 	ext4_lazyinit_task = kthread_run(ext4_lazyinit_thread,
2803 					 ext4_li_info, "ext4lazyinit");
2804 	if (IS_ERR(ext4_lazyinit_task)) {
2805 		int err = PTR_ERR(ext4_lazyinit_task);
2806 		ext4_clear_request_list();
2807 		kfree(ext4_li_info);
2808 		ext4_li_info = NULL;
2809 		printk(KERN_CRIT "EXT4-fs: error %d creating inode table "
2810 				 "initialization thread\n",
2811 				 err);
2812 		return err;
2813 	}
2814 	ext4_li_info->li_state |= EXT4_LAZYINIT_RUNNING;
2815 	return 0;
2816 }
2817 
2818 /*
2819  * Check whether it make sense to run itable init. thread or not.
2820  * If there is at least one uninitialized inode table, return
2821  * corresponding group number, else the loop goes through all
2822  * groups and return total number of groups.
2823  */
2824 static ext4_group_t ext4_has_uninit_itable(struct super_block *sb)
2825 {
2826 	ext4_group_t group, ngroups = EXT4_SB(sb)->s_groups_count;
2827 	struct ext4_group_desc *gdp = NULL;
2828 
2829 	for (group = 0; group < ngroups; group++) {
2830 		gdp = ext4_get_group_desc(sb, group, NULL);
2831 		if (!gdp)
2832 			continue;
2833 
2834 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2835 			break;
2836 	}
2837 
2838 	return group;
2839 }
2840 
2841 static int ext4_li_info_new(void)
2842 {
2843 	struct ext4_lazy_init *eli = NULL;
2844 
2845 	eli = kzalloc(sizeof(*eli), GFP_KERNEL);
2846 	if (!eli)
2847 		return -ENOMEM;
2848 
2849 	INIT_LIST_HEAD(&eli->li_request_list);
2850 	mutex_init(&eli->li_list_mtx);
2851 
2852 	eli->li_state |= EXT4_LAZYINIT_QUIT;
2853 
2854 	ext4_li_info = eli;
2855 
2856 	return 0;
2857 }
2858 
2859 static struct ext4_li_request *ext4_li_request_new(struct super_block *sb,
2860 					    ext4_group_t start)
2861 {
2862 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2863 	struct ext4_li_request *elr;
2864 
2865 	elr = kzalloc(sizeof(*elr), GFP_KERNEL);
2866 	if (!elr)
2867 		return NULL;
2868 
2869 	elr->lr_super = sb;
2870 	elr->lr_sbi = sbi;
2871 	elr->lr_next_group = start;
2872 
2873 	/*
2874 	 * Randomize first schedule time of the request to
2875 	 * spread the inode table initialization requests
2876 	 * better.
2877 	 */
2878 	elr->lr_next_sched = jiffies + (prandom_u32() %
2879 				(EXT4_DEF_LI_MAX_START_DELAY * HZ));
2880 	return elr;
2881 }
2882 
2883 int ext4_register_li_request(struct super_block *sb,
2884 			     ext4_group_t first_not_zeroed)
2885 {
2886 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2887 	struct ext4_li_request *elr = NULL;
2888 	ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
2889 	int ret = 0;
2890 
2891 	mutex_lock(&ext4_li_mtx);
2892 	if (sbi->s_li_request != NULL) {
2893 		/*
2894 		 * Reset timeout so it can be computed again, because
2895 		 * s_li_wait_mult might have changed.
2896 		 */
2897 		sbi->s_li_request->lr_timeout = 0;
2898 		goto out;
2899 	}
2900 
2901 	if (first_not_zeroed == ngroups ||
2902 	    (sb->s_flags & MS_RDONLY) ||
2903 	    !test_opt(sb, INIT_INODE_TABLE))
2904 		goto out;
2905 
2906 	elr = ext4_li_request_new(sb, first_not_zeroed);
2907 	if (!elr) {
2908 		ret = -ENOMEM;
2909 		goto out;
2910 	}
2911 
2912 	if (NULL == ext4_li_info) {
2913 		ret = ext4_li_info_new();
2914 		if (ret)
2915 			goto out;
2916 	}
2917 
2918 	mutex_lock(&ext4_li_info->li_list_mtx);
2919 	list_add(&elr->lr_request, &ext4_li_info->li_request_list);
2920 	mutex_unlock(&ext4_li_info->li_list_mtx);
2921 
2922 	sbi->s_li_request = elr;
2923 	/*
2924 	 * set elr to NULL here since it has been inserted to
2925 	 * the request_list and the removal and free of it is
2926 	 * handled by ext4_clear_request_list from now on.
2927 	 */
2928 	elr = NULL;
2929 
2930 	if (!(ext4_li_info->li_state & EXT4_LAZYINIT_RUNNING)) {
2931 		ret = ext4_run_lazyinit_thread();
2932 		if (ret)
2933 			goto out;
2934 	}
2935 out:
2936 	mutex_unlock(&ext4_li_mtx);
2937 	if (ret)
2938 		kfree(elr);
2939 	return ret;
2940 }
2941 
2942 /*
2943  * We do not need to lock anything since this is called on
2944  * module unload.
2945  */
2946 static void ext4_destroy_lazyinit_thread(void)
2947 {
2948 	/*
2949 	 * If thread exited earlier
2950 	 * there's nothing to be done.
2951 	 */
2952 	if (!ext4_li_info || !ext4_lazyinit_task)
2953 		return;
2954 
2955 	kthread_stop(ext4_lazyinit_task);
2956 }
2957 
2958 static int set_journal_csum_feature_set(struct super_block *sb)
2959 {
2960 	int ret = 1;
2961 	int compat, incompat;
2962 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2963 
2964 	if (ext4_has_metadata_csum(sb)) {
2965 		/* journal checksum v3 */
2966 		compat = 0;
2967 		incompat = JBD2_FEATURE_INCOMPAT_CSUM_V3;
2968 	} else {
2969 		/* journal checksum v1 */
2970 		compat = JBD2_FEATURE_COMPAT_CHECKSUM;
2971 		incompat = 0;
2972 	}
2973 
2974 	jbd2_journal_clear_features(sbi->s_journal,
2975 			JBD2_FEATURE_COMPAT_CHECKSUM, 0,
2976 			JBD2_FEATURE_INCOMPAT_CSUM_V3 |
2977 			JBD2_FEATURE_INCOMPAT_CSUM_V2);
2978 	if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
2979 		ret = jbd2_journal_set_features(sbi->s_journal,
2980 				compat, 0,
2981 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT |
2982 				incompat);
2983 	} else if (test_opt(sb, JOURNAL_CHECKSUM)) {
2984 		ret = jbd2_journal_set_features(sbi->s_journal,
2985 				compat, 0,
2986 				incompat);
2987 		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
2988 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
2989 	} else {
2990 		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
2991 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
2992 	}
2993 
2994 	return ret;
2995 }
2996 
2997 /*
2998  * Note: calculating the overhead so we can be compatible with
2999  * historical BSD practice is quite difficult in the face of
3000  * clusters/bigalloc.  This is because multiple metadata blocks from
3001  * different block group can end up in the same allocation cluster.
3002  * Calculating the exact overhead in the face of clustered allocation
3003  * requires either O(all block bitmaps) in memory or O(number of block
3004  * groups**2) in time.  We will still calculate the superblock for
3005  * older file systems --- and if we come across with a bigalloc file
3006  * system with zero in s_overhead_clusters the estimate will be close to
3007  * correct especially for very large cluster sizes --- but for newer
3008  * file systems, it's better to calculate this figure once at mkfs
3009  * time, and store it in the superblock.  If the superblock value is
3010  * present (even for non-bigalloc file systems), we will use it.
3011  */
3012 static int count_overhead(struct super_block *sb, ext4_group_t grp,
3013 			  char *buf)
3014 {
3015 	struct ext4_sb_info	*sbi = EXT4_SB(sb);
3016 	struct ext4_group_desc	*gdp;
3017 	ext4_fsblk_t		first_block, last_block, b;
3018 	ext4_group_t		i, ngroups = ext4_get_groups_count(sb);
3019 	int			s, j, count = 0;
3020 
3021 	if (!ext4_has_feature_bigalloc(sb))
3022 		return (ext4_bg_has_super(sb, grp) + ext4_bg_num_gdb(sb, grp) +
3023 			sbi->s_itb_per_group + 2);
3024 
3025 	first_block = le32_to_cpu(sbi->s_es->s_first_data_block) +
3026 		(grp * EXT4_BLOCKS_PER_GROUP(sb));
3027 	last_block = first_block + EXT4_BLOCKS_PER_GROUP(sb) - 1;
3028 	for (i = 0; i < ngroups; i++) {
3029 		gdp = ext4_get_group_desc(sb, i, NULL);
3030 		b = ext4_block_bitmap(sb, gdp);
3031 		if (b >= first_block && b <= last_block) {
3032 			ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf);
3033 			count++;
3034 		}
3035 		b = ext4_inode_bitmap(sb, gdp);
3036 		if (b >= first_block && b <= last_block) {
3037 			ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf);
3038 			count++;
3039 		}
3040 		b = ext4_inode_table(sb, gdp);
3041 		if (b >= first_block && b + sbi->s_itb_per_group <= last_block)
3042 			for (j = 0; j < sbi->s_itb_per_group; j++, b++) {
3043 				int c = EXT4_B2C(sbi, b - first_block);
3044 				ext4_set_bit(c, buf);
3045 				count++;
3046 			}
3047 		if (i != grp)
3048 			continue;
3049 		s = 0;
3050 		if (ext4_bg_has_super(sb, grp)) {
3051 			ext4_set_bit(s++, buf);
3052 			count++;
3053 		}
3054 		for (j = ext4_bg_num_gdb(sb, grp); j > 0; j--) {
3055 			ext4_set_bit(EXT4_B2C(sbi, s++), buf);
3056 			count++;
3057 		}
3058 	}
3059 	if (!count)
3060 		return 0;
3061 	return EXT4_CLUSTERS_PER_GROUP(sb) -
3062 		ext4_count_free(buf, EXT4_CLUSTERS_PER_GROUP(sb) / 8);
3063 }
3064 
3065 /*
3066  * Compute the overhead and stash it in sbi->s_overhead
3067  */
3068 int ext4_calculate_overhead(struct super_block *sb)
3069 {
3070 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3071 	struct ext4_super_block *es = sbi->s_es;
3072 	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
3073 	ext4_fsblk_t overhead = 0;
3074 	char *buf = (char *) get_zeroed_page(GFP_NOFS);
3075 
3076 	if (!buf)
3077 		return -ENOMEM;
3078 
3079 	/*
3080 	 * Compute the overhead (FS structures).  This is constant
3081 	 * for a given filesystem unless the number of block groups
3082 	 * changes so we cache the previous value until it does.
3083 	 */
3084 
3085 	/*
3086 	 * All of the blocks before first_data_block are overhead
3087 	 */
3088 	overhead = EXT4_B2C(sbi, le32_to_cpu(es->s_first_data_block));
3089 
3090 	/*
3091 	 * Add the overhead found in each block group
3092 	 */
3093 	for (i = 0; i < ngroups; i++) {
3094 		int blks;
3095 
3096 		blks = count_overhead(sb, i, buf);
3097 		overhead += blks;
3098 		if (blks)
3099 			memset(buf, 0, PAGE_SIZE);
3100 		cond_resched();
3101 	}
3102 	/* Add the internal journal blocks as well */
3103 	if (sbi->s_journal && !sbi->journal_bdev)
3104 		overhead += EXT4_NUM_B2C(sbi, sbi->s_journal->j_maxlen);
3105 
3106 	sbi->s_overhead = overhead;
3107 	smp_wmb();
3108 	free_page((unsigned long) buf);
3109 	return 0;
3110 }
3111 
3112 static void ext4_set_resv_clusters(struct super_block *sb)
3113 {
3114 	ext4_fsblk_t resv_clusters;
3115 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3116 
3117 	/*
3118 	 * There's no need to reserve anything when we aren't using extents.
3119 	 * The space estimates are exact, there are no unwritten extents,
3120 	 * hole punching doesn't need new metadata... This is needed especially
3121 	 * to keep ext2/3 backward compatibility.
3122 	 */
3123 	if (!ext4_has_feature_extents(sb))
3124 		return;
3125 	/*
3126 	 * By default we reserve 2% or 4096 clusters, whichever is smaller.
3127 	 * This should cover the situations where we can not afford to run
3128 	 * out of space like for example punch hole, or converting
3129 	 * unwritten extents in delalloc path. In most cases such
3130 	 * allocation would require 1, or 2 blocks, higher numbers are
3131 	 * very rare.
3132 	 */
3133 	resv_clusters = (ext4_blocks_count(sbi->s_es) >>
3134 			 sbi->s_cluster_bits);
3135 
3136 	do_div(resv_clusters, 50);
3137 	resv_clusters = min_t(ext4_fsblk_t, resv_clusters, 4096);
3138 
3139 	atomic64_set(&sbi->s_resv_clusters, resv_clusters);
3140 }
3141 
3142 static int ext4_fill_super(struct super_block *sb, void *data, int silent)
3143 {
3144 	char *orig_data = kstrdup(data, GFP_KERNEL);
3145 	struct buffer_head *bh;
3146 	struct ext4_super_block *es = NULL;
3147 	struct ext4_sb_info *sbi;
3148 	ext4_fsblk_t block;
3149 	ext4_fsblk_t sb_block = get_sb_block(&data);
3150 	ext4_fsblk_t logical_sb_block;
3151 	unsigned long offset = 0;
3152 	unsigned long journal_devnum = 0;
3153 	unsigned long def_mount_opts;
3154 	struct inode *root;
3155 	const char *descr;
3156 	int ret = -ENOMEM;
3157 	int blocksize, clustersize;
3158 	unsigned int db_count;
3159 	unsigned int i;
3160 	int needs_recovery, has_huge_files, has_bigalloc;
3161 	__u64 blocks_count;
3162 	int err = 0;
3163 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
3164 	ext4_group_t first_not_zeroed;
3165 
3166 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
3167 	if (!sbi)
3168 		goto out_free_orig;
3169 
3170 	sbi->s_blockgroup_lock =
3171 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
3172 	if (!sbi->s_blockgroup_lock) {
3173 		kfree(sbi);
3174 		goto out_free_orig;
3175 	}
3176 	sb->s_fs_info = sbi;
3177 	sbi->s_sb = sb;
3178 	sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
3179 	sbi->s_sb_block = sb_block;
3180 	if (sb->s_bdev->bd_part)
3181 		sbi->s_sectors_written_start =
3182 			part_stat_read(sb->s_bdev->bd_part, sectors[1]);
3183 
3184 	/* Cleanup superblock name */
3185 	strreplace(sb->s_id, '/', '!');
3186 
3187 	/* -EINVAL is default */
3188 	ret = -EINVAL;
3189 	blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
3190 	if (!blocksize) {
3191 		ext4_msg(sb, KERN_ERR, "unable to set blocksize");
3192 		goto out_fail;
3193 	}
3194 
3195 	/*
3196 	 * The ext4 superblock will not be buffer aligned for other than 1kB
3197 	 * block sizes.  We need to calculate the offset from buffer start.
3198 	 */
3199 	if (blocksize != EXT4_MIN_BLOCK_SIZE) {
3200 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3201 		offset = do_div(logical_sb_block, blocksize);
3202 	} else {
3203 		logical_sb_block = sb_block;
3204 	}
3205 
3206 	if (!(bh = sb_bread_unmovable(sb, logical_sb_block))) {
3207 		ext4_msg(sb, KERN_ERR, "unable to read superblock");
3208 		goto out_fail;
3209 	}
3210 	/*
3211 	 * Note: s_es must be initialized as soon as possible because
3212 	 *       some ext4 macro-instructions depend on its value
3213 	 */
3214 	es = (struct ext4_super_block *) (bh->b_data + offset);
3215 	sbi->s_es = es;
3216 	sb->s_magic = le16_to_cpu(es->s_magic);
3217 	if (sb->s_magic != EXT4_SUPER_MAGIC)
3218 		goto cantfind_ext4;
3219 	sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
3220 
3221 	/* Warn if metadata_csum and gdt_csum are both set. */
3222 	if (ext4_has_feature_metadata_csum(sb) &&
3223 	    ext4_has_feature_gdt_csum(sb))
3224 		ext4_warning(sb, "metadata_csum and uninit_bg are "
3225 			     "redundant flags; please run fsck.");
3226 
3227 	/* Check for a known checksum algorithm */
3228 	if (!ext4_verify_csum_type(sb, es)) {
3229 		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
3230 			 "unknown checksum algorithm.");
3231 		silent = 1;
3232 		goto cantfind_ext4;
3233 	}
3234 
3235 	/* Load the checksum driver */
3236 	if (ext4_has_feature_metadata_csum(sb)) {
3237 		sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
3238 		if (IS_ERR(sbi->s_chksum_driver)) {
3239 			ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
3240 			ret = PTR_ERR(sbi->s_chksum_driver);
3241 			sbi->s_chksum_driver = NULL;
3242 			goto failed_mount;
3243 		}
3244 	}
3245 
3246 	/* Check superblock checksum */
3247 	if (!ext4_superblock_csum_verify(sb, es)) {
3248 		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
3249 			 "invalid superblock checksum.  Run e2fsck?");
3250 		silent = 1;
3251 		ret = -EFSBADCRC;
3252 		goto cantfind_ext4;
3253 	}
3254 
3255 	/* Precompute checksum seed for all metadata */
3256 	if (ext4_has_feature_csum_seed(sb))
3257 		sbi->s_csum_seed = le32_to_cpu(es->s_checksum_seed);
3258 	else if (ext4_has_metadata_csum(sb))
3259 		sbi->s_csum_seed = ext4_chksum(sbi, ~0, es->s_uuid,
3260 					       sizeof(es->s_uuid));
3261 
3262 	/* Set defaults before we parse the mount options */
3263 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
3264 	set_opt(sb, INIT_INODE_TABLE);
3265 	if (def_mount_opts & EXT4_DEFM_DEBUG)
3266 		set_opt(sb, DEBUG);
3267 	if (def_mount_opts & EXT4_DEFM_BSDGROUPS)
3268 		set_opt(sb, GRPID);
3269 	if (def_mount_opts & EXT4_DEFM_UID16)
3270 		set_opt(sb, NO_UID32);
3271 	/* xattr user namespace & acls are now defaulted on */
3272 	set_opt(sb, XATTR_USER);
3273 #ifdef CONFIG_EXT4_FS_POSIX_ACL
3274 	set_opt(sb, POSIX_ACL);
3275 #endif
3276 	/* don't forget to enable journal_csum when metadata_csum is enabled. */
3277 	if (ext4_has_metadata_csum(sb))
3278 		set_opt(sb, JOURNAL_CHECKSUM);
3279 
3280 	if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA)
3281 		set_opt(sb, JOURNAL_DATA);
3282 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_ORDERED)
3283 		set_opt(sb, ORDERED_DATA);
3284 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_WBACK)
3285 		set_opt(sb, WRITEBACK_DATA);
3286 
3287 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_PANIC)
3288 		set_opt(sb, ERRORS_PANIC);
3289 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_CONTINUE)
3290 		set_opt(sb, ERRORS_CONT);
3291 	else
3292 		set_opt(sb, ERRORS_RO);
3293 	/* block_validity enabled by default; disable with noblock_validity */
3294 	set_opt(sb, BLOCK_VALIDITY);
3295 	if (def_mount_opts & EXT4_DEFM_DISCARD)
3296 		set_opt(sb, DISCARD);
3297 
3298 	sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
3299 	sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
3300 	sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ;
3301 	sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;
3302 	sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;
3303 
3304 	if ((def_mount_opts & EXT4_DEFM_NOBARRIER) == 0)
3305 		set_opt(sb, BARRIER);
3306 
3307 	/*
3308 	 * enable delayed allocation by default
3309 	 * Use -o nodelalloc to turn it off
3310 	 */
3311 	if (!IS_EXT3_SB(sb) && !IS_EXT2_SB(sb) &&
3312 	    ((def_mount_opts & EXT4_DEFM_NODELALLOC) == 0))
3313 		set_opt(sb, DELALLOC);
3314 
3315 	/*
3316 	 * set default s_li_wait_mult for lazyinit, for the case there is
3317 	 * no mount option specified.
3318 	 */
3319 	sbi->s_li_wait_mult = EXT4_DEF_LI_WAIT_MULT;
3320 
3321 	if (!parse_options((char *) sbi->s_es->s_mount_opts, sb,
3322 			   &journal_devnum, &journal_ioprio, 0)) {
3323 		ext4_msg(sb, KERN_WARNING,
3324 			 "failed to parse options in superblock: %s",
3325 			 sbi->s_es->s_mount_opts);
3326 	}
3327 	sbi->s_def_mount_opt = sbi->s_mount_opt;
3328 	if (!parse_options((char *) data, sb, &journal_devnum,
3329 			   &journal_ioprio, 0))
3330 		goto failed_mount;
3331 
3332 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
3333 		printk_once(KERN_WARNING "EXT4-fs: Warning: mounting "
3334 			    "with data=journal disables delayed "
3335 			    "allocation and O_DIRECT support!\n");
3336 		if (test_opt2(sb, EXPLICIT_DELALLOC)) {
3337 			ext4_msg(sb, KERN_ERR, "can't mount with "
3338 				 "both data=journal and delalloc");
3339 			goto failed_mount;
3340 		}
3341 		if (test_opt(sb, DIOREAD_NOLOCK)) {
3342 			ext4_msg(sb, KERN_ERR, "can't mount with "
3343 				 "both data=journal and dioread_nolock");
3344 			goto failed_mount;
3345 		}
3346 		if (test_opt(sb, DAX)) {
3347 			ext4_msg(sb, KERN_ERR, "can't mount with "
3348 				 "both data=journal and dax");
3349 			goto failed_mount;
3350 		}
3351 		if (test_opt(sb, DELALLOC))
3352 			clear_opt(sb, DELALLOC);
3353 	} else {
3354 		sb->s_iflags |= SB_I_CGROUPWB;
3355 	}
3356 
3357 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
3358 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
3359 
3360 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
3361 	    (ext4_has_compat_features(sb) ||
3362 	     ext4_has_ro_compat_features(sb) ||
3363 	     ext4_has_incompat_features(sb)))
3364 		ext4_msg(sb, KERN_WARNING,
3365 		       "feature flags set on rev 0 fs, "
3366 		       "running e2fsck is recommended");
3367 
3368 	if (es->s_creator_os == cpu_to_le32(EXT4_OS_HURD)) {
3369 		set_opt2(sb, HURD_COMPAT);
3370 		if (ext4_has_feature_64bit(sb)) {
3371 			ext4_msg(sb, KERN_ERR,
3372 				 "The Hurd can't support 64-bit file systems");
3373 			goto failed_mount;
3374 		}
3375 	}
3376 
3377 	if (IS_EXT2_SB(sb)) {
3378 		if (ext2_feature_set_ok(sb))
3379 			ext4_msg(sb, KERN_INFO, "mounting ext2 file system "
3380 				 "using the ext4 subsystem");
3381 		else {
3382 			ext4_msg(sb, KERN_ERR, "couldn't mount as ext2 due "
3383 				 "to feature incompatibilities");
3384 			goto failed_mount;
3385 		}
3386 	}
3387 
3388 	if (IS_EXT3_SB(sb)) {
3389 		if (ext3_feature_set_ok(sb))
3390 			ext4_msg(sb, KERN_INFO, "mounting ext3 file system "
3391 				 "using the ext4 subsystem");
3392 		else {
3393 			ext4_msg(sb, KERN_ERR, "couldn't mount as ext3 due "
3394 				 "to feature incompatibilities");
3395 			goto failed_mount;
3396 		}
3397 	}
3398 
3399 	/*
3400 	 * Check feature flags regardless of the revision level, since we
3401 	 * previously didn't change the revision level when setting the flags,
3402 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
3403 	 */
3404 	if (!ext4_feature_set_ok(sb, (sb->s_flags & MS_RDONLY)))
3405 		goto failed_mount;
3406 
3407 	blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
3408 	if (blocksize < EXT4_MIN_BLOCK_SIZE ||
3409 	    blocksize > EXT4_MAX_BLOCK_SIZE) {
3410 		ext4_msg(sb, KERN_ERR,
3411 		       "Unsupported filesystem blocksize %d", blocksize);
3412 		goto failed_mount;
3413 	}
3414 
3415 	if (sbi->s_mount_opt & EXT4_MOUNT_DAX) {
3416 		if (blocksize != PAGE_SIZE) {
3417 			ext4_msg(sb, KERN_ERR,
3418 					"error: unsupported blocksize for dax");
3419 			goto failed_mount;
3420 		}
3421 		if (!sb->s_bdev->bd_disk->fops->direct_access) {
3422 			ext4_msg(sb, KERN_ERR,
3423 					"error: device does not support dax");
3424 			goto failed_mount;
3425 		}
3426 	}
3427 
3428 	if (ext4_has_feature_encrypt(sb) && es->s_encryption_level) {
3429 		ext4_msg(sb, KERN_ERR, "Unsupported encryption level %d",
3430 			 es->s_encryption_level);
3431 		goto failed_mount;
3432 	}
3433 
3434 	if (sb->s_blocksize != blocksize) {
3435 		/* Validate the filesystem blocksize */
3436 		if (!sb_set_blocksize(sb, blocksize)) {
3437 			ext4_msg(sb, KERN_ERR, "bad block size %d",
3438 					blocksize);
3439 			goto failed_mount;
3440 		}
3441 
3442 		brelse(bh);
3443 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3444 		offset = do_div(logical_sb_block, blocksize);
3445 		bh = sb_bread_unmovable(sb, logical_sb_block);
3446 		if (!bh) {
3447 			ext4_msg(sb, KERN_ERR,
3448 			       "Can't read superblock on 2nd try");
3449 			goto failed_mount;
3450 		}
3451 		es = (struct ext4_super_block *)(bh->b_data + offset);
3452 		sbi->s_es = es;
3453 		if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
3454 			ext4_msg(sb, KERN_ERR,
3455 			       "Magic mismatch, very weird!");
3456 			goto failed_mount;
3457 		}
3458 	}
3459 
3460 	has_huge_files = ext4_has_feature_huge_file(sb);
3461 	sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits,
3462 						      has_huge_files);
3463 	sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits, has_huge_files);
3464 
3465 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) {
3466 		sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE;
3467 		sbi->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
3468 	} else {
3469 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
3470 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
3471 		if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
3472 		    (!is_power_of_2(sbi->s_inode_size)) ||
3473 		    (sbi->s_inode_size > blocksize)) {
3474 			ext4_msg(sb, KERN_ERR,
3475 			       "unsupported inode size: %d",
3476 			       sbi->s_inode_size);
3477 			goto failed_mount;
3478 		}
3479 		if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE)
3480 			sb->s_time_gran = 1 << (EXT4_EPOCH_BITS - 2);
3481 	}
3482 
3483 	sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
3484 	if (ext4_has_feature_64bit(sb)) {
3485 		if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT ||
3486 		    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
3487 		    !is_power_of_2(sbi->s_desc_size)) {
3488 			ext4_msg(sb, KERN_ERR,
3489 			       "unsupported descriptor size %lu",
3490 			       sbi->s_desc_size);
3491 			goto failed_mount;
3492 		}
3493 	} else
3494 		sbi->s_desc_size = EXT4_MIN_DESC_SIZE;
3495 
3496 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
3497 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
3498 	if (EXT4_INODE_SIZE(sb) == 0 || EXT4_INODES_PER_GROUP(sb) == 0)
3499 		goto cantfind_ext4;
3500 
3501 	sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
3502 	if (sbi->s_inodes_per_block == 0)
3503 		goto cantfind_ext4;
3504 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
3505 					sbi->s_inodes_per_block;
3506 	sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
3507 	sbi->s_sbh = bh;
3508 	sbi->s_mount_state = le16_to_cpu(es->s_state);
3509 	sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
3510 	sbi->s_desc_per_block_bits = ilog2(EXT4_DESC_PER_BLOCK(sb));
3511 
3512 	for (i = 0; i < 4; i++)
3513 		sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
3514 	sbi->s_def_hash_version = es->s_def_hash_version;
3515 	if (ext4_has_feature_dir_index(sb)) {
3516 		i = le32_to_cpu(es->s_flags);
3517 		if (i & EXT2_FLAGS_UNSIGNED_HASH)
3518 			sbi->s_hash_unsigned = 3;
3519 		else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) {
3520 #ifdef __CHAR_UNSIGNED__
3521 			if (!(sb->s_flags & MS_RDONLY))
3522 				es->s_flags |=
3523 					cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH);
3524 			sbi->s_hash_unsigned = 3;
3525 #else
3526 			if (!(sb->s_flags & MS_RDONLY))
3527 				es->s_flags |=
3528 					cpu_to_le32(EXT2_FLAGS_SIGNED_HASH);
3529 #endif
3530 		}
3531 	}
3532 
3533 	/* Handle clustersize */
3534 	clustersize = BLOCK_SIZE << le32_to_cpu(es->s_log_cluster_size);
3535 	has_bigalloc = ext4_has_feature_bigalloc(sb);
3536 	if (has_bigalloc) {
3537 		if (clustersize < blocksize) {
3538 			ext4_msg(sb, KERN_ERR,
3539 				 "cluster size (%d) smaller than "
3540 				 "block size (%d)", clustersize, blocksize);
3541 			goto failed_mount;
3542 		}
3543 		sbi->s_cluster_bits = le32_to_cpu(es->s_log_cluster_size) -
3544 			le32_to_cpu(es->s_log_block_size);
3545 		sbi->s_clusters_per_group =
3546 			le32_to_cpu(es->s_clusters_per_group);
3547 		if (sbi->s_clusters_per_group > blocksize * 8) {
3548 			ext4_msg(sb, KERN_ERR,
3549 				 "#clusters per group too big: %lu",
3550 				 sbi->s_clusters_per_group);
3551 			goto failed_mount;
3552 		}
3553 		if (sbi->s_blocks_per_group !=
3554 		    (sbi->s_clusters_per_group * (clustersize / blocksize))) {
3555 			ext4_msg(sb, KERN_ERR, "blocks per group (%lu) and "
3556 				 "clusters per group (%lu) inconsistent",
3557 				 sbi->s_blocks_per_group,
3558 				 sbi->s_clusters_per_group);
3559 			goto failed_mount;
3560 		}
3561 	} else {
3562 		if (clustersize != blocksize) {
3563 			ext4_warning(sb, "fragment/cluster size (%d) != "
3564 				     "block size (%d)", clustersize,
3565 				     blocksize);
3566 			clustersize = blocksize;
3567 		}
3568 		if (sbi->s_blocks_per_group > blocksize * 8) {
3569 			ext4_msg(sb, KERN_ERR,
3570 				 "#blocks per group too big: %lu",
3571 				 sbi->s_blocks_per_group);
3572 			goto failed_mount;
3573 		}
3574 		sbi->s_clusters_per_group = sbi->s_blocks_per_group;
3575 		sbi->s_cluster_bits = 0;
3576 	}
3577 	sbi->s_cluster_ratio = clustersize / blocksize;
3578 
3579 	if (sbi->s_inodes_per_group > blocksize * 8) {
3580 		ext4_msg(sb, KERN_ERR,
3581 		       "#inodes per group too big: %lu",
3582 		       sbi->s_inodes_per_group);
3583 		goto failed_mount;
3584 	}
3585 
3586 	/* Do we have standard group size of clustersize * 8 blocks ? */
3587 	if (sbi->s_blocks_per_group == clustersize << 3)
3588 		set_opt2(sb, STD_GROUP_SIZE);
3589 
3590 	/*
3591 	 * Test whether we have more sectors than will fit in sector_t,
3592 	 * and whether the max offset is addressable by the page cache.
3593 	 */
3594 	err = generic_check_addressable(sb->s_blocksize_bits,
3595 					ext4_blocks_count(es));
3596 	if (err) {
3597 		ext4_msg(sb, KERN_ERR, "filesystem"
3598 			 " too large to mount safely on this system");
3599 		if (sizeof(sector_t) < 8)
3600 			ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled");
3601 		goto failed_mount;
3602 	}
3603 
3604 	if (EXT4_BLOCKS_PER_GROUP(sb) == 0)
3605 		goto cantfind_ext4;
3606 
3607 	/* check blocks count against device size */
3608 	blocks_count = sb->s_bdev->bd_inode->i_size >> sb->s_blocksize_bits;
3609 	if (blocks_count && ext4_blocks_count(es) > blocks_count) {
3610 		ext4_msg(sb, KERN_WARNING, "bad geometry: block count %llu "
3611 		       "exceeds size of device (%llu blocks)",
3612 		       ext4_blocks_count(es), blocks_count);
3613 		goto failed_mount;
3614 	}
3615 
3616 	/*
3617 	 * It makes no sense for the first data block to be beyond the end
3618 	 * of the filesystem.
3619 	 */
3620 	if (le32_to_cpu(es->s_first_data_block) >= ext4_blocks_count(es)) {
3621 		ext4_msg(sb, KERN_WARNING, "bad geometry: first data "
3622 			 "block %u is beyond end of filesystem (%llu)",
3623 			 le32_to_cpu(es->s_first_data_block),
3624 			 ext4_blocks_count(es));
3625 		goto failed_mount;
3626 	}
3627 	blocks_count = (ext4_blocks_count(es) -
3628 			le32_to_cpu(es->s_first_data_block) +
3629 			EXT4_BLOCKS_PER_GROUP(sb) - 1);
3630 	do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
3631 	if (blocks_count > ((uint64_t)1<<32) - EXT4_DESC_PER_BLOCK(sb)) {
3632 		ext4_msg(sb, KERN_WARNING, "groups count too large: %u "
3633 		       "(block count %llu, first data block %u, "
3634 		       "blocks per group %lu)", sbi->s_groups_count,
3635 		       ext4_blocks_count(es),
3636 		       le32_to_cpu(es->s_first_data_block),
3637 		       EXT4_BLOCKS_PER_GROUP(sb));
3638 		goto failed_mount;
3639 	}
3640 	sbi->s_groups_count = blocks_count;
3641 	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
3642 			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
3643 	db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
3644 		   EXT4_DESC_PER_BLOCK(sb);
3645 	sbi->s_group_desc = ext4_kvmalloc(db_count *
3646 					  sizeof(struct buffer_head *),
3647 					  GFP_KERNEL);
3648 	if (sbi->s_group_desc == NULL) {
3649 		ext4_msg(sb, KERN_ERR, "not enough memory");
3650 		ret = -ENOMEM;
3651 		goto failed_mount;
3652 	}
3653 
3654 	bgl_lock_init(sbi->s_blockgroup_lock);
3655 
3656 	for (i = 0; i < db_count; i++) {
3657 		block = descriptor_loc(sb, logical_sb_block, i);
3658 		sbi->s_group_desc[i] = sb_bread_unmovable(sb, block);
3659 		if (!sbi->s_group_desc[i]) {
3660 			ext4_msg(sb, KERN_ERR,
3661 			       "can't read group descriptor %d", i);
3662 			db_count = i;
3663 			goto failed_mount2;
3664 		}
3665 	}
3666 	if (!ext4_check_descriptors(sb, &first_not_zeroed)) {
3667 		ext4_msg(sb, KERN_ERR, "group descriptors corrupted!");
3668 		ret = -EFSCORRUPTED;
3669 		goto failed_mount2;
3670 	}
3671 
3672 	sbi->s_gdb_count = db_count;
3673 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
3674 	spin_lock_init(&sbi->s_next_gen_lock);
3675 
3676 	setup_timer(&sbi->s_err_report, print_daily_error_info,
3677 		(unsigned long) sb);
3678 
3679 	/* Register extent status tree shrinker */
3680 	if (ext4_es_register_shrinker(sbi))
3681 		goto failed_mount3;
3682 
3683 	sbi->s_stripe = ext4_get_stripe_size(sbi);
3684 	sbi->s_extent_max_zeroout_kb = 32;
3685 
3686 	/*
3687 	 * set up enough so that it can read an inode
3688 	 */
3689 	sb->s_op = &ext4_sops;
3690 	sb->s_export_op = &ext4_export_ops;
3691 	sb->s_xattr = ext4_xattr_handlers;
3692 #ifdef CONFIG_QUOTA
3693 	sb->dq_op = &ext4_quota_operations;
3694 	if (ext4_has_feature_quota(sb))
3695 		sb->s_qcop = &dquot_quotactl_sysfile_ops;
3696 	else
3697 		sb->s_qcop = &ext4_qctl_operations;
3698 	sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP | QTYPE_MASK_PRJ;
3699 #endif
3700 	memcpy(sb->s_uuid, es->s_uuid, sizeof(es->s_uuid));
3701 
3702 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
3703 	mutex_init(&sbi->s_orphan_lock);
3704 
3705 	sb->s_root = NULL;
3706 
3707 	needs_recovery = (es->s_last_orphan != 0 ||
3708 			  ext4_has_feature_journal_needs_recovery(sb));
3709 
3710 	if (ext4_has_feature_mmp(sb) && !(sb->s_flags & MS_RDONLY))
3711 		if (ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block)))
3712 			goto failed_mount3a;
3713 
3714 	/*
3715 	 * The first inode we look at is the journal inode.  Don't try
3716 	 * root first: it may be modified in the journal!
3717 	 */
3718 	if (!test_opt(sb, NOLOAD) && ext4_has_feature_journal(sb)) {
3719 		if (ext4_load_journal(sb, es, journal_devnum))
3720 			goto failed_mount3a;
3721 	} else if (test_opt(sb, NOLOAD) && !(sb->s_flags & MS_RDONLY) &&
3722 		   ext4_has_feature_journal_needs_recovery(sb)) {
3723 		ext4_msg(sb, KERN_ERR, "required journal recovery "
3724 		       "suppressed and not mounted read-only");
3725 		goto failed_mount_wq;
3726 	} else {
3727 		/* Nojournal mode, all journal mount options are illegal */
3728 		if (test_opt2(sb, EXPLICIT_JOURNAL_CHECKSUM)) {
3729 			ext4_msg(sb, KERN_ERR, "can't mount with "
3730 				 "journal_checksum, fs mounted w/o journal");
3731 			goto failed_mount_wq;
3732 		}
3733 		if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
3734 			ext4_msg(sb, KERN_ERR, "can't mount with "
3735 				 "journal_async_commit, fs mounted w/o journal");
3736 			goto failed_mount_wq;
3737 		}
3738 		if (sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ) {
3739 			ext4_msg(sb, KERN_ERR, "can't mount with "
3740 				 "commit=%lu, fs mounted w/o journal",
3741 				 sbi->s_commit_interval / HZ);
3742 			goto failed_mount_wq;
3743 		}
3744 		if (EXT4_MOUNT_DATA_FLAGS &
3745 		    (sbi->s_mount_opt ^ sbi->s_def_mount_opt)) {
3746 			ext4_msg(sb, KERN_ERR, "can't mount with "
3747 				 "data=, fs mounted w/o journal");
3748 			goto failed_mount_wq;
3749 		}
3750 		sbi->s_def_mount_opt &= EXT4_MOUNT_JOURNAL_CHECKSUM;
3751 		clear_opt(sb, JOURNAL_CHECKSUM);
3752 		clear_opt(sb, DATA_FLAGS);
3753 		sbi->s_journal = NULL;
3754 		needs_recovery = 0;
3755 		goto no_journal;
3756 	}
3757 
3758 	if (ext4_has_feature_64bit(sb) &&
3759 	    !jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
3760 				       JBD2_FEATURE_INCOMPAT_64BIT)) {
3761 		ext4_msg(sb, KERN_ERR, "Failed to set 64-bit journal feature");
3762 		goto failed_mount_wq;
3763 	}
3764 
3765 	if (!set_journal_csum_feature_set(sb)) {
3766 		ext4_msg(sb, KERN_ERR, "Failed to set journal checksum "
3767 			 "feature set");
3768 		goto failed_mount_wq;
3769 	}
3770 
3771 	/* We have now updated the journal if required, so we can
3772 	 * validate the data journaling mode. */
3773 	switch (test_opt(sb, DATA_FLAGS)) {
3774 	case 0:
3775 		/* No mode set, assume a default based on the journal
3776 		 * capabilities: ORDERED_DATA if the journal can
3777 		 * cope, else JOURNAL_DATA
3778 		 */
3779 		if (jbd2_journal_check_available_features
3780 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE))
3781 			set_opt(sb, ORDERED_DATA);
3782 		else
3783 			set_opt(sb, JOURNAL_DATA);
3784 		break;
3785 
3786 	case EXT4_MOUNT_ORDERED_DATA:
3787 	case EXT4_MOUNT_WRITEBACK_DATA:
3788 		if (!jbd2_journal_check_available_features
3789 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
3790 			ext4_msg(sb, KERN_ERR, "Journal does not support "
3791 			       "requested data journaling mode");
3792 			goto failed_mount_wq;
3793 		}
3794 	default:
3795 		break;
3796 	}
3797 	set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
3798 
3799 	sbi->s_journal->j_commit_callback = ext4_journal_commit_callback;
3800 
3801 no_journal:
3802 	sbi->s_mb_cache = ext4_xattr_create_cache();
3803 	if (!sbi->s_mb_cache) {
3804 		ext4_msg(sb, KERN_ERR, "Failed to create an mb_cache");
3805 		goto failed_mount_wq;
3806 	}
3807 
3808 	if ((DUMMY_ENCRYPTION_ENABLED(sbi) || ext4_has_feature_encrypt(sb)) &&
3809 	    (blocksize != PAGE_CACHE_SIZE)) {
3810 		ext4_msg(sb, KERN_ERR,
3811 			 "Unsupported blocksize for fs encryption");
3812 		goto failed_mount_wq;
3813 	}
3814 
3815 	if (DUMMY_ENCRYPTION_ENABLED(sbi) && !(sb->s_flags & MS_RDONLY) &&
3816 	    !ext4_has_feature_encrypt(sb)) {
3817 		ext4_set_feature_encrypt(sb);
3818 		ext4_commit_super(sb, 1);
3819 	}
3820 
3821 	/*
3822 	 * Get the # of file system overhead blocks from the
3823 	 * superblock if present.
3824 	 */
3825 	if (es->s_overhead_clusters)
3826 		sbi->s_overhead = le32_to_cpu(es->s_overhead_clusters);
3827 	else {
3828 		err = ext4_calculate_overhead(sb);
3829 		if (err)
3830 			goto failed_mount_wq;
3831 	}
3832 
3833 	/*
3834 	 * The maximum number of concurrent works can be high and
3835 	 * concurrency isn't really necessary.  Limit it to 1.
3836 	 */
3837 	EXT4_SB(sb)->rsv_conversion_wq =
3838 		alloc_workqueue("ext4-rsv-conversion", WQ_MEM_RECLAIM | WQ_UNBOUND, 1);
3839 	if (!EXT4_SB(sb)->rsv_conversion_wq) {
3840 		printk(KERN_ERR "EXT4-fs: failed to create workqueue\n");
3841 		ret = -ENOMEM;
3842 		goto failed_mount4;
3843 	}
3844 
3845 	/*
3846 	 * The jbd2_journal_load will have done any necessary log recovery,
3847 	 * so we can safely mount the rest of the filesystem now.
3848 	 */
3849 
3850 	root = ext4_iget(sb, EXT4_ROOT_INO);
3851 	if (IS_ERR(root)) {
3852 		ext4_msg(sb, KERN_ERR, "get root inode failed");
3853 		ret = PTR_ERR(root);
3854 		root = NULL;
3855 		goto failed_mount4;
3856 	}
3857 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
3858 		ext4_msg(sb, KERN_ERR, "corrupt root inode, run e2fsck");
3859 		iput(root);
3860 		goto failed_mount4;
3861 	}
3862 	sb->s_root = d_make_root(root);
3863 	if (!sb->s_root) {
3864 		ext4_msg(sb, KERN_ERR, "get root dentry failed");
3865 		ret = -ENOMEM;
3866 		goto failed_mount4;
3867 	}
3868 
3869 	if (ext4_setup_super(sb, es, sb->s_flags & MS_RDONLY))
3870 		sb->s_flags |= MS_RDONLY;
3871 
3872 	/* determine the minimum size of new large inodes, if present */
3873 	if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
3874 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
3875 						     EXT4_GOOD_OLD_INODE_SIZE;
3876 		if (ext4_has_feature_extra_isize(sb)) {
3877 			if (sbi->s_want_extra_isize <
3878 			    le16_to_cpu(es->s_want_extra_isize))
3879 				sbi->s_want_extra_isize =
3880 					le16_to_cpu(es->s_want_extra_isize);
3881 			if (sbi->s_want_extra_isize <
3882 			    le16_to_cpu(es->s_min_extra_isize))
3883 				sbi->s_want_extra_isize =
3884 					le16_to_cpu(es->s_min_extra_isize);
3885 		}
3886 	}
3887 	/* Check if enough inode space is available */
3888 	if (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize >
3889 							sbi->s_inode_size) {
3890 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
3891 						       EXT4_GOOD_OLD_INODE_SIZE;
3892 		ext4_msg(sb, KERN_INFO, "required extra inode space not"
3893 			 "available");
3894 	}
3895 
3896 	ext4_set_resv_clusters(sb);
3897 
3898 	err = ext4_setup_system_zone(sb);
3899 	if (err) {
3900 		ext4_msg(sb, KERN_ERR, "failed to initialize system "
3901 			 "zone (%d)", err);
3902 		goto failed_mount4a;
3903 	}
3904 
3905 	ext4_ext_init(sb);
3906 	err = ext4_mb_init(sb);
3907 	if (err) {
3908 		ext4_msg(sb, KERN_ERR, "failed to initialize mballoc (%d)",
3909 			 err);
3910 		goto failed_mount5;
3911 	}
3912 
3913 	block = ext4_count_free_clusters(sb);
3914 	ext4_free_blocks_count_set(sbi->s_es,
3915 				   EXT4_C2B(sbi, block));
3916 	err = percpu_counter_init(&sbi->s_freeclusters_counter, block,
3917 				  GFP_KERNEL);
3918 	if (!err) {
3919 		unsigned long freei = ext4_count_free_inodes(sb);
3920 		sbi->s_es->s_free_inodes_count = cpu_to_le32(freei);
3921 		err = percpu_counter_init(&sbi->s_freeinodes_counter, freei,
3922 					  GFP_KERNEL);
3923 	}
3924 	if (!err)
3925 		err = percpu_counter_init(&sbi->s_dirs_counter,
3926 					  ext4_count_dirs(sb), GFP_KERNEL);
3927 	if (!err)
3928 		err = percpu_counter_init(&sbi->s_dirtyclusters_counter, 0,
3929 					  GFP_KERNEL);
3930 	if (err) {
3931 		ext4_msg(sb, KERN_ERR, "insufficient memory");
3932 		goto failed_mount6;
3933 	}
3934 
3935 	if (ext4_has_feature_flex_bg(sb))
3936 		if (!ext4_fill_flex_info(sb)) {
3937 			ext4_msg(sb, KERN_ERR,
3938 			       "unable to initialize "
3939 			       "flex_bg meta info!");
3940 			goto failed_mount6;
3941 		}
3942 
3943 	err = ext4_register_li_request(sb, first_not_zeroed);
3944 	if (err)
3945 		goto failed_mount6;
3946 
3947 	err = ext4_register_sysfs(sb);
3948 	if (err)
3949 		goto failed_mount7;
3950 
3951 #ifdef CONFIG_QUOTA
3952 	/* Enable quota usage during mount. */
3953 	if (ext4_has_feature_quota(sb) && !(sb->s_flags & MS_RDONLY)) {
3954 		err = ext4_enable_quotas(sb);
3955 		if (err)
3956 			goto failed_mount8;
3957 	}
3958 #endif  /* CONFIG_QUOTA */
3959 
3960 	EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
3961 	ext4_orphan_cleanup(sb, es);
3962 	EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
3963 	if (needs_recovery) {
3964 		ext4_msg(sb, KERN_INFO, "recovery complete");
3965 		ext4_mark_recovery_complete(sb, es);
3966 	}
3967 	if (EXT4_SB(sb)->s_journal) {
3968 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
3969 			descr = " journalled data mode";
3970 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
3971 			descr = " ordered data mode";
3972 		else
3973 			descr = " writeback data mode";
3974 	} else
3975 		descr = "out journal";
3976 
3977 	if (test_opt(sb, DISCARD)) {
3978 		struct request_queue *q = bdev_get_queue(sb->s_bdev);
3979 		if (!blk_queue_discard(q))
3980 			ext4_msg(sb, KERN_WARNING,
3981 				 "mounting with \"discard\" option, but "
3982 				 "the device does not support discard");
3983 	}
3984 
3985 	if (___ratelimit(&ext4_mount_msg_ratelimit, "EXT4-fs mount"))
3986 		ext4_msg(sb, KERN_INFO, "mounted filesystem with%s. "
3987 			 "Opts: %s%s%s", descr, sbi->s_es->s_mount_opts,
3988 			 *sbi->s_es->s_mount_opts ? "; " : "", orig_data);
3989 
3990 	if (es->s_error_count)
3991 		mod_timer(&sbi->s_err_report, jiffies + 300*HZ); /* 5 minutes */
3992 
3993 	/* Enable message ratelimiting. Default is 10 messages per 5 secs. */
3994 	ratelimit_state_init(&sbi->s_err_ratelimit_state, 5 * HZ, 10);
3995 	ratelimit_state_init(&sbi->s_warning_ratelimit_state, 5 * HZ, 10);
3996 	ratelimit_state_init(&sbi->s_msg_ratelimit_state, 5 * HZ, 10);
3997 
3998 	kfree(orig_data);
3999 	return 0;
4000 
4001 cantfind_ext4:
4002 	if (!silent)
4003 		ext4_msg(sb, KERN_ERR, "VFS: Can't find ext4 filesystem");
4004 	goto failed_mount;
4005 
4006 #ifdef CONFIG_QUOTA
4007 failed_mount8:
4008 	ext4_unregister_sysfs(sb);
4009 #endif
4010 failed_mount7:
4011 	ext4_unregister_li_request(sb);
4012 failed_mount6:
4013 	ext4_mb_release(sb);
4014 	if (sbi->s_flex_groups)
4015 		kvfree(sbi->s_flex_groups);
4016 	percpu_counter_destroy(&sbi->s_freeclusters_counter);
4017 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
4018 	percpu_counter_destroy(&sbi->s_dirs_counter);
4019 	percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
4020 failed_mount5:
4021 	ext4_ext_release(sb);
4022 	ext4_release_system_zone(sb);
4023 failed_mount4a:
4024 	dput(sb->s_root);
4025 	sb->s_root = NULL;
4026 failed_mount4:
4027 	ext4_msg(sb, KERN_ERR, "mount failed");
4028 	if (EXT4_SB(sb)->rsv_conversion_wq)
4029 		destroy_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
4030 failed_mount_wq:
4031 	if (sbi->s_mb_cache) {
4032 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
4033 		sbi->s_mb_cache = NULL;
4034 	}
4035 	if (sbi->s_journal) {
4036 		jbd2_journal_destroy(sbi->s_journal);
4037 		sbi->s_journal = NULL;
4038 	}
4039 failed_mount3a:
4040 	ext4_es_unregister_shrinker(sbi);
4041 failed_mount3:
4042 	del_timer_sync(&sbi->s_err_report);
4043 	if (sbi->s_mmp_tsk)
4044 		kthread_stop(sbi->s_mmp_tsk);
4045 failed_mount2:
4046 	for (i = 0; i < db_count; i++)
4047 		brelse(sbi->s_group_desc[i]);
4048 	kvfree(sbi->s_group_desc);
4049 failed_mount:
4050 	if (sbi->s_chksum_driver)
4051 		crypto_free_shash(sbi->s_chksum_driver);
4052 #ifdef CONFIG_QUOTA
4053 	for (i = 0; i < EXT4_MAXQUOTAS; i++)
4054 		kfree(sbi->s_qf_names[i]);
4055 #endif
4056 	ext4_blkdev_remove(sbi);
4057 	brelse(bh);
4058 out_fail:
4059 	sb->s_fs_info = NULL;
4060 	kfree(sbi->s_blockgroup_lock);
4061 	kfree(sbi);
4062 out_free_orig:
4063 	kfree(orig_data);
4064 	return err ? err : ret;
4065 }
4066 
4067 /*
4068  * Setup any per-fs journal parameters now.  We'll do this both on
4069  * initial mount, once the journal has been initialised but before we've
4070  * done any recovery; and again on any subsequent remount.
4071  */
4072 static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
4073 {
4074 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4075 
4076 	journal->j_commit_interval = sbi->s_commit_interval;
4077 	journal->j_min_batch_time = sbi->s_min_batch_time;
4078 	journal->j_max_batch_time = sbi->s_max_batch_time;
4079 
4080 	write_lock(&journal->j_state_lock);
4081 	if (test_opt(sb, BARRIER))
4082 		journal->j_flags |= JBD2_BARRIER;
4083 	else
4084 		journal->j_flags &= ~JBD2_BARRIER;
4085 	if (test_opt(sb, DATA_ERR_ABORT))
4086 		journal->j_flags |= JBD2_ABORT_ON_SYNCDATA_ERR;
4087 	else
4088 		journal->j_flags &= ~JBD2_ABORT_ON_SYNCDATA_ERR;
4089 	write_unlock(&journal->j_state_lock);
4090 }
4091 
4092 static journal_t *ext4_get_journal(struct super_block *sb,
4093 				   unsigned int journal_inum)
4094 {
4095 	struct inode *journal_inode;
4096 	journal_t *journal;
4097 
4098 	BUG_ON(!ext4_has_feature_journal(sb));
4099 
4100 	/* First, test for the existence of a valid inode on disk.  Bad
4101 	 * things happen if we iget() an unused inode, as the subsequent
4102 	 * iput() will try to delete it. */
4103 
4104 	journal_inode = ext4_iget(sb, journal_inum);
4105 	if (IS_ERR(journal_inode)) {
4106 		ext4_msg(sb, KERN_ERR, "no journal found");
4107 		return NULL;
4108 	}
4109 	if (!journal_inode->i_nlink) {
4110 		make_bad_inode(journal_inode);
4111 		iput(journal_inode);
4112 		ext4_msg(sb, KERN_ERR, "journal inode is deleted");
4113 		return NULL;
4114 	}
4115 
4116 	jbd_debug(2, "Journal inode found at %p: %lld bytes\n",
4117 		  journal_inode, journal_inode->i_size);
4118 	if (!S_ISREG(journal_inode->i_mode)) {
4119 		ext4_msg(sb, KERN_ERR, "invalid journal inode");
4120 		iput(journal_inode);
4121 		return NULL;
4122 	}
4123 
4124 	journal = jbd2_journal_init_inode(journal_inode);
4125 	if (!journal) {
4126 		ext4_msg(sb, KERN_ERR, "Could not load journal inode");
4127 		iput(journal_inode);
4128 		return NULL;
4129 	}
4130 	journal->j_private = sb;
4131 	ext4_init_journal_params(sb, journal);
4132 	return journal;
4133 }
4134 
4135 static journal_t *ext4_get_dev_journal(struct super_block *sb,
4136 				       dev_t j_dev)
4137 {
4138 	struct buffer_head *bh;
4139 	journal_t *journal;
4140 	ext4_fsblk_t start;
4141 	ext4_fsblk_t len;
4142 	int hblock, blocksize;
4143 	ext4_fsblk_t sb_block;
4144 	unsigned long offset;
4145 	struct ext4_super_block *es;
4146 	struct block_device *bdev;
4147 
4148 	BUG_ON(!ext4_has_feature_journal(sb));
4149 
4150 	bdev = ext4_blkdev_get(j_dev, sb);
4151 	if (bdev == NULL)
4152 		return NULL;
4153 
4154 	blocksize = sb->s_blocksize;
4155 	hblock = bdev_logical_block_size(bdev);
4156 	if (blocksize < hblock) {
4157 		ext4_msg(sb, KERN_ERR,
4158 			"blocksize too small for journal device");
4159 		goto out_bdev;
4160 	}
4161 
4162 	sb_block = EXT4_MIN_BLOCK_SIZE / blocksize;
4163 	offset = EXT4_MIN_BLOCK_SIZE % blocksize;
4164 	set_blocksize(bdev, blocksize);
4165 	if (!(bh = __bread(bdev, sb_block, blocksize))) {
4166 		ext4_msg(sb, KERN_ERR, "couldn't read superblock of "
4167 		       "external journal");
4168 		goto out_bdev;
4169 	}
4170 
4171 	es = (struct ext4_super_block *) (bh->b_data + offset);
4172 	if ((le16_to_cpu(es->s_magic) != EXT4_SUPER_MAGIC) ||
4173 	    !(le32_to_cpu(es->s_feature_incompat) &
4174 	      EXT4_FEATURE_INCOMPAT_JOURNAL_DEV)) {
4175 		ext4_msg(sb, KERN_ERR, "external journal has "
4176 					"bad superblock");
4177 		brelse(bh);
4178 		goto out_bdev;
4179 	}
4180 
4181 	if ((le32_to_cpu(es->s_feature_ro_compat) &
4182 	     EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
4183 	    es->s_checksum != ext4_superblock_csum(sb, es)) {
4184 		ext4_msg(sb, KERN_ERR, "external journal has "
4185 				       "corrupt superblock");
4186 		brelse(bh);
4187 		goto out_bdev;
4188 	}
4189 
4190 	if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
4191 		ext4_msg(sb, KERN_ERR, "journal UUID does not match");
4192 		brelse(bh);
4193 		goto out_bdev;
4194 	}
4195 
4196 	len = ext4_blocks_count(es);
4197 	start = sb_block + 1;
4198 	brelse(bh);	/* we're done with the superblock */
4199 
4200 	journal = jbd2_journal_init_dev(bdev, sb->s_bdev,
4201 					start, len, blocksize);
4202 	if (!journal) {
4203 		ext4_msg(sb, KERN_ERR, "failed to create device journal");
4204 		goto out_bdev;
4205 	}
4206 	journal->j_private = sb;
4207 	ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &journal->j_sb_buffer);
4208 	wait_on_buffer(journal->j_sb_buffer);
4209 	if (!buffer_uptodate(journal->j_sb_buffer)) {
4210 		ext4_msg(sb, KERN_ERR, "I/O error on journal device");
4211 		goto out_journal;
4212 	}
4213 	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
4214 		ext4_msg(sb, KERN_ERR, "External journal has more than one "
4215 					"user (unsupported) - %d",
4216 			be32_to_cpu(journal->j_superblock->s_nr_users));
4217 		goto out_journal;
4218 	}
4219 	EXT4_SB(sb)->journal_bdev = bdev;
4220 	ext4_init_journal_params(sb, journal);
4221 	return journal;
4222 
4223 out_journal:
4224 	jbd2_journal_destroy(journal);
4225 out_bdev:
4226 	ext4_blkdev_put(bdev);
4227 	return NULL;
4228 }
4229 
4230 static int ext4_load_journal(struct super_block *sb,
4231 			     struct ext4_super_block *es,
4232 			     unsigned long journal_devnum)
4233 {
4234 	journal_t *journal;
4235 	unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
4236 	dev_t journal_dev;
4237 	int err = 0;
4238 	int really_read_only;
4239 
4240 	BUG_ON(!ext4_has_feature_journal(sb));
4241 
4242 	if (journal_devnum &&
4243 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
4244 		ext4_msg(sb, KERN_INFO, "external journal device major/minor "
4245 			"numbers have changed");
4246 		journal_dev = new_decode_dev(journal_devnum);
4247 	} else
4248 		journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));
4249 
4250 	really_read_only = bdev_read_only(sb->s_bdev);
4251 
4252 	/*
4253 	 * Are we loading a blank journal or performing recovery after a
4254 	 * crash?  For recovery, we need to check in advance whether we
4255 	 * can get read-write access to the device.
4256 	 */
4257 	if (ext4_has_feature_journal_needs_recovery(sb)) {
4258 		if (sb->s_flags & MS_RDONLY) {
4259 			ext4_msg(sb, KERN_INFO, "INFO: recovery "
4260 					"required on readonly filesystem");
4261 			if (really_read_only) {
4262 				ext4_msg(sb, KERN_ERR, "write access "
4263 					"unavailable, cannot proceed");
4264 				return -EROFS;
4265 			}
4266 			ext4_msg(sb, KERN_INFO, "write access will "
4267 			       "be enabled during recovery");
4268 		}
4269 	}
4270 
4271 	if (journal_inum && journal_dev) {
4272 		ext4_msg(sb, KERN_ERR, "filesystem has both journal "
4273 		       "and inode journals!");
4274 		return -EINVAL;
4275 	}
4276 
4277 	if (journal_inum) {
4278 		if (!(journal = ext4_get_journal(sb, journal_inum)))
4279 			return -EINVAL;
4280 	} else {
4281 		if (!(journal = ext4_get_dev_journal(sb, journal_dev)))
4282 			return -EINVAL;
4283 	}
4284 
4285 	if (!(journal->j_flags & JBD2_BARRIER))
4286 		ext4_msg(sb, KERN_INFO, "barriers disabled");
4287 
4288 	if (!ext4_has_feature_journal_needs_recovery(sb))
4289 		err = jbd2_journal_wipe(journal, !really_read_only);
4290 	if (!err) {
4291 		char *save = kmalloc(EXT4_S_ERR_LEN, GFP_KERNEL);
4292 		if (save)
4293 			memcpy(save, ((char *) es) +
4294 			       EXT4_S_ERR_START, EXT4_S_ERR_LEN);
4295 		err = jbd2_journal_load(journal);
4296 		if (save)
4297 			memcpy(((char *) es) + EXT4_S_ERR_START,
4298 			       save, EXT4_S_ERR_LEN);
4299 		kfree(save);
4300 	}
4301 
4302 	if (err) {
4303 		ext4_msg(sb, KERN_ERR, "error loading journal");
4304 		jbd2_journal_destroy(journal);
4305 		return err;
4306 	}
4307 
4308 	EXT4_SB(sb)->s_journal = journal;
4309 	ext4_clear_journal_err(sb, es);
4310 
4311 	if (!really_read_only && journal_devnum &&
4312 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
4313 		es->s_journal_dev = cpu_to_le32(journal_devnum);
4314 
4315 		/* Make sure we flush the recovery flag to disk. */
4316 		ext4_commit_super(sb, 1);
4317 	}
4318 
4319 	return 0;
4320 }
4321 
4322 static int ext4_commit_super(struct super_block *sb, int sync)
4323 {
4324 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
4325 	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
4326 	int error = 0;
4327 
4328 	if (!sbh || block_device_ejected(sb))
4329 		return error;
4330 	if (buffer_write_io_error(sbh)) {
4331 		/*
4332 		 * Oh, dear.  A previous attempt to write the
4333 		 * superblock failed.  This could happen because the
4334 		 * USB device was yanked out.  Or it could happen to
4335 		 * be a transient write error and maybe the block will
4336 		 * be remapped.  Nothing we can do but to retry the
4337 		 * write and hope for the best.
4338 		 */
4339 		ext4_msg(sb, KERN_ERR, "previous I/O error to "
4340 		       "superblock detected");
4341 		clear_buffer_write_io_error(sbh);
4342 		set_buffer_uptodate(sbh);
4343 	}
4344 	/*
4345 	 * If the file system is mounted read-only, don't update the
4346 	 * superblock write time.  This avoids updating the superblock
4347 	 * write time when we are mounting the root file system
4348 	 * read/only but we need to replay the journal; at that point,
4349 	 * for people who are east of GMT and who make their clock
4350 	 * tick in localtime for Windows bug-for-bug compatibility,
4351 	 * the clock is set in the future, and this will cause e2fsck
4352 	 * to complain and force a full file system check.
4353 	 */
4354 	if (!(sb->s_flags & MS_RDONLY))
4355 		es->s_wtime = cpu_to_le32(get_seconds());
4356 	if (sb->s_bdev->bd_part)
4357 		es->s_kbytes_written =
4358 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written +
4359 			    ((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
4360 			      EXT4_SB(sb)->s_sectors_written_start) >> 1));
4361 	else
4362 		es->s_kbytes_written =
4363 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written);
4364 	if (percpu_counter_initialized(&EXT4_SB(sb)->s_freeclusters_counter))
4365 		ext4_free_blocks_count_set(es,
4366 			EXT4_C2B(EXT4_SB(sb), percpu_counter_sum_positive(
4367 				&EXT4_SB(sb)->s_freeclusters_counter)));
4368 	if (percpu_counter_initialized(&EXT4_SB(sb)->s_freeinodes_counter))
4369 		es->s_free_inodes_count =
4370 			cpu_to_le32(percpu_counter_sum_positive(
4371 				&EXT4_SB(sb)->s_freeinodes_counter));
4372 	BUFFER_TRACE(sbh, "marking dirty");
4373 	ext4_superblock_csum_set(sb);
4374 	mark_buffer_dirty(sbh);
4375 	if (sync) {
4376 		error = __sync_dirty_buffer(sbh,
4377 			test_opt(sb, BARRIER) ? WRITE_FUA : WRITE_SYNC);
4378 		if (error)
4379 			return error;
4380 
4381 		error = buffer_write_io_error(sbh);
4382 		if (error) {
4383 			ext4_msg(sb, KERN_ERR, "I/O error while writing "
4384 			       "superblock");
4385 			clear_buffer_write_io_error(sbh);
4386 			set_buffer_uptodate(sbh);
4387 		}
4388 	}
4389 	return error;
4390 }
4391 
4392 /*
4393  * Have we just finished recovery?  If so, and if we are mounting (or
4394  * remounting) the filesystem readonly, then we will end up with a
4395  * consistent fs on disk.  Record that fact.
4396  */
4397 static void ext4_mark_recovery_complete(struct super_block *sb,
4398 					struct ext4_super_block *es)
4399 {
4400 	journal_t *journal = EXT4_SB(sb)->s_journal;
4401 
4402 	if (!ext4_has_feature_journal(sb)) {
4403 		BUG_ON(journal != NULL);
4404 		return;
4405 	}
4406 	jbd2_journal_lock_updates(journal);
4407 	if (jbd2_journal_flush(journal) < 0)
4408 		goto out;
4409 
4410 	if (ext4_has_feature_journal_needs_recovery(sb) &&
4411 	    sb->s_flags & MS_RDONLY) {
4412 		ext4_clear_feature_journal_needs_recovery(sb);
4413 		ext4_commit_super(sb, 1);
4414 	}
4415 
4416 out:
4417 	jbd2_journal_unlock_updates(journal);
4418 }
4419 
4420 /*
4421  * If we are mounting (or read-write remounting) a filesystem whose journal
4422  * has recorded an error from a previous lifetime, move that error to the
4423  * main filesystem now.
4424  */
4425 static void ext4_clear_journal_err(struct super_block *sb,
4426 				   struct ext4_super_block *es)
4427 {
4428 	journal_t *journal;
4429 	int j_errno;
4430 	const char *errstr;
4431 
4432 	BUG_ON(!ext4_has_feature_journal(sb));
4433 
4434 	journal = EXT4_SB(sb)->s_journal;
4435 
4436 	/*
4437 	 * Now check for any error status which may have been recorded in the
4438 	 * journal by a prior ext4_error() or ext4_abort()
4439 	 */
4440 
4441 	j_errno = jbd2_journal_errno(journal);
4442 	if (j_errno) {
4443 		char nbuf[16];
4444 
4445 		errstr = ext4_decode_error(sb, j_errno, nbuf);
4446 		ext4_warning(sb, "Filesystem error recorded "
4447 			     "from previous mount: %s", errstr);
4448 		ext4_warning(sb, "Marking fs in need of filesystem check.");
4449 
4450 		EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
4451 		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
4452 		ext4_commit_super(sb, 1);
4453 
4454 		jbd2_journal_clear_err(journal);
4455 		jbd2_journal_update_sb_errno(journal);
4456 	}
4457 }
4458 
4459 /*
4460  * Force the running and committing transactions to commit,
4461  * and wait on the commit.
4462  */
4463 int ext4_force_commit(struct super_block *sb)
4464 {
4465 	journal_t *journal;
4466 
4467 	if (sb->s_flags & MS_RDONLY)
4468 		return 0;
4469 
4470 	journal = EXT4_SB(sb)->s_journal;
4471 	return ext4_journal_force_commit(journal);
4472 }
4473 
4474 static int ext4_sync_fs(struct super_block *sb, int wait)
4475 {
4476 	int ret = 0;
4477 	tid_t target;
4478 	bool needs_barrier = false;
4479 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4480 
4481 	trace_ext4_sync_fs(sb, wait);
4482 	flush_workqueue(sbi->rsv_conversion_wq);
4483 	/*
4484 	 * Writeback quota in non-journalled quota case - journalled quota has
4485 	 * no dirty dquots
4486 	 */
4487 	dquot_writeback_dquots(sb, -1);
4488 	/*
4489 	 * Data writeback is possible w/o journal transaction, so barrier must
4490 	 * being sent at the end of the function. But we can skip it if
4491 	 * transaction_commit will do it for us.
4492 	 */
4493 	if (sbi->s_journal) {
4494 		target = jbd2_get_latest_transaction(sbi->s_journal);
4495 		if (wait && sbi->s_journal->j_flags & JBD2_BARRIER &&
4496 		    !jbd2_trans_will_send_data_barrier(sbi->s_journal, target))
4497 			needs_barrier = true;
4498 
4499 		if (jbd2_journal_start_commit(sbi->s_journal, &target)) {
4500 			if (wait)
4501 				ret = jbd2_log_wait_commit(sbi->s_journal,
4502 							   target);
4503 		}
4504 	} else if (wait && test_opt(sb, BARRIER))
4505 		needs_barrier = true;
4506 	if (needs_barrier) {
4507 		int err;
4508 		err = blkdev_issue_flush(sb->s_bdev, GFP_KERNEL, NULL);
4509 		if (!ret)
4510 			ret = err;
4511 	}
4512 
4513 	return ret;
4514 }
4515 
4516 /*
4517  * LVM calls this function before a (read-only) snapshot is created.  This
4518  * gives us a chance to flush the journal completely and mark the fs clean.
4519  *
4520  * Note that only this function cannot bring a filesystem to be in a clean
4521  * state independently. It relies on upper layer to stop all data & metadata
4522  * modifications.
4523  */
4524 static int ext4_freeze(struct super_block *sb)
4525 {
4526 	int error = 0;
4527 	journal_t *journal;
4528 
4529 	if (sb->s_flags & MS_RDONLY)
4530 		return 0;
4531 
4532 	journal = EXT4_SB(sb)->s_journal;
4533 
4534 	if (journal) {
4535 		/* Now we set up the journal barrier. */
4536 		jbd2_journal_lock_updates(journal);
4537 
4538 		/*
4539 		 * Don't clear the needs_recovery flag if we failed to
4540 		 * flush the journal.
4541 		 */
4542 		error = jbd2_journal_flush(journal);
4543 		if (error < 0)
4544 			goto out;
4545 
4546 		/* Journal blocked and flushed, clear needs_recovery flag. */
4547 		ext4_clear_feature_journal_needs_recovery(sb);
4548 	}
4549 
4550 	error = ext4_commit_super(sb, 1);
4551 out:
4552 	if (journal)
4553 		/* we rely on upper layer to stop further updates */
4554 		jbd2_journal_unlock_updates(journal);
4555 	return error;
4556 }
4557 
4558 /*
4559  * Called by LVM after the snapshot is done.  We need to reset the RECOVER
4560  * flag here, even though the filesystem is not technically dirty yet.
4561  */
4562 static int ext4_unfreeze(struct super_block *sb)
4563 {
4564 	if (sb->s_flags & MS_RDONLY)
4565 		return 0;
4566 
4567 	if (EXT4_SB(sb)->s_journal) {
4568 		/* Reset the needs_recovery flag before the fs is unlocked. */
4569 		ext4_set_feature_journal_needs_recovery(sb);
4570 	}
4571 
4572 	ext4_commit_super(sb, 1);
4573 	return 0;
4574 }
4575 
4576 /*
4577  * Structure to save mount options for ext4_remount's benefit
4578  */
4579 struct ext4_mount_options {
4580 	unsigned long s_mount_opt;
4581 	unsigned long s_mount_opt2;
4582 	kuid_t s_resuid;
4583 	kgid_t s_resgid;
4584 	unsigned long s_commit_interval;
4585 	u32 s_min_batch_time, s_max_batch_time;
4586 #ifdef CONFIG_QUOTA
4587 	int s_jquota_fmt;
4588 	char *s_qf_names[EXT4_MAXQUOTAS];
4589 #endif
4590 };
4591 
4592 static int ext4_remount(struct super_block *sb, int *flags, char *data)
4593 {
4594 	struct ext4_super_block *es;
4595 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4596 	unsigned long old_sb_flags;
4597 	struct ext4_mount_options old_opts;
4598 	int enable_quota = 0;
4599 	ext4_group_t g;
4600 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
4601 	int err = 0;
4602 #ifdef CONFIG_QUOTA
4603 	int i, j;
4604 #endif
4605 	char *orig_data = kstrdup(data, GFP_KERNEL);
4606 
4607 	/* Store the original options */
4608 	old_sb_flags = sb->s_flags;
4609 	old_opts.s_mount_opt = sbi->s_mount_opt;
4610 	old_opts.s_mount_opt2 = sbi->s_mount_opt2;
4611 	old_opts.s_resuid = sbi->s_resuid;
4612 	old_opts.s_resgid = sbi->s_resgid;
4613 	old_opts.s_commit_interval = sbi->s_commit_interval;
4614 	old_opts.s_min_batch_time = sbi->s_min_batch_time;
4615 	old_opts.s_max_batch_time = sbi->s_max_batch_time;
4616 #ifdef CONFIG_QUOTA
4617 	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
4618 	for (i = 0; i < EXT4_MAXQUOTAS; i++)
4619 		if (sbi->s_qf_names[i]) {
4620 			old_opts.s_qf_names[i] = kstrdup(sbi->s_qf_names[i],
4621 							 GFP_KERNEL);
4622 			if (!old_opts.s_qf_names[i]) {
4623 				for (j = 0; j < i; j++)
4624 					kfree(old_opts.s_qf_names[j]);
4625 				kfree(orig_data);
4626 				return -ENOMEM;
4627 			}
4628 		} else
4629 			old_opts.s_qf_names[i] = NULL;
4630 #endif
4631 	if (sbi->s_journal && sbi->s_journal->j_task->io_context)
4632 		journal_ioprio = sbi->s_journal->j_task->io_context->ioprio;
4633 
4634 	if (!parse_options(data, sb, NULL, &journal_ioprio, 1)) {
4635 		err = -EINVAL;
4636 		goto restore_opts;
4637 	}
4638 
4639 	if ((old_opts.s_mount_opt & EXT4_MOUNT_JOURNAL_CHECKSUM) ^
4640 	    test_opt(sb, JOURNAL_CHECKSUM)) {
4641 		ext4_msg(sb, KERN_ERR, "changing journal_checksum "
4642 			 "during remount not supported; ignoring");
4643 		sbi->s_mount_opt ^= EXT4_MOUNT_JOURNAL_CHECKSUM;
4644 	}
4645 
4646 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
4647 		if (test_opt2(sb, EXPLICIT_DELALLOC)) {
4648 			ext4_msg(sb, KERN_ERR, "can't mount with "
4649 				 "both data=journal and delalloc");
4650 			err = -EINVAL;
4651 			goto restore_opts;
4652 		}
4653 		if (test_opt(sb, DIOREAD_NOLOCK)) {
4654 			ext4_msg(sb, KERN_ERR, "can't mount with "
4655 				 "both data=journal and dioread_nolock");
4656 			err = -EINVAL;
4657 			goto restore_opts;
4658 		}
4659 		if (test_opt(sb, DAX)) {
4660 			ext4_msg(sb, KERN_ERR, "can't mount with "
4661 				 "both data=journal and dax");
4662 			err = -EINVAL;
4663 			goto restore_opts;
4664 		}
4665 	}
4666 
4667 	if ((sbi->s_mount_opt ^ old_opts.s_mount_opt) & EXT4_MOUNT_DAX) {
4668 		ext4_msg(sb, KERN_WARNING, "warning: refusing change of "
4669 			"dax flag with busy inodes while remounting");
4670 		sbi->s_mount_opt ^= EXT4_MOUNT_DAX;
4671 	}
4672 
4673 	if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
4674 		ext4_abort(sb, "Abort forced by user");
4675 
4676 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
4677 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
4678 
4679 	es = sbi->s_es;
4680 
4681 	if (sbi->s_journal) {
4682 		ext4_init_journal_params(sb, sbi->s_journal);
4683 		set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
4684 	}
4685 
4686 	if (*flags & MS_LAZYTIME)
4687 		sb->s_flags |= MS_LAZYTIME;
4688 
4689 	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY)) {
4690 		if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) {
4691 			err = -EROFS;
4692 			goto restore_opts;
4693 		}
4694 
4695 		if (*flags & MS_RDONLY) {
4696 			err = sync_filesystem(sb);
4697 			if (err < 0)
4698 				goto restore_opts;
4699 			err = dquot_suspend(sb, -1);
4700 			if (err < 0)
4701 				goto restore_opts;
4702 
4703 			/*
4704 			 * First of all, the unconditional stuff we have to do
4705 			 * to disable replay of the journal when we next remount
4706 			 */
4707 			sb->s_flags |= MS_RDONLY;
4708 
4709 			/*
4710 			 * OK, test if we are remounting a valid rw partition
4711 			 * readonly, and if so set the rdonly flag and then
4712 			 * mark the partition as valid again.
4713 			 */
4714 			if (!(es->s_state & cpu_to_le16(EXT4_VALID_FS)) &&
4715 			    (sbi->s_mount_state & EXT4_VALID_FS))
4716 				es->s_state = cpu_to_le16(sbi->s_mount_state);
4717 
4718 			if (sbi->s_journal)
4719 				ext4_mark_recovery_complete(sb, es);
4720 		} else {
4721 			/* Make sure we can mount this feature set readwrite */
4722 			if (ext4_has_feature_readonly(sb) ||
4723 			    !ext4_feature_set_ok(sb, 0)) {
4724 				err = -EROFS;
4725 				goto restore_opts;
4726 			}
4727 			/*
4728 			 * Make sure the group descriptor checksums
4729 			 * are sane.  If they aren't, refuse to remount r/w.
4730 			 */
4731 			for (g = 0; g < sbi->s_groups_count; g++) {
4732 				struct ext4_group_desc *gdp =
4733 					ext4_get_group_desc(sb, g, NULL);
4734 
4735 				if (!ext4_group_desc_csum_verify(sb, g, gdp)) {
4736 					ext4_msg(sb, KERN_ERR,
4737 	       "ext4_remount: Checksum for group %u failed (%u!=%u)",
4738 		g, le16_to_cpu(ext4_group_desc_csum(sb, g, gdp)),
4739 					       le16_to_cpu(gdp->bg_checksum));
4740 					err = -EFSBADCRC;
4741 					goto restore_opts;
4742 				}
4743 			}
4744 
4745 			/*
4746 			 * If we have an unprocessed orphan list hanging
4747 			 * around from a previously readonly bdev mount,
4748 			 * require a full umount/remount for now.
4749 			 */
4750 			if (es->s_last_orphan) {
4751 				ext4_msg(sb, KERN_WARNING, "Couldn't "
4752 				       "remount RDWR because of unprocessed "
4753 				       "orphan inode list.  Please "
4754 				       "umount/remount instead");
4755 				err = -EINVAL;
4756 				goto restore_opts;
4757 			}
4758 
4759 			/*
4760 			 * Mounting a RDONLY partition read-write, so reread
4761 			 * and store the current valid flag.  (It may have
4762 			 * been changed by e2fsck since we originally mounted
4763 			 * the partition.)
4764 			 */
4765 			if (sbi->s_journal)
4766 				ext4_clear_journal_err(sb, es);
4767 			sbi->s_mount_state = le16_to_cpu(es->s_state);
4768 			if (!ext4_setup_super(sb, es, 0))
4769 				sb->s_flags &= ~MS_RDONLY;
4770 			if (ext4_has_feature_mmp(sb))
4771 				if (ext4_multi_mount_protect(sb,
4772 						le64_to_cpu(es->s_mmp_block))) {
4773 					err = -EROFS;
4774 					goto restore_opts;
4775 				}
4776 			enable_quota = 1;
4777 		}
4778 	}
4779 
4780 	/*
4781 	 * Reinitialize lazy itable initialization thread based on
4782 	 * current settings
4783 	 */
4784 	if ((sb->s_flags & MS_RDONLY) || !test_opt(sb, INIT_INODE_TABLE))
4785 		ext4_unregister_li_request(sb);
4786 	else {
4787 		ext4_group_t first_not_zeroed;
4788 		first_not_zeroed = ext4_has_uninit_itable(sb);
4789 		ext4_register_li_request(sb, first_not_zeroed);
4790 	}
4791 
4792 	ext4_setup_system_zone(sb);
4793 	if (sbi->s_journal == NULL && !(old_sb_flags & MS_RDONLY))
4794 		ext4_commit_super(sb, 1);
4795 
4796 #ifdef CONFIG_QUOTA
4797 	/* Release old quota file names */
4798 	for (i = 0; i < EXT4_MAXQUOTAS; i++)
4799 		kfree(old_opts.s_qf_names[i]);
4800 	if (enable_quota) {
4801 		if (sb_any_quota_suspended(sb))
4802 			dquot_resume(sb, -1);
4803 		else if (ext4_has_feature_quota(sb)) {
4804 			err = ext4_enable_quotas(sb);
4805 			if (err)
4806 				goto restore_opts;
4807 		}
4808 	}
4809 #endif
4810 
4811 	*flags = (*flags & ~MS_LAZYTIME) | (sb->s_flags & MS_LAZYTIME);
4812 	ext4_msg(sb, KERN_INFO, "re-mounted. Opts: %s", orig_data);
4813 	kfree(orig_data);
4814 	return 0;
4815 
4816 restore_opts:
4817 	sb->s_flags = old_sb_flags;
4818 	sbi->s_mount_opt = old_opts.s_mount_opt;
4819 	sbi->s_mount_opt2 = old_opts.s_mount_opt2;
4820 	sbi->s_resuid = old_opts.s_resuid;
4821 	sbi->s_resgid = old_opts.s_resgid;
4822 	sbi->s_commit_interval = old_opts.s_commit_interval;
4823 	sbi->s_min_batch_time = old_opts.s_min_batch_time;
4824 	sbi->s_max_batch_time = old_opts.s_max_batch_time;
4825 #ifdef CONFIG_QUOTA
4826 	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
4827 	for (i = 0; i < EXT4_MAXQUOTAS; i++) {
4828 		kfree(sbi->s_qf_names[i]);
4829 		sbi->s_qf_names[i] = old_opts.s_qf_names[i];
4830 	}
4831 #endif
4832 	kfree(orig_data);
4833 	return err;
4834 }
4835 
4836 #ifdef CONFIG_QUOTA
4837 static int ext4_statfs_project(struct super_block *sb,
4838 			       kprojid_t projid, struct kstatfs *buf)
4839 {
4840 	struct kqid qid;
4841 	struct dquot *dquot;
4842 	u64 limit;
4843 	u64 curblock;
4844 
4845 	qid = make_kqid_projid(projid);
4846 	dquot = dqget(sb, qid);
4847 	if (IS_ERR(dquot))
4848 		return PTR_ERR(dquot);
4849 	spin_lock(&dq_data_lock);
4850 
4851 	limit = (dquot->dq_dqb.dqb_bsoftlimit ?
4852 		 dquot->dq_dqb.dqb_bsoftlimit :
4853 		 dquot->dq_dqb.dqb_bhardlimit) >> sb->s_blocksize_bits;
4854 	if (limit && buf->f_blocks > limit) {
4855 		curblock = dquot->dq_dqb.dqb_curspace >> sb->s_blocksize_bits;
4856 		buf->f_blocks = limit;
4857 		buf->f_bfree = buf->f_bavail =
4858 			(buf->f_blocks > curblock) ?
4859 			 (buf->f_blocks - curblock) : 0;
4860 	}
4861 
4862 	limit = dquot->dq_dqb.dqb_isoftlimit ?
4863 		dquot->dq_dqb.dqb_isoftlimit :
4864 		dquot->dq_dqb.dqb_ihardlimit;
4865 	if (limit && buf->f_files > limit) {
4866 		buf->f_files = limit;
4867 		buf->f_ffree =
4868 			(buf->f_files > dquot->dq_dqb.dqb_curinodes) ?
4869 			 (buf->f_files - dquot->dq_dqb.dqb_curinodes) : 0;
4870 	}
4871 
4872 	spin_unlock(&dq_data_lock);
4873 	dqput(dquot);
4874 	return 0;
4875 }
4876 #endif
4877 
4878 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
4879 {
4880 	struct super_block *sb = dentry->d_sb;
4881 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4882 	struct ext4_super_block *es = sbi->s_es;
4883 	ext4_fsblk_t overhead = 0, resv_blocks;
4884 	u64 fsid;
4885 	s64 bfree;
4886 	resv_blocks = EXT4_C2B(sbi, atomic64_read(&sbi->s_resv_clusters));
4887 
4888 	if (!test_opt(sb, MINIX_DF))
4889 		overhead = sbi->s_overhead;
4890 
4891 	buf->f_type = EXT4_SUPER_MAGIC;
4892 	buf->f_bsize = sb->s_blocksize;
4893 	buf->f_blocks = ext4_blocks_count(es) - EXT4_C2B(sbi, overhead);
4894 	bfree = percpu_counter_sum_positive(&sbi->s_freeclusters_counter) -
4895 		percpu_counter_sum_positive(&sbi->s_dirtyclusters_counter);
4896 	/* prevent underflow in case that few free space is available */
4897 	buf->f_bfree = EXT4_C2B(sbi, max_t(s64, bfree, 0));
4898 	buf->f_bavail = buf->f_bfree -
4899 			(ext4_r_blocks_count(es) + resv_blocks);
4900 	if (buf->f_bfree < (ext4_r_blocks_count(es) + resv_blocks))
4901 		buf->f_bavail = 0;
4902 	buf->f_files = le32_to_cpu(es->s_inodes_count);
4903 	buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter);
4904 	buf->f_namelen = EXT4_NAME_LEN;
4905 	fsid = le64_to_cpup((void *)es->s_uuid) ^
4906 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
4907 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
4908 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
4909 
4910 #ifdef CONFIG_QUOTA
4911 	if (ext4_test_inode_flag(dentry->d_inode, EXT4_INODE_PROJINHERIT) &&
4912 	    sb_has_quota_limits_enabled(sb, PRJQUOTA))
4913 		ext4_statfs_project(sb, EXT4_I(dentry->d_inode)->i_projid, buf);
4914 #endif
4915 	return 0;
4916 }
4917 
4918 /* Helper function for writing quotas on sync - we need to start transaction
4919  * before quota file is locked for write. Otherwise the are possible deadlocks:
4920  * Process 1                         Process 2
4921  * ext4_create()                     quota_sync()
4922  *   jbd2_journal_start()                  write_dquot()
4923  *   dquot_initialize()                         down(dqio_mutex)
4924  *     down(dqio_mutex)                    jbd2_journal_start()
4925  *
4926  */
4927 
4928 #ifdef CONFIG_QUOTA
4929 
4930 static inline struct inode *dquot_to_inode(struct dquot *dquot)
4931 {
4932 	return sb_dqopt(dquot->dq_sb)->files[dquot->dq_id.type];
4933 }
4934 
4935 static int ext4_write_dquot(struct dquot *dquot)
4936 {
4937 	int ret, err;
4938 	handle_t *handle;
4939 	struct inode *inode;
4940 
4941 	inode = dquot_to_inode(dquot);
4942 	handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
4943 				    EXT4_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
4944 	if (IS_ERR(handle))
4945 		return PTR_ERR(handle);
4946 	ret = dquot_commit(dquot);
4947 	err = ext4_journal_stop(handle);
4948 	if (!ret)
4949 		ret = err;
4950 	return ret;
4951 }
4952 
4953 static int ext4_acquire_dquot(struct dquot *dquot)
4954 {
4955 	int ret, err;
4956 	handle_t *handle;
4957 
4958 	handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
4959 				    EXT4_QUOTA_INIT_BLOCKS(dquot->dq_sb));
4960 	if (IS_ERR(handle))
4961 		return PTR_ERR(handle);
4962 	ret = dquot_acquire(dquot);
4963 	err = ext4_journal_stop(handle);
4964 	if (!ret)
4965 		ret = err;
4966 	return ret;
4967 }
4968 
4969 static int ext4_release_dquot(struct dquot *dquot)
4970 {
4971 	int ret, err;
4972 	handle_t *handle;
4973 
4974 	handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
4975 				    EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
4976 	if (IS_ERR(handle)) {
4977 		/* Release dquot anyway to avoid endless cycle in dqput() */
4978 		dquot_release(dquot);
4979 		return PTR_ERR(handle);
4980 	}
4981 	ret = dquot_release(dquot);
4982 	err = ext4_journal_stop(handle);
4983 	if (!ret)
4984 		ret = err;
4985 	return ret;
4986 }
4987 
4988 static int ext4_mark_dquot_dirty(struct dquot *dquot)
4989 {
4990 	struct super_block *sb = dquot->dq_sb;
4991 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4992 
4993 	/* Are we journaling quotas? */
4994 	if (ext4_has_feature_quota(sb) ||
4995 	    sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
4996 		dquot_mark_dquot_dirty(dquot);
4997 		return ext4_write_dquot(dquot);
4998 	} else {
4999 		return dquot_mark_dquot_dirty(dquot);
5000 	}
5001 }
5002 
5003 static int ext4_write_info(struct super_block *sb, int type)
5004 {
5005 	int ret, err;
5006 	handle_t *handle;
5007 
5008 	/* Data block + inode block */
5009 	handle = ext4_journal_start(d_inode(sb->s_root), EXT4_HT_QUOTA, 2);
5010 	if (IS_ERR(handle))
5011 		return PTR_ERR(handle);
5012 	ret = dquot_commit_info(sb, type);
5013 	err = ext4_journal_stop(handle);
5014 	if (!ret)
5015 		ret = err;
5016 	return ret;
5017 }
5018 
5019 /*
5020  * Turn on quotas during mount time - we need to find
5021  * the quota file and such...
5022  */
5023 static int ext4_quota_on_mount(struct super_block *sb, int type)
5024 {
5025 	return dquot_quota_on_mount(sb, EXT4_SB(sb)->s_qf_names[type],
5026 					EXT4_SB(sb)->s_jquota_fmt, type);
5027 }
5028 
5029 /*
5030  * Standard function to be called on quota_on
5031  */
5032 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
5033 			 struct path *path)
5034 {
5035 	int err;
5036 
5037 	if (!test_opt(sb, QUOTA))
5038 		return -EINVAL;
5039 
5040 	/* Quotafile not on the same filesystem? */
5041 	if (path->dentry->d_sb != sb)
5042 		return -EXDEV;
5043 	/* Journaling quota? */
5044 	if (EXT4_SB(sb)->s_qf_names[type]) {
5045 		/* Quotafile not in fs root? */
5046 		if (path->dentry->d_parent != sb->s_root)
5047 			ext4_msg(sb, KERN_WARNING,
5048 				"Quota file not on filesystem root. "
5049 				"Journaled quota will not work");
5050 	}
5051 
5052 	/*
5053 	 * When we journal data on quota file, we have to flush journal to see
5054 	 * all updates to the file when we bypass pagecache...
5055 	 */
5056 	if (EXT4_SB(sb)->s_journal &&
5057 	    ext4_should_journal_data(d_inode(path->dentry))) {
5058 		/*
5059 		 * We don't need to lock updates but journal_flush() could
5060 		 * otherwise be livelocked...
5061 		 */
5062 		jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
5063 		err = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
5064 		jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
5065 		if (err)
5066 			return err;
5067 	}
5068 
5069 	return dquot_quota_on(sb, type, format_id, path);
5070 }
5071 
5072 static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
5073 			     unsigned int flags)
5074 {
5075 	int err;
5076 	struct inode *qf_inode;
5077 	unsigned long qf_inums[EXT4_MAXQUOTAS] = {
5078 		le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
5079 		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum),
5080 		le32_to_cpu(EXT4_SB(sb)->s_es->s_prj_quota_inum)
5081 	};
5082 
5083 	BUG_ON(!ext4_has_feature_quota(sb));
5084 
5085 	if (!qf_inums[type])
5086 		return -EPERM;
5087 
5088 	qf_inode = ext4_iget(sb, qf_inums[type]);
5089 	if (IS_ERR(qf_inode)) {
5090 		ext4_error(sb, "Bad quota inode # %lu", qf_inums[type]);
5091 		return PTR_ERR(qf_inode);
5092 	}
5093 
5094 	/* Don't account quota for quota files to avoid recursion */
5095 	qf_inode->i_flags |= S_NOQUOTA;
5096 	err = dquot_enable(qf_inode, type, format_id, flags);
5097 	iput(qf_inode);
5098 
5099 	return err;
5100 }
5101 
5102 /* Enable usage tracking for all quota types. */
5103 static int ext4_enable_quotas(struct super_block *sb)
5104 {
5105 	int type, err = 0;
5106 	unsigned long qf_inums[EXT4_MAXQUOTAS] = {
5107 		le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
5108 		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum),
5109 		le32_to_cpu(EXT4_SB(sb)->s_es->s_prj_quota_inum)
5110 	};
5111 
5112 	sb_dqopt(sb)->flags |= DQUOT_QUOTA_SYS_FILE;
5113 	for (type = 0; type < EXT4_MAXQUOTAS; type++) {
5114 		if (qf_inums[type]) {
5115 			err = ext4_quota_enable(sb, type, QFMT_VFS_V1,
5116 						DQUOT_USAGE_ENABLED);
5117 			if (err) {
5118 				ext4_warning(sb,
5119 					"Failed to enable quota tracking "
5120 					"(type=%d, err=%d). Please run "
5121 					"e2fsck to fix.", type, err);
5122 				return err;
5123 			}
5124 		}
5125 	}
5126 	return 0;
5127 }
5128 
5129 static int ext4_quota_off(struct super_block *sb, int type)
5130 {
5131 	struct inode *inode = sb_dqopt(sb)->files[type];
5132 	handle_t *handle;
5133 
5134 	/* Force all delayed allocation blocks to be allocated.
5135 	 * Caller already holds s_umount sem */
5136 	if (test_opt(sb, DELALLOC))
5137 		sync_filesystem(sb);
5138 
5139 	if (!inode)
5140 		goto out;
5141 
5142 	/* Update modification times of quota files when userspace can
5143 	 * start looking at them */
5144 	handle = ext4_journal_start(inode, EXT4_HT_QUOTA, 1);
5145 	if (IS_ERR(handle))
5146 		goto out;
5147 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
5148 	ext4_mark_inode_dirty(handle, inode);
5149 	ext4_journal_stop(handle);
5150 
5151 out:
5152 	return dquot_quota_off(sb, type);
5153 }
5154 
5155 /* Read data from quotafile - avoid pagecache and such because we cannot afford
5156  * acquiring the locks... As quota files are never truncated and quota code
5157  * itself serializes the operations (and no one else should touch the files)
5158  * we don't have to be afraid of races */
5159 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
5160 			       size_t len, loff_t off)
5161 {
5162 	struct inode *inode = sb_dqopt(sb)->files[type];
5163 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
5164 	int offset = off & (sb->s_blocksize - 1);
5165 	int tocopy;
5166 	size_t toread;
5167 	struct buffer_head *bh;
5168 	loff_t i_size = i_size_read(inode);
5169 
5170 	if (off > i_size)
5171 		return 0;
5172 	if (off+len > i_size)
5173 		len = i_size-off;
5174 	toread = len;
5175 	while (toread > 0) {
5176 		tocopy = sb->s_blocksize - offset < toread ?
5177 				sb->s_blocksize - offset : toread;
5178 		bh = ext4_bread(NULL, inode, blk, 0);
5179 		if (IS_ERR(bh))
5180 			return PTR_ERR(bh);
5181 		if (!bh)	/* A hole? */
5182 			memset(data, 0, tocopy);
5183 		else
5184 			memcpy(data, bh->b_data+offset, tocopy);
5185 		brelse(bh);
5186 		offset = 0;
5187 		toread -= tocopy;
5188 		data += tocopy;
5189 		blk++;
5190 	}
5191 	return len;
5192 }
5193 
5194 /* Write to quotafile (we know the transaction is already started and has
5195  * enough credits) */
5196 static ssize_t ext4_quota_write(struct super_block *sb, int type,
5197 				const char *data, size_t len, loff_t off)
5198 {
5199 	struct inode *inode = sb_dqopt(sb)->files[type];
5200 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
5201 	int err, offset = off & (sb->s_blocksize - 1);
5202 	int retries = 0;
5203 	struct buffer_head *bh;
5204 	handle_t *handle = journal_current_handle();
5205 
5206 	if (EXT4_SB(sb)->s_journal && !handle) {
5207 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
5208 			" cancelled because transaction is not started",
5209 			(unsigned long long)off, (unsigned long long)len);
5210 		return -EIO;
5211 	}
5212 	/*
5213 	 * Since we account only one data block in transaction credits,
5214 	 * then it is impossible to cross a block boundary.
5215 	 */
5216 	if (sb->s_blocksize - offset < len) {
5217 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
5218 			" cancelled because not block aligned",
5219 			(unsigned long long)off, (unsigned long long)len);
5220 		return -EIO;
5221 	}
5222 
5223 	do {
5224 		bh = ext4_bread(handle, inode, blk,
5225 				EXT4_GET_BLOCKS_CREATE |
5226 				EXT4_GET_BLOCKS_METADATA_NOFAIL);
5227 	} while (IS_ERR(bh) && (PTR_ERR(bh) == -ENOSPC) &&
5228 		 ext4_should_retry_alloc(inode->i_sb, &retries));
5229 	if (IS_ERR(bh))
5230 		return PTR_ERR(bh);
5231 	if (!bh)
5232 		goto out;
5233 	BUFFER_TRACE(bh, "get write access");
5234 	err = ext4_journal_get_write_access(handle, bh);
5235 	if (err) {
5236 		brelse(bh);
5237 		return err;
5238 	}
5239 	lock_buffer(bh);
5240 	memcpy(bh->b_data+offset, data, len);
5241 	flush_dcache_page(bh->b_page);
5242 	unlock_buffer(bh);
5243 	err = ext4_handle_dirty_metadata(handle, NULL, bh);
5244 	brelse(bh);
5245 out:
5246 	if (inode->i_size < off + len) {
5247 		i_size_write(inode, off + len);
5248 		EXT4_I(inode)->i_disksize = inode->i_size;
5249 		ext4_mark_inode_dirty(handle, inode);
5250 	}
5251 	return len;
5252 }
5253 
5254 #endif
5255 
5256 static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
5257 		       const char *dev_name, void *data)
5258 {
5259 	return mount_bdev(fs_type, flags, dev_name, data, ext4_fill_super);
5260 }
5261 
5262 #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT2)
5263 static inline void register_as_ext2(void)
5264 {
5265 	int err = register_filesystem(&ext2_fs_type);
5266 	if (err)
5267 		printk(KERN_WARNING
5268 		       "EXT4-fs: Unable to register as ext2 (%d)\n", err);
5269 }
5270 
5271 static inline void unregister_as_ext2(void)
5272 {
5273 	unregister_filesystem(&ext2_fs_type);
5274 }
5275 
5276 static inline int ext2_feature_set_ok(struct super_block *sb)
5277 {
5278 	if (ext4_has_unknown_ext2_incompat_features(sb))
5279 		return 0;
5280 	if (sb->s_flags & MS_RDONLY)
5281 		return 1;
5282 	if (ext4_has_unknown_ext2_ro_compat_features(sb))
5283 		return 0;
5284 	return 1;
5285 }
5286 #else
5287 static inline void register_as_ext2(void) { }
5288 static inline void unregister_as_ext2(void) { }
5289 static inline int ext2_feature_set_ok(struct super_block *sb) { return 0; }
5290 #endif
5291 
5292 static inline void register_as_ext3(void)
5293 {
5294 	int err = register_filesystem(&ext3_fs_type);
5295 	if (err)
5296 		printk(KERN_WARNING
5297 		       "EXT4-fs: Unable to register as ext3 (%d)\n", err);
5298 }
5299 
5300 static inline void unregister_as_ext3(void)
5301 {
5302 	unregister_filesystem(&ext3_fs_type);
5303 }
5304 
5305 static inline int ext3_feature_set_ok(struct super_block *sb)
5306 {
5307 	if (ext4_has_unknown_ext3_incompat_features(sb))
5308 		return 0;
5309 	if (!ext4_has_feature_journal(sb))
5310 		return 0;
5311 	if (sb->s_flags & MS_RDONLY)
5312 		return 1;
5313 	if (ext4_has_unknown_ext3_ro_compat_features(sb))
5314 		return 0;
5315 	return 1;
5316 }
5317 
5318 static struct file_system_type ext4_fs_type = {
5319 	.owner		= THIS_MODULE,
5320 	.name		= "ext4",
5321 	.mount		= ext4_mount,
5322 	.kill_sb	= kill_block_super,
5323 	.fs_flags	= FS_REQUIRES_DEV,
5324 };
5325 MODULE_ALIAS_FS("ext4");
5326 
5327 /* Shared across all ext4 file systems */
5328 wait_queue_head_t ext4__ioend_wq[EXT4_WQ_HASH_SZ];
5329 
5330 static int __init ext4_init_fs(void)
5331 {
5332 	int i, err;
5333 
5334 	ratelimit_state_init(&ext4_mount_msg_ratelimit, 30 * HZ, 64);
5335 	ext4_li_info = NULL;
5336 	mutex_init(&ext4_li_mtx);
5337 
5338 	/* Build-time check for flags consistency */
5339 	ext4_check_flag_values();
5340 
5341 	for (i = 0; i < EXT4_WQ_HASH_SZ; i++)
5342 		init_waitqueue_head(&ext4__ioend_wq[i]);
5343 
5344 	err = ext4_init_es();
5345 	if (err)
5346 		return err;
5347 
5348 	err = ext4_init_pageio();
5349 	if (err)
5350 		goto out5;
5351 
5352 	err = ext4_init_system_zone();
5353 	if (err)
5354 		goto out4;
5355 
5356 	err = ext4_init_sysfs();
5357 	if (err)
5358 		goto out3;
5359 
5360 	err = ext4_init_mballoc();
5361 	if (err)
5362 		goto out2;
5363 	err = init_inodecache();
5364 	if (err)
5365 		goto out1;
5366 	register_as_ext3();
5367 	register_as_ext2();
5368 	err = register_filesystem(&ext4_fs_type);
5369 	if (err)
5370 		goto out;
5371 
5372 	return 0;
5373 out:
5374 	unregister_as_ext2();
5375 	unregister_as_ext3();
5376 	destroy_inodecache();
5377 out1:
5378 	ext4_exit_mballoc();
5379 out2:
5380 	ext4_exit_sysfs();
5381 out3:
5382 	ext4_exit_system_zone();
5383 out4:
5384 	ext4_exit_pageio();
5385 out5:
5386 	ext4_exit_es();
5387 
5388 	return err;
5389 }
5390 
5391 static void __exit ext4_exit_fs(void)
5392 {
5393 	ext4_exit_crypto();
5394 	ext4_destroy_lazyinit_thread();
5395 	unregister_as_ext2();
5396 	unregister_as_ext3();
5397 	unregister_filesystem(&ext4_fs_type);
5398 	destroy_inodecache();
5399 	ext4_exit_mballoc();
5400 	ext4_exit_sysfs();
5401 	ext4_exit_system_zone();
5402 	ext4_exit_pageio();
5403 	ext4_exit_es();
5404 }
5405 
5406 MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
5407 MODULE_DESCRIPTION("Fourth Extended Filesystem");
5408 MODULE_LICENSE("GPL");
5409 module_init(ext4_init_fs)
5410 module_exit(ext4_exit_fs)
5411