xref: /openbmc/linux/fs/ext4/super.c (revision 5bb7889f)
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/jbd2.h>
25 #include <linux/slab.h>
26 #include <linux/init.h>
27 #include <linux/blkdev.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/proc_fs.h>
38 #include <linux/ctype.h>
39 #include <linux/log2.h>
40 #include <linux/crc16.h>
41 #include <linux/cleancache.h>
42 #include <asm/uaccess.h>
43 
44 #include <linux/kthread.h>
45 #include <linux/freezer.h>
46 
47 #include "ext4.h"
48 #include "ext4_extents.h"	/* Needed for trace points definition */
49 #include "ext4_jbd2.h"
50 #include "xattr.h"
51 #include "acl.h"
52 #include "mballoc.h"
53 
54 #define CREATE_TRACE_POINTS
55 #include <trace/events/ext4.h>
56 
57 static struct proc_dir_entry *ext4_proc_root;
58 static struct kset *ext4_kset;
59 static struct ext4_lazy_init *ext4_li_info;
60 static struct mutex ext4_li_mtx;
61 static struct ext4_features *ext4_feat;
62 static int ext4_mballoc_ready;
63 
64 static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
65 			     unsigned long journal_devnum);
66 static int ext4_show_options(struct seq_file *seq, struct dentry *root);
67 static int ext4_commit_super(struct super_block *sb, int sync);
68 static void ext4_mark_recovery_complete(struct super_block *sb,
69 					struct ext4_super_block *es);
70 static void ext4_clear_journal_err(struct super_block *sb,
71 				   struct ext4_super_block *es);
72 static int ext4_sync_fs(struct super_block *sb, int wait);
73 static int ext4_sync_fs_nojournal(struct super_block *sb, int wait);
74 static int ext4_remount(struct super_block *sb, int *flags, char *data);
75 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf);
76 static int ext4_unfreeze(struct super_block *sb);
77 static int ext4_freeze(struct super_block *sb);
78 static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
79 		       const char *dev_name, void *data);
80 static inline int ext2_feature_set_ok(struct super_block *sb);
81 static inline int ext3_feature_set_ok(struct super_block *sb);
82 static int ext4_feature_set_ok(struct super_block *sb, int readonly);
83 static void ext4_destroy_lazyinit_thread(void);
84 static void ext4_unregister_li_request(struct super_block *sb);
85 static void ext4_clear_request_list(void);
86 static int ext4_reserve_clusters(struct ext4_sb_info *, ext4_fsblk_t);
87 
88 #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
89 static struct file_system_type ext2_fs_type = {
90 	.owner		= THIS_MODULE,
91 	.name		= "ext2",
92 	.mount		= ext4_mount,
93 	.kill_sb	= kill_block_super,
94 	.fs_flags	= FS_REQUIRES_DEV,
95 };
96 MODULE_ALIAS_FS("ext2");
97 MODULE_ALIAS("ext2");
98 #define IS_EXT2_SB(sb) ((sb)->s_bdev->bd_holder == &ext2_fs_type)
99 #else
100 #define IS_EXT2_SB(sb) (0)
101 #endif
102 
103 
104 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
105 static struct file_system_type ext3_fs_type = {
106 	.owner		= THIS_MODULE,
107 	.name		= "ext3",
108 	.mount		= ext4_mount,
109 	.kill_sb	= kill_block_super,
110 	.fs_flags	= FS_REQUIRES_DEV,
111 };
112 MODULE_ALIAS_FS("ext3");
113 MODULE_ALIAS("ext3");
114 #define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type)
115 #else
116 #define IS_EXT3_SB(sb) (0)
117 #endif
118 
119 static int ext4_verify_csum_type(struct super_block *sb,
120 				 struct ext4_super_block *es)
121 {
122 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
123 					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
124 		return 1;
125 
126 	return es->s_checksum_type == EXT4_CRC32C_CHKSUM;
127 }
128 
129 static __le32 ext4_superblock_csum(struct super_block *sb,
130 				   struct ext4_super_block *es)
131 {
132 	struct ext4_sb_info *sbi = EXT4_SB(sb);
133 	int offset = offsetof(struct ext4_super_block, s_checksum);
134 	__u32 csum;
135 
136 	csum = ext4_chksum(sbi, ~0, (char *)es, offset);
137 
138 	return cpu_to_le32(csum);
139 }
140 
141 static int ext4_superblock_csum_verify(struct super_block *sb,
142 				       struct ext4_super_block *es)
143 {
144 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
145 				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
146 		return 1;
147 
148 	return es->s_checksum == ext4_superblock_csum(sb, es);
149 }
150 
151 void ext4_superblock_csum_set(struct super_block *sb)
152 {
153 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
154 
155 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
156 		EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
157 		return;
158 
159 	es->s_checksum = ext4_superblock_csum(sb, es);
160 }
161 
162 void *ext4_kvmalloc(size_t size, gfp_t flags)
163 {
164 	void *ret;
165 
166 	ret = kmalloc(size, flags | __GFP_NOWARN);
167 	if (!ret)
168 		ret = __vmalloc(size, flags, PAGE_KERNEL);
169 	return ret;
170 }
171 
172 void *ext4_kvzalloc(size_t size, gfp_t flags)
173 {
174 	void *ret;
175 
176 	ret = kzalloc(size, flags | __GFP_NOWARN);
177 	if (!ret)
178 		ret = __vmalloc(size, flags | __GFP_ZERO, PAGE_KERNEL);
179 	return ret;
180 }
181 
182 void ext4_kvfree(void *ptr)
183 {
184 	if (is_vmalloc_addr(ptr))
185 		vfree(ptr);
186 	else
187 		kfree(ptr);
188 
189 }
190 
191 ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
192 			       struct ext4_group_desc *bg)
193 {
194 	return le32_to_cpu(bg->bg_block_bitmap_lo) |
195 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
196 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_block_bitmap_hi) << 32 : 0);
197 }
198 
199 ext4_fsblk_t ext4_inode_bitmap(struct super_block *sb,
200 			       struct ext4_group_desc *bg)
201 {
202 	return le32_to_cpu(bg->bg_inode_bitmap_lo) |
203 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
204 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_bitmap_hi) << 32 : 0);
205 }
206 
207 ext4_fsblk_t ext4_inode_table(struct super_block *sb,
208 			      struct ext4_group_desc *bg)
209 {
210 	return le32_to_cpu(bg->bg_inode_table_lo) |
211 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
212 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_table_hi) << 32 : 0);
213 }
214 
215 __u32 ext4_free_group_clusters(struct super_block *sb,
216 			       struct ext4_group_desc *bg)
217 {
218 	return le16_to_cpu(bg->bg_free_blocks_count_lo) |
219 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
220 		 (__u32)le16_to_cpu(bg->bg_free_blocks_count_hi) << 16 : 0);
221 }
222 
223 __u32 ext4_free_inodes_count(struct super_block *sb,
224 			      struct ext4_group_desc *bg)
225 {
226 	return le16_to_cpu(bg->bg_free_inodes_count_lo) |
227 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
228 		 (__u32)le16_to_cpu(bg->bg_free_inodes_count_hi) << 16 : 0);
229 }
230 
231 __u32 ext4_used_dirs_count(struct super_block *sb,
232 			      struct ext4_group_desc *bg)
233 {
234 	return le16_to_cpu(bg->bg_used_dirs_count_lo) |
235 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
236 		 (__u32)le16_to_cpu(bg->bg_used_dirs_count_hi) << 16 : 0);
237 }
238 
239 __u32 ext4_itable_unused_count(struct super_block *sb,
240 			      struct ext4_group_desc *bg)
241 {
242 	return le16_to_cpu(bg->bg_itable_unused_lo) |
243 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
244 		 (__u32)le16_to_cpu(bg->bg_itable_unused_hi) << 16 : 0);
245 }
246 
247 void ext4_block_bitmap_set(struct super_block *sb,
248 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
249 {
250 	bg->bg_block_bitmap_lo = cpu_to_le32((u32)blk);
251 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
252 		bg->bg_block_bitmap_hi = cpu_to_le32(blk >> 32);
253 }
254 
255 void ext4_inode_bitmap_set(struct super_block *sb,
256 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
257 {
258 	bg->bg_inode_bitmap_lo  = cpu_to_le32((u32)blk);
259 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
260 		bg->bg_inode_bitmap_hi = cpu_to_le32(blk >> 32);
261 }
262 
263 void ext4_inode_table_set(struct super_block *sb,
264 			  struct ext4_group_desc *bg, ext4_fsblk_t blk)
265 {
266 	bg->bg_inode_table_lo = cpu_to_le32((u32)blk);
267 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
268 		bg->bg_inode_table_hi = cpu_to_le32(blk >> 32);
269 }
270 
271 void ext4_free_group_clusters_set(struct super_block *sb,
272 				  struct ext4_group_desc *bg, __u32 count)
273 {
274 	bg->bg_free_blocks_count_lo = cpu_to_le16((__u16)count);
275 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
276 		bg->bg_free_blocks_count_hi = cpu_to_le16(count >> 16);
277 }
278 
279 void ext4_free_inodes_set(struct super_block *sb,
280 			  struct ext4_group_desc *bg, __u32 count)
281 {
282 	bg->bg_free_inodes_count_lo = cpu_to_le16((__u16)count);
283 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
284 		bg->bg_free_inodes_count_hi = cpu_to_le16(count >> 16);
285 }
286 
287 void ext4_used_dirs_set(struct super_block *sb,
288 			  struct ext4_group_desc *bg, __u32 count)
289 {
290 	bg->bg_used_dirs_count_lo = cpu_to_le16((__u16)count);
291 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
292 		bg->bg_used_dirs_count_hi = cpu_to_le16(count >> 16);
293 }
294 
295 void ext4_itable_unused_set(struct super_block *sb,
296 			  struct ext4_group_desc *bg, __u32 count)
297 {
298 	bg->bg_itable_unused_lo = cpu_to_le16((__u16)count);
299 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
300 		bg->bg_itable_unused_hi = cpu_to_le16(count >> 16);
301 }
302 
303 
304 static void __save_error_info(struct super_block *sb, const char *func,
305 			    unsigned int line)
306 {
307 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
308 
309 	EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
310 	es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
311 	es->s_last_error_time = cpu_to_le32(get_seconds());
312 	strncpy(es->s_last_error_func, func, sizeof(es->s_last_error_func));
313 	es->s_last_error_line = cpu_to_le32(line);
314 	if (!es->s_first_error_time) {
315 		es->s_first_error_time = es->s_last_error_time;
316 		strncpy(es->s_first_error_func, func,
317 			sizeof(es->s_first_error_func));
318 		es->s_first_error_line = cpu_to_le32(line);
319 		es->s_first_error_ino = es->s_last_error_ino;
320 		es->s_first_error_block = es->s_last_error_block;
321 	}
322 	/*
323 	 * Start the daily error reporting function if it hasn't been
324 	 * started already
325 	 */
326 	if (!es->s_error_count)
327 		mod_timer(&EXT4_SB(sb)->s_err_report, jiffies + 24*60*60*HZ);
328 	le32_add_cpu(&es->s_error_count, 1);
329 }
330 
331 static void save_error_info(struct super_block *sb, const char *func,
332 			    unsigned int line)
333 {
334 	__save_error_info(sb, func, line);
335 	ext4_commit_super(sb, 1);
336 }
337 
338 /*
339  * The del_gendisk() function uninitializes the disk-specific data
340  * structures, including the bdi structure, without telling anyone
341  * else.  Once this happens, any attempt to call mark_buffer_dirty()
342  * (for example, by ext4_commit_super), will cause a kernel OOPS.
343  * This is a kludge to prevent these oops until we can put in a proper
344  * hook in del_gendisk() to inform the VFS and file system layers.
345  */
346 static int block_device_ejected(struct super_block *sb)
347 {
348 	struct inode *bd_inode = sb->s_bdev->bd_inode;
349 	struct backing_dev_info *bdi = bd_inode->i_mapping->backing_dev_info;
350 
351 	return bdi->dev == NULL;
352 }
353 
354 static void ext4_journal_commit_callback(journal_t *journal, transaction_t *txn)
355 {
356 	struct super_block		*sb = journal->j_private;
357 	struct ext4_sb_info		*sbi = EXT4_SB(sb);
358 	int				error = is_journal_aborted(journal);
359 	struct ext4_journal_cb_entry	*jce;
360 
361 	BUG_ON(txn->t_state == T_FINISHED);
362 	spin_lock(&sbi->s_md_lock);
363 	while (!list_empty(&txn->t_private_list)) {
364 		jce = list_entry(txn->t_private_list.next,
365 				 struct ext4_journal_cb_entry, jce_list);
366 		list_del_init(&jce->jce_list);
367 		spin_unlock(&sbi->s_md_lock);
368 		jce->jce_func(sb, jce, error);
369 		spin_lock(&sbi->s_md_lock);
370 	}
371 	spin_unlock(&sbi->s_md_lock);
372 }
373 
374 /* Deal with the reporting of failure conditions on a filesystem such as
375  * inconsistencies detected or read IO failures.
376  *
377  * On ext2, we can store the error state of the filesystem in the
378  * superblock.  That is not possible on ext4, because we may have other
379  * write ordering constraints on the superblock which prevent us from
380  * writing it out straight away; and given that the journal is about to
381  * be aborted, we can't rely on the current, or future, transactions to
382  * write out the superblock safely.
383  *
384  * We'll just use the jbd2_journal_abort() error code to record an error in
385  * the journal instead.  On recovery, the journal will complain about
386  * that error until we've noted it down and cleared it.
387  */
388 
389 static void ext4_handle_error(struct super_block *sb)
390 {
391 	if (sb->s_flags & MS_RDONLY)
392 		return;
393 
394 	if (!test_opt(sb, ERRORS_CONT)) {
395 		journal_t *journal = EXT4_SB(sb)->s_journal;
396 
397 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
398 		if (journal)
399 			jbd2_journal_abort(journal, -EIO);
400 	}
401 	if (test_opt(sb, ERRORS_RO)) {
402 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
403 		/*
404 		 * Make sure updated value of ->s_mount_flags will be visible
405 		 * before ->s_flags update
406 		 */
407 		smp_wmb();
408 		sb->s_flags |= MS_RDONLY;
409 	}
410 	if (test_opt(sb, ERRORS_PANIC))
411 		panic("EXT4-fs (device %s): panic forced after error\n",
412 			sb->s_id);
413 }
414 
415 #define ext4_error_ratelimit(sb)					\
416 		___ratelimit(&(EXT4_SB(sb)->s_err_ratelimit_state),	\
417 			     "EXT4-fs error")
418 
419 void __ext4_error(struct super_block *sb, const char *function,
420 		  unsigned int line, const char *fmt, ...)
421 {
422 	struct va_format vaf;
423 	va_list args;
424 
425 	if (ext4_error_ratelimit(sb)) {
426 		va_start(args, fmt);
427 		vaf.fmt = fmt;
428 		vaf.va = &args;
429 		printk(KERN_CRIT
430 		       "EXT4-fs error (device %s): %s:%d: comm %s: %pV\n",
431 		       sb->s_id, function, line, current->comm, &vaf);
432 		va_end(args);
433 	}
434 	save_error_info(sb, function, line);
435 	ext4_handle_error(sb);
436 }
437 
438 void __ext4_error_inode(struct inode *inode, const char *function,
439 			unsigned int line, ext4_fsblk_t block,
440 			const char *fmt, ...)
441 {
442 	va_list args;
443 	struct va_format vaf;
444 	struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
445 
446 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
447 	es->s_last_error_block = cpu_to_le64(block);
448 	if (ext4_error_ratelimit(inode->i_sb)) {
449 		va_start(args, fmt);
450 		vaf.fmt = fmt;
451 		vaf.va = &args;
452 		if (block)
453 			printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
454 			       "inode #%lu: block %llu: comm %s: %pV\n",
455 			       inode->i_sb->s_id, function, line, inode->i_ino,
456 			       block, current->comm, &vaf);
457 		else
458 			printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
459 			       "inode #%lu: comm %s: %pV\n",
460 			       inode->i_sb->s_id, function, line, inode->i_ino,
461 			       current->comm, &vaf);
462 		va_end(args);
463 	}
464 	save_error_info(inode->i_sb, function, line);
465 	ext4_handle_error(inode->i_sb);
466 }
467 
468 void __ext4_error_file(struct file *file, const char *function,
469 		       unsigned int line, ext4_fsblk_t block,
470 		       const char *fmt, ...)
471 {
472 	va_list args;
473 	struct va_format vaf;
474 	struct ext4_super_block *es;
475 	struct inode *inode = file_inode(file);
476 	char pathname[80], *path;
477 
478 	es = EXT4_SB(inode->i_sb)->s_es;
479 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
480 	if (ext4_error_ratelimit(inode->i_sb)) {
481 		path = d_path(&(file->f_path), pathname, sizeof(pathname));
482 		if (IS_ERR(path))
483 			path = "(unknown)";
484 		va_start(args, fmt);
485 		vaf.fmt = fmt;
486 		vaf.va = &args;
487 		if (block)
488 			printk(KERN_CRIT
489 			       "EXT4-fs error (device %s): %s:%d: inode #%lu: "
490 			       "block %llu: comm %s: path %s: %pV\n",
491 			       inode->i_sb->s_id, function, line, inode->i_ino,
492 			       block, current->comm, path, &vaf);
493 		else
494 			printk(KERN_CRIT
495 			       "EXT4-fs error (device %s): %s:%d: inode #%lu: "
496 			       "comm %s: path %s: %pV\n",
497 			       inode->i_sb->s_id, function, line, inode->i_ino,
498 			       current->comm, path, &vaf);
499 		va_end(args);
500 	}
501 	save_error_info(inode->i_sb, function, line);
502 	ext4_handle_error(inode->i_sb);
503 }
504 
505 const char *ext4_decode_error(struct super_block *sb, int errno,
506 			      char nbuf[16])
507 {
508 	char *errstr = NULL;
509 
510 	switch (errno) {
511 	case -EIO:
512 		errstr = "IO failure";
513 		break;
514 	case -ENOMEM:
515 		errstr = "Out of memory";
516 		break;
517 	case -EROFS:
518 		if (!sb || (EXT4_SB(sb)->s_journal &&
519 			    EXT4_SB(sb)->s_journal->j_flags & JBD2_ABORT))
520 			errstr = "Journal has aborted";
521 		else
522 			errstr = "Readonly filesystem";
523 		break;
524 	default:
525 		/* If the caller passed in an extra buffer for unknown
526 		 * errors, textualise them now.  Else we just return
527 		 * NULL. */
528 		if (nbuf) {
529 			/* Check for truncated error codes... */
530 			if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
531 				errstr = nbuf;
532 		}
533 		break;
534 	}
535 
536 	return errstr;
537 }
538 
539 /* __ext4_std_error decodes expected errors from journaling functions
540  * automatically and invokes the appropriate error response.  */
541 
542 void __ext4_std_error(struct super_block *sb, const char *function,
543 		      unsigned int line, int errno)
544 {
545 	char nbuf[16];
546 	const char *errstr;
547 
548 	/* Special case: if the error is EROFS, and we're not already
549 	 * inside a transaction, then there's really no point in logging
550 	 * an error. */
551 	if (errno == -EROFS && journal_current_handle() == NULL &&
552 	    (sb->s_flags & MS_RDONLY))
553 		return;
554 
555 	if (ext4_error_ratelimit(sb)) {
556 		errstr = ext4_decode_error(sb, errno, nbuf);
557 		printk(KERN_CRIT "EXT4-fs error (device %s) in %s:%d: %s\n",
558 		       sb->s_id, function, line, errstr);
559 	}
560 
561 	save_error_info(sb, function, line);
562 	ext4_handle_error(sb);
563 }
564 
565 /*
566  * ext4_abort is a much stronger failure handler than ext4_error.  The
567  * abort function may be used to deal with unrecoverable failures such
568  * as journal IO errors or ENOMEM at a critical moment in log management.
569  *
570  * We unconditionally force the filesystem into an ABORT|READONLY state,
571  * unless the error response on the fs has been set to panic in which
572  * case we take the easy way out and panic immediately.
573  */
574 
575 void __ext4_abort(struct super_block *sb, const char *function,
576 		unsigned int line, const char *fmt, ...)
577 {
578 	va_list args;
579 
580 	save_error_info(sb, function, line);
581 	va_start(args, fmt);
582 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: ", sb->s_id,
583 	       function, line);
584 	vprintk(fmt, args);
585 	printk("\n");
586 	va_end(args);
587 
588 	if ((sb->s_flags & MS_RDONLY) == 0) {
589 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
590 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
591 		/*
592 		 * Make sure updated value of ->s_mount_flags will be visible
593 		 * before ->s_flags update
594 		 */
595 		smp_wmb();
596 		sb->s_flags |= MS_RDONLY;
597 		if (EXT4_SB(sb)->s_journal)
598 			jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
599 		save_error_info(sb, function, line);
600 	}
601 	if (test_opt(sb, ERRORS_PANIC))
602 		panic("EXT4-fs panic from previous error\n");
603 }
604 
605 void __ext4_msg(struct super_block *sb,
606 		const char *prefix, const char *fmt, ...)
607 {
608 	struct va_format vaf;
609 	va_list args;
610 
611 	if (!___ratelimit(&(EXT4_SB(sb)->s_msg_ratelimit_state), "EXT4-fs"))
612 		return;
613 
614 	va_start(args, fmt);
615 	vaf.fmt = fmt;
616 	vaf.va = &args;
617 	printk("%sEXT4-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
618 	va_end(args);
619 }
620 
621 void __ext4_warning(struct super_block *sb, const char *function,
622 		    unsigned int line, const char *fmt, ...)
623 {
624 	struct va_format vaf;
625 	va_list args;
626 
627 	if (!___ratelimit(&(EXT4_SB(sb)->s_warning_ratelimit_state),
628 			  "EXT4-fs warning"))
629 		return;
630 
631 	va_start(args, fmt);
632 	vaf.fmt = fmt;
633 	vaf.va = &args;
634 	printk(KERN_WARNING "EXT4-fs warning (device %s): %s:%d: %pV\n",
635 	       sb->s_id, function, line, &vaf);
636 	va_end(args);
637 }
638 
639 void __ext4_grp_locked_error(const char *function, unsigned int line,
640 			     struct super_block *sb, ext4_group_t grp,
641 			     unsigned long ino, ext4_fsblk_t block,
642 			     const char *fmt, ...)
643 __releases(bitlock)
644 __acquires(bitlock)
645 {
646 	struct va_format vaf;
647 	va_list args;
648 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
649 
650 	es->s_last_error_ino = cpu_to_le32(ino);
651 	es->s_last_error_block = cpu_to_le64(block);
652 	__save_error_info(sb, function, line);
653 
654 	if (ext4_error_ratelimit(sb)) {
655 		va_start(args, fmt);
656 		vaf.fmt = fmt;
657 		vaf.va = &args;
658 		printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: group %u, ",
659 		       sb->s_id, function, line, grp);
660 		if (ino)
661 			printk(KERN_CONT "inode %lu: ", ino);
662 		if (block)
663 			printk(KERN_CONT "block %llu:",
664 			       (unsigned long long) block);
665 		printk(KERN_CONT "%pV\n", &vaf);
666 		va_end(args);
667 	}
668 
669 	if (test_opt(sb, ERRORS_CONT)) {
670 		ext4_commit_super(sb, 0);
671 		return;
672 	}
673 
674 	ext4_unlock_group(sb, grp);
675 	ext4_handle_error(sb);
676 	/*
677 	 * We only get here in the ERRORS_RO case; relocking the group
678 	 * may be dangerous, but nothing bad will happen since the
679 	 * filesystem will have already been marked read/only and the
680 	 * journal has been aborted.  We return 1 as a hint to callers
681 	 * who might what to use the return value from
682 	 * ext4_grp_locked_error() to distinguish between the
683 	 * ERRORS_CONT and ERRORS_RO case, and perhaps return more
684 	 * aggressively from the ext4 function in question, with a
685 	 * more appropriate error code.
686 	 */
687 	ext4_lock_group(sb, grp);
688 	return;
689 }
690 
691 void ext4_update_dynamic_rev(struct super_block *sb)
692 {
693 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
694 
695 	if (le32_to_cpu(es->s_rev_level) > EXT4_GOOD_OLD_REV)
696 		return;
697 
698 	ext4_warning(sb,
699 		     "updating to rev %d because of new feature flag, "
700 		     "running e2fsck is recommended",
701 		     EXT4_DYNAMIC_REV);
702 
703 	es->s_first_ino = cpu_to_le32(EXT4_GOOD_OLD_FIRST_INO);
704 	es->s_inode_size = cpu_to_le16(EXT4_GOOD_OLD_INODE_SIZE);
705 	es->s_rev_level = cpu_to_le32(EXT4_DYNAMIC_REV);
706 	/* leave es->s_feature_*compat flags alone */
707 	/* es->s_uuid will be set by e2fsck if empty */
708 
709 	/*
710 	 * The rest of the superblock fields should be zero, and if not it
711 	 * means they are likely already in use, so leave them alone.  We
712 	 * can leave it up to e2fsck to clean up any inconsistencies there.
713 	 */
714 }
715 
716 /*
717  * Open the external journal device
718  */
719 static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb)
720 {
721 	struct block_device *bdev;
722 	char b[BDEVNAME_SIZE];
723 
724 	bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb);
725 	if (IS_ERR(bdev))
726 		goto fail;
727 	return bdev;
728 
729 fail:
730 	ext4_msg(sb, KERN_ERR, "failed to open journal device %s: %ld",
731 			__bdevname(dev, b), PTR_ERR(bdev));
732 	return NULL;
733 }
734 
735 /*
736  * Release the journal device
737  */
738 static void ext4_blkdev_put(struct block_device *bdev)
739 {
740 	blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
741 }
742 
743 static void ext4_blkdev_remove(struct ext4_sb_info *sbi)
744 {
745 	struct block_device *bdev;
746 	bdev = sbi->journal_bdev;
747 	if (bdev) {
748 		ext4_blkdev_put(bdev);
749 		sbi->journal_bdev = NULL;
750 	}
751 }
752 
753 static inline struct inode *orphan_list_entry(struct list_head *l)
754 {
755 	return &list_entry(l, struct ext4_inode_info, i_orphan)->vfs_inode;
756 }
757 
758 static void dump_orphan_list(struct super_block *sb, struct ext4_sb_info *sbi)
759 {
760 	struct list_head *l;
761 
762 	ext4_msg(sb, KERN_ERR, "sb orphan head is %d",
763 		 le32_to_cpu(sbi->s_es->s_last_orphan));
764 
765 	printk(KERN_ERR "sb_info orphan list:\n");
766 	list_for_each(l, &sbi->s_orphan) {
767 		struct inode *inode = orphan_list_entry(l);
768 		printk(KERN_ERR "  "
769 		       "inode %s:%lu at %p: mode %o, nlink %d, next %d\n",
770 		       inode->i_sb->s_id, inode->i_ino, inode,
771 		       inode->i_mode, inode->i_nlink,
772 		       NEXT_ORPHAN(inode));
773 	}
774 }
775 
776 static void ext4_put_super(struct super_block *sb)
777 {
778 	struct ext4_sb_info *sbi = EXT4_SB(sb);
779 	struct ext4_super_block *es = sbi->s_es;
780 	int i, err;
781 
782 	ext4_unregister_li_request(sb);
783 	dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
784 
785 	flush_workqueue(sbi->rsv_conversion_wq);
786 	destroy_workqueue(sbi->rsv_conversion_wq);
787 
788 	if (sbi->s_journal) {
789 		err = jbd2_journal_destroy(sbi->s_journal);
790 		sbi->s_journal = NULL;
791 		if (err < 0)
792 			ext4_abort(sb, "Couldn't clean up the journal");
793 	}
794 
795 	ext4_es_unregister_shrinker(sbi);
796 	del_timer_sync(&sbi->s_err_report);
797 	ext4_release_system_zone(sb);
798 	ext4_mb_release(sb);
799 	ext4_ext_release(sb);
800 	ext4_xattr_put_super(sb);
801 
802 	if (!(sb->s_flags & MS_RDONLY)) {
803 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
804 		es->s_state = cpu_to_le16(sbi->s_mount_state);
805 	}
806 	if (!(sb->s_flags & MS_RDONLY))
807 		ext4_commit_super(sb, 1);
808 
809 	if (sbi->s_proc) {
810 		remove_proc_entry("options", sbi->s_proc);
811 		remove_proc_entry(sb->s_id, ext4_proc_root);
812 	}
813 	kobject_del(&sbi->s_kobj);
814 
815 	for (i = 0; i < sbi->s_gdb_count; i++)
816 		brelse(sbi->s_group_desc[i]);
817 	ext4_kvfree(sbi->s_group_desc);
818 	ext4_kvfree(sbi->s_flex_groups);
819 	percpu_counter_destroy(&sbi->s_freeclusters_counter);
820 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
821 	percpu_counter_destroy(&sbi->s_dirs_counter);
822 	percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
823 	percpu_counter_destroy(&sbi->s_extent_cache_cnt);
824 	brelse(sbi->s_sbh);
825 #ifdef CONFIG_QUOTA
826 	for (i = 0; i < MAXQUOTAS; i++)
827 		kfree(sbi->s_qf_names[i]);
828 #endif
829 
830 	/* Debugging code just in case the in-memory inode orphan list
831 	 * isn't empty.  The on-disk one can be non-empty if we've
832 	 * detected an error and taken the fs readonly, but the
833 	 * in-memory list had better be clean by this point. */
834 	if (!list_empty(&sbi->s_orphan))
835 		dump_orphan_list(sb, sbi);
836 	J_ASSERT(list_empty(&sbi->s_orphan));
837 
838 	invalidate_bdev(sb->s_bdev);
839 	if (sbi->journal_bdev && sbi->journal_bdev != sb->s_bdev) {
840 		/*
841 		 * Invalidate the journal device's buffers.  We don't want them
842 		 * floating about in memory - the physical journal device may
843 		 * hotswapped, and it breaks the `ro-after' testing code.
844 		 */
845 		sync_blockdev(sbi->journal_bdev);
846 		invalidate_bdev(sbi->journal_bdev);
847 		ext4_blkdev_remove(sbi);
848 	}
849 	if (sbi->s_mb_cache) {
850 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
851 		sbi->s_mb_cache = NULL;
852 	}
853 	if (sbi->s_mmp_tsk)
854 		kthread_stop(sbi->s_mmp_tsk);
855 	sb->s_fs_info = NULL;
856 	/*
857 	 * Now that we are completely done shutting down the
858 	 * superblock, we need to actually destroy the kobject.
859 	 */
860 	kobject_put(&sbi->s_kobj);
861 	wait_for_completion(&sbi->s_kobj_unregister);
862 	if (sbi->s_chksum_driver)
863 		crypto_free_shash(sbi->s_chksum_driver);
864 	kfree(sbi->s_blockgroup_lock);
865 	kfree(sbi);
866 }
867 
868 static struct kmem_cache *ext4_inode_cachep;
869 
870 /*
871  * Called inside transaction, so use GFP_NOFS
872  */
873 static struct inode *ext4_alloc_inode(struct super_block *sb)
874 {
875 	struct ext4_inode_info *ei;
876 
877 	ei = kmem_cache_alloc(ext4_inode_cachep, GFP_NOFS);
878 	if (!ei)
879 		return NULL;
880 
881 	ei->vfs_inode.i_version = 1;
882 	spin_lock_init(&ei->i_raw_lock);
883 	INIT_LIST_HEAD(&ei->i_prealloc_list);
884 	spin_lock_init(&ei->i_prealloc_lock);
885 	ext4_es_init_tree(&ei->i_es_tree);
886 	rwlock_init(&ei->i_es_lock);
887 	INIT_LIST_HEAD(&ei->i_es_lru);
888 	ei->i_es_lru_nr = 0;
889 	ei->i_touch_when = 0;
890 	ei->i_reserved_data_blocks = 0;
891 	ei->i_reserved_meta_blocks = 0;
892 	ei->i_allocated_meta_blocks = 0;
893 	ei->i_da_metadata_calc_len = 0;
894 	ei->i_da_metadata_calc_last_lblock = 0;
895 	spin_lock_init(&(ei->i_block_reservation_lock));
896 #ifdef CONFIG_QUOTA
897 	ei->i_reserved_quota = 0;
898 #endif
899 	ei->jinode = NULL;
900 	INIT_LIST_HEAD(&ei->i_rsv_conversion_list);
901 	spin_lock_init(&ei->i_completed_io_lock);
902 	ei->i_sync_tid = 0;
903 	ei->i_datasync_tid = 0;
904 	atomic_set(&ei->i_ioend_count, 0);
905 	atomic_set(&ei->i_unwritten, 0);
906 	INIT_WORK(&ei->i_rsv_conversion_work, ext4_end_io_rsv_work);
907 
908 	return &ei->vfs_inode;
909 }
910 
911 static int ext4_drop_inode(struct inode *inode)
912 {
913 	int drop = generic_drop_inode(inode);
914 
915 	trace_ext4_drop_inode(inode, drop);
916 	return drop;
917 }
918 
919 static void ext4_i_callback(struct rcu_head *head)
920 {
921 	struct inode *inode = container_of(head, struct inode, i_rcu);
922 	kmem_cache_free(ext4_inode_cachep, EXT4_I(inode));
923 }
924 
925 static void ext4_destroy_inode(struct inode *inode)
926 {
927 	if (!list_empty(&(EXT4_I(inode)->i_orphan))) {
928 		ext4_msg(inode->i_sb, KERN_ERR,
929 			 "Inode %lu (%p): orphan list check failed!",
930 			 inode->i_ino, EXT4_I(inode));
931 		print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 16, 4,
932 				EXT4_I(inode), sizeof(struct ext4_inode_info),
933 				true);
934 		dump_stack();
935 	}
936 	call_rcu(&inode->i_rcu, ext4_i_callback);
937 }
938 
939 static void init_once(void *foo)
940 {
941 	struct ext4_inode_info *ei = (struct ext4_inode_info *) foo;
942 
943 	INIT_LIST_HEAD(&ei->i_orphan);
944 	init_rwsem(&ei->xattr_sem);
945 	init_rwsem(&ei->i_data_sem);
946 	inode_init_once(&ei->vfs_inode);
947 }
948 
949 static int __init init_inodecache(void)
950 {
951 	ext4_inode_cachep = kmem_cache_create("ext4_inode_cache",
952 					     sizeof(struct ext4_inode_info),
953 					     0, (SLAB_RECLAIM_ACCOUNT|
954 						SLAB_MEM_SPREAD),
955 					     init_once);
956 	if (ext4_inode_cachep == NULL)
957 		return -ENOMEM;
958 	return 0;
959 }
960 
961 static void destroy_inodecache(void)
962 {
963 	/*
964 	 * Make sure all delayed rcu free inodes are flushed before we
965 	 * destroy cache.
966 	 */
967 	rcu_barrier();
968 	kmem_cache_destroy(ext4_inode_cachep);
969 }
970 
971 void ext4_clear_inode(struct inode *inode)
972 {
973 	invalidate_inode_buffers(inode);
974 	clear_inode(inode);
975 	dquot_drop(inode);
976 	ext4_discard_preallocations(inode);
977 	ext4_es_remove_extent(inode, 0, EXT_MAX_BLOCKS);
978 	ext4_es_lru_del(inode);
979 	if (EXT4_I(inode)->jinode) {
980 		jbd2_journal_release_jbd_inode(EXT4_JOURNAL(inode),
981 					       EXT4_I(inode)->jinode);
982 		jbd2_free_inode(EXT4_I(inode)->jinode);
983 		EXT4_I(inode)->jinode = NULL;
984 	}
985 }
986 
987 static struct inode *ext4_nfs_get_inode(struct super_block *sb,
988 					u64 ino, u32 generation)
989 {
990 	struct inode *inode;
991 
992 	if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
993 		return ERR_PTR(-ESTALE);
994 	if (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
995 		return ERR_PTR(-ESTALE);
996 
997 	/* iget isn't really right if the inode is currently unallocated!!
998 	 *
999 	 * ext4_read_inode will return a bad_inode if the inode had been
1000 	 * deleted, so we should be safe.
1001 	 *
1002 	 * Currently we don't know the generation for parent directory, so
1003 	 * a generation of 0 means "accept any"
1004 	 */
1005 	inode = ext4_iget(sb, ino);
1006 	if (IS_ERR(inode))
1007 		return ERR_CAST(inode);
1008 	if (generation && inode->i_generation != generation) {
1009 		iput(inode);
1010 		return ERR_PTR(-ESTALE);
1011 	}
1012 
1013 	return inode;
1014 }
1015 
1016 static struct dentry *ext4_fh_to_dentry(struct super_block *sb, struct fid *fid,
1017 					int fh_len, int fh_type)
1018 {
1019 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
1020 				    ext4_nfs_get_inode);
1021 }
1022 
1023 static struct dentry *ext4_fh_to_parent(struct super_block *sb, struct fid *fid,
1024 					int fh_len, int fh_type)
1025 {
1026 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
1027 				    ext4_nfs_get_inode);
1028 }
1029 
1030 /*
1031  * Try to release metadata pages (indirect blocks, directories) which are
1032  * mapped via the block device.  Since these pages could have journal heads
1033  * which would prevent try_to_free_buffers() from freeing them, we must use
1034  * jbd2 layer's try_to_free_buffers() function to release them.
1035  */
1036 static int bdev_try_to_free_page(struct super_block *sb, struct page *page,
1037 				 gfp_t wait)
1038 {
1039 	journal_t *journal = EXT4_SB(sb)->s_journal;
1040 
1041 	WARN_ON(PageChecked(page));
1042 	if (!page_has_buffers(page))
1043 		return 0;
1044 	if (journal)
1045 		return jbd2_journal_try_to_free_buffers(journal, page,
1046 							wait & ~__GFP_WAIT);
1047 	return try_to_free_buffers(page);
1048 }
1049 
1050 #ifdef CONFIG_QUOTA
1051 #define QTYPE2NAME(t) ((t) == USRQUOTA ? "user" : "group")
1052 #define QTYPE2MOPT(on, t) ((t) == USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
1053 
1054 static int ext4_write_dquot(struct dquot *dquot);
1055 static int ext4_acquire_dquot(struct dquot *dquot);
1056 static int ext4_release_dquot(struct dquot *dquot);
1057 static int ext4_mark_dquot_dirty(struct dquot *dquot);
1058 static int ext4_write_info(struct super_block *sb, int type);
1059 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
1060 			 struct path *path);
1061 static int ext4_quota_on_sysfile(struct super_block *sb, int type,
1062 				 int format_id);
1063 static int ext4_quota_off(struct super_block *sb, int type);
1064 static int ext4_quota_off_sysfile(struct super_block *sb, int type);
1065 static int ext4_quota_on_mount(struct super_block *sb, int type);
1066 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
1067 			       size_t len, loff_t off);
1068 static ssize_t ext4_quota_write(struct super_block *sb, int type,
1069 				const char *data, size_t len, loff_t off);
1070 static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
1071 			     unsigned int flags);
1072 static int ext4_enable_quotas(struct super_block *sb);
1073 
1074 static const struct dquot_operations ext4_quota_operations = {
1075 	.get_reserved_space = ext4_get_reserved_space,
1076 	.write_dquot	= ext4_write_dquot,
1077 	.acquire_dquot	= ext4_acquire_dquot,
1078 	.release_dquot	= ext4_release_dquot,
1079 	.mark_dirty	= ext4_mark_dquot_dirty,
1080 	.write_info	= ext4_write_info,
1081 	.alloc_dquot	= dquot_alloc,
1082 	.destroy_dquot	= dquot_destroy,
1083 };
1084 
1085 static const struct quotactl_ops ext4_qctl_operations = {
1086 	.quota_on	= ext4_quota_on,
1087 	.quota_off	= ext4_quota_off,
1088 	.quota_sync	= dquot_quota_sync,
1089 	.get_info	= dquot_get_dqinfo,
1090 	.set_info	= dquot_set_dqinfo,
1091 	.get_dqblk	= dquot_get_dqblk,
1092 	.set_dqblk	= dquot_set_dqblk
1093 };
1094 
1095 static const struct quotactl_ops ext4_qctl_sysfile_operations = {
1096 	.quota_on_meta	= ext4_quota_on_sysfile,
1097 	.quota_off	= ext4_quota_off_sysfile,
1098 	.quota_sync	= dquot_quota_sync,
1099 	.get_info	= dquot_get_dqinfo,
1100 	.set_info	= dquot_set_dqinfo,
1101 	.get_dqblk	= dquot_get_dqblk,
1102 	.set_dqblk	= dquot_set_dqblk
1103 };
1104 #endif
1105 
1106 static const struct super_operations ext4_sops = {
1107 	.alloc_inode	= ext4_alloc_inode,
1108 	.destroy_inode	= ext4_destroy_inode,
1109 	.write_inode	= ext4_write_inode,
1110 	.dirty_inode	= ext4_dirty_inode,
1111 	.drop_inode	= ext4_drop_inode,
1112 	.evict_inode	= ext4_evict_inode,
1113 	.put_super	= ext4_put_super,
1114 	.sync_fs	= ext4_sync_fs,
1115 	.freeze_fs	= ext4_freeze,
1116 	.unfreeze_fs	= ext4_unfreeze,
1117 	.statfs		= ext4_statfs,
1118 	.remount_fs	= ext4_remount,
1119 	.show_options	= ext4_show_options,
1120 #ifdef CONFIG_QUOTA
1121 	.quota_read	= ext4_quota_read,
1122 	.quota_write	= ext4_quota_write,
1123 #endif
1124 	.bdev_try_to_free_page = bdev_try_to_free_page,
1125 };
1126 
1127 static const struct super_operations ext4_nojournal_sops = {
1128 	.alloc_inode	= ext4_alloc_inode,
1129 	.destroy_inode	= ext4_destroy_inode,
1130 	.write_inode	= ext4_write_inode,
1131 	.dirty_inode	= ext4_dirty_inode,
1132 	.drop_inode	= ext4_drop_inode,
1133 	.evict_inode	= ext4_evict_inode,
1134 	.sync_fs	= ext4_sync_fs_nojournal,
1135 	.put_super	= ext4_put_super,
1136 	.statfs		= ext4_statfs,
1137 	.remount_fs	= ext4_remount,
1138 	.show_options	= ext4_show_options,
1139 #ifdef CONFIG_QUOTA
1140 	.quota_read	= ext4_quota_read,
1141 	.quota_write	= ext4_quota_write,
1142 #endif
1143 	.bdev_try_to_free_page = bdev_try_to_free_page,
1144 };
1145 
1146 static const struct export_operations ext4_export_ops = {
1147 	.fh_to_dentry = ext4_fh_to_dentry,
1148 	.fh_to_parent = ext4_fh_to_parent,
1149 	.get_parent = ext4_get_parent,
1150 };
1151 
1152 enum {
1153 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
1154 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
1155 	Opt_nouid32, Opt_debug, Opt_removed,
1156 	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
1157 	Opt_auto_da_alloc, Opt_noauto_da_alloc, Opt_noload,
1158 	Opt_commit, Opt_min_batch_time, Opt_max_batch_time, Opt_journal_dev,
1159 	Opt_journal_path, Opt_journal_checksum, Opt_journal_async_commit,
1160 	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
1161 	Opt_data_err_abort, Opt_data_err_ignore,
1162 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
1163 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
1164 	Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err,
1165 	Opt_usrquota, Opt_grpquota, Opt_i_version,
1166 	Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_mblk_io_submit,
1167 	Opt_nomblk_io_submit, Opt_block_validity, Opt_noblock_validity,
1168 	Opt_inode_readahead_blks, Opt_journal_ioprio,
1169 	Opt_dioread_nolock, Opt_dioread_lock,
1170 	Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
1171 	Opt_max_dir_size_kb,
1172 };
1173 
1174 static const match_table_t tokens = {
1175 	{Opt_bsd_df, "bsddf"},
1176 	{Opt_minix_df, "minixdf"},
1177 	{Opt_grpid, "grpid"},
1178 	{Opt_grpid, "bsdgroups"},
1179 	{Opt_nogrpid, "nogrpid"},
1180 	{Opt_nogrpid, "sysvgroups"},
1181 	{Opt_resgid, "resgid=%u"},
1182 	{Opt_resuid, "resuid=%u"},
1183 	{Opt_sb, "sb=%u"},
1184 	{Opt_err_cont, "errors=continue"},
1185 	{Opt_err_panic, "errors=panic"},
1186 	{Opt_err_ro, "errors=remount-ro"},
1187 	{Opt_nouid32, "nouid32"},
1188 	{Opt_debug, "debug"},
1189 	{Opt_removed, "oldalloc"},
1190 	{Opt_removed, "orlov"},
1191 	{Opt_user_xattr, "user_xattr"},
1192 	{Opt_nouser_xattr, "nouser_xattr"},
1193 	{Opt_acl, "acl"},
1194 	{Opt_noacl, "noacl"},
1195 	{Opt_noload, "norecovery"},
1196 	{Opt_noload, "noload"},
1197 	{Opt_removed, "nobh"},
1198 	{Opt_removed, "bh"},
1199 	{Opt_commit, "commit=%u"},
1200 	{Opt_min_batch_time, "min_batch_time=%u"},
1201 	{Opt_max_batch_time, "max_batch_time=%u"},
1202 	{Opt_journal_dev, "journal_dev=%u"},
1203 	{Opt_journal_path, "journal_path=%s"},
1204 	{Opt_journal_checksum, "journal_checksum"},
1205 	{Opt_journal_async_commit, "journal_async_commit"},
1206 	{Opt_abort, "abort"},
1207 	{Opt_data_journal, "data=journal"},
1208 	{Opt_data_ordered, "data=ordered"},
1209 	{Opt_data_writeback, "data=writeback"},
1210 	{Opt_data_err_abort, "data_err=abort"},
1211 	{Opt_data_err_ignore, "data_err=ignore"},
1212 	{Opt_offusrjquota, "usrjquota="},
1213 	{Opt_usrjquota, "usrjquota=%s"},
1214 	{Opt_offgrpjquota, "grpjquota="},
1215 	{Opt_grpjquota, "grpjquota=%s"},
1216 	{Opt_jqfmt_vfsold, "jqfmt=vfsold"},
1217 	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
1218 	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
1219 	{Opt_grpquota, "grpquota"},
1220 	{Opt_noquota, "noquota"},
1221 	{Opt_quota, "quota"},
1222 	{Opt_usrquota, "usrquota"},
1223 	{Opt_barrier, "barrier=%u"},
1224 	{Opt_barrier, "barrier"},
1225 	{Opt_nobarrier, "nobarrier"},
1226 	{Opt_i_version, "i_version"},
1227 	{Opt_stripe, "stripe=%u"},
1228 	{Opt_delalloc, "delalloc"},
1229 	{Opt_nodelalloc, "nodelalloc"},
1230 	{Opt_removed, "mblk_io_submit"},
1231 	{Opt_removed, "nomblk_io_submit"},
1232 	{Opt_block_validity, "block_validity"},
1233 	{Opt_noblock_validity, "noblock_validity"},
1234 	{Opt_inode_readahead_blks, "inode_readahead_blks=%u"},
1235 	{Opt_journal_ioprio, "journal_ioprio=%u"},
1236 	{Opt_auto_da_alloc, "auto_da_alloc=%u"},
1237 	{Opt_auto_da_alloc, "auto_da_alloc"},
1238 	{Opt_noauto_da_alloc, "noauto_da_alloc"},
1239 	{Opt_dioread_nolock, "dioread_nolock"},
1240 	{Opt_dioread_lock, "dioread_lock"},
1241 	{Opt_discard, "discard"},
1242 	{Opt_nodiscard, "nodiscard"},
1243 	{Opt_init_itable, "init_itable=%u"},
1244 	{Opt_init_itable, "init_itable"},
1245 	{Opt_noinit_itable, "noinit_itable"},
1246 	{Opt_max_dir_size_kb, "max_dir_size_kb=%u"},
1247 	{Opt_removed, "check=none"},	/* mount option from ext2/3 */
1248 	{Opt_removed, "nocheck"},	/* mount option from ext2/3 */
1249 	{Opt_removed, "reservation"},	/* mount option from ext2/3 */
1250 	{Opt_removed, "noreservation"}, /* mount option from ext2/3 */
1251 	{Opt_removed, "journal=%u"},	/* mount option from ext2/3 */
1252 	{Opt_err, NULL},
1253 };
1254 
1255 static ext4_fsblk_t get_sb_block(void **data)
1256 {
1257 	ext4_fsblk_t	sb_block;
1258 	char		*options = (char *) *data;
1259 
1260 	if (!options || strncmp(options, "sb=", 3) != 0)
1261 		return 1;	/* Default location */
1262 
1263 	options += 3;
1264 	/* TODO: use simple_strtoll with >32bit ext4 */
1265 	sb_block = simple_strtoul(options, &options, 0);
1266 	if (*options && *options != ',') {
1267 		printk(KERN_ERR "EXT4-fs: Invalid sb specification: %s\n",
1268 		       (char *) *data);
1269 		return 1;
1270 	}
1271 	if (*options == ',')
1272 		options++;
1273 	*data = (void *) options;
1274 
1275 	return sb_block;
1276 }
1277 
1278 #define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))
1279 static char deprecated_msg[] = "Mount option \"%s\" will be removed by %s\n"
1280 	"Contact linux-ext4@vger.kernel.org if you think we should keep it.\n";
1281 
1282 #ifdef CONFIG_QUOTA
1283 static int set_qf_name(struct super_block *sb, int qtype, substring_t *args)
1284 {
1285 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1286 	char *qname;
1287 	int ret = -1;
1288 
1289 	if (sb_any_quota_loaded(sb) &&
1290 		!sbi->s_qf_names[qtype]) {
1291 		ext4_msg(sb, KERN_ERR,
1292 			"Cannot change journaled "
1293 			"quota options when quota turned on");
1294 		return -1;
1295 	}
1296 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA)) {
1297 		ext4_msg(sb, KERN_ERR, "Cannot set journaled quota options "
1298 			 "when QUOTA feature is enabled");
1299 		return -1;
1300 	}
1301 	qname = match_strdup(args);
1302 	if (!qname) {
1303 		ext4_msg(sb, KERN_ERR,
1304 			"Not enough memory for storing quotafile name");
1305 		return -1;
1306 	}
1307 	if (sbi->s_qf_names[qtype]) {
1308 		if (strcmp(sbi->s_qf_names[qtype], qname) == 0)
1309 			ret = 1;
1310 		else
1311 			ext4_msg(sb, KERN_ERR,
1312 				 "%s quota file already specified",
1313 				 QTYPE2NAME(qtype));
1314 		goto errout;
1315 	}
1316 	if (strchr(qname, '/')) {
1317 		ext4_msg(sb, KERN_ERR,
1318 			"quotafile must be on filesystem root");
1319 		goto errout;
1320 	}
1321 	sbi->s_qf_names[qtype] = qname;
1322 	set_opt(sb, QUOTA);
1323 	return 1;
1324 errout:
1325 	kfree(qname);
1326 	return ret;
1327 }
1328 
1329 static int clear_qf_name(struct super_block *sb, int qtype)
1330 {
1331 
1332 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1333 
1334 	if (sb_any_quota_loaded(sb) &&
1335 		sbi->s_qf_names[qtype]) {
1336 		ext4_msg(sb, KERN_ERR, "Cannot change journaled quota options"
1337 			" when quota turned on");
1338 		return -1;
1339 	}
1340 	kfree(sbi->s_qf_names[qtype]);
1341 	sbi->s_qf_names[qtype] = NULL;
1342 	return 1;
1343 }
1344 #endif
1345 
1346 #define MOPT_SET	0x0001
1347 #define MOPT_CLEAR	0x0002
1348 #define MOPT_NOSUPPORT	0x0004
1349 #define MOPT_EXPLICIT	0x0008
1350 #define MOPT_CLEAR_ERR	0x0010
1351 #define MOPT_GTE0	0x0020
1352 #ifdef CONFIG_QUOTA
1353 #define MOPT_Q		0
1354 #define MOPT_QFMT	0x0040
1355 #else
1356 #define MOPT_Q		MOPT_NOSUPPORT
1357 #define MOPT_QFMT	MOPT_NOSUPPORT
1358 #endif
1359 #define MOPT_DATAJ	0x0080
1360 #define MOPT_NO_EXT2	0x0100
1361 #define MOPT_NO_EXT3	0x0200
1362 #define MOPT_EXT4_ONLY	(MOPT_NO_EXT2 | MOPT_NO_EXT3)
1363 #define MOPT_STRING	0x0400
1364 
1365 static const struct mount_opts {
1366 	int	token;
1367 	int	mount_opt;
1368 	int	flags;
1369 } ext4_mount_opts[] = {
1370 	{Opt_minix_df, EXT4_MOUNT_MINIX_DF, MOPT_SET},
1371 	{Opt_bsd_df, EXT4_MOUNT_MINIX_DF, MOPT_CLEAR},
1372 	{Opt_grpid, EXT4_MOUNT_GRPID, MOPT_SET},
1373 	{Opt_nogrpid, EXT4_MOUNT_GRPID, MOPT_CLEAR},
1374 	{Opt_block_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_SET},
1375 	{Opt_noblock_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_CLEAR},
1376 	{Opt_dioread_nolock, EXT4_MOUNT_DIOREAD_NOLOCK,
1377 	 MOPT_EXT4_ONLY | MOPT_SET},
1378 	{Opt_dioread_lock, EXT4_MOUNT_DIOREAD_NOLOCK,
1379 	 MOPT_EXT4_ONLY | MOPT_CLEAR},
1380 	{Opt_discard, EXT4_MOUNT_DISCARD, MOPT_SET},
1381 	{Opt_nodiscard, EXT4_MOUNT_DISCARD, MOPT_CLEAR},
1382 	{Opt_delalloc, EXT4_MOUNT_DELALLOC,
1383 	 MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
1384 	{Opt_nodelalloc, EXT4_MOUNT_DELALLOC,
1385 	 MOPT_EXT4_ONLY | MOPT_CLEAR},
1386 	{Opt_journal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,
1387 	 MOPT_EXT4_ONLY | MOPT_SET},
1388 	{Opt_journal_async_commit, (EXT4_MOUNT_JOURNAL_ASYNC_COMMIT |
1389 				    EXT4_MOUNT_JOURNAL_CHECKSUM),
1390 	 MOPT_EXT4_ONLY | MOPT_SET},
1391 	{Opt_noload, EXT4_MOUNT_NOLOAD, MOPT_NO_EXT2 | MOPT_SET},
1392 	{Opt_err_panic, EXT4_MOUNT_ERRORS_PANIC, MOPT_SET | MOPT_CLEAR_ERR},
1393 	{Opt_err_ro, EXT4_MOUNT_ERRORS_RO, MOPT_SET | MOPT_CLEAR_ERR},
1394 	{Opt_err_cont, EXT4_MOUNT_ERRORS_CONT, MOPT_SET | MOPT_CLEAR_ERR},
1395 	{Opt_data_err_abort, EXT4_MOUNT_DATA_ERR_ABORT,
1396 	 MOPT_NO_EXT2 | MOPT_SET},
1397 	{Opt_data_err_ignore, EXT4_MOUNT_DATA_ERR_ABORT,
1398 	 MOPT_NO_EXT2 | MOPT_CLEAR},
1399 	{Opt_barrier, EXT4_MOUNT_BARRIER, MOPT_SET},
1400 	{Opt_nobarrier, EXT4_MOUNT_BARRIER, MOPT_CLEAR},
1401 	{Opt_noauto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_SET},
1402 	{Opt_auto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_CLEAR},
1403 	{Opt_noinit_itable, EXT4_MOUNT_INIT_INODE_TABLE, MOPT_CLEAR},
1404 	{Opt_commit, 0, MOPT_GTE0},
1405 	{Opt_max_batch_time, 0, MOPT_GTE0},
1406 	{Opt_min_batch_time, 0, MOPT_GTE0},
1407 	{Opt_inode_readahead_blks, 0, MOPT_GTE0},
1408 	{Opt_init_itable, 0, MOPT_GTE0},
1409 	{Opt_stripe, 0, MOPT_GTE0},
1410 	{Opt_resuid, 0, MOPT_GTE0},
1411 	{Opt_resgid, 0, MOPT_GTE0},
1412 	{Opt_journal_dev, 0, MOPT_GTE0},
1413 	{Opt_journal_path, 0, MOPT_STRING},
1414 	{Opt_journal_ioprio, 0, MOPT_GTE0},
1415 	{Opt_data_journal, EXT4_MOUNT_JOURNAL_DATA, MOPT_NO_EXT2 | MOPT_DATAJ},
1416 	{Opt_data_ordered, EXT4_MOUNT_ORDERED_DATA, MOPT_NO_EXT2 | MOPT_DATAJ},
1417 	{Opt_data_writeback, EXT4_MOUNT_WRITEBACK_DATA,
1418 	 MOPT_NO_EXT2 | MOPT_DATAJ},
1419 	{Opt_user_xattr, EXT4_MOUNT_XATTR_USER, MOPT_SET},
1420 	{Opt_nouser_xattr, EXT4_MOUNT_XATTR_USER, MOPT_CLEAR},
1421 #ifdef CONFIG_EXT4_FS_POSIX_ACL
1422 	{Opt_acl, EXT4_MOUNT_POSIX_ACL, MOPT_SET},
1423 	{Opt_noacl, EXT4_MOUNT_POSIX_ACL, MOPT_CLEAR},
1424 #else
1425 	{Opt_acl, 0, MOPT_NOSUPPORT},
1426 	{Opt_noacl, 0, MOPT_NOSUPPORT},
1427 #endif
1428 	{Opt_nouid32, EXT4_MOUNT_NO_UID32, MOPT_SET},
1429 	{Opt_debug, EXT4_MOUNT_DEBUG, MOPT_SET},
1430 	{Opt_quota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA, MOPT_SET | MOPT_Q},
1431 	{Opt_usrquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA,
1432 							MOPT_SET | MOPT_Q},
1433 	{Opt_grpquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_GRPQUOTA,
1434 							MOPT_SET | MOPT_Q},
1435 	{Opt_noquota, (EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA |
1436 		       EXT4_MOUNT_GRPQUOTA), MOPT_CLEAR | MOPT_Q},
1437 	{Opt_usrjquota, 0, MOPT_Q},
1438 	{Opt_grpjquota, 0, MOPT_Q},
1439 	{Opt_offusrjquota, 0, MOPT_Q},
1440 	{Opt_offgrpjquota, 0, MOPT_Q},
1441 	{Opt_jqfmt_vfsold, QFMT_VFS_OLD, MOPT_QFMT},
1442 	{Opt_jqfmt_vfsv0, QFMT_VFS_V0, MOPT_QFMT},
1443 	{Opt_jqfmt_vfsv1, QFMT_VFS_V1, MOPT_QFMT},
1444 	{Opt_max_dir_size_kb, 0, MOPT_GTE0},
1445 	{Opt_err, 0, 0}
1446 };
1447 
1448 static int handle_mount_opt(struct super_block *sb, char *opt, int token,
1449 			    substring_t *args, unsigned long *journal_devnum,
1450 			    unsigned int *journal_ioprio, int is_remount)
1451 {
1452 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1453 	const struct mount_opts *m;
1454 	kuid_t uid;
1455 	kgid_t gid;
1456 	int arg = 0;
1457 
1458 #ifdef CONFIG_QUOTA
1459 	if (token == Opt_usrjquota)
1460 		return set_qf_name(sb, USRQUOTA, &args[0]);
1461 	else if (token == Opt_grpjquota)
1462 		return set_qf_name(sb, GRPQUOTA, &args[0]);
1463 	else if (token == Opt_offusrjquota)
1464 		return clear_qf_name(sb, USRQUOTA);
1465 	else if (token == Opt_offgrpjquota)
1466 		return clear_qf_name(sb, GRPQUOTA);
1467 #endif
1468 	switch (token) {
1469 	case Opt_noacl:
1470 	case Opt_nouser_xattr:
1471 		ext4_msg(sb, KERN_WARNING, deprecated_msg, opt, "3.5");
1472 		break;
1473 	case Opt_sb:
1474 		return 1;	/* handled by get_sb_block() */
1475 	case Opt_removed:
1476 		ext4_msg(sb, KERN_WARNING, "Ignoring removed %s option", opt);
1477 		return 1;
1478 	case Opt_abort:
1479 		sbi->s_mount_flags |= EXT4_MF_FS_ABORTED;
1480 		return 1;
1481 	case Opt_i_version:
1482 		sb->s_flags |= MS_I_VERSION;
1483 		return 1;
1484 	}
1485 
1486 	for (m = ext4_mount_opts; m->token != Opt_err; m++)
1487 		if (token == m->token)
1488 			break;
1489 
1490 	if (m->token == Opt_err) {
1491 		ext4_msg(sb, KERN_ERR, "Unrecognized mount option \"%s\" "
1492 			 "or missing value", opt);
1493 		return -1;
1494 	}
1495 
1496 	if ((m->flags & MOPT_NO_EXT2) && IS_EXT2_SB(sb)) {
1497 		ext4_msg(sb, KERN_ERR,
1498 			 "Mount option \"%s\" incompatible with ext2", opt);
1499 		return -1;
1500 	}
1501 	if ((m->flags & MOPT_NO_EXT3) && IS_EXT3_SB(sb)) {
1502 		ext4_msg(sb, KERN_ERR,
1503 			 "Mount option \"%s\" incompatible with ext3", opt);
1504 		return -1;
1505 	}
1506 
1507 	if (args->from && !(m->flags & MOPT_STRING) && match_int(args, &arg))
1508 		return -1;
1509 	if (args->from && (m->flags & MOPT_GTE0) && (arg < 0))
1510 		return -1;
1511 	if (m->flags & MOPT_EXPLICIT)
1512 		set_opt2(sb, EXPLICIT_DELALLOC);
1513 	if (m->flags & MOPT_CLEAR_ERR)
1514 		clear_opt(sb, ERRORS_MASK);
1515 	if (token == Opt_noquota && sb_any_quota_loaded(sb)) {
1516 		ext4_msg(sb, KERN_ERR, "Cannot change quota "
1517 			 "options when quota turned on");
1518 		return -1;
1519 	}
1520 
1521 	if (m->flags & MOPT_NOSUPPORT) {
1522 		ext4_msg(sb, KERN_ERR, "%s option not supported", opt);
1523 	} else if (token == Opt_commit) {
1524 		if (arg == 0)
1525 			arg = JBD2_DEFAULT_MAX_COMMIT_AGE;
1526 		sbi->s_commit_interval = HZ * arg;
1527 	} else if (token == Opt_max_batch_time) {
1528 		if (arg == 0)
1529 			arg = EXT4_DEF_MAX_BATCH_TIME;
1530 		sbi->s_max_batch_time = arg;
1531 	} else if (token == Opt_min_batch_time) {
1532 		sbi->s_min_batch_time = arg;
1533 	} else if (token == Opt_inode_readahead_blks) {
1534 		if (arg && (arg > (1 << 30) || !is_power_of_2(arg))) {
1535 			ext4_msg(sb, KERN_ERR,
1536 				 "EXT4-fs: inode_readahead_blks must be "
1537 				 "0 or a power of 2 smaller than 2^31");
1538 			return -1;
1539 		}
1540 		sbi->s_inode_readahead_blks = arg;
1541 	} else if (token == Opt_init_itable) {
1542 		set_opt(sb, INIT_INODE_TABLE);
1543 		if (!args->from)
1544 			arg = EXT4_DEF_LI_WAIT_MULT;
1545 		sbi->s_li_wait_mult = arg;
1546 	} else if (token == Opt_max_dir_size_kb) {
1547 		sbi->s_max_dir_size_kb = arg;
1548 	} else if (token == Opt_stripe) {
1549 		sbi->s_stripe = arg;
1550 	} else if (token == Opt_resuid) {
1551 		uid = make_kuid(current_user_ns(), arg);
1552 		if (!uid_valid(uid)) {
1553 			ext4_msg(sb, KERN_ERR, "Invalid uid value %d", arg);
1554 			return -1;
1555 		}
1556 		sbi->s_resuid = uid;
1557 	} else if (token == Opt_resgid) {
1558 		gid = make_kgid(current_user_ns(), arg);
1559 		if (!gid_valid(gid)) {
1560 			ext4_msg(sb, KERN_ERR, "Invalid gid value %d", arg);
1561 			return -1;
1562 		}
1563 		sbi->s_resgid = gid;
1564 	} else if (token == Opt_journal_dev) {
1565 		if (is_remount) {
1566 			ext4_msg(sb, KERN_ERR,
1567 				 "Cannot specify journal on remount");
1568 			return -1;
1569 		}
1570 		*journal_devnum = arg;
1571 	} else if (token == Opt_journal_path) {
1572 		char *journal_path;
1573 		struct inode *journal_inode;
1574 		struct path path;
1575 		int error;
1576 
1577 		if (is_remount) {
1578 			ext4_msg(sb, KERN_ERR,
1579 				 "Cannot specify journal on remount");
1580 			return -1;
1581 		}
1582 		journal_path = match_strdup(&args[0]);
1583 		if (!journal_path) {
1584 			ext4_msg(sb, KERN_ERR, "error: could not dup "
1585 				"journal device string");
1586 			return -1;
1587 		}
1588 
1589 		error = kern_path(journal_path, LOOKUP_FOLLOW, &path);
1590 		if (error) {
1591 			ext4_msg(sb, KERN_ERR, "error: could not find "
1592 				"journal device path: error %d", error);
1593 			kfree(journal_path);
1594 			return -1;
1595 		}
1596 
1597 		journal_inode = path.dentry->d_inode;
1598 		if (!S_ISBLK(journal_inode->i_mode)) {
1599 			ext4_msg(sb, KERN_ERR, "error: journal path %s "
1600 				"is not a block device", journal_path);
1601 			path_put(&path);
1602 			kfree(journal_path);
1603 			return -1;
1604 		}
1605 
1606 		*journal_devnum = new_encode_dev(journal_inode->i_rdev);
1607 		path_put(&path);
1608 		kfree(journal_path);
1609 	} else if (token == Opt_journal_ioprio) {
1610 		if (arg > 7) {
1611 			ext4_msg(sb, KERN_ERR, "Invalid journal IO priority"
1612 				 " (must be 0-7)");
1613 			return -1;
1614 		}
1615 		*journal_ioprio =
1616 			IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, arg);
1617 	} else if (m->flags & MOPT_DATAJ) {
1618 		if (is_remount) {
1619 			if (!sbi->s_journal)
1620 				ext4_msg(sb, KERN_WARNING, "Remounting file system with no journal so ignoring journalled data option");
1621 			else if (test_opt(sb, DATA_FLAGS) != m->mount_opt) {
1622 				ext4_msg(sb, KERN_ERR,
1623 					 "Cannot change data mode on remount");
1624 				return -1;
1625 			}
1626 		} else {
1627 			clear_opt(sb, DATA_FLAGS);
1628 			sbi->s_mount_opt |= m->mount_opt;
1629 		}
1630 #ifdef CONFIG_QUOTA
1631 	} else if (m->flags & MOPT_QFMT) {
1632 		if (sb_any_quota_loaded(sb) &&
1633 		    sbi->s_jquota_fmt != m->mount_opt) {
1634 			ext4_msg(sb, KERN_ERR, "Cannot change journaled "
1635 				 "quota options when quota turned on");
1636 			return -1;
1637 		}
1638 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
1639 					       EXT4_FEATURE_RO_COMPAT_QUOTA)) {
1640 			ext4_msg(sb, KERN_ERR,
1641 				 "Cannot set journaled quota options "
1642 				 "when QUOTA feature is enabled");
1643 			return -1;
1644 		}
1645 		sbi->s_jquota_fmt = m->mount_opt;
1646 #endif
1647 	} else {
1648 		if (!args->from)
1649 			arg = 1;
1650 		if (m->flags & MOPT_CLEAR)
1651 			arg = !arg;
1652 		else if (unlikely(!(m->flags & MOPT_SET))) {
1653 			ext4_msg(sb, KERN_WARNING,
1654 				 "buggy handling of option %s", opt);
1655 			WARN_ON(1);
1656 			return -1;
1657 		}
1658 		if (arg != 0)
1659 			sbi->s_mount_opt |= m->mount_opt;
1660 		else
1661 			sbi->s_mount_opt &= ~m->mount_opt;
1662 	}
1663 	return 1;
1664 }
1665 
1666 static int parse_options(char *options, struct super_block *sb,
1667 			 unsigned long *journal_devnum,
1668 			 unsigned int *journal_ioprio,
1669 			 int is_remount)
1670 {
1671 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1672 	char *p;
1673 	substring_t args[MAX_OPT_ARGS];
1674 	int token;
1675 
1676 	if (!options)
1677 		return 1;
1678 
1679 	while ((p = strsep(&options, ",")) != NULL) {
1680 		if (!*p)
1681 			continue;
1682 		/*
1683 		 * Initialize args struct so we know whether arg was
1684 		 * found; some options take optional arguments.
1685 		 */
1686 		args[0].to = args[0].from = NULL;
1687 		token = match_token(p, tokens, args);
1688 		if (handle_mount_opt(sb, p, token, args, journal_devnum,
1689 				     journal_ioprio, is_remount) < 0)
1690 			return 0;
1691 	}
1692 #ifdef CONFIG_QUOTA
1693 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA) &&
1694 	    (test_opt(sb, USRQUOTA) || test_opt(sb, GRPQUOTA))) {
1695 		ext4_msg(sb, KERN_ERR, "Cannot set quota options when QUOTA "
1696 			 "feature is enabled");
1697 		return 0;
1698 	}
1699 	if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
1700 		if (test_opt(sb, USRQUOTA) && sbi->s_qf_names[USRQUOTA])
1701 			clear_opt(sb, USRQUOTA);
1702 
1703 		if (test_opt(sb, GRPQUOTA) && sbi->s_qf_names[GRPQUOTA])
1704 			clear_opt(sb, GRPQUOTA);
1705 
1706 		if (test_opt(sb, GRPQUOTA) || test_opt(sb, USRQUOTA)) {
1707 			ext4_msg(sb, KERN_ERR, "old and new quota "
1708 					"format mixing");
1709 			return 0;
1710 		}
1711 
1712 		if (!sbi->s_jquota_fmt) {
1713 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1714 					"not specified");
1715 			return 0;
1716 		}
1717 	} else {
1718 		if (sbi->s_jquota_fmt) {
1719 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1720 					"specified with no journaling "
1721 					"enabled");
1722 			return 0;
1723 		}
1724 	}
1725 #endif
1726 	if (test_opt(sb, DIOREAD_NOLOCK)) {
1727 		int blocksize =
1728 			BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
1729 
1730 		if (blocksize < PAGE_CACHE_SIZE) {
1731 			ext4_msg(sb, KERN_ERR, "can't mount with "
1732 				 "dioread_nolock if block size != PAGE_SIZE");
1733 			return 0;
1734 		}
1735 	}
1736 	return 1;
1737 }
1738 
1739 static inline void ext4_show_quota_options(struct seq_file *seq,
1740 					   struct super_block *sb)
1741 {
1742 #if defined(CONFIG_QUOTA)
1743 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1744 
1745 	if (sbi->s_jquota_fmt) {
1746 		char *fmtname = "";
1747 
1748 		switch (sbi->s_jquota_fmt) {
1749 		case QFMT_VFS_OLD:
1750 			fmtname = "vfsold";
1751 			break;
1752 		case QFMT_VFS_V0:
1753 			fmtname = "vfsv0";
1754 			break;
1755 		case QFMT_VFS_V1:
1756 			fmtname = "vfsv1";
1757 			break;
1758 		}
1759 		seq_printf(seq, ",jqfmt=%s", fmtname);
1760 	}
1761 
1762 	if (sbi->s_qf_names[USRQUOTA])
1763 		seq_printf(seq, ",usrjquota=%s", sbi->s_qf_names[USRQUOTA]);
1764 
1765 	if (sbi->s_qf_names[GRPQUOTA])
1766 		seq_printf(seq, ",grpjquota=%s", sbi->s_qf_names[GRPQUOTA]);
1767 #endif
1768 }
1769 
1770 static const char *token2str(int token)
1771 {
1772 	const struct match_token *t;
1773 
1774 	for (t = tokens; t->token != Opt_err; t++)
1775 		if (t->token == token && !strchr(t->pattern, '='))
1776 			break;
1777 	return t->pattern;
1778 }
1779 
1780 /*
1781  * Show an option if
1782  *  - it's set to a non-default value OR
1783  *  - if the per-sb default is different from the global default
1784  */
1785 static int _ext4_show_options(struct seq_file *seq, struct super_block *sb,
1786 			      int nodefs)
1787 {
1788 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1789 	struct ext4_super_block *es = sbi->s_es;
1790 	int def_errors, def_mount_opt = nodefs ? 0 : sbi->s_def_mount_opt;
1791 	const struct mount_opts *m;
1792 	char sep = nodefs ? '\n' : ',';
1793 
1794 #define SEQ_OPTS_PUTS(str) seq_printf(seq, "%c" str, sep)
1795 #define SEQ_OPTS_PRINT(str, arg) seq_printf(seq, "%c" str, sep, arg)
1796 
1797 	if (sbi->s_sb_block != 1)
1798 		SEQ_OPTS_PRINT("sb=%llu", sbi->s_sb_block);
1799 
1800 	for (m = ext4_mount_opts; m->token != Opt_err; m++) {
1801 		int want_set = m->flags & MOPT_SET;
1802 		if (((m->flags & (MOPT_SET|MOPT_CLEAR)) == 0) ||
1803 		    (m->flags & MOPT_CLEAR_ERR))
1804 			continue;
1805 		if (!(m->mount_opt & (sbi->s_mount_opt ^ def_mount_opt)))
1806 			continue; /* skip if same as the default */
1807 		if ((want_set &&
1808 		     (sbi->s_mount_opt & m->mount_opt) != m->mount_opt) ||
1809 		    (!want_set && (sbi->s_mount_opt & m->mount_opt)))
1810 			continue; /* select Opt_noFoo vs Opt_Foo */
1811 		SEQ_OPTS_PRINT("%s", token2str(m->token));
1812 	}
1813 
1814 	if (nodefs || !uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT4_DEF_RESUID)) ||
1815 	    le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID)
1816 		SEQ_OPTS_PRINT("resuid=%u",
1817 				from_kuid_munged(&init_user_ns, sbi->s_resuid));
1818 	if (nodefs || !gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT4_DEF_RESGID)) ||
1819 	    le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID)
1820 		SEQ_OPTS_PRINT("resgid=%u",
1821 				from_kgid_munged(&init_user_ns, sbi->s_resgid));
1822 	def_errors = nodefs ? -1 : le16_to_cpu(es->s_errors);
1823 	if (test_opt(sb, ERRORS_RO) && def_errors != EXT4_ERRORS_RO)
1824 		SEQ_OPTS_PUTS("errors=remount-ro");
1825 	if (test_opt(sb, ERRORS_CONT) && def_errors != EXT4_ERRORS_CONTINUE)
1826 		SEQ_OPTS_PUTS("errors=continue");
1827 	if (test_opt(sb, ERRORS_PANIC) && def_errors != EXT4_ERRORS_PANIC)
1828 		SEQ_OPTS_PUTS("errors=panic");
1829 	if (nodefs || sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ)
1830 		SEQ_OPTS_PRINT("commit=%lu", sbi->s_commit_interval / HZ);
1831 	if (nodefs || sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME)
1832 		SEQ_OPTS_PRINT("min_batch_time=%u", sbi->s_min_batch_time);
1833 	if (nodefs || sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME)
1834 		SEQ_OPTS_PRINT("max_batch_time=%u", sbi->s_max_batch_time);
1835 	if (sb->s_flags & MS_I_VERSION)
1836 		SEQ_OPTS_PUTS("i_version");
1837 	if (nodefs || sbi->s_stripe)
1838 		SEQ_OPTS_PRINT("stripe=%lu", sbi->s_stripe);
1839 	if (EXT4_MOUNT_DATA_FLAGS & (sbi->s_mount_opt ^ def_mount_opt)) {
1840 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
1841 			SEQ_OPTS_PUTS("data=journal");
1842 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
1843 			SEQ_OPTS_PUTS("data=ordered");
1844 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
1845 			SEQ_OPTS_PUTS("data=writeback");
1846 	}
1847 	if (nodefs ||
1848 	    sbi->s_inode_readahead_blks != EXT4_DEF_INODE_READAHEAD_BLKS)
1849 		SEQ_OPTS_PRINT("inode_readahead_blks=%u",
1850 			       sbi->s_inode_readahead_blks);
1851 
1852 	if (nodefs || (test_opt(sb, INIT_INODE_TABLE) &&
1853 		       (sbi->s_li_wait_mult != EXT4_DEF_LI_WAIT_MULT)))
1854 		SEQ_OPTS_PRINT("init_itable=%u", sbi->s_li_wait_mult);
1855 	if (nodefs || sbi->s_max_dir_size_kb)
1856 		SEQ_OPTS_PRINT("max_dir_size_kb=%u", sbi->s_max_dir_size_kb);
1857 
1858 	ext4_show_quota_options(seq, sb);
1859 	return 0;
1860 }
1861 
1862 static int ext4_show_options(struct seq_file *seq, struct dentry *root)
1863 {
1864 	return _ext4_show_options(seq, root->d_sb, 0);
1865 }
1866 
1867 static int options_seq_show(struct seq_file *seq, void *offset)
1868 {
1869 	struct super_block *sb = seq->private;
1870 	int rc;
1871 
1872 	seq_puts(seq, (sb->s_flags & MS_RDONLY) ? "ro" : "rw");
1873 	rc = _ext4_show_options(seq, sb, 1);
1874 	seq_puts(seq, "\n");
1875 	return rc;
1876 }
1877 
1878 static int options_open_fs(struct inode *inode, struct file *file)
1879 {
1880 	return single_open(file, options_seq_show, PDE_DATA(inode));
1881 }
1882 
1883 static const struct file_operations ext4_seq_options_fops = {
1884 	.owner = THIS_MODULE,
1885 	.open = options_open_fs,
1886 	.read = seq_read,
1887 	.llseek = seq_lseek,
1888 	.release = single_release,
1889 };
1890 
1891 static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
1892 			    int read_only)
1893 {
1894 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1895 	int res = 0;
1896 
1897 	if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
1898 		ext4_msg(sb, KERN_ERR, "revision level too high, "
1899 			 "forcing read-only mode");
1900 		res = MS_RDONLY;
1901 	}
1902 	if (read_only)
1903 		goto done;
1904 	if (!(sbi->s_mount_state & EXT4_VALID_FS))
1905 		ext4_msg(sb, KERN_WARNING, "warning: mounting unchecked fs, "
1906 			 "running e2fsck is recommended");
1907 	else if (sbi->s_mount_state & EXT4_ERROR_FS)
1908 		ext4_msg(sb, KERN_WARNING,
1909 			 "warning: mounting fs with errors, "
1910 			 "running e2fsck is recommended");
1911 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) > 0 &&
1912 		 le16_to_cpu(es->s_mnt_count) >=
1913 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
1914 		ext4_msg(sb, KERN_WARNING,
1915 			 "warning: maximal mount count reached, "
1916 			 "running e2fsck is recommended");
1917 	else if (le32_to_cpu(es->s_checkinterval) &&
1918 		(le32_to_cpu(es->s_lastcheck) +
1919 			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
1920 		ext4_msg(sb, KERN_WARNING,
1921 			 "warning: checktime reached, "
1922 			 "running e2fsck is recommended");
1923 	if (!sbi->s_journal)
1924 		es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1925 	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
1926 		es->s_max_mnt_count = cpu_to_le16(EXT4_DFL_MAX_MNT_COUNT);
1927 	le16_add_cpu(&es->s_mnt_count, 1);
1928 	es->s_mtime = cpu_to_le32(get_seconds());
1929 	ext4_update_dynamic_rev(sb);
1930 	if (sbi->s_journal)
1931 		EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
1932 
1933 	ext4_commit_super(sb, 1);
1934 done:
1935 	if (test_opt(sb, DEBUG))
1936 		printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, "
1937 				"bpg=%lu, ipg=%lu, mo=%04x, mo2=%04x]\n",
1938 			sb->s_blocksize,
1939 			sbi->s_groups_count,
1940 			EXT4_BLOCKS_PER_GROUP(sb),
1941 			EXT4_INODES_PER_GROUP(sb),
1942 			sbi->s_mount_opt, sbi->s_mount_opt2);
1943 
1944 	cleancache_init_fs(sb);
1945 	return res;
1946 }
1947 
1948 int ext4_alloc_flex_bg_array(struct super_block *sb, ext4_group_t ngroup)
1949 {
1950 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1951 	struct flex_groups *new_groups;
1952 	int size;
1953 
1954 	if (!sbi->s_log_groups_per_flex)
1955 		return 0;
1956 
1957 	size = ext4_flex_group(sbi, ngroup - 1) + 1;
1958 	if (size <= sbi->s_flex_groups_allocated)
1959 		return 0;
1960 
1961 	size = roundup_pow_of_two(size * sizeof(struct flex_groups));
1962 	new_groups = ext4_kvzalloc(size, GFP_KERNEL);
1963 	if (!new_groups) {
1964 		ext4_msg(sb, KERN_ERR, "not enough memory for %d flex groups",
1965 			 size / (int) sizeof(struct flex_groups));
1966 		return -ENOMEM;
1967 	}
1968 
1969 	if (sbi->s_flex_groups) {
1970 		memcpy(new_groups, sbi->s_flex_groups,
1971 		       (sbi->s_flex_groups_allocated *
1972 			sizeof(struct flex_groups)));
1973 		ext4_kvfree(sbi->s_flex_groups);
1974 	}
1975 	sbi->s_flex_groups = new_groups;
1976 	sbi->s_flex_groups_allocated = size / sizeof(struct flex_groups);
1977 	return 0;
1978 }
1979 
1980 static int ext4_fill_flex_info(struct super_block *sb)
1981 {
1982 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1983 	struct ext4_group_desc *gdp = NULL;
1984 	ext4_group_t flex_group;
1985 	int i, err;
1986 
1987 	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
1988 	if (sbi->s_log_groups_per_flex < 1 || sbi->s_log_groups_per_flex > 31) {
1989 		sbi->s_log_groups_per_flex = 0;
1990 		return 1;
1991 	}
1992 
1993 	err = ext4_alloc_flex_bg_array(sb, sbi->s_groups_count);
1994 	if (err)
1995 		goto failed;
1996 
1997 	for (i = 0; i < sbi->s_groups_count; i++) {
1998 		gdp = ext4_get_group_desc(sb, i, NULL);
1999 
2000 		flex_group = ext4_flex_group(sbi, i);
2001 		atomic_add(ext4_free_inodes_count(sb, gdp),
2002 			   &sbi->s_flex_groups[flex_group].free_inodes);
2003 		atomic64_add(ext4_free_group_clusters(sb, gdp),
2004 			     &sbi->s_flex_groups[flex_group].free_clusters);
2005 		atomic_add(ext4_used_dirs_count(sb, gdp),
2006 			   &sbi->s_flex_groups[flex_group].used_dirs);
2007 	}
2008 
2009 	return 1;
2010 failed:
2011 	return 0;
2012 }
2013 
2014 static __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
2015 				   struct ext4_group_desc *gdp)
2016 {
2017 	int offset;
2018 	__u16 crc = 0;
2019 	__le32 le_group = cpu_to_le32(block_group);
2020 
2021 	if ((sbi->s_es->s_feature_ro_compat &
2022 	     cpu_to_le32(EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))) {
2023 		/* Use new metadata_csum algorithm */
2024 		__le16 save_csum;
2025 		__u32 csum32;
2026 
2027 		save_csum = gdp->bg_checksum;
2028 		gdp->bg_checksum = 0;
2029 		csum32 = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&le_group,
2030 				     sizeof(le_group));
2031 		csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp,
2032 				     sbi->s_desc_size);
2033 		gdp->bg_checksum = save_csum;
2034 
2035 		crc = csum32 & 0xFFFF;
2036 		goto out;
2037 	}
2038 
2039 	/* old crc16 code */
2040 	offset = offsetof(struct ext4_group_desc, bg_checksum);
2041 
2042 	crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
2043 	crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
2044 	crc = crc16(crc, (__u8 *)gdp, offset);
2045 	offset += sizeof(gdp->bg_checksum); /* skip checksum */
2046 	/* for checksum of struct ext4_group_desc do the rest...*/
2047 	if ((sbi->s_es->s_feature_incompat &
2048 	     cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) &&
2049 	    offset < le16_to_cpu(sbi->s_es->s_desc_size))
2050 		crc = crc16(crc, (__u8 *)gdp + offset,
2051 			    le16_to_cpu(sbi->s_es->s_desc_size) -
2052 				offset);
2053 
2054 out:
2055 	return cpu_to_le16(crc);
2056 }
2057 
2058 int ext4_group_desc_csum_verify(struct super_block *sb, __u32 block_group,
2059 				struct ext4_group_desc *gdp)
2060 {
2061 	if (ext4_has_group_desc_csum(sb) &&
2062 	    (gdp->bg_checksum != ext4_group_desc_csum(EXT4_SB(sb),
2063 						      block_group, gdp)))
2064 		return 0;
2065 
2066 	return 1;
2067 }
2068 
2069 void ext4_group_desc_csum_set(struct super_block *sb, __u32 block_group,
2070 			      struct ext4_group_desc *gdp)
2071 {
2072 	if (!ext4_has_group_desc_csum(sb))
2073 		return;
2074 	gdp->bg_checksum = ext4_group_desc_csum(EXT4_SB(sb), block_group, gdp);
2075 }
2076 
2077 /* Called at mount-time, super-block is locked */
2078 static int ext4_check_descriptors(struct super_block *sb,
2079 				  ext4_group_t *first_not_zeroed)
2080 {
2081 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2082 	ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
2083 	ext4_fsblk_t last_block;
2084 	ext4_fsblk_t block_bitmap;
2085 	ext4_fsblk_t inode_bitmap;
2086 	ext4_fsblk_t inode_table;
2087 	int flexbg_flag = 0;
2088 	ext4_group_t i, grp = sbi->s_groups_count;
2089 
2090 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
2091 		flexbg_flag = 1;
2092 
2093 	ext4_debug("Checking group descriptors");
2094 
2095 	for (i = 0; i < sbi->s_groups_count; i++) {
2096 		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
2097 
2098 		if (i == sbi->s_groups_count - 1 || flexbg_flag)
2099 			last_block = ext4_blocks_count(sbi->s_es) - 1;
2100 		else
2101 			last_block = first_block +
2102 				(EXT4_BLOCKS_PER_GROUP(sb) - 1);
2103 
2104 		if ((grp == sbi->s_groups_count) &&
2105 		   !(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2106 			grp = i;
2107 
2108 		block_bitmap = ext4_block_bitmap(sb, gdp);
2109 		if (block_bitmap < first_block || block_bitmap > last_block) {
2110 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2111 			       "Block bitmap for group %u not in group "
2112 			       "(block %llu)!", i, block_bitmap);
2113 			return 0;
2114 		}
2115 		inode_bitmap = ext4_inode_bitmap(sb, gdp);
2116 		if (inode_bitmap < first_block || inode_bitmap > last_block) {
2117 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2118 			       "Inode bitmap for group %u not in group "
2119 			       "(block %llu)!", i, inode_bitmap);
2120 			return 0;
2121 		}
2122 		inode_table = ext4_inode_table(sb, gdp);
2123 		if (inode_table < first_block ||
2124 		    inode_table + sbi->s_itb_per_group - 1 > last_block) {
2125 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2126 			       "Inode table for group %u not in group "
2127 			       "(block %llu)!", i, inode_table);
2128 			return 0;
2129 		}
2130 		ext4_lock_group(sb, i);
2131 		if (!ext4_group_desc_csum_verify(sb, i, gdp)) {
2132 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2133 				 "Checksum for group %u failed (%u!=%u)",
2134 				 i, le16_to_cpu(ext4_group_desc_csum(sbi, i,
2135 				     gdp)), le16_to_cpu(gdp->bg_checksum));
2136 			if (!(sb->s_flags & MS_RDONLY)) {
2137 				ext4_unlock_group(sb, i);
2138 				return 0;
2139 			}
2140 		}
2141 		ext4_unlock_group(sb, i);
2142 		if (!flexbg_flag)
2143 			first_block += EXT4_BLOCKS_PER_GROUP(sb);
2144 	}
2145 	if (NULL != first_not_zeroed)
2146 		*first_not_zeroed = grp;
2147 
2148 	ext4_free_blocks_count_set(sbi->s_es,
2149 				   EXT4_C2B(sbi, ext4_count_free_clusters(sb)));
2150 	sbi->s_es->s_free_inodes_count =cpu_to_le32(ext4_count_free_inodes(sb));
2151 	return 1;
2152 }
2153 
2154 /* ext4_orphan_cleanup() walks a singly-linked list of inodes (starting at
2155  * the superblock) which were deleted from all directories, but held open by
2156  * a process at the time of a crash.  We walk the list and try to delete these
2157  * inodes at recovery time (only with a read-write filesystem).
2158  *
2159  * In order to keep the orphan inode chain consistent during traversal (in
2160  * case of crash during recovery), we link each inode into the superblock
2161  * orphan list_head and handle it the same way as an inode deletion during
2162  * normal operation (which journals the operations for us).
2163  *
2164  * We only do an iget() and an iput() on each inode, which is very safe if we
2165  * accidentally point at an in-use or already deleted inode.  The worst that
2166  * can happen in this case is that we get a "bit already cleared" message from
2167  * ext4_free_inode().  The only reason we would point at a wrong inode is if
2168  * e2fsck was run on this filesystem, and it must have already done the orphan
2169  * inode cleanup for us, so we can safely abort without any further action.
2170  */
2171 static void ext4_orphan_cleanup(struct super_block *sb,
2172 				struct ext4_super_block *es)
2173 {
2174 	unsigned int s_flags = sb->s_flags;
2175 	int nr_orphans = 0, nr_truncates = 0;
2176 #ifdef CONFIG_QUOTA
2177 	int i;
2178 #endif
2179 	if (!es->s_last_orphan) {
2180 		jbd_debug(4, "no orphan inodes to clean up\n");
2181 		return;
2182 	}
2183 
2184 	if (bdev_read_only(sb->s_bdev)) {
2185 		ext4_msg(sb, KERN_ERR, "write access "
2186 			"unavailable, skipping orphan cleanup");
2187 		return;
2188 	}
2189 
2190 	/* Check if feature set would not allow a r/w mount */
2191 	if (!ext4_feature_set_ok(sb, 0)) {
2192 		ext4_msg(sb, KERN_INFO, "Skipping orphan cleanup due to "
2193 			 "unknown ROCOMPAT features");
2194 		return;
2195 	}
2196 
2197 	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
2198 		/* don't clear list on RO mount w/ errors */
2199 		if (es->s_last_orphan && !(s_flags & MS_RDONLY)) {
2200 			jbd_debug(1, "Errors on filesystem, "
2201 				  "clearing orphan list.\n");
2202 			es->s_last_orphan = 0;
2203 		}
2204 		jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
2205 		return;
2206 	}
2207 
2208 	if (s_flags & MS_RDONLY) {
2209 		ext4_msg(sb, KERN_INFO, "orphan cleanup on readonly fs");
2210 		sb->s_flags &= ~MS_RDONLY;
2211 	}
2212 #ifdef CONFIG_QUOTA
2213 	/* Needed for iput() to work correctly and not trash data */
2214 	sb->s_flags |= MS_ACTIVE;
2215 	/* Turn on quotas so that they are updated correctly */
2216 	for (i = 0; i < MAXQUOTAS; i++) {
2217 		if (EXT4_SB(sb)->s_qf_names[i]) {
2218 			int ret = ext4_quota_on_mount(sb, i);
2219 			if (ret < 0)
2220 				ext4_msg(sb, KERN_ERR,
2221 					"Cannot turn on journaled "
2222 					"quota: error %d", ret);
2223 		}
2224 	}
2225 #endif
2226 
2227 	while (es->s_last_orphan) {
2228 		struct inode *inode;
2229 
2230 		inode = ext4_orphan_get(sb, le32_to_cpu(es->s_last_orphan));
2231 		if (IS_ERR(inode)) {
2232 			es->s_last_orphan = 0;
2233 			break;
2234 		}
2235 
2236 		list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
2237 		dquot_initialize(inode);
2238 		if (inode->i_nlink) {
2239 			if (test_opt(sb, DEBUG))
2240 				ext4_msg(sb, KERN_DEBUG,
2241 					"%s: truncating inode %lu to %lld bytes",
2242 					__func__, inode->i_ino, inode->i_size);
2243 			jbd_debug(2, "truncating inode %lu to %lld bytes\n",
2244 				  inode->i_ino, inode->i_size);
2245 			mutex_lock(&inode->i_mutex);
2246 			truncate_inode_pages(inode->i_mapping, inode->i_size);
2247 			ext4_truncate(inode);
2248 			mutex_unlock(&inode->i_mutex);
2249 			nr_truncates++;
2250 		} else {
2251 			if (test_opt(sb, DEBUG))
2252 				ext4_msg(sb, KERN_DEBUG,
2253 					"%s: deleting unreferenced inode %lu",
2254 					__func__, inode->i_ino);
2255 			jbd_debug(2, "deleting unreferenced inode %lu\n",
2256 				  inode->i_ino);
2257 			nr_orphans++;
2258 		}
2259 		iput(inode);  /* The delete magic happens here! */
2260 	}
2261 
2262 #define PLURAL(x) (x), ((x) == 1) ? "" : "s"
2263 
2264 	if (nr_orphans)
2265 		ext4_msg(sb, KERN_INFO, "%d orphan inode%s deleted",
2266 		       PLURAL(nr_orphans));
2267 	if (nr_truncates)
2268 		ext4_msg(sb, KERN_INFO, "%d truncate%s cleaned up",
2269 		       PLURAL(nr_truncates));
2270 #ifdef CONFIG_QUOTA
2271 	/* Turn quotas off */
2272 	for (i = 0; i < MAXQUOTAS; i++) {
2273 		if (sb_dqopt(sb)->files[i])
2274 			dquot_quota_off(sb, i);
2275 	}
2276 #endif
2277 	sb->s_flags = s_flags; /* Restore MS_RDONLY status */
2278 }
2279 
2280 /*
2281  * Maximal extent format file size.
2282  * Resulting logical blkno at s_maxbytes must fit in our on-disk
2283  * extent format containers, within a sector_t, and within i_blocks
2284  * in the vfs.  ext4 inode has 48 bits of i_block in fsblock units,
2285  * so that won't be a limiting factor.
2286  *
2287  * However there is other limiting factor. We do store extents in the form
2288  * of starting block and length, hence the resulting length of the extent
2289  * covering maximum file size must fit into on-disk format containers as
2290  * well. Given that length is always by 1 unit bigger than max unit (because
2291  * we count 0 as well) we have to lower the s_maxbytes by one fs block.
2292  *
2293  * Note, this does *not* consider any metadata overhead for vfs i_blocks.
2294  */
2295 static loff_t ext4_max_size(int blkbits, int has_huge_files)
2296 {
2297 	loff_t res;
2298 	loff_t upper_limit = MAX_LFS_FILESIZE;
2299 
2300 	/* small i_blocks in vfs inode? */
2301 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2302 		/*
2303 		 * CONFIG_LBDAF is not enabled implies the inode
2304 		 * i_block represent total blocks in 512 bytes
2305 		 * 32 == size of vfs inode i_blocks * 8
2306 		 */
2307 		upper_limit = (1LL << 32) - 1;
2308 
2309 		/* total blocks in file system block size */
2310 		upper_limit >>= (blkbits - 9);
2311 		upper_limit <<= blkbits;
2312 	}
2313 
2314 	/*
2315 	 * 32-bit extent-start container, ee_block. We lower the maxbytes
2316 	 * by one fs block, so ee_len can cover the extent of maximum file
2317 	 * size
2318 	 */
2319 	res = (1LL << 32) - 1;
2320 	res <<= blkbits;
2321 
2322 	/* Sanity check against vm- & vfs- imposed limits */
2323 	if (res > upper_limit)
2324 		res = upper_limit;
2325 
2326 	return res;
2327 }
2328 
2329 /*
2330  * Maximal bitmap file size.  There is a direct, and {,double-,triple-}indirect
2331  * block limit, and also a limit of (2^48 - 1) 512-byte sectors in i_blocks.
2332  * We need to be 1 filesystem block less than the 2^48 sector limit.
2333  */
2334 static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
2335 {
2336 	loff_t res = EXT4_NDIR_BLOCKS;
2337 	int meta_blocks;
2338 	loff_t upper_limit;
2339 	/* This is calculated to be the largest file size for a dense, block
2340 	 * mapped file such that the file's total number of 512-byte sectors,
2341 	 * including data and all indirect blocks, does not exceed (2^48 - 1).
2342 	 *
2343 	 * __u32 i_blocks_lo and _u16 i_blocks_high represent the total
2344 	 * number of 512-byte sectors of the file.
2345 	 */
2346 
2347 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2348 		/*
2349 		 * !has_huge_files or CONFIG_LBDAF not enabled implies that
2350 		 * the inode i_block field represents total file blocks in
2351 		 * 2^32 512-byte sectors == size of vfs inode i_blocks * 8
2352 		 */
2353 		upper_limit = (1LL << 32) - 1;
2354 
2355 		/* total blocks in file system block size */
2356 		upper_limit >>= (bits - 9);
2357 
2358 	} else {
2359 		/*
2360 		 * We use 48 bit ext4_inode i_blocks
2361 		 * With EXT4_HUGE_FILE_FL set the i_blocks
2362 		 * represent total number of blocks in
2363 		 * file system block size
2364 		 */
2365 		upper_limit = (1LL << 48) - 1;
2366 
2367 	}
2368 
2369 	/* indirect blocks */
2370 	meta_blocks = 1;
2371 	/* double indirect blocks */
2372 	meta_blocks += 1 + (1LL << (bits-2));
2373 	/* tripple indirect blocks */
2374 	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
2375 
2376 	upper_limit -= meta_blocks;
2377 	upper_limit <<= bits;
2378 
2379 	res += 1LL << (bits-2);
2380 	res += 1LL << (2*(bits-2));
2381 	res += 1LL << (3*(bits-2));
2382 	res <<= bits;
2383 	if (res > upper_limit)
2384 		res = upper_limit;
2385 
2386 	if (res > MAX_LFS_FILESIZE)
2387 		res = MAX_LFS_FILESIZE;
2388 
2389 	return res;
2390 }
2391 
2392 static ext4_fsblk_t descriptor_loc(struct super_block *sb,
2393 				   ext4_fsblk_t logical_sb_block, int nr)
2394 {
2395 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2396 	ext4_group_t bg, first_meta_bg;
2397 	int has_super = 0;
2398 
2399 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
2400 
2401 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
2402 	    nr < first_meta_bg)
2403 		return logical_sb_block + nr + 1;
2404 	bg = sbi->s_desc_per_block * nr;
2405 	if (ext4_bg_has_super(sb, bg))
2406 		has_super = 1;
2407 
2408 	/*
2409 	 * If we have a meta_bg fs with 1k blocks, group 0's GDT is at
2410 	 * block 2, not 1.  If s_first_data_block == 0 (bigalloc is enabled
2411 	 * on modern mke2fs or blksize > 1k on older mke2fs) then we must
2412 	 * compensate.
2413 	 */
2414 	if (sb->s_blocksize == 1024 && nr == 0 &&
2415 	    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block) == 0)
2416 		has_super++;
2417 
2418 	return (has_super + ext4_group_first_block_no(sb, bg));
2419 }
2420 
2421 /**
2422  * ext4_get_stripe_size: Get the stripe size.
2423  * @sbi: In memory super block info
2424  *
2425  * If we have specified it via mount option, then
2426  * use the mount option value. If the value specified at mount time is
2427  * greater than the blocks per group use the super block value.
2428  * If the super block value is greater than blocks per group return 0.
2429  * Allocator needs it be less than blocks per group.
2430  *
2431  */
2432 static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi)
2433 {
2434 	unsigned long stride = le16_to_cpu(sbi->s_es->s_raid_stride);
2435 	unsigned long stripe_width =
2436 			le32_to_cpu(sbi->s_es->s_raid_stripe_width);
2437 	int ret;
2438 
2439 	if (sbi->s_stripe && sbi->s_stripe <= sbi->s_blocks_per_group)
2440 		ret = sbi->s_stripe;
2441 	else if (stripe_width <= sbi->s_blocks_per_group)
2442 		ret = stripe_width;
2443 	else if (stride <= sbi->s_blocks_per_group)
2444 		ret = stride;
2445 	else
2446 		ret = 0;
2447 
2448 	/*
2449 	 * If the stripe width is 1, this makes no sense and
2450 	 * we set it to 0 to turn off stripe handling code.
2451 	 */
2452 	if (ret <= 1)
2453 		ret = 0;
2454 
2455 	return ret;
2456 }
2457 
2458 /* sysfs supprt */
2459 
2460 struct ext4_attr {
2461 	struct attribute attr;
2462 	ssize_t (*show)(struct ext4_attr *, struct ext4_sb_info *, char *);
2463 	ssize_t (*store)(struct ext4_attr *, struct ext4_sb_info *,
2464 			 const char *, size_t);
2465 	union {
2466 		int offset;
2467 		int deprecated_val;
2468 	} u;
2469 };
2470 
2471 static int parse_strtoull(const char *buf,
2472 		unsigned long long max, unsigned long long *value)
2473 {
2474 	int ret;
2475 
2476 	ret = kstrtoull(skip_spaces(buf), 0, value);
2477 	if (!ret && *value > max)
2478 		ret = -EINVAL;
2479 	return ret;
2480 }
2481 
2482 static ssize_t delayed_allocation_blocks_show(struct ext4_attr *a,
2483 					      struct ext4_sb_info *sbi,
2484 					      char *buf)
2485 {
2486 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2487 		(s64) EXT4_C2B(sbi,
2488 			percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
2489 }
2490 
2491 static ssize_t session_write_kbytes_show(struct ext4_attr *a,
2492 					 struct ext4_sb_info *sbi, char *buf)
2493 {
2494 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
2495 
2496 	if (!sb->s_bdev->bd_part)
2497 		return snprintf(buf, PAGE_SIZE, "0\n");
2498 	return snprintf(buf, PAGE_SIZE, "%lu\n",
2499 			(part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
2500 			 sbi->s_sectors_written_start) >> 1);
2501 }
2502 
2503 static ssize_t lifetime_write_kbytes_show(struct ext4_attr *a,
2504 					  struct ext4_sb_info *sbi, char *buf)
2505 {
2506 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
2507 
2508 	if (!sb->s_bdev->bd_part)
2509 		return snprintf(buf, PAGE_SIZE, "0\n");
2510 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2511 			(unsigned long long)(sbi->s_kbytes_written +
2512 			((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
2513 			  EXT4_SB(sb)->s_sectors_written_start) >> 1)));
2514 }
2515 
2516 static ssize_t inode_readahead_blks_store(struct ext4_attr *a,
2517 					  struct ext4_sb_info *sbi,
2518 					  const char *buf, size_t count)
2519 {
2520 	unsigned long t;
2521 	int ret;
2522 
2523 	ret = kstrtoul(skip_spaces(buf), 0, &t);
2524 	if (ret)
2525 		return ret;
2526 
2527 	if (t && (!is_power_of_2(t) || t > 0x40000000))
2528 		return -EINVAL;
2529 
2530 	sbi->s_inode_readahead_blks = t;
2531 	return count;
2532 }
2533 
2534 static ssize_t sbi_ui_show(struct ext4_attr *a,
2535 			   struct ext4_sb_info *sbi, char *buf)
2536 {
2537 	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->u.offset);
2538 
2539 	return snprintf(buf, PAGE_SIZE, "%u\n", *ui);
2540 }
2541 
2542 static ssize_t sbi_ui_store(struct ext4_attr *a,
2543 			    struct ext4_sb_info *sbi,
2544 			    const char *buf, size_t count)
2545 {
2546 	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->u.offset);
2547 	unsigned long t;
2548 	int ret;
2549 
2550 	ret = kstrtoul(skip_spaces(buf), 0, &t);
2551 	if (ret)
2552 		return ret;
2553 	*ui = t;
2554 	return count;
2555 }
2556 
2557 static ssize_t reserved_clusters_show(struct ext4_attr *a,
2558 				  struct ext4_sb_info *sbi, char *buf)
2559 {
2560 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2561 		(unsigned long long) atomic64_read(&sbi->s_resv_clusters));
2562 }
2563 
2564 static ssize_t reserved_clusters_store(struct ext4_attr *a,
2565 				   struct ext4_sb_info *sbi,
2566 				   const char *buf, size_t count)
2567 {
2568 	unsigned long long val;
2569 	int ret;
2570 
2571 	if (parse_strtoull(buf, -1ULL, &val))
2572 		return -EINVAL;
2573 	ret = ext4_reserve_clusters(sbi, val);
2574 
2575 	return ret ? ret : count;
2576 }
2577 
2578 static ssize_t trigger_test_error(struct ext4_attr *a,
2579 				  struct ext4_sb_info *sbi,
2580 				  const char *buf, size_t count)
2581 {
2582 	int len = count;
2583 
2584 	if (!capable(CAP_SYS_ADMIN))
2585 		return -EPERM;
2586 
2587 	if (len && buf[len-1] == '\n')
2588 		len--;
2589 
2590 	if (len)
2591 		ext4_error(sbi->s_sb, "%.*s", len, buf);
2592 	return count;
2593 }
2594 
2595 static ssize_t sbi_deprecated_show(struct ext4_attr *a,
2596 				   struct ext4_sb_info *sbi, char *buf)
2597 {
2598 	return snprintf(buf, PAGE_SIZE, "%d\n", a->u.deprecated_val);
2599 }
2600 
2601 #define EXT4_ATTR_OFFSET(_name,_mode,_show,_store,_elname) \
2602 static struct ext4_attr ext4_attr_##_name = {			\
2603 	.attr = {.name = __stringify(_name), .mode = _mode },	\
2604 	.show	= _show,					\
2605 	.store	= _store,					\
2606 	.u = {							\
2607 		.offset = offsetof(struct ext4_sb_info, _elname),\
2608 	},							\
2609 }
2610 #define EXT4_ATTR(name, mode, show, store) \
2611 static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store)
2612 
2613 #define EXT4_INFO_ATTR(name) EXT4_ATTR(name, 0444, NULL, NULL)
2614 #define EXT4_RO_ATTR(name) EXT4_ATTR(name, 0444, name##_show, NULL)
2615 #define EXT4_RW_ATTR(name) EXT4_ATTR(name, 0644, name##_show, name##_store)
2616 #define EXT4_RW_ATTR_SBI_UI(name, elname)	\
2617 	EXT4_ATTR_OFFSET(name, 0644, sbi_ui_show, sbi_ui_store, elname)
2618 #define ATTR_LIST(name) &ext4_attr_##name.attr
2619 #define EXT4_DEPRECATED_ATTR(_name, _val)	\
2620 static struct ext4_attr ext4_attr_##_name = {			\
2621 	.attr = {.name = __stringify(_name), .mode = 0444 },	\
2622 	.show	= sbi_deprecated_show,				\
2623 	.u = {							\
2624 		.deprecated_val = _val,				\
2625 	},							\
2626 }
2627 
2628 EXT4_RO_ATTR(delayed_allocation_blocks);
2629 EXT4_RO_ATTR(session_write_kbytes);
2630 EXT4_RO_ATTR(lifetime_write_kbytes);
2631 EXT4_RW_ATTR(reserved_clusters);
2632 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, sbi_ui_show,
2633 		 inode_readahead_blks_store, s_inode_readahead_blks);
2634 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
2635 EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
2636 EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
2637 EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
2638 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
2639 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
2640 EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
2641 EXT4_DEPRECATED_ATTR(max_writeback_mb_bump, 128);
2642 EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
2643 EXT4_ATTR(trigger_fs_error, 0200, NULL, trigger_test_error);
2644 EXT4_RW_ATTR_SBI_UI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
2645 EXT4_RW_ATTR_SBI_UI(err_ratelimit_burst, s_err_ratelimit_state.burst);
2646 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
2647 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
2648 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
2649 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
2650 
2651 static struct attribute *ext4_attrs[] = {
2652 	ATTR_LIST(delayed_allocation_blocks),
2653 	ATTR_LIST(session_write_kbytes),
2654 	ATTR_LIST(lifetime_write_kbytes),
2655 	ATTR_LIST(reserved_clusters),
2656 	ATTR_LIST(inode_readahead_blks),
2657 	ATTR_LIST(inode_goal),
2658 	ATTR_LIST(mb_stats),
2659 	ATTR_LIST(mb_max_to_scan),
2660 	ATTR_LIST(mb_min_to_scan),
2661 	ATTR_LIST(mb_order2_req),
2662 	ATTR_LIST(mb_stream_req),
2663 	ATTR_LIST(mb_group_prealloc),
2664 	ATTR_LIST(max_writeback_mb_bump),
2665 	ATTR_LIST(extent_max_zeroout_kb),
2666 	ATTR_LIST(trigger_fs_error),
2667 	ATTR_LIST(err_ratelimit_interval_ms),
2668 	ATTR_LIST(err_ratelimit_burst),
2669 	ATTR_LIST(warning_ratelimit_interval_ms),
2670 	ATTR_LIST(warning_ratelimit_burst),
2671 	ATTR_LIST(msg_ratelimit_interval_ms),
2672 	ATTR_LIST(msg_ratelimit_burst),
2673 	NULL,
2674 };
2675 
2676 /* Features this copy of ext4 supports */
2677 EXT4_INFO_ATTR(lazy_itable_init);
2678 EXT4_INFO_ATTR(batched_discard);
2679 EXT4_INFO_ATTR(meta_bg_resize);
2680 
2681 static struct attribute *ext4_feat_attrs[] = {
2682 	ATTR_LIST(lazy_itable_init),
2683 	ATTR_LIST(batched_discard),
2684 	ATTR_LIST(meta_bg_resize),
2685 	NULL,
2686 };
2687 
2688 static ssize_t ext4_attr_show(struct kobject *kobj,
2689 			      struct attribute *attr, char *buf)
2690 {
2691 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2692 						s_kobj);
2693 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
2694 
2695 	return a->show ? a->show(a, sbi, buf) : 0;
2696 }
2697 
2698 static ssize_t ext4_attr_store(struct kobject *kobj,
2699 			       struct attribute *attr,
2700 			       const char *buf, size_t len)
2701 {
2702 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2703 						s_kobj);
2704 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
2705 
2706 	return a->store ? a->store(a, sbi, buf, len) : 0;
2707 }
2708 
2709 static void ext4_sb_release(struct kobject *kobj)
2710 {
2711 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2712 						s_kobj);
2713 	complete(&sbi->s_kobj_unregister);
2714 }
2715 
2716 static const struct sysfs_ops ext4_attr_ops = {
2717 	.show	= ext4_attr_show,
2718 	.store	= ext4_attr_store,
2719 };
2720 
2721 static struct kobj_type ext4_ktype = {
2722 	.default_attrs	= ext4_attrs,
2723 	.sysfs_ops	= &ext4_attr_ops,
2724 	.release	= ext4_sb_release,
2725 };
2726 
2727 static void ext4_feat_release(struct kobject *kobj)
2728 {
2729 	complete(&ext4_feat->f_kobj_unregister);
2730 }
2731 
2732 static struct kobj_type ext4_feat_ktype = {
2733 	.default_attrs	= ext4_feat_attrs,
2734 	.sysfs_ops	= &ext4_attr_ops,
2735 	.release	= ext4_feat_release,
2736 };
2737 
2738 /*
2739  * Check whether this filesystem can be mounted based on
2740  * the features present and the RDONLY/RDWR mount requested.
2741  * Returns 1 if this filesystem can be mounted as requested,
2742  * 0 if it cannot be.
2743  */
2744 static int ext4_feature_set_ok(struct super_block *sb, int readonly)
2745 {
2746 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT4_FEATURE_INCOMPAT_SUPP)) {
2747 		ext4_msg(sb, KERN_ERR,
2748 			"Couldn't mount because of "
2749 			"unsupported optional features (%x)",
2750 			(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_incompat) &
2751 			~EXT4_FEATURE_INCOMPAT_SUPP));
2752 		return 0;
2753 	}
2754 
2755 	if (readonly)
2756 		return 1;
2757 
2758 	/* Check that feature set is OK for a read-write mount */
2759 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT4_FEATURE_RO_COMPAT_SUPP)) {
2760 		ext4_msg(sb, KERN_ERR, "couldn't mount RDWR because of "
2761 			 "unsupported optional features (%x)",
2762 			 (le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_ro_compat) &
2763 				~EXT4_FEATURE_RO_COMPAT_SUPP));
2764 		return 0;
2765 	}
2766 	/*
2767 	 * Large file size enabled file system can only be mounted
2768 	 * read-write on 32-bit systems if kernel is built with CONFIG_LBDAF
2769 	 */
2770 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
2771 		if (sizeof(blkcnt_t) < sizeof(u64)) {
2772 			ext4_msg(sb, KERN_ERR, "Filesystem with huge files "
2773 				 "cannot be mounted RDWR without "
2774 				 "CONFIG_LBDAF");
2775 			return 0;
2776 		}
2777 	}
2778 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_BIGALLOC) &&
2779 	    !EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
2780 		ext4_msg(sb, KERN_ERR,
2781 			 "Can't support bigalloc feature without "
2782 			 "extents feature\n");
2783 		return 0;
2784 	}
2785 
2786 #ifndef CONFIG_QUOTA
2787 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA) &&
2788 	    !readonly) {
2789 		ext4_msg(sb, KERN_ERR,
2790 			 "Filesystem with quota feature cannot be mounted RDWR "
2791 			 "without CONFIG_QUOTA");
2792 		return 0;
2793 	}
2794 #endif  /* CONFIG_QUOTA */
2795 	return 1;
2796 }
2797 
2798 /*
2799  * This function is called once a day if we have errors logged
2800  * on the file system
2801  */
2802 static void print_daily_error_info(unsigned long arg)
2803 {
2804 	struct super_block *sb = (struct super_block *) arg;
2805 	struct ext4_sb_info *sbi;
2806 	struct ext4_super_block *es;
2807 
2808 	sbi = EXT4_SB(sb);
2809 	es = sbi->s_es;
2810 
2811 	if (es->s_error_count)
2812 		ext4_msg(sb, KERN_NOTICE, "error count: %u",
2813 			 le32_to_cpu(es->s_error_count));
2814 	if (es->s_first_error_time) {
2815 		printk(KERN_NOTICE "EXT4-fs (%s): initial error at %u: %.*s:%d",
2816 		       sb->s_id, le32_to_cpu(es->s_first_error_time),
2817 		       (int) sizeof(es->s_first_error_func),
2818 		       es->s_first_error_func,
2819 		       le32_to_cpu(es->s_first_error_line));
2820 		if (es->s_first_error_ino)
2821 			printk(": inode %u",
2822 			       le32_to_cpu(es->s_first_error_ino));
2823 		if (es->s_first_error_block)
2824 			printk(": block %llu", (unsigned long long)
2825 			       le64_to_cpu(es->s_first_error_block));
2826 		printk("\n");
2827 	}
2828 	if (es->s_last_error_time) {
2829 		printk(KERN_NOTICE "EXT4-fs (%s): last error at %u: %.*s:%d",
2830 		       sb->s_id, le32_to_cpu(es->s_last_error_time),
2831 		       (int) sizeof(es->s_last_error_func),
2832 		       es->s_last_error_func,
2833 		       le32_to_cpu(es->s_last_error_line));
2834 		if (es->s_last_error_ino)
2835 			printk(": inode %u",
2836 			       le32_to_cpu(es->s_last_error_ino));
2837 		if (es->s_last_error_block)
2838 			printk(": block %llu", (unsigned long long)
2839 			       le64_to_cpu(es->s_last_error_block));
2840 		printk("\n");
2841 	}
2842 	mod_timer(&sbi->s_err_report, jiffies + 24*60*60*HZ);  /* Once a day */
2843 }
2844 
2845 /* Find next suitable group and run ext4_init_inode_table */
2846 static int ext4_run_li_request(struct ext4_li_request *elr)
2847 {
2848 	struct ext4_group_desc *gdp = NULL;
2849 	ext4_group_t group, ngroups;
2850 	struct super_block *sb;
2851 	unsigned long timeout = 0;
2852 	int ret = 0;
2853 
2854 	sb = elr->lr_super;
2855 	ngroups = EXT4_SB(sb)->s_groups_count;
2856 
2857 	sb_start_write(sb);
2858 	for (group = elr->lr_next_group; group < ngroups; group++) {
2859 		gdp = ext4_get_group_desc(sb, group, NULL);
2860 		if (!gdp) {
2861 			ret = 1;
2862 			break;
2863 		}
2864 
2865 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2866 			break;
2867 	}
2868 
2869 	if (group >= ngroups)
2870 		ret = 1;
2871 
2872 	if (!ret) {
2873 		timeout = jiffies;
2874 		ret = ext4_init_inode_table(sb, group,
2875 					    elr->lr_timeout ? 0 : 1);
2876 		if (elr->lr_timeout == 0) {
2877 			timeout = (jiffies - timeout) *
2878 				  elr->lr_sbi->s_li_wait_mult;
2879 			elr->lr_timeout = timeout;
2880 		}
2881 		elr->lr_next_sched = jiffies + elr->lr_timeout;
2882 		elr->lr_next_group = group + 1;
2883 	}
2884 	sb_end_write(sb);
2885 
2886 	return ret;
2887 }
2888 
2889 /*
2890  * Remove lr_request from the list_request and free the
2891  * request structure. Should be called with li_list_mtx held
2892  */
2893 static void ext4_remove_li_request(struct ext4_li_request *elr)
2894 {
2895 	struct ext4_sb_info *sbi;
2896 
2897 	if (!elr)
2898 		return;
2899 
2900 	sbi = elr->lr_sbi;
2901 
2902 	list_del(&elr->lr_request);
2903 	sbi->s_li_request = NULL;
2904 	kfree(elr);
2905 }
2906 
2907 static void ext4_unregister_li_request(struct super_block *sb)
2908 {
2909 	mutex_lock(&ext4_li_mtx);
2910 	if (!ext4_li_info) {
2911 		mutex_unlock(&ext4_li_mtx);
2912 		return;
2913 	}
2914 
2915 	mutex_lock(&ext4_li_info->li_list_mtx);
2916 	ext4_remove_li_request(EXT4_SB(sb)->s_li_request);
2917 	mutex_unlock(&ext4_li_info->li_list_mtx);
2918 	mutex_unlock(&ext4_li_mtx);
2919 }
2920 
2921 static struct task_struct *ext4_lazyinit_task;
2922 
2923 /*
2924  * This is the function where ext4lazyinit thread lives. It walks
2925  * through the request list searching for next scheduled filesystem.
2926  * When such a fs is found, run the lazy initialization request
2927  * (ext4_rn_li_request) and keep track of the time spend in this
2928  * function. Based on that time we compute next schedule time of
2929  * the request. When walking through the list is complete, compute
2930  * next waking time and put itself into sleep.
2931  */
2932 static int ext4_lazyinit_thread(void *arg)
2933 {
2934 	struct ext4_lazy_init *eli = (struct ext4_lazy_init *)arg;
2935 	struct list_head *pos, *n;
2936 	struct ext4_li_request *elr;
2937 	unsigned long next_wakeup, cur;
2938 
2939 	BUG_ON(NULL == eli);
2940 
2941 cont_thread:
2942 	while (true) {
2943 		next_wakeup = MAX_JIFFY_OFFSET;
2944 
2945 		mutex_lock(&eli->li_list_mtx);
2946 		if (list_empty(&eli->li_request_list)) {
2947 			mutex_unlock(&eli->li_list_mtx);
2948 			goto exit_thread;
2949 		}
2950 
2951 		list_for_each_safe(pos, n, &eli->li_request_list) {
2952 			elr = list_entry(pos, struct ext4_li_request,
2953 					 lr_request);
2954 
2955 			if (time_after_eq(jiffies, elr->lr_next_sched)) {
2956 				if (ext4_run_li_request(elr) != 0) {
2957 					/* error, remove the lazy_init job */
2958 					ext4_remove_li_request(elr);
2959 					continue;
2960 				}
2961 			}
2962 
2963 			if (time_before(elr->lr_next_sched, next_wakeup))
2964 				next_wakeup = elr->lr_next_sched;
2965 		}
2966 		mutex_unlock(&eli->li_list_mtx);
2967 
2968 		try_to_freeze();
2969 
2970 		cur = jiffies;
2971 		if ((time_after_eq(cur, next_wakeup)) ||
2972 		    (MAX_JIFFY_OFFSET == next_wakeup)) {
2973 			cond_resched();
2974 			continue;
2975 		}
2976 
2977 		schedule_timeout_interruptible(next_wakeup - cur);
2978 
2979 		if (kthread_should_stop()) {
2980 			ext4_clear_request_list();
2981 			goto exit_thread;
2982 		}
2983 	}
2984 
2985 exit_thread:
2986 	/*
2987 	 * It looks like the request list is empty, but we need
2988 	 * to check it under the li_list_mtx lock, to prevent any
2989 	 * additions into it, and of course we should lock ext4_li_mtx
2990 	 * to atomically free the list and ext4_li_info, because at
2991 	 * this point another ext4 filesystem could be registering
2992 	 * new one.
2993 	 */
2994 	mutex_lock(&ext4_li_mtx);
2995 	mutex_lock(&eli->li_list_mtx);
2996 	if (!list_empty(&eli->li_request_list)) {
2997 		mutex_unlock(&eli->li_list_mtx);
2998 		mutex_unlock(&ext4_li_mtx);
2999 		goto cont_thread;
3000 	}
3001 	mutex_unlock(&eli->li_list_mtx);
3002 	kfree(ext4_li_info);
3003 	ext4_li_info = NULL;
3004 	mutex_unlock(&ext4_li_mtx);
3005 
3006 	return 0;
3007 }
3008 
3009 static void ext4_clear_request_list(void)
3010 {
3011 	struct list_head *pos, *n;
3012 	struct ext4_li_request *elr;
3013 
3014 	mutex_lock(&ext4_li_info->li_list_mtx);
3015 	list_for_each_safe(pos, n, &ext4_li_info->li_request_list) {
3016 		elr = list_entry(pos, struct ext4_li_request,
3017 				 lr_request);
3018 		ext4_remove_li_request(elr);
3019 	}
3020 	mutex_unlock(&ext4_li_info->li_list_mtx);
3021 }
3022 
3023 static int ext4_run_lazyinit_thread(void)
3024 {
3025 	ext4_lazyinit_task = kthread_run(ext4_lazyinit_thread,
3026 					 ext4_li_info, "ext4lazyinit");
3027 	if (IS_ERR(ext4_lazyinit_task)) {
3028 		int err = PTR_ERR(ext4_lazyinit_task);
3029 		ext4_clear_request_list();
3030 		kfree(ext4_li_info);
3031 		ext4_li_info = NULL;
3032 		printk(KERN_CRIT "EXT4-fs: error %d creating inode table "
3033 				 "initialization thread\n",
3034 				 err);
3035 		return err;
3036 	}
3037 	ext4_li_info->li_state |= EXT4_LAZYINIT_RUNNING;
3038 	return 0;
3039 }
3040 
3041 /*
3042  * Check whether it make sense to run itable init. thread or not.
3043  * If there is at least one uninitialized inode table, return
3044  * corresponding group number, else the loop goes through all
3045  * groups and return total number of groups.
3046  */
3047 static ext4_group_t ext4_has_uninit_itable(struct super_block *sb)
3048 {
3049 	ext4_group_t group, ngroups = EXT4_SB(sb)->s_groups_count;
3050 	struct ext4_group_desc *gdp = NULL;
3051 
3052 	for (group = 0; group < ngroups; group++) {
3053 		gdp = ext4_get_group_desc(sb, group, NULL);
3054 		if (!gdp)
3055 			continue;
3056 
3057 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
3058 			break;
3059 	}
3060 
3061 	return group;
3062 }
3063 
3064 static int ext4_li_info_new(void)
3065 {
3066 	struct ext4_lazy_init *eli = NULL;
3067 
3068 	eli = kzalloc(sizeof(*eli), GFP_KERNEL);
3069 	if (!eli)
3070 		return -ENOMEM;
3071 
3072 	INIT_LIST_HEAD(&eli->li_request_list);
3073 	mutex_init(&eli->li_list_mtx);
3074 
3075 	eli->li_state |= EXT4_LAZYINIT_QUIT;
3076 
3077 	ext4_li_info = eli;
3078 
3079 	return 0;
3080 }
3081 
3082 static struct ext4_li_request *ext4_li_request_new(struct super_block *sb,
3083 					    ext4_group_t start)
3084 {
3085 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3086 	struct ext4_li_request *elr;
3087 
3088 	elr = kzalloc(sizeof(*elr), GFP_KERNEL);
3089 	if (!elr)
3090 		return NULL;
3091 
3092 	elr->lr_super = sb;
3093 	elr->lr_sbi = sbi;
3094 	elr->lr_next_group = start;
3095 
3096 	/*
3097 	 * Randomize first schedule time of the request to
3098 	 * spread the inode table initialization requests
3099 	 * better.
3100 	 */
3101 	elr->lr_next_sched = jiffies + (prandom_u32() %
3102 				(EXT4_DEF_LI_MAX_START_DELAY * HZ));
3103 	return elr;
3104 }
3105 
3106 int ext4_register_li_request(struct super_block *sb,
3107 			     ext4_group_t first_not_zeroed)
3108 {
3109 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3110 	struct ext4_li_request *elr = NULL;
3111 	ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
3112 	int ret = 0;
3113 
3114 	mutex_lock(&ext4_li_mtx);
3115 	if (sbi->s_li_request != NULL) {
3116 		/*
3117 		 * Reset timeout so it can be computed again, because
3118 		 * s_li_wait_mult might have changed.
3119 		 */
3120 		sbi->s_li_request->lr_timeout = 0;
3121 		goto out;
3122 	}
3123 
3124 	if (first_not_zeroed == ngroups ||
3125 	    (sb->s_flags & MS_RDONLY) ||
3126 	    !test_opt(sb, INIT_INODE_TABLE))
3127 		goto out;
3128 
3129 	elr = ext4_li_request_new(sb, first_not_zeroed);
3130 	if (!elr) {
3131 		ret = -ENOMEM;
3132 		goto out;
3133 	}
3134 
3135 	if (NULL == ext4_li_info) {
3136 		ret = ext4_li_info_new();
3137 		if (ret)
3138 			goto out;
3139 	}
3140 
3141 	mutex_lock(&ext4_li_info->li_list_mtx);
3142 	list_add(&elr->lr_request, &ext4_li_info->li_request_list);
3143 	mutex_unlock(&ext4_li_info->li_list_mtx);
3144 
3145 	sbi->s_li_request = elr;
3146 	/*
3147 	 * set elr to NULL here since it has been inserted to
3148 	 * the request_list and the removal and free of it is
3149 	 * handled by ext4_clear_request_list from now on.
3150 	 */
3151 	elr = NULL;
3152 
3153 	if (!(ext4_li_info->li_state & EXT4_LAZYINIT_RUNNING)) {
3154 		ret = ext4_run_lazyinit_thread();
3155 		if (ret)
3156 			goto out;
3157 	}
3158 out:
3159 	mutex_unlock(&ext4_li_mtx);
3160 	if (ret)
3161 		kfree(elr);
3162 	return ret;
3163 }
3164 
3165 /*
3166  * We do not need to lock anything since this is called on
3167  * module unload.
3168  */
3169 static void ext4_destroy_lazyinit_thread(void)
3170 {
3171 	/*
3172 	 * If thread exited earlier
3173 	 * there's nothing to be done.
3174 	 */
3175 	if (!ext4_li_info || !ext4_lazyinit_task)
3176 		return;
3177 
3178 	kthread_stop(ext4_lazyinit_task);
3179 }
3180 
3181 static int set_journal_csum_feature_set(struct super_block *sb)
3182 {
3183 	int ret = 1;
3184 	int compat, incompat;
3185 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3186 
3187 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3188 				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
3189 		/* journal checksum v2 */
3190 		compat = 0;
3191 		incompat = JBD2_FEATURE_INCOMPAT_CSUM_V2;
3192 	} else {
3193 		/* journal checksum v1 */
3194 		compat = JBD2_FEATURE_COMPAT_CHECKSUM;
3195 		incompat = 0;
3196 	}
3197 
3198 	if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
3199 		ret = jbd2_journal_set_features(sbi->s_journal,
3200 				compat, 0,
3201 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT |
3202 				incompat);
3203 	} else if (test_opt(sb, JOURNAL_CHECKSUM)) {
3204 		ret = jbd2_journal_set_features(sbi->s_journal,
3205 				compat, 0,
3206 				incompat);
3207 		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
3208 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
3209 	} else {
3210 		jbd2_journal_clear_features(sbi->s_journal,
3211 				JBD2_FEATURE_COMPAT_CHECKSUM, 0,
3212 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT |
3213 				JBD2_FEATURE_INCOMPAT_CSUM_V2);
3214 	}
3215 
3216 	return ret;
3217 }
3218 
3219 /*
3220  * Note: calculating the overhead so we can be compatible with
3221  * historical BSD practice is quite difficult in the face of
3222  * clusters/bigalloc.  This is because multiple metadata blocks from
3223  * different block group can end up in the same allocation cluster.
3224  * Calculating the exact overhead in the face of clustered allocation
3225  * requires either O(all block bitmaps) in memory or O(number of block
3226  * groups**2) in time.  We will still calculate the superblock for
3227  * older file systems --- and if we come across with a bigalloc file
3228  * system with zero in s_overhead_clusters the estimate will be close to
3229  * correct especially for very large cluster sizes --- but for newer
3230  * file systems, it's better to calculate this figure once at mkfs
3231  * time, and store it in the superblock.  If the superblock value is
3232  * present (even for non-bigalloc file systems), we will use it.
3233  */
3234 static int count_overhead(struct super_block *sb, ext4_group_t grp,
3235 			  char *buf)
3236 {
3237 	struct ext4_sb_info	*sbi = EXT4_SB(sb);
3238 	struct ext4_group_desc	*gdp;
3239 	ext4_fsblk_t		first_block, last_block, b;
3240 	ext4_group_t		i, ngroups = ext4_get_groups_count(sb);
3241 	int			s, j, count = 0;
3242 
3243 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_BIGALLOC))
3244 		return (ext4_bg_has_super(sb, grp) + ext4_bg_num_gdb(sb, grp) +
3245 			sbi->s_itb_per_group + 2);
3246 
3247 	first_block = le32_to_cpu(sbi->s_es->s_first_data_block) +
3248 		(grp * EXT4_BLOCKS_PER_GROUP(sb));
3249 	last_block = first_block + EXT4_BLOCKS_PER_GROUP(sb) - 1;
3250 	for (i = 0; i < ngroups; i++) {
3251 		gdp = ext4_get_group_desc(sb, i, NULL);
3252 		b = ext4_block_bitmap(sb, gdp);
3253 		if (b >= first_block && b <= last_block) {
3254 			ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf);
3255 			count++;
3256 		}
3257 		b = ext4_inode_bitmap(sb, gdp);
3258 		if (b >= first_block && b <= last_block) {
3259 			ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf);
3260 			count++;
3261 		}
3262 		b = ext4_inode_table(sb, gdp);
3263 		if (b >= first_block && b + sbi->s_itb_per_group <= last_block)
3264 			for (j = 0; j < sbi->s_itb_per_group; j++, b++) {
3265 				int c = EXT4_B2C(sbi, b - first_block);
3266 				ext4_set_bit(c, buf);
3267 				count++;
3268 			}
3269 		if (i != grp)
3270 			continue;
3271 		s = 0;
3272 		if (ext4_bg_has_super(sb, grp)) {
3273 			ext4_set_bit(s++, buf);
3274 			count++;
3275 		}
3276 		for (j = ext4_bg_num_gdb(sb, grp); j > 0; j--) {
3277 			ext4_set_bit(EXT4_B2C(sbi, s++), buf);
3278 			count++;
3279 		}
3280 	}
3281 	if (!count)
3282 		return 0;
3283 	return EXT4_CLUSTERS_PER_GROUP(sb) -
3284 		ext4_count_free(buf, EXT4_CLUSTERS_PER_GROUP(sb) / 8);
3285 }
3286 
3287 /*
3288  * Compute the overhead and stash it in sbi->s_overhead
3289  */
3290 int ext4_calculate_overhead(struct super_block *sb)
3291 {
3292 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3293 	struct ext4_super_block *es = sbi->s_es;
3294 	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
3295 	ext4_fsblk_t overhead = 0;
3296 	char *buf = (char *) get_zeroed_page(GFP_KERNEL);
3297 
3298 	if (!buf)
3299 		return -ENOMEM;
3300 
3301 	/*
3302 	 * Compute the overhead (FS structures).  This is constant
3303 	 * for a given filesystem unless the number of block groups
3304 	 * changes so we cache the previous value until it does.
3305 	 */
3306 
3307 	/*
3308 	 * All of the blocks before first_data_block are overhead
3309 	 */
3310 	overhead = EXT4_B2C(sbi, le32_to_cpu(es->s_first_data_block));
3311 
3312 	/*
3313 	 * Add the overhead found in each block group
3314 	 */
3315 	for (i = 0; i < ngroups; i++) {
3316 		int blks;
3317 
3318 		blks = count_overhead(sb, i, buf);
3319 		overhead += blks;
3320 		if (blks)
3321 			memset(buf, 0, PAGE_SIZE);
3322 		cond_resched();
3323 	}
3324 	/* Add the journal blocks as well */
3325 	if (sbi->s_journal)
3326 		overhead += EXT4_NUM_B2C(sbi, sbi->s_journal->j_maxlen);
3327 
3328 	sbi->s_overhead = overhead;
3329 	smp_wmb();
3330 	free_page((unsigned long) buf);
3331 	return 0;
3332 }
3333 
3334 
3335 static ext4_fsblk_t ext4_calculate_resv_clusters(struct super_block *sb)
3336 {
3337 	ext4_fsblk_t resv_clusters;
3338 
3339 	/*
3340 	 * There's no need to reserve anything when we aren't using extents.
3341 	 * The space estimates are exact, there are no unwritten extents,
3342 	 * hole punching doesn't need new metadata... This is needed especially
3343 	 * to keep ext2/3 backward compatibility.
3344 	 */
3345 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
3346 		return 0;
3347 	/*
3348 	 * By default we reserve 2% or 4096 clusters, whichever is smaller.
3349 	 * This should cover the situations where we can not afford to run
3350 	 * out of space like for example punch hole, or converting
3351 	 * unwritten extents in delalloc path. In most cases such
3352 	 * allocation would require 1, or 2 blocks, higher numbers are
3353 	 * very rare.
3354 	 */
3355 	resv_clusters = ext4_blocks_count(EXT4_SB(sb)->s_es) >>
3356 			EXT4_SB(sb)->s_cluster_bits;
3357 
3358 	do_div(resv_clusters, 50);
3359 	resv_clusters = min_t(ext4_fsblk_t, resv_clusters, 4096);
3360 
3361 	return resv_clusters;
3362 }
3363 
3364 
3365 static int ext4_reserve_clusters(struct ext4_sb_info *sbi, ext4_fsblk_t count)
3366 {
3367 	ext4_fsblk_t clusters = ext4_blocks_count(sbi->s_es) >>
3368 				sbi->s_cluster_bits;
3369 
3370 	if (count >= clusters)
3371 		return -EINVAL;
3372 
3373 	atomic64_set(&sbi->s_resv_clusters, count);
3374 	return 0;
3375 }
3376 
3377 static int ext4_fill_super(struct super_block *sb, void *data, int silent)
3378 {
3379 	char *orig_data = kstrdup(data, GFP_KERNEL);
3380 	struct buffer_head *bh;
3381 	struct ext4_super_block *es = NULL;
3382 	struct ext4_sb_info *sbi;
3383 	ext4_fsblk_t block;
3384 	ext4_fsblk_t sb_block = get_sb_block(&data);
3385 	ext4_fsblk_t logical_sb_block;
3386 	unsigned long offset = 0;
3387 	unsigned long journal_devnum = 0;
3388 	unsigned long def_mount_opts;
3389 	struct inode *root;
3390 	char *cp;
3391 	const char *descr;
3392 	int ret = -ENOMEM;
3393 	int blocksize, clustersize;
3394 	unsigned int db_count;
3395 	unsigned int i;
3396 	int needs_recovery, has_huge_files, has_bigalloc;
3397 	__u64 blocks_count;
3398 	int err = 0;
3399 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
3400 	ext4_group_t first_not_zeroed;
3401 
3402 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
3403 	if (!sbi)
3404 		goto out_free_orig;
3405 
3406 	sbi->s_blockgroup_lock =
3407 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
3408 	if (!sbi->s_blockgroup_lock) {
3409 		kfree(sbi);
3410 		goto out_free_orig;
3411 	}
3412 	sb->s_fs_info = sbi;
3413 	sbi->s_sb = sb;
3414 	sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
3415 	sbi->s_sb_block = sb_block;
3416 	if (sb->s_bdev->bd_part)
3417 		sbi->s_sectors_written_start =
3418 			part_stat_read(sb->s_bdev->bd_part, sectors[1]);
3419 
3420 	/* Cleanup superblock name */
3421 	for (cp = sb->s_id; (cp = strchr(cp, '/'));)
3422 		*cp = '!';
3423 
3424 	/* -EINVAL is default */
3425 	ret = -EINVAL;
3426 	blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
3427 	if (!blocksize) {
3428 		ext4_msg(sb, KERN_ERR, "unable to set blocksize");
3429 		goto out_fail;
3430 	}
3431 
3432 	/*
3433 	 * The ext4 superblock will not be buffer aligned for other than 1kB
3434 	 * block sizes.  We need to calculate the offset from buffer start.
3435 	 */
3436 	if (blocksize != EXT4_MIN_BLOCK_SIZE) {
3437 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3438 		offset = do_div(logical_sb_block, blocksize);
3439 	} else {
3440 		logical_sb_block = sb_block;
3441 	}
3442 
3443 	if (!(bh = sb_bread(sb, logical_sb_block))) {
3444 		ext4_msg(sb, KERN_ERR, "unable to read superblock");
3445 		goto out_fail;
3446 	}
3447 	/*
3448 	 * Note: s_es must be initialized as soon as possible because
3449 	 *       some ext4 macro-instructions depend on its value
3450 	 */
3451 	es = (struct ext4_super_block *) (bh->b_data + offset);
3452 	sbi->s_es = es;
3453 	sb->s_magic = le16_to_cpu(es->s_magic);
3454 	if (sb->s_magic != EXT4_SUPER_MAGIC)
3455 		goto cantfind_ext4;
3456 	sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
3457 
3458 	/* Warn if metadata_csum and gdt_csum are both set. */
3459 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3460 				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
3461 	    EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
3462 		ext4_warning(sb, KERN_INFO "metadata_csum and uninit_bg are "
3463 			     "redundant flags; please run fsck.");
3464 
3465 	/* Check for a known checksum algorithm */
3466 	if (!ext4_verify_csum_type(sb, es)) {
3467 		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
3468 			 "unknown checksum algorithm.");
3469 		silent = 1;
3470 		goto cantfind_ext4;
3471 	}
3472 
3473 	/* Load the checksum driver */
3474 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3475 				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
3476 		sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
3477 		if (IS_ERR(sbi->s_chksum_driver)) {
3478 			ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
3479 			ret = PTR_ERR(sbi->s_chksum_driver);
3480 			sbi->s_chksum_driver = NULL;
3481 			goto failed_mount;
3482 		}
3483 	}
3484 
3485 	/* Check superblock checksum */
3486 	if (!ext4_superblock_csum_verify(sb, es)) {
3487 		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
3488 			 "invalid superblock checksum.  Run e2fsck?");
3489 		silent = 1;
3490 		goto cantfind_ext4;
3491 	}
3492 
3493 	/* Precompute checksum seed for all metadata */
3494 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3495 			EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
3496 		sbi->s_csum_seed = ext4_chksum(sbi, ~0, es->s_uuid,
3497 					       sizeof(es->s_uuid));
3498 
3499 	/* Set defaults before we parse the mount options */
3500 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
3501 	set_opt(sb, INIT_INODE_TABLE);
3502 	if (def_mount_opts & EXT4_DEFM_DEBUG)
3503 		set_opt(sb, DEBUG);
3504 	if (def_mount_opts & EXT4_DEFM_BSDGROUPS)
3505 		set_opt(sb, GRPID);
3506 	if (def_mount_opts & EXT4_DEFM_UID16)
3507 		set_opt(sb, NO_UID32);
3508 	/* xattr user namespace & acls are now defaulted on */
3509 	set_opt(sb, XATTR_USER);
3510 #ifdef CONFIG_EXT4_FS_POSIX_ACL
3511 	set_opt(sb, POSIX_ACL);
3512 #endif
3513 	if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA)
3514 		set_opt(sb, JOURNAL_DATA);
3515 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_ORDERED)
3516 		set_opt(sb, ORDERED_DATA);
3517 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_WBACK)
3518 		set_opt(sb, WRITEBACK_DATA);
3519 
3520 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_PANIC)
3521 		set_opt(sb, ERRORS_PANIC);
3522 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_CONTINUE)
3523 		set_opt(sb, ERRORS_CONT);
3524 	else
3525 		set_opt(sb, ERRORS_RO);
3526 	if (def_mount_opts & EXT4_DEFM_BLOCK_VALIDITY)
3527 		set_opt(sb, BLOCK_VALIDITY);
3528 	if (def_mount_opts & EXT4_DEFM_DISCARD)
3529 		set_opt(sb, DISCARD);
3530 
3531 	sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
3532 	sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
3533 	sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ;
3534 	sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;
3535 	sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;
3536 
3537 	if ((def_mount_opts & EXT4_DEFM_NOBARRIER) == 0)
3538 		set_opt(sb, BARRIER);
3539 
3540 	/*
3541 	 * enable delayed allocation by default
3542 	 * Use -o nodelalloc to turn it off
3543 	 */
3544 	if (!IS_EXT3_SB(sb) && !IS_EXT2_SB(sb) &&
3545 	    ((def_mount_opts & EXT4_DEFM_NODELALLOC) == 0))
3546 		set_opt(sb, DELALLOC);
3547 
3548 	/*
3549 	 * set default s_li_wait_mult for lazyinit, for the case there is
3550 	 * no mount option specified.
3551 	 */
3552 	sbi->s_li_wait_mult = EXT4_DEF_LI_WAIT_MULT;
3553 
3554 	if (!parse_options((char *) sbi->s_es->s_mount_opts, sb,
3555 			   &journal_devnum, &journal_ioprio, 0)) {
3556 		ext4_msg(sb, KERN_WARNING,
3557 			 "failed to parse options in superblock: %s",
3558 			 sbi->s_es->s_mount_opts);
3559 	}
3560 	sbi->s_def_mount_opt = sbi->s_mount_opt;
3561 	if (!parse_options((char *) data, sb, &journal_devnum,
3562 			   &journal_ioprio, 0))
3563 		goto failed_mount;
3564 
3565 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
3566 		printk_once(KERN_WARNING "EXT4-fs: Warning: mounting "
3567 			    "with data=journal disables delayed "
3568 			    "allocation and O_DIRECT support!\n");
3569 		if (test_opt2(sb, EXPLICIT_DELALLOC)) {
3570 			ext4_msg(sb, KERN_ERR, "can't mount with "
3571 				 "both data=journal and delalloc");
3572 			goto failed_mount;
3573 		}
3574 		if (test_opt(sb, DIOREAD_NOLOCK)) {
3575 			ext4_msg(sb, KERN_ERR, "can't mount with "
3576 				 "both data=journal and dioread_nolock");
3577 			goto failed_mount;
3578 		}
3579 		if (test_opt(sb, DELALLOC))
3580 			clear_opt(sb, DELALLOC);
3581 	}
3582 
3583 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
3584 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
3585 
3586 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
3587 	    (EXT4_HAS_COMPAT_FEATURE(sb, ~0U) ||
3588 	     EXT4_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
3589 	     EXT4_HAS_INCOMPAT_FEATURE(sb, ~0U)))
3590 		ext4_msg(sb, KERN_WARNING,
3591 		       "feature flags set on rev 0 fs, "
3592 		       "running e2fsck is recommended");
3593 
3594 	if (es->s_creator_os == cpu_to_le32(EXT4_OS_HURD)) {
3595 		set_opt2(sb, HURD_COMPAT);
3596 		if (EXT4_HAS_INCOMPAT_FEATURE(sb,
3597 					      EXT4_FEATURE_INCOMPAT_64BIT)) {
3598 			ext4_msg(sb, KERN_ERR,
3599 				 "The Hurd can't support 64-bit file systems");
3600 			goto failed_mount;
3601 		}
3602 	}
3603 
3604 	if (IS_EXT2_SB(sb)) {
3605 		if (ext2_feature_set_ok(sb))
3606 			ext4_msg(sb, KERN_INFO, "mounting ext2 file system "
3607 				 "using the ext4 subsystem");
3608 		else {
3609 			ext4_msg(sb, KERN_ERR, "couldn't mount as ext2 due "
3610 				 "to feature incompatibilities");
3611 			goto failed_mount;
3612 		}
3613 	}
3614 
3615 	if (IS_EXT3_SB(sb)) {
3616 		if (ext3_feature_set_ok(sb))
3617 			ext4_msg(sb, KERN_INFO, "mounting ext3 file system "
3618 				 "using the ext4 subsystem");
3619 		else {
3620 			ext4_msg(sb, KERN_ERR, "couldn't mount as ext3 due "
3621 				 "to feature incompatibilities");
3622 			goto failed_mount;
3623 		}
3624 	}
3625 
3626 	/*
3627 	 * Check feature flags regardless of the revision level, since we
3628 	 * previously didn't change the revision level when setting the flags,
3629 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
3630 	 */
3631 	if (!ext4_feature_set_ok(sb, (sb->s_flags & MS_RDONLY)))
3632 		goto failed_mount;
3633 
3634 	blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
3635 	if (blocksize < EXT4_MIN_BLOCK_SIZE ||
3636 	    blocksize > EXT4_MAX_BLOCK_SIZE) {
3637 		ext4_msg(sb, KERN_ERR,
3638 		       "Unsupported filesystem blocksize %d", blocksize);
3639 		goto failed_mount;
3640 	}
3641 
3642 	if (sb->s_blocksize != blocksize) {
3643 		/* Validate the filesystem blocksize */
3644 		if (!sb_set_blocksize(sb, blocksize)) {
3645 			ext4_msg(sb, KERN_ERR, "bad block size %d",
3646 					blocksize);
3647 			goto failed_mount;
3648 		}
3649 
3650 		brelse(bh);
3651 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3652 		offset = do_div(logical_sb_block, blocksize);
3653 		bh = sb_bread(sb, logical_sb_block);
3654 		if (!bh) {
3655 			ext4_msg(sb, KERN_ERR,
3656 			       "Can't read superblock on 2nd try");
3657 			goto failed_mount;
3658 		}
3659 		es = (struct ext4_super_block *)(bh->b_data + offset);
3660 		sbi->s_es = es;
3661 		if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
3662 			ext4_msg(sb, KERN_ERR,
3663 			       "Magic mismatch, very weird!");
3664 			goto failed_mount;
3665 		}
3666 	}
3667 
3668 	has_huge_files = EXT4_HAS_RO_COMPAT_FEATURE(sb,
3669 				EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
3670 	sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits,
3671 						      has_huge_files);
3672 	sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits, has_huge_files);
3673 
3674 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) {
3675 		sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE;
3676 		sbi->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
3677 	} else {
3678 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
3679 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
3680 		if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
3681 		    (!is_power_of_2(sbi->s_inode_size)) ||
3682 		    (sbi->s_inode_size > blocksize)) {
3683 			ext4_msg(sb, KERN_ERR,
3684 			       "unsupported inode size: %d",
3685 			       sbi->s_inode_size);
3686 			goto failed_mount;
3687 		}
3688 		if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE)
3689 			sb->s_time_gran = 1 << (EXT4_EPOCH_BITS - 2);
3690 	}
3691 
3692 	sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
3693 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT)) {
3694 		if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT ||
3695 		    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
3696 		    !is_power_of_2(sbi->s_desc_size)) {
3697 			ext4_msg(sb, KERN_ERR,
3698 			       "unsupported descriptor size %lu",
3699 			       sbi->s_desc_size);
3700 			goto failed_mount;
3701 		}
3702 	} else
3703 		sbi->s_desc_size = EXT4_MIN_DESC_SIZE;
3704 
3705 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
3706 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
3707 	if (EXT4_INODE_SIZE(sb) == 0 || EXT4_INODES_PER_GROUP(sb) == 0)
3708 		goto cantfind_ext4;
3709 
3710 	sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
3711 	if (sbi->s_inodes_per_block == 0)
3712 		goto cantfind_ext4;
3713 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
3714 					sbi->s_inodes_per_block;
3715 	sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
3716 	sbi->s_sbh = bh;
3717 	sbi->s_mount_state = le16_to_cpu(es->s_state);
3718 	sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
3719 	sbi->s_desc_per_block_bits = ilog2(EXT4_DESC_PER_BLOCK(sb));
3720 
3721 	for (i = 0; i < 4; i++)
3722 		sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
3723 	sbi->s_def_hash_version = es->s_def_hash_version;
3724 	if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_DIR_INDEX)) {
3725 		i = le32_to_cpu(es->s_flags);
3726 		if (i & EXT2_FLAGS_UNSIGNED_HASH)
3727 			sbi->s_hash_unsigned = 3;
3728 		else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) {
3729 #ifdef __CHAR_UNSIGNED__
3730 			if (!(sb->s_flags & MS_RDONLY))
3731 				es->s_flags |=
3732 					cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH);
3733 			sbi->s_hash_unsigned = 3;
3734 #else
3735 			if (!(sb->s_flags & MS_RDONLY))
3736 				es->s_flags |=
3737 					cpu_to_le32(EXT2_FLAGS_SIGNED_HASH);
3738 #endif
3739 		}
3740 	}
3741 
3742 	/* Handle clustersize */
3743 	clustersize = BLOCK_SIZE << le32_to_cpu(es->s_log_cluster_size);
3744 	has_bigalloc = EXT4_HAS_RO_COMPAT_FEATURE(sb,
3745 				EXT4_FEATURE_RO_COMPAT_BIGALLOC);
3746 	if (has_bigalloc) {
3747 		if (clustersize < blocksize) {
3748 			ext4_msg(sb, KERN_ERR,
3749 				 "cluster size (%d) smaller than "
3750 				 "block size (%d)", clustersize, blocksize);
3751 			goto failed_mount;
3752 		}
3753 		sbi->s_cluster_bits = le32_to_cpu(es->s_log_cluster_size) -
3754 			le32_to_cpu(es->s_log_block_size);
3755 		sbi->s_clusters_per_group =
3756 			le32_to_cpu(es->s_clusters_per_group);
3757 		if (sbi->s_clusters_per_group > blocksize * 8) {
3758 			ext4_msg(sb, KERN_ERR,
3759 				 "#clusters per group too big: %lu",
3760 				 sbi->s_clusters_per_group);
3761 			goto failed_mount;
3762 		}
3763 		if (sbi->s_blocks_per_group !=
3764 		    (sbi->s_clusters_per_group * (clustersize / blocksize))) {
3765 			ext4_msg(sb, KERN_ERR, "blocks per group (%lu) and "
3766 				 "clusters per group (%lu) inconsistent",
3767 				 sbi->s_blocks_per_group,
3768 				 sbi->s_clusters_per_group);
3769 			goto failed_mount;
3770 		}
3771 	} else {
3772 		if (clustersize != blocksize) {
3773 			ext4_warning(sb, "fragment/cluster size (%d) != "
3774 				     "block size (%d)", clustersize,
3775 				     blocksize);
3776 			clustersize = blocksize;
3777 		}
3778 		if (sbi->s_blocks_per_group > blocksize * 8) {
3779 			ext4_msg(sb, KERN_ERR,
3780 				 "#blocks per group too big: %lu",
3781 				 sbi->s_blocks_per_group);
3782 			goto failed_mount;
3783 		}
3784 		sbi->s_clusters_per_group = sbi->s_blocks_per_group;
3785 		sbi->s_cluster_bits = 0;
3786 	}
3787 	sbi->s_cluster_ratio = clustersize / blocksize;
3788 
3789 	if (sbi->s_inodes_per_group > blocksize * 8) {
3790 		ext4_msg(sb, KERN_ERR,
3791 		       "#inodes per group too big: %lu",
3792 		       sbi->s_inodes_per_group);
3793 		goto failed_mount;
3794 	}
3795 
3796 	/* Do we have standard group size of clustersize * 8 blocks ? */
3797 	if (sbi->s_blocks_per_group == clustersize << 3)
3798 		set_opt2(sb, STD_GROUP_SIZE);
3799 
3800 	/*
3801 	 * Test whether we have more sectors than will fit in sector_t,
3802 	 * and whether the max offset is addressable by the page cache.
3803 	 */
3804 	err = generic_check_addressable(sb->s_blocksize_bits,
3805 					ext4_blocks_count(es));
3806 	if (err) {
3807 		ext4_msg(sb, KERN_ERR, "filesystem"
3808 			 " too large to mount safely on this system");
3809 		if (sizeof(sector_t) < 8)
3810 			ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled");
3811 		goto failed_mount;
3812 	}
3813 
3814 	if (EXT4_BLOCKS_PER_GROUP(sb) == 0)
3815 		goto cantfind_ext4;
3816 
3817 	/* check blocks count against device size */
3818 	blocks_count = sb->s_bdev->bd_inode->i_size >> sb->s_blocksize_bits;
3819 	if (blocks_count && ext4_blocks_count(es) > blocks_count) {
3820 		ext4_msg(sb, KERN_WARNING, "bad geometry: block count %llu "
3821 		       "exceeds size of device (%llu blocks)",
3822 		       ext4_blocks_count(es), blocks_count);
3823 		goto failed_mount;
3824 	}
3825 
3826 	/*
3827 	 * It makes no sense for the first data block to be beyond the end
3828 	 * of the filesystem.
3829 	 */
3830 	if (le32_to_cpu(es->s_first_data_block) >= ext4_blocks_count(es)) {
3831 		ext4_msg(sb, KERN_WARNING, "bad geometry: first data "
3832 			 "block %u is beyond end of filesystem (%llu)",
3833 			 le32_to_cpu(es->s_first_data_block),
3834 			 ext4_blocks_count(es));
3835 		goto failed_mount;
3836 	}
3837 	blocks_count = (ext4_blocks_count(es) -
3838 			le32_to_cpu(es->s_first_data_block) +
3839 			EXT4_BLOCKS_PER_GROUP(sb) - 1);
3840 	do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
3841 	if (blocks_count > ((uint64_t)1<<32) - EXT4_DESC_PER_BLOCK(sb)) {
3842 		ext4_msg(sb, KERN_WARNING, "groups count too large: %u "
3843 		       "(block count %llu, first data block %u, "
3844 		       "blocks per group %lu)", sbi->s_groups_count,
3845 		       ext4_blocks_count(es),
3846 		       le32_to_cpu(es->s_first_data_block),
3847 		       EXT4_BLOCKS_PER_GROUP(sb));
3848 		goto failed_mount;
3849 	}
3850 	sbi->s_groups_count = blocks_count;
3851 	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
3852 			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
3853 	db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
3854 		   EXT4_DESC_PER_BLOCK(sb);
3855 	sbi->s_group_desc = ext4_kvmalloc(db_count *
3856 					  sizeof(struct buffer_head *),
3857 					  GFP_KERNEL);
3858 	if (sbi->s_group_desc == NULL) {
3859 		ext4_msg(sb, KERN_ERR, "not enough memory");
3860 		ret = -ENOMEM;
3861 		goto failed_mount;
3862 	}
3863 
3864 	if (ext4_proc_root)
3865 		sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
3866 
3867 	if (sbi->s_proc)
3868 		proc_create_data("options", S_IRUGO, sbi->s_proc,
3869 				 &ext4_seq_options_fops, sb);
3870 
3871 	bgl_lock_init(sbi->s_blockgroup_lock);
3872 
3873 	for (i = 0; i < db_count; i++) {
3874 		block = descriptor_loc(sb, logical_sb_block, i);
3875 		sbi->s_group_desc[i] = sb_bread(sb, block);
3876 		if (!sbi->s_group_desc[i]) {
3877 			ext4_msg(sb, KERN_ERR,
3878 			       "can't read group descriptor %d", i);
3879 			db_count = i;
3880 			goto failed_mount2;
3881 		}
3882 	}
3883 
3884 	/*
3885 	 * set up enough so that it can read an inode,
3886 	 * and create new inode for buddy allocator
3887 	 */
3888 	sbi->s_gdb_count = db_count;
3889 	if (!test_opt(sb, NOLOAD) &&
3890 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL))
3891 		sb->s_op = &ext4_sops;
3892 	else
3893 		sb->s_op = &ext4_nojournal_sops;
3894 
3895 	ext4_ext_init(sb);
3896 	err = ext4_mb_init(sb);
3897 	if (err) {
3898 		ext4_msg(sb, KERN_ERR, "failed to initialize mballoc (%d)",
3899 			 err);
3900 		goto failed_mount2;
3901 	}
3902 
3903 	if (!ext4_check_descriptors(sb, &first_not_zeroed)) {
3904 		ext4_msg(sb, KERN_ERR, "group descriptors corrupted!");
3905 		goto failed_mount2a;
3906 	}
3907 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
3908 		if (!ext4_fill_flex_info(sb)) {
3909 			ext4_msg(sb, KERN_ERR,
3910 			       "unable to initialize "
3911 			       "flex_bg meta info!");
3912 			goto failed_mount2a;
3913 		}
3914 
3915 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
3916 	spin_lock_init(&sbi->s_next_gen_lock);
3917 
3918 	init_timer(&sbi->s_err_report);
3919 	sbi->s_err_report.function = print_daily_error_info;
3920 	sbi->s_err_report.data = (unsigned long) sb;
3921 
3922 	/* Register extent status tree shrinker */
3923 	ext4_es_register_shrinker(sbi);
3924 
3925 	err = percpu_counter_init(&sbi->s_freeclusters_counter,
3926 			ext4_count_free_clusters(sb));
3927 	if (!err) {
3928 		err = percpu_counter_init(&sbi->s_freeinodes_counter,
3929 				ext4_count_free_inodes(sb));
3930 	}
3931 	if (!err) {
3932 		err = percpu_counter_init(&sbi->s_dirs_counter,
3933 				ext4_count_dirs(sb));
3934 	}
3935 	if (!err) {
3936 		err = percpu_counter_init(&sbi->s_dirtyclusters_counter, 0);
3937 	}
3938 	if (!err) {
3939 		err = percpu_counter_init(&sbi->s_extent_cache_cnt, 0);
3940 	}
3941 	if (err) {
3942 		ext4_msg(sb, KERN_ERR, "insufficient memory");
3943 		goto failed_mount3;
3944 	}
3945 
3946 	sbi->s_stripe = ext4_get_stripe_size(sbi);
3947 	sbi->s_extent_max_zeroout_kb = 32;
3948 
3949 	sb->s_export_op = &ext4_export_ops;
3950 	sb->s_xattr = ext4_xattr_handlers;
3951 #ifdef CONFIG_QUOTA
3952 	sb->dq_op = &ext4_quota_operations;
3953 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA))
3954 		sb->s_qcop = &ext4_qctl_sysfile_operations;
3955 	else
3956 		sb->s_qcop = &ext4_qctl_operations;
3957 #endif
3958 	memcpy(sb->s_uuid, es->s_uuid, sizeof(es->s_uuid));
3959 
3960 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
3961 	mutex_init(&sbi->s_orphan_lock);
3962 
3963 	sb->s_root = NULL;
3964 
3965 	needs_recovery = (es->s_last_orphan != 0 ||
3966 			  EXT4_HAS_INCOMPAT_FEATURE(sb,
3967 				    EXT4_FEATURE_INCOMPAT_RECOVER));
3968 
3969 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_MMP) &&
3970 	    !(sb->s_flags & MS_RDONLY))
3971 		if (ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block)))
3972 			goto failed_mount3;
3973 
3974 	/*
3975 	 * The first inode we look at is the journal inode.  Don't try
3976 	 * root first: it may be modified in the journal!
3977 	 */
3978 	if (!test_opt(sb, NOLOAD) &&
3979 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
3980 		if (ext4_load_journal(sb, es, journal_devnum))
3981 			goto failed_mount3;
3982 	} else if (test_opt(sb, NOLOAD) && !(sb->s_flags & MS_RDONLY) &&
3983 	      EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
3984 		ext4_msg(sb, KERN_ERR, "required journal recovery "
3985 		       "suppressed and not mounted read-only");
3986 		goto failed_mount_wq;
3987 	} else {
3988 		clear_opt(sb, DATA_FLAGS);
3989 		sbi->s_journal = NULL;
3990 		needs_recovery = 0;
3991 		goto no_journal;
3992 	}
3993 
3994 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT) &&
3995 	    !jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
3996 				       JBD2_FEATURE_INCOMPAT_64BIT)) {
3997 		ext4_msg(sb, KERN_ERR, "Failed to set 64-bit journal feature");
3998 		goto failed_mount_wq;
3999 	}
4000 
4001 	if (!set_journal_csum_feature_set(sb)) {
4002 		ext4_msg(sb, KERN_ERR, "Failed to set journal checksum "
4003 			 "feature set");
4004 		goto failed_mount_wq;
4005 	}
4006 
4007 	/* We have now updated the journal if required, so we can
4008 	 * validate the data journaling mode. */
4009 	switch (test_opt(sb, DATA_FLAGS)) {
4010 	case 0:
4011 		/* No mode set, assume a default based on the journal
4012 		 * capabilities: ORDERED_DATA if the journal can
4013 		 * cope, else JOURNAL_DATA
4014 		 */
4015 		if (jbd2_journal_check_available_features
4016 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE))
4017 			set_opt(sb, ORDERED_DATA);
4018 		else
4019 			set_opt(sb, JOURNAL_DATA);
4020 		break;
4021 
4022 	case EXT4_MOUNT_ORDERED_DATA:
4023 	case EXT4_MOUNT_WRITEBACK_DATA:
4024 		if (!jbd2_journal_check_available_features
4025 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
4026 			ext4_msg(sb, KERN_ERR, "Journal does not support "
4027 			       "requested data journaling mode");
4028 			goto failed_mount_wq;
4029 		}
4030 	default:
4031 		break;
4032 	}
4033 	set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
4034 
4035 	sbi->s_journal->j_commit_callback = ext4_journal_commit_callback;
4036 
4037 	/*
4038 	 * The journal may have updated the bg summary counts, so we
4039 	 * need to update the global counters.
4040 	 */
4041 	percpu_counter_set(&sbi->s_freeclusters_counter,
4042 			   ext4_count_free_clusters(sb));
4043 	percpu_counter_set(&sbi->s_freeinodes_counter,
4044 			   ext4_count_free_inodes(sb));
4045 	percpu_counter_set(&sbi->s_dirs_counter,
4046 			   ext4_count_dirs(sb));
4047 	percpu_counter_set(&sbi->s_dirtyclusters_counter, 0);
4048 
4049 no_journal:
4050 	if (ext4_mballoc_ready) {
4051 		sbi->s_mb_cache = ext4_xattr_create_cache(sb->s_id);
4052 		if (!sbi->s_mb_cache) {
4053 			ext4_msg(sb, KERN_ERR, "Failed to create an mb_cache");
4054 			goto failed_mount_wq;
4055 		}
4056 	}
4057 
4058 	/*
4059 	 * Get the # of file system overhead blocks from the
4060 	 * superblock if present.
4061 	 */
4062 	if (es->s_overhead_clusters)
4063 		sbi->s_overhead = le32_to_cpu(es->s_overhead_clusters);
4064 	else {
4065 		err = ext4_calculate_overhead(sb);
4066 		if (err)
4067 			goto failed_mount_wq;
4068 	}
4069 
4070 	/*
4071 	 * The maximum number of concurrent works can be high and
4072 	 * concurrency isn't really necessary.  Limit it to 1.
4073 	 */
4074 	EXT4_SB(sb)->rsv_conversion_wq =
4075 		alloc_workqueue("ext4-rsv-conversion", WQ_MEM_RECLAIM | WQ_UNBOUND, 1);
4076 	if (!EXT4_SB(sb)->rsv_conversion_wq) {
4077 		printk(KERN_ERR "EXT4-fs: failed to create workqueue\n");
4078 		ret = -ENOMEM;
4079 		goto failed_mount4;
4080 	}
4081 
4082 	/*
4083 	 * The jbd2_journal_load will have done any necessary log recovery,
4084 	 * so we can safely mount the rest of the filesystem now.
4085 	 */
4086 
4087 	root = ext4_iget(sb, EXT4_ROOT_INO);
4088 	if (IS_ERR(root)) {
4089 		ext4_msg(sb, KERN_ERR, "get root inode failed");
4090 		ret = PTR_ERR(root);
4091 		root = NULL;
4092 		goto failed_mount4;
4093 	}
4094 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
4095 		ext4_msg(sb, KERN_ERR, "corrupt root inode, run e2fsck");
4096 		iput(root);
4097 		goto failed_mount4;
4098 	}
4099 	sb->s_root = d_make_root(root);
4100 	if (!sb->s_root) {
4101 		ext4_msg(sb, KERN_ERR, "get root dentry failed");
4102 		ret = -ENOMEM;
4103 		goto failed_mount4;
4104 	}
4105 
4106 	if (ext4_setup_super(sb, es, sb->s_flags & MS_RDONLY))
4107 		sb->s_flags |= MS_RDONLY;
4108 
4109 	/* determine the minimum size of new large inodes, if present */
4110 	if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
4111 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
4112 						     EXT4_GOOD_OLD_INODE_SIZE;
4113 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
4114 				       EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE)) {
4115 			if (sbi->s_want_extra_isize <
4116 			    le16_to_cpu(es->s_want_extra_isize))
4117 				sbi->s_want_extra_isize =
4118 					le16_to_cpu(es->s_want_extra_isize);
4119 			if (sbi->s_want_extra_isize <
4120 			    le16_to_cpu(es->s_min_extra_isize))
4121 				sbi->s_want_extra_isize =
4122 					le16_to_cpu(es->s_min_extra_isize);
4123 		}
4124 	}
4125 	/* Check if enough inode space is available */
4126 	if (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize >
4127 							sbi->s_inode_size) {
4128 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
4129 						       EXT4_GOOD_OLD_INODE_SIZE;
4130 		ext4_msg(sb, KERN_INFO, "required extra inode space not"
4131 			 "available");
4132 	}
4133 
4134 	err = ext4_reserve_clusters(sbi, ext4_calculate_resv_clusters(sb));
4135 	if (err) {
4136 		ext4_msg(sb, KERN_ERR, "failed to reserve %llu clusters for "
4137 			 "reserved pool", ext4_calculate_resv_clusters(sb));
4138 		goto failed_mount5;
4139 	}
4140 
4141 	err = ext4_setup_system_zone(sb);
4142 	if (err) {
4143 		ext4_msg(sb, KERN_ERR, "failed to initialize system "
4144 			 "zone (%d)", err);
4145 		goto failed_mount5;
4146 	}
4147 
4148 	err = ext4_register_li_request(sb, first_not_zeroed);
4149 	if (err)
4150 		goto failed_mount6;
4151 
4152 	sbi->s_kobj.kset = ext4_kset;
4153 	init_completion(&sbi->s_kobj_unregister);
4154 	err = kobject_init_and_add(&sbi->s_kobj, &ext4_ktype, NULL,
4155 				   "%s", sb->s_id);
4156 	if (err)
4157 		goto failed_mount7;
4158 
4159 #ifdef CONFIG_QUOTA
4160 	/* Enable quota usage during mount. */
4161 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA) &&
4162 	    !(sb->s_flags & MS_RDONLY)) {
4163 		err = ext4_enable_quotas(sb);
4164 		if (err)
4165 			goto failed_mount8;
4166 	}
4167 #endif  /* CONFIG_QUOTA */
4168 
4169 	EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
4170 	ext4_orphan_cleanup(sb, es);
4171 	EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
4172 	if (needs_recovery) {
4173 		ext4_msg(sb, KERN_INFO, "recovery complete");
4174 		ext4_mark_recovery_complete(sb, es);
4175 	}
4176 	if (EXT4_SB(sb)->s_journal) {
4177 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
4178 			descr = " journalled data mode";
4179 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
4180 			descr = " ordered data mode";
4181 		else
4182 			descr = " writeback data mode";
4183 	} else
4184 		descr = "out journal";
4185 
4186 	if (test_opt(sb, DISCARD)) {
4187 		struct request_queue *q = bdev_get_queue(sb->s_bdev);
4188 		if (!blk_queue_discard(q))
4189 			ext4_msg(sb, KERN_WARNING,
4190 				 "mounting with \"discard\" option, but "
4191 				 "the device does not support discard");
4192 	}
4193 
4194 	ext4_msg(sb, KERN_INFO, "mounted filesystem with%s. "
4195 		 "Opts: %s%s%s", descr, sbi->s_es->s_mount_opts,
4196 		 *sbi->s_es->s_mount_opts ? "; " : "", orig_data);
4197 
4198 	if (es->s_error_count)
4199 		mod_timer(&sbi->s_err_report, jiffies + 300*HZ); /* 5 minutes */
4200 
4201 	/* Enable message ratelimiting. Default is 10 messages per 5 secs. */
4202 	ratelimit_state_init(&sbi->s_err_ratelimit_state, 5 * HZ, 10);
4203 	ratelimit_state_init(&sbi->s_warning_ratelimit_state, 5 * HZ, 10);
4204 	ratelimit_state_init(&sbi->s_msg_ratelimit_state, 5 * HZ, 10);
4205 
4206 	kfree(orig_data);
4207 	return 0;
4208 
4209 cantfind_ext4:
4210 	if (!silent)
4211 		ext4_msg(sb, KERN_ERR, "VFS: Can't find ext4 filesystem");
4212 	goto failed_mount;
4213 
4214 #ifdef CONFIG_QUOTA
4215 failed_mount8:
4216 	kobject_del(&sbi->s_kobj);
4217 #endif
4218 failed_mount7:
4219 	ext4_unregister_li_request(sb);
4220 failed_mount6:
4221 	ext4_release_system_zone(sb);
4222 failed_mount5:
4223 	dput(sb->s_root);
4224 	sb->s_root = NULL;
4225 failed_mount4:
4226 	ext4_msg(sb, KERN_ERR, "mount failed");
4227 	if (EXT4_SB(sb)->rsv_conversion_wq)
4228 		destroy_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
4229 failed_mount_wq:
4230 	if (sbi->s_journal) {
4231 		jbd2_journal_destroy(sbi->s_journal);
4232 		sbi->s_journal = NULL;
4233 	}
4234 failed_mount3:
4235 	ext4_es_unregister_shrinker(sbi);
4236 	del_timer_sync(&sbi->s_err_report);
4237 	if (sbi->s_flex_groups)
4238 		ext4_kvfree(sbi->s_flex_groups);
4239 	percpu_counter_destroy(&sbi->s_freeclusters_counter);
4240 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
4241 	percpu_counter_destroy(&sbi->s_dirs_counter);
4242 	percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
4243 	percpu_counter_destroy(&sbi->s_extent_cache_cnt);
4244 	if (sbi->s_mmp_tsk)
4245 		kthread_stop(sbi->s_mmp_tsk);
4246 failed_mount2a:
4247 	ext4_mb_release(sb);
4248 failed_mount2:
4249 	for (i = 0; i < db_count; i++)
4250 		brelse(sbi->s_group_desc[i]);
4251 	ext4_kvfree(sbi->s_group_desc);
4252 failed_mount:
4253 	ext4_ext_release(sb);
4254 	if (sbi->s_chksum_driver)
4255 		crypto_free_shash(sbi->s_chksum_driver);
4256 	if (sbi->s_proc) {
4257 		remove_proc_entry("options", sbi->s_proc);
4258 		remove_proc_entry(sb->s_id, ext4_proc_root);
4259 	}
4260 #ifdef CONFIG_QUOTA
4261 	for (i = 0; i < MAXQUOTAS; i++)
4262 		kfree(sbi->s_qf_names[i]);
4263 #endif
4264 	ext4_blkdev_remove(sbi);
4265 	brelse(bh);
4266 out_fail:
4267 	sb->s_fs_info = NULL;
4268 	kfree(sbi->s_blockgroup_lock);
4269 	kfree(sbi);
4270 out_free_orig:
4271 	kfree(orig_data);
4272 	return err ? err : ret;
4273 }
4274 
4275 /*
4276  * Setup any per-fs journal parameters now.  We'll do this both on
4277  * initial mount, once the journal has been initialised but before we've
4278  * done any recovery; and again on any subsequent remount.
4279  */
4280 static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
4281 {
4282 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4283 
4284 	journal->j_commit_interval = sbi->s_commit_interval;
4285 	journal->j_min_batch_time = sbi->s_min_batch_time;
4286 	journal->j_max_batch_time = sbi->s_max_batch_time;
4287 
4288 	write_lock(&journal->j_state_lock);
4289 	if (test_opt(sb, BARRIER))
4290 		journal->j_flags |= JBD2_BARRIER;
4291 	else
4292 		journal->j_flags &= ~JBD2_BARRIER;
4293 	if (test_opt(sb, DATA_ERR_ABORT))
4294 		journal->j_flags |= JBD2_ABORT_ON_SYNCDATA_ERR;
4295 	else
4296 		journal->j_flags &= ~JBD2_ABORT_ON_SYNCDATA_ERR;
4297 	write_unlock(&journal->j_state_lock);
4298 }
4299 
4300 static journal_t *ext4_get_journal(struct super_block *sb,
4301 				   unsigned int journal_inum)
4302 {
4303 	struct inode *journal_inode;
4304 	journal_t *journal;
4305 
4306 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4307 
4308 	/* First, test for the existence of a valid inode on disk.  Bad
4309 	 * things happen if we iget() an unused inode, as the subsequent
4310 	 * iput() will try to delete it. */
4311 
4312 	journal_inode = ext4_iget(sb, journal_inum);
4313 	if (IS_ERR(journal_inode)) {
4314 		ext4_msg(sb, KERN_ERR, "no journal found");
4315 		return NULL;
4316 	}
4317 	if (!journal_inode->i_nlink) {
4318 		make_bad_inode(journal_inode);
4319 		iput(journal_inode);
4320 		ext4_msg(sb, KERN_ERR, "journal inode is deleted");
4321 		return NULL;
4322 	}
4323 
4324 	jbd_debug(2, "Journal inode found at %p: %lld bytes\n",
4325 		  journal_inode, journal_inode->i_size);
4326 	if (!S_ISREG(journal_inode->i_mode)) {
4327 		ext4_msg(sb, KERN_ERR, "invalid journal inode");
4328 		iput(journal_inode);
4329 		return NULL;
4330 	}
4331 
4332 	journal = jbd2_journal_init_inode(journal_inode);
4333 	if (!journal) {
4334 		ext4_msg(sb, KERN_ERR, "Could not load journal inode");
4335 		iput(journal_inode);
4336 		return NULL;
4337 	}
4338 	journal->j_private = sb;
4339 	ext4_init_journal_params(sb, journal);
4340 	return journal;
4341 }
4342 
4343 static journal_t *ext4_get_dev_journal(struct super_block *sb,
4344 				       dev_t j_dev)
4345 {
4346 	struct buffer_head *bh;
4347 	journal_t *journal;
4348 	ext4_fsblk_t start;
4349 	ext4_fsblk_t len;
4350 	int hblock, blocksize;
4351 	ext4_fsblk_t sb_block;
4352 	unsigned long offset;
4353 	struct ext4_super_block *es;
4354 	struct block_device *bdev;
4355 
4356 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4357 
4358 	bdev = ext4_blkdev_get(j_dev, sb);
4359 	if (bdev == NULL)
4360 		return NULL;
4361 
4362 	blocksize = sb->s_blocksize;
4363 	hblock = bdev_logical_block_size(bdev);
4364 	if (blocksize < hblock) {
4365 		ext4_msg(sb, KERN_ERR,
4366 			"blocksize too small for journal device");
4367 		goto out_bdev;
4368 	}
4369 
4370 	sb_block = EXT4_MIN_BLOCK_SIZE / blocksize;
4371 	offset = EXT4_MIN_BLOCK_SIZE % blocksize;
4372 	set_blocksize(bdev, blocksize);
4373 	if (!(bh = __bread(bdev, sb_block, blocksize))) {
4374 		ext4_msg(sb, KERN_ERR, "couldn't read superblock of "
4375 		       "external journal");
4376 		goto out_bdev;
4377 	}
4378 
4379 	es = (struct ext4_super_block *) (bh->b_data + offset);
4380 	if ((le16_to_cpu(es->s_magic) != EXT4_SUPER_MAGIC) ||
4381 	    !(le32_to_cpu(es->s_feature_incompat) &
4382 	      EXT4_FEATURE_INCOMPAT_JOURNAL_DEV)) {
4383 		ext4_msg(sb, KERN_ERR, "external journal has "
4384 					"bad superblock");
4385 		brelse(bh);
4386 		goto out_bdev;
4387 	}
4388 
4389 	if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
4390 		ext4_msg(sb, KERN_ERR, "journal UUID does not match");
4391 		brelse(bh);
4392 		goto out_bdev;
4393 	}
4394 
4395 	len = ext4_blocks_count(es);
4396 	start = sb_block + 1;
4397 	brelse(bh);	/* we're done with the superblock */
4398 
4399 	journal = jbd2_journal_init_dev(bdev, sb->s_bdev,
4400 					start, len, blocksize);
4401 	if (!journal) {
4402 		ext4_msg(sb, KERN_ERR, "failed to create device journal");
4403 		goto out_bdev;
4404 	}
4405 	journal->j_private = sb;
4406 	ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &journal->j_sb_buffer);
4407 	wait_on_buffer(journal->j_sb_buffer);
4408 	if (!buffer_uptodate(journal->j_sb_buffer)) {
4409 		ext4_msg(sb, KERN_ERR, "I/O error on journal device");
4410 		goto out_journal;
4411 	}
4412 	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
4413 		ext4_msg(sb, KERN_ERR, "External journal has more than one "
4414 					"user (unsupported) - %d",
4415 			be32_to_cpu(journal->j_superblock->s_nr_users));
4416 		goto out_journal;
4417 	}
4418 	EXT4_SB(sb)->journal_bdev = bdev;
4419 	ext4_init_journal_params(sb, journal);
4420 	return journal;
4421 
4422 out_journal:
4423 	jbd2_journal_destroy(journal);
4424 out_bdev:
4425 	ext4_blkdev_put(bdev);
4426 	return NULL;
4427 }
4428 
4429 static int ext4_load_journal(struct super_block *sb,
4430 			     struct ext4_super_block *es,
4431 			     unsigned long journal_devnum)
4432 {
4433 	journal_t *journal;
4434 	unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
4435 	dev_t journal_dev;
4436 	int err = 0;
4437 	int really_read_only;
4438 
4439 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4440 
4441 	if (journal_devnum &&
4442 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
4443 		ext4_msg(sb, KERN_INFO, "external journal device major/minor "
4444 			"numbers have changed");
4445 		journal_dev = new_decode_dev(journal_devnum);
4446 	} else
4447 		journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));
4448 
4449 	really_read_only = bdev_read_only(sb->s_bdev);
4450 
4451 	/*
4452 	 * Are we loading a blank journal or performing recovery after a
4453 	 * crash?  For recovery, we need to check in advance whether we
4454 	 * can get read-write access to the device.
4455 	 */
4456 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
4457 		if (sb->s_flags & MS_RDONLY) {
4458 			ext4_msg(sb, KERN_INFO, "INFO: recovery "
4459 					"required on readonly filesystem");
4460 			if (really_read_only) {
4461 				ext4_msg(sb, KERN_ERR, "write access "
4462 					"unavailable, cannot proceed");
4463 				return -EROFS;
4464 			}
4465 			ext4_msg(sb, KERN_INFO, "write access will "
4466 			       "be enabled during recovery");
4467 		}
4468 	}
4469 
4470 	if (journal_inum && journal_dev) {
4471 		ext4_msg(sb, KERN_ERR, "filesystem has both journal "
4472 		       "and inode journals!");
4473 		return -EINVAL;
4474 	}
4475 
4476 	if (journal_inum) {
4477 		if (!(journal = ext4_get_journal(sb, journal_inum)))
4478 			return -EINVAL;
4479 	} else {
4480 		if (!(journal = ext4_get_dev_journal(sb, journal_dev)))
4481 			return -EINVAL;
4482 	}
4483 
4484 	if (!(journal->j_flags & JBD2_BARRIER))
4485 		ext4_msg(sb, KERN_INFO, "barriers disabled");
4486 
4487 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER))
4488 		err = jbd2_journal_wipe(journal, !really_read_only);
4489 	if (!err) {
4490 		char *save = kmalloc(EXT4_S_ERR_LEN, GFP_KERNEL);
4491 		if (save)
4492 			memcpy(save, ((char *) es) +
4493 			       EXT4_S_ERR_START, EXT4_S_ERR_LEN);
4494 		err = jbd2_journal_load(journal);
4495 		if (save)
4496 			memcpy(((char *) es) + EXT4_S_ERR_START,
4497 			       save, EXT4_S_ERR_LEN);
4498 		kfree(save);
4499 	}
4500 
4501 	if (err) {
4502 		ext4_msg(sb, KERN_ERR, "error loading journal");
4503 		jbd2_journal_destroy(journal);
4504 		return err;
4505 	}
4506 
4507 	EXT4_SB(sb)->s_journal = journal;
4508 	ext4_clear_journal_err(sb, es);
4509 
4510 	if (!really_read_only && journal_devnum &&
4511 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
4512 		es->s_journal_dev = cpu_to_le32(journal_devnum);
4513 
4514 		/* Make sure we flush the recovery flag to disk. */
4515 		ext4_commit_super(sb, 1);
4516 	}
4517 
4518 	return 0;
4519 }
4520 
4521 static int ext4_commit_super(struct super_block *sb, int sync)
4522 {
4523 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
4524 	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
4525 	int error = 0;
4526 
4527 	if (!sbh || block_device_ejected(sb))
4528 		return error;
4529 	if (buffer_write_io_error(sbh)) {
4530 		/*
4531 		 * Oh, dear.  A previous attempt to write the
4532 		 * superblock failed.  This could happen because the
4533 		 * USB device was yanked out.  Or it could happen to
4534 		 * be a transient write error and maybe the block will
4535 		 * be remapped.  Nothing we can do but to retry the
4536 		 * write and hope for the best.
4537 		 */
4538 		ext4_msg(sb, KERN_ERR, "previous I/O error to "
4539 		       "superblock detected");
4540 		clear_buffer_write_io_error(sbh);
4541 		set_buffer_uptodate(sbh);
4542 	}
4543 	/*
4544 	 * If the file system is mounted read-only, don't update the
4545 	 * superblock write time.  This avoids updating the superblock
4546 	 * write time when we are mounting the root file system
4547 	 * read/only but we need to replay the journal; at that point,
4548 	 * for people who are east of GMT and who make their clock
4549 	 * tick in localtime for Windows bug-for-bug compatibility,
4550 	 * the clock is set in the future, and this will cause e2fsck
4551 	 * to complain and force a full file system check.
4552 	 */
4553 	if (!(sb->s_flags & MS_RDONLY))
4554 		es->s_wtime = cpu_to_le32(get_seconds());
4555 	if (sb->s_bdev->bd_part)
4556 		es->s_kbytes_written =
4557 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written +
4558 			    ((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
4559 			      EXT4_SB(sb)->s_sectors_written_start) >> 1));
4560 	else
4561 		es->s_kbytes_written =
4562 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written);
4563 	ext4_free_blocks_count_set(es,
4564 			EXT4_C2B(EXT4_SB(sb), percpu_counter_sum_positive(
4565 				&EXT4_SB(sb)->s_freeclusters_counter)));
4566 	es->s_free_inodes_count =
4567 		cpu_to_le32(percpu_counter_sum_positive(
4568 				&EXT4_SB(sb)->s_freeinodes_counter));
4569 	BUFFER_TRACE(sbh, "marking dirty");
4570 	ext4_superblock_csum_set(sb);
4571 	mark_buffer_dirty(sbh);
4572 	if (sync) {
4573 		error = sync_dirty_buffer(sbh);
4574 		if (error)
4575 			return error;
4576 
4577 		error = buffer_write_io_error(sbh);
4578 		if (error) {
4579 			ext4_msg(sb, KERN_ERR, "I/O error while writing "
4580 			       "superblock");
4581 			clear_buffer_write_io_error(sbh);
4582 			set_buffer_uptodate(sbh);
4583 		}
4584 	}
4585 	return error;
4586 }
4587 
4588 /*
4589  * Have we just finished recovery?  If so, and if we are mounting (or
4590  * remounting) the filesystem readonly, then we will end up with a
4591  * consistent fs on disk.  Record that fact.
4592  */
4593 static void ext4_mark_recovery_complete(struct super_block *sb,
4594 					struct ext4_super_block *es)
4595 {
4596 	journal_t *journal = EXT4_SB(sb)->s_journal;
4597 
4598 	if (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
4599 		BUG_ON(journal != NULL);
4600 		return;
4601 	}
4602 	jbd2_journal_lock_updates(journal);
4603 	if (jbd2_journal_flush(journal) < 0)
4604 		goto out;
4605 
4606 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER) &&
4607 	    sb->s_flags & MS_RDONLY) {
4608 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4609 		ext4_commit_super(sb, 1);
4610 	}
4611 
4612 out:
4613 	jbd2_journal_unlock_updates(journal);
4614 }
4615 
4616 /*
4617  * If we are mounting (or read-write remounting) a filesystem whose journal
4618  * has recorded an error from a previous lifetime, move that error to the
4619  * main filesystem now.
4620  */
4621 static void ext4_clear_journal_err(struct super_block *sb,
4622 				   struct ext4_super_block *es)
4623 {
4624 	journal_t *journal;
4625 	int j_errno;
4626 	const char *errstr;
4627 
4628 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4629 
4630 	journal = EXT4_SB(sb)->s_journal;
4631 
4632 	/*
4633 	 * Now check for any error status which may have been recorded in the
4634 	 * journal by a prior ext4_error() or ext4_abort()
4635 	 */
4636 
4637 	j_errno = jbd2_journal_errno(journal);
4638 	if (j_errno) {
4639 		char nbuf[16];
4640 
4641 		errstr = ext4_decode_error(sb, j_errno, nbuf);
4642 		ext4_warning(sb, "Filesystem error recorded "
4643 			     "from previous mount: %s", errstr);
4644 		ext4_warning(sb, "Marking fs in need of filesystem check.");
4645 
4646 		EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
4647 		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
4648 		ext4_commit_super(sb, 1);
4649 
4650 		jbd2_journal_clear_err(journal);
4651 		jbd2_journal_update_sb_errno(journal);
4652 	}
4653 }
4654 
4655 /*
4656  * Force the running and committing transactions to commit,
4657  * and wait on the commit.
4658  */
4659 int ext4_force_commit(struct super_block *sb)
4660 {
4661 	journal_t *journal;
4662 
4663 	if (sb->s_flags & MS_RDONLY)
4664 		return 0;
4665 
4666 	journal = EXT4_SB(sb)->s_journal;
4667 	return ext4_journal_force_commit(journal);
4668 }
4669 
4670 static int ext4_sync_fs(struct super_block *sb, int wait)
4671 {
4672 	int ret = 0;
4673 	tid_t target;
4674 	bool needs_barrier = false;
4675 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4676 
4677 	trace_ext4_sync_fs(sb, wait);
4678 	flush_workqueue(sbi->rsv_conversion_wq);
4679 	/*
4680 	 * Writeback quota in non-journalled quota case - journalled quota has
4681 	 * no dirty dquots
4682 	 */
4683 	dquot_writeback_dquots(sb, -1);
4684 	/*
4685 	 * Data writeback is possible w/o journal transaction, so barrier must
4686 	 * being sent at the end of the function. But we can skip it if
4687 	 * transaction_commit will do it for us.
4688 	 */
4689 	target = jbd2_get_latest_transaction(sbi->s_journal);
4690 	if (wait && sbi->s_journal->j_flags & JBD2_BARRIER &&
4691 	    !jbd2_trans_will_send_data_barrier(sbi->s_journal, target))
4692 		needs_barrier = true;
4693 
4694 	if (jbd2_journal_start_commit(sbi->s_journal, &target)) {
4695 		if (wait)
4696 			ret = jbd2_log_wait_commit(sbi->s_journal, target);
4697 	}
4698 	if (needs_barrier) {
4699 		int err;
4700 		err = blkdev_issue_flush(sb->s_bdev, GFP_KERNEL, NULL);
4701 		if (!ret)
4702 			ret = err;
4703 	}
4704 
4705 	return ret;
4706 }
4707 
4708 static int ext4_sync_fs_nojournal(struct super_block *sb, int wait)
4709 {
4710 	int ret = 0;
4711 
4712 	trace_ext4_sync_fs(sb, wait);
4713 	flush_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
4714 	dquot_writeback_dquots(sb, -1);
4715 	if (wait && test_opt(sb, BARRIER))
4716 		ret = blkdev_issue_flush(sb->s_bdev, GFP_KERNEL, NULL);
4717 
4718 	return ret;
4719 }
4720 
4721 /*
4722  * LVM calls this function before a (read-only) snapshot is created.  This
4723  * gives us a chance to flush the journal completely and mark the fs clean.
4724  *
4725  * Note that only this function cannot bring a filesystem to be in a clean
4726  * state independently. It relies on upper layer to stop all data & metadata
4727  * modifications.
4728  */
4729 static int ext4_freeze(struct super_block *sb)
4730 {
4731 	int error = 0;
4732 	journal_t *journal;
4733 
4734 	if (sb->s_flags & MS_RDONLY)
4735 		return 0;
4736 
4737 	journal = EXT4_SB(sb)->s_journal;
4738 
4739 	/* Now we set up the journal barrier. */
4740 	jbd2_journal_lock_updates(journal);
4741 
4742 	/*
4743 	 * Don't clear the needs_recovery flag if we failed to flush
4744 	 * the journal.
4745 	 */
4746 	error = jbd2_journal_flush(journal);
4747 	if (error < 0)
4748 		goto out;
4749 
4750 	/* Journal blocked and flushed, clear needs_recovery flag. */
4751 	EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4752 	error = ext4_commit_super(sb, 1);
4753 out:
4754 	/* we rely on upper layer to stop further updates */
4755 	jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
4756 	return error;
4757 }
4758 
4759 /*
4760  * Called by LVM after the snapshot is done.  We need to reset the RECOVER
4761  * flag here, even though the filesystem is not technically dirty yet.
4762  */
4763 static int ext4_unfreeze(struct super_block *sb)
4764 {
4765 	if (sb->s_flags & MS_RDONLY)
4766 		return 0;
4767 
4768 	/* Reset the needs_recovery flag before the fs is unlocked. */
4769 	EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4770 	ext4_commit_super(sb, 1);
4771 	return 0;
4772 }
4773 
4774 /*
4775  * Structure to save mount options for ext4_remount's benefit
4776  */
4777 struct ext4_mount_options {
4778 	unsigned long s_mount_opt;
4779 	unsigned long s_mount_opt2;
4780 	kuid_t s_resuid;
4781 	kgid_t s_resgid;
4782 	unsigned long s_commit_interval;
4783 	u32 s_min_batch_time, s_max_batch_time;
4784 #ifdef CONFIG_QUOTA
4785 	int s_jquota_fmt;
4786 	char *s_qf_names[MAXQUOTAS];
4787 #endif
4788 };
4789 
4790 static int ext4_remount(struct super_block *sb, int *flags, char *data)
4791 {
4792 	struct ext4_super_block *es;
4793 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4794 	unsigned long old_sb_flags;
4795 	struct ext4_mount_options old_opts;
4796 	int enable_quota = 0;
4797 	ext4_group_t g;
4798 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
4799 	int err = 0;
4800 #ifdef CONFIG_QUOTA
4801 	int i, j;
4802 #endif
4803 	char *orig_data = kstrdup(data, GFP_KERNEL);
4804 
4805 	/* Store the original options */
4806 	old_sb_flags = sb->s_flags;
4807 	old_opts.s_mount_opt = sbi->s_mount_opt;
4808 	old_opts.s_mount_opt2 = sbi->s_mount_opt2;
4809 	old_opts.s_resuid = sbi->s_resuid;
4810 	old_opts.s_resgid = sbi->s_resgid;
4811 	old_opts.s_commit_interval = sbi->s_commit_interval;
4812 	old_opts.s_min_batch_time = sbi->s_min_batch_time;
4813 	old_opts.s_max_batch_time = sbi->s_max_batch_time;
4814 #ifdef CONFIG_QUOTA
4815 	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
4816 	for (i = 0; i < MAXQUOTAS; i++)
4817 		if (sbi->s_qf_names[i]) {
4818 			old_opts.s_qf_names[i] = kstrdup(sbi->s_qf_names[i],
4819 							 GFP_KERNEL);
4820 			if (!old_opts.s_qf_names[i]) {
4821 				for (j = 0; j < i; j++)
4822 					kfree(old_opts.s_qf_names[j]);
4823 				kfree(orig_data);
4824 				return -ENOMEM;
4825 			}
4826 		} else
4827 			old_opts.s_qf_names[i] = NULL;
4828 #endif
4829 	if (sbi->s_journal && sbi->s_journal->j_task->io_context)
4830 		journal_ioprio = sbi->s_journal->j_task->io_context->ioprio;
4831 
4832 	/*
4833 	 * Allow the "check" option to be passed as a remount option.
4834 	 */
4835 	if (!parse_options(data, sb, NULL, &journal_ioprio, 1)) {
4836 		err = -EINVAL;
4837 		goto restore_opts;
4838 	}
4839 
4840 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
4841 		if (test_opt2(sb, EXPLICIT_DELALLOC)) {
4842 			ext4_msg(sb, KERN_ERR, "can't mount with "
4843 				 "both data=journal and delalloc");
4844 			err = -EINVAL;
4845 			goto restore_opts;
4846 		}
4847 		if (test_opt(sb, DIOREAD_NOLOCK)) {
4848 			ext4_msg(sb, KERN_ERR, "can't mount with "
4849 				 "both data=journal and dioread_nolock");
4850 			err = -EINVAL;
4851 			goto restore_opts;
4852 		}
4853 	}
4854 
4855 	if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
4856 		ext4_abort(sb, "Abort forced by user");
4857 
4858 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
4859 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
4860 
4861 	es = sbi->s_es;
4862 
4863 	if (sbi->s_journal) {
4864 		ext4_init_journal_params(sb, sbi->s_journal);
4865 		set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
4866 	}
4867 
4868 	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY)) {
4869 		if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) {
4870 			err = -EROFS;
4871 			goto restore_opts;
4872 		}
4873 
4874 		if (*flags & MS_RDONLY) {
4875 			err = sync_filesystem(sb);
4876 			if (err < 0)
4877 				goto restore_opts;
4878 			err = dquot_suspend(sb, -1);
4879 			if (err < 0)
4880 				goto restore_opts;
4881 
4882 			/*
4883 			 * First of all, the unconditional stuff we have to do
4884 			 * to disable replay of the journal when we next remount
4885 			 */
4886 			sb->s_flags |= MS_RDONLY;
4887 
4888 			/*
4889 			 * OK, test if we are remounting a valid rw partition
4890 			 * readonly, and if so set the rdonly flag and then
4891 			 * mark the partition as valid again.
4892 			 */
4893 			if (!(es->s_state & cpu_to_le16(EXT4_VALID_FS)) &&
4894 			    (sbi->s_mount_state & EXT4_VALID_FS))
4895 				es->s_state = cpu_to_le16(sbi->s_mount_state);
4896 
4897 			if (sbi->s_journal)
4898 				ext4_mark_recovery_complete(sb, es);
4899 		} else {
4900 			/* Make sure we can mount this feature set readwrite */
4901 			if (!ext4_feature_set_ok(sb, 0)) {
4902 				err = -EROFS;
4903 				goto restore_opts;
4904 			}
4905 			/*
4906 			 * Make sure the group descriptor checksums
4907 			 * are sane.  If they aren't, refuse to remount r/w.
4908 			 */
4909 			for (g = 0; g < sbi->s_groups_count; g++) {
4910 				struct ext4_group_desc *gdp =
4911 					ext4_get_group_desc(sb, g, NULL);
4912 
4913 				if (!ext4_group_desc_csum_verify(sb, g, gdp)) {
4914 					ext4_msg(sb, KERN_ERR,
4915 	       "ext4_remount: Checksum for group %u failed (%u!=%u)",
4916 		g, le16_to_cpu(ext4_group_desc_csum(sbi, g, gdp)),
4917 					       le16_to_cpu(gdp->bg_checksum));
4918 					err = -EINVAL;
4919 					goto restore_opts;
4920 				}
4921 			}
4922 
4923 			/*
4924 			 * If we have an unprocessed orphan list hanging
4925 			 * around from a previously readonly bdev mount,
4926 			 * require a full umount/remount for now.
4927 			 */
4928 			if (es->s_last_orphan) {
4929 				ext4_msg(sb, KERN_WARNING, "Couldn't "
4930 				       "remount RDWR because of unprocessed "
4931 				       "orphan inode list.  Please "
4932 				       "umount/remount instead");
4933 				err = -EINVAL;
4934 				goto restore_opts;
4935 			}
4936 
4937 			/*
4938 			 * Mounting a RDONLY partition read-write, so reread
4939 			 * and store the current valid flag.  (It may have
4940 			 * been changed by e2fsck since we originally mounted
4941 			 * the partition.)
4942 			 */
4943 			if (sbi->s_journal)
4944 				ext4_clear_journal_err(sb, es);
4945 			sbi->s_mount_state = le16_to_cpu(es->s_state);
4946 			if (!ext4_setup_super(sb, es, 0))
4947 				sb->s_flags &= ~MS_RDONLY;
4948 			if (EXT4_HAS_INCOMPAT_FEATURE(sb,
4949 						     EXT4_FEATURE_INCOMPAT_MMP))
4950 				if (ext4_multi_mount_protect(sb,
4951 						le64_to_cpu(es->s_mmp_block))) {
4952 					err = -EROFS;
4953 					goto restore_opts;
4954 				}
4955 			enable_quota = 1;
4956 		}
4957 	}
4958 
4959 	/*
4960 	 * Reinitialize lazy itable initialization thread based on
4961 	 * current settings
4962 	 */
4963 	if ((sb->s_flags & MS_RDONLY) || !test_opt(sb, INIT_INODE_TABLE))
4964 		ext4_unregister_li_request(sb);
4965 	else {
4966 		ext4_group_t first_not_zeroed;
4967 		first_not_zeroed = ext4_has_uninit_itable(sb);
4968 		ext4_register_li_request(sb, first_not_zeroed);
4969 	}
4970 
4971 	ext4_setup_system_zone(sb);
4972 	if (sbi->s_journal == NULL && !(old_sb_flags & MS_RDONLY))
4973 		ext4_commit_super(sb, 1);
4974 
4975 #ifdef CONFIG_QUOTA
4976 	/* Release old quota file names */
4977 	for (i = 0; i < MAXQUOTAS; i++)
4978 		kfree(old_opts.s_qf_names[i]);
4979 	if (enable_quota) {
4980 		if (sb_any_quota_suspended(sb))
4981 			dquot_resume(sb, -1);
4982 		else if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
4983 					EXT4_FEATURE_RO_COMPAT_QUOTA)) {
4984 			err = ext4_enable_quotas(sb);
4985 			if (err)
4986 				goto restore_opts;
4987 		}
4988 	}
4989 #endif
4990 
4991 	ext4_msg(sb, KERN_INFO, "re-mounted. Opts: %s", orig_data);
4992 	kfree(orig_data);
4993 	return 0;
4994 
4995 restore_opts:
4996 	sb->s_flags = old_sb_flags;
4997 	sbi->s_mount_opt = old_opts.s_mount_opt;
4998 	sbi->s_mount_opt2 = old_opts.s_mount_opt2;
4999 	sbi->s_resuid = old_opts.s_resuid;
5000 	sbi->s_resgid = old_opts.s_resgid;
5001 	sbi->s_commit_interval = old_opts.s_commit_interval;
5002 	sbi->s_min_batch_time = old_opts.s_min_batch_time;
5003 	sbi->s_max_batch_time = old_opts.s_max_batch_time;
5004 #ifdef CONFIG_QUOTA
5005 	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
5006 	for (i = 0; i < MAXQUOTAS; i++) {
5007 		kfree(sbi->s_qf_names[i]);
5008 		sbi->s_qf_names[i] = old_opts.s_qf_names[i];
5009 	}
5010 #endif
5011 	kfree(orig_data);
5012 	return err;
5013 }
5014 
5015 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
5016 {
5017 	struct super_block *sb = dentry->d_sb;
5018 	struct ext4_sb_info *sbi = EXT4_SB(sb);
5019 	struct ext4_super_block *es = sbi->s_es;
5020 	ext4_fsblk_t overhead = 0, resv_blocks;
5021 	u64 fsid;
5022 	s64 bfree;
5023 	resv_blocks = EXT4_C2B(sbi, atomic64_read(&sbi->s_resv_clusters));
5024 
5025 	if (!test_opt(sb, MINIX_DF))
5026 		overhead = sbi->s_overhead;
5027 
5028 	buf->f_type = EXT4_SUPER_MAGIC;
5029 	buf->f_bsize = sb->s_blocksize;
5030 	buf->f_blocks = ext4_blocks_count(es) - EXT4_C2B(sbi, overhead);
5031 	bfree = percpu_counter_sum_positive(&sbi->s_freeclusters_counter) -
5032 		percpu_counter_sum_positive(&sbi->s_dirtyclusters_counter);
5033 	/* prevent underflow in case that few free space is available */
5034 	buf->f_bfree = EXT4_C2B(sbi, max_t(s64, bfree, 0));
5035 	buf->f_bavail = buf->f_bfree -
5036 			(ext4_r_blocks_count(es) + resv_blocks);
5037 	if (buf->f_bfree < (ext4_r_blocks_count(es) + resv_blocks))
5038 		buf->f_bavail = 0;
5039 	buf->f_files = le32_to_cpu(es->s_inodes_count);
5040 	buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter);
5041 	buf->f_namelen = EXT4_NAME_LEN;
5042 	fsid = le64_to_cpup((void *)es->s_uuid) ^
5043 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
5044 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
5045 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
5046 
5047 	return 0;
5048 }
5049 
5050 /* Helper function for writing quotas on sync - we need to start transaction
5051  * before quota file is locked for write. Otherwise the are possible deadlocks:
5052  * Process 1                         Process 2
5053  * ext4_create()                     quota_sync()
5054  *   jbd2_journal_start()                  write_dquot()
5055  *   dquot_initialize()                         down(dqio_mutex)
5056  *     down(dqio_mutex)                    jbd2_journal_start()
5057  *
5058  */
5059 
5060 #ifdef CONFIG_QUOTA
5061 
5062 static inline struct inode *dquot_to_inode(struct dquot *dquot)
5063 {
5064 	return sb_dqopt(dquot->dq_sb)->files[dquot->dq_id.type];
5065 }
5066 
5067 static int ext4_write_dquot(struct dquot *dquot)
5068 {
5069 	int ret, err;
5070 	handle_t *handle;
5071 	struct inode *inode;
5072 
5073 	inode = dquot_to_inode(dquot);
5074 	handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
5075 				    EXT4_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
5076 	if (IS_ERR(handle))
5077 		return PTR_ERR(handle);
5078 	ret = dquot_commit(dquot);
5079 	err = ext4_journal_stop(handle);
5080 	if (!ret)
5081 		ret = err;
5082 	return ret;
5083 }
5084 
5085 static int ext4_acquire_dquot(struct dquot *dquot)
5086 {
5087 	int ret, err;
5088 	handle_t *handle;
5089 
5090 	handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
5091 				    EXT4_QUOTA_INIT_BLOCKS(dquot->dq_sb));
5092 	if (IS_ERR(handle))
5093 		return PTR_ERR(handle);
5094 	ret = dquot_acquire(dquot);
5095 	err = ext4_journal_stop(handle);
5096 	if (!ret)
5097 		ret = err;
5098 	return ret;
5099 }
5100 
5101 static int ext4_release_dquot(struct dquot *dquot)
5102 {
5103 	int ret, err;
5104 	handle_t *handle;
5105 
5106 	handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
5107 				    EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
5108 	if (IS_ERR(handle)) {
5109 		/* Release dquot anyway to avoid endless cycle in dqput() */
5110 		dquot_release(dquot);
5111 		return PTR_ERR(handle);
5112 	}
5113 	ret = dquot_release(dquot);
5114 	err = ext4_journal_stop(handle);
5115 	if (!ret)
5116 		ret = err;
5117 	return ret;
5118 }
5119 
5120 static int ext4_mark_dquot_dirty(struct dquot *dquot)
5121 {
5122 	struct super_block *sb = dquot->dq_sb;
5123 	struct ext4_sb_info *sbi = EXT4_SB(sb);
5124 
5125 	/* Are we journaling quotas? */
5126 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA) ||
5127 	    sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
5128 		dquot_mark_dquot_dirty(dquot);
5129 		return ext4_write_dquot(dquot);
5130 	} else {
5131 		return dquot_mark_dquot_dirty(dquot);
5132 	}
5133 }
5134 
5135 static int ext4_write_info(struct super_block *sb, int type)
5136 {
5137 	int ret, err;
5138 	handle_t *handle;
5139 
5140 	/* Data block + inode block */
5141 	handle = ext4_journal_start(sb->s_root->d_inode, EXT4_HT_QUOTA, 2);
5142 	if (IS_ERR(handle))
5143 		return PTR_ERR(handle);
5144 	ret = dquot_commit_info(sb, type);
5145 	err = ext4_journal_stop(handle);
5146 	if (!ret)
5147 		ret = err;
5148 	return ret;
5149 }
5150 
5151 /*
5152  * Turn on quotas during mount time - we need to find
5153  * the quota file and such...
5154  */
5155 static int ext4_quota_on_mount(struct super_block *sb, int type)
5156 {
5157 	return dquot_quota_on_mount(sb, EXT4_SB(sb)->s_qf_names[type],
5158 					EXT4_SB(sb)->s_jquota_fmt, type);
5159 }
5160 
5161 /*
5162  * Standard function to be called on quota_on
5163  */
5164 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
5165 			 struct path *path)
5166 {
5167 	int err;
5168 
5169 	if (!test_opt(sb, QUOTA))
5170 		return -EINVAL;
5171 
5172 	/* Quotafile not on the same filesystem? */
5173 	if (path->dentry->d_sb != sb)
5174 		return -EXDEV;
5175 	/* Journaling quota? */
5176 	if (EXT4_SB(sb)->s_qf_names[type]) {
5177 		/* Quotafile not in fs root? */
5178 		if (path->dentry->d_parent != sb->s_root)
5179 			ext4_msg(sb, KERN_WARNING,
5180 				"Quota file not on filesystem root. "
5181 				"Journaled quota will not work");
5182 	}
5183 
5184 	/*
5185 	 * When we journal data on quota file, we have to flush journal to see
5186 	 * all updates to the file when we bypass pagecache...
5187 	 */
5188 	if (EXT4_SB(sb)->s_journal &&
5189 	    ext4_should_journal_data(path->dentry->d_inode)) {
5190 		/*
5191 		 * We don't need to lock updates but journal_flush() could
5192 		 * otherwise be livelocked...
5193 		 */
5194 		jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
5195 		err = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
5196 		jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
5197 		if (err)
5198 			return err;
5199 	}
5200 
5201 	return dquot_quota_on(sb, type, format_id, path);
5202 }
5203 
5204 static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
5205 			     unsigned int flags)
5206 {
5207 	int err;
5208 	struct inode *qf_inode;
5209 	unsigned long qf_inums[MAXQUOTAS] = {
5210 		le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
5211 		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum)
5212 	};
5213 
5214 	BUG_ON(!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA));
5215 
5216 	if (!qf_inums[type])
5217 		return -EPERM;
5218 
5219 	qf_inode = ext4_iget(sb, qf_inums[type]);
5220 	if (IS_ERR(qf_inode)) {
5221 		ext4_error(sb, "Bad quota inode # %lu", qf_inums[type]);
5222 		return PTR_ERR(qf_inode);
5223 	}
5224 
5225 	/* Don't account quota for quota files to avoid recursion */
5226 	qf_inode->i_flags |= S_NOQUOTA;
5227 	err = dquot_enable(qf_inode, type, format_id, flags);
5228 	iput(qf_inode);
5229 
5230 	return err;
5231 }
5232 
5233 /* Enable usage tracking for all quota types. */
5234 static int ext4_enable_quotas(struct super_block *sb)
5235 {
5236 	int type, err = 0;
5237 	unsigned long qf_inums[MAXQUOTAS] = {
5238 		le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
5239 		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum)
5240 	};
5241 
5242 	sb_dqopt(sb)->flags |= DQUOT_QUOTA_SYS_FILE;
5243 	for (type = 0; type < MAXQUOTAS; type++) {
5244 		if (qf_inums[type]) {
5245 			err = ext4_quota_enable(sb, type, QFMT_VFS_V1,
5246 						DQUOT_USAGE_ENABLED);
5247 			if (err) {
5248 				ext4_warning(sb,
5249 					"Failed to enable quota tracking "
5250 					"(type=%d, err=%d). Please run "
5251 					"e2fsck to fix.", type, err);
5252 				return err;
5253 			}
5254 		}
5255 	}
5256 	return 0;
5257 }
5258 
5259 /*
5260  * quota_on function that is used when QUOTA feature is set.
5261  */
5262 static int ext4_quota_on_sysfile(struct super_block *sb, int type,
5263 				 int format_id)
5264 {
5265 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA))
5266 		return -EINVAL;
5267 
5268 	/*
5269 	 * USAGE was enabled at mount time. Only need to enable LIMITS now.
5270 	 */
5271 	return ext4_quota_enable(sb, type, format_id, DQUOT_LIMITS_ENABLED);
5272 }
5273 
5274 static int ext4_quota_off(struct super_block *sb, int type)
5275 {
5276 	struct inode *inode = sb_dqopt(sb)->files[type];
5277 	handle_t *handle;
5278 
5279 	/* Force all delayed allocation blocks to be allocated.
5280 	 * Caller already holds s_umount sem */
5281 	if (test_opt(sb, DELALLOC))
5282 		sync_filesystem(sb);
5283 
5284 	if (!inode)
5285 		goto out;
5286 
5287 	/* Update modification times of quota files when userspace can
5288 	 * start looking at them */
5289 	handle = ext4_journal_start(inode, EXT4_HT_QUOTA, 1);
5290 	if (IS_ERR(handle))
5291 		goto out;
5292 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
5293 	ext4_mark_inode_dirty(handle, inode);
5294 	ext4_journal_stop(handle);
5295 
5296 out:
5297 	return dquot_quota_off(sb, type);
5298 }
5299 
5300 /*
5301  * quota_off function that is used when QUOTA feature is set.
5302  */
5303 static int ext4_quota_off_sysfile(struct super_block *sb, int type)
5304 {
5305 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA))
5306 		return -EINVAL;
5307 
5308 	/* Disable only the limits. */
5309 	return dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
5310 }
5311 
5312 /* Read data from quotafile - avoid pagecache and such because we cannot afford
5313  * acquiring the locks... As quota files are never truncated and quota code
5314  * itself serializes the operations (and no one else should touch the files)
5315  * we don't have to be afraid of races */
5316 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
5317 			       size_t len, loff_t off)
5318 {
5319 	struct inode *inode = sb_dqopt(sb)->files[type];
5320 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
5321 	int err = 0;
5322 	int offset = off & (sb->s_blocksize - 1);
5323 	int tocopy;
5324 	size_t toread;
5325 	struct buffer_head *bh;
5326 	loff_t i_size = i_size_read(inode);
5327 
5328 	if (off > i_size)
5329 		return 0;
5330 	if (off+len > i_size)
5331 		len = i_size-off;
5332 	toread = len;
5333 	while (toread > 0) {
5334 		tocopy = sb->s_blocksize - offset < toread ?
5335 				sb->s_blocksize - offset : toread;
5336 		bh = ext4_bread(NULL, inode, blk, 0, &err);
5337 		if (err)
5338 			return err;
5339 		if (!bh)	/* A hole? */
5340 			memset(data, 0, tocopy);
5341 		else
5342 			memcpy(data, bh->b_data+offset, tocopy);
5343 		brelse(bh);
5344 		offset = 0;
5345 		toread -= tocopy;
5346 		data += tocopy;
5347 		blk++;
5348 	}
5349 	return len;
5350 }
5351 
5352 /* Write to quotafile (we know the transaction is already started and has
5353  * enough credits) */
5354 static ssize_t ext4_quota_write(struct super_block *sb, int type,
5355 				const char *data, size_t len, loff_t off)
5356 {
5357 	struct inode *inode = sb_dqopt(sb)->files[type];
5358 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
5359 	int err = 0;
5360 	int offset = off & (sb->s_blocksize - 1);
5361 	struct buffer_head *bh;
5362 	handle_t *handle = journal_current_handle();
5363 
5364 	if (EXT4_SB(sb)->s_journal && !handle) {
5365 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
5366 			" cancelled because transaction is not started",
5367 			(unsigned long long)off, (unsigned long long)len);
5368 		return -EIO;
5369 	}
5370 	/*
5371 	 * Since we account only one data block in transaction credits,
5372 	 * then it is impossible to cross a block boundary.
5373 	 */
5374 	if (sb->s_blocksize - offset < len) {
5375 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
5376 			" cancelled because not block aligned",
5377 			(unsigned long long)off, (unsigned long long)len);
5378 		return -EIO;
5379 	}
5380 
5381 	bh = ext4_bread(handle, inode, blk, 1, &err);
5382 	if (!bh)
5383 		goto out;
5384 	BUFFER_TRACE(bh, "get write access");
5385 	err = ext4_journal_get_write_access(handle, bh);
5386 	if (err) {
5387 		brelse(bh);
5388 		goto out;
5389 	}
5390 	lock_buffer(bh);
5391 	memcpy(bh->b_data+offset, data, len);
5392 	flush_dcache_page(bh->b_page);
5393 	unlock_buffer(bh);
5394 	err = ext4_handle_dirty_metadata(handle, NULL, bh);
5395 	brelse(bh);
5396 out:
5397 	if (err)
5398 		return err;
5399 	if (inode->i_size < off + len) {
5400 		i_size_write(inode, off + len);
5401 		EXT4_I(inode)->i_disksize = inode->i_size;
5402 		ext4_mark_inode_dirty(handle, inode);
5403 	}
5404 	return len;
5405 }
5406 
5407 #endif
5408 
5409 static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
5410 		       const char *dev_name, void *data)
5411 {
5412 	return mount_bdev(fs_type, flags, dev_name, data, ext4_fill_super);
5413 }
5414 
5415 #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
5416 static inline void register_as_ext2(void)
5417 {
5418 	int err = register_filesystem(&ext2_fs_type);
5419 	if (err)
5420 		printk(KERN_WARNING
5421 		       "EXT4-fs: Unable to register as ext2 (%d)\n", err);
5422 }
5423 
5424 static inline void unregister_as_ext2(void)
5425 {
5426 	unregister_filesystem(&ext2_fs_type);
5427 }
5428 
5429 static inline int ext2_feature_set_ok(struct super_block *sb)
5430 {
5431 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP))
5432 		return 0;
5433 	if (sb->s_flags & MS_RDONLY)
5434 		return 1;
5435 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))
5436 		return 0;
5437 	return 1;
5438 }
5439 #else
5440 static inline void register_as_ext2(void) { }
5441 static inline void unregister_as_ext2(void) { }
5442 static inline int ext2_feature_set_ok(struct super_block *sb) { return 0; }
5443 #endif
5444 
5445 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
5446 static inline void register_as_ext3(void)
5447 {
5448 	int err = register_filesystem(&ext3_fs_type);
5449 	if (err)
5450 		printk(KERN_WARNING
5451 		       "EXT4-fs: Unable to register as ext3 (%d)\n", err);
5452 }
5453 
5454 static inline void unregister_as_ext3(void)
5455 {
5456 	unregister_filesystem(&ext3_fs_type);
5457 }
5458 
5459 static inline int ext3_feature_set_ok(struct super_block *sb)
5460 {
5461 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT3_FEATURE_INCOMPAT_SUPP))
5462 		return 0;
5463 	if (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL))
5464 		return 0;
5465 	if (sb->s_flags & MS_RDONLY)
5466 		return 1;
5467 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT3_FEATURE_RO_COMPAT_SUPP))
5468 		return 0;
5469 	return 1;
5470 }
5471 #else
5472 static inline void register_as_ext3(void) { }
5473 static inline void unregister_as_ext3(void) { }
5474 static inline int ext3_feature_set_ok(struct super_block *sb) { return 0; }
5475 #endif
5476 
5477 static struct file_system_type ext4_fs_type = {
5478 	.owner		= THIS_MODULE,
5479 	.name		= "ext4",
5480 	.mount		= ext4_mount,
5481 	.kill_sb	= kill_block_super,
5482 	.fs_flags	= FS_REQUIRES_DEV,
5483 };
5484 MODULE_ALIAS_FS("ext4");
5485 
5486 static int __init ext4_init_feat_adverts(void)
5487 {
5488 	struct ext4_features *ef;
5489 	int ret = -ENOMEM;
5490 
5491 	ef = kzalloc(sizeof(struct ext4_features), GFP_KERNEL);
5492 	if (!ef)
5493 		goto out;
5494 
5495 	ef->f_kobj.kset = ext4_kset;
5496 	init_completion(&ef->f_kobj_unregister);
5497 	ret = kobject_init_and_add(&ef->f_kobj, &ext4_feat_ktype, NULL,
5498 				   "features");
5499 	if (ret) {
5500 		kfree(ef);
5501 		goto out;
5502 	}
5503 
5504 	ext4_feat = ef;
5505 	ret = 0;
5506 out:
5507 	return ret;
5508 }
5509 
5510 static void ext4_exit_feat_adverts(void)
5511 {
5512 	kobject_put(&ext4_feat->f_kobj);
5513 	wait_for_completion(&ext4_feat->f_kobj_unregister);
5514 	kfree(ext4_feat);
5515 }
5516 
5517 /* Shared across all ext4 file systems */
5518 wait_queue_head_t ext4__ioend_wq[EXT4_WQ_HASH_SZ];
5519 struct mutex ext4__aio_mutex[EXT4_WQ_HASH_SZ];
5520 
5521 static int __init ext4_init_fs(void)
5522 {
5523 	int i, err;
5524 
5525 	ext4_li_info = NULL;
5526 	mutex_init(&ext4_li_mtx);
5527 
5528 	/* Build-time check for flags consistency */
5529 	ext4_check_flag_values();
5530 
5531 	for (i = 0; i < EXT4_WQ_HASH_SZ; i++) {
5532 		mutex_init(&ext4__aio_mutex[i]);
5533 		init_waitqueue_head(&ext4__ioend_wq[i]);
5534 	}
5535 
5536 	err = ext4_init_es();
5537 	if (err)
5538 		return err;
5539 
5540 	err = ext4_init_pageio();
5541 	if (err)
5542 		goto out7;
5543 
5544 	err = ext4_init_system_zone();
5545 	if (err)
5546 		goto out6;
5547 	ext4_kset = kset_create_and_add("ext4", NULL, fs_kobj);
5548 	if (!ext4_kset) {
5549 		err = -ENOMEM;
5550 		goto out5;
5551 	}
5552 	ext4_proc_root = proc_mkdir("fs/ext4", NULL);
5553 
5554 	err = ext4_init_feat_adverts();
5555 	if (err)
5556 		goto out4;
5557 
5558 	err = ext4_init_mballoc();
5559 	if (err)
5560 		goto out2;
5561 	else
5562 		ext4_mballoc_ready = 1;
5563 	err = init_inodecache();
5564 	if (err)
5565 		goto out1;
5566 	register_as_ext3();
5567 	register_as_ext2();
5568 	err = register_filesystem(&ext4_fs_type);
5569 	if (err)
5570 		goto out;
5571 
5572 	return 0;
5573 out:
5574 	unregister_as_ext2();
5575 	unregister_as_ext3();
5576 	destroy_inodecache();
5577 out1:
5578 	ext4_mballoc_ready = 0;
5579 	ext4_exit_mballoc();
5580 out2:
5581 	ext4_exit_feat_adverts();
5582 out4:
5583 	if (ext4_proc_root)
5584 		remove_proc_entry("fs/ext4", NULL);
5585 	kset_unregister(ext4_kset);
5586 out5:
5587 	ext4_exit_system_zone();
5588 out6:
5589 	ext4_exit_pageio();
5590 out7:
5591 	ext4_exit_es();
5592 
5593 	return err;
5594 }
5595 
5596 static void __exit ext4_exit_fs(void)
5597 {
5598 	ext4_destroy_lazyinit_thread();
5599 	unregister_as_ext2();
5600 	unregister_as_ext3();
5601 	unregister_filesystem(&ext4_fs_type);
5602 	destroy_inodecache();
5603 	ext4_exit_mballoc();
5604 	ext4_exit_feat_adverts();
5605 	remove_proc_entry("fs/ext4", NULL);
5606 	kset_unregister(ext4_kset);
5607 	ext4_exit_system_zone();
5608 	ext4_exit_pageio();
5609 	ext4_exit_es();
5610 }
5611 
5612 MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
5613 MODULE_DESCRIPTION("Fourth Extended Filesystem");
5614 MODULE_LICENSE("GPL");
5615 module_init(ext4_init_fs)
5616 module_exit(ext4_exit_fs)
5617