xref: /openbmc/linux/fs/ext4/super.c (revision 6774def6)
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_remount(struct super_block *sb, int *flags, char *data);
74 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf);
75 static int ext4_unfreeze(struct super_block *sb);
76 static int ext4_freeze(struct super_block *sb);
77 static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
78 		       const char *dev_name, void *data);
79 static inline int ext2_feature_set_ok(struct super_block *sb);
80 static inline int ext3_feature_set_ok(struct super_block *sb);
81 static int ext4_feature_set_ok(struct super_block *sb, int readonly);
82 static void ext4_destroy_lazyinit_thread(void);
83 static void ext4_unregister_li_request(struct super_block *sb);
84 static void ext4_clear_request_list(void);
85 static int ext4_reserve_clusters(struct ext4_sb_info *, ext4_fsblk_t);
86 
87 #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
88 static struct file_system_type ext2_fs_type = {
89 	.owner		= THIS_MODULE,
90 	.name		= "ext2",
91 	.mount		= ext4_mount,
92 	.kill_sb	= kill_block_super,
93 	.fs_flags	= FS_REQUIRES_DEV,
94 };
95 MODULE_ALIAS_FS("ext2");
96 MODULE_ALIAS("ext2");
97 #define IS_EXT2_SB(sb) ((sb)->s_bdev->bd_holder == &ext2_fs_type)
98 #else
99 #define IS_EXT2_SB(sb) (0)
100 #endif
101 
102 
103 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
104 static struct file_system_type ext3_fs_type = {
105 	.owner		= THIS_MODULE,
106 	.name		= "ext3",
107 	.mount		= ext4_mount,
108 	.kill_sb	= kill_block_super,
109 	.fs_flags	= FS_REQUIRES_DEV,
110 };
111 MODULE_ALIAS_FS("ext3");
112 MODULE_ALIAS("ext3");
113 #define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type)
114 #else
115 #define IS_EXT3_SB(sb) (0)
116 #endif
117 
118 static int ext4_verify_csum_type(struct super_block *sb,
119 				 struct ext4_super_block *es)
120 {
121 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
122 					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
123 		return 1;
124 
125 	return es->s_checksum_type == EXT4_CRC32C_CHKSUM;
126 }
127 
128 static __le32 ext4_superblock_csum(struct super_block *sb,
129 				   struct ext4_super_block *es)
130 {
131 	struct ext4_sb_info *sbi = EXT4_SB(sb);
132 	int offset = offsetof(struct ext4_super_block, s_checksum);
133 	__u32 csum;
134 
135 	csum = ext4_chksum(sbi, ~0, (char *)es, offset);
136 
137 	return cpu_to_le32(csum);
138 }
139 
140 static int ext4_superblock_csum_verify(struct super_block *sb,
141 				       struct ext4_super_block *es)
142 {
143 	if (!ext4_has_metadata_csum(sb))
144 		return 1;
145 
146 	return es->s_checksum == ext4_superblock_csum(sb, es);
147 }
148 
149 void ext4_superblock_csum_set(struct super_block *sb)
150 {
151 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
152 
153 	if (!ext4_has_metadata_csum(sb))
154 		return;
155 
156 	es->s_checksum = ext4_superblock_csum(sb, es);
157 }
158 
159 void *ext4_kvmalloc(size_t size, gfp_t flags)
160 {
161 	void *ret;
162 
163 	ret = kmalloc(size, flags | __GFP_NOWARN);
164 	if (!ret)
165 		ret = __vmalloc(size, flags, PAGE_KERNEL);
166 	return ret;
167 }
168 
169 void *ext4_kvzalloc(size_t size, gfp_t flags)
170 {
171 	void *ret;
172 
173 	ret = kzalloc(size, flags | __GFP_NOWARN);
174 	if (!ret)
175 		ret = __vmalloc(size, flags | __GFP_ZERO, PAGE_KERNEL);
176 	return ret;
177 }
178 
179 void ext4_kvfree(void *ptr)
180 {
181 	if (is_vmalloc_addr(ptr))
182 		vfree(ptr);
183 	else
184 		kfree(ptr);
185 
186 }
187 
188 ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
189 			       struct ext4_group_desc *bg)
190 {
191 	return le32_to_cpu(bg->bg_block_bitmap_lo) |
192 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
193 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_block_bitmap_hi) << 32 : 0);
194 }
195 
196 ext4_fsblk_t ext4_inode_bitmap(struct super_block *sb,
197 			       struct ext4_group_desc *bg)
198 {
199 	return le32_to_cpu(bg->bg_inode_bitmap_lo) |
200 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
201 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_bitmap_hi) << 32 : 0);
202 }
203 
204 ext4_fsblk_t ext4_inode_table(struct super_block *sb,
205 			      struct ext4_group_desc *bg)
206 {
207 	return le32_to_cpu(bg->bg_inode_table_lo) |
208 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
209 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_table_hi) << 32 : 0);
210 }
211 
212 __u32 ext4_free_group_clusters(struct super_block *sb,
213 			       struct ext4_group_desc *bg)
214 {
215 	return le16_to_cpu(bg->bg_free_blocks_count_lo) |
216 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
217 		 (__u32)le16_to_cpu(bg->bg_free_blocks_count_hi) << 16 : 0);
218 }
219 
220 __u32 ext4_free_inodes_count(struct super_block *sb,
221 			      struct ext4_group_desc *bg)
222 {
223 	return le16_to_cpu(bg->bg_free_inodes_count_lo) |
224 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
225 		 (__u32)le16_to_cpu(bg->bg_free_inodes_count_hi) << 16 : 0);
226 }
227 
228 __u32 ext4_used_dirs_count(struct super_block *sb,
229 			      struct ext4_group_desc *bg)
230 {
231 	return le16_to_cpu(bg->bg_used_dirs_count_lo) |
232 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
233 		 (__u32)le16_to_cpu(bg->bg_used_dirs_count_hi) << 16 : 0);
234 }
235 
236 __u32 ext4_itable_unused_count(struct super_block *sb,
237 			      struct ext4_group_desc *bg)
238 {
239 	return le16_to_cpu(bg->bg_itable_unused_lo) |
240 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
241 		 (__u32)le16_to_cpu(bg->bg_itable_unused_hi) << 16 : 0);
242 }
243 
244 void ext4_block_bitmap_set(struct super_block *sb,
245 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
246 {
247 	bg->bg_block_bitmap_lo = cpu_to_le32((u32)blk);
248 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
249 		bg->bg_block_bitmap_hi = cpu_to_le32(blk >> 32);
250 }
251 
252 void ext4_inode_bitmap_set(struct super_block *sb,
253 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
254 {
255 	bg->bg_inode_bitmap_lo  = cpu_to_le32((u32)blk);
256 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
257 		bg->bg_inode_bitmap_hi = cpu_to_le32(blk >> 32);
258 }
259 
260 void ext4_inode_table_set(struct super_block *sb,
261 			  struct ext4_group_desc *bg, ext4_fsblk_t blk)
262 {
263 	bg->bg_inode_table_lo = cpu_to_le32((u32)blk);
264 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
265 		bg->bg_inode_table_hi = cpu_to_le32(blk >> 32);
266 }
267 
268 void ext4_free_group_clusters_set(struct super_block *sb,
269 				  struct ext4_group_desc *bg, __u32 count)
270 {
271 	bg->bg_free_blocks_count_lo = cpu_to_le16((__u16)count);
272 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
273 		bg->bg_free_blocks_count_hi = cpu_to_le16(count >> 16);
274 }
275 
276 void ext4_free_inodes_set(struct super_block *sb,
277 			  struct ext4_group_desc *bg, __u32 count)
278 {
279 	bg->bg_free_inodes_count_lo = cpu_to_le16((__u16)count);
280 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
281 		bg->bg_free_inodes_count_hi = cpu_to_le16(count >> 16);
282 }
283 
284 void ext4_used_dirs_set(struct super_block *sb,
285 			  struct ext4_group_desc *bg, __u32 count)
286 {
287 	bg->bg_used_dirs_count_lo = cpu_to_le16((__u16)count);
288 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
289 		bg->bg_used_dirs_count_hi = cpu_to_le16(count >> 16);
290 }
291 
292 void ext4_itable_unused_set(struct super_block *sb,
293 			  struct ext4_group_desc *bg, __u32 count)
294 {
295 	bg->bg_itable_unused_lo = cpu_to_le16((__u16)count);
296 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
297 		bg->bg_itable_unused_hi = cpu_to_le16(count >> 16);
298 }
299 
300 
301 static void __save_error_info(struct super_block *sb, const char *func,
302 			    unsigned int line)
303 {
304 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
305 
306 	EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
307 	es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
308 	es->s_last_error_time = cpu_to_le32(get_seconds());
309 	strncpy(es->s_last_error_func, func, sizeof(es->s_last_error_func));
310 	es->s_last_error_line = cpu_to_le32(line);
311 	if (!es->s_first_error_time) {
312 		es->s_first_error_time = es->s_last_error_time;
313 		strncpy(es->s_first_error_func, func,
314 			sizeof(es->s_first_error_func));
315 		es->s_first_error_line = cpu_to_le32(line);
316 		es->s_first_error_ino = es->s_last_error_ino;
317 		es->s_first_error_block = es->s_last_error_block;
318 	}
319 	/*
320 	 * Start the daily error reporting function if it hasn't been
321 	 * started already
322 	 */
323 	if (!es->s_error_count)
324 		mod_timer(&EXT4_SB(sb)->s_err_report, jiffies + 24*60*60*HZ);
325 	le32_add_cpu(&es->s_error_count, 1);
326 }
327 
328 static void save_error_info(struct super_block *sb, const char *func,
329 			    unsigned int line)
330 {
331 	__save_error_info(sb, func, line);
332 	ext4_commit_super(sb, 1);
333 }
334 
335 /*
336  * The del_gendisk() function uninitializes the disk-specific data
337  * structures, including the bdi structure, without telling anyone
338  * else.  Once this happens, any attempt to call mark_buffer_dirty()
339  * (for example, by ext4_commit_super), will cause a kernel OOPS.
340  * This is a kludge to prevent these oops until we can put in a proper
341  * hook in del_gendisk() to inform the VFS and file system layers.
342  */
343 static int block_device_ejected(struct super_block *sb)
344 {
345 	struct inode *bd_inode = sb->s_bdev->bd_inode;
346 	struct backing_dev_info *bdi = bd_inode->i_mapping->backing_dev_info;
347 
348 	return bdi->dev == NULL;
349 }
350 
351 static void ext4_journal_commit_callback(journal_t *journal, transaction_t *txn)
352 {
353 	struct super_block		*sb = journal->j_private;
354 	struct ext4_sb_info		*sbi = EXT4_SB(sb);
355 	int				error = is_journal_aborted(journal);
356 	struct ext4_journal_cb_entry	*jce;
357 
358 	BUG_ON(txn->t_state == T_FINISHED);
359 	spin_lock(&sbi->s_md_lock);
360 	while (!list_empty(&txn->t_private_list)) {
361 		jce = list_entry(txn->t_private_list.next,
362 				 struct ext4_journal_cb_entry, jce_list);
363 		list_del_init(&jce->jce_list);
364 		spin_unlock(&sbi->s_md_lock);
365 		jce->jce_func(sb, jce, error);
366 		spin_lock(&sbi->s_md_lock);
367 	}
368 	spin_unlock(&sbi->s_md_lock);
369 }
370 
371 /* Deal with the reporting of failure conditions on a filesystem such as
372  * inconsistencies detected or read IO failures.
373  *
374  * On ext2, we can store the error state of the filesystem in the
375  * superblock.  That is not possible on ext4, because we may have other
376  * write ordering constraints on the superblock which prevent us from
377  * writing it out straight away; and given that the journal is about to
378  * be aborted, we can't rely on the current, or future, transactions to
379  * write out the superblock safely.
380  *
381  * We'll just use the jbd2_journal_abort() error code to record an error in
382  * the journal instead.  On recovery, the journal will complain about
383  * that error until we've noted it down and cleared it.
384  */
385 
386 static void ext4_handle_error(struct super_block *sb)
387 {
388 	if (sb->s_flags & MS_RDONLY)
389 		return;
390 
391 	if (!test_opt(sb, ERRORS_CONT)) {
392 		journal_t *journal = EXT4_SB(sb)->s_journal;
393 
394 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
395 		if (journal)
396 			jbd2_journal_abort(journal, -EIO);
397 	}
398 	if (test_opt(sb, ERRORS_RO)) {
399 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
400 		/*
401 		 * Make sure updated value of ->s_mount_flags will be visible
402 		 * before ->s_flags update
403 		 */
404 		smp_wmb();
405 		sb->s_flags |= MS_RDONLY;
406 	}
407 	if (test_opt(sb, ERRORS_PANIC))
408 		panic("EXT4-fs (device %s): panic forced after error\n",
409 			sb->s_id);
410 }
411 
412 #define ext4_error_ratelimit(sb)					\
413 		___ratelimit(&(EXT4_SB(sb)->s_err_ratelimit_state),	\
414 			     "EXT4-fs error")
415 
416 void __ext4_error(struct super_block *sb, const char *function,
417 		  unsigned int line, const char *fmt, ...)
418 {
419 	struct va_format vaf;
420 	va_list args;
421 
422 	if (ext4_error_ratelimit(sb)) {
423 		va_start(args, fmt);
424 		vaf.fmt = fmt;
425 		vaf.va = &args;
426 		printk(KERN_CRIT
427 		       "EXT4-fs error (device %s): %s:%d: comm %s: %pV\n",
428 		       sb->s_id, function, line, current->comm, &vaf);
429 		va_end(args);
430 	}
431 	save_error_info(sb, function, line);
432 	ext4_handle_error(sb);
433 }
434 
435 void __ext4_error_inode(struct inode *inode, const char *function,
436 			unsigned int line, ext4_fsblk_t block,
437 			const char *fmt, ...)
438 {
439 	va_list args;
440 	struct va_format vaf;
441 	struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
442 
443 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
444 	es->s_last_error_block = cpu_to_le64(block);
445 	if (ext4_error_ratelimit(inode->i_sb)) {
446 		va_start(args, fmt);
447 		vaf.fmt = fmt;
448 		vaf.va = &args;
449 		if (block)
450 			printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
451 			       "inode #%lu: block %llu: comm %s: %pV\n",
452 			       inode->i_sb->s_id, function, line, inode->i_ino,
453 			       block, current->comm, &vaf);
454 		else
455 			printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
456 			       "inode #%lu: comm %s: %pV\n",
457 			       inode->i_sb->s_id, function, line, inode->i_ino,
458 			       current->comm, &vaf);
459 		va_end(args);
460 	}
461 	save_error_info(inode->i_sb, function, line);
462 	ext4_handle_error(inode->i_sb);
463 }
464 
465 void __ext4_error_file(struct file *file, const char *function,
466 		       unsigned int line, ext4_fsblk_t block,
467 		       const char *fmt, ...)
468 {
469 	va_list args;
470 	struct va_format vaf;
471 	struct ext4_super_block *es;
472 	struct inode *inode = file_inode(file);
473 	char pathname[80], *path;
474 
475 	es = EXT4_SB(inode->i_sb)->s_es;
476 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
477 	if (ext4_error_ratelimit(inode->i_sb)) {
478 		path = d_path(&(file->f_path), pathname, sizeof(pathname));
479 		if (IS_ERR(path))
480 			path = "(unknown)";
481 		va_start(args, fmt);
482 		vaf.fmt = fmt;
483 		vaf.va = &args;
484 		if (block)
485 			printk(KERN_CRIT
486 			       "EXT4-fs error (device %s): %s:%d: inode #%lu: "
487 			       "block %llu: comm %s: path %s: %pV\n",
488 			       inode->i_sb->s_id, function, line, inode->i_ino,
489 			       block, current->comm, path, &vaf);
490 		else
491 			printk(KERN_CRIT
492 			       "EXT4-fs error (device %s): %s:%d: inode #%lu: "
493 			       "comm %s: path %s: %pV\n",
494 			       inode->i_sb->s_id, function, line, inode->i_ino,
495 			       current->comm, path, &vaf);
496 		va_end(args);
497 	}
498 	save_error_info(inode->i_sb, function, line);
499 	ext4_handle_error(inode->i_sb);
500 }
501 
502 const char *ext4_decode_error(struct super_block *sb, int errno,
503 			      char nbuf[16])
504 {
505 	char *errstr = NULL;
506 
507 	switch (errno) {
508 	case -EIO:
509 		errstr = "IO failure";
510 		break;
511 	case -ENOMEM:
512 		errstr = "Out of memory";
513 		break;
514 	case -EROFS:
515 		if (!sb || (EXT4_SB(sb)->s_journal &&
516 			    EXT4_SB(sb)->s_journal->j_flags & JBD2_ABORT))
517 			errstr = "Journal has aborted";
518 		else
519 			errstr = "Readonly filesystem";
520 		break;
521 	default:
522 		/* If the caller passed in an extra buffer for unknown
523 		 * errors, textualise them now.  Else we just return
524 		 * NULL. */
525 		if (nbuf) {
526 			/* Check for truncated error codes... */
527 			if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
528 				errstr = nbuf;
529 		}
530 		break;
531 	}
532 
533 	return errstr;
534 }
535 
536 /* __ext4_std_error decodes expected errors from journaling functions
537  * automatically and invokes the appropriate error response.  */
538 
539 void __ext4_std_error(struct super_block *sb, const char *function,
540 		      unsigned int line, int errno)
541 {
542 	char nbuf[16];
543 	const char *errstr;
544 
545 	/* Special case: if the error is EROFS, and we're not already
546 	 * inside a transaction, then there's really no point in logging
547 	 * an error. */
548 	if (errno == -EROFS && journal_current_handle() == NULL &&
549 	    (sb->s_flags & MS_RDONLY))
550 		return;
551 
552 	if (ext4_error_ratelimit(sb)) {
553 		errstr = ext4_decode_error(sb, errno, nbuf);
554 		printk(KERN_CRIT "EXT4-fs error (device %s) in %s:%d: %s\n",
555 		       sb->s_id, function, line, errstr);
556 	}
557 
558 	save_error_info(sb, function, line);
559 	ext4_handle_error(sb);
560 }
561 
562 /*
563  * ext4_abort is a much stronger failure handler than ext4_error.  The
564  * abort function may be used to deal with unrecoverable failures such
565  * as journal IO errors or ENOMEM at a critical moment in log management.
566  *
567  * We unconditionally force the filesystem into an ABORT|READONLY state,
568  * unless the error response on the fs has been set to panic in which
569  * case we take the easy way out and panic immediately.
570  */
571 
572 void __ext4_abort(struct super_block *sb, const char *function,
573 		unsigned int line, const char *fmt, ...)
574 {
575 	va_list args;
576 
577 	save_error_info(sb, function, line);
578 	va_start(args, fmt);
579 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: ", sb->s_id,
580 	       function, line);
581 	vprintk(fmt, args);
582 	printk("\n");
583 	va_end(args);
584 
585 	if ((sb->s_flags & MS_RDONLY) == 0) {
586 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
587 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
588 		/*
589 		 * Make sure updated value of ->s_mount_flags will be visible
590 		 * before ->s_flags update
591 		 */
592 		smp_wmb();
593 		sb->s_flags |= MS_RDONLY;
594 		if (EXT4_SB(sb)->s_journal)
595 			jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
596 		save_error_info(sb, function, line);
597 	}
598 	if (test_opt(sb, ERRORS_PANIC))
599 		panic("EXT4-fs panic from previous error\n");
600 }
601 
602 void __ext4_msg(struct super_block *sb,
603 		const char *prefix, const char *fmt, ...)
604 {
605 	struct va_format vaf;
606 	va_list args;
607 
608 	if (!___ratelimit(&(EXT4_SB(sb)->s_msg_ratelimit_state), "EXT4-fs"))
609 		return;
610 
611 	va_start(args, fmt);
612 	vaf.fmt = fmt;
613 	vaf.va = &args;
614 	printk("%sEXT4-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
615 	va_end(args);
616 }
617 
618 void __ext4_warning(struct super_block *sb, const char *function,
619 		    unsigned int line, const char *fmt, ...)
620 {
621 	struct va_format vaf;
622 	va_list args;
623 
624 	if (!___ratelimit(&(EXT4_SB(sb)->s_warning_ratelimit_state),
625 			  "EXT4-fs warning"))
626 		return;
627 
628 	va_start(args, fmt);
629 	vaf.fmt = fmt;
630 	vaf.va = &args;
631 	printk(KERN_WARNING "EXT4-fs warning (device %s): %s:%d: %pV\n",
632 	       sb->s_id, function, line, &vaf);
633 	va_end(args);
634 }
635 
636 void __ext4_grp_locked_error(const char *function, unsigned int line,
637 			     struct super_block *sb, ext4_group_t grp,
638 			     unsigned long ino, ext4_fsblk_t block,
639 			     const char *fmt, ...)
640 __releases(bitlock)
641 __acquires(bitlock)
642 {
643 	struct va_format vaf;
644 	va_list args;
645 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
646 
647 	es->s_last_error_ino = cpu_to_le32(ino);
648 	es->s_last_error_block = cpu_to_le64(block);
649 	__save_error_info(sb, function, line);
650 
651 	if (ext4_error_ratelimit(sb)) {
652 		va_start(args, fmt);
653 		vaf.fmt = fmt;
654 		vaf.va = &args;
655 		printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: group %u, ",
656 		       sb->s_id, function, line, grp);
657 		if (ino)
658 			printk(KERN_CONT "inode %lu: ", ino);
659 		if (block)
660 			printk(KERN_CONT "block %llu:",
661 			       (unsigned long long) block);
662 		printk(KERN_CONT "%pV\n", &vaf);
663 		va_end(args);
664 	}
665 
666 	if (test_opt(sb, ERRORS_CONT)) {
667 		ext4_commit_super(sb, 0);
668 		return;
669 	}
670 
671 	ext4_unlock_group(sb, grp);
672 	ext4_handle_error(sb);
673 	/*
674 	 * We only get here in the ERRORS_RO case; relocking the group
675 	 * may be dangerous, but nothing bad will happen since the
676 	 * filesystem will have already been marked read/only and the
677 	 * journal has been aborted.  We return 1 as a hint to callers
678 	 * who might what to use the return value from
679 	 * ext4_grp_locked_error() to distinguish between the
680 	 * ERRORS_CONT and ERRORS_RO case, and perhaps return more
681 	 * aggressively from the ext4 function in question, with a
682 	 * more appropriate error code.
683 	 */
684 	ext4_lock_group(sb, grp);
685 	return;
686 }
687 
688 void ext4_update_dynamic_rev(struct super_block *sb)
689 {
690 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
691 
692 	if (le32_to_cpu(es->s_rev_level) > EXT4_GOOD_OLD_REV)
693 		return;
694 
695 	ext4_warning(sb,
696 		     "updating to rev %d because of new feature flag, "
697 		     "running e2fsck is recommended",
698 		     EXT4_DYNAMIC_REV);
699 
700 	es->s_first_ino = cpu_to_le32(EXT4_GOOD_OLD_FIRST_INO);
701 	es->s_inode_size = cpu_to_le16(EXT4_GOOD_OLD_INODE_SIZE);
702 	es->s_rev_level = cpu_to_le32(EXT4_DYNAMIC_REV);
703 	/* leave es->s_feature_*compat flags alone */
704 	/* es->s_uuid will be set by e2fsck if empty */
705 
706 	/*
707 	 * The rest of the superblock fields should be zero, and if not it
708 	 * means they are likely already in use, so leave them alone.  We
709 	 * can leave it up to e2fsck to clean up any inconsistencies there.
710 	 */
711 }
712 
713 /*
714  * Open the external journal device
715  */
716 static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb)
717 {
718 	struct block_device *bdev;
719 	char b[BDEVNAME_SIZE];
720 
721 	bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb);
722 	if (IS_ERR(bdev))
723 		goto fail;
724 	return bdev;
725 
726 fail:
727 	ext4_msg(sb, KERN_ERR, "failed to open journal device %s: %ld",
728 			__bdevname(dev, b), PTR_ERR(bdev));
729 	return NULL;
730 }
731 
732 /*
733  * Release the journal device
734  */
735 static void ext4_blkdev_put(struct block_device *bdev)
736 {
737 	blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
738 }
739 
740 static void ext4_blkdev_remove(struct ext4_sb_info *sbi)
741 {
742 	struct block_device *bdev;
743 	bdev = sbi->journal_bdev;
744 	if (bdev) {
745 		ext4_blkdev_put(bdev);
746 		sbi->journal_bdev = NULL;
747 	}
748 }
749 
750 static inline struct inode *orphan_list_entry(struct list_head *l)
751 {
752 	return &list_entry(l, struct ext4_inode_info, i_orphan)->vfs_inode;
753 }
754 
755 static void dump_orphan_list(struct super_block *sb, struct ext4_sb_info *sbi)
756 {
757 	struct list_head *l;
758 
759 	ext4_msg(sb, KERN_ERR, "sb orphan head is %d",
760 		 le32_to_cpu(sbi->s_es->s_last_orphan));
761 
762 	printk(KERN_ERR "sb_info orphan list:\n");
763 	list_for_each(l, &sbi->s_orphan) {
764 		struct inode *inode = orphan_list_entry(l);
765 		printk(KERN_ERR "  "
766 		       "inode %s:%lu at %p: mode %o, nlink %d, next %d\n",
767 		       inode->i_sb->s_id, inode->i_ino, inode,
768 		       inode->i_mode, inode->i_nlink,
769 		       NEXT_ORPHAN(inode));
770 	}
771 }
772 
773 static void ext4_put_super(struct super_block *sb)
774 {
775 	struct ext4_sb_info *sbi = EXT4_SB(sb);
776 	struct ext4_super_block *es = sbi->s_es;
777 	int i, err;
778 
779 	ext4_unregister_li_request(sb);
780 	dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
781 
782 	flush_workqueue(sbi->rsv_conversion_wq);
783 	destroy_workqueue(sbi->rsv_conversion_wq);
784 
785 	if (sbi->s_journal) {
786 		err = jbd2_journal_destroy(sbi->s_journal);
787 		sbi->s_journal = NULL;
788 		if (err < 0)
789 			ext4_abort(sb, "Couldn't clean up the journal");
790 	}
791 
792 	ext4_es_unregister_shrinker(sbi);
793 	del_timer_sync(&sbi->s_err_report);
794 	ext4_release_system_zone(sb);
795 	ext4_mb_release(sb);
796 	ext4_ext_release(sb);
797 	ext4_xattr_put_super(sb);
798 
799 	if (!(sb->s_flags & MS_RDONLY)) {
800 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
801 		es->s_state = cpu_to_le16(sbi->s_mount_state);
802 	}
803 	if (!(sb->s_flags & MS_RDONLY))
804 		ext4_commit_super(sb, 1);
805 
806 	if (sbi->s_proc) {
807 		remove_proc_entry("options", sbi->s_proc);
808 		remove_proc_entry(sb->s_id, ext4_proc_root);
809 	}
810 	kobject_del(&sbi->s_kobj);
811 
812 	for (i = 0; i < sbi->s_gdb_count; i++)
813 		brelse(sbi->s_group_desc[i]);
814 	ext4_kvfree(sbi->s_group_desc);
815 	ext4_kvfree(sbi->s_flex_groups);
816 	percpu_counter_destroy(&sbi->s_freeclusters_counter);
817 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
818 	percpu_counter_destroy(&sbi->s_dirs_counter);
819 	percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
820 	brelse(sbi->s_sbh);
821 #ifdef CONFIG_QUOTA
822 	for (i = 0; i < EXT4_MAXQUOTAS; i++)
823 		kfree(sbi->s_qf_names[i]);
824 #endif
825 
826 	/* Debugging code just in case the in-memory inode orphan list
827 	 * isn't empty.  The on-disk one can be non-empty if we've
828 	 * detected an error and taken the fs readonly, but the
829 	 * in-memory list had better be clean by this point. */
830 	if (!list_empty(&sbi->s_orphan))
831 		dump_orphan_list(sb, sbi);
832 	J_ASSERT(list_empty(&sbi->s_orphan));
833 
834 	invalidate_bdev(sb->s_bdev);
835 	if (sbi->journal_bdev && sbi->journal_bdev != sb->s_bdev) {
836 		/*
837 		 * Invalidate the journal device's buffers.  We don't want them
838 		 * floating about in memory - the physical journal device may
839 		 * hotswapped, and it breaks the `ro-after' testing code.
840 		 */
841 		sync_blockdev(sbi->journal_bdev);
842 		invalidate_bdev(sbi->journal_bdev);
843 		ext4_blkdev_remove(sbi);
844 	}
845 	if (sbi->s_mb_cache) {
846 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
847 		sbi->s_mb_cache = NULL;
848 	}
849 	if (sbi->s_mmp_tsk)
850 		kthread_stop(sbi->s_mmp_tsk);
851 	sb->s_fs_info = NULL;
852 	/*
853 	 * Now that we are completely done shutting down the
854 	 * superblock, we need to actually destroy the kobject.
855 	 */
856 	kobject_put(&sbi->s_kobj);
857 	wait_for_completion(&sbi->s_kobj_unregister);
858 	if (sbi->s_chksum_driver)
859 		crypto_free_shash(sbi->s_chksum_driver);
860 	kfree(sbi->s_blockgroup_lock);
861 	kfree(sbi);
862 }
863 
864 static struct kmem_cache *ext4_inode_cachep;
865 
866 /*
867  * Called inside transaction, so use GFP_NOFS
868  */
869 static struct inode *ext4_alloc_inode(struct super_block *sb)
870 {
871 	struct ext4_inode_info *ei;
872 
873 	ei = kmem_cache_alloc(ext4_inode_cachep, GFP_NOFS);
874 	if (!ei)
875 		return NULL;
876 
877 	ei->vfs_inode.i_version = 1;
878 	spin_lock_init(&ei->i_raw_lock);
879 	INIT_LIST_HEAD(&ei->i_prealloc_list);
880 	spin_lock_init(&ei->i_prealloc_lock);
881 	ext4_es_init_tree(&ei->i_es_tree);
882 	rwlock_init(&ei->i_es_lock);
883 	INIT_LIST_HEAD(&ei->i_es_lru);
884 	ei->i_es_all_nr = 0;
885 	ei->i_es_lru_nr = 0;
886 	ei->i_touch_when = 0;
887 	ei->i_reserved_data_blocks = 0;
888 	ei->i_reserved_meta_blocks = 0;
889 	ei->i_allocated_meta_blocks = 0;
890 	ei->i_da_metadata_calc_len = 0;
891 	ei->i_da_metadata_calc_last_lblock = 0;
892 	spin_lock_init(&(ei->i_block_reservation_lock));
893 #ifdef CONFIG_QUOTA
894 	ei->i_reserved_quota = 0;
895 #endif
896 	ei->jinode = NULL;
897 	INIT_LIST_HEAD(&ei->i_rsv_conversion_list);
898 	spin_lock_init(&ei->i_completed_io_lock);
899 	ei->i_sync_tid = 0;
900 	ei->i_datasync_tid = 0;
901 	atomic_set(&ei->i_ioend_count, 0);
902 	atomic_set(&ei->i_unwritten, 0);
903 	INIT_WORK(&ei->i_rsv_conversion_work, ext4_end_io_rsv_work);
904 
905 	return &ei->vfs_inode;
906 }
907 
908 static int ext4_drop_inode(struct inode *inode)
909 {
910 	int drop = generic_drop_inode(inode);
911 
912 	trace_ext4_drop_inode(inode, drop);
913 	return drop;
914 }
915 
916 static void ext4_i_callback(struct rcu_head *head)
917 {
918 	struct inode *inode = container_of(head, struct inode, i_rcu);
919 	kmem_cache_free(ext4_inode_cachep, EXT4_I(inode));
920 }
921 
922 static void ext4_destroy_inode(struct inode *inode)
923 {
924 	if (!list_empty(&(EXT4_I(inode)->i_orphan))) {
925 		ext4_msg(inode->i_sb, KERN_ERR,
926 			 "Inode %lu (%p): orphan list check failed!",
927 			 inode->i_ino, EXT4_I(inode));
928 		print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 16, 4,
929 				EXT4_I(inode), sizeof(struct ext4_inode_info),
930 				true);
931 		dump_stack();
932 	}
933 	call_rcu(&inode->i_rcu, ext4_i_callback);
934 }
935 
936 static void init_once(void *foo)
937 {
938 	struct ext4_inode_info *ei = (struct ext4_inode_info *) foo;
939 
940 	INIT_LIST_HEAD(&ei->i_orphan);
941 	init_rwsem(&ei->xattr_sem);
942 	init_rwsem(&ei->i_data_sem);
943 	inode_init_once(&ei->vfs_inode);
944 }
945 
946 static int __init init_inodecache(void)
947 {
948 	ext4_inode_cachep = kmem_cache_create("ext4_inode_cache",
949 					     sizeof(struct ext4_inode_info),
950 					     0, (SLAB_RECLAIM_ACCOUNT|
951 						SLAB_MEM_SPREAD),
952 					     init_once);
953 	if (ext4_inode_cachep == NULL)
954 		return -ENOMEM;
955 	return 0;
956 }
957 
958 static void destroy_inodecache(void)
959 {
960 	/*
961 	 * Make sure all delayed rcu free inodes are flushed before we
962 	 * destroy cache.
963 	 */
964 	rcu_barrier();
965 	kmem_cache_destroy(ext4_inode_cachep);
966 }
967 
968 void ext4_clear_inode(struct inode *inode)
969 {
970 	invalidate_inode_buffers(inode);
971 	clear_inode(inode);
972 	dquot_drop(inode);
973 	ext4_discard_preallocations(inode);
974 	ext4_es_remove_extent(inode, 0, EXT_MAX_BLOCKS);
975 	ext4_es_lru_del(inode);
976 	if (EXT4_I(inode)->jinode) {
977 		jbd2_journal_release_jbd_inode(EXT4_JOURNAL(inode),
978 					       EXT4_I(inode)->jinode);
979 		jbd2_free_inode(EXT4_I(inode)->jinode);
980 		EXT4_I(inode)->jinode = NULL;
981 	}
982 }
983 
984 static struct inode *ext4_nfs_get_inode(struct super_block *sb,
985 					u64 ino, u32 generation)
986 {
987 	struct inode *inode;
988 
989 	if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
990 		return ERR_PTR(-ESTALE);
991 	if (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
992 		return ERR_PTR(-ESTALE);
993 
994 	/* iget isn't really right if the inode is currently unallocated!!
995 	 *
996 	 * ext4_read_inode will return a bad_inode if the inode had been
997 	 * deleted, so we should be safe.
998 	 *
999 	 * Currently we don't know the generation for parent directory, so
1000 	 * a generation of 0 means "accept any"
1001 	 */
1002 	inode = ext4_iget_normal(sb, ino);
1003 	if (IS_ERR(inode))
1004 		return ERR_CAST(inode);
1005 	if (generation && inode->i_generation != generation) {
1006 		iput(inode);
1007 		return ERR_PTR(-ESTALE);
1008 	}
1009 
1010 	return inode;
1011 }
1012 
1013 static struct dentry *ext4_fh_to_dentry(struct super_block *sb, struct fid *fid,
1014 					int fh_len, int fh_type)
1015 {
1016 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
1017 				    ext4_nfs_get_inode);
1018 }
1019 
1020 static struct dentry *ext4_fh_to_parent(struct super_block *sb, struct fid *fid,
1021 					int fh_len, int fh_type)
1022 {
1023 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
1024 				    ext4_nfs_get_inode);
1025 }
1026 
1027 /*
1028  * Try to release metadata pages (indirect blocks, directories) which are
1029  * mapped via the block device.  Since these pages could have journal heads
1030  * which would prevent try_to_free_buffers() from freeing them, we must use
1031  * jbd2 layer's try_to_free_buffers() function to release them.
1032  */
1033 static int bdev_try_to_free_page(struct super_block *sb, struct page *page,
1034 				 gfp_t wait)
1035 {
1036 	journal_t *journal = EXT4_SB(sb)->s_journal;
1037 
1038 	WARN_ON(PageChecked(page));
1039 	if (!page_has_buffers(page))
1040 		return 0;
1041 	if (journal)
1042 		return jbd2_journal_try_to_free_buffers(journal, page,
1043 							wait & ~__GFP_WAIT);
1044 	return try_to_free_buffers(page);
1045 }
1046 
1047 #ifdef CONFIG_QUOTA
1048 #define QTYPE2NAME(t) ((t) == USRQUOTA ? "user" : "group")
1049 #define QTYPE2MOPT(on, t) ((t) == USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
1050 
1051 static int ext4_write_dquot(struct dquot *dquot);
1052 static int ext4_acquire_dquot(struct dquot *dquot);
1053 static int ext4_release_dquot(struct dquot *dquot);
1054 static int ext4_mark_dquot_dirty(struct dquot *dquot);
1055 static int ext4_write_info(struct super_block *sb, int type);
1056 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
1057 			 struct path *path);
1058 static int ext4_quota_on_sysfile(struct super_block *sb, int type,
1059 				 int format_id);
1060 static int ext4_quota_off(struct super_block *sb, int type);
1061 static int ext4_quota_off_sysfile(struct super_block *sb, int type);
1062 static int ext4_quota_on_mount(struct super_block *sb, int type);
1063 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
1064 			       size_t len, loff_t off);
1065 static ssize_t ext4_quota_write(struct super_block *sb, int type,
1066 				const char *data, size_t len, loff_t off);
1067 static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
1068 			     unsigned int flags);
1069 static int ext4_enable_quotas(struct super_block *sb);
1070 
1071 static const struct dquot_operations ext4_quota_operations = {
1072 	.get_reserved_space = ext4_get_reserved_space,
1073 	.write_dquot	= ext4_write_dquot,
1074 	.acquire_dquot	= ext4_acquire_dquot,
1075 	.release_dquot	= ext4_release_dquot,
1076 	.mark_dirty	= ext4_mark_dquot_dirty,
1077 	.write_info	= ext4_write_info,
1078 	.alloc_dquot	= dquot_alloc,
1079 	.destroy_dquot	= dquot_destroy,
1080 };
1081 
1082 static const struct quotactl_ops ext4_qctl_operations = {
1083 	.quota_on	= ext4_quota_on,
1084 	.quota_off	= ext4_quota_off,
1085 	.quota_sync	= dquot_quota_sync,
1086 	.get_info	= dquot_get_dqinfo,
1087 	.set_info	= dquot_set_dqinfo,
1088 	.get_dqblk	= dquot_get_dqblk,
1089 	.set_dqblk	= dquot_set_dqblk
1090 };
1091 
1092 static const struct quotactl_ops ext4_qctl_sysfile_operations = {
1093 	.quota_on_meta	= ext4_quota_on_sysfile,
1094 	.quota_off	= ext4_quota_off_sysfile,
1095 	.quota_sync	= dquot_quota_sync,
1096 	.get_info	= dquot_get_dqinfo,
1097 	.set_info	= dquot_set_dqinfo,
1098 	.get_dqblk	= dquot_get_dqblk,
1099 	.set_dqblk	= dquot_set_dqblk
1100 };
1101 #endif
1102 
1103 static const struct super_operations ext4_sops = {
1104 	.alloc_inode	= ext4_alloc_inode,
1105 	.destroy_inode	= ext4_destroy_inode,
1106 	.write_inode	= ext4_write_inode,
1107 	.dirty_inode	= ext4_dirty_inode,
1108 	.drop_inode	= ext4_drop_inode,
1109 	.evict_inode	= ext4_evict_inode,
1110 	.put_super	= ext4_put_super,
1111 	.sync_fs	= ext4_sync_fs,
1112 	.freeze_fs	= ext4_freeze,
1113 	.unfreeze_fs	= ext4_unfreeze,
1114 	.statfs		= ext4_statfs,
1115 	.remount_fs	= ext4_remount,
1116 	.show_options	= ext4_show_options,
1117 #ifdef CONFIG_QUOTA
1118 	.quota_read	= ext4_quota_read,
1119 	.quota_write	= ext4_quota_write,
1120 #endif
1121 	.bdev_try_to_free_page = bdev_try_to_free_page,
1122 };
1123 
1124 static const struct export_operations ext4_export_ops = {
1125 	.fh_to_dentry = ext4_fh_to_dentry,
1126 	.fh_to_parent = ext4_fh_to_parent,
1127 	.get_parent = ext4_get_parent,
1128 };
1129 
1130 enum {
1131 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
1132 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
1133 	Opt_nouid32, Opt_debug, Opt_removed,
1134 	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
1135 	Opt_auto_da_alloc, Opt_noauto_da_alloc, Opt_noload,
1136 	Opt_commit, Opt_min_batch_time, Opt_max_batch_time, Opt_journal_dev,
1137 	Opt_journal_path, Opt_journal_checksum, Opt_journal_async_commit,
1138 	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
1139 	Opt_data_err_abort, Opt_data_err_ignore,
1140 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
1141 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
1142 	Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err,
1143 	Opt_usrquota, Opt_grpquota, Opt_i_version,
1144 	Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_mblk_io_submit,
1145 	Opt_nomblk_io_submit, Opt_block_validity, Opt_noblock_validity,
1146 	Opt_inode_readahead_blks, Opt_journal_ioprio,
1147 	Opt_dioread_nolock, Opt_dioread_lock,
1148 	Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
1149 	Opt_max_dir_size_kb,
1150 };
1151 
1152 static const match_table_t tokens = {
1153 	{Opt_bsd_df, "bsddf"},
1154 	{Opt_minix_df, "minixdf"},
1155 	{Opt_grpid, "grpid"},
1156 	{Opt_grpid, "bsdgroups"},
1157 	{Opt_nogrpid, "nogrpid"},
1158 	{Opt_nogrpid, "sysvgroups"},
1159 	{Opt_resgid, "resgid=%u"},
1160 	{Opt_resuid, "resuid=%u"},
1161 	{Opt_sb, "sb=%u"},
1162 	{Opt_err_cont, "errors=continue"},
1163 	{Opt_err_panic, "errors=panic"},
1164 	{Opt_err_ro, "errors=remount-ro"},
1165 	{Opt_nouid32, "nouid32"},
1166 	{Opt_debug, "debug"},
1167 	{Opt_removed, "oldalloc"},
1168 	{Opt_removed, "orlov"},
1169 	{Opt_user_xattr, "user_xattr"},
1170 	{Opt_nouser_xattr, "nouser_xattr"},
1171 	{Opt_acl, "acl"},
1172 	{Opt_noacl, "noacl"},
1173 	{Opt_noload, "norecovery"},
1174 	{Opt_noload, "noload"},
1175 	{Opt_removed, "nobh"},
1176 	{Opt_removed, "bh"},
1177 	{Opt_commit, "commit=%u"},
1178 	{Opt_min_batch_time, "min_batch_time=%u"},
1179 	{Opt_max_batch_time, "max_batch_time=%u"},
1180 	{Opt_journal_dev, "journal_dev=%u"},
1181 	{Opt_journal_path, "journal_path=%s"},
1182 	{Opt_journal_checksum, "journal_checksum"},
1183 	{Opt_journal_async_commit, "journal_async_commit"},
1184 	{Opt_abort, "abort"},
1185 	{Opt_data_journal, "data=journal"},
1186 	{Opt_data_ordered, "data=ordered"},
1187 	{Opt_data_writeback, "data=writeback"},
1188 	{Opt_data_err_abort, "data_err=abort"},
1189 	{Opt_data_err_ignore, "data_err=ignore"},
1190 	{Opt_offusrjquota, "usrjquota="},
1191 	{Opt_usrjquota, "usrjquota=%s"},
1192 	{Opt_offgrpjquota, "grpjquota="},
1193 	{Opt_grpjquota, "grpjquota=%s"},
1194 	{Opt_jqfmt_vfsold, "jqfmt=vfsold"},
1195 	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
1196 	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
1197 	{Opt_grpquota, "grpquota"},
1198 	{Opt_noquota, "noquota"},
1199 	{Opt_quota, "quota"},
1200 	{Opt_usrquota, "usrquota"},
1201 	{Opt_barrier, "barrier=%u"},
1202 	{Opt_barrier, "barrier"},
1203 	{Opt_nobarrier, "nobarrier"},
1204 	{Opt_i_version, "i_version"},
1205 	{Opt_stripe, "stripe=%u"},
1206 	{Opt_delalloc, "delalloc"},
1207 	{Opt_nodelalloc, "nodelalloc"},
1208 	{Opt_removed, "mblk_io_submit"},
1209 	{Opt_removed, "nomblk_io_submit"},
1210 	{Opt_block_validity, "block_validity"},
1211 	{Opt_noblock_validity, "noblock_validity"},
1212 	{Opt_inode_readahead_blks, "inode_readahead_blks=%u"},
1213 	{Opt_journal_ioprio, "journal_ioprio=%u"},
1214 	{Opt_auto_da_alloc, "auto_da_alloc=%u"},
1215 	{Opt_auto_da_alloc, "auto_da_alloc"},
1216 	{Opt_noauto_da_alloc, "noauto_da_alloc"},
1217 	{Opt_dioread_nolock, "dioread_nolock"},
1218 	{Opt_dioread_lock, "dioread_lock"},
1219 	{Opt_discard, "discard"},
1220 	{Opt_nodiscard, "nodiscard"},
1221 	{Opt_init_itable, "init_itable=%u"},
1222 	{Opt_init_itable, "init_itable"},
1223 	{Opt_noinit_itable, "noinit_itable"},
1224 	{Opt_max_dir_size_kb, "max_dir_size_kb=%u"},
1225 	{Opt_removed, "check=none"},	/* mount option from ext2/3 */
1226 	{Opt_removed, "nocheck"},	/* mount option from ext2/3 */
1227 	{Opt_removed, "reservation"},	/* mount option from ext2/3 */
1228 	{Opt_removed, "noreservation"}, /* mount option from ext2/3 */
1229 	{Opt_removed, "journal=%u"},	/* mount option from ext2/3 */
1230 	{Opt_err, NULL},
1231 };
1232 
1233 static ext4_fsblk_t get_sb_block(void **data)
1234 {
1235 	ext4_fsblk_t	sb_block;
1236 	char		*options = (char *) *data;
1237 
1238 	if (!options || strncmp(options, "sb=", 3) != 0)
1239 		return 1;	/* Default location */
1240 
1241 	options += 3;
1242 	/* TODO: use simple_strtoll with >32bit ext4 */
1243 	sb_block = simple_strtoul(options, &options, 0);
1244 	if (*options && *options != ',') {
1245 		printk(KERN_ERR "EXT4-fs: Invalid sb specification: %s\n",
1246 		       (char *) *data);
1247 		return 1;
1248 	}
1249 	if (*options == ',')
1250 		options++;
1251 	*data = (void *) options;
1252 
1253 	return sb_block;
1254 }
1255 
1256 #define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))
1257 static char deprecated_msg[] = "Mount option \"%s\" will be removed by %s\n"
1258 	"Contact linux-ext4@vger.kernel.org if you think we should keep it.\n";
1259 
1260 #ifdef CONFIG_QUOTA
1261 static int set_qf_name(struct super_block *sb, int qtype, substring_t *args)
1262 {
1263 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1264 	char *qname;
1265 	int ret = -1;
1266 
1267 	if (sb_any_quota_loaded(sb) &&
1268 		!sbi->s_qf_names[qtype]) {
1269 		ext4_msg(sb, KERN_ERR,
1270 			"Cannot change journaled "
1271 			"quota options when quota turned on");
1272 		return -1;
1273 	}
1274 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA)) {
1275 		ext4_msg(sb, KERN_ERR, "Cannot set journaled quota options "
1276 			 "when QUOTA feature is enabled");
1277 		return -1;
1278 	}
1279 	qname = match_strdup(args);
1280 	if (!qname) {
1281 		ext4_msg(sb, KERN_ERR,
1282 			"Not enough memory for storing quotafile name");
1283 		return -1;
1284 	}
1285 	if (sbi->s_qf_names[qtype]) {
1286 		if (strcmp(sbi->s_qf_names[qtype], qname) == 0)
1287 			ret = 1;
1288 		else
1289 			ext4_msg(sb, KERN_ERR,
1290 				 "%s quota file already specified",
1291 				 QTYPE2NAME(qtype));
1292 		goto errout;
1293 	}
1294 	if (strchr(qname, '/')) {
1295 		ext4_msg(sb, KERN_ERR,
1296 			"quotafile must be on filesystem root");
1297 		goto errout;
1298 	}
1299 	sbi->s_qf_names[qtype] = qname;
1300 	set_opt(sb, QUOTA);
1301 	return 1;
1302 errout:
1303 	kfree(qname);
1304 	return ret;
1305 }
1306 
1307 static int clear_qf_name(struct super_block *sb, int qtype)
1308 {
1309 
1310 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1311 
1312 	if (sb_any_quota_loaded(sb) &&
1313 		sbi->s_qf_names[qtype]) {
1314 		ext4_msg(sb, KERN_ERR, "Cannot change journaled quota options"
1315 			" when quota turned on");
1316 		return -1;
1317 	}
1318 	kfree(sbi->s_qf_names[qtype]);
1319 	sbi->s_qf_names[qtype] = NULL;
1320 	return 1;
1321 }
1322 #endif
1323 
1324 #define MOPT_SET	0x0001
1325 #define MOPT_CLEAR	0x0002
1326 #define MOPT_NOSUPPORT	0x0004
1327 #define MOPT_EXPLICIT	0x0008
1328 #define MOPT_CLEAR_ERR	0x0010
1329 #define MOPT_GTE0	0x0020
1330 #ifdef CONFIG_QUOTA
1331 #define MOPT_Q		0
1332 #define MOPT_QFMT	0x0040
1333 #else
1334 #define MOPT_Q		MOPT_NOSUPPORT
1335 #define MOPT_QFMT	MOPT_NOSUPPORT
1336 #endif
1337 #define MOPT_DATAJ	0x0080
1338 #define MOPT_NO_EXT2	0x0100
1339 #define MOPT_NO_EXT3	0x0200
1340 #define MOPT_EXT4_ONLY	(MOPT_NO_EXT2 | MOPT_NO_EXT3)
1341 #define MOPT_STRING	0x0400
1342 
1343 static const struct mount_opts {
1344 	int	token;
1345 	int	mount_opt;
1346 	int	flags;
1347 } ext4_mount_opts[] = {
1348 	{Opt_minix_df, EXT4_MOUNT_MINIX_DF, MOPT_SET},
1349 	{Opt_bsd_df, EXT4_MOUNT_MINIX_DF, MOPT_CLEAR},
1350 	{Opt_grpid, EXT4_MOUNT_GRPID, MOPT_SET},
1351 	{Opt_nogrpid, EXT4_MOUNT_GRPID, MOPT_CLEAR},
1352 	{Opt_block_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_SET},
1353 	{Opt_noblock_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_CLEAR},
1354 	{Opt_dioread_nolock, EXT4_MOUNT_DIOREAD_NOLOCK,
1355 	 MOPT_EXT4_ONLY | MOPT_SET},
1356 	{Opt_dioread_lock, EXT4_MOUNT_DIOREAD_NOLOCK,
1357 	 MOPT_EXT4_ONLY | MOPT_CLEAR},
1358 	{Opt_discard, EXT4_MOUNT_DISCARD, MOPT_SET},
1359 	{Opt_nodiscard, EXT4_MOUNT_DISCARD, MOPT_CLEAR},
1360 	{Opt_delalloc, EXT4_MOUNT_DELALLOC,
1361 	 MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
1362 	{Opt_nodelalloc, EXT4_MOUNT_DELALLOC,
1363 	 MOPT_EXT4_ONLY | MOPT_CLEAR},
1364 	{Opt_journal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,
1365 	 MOPT_EXT4_ONLY | MOPT_SET},
1366 	{Opt_journal_async_commit, (EXT4_MOUNT_JOURNAL_ASYNC_COMMIT |
1367 				    EXT4_MOUNT_JOURNAL_CHECKSUM),
1368 	 MOPT_EXT4_ONLY | MOPT_SET},
1369 	{Opt_noload, EXT4_MOUNT_NOLOAD, MOPT_NO_EXT2 | MOPT_SET},
1370 	{Opt_err_panic, EXT4_MOUNT_ERRORS_PANIC, MOPT_SET | MOPT_CLEAR_ERR},
1371 	{Opt_err_ro, EXT4_MOUNT_ERRORS_RO, MOPT_SET | MOPT_CLEAR_ERR},
1372 	{Opt_err_cont, EXT4_MOUNT_ERRORS_CONT, MOPT_SET | MOPT_CLEAR_ERR},
1373 	{Opt_data_err_abort, EXT4_MOUNT_DATA_ERR_ABORT,
1374 	 MOPT_NO_EXT2 | MOPT_SET},
1375 	{Opt_data_err_ignore, EXT4_MOUNT_DATA_ERR_ABORT,
1376 	 MOPT_NO_EXT2 | MOPT_CLEAR},
1377 	{Opt_barrier, EXT4_MOUNT_BARRIER, MOPT_SET},
1378 	{Opt_nobarrier, EXT4_MOUNT_BARRIER, MOPT_CLEAR},
1379 	{Opt_noauto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_SET},
1380 	{Opt_auto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_CLEAR},
1381 	{Opt_noinit_itable, EXT4_MOUNT_INIT_INODE_TABLE, MOPT_CLEAR},
1382 	{Opt_commit, 0, MOPT_GTE0},
1383 	{Opt_max_batch_time, 0, MOPT_GTE0},
1384 	{Opt_min_batch_time, 0, MOPT_GTE0},
1385 	{Opt_inode_readahead_blks, 0, MOPT_GTE0},
1386 	{Opt_init_itable, 0, MOPT_GTE0},
1387 	{Opt_stripe, 0, MOPT_GTE0},
1388 	{Opt_resuid, 0, MOPT_GTE0},
1389 	{Opt_resgid, 0, MOPT_GTE0},
1390 	{Opt_journal_dev, 0, MOPT_GTE0},
1391 	{Opt_journal_path, 0, MOPT_STRING},
1392 	{Opt_journal_ioprio, 0, MOPT_GTE0},
1393 	{Opt_data_journal, EXT4_MOUNT_JOURNAL_DATA, MOPT_NO_EXT2 | MOPT_DATAJ},
1394 	{Opt_data_ordered, EXT4_MOUNT_ORDERED_DATA, MOPT_NO_EXT2 | MOPT_DATAJ},
1395 	{Opt_data_writeback, EXT4_MOUNT_WRITEBACK_DATA,
1396 	 MOPT_NO_EXT2 | MOPT_DATAJ},
1397 	{Opt_user_xattr, EXT4_MOUNT_XATTR_USER, MOPT_SET},
1398 	{Opt_nouser_xattr, EXT4_MOUNT_XATTR_USER, MOPT_CLEAR},
1399 #ifdef CONFIG_EXT4_FS_POSIX_ACL
1400 	{Opt_acl, EXT4_MOUNT_POSIX_ACL, MOPT_SET},
1401 	{Opt_noacl, EXT4_MOUNT_POSIX_ACL, MOPT_CLEAR},
1402 #else
1403 	{Opt_acl, 0, MOPT_NOSUPPORT},
1404 	{Opt_noacl, 0, MOPT_NOSUPPORT},
1405 #endif
1406 	{Opt_nouid32, EXT4_MOUNT_NO_UID32, MOPT_SET},
1407 	{Opt_debug, EXT4_MOUNT_DEBUG, MOPT_SET},
1408 	{Opt_quota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA, MOPT_SET | MOPT_Q},
1409 	{Opt_usrquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA,
1410 							MOPT_SET | MOPT_Q},
1411 	{Opt_grpquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_GRPQUOTA,
1412 							MOPT_SET | MOPT_Q},
1413 	{Opt_noquota, (EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA |
1414 		       EXT4_MOUNT_GRPQUOTA), MOPT_CLEAR | MOPT_Q},
1415 	{Opt_usrjquota, 0, MOPT_Q},
1416 	{Opt_grpjquota, 0, MOPT_Q},
1417 	{Opt_offusrjquota, 0, MOPT_Q},
1418 	{Opt_offgrpjquota, 0, MOPT_Q},
1419 	{Opt_jqfmt_vfsold, QFMT_VFS_OLD, MOPT_QFMT},
1420 	{Opt_jqfmt_vfsv0, QFMT_VFS_V0, MOPT_QFMT},
1421 	{Opt_jqfmt_vfsv1, QFMT_VFS_V1, MOPT_QFMT},
1422 	{Opt_max_dir_size_kb, 0, MOPT_GTE0},
1423 	{Opt_err, 0, 0}
1424 };
1425 
1426 static int handle_mount_opt(struct super_block *sb, char *opt, int token,
1427 			    substring_t *args, unsigned long *journal_devnum,
1428 			    unsigned int *journal_ioprio, int is_remount)
1429 {
1430 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1431 	const struct mount_opts *m;
1432 	kuid_t uid;
1433 	kgid_t gid;
1434 	int arg = 0;
1435 
1436 #ifdef CONFIG_QUOTA
1437 	if (token == Opt_usrjquota)
1438 		return set_qf_name(sb, USRQUOTA, &args[0]);
1439 	else if (token == Opt_grpjquota)
1440 		return set_qf_name(sb, GRPQUOTA, &args[0]);
1441 	else if (token == Opt_offusrjquota)
1442 		return clear_qf_name(sb, USRQUOTA);
1443 	else if (token == Opt_offgrpjquota)
1444 		return clear_qf_name(sb, GRPQUOTA);
1445 #endif
1446 	switch (token) {
1447 	case Opt_noacl:
1448 	case Opt_nouser_xattr:
1449 		ext4_msg(sb, KERN_WARNING, deprecated_msg, opt, "3.5");
1450 		break;
1451 	case Opt_sb:
1452 		return 1;	/* handled by get_sb_block() */
1453 	case Opt_removed:
1454 		ext4_msg(sb, KERN_WARNING, "Ignoring removed %s option", opt);
1455 		return 1;
1456 	case Opt_abort:
1457 		sbi->s_mount_flags |= EXT4_MF_FS_ABORTED;
1458 		return 1;
1459 	case Opt_i_version:
1460 		sb->s_flags |= MS_I_VERSION;
1461 		return 1;
1462 	}
1463 
1464 	for (m = ext4_mount_opts; m->token != Opt_err; m++)
1465 		if (token == m->token)
1466 			break;
1467 
1468 	if (m->token == Opt_err) {
1469 		ext4_msg(sb, KERN_ERR, "Unrecognized mount option \"%s\" "
1470 			 "or missing value", opt);
1471 		return -1;
1472 	}
1473 
1474 	if ((m->flags & MOPT_NO_EXT2) && IS_EXT2_SB(sb)) {
1475 		ext4_msg(sb, KERN_ERR,
1476 			 "Mount option \"%s\" incompatible with ext2", opt);
1477 		return -1;
1478 	}
1479 	if ((m->flags & MOPT_NO_EXT3) && IS_EXT3_SB(sb)) {
1480 		ext4_msg(sb, KERN_ERR,
1481 			 "Mount option \"%s\" incompatible with ext3", opt);
1482 		return -1;
1483 	}
1484 
1485 	if (args->from && !(m->flags & MOPT_STRING) && match_int(args, &arg))
1486 		return -1;
1487 	if (args->from && (m->flags & MOPT_GTE0) && (arg < 0))
1488 		return -1;
1489 	if (m->flags & MOPT_EXPLICIT)
1490 		set_opt2(sb, EXPLICIT_DELALLOC);
1491 	if (m->flags & MOPT_CLEAR_ERR)
1492 		clear_opt(sb, ERRORS_MASK);
1493 	if (token == Opt_noquota && sb_any_quota_loaded(sb)) {
1494 		ext4_msg(sb, KERN_ERR, "Cannot change quota "
1495 			 "options when quota turned on");
1496 		return -1;
1497 	}
1498 
1499 	if (m->flags & MOPT_NOSUPPORT) {
1500 		ext4_msg(sb, KERN_ERR, "%s option not supported", opt);
1501 	} else if (token == Opt_commit) {
1502 		if (arg == 0)
1503 			arg = JBD2_DEFAULT_MAX_COMMIT_AGE;
1504 		sbi->s_commit_interval = HZ * arg;
1505 	} else if (token == Opt_max_batch_time) {
1506 		sbi->s_max_batch_time = arg;
1507 	} else if (token == Opt_min_batch_time) {
1508 		sbi->s_min_batch_time = arg;
1509 	} else if (token == Opt_inode_readahead_blks) {
1510 		if (arg && (arg > (1 << 30) || !is_power_of_2(arg))) {
1511 			ext4_msg(sb, KERN_ERR,
1512 				 "EXT4-fs: inode_readahead_blks must be "
1513 				 "0 or a power of 2 smaller than 2^31");
1514 			return -1;
1515 		}
1516 		sbi->s_inode_readahead_blks = arg;
1517 	} else if (token == Opt_init_itable) {
1518 		set_opt(sb, INIT_INODE_TABLE);
1519 		if (!args->from)
1520 			arg = EXT4_DEF_LI_WAIT_MULT;
1521 		sbi->s_li_wait_mult = arg;
1522 	} else if (token == Opt_max_dir_size_kb) {
1523 		sbi->s_max_dir_size_kb = arg;
1524 	} else if (token == Opt_stripe) {
1525 		sbi->s_stripe = arg;
1526 	} else if (token == Opt_resuid) {
1527 		uid = make_kuid(current_user_ns(), arg);
1528 		if (!uid_valid(uid)) {
1529 			ext4_msg(sb, KERN_ERR, "Invalid uid value %d", arg);
1530 			return -1;
1531 		}
1532 		sbi->s_resuid = uid;
1533 	} else if (token == Opt_resgid) {
1534 		gid = make_kgid(current_user_ns(), arg);
1535 		if (!gid_valid(gid)) {
1536 			ext4_msg(sb, KERN_ERR, "Invalid gid value %d", arg);
1537 			return -1;
1538 		}
1539 		sbi->s_resgid = gid;
1540 	} else if (token == Opt_journal_dev) {
1541 		if (is_remount) {
1542 			ext4_msg(sb, KERN_ERR,
1543 				 "Cannot specify journal on remount");
1544 			return -1;
1545 		}
1546 		*journal_devnum = arg;
1547 	} else if (token == Opt_journal_path) {
1548 		char *journal_path;
1549 		struct inode *journal_inode;
1550 		struct path path;
1551 		int error;
1552 
1553 		if (is_remount) {
1554 			ext4_msg(sb, KERN_ERR,
1555 				 "Cannot specify journal on remount");
1556 			return -1;
1557 		}
1558 		journal_path = match_strdup(&args[0]);
1559 		if (!journal_path) {
1560 			ext4_msg(sb, KERN_ERR, "error: could not dup "
1561 				"journal device string");
1562 			return -1;
1563 		}
1564 
1565 		error = kern_path(journal_path, LOOKUP_FOLLOW, &path);
1566 		if (error) {
1567 			ext4_msg(sb, KERN_ERR, "error: could not find "
1568 				"journal device path: error %d", error);
1569 			kfree(journal_path);
1570 			return -1;
1571 		}
1572 
1573 		journal_inode = path.dentry->d_inode;
1574 		if (!S_ISBLK(journal_inode->i_mode)) {
1575 			ext4_msg(sb, KERN_ERR, "error: journal path %s "
1576 				"is not a block device", journal_path);
1577 			path_put(&path);
1578 			kfree(journal_path);
1579 			return -1;
1580 		}
1581 
1582 		*journal_devnum = new_encode_dev(journal_inode->i_rdev);
1583 		path_put(&path);
1584 		kfree(journal_path);
1585 	} else if (token == Opt_journal_ioprio) {
1586 		if (arg > 7) {
1587 			ext4_msg(sb, KERN_ERR, "Invalid journal IO priority"
1588 				 " (must be 0-7)");
1589 			return -1;
1590 		}
1591 		*journal_ioprio =
1592 			IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, arg);
1593 	} else if (m->flags & MOPT_DATAJ) {
1594 		if (is_remount) {
1595 			if (!sbi->s_journal)
1596 				ext4_msg(sb, KERN_WARNING, "Remounting file system with no journal so ignoring journalled data option");
1597 			else if (test_opt(sb, DATA_FLAGS) != m->mount_opt) {
1598 				ext4_msg(sb, KERN_ERR,
1599 					 "Cannot change data mode on remount");
1600 				return -1;
1601 			}
1602 		} else {
1603 			clear_opt(sb, DATA_FLAGS);
1604 			sbi->s_mount_opt |= m->mount_opt;
1605 		}
1606 #ifdef CONFIG_QUOTA
1607 	} else if (m->flags & MOPT_QFMT) {
1608 		if (sb_any_quota_loaded(sb) &&
1609 		    sbi->s_jquota_fmt != m->mount_opt) {
1610 			ext4_msg(sb, KERN_ERR, "Cannot change journaled "
1611 				 "quota options when quota turned on");
1612 			return -1;
1613 		}
1614 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
1615 					       EXT4_FEATURE_RO_COMPAT_QUOTA)) {
1616 			ext4_msg(sb, KERN_ERR,
1617 				 "Cannot set journaled quota options "
1618 				 "when QUOTA feature is enabled");
1619 			return -1;
1620 		}
1621 		sbi->s_jquota_fmt = m->mount_opt;
1622 #endif
1623 	} else {
1624 		if (!args->from)
1625 			arg = 1;
1626 		if (m->flags & MOPT_CLEAR)
1627 			arg = !arg;
1628 		else if (unlikely(!(m->flags & MOPT_SET))) {
1629 			ext4_msg(sb, KERN_WARNING,
1630 				 "buggy handling of option %s", opt);
1631 			WARN_ON(1);
1632 			return -1;
1633 		}
1634 		if (arg != 0)
1635 			sbi->s_mount_opt |= m->mount_opt;
1636 		else
1637 			sbi->s_mount_opt &= ~m->mount_opt;
1638 	}
1639 	return 1;
1640 }
1641 
1642 static int parse_options(char *options, struct super_block *sb,
1643 			 unsigned long *journal_devnum,
1644 			 unsigned int *journal_ioprio,
1645 			 int is_remount)
1646 {
1647 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1648 	char *p;
1649 	substring_t args[MAX_OPT_ARGS];
1650 	int token;
1651 
1652 	if (!options)
1653 		return 1;
1654 
1655 	while ((p = strsep(&options, ",")) != NULL) {
1656 		if (!*p)
1657 			continue;
1658 		/*
1659 		 * Initialize args struct so we know whether arg was
1660 		 * found; some options take optional arguments.
1661 		 */
1662 		args[0].to = args[0].from = NULL;
1663 		token = match_token(p, tokens, args);
1664 		if (handle_mount_opt(sb, p, token, args, journal_devnum,
1665 				     journal_ioprio, is_remount) < 0)
1666 			return 0;
1667 	}
1668 #ifdef CONFIG_QUOTA
1669 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA) &&
1670 	    (test_opt(sb, USRQUOTA) || test_opt(sb, GRPQUOTA))) {
1671 		ext4_msg(sb, KERN_ERR, "Cannot set quota options when QUOTA "
1672 			 "feature is enabled");
1673 		return 0;
1674 	}
1675 	if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
1676 		if (test_opt(sb, USRQUOTA) && sbi->s_qf_names[USRQUOTA])
1677 			clear_opt(sb, USRQUOTA);
1678 
1679 		if (test_opt(sb, GRPQUOTA) && sbi->s_qf_names[GRPQUOTA])
1680 			clear_opt(sb, GRPQUOTA);
1681 
1682 		if (test_opt(sb, GRPQUOTA) || test_opt(sb, USRQUOTA)) {
1683 			ext4_msg(sb, KERN_ERR, "old and new quota "
1684 					"format mixing");
1685 			return 0;
1686 		}
1687 
1688 		if (!sbi->s_jquota_fmt) {
1689 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1690 					"not specified");
1691 			return 0;
1692 		}
1693 	}
1694 #endif
1695 	if (test_opt(sb, DIOREAD_NOLOCK)) {
1696 		int blocksize =
1697 			BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
1698 
1699 		if (blocksize < PAGE_CACHE_SIZE) {
1700 			ext4_msg(sb, KERN_ERR, "can't mount with "
1701 				 "dioread_nolock if block size != PAGE_SIZE");
1702 			return 0;
1703 		}
1704 	}
1705 	return 1;
1706 }
1707 
1708 static inline void ext4_show_quota_options(struct seq_file *seq,
1709 					   struct super_block *sb)
1710 {
1711 #if defined(CONFIG_QUOTA)
1712 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1713 
1714 	if (sbi->s_jquota_fmt) {
1715 		char *fmtname = "";
1716 
1717 		switch (sbi->s_jquota_fmt) {
1718 		case QFMT_VFS_OLD:
1719 			fmtname = "vfsold";
1720 			break;
1721 		case QFMT_VFS_V0:
1722 			fmtname = "vfsv0";
1723 			break;
1724 		case QFMT_VFS_V1:
1725 			fmtname = "vfsv1";
1726 			break;
1727 		}
1728 		seq_printf(seq, ",jqfmt=%s", fmtname);
1729 	}
1730 
1731 	if (sbi->s_qf_names[USRQUOTA])
1732 		seq_printf(seq, ",usrjquota=%s", sbi->s_qf_names[USRQUOTA]);
1733 
1734 	if (sbi->s_qf_names[GRPQUOTA])
1735 		seq_printf(seq, ",grpjquota=%s", sbi->s_qf_names[GRPQUOTA]);
1736 #endif
1737 }
1738 
1739 static const char *token2str(int token)
1740 {
1741 	const struct match_token *t;
1742 
1743 	for (t = tokens; t->token != Opt_err; t++)
1744 		if (t->token == token && !strchr(t->pattern, '='))
1745 			break;
1746 	return t->pattern;
1747 }
1748 
1749 /*
1750  * Show an option if
1751  *  - it's set to a non-default value OR
1752  *  - if the per-sb default is different from the global default
1753  */
1754 static int _ext4_show_options(struct seq_file *seq, struct super_block *sb,
1755 			      int nodefs)
1756 {
1757 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1758 	struct ext4_super_block *es = sbi->s_es;
1759 	int def_errors, def_mount_opt = nodefs ? 0 : sbi->s_def_mount_opt;
1760 	const struct mount_opts *m;
1761 	char sep = nodefs ? '\n' : ',';
1762 
1763 #define SEQ_OPTS_PUTS(str) seq_printf(seq, "%c" str, sep)
1764 #define SEQ_OPTS_PRINT(str, arg) seq_printf(seq, "%c" str, sep, arg)
1765 
1766 	if (sbi->s_sb_block != 1)
1767 		SEQ_OPTS_PRINT("sb=%llu", sbi->s_sb_block);
1768 
1769 	for (m = ext4_mount_opts; m->token != Opt_err; m++) {
1770 		int want_set = m->flags & MOPT_SET;
1771 		if (((m->flags & (MOPT_SET|MOPT_CLEAR)) == 0) ||
1772 		    (m->flags & MOPT_CLEAR_ERR))
1773 			continue;
1774 		if (!(m->mount_opt & (sbi->s_mount_opt ^ def_mount_opt)))
1775 			continue; /* skip if same as the default */
1776 		if ((want_set &&
1777 		     (sbi->s_mount_opt & m->mount_opt) != m->mount_opt) ||
1778 		    (!want_set && (sbi->s_mount_opt & m->mount_opt)))
1779 			continue; /* select Opt_noFoo vs Opt_Foo */
1780 		SEQ_OPTS_PRINT("%s", token2str(m->token));
1781 	}
1782 
1783 	if (nodefs || !uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT4_DEF_RESUID)) ||
1784 	    le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID)
1785 		SEQ_OPTS_PRINT("resuid=%u",
1786 				from_kuid_munged(&init_user_ns, sbi->s_resuid));
1787 	if (nodefs || !gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT4_DEF_RESGID)) ||
1788 	    le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID)
1789 		SEQ_OPTS_PRINT("resgid=%u",
1790 				from_kgid_munged(&init_user_ns, sbi->s_resgid));
1791 	def_errors = nodefs ? -1 : le16_to_cpu(es->s_errors);
1792 	if (test_opt(sb, ERRORS_RO) && def_errors != EXT4_ERRORS_RO)
1793 		SEQ_OPTS_PUTS("errors=remount-ro");
1794 	if (test_opt(sb, ERRORS_CONT) && def_errors != EXT4_ERRORS_CONTINUE)
1795 		SEQ_OPTS_PUTS("errors=continue");
1796 	if (test_opt(sb, ERRORS_PANIC) && def_errors != EXT4_ERRORS_PANIC)
1797 		SEQ_OPTS_PUTS("errors=panic");
1798 	if (nodefs || sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ)
1799 		SEQ_OPTS_PRINT("commit=%lu", sbi->s_commit_interval / HZ);
1800 	if (nodefs || sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME)
1801 		SEQ_OPTS_PRINT("min_batch_time=%u", sbi->s_min_batch_time);
1802 	if (nodefs || sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME)
1803 		SEQ_OPTS_PRINT("max_batch_time=%u", sbi->s_max_batch_time);
1804 	if (sb->s_flags & MS_I_VERSION)
1805 		SEQ_OPTS_PUTS("i_version");
1806 	if (nodefs || sbi->s_stripe)
1807 		SEQ_OPTS_PRINT("stripe=%lu", sbi->s_stripe);
1808 	if (EXT4_MOUNT_DATA_FLAGS & (sbi->s_mount_opt ^ def_mount_opt)) {
1809 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
1810 			SEQ_OPTS_PUTS("data=journal");
1811 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
1812 			SEQ_OPTS_PUTS("data=ordered");
1813 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
1814 			SEQ_OPTS_PUTS("data=writeback");
1815 	}
1816 	if (nodefs ||
1817 	    sbi->s_inode_readahead_blks != EXT4_DEF_INODE_READAHEAD_BLKS)
1818 		SEQ_OPTS_PRINT("inode_readahead_blks=%u",
1819 			       sbi->s_inode_readahead_blks);
1820 
1821 	if (nodefs || (test_opt(sb, INIT_INODE_TABLE) &&
1822 		       (sbi->s_li_wait_mult != EXT4_DEF_LI_WAIT_MULT)))
1823 		SEQ_OPTS_PRINT("init_itable=%u", sbi->s_li_wait_mult);
1824 	if (nodefs || sbi->s_max_dir_size_kb)
1825 		SEQ_OPTS_PRINT("max_dir_size_kb=%u", sbi->s_max_dir_size_kb);
1826 
1827 	ext4_show_quota_options(seq, sb);
1828 	return 0;
1829 }
1830 
1831 static int ext4_show_options(struct seq_file *seq, struct dentry *root)
1832 {
1833 	return _ext4_show_options(seq, root->d_sb, 0);
1834 }
1835 
1836 static int options_seq_show(struct seq_file *seq, void *offset)
1837 {
1838 	struct super_block *sb = seq->private;
1839 	int rc;
1840 
1841 	seq_puts(seq, (sb->s_flags & MS_RDONLY) ? "ro" : "rw");
1842 	rc = _ext4_show_options(seq, sb, 1);
1843 	seq_puts(seq, "\n");
1844 	return rc;
1845 }
1846 
1847 static int options_open_fs(struct inode *inode, struct file *file)
1848 {
1849 	return single_open(file, options_seq_show, PDE_DATA(inode));
1850 }
1851 
1852 static const struct file_operations ext4_seq_options_fops = {
1853 	.owner = THIS_MODULE,
1854 	.open = options_open_fs,
1855 	.read = seq_read,
1856 	.llseek = seq_lseek,
1857 	.release = single_release,
1858 };
1859 
1860 static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
1861 			    int read_only)
1862 {
1863 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1864 	int res = 0;
1865 
1866 	if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
1867 		ext4_msg(sb, KERN_ERR, "revision level too high, "
1868 			 "forcing read-only mode");
1869 		res = MS_RDONLY;
1870 	}
1871 	if (read_only)
1872 		goto done;
1873 	if (!(sbi->s_mount_state & EXT4_VALID_FS))
1874 		ext4_msg(sb, KERN_WARNING, "warning: mounting unchecked fs, "
1875 			 "running e2fsck is recommended");
1876 	else if (sbi->s_mount_state & EXT4_ERROR_FS)
1877 		ext4_msg(sb, KERN_WARNING,
1878 			 "warning: mounting fs with errors, "
1879 			 "running e2fsck is recommended");
1880 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) > 0 &&
1881 		 le16_to_cpu(es->s_mnt_count) >=
1882 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
1883 		ext4_msg(sb, KERN_WARNING,
1884 			 "warning: maximal mount count reached, "
1885 			 "running e2fsck is recommended");
1886 	else if (le32_to_cpu(es->s_checkinterval) &&
1887 		(le32_to_cpu(es->s_lastcheck) +
1888 			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
1889 		ext4_msg(sb, KERN_WARNING,
1890 			 "warning: checktime reached, "
1891 			 "running e2fsck is recommended");
1892 	if (!sbi->s_journal)
1893 		es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1894 	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
1895 		es->s_max_mnt_count = cpu_to_le16(EXT4_DFL_MAX_MNT_COUNT);
1896 	le16_add_cpu(&es->s_mnt_count, 1);
1897 	es->s_mtime = cpu_to_le32(get_seconds());
1898 	ext4_update_dynamic_rev(sb);
1899 	if (sbi->s_journal)
1900 		EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
1901 
1902 	ext4_commit_super(sb, 1);
1903 done:
1904 	if (test_opt(sb, DEBUG))
1905 		printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, "
1906 				"bpg=%lu, ipg=%lu, mo=%04x, mo2=%04x]\n",
1907 			sb->s_blocksize,
1908 			sbi->s_groups_count,
1909 			EXT4_BLOCKS_PER_GROUP(sb),
1910 			EXT4_INODES_PER_GROUP(sb),
1911 			sbi->s_mount_opt, sbi->s_mount_opt2);
1912 
1913 	cleancache_init_fs(sb);
1914 	return res;
1915 }
1916 
1917 int ext4_alloc_flex_bg_array(struct super_block *sb, ext4_group_t ngroup)
1918 {
1919 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1920 	struct flex_groups *new_groups;
1921 	int size;
1922 
1923 	if (!sbi->s_log_groups_per_flex)
1924 		return 0;
1925 
1926 	size = ext4_flex_group(sbi, ngroup - 1) + 1;
1927 	if (size <= sbi->s_flex_groups_allocated)
1928 		return 0;
1929 
1930 	size = roundup_pow_of_two(size * sizeof(struct flex_groups));
1931 	new_groups = ext4_kvzalloc(size, GFP_KERNEL);
1932 	if (!new_groups) {
1933 		ext4_msg(sb, KERN_ERR, "not enough memory for %d flex groups",
1934 			 size / (int) sizeof(struct flex_groups));
1935 		return -ENOMEM;
1936 	}
1937 
1938 	if (sbi->s_flex_groups) {
1939 		memcpy(new_groups, sbi->s_flex_groups,
1940 		       (sbi->s_flex_groups_allocated *
1941 			sizeof(struct flex_groups)));
1942 		ext4_kvfree(sbi->s_flex_groups);
1943 	}
1944 	sbi->s_flex_groups = new_groups;
1945 	sbi->s_flex_groups_allocated = size / sizeof(struct flex_groups);
1946 	return 0;
1947 }
1948 
1949 static int ext4_fill_flex_info(struct super_block *sb)
1950 {
1951 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1952 	struct ext4_group_desc *gdp = NULL;
1953 	ext4_group_t flex_group;
1954 	int i, err;
1955 
1956 	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
1957 	if (sbi->s_log_groups_per_flex < 1 || sbi->s_log_groups_per_flex > 31) {
1958 		sbi->s_log_groups_per_flex = 0;
1959 		return 1;
1960 	}
1961 
1962 	err = ext4_alloc_flex_bg_array(sb, sbi->s_groups_count);
1963 	if (err)
1964 		goto failed;
1965 
1966 	for (i = 0; i < sbi->s_groups_count; i++) {
1967 		gdp = ext4_get_group_desc(sb, i, NULL);
1968 
1969 		flex_group = ext4_flex_group(sbi, i);
1970 		atomic_add(ext4_free_inodes_count(sb, gdp),
1971 			   &sbi->s_flex_groups[flex_group].free_inodes);
1972 		atomic64_add(ext4_free_group_clusters(sb, gdp),
1973 			     &sbi->s_flex_groups[flex_group].free_clusters);
1974 		atomic_add(ext4_used_dirs_count(sb, gdp),
1975 			   &sbi->s_flex_groups[flex_group].used_dirs);
1976 	}
1977 
1978 	return 1;
1979 failed:
1980 	return 0;
1981 }
1982 
1983 static __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
1984 				   struct ext4_group_desc *gdp)
1985 {
1986 	int offset;
1987 	__u16 crc = 0;
1988 	__le32 le_group = cpu_to_le32(block_group);
1989 
1990 	if (ext4_has_metadata_csum(sbi->s_sb)) {
1991 		/* Use new metadata_csum algorithm */
1992 		__le16 save_csum;
1993 		__u32 csum32;
1994 
1995 		save_csum = gdp->bg_checksum;
1996 		gdp->bg_checksum = 0;
1997 		csum32 = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&le_group,
1998 				     sizeof(le_group));
1999 		csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp,
2000 				     sbi->s_desc_size);
2001 		gdp->bg_checksum = save_csum;
2002 
2003 		crc = csum32 & 0xFFFF;
2004 		goto out;
2005 	}
2006 
2007 	/* old crc16 code */
2008 	if (!(sbi->s_es->s_feature_ro_compat &
2009 	      cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)))
2010 		return 0;
2011 
2012 	offset = offsetof(struct ext4_group_desc, bg_checksum);
2013 
2014 	crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
2015 	crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
2016 	crc = crc16(crc, (__u8 *)gdp, offset);
2017 	offset += sizeof(gdp->bg_checksum); /* skip checksum */
2018 	/* for checksum of struct ext4_group_desc do the rest...*/
2019 	if ((sbi->s_es->s_feature_incompat &
2020 	     cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) &&
2021 	    offset < le16_to_cpu(sbi->s_es->s_desc_size))
2022 		crc = crc16(crc, (__u8 *)gdp + offset,
2023 			    le16_to_cpu(sbi->s_es->s_desc_size) -
2024 				offset);
2025 
2026 out:
2027 	return cpu_to_le16(crc);
2028 }
2029 
2030 int ext4_group_desc_csum_verify(struct super_block *sb, __u32 block_group,
2031 				struct ext4_group_desc *gdp)
2032 {
2033 	if (ext4_has_group_desc_csum(sb) &&
2034 	    (gdp->bg_checksum != ext4_group_desc_csum(EXT4_SB(sb),
2035 						      block_group, gdp)))
2036 		return 0;
2037 
2038 	return 1;
2039 }
2040 
2041 void ext4_group_desc_csum_set(struct super_block *sb, __u32 block_group,
2042 			      struct ext4_group_desc *gdp)
2043 {
2044 	if (!ext4_has_group_desc_csum(sb))
2045 		return;
2046 	gdp->bg_checksum = ext4_group_desc_csum(EXT4_SB(sb), block_group, gdp);
2047 }
2048 
2049 /* Called at mount-time, super-block is locked */
2050 static int ext4_check_descriptors(struct super_block *sb,
2051 				  ext4_group_t *first_not_zeroed)
2052 {
2053 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2054 	ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
2055 	ext4_fsblk_t last_block;
2056 	ext4_fsblk_t block_bitmap;
2057 	ext4_fsblk_t inode_bitmap;
2058 	ext4_fsblk_t inode_table;
2059 	int flexbg_flag = 0;
2060 	ext4_group_t i, grp = sbi->s_groups_count;
2061 
2062 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
2063 		flexbg_flag = 1;
2064 
2065 	ext4_debug("Checking group descriptors");
2066 
2067 	for (i = 0; i < sbi->s_groups_count; i++) {
2068 		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
2069 
2070 		if (i == sbi->s_groups_count - 1 || flexbg_flag)
2071 			last_block = ext4_blocks_count(sbi->s_es) - 1;
2072 		else
2073 			last_block = first_block +
2074 				(EXT4_BLOCKS_PER_GROUP(sb) - 1);
2075 
2076 		if ((grp == sbi->s_groups_count) &&
2077 		   !(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2078 			grp = i;
2079 
2080 		block_bitmap = ext4_block_bitmap(sb, gdp);
2081 		if (block_bitmap < first_block || block_bitmap > last_block) {
2082 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2083 			       "Block bitmap for group %u not in group "
2084 			       "(block %llu)!", i, block_bitmap);
2085 			return 0;
2086 		}
2087 		inode_bitmap = ext4_inode_bitmap(sb, gdp);
2088 		if (inode_bitmap < first_block || inode_bitmap > last_block) {
2089 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2090 			       "Inode bitmap for group %u not in group "
2091 			       "(block %llu)!", i, inode_bitmap);
2092 			return 0;
2093 		}
2094 		inode_table = ext4_inode_table(sb, gdp);
2095 		if (inode_table < first_block ||
2096 		    inode_table + sbi->s_itb_per_group - 1 > last_block) {
2097 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2098 			       "Inode table for group %u not in group "
2099 			       "(block %llu)!", i, inode_table);
2100 			return 0;
2101 		}
2102 		ext4_lock_group(sb, i);
2103 		if (!ext4_group_desc_csum_verify(sb, i, gdp)) {
2104 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2105 				 "Checksum for group %u failed (%u!=%u)",
2106 				 i, le16_to_cpu(ext4_group_desc_csum(sbi, i,
2107 				     gdp)), le16_to_cpu(gdp->bg_checksum));
2108 			if (!(sb->s_flags & MS_RDONLY)) {
2109 				ext4_unlock_group(sb, i);
2110 				return 0;
2111 			}
2112 		}
2113 		ext4_unlock_group(sb, i);
2114 		if (!flexbg_flag)
2115 			first_block += EXT4_BLOCKS_PER_GROUP(sb);
2116 	}
2117 	if (NULL != first_not_zeroed)
2118 		*first_not_zeroed = grp;
2119 	return 1;
2120 }
2121 
2122 /* ext4_orphan_cleanup() walks a singly-linked list of inodes (starting at
2123  * the superblock) which were deleted from all directories, but held open by
2124  * a process at the time of a crash.  We walk the list and try to delete these
2125  * inodes at recovery time (only with a read-write filesystem).
2126  *
2127  * In order to keep the orphan inode chain consistent during traversal (in
2128  * case of crash during recovery), we link each inode into the superblock
2129  * orphan list_head and handle it the same way as an inode deletion during
2130  * normal operation (which journals the operations for us).
2131  *
2132  * We only do an iget() and an iput() on each inode, which is very safe if we
2133  * accidentally point at an in-use or already deleted inode.  The worst that
2134  * can happen in this case is that we get a "bit already cleared" message from
2135  * ext4_free_inode().  The only reason we would point at a wrong inode is if
2136  * e2fsck was run on this filesystem, and it must have already done the orphan
2137  * inode cleanup for us, so we can safely abort without any further action.
2138  */
2139 static void ext4_orphan_cleanup(struct super_block *sb,
2140 				struct ext4_super_block *es)
2141 {
2142 	unsigned int s_flags = sb->s_flags;
2143 	int nr_orphans = 0, nr_truncates = 0;
2144 #ifdef CONFIG_QUOTA
2145 	int i;
2146 #endif
2147 	if (!es->s_last_orphan) {
2148 		jbd_debug(4, "no orphan inodes to clean up\n");
2149 		return;
2150 	}
2151 
2152 	if (bdev_read_only(sb->s_bdev)) {
2153 		ext4_msg(sb, KERN_ERR, "write access "
2154 			"unavailable, skipping orphan cleanup");
2155 		return;
2156 	}
2157 
2158 	/* Check if feature set would not allow a r/w mount */
2159 	if (!ext4_feature_set_ok(sb, 0)) {
2160 		ext4_msg(sb, KERN_INFO, "Skipping orphan cleanup due to "
2161 			 "unknown ROCOMPAT features");
2162 		return;
2163 	}
2164 
2165 	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
2166 		/* don't clear list on RO mount w/ errors */
2167 		if (es->s_last_orphan && !(s_flags & MS_RDONLY)) {
2168 			ext4_msg(sb, KERN_INFO, "Errors on filesystem, "
2169 				  "clearing orphan list.\n");
2170 			es->s_last_orphan = 0;
2171 		}
2172 		jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
2173 		return;
2174 	}
2175 
2176 	if (s_flags & MS_RDONLY) {
2177 		ext4_msg(sb, KERN_INFO, "orphan cleanup on readonly fs");
2178 		sb->s_flags &= ~MS_RDONLY;
2179 	}
2180 #ifdef CONFIG_QUOTA
2181 	/* Needed for iput() to work correctly and not trash data */
2182 	sb->s_flags |= MS_ACTIVE;
2183 	/* Turn on quotas so that they are updated correctly */
2184 	for (i = 0; i < EXT4_MAXQUOTAS; i++) {
2185 		if (EXT4_SB(sb)->s_qf_names[i]) {
2186 			int ret = ext4_quota_on_mount(sb, i);
2187 			if (ret < 0)
2188 				ext4_msg(sb, KERN_ERR,
2189 					"Cannot turn on journaled "
2190 					"quota: error %d", ret);
2191 		}
2192 	}
2193 #endif
2194 
2195 	while (es->s_last_orphan) {
2196 		struct inode *inode;
2197 
2198 		inode = ext4_orphan_get(sb, le32_to_cpu(es->s_last_orphan));
2199 		if (IS_ERR(inode)) {
2200 			es->s_last_orphan = 0;
2201 			break;
2202 		}
2203 
2204 		list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
2205 		dquot_initialize(inode);
2206 		if (inode->i_nlink) {
2207 			if (test_opt(sb, DEBUG))
2208 				ext4_msg(sb, KERN_DEBUG,
2209 					"%s: truncating inode %lu to %lld bytes",
2210 					__func__, inode->i_ino, inode->i_size);
2211 			jbd_debug(2, "truncating inode %lu to %lld bytes\n",
2212 				  inode->i_ino, inode->i_size);
2213 			mutex_lock(&inode->i_mutex);
2214 			truncate_inode_pages(inode->i_mapping, inode->i_size);
2215 			ext4_truncate(inode);
2216 			mutex_unlock(&inode->i_mutex);
2217 			nr_truncates++;
2218 		} else {
2219 			if (test_opt(sb, DEBUG))
2220 				ext4_msg(sb, KERN_DEBUG,
2221 					"%s: deleting unreferenced inode %lu",
2222 					__func__, inode->i_ino);
2223 			jbd_debug(2, "deleting unreferenced inode %lu\n",
2224 				  inode->i_ino);
2225 			nr_orphans++;
2226 		}
2227 		iput(inode);  /* The delete magic happens here! */
2228 	}
2229 
2230 #define PLURAL(x) (x), ((x) == 1) ? "" : "s"
2231 
2232 	if (nr_orphans)
2233 		ext4_msg(sb, KERN_INFO, "%d orphan inode%s deleted",
2234 		       PLURAL(nr_orphans));
2235 	if (nr_truncates)
2236 		ext4_msg(sb, KERN_INFO, "%d truncate%s cleaned up",
2237 		       PLURAL(nr_truncates));
2238 #ifdef CONFIG_QUOTA
2239 	/* Turn quotas off */
2240 	for (i = 0; i < EXT4_MAXQUOTAS; i++) {
2241 		if (sb_dqopt(sb)->files[i])
2242 			dquot_quota_off(sb, i);
2243 	}
2244 #endif
2245 	sb->s_flags = s_flags; /* Restore MS_RDONLY status */
2246 }
2247 
2248 /*
2249  * Maximal extent format file size.
2250  * Resulting logical blkno at s_maxbytes must fit in our on-disk
2251  * extent format containers, within a sector_t, and within i_blocks
2252  * in the vfs.  ext4 inode has 48 bits of i_block in fsblock units,
2253  * so that won't be a limiting factor.
2254  *
2255  * However there is other limiting factor. We do store extents in the form
2256  * of starting block and length, hence the resulting length of the extent
2257  * covering maximum file size must fit into on-disk format containers as
2258  * well. Given that length is always by 1 unit bigger than max unit (because
2259  * we count 0 as well) we have to lower the s_maxbytes by one fs block.
2260  *
2261  * Note, this does *not* consider any metadata overhead for vfs i_blocks.
2262  */
2263 static loff_t ext4_max_size(int blkbits, int has_huge_files)
2264 {
2265 	loff_t res;
2266 	loff_t upper_limit = MAX_LFS_FILESIZE;
2267 
2268 	/* small i_blocks in vfs inode? */
2269 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2270 		/*
2271 		 * CONFIG_LBDAF is not enabled implies the inode
2272 		 * i_block represent total blocks in 512 bytes
2273 		 * 32 == size of vfs inode i_blocks * 8
2274 		 */
2275 		upper_limit = (1LL << 32) - 1;
2276 
2277 		/* total blocks in file system block size */
2278 		upper_limit >>= (blkbits - 9);
2279 		upper_limit <<= blkbits;
2280 	}
2281 
2282 	/*
2283 	 * 32-bit extent-start container, ee_block. We lower the maxbytes
2284 	 * by one fs block, so ee_len can cover the extent of maximum file
2285 	 * size
2286 	 */
2287 	res = (1LL << 32) - 1;
2288 	res <<= blkbits;
2289 
2290 	/* Sanity check against vm- & vfs- imposed limits */
2291 	if (res > upper_limit)
2292 		res = upper_limit;
2293 
2294 	return res;
2295 }
2296 
2297 /*
2298  * Maximal bitmap file size.  There is a direct, and {,double-,triple-}indirect
2299  * block limit, and also a limit of (2^48 - 1) 512-byte sectors in i_blocks.
2300  * We need to be 1 filesystem block less than the 2^48 sector limit.
2301  */
2302 static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
2303 {
2304 	loff_t res = EXT4_NDIR_BLOCKS;
2305 	int meta_blocks;
2306 	loff_t upper_limit;
2307 	/* This is calculated to be the largest file size for a dense, block
2308 	 * mapped file such that the file's total number of 512-byte sectors,
2309 	 * including data and all indirect blocks, does not exceed (2^48 - 1).
2310 	 *
2311 	 * __u32 i_blocks_lo and _u16 i_blocks_high represent the total
2312 	 * number of 512-byte sectors of the file.
2313 	 */
2314 
2315 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2316 		/*
2317 		 * !has_huge_files or CONFIG_LBDAF not enabled implies that
2318 		 * the inode i_block field represents total file blocks in
2319 		 * 2^32 512-byte sectors == size of vfs inode i_blocks * 8
2320 		 */
2321 		upper_limit = (1LL << 32) - 1;
2322 
2323 		/* total blocks in file system block size */
2324 		upper_limit >>= (bits - 9);
2325 
2326 	} else {
2327 		/*
2328 		 * We use 48 bit ext4_inode i_blocks
2329 		 * With EXT4_HUGE_FILE_FL set the i_blocks
2330 		 * represent total number of blocks in
2331 		 * file system block size
2332 		 */
2333 		upper_limit = (1LL << 48) - 1;
2334 
2335 	}
2336 
2337 	/* indirect blocks */
2338 	meta_blocks = 1;
2339 	/* double indirect blocks */
2340 	meta_blocks += 1 + (1LL << (bits-2));
2341 	/* tripple indirect blocks */
2342 	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
2343 
2344 	upper_limit -= meta_blocks;
2345 	upper_limit <<= bits;
2346 
2347 	res += 1LL << (bits-2);
2348 	res += 1LL << (2*(bits-2));
2349 	res += 1LL << (3*(bits-2));
2350 	res <<= bits;
2351 	if (res > upper_limit)
2352 		res = upper_limit;
2353 
2354 	if (res > MAX_LFS_FILESIZE)
2355 		res = MAX_LFS_FILESIZE;
2356 
2357 	return res;
2358 }
2359 
2360 static ext4_fsblk_t descriptor_loc(struct super_block *sb,
2361 				   ext4_fsblk_t logical_sb_block, int nr)
2362 {
2363 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2364 	ext4_group_t bg, first_meta_bg;
2365 	int has_super = 0;
2366 
2367 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
2368 
2369 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
2370 	    nr < first_meta_bg)
2371 		return logical_sb_block + nr + 1;
2372 	bg = sbi->s_desc_per_block * nr;
2373 	if (ext4_bg_has_super(sb, bg))
2374 		has_super = 1;
2375 
2376 	/*
2377 	 * If we have a meta_bg fs with 1k blocks, group 0's GDT is at
2378 	 * block 2, not 1.  If s_first_data_block == 0 (bigalloc is enabled
2379 	 * on modern mke2fs or blksize > 1k on older mke2fs) then we must
2380 	 * compensate.
2381 	 */
2382 	if (sb->s_blocksize == 1024 && nr == 0 &&
2383 	    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block) == 0)
2384 		has_super++;
2385 
2386 	return (has_super + ext4_group_first_block_no(sb, bg));
2387 }
2388 
2389 /**
2390  * ext4_get_stripe_size: Get the stripe size.
2391  * @sbi: In memory super block info
2392  *
2393  * If we have specified it via mount option, then
2394  * use the mount option value. If the value specified at mount time is
2395  * greater than the blocks per group use the super block value.
2396  * If the super block value is greater than blocks per group return 0.
2397  * Allocator needs it be less than blocks per group.
2398  *
2399  */
2400 static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi)
2401 {
2402 	unsigned long stride = le16_to_cpu(sbi->s_es->s_raid_stride);
2403 	unsigned long stripe_width =
2404 			le32_to_cpu(sbi->s_es->s_raid_stripe_width);
2405 	int ret;
2406 
2407 	if (sbi->s_stripe && sbi->s_stripe <= sbi->s_blocks_per_group)
2408 		ret = sbi->s_stripe;
2409 	else if (stripe_width <= sbi->s_blocks_per_group)
2410 		ret = stripe_width;
2411 	else if (stride <= sbi->s_blocks_per_group)
2412 		ret = stride;
2413 	else
2414 		ret = 0;
2415 
2416 	/*
2417 	 * If the stripe width is 1, this makes no sense and
2418 	 * we set it to 0 to turn off stripe handling code.
2419 	 */
2420 	if (ret <= 1)
2421 		ret = 0;
2422 
2423 	return ret;
2424 }
2425 
2426 /* sysfs supprt */
2427 
2428 struct ext4_attr {
2429 	struct attribute attr;
2430 	ssize_t (*show)(struct ext4_attr *, struct ext4_sb_info *, char *);
2431 	ssize_t (*store)(struct ext4_attr *, struct ext4_sb_info *,
2432 			 const char *, size_t);
2433 	union {
2434 		int offset;
2435 		int deprecated_val;
2436 	} u;
2437 };
2438 
2439 static int parse_strtoull(const char *buf,
2440 		unsigned long long max, unsigned long long *value)
2441 {
2442 	int ret;
2443 
2444 	ret = kstrtoull(skip_spaces(buf), 0, value);
2445 	if (!ret && *value > max)
2446 		ret = -EINVAL;
2447 	return ret;
2448 }
2449 
2450 static ssize_t delayed_allocation_blocks_show(struct ext4_attr *a,
2451 					      struct ext4_sb_info *sbi,
2452 					      char *buf)
2453 {
2454 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2455 		(s64) EXT4_C2B(sbi,
2456 			percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
2457 }
2458 
2459 static ssize_t session_write_kbytes_show(struct ext4_attr *a,
2460 					 struct ext4_sb_info *sbi, char *buf)
2461 {
2462 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
2463 
2464 	if (!sb->s_bdev->bd_part)
2465 		return snprintf(buf, PAGE_SIZE, "0\n");
2466 	return snprintf(buf, PAGE_SIZE, "%lu\n",
2467 			(part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
2468 			 sbi->s_sectors_written_start) >> 1);
2469 }
2470 
2471 static ssize_t lifetime_write_kbytes_show(struct ext4_attr *a,
2472 					  struct ext4_sb_info *sbi, char *buf)
2473 {
2474 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
2475 
2476 	if (!sb->s_bdev->bd_part)
2477 		return snprintf(buf, PAGE_SIZE, "0\n");
2478 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2479 			(unsigned long long)(sbi->s_kbytes_written +
2480 			((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
2481 			  EXT4_SB(sb)->s_sectors_written_start) >> 1)));
2482 }
2483 
2484 static ssize_t inode_readahead_blks_store(struct ext4_attr *a,
2485 					  struct ext4_sb_info *sbi,
2486 					  const char *buf, size_t count)
2487 {
2488 	unsigned long t;
2489 	int ret;
2490 
2491 	ret = kstrtoul(skip_spaces(buf), 0, &t);
2492 	if (ret)
2493 		return ret;
2494 
2495 	if (t && (!is_power_of_2(t) || t > 0x40000000))
2496 		return -EINVAL;
2497 
2498 	sbi->s_inode_readahead_blks = t;
2499 	return count;
2500 }
2501 
2502 static ssize_t sbi_ui_show(struct ext4_attr *a,
2503 			   struct ext4_sb_info *sbi, char *buf)
2504 {
2505 	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->u.offset);
2506 
2507 	return snprintf(buf, PAGE_SIZE, "%u\n", *ui);
2508 }
2509 
2510 static ssize_t sbi_ui_store(struct ext4_attr *a,
2511 			    struct ext4_sb_info *sbi,
2512 			    const char *buf, size_t count)
2513 {
2514 	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->u.offset);
2515 	unsigned long t;
2516 	int ret;
2517 
2518 	ret = kstrtoul(skip_spaces(buf), 0, &t);
2519 	if (ret)
2520 		return ret;
2521 	*ui = t;
2522 	return count;
2523 }
2524 
2525 static ssize_t es_ui_show(struct ext4_attr *a,
2526 			   struct ext4_sb_info *sbi, char *buf)
2527 {
2528 
2529 	unsigned int *ui = (unsigned int *) (((char *) sbi->s_es) +
2530 			   a->u.offset);
2531 
2532 	return snprintf(buf, PAGE_SIZE, "%u\n", *ui);
2533 }
2534 
2535 static ssize_t reserved_clusters_show(struct ext4_attr *a,
2536 				  struct ext4_sb_info *sbi, char *buf)
2537 {
2538 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2539 		(unsigned long long) atomic64_read(&sbi->s_resv_clusters));
2540 }
2541 
2542 static ssize_t reserved_clusters_store(struct ext4_attr *a,
2543 				   struct ext4_sb_info *sbi,
2544 				   const char *buf, size_t count)
2545 {
2546 	unsigned long long val;
2547 	int ret;
2548 
2549 	if (parse_strtoull(buf, -1ULL, &val))
2550 		return -EINVAL;
2551 	ret = ext4_reserve_clusters(sbi, val);
2552 
2553 	return ret ? ret : count;
2554 }
2555 
2556 static ssize_t trigger_test_error(struct ext4_attr *a,
2557 				  struct ext4_sb_info *sbi,
2558 				  const char *buf, size_t count)
2559 {
2560 	int len = count;
2561 
2562 	if (!capable(CAP_SYS_ADMIN))
2563 		return -EPERM;
2564 
2565 	if (len && buf[len-1] == '\n')
2566 		len--;
2567 
2568 	if (len)
2569 		ext4_error(sbi->s_sb, "%.*s", len, buf);
2570 	return count;
2571 }
2572 
2573 static ssize_t sbi_deprecated_show(struct ext4_attr *a,
2574 				   struct ext4_sb_info *sbi, char *buf)
2575 {
2576 	return snprintf(buf, PAGE_SIZE, "%d\n", a->u.deprecated_val);
2577 }
2578 
2579 #define EXT4_ATTR_OFFSET(_name,_mode,_show,_store,_elname) \
2580 static struct ext4_attr ext4_attr_##_name = {			\
2581 	.attr = {.name = __stringify(_name), .mode = _mode },	\
2582 	.show	= _show,					\
2583 	.store	= _store,					\
2584 	.u = {							\
2585 		.offset = offsetof(struct ext4_sb_info, _elname),\
2586 	},							\
2587 }
2588 
2589 #define EXT4_ATTR_OFFSET_ES(_name,_mode,_show,_store,_elname)		\
2590 static struct ext4_attr ext4_attr_##_name = {				\
2591 	.attr = {.name = __stringify(_name), .mode = _mode },		\
2592 	.show	= _show,						\
2593 	.store	= _store,						\
2594 	.u = {								\
2595 		.offset = offsetof(struct ext4_super_block, _elname),	\
2596 	},								\
2597 }
2598 
2599 #define EXT4_ATTR(name, mode, show, store) \
2600 static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store)
2601 
2602 #define EXT4_INFO_ATTR(name) EXT4_ATTR(name, 0444, NULL, NULL)
2603 #define EXT4_RO_ATTR(name) EXT4_ATTR(name, 0444, name##_show, NULL)
2604 #define EXT4_RW_ATTR(name) EXT4_ATTR(name, 0644, name##_show, name##_store)
2605 
2606 #define EXT4_RO_ATTR_ES_UI(name, elname)	\
2607 	EXT4_ATTR_OFFSET_ES(name, 0444, es_ui_show, NULL, elname)
2608 #define EXT4_RW_ATTR_SBI_UI(name, elname)	\
2609 	EXT4_ATTR_OFFSET(name, 0644, sbi_ui_show, sbi_ui_store, elname)
2610 
2611 #define ATTR_LIST(name) &ext4_attr_##name.attr
2612 #define EXT4_DEPRECATED_ATTR(_name, _val)	\
2613 static struct ext4_attr ext4_attr_##_name = {			\
2614 	.attr = {.name = __stringify(_name), .mode = 0444 },	\
2615 	.show	= sbi_deprecated_show,				\
2616 	.u = {							\
2617 		.deprecated_val = _val,				\
2618 	},							\
2619 }
2620 
2621 EXT4_RO_ATTR(delayed_allocation_blocks);
2622 EXT4_RO_ATTR(session_write_kbytes);
2623 EXT4_RO_ATTR(lifetime_write_kbytes);
2624 EXT4_RW_ATTR(reserved_clusters);
2625 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, sbi_ui_show,
2626 		 inode_readahead_blks_store, s_inode_readahead_blks);
2627 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
2628 EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
2629 EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
2630 EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
2631 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
2632 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
2633 EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
2634 EXT4_DEPRECATED_ATTR(max_writeback_mb_bump, 128);
2635 EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
2636 EXT4_ATTR(trigger_fs_error, 0200, NULL, trigger_test_error);
2637 EXT4_RW_ATTR_SBI_UI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
2638 EXT4_RW_ATTR_SBI_UI(err_ratelimit_burst, s_err_ratelimit_state.burst);
2639 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
2640 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
2641 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
2642 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
2643 EXT4_RO_ATTR_ES_UI(errors_count, s_error_count);
2644 EXT4_RO_ATTR_ES_UI(first_error_time, s_first_error_time);
2645 EXT4_RO_ATTR_ES_UI(last_error_time, s_last_error_time);
2646 
2647 static struct attribute *ext4_attrs[] = {
2648 	ATTR_LIST(delayed_allocation_blocks),
2649 	ATTR_LIST(session_write_kbytes),
2650 	ATTR_LIST(lifetime_write_kbytes),
2651 	ATTR_LIST(reserved_clusters),
2652 	ATTR_LIST(inode_readahead_blks),
2653 	ATTR_LIST(inode_goal),
2654 	ATTR_LIST(mb_stats),
2655 	ATTR_LIST(mb_max_to_scan),
2656 	ATTR_LIST(mb_min_to_scan),
2657 	ATTR_LIST(mb_order2_req),
2658 	ATTR_LIST(mb_stream_req),
2659 	ATTR_LIST(mb_group_prealloc),
2660 	ATTR_LIST(max_writeback_mb_bump),
2661 	ATTR_LIST(extent_max_zeroout_kb),
2662 	ATTR_LIST(trigger_fs_error),
2663 	ATTR_LIST(err_ratelimit_interval_ms),
2664 	ATTR_LIST(err_ratelimit_burst),
2665 	ATTR_LIST(warning_ratelimit_interval_ms),
2666 	ATTR_LIST(warning_ratelimit_burst),
2667 	ATTR_LIST(msg_ratelimit_interval_ms),
2668 	ATTR_LIST(msg_ratelimit_burst),
2669 	ATTR_LIST(errors_count),
2670 	ATTR_LIST(first_error_time),
2671 	ATTR_LIST(last_error_time),
2672 	NULL,
2673 };
2674 
2675 /* Features this copy of ext4 supports */
2676 EXT4_INFO_ATTR(lazy_itable_init);
2677 EXT4_INFO_ATTR(batched_discard);
2678 EXT4_INFO_ATTR(meta_bg_resize);
2679 
2680 static struct attribute *ext4_feat_attrs[] = {
2681 	ATTR_LIST(lazy_itable_init),
2682 	ATTR_LIST(batched_discard),
2683 	ATTR_LIST(meta_bg_resize),
2684 	NULL,
2685 };
2686 
2687 static ssize_t ext4_attr_show(struct kobject *kobj,
2688 			      struct attribute *attr, char *buf)
2689 {
2690 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2691 						s_kobj);
2692 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
2693 
2694 	return a->show ? a->show(a, sbi, buf) : 0;
2695 }
2696 
2697 static ssize_t ext4_attr_store(struct kobject *kobj,
2698 			       struct attribute *attr,
2699 			       const char *buf, size_t len)
2700 {
2701 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2702 						s_kobj);
2703 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
2704 
2705 	return a->store ? a->store(a, sbi, buf, len) : 0;
2706 }
2707 
2708 static void ext4_sb_release(struct kobject *kobj)
2709 {
2710 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2711 						s_kobj);
2712 	complete(&sbi->s_kobj_unregister);
2713 }
2714 
2715 static const struct sysfs_ops ext4_attr_ops = {
2716 	.show	= ext4_attr_show,
2717 	.store	= ext4_attr_store,
2718 };
2719 
2720 static struct kobj_type ext4_ktype = {
2721 	.default_attrs	= ext4_attrs,
2722 	.sysfs_ops	= &ext4_attr_ops,
2723 	.release	= ext4_sb_release,
2724 };
2725 
2726 static void ext4_feat_release(struct kobject *kobj)
2727 {
2728 	complete(&ext4_feat->f_kobj_unregister);
2729 }
2730 
2731 static ssize_t ext4_feat_show(struct kobject *kobj,
2732 			      struct attribute *attr, char *buf)
2733 {
2734 	return snprintf(buf, PAGE_SIZE, "supported\n");
2735 }
2736 
2737 /*
2738  * We can not use ext4_attr_show/store because it relies on the kobject
2739  * being embedded in the ext4_sb_info structure which is definitely not
2740  * true in this case.
2741  */
2742 static const struct sysfs_ops ext4_feat_ops = {
2743 	.show	= ext4_feat_show,
2744 	.store	= NULL,
2745 };
2746 
2747 static struct kobj_type ext4_feat_ktype = {
2748 	.default_attrs	= ext4_feat_attrs,
2749 	.sysfs_ops	= &ext4_feat_ops,
2750 	.release	= ext4_feat_release,
2751 };
2752 
2753 /*
2754  * Check whether this filesystem can be mounted based on
2755  * the features present and the RDONLY/RDWR mount requested.
2756  * Returns 1 if this filesystem can be mounted as requested,
2757  * 0 if it cannot be.
2758  */
2759 static int ext4_feature_set_ok(struct super_block *sb, int readonly)
2760 {
2761 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT4_FEATURE_INCOMPAT_SUPP)) {
2762 		ext4_msg(sb, KERN_ERR,
2763 			"Couldn't mount because of "
2764 			"unsupported optional features (%x)",
2765 			(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_incompat) &
2766 			~EXT4_FEATURE_INCOMPAT_SUPP));
2767 		return 0;
2768 	}
2769 
2770 	if (readonly)
2771 		return 1;
2772 
2773 	/* Check that feature set is OK for a read-write mount */
2774 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT4_FEATURE_RO_COMPAT_SUPP)) {
2775 		ext4_msg(sb, KERN_ERR, "couldn't mount RDWR because of "
2776 			 "unsupported optional features (%x)",
2777 			 (le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_ro_compat) &
2778 				~EXT4_FEATURE_RO_COMPAT_SUPP));
2779 		return 0;
2780 	}
2781 	/*
2782 	 * Large file size enabled file system can only be mounted
2783 	 * read-write on 32-bit systems if kernel is built with CONFIG_LBDAF
2784 	 */
2785 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
2786 		if (sizeof(blkcnt_t) < sizeof(u64)) {
2787 			ext4_msg(sb, KERN_ERR, "Filesystem with huge files "
2788 				 "cannot be mounted RDWR without "
2789 				 "CONFIG_LBDAF");
2790 			return 0;
2791 		}
2792 	}
2793 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_BIGALLOC) &&
2794 	    !EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
2795 		ext4_msg(sb, KERN_ERR,
2796 			 "Can't support bigalloc feature without "
2797 			 "extents feature\n");
2798 		return 0;
2799 	}
2800 
2801 #ifndef CONFIG_QUOTA
2802 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA) &&
2803 	    !readonly) {
2804 		ext4_msg(sb, KERN_ERR,
2805 			 "Filesystem with quota feature cannot be mounted RDWR "
2806 			 "without CONFIG_QUOTA");
2807 		return 0;
2808 	}
2809 #endif  /* CONFIG_QUOTA */
2810 	return 1;
2811 }
2812 
2813 /*
2814  * This function is called once a day if we have errors logged
2815  * on the file system
2816  */
2817 static void print_daily_error_info(unsigned long arg)
2818 {
2819 	struct super_block *sb = (struct super_block *) arg;
2820 	struct ext4_sb_info *sbi;
2821 	struct ext4_super_block *es;
2822 
2823 	sbi = EXT4_SB(sb);
2824 	es = sbi->s_es;
2825 
2826 	if (es->s_error_count)
2827 		/* fsck newer than v1.41.13 is needed to clean this condition. */
2828 		ext4_msg(sb, KERN_NOTICE, "error count since last fsck: %u",
2829 			 le32_to_cpu(es->s_error_count));
2830 	if (es->s_first_error_time) {
2831 		printk(KERN_NOTICE "EXT4-fs (%s): initial error at time %u: %.*s:%d",
2832 		       sb->s_id, le32_to_cpu(es->s_first_error_time),
2833 		       (int) sizeof(es->s_first_error_func),
2834 		       es->s_first_error_func,
2835 		       le32_to_cpu(es->s_first_error_line));
2836 		if (es->s_first_error_ino)
2837 			printk(": inode %u",
2838 			       le32_to_cpu(es->s_first_error_ino));
2839 		if (es->s_first_error_block)
2840 			printk(": block %llu", (unsigned long long)
2841 			       le64_to_cpu(es->s_first_error_block));
2842 		printk("\n");
2843 	}
2844 	if (es->s_last_error_time) {
2845 		printk(KERN_NOTICE "EXT4-fs (%s): last error at time %u: %.*s:%d",
2846 		       sb->s_id, le32_to_cpu(es->s_last_error_time),
2847 		       (int) sizeof(es->s_last_error_func),
2848 		       es->s_last_error_func,
2849 		       le32_to_cpu(es->s_last_error_line));
2850 		if (es->s_last_error_ino)
2851 			printk(": inode %u",
2852 			       le32_to_cpu(es->s_last_error_ino));
2853 		if (es->s_last_error_block)
2854 			printk(": block %llu", (unsigned long long)
2855 			       le64_to_cpu(es->s_last_error_block));
2856 		printk("\n");
2857 	}
2858 	mod_timer(&sbi->s_err_report, jiffies + 24*60*60*HZ);  /* Once a day */
2859 }
2860 
2861 /* Find next suitable group and run ext4_init_inode_table */
2862 static int ext4_run_li_request(struct ext4_li_request *elr)
2863 {
2864 	struct ext4_group_desc *gdp = NULL;
2865 	ext4_group_t group, ngroups;
2866 	struct super_block *sb;
2867 	unsigned long timeout = 0;
2868 	int ret = 0;
2869 
2870 	sb = elr->lr_super;
2871 	ngroups = EXT4_SB(sb)->s_groups_count;
2872 
2873 	sb_start_write(sb);
2874 	for (group = elr->lr_next_group; group < ngroups; group++) {
2875 		gdp = ext4_get_group_desc(sb, group, NULL);
2876 		if (!gdp) {
2877 			ret = 1;
2878 			break;
2879 		}
2880 
2881 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2882 			break;
2883 	}
2884 
2885 	if (group >= ngroups)
2886 		ret = 1;
2887 
2888 	if (!ret) {
2889 		timeout = jiffies;
2890 		ret = ext4_init_inode_table(sb, group,
2891 					    elr->lr_timeout ? 0 : 1);
2892 		if (elr->lr_timeout == 0) {
2893 			timeout = (jiffies - timeout) *
2894 				  elr->lr_sbi->s_li_wait_mult;
2895 			elr->lr_timeout = timeout;
2896 		}
2897 		elr->lr_next_sched = jiffies + elr->lr_timeout;
2898 		elr->lr_next_group = group + 1;
2899 	}
2900 	sb_end_write(sb);
2901 
2902 	return ret;
2903 }
2904 
2905 /*
2906  * Remove lr_request from the list_request and free the
2907  * request structure. Should be called with li_list_mtx held
2908  */
2909 static void ext4_remove_li_request(struct ext4_li_request *elr)
2910 {
2911 	struct ext4_sb_info *sbi;
2912 
2913 	if (!elr)
2914 		return;
2915 
2916 	sbi = elr->lr_sbi;
2917 
2918 	list_del(&elr->lr_request);
2919 	sbi->s_li_request = NULL;
2920 	kfree(elr);
2921 }
2922 
2923 static void ext4_unregister_li_request(struct super_block *sb)
2924 {
2925 	mutex_lock(&ext4_li_mtx);
2926 	if (!ext4_li_info) {
2927 		mutex_unlock(&ext4_li_mtx);
2928 		return;
2929 	}
2930 
2931 	mutex_lock(&ext4_li_info->li_list_mtx);
2932 	ext4_remove_li_request(EXT4_SB(sb)->s_li_request);
2933 	mutex_unlock(&ext4_li_info->li_list_mtx);
2934 	mutex_unlock(&ext4_li_mtx);
2935 }
2936 
2937 static struct task_struct *ext4_lazyinit_task;
2938 
2939 /*
2940  * This is the function where ext4lazyinit thread lives. It walks
2941  * through the request list searching for next scheduled filesystem.
2942  * When such a fs is found, run the lazy initialization request
2943  * (ext4_rn_li_request) and keep track of the time spend in this
2944  * function. Based on that time we compute next schedule time of
2945  * the request. When walking through the list is complete, compute
2946  * next waking time and put itself into sleep.
2947  */
2948 static int ext4_lazyinit_thread(void *arg)
2949 {
2950 	struct ext4_lazy_init *eli = (struct ext4_lazy_init *)arg;
2951 	struct list_head *pos, *n;
2952 	struct ext4_li_request *elr;
2953 	unsigned long next_wakeup, cur;
2954 
2955 	BUG_ON(NULL == eli);
2956 
2957 cont_thread:
2958 	while (true) {
2959 		next_wakeup = MAX_JIFFY_OFFSET;
2960 
2961 		mutex_lock(&eli->li_list_mtx);
2962 		if (list_empty(&eli->li_request_list)) {
2963 			mutex_unlock(&eli->li_list_mtx);
2964 			goto exit_thread;
2965 		}
2966 
2967 		list_for_each_safe(pos, n, &eli->li_request_list) {
2968 			elr = list_entry(pos, struct ext4_li_request,
2969 					 lr_request);
2970 
2971 			if (time_after_eq(jiffies, elr->lr_next_sched)) {
2972 				if (ext4_run_li_request(elr) != 0) {
2973 					/* error, remove the lazy_init job */
2974 					ext4_remove_li_request(elr);
2975 					continue;
2976 				}
2977 			}
2978 
2979 			if (time_before(elr->lr_next_sched, next_wakeup))
2980 				next_wakeup = elr->lr_next_sched;
2981 		}
2982 		mutex_unlock(&eli->li_list_mtx);
2983 
2984 		try_to_freeze();
2985 
2986 		cur = jiffies;
2987 		if ((time_after_eq(cur, next_wakeup)) ||
2988 		    (MAX_JIFFY_OFFSET == next_wakeup)) {
2989 			cond_resched();
2990 			continue;
2991 		}
2992 
2993 		schedule_timeout_interruptible(next_wakeup - cur);
2994 
2995 		if (kthread_should_stop()) {
2996 			ext4_clear_request_list();
2997 			goto exit_thread;
2998 		}
2999 	}
3000 
3001 exit_thread:
3002 	/*
3003 	 * It looks like the request list is empty, but we need
3004 	 * to check it under the li_list_mtx lock, to prevent any
3005 	 * additions into it, and of course we should lock ext4_li_mtx
3006 	 * to atomically free the list and ext4_li_info, because at
3007 	 * this point another ext4 filesystem could be registering
3008 	 * new one.
3009 	 */
3010 	mutex_lock(&ext4_li_mtx);
3011 	mutex_lock(&eli->li_list_mtx);
3012 	if (!list_empty(&eli->li_request_list)) {
3013 		mutex_unlock(&eli->li_list_mtx);
3014 		mutex_unlock(&ext4_li_mtx);
3015 		goto cont_thread;
3016 	}
3017 	mutex_unlock(&eli->li_list_mtx);
3018 	kfree(ext4_li_info);
3019 	ext4_li_info = NULL;
3020 	mutex_unlock(&ext4_li_mtx);
3021 
3022 	return 0;
3023 }
3024 
3025 static void ext4_clear_request_list(void)
3026 {
3027 	struct list_head *pos, *n;
3028 	struct ext4_li_request *elr;
3029 
3030 	mutex_lock(&ext4_li_info->li_list_mtx);
3031 	list_for_each_safe(pos, n, &ext4_li_info->li_request_list) {
3032 		elr = list_entry(pos, struct ext4_li_request,
3033 				 lr_request);
3034 		ext4_remove_li_request(elr);
3035 	}
3036 	mutex_unlock(&ext4_li_info->li_list_mtx);
3037 }
3038 
3039 static int ext4_run_lazyinit_thread(void)
3040 {
3041 	ext4_lazyinit_task = kthread_run(ext4_lazyinit_thread,
3042 					 ext4_li_info, "ext4lazyinit");
3043 	if (IS_ERR(ext4_lazyinit_task)) {
3044 		int err = PTR_ERR(ext4_lazyinit_task);
3045 		ext4_clear_request_list();
3046 		kfree(ext4_li_info);
3047 		ext4_li_info = NULL;
3048 		printk(KERN_CRIT "EXT4-fs: error %d creating inode table "
3049 				 "initialization thread\n",
3050 				 err);
3051 		return err;
3052 	}
3053 	ext4_li_info->li_state |= EXT4_LAZYINIT_RUNNING;
3054 	return 0;
3055 }
3056 
3057 /*
3058  * Check whether it make sense to run itable init. thread or not.
3059  * If there is at least one uninitialized inode table, return
3060  * corresponding group number, else the loop goes through all
3061  * groups and return total number of groups.
3062  */
3063 static ext4_group_t ext4_has_uninit_itable(struct super_block *sb)
3064 {
3065 	ext4_group_t group, ngroups = EXT4_SB(sb)->s_groups_count;
3066 	struct ext4_group_desc *gdp = NULL;
3067 
3068 	for (group = 0; group < ngroups; group++) {
3069 		gdp = ext4_get_group_desc(sb, group, NULL);
3070 		if (!gdp)
3071 			continue;
3072 
3073 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
3074 			break;
3075 	}
3076 
3077 	return group;
3078 }
3079 
3080 static int ext4_li_info_new(void)
3081 {
3082 	struct ext4_lazy_init *eli = NULL;
3083 
3084 	eli = kzalloc(sizeof(*eli), GFP_KERNEL);
3085 	if (!eli)
3086 		return -ENOMEM;
3087 
3088 	INIT_LIST_HEAD(&eli->li_request_list);
3089 	mutex_init(&eli->li_list_mtx);
3090 
3091 	eli->li_state |= EXT4_LAZYINIT_QUIT;
3092 
3093 	ext4_li_info = eli;
3094 
3095 	return 0;
3096 }
3097 
3098 static struct ext4_li_request *ext4_li_request_new(struct super_block *sb,
3099 					    ext4_group_t start)
3100 {
3101 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3102 	struct ext4_li_request *elr;
3103 
3104 	elr = kzalloc(sizeof(*elr), GFP_KERNEL);
3105 	if (!elr)
3106 		return NULL;
3107 
3108 	elr->lr_super = sb;
3109 	elr->lr_sbi = sbi;
3110 	elr->lr_next_group = start;
3111 
3112 	/*
3113 	 * Randomize first schedule time of the request to
3114 	 * spread the inode table initialization requests
3115 	 * better.
3116 	 */
3117 	elr->lr_next_sched = jiffies + (prandom_u32() %
3118 				(EXT4_DEF_LI_MAX_START_DELAY * HZ));
3119 	return elr;
3120 }
3121 
3122 int ext4_register_li_request(struct super_block *sb,
3123 			     ext4_group_t first_not_zeroed)
3124 {
3125 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3126 	struct ext4_li_request *elr = NULL;
3127 	ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
3128 	int ret = 0;
3129 
3130 	mutex_lock(&ext4_li_mtx);
3131 	if (sbi->s_li_request != NULL) {
3132 		/*
3133 		 * Reset timeout so it can be computed again, because
3134 		 * s_li_wait_mult might have changed.
3135 		 */
3136 		sbi->s_li_request->lr_timeout = 0;
3137 		goto out;
3138 	}
3139 
3140 	if (first_not_zeroed == ngroups ||
3141 	    (sb->s_flags & MS_RDONLY) ||
3142 	    !test_opt(sb, INIT_INODE_TABLE))
3143 		goto out;
3144 
3145 	elr = ext4_li_request_new(sb, first_not_zeroed);
3146 	if (!elr) {
3147 		ret = -ENOMEM;
3148 		goto out;
3149 	}
3150 
3151 	if (NULL == ext4_li_info) {
3152 		ret = ext4_li_info_new();
3153 		if (ret)
3154 			goto out;
3155 	}
3156 
3157 	mutex_lock(&ext4_li_info->li_list_mtx);
3158 	list_add(&elr->lr_request, &ext4_li_info->li_request_list);
3159 	mutex_unlock(&ext4_li_info->li_list_mtx);
3160 
3161 	sbi->s_li_request = elr;
3162 	/*
3163 	 * set elr to NULL here since it has been inserted to
3164 	 * the request_list and the removal and free of it is
3165 	 * handled by ext4_clear_request_list from now on.
3166 	 */
3167 	elr = NULL;
3168 
3169 	if (!(ext4_li_info->li_state & EXT4_LAZYINIT_RUNNING)) {
3170 		ret = ext4_run_lazyinit_thread();
3171 		if (ret)
3172 			goto out;
3173 	}
3174 out:
3175 	mutex_unlock(&ext4_li_mtx);
3176 	if (ret)
3177 		kfree(elr);
3178 	return ret;
3179 }
3180 
3181 /*
3182  * We do not need to lock anything since this is called on
3183  * module unload.
3184  */
3185 static void ext4_destroy_lazyinit_thread(void)
3186 {
3187 	/*
3188 	 * If thread exited earlier
3189 	 * there's nothing to be done.
3190 	 */
3191 	if (!ext4_li_info || !ext4_lazyinit_task)
3192 		return;
3193 
3194 	kthread_stop(ext4_lazyinit_task);
3195 }
3196 
3197 static int set_journal_csum_feature_set(struct super_block *sb)
3198 {
3199 	int ret = 1;
3200 	int compat, incompat;
3201 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3202 
3203 	if (ext4_has_metadata_csum(sb)) {
3204 		/* journal checksum v3 */
3205 		compat = 0;
3206 		incompat = JBD2_FEATURE_INCOMPAT_CSUM_V3;
3207 	} else {
3208 		/* journal checksum v1 */
3209 		compat = JBD2_FEATURE_COMPAT_CHECKSUM;
3210 		incompat = 0;
3211 	}
3212 
3213 	jbd2_journal_clear_features(sbi->s_journal,
3214 			JBD2_FEATURE_COMPAT_CHECKSUM, 0,
3215 			JBD2_FEATURE_INCOMPAT_CSUM_V3 |
3216 			JBD2_FEATURE_INCOMPAT_CSUM_V2);
3217 	if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
3218 		ret = jbd2_journal_set_features(sbi->s_journal,
3219 				compat, 0,
3220 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT |
3221 				incompat);
3222 	} else if (test_opt(sb, JOURNAL_CHECKSUM)) {
3223 		ret = jbd2_journal_set_features(sbi->s_journal,
3224 				compat, 0,
3225 				incompat);
3226 		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
3227 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
3228 	} else {
3229 		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
3230 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
3231 	}
3232 
3233 	return ret;
3234 }
3235 
3236 /*
3237  * Note: calculating the overhead so we can be compatible with
3238  * historical BSD practice is quite difficult in the face of
3239  * clusters/bigalloc.  This is because multiple metadata blocks from
3240  * different block group can end up in the same allocation cluster.
3241  * Calculating the exact overhead in the face of clustered allocation
3242  * requires either O(all block bitmaps) in memory or O(number of block
3243  * groups**2) in time.  We will still calculate the superblock for
3244  * older file systems --- and if we come across with a bigalloc file
3245  * system with zero in s_overhead_clusters the estimate will be close to
3246  * correct especially for very large cluster sizes --- but for newer
3247  * file systems, it's better to calculate this figure once at mkfs
3248  * time, and store it in the superblock.  If the superblock value is
3249  * present (even for non-bigalloc file systems), we will use it.
3250  */
3251 static int count_overhead(struct super_block *sb, ext4_group_t grp,
3252 			  char *buf)
3253 {
3254 	struct ext4_sb_info	*sbi = EXT4_SB(sb);
3255 	struct ext4_group_desc	*gdp;
3256 	ext4_fsblk_t		first_block, last_block, b;
3257 	ext4_group_t		i, ngroups = ext4_get_groups_count(sb);
3258 	int			s, j, count = 0;
3259 
3260 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_BIGALLOC))
3261 		return (ext4_bg_has_super(sb, grp) + ext4_bg_num_gdb(sb, grp) +
3262 			sbi->s_itb_per_group + 2);
3263 
3264 	first_block = le32_to_cpu(sbi->s_es->s_first_data_block) +
3265 		(grp * EXT4_BLOCKS_PER_GROUP(sb));
3266 	last_block = first_block + EXT4_BLOCKS_PER_GROUP(sb) - 1;
3267 	for (i = 0; i < ngroups; i++) {
3268 		gdp = ext4_get_group_desc(sb, i, NULL);
3269 		b = ext4_block_bitmap(sb, gdp);
3270 		if (b >= first_block && b <= last_block) {
3271 			ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf);
3272 			count++;
3273 		}
3274 		b = ext4_inode_bitmap(sb, gdp);
3275 		if (b >= first_block && b <= last_block) {
3276 			ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf);
3277 			count++;
3278 		}
3279 		b = ext4_inode_table(sb, gdp);
3280 		if (b >= first_block && b + sbi->s_itb_per_group <= last_block)
3281 			for (j = 0; j < sbi->s_itb_per_group; j++, b++) {
3282 				int c = EXT4_B2C(sbi, b - first_block);
3283 				ext4_set_bit(c, buf);
3284 				count++;
3285 			}
3286 		if (i != grp)
3287 			continue;
3288 		s = 0;
3289 		if (ext4_bg_has_super(sb, grp)) {
3290 			ext4_set_bit(s++, buf);
3291 			count++;
3292 		}
3293 		for (j = ext4_bg_num_gdb(sb, grp); j > 0; j--) {
3294 			ext4_set_bit(EXT4_B2C(sbi, s++), buf);
3295 			count++;
3296 		}
3297 	}
3298 	if (!count)
3299 		return 0;
3300 	return EXT4_CLUSTERS_PER_GROUP(sb) -
3301 		ext4_count_free(buf, EXT4_CLUSTERS_PER_GROUP(sb) / 8);
3302 }
3303 
3304 /*
3305  * Compute the overhead and stash it in sbi->s_overhead
3306  */
3307 int ext4_calculate_overhead(struct super_block *sb)
3308 {
3309 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3310 	struct ext4_super_block *es = sbi->s_es;
3311 	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
3312 	ext4_fsblk_t overhead = 0;
3313 	char *buf = (char *) get_zeroed_page(GFP_KERNEL);
3314 
3315 	if (!buf)
3316 		return -ENOMEM;
3317 
3318 	/*
3319 	 * Compute the overhead (FS structures).  This is constant
3320 	 * for a given filesystem unless the number of block groups
3321 	 * changes so we cache the previous value until it does.
3322 	 */
3323 
3324 	/*
3325 	 * All of the blocks before first_data_block are overhead
3326 	 */
3327 	overhead = EXT4_B2C(sbi, le32_to_cpu(es->s_first_data_block));
3328 
3329 	/*
3330 	 * Add the overhead found in each block group
3331 	 */
3332 	for (i = 0; i < ngroups; i++) {
3333 		int blks;
3334 
3335 		blks = count_overhead(sb, i, buf);
3336 		overhead += blks;
3337 		if (blks)
3338 			memset(buf, 0, PAGE_SIZE);
3339 		cond_resched();
3340 	}
3341 	/* Add the journal blocks as well */
3342 	if (sbi->s_journal)
3343 		overhead += EXT4_NUM_B2C(sbi, sbi->s_journal->j_maxlen);
3344 
3345 	sbi->s_overhead = overhead;
3346 	smp_wmb();
3347 	free_page((unsigned long) buf);
3348 	return 0;
3349 }
3350 
3351 
3352 static ext4_fsblk_t ext4_calculate_resv_clusters(struct super_block *sb)
3353 {
3354 	ext4_fsblk_t resv_clusters;
3355 
3356 	/*
3357 	 * There's no need to reserve anything when we aren't using extents.
3358 	 * The space estimates are exact, there are no unwritten extents,
3359 	 * hole punching doesn't need new metadata... This is needed especially
3360 	 * to keep ext2/3 backward compatibility.
3361 	 */
3362 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
3363 		return 0;
3364 	/*
3365 	 * By default we reserve 2% or 4096 clusters, whichever is smaller.
3366 	 * This should cover the situations where we can not afford to run
3367 	 * out of space like for example punch hole, or converting
3368 	 * unwritten extents in delalloc path. In most cases such
3369 	 * allocation would require 1, or 2 blocks, higher numbers are
3370 	 * very rare.
3371 	 */
3372 	resv_clusters = ext4_blocks_count(EXT4_SB(sb)->s_es) >>
3373 			EXT4_SB(sb)->s_cluster_bits;
3374 
3375 	do_div(resv_clusters, 50);
3376 	resv_clusters = min_t(ext4_fsblk_t, resv_clusters, 4096);
3377 
3378 	return resv_clusters;
3379 }
3380 
3381 
3382 static int ext4_reserve_clusters(struct ext4_sb_info *sbi, ext4_fsblk_t count)
3383 {
3384 	ext4_fsblk_t clusters = ext4_blocks_count(sbi->s_es) >>
3385 				sbi->s_cluster_bits;
3386 
3387 	if (count >= clusters)
3388 		return -EINVAL;
3389 
3390 	atomic64_set(&sbi->s_resv_clusters, count);
3391 	return 0;
3392 }
3393 
3394 static int ext4_fill_super(struct super_block *sb, void *data, int silent)
3395 {
3396 	char *orig_data = kstrdup(data, GFP_KERNEL);
3397 	struct buffer_head *bh;
3398 	struct ext4_super_block *es = NULL;
3399 	struct ext4_sb_info *sbi;
3400 	ext4_fsblk_t block;
3401 	ext4_fsblk_t sb_block = get_sb_block(&data);
3402 	ext4_fsblk_t logical_sb_block;
3403 	unsigned long offset = 0;
3404 	unsigned long journal_devnum = 0;
3405 	unsigned long def_mount_opts;
3406 	struct inode *root;
3407 	char *cp;
3408 	const char *descr;
3409 	int ret = -ENOMEM;
3410 	int blocksize, clustersize;
3411 	unsigned int db_count;
3412 	unsigned int i;
3413 	int needs_recovery, has_huge_files, has_bigalloc;
3414 	__u64 blocks_count;
3415 	int err = 0;
3416 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
3417 	ext4_group_t first_not_zeroed;
3418 
3419 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
3420 	if (!sbi)
3421 		goto out_free_orig;
3422 
3423 	sbi->s_blockgroup_lock =
3424 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
3425 	if (!sbi->s_blockgroup_lock) {
3426 		kfree(sbi);
3427 		goto out_free_orig;
3428 	}
3429 	sb->s_fs_info = sbi;
3430 	sbi->s_sb = sb;
3431 	sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
3432 	sbi->s_sb_block = sb_block;
3433 	if (sb->s_bdev->bd_part)
3434 		sbi->s_sectors_written_start =
3435 			part_stat_read(sb->s_bdev->bd_part, sectors[1]);
3436 
3437 	/* Cleanup superblock name */
3438 	for (cp = sb->s_id; (cp = strchr(cp, '/'));)
3439 		*cp = '!';
3440 
3441 	/* -EINVAL is default */
3442 	ret = -EINVAL;
3443 	blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
3444 	if (!blocksize) {
3445 		ext4_msg(sb, KERN_ERR, "unable to set blocksize");
3446 		goto out_fail;
3447 	}
3448 
3449 	/*
3450 	 * The ext4 superblock will not be buffer aligned for other than 1kB
3451 	 * block sizes.  We need to calculate the offset from buffer start.
3452 	 */
3453 	if (blocksize != EXT4_MIN_BLOCK_SIZE) {
3454 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3455 		offset = do_div(logical_sb_block, blocksize);
3456 	} else {
3457 		logical_sb_block = sb_block;
3458 	}
3459 
3460 	if (!(bh = sb_bread_unmovable(sb, logical_sb_block))) {
3461 		ext4_msg(sb, KERN_ERR, "unable to read superblock");
3462 		goto out_fail;
3463 	}
3464 	/*
3465 	 * Note: s_es must be initialized as soon as possible because
3466 	 *       some ext4 macro-instructions depend on its value
3467 	 */
3468 	es = (struct ext4_super_block *) (bh->b_data + offset);
3469 	sbi->s_es = es;
3470 	sb->s_magic = le16_to_cpu(es->s_magic);
3471 	if (sb->s_magic != EXT4_SUPER_MAGIC)
3472 		goto cantfind_ext4;
3473 	sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
3474 
3475 	/* Warn if metadata_csum and gdt_csum are both set. */
3476 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3477 				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
3478 	    EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
3479 		ext4_warning(sb, KERN_INFO "metadata_csum and uninit_bg are "
3480 			     "redundant flags; please run fsck.");
3481 
3482 	/* Check for a known checksum algorithm */
3483 	if (!ext4_verify_csum_type(sb, es)) {
3484 		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
3485 			 "unknown checksum algorithm.");
3486 		silent = 1;
3487 		goto cantfind_ext4;
3488 	}
3489 
3490 	/* Load the checksum driver */
3491 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3492 				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
3493 		sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
3494 		if (IS_ERR(sbi->s_chksum_driver)) {
3495 			ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
3496 			ret = PTR_ERR(sbi->s_chksum_driver);
3497 			sbi->s_chksum_driver = NULL;
3498 			goto failed_mount;
3499 		}
3500 	}
3501 
3502 	/* Check superblock checksum */
3503 	if (!ext4_superblock_csum_verify(sb, es)) {
3504 		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
3505 			 "invalid superblock checksum.  Run e2fsck?");
3506 		silent = 1;
3507 		goto cantfind_ext4;
3508 	}
3509 
3510 	/* Precompute checksum seed for all metadata */
3511 	if (ext4_has_metadata_csum(sb))
3512 		sbi->s_csum_seed = ext4_chksum(sbi, ~0, es->s_uuid,
3513 					       sizeof(es->s_uuid));
3514 
3515 	/* Set defaults before we parse the mount options */
3516 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
3517 	set_opt(sb, INIT_INODE_TABLE);
3518 	if (def_mount_opts & EXT4_DEFM_DEBUG)
3519 		set_opt(sb, DEBUG);
3520 	if (def_mount_opts & EXT4_DEFM_BSDGROUPS)
3521 		set_opt(sb, GRPID);
3522 	if (def_mount_opts & EXT4_DEFM_UID16)
3523 		set_opt(sb, NO_UID32);
3524 	/* xattr user namespace & acls are now defaulted on */
3525 	set_opt(sb, XATTR_USER);
3526 #ifdef CONFIG_EXT4_FS_POSIX_ACL
3527 	set_opt(sb, POSIX_ACL);
3528 #endif
3529 	/* don't forget to enable journal_csum when metadata_csum is enabled. */
3530 	if (ext4_has_metadata_csum(sb))
3531 		set_opt(sb, JOURNAL_CHECKSUM);
3532 
3533 	if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA)
3534 		set_opt(sb, JOURNAL_DATA);
3535 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_ORDERED)
3536 		set_opt(sb, ORDERED_DATA);
3537 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_WBACK)
3538 		set_opt(sb, WRITEBACK_DATA);
3539 
3540 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_PANIC)
3541 		set_opt(sb, ERRORS_PANIC);
3542 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_CONTINUE)
3543 		set_opt(sb, ERRORS_CONT);
3544 	else
3545 		set_opt(sb, ERRORS_RO);
3546 	/* block_validity enabled by default; disable with noblock_validity */
3547 	set_opt(sb, BLOCK_VALIDITY);
3548 	if (def_mount_opts & EXT4_DEFM_DISCARD)
3549 		set_opt(sb, DISCARD);
3550 
3551 	sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
3552 	sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
3553 	sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ;
3554 	sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;
3555 	sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;
3556 
3557 	if ((def_mount_opts & EXT4_DEFM_NOBARRIER) == 0)
3558 		set_opt(sb, BARRIER);
3559 
3560 	/*
3561 	 * enable delayed allocation by default
3562 	 * Use -o nodelalloc to turn it off
3563 	 */
3564 	if (!IS_EXT3_SB(sb) && !IS_EXT2_SB(sb) &&
3565 	    ((def_mount_opts & EXT4_DEFM_NODELALLOC) == 0))
3566 		set_opt(sb, DELALLOC);
3567 
3568 	/*
3569 	 * set default s_li_wait_mult for lazyinit, for the case there is
3570 	 * no mount option specified.
3571 	 */
3572 	sbi->s_li_wait_mult = EXT4_DEF_LI_WAIT_MULT;
3573 
3574 	if (!parse_options((char *) sbi->s_es->s_mount_opts, sb,
3575 			   &journal_devnum, &journal_ioprio, 0)) {
3576 		ext4_msg(sb, KERN_WARNING,
3577 			 "failed to parse options in superblock: %s",
3578 			 sbi->s_es->s_mount_opts);
3579 	}
3580 	sbi->s_def_mount_opt = sbi->s_mount_opt;
3581 	if (!parse_options((char *) data, sb, &journal_devnum,
3582 			   &journal_ioprio, 0))
3583 		goto failed_mount;
3584 
3585 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
3586 		printk_once(KERN_WARNING "EXT4-fs: Warning: mounting "
3587 			    "with data=journal disables delayed "
3588 			    "allocation and O_DIRECT support!\n");
3589 		if (test_opt2(sb, EXPLICIT_DELALLOC)) {
3590 			ext4_msg(sb, KERN_ERR, "can't mount with "
3591 				 "both data=journal and delalloc");
3592 			goto failed_mount;
3593 		}
3594 		if (test_opt(sb, DIOREAD_NOLOCK)) {
3595 			ext4_msg(sb, KERN_ERR, "can't mount with "
3596 				 "both data=journal and dioread_nolock");
3597 			goto failed_mount;
3598 		}
3599 		if (test_opt(sb, DELALLOC))
3600 			clear_opt(sb, DELALLOC);
3601 	}
3602 
3603 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
3604 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
3605 
3606 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
3607 	    (EXT4_HAS_COMPAT_FEATURE(sb, ~0U) ||
3608 	     EXT4_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
3609 	     EXT4_HAS_INCOMPAT_FEATURE(sb, ~0U)))
3610 		ext4_msg(sb, KERN_WARNING,
3611 		       "feature flags set on rev 0 fs, "
3612 		       "running e2fsck is recommended");
3613 
3614 	if (es->s_creator_os == cpu_to_le32(EXT4_OS_HURD)) {
3615 		set_opt2(sb, HURD_COMPAT);
3616 		if (EXT4_HAS_INCOMPAT_FEATURE(sb,
3617 					      EXT4_FEATURE_INCOMPAT_64BIT)) {
3618 			ext4_msg(sb, KERN_ERR,
3619 				 "The Hurd can't support 64-bit file systems");
3620 			goto failed_mount;
3621 		}
3622 	}
3623 
3624 	if (IS_EXT2_SB(sb)) {
3625 		if (ext2_feature_set_ok(sb))
3626 			ext4_msg(sb, KERN_INFO, "mounting ext2 file system "
3627 				 "using the ext4 subsystem");
3628 		else {
3629 			ext4_msg(sb, KERN_ERR, "couldn't mount as ext2 due "
3630 				 "to feature incompatibilities");
3631 			goto failed_mount;
3632 		}
3633 	}
3634 
3635 	if (IS_EXT3_SB(sb)) {
3636 		if (ext3_feature_set_ok(sb))
3637 			ext4_msg(sb, KERN_INFO, "mounting ext3 file system "
3638 				 "using the ext4 subsystem");
3639 		else {
3640 			ext4_msg(sb, KERN_ERR, "couldn't mount as ext3 due "
3641 				 "to feature incompatibilities");
3642 			goto failed_mount;
3643 		}
3644 	}
3645 
3646 	/*
3647 	 * Check feature flags regardless of the revision level, since we
3648 	 * previously didn't change the revision level when setting the flags,
3649 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
3650 	 */
3651 	if (!ext4_feature_set_ok(sb, (sb->s_flags & MS_RDONLY)))
3652 		goto failed_mount;
3653 
3654 	blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
3655 	if (blocksize < EXT4_MIN_BLOCK_SIZE ||
3656 	    blocksize > EXT4_MAX_BLOCK_SIZE) {
3657 		ext4_msg(sb, KERN_ERR,
3658 		       "Unsupported filesystem blocksize %d", blocksize);
3659 		goto failed_mount;
3660 	}
3661 
3662 	if (sb->s_blocksize != blocksize) {
3663 		/* Validate the filesystem blocksize */
3664 		if (!sb_set_blocksize(sb, blocksize)) {
3665 			ext4_msg(sb, KERN_ERR, "bad block size %d",
3666 					blocksize);
3667 			goto failed_mount;
3668 		}
3669 
3670 		brelse(bh);
3671 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3672 		offset = do_div(logical_sb_block, blocksize);
3673 		bh = sb_bread_unmovable(sb, logical_sb_block);
3674 		if (!bh) {
3675 			ext4_msg(sb, KERN_ERR,
3676 			       "Can't read superblock on 2nd try");
3677 			goto failed_mount;
3678 		}
3679 		es = (struct ext4_super_block *)(bh->b_data + offset);
3680 		sbi->s_es = es;
3681 		if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
3682 			ext4_msg(sb, KERN_ERR,
3683 			       "Magic mismatch, very weird!");
3684 			goto failed_mount;
3685 		}
3686 	}
3687 
3688 	has_huge_files = EXT4_HAS_RO_COMPAT_FEATURE(sb,
3689 				EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
3690 	sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits,
3691 						      has_huge_files);
3692 	sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits, has_huge_files);
3693 
3694 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) {
3695 		sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE;
3696 		sbi->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
3697 	} else {
3698 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
3699 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
3700 		if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
3701 		    (!is_power_of_2(sbi->s_inode_size)) ||
3702 		    (sbi->s_inode_size > blocksize)) {
3703 			ext4_msg(sb, KERN_ERR,
3704 			       "unsupported inode size: %d",
3705 			       sbi->s_inode_size);
3706 			goto failed_mount;
3707 		}
3708 		if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE)
3709 			sb->s_time_gran = 1 << (EXT4_EPOCH_BITS - 2);
3710 	}
3711 
3712 	sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
3713 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT)) {
3714 		if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT ||
3715 		    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
3716 		    !is_power_of_2(sbi->s_desc_size)) {
3717 			ext4_msg(sb, KERN_ERR,
3718 			       "unsupported descriptor size %lu",
3719 			       sbi->s_desc_size);
3720 			goto failed_mount;
3721 		}
3722 	} else
3723 		sbi->s_desc_size = EXT4_MIN_DESC_SIZE;
3724 
3725 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
3726 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
3727 	if (EXT4_INODE_SIZE(sb) == 0 || EXT4_INODES_PER_GROUP(sb) == 0)
3728 		goto cantfind_ext4;
3729 
3730 	sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
3731 	if (sbi->s_inodes_per_block == 0)
3732 		goto cantfind_ext4;
3733 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
3734 					sbi->s_inodes_per_block;
3735 	sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
3736 	sbi->s_sbh = bh;
3737 	sbi->s_mount_state = le16_to_cpu(es->s_state);
3738 	sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
3739 	sbi->s_desc_per_block_bits = ilog2(EXT4_DESC_PER_BLOCK(sb));
3740 
3741 	for (i = 0; i < 4; i++)
3742 		sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
3743 	sbi->s_def_hash_version = es->s_def_hash_version;
3744 	if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_DIR_INDEX)) {
3745 		i = le32_to_cpu(es->s_flags);
3746 		if (i & EXT2_FLAGS_UNSIGNED_HASH)
3747 			sbi->s_hash_unsigned = 3;
3748 		else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) {
3749 #ifdef __CHAR_UNSIGNED__
3750 			if (!(sb->s_flags & MS_RDONLY))
3751 				es->s_flags |=
3752 					cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH);
3753 			sbi->s_hash_unsigned = 3;
3754 #else
3755 			if (!(sb->s_flags & MS_RDONLY))
3756 				es->s_flags |=
3757 					cpu_to_le32(EXT2_FLAGS_SIGNED_HASH);
3758 #endif
3759 		}
3760 	}
3761 
3762 	/* Handle clustersize */
3763 	clustersize = BLOCK_SIZE << le32_to_cpu(es->s_log_cluster_size);
3764 	has_bigalloc = EXT4_HAS_RO_COMPAT_FEATURE(sb,
3765 				EXT4_FEATURE_RO_COMPAT_BIGALLOC);
3766 	if (has_bigalloc) {
3767 		if (clustersize < blocksize) {
3768 			ext4_msg(sb, KERN_ERR,
3769 				 "cluster size (%d) smaller than "
3770 				 "block size (%d)", clustersize, blocksize);
3771 			goto failed_mount;
3772 		}
3773 		sbi->s_cluster_bits = le32_to_cpu(es->s_log_cluster_size) -
3774 			le32_to_cpu(es->s_log_block_size);
3775 		sbi->s_clusters_per_group =
3776 			le32_to_cpu(es->s_clusters_per_group);
3777 		if (sbi->s_clusters_per_group > blocksize * 8) {
3778 			ext4_msg(sb, KERN_ERR,
3779 				 "#clusters per group too big: %lu",
3780 				 sbi->s_clusters_per_group);
3781 			goto failed_mount;
3782 		}
3783 		if (sbi->s_blocks_per_group !=
3784 		    (sbi->s_clusters_per_group * (clustersize / blocksize))) {
3785 			ext4_msg(sb, KERN_ERR, "blocks per group (%lu) and "
3786 				 "clusters per group (%lu) inconsistent",
3787 				 sbi->s_blocks_per_group,
3788 				 sbi->s_clusters_per_group);
3789 			goto failed_mount;
3790 		}
3791 	} else {
3792 		if (clustersize != blocksize) {
3793 			ext4_warning(sb, "fragment/cluster size (%d) != "
3794 				     "block size (%d)", clustersize,
3795 				     blocksize);
3796 			clustersize = blocksize;
3797 		}
3798 		if (sbi->s_blocks_per_group > blocksize * 8) {
3799 			ext4_msg(sb, KERN_ERR,
3800 				 "#blocks per group too big: %lu",
3801 				 sbi->s_blocks_per_group);
3802 			goto failed_mount;
3803 		}
3804 		sbi->s_clusters_per_group = sbi->s_blocks_per_group;
3805 		sbi->s_cluster_bits = 0;
3806 	}
3807 	sbi->s_cluster_ratio = clustersize / blocksize;
3808 
3809 	if (sbi->s_inodes_per_group > blocksize * 8) {
3810 		ext4_msg(sb, KERN_ERR,
3811 		       "#inodes per group too big: %lu",
3812 		       sbi->s_inodes_per_group);
3813 		goto failed_mount;
3814 	}
3815 
3816 	/* Do we have standard group size of clustersize * 8 blocks ? */
3817 	if (sbi->s_blocks_per_group == clustersize << 3)
3818 		set_opt2(sb, STD_GROUP_SIZE);
3819 
3820 	/*
3821 	 * Test whether we have more sectors than will fit in sector_t,
3822 	 * and whether the max offset is addressable by the page cache.
3823 	 */
3824 	err = generic_check_addressable(sb->s_blocksize_bits,
3825 					ext4_blocks_count(es));
3826 	if (err) {
3827 		ext4_msg(sb, KERN_ERR, "filesystem"
3828 			 " too large to mount safely on this system");
3829 		if (sizeof(sector_t) < 8)
3830 			ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled");
3831 		goto failed_mount;
3832 	}
3833 
3834 	if (EXT4_BLOCKS_PER_GROUP(sb) == 0)
3835 		goto cantfind_ext4;
3836 
3837 	/* check blocks count against device size */
3838 	blocks_count = sb->s_bdev->bd_inode->i_size >> sb->s_blocksize_bits;
3839 	if (blocks_count && ext4_blocks_count(es) > blocks_count) {
3840 		ext4_msg(sb, KERN_WARNING, "bad geometry: block count %llu "
3841 		       "exceeds size of device (%llu blocks)",
3842 		       ext4_blocks_count(es), blocks_count);
3843 		goto failed_mount;
3844 	}
3845 
3846 	/*
3847 	 * It makes no sense for the first data block to be beyond the end
3848 	 * of the filesystem.
3849 	 */
3850 	if (le32_to_cpu(es->s_first_data_block) >= ext4_blocks_count(es)) {
3851 		ext4_msg(sb, KERN_WARNING, "bad geometry: first data "
3852 			 "block %u is beyond end of filesystem (%llu)",
3853 			 le32_to_cpu(es->s_first_data_block),
3854 			 ext4_blocks_count(es));
3855 		goto failed_mount;
3856 	}
3857 	blocks_count = (ext4_blocks_count(es) -
3858 			le32_to_cpu(es->s_first_data_block) +
3859 			EXT4_BLOCKS_PER_GROUP(sb) - 1);
3860 	do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
3861 	if (blocks_count > ((uint64_t)1<<32) - EXT4_DESC_PER_BLOCK(sb)) {
3862 		ext4_msg(sb, KERN_WARNING, "groups count too large: %u "
3863 		       "(block count %llu, first data block %u, "
3864 		       "blocks per group %lu)", sbi->s_groups_count,
3865 		       ext4_blocks_count(es),
3866 		       le32_to_cpu(es->s_first_data_block),
3867 		       EXT4_BLOCKS_PER_GROUP(sb));
3868 		goto failed_mount;
3869 	}
3870 	sbi->s_groups_count = blocks_count;
3871 	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
3872 			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
3873 	db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
3874 		   EXT4_DESC_PER_BLOCK(sb);
3875 	sbi->s_group_desc = ext4_kvmalloc(db_count *
3876 					  sizeof(struct buffer_head *),
3877 					  GFP_KERNEL);
3878 	if (sbi->s_group_desc == NULL) {
3879 		ext4_msg(sb, KERN_ERR, "not enough memory");
3880 		ret = -ENOMEM;
3881 		goto failed_mount;
3882 	}
3883 
3884 	if (ext4_proc_root)
3885 		sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
3886 
3887 	if (sbi->s_proc)
3888 		proc_create_data("options", S_IRUGO, sbi->s_proc,
3889 				 &ext4_seq_options_fops, sb);
3890 
3891 	bgl_lock_init(sbi->s_blockgroup_lock);
3892 
3893 	for (i = 0; i < db_count; i++) {
3894 		block = descriptor_loc(sb, logical_sb_block, i);
3895 		sbi->s_group_desc[i] = sb_bread_unmovable(sb, block);
3896 		if (!sbi->s_group_desc[i]) {
3897 			ext4_msg(sb, KERN_ERR,
3898 			       "can't read group descriptor %d", i);
3899 			db_count = i;
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_mount2;
3906 	}
3907 
3908 	sbi->s_gdb_count = db_count;
3909 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
3910 	spin_lock_init(&sbi->s_next_gen_lock);
3911 
3912 	init_timer(&sbi->s_err_report);
3913 	sbi->s_err_report.function = print_daily_error_info;
3914 	sbi->s_err_report.data = (unsigned long) sb;
3915 
3916 	/* Register extent status tree shrinker */
3917 	if (ext4_es_register_shrinker(sbi))
3918 		goto failed_mount3;
3919 
3920 	sbi->s_stripe = ext4_get_stripe_size(sbi);
3921 	sbi->s_extent_max_zeroout_kb = 32;
3922 
3923 	/*
3924 	 * set up enough so that it can read an inode
3925 	 */
3926 	sb->s_op = &ext4_sops;
3927 	sb->s_export_op = &ext4_export_ops;
3928 	sb->s_xattr = ext4_xattr_handlers;
3929 #ifdef CONFIG_QUOTA
3930 	sb->dq_op = &ext4_quota_operations;
3931 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA))
3932 		sb->s_qcop = &ext4_qctl_sysfile_operations;
3933 	else
3934 		sb->s_qcop = &ext4_qctl_operations;
3935 #endif
3936 	memcpy(sb->s_uuid, es->s_uuid, sizeof(es->s_uuid));
3937 
3938 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
3939 	mutex_init(&sbi->s_orphan_lock);
3940 
3941 	sb->s_root = NULL;
3942 
3943 	needs_recovery = (es->s_last_orphan != 0 ||
3944 			  EXT4_HAS_INCOMPAT_FEATURE(sb,
3945 				    EXT4_FEATURE_INCOMPAT_RECOVER));
3946 
3947 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_MMP) &&
3948 	    !(sb->s_flags & MS_RDONLY))
3949 		if (ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block)))
3950 			goto failed_mount3a;
3951 
3952 	/*
3953 	 * The first inode we look at is the journal inode.  Don't try
3954 	 * root first: it may be modified in the journal!
3955 	 */
3956 	if (!test_opt(sb, NOLOAD) &&
3957 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
3958 		if (ext4_load_journal(sb, es, journal_devnum))
3959 			goto failed_mount3a;
3960 	} else if (test_opt(sb, NOLOAD) && !(sb->s_flags & MS_RDONLY) &&
3961 	      EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
3962 		ext4_msg(sb, KERN_ERR, "required journal recovery "
3963 		       "suppressed and not mounted read-only");
3964 		goto failed_mount_wq;
3965 	} else {
3966 		clear_opt(sb, DATA_FLAGS);
3967 		sbi->s_journal = NULL;
3968 		needs_recovery = 0;
3969 		goto no_journal;
3970 	}
3971 
3972 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT) &&
3973 	    !jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
3974 				       JBD2_FEATURE_INCOMPAT_64BIT)) {
3975 		ext4_msg(sb, KERN_ERR, "Failed to set 64-bit journal feature");
3976 		goto failed_mount_wq;
3977 	}
3978 
3979 	if (!set_journal_csum_feature_set(sb)) {
3980 		ext4_msg(sb, KERN_ERR, "Failed to set journal checksum "
3981 			 "feature set");
3982 		goto failed_mount_wq;
3983 	}
3984 
3985 	/* We have now updated the journal if required, so we can
3986 	 * validate the data journaling mode. */
3987 	switch (test_opt(sb, DATA_FLAGS)) {
3988 	case 0:
3989 		/* No mode set, assume a default based on the journal
3990 		 * capabilities: ORDERED_DATA if the journal can
3991 		 * cope, else JOURNAL_DATA
3992 		 */
3993 		if (jbd2_journal_check_available_features
3994 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE))
3995 			set_opt(sb, ORDERED_DATA);
3996 		else
3997 			set_opt(sb, JOURNAL_DATA);
3998 		break;
3999 
4000 	case EXT4_MOUNT_ORDERED_DATA:
4001 	case EXT4_MOUNT_WRITEBACK_DATA:
4002 		if (!jbd2_journal_check_available_features
4003 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
4004 			ext4_msg(sb, KERN_ERR, "Journal does not support "
4005 			       "requested data journaling mode");
4006 			goto failed_mount_wq;
4007 		}
4008 	default:
4009 		break;
4010 	}
4011 	set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
4012 
4013 	sbi->s_journal->j_commit_callback = ext4_journal_commit_callback;
4014 
4015 no_journal:
4016 	if (ext4_mballoc_ready) {
4017 		sbi->s_mb_cache = ext4_xattr_create_cache(sb->s_id);
4018 		if (!sbi->s_mb_cache) {
4019 			ext4_msg(sb, KERN_ERR, "Failed to create an mb_cache");
4020 			goto failed_mount_wq;
4021 		}
4022 	}
4023 
4024 	/*
4025 	 * Get the # of file system overhead blocks from the
4026 	 * superblock if present.
4027 	 */
4028 	if (es->s_overhead_clusters)
4029 		sbi->s_overhead = le32_to_cpu(es->s_overhead_clusters);
4030 	else {
4031 		err = ext4_calculate_overhead(sb);
4032 		if (err)
4033 			goto failed_mount_wq;
4034 	}
4035 
4036 	/*
4037 	 * The maximum number of concurrent works can be high and
4038 	 * concurrency isn't really necessary.  Limit it to 1.
4039 	 */
4040 	EXT4_SB(sb)->rsv_conversion_wq =
4041 		alloc_workqueue("ext4-rsv-conversion", WQ_MEM_RECLAIM | WQ_UNBOUND, 1);
4042 	if (!EXT4_SB(sb)->rsv_conversion_wq) {
4043 		printk(KERN_ERR "EXT4-fs: failed to create workqueue\n");
4044 		ret = -ENOMEM;
4045 		goto failed_mount4;
4046 	}
4047 
4048 	/*
4049 	 * The jbd2_journal_load will have done any necessary log recovery,
4050 	 * so we can safely mount the rest of the filesystem now.
4051 	 */
4052 
4053 	root = ext4_iget(sb, EXT4_ROOT_INO);
4054 	if (IS_ERR(root)) {
4055 		ext4_msg(sb, KERN_ERR, "get root inode failed");
4056 		ret = PTR_ERR(root);
4057 		root = NULL;
4058 		goto failed_mount4;
4059 	}
4060 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
4061 		ext4_msg(sb, KERN_ERR, "corrupt root inode, run e2fsck");
4062 		iput(root);
4063 		goto failed_mount4;
4064 	}
4065 	sb->s_root = d_make_root(root);
4066 	if (!sb->s_root) {
4067 		ext4_msg(sb, KERN_ERR, "get root dentry failed");
4068 		ret = -ENOMEM;
4069 		goto failed_mount4;
4070 	}
4071 
4072 	if (ext4_setup_super(sb, es, sb->s_flags & MS_RDONLY))
4073 		sb->s_flags |= MS_RDONLY;
4074 
4075 	/* determine the minimum size of new large inodes, if present */
4076 	if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
4077 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
4078 						     EXT4_GOOD_OLD_INODE_SIZE;
4079 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
4080 				       EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE)) {
4081 			if (sbi->s_want_extra_isize <
4082 			    le16_to_cpu(es->s_want_extra_isize))
4083 				sbi->s_want_extra_isize =
4084 					le16_to_cpu(es->s_want_extra_isize);
4085 			if (sbi->s_want_extra_isize <
4086 			    le16_to_cpu(es->s_min_extra_isize))
4087 				sbi->s_want_extra_isize =
4088 					le16_to_cpu(es->s_min_extra_isize);
4089 		}
4090 	}
4091 	/* Check if enough inode space is available */
4092 	if (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize >
4093 							sbi->s_inode_size) {
4094 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
4095 						       EXT4_GOOD_OLD_INODE_SIZE;
4096 		ext4_msg(sb, KERN_INFO, "required extra inode space not"
4097 			 "available");
4098 	}
4099 
4100 	err = ext4_reserve_clusters(sbi, ext4_calculate_resv_clusters(sb));
4101 	if (err) {
4102 		ext4_msg(sb, KERN_ERR, "failed to reserve %llu clusters for "
4103 			 "reserved pool", ext4_calculate_resv_clusters(sb));
4104 		goto failed_mount4a;
4105 	}
4106 
4107 	err = ext4_setup_system_zone(sb);
4108 	if (err) {
4109 		ext4_msg(sb, KERN_ERR, "failed to initialize system "
4110 			 "zone (%d)", err);
4111 		goto failed_mount4a;
4112 	}
4113 
4114 	ext4_ext_init(sb);
4115 	err = ext4_mb_init(sb);
4116 	if (err) {
4117 		ext4_msg(sb, KERN_ERR, "failed to initialize mballoc (%d)",
4118 			 err);
4119 		goto failed_mount5;
4120 	}
4121 
4122 	block = ext4_count_free_clusters(sb);
4123 	ext4_free_blocks_count_set(sbi->s_es,
4124 				   EXT4_C2B(sbi, block));
4125 	err = percpu_counter_init(&sbi->s_freeclusters_counter, block,
4126 				  GFP_KERNEL);
4127 	if (!err) {
4128 		unsigned long freei = ext4_count_free_inodes(sb);
4129 		sbi->s_es->s_free_inodes_count = cpu_to_le32(freei);
4130 		err = percpu_counter_init(&sbi->s_freeinodes_counter, freei,
4131 					  GFP_KERNEL);
4132 	}
4133 	if (!err)
4134 		err = percpu_counter_init(&sbi->s_dirs_counter,
4135 					  ext4_count_dirs(sb), GFP_KERNEL);
4136 	if (!err)
4137 		err = percpu_counter_init(&sbi->s_dirtyclusters_counter, 0,
4138 					  GFP_KERNEL);
4139 	if (err) {
4140 		ext4_msg(sb, KERN_ERR, "insufficient memory");
4141 		goto failed_mount6;
4142 	}
4143 
4144 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
4145 		if (!ext4_fill_flex_info(sb)) {
4146 			ext4_msg(sb, KERN_ERR,
4147 			       "unable to initialize "
4148 			       "flex_bg meta info!");
4149 			goto failed_mount6;
4150 		}
4151 
4152 	err = ext4_register_li_request(sb, first_not_zeroed);
4153 	if (err)
4154 		goto failed_mount6;
4155 
4156 	sbi->s_kobj.kset = ext4_kset;
4157 	init_completion(&sbi->s_kobj_unregister);
4158 	err = kobject_init_and_add(&sbi->s_kobj, &ext4_ktype, NULL,
4159 				   "%s", sb->s_id);
4160 	if (err)
4161 		goto failed_mount7;
4162 
4163 #ifdef CONFIG_QUOTA
4164 	/* Enable quota usage during mount. */
4165 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA) &&
4166 	    !(sb->s_flags & MS_RDONLY)) {
4167 		err = ext4_enable_quotas(sb);
4168 		if (err)
4169 			goto failed_mount8;
4170 	}
4171 #endif  /* CONFIG_QUOTA */
4172 
4173 	EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
4174 	ext4_orphan_cleanup(sb, es);
4175 	EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
4176 	if (needs_recovery) {
4177 		ext4_msg(sb, KERN_INFO, "recovery complete");
4178 		ext4_mark_recovery_complete(sb, es);
4179 	}
4180 	if (EXT4_SB(sb)->s_journal) {
4181 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
4182 			descr = " journalled data mode";
4183 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
4184 			descr = " ordered data mode";
4185 		else
4186 			descr = " writeback data mode";
4187 	} else
4188 		descr = "out journal";
4189 
4190 	if (test_opt(sb, DISCARD)) {
4191 		struct request_queue *q = bdev_get_queue(sb->s_bdev);
4192 		if (!blk_queue_discard(q))
4193 			ext4_msg(sb, KERN_WARNING,
4194 				 "mounting with \"discard\" option, but "
4195 				 "the device does not support discard");
4196 	}
4197 
4198 	ext4_msg(sb, KERN_INFO, "mounted filesystem with%s. "
4199 		 "Opts: %s%s%s", descr, sbi->s_es->s_mount_opts,
4200 		 *sbi->s_es->s_mount_opts ? "; " : "", orig_data);
4201 
4202 	if (es->s_error_count)
4203 		mod_timer(&sbi->s_err_report, jiffies + 300*HZ); /* 5 minutes */
4204 
4205 	/* Enable message ratelimiting. Default is 10 messages per 5 secs. */
4206 	ratelimit_state_init(&sbi->s_err_ratelimit_state, 5 * HZ, 10);
4207 	ratelimit_state_init(&sbi->s_warning_ratelimit_state, 5 * HZ, 10);
4208 	ratelimit_state_init(&sbi->s_msg_ratelimit_state, 5 * HZ, 10);
4209 
4210 	kfree(orig_data);
4211 	return 0;
4212 
4213 cantfind_ext4:
4214 	if (!silent)
4215 		ext4_msg(sb, KERN_ERR, "VFS: Can't find ext4 filesystem");
4216 	goto failed_mount;
4217 
4218 #ifdef CONFIG_QUOTA
4219 failed_mount8:
4220 	kobject_del(&sbi->s_kobj);
4221 #endif
4222 failed_mount7:
4223 	ext4_unregister_li_request(sb);
4224 failed_mount6:
4225 	ext4_mb_release(sb);
4226 	if (sbi->s_flex_groups)
4227 		ext4_kvfree(sbi->s_flex_groups);
4228 	percpu_counter_destroy(&sbi->s_freeclusters_counter);
4229 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
4230 	percpu_counter_destroy(&sbi->s_dirs_counter);
4231 	percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
4232 failed_mount5:
4233 	ext4_ext_release(sb);
4234 	ext4_release_system_zone(sb);
4235 failed_mount4a:
4236 	dput(sb->s_root);
4237 	sb->s_root = NULL;
4238 failed_mount4:
4239 	ext4_msg(sb, KERN_ERR, "mount failed");
4240 	if (EXT4_SB(sb)->rsv_conversion_wq)
4241 		destroy_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
4242 failed_mount_wq:
4243 	if (sbi->s_journal) {
4244 		jbd2_journal_destroy(sbi->s_journal);
4245 		sbi->s_journal = NULL;
4246 	}
4247 failed_mount3a:
4248 	ext4_es_unregister_shrinker(sbi);
4249 failed_mount3:
4250 	del_timer_sync(&sbi->s_err_report);
4251 	if (sbi->s_mmp_tsk)
4252 		kthread_stop(sbi->s_mmp_tsk);
4253 failed_mount2:
4254 	for (i = 0; i < db_count; i++)
4255 		brelse(sbi->s_group_desc[i]);
4256 	ext4_kvfree(sbi->s_group_desc);
4257 failed_mount:
4258 	if (sbi->s_chksum_driver)
4259 		crypto_free_shash(sbi->s_chksum_driver);
4260 	if (sbi->s_proc) {
4261 		remove_proc_entry("options", sbi->s_proc);
4262 		remove_proc_entry(sb->s_id, ext4_proc_root);
4263 	}
4264 #ifdef CONFIG_QUOTA
4265 	for (i = 0; i < EXT4_MAXQUOTAS; i++)
4266 		kfree(sbi->s_qf_names[i]);
4267 #endif
4268 	ext4_blkdev_remove(sbi);
4269 	brelse(bh);
4270 out_fail:
4271 	sb->s_fs_info = NULL;
4272 	kfree(sbi->s_blockgroup_lock);
4273 	kfree(sbi);
4274 out_free_orig:
4275 	kfree(orig_data);
4276 	return err ? err : ret;
4277 }
4278 
4279 /*
4280  * Setup any per-fs journal parameters now.  We'll do this both on
4281  * initial mount, once the journal has been initialised but before we've
4282  * done any recovery; and again on any subsequent remount.
4283  */
4284 static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
4285 {
4286 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4287 
4288 	journal->j_commit_interval = sbi->s_commit_interval;
4289 	journal->j_min_batch_time = sbi->s_min_batch_time;
4290 	journal->j_max_batch_time = sbi->s_max_batch_time;
4291 
4292 	write_lock(&journal->j_state_lock);
4293 	if (test_opt(sb, BARRIER))
4294 		journal->j_flags |= JBD2_BARRIER;
4295 	else
4296 		journal->j_flags &= ~JBD2_BARRIER;
4297 	if (test_opt(sb, DATA_ERR_ABORT))
4298 		journal->j_flags |= JBD2_ABORT_ON_SYNCDATA_ERR;
4299 	else
4300 		journal->j_flags &= ~JBD2_ABORT_ON_SYNCDATA_ERR;
4301 	write_unlock(&journal->j_state_lock);
4302 }
4303 
4304 static journal_t *ext4_get_journal(struct super_block *sb,
4305 				   unsigned int journal_inum)
4306 {
4307 	struct inode *journal_inode;
4308 	journal_t *journal;
4309 
4310 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4311 
4312 	/* First, test for the existence of a valid inode on disk.  Bad
4313 	 * things happen if we iget() an unused inode, as the subsequent
4314 	 * iput() will try to delete it. */
4315 
4316 	journal_inode = ext4_iget(sb, journal_inum);
4317 	if (IS_ERR(journal_inode)) {
4318 		ext4_msg(sb, KERN_ERR, "no journal found");
4319 		return NULL;
4320 	}
4321 	if (!journal_inode->i_nlink) {
4322 		make_bad_inode(journal_inode);
4323 		iput(journal_inode);
4324 		ext4_msg(sb, KERN_ERR, "journal inode is deleted");
4325 		return NULL;
4326 	}
4327 
4328 	jbd_debug(2, "Journal inode found at %p: %lld bytes\n",
4329 		  journal_inode, journal_inode->i_size);
4330 	if (!S_ISREG(journal_inode->i_mode)) {
4331 		ext4_msg(sb, KERN_ERR, "invalid journal inode");
4332 		iput(journal_inode);
4333 		return NULL;
4334 	}
4335 
4336 	journal = jbd2_journal_init_inode(journal_inode);
4337 	if (!journal) {
4338 		ext4_msg(sb, KERN_ERR, "Could not load journal inode");
4339 		iput(journal_inode);
4340 		return NULL;
4341 	}
4342 	journal->j_private = sb;
4343 	ext4_init_journal_params(sb, journal);
4344 	return journal;
4345 }
4346 
4347 static journal_t *ext4_get_dev_journal(struct super_block *sb,
4348 				       dev_t j_dev)
4349 {
4350 	struct buffer_head *bh;
4351 	journal_t *journal;
4352 	ext4_fsblk_t start;
4353 	ext4_fsblk_t len;
4354 	int hblock, blocksize;
4355 	ext4_fsblk_t sb_block;
4356 	unsigned long offset;
4357 	struct ext4_super_block *es;
4358 	struct block_device *bdev;
4359 
4360 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4361 
4362 	bdev = ext4_blkdev_get(j_dev, sb);
4363 	if (bdev == NULL)
4364 		return NULL;
4365 
4366 	blocksize = sb->s_blocksize;
4367 	hblock = bdev_logical_block_size(bdev);
4368 	if (blocksize < hblock) {
4369 		ext4_msg(sb, KERN_ERR,
4370 			"blocksize too small for journal device");
4371 		goto out_bdev;
4372 	}
4373 
4374 	sb_block = EXT4_MIN_BLOCK_SIZE / blocksize;
4375 	offset = EXT4_MIN_BLOCK_SIZE % blocksize;
4376 	set_blocksize(bdev, blocksize);
4377 	if (!(bh = __bread(bdev, sb_block, blocksize))) {
4378 		ext4_msg(sb, KERN_ERR, "couldn't read superblock of "
4379 		       "external journal");
4380 		goto out_bdev;
4381 	}
4382 
4383 	es = (struct ext4_super_block *) (bh->b_data + offset);
4384 	if ((le16_to_cpu(es->s_magic) != EXT4_SUPER_MAGIC) ||
4385 	    !(le32_to_cpu(es->s_feature_incompat) &
4386 	      EXT4_FEATURE_INCOMPAT_JOURNAL_DEV)) {
4387 		ext4_msg(sb, KERN_ERR, "external journal has "
4388 					"bad superblock");
4389 		brelse(bh);
4390 		goto out_bdev;
4391 	}
4392 
4393 	if ((le32_to_cpu(es->s_feature_ro_compat) &
4394 	     EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
4395 	    es->s_checksum != ext4_superblock_csum(sb, es)) {
4396 		ext4_msg(sb, KERN_ERR, "external journal has "
4397 				       "corrupt superblock");
4398 		brelse(bh);
4399 		goto out_bdev;
4400 	}
4401 
4402 	if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
4403 		ext4_msg(sb, KERN_ERR, "journal UUID does not match");
4404 		brelse(bh);
4405 		goto out_bdev;
4406 	}
4407 
4408 	len = ext4_blocks_count(es);
4409 	start = sb_block + 1;
4410 	brelse(bh);	/* we're done with the superblock */
4411 
4412 	journal = jbd2_journal_init_dev(bdev, sb->s_bdev,
4413 					start, len, blocksize);
4414 	if (!journal) {
4415 		ext4_msg(sb, KERN_ERR, "failed to create device journal");
4416 		goto out_bdev;
4417 	}
4418 	journal->j_private = sb;
4419 	ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &journal->j_sb_buffer);
4420 	wait_on_buffer(journal->j_sb_buffer);
4421 	if (!buffer_uptodate(journal->j_sb_buffer)) {
4422 		ext4_msg(sb, KERN_ERR, "I/O error on journal device");
4423 		goto out_journal;
4424 	}
4425 	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
4426 		ext4_msg(sb, KERN_ERR, "External journal has more than one "
4427 					"user (unsupported) - %d",
4428 			be32_to_cpu(journal->j_superblock->s_nr_users));
4429 		goto out_journal;
4430 	}
4431 	EXT4_SB(sb)->journal_bdev = bdev;
4432 	ext4_init_journal_params(sb, journal);
4433 	return journal;
4434 
4435 out_journal:
4436 	jbd2_journal_destroy(journal);
4437 out_bdev:
4438 	ext4_blkdev_put(bdev);
4439 	return NULL;
4440 }
4441 
4442 static int ext4_load_journal(struct super_block *sb,
4443 			     struct ext4_super_block *es,
4444 			     unsigned long journal_devnum)
4445 {
4446 	journal_t *journal;
4447 	unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
4448 	dev_t journal_dev;
4449 	int err = 0;
4450 	int really_read_only;
4451 
4452 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4453 
4454 	if (journal_devnum &&
4455 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
4456 		ext4_msg(sb, KERN_INFO, "external journal device major/minor "
4457 			"numbers have changed");
4458 		journal_dev = new_decode_dev(journal_devnum);
4459 	} else
4460 		journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));
4461 
4462 	really_read_only = bdev_read_only(sb->s_bdev);
4463 
4464 	/*
4465 	 * Are we loading a blank journal or performing recovery after a
4466 	 * crash?  For recovery, we need to check in advance whether we
4467 	 * can get read-write access to the device.
4468 	 */
4469 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
4470 		if (sb->s_flags & MS_RDONLY) {
4471 			ext4_msg(sb, KERN_INFO, "INFO: recovery "
4472 					"required on readonly filesystem");
4473 			if (really_read_only) {
4474 				ext4_msg(sb, KERN_ERR, "write access "
4475 					"unavailable, cannot proceed");
4476 				return -EROFS;
4477 			}
4478 			ext4_msg(sb, KERN_INFO, "write access will "
4479 			       "be enabled during recovery");
4480 		}
4481 	}
4482 
4483 	if (journal_inum && journal_dev) {
4484 		ext4_msg(sb, KERN_ERR, "filesystem has both journal "
4485 		       "and inode journals!");
4486 		return -EINVAL;
4487 	}
4488 
4489 	if (journal_inum) {
4490 		if (!(journal = ext4_get_journal(sb, journal_inum)))
4491 			return -EINVAL;
4492 	} else {
4493 		if (!(journal = ext4_get_dev_journal(sb, journal_dev)))
4494 			return -EINVAL;
4495 	}
4496 
4497 	if (!(journal->j_flags & JBD2_BARRIER))
4498 		ext4_msg(sb, KERN_INFO, "barriers disabled");
4499 
4500 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER))
4501 		err = jbd2_journal_wipe(journal, !really_read_only);
4502 	if (!err) {
4503 		char *save = kmalloc(EXT4_S_ERR_LEN, GFP_KERNEL);
4504 		if (save)
4505 			memcpy(save, ((char *) es) +
4506 			       EXT4_S_ERR_START, EXT4_S_ERR_LEN);
4507 		err = jbd2_journal_load(journal);
4508 		if (save)
4509 			memcpy(((char *) es) + EXT4_S_ERR_START,
4510 			       save, EXT4_S_ERR_LEN);
4511 		kfree(save);
4512 	}
4513 
4514 	if (err) {
4515 		ext4_msg(sb, KERN_ERR, "error loading journal");
4516 		jbd2_journal_destroy(journal);
4517 		return err;
4518 	}
4519 
4520 	EXT4_SB(sb)->s_journal = journal;
4521 	ext4_clear_journal_err(sb, es);
4522 
4523 	if (!really_read_only && journal_devnum &&
4524 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
4525 		es->s_journal_dev = cpu_to_le32(journal_devnum);
4526 
4527 		/* Make sure we flush the recovery flag to disk. */
4528 		ext4_commit_super(sb, 1);
4529 	}
4530 
4531 	return 0;
4532 }
4533 
4534 static int ext4_commit_super(struct super_block *sb, int sync)
4535 {
4536 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
4537 	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
4538 	int error = 0;
4539 
4540 	if (!sbh || block_device_ejected(sb))
4541 		return error;
4542 	if (buffer_write_io_error(sbh)) {
4543 		/*
4544 		 * Oh, dear.  A previous attempt to write the
4545 		 * superblock failed.  This could happen because the
4546 		 * USB device was yanked out.  Or it could happen to
4547 		 * be a transient write error and maybe the block will
4548 		 * be remapped.  Nothing we can do but to retry the
4549 		 * write and hope for the best.
4550 		 */
4551 		ext4_msg(sb, KERN_ERR, "previous I/O error to "
4552 		       "superblock detected");
4553 		clear_buffer_write_io_error(sbh);
4554 		set_buffer_uptodate(sbh);
4555 	}
4556 	/*
4557 	 * If the file system is mounted read-only, don't update the
4558 	 * superblock write time.  This avoids updating the superblock
4559 	 * write time when we are mounting the root file system
4560 	 * read/only but we need to replay the journal; at that point,
4561 	 * for people who are east of GMT and who make their clock
4562 	 * tick in localtime for Windows bug-for-bug compatibility,
4563 	 * the clock is set in the future, and this will cause e2fsck
4564 	 * to complain and force a full file system check.
4565 	 */
4566 	if (!(sb->s_flags & MS_RDONLY))
4567 		es->s_wtime = cpu_to_le32(get_seconds());
4568 	if (sb->s_bdev->bd_part)
4569 		es->s_kbytes_written =
4570 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written +
4571 			    ((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
4572 			      EXT4_SB(sb)->s_sectors_written_start) >> 1));
4573 	else
4574 		es->s_kbytes_written =
4575 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written);
4576 	if (percpu_counter_initialized(&EXT4_SB(sb)->s_freeclusters_counter))
4577 		ext4_free_blocks_count_set(es,
4578 			EXT4_C2B(EXT4_SB(sb), percpu_counter_sum_positive(
4579 				&EXT4_SB(sb)->s_freeclusters_counter)));
4580 	if (percpu_counter_initialized(&EXT4_SB(sb)->s_freeinodes_counter))
4581 		es->s_free_inodes_count =
4582 			cpu_to_le32(percpu_counter_sum_positive(
4583 				&EXT4_SB(sb)->s_freeinodes_counter));
4584 	BUFFER_TRACE(sbh, "marking dirty");
4585 	ext4_superblock_csum_set(sb);
4586 	mark_buffer_dirty(sbh);
4587 	if (sync) {
4588 		error = sync_dirty_buffer(sbh);
4589 		if (error)
4590 			return error;
4591 
4592 		error = buffer_write_io_error(sbh);
4593 		if (error) {
4594 			ext4_msg(sb, KERN_ERR, "I/O error while writing "
4595 			       "superblock");
4596 			clear_buffer_write_io_error(sbh);
4597 			set_buffer_uptodate(sbh);
4598 		}
4599 	}
4600 	return error;
4601 }
4602 
4603 /*
4604  * Have we just finished recovery?  If so, and if we are mounting (or
4605  * remounting) the filesystem readonly, then we will end up with a
4606  * consistent fs on disk.  Record that fact.
4607  */
4608 static void ext4_mark_recovery_complete(struct super_block *sb,
4609 					struct ext4_super_block *es)
4610 {
4611 	journal_t *journal = EXT4_SB(sb)->s_journal;
4612 
4613 	if (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
4614 		BUG_ON(journal != NULL);
4615 		return;
4616 	}
4617 	jbd2_journal_lock_updates(journal);
4618 	if (jbd2_journal_flush(journal) < 0)
4619 		goto out;
4620 
4621 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER) &&
4622 	    sb->s_flags & MS_RDONLY) {
4623 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4624 		ext4_commit_super(sb, 1);
4625 	}
4626 
4627 out:
4628 	jbd2_journal_unlock_updates(journal);
4629 }
4630 
4631 /*
4632  * If we are mounting (or read-write remounting) a filesystem whose journal
4633  * has recorded an error from a previous lifetime, move that error to the
4634  * main filesystem now.
4635  */
4636 static void ext4_clear_journal_err(struct super_block *sb,
4637 				   struct ext4_super_block *es)
4638 {
4639 	journal_t *journal;
4640 	int j_errno;
4641 	const char *errstr;
4642 
4643 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4644 
4645 	journal = EXT4_SB(sb)->s_journal;
4646 
4647 	/*
4648 	 * Now check for any error status which may have been recorded in the
4649 	 * journal by a prior ext4_error() or ext4_abort()
4650 	 */
4651 
4652 	j_errno = jbd2_journal_errno(journal);
4653 	if (j_errno) {
4654 		char nbuf[16];
4655 
4656 		errstr = ext4_decode_error(sb, j_errno, nbuf);
4657 		ext4_warning(sb, "Filesystem error recorded "
4658 			     "from previous mount: %s", errstr);
4659 		ext4_warning(sb, "Marking fs in need of filesystem check.");
4660 
4661 		EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
4662 		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
4663 		ext4_commit_super(sb, 1);
4664 
4665 		jbd2_journal_clear_err(journal);
4666 		jbd2_journal_update_sb_errno(journal);
4667 	}
4668 }
4669 
4670 /*
4671  * Force the running and committing transactions to commit,
4672  * and wait on the commit.
4673  */
4674 int ext4_force_commit(struct super_block *sb)
4675 {
4676 	journal_t *journal;
4677 
4678 	if (sb->s_flags & MS_RDONLY)
4679 		return 0;
4680 
4681 	journal = EXT4_SB(sb)->s_journal;
4682 	return ext4_journal_force_commit(journal);
4683 }
4684 
4685 static int ext4_sync_fs(struct super_block *sb, int wait)
4686 {
4687 	int ret = 0;
4688 	tid_t target;
4689 	bool needs_barrier = false;
4690 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4691 
4692 	trace_ext4_sync_fs(sb, wait);
4693 	flush_workqueue(sbi->rsv_conversion_wq);
4694 	/*
4695 	 * Writeback quota in non-journalled quota case - journalled quota has
4696 	 * no dirty dquots
4697 	 */
4698 	dquot_writeback_dquots(sb, -1);
4699 	/*
4700 	 * Data writeback is possible w/o journal transaction, so barrier must
4701 	 * being sent at the end of the function. But we can skip it if
4702 	 * transaction_commit will do it for us.
4703 	 */
4704 	if (sbi->s_journal) {
4705 		target = jbd2_get_latest_transaction(sbi->s_journal);
4706 		if (wait && sbi->s_journal->j_flags & JBD2_BARRIER &&
4707 		    !jbd2_trans_will_send_data_barrier(sbi->s_journal, target))
4708 			needs_barrier = true;
4709 
4710 		if (jbd2_journal_start_commit(sbi->s_journal, &target)) {
4711 			if (wait)
4712 				ret = jbd2_log_wait_commit(sbi->s_journal,
4713 							   target);
4714 		}
4715 	} else if (wait && test_opt(sb, BARRIER))
4716 		needs_barrier = true;
4717 	if (needs_barrier) {
4718 		int err;
4719 		err = blkdev_issue_flush(sb->s_bdev, GFP_KERNEL, NULL);
4720 		if (!ret)
4721 			ret = err;
4722 	}
4723 
4724 	return ret;
4725 }
4726 
4727 /*
4728  * LVM calls this function before a (read-only) snapshot is created.  This
4729  * gives us a chance to flush the journal completely and mark the fs clean.
4730  *
4731  * Note that only this function cannot bring a filesystem to be in a clean
4732  * state independently. It relies on upper layer to stop all data & metadata
4733  * modifications.
4734  */
4735 static int ext4_freeze(struct super_block *sb)
4736 {
4737 	int error = 0;
4738 	journal_t *journal;
4739 
4740 	if (sb->s_flags & MS_RDONLY)
4741 		return 0;
4742 
4743 	journal = EXT4_SB(sb)->s_journal;
4744 
4745 	if (journal) {
4746 		/* Now we set up the journal barrier. */
4747 		jbd2_journal_lock_updates(journal);
4748 
4749 		/*
4750 		 * Don't clear the needs_recovery flag if we failed to
4751 		 * flush the journal.
4752 		 */
4753 		error = jbd2_journal_flush(journal);
4754 		if (error < 0)
4755 			goto out;
4756 	}
4757 
4758 	/* Journal blocked and flushed, clear needs_recovery flag. */
4759 	EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4760 	error = ext4_commit_super(sb, 1);
4761 out:
4762 	if (journal)
4763 		/* we rely on upper layer to stop further updates */
4764 		jbd2_journal_unlock_updates(journal);
4765 	return error;
4766 }
4767 
4768 /*
4769  * Called by LVM after the snapshot is done.  We need to reset the RECOVER
4770  * flag here, even though the filesystem is not technically dirty yet.
4771  */
4772 static int ext4_unfreeze(struct super_block *sb)
4773 {
4774 	if (sb->s_flags & MS_RDONLY)
4775 		return 0;
4776 
4777 	/* Reset the needs_recovery flag before the fs is unlocked. */
4778 	EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4779 	ext4_commit_super(sb, 1);
4780 	return 0;
4781 }
4782 
4783 /*
4784  * Structure to save mount options for ext4_remount's benefit
4785  */
4786 struct ext4_mount_options {
4787 	unsigned long s_mount_opt;
4788 	unsigned long s_mount_opt2;
4789 	kuid_t s_resuid;
4790 	kgid_t s_resgid;
4791 	unsigned long s_commit_interval;
4792 	u32 s_min_batch_time, s_max_batch_time;
4793 #ifdef CONFIG_QUOTA
4794 	int s_jquota_fmt;
4795 	char *s_qf_names[EXT4_MAXQUOTAS];
4796 #endif
4797 };
4798 
4799 static int ext4_remount(struct super_block *sb, int *flags, char *data)
4800 {
4801 	struct ext4_super_block *es;
4802 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4803 	unsigned long old_sb_flags;
4804 	struct ext4_mount_options old_opts;
4805 	int enable_quota = 0;
4806 	ext4_group_t g;
4807 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
4808 	int err = 0;
4809 #ifdef CONFIG_QUOTA
4810 	int i, j;
4811 #endif
4812 	char *orig_data = kstrdup(data, GFP_KERNEL);
4813 
4814 	/* Store the original options */
4815 	old_sb_flags = sb->s_flags;
4816 	old_opts.s_mount_opt = sbi->s_mount_opt;
4817 	old_opts.s_mount_opt2 = sbi->s_mount_opt2;
4818 	old_opts.s_resuid = sbi->s_resuid;
4819 	old_opts.s_resgid = sbi->s_resgid;
4820 	old_opts.s_commit_interval = sbi->s_commit_interval;
4821 	old_opts.s_min_batch_time = sbi->s_min_batch_time;
4822 	old_opts.s_max_batch_time = sbi->s_max_batch_time;
4823 #ifdef CONFIG_QUOTA
4824 	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
4825 	for (i = 0; i < EXT4_MAXQUOTAS; i++)
4826 		if (sbi->s_qf_names[i]) {
4827 			old_opts.s_qf_names[i] = kstrdup(sbi->s_qf_names[i],
4828 							 GFP_KERNEL);
4829 			if (!old_opts.s_qf_names[i]) {
4830 				for (j = 0; j < i; j++)
4831 					kfree(old_opts.s_qf_names[j]);
4832 				kfree(orig_data);
4833 				return -ENOMEM;
4834 			}
4835 		} else
4836 			old_opts.s_qf_names[i] = NULL;
4837 #endif
4838 	if (sbi->s_journal && sbi->s_journal->j_task->io_context)
4839 		journal_ioprio = sbi->s_journal->j_task->io_context->ioprio;
4840 
4841 	/*
4842 	 * Allow the "check" option to be passed as a remount option.
4843 	 */
4844 	if (!parse_options(data, sb, NULL, &journal_ioprio, 1)) {
4845 		err = -EINVAL;
4846 		goto restore_opts;
4847 	}
4848 
4849 	if ((old_opts.s_mount_opt & EXT4_MOUNT_JOURNAL_CHECKSUM) ^
4850 	    test_opt(sb, JOURNAL_CHECKSUM)) {
4851 		ext4_msg(sb, KERN_ERR, "changing journal_checksum "
4852 			 "during remount not supported");
4853 		err = -EINVAL;
4854 		goto restore_opts;
4855 	}
4856 
4857 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
4858 		if (test_opt2(sb, EXPLICIT_DELALLOC)) {
4859 			ext4_msg(sb, KERN_ERR, "can't mount with "
4860 				 "both data=journal and delalloc");
4861 			err = -EINVAL;
4862 			goto restore_opts;
4863 		}
4864 		if (test_opt(sb, DIOREAD_NOLOCK)) {
4865 			ext4_msg(sb, KERN_ERR, "can't mount with "
4866 				 "both data=journal and dioread_nolock");
4867 			err = -EINVAL;
4868 			goto restore_opts;
4869 		}
4870 	}
4871 
4872 	if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
4873 		ext4_abort(sb, "Abort forced by user");
4874 
4875 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
4876 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
4877 
4878 	es = sbi->s_es;
4879 
4880 	if (sbi->s_journal) {
4881 		ext4_init_journal_params(sb, sbi->s_journal);
4882 		set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
4883 	}
4884 
4885 	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY)) {
4886 		if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) {
4887 			err = -EROFS;
4888 			goto restore_opts;
4889 		}
4890 
4891 		if (*flags & MS_RDONLY) {
4892 			err = sync_filesystem(sb);
4893 			if (err < 0)
4894 				goto restore_opts;
4895 			err = dquot_suspend(sb, -1);
4896 			if (err < 0)
4897 				goto restore_opts;
4898 
4899 			/*
4900 			 * First of all, the unconditional stuff we have to do
4901 			 * to disable replay of the journal when we next remount
4902 			 */
4903 			sb->s_flags |= MS_RDONLY;
4904 
4905 			/*
4906 			 * OK, test if we are remounting a valid rw partition
4907 			 * readonly, and if so set the rdonly flag and then
4908 			 * mark the partition as valid again.
4909 			 */
4910 			if (!(es->s_state & cpu_to_le16(EXT4_VALID_FS)) &&
4911 			    (sbi->s_mount_state & EXT4_VALID_FS))
4912 				es->s_state = cpu_to_le16(sbi->s_mount_state);
4913 
4914 			if (sbi->s_journal)
4915 				ext4_mark_recovery_complete(sb, es);
4916 		} else {
4917 			/* Make sure we can mount this feature set readwrite */
4918 			if (!ext4_feature_set_ok(sb, 0)) {
4919 				err = -EROFS;
4920 				goto restore_opts;
4921 			}
4922 			/*
4923 			 * Make sure the group descriptor checksums
4924 			 * are sane.  If they aren't, refuse to remount r/w.
4925 			 */
4926 			for (g = 0; g < sbi->s_groups_count; g++) {
4927 				struct ext4_group_desc *gdp =
4928 					ext4_get_group_desc(sb, g, NULL);
4929 
4930 				if (!ext4_group_desc_csum_verify(sb, g, gdp)) {
4931 					ext4_msg(sb, KERN_ERR,
4932 	       "ext4_remount: Checksum for group %u failed (%u!=%u)",
4933 		g, le16_to_cpu(ext4_group_desc_csum(sbi, g, gdp)),
4934 					       le16_to_cpu(gdp->bg_checksum));
4935 					err = -EINVAL;
4936 					goto restore_opts;
4937 				}
4938 			}
4939 
4940 			/*
4941 			 * If we have an unprocessed orphan list hanging
4942 			 * around from a previously readonly bdev mount,
4943 			 * require a full umount/remount for now.
4944 			 */
4945 			if (es->s_last_orphan) {
4946 				ext4_msg(sb, KERN_WARNING, "Couldn't "
4947 				       "remount RDWR because of unprocessed "
4948 				       "orphan inode list.  Please "
4949 				       "umount/remount instead");
4950 				err = -EINVAL;
4951 				goto restore_opts;
4952 			}
4953 
4954 			/*
4955 			 * Mounting a RDONLY partition read-write, so reread
4956 			 * and store the current valid flag.  (It may have
4957 			 * been changed by e2fsck since we originally mounted
4958 			 * the partition.)
4959 			 */
4960 			if (sbi->s_journal)
4961 				ext4_clear_journal_err(sb, es);
4962 			sbi->s_mount_state = le16_to_cpu(es->s_state);
4963 			if (!ext4_setup_super(sb, es, 0))
4964 				sb->s_flags &= ~MS_RDONLY;
4965 			if (EXT4_HAS_INCOMPAT_FEATURE(sb,
4966 						     EXT4_FEATURE_INCOMPAT_MMP))
4967 				if (ext4_multi_mount_protect(sb,
4968 						le64_to_cpu(es->s_mmp_block))) {
4969 					err = -EROFS;
4970 					goto restore_opts;
4971 				}
4972 			enable_quota = 1;
4973 		}
4974 	}
4975 
4976 	/*
4977 	 * Reinitialize lazy itable initialization thread based on
4978 	 * current settings
4979 	 */
4980 	if ((sb->s_flags & MS_RDONLY) || !test_opt(sb, INIT_INODE_TABLE))
4981 		ext4_unregister_li_request(sb);
4982 	else {
4983 		ext4_group_t first_not_zeroed;
4984 		first_not_zeroed = ext4_has_uninit_itable(sb);
4985 		ext4_register_li_request(sb, first_not_zeroed);
4986 	}
4987 
4988 	ext4_setup_system_zone(sb);
4989 	if (sbi->s_journal == NULL && !(old_sb_flags & MS_RDONLY))
4990 		ext4_commit_super(sb, 1);
4991 
4992 #ifdef CONFIG_QUOTA
4993 	/* Release old quota file names */
4994 	for (i = 0; i < EXT4_MAXQUOTAS; i++)
4995 		kfree(old_opts.s_qf_names[i]);
4996 	if (enable_quota) {
4997 		if (sb_any_quota_suspended(sb))
4998 			dquot_resume(sb, -1);
4999 		else if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
5000 					EXT4_FEATURE_RO_COMPAT_QUOTA)) {
5001 			err = ext4_enable_quotas(sb);
5002 			if (err)
5003 				goto restore_opts;
5004 		}
5005 	}
5006 #endif
5007 
5008 	ext4_msg(sb, KERN_INFO, "re-mounted. Opts: %s", orig_data);
5009 	kfree(orig_data);
5010 	return 0;
5011 
5012 restore_opts:
5013 	sb->s_flags = old_sb_flags;
5014 	sbi->s_mount_opt = old_opts.s_mount_opt;
5015 	sbi->s_mount_opt2 = old_opts.s_mount_opt2;
5016 	sbi->s_resuid = old_opts.s_resuid;
5017 	sbi->s_resgid = old_opts.s_resgid;
5018 	sbi->s_commit_interval = old_opts.s_commit_interval;
5019 	sbi->s_min_batch_time = old_opts.s_min_batch_time;
5020 	sbi->s_max_batch_time = old_opts.s_max_batch_time;
5021 #ifdef CONFIG_QUOTA
5022 	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
5023 	for (i = 0; i < EXT4_MAXQUOTAS; i++) {
5024 		kfree(sbi->s_qf_names[i]);
5025 		sbi->s_qf_names[i] = old_opts.s_qf_names[i];
5026 	}
5027 #endif
5028 	kfree(orig_data);
5029 	return err;
5030 }
5031 
5032 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
5033 {
5034 	struct super_block *sb = dentry->d_sb;
5035 	struct ext4_sb_info *sbi = EXT4_SB(sb);
5036 	struct ext4_super_block *es = sbi->s_es;
5037 	ext4_fsblk_t overhead = 0, resv_blocks;
5038 	u64 fsid;
5039 	s64 bfree;
5040 	resv_blocks = EXT4_C2B(sbi, atomic64_read(&sbi->s_resv_clusters));
5041 
5042 	if (!test_opt(sb, MINIX_DF))
5043 		overhead = sbi->s_overhead;
5044 
5045 	buf->f_type = EXT4_SUPER_MAGIC;
5046 	buf->f_bsize = sb->s_blocksize;
5047 	buf->f_blocks = ext4_blocks_count(es) - EXT4_C2B(sbi, overhead);
5048 	bfree = percpu_counter_sum_positive(&sbi->s_freeclusters_counter) -
5049 		percpu_counter_sum_positive(&sbi->s_dirtyclusters_counter);
5050 	/* prevent underflow in case that few free space is available */
5051 	buf->f_bfree = EXT4_C2B(sbi, max_t(s64, bfree, 0));
5052 	buf->f_bavail = buf->f_bfree -
5053 			(ext4_r_blocks_count(es) + resv_blocks);
5054 	if (buf->f_bfree < (ext4_r_blocks_count(es) + resv_blocks))
5055 		buf->f_bavail = 0;
5056 	buf->f_files = le32_to_cpu(es->s_inodes_count);
5057 	buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter);
5058 	buf->f_namelen = EXT4_NAME_LEN;
5059 	fsid = le64_to_cpup((void *)es->s_uuid) ^
5060 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
5061 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
5062 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
5063 
5064 	return 0;
5065 }
5066 
5067 /* Helper function for writing quotas on sync - we need to start transaction
5068  * before quota file is locked for write. Otherwise the are possible deadlocks:
5069  * Process 1                         Process 2
5070  * ext4_create()                     quota_sync()
5071  *   jbd2_journal_start()                  write_dquot()
5072  *   dquot_initialize()                         down(dqio_mutex)
5073  *     down(dqio_mutex)                    jbd2_journal_start()
5074  *
5075  */
5076 
5077 #ifdef CONFIG_QUOTA
5078 
5079 static inline struct inode *dquot_to_inode(struct dquot *dquot)
5080 {
5081 	return sb_dqopt(dquot->dq_sb)->files[dquot->dq_id.type];
5082 }
5083 
5084 static int ext4_write_dquot(struct dquot *dquot)
5085 {
5086 	int ret, err;
5087 	handle_t *handle;
5088 	struct inode *inode;
5089 
5090 	inode = dquot_to_inode(dquot);
5091 	handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
5092 				    EXT4_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
5093 	if (IS_ERR(handle))
5094 		return PTR_ERR(handle);
5095 	ret = dquot_commit(dquot);
5096 	err = ext4_journal_stop(handle);
5097 	if (!ret)
5098 		ret = err;
5099 	return ret;
5100 }
5101 
5102 static int ext4_acquire_dquot(struct dquot *dquot)
5103 {
5104 	int ret, err;
5105 	handle_t *handle;
5106 
5107 	handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
5108 				    EXT4_QUOTA_INIT_BLOCKS(dquot->dq_sb));
5109 	if (IS_ERR(handle))
5110 		return PTR_ERR(handle);
5111 	ret = dquot_acquire(dquot);
5112 	err = ext4_journal_stop(handle);
5113 	if (!ret)
5114 		ret = err;
5115 	return ret;
5116 }
5117 
5118 static int ext4_release_dquot(struct dquot *dquot)
5119 {
5120 	int ret, err;
5121 	handle_t *handle;
5122 
5123 	handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
5124 				    EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
5125 	if (IS_ERR(handle)) {
5126 		/* Release dquot anyway to avoid endless cycle in dqput() */
5127 		dquot_release(dquot);
5128 		return PTR_ERR(handle);
5129 	}
5130 	ret = dquot_release(dquot);
5131 	err = ext4_journal_stop(handle);
5132 	if (!ret)
5133 		ret = err;
5134 	return ret;
5135 }
5136 
5137 static int ext4_mark_dquot_dirty(struct dquot *dquot)
5138 {
5139 	struct super_block *sb = dquot->dq_sb;
5140 	struct ext4_sb_info *sbi = EXT4_SB(sb);
5141 
5142 	/* Are we journaling quotas? */
5143 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA) ||
5144 	    sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
5145 		dquot_mark_dquot_dirty(dquot);
5146 		return ext4_write_dquot(dquot);
5147 	} else {
5148 		return dquot_mark_dquot_dirty(dquot);
5149 	}
5150 }
5151 
5152 static int ext4_write_info(struct super_block *sb, int type)
5153 {
5154 	int ret, err;
5155 	handle_t *handle;
5156 
5157 	/* Data block + inode block */
5158 	handle = ext4_journal_start(sb->s_root->d_inode, EXT4_HT_QUOTA, 2);
5159 	if (IS_ERR(handle))
5160 		return PTR_ERR(handle);
5161 	ret = dquot_commit_info(sb, type);
5162 	err = ext4_journal_stop(handle);
5163 	if (!ret)
5164 		ret = err;
5165 	return ret;
5166 }
5167 
5168 /*
5169  * Turn on quotas during mount time - we need to find
5170  * the quota file and such...
5171  */
5172 static int ext4_quota_on_mount(struct super_block *sb, int type)
5173 {
5174 	return dquot_quota_on_mount(sb, EXT4_SB(sb)->s_qf_names[type],
5175 					EXT4_SB(sb)->s_jquota_fmt, type);
5176 }
5177 
5178 /*
5179  * Standard function to be called on quota_on
5180  */
5181 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
5182 			 struct path *path)
5183 {
5184 	int err;
5185 
5186 	if (!test_opt(sb, QUOTA))
5187 		return -EINVAL;
5188 
5189 	/* Quotafile not on the same filesystem? */
5190 	if (path->dentry->d_sb != sb)
5191 		return -EXDEV;
5192 	/* Journaling quota? */
5193 	if (EXT4_SB(sb)->s_qf_names[type]) {
5194 		/* Quotafile not in fs root? */
5195 		if (path->dentry->d_parent != sb->s_root)
5196 			ext4_msg(sb, KERN_WARNING,
5197 				"Quota file not on filesystem root. "
5198 				"Journaled quota will not work");
5199 	}
5200 
5201 	/*
5202 	 * When we journal data on quota file, we have to flush journal to see
5203 	 * all updates to the file when we bypass pagecache...
5204 	 */
5205 	if (EXT4_SB(sb)->s_journal &&
5206 	    ext4_should_journal_data(path->dentry->d_inode)) {
5207 		/*
5208 		 * We don't need to lock updates but journal_flush() could
5209 		 * otherwise be livelocked...
5210 		 */
5211 		jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
5212 		err = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
5213 		jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
5214 		if (err)
5215 			return err;
5216 	}
5217 
5218 	return dquot_quota_on(sb, type, format_id, path);
5219 }
5220 
5221 static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
5222 			     unsigned int flags)
5223 {
5224 	int err;
5225 	struct inode *qf_inode;
5226 	unsigned long qf_inums[EXT4_MAXQUOTAS] = {
5227 		le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
5228 		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum)
5229 	};
5230 
5231 	BUG_ON(!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA));
5232 
5233 	if (!qf_inums[type])
5234 		return -EPERM;
5235 
5236 	qf_inode = ext4_iget(sb, qf_inums[type]);
5237 	if (IS_ERR(qf_inode)) {
5238 		ext4_error(sb, "Bad quota inode # %lu", qf_inums[type]);
5239 		return PTR_ERR(qf_inode);
5240 	}
5241 
5242 	/* Don't account quota for quota files to avoid recursion */
5243 	qf_inode->i_flags |= S_NOQUOTA;
5244 	err = dquot_enable(qf_inode, type, format_id, flags);
5245 	iput(qf_inode);
5246 
5247 	return err;
5248 }
5249 
5250 /* Enable usage tracking for all quota types. */
5251 static int ext4_enable_quotas(struct super_block *sb)
5252 {
5253 	int type, err = 0;
5254 	unsigned long qf_inums[EXT4_MAXQUOTAS] = {
5255 		le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
5256 		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum)
5257 	};
5258 
5259 	sb_dqopt(sb)->flags |= DQUOT_QUOTA_SYS_FILE;
5260 	for (type = 0; type < EXT4_MAXQUOTAS; type++) {
5261 		if (qf_inums[type]) {
5262 			err = ext4_quota_enable(sb, type, QFMT_VFS_V1,
5263 						DQUOT_USAGE_ENABLED);
5264 			if (err) {
5265 				ext4_warning(sb,
5266 					"Failed to enable quota tracking "
5267 					"(type=%d, err=%d). Please run "
5268 					"e2fsck to fix.", type, err);
5269 				return err;
5270 			}
5271 		}
5272 	}
5273 	return 0;
5274 }
5275 
5276 /*
5277  * quota_on function that is used when QUOTA feature is set.
5278  */
5279 static int ext4_quota_on_sysfile(struct super_block *sb, int type,
5280 				 int format_id)
5281 {
5282 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA))
5283 		return -EINVAL;
5284 
5285 	/*
5286 	 * USAGE was enabled at mount time. Only need to enable LIMITS now.
5287 	 */
5288 	return ext4_quota_enable(sb, type, format_id, DQUOT_LIMITS_ENABLED);
5289 }
5290 
5291 static int ext4_quota_off(struct super_block *sb, int type)
5292 {
5293 	struct inode *inode = sb_dqopt(sb)->files[type];
5294 	handle_t *handle;
5295 
5296 	/* Force all delayed allocation blocks to be allocated.
5297 	 * Caller already holds s_umount sem */
5298 	if (test_opt(sb, DELALLOC))
5299 		sync_filesystem(sb);
5300 
5301 	if (!inode)
5302 		goto out;
5303 
5304 	/* Update modification times of quota files when userspace can
5305 	 * start looking at them */
5306 	handle = ext4_journal_start(inode, EXT4_HT_QUOTA, 1);
5307 	if (IS_ERR(handle))
5308 		goto out;
5309 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
5310 	ext4_mark_inode_dirty(handle, inode);
5311 	ext4_journal_stop(handle);
5312 
5313 out:
5314 	return dquot_quota_off(sb, type);
5315 }
5316 
5317 /*
5318  * quota_off function that is used when QUOTA feature is set.
5319  */
5320 static int ext4_quota_off_sysfile(struct super_block *sb, int type)
5321 {
5322 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA))
5323 		return -EINVAL;
5324 
5325 	/* Disable only the limits. */
5326 	return dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
5327 }
5328 
5329 /* Read data from quotafile - avoid pagecache and such because we cannot afford
5330  * acquiring the locks... As quota files are never truncated and quota code
5331  * itself serializes the operations (and no one else should touch the files)
5332  * we don't have to be afraid of races */
5333 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
5334 			       size_t len, loff_t off)
5335 {
5336 	struct inode *inode = sb_dqopt(sb)->files[type];
5337 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
5338 	int offset = off & (sb->s_blocksize - 1);
5339 	int tocopy;
5340 	size_t toread;
5341 	struct buffer_head *bh;
5342 	loff_t i_size = i_size_read(inode);
5343 
5344 	if (off > i_size)
5345 		return 0;
5346 	if (off+len > i_size)
5347 		len = i_size-off;
5348 	toread = len;
5349 	while (toread > 0) {
5350 		tocopy = sb->s_blocksize - offset < toread ?
5351 				sb->s_blocksize - offset : toread;
5352 		bh = ext4_bread(NULL, inode, blk, 0);
5353 		if (IS_ERR(bh))
5354 			return PTR_ERR(bh);
5355 		if (!bh)	/* A hole? */
5356 			memset(data, 0, tocopy);
5357 		else
5358 			memcpy(data, bh->b_data+offset, tocopy);
5359 		brelse(bh);
5360 		offset = 0;
5361 		toread -= tocopy;
5362 		data += tocopy;
5363 		blk++;
5364 	}
5365 	return len;
5366 }
5367 
5368 /* Write to quotafile (we know the transaction is already started and has
5369  * enough credits) */
5370 static ssize_t ext4_quota_write(struct super_block *sb, int type,
5371 				const char *data, size_t len, loff_t off)
5372 {
5373 	struct inode *inode = sb_dqopt(sb)->files[type];
5374 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
5375 	int err, offset = off & (sb->s_blocksize - 1);
5376 	struct buffer_head *bh;
5377 	handle_t *handle = journal_current_handle();
5378 
5379 	if (EXT4_SB(sb)->s_journal && !handle) {
5380 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
5381 			" cancelled because transaction is not started",
5382 			(unsigned long long)off, (unsigned long long)len);
5383 		return -EIO;
5384 	}
5385 	/*
5386 	 * Since we account only one data block in transaction credits,
5387 	 * then it is impossible to cross a block boundary.
5388 	 */
5389 	if (sb->s_blocksize - offset < len) {
5390 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
5391 			" cancelled because not block aligned",
5392 			(unsigned long long)off, (unsigned long long)len);
5393 		return -EIO;
5394 	}
5395 
5396 	bh = ext4_bread(handle, inode, blk, 1);
5397 	if (IS_ERR(bh))
5398 		return PTR_ERR(bh);
5399 	if (!bh)
5400 		goto out;
5401 	BUFFER_TRACE(bh, "get write access");
5402 	err = ext4_journal_get_write_access(handle, bh);
5403 	if (err) {
5404 		brelse(bh);
5405 		return err;
5406 	}
5407 	lock_buffer(bh);
5408 	memcpy(bh->b_data+offset, data, len);
5409 	flush_dcache_page(bh->b_page);
5410 	unlock_buffer(bh);
5411 	err = ext4_handle_dirty_metadata(handle, NULL, bh);
5412 	brelse(bh);
5413 out:
5414 	if (inode->i_size < off + len) {
5415 		i_size_write(inode, off + len);
5416 		EXT4_I(inode)->i_disksize = inode->i_size;
5417 		ext4_mark_inode_dirty(handle, inode);
5418 	}
5419 	return len;
5420 }
5421 
5422 #endif
5423 
5424 static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
5425 		       const char *dev_name, void *data)
5426 {
5427 	return mount_bdev(fs_type, flags, dev_name, data, ext4_fill_super);
5428 }
5429 
5430 #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
5431 static inline void register_as_ext2(void)
5432 {
5433 	int err = register_filesystem(&ext2_fs_type);
5434 	if (err)
5435 		printk(KERN_WARNING
5436 		       "EXT4-fs: Unable to register as ext2 (%d)\n", err);
5437 }
5438 
5439 static inline void unregister_as_ext2(void)
5440 {
5441 	unregister_filesystem(&ext2_fs_type);
5442 }
5443 
5444 static inline int ext2_feature_set_ok(struct super_block *sb)
5445 {
5446 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP))
5447 		return 0;
5448 	if (sb->s_flags & MS_RDONLY)
5449 		return 1;
5450 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))
5451 		return 0;
5452 	return 1;
5453 }
5454 #else
5455 static inline void register_as_ext2(void) { }
5456 static inline void unregister_as_ext2(void) { }
5457 static inline int ext2_feature_set_ok(struct super_block *sb) { return 0; }
5458 #endif
5459 
5460 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
5461 static inline void register_as_ext3(void)
5462 {
5463 	int err = register_filesystem(&ext3_fs_type);
5464 	if (err)
5465 		printk(KERN_WARNING
5466 		       "EXT4-fs: Unable to register as ext3 (%d)\n", err);
5467 }
5468 
5469 static inline void unregister_as_ext3(void)
5470 {
5471 	unregister_filesystem(&ext3_fs_type);
5472 }
5473 
5474 static inline int ext3_feature_set_ok(struct super_block *sb)
5475 {
5476 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT3_FEATURE_INCOMPAT_SUPP))
5477 		return 0;
5478 	if (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL))
5479 		return 0;
5480 	if (sb->s_flags & MS_RDONLY)
5481 		return 1;
5482 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT3_FEATURE_RO_COMPAT_SUPP))
5483 		return 0;
5484 	return 1;
5485 }
5486 #else
5487 static inline void register_as_ext3(void) { }
5488 static inline void unregister_as_ext3(void) { }
5489 static inline int ext3_feature_set_ok(struct super_block *sb) { return 0; }
5490 #endif
5491 
5492 static struct file_system_type ext4_fs_type = {
5493 	.owner		= THIS_MODULE,
5494 	.name		= "ext4",
5495 	.mount		= ext4_mount,
5496 	.kill_sb	= kill_block_super,
5497 	.fs_flags	= FS_REQUIRES_DEV,
5498 };
5499 MODULE_ALIAS_FS("ext4");
5500 
5501 static int __init ext4_init_feat_adverts(void)
5502 {
5503 	struct ext4_features *ef;
5504 	int ret = -ENOMEM;
5505 
5506 	ef = kzalloc(sizeof(struct ext4_features), GFP_KERNEL);
5507 	if (!ef)
5508 		goto out;
5509 
5510 	ef->f_kobj.kset = ext4_kset;
5511 	init_completion(&ef->f_kobj_unregister);
5512 	ret = kobject_init_and_add(&ef->f_kobj, &ext4_feat_ktype, NULL,
5513 				   "features");
5514 	if (ret) {
5515 		kfree(ef);
5516 		goto out;
5517 	}
5518 
5519 	ext4_feat = ef;
5520 	ret = 0;
5521 out:
5522 	return ret;
5523 }
5524 
5525 static void ext4_exit_feat_adverts(void)
5526 {
5527 	kobject_put(&ext4_feat->f_kobj);
5528 	wait_for_completion(&ext4_feat->f_kobj_unregister);
5529 	kfree(ext4_feat);
5530 }
5531 
5532 /* Shared across all ext4 file systems */
5533 wait_queue_head_t ext4__ioend_wq[EXT4_WQ_HASH_SZ];
5534 struct mutex ext4__aio_mutex[EXT4_WQ_HASH_SZ];
5535 
5536 static int __init ext4_init_fs(void)
5537 {
5538 	int i, err;
5539 
5540 	ext4_li_info = NULL;
5541 	mutex_init(&ext4_li_mtx);
5542 
5543 	/* Build-time check for flags consistency */
5544 	ext4_check_flag_values();
5545 
5546 	for (i = 0; i < EXT4_WQ_HASH_SZ; i++) {
5547 		mutex_init(&ext4__aio_mutex[i]);
5548 		init_waitqueue_head(&ext4__ioend_wq[i]);
5549 	}
5550 
5551 	err = ext4_init_es();
5552 	if (err)
5553 		return err;
5554 
5555 	err = ext4_init_pageio();
5556 	if (err)
5557 		goto out7;
5558 
5559 	err = ext4_init_system_zone();
5560 	if (err)
5561 		goto out6;
5562 	ext4_kset = kset_create_and_add("ext4", NULL, fs_kobj);
5563 	if (!ext4_kset) {
5564 		err = -ENOMEM;
5565 		goto out5;
5566 	}
5567 	ext4_proc_root = proc_mkdir("fs/ext4", NULL);
5568 
5569 	err = ext4_init_feat_adverts();
5570 	if (err)
5571 		goto out4;
5572 
5573 	err = ext4_init_mballoc();
5574 	if (err)
5575 		goto out2;
5576 	else
5577 		ext4_mballoc_ready = 1;
5578 	err = init_inodecache();
5579 	if (err)
5580 		goto out1;
5581 	register_as_ext3();
5582 	register_as_ext2();
5583 	err = register_filesystem(&ext4_fs_type);
5584 	if (err)
5585 		goto out;
5586 
5587 	return 0;
5588 out:
5589 	unregister_as_ext2();
5590 	unregister_as_ext3();
5591 	destroy_inodecache();
5592 out1:
5593 	ext4_mballoc_ready = 0;
5594 	ext4_exit_mballoc();
5595 out2:
5596 	ext4_exit_feat_adverts();
5597 out4:
5598 	if (ext4_proc_root)
5599 		remove_proc_entry("fs/ext4", NULL);
5600 	kset_unregister(ext4_kset);
5601 out5:
5602 	ext4_exit_system_zone();
5603 out6:
5604 	ext4_exit_pageio();
5605 out7:
5606 	ext4_exit_es();
5607 
5608 	return err;
5609 }
5610 
5611 static void __exit ext4_exit_fs(void)
5612 {
5613 	ext4_destroy_lazyinit_thread();
5614 	unregister_as_ext2();
5615 	unregister_as_ext3();
5616 	unregister_filesystem(&ext4_fs_type);
5617 	destroy_inodecache();
5618 	ext4_exit_mballoc();
5619 	ext4_exit_feat_adverts();
5620 	remove_proc_entry("fs/ext4", NULL);
5621 	kset_unregister(ext4_kset);
5622 	ext4_exit_system_zone();
5623 	ext4_exit_pageio();
5624 	ext4_exit_es();
5625 }
5626 
5627 MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
5628 MODULE_DESCRIPTION("Fourth Extended Filesystem");
5629 MODULE_LICENSE("GPL");
5630 module_init(ext4_init_fs)
5631 module_exit(ext4_exit_fs)
5632