xref: /linux/fs/ext4/super.c (revision 7518f0763ecd6232ccad379e56e45b799d2d1a4c)
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"
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 
63 static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
64 			     unsigned long journal_devnum);
65 static int ext4_show_options(struct seq_file *seq, struct dentry *root);
66 static int ext4_commit_super(struct super_block *sb, int sync);
67 static void ext4_mark_recovery_complete(struct super_block *sb,
68 					struct ext4_super_block *es);
69 static void ext4_clear_journal_err(struct super_block *sb,
70 				   struct ext4_super_block *es);
71 static int ext4_sync_fs(struct super_block *sb, int wait);
72 static const char *ext4_decode_error(struct super_block *sb, int errno,
73 				     char nbuf[16]);
74 static int ext4_remount(struct super_block *sb, int *flags, char *data);
75 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf);
76 static int ext4_unfreeze(struct super_block *sb);
77 static int ext4_freeze(struct super_block *sb);
78 static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
79 		       const char *dev_name, void *data);
80 static inline int ext2_feature_set_ok(struct super_block *sb);
81 static inline int ext3_feature_set_ok(struct super_block *sb);
82 static int ext4_feature_set_ok(struct super_block *sb, int readonly);
83 static void ext4_destroy_lazyinit_thread(void);
84 static void ext4_unregister_li_request(struct super_block *sb);
85 static void ext4_clear_request_list(void);
86 
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 #define IS_EXT2_SB(sb) ((sb)->s_bdev->bd_holder == &ext2_fs_type)
96 #else
97 #define IS_EXT2_SB(sb) (0)
98 #endif
99 
100 
101 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
102 static struct file_system_type ext3_fs_type = {
103 	.owner		= THIS_MODULE,
104 	.name		= "ext3",
105 	.mount		= ext4_mount,
106 	.kill_sb	= kill_block_super,
107 	.fs_flags	= FS_REQUIRES_DEV,
108 };
109 #define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type)
110 #else
111 #define IS_EXT3_SB(sb) (0)
112 #endif
113 
114 static int ext4_verify_csum_type(struct super_block *sb,
115 				 struct ext4_super_block *es)
116 {
117 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
118 					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
119 		return 1;
120 
121 	return es->s_checksum_type == EXT4_CRC32C_CHKSUM;
122 }
123 
124 static __le32 ext4_superblock_csum(struct super_block *sb,
125 				   struct ext4_super_block *es)
126 {
127 	struct ext4_sb_info *sbi = EXT4_SB(sb);
128 	int offset = offsetof(struct ext4_super_block, s_checksum);
129 	__u32 csum;
130 
131 	csum = ext4_chksum(sbi, ~0, (char *)es, offset);
132 
133 	return cpu_to_le32(csum);
134 }
135 
136 int ext4_superblock_csum_verify(struct super_block *sb,
137 				struct ext4_super_block *es)
138 {
139 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
140 				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
141 		return 1;
142 
143 	return es->s_checksum == ext4_superblock_csum(sb, es);
144 }
145 
146 void ext4_superblock_csum_set(struct super_block *sb,
147 			      struct ext4_super_block *es)
148 {
149 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
150 		EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
151 		return;
152 
153 	es->s_checksum = ext4_superblock_csum(sb, es);
154 }
155 
156 void *ext4_kvmalloc(size_t size, gfp_t flags)
157 {
158 	void *ret;
159 
160 	ret = kmalloc(size, flags);
161 	if (!ret)
162 		ret = __vmalloc(size, flags, PAGE_KERNEL);
163 	return ret;
164 }
165 
166 void *ext4_kvzalloc(size_t size, gfp_t flags)
167 {
168 	void *ret;
169 
170 	ret = kzalloc(size, flags);
171 	if (!ret)
172 		ret = __vmalloc(size, flags | __GFP_ZERO, PAGE_KERNEL);
173 	return ret;
174 }
175 
176 void ext4_kvfree(void *ptr)
177 {
178 	if (is_vmalloc_addr(ptr))
179 		vfree(ptr);
180 	else
181 		kfree(ptr);
182 
183 }
184 
185 ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
186 			       struct ext4_group_desc *bg)
187 {
188 	return le32_to_cpu(bg->bg_block_bitmap_lo) |
189 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
190 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_block_bitmap_hi) << 32 : 0);
191 }
192 
193 ext4_fsblk_t ext4_inode_bitmap(struct super_block *sb,
194 			       struct ext4_group_desc *bg)
195 {
196 	return le32_to_cpu(bg->bg_inode_bitmap_lo) |
197 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
198 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_bitmap_hi) << 32 : 0);
199 }
200 
201 ext4_fsblk_t ext4_inode_table(struct super_block *sb,
202 			      struct ext4_group_desc *bg)
203 {
204 	return le32_to_cpu(bg->bg_inode_table_lo) |
205 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
206 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_table_hi) << 32 : 0);
207 }
208 
209 __u32 ext4_free_group_clusters(struct super_block *sb,
210 			       struct ext4_group_desc *bg)
211 {
212 	return le16_to_cpu(bg->bg_free_blocks_count_lo) |
213 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
214 		 (__u32)le16_to_cpu(bg->bg_free_blocks_count_hi) << 16 : 0);
215 }
216 
217 __u32 ext4_free_inodes_count(struct super_block *sb,
218 			      struct ext4_group_desc *bg)
219 {
220 	return le16_to_cpu(bg->bg_free_inodes_count_lo) |
221 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
222 		 (__u32)le16_to_cpu(bg->bg_free_inodes_count_hi) << 16 : 0);
223 }
224 
225 __u32 ext4_used_dirs_count(struct super_block *sb,
226 			      struct ext4_group_desc *bg)
227 {
228 	return le16_to_cpu(bg->bg_used_dirs_count_lo) |
229 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
230 		 (__u32)le16_to_cpu(bg->bg_used_dirs_count_hi) << 16 : 0);
231 }
232 
233 __u32 ext4_itable_unused_count(struct super_block *sb,
234 			      struct ext4_group_desc *bg)
235 {
236 	return le16_to_cpu(bg->bg_itable_unused_lo) |
237 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
238 		 (__u32)le16_to_cpu(bg->bg_itable_unused_hi) << 16 : 0);
239 }
240 
241 void ext4_block_bitmap_set(struct super_block *sb,
242 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
243 {
244 	bg->bg_block_bitmap_lo = cpu_to_le32((u32)blk);
245 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
246 		bg->bg_block_bitmap_hi = cpu_to_le32(blk >> 32);
247 }
248 
249 void ext4_inode_bitmap_set(struct super_block *sb,
250 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
251 {
252 	bg->bg_inode_bitmap_lo  = cpu_to_le32((u32)blk);
253 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
254 		bg->bg_inode_bitmap_hi = cpu_to_le32(blk >> 32);
255 }
256 
257 void ext4_inode_table_set(struct super_block *sb,
258 			  struct ext4_group_desc *bg, ext4_fsblk_t blk)
259 {
260 	bg->bg_inode_table_lo = cpu_to_le32((u32)blk);
261 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
262 		bg->bg_inode_table_hi = cpu_to_le32(blk >> 32);
263 }
264 
265 void ext4_free_group_clusters_set(struct super_block *sb,
266 				  struct ext4_group_desc *bg, __u32 count)
267 {
268 	bg->bg_free_blocks_count_lo = cpu_to_le16((__u16)count);
269 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
270 		bg->bg_free_blocks_count_hi = cpu_to_le16(count >> 16);
271 }
272 
273 void ext4_free_inodes_set(struct super_block *sb,
274 			  struct ext4_group_desc *bg, __u32 count)
275 {
276 	bg->bg_free_inodes_count_lo = cpu_to_le16((__u16)count);
277 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
278 		bg->bg_free_inodes_count_hi = cpu_to_le16(count >> 16);
279 }
280 
281 void ext4_used_dirs_set(struct super_block *sb,
282 			  struct ext4_group_desc *bg, __u32 count)
283 {
284 	bg->bg_used_dirs_count_lo = cpu_to_le16((__u16)count);
285 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
286 		bg->bg_used_dirs_count_hi = cpu_to_le16(count >> 16);
287 }
288 
289 void ext4_itable_unused_set(struct super_block *sb,
290 			  struct ext4_group_desc *bg, __u32 count)
291 {
292 	bg->bg_itable_unused_lo = cpu_to_le16((__u16)count);
293 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
294 		bg->bg_itable_unused_hi = cpu_to_le16(count >> 16);
295 }
296 
297 
298 /* Just increment the non-pointer handle value */
299 static handle_t *ext4_get_nojournal(void)
300 {
301 	handle_t *handle = current->journal_info;
302 	unsigned long ref_cnt = (unsigned long)handle;
303 
304 	BUG_ON(ref_cnt >= EXT4_NOJOURNAL_MAX_REF_COUNT);
305 
306 	ref_cnt++;
307 	handle = (handle_t *)ref_cnt;
308 
309 	current->journal_info = handle;
310 	return handle;
311 }
312 
313 
314 /* Decrement the non-pointer handle value */
315 static void ext4_put_nojournal(handle_t *handle)
316 {
317 	unsigned long ref_cnt = (unsigned long)handle;
318 
319 	BUG_ON(ref_cnt == 0);
320 
321 	ref_cnt--;
322 	handle = (handle_t *)ref_cnt;
323 
324 	current->journal_info = handle;
325 }
326 
327 /*
328  * Wrappers for jbd2_journal_start/end.
329  */
330 handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
331 {
332 	journal_t *journal;
333 
334 	trace_ext4_journal_start(sb, nblocks, _RET_IP_);
335 	if (sb->s_flags & MS_RDONLY)
336 		return ERR_PTR(-EROFS);
337 
338 	WARN_ON(sb->s_writers.frozen == SB_FREEZE_COMPLETE);
339 	journal = EXT4_SB(sb)->s_journal;
340 	if (!journal)
341 		return ext4_get_nojournal();
342 	/*
343 	 * Special case here: if the journal has aborted behind our
344 	 * backs (eg. EIO in the commit thread), then we still need to
345 	 * take the FS itself readonly cleanly.
346 	 */
347 	if (is_journal_aborted(journal)) {
348 		ext4_abort(sb, "Detected aborted journal");
349 		return ERR_PTR(-EROFS);
350 	}
351 	return jbd2_journal_start(journal, nblocks);
352 }
353 
354 int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle)
355 {
356 	struct super_block *sb;
357 	int err;
358 	int rc;
359 
360 	if (!ext4_handle_valid(handle)) {
361 		ext4_put_nojournal(handle);
362 		return 0;
363 	}
364 	sb = handle->h_transaction->t_journal->j_private;
365 	err = handle->h_err;
366 	rc = jbd2_journal_stop(handle);
367 
368 	if (!err)
369 		err = rc;
370 	if (err)
371 		__ext4_std_error(sb, where, line, err);
372 	return err;
373 }
374 
375 void ext4_journal_abort_handle(const char *caller, unsigned int line,
376 			       const char *err_fn, struct buffer_head *bh,
377 			       handle_t *handle, int err)
378 {
379 	char nbuf[16];
380 	const char *errstr = ext4_decode_error(NULL, err, nbuf);
381 
382 	BUG_ON(!ext4_handle_valid(handle));
383 
384 	if (bh)
385 		BUFFER_TRACE(bh, "abort");
386 
387 	if (!handle->h_err)
388 		handle->h_err = err;
389 
390 	if (is_handle_aborted(handle))
391 		return;
392 
393 	printk(KERN_ERR "EXT4-fs: %s:%d: aborting transaction: %s in %s\n",
394 	       caller, line, errstr, err_fn);
395 
396 	jbd2_journal_abort_handle(handle);
397 }
398 
399 static void __save_error_info(struct super_block *sb, const char *func,
400 			    unsigned int line)
401 {
402 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
403 
404 	EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
405 	es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
406 	es->s_last_error_time = cpu_to_le32(get_seconds());
407 	strncpy(es->s_last_error_func, func, sizeof(es->s_last_error_func));
408 	es->s_last_error_line = cpu_to_le32(line);
409 	if (!es->s_first_error_time) {
410 		es->s_first_error_time = es->s_last_error_time;
411 		strncpy(es->s_first_error_func, func,
412 			sizeof(es->s_first_error_func));
413 		es->s_first_error_line = cpu_to_le32(line);
414 		es->s_first_error_ino = es->s_last_error_ino;
415 		es->s_first_error_block = es->s_last_error_block;
416 	}
417 	/*
418 	 * Start the daily error reporting function if it hasn't been
419 	 * started already
420 	 */
421 	if (!es->s_error_count)
422 		mod_timer(&EXT4_SB(sb)->s_err_report, jiffies + 24*60*60*HZ);
423 	le32_add_cpu(&es->s_error_count, 1);
424 }
425 
426 static void save_error_info(struct super_block *sb, const char *func,
427 			    unsigned int line)
428 {
429 	__save_error_info(sb, func, line);
430 	ext4_commit_super(sb, 1);
431 }
432 
433 /*
434  * The del_gendisk() function uninitializes the disk-specific data
435  * structures, including the bdi structure, without telling anyone
436  * else.  Once this happens, any attempt to call mark_buffer_dirty()
437  * (for example, by ext4_commit_super), will cause a kernel OOPS.
438  * This is a kludge to prevent these oops until we can put in a proper
439  * hook in del_gendisk() to inform the VFS and file system layers.
440  */
441 static int block_device_ejected(struct super_block *sb)
442 {
443 	struct inode *bd_inode = sb->s_bdev->bd_inode;
444 	struct backing_dev_info *bdi = bd_inode->i_mapping->backing_dev_info;
445 
446 	return bdi->dev == NULL;
447 }
448 
449 static void ext4_journal_commit_callback(journal_t *journal, transaction_t *txn)
450 {
451 	struct super_block		*sb = journal->j_private;
452 	struct ext4_sb_info		*sbi = EXT4_SB(sb);
453 	int				error = is_journal_aborted(journal);
454 	struct ext4_journal_cb_entry	*jce, *tmp;
455 
456 	spin_lock(&sbi->s_md_lock);
457 	list_for_each_entry_safe(jce, tmp, &txn->t_private_list, jce_list) {
458 		list_del_init(&jce->jce_list);
459 		spin_unlock(&sbi->s_md_lock);
460 		jce->jce_func(sb, jce, error);
461 		spin_lock(&sbi->s_md_lock);
462 	}
463 	spin_unlock(&sbi->s_md_lock);
464 }
465 
466 /* Deal with the reporting of failure conditions on a filesystem such as
467  * inconsistencies detected or read IO failures.
468  *
469  * On ext2, we can store the error state of the filesystem in the
470  * superblock.  That is not possible on ext4, because we may have other
471  * write ordering constraints on the superblock which prevent us from
472  * writing it out straight away; and given that the journal is about to
473  * be aborted, we can't rely on the current, or future, transactions to
474  * write out the superblock safely.
475  *
476  * We'll just use the jbd2_journal_abort() error code to record an error in
477  * the journal instead.  On recovery, the journal will complain about
478  * that error until we've noted it down and cleared it.
479  */
480 
481 static void ext4_handle_error(struct super_block *sb)
482 {
483 	if (sb->s_flags & MS_RDONLY)
484 		return;
485 
486 	if (!test_opt(sb, ERRORS_CONT)) {
487 		journal_t *journal = EXT4_SB(sb)->s_journal;
488 
489 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
490 		if (journal)
491 			jbd2_journal_abort(journal, -EIO);
492 	}
493 	if (test_opt(sb, ERRORS_RO)) {
494 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
495 		sb->s_flags |= MS_RDONLY;
496 	}
497 	if (test_opt(sb, ERRORS_PANIC))
498 		panic("EXT4-fs (device %s): panic forced after error\n",
499 			sb->s_id);
500 }
501 
502 void __ext4_error(struct super_block *sb, const char *function,
503 		  unsigned int line, const char *fmt, ...)
504 {
505 	struct va_format vaf;
506 	va_list args;
507 
508 	va_start(args, fmt);
509 	vaf.fmt = fmt;
510 	vaf.va = &args;
511 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: comm %s: %pV\n",
512 	       sb->s_id, function, line, current->comm, &vaf);
513 	va_end(args);
514 	save_error_info(sb, function, line);
515 
516 	ext4_handle_error(sb);
517 }
518 
519 void ext4_error_inode(struct inode *inode, const char *function,
520 		      unsigned int line, ext4_fsblk_t block,
521 		      const char *fmt, ...)
522 {
523 	va_list args;
524 	struct va_format vaf;
525 	struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
526 
527 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
528 	es->s_last_error_block = cpu_to_le64(block);
529 	save_error_info(inode->i_sb, function, line);
530 	va_start(args, fmt);
531 	vaf.fmt = fmt;
532 	vaf.va = &args;
533 	if (block)
534 		printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
535 		       "inode #%lu: block %llu: comm %s: %pV\n",
536 		       inode->i_sb->s_id, function, line, inode->i_ino,
537 		       block, current->comm, &vaf);
538 	else
539 		printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
540 		       "inode #%lu: comm %s: %pV\n",
541 		       inode->i_sb->s_id, function, line, inode->i_ino,
542 		       current->comm, &vaf);
543 	va_end(args);
544 
545 	ext4_handle_error(inode->i_sb);
546 }
547 
548 void ext4_error_file(struct file *file, const char *function,
549 		     unsigned int line, ext4_fsblk_t block,
550 		     const char *fmt, ...)
551 {
552 	va_list args;
553 	struct va_format vaf;
554 	struct ext4_super_block *es;
555 	struct inode *inode = file->f_dentry->d_inode;
556 	char pathname[80], *path;
557 
558 	es = EXT4_SB(inode->i_sb)->s_es;
559 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
560 	save_error_info(inode->i_sb, function, line);
561 	path = d_path(&(file->f_path), pathname, sizeof(pathname));
562 	if (IS_ERR(path))
563 		path = "(unknown)";
564 	va_start(args, fmt);
565 	vaf.fmt = fmt;
566 	vaf.va = &args;
567 	if (block)
568 		printk(KERN_CRIT
569 		       "EXT4-fs error (device %s): %s:%d: inode #%lu: "
570 		       "block %llu: comm %s: path %s: %pV\n",
571 		       inode->i_sb->s_id, function, line, inode->i_ino,
572 		       block, current->comm, path, &vaf);
573 	else
574 		printk(KERN_CRIT
575 		       "EXT4-fs error (device %s): %s:%d: inode #%lu: "
576 		       "comm %s: path %s: %pV\n",
577 		       inode->i_sb->s_id, function, line, inode->i_ino,
578 		       current->comm, path, &vaf);
579 	va_end(args);
580 
581 	ext4_handle_error(inode->i_sb);
582 }
583 
584 static const char *ext4_decode_error(struct super_block *sb, int errno,
585 				     char nbuf[16])
586 {
587 	char *errstr = NULL;
588 
589 	switch (errno) {
590 	case -EIO:
591 		errstr = "IO failure";
592 		break;
593 	case -ENOMEM:
594 		errstr = "Out of memory";
595 		break;
596 	case -EROFS:
597 		if (!sb || (EXT4_SB(sb)->s_journal &&
598 			    EXT4_SB(sb)->s_journal->j_flags & JBD2_ABORT))
599 			errstr = "Journal has aborted";
600 		else
601 			errstr = "Readonly filesystem";
602 		break;
603 	default:
604 		/* If the caller passed in an extra buffer for unknown
605 		 * errors, textualise them now.  Else we just return
606 		 * NULL. */
607 		if (nbuf) {
608 			/* Check for truncated error codes... */
609 			if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
610 				errstr = nbuf;
611 		}
612 		break;
613 	}
614 
615 	return errstr;
616 }
617 
618 /* __ext4_std_error decodes expected errors from journaling functions
619  * automatically and invokes the appropriate error response.  */
620 
621 void __ext4_std_error(struct super_block *sb, const char *function,
622 		      unsigned int line, int errno)
623 {
624 	char nbuf[16];
625 	const char *errstr;
626 
627 	/* Special case: if the error is EROFS, and we're not already
628 	 * inside a transaction, then there's really no point in logging
629 	 * an error. */
630 	if (errno == -EROFS && journal_current_handle() == NULL &&
631 	    (sb->s_flags & MS_RDONLY))
632 		return;
633 
634 	errstr = ext4_decode_error(sb, errno, nbuf);
635 	printk(KERN_CRIT "EXT4-fs error (device %s) in %s:%d: %s\n",
636 	       sb->s_id, function, line, errstr);
637 	save_error_info(sb, function, line);
638 
639 	ext4_handle_error(sb);
640 }
641 
642 /*
643  * ext4_abort is a much stronger failure handler than ext4_error.  The
644  * abort function may be used to deal with unrecoverable failures such
645  * as journal IO errors or ENOMEM at a critical moment in log management.
646  *
647  * We unconditionally force the filesystem into an ABORT|READONLY state,
648  * unless the error response on the fs has been set to panic in which
649  * case we take the easy way out and panic immediately.
650  */
651 
652 void __ext4_abort(struct super_block *sb, const char *function,
653 		unsigned int line, const char *fmt, ...)
654 {
655 	va_list args;
656 
657 	save_error_info(sb, function, line);
658 	va_start(args, fmt);
659 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: ", sb->s_id,
660 	       function, line);
661 	vprintk(fmt, args);
662 	printk("\n");
663 	va_end(args);
664 
665 	if ((sb->s_flags & MS_RDONLY) == 0) {
666 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
667 		sb->s_flags |= MS_RDONLY;
668 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
669 		if (EXT4_SB(sb)->s_journal)
670 			jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
671 		save_error_info(sb, function, line);
672 	}
673 	if (test_opt(sb, ERRORS_PANIC))
674 		panic("EXT4-fs panic from previous error\n");
675 }
676 
677 void ext4_msg(struct super_block *sb, const char *prefix, const char *fmt, ...)
678 {
679 	struct va_format vaf;
680 	va_list args;
681 
682 	va_start(args, fmt);
683 	vaf.fmt = fmt;
684 	vaf.va = &args;
685 	printk("%sEXT4-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
686 	va_end(args);
687 }
688 
689 void __ext4_warning(struct super_block *sb, const char *function,
690 		    unsigned int line, const char *fmt, ...)
691 {
692 	struct va_format vaf;
693 	va_list args;
694 
695 	va_start(args, fmt);
696 	vaf.fmt = fmt;
697 	vaf.va = &args;
698 	printk(KERN_WARNING "EXT4-fs warning (device %s): %s:%d: %pV\n",
699 	       sb->s_id, function, line, &vaf);
700 	va_end(args);
701 }
702 
703 void __ext4_grp_locked_error(const char *function, unsigned int line,
704 			     struct super_block *sb, ext4_group_t grp,
705 			     unsigned long ino, ext4_fsblk_t block,
706 			     const char *fmt, ...)
707 __releases(bitlock)
708 __acquires(bitlock)
709 {
710 	struct va_format vaf;
711 	va_list args;
712 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
713 
714 	es->s_last_error_ino = cpu_to_le32(ino);
715 	es->s_last_error_block = cpu_to_le64(block);
716 	__save_error_info(sb, function, line);
717 
718 	va_start(args, fmt);
719 
720 	vaf.fmt = fmt;
721 	vaf.va = &args;
722 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: group %u, ",
723 	       sb->s_id, function, line, grp);
724 	if (ino)
725 		printk(KERN_CONT "inode %lu: ", ino);
726 	if (block)
727 		printk(KERN_CONT "block %llu:", (unsigned long long) block);
728 	printk(KERN_CONT "%pV\n", &vaf);
729 	va_end(args);
730 
731 	if (test_opt(sb, ERRORS_CONT)) {
732 		ext4_commit_super(sb, 0);
733 		return;
734 	}
735 
736 	ext4_unlock_group(sb, grp);
737 	ext4_handle_error(sb);
738 	/*
739 	 * We only get here in the ERRORS_RO case; relocking the group
740 	 * may be dangerous, but nothing bad will happen since the
741 	 * filesystem will have already been marked read/only and the
742 	 * journal has been aborted.  We return 1 as a hint to callers
743 	 * who might what to use the return value from
744 	 * ext4_grp_locked_error() to distinguish between the
745 	 * ERRORS_CONT and ERRORS_RO case, and perhaps return more
746 	 * aggressively from the ext4 function in question, with a
747 	 * more appropriate error code.
748 	 */
749 	ext4_lock_group(sb, grp);
750 	return;
751 }
752 
753 void ext4_update_dynamic_rev(struct super_block *sb)
754 {
755 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
756 
757 	if (le32_to_cpu(es->s_rev_level) > EXT4_GOOD_OLD_REV)
758 		return;
759 
760 	ext4_warning(sb,
761 		     "updating to rev %d because of new feature flag, "
762 		     "running e2fsck is recommended",
763 		     EXT4_DYNAMIC_REV);
764 
765 	es->s_first_ino = cpu_to_le32(EXT4_GOOD_OLD_FIRST_INO);
766 	es->s_inode_size = cpu_to_le16(EXT4_GOOD_OLD_INODE_SIZE);
767 	es->s_rev_level = cpu_to_le32(EXT4_DYNAMIC_REV);
768 	/* leave es->s_feature_*compat flags alone */
769 	/* es->s_uuid will be set by e2fsck if empty */
770 
771 	/*
772 	 * The rest of the superblock fields should be zero, and if not it
773 	 * means they are likely already in use, so leave them alone.  We
774 	 * can leave it up to e2fsck to clean up any inconsistencies there.
775 	 */
776 }
777 
778 /*
779  * Open the external journal device
780  */
781 static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb)
782 {
783 	struct block_device *bdev;
784 	char b[BDEVNAME_SIZE];
785 
786 	bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb);
787 	if (IS_ERR(bdev))
788 		goto fail;
789 	return bdev;
790 
791 fail:
792 	ext4_msg(sb, KERN_ERR, "failed to open journal device %s: %ld",
793 			__bdevname(dev, b), PTR_ERR(bdev));
794 	return NULL;
795 }
796 
797 /*
798  * Release the journal device
799  */
800 static int ext4_blkdev_put(struct block_device *bdev)
801 {
802 	return blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
803 }
804 
805 static int ext4_blkdev_remove(struct ext4_sb_info *sbi)
806 {
807 	struct block_device *bdev;
808 	int ret = -ENODEV;
809 
810 	bdev = sbi->journal_bdev;
811 	if (bdev) {
812 		ret = ext4_blkdev_put(bdev);
813 		sbi->journal_bdev = NULL;
814 	}
815 	return ret;
816 }
817 
818 static inline struct inode *orphan_list_entry(struct list_head *l)
819 {
820 	return &list_entry(l, struct ext4_inode_info, i_orphan)->vfs_inode;
821 }
822 
823 static void dump_orphan_list(struct super_block *sb, struct ext4_sb_info *sbi)
824 {
825 	struct list_head *l;
826 
827 	ext4_msg(sb, KERN_ERR, "sb orphan head is %d",
828 		 le32_to_cpu(sbi->s_es->s_last_orphan));
829 
830 	printk(KERN_ERR "sb_info orphan list:\n");
831 	list_for_each(l, &sbi->s_orphan) {
832 		struct inode *inode = orphan_list_entry(l);
833 		printk(KERN_ERR "  "
834 		       "inode %s:%lu at %p: mode %o, nlink %d, next %d\n",
835 		       inode->i_sb->s_id, inode->i_ino, inode,
836 		       inode->i_mode, inode->i_nlink,
837 		       NEXT_ORPHAN(inode));
838 	}
839 }
840 
841 static void ext4_put_super(struct super_block *sb)
842 {
843 	struct ext4_sb_info *sbi = EXT4_SB(sb);
844 	struct ext4_super_block *es = sbi->s_es;
845 	int i, err;
846 
847 	ext4_unregister_li_request(sb);
848 	dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
849 
850 	flush_workqueue(sbi->dio_unwritten_wq);
851 	destroy_workqueue(sbi->dio_unwritten_wq);
852 
853 	if (sbi->s_journal) {
854 		err = jbd2_journal_destroy(sbi->s_journal);
855 		sbi->s_journal = NULL;
856 		if (err < 0)
857 			ext4_abort(sb, "Couldn't clean up the journal");
858 	}
859 
860 	del_timer(&sbi->s_err_report);
861 	ext4_release_system_zone(sb);
862 	ext4_mb_release(sb);
863 	ext4_ext_release(sb);
864 	ext4_xattr_put_super(sb);
865 
866 	if (!(sb->s_flags & MS_RDONLY)) {
867 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
868 		es->s_state = cpu_to_le16(sbi->s_mount_state);
869 	}
870 	if (!(sb->s_flags & MS_RDONLY))
871 		ext4_commit_super(sb, 1);
872 
873 	if (sbi->s_proc) {
874 		remove_proc_entry("options", sbi->s_proc);
875 		remove_proc_entry(sb->s_id, ext4_proc_root);
876 	}
877 	kobject_del(&sbi->s_kobj);
878 
879 	for (i = 0; i < sbi->s_gdb_count; i++)
880 		brelse(sbi->s_group_desc[i]);
881 	ext4_kvfree(sbi->s_group_desc);
882 	ext4_kvfree(sbi->s_flex_groups);
883 	percpu_counter_destroy(&sbi->s_freeclusters_counter);
884 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
885 	percpu_counter_destroy(&sbi->s_dirs_counter);
886 	percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
887 	brelse(sbi->s_sbh);
888 #ifdef CONFIG_QUOTA
889 	for (i = 0; i < MAXQUOTAS; i++)
890 		kfree(sbi->s_qf_names[i]);
891 #endif
892 
893 	/* Debugging code just in case the in-memory inode orphan list
894 	 * isn't empty.  The on-disk one can be non-empty if we've
895 	 * detected an error and taken the fs readonly, but the
896 	 * in-memory list had better be clean by this point. */
897 	if (!list_empty(&sbi->s_orphan))
898 		dump_orphan_list(sb, sbi);
899 	J_ASSERT(list_empty(&sbi->s_orphan));
900 
901 	invalidate_bdev(sb->s_bdev);
902 	if (sbi->journal_bdev && sbi->journal_bdev != sb->s_bdev) {
903 		/*
904 		 * Invalidate the journal device's buffers.  We don't want them
905 		 * floating about in memory - the physical journal device may
906 		 * hotswapped, and it breaks the `ro-after' testing code.
907 		 */
908 		sync_blockdev(sbi->journal_bdev);
909 		invalidate_bdev(sbi->journal_bdev);
910 		ext4_blkdev_remove(sbi);
911 	}
912 	if (sbi->s_mmp_tsk)
913 		kthread_stop(sbi->s_mmp_tsk);
914 	sb->s_fs_info = NULL;
915 	/*
916 	 * Now that we are completely done shutting down the
917 	 * superblock, we need to actually destroy the kobject.
918 	 */
919 	kobject_put(&sbi->s_kobj);
920 	wait_for_completion(&sbi->s_kobj_unregister);
921 	if (sbi->s_chksum_driver)
922 		crypto_free_shash(sbi->s_chksum_driver);
923 	kfree(sbi->s_blockgroup_lock);
924 	kfree(sbi);
925 }
926 
927 static struct kmem_cache *ext4_inode_cachep;
928 
929 /*
930  * Called inside transaction, so use GFP_NOFS
931  */
932 static struct inode *ext4_alloc_inode(struct super_block *sb)
933 {
934 	struct ext4_inode_info *ei;
935 
936 	ei = kmem_cache_alloc(ext4_inode_cachep, GFP_NOFS);
937 	if (!ei)
938 		return NULL;
939 
940 	ei->vfs_inode.i_version = 1;
941 	ei->vfs_inode.i_data.writeback_index = 0;
942 	memset(&ei->i_cached_extent, 0, sizeof(struct ext4_ext_cache));
943 	INIT_LIST_HEAD(&ei->i_prealloc_list);
944 	spin_lock_init(&ei->i_prealloc_lock);
945 	ei->i_reserved_data_blocks = 0;
946 	ei->i_reserved_meta_blocks = 0;
947 	ei->i_allocated_meta_blocks = 0;
948 	ei->i_da_metadata_calc_len = 0;
949 	ei->i_da_metadata_calc_last_lblock = 0;
950 	spin_lock_init(&(ei->i_block_reservation_lock));
951 #ifdef CONFIG_QUOTA
952 	ei->i_reserved_quota = 0;
953 #endif
954 	ei->jinode = NULL;
955 	INIT_LIST_HEAD(&ei->i_completed_io_list);
956 	spin_lock_init(&ei->i_completed_io_lock);
957 	ei->i_sync_tid = 0;
958 	ei->i_datasync_tid = 0;
959 	atomic_set(&ei->i_ioend_count, 0);
960 	atomic_set(&ei->i_unwritten, 0);
961 
962 	return &ei->vfs_inode;
963 }
964 
965 static int ext4_drop_inode(struct inode *inode)
966 {
967 	int drop = generic_drop_inode(inode);
968 
969 	trace_ext4_drop_inode(inode, drop);
970 	return drop;
971 }
972 
973 static void ext4_i_callback(struct rcu_head *head)
974 {
975 	struct inode *inode = container_of(head, struct inode, i_rcu);
976 	kmem_cache_free(ext4_inode_cachep, EXT4_I(inode));
977 }
978 
979 static void ext4_destroy_inode(struct inode *inode)
980 {
981 	if (!list_empty(&(EXT4_I(inode)->i_orphan))) {
982 		ext4_msg(inode->i_sb, KERN_ERR,
983 			 "Inode %lu (%p): orphan list check failed!",
984 			 inode->i_ino, EXT4_I(inode));
985 		print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 16, 4,
986 				EXT4_I(inode), sizeof(struct ext4_inode_info),
987 				true);
988 		dump_stack();
989 	}
990 	call_rcu(&inode->i_rcu, ext4_i_callback);
991 }
992 
993 static void init_once(void *foo)
994 {
995 	struct ext4_inode_info *ei = (struct ext4_inode_info *) foo;
996 
997 	INIT_LIST_HEAD(&ei->i_orphan);
998 #ifdef CONFIG_EXT4_FS_XATTR
999 	init_rwsem(&ei->xattr_sem);
1000 #endif
1001 	init_rwsem(&ei->i_data_sem);
1002 	inode_init_once(&ei->vfs_inode);
1003 }
1004 
1005 static int init_inodecache(void)
1006 {
1007 	ext4_inode_cachep = kmem_cache_create("ext4_inode_cache",
1008 					     sizeof(struct ext4_inode_info),
1009 					     0, (SLAB_RECLAIM_ACCOUNT|
1010 						SLAB_MEM_SPREAD),
1011 					     init_once);
1012 	if (ext4_inode_cachep == NULL)
1013 		return -ENOMEM;
1014 	return 0;
1015 }
1016 
1017 static void destroy_inodecache(void)
1018 {
1019 	/*
1020 	 * Make sure all delayed rcu free inodes are flushed before we
1021 	 * destroy cache.
1022 	 */
1023 	rcu_barrier();
1024 	kmem_cache_destroy(ext4_inode_cachep);
1025 }
1026 
1027 void ext4_clear_inode(struct inode *inode)
1028 {
1029 	invalidate_inode_buffers(inode);
1030 	clear_inode(inode);
1031 	dquot_drop(inode);
1032 	ext4_discard_preallocations(inode);
1033 	if (EXT4_I(inode)->jinode) {
1034 		jbd2_journal_release_jbd_inode(EXT4_JOURNAL(inode),
1035 					       EXT4_I(inode)->jinode);
1036 		jbd2_free_inode(EXT4_I(inode)->jinode);
1037 		EXT4_I(inode)->jinode = NULL;
1038 	}
1039 }
1040 
1041 static struct inode *ext4_nfs_get_inode(struct super_block *sb,
1042 					u64 ino, u32 generation)
1043 {
1044 	struct inode *inode;
1045 
1046 	if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
1047 		return ERR_PTR(-ESTALE);
1048 	if (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
1049 		return ERR_PTR(-ESTALE);
1050 
1051 	/* iget isn't really right if the inode is currently unallocated!!
1052 	 *
1053 	 * ext4_read_inode will return a bad_inode if the inode had been
1054 	 * deleted, so we should be safe.
1055 	 *
1056 	 * Currently we don't know the generation for parent directory, so
1057 	 * a generation of 0 means "accept any"
1058 	 */
1059 	inode = ext4_iget(sb, ino);
1060 	if (IS_ERR(inode))
1061 		return ERR_CAST(inode);
1062 	if (generation && inode->i_generation != generation) {
1063 		iput(inode);
1064 		return ERR_PTR(-ESTALE);
1065 	}
1066 
1067 	return inode;
1068 }
1069 
1070 static struct dentry *ext4_fh_to_dentry(struct super_block *sb, struct fid *fid,
1071 					int fh_len, int fh_type)
1072 {
1073 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
1074 				    ext4_nfs_get_inode);
1075 }
1076 
1077 static struct dentry *ext4_fh_to_parent(struct super_block *sb, struct fid *fid,
1078 					int fh_len, int fh_type)
1079 {
1080 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
1081 				    ext4_nfs_get_inode);
1082 }
1083 
1084 /*
1085  * Try to release metadata pages (indirect blocks, directories) which are
1086  * mapped via the block device.  Since these pages could have journal heads
1087  * which would prevent try_to_free_buffers() from freeing them, we must use
1088  * jbd2 layer's try_to_free_buffers() function to release them.
1089  */
1090 static int bdev_try_to_free_page(struct super_block *sb, struct page *page,
1091 				 gfp_t wait)
1092 {
1093 	journal_t *journal = EXT4_SB(sb)->s_journal;
1094 
1095 	WARN_ON(PageChecked(page));
1096 	if (!page_has_buffers(page))
1097 		return 0;
1098 	if (journal)
1099 		return jbd2_journal_try_to_free_buffers(journal, page,
1100 							wait & ~__GFP_WAIT);
1101 	return try_to_free_buffers(page);
1102 }
1103 
1104 #ifdef CONFIG_QUOTA
1105 #define QTYPE2NAME(t) ((t) == USRQUOTA ? "user" : "group")
1106 #define QTYPE2MOPT(on, t) ((t) == USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
1107 
1108 static int ext4_write_dquot(struct dquot *dquot);
1109 static int ext4_acquire_dquot(struct dquot *dquot);
1110 static int ext4_release_dquot(struct dquot *dquot);
1111 static int ext4_mark_dquot_dirty(struct dquot *dquot);
1112 static int ext4_write_info(struct super_block *sb, int type);
1113 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
1114 			 struct path *path);
1115 static int ext4_quota_on_sysfile(struct super_block *sb, int type,
1116 				 int format_id);
1117 static int ext4_quota_off(struct super_block *sb, int type);
1118 static int ext4_quota_off_sysfile(struct super_block *sb, int type);
1119 static int ext4_quota_on_mount(struct super_block *sb, int type);
1120 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
1121 			       size_t len, loff_t off);
1122 static ssize_t ext4_quota_write(struct super_block *sb, int type,
1123 				const char *data, size_t len, loff_t off);
1124 static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
1125 			     unsigned int flags);
1126 static int ext4_enable_quotas(struct super_block *sb);
1127 
1128 static const struct dquot_operations ext4_quota_operations = {
1129 	.get_reserved_space = ext4_get_reserved_space,
1130 	.write_dquot	= ext4_write_dquot,
1131 	.acquire_dquot	= ext4_acquire_dquot,
1132 	.release_dquot	= ext4_release_dquot,
1133 	.mark_dirty	= ext4_mark_dquot_dirty,
1134 	.write_info	= ext4_write_info,
1135 	.alloc_dquot	= dquot_alloc,
1136 	.destroy_dquot	= dquot_destroy,
1137 };
1138 
1139 static const struct quotactl_ops ext4_qctl_operations = {
1140 	.quota_on	= ext4_quota_on,
1141 	.quota_off	= ext4_quota_off,
1142 	.quota_sync	= dquot_quota_sync,
1143 	.get_info	= dquot_get_dqinfo,
1144 	.set_info	= dquot_set_dqinfo,
1145 	.get_dqblk	= dquot_get_dqblk,
1146 	.set_dqblk	= dquot_set_dqblk
1147 };
1148 
1149 static const struct quotactl_ops ext4_qctl_sysfile_operations = {
1150 	.quota_on_meta	= ext4_quota_on_sysfile,
1151 	.quota_off	= ext4_quota_off_sysfile,
1152 	.quota_sync	= dquot_quota_sync,
1153 	.get_info	= dquot_get_dqinfo,
1154 	.set_info	= dquot_set_dqinfo,
1155 	.get_dqblk	= dquot_get_dqblk,
1156 	.set_dqblk	= dquot_set_dqblk
1157 };
1158 #endif
1159 
1160 static const struct super_operations ext4_sops = {
1161 	.alloc_inode	= ext4_alloc_inode,
1162 	.destroy_inode	= ext4_destroy_inode,
1163 	.write_inode	= ext4_write_inode,
1164 	.dirty_inode	= ext4_dirty_inode,
1165 	.drop_inode	= ext4_drop_inode,
1166 	.evict_inode	= ext4_evict_inode,
1167 	.put_super	= ext4_put_super,
1168 	.sync_fs	= ext4_sync_fs,
1169 	.freeze_fs	= ext4_freeze,
1170 	.unfreeze_fs	= ext4_unfreeze,
1171 	.statfs		= ext4_statfs,
1172 	.remount_fs	= ext4_remount,
1173 	.show_options	= ext4_show_options,
1174 #ifdef CONFIG_QUOTA
1175 	.quota_read	= ext4_quota_read,
1176 	.quota_write	= ext4_quota_write,
1177 #endif
1178 	.bdev_try_to_free_page = bdev_try_to_free_page,
1179 };
1180 
1181 static const struct super_operations ext4_nojournal_sops = {
1182 	.alloc_inode	= ext4_alloc_inode,
1183 	.destroy_inode	= ext4_destroy_inode,
1184 	.write_inode	= ext4_write_inode,
1185 	.dirty_inode	= ext4_dirty_inode,
1186 	.drop_inode	= ext4_drop_inode,
1187 	.evict_inode	= ext4_evict_inode,
1188 	.put_super	= ext4_put_super,
1189 	.statfs		= ext4_statfs,
1190 	.remount_fs	= ext4_remount,
1191 	.show_options	= ext4_show_options,
1192 #ifdef CONFIG_QUOTA
1193 	.quota_read	= ext4_quota_read,
1194 	.quota_write	= ext4_quota_write,
1195 #endif
1196 	.bdev_try_to_free_page = bdev_try_to_free_page,
1197 };
1198 
1199 static const struct export_operations ext4_export_ops = {
1200 	.fh_to_dentry = ext4_fh_to_dentry,
1201 	.fh_to_parent = ext4_fh_to_parent,
1202 	.get_parent = ext4_get_parent,
1203 };
1204 
1205 enum {
1206 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
1207 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
1208 	Opt_nouid32, Opt_debug, Opt_removed,
1209 	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
1210 	Opt_auto_da_alloc, Opt_noauto_da_alloc, Opt_noload,
1211 	Opt_commit, Opt_min_batch_time, Opt_max_batch_time,
1212 	Opt_journal_dev, Opt_journal_checksum, Opt_journal_async_commit,
1213 	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
1214 	Opt_data_err_abort, Opt_data_err_ignore,
1215 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
1216 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
1217 	Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err,
1218 	Opt_usrquota, Opt_grpquota, Opt_i_version,
1219 	Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_mblk_io_submit,
1220 	Opt_nomblk_io_submit, Opt_block_validity, Opt_noblock_validity,
1221 	Opt_inode_readahead_blks, Opt_journal_ioprio,
1222 	Opt_dioread_nolock, Opt_dioread_lock,
1223 	Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
1224 	Opt_max_dir_size_kb,
1225 };
1226 
1227 static const match_table_t tokens = {
1228 	{Opt_bsd_df, "bsddf"},
1229 	{Opt_minix_df, "minixdf"},
1230 	{Opt_grpid, "grpid"},
1231 	{Opt_grpid, "bsdgroups"},
1232 	{Opt_nogrpid, "nogrpid"},
1233 	{Opt_nogrpid, "sysvgroups"},
1234 	{Opt_resgid, "resgid=%u"},
1235 	{Opt_resuid, "resuid=%u"},
1236 	{Opt_sb, "sb=%u"},
1237 	{Opt_err_cont, "errors=continue"},
1238 	{Opt_err_panic, "errors=panic"},
1239 	{Opt_err_ro, "errors=remount-ro"},
1240 	{Opt_nouid32, "nouid32"},
1241 	{Opt_debug, "debug"},
1242 	{Opt_removed, "oldalloc"},
1243 	{Opt_removed, "orlov"},
1244 	{Opt_user_xattr, "user_xattr"},
1245 	{Opt_nouser_xattr, "nouser_xattr"},
1246 	{Opt_acl, "acl"},
1247 	{Opt_noacl, "noacl"},
1248 	{Opt_noload, "norecovery"},
1249 	{Opt_noload, "noload"},
1250 	{Opt_removed, "nobh"},
1251 	{Opt_removed, "bh"},
1252 	{Opt_commit, "commit=%u"},
1253 	{Opt_min_batch_time, "min_batch_time=%u"},
1254 	{Opt_max_batch_time, "max_batch_time=%u"},
1255 	{Opt_journal_dev, "journal_dev=%u"},
1256 	{Opt_journal_checksum, "journal_checksum"},
1257 	{Opt_journal_async_commit, "journal_async_commit"},
1258 	{Opt_abort, "abort"},
1259 	{Opt_data_journal, "data=journal"},
1260 	{Opt_data_ordered, "data=ordered"},
1261 	{Opt_data_writeback, "data=writeback"},
1262 	{Opt_data_err_abort, "data_err=abort"},
1263 	{Opt_data_err_ignore, "data_err=ignore"},
1264 	{Opt_offusrjquota, "usrjquota="},
1265 	{Opt_usrjquota, "usrjquota=%s"},
1266 	{Opt_offgrpjquota, "grpjquota="},
1267 	{Opt_grpjquota, "grpjquota=%s"},
1268 	{Opt_jqfmt_vfsold, "jqfmt=vfsold"},
1269 	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
1270 	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
1271 	{Opt_grpquota, "grpquota"},
1272 	{Opt_noquota, "noquota"},
1273 	{Opt_quota, "quota"},
1274 	{Opt_usrquota, "usrquota"},
1275 	{Opt_barrier, "barrier=%u"},
1276 	{Opt_barrier, "barrier"},
1277 	{Opt_nobarrier, "nobarrier"},
1278 	{Opt_i_version, "i_version"},
1279 	{Opt_stripe, "stripe=%u"},
1280 	{Opt_delalloc, "delalloc"},
1281 	{Opt_nodelalloc, "nodelalloc"},
1282 	{Opt_mblk_io_submit, "mblk_io_submit"},
1283 	{Opt_nomblk_io_submit, "nomblk_io_submit"},
1284 	{Opt_block_validity, "block_validity"},
1285 	{Opt_noblock_validity, "noblock_validity"},
1286 	{Opt_inode_readahead_blks, "inode_readahead_blks=%u"},
1287 	{Opt_journal_ioprio, "journal_ioprio=%u"},
1288 	{Opt_auto_da_alloc, "auto_da_alloc=%u"},
1289 	{Opt_auto_da_alloc, "auto_da_alloc"},
1290 	{Opt_noauto_da_alloc, "noauto_da_alloc"},
1291 	{Opt_dioread_nolock, "dioread_nolock"},
1292 	{Opt_dioread_lock, "dioread_lock"},
1293 	{Opt_discard, "discard"},
1294 	{Opt_nodiscard, "nodiscard"},
1295 	{Opt_init_itable, "init_itable=%u"},
1296 	{Opt_init_itable, "init_itable"},
1297 	{Opt_noinit_itable, "noinit_itable"},
1298 	{Opt_max_dir_size_kb, "max_dir_size_kb=%u"},
1299 	{Opt_removed, "check=none"},	/* mount option from ext2/3 */
1300 	{Opt_removed, "nocheck"},	/* mount option from ext2/3 */
1301 	{Opt_removed, "reservation"},	/* mount option from ext2/3 */
1302 	{Opt_removed, "noreservation"}, /* mount option from ext2/3 */
1303 	{Opt_removed, "journal=%u"},	/* mount option from ext2/3 */
1304 	{Opt_err, NULL},
1305 };
1306 
1307 static ext4_fsblk_t get_sb_block(void **data)
1308 {
1309 	ext4_fsblk_t	sb_block;
1310 	char		*options = (char *) *data;
1311 
1312 	if (!options || strncmp(options, "sb=", 3) != 0)
1313 		return 1;	/* Default location */
1314 
1315 	options += 3;
1316 	/* TODO: use simple_strtoll with >32bit ext4 */
1317 	sb_block = simple_strtoul(options, &options, 0);
1318 	if (*options && *options != ',') {
1319 		printk(KERN_ERR "EXT4-fs: Invalid sb specification: %s\n",
1320 		       (char *) *data);
1321 		return 1;
1322 	}
1323 	if (*options == ',')
1324 		options++;
1325 	*data = (void *) options;
1326 
1327 	return sb_block;
1328 }
1329 
1330 #define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))
1331 static char deprecated_msg[] = "Mount option \"%s\" will be removed by %s\n"
1332 	"Contact linux-ext4@vger.kernel.org if you think we should keep it.\n";
1333 
1334 #ifdef CONFIG_QUOTA
1335 static int set_qf_name(struct super_block *sb, int qtype, substring_t *args)
1336 {
1337 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1338 	char *qname;
1339 
1340 	if (sb_any_quota_loaded(sb) &&
1341 		!sbi->s_qf_names[qtype]) {
1342 		ext4_msg(sb, KERN_ERR,
1343 			"Cannot change journaled "
1344 			"quota options when quota turned on");
1345 		return -1;
1346 	}
1347 	qname = match_strdup(args);
1348 	if (!qname) {
1349 		ext4_msg(sb, KERN_ERR,
1350 			"Not enough memory for storing quotafile name");
1351 		return -1;
1352 	}
1353 	if (sbi->s_qf_names[qtype] &&
1354 		strcmp(sbi->s_qf_names[qtype], qname)) {
1355 		ext4_msg(sb, KERN_ERR,
1356 			"%s quota file already specified", QTYPE2NAME(qtype));
1357 		kfree(qname);
1358 		return -1;
1359 	}
1360 	sbi->s_qf_names[qtype] = qname;
1361 	if (strchr(sbi->s_qf_names[qtype], '/')) {
1362 		ext4_msg(sb, KERN_ERR,
1363 			"quotafile must be on filesystem root");
1364 		kfree(sbi->s_qf_names[qtype]);
1365 		sbi->s_qf_names[qtype] = NULL;
1366 		return -1;
1367 	}
1368 	set_opt(sb, QUOTA);
1369 	return 1;
1370 }
1371 
1372 static int clear_qf_name(struct super_block *sb, int qtype)
1373 {
1374 
1375 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1376 
1377 	if (sb_any_quota_loaded(sb) &&
1378 		sbi->s_qf_names[qtype]) {
1379 		ext4_msg(sb, KERN_ERR, "Cannot change journaled quota options"
1380 			" when quota turned on");
1381 		return -1;
1382 	}
1383 	/*
1384 	 * The space will be released later when all options are confirmed
1385 	 * to be correct
1386 	 */
1387 	sbi->s_qf_names[qtype] = NULL;
1388 	return 1;
1389 }
1390 #endif
1391 
1392 #define MOPT_SET	0x0001
1393 #define MOPT_CLEAR	0x0002
1394 #define MOPT_NOSUPPORT	0x0004
1395 #define MOPT_EXPLICIT	0x0008
1396 #define MOPT_CLEAR_ERR	0x0010
1397 #define MOPT_GTE0	0x0020
1398 #ifdef CONFIG_QUOTA
1399 #define MOPT_Q		0
1400 #define MOPT_QFMT	0x0040
1401 #else
1402 #define MOPT_Q		MOPT_NOSUPPORT
1403 #define MOPT_QFMT	MOPT_NOSUPPORT
1404 #endif
1405 #define MOPT_DATAJ	0x0080
1406 
1407 static const struct mount_opts {
1408 	int	token;
1409 	int	mount_opt;
1410 	int	flags;
1411 } ext4_mount_opts[] = {
1412 	{Opt_minix_df, EXT4_MOUNT_MINIX_DF, MOPT_SET},
1413 	{Opt_bsd_df, EXT4_MOUNT_MINIX_DF, MOPT_CLEAR},
1414 	{Opt_grpid, EXT4_MOUNT_GRPID, MOPT_SET},
1415 	{Opt_nogrpid, EXT4_MOUNT_GRPID, MOPT_CLEAR},
1416 	{Opt_mblk_io_submit, EXT4_MOUNT_MBLK_IO_SUBMIT, MOPT_SET},
1417 	{Opt_nomblk_io_submit, EXT4_MOUNT_MBLK_IO_SUBMIT, MOPT_CLEAR},
1418 	{Opt_block_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_SET},
1419 	{Opt_noblock_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_CLEAR},
1420 	{Opt_dioread_nolock, EXT4_MOUNT_DIOREAD_NOLOCK, MOPT_SET},
1421 	{Opt_dioread_lock, EXT4_MOUNT_DIOREAD_NOLOCK, MOPT_CLEAR},
1422 	{Opt_discard, EXT4_MOUNT_DISCARD, MOPT_SET},
1423 	{Opt_nodiscard, EXT4_MOUNT_DISCARD, MOPT_CLEAR},
1424 	{Opt_delalloc, EXT4_MOUNT_DELALLOC, MOPT_SET | MOPT_EXPLICIT},
1425 	{Opt_nodelalloc, EXT4_MOUNT_DELALLOC, MOPT_CLEAR | MOPT_EXPLICIT},
1426 	{Opt_journal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM, MOPT_SET},
1427 	{Opt_journal_async_commit, (EXT4_MOUNT_JOURNAL_ASYNC_COMMIT |
1428 				    EXT4_MOUNT_JOURNAL_CHECKSUM), MOPT_SET},
1429 	{Opt_noload, EXT4_MOUNT_NOLOAD, MOPT_SET},
1430 	{Opt_err_panic, EXT4_MOUNT_ERRORS_PANIC, MOPT_SET | MOPT_CLEAR_ERR},
1431 	{Opt_err_ro, EXT4_MOUNT_ERRORS_RO, MOPT_SET | MOPT_CLEAR_ERR},
1432 	{Opt_err_cont, EXT4_MOUNT_ERRORS_CONT, MOPT_SET | MOPT_CLEAR_ERR},
1433 	{Opt_data_err_abort, EXT4_MOUNT_DATA_ERR_ABORT, MOPT_SET},
1434 	{Opt_data_err_ignore, EXT4_MOUNT_DATA_ERR_ABORT, MOPT_CLEAR},
1435 	{Opt_barrier, EXT4_MOUNT_BARRIER, MOPT_SET},
1436 	{Opt_nobarrier, EXT4_MOUNT_BARRIER, MOPT_CLEAR},
1437 	{Opt_noauto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_SET},
1438 	{Opt_auto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_CLEAR},
1439 	{Opt_noinit_itable, EXT4_MOUNT_INIT_INODE_TABLE, MOPT_CLEAR},
1440 	{Opt_commit, 0, MOPT_GTE0},
1441 	{Opt_max_batch_time, 0, MOPT_GTE0},
1442 	{Opt_min_batch_time, 0, MOPT_GTE0},
1443 	{Opt_inode_readahead_blks, 0, MOPT_GTE0},
1444 	{Opt_init_itable, 0, MOPT_GTE0},
1445 	{Opt_stripe, 0, MOPT_GTE0},
1446 	{Opt_data_journal, EXT4_MOUNT_JOURNAL_DATA, MOPT_DATAJ},
1447 	{Opt_data_ordered, EXT4_MOUNT_ORDERED_DATA, MOPT_DATAJ},
1448 	{Opt_data_writeback, EXT4_MOUNT_WRITEBACK_DATA, MOPT_DATAJ},
1449 #ifdef CONFIG_EXT4_FS_XATTR
1450 	{Opt_user_xattr, EXT4_MOUNT_XATTR_USER, MOPT_SET},
1451 	{Opt_nouser_xattr, EXT4_MOUNT_XATTR_USER, MOPT_CLEAR},
1452 #else
1453 	{Opt_user_xattr, 0, MOPT_NOSUPPORT},
1454 	{Opt_nouser_xattr, 0, MOPT_NOSUPPORT},
1455 #endif
1456 #ifdef CONFIG_EXT4_FS_POSIX_ACL
1457 	{Opt_acl, EXT4_MOUNT_POSIX_ACL, MOPT_SET},
1458 	{Opt_noacl, EXT4_MOUNT_POSIX_ACL, MOPT_CLEAR},
1459 #else
1460 	{Opt_acl, 0, MOPT_NOSUPPORT},
1461 	{Opt_noacl, 0, MOPT_NOSUPPORT},
1462 #endif
1463 	{Opt_nouid32, EXT4_MOUNT_NO_UID32, MOPT_SET},
1464 	{Opt_debug, EXT4_MOUNT_DEBUG, MOPT_SET},
1465 	{Opt_quota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA, MOPT_SET | MOPT_Q},
1466 	{Opt_usrquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA,
1467 							MOPT_SET | MOPT_Q},
1468 	{Opt_grpquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_GRPQUOTA,
1469 							MOPT_SET | MOPT_Q},
1470 	{Opt_noquota, (EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA |
1471 		       EXT4_MOUNT_GRPQUOTA), MOPT_CLEAR | MOPT_Q},
1472 	{Opt_usrjquota, 0, MOPT_Q},
1473 	{Opt_grpjquota, 0, MOPT_Q},
1474 	{Opt_offusrjquota, 0, MOPT_Q},
1475 	{Opt_offgrpjquota, 0, MOPT_Q},
1476 	{Opt_jqfmt_vfsold, QFMT_VFS_OLD, MOPT_QFMT},
1477 	{Opt_jqfmt_vfsv0, QFMT_VFS_V0, MOPT_QFMT},
1478 	{Opt_jqfmt_vfsv1, QFMT_VFS_V1, MOPT_QFMT},
1479 	{Opt_max_dir_size_kb, 0, MOPT_GTE0},
1480 	{Opt_err, 0, 0}
1481 };
1482 
1483 static int handle_mount_opt(struct super_block *sb, char *opt, int token,
1484 			    substring_t *args, unsigned long *journal_devnum,
1485 			    unsigned int *journal_ioprio, int is_remount)
1486 {
1487 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1488 	const struct mount_opts *m;
1489 	kuid_t uid;
1490 	kgid_t gid;
1491 	int arg = 0;
1492 
1493 #ifdef CONFIG_QUOTA
1494 	if (token == Opt_usrjquota)
1495 		return set_qf_name(sb, USRQUOTA, &args[0]);
1496 	else if (token == Opt_grpjquota)
1497 		return set_qf_name(sb, GRPQUOTA, &args[0]);
1498 	else if (token == Opt_offusrjquota)
1499 		return clear_qf_name(sb, USRQUOTA);
1500 	else if (token == Opt_offgrpjquota)
1501 		return clear_qf_name(sb, GRPQUOTA);
1502 #endif
1503 	if (args->from && match_int(args, &arg))
1504 		return -1;
1505 	switch (token) {
1506 	case Opt_noacl:
1507 	case Opt_nouser_xattr:
1508 		ext4_msg(sb, KERN_WARNING, deprecated_msg, opt, "3.5");
1509 		break;
1510 	case Opt_sb:
1511 		return 1;	/* handled by get_sb_block() */
1512 	case Opt_removed:
1513 		ext4_msg(sb, KERN_WARNING,
1514 			 "Ignoring removed %s option", opt);
1515 		return 1;
1516 	case Opt_resuid:
1517 		uid = make_kuid(current_user_ns(), arg);
1518 		if (!uid_valid(uid)) {
1519 			ext4_msg(sb, KERN_ERR, "Invalid uid value %d", arg);
1520 			return -1;
1521 		}
1522 		sbi->s_resuid = uid;
1523 		return 1;
1524 	case Opt_resgid:
1525 		gid = make_kgid(current_user_ns(), arg);
1526 		if (!gid_valid(gid)) {
1527 			ext4_msg(sb, KERN_ERR, "Invalid gid value %d", arg);
1528 			return -1;
1529 		}
1530 		sbi->s_resgid = gid;
1531 		return 1;
1532 	case Opt_abort:
1533 		sbi->s_mount_flags |= EXT4_MF_FS_ABORTED;
1534 		return 1;
1535 	case Opt_i_version:
1536 		sb->s_flags |= MS_I_VERSION;
1537 		return 1;
1538 	case Opt_journal_dev:
1539 		if (is_remount) {
1540 			ext4_msg(sb, KERN_ERR,
1541 				 "Cannot specify journal on remount");
1542 			return -1;
1543 		}
1544 		*journal_devnum = arg;
1545 		return 1;
1546 	case Opt_journal_ioprio:
1547 		if (arg < 0 || arg > 7)
1548 			return -1;
1549 		*journal_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, arg);
1550 		return 1;
1551 	}
1552 
1553 	for (m = ext4_mount_opts; m->token != Opt_err; m++) {
1554 		if (token != m->token)
1555 			continue;
1556 		if (args->from && (m->flags & MOPT_GTE0) && (arg < 0))
1557 			return -1;
1558 		if (m->flags & MOPT_EXPLICIT)
1559 			set_opt2(sb, EXPLICIT_DELALLOC);
1560 		if (m->flags & MOPT_CLEAR_ERR)
1561 			clear_opt(sb, ERRORS_MASK);
1562 		if (token == Opt_noquota && sb_any_quota_loaded(sb)) {
1563 			ext4_msg(sb, KERN_ERR, "Cannot change quota "
1564 				 "options when quota turned on");
1565 			return -1;
1566 		}
1567 
1568 		if (m->flags & MOPT_NOSUPPORT) {
1569 			ext4_msg(sb, KERN_ERR, "%s option not supported", opt);
1570 		} else if (token == Opt_commit) {
1571 			if (arg == 0)
1572 				arg = JBD2_DEFAULT_MAX_COMMIT_AGE;
1573 			sbi->s_commit_interval = HZ * arg;
1574 		} else if (token == Opt_max_batch_time) {
1575 			if (arg == 0)
1576 				arg = EXT4_DEF_MAX_BATCH_TIME;
1577 			sbi->s_max_batch_time = arg;
1578 		} else if (token == Opt_min_batch_time) {
1579 			sbi->s_min_batch_time = arg;
1580 		} else if (token == Opt_inode_readahead_blks) {
1581 			if (arg > (1 << 30))
1582 				return -1;
1583 			if (arg && !is_power_of_2(arg)) {
1584 				ext4_msg(sb, KERN_ERR,
1585 					 "EXT4-fs: inode_readahead_blks"
1586 					 " must be a power of 2");
1587 				return -1;
1588 			}
1589 			sbi->s_inode_readahead_blks = arg;
1590 		} else if (token == Opt_init_itable) {
1591 			set_opt(sb, INIT_INODE_TABLE);
1592 			if (!args->from)
1593 				arg = EXT4_DEF_LI_WAIT_MULT;
1594 			sbi->s_li_wait_mult = arg;
1595 		} else if (token == Opt_max_dir_size_kb) {
1596 			sbi->s_max_dir_size_kb = arg;
1597 		} else if (token == Opt_stripe) {
1598 			sbi->s_stripe = arg;
1599 		} else if (m->flags & MOPT_DATAJ) {
1600 			if (is_remount) {
1601 				if (!sbi->s_journal)
1602 					ext4_msg(sb, KERN_WARNING, "Remounting file system with no journal so ignoring journalled data option");
1603 				else if (test_opt(sb, DATA_FLAGS) !=
1604 					 m->mount_opt) {
1605 					ext4_msg(sb, KERN_ERR,
1606 					 "Cannot change data mode on remount");
1607 					return -1;
1608 				}
1609 			} else {
1610 				clear_opt(sb, DATA_FLAGS);
1611 				sbi->s_mount_opt |= m->mount_opt;
1612 			}
1613 #ifdef CONFIG_QUOTA
1614 		} else if (m->flags & MOPT_QFMT) {
1615 			if (sb_any_quota_loaded(sb) &&
1616 			    sbi->s_jquota_fmt != m->mount_opt) {
1617 				ext4_msg(sb, KERN_ERR, "Cannot "
1618 					 "change journaled quota options "
1619 					 "when quota turned on");
1620 				return -1;
1621 			}
1622 			sbi->s_jquota_fmt = m->mount_opt;
1623 #endif
1624 		} else {
1625 			if (!args->from)
1626 				arg = 1;
1627 			if (m->flags & MOPT_CLEAR)
1628 				arg = !arg;
1629 			else if (unlikely(!(m->flags & MOPT_SET))) {
1630 				ext4_msg(sb, KERN_WARNING,
1631 					 "buggy handling of option %s", opt);
1632 				WARN_ON(1);
1633 				return -1;
1634 			}
1635 			if (arg != 0)
1636 				sbi->s_mount_opt |= m->mount_opt;
1637 			else
1638 				sbi->s_mount_opt &= ~m->mount_opt;
1639 		}
1640 		return 1;
1641 	}
1642 	ext4_msg(sb, KERN_ERR, "Unrecognized mount option \"%s\" "
1643 		 "or missing value", opt);
1644 	return -1;
1645 }
1646 
1647 static int parse_options(char *options, struct super_block *sb,
1648 			 unsigned long *journal_devnum,
1649 			 unsigned int *journal_ioprio,
1650 			 int is_remount)
1651 {
1652 #ifdef CONFIG_QUOTA
1653 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1654 #endif
1655 	char *p;
1656 	substring_t args[MAX_OPT_ARGS];
1657 	int token;
1658 
1659 	if (!options)
1660 		return 1;
1661 
1662 	while ((p = strsep(&options, ",")) != NULL) {
1663 		if (!*p)
1664 			continue;
1665 		/*
1666 		 * Initialize args struct so we know whether arg was
1667 		 * found; some options take optional arguments.
1668 		 */
1669 		args[0].to = args[0].from = NULL;
1670 		token = match_token(p, tokens, args);
1671 		if (handle_mount_opt(sb, p, token, args, journal_devnum,
1672 				     journal_ioprio, is_remount) < 0)
1673 			return 0;
1674 	}
1675 #ifdef CONFIG_QUOTA
1676 	if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
1677 		if (test_opt(sb, USRQUOTA) && sbi->s_qf_names[USRQUOTA])
1678 			clear_opt(sb, USRQUOTA);
1679 
1680 		if (test_opt(sb, GRPQUOTA) && sbi->s_qf_names[GRPQUOTA])
1681 			clear_opt(sb, GRPQUOTA);
1682 
1683 		if (test_opt(sb, GRPQUOTA) || test_opt(sb, USRQUOTA)) {
1684 			ext4_msg(sb, KERN_ERR, "old and new quota "
1685 					"format mixing");
1686 			return 0;
1687 		}
1688 
1689 		if (!sbi->s_jquota_fmt) {
1690 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1691 					"not specified");
1692 			return 0;
1693 		}
1694 	} else {
1695 		if (sbi->s_jquota_fmt) {
1696 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1697 					"specified with no journaling "
1698 					"enabled");
1699 			return 0;
1700 		}
1701 	}
1702 #endif
1703 	return 1;
1704 }
1705 
1706 static inline void ext4_show_quota_options(struct seq_file *seq,
1707 					   struct super_block *sb)
1708 {
1709 #if defined(CONFIG_QUOTA)
1710 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1711 
1712 	if (sbi->s_jquota_fmt) {
1713 		char *fmtname = "";
1714 
1715 		switch (sbi->s_jquota_fmt) {
1716 		case QFMT_VFS_OLD:
1717 			fmtname = "vfsold";
1718 			break;
1719 		case QFMT_VFS_V0:
1720 			fmtname = "vfsv0";
1721 			break;
1722 		case QFMT_VFS_V1:
1723 			fmtname = "vfsv1";
1724 			break;
1725 		}
1726 		seq_printf(seq, ",jqfmt=%s", fmtname);
1727 	}
1728 
1729 	if (sbi->s_qf_names[USRQUOTA])
1730 		seq_printf(seq, ",usrjquota=%s", sbi->s_qf_names[USRQUOTA]);
1731 
1732 	if (sbi->s_qf_names[GRPQUOTA])
1733 		seq_printf(seq, ",grpjquota=%s", sbi->s_qf_names[GRPQUOTA]);
1734 
1735 	if (test_opt(sb, USRQUOTA))
1736 		seq_puts(seq, ",usrquota");
1737 
1738 	if (test_opt(sb, GRPQUOTA))
1739 		seq_puts(seq, ",grpquota");
1740 #endif
1741 }
1742 
1743 static const char *token2str(int token)
1744 {
1745 	const struct match_token *t;
1746 
1747 	for (t = tokens; t->token != Opt_err; t++)
1748 		if (t->token == token && !strchr(t->pattern, '='))
1749 			break;
1750 	return t->pattern;
1751 }
1752 
1753 /*
1754  * Show an option if
1755  *  - it's set to a non-default value OR
1756  *  - if the per-sb default is different from the global default
1757  */
1758 static int _ext4_show_options(struct seq_file *seq, struct super_block *sb,
1759 			      int nodefs)
1760 {
1761 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1762 	struct ext4_super_block *es = sbi->s_es;
1763 	int def_errors, def_mount_opt = nodefs ? 0 : sbi->s_def_mount_opt;
1764 	const struct mount_opts *m;
1765 	char sep = nodefs ? '\n' : ',';
1766 
1767 #define SEQ_OPTS_PUTS(str) seq_printf(seq, "%c" str, sep)
1768 #define SEQ_OPTS_PRINT(str, arg) seq_printf(seq, "%c" str, sep, arg)
1769 
1770 	if (sbi->s_sb_block != 1)
1771 		SEQ_OPTS_PRINT("sb=%llu", sbi->s_sb_block);
1772 
1773 	for (m = ext4_mount_opts; m->token != Opt_err; m++) {
1774 		int want_set = m->flags & MOPT_SET;
1775 		if (((m->flags & (MOPT_SET|MOPT_CLEAR)) == 0) ||
1776 		    (m->flags & MOPT_CLEAR_ERR))
1777 			continue;
1778 		if (!(m->mount_opt & (sbi->s_mount_opt ^ def_mount_opt)))
1779 			continue; /* skip if same as the default */
1780 		if ((want_set &&
1781 		     (sbi->s_mount_opt & m->mount_opt) != m->mount_opt) ||
1782 		    (!want_set && (sbi->s_mount_opt & m->mount_opt)))
1783 			continue; /* select Opt_noFoo vs Opt_Foo */
1784 		SEQ_OPTS_PRINT("%s", token2str(m->token));
1785 	}
1786 
1787 	if (nodefs || !uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT4_DEF_RESUID)) ||
1788 	    le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID)
1789 		SEQ_OPTS_PRINT("resuid=%u",
1790 				from_kuid_munged(&init_user_ns, sbi->s_resuid));
1791 	if (nodefs || !gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT4_DEF_RESGID)) ||
1792 	    le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID)
1793 		SEQ_OPTS_PRINT("resgid=%u",
1794 				from_kgid_munged(&init_user_ns, sbi->s_resgid));
1795 	def_errors = nodefs ? -1 : le16_to_cpu(es->s_errors);
1796 	if (test_opt(sb, ERRORS_RO) && def_errors != EXT4_ERRORS_RO)
1797 		SEQ_OPTS_PUTS("errors=remount-ro");
1798 	if (test_opt(sb, ERRORS_CONT) && def_errors != EXT4_ERRORS_CONTINUE)
1799 		SEQ_OPTS_PUTS("errors=continue");
1800 	if (test_opt(sb, ERRORS_PANIC) && def_errors != EXT4_ERRORS_PANIC)
1801 		SEQ_OPTS_PUTS("errors=panic");
1802 	if (nodefs || sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ)
1803 		SEQ_OPTS_PRINT("commit=%lu", sbi->s_commit_interval / HZ);
1804 	if (nodefs || sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME)
1805 		SEQ_OPTS_PRINT("min_batch_time=%u", sbi->s_min_batch_time);
1806 	if (nodefs || sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME)
1807 		SEQ_OPTS_PRINT("max_batch_time=%u", sbi->s_max_batch_time);
1808 	if (sb->s_flags & MS_I_VERSION)
1809 		SEQ_OPTS_PUTS("i_version");
1810 	if (nodefs || sbi->s_stripe)
1811 		SEQ_OPTS_PRINT("stripe=%lu", sbi->s_stripe);
1812 	if (EXT4_MOUNT_DATA_FLAGS & (sbi->s_mount_opt ^ def_mount_opt)) {
1813 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
1814 			SEQ_OPTS_PUTS("data=journal");
1815 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
1816 			SEQ_OPTS_PUTS("data=ordered");
1817 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
1818 			SEQ_OPTS_PUTS("data=writeback");
1819 	}
1820 	if (nodefs ||
1821 	    sbi->s_inode_readahead_blks != EXT4_DEF_INODE_READAHEAD_BLKS)
1822 		SEQ_OPTS_PRINT("inode_readahead_blks=%u",
1823 			       sbi->s_inode_readahead_blks);
1824 
1825 	if (nodefs || (test_opt(sb, INIT_INODE_TABLE) &&
1826 		       (sbi->s_li_wait_mult != EXT4_DEF_LI_WAIT_MULT)))
1827 		SEQ_OPTS_PRINT("init_itable=%u", sbi->s_li_wait_mult);
1828 	if (nodefs || sbi->s_max_dir_size_kb)
1829 		SEQ_OPTS_PRINT("max_dir_size_kb=%u", sbi->s_max_dir_size_kb);
1830 
1831 	ext4_show_quota_options(seq, sb);
1832 	return 0;
1833 }
1834 
1835 static int ext4_show_options(struct seq_file *seq, struct dentry *root)
1836 {
1837 	return _ext4_show_options(seq, root->d_sb, 0);
1838 }
1839 
1840 static int options_seq_show(struct seq_file *seq, void *offset)
1841 {
1842 	struct super_block *sb = seq->private;
1843 	int rc;
1844 
1845 	seq_puts(seq, (sb->s_flags & MS_RDONLY) ? "ro" : "rw");
1846 	rc = _ext4_show_options(seq, sb, 1);
1847 	seq_puts(seq, "\n");
1848 	return rc;
1849 }
1850 
1851 static int options_open_fs(struct inode *inode, struct file *file)
1852 {
1853 	return single_open(file, options_seq_show, PDE(inode)->data);
1854 }
1855 
1856 static const struct file_operations ext4_seq_options_fops = {
1857 	.owner = THIS_MODULE,
1858 	.open = options_open_fs,
1859 	.read = seq_read,
1860 	.llseek = seq_lseek,
1861 	.release = single_release,
1862 };
1863 
1864 static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
1865 			    int read_only)
1866 {
1867 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1868 	int res = 0;
1869 
1870 	if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
1871 		ext4_msg(sb, KERN_ERR, "revision level too high, "
1872 			 "forcing read-only mode");
1873 		res = MS_RDONLY;
1874 	}
1875 	if (read_only)
1876 		goto done;
1877 	if (!(sbi->s_mount_state & EXT4_VALID_FS))
1878 		ext4_msg(sb, KERN_WARNING, "warning: mounting unchecked fs, "
1879 			 "running e2fsck is recommended");
1880 	else if ((sbi->s_mount_state & EXT4_ERROR_FS))
1881 		ext4_msg(sb, KERN_WARNING,
1882 			 "warning: mounting fs with errors, "
1883 			 "running e2fsck is recommended");
1884 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) > 0 &&
1885 		 le16_to_cpu(es->s_mnt_count) >=
1886 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
1887 		ext4_msg(sb, KERN_WARNING,
1888 			 "warning: maximal mount count reached, "
1889 			 "running e2fsck is recommended");
1890 	else if (le32_to_cpu(es->s_checkinterval) &&
1891 		(le32_to_cpu(es->s_lastcheck) +
1892 			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
1893 		ext4_msg(sb, KERN_WARNING,
1894 			 "warning: checktime reached, "
1895 			 "running e2fsck is recommended");
1896 	if (!sbi->s_journal)
1897 		es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1898 	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
1899 		es->s_max_mnt_count = cpu_to_le16(EXT4_DFL_MAX_MNT_COUNT);
1900 	le16_add_cpu(&es->s_mnt_count, 1);
1901 	es->s_mtime = cpu_to_le32(get_seconds());
1902 	ext4_update_dynamic_rev(sb);
1903 	if (sbi->s_journal)
1904 		EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
1905 
1906 	ext4_commit_super(sb, 1);
1907 done:
1908 	if (test_opt(sb, DEBUG))
1909 		printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, "
1910 				"bpg=%lu, ipg=%lu, mo=%04x, mo2=%04x]\n",
1911 			sb->s_blocksize,
1912 			sbi->s_groups_count,
1913 			EXT4_BLOCKS_PER_GROUP(sb),
1914 			EXT4_INODES_PER_GROUP(sb),
1915 			sbi->s_mount_opt, sbi->s_mount_opt2);
1916 
1917 	cleancache_init_fs(sb);
1918 	return res;
1919 }
1920 
1921 int ext4_alloc_flex_bg_array(struct super_block *sb, ext4_group_t ngroup)
1922 {
1923 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1924 	struct flex_groups *new_groups;
1925 	int size;
1926 
1927 	if (!sbi->s_log_groups_per_flex)
1928 		return 0;
1929 
1930 	size = ext4_flex_group(sbi, ngroup - 1) + 1;
1931 	if (size <= sbi->s_flex_groups_allocated)
1932 		return 0;
1933 
1934 	size = roundup_pow_of_two(size * sizeof(struct flex_groups));
1935 	new_groups = ext4_kvzalloc(size, GFP_KERNEL);
1936 	if (!new_groups) {
1937 		ext4_msg(sb, KERN_ERR, "not enough memory for %d flex groups",
1938 			 size / (int) sizeof(struct flex_groups));
1939 		return -ENOMEM;
1940 	}
1941 
1942 	if (sbi->s_flex_groups) {
1943 		memcpy(new_groups, sbi->s_flex_groups,
1944 		       (sbi->s_flex_groups_allocated *
1945 			sizeof(struct flex_groups)));
1946 		ext4_kvfree(sbi->s_flex_groups);
1947 	}
1948 	sbi->s_flex_groups = new_groups;
1949 	sbi->s_flex_groups_allocated = size / sizeof(struct flex_groups);
1950 	return 0;
1951 }
1952 
1953 static int ext4_fill_flex_info(struct super_block *sb)
1954 {
1955 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1956 	struct ext4_group_desc *gdp = NULL;
1957 	ext4_group_t flex_group;
1958 	unsigned int groups_per_flex = 0;
1959 	int i, err;
1960 
1961 	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
1962 	if (sbi->s_log_groups_per_flex < 1 || sbi->s_log_groups_per_flex > 31) {
1963 		sbi->s_log_groups_per_flex = 0;
1964 		return 1;
1965 	}
1966 	groups_per_flex = 1 << sbi->s_log_groups_per_flex;
1967 
1968 	err = ext4_alloc_flex_bg_array(sb, sbi->s_groups_count);
1969 	if (err)
1970 		goto failed;
1971 
1972 	for (i = 0; i < sbi->s_groups_count; i++) {
1973 		gdp = ext4_get_group_desc(sb, i, NULL);
1974 
1975 		flex_group = ext4_flex_group(sbi, i);
1976 		atomic_add(ext4_free_inodes_count(sb, gdp),
1977 			   &sbi->s_flex_groups[flex_group].free_inodes);
1978 		atomic_add(ext4_free_group_clusters(sb, gdp),
1979 			   &sbi->s_flex_groups[flex_group].free_clusters);
1980 		atomic_add(ext4_used_dirs_count(sb, gdp),
1981 			   &sbi->s_flex_groups[flex_group].used_dirs);
1982 	}
1983 
1984 	return 1;
1985 failed:
1986 	return 0;
1987 }
1988 
1989 static __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
1990 				   struct ext4_group_desc *gdp)
1991 {
1992 	int offset;
1993 	__u16 crc = 0;
1994 	__le32 le_group = cpu_to_le32(block_group);
1995 
1996 	if ((sbi->s_es->s_feature_ro_compat &
1997 	     cpu_to_le32(EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))) {
1998 		/* Use new metadata_csum algorithm */
1999 		__u16 old_csum;
2000 		__u32 csum32;
2001 
2002 		old_csum = gdp->bg_checksum;
2003 		gdp->bg_checksum = 0;
2004 		csum32 = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&le_group,
2005 				     sizeof(le_group));
2006 		csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp,
2007 				     sbi->s_desc_size);
2008 		gdp->bg_checksum = old_csum;
2009 
2010 		crc = csum32 & 0xFFFF;
2011 		goto out;
2012 	}
2013 
2014 	/* old crc16 code */
2015 	offset = offsetof(struct ext4_group_desc, bg_checksum);
2016 
2017 	crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
2018 	crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
2019 	crc = crc16(crc, (__u8 *)gdp, offset);
2020 	offset += sizeof(gdp->bg_checksum); /* skip checksum */
2021 	/* for checksum of struct ext4_group_desc do the rest...*/
2022 	if ((sbi->s_es->s_feature_incompat &
2023 	     cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) &&
2024 	    offset < le16_to_cpu(sbi->s_es->s_desc_size))
2025 		crc = crc16(crc, (__u8 *)gdp + offset,
2026 			    le16_to_cpu(sbi->s_es->s_desc_size) -
2027 				offset);
2028 
2029 out:
2030 	return cpu_to_le16(crc);
2031 }
2032 
2033 int ext4_group_desc_csum_verify(struct super_block *sb, __u32 block_group,
2034 				struct ext4_group_desc *gdp)
2035 {
2036 	if (ext4_has_group_desc_csum(sb) &&
2037 	    (gdp->bg_checksum != ext4_group_desc_csum(EXT4_SB(sb),
2038 						      block_group, gdp)))
2039 		return 0;
2040 
2041 	return 1;
2042 }
2043 
2044 void ext4_group_desc_csum_set(struct super_block *sb, __u32 block_group,
2045 			      struct ext4_group_desc *gdp)
2046 {
2047 	if (!ext4_has_group_desc_csum(sb))
2048 		return;
2049 	gdp->bg_checksum = ext4_group_desc_csum(EXT4_SB(sb), block_group, gdp);
2050 }
2051 
2052 /* Called at mount-time, super-block is locked */
2053 static int ext4_check_descriptors(struct super_block *sb,
2054 				  ext4_group_t *first_not_zeroed)
2055 {
2056 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2057 	ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
2058 	ext4_fsblk_t last_block;
2059 	ext4_fsblk_t block_bitmap;
2060 	ext4_fsblk_t inode_bitmap;
2061 	ext4_fsblk_t inode_table;
2062 	int flexbg_flag = 0;
2063 	ext4_group_t i, grp = sbi->s_groups_count;
2064 
2065 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
2066 		flexbg_flag = 1;
2067 
2068 	ext4_debug("Checking group descriptors");
2069 
2070 	for (i = 0; i < sbi->s_groups_count; i++) {
2071 		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
2072 
2073 		if (i == sbi->s_groups_count - 1 || flexbg_flag)
2074 			last_block = ext4_blocks_count(sbi->s_es) - 1;
2075 		else
2076 			last_block = first_block +
2077 				(EXT4_BLOCKS_PER_GROUP(sb) - 1);
2078 
2079 		if ((grp == sbi->s_groups_count) &&
2080 		   !(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2081 			grp = i;
2082 
2083 		block_bitmap = ext4_block_bitmap(sb, gdp);
2084 		if (block_bitmap < first_block || block_bitmap > last_block) {
2085 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2086 			       "Block bitmap for group %u not in group "
2087 			       "(block %llu)!", i, block_bitmap);
2088 			return 0;
2089 		}
2090 		inode_bitmap = ext4_inode_bitmap(sb, gdp);
2091 		if (inode_bitmap < first_block || inode_bitmap > last_block) {
2092 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2093 			       "Inode bitmap for group %u not in group "
2094 			       "(block %llu)!", i, inode_bitmap);
2095 			return 0;
2096 		}
2097 		inode_table = ext4_inode_table(sb, gdp);
2098 		if (inode_table < first_block ||
2099 		    inode_table + sbi->s_itb_per_group - 1 > last_block) {
2100 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2101 			       "Inode table for group %u not in group "
2102 			       "(block %llu)!", i, inode_table);
2103 			return 0;
2104 		}
2105 		ext4_lock_group(sb, i);
2106 		if (!ext4_group_desc_csum_verify(sb, i, gdp)) {
2107 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2108 				 "Checksum for group %u failed (%u!=%u)",
2109 				 i, le16_to_cpu(ext4_group_desc_csum(sbi, i,
2110 				     gdp)), le16_to_cpu(gdp->bg_checksum));
2111 			if (!(sb->s_flags & MS_RDONLY)) {
2112 				ext4_unlock_group(sb, i);
2113 				return 0;
2114 			}
2115 		}
2116 		ext4_unlock_group(sb, i);
2117 		if (!flexbg_flag)
2118 			first_block += EXT4_BLOCKS_PER_GROUP(sb);
2119 	}
2120 	if (NULL != first_not_zeroed)
2121 		*first_not_zeroed = grp;
2122 
2123 	ext4_free_blocks_count_set(sbi->s_es,
2124 				   EXT4_C2B(sbi, ext4_count_free_clusters(sb)));
2125 	sbi->s_es->s_free_inodes_count =cpu_to_le32(ext4_count_free_inodes(sb));
2126 	return 1;
2127 }
2128 
2129 /* ext4_orphan_cleanup() walks a singly-linked list of inodes (starting at
2130  * the superblock) which were deleted from all directories, but held open by
2131  * a process at the time of a crash.  We walk the list and try to delete these
2132  * inodes at recovery time (only with a read-write filesystem).
2133  *
2134  * In order to keep the orphan inode chain consistent during traversal (in
2135  * case of crash during recovery), we link each inode into the superblock
2136  * orphan list_head and handle it the same way as an inode deletion during
2137  * normal operation (which journals the operations for us).
2138  *
2139  * We only do an iget() and an iput() on each inode, which is very safe if we
2140  * accidentally point at an in-use or already deleted inode.  The worst that
2141  * can happen in this case is that we get a "bit already cleared" message from
2142  * ext4_free_inode().  The only reason we would point at a wrong inode is if
2143  * e2fsck was run on this filesystem, and it must have already done the orphan
2144  * inode cleanup for us, so we can safely abort without any further action.
2145  */
2146 static void ext4_orphan_cleanup(struct super_block *sb,
2147 				struct ext4_super_block *es)
2148 {
2149 	unsigned int s_flags = sb->s_flags;
2150 	int nr_orphans = 0, nr_truncates = 0;
2151 #ifdef CONFIG_QUOTA
2152 	int i;
2153 #endif
2154 	if (!es->s_last_orphan) {
2155 		jbd_debug(4, "no orphan inodes to clean up\n");
2156 		return;
2157 	}
2158 
2159 	if (bdev_read_only(sb->s_bdev)) {
2160 		ext4_msg(sb, KERN_ERR, "write access "
2161 			"unavailable, skipping orphan cleanup");
2162 		return;
2163 	}
2164 
2165 	/* Check if feature set would not allow a r/w mount */
2166 	if (!ext4_feature_set_ok(sb, 0)) {
2167 		ext4_msg(sb, KERN_INFO, "Skipping orphan cleanup due to "
2168 			 "unknown ROCOMPAT features");
2169 		return;
2170 	}
2171 
2172 	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
2173 		/* don't clear list on RO mount w/ errors */
2174 		if (es->s_last_orphan && !(s_flags & MS_RDONLY)) {
2175 			jbd_debug(1, "Errors on filesystem, "
2176 				  "clearing orphan list.\n");
2177 			es->s_last_orphan = 0;
2178 		}
2179 		jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
2180 		return;
2181 	}
2182 
2183 	if (s_flags & MS_RDONLY) {
2184 		ext4_msg(sb, KERN_INFO, "orphan cleanup on readonly fs");
2185 		sb->s_flags &= ~MS_RDONLY;
2186 	}
2187 #ifdef CONFIG_QUOTA
2188 	/* Needed for iput() to work correctly and not trash data */
2189 	sb->s_flags |= MS_ACTIVE;
2190 	/* Turn on quotas so that they are updated correctly */
2191 	for (i = 0; i < MAXQUOTAS; i++) {
2192 		if (EXT4_SB(sb)->s_qf_names[i]) {
2193 			int ret = ext4_quota_on_mount(sb, i);
2194 			if (ret < 0)
2195 				ext4_msg(sb, KERN_ERR,
2196 					"Cannot turn on journaled "
2197 					"quota: error %d", ret);
2198 		}
2199 	}
2200 #endif
2201 
2202 	while (es->s_last_orphan) {
2203 		struct inode *inode;
2204 
2205 		inode = ext4_orphan_get(sb, le32_to_cpu(es->s_last_orphan));
2206 		if (IS_ERR(inode)) {
2207 			es->s_last_orphan = 0;
2208 			break;
2209 		}
2210 
2211 		list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
2212 		dquot_initialize(inode);
2213 		if (inode->i_nlink) {
2214 			ext4_msg(sb, KERN_DEBUG,
2215 				"%s: truncating inode %lu to %lld bytes",
2216 				__func__, inode->i_ino, inode->i_size);
2217 			jbd_debug(2, "truncating inode %lu to %lld bytes\n",
2218 				  inode->i_ino, inode->i_size);
2219 			ext4_truncate(inode);
2220 			nr_truncates++;
2221 		} else {
2222 			ext4_msg(sb, KERN_DEBUG,
2223 				"%s: deleting unreferenced inode %lu",
2224 				__func__, inode->i_ino);
2225 			jbd_debug(2, "deleting unreferenced inode %lu\n",
2226 				  inode->i_ino);
2227 			nr_orphans++;
2228 		}
2229 		iput(inode);  /* The delete magic happens here! */
2230 	}
2231 
2232 #define PLURAL(x) (x), ((x) == 1) ? "" : "s"
2233 
2234 	if (nr_orphans)
2235 		ext4_msg(sb, KERN_INFO, "%d orphan inode%s deleted",
2236 		       PLURAL(nr_orphans));
2237 	if (nr_truncates)
2238 		ext4_msg(sb, KERN_INFO, "%d truncate%s cleaned up",
2239 		       PLURAL(nr_truncates));
2240 #ifdef CONFIG_QUOTA
2241 	/* Turn quotas off */
2242 	for (i = 0; i < MAXQUOTAS; i++) {
2243 		if (sb_dqopt(sb)->files[i])
2244 			dquot_quota_off(sb, i);
2245 	}
2246 #endif
2247 	sb->s_flags = s_flags; /* Restore MS_RDONLY status */
2248 }
2249 
2250 /*
2251  * Maximal extent format file size.
2252  * Resulting logical blkno at s_maxbytes must fit in our on-disk
2253  * extent format containers, within a sector_t, and within i_blocks
2254  * in the vfs.  ext4 inode has 48 bits of i_block in fsblock units,
2255  * so that won't be a limiting factor.
2256  *
2257  * However there is other limiting factor. We do store extents in the form
2258  * of starting block and length, hence the resulting length of the extent
2259  * covering maximum file size must fit into on-disk format containers as
2260  * well. Given that length is always by 1 unit bigger than max unit (because
2261  * we count 0 as well) we have to lower the s_maxbytes by one fs block.
2262  *
2263  * Note, this does *not* consider any metadata overhead for vfs i_blocks.
2264  */
2265 static loff_t ext4_max_size(int blkbits, int has_huge_files)
2266 {
2267 	loff_t res;
2268 	loff_t upper_limit = MAX_LFS_FILESIZE;
2269 
2270 	/* small i_blocks in vfs inode? */
2271 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2272 		/*
2273 		 * CONFIG_LBDAF is not enabled implies the inode
2274 		 * i_block represent total blocks in 512 bytes
2275 		 * 32 == size of vfs inode i_blocks * 8
2276 		 */
2277 		upper_limit = (1LL << 32) - 1;
2278 
2279 		/* total blocks in file system block size */
2280 		upper_limit >>= (blkbits - 9);
2281 		upper_limit <<= blkbits;
2282 	}
2283 
2284 	/*
2285 	 * 32-bit extent-start container, ee_block. We lower the maxbytes
2286 	 * by one fs block, so ee_len can cover the extent of maximum file
2287 	 * size
2288 	 */
2289 	res = (1LL << 32) - 1;
2290 	res <<= blkbits;
2291 
2292 	/* Sanity check against vm- & vfs- imposed limits */
2293 	if (res > upper_limit)
2294 		res = upper_limit;
2295 
2296 	return res;
2297 }
2298 
2299 /*
2300  * Maximal bitmap file size.  There is a direct, and {,double-,triple-}indirect
2301  * block limit, and also a limit of (2^48 - 1) 512-byte sectors in i_blocks.
2302  * We need to be 1 filesystem block less than the 2^48 sector limit.
2303  */
2304 static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
2305 {
2306 	loff_t res = EXT4_NDIR_BLOCKS;
2307 	int meta_blocks;
2308 	loff_t upper_limit;
2309 	/* This is calculated to be the largest file size for a dense, block
2310 	 * mapped file such that the file's total number of 512-byte sectors,
2311 	 * including data and all indirect blocks, does not exceed (2^48 - 1).
2312 	 *
2313 	 * __u32 i_blocks_lo and _u16 i_blocks_high represent the total
2314 	 * number of 512-byte sectors of the file.
2315 	 */
2316 
2317 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2318 		/*
2319 		 * !has_huge_files or CONFIG_LBDAF not enabled implies that
2320 		 * the inode i_block field represents total file blocks in
2321 		 * 2^32 512-byte sectors == size of vfs inode i_blocks * 8
2322 		 */
2323 		upper_limit = (1LL << 32) - 1;
2324 
2325 		/* total blocks in file system block size */
2326 		upper_limit >>= (bits - 9);
2327 
2328 	} else {
2329 		/*
2330 		 * We use 48 bit ext4_inode i_blocks
2331 		 * With EXT4_HUGE_FILE_FL set the i_blocks
2332 		 * represent total number of blocks in
2333 		 * file system block size
2334 		 */
2335 		upper_limit = (1LL << 48) - 1;
2336 
2337 	}
2338 
2339 	/* indirect blocks */
2340 	meta_blocks = 1;
2341 	/* double indirect blocks */
2342 	meta_blocks += 1 + (1LL << (bits-2));
2343 	/* tripple indirect blocks */
2344 	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
2345 
2346 	upper_limit -= meta_blocks;
2347 	upper_limit <<= bits;
2348 
2349 	res += 1LL << (bits-2);
2350 	res += 1LL << (2*(bits-2));
2351 	res += 1LL << (3*(bits-2));
2352 	res <<= bits;
2353 	if (res > upper_limit)
2354 		res = upper_limit;
2355 
2356 	if (res > MAX_LFS_FILESIZE)
2357 		res = MAX_LFS_FILESIZE;
2358 
2359 	return res;
2360 }
2361 
2362 static ext4_fsblk_t descriptor_loc(struct super_block *sb,
2363 				   ext4_fsblk_t logical_sb_block, int nr)
2364 {
2365 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2366 	ext4_group_t bg, first_meta_bg;
2367 	int has_super = 0;
2368 
2369 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
2370 
2371 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
2372 	    nr < first_meta_bg)
2373 		return logical_sb_block + nr + 1;
2374 	bg = sbi->s_desc_per_block * nr;
2375 	if (ext4_bg_has_super(sb, bg))
2376 		has_super = 1;
2377 
2378 	return (has_super + ext4_group_first_block_no(sb, bg));
2379 }
2380 
2381 /**
2382  * ext4_get_stripe_size: Get the stripe size.
2383  * @sbi: In memory super block info
2384  *
2385  * If we have specified it via mount option, then
2386  * use the mount option value. If the value specified at mount time is
2387  * greater than the blocks per group use the super block value.
2388  * If the super block value is greater than blocks per group return 0.
2389  * Allocator needs it be less than blocks per group.
2390  *
2391  */
2392 static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi)
2393 {
2394 	unsigned long stride = le16_to_cpu(sbi->s_es->s_raid_stride);
2395 	unsigned long stripe_width =
2396 			le32_to_cpu(sbi->s_es->s_raid_stripe_width);
2397 	int ret;
2398 
2399 	if (sbi->s_stripe && sbi->s_stripe <= sbi->s_blocks_per_group)
2400 		ret = sbi->s_stripe;
2401 	else if (stripe_width <= sbi->s_blocks_per_group)
2402 		ret = stripe_width;
2403 	else if (stride <= sbi->s_blocks_per_group)
2404 		ret = stride;
2405 	else
2406 		ret = 0;
2407 
2408 	/*
2409 	 * If the stripe width is 1, this makes no sense and
2410 	 * we set it to 0 to turn off stripe handling code.
2411 	 */
2412 	if (ret <= 1)
2413 		ret = 0;
2414 
2415 	return ret;
2416 }
2417 
2418 /* sysfs supprt */
2419 
2420 struct ext4_attr {
2421 	struct attribute attr;
2422 	ssize_t (*show)(struct ext4_attr *, struct ext4_sb_info *, char *);
2423 	ssize_t (*store)(struct ext4_attr *, struct ext4_sb_info *,
2424 			 const char *, size_t);
2425 	int offset;
2426 };
2427 
2428 static int parse_strtoul(const char *buf,
2429 		unsigned long max, unsigned long *value)
2430 {
2431 	char *endp;
2432 
2433 	*value = simple_strtoul(skip_spaces(buf), &endp, 0);
2434 	endp = skip_spaces(endp);
2435 	if (*endp || *value > max)
2436 		return -EINVAL;
2437 
2438 	return 0;
2439 }
2440 
2441 static ssize_t delayed_allocation_blocks_show(struct ext4_attr *a,
2442 					      struct ext4_sb_info *sbi,
2443 					      char *buf)
2444 {
2445 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2446 		(s64) EXT4_C2B(sbi,
2447 			percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
2448 }
2449 
2450 static ssize_t session_write_kbytes_show(struct ext4_attr *a,
2451 					 struct ext4_sb_info *sbi, char *buf)
2452 {
2453 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
2454 
2455 	if (!sb->s_bdev->bd_part)
2456 		return snprintf(buf, PAGE_SIZE, "0\n");
2457 	return snprintf(buf, PAGE_SIZE, "%lu\n",
2458 			(part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
2459 			 sbi->s_sectors_written_start) >> 1);
2460 }
2461 
2462 static ssize_t lifetime_write_kbytes_show(struct ext4_attr *a,
2463 					  struct ext4_sb_info *sbi, char *buf)
2464 {
2465 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
2466 
2467 	if (!sb->s_bdev->bd_part)
2468 		return snprintf(buf, PAGE_SIZE, "0\n");
2469 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2470 			(unsigned long long)(sbi->s_kbytes_written +
2471 			((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
2472 			  EXT4_SB(sb)->s_sectors_written_start) >> 1)));
2473 }
2474 
2475 static ssize_t inode_readahead_blks_store(struct ext4_attr *a,
2476 					  struct ext4_sb_info *sbi,
2477 					  const char *buf, size_t count)
2478 {
2479 	unsigned long t;
2480 
2481 	if (parse_strtoul(buf, 0x40000000, &t))
2482 		return -EINVAL;
2483 
2484 	if (t && !is_power_of_2(t))
2485 		return -EINVAL;
2486 
2487 	sbi->s_inode_readahead_blks = t;
2488 	return count;
2489 }
2490 
2491 static ssize_t sbi_ui_show(struct ext4_attr *a,
2492 			   struct ext4_sb_info *sbi, char *buf)
2493 {
2494 	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
2495 
2496 	return snprintf(buf, PAGE_SIZE, "%u\n", *ui);
2497 }
2498 
2499 static ssize_t sbi_ui_store(struct ext4_attr *a,
2500 			    struct ext4_sb_info *sbi,
2501 			    const char *buf, size_t count)
2502 {
2503 	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
2504 	unsigned long t;
2505 
2506 	if (parse_strtoul(buf, 0xffffffff, &t))
2507 		return -EINVAL;
2508 	*ui = t;
2509 	return count;
2510 }
2511 
2512 static ssize_t trigger_test_error(struct ext4_attr *a,
2513 				  struct ext4_sb_info *sbi,
2514 				  const char *buf, size_t count)
2515 {
2516 	int len = count;
2517 
2518 	if (!capable(CAP_SYS_ADMIN))
2519 		return -EPERM;
2520 
2521 	if (len && buf[len-1] == '\n')
2522 		len--;
2523 
2524 	if (len)
2525 		ext4_error(sbi->s_sb, "%.*s", len, buf);
2526 	return count;
2527 }
2528 
2529 #define EXT4_ATTR_OFFSET(_name,_mode,_show,_store,_elname) \
2530 static struct ext4_attr ext4_attr_##_name = {			\
2531 	.attr = {.name = __stringify(_name), .mode = _mode },	\
2532 	.show	= _show,					\
2533 	.store	= _store,					\
2534 	.offset = offsetof(struct ext4_sb_info, _elname),	\
2535 }
2536 #define EXT4_ATTR(name, mode, show, store) \
2537 static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store)
2538 
2539 #define EXT4_INFO_ATTR(name) EXT4_ATTR(name, 0444, NULL, NULL)
2540 #define EXT4_RO_ATTR(name) EXT4_ATTR(name, 0444, name##_show, NULL)
2541 #define EXT4_RW_ATTR(name) EXT4_ATTR(name, 0644, name##_show, name##_store)
2542 #define EXT4_RW_ATTR_SBI_UI(name, elname)	\
2543 	EXT4_ATTR_OFFSET(name, 0644, sbi_ui_show, sbi_ui_store, elname)
2544 #define ATTR_LIST(name) &ext4_attr_##name.attr
2545 
2546 EXT4_RO_ATTR(delayed_allocation_blocks);
2547 EXT4_RO_ATTR(session_write_kbytes);
2548 EXT4_RO_ATTR(lifetime_write_kbytes);
2549 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, sbi_ui_show,
2550 		 inode_readahead_blks_store, s_inode_readahead_blks);
2551 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
2552 EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
2553 EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
2554 EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
2555 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
2556 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
2557 EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
2558 EXT4_RW_ATTR_SBI_UI(max_writeback_mb_bump, s_max_writeback_mb_bump);
2559 EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
2560 EXT4_ATTR(trigger_fs_error, 0200, NULL, trigger_test_error);
2561 
2562 static struct attribute *ext4_attrs[] = {
2563 	ATTR_LIST(delayed_allocation_blocks),
2564 	ATTR_LIST(session_write_kbytes),
2565 	ATTR_LIST(lifetime_write_kbytes),
2566 	ATTR_LIST(inode_readahead_blks),
2567 	ATTR_LIST(inode_goal),
2568 	ATTR_LIST(mb_stats),
2569 	ATTR_LIST(mb_max_to_scan),
2570 	ATTR_LIST(mb_min_to_scan),
2571 	ATTR_LIST(mb_order2_req),
2572 	ATTR_LIST(mb_stream_req),
2573 	ATTR_LIST(mb_group_prealloc),
2574 	ATTR_LIST(max_writeback_mb_bump),
2575 	ATTR_LIST(extent_max_zeroout_kb),
2576 	ATTR_LIST(trigger_fs_error),
2577 	NULL,
2578 };
2579 
2580 /* Features this copy of ext4 supports */
2581 EXT4_INFO_ATTR(lazy_itable_init);
2582 EXT4_INFO_ATTR(batched_discard);
2583 EXT4_INFO_ATTR(meta_bg_resize);
2584 
2585 static struct attribute *ext4_feat_attrs[] = {
2586 	ATTR_LIST(lazy_itable_init),
2587 	ATTR_LIST(batched_discard),
2588 	ATTR_LIST(meta_bg_resize),
2589 	NULL,
2590 };
2591 
2592 static ssize_t ext4_attr_show(struct kobject *kobj,
2593 			      struct attribute *attr, char *buf)
2594 {
2595 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2596 						s_kobj);
2597 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
2598 
2599 	return a->show ? a->show(a, sbi, buf) : 0;
2600 }
2601 
2602 static ssize_t ext4_attr_store(struct kobject *kobj,
2603 			       struct attribute *attr,
2604 			       const char *buf, size_t len)
2605 {
2606 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2607 						s_kobj);
2608 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
2609 
2610 	return a->store ? a->store(a, sbi, buf, len) : 0;
2611 }
2612 
2613 static void ext4_sb_release(struct kobject *kobj)
2614 {
2615 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2616 						s_kobj);
2617 	complete(&sbi->s_kobj_unregister);
2618 }
2619 
2620 static const struct sysfs_ops ext4_attr_ops = {
2621 	.show	= ext4_attr_show,
2622 	.store	= ext4_attr_store,
2623 };
2624 
2625 static struct kobj_type ext4_ktype = {
2626 	.default_attrs	= ext4_attrs,
2627 	.sysfs_ops	= &ext4_attr_ops,
2628 	.release	= ext4_sb_release,
2629 };
2630 
2631 static void ext4_feat_release(struct kobject *kobj)
2632 {
2633 	complete(&ext4_feat->f_kobj_unregister);
2634 }
2635 
2636 static struct kobj_type ext4_feat_ktype = {
2637 	.default_attrs	= ext4_feat_attrs,
2638 	.sysfs_ops	= &ext4_attr_ops,
2639 	.release	= ext4_feat_release,
2640 };
2641 
2642 /*
2643  * Check whether this filesystem can be mounted based on
2644  * the features present and the RDONLY/RDWR mount requested.
2645  * Returns 1 if this filesystem can be mounted as requested,
2646  * 0 if it cannot be.
2647  */
2648 static int ext4_feature_set_ok(struct super_block *sb, int readonly)
2649 {
2650 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT4_FEATURE_INCOMPAT_SUPP)) {
2651 		ext4_msg(sb, KERN_ERR,
2652 			"Couldn't mount because of "
2653 			"unsupported optional features (%x)",
2654 			(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_incompat) &
2655 			~EXT4_FEATURE_INCOMPAT_SUPP));
2656 		return 0;
2657 	}
2658 
2659 	if (readonly)
2660 		return 1;
2661 
2662 	/* Check that feature set is OK for a read-write mount */
2663 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT4_FEATURE_RO_COMPAT_SUPP)) {
2664 		ext4_msg(sb, KERN_ERR, "couldn't mount RDWR because of "
2665 			 "unsupported optional features (%x)",
2666 			 (le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_ro_compat) &
2667 				~EXT4_FEATURE_RO_COMPAT_SUPP));
2668 		return 0;
2669 	}
2670 	/*
2671 	 * Large file size enabled file system can only be mounted
2672 	 * read-write on 32-bit systems if kernel is built with CONFIG_LBDAF
2673 	 */
2674 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
2675 		if (sizeof(blkcnt_t) < sizeof(u64)) {
2676 			ext4_msg(sb, KERN_ERR, "Filesystem with huge files "
2677 				 "cannot be mounted RDWR without "
2678 				 "CONFIG_LBDAF");
2679 			return 0;
2680 		}
2681 	}
2682 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_BIGALLOC) &&
2683 	    !EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
2684 		ext4_msg(sb, KERN_ERR,
2685 			 "Can't support bigalloc feature without "
2686 			 "extents feature\n");
2687 		return 0;
2688 	}
2689 
2690 #ifndef CONFIG_QUOTA
2691 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA) &&
2692 	    !readonly) {
2693 		ext4_msg(sb, KERN_ERR,
2694 			 "Filesystem with quota feature cannot be mounted RDWR "
2695 			 "without CONFIG_QUOTA");
2696 		return 0;
2697 	}
2698 #endif  /* CONFIG_QUOTA */
2699 	return 1;
2700 }
2701 
2702 /*
2703  * This function is called once a day if we have errors logged
2704  * on the file system
2705  */
2706 static void print_daily_error_info(unsigned long arg)
2707 {
2708 	struct super_block *sb = (struct super_block *) arg;
2709 	struct ext4_sb_info *sbi;
2710 	struct ext4_super_block *es;
2711 
2712 	sbi = EXT4_SB(sb);
2713 	es = sbi->s_es;
2714 
2715 	if (es->s_error_count)
2716 		ext4_msg(sb, KERN_NOTICE, "error count: %u",
2717 			 le32_to_cpu(es->s_error_count));
2718 	if (es->s_first_error_time) {
2719 		printk(KERN_NOTICE "EXT4-fs (%s): initial error at %u: %.*s:%d",
2720 		       sb->s_id, le32_to_cpu(es->s_first_error_time),
2721 		       (int) sizeof(es->s_first_error_func),
2722 		       es->s_first_error_func,
2723 		       le32_to_cpu(es->s_first_error_line));
2724 		if (es->s_first_error_ino)
2725 			printk(": inode %u",
2726 			       le32_to_cpu(es->s_first_error_ino));
2727 		if (es->s_first_error_block)
2728 			printk(": block %llu", (unsigned long long)
2729 			       le64_to_cpu(es->s_first_error_block));
2730 		printk("\n");
2731 	}
2732 	if (es->s_last_error_time) {
2733 		printk(KERN_NOTICE "EXT4-fs (%s): last error at %u: %.*s:%d",
2734 		       sb->s_id, le32_to_cpu(es->s_last_error_time),
2735 		       (int) sizeof(es->s_last_error_func),
2736 		       es->s_last_error_func,
2737 		       le32_to_cpu(es->s_last_error_line));
2738 		if (es->s_last_error_ino)
2739 			printk(": inode %u",
2740 			       le32_to_cpu(es->s_last_error_ino));
2741 		if (es->s_last_error_block)
2742 			printk(": block %llu", (unsigned long long)
2743 			       le64_to_cpu(es->s_last_error_block));
2744 		printk("\n");
2745 	}
2746 	mod_timer(&sbi->s_err_report, jiffies + 24*60*60*HZ);  /* Once a day */
2747 }
2748 
2749 /* Find next suitable group and run ext4_init_inode_table */
2750 static int ext4_run_li_request(struct ext4_li_request *elr)
2751 {
2752 	struct ext4_group_desc *gdp = NULL;
2753 	ext4_group_t group, ngroups;
2754 	struct super_block *sb;
2755 	unsigned long timeout = 0;
2756 	int ret = 0;
2757 
2758 	sb = elr->lr_super;
2759 	ngroups = EXT4_SB(sb)->s_groups_count;
2760 
2761 	sb_start_write(sb);
2762 	for (group = elr->lr_next_group; group < ngroups; group++) {
2763 		gdp = ext4_get_group_desc(sb, group, NULL);
2764 		if (!gdp) {
2765 			ret = 1;
2766 			break;
2767 		}
2768 
2769 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2770 			break;
2771 	}
2772 
2773 	if (group == ngroups)
2774 		ret = 1;
2775 
2776 	if (!ret) {
2777 		timeout = jiffies;
2778 		ret = ext4_init_inode_table(sb, group,
2779 					    elr->lr_timeout ? 0 : 1);
2780 		if (elr->lr_timeout == 0) {
2781 			timeout = (jiffies - timeout) *
2782 				  elr->lr_sbi->s_li_wait_mult;
2783 			elr->lr_timeout = timeout;
2784 		}
2785 		elr->lr_next_sched = jiffies + elr->lr_timeout;
2786 		elr->lr_next_group = group + 1;
2787 	}
2788 	sb_end_write(sb);
2789 
2790 	return ret;
2791 }
2792 
2793 /*
2794  * Remove lr_request from the list_request and free the
2795  * request structure. Should be called with li_list_mtx held
2796  */
2797 static void ext4_remove_li_request(struct ext4_li_request *elr)
2798 {
2799 	struct ext4_sb_info *sbi;
2800 
2801 	if (!elr)
2802 		return;
2803 
2804 	sbi = elr->lr_sbi;
2805 
2806 	list_del(&elr->lr_request);
2807 	sbi->s_li_request = NULL;
2808 	kfree(elr);
2809 }
2810 
2811 static void ext4_unregister_li_request(struct super_block *sb)
2812 {
2813 	mutex_lock(&ext4_li_mtx);
2814 	if (!ext4_li_info) {
2815 		mutex_unlock(&ext4_li_mtx);
2816 		return;
2817 	}
2818 
2819 	mutex_lock(&ext4_li_info->li_list_mtx);
2820 	ext4_remove_li_request(EXT4_SB(sb)->s_li_request);
2821 	mutex_unlock(&ext4_li_info->li_list_mtx);
2822 	mutex_unlock(&ext4_li_mtx);
2823 }
2824 
2825 static struct task_struct *ext4_lazyinit_task;
2826 
2827 /*
2828  * This is the function where ext4lazyinit thread lives. It walks
2829  * through the request list searching for next scheduled filesystem.
2830  * When such a fs is found, run the lazy initialization request
2831  * (ext4_rn_li_request) and keep track of the time spend in this
2832  * function. Based on that time we compute next schedule time of
2833  * the request. When walking through the list is complete, compute
2834  * next waking time and put itself into sleep.
2835  */
2836 static int ext4_lazyinit_thread(void *arg)
2837 {
2838 	struct ext4_lazy_init *eli = (struct ext4_lazy_init *)arg;
2839 	struct list_head *pos, *n;
2840 	struct ext4_li_request *elr;
2841 	unsigned long next_wakeup, cur;
2842 
2843 	BUG_ON(NULL == eli);
2844 
2845 cont_thread:
2846 	while (true) {
2847 		next_wakeup = MAX_JIFFY_OFFSET;
2848 
2849 		mutex_lock(&eli->li_list_mtx);
2850 		if (list_empty(&eli->li_request_list)) {
2851 			mutex_unlock(&eli->li_list_mtx);
2852 			goto exit_thread;
2853 		}
2854 
2855 		list_for_each_safe(pos, n, &eli->li_request_list) {
2856 			elr = list_entry(pos, struct ext4_li_request,
2857 					 lr_request);
2858 
2859 			if (time_after_eq(jiffies, elr->lr_next_sched)) {
2860 				if (ext4_run_li_request(elr) != 0) {
2861 					/* error, remove the lazy_init job */
2862 					ext4_remove_li_request(elr);
2863 					continue;
2864 				}
2865 			}
2866 
2867 			if (time_before(elr->lr_next_sched, next_wakeup))
2868 				next_wakeup = elr->lr_next_sched;
2869 		}
2870 		mutex_unlock(&eli->li_list_mtx);
2871 
2872 		try_to_freeze();
2873 
2874 		cur = jiffies;
2875 		if ((time_after_eq(cur, next_wakeup)) ||
2876 		    (MAX_JIFFY_OFFSET == next_wakeup)) {
2877 			cond_resched();
2878 			continue;
2879 		}
2880 
2881 		schedule_timeout_interruptible(next_wakeup - cur);
2882 
2883 		if (kthread_should_stop()) {
2884 			ext4_clear_request_list();
2885 			goto exit_thread;
2886 		}
2887 	}
2888 
2889 exit_thread:
2890 	/*
2891 	 * It looks like the request list is empty, but we need
2892 	 * to check it under the li_list_mtx lock, to prevent any
2893 	 * additions into it, and of course we should lock ext4_li_mtx
2894 	 * to atomically free the list and ext4_li_info, because at
2895 	 * this point another ext4 filesystem could be registering
2896 	 * new one.
2897 	 */
2898 	mutex_lock(&ext4_li_mtx);
2899 	mutex_lock(&eli->li_list_mtx);
2900 	if (!list_empty(&eli->li_request_list)) {
2901 		mutex_unlock(&eli->li_list_mtx);
2902 		mutex_unlock(&ext4_li_mtx);
2903 		goto cont_thread;
2904 	}
2905 	mutex_unlock(&eli->li_list_mtx);
2906 	kfree(ext4_li_info);
2907 	ext4_li_info = NULL;
2908 	mutex_unlock(&ext4_li_mtx);
2909 
2910 	return 0;
2911 }
2912 
2913 static void ext4_clear_request_list(void)
2914 {
2915 	struct list_head *pos, *n;
2916 	struct ext4_li_request *elr;
2917 
2918 	mutex_lock(&ext4_li_info->li_list_mtx);
2919 	list_for_each_safe(pos, n, &ext4_li_info->li_request_list) {
2920 		elr = list_entry(pos, struct ext4_li_request,
2921 				 lr_request);
2922 		ext4_remove_li_request(elr);
2923 	}
2924 	mutex_unlock(&ext4_li_info->li_list_mtx);
2925 }
2926 
2927 static int ext4_run_lazyinit_thread(void)
2928 {
2929 	ext4_lazyinit_task = kthread_run(ext4_lazyinit_thread,
2930 					 ext4_li_info, "ext4lazyinit");
2931 	if (IS_ERR(ext4_lazyinit_task)) {
2932 		int err = PTR_ERR(ext4_lazyinit_task);
2933 		ext4_clear_request_list();
2934 		kfree(ext4_li_info);
2935 		ext4_li_info = NULL;
2936 		printk(KERN_CRIT "EXT4-fs: error %d creating inode table "
2937 				 "initialization thread\n",
2938 				 err);
2939 		return err;
2940 	}
2941 	ext4_li_info->li_state |= EXT4_LAZYINIT_RUNNING;
2942 	return 0;
2943 }
2944 
2945 /*
2946  * Check whether it make sense to run itable init. thread or not.
2947  * If there is at least one uninitialized inode table, return
2948  * corresponding group number, else the loop goes through all
2949  * groups and return total number of groups.
2950  */
2951 static ext4_group_t ext4_has_uninit_itable(struct super_block *sb)
2952 {
2953 	ext4_group_t group, ngroups = EXT4_SB(sb)->s_groups_count;
2954 	struct ext4_group_desc *gdp = NULL;
2955 
2956 	for (group = 0; group < ngroups; group++) {
2957 		gdp = ext4_get_group_desc(sb, group, NULL);
2958 		if (!gdp)
2959 			continue;
2960 
2961 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2962 			break;
2963 	}
2964 
2965 	return group;
2966 }
2967 
2968 static int ext4_li_info_new(void)
2969 {
2970 	struct ext4_lazy_init *eli = NULL;
2971 
2972 	eli = kzalloc(sizeof(*eli), GFP_KERNEL);
2973 	if (!eli)
2974 		return -ENOMEM;
2975 
2976 	INIT_LIST_HEAD(&eli->li_request_list);
2977 	mutex_init(&eli->li_list_mtx);
2978 
2979 	eli->li_state |= EXT4_LAZYINIT_QUIT;
2980 
2981 	ext4_li_info = eli;
2982 
2983 	return 0;
2984 }
2985 
2986 static struct ext4_li_request *ext4_li_request_new(struct super_block *sb,
2987 					    ext4_group_t start)
2988 {
2989 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2990 	struct ext4_li_request *elr;
2991 	unsigned long rnd;
2992 
2993 	elr = kzalloc(sizeof(*elr), GFP_KERNEL);
2994 	if (!elr)
2995 		return NULL;
2996 
2997 	elr->lr_super = sb;
2998 	elr->lr_sbi = sbi;
2999 	elr->lr_next_group = start;
3000 
3001 	/*
3002 	 * Randomize first schedule time of the request to
3003 	 * spread the inode table initialization requests
3004 	 * better.
3005 	 */
3006 	get_random_bytes(&rnd, sizeof(rnd));
3007 	elr->lr_next_sched = jiffies + (unsigned long)rnd %
3008 			     (EXT4_DEF_LI_MAX_START_DELAY * HZ);
3009 
3010 	return elr;
3011 }
3012 
3013 static int ext4_register_li_request(struct super_block *sb,
3014 				    ext4_group_t first_not_zeroed)
3015 {
3016 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3017 	struct ext4_li_request *elr;
3018 	ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
3019 	int ret = 0;
3020 
3021 	if (sbi->s_li_request != NULL) {
3022 		/*
3023 		 * Reset timeout so it can be computed again, because
3024 		 * s_li_wait_mult might have changed.
3025 		 */
3026 		sbi->s_li_request->lr_timeout = 0;
3027 		return 0;
3028 	}
3029 
3030 	if (first_not_zeroed == ngroups ||
3031 	    (sb->s_flags & MS_RDONLY) ||
3032 	    !test_opt(sb, INIT_INODE_TABLE))
3033 		return 0;
3034 
3035 	elr = ext4_li_request_new(sb, first_not_zeroed);
3036 	if (!elr)
3037 		return -ENOMEM;
3038 
3039 	mutex_lock(&ext4_li_mtx);
3040 
3041 	if (NULL == ext4_li_info) {
3042 		ret = ext4_li_info_new();
3043 		if (ret)
3044 			goto out;
3045 	}
3046 
3047 	mutex_lock(&ext4_li_info->li_list_mtx);
3048 	list_add(&elr->lr_request, &ext4_li_info->li_request_list);
3049 	mutex_unlock(&ext4_li_info->li_list_mtx);
3050 
3051 	sbi->s_li_request = elr;
3052 	/*
3053 	 * set elr to NULL here since it has been inserted to
3054 	 * the request_list and the removal and free of it is
3055 	 * handled by ext4_clear_request_list from now on.
3056 	 */
3057 	elr = NULL;
3058 
3059 	if (!(ext4_li_info->li_state & EXT4_LAZYINIT_RUNNING)) {
3060 		ret = ext4_run_lazyinit_thread();
3061 		if (ret)
3062 			goto out;
3063 	}
3064 out:
3065 	mutex_unlock(&ext4_li_mtx);
3066 	if (ret)
3067 		kfree(elr);
3068 	return ret;
3069 }
3070 
3071 /*
3072  * We do not need to lock anything since this is called on
3073  * module unload.
3074  */
3075 static void ext4_destroy_lazyinit_thread(void)
3076 {
3077 	/*
3078 	 * If thread exited earlier
3079 	 * there's nothing to be done.
3080 	 */
3081 	if (!ext4_li_info || !ext4_lazyinit_task)
3082 		return;
3083 
3084 	kthread_stop(ext4_lazyinit_task);
3085 }
3086 
3087 static int set_journal_csum_feature_set(struct super_block *sb)
3088 {
3089 	int ret = 1;
3090 	int compat, incompat;
3091 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3092 
3093 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3094 				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
3095 		/* journal checksum v2 */
3096 		compat = 0;
3097 		incompat = JBD2_FEATURE_INCOMPAT_CSUM_V2;
3098 	} else {
3099 		/* journal checksum v1 */
3100 		compat = JBD2_FEATURE_COMPAT_CHECKSUM;
3101 		incompat = 0;
3102 	}
3103 
3104 	if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
3105 		ret = jbd2_journal_set_features(sbi->s_journal,
3106 				compat, 0,
3107 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT |
3108 				incompat);
3109 	} else if (test_opt(sb, JOURNAL_CHECKSUM)) {
3110 		ret = jbd2_journal_set_features(sbi->s_journal,
3111 				compat, 0,
3112 				incompat);
3113 		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
3114 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
3115 	} else {
3116 		jbd2_journal_clear_features(sbi->s_journal,
3117 				JBD2_FEATURE_COMPAT_CHECKSUM, 0,
3118 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT |
3119 				JBD2_FEATURE_INCOMPAT_CSUM_V2);
3120 	}
3121 
3122 	return ret;
3123 }
3124 
3125 /*
3126  * Note: calculating the overhead so we can be compatible with
3127  * historical BSD practice is quite difficult in the face of
3128  * clusters/bigalloc.  This is because multiple metadata blocks from
3129  * different block group can end up in the same allocation cluster.
3130  * Calculating the exact overhead in the face of clustered allocation
3131  * requires either O(all block bitmaps) in memory or O(number of block
3132  * groups**2) in time.  We will still calculate the superblock for
3133  * older file systems --- and if we come across with a bigalloc file
3134  * system with zero in s_overhead_clusters the estimate will be close to
3135  * correct especially for very large cluster sizes --- but for newer
3136  * file systems, it's better to calculate this figure once at mkfs
3137  * time, and store it in the superblock.  If the superblock value is
3138  * present (even for non-bigalloc file systems), we will use it.
3139  */
3140 static int count_overhead(struct super_block *sb, ext4_group_t grp,
3141 			  char *buf)
3142 {
3143 	struct ext4_sb_info	*sbi = EXT4_SB(sb);
3144 	struct ext4_group_desc	*gdp;
3145 	ext4_fsblk_t		first_block, last_block, b;
3146 	ext4_group_t		i, ngroups = ext4_get_groups_count(sb);
3147 	int			s, j, count = 0;
3148 
3149 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_BIGALLOC))
3150 		return (ext4_bg_has_super(sb, grp) + ext4_bg_num_gdb(sb, grp) +
3151 			sbi->s_itb_per_group + 2);
3152 
3153 	first_block = le32_to_cpu(sbi->s_es->s_first_data_block) +
3154 		(grp * EXT4_BLOCKS_PER_GROUP(sb));
3155 	last_block = first_block + EXT4_BLOCKS_PER_GROUP(sb) - 1;
3156 	for (i = 0; i < ngroups; i++) {
3157 		gdp = ext4_get_group_desc(sb, i, NULL);
3158 		b = ext4_block_bitmap(sb, gdp);
3159 		if (b >= first_block && b <= last_block) {
3160 			ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf);
3161 			count++;
3162 		}
3163 		b = ext4_inode_bitmap(sb, gdp);
3164 		if (b >= first_block && b <= last_block) {
3165 			ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf);
3166 			count++;
3167 		}
3168 		b = ext4_inode_table(sb, gdp);
3169 		if (b >= first_block && b + sbi->s_itb_per_group <= last_block)
3170 			for (j = 0; j < sbi->s_itb_per_group; j++, b++) {
3171 				int c = EXT4_B2C(sbi, b - first_block);
3172 				ext4_set_bit(c, buf);
3173 				count++;
3174 			}
3175 		if (i != grp)
3176 			continue;
3177 		s = 0;
3178 		if (ext4_bg_has_super(sb, grp)) {
3179 			ext4_set_bit(s++, buf);
3180 			count++;
3181 		}
3182 		for (j = ext4_bg_num_gdb(sb, grp); j > 0; j--) {
3183 			ext4_set_bit(EXT4_B2C(sbi, s++), buf);
3184 			count++;
3185 		}
3186 	}
3187 	if (!count)
3188 		return 0;
3189 	return EXT4_CLUSTERS_PER_GROUP(sb) -
3190 		ext4_count_free(buf, EXT4_CLUSTERS_PER_GROUP(sb) / 8);
3191 }
3192 
3193 /*
3194  * Compute the overhead and stash it in sbi->s_overhead
3195  */
3196 int ext4_calculate_overhead(struct super_block *sb)
3197 {
3198 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3199 	struct ext4_super_block *es = sbi->s_es;
3200 	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
3201 	ext4_fsblk_t overhead = 0;
3202 	char *buf = (char *) get_zeroed_page(GFP_KERNEL);
3203 
3204 	memset(buf, 0, PAGE_SIZE);
3205 	if (!buf)
3206 		return -ENOMEM;
3207 
3208 	/*
3209 	 * Compute the overhead (FS structures).  This is constant
3210 	 * for a given filesystem unless the number of block groups
3211 	 * changes so we cache the previous value until it does.
3212 	 */
3213 
3214 	/*
3215 	 * All of the blocks before first_data_block are overhead
3216 	 */
3217 	overhead = EXT4_B2C(sbi, le32_to_cpu(es->s_first_data_block));
3218 
3219 	/*
3220 	 * Add the overhead found in each block group
3221 	 */
3222 	for (i = 0; i < ngroups; i++) {
3223 		int blks;
3224 
3225 		blks = count_overhead(sb, i, buf);
3226 		overhead += blks;
3227 		if (blks)
3228 			memset(buf, 0, PAGE_SIZE);
3229 		cond_resched();
3230 	}
3231 	sbi->s_overhead = overhead;
3232 	smp_wmb();
3233 	free_page((unsigned long) buf);
3234 	return 0;
3235 }
3236 
3237 static int ext4_fill_super(struct super_block *sb, void *data, int silent)
3238 {
3239 	char *orig_data = kstrdup(data, GFP_KERNEL);
3240 	struct buffer_head *bh;
3241 	struct ext4_super_block *es = NULL;
3242 	struct ext4_sb_info *sbi;
3243 	ext4_fsblk_t block;
3244 	ext4_fsblk_t sb_block = get_sb_block(&data);
3245 	ext4_fsblk_t logical_sb_block;
3246 	unsigned long offset = 0;
3247 	unsigned long journal_devnum = 0;
3248 	unsigned long def_mount_opts;
3249 	struct inode *root;
3250 	char *cp;
3251 	const char *descr;
3252 	int ret = -ENOMEM;
3253 	int blocksize, clustersize;
3254 	unsigned int db_count;
3255 	unsigned int i;
3256 	int needs_recovery, has_huge_files, has_bigalloc;
3257 	__u64 blocks_count;
3258 	int err;
3259 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
3260 	ext4_group_t first_not_zeroed;
3261 
3262 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
3263 	if (!sbi)
3264 		goto out_free_orig;
3265 
3266 	sbi->s_blockgroup_lock =
3267 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
3268 	if (!sbi->s_blockgroup_lock) {
3269 		kfree(sbi);
3270 		goto out_free_orig;
3271 	}
3272 	sb->s_fs_info = sbi;
3273 	sbi->s_sb = sb;
3274 	sbi->s_mount_opt = 0;
3275 	sbi->s_resuid = make_kuid(&init_user_ns, EXT4_DEF_RESUID);
3276 	sbi->s_resgid = make_kgid(&init_user_ns, EXT4_DEF_RESGID);
3277 	sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
3278 	sbi->s_sb_block = sb_block;
3279 	if (sb->s_bdev->bd_part)
3280 		sbi->s_sectors_written_start =
3281 			part_stat_read(sb->s_bdev->bd_part, sectors[1]);
3282 
3283 	/* Cleanup superblock name */
3284 	for (cp = sb->s_id; (cp = strchr(cp, '/'));)
3285 		*cp = '!';
3286 
3287 	ret = -EINVAL;
3288 	blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
3289 	if (!blocksize) {
3290 		ext4_msg(sb, KERN_ERR, "unable to set blocksize");
3291 		goto out_fail;
3292 	}
3293 
3294 	/*
3295 	 * The ext4 superblock will not be buffer aligned for other than 1kB
3296 	 * block sizes.  We need to calculate the offset from buffer start.
3297 	 */
3298 	if (blocksize != EXT4_MIN_BLOCK_SIZE) {
3299 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3300 		offset = do_div(logical_sb_block, blocksize);
3301 	} else {
3302 		logical_sb_block = sb_block;
3303 	}
3304 
3305 	if (!(bh = sb_bread(sb, logical_sb_block))) {
3306 		ext4_msg(sb, KERN_ERR, "unable to read superblock");
3307 		goto out_fail;
3308 	}
3309 	/*
3310 	 * Note: s_es must be initialized as soon as possible because
3311 	 *       some ext4 macro-instructions depend on its value
3312 	 */
3313 	es = (struct ext4_super_block *) (bh->b_data + offset);
3314 	sbi->s_es = es;
3315 	sb->s_magic = le16_to_cpu(es->s_magic);
3316 	if (sb->s_magic != EXT4_SUPER_MAGIC)
3317 		goto cantfind_ext4;
3318 	sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
3319 
3320 	/* Warn if metadata_csum and gdt_csum are both set. */
3321 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3322 				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
3323 	    EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
3324 		ext4_warning(sb, KERN_INFO "metadata_csum and uninit_bg are "
3325 			     "redundant flags; please run fsck.");
3326 
3327 	/* Check for a known checksum algorithm */
3328 	if (!ext4_verify_csum_type(sb, es)) {
3329 		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
3330 			 "unknown checksum algorithm.");
3331 		silent = 1;
3332 		goto cantfind_ext4;
3333 	}
3334 
3335 	/* Load the checksum driver */
3336 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3337 				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
3338 		sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
3339 		if (IS_ERR(sbi->s_chksum_driver)) {
3340 			ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
3341 			ret = PTR_ERR(sbi->s_chksum_driver);
3342 			sbi->s_chksum_driver = NULL;
3343 			goto failed_mount;
3344 		}
3345 	}
3346 
3347 	/* Check superblock checksum */
3348 	if (!ext4_superblock_csum_verify(sb, es)) {
3349 		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
3350 			 "invalid superblock checksum.  Run e2fsck?");
3351 		silent = 1;
3352 		goto cantfind_ext4;
3353 	}
3354 
3355 	/* Precompute checksum seed for all metadata */
3356 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3357 			EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
3358 		sbi->s_csum_seed = ext4_chksum(sbi, ~0, es->s_uuid,
3359 					       sizeof(es->s_uuid));
3360 
3361 	/* Set defaults before we parse the mount options */
3362 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
3363 	set_opt(sb, INIT_INODE_TABLE);
3364 	if (def_mount_opts & EXT4_DEFM_DEBUG)
3365 		set_opt(sb, DEBUG);
3366 	if (def_mount_opts & EXT4_DEFM_BSDGROUPS)
3367 		set_opt(sb, GRPID);
3368 	if (def_mount_opts & EXT4_DEFM_UID16)
3369 		set_opt(sb, NO_UID32);
3370 	/* xattr user namespace & acls are now defaulted on */
3371 #ifdef CONFIG_EXT4_FS_XATTR
3372 	set_opt(sb, XATTR_USER);
3373 #endif
3374 #ifdef CONFIG_EXT4_FS_POSIX_ACL
3375 	set_opt(sb, POSIX_ACL);
3376 #endif
3377 	set_opt(sb, MBLK_IO_SUBMIT);
3378 	if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA)
3379 		set_opt(sb, JOURNAL_DATA);
3380 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_ORDERED)
3381 		set_opt(sb, ORDERED_DATA);
3382 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_WBACK)
3383 		set_opt(sb, WRITEBACK_DATA);
3384 
3385 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_PANIC)
3386 		set_opt(sb, ERRORS_PANIC);
3387 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_CONTINUE)
3388 		set_opt(sb, ERRORS_CONT);
3389 	else
3390 		set_opt(sb, ERRORS_RO);
3391 	if (def_mount_opts & EXT4_DEFM_BLOCK_VALIDITY)
3392 		set_opt(sb, BLOCK_VALIDITY);
3393 	if (def_mount_opts & EXT4_DEFM_DISCARD)
3394 		set_opt(sb, DISCARD);
3395 
3396 	sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
3397 	sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
3398 	sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ;
3399 	sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;
3400 	sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;
3401 
3402 	if ((def_mount_opts & EXT4_DEFM_NOBARRIER) == 0)
3403 		set_opt(sb, BARRIER);
3404 
3405 	/*
3406 	 * enable delayed allocation by default
3407 	 * Use -o nodelalloc to turn it off
3408 	 */
3409 	if (!IS_EXT3_SB(sb) && !IS_EXT2_SB(sb) &&
3410 	    ((def_mount_opts & EXT4_DEFM_NODELALLOC) == 0))
3411 		set_opt(sb, DELALLOC);
3412 
3413 	/*
3414 	 * set default s_li_wait_mult for lazyinit, for the case there is
3415 	 * no mount option specified.
3416 	 */
3417 	sbi->s_li_wait_mult = EXT4_DEF_LI_WAIT_MULT;
3418 
3419 	if (!parse_options((char *) sbi->s_es->s_mount_opts, sb,
3420 			   &journal_devnum, &journal_ioprio, 0)) {
3421 		ext4_msg(sb, KERN_WARNING,
3422 			 "failed to parse options in superblock: %s",
3423 			 sbi->s_es->s_mount_opts);
3424 	}
3425 	sbi->s_def_mount_opt = sbi->s_mount_opt;
3426 	if (!parse_options((char *) data, sb, &journal_devnum,
3427 			   &journal_ioprio, 0))
3428 		goto failed_mount;
3429 
3430 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
3431 		printk_once(KERN_WARNING "EXT4-fs: Warning: mounting "
3432 			    "with data=journal disables delayed "
3433 			    "allocation and O_DIRECT support!\n");
3434 		if (test_opt2(sb, EXPLICIT_DELALLOC)) {
3435 			ext4_msg(sb, KERN_ERR, "can't mount with "
3436 				 "both data=journal and delalloc");
3437 			goto failed_mount;
3438 		}
3439 		if (test_opt(sb, DIOREAD_NOLOCK)) {
3440 			ext4_msg(sb, KERN_ERR, "can't mount with "
3441 				 "both data=journal and delalloc");
3442 			goto failed_mount;
3443 		}
3444 		if (test_opt(sb, DELALLOC))
3445 			clear_opt(sb, DELALLOC);
3446 	}
3447 
3448 	blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
3449 	if (test_opt(sb, DIOREAD_NOLOCK)) {
3450 		if (blocksize < PAGE_SIZE) {
3451 			ext4_msg(sb, KERN_ERR, "can't mount with "
3452 				 "dioread_nolock if block size != PAGE_SIZE");
3453 			goto failed_mount;
3454 		}
3455 	}
3456 
3457 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
3458 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
3459 
3460 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
3461 	    (EXT4_HAS_COMPAT_FEATURE(sb, ~0U) ||
3462 	     EXT4_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
3463 	     EXT4_HAS_INCOMPAT_FEATURE(sb, ~0U)))
3464 		ext4_msg(sb, KERN_WARNING,
3465 		       "feature flags set on rev 0 fs, "
3466 		       "running e2fsck is recommended");
3467 
3468 	if (IS_EXT2_SB(sb)) {
3469 		if (ext2_feature_set_ok(sb))
3470 			ext4_msg(sb, KERN_INFO, "mounting ext2 file system "
3471 				 "using the ext4 subsystem");
3472 		else {
3473 			ext4_msg(sb, KERN_ERR, "couldn't mount as ext2 due "
3474 				 "to feature incompatibilities");
3475 			goto failed_mount;
3476 		}
3477 	}
3478 
3479 	if (IS_EXT3_SB(sb)) {
3480 		if (ext3_feature_set_ok(sb))
3481 			ext4_msg(sb, KERN_INFO, "mounting ext3 file system "
3482 				 "using the ext4 subsystem");
3483 		else {
3484 			ext4_msg(sb, KERN_ERR, "couldn't mount as ext3 due "
3485 				 "to feature incompatibilities");
3486 			goto failed_mount;
3487 		}
3488 	}
3489 
3490 	/*
3491 	 * Check feature flags regardless of the revision level, since we
3492 	 * previously didn't change the revision level when setting the flags,
3493 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
3494 	 */
3495 	if (!ext4_feature_set_ok(sb, (sb->s_flags & MS_RDONLY)))
3496 		goto failed_mount;
3497 
3498 	if (blocksize < EXT4_MIN_BLOCK_SIZE ||
3499 	    blocksize > EXT4_MAX_BLOCK_SIZE) {
3500 		ext4_msg(sb, KERN_ERR,
3501 		       "Unsupported filesystem blocksize %d", blocksize);
3502 		goto failed_mount;
3503 	}
3504 
3505 	if (sb->s_blocksize != blocksize) {
3506 		/* Validate the filesystem blocksize */
3507 		if (!sb_set_blocksize(sb, blocksize)) {
3508 			ext4_msg(sb, KERN_ERR, "bad block size %d",
3509 					blocksize);
3510 			goto failed_mount;
3511 		}
3512 
3513 		brelse(bh);
3514 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3515 		offset = do_div(logical_sb_block, blocksize);
3516 		bh = sb_bread(sb, logical_sb_block);
3517 		if (!bh) {
3518 			ext4_msg(sb, KERN_ERR,
3519 			       "Can't read superblock on 2nd try");
3520 			goto failed_mount;
3521 		}
3522 		es = (struct ext4_super_block *)(bh->b_data + offset);
3523 		sbi->s_es = es;
3524 		if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
3525 			ext4_msg(sb, KERN_ERR,
3526 			       "Magic mismatch, very weird!");
3527 			goto failed_mount;
3528 		}
3529 	}
3530 
3531 	has_huge_files = EXT4_HAS_RO_COMPAT_FEATURE(sb,
3532 				EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
3533 	sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits,
3534 						      has_huge_files);
3535 	sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits, has_huge_files);
3536 
3537 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) {
3538 		sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE;
3539 		sbi->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
3540 	} else {
3541 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
3542 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
3543 		if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
3544 		    (!is_power_of_2(sbi->s_inode_size)) ||
3545 		    (sbi->s_inode_size > blocksize)) {
3546 			ext4_msg(sb, KERN_ERR,
3547 			       "unsupported inode size: %d",
3548 			       sbi->s_inode_size);
3549 			goto failed_mount;
3550 		}
3551 		if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE)
3552 			sb->s_time_gran = 1 << (EXT4_EPOCH_BITS - 2);
3553 	}
3554 
3555 	sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
3556 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT)) {
3557 		if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT ||
3558 		    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
3559 		    !is_power_of_2(sbi->s_desc_size)) {
3560 			ext4_msg(sb, KERN_ERR,
3561 			       "unsupported descriptor size %lu",
3562 			       sbi->s_desc_size);
3563 			goto failed_mount;
3564 		}
3565 	} else
3566 		sbi->s_desc_size = EXT4_MIN_DESC_SIZE;
3567 
3568 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
3569 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
3570 	if (EXT4_INODE_SIZE(sb) == 0 || EXT4_INODES_PER_GROUP(sb) == 0)
3571 		goto cantfind_ext4;
3572 
3573 	sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
3574 	if (sbi->s_inodes_per_block == 0)
3575 		goto cantfind_ext4;
3576 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
3577 					sbi->s_inodes_per_block;
3578 	sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
3579 	sbi->s_sbh = bh;
3580 	sbi->s_mount_state = le16_to_cpu(es->s_state);
3581 	sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
3582 	sbi->s_desc_per_block_bits = ilog2(EXT4_DESC_PER_BLOCK(sb));
3583 
3584 	for (i = 0; i < 4; i++)
3585 		sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
3586 	sbi->s_def_hash_version = es->s_def_hash_version;
3587 	i = le32_to_cpu(es->s_flags);
3588 	if (i & EXT2_FLAGS_UNSIGNED_HASH)
3589 		sbi->s_hash_unsigned = 3;
3590 	else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) {
3591 #ifdef __CHAR_UNSIGNED__
3592 		es->s_flags |= cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH);
3593 		sbi->s_hash_unsigned = 3;
3594 #else
3595 		es->s_flags |= cpu_to_le32(EXT2_FLAGS_SIGNED_HASH);
3596 #endif
3597 	}
3598 
3599 	/* Handle clustersize */
3600 	clustersize = BLOCK_SIZE << le32_to_cpu(es->s_log_cluster_size);
3601 	has_bigalloc = EXT4_HAS_RO_COMPAT_FEATURE(sb,
3602 				EXT4_FEATURE_RO_COMPAT_BIGALLOC);
3603 	if (has_bigalloc) {
3604 		if (clustersize < blocksize) {
3605 			ext4_msg(sb, KERN_ERR,
3606 				 "cluster size (%d) smaller than "
3607 				 "block size (%d)", clustersize, blocksize);
3608 			goto failed_mount;
3609 		}
3610 		sbi->s_cluster_bits = le32_to_cpu(es->s_log_cluster_size) -
3611 			le32_to_cpu(es->s_log_block_size);
3612 		sbi->s_clusters_per_group =
3613 			le32_to_cpu(es->s_clusters_per_group);
3614 		if (sbi->s_clusters_per_group > blocksize * 8) {
3615 			ext4_msg(sb, KERN_ERR,
3616 				 "#clusters per group too big: %lu",
3617 				 sbi->s_clusters_per_group);
3618 			goto failed_mount;
3619 		}
3620 		if (sbi->s_blocks_per_group !=
3621 		    (sbi->s_clusters_per_group * (clustersize / blocksize))) {
3622 			ext4_msg(sb, KERN_ERR, "blocks per group (%lu) and "
3623 				 "clusters per group (%lu) inconsistent",
3624 				 sbi->s_blocks_per_group,
3625 				 sbi->s_clusters_per_group);
3626 			goto failed_mount;
3627 		}
3628 	} else {
3629 		if (clustersize != blocksize) {
3630 			ext4_warning(sb, "fragment/cluster size (%d) != "
3631 				     "block size (%d)", clustersize,
3632 				     blocksize);
3633 			clustersize = blocksize;
3634 		}
3635 		if (sbi->s_blocks_per_group > blocksize * 8) {
3636 			ext4_msg(sb, KERN_ERR,
3637 				 "#blocks per group too big: %lu",
3638 				 sbi->s_blocks_per_group);
3639 			goto failed_mount;
3640 		}
3641 		sbi->s_clusters_per_group = sbi->s_blocks_per_group;
3642 		sbi->s_cluster_bits = 0;
3643 	}
3644 	sbi->s_cluster_ratio = clustersize / blocksize;
3645 
3646 	if (sbi->s_inodes_per_group > blocksize * 8) {
3647 		ext4_msg(sb, KERN_ERR,
3648 		       "#inodes per group too big: %lu",
3649 		       sbi->s_inodes_per_group);
3650 		goto failed_mount;
3651 	}
3652 
3653 	/*
3654 	 * Test whether we have more sectors than will fit in sector_t,
3655 	 * and whether the max offset is addressable by the page cache.
3656 	 */
3657 	err = generic_check_addressable(sb->s_blocksize_bits,
3658 					ext4_blocks_count(es));
3659 	if (err) {
3660 		ext4_msg(sb, KERN_ERR, "filesystem"
3661 			 " too large to mount safely on this system");
3662 		if (sizeof(sector_t) < 8)
3663 			ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled");
3664 		ret = err;
3665 		goto failed_mount;
3666 	}
3667 
3668 	if (EXT4_BLOCKS_PER_GROUP(sb) == 0)
3669 		goto cantfind_ext4;
3670 
3671 	/* check blocks count against device size */
3672 	blocks_count = sb->s_bdev->bd_inode->i_size >> sb->s_blocksize_bits;
3673 	if (blocks_count && ext4_blocks_count(es) > blocks_count) {
3674 		ext4_msg(sb, KERN_WARNING, "bad geometry: block count %llu "
3675 		       "exceeds size of device (%llu blocks)",
3676 		       ext4_blocks_count(es), blocks_count);
3677 		goto failed_mount;
3678 	}
3679 
3680 	/*
3681 	 * It makes no sense for the first data block to be beyond the end
3682 	 * of the filesystem.
3683 	 */
3684 	if (le32_to_cpu(es->s_first_data_block) >= ext4_blocks_count(es)) {
3685 		ext4_msg(sb, KERN_WARNING, "bad geometry: first data "
3686 			 "block %u is beyond end of filesystem (%llu)",
3687 			 le32_to_cpu(es->s_first_data_block),
3688 			 ext4_blocks_count(es));
3689 		goto failed_mount;
3690 	}
3691 	blocks_count = (ext4_blocks_count(es) -
3692 			le32_to_cpu(es->s_first_data_block) +
3693 			EXT4_BLOCKS_PER_GROUP(sb) - 1);
3694 	do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
3695 	if (blocks_count > ((uint64_t)1<<32) - EXT4_DESC_PER_BLOCK(sb)) {
3696 		ext4_msg(sb, KERN_WARNING, "groups count too large: %u "
3697 		       "(block count %llu, first data block %u, "
3698 		       "blocks per group %lu)", sbi->s_groups_count,
3699 		       ext4_blocks_count(es),
3700 		       le32_to_cpu(es->s_first_data_block),
3701 		       EXT4_BLOCKS_PER_GROUP(sb));
3702 		goto failed_mount;
3703 	}
3704 	sbi->s_groups_count = blocks_count;
3705 	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
3706 			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
3707 	db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
3708 		   EXT4_DESC_PER_BLOCK(sb);
3709 	sbi->s_group_desc = ext4_kvmalloc(db_count *
3710 					  sizeof(struct buffer_head *),
3711 					  GFP_KERNEL);
3712 	if (sbi->s_group_desc == NULL) {
3713 		ext4_msg(sb, KERN_ERR, "not enough memory");
3714 		ret = -ENOMEM;
3715 		goto failed_mount;
3716 	}
3717 
3718 	if (ext4_proc_root)
3719 		sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
3720 
3721 	if (sbi->s_proc)
3722 		proc_create_data("options", S_IRUGO, sbi->s_proc,
3723 				 &ext4_seq_options_fops, sb);
3724 
3725 	bgl_lock_init(sbi->s_blockgroup_lock);
3726 
3727 	for (i = 0; i < db_count; i++) {
3728 		block = descriptor_loc(sb, logical_sb_block, i);
3729 		sbi->s_group_desc[i] = sb_bread(sb, block);
3730 		if (!sbi->s_group_desc[i]) {
3731 			ext4_msg(sb, KERN_ERR,
3732 			       "can't read group descriptor %d", i);
3733 			db_count = i;
3734 			goto failed_mount2;
3735 		}
3736 	}
3737 	if (!ext4_check_descriptors(sb, &first_not_zeroed)) {
3738 		ext4_msg(sb, KERN_ERR, "group descriptors corrupted!");
3739 		goto failed_mount2;
3740 	}
3741 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
3742 		if (!ext4_fill_flex_info(sb)) {
3743 			ext4_msg(sb, KERN_ERR,
3744 			       "unable to initialize "
3745 			       "flex_bg meta info!");
3746 			goto failed_mount2;
3747 		}
3748 
3749 	sbi->s_gdb_count = db_count;
3750 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
3751 	spin_lock_init(&sbi->s_next_gen_lock);
3752 
3753 	init_timer(&sbi->s_err_report);
3754 	sbi->s_err_report.function = print_daily_error_info;
3755 	sbi->s_err_report.data = (unsigned long) sb;
3756 
3757 	err = percpu_counter_init(&sbi->s_freeclusters_counter,
3758 			ext4_count_free_clusters(sb));
3759 	if (!err) {
3760 		err = percpu_counter_init(&sbi->s_freeinodes_counter,
3761 				ext4_count_free_inodes(sb));
3762 	}
3763 	if (!err) {
3764 		err = percpu_counter_init(&sbi->s_dirs_counter,
3765 				ext4_count_dirs(sb));
3766 	}
3767 	if (!err) {
3768 		err = percpu_counter_init(&sbi->s_dirtyclusters_counter, 0);
3769 	}
3770 	if (err) {
3771 		ext4_msg(sb, KERN_ERR, "insufficient memory");
3772 		ret = err;
3773 		goto failed_mount3;
3774 	}
3775 
3776 	sbi->s_stripe = ext4_get_stripe_size(sbi);
3777 	sbi->s_max_writeback_mb_bump = 128;
3778 	sbi->s_extent_max_zeroout_kb = 32;
3779 
3780 	/*
3781 	 * set up enough so that it can read an inode
3782 	 */
3783 	if (!test_opt(sb, NOLOAD) &&
3784 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL))
3785 		sb->s_op = &ext4_sops;
3786 	else
3787 		sb->s_op = &ext4_nojournal_sops;
3788 	sb->s_export_op = &ext4_export_ops;
3789 	sb->s_xattr = ext4_xattr_handlers;
3790 #ifdef CONFIG_QUOTA
3791 	sb->s_qcop = &ext4_qctl_operations;
3792 	sb->dq_op = &ext4_quota_operations;
3793 
3794 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA)) {
3795 		/* Use qctl operations for hidden quota files. */
3796 		sb->s_qcop = &ext4_qctl_sysfile_operations;
3797 	}
3798 #endif
3799 	memcpy(sb->s_uuid, es->s_uuid, sizeof(es->s_uuid));
3800 
3801 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
3802 	mutex_init(&sbi->s_orphan_lock);
3803 	sbi->s_resize_flags = 0;
3804 
3805 	sb->s_root = NULL;
3806 
3807 	needs_recovery = (es->s_last_orphan != 0 ||
3808 			  EXT4_HAS_INCOMPAT_FEATURE(sb,
3809 				    EXT4_FEATURE_INCOMPAT_RECOVER));
3810 
3811 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_MMP) &&
3812 	    !(sb->s_flags & MS_RDONLY))
3813 		if (ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block)))
3814 			goto failed_mount3;
3815 
3816 	/*
3817 	 * The first inode we look at is the journal inode.  Don't try
3818 	 * root first: it may be modified in the journal!
3819 	 */
3820 	if (!test_opt(sb, NOLOAD) &&
3821 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
3822 		if (ext4_load_journal(sb, es, journal_devnum))
3823 			goto failed_mount3;
3824 	} else if (test_opt(sb, NOLOAD) && !(sb->s_flags & MS_RDONLY) &&
3825 	      EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
3826 		ext4_msg(sb, KERN_ERR, "required journal recovery "
3827 		       "suppressed and not mounted read-only");
3828 		goto failed_mount_wq;
3829 	} else {
3830 		clear_opt(sb, DATA_FLAGS);
3831 		sbi->s_journal = NULL;
3832 		needs_recovery = 0;
3833 		goto no_journal;
3834 	}
3835 
3836 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT) &&
3837 	    !jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
3838 				       JBD2_FEATURE_INCOMPAT_64BIT)) {
3839 		ext4_msg(sb, KERN_ERR, "Failed to set 64-bit journal feature");
3840 		goto failed_mount_wq;
3841 	}
3842 
3843 	if (!set_journal_csum_feature_set(sb)) {
3844 		ext4_msg(sb, KERN_ERR, "Failed to set journal checksum "
3845 			 "feature set");
3846 		goto failed_mount_wq;
3847 	}
3848 
3849 	/* We have now updated the journal if required, so we can
3850 	 * validate the data journaling mode. */
3851 	switch (test_opt(sb, DATA_FLAGS)) {
3852 	case 0:
3853 		/* No mode set, assume a default based on the journal
3854 		 * capabilities: ORDERED_DATA if the journal can
3855 		 * cope, else JOURNAL_DATA
3856 		 */
3857 		if (jbd2_journal_check_available_features
3858 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE))
3859 			set_opt(sb, ORDERED_DATA);
3860 		else
3861 			set_opt(sb, JOURNAL_DATA);
3862 		break;
3863 
3864 	case EXT4_MOUNT_ORDERED_DATA:
3865 	case EXT4_MOUNT_WRITEBACK_DATA:
3866 		if (!jbd2_journal_check_available_features
3867 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
3868 			ext4_msg(sb, KERN_ERR, "Journal does not support "
3869 			       "requested data journaling mode");
3870 			goto failed_mount_wq;
3871 		}
3872 	default:
3873 		break;
3874 	}
3875 	set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
3876 
3877 	sbi->s_journal->j_commit_callback = ext4_journal_commit_callback;
3878 
3879 	/*
3880 	 * The journal may have updated the bg summary counts, so we
3881 	 * need to update the global counters.
3882 	 */
3883 	percpu_counter_set(&sbi->s_freeclusters_counter,
3884 			   ext4_count_free_clusters(sb));
3885 	percpu_counter_set(&sbi->s_freeinodes_counter,
3886 			   ext4_count_free_inodes(sb));
3887 	percpu_counter_set(&sbi->s_dirs_counter,
3888 			   ext4_count_dirs(sb));
3889 	percpu_counter_set(&sbi->s_dirtyclusters_counter, 0);
3890 
3891 no_journal:
3892 	/*
3893 	 * Get the # of file system overhead blocks from the
3894 	 * superblock if present.
3895 	 */
3896 	if (es->s_overhead_clusters)
3897 		sbi->s_overhead = le32_to_cpu(es->s_overhead_clusters);
3898 	else {
3899 		ret = ext4_calculate_overhead(sb);
3900 		if (ret)
3901 			goto failed_mount_wq;
3902 	}
3903 
3904 	/*
3905 	 * The maximum number of concurrent works can be high and
3906 	 * concurrency isn't really necessary.  Limit it to 1.
3907 	 */
3908 	EXT4_SB(sb)->dio_unwritten_wq =
3909 		alloc_workqueue("ext4-dio-unwritten", WQ_MEM_RECLAIM | WQ_UNBOUND, 1);
3910 	if (!EXT4_SB(sb)->dio_unwritten_wq) {
3911 		printk(KERN_ERR "EXT4-fs: failed to create DIO workqueue\n");
3912 		goto failed_mount_wq;
3913 	}
3914 
3915 	/*
3916 	 * The jbd2_journal_load will have done any necessary log recovery,
3917 	 * so we can safely mount the rest of the filesystem now.
3918 	 */
3919 
3920 	root = ext4_iget(sb, EXT4_ROOT_INO);
3921 	if (IS_ERR(root)) {
3922 		ext4_msg(sb, KERN_ERR, "get root inode failed");
3923 		ret = PTR_ERR(root);
3924 		root = NULL;
3925 		goto failed_mount4;
3926 	}
3927 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
3928 		ext4_msg(sb, KERN_ERR, "corrupt root inode, run e2fsck");
3929 		iput(root);
3930 		goto failed_mount4;
3931 	}
3932 	sb->s_root = d_make_root(root);
3933 	if (!sb->s_root) {
3934 		ext4_msg(sb, KERN_ERR, "get root dentry failed");
3935 		ret = -ENOMEM;
3936 		goto failed_mount4;
3937 	}
3938 
3939 	if (ext4_setup_super(sb, es, sb->s_flags & MS_RDONLY))
3940 		sb->s_flags |= MS_RDONLY;
3941 
3942 	/* determine the minimum size of new large inodes, if present */
3943 	if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
3944 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
3945 						     EXT4_GOOD_OLD_INODE_SIZE;
3946 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3947 				       EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE)) {
3948 			if (sbi->s_want_extra_isize <
3949 			    le16_to_cpu(es->s_want_extra_isize))
3950 				sbi->s_want_extra_isize =
3951 					le16_to_cpu(es->s_want_extra_isize);
3952 			if (sbi->s_want_extra_isize <
3953 			    le16_to_cpu(es->s_min_extra_isize))
3954 				sbi->s_want_extra_isize =
3955 					le16_to_cpu(es->s_min_extra_isize);
3956 		}
3957 	}
3958 	/* Check if enough inode space is available */
3959 	if (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize >
3960 							sbi->s_inode_size) {
3961 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
3962 						       EXT4_GOOD_OLD_INODE_SIZE;
3963 		ext4_msg(sb, KERN_INFO, "required extra inode space not"
3964 			 "available");
3965 	}
3966 
3967 	err = ext4_setup_system_zone(sb);
3968 	if (err) {
3969 		ext4_msg(sb, KERN_ERR, "failed to initialize system "
3970 			 "zone (%d)", err);
3971 		goto failed_mount4a;
3972 	}
3973 
3974 	ext4_ext_init(sb);
3975 	err = ext4_mb_init(sb);
3976 	if (err) {
3977 		ext4_msg(sb, KERN_ERR, "failed to initialize mballoc (%d)",
3978 			 err);
3979 		goto failed_mount5;
3980 	}
3981 
3982 	err = ext4_register_li_request(sb, first_not_zeroed);
3983 	if (err)
3984 		goto failed_mount6;
3985 
3986 	sbi->s_kobj.kset = ext4_kset;
3987 	init_completion(&sbi->s_kobj_unregister);
3988 	err = kobject_init_and_add(&sbi->s_kobj, &ext4_ktype, NULL,
3989 				   "%s", sb->s_id);
3990 	if (err)
3991 		goto failed_mount7;
3992 
3993 	EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
3994 	ext4_orphan_cleanup(sb, es);
3995 	EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
3996 	if (needs_recovery) {
3997 		ext4_msg(sb, KERN_INFO, "recovery complete");
3998 		ext4_mark_recovery_complete(sb, es);
3999 	}
4000 	if (EXT4_SB(sb)->s_journal) {
4001 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
4002 			descr = " journalled data mode";
4003 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
4004 			descr = " ordered data mode";
4005 		else
4006 			descr = " writeback data mode";
4007 	} else
4008 		descr = "out journal";
4009 
4010 #ifdef CONFIG_QUOTA
4011 	/* Enable quota usage during mount. */
4012 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA) &&
4013 	    !(sb->s_flags & MS_RDONLY)) {
4014 		ret = ext4_enable_quotas(sb);
4015 		if (ret)
4016 			goto failed_mount7;
4017 	}
4018 #endif  /* CONFIG_QUOTA */
4019 
4020 	ext4_msg(sb, KERN_INFO, "mounted filesystem with%s. "
4021 		 "Opts: %s%s%s", descr, sbi->s_es->s_mount_opts,
4022 		 *sbi->s_es->s_mount_opts ? "; " : "", orig_data);
4023 
4024 	if (es->s_error_count)
4025 		mod_timer(&sbi->s_err_report, jiffies + 300*HZ); /* 5 minutes */
4026 
4027 	kfree(orig_data);
4028 	return 0;
4029 
4030 cantfind_ext4:
4031 	if (!silent)
4032 		ext4_msg(sb, KERN_ERR, "VFS: Can't find ext4 filesystem");
4033 	goto failed_mount;
4034 
4035 failed_mount7:
4036 	ext4_unregister_li_request(sb);
4037 failed_mount6:
4038 	ext4_mb_release(sb);
4039 failed_mount5:
4040 	ext4_ext_release(sb);
4041 	ext4_release_system_zone(sb);
4042 failed_mount4a:
4043 	dput(sb->s_root);
4044 	sb->s_root = NULL;
4045 failed_mount4:
4046 	ext4_msg(sb, KERN_ERR, "mount failed");
4047 	destroy_workqueue(EXT4_SB(sb)->dio_unwritten_wq);
4048 failed_mount_wq:
4049 	if (sbi->s_journal) {
4050 		jbd2_journal_destroy(sbi->s_journal);
4051 		sbi->s_journal = NULL;
4052 	}
4053 failed_mount3:
4054 	del_timer(&sbi->s_err_report);
4055 	if (sbi->s_flex_groups)
4056 		ext4_kvfree(sbi->s_flex_groups);
4057 	percpu_counter_destroy(&sbi->s_freeclusters_counter);
4058 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
4059 	percpu_counter_destroy(&sbi->s_dirs_counter);
4060 	percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
4061 	if (sbi->s_mmp_tsk)
4062 		kthread_stop(sbi->s_mmp_tsk);
4063 failed_mount2:
4064 	for (i = 0; i < db_count; i++)
4065 		brelse(sbi->s_group_desc[i]);
4066 	ext4_kvfree(sbi->s_group_desc);
4067 failed_mount:
4068 	if (sbi->s_chksum_driver)
4069 		crypto_free_shash(sbi->s_chksum_driver);
4070 	if (sbi->s_proc) {
4071 		remove_proc_entry("options", sbi->s_proc);
4072 		remove_proc_entry(sb->s_id, ext4_proc_root);
4073 	}
4074 #ifdef CONFIG_QUOTA
4075 	for (i = 0; i < MAXQUOTAS; i++)
4076 		kfree(sbi->s_qf_names[i]);
4077 #endif
4078 	ext4_blkdev_remove(sbi);
4079 	brelse(bh);
4080 out_fail:
4081 	sb->s_fs_info = NULL;
4082 	kfree(sbi->s_blockgroup_lock);
4083 	kfree(sbi);
4084 out_free_orig:
4085 	kfree(orig_data);
4086 	return ret;
4087 }
4088 
4089 /*
4090  * Setup any per-fs journal parameters now.  We'll do this both on
4091  * initial mount, once the journal has been initialised but before we've
4092  * done any recovery; and again on any subsequent remount.
4093  */
4094 static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
4095 {
4096 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4097 
4098 	journal->j_commit_interval = sbi->s_commit_interval;
4099 	journal->j_min_batch_time = sbi->s_min_batch_time;
4100 	journal->j_max_batch_time = sbi->s_max_batch_time;
4101 
4102 	write_lock(&journal->j_state_lock);
4103 	if (test_opt(sb, BARRIER))
4104 		journal->j_flags |= JBD2_BARRIER;
4105 	else
4106 		journal->j_flags &= ~JBD2_BARRIER;
4107 	if (test_opt(sb, DATA_ERR_ABORT))
4108 		journal->j_flags |= JBD2_ABORT_ON_SYNCDATA_ERR;
4109 	else
4110 		journal->j_flags &= ~JBD2_ABORT_ON_SYNCDATA_ERR;
4111 	write_unlock(&journal->j_state_lock);
4112 }
4113 
4114 static journal_t *ext4_get_journal(struct super_block *sb,
4115 				   unsigned int journal_inum)
4116 {
4117 	struct inode *journal_inode;
4118 	journal_t *journal;
4119 
4120 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4121 
4122 	/* First, test for the existence of a valid inode on disk.  Bad
4123 	 * things happen if we iget() an unused inode, as the subsequent
4124 	 * iput() will try to delete it. */
4125 
4126 	journal_inode = ext4_iget(sb, journal_inum);
4127 	if (IS_ERR(journal_inode)) {
4128 		ext4_msg(sb, KERN_ERR, "no journal found");
4129 		return NULL;
4130 	}
4131 	if (!journal_inode->i_nlink) {
4132 		make_bad_inode(journal_inode);
4133 		iput(journal_inode);
4134 		ext4_msg(sb, KERN_ERR, "journal inode is deleted");
4135 		return NULL;
4136 	}
4137 
4138 	jbd_debug(2, "Journal inode found at %p: %lld bytes\n",
4139 		  journal_inode, journal_inode->i_size);
4140 	if (!S_ISREG(journal_inode->i_mode)) {
4141 		ext4_msg(sb, KERN_ERR, "invalid journal inode");
4142 		iput(journal_inode);
4143 		return NULL;
4144 	}
4145 
4146 	journal = jbd2_journal_init_inode(journal_inode);
4147 	if (!journal) {
4148 		ext4_msg(sb, KERN_ERR, "Could not load journal inode");
4149 		iput(journal_inode);
4150 		return NULL;
4151 	}
4152 	journal->j_private = sb;
4153 	ext4_init_journal_params(sb, journal);
4154 	return journal;
4155 }
4156 
4157 static journal_t *ext4_get_dev_journal(struct super_block *sb,
4158 				       dev_t j_dev)
4159 {
4160 	struct buffer_head *bh;
4161 	journal_t *journal;
4162 	ext4_fsblk_t start;
4163 	ext4_fsblk_t len;
4164 	int hblock, blocksize;
4165 	ext4_fsblk_t sb_block;
4166 	unsigned long offset;
4167 	struct ext4_super_block *es;
4168 	struct block_device *bdev;
4169 
4170 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4171 
4172 	bdev = ext4_blkdev_get(j_dev, sb);
4173 	if (bdev == NULL)
4174 		return NULL;
4175 
4176 	blocksize = sb->s_blocksize;
4177 	hblock = bdev_logical_block_size(bdev);
4178 	if (blocksize < hblock) {
4179 		ext4_msg(sb, KERN_ERR,
4180 			"blocksize too small for journal device");
4181 		goto out_bdev;
4182 	}
4183 
4184 	sb_block = EXT4_MIN_BLOCK_SIZE / blocksize;
4185 	offset = EXT4_MIN_BLOCK_SIZE % blocksize;
4186 	set_blocksize(bdev, blocksize);
4187 	if (!(bh = __bread(bdev, sb_block, blocksize))) {
4188 		ext4_msg(sb, KERN_ERR, "couldn't read superblock of "
4189 		       "external journal");
4190 		goto out_bdev;
4191 	}
4192 
4193 	es = (struct ext4_super_block *) (bh->b_data + offset);
4194 	if ((le16_to_cpu(es->s_magic) != EXT4_SUPER_MAGIC) ||
4195 	    !(le32_to_cpu(es->s_feature_incompat) &
4196 	      EXT4_FEATURE_INCOMPAT_JOURNAL_DEV)) {
4197 		ext4_msg(sb, KERN_ERR, "external journal has "
4198 					"bad superblock");
4199 		brelse(bh);
4200 		goto out_bdev;
4201 	}
4202 
4203 	if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
4204 		ext4_msg(sb, KERN_ERR, "journal UUID does not match");
4205 		brelse(bh);
4206 		goto out_bdev;
4207 	}
4208 
4209 	len = ext4_blocks_count(es);
4210 	start = sb_block + 1;
4211 	brelse(bh);	/* we're done with the superblock */
4212 
4213 	journal = jbd2_journal_init_dev(bdev, sb->s_bdev,
4214 					start, len, blocksize);
4215 	if (!journal) {
4216 		ext4_msg(sb, KERN_ERR, "failed to create device journal");
4217 		goto out_bdev;
4218 	}
4219 	journal->j_private = sb;
4220 	ll_rw_block(READ, 1, &journal->j_sb_buffer);
4221 	wait_on_buffer(journal->j_sb_buffer);
4222 	if (!buffer_uptodate(journal->j_sb_buffer)) {
4223 		ext4_msg(sb, KERN_ERR, "I/O error on journal device");
4224 		goto out_journal;
4225 	}
4226 	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
4227 		ext4_msg(sb, KERN_ERR, "External journal has more than one "
4228 					"user (unsupported) - %d",
4229 			be32_to_cpu(journal->j_superblock->s_nr_users));
4230 		goto out_journal;
4231 	}
4232 	EXT4_SB(sb)->journal_bdev = bdev;
4233 	ext4_init_journal_params(sb, journal);
4234 	return journal;
4235 
4236 out_journal:
4237 	jbd2_journal_destroy(journal);
4238 out_bdev:
4239 	ext4_blkdev_put(bdev);
4240 	return NULL;
4241 }
4242 
4243 static int ext4_load_journal(struct super_block *sb,
4244 			     struct ext4_super_block *es,
4245 			     unsigned long journal_devnum)
4246 {
4247 	journal_t *journal;
4248 	unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
4249 	dev_t journal_dev;
4250 	int err = 0;
4251 	int really_read_only;
4252 
4253 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4254 
4255 	if (journal_devnum &&
4256 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
4257 		ext4_msg(sb, KERN_INFO, "external journal device major/minor "
4258 			"numbers have changed");
4259 		journal_dev = new_decode_dev(journal_devnum);
4260 	} else
4261 		journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));
4262 
4263 	really_read_only = bdev_read_only(sb->s_bdev);
4264 
4265 	/*
4266 	 * Are we loading a blank journal or performing recovery after a
4267 	 * crash?  For recovery, we need to check in advance whether we
4268 	 * can get read-write access to the device.
4269 	 */
4270 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
4271 		if (sb->s_flags & MS_RDONLY) {
4272 			ext4_msg(sb, KERN_INFO, "INFO: recovery "
4273 					"required on readonly filesystem");
4274 			if (really_read_only) {
4275 				ext4_msg(sb, KERN_ERR, "write access "
4276 					"unavailable, cannot proceed");
4277 				return -EROFS;
4278 			}
4279 			ext4_msg(sb, KERN_INFO, "write access will "
4280 			       "be enabled during recovery");
4281 		}
4282 	}
4283 
4284 	if (journal_inum && journal_dev) {
4285 		ext4_msg(sb, KERN_ERR, "filesystem has both journal "
4286 		       "and inode journals!");
4287 		return -EINVAL;
4288 	}
4289 
4290 	if (journal_inum) {
4291 		if (!(journal = ext4_get_journal(sb, journal_inum)))
4292 			return -EINVAL;
4293 	} else {
4294 		if (!(journal = ext4_get_dev_journal(sb, journal_dev)))
4295 			return -EINVAL;
4296 	}
4297 
4298 	if (!(journal->j_flags & JBD2_BARRIER))
4299 		ext4_msg(sb, KERN_INFO, "barriers disabled");
4300 
4301 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER))
4302 		err = jbd2_journal_wipe(journal, !really_read_only);
4303 	if (!err) {
4304 		char *save = kmalloc(EXT4_S_ERR_LEN, GFP_KERNEL);
4305 		if (save)
4306 			memcpy(save, ((char *) es) +
4307 			       EXT4_S_ERR_START, EXT4_S_ERR_LEN);
4308 		err = jbd2_journal_load(journal);
4309 		if (save)
4310 			memcpy(((char *) es) + EXT4_S_ERR_START,
4311 			       save, EXT4_S_ERR_LEN);
4312 		kfree(save);
4313 	}
4314 
4315 	if (err) {
4316 		ext4_msg(sb, KERN_ERR, "error loading journal");
4317 		jbd2_journal_destroy(journal);
4318 		return err;
4319 	}
4320 
4321 	EXT4_SB(sb)->s_journal = journal;
4322 	ext4_clear_journal_err(sb, es);
4323 
4324 	if (!really_read_only && journal_devnum &&
4325 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
4326 		es->s_journal_dev = cpu_to_le32(journal_devnum);
4327 
4328 		/* Make sure we flush the recovery flag to disk. */
4329 		ext4_commit_super(sb, 1);
4330 	}
4331 
4332 	return 0;
4333 }
4334 
4335 static int ext4_commit_super(struct super_block *sb, int sync)
4336 {
4337 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
4338 	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
4339 	int error = 0;
4340 
4341 	if (!sbh || block_device_ejected(sb))
4342 		return error;
4343 	if (buffer_write_io_error(sbh)) {
4344 		/*
4345 		 * Oh, dear.  A previous attempt to write the
4346 		 * superblock failed.  This could happen because the
4347 		 * USB device was yanked out.  Or it could happen to
4348 		 * be a transient write error and maybe the block will
4349 		 * be remapped.  Nothing we can do but to retry the
4350 		 * write and hope for the best.
4351 		 */
4352 		ext4_msg(sb, KERN_ERR, "previous I/O error to "
4353 		       "superblock detected");
4354 		clear_buffer_write_io_error(sbh);
4355 		set_buffer_uptodate(sbh);
4356 	}
4357 	/*
4358 	 * If the file system is mounted read-only, don't update the
4359 	 * superblock write time.  This avoids updating the superblock
4360 	 * write time when we are mounting the root file system
4361 	 * read/only but we need to replay the journal; at that point,
4362 	 * for people who are east of GMT and who make their clock
4363 	 * tick in localtime for Windows bug-for-bug compatibility,
4364 	 * the clock is set in the future, and this will cause e2fsck
4365 	 * to complain and force a full file system check.
4366 	 */
4367 	if (!(sb->s_flags & MS_RDONLY))
4368 		es->s_wtime = cpu_to_le32(get_seconds());
4369 	if (sb->s_bdev->bd_part)
4370 		es->s_kbytes_written =
4371 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written +
4372 			    ((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
4373 			      EXT4_SB(sb)->s_sectors_written_start) >> 1));
4374 	else
4375 		es->s_kbytes_written =
4376 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written);
4377 	ext4_free_blocks_count_set(es,
4378 			EXT4_C2B(EXT4_SB(sb), percpu_counter_sum_positive(
4379 				&EXT4_SB(sb)->s_freeclusters_counter)));
4380 	es->s_free_inodes_count =
4381 		cpu_to_le32(percpu_counter_sum_positive(
4382 				&EXT4_SB(sb)->s_freeinodes_counter));
4383 	BUFFER_TRACE(sbh, "marking dirty");
4384 	ext4_superblock_csum_set(sb, es);
4385 	mark_buffer_dirty(sbh);
4386 	if (sync) {
4387 		error = sync_dirty_buffer(sbh);
4388 		if (error)
4389 			return error;
4390 
4391 		error = buffer_write_io_error(sbh);
4392 		if (error) {
4393 			ext4_msg(sb, KERN_ERR, "I/O error while writing "
4394 			       "superblock");
4395 			clear_buffer_write_io_error(sbh);
4396 			set_buffer_uptodate(sbh);
4397 		}
4398 	}
4399 	return error;
4400 }
4401 
4402 /*
4403  * Have we just finished recovery?  If so, and if we are mounting (or
4404  * remounting) the filesystem readonly, then we will end up with a
4405  * consistent fs on disk.  Record that fact.
4406  */
4407 static void ext4_mark_recovery_complete(struct super_block *sb,
4408 					struct ext4_super_block *es)
4409 {
4410 	journal_t *journal = EXT4_SB(sb)->s_journal;
4411 
4412 	if (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
4413 		BUG_ON(journal != NULL);
4414 		return;
4415 	}
4416 	jbd2_journal_lock_updates(journal);
4417 	if (jbd2_journal_flush(journal) < 0)
4418 		goto out;
4419 
4420 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER) &&
4421 	    sb->s_flags & MS_RDONLY) {
4422 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4423 		ext4_commit_super(sb, 1);
4424 	}
4425 
4426 out:
4427 	jbd2_journal_unlock_updates(journal);
4428 }
4429 
4430 /*
4431  * If we are mounting (or read-write remounting) a filesystem whose journal
4432  * has recorded an error from a previous lifetime, move that error to the
4433  * main filesystem now.
4434  */
4435 static void ext4_clear_journal_err(struct super_block *sb,
4436 				   struct ext4_super_block *es)
4437 {
4438 	journal_t *journal;
4439 	int j_errno;
4440 	const char *errstr;
4441 
4442 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4443 
4444 	journal = EXT4_SB(sb)->s_journal;
4445 
4446 	/*
4447 	 * Now check for any error status which may have been recorded in the
4448 	 * journal by a prior ext4_error() or ext4_abort()
4449 	 */
4450 
4451 	j_errno = jbd2_journal_errno(journal);
4452 	if (j_errno) {
4453 		char nbuf[16];
4454 
4455 		errstr = ext4_decode_error(sb, j_errno, nbuf);
4456 		ext4_warning(sb, "Filesystem error recorded "
4457 			     "from previous mount: %s", errstr);
4458 		ext4_warning(sb, "Marking fs in need of filesystem check.");
4459 
4460 		EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
4461 		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
4462 		ext4_commit_super(sb, 1);
4463 
4464 		jbd2_journal_clear_err(journal);
4465 		jbd2_journal_update_sb_errno(journal);
4466 	}
4467 }
4468 
4469 /*
4470  * Force the running and committing transactions to commit,
4471  * and wait on the commit.
4472  */
4473 int ext4_force_commit(struct super_block *sb)
4474 {
4475 	journal_t *journal;
4476 	int ret = 0;
4477 
4478 	if (sb->s_flags & MS_RDONLY)
4479 		return 0;
4480 
4481 	journal = EXT4_SB(sb)->s_journal;
4482 	if (journal)
4483 		ret = ext4_journal_force_commit(journal);
4484 
4485 	return ret;
4486 }
4487 
4488 static int ext4_sync_fs(struct super_block *sb, int wait)
4489 {
4490 	int ret = 0;
4491 	tid_t target;
4492 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4493 
4494 	trace_ext4_sync_fs(sb, wait);
4495 	flush_workqueue(sbi->dio_unwritten_wq);
4496 	/*
4497 	 * Writeback quota in non-journalled quota case - journalled quota has
4498 	 * no dirty dquots
4499 	 */
4500 	dquot_writeback_dquots(sb, -1);
4501 	if (jbd2_journal_start_commit(sbi->s_journal, &target)) {
4502 		if (wait)
4503 			jbd2_log_wait_commit(sbi->s_journal, target);
4504 	}
4505 	return ret;
4506 }
4507 
4508 /*
4509  * LVM calls this function before a (read-only) snapshot is created.  This
4510  * gives us a chance to flush the journal completely and mark the fs clean.
4511  *
4512  * Note that only this function cannot bring a filesystem to be in a clean
4513  * state independently. It relies on upper layer to stop all data & metadata
4514  * modifications.
4515  */
4516 static int ext4_freeze(struct super_block *sb)
4517 {
4518 	int error = 0;
4519 	journal_t *journal;
4520 
4521 	if (sb->s_flags & MS_RDONLY)
4522 		return 0;
4523 
4524 	journal = EXT4_SB(sb)->s_journal;
4525 
4526 	/* Now we set up the journal barrier. */
4527 	jbd2_journal_lock_updates(journal);
4528 
4529 	/*
4530 	 * Don't clear the needs_recovery flag if we failed to flush
4531 	 * the journal.
4532 	 */
4533 	error = jbd2_journal_flush(journal);
4534 	if (error < 0)
4535 		goto out;
4536 
4537 	/* Journal blocked and flushed, clear needs_recovery flag. */
4538 	EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4539 	error = ext4_commit_super(sb, 1);
4540 out:
4541 	/* we rely on upper layer to stop further updates */
4542 	jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
4543 	return error;
4544 }
4545 
4546 /*
4547  * Called by LVM after the snapshot is done.  We need to reset the RECOVER
4548  * flag here, even though the filesystem is not technically dirty yet.
4549  */
4550 static int ext4_unfreeze(struct super_block *sb)
4551 {
4552 	if (sb->s_flags & MS_RDONLY)
4553 		return 0;
4554 
4555 	/* Reset the needs_recovery flag before the fs is unlocked. */
4556 	EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4557 	ext4_commit_super(sb, 1);
4558 	return 0;
4559 }
4560 
4561 /*
4562  * Structure to save mount options for ext4_remount's benefit
4563  */
4564 struct ext4_mount_options {
4565 	unsigned long s_mount_opt;
4566 	unsigned long s_mount_opt2;
4567 	kuid_t s_resuid;
4568 	kgid_t s_resgid;
4569 	unsigned long s_commit_interval;
4570 	u32 s_min_batch_time, s_max_batch_time;
4571 #ifdef CONFIG_QUOTA
4572 	int s_jquota_fmt;
4573 	char *s_qf_names[MAXQUOTAS];
4574 #endif
4575 };
4576 
4577 static int ext4_remount(struct super_block *sb, int *flags, char *data)
4578 {
4579 	struct ext4_super_block *es;
4580 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4581 	unsigned long old_sb_flags;
4582 	struct ext4_mount_options old_opts;
4583 	int enable_quota = 0;
4584 	ext4_group_t g;
4585 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
4586 	int err = 0;
4587 #ifdef CONFIG_QUOTA
4588 	int i;
4589 #endif
4590 	char *orig_data = kstrdup(data, GFP_KERNEL);
4591 
4592 	/* Store the original options */
4593 	old_sb_flags = sb->s_flags;
4594 	old_opts.s_mount_opt = sbi->s_mount_opt;
4595 	old_opts.s_mount_opt2 = sbi->s_mount_opt2;
4596 	old_opts.s_resuid = sbi->s_resuid;
4597 	old_opts.s_resgid = sbi->s_resgid;
4598 	old_opts.s_commit_interval = sbi->s_commit_interval;
4599 	old_opts.s_min_batch_time = sbi->s_min_batch_time;
4600 	old_opts.s_max_batch_time = sbi->s_max_batch_time;
4601 #ifdef CONFIG_QUOTA
4602 	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
4603 	for (i = 0; i < MAXQUOTAS; i++)
4604 		old_opts.s_qf_names[i] = sbi->s_qf_names[i];
4605 #endif
4606 	if (sbi->s_journal && sbi->s_journal->j_task->io_context)
4607 		journal_ioprio = sbi->s_journal->j_task->io_context->ioprio;
4608 
4609 	/*
4610 	 * Allow the "check" option to be passed as a remount option.
4611 	 */
4612 	if (!parse_options(data, sb, NULL, &journal_ioprio, 1)) {
4613 		err = -EINVAL;
4614 		goto restore_opts;
4615 	}
4616 
4617 	if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
4618 		ext4_abort(sb, "Abort forced by user");
4619 
4620 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
4621 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
4622 
4623 	es = sbi->s_es;
4624 
4625 	if (sbi->s_journal) {
4626 		ext4_init_journal_params(sb, sbi->s_journal);
4627 		set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
4628 	}
4629 
4630 	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY)) {
4631 		if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) {
4632 			err = -EROFS;
4633 			goto restore_opts;
4634 		}
4635 
4636 		if (*flags & MS_RDONLY) {
4637 			err = dquot_suspend(sb, -1);
4638 			if (err < 0)
4639 				goto restore_opts;
4640 
4641 			/*
4642 			 * First of all, the unconditional stuff we have to do
4643 			 * to disable replay of the journal when we next remount
4644 			 */
4645 			sb->s_flags |= MS_RDONLY;
4646 
4647 			/*
4648 			 * OK, test if we are remounting a valid rw partition
4649 			 * readonly, and if so set the rdonly flag and then
4650 			 * mark the partition as valid again.
4651 			 */
4652 			if (!(es->s_state & cpu_to_le16(EXT4_VALID_FS)) &&
4653 			    (sbi->s_mount_state & EXT4_VALID_FS))
4654 				es->s_state = cpu_to_le16(sbi->s_mount_state);
4655 
4656 			if (sbi->s_journal)
4657 				ext4_mark_recovery_complete(sb, es);
4658 		} else {
4659 			/* Make sure we can mount this feature set readwrite */
4660 			if (!ext4_feature_set_ok(sb, 0)) {
4661 				err = -EROFS;
4662 				goto restore_opts;
4663 			}
4664 			/*
4665 			 * Make sure the group descriptor checksums
4666 			 * are sane.  If they aren't, refuse to remount r/w.
4667 			 */
4668 			for (g = 0; g < sbi->s_groups_count; g++) {
4669 				struct ext4_group_desc *gdp =
4670 					ext4_get_group_desc(sb, g, NULL);
4671 
4672 				if (!ext4_group_desc_csum_verify(sb, g, gdp)) {
4673 					ext4_msg(sb, KERN_ERR,
4674 	       "ext4_remount: Checksum for group %u failed (%u!=%u)",
4675 		g, le16_to_cpu(ext4_group_desc_csum(sbi, g, gdp)),
4676 					       le16_to_cpu(gdp->bg_checksum));
4677 					err = -EINVAL;
4678 					goto restore_opts;
4679 				}
4680 			}
4681 
4682 			/*
4683 			 * If we have an unprocessed orphan list hanging
4684 			 * around from a previously readonly bdev mount,
4685 			 * require a full umount/remount for now.
4686 			 */
4687 			if (es->s_last_orphan) {
4688 				ext4_msg(sb, KERN_WARNING, "Couldn't "
4689 				       "remount RDWR because of unprocessed "
4690 				       "orphan inode list.  Please "
4691 				       "umount/remount instead");
4692 				err = -EINVAL;
4693 				goto restore_opts;
4694 			}
4695 
4696 			/*
4697 			 * Mounting a RDONLY partition read-write, so reread
4698 			 * and store the current valid flag.  (It may have
4699 			 * been changed by e2fsck since we originally mounted
4700 			 * the partition.)
4701 			 */
4702 			if (sbi->s_journal)
4703 				ext4_clear_journal_err(sb, es);
4704 			sbi->s_mount_state = le16_to_cpu(es->s_state);
4705 			if (!ext4_setup_super(sb, es, 0))
4706 				sb->s_flags &= ~MS_RDONLY;
4707 			if (EXT4_HAS_INCOMPAT_FEATURE(sb,
4708 						     EXT4_FEATURE_INCOMPAT_MMP))
4709 				if (ext4_multi_mount_protect(sb,
4710 						le64_to_cpu(es->s_mmp_block))) {
4711 					err = -EROFS;
4712 					goto restore_opts;
4713 				}
4714 			enable_quota = 1;
4715 		}
4716 	}
4717 
4718 	/*
4719 	 * Reinitialize lazy itable initialization thread based on
4720 	 * current settings
4721 	 */
4722 	if ((sb->s_flags & MS_RDONLY) || !test_opt(sb, INIT_INODE_TABLE))
4723 		ext4_unregister_li_request(sb);
4724 	else {
4725 		ext4_group_t first_not_zeroed;
4726 		first_not_zeroed = ext4_has_uninit_itable(sb);
4727 		ext4_register_li_request(sb, first_not_zeroed);
4728 	}
4729 
4730 	ext4_setup_system_zone(sb);
4731 	if (sbi->s_journal == NULL)
4732 		ext4_commit_super(sb, 1);
4733 
4734 #ifdef CONFIG_QUOTA
4735 	/* Release old quota file names */
4736 	for (i = 0; i < MAXQUOTAS; i++)
4737 		if (old_opts.s_qf_names[i] &&
4738 		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
4739 			kfree(old_opts.s_qf_names[i]);
4740 	if (enable_quota) {
4741 		if (sb_any_quota_suspended(sb))
4742 			dquot_resume(sb, -1);
4743 		else if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
4744 					EXT4_FEATURE_RO_COMPAT_QUOTA)) {
4745 			err = ext4_enable_quotas(sb);
4746 			if (err)
4747 				goto restore_opts;
4748 		}
4749 	}
4750 #endif
4751 
4752 	ext4_msg(sb, KERN_INFO, "re-mounted. Opts: %s", orig_data);
4753 	kfree(orig_data);
4754 	return 0;
4755 
4756 restore_opts:
4757 	sb->s_flags = old_sb_flags;
4758 	sbi->s_mount_opt = old_opts.s_mount_opt;
4759 	sbi->s_mount_opt2 = old_opts.s_mount_opt2;
4760 	sbi->s_resuid = old_opts.s_resuid;
4761 	sbi->s_resgid = old_opts.s_resgid;
4762 	sbi->s_commit_interval = old_opts.s_commit_interval;
4763 	sbi->s_min_batch_time = old_opts.s_min_batch_time;
4764 	sbi->s_max_batch_time = old_opts.s_max_batch_time;
4765 #ifdef CONFIG_QUOTA
4766 	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
4767 	for (i = 0; i < MAXQUOTAS; i++) {
4768 		if (sbi->s_qf_names[i] &&
4769 		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
4770 			kfree(sbi->s_qf_names[i]);
4771 		sbi->s_qf_names[i] = old_opts.s_qf_names[i];
4772 	}
4773 #endif
4774 	kfree(orig_data);
4775 	return err;
4776 }
4777 
4778 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
4779 {
4780 	struct super_block *sb = dentry->d_sb;
4781 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4782 	struct ext4_super_block *es = sbi->s_es;
4783 	ext4_fsblk_t overhead = 0;
4784 	u64 fsid;
4785 	s64 bfree;
4786 
4787 	if (!test_opt(sb, MINIX_DF))
4788 		overhead = sbi->s_overhead;
4789 
4790 	buf->f_type = EXT4_SUPER_MAGIC;
4791 	buf->f_bsize = sb->s_blocksize;
4792 	buf->f_blocks = ext4_blocks_count(es) - EXT4_C2B(sbi, sbi->s_overhead);
4793 	bfree = percpu_counter_sum_positive(&sbi->s_freeclusters_counter) -
4794 		percpu_counter_sum_positive(&sbi->s_dirtyclusters_counter);
4795 	/* prevent underflow in case that few free space is available */
4796 	buf->f_bfree = EXT4_C2B(sbi, max_t(s64, bfree, 0));
4797 	buf->f_bavail = buf->f_bfree - ext4_r_blocks_count(es);
4798 	if (buf->f_bfree < ext4_r_blocks_count(es))
4799 		buf->f_bavail = 0;
4800 	buf->f_files = le32_to_cpu(es->s_inodes_count);
4801 	buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter);
4802 	buf->f_namelen = EXT4_NAME_LEN;
4803 	fsid = le64_to_cpup((void *)es->s_uuid) ^
4804 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
4805 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
4806 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
4807 
4808 	return 0;
4809 }
4810 
4811 /* Helper function for writing quotas on sync - we need to start transaction
4812  * before quota file is locked for write. Otherwise the are possible deadlocks:
4813  * Process 1                         Process 2
4814  * ext4_create()                     quota_sync()
4815  *   jbd2_journal_start()                  write_dquot()
4816  *   dquot_initialize()                         down(dqio_mutex)
4817  *     down(dqio_mutex)                    jbd2_journal_start()
4818  *
4819  */
4820 
4821 #ifdef CONFIG_QUOTA
4822 
4823 static inline struct inode *dquot_to_inode(struct dquot *dquot)
4824 {
4825 	return sb_dqopt(dquot->dq_sb)->files[dquot->dq_id.type];
4826 }
4827 
4828 static int ext4_write_dquot(struct dquot *dquot)
4829 {
4830 	int ret, err;
4831 	handle_t *handle;
4832 	struct inode *inode;
4833 
4834 	inode = dquot_to_inode(dquot);
4835 	handle = ext4_journal_start(inode,
4836 				    EXT4_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
4837 	if (IS_ERR(handle))
4838 		return PTR_ERR(handle);
4839 	ret = dquot_commit(dquot);
4840 	err = ext4_journal_stop(handle);
4841 	if (!ret)
4842 		ret = err;
4843 	return ret;
4844 }
4845 
4846 static int ext4_acquire_dquot(struct dquot *dquot)
4847 {
4848 	int ret, err;
4849 	handle_t *handle;
4850 
4851 	handle = ext4_journal_start(dquot_to_inode(dquot),
4852 				    EXT4_QUOTA_INIT_BLOCKS(dquot->dq_sb));
4853 	if (IS_ERR(handle))
4854 		return PTR_ERR(handle);
4855 	ret = dquot_acquire(dquot);
4856 	err = ext4_journal_stop(handle);
4857 	if (!ret)
4858 		ret = err;
4859 	return ret;
4860 }
4861 
4862 static int ext4_release_dquot(struct dquot *dquot)
4863 {
4864 	int ret, err;
4865 	handle_t *handle;
4866 
4867 	handle = ext4_journal_start(dquot_to_inode(dquot),
4868 				    EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
4869 	if (IS_ERR(handle)) {
4870 		/* Release dquot anyway to avoid endless cycle in dqput() */
4871 		dquot_release(dquot);
4872 		return PTR_ERR(handle);
4873 	}
4874 	ret = dquot_release(dquot);
4875 	err = ext4_journal_stop(handle);
4876 	if (!ret)
4877 		ret = err;
4878 	return ret;
4879 }
4880 
4881 static int ext4_mark_dquot_dirty(struct dquot *dquot)
4882 {
4883 	/* Are we journaling quotas? */
4884 	if (EXT4_SB(dquot->dq_sb)->s_qf_names[USRQUOTA] ||
4885 	    EXT4_SB(dquot->dq_sb)->s_qf_names[GRPQUOTA]) {
4886 		dquot_mark_dquot_dirty(dquot);
4887 		return ext4_write_dquot(dquot);
4888 	} else {
4889 		return dquot_mark_dquot_dirty(dquot);
4890 	}
4891 }
4892 
4893 static int ext4_write_info(struct super_block *sb, int type)
4894 {
4895 	int ret, err;
4896 	handle_t *handle;
4897 
4898 	/* Data block + inode block */
4899 	handle = ext4_journal_start(sb->s_root->d_inode, 2);
4900 	if (IS_ERR(handle))
4901 		return PTR_ERR(handle);
4902 	ret = dquot_commit_info(sb, type);
4903 	err = ext4_journal_stop(handle);
4904 	if (!ret)
4905 		ret = err;
4906 	return ret;
4907 }
4908 
4909 /*
4910  * Turn on quotas during mount time - we need to find
4911  * the quota file and such...
4912  */
4913 static int ext4_quota_on_mount(struct super_block *sb, int type)
4914 {
4915 	return dquot_quota_on_mount(sb, EXT4_SB(sb)->s_qf_names[type],
4916 					EXT4_SB(sb)->s_jquota_fmt, type);
4917 }
4918 
4919 /*
4920  * Standard function to be called on quota_on
4921  */
4922 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
4923 			 struct path *path)
4924 {
4925 	int err;
4926 
4927 	if (!test_opt(sb, QUOTA))
4928 		return -EINVAL;
4929 
4930 	/* Quotafile not on the same filesystem? */
4931 	if (path->dentry->d_sb != sb)
4932 		return -EXDEV;
4933 	/* Journaling quota? */
4934 	if (EXT4_SB(sb)->s_qf_names[type]) {
4935 		/* Quotafile not in fs root? */
4936 		if (path->dentry->d_parent != sb->s_root)
4937 			ext4_msg(sb, KERN_WARNING,
4938 				"Quota file not on filesystem root. "
4939 				"Journaled quota will not work");
4940 	}
4941 
4942 	/*
4943 	 * When we journal data on quota file, we have to flush journal to see
4944 	 * all updates to the file when we bypass pagecache...
4945 	 */
4946 	if (EXT4_SB(sb)->s_journal &&
4947 	    ext4_should_journal_data(path->dentry->d_inode)) {
4948 		/*
4949 		 * We don't need to lock updates but journal_flush() could
4950 		 * otherwise be livelocked...
4951 		 */
4952 		jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
4953 		err = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
4954 		jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
4955 		if (err)
4956 			return err;
4957 	}
4958 
4959 	return dquot_quota_on(sb, type, format_id, path);
4960 }
4961 
4962 static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
4963 			     unsigned int flags)
4964 {
4965 	int err;
4966 	struct inode *qf_inode;
4967 	unsigned long qf_inums[MAXQUOTAS] = {
4968 		le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
4969 		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum)
4970 	};
4971 
4972 	BUG_ON(!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA));
4973 
4974 	if (!qf_inums[type])
4975 		return -EPERM;
4976 
4977 	qf_inode = ext4_iget(sb, qf_inums[type]);
4978 	if (IS_ERR(qf_inode)) {
4979 		ext4_error(sb, "Bad quota inode # %lu", qf_inums[type]);
4980 		return PTR_ERR(qf_inode);
4981 	}
4982 
4983 	err = dquot_enable(qf_inode, type, format_id, flags);
4984 	iput(qf_inode);
4985 
4986 	return err;
4987 }
4988 
4989 /* Enable usage tracking for all quota types. */
4990 static int ext4_enable_quotas(struct super_block *sb)
4991 {
4992 	int type, err = 0;
4993 	unsigned long qf_inums[MAXQUOTAS] = {
4994 		le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
4995 		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum)
4996 	};
4997 
4998 	sb_dqopt(sb)->flags |= DQUOT_QUOTA_SYS_FILE;
4999 	for (type = 0; type < MAXQUOTAS; type++) {
5000 		if (qf_inums[type]) {
5001 			err = ext4_quota_enable(sb, type, QFMT_VFS_V1,
5002 						DQUOT_USAGE_ENABLED);
5003 			if (err) {
5004 				ext4_warning(sb,
5005 					"Failed to enable quota (type=%d) "
5006 					"tracking. Please run e2fsck to fix.",
5007 					type);
5008 				return err;
5009 			}
5010 		}
5011 	}
5012 	return 0;
5013 }
5014 
5015 /*
5016  * quota_on function that is used when QUOTA feature is set.
5017  */
5018 static int ext4_quota_on_sysfile(struct super_block *sb, int type,
5019 				 int format_id)
5020 {
5021 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA))
5022 		return -EINVAL;
5023 
5024 	/*
5025 	 * USAGE was enabled at mount time. Only need to enable LIMITS now.
5026 	 */
5027 	return ext4_quota_enable(sb, type, format_id, DQUOT_LIMITS_ENABLED);
5028 }
5029 
5030 static int ext4_quota_off(struct super_block *sb, int type)
5031 {
5032 	struct inode *inode = sb_dqopt(sb)->files[type];
5033 	handle_t *handle;
5034 
5035 	/* Force all delayed allocation blocks to be allocated.
5036 	 * Caller already holds s_umount sem */
5037 	if (test_opt(sb, DELALLOC))
5038 		sync_filesystem(sb);
5039 
5040 	if (!inode)
5041 		goto out;
5042 
5043 	/* Update modification times of quota files when userspace can
5044 	 * start looking at them */
5045 	handle = ext4_journal_start(inode, 1);
5046 	if (IS_ERR(handle))
5047 		goto out;
5048 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
5049 	ext4_mark_inode_dirty(handle, inode);
5050 	ext4_journal_stop(handle);
5051 
5052 out:
5053 	return dquot_quota_off(sb, type);
5054 }
5055 
5056 /*
5057  * quota_off function that is used when QUOTA feature is set.
5058  */
5059 static int ext4_quota_off_sysfile(struct super_block *sb, int type)
5060 {
5061 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA))
5062 		return -EINVAL;
5063 
5064 	/* Disable only the limits. */
5065 	return dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
5066 }
5067 
5068 /* Read data from quotafile - avoid pagecache and such because we cannot afford
5069  * acquiring the locks... As quota files are never truncated and quota code
5070  * itself serializes the operations (and no one else should touch the files)
5071  * we don't have to be afraid of races */
5072 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
5073 			       size_t len, loff_t off)
5074 {
5075 	struct inode *inode = sb_dqopt(sb)->files[type];
5076 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
5077 	int err = 0;
5078 	int offset = off & (sb->s_blocksize - 1);
5079 	int tocopy;
5080 	size_t toread;
5081 	struct buffer_head *bh;
5082 	loff_t i_size = i_size_read(inode);
5083 
5084 	if (off > i_size)
5085 		return 0;
5086 	if (off+len > i_size)
5087 		len = i_size-off;
5088 	toread = len;
5089 	while (toread > 0) {
5090 		tocopy = sb->s_blocksize - offset < toread ?
5091 				sb->s_blocksize - offset : toread;
5092 		bh = ext4_bread(NULL, inode, blk, 0, &err);
5093 		if (err)
5094 			return err;
5095 		if (!bh)	/* A hole? */
5096 			memset(data, 0, tocopy);
5097 		else
5098 			memcpy(data, bh->b_data+offset, tocopy);
5099 		brelse(bh);
5100 		offset = 0;
5101 		toread -= tocopy;
5102 		data += tocopy;
5103 		blk++;
5104 	}
5105 	return len;
5106 }
5107 
5108 /* Write to quotafile (we know the transaction is already started and has
5109  * enough credits) */
5110 static ssize_t ext4_quota_write(struct super_block *sb, int type,
5111 				const char *data, size_t len, loff_t off)
5112 {
5113 	struct inode *inode = sb_dqopt(sb)->files[type];
5114 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
5115 	int err = 0;
5116 	int offset = off & (sb->s_blocksize - 1);
5117 	struct buffer_head *bh;
5118 	handle_t *handle = journal_current_handle();
5119 
5120 	if (EXT4_SB(sb)->s_journal && !handle) {
5121 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
5122 			" cancelled because transaction is not started",
5123 			(unsigned long long)off, (unsigned long long)len);
5124 		return -EIO;
5125 	}
5126 	/*
5127 	 * Since we account only one data block in transaction credits,
5128 	 * then it is impossible to cross a block boundary.
5129 	 */
5130 	if (sb->s_blocksize - offset < len) {
5131 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
5132 			" cancelled because not block aligned",
5133 			(unsigned long long)off, (unsigned long long)len);
5134 		return -EIO;
5135 	}
5136 
5137 	bh = ext4_bread(handle, inode, blk, 1, &err);
5138 	if (!bh)
5139 		goto out;
5140 	err = ext4_journal_get_write_access(handle, bh);
5141 	if (err) {
5142 		brelse(bh);
5143 		goto out;
5144 	}
5145 	lock_buffer(bh);
5146 	memcpy(bh->b_data+offset, data, len);
5147 	flush_dcache_page(bh->b_page);
5148 	unlock_buffer(bh);
5149 	err = ext4_handle_dirty_metadata(handle, NULL, bh);
5150 	brelse(bh);
5151 out:
5152 	if (err)
5153 		return err;
5154 	if (inode->i_size < off + len) {
5155 		i_size_write(inode, off + len);
5156 		EXT4_I(inode)->i_disksize = inode->i_size;
5157 		ext4_mark_inode_dirty(handle, inode);
5158 	}
5159 	return len;
5160 }
5161 
5162 #endif
5163 
5164 static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
5165 		       const char *dev_name, void *data)
5166 {
5167 	return mount_bdev(fs_type, flags, dev_name, data, ext4_fill_super);
5168 }
5169 
5170 #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
5171 static inline void register_as_ext2(void)
5172 {
5173 	int err = register_filesystem(&ext2_fs_type);
5174 	if (err)
5175 		printk(KERN_WARNING
5176 		       "EXT4-fs: Unable to register as ext2 (%d)\n", err);
5177 }
5178 
5179 static inline void unregister_as_ext2(void)
5180 {
5181 	unregister_filesystem(&ext2_fs_type);
5182 }
5183 
5184 static inline int ext2_feature_set_ok(struct super_block *sb)
5185 {
5186 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP))
5187 		return 0;
5188 	if (sb->s_flags & MS_RDONLY)
5189 		return 1;
5190 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))
5191 		return 0;
5192 	return 1;
5193 }
5194 MODULE_ALIAS("ext2");
5195 #else
5196 static inline void register_as_ext2(void) { }
5197 static inline void unregister_as_ext2(void) { }
5198 static inline int ext2_feature_set_ok(struct super_block *sb) { return 0; }
5199 #endif
5200 
5201 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
5202 static inline void register_as_ext3(void)
5203 {
5204 	int err = register_filesystem(&ext3_fs_type);
5205 	if (err)
5206 		printk(KERN_WARNING
5207 		       "EXT4-fs: Unable to register as ext3 (%d)\n", err);
5208 }
5209 
5210 static inline void unregister_as_ext3(void)
5211 {
5212 	unregister_filesystem(&ext3_fs_type);
5213 }
5214 
5215 static inline int ext3_feature_set_ok(struct super_block *sb)
5216 {
5217 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT3_FEATURE_INCOMPAT_SUPP))
5218 		return 0;
5219 	if (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL))
5220 		return 0;
5221 	if (sb->s_flags & MS_RDONLY)
5222 		return 1;
5223 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT3_FEATURE_RO_COMPAT_SUPP))
5224 		return 0;
5225 	return 1;
5226 }
5227 MODULE_ALIAS("ext3");
5228 #else
5229 static inline void register_as_ext3(void) { }
5230 static inline void unregister_as_ext3(void) { }
5231 static inline int ext3_feature_set_ok(struct super_block *sb) { return 0; }
5232 #endif
5233 
5234 static struct file_system_type ext4_fs_type = {
5235 	.owner		= THIS_MODULE,
5236 	.name		= "ext4",
5237 	.mount		= ext4_mount,
5238 	.kill_sb	= kill_block_super,
5239 	.fs_flags	= FS_REQUIRES_DEV,
5240 };
5241 
5242 static int __init ext4_init_feat_adverts(void)
5243 {
5244 	struct ext4_features *ef;
5245 	int ret = -ENOMEM;
5246 
5247 	ef = kzalloc(sizeof(struct ext4_features), GFP_KERNEL);
5248 	if (!ef)
5249 		goto out;
5250 
5251 	ef->f_kobj.kset = ext4_kset;
5252 	init_completion(&ef->f_kobj_unregister);
5253 	ret = kobject_init_and_add(&ef->f_kobj, &ext4_feat_ktype, NULL,
5254 				   "features");
5255 	if (ret) {
5256 		kfree(ef);
5257 		goto out;
5258 	}
5259 
5260 	ext4_feat = ef;
5261 	ret = 0;
5262 out:
5263 	return ret;
5264 }
5265 
5266 static void ext4_exit_feat_adverts(void)
5267 {
5268 	kobject_put(&ext4_feat->f_kobj);
5269 	wait_for_completion(&ext4_feat->f_kobj_unregister);
5270 	kfree(ext4_feat);
5271 }
5272 
5273 /* Shared across all ext4 file systems */
5274 wait_queue_head_t ext4__ioend_wq[EXT4_WQ_HASH_SZ];
5275 struct mutex ext4__aio_mutex[EXT4_WQ_HASH_SZ];
5276 
5277 static int __init ext4_init_fs(void)
5278 {
5279 	int i, err;
5280 
5281 	ext4_li_info = NULL;
5282 	mutex_init(&ext4_li_mtx);
5283 
5284 	ext4_check_flag_values();
5285 
5286 	for (i = 0; i < EXT4_WQ_HASH_SZ; i++) {
5287 		mutex_init(&ext4__aio_mutex[i]);
5288 		init_waitqueue_head(&ext4__ioend_wq[i]);
5289 	}
5290 
5291 	err = ext4_init_pageio();
5292 	if (err)
5293 		return err;
5294 	err = ext4_init_system_zone();
5295 	if (err)
5296 		goto out6;
5297 	ext4_kset = kset_create_and_add("ext4", NULL, fs_kobj);
5298 	if (!ext4_kset) {
5299 		err = -ENOMEM;
5300 		goto out5;
5301 	}
5302 	ext4_proc_root = proc_mkdir("fs/ext4", NULL);
5303 
5304 	err = ext4_init_feat_adverts();
5305 	if (err)
5306 		goto out4;
5307 
5308 	err = ext4_init_mballoc();
5309 	if (err)
5310 		goto out3;
5311 
5312 	err = ext4_init_xattr();
5313 	if (err)
5314 		goto out2;
5315 	err = init_inodecache();
5316 	if (err)
5317 		goto out1;
5318 	register_as_ext3();
5319 	register_as_ext2();
5320 	err = register_filesystem(&ext4_fs_type);
5321 	if (err)
5322 		goto out;
5323 
5324 	return 0;
5325 out:
5326 	unregister_as_ext2();
5327 	unregister_as_ext3();
5328 	destroy_inodecache();
5329 out1:
5330 	ext4_exit_xattr();
5331 out2:
5332 	ext4_exit_mballoc();
5333 out3:
5334 	ext4_exit_feat_adverts();
5335 out4:
5336 	if (ext4_proc_root)
5337 		remove_proc_entry("fs/ext4", NULL);
5338 	kset_unregister(ext4_kset);
5339 out5:
5340 	ext4_exit_system_zone();
5341 out6:
5342 	ext4_exit_pageio();
5343 	return err;
5344 }
5345 
5346 static void __exit ext4_exit_fs(void)
5347 {
5348 	ext4_destroy_lazyinit_thread();
5349 	unregister_as_ext2();
5350 	unregister_as_ext3();
5351 	unregister_filesystem(&ext4_fs_type);
5352 	destroy_inodecache();
5353 	ext4_exit_xattr();
5354 	ext4_exit_mballoc();
5355 	ext4_exit_feat_adverts();
5356 	remove_proc_entry("fs/ext4", NULL);
5357 	kset_unregister(ext4_kset);
5358 	ext4_exit_system_zone();
5359 	ext4_exit_pageio();
5360 }
5361 
5362 MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
5363 MODULE_DESCRIPTION("Fourth Extended Filesystem");
5364 MODULE_LICENSE("GPL");
5365 module_init(ext4_init_fs)
5366 module_exit(ext4_exit_fs)
5367