xref: /openbmc/linux/fs/ext4/super.c (revision 404c3bc30cb1361e1b3533643326ab472d24a618)
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 void ext4_write_super(struct super_block *sb);
78 static int ext4_freeze(struct super_block *sb);
79 static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
80 		       const char *dev_name, void *data);
81 static inline int ext2_feature_set_ok(struct super_block *sb);
82 static inline int ext3_feature_set_ok(struct super_block *sb);
83 static int ext4_feature_set_ok(struct super_block *sb, int readonly);
84 static void ext4_destroy_lazyinit_thread(void);
85 static void ext4_unregister_li_request(struct super_block *sb);
86 static void ext4_clear_request_list(void);
87 
88 #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
89 static struct file_system_type ext2_fs_type = {
90 	.owner		= THIS_MODULE,
91 	.name		= "ext2",
92 	.mount		= ext4_mount,
93 	.kill_sb	= kill_block_super,
94 	.fs_flags	= FS_REQUIRES_DEV,
95 };
96 #define IS_EXT2_SB(sb) ((sb)->s_bdev->bd_holder == &ext2_fs_type)
97 #else
98 #define IS_EXT2_SB(sb) (0)
99 #endif
100 
101 
102 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
103 static struct file_system_type ext3_fs_type = {
104 	.owner		= THIS_MODULE,
105 	.name		= "ext3",
106 	.mount		= ext4_mount,
107 	.kill_sb	= kill_block_super,
108 	.fs_flags	= FS_REQUIRES_DEV,
109 };
110 #define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type)
111 #else
112 #define IS_EXT3_SB(sb) (0)
113 #endif
114 
115 static int ext4_verify_csum_type(struct super_block *sb,
116 				 struct ext4_super_block *es)
117 {
118 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
119 					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
120 		return 1;
121 
122 	return es->s_checksum_type == EXT4_CRC32C_CHKSUM;
123 }
124 
125 static __le32 ext4_superblock_csum(struct super_block *sb,
126 				   struct ext4_super_block *es)
127 {
128 	struct ext4_sb_info *sbi = EXT4_SB(sb);
129 	int offset = offsetof(struct ext4_super_block, s_checksum);
130 	__u32 csum;
131 
132 	csum = ext4_chksum(sbi, ~0, (char *)es, offset);
133 
134 	return cpu_to_le32(csum);
135 }
136 
137 int ext4_superblock_csum_verify(struct super_block *sb,
138 				struct ext4_super_block *es)
139 {
140 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
141 				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
142 		return 1;
143 
144 	return es->s_checksum == ext4_superblock_csum(sb, es);
145 }
146 
147 void ext4_superblock_csum_set(struct super_block *sb,
148 			      struct ext4_super_block *es)
149 {
150 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
151 		EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
152 		return;
153 
154 	es->s_checksum = ext4_superblock_csum(sb, es);
155 }
156 
157 void *ext4_kvmalloc(size_t size, gfp_t flags)
158 {
159 	void *ret;
160 
161 	ret = kmalloc(size, flags);
162 	if (!ret)
163 		ret = __vmalloc(size, flags, PAGE_KERNEL);
164 	return ret;
165 }
166 
167 void *ext4_kvzalloc(size_t size, gfp_t flags)
168 {
169 	void *ret;
170 
171 	ret = kzalloc(size, flags);
172 	if (!ret)
173 		ret = __vmalloc(size, flags | __GFP_ZERO, PAGE_KERNEL);
174 	return ret;
175 }
176 
177 void ext4_kvfree(void *ptr)
178 {
179 	if (is_vmalloc_addr(ptr))
180 		vfree(ptr);
181 	else
182 		kfree(ptr);
183 
184 }
185 
186 ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
187 			       struct ext4_group_desc *bg)
188 {
189 	return le32_to_cpu(bg->bg_block_bitmap_lo) |
190 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
191 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_block_bitmap_hi) << 32 : 0);
192 }
193 
194 ext4_fsblk_t ext4_inode_bitmap(struct super_block *sb,
195 			       struct ext4_group_desc *bg)
196 {
197 	return le32_to_cpu(bg->bg_inode_bitmap_lo) |
198 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
199 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_bitmap_hi) << 32 : 0);
200 }
201 
202 ext4_fsblk_t ext4_inode_table(struct super_block *sb,
203 			      struct ext4_group_desc *bg)
204 {
205 	return le32_to_cpu(bg->bg_inode_table_lo) |
206 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
207 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_table_hi) << 32 : 0);
208 }
209 
210 __u32 ext4_free_group_clusters(struct super_block *sb,
211 			       struct ext4_group_desc *bg)
212 {
213 	return le16_to_cpu(bg->bg_free_blocks_count_lo) |
214 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
215 		 (__u32)le16_to_cpu(bg->bg_free_blocks_count_hi) << 16 : 0);
216 }
217 
218 __u32 ext4_free_inodes_count(struct super_block *sb,
219 			      struct ext4_group_desc *bg)
220 {
221 	return le16_to_cpu(bg->bg_free_inodes_count_lo) |
222 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
223 		 (__u32)le16_to_cpu(bg->bg_free_inodes_count_hi) << 16 : 0);
224 }
225 
226 __u32 ext4_used_dirs_count(struct super_block *sb,
227 			      struct ext4_group_desc *bg)
228 {
229 	return le16_to_cpu(bg->bg_used_dirs_count_lo) |
230 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
231 		 (__u32)le16_to_cpu(bg->bg_used_dirs_count_hi) << 16 : 0);
232 }
233 
234 __u32 ext4_itable_unused_count(struct super_block *sb,
235 			      struct ext4_group_desc *bg)
236 {
237 	return le16_to_cpu(bg->bg_itable_unused_lo) |
238 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
239 		 (__u32)le16_to_cpu(bg->bg_itable_unused_hi) << 16 : 0);
240 }
241 
242 void ext4_block_bitmap_set(struct super_block *sb,
243 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
244 {
245 	bg->bg_block_bitmap_lo = cpu_to_le32((u32)blk);
246 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
247 		bg->bg_block_bitmap_hi = cpu_to_le32(blk >> 32);
248 }
249 
250 void ext4_inode_bitmap_set(struct super_block *sb,
251 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
252 {
253 	bg->bg_inode_bitmap_lo  = cpu_to_le32((u32)blk);
254 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
255 		bg->bg_inode_bitmap_hi = cpu_to_le32(blk >> 32);
256 }
257 
258 void ext4_inode_table_set(struct super_block *sb,
259 			  struct ext4_group_desc *bg, ext4_fsblk_t blk)
260 {
261 	bg->bg_inode_table_lo = cpu_to_le32((u32)blk);
262 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
263 		bg->bg_inode_table_hi = cpu_to_le32(blk >> 32);
264 }
265 
266 void ext4_free_group_clusters_set(struct super_block *sb,
267 				  struct ext4_group_desc *bg, __u32 count)
268 {
269 	bg->bg_free_blocks_count_lo = cpu_to_le16((__u16)count);
270 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
271 		bg->bg_free_blocks_count_hi = cpu_to_le16(count >> 16);
272 }
273 
274 void ext4_free_inodes_set(struct super_block *sb,
275 			  struct ext4_group_desc *bg, __u32 count)
276 {
277 	bg->bg_free_inodes_count_lo = cpu_to_le16((__u16)count);
278 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
279 		bg->bg_free_inodes_count_hi = cpu_to_le16(count >> 16);
280 }
281 
282 void ext4_used_dirs_set(struct super_block *sb,
283 			  struct ext4_group_desc *bg, __u32 count)
284 {
285 	bg->bg_used_dirs_count_lo = cpu_to_le16((__u16)count);
286 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
287 		bg->bg_used_dirs_count_hi = cpu_to_le16(count >> 16);
288 }
289 
290 void ext4_itable_unused_set(struct super_block *sb,
291 			  struct ext4_group_desc *bg, __u32 count)
292 {
293 	bg->bg_itable_unused_lo = cpu_to_le16((__u16)count);
294 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
295 		bg->bg_itable_unused_hi = cpu_to_le16(count >> 16);
296 }
297 
298 
299 /* Just increment the non-pointer handle value */
300 static handle_t *ext4_get_nojournal(void)
301 {
302 	handle_t *handle = current->journal_info;
303 	unsigned long ref_cnt = (unsigned long)handle;
304 
305 	BUG_ON(ref_cnt >= EXT4_NOJOURNAL_MAX_REF_COUNT);
306 
307 	ref_cnt++;
308 	handle = (handle_t *)ref_cnt;
309 
310 	current->journal_info = handle;
311 	return handle;
312 }
313 
314 
315 /* Decrement the non-pointer handle value */
316 static void ext4_put_nojournal(handle_t *handle)
317 {
318 	unsigned long ref_cnt = (unsigned long)handle;
319 
320 	BUG_ON(ref_cnt == 0);
321 
322 	ref_cnt--;
323 	handle = (handle_t *)ref_cnt;
324 
325 	current->journal_info = handle;
326 }
327 
328 /*
329  * Wrappers for jbd2_journal_start/end.
330  *
331  * The only special thing we need to do here is to make sure that all
332  * journal_end calls result in the superblock being marked dirty, so
333  * that sync() will call the filesystem's write_super callback if
334  * appropriate.
335  *
336  * To avoid j_barrier hold in userspace when a user calls freeze(),
337  * ext4 prevents a new handle from being started by s_frozen, which
338  * is in an upper layer.
339  */
340 handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
341 {
342 	journal_t *journal;
343 	handle_t  *handle;
344 
345 	trace_ext4_journal_start(sb, nblocks, _RET_IP_);
346 	if (sb->s_flags & MS_RDONLY)
347 		return ERR_PTR(-EROFS);
348 
349 	journal = EXT4_SB(sb)->s_journal;
350 	handle = ext4_journal_current_handle();
351 
352 	/*
353 	 * If a handle has been started, it should be allowed to
354 	 * finish, otherwise deadlock could happen between freeze
355 	 * and others(e.g. truncate) due to the restart of the
356 	 * journal handle if the filesystem is forzen and active
357 	 * handles are not stopped.
358 	 */
359 	if (!handle)
360 		vfs_check_frozen(sb, SB_FREEZE_TRANS);
361 
362 	if (!journal)
363 		return ext4_get_nojournal();
364 	/*
365 	 * Special case here: if the journal has aborted behind our
366 	 * backs (eg. EIO in the commit thread), then we still need to
367 	 * take the FS itself readonly cleanly.
368 	 */
369 	if (is_journal_aborted(journal)) {
370 		ext4_abort(sb, "Detected aborted journal");
371 		return ERR_PTR(-EROFS);
372 	}
373 	return jbd2_journal_start(journal, nblocks);
374 }
375 
376 /*
377  * The only special thing we need to do here is to make sure that all
378  * jbd2_journal_stop calls result in the superblock being marked dirty, so
379  * that sync() will call the filesystem's write_super callback if
380  * appropriate.
381  */
382 int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle)
383 {
384 	struct super_block *sb;
385 	int err;
386 	int rc;
387 
388 	if (!ext4_handle_valid(handle)) {
389 		ext4_put_nojournal(handle);
390 		return 0;
391 	}
392 	sb = handle->h_transaction->t_journal->j_private;
393 	err = handle->h_err;
394 	rc = jbd2_journal_stop(handle);
395 
396 	if (!err)
397 		err = rc;
398 	if (err)
399 		__ext4_std_error(sb, where, line, err);
400 	return err;
401 }
402 
403 void ext4_journal_abort_handle(const char *caller, unsigned int line,
404 			       const char *err_fn, struct buffer_head *bh,
405 			       handle_t *handle, int err)
406 {
407 	char nbuf[16];
408 	const char *errstr = ext4_decode_error(NULL, err, nbuf);
409 
410 	BUG_ON(!ext4_handle_valid(handle));
411 
412 	if (bh)
413 		BUFFER_TRACE(bh, "abort");
414 
415 	if (!handle->h_err)
416 		handle->h_err = err;
417 
418 	if (is_handle_aborted(handle))
419 		return;
420 
421 	printk(KERN_ERR "EXT4-fs: %s:%d: aborting transaction: %s in %s\n",
422 	       caller, line, errstr, err_fn);
423 
424 	jbd2_journal_abort_handle(handle);
425 }
426 
427 static void __save_error_info(struct super_block *sb, const char *func,
428 			    unsigned int line)
429 {
430 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
431 
432 	EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
433 	es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
434 	es->s_last_error_time = cpu_to_le32(get_seconds());
435 	strncpy(es->s_last_error_func, func, sizeof(es->s_last_error_func));
436 	es->s_last_error_line = cpu_to_le32(line);
437 	if (!es->s_first_error_time) {
438 		es->s_first_error_time = es->s_last_error_time;
439 		strncpy(es->s_first_error_func, func,
440 			sizeof(es->s_first_error_func));
441 		es->s_first_error_line = cpu_to_le32(line);
442 		es->s_first_error_ino = es->s_last_error_ino;
443 		es->s_first_error_block = es->s_last_error_block;
444 	}
445 	/*
446 	 * Start the daily error reporting function if it hasn't been
447 	 * started already
448 	 */
449 	if (!es->s_error_count)
450 		mod_timer(&EXT4_SB(sb)->s_err_report, jiffies + 24*60*60*HZ);
451 	es->s_error_count = cpu_to_le32(le32_to_cpu(es->s_error_count) + 1);
452 }
453 
454 static void save_error_info(struct super_block *sb, const char *func,
455 			    unsigned int line)
456 {
457 	__save_error_info(sb, func, line);
458 	ext4_commit_super(sb, 1);
459 }
460 
461 /*
462  * The del_gendisk() function uninitializes the disk-specific data
463  * structures, including the bdi structure, without telling anyone
464  * else.  Once this happens, any attempt to call mark_buffer_dirty()
465  * (for example, by ext4_commit_super), will cause a kernel OOPS.
466  * This is a kludge to prevent these oops until we can put in a proper
467  * hook in del_gendisk() to inform the VFS and file system layers.
468  */
469 static int block_device_ejected(struct super_block *sb)
470 {
471 	struct inode *bd_inode = sb->s_bdev->bd_inode;
472 	struct backing_dev_info *bdi = bd_inode->i_mapping->backing_dev_info;
473 
474 	return bdi->dev == NULL;
475 }
476 
477 static void ext4_journal_commit_callback(journal_t *journal, transaction_t *txn)
478 {
479 	struct super_block		*sb = journal->j_private;
480 	struct ext4_sb_info		*sbi = EXT4_SB(sb);
481 	int				error = is_journal_aborted(journal);
482 	struct ext4_journal_cb_entry	*jce, *tmp;
483 
484 	spin_lock(&sbi->s_md_lock);
485 	list_for_each_entry_safe(jce, tmp, &txn->t_private_list, jce_list) {
486 		list_del_init(&jce->jce_list);
487 		spin_unlock(&sbi->s_md_lock);
488 		jce->jce_func(sb, jce, error);
489 		spin_lock(&sbi->s_md_lock);
490 	}
491 	spin_unlock(&sbi->s_md_lock);
492 }
493 
494 /* Deal with the reporting of failure conditions on a filesystem such as
495  * inconsistencies detected or read IO failures.
496  *
497  * On ext2, we can store the error state of the filesystem in the
498  * superblock.  That is not possible on ext4, because we may have other
499  * write ordering constraints on the superblock which prevent us from
500  * writing it out straight away; and given that the journal is about to
501  * be aborted, we can't rely on the current, or future, transactions to
502  * write out the superblock safely.
503  *
504  * We'll just use the jbd2_journal_abort() error code to record an error in
505  * the journal instead.  On recovery, the journal will complain about
506  * that error until we've noted it down and cleared it.
507  */
508 
509 static void ext4_handle_error(struct super_block *sb)
510 {
511 	if (sb->s_flags & MS_RDONLY)
512 		return;
513 
514 	if (!test_opt(sb, ERRORS_CONT)) {
515 		journal_t *journal = EXT4_SB(sb)->s_journal;
516 
517 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
518 		if (journal)
519 			jbd2_journal_abort(journal, -EIO);
520 	}
521 	if (test_opt(sb, ERRORS_RO)) {
522 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
523 		sb->s_flags |= MS_RDONLY;
524 	}
525 	if (test_opt(sb, ERRORS_PANIC))
526 		panic("EXT4-fs (device %s): panic forced after error\n",
527 			sb->s_id);
528 }
529 
530 void __ext4_error(struct super_block *sb, const char *function,
531 		  unsigned int line, const char *fmt, ...)
532 {
533 	struct va_format vaf;
534 	va_list args;
535 
536 	va_start(args, fmt);
537 	vaf.fmt = fmt;
538 	vaf.va = &args;
539 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: comm %s: %pV\n",
540 	       sb->s_id, function, line, current->comm, &vaf);
541 	va_end(args);
542 	save_error_info(sb, function, line);
543 
544 	ext4_handle_error(sb);
545 }
546 
547 void ext4_error_inode(struct inode *inode, const char *function,
548 		      unsigned int line, ext4_fsblk_t block,
549 		      const char *fmt, ...)
550 {
551 	va_list args;
552 	struct va_format vaf;
553 	struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
554 
555 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
556 	es->s_last_error_block = cpu_to_le64(block);
557 	save_error_info(inode->i_sb, function, line);
558 	va_start(args, fmt);
559 	vaf.fmt = fmt;
560 	vaf.va = &args;
561 	if (block)
562 		printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
563 		       "inode #%lu: block %llu: comm %s: %pV\n",
564 		       inode->i_sb->s_id, function, line, inode->i_ino,
565 		       block, current->comm, &vaf);
566 	else
567 		printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
568 		       "inode #%lu: comm %s: %pV\n",
569 		       inode->i_sb->s_id, function, line, inode->i_ino,
570 		       current->comm, &vaf);
571 	va_end(args);
572 
573 	ext4_handle_error(inode->i_sb);
574 }
575 
576 void ext4_error_file(struct file *file, const char *function,
577 		     unsigned int line, ext4_fsblk_t block,
578 		     const char *fmt, ...)
579 {
580 	va_list args;
581 	struct va_format vaf;
582 	struct ext4_super_block *es;
583 	struct inode *inode = file->f_dentry->d_inode;
584 	char pathname[80], *path;
585 
586 	es = EXT4_SB(inode->i_sb)->s_es;
587 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
588 	save_error_info(inode->i_sb, function, line);
589 	path = d_path(&(file->f_path), pathname, sizeof(pathname));
590 	if (IS_ERR(path))
591 		path = "(unknown)";
592 	va_start(args, fmt);
593 	vaf.fmt = fmt;
594 	vaf.va = &args;
595 	if (block)
596 		printk(KERN_CRIT
597 		       "EXT4-fs error (device %s): %s:%d: inode #%lu: "
598 		       "block %llu: comm %s: path %s: %pV\n",
599 		       inode->i_sb->s_id, function, line, inode->i_ino,
600 		       block, current->comm, path, &vaf);
601 	else
602 		printk(KERN_CRIT
603 		       "EXT4-fs error (device %s): %s:%d: inode #%lu: "
604 		       "comm %s: path %s: %pV\n",
605 		       inode->i_sb->s_id, function, line, inode->i_ino,
606 		       current->comm, path, &vaf);
607 	va_end(args);
608 
609 	ext4_handle_error(inode->i_sb);
610 }
611 
612 static const char *ext4_decode_error(struct super_block *sb, int errno,
613 				     char nbuf[16])
614 {
615 	char *errstr = NULL;
616 
617 	switch (errno) {
618 	case -EIO:
619 		errstr = "IO failure";
620 		break;
621 	case -ENOMEM:
622 		errstr = "Out of memory";
623 		break;
624 	case -EROFS:
625 		if (!sb || (EXT4_SB(sb)->s_journal &&
626 			    EXT4_SB(sb)->s_journal->j_flags & JBD2_ABORT))
627 			errstr = "Journal has aborted";
628 		else
629 			errstr = "Readonly filesystem";
630 		break;
631 	default:
632 		/* If the caller passed in an extra buffer for unknown
633 		 * errors, textualise them now.  Else we just return
634 		 * NULL. */
635 		if (nbuf) {
636 			/* Check for truncated error codes... */
637 			if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
638 				errstr = nbuf;
639 		}
640 		break;
641 	}
642 
643 	return errstr;
644 }
645 
646 /* __ext4_std_error decodes expected errors from journaling functions
647  * automatically and invokes the appropriate error response.  */
648 
649 void __ext4_std_error(struct super_block *sb, const char *function,
650 		      unsigned int line, int errno)
651 {
652 	char nbuf[16];
653 	const char *errstr;
654 
655 	/* Special case: if the error is EROFS, and we're not already
656 	 * inside a transaction, then there's really no point in logging
657 	 * an error. */
658 	if (errno == -EROFS && journal_current_handle() == NULL &&
659 	    (sb->s_flags & MS_RDONLY))
660 		return;
661 
662 	errstr = ext4_decode_error(sb, errno, nbuf);
663 	printk(KERN_CRIT "EXT4-fs error (device %s) in %s:%d: %s\n",
664 	       sb->s_id, function, line, errstr);
665 	save_error_info(sb, function, line);
666 
667 	ext4_handle_error(sb);
668 }
669 
670 /*
671  * ext4_abort is a much stronger failure handler than ext4_error.  The
672  * abort function may be used to deal with unrecoverable failures such
673  * as journal IO errors or ENOMEM at a critical moment in log management.
674  *
675  * We unconditionally force the filesystem into an ABORT|READONLY state,
676  * unless the error response on the fs has been set to panic in which
677  * case we take the easy way out and panic immediately.
678  */
679 
680 void __ext4_abort(struct super_block *sb, const char *function,
681 		unsigned int line, const char *fmt, ...)
682 {
683 	va_list args;
684 
685 	save_error_info(sb, function, line);
686 	va_start(args, fmt);
687 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: ", sb->s_id,
688 	       function, line);
689 	vprintk(fmt, args);
690 	printk("\n");
691 	va_end(args);
692 
693 	if ((sb->s_flags & MS_RDONLY) == 0) {
694 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
695 		sb->s_flags |= MS_RDONLY;
696 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
697 		if (EXT4_SB(sb)->s_journal)
698 			jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
699 		save_error_info(sb, function, line);
700 	}
701 	if (test_opt(sb, ERRORS_PANIC))
702 		panic("EXT4-fs panic from previous error\n");
703 }
704 
705 void ext4_msg(struct super_block *sb, const char *prefix, const char *fmt, ...)
706 {
707 	struct va_format vaf;
708 	va_list args;
709 
710 	va_start(args, fmt);
711 	vaf.fmt = fmt;
712 	vaf.va = &args;
713 	printk("%sEXT4-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
714 	va_end(args);
715 }
716 
717 void __ext4_warning(struct super_block *sb, const char *function,
718 		    unsigned int line, const char *fmt, ...)
719 {
720 	struct va_format vaf;
721 	va_list args;
722 
723 	va_start(args, fmt);
724 	vaf.fmt = fmt;
725 	vaf.va = &args;
726 	printk(KERN_WARNING "EXT4-fs warning (device %s): %s:%d: %pV\n",
727 	       sb->s_id, function, line, &vaf);
728 	va_end(args);
729 }
730 
731 void __ext4_grp_locked_error(const char *function, unsigned int line,
732 			     struct super_block *sb, ext4_group_t grp,
733 			     unsigned long ino, ext4_fsblk_t block,
734 			     const char *fmt, ...)
735 __releases(bitlock)
736 __acquires(bitlock)
737 {
738 	struct va_format vaf;
739 	va_list args;
740 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
741 
742 	es->s_last_error_ino = cpu_to_le32(ino);
743 	es->s_last_error_block = cpu_to_le64(block);
744 	__save_error_info(sb, function, line);
745 
746 	va_start(args, fmt);
747 
748 	vaf.fmt = fmt;
749 	vaf.va = &args;
750 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: group %u, ",
751 	       sb->s_id, function, line, grp);
752 	if (ino)
753 		printk(KERN_CONT "inode %lu: ", ino);
754 	if (block)
755 		printk(KERN_CONT "block %llu:", (unsigned long long) block);
756 	printk(KERN_CONT "%pV\n", &vaf);
757 	va_end(args);
758 
759 	if (test_opt(sb, ERRORS_CONT)) {
760 		ext4_commit_super(sb, 0);
761 		return;
762 	}
763 
764 	ext4_unlock_group(sb, grp);
765 	ext4_handle_error(sb);
766 	/*
767 	 * We only get here in the ERRORS_RO case; relocking the group
768 	 * may be dangerous, but nothing bad will happen since the
769 	 * filesystem will have already been marked read/only and the
770 	 * journal has been aborted.  We return 1 as a hint to callers
771 	 * who might what to use the return value from
772 	 * ext4_grp_locked_error() to distinguish between the
773 	 * ERRORS_CONT and ERRORS_RO case, and perhaps return more
774 	 * aggressively from the ext4 function in question, with a
775 	 * more appropriate error code.
776 	 */
777 	ext4_lock_group(sb, grp);
778 	return;
779 }
780 
781 void ext4_update_dynamic_rev(struct super_block *sb)
782 {
783 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
784 
785 	if (le32_to_cpu(es->s_rev_level) > EXT4_GOOD_OLD_REV)
786 		return;
787 
788 	ext4_warning(sb,
789 		     "updating to rev %d because of new feature flag, "
790 		     "running e2fsck is recommended",
791 		     EXT4_DYNAMIC_REV);
792 
793 	es->s_first_ino = cpu_to_le32(EXT4_GOOD_OLD_FIRST_INO);
794 	es->s_inode_size = cpu_to_le16(EXT4_GOOD_OLD_INODE_SIZE);
795 	es->s_rev_level = cpu_to_le32(EXT4_DYNAMIC_REV);
796 	/* leave es->s_feature_*compat flags alone */
797 	/* es->s_uuid will be set by e2fsck if empty */
798 
799 	/*
800 	 * The rest of the superblock fields should be zero, and if not it
801 	 * means they are likely already in use, so leave them alone.  We
802 	 * can leave it up to e2fsck to clean up any inconsistencies there.
803 	 */
804 }
805 
806 /*
807  * Open the external journal device
808  */
809 static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb)
810 {
811 	struct block_device *bdev;
812 	char b[BDEVNAME_SIZE];
813 
814 	bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb);
815 	if (IS_ERR(bdev))
816 		goto fail;
817 	return bdev;
818 
819 fail:
820 	ext4_msg(sb, KERN_ERR, "failed to open journal device %s: %ld",
821 			__bdevname(dev, b), PTR_ERR(bdev));
822 	return NULL;
823 }
824 
825 /*
826  * Release the journal device
827  */
828 static int ext4_blkdev_put(struct block_device *bdev)
829 {
830 	return blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
831 }
832 
833 static int ext4_blkdev_remove(struct ext4_sb_info *sbi)
834 {
835 	struct block_device *bdev;
836 	int ret = -ENODEV;
837 
838 	bdev = sbi->journal_bdev;
839 	if (bdev) {
840 		ret = ext4_blkdev_put(bdev);
841 		sbi->journal_bdev = NULL;
842 	}
843 	return ret;
844 }
845 
846 static inline struct inode *orphan_list_entry(struct list_head *l)
847 {
848 	return &list_entry(l, struct ext4_inode_info, i_orphan)->vfs_inode;
849 }
850 
851 static void dump_orphan_list(struct super_block *sb, struct ext4_sb_info *sbi)
852 {
853 	struct list_head *l;
854 
855 	ext4_msg(sb, KERN_ERR, "sb orphan head is %d",
856 		 le32_to_cpu(sbi->s_es->s_last_orphan));
857 
858 	printk(KERN_ERR "sb_info orphan list:\n");
859 	list_for_each(l, &sbi->s_orphan) {
860 		struct inode *inode = orphan_list_entry(l);
861 		printk(KERN_ERR "  "
862 		       "inode %s:%lu at %p: mode %o, nlink %d, next %d\n",
863 		       inode->i_sb->s_id, inode->i_ino, inode,
864 		       inode->i_mode, inode->i_nlink,
865 		       NEXT_ORPHAN(inode));
866 	}
867 }
868 
869 static void ext4_put_super(struct super_block *sb)
870 {
871 	struct ext4_sb_info *sbi = EXT4_SB(sb);
872 	struct ext4_super_block *es = sbi->s_es;
873 	int i, err;
874 
875 	ext4_unregister_li_request(sb);
876 	dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
877 
878 	flush_workqueue(sbi->dio_unwritten_wq);
879 	destroy_workqueue(sbi->dio_unwritten_wq);
880 
881 	lock_super(sb);
882 	if (sbi->s_journal) {
883 		err = jbd2_journal_destroy(sbi->s_journal);
884 		sbi->s_journal = NULL;
885 		if (err < 0)
886 			ext4_abort(sb, "Couldn't clean up the journal");
887 	}
888 
889 	del_timer(&sbi->s_err_report);
890 	ext4_release_system_zone(sb);
891 	ext4_mb_release(sb);
892 	ext4_ext_release(sb);
893 	ext4_xattr_put_super(sb);
894 
895 	if (!(sb->s_flags & MS_RDONLY)) {
896 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
897 		es->s_state = cpu_to_le16(sbi->s_mount_state);
898 	}
899 	if (sb->s_dirt || !(sb->s_flags & MS_RDONLY))
900 		ext4_commit_super(sb, 1);
901 
902 	if (sbi->s_proc) {
903 		remove_proc_entry("options", sbi->s_proc);
904 		remove_proc_entry(sb->s_id, ext4_proc_root);
905 	}
906 	kobject_del(&sbi->s_kobj);
907 
908 	for (i = 0; i < sbi->s_gdb_count; i++)
909 		brelse(sbi->s_group_desc[i]);
910 	ext4_kvfree(sbi->s_group_desc);
911 	ext4_kvfree(sbi->s_flex_groups);
912 	percpu_counter_destroy(&sbi->s_freeclusters_counter);
913 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
914 	percpu_counter_destroy(&sbi->s_dirs_counter);
915 	percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
916 	brelse(sbi->s_sbh);
917 #ifdef CONFIG_QUOTA
918 	for (i = 0; i < MAXQUOTAS; i++)
919 		kfree(sbi->s_qf_names[i]);
920 #endif
921 
922 	/* Debugging code just in case the in-memory inode orphan list
923 	 * isn't empty.  The on-disk one can be non-empty if we've
924 	 * detected an error and taken the fs readonly, but the
925 	 * in-memory list had better be clean by this point. */
926 	if (!list_empty(&sbi->s_orphan))
927 		dump_orphan_list(sb, sbi);
928 	J_ASSERT(list_empty(&sbi->s_orphan));
929 
930 	invalidate_bdev(sb->s_bdev);
931 	if (sbi->journal_bdev && sbi->journal_bdev != sb->s_bdev) {
932 		/*
933 		 * Invalidate the journal device's buffers.  We don't want them
934 		 * floating about in memory - the physical journal device may
935 		 * hotswapped, and it breaks the `ro-after' testing code.
936 		 */
937 		sync_blockdev(sbi->journal_bdev);
938 		invalidate_bdev(sbi->journal_bdev);
939 		ext4_blkdev_remove(sbi);
940 	}
941 	if (sbi->s_mmp_tsk)
942 		kthread_stop(sbi->s_mmp_tsk);
943 	sb->s_fs_info = NULL;
944 	/*
945 	 * Now that we are completely done shutting down the
946 	 * superblock, we need to actually destroy the kobject.
947 	 */
948 	unlock_super(sb);
949 	kobject_put(&sbi->s_kobj);
950 	wait_for_completion(&sbi->s_kobj_unregister);
951 	if (sbi->s_chksum_driver)
952 		crypto_free_shash(sbi->s_chksum_driver);
953 	kfree(sbi->s_blockgroup_lock);
954 	kfree(sbi);
955 }
956 
957 static struct kmem_cache *ext4_inode_cachep;
958 
959 /*
960  * Called inside transaction, so use GFP_NOFS
961  */
962 static struct inode *ext4_alloc_inode(struct super_block *sb)
963 {
964 	struct ext4_inode_info *ei;
965 
966 	ei = kmem_cache_alloc(ext4_inode_cachep, GFP_NOFS);
967 	if (!ei)
968 		return NULL;
969 
970 	ei->vfs_inode.i_version = 1;
971 	ei->vfs_inode.i_data.writeback_index = 0;
972 	memset(&ei->i_cached_extent, 0, sizeof(struct ext4_ext_cache));
973 	INIT_LIST_HEAD(&ei->i_prealloc_list);
974 	spin_lock_init(&ei->i_prealloc_lock);
975 	ei->i_reserved_data_blocks = 0;
976 	ei->i_reserved_meta_blocks = 0;
977 	ei->i_allocated_meta_blocks = 0;
978 	ei->i_da_metadata_calc_len = 0;
979 	spin_lock_init(&(ei->i_block_reservation_lock));
980 #ifdef CONFIG_QUOTA
981 	ei->i_reserved_quota = 0;
982 #endif
983 	ei->jinode = NULL;
984 	INIT_LIST_HEAD(&ei->i_completed_io_list);
985 	spin_lock_init(&ei->i_completed_io_lock);
986 	ei->cur_aio_dio = NULL;
987 	ei->i_sync_tid = 0;
988 	ei->i_datasync_tid = 0;
989 	atomic_set(&ei->i_ioend_count, 0);
990 	atomic_set(&ei->i_aiodio_unwritten, 0);
991 
992 	return &ei->vfs_inode;
993 }
994 
995 static int ext4_drop_inode(struct inode *inode)
996 {
997 	int drop = generic_drop_inode(inode);
998 
999 	trace_ext4_drop_inode(inode, drop);
1000 	return drop;
1001 }
1002 
1003 static void ext4_i_callback(struct rcu_head *head)
1004 {
1005 	struct inode *inode = container_of(head, struct inode, i_rcu);
1006 	kmem_cache_free(ext4_inode_cachep, EXT4_I(inode));
1007 }
1008 
1009 static void ext4_destroy_inode(struct inode *inode)
1010 {
1011 	if (!list_empty(&(EXT4_I(inode)->i_orphan))) {
1012 		ext4_msg(inode->i_sb, KERN_ERR,
1013 			 "Inode %lu (%p): orphan list check failed!",
1014 			 inode->i_ino, EXT4_I(inode));
1015 		print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 16, 4,
1016 				EXT4_I(inode), sizeof(struct ext4_inode_info),
1017 				true);
1018 		dump_stack();
1019 	}
1020 	call_rcu(&inode->i_rcu, ext4_i_callback);
1021 }
1022 
1023 static void init_once(void *foo)
1024 {
1025 	struct ext4_inode_info *ei = (struct ext4_inode_info *) foo;
1026 
1027 	INIT_LIST_HEAD(&ei->i_orphan);
1028 #ifdef CONFIG_EXT4_FS_XATTR
1029 	init_rwsem(&ei->xattr_sem);
1030 #endif
1031 	init_rwsem(&ei->i_data_sem);
1032 	inode_init_once(&ei->vfs_inode);
1033 }
1034 
1035 static int init_inodecache(void)
1036 {
1037 	ext4_inode_cachep = kmem_cache_create("ext4_inode_cache",
1038 					     sizeof(struct ext4_inode_info),
1039 					     0, (SLAB_RECLAIM_ACCOUNT|
1040 						SLAB_MEM_SPREAD),
1041 					     init_once);
1042 	if (ext4_inode_cachep == NULL)
1043 		return -ENOMEM;
1044 	return 0;
1045 }
1046 
1047 static void destroy_inodecache(void)
1048 {
1049 	kmem_cache_destroy(ext4_inode_cachep);
1050 }
1051 
1052 void ext4_clear_inode(struct inode *inode)
1053 {
1054 	invalidate_inode_buffers(inode);
1055 	clear_inode(inode);
1056 	dquot_drop(inode);
1057 	ext4_discard_preallocations(inode);
1058 	if (EXT4_I(inode)->jinode) {
1059 		jbd2_journal_release_jbd_inode(EXT4_JOURNAL(inode),
1060 					       EXT4_I(inode)->jinode);
1061 		jbd2_free_inode(EXT4_I(inode)->jinode);
1062 		EXT4_I(inode)->jinode = NULL;
1063 	}
1064 }
1065 
1066 static struct inode *ext4_nfs_get_inode(struct super_block *sb,
1067 					u64 ino, u32 generation)
1068 {
1069 	struct inode *inode;
1070 
1071 	if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
1072 		return ERR_PTR(-ESTALE);
1073 	if (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
1074 		return ERR_PTR(-ESTALE);
1075 
1076 	/* iget isn't really right if the inode is currently unallocated!!
1077 	 *
1078 	 * ext4_read_inode will return a bad_inode if the inode had been
1079 	 * deleted, so we should be safe.
1080 	 *
1081 	 * Currently we don't know the generation for parent directory, so
1082 	 * a generation of 0 means "accept any"
1083 	 */
1084 	inode = ext4_iget(sb, ino);
1085 	if (IS_ERR(inode))
1086 		return ERR_CAST(inode);
1087 	if (generation && inode->i_generation != generation) {
1088 		iput(inode);
1089 		return ERR_PTR(-ESTALE);
1090 	}
1091 
1092 	return inode;
1093 }
1094 
1095 static struct dentry *ext4_fh_to_dentry(struct super_block *sb, struct fid *fid,
1096 					int fh_len, int fh_type)
1097 {
1098 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
1099 				    ext4_nfs_get_inode);
1100 }
1101 
1102 static struct dentry *ext4_fh_to_parent(struct super_block *sb, struct fid *fid,
1103 					int fh_len, int fh_type)
1104 {
1105 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
1106 				    ext4_nfs_get_inode);
1107 }
1108 
1109 /*
1110  * Try to release metadata pages (indirect blocks, directories) which are
1111  * mapped via the block device.  Since these pages could have journal heads
1112  * which would prevent try_to_free_buffers() from freeing them, we must use
1113  * jbd2 layer's try_to_free_buffers() function to release them.
1114  */
1115 static int bdev_try_to_free_page(struct super_block *sb, struct page *page,
1116 				 gfp_t wait)
1117 {
1118 	journal_t *journal = EXT4_SB(sb)->s_journal;
1119 
1120 	WARN_ON(PageChecked(page));
1121 	if (!page_has_buffers(page))
1122 		return 0;
1123 	if (journal)
1124 		return jbd2_journal_try_to_free_buffers(journal, page,
1125 							wait & ~__GFP_WAIT);
1126 	return try_to_free_buffers(page);
1127 }
1128 
1129 #ifdef CONFIG_QUOTA
1130 #define QTYPE2NAME(t) ((t) == USRQUOTA ? "user" : "group")
1131 #define QTYPE2MOPT(on, t) ((t) == USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
1132 
1133 static int ext4_write_dquot(struct dquot *dquot);
1134 static int ext4_acquire_dquot(struct dquot *dquot);
1135 static int ext4_release_dquot(struct dquot *dquot);
1136 static int ext4_mark_dquot_dirty(struct dquot *dquot);
1137 static int ext4_write_info(struct super_block *sb, int type);
1138 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
1139 			 struct path *path);
1140 static int ext4_quota_off(struct super_block *sb, int type);
1141 static int ext4_quota_on_mount(struct super_block *sb, int type);
1142 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
1143 			       size_t len, loff_t off);
1144 static ssize_t ext4_quota_write(struct super_block *sb, int type,
1145 				const char *data, size_t len, loff_t off);
1146 
1147 static const struct dquot_operations ext4_quota_operations = {
1148 	.get_reserved_space = ext4_get_reserved_space,
1149 	.write_dquot	= ext4_write_dquot,
1150 	.acquire_dquot	= ext4_acquire_dquot,
1151 	.release_dquot	= ext4_release_dquot,
1152 	.mark_dirty	= ext4_mark_dquot_dirty,
1153 	.write_info	= ext4_write_info,
1154 	.alloc_dquot	= dquot_alloc,
1155 	.destroy_dquot	= dquot_destroy,
1156 };
1157 
1158 static const struct quotactl_ops ext4_qctl_operations = {
1159 	.quota_on	= ext4_quota_on,
1160 	.quota_off	= ext4_quota_off,
1161 	.quota_sync	= dquot_quota_sync,
1162 	.get_info	= dquot_get_dqinfo,
1163 	.set_info	= dquot_set_dqinfo,
1164 	.get_dqblk	= dquot_get_dqblk,
1165 	.set_dqblk	= dquot_set_dqblk
1166 };
1167 #endif
1168 
1169 static const struct super_operations ext4_sops = {
1170 	.alloc_inode	= ext4_alloc_inode,
1171 	.destroy_inode	= ext4_destroy_inode,
1172 	.write_inode	= ext4_write_inode,
1173 	.dirty_inode	= ext4_dirty_inode,
1174 	.drop_inode	= ext4_drop_inode,
1175 	.evict_inode	= ext4_evict_inode,
1176 	.put_super	= ext4_put_super,
1177 	.sync_fs	= ext4_sync_fs,
1178 	.freeze_fs	= ext4_freeze,
1179 	.unfreeze_fs	= ext4_unfreeze,
1180 	.statfs		= ext4_statfs,
1181 	.remount_fs	= ext4_remount,
1182 	.show_options	= ext4_show_options,
1183 #ifdef CONFIG_QUOTA
1184 	.quota_read	= ext4_quota_read,
1185 	.quota_write	= ext4_quota_write,
1186 #endif
1187 	.bdev_try_to_free_page = bdev_try_to_free_page,
1188 };
1189 
1190 static const struct super_operations ext4_nojournal_sops = {
1191 	.alloc_inode	= ext4_alloc_inode,
1192 	.destroy_inode	= ext4_destroy_inode,
1193 	.write_inode	= ext4_write_inode,
1194 	.dirty_inode	= ext4_dirty_inode,
1195 	.drop_inode	= ext4_drop_inode,
1196 	.evict_inode	= ext4_evict_inode,
1197 	.write_super	= ext4_write_super,
1198 	.put_super	= ext4_put_super,
1199 	.statfs		= ext4_statfs,
1200 	.remount_fs	= ext4_remount,
1201 	.show_options	= ext4_show_options,
1202 #ifdef CONFIG_QUOTA
1203 	.quota_read	= ext4_quota_read,
1204 	.quota_write	= ext4_quota_write,
1205 #endif
1206 	.bdev_try_to_free_page = bdev_try_to_free_page,
1207 };
1208 
1209 static const struct export_operations ext4_export_ops = {
1210 	.fh_to_dentry = ext4_fh_to_dentry,
1211 	.fh_to_parent = ext4_fh_to_parent,
1212 	.get_parent = ext4_get_parent,
1213 };
1214 
1215 enum {
1216 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
1217 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
1218 	Opt_nouid32, Opt_debug, Opt_removed,
1219 	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
1220 	Opt_auto_da_alloc, Opt_noauto_da_alloc, Opt_noload,
1221 	Opt_commit, Opt_min_batch_time, Opt_max_batch_time,
1222 	Opt_journal_dev, Opt_journal_checksum, Opt_journal_async_commit,
1223 	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
1224 	Opt_data_err_abort, Opt_data_err_ignore,
1225 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
1226 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
1227 	Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err,
1228 	Opt_usrquota, Opt_grpquota, Opt_i_version,
1229 	Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_mblk_io_submit,
1230 	Opt_nomblk_io_submit, Opt_block_validity, Opt_noblock_validity,
1231 	Opt_inode_readahead_blks, Opt_journal_ioprio,
1232 	Opt_dioread_nolock, Opt_dioread_lock,
1233 	Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
1234 };
1235 
1236 static const match_table_t tokens = {
1237 	{Opt_bsd_df, "bsddf"},
1238 	{Opt_minix_df, "minixdf"},
1239 	{Opt_grpid, "grpid"},
1240 	{Opt_grpid, "bsdgroups"},
1241 	{Opt_nogrpid, "nogrpid"},
1242 	{Opt_nogrpid, "sysvgroups"},
1243 	{Opt_resgid, "resgid=%u"},
1244 	{Opt_resuid, "resuid=%u"},
1245 	{Opt_sb, "sb=%u"},
1246 	{Opt_err_cont, "errors=continue"},
1247 	{Opt_err_panic, "errors=panic"},
1248 	{Opt_err_ro, "errors=remount-ro"},
1249 	{Opt_nouid32, "nouid32"},
1250 	{Opt_debug, "debug"},
1251 	{Opt_removed, "oldalloc"},
1252 	{Opt_removed, "orlov"},
1253 	{Opt_user_xattr, "user_xattr"},
1254 	{Opt_nouser_xattr, "nouser_xattr"},
1255 	{Opt_acl, "acl"},
1256 	{Opt_noacl, "noacl"},
1257 	{Opt_noload, "norecovery"},
1258 	{Opt_noload, "noload"},
1259 	{Opt_removed, "nobh"},
1260 	{Opt_removed, "bh"},
1261 	{Opt_commit, "commit=%u"},
1262 	{Opt_min_batch_time, "min_batch_time=%u"},
1263 	{Opt_max_batch_time, "max_batch_time=%u"},
1264 	{Opt_journal_dev, "journal_dev=%u"},
1265 	{Opt_journal_checksum, "journal_checksum"},
1266 	{Opt_journal_async_commit, "journal_async_commit"},
1267 	{Opt_abort, "abort"},
1268 	{Opt_data_journal, "data=journal"},
1269 	{Opt_data_ordered, "data=ordered"},
1270 	{Opt_data_writeback, "data=writeback"},
1271 	{Opt_data_err_abort, "data_err=abort"},
1272 	{Opt_data_err_ignore, "data_err=ignore"},
1273 	{Opt_offusrjquota, "usrjquota="},
1274 	{Opt_usrjquota, "usrjquota=%s"},
1275 	{Opt_offgrpjquota, "grpjquota="},
1276 	{Opt_grpjquota, "grpjquota=%s"},
1277 	{Opt_jqfmt_vfsold, "jqfmt=vfsold"},
1278 	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
1279 	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
1280 	{Opt_grpquota, "grpquota"},
1281 	{Opt_noquota, "noquota"},
1282 	{Opt_quota, "quota"},
1283 	{Opt_usrquota, "usrquota"},
1284 	{Opt_barrier, "barrier=%u"},
1285 	{Opt_barrier, "barrier"},
1286 	{Opt_nobarrier, "nobarrier"},
1287 	{Opt_i_version, "i_version"},
1288 	{Opt_stripe, "stripe=%u"},
1289 	{Opt_delalloc, "delalloc"},
1290 	{Opt_nodelalloc, "nodelalloc"},
1291 	{Opt_mblk_io_submit, "mblk_io_submit"},
1292 	{Opt_nomblk_io_submit, "nomblk_io_submit"},
1293 	{Opt_block_validity, "block_validity"},
1294 	{Opt_noblock_validity, "noblock_validity"},
1295 	{Opt_inode_readahead_blks, "inode_readahead_blks=%u"},
1296 	{Opt_journal_ioprio, "journal_ioprio=%u"},
1297 	{Opt_auto_da_alloc, "auto_da_alloc=%u"},
1298 	{Opt_auto_da_alloc, "auto_da_alloc"},
1299 	{Opt_noauto_da_alloc, "noauto_da_alloc"},
1300 	{Opt_dioread_nolock, "dioread_nolock"},
1301 	{Opt_dioread_lock, "dioread_lock"},
1302 	{Opt_discard, "discard"},
1303 	{Opt_nodiscard, "nodiscard"},
1304 	{Opt_init_itable, "init_itable=%u"},
1305 	{Opt_init_itable, "init_itable"},
1306 	{Opt_noinit_itable, "noinit_itable"},
1307 	{Opt_removed, "check=none"},	/* mount option from ext2/3 */
1308 	{Opt_removed, "nocheck"},	/* mount option from ext2/3 */
1309 	{Opt_removed, "reservation"},	/* mount option from ext2/3 */
1310 	{Opt_removed, "noreservation"}, /* mount option from ext2/3 */
1311 	{Opt_removed, "journal=%u"},	/* mount option from ext2/3 */
1312 	{Opt_err, NULL},
1313 };
1314 
1315 static ext4_fsblk_t get_sb_block(void **data)
1316 {
1317 	ext4_fsblk_t	sb_block;
1318 	char		*options = (char *) *data;
1319 
1320 	if (!options || strncmp(options, "sb=", 3) != 0)
1321 		return 1;	/* Default location */
1322 
1323 	options += 3;
1324 	/* TODO: use simple_strtoll with >32bit ext4 */
1325 	sb_block = simple_strtoul(options, &options, 0);
1326 	if (*options && *options != ',') {
1327 		printk(KERN_ERR "EXT4-fs: Invalid sb specification: %s\n",
1328 		       (char *) *data);
1329 		return 1;
1330 	}
1331 	if (*options == ',')
1332 		options++;
1333 	*data = (void *) options;
1334 
1335 	return sb_block;
1336 }
1337 
1338 #define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))
1339 static char deprecated_msg[] = "Mount option \"%s\" will be removed by %s\n"
1340 	"Contact linux-ext4@vger.kernel.org if you think we should keep it.\n";
1341 
1342 #ifdef CONFIG_QUOTA
1343 static int set_qf_name(struct super_block *sb, int qtype, substring_t *args)
1344 {
1345 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1346 	char *qname;
1347 
1348 	if (sb_any_quota_loaded(sb) &&
1349 		!sbi->s_qf_names[qtype]) {
1350 		ext4_msg(sb, KERN_ERR,
1351 			"Cannot change journaled "
1352 			"quota options when quota turned on");
1353 		return -1;
1354 	}
1355 	qname = match_strdup(args);
1356 	if (!qname) {
1357 		ext4_msg(sb, KERN_ERR,
1358 			"Not enough memory for storing quotafile name");
1359 		return -1;
1360 	}
1361 	if (sbi->s_qf_names[qtype] &&
1362 		strcmp(sbi->s_qf_names[qtype], qname)) {
1363 		ext4_msg(sb, KERN_ERR,
1364 			"%s quota file already specified", QTYPE2NAME(qtype));
1365 		kfree(qname);
1366 		return -1;
1367 	}
1368 	sbi->s_qf_names[qtype] = qname;
1369 	if (strchr(sbi->s_qf_names[qtype], '/')) {
1370 		ext4_msg(sb, KERN_ERR,
1371 			"quotafile must be on filesystem root");
1372 		kfree(sbi->s_qf_names[qtype]);
1373 		sbi->s_qf_names[qtype] = NULL;
1374 		return -1;
1375 	}
1376 	set_opt(sb, QUOTA);
1377 	return 1;
1378 }
1379 
1380 static int clear_qf_name(struct super_block *sb, int qtype)
1381 {
1382 
1383 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1384 
1385 	if (sb_any_quota_loaded(sb) &&
1386 		sbi->s_qf_names[qtype]) {
1387 		ext4_msg(sb, KERN_ERR, "Cannot change journaled quota options"
1388 			" when quota turned on");
1389 		return -1;
1390 	}
1391 	/*
1392 	 * The space will be released later when all options are confirmed
1393 	 * to be correct
1394 	 */
1395 	sbi->s_qf_names[qtype] = NULL;
1396 	return 1;
1397 }
1398 #endif
1399 
1400 #define MOPT_SET	0x0001
1401 #define MOPT_CLEAR	0x0002
1402 #define MOPT_NOSUPPORT	0x0004
1403 #define MOPT_EXPLICIT	0x0008
1404 #define MOPT_CLEAR_ERR	0x0010
1405 #define MOPT_GTE0	0x0020
1406 #ifdef CONFIG_QUOTA
1407 #define MOPT_Q		0
1408 #define MOPT_QFMT	0x0040
1409 #else
1410 #define MOPT_Q		MOPT_NOSUPPORT
1411 #define MOPT_QFMT	MOPT_NOSUPPORT
1412 #endif
1413 #define MOPT_DATAJ	0x0080
1414 
1415 static const struct mount_opts {
1416 	int	token;
1417 	int	mount_opt;
1418 	int	flags;
1419 } ext4_mount_opts[] = {
1420 	{Opt_minix_df, EXT4_MOUNT_MINIX_DF, MOPT_SET},
1421 	{Opt_bsd_df, EXT4_MOUNT_MINIX_DF, MOPT_CLEAR},
1422 	{Opt_grpid, EXT4_MOUNT_GRPID, MOPT_SET},
1423 	{Opt_nogrpid, EXT4_MOUNT_GRPID, MOPT_CLEAR},
1424 	{Opt_mblk_io_submit, EXT4_MOUNT_MBLK_IO_SUBMIT, MOPT_SET},
1425 	{Opt_nomblk_io_submit, EXT4_MOUNT_MBLK_IO_SUBMIT, MOPT_CLEAR},
1426 	{Opt_block_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_SET},
1427 	{Opt_noblock_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_CLEAR},
1428 	{Opt_dioread_nolock, EXT4_MOUNT_DIOREAD_NOLOCK, MOPT_SET},
1429 	{Opt_dioread_lock, EXT4_MOUNT_DIOREAD_NOLOCK, MOPT_CLEAR},
1430 	{Opt_discard, EXT4_MOUNT_DISCARD, MOPT_SET},
1431 	{Opt_nodiscard, EXT4_MOUNT_DISCARD, MOPT_CLEAR},
1432 	{Opt_delalloc, EXT4_MOUNT_DELALLOC, MOPT_SET | MOPT_EXPLICIT},
1433 	{Opt_nodelalloc, EXT4_MOUNT_DELALLOC, MOPT_CLEAR | MOPT_EXPLICIT},
1434 	{Opt_journal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM, MOPT_SET},
1435 	{Opt_journal_async_commit, (EXT4_MOUNT_JOURNAL_ASYNC_COMMIT |
1436 				    EXT4_MOUNT_JOURNAL_CHECKSUM), MOPT_SET},
1437 	{Opt_noload, EXT4_MOUNT_NOLOAD, MOPT_SET},
1438 	{Opt_err_panic, EXT4_MOUNT_ERRORS_PANIC, MOPT_SET | MOPT_CLEAR_ERR},
1439 	{Opt_err_ro, EXT4_MOUNT_ERRORS_RO, MOPT_SET | MOPT_CLEAR_ERR},
1440 	{Opt_err_cont, EXT4_MOUNT_ERRORS_CONT, MOPT_SET | MOPT_CLEAR_ERR},
1441 	{Opt_data_err_abort, EXT4_MOUNT_DATA_ERR_ABORT, MOPT_SET},
1442 	{Opt_data_err_ignore, EXT4_MOUNT_DATA_ERR_ABORT, MOPT_CLEAR},
1443 	{Opt_barrier, EXT4_MOUNT_BARRIER, MOPT_SET},
1444 	{Opt_nobarrier, EXT4_MOUNT_BARRIER, MOPT_CLEAR},
1445 	{Opt_noauto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_SET},
1446 	{Opt_auto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_CLEAR},
1447 	{Opt_noinit_itable, EXT4_MOUNT_INIT_INODE_TABLE, MOPT_CLEAR},
1448 	{Opt_commit, 0, MOPT_GTE0},
1449 	{Opt_max_batch_time, 0, MOPT_GTE0},
1450 	{Opt_min_batch_time, 0, MOPT_GTE0},
1451 	{Opt_inode_readahead_blks, 0, MOPT_GTE0},
1452 	{Opt_init_itable, 0, MOPT_GTE0},
1453 	{Opt_stripe, 0, MOPT_GTE0},
1454 	{Opt_data_journal, EXT4_MOUNT_JOURNAL_DATA, MOPT_DATAJ},
1455 	{Opt_data_ordered, EXT4_MOUNT_ORDERED_DATA, MOPT_DATAJ},
1456 	{Opt_data_writeback, EXT4_MOUNT_WRITEBACK_DATA, MOPT_DATAJ},
1457 #ifdef CONFIG_EXT4_FS_XATTR
1458 	{Opt_user_xattr, EXT4_MOUNT_XATTR_USER, MOPT_SET},
1459 	{Opt_nouser_xattr, EXT4_MOUNT_XATTR_USER, MOPT_CLEAR},
1460 #else
1461 	{Opt_user_xattr, 0, MOPT_NOSUPPORT},
1462 	{Opt_nouser_xattr, 0, MOPT_NOSUPPORT},
1463 #endif
1464 #ifdef CONFIG_EXT4_FS_POSIX_ACL
1465 	{Opt_acl, EXT4_MOUNT_POSIX_ACL, MOPT_SET},
1466 	{Opt_noacl, EXT4_MOUNT_POSIX_ACL, MOPT_CLEAR},
1467 #else
1468 	{Opt_acl, 0, MOPT_NOSUPPORT},
1469 	{Opt_noacl, 0, MOPT_NOSUPPORT},
1470 #endif
1471 	{Opt_nouid32, EXT4_MOUNT_NO_UID32, MOPT_SET},
1472 	{Opt_debug, EXT4_MOUNT_DEBUG, MOPT_SET},
1473 	{Opt_quota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA, MOPT_SET | MOPT_Q},
1474 	{Opt_usrquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA,
1475 							MOPT_SET | MOPT_Q},
1476 	{Opt_grpquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_GRPQUOTA,
1477 							MOPT_SET | MOPT_Q},
1478 	{Opt_noquota, (EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA |
1479 		       EXT4_MOUNT_GRPQUOTA), MOPT_CLEAR | MOPT_Q},
1480 	{Opt_usrjquota, 0, MOPT_Q},
1481 	{Opt_grpjquota, 0, MOPT_Q},
1482 	{Opt_offusrjquota, 0, MOPT_Q},
1483 	{Opt_offgrpjquota, 0, MOPT_Q},
1484 	{Opt_jqfmt_vfsold, QFMT_VFS_OLD, MOPT_QFMT},
1485 	{Opt_jqfmt_vfsv0, QFMT_VFS_V0, MOPT_QFMT},
1486 	{Opt_jqfmt_vfsv1, QFMT_VFS_V1, MOPT_QFMT},
1487 	{Opt_err, 0, 0}
1488 };
1489 
1490 static int handle_mount_opt(struct super_block *sb, char *opt, int token,
1491 			    substring_t *args, unsigned long *journal_devnum,
1492 			    unsigned int *journal_ioprio, int is_remount)
1493 {
1494 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1495 	const struct mount_opts *m;
1496 	kuid_t uid;
1497 	kgid_t gid;
1498 	int arg = 0;
1499 
1500 #ifdef CONFIG_QUOTA
1501 	if (token == Opt_usrjquota)
1502 		return set_qf_name(sb, USRQUOTA, &args[0]);
1503 	else if (token == Opt_grpjquota)
1504 		return set_qf_name(sb, GRPQUOTA, &args[0]);
1505 	else if (token == Opt_offusrjquota)
1506 		return clear_qf_name(sb, USRQUOTA);
1507 	else if (token == Opt_offgrpjquota)
1508 		return clear_qf_name(sb, GRPQUOTA);
1509 #endif
1510 	if (args->from && match_int(args, &arg))
1511 		return -1;
1512 	switch (token) {
1513 	case Opt_noacl:
1514 	case Opt_nouser_xattr:
1515 		ext4_msg(sb, KERN_WARNING, deprecated_msg, opt, "3.5");
1516 		break;
1517 	case Opt_sb:
1518 		return 1;	/* handled by get_sb_block() */
1519 	case Opt_removed:
1520 		ext4_msg(sb, KERN_WARNING,
1521 			 "Ignoring removed %s option", opt);
1522 		return 1;
1523 	case Opt_resuid:
1524 		uid = make_kuid(current_user_ns(), arg);
1525 		if (!uid_valid(uid)) {
1526 			ext4_msg(sb, KERN_ERR, "Invalid uid value %d", arg);
1527 			return -1;
1528 		}
1529 		sbi->s_resuid = uid;
1530 		return 1;
1531 	case Opt_resgid:
1532 		gid = make_kgid(current_user_ns(), arg);
1533 		if (!gid_valid(gid)) {
1534 			ext4_msg(sb, KERN_ERR, "Invalid gid value %d", arg);
1535 			return -1;
1536 		}
1537 		sbi->s_resgid = gid;
1538 		return 1;
1539 	case Opt_abort:
1540 		sbi->s_mount_flags |= EXT4_MF_FS_ABORTED;
1541 		return 1;
1542 	case Opt_i_version:
1543 		sb->s_flags |= MS_I_VERSION;
1544 		return 1;
1545 	case Opt_journal_dev:
1546 		if (is_remount) {
1547 			ext4_msg(sb, KERN_ERR,
1548 				 "Cannot specify journal on remount");
1549 			return -1;
1550 		}
1551 		*journal_devnum = arg;
1552 		return 1;
1553 	case Opt_journal_ioprio:
1554 		if (arg < 0 || arg > 7)
1555 			return -1;
1556 		*journal_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, arg);
1557 		return 1;
1558 	}
1559 
1560 	for (m = ext4_mount_opts; m->token != Opt_err; m++) {
1561 		if (token != m->token)
1562 			continue;
1563 		if (args->from && (m->flags & MOPT_GTE0) && (arg < 0))
1564 			return -1;
1565 		if (m->flags & MOPT_EXPLICIT)
1566 			set_opt2(sb, EXPLICIT_DELALLOC);
1567 		if (m->flags & MOPT_CLEAR_ERR)
1568 			clear_opt(sb, ERRORS_MASK);
1569 		if (token == Opt_noquota && sb_any_quota_loaded(sb)) {
1570 			ext4_msg(sb, KERN_ERR, "Cannot change quota "
1571 				 "options when quota turned on");
1572 			return -1;
1573 		}
1574 
1575 		if (m->flags & MOPT_NOSUPPORT) {
1576 			ext4_msg(sb, KERN_ERR, "%s option not supported", opt);
1577 		} else if (token == Opt_commit) {
1578 			if (arg == 0)
1579 				arg = JBD2_DEFAULT_MAX_COMMIT_AGE;
1580 			sbi->s_commit_interval = HZ * arg;
1581 		} else if (token == Opt_max_batch_time) {
1582 			if (arg == 0)
1583 				arg = EXT4_DEF_MAX_BATCH_TIME;
1584 			sbi->s_max_batch_time = arg;
1585 		} else if (token == Opt_min_batch_time) {
1586 			sbi->s_min_batch_time = arg;
1587 		} else if (token == Opt_inode_readahead_blks) {
1588 			if (arg > (1 << 30))
1589 				return -1;
1590 			if (arg && !is_power_of_2(arg)) {
1591 				ext4_msg(sb, KERN_ERR,
1592 					 "EXT4-fs: inode_readahead_blks"
1593 					 " must be a power of 2");
1594 				return -1;
1595 			}
1596 			sbi->s_inode_readahead_blks = arg;
1597 		} else if (token == Opt_init_itable) {
1598 			set_opt(sb, INIT_INODE_TABLE);
1599 			if (!args->from)
1600 				arg = EXT4_DEF_LI_WAIT_MULT;
1601 			sbi->s_li_wait_mult = arg;
1602 		} else if (token == Opt_stripe) {
1603 			sbi->s_stripe = arg;
1604 		} else if (m->flags & MOPT_DATAJ) {
1605 			if (is_remount) {
1606 				if (!sbi->s_journal)
1607 					ext4_msg(sb, KERN_WARNING, "Remounting file system with no journal so ignoring journalled data option");
1608 				else if (test_opt(sb, DATA_FLAGS) !=
1609 					 m->mount_opt) {
1610 					ext4_msg(sb, KERN_ERR,
1611 					 "Cannot change data mode on remount");
1612 					return -1;
1613 				}
1614 			} else {
1615 				clear_opt(sb, DATA_FLAGS);
1616 				sbi->s_mount_opt |= m->mount_opt;
1617 			}
1618 #ifdef CONFIG_QUOTA
1619 		} else if (m->flags & MOPT_QFMT) {
1620 			if (sb_any_quota_loaded(sb) &&
1621 			    sbi->s_jquota_fmt != m->mount_opt) {
1622 				ext4_msg(sb, KERN_ERR, "Cannot "
1623 					 "change journaled quota options "
1624 					 "when quota turned on");
1625 				return -1;
1626 			}
1627 			sbi->s_jquota_fmt = m->mount_opt;
1628 #endif
1629 		} else {
1630 			if (!args->from)
1631 				arg = 1;
1632 			if (m->flags & MOPT_CLEAR)
1633 				arg = !arg;
1634 			else if (unlikely(!(m->flags & MOPT_SET))) {
1635 				ext4_msg(sb, KERN_WARNING,
1636 					 "buggy handling of option %s", opt);
1637 				WARN_ON(1);
1638 				return -1;
1639 			}
1640 			if (arg != 0)
1641 				sbi->s_mount_opt |= m->mount_opt;
1642 			else
1643 				sbi->s_mount_opt &= ~m->mount_opt;
1644 		}
1645 		return 1;
1646 	}
1647 	ext4_msg(sb, KERN_ERR, "Unrecognized mount option \"%s\" "
1648 		 "or missing value", opt);
1649 	return -1;
1650 }
1651 
1652 static int parse_options(char *options, struct super_block *sb,
1653 			 unsigned long *journal_devnum,
1654 			 unsigned int *journal_ioprio,
1655 			 int is_remount)
1656 {
1657 #ifdef CONFIG_QUOTA
1658 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1659 #endif
1660 	char *p;
1661 	substring_t args[MAX_OPT_ARGS];
1662 	int token;
1663 
1664 	if (!options)
1665 		return 1;
1666 
1667 	while ((p = strsep(&options, ",")) != NULL) {
1668 		if (!*p)
1669 			continue;
1670 		/*
1671 		 * Initialize args struct so we know whether arg was
1672 		 * found; some options take optional arguments.
1673 		 */
1674 		args[0].to = args[0].from = 0;
1675 		token = match_token(p, tokens, args);
1676 		if (handle_mount_opt(sb, p, token, args, journal_devnum,
1677 				     journal_ioprio, is_remount) < 0)
1678 			return 0;
1679 	}
1680 #ifdef CONFIG_QUOTA
1681 	if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
1682 		if (test_opt(sb, USRQUOTA) && sbi->s_qf_names[USRQUOTA])
1683 			clear_opt(sb, USRQUOTA);
1684 
1685 		if (test_opt(sb, GRPQUOTA) && sbi->s_qf_names[GRPQUOTA])
1686 			clear_opt(sb, GRPQUOTA);
1687 
1688 		if (test_opt(sb, GRPQUOTA) || test_opt(sb, USRQUOTA)) {
1689 			ext4_msg(sb, KERN_ERR, "old and new quota "
1690 					"format mixing");
1691 			return 0;
1692 		}
1693 
1694 		if (!sbi->s_jquota_fmt) {
1695 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1696 					"not specified");
1697 			return 0;
1698 		}
1699 	} else {
1700 		if (sbi->s_jquota_fmt) {
1701 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1702 					"specified with no journaling "
1703 					"enabled");
1704 			return 0;
1705 		}
1706 	}
1707 #endif
1708 	return 1;
1709 }
1710 
1711 static inline void ext4_show_quota_options(struct seq_file *seq,
1712 					   struct super_block *sb)
1713 {
1714 #if defined(CONFIG_QUOTA)
1715 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1716 
1717 	if (sbi->s_jquota_fmt) {
1718 		char *fmtname = "";
1719 
1720 		switch (sbi->s_jquota_fmt) {
1721 		case QFMT_VFS_OLD:
1722 			fmtname = "vfsold";
1723 			break;
1724 		case QFMT_VFS_V0:
1725 			fmtname = "vfsv0";
1726 			break;
1727 		case QFMT_VFS_V1:
1728 			fmtname = "vfsv1";
1729 			break;
1730 		}
1731 		seq_printf(seq, ",jqfmt=%s", fmtname);
1732 	}
1733 
1734 	if (sbi->s_qf_names[USRQUOTA])
1735 		seq_printf(seq, ",usrjquota=%s", sbi->s_qf_names[USRQUOTA]);
1736 
1737 	if (sbi->s_qf_names[GRPQUOTA])
1738 		seq_printf(seq, ",grpjquota=%s", sbi->s_qf_names[GRPQUOTA]);
1739 
1740 	if (test_opt(sb, USRQUOTA))
1741 		seq_puts(seq, ",usrquota");
1742 
1743 	if (test_opt(sb, GRPQUOTA))
1744 		seq_puts(seq, ",grpquota");
1745 #endif
1746 }
1747 
1748 static const char *token2str(int token)
1749 {
1750 	static const struct match_token *t;
1751 
1752 	for (t = tokens; t->token != Opt_err; t++)
1753 		if (t->token == token && !strchr(t->pattern, '='))
1754 			break;
1755 	return t->pattern;
1756 }
1757 
1758 /*
1759  * Show an option if
1760  *  - it's set to a non-default value OR
1761  *  - if the per-sb default is different from the global default
1762  */
1763 static int _ext4_show_options(struct seq_file *seq, struct super_block *sb,
1764 			      int nodefs)
1765 {
1766 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1767 	struct ext4_super_block *es = sbi->s_es;
1768 	int def_errors, def_mount_opt = nodefs ? 0 : sbi->s_def_mount_opt;
1769 	const struct mount_opts *m;
1770 	char sep = nodefs ? '\n' : ',';
1771 
1772 #define SEQ_OPTS_PUTS(str) seq_printf(seq, "%c" str, sep)
1773 #define SEQ_OPTS_PRINT(str, arg) seq_printf(seq, "%c" str, sep, arg)
1774 
1775 	if (sbi->s_sb_block != 1)
1776 		SEQ_OPTS_PRINT("sb=%llu", sbi->s_sb_block);
1777 
1778 	for (m = ext4_mount_opts; m->token != Opt_err; m++) {
1779 		int want_set = m->flags & MOPT_SET;
1780 		if (((m->flags & (MOPT_SET|MOPT_CLEAR)) == 0) ||
1781 		    (m->flags & MOPT_CLEAR_ERR))
1782 			continue;
1783 		if (!(m->mount_opt & (sbi->s_mount_opt ^ def_mount_opt)))
1784 			continue; /* skip if same as the default */
1785 		if ((want_set &&
1786 		     (sbi->s_mount_opt & m->mount_opt) != m->mount_opt) ||
1787 		    (!want_set && (sbi->s_mount_opt & m->mount_opt)))
1788 			continue; /* select Opt_noFoo vs Opt_Foo */
1789 		SEQ_OPTS_PRINT("%s", token2str(m->token));
1790 	}
1791 
1792 	if (nodefs || !uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT4_DEF_RESUID)) ||
1793 	    le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID)
1794 		SEQ_OPTS_PRINT("resuid=%u",
1795 				from_kuid_munged(&init_user_ns, sbi->s_resuid));
1796 	if (nodefs || !gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT4_DEF_RESGID)) ||
1797 	    le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID)
1798 		SEQ_OPTS_PRINT("resgid=%u",
1799 				from_kgid_munged(&init_user_ns, sbi->s_resgid));
1800 	def_errors = nodefs ? -1 : le16_to_cpu(es->s_errors);
1801 	if (test_opt(sb, ERRORS_RO) && def_errors != EXT4_ERRORS_RO)
1802 		SEQ_OPTS_PUTS("errors=remount-ro");
1803 	if (test_opt(sb, ERRORS_CONT) && def_errors != EXT4_ERRORS_CONTINUE)
1804 		SEQ_OPTS_PUTS("errors=continue");
1805 	if (test_opt(sb, ERRORS_PANIC) && def_errors != EXT4_ERRORS_PANIC)
1806 		SEQ_OPTS_PUTS("errors=panic");
1807 	if (nodefs || sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ)
1808 		SEQ_OPTS_PRINT("commit=%lu", sbi->s_commit_interval / HZ);
1809 	if (nodefs || sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME)
1810 		SEQ_OPTS_PRINT("min_batch_time=%u", sbi->s_min_batch_time);
1811 	if (nodefs || sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME)
1812 		SEQ_OPTS_PRINT("max_batch_time=%u", sbi->s_max_batch_time);
1813 	if (sb->s_flags & MS_I_VERSION)
1814 		SEQ_OPTS_PUTS("i_version");
1815 	if (nodefs || sbi->s_stripe)
1816 		SEQ_OPTS_PRINT("stripe=%lu", sbi->s_stripe);
1817 	if (EXT4_MOUNT_DATA_FLAGS & (sbi->s_mount_opt ^ def_mount_opt)) {
1818 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
1819 			SEQ_OPTS_PUTS("data=journal");
1820 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
1821 			SEQ_OPTS_PUTS("data=ordered");
1822 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
1823 			SEQ_OPTS_PUTS("data=writeback");
1824 	}
1825 	if (nodefs ||
1826 	    sbi->s_inode_readahead_blks != EXT4_DEF_INODE_READAHEAD_BLKS)
1827 		SEQ_OPTS_PRINT("inode_readahead_blks=%u",
1828 			       sbi->s_inode_readahead_blks);
1829 
1830 	if (nodefs || (test_opt(sb, INIT_INODE_TABLE) &&
1831 		       (sbi->s_li_wait_mult != EXT4_DEF_LI_WAIT_MULT)))
1832 		SEQ_OPTS_PRINT("init_itable=%u", sbi->s_li_wait_mult);
1833 
1834 	ext4_show_quota_options(seq, sb);
1835 	return 0;
1836 }
1837 
1838 static int ext4_show_options(struct seq_file *seq, struct dentry *root)
1839 {
1840 	return _ext4_show_options(seq, root->d_sb, 0);
1841 }
1842 
1843 static int options_seq_show(struct seq_file *seq, void *offset)
1844 {
1845 	struct super_block *sb = seq->private;
1846 	int rc;
1847 
1848 	seq_puts(seq, (sb->s_flags & MS_RDONLY) ? "ro" : "rw");
1849 	rc = _ext4_show_options(seq, sb, 1);
1850 	seq_puts(seq, "\n");
1851 	return rc;
1852 }
1853 
1854 static int options_open_fs(struct inode *inode, struct file *file)
1855 {
1856 	return single_open(file, options_seq_show, PDE(inode)->data);
1857 }
1858 
1859 static const struct file_operations ext4_seq_options_fops = {
1860 	.owner = THIS_MODULE,
1861 	.open = options_open_fs,
1862 	.read = seq_read,
1863 	.llseek = seq_lseek,
1864 	.release = single_release,
1865 };
1866 
1867 static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
1868 			    int read_only)
1869 {
1870 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1871 	int res = 0;
1872 
1873 	if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
1874 		ext4_msg(sb, KERN_ERR, "revision level too high, "
1875 			 "forcing read-only mode");
1876 		res = MS_RDONLY;
1877 	}
1878 	if (read_only)
1879 		goto done;
1880 	if (!(sbi->s_mount_state & EXT4_VALID_FS))
1881 		ext4_msg(sb, KERN_WARNING, "warning: mounting unchecked fs, "
1882 			 "running e2fsck is recommended");
1883 	else if ((sbi->s_mount_state & EXT4_ERROR_FS))
1884 		ext4_msg(sb, KERN_WARNING,
1885 			 "warning: mounting fs with errors, "
1886 			 "running e2fsck is recommended");
1887 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) > 0 &&
1888 		 le16_to_cpu(es->s_mnt_count) >=
1889 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
1890 		ext4_msg(sb, KERN_WARNING,
1891 			 "warning: maximal mount count reached, "
1892 			 "running e2fsck is recommended");
1893 	else if (le32_to_cpu(es->s_checkinterval) &&
1894 		(le32_to_cpu(es->s_lastcheck) +
1895 			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
1896 		ext4_msg(sb, KERN_WARNING,
1897 			 "warning: checktime reached, "
1898 			 "running e2fsck is recommended");
1899 	if (!sbi->s_journal)
1900 		es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1901 	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
1902 		es->s_max_mnt_count = cpu_to_le16(EXT4_DFL_MAX_MNT_COUNT);
1903 	le16_add_cpu(&es->s_mnt_count, 1);
1904 	es->s_mtime = cpu_to_le32(get_seconds());
1905 	ext4_update_dynamic_rev(sb);
1906 	if (sbi->s_journal)
1907 		EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
1908 
1909 	ext4_commit_super(sb, 1);
1910 done:
1911 	if (test_opt(sb, DEBUG))
1912 		printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, "
1913 				"bpg=%lu, ipg=%lu, mo=%04x, mo2=%04x]\n",
1914 			sb->s_blocksize,
1915 			sbi->s_groups_count,
1916 			EXT4_BLOCKS_PER_GROUP(sb),
1917 			EXT4_INODES_PER_GROUP(sb),
1918 			sbi->s_mount_opt, sbi->s_mount_opt2);
1919 
1920 	cleancache_init_fs(sb);
1921 	return res;
1922 }
1923 
1924 static int ext4_fill_flex_info(struct super_block *sb)
1925 {
1926 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1927 	struct ext4_group_desc *gdp = NULL;
1928 	ext4_group_t flex_group_count;
1929 	ext4_group_t flex_group;
1930 	unsigned int groups_per_flex = 0;
1931 	size_t size;
1932 	int i;
1933 
1934 	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
1935 	if (sbi->s_log_groups_per_flex < 1 || sbi->s_log_groups_per_flex > 31) {
1936 		sbi->s_log_groups_per_flex = 0;
1937 		return 1;
1938 	}
1939 	groups_per_flex = 1 << sbi->s_log_groups_per_flex;
1940 
1941 	/* We allocate both existing and potentially added groups */
1942 	flex_group_count = ((sbi->s_groups_count + groups_per_flex - 1) +
1943 			((le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) + 1) <<
1944 			      EXT4_DESC_PER_BLOCK_BITS(sb))) / groups_per_flex;
1945 	size = flex_group_count * sizeof(struct flex_groups);
1946 	sbi->s_flex_groups = ext4_kvzalloc(size, GFP_KERNEL);
1947 	if (sbi->s_flex_groups == NULL) {
1948 		ext4_msg(sb, KERN_ERR, "not enough memory for %u flex groups",
1949 			 flex_group_count);
1950 		goto failed;
1951 	}
1952 
1953 	for (i = 0; i < sbi->s_groups_count; i++) {
1954 		gdp = ext4_get_group_desc(sb, i, NULL);
1955 
1956 		flex_group = ext4_flex_group(sbi, i);
1957 		atomic_add(ext4_free_inodes_count(sb, gdp),
1958 			   &sbi->s_flex_groups[flex_group].free_inodes);
1959 		atomic_add(ext4_free_group_clusters(sb, gdp),
1960 			   &sbi->s_flex_groups[flex_group].free_clusters);
1961 		atomic_add(ext4_used_dirs_count(sb, gdp),
1962 			   &sbi->s_flex_groups[flex_group].used_dirs);
1963 	}
1964 
1965 	return 1;
1966 failed:
1967 	return 0;
1968 }
1969 
1970 static __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
1971 				   struct ext4_group_desc *gdp)
1972 {
1973 	int offset;
1974 	__u16 crc = 0;
1975 	__le32 le_group = cpu_to_le32(block_group);
1976 
1977 	if ((sbi->s_es->s_feature_ro_compat &
1978 	     cpu_to_le32(EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))) {
1979 		/* Use new metadata_csum algorithm */
1980 		__u16 old_csum;
1981 		__u32 csum32;
1982 
1983 		old_csum = gdp->bg_checksum;
1984 		gdp->bg_checksum = 0;
1985 		csum32 = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&le_group,
1986 				     sizeof(le_group));
1987 		csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp,
1988 				     sbi->s_desc_size);
1989 		gdp->bg_checksum = old_csum;
1990 
1991 		crc = csum32 & 0xFFFF;
1992 		goto out;
1993 	}
1994 
1995 	/* old crc16 code */
1996 	offset = offsetof(struct ext4_group_desc, bg_checksum);
1997 
1998 	crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
1999 	crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
2000 	crc = crc16(crc, (__u8 *)gdp, offset);
2001 	offset += sizeof(gdp->bg_checksum); /* skip checksum */
2002 	/* for checksum of struct ext4_group_desc do the rest...*/
2003 	if ((sbi->s_es->s_feature_incompat &
2004 	     cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) &&
2005 	    offset < le16_to_cpu(sbi->s_es->s_desc_size))
2006 		crc = crc16(crc, (__u8 *)gdp + offset,
2007 			    le16_to_cpu(sbi->s_es->s_desc_size) -
2008 				offset);
2009 
2010 out:
2011 	return cpu_to_le16(crc);
2012 }
2013 
2014 int ext4_group_desc_csum_verify(struct super_block *sb, __u32 block_group,
2015 				struct ext4_group_desc *gdp)
2016 {
2017 	if (ext4_has_group_desc_csum(sb) &&
2018 	    (gdp->bg_checksum != ext4_group_desc_csum(EXT4_SB(sb),
2019 						      block_group, gdp)))
2020 		return 0;
2021 
2022 	return 1;
2023 }
2024 
2025 void ext4_group_desc_csum_set(struct super_block *sb, __u32 block_group,
2026 			      struct ext4_group_desc *gdp)
2027 {
2028 	if (!ext4_has_group_desc_csum(sb))
2029 		return;
2030 	gdp->bg_checksum = ext4_group_desc_csum(EXT4_SB(sb), block_group, gdp);
2031 }
2032 
2033 /* Called at mount-time, super-block is locked */
2034 static int ext4_check_descriptors(struct super_block *sb,
2035 				  ext4_group_t *first_not_zeroed)
2036 {
2037 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2038 	ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
2039 	ext4_fsblk_t last_block;
2040 	ext4_fsblk_t block_bitmap;
2041 	ext4_fsblk_t inode_bitmap;
2042 	ext4_fsblk_t inode_table;
2043 	int flexbg_flag = 0;
2044 	ext4_group_t i, grp = sbi->s_groups_count;
2045 
2046 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
2047 		flexbg_flag = 1;
2048 
2049 	ext4_debug("Checking group descriptors");
2050 
2051 	for (i = 0; i < sbi->s_groups_count; i++) {
2052 		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
2053 
2054 		if (i == sbi->s_groups_count - 1 || flexbg_flag)
2055 			last_block = ext4_blocks_count(sbi->s_es) - 1;
2056 		else
2057 			last_block = first_block +
2058 				(EXT4_BLOCKS_PER_GROUP(sb) - 1);
2059 
2060 		if ((grp == sbi->s_groups_count) &&
2061 		   !(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2062 			grp = i;
2063 
2064 		block_bitmap = ext4_block_bitmap(sb, gdp);
2065 		if (block_bitmap < first_block || block_bitmap > last_block) {
2066 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2067 			       "Block bitmap for group %u not in group "
2068 			       "(block %llu)!", i, block_bitmap);
2069 			return 0;
2070 		}
2071 		inode_bitmap = ext4_inode_bitmap(sb, gdp);
2072 		if (inode_bitmap < first_block || inode_bitmap > last_block) {
2073 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2074 			       "Inode bitmap for group %u not in group "
2075 			       "(block %llu)!", i, inode_bitmap);
2076 			return 0;
2077 		}
2078 		inode_table = ext4_inode_table(sb, gdp);
2079 		if (inode_table < first_block ||
2080 		    inode_table + sbi->s_itb_per_group - 1 > last_block) {
2081 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2082 			       "Inode table for group %u not in group "
2083 			       "(block %llu)!", i, inode_table);
2084 			return 0;
2085 		}
2086 		ext4_lock_group(sb, i);
2087 		if (!ext4_group_desc_csum_verify(sb, i, gdp)) {
2088 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2089 				 "Checksum for group %u failed (%u!=%u)",
2090 				 i, le16_to_cpu(ext4_group_desc_csum(sbi, i,
2091 				     gdp)), le16_to_cpu(gdp->bg_checksum));
2092 			if (!(sb->s_flags & MS_RDONLY)) {
2093 				ext4_unlock_group(sb, i);
2094 				return 0;
2095 			}
2096 		}
2097 		ext4_unlock_group(sb, i);
2098 		if (!flexbg_flag)
2099 			first_block += EXT4_BLOCKS_PER_GROUP(sb);
2100 	}
2101 	if (NULL != first_not_zeroed)
2102 		*first_not_zeroed = grp;
2103 
2104 	ext4_free_blocks_count_set(sbi->s_es,
2105 				   EXT4_C2B(sbi, ext4_count_free_clusters(sb)));
2106 	sbi->s_es->s_free_inodes_count =cpu_to_le32(ext4_count_free_inodes(sb));
2107 	return 1;
2108 }
2109 
2110 /* ext4_orphan_cleanup() walks a singly-linked list of inodes (starting at
2111  * the superblock) which were deleted from all directories, but held open by
2112  * a process at the time of a crash.  We walk the list and try to delete these
2113  * inodes at recovery time (only with a read-write filesystem).
2114  *
2115  * In order to keep the orphan inode chain consistent during traversal (in
2116  * case of crash during recovery), we link each inode into the superblock
2117  * orphan list_head and handle it the same way as an inode deletion during
2118  * normal operation (which journals the operations for us).
2119  *
2120  * We only do an iget() and an iput() on each inode, which is very safe if we
2121  * accidentally point at an in-use or already deleted inode.  The worst that
2122  * can happen in this case is that we get a "bit already cleared" message from
2123  * ext4_free_inode().  The only reason we would point at a wrong inode is if
2124  * e2fsck was run on this filesystem, and it must have already done the orphan
2125  * inode cleanup for us, so we can safely abort without any further action.
2126  */
2127 static void ext4_orphan_cleanup(struct super_block *sb,
2128 				struct ext4_super_block *es)
2129 {
2130 	unsigned int s_flags = sb->s_flags;
2131 	int nr_orphans = 0, nr_truncates = 0;
2132 #ifdef CONFIG_QUOTA
2133 	int i;
2134 #endif
2135 	if (!es->s_last_orphan) {
2136 		jbd_debug(4, "no orphan inodes to clean up\n");
2137 		return;
2138 	}
2139 
2140 	if (bdev_read_only(sb->s_bdev)) {
2141 		ext4_msg(sb, KERN_ERR, "write access "
2142 			"unavailable, skipping orphan cleanup");
2143 		return;
2144 	}
2145 
2146 	/* Check if feature set would not allow a r/w mount */
2147 	if (!ext4_feature_set_ok(sb, 0)) {
2148 		ext4_msg(sb, KERN_INFO, "Skipping orphan cleanup due to "
2149 			 "unknown ROCOMPAT features");
2150 		return;
2151 	}
2152 
2153 	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
2154 		if (es->s_last_orphan)
2155 			jbd_debug(1, "Errors on filesystem, "
2156 				  "clearing orphan list.\n");
2157 		es->s_last_orphan = 0;
2158 		jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
2159 		return;
2160 	}
2161 
2162 	if (s_flags & MS_RDONLY) {
2163 		ext4_msg(sb, KERN_INFO, "orphan cleanup on readonly fs");
2164 		sb->s_flags &= ~MS_RDONLY;
2165 	}
2166 #ifdef CONFIG_QUOTA
2167 	/* Needed for iput() to work correctly and not trash data */
2168 	sb->s_flags |= MS_ACTIVE;
2169 	/* Turn on quotas so that they are updated correctly */
2170 	for (i = 0; i < MAXQUOTAS; i++) {
2171 		if (EXT4_SB(sb)->s_qf_names[i]) {
2172 			int ret = ext4_quota_on_mount(sb, i);
2173 			if (ret < 0)
2174 				ext4_msg(sb, KERN_ERR,
2175 					"Cannot turn on journaled "
2176 					"quota: error %d", ret);
2177 		}
2178 	}
2179 #endif
2180 
2181 	while (es->s_last_orphan) {
2182 		struct inode *inode;
2183 
2184 		inode = ext4_orphan_get(sb, le32_to_cpu(es->s_last_orphan));
2185 		if (IS_ERR(inode)) {
2186 			es->s_last_orphan = 0;
2187 			break;
2188 		}
2189 
2190 		list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
2191 		dquot_initialize(inode);
2192 		if (inode->i_nlink) {
2193 			ext4_msg(sb, KERN_DEBUG,
2194 				"%s: truncating inode %lu to %lld bytes",
2195 				__func__, inode->i_ino, inode->i_size);
2196 			jbd_debug(2, "truncating inode %lu to %lld bytes\n",
2197 				  inode->i_ino, inode->i_size);
2198 			ext4_truncate(inode);
2199 			nr_truncates++;
2200 		} else {
2201 			ext4_msg(sb, KERN_DEBUG,
2202 				"%s: deleting unreferenced inode %lu",
2203 				__func__, inode->i_ino);
2204 			jbd_debug(2, "deleting unreferenced inode %lu\n",
2205 				  inode->i_ino);
2206 			nr_orphans++;
2207 		}
2208 		iput(inode);  /* The delete magic happens here! */
2209 	}
2210 
2211 #define PLURAL(x) (x), ((x) == 1) ? "" : "s"
2212 
2213 	if (nr_orphans)
2214 		ext4_msg(sb, KERN_INFO, "%d orphan inode%s deleted",
2215 		       PLURAL(nr_orphans));
2216 	if (nr_truncates)
2217 		ext4_msg(sb, KERN_INFO, "%d truncate%s cleaned up",
2218 		       PLURAL(nr_truncates));
2219 #ifdef CONFIG_QUOTA
2220 	/* Turn quotas off */
2221 	for (i = 0; i < MAXQUOTAS; i++) {
2222 		if (sb_dqopt(sb)->files[i])
2223 			dquot_quota_off(sb, i);
2224 	}
2225 #endif
2226 	sb->s_flags = s_flags; /* Restore MS_RDONLY status */
2227 }
2228 
2229 /*
2230  * Maximal extent format file size.
2231  * Resulting logical blkno at s_maxbytes must fit in our on-disk
2232  * extent format containers, within a sector_t, and within i_blocks
2233  * in the vfs.  ext4 inode has 48 bits of i_block in fsblock units,
2234  * so that won't be a limiting factor.
2235  *
2236  * However there is other limiting factor. We do store extents in the form
2237  * of starting block and length, hence the resulting length of the extent
2238  * covering maximum file size must fit into on-disk format containers as
2239  * well. Given that length is always by 1 unit bigger than max unit (because
2240  * we count 0 as well) we have to lower the s_maxbytes by one fs block.
2241  *
2242  * Note, this does *not* consider any metadata overhead for vfs i_blocks.
2243  */
2244 static loff_t ext4_max_size(int blkbits, int has_huge_files)
2245 {
2246 	loff_t res;
2247 	loff_t upper_limit = MAX_LFS_FILESIZE;
2248 
2249 	/* small i_blocks in vfs inode? */
2250 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2251 		/*
2252 		 * CONFIG_LBDAF is not enabled implies the inode
2253 		 * i_block represent total blocks in 512 bytes
2254 		 * 32 == size of vfs inode i_blocks * 8
2255 		 */
2256 		upper_limit = (1LL << 32) - 1;
2257 
2258 		/* total blocks in file system block size */
2259 		upper_limit >>= (blkbits - 9);
2260 		upper_limit <<= blkbits;
2261 	}
2262 
2263 	/*
2264 	 * 32-bit extent-start container, ee_block. We lower the maxbytes
2265 	 * by one fs block, so ee_len can cover the extent of maximum file
2266 	 * size
2267 	 */
2268 	res = (1LL << 32) - 1;
2269 	res <<= blkbits;
2270 
2271 	/* Sanity check against vm- & vfs- imposed limits */
2272 	if (res > upper_limit)
2273 		res = upper_limit;
2274 
2275 	return res;
2276 }
2277 
2278 /*
2279  * Maximal bitmap file size.  There is a direct, and {,double-,triple-}indirect
2280  * block limit, and also a limit of (2^48 - 1) 512-byte sectors in i_blocks.
2281  * We need to be 1 filesystem block less than the 2^48 sector limit.
2282  */
2283 static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
2284 {
2285 	loff_t res = EXT4_NDIR_BLOCKS;
2286 	int meta_blocks;
2287 	loff_t upper_limit;
2288 	/* This is calculated to be the largest file size for a dense, block
2289 	 * mapped file such that the file's total number of 512-byte sectors,
2290 	 * including data and all indirect blocks, does not exceed (2^48 - 1).
2291 	 *
2292 	 * __u32 i_blocks_lo and _u16 i_blocks_high represent the total
2293 	 * number of 512-byte sectors of the file.
2294 	 */
2295 
2296 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2297 		/*
2298 		 * !has_huge_files or CONFIG_LBDAF not enabled implies that
2299 		 * the inode i_block field represents total file blocks in
2300 		 * 2^32 512-byte sectors == size of vfs inode i_blocks * 8
2301 		 */
2302 		upper_limit = (1LL << 32) - 1;
2303 
2304 		/* total blocks in file system block size */
2305 		upper_limit >>= (bits - 9);
2306 
2307 	} else {
2308 		/*
2309 		 * We use 48 bit ext4_inode i_blocks
2310 		 * With EXT4_HUGE_FILE_FL set the i_blocks
2311 		 * represent total number of blocks in
2312 		 * file system block size
2313 		 */
2314 		upper_limit = (1LL << 48) - 1;
2315 
2316 	}
2317 
2318 	/* indirect blocks */
2319 	meta_blocks = 1;
2320 	/* double indirect blocks */
2321 	meta_blocks += 1 + (1LL << (bits-2));
2322 	/* tripple indirect blocks */
2323 	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
2324 
2325 	upper_limit -= meta_blocks;
2326 	upper_limit <<= bits;
2327 
2328 	res += 1LL << (bits-2);
2329 	res += 1LL << (2*(bits-2));
2330 	res += 1LL << (3*(bits-2));
2331 	res <<= bits;
2332 	if (res > upper_limit)
2333 		res = upper_limit;
2334 
2335 	if (res > MAX_LFS_FILESIZE)
2336 		res = MAX_LFS_FILESIZE;
2337 
2338 	return res;
2339 }
2340 
2341 static ext4_fsblk_t descriptor_loc(struct super_block *sb,
2342 				   ext4_fsblk_t logical_sb_block, int nr)
2343 {
2344 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2345 	ext4_group_t bg, first_meta_bg;
2346 	int has_super = 0;
2347 
2348 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
2349 
2350 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
2351 	    nr < first_meta_bg)
2352 		return logical_sb_block + nr + 1;
2353 	bg = sbi->s_desc_per_block * nr;
2354 	if (ext4_bg_has_super(sb, bg))
2355 		has_super = 1;
2356 
2357 	return (has_super + ext4_group_first_block_no(sb, bg));
2358 }
2359 
2360 /**
2361  * ext4_get_stripe_size: Get the stripe size.
2362  * @sbi: In memory super block info
2363  *
2364  * If we have specified it via mount option, then
2365  * use the mount option value. If the value specified at mount time is
2366  * greater than the blocks per group use the super block value.
2367  * If the super block value is greater than blocks per group return 0.
2368  * Allocator needs it be less than blocks per group.
2369  *
2370  */
2371 static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi)
2372 {
2373 	unsigned long stride = le16_to_cpu(sbi->s_es->s_raid_stride);
2374 	unsigned long stripe_width =
2375 			le32_to_cpu(sbi->s_es->s_raid_stripe_width);
2376 	int ret;
2377 
2378 	if (sbi->s_stripe && sbi->s_stripe <= sbi->s_blocks_per_group)
2379 		ret = sbi->s_stripe;
2380 	else if (stripe_width <= sbi->s_blocks_per_group)
2381 		ret = stripe_width;
2382 	else if (stride <= sbi->s_blocks_per_group)
2383 		ret = stride;
2384 	else
2385 		ret = 0;
2386 
2387 	/*
2388 	 * If the stripe width is 1, this makes no sense and
2389 	 * we set it to 0 to turn off stripe handling code.
2390 	 */
2391 	if (ret <= 1)
2392 		ret = 0;
2393 
2394 	return ret;
2395 }
2396 
2397 /* sysfs supprt */
2398 
2399 struct ext4_attr {
2400 	struct attribute attr;
2401 	ssize_t (*show)(struct ext4_attr *, struct ext4_sb_info *, char *);
2402 	ssize_t (*store)(struct ext4_attr *, struct ext4_sb_info *,
2403 			 const char *, size_t);
2404 	int offset;
2405 };
2406 
2407 static int parse_strtoul(const char *buf,
2408 		unsigned long max, unsigned long *value)
2409 {
2410 	char *endp;
2411 
2412 	*value = simple_strtoul(skip_spaces(buf), &endp, 0);
2413 	endp = skip_spaces(endp);
2414 	if (*endp || *value > max)
2415 		return -EINVAL;
2416 
2417 	return 0;
2418 }
2419 
2420 static ssize_t delayed_allocation_blocks_show(struct ext4_attr *a,
2421 					      struct ext4_sb_info *sbi,
2422 					      char *buf)
2423 {
2424 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2425 		(s64) EXT4_C2B(sbi,
2426 			percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
2427 }
2428 
2429 static ssize_t session_write_kbytes_show(struct ext4_attr *a,
2430 					 struct ext4_sb_info *sbi, char *buf)
2431 {
2432 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
2433 
2434 	if (!sb->s_bdev->bd_part)
2435 		return snprintf(buf, PAGE_SIZE, "0\n");
2436 	return snprintf(buf, PAGE_SIZE, "%lu\n",
2437 			(part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
2438 			 sbi->s_sectors_written_start) >> 1);
2439 }
2440 
2441 static ssize_t lifetime_write_kbytes_show(struct ext4_attr *a,
2442 					  struct ext4_sb_info *sbi, char *buf)
2443 {
2444 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
2445 
2446 	if (!sb->s_bdev->bd_part)
2447 		return snprintf(buf, PAGE_SIZE, "0\n");
2448 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2449 			(unsigned long long)(sbi->s_kbytes_written +
2450 			((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
2451 			  EXT4_SB(sb)->s_sectors_written_start) >> 1)));
2452 }
2453 
2454 static ssize_t inode_readahead_blks_store(struct ext4_attr *a,
2455 					  struct ext4_sb_info *sbi,
2456 					  const char *buf, size_t count)
2457 {
2458 	unsigned long t;
2459 
2460 	if (parse_strtoul(buf, 0x40000000, &t))
2461 		return -EINVAL;
2462 
2463 	if (t && !is_power_of_2(t))
2464 		return -EINVAL;
2465 
2466 	sbi->s_inode_readahead_blks = t;
2467 	return count;
2468 }
2469 
2470 static ssize_t sbi_ui_show(struct ext4_attr *a,
2471 			   struct ext4_sb_info *sbi, char *buf)
2472 {
2473 	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
2474 
2475 	return snprintf(buf, PAGE_SIZE, "%u\n", *ui);
2476 }
2477 
2478 static ssize_t sbi_ui_store(struct ext4_attr *a,
2479 			    struct ext4_sb_info *sbi,
2480 			    const char *buf, size_t count)
2481 {
2482 	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
2483 	unsigned long t;
2484 
2485 	if (parse_strtoul(buf, 0xffffffff, &t))
2486 		return -EINVAL;
2487 	*ui = t;
2488 	return count;
2489 }
2490 
2491 static ssize_t trigger_test_error(struct ext4_attr *a,
2492 				  struct ext4_sb_info *sbi,
2493 				  const char *buf, size_t count)
2494 {
2495 	int len = count;
2496 
2497 	if (!capable(CAP_SYS_ADMIN))
2498 		return -EPERM;
2499 
2500 	if (len && buf[len-1] == '\n')
2501 		len--;
2502 
2503 	if (len)
2504 		ext4_error(sbi->s_sb, "%.*s", len, buf);
2505 	return count;
2506 }
2507 
2508 #define EXT4_ATTR_OFFSET(_name,_mode,_show,_store,_elname) \
2509 static struct ext4_attr ext4_attr_##_name = {			\
2510 	.attr = {.name = __stringify(_name), .mode = _mode },	\
2511 	.show	= _show,					\
2512 	.store	= _store,					\
2513 	.offset = offsetof(struct ext4_sb_info, _elname),	\
2514 }
2515 #define EXT4_ATTR(name, mode, show, store) \
2516 static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store)
2517 
2518 #define EXT4_INFO_ATTR(name) EXT4_ATTR(name, 0444, NULL, NULL)
2519 #define EXT4_RO_ATTR(name) EXT4_ATTR(name, 0444, name##_show, NULL)
2520 #define EXT4_RW_ATTR(name) EXT4_ATTR(name, 0644, name##_show, name##_store)
2521 #define EXT4_RW_ATTR_SBI_UI(name, elname)	\
2522 	EXT4_ATTR_OFFSET(name, 0644, sbi_ui_show, sbi_ui_store, elname)
2523 #define ATTR_LIST(name) &ext4_attr_##name.attr
2524 
2525 EXT4_RO_ATTR(delayed_allocation_blocks);
2526 EXT4_RO_ATTR(session_write_kbytes);
2527 EXT4_RO_ATTR(lifetime_write_kbytes);
2528 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, sbi_ui_show,
2529 		 inode_readahead_blks_store, s_inode_readahead_blks);
2530 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
2531 EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
2532 EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
2533 EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
2534 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
2535 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
2536 EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
2537 EXT4_RW_ATTR_SBI_UI(max_writeback_mb_bump, s_max_writeback_mb_bump);
2538 EXT4_ATTR(trigger_fs_error, 0200, NULL, trigger_test_error);
2539 
2540 static struct attribute *ext4_attrs[] = {
2541 	ATTR_LIST(delayed_allocation_blocks),
2542 	ATTR_LIST(session_write_kbytes),
2543 	ATTR_LIST(lifetime_write_kbytes),
2544 	ATTR_LIST(inode_readahead_blks),
2545 	ATTR_LIST(inode_goal),
2546 	ATTR_LIST(mb_stats),
2547 	ATTR_LIST(mb_max_to_scan),
2548 	ATTR_LIST(mb_min_to_scan),
2549 	ATTR_LIST(mb_order2_req),
2550 	ATTR_LIST(mb_stream_req),
2551 	ATTR_LIST(mb_group_prealloc),
2552 	ATTR_LIST(max_writeback_mb_bump),
2553 	ATTR_LIST(trigger_fs_error),
2554 	NULL,
2555 };
2556 
2557 /* Features this copy of ext4 supports */
2558 EXT4_INFO_ATTR(lazy_itable_init);
2559 EXT4_INFO_ATTR(batched_discard);
2560 
2561 static struct attribute *ext4_feat_attrs[] = {
2562 	ATTR_LIST(lazy_itable_init),
2563 	ATTR_LIST(batched_discard),
2564 	NULL,
2565 };
2566 
2567 static ssize_t ext4_attr_show(struct kobject *kobj,
2568 			      struct attribute *attr, char *buf)
2569 {
2570 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2571 						s_kobj);
2572 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
2573 
2574 	return a->show ? a->show(a, sbi, buf) : 0;
2575 }
2576 
2577 static ssize_t ext4_attr_store(struct kobject *kobj,
2578 			       struct attribute *attr,
2579 			       const char *buf, size_t len)
2580 {
2581 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2582 						s_kobj);
2583 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
2584 
2585 	return a->store ? a->store(a, sbi, buf, len) : 0;
2586 }
2587 
2588 static void ext4_sb_release(struct kobject *kobj)
2589 {
2590 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2591 						s_kobj);
2592 	complete(&sbi->s_kobj_unregister);
2593 }
2594 
2595 static const struct sysfs_ops ext4_attr_ops = {
2596 	.show	= ext4_attr_show,
2597 	.store	= ext4_attr_store,
2598 };
2599 
2600 static struct kobj_type ext4_ktype = {
2601 	.default_attrs	= ext4_attrs,
2602 	.sysfs_ops	= &ext4_attr_ops,
2603 	.release	= ext4_sb_release,
2604 };
2605 
2606 static void ext4_feat_release(struct kobject *kobj)
2607 {
2608 	complete(&ext4_feat->f_kobj_unregister);
2609 }
2610 
2611 static struct kobj_type ext4_feat_ktype = {
2612 	.default_attrs	= ext4_feat_attrs,
2613 	.sysfs_ops	= &ext4_attr_ops,
2614 	.release	= ext4_feat_release,
2615 };
2616 
2617 /*
2618  * Check whether this filesystem can be mounted based on
2619  * the features present and the RDONLY/RDWR mount requested.
2620  * Returns 1 if this filesystem can be mounted as requested,
2621  * 0 if it cannot be.
2622  */
2623 static int ext4_feature_set_ok(struct super_block *sb, int readonly)
2624 {
2625 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT4_FEATURE_INCOMPAT_SUPP)) {
2626 		ext4_msg(sb, KERN_ERR,
2627 			"Couldn't mount because of "
2628 			"unsupported optional features (%x)",
2629 			(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_incompat) &
2630 			~EXT4_FEATURE_INCOMPAT_SUPP));
2631 		return 0;
2632 	}
2633 
2634 	if (readonly)
2635 		return 1;
2636 
2637 	/* Check that feature set is OK for a read-write mount */
2638 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT4_FEATURE_RO_COMPAT_SUPP)) {
2639 		ext4_msg(sb, KERN_ERR, "couldn't mount RDWR because of "
2640 			 "unsupported optional features (%x)",
2641 			 (le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_ro_compat) &
2642 				~EXT4_FEATURE_RO_COMPAT_SUPP));
2643 		return 0;
2644 	}
2645 	/*
2646 	 * Large file size enabled file system can only be mounted
2647 	 * read-write on 32-bit systems if kernel is built with CONFIG_LBDAF
2648 	 */
2649 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
2650 		if (sizeof(blkcnt_t) < sizeof(u64)) {
2651 			ext4_msg(sb, KERN_ERR, "Filesystem with huge files "
2652 				 "cannot be mounted RDWR without "
2653 				 "CONFIG_LBDAF");
2654 			return 0;
2655 		}
2656 	}
2657 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_BIGALLOC) &&
2658 	    !EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
2659 		ext4_msg(sb, KERN_ERR,
2660 			 "Can't support bigalloc feature without "
2661 			 "extents feature\n");
2662 		return 0;
2663 	}
2664 	return 1;
2665 }
2666 
2667 /*
2668  * This function is called once a day if we have errors logged
2669  * on the file system
2670  */
2671 static void print_daily_error_info(unsigned long arg)
2672 {
2673 	struct super_block *sb = (struct super_block *) arg;
2674 	struct ext4_sb_info *sbi;
2675 	struct ext4_super_block *es;
2676 
2677 	sbi = EXT4_SB(sb);
2678 	es = sbi->s_es;
2679 
2680 	if (es->s_error_count)
2681 		ext4_msg(sb, KERN_NOTICE, "error count: %u",
2682 			 le32_to_cpu(es->s_error_count));
2683 	if (es->s_first_error_time) {
2684 		printk(KERN_NOTICE "EXT4-fs (%s): initial error at %u: %.*s:%d",
2685 		       sb->s_id, le32_to_cpu(es->s_first_error_time),
2686 		       (int) sizeof(es->s_first_error_func),
2687 		       es->s_first_error_func,
2688 		       le32_to_cpu(es->s_first_error_line));
2689 		if (es->s_first_error_ino)
2690 			printk(": inode %u",
2691 			       le32_to_cpu(es->s_first_error_ino));
2692 		if (es->s_first_error_block)
2693 			printk(": block %llu", (unsigned long long)
2694 			       le64_to_cpu(es->s_first_error_block));
2695 		printk("\n");
2696 	}
2697 	if (es->s_last_error_time) {
2698 		printk(KERN_NOTICE "EXT4-fs (%s): last error at %u: %.*s:%d",
2699 		       sb->s_id, le32_to_cpu(es->s_last_error_time),
2700 		       (int) sizeof(es->s_last_error_func),
2701 		       es->s_last_error_func,
2702 		       le32_to_cpu(es->s_last_error_line));
2703 		if (es->s_last_error_ino)
2704 			printk(": inode %u",
2705 			       le32_to_cpu(es->s_last_error_ino));
2706 		if (es->s_last_error_block)
2707 			printk(": block %llu", (unsigned long long)
2708 			       le64_to_cpu(es->s_last_error_block));
2709 		printk("\n");
2710 	}
2711 	mod_timer(&sbi->s_err_report, jiffies + 24*60*60*HZ);  /* Once a day */
2712 }
2713 
2714 /* Find next suitable group and run ext4_init_inode_table */
2715 static int ext4_run_li_request(struct ext4_li_request *elr)
2716 {
2717 	struct ext4_group_desc *gdp = NULL;
2718 	ext4_group_t group, ngroups;
2719 	struct super_block *sb;
2720 	unsigned long timeout = 0;
2721 	int ret = 0;
2722 
2723 	sb = elr->lr_super;
2724 	ngroups = EXT4_SB(sb)->s_groups_count;
2725 
2726 	for (group = elr->lr_next_group; group < ngroups; group++) {
2727 		gdp = ext4_get_group_desc(sb, group, NULL);
2728 		if (!gdp) {
2729 			ret = 1;
2730 			break;
2731 		}
2732 
2733 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2734 			break;
2735 	}
2736 
2737 	if (group == ngroups)
2738 		ret = 1;
2739 
2740 	if (!ret) {
2741 		timeout = jiffies;
2742 		ret = ext4_init_inode_table(sb, group,
2743 					    elr->lr_timeout ? 0 : 1);
2744 		if (elr->lr_timeout == 0) {
2745 			timeout = (jiffies - timeout) *
2746 				  elr->lr_sbi->s_li_wait_mult;
2747 			elr->lr_timeout = timeout;
2748 		}
2749 		elr->lr_next_sched = jiffies + elr->lr_timeout;
2750 		elr->lr_next_group = group + 1;
2751 	}
2752 
2753 	return ret;
2754 }
2755 
2756 /*
2757  * Remove lr_request from the list_request and free the
2758  * request structure. Should be called with li_list_mtx held
2759  */
2760 static void ext4_remove_li_request(struct ext4_li_request *elr)
2761 {
2762 	struct ext4_sb_info *sbi;
2763 
2764 	if (!elr)
2765 		return;
2766 
2767 	sbi = elr->lr_sbi;
2768 
2769 	list_del(&elr->lr_request);
2770 	sbi->s_li_request = NULL;
2771 	kfree(elr);
2772 }
2773 
2774 static void ext4_unregister_li_request(struct super_block *sb)
2775 {
2776 	mutex_lock(&ext4_li_mtx);
2777 	if (!ext4_li_info) {
2778 		mutex_unlock(&ext4_li_mtx);
2779 		return;
2780 	}
2781 
2782 	mutex_lock(&ext4_li_info->li_list_mtx);
2783 	ext4_remove_li_request(EXT4_SB(sb)->s_li_request);
2784 	mutex_unlock(&ext4_li_info->li_list_mtx);
2785 	mutex_unlock(&ext4_li_mtx);
2786 }
2787 
2788 static struct task_struct *ext4_lazyinit_task;
2789 
2790 /*
2791  * This is the function where ext4lazyinit thread lives. It walks
2792  * through the request list searching for next scheduled filesystem.
2793  * When such a fs is found, run the lazy initialization request
2794  * (ext4_rn_li_request) and keep track of the time spend in this
2795  * function. Based on that time we compute next schedule time of
2796  * the request. When walking through the list is complete, compute
2797  * next waking time and put itself into sleep.
2798  */
2799 static int ext4_lazyinit_thread(void *arg)
2800 {
2801 	struct ext4_lazy_init *eli = (struct ext4_lazy_init *)arg;
2802 	struct list_head *pos, *n;
2803 	struct ext4_li_request *elr;
2804 	unsigned long next_wakeup, cur;
2805 
2806 	BUG_ON(NULL == eli);
2807 
2808 cont_thread:
2809 	while (true) {
2810 		next_wakeup = MAX_JIFFY_OFFSET;
2811 
2812 		mutex_lock(&eli->li_list_mtx);
2813 		if (list_empty(&eli->li_request_list)) {
2814 			mutex_unlock(&eli->li_list_mtx);
2815 			goto exit_thread;
2816 		}
2817 
2818 		list_for_each_safe(pos, n, &eli->li_request_list) {
2819 			elr = list_entry(pos, struct ext4_li_request,
2820 					 lr_request);
2821 
2822 			if (time_after_eq(jiffies, elr->lr_next_sched)) {
2823 				if (ext4_run_li_request(elr) != 0) {
2824 					/* error, remove the lazy_init job */
2825 					ext4_remove_li_request(elr);
2826 					continue;
2827 				}
2828 			}
2829 
2830 			if (time_before(elr->lr_next_sched, next_wakeup))
2831 				next_wakeup = elr->lr_next_sched;
2832 		}
2833 		mutex_unlock(&eli->li_list_mtx);
2834 
2835 		try_to_freeze();
2836 
2837 		cur = jiffies;
2838 		if ((time_after_eq(cur, next_wakeup)) ||
2839 		    (MAX_JIFFY_OFFSET == next_wakeup)) {
2840 			cond_resched();
2841 			continue;
2842 		}
2843 
2844 		schedule_timeout_interruptible(next_wakeup - cur);
2845 
2846 		if (kthread_should_stop()) {
2847 			ext4_clear_request_list();
2848 			goto exit_thread;
2849 		}
2850 	}
2851 
2852 exit_thread:
2853 	/*
2854 	 * It looks like the request list is empty, but we need
2855 	 * to check it under the li_list_mtx lock, to prevent any
2856 	 * additions into it, and of course we should lock ext4_li_mtx
2857 	 * to atomically free the list and ext4_li_info, because at
2858 	 * this point another ext4 filesystem could be registering
2859 	 * new one.
2860 	 */
2861 	mutex_lock(&ext4_li_mtx);
2862 	mutex_lock(&eli->li_list_mtx);
2863 	if (!list_empty(&eli->li_request_list)) {
2864 		mutex_unlock(&eli->li_list_mtx);
2865 		mutex_unlock(&ext4_li_mtx);
2866 		goto cont_thread;
2867 	}
2868 	mutex_unlock(&eli->li_list_mtx);
2869 	kfree(ext4_li_info);
2870 	ext4_li_info = NULL;
2871 	mutex_unlock(&ext4_li_mtx);
2872 
2873 	return 0;
2874 }
2875 
2876 static void ext4_clear_request_list(void)
2877 {
2878 	struct list_head *pos, *n;
2879 	struct ext4_li_request *elr;
2880 
2881 	mutex_lock(&ext4_li_info->li_list_mtx);
2882 	list_for_each_safe(pos, n, &ext4_li_info->li_request_list) {
2883 		elr = list_entry(pos, struct ext4_li_request,
2884 				 lr_request);
2885 		ext4_remove_li_request(elr);
2886 	}
2887 	mutex_unlock(&ext4_li_info->li_list_mtx);
2888 }
2889 
2890 static int ext4_run_lazyinit_thread(void)
2891 {
2892 	ext4_lazyinit_task = kthread_run(ext4_lazyinit_thread,
2893 					 ext4_li_info, "ext4lazyinit");
2894 	if (IS_ERR(ext4_lazyinit_task)) {
2895 		int err = PTR_ERR(ext4_lazyinit_task);
2896 		ext4_clear_request_list();
2897 		kfree(ext4_li_info);
2898 		ext4_li_info = NULL;
2899 		printk(KERN_CRIT "EXT4-fs: error %d creating inode table "
2900 				 "initialization thread\n",
2901 				 err);
2902 		return err;
2903 	}
2904 	ext4_li_info->li_state |= EXT4_LAZYINIT_RUNNING;
2905 	return 0;
2906 }
2907 
2908 /*
2909  * Check whether it make sense to run itable init. thread or not.
2910  * If there is at least one uninitialized inode table, return
2911  * corresponding group number, else the loop goes through all
2912  * groups and return total number of groups.
2913  */
2914 static ext4_group_t ext4_has_uninit_itable(struct super_block *sb)
2915 {
2916 	ext4_group_t group, ngroups = EXT4_SB(sb)->s_groups_count;
2917 	struct ext4_group_desc *gdp = NULL;
2918 
2919 	for (group = 0; group < ngroups; group++) {
2920 		gdp = ext4_get_group_desc(sb, group, NULL);
2921 		if (!gdp)
2922 			continue;
2923 
2924 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2925 			break;
2926 	}
2927 
2928 	return group;
2929 }
2930 
2931 static int ext4_li_info_new(void)
2932 {
2933 	struct ext4_lazy_init *eli = NULL;
2934 
2935 	eli = kzalloc(sizeof(*eli), GFP_KERNEL);
2936 	if (!eli)
2937 		return -ENOMEM;
2938 
2939 	INIT_LIST_HEAD(&eli->li_request_list);
2940 	mutex_init(&eli->li_list_mtx);
2941 
2942 	eli->li_state |= EXT4_LAZYINIT_QUIT;
2943 
2944 	ext4_li_info = eli;
2945 
2946 	return 0;
2947 }
2948 
2949 static struct ext4_li_request *ext4_li_request_new(struct super_block *sb,
2950 					    ext4_group_t start)
2951 {
2952 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2953 	struct ext4_li_request *elr;
2954 	unsigned long rnd;
2955 
2956 	elr = kzalloc(sizeof(*elr), GFP_KERNEL);
2957 	if (!elr)
2958 		return NULL;
2959 
2960 	elr->lr_super = sb;
2961 	elr->lr_sbi = sbi;
2962 	elr->lr_next_group = start;
2963 
2964 	/*
2965 	 * Randomize first schedule time of the request to
2966 	 * spread the inode table initialization requests
2967 	 * better.
2968 	 */
2969 	get_random_bytes(&rnd, sizeof(rnd));
2970 	elr->lr_next_sched = jiffies + (unsigned long)rnd %
2971 			     (EXT4_DEF_LI_MAX_START_DELAY * HZ);
2972 
2973 	return elr;
2974 }
2975 
2976 static int ext4_register_li_request(struct super_block *sb,
2977 				    ext4_group_t first_not_zeroed)
2978 {
2979 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2980 	struct ext4_li_request *elr;
2981 	ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
2982 	int ret = 0;
2983 
2984 	if (sbi->s_li_request != NULL) {
2985 		/*
2986 		 * Reset timeout so it can be computed again, because
2987 		 * s_li_wait_mult might have changed.
2988 		 */
2989 		sbi->s_li_request->lr_timeout = 0;
2990 		return 0;
2991 	}
2992 
2993 	if (first_not_zeroed == ngroups ||
2994 	    (sb->s_flags & MS_RDONLY) ||
2995 	    !test_opt(sb, INIT_INODE_TABLE))
2996 		return 0;
2997 
2998 	elr = ext4_li_request_new(sb, first_not_zeroed);
2999 	if (!elr)
3000 		return -ENOMEM;
3001 
3002 	mutex_lock(&ext4_li_mtx);
3003 
3004 	if (NULL == ext4_li_info) {
3005 		ret = ext4_li_info_new();
3006 		if (ret)
3007 			goto out;
3008 	}
3009 
3010 	mutex_lock(&ext4_li_info->li_list_mtx);
3011 	list_add(&elr->lr_request, &ext4_li_info->li_request_list);
3012 	mutex_unlock(&ext4_li_info->li_list_mtx);
3013 
3014 	sbi->s_li_request = elr;
3015 	/*
3016 	 * set elr to NULL here since it has been inserted to
3017 	 * the request_list and the removal and free of it is
3018 	 * handled by ext4_clear_request_list from now on.
3019 	 */
3020 	elr = NULL;
3021 
3022 	if (!(ext4_li_info->li_state & EXT4_LAZYINIT_RUNNING)) {
3023 		ret = ext4_run_lazyinit_thread();
3024 		if (ret)
3025 			goto out;
3026 	}
3027 out:
3028 	mutex_unlock(&ext4_li_mtx);
3029 	if (ret)
3030 		kfree(elr);
3031 	return ret;
3032 }
3033 
3034 /*
3035  * We do not need to lock anything since this is called on
3036  * module unload.
3037  */
3038 static void ext4_destroy_lazyinit_thread(void)
3039 {
3040 	/*
3041 	 * If thread exited earlier
3042 	 * there's nothing to be done.
3043 	 */
3044 	if (!ext4_li_info || !ext4_lazyinit_task)
3045 		return;
3046 
3047 	kthread_stop(ext4_lazyinit_task);
3048 }
3049 
3050 static int set_journal_csum_feature_set(struct super_block *sb)
3051 {
3052 	int ret = 1;
3053 	int compat, incompat;
3054 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3055 
3056 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3057 				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
3058 		/* journal checksum v2 */
3059 		compat = 0;
3060 		incompat = JBD2_FEATURE_INCOMPAT_CSUM_V2;
3061 	} else {
3062 		/* journal checksum v1 */
3063 		compat = JBD2_FEATURE_COMPAT_CHECKSUM;
3064 		incompat = 0;
3065 	}
3066 
3067 	if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
3068 		ret = jbd2_journal_set_features(sbi->s_journal,
3069 				compat, 0,
3070 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT |
3071 				incompat);
3072 	} else if (test_opt(sb, JOURNAL_CHECKSUM)) {
3073 		ret = jbd2_journal_set_features(sbi->s_journal,
3074 				compat, 0,
3075 				incompat);
3076 		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
3077 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
3078 	} else {
3079 		jbd2_journal_clear_features(sbi->s_journal,
3080 				JBD2_FEATURE_COMPAT_CHECKSUM, 0,
3081 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT |
3082 				JBD2_FEATURE_INCOMPAT_CSUM_V2);
3083 	}
3084 
3085 	return ret;
3086 }
3087 
3088 static int ext4_fill_super(struct super_block *sb, void *data, int silent)
3089 {
3090 	char *orig_data = kstrdup(data, GFP_KERNEL);
3091 	struct buffer_head *bh;
3092 	struct ext4_super_block *es = NULL;
3093 	struct ext4_sb_info *sbi;
3094 	ext4_fsblk_t block;
3095 	ext4_fsblk_t sb_block = get_sb_block(&data);
3096 	ext4_fsblk_t logical_sb_block;
3097 	unsigned long offset = 0;
3098 	unsigned long journal_devnum = 0;
3099 	unsigned long def_mount_opts;
3100 	struct inode *root;
3101 	char *cp;
3102 	const char *descr;
3103 	int ret = -ENOMEM;
3104 	int blocksize, clustersize;
3105 	unsigned int db_count;
3106 	unsigned int i;
3107 	int needs_recovery, has_huge_files, has_bigalloc;
3108 	__u64 blocks_count;
3109 	int err;
3110 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
3111 	ext4_group_t first_not_zeroed;
3112 
3113 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
3114 	if (!sbi)
3115 		goto out_free_orig;
3116 
3117 	sbi->s_blockgroup_lock =
3118 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
3119 	if (!sbi->s_blockgroup_lock) {
3120 		kfree(sbi);
3121 		goto out_free_orig;
3122 	}
3123 	sb->s_fs_info = sbi;
3124 	sbi->s_sb = sb;
3125 	sbi->s_mount_opt = 0;
3126 	sbi->s_resuid = make_kuid(&init_user_ns, EXT4_DEF_RESUID);
3127 	sbi->s_resgid = make_kgid(&init_user_ns, EXT4_DEF_RESGID);
3128 	sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
3129 	sbi->s_sb_block = sb_block;
3130 	if (sb->s_bdev->bd_part)
3131 		sbi->s_sectors_written_start =
3132 			part_stat_read(sb->s_bdev->bd_part, sectors[1]);
3133 
3134 	/* Cleanup superblock name */
3135 	for (cp = sb->s_id; (cp = strchr(cp, '/'));)
3136 		*cp = '!';
3137 
3138 	ret = -EINVAL;
3139 	blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
3140 	if (!blocksize) {
3141 		ext4_msg(sb, KERN_ERR, "unable to set blocksize");
3142 		goto out_fail;
3143 	}
3144 
3145 	/*
3146 	 * The ext4 superblock will not be buffer aligned for other than 1kB
3147 	 * block sizes.  We need to calculate the offset from buffer start.
3148 	 */
3149 	if (blocksize != EXT4_MIN_BLOCK_SIZE) {
3150 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3151 		offset = do_div(logical_sb_block, blocksize);
3152 	} else {
3153 		logical_sb_block = sb_block;
3154 	}
3155 
3156 	if (!(bh = sb_bread(sb, logical_sb_block))) {
3157 		ext4_msg(sb, KERN_ERR, "unable to read superblock");
3158 		goto out_fail;
3159 	}
3160 	/*
3161 	 * Note: s_es must be initialized as soon as possible because
3162 	 *       some ext4 macro-instructions depend on its value
3163 	 */
3164 	es = (struct ext4_super_block *) (bh->b_data + offset);
3165 	sbi->s_es = es;
3166 	sb->s_magic = le16_to_cpu(es->s_magic);
3167 	if (sb->s_magic != EXT4_SUPER_MAGIC)
3168 		goto cantfind_ext4;
3169 	sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
3170 
3171 	/* Warn if metadata_csum and gdt_csum are both set. */
3172 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3173 				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
3174 	    EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
3175 		ext4_warning(sb, KERN_INFO "metadata_csum and uninit_bg are "
3176 			     "redundant flags; please run fsck.");
3177 
3178 	/* Check for a known checksum algorithm */
3179 	if (!ext4_verify_csum_type(sb, es)) {
3180 		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
3181 			 "unknown checksum algorithm.");
3182 		silent = 1;
3183 		goto cantfind_ext4;
3184 	}
3185 
3186 	/* Load the checksum driver */
3187 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3188 				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
3189 		sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
3190 		if (IS_ERR(sbi->s_chksum_driver)) {
3191 			ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
3192 			ret = PTR_ERR(sbi->s_chksum_driver);
3193 			sbi->s_chksum_driver = NULL;
3194 			goto failed_mount;
3195 		}
3196 	}
3197 
3198 	/* Check superblock checksum */
3199 	if (!ext4_superblock_csum_verify(sb, es)) {
3200 		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
3201 			 "invalid superblock checksum.  Run e2fsck?");
3202 		silent = 1;
3203 		goto cantfind_ext4;
3204 	}
3205 
3206 	/* Precompute checksum seed for all metadata */
3207 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3208 			EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
3209 		sbi->s_csum_seed = ext4_chksum(sbi, ~0, es->s_uuid,
3210 					       sizeof(es->s_uuid));
3211 
3212 	/* Set defaults before we parse the mount options */
3213 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
3214 	set_opt(sb, INIT_INODE_TABLE);
3215 	if (def_mount_opts & EXT4_DEFM_DEBUG)
3216 		set_opt(sb, DEBUG);
3217 	if (def_mount_opts & EXT4_DEFM_BSDGROUPS)
3218 		set_opt(sb, GRPID);
3219 	if (def_mount_opts & EXT4_DEFM_UID16)
3220 		set_opt(sb, NO_UID32);
3221 	/* xattr user namespace & acls are now defaulted on */
3222 #ifdef CONFIG_EXT4_FS_XATTR
3223 	set_opt(sb, XATTR_USER);
3224 #endif
3225 #ifdef CONFIG_EXT4_FS_POSIX_ACL
3226 	set_opt(sb, POSIX_ACL);
3227 #endif
3228 	set_opt(sb, MBLK_IO_SUBMIT);
3229 	if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA)
3230 		set_opt(sb, JOURNAL_DATA);
3231 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_ORDERED)
3232 		set_opt(sb, ORDERED_DATA);
3233 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_WBACK)
3234 		set_opt(sb, WRITEBACK_DATA);
3235 
3236 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_PANIC)
3237 		set_opt(sb, ERRORS_PANIC);
3238 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_CONTINUE)
3239 		set_opt(sb, ERRORS_CONT);
3240 	else
3241 		set_opt(sb, ERRORS_RO);
3242 	if (def_mount_opts & EXT4_DEFM_BLOCK_VALIDITY)
3243 		set_opt(sb, BLOCK_VALIDITY);
3244 	if (def_mount_opts & EXT4_DEFM_DISCARD)
3245 		set_opt(sb, DISCARD);
3246 
3247 	sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
3248 	sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
3249 	sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ;
3250 	sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;
3251 	sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;
3252 
3253 	if ((def_mount_opts & EXT4_DEFM_NOBARRIER) == 0)
3254 		set_opt(sb, BARRIER);
3255 
3256 	/*
3257 	 * enable delayed allocation by default
3258 	 * Use -o nodelalloc to turn it off
3259 	 */
3260 	if (!IS_EXT3_SB(sb) &&
3261 	    ((def_mount_opts & EXT4_DEFM_NODELALLOC) == 0))
3262 		set_opt(sb, DELALLOC);
3263 
3264 	/*
3265 	 * set default s_li_wait_mult for lazyinit, for the case there is
3266 	 * no mount option specified.
3267 	 */
3268 	sbi->s_li_wait_mult = EXT4_DEF_LI_WAIT_MULT;
3269 
3270 	if (!parse_options((char *) sbi->s_es->s_mount_opts, sb,
3271 			   &journal_devnum, &journal_ioprio, 0)) {
3272 		ext4_msg(sb, KERN_WARNING,
3273 			 "failed to parse options in superblock: %s",
3274 			 sbi->s_es->s_mount_opts);
3275 	}
3276 	sbi->s_def_mount_opt = sbi->s_mount_opt;
3277 	if (!parse_options((char *) data, sb, &journal_devnum,
3278 			   &journal_ioprio, 0))
3279 		goto failed_mount;
3280 
3281 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
3282 		printk_once(KERN_WARNING "EXT4-fs: Warning: mounting "
3283 			    "with data=journal disables delayed "
3284 			    "allocation and O_DIRECT support!\n");
3285 		if (test_opt2(sb, EXPLICIT_DELALLOC)) {
3286 			ext4_msg(sb, KERN_ERR, "can't mount with "
3287 				 "both data=journal and delalloc");
3288 			goto failed_mount;
3289 		}
3290 		if (test_opt(sb, DIOREAD_NOLOCK)) {
3291 			ext4_msg(sb, KERN_ERR, "can't mount with "
3292 				 "both data=journal and delalloc");
3293 			goto failed_mount;
3294 		}
3295 		if (test_opt(sb, DELALLOC))
3296 			clear_opt(sb, DELALLOC);
3297 	}
3298 
3299 	blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
3300 	if (test_opt(sb, DIOREAD_NOLOCK)) {
3301 		if (blocksize < PAGE_SIZE) {
3302 			ext4_msg(sb, KERN_ERR, "can't mount with "
3303 				 "dioread_nolock if block size != PAGE_SIZE");
3304 			goto failed_mount;
3305 		}
3306 	}
3307 
3308 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
3309 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
3310 
3311 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
3312 	    (EXT4_HAS_COMPAT_FEATURE(sb, ~0U) ||
3313 	     EXT4_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
3314 	     EXT4_HAS_INCOMPAT_FEATURE(sb, ~0U)))
3315 		ext4_msg(sb, KERN_WARNING,
3316 		       "feature flags set on rev 0 fs, "
3317 		       "running e2fsck is recommended");
3318 
3319 	if (IS_EXT2_SB(sb)) {
3320 		if (ext2_feature_set_ok(sb))
3321 			ext4_msg(sb, KERN_INFO, "mounting ext2 file system "
3322 				 "using the ext4 subsystem");
3323 		else {
3324 			ext4_msg(sb, KERN_ERR, "couldn't mount as ext2 due "
3325 				 "to feature incompatibilities");
3326 			goto failed_mount;
3327 		}
3328 	}
3329 
3330 	if (IS_EXT3_SB(sb)) {
3331 		if (ext3_feature_set_ok(sb))
3332 			ext4_msg(sb, KERN_INFO, "mounting ext3 file system "
3333 				 "using the ext4 subsystem");
3334 		else {
3335 			ext4_msg(sb, KERN_ERR, "couldn't mount as ext3 due "
3336 				 "to feature incompatibilities");
3337 			goto failed_mount;
3338 		}
3339 	}
3340 
3341 	/*
3342 	 * Check feature flags regardless of the revision level, since we
3343 	 * previously didn't change the revision level when setting the flags,
3344 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
3345 	 */
3346 	if (!ext4_feature_set_ok(sb, (sb->s_flags & MS_RDONLY)))
3347 		goto failed_mount;
3348 
3349 	if (blocksize < EXT4_MIN_BLOCK_SIZE ||
3350 	    blocksize > EXT4_MAX_BLOCK_SIZE) {
3351 		ext4_msg(sb, KERN_ERR,
3352 		       "Unsupported filesystem blocksize %d", blocksize);
3353 		goto failed_mount;
3354 	}
3355 
3356 	if (sb->s_blocksize != blocksize) {
3357 		/* Validate the filesystem blocksize */
3358 		if (!sb_set_blocksize(sb, blocksize)) {
3359 			ext4_msg(sb, KERN_ERR, "bad block size %d",
3360 					blocksize);
3361 			goto failed_mount;
3362 		}
3363 
3364 		brelse(bh);
3365 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3366 		offset = do_div(logical_sb_block, blocksize);
3367 		bh = sb_bread(sb, logical_sb_block);
3368 		if (!bh) {
3369 			ext4_msg(sb, KERN_ERR,
3370 			       "Can't read superblock on 2nd try");
3371 			goto failed_mount;
3372 		}
3373 		es = (struct ext4_super_block *)(bh->b_data + offset);
3374 		sbi->s_es = es;
3375 		if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
3376 			ext4_msg(sb, KERN_ERR,
3377 			       "Magic mismatch, very weird!");
3378 			goto failed_mount;
3379 		}
3380 	}
3381 
3382 	has_huge_files = EXT4_HAS_RO_COMPAT_FEATURE(sb,
3383 				EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
3384 	sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits,
3385 						      has_huge_files);
3386 	sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits, has_huge_files);
3387 
3388 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) {
3389 		sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE;
3390 		sbi->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
3391 	} else {
3392 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
3393 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
3394 		if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
3395 		    (!is_power_of_2(sbi->s_inode_size)) ||
3396 		    (sbi->s_inode_size > blocksize)) {
3397 			ext4_msg(sb, KERN_ERR,
3398 			       "unsupported inode size: %d",
3399 			       sbi->s_inode_size);
3400 			goto failed_mount;
3401 		}
3402 		if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE)
3403 			sb->s_time_gran = 1 << (EXT4_EPOCH_BITS - 2);
3404 	}
3405 
3406 	sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
3407 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT)) {
3408 		if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT ||
3409 		    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
3410 		    !is_power_of_2(sbi->s_desc_size)) {
3411 			ext4_msg(sb, KERN_ERR,
3412 			       "unsupported descriptor size %lu",
3413 			       sbi->s_desc_size);
3414 			goto failed_mount;
3415 		}
3416 	} else
3417 		sbi->s_desc_size = EXT4_MIN_DESC_SIZE;
3418 
3419 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
3420 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
3421 	if (EXT4_INODE_SIZE(sb) == 0 || EXT4_INODES_PER_GROUP(sb) == 0)
3422 		goto cantfind_ext4;
3423 
3424 	sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
3425 	if (sbi->s_inodes_per_block == 0)
3426 		goto cantfind_ext4;
3427 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
3428 					sbi->s_inodes_per_block;
3429 	sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
3430 	sbi->s_sbh = bh;
3431 	sbi->s_mount_state = le16_to_cpu(es->s_state);
3432 	sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
3433 	sbi->s_desc_per_block_bits = ilog2(EXT4_DESC_PER_BLOCK(sb));
3434 
3435 	for (i = 0; i < 4; i++)
3436 		sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
3437 	sbi->s_def_hash_version = es->s_def_hash_version;
3438 	i = le32_to_cpu(es->s_flags);
3439 	if (i & EXT2_FLAGS_UNSIGNED_HASH)
3440 		sbi->s_hash_unsigned = 3;
3441 	else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) {
3442 #ifdef __CHAR_UNSIGNED__
3443 		es->s_flags |= cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH);
3444 		sbi->s_hash_unsigned = 3;
3445 #else
3446 		es->s_flags |= cpu_to_le32(EXT2_FLAGS_SIGNED_HASH);
3447 #endif
3448 	}
3449 
3450 	/* Handle clustersize */
3451 	clustersize = BLOCK_SIZE << le32_to_cpu(es->s_log_cluster_size);
3452 	has_bigalloc = EXT4_HAS_RO_COMPAT_FEATURE(sb,
3453 				EXT4_FEATURE_RO_COMPAT_BIGALLOC);
3454 	if (has_bigalloc) {
3455 		if (clustersize < blocksize) {
3456 			ext4_msg(sb, KERN_ERR,
3457 				 "cluster size (%d) smaller than "
3458 				 "block size (%d)", clustersize, blocksize);
3459 			goto failed_mount;
3460 		}
3461 		sbi->s_cluster_bits = le32_to_cpu(es->s_log_cluster_size) -
3462 			le32_to_cpu(es->s_log_block_size);
3463 		sbi->s_clusters_per_group =
3464 			le32_to_cpu(es->s_clusters_per_group);
3465 		if (sbi->s_clusters_per_group > blocksize * 8) {
3466 			ext4_msg(sb, KERN_ERR,
3467 				 "#clusters per group too big: %lu",
3468 				 sbi->s_clusters_per_group);
3469 			goto failed_mount;
3470 		}
3471 		if (sbi->s_blocks_per_group !=
3472 		    (sbi->s_clusters_per_group * (clustersize / blocksize))) {
3473 			ext4_msg(sb, KERN_ERR, "blocks per group (%lu) and "
3474 				 "clusters per group (%lu) inconsistent",
3475 				 sbi->s_blocks_per_group,
3476 				 sbi->s_clusters_per_group);
3477 			goto failed_mount;
3478 		}
3479 	} else {
3480 		if (clustersize != blocksize) {
3481 			ext4_warning(sb, "fragment/cluster size (%d) != "
3482 				     "block size (%d)", clustersize,
3483 				     blocksize);
3484 			clustersize = blocksize;
3485 		}
3486 		if (sbi->s_blocks_per_group > blocksize * 8) {
3487 			ext4_msg(sb, KERN_ERR,
3488 				 "#blocks per group too big: %lu",
3489 				 sbi->s_blocks_per_group);
3490 			goto failed_mount;
3491 		}
3492 		sbi->s_clusters_per_group = sbi->s_blocks_per_group;
3493 		sbi->s_cluster_bits = 0;
3494 	}
3495 	sbi->s_cluster_ratio = clustersize / blocksize;
3496 
3497 	if (sbi->s_inodes_per_group > blocksize * 8) {
3498 		ext4_msg(sb, KERN_ERR,
3499 		       "#inodes per group too big: %lu",
3500 		       sbi->s_inodes_per_group);
3501 		goto failed_mount;
3502 	}
3503 
3504 	/*
3505 	 * Test whether we have more sectors than will fit in sector_t,
3506 	 * and whether the max offset is addressable by the page cache.
3507 	 */
3508 	err = generic_check_addressable(sb->s_blocksize_bits,
3509 					ext4_blocks_count(es));
3510 	if (err) {
3511 		ext4_msg(sb, KERN_ERR, "filesystem"
3512 			 " too large to mount safely on this system");
3513 		if (sizeof(sector_t) < 8)
3514 			ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled");
3515 		ret = err;
3516 		goto failed_mount;
3517 	}
3518 
3519 	if (EXT4_BLOCKS_PER_GROUP(sb) == 0)
3520 		goto cantfind_ext4;
3521 
3522 	/* check blocks count against device size */
3523 	blocks_count = sb->s_bdev->bd_inode->i_size >> sb->s_blocksize_bits;
3524 	if (blocks_count && ext4_blocks_count(es) > blocks_count) {
3525 		ext4_msg(sb, KERN_WARNING, "bad geometry: block count %llu "
3526 		       "exceeds size of device (%llu blocks)",
3527 		       ext4_blocks_count(es), blocks_count);
3528 		goto failed_mount;
3529 	}
3530 
3531 	/*
3532 	 * It makes no sense for the first data block to be beyond the end
3533 	 * of the filesystem.
3534 	 */
3535 	if (le32_to_cpu(es->s_first_data_block) >= ext4_blocks_count(es)) {
3536 		ext4_msg(sb, KERN_WARNING, "bad geometry: first data "
3537 			 "block %u is beyond end of filesystem (%llu)",
3538 			 le32_to_cpu(es->s_first_data_block),
3539 			 ext4_blocks_count(es));
3540 		goto failed_mount;
3541 	}
3542 	blocks_count = (ext4_blocks_count(es) -
3543 			le32_to_cpu(es->s_first_data_block) +
3544 			EXT4_BLOCKS_PER_GROUP(sb) - 1);
3545 	do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
3546 	if (blocks_count > ((uint64_t)1<<32) - EXT4_DESC_PER_BLOCK(sb)) {
3547 		ext4_msg(sb, KERN_WARNING, "groups count too large: %u "
3548 		       "(block count %llu, first data block %u, "
3549 		       "blocks per group %lu)", sbi->s_groups_count,
3550 		       ext4_blocks_count(es),
3551 		       le32_to_cpu(es->s_first_data_block),
3552 		       EXT4_BLOCKS_PER_GROUP(sb));
3553 		goto failed_mount;
3554 	}
3555 	sbi->s_groups_count = blocks_count;
3556 	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
3557 			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
3558 	db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
3559 		   EXT4_DESC_PER_BLOCK(sb);
3560 	sbi->s_group_desc = ext4_kvmalloc(db_count *
3561 					  sizeof(struct buffer_head *),
3562 					  GFP_KERNEL);
3563 	if (sbi->s_group_desc == NULL) {
3564 		ext4_msg(sb, KERN_ERR, "not enough memory");
3565 		ret = -ENOMEM;
3566 		goto failed_mount;
3567 	}
3568 
3569 	if (ext4_proc_root)
3570 		sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
3571 
3572 	if (sbi->s_proc)
3573 		proc_create_data("options", S_IRUGO, sbi->s_proc,
3574 				 &ext4_seq_options_fops, sb);
3575 
3576 	bgl_lock_init(sbi->s_blockgroup_lock);
3577 
3578 	for (i = 0; i < db_count; i++) {
3579 		block = descriptor_loc(sb, logical_sb_block, i);
3580 		sbi->s_group_desc[i] = sb_bread(sb, block);
3581 		if (!sbi->s_group_desc[i]) {
3582 			ext4_msg(sb, KERN_ERR,
3583 			       "can't read group descriptor %d", i);
3584 			db_count = i;
3585 			goto failed_mount2;
3586 		}
3587 	}
3588 	if (!ext4_check_descriptors(sb, &first_not_zeroed)) {
3589 		ext4_msg(sb, KERN_ERR, "group descriptors corrupted!");
3590 		goto failed_mount2;
3591 	}
3592 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
3593 		if (!ext4_fill_flex_info(sb)) {
3594 			ext4_msg(sb, KERN_ERR,
3595 			       "unable to initialize "
3596 			       "flex_bg meta info!");
3597 			goto failed_mount2;
3598 		}
3599 
3600 	sbi->s_gdb_count = db_count;
3601 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
3602 	spin_lock_init(&sbi->s_next_gen_lock);
3603 
3604 	init_timer(&sbi->s_err_report);
3605 	sbi->s_err_report.function = print_daily_error_info;
3606 	sbi->s_err_report.data = (unsigned long) sb;
3607 
3608 	err = percpu_counter_init(&sbi->s_freeclusters_counter,
3609 			ext4_count_free_clusters(sb));
3610 	if (!err) {
3611 		err = percpu_counter_init(&sbi->s_freeinodes_counter,
3612 				ext4_count_free_inodes(sb));
3613 	}
3614 	if (!err) {
3615 		err = percpu_counter_init(&sbi->s_dirs_counter,
3616 				ext4_count_dirs(sb));
3617 	}
3618 	if (!err) {
3619 		err = percpu_counter_init(&sbi->s_dirtyclusters_counter, 0);
3620 	}
3621 	if (err) {
3622 		ext4_msg(sb, KERN_ERR, "insufficient memory");
3623 		ret = err;
3624 		goto failed_mount3;
3625 	}
3626 
3627 	sbi->s_stripe = ext4_get_stripe_size(sbi);
3628 	sbi->s_max_writeback_mb_bump = 128;
3629 
3630 	/*
3631 	 * set up enough so that it can read an inode
3632 	 */
3633 	if (!test_opt(sb, NOLOAD) &&
3634 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL))
3635 		sb->s_op = &ext4_sops;
3636 	else
3637 		sb->s_op = &ext4_nojournal_sops;
3638 	sb->s_export_op = &ext4_export_ops;
3639 	sb->s_xattr = ext4_xattr_handlers;
3640 #ifdef CONFIG_QUOTA
3641 	sb->s_qcop = &ext4_qctl_operations;
3642 	sb->dq_op = &ext4_quota_operations;
3643 #endif
3644 	memcpy(sb->s_uuid, es->s_uuid, sizeof(es->s_uuid));
3645 
3646 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
3647 	mutex_init(&sbi->s_orphan_lock);
3648 	sbi->s_resize_flags = 0;
3649 
3650 	sb->s_root = NULL;
3651 
3652 	needs_recovery = (es->s_last_orphan != 0 ||
3653 			  EXT4_HAS_INCOMPAT_FEATURE(sb,
3654 				    EXT4_FEATURE_INCOMPAT_RECOVER));
3655 
3656 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_MMP) &&
3657 	    !(sb->s_flags & MS_RDONLY))
3658 		if (ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block)))
3659 			goto failed_mount3;
3660 
3661 	/*
3662 	 * The first inode we look at is the journal inode.  Don't try
3663 	 * root first: it may be modified in the journal!
3664 	 */
3665 	if (!test_opt(sb, NOLOAD) &&
3666 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
3667 		if (ext4_load_journal(sb, es, journal_devnum))
3668 			goto failed_mount3;
3669 	} else if (test_opt(sb, NOLOAD) && !(sb->s_flags & MS_RDONLY) &&
3670 	      EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
3671 		ext4_msg(sb, KERN_ERR, "required journal recovery "
3672 		       "suppressed and not mounted read-only");
3673 		goto failed_mount_wq;
3674 	} else {
3675 		clear_opt(sb, DATA_FLAGS);
3676 		sbi->s_journal = NULL;
3677 		needs_recovery = 0;
3678 		goto no_journal;
3679 	}
3680 
3681 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT) &&
3682 	    !jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
3683 				       JBD2_FEATURE_INCOMPAT_64BIT)) {
3684 		ext4_msg(sb, KERN_ERR, "Failed to set 64-bit journal feature");
3685 		goto failed_mount_wq;
3686 	}
3687 
3688 	if (!set_journal_csum_feature_set(sb)) {
3689 		ext4_msg(sb, KERN_ERR, "Failed to set journal checksum "
3690 			 "feature set");
3691 		goto failed_mount_wq;
3692 	}
3693 
3694 	/* We have now updated the journal if required, so we can
3695 	 * validate the data journaling mode. */
3696 	switch (test_opt(sb, DATA_FLAGS)) {
3697 	case 0:
3698 		/* No mode set, assume a default based on the journal
3699 		 * capabilities: ORDERED_DATA if the journal can
3700 		 * cope, else JOURNAL_DATA
3701 		 */
3702 		if (jbd2_journal_check_available_features
3703 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE))
3704 			set_opt(sb, ORDERED_DATA);
3705 		else
3706 			set_opt(sb, JOURNAL_DATA);
3707 		break;
3708 
3709 	case EXT4_MOUNT_ORDERED_DATA:
3710 	case EXT4_MOUNT_WRITEBACK_DATA:
3711 		if (!jbd2_journal_check_available_features
3712 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
3713 			ext4_msg(sb, KERN_ERR, "Journal does not support "
3714 			       "requested data journaling mode");
3715 			goto failed_mount_wq;
3716 		}
3717 	default:
3718 		break;
3719 	}
3720 	set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
3721 
3722 	sbi->s_journal->j_commit_callback = ext4_journal_commit_callback;
3723 
3724 	/*
3725 	 * The journal may have updated the bg summary counts, so we
3726 	 * need to update the global counters.
3727 	 */
3728 	percpu_counter_set(&sbi->s_freeclusters_counter,
3729 			   ext4_count_free_clusters(sb));
3730 	percpu_counter_set(&sbi->s_freeinodes_counter,
3731 			   ext4_count_free_inodes(sb));
3732 	percpu_counter_set(&sbi->s_dirs_counter,
3733 			   ext4_count_dirs(sb));
3734 	percpu_counter_set(&sbi->s_dirtyclusters_counter, 0);
3735 
3736 no_journal:
3737 	/*
3738 	 * The maximum number of concurrent works can be high and
3739 	 * concurrency isn't really necessary.  Limit it to 1.
3740 	 */
3741 	EXT4_SB(sb)->dio_unwritten_wq =
3742 		alloc_workqueue("ext4-dio-unwritten", WQ_MEM_RECLAIM | WQ_UNBOUND, 1);
3743 	if (!EXT4_SB(sb)->dio_unwritten_wq) {
3744 		printk(KERN_ERR "EXT4-fs: failed to create DIO workqueue\n");
3745 		goto failed_mount_wq;
3746 	}
3747 
3748 	/*
3749 	 * The jbd2_journal_load will have done any necessary log recovery,
3750 	 * so we can safely mount the rest of the filesystem now.
3751 	 */
3752 
3753 	root = ext4_iget(sb, EXT4_ROOT_INO);
3754 	if (IS_ERR(root)) {
3755 		ext4_msg(sb, KERN_ERR, "get root inode failed");
3756 		ret = PTR_ERR(root);
3757 		root = NULL;
3758 		goto failed_mount4;
3759 	}
3760 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
3761 		ext4_msg(sb, KERN_ERR, "corrupt root inode, run e2fsck");
3762 		iput(root);
3763 		goto failed_mount4;
3764 	}
3765 	sb->s_root = d_make_root(root);
3766 	if (!sb->s_root) {
3767 		ext4_msg(sb, KERN_ERR, "get root dentry failed");
3768 		ret = -ENOMEM;
3769 		goto failed_mount4;
3770 	}
3771 
3772 	if (ext4_setup_super(sb, es, sb->s_flags & MS_RDONLY))
3773 		sb->s_flags |= MS_RDONLY;
3774 
3775 	/* determine the minimum size of new large inodes, if present */
3776 	if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
3777 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
3778 						     EXT4_GOOD_OLD_INODE_SIZE;
3779 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3780 				       EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE)) {
3781 			if (sbi->s_want_extra_isize <
3782 			    le16_to_cpu(es->s_want_extra_isize))
3783 				sbi->s_want_extra_isize =
3784 					le16_to_cpu(es->s_want_extra_isize);
3785 			if (sbi->s_want_extra_isize <
3786 			    le16_to_cpu(es->s_min_extra_isize))
3787 				sbi->s_want_extra_isize =
3788 					le16_to_cpu(es->s_min_extra_isize);
3789 		}
3790 	}
3791 	/* Check if enough inode space is available */
3792 	if (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize >
3793 							sbi->s_inode_size) {
3794 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
3795 						       EXT4_GOOD_OLD_INODE_SIZE;
3796 		ext4_msg(sb, KERN_INFO, "required extra inode space not"
3797 			 "available");
3798 	}
3799 
3800 	err = ext4_setup_system_zone(sb);
3801 	if (err) {
3802 		ext4_msg(sb, KERN_ERR, "failed to initialize system "
3803 			 "zone (%d)", err);
3804 		goto failed_mount4a;
3805 	}
3806 
3807 	ext4_ext_init(sb);
3808 	err = ext4_mb_init(sb);
3809 	if (err) {
3810 		ext4_msg(sb, KERN_ERR, "failed to initialize mballoc (%d)",
3811 			 err);
3812 		goto failed_mount5;
3813 	}
3814 
3815 	err = ext4_register_li_request(sb, first_not_zeroed);
3816 	if (err)
3817 		goto failed_mount6;
3818 
3819 	sbi->s_kobj.kset = ext4_kset;
3820 	init_completion(&sbi->s_kobj_unregister);
3821 	err = kobject_init_and_add(&sbi->s_kobj, &ext4_ktype, NULL,
3822 				   "%s", sb->s_id);
3823 	if (err)
3824 		goto failed_mount7;
3825 
3826 	EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
3827 	ext4_orphan_cleanup(sb, es);
3828 	EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
3829 	if (needs_recovery) {
3830 		ext4_msg(sb, KERN_INFO, "recovery complete");
3831 		ext4_mark_recovery_complete(sb, es);
3832 	}
3833 	if (EXT4_SB(sb)->s_journal) {
3834 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
3835 			descr = " journalled data mode";
3836 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
3837 			descr = " ordered data mode";
3838 		else
3839 			descr = " writeback data mode";
3840 	} else
3841 		descr = "out journal";
3842 
3843 	ext4_msg(sb, KERN_INFO, "mounted filesystem with%s. "
3844 		 "Opts: %s%s%s", descr, sbi->s_es->s_mount_opts,
3845 		 *sbi->s_es->s_mount_opts ? "; " : "", orig_data);
3846 
3847 	if (es->s_error_count)
3848 		mod_timer(&sbi->s_err_report, jiffies + 300*HZ); /* 5 minutes */
3849 
3850 	kfree(orig_data);
3851 	return 0;
3852 
3853 cantfind_ext4:
3854 	if (!silent)
3855 		ext4_msg(sb, KERN_ERR, "VFS: Can't find ext4 filesystem");
3856 	goto failed_mount;
3857 
3858 failed_mount7:
3859 	ext4_unregister_li_request(sb);
3860 failed_mount6:
3861 	ext4_mb_release(sb);
3862 failed_mount5:
3863 	ext4_ext_release(sb);
3864 	ext4_release_system_zone(sb);
3865 failed_mount4a:
3866 	dput(sb->s_root);
3867 	sb->s_root = NULL;
3868 failed_mount4:
3869 	ext4_msg(sb, KERN_ERR, "mount failed");
3870 	destroy_workqueue(EXT4_SB(sb)->dio_unwritten_wq);
3871 failed_mount_wq:
3872 	if (sbi->s_journal) {
3873 		jbd2_journal_destroy(sbi->s_journal);
3874 		sbi->s_journal = NULL;
3875 	}
3876 failed_mount3:
3877 	del_timer(&sbi->s_err_report);
3878 	if (sbi->s_flex_groups)
3879 		ext4_kvfree(sbi->s_flex_groups);
3880 	percpu_counter_destroy(&sbi->s_freeclusters_counter);
3881 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
3882 	percpu_counter_destroy(&sbi->s_dirs_counter);
3883 	percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
3884 	if (sbi->s_mmp_tsk)
3885 		kthread_stop(sbi->s_mmp_tsk);
3886 failed_mount2:
3887 	for (i = 0; i < db_count; i++)
3888 		brelse(sbi->s_group_desc[i]);
3889 	ext4_kvfree(sbi->s_group_desc);
3890 failed_mount:
3891 	if (sbi->s_chksum_driver)
3892 		crypto_free_shash(sbi->s_chksum_driver);
3893 	if (sbi->s_proc) {
3894 		remove_proc_entry("options", sbi->s_proc);
3895 		remove_proc_entry(sb->s_id, ext4_proc_root);
3896 	}
3897 #ifdef CONFIG_QUOTA
3898 	for (i = 0; i < MAXQUOTAS; i++)
3899 		kfree(sbi->s_qf_names[i]);
3900 #endif
3901 	ext4_blkdev_remove(sbi);
3902 	brelse(bh);
3903 out_fail:
3904 	sb->s_fs_info = NULL;
3905 	kfree(sbi->s_blockgroup_lock);
3906 	kfree(sbi);
3907 out_free_orig:
3908 	kfree(orig_data);
3909 	return ret;
3910 }
3911 
3912 /*
3913  * Setup any per-fs journal parameters now.  We'll do this both on
3914  * initial mount, once the journal has been initialised but before we've
3915  * done any recovery; and again on any subsequent remount.
3916  */
3917 static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
3918 {
3919 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3920 
3921 	journal->j_commit_interval = sbi->s_commit_interval;
3922 	journal->j_min_batch_time = sbi->s_min_batch_time;
3923 	journal->j_max_batch_time = sbi->s_max_batch_time;
3924 
3925 	write_lock(&journal->j_state_lock);
3926 	if (test_opt(sb, BARRIER))
3927 		journal->j_flags |= JBD2_BARRIER;
3928 	else
3929 		journal->j_flags &= ~JBD2_BARRIER;
3930 	if (test_opt(sb, DATA_ERR_ABORT))
3931 		journal->j_flags |= JBD2_ABORT_ON_SYNCDATA_ERR;
3932 	else
3933 		journal->j_flags &= ~JBD2_ABORT_ON_SYNCDATA_ERR;
3934 	write_unlock(&journal->j_state_lock);
3935 }
3936 
3937 static journal_t *ext4_get_journal(struct super_block *sb,
3938 				   unsigned int journal_inum)
3939 {
3940 	struct inode *journal_inode;
3941 	journal_t *journal;
3942 
3943 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
3944 
3945 	/* First, test for the existence of a valid inode on disk.  Bad
3946 	 * things happen if we iget() an unused inode, as the subsequent
3947 	 * iput() will try to delete it. */
3948 
3949 	journal_inode = ext4_iget(sb, journal_inum);
3950 	if (IS_ERR(journal_inode)) {
3951 		ext4_msg(sb, KERN_ERR, "no journal found");
3952 		return NULL;
3953 	}
3954 	if (!journal_inode->i_nlink) {
3955 		make_bad_inode(journal_inode);
3956 		iput(journal_inode);
3957 		ext4_msg(sb, KERN_ERR, "journal inode is deleted");
3958 		return NULL;
3959 	}
3960 
3961 	jbd_debug(2, "Journal inode found at %p: %lld bytes\n",
3962 		  journal_inode, journal_inode->i_size);
3963 	if (!S_ISREG(journal_inode->i_mode)) {
3964 		ext4_msg(sb, KERN_ERR, "invalid journal inode");
3965 		iput(journal_inode);
3966 		return NULL;
3967 	}
3968 
3969 	journal = jbd2_journal_init_inode(journal_inode);
3970 	if (!journal) {
3971 		ext4_msg(sb, KERN_ERR, "Could not load journal inode");
3972 		iput(journal_inode);
3973 		return NULL;
3974 	}
3975 	journal->j_private = sb;
3976 	ext4_init_journal_params(sb, journal);
3977 	return journal;
3978 }
3979 
3980 static journal_t *ext4_get_dev_journal(struct super_block *sb,
3981 				       dev_t j_dev)
3982 {
3983 	struct buffer_head *bh;
3984 	journal_t *journal;
3985 	ext4_fsblk_t start;
3986 	ext4_fsblk_t len;
3987 	int hblock, blocksize;
3988 	ext4_fsblk_t sb_block;
3989 	unsigned long offset;
3990 	struct ext4_super_block *es;
3991 	struct block_device *bdev;
3992 
3993 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
3994 
3995 	bdev = ext4_blkdev_get(j_dev, sb);
3996 	if (bdev == NULL)
3997 		return NULL;
3998 
3999 	blocksize = sb->s_blocksize;
4000 	hblock = bdev_logical_block_size(bdev);
4001 	if (blocksize < hblock) {
4002 		ext4_msg(sb, KERN_ERR,
4003 			"blocksize too small for journal device");
4004 		goto out_bdev;
4005 	}
4006 
4007 	sb_block = EXT4_MIN_BLOCK_SIZE / blocksize;
4008 	offset = EXT4_MIN_BLOCK_SIZE % blocksize;
4009 	set_blocksize(bdev, blocksize);
4010 	if (!(bh = __bread(bdev, sb_block, blocksize))) {
4011 		ext4_msg(sb, KERN_ERR, "couldn't read superblock of "
4012 		       "external journal");
4013 		goto out_bdev;
4014 	}
4015 
4016 	es = (struct ext4_super_block *) (bh->b_data + offset);
4017 	if ((le16_to_cpu(es->s_magic) != EXT4_SUPER_MAGIC) ||
4018 	    !(le32_to_cpu(es->s_feature_incompat) &
4019 	      EXT4_FEATURE_INCOMPAT_JOURNAL_DEV)) {
4020 		ext4_msg(sb, KERN_ERR, "external journal has "
4021 					"bad superblock");
4022 		brelse(bh);
4023 		goto out_bdev;
4024 	}
4025 
4026 	if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
4027 		ext4_msg(sb, KERN_ERR, "journal UUID does not match");
4028 		brelse(bh);
4029 		goto out_bdev;
4030 	}
4031 
4032 	len = ext4_blocks_count(es);
4033 	start = sb_block + 1;
4034 	brelse(bh);	/* we're done with the superblock */
4035 
4036 	journal = jbd2_journal_init_dev(bdev, sb->s_bdev,
4037 					start, len, blocksize);
4038 	if (!journal) {
4039 		ext4_msg(sb, KERN_ERR, "failed to create device journal");
4040 		goto out_bdev;
4041 	}
4042 	journal->j_private = sb;
4043 	ll_rw_block(READ, 1, &journal->j_sb_buffer);
4044 	wait_on_buffer(journal->j_sb_buffer);
4045 	if (!buffer_uptodate(journal->j_sb_buffer)) {
4046 		ext4_msg(sb, KERN_ERR, "I/O error on journal device");
4047 		goto out_journal;
4048 	}
4049 	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
4050 		ext4_msg(sb, KERN_ERR, "External journal has more than one "
4051 					"user (unsupported) - %d",
4052 			be32_to_cpu(journal->j_superblock->s_nr_users));
4053 		goto out_journal;
4054 	}
4055 	EXT4_SB(sb)->journal_bdev = bdev;
4056 	ext4_init_journal_params(sb, journal);
4057 	return journal;
4058 
4059 out_journal:
4060 	jbd2_journal_destroy(journal);
4061 out_bdev:
4062 	ext4_blkdev_put(bdev);
4063 	return NULL;
4064 }
4065 
4066 static int ext4_load_journal(struct super_block *sb,
4067 			     struct ext4_super_block *es,
4068 			     unsigned long journal_devnum)
4069 {
4070 	journal_t *journal;
4071 	unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
4072 	dev_t journal_dev;
4073 	int err = 0;
4074 	int really_read_only;
4075 
4076 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4077 
4078 	if (journal_devnum &&
4079 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
4080 		ext4_msg(sb, KERN_INFO, "external journal device major/minor "
4081 			"numbers have changed");
4082 		journal_dev = new_decode_dev(journal_devnum);
4083 	} else
4084 		journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));
4085 
4086 	really_read_only = bdev_read_only(sb->s_bdev);
4087 
4088 	/*
4089 	 * Are we loading a blank journal or performing recovery after a
4090 	 * crash?  For recovery, we need to check in advance whether we
4091 	 * can get read-write access to the device.
4092 	 */
4093 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
4094 		if (sb->s_flags & MS_RDONLY) {
4095 			ext4_msg(sb, KERN_INFO, "INFO: recovery "
4096 					"required on readonly filesystem");
4097 			if (really_read_only) {
4098 				ext4_msg(sb, KERN_ERR, "write access "
4099 					"unavailable, cannot proceed");
4100 				return -EROFS;
4101 			}
4102 			ext4_msg(sb, KERN_INFO, "write access will "
4103 			       "be enabled during recovery");
4104 		}
4105 	}
4106 
4107 	if (journal_inum && journal_dev) {
4108 		ext4_msg(sb, KERN_ERR, "filesystem has both journal "
4109 		       "and inode journals!");
4110 		return -EINVAL;
4111 	}
4112 
4113 	if (journal_inum) {
4114 		if (!(journal = ext4_get_journal(sb, journal_inum)))
4115 			return -EINVAL;
4116 	} else {
4117 		if (!(journal = ext4_get_dev_journal(sb, journal_dev)))
4118 			return -EINVAL;
4119 	}
4120 
4121 	if (!(journal->j_flags & JBD2_BARRIER))
4122 		ext4_msg(sb, KERN_INFO, "barriers disabled");
4123 
4124 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER))
4125 		err = jbd2_journal_wipe(journal, !really_read_only);
4126 	if (!err) {
4127 		char *save = kmalloc(EXT4_S_ERR_LEN, GFP_KERNEL);
4128 		if (save)
4129 			memcpy(save, ((char *) es) +
4130 			       EXT4_S_ERR_START, EXT4_S_ERR_LEN);
4131 		err = jbd2_journal_load(journal);
4132 		if (save)
4133 			memcpy(((char *) es) + EXT4_S_ERR_START,
4134 			       save, EXT4_S_ERR_LEN);
4135 		kfree(save);
4136 	}
4137 
4138 	if (err) {
4139 		ext4_msg(sb, KERN_ERR, "error loading journal");
4140 		jbd2_journal_destroy(journal);
4141 		return err;
4142 	}
4143 
4144 	EXT4_SB(sb)->s_journal = journal;
4145 	ext4_clear_journal_err(sb, es);
4146 
4147 	if (!really_read_only && journal_devnum &&
4148 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
4149 		es->s_journal_dev = cpu_to_le32(journal_devnum);
4150 
4151 		/* Make sure we flush the recovery flag to disk. */
4152 		ext4_commit_super(sb, 1);
4153 	}
4154 
4155 	return 0;
4156 }
4157 
4158 static int ext4_commit_super(struct super_block *sb, int sync)
4159 {
4160 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
4161 	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
4162 	int error = 0;
4163 
4164 	if (!sbh || block_device_ejected(sb))
4165 		return error;
4166 	if (buffer_write_io_error(sbh)) {
4167 		/*
4168 		 * Oh, dear.  A previous attempt to write the
4169 		 * superblock failed.  This could happen because the
4170 		 * USB device was yanked out.  Or it could happen to
4171 		 * be a transient write error and maybe the block will
4172 		 * be remapped.  Nothing we can do but to retry the
4173 		 * write and hope for the best.
4174 		 */
4175 		ext4_msg(sb, KERN_ERR, "previous I/O error to "
4176 		       "superblock detected");
4177 		clear_buffer_write_io_error(sbh);
4178 		set_buffer_uptodate(sbh);
4179 	}
4180 	/*
4181 	 * If the file system is mounted read-only, don't update the
4182 	 * superblock write time.  This avoids updating the superblock
4183 	 * write time when we are mounting the root file system
4184 	 * read/only but we need to replay the journal; at that point,
4185 	 * for people who are east of GMT and who make their clock
4186 	 * tick in localtime for Windows bug-for-bug compatibility,
4187 	 * the clock is set in the future, and this will cause e2fsck
4188 	 * to complain and force a full file system check.
4189 	 */
4190 	if (!(sb->s_flags & MS_RDONLY))
4191 		es->s_wtime = cpu_to_le32(get_seconds());
4192 	if (sb->s_bdev->bd_part)
4193 		es->s_kbytes_written =
4194 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written +
4195 			    ((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
4196 			      EXT4_SB(sb)->s_sectors_written_start) >> 1));
4197 	else
4198 		es->s_kbytes_written =
4199 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written);
4200 	ext4_free_blocks_count_set(es,
4201 			EXT4_C2B(EXT4_SB(sb), percpu_counter_sum_positive(
4202 				&EXT4_SB(sb)->s_freeclusters_counter)));
4203 	es->s_free_inodes_count =
4204 		cpu_to_le32(percpu_counter_sum_positive(
4205 				&EXT4_SB(sb)->s_freeinodes_counter));
4206 	sb->s_dirt = 0;
4207 	BUFFER_TRACE(sbh, "marking dirty");
4208 	ext4_superblock_csum_set(sb, es);
4209 	mark_buffer_dirty(sbh);
4210 	if (sync) {
4211 		error = sync_dirty_buffer(sbh);
4212 		if (error)
4213 			return error;
4214 
4215 		error = buffer_write_io_error(sbh);
4216 		if (error) {
4217 			ext4_msg(sb, KERN_ERR, "I/O error while writing "
4218 			       "superblock");
4219 			clear_buffer_write_io_error(sbh);
4220 			set_buffer_uptodate(sbh);
4221 		}
4222 	}
4223 	return error;
4224 }
4225 
4226 /*
4227  * Have we just finished recovery?  If so, and if we are mounting (or
4228  * remounting) the filesystem readonly, then we will end up with a
4229  * consistent fs on disk.  Record that fact.
4230  */
4231 static void ext4_mark_recovery_complete(struct super_block *sb,
4232 					struct ext4_super_block *es)
4233 {
4234 	journal_t *journal = EXT4_SB(sb)->s_journal;
4235 
4236 	if (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
4237 		BUG_ON(journal != NULL);
4238 		return;
4239 	}
4240 	jbd2_journal_lock_updates(journal);
4241 	if (jbd2_journal_flush(journal) < 0)
4242 		goto out;
4243 
4244 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER) &&
4245 	    sb->s_flags & MS_RDONLY) {
4246 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4247 		ext4_commit_super(sb, 1);
4248 	}
4249 
4250 out:
4251 	jbd2_journal_unlock_updates(journal);
4252 }
4253 
4254 /*
4255  * If we are mounting (or read-write remounting) a filesystem whose journal
4256  * has recorded an error from a previous lifetime, move that error to the
4257  * main filesystem now.
4258  */
4259 static void ext4_clear_journal_err(struct super_block *sb,
4260 				   struct ext4_super_block *es)
4261 {
4262 	journal_t *journal;
4263 	int j_errno;
4264 	const char *errstr;
4265 
4266 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4267 
4268 	journal = EXT4_SB(sb)->s_journal;
4269 
4270 	/*
4271 	 * Now check for any error status which may have been recorded in the
4272 	 * journal by a prior ext4_error() or ext4_abort()
4273 	 */
4274 
4275 	j_errno = jbd2_journal_errno(journal);
4276 	if (j_errno) {
4277 		char nbuf[16];
4278 
4279 		errstr = ext4_decode_error(sb, j_errno, nbuf);
4280 		ext4_warning(sb, "Filesystem error recorded "
4281 			     "from previous mount: %s", errstr);
4282 		ext4_warning(sb, "Marking fs in need of filesystem check.");
4283 
4284 		EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
4285 		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
4286 		ext4_commit_super(sb, 1);
4287 
4288 		jbd2_journal_clear_err(journal);
4289 	}
4290 }
4291 
4292 /*
4293  * Force the running and committing transactions to commit,
4294  * and wait on the commit.
4295  */
4296 int ext4_force_commit(struct super_block *sb)
4297 {
4298 	journal_t *journal;
4299 	int ret = 0;
4300 
4301 	if (sb->s_flags & MS_RDONLY)
4302 		return 0;
4303 
4304 	journal = EXT4_SB(sb)->s_journal;
4305 	if (journal) {
4306 		vfs_check_frozen(sb, SB_FREEZE_TRANS);
4307 		ret = ext4_journal_force_commit(journal);
4308 	}
4309 
4310 	return ret;
4311 }
4312 
4313 static void ext4_write_super(struct super_block *sb)
4314 {
4315 	lock_super(sb);
4316 	ext4_commit_super(sb, 1);
4317 	unlock_super(sb);
4318 }
4319 
4320 static int ext4_sync_fs(struct super_block *sb, int wait)
4321 {
4322 	int ret = 0;
4323 	tid_t target;
4324 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4325 
4326 	trace_ext4_sync_fs(sb, wait);
4327 	flush_workqueue(sbi->dio_unwritten_wq);
4328 	if (jbd2_journal_start_commit(sbi->s_journal, &target)) {
4329 		if (wait)
4330 			jbd2_log_wait_commit(sbi->s_journal, target);
4331 	}
4332 	return ret;
4333 }
4334 
4335 /*
4336  * LVM calls this function before a (read-only) snapshot is created.  This
4337  * gives us a chance to flush the journal completely and mark the fs clean.
4338  *
4339  * Note that only this function cannot bring a filesystem to be in a clean
4340  * state independently, because ext4 prevents a new handle from being started
4341  * by @sb->s_frozen, which stays in an upper layer.  It thus needs help from
4342  * the upper layer.
4343  */
4344 static int ext4_freeze(struct super_block *sb)
4345 {
4346 	int error = 0;
4347 	journal_t *journal;
4348 
4349 	if (sb->s_flags & MS_RDONLY)
4350 		return 0;
4351 
4352 	journal = EXT4_SB(sb)->s_journal;
4353 
4354 	/* Now we set up the journal barrier. */
4355 	jbd2_journal_lock_updates(journal);
4356 
4357 	/*
4358 	 * Don't clear the needs_recovery flag if we failed to flush
4359 	 * the journal.
4360 	 */
4361 	error = jbd2_journal_flush(journal);
4362 	if (error < 0)
4363 		goto out;
4364 
4365 	/* Journal blocked and flushed, clear needs_recovery flag. */
4366 	EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4367 	error = ext4_commit_super(sb, 1);
4368 out:
4369 	/* we rely on s_frozen to stop further updates */
4370 	jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
4371 	return error;
4372 }
4373 
4374 /*
4375  * Called by LVM after the snapshot is done.  We need to reset the RECOVER
4376  * flag here, even though the filesystem is not technically dirty yet.
4377  */
4378 static int ext4_unfreeze(struct super_block *sb)
4379 {
4380 	if (sb->s_flags & MS_RDONLY)
4381 		return 0;
4382 
4383 	lock_super(sb);
4384 	/* Reset the needs_recovery flag before the fs is unlocked. */
4385 	EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4386 	ext4_commit_super(sb, 1);
4387 	unlock_super(sb);
4388 	return 0;
4389 }
4390 
4391 /*
4392  * Structure to save mount options for ext4_remount's benefit
4393  */
4394 struct ext4_mount_options {
4395 	unsigned long s_mount_opt;
4396 	unsigned long s_mount_opt2;
4397 	kuid_t s_resuid;
4398 	kgid_t s_resgid;
4399 	unsigned long s_commit_interval;
4400 	u32 s_min_batch_time, s_max_batch_time;
4401 #ifdef CONFIG_QUOTA
4402 	int s_jquota_fmt;
4403 	char *s_qf_names[MAXQUOTAS];
4404 #endif
4405 };
4406 
4407 static int ext4_remount(struct super_block *sb, int *flags, char *data)
4408 {
4409 	struct ext4_super_block *es;
4410 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4411 	unsigned long old_sb_flags;
4412 	struct ext4_mount_options old_opts;
4413 	int enable_quota = 0;
4414 	ext4_group_t g;
4415 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
4416 	int err = 0;
4417 #ifdef CONFIG_QUOTA
4418 	int i;
4419 #endif
4420 	char *orig_data = kstrdup(data, GFP_KERNEL);
4421 
4422 	/* Store the original options */
4423 	lock_super(sb);
4424 	old_sb_flags = sb->s_flags;
4425 	old_opts.s_mount_opt = sbi->s_mount_opt;
4426 	old_opts.s_mount_opt2 = sbi->s_mount_opt2;
4427 	old_opts.s_resuid = sbi->s_resuid;
4428 	old_opts.s_resgid = sbi->s_resgid;
4429 	old_opts.s_commit_interval = sbi->s_commit_interval;
4430 	old_opts.s_min_batch_time = sbi->s_min_batch_time;
4431 	old_opts.s_max_batch_time = sbi->s_max_batch_time;
4432 #ifdef CONFIG_QUOTA
4433 	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
4434 	for (i = 0; i < MAXQUOTAS; i++)
4435 		old_opts.s_qf_names[i] = sbi->s_qf_names[i];
4436 #endif
4437 	if (sbi->s_journal && sbi->s_journal->j_task->io_context)
4438 		journal_ioprio = sbi->s_journal->j_task->io_context->ioprio;
4439 
4440 	/*
4441 	 * Allow the "check" option to be passed as a remount option.
4442 	 */
4443 	if (!parse_options(data, sb, NULL, &journal_ioprio, 1)) {
4444 		err = -EINVAL;
4445 		goto restore_opts;
4446 	}
4447 
4448 	if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
4449 		ext4_abort(sb, "Abort forced by user");
4450 
4451 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
4452 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
4453 
4454 	es = sbi->s_es;
4455 
4456 	if (sbi->s_journal) {
4457 		ext4_init_journal_params(sb, sbi->s_journal);
4458 		set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
4459 	}
4460 
4461 	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY)) {
4462 		if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) {
4463 			err = -EROFS;
4464 			goto restore_opts;
4465 		}
4466 
4467 		if (*flags & MS_RDONLY) {
4468 			err = dquot_suspend(sb, -1);
4469 			if (err < 0)
4470 				goto restore_opts;
4471 
4472 			/*
4473 			 * First of all, the unconditional stuff we have to do
4474 			 * to disable replay of the journal when we next remount
4475 			 */
4476 			sb->s_flags |= MS_RDONLY;
4477 
4478 			/*
4479 			 * OK, test if we are remounting a valid rw partition
4480 			 * readonly, and if so set the rdonly flag and then
4481 			 * mark the partition as valid again.
4482 			 */
4483 			if (!(es->s_state & cpu_to_le16(EXT4_VALID_FS)) &&
4484 			    (sbi->s_mount_state & EXT4_VALID_FS))
4485 				es->s_state = cpu_to_le16(sbi->s_mount_state);
4486 
4487 			if (sbi->s_journal)
4488 				ext4_mark_recovery_complete(sb, es);
4489 		} else {
4490 			/* Make sure we can mount this feature set readwrite */
4491 			if (!ext4_feature_set_ok(sb, 0)) {
4492 				err = -EROFS;
4493 				goto restore_opts;
4494 			}
4495 			/*
4496 			 * Make sure the group descriptor checksums
4497 			 * are sane.  If they aren't, refuse to remount r/w.
4498 			 */
4499 			for (g = 0; g < sbi->s_groups_count; g++) {
4500 				struct ext4_group_desc *gdp =
4501 					ext4_get_group_desc(sb, g, NULL);
4502 
4503 				if (!ext4_group_desc_csum_verify(sb, g, gdp)) {
4504 					ext4_msg(sb, KERN_ERR,
4505 	       "ext4_remount: Checksum for group %u failed (%u!=%u)",
4506 		g, le16_to_cpu(ext4_group_desc_csum(sbi, g, gdp)),
4507 					       le16_to_cpu(gdp->bg_checksum));
4508 					err = -EINVAL;
4509 					goto restore_opts;
4510 				}
4511 			}
4512 
4513 			/*
4514 			 * If we have an unprocessed orphan list hanging
4515 			 * around from a previously readonly bdev mount,
4516 			 * require a full umount/remount for now.
4517 			 */
4518 			if (es->s_last_orphan) {
4519 				ext4_msg(sb, KERN_WARNING, "Couldn't "
4520 				       "remount RDWR because of unprocessed "
4521 				       "orphan inode list.  Please "
4522 				       "umount/remount instead");
4523 				err = -EINVAL;
4524 				goto restore_opts;
4525 			}
4526 
4527 			/*
4528 			 * Mounting a RDONLY partition read-write, so reread
4529 			 * and store the current valid flag.  (It may have
4530 			 * been changed by e2fsck since we originally mounted
4531 			 * the partition.)
4532 			 */
4533 			if (sbi->s_journal)
4534 				ext4_clear_journal_err(sb, es);
4535 			sbi->s_mount_state = le16_to_cpu(es->s_state);
4536 			if (!ext4_setup_super(sb, es, 0))
4537 				sb->s_flags &= ~MS_RDONLY;
4538 			if (EXT4_HAS_INCOMPAT_FEATURE(sb,
4539 						     EXT4_FEATURE_INCOMPAT_MMP))
4540 				if (ext4_multi_mount_protect(sb,
4541 						le64_to_cpu(es->s_mmp_block))) {
4542 					err = -EROFS;
4543 					goto restore_opts;
4544 				}
4545 			enable_quota = 1;
4546 		}
4547 	}
4548 
4549 	/*
4550 	 * Reinitialize lazy itable initialization thread based on
4551 	 * current settings
4552 	 */
4553 	if ((sb->s_flags & MS_RDONLY) || !test_opt(sb, INIT_INODE_TABLE))
4554 		ext4_unregister_li_request(sb);
4555 	else {
4556 		ext4_group_t first_not_zeroed;
4557 		first_not_zeroed = ext4_has_uninit_itable(sb);
4558 		ext4_register_li_request(sb, first_not_zeroed);
4559 	}
4560 
4561 	ext4_setup_system_zone(sb);
4562 	if (sbi->s_journal == NULL)
4563 		ext4_commit_super(sb, 1);
4564 
4565 #ifdef CONFIG_QUOTA
4566 	/* Release old quota file names */
4567 	for (i = 0; i < MAXQUOTAS; i++)
4568 		if (old_opts.s_qf_names[i] &&
4569 		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
4570 			kfree(old_opts.s_qf_names[i]);
4571 #endif
4572 	unlock_super(sb);
4573 	if (enable_quota)
4574 		dquot_resume(sb, -1);
4575 
4576 	ext4_msg(sb, KERN_INFO, "re-mounted. Opts: %s", orig_data);
4577 	kfree(orig_data);
4578 	return 0;
4579 
4580 restore_opts:
4581 	sb->s_flags = old_sb_flags;
4582 	sbi->s_mount_opt = old_opts.s_mount_opt;
4583 	sbi->s_mount_opt2 = old_opts.s_mount_opt2;
4584 	sbi->s_resuid = old_opts.s_resuid;
4585 	sbi->s_resgid = old_opts.s_resgid;
4586 	sbi->s_commit_interval = old_opts.s_commit_interval;
4587 	sbi->s_min_batch_time = old_opts.s_min_batch_time;
4588 	sbi->s_max_batch_time = old_opts.s_max_batch_time;
4589 #ifdef CONFIG_QUOTA
4590 	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
4591 	for (i = 0; i < MAXQUOTAS; i++) {
4592 		if (sbi->s_qf_names[i] &&
4593 		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
4594 			kfree(sbi->s_qf_names[i]);
4595 		sbi->s_qf_names[i] = old_opts.s_qf_names[i];
4596 	}
4597 #endif
4598 	unlock_super(sb);
4599 	kfree(orig_data);
4600 	return err;
4601 }
4602 
4603 /*
4604  * Note: calculating the overhead so we can be compatible with
4605  * historical BSD practice is quite difficult in the face of
4606  * clusters/bigalloc.  This is because multiple metadata blocks from
4607  * different block group can end up in the same allocation cluster.
4608  * Calculating the exact overhead in the face of clustered allocation
4609  * requires either O(all block bitmaps) in memory or O(number of block
4610  * groups**2) in time.  We will still calculate the superblock for
4611  * older file systems --- and if we come across with a bigalloc file
4612  * system with zero in s_overhead_clusters the estimate will be close to
4613  * correct especially for very large cluster sizes --- but for newer
4614  * file systems, it's better to calculate this figure once at mkfs
4615  * time, and store it in the superblock.  If the superblock value is
4616  * present (even for non-bigalloc file systems), we will use it.
4617  */
4618 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
4619 {
4620 	struct super_block *sb = dentry->d_sb;
4621 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4622 	struct ext4_super_block *es = sbi->s_es;
4623 	struct ext4_group_desc *gdp;
4624 	u64 fsid;
4625 	s64 bfree;
4626 
4627 	if (test_opt(sb, MINIX_DF)) {
4628 		sbi->s_overhead_last = 0;
4629 	} else if (es->s_overhead_clusters) {
4630 		sbi->s_overhead_last = le32_to_cpu(es->s_overhead_clusters);
4631 	} else if (sbi->s_blocks_last != ext4_blocks_count(es)) {
4632 		ext4_group_t i, ngroups = ext4_get_groups_count(sb);
4633 		ext4_fsblk_t overhead = 0;
4634 
4635 		/*
4636 		 * Compute the overhead (FS structures).  This is constant
4637 		 * for a given filesystem unless the number of block groups
4638 		 * changes so we cache the previous value until it does.
4639 		 */
4640 
4641 		/*
4642 		 * All of the blocks before first_data_block are
4643 		 * overhead
4644 		 */
4645 		overhead = EXT4_B2C(sbi, le32_to_cpu(es->s_first_data_block));
4646 
4647 		/*
4648 		 * Add the overhead found in each block group
4649 		 */
4650 		for (i = 0; i < ngroups; i++) {
4651 			gdp = ext4_get_group_desc(sb, i, NULL);
4652 			overhead += ext4_num_overhead_clusters(sb, i, gdp);
4653 			cond_resched();
4654 		}
4655 		sbi->s_overhead_last = overhead;
4656 		smp_wmb();
4657 		sbi->s_blocks_last = ext4_blocks_count(es);
4658 	}
4659 
4660 	buf->f_type = EXT4_SUPER_MAGIC;
4661 	buf->f_bsize = sb->s_blocksize;
4662 	buf->f_blocks = (ext4_blocks_count(es) -
4663 			 EXT4_C2B(sbi, sbi->s_overhead_last));
4664 	bfree = percpu_counter_sum_positive(&sbi->s_freeclusters_counter) -
4665 		percpu_counter_sum_positive(&sbi->s_dirtyclusters_counter);
4666 	/* prevent underflow in case that few free space is available */
4667 	buf->f_bfree = EXT4_C2B(sbi, max_t(s64, bfree, 0));
4668 	buf->f_bavail = buf->f_bfree - ext4_r_blocks_count(es);
4669 	if (buf->f_bfree < ext4_r_blocks_count(es))
4670 		buf->f_bavail = 0;
4671 	buf->f_files = le32_to_cpu(es->s_inodes_count);
4672 	buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter);
4673 	buf->f_namelen = EXT4_NAME_LEN;
4674 	fsid = le64_to_cpup((void *)es->s_uuid) ^
4675 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
4676 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
4677 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
4678 
4679 	return 0;
4680 }
4681 
4682 /* Helper function for writing quotas on sync - we need to start transaction
4683  * before quota file is locked for write. Otherwise the are possible deadlocks:
4684  * Process 1                         Process 2
4685  * ext4_create()                     quota_sync()
4686  *   jbd2_journal_start()                  write_dquot()
4687  *   dquot_initialize()                         down(dqio_mutex)
4688  *     down(dqio_mutex)                    jbd2_journal_start()
4689  *
4690  */
4691 
4692 #ifdef CONFIG_QUOTA
4693 
4694 static inline struct inode *dquot_to_inode(struct dquot *dquot)
4695 {
4696 	return sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
4697 }
4698 
4699 static int ext4_write_dquot(struct dquot *dquot)
4700 {
4701 	int ret, err;
4702 	handle_t *handle;
4703 	struct inode *inode;
4704 
4705 	inode = dquot_to_inode(dquot);
4706 	handle = ext4_journal_start(inode,
4707 				    EXT4_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
4708 	if (IS_ERR(handle))
4709 		return PTR_ERR(handle);
4710 	ret = dquot_commit(dquot);
4711 	err = ext4_journal_stop(handle);
4712 	if (!ret)
4713 		ret = err;
4714 	return ret;
4715 }
4716 
4717 static int ext4_acquire_dquot(struct dquot *dquot)
4718 {
4719 	int ret, err;
4720 	handle_t *handle;
4721 
4722 	handle = ext4_journal_start(dquot_to_inode(dquot),
4723 				    EXT4_QUOTA_INIT_BLOCKS(dquot->dq_sb));
4724 	if (IS_ERR(handle))
4725 		return PTR_ERR(handle);
4726 	ret = dquot_acquire(dquot);
4727 	err = ext4_journal_stop(handle);
4728 	if (!ret)
4729 		ret = err;
4730 	return ret;
4731 }
4732 
4733 static int ext4_release_dquot(struct dquot *dquot)
4734 {
4735 	int ret, err;
4736 	handle_t *handle;
4737 
4738 	handle = ext4_journal_start(dquot_to_inode(dquot),
4739 				    EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
4740 	if (IS_ERR(handle)) {
4741 		/* Release dquot anyway to avoid endless cycle in dqput() */
4742 		dquot_release(dquot);
4743 		return PTR_ERR(handle);
4744 	}
4745 	ret = dquot_release(dquot);
4746 	err = ext4_journal_stop(handle);
4747 	if (!ret)
4748 		ret = err;
4749 	return ret;
4750 }
4751 
4752 static int ext4_mark_dquot_dirty(struct dquot *dquot)
4753 {
4754 	/* Are we journaling quotas? */
4755 	if (EXT4_SB(dquot->dq_sb)->s_qf_names[USRQUOTA] ||
4756 	    EXT4_SB(dquot->dq_sb)->s_qf_names[GRPQUOTA]) {
4757 		dquot_mark_dquot_dirty(dquot);
4758 		return ext4_write_dquot(dquot);
4759 	} else {
4760 		return dquot_mark_dquot_dirty(dquot);
4761 	}
4762 }
4763 
4764 static int ext4_write_info(struct super_block *sb, int type)
4765 {
4766 	int ret, err;
4767 	handle_t *handle;
4768 
4769 	/* Data block + inode block */
4770 	handle = ext4_journal_start(sb->s_root->d_inode, 2);
4771 	if (IS_ERR(handle))
4772 		return PTR_ERR(handle);
4773 	ret = dquot_commit_info(sb, type);
4774 	err = ext4_journal_stop(handle);
4775 	if (!ret)
4776 		ret = err;
4777 	return ret;
4778 }
4779 
4780 /*
4781  * Turn on quotas during mount time - we need to find
4782  * the quota file and such...
4783  */
4784 static int ext4_quota_on_mount(struct super_block *sb, int type)
4785 {
4786 	return dquot_quota_on_mount(sb, EXT4_SB(sb)->s_qf_names[type],
4787 					EXT4_SB(sb)->s_jquota_fmt, type);
4788 }
4789 
4790 /*
4791  * Standard function to be called on quota_on
4792  */
4793 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
4794 			 struct path *path)
4795 {
4796 	int err;
4797 
4798 	if (!test_opt(sb, QUOTA))
4799 		return -EINVAL;
4800 
4801 	/* Quotafile not on the same filesystem? */
4802 	if (path->dentry->d_sb != sb)
4803 		return -EXDEV;
4804 	/* Journaling quota? */
4805 	if (EXT4_SB(sb)->s_qf_names[type]) {
4806 		/* Quotafile not in fs root? */
4807 		if (path->dentry->d_parent != sb->s_root)
4808 			ext4_msg(sb, KERN_WARNING,
4809 				"Quota file not on filesystem root. "
4810 				"Journaled quota will not work");
4811 	}
4812 
4813 	/*
4814 	 * When we journal data on quota file, we have to flush journal to see
4815 	 * all updates to the file when we bypass pagecache...
4816 	 */
4817 	if (EXT4_SB(sb)->s_journal &&
4818 	    ext4_should_journal_data(path->dentry->d_inode)) {
4819 		/*
4820 		 * We don't need to lock updates but journal_flush() could
4821 		 * otherwise be livelocked...
4822 		 */
4823 		jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
4824 		err = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
4825 		jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
4826 		if (err)
4827 			return err;
4828 	}
4829 
4830 	return dquot_quota_on(sb, type, format_id, path);
4831 }
4832 
4833 static int ext4_quota_off(struct super_block *sb, int type)
4834 {
4835 	struct inode *inode = sb_dqopt(sb)->files[type];
4836 	handle_t *handle;
4837 
4838 	/* Force all delayed allocation blocks to be allocated.
4839 	 * Caller already holds s_umount sem */
4840 	if (test_opt(sb, DELALLOC))
4841 		sync_filesystem(sb);
4842 
4843 	if (!inode)
4844 		goto out;
4845 
4846 	/* Update modification times of quota files when userspace can
4847 	 * start looking at them */
4848 	handle = ext4_journal_start(inode, 1);
4849 	if (IS_ERR(handle))
4850 		goto out;
4851 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
4852 	ext4_mark_inode_dirty(handle, inode);
4853 	ext4_journal_stop(handle);
4854 
4855 out:
4856 	return dquot_quota_off(sb, type);
4857 }
4858 
4859 /* Read data from quotafile - avoid pagecache and such because we cannot afford
4860  * acquiring the locks... As quota files are never truncated and quota code
4861  * itself serializes the operations (and no one else should touch the files)
4862  * we don't have to be afraid of races */
4863 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
4864 			       size_t len, loff_t off)
4865 {
4866 	struct inode *inode = sb_dqopt(sb)->files[type];
4867 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
4868 	int err = 0;
4869 	int offset = off & (sb->s_blocksize - 1);
4870 	int tocopy;
4871 	size_t toread;
4872 	struct buffer_head *bh;
4873 	loff_t i_size = i_size_read(inode);
4874 
4875 	if (off > i_size)
4876 		return 0;
4877 	if (off+len > i_size)
4878 		len = i_size-off;
4879 	toread = len;
4880 	while (toread > 0) {
4881 		tocopy = sb->s_blocksize - offset < toread ?
4882 				sb->s_blocksize - offset : toread;
4883 		bh = ext4_bread(NULL, inode, blk, 0, &err);
4884 		if (err)
4885 			return err;
4886 		if (!bh)	/* A hole? */
4887 			memset(data, 0, tocopy);
4888 		else
4889 			memcpy(data, bh->b_data+offset, tocopy);
4890 		brelse(bh);
4891 		offset = 0;
4892 		toread -= tocopy;
4893 		data += tocopy;
4894 		blk++;
4895 	}
4896 	return len;
4897 }
4898 
4899 /* Write to quotafile (we know the transaction is already started and has
4900  * enough credits) */
4901 static ssize_t ext4_quota_write(struct super_block *sb, int type,
4902 				const char *data, size_t len, loff_t off)
4903 {
4904 	struct inode *inode = sb_dqopt(sb)->files[type];
4905 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
4906 	int err = 0;
4907 	int offset = off & (sb->s_blocksize - 1);
4908 	struct buffer_head *bh;
4909 	handle_t *handle = journal_current_handle();
4910 
4911 	if (EXT4_SB(sb)->s_journal && !handle) {
4912 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
4913 			" cancelled because transaction is not started",
4914 			(unsigned long long)off, (unsigned long long)len);
4915 		return -EIO;
4916 	}
4917 	/*
4918 	 * Since we account only one data block in transaction credits,
4919 	 * then it is impossible to cross a block boundary.
4920 	 */
4921 	if (sb->s_blocksize - offset < len) {
4922 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
4923 			" cancelled because not block aligned",
4924 			(unsigned long long)off, (unsigned long long)len);
4925 		return -EIO;
4926 	}
4927 
4928 	bh = ext4_bread(handle, inode, blk, 1, &err);
4929 	if (!bh)
4930 		goto out;
4931 	err = ext4_journal_get_write_access(handle, bh);
4932 	if (err) {
4933 		brelse(bh);
4934 		goto out;
4935 	}
4936 	lock_buffer(bh);
4937 	memcpy(bh->b_data+offset, data, len);
4938 	flush_dcache_page(bh->b_page);
4939 	unlock_buffer(bh);
4940 	err = ext4_handle_dirty_metadata(handle, NULL, bh);
4941 	brelse(bh);
4942 out:
4943 	if (err)
4944 		return err;
4945 	if (inode->i_size < off + len) {
4946 		i_size_write(inode, off + len);
4947 		EXT4_I(inode)->i_disksize = inode->i_size;
4948 		ext4_mark_inode_dirty(handle, inode);
4949 	}
4950 	return len;
4951 }
4952 
4953 #endif
4954 
4955 static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
4956 		       const char *dev_name, void *data)
4957 {
4958 	return mount_bdev(fs_type, flags, dev_name, data, ext4_fill_super);
4959 }
4960 
4961 #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
4962 static inline void register_as_ext2(void)
4963 {
4964 	int err = register_filesystem(&ext2_fs_type);
4965 	if (err)
4966 		printk(KERN_WARNING
4967 		       "EXT4-fs: Unable to register as ext2 (%d)\n", err);
4968 }
4969 
4970 static inline void unregister_as_ext2(void)
4971 {
4972 	unregister_filesystem(&ext2_fs_type);
4973 }
4974 
4975 static inline int ext2_feature_set_ok(struct super_block *sb)
4976 {
4977 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP))
4978 		return 0;
4979 	if (sb->s_flags & MS_RDONLY)
4980 		return 1;
4981 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))
4982 		return 0;
4983 	return 1;
4984 }
4985 MODULE_ALIAS("ext2");
4986 #else
4987 static inline void register_as_ext2(void) { }
4988 static inline void unregister_as_ext2(void) { }
4989 static inline int ext2_feature_set_ok(struct super_block *sb) { return 0; }
4990 #endif
4991 
4992 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
4993 static inline void register_as_ext3(void)
4994 {
4995 	int err = register_filesystem(&ext3_fs_type);
4996 	if (err)
4997 		printk(KERN_WARNING
4998 		       "EXT4-fs: Unable to register as ext3 (%d)\n", err);
4999 }
5000 
5001 static inline void unregister_as_ext3(void)
5002 {
5003 	unregister_filesystem(&ext3_fs_type);
5004 }
5005 
5006 static inline int ext3_feature_set_ok(struct super_block *sb)
5007 {
5008 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT3_FEATURE_INCOMPAT_SUPP))
5009 		return 0;
5010 	if (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL))
5011 		return 0;
5012 	if (sb->s_flags & MS_RDONLY)
5013 		return 1;
5014 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT3_FEATURE_RO_COMPAT_SUPP))
5015 		return 0;
5016 	return 1;
5017 }
5018 MODULE_ALIAS("ext3");
5019 #else
5020 static inline void register_as_ext3(void) { }
5021 static inline void unregister_as_ext3(void) { }
5022 static inline int ext3_feature_set_ok(struct super_block *sb) { return 0; }
5023 #endif
5024 
5025 static struct file_system_type ext4_fs_type = {
5026 	.owner		= THIS_MODULE,
5027 	.name		= "ext4",
5028 	.mount		= ext4_mount,
5029 	.kill_sb	= kill_block_super,
5030 	.fs_flags	= FS_REQUIRES_DEV,
5031 };
5032 
5033 static int __init ext4_init_feat_adverts(void)
5034 {
5035 	struct ext4_features *ef;
5036 	int ret = -ENOMEM;
5037 
5038 	ef = kzalloc(sizeof(struct ext4_features), GFP_KERNEL);
5039 	if (!ef)
5040 		goto out;
5041 
5042 	ef->f_kobj.kset = ext4_kset;
5043 	init_completion(&ef->f_kobj_unregister);
5044 	ret = kobject_init_and_add(&ef->f_kobj, &ext4_feat_ktype, NULL,
5045 				   "features");
5046 	if (ret) {
5047 		kfree(ef);
5048 		goto out;
5049 	}
5050 
5051 	ext4_feat = ef;
5052 	ret = 0;
5053 out:
5054 	return ret;
5055 }
5056 
5057 static void ext4_exit_feat_adverts(void)
5058 {
5059 	kobject_put(&ext4_feat->f_kobj);
5060 	wait_for_completion(&ext4_feat->f_kobj_unregister);
5061 	kfree(ext4_feat);
5062 }
5063 
5064 /* Shared across all ext4 file systems */
5065 wait_queue_head_t ext4__ioend_wq[EXT4_WQ_HASH_SZ];
5066 struct mutex ext4__aio_mutex[EXT4_WQ_HASH_SZ];
5067 
5068 static int __init ext4_init_fs(void)
5069 {
5070 	int i, err;
5071 
5072 	ext4_li_info = NULL;
5073 	mutex_init(&ext4_li_mtx);
5074 
5075 	ext4_check_flag_values();
5076 
5077 	for (i = 0; i < EXT4_WQ_HASH_SZ; i++) {
5078 		mutex_init(&ext4__aio_mutex[i]);
5079 		init_waitqueue_head(&ext4__ioend_wq[i]);
5080 	}
5081 
5082 	err = ext4_init_pageio();
5083 	if (err)
5084 		return err;
5085 	err = ext4_init_system_zone();
5086 	if (err)
5087 		goto out6;
5088 	ext4_kset = kset_create_and_add("ext4", NULL, fs_kobj);
5089 	if (!ext4_kset)
5090 		goto out5;
5091 	ext4_proc_root = proc_mkdir("fs/ext4", NULL);
5092 
5093 	err = ext4_init_feat_adverts();
5094 	if (err)
5095 		goto out4;
5096 
5097 	err = ext4_init_mballoc();
5098 	if (err)
5099 		goto out3;
5100 
5101 	err = ext4_init_xattr();
5102 	if (err)
5103 		goto out2;
5104 	err = init_inodecache();
5105 	if (err)
5106 		goto out1;
5107 	register_as_ext3();
5108 	register_as_ext2();
5109 	err = register_filesystem(&ext4_fs_type);
5110 	if (err)
5111 		goto out;
5112 
5113 	return 0;
5114 out:
5115 	unregister_as_ext2();
5116 	unregister_as_ext3();
5117 	destroy_inodecache();
5118 out1:
5119 	ext4_exit_xattr();
5120 out2:
5121 	ext4_exit_mballoc();
5122 out3:
5123 	ext4_exit_feat_adverts();
5124 out4:
5125 	if (ext4_proc_root)
5126 		remove_proc_entry("fs/ext4", NULL);
5127 	kset_unregister(ext4_kset);
5128 out5:
5129 	ext4_exit_system_zone();
5130 out6:
5131 	ext4_exit_pageio();
5132 	return err;
5133 }
5134 
5135 static void __exit ext4_exit_fs(void)
5136 {
5137 	ext4_destroy_lazyinit_thread();
5138 	unregister_as_ext2();
5139 	unregister_as_ext3();
5140 	unregister_filesystem(&ext4_fs_type);
5141 	destroy_inodecache();
5142 	ext4_exit_xattr();
5143 	ext4_exit_mballoc();
5144 	ext4_exit_feat_adverts();
5145 	remove_proc_entry("fs/ext4", NULL);
5146 	kset_unregister(ext4_kset);
5147 	ext4_exit_system_zone();
5148 	ext4_exit_pageio();
5149 }
5150 
5151 MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
5152 MODULE_DESCRIPTION("Fourth Extended Filesystem");
5153 MODULE_LICENSE("GPL");
5154 module_init(ext4_init_fs)
5155 module_exit(ext4_exit_fs)
5156