xref: /linux/fs/ext4/super.c (revision 2504075d383fcefd746dac42a0cd1c3bdc006bd1)
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 <asm/uaccess.h>
42 
43 #include <linux/kthread.h>
44 #include <linux/freezer.h>
45 
46 #include "ext4.h"
47 #include "ext4_jbd2.h"
48 #include "xattr.h"
49 #include "acl.h"
50 #include "mballoc.h"
51 
52 #define CREATE_TRACE_POINTS
53 #include <trace/events/ext4.h>
54 
55 static struct proc_dir_entry *ext4_proc_root;
56 static struct kset *ext4_kset;
57 struct ext4_lazy_init *ext4_li_info;
58 struct mutex ext4_li_mtx;
59 struct ext4_features *ext4_feat;
60 
61 static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
62 			     unsigned long journal_devnum);
63 static int ext4_commit_super(struct super_block *sb, int sync);
64 static void ext4_mark_recovery_complete(struct super_block *sb,
65 					struct ext4_super_block *es);
66 static void ext4_clear_journal_err(struct super_block *sb,
67 				   struct ext4_super_block *es);
68 static int ext4_sync_fs(struct super_block *sb, int wait);
69 static const char *ext4_decode_error(struct super_block *sb, int errno,
70 				     char nbuf[16]);
71 static int ext4_remount(struct super_block *sb, int *flags, char *data);
72 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf);
73 static int ext4_unfreeze(struct super_block *sb);
74 static void ext4_write_super(struct super_block *sb);
75 static int ext4_freeze(struct super_block *sb);
76 static int ext4_get_sb(struct file_system_type *fs_type, int flags,
77 		       const char *dev_name, void *data, struct vfsmount *mnt);
78 static void ext4_destroy_lazyinit_thread(void);
79 static void ext4_unregister_li_request(struct super_block *sb);
80 
81 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
82 static struct file_system_type ext3_fs_type = {
83 	.owner		= THIS_MODULE,
84 	.name		= "ext3",
85 	.get_sb		= ext4_get_sb,
86 	.kill_sb	= kill_block_super,
87 	.fs_flags	= FS_REQUIRES_DEV,
88 };
89 #define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type)
90 #else
91 #define IS_EXT3_SB(sb) (0)
92 #endif
93 
94 ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
95 			       struct ext4_group_desc *bg)
96 {
97 	return le32_to_cpu(bg->bg_block_bitmap_lo) |
98 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
99 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_block_bitmap_hi) << 32 : 0);
100 }
101 
102 ext4_fsblk_t ext4_inode_bitmap(struct super_block *sb,
103 			       struct ext4_group_desc *bg)
104 {
105 	return le32_to_cpu(bg->bg_inode_bitmap_lo) |
106 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
107 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_bitmap_hi) << 32 : 0);
108 }
109 
110 ext4_fsblk_t ext4_inode_table(struct super_block *sb,
111 			      struct ext4_group_desc *bg)
112 {
113 	return le32_to_cpu(bg->bg_inode_table_lo) |
114 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
115 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_table_hi) << 32 : 0);
116 }
117 
118 __u32 ext4_free_blks_count(struct super_block *sb,
119 			      struct ext4_group_desc *bg)
120 {
121 	return le16_to_cpu(bg->bg_free_blocks_count_lo) |
122 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
123 		 (__u32)le16_to_cpu(bg->bg_free_blocks_count_hi) << 16 : 0);
124 }
125 
126 __u32 ext4_free_inodes_count(struct super_block *sb,
127 			      struct ext4_group_desc *bg)
128 {
129 	return le16_to_cpu(bg->bg_free_inodes_count_lo) |
130 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
131 		 (__u32)le16_to_cpu(bg->bg_free_inodes_count_hi) << 16 : 0);
132 }
133 
134 __u32 ext4_used_dirs_count(struct super_block *sb,
135 			      struct ext4_group_desc *bg)
136 {
137 	return le16_to_cpu(bg->bg_used_dirs_count_lo) |
138 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
139 		 (__u32)le16_to_cpu(bg->bg_used_dirs_count_hi) << 16 : 0);
140 }
141 
142 __u32 ext4_itable_unused_count(struct super_block *sb,
143 			      struct ext4_group_desc *bg)
144 {
145 	return le16_to_cpu(bg->bg_itable_unused_lo) |
146 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
147 		 (__u32)le16_to_cpu(bg->bg_itable_unused_hi) << 16 : 0);
148 }
149 
150 void ext4_block_bitmap_set(struct super_block *sb,
151 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
152 {
153 	bg->bg_block_bitmap_lo = cpu_to_le32((u32)blk);
154 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
155 		bg->bg_block_bitmap_hi = cpu_to_le32(blk >> 32);
156 }
157 
158 void ext4_inode_bitmap_set(struct super_block *sb,
159 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
160 {
161 	bg->bg_inode_bitmap_lo  = cpu_to_le32((u32)blk);
162 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
163 		bg->bg_inode_bitmap_hi = cpu_to_le32(blk >> 32);
164 }
165 
166 void ext4_inode_table_set(struct super_block *sb,
167 			  struct ext4_group_desc *bg, ext4_fsblk_t blk)
168 {
169 	bg->bg_inode_table_lo = cpu_to_le32((u32)blk);
170 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
171 		bg->bg_inode_table_hi = cpu_to_le32(blk >> 32);
172 }
173 
174 void ext4_free_blks_set(struct super_block *sb,
175 			  struct ext4_group_desc *bg, __u32 count)
176 {
177 	bg->bg_free_blocks_count_lo = cpu_to_le16((__u16)count);
178 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
179 		bg->bg_free_blocks_count_hi = cpu_to_le16(count >> 16);
180 }
181 
182 void ext4_free_inodes_set(struct super_block *sb,
183 			  struct ext4_group_desc *bg, __u32 count)
184 {
185 	bg->bg_free_inodes_count_lo = cpu_to_le16((__u16)count);
186 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
187 		bg->bg_free_inodes_count_hi = cpu_to_le16(count >> 16);
188 }
189 
190 void ext4_used_dirs_set(struct super_block *sb,
191 			  struct ext4_group_desc *bg, __u32 count)
192 {
193 	bg->bg_used_dirs_count_lo = cpu_to_le16((__u16)count);
194 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
195 		bg->bg_used_dirs_count_hi = cpu_to_le16(count >> 16);
196 }
197 
198 void ext4_itable_unused_set(struct super_block *sb,
199 			  struct ext4_group_desc *bg, __u32 count)
200 {
201 	bg->bg_itable_unused_lo = cpu_to_le16((__u16)count);
202 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
203 		bg->bg_itable_unused_hi = cpu_to_le16(count >> 16);
204 }
205 
206 
207 /* Just increment the non-pointer handle value */
208 static handle_t *ext4_get_nojournal(void)
209 {
210 	handle_t *handle = current->journal_info;
211 	unsigned long ref_cnt = (unsigned long)handle;
212 
213 	BUG_ON(ref_cnt >= EXT4_NOJOURNAL_MAX_REF_COUNT);
214 
215 	ref_cnt++;
216 	handle = (handle_t *)ref_cnt;
217 
218 	current->journal_info = handle;
219 	return handle;
220 }
221 
222 
223 /* Decrement the non-pointer handle value */
224 static void ext4_put_nojournal(handle_t *handle)
225 {
226 	unsigned long ref_cnt = (unsigned long)handle;
227 
228 	BUG_ON(ref_cnt == 0);
229 
230 	ref_cnt--;
231 	handle = (handle_t *)ref_cnt;
232 
233 	current->journal_info = handle;
234 }
235 
236 /*
237  * Wrappers for jbd2_journal_start/end.
238  *
239  * The only special thing we need to do here is to make sure that all
240  * journal_end calls result in the superblock being marked dirty, so
241  * that sync() will call the filesystem's write_super callback if
242  * appropriate.
243  */
244 handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
245 {
246 	journal_t *journal;
247 
248 	if (sb->s_flags & MS_RDONLY)
249 		return ERR_PTR(-EROFS);
250 
251 	vfs_check_frozen(sb, SB_FREEZE_TRANS);
252 	/* Special case here: if the journal has aborted behind our
253 	 * backs (eg. EIO in the commit thread), then we still need to
254 	 * take the FS itself readonly cleanly. */
255 	journal = EXT4_SB(sb)->s_journal;
256 	if (journal) {
257 		if (is_journal_aborted(journal)) {
258 			ext4_abort(sb, "Detected aborted journal");
259 			return ERR_PTR(-EROFS);
260 		}
261 		return jbd2_journal_start(journal, nblocks);
262 	}
263 	return ext4_get_nojournal();
264 }
265 
266 /*
267  * The only special thing we need to do here is to make sure that all
268  * jbd2_journal_stop calls result in the superblock being marked dirty, so
269  * that sync() will call the filesystem's write_super callback if
270  * appropriate.
271  */
272 int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle)
273 {
274 	struct super_block *sb;
275 	int err;
276 	int rc;
277 
278 	if (!ext4_handle_valid(handle)) {
279 		ext4_put_nojournal(handle);
280 		return 0;
281 	}
282 	sb = handle->h_transaction->t_journal->j_private;
283 	err = handle->h_err;
284 	rc = jbd2_journal_stop(handle);
285 
286 	if (!err)
287 		err = rc;
288 	if (err)
289 		__ext4_std_error(sb, where, line, err);
290 	return err;
291 }
292 
293 void ext4_journal_abort_handle(const char *caller, unsigned int line,
294 			       const char *err_fn, struct buffer_head *bh,
295 			       handle_t *handle, int err)
296 {
297 	char nbuf[16];
298 	const char *errstr = ext4_decode_error(NULL, err, nbuf);
299 
300 	BUG_ON(!ext4_handle_valid(handle));
301 
302 	if (bh)
303 		BUFFER_TRACE(bh, "abort");
304 
305 	if (!handle->h_err)
306 		handle->h_err = err;
307 
308 	if (is_handle_aborted(handle))
309 		return;
310 
311 	printk(KERN_ERR "%s:%d: aborting transaction: %s in %s\n",
312 	       caller, line, errstr, err_fn);
313 
314 	jbd2_journal_abort_handle(handle);
315 }
316 
317 static void __save_error_info(struct super_block *sb, const char *func,
318 			    unsigned int line)
319 {
320 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
321 
322 	EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
323 	es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
324 	es->s_last_error_time = cpu_to_le32(get_seconds());
325 	strncpy(es->s_last_error_func, func, sizeof(es->s_last_error_func));
326 	es->s_last_error_line = cpu_to_le32(line);
327 	if (!es->s_first_error_time) {
328 		es->s_first_error_time = es->s_last_error_time;
329 		strncpy(es->s_first_error_func, func,
330 			sizeof(es->s_first_error_func));
331 		es->s_first_error_line = cpu_to_le32(line);
332 		es->s_first_error_ino = es->s_last_error_ino;
333 		es->s_first_error_block = es->s_last_error_block;
334 	}
335 	/*
336 	 * Start the daily error reporting function if it hasn't been
337 	 * started already
338 	 */
339 	if (!es->s_error_count)
340 		mod_timer(&EXT4_SB(sb)->s_err_report, jiffies + 24*60*60*HZ);
341 	es->s_error_count = cpu_to_le32(le32_to_cpu(es->s_error_count) + 1);
342 }
343 
344 static void save_error_info(struct super_block *sb, const char *func,
345 			    unsigned int line)
346 {
347 	__save_error_info(sb, func, line);
348 	ext4_commit_super(sb, 1);
349 }
350 
351 
352 /* Deal with the reporting of failure conditions on a filesystem such as
353  * inconsistencies detected or read IO failures.
354  *
355  * On ext2, we can store the error state of the filesystem in the
356  * superblock.  That is not possible on ext4, because we may have other
357  * write ordering constraints on the superblock which prevent us from
358  * writing it out straight away; and given that the journal is about to
359  * be aborted, we can't rely on the current, or future, transactions to
360  * write out the superblock safely.
361  *
362  * We'll just use the jbd2_journal_abort() error code to record an error in
363  * the journal instead.  On recovery, the journal will complain about
364  * that error until we've noted it down and cleared it.
365  */
366 
367 static void ext4_handle_error(struct super_block *sb)
368 {
369 	if (sb->s_flags & MS_RDONLY)
370 		return;
371 
372 	if (!test_opt(sb, ERRORS_CONT)) {
373 		journal_t *journal = EXT4_SB(sb)->s_journal;
374 
375 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
376 		if (journal)
377 			jbd2_journal_abort(journal, -EIO);
378 	}
379 	if (test_opt(sb, ERRORS_RO)) {
380 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
381 		sb->s_flags |= MS_RDONLY;
382 	}
383 	if (test_opt(sb, ERRORS_PANIC))
384 		panic("EXT4-fs (device %s): panic forced after error\n",
385 			sb->s_id);
386 }
387 
388 void __ext4_error(struct super_block *sb, const char *function,
389 		  unsigned int line, const char *fmt, ...)
390 {
391 	va_list args;
392 
393 	va_start(args, fmt);
394 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: comm %s: ",
395 	       sb->s_id, function, line, current->comm);
396 	vprintk(fmt, args);
397 	printk("\n");
398 	va_end(args);
399 
400 	ext4_handle_error(sb);
401 }
402 
403 void ext4_error_inode(struct inode *inode, const char *function,
404 		      unsigned int line, ext4_fsblk_t block,
405 		      const char *fmt, ...)
406 {
407 	va_list args;
408 	struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
409 
410 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
411 	es->s_last_error_block = cpu_to_le64(block);
412 	save_error_info(inode->i_sb, function, line);
413 	va_start(args, fmt);
414 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: inode #%lu: ",
415 	       inode->i_sb->s_id, function, line, inode->i_ino);
416 	if (block)
417 		printk("block %llu: ", block);
418 	printk("comm %s: ", current->comm);
419 	vprintk(fmt, args);
420 	printk("\n");
421 	va_end(args);
422 
423 	ext4_handle_error(inode->i_sb);
424 }
425 
426 void ext4_error_file(struct file *file, const char *function,
427 		     unsigned int line, const char *fmt, ...)
428 {
429 	va_list args;
430 	struct ext4_super_block *es;
431 	struct inode *inode = file->f_dentry->d_inode;
432 	char pathname[80], *path;
433 
434 	es = EXT4_SB(inode->i_sb)->s_es;
435 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
436 	save_error_info(inode->i_sb, function, line);
437 	va_start(args, fmt);
438 	path = d_path(&(file->f_path), pathname, sizeof(pathname));
439 	if (!path)
440 		path = "(unknown)";
441 	printk(KERN_CRIT
442 	       "EXT4-fs error (device %s): %s:%d: inode #%lu "
443 	       "(comm %s path %s): ",
444 	       inode->i_sb->s_id, function, line, inode->i_ino,
445 	       current->comm, path);
446 	vprintk(fmt, args);
447 	printk("\n");
448 	va_end(args);
449 
450 	ext4_handle_error(inode->i_sb);
451 }
452 
453 static const char *ext4_decode_error(struct super_block *sb, int errno,
454 				     char nbuf[16])
455 {
456 	char *errstr = NULL;
457 
458 	switch (errno) {
459 	case -EIO:
460 		errstr = "IO failure";
461 		break;
462 	case -ENOMEM:
463 		errstr = "Out of memory";
464 		break;
465 	case -EROFS:
466 		if (!sb || (EXT4_SB(sb)->s_journal &&
467 			    EXT4_SB(sb)->s_journal->j_flags & JBD2_ABORT))
468 			errstr = "Journal has aborted";
469 		else
470 			errstr = "Readonly filesystem";
471 		break;
472 	default:
473 		/* If the caller passed in an extra buffer for unknown
474 		 * errors, textualise them now.  Else we just return
475 		 * NULL. */
476 		if (nbuf) {
477 			/* Check for truncated error codes... */
478 			if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
479 				errstr = nbuf;
480 		}
481 		break;
482 	}
483 
484 	return errstr;
485 }
486 
487 /* __ext4_std_error decodes expected errors from journaling functions
488  * automatically and invokes the appropriate error response.  */
489 
490 void __ext4_std_error(struct super_block *sb, const char *function,
491 		      unsigned int line, int errno)
492 {
493 	char nbuf[16];
494 	const char *errstr;
495 
496 	/* Special case: if the error is EROFS, and we're not already
497 	 * inside a transaction, then there's really no point in logging
498 	 * an error. */
499 	if (errno == -EROFS && journal_current_handle() == NULL &&
500 	    (sb->s_flags & MS_RDONLY))
501 		return;
502 
503 	errstr = ext4_decode_error(sb, errno, nbuf);
504 	printk(KERN_CRIT "EXT4-fs error (device %s) in %s:%d: %s\n",
505 	       sb->s_id, function, line, errstr);
506 	save_error_info(sb, function, line);
507 
508 	ext4_handle_error(sb);
509 }
510 
511 /*
512  * ext4_abort is a much stronger failure handler than ext4_error.  The
513  * abort function may be used to deal with unrecoverable failures such
514  * as journal IO errors or ENOMEM at a critical moment in log management.
515  *
516  * We unconditionally force the filesystem into an ABORT|READONLY state,
517  * unless the error response on the fs has been set to panic in which
518  * case we take the easy way out and panic immediately.
519  */
520 
521 void __ext4_abort(struct super_block *sb, const char *function,
522 		unsigned int line, const char *fmt, ...)
523 {
524 	va_list args;
525 
526 	save_error_info(sb, function, line);
527 	va_start(args, fmt);
528 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: ", sb->s_id,
529 	       function, line);
530 	vprintk(fmt, args);
531 	printk("\n");
532 	va_end(args);
533 
534 	if ((sb->s_flags & MS_RDONLY) == 0) {
535 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
536 		sb->s_flags |= MS_RDONLY;
537 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
538 		if (EXT4_SB(sb)->s_journal)
539 			jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
540 		save_error_info(sb, function, line);
541 	}
542 	if (test_opt(sb, ERRORS_PANIC))
543 		panic("EXT4-fs panic from previous error\n");
544 }
545 
546 void ext4_msg (struct super_block * sb, const char *prefix,
547 		   const char *fmt, ...)
548 {
549 	va_list args;
550 
551 	va_start(args, fmt);
552 	printk("%sEXT4-fs (%s): ", prefix, sb->s_id);
553 	vprintk(fmt, args);
554 	printk("\n");
555 	va_end(args);
556 }
557 
558 void __ext4_warning(struct super_block *sb, const char *function,
559 		    unsigned int line, const char *fmt, ...)
560 {
561 	va_list args;
562 
563 	va_start(args, fmt);
564 	printk(KERN_WARNING "EXT4-fs warning (device %s): %s:%d: ",
565 	       sb->s_id, function, line);
566 	vprintk(fmt, args);
567 	printk("\n");
568 	va_end(args);
569 }
570 
571 void __ext4_grp_locked_error(const char *function, unsigned int line,
572 			     struct super_block *sb, ext4_group_t grp,
573 			     unsigned long ino, ext4_fsblk_t block,
574 			     const char *fmt, ...)
575 __releases(bitlock)
576 __acquires(bitlock)
577 {
578 	va_list args;
579 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
580 
581 	es->s_last_error_ino = cpu_to_le32(ino);
582 	es->s_last_error_block = cpu_to_le64(block);
583 	__save_error_info(sb, function, line);
584 	va_start(args, fmt);
585 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: group %u",
586 	       sb->s_id, function, line, grp);
587 	if (ino)
588 		printk("inode %lu: ", ino);
589 	if (block)
590 		printk("block %llu:", (unsigned long long) block);
591 	vprintk(fmt, args);
592 	printk("\n");
593 	va_end(args);
594 
595 	if (test_opt(sb, ERRORS_CONT)) {
596 		ext4_commit_super(sb, 0);
597 		return;
598 	}
599 
600 	ext4_unlock_group(sb, grp);
601 	ext4_handle_error(sb);
602 	/*
603 	 * We only get here in the ERRORS_RO case; relocking the group
604 	 * may be dangerous, but nothing bad will happen since the
605 	 * filesystem will have already been marked read/only and the
606 	 * journal has been aborted.  We return 1 as a hint to callers
607 	 * who might what to use the return value from
608 	 * ext4_grp_locked_error() to distinguish beween the
609 	 * ERRORS_CONT and ERRORS_RO case, and perhaps return more
610 	 * aggressively from the ext4 function in question, with a
611 	 * more appropriate error code.
612 	 */
613 	ext4_lock_group(sb, grp);
614 	return;
615 }
616 
617 void ext4_update_dynamic_rev(struct super_block *sb)
618 {
619 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
620 
621 	if (le32_to_cpu(es->s_rev_level) > EXT4_GOOD_OLD_REV)
622 		return;
623 
624 	ext4_warning(sb,
625 		     "updating to rev %d because of new feature flag, "
626 		     "running e2fsck is recommended",
627 		     EXT4_DYNAMIC_REV);
628 
629 	es->s_first_ino = cpu_to_le32(EXT4_GOOD_OLD_FIRST_INO);
630 	es->s_inode_size = cpu_to_le16(EXT4_GOOD_OLD_INODE_SIZE);
631 	es->s_rev_level = cpu_to_le32(EXT4_DYNAMIC_REV);
632 	/* leave es->s_feature_*compat flags alone */
633 	/* es->s_uuid will be set by e2fsck if empty */
634 
635 	/*
636 	 * The rest of the superblock fields should be zero, and if not it
637 	 * means they are likely already in use, so leave them alone.  We
638 	 * can leave it up to e2fsck to clean up any inconsistencies there.
639 	 */
640 }
641 
642 /*
643  * Open the external journal device
644  */
645 static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb)
646 {
647 	struct block_device *bdev;
648 	char b[BDEVNAME_SIZE];
649 
650 	bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
651 	if (IS_ERR(bdev))
652 		goto fail;
653 	return bdev;
654 
655 fail:
656 	ext4_msg(sb, KERN_ERR, "failed to open journal device %s: %ld",
657 			__bdevname(dev, b), PTR_ERR(bdev));
658 	return NULL;
659 }
660 
661 /*
662  * Release the journal device
663  */
664 static int ext4_blkdev_put(struct block_device *bdev)
665 {
666 	bd_release(bdev);
667 	return blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
668 }
669 
670 static int ext4_blkdev_remove(struct ext4_sb_info *sbi)
671 {
672 	struct block_device *bdev;
673 	int ret = -ENODEV;
674 
675 	bdev = sbi->journal_bdev;
676 	if (bdev) {
677 		ret = ext4_blkdev_put(bdev);
678 		sbi->journal_bdev = NULL;
679 	}
680 	return ret;
681 }
682 
683 static inline struct inode *orphan_list_entry(struct list_head *l)
684 {
685 	return &list_entry(l, struct ext4_inode_info, i_orphan)->vfs_inode;
686 }
687 
688 static void dump_orphan_list(struct super_block *sb, struct ext4_sb_info *sbi)
689 {
690 	struct list_head *l;
691 
692 	ext4_msg(sb, KERN_ERR, "sb orphan head is %d",
693 		 le32_to_cpu(sbi->s_es->s_last_orphan));
694 
695 	printk(KERN_ERR "sb_info orphan list:\n");
696 	list_for_each(l, &sbi->s_orphan) {
697 		struct inode *inode = orphan_list_entry(l);
698 		printk(KERN_ERR "  "
699 		       "inode %s:%lu at %p: mode %o, nlink %d, next %d\n",
700 		       inode->i_sb->s_id, inode->i_ino, inode,
701 		       inode->i_mode, inode->i_nlink,
702 		       NEXT_ORPHAN(inode));
703 	}
704 }
705 
706 static void ext4_put_super(struct super_block *sb)
707 {
708 	struct ext4_sb_info *sbi = EXT4_SB(sb);
709 	struct ext4_super_block *es = sbi->s_es;
710 	int i, err;
711 
712 	ext4_unregister_li_request(sb);
713 	dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
714 
715 	flush_workqueue(sbi->dio_unwritten_wq);
716 	destroy_workqueue(sbi->dio_unwritten_wq);
717 
718 	lock_super(sb);
719 	if (sb->s_dirt)
720 		ext4_commit_super(sb, 1);
721 
722 	if (sbi->s_journal) {
723 		err = jbd2_journal_destroy(sbi->s_journal);
724 		sbi->s_journal = NULL;
725 		if (err < 0)
726 			ext4_abort(sb, "Couldn't clean up the journal");
727 	}
728 
729 	del_timer(&sbi->s_err_report);
730 	ext4_release_system_zone(sb);
731 	ext4_mb_release(sb);
732 	ext4_ext_release(sb);
733 	ext4_xattr_put_super(sb);
734 
735 	if (!(sb->s_flags & MS_RDONLY)) {
736 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
737 		es->s_state = cpu_to_le16(sbi->s_mount_state);
738 		ext4_commit_super(sb, 1);
739 	}
740 	if (sbi->s_proc) {
741 		remove_proc_entry(sb->s_id, ext4_proc_root);
742 	}
743 	kobject_del(&sbi->s_kobj);
744 
745 	for (i = 0; i < sbi->s_gdb_count; i++)
746 		brelse(sbi->s_group_desc[i]);
747 	kfree(sbi->s_group_desc);
748 	if (is_vmalloc_addr(sbi->s_flex_groups))
749 		vfree(sbi->s_flex_groups);
750 	else
751 		kfree(sbi->s_flex_groups);
752 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
753 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
754 	percpu_counter_destroy(&sbi->s_dirs_counter);
755 	percpu_counter_destroy(&sbi->s_dirtyblocks_counter);
756 	brelse(sbi->s_sbh);
757 #ifdef CONFIG_QUOTA
758 	for (i = 0; i < MAXQUOTAS; i++)
759 		kfree(sbi->s_qf_names[i]);
760 #endif
761 
762 	/* Debugging code just in case the in-memory inode orphan list
763 	 * isn't empty.  The on-disk one can be non-empty if we've
764 	 * detected an error and taken the fs readonly, but the
765 	 * in-memory list had better be clean by this point. */
766 	if (!list_empty(&sbi->s_orphan))
767 		dump_orphan_list(sb, sbi);
768 	J_ASSERT(list_empty(&sbi->s_orphan));
769 
770 	invalidate_bdev(sb->s_bdev);
771 	if (sbi->journal_bdev && sbi->journal_bdev != sb->s_bdev) {
772 		/*
773 		 * Invalidate the journal device's buffers.  We don't want them
774 		 * floating about in memory - the physical journal device may
775 		 * hotswapped, and it breaks the `ro-after' testing code.
776 		 */
777 		sync_blockdev(sbi->journal_bdev);
778 		invalidate_bdev(sbi->journal_bdev);
779 		ext4_blkdev_remove(sbi);
780 	}
781 	sb->s_fs_info = NULL;
782 	/*
783 	 * Now that we are completely done shutting down the
784 	 * superblock, we need to actually destroy the kobject.
785 	 */
786 	unlock_super(sb);
787 	kobject_put(&sbi->s_kobj);
788 	wait_for_completion(&sbi->s_kobj_unregister);
789 	kfree(sbi->s_blockgroup_lock);
790 	kfree(sbi);
791 }
792 
793 static struct kmem_cache *ext4_inode_cachep;
794 
795 /*
796  * Called inside transaction, so use GFP_NOFS
797  */
798 static struct inode *ext4_alloc_inode(struct super_block *sb)
799 {
800 	struct ext4_inode_info *ei;
801 
802 	ei = kmem_cache_alloc(ext4_inode_cachep, GFP_NOFS);
803 	if (!ei)
804 		return NULL;
805 
806 	ei->vfs_inode.i_version = 1;
807 	ei->vfs_inode.i_data.writeback_index = 0;
808 	memset(&ei->i_cached_extent, 0, sizeof(struct ext4_ext_cache));
809 	INIT_LIST_HEAD(&ei->i_prealloc_list);
810 	spin_lock_init(&ei->i_prealloc_lock);
811 	/*
812 	 * Note:  We can be called before EXT4_SB(sb)->s_journal is set,
813 	 * therefore it can be null here.  Don't check it, just initialize
814 	 * jinode.
815 	 */
816 	jbd2_journal_init_jbd_inode(&ei->jinode, &ei->vfs_inode);
817 	ei->i_reserved_data_blocks = 0;
818 	ei->i_reserved_meta_blocks = 0;
819 	ei->i_allocated_meta_blocks = 0;
820 	ei->i_da_metadata_calc_len = 0;
821 	ei->i_delalloc_reserved_flag = 0;
822 	spin_lock_init(&(ei->i_block_reservation_lock));
823 #ifdef CONFIG_QUOTA
824 	ei->i_reserved_quota = 0;
825 #endif
826 	INIT_LIST_HEAD(&ei->i_completed_io_list);
827 	spin_lock_init(&ei->i_completed_io_lock);
828 	ei->cur_aio_dio = NULL;
829 	ei->i_sync_tid = 0;
830 	ei->i_datasync_tid = 0;
831 
832 	return &ei->vfs_inode;
833 }
834 
835 static void ext4_destroy_inode(struct inode *inode)
836 {
837 	if (!list_empty(&(EXT4_I(inode)->i_orphan))) {
838 		ext4_msg(inode->i_sb, KERN_ERR,
839 			 "Inode %lu (%p): orphan list check failed!",
840 			 inode->i_ino, EXT4_I(inode));
841 		print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 16, 4,
842 				EXT4_I(inode), sizeof(struct ext4_inode_info),
843 				true);
844 		dump_stack();
845 	}
846 	kmem_cache_free(ext4_inode_cachep, EXT4_I(inode));
847 }
848 
849 static void init_once(void *foo)
850 {
851 	struct ext4_inode_info *ei = (struct ext4_inode_info *) foo;
852 
853 	INIT_LIST_HEAD(&ei->i_orphan);
854 #ifdef CONFIG_EXT4_FS_XATTR
855 	init_rwsem(&ei->xattr_sem);
856 #endif
857 	init_rwsem(&ei->i_data_sem);
858 	inode_init_once(&ei->vfs_inode);
859 }
860 
861 static int init_inodecache(void)
862 {
863 	ext4_inode_cachep = kmem_cache_create("ext4_inode_cache",
864 					     sizeof(struct ext4_inode_info),
865 					     0, (SLAB_RECLAIM_ACCOUNT|
866 						SLAB_MEM_SPREAD),
867 					     init_once);
868 	if (ext4_inode_cachep == NULL)
869 		return -ENOMEM;
870 	return 0;
871 }
872 
873 static void destroy_inodecache(void)
874 {
875 	kmem_cache_destroy(ext4_inode_cachep);
876 }
877 
878 void ext4_clear_inode(struct inode *inode)
879 {
880 	invalidate_inode_buffers(inode);
881 	end_writeback(inode);
882 	dquot_drop(inode);
883 	ext4_discard_preallocations(inode);
884 	if (EXT4_JOURNAL(inode))
885 		jbd2_journal_release_jbd_inode(EXT4_SB(inode->i_sb)->s_journal,
886 				       &EXT4_I(inode)->jinode);
887 }
888 
889 static inline void ext4_show_quota_options(struct seq_file *seq,
890 					   struct super_block *sb)
891 {
892 #if defined(CONFIG_QUOTA)
893 	struct ext4_sb_info *sbi = EXT4_SB(sb);
894 
895 	if (sbi->s_jquota_fmt) {
896 		char *fmtname = "";
897 
898 		switch (sbi->s_jquota_fmt) {
899 		case QFMT_VFS_OLD:
900 			fmtname = "vfsold";
901 			break;
902 		case QFMT_VFS_V0:
903 			fmtname = "vfsv0";
904 			break;
905 		case QFMT_VFS_V1:
906 			fmtname = "vfsv1";
907 			break;
908 		}
909 		seq_printf(seq, ",jqfmt=%s", fmtname);
910 	}
911 
912 	if (sbi->s_qf_names[USRQUOTA])
913 		seq_printf(seq, ",usrjquota=%s", sbi->s_qf_names[USRQUOTA]);
914 
915 	if (sbi->s_qf_names[GRPQUOTA])
916 		seq_printf(seq, ",grpjquota=%s", sbi->s_qf_names[GRPQUOTA]);
917 
918 	if (test_opt(sb, USRQUOTA))
919 		seq_puts(seq, ",usrquota");
920 
921 	if (test_opt(sb, GRPQUOTA))
922 		seq_puts(seq, ",grpquota");
923 #endif
924 }
925 
926 /*
927  * Show an option if
928  *  - it's set to a non-default value OR
929  *  - if the per-sb default is different from the global default
930  */
931 static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs)
932 {
933 	int def_errors;
934 	unsigned long def_mount_opts;
935 	struct super_block *sb = vfs->mnt_sb;
936 	struct ext4_sb_info *sbi = EXT4_SB(sb);
937 	struct ext4_super_block *es = sbi->s_es;
938 
939 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
940 	def_errors     = le16_to_cpu(es->s_errors);
941 
942 	if (sbi->s_sb_block != 1)
943 		seq_printf(seq, ",sb=%llu", sbi->s_sb_block);
944 	if (test_opt(sb, MINIX_DF))
945 		seq_puts(seq, ",minixdf");
946 	if (test_opt(sb, GRPID) && !(def_mount_opts & EXT4_DEFM_BSDGROUPS))
947 		seq_puts(seq, ",grpid");
948 	if (!test_opt(sb, GRPID) && (def_mount_opts & EXT4_DEFM_BSDGROUPS))
949 		seq_puts(seq, ",nogrpid");
950 	if (sbi->s_resuid != EXT4_DEF_RESUID ||
951 	    le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID) {
952 		seq_printf(seq, ",resuid=%u", sbi->s_resuid);
953 	}
954 	if (sbi->s_resgid != EXT4_DEF_RESGID ||
955 	    le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID) {
956 		seq_printf(seq, ",resgid=%u", sbi->s_resgid);
957 	}
958 	if (test_opt(sb, ERRORS_RO)) {
959 		if (def_errors == EXT4_ERRORS_PANIC ||
960 		    def_errors == EXT4_ERRORS_CONTINUE) {
961 			seq_puts(seq, ",errors=remount-ro");
962 		}
963 	}
964 	if (test_opt(sb, ERRORS_CONT) && def_errors != EXT4_ERRORS_CONTINUE)
965 		seq_puts(seq, ",errors=continue");
966 	if (test_opt(sb, ERRORS_PANIC) && def_errors != EXT4_ERRORS_PANIC)
967 		seq_puts(seq, ",errors=panic");
968 	if (test_opt(sb, NO_UID32) && !(def_mount_opts & EXT4_DEFM_UID16))
969 		seq_puts(seq, ",nouid32");
970 	if (test_opt(sb, DEBUG) && !(def_mount_opts & EXT4_DEFM_DEBUG))
971 		seq_puts(seq, ",debug");
972 	if (test_opt(sb, OLDALLOC))
973 		seq_puts(seq, ",oldalloc");
974 #ifdef CONFIG_EXT4_FS_XATTR
975 	if (test_opt(sb, XATTR_USER) &&
976 		!(def_mount_opts & EXT4_DEFM_XATTR_USER))
977 		seq_puts(seq, ",user_xattr");
978 	if (!test_opt(sb, XATTR_USER) &&
979 	    (def_mount_opts & EXT4_DEFM_XATTR_USER)) {
980 		seq_puts(seq, ",nouser_xattr");
981 	}
982 #endif
983 #ifdef CONFIG_EXT4_FS_POSIX_ACL
984 	if (test_opt(sb, POSIX_ACL) && !(def_mount_opts & EXT4_DEFM_ACL))
985 		seq_puts(seq, ",acl");
986 	if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT4_DEFM_ACL))
987 		seq_puts(seq, ",noacl");
988 #endif
989 	if (sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ) {
990 		seq_printf(seq, ",commit=%u",
991 			   (unsigned) (sbi->s_commit_interval / HZ));
992 	}
993 	if (sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME) {
994 		seq_printf(seq, ",min_batch_time=%u",
995 			   (unsigned) sbi->s_min_batch_time);
996 	}
997 	if (sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME) {
998 		seq_printf(seq, ",max_batch_time=%u",
999 			   (unsigned) sbi->s_min_batch_time);
1000 	}
1001 
1002 	/*
1003 	 * We're changing the default of barrier mount option, so
1004 	 * let's always display its mount state so it's clear what its
1005 	 * status is.
1006 	 */
1007 	seq_puts(seq, ",barrier=");
1008 	seq_puts(seq, test_opt(sb, BARRIER) ? "1" : "0");
1009 	if (test_opt(sb, JOURNAL_ASYNC_COMMIT))
1010 		seq_puts(seq, ",journal_async_commit");
1011 	else if (test_opt(sb, JOURNAL_CHECKSUM))
1012 		seq_puts(seq, ",journal_checksum");
1013 	if (test_opt(sb, I_VERSION))
1014 		seq_puts(seq, ",i_version");
1015 	if (!test_opt(sb, DELALLOC) &&
1016 	    !(def_mount_opts & EXT4_DEFM_NODELALLOC))
1017 		seq_puts(seq, ",nodelalloc");
1018 
1019 	if (sbi->s_stripe)
1020 		seq_printf(seq, ",stripe=%lu", sbi->s_stripe);
1021 	/*
1022 	 * journal mode get enabled in different ways
1023 	 * So just print the value even if we didn't specify it
1024 	 */
1025 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
1026 		seq_puts(seq, ",data=journal");
1027 	else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
1028 		seq_puts(seq, ",data=ordered");
1029 	else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
1030 		seq_puts(seq, ",data=writeback");
1031 
1032 	if (sbi->s_inode_readahead_blks != EXT4_DEF_INODE_READAHEAD_BLKS)
1033 		seq_printf(seq, ",inode_readahead_blks=%u",
1034 			   sbi->s_inode_readahead_blks);
1035 
1036 	if (test_opt(sb, DATA_ERR_ABORT))
1037 		seq_puts(seq, ",data_err=abort");
1038 
1039 	if (test_opt(sb, NO_AUTO_DA_ALLOC))
1040 		seq_puts(seq, ",noauto_da_alloc");
1041 
1042 	if (test_opt(sb, DISCARD) && !(def_mount_opts & EXT4_DEFM_DISCARD))
1043 		seq_puts(seq, ",discard");
1044 
1045 	if (test_opt(sb, NOLOAD))
1046 		seq_puts(seq, ",norecovery");
1047 
1048 	if (test_opt(sb, DIOREAD_NOLOCK))
1049 		seq_puts(seq, ",dioread_nolock");
1050 
1051 	if (test_opt(sb, BLOCK_VALIDITY) &&
1052 	    !(def_mount_opts & EXT4_DEFM_BLOCK_VALIDITY))
1053 		seq_puts(seq, ",block_validity");
1054 
1055 	if (!test_opt(sb, INIT_INODE_TABLE))
1056 		seq_puts(seq, ",noinit_inode_table");
1057 	else if (sbi->s_li_wait_mult)
1058 		seq_printf(seq, ",init_inode_table=%u",
1059 			   (unsigned) sbi->s_li_wait_mult);
1060 
1061 	ext4_show_quota_options(seq, sb);
1062 
1063 	return 0;
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 				char *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 #ifdef CONFIG_QUOTA
1149 	.get_reserved_space = ext4_get_reserved_space,
1150 #endif
1151 	.write_dquot	= ext4_write_dquot,
1152 	.acquire_dquot	= ext4_acquire_dquot,
1153 	.release_dquot	= ext4_release_dquot,
1154 	.mark_dirty	= ext4_mark_dquot_dirty,
1155 	.write_info	= ext4_write_info,
1156 	.alloc_dquot	= dquot_alloc,
1157 	.destroy_dquot	= dquot_destroy,
1158 };
1159 
1160 static const struct quotactl_ops ext4_qctl_operations = {
1161 	.quota_on	= ext4_quota_on,
1162 	.quota_off	= ext4_quota_off,
1163 	.quota_sync	= dquot_quota_sync,
1164 	.get_info	= dquot_get_dqinfo,
1165 	.set_info	= dquot_set_dqinfo,
1166 	.get_dqblk	= dquot_get_dqblk,
1167 	.set_dqblk	= dquot_set_dqblk
1168 };
1169 #endif
1170 
1171 static const struct super_operations ext4_sops = {
1172 	.alloc_inode	= ext4_alloc_inode,
1173 	.destroy_inode	= ext4_destroy_inode,
1174 	.write_inode	= ext4_write_inode,
1175 	.dirty_inode	= ext4_dirty_inode,
1176 	.evict_inode	= ext4_evict_inode,
1177 	.put_super	= ext4_put_super,
1178 	.sync_fs	= ext4_sync_fs,
1179 	.freeze_fs	= ext4_freeze,
1180 	.unfreeze_fs	= ext4_unfreeze,
1181 	.statfs		= ext4_statfs,
1182 	.remount_fs	= ext4_remount,
1183 	.show_options	= ext4_show_options,
1184 #ifdef CONFIG_QUOTA
1185 	.quota_read	= ext4_quota_read,
1186 	.quota_write	= ext4_quota_write,
1187 #endif
1188 	.bdev_try_to_free_page = bdev_try_to_free_page,
1189 	.trim_fs	= ext4_trim_fs
1190 };
1191 
1192 static const struct super_operations ext4_nojournal_sops = {
1193 	.alloc_inode	= ext4_alloc_inode,
1194 	.destroy_inode	= ext4_destroy_inode,
1195 	.write_inode	= ext4_write_inode,
1196 	.dirty_inode	= ext4_dirty_inode,
1197 	.evict_inode	= ext4_evict_inode,
1198 	.write_super	= ext4_write_super,
1199 	.put_super	= ext4_put_super,
1200 	.statfs		= ext4_statfs,
1201 	.remount_fs	= ext4_remount,
1202 	.show_options	= ext4_show_options,
1203 #ifdef CONFIG_QUOTA
1204 	.quota_read	= ext4_quota_read,
1205 	.quota_write	= ext4_quota_write,
1206 #endif
1207 	.bdev_try_to_free_page = bdev_try_to_free_page,
1208 };
1209 
1210 static const struct export_operations ext4_export_ops = {
1211 	.fh_to_dentry = ext4_fh_to_dentry,
1212 	.fh_to_parent = ext4_fh_to_parent,
1213 	.get_parent = ext4_get_parent,
1214 };
1215 
1216 enum {
1217 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
1218 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
1219 	Opt_nouid32, Opt_debug, Opt_oldalloc, Opt_orlov,
1220 	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
1221 	Opt_auto_da_alloc, Opt_noauto_da_alloc, Opt_noload, Opt_nobh, Opt_bh,
1222 	Opt_commit, Opt_min_batch_time, Opt_max_batch_time,
1223 	Opt_journal_update, Opt_journal_dev,
1224 	Opt_journal_checksum, Opt_journal_async_commit,
1225 	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
1226 	Opt_data_err_abort, Opt_data_err_ignore,
1227 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
1228 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
1229 	Opt_noquota, Opt_ignore, Opt_barrier, Opt_nobarrier, Opt_err,
1230 	Opt_resize, Opt_usrquota, Opt_grpquota, Opt_i_version,
1231 	Opt_stripe, Opt_delalloc, Opt_nodelalloc,
1232 	Opt_block_validity, Opt_noblock_validity,
1233 	Opt_inode_readahead_blks, Opt_journal_ioprio,
1234 	Opt_dioread_nolock, Opt_dioread_lock,
1235 	Opt_discard, Opt_nodiscard,
1236 	Opt_init_inode_table, Opt_noinit_inode_table,
1237 };
1238 
1239 static const match_table_t tokens = {
1240 	{Opt_bsd_df, "bsddf"},
1241 	{Opt_minix_df, "minixdf"},
1242 	{Opt_grpid, "grpid"},
1243 	{Opt_grpid, "bsdgroups"},
1244 	{Opt_nogrpid, "nogrpid"},
1245 	{Opt_nogrpid, "sysvgroups"},
1246 	{Opt_resgid, "resgid=%u"},
1247 	{Opt_resuid, "resuid=%u"},
1248 	{Opt_sb, "sb=%u"},
1249 	{Opt_err_cont, "errors=continue"},
1250 	{Opt_err_panic, "errors=panic"},
1251 	{Opt_err_ro, "errors=remount-ro"},
1252 	{Opt_nouid32, "nouid32"},
1253 	{Opt_debug, "debug"},
1254 	{Opt_oldalloc, "oldalloc"},
1255 	{Opt_orlov, "orlov"},
1256 	{Opt_user_xattr, "user_xattr"},
1257 	{Opt_nouser_xattr, "nouser_xattr"},
1258 	{Opt_acl, "acl"},
1259 	{Opt_noacl, "noacl"},
1260 	{Opt_noload, "noload"},
1261 	{Opt_noload, "norecovery"},
1262 	{Opt_nobh, "nobh"},
1263 	{Opt_bh, "bh"},
1264 	{Opt_commit, "commit=%u"},
1265 	{Opt_min_batch_time, "min_batch_time=%u"},
1266 	{Opt_max_batch_time, "max_batch_time=%u"},
1267 	{Opt_journal_update, "journal=update"},
1268 	{Opt_journal_dev, "journal_dev=%u"},
1269 	{Opt_journal_checksum, "journal_checksum"},
1270 	{Opt_journal_async_commit, "journal_async_commit"},
1271 	{Opt_abort, "abort"},
1272 	{Opt_data_journal, "data=journal"},
1273 	{Opt_data_ordered, "data=ordered"},
1274 	{Opt_data_writeback, "data=writeback"},
1275 	{Opt_data_err_abort, "data_err=abort"},
1276 	{Opt_data_err_ignore, "data_err=ignore"},
1277 	{Opt_offusrjquota, "usrjquota="},
1278 	{Opt_usrjquota, "usrjquota=%s"},
1279 	{Opt_offgrpjquota, "grpjquota="},
1280 	{Opt_grpjquota, "grpjquota=%s"},
1281 	{Opt_jqfmt_vfsold, "jqfmt=vfsold"},
1282 	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
1283 	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
1284 	{Opt_grpquota, "grpquota"},
1285 	{Opt_noquota, "noquota"},
1286 	{Opt_quota, "quota"},
1287 	{Opt_usrquota, "usrquota"},
1288 	{Opt_barrier, "barrier=%u"},
1289 	{Opt_barrier, "barrier"},
1290 	{Opt_nobarrier, "nobarrier"},
1291 	{Opt_i_version, "i_version"},
1292 	{Opt_stripe, "stripe=%u"},
1293 	{Opt_resize, "resize"},
1294 	{Opt_delalloc, "delalloc"},
1295 	{Opt_nodelalloc, "nodelalloc"},
1296 	{Opt_block_validity, "block_validity"},
1297 	{Opt_noblock_validity, "noblock_validity"},
1298 	{Opt_inode_readahead_blks, "inode_readahead_blks=%u"},
1299 	{Opt_journal_ioprio, "journal_ioprio=%u"},
1300 	{Opt_auto_da_alloc, "auto_da_alloc=%u"},
1301 	{Opt_auto_da_alloc, "auto_da_alloc"},
1302 	{Opt_noauto_da_alloc, "noauto_da_alloc"},
1303 	{Opt_dioread_nolock, "dioread_nolock"},
1304 	{Opt_dioread_lock, "dioread_lock"},
1305 	{Opt_discard, "discard"},
1306 	{Opt_nodiscard, "nodiscard"},
1307 	{Opt_init_inode_table, "init_itable=%u"},
1308 	{Opt_init_inode_table, "init_itable"},
1309 	{Opt_noinit_inode_table, "noinit_itable"},
1310 	{Opt_err, NULL},
1311 };
1312 
1313 static ext4_fsblk_t get_sb_block(void **data)
1314 {
1315 	ext4_fsblk_t	sb_block;
1316 	char		*options = (char *) *data;
1317 
1318 	if (!options || strncmp(options, "sb=", 3) != 0)
1319 		return 1;	/* Default location */
1320 
1321 	options += 3;
1322 	/* TODO: use simple_strtoll with >32bit ext4 */
1323 	sb_block = simple_strtoul(options, &options, 0);
1324 	if (*options && *options != ',') {
1325 		printk(KERN_ERR "EXT4-fs: Invalid sb specification: %s\n",
1326 		       (char *) *data);
1327 		return 1;
1328 	}
1329 	if (*options == ',')
1330 		options++;
1331 	*data = (void *) options;
1332 
1333 	return sb_block;
1334 }
1335 
1336 #define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))
1337 static char deprecated_msg[] = "Mount option \"%s\" will be removed by %s\n"
1338 	"Contact linux-ext4@vger.kernel.org if you think we should keep it.\n";
1339 
1340 #ifdef CONFIG_QUOTA
1341 static int set_qf_name(struct super_block *sb, int qtype, substring_t *args)
1342 {
1343 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1344 	char *qname;
1345 
1346 	if (sb_any_quota_loaded(sb) &&
1347 		!sbi->s_qf_names[qtype]) {
1348 		ext4_msg(sb, KERN_ERR,
1349 			"Cannot change journaled "
1350 			"quota options when quota turned on");
1351 		return 0;
1352 	}
1353 	qname = match_strdup(args);
1354 	if (!qname) {
1355 		ext4_msg(sb, KERN_ERR,
1356 			"Not enough memory for storing quotafile name");
1357 		return 0;
1358 	}
1359 	if (sbi->s_qf_names[qtype] &&
1360 		strcmp(sbi->s_qf_names[qtype], qname)) {
1361 		ext4_msg(sb, KERN_ERR,
1362 			"%s quota file already specified", QTYPE2NAME(qtype));
1363 		kfree(qname);
1364 		return 0;
1365 	}
1366 	sbi->s_qf_names[qtype] = qname;
1367 	if (strchr(sbi->s_qf_names[qtype], '/')) {
1368 		ext4_msg(sb, KERN_ERR,
1369 			"quotafile must be on filesystem root");
1370 		kfree(sbi->s_qf_names[qtype]);
1371 		sbi->s_qf_names[qtype] = NULL;
1372 		return 0;
1373 	}
1374 	set_opt(sbi->s_mount_opt, QUOTA);
1375 	return 1;
1376 }
1377 
1378 static int clear_qf_name(struct super_block *sb, int qtype)
1379 {
1380 
1381 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1382 
1383 	if (sb_any_quota_loaded(sb) &&
1384 		sbi->s_qf_names[qtype]) {
1385 		ext4_msg(sb, KERN_ERR, "Cannot change journaled quota options"
1386 			" when quota turned on");
1387 		return 0;
1388 	}
1389 	/*
1390 	 * The space will be released later when all options are confirmed
1391 	 * to be correct
1392 	 */
1393 	sbi->s_qf_names[qtype] = NULL;
1394 	return 1;
1395 }
1396 #endif
1397 
1398 static int parse_options(char *options, struct super_block *sb,
1399 			 unsigned long *journal_devnum,
1400 			 unsigned int *journal_ioprio,
1401 			 ext4_fsblk_t *n_blocks_count, int is_remount)
1402 {
1403 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1404 	char *p;
1405 	substring_t args[MAX_OPT_ARGS];
1406 	int data_opt = 0;
1407 	int option;
1408 #ifdef CONFIG_QUOTA
1409 	int qfmt;
1410 #endif
1411 
1412 	if (!options)
1413 		return 1;
1414 
1415 	while ((p = strsep(&options, ",")) != NULL) {
1416 		int token;
1417 		if (!*p)
1418 			continue;
1419 
1420 		/*
1421 		 * Initialize args struct so we know whether arg was
1422 		 * found; some options take optional arguments.
1423 		 */
1424 		args[0].to = args[0].from = 0;
1425 		token = match_token(p, tokens, args);
1426 		switch (token) {
1427 		case Opt_bsd_df:
1428 			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
1429 			clear_opt(sbi->s_mount_opt, MINIX_DF);
1430 			break;
1431 		case Opt_minix_df:
1432 			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
1433 			set_opt(sbi->s_mount_opt, MINIX_DF);
1434 
1435 			break;
1436 		case Opt_grpid:
1437 			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
1438 			set_opt(sbi->s_mount_opt, GRPID);
1439 
1440 			break;
1441 		case Opt_nogrpid:
1442 			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
1443 			clear_opt(sbi->s_mount_opt, GRPID);
1444 
1445 			break;
1446 		case Opt_resuid:
1447 			if (match_int(&args[0], &option))
1448 				return 0;
1449 			sbi->s_resuid = option;
1450 			break;
1451 		case Opt_resgid:
1452 			if (match_int(&args[0], &option))
1453 				return 0;
1454 			sbi->s_resgid = option;
1455 			break;
1456 		case Opt_sb:
1457 			/* handled by get_sb_block() instead of here */
1458 			/* *sb_block = match_int(&args[0]); */
1459 			break;
1460 		case Opt_err_panic:
1461 			clear_opt(sbi->s_mount_opt, ERRORS_CONT);
1462 			clear_opt(sbi->s_mount_opt, ERRORS_RO);
1463 			set_opt(sbi->s_mount_opt, ERRORS_PANIC);
1464 			break;
1465 		case Opt_err_ro:
1466 			clear_opt(sbi->s_mount_opt, ERRORS_CONT);
1467 			clear_opt(sbi->s_mount_opt, ERRORS_PANIC);
1468 			set_opt(sbi->s_mount_opt, ERRORS_RO);
1469 			break;
1470 		case Opt_err_cont:
1471 			clear_opt(sbi->s_mount_opt, ERRORS_RO);
1472 			clear_opt(sbi->s_mount_opt, ERRORS_PANIC);
1473 			set_opt(sbi->s_mount_opt, ERRORS_CONT);
1474 			break;
1475 		case Opt_nouid32:
1476 			set_opt(sbi->s_mount_opt, NO_UID32);
1477 			break;
1478 		case Opt_debug:
1479 			set_opt(sbi->s_mount_opt, DEBUG);
1480 			break;
1481 		case Opt_oldalloc:
1482 			set_opt(sbi->s_mount_opt, OLDALLOC);
1483 			break;
1484 		case Opt_orlov:
1485 			clear_opt(sbi->s_mount_opt, OLDALLOC);
1486 			break;
1487 #ifdef CONFIG_EXT4_FS_XATTR
1488 		case Opt_user_xattr:
1489 			set_opt(sbi->s_mount_opt, XATTR_USER);
1490 			break;
1491 		case Opt_nouser_xattr:
1492 			clear_opt(sbi->s_mount_opt, XATTR_USER);
1493 			break;
1494 #else
1495 		case Opt_user_xattr:
1496 		case Opt_nouser_xattr:
1497 			ext4_msg(sb, KERN_ERR, "(no)user_xattr options not supported");
1498 			break;
1499 #endif
1500 #ifdef CONFIG_EXT4_FS_POSIX_ACL
1501 		case Opt_acl:
1502 			set_opt(sbi->s_mount_opt, POSIX_ACL);
1503 			break;
1504 		case Opt_noacl:
1505 			clear_opt(sbi->s_mount_opt, POSIX_ACL);
1506 			break;
1507 #else
1508 		case Opt_acl:
1509 		case Opt_noacl:
1510 			ext4_msg(sb, KERN_ERR, "(no)acl options not supported");
1511 			break;
1512 #endif
1513 		case Opt_journal_update:
1514 			/* @@@ FIXME */
1515 			/* Eventually we will want to be able to create
1516 			   a journal file here.  For now, only allow the
1517 			   user to specify an existing inode to be the
1518 			   journal file. */
1519 			if (is_remount) {
1520 				ext4_msg(sb, KERN_ERR,
1521 					 "Cannot specify journal on remount");
1522 				return 0;
1523 			}
1524 			set_opt(sbi->s_mount_opt, UPDATE_JOURNAL);
1525 			break;
1526 		case Opt_journal_dev:
1527 			if (is_remount) {
1528 				ext4_msg(sb, KERN_ERR,
1529 					"Cannot specify journal on remount");
1530 				return 0;
1531 			}
1532 			if (match_int(&args[0], &option))
1533 				return 0;
1534 			*journal_devnum = option;
1535 			break;
1536 		case Opt_journal_checksum:
1537 			set_opt(sbi->s_mount_opt, JOURNAL_CHECKSUM);
1538 			break;
1539 		case Opt_journal_async_commit:
1540 			set_opt(sbi->s_mount_opt, JOURNAL_ASYNC_COMMIT);
1541 			set_opt(sbi->s_mount_opt, JOURNAL_CHECKSUM);
1542 			break;
1543 		case Opt_noload:
1544 			set_opt(sbi->s_mount_opt, NOLOAD);
1545 			break;
1546 		case Opt_commit:
1547 			if (match_int(&args[0], &option))
1548 				return 0;
1549 			if (option < 0)
1550 				return 0;
1551 			if (option == 0)
1552 				option = JBD2_DEFAULT_MAX_COMMIT_AGE;
1553 			sbi->s_commit_interval = HZ * option;
1554 			break;
1555 		case Opt_max_batch_time:
1556 			if (match_int(&args[0], &option))
1557 				return 0;
1558 			if (option < 0)
1559 				return 0;
1560 			if (option == 0)
1561 				option = EXT4_DEF_MAX_BATCH_TIME;
1562 			sbi->s_max_batch_time = option;
1563 			break;
1564 		case Opt_min_batch_time:
1565 			if (match_int(&args[0], &option))
1566 				return 0;
1567 			if (option < 0)
1568 				return 0;
1569 			sbi->s_min_batch_time = option;
1570 			break;
1571 		case Opt_data_journal:
1572 			data_opt = EXT4_MOUNT_JOURNAL_DATA;
1573 			goto datacheck;
1574 		case Opt_data_ordered:
1575 			data_opt = EXT4_MOUNT_ORDERED_DATA;
1576 			goto datacheck;
1577 		case Opt_data_writeback:
1578 			data_opt = EXT4_MOUNT_WRITEBACK_DATA;
1579 		datacheck:
1580 			if (is_remount) {
1581 				if (test_opt(sb, DATA_FLAGS) != data_opt) {
1582 					ext4_msg(sb, KERN_ERR,
1583 						"Cannot change data mode on remount");
1584 					return 0;
1585 				}
1586 			} else {
1587 				clear_opt(sbi->s_mount_opt, DATA_FLAGS);
1588 				sbi->s_mount_opt |= data_opt;
1589 			}
1590 			break;
1591 		case Opt_data_err_abort:
1592 			set_opt(sbi->s_mount_opt, DATA_ERR_ABORT);
1593 			break;
1594 		case Opt_data_err_ignore:
1595 			clear_opt(sbi->s_mount_opt, DATA_ERR_ABORT);
1596 			break;
1597 #ifdef CONFIG_QUOTA
1598 		case Opt_usrjquota:
1599 			if (!set_qf_name(sb, USRQUOTA, &args[0]))
1600 				return 0;
1601 			break;
1602 		case Opt_grpjquota:
1603 			if (!set_qf_name(sb, GRPQUOTA, &args[0]))
1604 				return 0;
1605 			break;
1606 		case Opt_offusrjquota:
1607 			if (!clear_qf_name(sb, USRQUOTA))
1608 				return 0;
1609 			break;
1610 		case Opt_offgrpjquota:
1611 			if (!clear_qf_name(sb, GRPQUOTA))
1612 				return 0;
1613 			break;
1614 
1615 		case Opt_jqfmt_vfsold:
1616 			qfmt = QFMT_VFS_OLD;
1617 			goto set_qf_format;
1618 		case Opt_jqfmt_vfsv0:
1619 			qfmt = QFMT_VFS_V0;
1620 			goto set_qf_format;
1621 		case Opt_jqfmt_vfsv1:
1622 			qfmt = QFMT_VFS_V1;
1623 set_qf_format:
1624 			if (sb_any_quota_loaded(sb) &&
1625 			    sbi->s_jquota_fmt != qfmt) {
1626 				ext4_msg(sb, KERN_ERR, "Cannot change "
1627 					"journaled quota options when "
1628 					"quota turned on");
1629 				return 0;
1630 			}
1631 			sbi->s_jquota_fmt = qfmt;
1632 			break;
1633 		case Opt_quota:
1634 		case Opt_usrquota:
1635 			set_opt(sbi->s_mount_opt, QUOTA);
1636 			set_opt(sbi->s_mount_opt, USRQUOTA);
1637 			break;
1638 		case Opt_grpquota:
1639 			set_opt(sbi->s_mount_opt, QUOTA);
1640 			set_opt(sbi->s_mount_opt, GRPQUOTA);
1641 			break;
1642 		case Opt_noquota:
1643 			if (sb_any_quota_loaded(sb)) {
1644 				ext4_msg(sb, KERN_ERR, "Cannot change quota "
1645 					"options when quota turned on");
1646 				return 0;
1647 			}
1648 			clear_opt(sbi->s_mount_opt, QUOTA);
1649 			clear_opt(sbi->s_mount_opt, USRQUOTA);
1650 			clear_opt(sbi->s_mount_opt, GRPQUOTA);
1651 			break;
1652 #else
1653 		case Opt_quota:
1654 		case Opt_usrquota:
1655 		case Opt_grpquota:
1656 			ext4_msg(sb, KERN_ERR,
1657 				"quota options not supported");
1658 			break;
1659 		case Opt_usrjquota:
1660 		case Opt_grpjquota:
1661 		case Opt_offusrjquota:
1662 		case Opt_offgrpjquota:
1663 		case Opt_jqfmt_vfsold:
1664 		case Opt_jqfmt_vfsv0:
1665 		case Opt_jqfmt_vfsv1:
1666 			ext4_msg(sb, KERN_ERR,
1667 				"journaled quota options not supported");
1668 			break;
1669 		case Opt_noquota:
1670 			break;
1671 #endif
1672 		case Opt_abort:
1673 			sbi->s_mount_flags |= EXT4_MF_FS_ABORTED;
1674 			break;
1675 		case Opt_nobarrier:
1676 			clear_opt(sbi->s_mount_opt, BARRIER);
1677 			break;
1678 		case Opt_barrier:
1679 			if (args[0].from) {
1680 				if (match_int(&args[0], &option))
1681 					return 0;
1682 			} else
1683 				option = 1;	/* No argument, default to 1 */
1684 			if (option)
1685 				set_opt(sbi->s_mount_opt, BARRIER);
1686 			else
1687 				clear_opt(sbi->s_mount_opt, BARRIER);
1688 			break;
1689 		case Opt_ignore:
1690 			break;
1691 		case Opt_resize:
1692 			if (!is_remount) {
1693 				ext4_msg(sb, KERN_ERR,
1694 					"resize option only available "
1695 					"for remount");
1696 				return 0;
1697 			}
1698 			if (match_int(&args[0], &option) != 0)
1699 				return 0;
1700 			*n_blocks_count = option;
1701 			break;
1702 		case Opt_nobh:
1703 			ext4_msg(sb, KERN_WARNING,
1704 				 "Ignoring deprecated nobh option");
1705 			break;
1706 		case Opt_bh:
1707 			ext4_msg(sb, KERN_WARNING,
1708 				 "Ignoring deprecated bh option");
1709 			break;
1710 		case Opt_i_version:
1711 			set_opt(sbi->s_mount_opt, I_VERSION);
1712 			sb->s_flags |= MS_I_VERSION;
1713 			break;
1714 		case Opt_nodelalloc:
1715 			clear_opt(sbi->s_mount_opt, DELALLOC);
1716 			break;
1717 		case Opt_stripe:
1718 			if (match_int(&args[0], &option))
1719 				return 0;
1720 			if (option < 0)
1721 				return 0;
1722 			sbi->s_stripe = option;
1723 			break;
1724 		case Opt_delalloc:
1725 			set_opt(sbi->s_mount_opt, DELALLOC);
1726 			break;
1727 		case Opt_block_validity:
1728 			set_opt(sbi->s_mount_opt, BLOCK_VALIDITY);
1729 			break;
1730 		case Opt_noblock_validity:
1731 			clear_opt(sbi->s_mount_opt, BLOCK_VALIDITY);
1732 			break;
1733 		case Opt_inode_readahead_blks:
1734 			if (match_int(&args[0], &option))
1735 				return 0;
1736 			if (option < 0 || option > (1 << 30))
1737 				return 0;
1738 			if (!is_power_of_2(option)) {
1739 				ext4_msg(sb, KERN_ERR,
1740 					 "EXT4-fs: inode_readahead_blks"
1741 					 " must be a power of 2");
1742 				return 0;
1743 			}
1744 			sbi->s_inode_readahead_blks = option;
1745 			break;
1746 		case Opt_journal_ioprio:
1747 			if (match_int(&args[0], &option))
1748 				return 0;
1749 			if (option < 0 || option > 7)
1750 				break;
1751 			*journal_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE,
1752 							    option);
1753 			break;
1754 		case Opt_noauto_da_alloc:
1755 			set_opt(sbi->s_mount_opt,NO_AUTO_DA_ALLOC);
1756 			break;
1757 		case Opt_auto_da_alloc:
1758 			if (args[0].from) {
1759 				if (match_int(&args[0], &option))
1760 					return 0;
1761 			} else
1762 				option = 1;	/* No argument, default to 1 */
1763 			if (option)
1764 				clear_opt(sbi->s_mount_opt, NO_AUTO_DA_ALLOC);
1765 			else
1766 				set_opt(sbi->s_mount_opt,NO_AUTO_DA_ALLOC);
1767 			break;
1768 		case Opt_discard:
1769 			set_opt(sbi->s_mount_opt, DISCARD);
1770 			break;
1771 		case Opt_nodiscard:
1772 			clear_opt(sbi->s_mount_opt, DISCARD);
1773 			break;
1774 		case Opt_dioread_nolock:
1775 			set_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
1776 			break;
1777 		case Opt_dioread_lock:
1778 			clear_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
1779 			break;
1780 		case Opt_init_inode_table:
1781 			set_opt(sbi->s_mount_opt, INIT_INODE_TABLE);
1782 			if (args[0].from) {
1783 				if (match_int(&args[0], &option))
1784 					return 0;
1785 			} else
1786 				option = EXT4_DEF_LI_WAIT_MULT;
1787 			if (option < 0)
1788 				return 0;
1789 			sbi->s_li_wait_mult = option;
1790 			break;
1791 		case Opt_noinit_inode_table:
1792 			clear_opt(sbi->s_mount_opt, INIT_INODE_TABLE);
1793 			break;
1794 		default:
1795 			ext4_msg(sb, KERN_ERR,
1796 			       "Unrecognized mount option \"%s\" "
1797 			       "or missing value", p);
1798 			return 0;
1799 		}
1800 	}
1801 #ifdef CONFIG_QUOTA
1802 	if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
1803 		if (test_opt(sb, USRQUOTA) && sbi->s_qf_names[USRQUOTA])
1804 			clear_opt(sbi->s_mount_opt, USRQUOTA);
1805 
1806 		if (test_opt(sb, GRPQUOTA) && sbi->s_qf_names[GRPQUOTA])
1807 			clear_opt(sbi->s_mount_opt, GRPQUOTA);
1808 
1809 		if (test_opt(sb, GRPQUOTA) || test_opt(sb, USRQUOTA)) {
1810 			ext4_msg(sb, KERN_ERR, "old and new quota "
1811 					"format mixing");
1812 			return 0;
1813 		}
1814 
1815 		if (!sbi->s_jquota_fmt) {
1816 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1817 					"not specified");
1818 			return 0;
1819 		}
1820 	} else {
1821 		if (sbi->s_jquota_fmt) {
1822 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1823 					"specified with no journaling "
1824 					"enabled");
1825 			return 0;
1826 		}
1827 	}
1828 #endif
1829 	return 1;
1830 }
1831 
1832 static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
1833 			    int read_only)
1834 {
1835 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1836 	int res = 0;
1837 
1838 	if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
1839 		ext4_msg(sb, KERN_ERR, "revision level too high, "
1840 			 "forcing read-only mode");
1841 		res = MS_RDONLY;
1842 	}
1843 	if (read_only)
1844 		return res;
1845 	if (!(sbi->s_mount_state & EXT4_VALID_FS))
1846 		ext4_msg(sb, KERN_WARNING, "warning: mounting unchecked fs, "
1847 			 "running e2fsck is recommended");
1848 	else if ((sbi->s_mount_state & EXT4_ERROR_FS))
1849 		ext4_msg(sb, KERN_WARNING,
1850 			 "warning: mounting fs with errors, "
1851 			 "running e2fsck is recommended");
1852 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
1853 		 le16_to_cpu(es->s_mnt_count) >=
1854 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
1855 		ext4_msg(sb, KERN_WARNING,
1856 			 "warning: maximal mount count reached, "
1857 			 "running e2fsck is recommended");
1858 	else if (le32_to_cpu(es->s_checkinterval) &&
1859 		(le32_to_cpu(es->s_lastcheck) +
1860 			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
1861 		ext4_msg(sb, KERN_WARNING,
1862 			 "warning: checktime reached, "
1863 			 "running e2fsck is recommended");
1864 	if (!sbi->s_journal)
1865 		es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1866 	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
1867 		es->s_max_mnt_count = cpu_to_le16(EXT4_DFL_MAX_MNT_COUNT);
1868 	le16_add_cpu(&es->s_mnt_count, 1);
1869 	es->s_mtime = cpu_to_le32(get_seconds());
1870 	ext4_update_dynamic_rev(sb);
1871 	if (sbi->s_journal)
1872 		EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
1873 
1874 	ext4_commit_super(sb, 1);
1875 	if (test_opt(sb, DEBUG))
1876 		printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, "
1877 				"bpg=%lu, ipg=%lu, mo=%04x]\n",
1878 			sb->s_blocksize,
1879 			sbi->s_groups_count,
1880 			EXT4_BLOCKS_PER_GROUP(sb),
1881 			EXT4_INODES_PER_GROUP(sb),
1882 			sbi->s_mount_opt);
1883 
1884 	return res;
1885 }
1886 
1887 static int ext4_fill_flex_info(struct super_block *sb)
1888 {
1889 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1890 	struct ext4_group_desc *gdp = NULL;
1891 	ext4_group_t flex_group_count;
1892 	ext4_group_t flex_group;
1893 	int groups_per_flex = 0;
1894 	size_t size;
1895 	int i;
1896 
1897 	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
1898 	groups_per_flex = 1 << sbi->s_log_groups_per_flex;
1899 
1900 	if (groups_per_flex < 2) {
1901 		sbi->s_log_groups_per_flex = 0;
1902 		return 1;
1903 	}
1904 
1905 	/* We allocate both existing and potentially added groups */
1906 	flex_group_count = ((sbi->s_groups_count + groups_per_flex - 1) +
1907 			((le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) + 1) <<
1908 			      EXT4_DESC_PER_BLOCK_BITS(sb))) / groups_per_flex;
1909 	size = flex_group_count * sizeof(struct flex_groups);
1910 	sbi->s_flex_groups = kzalloc(size, GFP_KERNEL);
1911 	if (sbi->s_flex_groups == NULL) {
1912 		sbi->s_flex_groups = vmalloc(size);
1913 		if (sbi->s_flex_groups)
1914 			memset(sbi->s_flex_groups, 0, size);
1915 	}
1916 	if (sbi->s_flex_groups == NULL) {
1917 		ext4_msg(sb, KERN_ERR, "not enough memory for "
1918 				"%u flex groups", flex_group_count);
1919 		goto failed;
1920 	}
1921 
1922 	for (i = 0; i < sbi->s_groups_count; i++) {
1923 		gdp = ext4_get_group_desc(sb, i, NULL);
1924 
1925 		flex_group = ext4_flex_group(sbi, i);
1926 		atomic_add(ext4_free_inodes_count(sb, gdp),
1927 			   &sbi->s_flex_groups[flex_group].free_inodes);
1928 		atomic_add(ext4_free_blks_count(sb, gdp),
1929 			   &sbi->s_flex_groups[flex_group].free_blocks);
1930 		atomic_add(ext4_used_dirs_count(sb, gdp),
1931 			   &sbi->s_flex_groups[flex_group].used_dirs);
1932 	}
1933 
1934 	return 1;
1935 failed:
1936 	return 0;
1937 }
1938 
1939 __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
1940 			    struct ext4_group_desc *gdp)
1941 {
1942 	__u16 crc = 0;
1943 
1944 	if (sbi->s_es->s_feature_ro_compat &
1945 	    cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
1946 		int offset = offsetof(struct ext4_group_desc, bg_checksum);
1947 		__le32 le_group = cpu_to_le32(block_group);
1948 
1949 		crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
1950 		crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
1951 		crc = crc16(crc, (__u8 *)gdp, offset);
1952 		offset += sizeof(gdp->bg_checksum); /* skip checksum */
1953 		/* for checksum of struct ext4_group_desc do the rest...*/
1954 		if ((sbi->s_es->s_feature_incompat &
1955 		     cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) &&
1956 		    offset < le16_to_cpu(sbi->s_es->s_desc_size))
1957 			crc = crc16(crc, (__u8 *)gdp + offset,
1958 				    le16_to_cpu(sbi->s_es->s_desc_size) -
1959 					offset);
1960 	}
1961 
1962 	return cpu_to_le16(crc);
1963 }
1964 
1965 int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 block_group,
1966 				struct ext4_group_desc *gdp)
1967 {
1968 	if ((sbi->s_es->s_feature_ro_compat &
1969 	     cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) &&
1970 	    (gdp->bg_checksum != ext4_group_desc_csum(sbi, block_group, gdp)))
1971 		return 0;
1972 
1973 	return 1;
1974 }
1975 
1976 /* Called at mount-time, super-block is locked */
1977 static int ext4_check_descriptors(struct super_block *sb,
1978 				  ext4_group_t *first_not_zeroed)
1979 {
1980 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1981 	ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
1982 	ext4_fsblk_t last_block;
1983 	ext4_fsblk_t block_bitmap;
1984 	ext4_fsblk_t inode_bitmap;
1985 	ext4_fsblk_t inode_table;
1986 	int flexbg_flag = 0;
1987 	ext4_group_t i, grp = sbi->s_groups_count;
1988 
1989 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
1990 		flexbg_flag = 1;
1991 
1992 	ext4_debug("Checking group descriptors");
1993 
1994 	for (i = 0; i < sbi->s_groups_count; i++) {
1995 		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1996 
1997 		if (i == sbi->s_groups_count - 1 || flexbg_flag)
1998 			last_block = ext4_blocks_count(sbi->s_es) - 1;
1999 		else
2000 			last_block = first_block +
2001 				(EXT4_BLOCKS_PER_GROUP(sb) - 1);
2002 
2003 		if ((grp == sbi->s_groups_count) &&
2004 		   !(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2005 			grp = i;
2006 
2007 		block_bitmap = ext4_block_bitmap(sb, gdp);
2008 		if (block_bitmap < first_block || block_bitmap > last_block) {
2009 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2010 			       "Block bitmap for group %u not in group "
2011 			       "(block %llu)!", i, block_bitmap);
2012 			return 0;
2013 		}
2014 		inode_bitmap = ext4_inode_bitmap(sb, gdp);
2015 		if (inode_bitmap < first_block || inode_bitmap > last_block) {
2016 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2017 			       "Inode bitmap for group %u not in group "
2018 			       "(block %llu)!", i, inode_bitmap);
2019 			return 0;
2020 		}
2021 		inode_table = ext4_inode_table(sb, gdp);
2022 		if (inode_table < first_block ||
2023 		    inode_table + sbi->s_itb_per_group - 1 > last_block) {
2024 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2025 			       "Inode table for group %u not in group "
2026 			       "(block %llu)!", i, inode_table);
2027 			return 0;
2028 		}
2029 		ext4_lock_group(sb, i);
2030 		if (!ext4_group_desc_csum_verify(sbi, i, gdp)) {
2031 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2032 				 "Checksum for group %u failed (%u!=%u)",
2033 				 i, le16_to_cpu(ext4_group_desc_csum(sbi, i,
2034 				     gdp)), le16_to_cpu(gdp->bg_checksum));
2035 			if (!(sb->s_flags & MS_RDONLY)) {
2036 				ext4_unlock_group(sb, i);
2037 				return 0;
2038 			}
2039 		}
2040 		ext4_unlock_group(sb, i);
2041 		if (!flexbg_flag)
2042 			first_block += EXT4_BLOCKS_PER_GROUP(sb);
2043 	}
2044 	if (NULL != first_not_zeroed)
2045 		*first_not_zeroed = grp;
2046 
2047 	ext4_free_blocks_count_set(sbi->s_es, ext4_count_free_blocks(sb));
2048 	sbi->s_es->s_free_inodes_count =cpu_to_le32(ext4_count_free_inodes(sb));
2049 	return 1;
2050 }
2051 
2052 /* ext4_orphan_cleanup() walks a singly-linked list of inodes (starting at
2053  * the superblock) which were deleted from all directories, but held open by
2054  * a process at the time of a crash.  We walk the list and try to delete these
2055  * inodes at recovery time (only with a read-write filesystem).
2056  *
2057  * In order to keep the orphan inode chain consistent during traversal (in
2058  * case of crash during recovery), we link each inode into the superblock
2059  * orphan list_head and handle it the same way as an inode deletion during
2060  * normal operation (which journals the operations for us).
2061  *
2062  * We only do an iget() and an iput() on each inode, which is very safe if we
2063  * accidentally point at an in-use or already deleted inode.  The worst that
2064  * can happen in this case is that we get a "bit already cleared" message from
2065  * ext4_free_inode().  The only reason we would point at a wrong inode is if
2066  * e2fsck was run on this filesystem, and it must have already done the orphan
2067  * inode cleanup for us, so we can safely abort without any further action.
2068  */
2069 static void ext4_orphan_cleanup(struct super_block *sb,
2070 				struct ext4_super_block *es)
2071 {
2072 	unsigned int s_flags = sb->s_flags;
2073 	int nr_orphans = 0, nr_truncates = 0;
2074 #ifdef CONFIG_QUOTA
2075 	int i;
2076 #endif
2077 	if (!es->s_last_orphan) {
2078 		jbd_debug(4, "no orphan inodes to clean up\n");
2079 		return;
2080 	}
2081 
2082 	if (bdev_read_only(sb->s_bdev)) {
2083 		ext4_msg(sb, KERN_ERR, "write access "
2084 			"unavailable, skipping orphan cleanup");
2085 		return;
2086 	}
2087 
2088 	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
2089 		if (es->s_last_orphan)
2090 			jbd_debug(1, "Errors on filesystem, "
2091 				  "clearing orphan list.\n");
2092 		es->s_last_orphan = 0;
2093 		jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
2094 		return;
2095 	}
2096 
2097 	if (s_flags & MS_RDONLY) {
2098 		ext4_msg(sb, KERN_INFO, "orphan cleanup on readonly fs");
2099 		sb->s_flags &= ~MS_RDONLY;
2100 	}
2101 #ifdef CONFIG_QUOTA
2102 	/* Needed for iput() to work correctly and not trash data */
2103 	sb->s_flags |= MS_ACTIVE;
2104 	/* Turn on quotas so that they are updated correctly */
2105 	for (i = 0; i < MAXQUOTAS; i++) {
2106 		if (EXT4_SB(sb)->s_qf_names[i]) {
2107 			int ret = ext4_quota_on_mount(sb, i);
2108 			if (ret < 0)
2109 				ext4_msg(sb, KERN_ERR,
2110 					"Cannot turn on journaled "
2111 					"quota: error %d", ret);
2112 		}
2113 	}
2114 #endif
2115 
2116 	while (es->s_last_orphan) {
2117 		struct inode *inode;
2118 
2119 		inode = ext4_orphan_get(sb, le32_to_cpu(es->s_last_orphan));
2120 		if (IS_ERR(inode)) {
2121 			es->s_last_orphan = 0;
2122 			break;
2123 		}
2124 
2125 		list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
2126 		dquot_initialize(inode);
2127 		if (inode->i_nlink) {
2128 			ext4_msg(sb, KERN_DEBUG,
2129 				"%s: truncating inode %lu to %lld bytes",
2130 				__func__, inode->i_ino, inode->i_size);
2131 			jbd_debug(2, "truncating inode %lu to %lld bytes\n",
2132 				  inode->i_ino, inode->i_size);
2133 			ext4_truncate(inode);
2134 			nr_truncates++;
2135 		} else {
2136 			ext4_msg(sb, KERN_DEBUG,
2137 				"%s: deleting unreferenced inode %lu",
2138 				__func__, inode->i_ino);
2139 			jbd_debug(2, "deleting unreferenced inode %lu\n",
2140 				  inode->i_ino);
2141 			nr_orphans++;
2142 		}
2143 		iput(inode);  /* The delete magic happens here! */
2144 	}
2145 
2146 #define PLURAL(x) (x), ((x) == 1) ? "" : "s"
2147 
2148 	if (nr_orphans)
2149 		ext4_msg(sb, KERN_INFO, "%d orphan inode%s deleted",
2150 		       PLURAL(nr_orphans));
2151 	if (nr_truncates)
2152 		ext4_msg(sb, KERN_INFO, "%d truncate%s cleaned up",
2153 		       PLURAL(nr_truncates));
2154 #ifdef CONFIG_QUOTA
2155 	/* Turn quotas off */
2156 	for (i = 0; i < MAXQUOTAS; i++) {
2157 		if (sb_dqopt(sb)->files[i])
2158 			dquot_quota_off(sb, i);
2159 	}
2160 #endif
2161 	sb->s_flags = s_flags; /* Restore MS_RDONLY status */
2162 }
2163 
2164 /*
2165  * Maximal extent format file size.
2166  * Resulting logical blkno at s_maxbytes must fit in our on-disk
2167  * extent format containers, within a sector_t, and within i_blocks
2168  * in the vfs.  ext4 inode has 48 bits of i_block in fsblock units,
2169  * so that won't be a limiting factor.
2170  *
2171  * Note, this does *not* consider any metadata overhead for vfs i_blocks.
2172  */
2173 static loff_t ext4_max_size(int blkbits, int has_huge_files)
2174 {
2175 	loff_t res;
2176 	loff_t upper_limit = MAX_LFS_FILESIZE;
2177 
2178 	/* small i_blocks in vfs inode? */
2179 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2180 		/*
2181 		 * CONFIG_LBDAF is not enabled implies the inode
2182 		 * i_block represent total blocks in 512 bytes
2183 		 * 32 == size of vfs inode i_blocks * 8
2184 		 */
2185 		upper_limit = (1LL << 32) - 1;
2186 
2187 		/* total blocks in file system block size */
2188 		upper_limit >>= (blkbits - 9);
2189 		upper_limit <<= blkbits;
2190 	}
2191 
2192 	/* 32-bit extent-start container, ee_block */
2193 	res = 1LL << 32;
2194 	res <<= blkbits;
2195 	res -= 1;
2196 
2197 	/* Sanity check against vm- & vfs- imposed limits */
2198 	if (res > upper_limit)
2199 		res = upper_limit;
2200 
2201 	return res;
2202 }
2203 
2204 /*
2205  * Maximal bitmap file size.  There is a direct, and {,double-,triple-}indirect
2206  * block limit, and also a limit of (2^48 - 1) 512-byte sectors in i_blocks.
2207  * We need to be 1 filesystem block less than the 2^48 sector limit.
2208  */
2209 static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
2210 {
2211 	loff_t res = EXT4_NDIR_BLOCKS;
2212 	int meta_blocks;
2213 	loff_t upper_limit;
2214 	/* This is calculated to be the largest file size for a dense, block
2215 	 * mapped file such that the file's total number of 512-byte sectors,
2216 	 * including data and all indirect blocks, does not exceed (2^48 - 1).
2217 	 *
2218 	 * __u32 i_blocks_lo and _u16 i_blocks_high represent the total
2219 	 * number of 512-byte sectors of the file.
2220 	 */
2221 
2222 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2223 		/*
2224 		 * !has_huge_files or CONFIG_LBDAF not enabled implies that
2225 		 * the inode i_block field represents total file blocks in
2226 		 * 2^32 512-byte sectors == size of vfs inode i_blocks * 8
2227 		 */
2228 		upper_limit = (1LL << 32) - 1;
2229 
2230 		/* total blocks in file system block size */
2231 		upper_limit >>= (bits - 9);
2232 
2233 	} else {
2234 		/*
2235 		 * We use 48 bit ext4_inode i_blocks
2236 		 * With EXT4_HUGE_FILE_FL set the i_blocks
2237 		 * represent total number of blocks in
2238 		 * file system block size
2239 		 */
2240 		upper_limit = (1LL << 48) - 1;
2241 
2242 	}
2243 
2244 	/* indirect blocks */
2245 	meta_blocks = 1;
2246 	/* double indirect blocks */
2247 	meta_blocks += 1 + (1LL << (bits-2));
2248 	/* tripple indirect blocks */
2249 	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
2250 
2251 	upper_limit -= meta_blocks;
2252 	upper_limit <<= bits;
2253 
2254 	res += 1LL << (bits-2);
2255 	res += 1LL << (2*(bits-2));
2256 	res += 1LL << (3*(bits-2));
2257 	res <<= bits;
2258 	if (res > upper_limit)
2259 		res = upper_limit;
2260 
2261 	if (res > MAX_LFS_FILESIZE)
2262 		res = MAX_LFS_FILESIZE;
2263 
2264 	return res;
2265 }
2266 
2267 static ext4_fsblk_t descriptor_loc(struct super_block *sb,
2268 				   ext4_fsblk_t logical_sb_block, int nr)
2269 {
2270 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2271 	ext4_group_t bg, first_meta_bg;
2272 	int has_super = 0;
2273 
2274 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
2275 
2276 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
2277 	    nr < first_meta_bg)
2278 		return logical_sb_block + nr + 1;
2279 	bg = sbi->s_desc_per_block * nr;
2280 	if (ext4_bg_has_super(sb, bg))
2281 		has_super = 1;
2282 
2283 	return (has_super + ext4_group_first_block_no(sb, bg));
2284 }
2285 
2286 /**
2287  * ext4_get_stripe_size: Get the stripe size.
2288  * @sbi: In memory super block info
2289  *
2290  * If we have specified it via mount option, then
2291  * use the mount option value. If the value specified at mount time is
2292  * greater than the blocks per group use the super block value.
2293  * If the super block value is greater than blocks per group return 0.
2294  * Allocator needs it be less than blocks per group.
2295  *
2296  */
2297 static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi)
2298 {
2299 	unsigned long stride = le16_to_cpu(sbi->s_es->s_raid_stride);
2300 	unsigned long stripe_width =
2301 			le32_to_cpu(sbi->s_es->s_raid_stripe_width);
2302 
2303 	if (sbi->s_stripe && sbi->s_stripe <= sbi->s_blocks_per_group)
2304 		return sbi->s_stripe;
2305 
2306 	if (stripe_width <= sbi->s_blocks_per_group)
2307 		return stripe_width;
2308 
2309 	if (stride <= sbi->s_blocks_per_group)
2310 		return stride;
2311 
2312 	return 0;
2313 }
2314 
2315 /* sysfs supprt */
2316 
2317 struct ext4_attr {
2318 	struct attribute attr;
2319 	ssize_t (*show)(struct ext4_attr *, struct ext4_sb_info *, char *);
2320 	ssize_t (*store)(struct ext4_attr *, struct ext4_sb_info *,
2321 			 const char *, size_t);
2322 	int offset;
2323 };
2324 
2325 static int parse_strtoul(const char *buf,
2326 		unsigned long max, unsigned long *value)
2327 {
2328 	char *endp;
2329 
2330 	*value = simple_strtoul(skip_spaces(buf), &endp, 0);
2331 	endp = skip_spaces(endp);
2332 	if (*endp || *value > max)
2333 		return -EINVAL;
2334 
2335 	return 0;
2336 }
2337 
2338 static ssize_t delayed_allocation_blocks_show(struct ext4_attr *a,
2339 					      struct ext4_sb_info *sbi,
2340 					      char *buf)
2341 {
2342 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2343 			(s64) percpu_counter_sum(&sbi->s_dirtyblocks_counter));
2344 }
2345 
2346 static ssize_t session_write_kbytes_show(struct ext4_attr *a,
2347 					 struct ext4_sb_info *sbi, char *buf)
2348 {
2349 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
2350 
2351 	if (!sb->s_bdev->bd_part)
2352 		return snprintf(buf, PAGE_SIZE, "0\n");
2353 	return snprintf(buf, PAGE_SIZE, "%lu\n",
2354 			(part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
2355 			 sbi->s_sectors_written_start) >> 1);
2356 }
2357 
2358 static ssize_t lifetime_write_kbytes_show(struct ext4_attr *a,
2359 					  struct ext4_sb_info *sbi, char *buf)
2360 {
2361 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
2362 
2363 	if (!sb->s_bdev->bd_part)
2364 		return snprintf(buf, PAGE_SIZE, "0\n");
2365 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2366 			(unsigned long long)(sbi->s_kbytes_written +
2367 			((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
2368 			  EXT4_SB(sb)->s_sectors_written_start) >> 1)));
2369 }
2370 
2371 static ssize_t inode_readahead_blks_store(struct ext4_attr *a,
2372 					  struct ext4_sb_info *sbi,
2373 					  const char *buf, size_t count)
2374 {
2375 	unsigned long t;
2376 
2377 	if (parse_strtoul(buf, 0x40000000, &t))
2378 		return -EINVAL;
2379 
2380 	if (!is_power_of_2(t))
2381 		return -EINVAL;
2382 
2383 	sbi->s_inode_readahead_blks = t;
2384 	return count;
2385 }
2386 
2387 static ssize_t sbi_ui_show(struct ext4_attr *a,
2388 			   struct ext4_sb_info *sbi, char *buf)
2389 {
2390 	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
2391 
2392 	return snprintf(buf, PAGE_SIZE, "%u\n", *ui);
2393 }
2394 
2395 static ssize_t sbi_ui_store(struct ext4_attr *a,
2396 			    struct ext4_sb_info *sbi,
2397 			    const char *buf, size_t count)
2398 {
2399 	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
2400 	unsigned long t;
2401 
2402 	if (parse_strtoul(buf, 0xffffffff, &t))
2403 		return -EINVAL;
2404 	*ui = t;
2405 	return count;
2406 }
2407 
2408 #define EXT4_ATTR_OFFSET(_name,_mode,_show,_store,_elname) \
2409 static struct ext4_attr ext4_attr_##_name = {			\
2410 	.attr = {.name = __stringify(_name), .mode = _mode },	\
2411 	.show	= _show,					\
2412 	.store	= _store,					\
2413 	.offset = offsetof(struct ext4_sb_info, _elname),	\
2414 }
2415 #define EXT4_ATTR(name, mode, show, store) \
2416 static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store)
2417 
2418 #define EXT4_INFO_ATTR(name) EXT4_ATTR(name, 0444, NULL, NULL)
2419 #define EXT4_RO_ATTR(name) EXT4_ATTR(name, 0444, name##_show, NULL)
2420 #define EXT4_RW_ATTR(name) EXT4_ATTR(name, 0644, name##_show, name##_store)
2421 #define EXT4_RW_ATTR_SBI_UI(name, elname)	\
2422 	EXT4_ATTR_OFFSET(name, 0644, sbi_ui_show, sbi_ui_store, elname)
2423 #define ATTR_LIST(name) &ext4_attr_##name.attr
2424 
2425 EXT4_RO_ATTR(delayed_allocation_blocks);
2426 EXT4_RO_ATTR(session_write_kbytes);
2427 EXT4_RO_ATTR(lifetime_write_kbytes);
2428 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, sbi_ui_show,
2429 		 inode_readahead_blks_store, s_inode_readahead_blks);
2430 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
2431 EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
2432 EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
2433 EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
2434 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
2435 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
2436 EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
2437 EXT4_RW_ATTR_SBI_UI(max_writeback_mb_bump, s_max_writeback_mb_bump);
2438 
2439 static struct attribute *ext4_attrs[] = {
2440 	ATTR_LIST(delayed_allocation_blocks),
2441 	ATTR_LIST(session_write_kbytes),
2442 	ATTR_LIST(lifetime_write_kbytes),
2443 	ATTR_LIST(inode_readahead_blks),
2444 	ATTR_LIST(inode_goal),
2445 	ATTR_LIST(mb_stats),
2446 	ATTR_LIST(mb_max_to_scan),
2447 	ATTR_LIST(mb_min_to_scan),
2448 	ATTR_LIST(mb_order2_req),
2449 	ATTR_LIST(mb_stream_req),
2450 	ATTR_LIST(mb_group_prealloc),
2451 	ATTR_LIST(max_writeback_mb_bump),
2452 	NULL,
2453 };
2454 
2455 /* Features this copy of ext4 supports */
2456 EXT4_INFO_ATTR(lazy_itable_init);
2457 EXT4_INFO_ATTR(batched_discard);
2458 
2459 static struct attribute *ext4_feat_attrs[] = {
2460 	ATTR_LIST(lazy_itable_init),
2461 	ATTR_LIST(batched_discard),
2462 	NULL,
2463 };
2464 
2465 static ssize_t ext4_attr_show(struct kobject *kobj,
2466 			      struct attribute *attr, char *buf)
2467 {
2468 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2469 						s_kobj);
2470 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
2471 
2472 	return a->show ? a->show(a, sbi, buf) : 0;
2473 }
2474 
2475 static ssize_t ext4_attr_store(struct kobject *kobj,
2476 			       struct attribute *attr,
2477 			       const char *buf, size_t len)
2478 {
2479 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2480 						s_kobj);
2481 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
2482 
2483 	return a->store ? a->store(a, sbi, buf, len) : 0;
2484 }
2485 
2486 static void ext4_sb_release(struct kobject *kobj)
2487 {
2488 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2489 						s_kobj);
2490 	complete(&sbi->s_kobj_unregister);
2491 }
2492 
2493 static const struct sysfs_ops ext4_attr_ops = {
2494 	.show	= ext4_attr_show,
2495 	.store	= ext4_attr_store,
2496 };
2497 
2498 static struct kobj_type ext4_ktype = {
2499 	.default_attrs	= ext4_attrs,
2500 	.sysfs_ops	= &ext4_attr_ops,
2501 	.release	= ext4_sb_release,
2502 };
2503 
2504 static void ext4_feat_release(struct kobject *kobj)
2505 {
2506 	complete(&ext4_feat->f_kobj_unregister);
2507 }
2508 
2509 static struct kobj_type ext4_feat_ktype = {
2510 	.default_attrs	= ext4_feat_attrs,
2511 	.sysfs_ops	= &ext4_attr_ops,
2512 	.release	= ext4_feat_release,
2513 };
2514 
2515 /*
2516  * Check whether this filesystem can be mounted based on
2517  * the features present and the RDONLY/RDWR mount requested.
2518  * Returns 1 if this filesystem can be mounted as requested,
2519  * 0 if it cannot be.
2520  */
2521 static int ext4_feature_set_ok(struct super_block *sb, int readonly)
2522 {
2523 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT4_FEATURE_INCOMPAT_SUPP)) {
2524 		ext4_msg(sb, KERN_ERR,
2525 			"Couldn't mount because of "
2526 			"unsupported optional features (%x)",
2527 			(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_incompat) &
2528 			~EXT4_FEATURE_INCOMPAT_SUPP));
2529 		return 0;
2530 	}
2531 
2532 	if (readonly)
2533 		return 1;
2534 
2535 	/* Check that feature set is OK for a read-write mount */
2536 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT4_FEATURE_RO_COMPAT_SUPP)) {
2537 		ext4_msg(sb, KERN_ERR, "couldn't mount RDWR because of "
2538 			 "unsupported optional features (%x)",
2539 			 (le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_ro_compat) &
2540 				~EXT4_FEATURE_RO_COMPAT_SUPP));
2541 		return 0;
2542 	}
2543 	/*
2544 	 * Large file size enabled file system can only be mounted
2545 	 * read-write on 32-bit systems if kernel is built with CONFIG_LBDAF
2546 	 */
2547 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
2548 		if (sizeof(blkcnt_t) < sizeof(u64)) {
2549 			ext4_msg(sb, KERN_ERR, "Filesystem with huge files "
2550 				 "cannot be mounted RDWR without "
2551 				 "CONFIG_LBDAF");
2552 			return 0;
2553 		}
2554 	}
2555 	return 1;
2556 }
2557 
2558 /*
2559  * This function is called once a day if we have errors logged
2560  * on the file system
2561  */
2562 static void print_daily_error_info(unsigned long arg)
2563 {
2564 	struct super_block *sb = (struct super_block *) arg;
2565 	struct ext4_sb_info *sbi;
2566 	struct ext4_super_block *es;
2567 
2568 	sbi = EXT4_SB(sb);
2569 	es = sbi->s_es;
2570 
2571 	if (es->s_error_count)
2572 		ext4_msg(sb, KERN_NOTICE, "error count: %u",
2573 			 le32_to_cpu(es->s_error_count));
2574 	if (es->s_first_error_time) {
2575 		printk(KERN_NOTICE "EXT4-fs (%s): initial error at %u: %.*s:%d",
2576 		       sb->s_id, le32_to_cpu(es->s_first_error_time),
2577 		       (int) sizeof(es->s_first_error_func),
2578 		       es->s_first_error_func,
2579 		       le32_to_cpu(es->s_first_error_line));
2580 		if (es->s_first_error_ino)
2581 			printk(": inode %u",
2582 			       le32_to_cpu(es->s_first_error_ino));
2583 		if (es->s_first_error_block)
2584 			printk(": block %llu", (unsigned long long)
2585 			       le64_to_cpu(es->s_first_error_block));
2586 		printk("\n");
2587 	}
2588 	if (es->s_last_error_time) {
2589 		printk(KERN_NOTICE "EXT4-fs (%s): last error at %u: %.*s:%d",
2590 		       sb->s_id, le32_to_cpu(es->s_last_error_time),
2591 		       (int) sizeof(es->s_last_error_func),
2592 		       es->s_last_error_func,
2593 		       le32_to_cpu(es->s_last_error_line));
2594 		if (es->s_last_error_ino)
2595 			printk(": inode %u",
2596 			       le32_to_cpu(es->s_last_error_ino));
2597 		if (es->s_last_error_block)
2598 			printk(": block %llu", (unsigned long long)
2599 			       le64_to_cpu(es->s_last_error_block));
2600 		printk("\n");
2601 	}
2602 	mod_timer(&sbi->s_err_report, jiffies + 24*60*60*HZ);  /* Once a day */
2603 }
2604 
2605 static void ext4_lazyinode_timeout(unsigned long data)
2606 {
2607 	struct task_struct *p = (struct task_struct *)data;
2608 	wake_up_process(p);
2609 }
2610 
2611 /* Find next suitable group and run ext4_init_inode_table */
2612 static int ext4_run_li_request(struct ext4_li_request *elr)
2613 {
2614 	struct ext4_group_desc *gdp = NULL;
2615 	ext4_group_t group, ngroups;
2616 	struct super_block *sb;
2617 	unsigned long timeout = 0;
2618 	int ret = 0;
2619 
2620 	sb = elr->lr_super;
2621 	ngroups = EXT4_SB(sb)->s_groups_count;
2622 
2623 	for (group = elr->lr_next_group; group < ngroups; group++) {
2624 		gdp = ext4_get_group_desc(sb, group, NULL);
2625 		if (!gdp) {
2626 			ret = 1;
2627 			break;
2628 		}
2629 
2630 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2631 			break;
2632 	}
2633 
2634 	if (group == ngroups)
2635 		ret = 1;
2636 
2637 	if (!ret) {
2638 		timeout = jiffies;
2639 		ret = ext4_init_inode_table(sb, group,
2640 					    elr->lr_timeout ? 0 : 1);
2641 		if (elr->lr_timeout == 0) {
2642 			timeout = jiffies - timeout;
2643 			if (elr->lr_sbi->s_li_wait_mult)
2644 				timeout *= elr->lr_sbi->s_li_wait_mult;
2645 			else
2646 				timeout *= 20;
2647 			elr->lr_timeout = timeout;
2648 		}
2649 		elr->lr_next_sched = jiffies + elr->lr_timeout;
2650 		elr->lr_next_group = group + 1;
2651 	}
2652 
2653 	return ret;
2654 }
2655 
2656 /*
2657  * Remove lr_request from the list_request and free the
2658  * request tructure. Should be called with li_list_mtx held
2659  */
2660 static void ext4_remove_li_request(struct ext4_li_request *elr)
2661 {
2662 	struct ext4_sb_info *sbi;
2663 
2664 	if (!elr)
2665 		return;
2666 
2667 	sbi = elr->lr_sbi;
2668 
2669 	list_del(&elr->lr_request);
2670 	sbi->s_li_request = NULL;
2671 	kfree(elr);
2672 }
2673 
2674 static void ext4_unregister_li_request(struct super_block *sb)
2675 {
2676 	struct ext4_li_request *elr = EXT4_SB(sb)->s_li_request;
2677 
2678 	if (!ext4_li_info)
2679 		return;
2680 
2681 	mutex_lock(&ext4_li_info->li_list_mtx);
2682 	ext4_remove_li_request(elr);
2683 	mutex_unlock(&ext4_li_info->li_list_mtx);
2684 }
2685 
2686 /*
2687  * This is the function where ext4lazyinit thread lives. It walks
2688  * through the request list searching for next scheduled filesystem.
2689  * When such a fs is found, run the lazy initialization request
2690  * (ext4_rn_li_request) and keep track of the time spend in this
2691  * function. Based on that time we compute next schedule time of
2692  * the request. When walking through the list is complete, compute
2693  * next waking time and put itself into sleep.
2694  */
2695 static int ext4_lazyinit_thread(void *arg)
2696 {
2697 	struct ext4_lazy_init *eli = (struct ext4_lazy_init *)arg;
2698 	struct list_head *pos, *n;
2699 	struct ext4_li_request *elr;
2700 	unsigned long next_wakeup;
2701 	DEFINE_WAIT(wait);
2702 	int ret;
2703 
2704 	BUG_ON(NULL == eli);
2705 
2706 	eli->li_timer.data = (unsigned long)current;
2707 	eli->li_timer.function = ext4_lazyinode_timeout;
2708 
2709 	eli->li_task = current;
2710 	wake_up(&eli->li_wait_task);
2711 
2712 cont_thread:
2713 	while (true) {
2714 		next_wakeup = MAX_JIFFY_OFFSET;
2715 
2716 		mutex_lock(&eli->li_list_mtx);
2717 		if (list_empty(&eli->li_request_list)) {
2718 			mutex_unlock(&eli->li_list_mtx);
2719 			goto exit_thread;
2720 		}
2721 
2722 		list_for_each_safe(pos, n, &eli->li_request_list) {
2723 			elr = list_entry(pos, struct ext4_li_request,
2724 					 lr_request);
2725 
2726 			if (time_after_eq(jiffies, elr->lr_next_sched))
2727 				ret = ext4_run_li_request(elr);
2728 
2729 			if (ret) {
2730 				ret = 0;
2731 				ext4_remove_li_request(elr);
2732 				continue;
2733 			}
2734 
2735 			if (time_before(elr->lr_next_sched, next_wakeup))
2736 				next_wakeup = elr->lr_next_sched;
2737 		}
2738 		mutex_unlock(&eli->li_list_mtx);
2739 
2740 		if (freezing(current))
2741 			refrigerator();
2742 
2743 		if (time_after_eq(jiffies, next_wakeup)) {
2744 			cond_resched();
2745 			continue;
2746 		}
2747 
2748 		eli->li_timer.expires = next_wakeup;
2749 		add_timer(&eli->li_timer);
2750 		prepare_to_wait(&eli->li_wait_daemon, &wait,
2751 				TASK_INTERRUPTIBLE);
2752 		if (time_before(jiffies, next_wakeup))
2753 			schedule();
2754 		finish_wait(&eli->li_wait_daemon, &wait);
2755 	}
2756 
2757 exit_thread:
2758 	/*
2759 	 * It looks like the request list is empty, but we need
2760 	 * to check it under the li_list_mtx lock, to prevent any
2761 	 * additions into it, and of course we should lock ext4_li_mtx
2762 	 * to atomically free the list and ext4_li_info, because at
2763 	 * this point another ext4 filesystem could be registering
2764 	 * new one.
2765 	 */
2766 	mutex_lock(&ext4_li_mtx);
2767 	mutex_lock(&eli->li_list_mtx);
2768 	if (!list_empty(&eli->li_request_list)) {
2769 		mutex_unlock(&eli->li_list_mtx);
2770 		mutex_unlock(&ext4_li_mtx);
2771 		goto cont_thread;
2772 	}
2773 	mutex_unlock(&eli->li_list_mtx);
2774 	del_timer_sync(&ext4_li_info->li_timer);
2775 	eli->li_task = NULL;
2776 	wake_up(&eli->li_wait_task);
2777 
2778 	kfree(ext4_li_info);
2779 	ext4_li_info = NULL;
2780 	mutex_unlock(&ext4_li_mtx);
2781 
2782 	return 0;
2783 }
2784 
2785 static void ext4_clear_request_list(void)
2786 {
2787 	struct list_head *pos, *n;
2788 	struct ext4_li_request *elr;
2789 
2790 	mutex_lock(&ext4_li_info->li_list_mtx);
2791 	if (list_empty(&ext4_li_info->li_request_list))
2792 		return;
2793 
2794 	list_for_each_safe(pos, n, &ext4_li_info->li_request_list) {
2795 		elr = list_entry(pos, struct ext4_li_request,
2796 				 lr_request);
2797 		ext4_remove_li_request(elr);
2798 	}
2799 	mutex_unlock(&ext4_li_info->li_list_mtx);
2800 }
2801 
2802 static int ext4_run_lazyinit_thread(void)
2803 {
2804 	struct task_struct *t;
2805 
2806 	t = kthread_run(ext4_lazyinit_thread, ext4_li_info, "ext4lazyinit");
2807 	if (IS_ERR(t)) {
2808 		int err = PTR_ERR(t);
2809 		ext4_clear_request_list();
2810 		del_timer_sync(&ext4_li_info->li_timer);
2811 		kfree(ext4_li_info);
2812 		ext4_li_info = NULL;
2813 		printk(KERN_CRIT "EXT4: error %d creating inode table "
2814 				 "initialization thread\n",
2815 				 err);
2816 		return err;
2817 	}
2818 	ext4_li_info->li_state |= EXT4_LAZYINIT_RUNNING;
2819 
2820 	wait_event(ext4_li_info->li_wait_task, ext4_li_info->li_task != NULL);
2821 	return 0;
2822 }
2823 
2824 /*
2825  * Check whether it make sense to run itable init. thread or not.
2826  * If there is at least one uninitialized inode table, return
2827  * corresponding group number, else the loop goes through all
2828  * groups and return total number of groups.
2829  */
2830 static ext4_group_t ext4_has_uninit_itable(struct super_block *sb)
2831 {
2832 	ext4_group_t group, ngroups = EXT4_SB(sb)->s_groups_count;
2833 	struct ext4_group_desc *gdp = NULL;
2834 
2835 	for (group = 0; group < ngroups; group++) {
2836 		gdp = ext4_get_group_desc(sb, group, NULL);
2837 		if (!gdp)
2838 			continue;
2839 
2840 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2841 			break;
2842 	}
2843 
2844 	return group;
2845 }
2846 
2847 static int ext4_li_info_new(void)
2848 {
2849 	struct ext4_lazy_init *eli = NULL;
2850 
2851 	eli = kzalloc(sizeof(*eli), GFP_KERNEL);
2852 	if (!eli)
2853 		return -ENOMEM;
2854 
2855 	eli->li_task = NULL;
2856 	INIT_LIST_HEAD(&eli->li_request_list);
2857 	mutex_init(&eli->li_list_mtx);
2858 
2859 	init_waitqueue_head(&eli->li_wait_daemon);
2860 	init_waitqueue_head(&eli->li_wait_task);
2861 	init_timer(&eli->li_timer);
2862 	eli->li_state |= EXT4_LAZYINIT_QUIT;
2863 
2864 	ext4_li_info = eli;
2865 
2866 	return 0;
2867 }
2868 
2869 static struct ext4_li_request *ext4_li_request_new(struct super_block *sb,
2870 					    ext4_group_t start)
2871 {
2872 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2873 	struct ext4_li_request *elr;
2874 	unsigned long rnd;
2875 
2876 	elr = kzalloc(sizeof(*elr), GFP_KERNEL);
2877 	if (!elr)
2878 		return NULL;
2879 
2880 	elr->lr_super = sb;
2881 	elr->lr_sbi = sbi;
2882 	elr->lr_next_group = start;
2883 
2884 	/*
2885 	 * Randomize first schedule time of the request to
2886 	 * spread the inode table initialization requests
2887 	 * better.
2888 	 */
2889 	get_random_bytes(&rnd, sizeof(rnd));
2890 	elr->lr_next_sched = jiffies + (unsigned long)rnd %
2891 			     (EXT4_DEF_LI_MAX_START_DELAY * HZ);
2892 
2893 	return elr;
2894 }
2895 
2896 static int ext4_register_li_request(struct super_block *sb,
2897 				    ext4_group_t first_not_zeroed)
2898 {
2899 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2900 	struct ext4_li_request *elr;
2901 	ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
2902 	int ret;
2903 
2904 	if (sbi->s_li_request != NULL)
2905 		return 0;
2906 
2907 	if (first_not_zeroed == ngroups ||
2908 	    (sb->s_flags & MS_RDONLY) ||
2909 	    !test_opt(sb, INIT_INODE_TABLE)) {
2910 		sbi->s_li_request = NULL;
2911 		return 0;
2912 	}
2913 
2914 	if (first_not_zeroed == ngroups) {
2915 		sbi->s_li_request = NULL;
2916 		return 0;
2917 	}
2918 
2919 	elr = ext4_li_request_new(sb, first_not_zeroed);
2920 	if (!elr)
2921 		return -ENOMEM;
2922 
2923 	mutex_lock(&ext4_li_mtx);
2924 
2925 	if (NULL == ext4_li_info) {
2926 		ret = ext4_li_info_new();
2927 		if (ret)
2928 			goto out;
2929 	}
2930 
2931 	mutex_lock(&ext4_li_info->li_list_mtx);
2932 	list_add(&elr->lr_request, &ext4_li_info->li_request_list);
2933 	mutex_unlock(&ext4_li_info->li_list_mtx);
2934 
2935 	sbi->s_li_request = elr;
2936 
2937 	if (!(ext4_li_info->li_state & EXT4_LAZYINIT_RUNNING)) {
2938 		ret = ext4_run_lazyinit_thread();
2939 		if (ret)
2940 			goto out;
2941 	}
2942 out:
2943 	mutex_unlock(&ext4_li_mtx);
2944 	if (ret)
2945 		kfree(elr);
2946 	return ret;
2947 }
2948 
2949 /*
2950  * We do not need to lock anything since this is called on
2951  * module unload.
2952  */
2953 static void ext4_destroy_lazyinit_thread(void)
2954 {
2955 	/*
2956 	 * If thread exited earlier
2957 	 * there's nothing to be done.
2958 	 */
2959 	if (!ext4_li_info)
2960 		return;
2961 
2962 	ext4_clear_request_list();
2963 
2964 	while (ext4_li_info->li_task) {
2965 		wake_up(&ext4_li_info->li_wait_daemon);
2966 		wait_event(ext4_li_info->li_wait_task,
2967 			   ext4_li_info->li_task == NULL);
2968 	}
2969 }
2970 
2971 static int ext4_fill_super(struct super_block *sb, void *data, int silent)
2972 				__releases(kernel_lock)
2973 				__acquires(kernel_lock)
2974 {
2975 	char *orig_data = kstrdup(data, GFP_KERNEL);
2976 	struct buffer_head *bh;
2977 	struct ext4_super_block *es = NULL;
2978 	struct ext4_sb_info *sbi;
2979 	ext4_fsblk_t block;
2980 	ext4_fsblk_t sb_block = get_sb_block(&data);
2981 	ext4_fsblk_t logical_sb_block;
2982 	unsigned long offset = 0;
2983 	unsigned long journal_devnum = 0;
2984 	unsigned long def_mount_opts;
2985 	struct inode *root;
2986 	char *cp;
2987 	const char *descr;
2988 	int ret = -ENOMEM;
2989 	int blocksize;
2990 	unsigned int db_count;
2991 	unsigned int i;
2992 	int needs_recovery, has_huge_files;
2993 	__u64 blocks_count;
2994 	int err;
2995 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
2996 	ext4_group_t first_not_zeroed;
2997 
2998 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
2999 	if (!sbi)
3000 		goto out_free_orig;
3001 
3002 	sbi->s_blockgroup_lock =
3003 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
3004 	if (!sbi->s_blockgroup_lock) {
3005 		kfree(sbi);
3006 		goto out_free_orig;
3007 	}
3008 	sb->s_fs_info = sbi;
3009 	sbi->s_mount_opt = 0;
3010 	sbi->s_resuid = EXT4_DEF_RESUID;
3011 	sbi->s_resgid = EXT4_DEF_RESGID;
3012 	sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
3013 	sbi->s_sb_block = sb_block;
3014 	if (sb->s_bdev->bd_part)
3015 		sbi->s_sectors_written_start =
3016 			part_stat_read(sb->s_bdev->bd_part, sectors[1]);
3017 
3018 	/* Cleanup superblock name */
3019 	for (cp = sb->s_id; (cp = strchr(cp, '/'));)
3020 		*cp = '!';
3021 
3022 	ret = -EINVAL;
3023 	blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
3024 	if (!blocksize) {
3025 		ext4_msg(sb, KERN_ERR, "unable to set blocksize");
3026 		goto out_fail;
3027 	}
3028 
3029 	/*
3030 	 * The ext4 superblock will not be buffer aligned for other than 1kB
3031 	 * block sizes.  We need to calculate the offset from buffer start.
3032 	 */
3033 	if (blocksize != EXT4_MIN_BLOCK_SIZE) {
3034 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3035 		offset = do_div(logical_sb_block, blocksize);
3036 	} else {
3037 		logical_sb_block = sb_block;
3038 	}
3039 
3040 	if (!(bh = sb_bread(sb, logical_sb_block))) {
3041 		ext4_msg(sb, KERN_ERR, "unable to read superblock");
3042 		goto out_fail;
3043 	}
3044 	/*
3045 	 * Note: s_es must be initialized as soon as possible because
3046 	 *       some ext4 macro-instructions depend on its value
3047 	 */
3048 	es = (struct ext4_super_block *) (((char *)bh->b_data) + offset);
3049 	sbi->s_es = es;
3050 	sb->s_magic = le16_to_cpu(es->s_magic);
3051 	if (sb->s_magic != EXT4_SUPER_MAGIC)
3052 		goto cantfind_ext4;
3053 	sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
3054 
3055 	/* Set defaults before we parse the mount options */
3056 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
3057 	set_opt(sbi->s_mount_opt, INIT_INODE_TABLE);
3058 	if (def_mount_opts & EXT4_DEFM_DEBUG)
3059 		set_opt(sbi->s_mount_opt, DEBUG);
3060 	if (def_mount_opts & EXT4_DEFM_BSDGROUPS) {
3061 		ext4_msg(sb, KERN_WARNING, deprecated_msg, "bsdgroups",
3062 			"2.6.38");
3063 		set_opt(sbi->s_mount_opt, GRPID);
3064 	}
3065 	if (def_mount_opts & EXT4_DEFM_UID16)
3066 		set_opt(sbi->s_mount_opt, NO_UID32);
3067 #ifdef CONFIG_EXT4_FS_XATTR
3068 	if (def_mount_opts & EXT4_DEFM_XATTR_USER)
3069 		set_opt(sbi->s_mount_opt, XATTR_USER);
3070 #endif
3071 #ifdef CONFIG_EXT4_FS_POSIX_ACL
3072 	if (def_mount_opts & EXT4_DEFM_ACL)
3073 		set_opt(sbi->s_mount_opt, POSIX_ACL);
3074 #endif
3075 	if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA)
3076 		set_opt(sbi->s_mount_opt, JOURNAL_DATA);
3077 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_ORDERED)
3078 		set_opt(sbi->s_mount_opt, ORDERED_DATA);
3079 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_WBACK)
3080 		set_opt(sbi->s_mount_opt, WRITEBACK_DATA);
3081 
3082 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_PANIC)
3083 		set_opt(sbi->s_mount_opt, ERRORS_PANIC);
3084 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_CONTINUE)
3085 		set_opt(sbi->s_mount_opt, ERRORS_CONT);
3086 	else
3087 		set_opt(sbi->s_mount_opt, ERRORS_RO);
3088 	if (def_mount_opts & EXT4_DEFM_BLOCK_VALIDITY)
3089 		set_opt(sbi->s_mount_opt, BLOCK_VALIDITY);
3090 	if (def_mount_opts & EXT4_DEFM_DISCARD)
3091 		set_opt(sbi->s_mount_opt, DISCARD);
3092 
3093 	sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
3094 	sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
3095 	sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ;
3096 	sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;
3097 	sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;
3098 
3099 	if ((def_mount_opts & EXT4_DEFM_NOBARRIER) == 0)
3100 		set_opt(sbi->s_mount_opt, BARRIER);
3101 
3102 	/*
3103 	 * enable delayed allocation by default
3104 	 * Use -o nodelalloc to turn it off
3105 	 */
3106 	if (!IS_EXT3_SB(sb) &&
3107 	    ((def_mount_opts & EXT4_DEFM_NODELALLOC) == 0))
3108 		set_opt(sbi->s_mount_opt, DELALLOC);
3109 
3110 	if (!parse_options((char *) sbi->s_es->s_mount_opts, sb,
3111 			   &journal_devnum, &journal_ioprio, NULL, 0)) {
3112 		ext4_msg(sb, KERN_WARNING,
3113 			 "failed to parse options in superblock: %s",
3114 			 sbi->s_es->s_mount_opts);
3115 	}
3116 	if (!parse_options((char *) data, sb, &journal_devnum,
3117 			   &journal_ioprio, NULL, 0))
3118 		goto failed_mount;
3119 
3120 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
3121 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
3122 
3123 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
3124 	    (EXT4_HAS_COMPAT_FEATURE(sb, ~0U) ||
3125 	     EXT4_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
3126 	     EXT4_HAS_INCOMPAT_FEATURE(sb, ~0U)))
3127 		ext4_msg(sb, KERN_WARNING,
3128 		       "feature flags set on rev 0 fs, "
3129 		       "running e2fsck is recommended");
3130 
3131 	/*
3132 	 * Check feature flags regardless of the revision level, since we
3133 	 * previously didn't change the revision level when setting the flags,
3134 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
3135 	 */
3136 	if (!ext4_feature_set_ok(sb, (sb->s_flags & MS_RDONLY)))
3137 		goto failed_mount;
3138 
3139 	blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
3140 
3141 	if (blocksize < EXT4_MIN_BLOCK_SIZE ||
3142 	    blocksize > EXT4_MAX_BLOCK_SIZE) {
3143 		ext4_msg(sb, KERN_ERR,
3144 		       "Unsupported filesystem blocksize %d", blocksize);
3145 		goto failed_mount;
3146 	}
3147 
3148 	if (sb->s_blocksize != blocksize) {
3149 		/* Validate the filesystem blocksize */
3150 		if (!sb_set_blocksize(sb, blocksize)) {
3151 			ext4_msg(sb, KERN_ERR, "bad block size %d",
3152 					blocksize);
3153 			goto failed_mount;
3154 		}
3155 
3156 		brelse(bh);
3157 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3158 		offset = do_div(logical_sb_block, blocksize);
3159 		bh = sb_bread(sb, logical_sb_block);
3160 		if (!bh) {
3161 			ext4_msg(sb, KERN_ERR,
3162 			       "Can't read superblock on 2nd try");
3163 			goto failed_mount;
3164 		}
3165 		es = (struct ext4_super_block *)(((char *)bh->b_data) + offset);
3166 		sbi->s_es = es;
3167 		if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
3168 			ext4_msg(sb, KERN_ERR,
3169 			       "Magic mismatch, very weird!");
3170 			goto failed_mount;
3171 		}
3172 	}
3173 
3174 	has_huge_files = EXT4_HAS_RO_COMPAT_FEATURE(sb,
3175 				EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
3176 	sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits,
3177 						      has_huge_files);
3178 	sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits, has_huge_files);
3179 
3180 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) {
3181 		sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE;
3182 		sbi->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
3183 	} else {
3184 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
3185 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
3186 		if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
3187 		    (!is_power_of_2(sbi->s_inode_size)) ||
3188 		    (sbi->s_inode_size > blocksize)) {
3189 			ext4_msg(sb, KERN_ERR,
3190 			       "unsupported inode size: %d",
3191 			       sbi->s_inode_size);
3192 			goto failed_mount;
3193 		}
3194 		if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE)
3195 			sb->s_time_gran = 1 << (EXT4_EPOCH_BITS - 2);
3196 	}
3197 
3198 	sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
3199 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT)) {
3200 		if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT ||
3201 		    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
3202 		    !is_power_of_2(sbi->s_desc_size)) {
3203 			ext4_msg(sb, KERN_ERR,
3204 			       "unsupported descriptor size %lu",
3205 			       sbi->s_desc_size);
3206 			goto failed_mount;
3207 		}
3208 	} else
3209 		sbi->s_desc_size = EXT4_MIN_DESC_SIZE;
3210 
3211 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
3212 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
3213 	if (EXT4_INODE_SIZE(sb) == 0 || EXT4_INODES_PER_GROUP(sb) == 0)
3214 		goto cantfind_ext4;
3215 
3216 	sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
3217 	if (sbi->s_inodes_per_block == 0)
3218 		goto cantfind_ext4;
3219 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
3220 					sbi->s_inodes_per_block;
3221 	sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
3222 	sbi->s_sbh = bh;
3223 	sbi->s_mount_state = le16_to_cpu(es->s_state);
3224 	sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
3225 	sbi->s_desc_per_block_bits = ilog2(EXT4_DESC_PER_BLOCK(sb));
3226 
3227 	for (i = 0; i < 4; i++)
3228 		sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
3229 	sbi->s_def_hash_version = es->s_def_hash_version;
3230 	i = le32_to_cpu(es->s_flags);
3231 	if (i & EXT2_FLAGS_UNSIGNED_HASH)
3232 		sbi->s_hash_unsigned = 3;
3233 	else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) {
3234 #ifdef __CHAR_UNSIGNED__
3235 		es->s_flags |= cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH);
3236 		sbi->s_hash_unsigned = 3;
3237 #else
3238 		es->s_flags |= cpu_to_le32(EXT2_FLAGS_SIGNED_HASH);
3239 #endif
3240 		sb->s_dirt = 1;
3241 	}
3242 
3243 	if (sbi->s_blocks_per_group > blocksize * 8) {
3244 		ext4_msg(sb, KERN_ERR,
3245 		       "#blocks per group too big: %lu",
3246 		       sbi->s_blocks_per_group);
3247 		goto failed_mount;
3248 	}
3249 	if (sbi->s_inodes_per_group > blocksize * 8) {
3250 		ext4_msg(sb, KERN_ERR,
3251 		       "#inodes per group too big: %lu",
3252 		       sbi->s_inodes_per_group);
3253 		goto failed_mount;
3254 	}
3255 
3256 	/*
3257 	 * Test whether we have more sectors than will fit in sector_t,
3258 	 * and whether the max offset is addressable by the page cache.
3259 	 */
3260 	ret = generic_check_addressable(sb->s_blocksize_bits,
3261 					ext4_blocks_count(es));
3262 	if (ret) {
3263 		ext4_msg(sb, KERN_ERR, "filesystem"
3264 			 " too large to mount safely on this system");
3265 		if (sizeof(sector_t) < 8)
3266 			ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled");
3267 		goto failed_mount;
3268 	}
3269 
3270 	if (EXT4_BLOCKS_PER_GROUP(sb) == 0)
3271 		goto cantfind_ext4;
3272 
3273 	/* check blocks count against device size */
3274 	blocks_count = sb->s_bdev->bd_inode->i_size >> sb->s_blocksize_bits;
3275 	if (blocks_count && ext4_blocks_count(es) > blocks_count) {
3276 		ext4_msg(sb, KERN_WARNING, "bad geometry: block count %llu "
3277 		       "exceeds size of device (%llu blocks)",
3278 		       ext4_blocks_count(es), blocks_count);
3279 		goto failed_mount;
3280 	}
3281 
3282 	/*
3283 	 * It makes no sense for the first data block to be beyond the end
3284 	 * of the filesystem.
3285 	 */
3286 	if (le32_to_cpu(es->s_first_data_block) >= ext4_blocks_count(es)) {
3287                 ext4_msg(sb, KERN_WARNING, "bad geometry: first data"
3288 			 "block %u is beyond end of filesystem (%llu)",
3289 			 le32_to_cpu(es->s_first_data_block),
3290 			 ext4_blocks_count(es));
3291 		goto failed_mount;
3292 	}
3293 	blocks_count = (ext4_blocks_count(es) -
3294 			le32_to_cpu(es->s_first_data_block) +
3295 			EXT4_BLOCKS_PER_GROUP(sb) - 1);
3296 	do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
3297 	if (blocks_count > ((uint64_t)1<<32) - EXT4_DESC_PER_BLOCK(sb)) {
3298 		ext4_msg(sb, KERN_WARNING, "groups count too large: %u "
3299 		       "(block count %llu, first data block %u, "
3300 		       "blocks per group %lu)", sbi->s_groups_count,
3301 		       ext4_blocks_count(es),
3302 		       le32_to_cpu(es->s_first_data_block),
3303 		       EXT4_BLOCKS_PER_GROUP(sb));
3304 		goto failed_mount;
3305 	}
3306 	sbi->s_groups_count = blocks_count;
3307 	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
3308 			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
3309 	db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
3310 		   EXT4_DESC_PER_BLOCK(sb);
3311 	sbi->s_group_desc = kmalloc(db_count * sizeof(struct buffer_head *),
3312 				    GFP_KERNEL);
3313 	if (sbi->s_group_desc == NULL) {
3314 		ext4_msg(sb, KERN_ERR, "not enough memory");
3315 		goto failed_mount;
3316 	}
3317 
3318 #ifdef CONFIG_PROC_FS
3319 	if (ext4_proc_root)
3320 		sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
3321 #endif
3322 
3323 	bgl_lock_init(sbi->s_blockgroup_lock);
3324 
3325 	for (i = 0; i < db_count; i++) {
3326 		block = descriptor_loc(sb, logical_sb_block, i);
3327 		sbi->s_group_desc[i] = sb_bread(sb, block);
3328 		if (!sbi->s_group_desc[i]) {
3329 			ext4_msg(sb, KERN_ERR,
3330 			       "can't read group descriptor %d", i);
3331 			db_count = i;
3332 			goto failed_mount2;
3333 		}
3334 	}
3335 	if (!ext4_check_descriptors(sb, &first_not_zeroed)) {
3336 		ext4_msg(sb, KERN_ERR, "group descriptors corrupted!");
3337 		goto failed_mount2;
3338 	}
3339 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
3340 		if (!ext4_fill_flex_info(sb)) {
3341 			ext4_msg(sb, KERN_ERR,
3342 			       "unable to initialize "
3343 			       "flex_bg meta info!");
3344 			goto failed_mount2;
3345 		}
3346 
3347 	sbi->s_gdb_count = db_count;
3348 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
3349 	spin_lock_init(&sbi->s_next_gen_lock);
3350 
3351 	sbi->s_stripe = ext4_get_stripe_size(sbi);
3352 	sbi->s_max_writeback_mb_bump = 128;
3353 
3354 	/*
3355 	 * set up enough so that it can read an inode
3356 	 */
3357 	if (!test_opt(sb, NOLOAD) &&
3358 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL))
3359 		sb->s_op = &ext4_sops;
3360 	else
3361 		sb->s_op = &ext4_nojournal_sops;
3362 	sb->s_export_op = &ext4_export_ops;
3363 	sb->s_xattr = ext4_xattr_handlers;
3364 #ifdef CONFIG_QUOTA
3365 	sb->s_qcop = &ext4_qctl_operations;
3366 	sb->dq_op = &ext4_quota_operations;
3367 #endif
3368 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
3369 	mutex_init(&sbi->s_orphan_lock);
3370 	mutex_init(&sbi->s_resize_lock);
3371 
3372 	sb->s_root = NULL;
3373 
3374 	needs_recovery = (es->s_last_orphan != 0 ||
3375 			  EXT4_HAS_INCOMPAT_FEATURE(sb,
3376 				    EXT4_FEATURE_INCOMPAT_RECOVER));
3377 
3378 	/*
3379 	 * The first inode we look at is the journal inode.  Don't try
3380 	 * root first: it may be modified in the journal!
3381 	 */
3382 	if (!test_opt(sb, NOLOAD) &&
3383 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
3384 		if (ext4_load_journal(sb, es, journal_devnum))
3385 			goto failed_mount3;
3386 	} else if (test_opt(sb, NOLOAD) && !(sb->s_flags & MS_RDONLY) &&
3387 	      EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
3388 		ext4_msg(sb, KERN_ERR, "required journal recovery "
3389 		       "suppressed and not mounted read-only");
3390 		goto failed_mount_wq;
3391 	} else {
3392 		clear_opt(sbi->s_mount_opt, DATA_FLAGS);
3393 		set_opt(sbi->s_mount_opt, WRITEBACK_DATA);
3394 		sbi->s_journal = NULL;
3395 		needs_recovery = 0;
3396 		goto no_journal;
3397 	}
3398 
3399 	if (ext4_blocks_count(es) > 0xffffffffULL &&
3400 	    !jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
3401 				       JBD2_FEATURE_INCOMPAT_64BIT)) {
3402 		ext4_msg(sb, KERN_ERR, "Failed to set 64-bit journal feature");
3403 		goto failed_mount_wq;
3404 	}
3405 
3406 	if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
3407 		jbd2_journal_set_features(sbi->s_journal,
3408 				JBD2_FEATURE_COMPAT_CHECKSUM, 0,
3409 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
3410 	} else if (test_opt(sb, JOURNAL_CHECKSUM)) {
3411 		jbd2_journal_set_features(sbi->s_journal,
3412 				JBD2_FEATURE_COMPAT_CHECKSUM, 0, 0);
3413 		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
3414 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
3415 	} else {
3416 		jbd2_journal_clear_features(sbi->s_journal,
3417 				JBD2_FEATURE_COMPAT_CHECKSUM, 0,
3418 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
3419 	}
3420 
3421 	/* We have now updated the journal if required, so we can
3422 	 * validate the data journaling mode. */
3423 	switch (test_opt(sb, DATA_FLAGS)) {
3424 	case 0:
3425 		/* No mode set, assume a default based on the journal
3426 		 * capabilities: ORDERED_DATA if the journal can
3427 		 * cope, else JOURNAL_DATA
3428 		 */
3429 		if (jbd2_journal_check_available_features
3430 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE))
3431 			set_opt(sbi->s_mount_opt, ORDERED_DATA);
3432 		else
3433 			set_opt(sbi->s_mount_opt, JOURNAL_DATA);
3434 		break;
3435 
3436 	case EXT4_MOUNT_ORDERED_DATA:
3437 	case EXT4_MOUNT_WRITEBACK_DATA:
3438 		if (!jbd2_journal_check_available_features
3439 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
3440 			ext4_msg(sb, KERN_ERR, "Journal does not support "
3441 			       "requested data journaling mode");
3442 			goto failed_mount_wq;
3443 		}
3444 	default:
3445 		break;
3446 	}
3447 	set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
3448 
3449 no_journal:
3450 	err = percpu_counter_init(&sbi->s_freeblocks_counter,
3451 				  ext4_count_free_blocks(sb));
3452 	if (!err)
3453 		err = percpu_counter_init(&sbi->s_freeinodes_counter,
3454 					  ext4_count_free_inodes(sb));
3455 	if (!err)
3456 		err = percpu_counter_init(&sbi->s_dirs_counter,
3457 					  ext4_count_dirs(sb));
3458 	if (!err)
3459 		err = percpu_counter_init(&sbi->s_dirtyblocks_counter, 0);
3460 	if (err) {
3461 		ext4_msg(sb, KERN_ERR, "insufficient memory");
3462 		goto failed_mount_wq;
3463 	}
3464 
3465 	EXT4_SB(sb)->dio_unwritten_wq = create_workqueue("ext4-dio-unwritten");
3466 	if (!EXT4_SB(sb)->dio_unwritten_wq) {
3467 		printk(KERN_ERR "EXT4-fs: failed to create DIO workqueue\n");
3468 		goto failed_mount_wq;
3469 	}
3470 
3471 	/*
3472 	 * The jbd2_journal_load will have done any necessary log recovery,
3473 	 * so we can safely mount the rest of the filesystem now.
3474 	 */
3475 
3476 	root = ext4_iget(sb, EXT4_ROOT_INO);
3477 	if (IS_ERR(root)) {
3478 		ext4_msg(sb, KERN_ERR, "get root inode failed");
3479 		ret = PTR_ERR(root);
3480 		goto failed_mount4;
3481 	}
3482 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
3483 		iput(root);
3484 		ext4_msg(sb, KERN_ERR, "corrupt root inode, run e2fsck");
3485 		goto failed_mount4;
3486 	}
3487 	sb->s_root = d_alloc_root(root);
3488 	if (!sb->s_root) {
3489 		ext4_msg(sb, KERN_ERR, "get root dentry failed");
3490 		iput(root);
3491 		ret = -ENOMEM;
3492 		goto failed_mount4;
3493 	}
3494 
3495 	ext4_setup_super(sb, es, sb->s_flags & MS_RDONLY);
3496 
3497 	/* determine the minimum size of new large inodes, if present */
3498 	if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
3499 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
3500 						     EXT4_GOOD_OLD_INODE_SIZE;
3501 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3502 				       EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE)) {
3503 			if (sbi->s_want_extra_isize <
3504 			    le16_to_cpu(es->s_want_extra_isize))
3505 				sbi->s_want_extra_isize =
3506 					le16_to_cpu(es->s_want_extra_isize);
3507 			if (sbi->s_want_extra_isize <
3508 			    le16_to_cpu(es->s_min_extra_isize))
3509 				sbi->s_want_extra_isize =
3510 					le16_to_cpu(es->s_min_extra_isize);
3511 		}
3512 	}
3513 	/* Check if enough inode space is available */
3514 	if (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize >
3515 							sbi->s_inode_size) {
3516 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
3517 						       EXT4_GOOD_OLD_INODE_SIZE;
3518 		ext4_msg(sb, KERN_INFO, "required extra inode space not"
3519 			 "available");
3520 	}
3521 
3522 	if (test_opt(sb, DELALLOC) &&
3523 	    (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)) {
3524 		ext4_msg(sb, KERN_WARNING, "Ignoring delalloc option - "
3525 			 "requested data journaling mode");
3526 		clear_opt(sbi->s_mount_opt, DELALLOC);
3527 	}
3528 	if (test_opt(sb, DIOREAD_NOLOCK)) {
3529 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
3530 			ext4_msg(sb, KERN_WARNING, "Ignoring dioread_nolock "
3531 				"option - requested data journaling mode");
3532 			clear_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
3533 		}
3534 		if (sb->s_blocksize < PAGE_SIZE) {
3535 			ext4_msg(sb, KERN_WARNING, "Ignoring dioread_nolock "
3536 				"option - block size is too small");
3537 			clear_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
3538 		}
3539 	}
3540 
3541 	err = ext4_setup_system_zone(sb);
3542 	if (err) {
3543 		ext4_msg(sb, KERN_ERR, "failed to initialize system "
3544 			 "zone (%d)", err);
3545 		goto failed_mount4;
3546 	}
3547 
3548 	ext4_ext_init(sb);
3549 	err = ext4_mb_init(sb, needs_recovery);
3550 	if (err) {
3551 		ext4_msg(sb, KERN_ERR, "failed to initialize mballoc (%d)",
3552 			 err);
3553 		goto failed_mount4;
3554 	}
3555 
3556 	err = ext4_register_li_request(sb, first_not_zeroed);
3557 	if (err)
3558 		goto failed_mount4;
3559 
3560 	sbi->s_kobj.kset = ext4_kset;
3561 	init_completion(&sbi->s_kobj_unregister);
3562 	err = kobject_init_and_add(&sbi->s_kobj, &ext4_ktype, NULL,
3563 				   "%s", sb->s_id);
3564 	if (err) {
3565 		ext4_mb_release(sb);
3566 		ext4_ext_release(sb);
3567 		goto failed_mount4;
3568 	};
3569 
3570 	EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
3571 	ext4_orphan_cleanup(sb, es);
3572 	EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
3573 	if (needs_recovery) {
3574 		ext4_msg(sb, KERN_INFO, "recovery complete");
3575 		ext4_mark_recovery_complete(sb, es);
3576 	}
3577 	if (EXT4_SB(sb)->s_journal) {
3578 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
3579 			descr = " journalled data mode";
3580 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
3581 			descr = " ordered data mode";
3582 		else
3583 			descr = " writeback data mode";
3584 	} else
3585 		descr = "out journal";
3586 
3587 	ext4_msg(sb, KERN_INFO, "mounted filesystem with%s. "
3588 		 "Opts: %s%s%s", descr, sbi->s_es->s_mount_opts,
3589 		 *sbi->s_es->s_mount_opts ? "; " : "", orig_data);
3590 
3591 	init_timer(&sbi->s_err_report);
3592 	sbi->s_err_report.function = print_daily_error_info;
3593 	sbi->s_err_report.data = (unsigned long) sb;
3594 	if (es->s_error_count)
3595 		mod_timer(&sbi->s_err_report, jiffies + 300*HZ); /* 5 minutes */
3596 
3597 	kfree(orig_data);
3598 	return 0;
3599 
3600 cantfind_ext4:
3601 	if (!silent)
3602 		ext4_msg(sb, KERN_ERR, "VFS: Can't find ext4 filesystem");
3603 	goto failed_mount;
3604 
3605 failed_mount4:
3606 	ext4_msg(sb, KERN_ERR, "mount failed");
3607 	destroy_workqueue(EXT4_SB(sb)->dio_unwritten_wq);
3608 failed_mount_wq:
3609 	ext4_release_system_zone(sb);
3610 	if (sbi->s_journal) {
3611 		jbd2_journal_destroy(sbi->s_journal);
3612 		sbi->s_journal = NULL;
3613 	}
3614 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
3615 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
3616 	percpu_counter_destroy(&sbi->s_dirs_counter);
3617 	percpu_counter_destroy(&sbi->s_dirtyblocks_counter);
3618 failed_mount3:
3619 	if (sbi->s_flex_groups) {
3620 		if (is_vmalloc_addr(sbi->s_flex_groups))
3621 			vfree(sbi->s_flex_groups);
3622 		else
3623 			kfree(sbi->s_flex_groups);
3624 	}
3625 failed_mount2:
3626 	for (i = 0; i < db_count; i++)
3627 		brelse(sbi->s_group_desc[i]);
3628 	kfree(sbi->s_group_desc);
3629 failed_mount:
3630 	if (sbi->s_proc) {
3631 		remove_proc_entry(sb->s_id, ext4_proc_root);
3632 	}
3633 #ifdef CONFIG_QUOTA
3634 	for (i = 0; i < MAXQUOTAS; i++)
3635 		kfree(sbi->s_qf_names[i]);
3636 #endif
3637 	ext4_blkdev_remove(sbi);
3638 	brelse(bh);
3639 out_fail:
3640 	sb->s_fs_info = NULL;
3641 	kfree(sbi->s_blockgroup_lock);
3642 	kfree(sbi);
3643 out_free_orig:
3644 	kfree(orig_data);
3645 	return ret;
3646 }
3647 
3648 /*
3649  * Setup any per-fs journal parameters now.  We'll do this both on
3650  * initial mount, once the journal has been initialised but before we've
3651  * done any recovery; and again on any subsequent remount.
3652  */
3653 static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
3654 {
3655 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3656 
3657 	journal->j_commit_interval = sbi->s_commit_interval;
3658 	journal->j_min_batch_time = sbi->s_min_batch_time;
3659 	journal->j_max_batch_time = sbi->s_max_batch_time;
3660 
3661 	write_lock(&journal->j_state_lock);
3662 	if (test_opt(sb, BARRIER))
3663 		journal->j_flags |= JBD2_BARRIER;
3664 	else
3665 		journal->j_flags &= ~JBD2_BARRIER;
3666 	if (test_opt(sb, DATA_ERR_ABORT))
3667 		journal->j_flags |= JBD2_ABORT_ON_SYNCDATA_ERR;
3668 	else
3669 		journal->j_flags &= ~JBD2_ABORT_ON_SYNCDATA_ERR;
3670 	write_unlock(&journal->j_state_lock);
3671 }
3672 
3673 static journal_t *ext4_get_journal(struct super_block *sb,
3674 				   unsigned int journal_inum)
3675 {
3676 	struct inode *journal_inode;
3677 	journal_t *journal;
3678 
3679 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
3680 
3681 	/* First, test for the existence of a valid inode on disk.  Bad
3682 	 * things happen if we iget() an unused inode, as the subsequent
3683 	 * iput() will try to delete it. */
3684 
3685 	journal_inode = ext4_iget(sb, journal_inum);
3686 	if (IS_ERR(journal_inode)) {
3687 		ext4_msg(sb, KERN_ERR, "no journal found");
3688 		return NULL;
3689 	}
3690 	if (!journal_inode->i_nlink) {
3691 		make_bad_inode(journal_inode);
3692 		iput(journal_inode);
3693 		ext4_msg(sb, KERN_ERR, "journal inode is deleted");
3694 		return NULL;
3695 	}
3696 
3697 	jbd_debug(2, "Journal inode found at %p: %lld bytes\n",
3698 		  journal_inode, journal_inode->i_size);
3699 	if (!S_ISREG(journal_inode->i_mode)) {
3700 		ext4_msg(sb, KERN_ERR, "invalid journal inode");
3701 		iput(journal_inode);
3702 		return NULL;
3703 	}
3704 
3705 	journal = jbd2_journal_init_inode(journal_inode);
3706 	if (!journal) {
3707 		ext4_msg(sb, KERN_ERR, "Could not load journal inode");
3708 		iput(journal_inode);
3709 		return NULL;
3710 	}
3711 	journal->j_private = sb;
3712 	ext4_init_journal_params(sb, journal);
3713 	return journal;
3714 }
3715 
3716 static journal_t *ext4_get_dev_journal(struct super_block *sb,
3717 				       dev_t j_dev)
3718 {
3719 	struct buffer_head *bh;
3720 	journal_t *journal;
3721 	ext4_fsblk_t start;
3722 	ext4_fsblk_t len;
3723 	int hblock, blocksize;
3724 	ext4_fsblk_t sb_block;
3725 	unsigned long offset;
3726 	struct ext4_super_block *es;
3727 	struct block_device *bdev;
3728 
3729 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
3730 
3731 	bdev = ext4_blkdev_get(j_dev, sb);
3732 	if (bdev == NULL)
3733 		return NULL;
3734 
3735 	if (bd_claim(bdev, sb)) {
3736 		ext4_msg(sb, KERN_ERR,
3737 			"failed to claim external journal device");
3738 		blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
3739 		return NULL;
3740 	}
3741 
3742 	blocksize = sb->s_blocksize;
3743 	hblock = bdev_logical_block_size(bdev);
3744 	if (blocksize < hblock) {
3745 		ext4_msg(sb, KERN_ERR,
3746 			"blocksize too small for journal device");
3747 		goto out_bdev;
3748 	}
3749 
3750 	sb_block = EXT4_MIN_BLOCK_SIZE / blocksize;
3751 	offset = EXT4_MIN_BLOCK_SIZE % blocksize;
3752 	set_blocksize(bdev, blocksize);
3753 	if (!(bh = __bread(bdev, sb_block, blocksize))) {
3754 		ext4_msg(sb, KERN_ERR, "couldn't read superblock of "
3755 		       "external journal");
3756 		goto out_bdev;
3757 	}
3758 
3759 	es = (struct ext4_super_block *) (((char *)bh->b_data) + offset);
3760 	if ((le16_to_cpu(es->s_magic) != EXT4_SUPER_MAGIC) ||
3761 	    !(le32_to_cpu(es->s_feature_incompat) &
3762 	      EXT4_FEATURE_INCOMPAT_JOURNAL_DEV)) {
3763 		ext4_msg(sb, KERN_ERR, "external journal has "
3764 					"bad superblock");
3765 		brelse(bh);
3766 		goto out_bdev;
3767 	}
3768 
3769 	if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
3770 		ext4_msg(sb, KERN_ERR, "journal UUID does not match");
3771 		brelse(bh);
3772 		goto out_bdev;
3773 	}
3774 
3775 	len = ext4_blocks_count(es);
3776 	start = sb_block + 1;
3777 	brelse(bh);	/* we're done with the superblock */
3778 
3779 	journal = jbd2_journal_init_dev(bdev, sb->s_bdev,
3780 					start, len, blocksize);
3781 	if (!journal) {
3782 		ext4_msg(sb, KERN_ERR, "failed to create device journal");
3783 		goto out_bdev;
3784 	}
3785 	journal->j_private = sb;
3786 	ll_rw_block(READ, 1, &journal->j_sb_buffer);
3787 	wait_on_buffer(journal->j_sb_buffer);
3788 	if (!buffer_uptodate(journal->j_sb_buffer)) {
3789 		ext4_msg(sb, KERN_ERR, "I/O error on journal device");
3790 		goto out_journal;
3791 	}
3792 	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
3793 		ext4_msg(sb, KERN_ERR, "External journal has more than one "
3794 					"user (unsupported) - %d",
3795 			be32_to_cpu(journal->j_superblock->s_nr_users));
3796 		goto out_journal;
3797 	}
3798 	EXT4_SB(sb)->journal_bdev = bdev;
3799 	ext4_init_journal_params(sb, journal);
3800 	return journal;
3801 
3802 out_journal:
3803 	jbd2_journal_destroy(journal);
3804 out_bdev:
3805 	ext4_blkdev_put(bdev);
3806 	return NULL;
3807 }
3808 
3809 static int ext4_load_journal(struct super_block *sb,
3810 			     struct ext4_super_block *es,
3811 			     unsigned long journal_devnum)
3812 {
3813 	journal_t *journal;
3814 	unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
3815 	dev_t journal_dev;
3816 	int err = 0;
3817 	int really_read_only;
3818 
3819 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
3820 
3821 	if (journal_devnum &&
3822 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
3823 		ext4_msg(sb, KERN_INFO, "external journal device major/minor "
3824 			"numbers have changed");
3825 		journal_dev = new_decode_dev(journal_devnum);
3826 	} else
3827 		journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));
3828 
3829 	really_read_only = bdev_read_only(sb->s_bdev);
3830 
3831 	/*
3832 	 * Are we loading a blank journal or performing recovery after a
3833 	 * crash?  For recovery, we need to check in advance whether we
3834 	 * can get read-write access to the device.
3835 	 */
3836 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
3837 		if (sb->s_flags & MS_RDONLY) {
3838 			ext4_msg(sb, KERN_INFO, "INFO: recovery "
3839 					"required on readonly filesystem");
3840 			if (really_read_only) {
3841 				ext4_msg(sb, KERN_ERR, "write access "
3842 					"unavailable, cannot proceed");
3843 				return -EROFS;
3844 			}
3845 			ext4_msg(sb, KERN_INFO, "write access will "
3846 			       "be enabled during recovery");
3847 		}
3848 	}
3849 
3850 	if (journal_inum && journal_dev) {
3851 		ext4_msg(sb, KERN_ERR, "filesystem has both journal "
3852 		       "and inode journals!");
3853 		return -EINVAL;
3854 	}
3855 
3856 	if (journal_inum) {
3857 		if (!(journal = ext4_get_journal(sb, journal_inum)))
3858 			return -EINVAL;
3859 	} else {
3860 		if (!(journal = ext4_get_dev_journal(sb, journal_dev)))
3861 			return -EINVAL;
3862 	}
3863 
3864 	if (!(journal->j_flags & JBD2_BARRIER))
3865 		ext4_msg(sb, KERN_INFO, "barriers disabled");
3866 
3867 	if (!really_read_only && test_opt(sb, UPDATE_JOURNAL)) {
3868 		err = jbd2_journal_update_format(journal);
3869 		if (err)  {
3870 			ext4_msg(sb, KERN_ERR, "error updating journal");
3871 			jbd2_journal_destroy(journal);
3872 			return err;
3873 		}
3874 	}
3875 
3876 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER))
3877 		err = jbd2_journal_wipe(journal, !really_read_only);
3878 	if (!err) {
3879 		char *save = kmalloc(EXT4_S_ERR_LEN, GFP_KERNEL);
3880 		if (save)
3881 			memcpy(save, ((char *) es) +
3882 			       EXT4_S_ERR_START, EXT4_S_ERR_LEN);
3883 		err = jbd2_journal_load(journal);
3884 		if (save)
3885 			memcpy(((char *) es) + EXT4_S_ERR_START,
3886 			       save, EXT4_S_ERR_LEN);
3887 		kfree(save);
3888 	}
3889 
3890 	if (err) {
3891 		ext4_msg(sb, KERN_ERR, "error loading journal");
3892 		jbd2_journal_destroy(journal);
3893 		return err;
3894 	}
3895 
3896 	EXT4_SB(sb)->s_journal = journal;
3897 	ext4_clear_journal_err(sb, es);
3898 
3899 	if (!really_read_only && journal_devnum &&
3900 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
3901 		es->s_journal_dev = cpu_to_le32(journal_devnum);
3902 
3903 		/* Make sure we flush the recovery flag to disk. */
3904 		ext4_commit_super(sb, 1);
3905 	}
3906 
3907 	return 0;
3908 }
3909 
3910 static int ext4_commit_super(struct super_block *sb, int sync)
3911 {
3912 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
3913 	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
3914 	int error = 0;
3915 
3916 	if (!sbh)
3917 		return error;
3918 	if (buffer_write_io_error(sbh)) {
3919 		/*
3920 		 * Oh, dear.  A previous attempt to write the
3921 		 * superblock failed.  This could happen because the
3922 		 * USB device was yanked out.  Or it could happen to
3923 		 * be a transient write error and maybe the block will
3924 		 * be remapped.  Nothing we can do but to retry the
3925 		 * write and hope for the best.
3926 		 */
3927 		ext4_msg(sb, KERN_ERR, "previous I/O error to "
3928 		       "superblock detected");
3929 		clear_buffer_write_io_error(sbh);
3930 		set_buffer_uptodate(sbh);
3931 	}
3932 	/*
3933 	 * If the file system is mounted read-only, don't update the
3934 	 * superblock write time.  This avoids updating the superblock
3935 	 * write time when we are mounting the root file system
3936 	 * read/only but we need to replay the journal; at that point,
3937 	 * for people who are east of GMT and who make their clock
3938 	 * tick in localtime for Windows bug-for-bug compatibility,
3939 	 * the clock is set in the future, and this will cause e2fsck
3940 	 * to complain and force a full file system check.
3941 	 */
3942 	if (!(sb->s_flags & MS_RDONLY))
3943 		es->s_wtime = cpu_to_le32(get_seconds());
3944 	if (sb->s_bdev->bd_part)
3945 		es->s_kbytes_written =
3946 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written +
3947 			    ((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
3948 			      EXT4_SB(sb)->s_sectors_written_start) >> 1));
3949 	else
3950 		es->s_kbytes_written =
3951 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written);
3952 	if (percpu_counter_initialized(&EXT4_SB(sb)->s_freeblocks_counter))
3953 		ext4_free_blocks_count_set(es, percpu_counter_sum_positive(
3954 					&EXT4_SB(sb)->s_freeblocks_counter));
3955 	if (percpu_counter_initialized(&EXT4_SB(sb)->s_freeinodes_counter))
3956 		es->s_free_inodes_count =
3957 			cpu_to_le32(percpu_counter_sum_positive(
3958 					&EXT4_SB(sb)->s_freeinodes_counter));
3959 	sb->s_dirt = 0;
3960 	BUFFER_TRACE(sbh, "marking dirty");
3961 	mark_buffer_dirty(sbh);
3962 	if (sync) {
3963 		error = sync_dirty_buffer(sbh);
3964 		if (error)
3965 			return error;
3966 
3967 		error = buffer_write_io_error(sbh);
3968 		if (error) {
3969 			ext4_msg(sb, KERN_ERR, "I/O error while writing "
3970 			       "superblock");
3971 			clear_buffer_write_io_error(sbh);
3972 			set_buffer_uptodate(sbh);
3973 		}
3974 	}
3975 	return error;
3976 }
3977 
3978 /*
3979  * Have we just finished recovery?  If so, and if we are mounting (or
3980  * remounting) the filesystem readonly, then we will end up with a
3981  * consistent fs on disk.  Record that fact.
3982  */
3983 static void ext4_mark_recovery_complete(struct super_block *sb,
3984 					struct ext4_super_block *es)
3985 {
3986 	journal_t *journal = EXT4_SB(sb)->s_journal;
3987 
3988 	if (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
3989 		BUG_ON(journal != NULL);
3990 		return;
3991 	}
3992 	jbd2_journal_lock_updates(journal);
3993 	if (jbd2_journal_flush(journal) < 0)
3994 		goto out;
3995 
3996 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER) &&
3997 	    sb->s_flags & MS_RDONLY) {
3998 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
3999 		ext4_commit_super(sb, 1);
4000 	}
4001 
4002 out:
4003 	jbd2_journal_unlock_updates(journal);
4004 }
4005 
4006 /*
4007  * If we are mounting (or read-write remounting) a filesystem whose journal
4008  * has recorded an error from a previous lifetime, move that error to the
4009  * main filesystem now.
4010  */
4011 static void ext4_clear_journal_err(struct super_block *sb,
4012 				   struct ext4_super_block *es)
4013 {
4014 	journal_t *journal;
4015 	int j_errno;
4016 	const char *errstr;
4017 
4018 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4019 
4020 	journal = EXT4_SB(sb)->s_journal;
4021 
4022 	/*
4023 	 * Now check for any error status which may have been recorded in the
4024 	 * journal by a prior ext4_error() or ext4_abort()
4025 	 */
4026 
4027 	j_errno = jbd2_journal_errno(journal);
4028 	if (j_errno) {
4029 		char nbuf[16];
4030 
4031 		errstr = ext4_decode_error(sb, j_errno, nbuf);
4032 		ext4_warning(sb, "Filesystem error recorded "
4033 			     "from previous mount: %s", errstr);
4034 		ext4_warning(sb, "Marking fs in need of filesystem check.");
4035 
4036 		EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
4037 		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
4038 		ext4_commit_super(sb, 1);
4039 
4040 		jbd2_journal_clear_err(journal);
4041 	}
4042 }
4043 
4044 /*
4045  * Force the running and committing transactions to commit,
4046  * and wait on the commit.
4047  */
4048 int ext4_force_commit(struct super_block *sb)
4049 {
4050 	journal_t *journal;
4051 	int ret = 0;
4052 
4053 	if (sb->s_flags & MS_RDONLY)
4054 		return 0;
4055 
4056 	journal = EXT4_SB(sb)->s_journal;
4057 	if (journal) {
4058 		vfs_check_frozen(sb, SB_FREEZE_TRANS);
4059 		ret = ext4_journal_force_commit(journal);
4060 	}
4061 
4062 	return ret;
4063 }
4064 
4065 static void ext4_write_super(struct super_block *sb)
4066 {
4067 	lock_super(sb);
4068 	ext4_commit_super(sb, 1);
4069 	unlock_super(sb);
4070 }
4071 
4072 static int ext4_sync_fs(struct super_block *sb, int wait)
4073 {
4074 	int ret = 0;
4075 	tid_t target;
4076 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4077 
4078 	trace_ext4_sync_fs(sb, wait);
4079 	flush_workqueue(sbi->dio_unwritten_wq);
4080 	if (jbd2_journal_start_commit(sbi->s_journal, &target)) {
4081 		if (wait)
4082 			jbd2_log_wait_commit(sbi->s_journal, target);
4083 	}
4084 	return ret;
4085 }
4086 
4087 /*
4088  * LVM calls this function before a (read-only) snapshot is created.  This
4089  * gives us a chance to flush the journal completely and mark the fs clean.
4090  */
4091 static int ext4_freeze(struct super_block *sb)
4092 {
4093 	int error = 0;
4094 	journal_t *journal;
4095 
4096 	if (sb->s_flags & MS_RDONLY)
4097 		return 0;
4098 
4099 	journal = EXT4_SB(sb)->s_journal;
4100 
4101 	/* Now we set up the journal barrier. */
4102 	jbd2_journal_lock_updates(journal);
4103 
4104 	/*
4105 	 * Don't clear the needs_recovery flag if we failed to flush
4106 	 * the journal.
4107 	 */
4108 	error = jbd2_journal_flush(journal);
4109 	if (error < 0)
4110 		goto out;
4111 
4112 	/* Journal blocked and flushed, clear needs_recovery flag. */
4113 	EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4114 	error = ext4_commit_super(sb, 1);
4115 out:
4116 	/* we rely on s_frozen to stop further updates */
4117 	jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
4118 	return error;
4119 }
4120 
4121 /*
4122  * Called by LVM after the snapshot is done.  We need to reset the RECOVER
4123  * flag here, even though the filesystem is not technically dirty yet.
4124  */
4125 static int ext4_unfreeze(struct super_block *sb)
4126 {
4127 	if (sb->s_flags & MS_RDONLY)
4128 		return 0;
4129 
4130 	lock_super(sb);
4131 	/* Reset the needs_recovery flag before the fs is unlocked. */
4132 	EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4133 	ext4_commit_super(sb, 1);
4134 	unlock_super(sb);
4135 	return 0;
4136 }
4137 
4138 static int ext4_remount(struct super_block *sb, int *flags, char *data)
4139 {
4140 	struct ext4_super_block *es;
4141 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4142 	ext4_fsblk_t n_blocks_count = 0;
4143 	unsigned long old_sb_flags;
4144 	struct ext4_mount_options old_opts;
4145 	int enable_quota = 0;
4146 	ext4_group_t g;
4147 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
4148 	int err;
4149 #ifdef CONFIG_QUOTA
4150 	int i;
4151 #endif
4152 	char *orig_data = kstrdup(data, GFP_KERNEL);
4153 
4154 	/* Store the original options */
4155 	lock_super(sb);
4156 	old_sb_flags = sb->s_flags;
4157 	old_opts.s_mount_opt = sbi->s_mount_opt;
4158 	old_opts.s_resuid = sbi->s_resuid;
4159 	old_opts.s_resgid = sbi->s_resgid;
4160 	old_opts.s_commit_interval = sbi->s_commit_interval;
4161 	old_opts.s_min_batch_time = sbi->s_min_batch_time;
4162 	old_opts.s_max_batch_time = sbi->s_max_batch_time;
4163 #ifdef CONFIG_QUOTA
4164 	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
4165 	for (i = 0; i < MAXQUOTAS; i++)
4166 		old_opts.s_qf_names[i] = sbi->s_qf_names[i];
4167 #endif
4168 	if (sbi->s_journal && sbi->s_journal->j_task->io_context)
4169 		journal_ioprio = sbi->s_journal->j_task->io_context->ioprio;
4170 
4171 	/*
4172 	 * Allow the "check" option to be passed as a remount option.
4173 	 */
4174 	if (!parse_options(data, sb, NULL, &journal_ioprio,
4175 			   &n_blocks_count, 1)) {
4176 		err = -EINVAL;
4177 		goto restore_opts;
4178 	}
4179 
4180 	if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
4181 		ext4_abort(sb, "Abort forced by user");
4182 
4183 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
4184 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
4185 
4186 	es = sbi->s_es;
4187 
4188 	if (sbi->s_journal) {
4189 		ext4_init_journal_params(sb, sbi->s_journal);
4190 		set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
4191 	}
4192 
4193 	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY) ||
4194 		n_blocks_count > ext4_blocks_count(es)) {
4195 		if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) {
4196 			err = -EROFS;
4197 			goto restore_opts;
4198 		}
4199 
4200 		if (*flags & MS_RDONLY) {
4201 			err = dquot_suspend(sb, -1);
4202 			if (err < 0)
4203 				goto restore_opts;
4204 
4205 			/*
4206 			 * First of all, the unconditional stuff we have to do
4207 			 * to disable replay of the journal when we next remount
4208 			 */
4209 			sb->s_flags |= MS_RDONLY;
4210 
4211 			/*
4212 			 * OK, test if we are remounting a valid rw partition
4213 			 * readonly, and if so set the rdonly flag and then
4214 			 * mark the partition as valid again.
4215 			 */
4216 			if (!(es->s_state & cpu_to_le16(EXT4_VALID_FS)) &&
4217 			    (sbi->s_mount_state & EXT4_VALID_FS))
4218 				es->s_state = cpu_to_le16(sbi->s_mount_state);
4219 
4220 			if (sbi->s_journal)
4221 				ext4_mark_recovery_complete(sb, es);
4222 		} else {
4223 			/* Make sure we can mount this feature set readwrite */
4224 			if (!ext4_feature_set_ok(sb, 0)) {
4225 				err = -EROFS;
4226 				goto restore_opts;
4227 			}
4228 			/*
4229 			 * Make sure the group descriptor checksums
4230 			 * are sane.  If they aren't, refuse to remount r/w.
4231 			 */
4232 			for (g = 0; g < sbi->s_groups_count; g++) {
4233 				struct ext4_group_desc *gdp =
4234 					ext4_get_group_desc(sb, g, NULL);
4235 
4236 				if (!ext4_group_desc_csum_verify(sbi, g, gdp)) {
4237 					ext4_msg(sb, KERN_ERR,
4238 	       "ext4_remount: Checksum for group %u failed (%u!=%u)",
4239 		g, le16_to_cpu(ext4_group_desc_csum(sbi, g, gdp)),
4240 					       le16_to_cpu(gdp->bg_checksum));
4241 					err = -EINVAL;
4242 					goto restore_opts;
4243 				}
4244 			}
4245 
4246 			/*
4247 			 * If we have an unprocessed orphan list hanging
4248 			 * around from a previously readonly bdev mount,
4249 			 * require a full umount/remount for now.
4250 			 */
4251 			if (es->s_last_orphan) {
4252 				ext4_msg(sb, KERN_WARNING, "Couldn't "
4253 				       "remount RDWR because of unprocessed "
4254 				       "orphan inode list.  Please "
4255 				       "umount/remount instead");
4256 				err = -EINVAL;
4257 				goto restore_opts;
4258 			}
4259 
4260 			/*
4261 			 * Mounting a RDONLY partition read-write, so reread
4262 			 * and store the current valid flag.  (It may have
4263 			 * been changed by e2fsck since we originally mounted
4264 			 * the partition.)
4265 			 */
4266 			if (sbi->s_journal)
4267 				ext4_clear_journal_err(sb, es);
4268 			sbi->s_mount_state = le16_to_cpu(es->s_state);
4269 			if ((err = ext4_group_extend(sb, es, n_blocks_count)))
4270 				goto restore_opts;
4271 			if (!ext4_setup_super(sb, es, 0))
4272 				sb->s_flags &= ~MS_RDONLY;
4273 			enable_quota = 1;
4274 		}
4275 	}
4276 
4277 	/*
4278 	 * Reinitialize lazy itable initialization thread based on
4279 	 * current settings
4280 	 */
4281 	if ((sb->s_flags & MS_RDONLY) || !test_opt(sb, INIT_INODE_TABLE))
4282 		ext4_unregister_li_request(sb);
4283 	else {
4284 		ext4_group_t first_not_zeroed;
4285 		first_not_zeroed = ext4_has_uninit_itable(sb);
4286 		ext4_register_li_request(sb, first_not_zeroed);
4287 	}
4288 
4289 	ext4_setup_system_zone(sb);
4290 	if (sbi->s_journal == NULL)
4291 		ext4_commit_super(sb, 1);
4292 
4293 #ifdef CONFIG_QUOTA
4294 	/* Release old quota file names */
4295 	for (i = 0; i < MAXQUOTAS; i++)
4296 		if (old_opts.s_qf_names[i] &&
4297 		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
4298 			kfree(old_opts.s_qf_names[i]);
4299 #endif
4300 	unlock_super(sb);
4301 	if (enable_quota)
4302 		dquot_resume(sb, -1);
4303 
4304 	ext4_msg(sb, KERN_INFO, "re-mounted. Opts: %s", orig_data);
4305 	kfree(orig_data);
4306 	return 0;
4307 
4308 restore_opts:
4309 	sb->s_flags = old_sb_flags;
4310 	sbi->s_mount_opt = old_opts.s_mount_opt;
4311 	sbi->s_resuid = old_opts.s_resuid;
4312 	sbi->s_resgid = old_opts.s_resgid;
4313 	sbi->s_commit_interval = old_opts.s_commit_interval;
4314 	sbi->s_min_batch_time = old_opts.s_min_batch_time;
4315 	sbi->s_max_batch_time = old_opts.s_max_batch_time;
4316 #ifdef CONFIG_QUOTA
4317 	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
4318 	for (i = 0; i < MAXQUOTAS; i++) {
4319 		if (sbi->s_qf_names[i] &&
4320 		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
4321 			kfree(sbi->s_qf_names[i]);
4322 		sbi->s_qf_names[i] = old_opts.s_qf_names[i];
4323 	}
4324 #endif
4325 	unlock_super(sb);
4326 	kfree(orig_data);
4327 	return err;
4328 }
4329 
4330 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
4331 {
4332 	struct super_block *sb = dentry->d_sb;
4333 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4334 	struct ext4_super_block *es = sbi->s_es;
4335 	u64 fsid;
4336 
4337 	if (test_opt(sb, MINIX_DF)) {
4338 		sbi->s_overhead_last = 0;
4339 	} else if (sbi->s_blocks_last != ext4_blocks_count(es)) {
4340 		ext4_group_t i, ngroups = ext4_get_groups_count(sb);
4341 		ext4_fsblk_t overhead = 0;
4342 
4343 		/*
4344 		 * Compute the overhead (FS structures).  This is constant
4345 		 * for a given filesystem unless the number of block groups
4346 		 * changes so we cache the previous value until it does.
4347 		 */
4348 
4349 		/*
4350 		 * All of the blocks before first_data_block are
4351 		 * overhead
4352 		 */
4353 		overhead = le32_to_cpu(es->s_first_data_block);
4354 
4355 		/*
4356 		 * Add the overhead attributed to the superblock and
4357 		 * block group descriptors.  If the sparse superblocks
4358 		 * feature is turned on, then not all groups have this.
4359 		 */
4360 		for (i = 0; i < ngroups; i++) {
4361 			overhead += ext4_bg_has_super(sb, i) +
4362 				ext4_bg_num_gdb(sb, i);
4363 			cond_resched();
4364 		}
4365 
4366 		/*
4367 		 * Every block group has an inode bitmap, a block
4368 		 * bitmap, and an inode table.
4369 		 */
4370 		overhead += ngroups * (2 + sbi->s_itb_per_group);
4371 		sbi->s_overhead_last = overhead;
4372 		smp_wmb();
4373 		sbi->s_blocks_last = ext4_blocks_count(es);
4374 	}
4375 
4376 	buf->f_type = EXT4_SUPER_MAGIC;
4377 	buf->f_bsize = sb->s_blocksize;
4378 	buf->f_blocks = ext4_blocks_count(es) - sbi->s_overhead_last;
4379 	buf->f_bfree = percpu_counter_sum_positive(&sbi->s_freeblocks_counter) -
4380 		       percpu_counter_sum_positive(&sbi->s_dirtyblocks_counter);
4381 	buf->f_bavail = buf->f_bfree - ext4_r_blocks_count(es);
4382 	if (buf->f_bfree < ext4_r_blocks_count(es))
4383 		buf->f_bavail = 0;
4384 	buf->f_files = le32_to_cpu(es->s_inodes_count);
4385 	buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter);
4386 	buf->f_namelen = EXT4_NAME_LEN;
4387 	fsid = le64_to_cpup((void *)es->s_uuid) ^
4388 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
4389 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
4390 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
4391 
4392 	return 0;
4393 }
4394 
4395 /* Helper function for writing quotas on sync - we need to start transaction
4396  * before quota file is locked for write. Otherwise the are possible deadlocks:
4397  * Process 1                         Process 2
4398  * ext4_create()                     quota_sync()
4399  *   jbd2_journal_start()                  write_dquot()
4400  *   dquot_initialize()                         down(dqio_mutex)
4401  *     down(dqio_mutex)                    jbd2_journal_start()
4402  *
4403  */
4404 
4405 #ifdef CONFIG_QUOTA
4406 
4407 static inline struct inode *dquot_to_inode(struct dquot *dquot)
4408 {
4409 	return sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
4410 }
4411 
4412 static int ext4_write_dquot(struct dquot *dquot)
4413 {
4414 	int ret, err;
4415 	handle_t *handle;
4416 	struct inode *inode;
4417 
4418 	inode = dquot_to_inode(dquot);
4419 	handle = ext4_journal_start(inode,
4420 				    EXT4_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
4421 	if (IS_ERR(handle))
4422 		return PTR_ERR(handle);
4423 	ret = dquot_commit(dquot);
4424 	err = ext4_journal_stop(handle);
4425 	if (!ret)
4426 		ret = err;
4427 	return ret;
4428 }
4429 
4430 static int ext4_acquire_dquot(struct dquot *dquot)
4431 {
4432 	int ret, err;
4433 	handle_t *handle;
4434 
4435 	handle = ext4_journal_start(dquot_to_inode(dquot),
4436 				    EXT4_QUOTA_INIT_BLOCKS(dquot->dq_sb));
4437 	if (IS_ERR(handle))
4438 		return PTR_ERR(handle);
4439 	ret = dquot_acquire(dquot);
4440 	err = ext4_journal_stop(handle);
4441 	if (!ret)
4442 		ret = err;
4443 	return ret;
4444 }
4445 
4446 static int ext4_release_dquot(struct dquot *dquot)
4447 {
4448 	int ret, err;
4449 	handle_t *handle;
4450 
4451 	handle = ext4_journal_start(dquot_to_inode(dquot),
4452 				    EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
4453 	if (IS_ERR(handle)) {
4454 		/* Release dquot anyway to avoid endless cycle in dqput() */
4455 		dquot_release(dquot);
4456 		return PTR_ERR(handle);
4457 	}
4458 	ret = dquot_release(dquot);
4459 	err = ext4_journal_stop(handle);
4460 	if (!ret)
4461 		ret = err;
4462 	return ret;
4463 }
4464 
4465 static int ext4_mark_dquot_dirty(struct dquot *dquot)
4466 {
4467 	/* Are we journaling quotas? */
4468 	if (EXT4_SB(dquot->dq_sb)->s_qf_names[USRQUOTA] ||
4469 	    EXT4_SB(dquot->dq_sb)->s_qf_names[GRPQUOTA]) {
4470 		dquot_mark_dquot_dirty(dquot);
4471 		return ext4_write_dquot(dquot);
4472 	} else {
4473 		return dquot_mark_dquot_dirty(dquot);
4474 	}
4475 }
4476 
4477 static int ext4_write_info(struct super_block *sb, int type)
4478 {
4479 	int ret, err;
4480 	handle_t *handle;
4481 
4482 	/* Data block + inode block */
4483 	handle = ext4_journal_start(sb->s_root->d_inode, 2);
4484 	if (IS_ERR(handle))
4485 		return PTR_ERR(handle);
4486 	ret = dquot_commit_info(sb, type);
4487 	err = ext4_journal_stop(handle);
4488 	if (!ret)
4489 		ret = err;
4490 	return ret;
4491 }
4492 
4493 /*
4494  * Turn on quotas during mount time - we need to find
4495  * the quota file and such...
4496  */
4497 static int ext4_quota_on_mount(struct super_block *sb, int type)
4498 {
4499 	return dquot_quota_on_mount(sb, EXT4_SB(sb)->s_qf_names[type],
4500 					EXT4_SB(sb)->s_jquota_fmt, type);
4501 }
4502 
4503 /*
4504  * Standard function to be called on quota_on
4505  */
4506 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
4507 			 char *name)
4508 {
4509 	int err;
4510 	struct path path;
4511 
4512 	if (!test_opt(sb, QUOTA))
4513 		return -EINVAL;
4514 
4515 	err = kern_path(name, LOOKUP_FOLLOW, &path);
4516 	if (err)
4517 		return err;
4518 
4519 	/* Quotafile not on the same filesystem? */
4520 	if (path.mnt->mnt_sb != sb) {
4521 		path_put(&path);
4522 		return -EXDEV;
4523 	}
4524 	/* Journaling quota? */
4525 	if (EXT4_SB(sb)->s_qf_names[type]) {
4526 		/* Quotafile not in fs root? */
4527 		if (path.dentry->d_parent != sb->s_root)
4528 			ext4_msg(sb, KERN_WARNING,
4529 				"Quota file not on filesystem root. "
4530 				"Journaled quota will not work");
4531 	}
4532 
4533 	/*
4534 	 * When we journal data on quota file, we have to flush journal to see
4535 	 * all updates to the file when we bypass pagecache...
4536 	 */
4537 	if (EXT4_SB(sb)->s_journal &&
4538 	    ext4_should_journal_data(path.dentry->d_inode)) {
4539 		/*
4540 		 * We don't need to lock updates but journal_flush() could
4541 		 * otherwise be livelocked...
4542 		 */
4543 		jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
4544 		err = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
4545 		jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
4546 		if (err) {
4547 			path_put(&path);
4548 			return err;
4549 		}
4550 	}
4551 
4552 	err = dquot_quota_on_path(sb, type, format_id, &path);
4553 	path_put(&path);
4554 	return err;
4555 }
4556 
4557 static int ext4_quota_off(struct super_block *sb, int type)
4558 {
4559 	/* Force all delayed allocation blocks to be allocated */
4560 	if (test_opt(sb, DELALLOC)) {
4561 		down_read(&sb->s_umount);
4562 		sync_filesystem(sb);
4563 		up_read(&sb->s_umount);
4564 	}
4565 
4566 	return dquot_quota_off(sb, type);
4567 }
4568 
4569 /* Read data from quotafile - avoid pagecache and such because we cannot afford
4570  * acquiring the locks... As quota files are never truncated and quota code
4571  * itself serializes the operations (and noone else should touch the files)
4572  * we don't have to be afraid of races */
4573 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
4574 			       size_t len, loff_t off)
4575 {
4576 	struct inode *inode = sb_dqopt(sb)->files[type];
4577 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
4578 	int err = 0;
4579 	int offset = off & (sb->s_blocksize - 1);
4580 	int tocopy;
4581 	size_t toread;
4582 	struct buffer_head *bh;
4583 	loff_t i_size = i_size_read(inode);
4584 
4585 	if (off > i_size)
4586 		return 0;
4587 	if (off+len > i_size)
4588 		len = i_size-off;
4589 	toread = len;
4590 	while (toread > 0) {
4591 		tocopy = sb->s_blocksize - offset < toread ?
4592 				sb->s_blocksize - offset : toread;
4593 		bh = ext4_bread(NULL, inode, blk, 0, &err);
4594 		if (err)
4595 			return err;
4596 		if (!bh)	/* A hole? */
4597 			memset(data, 0, tocopy);
4598 		else
4599 			memcpy(data, bh->b_data+offset, tocopy);
4600 		brelse(bh);
4601 		offset = 0;
4602 		toread -= tocopy;
4603 		data += tocopy;
4604 		blk++;
4605 	}
4606 	return len;
4607 }
4608 
4609 /* Write to quotafile (we know the transaction is already started and has
4610  * enough credits) */
4611 static ssize_t ext4_quota_write(struct super_block *sb, int type,
4612 				const char *data, size_t len, loff_t off)
4613 {
4614 	struct inode *inode = sb_dqopt(sb)->files[type];
4615 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
4616 	int err = 0;
4617 	int offset = off & (sb->s_blocksize - 1);
4618 	struct buffer_head *bh;
4619 	handle_t *handle = journal_current_handle();
4620 
4621 	if (EXT4_SB(sb)->s_journal && !handle) {
4622 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
4623 			" cancelled because transaction is not started",
4624 			(unsigned long long)off, (unsigned long long)len);
4625 		return -EIO;
4626 	}
4627 	/*
4628 	 * Since we account only one data block in transaction credits,
4629 	 * then it is impossible to cross a block boundary.
4630 	 */
4631 	if (sb->s_blocksize - offset < len) {
4632 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
4633 			" cancelled because not block aligned",
4634 			(unsigned long long)off, (unsigned long long)len);
4635 		return -EIO;
4636 	}
4637 
4638 	mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
4639 	bh = ext4_bread(handle, inode, blk, 1, &err);
4640 	if (!bh)
4641 		goto out;
4642 	err = ext4_journal_get_write_access(handle, bh);
4643 	if (err) {
4644 		brelse(bh);
4645 		goto out;
4646 	}
4647 	lock_buffer(bh);
4648 	memcpy(bh->b_data+offset, data, len);
4649 	flush_dcache_page(bh->b_page);
4650 	unlock_buffer(bh);
4651 	err = ext4_handle_dirty_metadata(handle, NULL, bh);
4652 	brelse(bh);
4653 out:
4654 	if (err) {
4655 		mutex_unlock(&inode->i_mutex);
4656 		return err;
4657 	}
4658 	if (inode->i_size < off + len) {
4659 		i_size_write(inode, off + len);
4660 		EXT4_I(inode)->i_disksize = inode->i_size;
4661 	}
4662 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
4663 	ext4_mark_inode_dirty(handle, inode);
4664 	mutex_unlock(&inode->i_mutex);
4665 	return len;
4666 }
4667 
4668 #endif
4669 
4670 static int ext4_get_sb(struct file_system_type *fs_type, int flags,
4671 		       const char *dev_name, void *data, struct vfsmount *mnt)
4672 {
4673 	return get_sb_bdev(fs_type, flags, dev_name, data, ext4_fill_super,mnt);
4674 }
4675 
4676 #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
4677 static struct file_system_type ext2_fs_type = {
4678 	.owner		= THIS_MODULE,
4679 	.name		= "ext2",
4680 	.get_sb		= ext4_get_sb,
4681 	.kill_sb	= kill_block_super,
4682 	.fs_flags	= FS_REQUIRES_DEV,
4683 };
4684 
4685 static inline void register_as_ext2(void)
4686 {
4687 	int err = register_filesystem(&ext2_fs_type);
4688 	if (err)
4689 		printk(KERN_WARNING
4690 		       "EXT4-fs: Unable to register as ext2 (%d)\n", err);
4691 }
4692 
4693 static inline void unregister_as_ext2(void)
4694 {
4695 	unregister_filesystem(&ext2_fs_type);
4696 }
4697 MODULE_ALIAS("ext2");
4698 #else
4699 static inline void register_as_ext2(void) { }
4700 static inline void unregister_as_ext2(void) { }
4701 #endif
4702 
4703 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
4704 static inline void register_as_ext3(void)
4705 {
4706 	int err = register_filesystem(&ext3_fs_type);
4707 	if (err)
4708 		printk(KERN_WARNING
4709 		       "EXT4-fs: Unable to register as ext3 (%d)\n", err);
4710 }
4711 
4712 static inline void unregister_as_ext3(void)
4713 {
4714 	unregister_filesystem(&ext3_fs_type);
4715 }
4716 MODULE_ALIAS("ext3");
4717 #else
4718 static inline void register_as_ext3(void) { }
4719 static inline void unregister_as_ext3(void) { }
4720 #endif
4721 
4722 static struct file_system_type ext4_fs_type = {
4723 	.owner		= THIS_MODULE,
4724 	.name		= "ext4",
4725 	.get_sb		= ext4_get_sb,
4726 	.kill_sb	= kill_block_super,
4727 	.fs_flags	= FS_REQUIRES_DEV,
4728 };
4729 
4730 int __init ext4_init_feat_adverts(void)
4731 {
4732 	struct ext4_features *ef;
4733 	int ret = -ENOMEM;
4734 
4735 	ef = kzalloc(sizeof(struct ext4_features), GFP_KERNEL);
4736 	if (!ef)
4737 		goto out;
4738 
4739 	ef->f_kobj.kset = ext4_kset;
4740 	init_completion(&ef->f_kobj_unregister);
4741 	ret = kobject_init_and_add(&ef->f_kobj, &ext4_feat_ktype, NULL,
4742 				   "features");
4743 	if (ret) {
4744 		kfree(ef);
4745 		goto out;
4746 	}
4747 
4748 	ext4_feat = ef;
4749 	ret = 0;
4750 out:
4751 	return ret;
4752 }
4753 
4754 static int __init ext4_init_fs(void)
4755 {
4756 	int err;
4757 
4758 	ext4_check_flag_values();
4759 	err = ext4_init_pageio();
4760 	if (err)
4761 		return err;
4762 	err = ext4_init_system_zone();
4763 	if (err)
4764 		goto out5;
4765 	ext4_kset = kset_create_and_add("ext4", NULL, fs_kobj);
4766 	if (!ext4_kset)
4767 		goto out4;
4768 	ext4_proc_root = proc_mkdir("fs/ext4", NULL);
4769 
4770 	err = ext4_init_feat_adverts();
4771 
4772 	err = ext4_init_mballoc();
4773 	if (err)
4774 		goto out3;
4775 
4776 	err = ext4_init_xattr();
4777 	if (err)
4778 		goto out2;
4779 	err = init_inodecache();
4780 	if (err)
4781 		goto out1;
4782 	register_as_ext2();
4783 	register_as_ext3();
4784 	err = register_filesystem(&ext4_fs_type);
4785 	if (err)
4786 		goto out;
4787 
4788 	ext4_li_info = NULL;
4789 	mutex_init(&ext4_li_mtx);
4790 	return 0;
4791 out:
4792 	unregister_as_ext2();
4793 	unregister_as_ext3();
4794 	destroy_inodecache();
4795 out1:
4796 	ext4_exit_xattr();
4797 out2:
4798 	ext4_exit_mballoc();
4799 out3:
4800 	kfree(ext4_feat);
4801 	remove_proc_entry("fs/ext4", NULL);
4802 	kset_unregister(ext4_kset);
4803 out4:
4804 	ext4_exit_system_zone();
4805 out5:
4806 	ext4_exit_pageio();
4807 	return err;
4808 }
4809 
4810 static void __exit ext4_exit_fs(void)
4811 {
4812 	ext4_destroy_lazyinit_thread();
4813 	unregister_as_ext2();
4814 	unregister_as_ext3();
4815 	unregister_filesystem(&ext4_fs_type);
4816 	destroy_inodecache();
4817 	ext4_exit_xattr();
4818 	ext4_exit_mballoc();
4819 	remove_proc_entry("fs/ext4", NULL);
4820 	kset_unregister(ext4_kset);
4821 	ext4_exit_system_zone();
4822 	ext4_exit_pageio();
4823 }
4824 
4825 MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
4826 MODULE_DESCRIPTION("Fourth Extended Filesystem");
4827 MODULE_LICENSE("GPL");
4828 module_init(ext4_init_fs)
4829 module_exit(ext4_exit_fs)
4830