xref: /linux/fs/ext4/super.c (revision a33f32244d8550da8b4a26e277ce07d5c6d158b5)
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/smp_lock.h>
30 #include <linux/buffer_head.h>
31 #include <linux/exportfs.h>
32 #include <linux/vfs.h>
33 #include <linux/random.h>
34 #include <linux/mount.h>
35 #include <linux/namei.h>
36 #include <linux/quotaops.h>
37 #include <linux/seq_file.h>
38 #include <linux/proc_fs.h>
39 #include <linux/ctype.h>
40 #include <linux/log2.h>
41 #include <linux/crc16.h>
42 #include <asm/uaccess.h>
43 
44 #include "ext4.h"
45 #include "ext4_jbd2.h"
46 #include "xattr.h"
47 #include "acl.h"
48 #include "mballoc.h"
49 
50 #define CREATE_TRACE_POINTS
51 #include <trace/events/ext4.h>
52 
53 struct proc_dir_entry *ext4_proc_root;
54 static struct kset *ext4_kset;
55 
56 static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
57 			     unsigned long journal_devnum);
58 static int ext4_commit_super(struct super_block *sb, int sync);
59 static void ext4_mark_recovery_complete(struct super_block *sb,
60 					struct ext4_super_block *es);
61 static void ext4_clear_journal_err(struct super_block *sb,
62 				   struct ext4_super_block *es);
63 static int ext4_sync_fs(struct super_block *sb, int wait);
64 static const char *ext4_decode_error(struct super_block *sb, int errno,
65 				     char nbuf[16]);
66 static int ext4_remount(struct super_block *sb, int *flags, char *data);
67 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf);
68 static int ext4_unfreeze(struct super_block *sb);
69 static void ext4_write_super(struct super_block *sb);
70 static int ext4_freeze(struct super_block *sb);
71 static int ext4_get_sb(struct file_system_type *fs_type, int flags,
72 		       const char *dev_name, void *data, struct vfsmount *mnt);
73 
74 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
75 static struct file_system_type ext3_fs_type = {
76 	.owner		= THIS_MODULE,
77 	.name		= "ext3",
78 	.get_sb		= ext4_get_sb,
79 	.kill_sb	= kill_block_super,
80 	.fs_flags	= FS_REQUIRES_DEV,
81 };
82 #define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type)
83 #else
84 #define IS_EXT3_SB(sb) (0)
85 #endif
86 
87 ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
88 			       struct ext4_group_desc *bg)
89 {
90 	return le32_to_cpu(bg->bg_block_bitmap_lo) |
91 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
92 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_block_bitmap_hi) << 32 : 0);
93 }
94 
95 ext4_fsblk_t ext4_inode_bitmap(struct super_block *sb,
96 			       struct ext4_group_desc *bg)
97 {
98 	return le32_to_cpu(bg->bg_inode_bitmap_lo) |
99 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
100 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_bitmap_hi) << 32 : 0);
101 }
102 
103 ext4_fsblk_t ext4_inode_table(struct super_block *sb,
104 			      struct ext4_group_desc *bg)
105 {
106 	return le32_to_cpu(bg->bg_inode_table_lo) |
107 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
108 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_table_hi) << 32 : 0);
109 }
110 
111 __u32 ext4_free_blks_count(struct super_block *sb,
112 			      struct ext4_group_desc *bg)
113 {
114 	return le16_to_cpu(bg->bg_free_blocks_count_lo) |
115 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
116 		 (__u32)le16_to_cpu(bg->bg_free_blocks_count_hi) << 16 : 0);
117 }
118 
119 __u32 ext4_free_inodes_count(struct super_block *sb,
120 			      struct ext4_group_desc *bg)
121 {
122 	return le16_to_cpu(bg->bg_free_inodes_count_lo) |
123 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
124 		 (__u32)le16_to_cpu(bg->bg_free_inodes_count_hi) << 16 : 0);
125 }
126 
127 __u32 ext4_used_dirs_count(struct super_block *sb,
128 			      struct ext4_group_desc *bg)
129 {
130 	return le16_to_cpu(bg->bg_used_dirs_count_lo) |
131 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
132 		 (__u32)le16_to_cpu(bg->bg_used_dirs_count_hi) << 16 : 0);
133 }
134 
135 __u32 ext4_itable_unused_count(struct super_block *sb,
136 			      struct ext4_group_desc *bg)
137 {
138 	return le16_to_cpu(bg->bg_itable_unused_lo) |
139 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
140 		 (__u32)le16_to_cpu(bg->bg_itable_unused_hi) << 16 : 0);
141 }
142 
143 void ext4_block_bitmap_set(struct super_block *sb,
144 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
145 {
146 	bg->bg_block_bitmap_lo = cpu_to_le32((u32)blk);
147 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
148 		bg->bg_block_bitmap_hi = cpu_to_le32(blk >> 32);
149 }
150 
151 void ext4_inode_bitmap_set(struct super_block *sb,
152 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
153 {
154 	bg->bg_inode_bitmap_lo  = cpu_to_le32((u32)blk);
155 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
156 		bg->bg_inode_bitmap_hi = cpu_to_le32(blk >> 32);
157 }
158 
159 void ext4_inode_table_set(struct super_block *sb,
160 			  struct ext4_group_desc *bg, ext4_fsblk_t blk)
161 {
162 	bg->bg_inode_table_lo = cpu_to_le32((u32)blk);
163 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
164 		bg->bg_inode_table_hi = cpu_to_le32(blk >> 32);
165 }
166 
167 void ext4_free_blks_set(struct super_block *sb,
168 			  struct ext4_group_desc *bg, __u32 count)
169 {
170 	bg->bg_free_blocks_count_lo = cpu_to_le16((__u16)count);
171 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
172 		bg->bg_free_blocks_count_hi = cpu_to_le16(count >> 16);
173 }
174 
175 void ext4_free_inodes_set(struct super_block *sb,
176 			  struct ext4_group_desc *bg, __u32 count)
177 {
178 	bg->bg_free_inodes_count_lo = cpu_to_le16((__u16)count);
179 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
180 		bg->bg_free_inodes_count_hi = cpu_to_le16(count >> 16);
181 }
182 
183 void ext4_used_dirs_set(struct super_block *sb,
184 			  struct ext4_group_desc *bg, __u32 count)
185 {
186 	bg->bg_used_dirs_count_lo = cpu_to_le16((__u16)count);
187 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
188 		bg->bg_used_dirs_count_hi = cpu_to_le16(count >> 16);
189 }
190 
191 void ext4_itable_unused_set(struct super_block *sb,
192 			  struct ext4_group_desc *bg, __u32 count)
193 {
194 	bg->bg_itable_unused_lo = cpu_to_le16((__u16)count);
195 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
196 		bg->bg_itable_unused_hi = cpu_to_le16(count >> 16);
197 }
198 
199 
200 /* Just increment the non-pointer handle value */
201 static handle_t *ext4_get_nojournal(void)
202 {
203 	handle_t *handle = current->journal_info;
204 	unsigned long ref_cnt = (unsigned long)handle;
205 
206 	BUG_ON(ref_cnt >= EXT4_NOJOURNAL_MAX_REF_COUNT);
207 
208 	ref_cnt++;
209 	handle = (handle_t *)ref_cnt;
210 
211 	current->journal_info = handle;
212 	return handle;
213 }
214 
215 
216 /* Decrement the non-pointer handle value */
217 static void ext4_put_nojournal(handle_t *handle)
218 {
219 	unsigned long ref_cnt = (unsigned long)handle;
220 
221 	BUG_ON(ref_cnt == 0);
222 
223 	ref_cnt--;
224 	handle = (handle_t *)ref_cnt;
225 
226 	current->journal_info = handle;
227 }
228 
229 /*
230  * Wrappers for jbd2_journal_start/end.
231  *
232  * The only special thing we need to do here is to make sure that all
233  * journal_end calls result in the superblock being marked dirty, so
234  * that sync() will call the filesystem's write_super callback if
235  * appropriate.
236  */
237 handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
238 {
239 	journal_t *journal;
240 
241 	if (sb->s_flags & MS_RDONLY)
242 		return ERR_PTR(-EROFS);
243 
244 	/* Special case here: if the journal has aborted behind our
245 	 * backs (eg. EIO in the commit thread), then we still need to
246 	 * take the FS itself readonly cleanly. */
247 	journal = EXT4_SB(sb)->s_journal;
248 	if (journal) {
249 		if (is_journal_aborted(journal)) {
250 			ext4_abort(sb, __func__, "Detected aborted journal");
251 			return ERR_PTR(-EROFS);
252 		}
253 		return jbd2_journal_start(journal, nblocks);
254 	}
255 	return ext4_get_nojournal();
256 }
257 
258 /*
259  * The only special thing we need to do here is to make sure that all
260  * jbd2_journal_stop calls result in the superblock being marked dirty, so
261  * that sync() will call the filesystem's write_super callback if
262  * appropriate.
263  */
264 int __ext4_journal_stop(const char *where, handle_t *handle)
265 {
266 	struct super_block *sb;
267 	int err;
268 	int rc;
269 
270 	if (!ext4_handle_valid(handle)) {
271 		ext4_put_nojournal(handle);
272 		return 0;
273 	}
274 	sb = handle->h_transaction->t_journal->j_private;
275 	err = handle->h_err;
276 	rc = jbd2_journal_stop(handle);
277 
278 	if (!err)
279 		err = rc;
280 	if (err)
281 		__ext4_std_error(sb, where, err);
282 	return err;
283 }
284 
285 void ext4_journal_abort_handle(const char *caller, const char *err_fn,
286 		struct buffer_head *bh, handle_t *handle, int err)
287 {
288 	char nbuf[16];
289 	const char *errstr = ext4_decode_error(NULL, err, nbuf);
290 
291 	BUG_ON(!ext4_handle_valid(handle));
292 
293 	if (bh)
294 		BUFFER_TRACE(bh, "abort");
295 
296 	if (!handle->h_err)
297 		handle->h_err = err;
298 
299 	if (is_handle_aborted(handle))
300 		return;
301 
302 	printk(KERN_ERR "%s: aborting transaction: %s in %s\n",
303 	       caller, errstr, err_fn);
304 
305 	jbd2_journal_abort_handle(handle);
306 }
307 
308 /* Deal with the reporting of failure conditions on a filesystem such as
309  * inconsistencies detected or read IO failures.
310  *
311  * On ext2, we can store the error state of the filesystem in the
312  * superblock.  That is not possible on ext4, because we may have other
313  * write ordering constraints on the superblock which prevent us from
314  * writing it out straight away; and given that the journal is about to
315  * be aborted, we can't rely on the current, or future, transactions to
316  * write out the superblock safely.
317  *
318  * We'll just use the jbd2_journal_abort() error code to record an error in
319  * the journal instead.  On recovery, the journal will complain about
320  * that error until we've noted it down and cleared it.
321  */
322 
323 static void ext4_handle_error(struct super_block *sb)
324 {
325 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
326 
327 	EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
328 	es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
329 
330 	if (sb->s_flags & MS_RDONLY)
331 		return;
332 
333 	if (!test_opt(sb, ERRORS_CONT)) {
334 		journal_t *journal = EXT4_SB(sb)->s_journal;
335 
336 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
337 		if (journal)
338 			jbd2_journal_abort(journal, -EIO);
339 	}
340 	if (test_opt(sb, ERRORS_RO)) {
341 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
342 		sb->s_flags |= MS_RDONLY;
343 	}
344 	ext4_commit_super(sb, 1);
345 	if (test_opt(sb, ERRORS_PANIC))
346 		panic("EXT4-fs (device %s): panic forced after error\n",
347 			sb->s_id);
348 }
349 
350 void __ext4_error(struct super_block *sb, const char *function,
351 		const char *fmt, ...)
352 {
353 	va_list args;
354 
355 	va_start(args, fmt);
356 	printk(KERN_CRIT "EXT4-fs error (device %s): %s: ", sb->s_id, function);
357 	vprintk(fmt, args);
358 	printk("\n");
359 	va_end(args);
360 
361 	ext4_handle_error(sb);
362 }
363 
364 void ext4_error_inode(const char *function, struct inode *inode,
365 		      const char *fmt, ...)
366 {
367 	va_list args;
368 
369 	va_start(args, fmt);
370 	printk(KERN_CRIT "EXT4-fs error (device %s): %s: inode #%lu: (comm %s) ",
371 	       inode->i_sb->s_id, function, inode->i_ino, current->comm);
372 	vprintk(fmt, args);
373 	printk("\n");
374 	va_end(args);
375 
376 	ext4_handle_error(inode->i_sb);
377 }
378 
379 void ext4_error_file(const char *function, struct file *file,
380 		     const char *fmt, ...)
381 {
382 	va_list args;
383 	struct inode *inode = file->f_dentry->d_inode;
384 	char pathname[80], *path;
385 
386 	va_start(args, fmt);
387 	path = d_path(&(file->f_path), pathname, sizeof(pathname));
388 	if (!path)
389 		path = "(unknown)";
390 	printk(KERN_CRIT
391 	       "EXT4-fs error (device %s): %s: inode #%lu (comm %s path %s): ",
392 	       inode->i_sb->s_id, function, inode->i_ino, current->comm, path);
393 	vprintk(fmt, args);
394 	printk("\n");
395 	va_end(args);
396 
397 	ext4_handle_error(inode->i_sb);
398 }
399 
400 static const char *ext4_decode_error(struct super_block *sb, int errno,
401 				     char nbuf[16])
402 {
403 	char *errstr = NULL;
404 
405 	switch (errno) {
406 	case -EIO:
407 		errstr = "IO failure";
408 		break;
409 	case -ENOMEM:
410 		errstr = "Out of memory";
411 		break;
412 	case -EROFS:
413 		if (!sb || (EXT4_SB(sb)->s_journal &&
414 			    EXT4_SB(sb)->s_journal->j_flags & JBD2_ABORT))
415 			errstr = "Journal has aborted";
416 		else
417 			errstr = "Readonly filesystem";
418 		break;
419 	default:
420 		/* If the caller passed in an extra buffer for unknown
421 		 * errors, textualise them now.  Else we just return
422 		 * NULL. */
423 		if (nbuf) {
424 			/* Check for truncated error codes... */
425 			if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
426 				errstr = nbuf;
427 		}
428 		break;
429 	}
430 
431 	return errstr;
432 }
433 
434 /* __ext4_std_error decodes expected errors from journaling functions
435  * automatically and invokes the appropriate error response.  */
436 
437 void __ext4_std_error(struct super_block *sb, const char *function, int errno)
438 {
439 	char nbuf[16];
440 	const char *errstr;
441 
442 	/* Special case: if the error is EROFS, and we're not already
443 	 * inside a transaction, then there's really no point in logging
444 	 * an error. */
445 	if (errno == -EROFS && journal_current_handle() == NULL &&
446 	    (sb->s_flags & MS_RDONLY))
447 		return;
448 
449 	errstr = ext4_decode_error(sb, errno, nbuf);
450 	printk(KERN_CRIT "EXT4-fs error (device %s) in %s: %s\n",
451 	       sb->s_id, function, errstr);
452 
453 	ext4_handle_error(sb);
454 }
455 
456 /*
457  * ext4_abort is a much stronger failure handler than ext4_error.  The
458  * abort function may be used to deal with unrecoverable failures such
459  * as journal IO errors or ENOMEM at a critical moment in log management.
460  *
461  * We unconditionally force the filesystem into an ABORT|READONLY state,
462  * unless the error response on the fs has been set to panic in which
463  * case we take the easy way out and panic immediately.
464  */
465 
466 void ext4_abort(struct super_block *sb, const char *function,
467 		const char *fmt, ...)
468 {
469 	va_list args;
470 
471 	va_start(args, fmt);
472 	printk(KERN_CRIT "EXT4-fs error (device %s): %s: ", sb->s_id, function);
473 	vprintk(fmt, args);
474 	printk("\n");
475 	va_end(args);
476 
477 	if (test_opt(sb, ERRORS_PANIC))
478 		panic("EXT4-fs panic from previous error\n");
479 
480 	if (sb->s_flags & MS_RDONLY)
481 		return;
482 
483 	ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
484 	EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
485 	sb->s_flags |= MS_RDONLY;
486 	EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
487 	if (EXT4_SB(sb)->s_journal)
488 		jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
489 }
490 
491 void ext4_msg (struct super_block * sb, const char *prefix,
492 		   const char *fmt, ...)
493 {
494 	va_list args;
495 
496 	va_start(args, fmt);
497 	printk("%sEXT4-fs (%s): ", prefix, sb->s_id);
498 	vprintk(fmt, args);
499 	printk("\n");
500 	va_end(args);
501 }
502 
503 void __ext4_warning(struct super_block *sb, const char *function,
504 		  const char *fmt, ...)
505 {
506 	va_list args;
507 
508 	va_start(args, fmt);
509 	printk(KERN_WARNING "EXT4-fs warning (device %s): %s: ",
510 	       sb->s_id, function);
511 	vprintk(fmt, args);
512 	printk("\n");
513 	va_end(args);
514 }
515 
516 void ext4_grp_locked_error(struct super_block *sb, ext4_group_t grp,
517 			   const char *function, const char *fmt, ...)
518 __releases(bitlock)
519 __acquires(bitlock)
520 {
521 	va_list args;
522 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
523 
524 	va_start(args, fmt);
525 	printk(KERN_CRIT "EXT4-fs error (device %s): %s: ", sb->s_id, function);
526 	vprintk(fmt, args);
527 	printk("\n");
528 	va_end(args);
529 
530 	if (test_opt(sb, ERRORS_CONT)) {
531 		EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
532 		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
533 		ext4_commit_super(sb, 0);
534 		return;
535 	}
536 	ext4_unlock_group(sb, grp);
537 	ext4_handle_error(sb);
538 	/*
539 	 * We only get here in the ERRORS_RO case; relocking the group
540 	 * may be dangerous, but nothing bad will happen since the
541 	 * filesystem will have already been marked read/only and the
542 	 * journal has been aborted.  We return 1 as a hint to callers
543 	 * who might what to use the return value from
544 	 * ext4_grp_locked_error() to distinguish beween the
545 	 * ERRORS_CONT and ERRORS_RO case, and perhaps return more
546 	 * aggressively from the ext4 function in question, with a
547 	 * more appropriate error code.
548 	 */
549 	ext4_lock_group(sb, grp);
550 	return;
551 }
552 
553 void ext4_update_dynamic_rev(struct super_block *sb)
554 {
555 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
556 
557 	if (le32_to_cpu(es->s_rev_level) > EXT4_GOOD_OLD_REV)
558 		return;
559 
560 	ext4_warning(sb,
561 		     "updating to rev %d because of new feature flag, "
562 		     "running e2fsck is recommended",
563 		     EXT4_DYNAMIC_REV);
564 
565 	es->s_first_ino = cpu_to_le32(EXT4_GOOD_OLD_FIRST_INO);
566 	es->s_inode_size = cpu_to_le16(EXT4_GOOD_OLD_INODE_SIZE);
567 	es->s_rev_level = cpu_to_le32(EXT4_DYNAMIC_REV);
568 	/* leave es->s_feature_*compat flags alone */
569 	/* es->s_uuid will be set by e2fsck if empty */
570 
571 	/*
572 	 * The rest of the superblock fields should be zero, and if not it
573 	 * means they are likely already in use, so leave them alone.  We
574 	 * can leave it up to e2fsck to clean up any inconsistencies there.
575 	 */
576 }
577 
578 /*
579  * Open the external journal device
580  */
581 static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb)
582 {
583 	struct block_device *bdev;
584 	char b[BDEVNAME_SIZE];
585 
586 	bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
587 	if (IS_ERR(bdev))
588 		goto fail;
589 	return bdev;
590 
591 fail:
592 	ext4_msg(sb, KERN_ERR, "failed to open journal device %s: %ld",
593 			__bdevname(dev, b), PTR_ERR(bdev));
594 	return NULL;
595 }
596 
597 /*
598  * Release the journal device
599  */
600 static int ext4_blkdev_put(struct block_device *bdev)
601 {
602 	bd_release(bdev);
603 	return blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
604 }
605 
606 static int ext4_blkdev_remove(struct ext4_sb_info *sbi)
607 {
608 	struct block_device *bdev;
609 	int ret = -ENODEV;
610 
611 	bdev = sbi->journal_bdev;
612 	if (bdev) {
613 		ret = ext4_blkdev_put(bdev);
614 		sbi->journal_bdev = NULL;
615 	}
616 	return ret;
617 }
618 
619 static inline struct inode *orphan_list_entry(struct list_head *l)
620 {
621 	return &list_entry(l, struct ext4_inode_info, i_orphan)->vfs_inode;
622 }
623 
624 static void dump_orphan_list(struct super_block *sb, struct ext4_sb_info *sbi)
625 {
626 	struct list_head *l;
627 
628 	ext4_msg(sb, KERN_ERR, "sb orphan head is %d",
629 		 le32_to_cpu(sbi->s_es->s_last_orphan));
630 
631 	printk(KERN_ERR "sb_info orphan list:\n");
632 	list_for_each(l, &sbi->s_orphan) {
633 		struct inode *inode = orphan_list_entry(l);
634 		printk(KERN_ERR "  "
635 		       "inode %s:%lu at %p: mode %o, nlink %d, next %d\n",
636 		       inode->i_sb->s_id, inode->i_ino, inode,
637 		       inode->i_mode, inode->i_nlink,
638 		       NEXT_ORPHAN(inode));
639 	}
640 }
641 
642 static void ext4_put_super(struct super_block *sb)
643 {
644 	struct ext4_sb_info *sbi = EXT4_SB(sb);
645 	struct ext4_super_block *es = sbi->s_es;
646 	int i, err;
647 
648 	flush_workqueue(sbi->dio_unwritten_wq);
649 	destroy_workqueue(sbi->dio_unwritten_wq);
650 
651 	lock_super(sb);
652 	lock_kernel();
653 	if (sb->s_dirt)
654 		ext4_commit_super(sb, 1);
655 
656 	if (sbi->s_journal) {
657 		err = jbd2_journal_destroy(sbi->s_journal);
658 		sbi->s_journal = NULL;
659 		if (err < 0)
660 			ext4_abort(sb, __func__,
661 				   "Couldn't clean up the journal");
662 	}
663 
664 	ext4_release_system_zone(sb);
665 	ext4_mb_release(sb);
666 	ext4_ext_release(sb);
667 	ext4_xattr_put_super(sb);
668 
669 	if (!(sb->s_flags & MS_RDONLY)) {
670 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
671 		es->s_state = cpu_to_le16(sbi->s_mount_state);
672 		ext4_commit_super(sb, 1);
673 	}
674 	if (sbi->s_proc) {
675 		remove_proc_entry(sb->s_id, ext4_proc_root);
676 	}
677 	kobject_del(&sbi->s_kobj);
678 
679 	for (i = 0; i < sbi->s_gdb_count; i++)
680 		brelse(sbi->s_group_desc[i]);
681 	kfree(sbi->s_group_desc);
682 	if (is_vmalloc_addr(sbi->s_flex_groups))
683 		vfree(sbi->s_flex_groups);
684 	else
685 		kfree(sbi->s_flex_groups);
686 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
687 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
688 	percpu_counter_destroy(&sbi->s_dirs_counter);
689 	percpu_counter_destroy(&sbi->s_dirtyblocks_counter);
690 	brelse(sbi->s_sbh);
691 #ifdef CONFIG_QUOTA
692 	for (i = 0; i < MAXQUOTAS; i++)
693 		kfree(sbi->s_qf_names[i]);
694 #endif
695 
696 	/* Debugging code just in case the in-memory inode orphan list
697 	 * isn't empty.  The on-disk one can be non-empty if we've
698 	 * detected an error and taken the fs readonly, but the
699 	 * in-memory list had better be clean by this point. */
700 	if (!list_empty(&sbi->s_orphan))
701 		dump_orphan_list(sb, sbi);
702 	J_ASSERT(list_empty(&sbi->s_orphan));
703 
704 	invalidate_bdev(sb->s_bdev);
705 	if (sbi->journal_bdev && sbi->journal_bdev != sb->s_bdev) {
706 		/*
707 		 * Invalidate the journal device's buffers.  We don't want them
708 		 * floating about in memory - the physical journal device may
709 		 * hotswapped, and it breaks the `ro-after' testing code.
710 		 */
711 		sync_blockdev(sbi->journal_bdev);
712 		invalidate_bdev(sbi->journal_bdev);
713 		ext4_blkdev_remove(sbi);
714 	}
715 	sb->s_fs_info = NULL;
716 	/*
717 	 * Now that we are completely done shutting down the
718 	 * superblock, we need to actually destroy the kobject.
719 	 */
720 	unlock_kernel();
721 	unlock_super(sb);
722 	kobject_put(&sbi->s_kobj);
723 	wait_for_completion(&sbi->s_kobj_unregister);
724 	kfree(sbi->s_blockgroup_lock);
725 	kfree(sbi);
726 }
727 
728 static struct kmem_cache *ext4_inode_cachep;
729 
730 /*
731  * Called inside transaction, so use GFP_NOFS
732  */
733 static struct inode *ext4_alloc_inode(struct super_block *sb)
734 {
735 	struct ext4_inode_info *ei;
736 
737 	ei = kmem_cache_alloc(ext4_inode_cachep, GFP_NOFS);
738 	if (!ei)
739 		return NULL;
740 
741 	ei->vfs_inode.i_version = 1;
742 	ei->vfs_inode.i_data.writeback_index = 0;
743 	memset(&ei->i_cached_extent, 0, sizeof(struct ext4_ext_cache));
744 	INIT_LIST_HEAD(&ei->i_prealloc_list);
745 	spin_lock_init(&ei->i_prealloc_lock);
746 	/*
747 	 * Note:  We can be called before EXT4_SB(sb)->s_journal is set,
748 	 * therefore it can be null here.  Don't check it, just initialize
749 	 * jinode.
750 	 */
751 	jbd2_journal_init_jbd_inode(&ei->jinode, &ei->vfs_inode);
752 	ei->i_reserved_data_blocks = 0;
753 	ei->i_reserved_meta_blocks = 0;
754 	ei->i_allocated_meta_blocks = 0;
755 	ei->i_da_metadata_calc_len = 0;
756 	ei->i_delalloc_reserved_flag = 0;
757 	spin_lock_init(&(ei->i_block_reservation_lock));
758 #ifdef CONFIG_QUOTA
759 	ei->i_reserved_quota = 0;
760 #endif
761 	INIT_LIST_HEAD(&ei->i_completed_io_list);
762 	spin_lock_init(&ei->i_completed_io_lock);
763 	ei->cur_aio_dio = NULL;
764 	ei->i_sync_tid = 0;
765 	ei->i_datasync_tid = 0;
766 
767 	return &ei->vfs_inode;
768 }
769 
770 static void ext4_destroy_inode(struct inode *inode)
771 {
772 	if (!list_empty(&(EXT4_I(inode)->i_orphan))) {
773 		ext4_msg(inode->i_sb, KERN_ERR,
774 			 "Inode %lu (%p): orphan list check failed!",
775 			 inode->i_ino, EXT4_I(inode));
776 		print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 16, 4,
777 				EXT4_I(inode), sizeof(struct ext4_inode_info),
778 				true);
779 		dump_stack();
780 	}
781 	kmem_cache_free(ext4_inode_cachep, EXT4_I(inode));
782 }
783 
784 static void init_once(void *foo)
785 {
786 	struct ext4_inode_info *ei = (struct ext4_inode_info *) foo;
787 
788 	INIT_LIST_HEAD(&ei->i_orphan);
789 #ifdef CONFIG_EXT4_FS_XATTR
790 	init_rwsem(&ei->xattr_sem);
791 #endif
792 	init_rwsem(&ei->i_data_sem);
793 	inode_init_once(&ei->vfs_inode);
794 }
795 
796 static int init_inodecache(void)
797 {
798 	ext4_inode_cachep = kmem_cache_create("ext4_inode_cache",
799 					     sizeof(struct ext4_inode_info),
800 					     0, (SLAB_RECLAIM_ACCOUNT|
801 						SLAB_MEM_SPREAD),
802 					     init_once);
803 	if (ext4_inode_cachep == NULL)
804 		return -ENOMEM;
805 	return 0;
806 }
807 
808 static void destroy_inodecache(void)
809 {
810 	kmem_cache_destroy(ext4_inode_cachep);
811 }
812 
813 static void ext4_clear_inode(struct inode *inode)
814 {
815 	dquot_drop(inode);
816 	ext4_discard_preallocations(inode);
817 	if (EXT4_JOURNAL(inode))
818 		jbd2_journal_release_jbd_inode(EXT4_SB(inode->i_sb)->s_journal,
819 				       &EXT4_I(inode)->jinode);
820 }
821 
822 static inline void ext4_show_quota_options(struct seq_file *seq,
823 					   struct super_block *sb)
824 {
825 #if defined(CONFIG_QUOTA)
826 	struct ext4_sb_info *sbi = EXT4_SB(sb);
827 
828 	if (sbi->s_jquota_fmt) {
829 		char *fmtname = "";
830 
831 		switch (sbi->s_jquota_fmt) {
832 		case QFMT_VFS_OLD:
833 			fmtname = "vfsold";
834 			break;
835 		case QFMT_VFS_V0:
836 			fmtname = "vfsv0";
837 			break;
838 		case QFMT_VFS_V1:
839 			fmtname = "vfsv1";
840 			break;
841 		}
842 		seq_printf(seq, ",jqfmt=%s", fmtname);
843 	}
844 
845 	if (sbi->s_qf_names[USRQUOTA])
846 		seq_printf(seq, ",usrjquota=%s", sbi->s_qf_names[USRQUOTA]);
847 
848 	if (sbi->s_qf_names[GRPQUOTA])
849 		seq_printf(seq, ",grpjquota=%s", sbi->s_qf_names[GRPQUOTA]);
850 
851 	if (test_opt(sb, USRQUOTA))
852 		seq_puts(seq, ",usrquota");
853 
854 	if (test_opt(sb, GRPQUOTA))
855 		seq_puts(seq, ",grpquota");
856 #endif
857 }
858 
859 /*
860  * Show an option if
861  *  - it's set to a non-default value OR
862  *  - if the per-sb default is different from the global default
863  */
864 static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs)
865 {
866 	int def_errors;
867 	unsigned long def_mount_opts;
868 	struct super_block *sb = vfs->mnt_sb;
869 	struct ext4_sb_info *sbi = EXT4_SB(sb);
870 	struct ext4_super_block *es = sbi->s_es;
871 
872 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
873 	def_errors     = le16_to_cpu(es->s_errors);
874 
875 	if (sbi->s_sb_block != 1)
876 		seq_printf(seq, ",sb=%llu", sbi->s_sb_block);
877 	if (test_opt(sb, MINIX_DF))
878 		seq_puts(seq, ",minixdf");
879 	if (test_opt(sb, GRPID) && !(def_mount_opts & EXT4_DEFM_BSDGROUPS))
880 		seq_puts(seq, ",grpid");
881 	if (!test_opt(sb, GRPID) && (def_mount_opts & EXT4_DEFM_BSDGROUPS))
882 		seq_puts(seq, ",nogrpid");
883 	if (sbi->s_resuid != EXT4_DEF_RESUID ||
884 	    le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID) {
885 		seq_printf(seq, ",resuid=%u", sbi->s_resuid);
886 	}
887 	if (sbi->s_resgid != EXT4_DEF_RESGID ||
888 	    le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID) {
889 		seq_printf(seq, ",resgid=%u", sbi->s_resgid);
890 	}
891 	if (test_opt(sb, ERRORS_RO)) {
892 		if (def_errors == EXT4_ERRORS_PANIC ||
893 		    def_errors == EXT4_ERRORS_CONTINUE) {
894 			seq_puts(seq, ",errors=remount-ro");
895 		}
896 	}
897 	if (test_opt(sb, ERRORS_CONT) && def_errors != EXT4_ERRORS_CONTINUE)
898 		seq_puts(seq, ",errors=continue");
899 	if (test_opt(sb, ERRORS_PANIC) && def_errors != EXT4_ERRORS_PANIC)
900 		seq_puts(seq, ",errors=panic");
901 	if (test_opt(sb, NO_UID32) && !(def_mount_opts & EXT4_DEFM_UID16))
902 		seq_puts(seq, ",nouid32");
903 	if (test_opt(sb, DEBUG) && !(def_mount_opts & EXT4_DEFM_DEBUG))
904 		seq_puts(seq, ",debug");
905 	if (test_opt(sb, OLDALLOC))
906 		seq_puts(seq, ",oldalloc");
907 #ifdef CONFIG_EXT4_FS_XATTR
908 	if (test_opt(sb, XATTR_USER) &&
909 		!(def_mount_opts & EXT4_DEFM_XATTR_USER))
910 		seq_puts(seq, ",user_xattr");
911 	if (!test_opt(sb, XATTR_USER) &&
912 	    (def_mount_opts & EXT4_DEFM_XATTR_USER)) {
913 		seq_puts(seq, ",nouser_xattr");
914 	}
915 #endif
916 #ifdef CONFIG_EXT4_FS_POSIX_ACL
917 	if (test_opt(sb, POSIX_ACL) && !(def_mount_opts & EXT4_DEFM_ACL))
918 		seq_puts(seq, ",acl");
919 	if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT4_DEFM_ACL))
920 		seq_puts(seq, ",noacl");
921 #endif
922 	if (sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ) {
923 		seq_printf(seq, ",commit=%u",
924 			   (unsigned) (sbi->s_commit_interval / HZ));
925 	}
926 	if (sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME) {
927 		seq_printf(seq, ",min_batch_time=%u",
928 			   (unsigned) sbi->s_min_batch_time);
929 	}
930 	if (sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME) {
931 		seq_printf(seq, ",max_batch_time=%u",
932 			   (unsigned) sbi->s_min_batch_time);
933 	}
934 
935 	/*
936 	 * We're changing the default of barrier mount option, so
937 	 * let's always display its mount state so it's clear what its
938 	 * status is.
939 	 */
940 	seq_puts(seq, ",barrier=");
941 	seq_puts(seq, test_opt(sb, BARRIER) ? "1" : "0");
942 	if (test_opt(sb, JOURNAL_ASYNC_COMMIT))
943 		seq_puts(seq, ",journal_async_commit");
944 	if (test_opt(sb, NOBH))
945 		seq_puts(seq, ",nobh");
946 	if (test_opt(sb, I_VERSION))
947 		seq_puts(seq, ",i_version");
948 	if (!test_opt(sb, DELALLOC))
949 		seq_puts(seq, ",nodelalloc");
950 
951 
952 	if (sbi->s_stripe)
953 		seq_printf(seq, ",stripe=%lu", sbi->s_stripe);
954 	/*
955 	 * journal mode get enabled in different ways
956 	 * So just print the value even if we didn't specify it
957 	 */
958 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
959 		seq_puts(seq, ",data=journal");
960 	else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
961 		seq_puts(seq, ",data=ordered");
962 	else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
963 		seq_puts(seq, ",data=writeback");
964 
965 	if (sbi->s_inode_readahead_blks != EXT4_DEF_INODE_READAHEAD_BLKS)
966 		seq_printf(seq, ",inode_readahead_blks=%u",
967 			   sbi->s_inode_readahead_blks);
968 
969 	if (test_opt(sb, DATA_ERR_ABORT))
970 		seq_puts(seq, ",data_err=abort");
971 
972 	if (test_opt(sb, NO_AUTO_DA_ALLOC))
973 		seq_puts(seq, ",noauto_da_alloc");
974 
975 	if (test_opt(sb, DISCARD))
976 		seq_puts(seq, ",discard");
977 
978 	if (test_opt(sb, NOLOAD))
979 		seq_puts(seq, ",norecovery");
980 
981 	if (test_opt(sb, DIOREAD_NOLOCK))
982 		seq_puts(seq, ",dioread_nolock");
983 
984 	ext4_show_quota_options(seq, sb);
985 
986 	return 0;
987 }
988 
989 static struct inode *ext4_nfs_get_inode(struct super_block *sb,
990 					u64 ino, u32 generation)
991 {
992 	struct inode *inode;
993 
994 	if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
995 		return ERR_PTR(-ESTALE);
996 	if (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
997 		return ERR_PTR(-ESTALE);
998 
999 	/* iget isn't really right if the inode is currently unallocated!!
1000 	 *
1001 	 * ext4_read_inode will return a bad_inode if the inode had been
1002 	 * deleted, so we should be safe.
1003 	 *
1004 	 * Currently we don't know the generation for parent directory, so
1005 	 * a generation of 0 means "accept any"
1006 	 */
1007 	inode = ext4_iget(sb, ino);
1008 	if (IS_ERR(inode))
1009 		return ERR_CAST(inode);
1010 	if (generation && inode->i_generation != generation) {
1011 		iput(inode);
1012 		return ERR_PTR(-ESTALE);
1013 	}
1014 
1015 	return inode;
1016 }
1017 
1018 static struct dentry *ext4_fh_to_dentry(struct super_block *sb, struct fid *fid,
1019 					int fh_len, int fh_type)
1020 {
1021 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
1022 				    ext4_nfs_get_inode);
1023 }
1024 
1025 static struct dentry *ext4_fh_to_parent(struct super_block *sb, struct fid *fid,
1026 					int fh_len, int fh_type)
1027 {
1028 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
1029 				    ext4_nfs_get_inode);
1030 }
1031 
1032 /*
1033  * Try to release metadata pages (indirect blocks, directories) which are
1034  * mapped via the block device.  Since these pages could have journal heads
1035  * which would prevent try_to_free_buffers() from freeing them, we must use
1036  * jbd2 layer's try_to_free_buffers() function to release them.
1037  */
1038 static int bdev_try_to_free_page(struct super_block *sb, struct page *page,
1039 				 gfp_t wait)
1040 {
1041 	journal_t *journal = EXT4_SB(sb)->s_journal;
1042 
1043 	WARN_ON(PageChecked(page));
1044 	if (!page_has_buffers(page))
1045 		return 0;
1046 	if (journal)
1047 		return jbd2_journal_try_to_free_buffers(journal, page,
1048 							wait & ~__GFP_WAIT);
1049 	return try_to_free_buffers(page);
1050 }
1051 
1052 #ifdef CONFIG_QUOTA
1053 #define QTYPE2NAME(t) ((t) == USRQUOTA ? "user" : "group")
1054 #define QTYPE2MOPT(on, t) ((t) == USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
1055 
1056 static int ext4_write_dquot(struct dquot *dquot);
1057 static int ext4_acquire_dquot(struct dquot *dquot);
1058 static int ext4_release_dquot(struct dquot *dquot);
1059 static int ext4_mark_dquot_dirty(struct dquot *dquot);
1060 static int ext4_write_info(struct super_block *sb, int type);
1061 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
1062 				char *path, int remount);
1063 static int ext4_quota_on_mount(struct super_block *sb, int type);
1064 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
1065 			       size_t len, loff_t off);
1066 static ssize_t ext4_quota_write(struct super_block *sb, int type,
1067 				const char *data, size_t len, loff_t off);
1068 
1069 static const struct dquot_operations ext4_quota_operations = {
1070 #ifdef CONFIG_QUOTA
1071 	.get_reserved_space = ext4_get_reserved_space,
1072 #endif
1073 	.write_dquot	= ext4_write_dquot,
1074 	.acquire_dquot	= ext4_acquire_dquot,
1075 	.release_dquot	= ext4_release_dquot,
1076 	.mark_dirty	= ext4_mark_dquot_dirty,
1077 	.write_info	= ext4_write_info,
1078 	.alloc_dquot	= dquot_alloc,
1079 	.destroy_dquot	= dquot_destroy,
1080 };
1081 
1082 static const struct quotactl_ops ext4_qctl_operations = {
1083 	.quota_on	= ext4_quota_on,
1084 	.quota_off	= vfs_quota_off,
1085 	.quota_sync	= vfs_quota_sync,
1086 	.get_info	= vfs_get_dqinfo,
1087 	.set_info	= vfs_set_dqinfo,
1088 	.get_dqblk	= vfs_get_dqblk,
1089 	.set_dqblk	= vfs_set_dqblk
1090 };
1091 #endif
1092 
1093 static const struct super_operations ext4_sops = {
1094 	.alloc_inode	= ext4_alloc_inode,
1095 	.destroy_inode	= ext4_destroy_inode,
1096 	.write_inode	= ext4_write_inode,
1097 	.dirty_inode	= ext4_dirty_inode,
1098 	.delete_inode	= ext4_delete_inode,
1099 	.put_super	= ext4_put_super,
1100 	.sync_fs	= ext4_sync_fs,
1101 	.freeze_fs	= ext4_freeze,
1102 	.unfreeze_fs	= ext4_unfreeze,
1103 	.statfs		= ext4_statfs,
1104 	.remount_fs	= ext4_remount,
1105 	.clear_inode	= ext4_clear_inode,
1106 	.show_options	= ext4_show_options,
1107 #ifdef CONFIG_QUOTA
1108 	.quota_read	= ext4_quota_read,
1109 	.quota_write	= ext4_quota_write,
1110 #endif
1111 	.bdev_try_to_free_page = bdev_try_to_free_page,
1112 };
1113 
1114 static const struct super_operations ext4_nojournal_sops = {
1115 	.alloc_inode	= ext4_alloc_inode,
1116 	.destroy_inode	= ext4_destroy_inode,
1117 	.write_inode	= ext4_write_inode,
1118 	.dirty_inode	= ext4_dirty_inode,
1119 	.delete_inode	= ext4_delete_inode,
1120 	.write_super	= ext4_write_super,
1121 	.put_super	= ext4_put_super,
1122 	.statfs		= ext4_statfs,
1123 	.remount_fs	= ext4_remount,
1124 	.clear_inode	= ext4_clear_inode,
1125 	.show_options	= ext4_show_options,
1126 #ifdef CONFIG_QUOTA
1127 	.quota_read	= ext4_quota_read,
1128 	.quota_write	= ext4_quota_write,
1129 #endif
1130 	.bdev_try_to_free_page = bdev_try_to_free_page,
1131 };
1132 
1133 static const struct export_operations ext4_export_ops = {
1134 	.fh_to_dentry = ext4_fh_to_dentry,
1135 	.fh_to_parent = ext4_fh_to_parent,
1136 	.get_parent = ext4_get_parent,
1137 };
1138 
1139 enum {
1140 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
1141 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
1142 	Opt_nouid32, Opt_debug, Opt_oldalloc, Opt_orlov,
1143 	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
1144 	Opt_auto_da_alloc, Opt_noauto_da_alloc, Opt_noload, Opt_nobh, Opt_bh,
1145 	Opt_commit, Opt_min_batch_time, Opt_max_batch_time,
1146 	Opt_journal_update, Opt_journal_dev,
1147 	Opt_journal_checksum, Opt_journal_async_commit,
1148 	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
1149 	Opt_data_err_abort, Opt_data_err_ignore,
1150 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
1151 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
1152 	Opt_noquota, Opt_ignore, Opt_barrier, Opt_nobarrier, Opt_err,
1153 	Opt_resize, Opt_usrquota, Opt_grpquota, Opt_i_version,
1154 	Opt_stripe, Opt_delalloc, Opt_nodelalloc,
1155 	Opt_block_validity, Opt_noblock_validity,
1156 	Opt_inode_readahead_blks, Opt_journal_ioprio,
1157 	Opt_dioread_nolock, Opt_dioread_lock,
1158 	Opt_discard, Opt_nodiscard,
1159 };
1160 
1161 static const match_table_t tokens = {
1162 	{Opt_bsd_df, "bsddf"},
1163 	{Opt_minix_df, "minixdf"},
1164 	{Opt_grpid, "grpid"},
1165 	{Opt_grpid, "bsdgroups"},
1166 	{Opt_nogrpid, "nogrpid"},
1167 	{Opt_nogrpid, "sysvgroups"},
1168 	{Opt_resgid, "resgid=%u"},
1169 	{Opt_resuid, "resuid=%u"},
1170 	{Opt_sb, "sb=%u"},
1171 	{Opt_err_cont, "errors=continue"},
1172 	{Opt_err_panic, "errors=panic"},
1173 	{Opt_err_ro, "errors=remount-ro"},
1174 	{Opt_nouid32, "nouid32"},
1175 	{Opt_debug, "debug"},
1176 	{Opt_oldalloc, "oldalloc"},
1177 	{Opt_orlov, "orlov"},
1178 	{Opt_user_xattr, "user_xattr"},
1179 	{Opt_nouser_xattr, "nouser_xattr"},
1180 	{Opt_acl, "acl"},
1181 	{Opt_noacl, "noacl"},
1182 	{Opt_noload, "noload"},
1183 	{Opt_noload, "norecovery"},
1184 	{Opt_nobh, "nobh"},
1185 	{Opt_bh, "bh"},
1186 	{Opt_commit, "commit=%u"},
1187 	{Opt_min_batch_time, "min_batch_time=%u"},
1188 	{Opt_max_batch_time, "max_batch_time=%u"},
1189 	{Opt_journal_update, "journal=update"},
1190 	{Opt_journal_dev, "journal_dev=%u"},
1191 	{Opt_journal_checksum, "journal_checksum"},
1192 	{Opt_journal_async_commit, "journal_async_commit"},
1193 	{Opt_abort, "abort"},
1194 	{Opt_data_journal, "data=journal"},
1195 	{Opt_data_ordered, "data=ordered"},
1196 	{Opt_data_writeback, "data=writeback"},
1197 	{Opt_data_err_abort, "data_err=abort"},
1198 	{Opt_data_err_ignore, "data_err=ignore"},
1199 	{Opt_offusrjquota, "usrjquota="},
1200 	{Opt_usrjquota, "usrjquota=%s"},
1201 	{Opt_offgrpjquota, "grpjquota="},
1202 	{Opt_grpjquota, "grpjquota=%s"},
1203 	{Opt_jqfmt_vfsold, "jqfmt=vfsold"},
1204 	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
1205 	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
1206 	{Opt_grpquota, "grpquota"},
1207 	{Opt_noquota, "noquota"},
1208 	{Opt_quota, "quota"},
1209 	{Opt_usrquota, "usrquota"},
1210 	{Opt_barrier, "barrier=%u"},
1211 	{Opt_barrier, "barrier"},
1212 	{Opt_nobarrier, "nobarrier"},
1213 	{Opt_i_version, "i_version"},
1214 	{Opt_stripe, "stripe=%u"},
1215 	{Opt_resize, "resize"},
1216 	{Opt_delalloc, "delalloc"},
1217 	{Opt_nodelalloc, "nodelalloc"},
1218 	{Opt_block_validity, "block_validity"},
1219 	{Opt_noblock_validity, "noblock_validity"},
1220 	{Opt_inode_readahead_blks, "inode_readahead_blks=%u"},
1221 	{Opt_journal_ioprio, "journal_ioprio=%u"},
1222 	{Opt_auto_da_alloc, "auto_da_alloc=%u"},
1223 	{Opt_auto_da_alloc, "auto_da_alloc"},
1224 	{Opt_noauto_da_alloc, "noauto_da_alloc"},
1225 	{Opt_dioread_nolock, "dioread_nolock"},
1226 	{Opt_dioread_lock, "dioread_lock"},
1227 	{Opt_discard, "discard"},
1228 	{Opt_nodiscard, "nodiscard"},
1229 	{Opt_err, NULL},
1230 };
1231 
1232 static ext4_fsblk_t get_sb_block(void **data)
1233 {
1234 	ext4_fsblk_t	sb_block;
1235 	char		*options = (char *) *data;
1236 
1237 	if (!options || strncmp(options, "sb=", 3) != 0)
1238 		return 1;	/* Default location */
1239 
1240 	options += 3;
1241 	/* TODO: use simple_strtoll with >32bit ext4 */
1242 	sb_block = simple_strtoul(options, &options, 0);
1243 	if (*options && *options != ',') {
1244 		printk(KERN_ERR "EXT4-fs: Invalid sb specification: %s\n",
1245 		       (char *) *data);
1246 		return 1;
1247 	}
1248 	if (*options == ',')
1249 		options++;
1250 	*data = (void *) options;
1251 
1252 	return sb_block;
1253 }
1254 
1255 #define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))
1256 static char deprecated_msg[] = "Mount option \"%s\" will be removed by %s\n"
1257 	"Contact linux-ext4@vger.kernel.org if you think we should keep it.\n";
1258 
1259 #ifdef CONFIG_QUOTA
1260 static int set_qf_name(struct super_block *sb, int qtype, substring_t *args)
1261 {
1262 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1263 	char *qname;
1264 
1265 	if (sb_any_quota_loaded(sb) &&
1266 		!sbi->s_qf_names[qtype]) {
1267 		ext4_msg(sb, KERN_ERR,
1268 			"Cannot change journaled "
1269 			"quota options when quota turned on");
1270 		return 0;
1271 	}
1272 	qname = match_strdup(args);
1273 	if (!qname) {
1274 		ext4_msg(sb, KERN_ERR,
1275 			"Not enough memory for storing quotafile name");
1276 		return 0;
1277 	}
1278 	if (sbi->s_qf_names[qtype] &&
1279 		strcmp(sbi->s_qf_names[qtype], qname)) {
1280 		ext4_msg(sb, KERN_ERR,
1281 			"%s quota file already specified", QTYPE2NAME(qtype));
1282 		kfree(qname);
1283 		return 0;
1284 	}
1285 	sbi->s_qf_names[qtype] = qname;
1286 	if (strchr(sbi->s_qf_names[qtype], '/')) {
1287 		ext4_msg(sb, KERN_ERR,
1288 			"quotafile must be on filesystem root");
1289 		kfree(sbi->s_qf_names[qtype]);
1290 		sbi->s_qf_names[qtype] = NULL;
1291 		return 0;
1292 	}
1293 	set_opt(sbi->s_mount_opt, QUOTA);
1294 	return 1;
1295 }
1296 
1297 static int clear_qf_name(struct super_block *sb, int qtype)
1298 {
1299 
1300 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1301 
1302 	if (sb_any_quota_loaded(sb) &&
1303 		sbi->s_qf_names[qtype]) {
1304 		ext4_msg(sb, KERN_ERR, "Cannot change journaled quota options"
1305 			" when quota turned on");
1306 		return 0;
1307 	}
1308 	/*
1309 	 * The space will be released later when all options are confirmed
1310 	 * to be correct
1311 	 */
1312 	sbi->s_qf_names[qtype] = NULL;
1313 	return 1;
1314 }
1315 #endif
1316 
1317 static int parse_options(char *options, struct super_block *sb,
1318 			 unsigned long *journal_devnum,
1319 			 unsigned int *journal_ioprio,
1320 			 ext4_fsblk_t *n_blocks_count, int is_remount)
1321 {
1322 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1323 	char *p;
1324 	substring_t args[MAX_OPT_ARGS];
1325 	int data_opt = 0;
1326 	int option;
1327 #ifdef CONFIG_QUOTA
1328 	int qfmt;
1329 #endif
1330 
1331 	if (!options)
1332 		return 1;
1333 
1334 	while ((p = strsep(&options, ",")) != NULL) {
1335 		int token;
1336 		if (!*p)
1337 			continue;
1338 
1339 		/*
1340 		 * Initialize args struct so we know whether arg was
1341 		 * found; some options take optional arguments.
1342 		 */
1343 		args[0].to = args[0].from = 0;
1344 		token = match_token(p, tokens, args);
1345 		switch (token) {
1346 		case Opt_bsd_df:
1347 			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
1348 			clear_opt(sbi->s_mount_opt, MINIX_DF);
1349 			break;
1350 		case Opt_minix_df:
1351 			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
1352 			set_opt(sbi->s_mount_opt, MINIX_DF);
1353 
1354 			break;
1355 		case Opt_grpid:
1356 			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
1357 			set_opt(sbi->s_mount_opt, GRPID);
1358 
1359 			break;
1360 		case Opt_nogrpid:
1361 			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
1362 			clear_opt(sbi->s_mount_opt, GRPID);
1363 
1364 			break;
1365 		case Opt_resuid:
1366 			if (match_int(&args[0], &option))
1367 				return 0;
1368 			sbi->s_resuid = option;
1369 			break;
1370 		case Opt_resgid:
1371 			if (match_int(&args[0], &option))
1372 				return 0;
1373 			sbi->s_resgid = option;
1374 			break;
1375 		case Opt_sb:
1376 			/* handled by get_sb_block() instead of here */
1377 			/* *sb_block = match_int(&args[0]); */
1378 			break;
1379 		case Opt_err_panic:
1380 			clear_opt(sbi->s_mount_opt, ERRORS_CONT);
1381 			clear_opt(sbi->s_mount_opt, ERRORS_RO);
1382 			set_opt(sbi->s_mount_opt, ERRORS_PANIC);
1383 			break;
1384 		case Opt_err_ro:
1385 			clear_opt(sbi->s_mount_opt, ERRORS_CONT);
1386 			clear_opt(sbi->s_mount_opt, ERRORS_PANIC);
1387 			set_opt(sbi->s_mount_opt, ERRORS_RO);
1388 			break;
1389 		case Opt_err_cont:
1390 			clear_opt(sbi->s_mount_opt, ERRORS_RO);
1391 			clear_opt(sbi->s_mount_opt, ERRORS_PANIC);
1392 			set_opt(sbi->s_mount_opt, ERRORS_CONT);
1393 			break;
1394 		case Opt_nouid32:
1395 			set_opt(sbi->s_mount_opt, NO_UID32);
1396 			break;
1397 		case Opt_debug:
1398 			set_opt(sbi->s_mount_opt, DEBUG);
1399 			break;
1400 		case Opt_oldalloc:
1401 			set_opt(sbi->s_mount_opt, OLDALLOC);
1402 			break;
1403 		case Opt_orlov:
1404 			clear_opt(sbi->s_mount_opt, OLDALLOC);
1405 			break;
1406 #ifdef CONFIG_EXT4_FS_XATTR
1407 		case Opt_user_xattr:
1408 			set_opt(sbi->s_mount_opt, XATTR_USER);
1409 			break;
1410 		case Opt_nouser_xattr:
1411 			clear_opt(sbi->s_mount_opt, XATTR_USER);
1412 			break;
1413 #else
1414 		case Opt_user_xattr:
1415 		case Opt_nouser_xattr:
1416 			ext4_msg(sb, KERN_ERR, "(no)user_xattr options not supported");
1417 			break;
1418 #endif
1419 #ifdef CONFIG_EXT4_FS_POSIX_ACL
1420 		case Opt_acl:
1421 			set_opt(sbi->s_mount_opt, POSIX_ACL);
1422 			break;
1423 		case Opt_noacl:
1424 			clear_opt(sbi->s_mount_opt, POSIX_ACL);
1425 			break;
1426 #else
1427 		case Opt_acl:
1428 		case Opt_noacl:
1429 			ext4_msg(sb, KERN_ERR, "(no)acl options not supported");
1430 			break;
1431 #endif
1432 		case Opt_journal_update:
1433 			/* @@@ FIXME */
1434 			/* Eventually we will want to be able to create
1435 			   a journal file here.  For now, only allow the
1436 			   user to specify an existing inode to be the
1437 			   journal file. */
1438 			if (is_remount) {
1439 				ext4_msg(sb, KERN_ERR,
1440 					 "Cannot specify journal on remount");
1441 				return 0;
1442 			}
1443 			set_opt(sbi->s_mount_opt, UPDATE_JOURNAL);
1444 			break;
1445 		case Opt_journal_dev:
1446 			if (is_remount) {
1447 				ext4_msg(sb, KERN_ERR,
1448 					"Cannot specify journal on remount");
1449 				return 0;
1450 			}
1451 			if (match_int(&args[0], &option))
1452 				return 0;
1453 			*journal_devnum = option;
1454 			break;
1455 		case Opt_journal_checksum:
1456 			set_opt(sbi->s_mount_opt, JOURNAL_CHECKSUM);
1457 			break;
1458 		case Opt_journal_async_commit:
1459 			set_opt(sbi->s_mount_opt, JOURNAL_ASYNC_COMMIT);
1460 			set_opt(sbi->s_mount_opt, JOURNAL_CHECKSUM);
1461 			break;
1462 		case Opt_noload:
1463 			set_opt(sbi->s_mount_opt, NOLOAD);
1464 			break;
1465 		case Opt_commit:
1466 			if (match_int(&args[0], &option))
1467 				return 0;
1468 			if (option < 0)
1469 				return 0;
1470 			if (option == 0)
1471 				option = JBD2_DEFAULT_MAX_COMMIT_AGE;
1472 			sbi->s_commit_interval = HZ * option;
1473 			break;
1474 		case Opt_max_batch_time:
1475 			if (match_int(&args[0], &option))
1476 				return 0;
1477 			if (option < 0)
1478 				return 0;
1479 			if (option == 0)
1480 				option = EXT4_DEF_MAX_BATCH_TIME;
1481 			sbi->s_max_batch_time = option;
1482 			break;
1483 		case Opt_min_batch_time:
1484 			if (match_int(&args[0], &option))
1485 				return 0;
1486 			if (option < 0)
1487 				return 0;
1488 			sbi->s_min_batch_time = option;
1489 			break;
1490 		case Opt_data_journal:
1491 			data_opt = EXT4_MOUNT_JOURNAL_DATA;
1492 			goto datacheck;
1493 		case Opt_data_ordered:
1494 			data_opt = EXT4_MOUNT_ORDERED_DATA;
1495 			goto datacheck;
1496 		case Opt_data_writeback:
1497 			data_opt = EXT4_MOUNT_WRITEBACK_DATA;
1498 		datacheck:
1499 			if (is_remount) {
1500 				if (test_opt(sb, DATA_FLAGS) != data_opt) {
1501 					ext4_msg(sb, KERN_ERR,
1502 						"Cannot change data mode on remount");
1503 					return 0;
1504 				}
1505 			} else {
1506 				clear_opt(sbi->s_mount_opt, DATA_FLAGS);
1507 				sbi->s_mount_opt |= data_opt;
1508 			}
1509 			break;
1510 		case Opt_data_err_abort:
1511 			set_opt(sbi->s_mount_opt, DATA_ERR_ABORT);
1512 			break;
1513 		case Opt_data_err_ignore:
1514 			clear_opt(sbi->s_mount_opt, DATA_ERR_ABORT);
1515 			break;
1516 #ifdef CONFIG_QUOTA
1517 		case Opt_usrjquota:
1518 			if (!set_qf_name(sb, USRQUOTA, &args[0]))
1519 				return 0;
1520 			break;
1521 		case Opt_grpjquota:
1522 			if (!set_qf_name(sb, GRPQUOTA, &args[0]))
1523 				return 0;
1524 			break;
1525 		case Opt_offusrjquota:
1526 			if (!clear_qf_name(sb, USRQUOTA))
1527 				return 0;
1528 			break;
1529 		case Opt_offgrpjquota:
1530 			if (!clear_qf_name(sb, GRPQUOTA))
1531 				return 0;
1532 			break;
1533 
1534 		case Opt_jqfmt_vfsold:
1535 			qfmt = QFMT_VFS_OLD;
1536 			goto set_qf_format;
1537 		case Opt_jqfmt_vfsv0:
1538 			qfmt = QFMT_VFS_V0;
1539 			goto set_qf_format;
1540 		case Opt_jqfmt_vfsv1:
1541 			qfmt = QFMT_VFS_V1;
1542 set_qf_format:
1543 			if (sb_any_quota_loaded(sb) &&
1544 			    sbi->s_jquota_fmt != qfmt) {
1545 				ext4_msg(sb, KERN_ERR, "Cannot change "
1546 					"journaled quota options when "
1547 					"quota turned on");
1548 				return 0;
1549 			}
1550 			sbi->s_jquota_fmt = qfmt;
1551 			break;
1552 		case Opt_quota:
1553 		case Opt_usrquota:
1554 			set_opt(sbi->s_mount_opt, QUOTA);
1555 			set_opt(sbi->s_mount_opt, USRQUOTA);
1556 			break;
1557 		case Opt_grpquota:
1558 			set_opt(sbi->s_mount_opt, QUOTA);
1559 			set_opt(sbi->s_mount_opt, GRPQUOTA);
1560 			break;
1561 		case Opt_noquota:
1562 			if (sb_any_quota_loaded(sb)) {
1563 				ext4_msg(sb, KERN_ERR, "Cannot change quota "
1564 					"options when quota turned on");
1565 				return 0;
1566 			}
1567 			clear_opt(sbi->s_mount_opt, QUOTA);
1568 			clear_opt(sbi->s_mount_opt, USRQUOTA);
1569 			clear_opt(sbi->s_mount_opt, GRPQUOTA);
1570 			break;
1571 #else
1572 		case Opt_quota:
1573 		case Opt_usrquota:
1574 		case Opt_grpquota:
1575 			ext4_msg(sb, KERN_ERR,
1576 				"quota options not supported");
1577 			break;
1578 		case Opt_usrjquota:
1579 		case Opt_grpjquota:
1580 		case Opt_offusrjquota:
1581 		case Opt_offgrpjquota:
1582 		case Opt_jqfmt_vfsold:
1583 		case Opt_jqfmt_vfsv0:
1584 		case Opt_jqfmt_vfsv1:
1585 			ext4_msg(sb, KERN_ERR,
1586 				"journaled quota options not supported");
1587 			break;
1588 		case Opt_noquota:
1589 			break;
1590 #endif
1591 		case Opt_abort:
1592 			sbi->s_mount_flags |= EXT4_MF_FS_ABORTED;
1593 			break;
1594 		case Opt_nobarrier:
1595 			clear_opt(sbi->s_mount_opt, BARRIER);
1596 			break;
1597 		case Opt_barrier:
1598 			if (args[0].from) {
1599 				if (match_int(&args[0], &option))
1600 					return 0;
1601 			} else
1602 				option = 1;	/* No argument, default to 1 */
1603 			if (option)
1604 				set_opt(sbi->s_mount_opt, BARRIER);
1605 			else
1606 				clear_opt(sbi->s_mount_opt, BARRIER);
1607 			break;
1608 		case Opt_ignore:
1609 			break;
1610 		case Opt_resize:
1611 			if (!is_remount) {
1612 				ext4_msg(sb, KERN_ERR,
1613 					"resize option only available "
1614 					"for remount");
1615 				return 0;
1616 			}
1617 			if (match_int(&args[0], &option) != 0)
1618 				return 0;
1619 			*n_blocks_count = option;
1620 			break;
1621 		case Opt_nobh:
1622 			set_opt(sbi->s_mount_opt, NOBH);
1623 			break;
1624 		case Opt_bh:
1625 			clear_opt(sbi->s_mount_opt, NOBH);
1626 			break;
1627 		case Opt_i_version:
1628 			set_opt(sbi->s_mount_opt, I_VERSION);
1629 			sb->s_flags |= MS_I_VERSION;
1630 			break;
1631 		case Opt_nodelalloc:
1632 			clear_opt(sbi->s_mount_opt, DELALLOC);
1633 			break;
1634 		case Opt_stripe:
1635 			if (match_int(&args[0], &option))
1636 				return 0;
1637 			if (option < 0)
1638 				return 0;
1639 			sbi->s_stripe = option;
1640 			break;
1641 		case Opt_delalloc:
1642 			set_opt(sbi->s_mount_opt, DELALLOC);
1643 			break;
1644 		case Opt_block_validity:
1645 			set_opt(sbi->s_mount_opt, BLOCK_VALIDITY);
1646 			break;
1647 		case Opt_noblock_validity:
1648 			clear_opt(sbi->s_mount_opt, BLOCK_VALIDITY);
1649 			break;
1650 		case Opt_inode_readahead_blks:
1651 			if (match_int(&args[0], &option))
1652 				return 0;
1653 			if (option < 0 || option > (1 << 30))
1654 				return 0;
1655 			if (!is_power_of_2(option)) {
1656 				ext4_msg(sb, KERN_ERR,
1657 					 "EXT4-fs: inode_readahead_blks"
1658 					 " must be a power of 2");
1659 				return 0;
1660 			}
1661 			sbi->s_inode_readahead_blks = option;
1662 			break;
1663 		case Opt_journal_ioprio:
1664 			if (match_int(&args[0], &option))
1665 				return 0;
1666 			if (option < 0 || option > 7)
1667 				break;
1668 			*journal_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE,
1669 							    option);
1670 			break;
1671 		case Opt_noauto_da_alloc:
1672 			set_opt(sbi->s_mount_opt,NO_AUTO_DA_ALLOC);
1673 			break;
1674 		case Opt_auto_da_alloc:
1675 			if (args[0].from) {
1676 				if (match_int(&args[0], &option))
1677 					return 0;
1678 			} else
1679 				option = 1;	/* No argument, default to 1 */
1680 			if (option)
1681 				clear_opt(sbi->s_mount_opt, NO_AUTO_DA_ALLOC);
1682 			else
1683 				set_opt(sbi->s_mount_opt,NO_AUTO_DA_ALLOC);
1684 			break;
1685 		case Opt_discard:
1686 			set_opt(sbi->s_mount_opt, DISCARD);
1687 			break;
1688 		case Opt_nodiscard:
1689 			clear_opt(sbi->s_mount_opt, DISCARD);
1690 			break;
1691 		case Opt_dioread_nolock:
1692 			set_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
1693 			break;
1694 		case Opt_dioread_lock:
1695 			clear_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
1696 			break;
1697 		default:
1698 			ext4_msg(sb, KERN_ERR,
1699 			       "Unrecognized mount option \"%s\" "
1700 			       "or missing value", p);
1701 			return 0;
1702 		}
1703 	}
1704 #ifdef CONFIG_QUOTA
1705 	if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
1706 		if (test_opt(sb, USRQUOTA) && sbi->s_qf_names[USRQUOTA])
1707 			clear_opt(sbi->s_mount_opt, USRQUOTA);
1708 
1709 		if (test_opt(sb, GRPQUOTA) && sbi->s_qf_names[GRPQUOTA])
1710 			clear_opt(sbi->s_mount_opt, GRPQUOTA);
1711 
1712 		if (test_opt(sb, GRPQUOTA) || test_opt(sb, USRQUOTA)) {
1713 			ext4_msg(sb, KERN_ERR, "old and new quota "
1714 					"format mixing");
1715 			return 0;
1716 		}
1717 
1718 		if (!sbi->s_jquota_fmt) {
1719 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1720 					"not specified");
1721 			return 0;
1722 		}
1723 	} else {
1724 		if (sbi->s_jquota_fmt) {
1725 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1726 					"specified with no journaling "
1727 					"enabled");
1728 			return 0;
1729 		}
1730 	}
1731 #endif
1732 	return 1;
1733 }
1734 
1735 static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
1736 			    int read_only)
1737 {
1738 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1739 	int res = 0;
1740 
1741 	if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
1742 		ext4_msg(sb, KERN_ERR, "revision level too high, "
1743 			 "forcing read-only mode");
1744 		res = MS_RDONLY;
1745 	}
1746 	if (read_only)
1747 		return res;
1748 	if (!(sbi->s_mount_state & EXT4_VALID_FS))
1749 		ext4_msg(sb, KERN_WARNING, "warning: mounting unchecked fs, "
1750 			 "running e2fsck is recommended");
1751 	else if ((sbi->s_mount_state & EXT4_ERROR_FS))
1752 		ext4_msg(sb, KERN_WARNING,
1753 			 "warning: mounting fs with errors, "
1754 			 "running e2fsck is recommended");
1755 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
1756 		 le16_to_cpu(es->s_mnt_count) >=
1757 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
1758 		ext4_msg(sb, KERN_WARNING,
1759 			 "warning: maximal mount count reached, "
1760 			 "running e2fsck is recommended");
1761 	else if (le32_to_cpu(es->s_checkinterval) &&
1762 		(le32_to_cpu(es->s_lastcheck) +
1763 			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
1764 		ext4_msg(sb, KERN_WARNING,
1765 			 "warning: checktime reached, "
1766 			 "running e2fsck is recommended");
1767 	if (!sbi->s_journal)
1768 		es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1769 	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
1770 		es->s_max_mnt_count = cpu_to_le16(EXT4_DFL_MAX_MNT_COUNT);
1771 	le16_add_cpu(&es->s_mnt_count, 1);
1772 	es->s_mtime = cpu_to_le32(get_seconds());
1773 	ext4_update_dynamic_rev(sb);
1774 	if (sbi->s_journal)
1775 		EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
1776 
1777 	ext4_commit_super(sb, 1);
1778 	if (test_opt(sb, DEBUG))
1779 		printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, "
1780 				"bpg=%lu, ipg=%lu, mo=%04x]\n",
1781 			sb->s_blocksize,
1782 			sbi->s_groups_count,
1783 			EXT4_BLOCKS_PER_GROUP(sb),
1784 			EXT4_INODES_PER_GROUP(sb),
1785 			sbi->s_mount_opt);
1786 
1787 	return res;
1788 }
1789 
1790 static int ext4_fill_flex_info(struct super_block *sb)
1791 {
1792 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1793 	struct ext4_group_desc *gdp = NULL;
1794 	ext4_group_t flex_group_count;
1795 	ext4_group_t flex_group;
1796 	int groups_per_flex = 0;
1797 	size_t size;
1798 	int i;
1799 
1800 	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
1801 	groups_per_flex = 1 << sbi->s_log_groups_per_flex;
1802 
1803 	if (groups_per_flex < 2) {
1804 		sbi->s_log_groups_per_flex = 0;
1805 		return 1;
1806 	}
1807 
1808 	/* We allocate both existing and potentially added groups */
1809 	flex_group_count = ((sbi->s_groups_count + groups_per_flex - 1) +
1810 			((le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) + 1) <<
1811 			      EXT4_DESC_PER_BLOCK_BITS(sb))) / groups_per_flex;
1812 	size = flex_group_count * sizeof(struct flex_groups);
1813 	sbi->s_flex_groups = kzalloc(size, GFP_KERNEL);
1814 	if (sbi->s_flex_groups == NULL) {
1815 		sbi->s_flex_groups = vmalloc(size);
1816 		if (sbi->s_flex_groups)
1817 			memset(sbi->s_flex_groups, 0, size);
1818 	}
1819 	if (sbi->s_flex_groups == NULL) {
1820 		ext4_msg(sb, KERN_ERR, "not enough memory for "
1821 				"%u flex groups", flex_group_count);
1822 		goto failed;
1823 	}
1824 
1825 	for (i = 0; i < sbi->s_groups_count; i++) {
1826 		gdp = ext4_get_group_desc(sb, i, NULL);
1827 
1828 		flex_group = ext4_flex_group(sbi, i);
1829 		atomic_add(ext4_free_inodes_count(sb, gdp),
1830 			   &sbi->s_flex_groups[flex_group].free_inodes);
1831 		atomic_add(ext4_free_blks_count(sb, gdp),
1832 			   &sbi->s_flex_groups[flex_group].free_blocks);
1833 		atomic_add(ext4_used_dirs_count(sb, gdp),
1834 			   &sbi->s_flex_groups[flex_group].used_dirs);
1835 	}
1836 
1837 	return 1;
1838 failed:
1839 	return 0;
1840 }
1841 
1842 __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
1843 			    struct ext4_group_desc *gdp)
1844 {
1845 	__u16 crc = 0;
1846 
1847 	if (sbi->s_es->s_feature_ro_compat &
1848 	    cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
1849 		int offset = offsetof(struct ext4_group_desc, bg_checksum);
1850 		__le32 le_group = cpu_to_le32(block_group);
1851 
1852 		crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
1853 		crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
1854 		crc = crc16(crc, (__u8 *)gdp, offset);
1855 		offset += sizeof(gdp->bg_checksum); /* skip checksum */
1856 		/* for checksum of struct ext4_group_desc do the rest...*/
1857 		if ((sbi->s_es->s_feature_incompat &
1858 		     cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) &&
1859 		    offset < le16_to_cpu(sbi->s_es->s_desc_size))
1860 			crc = crc16(crc, (__u8 *)gdp + offset,
1861 				    le16_to_cpu(sbi->s_es->s_desc_size) -
1862 					offset);
1863 	}
1864 
1865 	return cpu_to_le16(crc);
1866 }
1867 
1868 int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 block_group,
1869 				struct ext4_group_desc *gdp)
1870 {
1871 	if ((sbi->s_es->s_feature_ro_compat &
1872 	     cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) &&
1873 	    (gdp->bg_checksum != ext4_group_desc_csum(sbi, block_group, gdp)))
1874 		return 0;
1875 
1876 	return 1;
1877 }
1878 
1879 /* Called at mount-time, super-block is locked */
1880 static int ext4_check_descriptors(struct super_block *sb)
1881 {
1882 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1883 	ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
1884 	ext4_fsblk_t last_block;
1885 	ext4_fsblk_t block_bitmap;
1886 	ext4_fsblk_t inode_bitmap;
1887 	ext4_fsblk_t inode_table;
1888 	int flexbg_flag = 0;
1889 	ext4_group_t i;
1890 
1891 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
1892 		flexbg_flag = 1;
1893 
1894 	ext4_debug("Checking group descriptors");
1895 
1896 	for (i = 0; i < sbi->s_groups_count; i++) {
1897 		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1898 
1899 		if (i == sbi->s_groups_count - 1 || flexbg_flag)
1900 			last_block = ext4_blocks_count(sbi->s_es) - 1;
1901 		else
1902 			last_block = first_block +
1903 				(EXT4_BLOCKS_PER_GROUP(sb) - 1);
1904 
1905 		block_bitmap = ext4_block_bitmap(sb, gdp);
1906 		if (block_bitmap < first_block || block_bitmap > last_block) {
1907 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
1908 			       "Block bitmap for group %u not in group "
1909 			       "(block %llu)!", i, block_bitmap);
1910 			return 0;
1911 		}
1912 		inode_bitmap = ext4_inode_bitmap(sb, gdp);
1913 		if (inode_bitmap < first_block || inode_bitmap > last_block) {
1914 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
1915 			       "Inode bitmap for group %u not in group "
1916 			       "(block %llu)!", i, inode_bitmap);
1917 			return 0;
1918 		}
1919 		inode_table = ext4_inode_table(sb, gdp);
1920 		if (inode_table < first_block ||
1921 		    inode_table + sbi->s_itb_per_group - 1 > last_block) {
1922 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
1923 			       "Inode table for group %u not in group "
1924 			       "(block %llu)!", i, inode_table);
1925 			return 0;
1926 		}
1927 		ext4_lock_group(sb, i);
1928 		if (!ext4_group_desc_csum_verify(sbi, i, gdp)) {
1929 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
1930 				 "Checksum for group %u failed (%u!=%u)",
1931 				 i, le16_to_cpu(ext4_group_desc_csum(sbi, i,
1932 				     gdp)), le16_to_cpu(gdp->bg_checksum));
1933 			if (!(sb->s_flags & MS_RDONLY)) {
1934 				ext4_unlock_group(sb, i);
1935 				return 0;
1936 			}
1937 		}
1938 		ext4_unlock_group(sb, i);
1939 		if (!flexbg_flag)
1940 			first_block += EXT4_BLOCKS_PER_GROUP(sb);
1941 	}
1942 
1943 	ext4_free_blocks_count_set(sbi->s_es, ext4_count_free_blocks(sb));
1944 	sbi->s_es->s_free_inodes_count =cpu_to_le32(ext4_count_free_inodes(sb));
1945 	return 1;
1946 }
1947 
1948 /* ext4_orphan_cleanup() walks a singly-linked list of inodes (starting at
1949  * the superblock) which were deleted from all directories, but held open by
1950  * a process at the time of a crash.  We walk the list and try to delete these
1951  * inodes at recovery time (only with a read-write filesystem).
1952  *
1953  * In order to keep the orphan inode chain consistent during traversal (in
1954  * case of crash during recovery), we link each inode into the superblock
1955  * orphan list_head and handle it the same way as an inode deletion during
1956  * normal operation (which journals the operations for us).
1957  *
1958  * We only do an iget() and an iput() on each inode, which is very safe if we
1959  * accidentally point at an in-use or already deleted inode.  The worst that
1960  * can happen in this case is that we get a "bit already cleared" message from
1961  * ext4_free_inode().  The only reason we would point at a wrong inode is if
1962  * e2fsck was run on this filesystem, and it must have already done the orphan
1963  * inode cleanup for us, so we can safely abort without any further action.
1964  */
1965 static void ext4_orphan_cleanup(struct super_block *sb,
1966 				struct ext4_super_block *es)
1967 {
1968 	unsigned int s_flags = sb->s_flags;
1969 	int nr_orphans = 0, nr_truncates = 0;
1970 #ifdef CONFIG_QUOTA
1971 	int i;
1972 #endif
1973 	if (!es->s_last_orphan) {
1974 		jbd_debug(4, "no orphan inodes to clean up\n");
1975 		return;
1976 	}
1977 
1978 	if (bdev_read_only(sb->s_bdev)) {
1979 		ext4_msg(sb, KERN_ERR, "write access "
1980 			"unavailable, skipping orphan cleanup");
1981 		return;
1982 	}
1983 
1984 	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
1985 		if (es->s_last_orphan)
1986 			jbd_debug(1, "Errors on filesystem, "
1987 				  "clearing orphan list.\n");
1988 		es->s_last_orphan = 0;
1989 		jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
1990 		return;
1991 	}
1992 
1993 	if (s_flags & MS_RDONLY) {
1994 		ext4_msg(sb, KERN_INFO, "orphan cleanup on readonly fs");
1995 		sb->s_flags &= ~MS_RDONLY;
1996 	}
1997 #ifdef CONFIG_QUOTA
1998 	/* Needed for iput() to work correctly and not trash data */
1999 	sb->s_flags |= MS_ACTIVE;
2000 	/* Turn on quotas so that they are updated correctly */
2001 	for (i = 0; i < MAXQUOTAS; i++) {
2002 		if (EXT4_SB(sb)->s_qf_names[i]) {
2003 			int ret = ext4_quota_on_mount(sb, i);
2004 			if (ret < 0)
2005 				ext4_msg(sb, KERN_ERR,
2006 					"Cannot turn on journaled "
2007 					"quota: error %d", ret);
2008 		}
2009 	}
2010 #endif
2011 
2012 	while (es->s_last_orphan) {
2013 		struct inode *inode;
2014 
2015 		inode = ext4_orphan_get(sb, le32_to_cpu(es->s_last_orphan));
2016 		if (IS_ERR(inode)) {
2017 			es->s_last_orphan = 0;
2018 			break;
2019 		}
2020 
2021 		list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
2022 		dquot_initialize(inode);
2023 		if (inode->i_nlink) {
2024 			ext4_msg(sb, KERN_DEBUG,
2025 				"%s: truncating inode %lu to %lld bytes",
2026 				__func__, inode->i_ino, inode->i_size);
2027 			jbd_debug(2, "truncating inode %lu to %lld bytes\n",
2028 				  inode->i_ino, inode->i_size);
2029 			ext4_truncate(inode);
2030 			nr_truncates++;
2031 		} else {
2032 			ext4_msg(sb, KERN_DEBUG,
2033 				"%s: deleting unreferenced inode %lu",
2034 				__func__, inode->i_ino);
2035 			jbd_debug(2, "deleting unreferenced inode %lu\n",
2036 				  inode->i_ino);
2037 			nr_orphans++;
2038 		}
2039 		iput(inode);  /* The delete magic happens here! */
2040 	}
2041 
2042 #define PLURAL(x) (x), ((x) == 1) ? "" : "s"
2043 
2044 	if (nr_orphans)
2045 		ext4_msg(sb, KERN_INFO, "%d orphan inode%s deleted",
2046 		       PLURAL(nr_orphans));
2047 	if (nr_truncates)
2048 		ext4_msg(sb, KERN_INFO, "%d truncate%s cleaned up",
2049 		       PLURAL(nr_truncates));
2050 #ifdef CONFIG_QUOTA
2051 	/* Turn quotas off */
2052 	for (i = 0; i < MAXQUOTAS; i++) {
2053 		if (sb_dqopt(sb)->files[i])
2054 			vfs_quota_off(sb, i, 0);
2055 	}
2056 #endif
2057 	sb->s_flags = s_flags; /* Restore MS_RDONLY status */
2058 }
2059 
2060 /*
2061  * Maximal extent format file size.
2062  * Resulting logical blkno at s_maxbytes must fit in our on-disk
2063  * extent format containers, within a sector_t, and within i_blocks
2064  * in the vfs.  ext4 inode has 48 bits of i_block in fsblock units,
2065  * so that won't be a limiting factor.
2066  *
2067  * Note, this does *not* consider any metadata overhead for vfs i_blocks.
2068  */
2069 static loff_t ext4_max_size(int blkbits, int has_huge_files)
2070 {
2071 	loff_t res;
2072 	loff_t upper_limit = MAX_LFS_FILESIZE;
2073 
2074 	/* small i_blocks in vfs inode? */
2075 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2076 		/*
2077 		 * CONFIG_LBDAF is not enabled implies the inode
2078 		 * i_block represent total blocks in 512 bytes
2079 		 * 32 == size of vfs inode i_blocks * 8
2080 		 */
2081 		upper_limit = (1LL << 32) - 1;
2082 
2083 		/* total blocks in file system block size */
2084 		upper_limit >>= (blkbits - 9);
2085 		upper_limit <<= blkbits;
2086 	}
2087 
2088 	/* 32-bit extent-start container, ee_block */
2089 	res = 1LL << 32;
2090 	res <<= blkbits;
2091 	res -= 1;
2092 
2093 	/* Sanity check against vm- & vfs- imposed limits */
2094 	if (res > upper_limit)
2095 		res = upper_limit;
2096 
2097 	return res;
2098 }
2099 
2100 /*
2101  * Maximal bitmap file size.  There is a direct, and {,double-,triple-}indirect
2102  * block limit, and also a limit of (2^48 - 1) 512-byte sectors in i_blocks.
2103  * We need to be 1 filesystem block less than the 2^48 sector limit.
2104  */
2105 static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
2106 {
2107 	loff_t res = EXT4_NDIR_BLOCKS;
2108 	int meta_blocks;
2109 	loff_t upper_limit;
2110 	/* This is calculated to be the largest file size for a dense, block
2111 	 * mapped file such that the file's total number of 512-byte sectors,
2112 	 * including data and all indirect blocks, does not exceed (2^48 - 1).
2113 	 *
2114 	 * __u32 i_blocks_lo and _u16 i_blocks_high represent the total
2115 	 * number of 512-byte sectors of the file.
2116 	 */
2117 
2118 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2119 		/*
2120 		 * !has_huge_files or CONFIG_LBDAF not enabled implies that
2121 		 * the inode i_block field represents total file blocks in
2122 		 * 2^32 512-byte sectors == size of vfs inode i_blocks * 8
2123 		 */
2124 		upper_limit = (1LL << 32) - 1;
2125 
2126 		/* total blocks in file system block size */
2127 		upper_limit >>= (bits - 9);
2128 
2129 	} else {
2130 		/*
2131 		 * We use 48 bit ext4_inode i_blocks
2132 		 * With EXT4_HUGE_FILE_FL set the i_blocks
2133 		 * represent total number of blocks in
2134 		 * file system block size
2135 		 */
2136 		upper_limit = (1LL << 48) - 1;
2137 
2138 	}
2139 
2140 	/* indirect blocks */
2141 	meta_blocks = 1;
2142 	/* double indirect blocks */
2143 	meta_blocks += 1 + (1LL << (bits-2));
2144 	/* tripple indirect blocks */
2145 	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
2146 
2147 	upper_limit -= meta_blocks;
2148 	upper_limit <<= bits;
2149 
2150 	res += 1LL << (bits-2);
2151 	res += 1LL << (2*(bits-2));
2152 	res += 1LL << (3*(bits-2));
2153 	res <<= bits;
2154 	if (res > upper_limit)
2155 		res = upper_limit;
2156 
2157 	if (res > MAX_LFS_FILESIZE)
2158 		res = MAX_LFS_FILESIZE;
2159 
2160 	return res;
2161 }
2162 
2163 static ext4_fsblk_t descriptor_loc(struct super_block *sb,
2164 				   ext4_fsblk_t logical_sb_block, int nr)
2165 {
2166 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2167 	ext4_group_t bg, first_meta_bg;
2168 	int has_super = 0;
2169 
2170 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
2171 
2172 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
2173 	    nr < first_meta_bg)
2174 		return logical_sb_block + nr + 1;
2175 	bg = sbi->s_desc_per_block * nr;
2176 	if (ext4_bg_has_super(sb, bg))
2177 		has_super = 1;
2178 
2179 	return (has_super + ext4_group_first_block_no(sb, bg));
2180 }
2181 
2182 /**
2183  * ext4_get_stripe_size: Get the stripe size.
2184  * @sbi: In memory super block info
2185  *
2186  * If we have specified it via mount option, then
2187  * use the mount option value. If the value specified at mount time is
2188  * greater than the blocks per group use the super block value.
2189  * If the super block value is greater than blocks per group return 0.
2190  * Allocator needs it be less than blocks per group.
2191  *
2192  */
2193 static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi)
2194 {
2195 	unsigned long stride = le16_to_cpu(sbi->s_es->s_raid_stride);
2196 	unsigned long stripe_width =
2197 			le32_to_cpu(sbi->s_es->s_raid_stripe_width);
2198 
2199 	if (sbi->s_stripe && sbi->s_stripe <= sbi->s_blocks_per_group)
2200 		return sbi->s_stripe;
2201 
2202 	if (stripe_width <= sbi->s_blocks_per_group)
2203 		return stripe_width;
2204 
2205 	if (stride <= sbi->s_blocks_per_group)
2206 		return stride;
2207 
2208 	return 0;
2209 }
2210 
2211 /* sysfs supprt */
2212 
2213 struct ext4_attr {
2214 	struct attribute attr;
2215 	ssize_t (*show)(struct ext4_attr *, struct ext4_sb_info *, char *);
2216 	ssize_t (*store)(struct ext4_attr *, struct ext4_sb_info *,
2217 			 const char *, size_t);
2218 	int offset;
2219 };
2220 
2221 static int parse_strtoul(const char *buf,
2222 		unsigned long max, unsigned long *value)
2223 {
2224 	char *endp;
2225 
2226 	*value = simple_strtoul(skip_spaces(buf), &endp, 0);
2227 	endp = skip_spaces(endp);
2228 	if (*endp || *value > max)
2229 		return -EINVAL;
2230 
2231 	return 0;
2232 }
2233 
2234 static ssize_t delayed_allocation_blocks_show(struct ext4_attr *a,
2235 					      struct ext4_sb_info *sbi,
2236 					      char *buf)
2237 {
2238 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2239 			(s64) percpu_counter_sum(&sbi->s_dirtyblocks_counter));
2240 }
2241 
2242 static ssize_t session_write_kbytes_show(struct ext4_attr *a,
2243 					 struct ext4_sb_info *sbi, char *buf)
2244 {
2245 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
2246 
2247 	return snprintf(buf, PAGE_SIZE, "%lu\n",
2248 			(part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
2249 			 sbi->s_sectors_written_start) >> 1);
2250 }
2251 
2252 static ssize_t lifetime_write_kbytes_show(struct ext4_attr *a,
2253 					  struct ext4_sb_info *sbi, char *buf)
2254 {
2255 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
2256 
2257 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2258 			(unsigned long long)(sbi->s_kbytes_written +
2259 			((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
2260 			  EXT4_SB(sb)->s_sectors_written_start) >> 1)));
2261 }
2262 
2263 static ssize_t inode_readahead_blks_store(struct ext4_attr *a,
2264 					  struct ext4_sb_info *sbi,
2265 					  const char *buf, size_t count)
2266 {
2267 	unsigned long t;
2268 
2269 	if (parse_strtoul(buf, 0x40000000, &t))
2270 		return -EINVAL;
2271 
2272 	if (!is_power_of_2(t))
2273 		return -EINVAL;
2274 
2275 	sbi->s_inode_readahead_blks = t;
2276 	return count;
2277 }
2278 
2279 static ssize_t sbi_ui_show(struct ext4_attr *a,
2280 			   struct ext4_sb_info *sbi, char *buf)
2281 {
2282 	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
2283 
2284 	return snprintf(buf, PAGE_SIZE, "%u\n", *ui);
2285 }
2286 
2287 static ssize_t sbi_ui_store(struct ext4_attr *a,
2288 			    struct ext4_sb_info *sbi,
2289 			    const char *buf, size_t count)
2290 {
2291 	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
2292 	unsigned long t;
2293 
2294 	if (parse_strtoul(buf, 0xffffffff, &t))
2295 		return -EINVAL;
2296 	*ui = t;
2297 	return count;
2298 }
2299 
2300 #define EXT4_ATTR_OFFSET(_name,_mode,_show,_store,_elname) \
2301 static struct ext4_attr ext4_attr_##_name = {			\
2302 	.attr = {.name = __stringify(_name), .mode = _mode },	\
2303 	.show	= _show,					\
2304 	.store	= _store,					\
2305 	.offset = offsetof(struct ext4_sb_info, _elname),	\
2306 }
2307 #define EXT4_ATTR(name, mode, show, store) \
2308 static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store)
2309 
2310 #define EXT4_RO_ATTR(name) EXT4_ATTR(name, 0444, name##_show, NULL)
2311 #define EXT4_RW_ATTR(name) EXT4_ATTR(name, 0644, name##_show, name##_store)
2312 #define EXT4_RW_ATTR_SBI_UI(name, elname)	\
2313 	EXT4_ATTR_OFFSET(name, 0644, sbi_ui_show, sbi_ui_store, elname)
2314 #define ATTR_LIST(name) &ext4_attr_##name.attr
2315 
2316 EXT4_RO_ATTR(delayed_allocation_blocks);
2317 EXT4_RO_ATTR(session_write_kbytes);
2318 EXT4_RO_ATTR(lifetime_write_kbytes);
2319 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, sbi_ui_show,
2320 		 inode_readahead_blks_store, s_inode_readahead_blks);
2321 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
2322 EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
2323 EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
2324 EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
2325 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
2326 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
2327 EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
2328 EXT4_RW_ATTR_SBI_UI(max_writeback_mb_bump, s_max_writeback_mb_bump);
2329 
2330 static struct attribute *ext4_attrs[] = {
2331 	ATTR_LIST(delayed_allocation_blocks),
2332 	ATTR_LIST(session_write_kbytes),
2333 	ATTR_LIST(lifetime_write_kbytes),
2334 	ATTR_LIST(inode_readahead_blks),
2335 	ATTR_LIST(inode_goal),
2336 	ATTR_LIST(mb_stats),
2337 	ATTR_LIST(mb_max_to_scan),
2338 	ATTR_LIST(mb_min_to_scan),
2339 	ATTR_LIST(mb_order2_req),
2340 	ATTR_LIST(mb_stream_req),
2341 	ATTR_LIST(mb_group_prealloc),
2342 	ATTR_LIST(max_writeback_mb_bump),
2343 	NULL,
2344 };
2345 
2346 static ssize_t ext4_attr_show(struct kobject *kobj,
2347 			      struct attribute *attr, char *buf)
2348 {
2349 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2350 						s_kobj);
2351 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
2352 
2353 	return a->show ? a->show(a, sbi, buf) : 0;
2354 }
2355 
2356 static ssize_t ext4_attr_store(struct kobject *kobj,
2357 			       struct attribute *attr,
2358 			       const char *buf, size_t len)
2359 {
2360 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2361 						s_kobj);
2362 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
2363 
2364 	return a->store ? a->store(a, sbi, buf, len) : 0;
2365 }
2366 
2367 static void ext4_sb_release(struct kobject *kobj)
2368 {
2369 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2370 						s_kobj);
2371 	complete(&sbi->s_kobj_unregister);
2372 }
2373 
2374 
2375 static const struct sysfs_ops ext4_attr_ops = {
2376 	.show	= ext4_attr_show,
2377 	.store	= ext4_attr_store,
2378 };
2379 
2380 static struct kobj_type ext4_ktype = {
2381 	.default_attrs	= ext4_attrs,
2382 	.sysfs_ops	= &ext4_attr_ops,
2383 	.release	= ext4_sb_release,
2384 };
2385 
2386 /*
2387  * Check whether this filesystem can be mounted based on
2388  * the features present and the RDONLY/RDWR mount requested.
2389  * Returns 1 if this filesystem can be mounted as requested,
2390  * 0 if it cannot be.
2391  */
2392 static int ext4_feature_set_ok(struct super_block *sb, int readonly)
2393 {
2394 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT4_FEATURE_INCOMPAT_SUPP)) {
2395 		ext4_msg(sb, KERN_ERR,
2396 			"Couldn't mount because of "
2397 			"unsupported optional features (%x)",
2398 			(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_incompat) &
2399 			~EXT4_FEATURE_INCOMPAT_SUPP));
2400 		return 0;
2401 	}
2402 
2403 	if (readonly)
2404 		return 1;
2405 
2406 	/* Check that feature set is OK for a read-write mount */
2407 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT4_FEATURE_RO_COMPAT_SUPP)) {
2408 		ext4_msg(sb, KERN_ERR, "couldn't mount RDWR because of "
2409 			 "unsupported optional features (%x)",
2410 			 (le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_ro_compat) &
2411 				~EXT4_FEATURE_RO_COMPAT_SUPP));
2412 		return 0;
2413 	}
2414 	/*
2415 	 * Large file size enabled file system can only be mounted
2416 	 * read-write on 32-bit systems if kernel is built with CONFIG_LBDAF
2417 	 */
2418 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
2419 		if (sizeof(blkcnt_t) < sizeof(u64)) {
2420 			ext4_msg(sb, KERN_ERR, "Filesystem with huge files "
2421 				 "cannot be mounted RDWR without "
2422 				 "CONFIG_LBDAF");
2423 			return 0;
2424 		}
2425 	}
2426 	return 1;
2427 }
2428 
2429 static int ext4_fill_super(struct super_block *sb, void *data, int silent)
2430 				__releases(kernel_lock)
2431 				__acquires(kernel_lock)
2432 {
2433 	struct buffer_head *bh;
2434 	struct ext4_super_block *es = NULL;
2435 	struct ext4_sb_info *sbi;
2436 	ext4_fsblk_t block;
2437 	ext4_fsblk_t sb_block = get_sb_block(&data);
2438 	ext4_fsblk_t logical_sb_block;
2439 	unsigned long offset = 0;
2440 	unsigned long journal_devnum = 0;
2441 	unsigned long def_mount_opts;
2442 	struct inode *root;
2443 	char *cp;
2444 	const char *descr;
2445 	int ret = -EINVAL;
2446 	int blocksize;
2447 	unsigned int db_count;
2448 	unsigned int i;
2449 	int needs_recovery, has_huge_files;
2450 	__u64 blocks_count;
2451 	int err;
2452 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
2453 
2454 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
2455 	if (!sbi)
2456 		return -ENOMEM;
2457 
2458 	sbi->s_blockgroup_lock =
2459 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
2460 	if (!sbi->s_blockgroup_lock) {
2461 		kfree(sbi);
2462 		return -ENOMEM;
2463 	}
2464 	sb->s_fs_info = sbi;
2465 	sbi->s_mount_opt = 0;
2466 	sbi->s_resuid = EXT4_DEF_RESUID;
2467 	sbi->s_resgid = EXT4_DEF_RESGID;
2468 	sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
2469 	sbi->s_sb_block = sb_block;
2470 	sbi->s_sectors_written_start = part_stat_read(sb->s_bdev->bd_part,
2471 						      sectors[1]);
2472 
2473 	unlock_kernel();
2474 
2475 	/* Cleanup superblock name */
2476 	for (cp = sb->s_id; (cp = strchr(cp, '/'));)
2477 		*cp = '!';
2478 
2479 	blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
2480 	if (!blocksize) {
2481 		ext4_msg(sb, KERN_ERR, "unable to set blocksize");
2482 		goto out_fail;
2483 	}
2484 
2485 	/*
2486 	 * The ext4 superblock will not be buffer aligned for other than 1kB
2487 	 * block sizes.  We need to calculate the offset from buffer start.
2488 	 */
2489 	if (blocksize != EXT4_MIN_BLOCK_SIZE) {
2490 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
2491 		offset = do_div(logical_sb_block, blocksize);
2492 	} else {
2493 		logical_sb_block = sb_block;
2494 	}
2495 
2496 	if (!(bh = sb_bread(sb, logical_sb_block))) {
2497 		ext4_msg(sb, KERN_ERR, "unable to read superblock");
2498 		goto out_fail;
2499 	}
2500 	/*
2501 	 * Note: s_es must be initialized as soon as possible because
2502 	 *       some ext4 macro-instructions depend on its value
2503 	 */
2504 	es = (struct ext4_super_block *) (((char *)bh->b_data) + offset);
2505 	sbi->s_es = es;
2506 	sb->s_magic = le16_to_cpu(es->s_magic);
2507 	if (sb->s_magic != EXT4_SUPER_MAGIC)
2508 		goto cantfind_ext4;
2509 	sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
2510 
2511 	/* Set defaults before we parse the mount options */
2512 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
2513 	if (def_mount_opts & EXT4_DEFM_DEBUG)
2514 		set_opt(sbi->s_mount_opt, DEBUG);
2515 	if (def_mount_opts & EXT4_DEFM_BSDGROUPS) {
2516 		ext4_msg(sb, KERN_WARNING, deprecated_msg, "bsdgroups",
2517 			"2.6.38");
2518 		set_opt(sbi->s_mount_opt, GRPID);
2519 	}
2520 	if (def_mount_opts & EXT4_DEFM_UID16)
2521 		set_opt(sbi->s_mount_opt, NO_UID32);
2522 #ifdef CONFIG_EXT4_FS_XATTR
2523 	if (def_mount_opts & EXT4_DEFM_XATTR_USER)
2524 		set_opt(sbi->s_mount_opt, XATTR_USER);
2525 #endif
2526 #ifdef CONFIG_EXT4_FS_POSIX_ACL
2527 	if (def_mount_opts & EXT4_DEFM_ACL)
2528 		set_opt(sbi->s_mount_opt, POSIX_ACL);
2529 #endif
2530 	if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA)
2531 		set_opt(sbi->s_mount_opt, JOURNAL_DATA);
2532 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_ORDERED)
2533 		set_opt(sbi->s_mount_opt, ORDERED_DATA);
2534 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_WBACK)
2535 		set_opt(sbi->s_mount_opt, WRITEBACK_DATA);
2536 
2537 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_PANIC)
2538 		set_opt(sbi->s_mount_opt, ERRORS_PANIC);
2539 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_CONTINUE)
2540 		set_opt(sbi->s_mount_opt, ERRORS_CONT);
2541 	else
2542 		set_opt(sbi->s_mount_opt, ERRORS_RO);
2543 
2544 	sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
2545 	sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
2546 	sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ;
2547 	sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;
2548 	sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;
2549 
2550 	set_opt(sbi->s_mount_opt, BARRIER);
2551 
2552 	/*
2553 	 * enable delayed allocation by default
2554 	 * Use -o nodelalloc to turn it off
2555 	 */
2556 	if (!IS_EXT3_SB(sb))
2557 		set_opt(sbi->s_mount_opt, DELALLOC);
2558 
2559 	if (!parse_options((char *) data, sb, &journal_devnum,
2560 			   &journal_ioprio, NULL, 0))
2561 		goto failed_mount;
2562 
2563 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
2564 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
2565 
2566 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
2567 	    (EXT4_HAS_COMPAT_FEATURE(sb, ~0U) ||
2568 	     EXT4_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
2569 	     EXT4_HAS_INCOMPAT_FEATURE(sb, ~0U)))
2570 		ext4_msg(sb, KERN_WARNING,
2571 		       "feature flags set on rev 0 fs, "
2572 		       "running e2fsck is recommended");
2573 
2574 	/*
2575 	 * Check feature flags regardless of the revision level, since we
2576 	 * previously didn't change the revision level when setting the flags,
2577 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
2578 	 */
2579 	if (!ext4_feature_set_ok(sb, (sb->s_flags & MS_RDONLY)))
2580 		goto failed_mount;
2581 
2582 	blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
2583 
2584 	if (blocksize < EXT4_MIN_BLOCK_SIZE ||
2585 	    blocksize > EXT4_MAX_BLOCK_SIZE) {
2586 		ext4_msg(sb, KERN_ERR,
2587 		       "Unsupported filesystem blocksize %d", blocksize);
2588 		goto failed_mount;
2589 	}
2590 
2591 	if (sb->s_blocksize != blocksize) {
2592 		/* Validate the filesystem blocksize */
2593 		if (!sb_set_blocksize(sb, blocksize)) {
2594 			ext4_msg(sb, KERN_ERR, "bad block size %d",
2595 					blocksize);
2596 			goto failed_mount;
2597 		}
2598 
2599 		brelse(bh);
2600 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
2601 		offset = do_div(logical_sb_block, blocksize);
2602 		bh = sb_bread(sb, logical_sb_block);
2603 		if (!bh) {
2604 			ext4_msg(sb, KERN_ERR,
2605 			       "Can't read superblock on 2nd try");
2606 			goto failed_mount;
2607 		}
2608 		es = (struct ext4_super_block *)(((char *)bh->b_data) + offset);
2609 		sbi->s_es = es;
2610 		if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
2611 			ext4_msg(sb, KERN_ERR,
2612 			       "Magic mismatch, very weird!");
2613 			goto failed_mount;
2614 		}
2615 	}
2616 
2617 	has_huge_files = EXT4_HAS_RO_COMPAT_FEATURE(sb,
2618 				EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
2619 	sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits,
2620 						      has_huge_files);
2621 	sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits, has_huge_files);
2622 
2623 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) {
2624 		sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE;
2625 		sbi->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
2626 	} else {
2627 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
2628 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
2629 		if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
2630 		    (!is_power_of_2(sbi->s_inode_size)) ||
2631 		    (sbi->s_inode_size > blocksize)) {
2632 			ext4_msg(sb, KERN_ERR,
2633 			       "unsupported inode size: %d",
2634 			       sbi->s_inode_size);
2635 			goto failed_mount;
2636 		}
2637 		if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE)
2638 			sb->s_time_gran = 1 << (EXT4_EPOCH_BITS - 2);
2639 	}
2640 
2641 	sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
2642 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT)) {
2643 		if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT ||
2644 		    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
2645 		    !is_power_of_2(sbi->s_desc_size)) {
2646 			ext4_msg(sb, KERN_ERR,
2647 			       "unsupported descriptor size %lu",
2648 			       sbi->s_desc_size);
2649 			goto failed_mount;
2650 		}
2651 	} else
2652 		sbi->s_desc_size = EXT4_MIN_DESC_SIZE;
2653 
2654 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
2655 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
2656 	if (EXT4_INODE_SIZE(sb) == 0 || EXT4_INODES_PER_GROUP(sb) == 0)
2657 		goto cantfind_ext4;
2658 
2659 	sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
2660 	if (sbi->s_inodes_per_block == 0)
2661 		goto cantfind_ext4;
2662 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
2663 					sbi->s_inodes_per_block;
2664 	sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
2665 	sbi->s_sbh = bh;
2666 	sbi->s_mount_state = le16_to_cpu(es->s_state);
2667 	sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
2668 	sbi->s_desc_per_block_bits = ilog2(EXT4_DESC_PER_BLOCK(sb));
2669 
2670 	for (i = 0; i < 4; i++)
2671 		sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
2672 	sbi->s_def_hash_version = es->s_def_hash_version;
2673 	i = le32_to_cpu(es->s_flags);
2674 	if (i & EXT2_FLAGS_UNSIGNED_HASH)
2675 		sbi->s_hash_unsigned = 3;
2676 	else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) {
2677 #ifdef __CHAR_UNSIGNED__
2678 		es->s_flags |= cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH);
2679 		sbi->s_hash_unsigned = 3;
2680 #else
2681 		es->s_flags |= cpu_to_le32(EXT2_FLAGS_SIGNED_HASH);
2682 #endif
2683 		sb->s_dirt = 1;
2684 	}
2685 
2686 	if (sbi->s_blocks_per_group > blocksize * 8) {
2687 		ext4_msg(sb, KERN_ERR,
2688 		       "#blocks per group too big: %lu",
2689 		       sbi->s_blocks_per_group);
2690 		goto failed_mount;
2691 	}
2692 	if (sbi->s_inodes_per_group > blocksize * 8) {
2693 		ext4_msg(sb, KERN_ERR,
2694 		       "#inodes per group too big: %lu",
2695 		       sbi->s_inodes_per_group);
2696 		goto failed_mount;
2697 	}
2698 
2699 	/*
2700 	 * Test whether we have more sectors than will fit in sector_t,
2701 	 * and whether the max offset is addressable by the page cache.
2702 	 */
2703 	if ((ext4_blocks_count(es) >
2704 	     (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) ||
2705 	    (ext4_blocks_count(es) >
2706 	     (pgoff_t)(~0ULL) >> (PAGE_CACHE_SHIFT - sb->s_blocksize_bits))) {
2707 		ext4_msg(sb, KERN_ERR, "filesystem"
2708 			 " too large to mount safely on this system");
2709 		if (sizeof(sector_t) < 8)
2710 			ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled");
2711 		ret = -EFBIG;
2712 		goto failed_mount;
2713 	}
2714 
2715 	if (EXT4_BLOCKS_PER_GROUP(sb) == 0)
2716 		goto cantfind_ext4;
2717 
2718 	/* check blocks count against device size */
2719 	blocks_count = sb->s_bdev->bd_inode->i_size >> sb->s_blocksize_bits;
2720 	if (blocks_count && ext4_blocks_count(es) > blocks_count) {
2721 		ext4_msg(sb, KERN_WARNING, "bad geometry: block count %llu "
2722 		       "exceeds size of device (%llu blocks)",
2723 		       ext4_blocks_count(es), blocks_count);
2724 		goto failed_mount;
2725 	}
2726 
2727 	/*
2728 	 * It makes no sense for the first data block to be beyond the end
2729 	 * of the filesystem.
2730 	 */
2731 	if (le32_to_cpu(es->s_first_data_block) >= ext4_blocks_count(es)) {
2732                 ext4_msg(sb, KERN_WARNING, "bad geometry: first data"
2733 			 "block %u is beyond end of filesystem (%llu)",
2734 			 le32_to_cpu(es->s_first_data_block),
2735 			 ext4_blocks_count(es));
2736 		goto failed_mount;
2737 	}
2738 	blocks_count = (ext4_blocks_count(es) -
2739 			le32_to_cpu(es->s_first_data_block) +
2740 			EXT4_BLOCKS_PER_GROUP(sb) - 1);
2741 	do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
2742 	if (blocks_count > ((uint64_t)1<<32) - EXT4_DESC_PER_BLOCK(sb)) {
2743 		ext4_msg(sb, KERN_WARNING, "groups count too large: %u "
2744 		       "(block count %llu, first data block %u, "
2745 		       "blocks per group %lu)", sbi->s_groups_count,
2746 		       ext4_blocks_count(es),
2747 		       le32_to_cpu(es->s_first_data_block),
2748 		       EXT4_BLOCKS_PER_GROUP(sb));
2749 		goto failed_mount;
2750 	}
2751 	sbi->s_groups_count = blocks_count;
2752 	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
2753 			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
2754 	db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
2755 		   EXT4_DESC_PER_BLOCK(sb);
2756 	sbi->s_group_desc = kmalloc(db_count * sizeof(struct buffer_head *),
2757 				    GFP_KERNEL);
2758 	if (sbi->s_group_desc == NULL) {
2759 		ext4_msg(sb, KERN_ERR, "not enough memory");
2760 		goto failed_mount;
2761 	}
2762 
2763 #ifdef CONFIG_PROC_FS
2764 	if (ext4_proc_root)
2765 		sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
2766 #endif
2767 
2768 	bgl_lock_init(sbi->s_blockgroup_lock);
2769 
2770 	for (i = 0; i < db_count; i++) {
2771 		block = descriptor_loc(sb, logical_sb_block, i);
2772 		sbi->s_group_desc[i] = sb_bread(sb, block);
2773 		if (!sbi->s_group_desc[i]) {
2774 			ext4_msg(sb, KERN_ERR,
2775 			       "can't read group descriptor %d", i);
2776 			db_count = i;
2777 			goto failed_mount2;
2778 		}
2779 	}
2780 	if (!ext4_check_descriptors(sb)) {
2781 		ext4_msg(sb, KERN_ERR, "group descriptors corrupted!");
2782 		goto failed_mount2;
2783 	}
2784 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
2785 		if (!ext4_fill_flex_info(sb)) {
2786 			ext4_msg(sb, KERN_ERR,
2787 			       "unable to initialize "
2788 			       "flex_bg meta info!");
2789 			goto failed_mount2;
2790 		}
2791 
2792 	sbi->s_gdb_count = db_count;
2793 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
2794 	spin_lock_init(&sbi->s_next_gen_lock);
2795 
2796 	err = percpu_counter_init(&sbi->s_freeblocks_counter,
2797 			ext4_count_free_blocks(sb));
2798 	if (!err) {
2799 		err = percpu_counter_init(&sbi->s_freeinodes_counter,
2800 				ext4_count_free_inodes(sb));
2801 	}
2802 	if (!err) {
2803 		err = percpu_counter_init(&sbi->s_dirs_counter,
2804 				ext4_count_dirs(sb));
2805 	}
2806 	if (!err) {
2807 		err = percpu_counter_init(&sbi->s_dirtyblocks_counter, 0);
2808 	}
2809 	if (err) {
2810 		ext4_msg(sb, KERN_ERR, "insufficient memory");
2811 		goto failed_mount3;
2812 	}
2813 
2814 	sbi->s_stripe = ext4_get_stripe_size(sbi);
2815 	sbi->s_max_writeback_mb_bump = 128;
2816 
2817 	/*
2818 	 * set up enough so that it can read an inode
2819 	 */
2820 	if (!test_opt(sb, NOLOAD) &&
2821 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL))
2822 		sb->s_op = &ext4_sops;
2823 	else
2824 		sb->s_op = &ext4_nojournal_sops;
2825 	sb->s_export_op = &ext4_export_ops;
2826 	sb->s_xattr = ext4_xattr_handlers;
2827 #ifdef CONFIG_QUOTA
2828 	sb->s_qcop = &ext4_qctl_operations;
2829 	sb->dq_op = &ext4_quota_operations;
2830 #endif
2831 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
2832 	mutex_init(&sbi->s_orphan_lock);
2833 	mutex_init(&sbi->s_resize_lock);
2834 
2835 	sb->s_root = NULL;
2836 
2837 	needs_recovery = (es->s_last_orphan != 0 ||
2838 			  EXT4_HAS_INCOMPAT_FEATURE(sb,
2839 				    EXT4_FEATURE_INCOMPAT_RECOVER));
2840 
2841 	/*
2842 	 * The first inode we look at is the journal inode.  Don't try
2843 	 * root first: it may be modified in the journal!
2844 	 */
2845 	if (!test_opt(sb, NOLOAD) &&
2846 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
2847 		if (ext4_load_journal(sb, es, journal_devnum))
2848 			goto failed_mount3;
2849 	} else if (test_opt(sb, NOLOAD) && !(sb->s_flags & MS_RDONLY) &&
2850 	      EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
2851 		ext4_msg(sb, KERN_ERR, "required journal recovery "
2852 		       "suppressed and not mounted read-only");
2853 		goto failed_mount_wq;
2854 	} else {
2855 		clear_opt(sbi->s_mount_opt, DATA_FLAGS);
2856 		set_opt(sbi->s_mount_opt, WRITEBACK_DATA);
2857 		sbi->s_journal = NULL;
2858 		needs_recovery = 0;
2859 		goto no_journal;
2860 	}
2861 
2862 	if (ext4_blocks_count(es) > 0xffffffffULL &&
2863 	    !jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
2864 				       JBD2_FEATURE_INCOMPAT_64BIT)) {
2865 		ext4_msg(sb, KERN_ERR, "Failed to set 64-bit journal feature");
2866 		goto failed_mount_wq;
2867 	}
2868 
2869 	if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
2870 		jbd2_journal_set_features(sbi->s_journal,
2871 				JBD2_FEATURE_COMPAT_CHECKSUM, 0,
2872 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
2873 	} else if (test_opt(sb, JOURNAL_CHECKSUM)) {
2874 		jbd2_journal_set_features(sbi->s_journal,
2875 				JBD2_FEATURE_COMPAT_CHECKSUM, 0, 0);
2876 		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
2877 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
2878 	} else {
2879 		jbd2_journal_clear_features(sbi->s_journal,
2880 				JBD2_FEATURE_COMPAT_CHECKSUM, 0,
2881 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
2882 	}
2883 
2884 	/* We have now updated the journal if required, so we can
2885 	 * validate the data journaling mode. */
2886 	switch (test_opt(sb, DATA_FLAGS)) {
2887 	case 0:
2888 		/* No mode set, assume a default based on the journal
2889 		 * capabilities: ORDERED_DATA if the journal can
2890 		 * cope, else JOURNAL_DATA
2891 		 */
2892 		if (jbd2_journal_check_available_features
2893 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE))
2894 			set_opt(sbi->s_mount_opt, ORDERED_DATA);
2895 		else
2896 			set_opt(sbi->s_mount_opt, JOURNAL_DATA);
2897 		break;
2898 
2899 	case EXT4_MOUNT_ORDERED_DATA:
2900 	case EXT4_MOUNT_WRITEBACK_DATA:
2901 		if (!jbd2_journal_check_available_features
2902 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
2903 			ext4_msg(sb, KERN_ERR, "Journal does not support "
2904 			       "requested data journaling mode");
2905 			goto failed_mount_wq;
2906 		}
2907 	default:
2908 		break;
2909 	}
2910 	set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
2911 
2912 no_journal:
2913 	if (test_opt(sb, NOBH)) {
2914 		if (!(test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)) {
2915 			ext4_msg(sb, KERN_WARNING, "Ignoring nobh option - "
2916 				"its supported only with writeback mode");
2917 			clear_opt(sbi->s_mount_opt, NOBH);
2918 		}
2919 		if (test_opt(sb, DIOREAD_NOLOCK)) {
2920 			ext4_msg(sb, KERN_WARNING, "dioread_nolock option is "
2921 				"not supported with nobh mode");
2922 			goto failed_mount_wq;
2923 		}
2924 	}
2925 	EXT4_SB(sb)->dio_unwritten_wq = create_workqueue("ext4-dio-unwritten");
2926 	if (!EXT4_SB(sb)->dio_unwritten_wq) {
2927 		printk(KERN_ERR "EXT4-fs: failed to create DIO workqueue\n");
2928 		goto failed_mount_wq;
2929 	}
2930 
2931 	/*
2932 	 * The jbd2_journal_load will have done any necessary log recovery,
2933 	 * so we can safely mount the rest of the filesystem now.
2934 	 */
2935 
2936 	root = ext4_iget(sb, EXT4_ROOT_INO);
2937 	if (IS_ERR(root)) {
2938 		ext4_msg(sb, KERN_ERR, "get root inode failed");
2939 		ret = PTR_ERR(root);
2940 		goto failed_mount4;
2941 	}
2942 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
2943 		iput(root);
2944 		ext4_msg(sb, KERN_ERR, "corrupt root inode, run e2fsck");
2945 		goto failed_mount4;
2946 	}
2947 	sb->s_root = d_alloc_root(root);
2948 	if (!sb->s_root) {
2949 		ext4_msg(sb, KERN_ERR, "get root dentry failed");
2950 		iput(root);
2951 		ret = -ENOMEM;
2952 		goto failed_mount4;
2953 	}
2954 
2955 	ext4_setup_super(sb, es, sb->s_flags & MS_RDONLY);
2956 
2957 	/* determine the minimum size of new large inodes, if present */
2958 	if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
2959 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
2960 						     EXT4_GOOD_OLD_INODE_SIZE;
2961 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
2962 				       EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE)) {
2963 			if (sbi->s_want_extra_isize <
2964 			    le16_to_cpu(es->s_want_extra_isize))
2965 				sbi->s_want_extra_isize =
2966 					le16_to_cpu(es->s_want_extra_isize);
2967 			if (sbi->s_want_extra_isize <
2968 			    le16_to_cpu(es->s_min_extra_isize))
2969 				sbi->s_want_extra_isize =
2970 					le16_to_cpu(es->s_min_extra_isize);
2971 		}
2972 	}
2973 	/* Check if enough inode space is available */
2974 	if (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize >
2975 							sbi->s_inode_size) {
2976 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
2977 						       EXT4_GOOD_OLD_INODE_SIZE;
2978 		ext4_msg(sb, KERN_INFO, "required extra inode space not"
2979 			 "available");
2980 	}
2981 
2982 	if (test_opt(sb, DELALLOC) &&
2983 	    (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)) {
2984 		ext4_msg(sb, KERN_WARNING, "Ignoring delalloc option - "
2985 			 "requested data journaling mode");
2986 		clear_opt(sbi->s_mount_opt, DELALLOC);
2987 	}
2988 	if (test_opt(sb, DIOREAD_NOLOCK)) {
2989 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
2990 			ext4_msg(sb, KERN_WARNING, "Ignoring dioread_nolock "
2991 				"option - requested data journaling mode");
2992 			clear_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
2993 		}
2994 		if (sb->s_blocksize < PAGE_SIZE) {
2995 			ext4_msg(sb, KERN_WARNING, "Ignoring dioread_nolock "
2996 				"option - block size is too small");
2997 			clear_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
2998 		}
2999 	}
3000 
3001 	err = ext4_setup_system_zone(sb);
3002 	if (err) {
3003 		ext4_msg(sb, KERN_ERR, "failed to initialize system "
3004 			 "zone (%d)\n", err);
3005 		goto failed_mount4;
3006 	}
3007 
3008 	ext4_ext_init(sb);
3009 	err = ext4_mb_init(sb, needs_recovery);
3010 	if (err) {
3011 		ext4_msg(sb, KERN_ERR, "failed to initalize mballoc (%d)",
3012 			 err);
3013 		goto failed_mount4;
3014 	}
3015 
3016 	sbi->s_kobj.kset = ext4_kset;
3017 	init_completion(&sbi->s_kobj_unregister);
3018 	err = kobject_init_and_add(&sbi->s_kobj, &ext4_ktype, NULL,
3019 				   "%s", sb->s_id);
3020 	if (err) {
3021 		ext4_mb_release(sb);
3022 		ext4_ext_release(sb);
3023 		goto failed_mount4;
3024 	};
3025 
3026 	EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
3027 	ext4_orphan_cleanup(sb, es);
3028 	EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
3029 	if (needs_recovery) {
3030 		ext4_msg(sb, KERN_INFO, "recovery complete");
3031 		ext4_mark_recovery_complete(sb, es);
3032 	}
3033 	if (EXT4_SB(sb)->s_journal) {
3034 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
3035 			descr = " journalled data mode";
3036 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
3037 			descr = " ordered data mode";
3038 		else
3039 			descr = " writeback data mode";
3040 	} else
3041 		descr = "out journal";
3042 
3043 	ext4_msg(sb, KERN_INFO, "mounted filesystem with%s", descr);
3044 
3045 	lock_kernel();
3046 	return 0;
3047 
3048 cantfind_ext4:
3049 	if (!silent)
3050 		ext4_msg(sb, KERN_ERR, "VFS: Can't find ext4 filesystem");
3051 	goto failed_mount;
3052 
3053 failed_mount4:
3054 	ext4_msg(sb, KERN_ERR, "mount failed");
3055 	destroy_workqueue(EXT4_SB(sb)->dio_unwritten_wq);
3056 failed_mount_wq:
3057 	ext4_release_system_zone(sb);
3058 	if (sbi->s_journal) {
3059 		jbd2_journal_destroy(sbi->s_journal);
3060 		sbi->s_journal = NULL;
3061 	}
3062 failed_mount3:
3063 	if (sbi->s_flex_groups) {
3064 		if (is_vmalloc_addr(sbi->s_flex_groups))
3065 			vfree(sbi->s_flex_groups);
3066 		else
3067 			kfree(sbi->s_flex_groups);
3068 	}
3069 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
3070 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
3071 	percpu_counter_destroy(&sbi->s_dirs_counter);
3072 	percpu_counter_destroy(&sbi->s_dirtyblocks_counter);
3073 failed_mount2:
3074 	for (i = 0; i < db_count; i++)
3075 		brelse(sbi->s_group_desc[i]);
3076 	kfree(sbi->s_group_desc);
3077 failed_mount:
3078 	if (sbi->s_proc) {
3079 		remove_proc_entry(sb->s_id, ext4_proc_root);
3080 	}
3081 #ifdef CONFIG_QUOTA
3082 	for (i = 0; i < MAXQUOTAS; i++)
3083 		kfree(sbi->s_qf_names[i]);
3084 #endif
3085 	ext4_blkdev_remove(sbi);
3086 	brelse(bh);
3087 out_fail:
3088 	sb->s_fs_info = NULL;
3089 	kfree(sbi->s_blockgroup_lock);
3090 	kfree(sbi);
3091 	lock_kernel();
3092 	return ret;
3093 }
3094 
3095 /*
3096  * Setup any per-fs journal parameters now.  We'll do this both on
3097  * initial mount, once the journal has been initialised but before we've
3098  * done any recovery; and again on any subsequent remount.
3099  */
3100 static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
3101 {
3102 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3103 
3104 	journal->j_commit_interval = sbi->s_commit_interval;
3105 	journal->j_min_batch_time = sbi->s_min_batch_time;
3106 	journal->j_max_batch_time = sbi->s_max_batch_time;
3107 
3108 	spin_lock(&journal->j_state_lock);
3109 	if (test_opt(sb, BARRIER))
3110 		journal->j_flags |= JBD2_BARRIER;
3111 	else
3112 		journal->j_flags &= ~JBD2_BARRIER;
3113 	if (test_opt(sb, DATA_ERR_ABORT))
3114 		journal->j_flags |= JBD2_ABORT_ON_SYNCDATA_ERR;
3115 	else
3116 		journal->j_flags &= ~JBD2_ABORT_ON_SYNCDATA_ERR;
3117 	spin_unlock(&journal->j_state_lock);
3118 }
3119 
3120 static journal_t *ext4_get_journal(struct super_block *sb,
3121 				   unsigned int journal_inum)
3122 {
3123 	struct inode *journal_inode;
3124 	journal_t *journal;
3125 
3126 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
3127 
3128 	/* First, test for the existence of a valid inode on disk.  Bad
3129 	 * things happen if we iget() an unused inode, as the subsequent
3130 	 * iput() will try to delete it. */
3131 
3132 	journal_inode = ext4_iget(sb, journal_inum);
3133 	if (IS_ERR(journal_inode)) {
3134 		ext4_msg(sb, KERN_ERR, "no journal found");
3135 		return NULL;
3136 	}
3137 	if (!journal_inode->i_nlink) {
3138 		make_bad_inode(journal_inode);
3139 		iput(journal_inode);
3140 		ext4_msg(sb, KERN_ERR, "journal inode is deleted");
3141 		return NULL;
3142 	}
3143 
3144 	jbd_debug(2, "Journal inode found at %p: %lld bytes\n",
3145 		  journal_inode, journal_inode->i_size);
3146 	if (!S_ISREG(journal_inode->i_mode)) {
3147 		ext4_msg(sb, KERN_ERR, "invalid journal inode");
3148 		iput(journal_inode);
3149 		return NULL;
3150 	}
3151 
3152 	journal = jbd2_journal_init_inode(journal_inode);
3153 	if (!journal) {
3154 		ext4_msg(sb, KERN_ERR, "Could not load journal inode");
3155 		iput(journal_inode);
3156 		return NULL;
3157 	}
3158 	journal->j_private = sb;
3159 	ext4_init_journal_params(sb, journal);
3160 	return journal;
3161 }
3162 
3163 static journal_t *ext4_get_dev_journal(struct super_block *sb,
3164 				       dev_t j_dev)
3165 {
3166 	struct buffer_head *bh;
3167 	journal_t *journal;
3168 	ext4_fsblk_t start;
3169 	ext4_fsblk_t len;
3170 	int hblock, blocksize;
3171 	ext4_fsblk_t sb_block;
3172 	unsigned long offset;
3173 	struct ext4_super_block *es;
3174 	struct block_device *bdev;
3175 
3176 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
3177 
3178 	bdev = ext4_blkdev_get(j_dev, sb);
3179 	if (bdev == NULL)
3180 		return NULL;
3181 
3182 	if (bd_claim(bdev, sb)) {
3183 		ext4_msg(sb, KERN_ERR,
3184 			"failed to claim external journal device");
3185 		blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
3186 		return NULL;
3187 	}
3188 
3189 	blocksize = sb->s_blocksize;
3190 	hblock = bdev_logical_block_size(bdev);
3191 	if (blocksize < hblock) {
3192 		ext4_msg(sb, KERN_ERR,
3193 			"blocksize too small for journal device");
3194 		goto out_bdev;
3195 	}
3196 
3197 	sb_block = EXT4_MIN_BLOCK_SIZE / blocksize;
3198 	offset = EXT4_MIN_BLOCK_SIZE % blocksize;
3199 	set_blocksize(bdev, blocksize);
3200 	if (!(bh = __bread(bdev, sb_block, blocksize))) {
3201 		ext4_msg(sb, KERN_ERR, "couldn't read superblock of "
3202 		       "external journal");
3203 		goto out_bdev;
3204 	}
3205 
3206 	es = (struct ext4_super_block *) (((char *)bh->b_data) + offset);
3207 	if ((le16_to_cpu(es->s_magic) != EXT4_SUPER_MAGIC) ||
3208 	    !(le32_to_cpu(es->s_feature_incompat) &
3209 	      EXT4_FEATURE_INCOMPAT_JOURNAL_DEV)) {
3210 		ext4_msg(sb, KERN_ERR, "external journal has "
3211 					"bad superblock");
3212 		brelse(bh);
3213 		goto out_bdev;
3214 	}
3215 
3216 	if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
3217 		ext4_msg(sb, KERN_ERR, "journal UUID does not match");
3218 		brelse(bh);
3219 		goto out_bdev;
3220 	}
3221 
3222 	len = ext4_blocks_count(es);
3223 	start = sb_block + 1;
3224 	brelse(bh);	/* we're done with the superblock */
3225 
3226 	journal = jbd2_journal_init_dev(bdev, sb->s_bdev,
3227 					start, len, blocksize);
3228 	if (!journal) {
3229 		ext4_msg(sb, KERN_ERR, "failed to create device journal");
3230 		goto out_bdev;
3231 	}
3232 	journal->j_private = sb;
3233 	ll_rw_block(READ, 1, &journal->j_sb_buffer);
3234 	wait_on_buffer(journal->j_sb_buffer);
3235 	if (!buffer_uptodate(journal->j_sb_buffer)) {
3236 		ext4_msg(sb, KERN_ERR, "I/O error on journal device");
3237 		goto out_journal;
3238 	}
3239 	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
3240 		ext4_msg(sb, KERN_ERR, "External journal has more than one "
3241 					"user (unsupported) - %d",
3242 			be32_to_cpu(journal->j_superblock->s_nr_users));
3243 		goto out_journal;
3244 	}
3245 	EXT4_SB(sb)->journal_bdev = bdev;
3246 	ext4_init_journal_params(sb, journal);
3247 	return journal;
3248 
3249 out_journal:
3250 	jbd2_journal_destroy(journal);
3251 out_bdev:
3252 	ext4_blkdev_put(bdev);
3253 	return NULL;
3254 }
3255 
3256 static int ext4_load_journal(struct super_block *sb,
3257 			     struct ext4_super_block *es,
3258 			     unsigned long journal_devnum)
3259 {
3260 	journal_t *journal;
3261 	unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
3262 	dev_t journal_dev;
3263 	int err = 0;
3264 	int really_read_only;
3265 
3266 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
3267 
3268 	if (journal_devnum &&
3269 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
3270 		ext4_msg(sb, KERN_INFO, "external journal device major/minor "
3271 			"numbers have changed");
3272 		journal_dev = new_decode_dev(journal_devnum);
3273 	} else
3274 		journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));
3275 
3276 	really_read_only = bdev_read_only(sb->s_bdev);
3277 
3278 	/*
3279 	 * Are we loading a blank journal or performing recovery after a
3280 	 * crash?  For recovery, we need to check in advance whether we
3281 	 * can get read-write access to the device.
3282 	 */
3283 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
3284 		if (sb->s_flags & MS_RDONLY) {
3285 			ext4_msg(sb, KERN_INFO, "INFO: recovery "
3286 					"required on readonly filesystem");
3287 			if (really_read_only) {
3288 				ext4_msg(sb, KERN_ERR, "write access "
3289 					"unavailable, cannot proceed");
3290 				return -EROFS;
3291 			}
3292 			ext4_msg(sb, KERN_INFO, "write access will "
3293 			       "be enabled during recovery");
3294 		}
3295 	}
3296 
3297 	if (journal_inum && journal_dev) {
3298 		ext4_msg(sb, KERN_ERR, "filesystem has both journal "
3299 		       "and inode journals!");
3300 		return -EINVAL;
3301 	}
3302 
3303 	if (journal_inum) {
3304 		if (!(journal = ext4_get_journal(sb, journal_inum)))
3305 			return -EINVAL;
3306 	} else {
3307 		if (!(journal = ext4_get_dev_journal(sb, journal_dev)))
3308 			return -EINVAL;
3309 	}
3310 
3311 	if (!(journal->j_flags & JBD2_BARRIER))
3312 		ext4_msg(sb, KERN_INFO, "barriers disabled");
3313 
3314 	if (!really_read_only && test_opt(sb, UPDATE_JOURNAL)) {
3315 		err = jbd2_journal_update_format(journal);
3316 		if (err)  {
3317 			ext4_msg(sb, KERN_ERR, "error updating journal");
3318 			jbd2_journal_destroy(journal);
3319 			return err;
3320 		}
3321 	}
3322 
3323 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER))
3324 		err = jbd2_journal_wipe(journal, !really_read_only);
3325 	if (!err)
3326 		err = jbd2_journal_load(journal);
3327 
3328 	if (err) {
3329 		ext4_msg(sb, KERN_ERR, "error loading journal");
3330 		jbd2_journal_destroy(journal);
3331 		return err;
3332 	}
3333 
3334 	EXT4_SB(sb)->s_journal = journal;
3335 	ext4_clear_journal_err(sb, es);
3336 
3337 	if (journal_devnum &&
3338 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
3339 		es->s_journal_dev = cpu_to_le32(journal_devnum);
3340 
3341 		/* Make sure we flush the recovery flag to disk. */
3342 		ext4_commit_super(sb, 1);
3343 	}
3344 
3345 	return 0;
3346 }
3347 
3348 static int ext4_commit_super(struct super_block *sb, int sync)
3349 {
3350 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
3351 	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
3352 	int error = 0;
3353 
3354 	if (!sbh)
3355 		return error;
3356 	if (buffer_write_io_error(sbh)) {
3357 		/*
3358 		 * Oh, dear.  A previous attempt to write the
3359 		 * superblock failed.  This could happen because the
3360 		 * USB device was yanked out.  Or it could happen to
3361 		 * be a transient write error and maybe the block will
3362 		 * be remapped.  Nothing we can do but to retry the
3363 		 * write and hope for the best.
3364 		 */
3365 		ext4_msg(sb, KERN_ERR, "previous I/O error to "
3366 		       "superblock detected");
3367 		clear_buffer_write_io_error(sbh);
3368 		set_buffer_uptodate(sbh);
3369 	}
3370 	/*
3371 	 * If the file system is mounted read-only, don't update the
3372 	 * superblock write time.  This avoids updating the superblock
3373 	 * write time when we are mounting the root file system
3374 	 * read/only but we need to replay the journal; at that point,
3375 	 * for people who are east of GMT and who make their clock
3376 	 * tick in localtime for Windows bug-for-bug compatibility,
3377 	 * the clock is set in the future, and this will cause e2fsck
3378 	 * to complain and force a full file system check.
3379 	 */
3380 	if (!(sb->s_flags & MS_RDONLY))
3381 		es->s_wtime = cpu_to_le32(get_seconds());
3382 	es->s_kbytes_written =
3383 		cpu_to_le64(EXT4_SB(sb)->s_kbytes_written +
3384 			    ((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
3385 			      EXT4_SB(sb)->s_sectors_written_start) >> 1));
3386 	ext4_free_blocks_count_set(es, percpu_counter_sum_positive(
3387 					&EXT4_SB(sb)->s_freeblocks_counter));
3388 	es->s_free_inodes_count = cpu_to_le32(percpu_counter_sum_positive(
3389 					&EXT4_SB(sb)->s_freeinodes_counter));
3390 	sb->s_dirt = 0;
3391 	BUFFER_TRACE(sbh, "marking dirty");
3392 	mark_buffer_dirty(sbh);
3393 	if (sync) {
3394 		error = sync_dirty_buffer(sbh);
3395 		if (error)
3396 			return error;
3397 
3398 		error = buffer_write_io_error(sbh);
3399 		if (error) {
3400 			ext4_msg(sb, KERN_ERR, "I/O error while writing "
3401 			       "superblock");
3402 			clear_buffer_write_io_error(sbh);
3403 			set_buffer_uptodate(sbh);
3404 		}
3405 	}
3406 	return error;
3407 }
3408 
3409 /*
3410  * Have we just finished recovery?  If so, and if we are mounting (or
3411  * remounting) the filesystem readonly, then we will end up with a
3412  * consistent fs on disk.  Record that fact.
3413  */
3414 static void ext4_mark_recovery_complete(struct super_block *sb,
3415 					struct ext4_super_block *es)
3416 {
3417 	journal_t *journal = EXT4_SB(sb)->s_journal;
3418 
3419 	if (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
3420 		BUG_ON(journal != NULL);
3421 		return;
3422 	}
3423 	jbd2_journal_lock_updates(journal);
3424 	if (jbd2_journal_flush(journal) < 0)
3425 		goto out;
3426 
3427 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER) &&
3428 	    sb->s_flags & MS_RDONLY) {
3429 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
3430 		ext4_commit_super(sb, 1);
3431 	}
3432 
3433 out:
3434 	jbd2_journal_unlock_updates(journal);
3435 }
3436 
3437 /*
3438  * If we are mounting (or read-write remounting) a filesystem whose journal
3439  * has recorded an error from a previous lifetime, move that error to the
3440  * main filesystem now.
3441  */
3442 static void ext4_clear_journal_err(struct super_block *sb,
3443 				   struct ext4_super_block *es)
3444 {
3445 	journal_t *journal;
3446 	int j_errno;
3447 	const char *errstr;
3448 
3449 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
3450 
3451 	journal = EXT4_SB(sb)->s_journal;
3452 
3453 	/*
3454 	 * Now check for any error status which may have been recorded in the
3455 	 * journal by a prior ext4_error() or ext4_abort()
3456 	 */
3457 
3458 	j_errno = jbd2_journal_errno(journal);
3459 	if (j_errno) {
3460 		char nbuf[16];
3461 
3462 		errstr = ext4_decode_error(sb, j_errno, nbuf);
3463 		ext4_warning(sb, "Filesystem error recorded "
3464 			     "from previous mount: %s", errstr);
3465 		ext4_warning(sb, "Marking fs in need of filesystem check.");
3466 
3467 		EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
3468 		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
3469 		ext4_commit_super(sb, 1);
3470 
3471 		jbd2_journal_clear_err(journal);
3472 	}
3473 }
3474 
3475 /*
3476  * Force the running and committing transactions to commit,
3477  * and wait on the commit.
3478  */
3479 int ext4_force_commit(struct super_block *sb)
3480 {
3481 	journal_t *journal;
3482 	int ret = 0;
3483 
3484 	if (sb->s_flags & MS_RDONLY)
3485 		return 0;
3486 
3487 	journal = EXT4_SB(sb)->s_journal;
3488 	if (journal)
3489 		ret = ext4_journal_force_commit(journal);
3490 
3491 	return ret;
3492 }
3493 
3494 static void ext4_write_super(struct super_block *sb)
3495 {
3496 	lock_super(sb);
3497 	ext4_commit_super(sb, 1);
3498 	unlock_super(sb);
3499 }
3500 
3501 static int ext4_sync_fs(struct super_block *sb, int wait)
3502 {
3503 	int ret = 0;
3504 	tid_t target;
3505 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3506 
3507 	trace_ext4_sync_fs(sb, wait);
3508 	flush_workqueue(sbi->dio_unwritten_wq);
3509 	if (jbd2_journal_start_commit(sbi->s_journal, &target)) {
3510 		if (wait)
3511 			jbd2_log_wait_commit(sbi->s_journal, target);
3512 	}
3513 	return ret;
3514 }
3515 
3516 /*
3517  * LVM calls this function before a (read-only) snapshot is created.  This
3518  * gives us a chance to flush the journal completely and mark the fs clean.
3519  */
3520 static int ext4_freeze(struct super_block *sb)
3521 {
3522 	int error = 0;
3523 	journal_t *journal;
3524 
3525 	if (sb->s_flags & MS_RDONLY)
3526 		return 0;
3527 
3528 	journal = EXT4_SB(sb)->s_journal;
3529 
3530 	/* Now we set up the journal barrier. */
3531 	jbd2_journal_lock_updates(journal);
3532 
3533 	/*
3534 	 * Don't clear the needs_recovery flag if we failed to flush
3535 	 * the journal.
3536 	 */
3537 	error = jbd2_journal_flush(journal);
3538 	if (error < 0) {
3539 	out:
3540 		jbd2_journal_unlock_updates(journal);
3541 		return error;
3542 	}
3543 
3544 	/* Journal blocked and flushed, clear needs_recovery flag. */
3545 	EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
3546 	error = ext4_commit_super(sb, 1);
3547 	if (error)
3548 		goto out;
3549 	return 0;
3550 }
3551 
3552 /*
3553  * Called by LVM after the snapshot is done.  We need to reset the RECOVER
3554  * flag here, even though the filesystem is not technically dirty yet.
3555  */
3556 static int ext4_unfreeze(struct super_block *sb)
3557 {
3558 	if (sb->s_flags & MS_RDONLY)
3559 		return 0;
3560 
3561 	lock_super(sb);
3562 	/* Reset the needs_recovery flag before the fs is unlocked. */
3563 	EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
3564 	ext4_commit_super(sb, 1);
3565 	unlock_super(sb);
3566 	jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
3567 	return 0;
3568 }
3569 
3570 static int ext4_remount(struct super_block *sb, int *flags, char *data)
3571 {
3572 	struct ext4_super_block *es;
3573 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3574 	ext4_fsblk_t n_blocks_count = 0;
3575 	unsigned long old_sb_flags;
3576 	struct ext4_mount_options old_opts;
3577 	ext4_group_t g;
3578 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
3579 	int err;
3580 #ifdef CONFIG_QUOTA
3581 	int i;
3582 #endif
3583 
3584 	lock_kernel();
3585 
3586 	/* Store the original options */
3587 	lock_super(sb);
3588 	old_sb_flags = sb->s_flags;
3589 	old_opts.s_mount_opt = sbi->s_mount_opt;
3590 	old_opts.s_resuid = sbi->s_resuid;
3591 	old_opts.s_resgid = sbi->s_resgid;
3592 	old_opts.s_commit_interval = sbi->s_commit_interval;
3593 	old_opts.s_min_batch_time = sbi->s_min_batch_time;
3594 	old_opts.s_max_batch_time = sbi->s_max_batch_time;
3595 #ifdef CONFIG_QUOTA
3596 	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
3597 	for (i = 0; i < MAXQUOTAS; i++)
3598 		old_opts.s_qf_names[i] = sbi->s_qf_names[i];
3599 #endif
3600 	if (sbi->s_journal && sbi->s_journal->j_task->io_context)
3601 		journal_ioprio = sbi->s_journal->j_task->io_context->ioprio;
3602 
3603 	/*
3604 	 * Allow the "check" option to be passed as a remount option.
3605 	 */
3606 	if (!parse_options(data, sb, NULL, &journal_ioprio,
3607 			   &n_blocks_count, 1)) {
3608 		err = -EINVAL;
3609 		goto restore_opts;
3610 	}
3611 
3612 	if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
3613 		ext4_abort(sb, __func__, "Abort forced by user");
3614 
3615 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
3616 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
3617 
3618 	es = sbi->s_es;
3619 
3620 	if (sbi->s_journal) {
3621 		ext4_init_journal_params(sb, sbi->s_journal);
3622 		set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
3623 	}
3624 
3625 	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY) ||
3626 		n_blocks_count > ext4_blocks_count(es)) {
3627 		if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) {
3628 			err = -EROFS;
3629 			goto restore_opts;
3630 		}
3631 
3632 		if (*flags & MS_RDONLY) {
3633 			/*
3634 			 * First of all, the unconditional stuff we have to do
3635 			 * to disable replay of the journal when we next remount
3636 			 */
3637 			sb->s_flags |= MS_RDONLY;
3638 
3639 			/*
3640 			 * OK, test if we are remounting a valid rw partition
3641 			 * readonly, and if so set the rdonly flag and then
3642 			 * mark the partition as valid again.
3643 			 */
3644 			if (!(es->s_state & cpu_to_le16(EXT4_VALID_FS)) &&
3645 			    (sbi->s_mount_state & EXT4_VALID_FS))
3646 				es->s_state = cpu_to_le16(sbi->s_mount_state);
3647 
3648 			if (sbi->s_journal)
3649 				ext4_mark_recovery_complete(sb, es);
3650 		} else {
3651 			/* Make sure we can mount this feature set readwrite */
3652 			if (!ext4_feature_set_ok(sb, 0)) {
3653 				err = -EROFS;
3654 				goto restore_opts;
3655 			}
3656 			/*
3657 			 * Make sure the group descriptor checksums
3658 			 * are sane.  If they aren't, refuse to remount r/w.
3659 			 */
3660 			for (g = 0; g < sbi->s_groups_count; g++) {
3661 				struct ext4_group_desc *gdp =
3662 					ext4_get_group_desc(sb, g, NULL);
3663 
3664 				if (!ext4_group_desc_csum_verify(sbi, g, gdp)) {
3665 					ext4_msg(sb, KERN_ERR,
3666 	       "ext4_remount: Checksum for group %u failed (%u!=%u)",
3667 		g, le16_to_cpu(ext4_group_desc_csum(sbi, g, gdp)),
3668 					       le16_to_cpu(gdp->bg_checksum));
3669 					err = -EINVAL;
3670 					goto restore_opts;
3671 				}
3672 			}
3673 
3674 			/*
3675 			 * If we have an unprocessed orphan list hanging
3676 			 * around from a previously readonly bdev mount,
3677 			 * require a full umount/remount for now.
3678 			 */
3679 			if (es->s_last_orphan) {
3680 				ext4_msg(sb, KERN_WARNING, "Couldn't "
3681 				       "remount RDWR because of unprocessed "
3682 				       "orphan inode list.  Please "
3683 				       "umount/remount instead");
3684 				err = -EINVAL;
3685 				goto restore_opts;
3686 			}
3687 
3688 			/*
3689 			 * Mounting a RDONLY partition read-write, so reread
3690 			 * and store the current valid flag.  (It may have
3691 			 * been changed by e2fsck since we originally mounted
3692 			 * the partition.)
3693 			 */
3694 			if (sbi->s_journal)
3695 				ext4_clear_journal_err(sb, es);
3696 			sbi->s_mount_state = le16_to_cpu(es->s_state);
3697 			if ((err = ext4_group_extend(sb, es, n_blocks_count)))
3698 				goto restore_opts;
3699 			if (!ext4_setup_super(sb, es, 0))
3700 				sb->s_flags &= ~MS_RDONLY;
3701 		}
3702 	}
3703 	ext4_setup_system_zone(sb);
3704 	if (sbi->s_journal == NULL)
3705 		ext4_commit_super(sb, 1);
3706 
3707 #ifdef CONFIG_QUOTA
3708 	/* Release old quota file names */
3709 	for (i = 0; i < MAXQUOTAS; i++)
3710 		if (old_opts.s_qf_names[i] &&
3711 		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
3712 			kfree(old_opts.s_qf_names[i]);
3713 #endif
3714 	unlock_super(sb);
3715 	unlock_kernel();
3716 	return 0;
3717 
3718 restore_opts:
3719 	sb->s_flags = old_sb_flags;
3720 	sbi->s_mount_opt = old_opts.s_mount_opt;
3721 	sbi->s_resuid = old_opts.s_resuid;
3722 	sbi->s_resgid = old_opts.s_resgid;
3723 	sbi->s_commit_interval = old_opts.s_commit_interval;
3724 	sbi->s_min_batch_time = old_opts.s_min_batch_time;
3725 	sbi->s_max_batch_time = old_opts.s_max_batch_time;
3726 #ifdef CONFIG_QUOTA
3727 	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
3728 	for (i = 0; i < MAXQUOTAS; i++) {
3729 		if (sbi->s_qf_names[i] &&
3730 		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
3731 			kfree(sbi->s_qf_names[i]);
3732 		sbi->s_qf_names[i] = old_opts.s_qf_names[i];
3733 	}
3734 #endif
3735 	unlock_super(sb);
3736 	unlock_kernel();
3737 	return err;
3738 }
3739 
3740 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
3741 {
3742 	struct super_block *sb = dentry->d_sb;
3743 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3744 	struct ext4_super_block *es = sbi->s_es;
3745 	u64 fsid;
3746 
3747 	if (test_opt(sb, MINIX_DF)) {
3748 		sbi->s_overhead_last = 0;
3749 	} else if (sbi->s_blocks_last != ext4_blocks_count(es)) {
3750 		ext4_group_t i, ngroups = ext4_get_groups_count(sb);
3751 		ext4_fsblk_t overhead = 0;
3752 
3753 		/*
3754 		 * Compute the overhead (FS structures).  This is constant
3755 		 * for a given filesystem unless the number of block groups
3756 		 * changes so we cache the previous value until it does.
3757 		 */
3758 
3759 		/*
3760 		 * All of the blocks before first_data_block are
3761 		 * overhead
3762 		 */
3763 		overhead = le32_to_cpu(es->s_first_data_block);
3764 
3765 		/*
3766 		 * Add the overhead attributed to the superblock and
3767 		 * block group descriptors.  If the sparse superblocks
3768 		 * feature is turned on, then not all groups have this.
3769 		 */
3770 		for (i = 0; i < ngroups; i++) {
3771 			overhead += ext4_bg_has_super(sb, i) +
3772 				ext4_bg_num_gdb(sb, i);
3773 			cond_resched();
3774 		}
3775 
3776 		/*
3777 		 * Every block group has an inode bitmap, a block
3778 		 * bitmap, and an inode table.
3779 		 */
3780 		overhead += ngroups * (2 + sbi->s_itb_per_group);
3781 		sbi->s_overhead_last = overhead;
3782 		smp_wmb();
3783 		sbi->s_blocks_last = ext4_blocks_count(es);
3784 	}
3785 
3786 	buf->f_type = EXT4_SUPER_MAGIC;
3787 	buf->f_bsize = sb->s_blocksize;
3788 	buf->f_blocks = ext4_blocks_count(es) - sbi->s_overhead_last;
3789 	buf->f_bfree = percpu_counter_sum_positive(&sbi->s_freeblocks_counter) -
3790 		       percpu_counter_sum_positive(&sbi->s_dirtyblocks_counter);
3791 	buf->f_bavail = buf->f_bfree - ext4_r_blocks_count(es);
3792 	if (buf->f_bfree < ext4_r_blocks_count(es))
3793 		buf->f_bavail = 0;
3794 	buf->f_files = le32_to_cpu(es->s_inodes_count);
3795 	buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter);
3796 	buf->f_namelen = EXT4_NAME_LEN;
3797 	fsid = le64_to_cpup((void *)es->s_uuid) ^
3798 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
3799 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
3800 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
3801 
3802 	return 0;
3803 }
3804 
3805 /* Helper function for writing quotas on sync - we need to start transaction
3806  * before quota file is locked for write. Otherwise the are possible deadlocks:
3807  * Process 1                         Process 2
3808  * ext4_create()                     quota_sync()
3809  *   jbd2_journal_start()                  write_dquot()
3810  *   dquot_initialize()                         down(dqio_mutex)
3811  *     down(dqio_mutex)                    jbd2_journal_start()
3812  *
3813  */
3814 
3815 #ifdef CONFIG_QUOTA
3816 
3817 static inline struct inode *dquot_to_inode(struct dquot *dquot)
3818 {
3819 	return sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
3820 }
3821 
3822 static int ext4_write_dquot(struct dquot *dquot)
3823 {
3824 	int ret, err;
3825 	handle_t *handle;
3826 	struct inode *inode;
3827 
3828 	inode = dquot_to_inode(dquot);
3829 	handle = ext4_journal_start(inode,
3830 				    EXT4_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
3831 	if (IS_ERR(handle))
3832 		return PTR_ERR(handle);
3833 	ret = dquot_commit(dquot);
3834 	err = ext4_journal_stop(handle);
3835 	if (!ret)
3836 		ret = err;
3837 	return ret;
3838 }
3839 
3840 static int ext4_acquire_dquot(struct dquot *dquot)
3841 {
3842 	int ret, err;
3843 	handle_t *handle;
3844 
3845 	handle = ext4_journal_start(dquot_to_inode(dquot),
3846 				    EXT4_QUOTA_INIT_BLOCKS(dquot->dq_sb));
3847 	if (IS_ERR(handle))
3848 		return PTR_ERR(handle);
3849 	ret = dquot_acquire(dquot);
3850 	err = ext4_journal_stop(handle);
3851 	if (!ret)
3852 		ret = err;
3853 	return ret;
3854 }
3855 
3856 static int ext4_release_dquot(struct dquot *dquot)
3857 {
3858 	int ret, err;
3859 	handle_t *handle;
3860 
3861 	handle = ext4_journal_start(dquot_to_inode(dquot),
3862 				    EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
3863 	if (IS_ERR(handle)) {
3864 		/* Release dquot anyway to avoid endless cycle in dqput() */
3865 		dquot_release(dquot);
3866 		return PTR_ERR(handle);
3867 	}
3868 	ret = dquot_release(dquot);
3869 	err = ext4_journal_stop(handle);
3870 	if (!ret)
3871 		ret = err;
3872 	return ret;
3873 }
3874 
3875 static int ext4_mark_dquot_dirty(struct dquot *dquot)
3876 {
3877 	/* Are we journaling quotas? */
3878 	if (EXT4_SB(dquot->dq_sb)->s_qf_names[USRQUOTA] ||
3879 	    EXT4_SB(dquot->dq_sb)->s_qf_names[GRPQUOTA]) {
3880 		dquot_mark_dquot_dirty(dquot);
3881 		return ext4_write_dquot(dquot);
3882 	} else {
3883 		return dquot_mark_dquot_dirty(dquot);
3884 	}
3885 }
3886 
3887 static int ext4_write_info(struct super_block *sb, int type)
3888 {
3889 	int ret, err;
3890 	handle_t *handle;
3891 
3892 	/* Data block + inode block */
3893 	handle = ext4_journal_start(sb->s_root->d_inode, 2);
3894 	if (IS_ERR(handle))
3895 		return PTR_ERR(handle);
3896 	ret = dquot_commit_info(sb, type);
3897 	err = ext4_journal_stop(handle);
3898 	if (!ret)
3899 		ret = err;
3900 	return ret;
3901 }
3902 
3903 /*
3904  * Turn on quotas during mount time - we need to find
3905  * the quota file and such...
3906  */
3907 static int ext4_quota_on_mount(struct super_block *sb, int type)
3908 {
3909 	return vfs_quota_on_mount(sb, EXT4_SB(sb)->s_qf_names[type],
3910 				  EXT4_SB(sb)->s_jquota_fmt, type);
3911 }
3912 
3913 /*
3914  * Standard function to be called on quota_on
3915  */
3916 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
3917 			 char *name, int remount)
3918 {
3919 	int err;
3920 	struct path path;
3921 
3922 	if (!test_opt(sb, QUOTA))
3923 		return -EINVAL;
3924 	/* When remounting, no checks are needed and in fact, name is NULL */
3925 	if (remount)
3926 		return vfs_quota_on(sb, type, format_id, name, remount);
3927 
3928 	err = kern_path(name, LOOKUP_FOLLOW, &path);
3929 	if (err)
3930 		return err;
3931 
3932 	/* Quotafile not on the same filesystem? */
3933 	if (path.mnt->mnt_sb != sb) {
3934 		path_put(&path);
3935 		return -EXDEV;
3936 	}
3937 	/* Journaling quota? */
3938 	if (EXT4_SB(sb)->s_qf_names[type]) {
3939 		/* Quotafile not in fs root? */
3940 		if (path.dentry->d_parent != sb->s_root)
3941 			ext4_msg(sb, KERN_WARNING,
3942 				"Quota file not on filesystem root. "
3943 				"Journaled quota will not work");
3944 	}
3945 
3946 	/*
3947 	 * When we journal data on quota file, we have to flush journal to see
3948 	 * all updates to the file when we bypass pagecache...
3949 	 */
3950 	if (EXT4_SB(sb)->s_journal &&
3951 	    ext4_should_journal_data(path.dentry->d_inode)) {
3952 		/*
3953 		 * We don't need to lock updates but journal_flush() could
3954 		 * otherwise be livelocked...
3955 		 */
3956 		jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
3957 		err = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
3958 		jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
3959 		if (err) {
3960 			path_put(&path);
3961 			return err;
3962 		}
3963 	}
3964 
3965 	err = vfs_quota_on_path(sb, type, format_id, &path);
3966 	path_put(&path);
3967 	return err;
3968 }
3969 
3970 /* Read data from quotafile - avoid pagecache and such because we cannot afford
3971  * acquiring the locks... As quota files are never truncated and quota code
3972  * itself serializes the operations (and noone else should touch the files)
3973  * we don't have to be afraid of races */
3974 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
3975 			       size_t len, loff_t off)
3976 {
3977 	struct inode *inode = sb_dqopt(sb)->files[type];
3978 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
3979 	int err = 0;
3980 	int offset = off & (sb->s_blocksize - 1);
3981 	int tocopy;
3982 	size_t toread;
3983 	struct buffer_head *bh;
3984 	loff_t i_size = i_size_read(inode);
3985 
3986 	if (off > i_size)
3987 		return 0;
3988 	if (off+len > i_size)
3989 		len = i_size-off;
3990 	toread = len;
3991 	while (toread > 0) {
3992 		tocopy = sb->s_blocksize - offset < toread ?
3993 				sb->s_blocksize - offset : toread;
3994 		bh = ext4_bread(NULL, inode, blk, 0, &err);
3995 		if (err)
3996 			return err;
3997 		if (!bh)	/* A hole? */
3998 			memset(data, 0, tocopy);
3999 		else
4000 			memcpy(data, bh->b_data+offset, tocopy);
4001 		brelse(bh);
4002 		offset = 0;
4003 		toread -= tocopy;
4004 		data += tocopy;
4005 		blk++;
4006 	}
4007 	return len;
4008 }
4009 
4010 /* Write to quotafile (we know the transaction is already started and has
4011  * enough credits) */
4012 static ssize_t ext4_quota_write(struct super_block *sb, int type,
4013 				const char *data, size_t len, loff_t off)
4014 {
4015 	struct inode *inode = sb_dqopt(sb)->files[type];
4016 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
4017 	int err = 0;
4018 	int offset = off & (sb->s_blocksize - 1);
4019 	int journal_quota = EXT4_SB(sb)->s_qf_names[type] != NULL;
4020 	struct buffer_head *bh;
4021 	handle_t *handle = journal_current_handle();
4022 
4023 	if (EXT4_SB(sb)->s_journal && !handle) {
4024 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
4025 			" cancelled because transaction is not started",
4026 			(unsigned long long)off, (unsigned long long)len);
4027 		return -EIO;
4028 	}
4029 	/*
4030 	 * Since we account only one data block in transaction credits,
4031 	 * then it is impossible to cross a block boundary.
4032 	 */
4033 	if (sb->s_blocksize - offset < len) {
4034 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
4035 			" cancelled because not block aligned",
4036 			(unsigned long long)off, (unsigned long long)len);
4037 		return -EIO;
4038 	}
4039 
4040 	mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
4041 	bh = ext4_bread(handle, inode, blk, 1, &err);
4042 	if (!bh)
4043 		goto out;
4044 	if (journal_quota) {
4045 		err = ext4_journal_get_write_access(handle, bh);
4046 		if (err) {
4047 			brelse(bh);
4048 			goto out;
4049 		}
4050 	}
4051 	lock_buffer(bh);
4052 	memcpy(bh->b_data+offset, data, len);
4053 	flush_dcache_page(bh->b_page);
4054 	unlock_buffer(bh);
4055 	if (journal_quota)
4056 		err = ext4_handle_dirty_metadata(handle, NULL, bh);
4057 	else {
4058 		/* Always do at least ordered writes for quotas */
4059 		err = ext4_jbd2_file_inode(handle, inode);
4060 		mark_buffer_dirty(bh);
4061 	}
4062 	brelse(bh);
4063 out:
4064 	if (err) {
4065 		mutex_unlock(&inode->i_mutex);
4066 		return err;
4067 	}
4068 	if (inode->i_size < off + len) {
4069 		i_size_write(inode, off + len);
4070 		EXT4_I(inode)->i_disksize = inode->i_size;
4071 	}
4072 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
4073 	ext4_mark_inode_dirty(handle, inode);
4074 	mutex_unlock(&inode->i_mutex);
4075 	return len;
4076 }
4077 
4078 #endif
4079 
4080 static int ext4_get_sb(struct file_system_type *fs_type, int flags,
4081 		       const char *dev_name, void *data, struct vfsmount *mnt)
4082 {
4083 	return get_sb_bdev(fs_type, flags, dev_name, data, ext4_fill_super,mnt);
4084 }
4085 
4086 #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
4087 static struct file_system_type ext2_fs_type = {
4088 	.owner		= THIS_MODULE,
4089 	.name		= "ext2",
4090 	.get_sb		= ext4_get_sb,
4091 	.kill_sb	= kill_block_super,
4092 	.fs_flags	= FS_REQUIRES_DEV,
4093 };
4094 
4095 static inline void register_as_ext2(void)
4096 {
4097 	int err = register_filesystem(&ext2_fs_type);
4098 	if (err)
4099 		printk(KERN_WARNING
4100 		       "EXT4-fs: Unable to register as ext2 (%d)\n", err);
4101 }
4102 
4103 static inline void unregister_as_ext2(void)
4104 {
4105 	unregister_filesystem(&ext2_fs_type);
4106 }
4107 MODULE_ALIAS("ext2");
4108 #else
4109 static inline void register_as_ext2(void) { }
4110 static inline void unregister_as_ext2(void) { }
4111 #endif
4112 
4113 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
4114 static inline void register_as_ext3(void)
4115 {
4116 	int err = register_filesystem(&ext3_fs_type);
4117 	if (err)
4118 		printk(KERN_WARNING
4119 		       "EXT4-fs: Unable to register as ext3 (%d)\n", err);
4120 }
4121 
4122 static inline void unregister_as_ext3(void)
4123 {
4124 	unregister_filesystem(&ext3_fs_type);
4125 }
4126 MODULE_ALIAS("ext3");
4127 #else
4128 static inline void register_as_ext3(void) { }
4129 static inline void unregister_as_ext3(void) { }
4130 #endif
4131 
4132 static struct file_system_type ext4_fs_type = {
4133 	.owner		= THIS_MODULE,
4134 	.name		= "ext4",
4135 	.get_sb		= ext4_get_sb,
4136 	.kill_sb	= kill_block_super,
4137 	.fs_flags	= FS_REQUIRES_DEV,
4138 };
4139 
4140 static int __init init_ext4_fs(void)
4141 {
4142 	int err;
4143 
4144 	err = init_ext4_system_zone();
4145 	if (err)
4146 		return err;
4147 	ext4_kset = kset_create_and_add("ext4", NULL, fs_kobj);
4148 	if (!ext4_kset)
4149 		goto out4;
4150 	ext4_proc_root = proc_mkdir("fs/ext4", NULL);
4151 	err = init_ext4_mballoc();
4152 	if (err)
4153 		goto out3;
4154 
4155 	err = init_ext4_xattr();
4156 	if (err)
4157 		goto out2;
4158 	err = init_inodecache();
4159 	if (err)
4160 		goto out1;
4161 	register_as_ext2();
4162 	register_as_ext3();
4163 	err = register_filesystem(&ext4_fs_type);
4164 	if (err)
4165 		goto out;
4166 	return 0;
4167 out:
4168 	unregister_as_ext2();
4169 	unregister_as_ext3();
4170 	destroy_inodecache();
4171 out1:
4172 	exit_ext4_xattr();
4173 out2:
4174 	exit_ext4_mballoc();
4175 out3:
4176 	remove_proc_entry("fs/ext4", NULL);
4177 	kset_unregister(ext4_kset);
4178 out4:
4179 	exit_ext4_system_zone();
4180 	return err;
4181 }
4182 
4183 static void __exit exit_ext4_fs(void)
4184 {
4185 	unregister_as_ext2();
4186 	unregister_as_ext3();
4187 	unregister_filesystem(&ext4_fs_type);
4188 	destroy_inodecache();
4189 	exit_ext4_xattr();
4190 	exit_ext4_mballoc();
4191 	remove_proc_entry("fs/ext4", NULL);
4192 	kset_unregister(ext4_kset);
4193 	exit_ext4_system_zone();
4194 }
4195 
4196 MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
4197 MODULE_DESCRIPTION("Fourth Extended Filesystem");
4198 MODULE_LICENSE("GPL");
4199 module_init(init_ext4_fs)
4200 module_exit(exit_ext4_fs)
4201