xref: /openbmc/linux/fs/ext4/super.c (revision 81d67439)
1 /*
2  *  linux/fs/ext4/super.c
3  *
4  * Copyright (C) 1992, 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  *
9  *  from
10  *
11  *  linux/fs/minix/inode.c
12  *
13  *  Copyright (C) 1991, 1992  Linus Torvalds
14  *
15  *  Big-endian to little-endian byte-swapping/bitmaps by
16  *        David S. Miller (davem@caip.rutgers.edu), 1995
17  */
18 
19 #include <linux/module.h>
20 #include <linux/string.h>
21 #include <linux/fs.h>
22 #include <linux/time.h>
23 #include <linux/vmalloc.h>
24 #include <linux/jbd2.h>
25 #include <linux/slab.h>
26 #include <linux/init.h>
27 #include <linux/blkdev.h>
28 #include <linux/parser.h>
29 #include <linux/buffer_head.h>
30 #include <linux/exportfs.h>
31 #include <linux/vfs.h>
32 #include <linux/random.h>
33 #include <linux/mount.h>
34 #include <linux/namei.h>
35 #include <linux/quotaops.h>
36 #include <linux/seq_file.h>
37 #include <linux/proc_fs.h>
38 #include <linux/ctype.h>
39 #include <linux/log2.h>
40 #include <linux/crc16.h>
41 #include <linux/cleancache.h>
42 #include <asm/uaccess.h>
43 
44 #include <linux/kthread.h>
45 #include <linux/freezer.h>
46 
47 #include "ext4.h"
48 #include "ext4_jbd2.h"
49 #include "xattr.h"
50 #include "acl.h"
51 #include "mballoc.h"
52 
53 #define CREATE_TRACE_POINTS
54 #include <trace/events/ext4.h>
55 
56 static struct proc_dir_entry *ext4_proc_root;
57 static struct kset *ext4_kset;
58 static struct ext4_lazy_init *ext4_li_info;
59 static struct mutex ext4_li_mtx;
60 static struct ext4_features *ext4_feat;
61 
62 static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
63 			     unsigned long journal_devnum);
64 static int ext4_commit_super(struct super_block *sb, int sync);
65 static void ext4_mark_recovery_complete(struct super_block *sb,
66 					struct ext4_super_block *es);
67 static void ext4_clear_journal_err(struct super_block *sb,
68 				   struct ext4_super_block *es);
69 static int ext4_sync_fs(struct super_block *sb, int wait);
70 static const char *ext4_decode_error(struct super_block *sb, int errno,
71 				     char nbuf[16]);
72 static int ext4_remount(struct super_block *sb, int *flags, char *data);
73 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf);
74 static int ext4_unfreeze(struct super_block *sb);
75 static void ext4_write_super(struct super_block *sb);
76 static int ext4_freeze(struct super_block *sb);
77 static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
78 		       const char *dev_name, void *data);
79 static inline int ext2_feature_set_ok(struct super_block *sb);
80 static inline int ext3_feature_set_ok(struct super_block *sb);
81 static int ext4_feature_set_ok(struct super_block *sb, int readonly);
82 static void ext4_destroy_lazyinit_thread(void);
83 static void ext4_unregister_li_request(struct super_block *sb);
84 static void ext4_clear_request_list(void);
85 
86 #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
87 static struct file_system_type ext2_fs_type = {
88 	.owner		= THIS_MODULE,
89 	.name		= "ext2",
90 	.mount		= ext4_mount,
91 	.kill_sb	= kill_block_super,
92 	.fs_flags	= FS_REQUIRES_DEV,
93 };
94 #define IS_EXT2_SB(sb) ((sb)->s_bdev->bd_holder == &ext2_fs_type)
95 #else
96 #define IS_EXT2_SB(sb) (0)
97 #endif
98 
99 
100 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
101 static struct file_system_type ext3_fs_type = {
102 	.owner		= THIS_MODULE,
103 	.name		= "ext3",
104 	.mount		= ext4_mount,
105 	.kill_sb	= kill_block_super,
106 	.fs_flags	= FS_REQUIRES_DEV,
107 };
108 #define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type)
109 #else
110 #define IS_EXT3_SB(sb) (0)
111 #endif
112 
113 ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
114 			       struct ext4_group_desc *bg)
115 {
116 	return le32_to_cpu(bg->bg_block_bitmap_lo) |
117 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
118 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_block_bitmap_hi) << 32 : 0);
119 }
120 
121 ext4_fsblk_t ext4_inode_bitmap(struct super_block *sb,
122 			       struct ext4_group_desc *bg)
123 {
124 	return le32_to_cpu(bg->bg_inode_bitmap_lo) |
125 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
126 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_bitmap_hi) << 32 : 0);
127 }
128 
129 ext4_fsblk_t ext4_inode_table(struct super_block *sb,
130 			      struct ext4_group_desc *bg)
131 {
132 	return le32_to_cpu(bg->bg_inode_table_lo) |
133 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
134 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_table_hi) << 32 : 0);
135 }
136 
137 __u32 ext4_free_blks_count(struct super_block *sb,
138 			      struct ext4_group_desc *bg)
139 {
140 	return le16_to_cpu(bg->bg_free_blocks_count_lo) |
141 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
142 		 (__u32)le16_to_cpu(bg->bg_free_blocks_count_hi) << 16 : 0);
143 }
144 
145 __u32 ext4_free_inodes_count(struct super_block *sb,
146 			      struct ext4_group_desc *bg)
147 {
148 	return le16_to_cpu(bg->bg_free_inodes_count_lo) |
149 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
150 		 (__u32)le16_to_cpu(bg->bg_free_inodes_count_hi) << 16 : 0);
151 }
152 
153 __u32 ext4_used_dirs_count(struct super_block *sb,
154 			      struct ext4_group_desc *bg)
155 {
156 	return le16_to_cpu(bg->bg_used_dirs_count_lo) |
157 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
158 		 (__u32)le16_to_cpu(bg->bg_used_dirs_count_hi) << 16 : 0);
159 }
160 
161 __u32 ext4_itable_unused_count(struct super_block *sb,
162 			      struct ext4_group_desc *bg)
163 {
164 	return le16_to_cpu(bg->bg_itable_unused_lo) |
165 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
166 		 (__u32)le16_to_cpu(bg->bg_itable_unused_hi) << 16 : 0);
167 }
168 
169 void ext4_block_bitmap_set(struct super_block *sb,
170 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
171 {
172 	bg->bg_block_bitmap_lo = cpu_to_le32((u32)blk);
173 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
174 		bg->bg_block_bitmap_hi = cpu_to_le32(blk >> 32);
175 }
176 
177 void ext4_inode_bitmap_set(struct super_block *sb,
178 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
179 {
180 	bg->bg_inode_bitmap_lo  = cpu_to_le32((u32)blk);
181 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
182 		bg->bg_inode_bitmap_hi = cpu_to_le32(blk >> 32);
183 }
184 
185 void ext4_inode_table_set(struct super_block *sb,
186 			  struct ext4_group_desc *bg, ext4_fsblk_t blk)
187 {
188 	bg->bg_inode_table_lo = cpu_to_le32((u32)blk);
189 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
190 		bg->bg_inode_table_hi = cpu_to_le32(blk >> 32);
191 }
192 
193 void ext4_free_blks_set(struct super_block *sb,
194 			  struct ext4_group_desc *bg, __u32 count)
195 {
196 	bg->bg_free_blocks_count_lo = cpu_to_le16((__u16)count);
197 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
198 		bg->bg_free_blocks_count_hi = cpu_to_le16(count >> 16);
199 }
200 
201 void ext4_free_inodes_set(struct super_block *sb,
202 			  struct ext4_group_desc *bg, __u32 count)
203 {
204 	bg->bg_free_inodes_count_lo = cpu_to_le16((__u16)count);
205 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
206 		bg->bg_free_inodes_count_hi = cpu_to_le16(count >> 16);
207 }
208 
209 void ext4_used_dirs_set(struct super_block *sb,
210 			  struct ext4_group_desc *bg, __u32 count)
211 {
212 	bg->bg_used_dirs_count_lo = cpu_to_le16((__u16)count);
213 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
214 		bg->bg_used_dirs_count_hi = cpu_to_le16(count >> 16);
215 }
216 
217 void ext4_itable_unused_set(struct super_block *sb,
218 			  struct ext4_group_desc *bg, __u32 count)
219 {
220 	bg->bg_itable_unused_lo = cpu_to_le16((__u16)count);
221 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
222 		bg->bg_itable_unused_hi = cpu_to_le16(count >> 16);
223 }
224 
225 
226 /* Just increment the non-pointer handle value */
227 static handle_t *ext4_get_nojournal(void)
228 {
229 	handle_t *handle = current->journal_info;
230 	unsigned long ref_cnt = (unsigned long)handle;
231 
232 	BUG_ON(ref_cnt >= EXT4_NOJOURNAL_MAX_REF_COUNT);
233 
234 	ref_cnt++;
235 	handle = (handle_t *)ref_cnt;
236 
237 	current->journal_info = handle;
238 	return handle;
239 }
240 
241 
242 /* Decrement the non-pointer handle value */
243 static void ext4_put_nojournal(handle_t *handle)
244 {
245 	unsigned long ref_cnt = (unsigned long)handle;
246 
247 	BUG_ON(ref_cnt == 0);
248 
249 	ref_cnt--;
250 	handle = (handle_t *)ref_cnt;
251 
252 	current->journal_info = handle;
253 }
254 
255 /*
256  * Wrappers for jbd2_journal_start/end.
257  *
258  * The only special thing we need to do here is to make sure that all
259  * journal_end calls result in the superblock being marked dirty, so
260  * that sync() will call the filesystem's write_super callback if
261  * appropriate.
262  *
263  * To avoid j_barrier hold in userspace when a user calls freeze(),
264  * ext4 prevents a new handle from being started by s_frozen, which
265  * is in an upper layer.
266  */
267 handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
268 {
269 	journal_t *journal;
270 	handle_t  *handle;
271 
272 	if (sb->s_flags & MS_RDONLY)
273 		return ERR_PTR(-EROFS);
274 
275 	journal = EXT4_SB(sb)->s_journal;
276 	handle = ext4_journal_current_handle();
277 
278 	/*
279 	 * If a handle has been started, it should be allowed to
280 	 * finish, otherwise deadlock could happen between freeze
281 	 * and others(e.g. truncate) due to the restart of the
282 	 * journal handle if the filesystem is forzen and active
283 	 * handles are not stopped.
284 	 */
285 	if (!handle)
286 		vfs_check_frozen(sb, SB_FREEZE_TRANS);
287 
288 	if (!journal)
289 		return ext4_get_nojournal();
290 	/*
291 	 * Special case here: if the journal has aborted behind our
292 	 * backs (eg. EIO in the commit thread), then we still need to
293 	 * take the FS itself readonly cleanly.
294 	 */
295 	if (is_journal_aborted(journal)) {
296 		ext4_abort(sb, "Detected aborted journal");
297 		return ERR_PTR(-EROFS);
298 	}
299 	return jbd2_journal_start(journal, nblocks);
300 }
301 
302 /*
303  * The only special thing we need to do here is to make sure that all
304  * jbd2_journal_stop calls result in the superblock being marked dirty, so
305  * that sync() will call the filesystem's write_super callback if
306  * appropriate.
307  */
308 int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle)
309 {
310 	struct super_block *sb;
311 	int err;
312 	int rc;
313 
314 	if (!ext4_handle_valid(handle)) {
315 		ext4_put_nojournal(handle);
316 		return 0;
317 	}
318 	sb = handle->h_transaction->t_journal->j_private;
319 	err = handle->h_err;
320 	rc = jbd2_journal_stop(handle);
321 
322 	if (!err)
323 		err = rc;
324 	if (err)
325 		__ext4_std_error(sb, where, line, err);
326 	return err;
327 }
328 
329 void ext4_journal_abort_handle(const char *caller, unsigned int line,
330 			       const char *err_fn, struct buffer_head *bh,
331 			       handle_t *handle, int err)
332 {
333 	char nbuf[16];
334 	const char *errstr = ext4_decode_error(NULL, err, nbuf);
335 
336 	BUG_ON(!ext4_handle_valid(handle));
337 
338 	if (bh)
339 		BUFFER_TRACE(bh, "abort");
340 
341 	if (!handle->h_err)
342 		handle->h_err = err;
343 
344 	if (is_handle_aborted(handle))
345 		return;
346 
347 	printk(KERN_ERR "%s:%d: aborting transaction: %s in %s\n",
348 	       caller, line, errstr, err_fn);
349 
350 	jbd2_journal_abort_handle(handle);
351 }
352 
353 static void __save_error_info(struct super_block *sb, const char *func,
354 			    unsigned int line)
355 {
356 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
357 
358 	EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
359 	es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
360 	es->s_last_error_time = cpu_to_le32(get_seconds());
361 	strncpy(es->s_last_error_func, func, sizeof(es->s_last_error_func));
362 	es->s_last_error_line = cpu_to_le32(line);
363 	if (!es->s_first_error_time) {
364 		es->s_first_error_time = es->s_last_error_time;
365 		strncpy(es->s_first_error_func, func,
366 			sizeof(es->s_first_error_func));
367 		es->s_first_error_line = cpu_to_le32(line);
368 		es->s_first_error_ino = es->s_last_error_ino;
369 		es->s_first_error_block = es->s_last_error_block;
370 	}
371 	/*
372 	 * Start the daily error reporting function if it hasn't been
373 	 * started already
374 	 */
375 	if (!es->s_error_count)
376 		mod_timer(&EXT4_SB(sb)->s_err_report, jiffies + 24*60*60*HZ);
377 	es->s_error_count = cpu_to_le32(le32_to_cpu(es->s_error_count) + 1);
378 }
379 
380 static void save_error_info(struct super_block *sb, const char *func,
381 			    unsigned int line)
382 {
383 	__save_error_info(sb, func, line);
384 	ext4_commit_super(sb, 1);
385 }
386 
387 
388 /* Deal with the reporting of failure conditions on a filesystem such as
389  * inconsistencies detected or read IO failures.
390  *
391  * On ext2, we can store the error state of the filesystem in the
392  * superblock.  That is not possible on ext4, because we may have other
393  * write ordering constraints on the superblock which prevent us from
394  * writing it out straight away; and given that the journal is about to
395  * be aborted, we can't rely on the current, or future, transactions to
396  * write out the superblock safely.
397  *
398  * We'll just use the jbd2_journal_abort() error code to record an error in
399  * the journal instead.  On recovery, the journal will complain about
400  * that error until we've noted it down and cleared it.
401  */
402 
403 static void ext4_handle_error(struct super_block *sb)
404 {
405 	if (sb->s_flags & MS_RDONLY)
406 		return;
407 
408 	if (!test_opt(sb, ERRORS_CONT)) {
409 		journal_t *journal = EXT4_SB(sb)->s_journal;
410 
411 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
412 		if (journal)
413 			jbd2_journal_abort(journal, -EIO);
414 	}
415 	if (test_opt(sb, ERRORS_RO)) {
416 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
417 		sb->s_flags |= MS_RDONLY;
418 	}
419 	if (test_opt(sb, ERRORS_PANIC))
420 		panic("EXT4-fs (device %s): panic forced after error\n",
421 			sb->s_id);
422 }
423 
424 void __ext4_error(struct super_block *sb, const char *function,
425 		  unsigned int line, const char *fmt, ...)
426 {
427 	struct va_format vaf;
428 	va_list args;
429 
430 	va_start(args, fmt);
431 	vaf.fmt = fmt;
432 	vaf.va = &args;
433 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: comm %s: %pV\n",
434 	       sb->s_id, function, line, current->comm, &vaf);
435 	va_end(args);
436 
437 	ext4_handle_error(sb);
438 }
439 
440 void ext4_error_inode(struct inode *inode, const char *function,
441 		      unsigned int line, ext4_fsblk_t block,
442 		      const char *fmt, ...)
443 {
444 	va_list args;
445 	struct va_format vaf;
446 	struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
447 
448 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
449 	es->s_last_error_block = cpu_to_le64(block);
450 	save_error_info(inode->i_sb, function, line);
451 	va_start(args, fmt);
452 	vaf.fmt = fmt;
453 	vaf.va = &args;
454 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: inode #%lu: ",
455 	       inode->i_sb->s_id, function, line, inode->i_ino);
456 	if (block)
457 		printk(KERN_CONT "block %llu: ", block);
458 	printk(KERN_CONT "comm %s: %pV\n", current->comm, &vaf);
459 	va_end(args);
460 
461 	ext4_handle_error(inode->i_sb);
462 }
463 
464 void ext4_error_file(struct file *file, const char *function,
465 		     unsigned int line, ext4_fsblk_t block,
466 		     const char *fmt, ...)
467 {
468 	va_list args;
469 	struct va_format vaf;
470 	struct ext4_super_block *es;
471 	struct inode *inode = file->f_dentry->d_inode;
472 	char pathname[80], *path;
473 
474 	es = EXT4_SB(inode->i_sb)->s_es;
475 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
476 	save_error_info(inode->i_sb, function, line);
477 	path = d_path(&(file->f_path), pathname, sizeof(pathname));
478 	if (IS_ERR(path))
479 		path = "(unknown)";
480 	printk(KERN_CRIT
481 	       "EXT4-fs error (device %s): %s:%d: inode #%lu: ",
482 	       inode->i_sb->s_id, function, line, inode->i_ino);
483 	if (block)
484 		printk(KERN_CONT "block %llu: ", block);
485 	va_start(args, fmt);
486 	vaf.fmt = fmt;
487 	vaf.va = &args;
488 	printk(KERN_CONT "comm %s: path %s: %pV\n", current->comm, path, &vaf);
489 	va_end(args);
490 
491 	ext4_handle_error(inode->i_sb);
492 }
493 
494 static const char *ext4_decode_error(struct super_block *sb, int errno,
495 				     char nbuf[16])
496 {
497 	char *errstr = NULL;
498 
499 	switch (errno) {
500 	case -EIO:
501 		errstr = "IO failure";
502 		break;
503 	case -ENOMEM:
504 		errstr = "Out of memory";
505 		break;
506 	case -EROFS:
507 		if (!sb || (EXT4_SB(sb)->s_journal &&
508 			    EXT4_SB(sb)->s_journal->j_flags & JBD2_ABORT))
509 			errstr = "Journal has aborted";
510 		else
511 			errstr = "Readonly filesystem";
512 		break;
513 	default:
514 		/* If the caller passed in an extra buffer for unknown
515 		 * errors, textualise them now.  Else we just return
516 		 * NULL. */
517 		if (nbuf) {
518 			/* Check for truncated error codes... */
519 			if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
520 				errstr = nbuf;
521 		}
522 		break;
523 	}
524 
525 	return errstr;
526 }
527 
528 /* __ext4_std_error decodes expected errors from journaling functions
529  * automatically and invokes the appropriate error response.  */
530 
531 void __ext4_std_error(struct super_block *sb, const char *function,
532 		      unsigned int line, int errno)
533 {
534 	char nbuf[16];
535 	const char *errstr;
536 
537 	/* Special case: if the error is EROFS, and we're not already
538 	 * inside a transaction, then there's really no point in logging
539 	 * an error. */
540 	if (errno == -EROFS && journal_current_handle() == NULL &&
541 	    (sb->s_flags & MS_RDONLY))
542 		return;
543 
544 	errstr = ext4_decode_error(sb, errno, nbuf);
545 	printk(KERN_CRIT "EXT4-fs error (device %s) in %s:%d: %s\n",
546 	       sb->s_id, function, line, errstr);
547 	save_error_info(sb, function, line);
548 
549 	ext4_handle_error(sb);
550 }
551 
552 /*
553  * ext4_abort is a much stronger failure handler than ext4_error.  The
554  * abort function may be used to deal with unrecoverable failures such
555  * as journal IO errors or ENOMEM at a critical moment in log management.
556  *
557  * We unconditionally force the filesystem into an ABORT|READONLY state,
558  * unless the error response on the fs has been set to panic in which
559  * case we take the easy way out and panic immediately.
560  */
561 
562 void __ext4_abort(struct super_block *sb, const char *function,
563 		unsigned int line, const char *fmt, ...)
564 {
565 	va_list args;
566 
567 	save_error_info(sb, function, line);
568 	va_start(args, fmt);
569 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: ", sb->s_id,
570 	       function, line);
571 	vprintk(fmt, args);
572 	printk("\n");
573 	va_end(args);
574 
575 	if ((sb->s_flags & MS_RDONLY) == 0) {
576 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
577 		sb->s_flags |= MS_RDONLY;
578 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
579 		if (EXT4_SB(sb)->s_journal)
580 			jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
581 		save_error_info(sb, function, line);
582 	}
583 	if (test_opt(sb, ERRORS_PANIC))
584 		panic("EXT4-fs panic from previous error\n");
585 }
586 
587 void ext4_msg(struct super_block *sb, const char *prefix, const char *fmt, ...)
588 {
589 	struct va_format vaf;
590 	va_list args;
591 
592 	va_start(args, fmt);
593 	vaf.fmt = fmt;
594 	vaf.va = &args;
595 	printk("%sEXT4-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
596 	va_end(args);
597 }
598 
599 void __ext4_warning(struct super_block *sb, const char *function,
600 		    unsigned int line, const char *fmt, ...)
601 {
602 	struct va_format vaf;
603 	va_list args;
604 
605 	va_start(args, fmt);
606 	vaf.fmt = fmt;
607 	vaf.va = &args;
608 	printk(KERN_WARNING "EXT4-fs warning (device %s): %s:%d: %pV\n",
609 	       sb->s_id, function, line, &vaf);
610 	va_end(args);
611 }
612 
613 void __ext4_grp_locked_error(const char *function, unsigned int line,
614 			     struct super_block *sb, ext4_group_t grp,
615 			     unsigned long ino, ext4_fsblk_t block,
616 			     const char *fmt, ...)
617 __releases(bitlock)
618 __acquires(bitlock)
619 {
620 	struct va_format vaf;
621 	va_list args;
622 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
623 
624 	es->s_last_error_ino = cpu_to_le32(ino);
625 	es->s_last_error_block = cpu_to_le64(block);
626 	__save_error_info(sb, function, line);
627 
628 	va_start(args, fmt);
629 
630 	vaf.fmt = fmt;
631 	vaf.va = &args;
632 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: group %u, ",
633 	       sb->s_id, function, line, grp);
634 	if (ino)
635 		printk(KERN_CONT "inode %lu: ", ino);
636 	if (block)
637 		printk(KERN_CONT "block %llu:", (unsigned long long) block);
638 	printk(KERN_CONT "%pV\n", &vaf);
639 	va_end(args);
640 
641 	if (test_opt(sb, ERRORS_CONT)) {
642 		ext4_commit_super(sb, 0);
643 		return;
644 	}
645 
646 	ext4_unlock_group(sb, grp);
647 	ext4_handle_error(sb);
648 	/*
649 	 * We only get here in the ERRORS_RO case; relocking the group
650 	 * may be dangerous, but nothing bad will happen since the
651 	 * filesystem will have already been marked read/only and the
652 	 * journal has been aborted.  We return 1 as a hint to callers
653 	 * who might what to use the return value from
654 	 * ext4_grp_locked_error() to distinguish between the
655 	 * ERRORS_CONT and ERRORS_RO case, and perhaps return more
656 	 * aggressively from the ext4 function in question, with a
657 	 * more appropriate error code.
658 	 */
659 	ext4_lock_group(sb, grp);
660 	return;
661 }
662 
663 void ext4_update_dynamic_rev(struct super_block *sb)
664 {
665 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
666 
667 	if (le32_to_cpu(es->s_rev_level) > EXT4_GOOD_OLD_REV)
668 		return;
669 
670 	ext4_warning(sb,
671 		     "updating to rev %d because of new feature flag, "
672 		     "running e2fsck is recommended",
673 		     EXT4_DYNAMIC_REV);
674 
675 	es->s_first_ino = cpu_to_le32(EXT4_GOOD_OLD_FIRST_INO);
676 	es->s_inode_size = cpu_to_le16(EXT4_GOOD_OLD_INODE_SIZE);
677 	es->s_rev_level = cpu_to_le32(EXT4_DYNAMIC_REV);
678 	/* leave es->s_feature_*compat flags alone */
679 	/* es->s_uuid will be set by e2fsck if empty */
680 
681 	/*
682 	 * The rest of the superblock fields should be zero, and if not it
683 	 * means they are likely already in use, so leave them alone.  We
684 	 * can leave it up to e2fsck to clean up any inconsistencies there.
685 	 */
686 }
687 
688 /*
689  * Open the external journal device
690  */
691 static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb)
692 {
693 	struct block_device *bdev;
694 	char b[BDEVNAME_SIZE];
695 
696 	bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb);
697 	if (IS_ERR(bdev))
698 		goto fail;
699 	return bdev;
700 
701 fail:
702 	ext4_msg(sb, KERN_ERR, "failed to open journal device %s: %ld",
703 			__bdevname(dev, b), PTR_ERR(bdev));
704 	return NULL;
705 }
706 
707 /*
708  * Release the journal device
709  */
710 static int ext4_blkdev_put(struct block_device *bdev)
711 {
712 	return blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
713 }
714 
715 static int ext4_blkdev_remove(struct ext4_sb_info *sbi)
716 {
717 	struct block_device *bdev;
718 	int ret = -ENODEV;
719 
720 	bdev = sbi->journal_bdev;
721 	if (bdev) {
722 		ret = ext4_blkdev_put(bdev);
723 		sbi->journal_bdev = NULL;
724 	}
725 	return ret;
726 }
727 
728 static inline struct inode *orphan_list_entry(struct list_head *l)
729 {
730 	return &list_entry(l, struct ext4_inode_info, i_orphan)->vfs_inode;
731 }
732 
733 static void dump_orphan_list(struct super_block *sb, struct ext4_sb_info *sbi)
734 {
735 	struct list_head *l;
736 
737 	ext4_msg(sb, KERN_ERR, "sb orphan head is %d",
738 		 le32_to_cpu(sbi->s_es->s_last_orphan));
739 
740 	printk(KERN_ERR "sb_info orphan list:\n");
741 	list_for_each(l, &sbi->s_orphan) {
742 		struct inode *inode = orphan_list_entry(l);
743 		printk(KERN_ERR "  "
744 		       "inode %s:%lu at %p: mode %o, nlink %d, next %d\n",
745 		       inode->i_sb->s_id, inode->i_ino, inode,
746 		       inode->i_mode, inode->i_nlink,
747 		       NEXT_ORPHAN(inode));
748 	}
749 }
750 
751 static void ext4_put_super(struct super_block *sb)
752 {
753 	struct ext4_sb_info *sbi = EXT4_SB(sb);
754 	struct ext4_super_block *es = sbi->s_es;
755 	int i, err;
756 
757 	ext4_unregister_li_request(sb);
758 	dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
759 
760 	flush_workqueue(sbi->dio_unwritten_wq);
761 	destroy_workqueue(sbi->dio_unwritten_wq);
762 
763 	lock_super(sb);
764 	if (sb->s_dirt)
765 		ext4_commit_super(sb, 1);
766 
767 	if (sbi->s_journal) {
768 		err = jbd2_journal_destroy(sbi->s_journal);
769 		sbi->s_journal = NULL;
770 		if (err < 0)
771 			ext4_abort(sb, "Couldn't clean up the journal");
772 	}
773 
774 	del_timer(&sbi->s_err_report);
775 	ext4_release_system_zone(sb);
776 	ext4_mb_release(sb);
777 	ext4_ext_release(sb);
778 	ext4_xattr_put_super(sb);
779 
780 	if (!(sb->s_flags & MS_RDONLY)) {
781 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
782 		es->s_state = cpu_to_le16(sbi->s_mount_state);
783 		ext4_commit_super(sb, 1);
784 	}
785 	if (sbi->s_proc) {
786 		remove_proc_entry(sb->s_id, ext4_proc_root);
787 	}
788 	kobject_del(&sbi->s_kobj);
789 
790 	for (i = 0; i < sbi->s_gdb_count; i++)
791 		brelse(sbi->s_group_desc[i]);
792 	kfree(sbi->s_group_desc);
793 	if (is_vmalloc_addr(sbi->s_flex_groups))
794 		vfree(sbi->s_flex_groups);
795 	else
796 		kfree(sbi->s_flex_groups);
797 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
798 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
799 	percpu_counter_destroy(&sbi->s_dirs_counter);
800 	percpu_counter_destroy(&sbi->s_dirtyblocks_counter);
801 	brelse(sbi->s_sbh);
802 #ifdef CONFIG_QUOTA
803 	for (i = 0; i < MAXQUOTAS; i++)
804 		kfree(sbi->s_qf_names[i]);
805 #endif
806 
807 	/* Debugging code just in case the in-memory inode orphan list
808 	 * isn't empty.  The on-disk one can be non-empty if we've
809 	 * detected an error and taken the fs readonly, but the
810 	 * in-memory list had better be clean by this point. */
811 	if (!list_empty(&sbi->s_orphan))
812 		dump_orphan_list(sb, sbi);
813 	J_ASSERT(list_empty(&sbi->s_orphan));
814 
815 	invalidate_bdev(sb->s_bdev);
816 	if (sbi->journal_bdev && sbi->journal_bdev != sb->s_bdev) {
817 		/*
818 		 * Invalidate the journal device's buffers.  We don't want them
819 		 * floating about in memory - the physical journal device may
820 		 * hotswapped, and it breaks the `ro-after' testing code.
821 		 */
822 		sync_blockdev(sbi->journal_bdev);
823 		invalidate_bdev(sbi->journal_bdev);
824 		ext4_blkdev_remove(sbi);
825 	}
826 	if (sbi->s_mmp_tsk)
827 		kthread_stop(sbi->s_mmp_tsk);
828 	sb->s_fs_info = NULL;
829 	/*
830 	 * Now that we are completely done shutting down the
831 	 * superblock, we need to actually destroy the kobject.
832 	 */
833 	unlock_super(sb);
834 	kobject_put(&sbi->s_kobj);
835 	wait_for_completion(&sbi->s_kobj_unregister);
836 	kfree(sbi->s_blockgroup_lock);
837 	kfree(sbi);
838 }
839 
840 static struct kmem_cache *ext4_inode_cachep;
841 
842 /*
843  * Called inside transaction, so use GFP_NOFS
844  */
845 static struct inode *ext4_alloc_inode(struct super_block *sb)
846 {
847 	struct ext4_inode_info *ei;
848 
849 	ei = kmem_cache_alloc(ext4_inode_cachep, GFP_NOFS);
850 	if (!ei)
851 		return NULL;
852 
853 	ei->vfs_inode.i_version = 1;
854 	ei->vfs_inode.i_data.writeback_index = 0;
855 	memset(&ei->i_cached_extent, 0, sizeof(struct ext4_ext_cache));
856 	INIT_LIST_HEAD(&ei->i_prealloc_list);
857 	spin_lock_init(&ei->i_prealloc_lock);
858 	ei->i_reserved_data_blocks = 0;
859 	ei->i_reserved_meta_blocks = 0;
860 	ei->i_allocated_meta_blocks = 0;
861 	ei->i_da_metadata_calc_len = 0;
862 	spin_lock_init(&(ei->i_block_reservation_lock));
863 #ifdef CONFIG_QUOTA
864 	ei->i_reserved_quota = 0;
865 #endif
866 	ei->jinode = NULL;
867 	INIT_LIST_HEAD(&ei->i_completed_io_list);
868 	spin_lock_init(&ei->i_completed_io_lock);
869 	ei->cur_aio_dio = NULL;
870 	ei->i_sync_tid = 0;
871 	ei->i_datasync_tid = 0;
872 	atomic_set(&ei->i_ioend_count, 0);
873 	atomic_set(&ei->i_aiodio_unwritten, 0);
874 
875 	return &ei->vfs_inode;
876 }
877 
878 static int ext4_drop_inode(struct inode *inode)
879 {
880 	int drop = generic_drop_inode(inode);
881 
882 	trace_ext4_drop_inode(inode, drop);
883 	return drop;
884 }
885 
886 static void ext4_i_callback(struct rcu_head *head)
887 {
888 	struct inode *inode = container_of(head, struct inode, i_rcu);
889 	INIT_LIST_HEAD(&inode->i_dentry);
890 	kmem_cache_free(ext4_inode_cachep, EXT4_I(inode));
891 }
892 
893 static void ext4_destroy_inode(struct inode *inode)
894 {
895 	ext4_ioend_wait(inode);
896 	if (!list_empty(&(EXT4_I(inode)->i_orphan))) {
897 		ext4_msg(inode->i_sb, KERN_ERR,
898 			 "Inode %lu (%p): orphan list check failed!",
899 			 inode->i_ino, EXT4_I(inode));
900 		print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 16, 4,
901 				EXT4_I(inode), sizeof(struct ext4_inode_info),
902 				true);
903 		dump_stack();
904 	}
905 	call_rcu(&inode->i_rcu, ext4_i_callback);
906 }
907 
908 static void init_once(void *foo)
909 {
910 	struct ext4_inode_info *ei = (struct ext4_inode_info *) foo;
911 
912 	INIT_LIST_HEAD(&ei->i_orphan);
913 #ifdef CONFIG_EXT4_FS_XATTR
914 	init_rwsem(&ei->xattr_sem);
915 #endif
916 	init_rwsem(&ei->i_data_sem);
917 	inode_init_once(&ei->vfs_inode);
918 }
919 
920 static int init_inodecache(void)
921 {
922 	ext4_inode_cachep = kmem_cache_create("ext4_inode_cache",
923 					     sizeof(struct ext4_inode_info),
924 					     0, (SLAB_RECLAIM_ACCOUNT|
925 						SLAB_MEM_SPREAD),
926 					     init_once);
927 	if (ext4_inode_cachep == NULL)
928 		return -ENOMEM;
929 	return 0;
930 }
931 
932 static void destroy_inodecache(void)
933 {
934 	kmem_cache_destroy(ext4_inode_cachep);
935 }
936 
937 void ext4_clear_inode(struct inode *inode)
938 {
939 	invalidate_inode_buffers(inode);
940 	end_writeback(inode);
941 	dquot_drop(inode);
942 	ext4_discard_preallocations(inode);
943 	if (EXT4_I(inode)->jinode) {
944 		jbd2_journal_release_jbd_inode(EXT4_JOURNAL(inode),
945 					       EXT4_I(inode)->jinode);
946 		jbd2_free_inode(EXT4_I(inode)->jinode);
947 		EXT4_I(inode)->jinode = NULL;
948 	}
949 }
950 
951 static inline void ext4_show_quota_options(struct seq_file *seq,
952 					   struct super_block *sb)
953 {
954 #if defined(CONFIG_QUOTA)
955 	struct ext4_sb_info *sbi = EXT4_SB(sb);
956 
957 	if (sbi->s_jquota_fmt) {
958 		char *fmtname = "";
959 
960 		switch (sbi->s_jquota_fmt) {
961 		case QFMT_VFS_OLD:
962 			fmtname = "vfsold";
963 			break;
964 		case QFMT_VFS_V0:
965 			fmtname = "vfsv0";
966 			break;
967 		case QFMT_VFS_V1:
968 			fmtname = "vfsv1";
969 			break;
970 		}
971 		seq_printf(seq, ",jqfmt=%s", fmtname);
972 	}
973 
974 	if (sbi->s_qf_names[USRQUOTA])
975 		seq_printf(seq, ",usrjquota=%s", sbi->s_qf_names[USRQUOTA]);
976 
977 	if (sbi->s_qf_names[GRPQUOTA])
978 		seq_printf(seq, ",grpjquota=%s", sbi->s_qf_names[GRPQUOTA]);
979 
980 	if (test_opt(sb, USRQUOTA))
981 		seq_puts(seq, ",usrquota");
982 
983 	if (test_opt(sb, GRPQUOTA))
984 		seq_puts(seq, ",grpquota");
985 #endif
986 }
987 
988 /*
989  * Show an option if
990  *  - it's set to a non-default value OR
991  *  - if the per-sb default is different from the global default
992  */
993 static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs)
994 {
995 	int def_errors;
996 	unsigned long def_mount_opts;
997 	struct super_block *sb = vfs->mnt_sb;
998 	struct ext4_sb_info *sbi = EXT4_SB(sb);
999 	struct ext4_super_block *es = sbi->s_es;
1000 
1001 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
1002 	def_errors     = le16_to_cpu(es->s_errors);
1003 
1004 	if (sbi->s_sb_block != 1)
1005 		seq_printf(seq, ",sb=%llu", sbi->s_sb_block);
1006 	if (test_opt(sb, MINIX_DF))
1007 		seq_puts(seq, ",minixdf");
1008 	if (test_opt(sb, GRPID) && !(def_mount_opts & EXT4_DEFM_BSDGROUPS))
1009 		seq_puts(seq, ",grpid");
1010 	if (!test_opt(sb, GRPID) && (def_mount_opts & EXT4_DEFM_BSDGROUPS))
1011 		seq_puts(seq, ",nogrpid");
1012 	if (sbi->s_resuid != EXT4_DEF_RESUID ||
1013 	    le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID) {
1014 		seq_printf(seq, ",resuid=%u", sbi->s_resuid);
1015 	}
1016 	if (sbi->s_resgid != EXT4_DEF_RESGID ||
1017 	    le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID) {
1018 		seq_printf(seq, ",resgid=%u", sbi->s_resgid);
1019 	}
1020 	if (test_opt(sb, ERRORS_RO)) {
1021 		if (def_errors == EXT4_ERRORS_PANIC ||
1022 		    def_errors == EXT4_ERRORS_CONTINUE) {
1023 			seq_puts(seq, ",errors=remount-ro");
1024 		}
1025 	}
1026 	if (test_opt(sb, ERRORS_CONT) && def_errors != EXT4_ERRORS_CONTINUE)
1027 		seq_puts(seq, ",errors=continue");
1028 	if (test_opt(sb, ERRORS_PANIC) && def_errors != EXT4_ERRORS_PANIC)
1029 		seq_puts(seq, ",errors=panic");
1030 	if (test_opt(sb, NO_UID32) && !(def_mount_opts & EXT4_DEFM_UID16))
1031 		seq_puts(seq, ",nouid32");
1032 	if (test_opt(sb, DEBUG) && !(def_mount_opts & EXT4_DEFM_DEBUG))
1033 		seq_puts(seq, ",debug");
1034 	if (test_opt(sb, OLDALLOC))
1035 		seq_puts(seq, ",oldalloc");
1036 #ifdef CONFIG_EXT4_FS_XATTR
1037 	if (test_opt(sb, XATTR_USER))
1038 		seq_puts(seq, ",user_xattr");
1039 	if (!test_opt(sb, XATTR_USER))
1040 		seq_puts(seq, ",nouser_xattr");
1041 #endif
1042 #ifdef CONFIG_EXT4_FS_POSIX_ACL
1043 	if (test_opt(sb, POSIX_ACL) && !(def_mount_opts & EXT4_DEFM_ACL))
1044 		seq_puts(seq, ",acl");
1045 	if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT4_DEFM_ACL))
1046 		seq_puts(seq, ",noacl");
1047 #endif
1048 	if (sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ) {
1049 		seq_printf(seq, ",commit=%u",
1050 			   (unsigned) (sbi->s_commit_interval / HZ));
1051 	}
1052 	if (sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME) {
1053 		seq_printf(seq, ",min_batch_time=%u",
1054 			   (unsigned) sbi->s_min_batch_time);
1055 	}
1056 	if (sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME) {
1057 		seq_printf(seq, ",max_batch_time=%u",
1058 			   (unsigned) sbi->s_min_batch_time);
1059 	}
1060 
1061 	/*
1062 	 * We're changing the default of barrier mount option, so
1063 	 * let's always display its mount state so it's clear what its
1064 	 * status is.
1065 	 */
1066 	seq_puts(seq, ",barrier=");
1067 	seq_puts(seq, test_opt(sb, BARRIER) ? "1" : "0");
1068 	if (test_opt(sb, JOURNAL_ASYNC_COMMIT))
1069 		seq_puts(seq, ",journal_async_commit");
1070 	else if (test_opt(sb, JOURNAL_CHECKSUM))
1071 		seq_puts(seq, ",journal_checksum");
1072 	if (test_opt(sb, I_VERSION))
1073 		seq_puts(seq, ",i_version");
1074 	if (!test_opt(sb, DELALLOC) &&
1075 	    !(def_mount_opts & EXT4_DEFM_NODELALLOC))
1076 		seq_puts(seq, ",nodelalloc");
1077 
1078 	if (!test_opt(sb, MBLK_IO_SUBMIT))
1079 		seq_puts(seq, ",nomblk_io_submit");
1080 	if (sbi->s_stripe)
1081 		seq_printf(seq, ",stripe=%lu", sbi->s_stripe);
1082 	/*
1083 	 * journal mode get enabled in different ways
1084 	 * So just print the value even if we didn't specify it
1085 	 */
1086 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
1087 		seq_puts(seq, ",data=journal");
1088 	else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
1089 		seq_puts(seq, ",data=ordered");
1090 	else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
1091 		seq_puts(seq, ",data=writeback");
1092 
1093 	if (sbi->s_inode_readahead_blks != EXT4_DEF_INODE_READAHEAD_BLKS)
1094 		seq_printf(seq, ",inode_readahead_blks=%u",
1095 			   sbi->s_inode_readahead_blks);
1096 
1097 	if (test_opt(sb, DATA_ERR_ABORT))
1098 		seq_puts(seq, ",data_err=abort");
1099 
1100 	if (test_opt(sb, NO_AUTO_DA_ALLOC))
1101 		seq_puts(seq, ",noauto_da_alloc");
1102 
1103 	if (test_opt(sb, DISCARD) && !(def_mount_opts & EXT4_DEFM_DISCARD))
1104 		seq_puts(seq, ",discard");
1105 
1106 	if (test_opt(sb, NOLOAD))
1107 		seq_puts(seq, ",norecovery");
1108 
1109 	if (test_opt(sb, DIOREAD_NOLOCK))
1110 		seq_puts(seq, ",dioread_nolock");
1111 
1112 	if (test_opt(sb, BLOCK_VALIDITY) &&
1113 	    !(def_mount_opts & EXT4_DEFM_BLOCK_VALIDITY))
1114 		seq_puts(seq, ",block_validity");
1115 
1116 	if (!test_opt(sb, INIT_INODE_TABLE))
1117 		seq_puts(seq, ",noinit_inode_table");
1118 	else if (sbi->s_li_wait_mult != EXT4_DEF_LI_WAIT_MULT)
1119 		seq_printf(seq, ",init_inode_table=%u",
1120 			   (unsigned) sbi->s_li_wait_mult);
1121 
1122 	ext4_show_quota_options(seq, sb);
1123 
1124 	return 0;
1125 }
1126 
1127 static struct inode *ext4_nfs_get_inode(struct super_block *sb,
1128 					u64 ino, u32 generation)
1129 {
1130 	struct inode *inode;
1131 
1132 	if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
1133 		return ERR_PTR(-ESTALE);
1134 	if (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
1135 		return ERR_PTR(-ESTALE);
1136 
1137 	/* iget isn't really right if the inode is currently unallocated!!
1138 	 *
1139 	 * ext4_read_inode will return a bad_inode if the inode had been
1140 	 * deleted, so we should be safe.
1141 	 *
1142 	 * Currently we don't know the generation for parent directory, so
1143 	 * a generation of 0 means "accept any"
1144 	 */
1145 	inode = ext4_iget(sb, ino);
1146 	if (IS_ERR(inode))
1147 		return ERR_CAST(inode);
1148 	if (generation && inode->i_generation != generation) {
1149 		iput(inode);
1150 		return ERR_PTR(-ESTALE);
1151 	}
1152 
1153 	return inode;
1154 }
1155 
1156 static struct dentry *ext4_fh_to_dentry(struct super_block *sb, struct fid *fid,
1157 					int fh_len, int fh_type)
1158 {
1159 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
1160 				    ext4_nfs_get_inode);
1161 }
1162 
1163 static struct dentry *ext4_fh_to_parent(struct super_block *sb, struct fid *fid,
1164 					int fh_len, int fh_type)
1165 {
1166 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
1167 				    ext4_nfs_get_inode);
1168 }
1169 
1170 /*
1171  * Try to release metadata pages (indirect blocks, directories) which are
1172  * mapped via the block device.  Since these pages could have journal heads
1173  * which would prevent try_to_free_buffers() from freeing them, we must use
1174  * jbd2 layer's try_to_free_buffers() function to release them.
1175  */
1176 static int bdev_try_to_free_page(struct super_block *sb, struct page *page,
1177 				 gfp_t wait)
1178 {
1179 	journal_t *journal = EXT4_SB(sb)->s_journal;
1180 
1181 	WARN_ON(PageChecked(page));
1182 	if (!page_has_buffers(page))
1183 		return 0;
1184 	if (journal)
1185 		return jbd2_journal_try_to_free_buffers(journal, page,
1186 							wait & ~__GFP_WAIT);
1187 	return try_to_free_buffers(page);
1188 }
1189 
1190 #ifdef CONFIG_QUOTA
1191 #define QTYPE2NAME(t) ((t) == USRQUOTA ? "user" : "group")
1192 #define QTYPE2MOPT(on, t) ((t) == USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
1193 
1194 static int ext4_write_dquot(struct dquot *dquot);
1195 static int ext4_acquire_dquot(struct dquot *dquot);
1196 static int ext4_release_dquot(struct dquot *dquot);
1197 static int ext4_mark_dquot_dirty(struct dquot *dquot);
1198 static int ext4_write_info(struct super_block *sb, int type);
1199 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
1200 			 struct path *path);
1201 static int ext4_quota_off(struct super_block *sb, int type);
1202 static int ext4_quota_on_mount(struct super_block *sb, int type);
1203 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
1204 			       size_t len, loff_t off);
1205 static ssize_t ext4_quota_write(struct super_block *sb, int type,
1206 				const char *data, size_t len, loff_t off);
1207 
1208 static const struct dquot_operations ext4_quota_operations = {
1209 	.get_reserved_space = ext4_get_reserved_space,
1210 	.write_dquot	= ext4_write_dquot,
1211 	.acquire_dquot	= ext4_acquire_dquot,
1212 	.release_dquot	= ext4_release_dquot,
1213 	.mark_dirty	= ext4_mark_dquot_dirty,
1214 	.write_info	= ext4_write_info,
1215 	.alloc_dquot	= dquot_alloc,
1216 	.destroy_dquot	= dquot_destroy,
1217 };
1218 
1219 static const struct quotactl_ops ext4_qctl_operations = {
1220 	.quota_on	= ext4_quota_on,
1221 	.quota_off	= ext4_quota_off,
1222 	.quota_sync	= dquot_quota_sync,
1223 	.get_info	= dquot_get_dqinfo,
1224 	.set_info	= dquot_set_dqinfo,
1225 	.get_dqblk	= dquot_get_dqblk,
1226 	.set_dqblk	= dquot_set_dqblk
1227 };
1228 #endif
1229 
1230 static const struct super_operations ext4_sops = {
1231 	.alloc_inode	= ext4_alloc_inode,
1232 	.destroy_inode	= ext4_destroy_inode,
1233 	.write_inode	= ext4_write_inode,
1234 	.dirty_inode	= ext4_dirty_inode,
1235 	.drop_inode	= ext4_drop_inode,
1236 	.evict_inode	= ext4_evict_inode,
1237 	.put_super	= ext4_put_super,
1238 	.sync_fs	= ext4_sync_fs,
1239 	.freeze_fs	= ext4_freeze,
1240 	.unfreeze_fs	= ext4_unfreeze,
1241 	.statfs		= ext4_statfs,
1242 	.remount_fs	= ext4_remount,
1243 	.show_options	= ext4_show_options,
1244 #ifdef CONFIG_QUOTA
1245 	.quota_read	= ext4_quota_read,
1246 	.quota_write	= ext4_quota_write,
1247 #endif
1248 	.bdev_try_to_free_page = bdev_try_to_free_page,
1249 };
1250 
1251 static const struct super_operations ext4_nojournal_sops = {
1252 	.alloc_inode	= ext4_alloc_inode,
1253 	.destroy_inode	= ext4_destroy_inode,
1254 	.write_inode	= ext4_write_inode,
1255 	.dirty_inode	= ext4_dirty_inode,
1256 	.drop_inode	= ext4_drop_inode,
1257 	.evict_inode	= ext4_evict_inode,
1258 	.write_super	= ext4_write_super,
1259 	.put_super	= ext4_put_super,
1260 	.statfs		= ext4_statfs,
1261 	.remount_fs	= ext4_remount,
1262 	.show_options	= ext4_show_options,
1263 #ifdef CONFIG_QUOTA
1264 	.quota_read	= ext4_quota_read,
1265 	.quota_write	= ext4_quota_write,
1266 #endif
1267 	.bdev_try_to_free_page = bdev_try_to_free_page,
1268 };
1269 
1270 static const struct export_operations ext4_export_ops = {
1271 	.fh_to_dentry = ext4_fh_to_dentry,
1272 	.fh_to_parent = ext4_fh_to_parent,
1273 	.get_parent = ext4_get_parent,
1274 };
1275 
1276 enum {
1277 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
1278 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
1279 	Opt_nouid32, Opt_debug, Opt_oldalloc, Opt_orlov,
1280 	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
1281 	Opt_auto_da_alloc, Opt_noauto_da_alloc, Opt_noload, Opt_nobh, Opt_bh,
1282 	Opt_commit, Opt_min_batch_time, Opt_max_batch_time,
1283 	Opt_journal_update, Opt_journal_dev,
1284 	Opt_journal_checksum, Opt_journal_async_commit,
1285 	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
1286 	Opt_data_err_abort, Opt_data_err_ignore,
1287 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
1288 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
1289 	Opt_noquota, Opt_ignore, Opt_barrier, Opt_nobarrier, Opt_err,
1290 	Opt_resize, Opt_usrquota, Opt_grpquota, Opt_i_version,
1291 	Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_mblk_io_submit,
1292 	Opt_nomblk_io_submit, Opt_block_validity, Opt_noblock_validity,
1293 	Opt_inode_readahead_blks, Opt_journal_ioprio,
1294 	Opt_dioread_nolock, Opt_dioread_lock,
1295 	Opt_discard, Opt_nodiscard,
1296 	Opt_init_inode_table, Opt_noinit_inode_table,
1297 };
1298 
1299 static const match_table_t tokens = {
1300 	{Opt_bsd_df, "bsddf"},
1301 	{Opt_minix_df, "minixdf"},
1302 	{Opt_grpid, "grpid"},
1303 	{Opt_grpid, "bsdgroups"},
1304 	{Opt_nogrpid, "nogrpid"},
1305 	{Opt_nogrpid, "sysvgroups"},
1306 	{Opt_resgid, "resgid=%u"},
1307 	{Opt_resuid, "resuid=%u"},
1308 	{Opt_sb, "sb=%u"},
1309 	{Opt_err_cont, "errors=continue"},
1310 	{Opt_err_panic, "errors=panic"},
1311 	{Opt_err_ro, "errors=remount-ro"},
1312 	{Opt_nouid32, "nouid32"},
1313 	{Opt_debug, "debug"},
1314 	{Opt_oldalloc, "oldalloc"},
1315 	{Opt_orlov, "orlov"},
1316 	{Opt_user_xattr, "user_xattr"},
1317 	{Opt_nouser_xattr, "nouser_xattr"},
1318 	{Opt_acl, "acl"},
1319 	{Opt_noacl, "noacl"},
1320 	{Opt_noload, "noload"},
1321 	{Opt_noload, "norecovery"},
1322 	{Opt_nobh, "nobh"},
1323 	{Opt_bh, "bh"},
1324 	{Opt_commit, "commit=%u"},
1325 	{Opt_min_batch_time, "min_batch_time=%u"},
1326 	{Opt_max_batch_time, "max_batch_time=%u"},
1327 	{Opt_journal_update, "journal=update"},
1328 	{Opt_journal_dev, "journal_dev=%u"},
1329 	{Opt_journal_checksum, "journal_checksum"},
1330 	{Opt_journal_async_commit, "journal_async_commit"},
1331 	{Opt_abort, "abort"},
1332 	{Opt_data_journal, "data=journal"},
1333 	{Opt_data_ordered, "data=ordered"},
1334 	{Opt_data_writeback, "data=writeback"},
1335 	{Opt_data_err_abort, "data_err=abort"},
1336 	{Opt_data_err_ignore, "data_err=ignore"},
1337 	{Opt_offusrjquota, "usrjquota="},
1338 	{Opt_usrjquota, "usrjquota=%s"},
1339 	{Opt_offgrpjquota, "grpjquota="},
1340 	{Opt_grpjquota, "grpjquota=%s"},
1341 	{Opt_jqfmt_vfsold, "jqfmt=vfsold"},
1342 	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
1343 	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
1344 	{Opt_grpquota, "grpquota"},
1345 	{Opt_noquota, "noquota"},
1346 	{Opt_quota, "quota"},
1347 	{Opt_usrquota, "usrquota"},
1348 	{Opt_barrier, "barrier=%u"},
1349 	{Opt_barrier, "barrier"},
1350 	{Opt_nobarrier, "nobarrier"},
1351 	{Opt_i_version, "i_version"},
1352 	{Opt_stripe, "stripe=%u"},
1353 	{Opt_resize, "resize"},
1354 	{Opt_delalloc, "delalloc"},
1355 	{Opt_nodelalloc, "nodelalloc"},
1356 	{Opt_mblk_io_submit, "mblk_io_submit"},
1357 	{Opt_nomblk_io_submit, "nomblk_io_submit"},
1358 	{Opt_block_validity, "block_validity"},
1359 	{Opt_noblock_validity, "noblock_validity"},
1360 	{Opt_inode_readahead_blks, "inode_readahead_blks=%u"},
1361 	{Opt_journal_ioprio, "journal_ioprio=%u"},
1362 	{Opt_auto_da_alloc, "auto_da_alloc=%u"},
1363 	{Opt_auto_da_alloc, "auto_da_alloc"},
1364 	{Opt_noauto_da_alloc, "noauto_da_alloc"},
1365 	{Opt_dioread_nolock, "dioread_nolock"},
1366 	{Opt_dioread_lock, "dioread_lock"},
1367 	{Opt_discard, "discard"},
1368 	{Opt_nodiscard, "nodiscard"},
1369 	{Opt_init_inode_table, "init_itable=%u"},
1370 	{Opt_init_inode_table, "init_itable"},
1371 	{Opt_noinit_inode_table, "noinit_itable"},
1372 	{Opt_err, NULL},
1373 };
1374 
1375 static ext4_fsblk_t get_sb_block(void **data)
1376 {
1377 	ext4_fsblk_t	sb_block;
1378 	char		*options = (char *) *data;
1379 
1380 	if (!options || strncmp(options, "sb=", 3) != 0)
1381 		return 1;	/* Default location */
1382 
1383 	options += 3;
1384 	/* TODO: use simple_strtoll with >32bit ext4 */
1385 	sb_block = simple_strtoul(options, &options, 0);
1386 	if (*options && *options != ',') {
1387 		printk(KERN_ERR "EXT4-fs: Invalid sb specification: %s\n",
1388 		       (char *) *data);
1389 		return 1;
1390 	}
1391 	if (*options == ',')
1392 		options++;
1393 	*data = (void *) options;
1394 
1395 	return sb_block;
1396 }
1397 
1398 #define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))
1399 static char deprecated_msg[] = "Mount option \"%s\" will be removed by %s\n"
1400 	"Contact linux-ext4@vger.kernel.org if you think we should keep it.\n";
1401 
1402 #ifdef CONFIG_QUOTA
1403 static int set_qf_name(struct super_block *sb, int qtype, substring_t *args)
1404 {
1405 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1406 	char *qname;
1407 
1408 	if (sb_any_quota_loaded(sb) &&
1409 		!sbi->s_qf_names[qtype]) {
1410 		ext4_msg(sb, KERN_ERR,
1411 			"Cannot change journaled "
1412 			"quota options when quota turned on");
1413 		return 0;
1414 	}
1415 	qname = match_strdup(args);
1416 	if (!qname) {
1417 		ext4_msg(sb, KERN_ERR,
1418 			"Not enough memory for storing quotafile name");
1419 		return 0;
1420 	}
1421 	if (sbi->s_qf_names[qtype] &&
1422 		strcmp(sbi->s_qf_names[qtype], qname)) {
1423 		ext4_msg(sb, KERN_ERR,
1424 			"%s quota file already specified", QTYPE2NAME(qtype));
1425 		kfree(qname);
1426 		return 0;
1427 	}
1428 	sbi->s_qf_names[qtype] = qname;
1429 	if (strchr(sbi->s_qf_names[qtype], '/')) {
1430 		ext4_msg(sb, KERN_ERR,
1431 			"quotafile must be on filesystem root");
1432 		kfree(sbi->s_qf_names[qtype]);
1433 		sbi->s_qf_names[qtype] = NULL;
1434 		return 0;
1435 	}
1436 	set_opt(sb, QUOTA);
1437 	return 1;
1438 }
1439 
1440 static int clear_qf_name(struct super_block *sb, int qtype)
1441 {
1442 
1443 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1444 
1445 	if (sb_any_quota_loaded(sb) &&
1446 		sbi->s_qf_names[qtype]) {
1447 		ext4_msg(sb, KERN_ERR, "Cannot change journaled quota options"
1448 			" when quota turned on");
1449 		return 0;
1450 	}
1451 	/*
1452 	 * The space will be released later when all options are confirmed
1453 	 * to be correct
1454 	 */
1455 	sbi->s_qf_names[qtype] = NULL;
1456 	return 1;
1457 }
1458 #endif
1459 
1460 static int parse_options(char *options, struct super_block *sb,
1461 			 unsigned long *journal_devnum,
1462 			 unsigned int *journal_ioprio,
1463 			 ext4_fsblk_t *n_blocks_count, int is_remount)
1464 {
1465 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1466 	char *p;
1467 	substring_t args[MAX_OPT_ARGS];
1468 	int data_opt = 0;
1469 	int option;
1470 #ifdef CONFIG_QUOTA
1471 	int qfmt;
1472 #endif
1473 
1474 	if (!options)
1475 		return 1;
1476 
1477 	while ((p = strsep(&options, ",")) != NULL) {
1478 		int token;
1479 		if (!*p)
1480 			continue;
1481 
1482 		/*
1483 		 * Initialize args struct so we know whether arg was
1484 		 * found; some options take optional arguments.
1485 		 */
1486 		args[0].to = args[0].from = NULL;
1487 		token = match_token(p, tokens, args);
1488 		switch (token) {
1489 		case Opt_bsd_df:
1490 			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
1491 			clear_opt(sb, MINIX_DF);
1492 			break;
1493 		case Opt_minix_df:
1494 			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
1495 			set_opt(sb, MINIX_DF);
1496 
1497 			break;
1498 		case Opt_grpid:
1499 			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
1500 			set_opt(sb, GRPID);
1501 
1502 			break;
1503 		case Opt_nogrpid:
1504 			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
1505 			clear_opt(sb, GRPID);
1506 
1507 			break;
1508 		case Opt_resuid:
1509 			if (match_int(&args[0], &option))
1510 				return 0;
1511 			sbi->s_resuid = option;
1512 			break;
1513 		case Opt_resgid:
1514 			if (match_int(&args[0], &option))
1515 				return 0;
1516 			sbi->s_resgid = option;
1517 			break;
1518 		case Opt_sb:
1519 			/* handled by get_sb_block() instead of here */
1520 			/* *sb_block = match_int(&args[0]); */
1521 			break;
1522 		case Opt_err_panic:
1523 			clear_opt(sb, ERRORS_CONT);
1524 			clear_opt(sb, ERRORS_RO);
1525 			set_opt(sb, ERRORS_PANIC);
1526 			break;
1527 		case Opt_err_ro:
1528 			clear_opt(sb, ERRORS_CONT);
1529 			clear_opt(sb, ERRORS_PANIC);
1530 			set_opt(sb, ERRORS_RO);
1531 			break;
1532 		case Opt_err_cont:
1533 			clear_opt(sb, ERRORS_RO);
1534 			clear_opt(sb, ERRORS_PANIC);
1535 			set_opt(sb, ERRORS_CONT);
1536 			break;
1537 		case Opt_nouid32:
1538 			set_opt(sb, NO_UID32);
1539 			break;
1540 		case Opt_debug:
1541 			set_opt(sb, DEBUG);
1542 			break;
1543 		case Opt_oldalloc:
1544 			set_opt(sb, OLDALLOC);
1545 			break;
1546 		case Opt_orlov:
1547 			clear_opt(sb, OLDALLOC);
1548 			break;
1549 #ifdef CONFIG_EXT4_FS_XATTR
1550 		case Opt_user_xattr:
1551 			set_opt(sb, XATTR_USER);
1552 			break;
1553 		case Opt_nouser_xattr:
1554 			clear_opt(sb, XATTR_USER);
1555 			break;
1556 #else
1557 		case Opt_user_xattr:
1558 		case Opt_nouser_xattr:
1559 			ext4_msg(sb, KERN_ERR, "(no)user_xattr options not supported");
1560 			break;
1561 #endif
1562 #ifdef CONFIG_EXT4_FS_POSIX_ACL
1563 		case Opt_acl:
1564 			set_opt(sb, POSIX_ACL);
1565 			break;
1566 		case Opt_noacl:
1567 			clear_opt(sb, POSIX_ACL);
1568 			break;
1569 #else
1570 		case Opt_acl:
1571 		case Opt_noacl:
1572 			ext4_msg(sb, KERN_ERR, "(no)acl options not supported");
1573 			break;
1574 #endif
1575 		case Opt_journal_update:
1576 			/* @@@ FIXME */
1577 			/* Eventually we will want to be able to create
1578 			   a journal file here.  For now, only allow the
1579 			   user to specify an existing inode to be the
1580 			   journal file. */
1581 			if (is_remount) {
1582 				ext4_msg(sb, KERN_ERR,
1583 					 "Cannot specify journal on remount");
1584 				return 0;
1585 			}
1586 			set_opt(sb, UPDATE_JOURNAL);
1587 			break;
1588 		case Opt_journal_dev:
1589 			if (is_remount) {
1590 				ext4_msg(sb, KERN_ERR,
1591 					"Cannot specify journal on remount");
1592 				return 0;
1593 			}
1594 			if (match_int(&args[0], &option))
1595 				return 0;
1596 			*journal_devnum = option;
1597 			break;
1598 		case Opt_journal_checksum:
1599 			set_opt(sb, JOURNAL_CHECKSUM);
1600 			break;
1601 		case Opt_journal_async_commit:
1602 			set_opt(sb, JOURNAL_ASYNC_COMMIT);
1603 			set_opt(sb, JOURNAL_CHECKSUM);
1604 			break;
1605 		case Opt_noload:
1606 			set_opt(sb, NOLOAD);
1607 			break;
1608 		case Opt_commit:
1609 			if (match_int(&args[0], &option))
1610 				return 0;
1611 			if (option < 0)
1612 				return 0;
1613 			if (option == 0)
1614 				option = JBD2_DEFAULT_MAX_COMMIT_AGE;
1615 			sbi->s_commit_interval = HZ * option;
1616 			break;
1617 		case Opt_max_batch_time:
1618 			if (match_int(&args[0], &option))
1619 				return 0;
1620 			if (option < 0)
1621 				return 0;
1622 			if (option == 0)
1623 				option = EXT4_DEF_MAX_BATCH_TIME;
1624 			sbi->s_max_batch_time = option;
1625 			break;
1626 		case Opt_min_batch_time:
1627 			if (match_int(&args[0], &option))
1628 				return 0;
1629 			if (option < 0)
1630 				return 0;
1631 			sbi->s_min_batch_time = option;
1632 			break;
1633 		case Opt_data_journal:
1634 			data_opt = EXT4_MOUNT_JOURNAL_DATA;
1635 			goto datacheck;
1636 		case Opt_data_ordered:
1637 			data_opt = EXT4_MOUNT_ORDERED_DATA;
1638 			goto datacheck;
1639 		case Opt_data_writeback:
1640 			data_opt = EXT4_MOUNT_WRITEBACK_DATA;
1641 		datacheck:
1642 			if (is_remount) {
1643 				if (test_opt(sb, DATA_FLAGS) != data_opt) {
1644 					ext4_msg(sb, KERN_ERR,
1645 						"Cannot change data mode on remount");
1646 					return 0;
1647 				}
1648 			} else {
1649 				clear_opt(sb, DATA_FLAGS);
1650 				sbi->s_mount_opt |= data_opt;
1651 			}
1652 			break;
1653 		case Opt_data_err_abort:
1654 			set_opt(sb, DATA_ERR_ABORT);
1655 			break;
1656 		case Opt_data_err_ignore:
1657 			clear_opt(sb, DATA_ERR_ABORT);
1658 			break;
1659 #ifdef CONFIG_QUOTA
1660 		case Opt_usrjquota:
1661 			if (!set_qf_name(sb, USRQUOTA, &args[0]))
1662 				return 0;
1663 			break;
1664 		case Opt_grpjquota:
1665 			if (!set_qf_name(sb, GRPQUOTA, &args[0]))
1666 				return 0;
1667 			break;
1668 		case Opt_offusrjquota:
1669 			if (!clear_qf_name(sb, USRQUOTA))
1670 				return 0;
1671 			break;
1672 		case Opt_offgrpjquota:
1673 			if (!clear_qf_name(sb, GRPQUOTA))
1674 				return 0;
1675 			break;
1676 
1677 		case Opt_jqfmt_vfsold:
1678 			qfmt = QFMT_VFS_OLD;
1679 			goto set_qf_format;
1680 		case Opt_jqfmt_vfsv0:
1681 			qfmt = QFMT_VFS_V0;
1682 			goto set_qf_format;
1683 		case Opt_jqfmt_vfsv1:
1684 			qfmt = QFMT_VFS_V1;
1685 set_qf_format:
1686 			if (sb_any_quota_loaded(sb) &&
1687 			    sbi->s_jquota_fmt != qfmt) {
1688 				ext4_msg(sb, KERN_ERR, "Cannot change "
1689 					"journaled quota options when "
1690 					"quota turned on");
1691 				return 0;
1692 			}
1693 			sbi->s_jquota_fmt = qfmt;
1694 			break;
1695 		case Opt_quota:
1696 		case Opt_usrquota:
1697 			set_opt(sb, QUOTA);
1698 			set_opt(sb, USRQUOTA);
1699 			break;
1700 		case Opt_grpquota:
1701 			set_opt(sb, QUOTA);
1702 			set_opt(sb, GRPQUOTA);
1703 			break;
1704 		case Opt_noquota:
1705 			if (sb_any_quota_loaded(sb)) {
1706 				ext4_msg(sb, KERN_ERR, "Cannot change quota "
1707 					"options when quota turned on");
1708 				return 0;
1709 			}
1710 			clear_opt(sb, QUOTA);
1711 			clear_opt(sb, USRQUOTA);
1712 			clear_opt(sb, GRPQUOTA);
1713 			break;
1714 #else
1715 		case Opt_quota:
1716 		case Opt_usrquota:
1717 		case Opt_grpquota:
1718 			ext4_msg(sb, KERN_ERR,
1719 				"quota options not supported");
1720 			break;
1721 		case Opt_usrjquota:
1722 		case Opt_grpjquota:
1723 		case Opt_offusrjquota:
1724 		case Opt_offgrpjquota:
1725 		case Opt_jqfmt_vfsold:
1726 		case Opt_jqfmt_vfsv0:
1727 		case Opt_jqfmt_vfsv1:
1728 			ext4_msg(sb, KERN_ERR,
1729 				"journaled quota options not supported");
1730 			break;
1731 		case Opt_noquota:
1732 			break;
1733 #endif
1734 		case Opt_abort:
1735 			sbi->s_mount_flags |= EXT4_MF_FS_ABORTED;
1736 			break;
1737 		case Opt_nobarrier:
1738 			clear_opt(sb, BARRIER);
1739 			break;
1740 		case Opt_barrier:
1741 			if (args[0].from) {
1742 				if (match_int(&args[0], &option))
1743 					return 0;
1744 			} else
1745 				option = 1;	/* No argument, default to 1 */
1746 			if (option)
1747 				set_opt(sb, BARRIER);
1748 			else
1749 				clear_opt(sb, BARRIER);
1750 			break;
1751 		case Opt_ignore:
1752 			break;
1753 		case Opt_resize:
1754 			if (!is_remount) {
1755 				ext4_msg(sb, KERN_ERR,
1756 					"resize option only available "
1757 					"for remount");
1758 				return 0;
1759 			}
1760 			if (match_int(&args[0], &option) != 0)
1761 				return 0;
1762 			*n_blocks_count = option;
1763 			break;
1764 		case Opt_nobh:
1765 			ext4_msg(sb, KERN_WARNING,
1766 				 "Ignoring deprecated nobh option");
1767 			break;
1768 		case Opt_bh:
1769 			ext4_msg(sb, KERN_WARNING,
1770 				 "Ignoring deprecated bh option");
1771 			break;
1772 		case Opt_i_version:
1773 			set_opt(sb, I_VERSION);
1774 			sb->s_flags |= MS_I_VERSION;
1775 			break;
1776 		case Opt_nodelalloc:
1777 			clear_opt(sb, DELALLOC);
1778 			break;
1779 		case Opt_mblk_io_submit:
1780 			set_opt(sb, MBLK_IO_SUBMIT);
1781 			break;
1782 		case Opt_nomblk_io_submit:
1783 			clear_opt(sb, MBLK_IO_SUBMIT);
1784 			break;
1785 		case Opt_stripe:
1786 			if (match_int(&args[0], &option))
1787 				return 0;
1788 			if (option < 0)
1789 				return 0;
1790 			sbi->s_stripe = option;
1791 			break;
1792 		case Opt_delalloc:
1793 			set_opt(sb, DELALLOC);
1794 			break;
1795 		case Opt_block_validity:
1796 			set_opt(sb, BLOCK_VALIDITY);
1797 			break;
1798 		case Opt_noblock_validity:
1799 			clear_opt(sb, BLOCK_VALIDITY);
1800 			break;
1801 		case Opt_inode_readahead_blks:
1802 			if (match_int(&args[0], &option))
1803 				return 0;
1804 			if (option < 0 || option > (1 << 30))
1805 				return 0;
1806 			if (option && !is_power_of_2(option)) {
1807 				ext4_msg(sb, KERN_ERR,
1808 					 "EXT4-fs: inode_readahead_blks"
1809 					 " must be a power of 2");
1810 				return 0;
1811 			}
1812 			sbi->s_inode_readahead_blks = option;
1813 			break;
1814 		case Opt_journal_ioprio:
1815 			if (match_int(&args[0], &option))
1816 				return 0;
1817 			if (option < 0 || option > 7)
1818 				break;
1819 			*journal_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE,
1820 							    option);
1821 			break;
1822 		case Opt_noauto_da_alloc:
1823 			set_opt(sb, NO_AUTO_DA_ALLOC);
1824 			break;
1825 		case Opt_auto_da_alloc:
1826 			if (args[0].from) {
1827 				if (match_int(&args[0], &option))
1828 					return 0;
1829 			} else
1830 				option = 1;	/* No argument, default to 1 */
1831 			if (option)
1832 				clear_opt(sb, NO_AUTO_DA_ALLOC);
1833 			else
1834 				set_opt(sb,NO_AUTO_DA_ALLOC);
1835 			break;
1836 		case Opt_discard:
1837 			set_opt(sb, DISCARD);
1838 			break;
1839 		case Opt_nodiscard:
1840 			clear_opt(sb, DISCARD);
1841 			break;
1842 		case Opt_dioread_nolock:
1843 			set_opt(sb, DIOREAD_NOLOCK);
1844 			break;
1845 		case Opt_dioread_lock:
1846 			clear_opt(sb, DIOREAD_NOLOCK);
1847 			break;
1848 		case Opt_init_inode_table:
1849 			set_opt(sb, INIT_INODE_TABLE);
1850 			if (args[0].from) {
1851 				if (match_int(&args[0], &option))
1852 					return 0;
1853 			} else
1854 				option = EXT4_DEF_LI_WAIT_MULT;
1855 			if (option < 0)
1856 				return 0;
1857 			sbi->s_li_wait_mult = option;
1858 			break;
1859 		case Opt_noinit_inode_table:
1860 			clear_opt(sb, INIT_INODE_TABLE);
1861 			break;
1862 		default:
1863 			ext4_msg(sb, KERN_ERR,
1864 			       "Unrecognized mount option \"%s\" "
1865 			       "or missing value", p);
1866 			return 0;
1867 		}
1868 	}
1869 #ifdef CONFIG_QUOTA
1870 	if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
1871 		if (test_opt(sb, USRQUOTA) && sbi->s_qf_names[USRQUOTA])
1872 			clear_opt(sb, USRQUOTA);
1873 
1874 		if (test_opt(sb, GRPQUOTA) && sbi->s_qf_names[GRPQUOTA])
1875 			clear_opt(sb, GRPQUOTA);
1876 
1877 		if (test_opt(sb, GRPQUOTA) || test_opt(sb, USRQUOTA)) {
1878 			ext4_msg(sb, KERN_ERR, "old and new quota "
1879 					"format mixing");
1880 			return 0;
1881 		}
1882 
1883 		if (!sbi->s_jquota_fmt) {
1884 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1885 					"not specified");
1886 			return 0;
1887 		}
1888 	} else {
1889 		if (sbi->s_jquota_fmt) {
1890 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1891 					"specified with no journaling "
1892 					"enabled");
1893 			return 0;
1894 		}
1895 	}
1896 #endif
1897 	return 1;
1898 }
1899 
1900 static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
1901 			    int read_only)
1902 {
1903 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1904 	int res = 0;
1905 
1906 	if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
1907 		ext4_msg(sb, KERN_ERR, "revision level too high, "
1908 			 "forcing read-only mode");
1909 		res = MS_RDONLY;
1910 	}
1911 	if (read_only)
1912 		return res;
1913 	if (!(sbi->s_mount_state & EXT4_VALID_FS))
1914 		ext4_msg(sb, KERN_WARNING, "warning: mounting unchecked fs, "
1915 			 "running e2fsck is recommended");
1916 	else if ((sbi->s_mount_state & EXT4_ERROR_FS))
1917 		ext4_msg(sb, KERN_WARNING,
1918 			 "warning: mounting fs with errors, "
1919 			 "running e2fsck is recommended");
1920 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) > 0 &&
1921 		 le16_to_cpu(es->s_mnt_count) >=
1922 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
1923 		ext4_msg(sb, KERN_WARNING,
1924 			 "warning: maximal mount count reached, "
1925 			 "running e2fsck is recommended");
1926 	else if (le32_to_cpu(es->s_checkinterval) &&
1927 		(le32_to_cpu(es->s_lastcheck) +
1928 			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
1929 		ext4_msg(sb, KERN_WARNING,
1930 			 "warning: checktime reached, "
1931 			 "running e2fsck is recommended");
1932 	if (!sbi->s_journal)
1933 		es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1934 	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
1935 		es->s_max_mnt_count = cpu_to_le16(EXT4_DFL_MAX_MNT_COUNT);
1936 	le16_add_cpu(&es->s_mnt_count, 1);
1937 	es->s_mtime = cpu_to_le32(get_seconds());
1938 	ext4_update_dynamic_rev(sb);
1939 	if (sbi->s_journal)
1940 		EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
1941 
1942 	ext4_commit_super(sb, 1);
1943 	if (test_opt(sb, DEBUG))
1944 		printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, "
1945 				"bpg=%lu, ipg=%lu, mo=%04x, mo2=%04x]\n",
1946 			sb->s_blocksize,
1947 			sbi->s_groups_count,
1948 			EXT4_BLOCKS_PER_GROUP(sb),
1949 			EXT4_INODES_PER_GROUP(sb),
1950 			sbi->s_mount_opt, sbi->s_mount_opt2);
1951 
1952 	cleancache_init_fs(sb);
1953 	return res;
1954 }
1955 
1956 static int ext4_fill_flex_info(struct super_block *sb)
1957 {
1958 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1959 	struct ext4_group_desc *gdp = NULL;
1960 	ext4_group_t flex_group_count;
1961 	ext4_group_t flex_group;
1962 	int groups_per_flex = 0;
1963 	size_t size;
1964 	int i;
1965 
1966 	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
1967 	groups_per_flex = 1 << sbi->s_log_groups_per_flex;
1968 
1969 	if (groups_per_flex < 2) {
1970 		sbi->s_log_groups_per_flex = 0;
1971 		return 1;
1972 	}
1973 
1974 	/* We allocate both existing and potentially added groups */
1975 	flex_group_count = ((sbi->s_groups_count + groups_per_flex - 1) +
1976 			((le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) + 1) <<
1977 			      EXT4_DESC_PER_BLOCK_BITS(sb))) / groups_per_flex;
1978 	size = flex_group_count * sizeof(struct flex_groups);
1979 	sbi->s_flex_groups = kzalloc(size, GFP_KERNEL);
1980 	if (sbi->s_flex_groups == NULL) {
1981 		sbi->s_flex_groups = vzalloc(size);
1982 		if (sbi->s_flex_groups == NULL) {
1983 			ext4_msg(sb, KERN_ERR,
1984 				 "not enough memory for %u flex groups",
1985 				 flex_group_count);
1986 			goto failed;
1987 		}
1988 	}
1989 
1990 	for (i = 0; i < sbi->s_groups_count; i++) {
1991 		gdp = ext4_get_group_desc(sb, i, NULL);
1992 
1993 		flex_group = ext4_flex_group(sbi, i);
1994 		atomic_add(ext4_free_inodes_count(sb, gdp),
1995 			   &sbi->s_flex_groups[flex_group].free_inodes);
1996 		atomic_add(ext4_free_blks_count(sb, gdp),
1997 			   &sbi->s_flex_groups[flex_group].free_blocks);
1998 		atomic_add(ext4_used_dirs_count(sb, gdp),
1999 			   &sbi->s_flex_groups[flex_group].used_dirs);
2000 	}
2001 
2002 	return 1;
2003 failed:
2004 	return 0;
2005 }
2006 
2007 __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
2008 			    struct ext4_group_desc *gdp)
2009 {
2010 	__u16 crc = 0;
2011 
2012 	if (sbi->s_es->s_feature_ro_compat &
2013 	    cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
2014 		int offset = offsetof(struct ext4_group_desc, bg_checksum);
2015 		__le32 le_group = cpu_to_le32(block_group);
2016 
2017 		crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
2018 		crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
2019 		crc = crc16(crc, (__u8 *)gdp, offset);
2020 		offset += sizeof(gdp->bg_checksum); /* skip checksum */
2021 		/* for checksum of struct ext4_group_desc do the rest...*/
2022 		if ((sbi->s_es->s_feature_incompat &
2023 		     cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) &&
2024 		    offset < le16_to_cpu(sbi->s_es->s_desc_size))
2025 			crc = crc16(crc, (__u8 *)gdp + offset,
2026 				    le16_to_cpu(sbi->s_es->s_desc_size) -
2027 					offset);
2028 	}
2029 
2030 	return cpu_to_le16(crc);
2031 }
2032 
2033 int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 block_group,
2034 				struct ext4_group_desc *gdp)
2035 {
2036 	if ((sbi->s_es->s_feature_ro_compat &
2037 	     cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) &&
2038 	    (gdp->bg_checksum != ext4_group_desc_csum(sbi, block_group, gdp)))
2039 		return 0;
2040 
2041 	return 1;
2042 }
2043 
2044 /* Called at mount-time, super-block is locked */
2045 static int ext4_check_descriptors(struct super_block *sb,
2046 				  ext4_group_t *first_not_zeroed)
2047 {
2048 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2049 	ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
2050 	ext4_fsblk_t last_block;
2051 	ext4_fsblk_t block_bitmap;
2052 	ext4_fsblk_t inode_bitmap;
2053 	ext4_fsblk_t inode_table;
2054 	int flexbg_flag = 0;
2055 	ext4_group_t i, grp = sbi->s_groups_count;
2056 
2057 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
2058 		flexbg_flag = 1;
2059 
2060 	ext4_debug("Checking group descriptors");
2061 
2062 	for (i = 0; i < sbi->s_groups_count; i++) {
2063 		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
2064 
2065 		if (i == sbi->s_groups_count - 1 || flexbg_flag)
2066 			last_block = ext4_blocks_count(sbi->s_es) - 1;
2067 		else
2068 			last_block = first_block +
2069 				(EXT4_BLOCKS_PER_GROUP(sb) - 1);
2070 
2071 		if ((grp == sbi->s_groups_count) &&
2072 		   !(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2073 			grp = i;
2074 
2075 		block_bitmap = ext4_block_bitmap(sb, gdp);
2076 		if (block_bitmap < first_block || block_bitmap > last_block) {
2077 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2078 			       "Block bitmap for group %u not in group "
2079 			       "(block %llu)!", i, block_bitmap);
2080 			return 0;
2081 		}
2082 		inode_bitmap = ext4_inode_bitmap(sb, gdp);
2083 		if (inode_bitmap < first_block || inode_bitmap > last_block) {
2084 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2085 			       "Inode bitmap for group %u not in group "
2086 			       "(block %llu)!", i, inode_bitmap);
2087 			return 0;
2088 		}
2089 		inode_table = ext4_inode_table(sb, gdp);
2090 		if (inode_table < first_block ||
2091 		    inode_table + sbi->s_itb_per_group - 1 > last_block) {
2092 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2093 			       "Inode table for group %u not in group "
2094 			       "(block %llu)!", i, inode_table);
2095 			return 0;
2096 		}
2097 		ext4_lock_group(sb, i);
2098 		if (!ext4_group_desc_csum_verify(sbi, i, gdp)) {
2099 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2100 				 "Checksum for group %u failed (%u!=%u)",
2101 				 i, le16_to_cpu(ext4_group_desc_csum(sbi, i,
2102 				     gdp)), le16_to_cpu(gdp->bg_checksum));
2103 			if (!(sb->s_flags & MS_RDONLY)) {
2104 				ext4_unlock_group(sb, i);
2105 				return 0;
2106 			}
2107 		}
2108 		ext4_unlock_group(sb, i);
2109 		if (!flexbg_flag)
2110 			first_block += EXT4_BLOCKS_PER_GROUP(sb);
2111 	}
2112 	if (NULL != first_not_zeroed)
2113 		*first_not_zeroed = grp;
2114 
2115 	ext4_free_blocks_count_set(sbi->s_es, ext4_count_free_blocks(sb));
2116 	sbi->s_es->s_free_inodes_count =cpu_to_le32(ext4_count_free_inodes(sb));
2117 	return 1;
2118 }
2119 
2120 /* ext4_orphan_cleanup() walks a singly-linked list of inodes (starting at
2121  * the superblock) which were deleted from all directories, but held open by
2122  * a process at the time of a crash.  We walk the list and try to delete these
2123  * inodes at recovery time (only with a read-write filesystem).
2124  *
2125  * In order to keep the orphan inode chain consistent during traversal (in
2126  * case of crash during recovery), we link each inode into the superblock
2127  * orphan list_head and handle it the same way as an inode deletion during
2128  * normal operation (which journals the operations for us).
2129  *
2130  * We only do an iget() and an iput() on each inode, which is very safe if we
2131  * accidentally point at an in-use or already deleted inode.  The worst that
2132  * can happen in this case is that we get a "bit already cleared" message from
2133  * ext4_free_inode().  The only reason we would point at a wrong inode is if
2134  * e2fsck was run on this filesystem, and it must have already done the orphan
2135  * inode cleanup for us, so we can safely abort without any further action.
2136  */
2137 static void ext4_orphan_cleanup(struct super_block *sb,
2138 				struct ext4_super_block *es)
2139 {
2140 	unsigned int s_flags = sb->s_flags;
2141 	int nr_orphans = 0, nr_truncates = 0;
2142 #ifdef CONFIG_QUOTA
2143 	int i;
2144 #endif
2145 	if (!es->s_last_orphan) {
2146 		jbd_debug(4, "no orphan inodes to clean up\n");
2147 		return;
2148 	}
2149 
2150 	if (bdev_read_only(sb->s_bdev)) {
2151 		ext4_msg(sb, KERN_ERR, "write access "
2152 			"unavailable, skipping orphan cleanup");
2153 		return;
2154 	}
2155 
2156 	/* Check if feature set would not allow a r/w mount */
2157 	if (!ext4_feature_set_ok(sb, 0)) {
2158 		ext4_msg(sb, KERN_INFO, "Skipping orphan cleanup due to "
2159 			 "unknown ROCOMPAT features");
2160 		return;
2161 	}
2162 
2163 	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
2164 		if (es->s_last_orphan)
2165 			jbd_debug(1, "Errors on filesystem, "
2166 				  "clearing orphan list.\n");
2167 		es->s_last_orphan = 0;
2168 		jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
2169 		return;
2170 	}
2171 
2172 	if (s_flags & MS_RDONLY) {
2173 		ext4_msg(sb, KERN_INFO, "orphan cleanup on readonly fs");
2174 		sb->s_flags &= ~MS_RDONLY;
2175 	}
2176 #ifdef CONFIG_QUOTA
2177 	/* Needed for iput() to work correctly and not trash data */
2178 	sb->s_flags |= MS_ACTIVE;
2179 	/* Turn on quotas so that they are updated correctly */
2180 	for (i = 0; i < MAXQUOTAS; i++) {
2181 		if (EXT4_SB(sb)->s_qf_names[i]) {
2182 			int ret = ext4_quota_on_mount(sb, i);
2183 			if (ret < 0)
2184 				ext4_msg(sb, KERN_ERR,
2185 					"Cannot turn on journaled "
2186 					"quota: error %d", ret);
2187 		}
2188 	}
2189 #endif
2190 
2191 	while (es->s_last_orphan) {
2192 		struct inode *inode;
2193 
2194 		inode = ext4_orphan_get(sb, le32_to_cpu(es->s_last_orphan));
2195 		if (IS_ERR(inode)) {
2196 			es->s_last_orphan = 0;
2197 			break;
2198 		}
2199 
2200 		list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
2201 		dquot_initialize(inode);
2202 		if (inode->i_nlink) {
2203 			ext4_msg(sb, KERN_DEBUG,
2204 				"%s: truncating inode %lu to %lld bytes",
2205 				__func__, inode->i_ino, inode->i_size);
2206 			jbd_debug(2, "truncating inode %lu to %lld bytes\n",
2207 				  inode->i_ino, inode->i_size);
2208 			ext4_truncate(inode);
2209 			nr_truncates++;
2210 		} else {
2211 			ext4_msg(sb, KERN_DEBUG,
2212 				"%s: deleting unreferenced inode %lu",
2213 				__func__, inode->i_ino);
2214 			jbd_debug(2, "deleting unreferenced inode %lu\n",
2215 				  inode->i_ino);
2216 			nr_orphans++;
2217 		}
2218 		iput(inode);  /* The delete magic happens here! */
2219 	}
2220 
2221 #define PLURAL(x) (x), ((x) == 1) ? "" : "s"
2222 
2223 	if (nr_orphans)
2224 		ext4_msg(sb, KERN_INFO, "%d orphan inode%s deleted",
2225 		       PLURAL(nr_orphans));
2226 	if (nr_truncates)
2227 		ext4_msg(sb, KERN_INFO, "%d truncate%s cleaned up",
2228 		       PLURAL(nr_truncates));
2229 #ifdef CONFIG_QUOTA
2230 	/* Turn quotas off */
2231 	for (i = 0; i < MAXQUOTAS; i++) {
2232 		if (sb_dqopt(sb)->files[i])
2233 			dquot_quota_off(sb, i);
2234 	}
2235 #endif
2236 	sb->s_flags = s_flags; /* Restore MS_RDONLY status */
2237 }
2238 
2239 /*
2240  * Maximal extent format file size.
2241  * Resulting logical blkno at s_maxbytes must fit in our on-disk
2242  * extent format containers, within a sector_t, and within i_blocks
2243  * in the vfs.  ext4 inode has 48 bits of i_block in fsblock units,
2244  * so that won't be a limiting factor.
2245  *
2246  * However there is other limiting factor. We do store extents in the form
2247  * of starting block and length, hence the resulting length of the extent
2248  * covering maximum file size must fit into on-disk format containers as
2249  * well. Given that length is always by 1 unit bigger than max unit (because
2250  * we count 0 as well) we have to lower the s_maxbytes by one fs block.
2251  *
2252  * Note, this does *not* consider any metadata overhead for vfs i_blocks.
2253  */
2254 static loff_t ext4_max_size(int blkbits, int has_huge_files)
2255 {
2256 	loff_t res;
2257 	loff_t upper_limit = MAX_LFS_FILESIZE;
2258 
2259 	/* small i_blocks in vfs inode? */
2260 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2261 		/*
2262 		 * CONFIG_LBDAF is not enabled implies the inode
2263 		 * i_block represent total blocks in 512 bytes
2264 		 * 32 == size of vfs inode i_blocks * 8
2265 		 */
2266 		upper_limit = (1LL << 32) - 1;
2267 
2268 		/* total blocks in file system block size */
2269 		upper_limit >>= (blkbits - 9);
2270 		upper_limit <<= blkbits;
2271 	}
2272 
2273 	/*
2274 	 * 32-bit extent-start container, ee_block. We lower the maxbytes
2275 	 * by one fs block, so ee_len can cover the extent of maximum file
2276 	 * size
2277 	 */
2278 	res = (1LL << 32) - 1;
2279 	res <<= blkbits;
2280 
2281 	/* Sanity check against vm- & vfs- imposed limits */
2282 	if (res > upper_limit)
2283 		res = upper_limit;
2284 
2285 	return res;
2286 }
2287 
2288 /*
2289  * Maximal bitmap file size.  There is a direct, and {,double-,triple-}indirect
2290  * block limit, and also a limit of (2^48 - 1) 512-byte sectors in i_blocks.
2291  * We need to be 1 filesystem block less than the 2^48 sector limit.
2292  */
2293 static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
2294 {
2295 	loff_t res = EXT4_NDIR_BLOCKS;
2296 	int meta_blocks;
2297 	loff_t upper_limit;
2298 	/* This is calculated to be the largest file size for a dense, block
2299 	 * mapped file such that the file's total number of 512-byte sectors,
2300 	 * including data and all indirect blocks, does not exceed (2^48 - 1).
2301 	 *
2302 	 * __u32 i_blocks_lo and _u16 i_blocks_high represent the total
2303 	 * number of 512-byte sectors of the file.
2304 	 */
2305 
2306 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2307 		/*
2308 		 * !has_huge_files or CONFIG_LBDAF not enabled implies that
2309 		 * the inode i_block field represents total file blocks in
2310 		 * 2^32 512-byte sectors == size of vfs inode i_blocks * 8
2311 		 */
2312 		upper_limit = (1LL << 32) - 1;
2313 
2314 		/* total blocks in file system block size */
2315 		upper_limit >>= (bits - 9);
2316 
2317 	} else {
2318 		/*
2319 		 * We use 48 bit ext4_inode i_blocks
2320 		 * With EXT4_HUGE_FILE_FL set the i_blocks
2321 		 * represent total number of blocks in
2322 		 * file system block size
2323 		 */
2324 		upper_limit = (1LL << 48) - 1;
2325 
2326 	}
2327 
2328 	/* indirect blocks */
2329 	meta_blocks = 1;
2330 	/* double indirect blocks */
2331 	meta_blocks += 1 + (1LL << (bits-2));
2332 	/* tripple indirect blocks */
2333 	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
2334 
2335 	upper_limit -= meta_blocks;
2336 	upper_limit <<= bits;
2337 
2338 	res += 1LL << (bits-2);
2339 	res += 1LL << (2*(bits-2));
2340 	res += 1LL << (3*(bits-2));
2341 	res <<= bits;
2342 	if (res > upper_limit)
2343 		res = upper_limit;
2344 
2345 	if (res > MAX_LFS_FILESIZE)
2346 		res = MAX_LFS_FILESIZE;
2347 
2348 	return res;
2349 }
2350 
2351 static ext4_fsblk_t descriptor_loc(struct super_block *sb,
2352 				   ext4_fsblk_t logical_sb_block, int nr)
2353 {
2354 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2355 	ext4_group_t bg, first_meta_bg;
2356 	int has_super = 0;
2357 
2358 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
2359 
2360 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
2361 	    nr < first_meta_bg)
2362 		return logical_sb_block + nr + 1;
2363 	bg = sbi->s_desc_per_block * nr;
2364 	if (ext4_bg_has_super(sb, bg))
2365 		has_super = 1;
2366 
2367 	return (has_super + ext4_group_first_block_no(sb, bg));
2368 }
2369 
2370 /**
2371  * ext4_get_stripe_size: Get the stripe size.
2372  * @sbi: In memory super block info
2373  *
2374  * If we have specified it via mount option, then
2375  * use the mount option value. If the value specified at mount time is
2376  * greater than the blocks per group use the super block value.
2377  * If the super block value is greater than blocks per group return 0.
2378  * Allocator needs it be less than blocks per group.
2379  *
2380  */
2381 static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi)
2382 {
2383 	unsigned long stride = le16_to_cpu(sbi->s_es->s_raid_stride);
2384 	unsigned long stripe_width =
2385 			le32_to_cpu(sbi->s_es->s_raid_stripe_width);
2386 
2387 	if (sbi->s_stripe && sbi->s_stripe <= sbi->s_blocks_per_group)
2388 		return sbi->s_stripe;
2389 
2390 	if (stripe_width <= sbi->s_blocks_per_group)
2391 		return stripe_width;
2392 
2393 	if (stride <= sbi->s_blocks_per_group)
2394 		return stride;
2395 
2396 	return 0;
2397 }
2398 
2399 /* sysfs supprt */
2400 
2401 struct ext4_attr {
2402 	struct attribute attr;
2403 	ssize_t (*show)(struct ext4_attr *, struct ext4_sb_info *, char *);
2404 	ssize_t (*store)(struct ext4_attr *, struct ext4_sb_info *,
2405 			 const char *, size_t);
2406 	int offset;
2407 };
2408 
2409 static int parse_strtoul(const char *buf,
2410 		unsigned long max, unsigned long *value)
2411 {
2412 	char *endp;
2413 
2414 	*value = simple_strtoul(skip_spaces(buf), &endp, 0);
2415 	endp = skip_spaces(endp);
2416 	if (*endp || *value > max)
2417 		return -EINVAL;
2418 
2419 	return 0;
2420 }
2421 
2422 static ssize_t delayed_allocation_blocks_show(struct ext4_attr *a,
2423 					      struct ext4_sb_info *sbi,
2424 					      char *buf)
2425 {
2426 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2427 			(s64) percpu_counter_sum(&sbi->s_dirtyblocks_counter));
2428 }
2429 
2430 static ssize_t session_write_kbytes_show(struct ext4_attr *a,
2431 					 struct ext4_sb_info *sbi, char *buf)
2432 {
2433 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
2434 
2435 	if (!sb->s_bdev->bd_part)
2436 		return snprintf(buf, PAGE_SIZE, "0\n");
2437 	return snprintf(buf, PAGE_SIZE, "%lu\n",
2438 			(part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
2439 			 sbi->s_sectors_written_start) >> 1);
2440 }
2441 
2442 static ssize_t lifetime_write_kbytes_show(struct ext4_attr *a,
2443 					  struct ext4_sb_info *sbi, char *buf)
2444 {
2445 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
2446 
2447 	if (!sb->s_bdev->bd_part)
2448 		return snprintf(buf, PAGE_SIZE, "0\n");
2449 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2450 			(unsigned long long)(sbi->s_kbytes_written +
2451 			((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
2452 			  EXT4_SB(sb)->s_sectors_written_start) >> 1)));
2453 }
2454 
2455 static ssize_t extent_cache_hits_show(struct ext4_attr *a,
2456 				      struct ext4_sb_info *sbi, char *buf)
2457 {
2458 	return snprintf(buf, PAGE_SIZE, "%lu\n", sbi->extent_cache_hits);
2459 }
2460 
2461 static ssize_t extent_cache_misses_show(struct ext4_attr *a,
2462 					struct ext4_sb_info *sbi, char *buf)
2463 {
2464 	return snprintf(buf, PAGE_SIZE, "%lu\n", sbi->extent_cache_misses);
2465 }
2466 
2467 static ssize_t inode_readahead_blks_store(struct ext4_attr *a,
2468 					  struct ext4_sb_info *sbi,
2469 					  const char *buf, size_t count)
2470 {
2471 	unsigned long t;
2472 
2473 	if (parse_strtoul(buf, 0x40000000, &t))
2474 		return -EINVAL;
2475 
2476 	if (t && !is_power_of_2(t))
2477 		return -EINVAL;
2478 
2479 	sbi->s_inode_readahead_blks = t;
2480 	return count;
2481 }
2482 
2483 static ssize_t sbi_ui_show(struct ext4_attr *a,
2484 			   struct ext4_sb_info *sbi, char *buf)
2485 {
2486 	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
2487 
2488 	return snprintf(buf, PAGE_SIZE, "%u\n", *ui);
2489 }
2490 
2491 static ssize_t sbi_ui_store(struct ext4_attr *a,
2492 			    struct ext4_sb_info *sbi,
2493 			    const char *buf, size_t count)
2494 {
2495 	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
2496 	unsigned long t;
2497 
2498 	if (parse_strtoul(buf, 0xffffffff, &t))
2499 		return -EINVAL;
2500 	*ui = t;
2501 	return count;
2502 }
2503 
2504 #define EXT4_ATTR_OFFSET(_name,_mode,_show,_store,_elname) \
2505 static struct ext4_attr ext4_attr_##_name = {			\
2506 	.attr = {.name = __stringify(_name), .mode = _mode },	\
2507 	.show	= _show,					\
2508 	.store	= _store,					\
2509 	.offset = offsetof(struct ext4_sb_info, _elname),	\
2510 }
2511 #define EXT4_ATTR(name, mode, show, store) \
2512 static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store)
2513 
2514 #define EXT4_INFO_ATTR(name) EXT4_ATTR(name, 0444, NULL, NULL)
2515 #define EXT4_RO_ATTR(name) EXT4_ATTR(name, 0444, name##_show, NULL)
2516 #define EXT4_RW_ATTR(name) EXT4_ATTR(name, 0644, name##_show, name##_store)
2517 #define EXT4_RW_ATTR_SBI_UI(name, elname)	\
2518 	EXT4_ATTR_OFFSET(name, 0644, sbi_ui_show, sbi_ui_store, elname)
2519 #define ATTR_LIST(name) &ext4_attr_##name.attr
2520 
2521 EXT4_RO_ATTR(delayed_allocation_blocks);
2522 EXT4_RO_ATTR(session_write_kbytes);
2523 EXT4_RO_ATTR(lifetime_write_kbytes);
2524 EXT4_RO_ATTR(extent_cache_hits);
2525 EXT4_RO_ATTR(extent_cache_misses);
2526 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, sbi_ui_show,
2527 		 inode_readahead_blks_store, s_inode_readahead_blks);
2528 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
2529 EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
2530 EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
2531 EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
2532 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
2533 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
2534 EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
2535 EXT4_RW_ATTR_SBI_UI(max_writeback_mb_bump, s_max_writeback_mb_bump);
2536 
2537 static struct attribute *ext4_attrs[] = {
2538 	ATTR_LIST(delayed_allocation_blocks),
2539 	ATTR_LIST(session_write_kbytes),
2540 	ATTR_LIST(lifetime_write_kbytes),
2541 	ATTR_LIST(extent_cache_hits),
2542 	ATTR_LIST(extent_cache_misses),
2543 	ATTR_LIST(inode_readahead_blks),
2544 	ATTR_LIST(inode_goal),
2545 	ATTR_LIST(mb_stats),
2546 	ATTR_LIST(mb_max_to_scan),
2547 	ATTR_LIST(mb_min_to_scan),
2548 	ATTR_LIST(mb_order2_req),
2549 	ATTR_LIST(mb_stream_req),
2550 	ATTR_LIST(mb_group_prealloc),
2551 	ATTR_LIST(max_writeback_mb_bump),
2552 	NULL,
2553 };
2554 
2555 /* Features this copy of ext4 supports */
2556 EXT4_INFO_ATTR(lazy_itable_init);
2557 EXT4_INFO_ATTR(batched_discard);
2558 
2559 static struct attribute *ext4_feat_attrs[] = {
2560 	ATTR_LIST(lazy_itable_init),
2561 	ATTR_LIST(batched_discard),
2562 	NULL,
2563 };
2564 
2565 static ssize_t ext4_attr_show(struct kobject *kobj,
2566 			      struct attribute *attr, char *buf)
2567 {
2568 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2569 						s_kobj);
2570 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
2571 
2572 	return a->show ? a->show(a, sbi, buf) : 0;
2573 }
2574 
2575 static ssize_t ext4_attr_store(struct kobject *kobj,
2576 			       struct attribute *attr,
2577 			       const char *buf, size_t len)
2578 {
2579 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2580 						s_kobj);
2581 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
2582 
2583 	return a->store ? a->store(a, sbi, buf, len) : 0;
2584 }
2585 
2586 static void ext4_sb_release(struct kobject *kobj)
2587 {
2588 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2589 						s_kobj);
2590 	complete(&sbi->s_kobj_unregister);
2591 }
2592 
2593 static const struct sysfs_ops ext4_attr_ops = {
2594 	.show	= ext4_attr_show,
2595 	.store	= ext4_attr_store,
2596 };
2597 
2598 static struct kobj_type ext4_ktype = {
2599 	.default_attrs	= ext4_attrs,
2600 	.sysfs_ops	= &ext4_attr_ops,
2601 	.release	= ext4_sb_release,
2602 };
2603 
2604 static void ext4_feat_release(struct kobject *kobj)
2605 {
2606 	complete(&ext4_feat->f_kobj_unregister);
2607 }
2608 
2609 static struct kobj_type ext4_feat_ktype = {
2610 	.default_attrs	= ext4_feat_attrs,
2611 	.sysfs_ops	= &ext4_attr_ops,
2612 	.release	= ext4_feat_release,
2613 };
2614 
2615 /*
2616  * Check whether this filesystem can be mounted based on
2617  * the features present and the RDONLY/RDWR mount requested.
2618  * Returns 1 if this filesystem can be mounted as requested,
2619  * 0 if it cannot be.
2620  */
2621 static int ext4_feature_set_ok(struct super_block *sb, int readonly)
2622 {
2623 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT4_FEATURE_INCOMPAT_SUPP)) {
2624 		ext4_msg(sb, KERN_ERR,
2625 			"Couldn't mount because of "
2626 			"unsupported optional features (%x)",
2627 			(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_incompat) &
2628 			~EXT4_FEATURE_INCOMPAT_SUPP));
2629 		return 0;
2630 	}
2631 
2632 	if (readonly)
2633 		return 1;
2634 
2635 	/* Check that feature set is OK for a read-write mount */
2636 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT4_FEATURE_RO_COMPAT_SUPP)) {
2637 		ext4_msg(sb, KERN_ERR, "couldn't mount RDWR because of "
2638 			 "unsupported optional features (%x)",
2639 			 (le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_ro_compat) &
2640 				~EXT4_FEATURE_RO_COMPAT_SUPP));
2641 		return 0;
2642 	}
2643 	/*
2644 	 * Large file size enabled file system can only be mounted
2645 	 * read-write on 32-bit systems if kernel is built with CONFIG_LBDAF
2646 	 */
2647 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
2648 		if (sizeof(blkcnt_t) < sizeof(u64)) {
2649 			ext4_msg(sb, KERN_ERR, "Filesystem with huge files "
2650 				 "cannot be mounted RDWR without "
2651 				 "CONFIG_LBDAF");
2652 			return 0;
2653 		}
2654 	}
2655 	return 1;
2656 }
2657 
2658 /*
2659  * This function is called once a day if we have errors logged
2660  * on the file system
2661  */
2662 static void print_daily_error_info(unsigned long arg)
2663 {
2664 	struct super_block *sb = (struct super_block *) arg;
2665 	struct ext4_sb_info *sbi;
2666 	struct ext4_super_block *es;
2667 
2668 	sbi = EXT4_SB(sb);
2669 	es = sbi->s_es;
2670 
2671 	if (es->s_error_count)
2672 		ext4_msg(sb, KERN_NOTICE, "error count: %u",
2673 			 le32_to_cpu(es->s_error_count));
2674 	if (es->s_first_error_time) {
2675 		printk(KERN_NOTICE "EXT4-fs (%s): initial error at %u: %.*s:%d",
2676 		       sb->s_id, le32_to_cpu(es->s_first_error_time),
2677 		       (int) sizeof(es->s_first_error_func),
2678 		       es->s_first_error_func,
2679 		       le32_to_cpu(es->s_first_error_line));
2680 		if (es->s_first_error_ino)
2681 			printk(": inode %u",
2682 			       le32_to_cpu(es->s_first_error_ino));
2683 		if (es->s_first_error_block)
2684 			printk(": block %llu", (unsigned long long)
2685 			       le64_to_cpu(es->s_first_error_block));
2686 		printk("\n");
2687 	}
2688 	if (es->s_last_error_time) {
2689 		printk(KERN_NOTICE "EXT4-fs (%s): last error at %u: %.*s:%d",
2690 		       sb->s_id, le32_to_cpu(es->s_last_error_time),
2691 		       (int) sizeof(es->s_last_error_func),
2692 		       es->s_last_error_func,
2693 		       le32_to_cpu(es->s_last_error_line));
2694 		if (es->s_last_error_ino)
2695 			printk(": inode %u",
2696 			       le32_to_cpu(es->s_last_error_ino));
2697 		if (es->s_last_error_block)
2698 			printk(": block %llu", (unsigned long long)
2699 			       le64_to_cpu(es->s_last_error_block));
2700 		printk("\n");
2701 	}
2702 	mod_timer(&sbi->s_err_report, jiffies + 24*60*60*HZ);  /* Once a day */
2703 }
2704 
2705 /* Find next suitable group and run ext4_init_inode_table */
2706 static int ext4_run_li_request(struct ext4_li_request *elr)
2707 {
2708 	struct ext4_group_desc *gdp = NULL;
2709 	ext4_group_t group, ngroups;
2710 	struct super_block *sb;
2711 	unsigned long timeout = 0;
2712 	int ret = 0;
2713 
2714 	sb = elr->lr_super;
2715 	ngroups = EXT4_SB(sb)->s_groups_count;
2716 
2717 	for (group = elr->lr_next_group; group < ngroups; group++) {
2718 		gdp = ext4_get_group_desc(sb, group, NULL);
2719 		if (!gdp) {
2720 			ret = 1;
2721 			break;
2722 		}
2723 
2724 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2725 			break;
2726 	}
2727 
2728 	if (group == ngroups)
2729 		ret = 1;
2730 
2731 	if (!ret) {
2732 		timeout = jiffies;
2733 		ret = ext4_init_inode_table(sb, group,
2734 					    elr->lr_timeout ? 0 : 1);
2735 		if (elr->lr_timeout == 0) {
2736 			timeout = (jiffies - timeout) *
2737 				  elr->lr_sbi->s_li_wait_mult;
2738 			elr->lr_timeout = timeout;
2739 		}
2740 		elr->lr_next_sched = jiffies + elr->lr_timeout;
2741 		elr->lr_next_group = group + 1;
2742 	}
2743 
2744 	return ret;
2745 }
2746 
2747 /*
2748  * Remove lr_request from the list_request and free the
2749  * request structure. Should be called with li_list_mtx held
2750  */
2751 static void ext4_remove_li_request(struct ext4_li_request *elr)
2752 {
2753 	struct ext4_sb_info *sbi;
2754 
2755 	if (!elr)
2756 		return;
2757 
2758 	sbi = elr->lr_sbi;
2759 
2760 	list_del(&elr->lr_request);
2761 	sbi->s_li_request = NULL;
2762 	kfree(elr);
2763 }
2764 
2765 static void ext4_unregister_li_request(struct super_block *sb)
2766 {
2767 	mutex_lock(&ext4_li_mtx);
2768 	if (!ext4_li_info) {
2769 		mutex_unlock(&ext4_li_mtx);
2770 		return;
2771 	}
2772 
2773 	mutex_lock(&ext4_li_info->li_list_mtx);
2774 	ext4_remove_li_request(EXT4_SB(sb)->s_li_request);
2775 	mutex_unlock(&ext4_li_info->li_list_mtx);
2776 	mutex_unlock(&ext4_li_mtx);
2777 }
2778 
2779 static struct task_struct *ext4_lazyinit_task;
2780 
2781 /*
2782  * This is the function where ext4lazyinit thread lives. It walks
2783  * through the request list searching for next scheduled filesystem.
2784  * When such a fs is found, run the lazy initialization request
2785  * (ext4_rn_li_request) and keep track of the time spend in this
2786  * function. Based on that time we compute next schedule time of
2787  * the request. When walking through the list is complete, compute
2788  * next waking time and put itself into sleep.
2789  */
2790 static int ext4_lazyinit_thread(void *arg)
2791 {
2792 	struct ext4_lazy_init *eli = (struct ext4_lazy_init *)arg;
2793 	struct list_head *pos, *n;
2794 	struct ext4_li_request *elr;
2795 	unsigned long next_wakeup, cur;
2796 
2797 	BUG_ON(NULL == eli);
2798 
2799 cont_thread:
2800 	while (true) {
2801 		next_wakeup = MAX_JIFFY_OFFSET;
2802 
2803 		mutex_lock(&eli->li_list_mtx);
2804 		if (list_empty(&eli->li_request_list)) {
2805 			mutex_unlock(&eli->li_list_mtx);
2806 			goto exit_thread;
2807 		}
2808 
2809 		list_for_each_safe(pos, n, &eli->li_request_list) {
2810 			elr = list_entry(pos, struct ext4_li_request,
2811 					 lr_request);
2812 
2813 			if (time_after_eq(jiffies, elr->lr_next_sched)) {
2814 				if (ext4_run_li_request(elr) != 0) {
2815 					/* error, remove the lazy_init job */
2816 					ext4_remove_li_request(elr);
2817 					continue;
2818 				}
2819 			}
2820 
2821 			if (time_before(elr->lr_next_sched, next_wakeup))
2822 				next_wakeup = elr->lr_next_sched;
2823 		}
2824 		mutex_unlock(&eli->li_list_mtx);
2825 
2826 		if (freezing(current))
2827 			refrigerator();
2828 
2829 		cur = jiffies;
2830 		if ((time_after_eq(cur, next_wakeup)) ||
2831 		    (MAX_JIFFY_OFFSET == next_wakeup)) {
2832 			cond_resched();
2833 			continue;
2834 		}
2835 
2836 		schedule_timeout_interruptible(next_wakeup - cur);
2837 
2838 		if (kthread_should_stop()) {
2839 			ext4_clear_request_list();
2840 			goto exit_thread;
2841 		}
2842 	}
2843 
2844 exit_thread:
2845 	/*
2846 	 * It looks like the request list is empty, but we need
2847 	 * to check it under the li_list_mtx lock, to prevent any
2848 	 * additions into it, and of course we should lock ext4_li_mtx
2849 	 * to atomically free the list and ext4_li_info, because at
2850 	 * this point another ext4 filesystem could be registering
2851 	 * new one.
2852 	 */
2853 	mutex_lock(&ext4_li_mtx);
2854 	mutex_lock(&eli->li_list_mtx);
2855 	if (!list_empty(&eli->li_request_list)) {
2856 		mutex_unlock(&eli->li_list_mtx);
2857 		mutex_unlock(&ext4_li_mtx);
2858 		goto cont_thread;
2859 	}
2860 	mutex_unlock(&eli->li_list_mtx);
2861 	kfree(ext4_li_info);
2862 	ext4_li_info = NULL;
2863 	mutex_unlock(&ext4_li_mtx);
2864 
2865 	return 0;
2866 }
2867 
2868 static void ext4_clear_request_list(void)
2869 {
2870 	struct list_head *pos, *n;
2871 	struct ext4_li_request *elr;
2872 
2873 	mutex_lock(&ext4_li_info->li_list_mtx);
2874 	list_for_each_safe(pos, n, &ext4_li_info->li_request_list) {
2875 		elr = list_entry(pos, struct ext4_li_request,
2876 				 lr_request);
2877 		ext4_remove_li_request(elr);
2878 	}
2879 	mutex_unlock(&ext4_li_info->li_list_mtx);
2880 }
2881 
2882 static int ext4_run_lazyinit_thread(void)
2883 {
2884 	ext4_lazyinit_task = kthread_run(ext4_lazyinit_thread,
2885 					 ext4_li_info, "ext4lazyinit");
2886 	if (IS_ERR(ext4_lazyinit_task)) {
2887 		int err = PTR_ERR(ext4_lazyinit_task);
2888 		ext4_clear_request_list();
2889 		kfree(ext4_li_info);
2890 		ext4_li_info = NULL;
2891 		printk(KERN_CRIT "EXT4: error %d creating inode table "
2892 				 "initialization thread\n",
2893 				 err);
2894 		return err;
2895 	}
2896 	ext4_li_info->li_state |= EXT4_LAZYINIT_RUNNING;
2897 	return 0;
2898 }
2899 
2900 /*
2901  * Check whether it make sense to run itable init. thread or not.
2902  * If there is at least one uninitialized inode table, return
2903  * corresponding group number, else the loop goes through all
2904  * groups and return total number of groups.
2905  */
2906 static ext4_group_t ext4_has_uninit_itable(struct super_block *sb)
2907 {
2908 	ext4_group_t group, ngroups = EXT4_SB(sb)->s_groups_count;
2909 	struct ext4_group_desc *gdp = NULL;
2910 
2911 	for (group = 0; group < ngroups; group++) {
2912 		gdp = ext4_get_group_desc(sb, group, NULL);
2913 		if (!gdp)
2914 			continue;
2915 
2916 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2917 			break;
2918 	}
2919 
2920 	return group;
2921 }
2922 
2923 static int ext4_li_info_new(void)
2924 {
2925 	struct ext4_lazy_init *eli = NULL;
2926 
2927 	eli = kzalloc(sizeof(*eli), GFP_KERNEL);
2928 	if (!eli)
2929 		return -ENOMEM;
2930 
2931 	INIT_LIST_HEAD(&eli->li_request_list);
2932 	mutex_init(&eli->li_list_mtx);
2933 
2934 	eli->li_state |= EXT4_LAZYINIT_QUIT;
2935 
2936 	ext4_li_info = eli;
2937 
2938 	return 0;
2939 }
2940 
2941 static struct ext4_li_request *ext4_li_request_new(struct super_block *sb,
2942 					    ext4_group_t start)
2943 {
2944 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2945 	struct ext4_li_request *elr;
2946 	unsigned long rnd;
2947 
2948 	elr = kzalloc(sizeof(*elr), GFP_KERNEL);
2949 	if (!elr)
2950 		return NULL;
2951 
2952 	elr->lr_super = sb;
2953 	elr->lr_sbi = sbi;
2954 	elr->lr_next_group = start;
2955 
2956 	/*
2957 	 * Randomize first schedule time of the request to
2958 	 * spread the inode table initialization requests
2959 	 * better.
2960 	 */
2961 	get_random_bytes(&rnd, sizeof(rnd));
2962 	elr->lr_next_sched = jiffies + (unsigned long)rnd %
2963 			     (EXT4_DEF_LI_MAX_START_DELAY * HZ);
2964 
2965 	return elr;
2966 }
2967 
2968 static int ext4_register_li_request(struct super_block *sb,
2969 				    ext4_group_t first_not_zeroed)
2970 {
2971 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2972 	struct ext4_li_request *elr;
2973 	ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
2974 	int ret = 0;
2975 
2976 	if (sbi->s_li_request != NULL) {
2977 		/*
2978 		 * Reset timeout so it can be computed again, because
2979 		 * s_li_wait_mult might have changed.
2980 		 */
2981 		sbi->s_li_request->lr_timeout = 0;
2982 		return 0;
2983 	}
2984 
2985 	if (first_not_zeroed == ngroups ||
2986 	    (sb->s_flags & MS_RDONLY) ||
2987 	    !test_opt(sb, INIT_INODE_TABLE))
2988 		return 0;
2989 
2990 	elr = ext4_li_request_new(sb, first_not_zeroed);
2991 	if (!elr)
2992 		return -ENOMEM;
2993 
2994 	mutex_lock(&ext4_li_mtx);
2995 
2996 	if (NULL == ext4_li_info) {
2997 		ret = ext4_li_info_new();
2998 		if (ret)
2999 			goto out;
3000 	}
3001 
3002 	mutex_lock(&ext4_li_info->li_list_mtx);
3003 	list_add(&elr->lr_request, &ext4_li_info->li_request_list);
3004 	mutex_unlock(&ext4_li_info->li_list_mtx);
3005 
3006 	sbi->s_li_request = elr;
3007 	/*
3008 	 * set elr to NULL here since it has been inserted to
3009 	 * the request_list and the removal and free of it is
3010 	 * handled by ext4_clear_request_list from now on.
3011 	 */
3012 	elr = NULL;
3013 
3014 	if (!(ext4_li_info->li_state & EXT4_LAZYINIT_RUNNING)) {
3015 		ret = ext4_run_lazyinit_thread();
3016 		if (ret)
3017 			goto out;
3018 	}
3019 out:
3020 	mutex_unlock(&ext4_li_mtx);
3021 	if (ret)
3022 		kfree(elr);
3023 	return ret;
3024 }
3025 
3026 /*
3027  * We do not need to lock anything since this is called on
3028  * module unload.
3029  */
3030 static void ext4_destroy_lazyinit_thread(void)
3031 {
3032 	/*
3033 	 * If thread exited earlier
3034 	 * there's nothing to be done.
3035 	 */
3036 	if (!ext4_li_info || !ext4_lazyinit_task)
3037 		return;
3038 
3039 	kthread_stop(ext4_lazyinit_task);
3040 }
3041 
3042 static int ext4_fill_super(struct super_block *sb, void *data, int silent)
3043 				__releases(kernel_lock)
3044 				__acquires(kernel_lock)
3045 {
3046 	char *orig_data = kstrdup(data, GFP_KERNEL);
3047 	struct buffer_head *bh;
3048 	struct ext4_super_block *es = NULL;
3049 	struct ext4_sb_info *sbi;
3050 	ext4_fsblk_t block;
3051 	ext4_fsblk_t sb_block = get_sb_block(&data);
3052 	ext4_fsblk_t logical_sb_block;
3053 	unsigned long offset = 0;
3054 	unsigned long journal_devnum = 0;
3055 	unsigned long def_mount_opts;
3056 	struct inode *root;
3057 	char *cp;
3058 	const char *descr;
3059 	int ret = -ENOMEM;
3060 	int blocksize;
3061 	unsigned int db_count;
3062 	unsigned int i;
3063 	int needs_recovery, has_huge_files;
3064 	__u64 blocks_count;
3065 	int err;
3066 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
3067 	ext4_group_t first_not_zeroed;
3068 
3069 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
3070 	if (!sbi)
3071 		goto out_free_orig;
3072 
3073 	sbi->s_blockgroup_lock =
3074 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
3075 	if (!sbi->s_blockgroup_lock) {
3076 		kfree(sbi);
3077 		goto out_free_orig;
3078 	}
3079 	sb->s_fs_info = sbi;
3080 	sbi->s_mount_opt = 0;
3081 	sbi->s_resuid = EXT4_DEF_RESUID;
3082 	sbi->s_resgid = EXT4_DEF_RESGID;
3083 	sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
3084 	sbi->s_sb_block = sb_block;
3085 	if (sb->s_bdev->bd_part)
3086 		sbi->s_sectors_written_start =
3087 			part_stat_read(sb->s_bdev->bd_part, sectors[1]);
3088 
3089 	/* Cleanup superblock name */
3090 	for (cp = sb->s_id; (cp = strchr(cp, '/'));)
3091 		*cp = '!';
3092 
3093 	ret = -EINVAL;
3094 	blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
3095 	if (!blocksize) {
3096 		ext4_msg(sb, KERN_ERR, "unable to set blocksize");
3097 		goto out_fail;
3098 	}
3099 
3100 	/*
3101 	 * The ext4 superblock will not be buffer aligned for other than 1kB
3102 	 * block sizes.  We need to calculate the offset from buffer start.
3103 	 */
3104 	if (blocksize != EXT4_MIN_BLOCK_SIZE) {
3105 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3106 		offset = do_div(logical_sb_block, blocksize);
3107 	} else {
3108 		logical_sb_block = sb_block;
3109 	}
3110 
3111 	if (!(bh = sb_bread(sb, logical_sb_block))) {
3112 		ext4_msg(sb, KERN_ERR, "unable to read superblock");
3113 		goto out_fail;
3114 	}
3115 	/*
3116 	 * Note: s_es must be initialized as soon as possible because
3117 	 *       some ext4 macro-instructions depend on its value
3118 	 */
3119 	es = (struct ext4_super_block *) (((char *)bh->b_data) + offset);
3120 	sbi->s_es = es;
3121 	sb->s_magic = le16_to_cpu(es->s_magic);
3122 	if (sb->s_magic != EXT4_SUPER_MAGIC)
3123 		goto cantfind_ext4;
3124 	sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
3125 
3126 	/* Set defaults before we parse the mount options */
3127 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
3128 	set_opt(sb, INIT_INODE_TABLE);
3129 	if (def_mount_opts & EXT4_DEFM_DEBUG)
3130 		set_opt(sb, DEBUG);
3131 	if (def_mount_opts & EXT4_DEFM_BSDGROUPS) {
3132 		ext4_msg(sb, KERN_WARNING, deprecated_msg, "bsdgroups",
3133 			"2.6.38");
3134 		set_opt(sb, GRPID);
3135 	}
3136 	if (def_mount_opts & EXT4_DEFM_UID16)
3137 		set_opt(sb, NO_UID32);
3138 	/* xattr user namespace & acls are now defaulted on */
3139 #ifdef CONFIG_EXT4_FS_XATTR
3140 	set_opt(sb, XATTR_USER);
3141 #endif
3142 #ifdef CONFIG_EXT4_FS_POSIX_ACL
3143 	set_opt(sb, POSIX_ACL);
3144 #endif
3145 	set_opt(sb, MBLK_IO_SUBMIT);
3146 	if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA)
3147 		set_opt(sb, JOURNAL_DATA);
3148 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_ORDERED)
3149 		set_opt(sb, ORDERED_DATA);
3150 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_WBACK)
3151 		set_opt(sb, WRITEBACK_DATA);
3152 
3153 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_PANIC)
3154 		set_opt(sb, ERRORS_PANIC);
3155 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_CONTINUE)
3156 		set_opt(sb, ERRORS_CONT);
3157 	else
3158 		set_opt(sb, ERRORS_RO);
3159 	if (def_mount_opts & EXT4_DEFM_BLOCK_VALIDITY)
3160 		set_opt(sb, BLOCK_VALIDITY);
3161 	if (def_mount_opts & EXT4_DEFM_DISCARD)
3162 		set_opt(sb, DISCARD);
3163 
3164 	sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
3165 	sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
3166 	sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ;
3167 	sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;
3168 	sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;
3169 
3170 	if ((def_mount_opts & EXT4_DEFM_NOBARRIER) == 0)
3171 		set_opt(sb, BARRIER);
3172 
3173 	/*
3174 	 * enable delayed allocation by default
3175 	 * Use -o nodelalloc to turn it off
3176 	 */
3177 	if (!IS_EXT3_SB(sb) &&
3178 	    ((def_mount_opts & EXT4_DEFM_NODELALLOC) == 0))
3179 		set_opt(sb, DELALLOC);
3180 
3181 	/*
3182 	 * set default s_li_wait_mult for lazyinit, for the case there is
3183 	 * no mount option specified.
3184 	 */
3185 	sbi->s_li_wait_mult = EXT4_DEF_LI_WAIT_MULT;
3186 
3187 	if (!parse_options((char *) sbi->s_es->s_mount_opts, sb,
3188 			   &journal_devnum, &journal_ioprio, NULL, 0)) {
3189 		ext4_msg(sb, KERN_WARNING,
3190 			 "failed to parse options in superblock: %s",
3191 			 sbi->s_es->s_mount_opts);
3192 	}
3193 	if (!parse_options((char *) data, sb, &journal_devnum,
3194 			   &journal_ioprio, NULL, 0))
3195 		goto failed_mount;
3196 
3197 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
3198 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
3199 
3200 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
3201 	    (EXT4_HAS_COMPAT_FEATURE(sb, ~0U) ||
3202 	     EXT4_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
3203 	     EXT4_HAS_INCOMPAT_FEATURE(sb, ~0U)))
3204 		ext4_msg(sb, KERN_WARNING,
3205 		       "feature flags set on rev 0 fs, "
3206 		       "running e2fsck is recommended");
3207 
3208 	if (IS_EXT2_SB(sb)) {
3209 		if (ext2_feature_set_ok(sb))
3210 			ext4_msg(sb, KERN_INFO, "mounting ext2 file system "
3211 				 "using the ext4 subsystem");
3212 		else {
3213 			ext4_msg(sb, KERN_ERR, "couldn't mount as ext2 due "
3214 				 "to feature incompatibilities");
3215 			goto failed_mount;
3216 		}
3217 	}
3218 
3219 	if (IS_EXT3_SB(sb)) {
3220 		if (ext3_feature_set_ok(sb))
3221 			ext4_msg(sb, KERN_INFO, "mounting ext3 file system "
3222 				 "using the ext4 subsystem");
3223 		else {
3224 			ext4_msg(sb, KERN_ERR, "couldn't mount as ext3 due "
3225 				 "to feature incompatibilities");
3226 			goto failed_mount;
3227 		}
3228 	}
3229 
3230 	/*
3231 	 * Check feature flags regardless of the revision level, since we
3232 	 * previously didn't change the revision level when setting the flags,
3233 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
3234 	 */
3235 	if (!ext4_feature_set_ok(sb, (sb->s_flags & MS_RDONLY)))
3236 		goto failed_mount;
3237 
3238 	blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
3239 
3240 	if (blocksize < EXT4_MIN_BLOCK_SIZE ||
3241 	    blocksize > EXT4_MAX_BLOCK_SIZE) {
3242 		ext4_msg(sb, KERN_ERR,
3243 		       "Unsupported filesystem blocksize %d", blocksize);
3244 		goto failed_mount;
3245 	}
3246 
3247 	if (sb->s_blocksize != blocksize) {
3248 		/* Validate the filesystem blocksize */
3249 		if (!sb_set_blocksize(sb, blocksize)) {
3250 			ext4_msg(sb, KERN_ERR, "bad block size %d",
3251 					blocksize);
3252 			goto failed_mount;
3253 		}
3254 
3255 		brelse(bh);
3256 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3257 		offset = do_div(logical_sb_block, blocksize);
3258 		bh = sb_bread(sb, logical_sb_block);
3259 		if (!bh) {
3260 			ext4_msg(sb, KERN_ERR,
3261 			       "Can't read superblock on 2nd try");
3262 			goto failed_mount;
3263 		}
3264 		es = (struct ext4_super_block *)(((char *)bh->b_data) + offset);
3265 		sbi->s_es = es;
3266 		if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
3267 			ext4_msg(sb, KERN_ERR,
3268 			       "Magic mismatch, very weird!");
3269 			goto failed_mount;
3270 		}
3271 	}
3272 
3273 	has_huge_files = EXT4_HAS_RO_COMPAT_FEATURE(sb,
3274 				EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
3275 	sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits,
3276 						      has_huge_files);
3277 	sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits, has_huge_files);
3278 
3279 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) {
3280 		sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE;
3281 		sbi->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
3282 	} else {
3283 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
3284 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
3285 		if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
3286 		    (!is_power_of_2(sbi->s_inode_size)) ||
3287 		    (sbi->s_inode_size > blocksize)) {
3288 			ext4_msg(sb, KERN_ERR,
3289 			       "unsupported inode size: %d",
3290 			       sbi->s_inode_size);
3291 			goto failed_mount;
3292 		}
3293 		if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE)
3294 			sb->s_time_gran = 1 << (EXT4_EPOCH_BITS - 2);
3295 	}
3296 
3297 	sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
3298 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT)) {
3299 		if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT ||
3300 		    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
3301 		    !is_power_of_2(sbi->s_desc_size)) {
3302 			ext4_msg(sb, KERN_ERR,
3303 			       "unsupported descriptor size %lu",
3304 			       sbi->s_desc_size);
3305 			goto failed_mount;
3306 		}
3307 	} else
3308 		sbi->s_desc_size = EXT4_MIN_DESC_SIZE;
3309 
3310 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
3311 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
3312 	if (EXT4_INODE_SIZE(sb) == 0 || EXT4_INODES_PER_GROUP(sb) == 0)
3313 		goto cantfind_ext4;
3314 
3315 	sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
3316 	if (sbi->s_inodes_per_block == 0)
3317 		goto cantfind_ext4;
3318 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
3319 					sbi->s_inodes_per_block;
3320 	sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
3321 	sbi->s_sbh = bh;
3322 	sbi->s_mount_state = le16_to_cpu(es->s_state);
3323 	sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
3324 	sbi->s_desc_per_block_bits = ilog2(EXT4_DESC_PER_BLOCK(sb));
3325 
3326 	for (i = 0; i < 4; i++)
3327 		sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
3328 	sbi->s_def_hash_version = es->s_def_hash_version;
3329 	i = le32_to_cpu(es->s_flags);
3330 	if (i & EXT2_FLAGS_UNSIGNED_HASH)
3331 		sbi->s_hash_unsigned = 3;
3332 	else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) {
3333 #ifdef __CHAR_UNSIGNED__
3334 		es->s_flags |= cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH);
3335 		sbi->s_hash_unsigned = 3;
3336 #else
3337 		es->s_flags |= cpu_to_le32(EXT2_FLAGS_SIGNED_HASH);
3338 #endif
3339 		sb->s_dirt = 1;
3340 	}
3341 
3342 	if (sbi->s_blocks_per_group > blocksize * 8) {
3343 		ext4_msg(sb, KERN_ERR,
3344 		       "#blocks per group too big: %lu",
3345 		       sbi->s_blocks_per_group);
3346 		goto failed_mount;
3347 	}
3348 	if (sbi->s_inodes_per_group > blocksize * 8) {
3349 		ext4_msg(sb, KERN_ERR,
3350 		       "#inodes per group too big: %lu",
3351 		       sbi->s_inodes_per_group);
3352 		goto failed_mount;
3353 	}
3354 
3355 	/*
3356 	 * Test whether we have more sectors than will fit in sector_t,
3357 	 * and whether the max offset is addressable by the page cache.
3358 	 */
3359 	err = generic_check_addressable(sb->s_blocksize_bits,
3360 					ext4_blocks_count(es));
3361 	if (err) {
3362 		ext4_msg(sb, KERN_ERR, "filesystem"
3363 			 " too large to mount safely on this system");
3364 		if (sizeof(sector_t) < 8)
3365 			ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled");
3366 		ret = err;
3367 		goto failed_mount;
3368 	}
3369 
3370 	if (EXT4_BLOCKS_PER_GROUP(sb) == 0)
3371 		goto cantfind_ext4;
3372 
3373 	/* check blocks count against device size */
3374 	blocks_count = sb->s_bdev->bd_inode->i_size >> sb->s_blocksize_bits;
3375 	if (blocks_count && ext4_blocks_count(es) > blocks_count) {
3376 		ext4_msg(sb, KERN_WARNING, "bad geometry: block count %llu "
3377 		       "exceeds size of device (%llu blocks)",
3378 		       ext4_blocks_count(es), blocks_count);
3379 		goto failed_mount;
3380 	}
3381 
3382 	/*
3383 	 * It makes no sense for the first data block to be beyond the end
3384 	 * of the filesystem.
3385 	 */
3386 	if (le32_to_cpu(es->s_first_data_block) >= ext4_blocks_count(es)) {
3387                 ext4_msg(sb, KERN_WARNING, "bad geometry: first data"
3388 			 "block %u is beyond end of filesystem (%llu)",
3389 			 le32_to_cpu(es->s_first_data_block),
3390 			 ext4_blocks_count(es));
3391 		goto failed_mount;
3392 	}
3393 	blocks_count = (ext4_blocks_count(es) -
3394 			le32_to_cpu(es->s_first_data_block) +
3395 			EXT4_BLOCKS_PER_GROUP(sb) - 1);
3396 	do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
3397 	if (blocks_count > ((uint64_t)1<<32) - EXT4_DESC_PER_BLOCK(sb)) {
3398 		ext4_msg(sb, KERN_WARNING, "groups count too large: %u "
3399 		       "(block count %llu, first data block %u, "
3400 		       "blocks per group %lu)", sbi->s_groups_count,
3401 		       ext4_blocks_count(es),
3402 		       le32_to_cpu(es->s_first_data_block),
3403 		       EXT4_BLOCKS_PER_GROUP(sb));
3404 		goto failed_mount;
3405 	}
3406 	sbi->s_groups_count = blocks_count;
3407 	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
3408 			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
3409 	db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
3410 		   EXT4_DESC_PER_BLOCK(sb);
3411 	sbi->s_group_desc = kmalloc(db_count * sizeof(struct buffer_head *),
3412 				    GFP_KERNEL);
3413 	if (sbi->s_group_desc == NULL) {
3414 		ext4_msg(sb, KERN_ERR, "not enough memory");
3415 		goto failed_mount;
3416 	}
3417 
3418 #ifdef CONFIG_PROC_FS
3419 	if (ext4_proc_root)
3420 		sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
3421 #endif
3422 
3423 	bgl_lock_init(sbi->s_blockgroup_lock);
3424 
3425 	for (i = 0; i < db_count; i++) {
3426 		block = descriptor_loc(sb, logical_sb_block, i);
3427 		sbi->s_group_desc[i] = sb_bread(sb, block);
3428 		if (!sbi->s_group_desc[i]) {
3429 			ext4_msg(sb, KERN_ERR,
3430 			       "can't read group descriptor %d", i);
3431 			db_count = i;
3432 			goto failed_mount2;
3433 		}
3434 	}
3435 	if (!ext4_check_descriptors(sb, &first_not_zeroed)) {
3436 		ext4_msg(sb, KERN_ERR, "group descriptors corrupted!");
3437 		goto failed_mount2;
3438 	}
3439 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
3440 		if (!ext4_fill_flex_info(sb)) {
3441 			ext4_msg(sb, KERN_ERR,
3442 			       "unable to initialize "
3443 			       "flex_bg meta info!");
3444 			goto failed_mount2;
3445 		}
3446 
3447 	sbi->s_gdb_count = db_count;
3448 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
3449 	spin_lock_init(&sbi->s_next_gen_lock);
3450 
3451 	init_timer(&sbi->s_err_report);
3452 	sbi->s_err_report.function = print_daily_error_info;
3453 	sbi->s_err_report.data = (unsigned long) sb;
3454 
3455 	err = percpu_counter_init(&sbi->s_freeblocks_counter,
3456 			ext4_count_free_blocks(sb));
3457 	if (!err) {
3458 		err = percpu_counter_init(&sbi->s_freeinodes_counter,
3459 				ext4_count_free_inodes(sb));
3460 	}
3461 	if (!err) {
3462 		err = percpu_counter_init(&sbi->s_dirs_counter,
3463 				ext4_count_dirs(sb));
3464 	}
3465 	if (!err) {
3466 		err = percpu_counter_init(&sbi->s_dirtyblocks_counter, 0);
3467 	}
3468 	if (err) {
3469 		ext4_msg(sb, KERN_ERR, "insufficient memory");
3470 		goto failed_mount3;
3471 	}
3472 
3473 	sbi->s_stripe = ext4_get_stripe_size(sbi);
3474 	sbi->s_max_writeback_mb_bump = 128;
3475 
3476 	/*
3477 	 * set up enough so that it can read an inode
3478 	 */
3479 	if (!test_opt(sb, NOLOAD) &&
3480 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL))
3481 		sb->s_op = &ext4_sops;
3482 	else
3483 		sb->s_op = &ext4_nojournal_sops;
3484 	sb->s_export_op = &ext4_export_ops;
3485 	sb->s_xattr = ext4_xattr_handlers;
3486 #ifdef CONFIG_QUOTA
3487 	sb->s_qcop = &ext4_qctl_operations;
3488 	sb->dq_op = &ext4_quota_operations;
3489 #endif
3490 	memcpy(sb->s_uuid, es->s_uuid, sizeof(es->s_uuid));
3491 
3492 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
3493 	mutex_init(&sbi->s_orphan_lock);
3494 	mutex_init(&sbi->s_resize_lock);
3495 
3496 	sb->s_root = NULL;
3497 
3498 	needs_recovery = (es->s_last_orphan != 0 ||
3499 			  EXT4_HAS_INCOMPAT_FEATURE(sb,
3500 				    EXT4_FEATURE_INCOMPAT_RECOVER));
3501 
3502 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_MMP) &&
3503 	    !(sb->s_flags & MS_RDONLY))
3504 		if (ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block)))
3505 			goto failed_mount3;
3506 
3507 	/*
3508 	 * The first inode we look at is the journal inode.  Don't try
3509 	 * root first: it may be modified in the journal!
3510 	 */
3511 	if (!test_opt(sb, NOLOAD) &&
3512 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
3513 		if (ext4_load_journal(sb, es, journal_devnum))
3514 			goto failed_mount3;
3515 	} else if (test_opt(sb, NOLOAD) && !(sb->s_flags & MS_RDONLY) &&
3516 	      EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
3517 		ext4_msg(sb, KERN_ERR, "required journal recovery "
3518 		       "suppressed and not mounted read-only");
3519 		goto failed_mount_wq;
3520 	} else {
3521 		clear_opt(sb, DATA_FLAGS);
3522 		sbi->s_journal = NULL;
3523 		needs_recovery = 0;
3524 		goto no_journal;
3525 	}
3526 
3527 	if (ext4_blocks_count(es) > 0xffffffffULL &&
3528 	    !jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
3529 				       JBD2_FEATURE_INCOMPAT_64BIT)) {
3530 		ext4_msg(sb, KERN_ERR, "Failed to set 64-bit journal feature");
3531 		goto failed_mount_wq;
3532 	}
3533 
3534 	if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
3535 		jbd2_journal_set_features(sbi->s_journal,
3536 				JBD2_FEATURE_COMPAT_CHECKSUM, 0,
3537 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
3538 	} else if (test_opt(sb, JOURNAL_CHECKSUM)) {
3539 		jbd2_journal_set_features(sbi->s_journal,
3540 				JBD2_FEATURE_COMPAT_CHECKSUM, 0, 0);
3541 		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
3542 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
3543 	} else {
3544 		jbd2_journal_clear_features(sbi->s_journal,
3545 				JBD2_FEATURE_COMPAT_CHECKSUM, 0,
3546 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
3547 	}
3548 
3549 	/* We have now updated the journal if required, so we can
3550 	 * validate the data journaling mode. */
3551 	switch (test_opt(sb, DATA_FLAGS)) {
3552 	case 0:
3553 		/* No mode set, assume a default based on the journal
3554 		 * capabilities: ORDERED_DATA if the journal can
3555 		 * cope, else JOURNAL_DATA
3556 		 */
3557 		if (jbd2_journal_check_available_features
3558 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE))
3559 			set_opt(sb, ORDERED_DATA);
3560 		else
3561 			set_opt(sb, JOURNAL_DATA);
3562 		break;
3563 
3564 	case EXT4_MOUNT_ORDERED_DATA:
3565 	case EXT4_MOUNT_WRITEBACK_DATA:
3566 		if (!jbd2_journal_check_available_features
3567 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
3568 			ext4_msg(sb, KERN_ERR, "Journal does not support "
3569 			       "requested data journaling mode");
3570 			goto failed_mount_wq;
3571 		}
3572 	default:
3573 		break;
3574 	}
3575 	set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
3576 
3577 	/*
3578 	 * The journal may have updated the bg summary counts, so we
3579 	 * need to update the global counters.
3580 	 */
3581 	percpu_counter_set(&sbi->s_freeblocks_counter,
3582 			   ext4_count_free_blocks(sb));
3583 	percpu_counter_set(&sbi->s_freeinodes_counter,
3584 			   ext4_count_free_inodes(sb));
3585 	percpu_counter_set(&sbi->s_dirs_counter,
3586 			   ext4_count_dirs(sb));
3587 	percpu_counter_set(&sbi->s_dirtyblocks_counter, 0);
3588 
3589 no_journal:
3590 	/*
3591 	 * The maximum number of concurrent works can be high and
3592 	 * concurrency isn't really necessary.  Limit it to 1.
3593 	 */
3594 	EXT4_SB(sb)->dio_unwritten_wq =
3595 		alloc_workqueue("ext4-dio-unwritten", WQ_MEM_RECLAIM | WQ_UNBOUND, 1);
3596 	if (!EXT4_SB(sb)->dio_unwritten_wq) {
3597 		printk(KERN_ERR "EXT4-fs: failed to create DIO workqueue\n");
3598 		goto failed_mount_wq;
3599 	}
3600 
3601 	/*
3602 	 * The jbd2_journal_load will have done any necessary log recovery,
3603 	 * so we can safely mount the rest of the filesystem now.
3604 	 */
3605 
3606 	root = ext4_iget(sb, EXT4_ROOT_INO);
3607 	if (IS_ERR(root)) {
3608 		ext4_msg(sb, KERN_ERR, "get root inode failed");
3609 		ret = PTR_ERR(root);
3610 		root = NULL;
3611 		goto failed_mount4;
3612 	}
3613 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
3614 		ext4_msg(sb, KERN_ERR, "corrupt root inode, run e2fsck");
3615 		goto failed_mount4;
3616 	}
3617 	sb->s_root = d_alloc_root(root);
3618 	if (!sb->s_root) {
3619 		ext4_msg(sb, KERN_ERR, "get root dentry failed");
3620 		ret = -ENOMEM;
3621 		goto failed_mount4;
3622 	}
3623 
3624 	ext4_setup_super(sb, es, sb->s_flags & MS_RDONLY);
3625 
3626 	/* determine the minimum size of new large inodes, if present */
3627 	if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
3628 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
3629 						     EXT4_GOOD_OLD_INODE_SIZE;
3630 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3631 				       EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE)) {
3632 			if (sbi->s_want_extra_isize <
3633 			    le16_to_cpu(es->s_want_extra_isize))
3634 				sbi->s_want_extra_isize =
3635 					le16_to_cpu(es->s_want_extra_isize);
3636 			if (sbi->s_want_extra_isize <
3637 			    le16_to_cpu(es->s_min_extra_isize))
3638 				sbi->s_want_extra_isize =
3639 					le16_to_cpu(es->s_min_extra_isize);
3640 		}
3641 	}
3642 	/* Check if enough inode space is available */
3643 	if (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize >
3644 							sbi->s_inode_size) {
3645 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
3646 						       EXT4_GOOD_OLD_INODE_SIZE;
3647 		ext4_msg(sb, KERN_INFO, "required extra inode space not"
3648 			 "available");
3649 	}
3650 
3651 	if (test_opt(sb, DELALLOC) &&
3652 	    (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)) {
3653 		ext4_msg(sb, KERN_WARNING, "Ignoring delalloc option - "
3654 			 "requested data journaling mode");
3655 		clear_opt(sb, DELALLOC);
3656 	}
3657 	if (test_opt(sb, DIOREAD_NOLOCK)) {
3658 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
3659 			ext4_msg(sb, KERN_WARNING, "Ignoring dioread_nolock "
3660 				"option - requested data journaling mode");
3661 			clear_opt(sb, DIOREAD_NOLOCK);
3662 		}
3663 		if (sb->s_blocksize < PAGE_SIZE) {
3664 			ext4_msg(sb, KERN_WARNING, "Ignoring dioread_nolock "
3665 				"option - block size is too small");
3666 			clear_opt(sb, DIOREAD_NOLOCK);
3667 		}
3668 	}
3669 
3670 	err = ext4_setup_system_zone(sb);
3671 	if (err) {
3672 		ext4_msg(sb, KERN_ERR, "failed to initialize system "
3673 			 "zone (%d)", err);
3674 		goto failed_mount4;
3675 	}
3676 
3677 	ext4_ext_init(sb);
3678 	err = ext4_mb_init(sb, needs_recovery);
3679 	if (err) {
3680 		ext4_msg(sb, KERN_ERR, "failed to initialize mballoc (%d)",
3681 			 err);
3682 		goto failed_mount4;
3683 	}
3684 
3685 	err = ext4_register_li_request(sb, first_not_zeroed);
3686 	if (err)
3687 		goto failed_mount4;
3688 
3689 	sbi->s_kobj.kset = ext4_kset;
3690 	init_completion(&sbi->s_kobj_unregister);
3691 	err = kobject_init_and_add(&sbi->s_kobj, &ext4_ktype, NULL,
3692 				   "%s", sb->s_id);
3693 	if (err) {
3694 		ext4_mb_release(sb);
3695 		ext4_ext_release(sb);
3696 		goto failed_mount4;
3697 	};
3698 
3699 	EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
3700 	ext4_orphan_cleanup(sb, es);
3701 	EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
3702 	if (needs_recovery) {
3703 		ext4_msg(sb, KERN_INFO, "recovery complete");
3704 		ext4_mark_recovery_complete(sb, es);
3705 	}
3706 	if (EXT4_SB(sb)->s_journal) {
3707 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
3708 			descr = " journalled data mode";
3709 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
3710 			descr = " ordered data mode";
3711 		else
3712 			descr = " writeback data mode";
3713 	} else
3714 		descr = "out journal";
3715 
3716 	ext4_msg(sb, KERN_INFO, "mounted filesystem with%s. "
3717 		 "Opts: %s%s%s", descr, sbi->s_es->s_mount_opts,
3718 		 *sbi->s_es->s_mount_opts ? "; " : "", orig_data);
3719 
3720 	if (es->s_error_count)
3721 		mod_timer(&sbi->s_err_report, jiffies + 300*HZ); /* 5 minutes */
3722 
3723 	kfree(orig_data);
3724 	return 0;
3725 
3726 cantfind_ext4:
3727 	if (!silent)
3728 		ext4_msg(sb, KERN_ERR, "VFS: Can't find ext4 filesystem");
3729 	goto failed_mount;
3730 
3731 failed_mount4:
3732 	iput(root);
3733 	sb->s_root = NULL;
3734 	ext4_msg(sb, KERN_ERR, "mount failed");
3735 	destroy_workqueue(EXT4_SB(sb)->dio_unwritten_wq);
3736 failed_mount_wq:
3737 	ext4_release_system_zone(sb);
3738 	if (sbi->s_journal) {
3739 		jbd2_journal_destroy(sbi->s_journal);
3740 		sbi->s_journal = NULL;
3741 	}
3742 failed_mount3:
3743 	del_timer(&sbi->s_err_report);
3744 	if (sbi->s_flex_groups) {
3745 		if (is_vmalloc_addr(sbi->s_flex_groups))
3746 			vfree(sbi->s_flex_groups);
3747 		else
3748 			kfree(sbi->s_flex_groups);
3749 	}
3750 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
3751 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
3752 	percpu_counter_destroy(&sbi->s_dirs_counter);
3753 	percpu_counter_destroy(&sbi->s_dirtyblocks_counter);
3754 	if (sbi->s_mmp_tsk)
3755 		kthread_stop(sbi->s_mmp_tsk);
3756 failed_mount2:
3757 	for (i = 0; i < db_count; i++)
3758 		brelse(sbi->s_group_desc[i]);
3759 	kfree(sbi->s_group_desc);
3760 failed_mount:
3761 	if (sbi->s_proc) {
3762 		remove_proc_entry(sb->s_id, ext4_proc_root);
3763 	}
3764 #ifdef CONFIG_QUOTA
3765 	for (i = 0; i < MAXQUOTAS; i++)
3766 		kfree(sbi->s_qf_names[i]);
3767 #endif
3768 	ext4_blkdev_remove(sbi);
3769 	brelse(bh);
3770 out_fail:
3771 	sb->s_fs_info = NULL;
3772 	kfree(sbi->s_blockgroup_lock);
3773 	kfree(sbi);
3774 out_free_orig:
3775 	kfree(orig_data);
3776 	return ret;
3777 }
3778 
3779 /*
3780  * Setup any per-fs journal parameters now.  We'll do this both on
3781  * initial mount, once the journal has been initialised but before we've
3782  * done any recovery; and again on any subsequent remount.
3783  */
3784 static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
3785 {
3786 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3787 
3788 	journal->j_commit_interval = sbi->s_commit_interval;
3789 	journal->j_min_batch_time = sbi->s_min_batch_time;
3790 	journal->j_max_batch_time = sbi->s_max_batch_time;
3791 
3792 	write_lock(&journal->j_state_lock);
3793 	if (test_opt(sb, BARRIER))
3794 		journal->j_flags |= JBD2_BARRIER;
3795 	else
3796 		journal->j_flags &= ~JBD2_BARRIER;
3797 	if (test_opt(sb, DATA_ERR_ABORT))
3798 		journal->j_flags |= JBD2_ABORT_ON_SYNCDATA_ERR;
3799 	else
3800 		journal->j_flags &= ~JBD2_ABORT_ON_SYNCDATA_ERR;
3801 	write_unlock(&journal->j_state_lock);
3802 }
3803 
3804 static journal_t *ext4_get_journal(struct super_block *sb,
3805 				   unsigned int journal_inum)
3806 {
3807 	struct inode *journal_inode;
3808 	journal_t *journal;
3809 
3810 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
3811 
3812 	/* First, test for the existence of a valid inode on disk.  Bad
3813 	 * things happen if we iget() an unused inode, as the subsequent
3814 	 * iput() will try to delete it. */
3815 
3816 	journal_inode = ext4_iget(sb, journal_inum);
3817 	if (IS_ERR(journal_inode)) {
3818 		ext4_msg(sb, KERN_ERR, "no journal found");
3819 		return NULL;
3820 	}
3821 	if (!journal_inode->i_nlink) {
3822 		make_bad_inode(journal_inode);
3823 		iput(journal_inode);
3824 		ext4_msg(sb, KERN_ERR, "journal inode is deleted");
3825 		return NULL;
3826 	}
3827 
3828 	jbd_debug(2, "Journal inode found at %p: %lld bytes\n",
3829 		  journal_inode, journal_inode->i_size);
3830 	if (!S_ISREG(journal_inode->i_mode)) {
3831 		ext4_msg(sb, KERN_ERR, "invalid journal inode");
3832 		iput(journal_inode);
3833 		return NULL;
3834 	}
3835 
3836 	journal = jbd2_journal_init_inode(journal_inode);
3837 	if (!journal) {
3838 		ext4_msg(sb, KERN_ERR, "Could not load journal inode");
3839 		iput(journal_inode);
3840 		return NULL;
3841 	}
3842 	journal->j_private = sb;
3843 	ext4_init_journal_params(sb, journal);
3844 	return journal;
3845 }
3846 
3847 static journal_t *ext4_get_dev_journal(struct super_block *sb,
3848 				       dev_t j_dev)
3849 {
3850 	struct buffer_head *bh;
3851 	journal_t *journal;
3852 	ext4_fsblk_t start;
3853 	ext4_fsblk_t len;
3854 	int hblock, blocksize;
3855 	ext4_fsblk_t sb_block;
3856 	unsigned long offset;
3857 	struct ext4_super_block *es;
3858 	struct block_device *bdev;
3859 
3860 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
3861 
3862 	bdev = ext4_blkdev_get(j_dev, sb);
3863 	if (bdev == NULL)
3864 		return NULL;
3865 
3866 	blocksize = sb->s_blocksize;
3867 	hblock = bdev_logical_block_size(bdev);
3868 	if (blocksize < hblock) {
3869 		ext4_msg(sb, KERN_ERR,
3870 			"blocksize too small for journal device");
3871 		goto out_bdev;
3872 	}
3873 
3874 	sb_block = EXT4_MIN_BLOCK_SIZE / blocksize;
3875 	offset = EXT4_MIN_BLOCK_SIZE % blocksize;
3876 	set_blocksize(bdev, blocksize);
3877 	if (!(bh = __bread(bdev, sb_block, blocksize))) {
3878 		ext4_msg(sb, KERN_ERR, "couldn't read superblock of "
3879 		       "external journal");
3880 		goto out_bdev;
3881 	}
3882 
3883 	es = (struct ext4_super_block *) (((char *)bh->b_data) + offset);
3884 	if ((le16_to_cpu(es->s_magic) != EXT4_SUPER_MAGIC) ||
3885 	    !(le32_to_cpu(es->s_feature_incompat) &
3886 	      EXT4_FEATURE_INCOMPAT_JOURNAL_DEV)) {
3887 		ext4_msg(sb, KERN_ERR, "external journal has "
3888 					"bad superblock");
3889 		brelse(bh);
3890 		goto out_bdev;
3891 	}
3892 
3893 	if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
3894 		ext4_msg(sb, KERN_ERR, "journal UUID does not match");
3895 		brelse(bh);
3896 		goto out_bdev;
3897 	}
3898 
3899 	len = ext4_blocks_count(es);
3900 	start = sb_block + 1;
3901 	brelse(bh);	/* we're done with the superblock */
3902 
3903 	journal = jbd2_journal_init_dev(bdev, sb->s_bdev,
3904 					start, len, blocksize);
3905 	if (!journal) {
3906 		ext4_msg(sb, KERN_ERR, "failed to create device journal");
3907 		goto out_bdev;
3908 	}
3909 	journal->j_private = sb;
3910 	ll_rw_block(READ, 1, &journal->j_sb_buffer);
3911 	wait_on_buffer(journal->j_sb_buffer);
3912 	if (!buffer_uptodate(journal->j_sb_buffer)) {
3913 		ext4_msg(sb, KERN_ERR, "I/O error on journal device");
3914 		goto out_journal;
3915 	}
3916 	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
3917 		ext4_msg(sb, KERN_ERR, "External journal has more than one "
3918 					"user (unsupported) - %d",
3919 			be32_to_cpu(journal->j_superblock->s_nr_users));
3920 		goto out_journal;
3921 	}
3922 	EXT4_SB(sb)->journal_bdev = bdev;
3923 	ext4_init_journal_params(sb, journal);
3924 	return journal;
3925 
3926 out_journal:
3927 	jbd2_journal_destroy(journal);
3928 out_bdev:
3929 	ext4_blkdev_put(bdev);
3930 	return NULL;
3931 }
3932 
3933 static int ext4_load_journal(struct super_block *sb,
3934 			     struct ext4_super_block *es,
3935 			     unsigned long journal_devnum)
3936 {
3937 	journal_t *journal;
3938 	unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
3939 	dev_t journal_dev;
3940 	int err = 0;
3941 	int really_read_only;
3942 
3943 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
3944 
3945 	if (journal_devnum &&
3946 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
3947 		ext4_msg(sb, KERN_INFO, "external journal device major/minor "
3948 			"numbers have changed");
3949 		journal_dev = new_decode_dev(journal_devnum);
3950 	} else
3951 		journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));
3952 
3953 	really_read_only = bdev_read_only(sb->s_bdev);
3954 
3955 	/*
3956 	 * Are we loading a blank journal or performing recovery after a
3957 	 * crash?  For recovery, we need to check in advance whether we
3958 	 * can get read-write access to the device.
3959 	 */
3960 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
3961 		if (sb->s_flags & MS_RDONLY) {
3962 			ext4_msg(sb, KERN_INFO, "INFO: recovery "
3963 					"required on readonly filesystem");
3964 			if (really_read_only) {
3965 				ext4_msg(sb, KERN_ERR, "write access "
3966 					"unavailable, cannot proceed");
3967 				return -EROFS;
3968 			}
3969 			ext4_msg(sb, KERN_INFO, "write access will "
3970 			       "be enabled during recovery");
3971 		}
3972 	}
3973 
3974 	if (journal_inum && journal_dev) {
3975 		ext4_msg(sb, KERN_ERR, "filesystem has both journal "
3976 		       "and inode journals!");
3977 		return -EINVAL;
3978 	}
3979 
3980 	if (journal_inum) {
3981 		if (!(journal = ext4_get_journal(sb, journal_inum)))
3982 			return -EINVAL;
3983 	} else {
3984 		if (!(journal = ext4_get_dev_journal(sb, journal_dev)))
3985 			return -EINVAL;
3986 	}
3987 
3988 	if (!(journal->j_flags & JBD2_BARRIER))
3989 		ext4_msg(sb, KERN_INFO, "barriers disabled");
3990 
3991 	if (!really_read_only && test_opt(sb, UPDATE_JOURNAL)) {
3992 		err = jbd2_journal_update_format(journal);
3993 		if (err)  {
3994 			ext4_msg(sb, KERN_ERR, "error updating journal");
3995 			jbd2_journal_destroy(journal);
3996 			return err;
3997 		}
3998 	}
3999 
4000 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER))
4001 		err = jbd2_journal_wipe(journal, !really_read_only);
4002 	if (!err) {
4003 		char *save = kmalloc(EXT4_S_ERR_LEN, GFP_KERNEL);
4004 		if (save)
4005 			memcpy(save, ((char *) es) +
4006 			       EXT4_S_ERR_START, EXT4_S_ERR_LEN);
4007 		err = jbd2_journal_load(journal);
4008 		if (save)
4009 			memcpy(((char *) es) + EXT4_S_ERR_START,
4010 			       save, EXT4_S_ERR_LEN);
4011 		kfree(save);
4012 	}
4013 
4014 	if (err) {
4015 		ext4_msg(sb, KERN_ERR, "error loading journal");
4016 		jbd2_journal_destroy(journal);
4017 		return err;
4018 	}
4019 
4020 	EXT4_SB(sb)->s_journal = journal;
4021 	ext4_clear_journal_err(sb, es);
4022 
4023 	if (!really_read_only && journal_devnum &&
4024 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
4025 		es->s_journal_dev = cpu_to_le32(journal_devnum);
4026 
4027 		/* Make sure we flush the recovery flag to disk. */
4028 		ext4_commit_super(sb, 1);
4029 	}
4030 
4031 	return 0;
4032 }
4033 
4034 static int ext4_commit_super(struct super_block *sb, int sync)
4035 {
4036 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
4037 	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
4038 	int error = 0;
4039 
4040 	if (!sbh)
4041 		return error;
4042 	if (buffer_write_io_error(sbh)) {
4043 		/*
4044 		 * Oh, dear.  A previous attempt to write the
4045 		 * superblock failed.  This could happen because the
4046 		 * USB device was yanked out.  Or it could happen to
4047 		 * be a transient write error and maybe the block will
4048 		 * be remapped.  Nothing we can do but to retry the
4049 		 * write and hope for the best.
4050 		 */
4051 		ext4_msg(sb, KERN_ERR, "previous I/O error to "
4052 		       "superblock detected");
4053 		clear_buffer_write_io_error(sbh);
4054 		set_buffer_uptodate(sbh);
4055 	}
4056 	/*
4057 	 * If the file system is mounted read-only, don't update the
4058 	 * superblock write time.  This avoids updating the superblock
4059 	 * write time when we are mounting the root file system
4060 	 * read/only but we need to replay the journal; at that point,
4061 	 * for people who are east of GMT and who make their clock
4062 	 * tick in localtime for Windows bug-for-bug compatibility,
4063 	 * the clock is set in the future, and this will cause e2fsck
4064 	 * to complain and force a full file system check.
4065 	 */
4066 	if (!(sb->s_flags & MS_RDONLY))
4067 		es->s_wtime = cpu_to_le32(get_seconds());
4068 	if (sb->s_bdev->bd_part)
4069 		es->s_kbytes_written =
4070 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written +
4071 			    ((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
4072 			      EXT4_SB(sb)->s_sectors_written_start) >> 1));
4073 	else
4074 		es->s_kbytes_written =
4075 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written);
4076 	ext4_free_blocks_count_set(es, percpu_counter_sum_positive(
4077 					   &EXT4_SB(sb)->s_freeblocks_counter));
4078 	es->s_free_inodes_count =
4079 		cpu_to_le32(percpu_counter_sum_positive(
4080 				&EXT4_SB(sb)->s_freeinodes_counter));
4081 	sb->s_dirt = 0;
4082 	BUFFER_TRACE(sbh, "marking dirty");
4083 	mark_buffer_dirty(sbh);
4084 	if (sync) {
4085 		error = sync_dirty_buffer(sbh);
4086 		if (error)
4087 			return error;
4088 
4089 		error = buffer_write_io_error(sbh);
4090 		if (error) {
4091 			ext4_msg(sb, KERN_ERR, "I/O error while writing "
4092 			       "superblock");
4093 			clear_buffer_write_io_error(sbh);
4094 			set_buffer_uptodate(sbh);
4095 		}
4096 	}
4097 	return error;
4098 }
4099 
4100 /*
4101  * Have we just finished recovery?  If so, and if we are mounting (or
4102  * remounting) the filesystem readonly, then we will end up with a
4103  * consistent fs on disk.  Record that fact.
4104  */
4105 static void ext4_mark_recovery_complete(struct super_block *sb,
4106 					struct ext4_super_block *es)
4107 {
4108 	journal_t *journal = EXT4_SB(sb)->s_journal;
4109 
4110 	if (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
4111 		BUG_ON(journal != NULL);
4112 		return;
4113 	}
4114 	jbd2_journal_lock_updates(journal);
4115 	if (jbd2_journal_flush(journal) < 0)
4116 		goto out;
4117 
4118 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER) &&
4119 	    sb->s_flags & MS_RDONLY) {
4120 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4121 		ext4_commit_super(sb, 1);
4122 	}
4123 
4124 out:
4125 	jbd2_journal_unlock_updates(journal);
4126 }
4127 
4128 /*
4129  * If we are mounting (or read-write remounting) a filesystem whose journal
4130  * has recorded an error from a previous lifetime, move that error to the
4131  * main filesystem now.
4132  */
4133 static void ext4_clear_journal_err(struct super_block *sb,
4134 				   struct ext4_super_block *es)
4135 {
4136 	journal_t *journal;
4137 	int j_errno;
4138 	const char *errstr;
4139 
4140 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4141 
4142 	journal = EXT4_SB(sb)->s_journal;
4143 
4144 	/*
4145 	 * Now check for any error status which may have been recorded in the
4146 	 * journal by a prior ext4_error() or ext4_abort()
4147 	 */
4148 
4149 	j_errno = jbd2_journal_errno(journal);
4150 	if (j_errno) {
4151 		char nbuf[16];
4152 
4153 		errstr = ext4_decode_error(sb, j_errno, nbuf);
4154 		ext4_warning(sb, "Filesystem error recorded "
4155 			     "from previous mount: %s", errstr);
4156 		ext4_warning(sb, "Marking fs in need of filesystem check.");
4157 
4158 		EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
4159 		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
4160 		ext4_commit_super(sb, 1);
4161 
4162 		jbd2_journal_clear_err(journal);
4163 	}
4164 }
4165 
4166 /*
4167  * Force the running and committing transactions to commit,
4168  * and wait on the commit.
4169  */
4170 int ext4_force_commit(struct super_block *sb)
4171 {
4172 	journal_t *journal;
4173 	int ret = 0;
4174 
4175 	if (sb->s_flags & MS_RDONLY)
4176 		return 0;
4177 
4178 	journal = EXT4_SB(sb)->s_journal;
4179 	if (journal) {
4180 		vfs_check_frozen(sb, SB_FREEZE_TRANS);
4181 		ret = ext4_journal_force_commit(journal);
4182 	}
4183 
4184 	return ret;
4185 }
4186 
4187 static void ext4_write_super(struct super_block *sb)
4188 {
4189 	lock_super(sb);
4190 	ext4_commit_super(sb, 1);
4191 	unlock_super(sb);
4192 }
4193 
4194 static int ext4_sync_fs(struct super_block *sb, int wait)
4195 {
4196 	int ret = 0;
4197 	tid_t target;
4198 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4199 
4200 	trace_ext4_sync_fs(sb, wait);
4201 	flush_workqueue(sbi->dio_unwritten_wq);
4202 	if (jbd2_journal_start_commit(sbi->s_journal, &target)) {
4203 		if (wait)
4204 			jbd2_log_wait_commit(sbi->s_journal, target);
4205 	}
4206 	return ret;
4207 }
4208 
4209 /*
4210  * LVM calls this function before a (read-only) snapshot is created.  This
4211  * gives us a chance to flush the journal completely and mark the fs clean.
4212  *
4213  * Note that only this function cannot bring a filesystem to be in a clean
4214  * state independently, because ext4 prevents a new handle from being started
4215  * by @sb->s_frozen, which stays in an upper layer.  It thus needs help from
4216  * the upper layer.
4217  */
4218 static int ext4_freeze(struct super_block *sb)
4219 {
4220 	int error = 0;
4221 	journal_t *journal;
4222 
4223 	if (sb->s_flags & MS_RDONLY)
4224 		return 0;
4225 
4226 	journal = EXT4_SB(sb)->s_journal;
4227 
4228 	/* Now we set up the journal barrier. */
4229 	jbd2_journal_lock_updates(journal);
4230 
4231 	/*
4232 	 * Don't clear the needs_recovery flag if we failed to flush
4233 	 * the journal.
4234 	 */
4235 	error = jbd2_journal_flush(journal);
4236 	if (error < 0)
4237 		goto out;
4238 
4239 	/* Journal blocked and flushed, clear needs_recovery flag. */
4240 	EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4241 	error = ext4_commit_super(sb, 1);
4242 out:
4243 	/* we rely on s_frozen to stop further updates */
4244 	jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
4245 	return error;
4246 }
4247 
4248 /*
4249  * Called by LVM after the snapshot is done.  We need to reset the RECOVER
4250  * flag here, even though the filesystem is not technically dirty yet.
4251  */
4252 static int ext4_unfreeze(struct super_block *sb)
4253 {
4254 	if (sb->s_flags & MS_RDONLY)
4255 		return 0;
4256 
4257 	lock_super(sb);
4258 	/* Reset the needs_recovery flag before the fs is unlocked. */
4259 	EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4260 	ext4_commit_super(sb, 1);
4261 	unlock_super(sb);
4262 	return 0;
4263 }
4264 
4265 /*
4266  * Structure to save mount options for ext4_remount's benefit
4267  */
4268 struct ext4_mount_options {
4269 	unsigned long s_mount_opt;
4270 	unsigned long s_mount_opt2;
4271 	uid_t s_resuid;
4272 	gid_t s_resgid;
4273 	unsigned long s_commit_interval;
4274 	u32 s_min_batch_time, s_max_batch_time;
4275 #ifdef CONFIG_QUOTA
4276 	int s_jquota_fmt;
4277 	char *s_qf_names[MAXQUOTAS];
4278 #endif
4279 };
4280 
4281 static int ext4_remount(struct super_block *sb, int *flags, char *data)
4282 {
4283 	struct ext4_super_block *es;
4284 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4285 	ext4_fsblk_t n_blocks_count = 0;
4286 	unsigned long old_sb_flags;
4287 	struct ext4_mount_options old_opts;
4288 	int enable_quota = 0;
4289 	ext4_group_t g;
4290 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
4291 	int err = 0;
4292 #ifdef CONFIG_QUOTA
4293 	int i;
4294 #endif
4295 	char *orig_data = kstrdup(data, GFP_KERNEL);
4296 
4297 	/* Store the original options */
4298 	lock_super(sb);
4299 	old_sb_flags = sb->s_flags;
4300 	old_opts.s_mount_opt = sbi->s_mount_opt;
4301 	old_opts.s_mount_opt2 = sbi->s_mount_opt2;
4302 	old_opts.s_resuid = sbi->s_resuid;
4303 	old_opts.s_resgid = sbi->s_resgid;
4304 	old_opts.s_commit_interval = sbi->s_commit_interval;
4305 	old_opts.s_min_batch_time = sbi->s_min_batch_time;
4306 	old_opts.s_max_batch_time = sbi->s_max_batch_time;
4307 #ifdef CONFIG_QUOTA
4308 	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
4309 	for (i = 0; i < MAXQUOTAS; i++)
4310 		old_opts.s_qf_names[i] = sbi->s_qf_names[i];
4311 #endif
4312 	if (sbi->s_journal && sbi->s_journal->j_task->io_context)
4313 		journal_ioprio = sbi->s_journal->j_task->io_context->ioprio;
4314 
4315 	/*
4316 	 * Allow the "check" option to be passed as a remount option.
4317 	 */
4318 	if (!parse_options(data, sb, NULL, &journal_ioprio,
4319 			   &n_blocks_count, 1)) {
4320 		err = -EINVAL;
4321 		goto restore_opts;
4322 	}
4323 
4324 	if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
4325 		ext4_abort(sb, "Abort forced by user");
4326 
4327 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
4328 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
4329 
4330 	es = sbi->s_es;
4331 
4332 	if (sbi->s_journal) {
4333 		ext4_init_journal_params(sb, sbi->s_journal);
4334 		set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
4335 	}
4336 
4337 	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY) ||
4338 		n_blocks_count > ext4_blocks_count(es)) {
4339 		if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) {
4340 			err = -EROFS;
4341 			goto restore_opts;
4342 		}
4343 
4344 		if (*flags & MS_RDONLY) {
4345 			err = dquot_suspend(sb, -1);
4346 			if (err < 0)
4347 				goto restore_opts;
4348 
4349 			/*
4350 			 * First of all, the unconditional stuff we have to do
4351 			 * to disable replay of the journal when we next remount
4352 			 */
4353 			sb->s_flags |= MS_RDONLY;
4354 
4355 			/*
4356 			 * OK, test if we are remounting a valid rw partition
4357 			 * readonly, and if so set the rdonly flag and then
4358 			 * mark the partition as valid again.
4359 			 */
4360 			if (!(es->s_state & cpu_to_le16(EXT4_VALID_FS)) &&
4361 			    (sbi->s_mount_state & EXT4_VALID_FS))
4362 				es->s_state = cpu_to_le16(sbi->s_mount_state);
4363 
4364 			if (sbi->s_journal)
4365 				ext4_mark_recovery_complete(sb, es);
4366 		} else {
4367 			/* Make sure we can mount this feature set readwrite */
4368 			if (!ext4_feature_set_ok(sb, 0)) {
4369 				err = -EROFS;
4370 				goto restore_opts;
4371 			}
4372 			/*
4373 			 * Make sure the group descriptor checksums
4374 			 * are sane.  If they aren't, refuse to remount r/w.
4375 			 */
4376 			for (g = 0; g < sbi->s_groups_count; g++) {
4377 				struct ext4_group_desc *gdp =
4378 					ext4_get_group_desc(sb, g, NULL);
4379 
4380 				if (!ext4_group_desc_csum_verify(sbi, g, gdp)) {
4381 					ext4_msg(sb, KERN_ERR,
4382 	       "ext4_remount: Checksum for group %u failed (%u!=%u)",
4383 		g, le16_to_cpu(ext4_group_desc_csum(sbi, g, gdp)),
4384 					       le16_to_cpu(gdp->bg_checksum));
4385 					err = -EINVAL;
4386 					goto restore_opts;
4387 				}
4388 			}
4389 
4390 			/*
4391 			 * If we have an unprocessed orphan list hanging
4392 			 * around from a previously readonly bdev mount,
4393 			 * require a full umount/remount for now.
4394 			 */
4395 			if (es->s_last_orphan) {
4396 				ext4_msg(sb, KERN_WARNING, "Couldn't "
4397 				       "remount RDWR because of unprocessed "
4398 				       "orphan inode list.  Please "
4399 				       "umount/remount instead");
4400 				err = -EINVAL;
4401 				goto restore_opts;
4402 			}
4403 
4404 			/*
4405 			 * Mounting a RDONLY partition read-write, so reread
4406 			 * and store the current valid flag.  (It may have
4407 			 * been changed by e2fsck since we originally mounted
4408 			 * the partition.)
4409 			 */
4410 			if (sbi->s_journal)
4411 				ext4_clear_journal_err(sb, es);
4412 			sbi->s_mount_state = le16_to_cpu(es->s_state);
4413 			if ((err = ext4_group_extend(sb, es, n_blocks_count)))
4414 				goto restore_opts;
4415 			if (!ext4_setup_super(sb, es, 0))
4416 				sb->s_flags &= ~MS_RDONLY;
4417 			if (EXT4_HAS_INCOMPAT_FEATURE(sb,
4418 						     EXT4_FEATURE_INCOMPAT_MMP))
4419 				if (ext4_multi_mount_protect(sb,
4420 						le64_to_cpu(es->s_mmp_block))) {
4421 					err = -EROFS;
4422 					goto restore_opts;
4423 				}
4424 			enable_quota = 1;
4425 		}
4426 	}
4427 
4428 	/*
4429 	 * Reinitialize lazy itable initialization thread based on
4430 	 * current settings
4431 	 */
4432 	if ((sb->s_flags & MS_RDONLY) || !test_opt(sb, INIT_INODE_TABLE))
4433 		ext4_unregister_li_request(sb);
4434 	else {
4435 		ext4_group_t first_not_zeroed;
4436 		first_not_zeroed = ext4_has_uninit_itable(sb);
4437 		ext4_register_li_request(sb, first_not_zeroed);
4438 	}
4439 
4440 	ext4_setup_system_zone(sb);
4441 	if (sbi->s_journal == NULL)
4442 		ext4_commit_super(sb, 1);
4443 
4444 #ifdef CONFIG_QUOTA
4445 	/* Release old quota file names */
4446 	for (i = 0; i < MAXQUOTAS; i++)
4447 		if (old_opts.s_qf_names[i] &&
4448 		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
4449 			kfree(old_opts.s_qf_names[i]);
4450 #endif
4451 	unlock_super(sb);
4452 	if (enable_quota)
4453 		dquot_resume(sb, -1);
4454 
4455 	ext4_msg(sb, KERN_INFO, "re-mounted. Opts: %s", orig_data);
4456 	kfree(orig_data);
4457 	return 0;
4458 
4459 restore_opts:
4460 	sb->s_flags = old_sb_flags;
4461 	sbi->s_mount_opt = old_opts.s_mount_opt;
4462 	sbi->s_mount_opt2 = old_opts.s_mount_opt2;
4463 	sbi->s_resuid = old_opts.s_resuid;
4464 	sbi->s_resgid = old_opts.s_resgid;
4465 	sbi->s_commit_interval = old_opts.s_commit_interval;
4466 	sbi->s_min_batch_time = old_opts.s_min_batch_time;
4467 	sbi->s_max_batch_time = old_opts.s_max_batch_time;
4468 #ifdef CONFIG_QUOTA
4469 	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
4470 	for (i = 0; i < MAXQUOTAS; i++) {
4471 		if (sbi->s_qf_names[i] &&
4472 		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
4473 			kfree(sbi->s_qf_names[i]);
4474 		sbi->s_qf_names[i] = old_opts.s_qf_names[i];
4475 	}
4476 #endif
4477 	unlock_super(sb);
4478 	kfree(orig_data);
4479 	return err;
4480 }
4481 
4482 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
4483 {
4484 	struct super_block *sb = dentry->d_sb;
4485 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4486 	struct ext4_super_block *es = sbi->s_es;
4487 	u64 fsid;
4488 	s64 bfree;
4489 
4490 	if (test_opt(sb, MINIX_DF)) {
4491 		sbi->s_overhead_last = 0;
4492 	} else if (sbi->s_blocks_last != ext4_blocks_count(es)) {
4493 		ext4_group_t i, ngroups = ext4_get_groups_count(sb);
4494 		ext4_fsblk_t overhead = 0;
4495 
4496 		/*
4497 		 * Compute the overhead (FS structures).  This is constant
4498 		 * for a given filesystem unless the number of block groups
4499 		 * changes so we cache the previous value until it does.
4500 		 */
4501 
4502 		/*
4503 		 * All of the blocks before first_data_block are
4504 		 * overhead
4505 		 */
4506 		overhead = le32_to_cpu(es->s_first_data_block);
4507 
4508 		/*
4509 		 * Add the overhead attributed to the superblock and
4510 		 * block group descriptors.  If the sparse superblocks
4511 		 * feature is turned on, then not all groups have this.
4512 		 */
4513 		for (i = 0; i < ngroups; i++) {
4514 			overhead += ext4_bg_has_super(sb, i) +
4515 				ext4_bg_num_gdb(sb, i);
4516 			cond_resched();
4517 		}
4518 
4519 		/*
4520 		 * Every block group has an inode bitmap, a block
4521 		 * bitmap, and an inode table.
4522 		 */
4523 		overhead += ngroups * (2 + sbi->s_itb_per_group);
4524 		sbi->s_overhead_last = overhead;
4525 		smp_wmb();
4526 		sbi->s_blocks_last = ext4_blocks_count(es);
4527 	}
4528 
4529 	buf->f_type = EXT4_SUPER_MAGIC;
4530 	buf->f_bsize = sb->s_blocksize;
4531 	buf->f_blocks = ext4_blocks_count(es) - sbi->s_overhead_last;
4532 	bfree = percpu_counter_sum_positive(&sbi->s_freeblocks_counter) -
4533 		       percpu_counter_sum_positive(&sbi->s_dirtyblocks_counter);
4534 	/* prevent underflow in case that few free space is available */
4535 	buf->f_bfree = max_t(s64, bfree, 0);
4536 	buf->f_bavail = buf->f_bfree - ext4_r_blocks_count(es);
4537 	if (buf->f_bfree < ext4_r_blocks_count(es))
4538 		buf->f_bavail = 0;
4539 	buf->f_files = le32_to_cpu(es->s_inodes_count);
4540 	buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter);
4541 	buf->f_namelen = EXT4_NAME_LEN;
4542 	fsid = le64_to_cpup((void *)es->s_uuid) ^
4543 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
4544 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
4545 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
4546 
4547 	return 0;
4548 }
4549 
4550 /* Helper function for writing quotas on sync - we need to start transaction
4551  * before quota file is locked for write. Otherwise the are possible deadlocks:
4552  * Process 1                         Process 2
4553  * ext4_create()                     quota_sync()
4554  *   jbd2_journal_start()                  write_dquot()
4555  *   dquot_initialize()                         down(dqio_mutex)
4556  *     down(dqio_mutex)                    jbd2_journal_start()
4557  *
4558  */
4559 
4560 #ifdef CONFIG_QUOTA
4561 
4562 static inline struct inode *dquot_to_inode(struct dquot *dquot)
4563 {
4564 	return sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
4565 }
4566 
4567 static int ext4_write_dquot(struct dquot *dquot)
4568 {
4569 	int ret, err;
4570 	handle_t *handle;
4571 	struct inode *inode;
4572 
4573 	inode = dquot_to_inode(dquot);
4574 	handle = ext4_journal_start(inode,
4575 				    EXT4_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
4576 	if (IS_ERR(handle))
4577 		return PTR_ERR(handle);
4578 	ret = dquot_commit(dquot);
4579 	err = ext4_journal_stop(handle);
4580 	if (!ret)
4581 		ret = err;
4582 	return ret;
4583 }
4584 
4585 static int ext4_acquire_dquot(struct dquot *dquot)
4586 {
4587 	int ret, err;
4588 	handle_t *handle;
4589 
4590 	handle = ext4_journal_start(dquot_to_inode(dquot),
4591 				    EXT4_QUOTA_INIT_BLOCKS(dquot->dq_sb));
4592 	if (IS_ERR(handle))
4593 		return PTR_ERR(handle);
4594 	ret = dquot_acquire(dquot);
4595 	err = ext4_journal_stop(handle);
4596 	if (!ret)
4597 		ret = err;
4598 	return ret;
4599 }
4600 
4601 static int ext4_release_dquot(struct dquot *dquot)
4602 {
4603 	int ret, err;
4604 	handle_t *handle;
4605 
4606 	handle = ext4_journal_start(dquot_to_inode(dquot),
4607 				    EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
4608 	if (IS_ERR(handle)) {
4609 		/* Release dquot anyway to avoid endless cycle in dqput() */
4610 		dquot_release(dquot);
4611 		return PTR_ERR(handle);
4612 	}
4613 	ret = dquot_release(dquot);
4614 	err = ext4_journal_stop(handle);
4615 	if (!ret)
4616 		ret = err;
4617 	return ret;
4618 }
4619 
4620 static int ext4_mark_dquot_dirty(struct dquot *dquot)
4621 {
4622 	/* Are we journaling quotas? */
4623 	if (EXT4_SB(dquot->dq_sb)->s_qf_names[USRQUOTA] ||
4624 	    EXT4_SB(dquot->dq_sb)->s_qf_names[GRPQUOTA]) {
4625 		dquot_mark_dquot_dirty(dquot);
4626 		return ext4_write_dquot(dquot);
4627 	} else {
4628 		return dquot_mark_dquot_dirty(dquot);
4629 	}
4630 }
4631 
4632 static int ext4_write_info(struct super_block *sb, int type)
4633 {
4634 	int ret, err;
4635 	handle_t *handle;
4636 
4637 	/* Data block + inode block */
4638 	handle = ext4_journal_start(sb->s_root->d_inode, 2);
4639 	if (IS_ERR(handle))
4640 		return PTR_ERR(handle);
4641 	ret = dquot_commit_info(sb, type);
4642 	err = ext4_journal_stop(handle);
4643 	if (!ret)
4644 		ret = err;
4645 	return ret;
4646 }
4647 
4648 /*
4649  * Turn on quotas during mount time - we need to find
4650  * the quota file and such...
4651  */
4652 static int ext4_quota_on_mount(struct super_block *sb, int type)
4653 {
4654 	return dquot_quota_on_mount(sb, EXT4_SB(sb)->s_qf_names[type],
4655 					EXT4_SB(sb)->s_jquota_fmt, type);
4656 }
4657 
4658 /*
4659  * Standard function to be called on quota_on
4660  */
4661 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
4662 			 struct path *path)
4663 {
4664 	int err;
4665 
4666 	if (!test_opt(sb, QUOTA))
4667 		return -EINVAL;
4668 
4669 	/* Quotafile not on the same filesystem? */
4670 	if (path->mnt->mnt_sb != sb)
4671 		return -EXDEV;
4672 	/* Journaling quota? */
4673 	if (EXT4_SB(sb)->s_qf_names[type]) {
4674 		/* Quotafile not in fs root? */
4675 		if (path->dentry->d_parent != sb->s_root)
4676 			ext4_msg(sb, KERN_WARNING,
4677 				"Quota file not on filesystem root. "
4678 				"Journaled quota will not work");
4679 	}
4680 
4681 	/*
4682 	 * When we journal data on quota file, we have to flush journal to see
4683 	 * all updates to the file when we bypass pagecache...
4684 	 */
4685 	if (EXT4_SB(sb)->s_journal &&
4686 	    ext4_should_journal_data(path->dentry->d_inode)) {
4687 		/*
4688 		 * We don't need to lock updates but journal_flush() could
4689 		 * otherwise be livelocked...
4690 		 */
4691 		jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
4692 		err = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
4693 		jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
4694 		if (err)
4695 			return err;
4696 	}
4697 
4698 	return dquot_quota_on(sb, type, format_id, path);
4699 }
4700 
4701 static int ext4_quota_off(struct super_block *sb, int type)
4702 {
4703 	struct inode *inode = sb_dqopt(sb)->files[type];
4704 	handle_t *handle;
4705 
4706 	/* Force all delayed allocation blocks to be allocated.
4707 	 * Caller already holds s_umount sem */
4708 	if (test_opt(sb, DELALLOC))
4709 		sync_filesystem(sb);
4710 
4711 	if (!inode)
4712 		goto out;
4713 
4714 	/* Update modification times of quota files when userspace can
4715 	 * start looking at them */
4716 	handle = ext4_journal_start(inode, 1);
4717 	if (IS_ERR(handle))
4718 		goto out;
4719 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
4720 	ext4_mark_inode_dirty(handle, inode);
4721 	ext4_journal_stop(handle);
4722 
4723 out:
4724 	return dquot_quota_off(sb, type);
4725 }
4726 
4727 /* Read data from quotafile - avoid pagecache and such because we cannot afford
4728  * acquiring the locks... As quota files are never truncated and quota code
4729  * itself serializes the operations (and no one else should touch the files)
4730  * we don't have to be afraid of races */
4731 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
4732 			       size_t len, loff_t off)
4733 {
4734 	struct inode *inode = sb_dqopt(sb)->files[type];
4735 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
4736 	int err = 0;
4737 	int offset = off & (sb->s_blocksize - 1);
4738 	int tocopy;
4739 	size_t toread;
4740 	struct buffer_head *bh;
4741 	loff_t i_size = i_size_read(inode);
4742 
4743 	if (off > i_size)
4744 		return 0;
4745 	if (off+len > i_size)
4746 		len = i_size-off;
4747 	toread = len;
4748 	while (toread > 0) {
4749 		tocopy = sb->s_blocksize - offset < toread ?
4750 				sb->s_blocksize - offset : toread;
4751 		bh = ext4_bread(NULL, inode, blk, 0, &err);
4752 		if (err)
4753 			return err;
4754 		if (!bh)	/* A hole? */
4755 			memset(data, 0, tocopy);
4756 		else
4757 			memcpy(data, bh->b_data+offset, tocopy);
4758 		brelse(bh);
4759 		offset = 0;
4760 		toread -= tocopy;
4761 		data += tocopy;
4762 		blk++;
4763 	}
4764 	return len;
4765 }
4766 
4767 /* Write to quotafile (we know the transaction is already started and has
4768  * enough credits) */
4769 static ssize_t ext4_quota_write(struct super_block *sb, int type,
4770 				const char *data, size_t len, loff_t off)
4771 {
4772 	struct inode *inode = sb_dqopt(sb)->files[type];
4773 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
4774 	int err = 0;
4775 	int offset = off & (sb->s_blocksize - 1);
4776 	struct buffer_head *bh;
4777 	handle_t *handle = journal_current_handle();
4778 
4779 	if (EXT4_SB(sb)->s_journal && !handle) {
4780 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
4781 			" cancelled because transaction is not started",
4782 			(unsigned long long)off, (unsigned long long)len);
4783 		return -EIO;
4784 	}
4785 	/*
4786 	 * Since we account only one data block in transaction credits,
4787 	 * then it is impossible to cross a block boundary.
4788 	 */
4789 	if (sb->s_blocksize - offset < len) {
4790 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
4791 			" cancelled because not block aligned",
4792 			(unsigned long long)off, (unsigned long long)len);
4793 		return -EIO;
4794 	}
4795 
4796 	mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
4797 	bh = ext4_bread(handle, inode, blk, 1, &err);
4798 	if (!bh)
4799 		goto out;
4800 	err = ext4_journal_get_write_access(handle, bh);
4801 	if (err) {
4802 		brelse(bh);
4803 		goto out;
4804 	}
4805 	lock_buffer(bh);
4806 	memcpy(bh->b_data+offset, data, len);
4807 	flush_dcache_page(bh->b_page);
4808 	unlock_buffer(bh);
4809 	err = ext4_handle_dirty_metadata(handle, NULL, bh);
4810 	brelse(bh);
4811 out:
4812 	if (err) {
4813 		mutex_unlock(&inode->i_mutex);
4814 		return err;
4815 	}
4816 	if (inode->i_size < off + len) {
4817 		i_size_write(inode, off + len);
4818 		EXT4_I(inode)->i_disksize = inode->i_size;
4819 		ext4_mark_inode_dirty(handle, inode);
4820 	}
4821 	mutex_unlock(&inode->i_mutex);
4822 	return len;
4823 }
4824 
4825 #endif
4826 
4827 static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
4828 		       const char *dev_name, void *data)
4829 {
4830 	return mount_bdev(fs_type, flags, dev_name, data, ext4_fill_super);
4831 }
4832 
4833 #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
4834 static inline void register_as_ext2(void)
4835 {
4836 	int err = register_filesystem(&ext2_fs_type);
4837 	if (err)
4838 		printk(KERN_WARNING
4839 		       "EXT4-fs: Unable to register as ext2 (%d)\n", err);
4840 }
4841 
4842 static inline void unregister_as_ext2(void)
4843 {
4844 	unregister_filesystem(&ext2_fs_type);
4845 }
4846 
4847 static inline int ext2_feature_set_ok(struct super_block *sb)
4848 {
4849 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP))
4850 		return 0;
4851 	if (sb->s_flags & MS_RDONLY)
4852 		return 1;
4853 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))
4854 		return 0;
4855 	return 1;
4856 }
4857 MODULE_ALIAS("ext2");
4858 #else
4859 static inline void register_as_ext2(void) { }
4860 static inline void unregister_as_ext2(void) { }
4861 static inline int ext2_feature_set_ok(struct super_block *sb) { return 0; }
4862 #endif
4863 
4864 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
4865 static inline void register_as_ext3(void)
4866 {
4867 	int err = register_filesystem(&ext3_fs_type);
4868 	if (err)
4869 		printk(KERN_WARNING
4870 		       "EXT4-fs: Unable to register as ext3 (%d)\n", err);
4871 }
4872 
4873 static inline void unregister_as_ext3(void)
4874 {
4875 	unregister_filesystem(&ext3_fs_type);
4876 }
4877 
4878 static inline int ext3_feature_set_ok(struct super_block *sb)
4879 {
4880 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT3_FEATURE_INCOMPAT_SUPP))
4881 		return 0;
4882 	if (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL))
4883 		return 0;
4884 	if (sb->s_flags & MS_RDONLY)
4885 		return 1;
4886 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT3_FEATURE_RO_COMPAT_SUPP))
4887 		return 0;
4888 	return 1;
4889 }
4890 MODULE_ALIAS("ext3");
4891 #else
4892 static inline void register_as_ext3(void) { }
4893 static inline void unregister_as_ext3(void) { }
4894 static inline int ext3_feature_set_ok(struct super_block *sb) { return 0; }
4895 #endif
4896 
4897 static struct file_system_type ext4_fs_type = {
4898 	.owner		= THIS_MODULE,
4899 	.name		= "ext4",
4900 	.mount		= ext4_mount,
4901 	.kill_sb	= kill_block_super,
4902 	.fs_flags	= FS_REQUIRES_DEV,
4903 };
4904 
4905 static int __init ext4_init_feat_adverts(void)
4906 {
4907 	struct ext4_features *ef;
4908 	int ret = -ENOMEM;
4909 
4910 	ef = kzalloc(sizeof(struct ext4_features), GFP_KERNEL);
4911 	if (!ef)
4912 		goto out;
4913 
4914 	ef->f_kobj.kset = ext4_kset;
4915 	init_completion(&ef->f_kobj_unregister);
4916 	ret = kobject_init_and_add(&ef->f_kobj, &ext4_feat_ktype, NULL,
4917 				   "features");
4918 	if (ret) {
4919 		kfree(ef);
4920 		goto out;
4921 	}
4922 
4923 	ext4_feat = ef;
4924 	ret = 0;
4925 out:
4926 	return ret;
4927 }
4928 
4929 static void ext4_exit_feat_adverts(void)
4930 {
4931 	kobject_put(&ext4_feat->f_kobj);
4932 	wait_for_completion(&ext4_feat->f_kobj_unregister);
4933 	kfree(ext4_feat);
4934 }
4935 
4936 /* Shared across all ext4 file systems */
4937 wait_queue_head_t ext4__ioend_wq[EXT4_WQ_HASH_SZ];
4938 struct mutex ext4__aio_mutex[EXT4_WQ_HASH_SZ];
4939 
4940 static int __init ext4_init_fs(void)
4941 {
4942 	int i, err;
4943 
4944 	ext4_check_flag_values();
4945 
4946 	for (i = 0; i < EXT4_WQ_HASH_SZ; i++) {
4947 		mutex_init(&ext4__aio_mutex[i]);
4948 		init_waitqueue_head(&ext4__ioend_wq[i]);
4949 	}
4950 
4951 	err = ext4_init_pageio();
4952 	if (err)
4953 		return err;
4954 	err = ext4_init_system_zone();
4955 	if (err)
4956 		goto out7;
4957 	ext4_kset = kset_create_and_add("ext4", NULL, fs_kobj);
4958 	if (!ext4_kset)
4959 		goto out6;
4960 	ext4_proc_root = proc_mkdir("fs/ext4", NULL);
4961 	if (!ext4_proc_root)
4962 		goto out5;
4963 
4964 	err = ext4_init_feat_adverts();
4965 	if (err)
4966 		goto out4;
4967 
4968 	err = ext4_init_mballoc();
4969 	if (err)
4970 		goto out3;
4971 
4972 	err = ext4_init_xattr();
4973 	if (err)
4974 		goto out2;
4975 	err = init_inodecache();
4976 	if (err)
4977 		goto out1;
4978 	register_as_ext3();
4979 	register_as_ext2();
4980 	err = register_filesystem(&ext4_fs_type);
4981 	if (err)
4982 		goto out;
4983 
4984 	ext4_li_info = NULL;
4985 	mutex_init(&ext4_li_mtx);
4986 	return 0;
4987 out:
4988 	unregister_as_ext2();
4989 	unregister_as_ext3();
4990 	destroy_inodecache();
4991 out1:
4992 	ext4_exit_xattr();
4993 out2:
4994 	ext4_exit_mballoc();
4995 out3:
4996 	ext4_exit_feat_adverts();
4997 out4:
4998 	remove_proc_entry("fs/ext4", NULL);
4999 out5:
5000 	kset_unregister(ext4_kset);
5001 out6:
5002 	ext4_exit_system_zone();
5003 out7:
5004 	ext4_exit_pageio();
5005 	return err;
5006 }
5007 
5008 static void __exit ext4_exit_fs(void)
5009 {
5010 	ext4_destroy_lazyinit_thread();
5011 	unregister_as_ext2();
5012 	unregister_as_ext3();
5013 	unregister_filesystem(&ext4_fs_type);
5014 	destroy_inodecache();
5015 	ext4_exit_xattr();
5016 	ext4_exit_mballoc();
5017 	ext4_exit_feat_adverts();
5018 	remove_proc_entry("fs/ext4", NULL);
5019 	kset_unregister(ext4_kset);
5020 	ext4_exit_system_zone();
5021 	ext4_exit_pageio();
5022 }
5023 
5024 MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
5025 MODULE_DESCRIPTION("Fourth Extended Filesystem");
5026 MODULE_LICENSE("GPL");
5027 module_init(ext4_init_fs)
5028 module_exit(ext4_exit_fs)
5029