xref: /linux/fs/ext4/super.c (revision 092e0e7e520a1fca03e13c9f2d157432a8657ff2)
1 /*
2  *  linux/fs/ext4/super.c
3  *
4  * Copyright (C) 1992, 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  *
9  *  from
10  *
11  *  linux/fs/minix/inode.c
12  *
13  *  Copyright (C) 1991, 1992  Linus Torvalds
14  *
15  *  Big-endian to little-endian byte-swapping/bitmaps by
16  *        David S. Miller (davem@caip.rutgers.edu), 1995
17  */
18 
19 #include <linux/module.h>
20 #include <linux/string.h>
21 #include <linux/fs.h>
22 #include <linux/time.h>
23 #include <linux/vmalloc.h>
24 #include <linux/jbd2.h>
25 #include <linux/slab.h>
26 #include <linux/init.h>
27 #include <linux/blkdev.h>
28 #include <linux/parser.h>
29 #include <linux/buffer_head.h>
30 #include <linux/exportfs.h>
31 #include <linux/vfs.h>
32 #include <linux/random.h>
33 #include <linux/mount.h>
34 #include <linux/namei.h>
35 #include <linux/quotaops.h>
36 #include <linux/seq_file.h>
37 #include <linux/proc_fs.h>
38 #include <linux/ctype.h>
39 #include <linux/log2.h>
40 #include <linux/crc16.h>
41 #include <asm/uaccess.h>
42 
43 #include "ext4.h"
44 #include "ext4_jbd2.h"
45 #include "xattr.h"
46 #include "acl.h"
47 #include "mballoc.h"
48 
49 #define CREATE_TRACE_POINTS
50 #include <trace/events/ext4.h>
51 
52 struct proc_dir_entry *ext4_proc_root;
53 static struct kset *ext4_kset;
54 
55 static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
56 			     unsigned long journal_devnum);
57 static int ext4_commit_super(struct super_block *sb, int sync);
58 static void ext4_mark_recovery_complete(struct super_block *sb,
59 					struct ext4_super_block *es);
60 static void ext4_clear_journal_err(struct super_block *sb,
61 				   struct ext4_super_block *es);
62 static int ext4_sync_fs(struct super_block *sb, int wait);
63 static const char *ext4_decode_error(struct super_block *sb, int errno,
64 				     char nbuf[16]);
65 static int ext4_remount(struct super_block *sb, int *flags, char *data);
66 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf);
67 static int ext4_unfreeze(struct super_block *sb);
68 static void ext4_write_super(struct super_block *sb);
69 static int ext4_freeze(struct super_block *sb);
70 static int ext4_get_sb(struct file_system_type *fs_type, int flags,
71 		       const char *dev_name, void *data, struct vfsmount *mnt);
72 
73 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
74 static struct file_system_type ext3_fs_type = {
75 	.owner		= THIS_MODULE,
76 	.name		= "ext3",
77 	.get_sb		= ext4_get_sb,
78 	.kill_sb	= kill_block_super,
79 	.fs_flags	= FS_REQUIRES_DEV,
80 };
81 #define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type)
82 #else
83 #define IS_EXT3_SB(sb) (0)
84 #endif
85 
86 ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
87 			       struct ext4_group_desc *bg)
88 {
89 	return le32_to_cpu(bg->bg_block_bitmap_lo) |
90 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
91 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_block_bitmap_hi) << 32 : 0);
92 }
93 
94 ext4_fsblk_t ext4_inode_bitmap(struct super_block *sb,
95 			       struct ext4_group_desc *bg)
96 {
97 	return le32_to_cpu(bg->bg_inode_bitmap_lo) |
98 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
99 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_bitmap_hi) << 32 : 0);
100 }
101 
102 ext4_fsblk_t ext4_inode_table(struct super_block *sb,
103 			      struct ext4_group_desc *bg)
104 {
105 	return le32_to_cpu(bg->bg_inode_table_lo) |
106 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
107 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_table_hi) << 32 : 0);
108 }
109 
110 __u32 ext4_free_blks_count(struct super_block *sb,
111 			      struct ext4_group_desc *bg)
112 {
113 	return le16_to_cpu(bg->bg_free_blocks_count_lo) |
114 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
115 		 (__u32)le16_to_cpu(bg->bg_free_blocks_count_hi) << 16 : 0);
116 }
117 
118 __u32 ext4_free_inodes_count(struct super_block *sb,
119 			      struct ext4_group_desc *bg)
120 {
121 	return le16_to_cpu(bg->bg_free_inodes_count_lo) |
122 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
123 		 (__u32)le16_to_cpu(bg->bg_free_inodes_count_hi) << 16 : 0);
124 }
125 
126 __u32 ext4_used_dirs_count(struct super_block *sb,
127 			      struct ext4_group_desc *bg)
128 {
129 	return le16_to_cpu(bg->bg_used_dirs_count_lo) |
130 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
131 		 (__u32)le16_to_cpu(bg->bg_used_dirs_count_hi) << 16 : 0);
132 }
133 
134 __u32 ext4_itable_unused_count(struct super_block *sb,
135 			      struct ext4_group_desc *bg)
136 {
137 	return le16_to_cpu(bg->bg_itable_unused_lo) |
138 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
139 		 (__u32)le16_to_cpu(bg->bg_itable_unused_hi) << 16 : 0);
140 }
141 
142 void ext4_block_bitmap_set(struct super_block *sb,
143 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
144 {
145 	bg->bg_block_bitmap_lo = cpu_to_le32((u32)blk);
146 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
147 		bg->bg_block_bitmap_hi = cpu_to_le32(blk >> 32);
148 }
149 
150 void ext4_inode_bitmap_set(struct super_block *sb,
151 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
152 {
153 	bg->bg_inode_bitmap_lo  = cpu_to_le32((u32)blk);
154 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
155 		bg->bg_inode_bitmap_hi = cpu_to_le32(blk >> 32);
156 }
157 
158 void ext4_inode_table_set(struct super_block *sb,
159 			  struct ext4_group_desc *bg, ext4_fsblk_t blk)
160 {
161 	bg->bg_inode_table_lo = cpu_to_le32((u32)blk);
162 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
163 		bg->bg_inode_table_hi = cpu_to_le32(blk >> 32);
164 }
165 
166 void ext4_free_blks_set(struct super_block *sb,
167 			  struct ext4_group_desc *bg, __u32 count)
168 {
169 	bg->bg_free_blocks_count_lo = cpu_to_le16((__u16)count);
170 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
171 		bg->bg_free_blocks_count_hi = cpu_to_le16(count >> 16);
172 }
173 
174 void ext4_free_inodes_set(struct super_block *sb,
175 			  struct ext4_group_desc *bg, __u32 count)
176 {
177 	bg->bg_free_inodes_count_lo = cpu_to_le16((__u16)count);
178 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
179 		bg->bg_free_inodes_count_hi = cpu_to_le16(count >> 16);
180 }
181 
182 void ext4_used_dirs_set(struct super_block *sb,
183 			  struct ext4_group_desc *bg, __u32 count)
184 {
185 	bg->bg_used_dirs_count_lo = cpu_to_le16((__u16)count);
186 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
187 		bg->bg_used_dirs_count_hi = cpu_to_le16(count >> 16);
188 }
189 
190 void ext4_itable_unused_set(struct super_block *sb,
191 			  struct ext4_group_desc *bg, __u32 count)
192 {
193 	bg->bg_itable_unused_lo = cpu_to_le16((__u16)count);
194 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
195 		bg->bg_itable_unused_hi = cpu_to_le16(count >> 16);
196 }
197 
198 
199 /* Just increment the non-pointer handle value */
200 static handle_t *ext4_get_nojournal(void)
201 {
202 	handle_t *handle = current->journal_info;
203 	unsigned long ref_cnt = (unsigned long)handle;
204 
205 	BUG_ON(ref_cnt >= EXT4_NOJOURNAL_MAX_REF_COUNT);
206 
207 	ref_cnt++;
208 	handle = (handle_t *)ref_cnt;
209 
210 	current->journal_info = handle;
211 	return handle;
212 }
213 
214 
215 /* Decrement the non-pointer handle value */
216 static void ext4_put_nojournal(handle_t *handle)
217 {
218 	unsigned long ref_cnt = (unsigned long)handle;
219 
220 	BUG_ON(ref_cnt == 0);
221 
222 	ref_cnt--;
223 	handle = (handle_t *)ref_cnt;
224 
225 	current->journal_info = handle;
226 }
227 
228 /*
229  * Wrappers for jbd2_journal_start/end.
230  *
231  * The only special thing we need to do here is to make sure that all
232  * journal_end calls result in the superblock being marked dirty, so
233  * that sync() will call the filesystem's write_super callback if
234  * appropriate.
235  */
236 handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
237 {
238 	journal_t *journal;
239 
240 	if (sb->s_flags & MS_RDONLY)
241 		return ERR_PTR(-EROFS);
242 
243 	vfs_check_frozen(sb, SB_FREEZE_TRANS);
244 	/* Special case here: if the journal has aborted behind our
245 	 * backs (eg. EIO in the commit thread), then we still need to
246 	 * take the FS itself readonly cleanly. */
247 	journal = EXT4_SB(sb)->s_journal;
248 	if (journal) {
249 		if (is_journal_aborted(journal)) {
250 			ext4_abort(sb, "Detected aborted journal");
251 			return ERR_PTR(-EROFS);
252 		}
253 		return jbd2_journal_start(journal, nblocks);
254 	}
255 	return ext4_get_nojournal();
256 }
257 
258 /*
259  * The only special thing we need to do here is to make sure that all
260  * jbd2_journal_stop calls result in the superblock being marked dirty, so
261  * that sync() will call the filesystem's write_super callback if
262  * appropriate.
263  */
264 int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle)
265 {
266 	struct super_block *sb;
267 	int err;
268 	int rc;
269 
270 	if (!ext4_handle_valid(handle)) {
271 		ext4_put_nojournal(handle);
272 		return 0;
273 	}
274 	sb = handle->h_transaction->t_journal->j_private;
275 	err = handle->h_err;
276 	rc = jbd2_journal_stop(handle);
277 
278 	if (!err)
279 		err = rc;
280 	if (err)
281 		__ext4_std_error(sb, where, line, err);
282 	return err;
283 }
284 
285 void ext4_journal_abort_handle(const char *caller, unsigned int line,
286 			       const char *err_fn, struct buffer_head *bh,
287 			       handle_t *handle, int err)
288 {
289 	char nbuf[16];
290 	const char *errstr = ext4_decode_error(NULL, err, nbuf);
291 
292 	BUG_ON(!ext4_handle_valid(handle));
293 
294 	if (bh)
295 		BUFFER_TRACE(bh, "abort");
296 
297 	if (!handle->h_err)
298 		handle->h_err = err;
299 
300 	if (is_handle_aborted(handle))
301 		return;
302 
303 	printk(KERN_ERR "%s:%d: aborting transaction: %s in %s\n",
304 	       caller, line, errstr, err_fn);
305 
306 	jbd2_journal_abort_handle(handle);
307 }
308 
309 static void __save_error_info(struct super_block *sb, const char *func,
310 			    unsigned int line)
311 {
312 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
313 
314 	EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
315 	es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
316 	es->s_last_error_time = cpu_to_le32(get_seconds());
317 	strncpy(es->s_last_error_func, func, sizeof(es->s_last_error_func));
318 	es->s_last_error_line = cpu_to_le32(line);
319 	if (!es->s_first_error_time) {
320 		es->s_first_error_time = es->s_last_error_time;
321 		strncpy(es->s_first_error_func, func,
322 			sizeof(es->s_first_error_func));
323 		es->s_first_error_line = cpu_to_le32(line);
324 		es->s_first_error_ino = es->s_last_error_ino;
325 		es->s_first_error_block = es->s_last_error_block;
326 	}
327 	/*
328 	 * Start the daily error reporting function if it hasn't been
329 	 * started already
330 	 */
331 	if (!es->s_error_count)
332 		mod_timer(&EXT4_SB(sb)->s_err_report, jiffies + 24*60*60*HZ);
333 	es->s_error_count = cpu_to_le32(le32_to_cpu(es->s_error_count) + 1);
334 }
335 
336 static void save_error_info(struct super_block *sb, const char *func,
337 			    unsigned int line)
338 {
339 	__save_error_info(sb, func, line);
340 	ext4_commit_super(sb, 1);
341 }
342 
343 
344 /* Deal with the reporting of failure conditions on a filesystem such as
345  * inconsistencies detected or read IO failures.
346  *
347  * On ext2, we can store the error state of the filesystem in the
348  * superblock.  That is not possible on ext4, because we may have other
349  * write ordering constraints on the superblock which prevent us from
350  * writing it out straight away; and given that the journal is about to
351  * be aborted, we can't rely on the current, or future, transactions to
352  * write out the superblock safely.
353  *
354  * We'll just use the jbd2_journal_abort() error code to record an error in
355  * the journal instead.  On recovery, the journal will complain about
356  * that error until we've noted it down and cleared it.
357  */
358 
359 static void ext4_handle_error(struct super_block *sb)
360 {
361 	if (sb->s_flags & MS_RDONLY)
362 		return;
363 
364 	if (!test_opt(sb, ERRORS_CONT)) {
365 		journal_t *journal = EXT4_SB(sb)->s_journal;
366 
367 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
368 		if (journal)
369 			jbd2_journal_abort(journal, -EIO);
370 	}
371 	if (test_opt(sb, ERRORS_RO)) {
372 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
373 		sb->s_flags |= MS_RDONLY;
374 	}
375 	if (test_opt(sb, ERRORS_PANIC))
376 		panic("EXT4-fs (device %s): panic forced after error\n",
377 			sb->s_id);
378 }
379 
380 void __ext4_error(struct super_block *sb, const char *function,
381 		  unsigned int line, const char *fmt, ...)
382 {
383 	va_list args;
384 
385 	va_start(args, fmt);
386 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: comm %s: ",
387 	       sb->s_id, function, line, current->comm);
388 	vprintk(fmt, args);
389 	printk("\n");
390 	va_end(args);
391 
392 	ext4_handle_error(sb);
393 }
394 
395 void ext4_error_inode(struct inode *inode, const char *function,
396 		      unsigned int line, ext4_fsblk_t block,
397 		      const char *fmt, ...)
398 {
399 	va_list args;
400 	struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
401 
402 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
403 	es->s_last_error_block = cpu_to_le64(block);
404 	save_error_info(inode->i_sb, function, line);
405 	va_start(args, fmt);
406 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: inode #%lu: ",
407 	       inode->i_sb->s_id, function, line, inode->i_ino);
408 	if (block)
409 		printk("block %llu: ", block);
410 	printk("comm %s: ", current->comm);
411 	vprintk(fmt, args);
412 	printk("\n");
413 	va_end(args);
414 
415 	ext4_handle_error(inode->i_sb);
416 }
417 
418 void ext4_error_file(struct file *file, const char *function,
419 		     unsigned int line, const char *fmt, ...)
420 {
421 	va_list args;
422 	struct ext4_super_block *es;
423 	struct inode *inode = file->f_dentry->d_inode;
424 	char pathname[80], *path;
425 
426 	es = EXT4_SB(inode->i_sb)->s_es;
427 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
428 	save_error_info(inode->i_sb, function, line);
429 	va_start(args, fmt);
430 	path = d_path(&(file->f_path), pathname, sizeof(pathname));
431 	if (!path)
432 		path = "(unknown)";
433 	printk(KERN_CRIT
434 	       "EXT4-fs error (device %s): %s:%d: inode #%lu "
435 	       "(comm %s path %s): ",
436 	       inode->i_sb->s_id, function, line, inode->i_ino,
437 	       current->comm, path);
438 	vprintk(fmt, args);
439 	printk("\n");
440 	va_end(args);
441 
442 	ext4_handle_error(inode->i_sb);
443 }
444 
445 static const char *ext4_decode_error(struct super_block *sb, int errno,
446 				     char nbuf[16])
447 {
448 	char *errstr = NULL;
449 
450 	switch (errno) {
451 	case -EIO:
452 		errstr = "IO failure";
453 		break;
454 	case -ENOMEM:
455 		errstr = "Out of memory";
456 		break;
457 	case -EROFS:
458 		if (!sb || (EXT4_SB(sb)->s_journal &&
459 			    EXT4_SB(sb)->s_journal->j_flags & JBD2_ABORT))
460 			errstr = "Journal has aborted";
461 		else
462 			errstr = "Readonly filesystem";
463 		break;
464 	default:
465 		/* If the caller passed in an extra buffer for unknown
466 		 * errors, textualise them now.  Else we just return
467 		 * NULL. */
468 		if (nbuf) {
469 			/* Check for truncated error codes... */
470 			if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
471 				errstr = nbuf;
472 		}
473 		break;
474 	}
475 
476 	return errstr;
477 }
478 
479 /* __ext4_std_error decodes expected errors from journaling functions
480  * automatically and invokes the appropriate error response.  */
481 
482 void __ext4_std_error(struct super_block *sb, const char *function,
483 		      unsigned int line, int errno)
484 {
485 	char nbuf[16];
486 	const char *errstr;
487 
488 	/* Special case: if the error is EROFS, and we're not already
489 	 * inside a transaction, then there's really no point in logging
490 	 * an error. */
491 	if (errno == -EROFS && journal_current_handle() == NULL &&
492 	    (sb->s_flags & MS_RDONLY))
493 		return;
494 
495 	errstr = ext4_decode_error(sb, errno, nbuf);
496 	printk(KERN_CRIT "EXT4-fs error (device %s) in %s:%d: %s\n",
497 	       sb->s_id, function, line, errstr);
498 	save_error_info(sb, function, line);
499 
500 	ext4_handle_error(sb);
501 }
502 
503 /*
504  * ext4_abort is a much stronger failure handler than ext4_error.  The
505  * abort function may be used to deal with unrecoverable failures such
506  * as journal IO errors or ENOMEM at a critical moment in log management.
507  *
508  * We unconditionally force the filesystem into an ABORT|READONLY state,
509  * unless the error response on the fs has been set to panic in which
510  * case we take the easy way out and panic immediately.
511  */
512 
513 void __ext4_abort(struct super_block *sb, const char *function,
514 		unsigned int line, const char *fmt, ...)
515 {
516 	va_list args;
517 
518 	save_error_info(sb, function, line);
519 	va_start(args, fmt);
520 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: ", sb->s_id,
521 	       function, line);
522 	vprintk(fmt, args);
523 	printk("\n");
524 	va_end(args);
525 
526 	if ((sb->s_flags & MS_RDONLY) == 0) {
527 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
528 		sb->s_flags |= MS_RDONLY;
529 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
530 		if (EXT4_SB(sb)->s_journal)
531 			jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
532 		save_error_info(sb, function, line);
533 	}
534 	if (test_opt(sb, ERRORS_PANIC))
535 		panic("EXT4-fs panic from previous error\n");
536 }
537 
538 void ext4_msg (struct super_block * sb, const char *prefix,
539 		   const char *fmt, ...)
540 {
541 	va_list args;
542 
543 	va_start(args, fmt);
544 	printk("%sEXT4-fs (%s): ", prefix, sb->s_id);
545 	vprintk(fmt, args);
546 	printk("\n");
547 	va_end(args);
548 }
549 
550 void __ext4_warning(struct super_block *sb, const char *function,
551 		    unsigned int line, const char *fmt, ...)
552 {
553 	va_list args;
554 
555 	va_start(args, fmt);
556 	printk(KERN_WARNING "EXT4-fs warning (device %s): %s:%d: ",
557 	       sb->s_id, function, line);
558 	vprintk(fmt, args);
559 	printk("\n");
560 	va_end(args);
561 }
562 
563 void __ext4_grp_locked_error(const char *function, unsigned int line,
564 			     struct super_block *sb, ext4_group_t grp,
565 			     unsigned long ino, ext4_fsblk_t block,
566 			     const char *fmt, ...)
567 __releases(bitlock)
568 __acquires(bitlock)
569 {
570 	va_list args;
571 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
572 
573 	es->s_last_error_ino = cpu_to_le32(ino);
574 	es->s_last_error_block = cpu_to_le64(block);
575 	__save_error_info(sb, function, line);
576 	va_start(args, fmt);
577 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: group %u",
578 	       sb->s_id, function, line, grp);
579 	if (ino)
580 		printk("inode %lu: ", ino);
581 	if (block)
582 		printk("block %llu:", (unsigned long long) block);
583 	vprintk(fmt, args);
584 	printk("\n");
585 	va_end(args);
586 
587 	if (test_opt(sb, ERRORS_CONT)) {
588 		ext4_commit_super(sb, 0);
589 		return;
590 	}
591 
592 	ext4_unlock_group(sb, grp);
593 	ext4_handle_error(sb);
594 	/*
595 	 * We only get here in the ERRORS_RO case; relocking the group
596 	 * may be dangerous, but nothing bad will happen since the
597 	 * filesystem will have already been marked read/only and the
598 	 * journal has been aborted.  We return 1 as a hint to callers
599 	 * who might what to use the return value from
600 	 * ext4_grp_locked_error() to distinguish beween the
601 	 * ERRORS_CONT and ERRORS_RO case, and perhaps return more
602 	 * aggressively from the ext4 function in question, with a
603 	 * more appropriate error code.
604 	 */
605 	ext4_lock_group(sb, grp);
606 	return;
607 }
608 
609 void ext4_update_dynamic_rev(struct super_block *sb)
610 {
611 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
612 
613 	if (le32_to_cpu(es->s_rev_level) > EXT4_GOOD_OLD_REV)
614 		return;
615 
616 	ext4_warning(sb,
617 		     "updating to rev %d because of new feature flag, "
618 		     "running e2fsck is recommended",
619 		     EXT4_DYNAMIC_REV);
620 
621 	es->s_first_ino = cpu_to_le32(EXT4_GOOD_OLD_FIRST_INO);
622 	es->s_inode_size = cpu_to_le16(EXT4_GOOD_OLD_INODE_SIZE);
623 	es->s_rev_level = cpu_to_le32(EXT4_DYNAMIC_REV);
624 	/* leave es->s_feature_*compat flags alone */
625 	/* es->s_uuid will be set by e2fsck if empty */
626 
627 	/*
628 	 * The rest of the superblock fields should be zero, and if not it
629 	 * means they are likely already in use, so leave them alone.  We
630 	 * can leave it up to e2fsck to clean up any inconsistencies there.
631 	 */
632 }
633 
634 /*
635  * Open the external journal device
636  */
637 static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb)
638 {
639 	struct block_device *bdev;
640 	char b[BDEVNAME_SIZE];
641 
642 	bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
643 	if (IS_ERR(bdev))
644 		goto fail;
645 	return bdev;
646 
647 fail:
648 	ext4_msg(sb, KERN_ERR, "failed to open journal device %s: %ld",
649 			__bdevname(dev, b), PTR_ERR(bdev));
650 	return NULL;
651 }
652 
653 /*
654  * Release the journal device
655  */
656 static int ext4_blkdev_put(struct block_device *bdev)
657 {
658 	bd_release(bdev);
659 	return blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
660 }
661 
662 static int ext4_blkdev_remove(struct ext4_sb_info *sbi)
663 {
664 	struct block_device *bdev;
665 	int ret = -ENODEV;
666 
667 	bdev = sbi->journal_bdev;
668 	if (bdev) {
669 		ret = ext4_blkdev_put(bdev);
670 		sbi->journal_bdev = NULL;
671 	}
672 	return ret;
673 }
674 
675 static inline struct inode *orphan_list_entry(struct list_head *l)
676 {
677 	return &list_entry(l, struct ext4_inode_info, i_orphan)->vfs_inode;
678 }
679 
680 static void dump_orphan_list(struct super_block *sb, struct ext4_sb_info *sbi)
681 {
682 	struct list_head *l;
683 
684 	ext4_msg(sb, KERN_ERR, "sb orphan head is %d",
685 		 le32_to_cpu(sbi->s_es->s_last_orphan));
686 
687 	printk(KERN_ERR "sb_info orphan list:\n");
688 	list_for_each(l, &sbi->s_orphan) {
689 		struct inode *inode = orphan_list_entry(l);
690 		printk(KERN_ERR "  "
691 		       "inode %s:%lu at %p: mode %o, nlink %d, next %d\n",
692 		       inode->i_sb->s_id, inode->i_ino, inode,
693 		       inode->i_mode, inode->i_nlink,
694 		       NEXT_ORPHAN(inode));
695 	}
696 }
697 
698 static void ext4_put_super(struct super_block *sb)
699 {
700 	struct ext4_sb_info *sbi = EXT4_SB(sb);
701 	struct ext4_super_block *es = sbi->s_es;
702 	int i, err;
703 
704 	dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
705 
706 	flush_workqueue(sbi->dio_unwritten_wq);
707 	destroy_workqueue(sbi->dio_unwritten_wq);
708 
709 	lock_super(sb);
710 	if (sb->s_dirt)
711 		ext4_commit_super(sb, 1);
712 
713 	if (sbi->s_journal) {
714 		err = jbd2_journal_destroy(sbi->s_journal);
715 		sbi->s_journal = NULL;
716 		if (err < 0)
717 			ext4_abort(sb, "Couldn't clean up the journal");
718 	}
719 
720 	ext4_release_system_zone(sb);
721 	ext4_mb_release(sb);
722 	ext4_ext_release(sb);
723 	ext4_xattr_put_super(sb);
724 
725 	if (!(sb->s_flags & MS_RDONLY)) {
726 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
727 		es->s_state = cpu_to_le16(sbi->s_mount_state);
728 		ext4_commit_super(sb, 1);
729 	}
730 	if (sbi->s_proc) {
731 		remove_proc_entry(sb->s_id, ext4_proc_root);
732 	}
733 	kobject_del(&sbi->s_kobj);
734 
735 	for (i = 0; i < sbi->s_gdb_count; i++)
736 		brelse(sbi->s_group_desc[i]);
737 	kfree(sbi->s_group_desc);
738 	if (is_vmalloc_addr(sbi->s_flex_groups))
739 		vfree(sbi->s_flex_groups);
740 	else
741 		kfree(sbi->s_flex_groups);
742 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
743 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
744 	percpu_counter_destroy(&sbi->s_dirs_counter);
745 	percpu_counter_destroy(&sbi->s_dirtyblocks_counter);
746 	brelse(sbi->s_sbh);
747 #ifdef CONFIG_QUOTA
748 	for (i = 0; i < MAXQUOTAS; i++)
749 		kfree(sbi->s_qf_names[i]);
750 #endif
751 
752 	/* Debugging code just in case the in-memory inode orphan list
753 	 * isn't empty.  The on-disk one can be non-empty if we've
754 	 * detected an error and taken the fs readonly, but the
755 	 * in-memory list had better be clean by this point. */
756 	if (!list_empty(&sbi->s_orphan))
757 		dump_orphan_list(sb, sbi);
758 	J_ASSERT(list_empty(&sbi->s_orphan));
759 
760 	invalidate_bdev(sb->s_bdev);
761 	if (sbi->journal_bdev && sbi->journal_bdev != sb->s_bdev) {
762 		/*
763 		 * Invalidate the journal device's buffers.  We don't want them
764 		 * floating about in memory - the physical journal device may
765 		 * hotswapped, and it breaks the `ro-after' testing code.
766 		 */
767 		sync_blockdev(sbi->journal_bdev);
768 		invalidate_bdev(sbi->journal_bdev);
769 		ext4_blkdev_remove(sbi);
770 	}
771 	sb->s_fs_info = NULL;
772 	/*
773 	 * Now that we are completely done shutting down the
774 	 * superblock, we need to actually destroy the kobject.
775 	 */
776 	unlock_super(sb);
777 	kobject_put(&sbi->s_kobj);
778 	wait_for_completion(&sbi->s_kobj_unregister);
779 	kfree(sbi->s_blockgroup_lock);
780 	kfree(sbi);
781 }
782 
783 static struct kmem_cache *ext4_inode_cachep;
784 
785 /*
786  * Called inside transaction, so use GFP_NOFS
787  */
788 static struct inode *ext4_alloc_inode(struct super_block *sb)
789 {
790 	struct ext4_inode_info *ei;
791 
792 	ei = kmem_cache_alloc(ext4_inode_cachep, GFP_NOFS);
793 	if (!ei)
794 		return NULL;
795 
796 	ei->vfs_inode.i_version = 1;
797 	ei->vfs_inode.i_data.writeback_index = 0;
798 	memset(&ei->i_cached_extent, 0, sizeof(struct ext4_ext_cache));
799 	INIT_LIST_HEAD(&ei->i_prealloc_list);
800 	spin_lock_init(&ei->i_prealloc_lock);
801 	/*
802 	 * Note:  We can be called before EXT4_SB(sb)->s_journal is set,
803 	 * therefore it can be null here.  Don't check it, just initialize
804 	 * jinode.
805 	 */
806 	jbd2_journal_init_jbd_inode(&ei->jinode, &ei->vfs_inode);
807 	ei->i_reserved_data_blocks = 0;
808 	ei->i_reserved_meta_blocks = 0;
809 	ei->i_allocated_meta_blocks = 0;
810 	ei->i_da_metadata_calc_len = 0;
811 	ei->i_delalloc_reserved_flag = 0;
812 	spin_lock_init(&(ei->i_block_reservation_lock));
813 #ifdef CONFIG_QUOTA
814 	ei->i_reserved_quota = 0;
815 #endif
816 	INIT_LIST_HEAD(&ei->i_completed_io_list);
817 	spin_lock_init(&ei->i_completed_io_lock);
818 	ei->cur_aio_dio = NULL;
819 	ei->i_sync_tid = 0;
820 	ei->i_datasync_tid = 0;
821 
822 	return &ei->vfs_inode;
823 }
824 
825 static void ext4_destroy_inode(struct inode *inode)
826 {
827 	if (!list_empty(&(EXT4_I(inode)->i_orphan))) {
828 		ext4_msg(inode->i_sb, KERN_ERR,
829 			 "Inode %lu (%p): orphan list check failed!",
830 			 inode->i_ino, EXT4_I(inode));
831 		print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 16, 4,
832 				EXT4_I(inode), sizeof(struct ext4_inode_info),
833 				true);
834 		dump_stack();
835 	}
836 	kmem_cache_free(ext4_inode_cachep, EXT4_I(inode));
837 }
838 
839 static void init_once(void *foo)
840 {
841 	struct ext4_inode_info *ei = (struct ext4_inode_info *) foo;
842 
843 	INIT_LIST_HEAD(&ei->i_orphan);
844 #ifdef CONFIG_EXT4_FS_XATTR
845 	init_rwsem(&ei->xattr_sem);
846 #endif
847 	init_rwsem(&ei->i_data_sem);
848 	inode_init_once(&ei->vfs_inode);
849 }
850 
851 static int init_inodecache(void)
852 {
853 	ext4_inode_cachep = kmem_cache_create("ext4_inode_cache",
854 					     sizeof(struct ext4_inode_info),
855 					     0, (SLAB_RECLAIM_ACCOUNT|
856 						SLAB_MEM_SPREAD),
857 					     init_once);
858 	if (ext4_inode_cachep == NULL)
859 		return -ENOMEM;
860 	return 0;
861 }
862 
863 static void destroy_inodecache(void)
864 {
865 	kmem_cache_destroy(ext4_inode_cachep);
866 }
867 
868 void ext4_clear_inode(struct inode *inode)
869 {
870 	invalidate_inode_buffers(inode);
871 	end_writeback(inode);
872 	dquot_drop(inode);
873 	ext4_discard_preallocations(inode);
874 	if (EXT4_JOURNAL(inode))
875 		jbd2_journal_release_jbd_inode(EXT4_SB(inode->i_sb)->s_journal,
876 				       &EXT4_I(inode)->jinode);
877 }
878 
879 static inline void ext4_show_quota_options(struct seq_file *seq,
880 					   struct super_block *sb)
881 {
882 #if defined(CONFIG_QUOTA)
883 	struct ext4_sb_info *sbi = EXT4_SB(sb);
884 
885 	if (sbi->s_jquota_fmt) {
886 		char *fmtname = "";
887 
888 		switch (sbi->s_jquota_fmt) {
889 		case QFMT_VFS_OLD:
890 			fmtname = "vfsold";
891 			break;
892 		case QFMT_VFS_V0:
893 			fmtname = "vfsv0";
894 			break;
895 		case QFMT_VFS_V1:
896 			fmtname = "vfsv1";
897 			break;
898 		}
899 		seq_printf(seq, ",jqfmt=%s", fmtname);
900 	}
901 
902 	if (sbi->s_qf_names[USRQUOTA])
903 		seq_printf(seq, ",usrjquota=%s", sbi->s_qf_names[USRQUOTA]);
904 
905 	if (sbi->s_qf_names[GRPQUOTA])
906 		seq_printf(seq, ",grpjquota=%s", sbi->s_qf_names[GRPQUOTA]);
907 
908 	if (test_opt(sb, USRQUOTA))
909 		seq_puts(seq, ",usrquota");
910 
911 	if (test_opt(sb, GRPQUOTA))
912 		seq_puts(seq, ",grpquota");
913 #endif
914 }
915 
916 /*
917  * Show an option if
918  *  - it's set to a non-default value OR
919  *  - if the per-sb default is different from the global default
920  */
921 static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs)
922 {
923 	int def_errors;
924 	unsigned long def_mount_opts;
925 	struct super_block *sb = vfs->mnt_sb;
926 	struct ext4_sb_info *sbi = EXT4_SB(sb);
927 	struct ext4_super_block *es = sbi->s_es;
928 
929 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
930 	def_errors     = le16_to_cpu(es->s_errors);
931 
932 	if (sbi->s_sb_block != 1)
933 		seq_printf(seq, ",sb=%llu", sbi->s_sb_block);
934 	if (test_opt(sb, MINIX_DF))
935 		seq_puts(seq, ",minixdf");
936 	if (test_opt(sb, GRPID) && !(def_mount_opts & EXT4_DEFM_BSDGROUPS))
937 		seq_puts(seq, ",grpid");
938 	if (!test_opt(sb, GRPID) && (def_mount_opts & EXT4_DEFM_BSDGROUPS))
939 		seq_puts(seq, ",nogrpid");
940 	if (sbi->s_resuid != EXT4_DEF_RESUID ||
941 	    le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID) {
942 		seq_printf(seq, ",resuid=%u", sbi->s_resuid);
943 	}
944 	if (sbi->s_resgid != EXT4_DEF_RESGID ||
945 	    le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID) {
946 		seq_printf(seq, ",resgid=%u", sbi->s_resgid);
947 	}
948 	if (test_opt(sb, ERRORS_RO)) {
949 		if (def_errors == EXT4_ERRORS_PANIC ||
950 		    def_errors == EXT4_ERRORS_CONTINUE) {
951 			seq_puts(seq, ",errors=remount-ro");
952 		}
953 	}
954 	if (test_opt(sb, ERRORS_CONT) && def_errors != EXT4_ERRORS_CONTINUE)
955 		seq_puts(seq, ",errors=continue");
956 	if (test_opt(sb, ERRORS_PANIC) && def_errors != EXT4_ERRORS_PANIC)
957 		seq_puts(seq, ",errors=panic");
958 	if (test_opt(sb, NO_UID32) && !(def_mount_opts & EXT4_DEFM_UID16))
959 		seq_puts(seq, ",nouid32");
960 	if (test_opt(sb, DEBUG) && !(def_mount_opts & EXT4_DEFM_DEBUG))
961 		seq_puts(seq, ",debug");
962 	if (test_opt(sb, OLDALLOC))
963 		seq_puts(seq, ",oldalloc");
964 #ifdef CONFIG_EXT4_FS_XATTR
965 	if (test_opt(sb, XATTR_USER) &&
966 		!(def_mount_opts & EXT4_DEFM_XATTR_USER))
967 		seq_puts(seq, ",user_xattr");
968 	if (!test_opt(sb, XATTR_USER) &&
969 	    (def_mount_opts & EXT4_DEFM_XATTR_USER)) {
970 		seq_puts(seq, ",nouser_xattr");
971 	}
972 #endif
973 #ifdef CONFIG_EXT4_FS_POSIX_ACL
974 	if (test_opt(sb, POSIX_ACL) && !(def_mount_opts & EXT4_DEFM_ACL))
975 		seq_puts(seq, ",acl");
976 	if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT4_DEFM_ACL))
977 		seq_puts(seq, ",noacl");
978 #endif
979 	if (sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ) {
980 		seq_printf(seq, ",commit=%u",
981 			   (unsigned) (sbi->s_commit_interval / HZ));
982 	}
983 	if (sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME) {
984 		seq_printf(seq, ",min_batch_time=%u",
985 			   (unsigned) sbi->s_min_batch_time);
986 	}
987 	if (sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME) {
988 		seq_printf(seq, ",max_batch_time=%u",
989 			   (unsigned) sbi->s_min_batch_time);
990 	}
991 
992 	/*
993 	 * We're changing the default of barrier mount option, so
994 	 * let's always display its mount state so it's clear what its
995 	 * status is.
996 	 */
997 	seq_puts(seq, ",barrier=");
998 	seq_puts(seq, test_opt(sb, BARRIER) ? "1" : "0");
999 	if (test_opt(sb, JOURNAL_ASYNC_COMMIT))
1000 		seq_puts(seq, ",journal_async_commit");
1001 	else if (test_opt(sb, JOURNAL_CHECKSUM))
1002 		seq_puts(seq, ",journal_checksum");
1003 	if (test_opt(sb, I_VERSION))
1004 		seq_puts(seq, ",i_version");
1005 	if (!test_opt(sb, DELALLOC) &&
1006 	    !(def_mount_opts & EXT4_DEFM_NODELALLOC))
1007 		seq_puts(seq, ",nodelalloc");
1008 
1009 	if (sbi->s_stripe)
1010 		seq_printf(seq, ",stripe=%lu", sbi->s_stripe);
1011 	/*
1012 	 * journal mode get enabled in different ways
1013 	 * So just print the value even if we didn't specify it
1014 	 */
1015 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
1016 		seq_puts(seq, ",data=journal");
1017 	else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
1018 		seq_puts(seq, ",data=ordered");
1019 	else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
1020 		seq_puts(seq, ",data=writeback");
1021 
1022 	if (sbi->s_inode_readahead_blks != EXT4_DEF_INODE_READAHEAD_BLKS)
1023 		seq_printf(seq, ",inode_readahead_blks=%u",
1024 			   sbi->s_inode_readahead_blks);
1025 
1026 	if (test_opt(sb, DATA_ERR_ABORT))
1027 		seq_puts(seq, ",data_err=abort");
1028 
1029 	if (test_opt(sb, NO_AUTO_DA_ALLOC))
1030 		seq_puts(seq, ",noauto_da_alloc");
1031 
1032 	if (test_opt(sb, DISCARD) && !(def_mount_opts & EXT4_DEFM_DISCARD))
1033 		seq_puts(seq, ",discard");
1034 
1035 	if (test_opt(sb, NOLOAD))
1036 		seq_puts(seq, ",norecovery");
1037 
1038 	if (test_opt(sb, DIOREAD_NOLOCK))
1039 		seq_puts(seq, ",dioread_nolock");
1040 
1041 	if (test_opt(sb, BLOCK_VALIDITY) &&
1042 	    !(def_mount_opts & EXT4_DEFM_BLOCK_VALIDITY))
1043 		seq_puts(seq, ",block_validity");
1044 
1045 	ext4_show_quota_options(seq, sb);
1046 
1047 	return 0;
1048 }
1049 
1050 static struct inode *ext4_nfs_get_inode(struct super_block *sb,
1051 					u64 ino, u32 generation)
1052 {
1053 	struct inode *inode;
1054 
1055 	if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
1056 		return ERR_PTR(-ESTALE);
1057 	if (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
1058 		return ERR_PTR(-ESTALE);
1059 
1060 	/* iget isn't really right if the inode is currently unallocated!!
1061 	 *
1062 	 * ext4_read_inode will return a bad_inode if the inode had been
1063 	 * deleted, so we should be safe.
1064 	 *
1065 	 * Currently we don't know the generation for parent directory, so
1066 	 * a generation of 0 means "accept any"
1067 	 */
1068 	inode = ext4_iget(sb, ino);
1069 	if (IS_ERR(inode))
1070 		return ERR_CAST(inode);
1071 	if (generation && inode->i_generation != generation) {
1072 		iput(inode);
1073 		return ERR_PTR(-ESTALE);
1074 	}
1075 
1076 	return inode;
1077 }
1078 
1079 static struct dentry *ext4_fh_to_dentry(struct super_block *sb, struct fid *fid,
1080 					int fh_len, int fh_type)
1081 {
1082 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
1083 				    ext4_nfs_get_inode);
1084 }
1085 
1086 static struct dentry *ext4_fh_to_parent(struct super_block *sb, struct fid *fid,
1087 					int fh_len, int fh_type)
1088 {
1089 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
1090 				    ext4_nfs_get_inode);
1091 }
1092 
1093 /*
1094  * Try to release metadata pages (indirect blocks, directories) which are
1095  * mapped via the block device.  Since these pages could have journal heads
1096  * which would prevent try_to_free_buffers() from freeing them, we must use
1097  * jbd2 layer's try_to_free_buffers() function to release them.
1098  */
1099 static int bdev_try_to_free_page(struct super_block *sb, struct page *page,
1100 				 gfp_t wait)
1101 {
1102 	journal_t *journal = EXT4_SB(sb)->s_journal;
1103 
1104 	WARN_ON(PageChecked(page));
1105 	if (!page_has_buffers(page))
1106 		return 0;
1107 	if (journal)
1108 		return jbd2_journal_try_to_free_buffers(journal, page,
1109 							wait & ~__GFP_WAIT);
1110 	return try_to_free_buffers(page);
1111 }
1112 
1113 #ifdef CONFIG_QUOTA
1114 #define QTYPE2NAME(t) ((t) == USRQUOTA ? "user" : "group")
1115 #define QTYPE2MOPT(on, t) ((t) == USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
1116 
1117 static int ext4_write_dquot(struct dquot *dquot);
1118 static int ext4_acquire_dquot(struct dquot *dquot);
1119 static int ext4_release_dquot(struct dquot *dquot);
1120 static int ext4_mark_dquot_dirty(struct dquot *dquot);
1121 static int ext4_write_info(struct super_block *sb, int type);
1122 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
1123 				char *path);
1124 static int ext4_quota_off(struct super_block *sb, int type);
1125 static int ext4_quota_on_mount(struct super_block *sb, int type);
1126 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
1127 			       size_t len, loff_t off);
1128 static ssize_t ext4_quota_write(struct super_block *sb, int type,
1129 				const char *data, size_t len, loff_t off);
1130 
1131 static const struct dquot_operations ext4_quota_operations = {
1132 #ifdef CONFIG_QUOTA
1133 	.get_reserved_space = ext4_get_reserved_space,
1134 #endif
1135 	.write_dquot	= ext4_write_dquot,
1136 	.acquire_dquot	= ext4_acquire_dquot,
1137 	.release_dquot	= ext4_release_dquot,
1138 	.mark_dirty	= ext4_mark_dquot_dirty,
1139 	.write_info	= ext4_write_info,
1140 	.alloc_dquot	= dquot_alloc,
1141 	.destroy_dquot	= dquot_destroy,
1142 };
1143 
1144 static const struct quotactl_ops ext4_qctl_operations = {
1145 	.quota_on	= ext4_quota_on,
1146 	.quota_off	= ext4_quota_off,
1147 	.quota_sync	= dquot_quota_sync,
1148 	.get_info	= dquot_get_dqinfo,
1149 	.set_info	= dquot_set_dqinfo,
1150 	.get_dqblk	= dquot_get_dqblk,
1151 	.set_dqblk	= dquot_set_dqblk
1152 };
1153 #endif
1154 
1155 static const struct super_operations ext4_sops = {
1156 	.alloc_inode	= ext4_alloc_inode,
1157 	.destroy_inode	= ext4_destroy_inode,
1158 	.write_inode	= ext4_write_inode,
1159 	.dirty_inode	= ext4_dirty_inode,
1160 	.evict_inode	= ext4_evict_inode,
1161 	.put_super	= ext4_put_super,
1162 	.sync_fs	= ext4_sync_fs,
1163 	.freeze_fs	= ext4_freeze,
1164 	.unfreeze_fs	= ext4_unfreeze,
1165 	.statfs		= ext4_statfs,
1166 	.remount_fs	= ext4_remount,
1167 	.show_options	= ext4_show_options,
1168 #ifdef CONFIG_QUOTA
1169 	.quota_read	= ext4_quota_read,
1170 	.quota_write	= ext4_quota_write,
1171 #endif
1172 	.bdev_try_to_free_page = bdev_try_to_free_page,
1173 };
1174 
1175 static const struct super_operations ext4_nojournal_sops = {
1176 	.alloc_inode	= ext4_alloc_inode,
1177 	.destroy_inode	= ext4_destroy_inode,
1178 	.write_inode	= ext4_write_inode,
1179 	.dirty_inode	= ext4_dirty_inode,
1180 	.evict_inode	= ext4_evict_inode,
1181 	.write_super	= ext4_write_super,
1182 	.put_super	= ext4_put_super,
1183 	.statfs		= ext4_statfs,
1184 	.remount_fs	= ext4_remount,
1185 	.show_options	= ext4_show_options,
1186 #ifdef CONFIG_QUOTA
1187 	.quota_read	= ext4_quota_read,
1188 	.quota_write	= ext4_quota_write,
1189 #endif
1190 	.bdev_try_to_free_page = bdev_try_to_free_page,
1191 };
1192 
1193 static const struct export_operations ext4_export_ops = {
1194 	.fh_to_dentry = ext4_fh_to_dentry,
1195 	.fh_to_parent = ext4_fh_to_parent,
1196 	.get_parent = ext4_get_parent,
1197 };
1198 
1199 enum {
1200 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
1201 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
1202 	Opt_nouid32, Opt_debug, Opt_oldalloc, Opt_orlov,
1203 	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
1204 	Opt_auto_da_alloc, Opt_noauto_da_alloc, Opt_noload, Opt_nobh, Opt_bh,
1205 	Opt_commit, Opt_min_batch_time, Opt_max_batch_time,
1206 	Opt_journal_update, Opt_journal_dev,
1207 	Opt_journal_checksum, Opt_journal_async_commit,
1208 	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
1209 	Opt_data_err_abort, Opt_data_err_ignore,
1210 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
1211 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
1212 	Opt_noquota, Opt_ignore, Opt_barrier, Opt_nobarrier, Opt_err,
1213 	Opt_resize, Opt_usrquota, Opt_grpquota, Opt_i_version,
1214 	Opt_stripe, Opt_delalloc, Opt_nodelalloc,
1215 	Opt_block_validity, Opt_noblock_validity,
1216 	Opt_inode_readahead_blks, Opt_journal_ioprio,
1217 	Opt_dioread_nolock, Opt_dioread_lock,
1218 	Opt_discard, Opt_nodiscard,
1219 };
1220 
1221 static const match_table_t tokens = {
1222 	{Opt_bsd_df, "bsddf"},
1223 	{Opt_minix_df, "minixdf"},
1224 	{Opt_grpid, "grpid"},
1225 	{Opt_grpid, "bsdgroups"},
1226 	{Opt_nogrpid, "nogrpid"},
1227 	{Opt_nogrpid, "sysvgroups"},
1228 	{Opt_resgid, "resgid=%u"},
1229 	{Opt_resuid, "resuid=%u"},
1230 	{Opt_sb, "sb=%u"},
1231 	{Opt_err_cont, "errors=continue"},
1232 	{Opt_err_panic, "errors=panic"},
1233 	{Opt_err_ro, "errors=remount-ro"},
1234 	{Opt_nouid32, "nouid32"},
1235 	{Opt_debug, "debug"},
1236 	{Opt_oldalloc, "oldalloc"},
1237 	{Opt_orlov, "orlov"},
1238 	{Opt_user_xattr, "user_xattr"},
1239 	{Opt_nouser_xattr, "nouser_xattr"},
1240 	{Opt_acl, "acl"},
1241 	{Opt_noacl, "noacl"},
1242 	{Opt_noload, "noload"},
1243 	{Opt_noload, "norecovery"},
1244 	{Opt_nobh, "nobh"},
1245 	{Opt_bh, "bh"},
1246 	{Opt_commit, "commit=%u"},
1247 	{Opt_min_batch_time, "min_batch_time=%u"},
1248 	{Opt_max_batch_time, "max_batch_time=%u"},
1249 	{Opt_journal_update, "journal=update"},
1250 	{Opt_journal_dev, "journal_dev=%u"},
1251 	{Opt_journal_checksum, "journal_checksum"},
1252 	{Opt_journal_async_commit, "journal_async_commit"},
1253 	{Opt_abort, "abort"},
1254 	{Opt_data_journal, "data=journal"},
1255 	{Opt_data_ordered, "data=ordered"},
1256 	{Opt_data_writeback, "data=writeback"},
1257 	{Opt_data_err_abort, "data_err=abort"},
1258 	{Opt_data_err_ignore, "data_err=ignore"},
1259 	{Opt_offusrjquota, "usrjquota="},
1260 	{Opt_usrjquota, "usrjquota=%s"},
1261 	{Opt_offgrpjquota, "grpjquota="},
1262 	{Opt_grpjquota, "grpjquota=%s"},
1263 	{Opt_jqfmt_vfsold, "jqfmt=vfsold"},
1264 	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
1265 	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
1266 	{Opt_grpquota, "grpquota"},
1267 	{Opt_noquota, "noquota"},
1268 	{Opt_quota, "quota"},
1269 	{Opt_usrquota, "usrquota"},
1270 	{Opt_barrier, "barrier=%u"},
1271 	{Opt_barrier, "barrier"},
1272 	{Opt_nobarrier, "nobarrier"},
1273 	{Opt_i_version, "i_version"},
1274 	{Opt_stripe, "stripe=%u"},
1275 	{Opt_resize, "resize"},
1276 	{Opt_delalloc, "delalloc"},
1277 	{Opt_nodelalloc, "nodelalloc"},
1278 	{Opt_block_validity, "block_validity"},
1279 	{Opt_noblock_validity, "noblock_validity"},
1280 	{Opt_inode_readahead_blks, "inode_readahead_blks=%u"},
1281 	{Opt_journal_ioprio, "journal_ioprio=%u"},
1282 	{Opt_auto_da_alloc, "auto_da_alloc=%u"},
1283 	{Opt_auto_da_alloc, "auto_da_alloc"},
1284 	{Opt_noauto_da_alloc, "noauto_da_alloc"},
1285 	{Opt_dioread_nolock, "dioread_nolock"},
1286 	{Opt_dioread_lock, "dioread_lock"},
1287 	{Opt_discard, "discard"},
1288 	{Opt_nodiscard, "nodiscard"},
1289 	{Opt_err, NULL},
1290 };
1291 
1292 static ext4_fsblk_t get_sb_block(void **data)
1293 {
1294 	ext4_fsblk_t	sb_block;
1295 	char		*options = (char *) *data;
1296 
1297 	if (!options || strncmp(options, "sb=", 3) != 0)
1298 		return 1;	/* Default location */
1299 
1300 	options += 3;
1301 	/* TODO: use simple_strtoll with >32bit ext4 */
1302 	sb_block = simple_strtoul(options, &options, 0);
1303 	if (*options && *options != ',') {
1304 		printk(KERN_ERR "EXT4-fs: Invalid sb specification: %s\n",
1305 		       (char *) *data);
1306 		return 1;
1307 	}
1308 	if (*options == ',')
1309 		options++;
1310 	*data = (void *) options;
1311 
1312 	return sb_block;
1313 }
1314 
1315 #define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))
1316 static char deprecated_msg[] = "Mount option \"%s\" will be removed by %s\n"
1317 	"Contact linux-ext4@vger.kernel.org if you think we should keep it.\n";
1318 
1319 #ifdef CONFIG_QUOTA
1320 static int set_qf_name(struct super_block *sb, int qtype, substring_t *args)
1321 {
1322 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1323 	char *qname;
1324 
1325 	if (sb_any_quota_loaded(sb) &&
1326 		!sbi->s_qf_names[qtype]) {
1327 		ext4_msg(sb, KERN_ERR,
1328 			"Cannot change journaled "
1329 			"quota options when quota turned on");
1330 		return 0;
1331 	}
1332 	qname = match_strdup(args);
1333 	if (!qname) {
1334 		ext4_msg(sb, KERN_ERR,
1335 			"Not enough memory for storing quotafile name");
1336 		return 0;
1337 	}
1338 	if (sbi->s_qf_names[qtype] &&
1339 		strcmp(sbi->s_qf_names[qtype], qname)) {
1340 		ext4_msg(sb, KERN_ERR,
1341 			"%s quota file already specified", QTYPE2NAME(qtype));
1342 		kfree(qname);
1343 		return 0;
1344 	}
1345 	sbi->s_qf_names[qtype] = qname;
1346 	if (strchr(sbi->s_qf_names[qtype], '/')) {
1347 		ext4_msg(sb, KERN_ERR,
1348 			"quotafile must be on filesystem root");
1349 		kfree(sbi->s_qf_names[qtype]);
1350 		sbi->s_qf_names[qtype] = NULL;
1351 		return 0;
1352 	}
1353 	set_opt(sbi->s_mount_opt, QUOTA);
1354 	return 1;
1355 }
1356 
1357 static int clear_qf_name(struct super_block *sb, int qtype)
1358 {
1359 
1360 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1361 
1362 	if (sb_any_quota_loaded(sb) &&
1363 		sbi->s_qf_names[qtype]) {
1364 		ext4_msg(sb, KERN_ERR, "Cannot change journaled quota options"
1365 			" when quota turned on");
1366 		return 0;
1367 	}
1368 	/*
1369 	 * The space will be released later when all options are confirmed
1370 	 * to be correct
1371 	 */
1372 	sbi->s_qf_names[qtype] = NULL;
1373 	return 1;
1374 }
1375 #endif
1376 
1377 static int parse_options(char *options, struct super_block *sb,
1378 			 unsigned long *journal_devnum,
1379 			 unsigned int *journal_ioprio,
1380 			 ext4_fsblk_t *n_blocks_count, int is_remount)
1381 {
1382 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1383 	char *p;
1384 	substring_t args[MAX_OPT_ARGS];
1385 	int data_opt = 0;
1386 	int option;
1387 #ifdef CONFIG_QUOTA
1388 	int qfmt;
1389 #endif
1390 
1391 	if (!options)
1392 		return 1;
1393 
1394 	while ((p = strsep(&options, ",")) != NULL) {
1395 		int token;
1396 		if (!*p)
1397 			continue;
1398 
1399 		/*
1400 		 * Initialize args struct so we know whether arg was
1401 		 * found; some options take optional arguments.
1402 		 */
1403 		args[0].to = args[0].from = 0;
1404 		token = match_token(p, tokens, args);
1405 		switch (token) {
1406 		case Opt_bsd_df:
1407 			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
1408 			clear_opt(sbi->s_mount_opt, MINIX_DF);
1409 			break;
1410 		case Opt_minix_df:
1411 			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
1412 			set_opt(sbi->s_mount_opt, MINIX_DF);
1413 
1414 			break;
1415 		case Opt_grpid:
1416 			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
1417 			set_opt(sbi->s_mount_opt, GRPID);
1418 
1419 			break;
1420 		case Opt_nogrpid:
1421 			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
1422 			clear_opt(sbi->s_mount_opt, GRPID);
1423 
1424 			break;
1425 		case Opt_resuid:
1426 			if (match_int(&args[0], &option))
1427 				return 0;
1428 			sbi->s_resuid = option;
1429 			break;
1430 		case Opt_resgid:
1431 			if (match_int(&args[0], &option))
1432 				return 0;
1433 			sbi->s_resgid = option;
1434 			break;
1435 		case Opt_sb:
1436 			/* handled by get_sb_block() instead of here */
1437 			/* *sb_block = match_int(&args[0]); */
1438 			break;
1439 		case Opt_err_panic:
1440 			clear_opt(sbi->s_mount_opt, ERRORS_CONT);
1441 			clear_opt(sbi->s_mount_opt, ERRORS_RO);
1442 			set_opt(sbi->s_mount_opt, ERRORS_PANIC);
1443 			break;
1444 		case Opt_err_ro:
1445 			clear_opt(sbi->s_mount_opt, ERRORS_CONT);
1446 			clear_opt(sbi->s_mount_opt, ERRORS_PANIC);
1447 			set_opt(sbi->s_mount_opt, ERRORS_RO);
1448 			break;
1449 		case Opt_err_cont:
1450 			clear_opt(sbi->s_mount_opt, ERRORS_RO);
1451 			clear_opt(sbi->s_mount_opt, ERRORS_PANIC);
1452 			set_opt(sbi->s_mount_opt, ERRORS_CONT);
1453 			break;
1454 		case Opt_nouid32:
1455 			set_opt(sbi->s_mount_opt, NO_UID32);
1456 			break;
1457 		case Opt_debug:
1458 			set_opt(sbi->s_mount_opt, DEBUG);
1459 			break;
1460 		case Opt_oldalloc:
1461 			set_opt(sbi->s_mount_opt, OLDALLOC);
1462 			break;
1463 		case Opt_orlov:
1464 			clear_opt(sbi->s_mount_opt, OLDALLOC);
1465 			break;
1466 #ifdef CONFIG_EXT4_FS_XATTR
1467 		case Opt_user_xattr:
1468 			set_opt(sbi->s_mount_opt, XATTR_USER);
1469 			break;
1470 		case Opt_nouser_xattr:
1471 			clear_opt(sbi->s_mount_opt, XATTR_USER);
1472 			break;
1473 #else
1474 		case Opt_user_xattr:
1475 		case Opt_nouser_xattr:
1476 			ext4_msg(sb, KERN_ERR, "(no)user_xattr options not supported");
1477 			break;
1478 #endif
1479 #ifdef CONFIG_EXT4_FS_POSIX_ACL
1480 		case Opt_acl:
1481 			set_opt(sbi->s_mount_opt, POSIX_ACL);
1482 			break;
1483 		case Opt_noacl:
1484 			clear_opt(sbi->s_mount_opt, POSIX_ACL);
1485 			break;
1486 #else
1487 		case Opt_acl:
1488 		case Opt_noacl:
1489 			ext4_msg(sb, KERN_ERR, "(no)acl options not supported");
1490 			break;
1491 #endif
1492 		case Opt_journal_update:
1493 			/* @@@ FIXME */
1494 			/* Eventually we will want to be able to create
1495 			   a journal file here.  For now, only allow the
1496 			   user to specify an existing inode to be the
1497 			   journal file. */
1498 			if (is_remount) {
1499 				ext4_msg(sb, KERN_ERR,
1500 					 "Cannot specify journal on remount");
1501 				return 0;
1502 			}
1503 			set_opt(sbi->s_mount_opt, UPDATE_JOURNAL);
1504 			break;
1505 		case Opt_journal_dev:
1506 			if (is_remount) {
1507 				ext4_msg(sb, KERN_ERR,
1508 					"Cannot specify journal on remount");
1509 				return 0;
1510 			}
1511 			if (match_int(&args[0], &option))
1512 				return 0;
1513 			*journal_devnum = option;
1514 			break;
1515 		case Opt_journal_checksum:
1516 			set_opt(sbi->s_mount_opt, JOURNAL_CHECKSUM);
1517 			break;
1518 		case Opt_journal_async_commit:
1519 			set_opt(sbi->s_mount_opt, JOURNAL_ASYNC_COMMIT);
1520 			set_opt(sbi->s_mount_opt, JOURNAL_CHECKSUM);
1521 			break;
1522 		case Opt_noload:
1523 			set_opt(sbi->s_mount_opt, NOLOAD);
1524 			break;
1525 		case Opt_commit:
1526 			if (match_int(&args[0], &option))
1527 				return 0;
1528 			if (option < 0)
1529 				return 0;
1530 			if (option == 0)
1531 				option = JBD2_DEFAULT_MAX_COMMIT_AGE;
1532 			sbi->s_commit_interval = HZ * option;
1533 			break;
1534 		case Opt_max_batch_time:
1535 			if (match_int(&args[0], &option))
1536 				return 0;
1537 			if (option < 0)
1538 				return 0;
1539 			if (option == 0)
1540 				option = EXT4_DEF_MAX_BATCH_TIME;
1541 			sbi->s_max_batch_time = option;
1542 			break;
1543 		case Opt_min_batch_time:
1544 			if (match_int(&args[0], &option))
1545 				return 0;
1546 			if (option < 0)
1547 				return 0;
1548 			sbi->s_min_batch_time = option;
1549 			break;
1550 		case Opt_data_journal:
1551 			data_opt = EXT4_MOUNT_JOURNAL_DATA;
1552 			goto datacheck;
1553 		case Opt_data_ordered:
1554 			data_opt = EXT4_MOUNT_ORDERED_DATA;
1555 			goto datacheck;
1556 		case Opt_data_writeback:
1557 			data_opt = EXT4_MOUNT_WRITEBACK_DATA;
1558 		datacheck:
1559 			if (is_remount) {
1560 				if (test_opt(sb, DATA_FLAGS) != data_opt) {
1561 					ext4_msg(sb, KERN_ERR,
1562 						"Cannot change data mode on remount");
1563 					return 0;
1564 				}
1565 			} else {
1566 				clear_opt(sbi->s_mount_opt, DATA_FLAGS);
1567 				sbi->s_mount_opt |= data_opt;
1568 			}
1569 			break;
1570 		case Opt_data_err_abort:
1571 			set_opt(sbi->s_mount_opt, DATA_ERR_ABORT);
1572 			break;
1573 		case Opt_data_err_ignore:
1574 			clear_opt(sbi->s_mount_opt, DATA_ERR_ABORT);
1575 			break;
1576 #ifdef CONFIG_QUOTA
1577 		case Opt_usrjquota:
1578 			if (!set_qf_name(sb, USRQUOTA, &args[0]))
1579 				return 0;
1580 			break;
1581 		case Opt_grpjquota:
1582 			if (!set_qf_name(sb, GRPQUOTA, &args[0]))
1583 				return 0;
1584 			break;
1585 		case Opt_offusrjquota:
1586 			if (!clear_qf_name(sb, USRQUOTA))
1587 				return 0;
1588 			break;
1589 		case Opt_offgrpjquota:
1590 			if (!clear_qf_name(sb, GRPQUOTA))
1591 				return 0;
1592 			break;
1593 
1594 		case Opt_jqfmt_vfsold:
1595 			qfmt = QFMT_VFS_OLD;
1596 			goto set_qf_format;
1597 		case Opt_jqfmt_vfsv0:
1598 			qfmt = QFMT_VFS_V0;
1599 			goto set_qf_format;
1600 		case Opt_jqfmt_vfsv1:
1601 			qfmt = QFMT_VFS_V1;
1602 set_qf_format:
1603 			if (sb_any_quota_loaded(sb) &&
1604 			    sbi->s_jquota_fmt != qfmt) {
1605 				ext4_msg(sb, KERN_ERR, "Cannot change "
1606 					"journaled quota options when "
1607 					"quota turned on");
1608 				return 0;
1609 			}
1610 			sbi->s_jquota_fmt = qfmt;
1611 			break;
1612 		case Opt_quota:
1613 		case Opt_usrquota:
1614 			set_opt(sbi->s_mount_opt, QUOTA);
1615 			set_opt(sbi->s_mount_opt, USRQUOTA);
1616 			break;
1617 		case Opt_grpquota:
1618 			set_opt(sbi->s_mount_opt, QUOTA);
1619 			set_opt(sbi->s_mount_opt, GRPQUOTA);
1620 			break;
1621 		case Opt_noquota:
1622 			if (sb_any_quota_loaded(sb)) {
1623 				ext4_msg(sb, KERN_ERR, "Cannot change quota "
1624 					"options when quota turned on");
1625 				return 0;
1626 			}
1627 			clear_opt(sbi->s_mount_opt, QUOTA);
1628 			clear_opt(sbi->s_mount_opt, USRQUOTA);
1629 			clear_opt(sbi->s_mount_opt, GRPQUOTA);
1630 			break;
1631 #else
1632 		case Opt_quota:
1633 		case Opt_usrquota:
1634 		case Opt_grpquota:
1635 			ext4_msg(sb, KERN_ERR,
1636 				"quota options not supported");
1637 			break;
1638 		case Opt_usrjquota:
1639 		case Opt_grpjquota:
1640 		case Opt_offusrjquota:
1641 		case Opt_offgrpjquota:
1642 		case Opt_jqfmt_vfsold:
1643 		case Opt_jqfmt_vfsv0:
1644 		case Opt_jqfmt_vfsv1:
1645 			ext4_msg(sb, KERN_ERR,
1646 				"journaled quota options not supported");
1647 			break;
1648 		case Opt_noquota:
1649 			break;
1650 #endif
1651 		case Opt_abort:
1652 			sbi->s_mount_flags |= EXT4_MF_FS_ABORTED;
1653 			break;
1654 		case Opt_nobarrier:
1655 			clear_opt(sbi->s_mount_opt, BARRIER);
1656 			break;
1657 		case Opt_barrier:
1658 			if (args[0].from) {
1659 				if (match_int(&args[0], &option))
1660 					return 0;
1661 			} else
1662 				option = 1;	/* No argument, default to 1 */
1663 			if (option)
1664 				set_opt(sbi->s_mount_opt, BARRIER);
1665 			else
1666 				clear_opt(sbi->s_mount_opt, BARRIER);
1667 			break;
1668 		case Opt_ignore:
1669 			break;
1670 		case Opt_resize:
1671 			if (!is_remount) {
1672 				ext4_msg(sb, KERN_ERR,
1673 					"resize option only available "
1674 					"for remount");
1675 				return 0;
1676 			}
1677 			if (match_int(&args[0], &option) != 0)
1678 				return 0;
1679 			*n_blocks_count = option;
1680 			break;
1681 		case Opt_nobh:
1682 			ext4_msg(sb, KERN_WARNING,
1683 				 "Ignoring deprecated nobh option");
1684 			break;
1685 		case Opt_bh:
1686 			ext4_msg(sb, KERN_WARNING,
1687 				 "Ignoring deprecated bh option");
1688 			break;
1689 		case Opt_i_version:
1690 			set_opt(sbi->s_mount_opt, I_VERSION);
1691 			sb->s_flags |= MS_I_VERSION;
1692 			break;
1693 		case Opt_nodelalloc:
1694 			clear_opt(sbi->s_mount_opt, DELALLOC);
1695 			break;
1696 		case Opt_stripe:
1697 			if (match_int(&args[0], &option))
1698 				return 0;
1699 			if (option < 0)
1700 				return 0;
1701 			sbi->s_stripe = option;
1702 			break;
1703 		case Opt_delalloc:
1704 			set_opt(sbi->s_mount_opt, DELALLOC);
1705 			break;
1706 		case Opt_block_validity:
1707 			set_opt(sbi->s_mount_opt, BLOCK_VALIDITY);
1708 			break;
1709 		case Opt_noblock_validity:
1710 			clear_opt(sbi->s_mount_opt, BLOCK_VALIDITY);
1711 			break;
1712 		case Opt_inode_readahead_blks:
1713 			if (match_int(&args[0], &option))
1714 				return 0;
1715 			if (option < 0 || option > (1 << 30))
1716 				return 0;
1717 			if (!is_power_of_2(option)) {
1718 				ext4_msg(sb, KERN_ERR,
1719 					 "EXT4-fs: inode_readahead_blks"
1720 					 " must be a power of 2");
1721 				return 0;
1722 			}
1723 			sbi->s_inode_readahead_blks = option;
1724 			break;
1725 		case Opt_journal_ioprio:
1726 			if (match_int(&args[0], &option))
1727 				return 0;
1728 			if (option < 0 || option > 7)
1729 				break;
1730 			*journal_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE,
1731 							    option);
1732 			break;
1733 		case Opt_noauto_da_alloc:
1734 			set_opt(sbi->s_mount_opt,NO_AUTO_DA_ALLOC);
1735 			break;
1736 		case Opt_auto_da_alloc:
1737 			if (args[0].from) {
1738 				if (match_int(&args[0], &option))
1739 					return 0;
1740 			} else
1741 				option = 1;	/* No argument, default to 1 */
1742 			if (option)
1743 				clear_opt(sbi->s_mount_opt, NO_AUTO_DA_ALLOC);
1744 			else
1745 				set_opt(sbi->s_mount_opt,NO_AUTO_DA_ALLOC);
1746 			break;
1747 		case Opt_discard:
1748 			set_opt(sbi->s_mount_opt, DISCARD);
1749 			break;
1750 		case Opt_nodiscard:
1751 			clear_opt(sbi->s_mount_opt, DISCARD);
1752 			break;
1753 		case Opt_dioread_nolock:
1754 			set_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
1755 			break;
1756 		case Opt_dioread_lock:
1757 			clear_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
1758 			break;
1759 		default:
1760 			ext4_msg(sb, KERN_ERR,
1761 			       "Unrecognized mount option \"%s\" "
1762 			       "or missing value", p);
1763 			return 0;
1764 		}
1765 	}
1766 #ifdef CONFIG_QUOTA
1767 	if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
1768 		if (test_opt(sb, USRQUOTA) && sbi->s_qf_names[USRQUOTA])
1769 			clear_opt(sbi->s_mount_opt, USRQUOTA);
1770 
1771 		if (test_opt(sb, GRPQUOTA) && sbi->s_qf_names[GRPQUOTA])
1772 			clear_opt(sbi->s_mount_opt, GRPQUOTA);
1773 
1774 		if (test_opt(sb, GRPQUOTA) || test_opt(sb, USRQUOTA)) {
1775 			ext4_msg(sb, KERN_ERR, "old and new quota "
1776 					"format mixing");
1777 			return 0;
1778 		}
1779 
1780 		if (!sbi->s_jquota_fmt) {
1781 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1782 					"not specified");
1783 			return 0;
1784 		}
1785 	} else {
1786 		if (sbi->s_jquota_fmt) {
1787 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1788 					"specified with no journaling "
1789 					"enabled");
1790 			return 0;
1791 		}
1792 	}
1793 #endif
1794 	return 1;
1795 }
1796 
1797 static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
1798 			    int read_only)
1799 {
1800 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1801 	int res = 0;
1802 
1803 	if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
1804 		ext4_msg(sb, KERN_ERR, "revision level too high, "
1805 			 "forcing read-only mode");
1806 		res = MS_RDONLY;
1807 	}
1808 	if (read_only)
1809 		return res;
1810 	if (!(sbi->s_mount_state & EXT4_VALID_FS))
1811 		ext4_msg(sb, KERN_WARNING, "warning: mounting unchecked fs, "
1812 			 "running e2fsck is recommended");
1813 	else if ((sbi->s_mount_state & EXT4_ERROR_FS))
1814 		ext4_msg(sb, KERN_WARNING,
1815 			 "warning: mounting fs with errors, "
1816 			 "running e2fsck is recommended");
1817 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
1818 		 le16_to_cpu(es->s_mnt_count) >=
1819 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
1820 		ext4_msg(sb, KERN_WARNING,
1821 			 "warning: maximal mount count reached, "
1822 			 "running e2fsck is recommended");
1823 	else if (le32_to_cpu(es->s_checkinterval) &&
1824 		(le32_to_cpu(es->s_lastcheck) +
1825 			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
1826 		ext4_msg(sb, KERN_WARNING,
1827 			 "warning: checktime reached, "
1828 			 "running e2fsck is recommended");
1829 	if (!sbi->s_journal)
1830 		es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1831 	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
1832 		es->s_max_mnt_count = cpu_to_le16(EXT4_DFL_MAX_MNT_COUNT);
1833 	le16_add_cpu(&es->s_mnt_count, 1);
1834 	es->s_mtime = cpu_to_le32(get_seconds());
1835 	ext4_update_dynamic_rev(sb);
1836 	if (sbi->s_journal)
1837 		EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
1838 
1839 	ext4_commit_super(sb, 1);
1840 	if (test_opt(sb, DEBUG))
1841 		printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, "
1842 				"bpg=%lu, ipg=%lu, mo=%04x]\n",
1843 			sb->s_blocksize,
1844 			sbi->s_groups_count,
1845 			EXT4_BLOCKS_PER_GROUP(sb),
1846 			EXT4_INODES_PER_GROUP(sb),
1847 			sbi->s_mount_opt);
1848 
1849 	return res;
1850 }
1851 
1852 static int ext4_fill_flex_info(struct super_block *sb)
1853 {
1854 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1855 	struct ext4_group_desc *gdp = NULL;
1856 	ext4_group_t flex_group_count;
1857 	ext4_group_t flex_group;
1858 	int groups_per_flex = 0;
1859 	size_t size;
1860 	int i;
1861 
1862 	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
1863 	groups_per_flex = 1 << sbi->s_log_groups_per_flex;
1864 
1865 	if (groups_per_flex < 2) {
1866 		sbi->s_log_groups_per_flex = 0;
1867 		return 1;
1868 	}
1869 
1870 	/* We allocate both existing and potentially added groups */
1871 	flex_group_count = ((sbi->s_groups_count + groups_per_flex - 1) +
1872 			((le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) + 1) <<
1873 			      EXT4_DESC_PER_BLOCK_BITS(sb))) / groups_per_flex;
1874 	size = flex_group_count * sizeof(struct flex_groups);
1875 	sbi->s_flex_groups = kzalloc(size, GFP_KERNEL);
1876 	if (sbi->s_flex_groups == NULL) {
1877 		sbi->s_flex_groups = vmalloc(size);
1878 		if (sbi->s_flex_groups)
1879 			memset(sbi->s_flex_groups, 0, size);
1880 	}
1881 	if (sbi->s_flex_groups == NULL) {
1882 		ext4_msg(sb, KERN_ERR, "not enough memory for "
1883 				"%u flex groups", flex_group_count);
1884 		goto failed;
1885 	}
1886 
1887 	for (i = 0; i < sbi->s_groups_count; i++) {
1888 		gdp = ext4_get_group_desc(sb, i, NULL);
1889 
1890 		flex_group = ext4_flex_group(sbi, i);
1891 		atomic_add(ext4_free_inodes_count(sb, gdp),
1892 			   &sbi->s_flex_groups[flex_group].free_inodes);
1893 		atomic_add(ext4_free_blks_count(sb, gdp),
1894 			   &sbi->s_flex_groups[flex_group].free_blocks);
1895 		atomic_add(ext4_used_dirs_count(sb, gdp),
1896 			   &sbi->s_flex_groups[flex_group].used_dirs);
1897 	}
1898 
1899 	return 1;
1900 failed:
1901 	return 0;
1902 }
1903 
1904 __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
1905 			    struct ext4_group_desc *gdp)
1906 {
1907 	__u16 crc = 0;
1908 
1909 	if (sbi->s_es->s_feature_ro_compat &
1910 	    cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
1911 		int offset = offsetof(struct ext4_group_desc, bg_checksum);
1912 		__le32 le_group = cpu_to_le32(block_group);
1913 
1914 		crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
1915 		crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
1916 		crc = crc16(crc, (__u8 *)gdp, offset);
1917 		offset += sizeof(gdp->bg_checksum); /* skip checksum */
1918 		/* for checksum of struct ext4_group_desc do the rest...*/
1919 		if ((sbi->s_es->s_feature_incompat &
1920 		     cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) &&
1921 		    offset < le16_to_cpu(sbi->s_es->s_desc_size))
1922 			crc = crc16(crc, (__u8 *)gdp + offset,
1923 				    le16_to_cpu(sbi->s_es->s_desc_size) -
1924 					offset);
1925 	}
1926 
1927 	return cpu_to_le16(crc);
1928 }
1929 
1930 int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 block_group,
1931 				struct ext4_group_desc *gdp)
1932 {
1933 	if ((sbi->s_es->s_feature_ro_compat &
1934 	     cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) &&
1935 	    (gdp->bg_checksum != ext4_group_desc_csum(sbi, block_group, gdp)))
1936 		return 0;
1937 
1938 	return 1;
1939 }
1940 
1941 /* Called at mount-time, super-block is locked */
1942 static int ext4_check_descriptors(struct super_block *sb)
1943 {
1944 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1945 	ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
1946 	ext4_fsblk_t last_block;
1947 	ext4_fsblk_t block_bitmap;
1948 	ext4_fsblk_t inode_bitmap;
1949 	ext4_fsblk_t inode_table;
1950 	int flexbg_flag = 0;
1951 	ext4_group_t i;
1952 
1953 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
1954 		flexbg_flag = 1;
1955 
1956 	ext4_debug("Checking group descriptors");
1957 
1958 	for (i = 0; i < sbi->s_groups_count; i++) {
1959 		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1960 
1961 		if (i == sbi->s_groups_count - 1 || flexbg_flag)
1962 			last_block = ext4_blocks_count(sbi->s_es) - 1;
1963 		else
1964 			last_block = first_block +
1965 				(EXT4_BLOCKS_PER_GROUP(sb) - 1);
1966 
1967 		block_bitmap = ext4_block_bitmap(sb, gdp);
1968 		if (block_bitmap < first_block || block_bitmap > last_block) {
1969 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
1970 			       "Block bitmap for group %u not in group "
1971 			       "(block %llu)!", i, block_bitmap);
1972 			return 0;
1973 		}
1974 		inode_bitmap = ext4_inode_bitmap(sb, gdp);
1975 		if (inode_bitmap < first_block || inode_bitmap > last_block) {
1976 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
1977 			       "Inode bitmap for group %u not in group "
1978 			       "(block %llu)!", i, inode_bitmap);
1979 			return 0;
1980 		}
1981 		inode_table = ext4_inode_table(sb, gdp);
1982 		if (inode_table < first_block ||
1983 		    inode_table + sbi->s_itb_per_group - 1 > last_block) {
1984 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
1985 			       "Inode table for group %u not in group "
1986 			       "(block %llu)!", i, inode_table);
1987 			return 0;
1988 		}
1989 		ext4_lock_group(sb, i);
1990 		if (!ext4_group_desc_csum_verify(sbi, i, gdp)) {
1991 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
1992 				 "Checksum for group %u failed (%u!=%u)",
1993 				 i, le16_to_cpu(ext4_group_desc_csum(sbi, i,
1994 				     gdp)), le16_to_cpu(gdp->bg_checksum));
1995 			if (!(sb->s_flags & MS_RDONLY)) {
1996 				ext4_unlock_group(sb, i);
1997 				return 0;
1998 			}
1999 		}
2000 		ext4_unlock_group(sb, i);
2001 		if (!flexbg_flag)
2002 			first_block += EXT4_BLOCKS_PER_GROUP(sb);
2003 	}
2004 
2005 	ext4_free_blocks_count_set(sbi->s_es, ext4_count_free_blocks(sb));
2006 	sbi->s_es->s_free_inodes_count =cpu_to_le32(ext4_count_free_inodes(sb));
2007 	return 1;
2008 }
2009 
2010 /* ext4_orphan_cleanup() walks a singly-linked list of inodes (starting at
2011  * the superblock) which were deleted from all directories, but held open by
2012  * a process at the time of a crash.  We walk the list and try to delete these
2013  * inodes at recovery time (only with a read-write filesystem).
2014  *
2015  * In order to keep the orphan inode chain consistent during traversal (in
2016  * case of crash during recovery), we link each inode into the superblock
2017  * orphan list_head and handle it the same way as an inode deletion during
2018  * normal operation (which journals the operations for us).
2019  *
2020  * We only do an iget() and an iput() on each inode, which is very safe if we
2021  * accidentally point at an in-use or already deleted inode.  The worst that
2022  * can happen in this case is that we get a "bit already cleared" message from
2023  * ext4_free_inode().  The only reason we would point at a wrong inode is if
2024  * e2fsck was run on this filesystem, and it must have already done the orphan
2025  * inode cleanup for us, so we can safely abort without any further action.
2026  */
2027 static void ext4_orphan_cleanup(struct super_block *sb,
2028 				struct ext4_super_block *es)
2029 {
2030 	unsigned int s_flags = sb->s_flags;
2031 	int nr_orphans = 0, nr_truncates = 0;
2032 #ifdef CONFIG_QUOTA
2033 	int i;
2034 #endif
2035 	if (!es->s_last_orphan) {
2036 		jbd_debug(4, "no orphan inodes to clean up\n");
2037 		return;
2038 	}
2039 
2040 	if (bdev_read_only(sb->s_bdev)) {
2041 		ext4_msg(sb, KERN_ERR, "write access "
2042 			"unavailable, skipping orphan cleanup");
2043 		return;
2044 	}
2045 
2046 	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
2047 		if (es->s_last_orphan)
2048 			jbd_debug(1, "Errors on filesystem, "
2049 				  "clearing orphan list.\n");
2050 		es->s_last_orphan = 0;
2051 		jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
2052 		return;
2053 	}
2054 
2055 	if (s_flags & MS_RDONLY) {
2056 		ext4_msg(sb, KERN_INFO, "orphan cleanup on readonly fs");
2057 		sb->s_flags &= ~MS_RDONLY;
2058 	}
2059 #ifdef CONFIG_QUOTA
2060 	/* Needed for iput() to work correctly and not trash data */
2061 	sb->s_flags |= MS_ACTIVE;
2062 	/* Turn on quotas so that they are updated correctly */
2063 	for (i = 0; i < MAXQUOTAS; i++) {
2064 		if (EXT4_SB(sb)->s_qf_names[i]) {
2065 			int ret = ext4_quota_on_mount(sb, i);
2066 			if (ret < 0)
2067 				ext4_msg(sb, KERN_ERR,
2068 					"Cannot turn on journaled "
2069 					"quota: error %d", ret);
2070 		}
2071 	}
2072 #endif
2073 
2074 	while (es->s_last_orphan) {
2075 		struct inode *inode;
2076 
2077 		inode = ext4_orphan_get(sb, le32_to_cpu(es->s_last_orphan));
2078 		if (IS_ERR(inode)) {
2079 			es->s_last_orphan = 0;
2080 			break;
2081 		}
2082 
2083 		list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
2084 		dquot_initialize(inode);
2085 		if (inode->i_nlink) {
2086 			ext4_msg(sb, KERN_DEBUG,
2087 				"%s: truncating inode %lu to %lld bytes",
2088 				__func__, inode->i_ino, inode->i_size);
2089 			jbd_debug(2, "truncating inode %lu to %lld bytes\n",
2090 				  inode->i_ino, inode->i_size);
2091 			ext4_truncate(inode);
2092 			nr_truncates++;
2093 		} else {
2094 			ext4_msg(sb, KERN_DEBUG,
2095 				"%s: deleting unreferenced inode %lu",
2096 				__func__, inode->i_ino);
2097 			jbd_debug(2, "deleting unreferenced inode %lu\n",
2098 				  inode->i_ino);
2099 			nr_orphans++;
2100 		}
2101 		iput(inode);  /* The delete magic happens here! */
2102 	}
2103 
2104 #define PLURAL(x) (x), ((x) == 1) ? "" : "s"
2105 
2106 	if (nr_orphans)
2107 		ext4_msg(sb, KERN_INFO, "%d orphan inode%s deleted",
2108 		       PLURAL(nr_orphans));
2109 	if (nr_truncates)
2110 		ext4_msg(sb, KERN_INFO, "%d truncate%s cleaned up",
2111 		       PLURAL(nr_truncates));
2112 #ifdef CONFIG_QUOTA
2113 	/* Turn quotas off */
2114 	for (i = 0; i < MAXQUOTAS; i++) {
2115 		if (sb_dqopt(sb)->files[i])
2116 			dquot_quota_off(sb, i);
2117 	}
2118 #endif
2119 	sb->s_flags = s_flags; /* Restore MS_RDONLY status */
2120 }
2121 
2122 /*
2123  * Maximal extent format file size.
2124  * Resulting logical blkno at s_maxbytes must fit in our on-disk
2125  * extent format containers, within a sector_t, and within i_blocks
2126  * in the vfs.  ext4 inode has 48 bits of i_block in fsblock units,
2127  * so that won't be a limiting factor.
2128  *
2129  * Note, this does *not* consider any metadata overhead for vfs i_blocks.
2130  */
2131 static loff_t ext4_max_size(int blkbits, int has_huge_files)
2132 {
2133 	loff_t res;
2134 	loff_t upper_limit = MAX_LFS_FILESIZE;
2135 
2136 	/* small i_blocks in vfs inode? */
2137 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2138 		/*
2139 		 * CONFIG_LBDAF is not enabled implies the inode
2140 		 * i_block represent total blocks in 512 bytes
2141 		 * 32 == size of vfs inode i_blocks * 8
2142 		 */
2143 		upper_limit = (1LL << 32) - 1;
2144 
2145 		/* total blocks in file system block size */
2146 		upper_limit >>= (blkbits - 9);
2147 		upper_limit <<= blkbits;
2148 	}
2149 
2150 	/* 32-bit extent-start container, ee_block */
2151 	res = 1LL << 32;
2152 	res <<= blkbits;
2153 	res -= 1;
2154 
2155 	/* Sanity check against vm- & vfs- imposed limits */
2156 	if (res > upper_limit)
2157 		res = upper_limit;
2158 
2159 	return res;
2160 }
2161 
2162 /*
2163  * Maximal bitmap file size.  There is a direct, and {,double-,triple-}indirect
2164  * block limit, and also a limit of (2^48 - 1) 512-byte sectors in i_blocks.
2165  * We need to be 1 filesystem block less than the 2^48 sector limit.
2166  */
2167 static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
2168 {
2169 	loff_t res = EXT4_NDIR_BLOCKS;
2170 	int meta_blocks;
2171 	loff_t upper_limit;
2172 	/* This is calculated to be the largest file size for a dense, block
2173 	 * mapped file such that the file's total number of 512-byte sectors,
2174 	 * including data and all indirect blocks, does not exceed (2^48 - 1).
2175 	 *
2176 	 * __u32 i_blocks_lo and _u16 i_blocks_high represent the total
2177 	 * number of 512-byte sectors of the file.
2178 	 */
2179 
2180 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2181 		/*
2182 		 * !has_huge_files or CONFIG_LBDAF not enabled implies that
2183 		 * the inode i_block field represents total file blocks in
2184 		 * 2^32 512-byte sectors == size of vfs inode i_blocks * 8
2185 		 */
2186 		upper_limit = (1LL << 32) - 1;
2187 
2188 		/* total blocks in file system block size */
2189 		upper_limit >>= (bits - 9);
2190 
2191 	} else {
2192 		/*
2193 		 * We use 48 bit ext4_inode i_blocks
2194 		 * With EXT4_HUGE_FILE_FL set the i_blocks
2195 		 * represent total number of blocks in
2196 		 * file system block size
2197 		 */
2198 		upper_limit = (1LL << 48) - 1;
2199 
2200 	}
2201 
2202 	/* indirect blocks */
2203 	meta_blocks = 1;
2204 	/* double indirect blocks */
2205 	meta_blocks += 1 + (1LL << (bits-2));
2206 	/* tripple indirect blocks */
2207 	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
2208 
2209 	upper_limit -= meta_blocks;
2210 	upper_limit <<= bits;
2211 
2212 	res += 1LL << (bits-2);
2213 	res += 1LL << (2*(bits-2));
2214 	res += 1LL << (3*(bits-2));
2215 	res <<= bits;
2216 	if (res > upper_limit)
2217 		res = upper_limit;
2218 
2219 	if (res > MAX_LFS_FILESIZE)
2220 		res = MAX_LFS_FILESIZE;
2221 
2222 	return res;
2223 }
2224 
2225 static ext4_fsblk_t descriptor_loc(struct super_block *sb,
2226 				   ext4_fsblk_t logical_sb_block, int nr)
2227 {
2228 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2229 	ext4_group_t bg, first_meta_bg;
2230 	int has_super = 0;
2231 
2232 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
2233 
2234 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
2235 	    nr < first_meta_bg)
2236 		return logical_sb_block + nr + 1;
2237 	bg = sbi->s_desc_per_block * nr;
2238 	if (ext4_bg_has_super(sb, bg))
2239 		has_super = 1;
2240 
2241 	return (has_super + ext4_group_first_block_no(sb, bg));
2242 }
2243 
2244 /**
2245  * ext4_get_stripe_size: Get the stripe size.
2246  * @sbi: In memory super block info
2247  *
2248  * If we have specified it via mount option, then
2249  * use the mount option value. If the value specified at mount time is
2250  * greater than the blocks per group use the super block value.
2251  * If the super block value is greater than blocks per group return 0.
2252  * Allocator needs it be less than blocks per group.
2253  *
2254  */
2255 static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi)
2256 {
2257 	unsigned long stride = le16_to_cpu(sbi->s_es->s_raid_stride);
2258 	unsigned long stripe_width =
2259 			le32_to_cpu(sbi->s_es->s_raid_stripe_width);
2260 
2261 	if (sbi->s_stripe && sbi->s_stripe <= sbi->s_blocks_per_group)
2262 		return sbi->s_stripe;
2263 
2264 	if (stripe_width <= sbi->s_blocks_per_group)
2265 		return stripe_width;
2266 
2267 	if (stride <= sbi->s_blocks_per_group)
2268 		return stride;
2269 
2270 	return 0;
2271 }
2272 
2273 /* sysfs supprt */
2274 
2275 struct ext4_attr {
2276 	struct attribute attr;
2277 	ssize_t (*show)(struct ext4_attr *, struct ext4_sb_info *, char *);
2278 	ssize_t (*store)(struct ext4_attr *, struct ext4_sb_info *,
2279 			 const char *, size_t);
2280 	int offset;
2281 };
2282 
2283 static int parse_strtoul(const char *buf,
2284 		unsigned long max, unsigned long *value)
2285 {
2286 	char *endp;
2287 
2288 	*value = simple_strtoul(skip_spaces(buf), &endp, 0);
2289 	endp = skip_spaces(endp);
2290 	if (*endp || *value > max)
2291 		return -EINVAL;
2292 
2293 	return 0;
2294 }
2295 
2296 static ssize_t delayed_allocation_blocks_show(struct ext4_attr *a,
2297 					      struct ext4_sb_info *sbi,
2298 					      char *buf)
2299 {
2300 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2301 			(s64) percpu_counter_sum(&sbi->s_dirtyblocks_counter));
2302 }
2303 
2304 static ssize_t session_write_kbytes_show(struct ext4_attr *a,
2305 					 struct ext4_sb_info *sbi, char *buf)
2306 {
2307 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
2308 
2309 	if (!sb->s_bdev->bd_part)
2310 		return snprintf(buf, PAGE_SIZE, "0\n");
2311 	return snprintf(buf, PAGE_SIZE, "%lu\n",
2312 			(part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
2313 			 sbi->s_sectors_written_start) >> 1);
2314 }
2315 
2316 static ssize_t lifetime_write_kbytes_show(struct ext4_attr *a,
2317 					  struct ext4_sb_info *sbi, char *buf)
2318 {
2319 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
2320 
2321 	if (!sb->s_bdev->bd_part)
2322 		return snprintf(buf, PAGE_SIZE, "0\n");
2323 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2324 			(unsigned long long)(sbi->s_kbytes_written +
2325 			((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
2326 			  EXT4_SB(sb)->s_sectors_written_start) >> 1)));
2327 }
2328 
2329 static ssize_t inode_readahead_blks_store(struct ext4_attr *a,
2330 					  struct ext4_sb_info *sbi,
2331 					  const char *buf, size_t count)
2332 {
2333 	unsigned long t;
2334 
2335 	if (parse_strtoul(buf, 0x40000000, &t))
2336 		return -EINVAL;
2337 
2338 	if (!is_power_of_2(t))
2339 		return -EINVAL;
2340 
2341 	sbi->s_inode_readahead_blks = t;
2342 	return count;
2343 }
2344 
2345 static ssize_t sbi_ui_show(struct ext4_attr *a,
2346 			   struct ext4_sb_info *sbi, char *buf)
2347 {
2348 	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
2349 
2350 	return snprintf(buf, PAGE_SIZE, "%u\n", *ui);
2351 }
2352 
2353 static ssize_t sbi_ui_store(struct ext4_attr *a,
2354 			    struct ext4_sb_info *sbi,
2355 			    const char *buf, size_t count)
2356 {
2357 	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
2358 	unsigned long t;
2359 
2360 	if (parse_strtoul(buf, 0xffffffff, &t))
2361 		return -EINVAL;
2362 	*ui = t;
2363 	return count;
2364 }
2365 
2366 #define EXT4_ATTR_OFFSET(_name,_mode,_show,_store,_elname) \
2367 static struct ext4_attr ext4_attr_##_name = {			\
2368 	.attr = {.name = __stringify(_name), .mode = _mode },	\
2369 	.show	= _show,					\
2370 	.store	= _store,					\
2371 	.offset = offsetof(struct ext4_sb_info, _elname),	\
2372 }
2373 #define EXT4_ATTR(name, mode, show, store) \
2374 static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store)
2375 
2376 #define EXT4_RO_ATTR(name) EXT4_ATTR(name, 0444, name##_show, NULL)
2377 #define EXT4_RW_ATTR(name) EXT4_ATTR(name, 0644, name##_show, name##_store)
2378 #define EXT4_RW_ATTR_SBI_UI(name, elname)	\
2379 	EXT4_ATTR_OFFSET(name, 0644, sbi_ui_show, sbi_ui_store, elname)
2380 #define ATTR_LIST(name) &ext4_attr_##name.attr
2381 
2382 EXT4_RO_ATTR(delayed_allocation_blocks);
2383 EXT4_RO_ATTR(session_write_kbytes);
2384 EXT4_RO_ATTR(lifetime_write_kbytes);
2385 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, sbi_ui_show,
2386 		 inode_readahead_blks_store, s_inode_readahead_blks);
2387 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
2388 EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
2389 EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
2390 EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
2391 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
2392 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
2393 EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
2394 EXT4_RW_ATTR_SBI_UI(max_writeback_mb_bump, s_max_writeback_mb_bump);
2395 
2396 static struct attribute *ext4_attrs[] = {
2397 	ATTR_LIST(delayed_allocation_blocks),
2398 	ATTR_LIST(session_write_kbytes),
2399 	ATTR_LIST(lifetime_write_kbytes),
2400 	ATTR_LIST(inode_readahead_blks),
2401 	ATTR_LIST(inode_goal),
2402 	ATTR_LIST(mb_stats),
2403 	ATTR_LIST(mb_max_to_scan),
2404 	ATTR_LIST(mb_min_to_scan),
2405 	ATTR_LIST(mb_order2_req),
2406 	ATTR_LIST(mb_stream_req),
2407 	ATTR_LIST(mb_group_prealloc),
2408 	ATTR_LIST(max_writeback_mb_bump),
2409 	NULL,
2410 };
2411 
2412 static ssize_t ext4_attr_show(struct kobject *kobj,
2413 			      struct attribute *attr, char *buf)
2414 {
2415 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2416 						s_kobj);
2417 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
2418 
2419 	return a->show ? a->show(a, sbi, buf) : 0;
2420 }
2421 
2422 static ssize_t ext4_attr_store(struct kobject *kobj,
2423 			       struct attribute *attr,
2424 			       const char *buf, size_t len)
2425 {
2426 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2427 						s_kobj);
2428 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
2429 
2430 	return a->store ? a->store(a, sbi, buf, len) : 0;
2431 }
2432 
2433 static void ext4_sb_release(struct kobject *kobj)
2434 {
2435 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2436 						s_kobj);
2437 	complete(&sbi->s_kobj_unregister);
2438 }
2439 
2440 
2441 static const struct sysfs_ops ext4_attr_ops = {
2442 	.show	= ext4_attr_show,
2443 	.store	= ext4_attr_store,
2444 };
2445 
2446 static struct kobj_type ext4_ktype = {
2447 	.default_attrs	= ext4_attrs,
2448 	.sysfs_ops	= &ext4_attr_ops,
2449 	.release	= ext4_sb_release,
2450 };
2451 
2452 /*
2453  * Check whether this filesystem can be mounted based on
2454  * the features present and the RDONLY/RDWR mount requested.
2455  * Returns 1 if this filesystem can be mounted as requested,
2456  * 0 if it cannot be.
2457  */
2458 static int ext4_feature_set_ok(struct super_block *sb, int readonly)
2459 {
2460 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT4_FEATURE_INCOMPAT_SUPP)) {
2461 		ext4_msg(sb, KERN_ERR,
2462 			"Couldn't mount because of "
2463 			"unsupported optional features (%x)",
2464 			(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_incompat) &
2465 			~EXT4_FEATURE_INCOMPAT_SUPP));
2466 		return 0;
2467 	}
2468 
2469 	if (readonly)
2470 		return 1;
2471 
2472 	/* Check that feature set is OK for a read-write mount */
2473 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT4_FEATURE_RO_COMPAT_SUPP)) {
2474 		ext4_msg(sb, KERN_ERR, "couldn't mount RDWR because of "
2475 			 "unsupported optional features (%x)",
2476 			 (le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_ro_compat) &
2477 				~EXT4_FEATURE_RO_COMPAT_SUPP));
2478 		return 0;
2479 	}
2480 	/*
2481 	 * Large file size enabled file system can only be mounted
2482 	 * read-write on 32-bit systems if kernel is built with CONFIG_LBDAF
2483 	 */
2484 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
2485 		if (sizeof(blkcnt_t) < sizeof(u64)) {
2486 			ext4_msg(sb, KERN_ERR, "Filesystem with huge files "
2487 				 "cannot be mounted RDWR without "
2488 				 "CONFIG_LBDAF");
2489 			return 0;
2490 		}
2491 	}
2492 	return 1;
2493 }
2494 
2495 /*
2496  * This function is called once a day if we have errors logged
2497  * on the file system
2498  */
2499 static void print_daily_error_info(unsigned long arg)
2500 {
2501 	struct super_block *sb = (struct super_block *) arg;
2502 	struct ext4_sb_info *sbi;
2503 	struct ext4_super_block *es;
2504 
2505 	sbi = EXT4_SB(sb);
2506 	es = sbi->s_es;
2507 
2508 	if (es->s_error_count)
2509 		ext4_msg(sb, KERN_NOTICE, "error count: %u",
2510 			 le32_to_cpu(es->s_error_count));
2511 	if (es->s_first_error_time) {
2512 		printk(KERN_NOTICE "EXT4-fs (%s): initial error at %u: %.*s:%d",
2513 		       sb->s_id, le32_to_cpu(es->s_first_error_time),
2514 		       (int) sizeof(es->s_first_error_func),
2515 		       es->s_first_error_func,
2516 		       le32_to_cpu(es->s_first_error_line));
2517 		if (es->s_first_error_ino)
2518 			printk(": inode %u",
2519 			       le32_to_cpu(es->s_first_error_ino));
2520 		if (es->s_first_error_block)
2521 			printk(": block %llu", (unsigned long long)
2522 			       le64_to_cpu(es->s_first_error_block));
2523 		printk("\n");
2524 	}
2525 	if (es->s_last_error_time) {
2526 		printk(KERN_NOTICE "EXT4-fs (%s): last error at %u: %.*s:%d",
2527 		       sb->s_id, le32_to_cpu(es->s_last_error_time),
2528 		       (int) sizeof(es->s_last_error_func),
2529 		       es->s_last_error_func,
2530 		       le32_to_cpu(es->s_last_error_line));
2531 		if (es->s_last_error_ino)
2532 			printk(": inode %u",
2533 			       le32_to_cpu(es->s_last_error_ino));
2534 		if (es->s_last_error_block)
2535 			printk(": block %llu", (unsigned long long)
2536 			       le64_to_cpu(es->s_last_error_block));
2537 		printk("\n");
2538 	}
2539 	mod_timer(&sbi->s_err_report, jiffies + 24*60*60*HZ);  /* Once a day */
2540 }
2541 
2542 static int ext4_fill_super(struct super_block *sb, void *data, int silent)
2543 				__releases(kernel_lock)
2544 				__acquires(kernel_lock)
2545 {
2546 	char *orig_data = kstrdup(data, GFP_KERNEL);
2547 	struct buffer_head *bh;
2548 	struct ext4_super_block *es = NULL;
2549 	struct ext4_sb_info *sbi;
2550 	ext4_fsblk_t block;
2551 	ext4_fsblk_t sb_block = get_sb_block(&data);
2552 	ext4_fsblk_t logical_sb_block;
2553 	unsigned long offset = 0;
2554 	unsigned long journal_devnum = 0;
2555 	unsigned long def_mount_opts;
2556 	struct inode *root;
2557 	char *cp;
2558 	const char *descr;
2559 	int ret = -ENOMEM;
2560 	int blocksize;
2561 	unsigned int db_count;
2562 	unsigned int i;
2563 	int needs_recovery, has_huge_files;
2564 	__u64 blocks_count;
2565 	int err;
2566 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
2567 
2568 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
2569 	if (!sbi)
2570 		goto out_free_orig;
2571 
2572 	sbi->s_blockgroup_lock =
2573 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
2574 	if (!sbi->s_blockgroup_lock) {
2575 		kfree(sbi);
2576 		goto out_free_orig;
2577 	}
2578 	sb->s_fs_info = sbi;
2579 	sbi->s_mount_opt = 0;
2580 	sbi->s_resuid = EXT4_DEF_RESUID;
2581 	sbi->s_resgid = EXT4_DEF_RESGID;
2582 	sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
2583 	sbi->s_sb_block = sb_block;
2584 	if (sb->s_bdev->bd_part)
2585 		sbi->s_sectors_written_start =
2586 			part_stat_read(sb->s_bdev->bd_part, sectors[1]);
2587 
2588 	/* Cleanup superblock name */
2589 	for (cp = sb->s_id; (cp = strchr(cp, '/'));)
2590 		*cp = '!';
2591 
2592 	ret = -EINVAL;
2593 	blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
2594 	if (!blocksize) {
2595 		ext4_msg(sb, KERN_ERR, "unable to set blocksize");
2596 		goto out_fail;
2597 	}
2598 
2599 	/*
2600 	 * The ext4 superblock will not be buffer aligned for other than 1kB
2601 	 * block sizes.  We need to calculate the offset from buffer start.
2602 	 */
2603 	if (blocksize != EXT4_MIN_BLOCK_SIZE) {
2604 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
2605 		offset = do_div(logical_sb_block, blocksize);
2606 	} else {
2607 		logical_sb_block = sb_block;
2608 	}
2609 
2610 	if (!(bh = sb_bread(sb, logical_sb_block))) {
2611 		ext4_msg(sb, KERN_ERR, "unable to read superblock");
2612 		goto out_fail;
2613 	}
2614 	/*
2615 	 * Note: s_es must be initialized as soon as possible because
2616 	 *       some ext4 macro-instructions depend on its value
2617 	 */
2618 	es = (struct ext4_super_block *) (((char *)bh->b_data) + offset);
2619 	sbi->s_es = es;
2620 	sb->s_magic = le16_to_cpu(es->s_magic);
2621 	if (sb->s_magic != EXT4_SUPER_MAGIC)
2622 		goto cantfind_ext4;
2623 	sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
2624 
2625 	/* Set defaults before we parse the mount options */
2626 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
2627 	if (def_mount_opts & EXT4_DEFM_DEBUG)
2628 		set_opt(sbi->s_mount_opt, DEBUG);
2629 	if (def_mount_opts & EXT4_DEFM_BSDGROUPS) {
2630 		ext4_msg(sb, KERN_WARNING, deprecated_msg, "bsdgroups",
2631 			"2.6.38");
2632 		set_opt(sbi->s_mount_opt, GRPID);
2633 	}
2634 	if (def_mount_opts & EXT4_DEFM_UID16)
2635 		set_opt(sbi->s_mount_opt, NO_UID32);
2636 #ifdef CONFIG_EXT4_FS_XATTR
2637 	if (def_mount_opts & EXT4_DEFM_XATTR_USER)
2638 		set_opt(sbi->s_mount_opt, XATTR_USER);
2639 #endif
2640 #ifdef CONFIG_EXT4_FS_POSIX_ACL
2641 	if (def_mount_opts & EXT4_DEFM_ACL)
2642 		set_opt(sbi->s_mount_opt, POSIX_ACL);
2643 #endif
2644 	if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA)
2645 		set_opt(sbi->s_mount_opt, JOURNAL_DATA);
2646 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_ORDERED)
2647 		set_opt(sbi->s_mount_opt, ORDERED_DATA);
2648 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_WBACK)
2649 		set_opt(sbi->s_mount_opt, WRITEBACK_DATA);
2650 
2651 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_PANIC)
2652 		set_opt(sbi->s_mount_opt, ERRORS_PANIC);
2653 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_CONTINUE)
2654 		set_opt(sbi->s_mount_opt, ERRORS_CONT);
2655 	else
2656 		set_opt(sbi->s_mount_opt, ERRORS_RO);
2657 	if (def_mount_opts & EXT4_DEFM_BLOCK_VALIDITY)
2658 		set_opt(sbi->s_mount_opt, BLOCK_VALIDITY);
2659 	if (def_mount_opts & EXT4_DEFM_DISCARD)
2660 		set_opt(sbi->s_mount_opt, DISCARD);
2661 
2662 	sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
2663 	sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
2664 	sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ;
2665 	sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;
2666 	sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;
2667 
2668 	if ((def_mount_opts & EXT4_DEFM_NOBARRIER) == 0)
2669 		set_opt(sbi->s_mount_opt, BARRIER);
2670 
2671 	/*
2672 	 * enable delayed allocation by default
2673 	 * Use -o nodelalloc to turn it off
2674 	 */
2675 	if (!IS_EXT3_SB(sb) &&
2676 	    ((def_mount_opts & EXT4_DEFM_NODELALLOC) == 0))
2677 		set_opt(sbi->s_mount_opt, DELALLOC);
2678 
2679 	if (!parse_options((char *) sbi->s_es->s_mount_opts, sb,
2680 			   &journal_devnum, &journal_ioprio, NULL, 0)) {
2681 		ext4_msg(sb, KERN_WARNING,
2682 			 "failed to parse options in superblock: %s",
2683 			 sbi->s_es->s_mount_opts);
2684 	}
2685 	if (!parse_options((char *) data, sb, &journal_devnum,
2686 			   &journal_ioprio, NULL, 0))
2687 		goto failed_mount;
2688 
2689 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
2690 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
2691 
2692 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
2693 	    (EXT4_HAS_COMPAT_FEATURE(sb, ~0U) ||
2694 	     EXT4_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
2695 	     EXT4_HAS_INCOMPAT_FEATURE(sb, ~0U)))
2696 		ext4_msg(sb, KERN_WARNING,
2697 		       "feature flags set on rev 0 fs, "
2698 		       "running e2fsck is recommended");
2699 
2700 	/*
2701 	 * Check feature flags regardless of the revision level, since we
2702 	 * previously didn't change the revision level when setting the flags,
2703 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
2704 	 */
2705 	if (!ext4_feature_set_ok(sb, (sb->s_flags & MS_RDONLY)))
2706 		goto failed_mount;
2707 
2708 	blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
2709 
2710 	if (blocksize < EXT4_MIN_BLOCK_SIZE ||
2711 	    blocksize > EXT4_MAX_BLOCK_SIZE) {
2712 		ext4_msg(sb, KERN_ERR,
2713 		       "Unsupported filesystem blocksize %d", blocksize);
2714 		goto failed_mount;
2715 	}
2716 
2717 	if (sb->s_blocksize != blocksize) {
2718 		/* Validate the filesystem blocksize */
2719 		if (!sb_set_blocksize(sb, blocksize)) {
2720 			ext4_msg(sb, KERN_ERR, "bad block size %d",
2721 					blocksize);
2722 			goto failed_mount;
2723 		}
2724 
2725 		brelse(bh);
2726 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
2727 		offset = do_div(logical_sb_block, blocksize);
2728 		bh = sb_bread(sb, logical_sb_block);
2729 		if (!bh) {
2730 			ext4_msg(sb, KERN_ERR,
2731 			       "Can't read superblock on 2nd try");
2732 			goto failed_mount;
2733 		}
2734 		es = (struct ext4_super_block *)(((char *)bh->b_data) + offset);
2735 		sbi->s_es = es;
2736 		if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
2737 			ext4_msg(sb, KERN_ERR,
2738 			       "Magic mismatch, very weird!");
2739 			goto failed_mount;
2740 		}
2741 	}
2742 
2743 	has_huge_files = EXT4_HAS_RO_COMPAT_FEATURE(sb,
2744 				EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
2745 	sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits,
2746 						      has_huge_files);
2747 	sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits, has_huge_files);
2748 
2749 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) {
2750 		sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE;
2751 		sbi->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
2752 	} else {
2753 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
2754 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
2755 		if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
2756 		    (!is_power_of_2(sbi->s_inode_size)) ||
2757 		    (sbi->s_inode_size > blocksize)) {
2758 			ext4_msg(sb, KERN_ERR,
2759 			       "unsupported inode size: %d",
2760 			       sbi->s_inode_size);
2761 			goto failed_mount;
2762 		}
2763 		if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE)
2764 			sb->s_time_gran = 1 << (EXT4_EPOCH_BITS - 2);
2765 	}
2766 
2767 	sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
2768 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT)) {
2769 		if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT ||
2770 		    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
2771 		    !is_power_of_2(sbi->s_desc_size)) {
2772 			ext4_msg(sb, KERN_ERR,
2773 			       "unsupported descriptor size %lu",
2774 			       sbi->s_desc_size);
2775 			goto failed_mount;
2776 		}
2777 	} else
2778 		sbi->s_desc_size = EXT4_MIN_DESC_SIZE;
2779 
2780 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
2781 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
2782 	if (EXT4_INODE_SIZE(sb) == 0 || EXT4_INODES_PER_GROUP(sb) == 0)
2783 		goto cantfind_ext4;
2784 
2785 	sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
2786 	if (sbi->s_inodes_per_block == 0)
2787 		goto cantfind_ext4;
2788 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
2789 					sbi->s_inodes_per_block;
2790 	sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
2791 	sbi->s_sbh = bh;
2792 	sbi->s_mount_state = le16_to_cpu(es->s_state);
2793 	sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
2794 	sbi->s_desc_per_block_bits = ilog2(EXT4_DESC_PER_BLOCK(sb));
2795 
2796 	for (i = 0; i < 4; i++)
2797 		sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
2798 	sbi->s_def_hash_version = es->s_def_hash_version;
2799 	i = le32_to_cpu(es->s_flags);
2800 	if (i & EXT2_FLAGS_UNSIGNED_HASH)
2801 		sbi->s_hash_unsigned = 3;
2802 	else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) {
2803 #ifdef __CHAR_UNSIGNED__
2804 		es->s_flags |= cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH);
2805 		sbi->s_hash_unsigned = 3;
2806 #else
2807 		es->s_flags |= cpu_to_le32(EXT2_FLAGS_SIGNED_HASH);
2808 #endif
2809 		sb->s_dirt = 1;
2810 	}
2811 
2812 	if (sbi->s_blocks_per_group > blocksize * 8) {
2813 		ext4_msg(sb, KERN_ERR,
2814 		       "#blocks per group too big: %lu",
2815 		       sbi->s_blocks_per_group);
2816 		goto failed_mount;
2817 	}
2818 	if (sbi->s_inodes_per_group > blocksize * 8) {
2819 		ext4_msg(sb, KERN_ERR,
2820 		       "#inodes per group too big: %lu",
2821 		       sbi->s_inodes_per_group);
2822 		goto failed_mount;
2823 	}
2824 
2825 	/*
2826 	 * Test whether we have more sectors than will fit in sector_t,
2827 	 * and whether the max offset is addressable by the page cache.
2828 	 */
2829 	ret = generic_check_addressable(sb->s_blocksize_bits,
2830 					ext4_blocks_count(es));
2831 	if (ret) {
2832 		ext4_msg(sb, KERN_ERR, "filesystem"
2833 			 " too large to mount safely on this system");
2834 		if (sizeof(sector_t) < 8)
2835 			ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled");
2836 		goto failed_mount;
2837 	}
2838 
2839 	if (EXT4_BLOCKS_PER_GROUP(sb) == 0)
2840 		goto cantfind_ext4;
2841 
2842 	/* check blocks count against device size */
2843 	blocks_count = sb->s_bdev->bd_inode->i_size >> sb->s_blocksize_bits;
2844 	if (blocks_count && ext4_blocks_count(es) > blocks_count) {
2845 		ext4_msg(sb, KERN_WARNING, "bad geometry: block count %llu "
2846 		       "exceeds size of device (%llu blocks)",
2847 		       ext4_blocks_count(es), blocks_count);
2848 		goto failed_mount;
2849 	}
2850 
2851 	/*
2852 	 * It makes no sense for the first data block to be beyond the end
2853 	 * of the filesystem.
2854 	 */
2855 	if (le32_to_cpu(es->s_first_data_block) >= ext4_blocks_count(es)) {
2856                 ext4_msg(sb, KERN_WARNING, "bad geometry: first data"
2857 			 "block %u is beyond end of filesystem (%llu)",
2858 			 le32_to_cpu(es->s_first_data_block),
2859 			 ext4_blocks_count(es));
2860 		goto failed_mount;
2861 	}
2862 	blocks_count = (ext4_blocks_count(es) -
2863 			le32_to_cpu(es->s_first_data_block) +
2864 			EXT4_BLOCKS_PER_GROUP(sb) - 1);
2865 	do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
2866 	if (blocks_count > ((uint64_t)1<<32) - EXT4_DESC_PER_BLOCK(sb)) {
2867 		ext4_msg(sb, KERN_WARNING, "groups count too large: %u "
2868 		       "(block count %llu, first data block %u, "
2869 		       "blocks per group %lu)", sbi->s_groups_count,
2870 		       ext4_blocks_count(es),
2871 		       le32_to_cpu(es->s_first_data_block),
2872 		       EXT4_BLOCKS_PER_GROUP(sb));
2873 		goto failed_mount;
2874 	}
2875 	sbi->s_groups_count = blocks_count;
2876 	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
2877 			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
2878 	db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
2879 		   EXT4_DESC_PER_BLOCK(sb);
2880 	sbi->s_group_desc = kmalloc(db_count * sizeof(struct buffer_head *),
2881 				    GFP_KERNEL);
2882 	if (sbi->s_group_desc == NULL) {
2883 		ext4_msg(sb, KERN_ERR, "not enough memory");
2884 		goto failed_mount;
2885 	}
2886 
2887 #ifdef CONFIG_PROC_FS
2888 	if (ext4_proc_root)
2889 		sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
2890 #endif
2891 
2892 	bgl_lock_init(sbi->s_blockgroup_lock);
2893 
2894 	for (i = 0; i < db_count; i++) {
2895 		block = descriptor_loc(sb, logical_sb_block, i);
2896 		sbi->s_group_desc[i] = sb_bread(sb, block);
2897 		if (!sbi->s_group_desc[i]) {
2898 			ext4_msg(sb, KERN_ERR,
2899 			       "can't read group descriptor %d", i);
2900 			db_count = i;
2901 			goto failed_mount2;
2902 		}
2903 	}
2904 	if (!ext4_check_descriptors(sb)) {
2905 		ext4_msg(sb, KERN_ERR, "group descriptors corrupted!");
2906 		goto failed_mount2;
2907 	}
2908 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
2909 		if (!ext4_fill_flex_info(sb)) {
2910 			ext4_msg(sb, KERN_ERR,
2911 			       "unable to initialize "
2912 			       "flex_bg meta info!");
2913 			goto failed_mount2;
2914 		}
2915 
2916 	sbi->s_gdb_count = db_count;
2917 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
2918 	spin_lock_init(&sbi->s_next_gen_lock);
2919 
2920 	sbi->s_stripe = ext4_get_stripe_size(sbi);
2921 	sbi->s_max_writeback_mb_bump = 128;
2922 
2923 	/*
2924 	 * set up enough so that it can read an inode
2925 	 */
2926 	if (!test_opt(sb, NOLOAD) &&
2927 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL))
2928 		sb->s_op = &ext4_sops;
2929 	else
2930 		sb->s_op = &ext4_nojournal_sops;
2931 	sb->s_export_op = &ext4_export_ops;
2932 	sb->s_xattr = ext4_xattr_handlers;
2933 #ifdef CONFIG_QUOTA
2934 	sb->s_qcop = &ext4_qctl_operations;
2935 	sb->dq_op = &ext4_quota_operations;
2936 #endif
2937 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
2938 	mutex_init(&sbi->s_orphan_lock);
2939 	mutex_init(&sbi->s_resize_lock);
2940 
2941 	sb->s_root = NULL;
2942 
2943 	needs_recovery = (es->s_last_orphan != 0 ||
2944 			  EXT4_HAS_INCOMPAT_FEATURE(sb,
2945 				    EXT4_FEATURE_INCOMPAT_RECOVER));
2946 
2947 	/*
2948 	 * The first inode we look at is the journal inode.  Don't try
2949 	 * root first: it may be modified in the journal!
2950 	 */
2951 	if (!test_opt(sb, NOLOAD) &&
2952 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
2953 		if (ext4_load_journal(sb, es, journal_devnum))
2954 			goto failed_mount3;
2955 	} else if (test_opt(sb, NOLOAD) && !(sb->s_flags & MS_RDONLY) &&
2956 	      EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
2957 		ext4_msg(sb, KERN_ERR, "required journal recovery "
2958 		       "suppressed and not mounted read-only");
2959 		goto failed_mount_wq;
2960 	} else {
2961 		clear_opt(sbi->s_mount_opt, DATA_FLAGS);
2962 		set_opt(sbi->s_mount_opt, WRITEBACK_DATA);
2963 		sbi->s_journal = NULL;
2964 		needs_recovery = 0;
2965 		goto no_journal;
2966 	}
2967 
2968 	if (ext4_blocks_count(es) > 0xffffffffULL &&
2969 	    !jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
2970 				       JBD2_FEATURE_INCOMPAT_64BIT)) {
2971 		ext4_msg(sb, KERN_ERR, "Failed to set 64-bit journal feature");
2972 		goto failed_mount_wq;
2973 	}
2974 
2975 	if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
2976 		jbd2_journal_set_features(sbi->s_journal,
2977 				JBD2_FEATURE_COMPAT_CHECKSUM, 0,
2978 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
2979 	} else if (test_opt(sb, JOURNAL_CHECKSUM)) {
2980 		jbd2_journal_set_features(sbi->s_journal,
2981 				JBD2_FEATURE_COMPAT_CHECKSUM, 0, 0);
2982 		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
2983 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
2984 	} else {
2985 		jbd2_journal_clear_features(sbi->s_journal,
2986 				JBD2_FEATURE_COMPAT_CHECKSUM, 0,
2987 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
2988 	}
2989 
2990 	/* We have now updated the journal if required, so we can
2991 	 * validate the data journaling mode. */
2992 	switch (test_opt(sb, DATA_FLAGS)) {
2993 	case 0:
2994 		/* No mode set, assume a default based on the journal
2995 		 * capabilities: ORDERED_DATA if the journal can
2996 		 * cope, else JOURNAL_DATA
2997 		 */
2998 		if (jbd2_journal_check_available_features
2999 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE))
3000 			set_opt(sbi->s_mount_opt, ORDERED_DATA);
3001 		else
3002 			set_opt(sbi->s_mount_opt, JOURNAL_DATA);
3003 		break;
3004 
3005 	case EXT4_MOUNT_ORDERED_DATA:
3006 	case EXT4_MOUNT_WRITEBACK_DATA:
3007 		if (!jbd2_journal_check_available_features
3008 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
3009 			ext4_msg(sb, KERN_ERR, "Journal does not support "
3010 			       "requested data journaling mode");
3011 			goto failed_mount_wq;
3012 		}
3013 	default:
3014 		break;
3015 	}
3016 	set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
3017 
3018 no_journal:
3019 	err = percpu_counter_init(&sbi->s_freeblocks_counter,
3020 				  ext4_count_free_blocks(sb));
3021 	if (!err)
3022 		err = percpu_counter_init(&sbi->s_freeinodes_counter,
3023 					  ext4_count_free_inodes(sb));
3024 	if (!err)
3025 		err = percpu_counter_init(&sbi->s_dirs_counter,
3026 					  ext4_count_dirs(sb));
3027 	if (!err)
3028 		err = percpu_counter_init(&sbi->s_dirtyblocks_counter, 0);
3029 	if (err) {
3030 		ext4_msg(sb, KERN_ERR, "insufficient memory");
3031 		goto failed_mount_wq;
3032 	}
3033 
3034 	EXT4_SB(sb)->dio_unwritten_wq = create_workqueue("ext4-dio-unwritten");
3035 	if (!EXT4_SB(sb)->dio_unwritten_wq) {
3036 		printk(KERN_ERR "EXT4-fs: failed to create DIO workqueue\n");
3037 		goto failed_mount_wq;
3038 	}
3039 
3040 	/*
3041 	 * The jbd2_journal_load will have done any necessary log recovery,
3042 	 * so we can safely mount the rest of the filesystem now.
3043 	 */
3044 
3045 	root = ext4_iget(sb, EXT4_ROOT_INO);
3046 	if (IS_ERR(root)) {
3047 		ext4_msg(sb, KERN_ERR, "get root inode failed");
3048 		ret = PTR_ERR(root);
3049 		goto failed_mount4;
3050 	}
3051 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
3052 		iput(root);
3053 		ext4_msg(sb, KERN_ERR, "corrupt root inode, run e2fsck");
3054 		goto failed_mount4;
3055 	}
3056 	sb->s_root = d_alloc_root(root);
3057 	if (!sb->s_root) {
3058 		ext4_msg(sb, KERN_ERR, "get root dentry failed");
3059 		iput(root);
3060 		ret = -ENOMEM;
3061 		goto failed_mount4;
3062 	}
3063 
3064 	ext4_setup_super(sb, es, sb->s_flags & MS_RDONLY);
3065 
3066 	/* determine the minimum size of new large inodes, if present */
3067 	if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
3068 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
3069 						     EXT4_GOOD_OLD_INODE_SIZE;
3070 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3071 				       EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE)) {
3072 			if (sbi->s_want_extra_isize <
3073 			    le16_to_cpu(es->s_want_extra_isize))
3074 				sbi->s_want_extra_isize =
3075 					le16_to_cpu(es->s_want_extra_isize);
3076 			if (sbi->s_want_extra_isize <
3077 			    le16_to_cpu(es->s_min_extra_isize))
3078 				sbi->s_want_extra_isize =
3079 					le16_to_cpu(es->s_min_extra_isize);
3080 		}
3081 	}
3082 	/* Check if enough inode space is available */
3083 	if (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize >
3084 							sbi->s_inode_size) {
3085 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
3086 						       EXT4_GOOD_OLD_INODE_SIZE;
3087 		ext4_msg(sb, KERN_INFO, "required extra inode space not"
3088 			 "available");
3089 	}
3090 
3091 	if (test_opt(sb, DELALLOC) &&
3092 	    (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)) {
3093 		ext4_msg(sb, KERN_WARNING, "Ignoring delalloc option - "
3094 			 "requested data journaling mode");
3095 		clear_opt(sbi->s_mount_opt, DELALLOC);
3096 	}
3097 	if (test_opt(sb, DIOREAD_NOLOCK)) {
3098 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
3099 			ext4_msg(sb, KERN_WARNING, "Ignoring dioread_nolock "
3100 				"option - requested data journaling mode");
3101 			clear_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
3102 		}
3103 		if (sb->s_blocksize < PAGE_SIZE) {
3104 			ext4_msg(sb, KERN_WARNING, "Ignoring dioread_nolock "
3105 				"option - block size is too small");
3106 			clear_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
3107 		}
3108 	}
3109 
3110 	err = ext4_setup_system_zone(sb);
3111 	if (err) {
3112 		ext4_msg(sb, KERN_ERR, "failed to initialize system "
3113 			 "zone (%d)", err);
3114 		goto failed_mount4;
3115 	}
3116 
3117 	ext4_ext_init(sb);
3118 	err = ext4_mb_init(sb, needs_recovery);
3119 	if (err) {
3120 		ext4_msg(sb, KERN_ERR, "failed to initialize mballoc (%d)",
3121 			 err);
3122 		goto failed_mount4;
3123 	}
3124 
3125 	sbi->s_kobj.kset = ext4_kset;
3126 	init_completion(&sbi->s_kobj_unregister);
3127 	err = kobject_init_and_add(&sbi->s_kobj, &ext4_ktype, NULL,
3128 				   "%s", sb->s_id);
3129 	if (err) {
3130 		ext4_mb_release(sb);
3131 		ext4_ext_release(sb);
3132 		goto failed_mount4;
3133 	};
3134 
3135 	EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
3136 	ext4_orphan_cleanup(sb, es);
3137 	EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
3138 	if (needs_recovery) {
3139 		ext4_msg(sb, KERN_INFO, "recovery complete");
3140 		ext4_mark_recovery_complete(sb, es);
3141 	}
3142 	if (EXT4_SB(sb)->s_journal) {
3143 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
3144 			descr = " journalled data mode";
3145 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
3146 			descr = " ordered data mode";
3147 		else
3148 			descr = " writeback data mode";
3149 	} else
3150 		descr = "out journal";
3151 
3152 	ext4_msg(sb, KERN_INFO, "mounted filesystem with%s. "
3153 		 "Opts: %s%s%s", descr, sbi->s_es->s_mount_opts,
3154 		 *sbi->s_es->s_mount_opts ? "; " : "", orig_data);
3155 
3156 	init_timer(&sbi->s_err_report);
3157 	sbi->s_err_report.function = print_daily_error_info;
3158 	sbi->s_err_report.data = (unsigned long) sb;
3159 	if (es->s_error_count)
3160 		mod_timer(&sbi->s_err_report, jiffies + 300*HZ); /* 5 minutes */
3161 
3162 	kfree(orig_data);
3163 	return 0;
3164 
3165 cantfind_ext4:
3166 	if (!silent)
3167 		ext4_msg(sb, KERN_ERR, "VFS: Can't find ext4 filesystem");
3168 	goto failed_mount;
3169 
3170 failed_mount4:
3171 	ext4_msg(sb, KERN_ERR, "mount failed");
3172 	destroy_workqueue(EXT4_SB(sb)->dio_unwritten_wq);
3173 failed_mount_wq:
3174 	ext4_release_system_zone(sb);
3175 	if (sbi->s_journal) {
3176 		jbd2_journal_destroy(sbi->s_journal);
3177 		sbi->s_journal = NULL;
3178 	}
3179 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
3180 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
3181 	percpu_counter_destroy(&sbi->s_dirs_counter);
3182 	percpu_counter_destroy(&sbi->s_dirtyblocks_counter);
3183 failed_mount3:
3184 	if (sbi->s_flex_groups) {
3185 		if (is_vmalloc_addr(sbi->s_flex_groups))
3186 			vfree(sbi->s_flex_groups);
3187 		else
3188 			kfree(sbi->s_flex_groups);
3189 	}
3190 failed_mount2:
3191 	for (i = 0; i < db_count; i++)
3192 		brelse(sbi->s_group_desc[i]);
3193 	kfree(sbi->s_group_desc);
3194 failed_mount:
3195 	if (sbi->s_proc) {
3196 		remove_proc_entry(sb->s_id, ext4_proc_root);
3197 	}
3198 #ifdef CONFIG_QUOTA
3199 	for (i = 0; i < MAXQUOTAS; i++)
3200 		kfree(sbi->s_qf_names[i]);
3201 #endif
3202 	ext4_blkdev_remove(sbi);
3203 	brelse(bh);
3204 out_fail:
3205 	sb->s_fs_info = NULL;
3206 	kfree(sbi->s_blockgroup_lock);
3207 	kfree(sbi);
3208 out_free_orig:
3209 	kfree(orig_data);
3210 	return ret;
3211 }
3212 
3213 /*
3214  * Setup any per-fs journal parameters now.  We'll do this both on
3215  * initial mount, once the journal has been initialised but before we've
3216  * done any recovery; and again on any subsequent remount.
3217  */
3218 static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
3219 {
3220 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3221 
3222 	journal->j_commit_interval = sbi->s_commit_interval;
3223 	journal->j_min_batch_time = sbi->s_min_batch_time;
3224 	journal->j_max_batch_time = sbi->s_max_batch_time;
3225 
3226 	write_lock(&journal->j_state_lock);
3227 	if (test_opt(sb, BARRIER))
3228 		journal->j_flags |= JBD2_BARRIER;
3229 	else
3230 		journal->j_flags &= ~JBD2_BARRIER;
3231 	if (test_opt(sb, DATA_ERR_ABORT))
3232 		journal->j_flags |= JBD2_ABORT_ON_SYNCDATA_ERR;
3233 	else
3234 		journal->j_flags &= ~JBD2_ABORT_ON_SYNCDATA_ERR;
3235 	write_unlock(&journal->j_state_lock);
3236 }
3237 
3238 static journal_t *ext4_get_journal(struct super_block *sb,
3239 				   unsigned int journal_inum)
3240 {
3241 	struct inode *journal_inode;
3242 	journal_t *journal;
3243 
3244 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
3245 
3246 	/* First, test for the existence of a valid inode on disk.  Bad
3247 	 * things happen if we iget() an unused inode, as the subsequent
3248 	 * iput() will try to delete it. */
3249 
3250 	journal_inode = ext4_iget(sb, journal_inum);
3251 	if (IS_ERR(journal_inode)) {
3252 		ext4_msg(sb, KERN_ERR, "no journal found");
3253 		return NULL;
3254 	}
3255 	if (!journal_inode->i_nlink) {
3256 		make_bad_inode(journal_inode);
3257 		iput(journal_inode);
3258 		ext4_msg(sb, KERN_ERR, "journal inode is deleted");
3259 		return NULL;
3260 	}
3261 
3262 	jbd_debug(2, "Journal inode found at %p: %lld bytes\n",
3263 		  journal_inode, journal_inode->i_size);
3264 	if (!S_ISREG(journal_inode->i_mode)) {
3265 		ext4_msg(sb, KERN_ERR, "invalid journal inode");
3266 		iput(journal_inode);
3267 		return NULL;
3268 	}
3269 
3270 	journal = jbd2_journal_init_inode(journal_inode);
3271 	if (!journal) {
3272 		ext4_msg(sb, KERN_ERR, "Could not load journal inode");
3273 		iput(journal_inode);
3274 		return NULL;
3275 	}
3276 	journal->j_private = sb;
3277 	ext4_init_journal_params(sb, journal);
3278 	return journal;
3279 }
3280 
3281 static journal_t *ext4_get_dev_journal(struct super_block *sb,
3282 				       dev_t j_dev)
3283 {
3284 	struct buffer_head *bh;
3285 	journal_t *journal;
3286 	ext4_fsblk_t start;
3287 	ext4_fsblk_t len;
3288 	int hblock, blocksize;
3289 	ext4_fsblk_t sb_block;
3290 	unsigned long offset;
3291 	struct ext4_super_block *es;
3292 	struct block_device *bdev;
3293 
3294 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
3295 
3296 	bdev = ext4_blkdev_get(j_dev, sb);
3297 	if (bdev == NULL)
3298 		return NULL;
3299 
3300 	if (bd_claim(bdev, sb)) {
3301 		ext4_msg(sb, KERN_ERR,
3302 			"failed to claim external journal device");
3303 		blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
3304 		return NULL;
3305 	}
3306 
3307 	blocksize = sb->s_blocksize;
3308 	hblock = bdev_logical_block_size(bdev);
3309 	if (blocksize < hblock) {
3310 		ext4_msg(sb, KERN_ERR,
3311 			"blocksize too small for journal device");
3312 		goto out_bdev;
3313 	}
3314 
3315 	sb_block = EXT4_MIN_BLOCK_SIZE / blocksize;
3316 	offset = EXT4_MIN_BLOCK_SIZE % blocksize;
3317 	set_blocksize(bdev, blocksize);
3318 	if (!(bh = __bread(bdev, sb_block, blocksize))) {
3319 		ext4_msg(sb, KERN_ERR, "couldn't read superblock of "
3320 		       "external journal");
3321 		goto out_bdev;
3322 	}
3323 
3324 	es = (struct ext4_super_block *) (((char *)bh->b_data) + offset);
3325 	if ((le16_to_cpu(es->s_magic) != EXT4_SUPER_MAGIC) ||
3326 	    !(le32_to_cpu(es->s_feature_incompat) &
3327 	      EXT4_FEATURE_INCOMPAT_JOURNAL_DEV)) {
3328 		ext4_msg(sb, KERN_ERR, "external journal has "
3329 					"bad superblock");
3330 		brelse(bh);
3331 		goto out_bdev;
3332 	}
3333 
3334 	if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
3335 		ext4_msg(sb, KERN_ERR, "journal UUID does not match");
3336 		brelse(bh);
3337 		goto out_bdev;
3338 	}
3339 
3340 	len = ext4_blocks_count(es);
3341 	start = sb_block + 1;
3342 	brelse(bh);	/* we're done with the superblock */
3343 
3344 	journal = jbd2_journal_init_dev(bdev, sb->s_bdev,
3345 					start, len, blocksize);
3346 	if (!journal) {
3347 		ext4_msg(sb, KERN_ERR, "failed to create device journal");
3348 		goto out_bdev;
3349 	}
3350 	journal->j_private = sb;
3351 	ll_rw_block(READ, 1, &journal->j_sb_buffer);
3352 	wait_on_buffer(journal->j_sb_buffer);
3353 	if (!buffer_uptodate(journal->j_sb_buffer)) {
3354 		ext4_msg(sb, KERN_ERR, "I/O error on journal device");
3355 		goto out_journal;
3356 	}
3357 	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
3358 		ext4_msg(sb, KERN_ERR, "External journal has more than one "
3359 					"user (unsupported) - %d",
3360 			be32_to_cpu(journal->j_superblock->s_nr_users));
3361 		goto out_journal;
3362 	}
3363 	EXT4_SB(sb)->journal_bdev = bdev;
3364 	ext4_init_journal_params(sb, journal);
3365 	return journal;
3366 
3367 out_journal:
3368 	jbd2_journal_destroy(journal);
3369 out_bdev:
3370 	ext4_blkdev_put(bdev);
3371 	return NULL;
3372 }
3373 
3374 static int ext4_load_journal(struct super_block *sb,
3375 			     struct ext4_super_block *es,
3376 			     unsigned long journal_devnum)
3377 {
3378 	journal_t *journal;
3379 	unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
3380 	dev_t journal_dev;
3381 	int err = 0;
3382 	int really_read_only;
3383 
3384 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
3385 
3386 	if (journal_devnum &&
3387 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
3388 		ext4_msg(sb, KERN_INFO, "external journal device major/minor "
3389 			"numbers have changed");
3390 		journal_dev = new_decode_dev(journal_devnum);
3391 	} else
3392 		journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));
3393 
3394 	really_read_only = bdev_read_only(sb->s_bdev);
3395 
3396 	/*
3397 	 * Are we loading a blank journal or performing recovery after a
3398 	 * crash?  For recovery, we need to check in advance whether we
3399 	 * can get read-write access to the device.
3400 	 */
3401 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
3402 		if (sb->s_flags & MS_RDONLY) {
3403 			ext4_msg(sb, KERN_INFO, "INFO: recovery "
3404 					"required on readonly filesystem");
3405 			if (really_read_only) {
3406 				ext4_msg(sb, KERN_ERR, "write access "
3407 					"unavailable, cannot proceed");
3408 				return -EROFS;
3409 			}
3410 			ext4_msg(sb, KERN_INFO, "write access will "
3411 			       "be enabled during recovery");
3412 		}
3413 	}
3414 
3415 	if (journal_inum && journal_dev) {
3416 		ext4_msg(sb, KERN_ERR, "filesystem has both journal "
3417 		       "and inode journals!");
3418 		return -EINVAL;
3419 	}
3420 
3421 	if (journal_inum) {
3422 		if (!(journal = ext4_get_journal(sb, journal_inum)))
3423 			return -EINVAL;
3424 	} else {
3425 		if (!(journal = ext4_get_dev_journal(sb, journal_dev)))
3426 			return -EINVAL;
3427 	}
3428 
3429 	if (!(journal->j_flags & JBD2_BARRIER))
3430 		ext4_msg(sb, KERN_INFO, "barriers disabled");
3431 
3432 	if (!really_read_only && test_opt(sb, UPDATE_JOURNAL)) {
3433 		err = jbd2_journal_update_format(journal);
3434 		if (err)  {
3435 			ext4_msg(sb, KERN_ERR, "error updating journal");
3436 			jbd2_journal_destroy(journal);
3437 			return err;
3438 		}
3439 	}
3440 
3441 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER))
3442 		err = jbd2_journal_wipe(journal, !really_read_only);
3443 	if (!err) {
3444 		char *save = kmalloc(EXT4_S_ERR_LEN, GFP_KERNEL);
3445 		if (save)
3446 			memcpy(save, ((char *) es) +
3447 			       EXT4_S_ERR_START, EXT4_S_ERR_LEN);
3448 		err = jbd2_journal_load(journal);
3449 		if (save)
3450 			memcpy(((char *) es) + EXT4_S_ERR_START,
3451 			       save, EXT4_S_ERR_LEN);
3452 		kfree(save);
3453 	}
3454 
3455 	if (err) {
3456 		ext4_msg(sb, KERN_ERR, "error loading journal");
3457 		jbd2_journal_destroy(journal);
3458 		return err;
3459 	}
3460 
3461 	EXT4_SB(sb)->s_journal = journal;
3462 	ext4_clear_journal_err(sb, es);
3463 
3464 	if (journal_devnum &&
3465 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
3466 		es->s_journal_dev = cpu_to_le32(journal_devnum);
3467 
3468 		/* Make sure we flush the recovery flag to disk. */
3469 		ext4_commit_super(sb, 1);
3470 	}
3471 
3472 	return 0;
3473 }
3474 
3475 static int ext4_commit_super(struct super_block *sb, int sync)
3476 {
3477 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
3478 	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
3479 	int error = 0;
3480 
3481 	if (!sbh)
3482 		return error;
3483 	if (buffer_write_io_error(sbh)) {
3484 		/*
3485 		 * Oh, dear.  A previous attempt to write the
3486 		 * superblock failed.  This could happen because the
3487 		 * USB device was yanked out.  Or it could happen to
3488 		 * be a transient write error and maybe the block will
3489 		 * be remapped.  Nothing we can do but to retry the
3490 		 * write and hope for the best.
3491 		 */
3492 		ext4_msg(sb, KERN_ERR, "previous I/O error to "
3493 		       "superblock detected");
3494 		clear_buffer_write_io_error(sbh);
3495 		set_buffer_uptodate(sbh);
3496 	}
3497 	/*
3498 	 * If the file system is mounted read-only, don't update the
3499 	 * superblock write time.  This avoids updating the superblock
3500 	 * write time when we are mounting the root file system
3501 	 * read/only but we need to replay the journal; at that point,
3502 	 * for people who are east of GMT and who make their clock
3503 	 * tick in localtime for Windows bug-for-bug compatibility,
3504 	 * the clock is set in the future, and this will cause e2fsck
3505 	 * to complain and force a full file system check.
3506 	 */
3507 	if (!(sb->s_flags & MS_RDONLY))
3508 		es->s_wtime = cpu_to_le32(get_seconds());
3509 	if (sb->s_bdev->bd_part)
3510 		es->s_kbytes_written =
3511 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written +
3512 			    ((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
3513 			      EXT4_SB(sb)->s_sectors_written_start) >> 1));
3514 	else
3515 		es->s_kbytes_written =
3516 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written);
3517 	ext4_free_blocks_count_set(es, percpu_counter_sum_positive(
3518 					&EXT4_SB(sb)->s_freeblocks_counter));
3519 	es->s_free_inodes_count = cpu_to_le32(percpu_counter_sum_positive(
3520 					&EXT4_SB(sb)->s_freeinodes_counter));
3521 	sb->s_dirt = 0;
3522 	BUFFER_TRACE(sbh, "marking dirty");
3523 	mark_buffer_dirty(sbh);
3524 	if (sync) {
3525 		error = sync_dirty_buffer(sbh);
3526 		if (error)
3527 			return error;
3528 
3529 		error = buffer_write_io_error(sbh);
3530 		if (error) {
3531 			ext4_msg(sb, KERN_ERR, "I/O error while writing "
3532 			       "superblock");
3533 			clear_buffer_write_io_error(sbh);
3534 			set_buffer_uptodate(sbh);
3535 		}
3536 	}
3537 	return error;
3538 }
3539 
3540 /*
3541  * Have we just finished recovery?  If so, and if we are mounting (or
3542  * remounting) the filesystem readonly, then we will end up with a
3543  * consistent fs on disk.  Record that fact.
3544  */
3545 static void ext4_mark_recovery_complete(struct super_block *sb,
3546 					struct ext4_super_block *es)
3547 {
3548 	journal_t *journal = EXT4_SB(sb)->s_journal;
3549 
3550 	if (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
3551 		BUG_ON(journal != NULL);
3552 		return;
3553 	}
3554 	jbd2_journal_lock_updates(journal);
3555 	if (jbd2_journal_flush(journal) < 0)
3556 		goto out;
3557 
3558 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER) &&
3559 	    sb->s_flags & MS_RDONLY) {
3560 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
3561 		ext4_commit_super(sb, 1);
3562 	}
3563 
3564 out:
3565 	jbd2_journal_unlock_updates(journal);
3566 }
3567 
3568 /*
3569  * If we are mounting (or read-write remounting) a filesystem whose journal
3570  * has recorded an error from a previous lifetime, move that error to the
3571  * main filesystem now.
3572  */
3573 static void ext4_clear_journal_err(struct super_block *sb,
3574 				   struct ext4_super_block *es)
3575 {
3576 	journal_t *journal;
3577 	int j_errno;
3578 	const char *errstr;
3579 
3580 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
3581 
3582 	journal = EXT4_SB(sb)->s_journal;
3583 
3584 	/*
3585 	 * Now check for any error status which may have been recorded in the
3586 	 * journal by a prior ext4_error() or ext4_abort()
3587 	 */
3588 
3589 	j_errno = jbd2_journal_errno(journal);
3590 	if (j_errno) {
3591 		char nbuf[16];
3592 
3593 		errstr = ext4_decode_error(sb, j_errno, nbuf);
3594 		ext4_warning(sb, "Filesystem error recorded "
3595 			     "from previous mount: %s", errstr);
3596 		ext4_warning(sb, "Marking fs in need of filesystem check.");
3597 
3598 		EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
3599 		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
3600 		ext4_commit_super(sb, 1);
3601 
3602 		jbd2_journal_clear_err(journal);
3603 	}
3604 }
3605 
3606 /*
3607  * Force the running and committing transactions to commit,
3608  * and wait on the commit.
3609  */
3610 int ext4_force_commit(struct super_block *sb)
3611 {
3612 	journal_t *journal;
3613 	int ret = 0;
3614 
3615 	if (sb->s_flags & MS_RDONLY)
3616 		return 0;
3617 
3618 	journal = EXT4_SB(sb)->s_journal;
3619 	if (journal) {
3620 		vfs_check_frozen(sb, SB_FREEZE_TRANS);
3621 		ret = ext4_journal_force_commit(journal);
3622 	}
3623 
3624 	return ret;
3625 }
3626 
3627 static void ext4_write_super(struct super_block *sb)
3628 {
3629 	lock_super(sb);
3630 	ext4_commit_super(sb, 1);
3631 	unlock_super(sb);
3632 }
3633 
3634 static int ext4_sync_fs(struct super_block *sb, int wait)
3635 {
3636 	int ret = 0;
3637 	tid_t target;
3638 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3639 
3640 	trace_ext4_sync_fs(sb, wait);
3641 	flush_workqueue(sbi->dio_unwritten_wq);
3642 	if (jbd2_journal_start_commit(sbi->s_journal, &target)) {
3643 		if (wait)
3644 			jbd2_log_wait_commit(sbi->s_journal, target);
3645 	}
3646 	return ret;
3647 }
3648 
3649 /*
3650  * LVM calls this function before a (read-only) snapshot is created.  This
3651  * gives us a chance to flush the journal completely and mark the fs clean.
3652  */
3653 static int ext4_freeze(struct super_block *sb)
3654 {
3655 	int error = 0;
3656 	journal_t *journal;
3657 
3658 	if (sb->s_flags & MS_RDONLY)
3659 		return 0;
3660 
3661 	journal = EXT4_SB(sb)->s_journal;
3662 
3663 	/* Now we set up the journal barrier. */
3664 	jbd2_journal_lock_updates(journal);
3665 
3666 	/*
3667 	 * Don't clear the needs_recovery flag if we failed to flush
3668 	 * the journal.
3669 	 */
3670 	error = jbd2_journal_flush(journal);
3671 	if (error < 0)
3672 		goto out;
3673 
3674 	/* Journal blocked and flushed, clear needs_recovery flag. */
3675 	EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
3676 	error = ext4_commit_super(sb, 1);
3677 out:
3678 	/* we rely on s_frozen to stop further updates */
3679 	jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
3680 	return error;
3681 }
3682 
3683 /*
3684  * Called by LVM after the snapshot is done.  We need to reset the RECOVER
3685  * flag here, even though the filesystem is not technically dirty yet.
3686  */
3687 static int ext4_unfreeze(struct super_block *sb)
3688 {
3689 	if (sb->s_flags & MS_RDONLY)
3690 		return 0;
3691 
3692 	lock_super(sb);
3693 	/* Reset the needs_recovery flag before the fs is unlocked. */
3694 	EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
3695 	ext4_commit_super(sb, 1);
3696 	unlock_super(sb);
3697 	return 0;
3698 }
3699 
3700 static int ext4_remount(struct super_block *sb, int *flags, char *data)
3701 {
3702 	struct ext4_super_block *es;
3703 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3704 	ext4_fsblk_t n_blocks_count = 0;
3705 	unsigned long old_sb_flags;
3706 	struct ext4_mount_options old_opts;
3707 	int enable_quota = 0;
3708 	ext4_group_t g;
3709 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
3710 	int err;
3711 #ifdef CONFIG_QUOTA
3712 	int i;
3713 #endif
3714 	char *orig_data = kstrdup(data, GFP_KERNEL);
3715 
3716 	/* Store the original options */
3717 	lock_super(sb);
3718 	old_sb_flags = sb->s_flags;
3719 	old_opts.s_mount_opt = sbi->s_mount_opt;
3720 	old_opts.s_resuid = sbi->s_resuid;
3721 	old_opts.s_resgid = sbi->s_resgid;
3722 	old_opts.s_commit_interval = sbi->s_commit_interval;
3723 	old_opts.s_min_batch_time = sbi->s_min_batch_time;
3724 	old_opts.s_max_batch_time = sbi->s_max_batch_time;
3725 #ifdef CONFIG_QUOTA
3726 	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
3727 	for (i = 0; i < MAXQUOTAS; i++)
3728 		old_opts.s_qf_names[i] = sbi->s_qf_names[i];
3729 #endif
3730 	if (sbi->s_journal && sbi->s_journal->j_task->io_context)
3731 		journal_ioprio = sbi->s_journal->j_task->io_context->ioprio;
3732 
3733 	/*
3734 	 * Allow the "check" option to be passed as a remount option.
3735 	 */
3736 	if (!parse_options(data, sb, NULL, &journal_ioprio,
3737 			   &n_blocks_count, 1)) {
3738 		err = -EINVAL;
3739 		goto restore_opts;
3740 	}
3741 
3742 	if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
3743 		ext4_abort(sb, "Abort forced by user");
3744 
3745 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
3746 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
3747 
3748 	es = sbi->s_es;
3749 
3750 	if (sbi->s_journal) {
3751 		ext4_init_journal_params(sb, sbi->s_journal);
3752 		set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
3753 	}
3754 
3755 	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY) ||
3756 		n_blocks_count > ext4_blocks_count(es)) {
3757 		if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) {
3758 			err = -EROFS;
3759 			goto restore_opts;
3760 		}
3761 
3762 		if (*flags & MS_RDONLY) {
3763 			err = dquot_suspend(sb, -1);
3764 			if (err < 0)
3765 				goto restore_opts;
3766 
3767 			/*
3768 			 * First of all, the unconditional stuff we have to do
3769 			 * to disable replay of the journal when we next remount
3770 			 */
3771 			sb->s_flags |= MS_RDONLY;
3772 
3773 			/*
3774 			 * OK, test if we are remounting a valid rw partition
3775 			 * readonly, and if so set the rdonly flag and then
3776 			 * mark the partition as valid again.
3777 			 */
3778 			if (!(es->s_state & cpu_to_le16(EXT4_VALID_FS)) &&
3779 			    (sbi->s_mount_state & EXT4_VALID_FS))
3780 				es->s_state = cpu_to_le16(sbi->s_mount_state);
3781 
3782 			if (sbi->s_journal)
3783 				ext4_mark_recovery_complete(sb, es);
3784 		} else {
3785 			/* Make sure we can mount this feature set readwrite */
3786 			if (!ext4_feature_set_ok(sb, 0)) {
3787 				err = -EROFS;
3788 				goto restore_opts;
3789 			}
3790 			/*
3791 			 * Make sure the group descriptor checksums
3792 			 * are sane.  If they aren't, refuse to remount r/w.
3793 			 */
3794 			for (g = 0; g < sbi->s_groups_count; g++) {
3795 				struct ext4_group_desc *gdp =
3796 					ext4_get_group_desc(sb, g, NULL);
3797 
3798 				if (!ext4_group_desc_csum_verify(sbi, g, gdp)) {
3799 					ext4_msg(sb, KERN_ERR,
3800 	       "ext4_remount: Checksum for group %u failed (%u!=%u)",
3801 		g, le16_to_cpu(ext4_group_desc_csum(sbi, g, gdp)),
3802 					       le16_to_cpu(gdp->bg_checksum));
3803 					err = -EINVAL;
3804 					goto restore_opts;
3805 				}
3806 			}
3807 
3808 			/*
3809 			 * If we have an unprocessed orphan list hanging
3810 			 * around from a previously readonly bdev mount,
3811 			 * require a full umount/remount for now.
3812 			 */
3813 			if (es->s_last_orphan) {
3814 				ext4_msg(sb, KERN_WARNING, "Couldn't "
3815 				       "remount RDWR because of unprocessed "
3816 				       "orphan inode list.  Please "
3817 				       "umount/remount instead");
3818 				err = -EINVAL;
3819 				goto restore_opts;
3820 			}
3821 
3822 			/*
3823 			 * Mounting a RDONLY partition read-write, so reread
3824 			 * and store the current valid flag.  (It may have
3825 			 * been changed by e2fsck since we originally mounted
3826 			 * the partition.)
3827 			 */
3828 			if (sbi->s_journal)
3829 				ext4_clear_journal_err(sb, es);
3830 			sbi->s_mount_state = le16_to_cpu(es->s_state);
3831 			if ((err = ext4_group_extend(sb, es, n_blocks_count)))
3832 				goto restore_opts;
3833 			if (!ext4_setup_super(sb, es, 0))
3834 				sb->s_flags &= ~MS_RDONLY;
3835 			enable_quota = 1;
3836 		}
3837 	}
3838 	ext4_setup_system_zone(sb);
3839 	if (sbi->s_journal == NULL)
3840 		ext4_commit_super(sb, 1);
3841 
3842 #ifdef CONFIG_QUOTA
3843 	/* Release old quota file names */
3844 	for (i = 0; i < MAXQUOTAS; i++)
3845 		if (old_opts.s_qf_names[i] &&
3846 		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
3847 			kfree(old_opts.s_qf_names[i]);
3848 #endif
3849 	unlock_super(sb);
3850 	if (enable_quota)
3851 		dquot_resume(sb, -1);
3852 
3853 	ext4_msg(sb, KERN_INFO, "re-mounted. Opts: %s", orig_data);
3854 	kfree(orig_data);
3855 	return 0;
3856 
3857 restore_opts:
3858 	sb->s_flags = old_sb_flags;
3859 	sbi->s_mount_opt = old_opts.s_mount_opt;
3860 	sbi->s_resuid = old_opts.s_resuid;
3861 	sbi->s_resgid = old_opts.s_resgid;
3862 	sbi->s_commit_interval = old_opts.s_commit_interval;
3863 	sbi->s_min_batch_time = old_opts.s_min_batch_time;
3864 	sbi->s_max_batch_time = old_opts.s_max_batch_time;
3865 #ifdef CONFIG_QUOTA
3866 	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
3867 	for (i = 0; i < MAXQUOTAS; i++) {
3868 		if (sbi->s_qf_names[i] &&
3869 		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
3870 			kfree(sbi->s_qf_names[i]);
3871 		sbi->s_qf_names[i] = old_opts.s_qf_names[i];
3872 	}
3873 #endif
3874 	unlock_super(sb);
3875 	kfree(orig_data);
3876 	return err;
3877 }
3878 
3879 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
3880 {
3881 	struct super_block *sb = dentry->d_sb;
3882 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3883 	struct ext4_super_block *es = sbi->s_es;
3884 	u64 fsid;
3885 
3886 	if (test_opt(sb, MINIX_DF)) {
3887 		sbi->s_overhead_last = 0;
3888 	} else if (sbi->s_blocks_last != ext4_blocks_count(es)) {
3889 		ext4_group_t i, ngroups = ext4_get_groups_count(sb);
3890 		ext4_fsblk_t overhead = 0;
3891 
3892 		/*
3893 		 * Compute the overhead (FS structures).  This is constant
3894 		 * for a given filesystem unless the number of block groups
3895 		 * changes so we cache the previous value until it does.
3896 		 */
3897 
3898 		/*
3899 		 * All of the blocks before first_data_block are
3900 		 * overhead
3901 		 */
3902 		overhead = le32_to_cpu(es->s_first_data_block);
3903 
3904 		/*
3905 		 * Add the overhead attributed to the superblock and
3906 		 * block group descriptors.  If the sparse superblocks
3907 		 * feature is turned on, then not all groups have this.
3908 		 */
3909 		for (i = 0; i < ngroups; i++) {
3910 			overhead += ext4_bg_has_super(sb, i) +
3911 				ext4_bg_num_gdb(sb, i);
3912 			cond_resched();
3913 		}
3914 
3915 		/*
3916 		 * Every block group has an inode bitmap, a block
3917 		 * bitmap, and an inode table.
3918 		 */
3919 		overhead += ngroups * (2 + sbi->s_itb_per_group);
3920 		sbi->s_overhead_last = overhead;
3921 		smp_wmb();
3922 		sbi->s_blocks_last = ext4_blocks_count(es);
3923 	}
3924 
3925 	buf->f_type = EXT4_SUPER_MAGIC;
3926 	buf->f_bsize = sb->s_blocksize;
3927 	buf->f_blocks = ext4_blocks_count(es) - sbi->s_overhead_last;
3928 	buf->f_bfree = percpu_counter_sum_positive(&sbi->s_freeblocks_counter) -
3929 		       percpu_counter_sum_positive(&sbi->s_dirtyblocks_counter);
3930 	buf->f_bavail = buf->f_bfree - ext4_r_blocks_count(es);
3931 	if (buf->f_bfree < ext4_r_blocks_count(es))
3932 		buf->f_bavail = 0;
3933 	buf->f_files = le32_to_cpu(es->s_inodes_count);
3934 	buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter);
3935 	buf->f_namelen = EXT4_NAME_LEN;
3936 	fsid = le64_to_cpup((void *)es->s_uuid) ^
3937 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
3938 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
3939 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
3940 
3941 	return 0;
3942 }
3943 
3944 /* Helper function for writing quotas on sync - we need to start transaction
3945  * before quota file is locked for write. Otherwise the are possible deadlocks:
3946  * Process 1                         Process 2
3947  * ext4_create()                     quota_sync()
3948  *   jbd2_journal_start()                  write_dquot()
3949  *   dquot_initialize()                         down(dqio_mutex)
3950  *     down(dqio_mutex)                    jbd2_journal_start()
3951  *
3952  */
3953 
3954 #ifdef CONFIG_QUOTA
3955 
3956 static inline struct inode *dquot_to_inode(struct dquot *dquot)
3957 {
3958 	return sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
3959 }
3960 
3961 static int ext4_write_dquot(struct dquot *dquot)
3962 {
3963 	int ret, err;
3964 	handle_t *handle;
3965 	struct inode *inode;
3966 
3967 	inode = dquot_to_inode(dquot);
3968 	handle = ext4_journal_start(inode,
3969 				    EXT4_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
3970 	if (IS_ERR(handle))
3971 		return PTR_ERR(handle);
3972 	ret = dquot_commit(dquot);
3973 	err = ext4_journal_stop(handle);
3974 	if (!ret)
3975 		ret = err;
3976 	return ret;
3977 }
3978 
3979 static int ext4_acquire_dquot(struct dquot *dquot)
3980 {
3981 	int ret, err;
3982 	handle_t *handle;
3983 
3984 	handle = ext4_journal_start(dquot_to_inode(dquot),
3985 				    EXT4_QUOTA_INIT_BLOCKS(dquot->dq_sb));
3986 	if (IS_ERR(handle))
3987 		return PTR_ERR(handle);
3988 	ret = dquot_acquire(dquot);
3989 	err = ext4_journal_stop(handle);
3990 	if (!ret)
3991 		ret = err;
3992 	return ret;
3993 }
3994 
3995 static int ext4_release_dquot(struct dquot *dquot)
3996 {
3997 	int ret, err;
3998 	handle_t *handle;
3999 
4000 	handle = ext4_journal_start(dquot_to_inode(dquot),
4001 				    EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
4002 	if (IS_ERR(handle)) {
4003 		/* Release dquot anyway to avoid endless cycle in dqput() */
4004 		dquot_release(dquot);
4005 		return PTR_ERR(handle);
4006 	}
4007 	ret = dquot_release(dquot);
4008 	err = ext4_journal_stop(handle);
4009 	if (!ret)
4010 		ret = err;
4011 	return ret;
4012 }
4013 
4014 static int ext4_mark_dquot_dirty(struct dquot *dquot)
4015 {
4016 	/* Are we journaling quotas? */
4017 	if (EXT4_SB(dquot->dq_sb)->s_qf_names[USRQUOTA] ||
4018 	    EXT4_SB(dquot->dq_sb)->s_qf_names[GRPQUOTA]) {
4019 		dquot_mark_dquot_dirty(dquot);
4020 		return ext4_write_dquot(dquot);
4021 	} else {
4022 		return dquot_mark_dquot_dirty(dquot);
4023 	}
4024 }
4025 
4026 static int ext4_write_info(struct super_block *sb, int type)
4027 {
4028 	int ret, err;
4029 	handle_t *handle;
4030 
4031 	/* Data block + inode block */
4032 	handle = ext4_journal_start(sb->s_root->d_inode, 2);
4033 	if (IS_ERR(handle))
4034 		return PTR_ERR(handle);
4035 	ret = dquot_commit_info(sb, type);
4036 	err = ext4_journal_stop(handle);
4037 	if (!ret)
4038 		ret = err;
4039 	return ret;
4040 }
4041 
4042 /*
4043  * Turn on quotas during mount time - we need to find
4044  * the quota file and such...
4045  */
4046 static int ext4_quota_on_mount(struct super_block *sb, int type)
4047 {
4048 	return dquot_quota_on_mount(sb, EXT4_SB(sb)->s_qf_names[type],
4049 					EXT4_SB(sb)->s_jquota_fmt, type);
4050 }
4051 
4052 /*
4053  * Standard function to be called on quota_on
4054  */
4055 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
4056 			 char *name)
4057 {
4058 	int err;
4059 	struct path path;
4060 
4061 	if (!test_opt(sb, QUOTA))
4062 		return -EINVAL;
4063 
4064 	err = kern_path(name, LOOKUP_FOLLOW, &path);
4065 	if (err)
4066 		return err;
4067 
4068 	/* Quotafile not on the same filesystem? */
4069 	if (path.mnt->mnt_sb != sb) {
4070 		path_put(&path);
4071 		return -EXDEV;
4072 	}
4073 	/* Journaling quota? */
4074 	if (EXT4_SB(sb)->s_qf_names[type]) {
4075 		/* Quotafile not in fs root? */
4076 		if (path.dentry->d_parent != sb->s_root)
4077 			ext4_msg(sb, KERN_WARNING,
4078 				"Quota file not on filesystem root. "
4079 				"Journaled quota will not work");
4080 	}
4081 
4082 	/*
4083 	 * When we journal data on quota file, we have to flush journal to see
4084 	 * all updates to the file when we bypass pagecache...
4085 	 */
4086 	if (EXT4_SB(sb)->s_journal &&
4087 	    ext4_should_journal_data(path.dentry->d_inode)) {
4088 		/*
4089 		 * We don't need to lock updates but journal_flush() could
4090 		 * otherwise be livelocked...
4091 		 */
4092 		jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
4093 		err = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
4094 		jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
4095 		if (err) {
4096 			path_put(&path);
4097 			return err;
4098 		}
4099 	}
4100 
4101 	err = dquot_quota_on_path(sb, type, format_id, &path);
4102 	path_put(&path);
4103 	return err;
4104 }
4105 
4106 static int ext4_quota_off(struct super_block *sb, int type)
4107 {
4108 	/* Force all delayed allocation blocks to be allocated */
4109 	if (test_opt(sb, DELALLOC)) {
4110 		down_read(&sb->s_umount);
4111 		sync_filesystem(sb);
4112 		up_read(&sb->s_umount);
4113 	}
4114 
4115 	return dquot_quota_off(sb, type);
4116 }
4117 
4118 /* Read data from quotafile - avoid pagecache and such because we cannot afford
4119  * acquiring the locks... As quota files are never truncated and quota code
4120  * itself serializes the operations (and noone else should touch the files)
4121  * we don't have to be afraid of races */
4122 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
4123 			       size_t len, loff_t off)
4124 {
4125 	struct inode *inode = sb_dqopt(sb)->files[type];
4126 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
4127 	int err = 0;
4128 	int offset = off & (sb->s_blocksize - 1);
4129 	int tocopy;
4130 	size_t toread;
4131 	struct buffer_head *bh;
4132 	loff_t i_size = i_size_read(inode);
4133 
4134 	if (off > i_size)
4135 		return 0;
4136 	if (off+len > i_size)
4137 		len = i_size-off;
4138 	toread = len;
4139 	while (toread > 0) {
4140 		tocopy = sb->s_blocksize - offset < toread ?
4141 				sb->s_blocksize - offset : toread;
4142 		bh = ext4_bread(NULL, inode, blk, 0, &err);
4143 		if (err)
4144 			return err;
4145 		if (!bh)	/* A hole? */
4146 			memset(data, 0, tocopy);
4147 		else
4148 			memcpy(data, bh->b_data+offset, tocopy);
4149 		brelse(bh);
4150 		offset = 0;
4151 		toread -= tocopy;
4152 		data += tocopy;
4153 		blk++;
4154 	}
4155 	return len;
4156 }
4157 
4158 /* Write to quotafile (we know the transaction is already started and has
4159  * enough credits) */
4160 static ssize_t ext4_quota_write(struct super_block *sb, int type,
4161 				const char *data, size_t len, loff_t off)
4162 {
4163 	struct inode *inode = sb_dqopt(sb)->files[type];
4164 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
4165 	int err = 0;
4166 	int offset = off & (sb->s_blocksize - 1);
4167 	struct buffer_head *bh;
4168 	handle_t *handle = journal_current_handle();
4169 
4170 	if (EXT4_SB(sb)->s_journal && !handle) {
4171 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
4172 			" cancelled because transaction is not started",
4173 			(unsigned long long)off, (unsigned long long)len);
4174 		return -EIO;
4175 	}
4176 	/*
4177 	 * Since we account only one data block in transaction credits,
4178 	 * then it is impossible to cross a block boundary.
4179 	 */
4180 	if (sb->s_blocksize - offset < len) {
4181 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
4182 			" cancelled because not block aligned",
4183 			(unsigned long long)off, (unsigned long long)len);
4184 		return -EIO;
4185 	}
4186 
4187 	mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
4188 	bh = ext4_bread(handle, inode, blk, 1, &err);
4189 	if (!bh)
4190 		goto out;
4191 	err = ext4_journal_get_write_access(handle, bh);
4192 	if (err) {
4193 		brelse(bh);
4194 		goto out;
4195 	}
4196 	lock_buffer(bh);
4197 	memcpy(bh->b_data+offset, data, len);
4198 	flush_dcache_page(bh->b_page);
4199 	unlock_buffer(bh);
4200 	err = ext4_handle_dirty_metadata(handle, NULL, bh);
4201 	brelse(bh);
4202 out:
4203 	if (err) {
4204 		mutex_unlock(&inode->i_mutex);
4205 		return err;
4206 	}
4207 	if (inode->i_size < off + len) {
4208 		i_size_write(inode, off + len);
4209 		EXT4_I(inode)->i_disksize = inode->i_size;
4210 	}
4211 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
4212 	ext4_mark_inode_dirty(handle, inode);
4213 	mutex_unlock(&inode->i_mutex);
4214 	return len;
4215 }
4216 
4217 #endif
4218 
4219 static int ext4_get_sb(struct file_system_type *fs_type, int flags,
4220 		       const char *dev_name, void *data, struct vfsmount *mnt)
4221 {
4222 	return get_sb_bdev(fs_type, flags, dev_name, data, ext4_fill_super,mnt);
4223 }
4224 
4225 #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
4226 static struct file_system_type ext2_fs_type = {
4227 	.owner		= THIS_MODULE,
4228 	.name		= "ext2",
4229 	.get_sb		= ext4_get_sb,
4230 	.kill_sb	= kill_block_super,
4231 	.fs_flags	= FS_REQUIRES_DEV,
4232 };
4233 
4234 static inline void register_as_ext2(void)
4235 {
4236 	int err = register_filesystem(&ext2_fs_type);
4237 	if (err)
4238 		printk(KERN_WARNING
4239 		       "EXT4-fs: Unable to register as ext2 (%d)\n", err);
4240 }
4241 
4242 static inline void unregister_as_ext2(void)
4243 {
4244 	unregister_filesystem(&ext2_fs_type);
4245 }
4246 MODULE_ALIAS("ext2");
4247 #else
4248 static inline void register_as_ext2(void) { }
4249 static inline void unregister_as_ext2(void) { }
4250 #endif
4251 
4252 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
4253 static inline void register_as_ext3(void)
4254 {
4255 	int err = register_filesystem(&ext3_fs_type);
4256 	if (err)
4257 		printk(KERN_WARNING
4258 		       "EXT4-fs: Unable to register as ext3 (%d)\n", err);
4259 }
4260 
4261 static inline void unregister_as_ext3(void)
4262 {
4263 	unregister_filesystem(&ext3_fs_type);
4264 }
4265 MODULE_ALIAS("ext3");
4266 #else
4267 static inline void register_as_ext3(void) { }
4268 static inline void unregister_as_ext3(void) { }
4269 #endif
4270 
4271 static struct file_system_type ext4_fs_type = {
4272 	.owner		= THIS_MODULE,
4273 	.name		= "ext4",
4274 	.get_sb		= ext4_get_sb,
4275 	.kill_sb	= kill_block_super,
4276 	.fs_flags	= FS_REQUIRES_DEV,
4277 };
4278 
4279 static int __init init_ext4_fs(void)
4280 {
4281 	int err;
4282 
4283 	ext4_check_flag_values();
4284 	err = init_ext4_system_zone();
4285 	if (err)
4286 		return err;
4287 	ext4_kset = kset_create_and_add("ext4", NULL, fs_kobj);
4288 	if (!ext4_kset)
4289 		goto out4;
4290 	ext4_proc_root = proc_mkdir("fs/ext4", NULL);
4291 	err = init_ext4_mballoc();
4292 	if (err)
4293 		goto out3;
4294 
4295 	err = init_ext4_xattr();
4296 	if (err)
4297 		goto out2;
4298 	err = init_inodecache();
4299 	if (err)
4300 		goto out1;
4301 	register_as_ext2();
4302 	register_as_ext3();
4303 	err = register_filesystem(&ext4_fs_type);
4304 	if (err)
4305 		goto out;
4306 	return 0;
4307 out:
4308 	unregister_as_ext2();
4309 	unregister_as_ext3();
4310 	destroy_inodecache();
4311 out1:
4312 	exit_ext4_xattr();
4313 out2:
4314 	exit_ext4_mballoc();
4315 out3:
4316 	remove_proc_entry("fs/ext4", NULL);
4317 	kset_unregister(ext4_kset);
4318 out4:
4319 	exit_ext4_system_zone();
4320 	return err;
4321 }
4322 
4323 static void __exit exit_ext4_fs(void)
4324 {
4325 	unregister_as_ext2();
4326 	unregister_as_ext3();
4327 	unregister_filesystem(&ext4_fs_type);
4328 	destroy_inodecache();
4329 	exit_ext4_xattr();
4330 	exit_ext4_mballoc();
4331 	remove_proc_entry("fs/ext4", NULL);
4332 	kset_unregister(ext4_kset);
4333 	exit_ext4_system_zone();
4334 }
4335 
4336 MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
4337 MODULE_DESCRIPTION("Fourth Extended Filesystem");
4338 MODULE_LICENSE("GPL");
4339 module_init(init_ext4_fs)
4340 module_exit(exit_ext4_fs)
4341