xref: /linux/fs/ext4/super.c (revision c39b9fd728d8173ecda993524089fbc38211a17f)
1 /*
2  *  linux/fs/ext4/super.c
3  *
4  * Copyright (C) 1992, 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  *
9  *  from
10  *
11  *  linux/fs/minix/inode.c
12  *
13  *  Copyright (C) 1991, 1992  Linus Torvalds
14  *
15  *  Big-endian to little-endian byte-swapping/bitmaps by
16  *        David S. Miller (davem@caip.rutgers.edu), 1995
17  */
18 
19 #include <linux/module.h>
20 #include <linux/string.h>
21 #include <linux/fs.h>
22 #include <linux/time.h>
23 #include <linux/vmalloc.h>
24 #include <linux/jbd2.h>
25 #include <linux/slab.h>
26 #include <linux/init.h>
27 #include <linux/blkdev.h>
28 #include <linux/parser.h>
29 #include <linux/buffer_head.h>
30 #include <linux/exportfs.h>
31 #include <linux/vfs.h>
32 #include <linux/random.h>
33 #include <linux/mount.h>
34 #include <linux/namei.h>
35 #include <linux/quotaops.h>
36 #include <linux/seq_file.h>
37 #include <linux/proc_fs.h>
38 #include <linux/ctype.h>
39 #include <linux/log2.h>
40 #include <linux/crc16.h>
41 #include <linux/cleancache.h>
42 #include <asm/uaccess.h>
43 
44 #include <linux/kthread.h>
45 #include <linux/freezer.h>
46 
47 #include "ext4.h"
48 #include "ext4_extents.h"	/* Needed for trace points definition */
49 #include "ext4_jbd2.h"
50 #include "xattr.h"
51 #include "acl.h"
52 #include "mballoc.h"
53 
54 #define CREATE_TRACE_POINTS
55 #include <trace/events/ext4.h>
56 
57 static struct proc_dir_entry *ext4_proc_root;
58 static struct kset *ext4_kset;
59 static struct ext4_lazy_init *ext4_li_info;
60 static struct mutex ext4_li_mtx;
61 static struct ext4_features *ext4_feat;
62 
63 static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
64 			     unsigned long journal_devnum);
65 static int ext4_show_options(struct seq_file *seq, struct dentry *root);
66 static int ext4_commit_super(struct super_block *sb, int sync);
67 static void ext4_mark_recovery_complete(struct super_block *sb,
68 					struct ext4_super_block *es);
69 static void ext4_clear_journal_err(struct super_block *sb,
70 				   struct ext4_super_block *es);
71 static int ext4_sync_fs(struct super_block *sb, int wait);
72 static int ext4_remount(struct super_block *sb, int *flags, char *data);
73 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf);
74 static int ext4_unfreeze(struct super_block *sb);
75 static int ext4_freeze(struct super_block *sb);
76 static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
77 		       const char *dev_name, void *data);
78 static inline int ext2_feature_set_ok(struct super_block *sb);
79 static inline int ext3_feature_set_ok(struct super_block *sb);
80 static int ext4_feature_set_ok(struct super_block *sb, int readonly);
81 static void ext4_destroy_lazyinit_thread(void);
82 static void ext4_unregister_li_request(struct super_block *sb);
83 static void ext4_clear_request_list(void);
84 static int ext4_reserve_clusters(struct ext4_sb_info *, ext4_fsblk_t);
85 
86 #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
87 static struct file_system_type ext2_fs_type = {
88 	.owner		= THIS_MODULE,
89 	.name		= "ext2",
90 	.mount		= ext4_mount,
91 	.kill_sb	= kill_block_super,
92 	.fs_flags	= FS_REQUIRES_DEV,
93 };
94 MODULE_ALIAS_FS("ext2");
95 MODULE_ALIAS("ext2");
96 #define IS_EXT2_SB(sb) ((sb)->s_bdev->bd_holder == &ext2_fs_type)
97 #else
98 #define IS_EXT2_SB(sb) (0)
99 #endif
100 
101 
102 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
103 static struct file_system_type ext3_fs_type = {
104 	.owner		= THIS_MODULE,
105 	.name		= "ext3",
106 	.mount		= ext4_mount,
107 	.kill_sb	= kill_block_super,
108 	.fs_flags	= FS_REQUIRES_DEV,
109 };
110 MODULE_ALIAS_FS("ext3");
111 MODULE_ALIAS("ext3");
112 #define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type)
113 #else
114 #define IS_EXT3_SB(sb) (0)
115 #endif
116 
117 static int ext4_verify_csum_type(struct super_block *sb,
118 				 struct ext4_super_block *es)
119 {
120 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
121 					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
122 		return 1;
123 
124 	return es->s_checksum_type == EXT4_CRC32C_CHKSUM;
125 }
126 
127 static __le32 ext4_superblock_csum(struct super_block *sb,
128 				   struct ext4_super_block *es)
129 {
130 	struct ext4_sb_info *sbi = EXT4_SB(sb);
131 	int offset = offsetof(struct ext4_super_block, s_checksum);
132 	__u32 csum;
133 
134 	csum = ext4_chksum(sbi, ~0, (char *)es, offset);
135 
136 	return cpu_to_le32(csum);
137 }
138 
139 int ext4_superblock_csum_verify(struct super_block *sb,
140 				struct ext4_super_block *es)
141 {
142 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
143 				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
144 		return 1;
145 
146 	return es->s_checksum == ext4_superblock_csum(sb, es);
147 }
148 
149 void ext4_superblock_csum_set(struct super_block *sb)
150 {
151 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
152 
153 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
154 		EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
155 		return;
156 
157 	es->s_checksum = ext4_superblock_csum(sb, es);
158 }
159 
160 void *ext4_kvmalloc(size_t size, gfp_t flags)
161 {
162 	void *ret;
163 
164 	ret = kmalloc(size, flags);
165 	if (!ret)
166 		ret = __vmalloc(size, flags, PAGE_KERNEL);
167 	return ret;
168 }
169 
170 void *ext4_kvzalloc(size_t size, gfp_t flags)
171 {
172 	void *ret;
173 
174 	ret = kzalloc(size, flags);
175 	if (!ret)
176 		ret = __vmalloc(size, flags | __GFP_ZERO, PAGE_KERNEL);
177 	return ret;
178 }
179 
180 void ext4_kvfree(void *ptr)
181 {
182 	if (is_vmalloc_addr(ptr))
183 		vfree(ptr);
184 	else
185 		kfree(ptr);
186 
187 }
188 
189 ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
190 			       struct ext4_group_desc *bg)
191 {
192 	return le32_to_cpu(bg->bg_block_bitmap_lo) |
193 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
194 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_block_bitmap_hi) << 32 : 0);
195 }
196 
197 ext4_fsblk_t ext4_inode_bitmap(struct super_block *sb,
198 			       struct ext4_group_desc *bg)
199 {
200 	return le32_to_cpu(bg->bg_inode_bitmap_lo) |
201 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
202 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_bitmap_hi) << 32 : 0);
203 }
204 
205 ext4_fsblk_t ext4_inode_table(struct super_block *sb,
206 			      struct ext4_group_desc *bg)
207 {
208 	return le32_to_cpu(bg->bg_inode_table_lo) |
209 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
210 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_table_hi) << 32 : 0);
211 }
212 
213 __u32 ext4_free_group_clusters(struct super_block *sb,
214 			       struct ext4_group_desc *bg)
215 {
216 	return le16_to_cpu(bg->bg_free_blocks_count_lo) |
217 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
218 		 (__u32)le16_to_cpu(bg->bg_free_blocks_count_hi) << 16 : 0);
219 }
220 
221 __u32 ext4_free_inodes_count(struct super_block *sb,
222 			      struct ext4_group_desc *bg)
223 {
224 	return le16_to_cpu(bg->bg_free_inodes_count_lo) |
225 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
226 		 (__u32)le16_to_cpu(bg->bg_free_inodes_count_hi) << 16 : 0);
227 }
228 
229 __u32 ext4_used_dirs_count(struct super_block *sb,
230 			      struct ext4_group_desc *bg)
231 {
232 	return le16_to_cpu(bg->bg_used_dirs_count_lo) |
233 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
234 		 (__u32)le16_to_cpu(bg->bg_used_dirs_count_hi) << 16 : 0);
235 }
236 
237 __u32 ext4_itable_unused_count(struct super_block *sb,
238 			      struct ext4_group_desc *bg)
239 {
240 	return le16_to_cpu(bg->bg_itable_unused_lo) |
241 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
242 		 (__u32)le16_to_cpu(bg->bg_itable_unused_hi) << 16 : 0);
243 }
244 
245 void ext4_block_bitmap_set(struct super_block *sb,
246 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
247 {
248 	bg->bg_block_bitmap_lo = cpu_to_le32((u32)blk);
249 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
250 		bg->bg_block_bitmap_hi = cpu_to_le32(blk >> 32);
251 }
252 
253 void ext4_inode_bitmap_set(struct super_block *sb,
254 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
255 {
256 	bg->bg_inode_bitmap_lo  = cpu_to_le32((u32)blk);
257 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
258 		bg->bg_inode_bitmap_hi = cpu_to_le32(blk >> 32);
259 }
260 
261 void ext4_inode_table_set(struct super_block *sb,
262 			  struct ext4_group_desc *bg, ext4_fsblk_t blk)
263 {
264 	bg->bg_inode_table_lo = cpu_to_le32((u32)blk);
265 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
266 		bg->bg_inode_table_hi = cpu_to_le32(blk >> 32);
267 }
268 
269 void ext4_free_group_clusters_set(struct super_block *sb,
270 				  struct ext4_group_desc *bg, __u32 count)
271 {
272 	bg->bg_free_blocks_count_lo = cpu_to_le16((__u16)count);
273 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
274 		bg->bg_free_blocks_count_hi = cpu_to_le16(count >> 16);
275 }
276 
277 void ext4_free_inodes_set(struct super_block *sb,
278 			  struct ext4_group_desc *bg, __u32 count)
279 {
280 	bg->bg_free_inodes_count_lo = cpu_to_le16((__u16)count);
281 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
282 		bg->bg_free_inodes_count_hi = cpu_to_le16(count >> 16);
283 }
284 
285 void ext4_used_dirs_set(struct super_block *sb,
286 			  struct ext4_group_desc *bg, __u32 count)
287 {
288 	bg->bg_used_dirs_count_lo = cpu_to_le16((__u16)count);
289 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
290 		bg->bg_used_dirs_count_hi = cpu_to_le16(count >> 16);
291 }
292 
293 void ext4_itable_unused_set(struct super_block *sb,
294 			  struct ext4_group_desc *bg, __u32 count)
295 {
296 	bg->bg_itable_unused_lo = cpu_to_le16((__u16)count);
297 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
298 		bg->bg_itable_unused_hi = cpu_to_le16(count >> 16);
299 }
300 
301 
302 static void __save_error_info(struct super_block *sb, const char *func,
303 			    unsigned int line)
304 {
305 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
306 
307 	EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
308 	es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
309 	es->s_last_error_time = cpu_to_le32(get_seconds());
310 	strncpy(es->s_last_error_func, func, sizeof(es->s_last_error_func));
311 	es->s_last_error_line = cpu_to_le32(line);
312 	if (!es->s_first_error_time) {
313 		es->s_first_error_time = es->s_last_error_time;
314 		strncpy(es->s_first_error_func, func,
315 			sizeof(es->s_first_error_func));
316 		es->s_first_error_line = cpu_to_le32(line);
317 		es->s_first_error_ino = es->s_last_error_ino;
318 		es->s_first_error_block = es->s_last_error_block;
319 	}
320 	/*
321 	 * Start the daily error reporting function if it hasn't been
322 	 * started already
323 	 */
324 	if (!es->s_error_count)
325 		mod_timer(&EXT4_SB(sb)->s_err_report, jiffies + 24*60*60*HZ);
326 	le32_add_cpu(&es->s_error_count, 1);
327 }
328 
329 static void save_error_info(struct super_block *sb, const char *func,
330 			    unsigned int line)
331 {
332 	__save_error_info(sb, func, line);
333 	ext4_commit_super(sb, 1);
334 }
335 
336 /*
337  * The del_gendisk() function uninitializes the disk-specific data
338  * structures, including the bdi structure, without telling anyone
339  * else.  Once this happens, any attempt to call mark_buffer_dirty()
340  * (for example, by ext4_commit_super), will cause a kernel OOPS.
341  * This is a kludge to prevent these oops until we can put in a proper
342  * hook in del_gendisk() to inform the VFS and file system layers.
343  */
344 static int block_device_ejected(struct super_block *sb)
345 {
346 	struct inode *bd_inode = sb->s_bdev->bd_inode;
347 	struct backing_dev_info *bdi = bd_inode->i_mapping->backing_dev_info;
348 
349 	return bdi->dev == NULL;
350 }
351 
352 static void ext4_journal_commit_callback(journal_t *journal, transaction_t *txn)
353 {
354 	struct super_block		*sb = journal->j_private;
355 	struct ext4_sb_info		*sbi = EXT4_SB(sb);
356 	int				error = is_journal_aborted(journal);
357 	struct ext4_journal_cb_entry	*jce;
358 
359 	BUG_ON(txn->t_state == T_FINISHED);
360 	spin_lock(&sbi->s_md_lock);
361 	while (!list_empty(&txn->t_private_list)) {
362 		jce = list_entry(txn->t_private_list.next,
363 				 struct ext4_journal_cb_entry, jce_list);
364 		list_del_init(&jce->jce_list);
365 		spin_unlock(&sbi->s_md_lock);
366 		jce->jce_func(sb, jce, error);
367 		spin_lock(&sbi->s_md_lock);
368 	}
369 	spin_unlock(&sbi->s_md_lock);
370 }
371 
372 /* Deal with the reporting of failure conditions on a filesystem such as
373  * inconsistencies detected or read IO failures.
374  *
375  * On ext2, we can store the error state of the filesystem in the
376  * superblock.  That is not possible on ext4, because we may have other
377  * write ordering constraints on the superblock which prevent us from
378  * writing it out straight away; and given that the journal is about to
379  * be aborted, we can't rely on the current, or future, transactions to
380  * write out the superblock safely.
381  *
382  * We'll just use the jbd2_journal_abort() error code to record an error in
383  * the journal instead.  On recovery, the journal will complain about
384  * that error until we've noted it down and cleared it.
385  */
386 
387 static void ext4_handle_error(struct super_block *sb)
388 {
389 	if (sb->s_flags & MS_RDONLY)
390 		return;
391 
392 	if (!test_opt(sb, ERRORS_CONT)) {
393 		journal_t *journal = EXT4_SB(sb)->s_journal;
394 
395 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
396 		if (journal)
397 			jbd2_journal_abort(journal, -EIO);
398 	}
399 	if (test_opt(sb, ERRORS_RO)) {
400 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
401 		sb->s_flags |= MS_RDONLY;
402 	}
403 	if (test_opt(sb, ERRORS_PANIC))
404 		panic("EXT4-fs (device %s): panic forced after error\n",
405 			sb->s_id);
406 }
407 
408 void __ext4_error(struct super_block *sb, const char *function,
409 		  unsigned int line, const char *fmt, ...)
410 {
411 	struct va_format vaf;
412 	va_list args;
413 
414 	va_start(args, fmt);
415 	vaf.fmt = fmt;
416 	vaf.va = &args;
417 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: comm %s: %pV\n",
418 	       sb->s_id, function, line, current->comm, &vaf);
419 	va_end(args);
420 	save_error_info(sb, function, line);
421 
422 	ext4_handle_error(sb);
423 }
424 
425 void ext4_error_inode(struct inode *inode, const char *function,
426 		      unsigned int line, ext4_fsblk_t block,
427 		      const char *fmt, ...)
428 {
429 	va_list args;
430 	struct va_format vaf;
431 	struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
432 
433 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
434 	es->s_last_error_block = cpu_to_le64(block);
435 	save_error_info(inode->i_sb, function, line);
436 	va_start(args, fmt);
437 	vaf.fmt = fmt;
438 	vaf.va = &args;
439 	if (block)
440 		printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
441 		       "inode #%lu: block %llu: comm %s: %pV\n",
442 		       inode->i_sb->s_id, function, line, inode->i_ino,
443 		       block, current->comm, &vaf);
444 	else
445 		printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
446 		       "inode #%lu: comm %s: %pV\n",
447 		       inode->i_sb->s_id, function, line, inode->i_ino,
448 		       current->comm, &vaf);
449 	va_end(args);
450 
451 	ext4_handle_error(inode->i_sb);
452 }
453 
454 void ext4_error_file(struct file *file, const char *function,
455 		     unsigned int line, ext4_fsblk_t block,
456 		     const char *fmt, ...)
457 {
458 	va_list args;
459 	struct va_format vaf;
460 	struct ext4_super_block *es;
461 	struct inode *inode = file_inode(file);
462 	char pathname[80], *path;
463 
464 	es = EXT4_SB(inode->i_sb)->s_es;
465 	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
466 	save_error_info(inode->i_sb, function, line);
467 	path = d_path(&(file->f_path), pathname, sizeof(pathname));
468 	if (IS_ERR(path))
469 		path = "(unknown)";
470 	va_start(args, fmt);
471 	vaf.fmt = fmt;
472 	vaf.va = &args;
473 	if (block)
474 		printk(KERN_CRIT
475 		       "EXT4-fs error (device %s): %s:%d: inode #%lu: "
476 		       "block %llu: comm %s: path %s: %pV\n",
477 		       inode->i_sb->s_id, function, line, inode->i_ino,
478 		       block, current->comm, path, &vaf);
479 	else
480 		printk(KERN_CRIT
481 		       "EXT4-fs error (device %s): %s:%d: inode #%lu: "
482 		       "comm %s: path %s: %pV\n",
483 		       inode->i_sb->s_id, function, line, inode->i_ino,
484 		       current->comm, path, &vaf);
485 	va_end(args);
486 
487 	ext4_handle_error(inode->i_sb);
488 }
489 
490 const char *ext4_decode_error(struct super_block *sb, int errno,
491 			      char nbuf[16])
492 {
493 	char *errstr = NULL;
494 
495 	switch (errno) {
496 	case -EIO:
497 		errstr = "IO failure";
498 		break;
499 	case -ENOMEM:
500 		errstr = "Out of memory";
501 		break;
502 	case -EROFS:
503 		if (!sb || (EXT4_SB(sb)->s_journal &&
504 			    EXT4_SB(sb)->s_journal->j_flags & JBD2_ABORT))
505 			errstr = "Journal has aborted";
506 		else
507 			errstr = "Readonly filesystem";
508 		break;
509 	default:
510 		/* If the caller passed in an extra buffer for unknown
511 		 * errors, textualise them now.  Else we just return
512 		 * NULL. */
513 		if (nbuf) {
514 			/* Check for truncated error codes... */
515 			if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
516 				errstr = nbuf;
517 		}
518 		break;
519 	}
520 
521 	return errstr;
522 }
523 
524 /* __ext4_std_error decodes expected errors from journaling functions
525  * automatically and invokes the appropriate error response.  */
526 
527 void __ext4_std_error(struct super_block *sb, const char *function,
528 		      unsigned int line, int errno)
529 {
530 	char nbuf[16];
531 	const char *errstr;
532 
533 	/* Special case: if the error is EROFS, and we're not already
534 	 * inside a transaction, then there's really no point in logging
535 	 * an error. */
536 	if (errno == -EROFS && journal_current_handle() == NULL &&
537 	    (sb->s_flags & MS_RDONLY))
538 		return;
539 
540 	errstr = ext4_decode_error(sb, errno, nbuf);
541 	printk(KERN_CRIT "EXT4-fs error (device %s) in %s:%d: %s\n",
542 	       sb->s_id, function, line, errstr);
543 	save_error_info(sb, function, line);
544 
545 	ext4_handle_error(sb);
546 }
547 
548 /*
549  * ext4_abort is a much stronger failure handler than ext4_error.  The
550  * abort function may be used to deal with unrecoverable failures such
551  * as journal IO errors or ENOMEM at a critical moment in log management.
552  *
553  * We unconditionally force the filesystem into an ABORT|READONLY state,
554  * unless the error response on the fs has been set to panic in which
555  * case we take the easy way out and panic immediately.
556  */
557 
558 void __ext4_abort(struct super_block *sb, const char *function,
559 		unsigned int line, const char *fmt, ...)
560 {
561 	va_list args;
562 
563 	save_error_info(sb, function, line);
564 	va_start(args, fmt);
565 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: ", sb->s_id,
566 	       function, line);
567 	vprintk(fmt, args);
568 	printk("\n");
569 	va_end(args);
570 
571 	if ((sb->s_flags & MS_RDONLY) == 0) {
572 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
573 		sb->s_flags |= MS_RDONLY;
574 		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
575 		if (EXT4_SB(sb)->s_journal)
576 			jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
577 		save_error_info(sb, function, line);
578 	}
579 	if (test_opt(sb, ERRORS_PANIC))
580 		panic("EXT4-fs panic from previous error\n");
581 }
582 
583 void ext4_msg(struct super_block *sb, const char *prefix, const char *fmt, ...)
584 {
585 	struct va_format vaf;
586 	va_list args;
587 
588 	va_start(args, fmt);
589 	vaf.fmt = fmt;
590 	vaf.va = &args;
591 	printk("%sEXT4-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
592 	va_end(args);
593 }
594 
595 void __ext4_warning(struct super_block *sb, const char *function,
596 		    unsigned int line, const char *fmt, ...)
597 {
598 	struct va_format vaf;
599 	va_list args;
600 
601 	va_start(args, fmt);
602 	vaf.fmt = fmt;
603 	vaf.va = &args;
604 	printk(KERN_WARNING "EXT4-fs warning (device %s): %s:%d: %pV\n",
605 	       sb->s_id, function, line, &vaf);
606 	va_end(args);
607 }
608 
609 void __ext4_grp_locked_error(const char *function, unsigned int line,
610 			     struct super_block *sb, ext4_group_t grp,
611 			     unsigned long ino, ext4_fsblk_t block,
612 			     const char *fmt, ...)
613 __releases(bitlock)
614 __acquires(bitlock)
615 {
616 	struct va_format vaf;
617 	va_list args;
618 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
619 
620 	es->s_last_error_ino = cpu_to_le32(ino);
621 	es->s_last_error_block = cpu_to_le64(block);
622 	__save_error_info(sb, function, line);
623 
624 	va_start(args, fmt);
625 
626 	vaf.fmt = fmt;
627 	vaf.va = &args;
628 	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: group %u, ",
629 	       sb->s_id, function, line, grp);
630 	if (ino)
631 		printk(KERN_CONT "inode %lu: ", ino);
632 	if (block)
633 		printk(KERN_CONT "block %llu:", (unsigned long long) block);
634 	printk(KERN_CONT "%pV\n", &vaf);
635 	va_end(args);
636 
637 	if (test_opt(sb, ERRORS_CONT)) {
638 		ext4_commit_super(sb, 0);
639 		return;
640 	}
641 
642 	ext4_unlock_group(sb, grp);
643 	ext4_handle_error(sb);
644 	/*
645 	 * We only get here in the ERRORS_RO case; relocking the group
646 	 * may be dangerous, but nothing bad will happen since the
647 	 * filesystem will have already been marked read/only and the
648 	 * journal has been aborted.  We return 1 as a hint to callers
649 	 * who might what to use the return value from
650 	 * ext4_grp_locked_error() to distinguish between the
651 	 * ERRORS_CONT and ERRORS_RO case, and perhaps return more
652 	 * aggressively from the ext4 function in question, with a
653 	 * more appropriate error code.
654 	 */
655 	ext4_lock_group(sb, grp);
656 	return;
657 }
658 
659 void ext4_update_dynamic_rev(struct super_block *sb)
660 {
661 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
662 
663 	if (le32_to_cpu(es->s_rev_level) > EXT4_GOOD_OLD_REV)
664 		return;
665 
666 	ext4_warning(sb,
667 		     "updating to rev %d because of new feature flag, "
668 		     "running e2fsck is recommended",
669 		     EXT4_DYNAMIC_REV);
670 
671 	es->s_first_ino = cpu_to_le32(EXT4_GOOD_OLD_FIRST_INO);
672 	es->s_inode_size = cpu_to_le16(EXT4_GOOD_OLD_INODE_SIZE);
673 	es->s_rev_level = cpu_to_le32(EXT4_DYNAMIC_REV);
674 	/* leave es->s_feature_*compat flags alone */
675 	/* es->s_uuid will be set by e2fsck if empty */
676 
677 	/*
678 	 * The rest of the superblock fields should be zero, and if not it
679 	 * means they are likely already in use, so leave them alone.  We
680 	 * can leave it up to e2fsck to clean up any inconsistencies there.
681 	 */
682 }
683 
684 /*
685  * Open the external journal device
686  */
687 static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb)
688 {
689 	struct block_device *bdev;
690 	char b[BDEVNAME_SIZE];
691 
692 	bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb);
693 	if (IS_ERR(bdev))
694 		goto fail;
695 	return bdev;
696 
697 fail:
698 	ext4_msg(sb, KERN_ERR, "failed to open journal device %s: %ld",
699 			__bdevname(dev, b), PTR_ERR(bdev));
700 	return NULL;
701 }
702 
703 /*
704  * Release the journal device
705  */
706 static int ext4_blkdev_put(struct block_device *bdev)
707 {
708 	return blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
709 }
710 
711 static int ext4_blkdev_remove(struct ext4_sb_info *sbi)
712 {
713 	struct block_device *bdev;
714 	int ret = -ENODEV;
715 
716 	bdev = sbi->journal_bdev;
717 	if (bdev) {
718 		ret = ext4_blkdev_put(bdev);
719 		sbi->journal_bdev = NULL;
720 	}
721 	return ret;
722 }
723 
724 static inline struct inode *orphan_list_entry(struct list_head *l)
725 {
726 	return &list_entry(l, struct ext4_inode_info, i_orphan)->vfs_inode;
727 }
728 
729 static void dump_orphan_list(struct super_block *sb, struct ext4_sb_info *sbi)
730 {
731 	struct list_head *l;
732 
733 	ext4_msg(sb, KERN_ERR, "sb orphan head is %d",
734 		 le32_to_cpu(sbi->s_es->s_last_orphan));
735 
736 	printk(KERN_ERR "sb_info orphan list:\n");
737 	list_for_each(l, &sbi->s_orphan) {
738 		struct inode *inode = orphan_list_entry(l);
739 		printk(KERN_ERR "  "
740 		       "inode %s:%lu at %p: mode %o, nlink %d, next %d\n",
741 		       inode->i_sb->s_id, inode->i_ino, inode,
742 		       inode->i_mode, inode->i_nlink,
743 		       NEXT_ORPHAN(inode));
744 	}
745 }
746 
747 static void ext4_put_super(struct super_block *sb)
748 {
749 	struct ext4_sb_info *sbi = EXT4_SB(sb);
750 	struct ext4_super_block *es = sbi->s_es;
751 	int i, err;
752 
753 	ext4_unregister_li_request(sb);
754 	dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
755 
756 	flush_workqueue(sbi->dio_unwritten_wq);
757 	destroy_workqueue(sbi->dio_unwritten_wq);
758 
759 	if (sbi->s_journal) {
760 		err = jbd2_journal_destroy(sbi->s_journal);
761 		sbi->s_journal = NULL;
762 		if (err < 0)
763 			ext4_abort(sb, "Couldn't clean up the journal");
764 	}
765 
766 	ext4_es_unregister_shrinker(sb);
767 	del_timer(&sbi->s_err_report);
768 	ext4_release_system_zone(sb);
769 	ext4_mb_release(sb);
770 	ext4_ext_release(sb);
771 	ext4_xattr_put_super(sb);
772 
773 	if (!(sb->s_flags & MS_RDONLY)) {
774 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
775 		es->s_state = cpu_to_le16(sbi->s_mount_state);
776 	}
777 	if (!(sb->s_flags & MS_RDONLY))
778 		ext4_commit_super(sb, 1);
779 
780 	if (sbi->s_proc) {
781 		remove_proc_entry("options", sbi->s_proc);
782 		remove_proc_entry(sb->s_id, ext4_proc_root);
783 	}
784 	kobject_del(&sbi->s_kobj);
785 
786 	for (i = 0; i < sbi->s_gdb_count; i++)
787 		brelse(sbi->s_group_desc[i]);
788 	ext4_kvfree(sbi->s_group_desc);
789 	ext4_kvfree(sbi->s_flex_groups);
790 	percpu_counter_destroy(&sbi->s_freeclusters_counter);
791 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
792 	percpu_counter_destroy(&sbi->s_dirs_counter);
793 	percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
794 	percpu_counter_destroy(&sbi->s_extent_cache_cnt);
795 	brelse(sbi->s_sbh);
796 #ifdef CONFIG_QUOTA
797 	for (i = 0; i < MAXQUOTAS; i++)
798 		kfree(sbi->s_qf_names[i]);
799 #endif
800 
801 	/* Debugging code just in case the in-memory inode orphan list
802 	 * isn't empty.  The on-disk one can be non-empty if we've
803 	 * detected an error and taken the fs readonly, but the
804 	 * in-memory list had better be clean by this point. */
805 	if (!list_empty(&sbi->s_orphan))
806 		dump_orphan_list(sb, sbi);
807 	J_ASSERT(list_empty(&sbi->s_orphan));
808 
809 	invalidate_bdev(sb->s_bdev);
810 	if (sbi->journal_bdev && sbi->journal_bdev != sb->s_bdev) {
811 		/*
812 		 * Invalidate the journal device's buffers.  We don't want them
813 		 * floating about in memory - the physical journal device may
814 		 * hotswapped, and it breaks the `ro-after' testing code.
815 		 */
816 		sync_blockdev(sbi->journal_bdev);
817 		invalidate_bdev(sbi->journal_bdev);
818 		ext4_blkdev_remove(sbi);
819 	}
820 	if (sbi->s_mmp_tsk)
821 		kthread_stop(sbi->s_mmp_tsk);
822 	sb->s_fs_info = NULL;
823 	/*
824 	 * Now that we are completely done shutting down the
825 	 * superblock, we need to actually destroy the kobject.
826 	 */
827 	kobject_put(&sbi->s_kobj);
828 	wait_for_completion(&sbi->s_kobj_unregister);
829 	if (sbi->s_chksum_driver)
830 		crypto_free_shash(sbi->s_chksum_driver);
831 	kfree(sbi->s_blockgroup_lock);
832 	kfree(sbi);
833 }
834 
835 static struct kmem_cache *ext4_inode_cachep;
836 
837 /*
838  * Called inside transaction, so use GFP_NOFS
839  */
840 static struct inode *ext4_alloc_inode(struct super_block *sb)
841 {
842 	struct ext4_inode_info *ei;
843 
844 	ei = kmem_cache_alloc(ext4_inode_cachep, GFP_NOFS);
845 	if (!ei)
846 		return NULL;
847 
848 	ei->vfs_inode.i_version = 1;
849 	INIT_LIST_HEAD(&ei->i_prealloc_list);
850 	spin_lock_init(&ei->i_prealloc_lock);
851 	ext4_es_init_tree(&ei->i_es_tree);
852 	rwlock_init(&ei->i_es_lock);
853 	INIT_LIST_HEAD(&ei->i_es_lru);
854 	ei->i_es_lru_nr = 0;
855 	ei->i_reserved_data_blocks = 0;
856 	ei->i_reserved_meta_blocks = 0;
857 	ei->i_allocated_meta_blocks = 0;
858 	ei->i_da_metadata_calc_len = 0;
859 	ei->i_da_metadata_calc_last_lblock = 0;
860 	spin_lock_init(&(ei->i_block_reservation_lock));
861 #ifdef CONFIG_QUOTA
862 	ei->i_reserved_quota = 0;
863 #endif
864 	ei->jinode = NULL;
865 	INIT_LIST_HEAD(&ei->i_completed_io_list);
866 	spin_lock_init(&ei->i_completed_io_lock);
867 	ei->i_sync_tid = 0;
868 	ei->i_datasync_tid = 0;
869 	atomic_set(&ei->i_ioend_count, 0);
870 	atomic_set(&ei->i_unwritten, 0);
871 	INIT_WORK(&ei->i_unwritten_work, ext4_end_io_work);
872 
873 	return &ei->vfs_inode;
874 }
875 
876 static int ext4_drop_inode(struct inode *inode)
877 {
878 	int drop = generic_drop_inode(inode);
879 
880 	trace_ext4_drop_inode(inode, drop);
881 	return drop;
882 }
883 
884 static void ext4_i_callback(struct rcu_head *head)
885 {
886 	struct inode *inode = container_of(head, struct inode, i_rcu);
887 	kmem_cache_free(ext4_inode_cachep, EXT4_I(inode));
888 }
889 
890 static void ext4_destroy_inode(struct inode *inode)
891 {
892 	if (!list_empty(&(EXT4_I(inode)->i_orphan))) {
893 		ext4_msg(inode->i_sb, KERN_ERR,
894 			 "Inode %lu (%p): orphan list check failed!",
895 			 inode->i_ino, EXT4_I(inode));
896 		print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 16, 4,
897 				EXT4_I(inode), sizeof(struct ext4_inode_info),
898 				true);
899 		dump_stack();
900 	}
901 	call_rcu(&inode->i_rcu, ext4_i_callback);
902 }
903 
904 static void init_once(void *foo)
905 {
906 	struct ext4_inode_info *ei = (struct ext4_inode_info *) foo;
907 
908 	INIT_LIST_HEAD(&ei->i_orphan);
909 	init_rwsem(&ei->xattr_sem);
910 	init_rwsem(&ei->i_data_sem);
911 	inode_init_once(&ei->vfs_inode);
912 }
913 
914 static int init_inodecache(void)
915 {
916 	ext4_inode_cachep = kmem_cache_create("ext4_inode_cache",
917 					     sizeof(struct ext4_inode_info),
918 					     0, (SLAB_RECLAIM_ACCOUNT|
919 						SLAB_MEM_SPREAD),
920 					     init_once);
921 	if (ext4_inode_cachep == NULL)
922 		return -ENOMEM;
923 	return 0;
924 }
925 
926 static void destroy_inodecache(void)
927 {
928 	/*
929 	 * Make sure all delayed rcu free inodes are flushed before we
930 	 * destroy cache.
931 	 */
932 	rcu_barrier();
933 	kmem_cache_destroy(ext4_inode_cachep);
934 }
935 
936 void ext4_clear_inode(struct inode *inode)
937 {
938 	invalidate_inode_buffers(inode);
939 	clear_inode(inode);
940 	dquot_drop(inode);
941 	ext4_discard_preallocations(inode);
942 	ext4_es_remove_extent(inode, 0, EXT_MAX_BLOCKS);
943 	ext4_es_lru_del(inode);
944 	if (EXT4_I(inode)->jinode) {
945 		jbd2_journal_release_jbd_inode(EXT4_JOURNAL(inode),
946 					       EXT4_I(inode)->jinode);
947 		jbd2_free_inode(EXT4_I(inode)->jinode);
948 		EXT4_I(inode)->jinode = NULL;
949 	}
950 }
951 
952 static struct inode *ext4_nfs_get_inode(struct super_block *sb,
953 					u64 ino, u32 generation)
954 {
955 	struct inode *inode;
956 
957 	if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
958 		return ERR_PTR(-ESTALE);
959 	if (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
960 		return ERR_PTR(-ESTALE);
961 
962 	/* iget isn't really right if the inode is currently unallocated!!
963 	 *
964 	 * ext4_read_inode will return a bad_inode if the inode had been
965 	 * deleted, so we should be safe.
966 	 *
967 	 * Currently we don't know the generation for parent directory, so
968 	 * a generation of 0 means "accept any"
969 	 */
970 	inode = ext4_iget(sb, ino);
971 	if (IS_ERR(inode))
972 		return ERR_CAST(inode);
973 	if (generation && inode->i_generation != generation) {
974 		iput(inode);
975 		return ERR_PTR(-ESTALE);
976 	}
977 
978 	return inode;
979 }
980 
981 static struct dentry *ext4_fh_to_dentry(struct super_block *sb, struct fid *fid,
982 					int fh_len, int fh_type)
983 {
984 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
985 				    ext4_nfs_get_inode);
986 }
987 
988 static struct dentry *ext4_fh_to_parent(struct super_block *sb, struct fid *fid,
989 					int fh_len, int fh_type)
990 {
991 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
992 				    ext4_nfs_get_inode);
993 }
994 
995 /*
996  * Try to release metadata pages (indirect blocks, directories) which are
997  * mapped via the block device.  Since these pages could have journal heads
998  * which would prevent try_to_free_buffers() from freeing them, we must use
999  * jbd2 layer's try_to_free_buffers() function to release them.
1000  */
1001 static int bdev_try_to_free_page(struct super_block *sb, struct page *page,
1002 				 gfp_t wait)
1003 {
1004 	journal_t *journal = EXT4_SB(sb)->s_journal;
1005 
1006 	WARN_ON(PageChecked(page));
1007 	if (!page_has_buffers(page))
1008 		return 0;
1009 	if (journal)
1010 		return jbd2_journal_try_to_free_buffers(journal, page,
1011 							wait & ~__GFP_WAIT);
1012 	return try_to_free_buffers(page);
1013 }
1014 
1015 #ifdef CONFIG_QUOTA
1016 #define QTYPE2NAME(t) ((t) == USRQUOTA ? "user" : "group")
1017 #define QTYPE2MOPT(on, t) ((t) == USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
1018 
1019 static int ext4_write_dquot(struct dquot *dquot);
1020 static int ext4_acquire_dquot(struct dquot *dquot);
1021 static int ext4_release_dquot(struct dquot *dquot);
1022 static int ext4_mark_dquot_dirty(struct dquot *dquot);
1023 static int ext4_write_info(struct super_block *sb, int type);
1024 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
1025 			 struct path *path);
1026 static int ext4_quota_on_sysfile(struct super_block *sb, int type,
1027 				 int format_id);
1028 static int ext4_quota_off(struct super_block *sb, int type);
1029 static int ext4_quota_off_sysfile(struct super_block *sb, int type);
1030 static int ext4_quota_on_mount(struct super_block *sb, int type);
1031 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
1032 			       size_t len, loff_t off);
1033 static ssize_t ext4_quota_write(struct super_block *sb, int type,
1034 				const char *data, size_t len, loff_t off);
1035 static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
1036 			     unsigned int flags);
1037 static int ext4_enable_quotas(struct super_block *sb);
1038 
1039 static const struct dquot_operations ext4_quota_operations = {
1040 	.get_reserved_space = ext4_get_reserved_space,
1041 	.write_dquot	= ext4_write_dquot,
1042 	.acquire_dquot	= ext4_acquire_dquot,
1043 	.release_dquot	= ext4_release_dquot,
1044 	.mark_dirty	= ext4_mark_dquot_dirty,
1045 	.write_info	= ext4_write_info,
1046 	.alloc_dquot	= dquot_alloc,
1047 	.destroy_dquot	= dquot_destroy,
1048 };
1049 
1050 static const struct quotactl_ops ext4_qctl_operations = {
1051 	.quota_on	= ext4_quota_on,
1052 	.quota_off	= ext4_quota_off,
1053 	.quota_sync	= dquot_quota_sync,
1054 	.get_info	= dquot_get_dqinfo,
1055 	.set_info	= dquot_set_dqinfo,
1056 	.get_dqblk	= dquot_get_dqblk,
1057 	.set_dqblk	= dquot_set_dqblk
1058 };
1059 
1060 static const struct quotactl_ops ext4_qctl_sysfile_operations = {
1061 	.quota_on_meta	= ext4_quota_on_sysfile,
1062 	.quota_off	= ext4_quota_off_sysfile,
1063 	.quota_sync	= dquot_quota_sync,
1064 	.get_info	= dquot_get_dqinfo,
1065 	.set_info	= dquot_set_dqinfo,
1066 	.get_dqblk	= dquot_get_dqblk,
1067 	.set_dqblk	= dquot_set_dqblk
1068 };
1069 #endif
1070 
1071 static const struct super_operations ext4_sops = {
1072 	.alloc_inode	= ext4_alloc_inode,
1073 	.destroy_inode	= ext4_destroy_inode,
1074 	.write_inode	= ext4_write_inode,
1075 	.dirty_inode	= ext4_dirty_inode,
1076 	.drop_inode	= ext4_drop_inode,
1077 	.evict_inode	= ext4_evict_inode,
1078 	.put_super	= ext4_put_super,
1079 	.sync_fs	= ext4_sync_fs,
1080 	.freeze_fs	= ext4_freeze,
1081 	.unfreeze_fs	= ext4_unfreeze,
1082 	.statfs		= ext4_statfs,
1083 	.remount_fs	= ext4_remount,
1084 	.show_options	= ext4_show_options,
1085 #ifdef CONFIG_QUOTA
1086 	.quota_read	= ext4_quota_read,
1087 	.quota_write	= ext4_quota_write,
1088 #endif
1089 	.bdev_try_to_free_page = bdev_try_to_free_page,
1090 };
1091 
1092 static const struct super_operations ext4_nojournal_sops = {
1093 	.alloc_inode	= ext4_alloc_inode,
1094 	.destroy_inode	= ext4_destroy_inode,
1095 	.write_inode	= ext4_write_inode,
1096 	.dirty_inode	= ext4_dirty_inode,
1097 	.drop_inode	= ext4_drop_inode,
1098 	.evict_inode	= ext4_evict_inode,
1099 	.put_super	= ext4_put_super,
1100 	.statfs		= ext4_statfs,
1101 	.remount_fs	= ext4_remount,
1102 	.show_options	= ext4_show_options,
1103 #ifdef CONFIG_QUOTA
1104 	.quota_read	= ext4_quota_read,
1105 	.quota_write	= ext4_quota_write,
1106 #endif
1107 	.bdev_try_to_free_page = bdev_try_to_free_page,
1108 };
1109 
1110 static const struct export_operations ext4_export_ops = {
1111 	.fh_to_dentry = ext4_fh_to_dentry,
1112 	.fh_to_parent = ext4_fh_to_parent,
1113 	.get_parent = ext4_get_parent,
1114 };
1115 
1116 enum {
1117 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
1118 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
1119 	Opt_nouid32, Opt_debug, Opt_removed,
1120 	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
1121 	Opt_auto_da_alloc, Opt_noauto_da_alloc, Opt_noload,
1122 	Opt_commit, Opt_min_batch_time, Opt_max_batch_time,
1123 	Opt_journal_dev, Opt_journal_checksum, Opt_journal_async_commit,
1124 	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
1125 	Opt_data_err_abort, Opt_data_err_ignore,
1126 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
1127 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
1128 	Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err,
1129 	Opt_usrquota, Opt_grpquota, Opt_i_version,
1130 	Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_mblk_io_submit,
1131 	Opt_nomblk_io_submit, Opt_block_validity, Opt_noblock_validity,
1132 	Opt_inode_readahead_blks, Opt_journal_ioprio,
1133 	Opt_dioread_nolock, Opt_dioread_lock,
1134 	Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
1135 	Opt_max_dir_size_kb,
1136 };
1137 
1138 static const match_table_t tokens = {
1139 	{Opt_bsd_df, "bsddf"},
1140 	{Opt_minix_df, "minixdf"},
1141 	{Opt_grpid, "grpid"},
1142 	{Opt_grpid, "bsdgroups"},
1143 	{Opt_nogrpid, "nogrpid"},
1144 	{Opt_nogrpid, "sysvgroups"},
1145 	{Opt_resgid, "resgid=%u"},
1146 	{Opt_resuid, "resuid=%u"},
1147 	{Opt_sb, "sb=%u"},
1148 	{Opt_err_cont, "errors=continue"},
1149 	{Opt_err_panic, "errors=panic"},
1150 	{Opt_err_ro, "errors=remount-ro"},
1151 	{Opt_nouid32, "nouid32"},
1152 	{Opt_debug, "debug"},
1153 	{Opt_removed, "oldalloc"},
1154 	{Opt_removed, "orlov"},
1155 	{Opt_user_xattr, "user_xattr"},
1156 	{Opt_nouser_xattr, "nouser_xattr"},
1157 	{Opt_acl, "acl"},
1158 	{Opt_noacl, "noacl"},
1159 	{Opt_noload, "norecovery"},
1160 	{Opt_noload, "noload"},
1161 	{Opt_removed, "nobh"},
1162 	{Opt_removed, "bh"},
1163 	{Opt_commit, "commit=%u"},
1164 	{Opt_min_batch_time, "min_batch_time=%u"},
1165 	{Opt_max_batch_time, "max_batch_time=%u"},
1166 	{Opt_journal_dev, "journal_dev=%u"},
1167 	{Opt_journal_checksum, "journal_checksum"},
1168 	{Opt_journal_async_commit, "journal_async_commit"},
1169 	{Opt_abort, "abort"},
1170 	{Opt_data_journal, "data=journal"},
1171 	{Opt_data_ordered, "data=ordered"},
1172 	{Opt_data_writeback, "data=writeback"},
1173 	{Opt_data_err_abort, "data_err=abort"},
1174 	{Opt_data_err_ignore, "data_err=ignore"},
1175 	{Opt_offusrjquota, "usrjquota="},
1176 	{Opt_usrjquota, "usrjquota=%s"},
1177 	{Opt_offgrpjquota, "grpjquota="},
1178 	{Opt_grpjquota, "grpjquota=%s"},
1179 	{Opt_jqfmt_vfsold, "jqfmt=vfsold"},
1180 	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
1181 	{Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
1182 	{Opt_grpquota, "grpquota"},
1183 	{Opt_noquota, "noquota"},
1184 	{Opt_quota, "quota"},
1185 	{Opt_usrquota, "usrquota"},
1186 	{Opt_barrier, "barrier=%u"},
1187 	{Opt_barrier, "barrier"},
1188 	{Opt_nobarrier, "nobarrier"},
1189 	{Opt_i_version, "i_version"},
1190 	{Opt_stripe, "stripe=%u"},
1191 	{Opt_delalloc, "delalloc"},
1192 	{Opt_nodelalloc, "nodelalloc"},
1193 	{Opt_removed, "mblk_io_submit"},
1194 	{Opt_removed, "nomblk_io_submit"},
1195 	{Opt_block_validity, "block_validity"},
1196 	{Opt_noblock_validity, "noblock_validity"},
1197 	{Opt_inode_readahead_blks, "inode_readahead_blks=%u"},
1198 	{Opt_journal_ioprio, "journal_ioprio=%u"},
1199 	{Opt_auto_da_alloc, "auto_da_alloc=%u"},
1200 	{Opt_auto_da_alloc, "auto_da_alloc"},
1201 	{Opt_noauto_da_alloc, "noauto_da_alloc"},
1202 	{Opt_dioread_nolock, "dioread_nolock"},
1203 	{Opt_dioread_lock, "dioread_lock"},
1204 	{Opt_discard, "discard"},
1205 	{Opt_nodiscard, "nodiscard"},
1206 	{Opt_init_itable, "init_itable=%u"},
1207 	{Opt_init_itable, "init_itable"},
1208 	{Opt_noinit_itable, "noinit_itable"},
1209 	{Opt_max_dir_size_kb, "max_dir_size_kb=%u"},
1210 	{Opt_removed, "check=none"},	/* mount option from ext2/3 */
1211 	{Opt_removed, "nocheck"},	/* mount option from ext2/3 */
1212 	{Opt_removed, "reservation"},	/* mount option from ext2/3 */
1213 	{Opt_removed, "noreservation"}, /* mount option from ext2/3 */
1214 	{Opt_removed, "journal=%u"},	/* mount option from ext2/3 */
1215 	{Opt_err, NULL},
1216 };
1217 
1218 static ext4_fsblk_t get_sb_block(void **data)
1219 {
1220 	ext4_fsblk_t	sb_block;
1221 	char		*options = (char *) *data;
1222 
1223 	if (!options || strncmp(options, "sb=", 3) != 0)
1224 		return 1;	/* Default location */
1225 
1226 	options += 3;
1227 	/* TODO: use simple_strtoll with >32bit ext4 */
1228 	sb_block = simple_strtoul(options, &options, 0);
1229 	if (*options && *options != ',') {
1230 		printk(KERN_ERR "EXT4-fs: Invalid sb specification: %s\n",
1231 		       (char *) *data);
1232 		return 1;
1233 	}
1234 	if (*options == ',')
1235 		options++;
1236 	*data = (void *) options;
1237 
1238 	return sb_block;
1239 }
1240 
1241 #define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))
1242 static char deprecated_msg[] = "Mount option \"%s\" will be removed by %s\n"
1243 	"Contact linux-ext4@vger.kernel.org if you think we should keep it.\n";
1244 
1245 #ifdef CONFIG_QUOTA
1246 static int set_qf_name(struct super_block *sb, int qtype, substring_t *args)
1247 {
1248 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1249 	char *qname;
1250 	int ret = -1;
1251 
1252 	if (sb_any_quota_loaded(sb) &&
1253 		!sbi->s_qf_names[qtype]) {
1254 		ext4_msg(sb, KERN_ERR,
1255 			"Cannot change journaled "
1256 			"quota options when quota turned on");
1257 		return -1;
1258 	}
1259 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA)) {
1260 		ext4_msg(sb, KERN_ERR, "Cannot set journaled quota options "
1261 			 "when QUOTA feature is enabled");
1262 		return -1;
1263 	}
1264 	qname = match_strdup(args);
1265 	if (!qname) {
1266 		ext4_msg(sb, KERN_ERR,
1267 			"Not enough memory for storing quotafile name");
1268 		return -1;
1269 	}
1270 	if (sbi->s_qf_names[qtype]) {
1271 		if (strcmp(sbi->s_qf_names[qtype], qname) == 0)
1272 			ret = 1;
1273 		else
1274 			ext4_msg(sb, KERN_ERR,
1275 				 "%s quota file already specified",
1276 				 QTYPE2NAME(qtype));
1277 		goto errout;
1278 	}
1279 	if (strchr(qname, '/')) {
1280 		ext4_msg(sb, KERN_ERR,
1281 			"quotafile must be on filesystem root");
1282 		goto errout;
1283 	}
1284 	sbi->s_qf_names[qtype] = qname;
1285 	set_opt(sb, QUOTA);
1286 	return 1;
1287 errout:
1288 	kfree(qname);
1289 	return ret;
1290 }
1291 
1292 static int clear_qf_name(struct super_block *sb, int qtype)
1293 {
1294 
1295 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1296 
1297 	if (sb_any_quota_loaded(sb) &&
1298 		sbi->s_qf_names[qtype]) {
1299 		ext4_msg(sb, KERN_ERR, "Cannot change journaled quota options"
1300 			" when quota turned on");
1301 		return -1;
1302 	}
1303 	kfree(sbi->s_qf_names[qtype]);
1304 	sbi->s_qf_names[qtype] = NULL;
1305 	return 1;
1306 }
1307 #endif
1308 
1309 #define MOPT_SET	0x0001
1310 #define MOPT_CLEAR	0x0002
1311 #define MOPT_NOSUPPORT	0x0004
1312 #define MOPT_EXPLICIT	0x0008
1313 #define MOPT_CLEAR_ERR	0x0010
1314 #define MOPT_GTE0	0x0020
1315 #ifdef CONFIG_QUOTA
1316 #define MOPT_Q		0
1317 #define MOPT_QFMT	0x0040
1318 #else
1319 #define MOPT_Q		MOPT_NOSUPPORT
1320 #define MOPT_QFMT	MOPT_NOSUPPORT
1321 #endif
1322 #define MOPT_DATAJ	0x0080
1323 #define MOPT_NO_EXT2	0x0100
1324 #define MOPT_NO_EXT3	0x0200
1325 #define MOPT_EXT4_ONLY	(MOPT_NO_EXT2 | MOPT_NO_EXT3)
1326 
1327 static const struct mount_opts {
1328 	int	token;
1329 	int	mount_opt;
1330 	int	flags;
1331 } ext4_mount_opts[] = {
1332 	{Opt_minix_df, EXT4_MOUNT_MINIX_DF, MOPT_SET},
1333 	{Opt_bsd_df, EXT4_MOUNT_MINIX_DF, MOPT_CLEAR},
1334 	{Opt_grpid, EXT4_MOUNT_GRPID, MOPT_SET},
1335 	{Opt_nogrpid, EXT4_MOUNT_GRPID, MOPT_CLEAR},
1336 	{Opt_block_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_SET},
1337 	{Opt_noblock_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_CLEAR},
1338 	{Opt_dioread_nolock, EXT4_MOUNT_DIOREAD_NOLOCK,
1339 	 MOPT_EXT4_ONLY | MOPT_SET},
1340 	{Opt_dioread_lock, EXT4_MOUNT_DIOREAD_NOLOCK,
1341 	 MOPT_EXT4_ONLY | MOPT_CLEAR},
1342 	{Opt_discard, EXT4_MOUNT_DISCARD, MOPT_SET},
1343 	{Opt_nodiscard, EXT4_MOUNT_DISCARD, MOPT_CLEAR},
1344 	{Opt_delalloc, EXT4_MOUNT_DELALLOC,
1345 	 MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
1346 	{Opt_nodelalloc, EXT4_MOUNT_DELALLOC,
1347 	 MOPT_EXT4_ONLY | MOPT_CLEAR | MOPT_EXPLICIT},
1348 	{Opt_journal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,
1349 	 MOPT_EXT4_ONLY | MOPT_SET},
1350 	{Opt_journal_async_commit, (EXT4_MOUNT_JOURNAL_ASYNC_COMMIT |
1351 				    EXT4_MOUNT_JOURNAL_CHECKSUM),
1352 	 MOPT_EXT4_ONLY | MOPT_SET},
1353 	{Opt_noload, EXT4_MOUNT_NOLOAD, MOPT_NO_EXT2 | MOPT_SET},
1354 	{Opt_err_panic, EXT4_MOUNT_ERRORS_PANIC, MOPT_SET | MOPT_CLEAR_ERR},
1355 	{Opt_err_ro, EXT4_MOUNT_ERRORS_RO, MOPT_SET | MOPT_CLEAR_ERR},
1356 	{Opt_err_cont, EXT4_MOUNT_ERRORS_CONT, MOPT_SET | MOPT_CLEAR_ERR},
1357 	{Opt_data_err_abort, EXT4_MOUNT_DATA_ERR_ABORT,
1358 	 MOPT_NO_EXT2 | MOPT_SET},
1359 	{Opt_data_err_ignore, EXT4_MOUNT_DATA_ERR_ABORT,
1360 	 MOPT_NO_EXT2 | MOPT_CLEAR},
1361 	{Opt_barrier, EXT4_MOUNT_BARRIER, MOPT_SET},
1362 	{Opt_nobarrier, EXT4_MOUNT_BARRIER, MOPT_CLEAR},
1363 	{Opt_noauto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_SET},
1364 	{Opt_auto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_CLEAR},
1365 	{Opt_noinit_itable, EXT4_MOUNT_INIT_INODE_TABLE, MOPT_CLEAR},
1366 	{Opt_commit, 0, MOPT_GTE0},
1367 	{Opt_max_batch_time, 0, MOPT_GTE0},
1368 	{Opt_min_batch_time, 0, MOPT_GTE0},
1369 	{Opt_inode_readahead_blks, 0, MOPT_GTE0},
1370 	{Opt_init_itable, 0, MOPT_GTE0},
1371 	{Opt_stripe, 0, MOPT_GTE0},
1372 	{Opt_resuid, 0, MOPT_GTE0},
1373 	{Opt_resgid, 0, MOPT_GTE0},
1374 	{Opt_journal_dev, 0, MOPT_GTE0},
1375 	{Opt_journal_ioprio, 0, MOPT_GTE0},
1376 	{Opt_data_journal, EXT4_MOUNT_JOURNAL_DATA, MOPT_NO_EXT2 | MOPT_DATAJ},
1377 	{Opt_data_ordered, EXT4_MOUNT_ORDERED_DATA, MOPT_NO_EXT2 | MOPT_DATAJ},
1378 	{Opt_data_writeback, EXT4_MOUNT_WRITEBACK_DATA,
1379 	 MOPT_NO_EXT2 | MOPT_DATAJ},
1380 	{Opt_user_xattr, EXT4_MOUNT_XATTR_USER, MOPT_SET},
1381 	{Opt_nouser_xattr, EXT4_MOUNT_XATTR_USER, MOPT_CLEAR},
1382 #ifdef CONFIG_EXT4_FS_POSIX_ACL
1383 	{Opt_acl, EXT4_MOUNT_POSIX_ACL, MOPT_SET},
1384 	{Opt_noacl, EXT4_MOUNT_POSIX_ACL, MOPT_CLEAR},
1385 #else
1386 	{Opt_acl, 0, MOPT_NOSUPPORT},
1387 	{Opt_noacl, 0, MOPT_NOSUPPORT},
1388 #endif
1389 	{Opt_nouid32, EXT4_MOUNT_NO_UID32, MOPT_SET},
1390 	{Opt_debug, EXT4_MOUNT_DEBUG, MOPT_SET},
1391 	{Opt_quota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA, MOPT_SET | MOPT_Q},
1392 	{Opt_usrquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA,
1393 							MOPT_SET | MOPT_Q},
1394 	{Opt_grpquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_GRPQUOTA,
1395 							MOPT_SET | MOPT_Q},
1396 	{Opt_noquota, (EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA |
1397 		       EXT4_MOUNT_GRPQUOTA), MOPT_CLEAR | MOPT_Q},
1398 	{Opt_usrjquota, 0, MOPT_Q},
1399 	{Opt_grpjquota, 0, MOPT_Q},
1400 	{Opt_offusrjquota, 0, MOPT_Q},
1401 	{Opt_offgrpjquota, 0, MOPT_Q},
1402 	{Opt_jqfmt_vfsold, QFMT_VFS_OLD, MOPT_QFMT},
1403 	{Opt_jqfmt_vfsv0, QFMT_VFS_V0, MOPT_QFMT},
1404 	{Opt_jqfmt_vfsv1, QFMT_VFS_V1, MOPT_QFMT},
1405 	{Opt_max_dir_size_kb, 0, MOPT_GTE0},
1406 	{Opt_err, 0, 0}
1407 };
1408 
1409 static int handle_mount_opt(struct super_block *sb, char *opt, int token,
1410 			    substring_t *args, unsigned long *journal_devnum,
1411 			    unsigned int *journal_ioprio, int is_remount)
1412 {
1413 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1414 	const struct mount_opts *m;
1415 	kuid_t uid;
1416 	kgid_t gid;
1417 	int arg = 0;
1418 
1419 #ifdef CONFIG_QUOTA
1420 	if (token == Opt_usrjquota)
1421 		return set_qf_name(sb, USRQUOTA, &args[0]);
1422 	else if (token == Opt_grpjquota)
1423 		return set_qf_name(sb, GRPQUOTA, &args[0]);
1424 	else if (token == Opt_offusrjquota)
1425 		return clear_qf_name(sb, USRQUOTA);
1426 	else if (token == Opt_offgrpjquota)
1427 		return clear_qf_name(sb, GRPQUOTA);
1428 #endif
1429 	switch (token) {
1430 	case Opt_noacl:
1431 	case Opt_nouser_xattr:
1432 		ext4_msg(sb, KERN_WARNING, deprecated_msg, opt, "3.5");
1433 		break;
1434 	case Opt_sb:
1435 		return 1;	/* handled by get_sb_block() */
1436 	case Opt_removed:
1437 		ext4_msg(sb, KERN_WARNING, "Ignoring removed %s option", opt);
1438 		return 1;
1439 	case Opt_abort:
1440 		sbi->s_mount_flags |= EXT4_MF_FS_ABORTED;
1441 		return 1;
1442 	case Opt_i_version:
1443 		sb->s_flags |= MS_I_VERSION;
1444 		return 1;
1445 	}
1446 
1447 	for (m = ext4_mount_opts; m->token != Opt_err; m++)
1448 		if (token == m->token)
1449 			break;
1450 
1451 	if (m->token == Opt_err) {
1452 		ext4_msg(sb, KERN_ERR, "Unrecognized mount option \"%s\" "
1453 			 "or missing value", opt);
1454 		return -1;
1455 	}
1456 
1457 	if ((m->flags & MOPT_NO_EXT2) && IS_EXT2_SB(sb)) {
1458 		ext4_msg(sb, KERN_ERR,
1459 			 "Mount option \"%s\" incompatible with ext2", opt);
1460 		return -1;
1461 	}
1462 	if ((m->flags & MOPT_NO_EXT3) && IS_EXT3_SB(sb)) {
1463 		ext4_msg(sb, KERN_ERR,
1464 			 "Mount option \"%s\" incompatible with ext3", opt);
1465 		return -1;
1466 	}
1467 
1468 	if (args->from && match_int(args, &arg))
1469 		return -1;
1470 	if (args->from && (m->flags & MOPT_GTE0) && (arg < 0))
1471 		return -1;
1472 	if (m->flags & MOPT_EXPLICIT)
1473 		set_opt2(sb, EXPLICIT_DELALLOC);
1474 	if (m->flags & MOPT_CLEAR_ERR)
1475 		clear_opt(sb, ERRORS_MASK);
1476 	if (token == Opt_noquota && sb_any_quota_loaded(sb)) {
1477 		ext4_msg(sb, KERN_ERR, "Cannot change quota "
1478 			 "options when quota turned on");
1479 		return -1;
1480 	}
1481 
1482 	if (m->flags & MOPT_NOSUPPORT) {
1483 		ext4_msg(sb, KERN_ERR, "%s option not supported", opt);
1484 	} else if (token == Opt_commit) {
1485 		if (arg == 0)
1486 			arg = JBD2_DEFAULT_MAX_COMMIT_AGE;
1487 		sbi->s_commit_interval = HZ * arg;
1488 	} else if (token == Opt_max_batch_time) {
1489 		if (arg == 0)
1490 			arg = EXT4_DEF_MAX_BATCH_TIME;
1491 		sbi->s_max_batch_time = arg;
1492 	} else if (token == Opt_min_batch_time) {
1493 		sbi->s_min_batch_time = arg;
1494 	} else if (token == Opt_inode_readahead_blks) {
1495 		if (arg && (arg > (1 << 30) || !is_power_of_2(arg))) {
1496 			ext4_msg(sb, KERN_ERR,
1497 				 "EXT4-fs: inode_readahead_blks must be "
1498 				 "0 or a power of 2 smaller than 2^31");
1499 			return -1;
1500 		}
1501 		sbi->s_inode_readahead_blks = arg;
1502 	} else if (token == Opt_init_itable) {
1503 		set_opt(sb, INIT_INODE_TABLE);
1504 		if (!args->from)
1505 			arg = EXT4_DEF_LI_WAIT_MULT;
1506 		sbi->s_li_wait_mult = arg;
1507 	} else if (token == Opt_max_dir_size_kb) {
1508 		sbi->s_max_dir_size_kb = arg;
1509 	} else if (token == Opt_stripe) {
1510 		sbi->s_stripe = arg;
1511 	} else if (token == Opt_resuid) {
1512 		uid = make_kuid(current_user_ns(), arg);
1513 		if (!uid_valid(uid)) {
1514 			ext4_msg(sb, KERN_ERR, "Invalid uid value %d", arg);
1515 			return -1;
1516 		}
1517 		sbi->s_resuid = uid;
1518 	} else if (token == Opt_resgid) {
1519 		gid = make_kgid(current_user_ns(), arg);
1520 		if (!gid_valid(gid)) {
1521 			ext4_msg(sb, KERN_ERR, "Invalid gid value %d", arg);
1522 			return -1;
1523 		}
1524 		sbi->s_resgid = gid;
1525 	} else if (token == Opt_journal_dev) {
1526 		if (is_remount) {
1527 			ext4_msg(sb, KERN_ERR,
1528 				 "Cannot specify journal on remount");
1529 			return -1;
1530 		}
1531 		*journal_devnum = arg;
1532 	} else if (token == Opt_journal_ioprio) {
1533 		if (arg > 7) {
1534 			ext4_msg(sb, KERN_ERR, "Invalid journal IO priority"
1535 				 " (must be 0-7)");
1536 			return -1;
1537 		}
1538 		*journal_ioprio =
1539 			IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, arg);
1540 	} else if (m->flags & MOPT_DATAJ) {
1541 		if (is_remount) {
1542 			if (!sbi->s_journal)
1543 				ext4_msg(sb, KERN_WARNING, "Remounting file system with no journal so ignoring journalled data option");
1544 			else if (test_opt(sb, DATA_FLAGS) != m->mount_opt) {
1545 				ext4_msg(sb, KERN_ERR,
1546 					 "Cannot change data mode on remount");
1547 				return -1;
1548 			}
1549 		} else {
1550 			clear_opt(sb, DATA_FLAGS);
1551 			sbi->s_mount_opt |= m->mount_opt;
1552 		}
1553 #ifdef CONFIG_QUOTA
1554 	} else if (m->flags & MOPT_QFMT) {
1555 		if (sb_any_quota_loaded(sb) &&
1556 		    sbi->s_jquota_fmt != m->mount_opt) {
1557 			ext4_msg(sb, KERN_ERR, "Cannot change journaled "
1558 				 "quota options when quota turned on");
1559 			return -1;
1560 		}
1561 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
1562 					       EXT4_FEATURE_RO_COMPAT_QUOTA)) {
1563 			ext4_msg(sb, KERN_ERR,
1564 				 "Cannot set journaled quota options "
1565 				 "when QUOTA feature is enabled");
1566 			return -1;
1567 		}
1568 		sbi->s_jquota_fmt = m->mount_opt;
1569 #endif
1570 	} else {
1571 		if (!args->from)
1572 			arg = 1;
1573 		if (m->flags & MOPT_CLEAR)
1574 			arg = !arg;
1575 		else if (unlikely(!(m->flags & MOPT_SET))) {
1576 			ext4_msg(sb, KERN_WARNING,
1577 				 "buggy handling of option %s", opt);
1578 			WARN_ON(1);
1579 			return -1;
1580 		}
1581 		if (arg != 0)
1582 			sbi->s_mount_opt |= m->mount_opt;
1583 		else
1584 			sbi->s_mount_opt &= ~m->mount_opt;
1585 	}
1586 	return 1;
1587 }
1588 
1589 static int parse_options(char *options, struct super_block *sb,
1590 			 unsigned long *journal_devnum,
1591 			 unsigned int *journal_ioprio,
1592 			 int is_remount)
1593 {
1594 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1595 	char *p;
1596 	substring_t args[MAX_OPT_ARGS];
1597 	int token;
1598 
1599 	if (!options)
1600 		return 1;
1601 
1602 	while ((p = strsep(&options, ",")) != NULL) {
1603 		if (!*p)
1604 			continue;
1605 		/*
1606 		 * Initialize args struct so we know whether arg was
1607 		 * found; some options take optional arguments.
1608 		 */
1609 		args[0].to = args[0].from = NULL;
1610 		token = match_token(p, tokens, args);
1611 		if (handle_mount_opt(sb, p, token, args, journal_devnum,
1612 				     journal_ioprio, is_remount) < 0)
1613 			return 0;
1614 	}
1615 #ifdef CONFIG_QUOTA
1616 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA) &&
1617 	    (test_opt(sb, USRQUOTA) || test_opt(sb, GRPQUOTA))) {
1618 		ext4_msg(sb, KERN_ERR, "Cannot set quota options when QUOTA "
1619 			 "feature is enabled");
1620 		return 0;
1621 	}
1622 	if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
1623 		if (test_opt(sb, USRQUOTA) && sbi->s_qf_names[USRQUOTA])
1624 			clear_opt(sb, USRQUOTA);
1625 
1626 		if (test_opt(sb, GRPQUOTA) && sbi->s_qf_names[GRPQUOTA])
1627 			clear_opt(sb, GRPQUOTA);
1628 
1629 		if (test_opt(sb, GRPQUOTA) || test_opt(sb, USRQUOTA)) {
1630 			ext4_msg(sb, KERN_ERR, "old and new quota "
1631 					"format mixing");
1632 			return 0;
1633 		}
1634 
1635 		if (!sbi->s_jquota_fmt) {
1636 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1637 					"not specified");
1638 			return 0;
1639 		}
1640 	} else {
1641 		if (sbi->s_jquota_fmt) {
1642 			ext4_msg(sb, KERN_ERR, "journaled quota format "
1643 					"specified with no journaling "
1644 					"enabled");
1645 			return 0;
1646 		}
1647 	}
1648 #endif
1649 	if (test_opt(sb, DIOREAD_NOLOCK)) {
1650 		int blocksize =
1651 			BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
1652 
1653 		if (blocksize < PAGE_CACHE_SIZE) {
1654 			ext4_msg(sb, KERN_ERR, "can't mount with "
1655 				 "dioread_nolock if block size != PAGE_SIZE");
1656 			return 0;
1657 		}
1658 	}
1659 	return 1;
1660 }
1661 
1662 static inline void ext4_show_quota_options(struct seq_file *seq,
1663 					   struct super_block *sb)
1664 {
1665 #if defined(CONFIG_QUOTA)
1666 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1667 
1668 	if (sbi->s_jquota_fmt) {
1669 		char *fmtname = "";
1670 
1671 		switch (sbi->s_jquota_fmt) {
1672 		case QFMT_VFS_OLD:
1673 			fmtname = "vfsold";
1674 			break;
1675 		case QFMT_VFS_V0:
1676 			fmtname = "vfsv0";
1677 			break;
1678 		case QFMT_VFS_V1:
1679 			fmtname = "vfsv1";
1680 			break;
1681 		}
1682 		seq_printf(seq, ",jqfmt=%s", fmtname);
1683 	}
1684 
1685 	if (sbi->s_qf_names[USRQUOTA])
1686 		seq_printf(seq, ",usrjquota=%s", sbi->s_qf_names[USRQUOTA]);
1687 
1688 	if (sbi->s_qf_names[GRPQUOTA])
1689 		seq_printf(seq, ",grpjquota=%s", sbi->s_qf_names[GRPQUOTA]);
1690 
1691 	if (test_opt(sb, USRQUOTA))
1692 		seq_puts(seq, ",usrquota");
1693 
1694 	if (test_opt(sb, GRPQUOTA))
1695 		seq_puts(seq, ",grpquota");
1696 #endif
1697 }
1698 
1699 static const char *token2str(int token)
1700 {
1701 	const struct match_token *t;
1702 
1703 	for (t = tokens; t->token != Opt_err; t++)
1704 		if (t->token == token && !strchr(t->pattern, '='))
1705 			break;
1706 	return t->pattern;
1707 }
1708 
1709 /*
1710  * Show an option if
1711  *  - it's set to a non-default value OR
1712  *  - if the per-sb default is different from the global default
1713  */
1714 static int _ext4_show_options(struct seq_file *seq, struct super_block *sb,
1715 			      int nodefs)
1716 {
1717 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1718 	struct ext4_super_block *es = sbi->s_es;
1719 	int def_errors, def_mount_opt = nodefs ? 0 : sbi->s_def_mount_opt;
1720 	const struct mount_opts *m;
1721 	char sep = nodefs ? '\n' : ',';
1722 
1723 #define SEQ_OPTS_PUTS(str) seq_printf(seq, "%c" str, sep)
1724 #define SEQ_OPTS_PRINT(str, arg) seq_printf(seq, "%c" str, sep, arg)
1725 
1726 	if (sbi->s_sb_block != 1)
1727 		SEQ_OPTS_PRINT("sb=%llu", sbi->s_sb_block);
1728 
1729 	for (m = ext4_mount_opts; m->token != Opt_err; m++) {
1730 		int want_set = m->flags & MOPT_SET;
1731 		if (((m->flags & (MOPT_SET|MOPT_CLEAR)) == 0) ||
1732 		    (m->flags & MOPT_CLEAR_ERR))
1733 			continue;
1734 		if (!(m->mount_opt & (sbi->s_mount_opt ^ def_mount_opt)))
1735 			continue; /* skip if same as the default */
1736 		if ((want_set &&
1737 		     (sbi->s_mount_opt & m->mount_opt) != m->mount_opt) ||
1738 		    (!want_set && (sbi->s_mount_opt & m->mount_opt)))
1739 			continue; /* select Opt_noFoo vs Opt_Foo */
1740 		SEQ_OPTS_PRINT("%s", token2str(m->token));
1741 	}
1742 
1743 	if (nodefs || !uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT4_DEF_RESUID)) ||
1744 	    le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID)
1745 		SEQ_OPTS_PRINT("resuid=%u",
1746 				from_kuid_munged(&init_user_ns, sbi->s_resuid));
1747 	if (nodefs || !gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT4_DEF_RESGID)) ||
1748 	    le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID)
1749 		SEQ_OPTS_PRINT("resgid=%u",
1750 				from_kgid_munged(&init_user_ns, sbi->s_resgid));
1751 	def_errors = nodefs ? -1 : le16_to_cpu(es->s_errors);
1752 	if (test_opt(sb, ERRORS_RO) && def_errors != EXT4_ERRORS_RO)
1753 		SEQ_OPTS_PUTS("errors=remount-ro");
1754 	if (test_opt(sb, ERRORS_CONT) && def_errors != EXT4_ERRORS_CONTINUE)
1755 		SEQ_OPTS_PUTS("errors=continue");
1756 	if (test_opt(sb, ERRORS_PANIC) && def_errors != EXT4_ERRORS_PANIC)
1757 		SEQ_OPTS_PUTS("errors=panic");
1758 	if (nodefs || sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ)
1759 		SEQ_OPTS_PRINT("commit=%lu", sbi->s_commit_interval / HZ);
1760 	if (nodefs || sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME)
1761 		SEQ_OPTS_PRINT("min_batch_time=%u", sbi->s_min_batch_time);
1762 	if (nodefs || sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME)
1763 		SEQ_OPTS_PRINT("max_batch_time=%u", sbi->s_max_batch_time);
1764 	if (sb->s_flags & MS_I_VERSION)
1765 		SEQ_OPTS_PUTS("i_version");
1766 	if (nodefs || sbi->s_stripe)
1767 		SEQ_OPTS_PRINT("stripe=%lu", sbi->s_stripe);
1768 	if (EXT4_MOUNT_DATA_FLAGS & (sbi->s_mount_opt ^ def_mount_opt)) {
1769 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
1770 			SEQ_OPTS_PUTS("data=journal");
1771 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
1772 			SEQ_OPTS_PUTS("data=ordered");
1773 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
1774 			SEQ_OPTS_PUTS("data=writeback");
1775 	}
1776 	if (nodefs ||
1777 	    sbi->s_inode_readahead_blks != EXT4_DEF_INODE_READAHEAD_BLKS)
1778 		SEQ_OPTS_PRINT("inode_readahead_blks=%u",
1779 			       sbi->s_inode_readahead_blks);
1780 
1781 	if (nodefs || (test_opt(sb, INIT_INODE_TABLE) &&
1782 		       (sbi->s_li_wait_mult != EXT4_DEF_LI_WAIT_MULT)))
1783 		SEQ_OPTS_PRINT("init_itable=%u", sbi->s_li_wait_mult);
1784 	if (nodefs || sbi->s_max_dir_size_kb)
1785 		SEQ_OPTS_PRINT("max_dir_size_kb=%u", sbi->s_max_dir_size_kb);
1786 
1787 	ext4_show_quota_options(seq, sb);
1788 	return 0;
1789 }
1790 
1791 static int ext4_show_options(struct seq_file *seq, struct dentry *root)
1792 {
1793 	return _ext4_show_options(seq, root->d_sb, 0);
1794 }
1795 
1796 static int options_seq_show(struct seq_file *seq, void *offset)
1797 {
1798 	struct super_block *sb = seq->private;
1799 	int rc;
1800 
1801 	seq_puts(seq, (sb->s_flags & MS_RDONLY) ? "ro" : "rw");
1802 	rc = _ext4_show_options(seq, sb, 1);
1803 	seq_puts(seq, "\n");
1804 	return rc;
1805 }
1806 
1807 static int options_open_fs(struct inode *inode, struct file *file)
1808 {
1809 	return single_open(file, options_seq_show, PDE_DATA(inode));
1810 }
1811 
1812 static const struct file_operations ext4_seq_options_fops = {
1813 	.owner = THIS_MODULE,
1814 	.open = options_open_fs,
1815 	.read = seq_read,
1816 	.llseek = seq_lseek,
1817 	.release = single_release,
1818 };
1819 
1820 static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
1821 			    int read_only)
1822 {
1823 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1824 	int res = 0;
1825 
1826 	if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
1827 		ext4_msg(sb, KERN_ERR, "revision level too high, "
1828 			 "forcing read-only mode");
1829 		res = MS_RDONLY;
1830 	}
1831 	if (read_only)
1832 		goto done;
1833 	if (!(sbi->s_mount_state & EXT4_VALID_FS))
1834 		ext4_msg(sb, KERN_WARNING, "warning: mounting unchecked fs, "
1835 			 "running e2fsck is recommended");
1836 	else if ((sbi->s_mount_state & EXT4_ERROR_FS))
1837 		ext4_msg(sb, KERN_WARNING,
1838 			 "warning: mounting fs with errors, "
1839 			 "running e2fsck is recommended");
1840 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) > 0 &&
1841 		 le16_to_cpu(es->s_mnt_count) >=
1842 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
1843 		ext4_msg(sb, KERN_WARNING,
1844 			 "warning: maximal mount count reached, "
1845 			 "running e2fsck is recommended");
1846 	else if (le32_to_cpu(es->s_checkinterval) &&
1847 		(le32_to_cpu(es->s_lastcheck) +
1848 			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
1849 		ext4_msg(sb, KERN_WARNING,
1850 			 "warning: checktime reached, "
1851 			 "running e2fsck is recommended");
1852 	if (!sbi->s_journal)
1853 		es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1854 	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
1855 		es->s_max_mnt_count = cpu_to_le16(EXT4_DFL_MAX_MNT_COUNT);
1856 	le16_add_cpu(&es->s_mnt_count, 1);
1857 	es->s_mtime = cpu_to_le32(get_seconds());
1858 	ext4_update_dynamic_rev(sb);
1859 	if (sbi->s_journal)
1860 		EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
1861 
1862 	ext4_commit_super(sb, 1);
1863 done:
1864 	if (test_opt(sb, DEBUG))
1865 		printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, "
1866 				"bpg=%lu, ipg=%lu, mo=%04x, mo2=%04x]\n",
1867 			sb->s_blocksize,
1868 			sbi->s_groups_count,
1869 			EXT4_BLOCKS_PER_GROUP(sb),
1870 			EXT4_INODES_PER_GROUP(sb),
1871 			sbi->s_mount_opt, sbi->s_mount_opt2);
1872 
1873 	cleancache_init_fs(sb);
1874 	return res;
1875 }
1876 
1877 int ext4_alloc_flex_bg_array(struct super_block *sb, ext4_group_t ngroup)
1878 {
1879 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1880 	struct flex_groups *new_groups;
1881 	int size;
1882 
1883 	if (!sbi->s_log_groups_per_flex)
1884 		return 0;
1885 
1886 	size = ext4_flex_group(sbi, ngroup - 1) + 1;
1887 	if (size <= sbi->s_flex_groups_allocated)
1888 		return 0;
1889 
1890 	size = roundup_pow_of_two(size * sizeof(struct flex_groups));
1891 	new_groups = ext4_kvzalloc(size, GFP_KERNEL);
1892 	if (!new_groups) {
1893 		ext4_msg(sb, KERN_ERR, "not enough memory for %d flex groups",
1894 			 size / (int) sizeof(struct flex_groups));
1895 		return -ENOMEM;
1896 	}
1897 
1898 	if (sbi->s_flex_groups) {
1899 		memcpy(new_groups, sbi->s_flex_groups,
1900 		       (sbi->s_flex_groups_allocated *
1901 			sizeof(struct flex_groups)));
1902 		ext4_kvfree(sbi->s_flex_groups);
1903 	}
1904 	sbi->s_flex_groups = new_groups;
1905 	sbi->s_flex_groups_allocated = size / sizeof(struct flex_groups);
1906 	return 0;
1907 }
1908 
1909 static int ext4_fill_flex_info(struct super_block *sb)
1910 {
1911 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1912 	struct ext4_group_desc *gdp = NULL;
1913 	ext4_group_t flex_group;
1914 	unsigned int groups_per_flex = 0;
1915 	int i, err;
1916 
1917 	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
1918 	if (sbi->s_log_groups_per_flex < 1 || sbi->s_log_groups_per_flex > 31) {
1919 		sbi->s_log_groups_per_flex = 0;
1920 		return 1;
1921 	}
1922 	groups_per_flex = 1U << sbi->s_log_groups_per_flex;
1923 
1924 	err = ext4_alloc_flex_bg_array(sb, sbi->s_groups_count);
1925 	if (err)
1926 		goto failed;
1927 
1928 	for (i = 0; i < sbi->s_groups_count; i++) {
1929 		gdp = ext4_get_group_desc(sb, i, NULL);
1930 
1931 		flex_group = ext4_flex_group(sbi, i);
1932 		atomic_add(ext4_free_inodes_count(sb, gdp),
1933 			   &sbi->s_flex_groups[flex_group].free_inodes);
1934 		atomic64_add(ext4_free_group_clusters(sb, gdp),
1935 			     &sbi->s_flex_groups[flex_group].free_clusters);
1936 		atomic_add(ext4_used_dirs_count(sb, gdp),
1937 			   &sbi->s_flex_groups[flex_group].used_dirs);
1938 	}
1939 
1940 	return 1;
1941 failed:
1942 	return 0;
1943 }
1944 
1945 static __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
1946 				   struct ext4_group_desc *gdp)
1947 {
1948 	int offset;
1949 	__u16 crc = 0;
1950 	__le32 le_group = cpu_to_le32(block_group);
1951 
1952 	if ((sbi->s_es->s_feature_ro_compat &
1953 	     cpu_to_le32(EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))) {
1954 		/* Use new metadata_csum algorithm */
1955 		__le16 save_csum;
1956 		__u32 csum32;
1957 
1958 		save_csum = gdp->bg_checksum;
1959 		gdp->bg_checksum = 0;
1960 		csum32 = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&le_group,
1961 				     sizeof(le_group));
1962 		csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp,
1963 				     sbi->s_desc_size);
1964 		gdp->bg_checksum = save_csum;
1965 
1966 		crc = csum32 & 0xFFFF;
1967 		goto out;
1968 	}
1969 
1970 	/* old crc16 code */
1971 	offset = offsetof(struct ext4_group_desc, bg_checksum);
1972 
1973 	crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
1974 	crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
1975 	crc = crc16(crc, (__u8 *)gdp, offset);
1976 	offset += sizeof(gdp->bg_checksum); /* skip checksum */
1977 	/* for checksum of struct ext4_group_desc do the rest...*/
1978 	if ((sbi->s_es->s_feature_incompat &
1979 	     cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) &&
1980 	    offset < le16_to_cpu(sbi->s_es->s_desc_size))
1981 		crc = crc16(crc, (__u8 *)gdp + offset,
1982 			    le16_to_cpu(sbi->s_es->s_desc_size) -
1983 				offset);
1984 
1985 out:
1986 	return cpu_to_le16(crc);
1987 }
1988 
1989 int ext4_group_desc_csum_verify(struct super_block *sb, __u32 block_group,
1990 				struct ext4_group_desc *gdp)
1991 {
1992 	if (ext4_has_group_desc_csum(sb) &&
1993 	    (gdp->bg_checksum != ext4_group_desc_csum(EXT4_SB(sb),
1994 						      block_group, gdp)))
1995 		return 0;
1996 
1997 	return 1;
1998 }
1999 
2000 void ext4_group_desc_csum_set(struct super_block *sb, __u32 block_group,
2001 			      struct ext4_group_desc *gdp)
2002 {
2003 	if (!ext4_has_group_desc_csum(sb))
2004 		return;
2005 	gdp->bg_checksum = ext4_group_desc_csum(EXT4_SB(sb), block_group, gdp);
2006 }
2007 
2008 /* Called at mount-time, super-block is locked */
2009 static int ext4_check_descriptors(struct super_block *sb,
2010 				  ext4_group_t *first_not_zeroed)
2011 {
2012 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2013 	ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
2014 	ext4_fsblk_t last_block;
2015 	ext4_fsblk_t block_bitmap;
2016 	ext4_fsblk_t inode_bitmap;
2017 	ext4_fsblk_t inode_table;
2018 	int flexbg_flag = 0;
2019 	ext4_group_t i, grp = sbi->s_groups_count;
2020 
2021 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
2022 		flexbg_flag = 1;
2023 
2024 	ext4_debug("Checking group descriptors");
2025 
2026 	for (i = 0; i < sbi->s_groups_count; i++) {
2027 		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
2028 
2029 		if (i == sbi->s_groups_count - 1 || flexbg_flag)
2030 			last_block = ext4_blocks_count(sbi->s_es) - 1;
2031 		else
2032 			last_block = first_block +
2033 				(EXT4_BLOCKS_PER_GROUP(sb) - 1);
2034 
2035 		if ((grp == sbi->s_groups_count) &&
2036 		   !(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2037 			grp = i;
2038 
2039 		block_bitmap = ext4_block_bitmap(sb, gdp);
2040 		if (block_bitmap < first_block || block_bitmap > last_block) {
2041 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2042 			       "Block bitmap for group %u not in group "
2043 			       "(block %llu)!", i, block_bitmap);
2044 			return 0;
2045 		}
2046 		inode_bitmap = ext4_inode_bitmap(sb, gdp);
2047 		if (inode_bitmap < first_block || inode_bitmap > last_block) {
2048 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2049 			       "Inode bitmap for group %u not in group "
2050 			       "(block %llu)!", i, inode_bitmap);
2051 			return 0;
2052 		}
2053 		inode_table = ext4_inode_table(sb, gdp);
2054 		if (inode_table < first_block ||
2055 		    inode_table + sbi->s_itb_per_group - 1 > last_block) {
2056 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2057 			       "Inode table for group %u not in group "
2058 			       "(block %llu)!", i, inode_table);
2059 			return 0;
2060 		}
2061 		ext4_lock_group(sb, i);
2062 		if (!ext4_group_desc_csum_verify(sb, i, gdp)) {
2063 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
2064 				 "Checksum for group %u failed (%u!=%u)",
2065 				 i, le16_to_cpu(ext4_group_desc_csum(sbi, i,
2066 				     gdp)), le16_to_cpu(gdp->bg_checksum));
2067 			if (!(sb->s_flags & MS_RDONLY)) {
2068 				ext4_unlock_group(sb, i);
2069 				return 0;
2070 			}
2071 		}
2072 		ext4_unlock_group(sb, i);
2073 		if (!flexbg_flag)
2074 			first_block += EXT4_BLOCKS_PER_GROUP(sb);
2075 	}
2076 	if (NULL != first_not_zeroed)
2077 		*first_not_zeroed = grp;
2078 
2079 	ext4_free_blocks_count_set(sbi->s_es,
2080 				   EXT4_C2B(sbi, ext4_count_free_clusters(sb)));
2081 	sbi->s_es->s_free_inodes_count =cpu_to_le32(ext4_count_free_inodes(sb));
2082 	return 1;
2083 }
2084 
2085 /* ext4_orphan_cleanup() walks a singly-linked list of inodes (starting at
2086  * the superblock) which were deleted from all directories, but held open by
2087  * a process at the time of a crash.  We walk the list and try to delete these
2088  * inodes at recovery time (only with a read-write filesystem).
2089  *
2090  * In order to keep the orphan inode chain consistent during traversal (in
2091  * case of crash during recovery), we link each inode into the superblock
2092  * orphan list_head and handle it the same way as an inode deletion during
2093  * normal operation (which journals the operations for us).
2094  *
2095  * We only do an iget() and an iput() on each inode, which is very safe if we
2096  * accidentally point at an in-use or already deleted inode.  The worst that
2097  * can happen in this case is that we get a "bit already cleared" message from
2098  * ext4_free_inode().  The only reason we would point at a wrong inode is if
2099  * e2fsck was run on this filesystem, and it must have already done the orphan
2100  * inode cleanup for us, so we can safely abort without any further action.
2101  */
2102 static void ext4_orphan_cleanup(struct super_block *sb,
2103 				struct ext4_super_block *es)
2104 {
2105 	unsigned int s_flags = sb->s_flags;
2106 	int nr_orphans = 0, nr_truncates = 0;
2107 #ifdef CONFIG_QUOTA
2108 	int i;
2109 #endif
2110 	if (!es->s_last_orphan) {
2111 		jbd_debug(4, "no orphan inodes to clean up\n");
2112 		return;
2113 	}
2114 
2115 	if (bdev_read_only(sb->s_bdev)) {
2116 		ext4_msg(sb, KERN_ERR, "write access "
2117 			"unavailable, skipping orphan cleanup");
2118 		return;
2119 	}
2120 
2121 	/* Check if feature set would not allow a r/w mount */
2122 	if (!ext4_feature_set_ok(sb, 0)) {
2123 		ext4_msg(sb, KERN_INFO, "Skipping orphan cleanup due to "
2124 			 "unknown ROCOMPAT features");
2125 		return;
2126 	}
2127 
2128 	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
2129 		/* don't clear list on RO mount w/ errors */
2130 		if (es->s_last_orphan && !(s_flags & MS_RDONLY)) {
2131 			jbd_debug(1, "Errors on filesystem, "
2132 				  "clearing orphan list.\n");
2133 			es->s_last_orphan = 0;
2134 		}
2135 		jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
2136 		return;
2137 	}
2138 
2139 	if (s_flags & MS_RDONLY) {
2140 		ext4_msg(sb, KERN_INFO, "orphan cleanup on readonly fs");
2141 		sb->s_flags &= ~MS_RDONLY;
2142 	}
2143 #ifdef CONFIG_QUOTA
2144 	/* Needed for iput() to work correctly and not trash data */
2145 	sb->s_flags |= MS_ACTIVE;
2146 	/* Turn on quotas so that they are updated correctly */
2147 	for (i = 0; i < MAXQUOTAS; i++) {
2148 		if (EXT4_SB(sb)->s_qf_names[i]) {
2149 			int ret = ext4_quota_on_mount(sb, i);
2150 			if (ret < 0)
2151 				ext4_msg(sb, KERN_ERR,
2152 					"Cannot turn on journaled "
2153 					"quota: error %d", ret);
2154 		}
2155 	}
2156 #endif
2157 
2158 	while (es->s_last_orphan) {
2159 		struct inode *inode;
2160 
2161 		inode = ext4_orphan_get(sb, le32_to_cpu(es->s_last_orphan));
2162 		if (IS_ERR(inode)) {
2163 			es->s_last_orphan = 0;
2164 			break;
2165 		}
2166 
2167 		list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
2168 		dquot_initialize(inode);
2169 		if (inode->i_nlink) {
2170 			ext4_msg(sb, KERN_DEBUG,
2171 				"%s: truncating inode %lu to %lld bytes",
2172 				__func__, inode->i_ino, inode->i_size);
2173 			jbd_debug(2, "truncating inode %lu to %lld bytes\n",
2174 				  inode->i_ino, inode->i_size);
2175 			mutex_lock(&inode->i_mutex);
2176 			ext4_truncate(inode);
2177 			mutex_unlock(&inode->i_mutex);
2178 			nr_truncates++;
2179 		} else {
2180 			ext4_msg(sb, KERN_DEBUG,
2181 				"%s: deleting unreferenced inode %lu",
2182 				__func__, inode->i_ino);
2183 			jbd_debug(2, "deleting unreferenced inode %lu\n",
2184 				  inode->i_ino);
2185 			nr_orphans++;
2186 		}
2187 		iput(inode);  /* The delete magic happens here! */
2188 	}
2189 
2190 #define PLURAL(x) (x), ((x) == 1) ? "" : "s"
2191 
2192 	if (nr_orphans)
2193 		ext4_msg(sb, KERN_INFO, "%d orphan inode%s deleted",
2194 		       PLURAL(nr_orphans));
2195 	if (nr_truncates)
2196 		ext4_msg(sb, KERN_INFO, "%d truncate%s cleaned up",
2197 		       PLURAL(nr_truncates));
2198 #ifdef CONFIG_QUOTA
2199 	/* Turn quotas off */
2200 	for (i = 0; i < MAXQUOTAS; i++) {
2201 		if (sb_dqopt(sb)->files[i])
2202 			dquot_quota_off(sb, i);
2203 	}
2204 #endif
2205 	sb->s_flags = s_flags; /* Restore MS_RDONLY status */
2206 }
2207 
2208 /*
2209  * Maximal extent format file size.
2210  * Resulting logical blkno at s_maxbytes must fit in our on-disk
2211  * extent format containers, within a sector_t, and within i_blocks
2212  * in the vfs.  ext4 inode has 48 bits of i_block in fsblock units,
2213  * so that won't be a limiting factor.
2214  *
2215  * However there is other limiting factor. We do store extents in the form
2216  * of starting block and length, hence the resulting length of the extent
2217  * covering maximum file size must fit into on-disk format containers as
2218  * well. Given that length is always by 1 unit bigger than max unit (because
2219  * we count 0 as well) we have to lower the s_maxbytes by one fs block.
2220  *
2221  * Note, this does *not* consider any metadata overhead for vfs i_blocks.
2222  */
2223 static loff_t ext4_max_size(int blkbits, int has_huge_files)
2224 {
2225 	loff_t res;
2226 	loff_t upper_limit = MAX_LFS_FILESIZE;
2227 
2228 	/* small i_blocks in vfs inode? */
2229 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2230 		/*
2231 		 * CONFIG_LBDAF is not enabled implies the inode
2232 		 * i_block represent total blocks in 512 bytes
2233 		 * 32 == size of vfs inode i_blocks * 8
2234 		 */
2235 		upper_limit = (1LL << 32) - 1;
2236 
2237 		/* total blocks in file system block size */
2238 		upper_limit >>= (blkbits - 9);
2239 		upper_limit <<= blkbits;
2240 	}
2241 
2242 	/*
2243 	 * 32-bit extent-start container, ee_block. We lower the maxbytes
2244 	 * by one fs block, so ee_len can cover the extent of maximum file
2245 	 * size
2246 	 */
2247 	res = (1LL << 32) - 1;
2248 	res <<= blkbits;
2249 
2250 	/* Sanity check against vm- & vfs- imposed limits */
2251 	if (res > upper_limit)
2252 		res = upper_limit;
2253 
2254 	return res;
2255 }
2256 
2257 /*
2258  * Maximal bitmap file size.  There is a direct, and {,double-,triple-}indirect
2259  * block limit, and also a limit of (2^48 - 1) 512-byte sectors in i_blocks.
2260  * We need to be 1 filesystem block less than the 2^48 sector limit.
2261  */
2262 static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
2263 {
2264 	loff_t res = EXT4_NDIR_BLOCKS;
2265 	int meta_blocks;
2266 	loff_t upper_limit;
2267 	/* This is calculated to be the largest file size for a dense, block
2268 	 * mapped file such that the file's total number of 512-byte sectors,
2269 	 * including data and all indirect blocks, does not exceed (2^48 - 1).
2270 	 *
2271 	 * __u32 i_blocks_lo and _u16 i_blocks_high represent the total
2272 	 * number of 512-byte sectors of the file.
2273 	 */
2274 
2275 	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
2276 		/*
2277 		 * !has_huge_files or CONFIG_LBDAF not enabled implies that
2278 		 * the inode i_block field represents total file blocks in
2279 		 * 2^32 512-byte sectors == size of vfs inode i_blocks * 8
2280 		 */
2281 		upper_limit = (1LL << 32) - 1;
2282 
2283 		/* total blocks in file system block size */
2284 		upper_limit >>= (bits - 9);
2285 
2286 	} else {
2287 		/*
2288 		 * We use 48 bit ext4_inode i_blocks
2289 		 * With EXT4_HUGE_FILE_FL set the i_blocks
2290 		 * represent total number of blocks in
2291 		 * file system block size
2292 		 */
2293 		upper_limit = (1LL << 48) - 1;
2294 
2295 	}
2296 
2297 	/* indirect blocks */
2298 	meta_blocks = 1;
2299 	/* double indirect blocks */
2300 	meta_blocks += 1 + (1LL << (bits-2));
2301 	/* tripple indirect blocks */
2302 	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
2303 
2304 	upper_limit -= meta_blocks;
2305 	upper_limit <<= bits;
2306 
2307 	res += 1LL << (bits-2);
2308 	res += 1LL << (2*(bits-2));
2309 	res += 1LL << (3*(bits-2));
2310 	res <<= bits;
2311 	if (res > upper_limit)
2312 		res = upper_limit;
2313 
2314 	if (res > MAX_LFS_FILESIZE)
2315 		res = MAX_LFS_FILESIZE;
2316 
2317 	return res;
2318 }
2319 
2320 static ext4_fsblk_t descriptor_loc(struct super_block *sb,
2321 				   ext4_fsblk_t logical_sb_block, int nr)
2322 {
2323 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2324 	ext4_group_t bg, first_meta_bg;
2325 	int has_super = 0;
2326 
2327 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
2328 
2329 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
2330 	    nr < first_meta_bg)
2331 		return logical_sb_block + nr + 1;
2332 	bg = sbi->s_desc_per_block * nr;
2333 	if (ext4_bg_has_super(sb, bg))
2334 		has_super = 1;
2335 
2336 	return (has_super + ext4_group_first_block_no(sb, bg));
2337 }
2338 
2339 /**
2340  * ext4_get_stripe_size: Get the stripe size.
2341  * @sbi: In memory super block info
2342  *
2343  * If we have specified it via mount option, then
2344  * use the mount option value. If the value specified at mount time is
2345  * greater than the blocks per group use the super block value.
2346  * If the super block value is greater than blocks per group return 0.
2347  * Allocator needs it be less than blocks per group.
2348  *
2349  */
2350 static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi)
2351 {
2352 	unsigned long stride = le16_to_cpu(sbi->s_es->s_raid_stride);
2353 	unsigned long stripe_width =
2354 			le32_to_cpu(sbi->s_es->s_raid_stripe_width);
2355 	int ret;
2356 
2357 	if (sbi->s_stripe && sbi->s_stripe <= sbi->s_blocks_per_group)
2358 		ret = sbi->s_stripe;
2359 	else if (stripe_width <= sbi->s_blocks_per_group)
2360 		ret = stripe_width;
2361 	else if (stride <= sbi->s_blocks_per_group)
2362 		ret = stride;
2363 	else
2364 		ret = 0;
2365 
2366 	/*
2367 	 * If the stripe width is 1, this makes no sense and
2368 	 * we set it to 0 to turn off stripe handling code.
2369 	 */
2370 	if (ret <= 1)
2371 		ret = 0;
2372 
2373 	return ret;
2374 }
2375 
2376 /* sysfs supprt */
2377 
2378 struct ext4_attr {
2379 	struct attribute attr;
2380 	ssize_t (*show)(struct ext4_attr *, struct ext4_sb_info *, char *);
2381 	ssize_t (*store)(struct ext4_attr *, struct ext4_sb_info *,
2382 			 const char *, size_t);
2383 	int offset;
2384 };
2385 
2386 static int parse_strtoull(const char *buf,
2387 		unsigned long long max, unsigned long long *value)
2388 {
2389 	int ret;
2390 
2391 	ret = kstrtoull(skip_spaces(buf), 0, value);
2392 	if (!ret && *value > max)
2393 		ret = -EINVAL;
2394 	return ret;
2395 }
2396 
2397 static ssize_t delayed_allocation_blocks_show(struct ext4_attr *a,
2398 					      struct ext4_sb_info *sbi,
2399 					      char *buf)
2400 {
2401 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2402 		(s64) EXT4_C2B(sbi,
2403 			percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
2404 }
2405 
2406 static ssize_t session_write_kbytes_show(struct ext4_attr *a,
2407 					 struct ext4_sb_info *sbi, char *buf)
2408 {
2409 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
2410 
2411 	if (!sb->s_bdev->bd_part)
2412 		return snprintf(buf, PAGE_SIZE, "0\n");
2413 	return snprintf(buf, PAGE_SIZE, "%lu\n",
2414 			(part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
2415 			 sbi->s_sectors_written_start) >> 1);
2416 }
2417 
2418 static ssize_t lifetime_write_kbytes_show(struct ext4_attr *a,
2419 					  struct ext4_sb_info *sbi, char *buf)
2420 {
2421 	struct super_block *sb = sbi->s_buddy_cache->i_sb;
2422 
2423 	if (!sb->s_bdev->bd_part)
2424 		return snprintf(buf, PAGE_SIZE, "0\n");
2425 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2426 			(unsigned long long)(sbi->s_kbytes_written +
2427 			((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
2428 			  EXT4_SB(sb)->s_sectors_written_start) >> 1)));
2429 }
2430 
2431 static ssize_t inode_readahead_blks_store(struct ext4_attr *a,
2432 					  struct ext4_sb_info *sbi,
2433 					  const char *buf, size_t count)
2434 {
2435 	unsigned long t;
2436 	int ret;
2437 
2438 	ret = kstrtoul(skip_spaces(buf), 0, &t);
2439 	if (ret)
2440 		return ret;
2441 
2442 	if (t && (!is_power_of_2(t) || t > 0x40000000))
2443 		return -EINVAL;
2444 
2445 	sbi->s_inode_readahead_blks = t;
2446 	return count;
2447 }
2448 
2449 static ssize_t sbi_ui_show(struct ext4_attr *a,
2450 			   struct ext4_sb_info *sbi, char *buf)
2451 {
2452 	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
2453 
2454 	return snprintf(buf, PAGE_SIZE, "%u\n", *ui);
2455 }
2456 
2457 static ssize_t sbi_ui_store(struct ext4_attr *a,
2458 			    struct ext4_sb_info *sbi,
2459 			    const char *buf, size_t count)
2460 {
2461 	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
2462 	unsigned long t;
2463 	int ret;
2464 
2465 	ret = kstrtoul(skip_spaces(buf), 0, &t);
2466 	if (ret)
2467 		return ret;
2468 	*ui = t;
2469 	return count;
2470 }
2471 
2472 static ssize_t reserved_clusters_show(struct ext4_attr *a,
2473 				  struct ext4_sb_info *sbi, char *buf)
2474 {
2475 	return snprintf(buf, PAGE_SIZE, "%llu\n",
2476 		(unsigned long long) atomic64_read(&sbi->s_resv_clusters));
2477 }
2478 
2479 static ssize_t reserved_clusters_store(struct ext4_attr *a,
2480 				   struct ext4_sb_info *sbi,
2481 				   const char *buf, size_t count)
2482 {
2483 	unsigned long long val;
2484 	int ret;
2485 
2486 	if (parse_strtoull(buf, -1ULL, &val))
2487 		return -EINVAL;
2488 	ret = ext4_reserve_clusters(sbi, val);
2489 
2490 	return ret ? ret : count;
2491 }
2492 
2493 static ssize_t trigger_test_error(struct ext4_attr *a,
2494 				  struct ext4_sb_info *sbi,
2495 				  const char *buf, size_t count)
2496 {
2497 	int len = count;
2498 
2499 	if (!capable(CAP_SYS_ADMIN))
2500 		return -EPERM;
2501 
2502 	if (len && buf[len-1] == '\n')
2503 		len--;
2504 
2505 	if (len)
2506 		ext4_error(sbi->s_sb, "%.*s", len, buf);
2507 	return count;
2508 }
2509 
2510 #define EXT4_ATTR_OFFSET(_name,_mode,_show,_store,_elname) \
2511 static struct ext4_attr ext4_attr_##_name = {			\
2512 	.attr = {.name = __stringify(_name), .mode = _mode },	\
2513 	.show	= _show,					\
2514 	.store	= _store,					\
2515 	.offset = offsetof(struct ext4_sb_info, _elname),	\
2516 }
2517 #define EXT4_ATTR(name, mode, show, store) \
2518 static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store)
2519 
2520 #define EXT4_INFO_ATTR(name) EXT4_ATTR(name, 0444, NULL, NULL)
2521 #define EXT4_RO_ATTR(name) EXT4_ATTR(name, 0444, name##_show, NULL)
2522 #define EXT4_RW_ATTR(name) EXT4_ATTR(name, 0644, name##_show, name##_store)
2523 #define EXT4_RW_ATTR_SBI_UI(name, elname)	\
2524 	EXT4_ATTR_OFFSET(name, 0644, sbi_ui_show, sbi_ui_store, elname)
2525 #define ATTR_LIST(name) &ext4_attr_##name.attr
2526 
2527 EXT4_RO_ATTR(delayed_allocation_blocks);
2528 EXT4_RO_ATTR(session_write_kbytes);
2529 EXT4_RO_ATTR(lifetime_write_kbytes);
2530 EXT4_RW_ATTR(reserved_clusters);
2531 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, sbi_ui_show,
2532 		 inode_readahead_blks_store, s_inode_readahead_blks);
2533 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
2534 EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
2535 EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
2536 EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
2537 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
2538 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
2539 EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
2540 EXT4_RW_ATTR_SBI_UI(max_writeback_mb_bump, s_max_writeback_mb_bump);
2541 EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
2542 EXT4_ATTR(trigger_fs_error, 0200, NULL, trigger_test_error);
2543 
2544 static struct attribute *ext4_attrs[] = {
2545 	ATTR_LIST(delayed_allocation_blocks),
2546 	ATTR_LIST(session_write_kbytes),
2547 	ATTR_LIST(lifetime_write_kbytes),
2548 	ATTR_LIST(reserved_clusters),
2549 	ATTR_LIST(inode_readahead_blks),
2550 	ATTR_LIST(inode_goal),
2551 	ATTR_LIST(mb_stats),
2552 	ATTR_LIST(mb_max_to_scan),
2553 	ATTR_LIST(mb_min_to_scan),
2554 	ATTR_LIST(mb_order2_req),
2555 	ATTR_LIST(mb_stream_req),
2556 	ATTR_LIST(mb_group_prealloc),
2557 	ATTR_LIST(max_writeback_mb_bump),
2558 	ATTR_LIST(extent_max_zeroout_kb),
2559 	ATTR_LIST(trigger_fs_error),
2560 	NULL,
2561 };
2562 
2563 /* Features this copy of ext4 supports */
2564 EXT4_INFO_ATTR(lazy_itable_init);
2565 EXT4_INFO_ATTR(batched_discard);
2566 EXT4_INFO_ATTR(meta_bg_resize);
2567 
2568 static struct attribute *ext4_feat_attrs[] = {
2569 	ATTR_LIST(lazy_itable_init),
2570 	ATTR_LIST(batched_discard),
2571 	ATTR_LIST(meta_bg_resize),
2572 	NULL,
2573 };
2574 
2575 static ssize_t ext4_attr_show(struct kobject *kobj,
2576 			      struct attribute *attr, char *buf)
2577 {
2578 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2579 						s_kobj);
2580 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
2581 
2582 	return a->show ? a->show(a, sbi, buf) : 0;
2583 }
2584 
2585 static ssize_t ext4_attr_store(struct kobject *kobj,
2586 			       struct attribute *attr,
2587 			       const char *buf, size_t len)
2588 {
2589 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2590 						s_kobj);
2591 	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
2592 
2593 	return a->store ? a->store(a, sbi, buf, len) : 0;
2594 }
2595 
2596 static void ext4_sb_release(struct kobject *kobj)
2597 {
2598 	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
2599 						s_kobj);
2600 	complete(&sbi->s_kobj_unregister);
2601 }
2602 
2603 static const struct sysfs_ops ext4_attr_ops = {
2604 	.show	= ext4_attr_show,
2605 	.store	= ext4_attr_store,
2606 };
2607 
2608 static struct kobj_type ext4_ktype = {
2609 	.default_attrs	= ext4_attrs,
2610 	.sysfs_ops	= &ext4_attr_ops,
2611 	.release	= ext4_sb_release,
2612 };
2613 
2614 static void ext4_feat_release(struct kobject *kobj)
2615 {
2616 	complete(&ext4_feat->f_kobj_unregister);
2617 }
2618 
2619 static struct kobj_type ext4_feat_ktype = {
2620 	.default_attrs	= ext4_feat_attrs,
2621 	.sysfs_ops	= &ext4_attr_ops,
2622 	.release	= ext4_feat_release,
2623 };
2624 
2625 /*
2626  * Check whether this filesystem can be mounted based on
2627  * the features present and the RDONLY/RDWR mount requested.
2628  * Returns 1 if this filesystem can be mounted as requested,
2629  * 0 if it cannot be.
2630  */
2631 static int ext4_feature_set_ok(struct super_block *sb, int readonly)
2632 {
2633 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT4_FEATURE_INCOMPAT_SUPP)) {
2634 		ext4_msg(sb, KERN_ERR,
2635 			"Couldn't mount because of "
2636 			"unsupported optional features (%x)",
2637 			(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_incompat) &
2638 			~EXT4_FEATURE_INCOMPAT_SUPP));
2639 		return 0;
2640 	}
2641 
2642 	if (readonly)
2643 		return 1;
2644 
2645 	/* Check that feature set is OK for a read-write mount */
2646 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT4_FEATURE_RO_COMPAT_SUPP)) {
2647 		ext4_msg(sb, KERN_ERR, "couldn't mount RDWR because of "
2648 			 "unsupported optional features (%x)",
2649 			 (le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_ro_compat) &
2650 				~EXT4_FEATURE_RO_COMPAT_SUPP));
2651 		return 0;
2652 	}
2653 	/*
2654 	 * Large file size enabled file system can only be mounted
2655 	 * read-write on 32-bit systems if kernel is built with CONFIG_LBDAF
2656 	 */
2657 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
2658 		if (sizeof(blkcnt_t) < sizeof(u64)) {
2659 			ext4_msg(sb, KERN_ERR, "Filesystem with huge files "
2660 				 "cannot be mounted RDWR without "
2661 				 "CONFIG_LBDAF");
2662 			return 0;
2663 		}
2664 	}
2665 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_BIGALLOC) &&
2666 	    !EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
2667 		ext4_msg(sb, KERN_ERR,
2668 			 "Can't support bigalloc feature without "
2669 			 "extents feature\n");
2670 		return 0;
2671 	}
2672 
2673 #ifndef CONFIG_QUOTA
2674 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA) &&
2675 	    !readonly) {
2676 		ext4_msg(sb, KERN_ERR,
2677 			 "Filesystem with quota feature cannot be mounted RDWR "
2678 			 "without CONFIG_QUOTA");
2679 		return 0;
2680 	}
2681 #endif  /* CONFIG_QUOTA */
2682 	return 1;
2683 }
2684 
2685 /*
2686  * This function is called once a day if we have errors logged
2687  * on the file system
2688  */
2689 static void print_daily_error_info(unsigned long arg)
2690 {
2691 	struct super_block *sb = (struct super_block *) arg;
2692 	struct ext4_sb_info *sbi;
2693 	struct ext4_super_block *es;
2694 
2695 	sbi = EXT4_SB(sb);
2696 	es = sbi->s_es;
2697 
2698 	if (es->s_error_count)
2699 		ext4_msg(sb, KERN_NOTICE, "error count: %u",
2700 			 le32_to_cpu(es->s_error_count));
2701 	if (es->s_first_error_time) {
2702 		printk(KERN_NOTICE "EXT4-fs (%s): initial error at %u: %.*s:%d",
2703 		       sb->s_id, le32_to_cpu(es->s_first_error_time),
2704 		       (int) sizeof(es->s_first_error_func),
2705 		       es->s_first_error_func,
2706 		       le32_to_cpu(es->s_first_error_line));
2707 		if (es->s_first_error_ino)
2708 			printk(": inode %u",
2709 			       le32_to_cpu(es->s_first_error_ino));
2710 		if (es->s_first_error_block)
2711 			printk(": block %llu", (unsigned long long)
2712 			       le64_to_cpu(es->s_first_error_block));
2713 		printk("\n");
2714 	}
2715 	if (es->s_last_error_time) {
2716 		printk(KERN_NOTICE "EXT4-fs (%s): last error at %u: %.*s:%d",
2717 		       sb->s_id, le32_to_cpu(es->s_last_error_time),
2718 		       (int) sizeof(es->s_last_error_func),
2719 		       es->s_last_error_func,
2720 		       le32_to_cpu(es->s_last_error_line));
2721 		if (es->s_last_error_ino)
2722 			printk(": inode %u",
2723 			       le32_to_cpu(es->s_last_error_ino));
2724 		if (es->s_last_error_block)
2725 			printk(": block %llu", (unsigned long long)
2726 			       le64_to_cpu(es->s_last_error_block));
2727 		printk("\n");
2728 	}
2729 	mod_timer(&sbi->s_err_report, jiffies + 24*60*60*HZ);  /* Once a day */
2730 }
2731 
2732 /* Find next suitable group and run ext4_init_inode_table */
2733 static int ext4_run_li_request(struct ext4_li_request *elr)
2734 {
2735 	struct ext4_group_desc *gdp = NULL;
2736 	ext4_group_t group, ngroups;
2737 	struct super_block *sb;
2738 	unsigned long timeout = 0;
2739 	int ret = 0;
2740 
2741 	sb = elr->lr_super;
2742 	ngroups = EXT4_SB(sb)->s_groups_count;
2743 
2744 	sb_start_write(sb);
2745 	for (group = elr->lr_next_group; group < ngroups; group++) {
2746 		gdp = ext4_get_group_desc(sb, group, NULL);
2747 		if (!gdp) {
2748 			ret = 1;
2749 			break;
2750 		}
2751 
2752 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2753 			break;
2754 	}
2755 
2756 	if (group >= ngroups)
2757 		ret = 1;
2758 
2759 	if (!ret) {
2760 		timeout = jiffies;
2761 		ret = ext4_init_inode_table(sb, group,
2762 					    elr->lr_timeout ? 0 : 1);
2763 		if (elr->lr_timeout == 0) {
2764 			timeout = (jiffies - timeout) *
2765 				  elr->lr_sbi->s_li_wait_mult;
2766 			elr->lr_timeout = timeout;
2767 		}
2768 		elr->lr_next_sched = jiffies + elr->lr_timeout;
2769 		elr->lr_next_group = group + 1;
2770 	}
2771 	sb_end_write(sb);
2772 
2773 	return ret;
2774 }
2775 
2776 /*
2777  * Remove lr_request from the list_request and free the
2778  * request structure. Should be called with li_list_mtx held
2779  */
2780 static void ext4_remove_li_request(struct ext4_li_request *elr)
2781 {
2782 	struct ext4_sb_info *sbi;
2783 
2784 	if (!elr)
2785 		return;
2786 
2787 	sbi = elr->lr_sbi;
2788 
2789 	list_del(&elr->lr_request);
2790 	sbi->s_li_request = NULL;
2791 	kfree(elr);
2792 }
2793 
2794 static void ext4_unregister_li_request(struct super_block *sb)
2795 {
2796 	mutex_lock(&ext4_li_mtx);
2797 	if (!ext4_li_info) {
2798 		mutex_unlock(&ext4_li_mtx);
2799 		return;
2800 	}
2801 
2802 	mutex_lock(&ext4_li_info->li_list_mtx);
2803 	ext4_remove_li_request(EXT4_SB(sb)->s_li_request);
2804 	mutex_unlock(&ext4_li_info->li_list_mtx);
2805 	mutex_unlock(&ext4_li_mtx);
2806 }
2807 
2808 static struct task_struct *ext4_lazyinit_task;
2809 
2810 /*
2811  * This is the function where ext4lazyinit thread lives. It walks
2812  * through the request list searching for next scheduled filesystem.
2813  * When such a fs is found, run the lazy initialization request
2814  * (ext4_rn_li_request) and keep track of the time spend in this
2815  * function. Based on that time we compute next schedule time of
2816  * the request. When walking through the list is complete, compute
2817  * next waking time and put itself into sleep.
2818  */
2819 static int ext4_lazyinit_thread(void *arg)
2820 {
2821 	struct ext4_lazy_init *eli = (struct ext4_lazy_init *)arg;
2822 	struct list_head *pos, *n;
2823 	struct ext4_li_request *elr;
2824 	unsigned long next_wakeup, cur;
2825 
2826 	BUG_ON(NULL == eli);
2827 
2828 cont_thread:
2829 	while (true) {
2830 		next_wakeup = MAX_JIFFY_OFFSET;
2831 
2832 		mutex_lock(&eli->li_list_mtx);
2833 		if (list_empty(&eli->li_request_list)) {
2834 			mutex_unlock(&eli->li_list_mtx);
2835 			goto exit_thread;
2836 		}
2837 
2838 		list_for_each_safe(pos, n, &eli->li_request_list) {
2839 			elr = list_entry(pos, struct ext4_li_request,
2840 					 lr_request);
2841 
2842 			if (time_after_eq(jiffies, elr->lr_next_sched)) {
2843 				if (ext4_run_li_request(elr) != 0) {
2844 					/* error, remove the lazy_init job */
2845 					ext4_remove_li_request(elr);
2846 					continue;
2847 				}
2848 			}
2849 
2850 			if (time_before(elr->lr_next_sched, next_wakeup))
2851 				next_wakeup = elr->lr_next_sched;
2852 		}
2853 		mutex_unlock(&eli->li_list_mtx);
2854 
2855 		try_to_freeze();
2856 
2857 		cur = jiffies;
2858 		if ((time_after_eq(cur, next_wakeup)) ||
2859 		    (MAX_JIFFY_OFFSET == next_wakeup)) {
2860 			cond_resched();
2861 			continue;
2862 		}
2863 
2864 		schedule_timeout_interruptible(next_wakeup - cur);
2865 
2866 		if (kthread_should_stop()) {
2867 			ext4_clear_request_list();
2868 			goto exit_thread;
2869 		}
2870 	}
2871 
2872 exit_thread:
2873 	/*
2874 	 * It looks like the request list is empty, but we need
2875 	 * to check it under the li_list_mtx lock, to prevent any
2876 	 * additions into it, and of course we should lock ext4_li_mtx
2877 	 * to atomically free the list and ext4_li_info, because at
2878 	 * this point another ext4 filesystem could be registering
2879 	 * new one.
2880 	 */
2881 	mutex_lock(&ext4_li_mtx);
2882 	mutex_lock(&eli->li_list_mtx);
2883 	if (!list_empty(&eli->li_request_list)) {
2884 		mutex_unlock(&eli->li_list_mtx);
2885 		mutex_unlock(&ext4_li_mtx);
2886 		goto cont_thread;
2887 	}
2888 	mutex_unlock(&eli->li_list_mtx);
2889 	kfree(ext4_li_info);
2890 	ext4_li_info = NULL;
2891 	mutex_unlock(&ext4_li_mtx);
2892 
2893 	return 0;
2894 }
2895 
2896 static void ext4_clear_request_list(void)
2897 {
2898 	struct list_head *pos, *n;
2899 	struct ext4_li_request *elr;
2900 
2901 	mutex_lock(&ext4_li_info->li_list_mtx);
2902 	list_for_each_safe(pos, n, &ext4_li_info->li_request_list) {
2903 		elr = list_entry(pos, struct ext4_li_request,
2904 				 lr_request);
2905 		ext4_remove_li_request(elr);
2906 	}
2907 	mutex_unlock(&ext4_li_info->li_list_mtx);
2908 }
2909 
2910 static int ext4_run_lazyinit_thread(void)
2911 {
2912 	ext4_lazyinit_task = kthread_run(ext4_lazyinit_thread,
2913 					 ext4_li_info, "ext4lazyinit");
2914 	if (IS_ERR(ext4_lazyinit_task)) {
2915 		int err = PTR_ERR(ext4_lazyinit_task);
2916 		ext4_clear_request_list();
2917 		kfree(ext4_li_info);
2918 		ext4_li_info = NULL;
2919 		printk(KERN_CRIT "EXT4-fs: error %d creating inode table "
2920 				 "initialization thread\n",
2921 				 err);
2922 		return err;
2923 	}
2924 	ext4_li_info->li_state |= EXT4_LAZYINIT_RUNNING;
2925 	return 0;
2926 }
2927 
2928 /*
2929  * Check whether it make sense to run itable init. thread or not.
2930  * If there is at least one uninitialized inode table, return
2931  * corresponding group number, else the loop goes through all
2932  * groups and return total number of groups.
2933  */
2934 static ext4_group_t ext4_has_uninit_itable(struct super_block *sb)
2935 {
2936 	ext4_group_t group, ngroups = EXT4_SB(sb)->s_groups_count;
2937 	struct ext4_group_desc *gdp = NULL;
2938 
2939 	for (group = 0; group < ngroups; group++) {
2940 		gdp = ext4_get_group_desc(sb, group, NULL);
2941 		if (!gdp)
2942 			continue;
2943 
2944 		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
2945 			break;
2946 	}
2947 
2948 	return group;
2949 }
2950 
2951 static int ext4_li_info_new(void)
2952 {
2953 	struct ext4_lazy_init *eli = NULL;
2954 
2955 	eli = kzalloc(sizeof(*eli), GFP_KERNEL);
2956 	if (!eli)
2957 		return -ENOMEM;
2958 
2959 	INIT_LIST_HEAD(&eli->li_request_list);
2960 	mutex_init(&eli->li_list_mtx);
2961 
2962 	eli->li_state |= EXT4_LAZYINIT_QUIT;
2963 
2964 	ext4_li_info = eli;
2965 
2966 	return 0;
2967 }
2968 
2969 static struct ext4_li_request *ext4_li_request_new(struct super_block *sb,
2970 					    ext4_group_t start)
2971 {
2972 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2973 	struct ext4_li_request *elr;
2974 	unsigned long rnd;
2975 
2976 	elr = kzalloc(sizeof(*elr), GFP_KERNEL);
2977 	if (!elr)
2978 		return NULL;
2979 
2980 	elr->lr_super = sb;
2981 	elr->lr_sbi = sbi;
2982 	elr->lr_next_group = start;
2983 
2984 	/*
2985 	 * Randomize first schedule time of the request to
2986 	 * spread the inode table initialization requests
2987 	 * better.
2988 	 */
2989 	get_random_bytes(&rnd, sizeof(rnd));
2990 	elr->lr_next_sched = jiffies + (unsigned long)rnd %
2991 			     (EXT4_DEF_LI_MAX_START_DELAY * HZ);
2992 
2993 	return elr;
2994 }
2995 
2996 int ext4_register_li_request(struct super_block *sb,
2997 			     ext4_group_t first_not_zeroed)
2998 {
2999 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3000 	struct ext4_li_request *elr = NULL;
3001 	ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
3002 	int ret = 0;
3003 
3004 	mutex_lock(&ext4_li_mtx);
3005 	if (sbi->s_li_request != NULL) {
3006 		/*
3007 		 * Reset timeout so it can be computed again, because
3008 		 * s_li_wait_mult might have changed.
3009 		 */
3010 		sbi->s_li_request->lr_timeout = 0;
3011 		goto out;
3012 	}
3013 
3014 	if (first_not_zeroed == ngroups ||
3015 	    (sb->s_flags & MS_RDONLY) ||
3016 	    !test_opt(sb, INIT_INODE_TABLE))
3017 		goto out;
3018 
3019 	elr = ext4_li_request_new(sb, first_not_zeroed);
3020 	if (!elr) {
3021 		ret = -ENOMEM;
3022 		goto out;
3023 	}
3024 
3025 	if (NULL == ext4_li_info) {
3026 		ret = ext4_li_info_new();
3027 		if (ret)
3028 			goto out;
3029 	}
3030 
3031 	mutex_lock(&ext4_li_info->li_list_mtx);
3032 	list_add(&elr->lr_request, &ext4_li_info->li_request_list);
3033 	mutex_unlock(&ext4_li_info->li_list_mtx);
3034 
3035 	sbi->s_li_request = elr;
3036 	/*
3037 	 * set elr to NULL here since it has been inserted to
3038 	 * the request_list and the removal and free of it is
3039 	 * handled by ext4_clear_request_list from now on.
3040 	 */
3041 	elr = NULL;
3042 
3043 	if (!(ext4_li_info->li_state & EXT4_LAZYINIT_RUNNING)) {
3044 		ret = ext4_run_lazyinit_thread();
3045 		if (ret)
3046 			goto out;
3047 	}
3048 out:
3049 	mutex_unlock(&ext4_li_mtx);
3050 	if (ret)
3051 		kfree(elr);
3052 	return ret;
3053 }
3054 
3055 /*
3056  * We do not need to lock anything since this is called on
3057  * module unload.
3058  */
3059 static void ext4_destroy_lazyinit_thread(void)
3060 {
3061 	/*
3062 	 * If thread exited earlier
3063 	 * there's nothing to be done.
3064 	 */
3065 	if (!ext4_li_info || !ext4_lazyinit_task)
3066 		return;
3067 
3068 	kthread_stop(ext4_lazyinit_task);
3069 }
3070 
3071 static int set_journal_csum_feature_set(struct super_block *sb)
3072 {
3073 	int ret = 1;
3074 	int compat, incompat;
3075 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3076 
3077 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3078 				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
3079 		/* journal checksum v2 */
3080 		compat = 0;
3081 		incompat = JBD2_FEATURE_INCOMPAT_CSUM_V2;
3082 	} else {
3083 		/* journal checksum v1 */
3084 		compat = JBD2_FEATURE_COMPAT_CHECKSUM;
3085 		incompat = 0;
3086 	}
3087 
3088 	if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
3089 		ret = jbd2_journal_set_features(sbi->s_journal,
3090 				compat, 0,
3091 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT |
3092 				incompat);
3093 	} else if (test_opt(sb, JOURNAL_CHECKSUM)) {
3094 		ret = jbd2_journal_set_features(sbi->s_journal,
3095 				compat, 0,
3096 				incompat);
3097 		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
3098 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
3099 	} else {
3100 		jbd2_journal_clear_features(sbi->s_journal,
3101 				JBD2_FEATURE_COMPAT_CHECKSUM, 0,
3102 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT |
3103 				JBD2_FEATURE_INCOMPAT_CSUM_V2);
3104 	}
3105 
3106 	return ret;
3107 }
3108 
3109 /*
3110  * Note: calculating the overhead so we can be compatible with
3111  * historical BSD practice is quite difficult in the face of
3112  * clusters/bigalloc.  This is because multiple metadata blocks from
3113  * different block group can end up in the same allocation cluster.
3114  * Calculating the exact overhead in the face of clustered allocation
3115  * requires either O(all block bitmaps) in memory or O(number of block
3116  * groups**2) in time.  We will still calculate the superblock for
3117  * older file systems --- and if we come across with a bigalloc file
3118  * system with zero in s_overhead_clusters the estimate will be close to
3119  * correct especially for very large cluster sizes --- but for newer
3120  * file systems, it's better to calculate this figure once at mkfs
3121  * time, and store it in the superblock.  If the superblock value is
3122  * present (even for non-bigalloc file systems), we will use it.
3123  */
3124 static int count_overhead(struct super_block *sb, ext4_group_t grp,
3125 			  char *buf)
3126 {
3127 	struct ext4_sb_info	*sbi = EXT4_SB(sb);
3128 	struct ext4_group_desc	*gdp;
3129 	ext4_fsblk_t		first_block, last_block, b;
3130 	ext4_group_t		i, ngroups = ext4_get_groups_count(sb);
3131 	int			s, j, count = 0;
3132 
3133 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_BIGALLOC))
3134 		return (ext4_bg_has_super(sb, grp) + ext4_bg_num_gdb(sb, grp) +
3135 			sbi->s_itb_per_group + 2);
3136 
3137 	first_block = le32_to_cpu(sbi->s_es->s_first_data_block) +
3138 		(grp * EXT4_BLOCKS_PER_GROUP(sb));
3139 	last_block = first_block + EXT4_BLOCKS_PER_GROUP(sb) - 1;
3140 	for (i = 0; i < ngroups; i++) {
3141 		gdp = ext4_get_group_desc(sb, i, NULL);
3142 		b = ext4_block_bitmap(sb, gdp);
3143 		if (b >= first_block && b <= last_block) {
3144 			ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf);
3145 			count++;
3146 		}
3147 		b = ext4_inode_bitmap(sb, gdp);
3148 		if (b >= first_block && b <= last_block) {
3149 			ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf);
3150 			count++;
3151 		}
3152 		b = ext4_inode_table(sb, gdp);
3153 		if (b >= first_block && b + sbi->s_itb_per_group <= last_block)
3154 			for (j = 0; j < sbi->s_itb_per_group; j++, b++) {
3155 				int c = EXT4_B2C(sbi, b - first_block);
3156 				ext4_set_bit(c, buf);
3157 				count++;
3158 			}
3159 		if (i != grp)
3160 			continue;
3161 		s = 0;
3162 		if (ext4_bg_has_super(sb, grp)) {
3163 			ext4_set_bit(s++, buf);
3164 			count++;
3165 		}
3166 		for (j = ext4_bg_num_gdb(sb, grp); j > 0; j--) {
3167 			ext4_set_bit(EXT4_B2C(sbi, s++), buf);
3168 			count++;
3169 		}
3170 	}
3171 	if (!count)
3172 		return 0;
3173 	return EXT4_CLUSTERS_PER_GROUP(sb) -
3174 		ext4_count_free(buf, EXT4_CLUSTERS_PER_GROUP(sb) / 8);
3175 }
3176 
3177 /*
3178  * Compute the overhead and stash it in sbi->s_overhead
3179  */
3180 int ext4_calculate_overhead(struct super_block *sb)
3181 {
3182 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3183 	struct ext4_super_block *es = sbi->s_es;
3184 	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
3185 	ext4_fsblk_t overhead = 0;
3186 	char *buf = (char *) get_zeroed_page(GFP_KERNEL);
3187 
3188 	if (!buf)
3189 		return -ENOMEM;
3190 
3191 	/*
3192 	 * Compute the overhead (FS structures).  This is constant
3193 	 * for a given filesystem unless the number of block groups
3194 	 * changes so we cache the previous value until it does.
3195 	 */
3196 
3197 	/*
3198 	 * All of the blocks before first_data_block are overhead
3199 	 */
3200 	overhead = EXT4_B2C(sbi, le32_to_cpu(es->s_first_data_block));
3201 
3202 	/*
3203 	 * Add the overhead found in each block group
3204 	 */
3205 	for (i = 0; i < ngroups; i++) {
3206 		int blks;
3207 
3208 		blks = count_overhead(sb, i, buf);
3209 		overhead += blks;
3210 		if (blks)
3211 			memset(buf, 0, PAGE_SIZE);
3212 		cond_resched();
3213 	}
3214 	/* Add the journal blocks as well */
3215 	if (sbi->s_journal)
3216 		overhead += EXT4_NUM_B2C(sbi, sbi->s_journal->j_maxlen);
3217 
3218 	sbi->s_overhead = overhead;
3219 	smp_wmb();
3220 	free_page((unsigned long) buf);
3221 	return 0;
3222 }
3223 
3224 
3225 static ext4_fsblk_t ext4_calculate_resv_clusters(struct ext4_sb_info *sbi)
3226 {
3227 	ext4_fsblk_t resv_clusters;
3228 
3229 	/*
3230 	 * By default we reserve 2% or 4096 clusters, whichever is smaller.
3231 	 * This should cover the situations where we can not afford to run
3232 	 * out of space like for example punch hole, or converting
3233 	 * uninitialized extents in delalloc path. In most cases such
3234 	 * allocation would require 1, or 2 blocks, higher numbers are
3235 	 * very rare.
3236 	 */
3237 	resv_clusters = ext4_blocks_count(sbi->s_es) >> sbi->s_cluster_bits;
3238 
3239 	do_div(resv_clusters, 50);
3240 	resv_clusters = min_t(ext4_fsblk_t, resv_clusters, 4096);
3241 
3242 	return resv_clusters;
3243 }
3244 
3245 
3246 static int ext4_reserve_clusters(struct ext4_sb_info *sbi, ext4_fsblk_t count)
3247 {
3248 	ext4_fsblk_t clusters = ext4_blocks_count(sbi->s_es) >>
3249 				sbi->s_cluster_bits;
3250 
3251 	if (count >= clusters)
3252 		return -EINVAL;
3253 
3254 	atomic64_set(&sbi->s_resv_clusters, count);
3255 	return 0;
3256 }
3257 
3258 static int ext4_fill_super(struct super_block *sb, void *data, int silent)
3259 {
3260 	char *orig_data = kstrdup(data, GFP_KERNEL);
3261 	struct buffer_head *bh;
3262 	struct ext4_super_block *es = NULL;
3263 	struct ext4_sb_info *sbi;
3264 	ext4_fsblk_t block;
3265 	ext4_fsblk_t sb_block = get_sb_block(&data);
3266 	ext4_fsblk_t logical_sb_block;
3267 	unsigned long offset = 0;
3268 	unsigned long journal_devnum = 0;
3269 	unsigned long def_mount_opts;
3270 	struct inode *root;
3271 	char *cp;
3272 	const char *descr;
3273 	int ret = -ENOMEM;
3274 	int blocksize, clustersize;
3275 	unsigned int db_count;
3276 	unsigned int i;
3277 	int needs_recovery, has_huge_files, has_bigalloc;
3278 	__u64 blocks_count;
3279 	int err = 0;
3280 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
3281 	ext4_group_t first_not_zeroed;
3282 
3283 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
3284 	if (!sbi)
3285 		goto out_free_orig;
3286 
3287 	sbi->s_blockgroup_lock =
3288 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
3289 	if (!sbi->s_blockgroup_lock) {
3290 		kfree(sbi);
3291 		goto out_free_orig;
3292 	}
3293 	sb->s_fs_info = sbi;
3294 	sbi->s_sb = sb;
3295 	sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
3296 	sbi->s_sb_block = sb_block;
3297 	if (sb->s_bdev->bd_part)
3298 		sbi->s_sectors_written_start =
3299 			part_stat_read(sb->s_bdev->bd_part, sectors[1]);
3300 
3301 	/* Cleanup superblock name */
3302 	for (cp = sb->s_id; (cp = strchr(cp, '/'));)
3303 		*cp = '!';
3304 
3305 	/* -EINVAL is default */
3306 	ret = -EINVAL;
3307 	blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
3308 	if (!blocksize) {
3309 		ext4_msg(sb, KERN_ERR, "unable to set blocksize");
3310 		goto out_fail;
3311 	}
3312 
3313 	/*
3314 	 * The ext4 superblock will not be buffer aligned for other than 1kB
3315 	 * block sizes.  We need to calculate the offset from buffer start.
3316 	 */
3317 	if (blocksize != EXT4_MIN_BLOCK_SIZE) {
3318 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3319 		offset = do_div(logical_sb_block, blocksize);
3320 	} else {
3321 		logical_sb_block = sb_block;
3322 	}
3323 
3324 	if (!(bh = sb_bread(sb, logical_sb_block))) {
3325 		ext4_msg(sb, KERN_ERR, "unable to read superblock");
3326 		goto out_fail;
3327 	}
3328 	/*
3329 	 * Note: s_es must be initialized as soon as possible because
3330 	 *       some ext4 macro-instructions depend on its value
3331 	 */
3332 	es = (struct ext4_super_block *) (bh->b_data + offset);
3333 	sbi->s_es = es;
3334 	sb->s_magic = le16_to_cpu(es->s_magic);
3335 	if (sb->s_magic != EXT4_SUPER_MAGIC)
3336 		goto cantfind_ext4;
3337 	sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
3338 
3339 	/* Warn if metadata_csum and gdt_csum are both set. */
3340 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3341 				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
3342 	    EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
3343 		ext4_warning(sb, KERN_INFO "metadata_csum and uninit_bg are "
3344 			     "redundant flags; please run fsck.");
3345 
3346 	/* Check for a known checksum algorithm */
3347 	if (!ext4_verify_csum_type(sb, es)) {
3348 		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
3349 			 "unknown checksum algorithm.");
3350 		silent = 1;
3351 		goto cantfind_ext4;
3352 	}
3353 
3354 	/* Load the checksum driver */
3355 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3356 				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
3357 		sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
3358 		if (IS_ERR(sbi->s_chksum_driver)) {
3359 			ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
3360 			ret = PTR_ERR(sbi->s_chksum_driver);
3361 			sbi->s_chksum_driver = NULL;
3362 			goto failed_mount;
3363 		}
3364 	}
3365 
3366 	/* Check superblock checksum */
3367 	if (!ext4_superblock_csum_verify(sb, es)) {
3368 		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
3369 			 "invalid superblock checksum.  Run e2fsck?");
3370 		silent = 1;
3371 		goto cantfind_ext4;
3372 	}
3373 
3374 	/* Precompute checksum seed for all metadata */
3375 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3376 			EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
3377 		sbi->s_csum_seed = ext4_chksum(sbi, ~0, es->s_uuid,
3378 					       sizeof(es->s_uuid));
3379 
3380 	/* Set defaults before we parse the mount options */
3381 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
3382 	set_opt(sb, INIT_INODE_TABLE);
3383 	if (def_mount_opts & EXT4_DEFM_DEBUG)
3384 		set_opt(sb, DEBUG);
3385 	if (def_mount_opts & EXT4_DEFM_BSDGROUPS)
3386 		set_opt(sb, GRPID);
3387 	if (def_mount_opts & EXT4_DEFM_UID16)
3388 		set_opt(sb, NO_UID32);
3389 	/* xattr user namespace & acls are now defaulted on */
3390 	set_opt(sb, XATTR_USER);
3391 #ifdef CONFIG_EXT4_FS_POSIX_ACL
3392 	set_opt(sb, POSIX_ACL);
3393 #endif
3394 	if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA)
3395 		set_opt(sb, JOURNAL_DATA);
3396 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_ORDERED)
3397 		set_opt(sb, ORDERED_DATA);
3398 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_WBACK)
3399 		set_opt(sb, WRITEBACK_DATA);
3400 
3401 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_PANIC)
3402 		set_opt(sb, ERRORS_PANIC);
3403 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_CONTINUE)
3404 		set_opt(sb, ERRORS_CONT);
3405 	else
3406 		set_opt(sb, ERRORS_RO);
3407 	if (def_mount_opts & EXT4_DEFM_BLOCK_VALIDITY)
3408 		set_opt(sb, BLOCK_VALIDITY);
3409 	if (def_mount_opts & EXT4_DEFM_DISCARD)
3410 		set_opt(sb, DISCARD);
3411 
3412 	sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
3413 	sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
3414 	sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ;
3415 	sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;
3416 	sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;
3417 
3418 	if ((def_mount_opts & EXT4_DEFM_NOBARRIER) == 0)
3419 		set_opt(sb, BARRIER);
3420 
3421 	/*
3422 	 * enable delayed allocation by default
3423 	 * Use -o nodelalloc to turn it off
3424 	 */
3425 	if (!IS_EXT3_SB(sb) && !IS_EXT2_SB(sb) &&
3426 	    ((def_mount_opts & EXT4_DEFM_NODELALLOC) == 0))
3427 		set_opt(sb, DELALLOC);
3428 
3429 	/*
3430 	 * set default s_li_wait_mult for lazyinit, for the case there is
3431 	 * no mount option specified.
3432 	 */
3433 	sbi->s_li_wait_mult = EXT4_DEF_LI_WAIT_MULT;
3434 
3435 	if (!parse_options((char *) sbi->s_es->s_mount_opts, sb,
3436 			   &journal_devnum, &journal_ioprio, 0)) {
3437 		ext4_msg(sb, KERN_WARNING,
3438 			 "failed to parse options in superblock: %s",
3439 			 sbi->s_es->s_mount_opts);
3440 	}
3441 	sbi->s_def_mount_opt = sbi->s_mount_opt;
3442 	if (!parse_options((char *) data, sb, &journal_devnum,
3443 			   &journal_ioprio, 0))
3444 		goto failed_mount;
3445 
3446 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
3447 		printk_once(KERN_WARNING "EXT4-fs: Warning: mounting "
3448 			    "with data=journal disables delayed "
3449 			    "allocation and O_DIRECT support!\n");
3450 		if (test_opt2(sb, EXPLICIT_DELALLOC)) {
3451 			ext4_msg(sb, KERN_ERR, "can't mount with "
3452 				 "both data=journal and delalloc");
3453 			goto failed_mount;
3454 		}
3455 		if (test_opt(sb, DIOREAD_NOLOCK)) {
3456 			ext4_msg(sb, KERN_ERR, "can't mount with "
3457 				 "both data=journal and delalloc");
3458 			goto failed_mount;
3459 		}
3460 		if (test_opt(sb, DELALLOC))
3461 			clear_opt(sb, DELALLOC);
3462 	}
3463 
3464 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
3465 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
3466 
3467 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
3468 	    (EXT4_HAS_COMPAT_FEATURE(sb, ~0U) ||
3469 	     EXT4_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
3470 	     EXT4_HAS_INCOMPAT_FEATURE(sb, ~0U)))
3471 		ext4_msg(sb, KERN_WARNING,
3472 		       "feature flags set on rev 0 fs, "
3473 		       "running e2fsck is recommended");
3474 
3475 	if (IS_EXT2_SB(sb)) {
3476 		if (ext2_feature_set_ok(sb))
3477 			ext4_msg(sb, KERN_INFO, "mounting ext2 file system "
3478 				 "using the ext4 subsystem");
3479 		else {
3480 			ext4_msg(sb, KERN_ERR, "couldn't mount as ext2 due "
3481 				 "to feature incompatibilities");
3482 			goto failed_mount;
3483 		}
3484 	}
3485 
3486 	if (IS_EXT3_SB(sb)) {
3487 		if (ext3_feature_set_ok(sb))
3488 			ext4_msg(sb, KERN_INFO, "mounting ext3 file system "
3489 				 "using the ext4 subsystem");
3490 		else {
3491 			ext4_msg(sb, KERN_ERR, "couldn't mount as ext3 due "
3492 				 "to feature incompatibilities");
3493 			goto failed_mount;
3494 		}
3495 	}
3496 
3497 	/*
3498 	 * Check feature flags regardless of the revision level, since we
3499 	 * previously didn't change the revision level when setting the flags,
3500 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
3501 	 */
3502 	if (!ext4_feature_set_ok(sb, (sb->s_flags & MS_RDONLY)))
3503 		goto failed_mount;
3504 
3505 	blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
3506 	if (blocksize < EXT4_MIN_BLOCK_SIZE ||
3507 	    blocksize > EXT4_MAX_BLOCK_SIZE) {
3508 		ext4_msg(sb, KERN_ERR,
3509 		       "Unsupported filesystem blocksize %d", blocksize);
3510 		goto failed_mount;
3511 	}
3512 
3513 	if (sb->s_blocksize != blocksize) {
3514 		/* Validate the filesystem blocksize */
3515 		if (!sb_set_blocksize(sb, blocksize)) {
3516 			ext4_msg(sb, KERN_ERR, "bad block size %d",
3517 					blocksize);
3518 			goto failed_mount;
3519 		}
3520 
3521 		brelse(bh);
3522 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
3523 		offset = do_div(logical_sb_block, blocksize);
3524 		bh = sb_bread(sb, logical_sb_block);
3525 		if (!bh) {
3526 			ext4_msg(sb, KERN_ERR,
3527 			       "Can't read superblock on 2nd try");
3528 			goto failed_mount;
3529 		}
3530 		es = (struct ext4_super_block *)(bh->b_data + offset);
3531 		sbi->s_es = es;
3532 		if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
3533 			ext4_msg(sb, KERN_ERR,
3534 			       "Magic mismatch, very weird!");
3535 			goto failed_mount;
3536 		}
3537 	}
3538 
3539 	has_huge_files = EXT4_HAS_RO_COMPAT_FEATURE(sb,
3540 				EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
3541 	sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits,
3542 						      has_huge_files);
3543 	sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits, has_huge_files);
3544 
3545 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) {
3546 		sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE;
3547 		sbi->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
3548 	} else {
3549 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
3550 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
3551 		if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
3552 		    (!is_power_of_2(sbi->s_inode_size)) ||
3553 		    (sbi->s_inode_size > blocksize)) {
3554 			ext4_msg(sb, KERN_ERR,
3555 			       "unsupported inode size: %d",
3556 			       sbi->s_inode_size);
3557 			goto failed_mount;
3558 		}
3559 		if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE)
3560 			sb->s_time_gran = 1 << (EXT4_EPOCH_BITS - 2);
3561 	}
3562 
3563 	sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
3564 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT)) {
3565 		if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT ||
3566 		    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
3567 		    !is_power_of_2(sbi->s_desc_size)) {
3568 			ext4_msg(sb, KERN_ERR,
3569 			       "unsupported descriptor size %lu",
3570 			       sbi->s_desc_size);
3571 			goto failed_mount;
3572 		}
3573 	} else
3574 		sbi->s_desc_size = EXT4_MIN_DESC_SIZE;
3575 
3576 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
3577 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
3578 	if (EXT4_INODE_SIZE(sb) == 0 || EXT4_INODES_PER_GROUP(sb) == 0)
3579 		goto cantfind_ext4;
3580 
3581 	sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
3582 	if (sbi->s_inodes_per_block == 0)
3583 		goto cantfind_ext4;
3584 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
3585 					sbi->s_inodes_per_block;
3586 	sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
3587 	sbi->s_sbh = bh;
3588 	sbi->s_mount_state = le16_to_cpu(es->s_state);
3589 	sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
3590 	sbi->s_desc_per_block_bits = ilog2(EXT4_DESC_PER_BLOCK(sb));
3591 
3592 	/* Do we have standard group size of blocksize * 8 blocks ? */
3593 	if (sbi->s_blocks_per_group == blocksize << 3)
3594 		set_opt2(sb, STD_GROUP_SIZE);
3595 
3596 	for (i = 0; i < 4; i++)
3597 		sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
3598 	sbi->s_def_hash_version = es->s_def_hash_version;
3599 	i = le32_to_cpu(es->s_flags);
3600 	if (i & EXT2_FLAGS_UNSIGNED_HASH)
3601 		sbi->s_hash_unsigned = 3;
3602 	else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) {
3603 #ifdef __CHAR_UNSIGNED__
3604 		es->s_flags |= cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH);
3605 		sbi->s_hash_unsigned = 3;
3606 #else
3607 		es->s_flags |= cpu_to_le32(EXT2_FLAGS_SIGNED_HASH);
3608 #endif
3609 	}
3610 
3611 	/* Handle clustersize */
3612 	clustersize = BLOCK_SIZE << le32_to_cpu(es->s_log_cluster_size);
3613 	has_bigalloc = EXT4_HAS_RO_COMPAT_FEATURE(sb,
3614 				EXT4_FEATURE_RO_COMPAT_BIGALLOC);
3615 	if (has_bigalloc) {
3616 		if (clustersize < blocksize) {
3617 			ext4_msg(sb, KERN_ERR,
3618 				 "cluster size (%d) smaller than "
3619 				 "block size (%d)", clustersize, blocksize);
3620 			goto failed_mount;
3621 		}
3622 		sbi->s_cluster_bits = le32_to_cpu(es->s_log_cluster_size) -
3623 			le32_to_cpu(es->s_log_block_size);
3624 		sbi->s_clusters_per_group =
3625 			le32_to_cpu(es->s_clusters_per_group);
3626 		if (sbi->s_clusters_per_group > blocksize * 8) {
3627 			ext4_msg(sb, KERN_ERR,
3628 				 "#clusters per group too big: %lu",
3629 				 sbi->s_clusters_per_group);
3630 			goto failed_mount;
3631 		}
3632 		if (sbi->s_blocks_per_group !=
3633 		    (sbi->s_clusters_per_group * (clustersize / blocksize))) {
3634 			ext4_msg(sb, KERN_ERR, "blocks per group (%lu) and "
3635 				 "clusters per group (%lu) inconsistent",
3636 				 sbi->s_blocks_per_group,
3637 				 sbi->s_clusters_per_group);
3638 			goto failed_mount;
3639 		}
3640 	} else {
3641 		if (clustersize != blocksize) {
3642 			ext4_warning(sb, "fragment/cluster size (%d) != "
3643 				     "block size (%d)", clustersize,
3644 				     blocksize);
3645 			clustersize = blocksize;
3646 		}
3647 		if (sbi->s_blocks_per_group > blocksize * 8) {
3648 			ext4_msg(sb, KERN_ERR,
3649 				 "#blocks per group too big: %lu",
3650 				 sbi->s_blocks_per_group);
3651 			goto failed_mount;
3652 		}
3653 		sbi->s_clusters_per_group = sbi->s_blocks_per_group;
3654 		sbi->s_cluster_bits = 0;
3655 	}
3656 	sbi->s_cluster_ratio = clustersize / blocksize;
3657 
3658 	if (sbi->s_inodes_per_group > blocksize * 8) {
3659 		ext4_msg(sb, KERN_ERR,
3660 		       "#inodes per group too big: %lu",
3661 		       sbi->s_inodes_per_group);
3662 		goto failed_mount;
3663 	}
3664 
3665 	/*
3666 	 * Test whether we have more sectors than will fit in sector_t,
3667 	 * and whether the max offset is addressable by the page cache.
3668 	 */
3669 	err = generic_check_addressable(sb->s_blocksize_bits,
3670 					ext4_blocks_count(es));
3671 	if (err) {
3672 		ext4_msg(sb, KERN_ERR, "filesystem"
3673 			 " too large to mount safely on this system");
3674 		if (sizeof(sector_t) < 8)
3675 			ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled");
3676 		goto failed_mount;
3677 	}
3678 
3679 	if (EXT4_BLOCKS_PER_GROUP(sb) == 0)
3680 		goto cantfind_ext4;
3681 
3682 	/* check blocks count against device size */
3683 	blocks_count = sb->s_bdev->bd_inode->i_size >> sb->s_blocksize_bits;
3684 	if (blocks_count && ext4_blocks_count(es) > blocks_count) {
3685 		ext4_msg(sb, KERN_WARNING, "bad geometry: block count %llu "
3686 		       "exceeds size of device (%llu blocks)",
3687 		       ext4_blocks_count(es), blocks_count);
3688 		goto failed_mount;
3689 	}
3690 
3691 	/*
3692 	 * It makes no sense for the first data block to be beyond the end
3693 	 * of the filesystem.
3694 	 */
3695 	if (le32_to_cpu(es->s_first_data_block) >= ext4_blocks_count(es)) {
3696 		ext4_msg(sb, KERN_WARNING, "bad geometry: first data "
3697 			 "block %u is beyond end of filesystem (%llu)",
3698 			 le32_to_cpu(es->s_first_data_block),
3699 			 ext4_blocks_count(es));
3700 		goto failed_mount;
3701 	}
3702 	blocks_count = (ext4_blocks_count(es) -
3703 			le32_to_cpu(es->s_first_data_block) +
3704 			EXT4_BLOCKS_PER_GROUP(sb) - 1);
3705 	do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
3706 	if (blocks_count > ((uint64_t)1<<32) - EXT4_DESC_PER_BLOCK(sb)) {
3707 		ext4_msg(sb, KERN_WARNING, "groups count too large: %u "
3708 		       "(block count %llu, first data block %u, "
3709 		       "blocks per group %lu)", sbi->s_groups_count,
3710 		       ext4_blocks_count(es),
3711 		       le32_to_cpu(es->s_first_data_block),
3712 		       EXT4_BLOCKS_PER_GROUP(sb));
3713 		goto failed_mount;
3714 	}
3715 	sbi->s_groups_count = blocks_count;
3716 	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
3717 			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
3718 	db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
3719 		   EXT4_DESC_PER_BLOCK(sb);
3720 	sbi->s_group_desc = ext4_kvmalloc(db_count *
3721 					  sizeof(struct buffer_head *),
3722 					  GFP_KERNEL);
3723 	if (sbi->s_group_desc == NULL) {
3724 		ext4_msg(sb, KERN_ERR, "not enough memory");
3725 		ret = -ENOMEM;
3726 		goto failed_mount;
3727 	}
3728 
3729 	if (ext4_proc_root)
3730 		sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
3731 
3732 	if (sbi->s_proc)
3733 		proc_create_data("options", S_IRUGO, sbi->s_proc,
3734 				 &ext4_seq_options_fops, sb);
3735 
3736 	bgl_lock_init(sbi->s_blockgroup_lock);
3737 
3738 	for (i = 0; i < db_count; i++) {
3739 		block = descriptor_loc(sb, logical_sb_block, i);
3740 		sbi->s_group_desc[i] = sb_bread(sb, block);
3741 		if (!sbi->s_group_desc[i]) {
3742 			ext4_msg(sb, KERN_ERR,
3743 			       "can't read group descriptor %d", i);
3744 			db_count = i;
3745 			goto failed_mount2;
3746 		}
3747 	}
3748 	if (!ext4_check_descriptors(sb, &first_not_zeroed)) {
3749 		ext4_msg(sb, KERN_ERR, "group descriptors corrupted!");
3750 		goto failed_mount2;
3751 	}
3752 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
3753 		if (!ext4_fill_flex_info(sb)) {
3754 			ext4_msg(sb, KERN_ERR,
3755 			       "unable to initialize "
3756 			       "flex_bg meta info!");
3757 			goto failed_mount2;
3758 		}
3759 
3760 	sbi->s_gdb_count = db_count;
3761 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
3762 	spin_lock_init(&sbi->s_next_gen_lock);
3763 
3764 	init_timer(&sbi->s_err_report);
3765 	sbi->s_err_report.function = print_daily_error_info;
3766 	sbi->s_err_report.data = (unsigned long) sb;
3767 
3768 	/* Register extent status tree shrinker */
3769 	ext4_es_register_shrinker(sb);
3770 
3771 	err = percpu_counter_init(&sbi->s_freeclusters_counter,
3772 			ext4_count_free_clusters(sb));
3773 	if (!err) {
3774 		err = percpu_counter_init(&sbi->s_freeinodes_counter,
3775 				ext4_count_free_inodes(sb));
3776 	}
3777 	if (!err) {
3778 		err = percpu_counter_init(&sbi->s_dirs_counter,
3779 				ext4_count_dirs(sb));
3780 	}
3781 	if (!err) {
3782 		err = percpu_counter_init(&sbi->s_dirtyclusters_counter, 0);
3783 	}
3784 	if (!err) {
3785 		err = percpu_counter_init(&sbi->s_extent_cache_cnt, 0);
3786 	}
3787 	if (err) {
3788 		ext4_msg(sb, KERN_ERR, "insufficient memory");
3789 		goto failed_mount3;
3790 	}
3791 
3792 	sbi->s_stripe = ext4_get_stripe_size(sbi);
3793 	sbi->s_max_writeback_mb_bump = 128;
3794 	sbi->s_extent_max_zeroout_kb = 32;
3795 
3796 	/*
3797 	 * set up enough so that it can read an inode
3798 	 */
3799 	if (!test_opt(sb, NOLOAD) &&
3800 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL))
3801 		sb->s_op = &ext4_sops;
3802 	else
3803 		sb->s_op = &ext4_nojournal_sops;
3804 	sb->s_export_op = &ext4_export_ops;
3805 	sb->s_xattr = ext4_xattr_handlers;
3806 #ifdef CONFIG_QUOTA
3807 	sb->dq_op = &ext4_quota_operations;
3808 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA))
3809 		sb->s_qcop = &ext4_qctl_sysfile_operations;
3810 	else
3811 		sb->s_qcop = &ext4_qctl_operations;
3812 #endif
3813 	memcpy(sb->s_uuid, es->s_uuid, sizeof(es->s_uuid));
3814 
3815 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
3816 	mutex_init(&sbi->s_orphan_lock);
3817 
3818 	sb->s_root = NULL;
3819 
3820 	needs_recovery = (es->s_last_orphan != 0 ||
3821 			  EXT4_HAS_INCOMPAT_FEATURE(sb,
3822 				    EXT4_FEATURE_INCOMPAT_RECOVER));
3823 
3824 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_MMP) &&
3825 	    !(sb->s_flags & MS_RDONLY))
3826 		if (ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block)))
3827 			goto failed_mount3;
3828 
3829 	/*
3830 	 * The first inode we look at is the journal inode.  Don't try
3831 	 * root first: it may be modified in the journal!
3832 	 */
3833 	if (!test_opt(sb, NOLOAD) &&
3834 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
3835 		if (ext4_load_journal(sb, es, journal_devnum))
3836 			goto failed_mount3;
3837 	} else if (test_opt(sb, NOLOAD) && !(sb->s_flags & MS_RDONLY) &&
3838 	      EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
3839 		ext4_msg(sb, KERN_ERR, "required journal recovery "
3840 		       "suppressed and not mounted read-only");
3841 		goto failed_mount_wq;
3842 	} else {
3843 		clear_opt(sb, DATA_FLAGS);
3844 		sbi->s_journal = NULL;
3845 		needs_recovery = 0;
3846 		goto no_journal;
3847 	}
3848 
3849 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT) &&
3850 	    !jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
3851 				       JBD2_FEATURE_INCOMPAT_64BIT)) {
3852 		ext4_msg(sb, KERN_ERR, "Failed to set 64-bit journal feature");
3853 		goto failed_mount_wq;
3854 	}
3855 
3856 	if (!set_journal_csum_feature_set(sb)) {
3857 		ext4_msg(sb, KERN_ERR, "Failed to set journal checksum "
3858 			 "feature set");
3859 		goto failed_mount_wq;
3860 	}
3861 
3862 	/* We have now updated the journal if required, so we can
3863 	 * validate the data journaling mode. */
3864 	switch (test_opt(sb, DATA_FLAGS)) {
3865 	case 0:
3866 		/* No mode set, assume a default based on the journal
3867 		 * capabilities: ORDERED_DATA if the journal can
3868 		 * cope, else JOURNAL_DATA
3869 		 */
3870 		if (jbd2_journal_check_available_features
3871 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE))
3872 			set_opt(sb, ORDERED_DATA);
3873 		else
3874 			set_opt(sb, JOURNAL_DATA);
3875 		break;
3876 
3877 	case EXT4_MOUNT_ORDERED_DATA:
3878 	case EXT4_MOUNT_WRITEBACK_DATA:
3879 		if (!jbd2_journal_check_available_features
3880 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
3881 			ext4_msg(sb, KERN_ERR, "Journal does not support "
3882 			       "requested data journaling mode");
3883 			goto failed_mount_wq;
3884 		}
3885 	default:
3886 		break;
3887 	}
3888 	set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
3889 
3890 	sbi->s_journal->j_commit_callback = ext4_journal_commit_callback;
3891 
3892 	/*
3893 	 * The journal may have updated the bg summary counts, so we
3894 	 * need to update the global counters.
3895 	 */
3896 	percpu_counter_set(&sbi->s_freeclusters_counter,
3897 			   ext4_count_free_clusters(sb));
3898 	percpu_counter_set(&sbi->s_freeinodes_counter,
3899 			   ext4_count_free_inodes(sb));
3900 	percpu_counter_set(&sbi->s_dirs_counter,
3901 			   ext4_count_dirs(sb));
3902 	percpu_counter_set(&sbi->s_dirtyclusters_counter, 0);
3903 
3904 no_journal:
3905 	/*
3906 	 * Get the # of file system overhead blocks from the
3907 	 * superblock if present.
3908 	 */
3909 	if (es->s_overhead_clusters)
3910 		sbi->s_overhead = le32_to_cpu(es->s_overhead_clusters);
3911 	else {
3912 		err = ext4_calculate_overhead(sb);
3913 		if (err)
3914 			goto failed_mount_wq;
3915 	}
3916 
3917 	/*
3918 	 * The maximum number of concurrent works can be high and
3919 	 * concurrency isn't really necessary.  Limit it to 1.
3920 	 */
3921 	EXT4_SB(sb)->dio_unwritten_wq =
3922 		alloc_workqueue("ext4-dio-unwritten", WQ_MEM_RECLAIM | WQ_UNBOUND, 1);
3923 	if (!EXT4_SB(sb)->dio_unwritten_wq) {
3924 		printk(KERN_ERR "EXT4-fs: failed to create DIO workqueue\n");
3925 		ret = -ENOMEM;
3926 		goto failed_mount_wq;
3927 	}
3928 
3929 	/*
3930 	 * The jbd2_journal_load will have done any necessary log recovery,
3931 	 * so we can safely mount the rest of the filesystem now.
3932 	 */
3933 
3934 	root = ext4_iget(sb, EXT4_ROOT_INO);
3935 	if (IS_ERR(root)) {
3936 		ext4_msg(sb, KERN_ERR, "get root inode failed");
3937 		ret = PTR_ERR(root);
3938 		root = NULL;
3939 		goto failed_mount4;
3940 	}
3941 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
3942 		ext4_msg(sb, KERN_ERR, "corrupt root inode, run e2fsck");
3943 		iput(root);
3944 		goto failed_mount4;
3945 	}
3946 	sb->s_root = d_make_root(root);
3947 	if (!sb->s_root) {
3948 		ext4_msg(sb, KERN_ERR, "get root dentry failed");
3949 		ret = -ENOMEM;
3950 		goto failed_mount4;
3951 	}
3952 
3953 	if (ext4_setup_super(sb, es, sb->s_flags & MS_RDONLY))
3954 		sb->s_flags |= MS_RDONLY;
3955 
3956 	/* determine the minimum size of new large inodes, if present */
3957 	if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
3958 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
3959 						     EXT4_GOOD_OLD_INODE_SIZE;
3960 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3961 				       EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE)) {
3962 			if (sbi->s_want_extra_isize <
3963 			    le16_to_cpu(es->s_want_extra_isize))
3964 				sbi->s_want_extra_isize =
3965 					le16_to_cpu(es->s_want_extra_isize);
3966 			if (sbi->s_want_extra_isize <
3967 			    le16_to_cpu(es->s_min_extra_isize))
3968 				sbi->s_want_extra_isize =
3969 					le16_to_cpu(es->s_min_extra_isize);
3970 		}
3971 	}
3972 	/* Check if enough inode space is available */
3973 	if (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize >
3974 							sbi->s_inode_size) {
3975 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
3976 						       EXT4_GOOD_OLD_INODE_SIZE;
3977 		ext4_msg(sb, KERN_INFO, "required extra inode space not"
3978 			 "available");
3979 	}
3980 
3981 	err = ext4_reserve_clusters(sbi, ext4_calculate_resv_clusters(sbi));
3982 	if (err) {
3983 		ext4_msg(sb, KERN_ERR, "failed to reserve %llu clusters for "
3984 			 "reserved pool", ext4_calculate_resv_clusters(sbi));
3985 		goto failed_mount4a;
3986 	}
3987 
3988 	err = ext4_setup_system_zone(sb);
3989 	if (err) {
3990 		ext4_msg(sb, KERN_ERR, "failed to initialize system "
3991 			 "zone (%d)", err);
3992 		goto failed_mount4a;
3993 	}
3994 
3995 	ext4_ext_init(sb);
3996 	err = ext4_mb_init(sb);
3997 	if (err) {
3998 		ext4_msg(sb, KERN_ERR, "failed to initialize mballoc (%d)",
3999 			 err);
4000 		goto failed_mount5;
4001 	}
4002 
4003 	err = ext4_register_li_request(sb, first_not_zeroed);
4004 	if (err)
4005 		goto failed_mount6;
4006 
4007 	sbi->s_kobj.kset = ext4_kset;
4008 	init_completion(&sbi->s_kobj_unregister);
4009 	err = kobject_init_and_add(&sbi->s_kobj, &ext4_ktype, NULL,
4010 				   "%s", sb->s_id);
4011 	if (err)
4012 		goto failed_mount7;
4013 
4014 #ifdef CONFIG_QUOTA
4015 	/* Enable quota usage during mount. */
4016 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA) &&
4017 	    !(sb->s_flags & MS_RDONLY)) {
4018 		err = ext4_enable_quotas(sb);
4019 		if (err)
4020 			goto failed_mount8;
4021 	}
4022 #endif  /* CONFIG_QUOTA */
4023 
4024 	EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
4025 	ext4_orphan_cleanup(sb, es);
4026 	EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
4027 	if (needs_recovery) {
4028 		ext4_msg(sb, KERN_INFO, "recovery complete");
4029 		ext4_mark_recovery_complete(sb, es);
4030 	}
4031 	if (EXT4_SB(sb)->s_journal) {
4032 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
4033 			descr = " journalled data mode";
4034 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
4035 			descr = " ordered data mode";
4036 		else
4037 			descr = " writeback data mode";
4038 	} else
4039 		descr = "out journal";
4040 
4041 	if (test_opt(sb, DISCARD)) {
4042 		struct request_queue *q = bdev_get_queue(sb->s_bdev);
4043 		if (!blk_queue_discard(q))
4044 			ext4_msg(sb, KERN_WARNING,
4045 				 "mounting with \"discard\" option, but "
4046 				 "the device does not support discard");
4047 	}
4048 
4049 	ext4_msg(sb, KERN_INFO, "mounted filesystem with%s. "
4050 		 "Opts: %s%s%s", descr, sbi->s_es->s_mount_opts,
4051 		 *sbi->s_es->s_mount_opts ? "; " : "", orig_data);
4052 
4053 	if (es->s_error_count)
4054 		mod_timer(&sbi->s_err_report, jiffies + 300*HZ); /* 5 minutes */
4055 
4056 	kfree(orig_data);
4057 	return 0;
4058 
4059 cantfind_ext4:
4060 	if (!silent)
4061 		ext4_msg(sb, KERN_ERR, "VFS: Can't find ext4 filesystem");
4062 	goto failed_mount;
4063 
4064 #ifdef CONFIG_QUOTA
4065 failed_mount8:
4066 	kobject_del(&sbi->s_kobj);
4067 #endif
4068 failed_mount7:
4069 	ext4_unregister_li_request(sb);
4070 failed_mount6:
4071 	ext4_mb_release(sb);
4072 failed_mount5:
4073 	ext4_ext_release(sb);
4074 	ext4_release_system_zone(sb);
4075 failed_mount4a:
4076 	dput(sb->s_root);
4077 	sb->s_root = NULL;
4078 failed_mount4:
4079 	ext4_msg(sb, KERN_ERR, "mount failed");
4080 	destroy_workqueue(EXT4_SB(sb)->dio_unwritten_wq);
4081 failed_mount_wq:
4082 	if (sbi->s_journal) {
4083 		jbd2_journal_destroy(sbi->s_journal);
4084 		sbi->s_journal = NULL;
4085 	}
4086 failed_mount3:
4087 	ext4_es_unregister_shrinker(sb);
4088 	del_timer(&sbi->s_err_report);
4089 	if (sbi->s_flex_groups)
4090 		ext4_kvfree(sbi->s_flex_groups);
4091 	percpu_counter_destroy(&sbi->s_freeclusters_counter);
4092 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
4093 	percpu_counter_destroy(&sbi->s_dirs_counter);
4094 	percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
4095 	percpu_counter_destroy(&sbi->s_extent_cache_cnt);
4096 	if (sbi->s_mmp_tsk)
4097 		kthread_stop(sbi->s_mmp_tsk);
4098 failed_mount2:
4099 	for (i = 0; i < db_count; i++)
4100 		brelse(sbi->s_group_desc[i]);
4101 	ext4_kvfree(sbi->s_group_desc);
4102 failed_mount:
4103 	if (sbi->s_chksum_driver)
4104 		crypto_free_shash(sbi->s_chksum_driver);
4105 	if (sbi->s_proc) {
4106 		remove_proc_entry("options", sbi->s_proc);
4107 		remove_proc_entry(sb->s_id, ext4_proc_root);
4108 	}
4109 #ifdef CONFIG_QUOTA
4110 	for (i = 0; i < MAXQUOTAS; i++)
4111 		kfree(sbi->s_qf_names[i]);
4112 #endif
4113 	ext4_blkdev_remove(sbi);
4114 	brelse(bh);
4115 out_fail:
4116 	sb->s_fs_info = NULL;
4117 	kfree(sbi->s_blockgroup_lock);
4118 	kfree(sbi);
4119 out_free_orig:
4120 	kfree(orig_data);
4121 	return err ? err : ret;
4122 }
4123 
4124 /*
4125  * Setup any per-fs journal parameters now.  We'll do this both on
4126  * initial mount, once the journal has been initialised but before we've
4127  * done any recovery; and again on any subsequent remount.
4128  */
4129 static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
4130 {
4131 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4132 
4133 	journal->j_commit_interval = sbi->s_commit_interval;
4134 	journal->j_min_batch_time = sbi->s_min_batch_time;
4135 	journal->j_max_batch_time = sbi->s_max_batch_time;
4136 
4137 	write_lock(&journal->j_state_lock);
4138 	if (test_opt(sb, BARRIER))
4139 		journal->j_flags |= JBD2_BARRIER;
4140 	else
4141 		journal->j_flags &= ~JBD2_BARRIER;
4142 	if (test_opt(sb, DATA_ERR_ABORT))
4143 		journal->j_flags |= JBD2_ABORT_ON_SYNCDATA_ERR;
4144 	else
4145 		journal->j_flags &= ~JBD2_ABORT_ON_SYNCDATA_ERR;
4146 	write_unlock(&journal->j_state_lock);
4147 }
4148 
4149 static journal_t *ext4_get_journal(struct super_block *sb,
4150 				   unsigned int journal_inum)
4151 {
4152 	struct inode *journal_inode;
4153 	journal_t *journal;
4154 
4155 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4156 
4157 	/* First, test for the existence of a valid inode on disk.  Bad
4158 	 * things happen if we iget() an unused inode, as the subsequent
4159 	 * iput() will try to delete it. */
4160 
4161 	journal_inode = ext4_iget(sb, journal_inum);
4162 	if (IS_ERR(journal_inode)) {
4163 		ext4_msg(sb, KERN_ERR, "no journal found");
4164 		return NULL;
4165 	}
4166 	if (!journal_inode->i_nlink) {
4167 		make_bad_inode(journal_inode);
4168 		iput(journal_inode);
4169 		ext4_msg(sb, KERN_ERR, "journal inode is deleted");
4170 		return NULL;
4171 	}
4172 
4173 	jbd_debug(2, "Journal inode found at %p: %lld bytes\n",
4174 		  journal_inode, journal_inode->i_size);
4175 	if (!S_ISREG(journal_inode->i_mode)) {
4176 		ext4_msg(sb, KERN_ERR, "invalid journal inode");
4177 		iput(journal_inode);
4178 		return NULL;
4179 	}
4180 
4181 	journal = jbd2_journal_init_inode(journal_inode);
4182 	if (!journal) {
4183 		ext4_msg(sb, KERN_ERR, "Could not load journal inode");
4184 		iput(journal_inode);
4185 		return NULL;
4186 	}
4187 	journal->j_private = sb;
4188 	ext4_init_journal_params(sb, journal);
4189 	return journal;
4190 }
4191 
4192 static journal_t *ext4_get_dev_journal(struct super_block *sb,
4193 				       dev_t j_dev)
4194 {
4195 	struct buffer_head *bh;
4196 	journal_t *journal;
4197 	ext4_fsblk_t start;
4198 	ext4_fsblk_t len;
4199 	int hblock, blocksize;
4200 	ext4_fsblk_t sb_block;
4201 	unsigned long offset;
4202 	struct ext4_super_block *es;
4203 	struct block_device *bdev;
4204 
4205 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4206 
4207 	bdev = ext4_blkdev_get(j_dev, sb);
4208 	if (bdev == NULL)
4209 		return NULL;
4210 
4211 	blocksize = sb->s_blocksize;
4212 	hblock = bdev_logical_block_size(bdev);
4213 	if (blocksize < hblock) {
4214 		ext4_msg(sb, KERN_ERR,
4215 			"blocksize too small for journal device");
4216 		goto out_bdev;
4217 	}
4218 
4219 	sb_block = EXT4_MIN_BLOCK_SIZE / blocksize;
4220 	offset = EXT4_MIN_BLOCK_SIZE % blocksize;
4221 	set_blocksize(bdev, blocksize);
4222 	if (!(bh = __bread(bdev, sb_block, blocksize))) {
4223 		ext4_msg(sb, KERN_ERR, "couldn't read superblock of "
4224 		       "external journal");
4225 		goto out_bdev;
4226 	}
4227 
4228 	es = (struct ext4_super_block *) (bh->b_data + offset);
4229 	if ((le16_to_cpu(es->s_magic) != EXT4_SUPER_MAGIC) ||
4230 	    !(le32_to_cpu(es->s_feature_incompat) &
4231 	      EXT4_FEATURE_INCOMPAT_JOURNAL_DEV)) {
4232 		ext4_msg(sb, KERN_ERR, "external journal has "
4233 					"bad superblock");
4234 		brelse(bh);
4235 		goto out_bdev;
4236 	}
4237 
4238 	if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
4239 		ext4_msg(sb, KERN_ERR, "journal UUID does not match");
4240 		brelse(bh);
4241 		goto out_bdev;
4242 	}
4243 
4244 	len = ext4_blocks_count(es);
4245 	start = sb_block + 1;
4246 	brelse(bh);	/* we're done with the superblock */
4247 
4248 	journal = jbd2_journal_init_dev(bdev, sb->s_bdev,
4249 					start, len, blocksize);
4250 	if (!journal) {
4251 		ext4_msg(sb, KERN_ERR, "failed to create device journal");
4252 		goto out_bdev;
4253 	}
4254 	journal->j_private = sb;
4255 	ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &journal->j_sb_buffer);
4256 	wait_on_buffer(journal->j_sb_buffer);
4257 	if (!buffer_uptodate(journal->j_sb_buffer)) {
4258 		ext4_msg(sb, KERN_ERR, "I/O error on journal device");
4259 		goto out_journal;
4260 	}
4261 	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
4262 		ext4_msg(sb, KERN_ERR, "External journal has more than one "
4263 					"user (unsupported) - %d",
4264 			be32_to_cpu(journal->j_superblock->s_nr_users));
4265 		goto out_journal;
4266 	}
4267 	EXT4_SB(sb)->journal_bdev = bdev;
4268 	ext4_init_journal_params(sb, journal);
4269 	return journal;
4270 
4271 out_journal:
4272 	jbd2_journal_destroy(journal);
4273 out_bdev:
4274 	ext4_blkdev_put(bdev);
4275 	return NULL;
4276 }
4277 
4278 static int ext4_load_journal(struct super_block *sb,
4279 			     struct ext4_super_block *es,
4280 			     unsigned long journal_devnum)
4281 {
4282 	journal_t *journal;
4283 	unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
4284 	dev_t journal_dev;
4285 	int err = 0;
4286 	int really_read_only;
4287 
4288 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4289 
4290 	if (journal_devnum &&
4291 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
4292 		ext4_msg(sb, KERN_INFO, "external journal device major/minor "
4293 			"numbers have changed");
4294 		journal_dev = new_decode_dev(journal_devnum);
4295 	} else
4296 		journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));
4297 
4298 	really_read_only = bdev_read_only(sb->s_bdev);
4299 
4300 	/*
4301 	 * Are we loading a blank journal or performing recovery after a
4302 	 * crash?  For recovery, we need to check in advance whether we
4303 	 * can get read-write access to the device.
4304 	 */
4305 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
4306 		if (sb->s_flags & MS_RDONLY) {
4307 			ext4_msg(sb, KERN_INFO, "INFO: recovery "
4308 					"required on readonly filesystem");
4309 			if (really_read_only) {
4310 				ext4_msg(sb, KERN_ERR, "write access "
4311 					"unavailable, cannot proceed");
4312 				return -EROFS;
4313 			}
4314 			ext4_msg(sb, KERN_INFO, "write access will "
4315 			       "be enabled during recovery");
4316 		}
4317 	}
4318 
4319 	if (journal_inum && journal_dev) {
4320 		ext4_msg(sb, KERN_ERR, "filesystem has both journal "
4321 		       "and inode journals!");
4322 		return -EINVAL;
4323 	}
4324 
4325 	if (journal_inum) {
4326 		if (!(journal = ext4_get_journal(sb, journal_inum)))
4327 			return -EINVAL;
4328 	} else {
4329 		if (!(journal = ext4_get_dev_journal(sb, journal_dev)))
4330 			return -EINVAL;
4331 	}
4332 
4333 	if (!(journal->j_flags & JBD2_BARRIER))
4334 		ext4_msg(sb, KERN_INFO, "barriers disabled");
4335 
4336 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER))
4337 		err = jbd2_journal_wipe(journal, !really_read_only);
4338 	if (!err) {
4339 		char *save = kmalloc(EXT4_S_ERR_LEN, GFP_KERNEL);
4340 		if (save)
4341 			memcpy(save, ((char *) es) +
4342 			       EXT4_S_ERR_START, EXT4_S_ERR_LEN);
4343 		err = jbd2_journal_load(journal);
4344 		if (save)
4345 			memcpy(((char *) es) + EXT4_S_ERR_START,
4346 			       save, EXT4_S_ERR_LEN);
4347 		kfree(save);
4348 	}
4349 
4350 	if (err) {
4351 		ext4_msg(sb, KERN_ERR, "error loading journal");
4352 		jbd2_journal_destroy(journal);
4353 		return err;
4354 	}
4355 
4356 	EXT4_SB(sb)->s_journal = journal;
4357 	ext4_clear_journal_err(sb, es);
4358 
4359 	if (!really_read_only && journal_devnum &&
4360 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
4361 		es->s_journal_dev = cpu_to_le32(journal_devnum);
4362 
4363 		/* Make sure we flush the recovery flag to disk. */
4364 		ext4_commit_super(sb, 1);
4365 	}
4366 
4367 	return 0;
4368 }
4369 
4370 static int ext4_commit_super(struct super_block *sb, int sync)
4371 {
4372 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
4373 	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
4374 	int error = 0;
4375 
4376 	if (!sbh || block_device_ejected(sb))
4377 		return error;
4378 	if (buffer_write_io_error(sbh)) {
4379 		/*
4380 		 * Oh, dear.  A previous attempt to write the
4381 		 * superblock failed.  This could happen because the
4382 		 * USB device was yanked out.  Or it could happen to
4383 		 * be a transient write error and maybe the block will
4384 		 * be remapped.  Nothing we can do but to retry the
4385 		 * write and hope for the best.
4386 		 */
4387 		ext4_msg(sb, KERN_ERR, "previous I/O error to "
4388 		       "superblock detected");
4389 		clear_buffer_write_io_error(sbh);
4390 		set_buffer_uptodate(sbh);
4391 	}
4392 	/*
4393 	 * If the file system is mounted read-only, don't update the
4394 	 * superblock write time.  This avoids updating the superblock
4395 	 * write time when we are mounting the root file system
4396 	 * read/only but we need to replay the journal; at that point,
4397 	 * for people who are east of GMT and who make their clock
4398 	 * tick in localtime for Windows bug-for-bug compatibility,
4399 	 * the clock is set in the future, and this will cause e2fsck
4400 	 * to complain and force a full file system check.
4401 	 */
4402 	if (!(sb->s_flags & MS_RDONLY))
4403 		es->s_wtime = cpu_to_le32(get_seconds());
4404 	if (sb->s_bdev->bd_part)
4405 		es->s_kbytes_written =
4406 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written +
4407 			    ((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
4408 			      EXT4_SB(sb)->s_sectors_written_start) >> 1));
4409 	else
4410 		es->s_kbytes_written =
4411 			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written);
4412 	ext4_free_blocks_count_set(es,
4413 			EXT4_C2B(EXT4_SB(sb), percpu_counter_sum_positive(
4414 				&EXT4_SB(sb)->s_freeclusters_counter)));
4415 	es->s_free_inodes_count =
4416 		cpu_to_le32(percpu_counter_sum_positive(
4417 				&EXT4_SB(sb)->s_freeinodes_counter));
4418 	BUFFER_TRACE(sbh, "marking dirty");
4419 	ext4_superblock_csum_set(sb);
4420 	mark_buffer_dirty(sbh);
4421 	if (sync) {
4422 		error = sync_dirty_buffer(sbh);
4423 		if (error)
4424 			return error;
4425 
4426 		error = buffer_write_io_error(sbh);
4427 		if (error) {
4428 			ext4_msg(sb, KERN_ERR, "I/O error while writing "
4429 			       "superblock");
4430 			clear_buffer_write_io_error(sbh);
4431 			set_buffer_uptodate(sbh);
4432 		}
4433 	}
4434 	return error;
4435 }
4436 
4437 /*
4438  * Have we just finished recovery?  If so, and if we are mounting (or
4439  * remounting) the filesystem readonly, then we will end up with a
4440  * consistent fs on disk.  Record that fact.
4441  */
4442 static void ext4_mark_recovery_complete(struct super_block *sb,
4443 					struct ext4_super_block *es)
4444 {
4445 	journal_t *journal = EXT4_SB(sb)->s_journal;
4446 
4447 	if (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
4448 		BUG_ON(journal != NULL);
4449 		return;
4450 	}
4451 	jbd2_journal_lock_updates(journal);
4452 	if (jbd2_journal_flush(journal) < 0)
4453 		goto out;
4454 
4455 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER) &&
4456 	    sb->s_flags & MS_RDONLY) {
4457 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4458 		ext4_commit_super(sb, 1);
4459 	}
4460 
4461 out:
4462 	jbd2_journal_unlock_updates(journal);
4463 }
4464 
4465 /*
4466  * If we are mounting (or read-write remounting) a filesystem whose journal
4467  * has recorded an error from a previous lifetime, move that error to the
4468  * main filesystem now.
4469  */
4470 static void ext4_clear_journal_err(struct super_block *sb,
4471 				   struct ext4_super_block *es)
4472 {
4473 	journal_t *journal;
4474 	int j_errno;
4475 	const char *errstr;
4476 
4477 	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
4478 
4479 	journal = EXT4_SB(sb)->s_journal;
4480 
4481 	/*
4482 	 * Now check for any error status which may have been recorded in the
4483 	 * journal by a prior ext4_error() or ext4_abort()
4484 	 */
4485 
4486 	j_errno = jbd2_journal_errno(journal);
4487 	if (j_errno) {
4488 		char nbuf[16];
4489 
4490 		errstr = ext4_decode_error(sb, j_errno, nbuf);
4491 		ext4_warning(sb, "Filesystem error recorded "
4492 			     "from previous mount: %s", errstr);
4493 		ext4_warning(sb, "Marking fs in need of filesystem check.");
4494 
4495 		EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
4496 		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
4497 		ext4_commit_super(sb, 1);
4498 
4499 		jbd2_journal_clear_err(journal);
4500 		jbd2_journal_update_sb_errno(journal);
4501 	}
4502 }
4503 
4504 /*
4505  * Force the running and committing transactions to commit,
4506  * and wait on the commit.
4507  */
4508 int ext4_force_commit(struct super_block *sb)
4509 {
4510 	journal_t *journal;
4511 
4512 	if (sb->s_flags & MS_RDONLY)
4513 		return 0;
4514 
4515 	journal = EXT4_SB(sb)->s_journal;
4516 	return ext4_journal_force_commit(journal);
4517 }
4518 
4519 static int ext4_sync_fs(struct super_block *sb, int wait)
4520 {
4521 	int ret = 0;
4522 	tid_t target;
4523 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4524 
4525 	trace_ext4_sync_fs(sb, wait);
4526 	flush_workqueue(sbi->dio_unwritten_wq);
4527 	/*
4528 	 * Writeback quota in non-journalled quota case - journalled quota has
4529 	 * no dirty dquots
4530 	 */
4531 	dquot_writeback_dquots(sb, -1);
4532 	if (jbd2_journal_start_commit(sbi->s_journal, &target)) {
4533 		if (wait)
4534 			jbd2_log_wait_commit(sbi->s_journal, target);
4535 	}
4536 	return ret;
4537 }
4538 
4539 /*
4540  * LVM calls this function before a (read-only) snapshot is created.  This
4541  * gives us a chance to flush the journal completely and mark the fs clean.
4542  *
4543  * Note that only this function cannot bring a filesystem to be in a clean
4544  * state independently. It relies on upper layer to stop all data & metadata
4545  * modifications.
4546  */
4547 static int ext4_freeze(struct super_block *sb)
4548 {
4549 	int error = 0;
4550 	journal_t *journal;
4551 
4552 	if (sb->s_flags & MS_RDONLY)
4553 		return 0;
4554 
4555 	journal = EXT4_SB(sb)->s_journal;
4556 
4557 	/* Now we set up the journal barrier. */
4558 	jbd2_journal_lock_updates(journal);
4559 
4560 	/*
4561 	 * Don't clear the needs_recovery flag if we failed to flush
4562 	 * the journal.
4563 	 */
4564 	error = jbd2_journal_flush(journal);
4565 	if (error < 0)
4566 		goto out;
4567 
4568 	/* Journal blocked and flushed, clear needs_recovery flag. */
4569 	EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4570 	error = ext4_commit_super(sb, 1);
4571 out:
4572 	/* we rely on upper layer to stop further updates */
4573 	jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
4574 	return error;
4575 }
4576 
4577 /*
4578  * Called by LVM after the snapshot is done.  We need to reset the RECOVER
4579  * flag here, even though the filesystem is not technically dirty yet.
4580  */
4581 static int ext4_unfreeze(struct super_block *sb)
4582 {
4583 	if (sb->s_flags & MS_RDONLY)
4584 		return 0;
4585 
4586 	/* Reset the needs_recovery flag before the fs is unlocked. */
4587 	EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
4588 	ext4_commit_super(sb, 1);
4589 	return 0;
4590 }
4591 
4592 /*
4593  * Structure to save mount options for ext4_remount's benefit
4594  */
4595 struct ext4_mount_options {
4596 	unsigned long s_mount_opt;
4597 	unsigned long s_mount_opt2;
4598 	kuid_t s_resuid;
4599 	kgid_t s_resgid;
4600 	unsigned long s_commit_interval;
4601 	u32 s_min_batch_time, s_max_batch_time;
4602 #ifdef CONFIG_QUOTA
4603 	int s_jquota_fmt;
4604 	char *s_qf_names[MAXQUOTAS];
4605 #endif
4606 };
4607 
4608 static int ext4_remount(struct super_block *sb, int *flags, char *data)
4609 {
4610 	struct ext4_super_block *es;
4611 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4612 	unsigned long old_sb_flags;
4613 	struct ext4_mount_options old_opts;
4614 	int enable_quota = 0;
4615 	ext4_group_t g;
4616 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
4617 	int err = 0;
4618 #ifdef CONFIG_QUOTA
4619 	int i, j;
4620 #endif
4621 	char *orig_data = kstrdup(data, GFP_KERNEL);
4622 
4623 	/* Store the original options */
4624 	old_sb_flags = sb->s_flags;
4625 	old_opts.s_mount_opt = sbi->s_mount_opt;
4626 	old_opts.s_mount_opt2 = sbi->s_mount_opt2;
4627 	old_opts.s_resuid = sbi->s_resuid;
4628 	old_opts.s_resgid = sbi->s_resgid;
4629 	old_opts.s_commit_interval = sbi->s_commit_interval;
4630 	old_opts.s_min_batch_time = sbi->s_min_batch_time;
4631 	old_opts.s_max_batch_time = sbi->s_max_batch_time;
4632 #ifdef CONFIG_QUOTA
4633 	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
4634 	for (i = 0; i < MAXQUOTAS; i++)
4635 		if (sbi->s_qf_names[i]) {
4636 			old_opts.s_qf_names[i] = kstrdup(sbi->s_qf_names[i],
4637 							 GFP_KERNEL);
4638 			if (!old_opts.s_qf_names[i]) {
4639 				for (j = 0; j < i; j++)
4640 					kfree(old_opts.s_qf_names[j]);
4641 				kfree(orig_data);
4642 				return -ENOMEM;
4643 			}
4644 		} else
4645 			old_opts.s_qf_names[i] = NULL;
4646 #endif
4647 	if (sbi->s_journal && sbi->s_journal->j_task->io_context)
4648 		journal_ioprio = sbi->s_journal->j_task->io_context->ioprio;
4649 
4650 	/*
4651 	 * Allow the "check" option to be passed as a remount option.
4652 	 */
4653 	if (!parse_options(data, sb, NULL, &journal_ioprio, 1)) {
4654 		err = -EINVAL;
4655 		goto restore_opts;
4656 	}
4657 
4658 	if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
4659 		ext4_abort(sb, "Abort forced by user");
4660 
4661 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
4662 		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
4663 
4664 	es = sbi->s_es;
4665 
4666 	if (sbi->s_journal) {
4667 		ext4_init_journal_params(sb, sbi->s_journal);
4668 		set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
4669 	}
4670 
4671 	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY)) {
4672 		if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) {
4673 			err = -EROFS;
4674 			goto restore_opts;
4675 		}
4676 
4677 		if (*flags & MS_RDONLY) {
4678 			err = dquot_suspend(sb, -1);
4679 			if (err < 0)
4680 				goto restore_opts;
4681 
4682 			/*
4683 			 * First of all, the unconditional stuff we have to do
4684 			 * to disable replay of the journal when we next remount
4685 			 */
4686 			sb->s_flags |= MS_RDONLY;
4687 
4688 			/*
4689 			 * OK, test if we are remounting a valid rw partition
4690 			 * readonly, and if so set the rdonly flag and then
4691 			 * mark the partition as valid again.
4692 			 */
4693 			if (!(es->s_state & cpu_to_le16(EXT4_VALID_FS)) &&
4694 			    (sbi->s_mount_state & EXT4_VALID_FS))
4695 				es->s_state = cpu_to_le16(sbi->s_mount_state);
4696 
4697 			if (sbi->s_journal)
4698 				ext4_mark_recovery_complete(sb, es);
4699 		} else {
4700 			/* Make sure we can mount this feature set readwrite */
4701 			if (!ext4_feature_set_ok(sb, 0)) {
4702 				err = -EROFS;
4703 				goto restore_opts;
4704 			}
4705 			/*
4706 			 * Make sure the group descriptor checksums
4707 			 * are sane.  If they aren't, refuse to remount r/w.
4708 			 */
4709 			for (g = 0; g < sbi->s_groups_count; g++) {
4710 				struct ext4_group_desc *gdp =
4711 					ext4_get_group_desc(sb, g, NULL);
4712 
4713 				if (!ext4_group_desc_csum_verify(sb, g, gdp)) {
4714 					ext4_msg(sb, KERN_ERR,
4715 	       "ext4_remount: Checksum for group %u failed (%u!=%u)",
4716 		g, le16_to_cpu(ext4_group_desc_csum(sbi, g, gdp)),
4717 					       le16_to_cpu(gdp->bg_checksum));
4718 					err = -EINVAL;
4719 					goto restore_opts;
4720 				}
4721 			}
4722 
4723 			/*
4724 			 * If we have an unprocessed orphan list hanging
4725 			 * around from a previously readonly bdev mount,
4726 			 * require a full umount/remount for now.
4727 			 */
4728 			if (es->s_last_orphan) {
4729 				ext4_msg(sb, KERN_WARNING, "Couldn't "
4730 				       "remount RDWR because of unprocessed "
4731 				       "orphan inode list.  Please "
4732 				       "umount/remount instead");
4733 				err = -EINVAL;
4734 				goto restore_opts;
4735 			}
4736 
4737 			/*
4738 			 * Mounting a RDONLY partition read-write, so reread
4739 			 * and store the current valid flag.  (It may have
4740 			 * been changed by e2fsck since we originally mounted
4741 			 * the partition.)
4742 			 */
4743 			if (sbi->s_journal)
4744 				ext4_clear_journal_err(sb, es);
4745 			sbi->s_mount_state = le16_to_cpu(es->s_state);
4746 			if (!ext4_setup_super(sb, es, 0))
4747 				sb->s_flags &= ~MS_RDONLY;
4748 			if (EXT4_HAS_INCOMPAT_FEATURE(sb,
4749 						     EXT4_FEATURE_INCOMPAT_MMP))
4750 				if (ext4_multi_mount_protect(sb,
4751 						le64_to_cpu(es->s_mmp_block))) {
4752 					err = -EROFS;
4753 					goto restore_opts;
4754 				}
4755 			enable_quota = 1;
4756 		}
4757 	}
4758 
4759 	/*
4760 	 * Reinitialize lazy itable initialization thread based on
4761 	 * current settings
4762 	 */
4763 	if ((sb->s_flags & MS_RDONLY) || !test_opt(sb, INIT_INODE_TABLE))
4764 		ext4_unregister_li_request(sb);
4765 	else {
4766 		ext4_group_t first_not_zeroed;
4767 		first_not_zeroed = ext4_has_uninit_itable(sb);
4768 		ext4_register_li_request(sb, first_not_zeroed);
4769 	}
4770 
4771 	ext4_setup_system_zone(sb);
4772 	if (sbi->s_journal == NULL && !(old_sb_flags & MS_RDONLY))
4773 		ext4_commit_super(sb, 1);
4774 
4775 #ifdef CONFIG_QUOTA
4776 	/* Release old quota file names */
4777 	for (i = 0; i < MAXQUOTAS; i++)
4778 		kfree(old_opts.s_qf_names[i]);
4779 	if (enable_quota) {
4780 		if (sb_any_quota_suspended(sb))
4781 			dquot_resume(sb, -1);
4782 		else if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
4783 					EXT4_FEATURE_RO_COMPAT_QUOTA)) {
4784 			err = ext4_enable_quotas(sb);
4785 			if (err)
4786 				goto restore_opts;
4787 		}
4788 	}
4789 #endif
4790 
4791 	ext4_msg(sb, KERN_INFO, "re-mounted. Opts: %s", orig_data);
4792 	kfree(orig_data);
4793 	return 0;
4794 
4795 restore_opts:
4796 	sb->s_flags = old_sb_flags;
4797 	sbi->s_mount_opt = old_opts.s_mount_opt;
4798 	sbi->s_mount_opt2 = old_opts.s_mount_opt2;
4799 	sbi->s_resuid = old_opts.s_resuid;
4800 	sbi->s_resgid = old_opts.s_resgid;
4801 	sbi->s_commit_interval = old_opts.s_commit_interval;
4802 	sbi->s_min_batch_time = old_opts.s_min_batch_time;
4803 	sbi->s_max_batch_time = old_opts.s_max_batch_time;
4804 #ifdef CONFIG_QUOTA
4805 	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
4806 	for (i = 0; i < MAXQUOTAS; i++) {
4807 		kfree(sbi->s_qf_names[i]);
4808 		sbi->s_qf_names[i] = old_opts.s_qf_names[i];
4809 	}
4810 #endif
4811 	kfree(orig_data);
4812 	return err;
4813 }
4814 
4815 static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
4816 {
4817 	struct super_block *sb = dentry->d_sb;
4818 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4819 	struct ext4_super_block *es = sbi->s_es;
4820 	ext4_fsblk_t overhead = 0, resv_blocks;
4821 	u64 fsid;
4822 	s64 bfree;
4823 	resv_blocks = EXT4_C2B(sbi, atomic64_read(&sbi->s_resv_clusters));
4824 
4825 	if (!test_opt(sb, MINIX_DF))
4826 		overhead = sbi->s_overhead;
4827 
4828 	buf->f_type = EXT4_SUPER_MAGIC;
4829 	buf->f_bsize = sb->s_blocksize;
4830 	buf->f_blocks = ext4_blocks_count(es) - EXT4_C2B(sbi, overhead);
4831 	bfree = percpu_counter_sum_positive(&sbi->s_freeclusters_counter) -
4832 		percpu_counter_sum_positive(&sbi->s_dirtyclusters_counter);
4833 	/* prevent underflow in case that few free space is available */
4834 	buf->f_bfree = EXT4_C2B(sbi, max_t(s64, bfree, 0));
4835 	buf->f_bavail = buf->f_bfree -
4836 			(ext4_r_blocks_count(es) + resv_blocks);
4837 	if (buf->f_bfree < (ext4_r_blocks_count(es) + resv_blocks))
4838 		buf->f_bavail = 0;
4839 	buf->f_files = le32_to_cpu(es->s_inodes_count);
4840 	buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter);
4841 	buf->f_namelen = EXT4_NAME_LEN;
4842 	fsid = le64_to_cpup((void *)es->s_uuid) ^
4843 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
4844 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
4845 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
4846 
4847 	return 0;
4848 }
4849 
4850 /* Helper function for writing quotas on sync - we need to start transaction
4851  * before quota file is locked for write. Otherwise the are possible deadlocks:
4852  * Process 1                         Process 2
4853  * ext4_create()                     quota_sync()
4854  *   jbd2_journal_start()                  write_dquot()
4855  *   dquot_initialize()                         down(dqio_mutex)
4856  *     down(dqio_mutex)                    jbd2_journal_start()
4857  *
4858  */
4859 
4860 #ifdef CONFIG_QUOTA
4861 
4862 static inline struct inode *dquot_to_inode(struct dquot *dquot)
4863 {
4864 	return sb_dqopt(dquot->dq_sb)->files[dquot->dq_id.type];
4865 }
4866 
4867 static int ext4_write_dquot(struct dquot *dquot)
4868 {
4869 	int ret, err;
4870 	handle_t *handle;
4871 	struct inode *inode;
4872 
4873 	inode = dquot_to_inode(dquot);
4874 	handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
4875 				    EXT4_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
4876 	if (IS_ERR(handle))
4877 		return PTR_ERR(handle);
4878 	ret = dquot_commit(dquot);
4879 	err = ext4_journal_stop(handle);
4880 	if (!ret)
4881 		ret = err;
4882 	return ret;
4883 }
4884 
4885 static int ext4_acquire_dquot(struct dquot *dquot)
4886 {
4887 	int ret, err;
4888 	handle_t *handle;
4889 
4890 	handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
4891 				    EXT4_QUOTA_INIT_BLOCKS(dquot->dq_sb));
4892 	if (IS_ERR(handle))
4893 		return PTR_ERR(handle);
4894 	ret = dquot_acquire(dquot);
4895 	err = ext4_journal_stop(handle);
4896 	if (!ret)
4897 		ret = err;
4898 	return ret;
4899 }
4900 
4901 static int ext4_release_dquot(struct dquot *dquot)
4902 {
4903 	int ret, err;
4904 	handle_t *handle;
4905 
4906 	handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
4907 				    EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
4908 	if (IS_ERR(handle)) {
4909 		/* Release dquot anyway to avoid endless cycle in dqput() */
4910 		dquot_release(dquot);
4911 		return PTR_ERR(handle);
4912 	}
4913 	ret = dquot_release(dquot);
4914 	err = ext4_journal_stop(handle);
4915 	if (!ret)
4916 		ret = err;
4917 	return ret;
4918 }
4919 
4920 static int ext4_mark_dquot_dirty(struct dquot *dquot)
4921 {
4922 	struct super_block *sb = dquot->dq_sb;
4923 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4924 
4925 	/* Are we journaling quotas? */
4926 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA) ||
4927 	    sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
4928 		dquot_mark_dquot_dirty(dquot);
4929 		return ext4_write_dquot(dquot);
4930 	} else {
4931 		return dquot_mark_dquot_dirty(dquot);
4932 	}
4933 }
4934 
4935 static int ext4_write_info(struct super_block *sb, int type)
4936 {
4937 	int ret, err;
4938 	handle_t *handle;
4939 
4940 	/* Data block + inode block */
4941 	handle = ext4_journal_start(sb->s_root->d_inode, EXT4_HT_QUOTA, 2);
4942 	if (IS_ERR(handle))
4943 		return PTR_ERR(handle);
4944 	ret = dquot_commit_info(sb, type);
4945 	err = ext4_journal_stop(handle);
4946 	if (!ret)
4947 		ret = err;
4948 	return ret;
4949 }
4950 
4951 /*
4952  * Turn on quotas during mount time - we need to find
4953  * the quota file and such...
4954  */
4955 static int ext4_quota_on_mount(struct super_block *sb, int type)
4956 {
4957 	return dquot_quota_on_mount(sb, EXT4_SB(sb)->s_qf_names[type],
4958 					EXT4_SB(sb)->s_jquota_fmt, type);
4959 }
4960 
4961 /*
4962  * Standard function to be called on quota_on
4963  */
4964 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
4965 			 struct path *path)
4966 {
4967 	int err;
4968 
4969 	if (!test_opt(sb, QUOTA))
4970 		return -EINVAL;
4971 
4972 	/* Quotafile not on the same filesystem? */
4973 	if (path->dentry->d_sb != sb)
4974 		return -EXDEV;
4975 	/* Journaling quota? */
4976 	if (EXT4_SB(sb)->s_qf_names[type]) {
4977 		/* Quotafile not in fs root? */
4978 		if (path->dentry->d_parent != sb->s_root)
4979 			ext4_msg(sb, KERN_WARNING,
4980 				"Quota file not on filesystem root. "
4981 				"Journaled quota will not work");
4982 	}
4983 
4984 	/*
4985 	 * When we journal data on quota file, we have to flush journal to see
4986 	 * all updates to the file when we bypass pagecache...
4987 	 */
4988 	if (EXT4_SB(sb)->s_journal &&
4989 	    ext4_should_journal_data(path->dentry->d_inode)) {
4990 		/*
4991 		 * We don't need to lock updates but journal_flush() could
4992 		 * otherwise be livelocked...
4993 		 */
4994 		jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
4995 		err = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
4996 		jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
4997 		if (err)
4998 			return err;
4999 	}
5000 
5001 	return dquot_quota_on(sb, type, format_id, path);
5002 }
5003 
5004 static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
5005 			     unsigned int flags)
5006 {
5007 	int err;
5008 	struct inode *qf_inode;
5009 	unsigned long qf_inums[MAXQUOTAS] = {
5010 		le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
5011 		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum)
5012 	};
5013 
5014 	BUG_ON(!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA));
5015 
5016 	if (!qf_inums[type])
5017 		return -EPERM;
5018 
5019 	qf_inode = ext4_iget(sb, qf_inums[type]);
5020 	if (IS_ERR(qf_inode)) {
5021 		ext4_error(sb, "Bad quota inode # %lu", qf_inums[type]);
5022 		return PTR_ERR(qf_inode);
5023 	}
5024 
5025 	/* Don't account quota for quota files to avoid recursion */
5026 	qf_inode->i_flags |= S_NOQUOTA;
5027 	err = dquot_enable(qf_inode, type, format_id, flags);
5028 	iput(qf_inode);
5029 
5030 	return err;
5031 }
5032 
5033 /* Enable usage tracking for all quota types. */
5034 static int ext4_enable_quotas(struct super_block *sb)
5035 {
5036 	int type, err = 0;
5037 	unsigned long qf_inums[MAXQUOTAS] = {
5038 		le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
5039 		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum)
5040 	};
5041 
5042 	sb_dqopt(sb)->flags |= DQUOT_QUOTA_SYS_FILE;
5043 	for (type = 0; type < MAXQUOTAS; type++) {
5044 		if (qf_inums[type]) {
5045 			err = ext4_quota_enable(sb, type, QFMT_VFS_V1,
5046 						DQUOT_USAGE_ENABLED);
5047 			if (err) {
5048 				ext4_warning(sb,
5049 					"Failed to enable quota tracking "
5050 					"(type=%d, err=%d). Please run "
5051 					"e2fsck to fix.", type, err);
5052 				return err;
5053 			}
5054 		}
5055 	}
5056 	return 0;
5057 }
5058 
5059 /*
5060  * quota_on function that is used when QUOTA feature is set.
5061  */
5062 static int ext4_quota_on_sysfile(struct super_block *sb, int type,
5063 				 int format_id)
5064 {
5065 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA))
5066 		return -EINVAL;
5067 
5068 	/*
5069 	 * USAGE was enabled at mount time. Only need to enable LIMITS now.
5070 	 */
5071 	return ext4_quota_enable(sb, type, format_id, DQUOT_LIMITS_ENABLED);
5072 }
5073 
5074 static int ext4_quota_off(struct super_block *sb, int type)
5075 {
5076 	struct inode *inode = sb_dqopt(sb)->files[type];
5077 	handle_t *handle;
5078 
5079 	/* Force all delayed allocation blocks to be allocated.
5080 	 * Caller already holds s_umount sem */
5081 	if (test_opt(sb, DELALLOC))
5082 		sync_filesystem(sb);
5083 
5084 	if (!inode)
5085 		goto out;
5086 
5087 	/* Update modification times of quota files when userspace can
5088 	 * start looking at them */
5089 	handle = ext4_journal_start(inode, EXT4_HT_QUOTA, 1);
5090 	if (IS_ERR(handle))
5091 		goto out;
5092 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
5093 	ext4_mark_inode_dirty(handle, inode);
5094 	ext4_journal_stop(handle);
5095 
5096 out:
5097 	return dquot_quota_off(sb, type);
5098 }
5099 
5100 /*
5101  * quota_off function that is used when QUOTA feature is set.
5102  */
5103 static int ext4_quota_off_sysfile(struct super_block *sb, int type)
5104 {
5105 	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA))
5106 		return -EINVAL;
5107 
5108 	/* Disable only the limits. */
5109 	return dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
5110 }
5111 
5112 /* Read data from quotafile - avoid pagecache and such because we cannot afford
5113  * acquiring the locks... As quota files are never truncated and quota code
5114  * itself serializes the operations (and no one else should touch the files)
5115  * we don't have to be afraid of races */
5116 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
5117 			       size_t len, loff_t off)
5118 {
5119 	struct inode *inode = sb_dqopt(sb)->files[type];
5120 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
5121 	int err = 0;
5122 	int offset = off & (sb->s_blocksize - 1);
5123 	int tocopy;
5124 	size_t toread;
5125 	struct buffer_head *bh;
5126 	loff_t i_size = i_size_read(inode);
5127 
5128 	if (off > i_size)
5129 		return 0;
5130 	if (off+len > i_size)
5131 		len = i_size-off;
5132 	toread = len;
5133 	while (toread > 0) {
5134 		tocopy = sb->s_blocksize - offset < toread ?
5135 				sb->s_blocksize - offset : toread;
5136 		bh = ext4_bread(NULL, inode, blk, 0, &err);
5137 		if (err)
5138 			return err;
5139 		if (!bh)	/* A hole? */
5140 			memset(data, 0, tocopy);
5141 		else
5142 			memcpy(data, bh->b_data+offset, tocopy);
5143 		brelse(bh);
5144 		offset = 0;
5145 		toread -= tocopy;
5146 		data += tocopy;
5147 		blk++;
5148 	}
5149 	return len;
5150 }
5151 
5152 /* Write to quotafile (we know the transaction is already started and has
5153  * enough credits) */
5154 static ssize_t ext4_quota_write(struct super_block *sb, int type,
5155 				const char *data, size_t len, loff_t off)
5156 {
5157 	struct inode *inode = sb_dqopt(sb)->files[type];
5158 	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
5159 	int err = 0;
5160 	int offset = off & (sb->s_blocksize - 1);
5161 	struct buffer_head *bh;
5162 	handle_t *handle = journal_current_handle();
5163 
5164 	if (EXT4_SB(sb)->s_journal && !handle) {
5165 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
5166 			" cancelled because transaction is not started",
5167 			(unsigned long long)off, (unsigned long long)len);
5168 		return -EIO;
5169 	}
5170 	/*
5171 	 * Since we account only one data block in transaction credits,
5172 	 * then it is impossible to cross a block boundary.
5173 	 */
5174 	if (sb->s_blocksize - offset < len) {
5175 		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
5176 			" cancelled because not block aligned",
5177 			(unsigned long long)off, (unsigned long long)len);
5178 		return -EIO;
5179 	}
5180 
5181 	bh = ext4_bread(handle, inode, blk, 1, &err);
5182 	if (!bh)
5183 		goto out;
5184 	err = ext4_journal_get_write_access(handle, bh);
5185 	if (err) {
5186 		brelse(bh);
5187 		goto out;
5188 	}
5189 	lock_buffer(bh);
5190 	memcpy(bh->b_data+offset, data, len);
5191 	flush_dcache_page(bh->b_page);
5192 	unlock_buffer(bh);
5193 	err = ext4_handle_dirty_metadata(handle, NULL, bh);
5194 	brelse(bh);
5195 out:
5196 	if (err)
5197 		return err;
5198 	if (inode->i_size < off + len) {
5199 		i_size_write(inode, off + len);
5200 		EXT4_I(inode)->i_disksize = inode->i_size;
5201 		ext4_mark_inode_dirty(handle, inode);
5202 	}
5203 	return len;
5204 }
5205 
5206 #endif
5207 
5208 static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
5209 		       const char *dev_name, void *data)
5210 {
5211 	return mount_bdev(fs_type, flags, dev_name, data, ext4_fill_super);
5212 }
5213 
5214 #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
5215 static inline void register_as_ext2(void)
5216 {
5217 	int err = register_filesystem(&ext2_fs_type);
5218 	if (err)
5219 		printk(KERN_WARNING
5220 		       "EXT4-fs: Unable to register as ext2 (%d)\n", err);
5221 }
5222 
5223 static inline void unregister_as_ext2(void)
5224 {
5225 	unregister_filesystem(&ext2_fs_type);
5226 }
5227 
5228 static inline int ext2_feature_set_ok(struct super_block *sb)
5229 {
5230 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP))
5231 		return 0;
5232 	if (sb->s_flags & MS_RDONLY)
5233 		return 1;
5234 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))
5235 		return 0;
5236 	return 1;
5237 }
5238 #else
5239 static inline void register_as_ext2(void) { }
5240 static inline void unregister_as_ext2(void) { }
5241 static inline int ext2_feature_set_ok(struct super_block *sb) { return 0; }
5242 #endif
5243 
5244 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
5245 static inline void register_as_ext3(void)
5246 {
5247 	int err = register_filesystem(&ext3_fs_type);
5248 	if (err)
5249 		printk(KERN_WARNING
5250 		       "EXT4-fs: Unable to register as ext3 (%d)\n", err);
5251 }
5252 
5253 static inline void unregister_as_ext3(void)
5254 {
5255 	unregister_filesystem(&ext3_fs_type);
5256 }
5257 
5258 static inline int ext3_feature_set_ok(struct super_block *sb)
5259 {
5260 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT3_FEATURE_INCOMPAT_SUPP))
5261 		return 0;
5262 	if (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL))
5263 		return 0;
5264 	if (sb->s_flags & MS_RDONLY)
5265 		return 1;
5266 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT3_FEATURE_RO_COMPAT_SUPP))
5267 		return 0;
5268 	return 1;
5269 }
5270 #else
5271 static inline void register_as_ext3(void) { }
5272 static inline void unregister_as_ext3(void) { }
5273 static inline int ext3_feature_set_ok(struct super_block *sb) { return 0; }
5274 #endif
5275 
5276 static struct file_system_type ext4_fs_type = {
5277 	.owner		= THIS_MODULE,
5278 	.name		= "ext4",
5279 	.mount		= ext4_mount,
5280 	.kill_sb	= kill_block_super,
5281 	.fs_flags	= FS_REQUIRES_DEV,
5282 };
5283 MODULE_ALIAS_FS("ext4");
5284 
5285 static int __init ext4_init_feat_adverts(void)
5286 {
5287 	struct ext4_features *ef;
5288 	int ret = -ENOMEM;
5289 
5290 	ef = kzalloc(sizeof(struct ext4_features), GFP_KERNEL);
5291 	if (!ef)
5292 		goto out;
5293 
5294 	ef->f_kobj.kset = ext4_kset;
5295 	init_completion(&ef->f_kobj_unregister);
5296 	ret = kobject_init_and_add(&ef->f_kobj, &ext4_feat_ktype, NULL,
5297 				   "features");
5298 	if (ret) {
5299 		kfree(ef);
5300 		goto out;
5301 	}
5302 
5303 	ext4_feat = ef;
5304 	ret = 0;
5305 out:
5306 	return ret;
5307 }
5308 
5309 static void ext4_exit_feat_adverts(void)
5310 {
5311 	kobject_put(&ext4_feat->f_kobj);
5312 	wait_for_completion(&ext4_feat->f_kobj_unregister);
5313 	kfree(ext4_feat);
5314 }
5315 
5316 /* Shared across all ext4 file systems */
5317 wait_queue_head_t ext4__ioend_wq[EXT4_WQ_HASH_SZ];
5318 struct mutex ext4__aio_mutex[EXT4_WQ_HASH_SZ];
5319 
5320 static int __init ext4_init_fs(void)
5321 {
5322 	int i, err;
5323 
5324 	ext4_li_info = NULL;
5325 	mutex_init(&ext4_li_mtx);
5326 
5327 	/* Build-time check for flags consistency */
5328 	ext4_check_flag_values();
5329 
5330 	for (i = 0; i < EXT4_WQ_HASH_SZ; i++) {
5331 		mutex_init(&ext4__aio_mutex[i]);
5332 		init_waitqueue_head(&ext4__ioend_wq[i]);
5333 	}
5334 
5335 	err = ext4_init_es();
5336 	if (err)
5337 		return err;
5338 
5339 	err = ext4_init_pageio();
5340 	if (err)
5341 		goto out7;
5342 
5343 	err = ext4_init_system_zone();
5344 	if (err)
5345 		goto out6;
5346 	ext4_kset = kset_create_and_add("ext4", NULL, fs_kobj);
5347 	if (!ext4_kset) {
5348 		err = -ENOMEM;
5349 		goto out5;
5350 	}
5351 	ext4_proc_root = proc_mkdir("fs/ext4", NULL);
5352 
5353 	err = ext4_init_feat_adverts();
5354 	if (err)
5355 		goto out4;
5356 
5357 	err = ext4_init_mballoc();
5358 	if (err)
5359 		goto out3;
5360 
5361 	err = ext4_init_xattr();
5362 	if (err)
5363 		goto out2;
5364 	err = init_inodecache();
5365 	if (err)
5366 		goto out1;
5367 	register_as_ext3();
5368 	register_as_ext2();
5369 	err = register_filesystem(&ext4_fs_type);
5370 	if (err)
5371 		goto out;
5372 
5373 	return 0;
5374 out:
5375 	unregister_as_ext2();
5376 	unregister_as_ext3();
5377 	destroy_inodecache();
5378 out1:
5379 	ext4_exit_xattr();
5380 out2:
5381 	ext4_exit_mballoc();
5382 out3:
5383 	ext4_exit_feat_adverts();
5384 out4:
5385 	if (ext4_proc_root)
5386 		remove_proc_entry("fs/ext4", NULL);
5387 	kset_unregister(ext4_kset);
5388 out5:
5389 	ext4_exit_system_zone();
5390 out6:
5391 	ext4_exit_pageio();
5392 out7:
5393 	ext4_exit_es();
5394 
5395 	return err;
5396 }
5397 
5398 static void __exit ext4_exit_fs(void)
5399 {
5400 	ext4_destroy_lazyinit_thread();
5401 	unregister_as_ext2();
5402 	unregister_as_ext3();
5403 	unregister_filesystem(&ext4_fs_type);
5404 	destroy_inodecache();
5405 	ext4_exit_xattr();
5406 	ext4_exit_mballoc();
5407 	ext4_exit_feat_adverts();
5408 	remove_proc_entry("fs/ext4", NULL);
5409 	kset_unregister(ext4_kset);
5410 	ext4_exit_system_zone();
5411 	ext4_exit_pageio();
5412 }
5413 
5414 MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
5415 MODULE_DESCRIPTION("Fourth Extended Filesystem");
5416 MODULE_LICENSE("GPL");
5417 module_init(ext4_init_fs)
5418 module_exit(ext4_exit_fs)
5419