xref: /openbmc/linux/fs/ext4/super.c (revision f98393a64ca1392130724c3acb4e3f325801d2b6)
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/jbd2.h>
24 #include <linux/ext4_fs.h>
25 #include <linux/ext4_jbd2.h>
26 #include <linux/slab.h>
27 #include <linux/init.h>
28 #include <linux/blkdev.h>
29 #include <linux/parser.h>
30 #include <linux/smp_lock.h>
31 #include <linux/buffer_head.h>
32 #include <linux/vfs.h>
33 #include <linux/random.h>
34 #include <linux/mount.h>
35 #include <linux/namei.h>
36 #include <linux/quotaops.h>
37 #include <linux/seq_file.h>
38 
39 #include <asm/uaccess.h>
40 
41 #include "xattr.h"
42 #include "acl.h"
43 #include "namei.h"
44 
45 static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
46 			     unsigned long journal_devnum);
47 static int ext4_create_journal(struct super_block *, struct ext4_super_block *,
48 			       unsigned int);
49 static void ext4_commit_super (struct super_block * sb,
50 			       struct ext4_super_block * es,
51 			       int sync);
52 static void ext4_mark_recovery_complete(struct super_block * sb,
53 					struct ext4_super_block * es);
54 static void ext4_clear_journal_err(struct super_block * sb,
55 				   struct ext4_super_block * es);
56 static int ext4_sync_fs(struct super_block *sb, int wait);
57 static const char *ext4_decode_error(struct super_block * sb, int errno,
58 				     char nbuf[16]);
59 static int ext4_remount (struct super_block * sb, int * flags, char * data);
60 static int ext4_statfs (struct dentry * dentry, struct kstatfs * buf);
61 static void ext4_unlockfs(struct super_block *sb);
62 static void ext4_write_super (struct super_block * sb);
63 static void ext4_write_super_lockfs(struct super_block *sb);
64 
65 
66 ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
67 			       struct ext4_group_desc *bg)
68 {
69 	return le32_to_cpu(bg->bg_block_bitmap) |
70 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
71 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_block_bitmap_hi) << 32 : 0);
72 }
73 
74 ext4_fsblk_t ext4_inode_bitmap(struct super_block *sb,
75 			       struct ext4_group_desc *bg)
76 {
77 	return le32_to_cpu(bg->bg_inode_bitmap) |
78 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
79 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_bitmap_hi) << 32 : 0);
80 }
81 
82 ext4_fsblk_t ext4_inode_table(struct super_block *sb,
83 			      struct ext4_group_desc *bg)
84 {
85 	return le32_to_cpu(bg->bg_inode_table) |
86 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
87 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_table_hi) << 32 : 0);
88 }
89 
90 void ext4_block_bitmap_set(struct super_block *sb,
91 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
92 {
93 	bg->bg_block_bitmap = cpu_to_le32((u32)blk);
94 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
95 		bg->bg_block_bitmap_hi = cpu_to_le32(blk >> 32);
96 }
97 
98 void ext4_inode_bitmap_set(struct super_block *sb,
99 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
100 {
101 	bg->bg_inode_bitmap  = cpu_to_le32((u32)blk);
102 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
103 		bg->bg_inode_bitmap_hi = cpu_to_le32(blk >> 32);
104 }
105 
106 void ext4_inode_table_set(struct super_block *sb,
107 			  struct ext4_group_desc *bg, ext4_fsblk_t blk)
108 {
109 	bg->bg_inode_table = cpu_to_le32((u32)blk);
110 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
111 		bg->bg_inode_table_hi = cpu_to_le32(blk >> 32);
112 }
113 
114 /*
115  * Wrappers for jbd2_journal_start/end.
116  *
117  * The only special thing we need to do here is to make sure that all
118  * journal_end calls result in the superblock being marked dirty, so
119  * that sync() will call the filesystem's write_super callback if
120  * appropriate.
121  */
122 handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
123 {
124 	journal_t *journal;
125 
126 	if (sb->s_flags & MS_RDONLY)
127 		return ERR_PTR(-EROFS);
128 
129 	/* Special case here: if the journal has aborted behind our
130 	 * backs (eg. EIO in the commit thread), then we still need to
131 	 * take the FS itself readonly cleanly. */
132 	journal = EXT4_SB(sb)->s_journal;
133 	if (is_journal_aborted(journal)) {
134 		ext4_abort(sb, __FUNCTION__,
135 			   "Detected aborted journal");
136 		return ERR_PTR(-EROFS);
137 	}
138 
139 	return jbd2_journal_start(journal, nblocks);
140 }
141 
142 /*
143  * The only special thing we need to do here is to make sure that all
144  * jbd2_journal_stop calls result in the superblock being marked dirty, so
145  * that sync() will call the filesystem's write_super callback if
146  * appropriate.
147  */
148 int __ext4_journal_stop(const char *where, handle_t *handle)
149 {
150 	struct super_block *sb;
151 	int err;
152 	int rc;
153 
154 	sb = handle->h_transaction->t_journal->j_private;
155 	err = handle->h_err;
156 	rc = jbd2_journal_stop(handle);
157 
158 	if (!err)
159 		err = rc;
160 	if (err)
161 		__ext4_std_error(sb, where, err);
162 	return err;
163 }
164 
165 void ext4_journal_abort_handle(const char *caller, const char *err_fn,
166 		struct buffer_head *bh, handle_t *handle, int err)
167 {
168 	char nbuf[16];
169 	const char *errstr = ext4_decode_error(NULL, err, nbuf);
170 
171 	if (bh)
172 		BUFFER_TRACE(bh, "abort");
173 
174 	if (!handle->h_err)
175 		handle->h_err = err;
176 
177 	if (is_handle_aborted(handle))
178 		return;
179 
180 	printk(KERN_ERR "%s: aborting transaction: %s in %s\n",
181 	       caller, errstr, err_fn);
182 
183 	jbd2_journal_abort_handle(handle);
184 }
185 
186 /* Deal with the reporting of failure conditions on a filesystem such as
187  * inconsistencies detected or read IO failures.
188  *
189  * On ext2, we can store the error state of the filesystem in the
190  * superblock.  That is not possible on ext4, because we may have other
191  * write ordering constraints on the superblock which prevent us from
192  * writing it out straight away; and given that the journal is about to
193  * be aborted, we can't rely on the current, or future, transactions to
194  * write out the superblock safely.
195  *
196  * We'll just use the jbd2_journal_abort() error code to record an error in
197  * the journal instead.  On recovery, the journal will compain about
198  * that error until we've noted it down and cleared it.
199  */
200 
201 static void ext4_handle_error(struct super_block *sb)
202 {
203 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
204 
205 	EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
206 	es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
207 
208 	if (sb->s_flags & MS_RDONLY)
209 		return;
210 
211 	if (!test_opt (sb, ERRORS_CONT)) {
212 		journal_t *journal = EXT4_SB(sb)->s_journal;
213 
214 		EXT4_SB(sb)->s_mount_opt |= EXT4_MOUNT_ABORT;
215 		if (journal)
216 			jbd2_journal_abort(journal, -EIO);
217 	}
218 	if (test_opt (sb, ERRORS_RO)) {
219 		printk (KERN_CRIT "Remounting filesystem read-only\n");
220 		sb->s_flags |= MS_RDONLY;
221 	}
222 	ext4_commit_super(sb, es, 1);
223 	if (test_opt(sb, ERRORS_PANIC))
224 		panic("EXT4-fs (device %s): panic forced after error\n",
225 			sb->s_id);
226 }
227 
228 void ext4_error (struct super_block * sb, const char * function,
229 		 const char * fmt, ...)
230 {
231 	va_list args;
232 
233 	va_start(args, fmt);
234 	printk(KERN_CRIT "EXT4-fs error (device %s): %s: ",sb->s_id, function);
235 	vprintk(fmt, args);
236 	printk("\n");
237 	va_end(args);
238 
239 	ext4_handle_error(sb);
240 }
241 
242 static const char *ext4_decode_error(struct super_block * sb, int errno,
243 				     char nbuf[16])
244 {
245 	char *errstr = NULL;
246 
247 	switch (errno) {
248 	case -EIO:
249 		errstr = "IO failure";
250 		break;
251 	case -ENOMEM:
252 		errstr = "Out of memory";
253 		break;
254 	case -EROFS:
255 		if (!sb || EXT4_SB(sb)->s_journal->j_flags & JBD2_ABORT)
256 			errstr = "Journal has aborted";
257 		else
258 			errstr = "Readonly filesystem";
259 		break;
260 	default:
261 		/* If the caller passed in an extra buffer for unknown
262 		 * errors, textualise them now.  Else we just return
263 		 * NULL. */
264 		if (nbuf) {
265 			/* Check for truncated error codes... */
266 			if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
267 				errstr = nbuf;
268 		}
269 		break;
270 	}
271 
272 	return errstr;
273 }
274 
275 /* __ext4_std_error decodes expected errors from journaling functions
276  * automatically and invokes the appropriate error response.  */
277 
278 void __ext4_std_error (struct super_block * sb, const char * function,
279 		       int errno)
280 {
281 	char nbuf[16];
282 	const char *errstr;
283 
284 	/* Special case: if the error is EROFS, and we're not already
285 	 * inside a transaction, then there's really no point in logging
286 	 * an error. */
287 	if (errno == -EROFS && journal_current_handle() == NULL &&
288 	    (sb->s_flags & MS_RDONLY))
289 		return;
290 
291 	errstr = ext4_decode_error(sb, errno, nbuf);
292 	printk (KERN_CRIT "EXT4-fs error (device %s) in %s: %s\n",
293 		sb->s_id, function, errstr);
294 
295 	ext4_handle_error(sb);
296 }
297 
298 /*
299  * ext4_abort is a much stronger failure handler than ext4_error.  The
300  * abort function may be used to deal with unrecoverable failures such
301  * as journal IO errors or ENOMEM at a critical moment in log management.
302  *
303  * We unconditionally force the filesystem into an ABORT|READONLY state,
304  * unless the error response on the fs has been set to panic in which
305  * case we take the easy way out and panic immediately.
306  */
307 
308 void ext4_abort (struct super_block * sb, const char * function,
309 		 const char * fmt, ...)
310 {
311 	va_list args;
312 
313 	printk (KERN_CRIT "ext4_abort called.\n");
314 
315 	va_start(args, fmt);
316 	printk(KERN_CRIT "EXT4-fs error (device %s): %s: ",sb->s_id, function);
317 	vprintk(fmt, args);
318 	printk("\n");
319 	va_end(args);
320 
321 	if (test_opt(sb, ERRORS_PANIC))
322 		panic("EXT4-fs panic from previous error\n");
323 
324 	if (sb->s_flags & MS_RDONLY)
325 		return;
326 
327 	printk(KERN_CRIT "Remounting filesystem read-only\n");
328 	EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
329 	sb->s_flags |= MS_RDONLY;
330 	EXT4_SB(sb)->s_mount_opt |= EXT4_MOUNT_ABORT;
331 	jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
332 }
333 
334 void ext4_warning (struct super_block * sb, const char * function,
335 		   const char * fmt, ...)
336 {
337 	va_list args;
338 
339 	va_start(args, fmt);
340 	printk(KERN_WARNING "EXT4-fs warning (device %s): %s: ",
341 	       sb->s_id, function);
342 	vprintk(fmt, args);
343 	printk("\n");
344 	va_end(args);
345 }
346 
347 void ext4_update_dynamic_rev(struct super_block *sb)
348 {
349 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
350 
351 	if (le32_to_cpu(es->s_rev_level) > EXT4_GOOD_OLD_REV)
352 		return;
353 
354 	ext4_warning(sb, __FUNCTION__,
355 		     "updating to rev %d because of new feature flag, "
356 		     "running e2fsck is recommended",
357 		     EXT4_DYNAMIC_REV);
358 
359 	es->s_first_ino = cpu_to_le32(EXT4_GOOD_OLD_FIRST_INO);
360 	es->s_inode_size = cpu_to_le16(EXT4_GOOD_OLD_INODE_SIZE);
361 	es->s_rev_level = cpu_to_le32(EXT4_DYNAMIC_REV);
362 	/* leave es->s_feature_*compat flags alone */
363 	/* es->s_uuid will be set by e2fsck if empty */
364 
365 	/*
366 	 * The rest of the superblock fields should be zero, and if not it
367 	 * means they are likely already in use, so leave them alone.  We
368 	 * can leave it up to e2fsck to clean up any inconsistencies there.
369 	 */
370 }
371 
372 /*
373  * Open the external journal device
374  */
375 static struct block_device *ext4_blkdev_get(dev_t dev)
376 {
377 	struct block_device *bdev;
378 	char b[BDEVNAME_SIZE];
379 
380 	bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
381 	if (IS_ERR(bdev))
382 		goto fail;
383 	return bdev;
384 
385 fail:
386 	printk(KERN_ERR "EXT4: failed to open journal device %s: %ld\n",
387 			__bdevname(dev, b), PTR_ERR(bdev));
388 	return NULL;
389 }
390 
391 /*
392  * Release the journal device
393  */
394 static int ext4_blkdev_put(struct block_device *bdev)
395 {
396 	bd_release(bdev);
397 	return blkdev_put(bdev);
398 }
399 
400 static int ext4_blkdev_remove(struct ext4_sb_info *sbi)
401 {
402 	struct block_device *bdev;
403 	int ret = -ENODEV;
404 
405 	bdev = sbi->journal_bdev;
406 	if (bdev) {
407 		ret = ext4_blkdev_put(bdev);
408 		sbi->journal_bdev = NULL;
409 	}
410 	return ret;
411 }
412 
413 static inline struct inode *orphan_list_entry(struct list_head *l)
414 {
415 	return &list_entry(l, struct ext4_inode_info, i_orphan)->vfs_inode;
416 }
417 
418 static void dump_orphan_list(struct super_block *sb, struct ext4_sb_info *sbi)
419 {
420 	struct list_head *l;
421 
422 	printk(KERN_ERR "sb orphan head is %d\n",
423 	       le32_to_cpu(sbi->s_es->s_last_orphan));
424 
425 	printk(KERN_ERR "sb_info orphan list:\n");
426 	list_for_each(l, &sbi->s_orphan) {
427 		struct inode *inode = orphan_list_entry(l);
428 		printk(KERN_ERR "  "
429 		       "inode %s:%lu at %p: mode %o, nlink %d, next %d\n",
430 		       inode->i_sb->s_id, inode->i_ino, inode,
431 		       inode->i_mode, inode->i_nlink,
432 		       NEXT_ORPHAN(inode));
433 	}
434 }
435 
436 static void ext4_put_super (struct super_block * sb)
437 {
438 	struct ext4_sb_info *sbi = EXT4_SB(sb);
439 	struct ext4_super_block *es = sbi->s_es;
440 	int i;
441 
442 	ext4_ext_release(sb);
443 	ext4_xattr_put_super(sb);
444 	jbd2_journal_destroy(sbi->s_journal);
445 	if (!(sb->s_flags & MS_RDONLY)) {
446 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
447 		es->s_state = cpu_to_le16(sbi->s_mount_state);
448 		BUFFER_TRACE(sbi->s_sbh, "marking dirty");
449 		mark_buffer_dirty(sbi->s_sbh);
450 		ext4_commit_super(sb, es, 1);
451 	}
452 
453 	for (i = 0; i < sbi->s_gdb_count; i++)
454 		brelse(sbi->s_group_desc[i]);
455 	kfree(sbi->s_group_desc);
456 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
457 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
458 	percpu_counter_destroy(&sbi->s_dirs_counter);
459 	brelse(sbi->s_sbh);
460 #ifdef CONFIG_QUOTA
461 	for (i = 0; i < MAXQUOTAS; i++)
462 		kfree(sbi->s_qf_names[i]);
463 #endif
464 
465 	/* Debugging code just in case the in-memory inode orphan list
466 	 * isn't empty.  The on-disk one can be non-empty if we've
467 	 * detected an error and taken the fs readonly, but the
468 	 * in-memory list had better be clean by this point. */
469 	if (!list_empty(&sbi->s_orphan))
470 		dump_orphan_list(sb, sbi);
471 	J_ASSERT(list_empty(&sbi->s_orphan));
472 
473 	invalidate_bdev(sb->s_bdev);
474 	if (sbi->journal_bdev && sbi->journal_bdev != sb->s_bdev) {
475 		/*
476 		 * Invalidate the journal device's buffers.  We don't want them
477 		 * floating about in memory - the physical journal device may
478 		 * hotswapped, and it breaks the `ro-after' testing code.
479 		 */
480 		sync_blockdev(sbi->journal_bdev);
481 		invalidate_bdev(sbi->journal_bdev);
482 		ext4_blkdev_remove(sbi);
483 	}
484 	sb->s_fs_info = NULL;
485 	kfree(sbi);
486 	return;
487 }
488 
489 static struct kmem_cache *ext4_inode_cachep;
490 
491 /*
492  * Called inside transaction, so use GFP_NOFS
493  */
494 static struct inode *ext4_alloc_inode(struct super_block *sb)
495 {
496 	struct ext4_inode_info *ei;
497 
498 	ei = kmem_cache_alloc(ext4_inode_cachep, GFP_NOFS);
499 	if (!ei)
500 		return NULL;
501 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
502 	ei->i_acl = EXT4_ACL_NOT_CACHED;
503 	ei->i_default_acl = EXT4_ACL_NOT_CACHED;
504 #endif
505 	ei->i_block_alloc_info = NULL;
506 	ei->vfs_inode.i_version = 1;
507 	memset(&ei->i_cached_extent, 0, sizeof(struct ext4_ext_cache));
508 	return &ei->vfs_inode;
509 }
510 
511 static void ext4_destroy_inode(struct inode *inode)
512 {
513 	kmem_cache_free(ext4_inode_cachep, EXT4_I(inode));
514 }
515 
516 static void init_once(void * foo, struct kmem_cache * cachep, unsigned long flags)
517 {
518 	struct ext4_inode_info *ei = (struct ext4_inode_info *) foo;
519 
520 	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
521 	    SLAB_CTOR_CONSTRUCTOR) {
522 		INIT_LIST_HEAD(&ei->i_orphan);
523 #ifdef CONFIG_EXT4DEV_FS_XATTR
524 		init_rwsem(&ei->xattr_sem);
525 #endif
526 		mutex_init(&ei->truncate_mutex);
527 		inode_init_once(&ei->vfs_inode);
528 	}
529 }
530 
531 static int init_inodecache(void)
532 {
533 	ext4_inode_cachep = kmem_cache_create("ext4_inode_cache",
534 					     sizeof(struct ext4_inode_info),
535 					     0, (SLAB_RECLAIM_ACCOUNT|
536 						SLAB_MEM_SPREAD),
537 					     init_once, NULL);
538 	if (ext4_inode_cachep == NULL)
539 		return -ENOMEM;
540 	return 0;
541 }
542 
543 static void destroy_inodecache(void)
544 {
545 	kmem_cache_destroy(ext4_inode_cachep);
546 }
547 
548 static void ext4_clear_inode(struct inode *inode)
549 {
550 	struct ext4_block_alloc_info *rsv = EXT4_I(inode)->i_block_alloc_info;
551 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
552 	if (EXT4_I(inode)->i_acl &&
553 			EXT4_I(inode)->i_acl != EXT4_ACL_NOT_CACHED) {
554 		posix_acl_release(EXT4_I(inode)->i_acl);
555 		EXT4_I(inode)->i_acl = EXT4_ACL_NOT_CACHED;
556 	}
557 	if (EXT4_I(inode)->i_default_acl &&
558 			EXT4_I(inode)->i_default_acl != EXT4_ACL_NOT_CACHED) {
559 		posix_acl_release(EXT4_I(inode)->i_default_acl);
560 		EXT4_I(inode)->i_default_acl = EXT4_ACL_NOT_CACHED;
561 	}
562 #endif
563 	ext4_discard_reservation(inode);
564 	EXT4_I(inode)->i_block_alloc_info = NULL;
565 	if (unlikely(rsv))
566 		kfree(rsv);
567 }
568 
569 static inline void ext4_show_quota_options(struct seq_file *seq, struct super_block *sb)
570 {
571 #if defined(CONFIG_QUOTA)
572 	struct ext4_sb_info *sbi = EXT4_SB(sb);
573 
574 	if (sbi->s_jquota_fmt)
575 		seq_printf(seq, ",jqfmt=%s",
576 		(sbi->s_jquota_fmt == QFMT_VFS_OLD) ? "vfsold": "vfsv0");
577 
578 	if (sbi->s_qf_names[USRQUOTA])
579 		seq_printf(seq, ",usrjquota=%s", sbi->s_qf_names[USRQUOTA]);
580 
581 	if (sbi->s_qf_names[GRPQUOTA])
582 		seq_printf(seq, ",grpjquota=%s", sbi->s_qf_names[GRPQUOTA]);
583 
584 	if (sbi->s_mount_opt & EXT4_MOUNT_USRQUOTA)
585 		seq_puts(seq, ",usrquota");
586 
587 	if (sbi->s_mount_opt & EXT4_MOUNT_GRPQUOTA)
588 		seq_puts(seq, ",grpquota");
589 #endif
590 }
591 
592 static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs)
593 {
594 	struct super_block *sb = vfs->mnt_sb;
595 
596 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
597 		seq_puts(seq, ",data=journal");
598 	else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
599 		seq_puts(seq, ",data=ordered");
600 	else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
601 		seq_puts(seq, ",data=writeback");
602 
603 	ext4_show_quota_options(seq, sb);
604 
605 	return 0;
606 }
607 
608 
609 static struct dentry *ext4_get_dentry(struct super_block *sb, void *vobjp)
610 {
611 	__u32 *objp = vobjp;
612 	unsigned long ino = objp[0];
613 	__u32 generation = objp[1];
614 	struct inode *inode;
615 	struct dentry *result;
616 
617 	if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
618 		return ERR_PTR(-ESTALE);
619 	if (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
620 		return ERR_PTR(-ESTALE);
621 
622 	/* iget isn't really right if the inode is currently unallocated!!
623 	 *
624 	 * ext4_read_inode will return a bad_inode if the inode had been
625 	 * deleted, so we should be safe.
626 	 *
627 	 * Currently we don't know the generation for parent directory, so
628 	 * a generation of 0 means "accept any"
629 	 */
630 	inode = iget(sb, ino);
631 	if (inode == NULL)
632 		return ERR_PTR(-ENOMEM);
633 	if (is_bad_inode(inode) ||
634 	    (generation && inode->i_generation != generation)) {
635 		iput(inode);
636 		return ERR_PTR(-ESTALE);
637 	}
638 	/* now to find a dentry.
639 	 * If possible, get a well-connected one
640 	 */
641 	result = d_alloc_anon(inode);
642 	if (!result) {
643 		iput(inode);
644 		return ERR_PTR(-ENOMEM);
645 	}
646 	return result;
647 }
648 
649 #ifdef CONFIG_QUOTA
650 #define QTYPE2NAME(t) ((t)==USRQUOTA?"user":"group")
651 #define QTYPE2MOPT(on, t) ((t)==USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
652 
653 static int ext4_dquot_initialize(struct inode *inode, int type);
654 static int ext4_dquot_drop(struct inode *inode);
655 static int ext4_write_dquot(struct dquot *dquot);
656 static int ext4_acquire_dquot(struct dquot *dquot);
657 static int ext4_release_dquot(struct dquot *dquot);
658 static int ext4_mark_dquot_dirty(struct dquot *dquot);
659 static int ext4_write_info(struct super_block *sb, int type);
660 static int ext4_quota_on(struct super_block *sb, int type, int format_id, char *path);
661 static int ext4_quota_on_mount(struct super_block *sb, int type);
662 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
663 			       size_t len, loff_t off);
664 static ssize_t ext4_quota_write(struct super_block *sb, int type,
665 				const char *data, size_t len, loff_t off);
666 
667 static struct dquot_operations ext4_quota_operations = {
668 	.initialize	= ext4_dquot_initialize,
669 	.drop		= ext4_dquot_drop,
670 	.alloc_space	= dquot_alloc_space,
671 	.alloc_inode	= dquot_alloc_inode,
672 	.free_space	= dquot_free_space,
673 	.free_inode	= dquot_free_inode,
674 	.transfer	= dquot_transfer,
675 	.write_dquot	= ext4_write_dquot,
676 	.acquire_dquot	= ext4_acquire_dquot,
677 	.release_dquot	= ext4_release_dquot,
678 	.mark_dirty	= ext4_mark_dquot_dirty,
679 	.write_info	= ext4_write_info
680 };
681 
682 static struct quotactl_ops ext4_qctl_operations = {
683 	.quota_on	= ext4_quota_on,
684 	.quota_off	= vfs_quota_off,
685 	.quota_sync	= vfs_quota_sync,
686 	.get_info	= vfs_get_dqinfo,
687 	.set_info	= vfs_set_dqinfo,
688 	.get_dqblk	= vfs_get_dqblk,
689 	.set_dqblk	= vfs_set_dqblk
690 };
691 #endif
692 
693 static const struct super_operations ext4_sops = {
694 	.alloc_inode	= ext4_alloc_inode,
695 	.destroy_inode	= ext4_destroy_inode,
696 	.read_inode	= ext4_read_inode,
697 	.write_inode	= ext4_write_inode,
698 	.dirty_inode	= ext4_dirty_inode,
699 	.delete_inode	= ext4_delete_inode,
700 	.put_super	= ext4_put_super,
701 	.write_super	= ext4_write_super,
702 	.sync_fs	= ext4_sync_fs,
703 	.write_super_lockfs = ext4_write_super_lockfs,
704 	.unlockfs	= ext4_unlockfs,
705 	.statfs		= ext4_statfs,
706 	.remount_fs	= ext4_remount,
707 	.clear_inode	= ext4_clear_inode,
708 	.show_options	= ext4_show_options,
709 #ifdef CONFIG_QUOTA
710 	.quota_read	= ext4_quota_read,
711 	.quota_write	= ext4_quota_write,
712 #endif
713 };
714 
715 static struct export_operations ext4_export_ops = {
716 	.get_parent = ext4_get_parent,
717 	.get_dentry = ext4_get_dentry,
718 };
719 
720 enum {
721 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
722 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
723 	Opt_nouid32, Opt_nocheck, Opt_debug, Opt_oldalloc, Opt_orlov,
724 	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
725 	Opt_reservation, Opt_noreservation, Opt_noload, Opt_nobh, Opt_bh,
726 	Opt_commit, Opt_journal_update, Opt_journal_inum, Opt_journal_dev,
727 	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
728 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
729 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_quota, Opt_noquota,
730 	Opt_ignore, Opt_barrier, Opt_err, Opt_resize, Opt_usrquota,
731 	Opt_grpquota, Opt_extents,
732 };
733 
734 static match_table_t tokens = {
735 	{Opt_bsd_df, "bsddf"},
736 	{Opt_minix_df, "minixdf"},
737 	{Opt_grpid, "grpid"},
738 	{Opt_grpid, "bsdgroups"},
739 	{Opt_nogrpid, "nogrpid"},
740 	{Opt_nogrpid, "sysvgroups"},
741 	{Opt_resgid, "resgid=%u"},
742 	{Opt_resuid, "resuid=%u"},
743 	{Opt_sb, "sb=%u"},
744 	{Opt_err_cont, "errors=continue"},
745 	{Opt_err_panic, "errors=panic"},
746 	{Opt_err_ro, "errors=remount-ro"},
747 	{Opt_nouid32, "nouid32"},
748 	{Opt_nocheck, "nocheck"},
749 	{Opt_nocheck, "check=none"},
750 	{Opt_debug, "debug"},
751 	{Opt_oldalloc, "oldalloc"},
752 	{Opt_orlov, "orlov"},
753 	{Opt_user_xattr, "user_xattr"},
754 	{Opt_nouser_xattr, "nouser_xattr"},
755 	{Opt_acl, "acl"},
756 	{Opt_noacl, "noacl"},
757 	{Opt_reservation, "reservation"},
758 	{Opt_noreservation, "noreservation"},
759 	{Opt_noload, "noload"},
760 	{Opt_nobh, "nobh"},
761 	{Opt_bh, "bh"},
762 	{Opt_commit, "commit=%u"},
763 	{Opt_journal_update, "journal=update"},
764 	{Opt_journal_inum, "journal=%u"},
765 	{Opt_journal_dev, "journal_dev=%u"},
766 	{Opt_abort, "abort"},
767 	{Opt_data_journal, "data=journal"},
768 	{Opt_data_ordered, "data=ordered"},
769 	{Opt_data_writeback, "data=writeback"},
770 	{Opt_offusrjquota, "usrjquota="},
771 	{Opt_usrjquota, "usrjquota=%s"},
772 	{Opt_offgrpjquota, "grpjquota="},
773 	{Opt_grpjquota, "grpjquota=%s"},
774 	{Opt_jqfmt_vfsold, "jqfmt=vfsold"},
775 	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
776 	{Opt_grpquota, "grpquota"},
777 	{Opt_noquota, "noquota"},
778 	{Opt_quota, "quota"},
779 	{Opt_usrquota, "usrquota"},
780 	{Opt_barrier, "barrier=%u"},
781 	{Opt_extents, "extents"},
782 	{Opt_err, NULL},
783 	{Opt_resize, "resize"},
784 };
785 
786 static ext4_fsblk_t get_sb_block(void **data)
787 {
788 	ext4_fsblk_t	sb_block;
789 	char		*options = (char *) *data;
790 
791 	if (!options || strncmp(options, "sb=", 3) != 0)
792 		return 1;	/* Default location */
793 	options += 3;
794 	/*todo: use simple_strtoll with >32bit ext4 */
795 	sb_block = simple_strtoul(options, &options, 0);
796 	if (*options && *options != ',') {
797 		printk("EXT4-fs: Invalid sb specification: %s\n",
798 		       (char *) *data);
799 		return 1;
800 	}
801 	if (*options == ',')
802 		options++;
803 	*data = (void *) options;
804 	return sb_block;
805 }
806 
807 static int parse_options (char *options, struct super_block *sb,
808 			  unsigned int *inum, unsigned long *journal_devnum,
809 			  ext4_fsblk_t *n_blocks_count, int is_remount)
810 {
811 	struct ext4_sb_info *sbi = EXT4_SB(sb);
812 	char * p;
813 	substring_t args[MAX_OPT_ARGS];
814 	int data_opt = 0;
815 	int option;
816 #ifdef CONFIG_QUOTA
817 	int qtype;
818 	char *qname;
819 #endif
820 
821 	if (!options)
822 		return 1;
823 
824 	while ((p = strsep (&options, ",")) != NULL) {
825 		int token;
826 		if (!*p)
827 			continue;
828 
829 		token = match_token(p, tokens, args);
830 		switch (token) {
831 		case Opt_bsd_df:
832 			clear_opt (sbi->s_mount_opt, MINIX_DF);
833 			break;
834 		case Opt_minix_df:
835 			set_opt (sbi->s_mount_opt, MINIX_DF);
836 			break;
837 		case Opt_grpid:
838 			set_opt (sbi->s_mount_opt, GRPID);
839 			break;
840 		case Opt_nogrpid:
841 			clear_opt (sbi->s_mount_opt, GRPID);
842 			break;
843 		case Opt_resuid:
844 			if (match_int(&args[0], &option))
845 				return 0;
846 			sbi->s_resuid = option;
847 			break;
848 		case Opt_resgid:
849 			if (match_int(&args[0], &option))
850 				return 0;
851 			sbi->s_resgid = option;
852 			break;
853 		case Opt_sb:
854 			/* handled by get_sb_block() instead of here */
855 			/* *sb_block = match_int(&args[0]); */
856 			break;
857 		case Opt_err_panic:
858 			clear_opt (sbi->s_mount_opt, ERRORS_CONT);
859 			clear_opt (sbi->s_mount_opt, ERRORS_RO);
860 			set_opt (sbi->s_mount_opt, ERRORS_PANIC);
861 			break;
862 		case Opt_err_ro:
863 			clear_opt (sbi->s_mount_opt, ERRORS_CONT);
864 			clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
865 			set_opt (sbi->s_mount_opt, ERRORS_RO);
866 			break;
867 		case Opt_err_cont:
868 			clear_opt (sbi->s_mount_opt, ERRORS_RO);
869 			clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
870 			set_opt (sbi->s_mount_opt, ERRORS_CONT);
871 			break;
872 		case Opt_nouid32:
873 			set_opt (sbi->s_mount_opt, NO_UID32);
874 			break;
875 		case Opt_nocheck:
876 			clear_opt (sbi->s_mount_opt, CHECK);
877 			break;
878 		case Opt_debug:
879 			set_opt (sbi->s_mount_opt, DEBUG);
880 			break;
881 		case Opt_oldalloc:
882 			set_opt (sbi->s_mount_opt, OLDALLOC);
883 			break;
884 		case Opt_orlov:
885 			clear_opt (sbi->s_mount_opt, OLDALLOC);
886 			break;
887 #ifdef CONFIG_EXT4DEV_FS_XATTR
888 		case Opt_user_xattr:
889 			set_opt (sbi->s_mount_opt, XATTR_USER);
890 			break;
891 		case Opt_nouser_xattr:
892 			clear_opt (sbi->s_mount_opt, XATTR_USER);
893 			break;
894 #else
895 		case Opt_user_xattr:
896 		case Opt_nouser_xattr:
897 			printk("EXT4 (no)user_xattr options not supported\n");
898 			break;
899 #endif
900 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
901 		case Opt_acl:
902 			set_opt(sbi->s_mount_opt, POSIX_ACL);
903 			break;
904 		case Opt_noacl:
905 			clear_opt(sbi->s_mount_opt, POSIX_ACL);
906 			break;
907 #else
908 		case Opt_acl:
909 		case Opt_noacl:
910 			printk("EXT4 (no)acl options not supported\n");
911 			break;
912 #endif
913 		case Opt_reservation:
914 			set_opt(sbi->s_mount_opt, RESERVATION);
915 			break;
916 		case Opt_noreservation:
917 			clear_opt(sbi->s_mount_opt, RESERVATION);
918 			break;
919 		case Opt_journal_update:
920 			/* @@@ FIXME */
921 			/* Eventually we will want to be able to create
922 			   a journal file here.  For now, only allow the
923 			   user to specify an existing inode to be the
924 			   journal file. */
925 			if (is_remount) {
926 				printk(KERN_ERR "EXT4-fs: cannot specify "
927 				       "journal on remount\n");
928 				return 0;
929 			}
930 			set_opt (sbi->s_mount_opt, UPDATE_JOURNAL);
931 			break;
932 		case Opt_journal_inum:
933 			if (is_remount) {
934 				printk(KERN_ERR "EXT4-fs: cannot specify "
935 				       "journal on remount\n");
936 				return 0;
937 			}
938 			if (match_int(&args[0], &option))
939 				return 0;
940 			*inum = option;
941 			break;
942 		case Opt_journal_dev:
943 			if (is_remount) {
944 				printk(KERN_ERR "EXT4-fs: cannot specify "
945 				       "journal on remount\n");
946 				return 0;
947 			}
948 			if (match_int(&args[0], &option))
949 				return 0;
950 			*journal_devnum = option;
951 			break;
952 		case Opt_noload:
953 			set_opt (sbi->s_mount_opt, NOLOAD);
954 			break;
955 		case Opt_commit:
956 			if (match_int(&args[0], &option))
957 				return 0;
958 			if (option < 0)
959 				return 0;
960 			if (option == 0)
961 				option = JBD_DEFAULT_MAX_COMMIT_AGE;
962 			sbi->s_commit_interval = HZ * option;
963 			break;
964 		case Opt_data_journal:
965 			data_opt = EXT4_MOUNT_JOURNAL_DATA;
966 			goto datacheck;
967 		case Opt_data_ordered:
968 			data_opt = EXT4_MOUNT_ORDERED_DATA;
969 			goto datacheck;
970 		case Opt_data_writeback:
971 			data_opt = EXT4_MOUNT_WRITEBACK_DATA;
972 		datacheck:
973 			if (is_remount) {
974 				if ((sbi->s_mount_opt & EXT4_MOUNT_DATA_FLAGS)
975 						!= data_opt) {
976 					printk(KERN_ERR
977 						"EXT4-fs: cannot change data "
978 						"mode on remount\n");
979 					return 0;
980 				}
981 			} else {
982 				sbi->s_mount_opt &= ~EXT4_MOUNT_DATA_FLAGS;
983 				sbi->s_mount_opt |= data_opt;
984 			}
985 			break;
986 #ifdef CONFIG_QUOTA
987 		case Opt_usrjquota:
988 			qtype = USRQUOTA;
989 			goto set_qf_name;
990 		case Opt_grpjquota:
991 			qtype = GRPQUOTA;
992 set_qf_name:
993 			if (sb_any_quota_enabled(sb)) {
994 				printk(KERN_ERR
995 					"EXT4-fs: Cannot change journalled "
996 					"quota options when quota turned on.\n");
997 				return 0;
998 			}
999 			qname = match_strdup(&args[0]);
1000 			if (!qname) {
1001 				printk(KERN_ERR
1002 					"EXT4-fs: not enough memory for "
1003 					"storing quotafile name.\n");
1004 				return 0;
1005 			}
1006 			if (sbi->s_qf_names[qtype] &&
1007 			    strcmp(sbi->s_qf_names[qtype], qname)) {
1008 				printk(KERN_ERR
1009 					"EXT4-fs: %s quota file already "
1010 					"specified.\n", QTYPE2NAME(qtype));
1011 				kfree(qname);
1012 				return 0;
1013 			}
1014 			sbi->s_qf_names[qtype] = qname;
1015 			if (strchr(sbi->s_qf_names[qtype], '/')) {
1016 				printk(KERN_ERR
1017 					"EXT4-fs: quotafile must be on "
1018 					"filesystem root.\n");
1019 				kfree(sbi->s_qf_names[qtype]);
1020 				sbi->s_qf_names[qtype] = NULL;
1021 				return 0;
1022 			}
1023 			set_opt(sbi->s_mount_opt, QUOTA);
1024 			break;
1025 		case Opt_offusrjquota:
1026 			qtype = USRQUOTA;
1027 			goto clear_qf_name;
1028 		case Opt_offgrpjquota:
1029 			qtype = GRPQUOTA;
1030 clear_qf_name:
1031 			if (sb_any_quota_enabled(sb)) {
1032 				printk(KERN_ERR "EXT4-fs: Cannot change "
1033 					"journalled quota options when "
1034 					"quota turned on.\n");
1035 				return 0;
1036 			}
1037 			/*
1038 			 * The space will be released later when all options
1039 			 * are confirmed to be correct
1040 			 */
1041 			sbi->s_qf_names[qtype] = NULL;
1042 			break;
1043 		case Opt_jqfmt_vfsold:
1044 			sbi->s_jquota_fmt = QFMT_VFS_OLD;
1045 			break;
1046 		case Opt_jqfmt_vfsv0:
1047 			sbi->s_jquota_fmt = QFMT_VFS_V0;
1048 			break;
1049 		case Opt_quota:
1050 		case Opt_usrquota:
1051 			set_opt(sbi->s_mount_opt, QUOTA);
1052 			set_opt(sbi->s_mount_opt, USRQUOTA);
1053 			break;
1054 		case Opt_grpquota:
1055 			set_opt(sbi->s_mount_opt, QUOTA);
1056 			set_opt(sbi->s_mount_opt, GRPQUOTA);
1057 			break;
1058 		case Opt_noquota:
1059 			if (sb_any_quota_enabled(sb)) {
1060 				printk(KERN_ERR "EXT4-fs: Cannot change quota "
1061 					"options when quota turned on.\n");
1062 				return 0;
1063 			}
1064 			clear_opt(sbi->s_mount_opt, QUOTA);
1065 			clear_opt(sbi->s_mount_opt, USRQUOTA);
1066 			clear_opt(sbi->s_mount_opt, GRPQUOTA);
1067 			break;
1068 #else
1069 		case Opt_quota:
1070 		case Opt_usrquota:
1071 		case Opt_grpquota:
1072 		case Opt_usrjquota:
1073 		case Opt_grpjquota:
1074 		case Opt_offusrjquota:
1075 		case Opt_offgrpjquota:
1076 		case Opt_jqfmt_vfsold:
1077 		case Opt_jqfmt_vfsv0:
1078 			printk(KERN_ERR
1079 				"EXT4-fs: journalled quota options not "
1080 				"supported.\n");
1081 			break;
1082 		case Opt_noquota:
1083 			break;
1084 #endif
1085 		case Opt_abort:
1086 			set_opt(sbi->s_mount_opt, ABORT);
1087 			break;
1088 		case Opt_barrier:
1089 			if (match_int(&args[0], &option))
1090 				return 0;
1091 			if (option)
1092 				set_opt(sbi->s_mount_opt, BARRIER);
1093 			else
1094 				clear_opt(sbi->s_mount_opt, BARRIER);
1095 			break;
1096 		case Opt_ignore:
1097 			break;
1098 		case Opt_resize:
1099 			if (!is_remount) {
1100 				printk("EXT4-fs: resize option only available "
1101 					"for remount\n");
1102 				return 0;
1103 			}
1104 			if (match_int(&args[0], &option) != 0)
1105 				return 0;
1106 			*n_blocks_count = option;
1107 			break;
1108 		case Opt_nobh:
1109 			set_opt(sbi->s_mount_opt, NOBH);
1110 			break;
1111 		case Opt_bh:
1112 			clear_opt(sbi->s_mount_opt, NOBH);
1113 			break;
1114 		case Opt_extents:
1115 			set_opt (sbi->s_mount_opt, EXTENTS);
1116 			break;
1117 		default:
1118 			printk (KERN_ERR
1119 				"EXT4-fs: Unrecognized mount option \"%s\" "
1120 				"or missing value\n", p);
1121 			return 0;
1122 		}
1123 	}
1124 #ifdef CONFIG_QUOTA
1125 	if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
1126 		if ((sbi->s_mount_opt & EXT4_MOUNT_USRQUOTA) &&
1127 		     sbi->s_qf_names[USRQUOTA])
1128 			clear_opt(sbi->s_mount_opt, USRQUOTA);
1129 
1130 		if ((sbi->s_mount_opt & EXT4_MOUNT_GRPQUOTA) &&
1131 		     sbi->s_qf_names[GRPQUOTA])
1132 			clear_opt(sbi->s_mount_opt, GRPQUOTA);
1133 
1134 		if ((sbi->s_qf_names[USRQUOTA] &&
1135 				(sbi->s_mount_opt & EXT4_MOUNT_GRPQUOTA)) ||
1136 		    (sbi->s_qf_names[GRPQUOTA] &&
1137 				(sbi->s_mount_opt & EXT4_MOUNT_USRQUOTA))) {
1138 			printk(KERN_ERR "EXT4-fs: old and new quota "
1139 					"format mixing.\n");
1140 			return 0;
1141 		}
1142 
1143 		if (!sbi->s_jquota_fmt) {
1144 			printk(KERN_ERR "EXT4-fs: journalled quota format "
1145 					"not specified.\n");
1146 			return 0;
1147 		}
1148 	} else {
1149 		if (sbi->s_jquota_fmt) {
1150 			printk(KERN_ERR "EXT4-fs: journalled quota format "
1151 					"specified with no journalling "
1152 					"enabled.\n");
1153 			return 0;
1154 		}
1155 	}
1156 #endif
1157 	return 1;
1158 }
1159 
1160 static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
1161 			    int read_only)
1162 {
1163 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1164 	int res = 0;
1165 
1166 	if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
1167 		printk (KERN_ERR "EXT4-fs warning: revision level too high, "
1168 			"forcing read-only mode\n");
1169 		res = MS_RDONLY;
1170 	}
1171 	if (read_only)
1172 		return res;
1173 	if (!(sbi->s_mount_state & EXT4_VALID_FS))
1174 		printk (KERN_WARNING "EXT4-fs warning: mounting unchecked fs, "
1175 			"running e2fsck is recommended\n");
1176 	else if ((sbi->s_mount_state & EXT4_ERROR_FS))
1177 		printk (KERN_WARNING
1178 			"EXT4-fs warning: mounting fs with errors, "
1179 			"running e2fsck is recommended\n");
1180 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
1181 		 le16_to_cpu(es->s_mnt_count) >=
1182 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
1183 		printk (KERN_WARNING
1184 			"EXT4-fs warning: maximal mount count reached, "
1185 			"running e2fsck is recommended\n");
1186 	else if (le32_to_cpu(es->s_checkinterval) &&
1187 		(le32_to_cpu(es->s_lastcheck) +
1188 			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
1189 		printk (KERN_WARNING
1190 			"EXT4-fs warning: checktime reached, "
1191 			"running e2fsck is recommended\n");
1192 #if 0
1193 		/* @@@ We _will_ want to clear the valid bit if we find
1194 		 * inconsistencies, to force a fsck at reboot.  But for
1195 		 * a plain journaled filesystem we can keep it set as
1196 		 * valid forever! :)
1197 		 */
1198 	es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) & ~EXT4_VALID_FS);
1199 #endif
1200 	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
1201 		es->s_max_mnt_count = cpu_to_le16(EXT4_DFL_MAX_MNT_COUNT);
1202 	es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
1203 	es->s_mtime = cpu_to_le32(get_seconds());
1204 	ext4_update_dynamic_rev(sb);
1205 	EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
1206 
1207 	ext4_commit_super(sb, es, 1);
1208 	if (test_opt(sb, DEBUG))
1209 		printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%lu, "
1210 				"bpg=%lu, ipg=%lu, mo=%04lx]\n",
1211 			sb->s_blocksize,
1212 			sbi->s_groups_count,
1213 			EXT4_BLOCKS_PER_GROUP(sb),
1214 			EXT4_INODES_PER_GROUP(sb),
1215 			sbi->s_mount_opt);
1216 
1217 	printk(KERN_INFO "EXT4 FS on %s, ", sb->s_id);
1218 	if (EXT4_SB(sb)->s_journal->j_inode == NULL) {
1219 		char b[BDEVNAME_SIZE];
1220 
1221 		printk("external journal on %s\n",
1222 			bdevname(EXT4_SB(sb)->s_journal->j_dev, b));
1223 	} else {
1224 		printk("internal journal\n");
1225 	}
1226 	return res;
1227 }
1228 
1229 /* Called at mount-time, super-block is locked */
1230 static int ext4_check_descriptors (struct super_block * sb)
1231 {
1232 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1233 	ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
1234 	ext4_fsblk_t last_block;
1235 	ext4_fsblk_t block_bitmap;
1236 	ext4_fsblk_t inode_bitmap;
1237 	ext4_fsblk_t inode_table;
1238 	struct ext4_group_desc * gdp = NULL;
1239 	int desc_block = 0;
1240 	int i;
1241 
1242 	ext4_debug ("Checking group descriptors");
1243 
1244 	for (i = 0; i < sbi->s_groups_count; i++)
1245 	{
1246 		if (i == sbi->s_groups_count - 1)
1247 			last_block = ext4_blocks_count(sbi->s_es) - 1;
1248 		else
1249 			last_block = first_block +
1250 				(EXT4_BLOCKS_PER_GROUP(sb) - 1);
1251 
1252 		if ((i % EXT4_DESC_PER_BLOCK(sb)) == 0)
1253 			gdp = (struct ext4_group_desc *)
1254 					sbi->s_group_desc[desc_block++]->b_data;
1255 		block_bitmap = ext4_block_bitmap(sb, gdp);
1256 		if (block_bitmap < first_block || block_bitmap > last_block)
1257 		{
1258 			ext4_error (sb, "ext4_check_descriptors",
1259 				    "Block bitmap for group %d"
1260 				    " not in group (block %llu)!",
1261 				    i, block_bitmap);
1262 			return 0;
1263 		}
1264 		inode_bitmap = ext4_inode_bitmap(sb, gdp);
1265 		if (inode_bitmap < first_block || inode_bitmap > last_block)
1266 		{
1267 			ext4_error (sb, "ext4_check_descriptors",
1268 				    "Inode bitmap for group %d"
1269 				    " not in group (block %llu)!",
1270 				    i, inode_bitmap);
1271 			return 0;
1272 		}
1273 		inode_table = ext4_inode_table(sb, gdp);
1274 		if (inode_table < first_block ||
1275 		    inode_table + sbi->s_itb_per_group > last_block)
1276 		{
1277 			ext4_error (sb, "ext4_check_descriptors",
1278 				    "Inode table for group %d"
1279 				    " not in group (block %llu)!",
1280 				    i, inode_table);
1281 			return 0;
1282 		}
1283 		first_block += EXT4_BLOCKS_PER_GROUP(sb);
1284 		gdp = (struct ext4_group_desc *)
1285 			((__u8 *)gdp + EXT4_DESC_SIZE(sb));
1286 	}
1287 
1288 	ext4_free_blocks_count_set(sbi->s_es, ext4_count_free_blocks(sb));
1289 	sbi->s_es->s_free_inodes_count=cpu_to_le32(ext4_count_free_inodes(sb));
1290 	return 1;
1291 }
1292 
1293 
1294 /* ext4_orphan_cleanup() walks a singly-linked list of inodes (starting at
1295  * the superblock) which were deleted from all directories, but held open by
1296  * a process at the time of a crash.  We walk the list and try to delete these
1297  * inodes at recovery time (only with a read-write filesystem).
1298  *
1299  * In order to keep the orphan inode chain consistent during traversal (in
1300  * case of crash during recovery), we link each inode into the superblock
1301  * orphan list_head and handle it the same way as an inode deletion during
1302  * normal operation (which journals the operations for us).
1303  *
1304  * We only do an iget() and an iput() on each inode, which is very safe if we
1305  * accidentally point at an in-use or already deleted inode.  The worst that
1306  * can happen in this case is that we get a "bit already cleared" message from
1307  * ext4_free_inode().  The only reason we would point at a wrong inode is if
1308  * e2fsck was run on this filesystem, and it must have already done the orphan
1309  * inode cleanup for us, so we can safely abort without any further action.
1310  */
1311 static void ext4_orphan_cleanup (struct super_block * sb,
1312 				 struct ext4_super_block * es)
1313 {
1314 	unsigned int s_flags = sb->s_flags;
1315 	int nr_orphans = 0, nr_truncates = 0;
1316 #ifdef CONFIG_QUOTA
1317 	int i;
1318 #endif
1319 	if (!es->s_last_orphan) {
1320 		jbd_debug(4, "no orphan inodes to clean up\n");
1321 		return;
1322 	}
1323 
1324 	if (bdev_read_only(sb->s_bdev)) {
1325 		printk(KERN_ERR "EXT4-fs: write access "
1326 			"unavailable, skipping orphan cleanup.\n");
1327 		return;
1328 	}
1329 
1330 	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
1331 		if (es->s_last_orphan)
1332 			jbd_debug(1, "Errors on filesystem, "
1333 				  "clearing orphan list.\n");
1334 		es->s_last_orphan = 0;
1335 		jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
1336 		return;
1337 	}
1338 
1339 	if (s_flags & MS_RDONLY) {
1340 		printk(KERN_INFO "EXT4-fs: %s: orphan cleanup on readonly fs\n",
1341 		       sb->s_id);
1342 		sb->s_flags &= ~MS_RDONLY;
1343 	}
1344 #ifdef CONFIG_QUOTA
1345 	/* Needed for iput() to work correctly and not trash data */
1346 	sb->s_flags |= MS_ACTIVE;
1347 	/* Turn on quotas so that they are updated correctly */
1348 	for (i = 0; i < MAXQUOTAS; i++) {
1349 		if (EXT4_SB(sb)->s_qf_names[i]) {
1350 			int ret = ext4_quota_on_mount(sb, i);
1351 			if (ret < 0)
1352 				printk(KERN_ERR
1353 					"EXT4-fs: Cannot turn on journalled "
1354 					"quota: error %d\n", ret);
1355 		}
1356 	}
1357 #endif
1358 
1359 	while (es->s_last_orphan) {
1360 		struct inode *inode;
1361 
1362 		if (!(inode =
1363 		      ext4_orphan_get(sb, le32_to_cpu(es->s_last_orphan)))) {
1364 			es->s_last_orphan = 0;
1365 			break;
1366 		}
1367 
1368 		list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
1369 		DQUOT_INIT(inode);
1370 		if (inode->i_nlink) {
1371 			printk(KERN_DEBUG
1372 				"%s: truncating inode %lu to %Ld bytes\n",
1373 				__FUNCTION__, inode->i_ino, inode->i_size);
1374 			jbd_debug(2, "truncating inode %lu to %Ld bytes\n",
1375 				  inode->i_ino, inode->i_size);
1376 			ext4_truncate(inode);
1377 			nr_truncates++;
1378 		} else {
1379 			printk(KERN_DEBUG
1380 				"%s: deleting unreferenced inode %lu\n",
1381 				__FUNCTION__, inode->i_ino);
1382 			jbd_debug(2, "deleting unreferenced inode %lu\n",
1383 				  inode->i_ino);
1384 			nr_orphans++;
1385 		}
1386 		iput(inode);  /* The delete magic happens here! */
1387 	}
1388 
1389 #define PLURAL(x) (x), ((x)==1) ? "" : "s"
1390 
1391 	if (nr_orphans)
1392 		printk(KERN_INFO "EXT4-fs: %s: %d orphan inode%s deleted\n",
1393 		       sb->s_id, PLURAL(nr_orphans));
1394 	if (nr_truncates)
1395 		printk(KERN_INFO "EXT4-fs: %s: %d truncate%s cleaned up\n",
1396 		       sb->s_id, PLURAL(nr_truncates));
1397 #ifdef CONFIG_QUOTA
1398 	/* Turn quotas off */
1399 	for (i = 0; i < MAXQUOTAS; i++) {
1400 		if (sb_dqopt(sb)->files[i])
1401 			vfs_quota_off(sb, i);
1402 	}
1403 #endif
1404 	sb->s_flags = s_flags; /* Restore MS_RDONLY status */
1405 }
1406 
1407 #define log2(n) ffz(~(n))
1408 
1409 /*
1410  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
1411  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
1412  * We need to be 1 filesystem block less than the 2^32 sector limit.
1413  */
1414 static loff_t ext4_max_size(int bits)
1415 {
1416 	loff_t res = EXT4_NDIR_BLOCKS;
1417 	/* This constant is calculated to be the largest file size for a
1418 	 * dense, 4k-blocksize file such that the total number of
1419 	 * sectors in the file, including data and all indirect blocks,
1420 	 * does not exceed 2^32. */
1421 	const loff_t upper_limit = 0x1ff7fffd000LL;
1422 
1423 	res += 1LL << (bits-2);
1424 	res += 1LL << (2*(bits-2));
1425 	res += 1LL << (3*(bits-2));
1426 	res <<= bits;
1427 	if (res > upper_limit)
1428 		res = upper_limit;
1429 	return res;
1430 }
1431 
1432 static ext4_fsblk_t descriptor_loc(struct super_block *sb,
1433 				ext4_fsblk_t logical_sb_block, int nr)
1434 {
1435 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1436 	unsigned long bg, first_meta_bg;
1437 	int has_super = 0;
1438 
1439 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
1440 
1441 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
1442 	    nr < first_meta_bg)
1443 		return logical_sb_block + nr + 1;
1444 	bg = sbi->s_desc_per_block * nr;
1445 	if (ext4_bg_has_super(sb, bg))
1446 		has_super = 1;
1447 	return (has_super + ext4_group_first_block_no(sb, bg));
1448 }
1449 
1450 
1451 static int ext4_fill_super (struct super_block *sb, void *data, int silent)
1452 {
1453 	struct buffer_head * bh;
1454 	struct ext4_super_block *es = NULL;
1455 	struct ext4_sb_info *sbi;
1456 	ext4_fsblk_t block;
1457 	ext4_fsblk_t sb_block = get_sb_block(&data);
1458 	ext4_fsblk_t logical_sb_block;
1459 	unsigned long offset = 0;
1460 	unsigned int journal_inum = 0;
1461 	unsigned long journal_devnum = 0;
1462 	unsigned long def_mount_opts;
1463 	struct inode *root;
1464 	int blocksize;
1465 	int hblock;
1466 	int db_count;
1467 	int i;
1468 	int needs_recovery;
1469 	__le32 features;
1470 	__u64 blocks_count;
1471 
1472 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
1473 	if (!sbi)
1474 		return -ENOMEM;
1475 	sb->s_fs_info = sbi;
1476 	sbi->s_mount_opt = 0;
1477 	sbi->s_resuid = EXT4_DEF_RESUID;
1478 	sbi->s_resgid = EXT4_DEF_RESGID;
1479 
1480 	unlock_kernel();
1481 
1482 	blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
1483 	if (!blocksize) {
1484 		printk(KERN_ERR "EXT4-fs: unable to set blocksize\n");
1485 		goto out_fail;
1486 	}
1487 
1488 	/*
1489 	 * The ext4 superblock will not be buffer aligned for other than 1kB
1490 	 * block sizes.  We need to calculate the offset from buffer start.
1491 	 */
1492 	if (blocksize != EXT4_MIN_BLOCK_SIZE) {
1493 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
1494 		offset = do_div(logical_sb_block, blocksize);
1495 	} else {
1496 		logical_sb_block = sb_block;
1497 	}
1498 
1499 	if (!(bh = sb_bread(sb, logical_sb_block))) {
1500 		printk (KERN_ERR "EXT4-fs: unable to read superblock\n");
1501 		goto out_fail;
1502 	}
1503 	/*
1504 	 * Note: s_es must be initialized as soon as possible because
1505 	 *       some ext4 macro-instructions depend on its value
1506 	 */
1507 	es = (struct ext4_super_block *) (((char *)bh->b_data) + offset);
1508 	sbi->s_es = es;
1509 	sb->s_magic = le16_to_cpu(es->s_magic);
1510 	if (sb->s_magic != EXT4_SUPER_MAGIC)
1511 		goto cantfind_ext4;
1512 
1513 	/* Set defaults before we parse the mount options */
1514 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
1515 	if (def_mount_opts & EXT4_DEFM_DEBUG)
1516 		set_opt(sbi->s_mount_opt, DEBUG);
1517 	if (def_mount_opts & EXT4_DEFM_BSDGROUPS)
1518 		set_opt(sbi->s_mount_opt, GRPID);
1519 	if (def_mount_opts & EXT4_DEFM_UID16)
1520 		set_opt(sbi->s_mount_opt, NO_UID32);
1521 #ifdef CONFIG_EXT4DEV_FS_XATTR
1522 	if (def_mount_opts & EXT4_DEFM_XATTR_USER)
1523 		set_opt(sbi->s_mount_opt, XATTR_USER);
1524 #endif
1525 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
1526 	if (def_mount_opts & EXT4_DEFM_ACL)
1527 		set_opt(sbi->s_mount_opt, POSIX_ACL);
1528 #endif
1529 	if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA)
1530 		sbi->s_mount_opt |= EXT4_MOUNT_JOURNAL_DATA;
1531 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_ORDERED)
1532 		sbi->s_mount_opt |= EXT4_MOUNT_ORDERED_DATA;
1533 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_WBACK)
1534 		sbi->s_mount_opt |= EXT4_MOUNT_WRITEBACK_DATA;
1535 
1536 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_PANIC)
1537 		set_opt(sbi->s_mount_opt, ERRORS_PANIC);
1538 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_RO)
1539 		set_opt(sbi->s_mount_opt, ERRORS_RO);
1540 	else
1541 		set_opt(sbi->s_mount_opt, ERRORS_CONT);
1542 
1543 	sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
1544 	sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
1545 
1546 	set_opt(sbi->s_mount_opt, RESERVATION);
1547 
1548 	if (!parse_options ((char *) data, sb, &journal_inum, &journal_devnum,
1549 			    NULL, 0))
1550 		goto failed_mount;
1551 
1552 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1553 		((sbi->s_mount_opt & EXT4_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1554 
1555 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
1556 	    (EXT4_HAS_COMPAT_FEATURE(sb, ~0U) ||
1557 	     EXT4_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
1558 	     EXT4_HAS_INCOMPAT_FEATURE(sb, ~0U)))
1559 		printk(KERN_WARNING
1560 		       "EXT4-fs warning: feature flags set on rev 0 fs, "
1561 		       "running e2fsck is recommended\n");
1562 	/*
1563 	 * Check feature flags regardless of the revision level, since we
1564 	 * previously didn't change the revision level when setting the flags,
1565 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
1566 	 */
1567 	features = EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT4_FEATURE_INCOMPAT_SUPP);
1568 	if (features) {
1569 		printk(KERN_ERR "EXT4-fs: %s: couldn't mount because of "
1570 		       "unsupported optional features (%x).\n",
1571 		       sb->s_id, le32_to_cpu(features));
1572 		goto failed_mount;
1573 	}
1574 	features = EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT4_FEATURE_RO_COMPAT_SUPP);
1575 	if (!(sb->s_flags & MS_RDONLY) && features) {
1576 		printk(KERN_ERR "EXT4-fs: %s: couldn't mount RDWR because of "
1577 		       "unsupported optional features (%x).\n",
1578 		       sb->s_id, le32_to_cpu(features));
1579 		goto failed_mount;
1580 	}
1581 	blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
1582 
1583 	if (blocksize < EXT4_MIN_BLOCK_SIZE ||
1584 	    blocksize > EXT4_MAX_BLOCK_SIZE) {
1585 		printk(KERN_ERR
1586 		       "EXT4-fs: Unsupported filesystem blocksize %d on %s.\n",
1587 		       blocksize, sb->s_id);
1588 		goto failed_mount;
1589 	}
1590 
1591 	hblock = bdev_hardsect_size(sb->s_bdev);
1592 	if (sb->s_blocksize != blocksize) {
1593 		/*
1594 		 * Make sure the blocksize for the filesystem is larger
1595 		 * than the hardware sectorsize for the machine.
1596 		 */
1597 		if (blocksize < hblock) {
1598 			printk(KERN_ERR "EXT4-fs: blocksize %d too small for "
1599 			       "device blocksize %d.\n", blocksize, hblock);
1600 			goto failed_mount;
1601 		}
1602 
1603 		brelse (bh);
1604 		sb_set_blocksize(sb, blocksize);
1605 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
1606 		offset = do_div(logical_sb_block, blocksize);
1607 		bh = sb_bread(sb, logical_sb_block);
1608 		if (!bh) {
1609 			printk(KERN_ERR
1610 			       "EXT4-fs: Can't read superblock on 2nd try.\n");
1611 			goto failed_mount;
1612 		}
1613 		es = (struct ext4_super_block *)(((char *)bh->b_data) + offset);
1614 		sbi->s_es = es;
1615 		if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
1616 			printk (KERN_ERR
1617 				"EXT4-fs: Magic mismatch, very weird !\n");
1618 			goto failed_mount;
1619 		}
1620 	}
1621 
1622 	sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits);
1623 
1624 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) {
1625 		sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE;
1626 		sbi->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
1627 	} else {
1628 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
1629 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
1630 		if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
1631 		    (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
1632 		    (sbi->s_inode_size > blocksize)) {
1633 			printk (KERN_ERR
1634 				"EXT4-fs: unsupported inode size: %d\n",
1635 				sbi->s_inode_size);
1636 			goto failed_mount;
1637 		}
1638 	}
1639 	sbi->s_frag_size = EXT4_MIN_FRAG_SIZE <<
1640 				   le32_to_cpu(es->s_log_frag_size);
1641 	if (blocksize != sbi->s_frag_size) {
1642 		printk(KERN_ERR
1643 		       "EXT4-fs: fragsize %lu != blocksize %u (unsupported)\n",
1644 		       sbi->s_frag_size, blocksize);
1645 		goto failed_mount;
1646 	}
1647 	sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
1648 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT)) {
1649 		if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT ||
1650 		    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
1651 		    sbi->s_desc_size & (sbi->s_desc_size - 1)) {
1652 			printk(KERN_ERR
1653 			       "EXT4-fs: unsupported descriptor size %lu\n",
1654 			       sbi->s_desc_size);
1655 			goto failed_mount;
1656 		}
1657 	} else
1658 		sbi->s_desc_size = EXT4_MIN_DESC_SIZE;
1659 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
1660 	sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
1661 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
1662 	if (EXT4_INODE_SIZE(sb) == 0)
1663 		goto cantfind_ext4;
1664 	sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
1665 	if (sbi->s_inodes_per_block == 0)
1666 		goto cantfind_ext4;
1667 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
1668 					sbi->s_inodes_per_block;
1669 	sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
1670 	sbi->s_sbh = bh;
1671 	sbi->s_mount_state = le16_to_cpu(es->s_state);
1672 	sbi->s_addr_per_block_bits = log2(EXT4_ADDR_PER_BLOCK(sb));
1673 	sbi->s_desc_per_block_bits = log2(EXT4_DESC_PER_BLOCK(sb));
1674 	for (i=0; i < 4; i++)
1675 		sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
1676 	sbi->s_def_hash_version = es->s_def_hash_version;
1677 
1678 	if (sbi->s_blocks_per_group > blocksize * 8) {
1679 		printk (KERN_ERR
1680 			"EXT4-fs: #blocks per group too big: %lu\n",
1681 			sbi->s_blocks_per_group);
1682 		goto failed_mount;
1683 	}
1684 	if (sbi->s_frags_per_group > blocksize * 8) {
1685 		printk (KERN_ERR
1686 			"EXT4-fs: #fragments per group too big: %lu\n",
1687 			sbi->s_frags_per_group);
1688 		goto failed_mount;
1689 	}
1690 	if (sbi->s_inodes_per_group > blocksize * 8) {
1691 		printk (KERN_ERR
1692 			"EXT4-fs: #inodes per group too big: %lu\n",
1693 			sbi->s_inodes_per_group);
1694 		goto failed_mount;
1695 	}
1696 
1697 	if (ext4_blocks_count(es) >
1698 		    (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1699 		printk(KERN_ERR "EXT4-fs: filesystem on %s:"
1700 			" too large to mount safely\n", sb->s_id);
1701 		if (sizeof(sector_t) < 8)
1702 			printk(KERN_WARNING "EXT4-fs: CONFIG_LBD not "
1703 					"enabled\n");
1704 		goto failed_mount;
1705 	}
1706 
1707 	if (EXT4_BLOCKS_PER_GROUP(sb) == 0)
1708 		goto cantfind_ext4;
1709 	blocks_count = (ext4_blocks_count(es) -
1710 			le32_to_cpu(es->s_first_data_block) +
1711 			EXT4_BLOCKS_PER_GROUP(sb) - 1);
1712 	do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
1713 	sbi->s_groups_count = blocks_count;
1714 	db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
1715 		   EXT4_DESC_PER_BLOCK(sb);
1716 	sbi->s_group_desc = kmalloc(db_count * sizeof (struct buffer_head *),
1717 				    GFP_KERNEL);
1718 	if (sbi->s_group_desc == NULL) {
1719 		printk (KERN_ERR "EXT4-fs: not enough memory\n");
1720 		goto failed_mount;
1721 	}
1722 
1723 	bgl_lock_init(&sbi->s_blockgroup_lock);
1724 
1725 	for (i = 0; i < db_count; i++) {
1726 		block = descriptor_loc(sb, logical_sb_block, i);
1727 		sbi->s_group_desc[i] = sb_bread(sb, block);
1728 		if (!sbi->s_group_desc[i]) {
1729 			printk (KERN_ERR "EXT4-fs: "
1730 				"can't read group descriptor %d\n", i);
1731 			db_count = i;
1732 			goto failed_mount2;
1733 		}
1734 	}
1735 	if (!ext4_check_descriptors (sb)) {
1736 		printk(KERN_ERR "EXT4-fs: group descriptors corrupted!\n");
1737 		goto failed_mount2;
1738 	}
1739 	sbi->s_gdb_count = db_count;
1740 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1741 	spin_lock_init(&sbi->s_next_gen_lock);
1742 
1743 	percpu_counter_init(&sbi->s_freeblocks_counter,
1744 		ext4_count_free_blocks(sb));
1745 	percpu_counter_init(&sbi->s_freeinodes_counter,
1746 		ext4_count_free_inodes(sb));
1747 	percpu_counter_init(&sbi->s_dirs_counter,
1748 		ext4_count_dirs(sb));
1749 
1750 	/* per fileystem reservation list head & lock */
1751 	spin_lock_init(&sbi->s_rsv_window_lock);
1752 	sbi->s_rsv_window_root = RB_ROOT;
1753 	/* Add a single, static dummy reservation to the start of the
1754 	 * reservation window list --- it gives us a placeholder for
1755 	 * append-at-start-of-list which makes the allocation logic
1756 	 * _much_ simpler. */
1757 	sbi->s_rsv_window_head.rsv_start = EXT4_RESERVE_WINDOW_NOT_ALLOCATED;
1758 	sbi->s_rsv_window_head.rsv_end = EXT4_RESERVE_WINDOW_NOT_ALLOCATED;
1759 	sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1760 	sbi->s_rsv_window_head.rsv_goal_size = 0;
1761 	ext4_rsv_window_add(sb, &sbi->s_rsv_window_head);
1762 
1763 	/*
1764 	 * set up enough so that it can read an inode
1765 	 */
1766 	sb->s_op = &ext4_sops;
1767 	sb->s_export_op = &ext4_export_ops;
1768 	sb->s_xattr = ext4_xattr_handlers;
1769 #ifdef CONFIG_QUOTA
1770 	sb->s_qcop = &ext4_qctl_operations;
1771 	sb->dq_op = &ext4_quota_operations;
1772 #endif
1773 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
1774 
1775 	sb->s_root = NULL;
1776 
1777 	needs_recovery = (es->s_last_orphan != 0 ||
1778 			  EXT4_HAS_INCOMPAT_FEATURE(sb,
1779 				    EXT4_FEATURE_INCOMPAT_RECOVER));
1780 
1781 	/*
1782 	 * The first inode we look at is the journal inode.  Don't try
1783 	 * root first: it may be modified in the journal!
1784 	 */
1785 	if (!test_opt(sb, NOLOAD) &&
1786 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
1787 		if (ext4_load_journal(sb, es, journal_devnum))
1788 			goto failed_mount3;
1789 	} else if (journal_inum) {
1790 		if (ext4_create_journal(sb, es, journal_inum))
1791 			goto failed_mount3;
1792 	} else {
1793 		if (!silent)
1794 			printk (KERN_ERR
1795 				"ext4: No journal on filesystem on %s\n",
1796 				sb->s_id);
1797 		goto failed_mount3;
1798 	}
1799 
1800 	/* We have now updated the journal if required, so we can
1801 	 * validate the data journaling mode. */
1802 	switch (test_opt(sb, DATA_FLAGS)) {
1803 	case 0:
1804 		/* No mode set, assume a default based on the journal
1805 		 * capabilities: ORDERED_DATA if the journal can
1806 		 * cope, else JOURNAL_DATA
1807 		 */
1808 		if (jbd2_journal_check_available_features
1809 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE))
1810 			set_opt(sbi->s_mount_opt, ORDERED_DATA);
1811 		else
1812 			set_opt(sbi->s_mount_opt, JOURNAL_DATA);
1813 		break;
1814 
1815 	case EXT4_MOUNT_ORDERED_DATA:
1816 	case EXT4_MOUNT_WRITEBACK_DATA:
1817 		if (!jbd2_journal_check_available_features
1818 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
1819 			printk(KERN_ERR "EXT4-fs: Journal does not support "
1820 			       "requested data journaling mode\n");
1821 			goto failed_mount4;
1822 		}
1823 	default:
1824 		break;
1825 	}
1826 
1827 	if (test_opt(sb, NOBH)) {
1828 		if (!(test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)) {
1829 			printk(KERN_WARNING "EXT4-fs: Ignoring nobh option - "
1830 				"its supported only with writeback mode\n");
1831 			clear_opt(sbi->s_mount_opt, NOBH);
1832 		}
1833 	}
1834 	/*
1835 	 * The jbd2_journal_load will have done any necessary log recovery,
1836 	 * so we can safely mount the rest of the filesystem now.
1837 	 */
1838 
1839 	root = iget(sb, EXT4_ROOT_INO);
1840 	sb->s_root = d_alloc_root(root);
1841 	if (!sb->s_root) {
1842 		printk(KERN_ERR "EXT4-fs: get root inode failed\n");
1843 		iput(root);
1844 		goto failed_mount4;
1845 	}
1846 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1847 		dput(sb->s_root);
1848 		sb->s_root = NULL;
1849 		printk(KERN_ERR "EXT4-fs: corrupt root inode, run e2fsck\n");
1850 		goto failed_mount4;
1851 	}
1852 
1853 	ext4_setup_super (sb, es, sb->s_flags & MS_RDONLY);
1854 	/*
1855 	 * akpm: core read_super() calls in here with the superblock locked.
1856 	 * That deadlocks, because orphan cleanup needs to lock the superblock
1857 	 * in numerous places.  Here we just pop the lock - it's relatively
1858 	 * harmless, because we are now ready to accept write_super() requests,
1859 	 * and aviro says that's the only reason for hanging onto the
1860 	 * superblock lock.
1861 	 */
1862 	EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
1863 	ext4_orphan_cleanup(sb, es);
1864 	EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
1865 	if (needs_recovery)
1866 		printk (KERN_INFO "EXT4-fs: recovery complete.\n");
1867 	ext4_mark_recovery_complete(sb, es);
1868 	printk (KERN_INFO "EXT4-fs: mounted filesystem with %s data mode.\n",
1869 		test_opt(sb,DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ? "journal":
1870 		test_opt(sb,DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA ? "ordered":
1871 		"writeback");
1872 
1873 	ext4_ext_init(sb);
1874 
1875 	lock_kernel();
1876 	return 0;
1877 
1878 cantfind_ext4:
1879 	if (!silent)
1880 		printk(KERN_ERR "VFS: Can't find ext4 filesystem on dev %s.\n",
1881 		       sb->s_id);
1882 	goto failed_mount;
1883 
1884 failed_mount4:
1885 	jbd2_journal_destroy(sbi->s_journal);
1886 failed_mount3:
1887 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
1888 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
1889 	percpu_counter_destroy(&sbi->s_dirs_counter);
1890 failed_mount2:
1891 	for (i = 0; i < db_count; i++)
1892 		brelse(sbi->s_group_desc[i]);
1893 	kfree(sbi->s_group_desc);
1894 failed_mount:
1895 #ifdef CONFIG_QUOTA
1896 	for (i = 0; i < MAXQUOTAS; i++)
1897 		kfree(sbi->s_qf_names[i]);
1898 #endif
1899 	ext4_blkdev_remove(sbi);
1900 	brelse(bh);
1901 out_fail:
1902 	sb->s_fs_info = NULL;
1903 	kfree(sbi);
1904 	lock_kernel();
1905 	return -EINVAL;
1906 }
1907 
1908 /*
1909  * Setup any per-fs journal parameters now.  We'll do this both on
1910  * initial mount, once the journal has been initialised but before we've
1911  * done any recovery; and again on any subsequent remount.
1912  */
1913 static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
1914 {
1915 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1916 
1917 	if (sbi->s_commit_interval)
1918 		journal->j_commit_interval = sbi->s_commit_interval;
1919 	/* We could also set up an ext4-specific default for the commit
1920 	 * interval here, but for now we'll just fall back to the jbd
1921 	 * default. */
1922 
1923 	spin_lock(&journal->j_state_lock);
1924 	if (test_opt(sb, BARRIER))
1925 		journal->j_flags |= JBD2_BARRIER;
1926 	else
1927 		journal->j_flags &= ~JBD2_BARRIER;
1928 	spin_unlock(&journal->j_state_lock);
1929 }
1930 
1931 static journal_t *ext4_get_journal(struct super_block *sb,
1932 				   unsigned int journal_inum)
1933 {
1934 	struct inode *journal_inode;
1935 	journal_t *journal;
1936 
1937 	/* First, test for the existence of a valid inode on disk.  Bad
1938 	 * things happen if we iget() an unused inode, as the subsequent
1939 	 * iput() will try to delete it. */
1940 
1941 	journal_inode = iget(sb, journal_inum);
1942 	if (!journal_inode) {
1943 		printk(KERN_ERR "EXT4-fs: no journal found.\n");
1944 		return NULL;
1945 	}
1946 	if (!journal_inode->i_nlink) {
1947 		make_bad_inode(journal_inode);
1948 		iput(journal_inode);
1949 		printk(KERN_ERR "EXT4-fs: journal inode is deleted.\n");
1950 		return NULL;
1951 	}
1952 
1953 	jbd_debug(2, "Journal inode found at %p: %Ld bytes\n",
1954 		  journal_inode, journal_inode->i_size);
1955 	if (is_bad_inode(journal_inode) || !S_ISREG(journal_inode->i_mode)) {
1956 		printk(KERN_ERR "EXT4-fs: invalid journal inode.\n");
1957 		iput(journal_inode);
1958 		return NULL;
1959 	}
1960 
1961 	journal = jbd2_journal_init_inode(journal_inode);
1962 	if (!journal) {
1963 		printk(KERN_ERR "EXT4-fs: Could not load journal inode\n");
1964 		iput(journal_inode);
1965 		return NULL;
1966 	}
1967 	journal->j_private = sb;
1968 	ext4_init_journal_params(sb, journal);
1969 	return journal;
1970 }
1971 
1972 static journal_t *ext4_get_dev_journal(struct super_block *sb,
1973 				       dev_t j_dev)
1974 {
1975 	struct buffer_head * bh;
1976 	journal_t *journal;
1977 	ext4_fsblk_t start;
1978 	ext4_fsblk_t len;
1979 	int hblock, blocksize;
1980 	ext4_fsblk_t sb_block;
1981 	unsigned long offset;
1982 	struct ext4_super_block * es;
1983 	struct block_device *bdev;
1984 
1985 	bdev = ext4_blkdev_get(j_dev);
1986 	if (bdev == NULL)
1987 		return NULL;
1988 
1989 	if (bd_claim(bdev, sb)) {
1990 		printk(KERN_ERR
1991 		        "EXT4: failed to claim external journal device.\n");
1992 		blkdev_put(bdev);
1993 		return NULL;
1994 	}
1995 
1996 	blocksize = sb->s_blocksize;
1997 	hblock = bdev_hardsect_size(bdev);
1998 	if (blocksize < hblock) {
1999 		printk(KERN_ERR
2000 			"EXT4-fs: blocksize too small for journal device.\n");
2001 		goto out_bdev;
2002 	}
2003 
2004 	sb_block = EXT4_MIN_BLOCK_SIZE / blocksize;
2005 	offset = EXT4_MIN_BLOCK_SIZE % blocksize;
2006 	set_blocksize(bdev, blocksize);
2007 	if (!(bh = __bread(bdev, sb_block, blocksize))) {
2008 		printk(KERN_ERR "EXT4-fs: couldn't read superblock of "
2009 		       "external journal\n");
2010 		goto out_bdev;
2011 	}
2012 
2013 	es = (struct ext4_super_block *) (((char *)bh->b_data) + offset);
2014 	if ((le16_to_cpu(es->s_magic) != EXT4_SUPER_MAGIC) ||
2015 	    !(le32_to_cpu(es->s_feature_incompat) &
2016 	      EXT4_FEATURE_INCOMPAT_JOURNAL_DEV)) {
2017 		printk(KERN_ERR "EXT4-fs: external journal has "
2018 					"bad superblock\n");
2019 		brelse(bh);
2020 		goto out_bdev;
2021 	}
2022 
2023 	if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
2024 		printk(KERN_ERR "EXT4-fs: journal UUID does not match\n");
2025 		brelse(bh);
2026 		goto out_bdev;
2027 	}
2028 
2029 	len = ext4_blocks_count(es);
2030 	start = sb_block + 1;
2031 	brelse(bh);	/* we're done with the superblock */
2032 
2033 	journal = jbd2_journal_init_dev(bdev, sb->s_bdev,
2034 					start, len, blocksize);
2035 	if (!journal) {
2036 		printk(KERN_ERR "EXT4-fs: failed to create device journal\n");
2037 		goto out_bdev;
2038 	}
2039 	journal->j_private = sb;
2040 	ll_rw_block(READ, 1, &journal->j_sb_buffer);
2041 	wait_on_buffer(journal->j_sb_buffer);
2042 	if (!buffer_uptodate(journal->j_sb_buffer)) {
2043 		printk(KERN_ERR "EXT4-fs: I/O error on journal device\n");
2044 		goto out_journal;
2045 	}
2046 	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
2047 		printk(KERN_ERR "EXT4-fs: External journal has more than one "
2048 					"user (unsupported) - %d\n",
2049 			be32_to_cpu(journal->j_superblock->s_nr_users));
2050 		goto out_journal;
2051 	}
2052 	EXT4_SB(sb)->journal_bdev = bdev;
2053 	ext4_init_journal_params(sb, journal);
2054 	return journal;
2055 out_journal:
2056 	jbd2_journal_destroy(journal);
2057 out_bdev:
2058 	ext4_blkdev_put(bdev);
2059 	return NULL;
2060 }
2061 
2062 static int ext4_load_journal(struct super_block *sb,
2063 			     struct ext4_super_block *es,
2064 			     unsigned long journal_devnum)
2065 {
2066 	journal_t *journal;
2067 	unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
2068 	dev_t journal_dev;
2069 	int err = 0;
2070 	int really_read_only;
2071 
2072 	if (journal_devnum &&
2073 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
2074 		printk(KERN_INFO "EXT4-fs: external journal device major/minor "
2075 			"numbers have changed\n");
2076 		journal_dev = new_decode_dev(journal_devnum);
2077 	} else
2078 		journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));
2079 
2080 	really_read_only = bdev_read_only(sb->s_bdev);
2081 
2082 	/*
2083 	 * Are we loading a blank journal or performing recovery after a
2084 	 * crash?  For recovery, we need to check in advance whether we
2085 	 * can get read-write access to the device.
2086 	 */
2087 
2088 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
2089 		if (sb->s_flags & MS_RDONLY) {
2090 			printk(KERN_INFO "EXT4-fs: INFO: recovery "
2091 					"required on readonly filesystem.\n");
2092 			if (really_read_only) {
2093 				printk(KERN_ERR "EXT4-fs: write access "
2094 					"unavailable, cannot proceed.\n");
2095 				return -EROFS;
2096 			}
2097 			printk (KERN_INFO "EXT4-fs: write access will "
2098 					"be enabled during recovery.\n");
2099 		}
2100 	}
2101 
2102 	if (journal_inum && journal_dev) {
2103 		printk(KERN_ERR "EXT4-fs: filesystem has both journal "
2104 		       "and inode journals!\n");
2105 		return -EINVAL;
2106 	}
2107 
2108 	if (journal_inum) {
2109 		if (!(journal = ext4_get_journal(sb, journal_inum)))
2110 			return -EINVAL;
2111 	} else {
2112 		if (!(journal = ext4_get_dev_journal(sb, journal_dev)))
2113 			return -EINVAL;
2114 	}
2115 
2116 	if (!really_read_only && test_opt(sb, UPDATE_JOURNAL)) {
2117 		err = jbd2_journal_update_format(journal);
2118 		if (err)  {
2119 			printk(KERN_ERR "EXT4-fs: error updating journal.\n");
2120 			jbd2_journal_destroy(journal);
2121 			return err;
2122 		}
2123 	}
2124 
2125 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER))
2126 		err = jbd2_journal_wipe(journal, !really_read_only);
2127 	if (!err)
2128 		err = jbd2_journal_load(journal);
2129 
2130 	if (err) {
2131 		printk(KERN_ERR "EXT4-fs: error loading journal.\n");
2132 		jbd2_journal_destroy(journal);
2133 		return err;
2134 	}
2135 
2136 	EXT4_SB(sb)->s_journal = journal;
2137 	ext4_clear_journal_err(sb, es);
2138 
2139 	if (journal_devnum &&
2140 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
2141 		es->s_journal_dev = cpu_to_le32(journal_devnum);
2142 		sb->s_dirt = 1;
2143 
2144 		/* Make sure we flush the recovery flag to disk. */
2145 		ext4_commit_super(sb, es, 1);
2146 	}
2147 
2148 	return 0;
2149 }
2150 
2151 static int ext4_create_journal(struct super_block * sb,
2152 			       struct ext4_super_block * es,
2153 			       unsigned int journal_inum)
2154 {
2155 	journal_t *journal;
2156 
2157 	if (sb->s_flags & MS_RDONLY) {
2158 		printk(KERN_ERR "EXT4-fs: readonly filesystem when trying to "
2159 				"create journal.\n");
2160 		return -EROFS;
2161 	}
2162 
2163 	if (!(journal = ext4_get_journal(sb, journal_inum)))
2164 		return -EINVAL;
2165 
2166 	printk(KERN_INFO "EXT4-fs: creating new journal on inode %u\n",
2167 	       journal_inum);
2168 
2169 	if (jbd2_journal_create(journal)) {
2170 		printk(KERN_ERR "EXT4-fs: error creating journal.\n");
2171 		jbd2_journal_destroy(journal);
2172 		return -EIO;
2173 	}
2174 
2175 	EXT4_SB(sb)->s_journal = journal;
2176 
2177 	ext4_update_dynamic_rev(sb);
2178 	EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
2179 	EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL);
2180 
2181 	es->s_journal_inum = cpu_to_le32(journal_inum);
2182 	sb->s_dirt = 1;
2183 
2184 	/* Make sure we flush the recovery flag to disk. */
2185 	ext4_commit_super(sb, es, 1);
2186 
2187 	return 0;
2188 }
2189 
2190 static void ext4_commit_super (struct super_block * sb,
2191 			       struct ext4_super_block * es,
2192 			       int sync)
2193 {
2194 	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
2195 
2196 	if (!sbh)
2197 		return;
2198 	es->s_wtime = cpu_to_le32(get_seconds());
2199 	ext4_free_blocks_count_set(es, ext4_count_free_blocks(sb));
2200 	es->s_free_inodes_count = cpu_to_le32(ext4_count_free_inodes(sb));
2201 	BUFFER_TRACE(sbh, "marking dirty");
2202 	mark_buffer_dirty(sbh);
2203 	if (sync)
2204 		sync_dirty_buffer(sbh);
2205 }
2206 
2207 
2208 /*
2209  * Have we just finished recovery?  If so, and if we are mounting (or
2210  * remounting) the filesystem readonly, then we will end up with a
2211  * consistent fs on disk.  Record that fact.
2212  */
2213 static void ext4_mark_recovery_complete(struct super_block * sb,
2214 					struct ext4_super_block * es)
2215 {
2216 	journal_t *journal = EXT4_SB(sb)->s_journal;
2217 
2218 	jbd2_journal_lock_updates(journal);
2219 	jbd2_journal_flush(journal);
2220 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER) &&
2221 	    sb->s_flags & MS_RDONLY) {
2222 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
2223 		sb->s_dirt = 0;
2224 		ext4_commit_super(sb, es, 1);
2225 	}
2226 	jbd2_journal_unlock_updates(journal);
2227 }
2228 
2229 /*
2230  * If we are mounting (or read-write remounting) a filesystem whose journal
2231  * has recorded an error from a previous lifetime, move that error to the
2232  * main filesystem now.
2233  */
2234 static void ext4_clear_journal_err(struct super_block * sb,
2235 				   struct ext4_super_block * es)
2236 {
2237 	journal_t *journal;
2238 	int j_errno;
2239 	const char *errstr;
2240 
2241 	journal = EXT4_SB(sb)->s_journal;
2242 
2243 	/*
2244 	 * Now check for any error status which may have been recorded in the
2245 	 * journal by a prior ext4_error() or ext4_abort()
2246 	 */
2247 
2248 	j_errno = jbd2_journal_errno(journal);
2249 	if (j_errno) {
2250 		char nbuf[16];
2251 
2252 		errstr = ext4_decode_error(sb, j_errno, nbuf);
2253 		ext4_warning(sb, __FUNCTION__, "Filesystem error recorded "
2254 			     "from previous mount: %s", errstr);
2255 		ext4_warning(sb, __FUNCTION__, "Marking fs in need of "
2256 			     "filesystem check.");
2257 
2258 		EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
2259 		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
2260 		ext4_commit_super (sb, es, 1);
2261 
2262 		jbd2_journal_clear_err(journal);
2263 	}
2264 }
2265 
2266 /*
2267  * Force the running and committing transactions to commit,
2268  * and wait on the commit.
2269  */
2270 int ext4_force_commit(struct super_block *sb)
2271 {
2272 	journal_t *journal;
2273 	int ret;
2274 
2275 	if (sb->s_flags & MS_RDONLY)
2276 		return 0;
2277 
2278 	journal = EXT4_SB(sb)->s_journal;
2279 	sb->s_dirt = 0;
2280 	ret = ext4_journal_force_commit(journal);
2281 	return ret;
2282 }
2283 
2284 /*
2285  * Ext4 always journals updates to the superblock itself, so we don't
2286  * have to propagate any other updates to the superblock on disk at this
2287  * point.  Just start an async writeback to get the buffers on their way
2288  * to the disk.
2289  *
2290  * This implicitly triggers the writebehind on sync().
2291  */
2292 
2293 static void ext4_write_super (struct super_block * sb)
2294 {
2295 	if (mutex_trylock(&sb->s_lock) != 0)
2296 		BUG();
2297 	sb->s_dirt = 0;
2298 }
2299 
2300 static int ext4_sync_fs(struct super_block *sb, int wait)
2301 {
2302 	tid_t target;
2303 
2304 	sb->s_dirt = 0;
2305 	if (jbd2_journal_start_commit(EXT4_SB(sb)->s_journal, &target)) {
2306 		if (wait)
2307 			jbd2_log_wait_commit(EXT4_SB(sb)->s_journal, target);
2308 	}
2309 	return 0;
2310 }
2311 
2312 /*
2313  * LVM calls this function before a (read-only) snapshot is created.  This
2314  * gives us a chance to flush the journal completely and mark the fs clean.
2315  */
2316 static void ext4_write_super_lockfs(struct super_block *sb)
2317 {
2318 	sb->s_dirt = 0;
2319 
2320 	if (!(sb->s_flags & MS_RDONLY)) {
2321 		journal_t *journal = EXT4_SB(sb)->s_journal;
2322 
2323 		/* Now we set up the journal barrier. */
2324 		jbd2_journal_lock_updates(journal);
2325 		jbd2_journal_flush(journal);
2326 
2327 		/* Journal blocked and flushed, clear needs_recovery flag. */
2328 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
2329 		ext4_commit_super(sb, EXT4_SB(sb)->s_es, 1);
2330 	}
2331 }
2332 
2333 /*
2334  * Called by LVM after the snapshot is done.  We need to reset the RECOVER
2335  * flag here, even though the filesystem is not technically dirty yet.
2336  */
2337 static void ext4_unlockfs(struct super_block *sb)
2338 {
2339 	if (!(sb->s_flags & MS_RDONLY)) {
2340 		lock_super(sb);
2341 		/* Reser the needs_recovery flag before the fs is unlocked. */
2342 		EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
2343 		ext4_commit_super(sb, EXT4_SB(sb)->s_es, 1);
2344 		unlock_super(sb);
2345 		jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
2346 	}
2347 }
2348 
2349 static int ext4_remount (struct super_block * sb, int * flags, char * data)
2350 {
2351 	struct ext4_super_block * es;
2352 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2353 	ext4_fsblk_t n_blocks_count = 0;
2354 	unsigned long old_sb_flags;
2355 	struct ext4_mount_options old_opts;
2356 	int err;
2357 #ifdef CONFIG_QUOTA
2358 	int i;
2359 #endif
2360 
2361 	/* Store the original options */
2362 	old_sb_flags = sb->s_flags;
2363 	old_opts.s_mount_opt = sbi->s_mount_opt;
2364 	old_opts.s_resuid = sbi->s_resuid;
2365 	old_opts.s_resgid = sbi->s_resgid;
2366 	old_opts.s_commit_interval = sbi->s_commit_interval;
2367 #ifdef CONFIG_QUOTA
2368 	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
2369 	for (i = 0; i < MAXQUOTAS; i++)
2370 		old_opts.s_qf_names[i] = sbi->s_qf_names[i];
2371 #endif
2372 
2373 	/*
2374 	 * Allow the "check" option to be passed as a remount option.
2375 	 */
2376 	if (!parse_options(data, sb, NULL, NULL, &n_blocks_count, 1)) {
2377 		err = -EINVAL;
2378 		goto restore_opts;
2379 	}
2380 
2381 	if (sbi->s_mount_opt & EXT4_MOUNT_ABORT)
2382 		ext4_abort(sb, __FUNCTION__, "Abort forced by user");
2383 
2384 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
2385 		((sbi->s_mount_opt & EXT4_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
2386 
2387 	es = sbi->s_es;
2388 
2389 	ext4_init_journal_params(sb, sbi->s_journal);
2390 
2391 	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY) ||
2392 		n_blocks_count > ext4_blocks_count(es)) {
2393 		if (sbi->s_mount_opt & EXT4_MOUNT_ABORT) {
2394 			err = -EROFS;
2395 			goto restore_opts;
2396 		}
2397 
2398 		if (*flags & MS_RDONLY) {
2399 			/*
2400 			 * First of all, the unconditional stuff we have to do
2401 			 * to disable replay of the journal when we next remount
2402 			 */
2403 			sb->s_flags |= MS_RDONLY;
2404 
2405 			/*
2406 			 * OK, test if we are remounting a valid rw partition
2407 			 * readonly, and if so set the rdonly flag and then
2408 			 * mark the partition as valid again.
2409 			 */
2410 			if (!(es->s_state & cpu_to_le16(EXT4_VALID_FS)) &&
2411 			    (sbi->s_mount_state & EXT4_VALID_FS))
2412 				es->s_state = cpu_to_le16(sbi->s_mount_state);
2413 
2414 			ext4_mark_recovery_complete(sb, es);
2415 		} else {
2416 			__le32 ret;
2417 			if ((ret = EXT4_HAS_RO_COMPAT_FEATURE(sb,
2418 					~EXT4_FEATURE_RO_COMPAT_SUPP))) {
2419 				printk(KERN_WARNING "EXT4-fs: %s: couldn't "
2420 				       "remount RDWR because of unsupported "
2421 				       "optional features (%x).\n",
2422 				       sb->s_id, le32_to_cpu(ret));
2423 				err = -EROFS;
2424 				goto restore_opts;
2425 			}
2426 
2427 			/*
2428 			 * If we have an unprocessed orphan list hanging
2429 			 * around from a previously readonly bdev mount,
2430 			 * require a full umount/remount for now.
2431 			 */
2432 			if (es->s_last_orphan) {
2433 				printk(KERN_WARNING "EXT4-fs: %s: couldn't "
2434 				       "remount RDWR because of unprocessed "
2435 				       "orphan inode list.  Please "
2436 				       "umount/remount instead.\n",
2437 				       sb->s_id);
2438 				err = -EINVAL;
2439 				goto restore_opts;
2440 			}
2441 
2442 			/*
2443 			 * Mounting a RDONLY partition read-write, so reread
2444 			 * and store the current valid flag.  (It may have
2445 			 * been changed by e2fsck since we originally mounted
2446 			 * the partition.)
2447 			 */
2448 			ext4_clear_journal_err(sb, es);
2449 			sbi->s_mount_state = le16_to_cpu(es->s_state);
2450 			if ((err = ext4_group_extend(sb, es, n_blocks_count)))
2451 				goto restore_opts;
2452 			if (!ext4_setup_super (sb, es, 0))
2453 				sb->s_flags &= ~MS_RDONLY;
2454 		}
2455 	}
2456 #ifdef CONFIG_QUOTA
2457 	/* Release old quota file names */
2458 	for (i = 0; i < MAXQUOTAS; i++)
2459 		if (old_opts.s_qf_names[i] &&
2460 		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
2461 			kfree(old_opts.s_qf_names[i]);
2462 #endif
2463 	return 0;
2464 restore_opts:
2465 	sb->s_flags = old_sb_flags;
2466 	sbi->s_mount_opt = old_opts.s_mount_opt;
2467 	sbi->s_resuid = old_opts.s_resuid;
2468 	sbi->s_resgid = old_opts.s_resgid;
2469 	sbi->s_commit_interval = old_opts.s_commit_interval;
2470 #ifdef CONFIG_QUOTA
2471 	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
2472 	for (i = 0; i < MAXQUOTAS; i++) {
2473 		if (sbi->s_qf_names[i] &&
2474 		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
2475 			kfree(sbi->s_qf_names[i]);
2476 		sbi->s_qf_names[i] = old_opts.s_qf_names[i];
2477 	}
2478 #endif
2479 	return err;
2480 }
2481 
2482 static int ext4_statfs (struct dentry * dentry, struct kstatfs * buf)
2483 {
2484 	struct super_block *sb = dentry->d_sb;
2485 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2486 	struct ext4_super_block *es = sbi->s_es;
2487 	ext4_fsblk_t overhead;
2488 	int i;
2489 	u64 fsid;
2490 
2491 	if (test_opt (sb, MINIX_DF))
2492 		overhead = 0;
2493 	else {
2494 		unsigned long ngroups;
2495 		ngroups = EXT4_SB(sb)->s_groups_count;
2496 		smp_rmb();
2497 
2498 		/*
2499 		 * Compute the overhead (FS structures)
2500 		 */
2501 
2502 		/*
2503 		 * All of the blocks before first_data_block are
2504 		 * overhead
2505 		 */
2506 		overhead = le32_to_cpu(es->s_first_data_block);
2507 
2508 		/*
2509 		 * Add the overhead attributed to the superblock and
2510 		 * block group descriptors.  If the sparse superblocks
2511 		 * feature is turned on, then not all groups have this.
2512 		 */
2513 		for (i = 0; i < ngroups; i++) {
2514 			overhead += ext4_bg_has_super(sb, i) +
2515 				ext4_bg_num_gdb(sb, i);
2516 			cond_resched();
2517 		}
2518 
2519 		/*
2520 		 * Every block group has an inode bitmap, a block
2521 		 * bitmap, and an inode table.
2522 		 */
2523 		overhead += (ngroups * (2 + EXT4_SB(sb)->s_itb_per_group));
2524 	}
2525 
2526 	buf->f_type = EXT4_SUPER_MAGIC;
2527 	buf->f_bsize = sb->s_blocksize;
2528 	buf->f_blocks = ext4_blocks_count(es) - overhead;
2529 	buf->f_bfree = percpu_counter_sum(&sbi->s_freeblocks_counter);
2530 	buf->f_bavail = buf->f_bfree - ext4_r_blocks_count(es);
2531 	if (buf->f_bfree < ext4_r_blocks_count(es))
2532 		buf->f_bavail = 0;
2533 	buf->f_files = le32_to_cpu(es->s_inodes_count);
2534 	buf->f_ffree = percpu_counter_sum(&sbi->s_freeinodes_counter);
2535 	buf->f_namelen = EXT4_NAME_LEN;
2536 	fsid = le64_to_cpup((void *)es->s_uuid) ^
2537 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
2538 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
2539 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
2540 	return 0;
2541 }
2542 
2543 /* Helper function for writing quotas on sync - we need to start transaction before quota file
2544  * is locked for write. Otherwise the are possible deadlocks:
2545  * Process 1                         Process 2
2546  * ext4_create()                     quota_sync()
2547  *   jbd2_journal_start()                   write_dquot()
2548  *   DQUOT_INIT()                        down(dqio_mutex)
2549  *     down(dqio_mutex)                    jbd2_journal_start()
2550  *
2551  */
2552 
2553 #ifdef CONFIG_QUOTA
2554 
2555 static inline struct inode *dquot_to_inode(struct dquot *dquot)
2556 {
2557 	return sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
2558 }
2559 
2560 static int ext4_dquot_initialize(struct inode *inode, int type)
2561 {
2562 	handle_t *handle;
2563 	int ret, err;
2564 
2565 	/* We may create quota structure so we need to reserve enough blocks */
2566 	handle = ext4_journal_start(inode, 2*EXT4_QUOTA_INIT_BLOCKS(inode->i_sb));
2567 	if (IS_ERR(handle))
2568 		return PTR_ERR(handle);
2569 	ret = dquot_initialize(inode, type);
2570 	err = ext4_journal_stop(handle);
2571 	if (!ret)
2572 		ret = err;
2573 	return ret;
2574 }
2575 
2576 static int ext4_dquot_drop(struct inode *inode)
2577 {
2578 	handle_t *handle;
2579 	int ret, err;
2580 
2581 	/* We may delete quota structure so we need to reserve enough blocks */
2582 	handle = ext4_journal_start(inode, 2*EXT4_QUOTA_DEL_BLOCKS(inode->i_sb));
2583 	if (IS_ERR(handle))
2584 		return PTR_ERR(handle);
2585 	ret = dquot_drop(inode);
2586 	err = ext4_journal_stop(handle);
2587 	if (!ret)
2588 		ret = err;
2589 	return ret;
2590 }
2591 
2592 static int ext4_write_dquot(struct dquot *dquot)
2593 {
2594 	int ret, err;
2595 	handle_t *handle;
2596 	struct inode *inode;
2597 
2598 	inode = dquot_to_inode(dquot);
2599 	handle = ext4_journal_start(inode,
2600 					EXT4_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
2601 	if (IS_ERR(handle))
2602 		return PTR_ERR(handle);
2603 	ret = dquot_commit(dquot);
2604 	err = ext4_journal_stop(handle);
2605 	if (!ret)
2606 		ret = err;
2607 	return ret;
2608 }
2609 
2610 static int ext4_acquire_dquot(struct dquot *dquot)
2611 {
2612 	int ret, err;
2613 	handle_t *handle;
2614 
2615 	handle = ext4_journal_start(dquot_to_inode(dquot),
2616 					EXT4_QUOTA_INIT_BLOCKS(dquot->dq_sb));
2617 	if (IS_ERR(handle))
2618 		return PTR_ERR(handle);
2619 	ret = dquot_acquire(dquot);
2620 	err = ext4_journal_stop(handle);
2621 	if (!ret)
2622 		ret = err;
2623 	return ret;
2624 }
2625 
2626 static int ext4_release_dquot(struct dquot *dquot)
2627 {
2628 	int ret, err;
2629 	handle_t *handle;
2630 
2631 	handle = ext4_journal_start(dquot_to_inode(dquot),
2632 					EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
2633 	if (IS_ERR(handle))
2634 		return PTR_ERR(handle);
2635 	ret = dquot_release(dquot);
2636 	err = ext4_journal_stop(handle);
2637 	if (!ret)
2638 		ret = err;
2639 	return ret;
2640 }
2641 
2642 static int ext4_mark_dquot_dirty(struct dquot *dquot)
2643 {
2644 	/* Are we journalling quotas? */
2645 	if (EXT4_SB(dquot->dq_sb)->s_qf_names[USRQUOTA] ||
2646 	    EXT4_SB(dquot->dq_sb)->s_qf_names[GRPQUOTA]) {
2647 		dquot_mark_dquot_dirty(dquot);
2648 		return ext4_write_dquot(dquot);
2649 	} else {
2650 		return dquot_mark_dquot_dirty(dquot);
2651 	}
2652 }
2653 
2654 static int ext4_write_info(struct super_block *sb, int type)
2655 {
2656 	int ret, err;
2657 	handle_t *handle;
2658 
2659 	/* Data block + inode block */
2660 	handle = ext4_journal_start(sb->s_root->d_inode, 2);
2661 	if (IS_ERR(handle))
2662 		return PTR_ERR(handle);
2663 	ret = dquot_commit_info(sb, type);
2664 	err = ext4_journal_stop(handle);
2665 	if (!ret)
2666 		ret = err;
2667 	return ret;
2668 }
2669 
2670 /*
2671  * Turn on quotas during mount time - we need to find
2672  * the quota file and such...
2673  */
2674 static int ext4_quota_on_mount(struct super_block *sb, int type)
2675 {
2676 	return vfs_quota_on_mount(sb, EXT4_SB(sb)->s_qf_names[type],
2677 			EXT4_SB(sb)->s_jquota_fmt, type);
2678 }
2679 
2680 /*
2681  * Standard function to be called on quota_on
2682  */
2683 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
2684 			 char *path)
2685 {
2686 	int err;
2687 	struct nameidata nd;
2688 
2689 	if (!test_opt(sb, QUOTA))
2690 		return -EINVAL;
2691 	/* Not journalling quota? */
2692 	if (!EXT4_SB(sb)->s_qf_names[USRQUOTA] &&
2693 	    !EXT4_SB(sb)->s_qf_names[GRPQUOTA])
2694 		return vfs_quota_on(sb, type, format_id, path);
2695 	err = path_lookup(path, LOOKUP_FOLLOW, &nd);
2696 	if (err)
2697 		return err;
2698 	/* Quotafile not on the same filesystem? */
2699 	if (nd.mnt->mnt_sb != sb) {
2700 		path_release(&nd);
2701 		return -EXDEV;
2702 	}
2703 	/* Quotafile not of fs root? */
2704 	if (nd.dentry->d_parent->d_inode != sb->s_root->d_inode)
2705 		printk(KERN_WARNING
2706 			"EXT4-fs: Quota file not on filesystem root. "
2707 			"Journalled quota will not work.\n");
2708 	path_release(&nd);
2709 	return vfs_quota_on(sb, type, format_id, path);
2710 }
2711 
2712 /* Read data from quotafile - avoid pagecache and such because we cannot afford
2713  * acquiring the locks... As quota files are never truncated and quota code
2714  * itself serializes the operations (and noone else should touch the files)
2715  * we don't have to be afraid of races */
2716 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
2717 			       size_t len, loff_t off)
2718 {
2719 	struct inode *inode = sb_dqopt(sb)->files[type];
2720 	sector_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
2721 	int err = 0;
2722 	int offset = off & (sb->s_blocksize - 1);
2723 	int tocopy;
2724 	size_t toread;
2725 	struct buffer_head *bh;
2726 	loff_t i_size = i_size_read(inode);
2727 
2728 	if (off > i_size)
2729 		return 0;
2730 	if (off+len > i_size)
2731 		len = i_size-off;
2732 	toread = len;
2733 	while (toread > 0) {
2734 		tocopy = sb->s_blocksize - offset < toread ?
2735 				sb->s_blocksize - offset : toread;
2736 		bh = ext4_bread(NULL, inode, blk, 0, &err);
2737 		if (err)
2738 			return err;
2739 		if (!bh)	/* A hole? */
2740 			memset(data, 0, tocopy);
2741 		else
2742 			memcpy(data, bh->b_data+offset, tocopy);
2743 		brelse(bh);
2744 		offset = 0;
2745 		toread -= tocopy;
2746 		data += tocopy;
2747 		blk++;
2748 	}
2749 	return len;
2750 }
2751 
2752 /* Write to quotafile (we know the transaction is already started and has
2753  * enough credits) */
2754 static ssize_t ext4_quota_write(struct super_block *sb, int type,
2755 				const char *data, size_t len, loff_t off)
2756 {
2757 	struct inode *inode = sb_dqopt(sb)->files[type];
2758 	sector_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
2759 	int err = 0;
2760 	int offset = off & (sb->s_blocksize - 1);
2761 	int tocopy;
2762 	int journal_quota = EXT4_SB(sb)->s_qf_names[type] != NULL;
2763 	size_t towrite = len;
2764 	struct buffer_head *bh;
2765 	handle_t *handle = journal_current_handle();
2766 
2767 	mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
2768 	while (towrite > 0) {
2769 		tocopy = sb->s_blocksize - offset < towrite ?
2770 				sb->s_blocksize - offset : towrite;
2771 		bh = ext4_bread(handle, inode, blk, 1, &err);
2772 		if (!bh)
2773 			goto out;
2774 		if (journal_quota) {
2775 			err = ext4_journal_get_write_access(handle, bh);
2776 			if (err) {
2777 				brelse(bh);
2778 				goto out;
2779 			}
2780 		}
2781 		lock_buffer(bh);
2782 		memcpy(bh->b_data+offset, data, tocopy);
2783 		flush_dcache_page(bh->b_page);
2784 		unlock_buffer(bh);
2785 		if (journal_quota)
2786 			err = ext4_journal_dirty_metadata(handle, bh);
2787 		else {
2788 			/* Always do at least ordered writes for quotas */
2789 			err = ext4_journal_dirty_data(handle, bh);
2790 			mark_buffer_dirty(bh);
2791 		}
2792 		brelse(bh);
2793 		if (err)
2794 			goto out;
2795 		offset = 0;
2796 		towrite -= tocopy;
2797 		data += tocopy;
2798 		blk++;
2799 	}
2800 out:
2801 	if (len == towrite)
2802 		return err;
2803 	if (inode->i_size < off+len-towrite) {
2804 		i_size_write(inode, off+len-towrite);
2805 		EXT4_I(inode)->i_disksize = inode->i_size;
2806 	}
2807 	inode->i_version++;
2808 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
2809 	ext4_mark_inode_dirty(handle, inode);
2810 	mutex_unlock(&inode->i_mutex);
2811 	return len - towrite;
2812 }
2813 
2814 #endif
2815 
2816 static int ext4_get_sb(struct file_system_type *fs_type,
2817 	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
2818 {
2819 	return get_sb_bdev(fs_type, flags, dev_name, data, ext4_fill_super, mnt);
2820 }
2821 
2822 static struct file_system_type ext4dev_fs_type = {
2823 	.owner		= THIS_MODULE,
2824 	.name		= "ext4dev",
2825 	.get_sb		= ext4_get_sb,
2826 	.kill_sb	= kill_block_super,
2827 	.fs_flags	= FS_REQUIRES_DEV,
2828 };
2829 
2830 static int __init init_ext4_fs(void)
2831 {
2832 	int err = init_ext4_xattr();
2833 	if (err)
2834 		return err;
2835 	err = init_inodecache();
2836 	if (err)
2837 		goto out1;
2838 	err = register_filesystem(&ext4dev_fs_type);
2839 	if (err)
2840 		goto out;
2841 	return 0;
2842 out:
2843 	destroy_inodecache();
2844 out1:
2845 	exit_ext4_xattr();
2846 	return err;
2847 }
2848 
2849 static void __exit exit_ext4_fs(void)
2850 {
2851 	unregister_filesystem(&ext4dev_fs_type);
2852 	destroy_inodecache();
2853 	exit_ext4_xattr();
2854 }
2855 
2856 MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
2857 MODULE_DESCRIPTION("Fourth Extended Filesystem with extents");
2858 MODULE_LICENSE("GPL");
2859 module_init(init_ext4_fs)
2860 module_exit(exit_ext4_fs)
2861