xref: /linux/fs/ext4/super.c (revision 44a2db43eb715b54618bf01520cc5d46376cdbe2)
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/exportfs.h>
33 #include <linux/vfs.h>
34 #include <linux/random.h>
35 #include <linux/mount.h>
36 #include <linux/namei.h>
37 #include <linux/quotaops.h>
38 #include <linux/seq_file.h>
39 #include <linux/log2.h>
40 
41 #include <asm/uaccess.h>
42 
43 #include "xattr.h"
44 #include "acl.h"
45 #include "namei.h"
46 
47 static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
48 			     unsigned long journal_devnum);
49 static int ext4_create_journal(struct super_block *, struct ext4_super_block *,
50 			       unsigned int);
51 static void ext4_commit_super (struct super_block * sb,
52 			       struct ext4_super_block * es,
53 			       int sync);
54 static void ext4_mark_recovery_complete(struct super_block * sb,
55 					struct ext4_super_block * es);
56 static void ext4_clear_journal_err(struct super_block * sb,
57 				   struct ext4_super_block * es);
58 static int ext4_sync_fs(struct super_block *sb, int wait);
59 static const char *ext4_decode_error(struct super_block * sb, int errno,
60 				     char nbuf[16]);
61 static int ext4_remount (struct super_block * sb, int * flags, char * data);
62 static int ext4_statfs (struct dentry * dentry, struct kstatfs * buf);
63 static void ext4_unlockfs(struct super_block *sb);
64 static void ext4_write_super (struct super_block * sb);
65 static void ext4_write_super_lockfs(struct super_block *sb);
66 
67 
68 ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
69 			       struct ext4_group_desc *bg)
70 {
71 	return le32_to_cpu(bg->bg_block_bitmap) |
72 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
73 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_block_bitmap_hi) << 32 : 0);
74 }
75 
76 ext4_fsblk_t ext4_inode_bitmap(struct super_block *sb,
77 			       struct ext4_group_desc *bg)
78 {
79 	return le32_to_cpu(bg->bg_inode_bitmap) |
80 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
81 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_bitmap_hi) << 32 : 0);
82 }
83 
84 ext4_fsblk_t ext4_inode_table(struct super_block *sb,
85 			      struct ext4_group_desc *bg)
86 {
87 	return le32_to_cpu(bg->bg_inode_table) |
88 		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
89 		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_table_hi) << 32 : 0);
90 }
91 
92 void ext4_block_bitmap_set(struct super_block *sb,
93 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
94 {
95 	bg->bg_block_bitmap = cpu_to_le32((u32)blk);
96 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
97 		bg->bg_block_bitmap_hi = cpu_to_le32(blk >> 32);
98 }
99 
100 void ext4_inode_bitmap_set(struct super_block *sb,
101 			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
102 {
103 	bg->bg_inode_bitmap  = cpu_to_le32((u32)blk);
104 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
105 		bg->bg_inode_bitmap_hi = cpu_to_le32(blk >> 32);
106 }
107 
108 void ext4_inode_table_set(struct super_block *sb,
109 			  struct ext4_group_desc *bg, ext4_fsblk_t blk)
110 {
111 	bg->bg_inode_table = cpu_to_le32((u32)blk);
112 	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
113 		bg->bg_inode_table_hi = cpu_to_le32(blk >> 32);
114 }
115 
116 /*
117  * Wrappers for jbd2_journal_start/end.
118  *
119  * The only special thing we need to do here is to make sure that all
120  * journal_end calls result in the superblock being marked dirty, so
121  * that sync() will call the filesystem's write_super callback if
122  * appropriate.
123  */
124 handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
125 {
126 	journal_t *journal;
127 
128 	if (sb->s_flags & MS_RDONLY)
129 		return ERR_PTR(-EROFS);
130 
131 	/* Special case here: if the journal has aborted behind our
132 	 * backs (eg. EIO in the commit thread), then we still need to
133 	 * take the FS itself readonly cleanly. */
134 	journal = EXT4_SB(sb)->s_journal;
135 	if (is_journal_aborted(journal)) {
136 		ext4_abort(sb, __FUNCTION__,
137 			   "Detected aborted journal");
138 		return ERR_PTR(-EROFS);
139 	}
140 
141 	return jbd2_journal_start(journal, nblocks);
142 }
143 
144 /*
145  * The only special thing we need to do here is to make sure that all
146  * jbd2_journal_stop calls result in the superblock being marked dirty, so
147  * that sync() will call the filesystem's write_super callback if
148  * appropriate.
149  */
150 int __ext4_journal_stop(const char *where, handle_t *handle)
151 {
152 	struct super_block *sb;
153 	int err;
154 	int rc;
155 
156 	sb = handle->h_transaction->t_journal->j_private;
157 	err = handle->h_err;
158 	rc = jbd2_journal_stop(handle);
159 
160 	if (!err)
161 		err = rc;
162 	if (err)
163 		__ext4_std_error(sb, where, err);
164 	return err;
165 }
166 
167 void ext4_journal_abort_handle(const char *caller, const char *err_fn,
168 		struct buffer_head *bh, handle_t *handle, int err)
169 {
170 	char nbuf[16];
171 	const char *errstr = ext4_decode_error(NULL, err, nbuf);
172 
173 	if (bh)
174 		BUFFER_TRACE(bh, "abort");
175 
176 	if (!handle->h_err)
177 		handle->h_err = err;
178 
179 	if (is_handle_aborted(handle))
180 		return;
181 
182 	printk(KERN_ERR "%s: aborting transaction: %s in %s\n",
183 	       caller, errstr, err_fn);
184 
185 	jbd2_journal_abort_handle(handle);
186 }
187 
188 /* Deal with the reporting of failure conditions on a filesystem such as
189  * inconsistencies detected or read IO failures.
190  *
191  * On ext2, we can store the error state of the filesystem in the
192  * superblock.  That is not possible on ext4, because we may have other
193  * write ordering constraints on the superblock which prevent us from
194  * writing it out straight away; and given that the journal is about to
195  * be aborted, we can't rely on the current, or future, transactions to
196  * write out the superblock safely.
197  *
198  * We'll just use the jbd2_journal_abort() error code to record an error in
199  * the journal instead.  On recovery, the journal will compain about
200  * that error until we've noted it down and cleared it.
201  */
202 
203 static void ext4_handle_error(struct super_block *sb)
204 {
205 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
206 
207 	EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
208 	es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
209 
210 	if (sb->s_flags & MS_RDONLY)
211 		return;
212 
213 	if (!test_opt (sb, ERRORS_CONT)) {
214 		journal_t *journal = EXT4_SB(sb)->s_journal;
215 
216 		EXT4_SB(sb)->s_mount_opt |= EXT4_MOUNT_ABORT;
217 		if (journal)
218 			jbd2_journal_abort(journal, -EIO);
219 	}
220 	if (test_opt (sb, ERRORS_RO)) {
221 		printk (KERN_CRIT "Remounting filesystem read-only\n");
222 		sb->s_flags |= MS_RDONLY;
223 	}
224 	ext4_commit_super(sb, es, 1);
225 	if (test_opt(sb, ERRORS_PANIC))
226 		panic("EXT4-fs (device %s): panic forced after error\n",
227 			sb->s_id);
228 }
229 
230 void ext4_error (struct super_block * sb, const char * function,
231 		 const char * fmt, ...)
232 {
233 	va_list args;
234 
235 	va_start(args, fmt);
236 	printk(KERN_CRIT "EXT4-fs error (device %s): %s: ",sb->s_id, function);
237 	vprintk(fmt, args);
238 	printk("\n");
239 	va_end(args);
240 
241 	ext4_handle_error(sb);
242 }
243 
244 static const char *ext4_decode_error(struct super_block * sb, int errno,
245 				     char nbuf[16])
246 {
247 	char *errstr = NULL;
248 
249 	switch (errno) {
250 	case -EIO:
251 		errstr = "IO failure";
252 		break;
253 	case -ENOMEM:
254 		errstr = "Out of memory";
255 		break;
256 	case -EROFS:
257 		if (!sb || EXT4_SB(sb)->s_journal->j_flags & JBD2_ABORT)
258 			errstr = "Journal has aborted";
259 		else
260 			errstr = "Readonly filesystem";
261 		break;
262 	default:
263 		/* If the caller passed in an extra buffer for unknown
264 		 * errors, textualise them now.  Else we just return
265 		 * NULL. */
266 		if (nbuf) {
267 			/* Check for truncated error codes... */
268 			if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
269 				errstr = nbuf;
270 		}
271 		break;
272 	}
273 
274 	return errstr;
275 }
276 
277 /* __ext4_std_error decodes expected errors from journaling functions
278  * automatically and invokes the appropriate error response.  */
279 
280 void __ext4_std_error (struct super_block * sb, const char * function,
281 		       int errno)
282 {
283 	char nbuf[16];
284 	const char *errstr;
285 
286 	/* Special case: if the error is EROFS, and we're not already
287 	 * inside a transaction, then there's really no point in logging
288 	 * an error. */
289 	if (errno == -EROFS && journal_current_handle() == NULL &&
290 	    (sb->s_flags & MS_RDONLY))
291 		return;
292 
293 	errstr = ext4_decode_error(sb, errno, nbuf);
294 	printk (KERN_CRIT "EXT4-fs error (device %s) in %s: %s\n",
295 		sb->s_id, function, errstr);
296 
297 	ext4_handle_error(sb);
298 }
299 
300 /*
301  * ext4_abort is a much stronger failure handler than ext4_error.  The
302  * abort function may be used to deal with unrecoverable failures such
303  * as journal IO errors or ENOMEM at a critical moment in log management.
304  *
305  * We unconditionally force the filesystem into an ABORT|READONLY state,
306  * unless the error response on the fs has been set to panic in which
307  * case we take the easy way out and panic immediately.
308  */
309 
310 void ext4_abort (struct super_block * sb, const char * function,
311 		 const char * fmt, ...)
312 {
313 	va_list args;
314 
315 	printk (KERN_CRIT "ext4_abort called.\n");
316 
317 	va_start(args, fmt);
318 	printk(KERN_CRIT "EXT4-fs error (device %s): %s: ",sb->s_id, function);
319 	vprintk(fmt, args);
320 	printk("\n");
321 	va_end(args);
322 
323 	if (test_opt(sb, ERRORS_PANIC))
324 		panic("EXT4-fs panic from previous error\n");
325 
326 	if (sb->s_flags & MS_RDONLY)
327 		return;
328 
329 	printk(KERN_CRIT "Remounting filesystem read-only\n");
330 	EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
331 	sb->s_flags |= MS_RDONLY;
332 	EXT4_SB(sb)->s_mount_opt |= EXT4_MOUNT_ABORT;
333 	jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
334 }
335 
336 void ext4_warning (struct super_block * sb, const char * function,
337 		   const char * fmt, ...)
338 {
339 	va_list args;
340 
341 	va_start(args, fmt);
342 	printk(KERN_WARNING "EXT4-fs warning (device %s): %s: ",
343 	       sb->s_id, function);
344 	vprintk(fmt, args);
345 	printk("\n");
346 	va_end(args);
347 }
348 
349 void ext4_update_dynamic_rev(struct super_block *sb)
350 {
351 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
352 
353 	if (le32_to_cpu(es->s_rev_level) > EXT4_GOOD_OLD_REV)
354 		return;
355 
356 	ext4_warning(sb, __FUNCTION__,
357 		     "updating to rev %d because of new feature flag, "
358 		     "running e2fsck is recommended",
359 		     EXT4_DYNAMIC_REV);
360 
361 	es->s_first_ino = cpu_to_le32(EXT4_GOOD_OLD_FIRST_INO);
362 	es->s_inode_size = cpu_to_le16(EXT4_GOOD_OLD_INODE_SIZE);
363 	es->s_rev_level = cpu_to_le32(EXT4_DYNAMIC_REV);
364 	/* leave es->s_feature_*compat flags alone */
365 	/* es->s_uuid will be set by e2fsck if empty */
366 
367 	/*
368 	 * The rest of the superblock fields should be zero, and if not it
369 	 * means they are likely already in use, so leave them alone.  We
370 	 * can leave it up to e2fsck to clean up any inconsistencies there.
371 	 */
372 }
373 
374 /*
375  * Open the external journal device
376  */
377 static struct block_device *ext4_blkdev_get(dev_t dev)
378 {
379 	struct block_device *bdev;
380 	char b[BDEVNAME_SIZE];
381 
382 	bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
383 	if (IS_ERR(bdev))
384 		goto fail;
385 	return bdev;
386 
387 fail:
388 	printk(KERN_ERR "EXT4: failed to open journal device %s: %ld\n",
389 			__bdevname(dev, b), PTR_ERR(bdev));
390 	return NULL;
391 }
392 
393 /*
394  * Release the journal device
395  */
396 static int ext4_blkdev_put(struct block_device *bdev)
397 {
398 	bd_release(bdev);
399 	return blkdev_put(bdev);
400 }
401 
402 static int ext4_blkdev_remove(struct ext4_sb_info *sbi)
403 {
404 	struct block_device *bdev;
405 	int ret = -ENODEV;
406 
407 	bdev = sbi->journal_bdev;
408 	if (bdev) {
409 		ret = ext4_blkdev_put(bdev);
410 		sbi->journal_bdev = NULL;
411 	}
412 	return ret;
413 }
414 
415 static inline struct inode *orphan_list_entry(struct list_head *l)
416 {
417 	return &list_entry(l, struct ext4_inode_info, i_orphan)->vfs_inode;
418 }
419 
420 static void dump_orphan_list(struct super_block *sb, struct ext4_sb_info *sbi)
421 {
422 	struct list_head *l;
423 
424 	printk(KERN_ERR "sb orphan head is %d\n",
425 	       le32_to_cpu(sbi->s_es->s_last_orphan));
426 
427 	printk(KERN_ERR "sb_info orphan list:\n");
428 	list_for_each(l, &sbi->s_orphan) {
429 		struct inode *inode = orphan_list_entry(l);
430 		printk(KERN_ERR "  "
431 		       "inode %s:%lu at %p: mode %o, nlink %d, next %d\n",
432 		       inode->i_sb->s_id, inode->i_ino, inode,
433 		       inode->i_mode, inode->i_nlink,
434 		       NEXT_ORPHAN(inode));
435 	}
436 }
437 
438 static void ext4_put_super (struct super_block * sb)
439 {
440 	struct ext4_sb_info *sbi = EXT4_SB(sb);
441 	struct ext4_super_block *es = sbi->s_es;
442 	int i;
443 
444 	ext4_ext_release(sb);
445 	ext4_xattr_put_super(sb);
446 	jbd2_journal_destroy(sbi->s_journal);
447 	if (!(sb->s_flags & MS_RDONLY)) {
448 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
449 		es->s_state = cpu_to_le16(sbi->s_mount_state);
450 		BUFFER_TRACE(sbi->s_sbh, "marking dirty");
451 		mark_buffer_dirty(sbi->s_sbh);
452 		ext4_commit_super(sb, es, 1);
453 	}
454 
455 	for (i = 0; i < sbi->s_gdb_count; i++)
456 		brelse(sbi->s_group_desc[i]);
457 	kfree(sbi->s_group_desc);
458 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
459 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
460 	percpu_counter_destroy(&sbi->s_dirs_counter);
461 	brelse(sbi->s_sbh);
462 #ifdef CONFIG_QUOTA
463 	for (i = 0; i < MAXQUOTAS; i++)
464 		kfree(sbi->s_qf_names[i]);
465 #endif
466 
467 	/* Debugging code just in case the in-memory inode orphan list
468 	 * isn't empty.  The on-disk one can be non-empty if we've
469 	 * detected an error and taken the fs readonly, but the
470 	 * in-memory list had better be clean by this point. */
471 	if (!list_empty(&sbi->s_orphan))
472 		dump_orphan_list(sb, sbi);
473 	J_ASSERT(list_empty(&sbi->s_orphan));
474 
475 	invalidate_bdev(sb->s_bdev);
476 	if (sbi->journal_bdev && sbi->journal_bdev != sb->s_bdev) {
477 		/*
478 		 * Invalidate the journal device's buffers.  We don't want them
479 		 * floating about in memory - the physical journal device may
480 		 * hotswapped, and it breaks the `ro-after' testing code.
481 		 */
482 		sync_blockdev(sbi->journal_bdev);
483 		invalidate_bdev(sbi->journal_bdev);
484 		ext4_blkdev_remove(sbi);
485 	}
486 	sb->s_fs_info = NULL;
487 	kfree(sbi);
488 	return;
489 }
490 
491 static struct kmem_cache *ext4_inode_cachep;
492 
493 /*
494  * Called inside transaction, so use GFP_NOFS
495  */
496 static struct inode *ext4_alloc_inode(struct super_block *sb)
497 {
498 	struct ext4_inode_info *ei;
499 
500 	ei = kmem_cache_alloc(ext4_inode_cachep, GFP_NOFS);
501 	if (!ei)
502 		return NULL;
503 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
504 	ei->i_acl = EXT4_ACL_NOT_CACHED;
505 	ei->i_default_acl = EXT4_ACL_NOT_CACHED;
506 #endif
507 	ei->i_block_alloc_info = NULL;
508 	ei->vfs_inode.i_version = 1;
509 	memset(&ei->i_cached_extent, 0, sizeof(struct ext4_ext_cache));
510 	return &ei->vfs_inode;
511 }
512 
513 static void ext4_destroy_inode(struct inode *inode)
514 {
515 	if (!list_empty(&(EXT4_I(inode)->i_orphan))) {
516 		printk("EXT4 Inode %p: orphan list check failed!\n",
517 			EXT4_I(inode));
518 		print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 16, 4,
519 				EXT4_I(inode), sizeof(struct ext4_inode_info),
520 				true);
521 		dump_stack();
522 	}
523 	kmem_cache_free(ext4_inode_cachep, EXT4_I(inode));
524 }
525 
526 static void init_once(struct kmem_cache *cachep, void *foo)
527 {
528 	struct ext4_inode_info *ei = (struct ext4_inode_info *) foo;
529 
530 	INIT_LIST_HEAD(&ei->i_orphan);
531 #ifdef CONFIG_EXT4DEV_FS_XATTR
532 	init_rwsem(&ei->xattr_sem);
533 #endif
534 	mutex_init(&ei->truncate_mutex);
535 	inode_init_once(&ei->vfs_inode);
536 }
537 
538 static int init_inodecache(void)
539 {
540 	ext4_inode_cachep = kmem_cache_create("ext4_inode_cache",
541 					     sizeof(struct ext4_inode_info),
542 					     0, (SLAB_RECLAIM_ACCOUNT|
543 						SLAB_MEM_SPREAD),
544 					     init_once);
545 	if (ext4_inode_cachep == NULL)
546 		return -ENOMEM;
547 	return 0;
548 }
549 
550 static void destroy_inodecache(void)
551 {
552 	kmem_cache_destroy(ext4_inode_cachep);
553 }
554 
555 static void ext4_clear_inode(struct inode *inode)
556 {
557 	struct ext4_block_alloc_info *rsv = EXT4_I(inode)->i_block_alloc_info;
558 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
559 	if (EXT4_I(inode)->i_acl &&
560 			EXT4_I(inode)->i_acl != EXT4_ACL_NOT_CACHED) {
561 		posix_acl_release(EXT4_I(inode)->i_acl);
562 		EXT4_I(inode)->i_acl = EXT4_ACL_NOT_CACHED;
563 	}
564 	if (EXT4_I(inode)->i_default_acl &&
565 			EXT4_I(inode)->i_default_acl != EXT4_ACL_NOT_CACHED) {
566 		posix_acl_release(EXT4_I(inode)->i_default_acl);
567 		EXT4_I(inode)->i_default_acl = EXT4_ACL_NOT_CACHED;
568 	}
569 #endif
570 	ext4_discard_reservation(inode);
571 	EXT4_I(inode)->i_block_alloc_info = NULL;
572 	if (unlikely(rsv))
573 		kfree(rsv);
574 }
575 
576 static inline void ext4_show_quota_options(struct seq_file *seq, struct super_block *sb)
577 {
578 #if defined(CONFIG_QUOTA)
579 	struct ext4_sb_info *sbi = EXT4_SB(sb);
580 
581 	if (sbi->s_jquota_fmt)
582 		seq_printf(seq, ",jqfmt=%s",
583 		(sbi->s_jquota_fmt == QFMT_VFS_OLD) ? "vfsold": "vfsv0");
584 
585 	if (sbi->s_qf_names[USRQUOTA])
586 		seq_printf(seq, ",usrjquota=%s", sbi->s_qf_names[USRQUOTA]);
587 
588 	if (sbi->s_qf_names[GRPQUOTA])
589 		seq_printf(seq, ",grpjquota=%s", sbi->s_qf_names[GRPQUOTA]);
590 
591 	if (sbi->s_mount_opt & EXT4_MOUNT_USRQUOTA)
592 		seq_puts(seq, ",usrquota");
593 
594 	if (sbi->s_mount_opt & EXT4_MOUNT_GRPQUOTA)
595 		seq_puts(seq, ",grpquota");
596 #endif
597 }
598 
599 /*
600  * Show an option if
601  *  - it's set to a non-default value OR
602  *  - if the per-sb default is different from the global default
603  */
604 static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs)
605 {
606 	struct super_block *sb = vfs->mnt_sb;
607 	struct ext4_sb_info *sbi = EXT4_SB(sb);
608 	struct ext4_super_block *es = sbi->s_es;
609 	unsigned long def_mount_opts;
610 
611 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
612 
613 	if (sbi->s_sb_block != 1)
614 		seq_printf(seq, ",sb=%llu", sbi->s_sb_block);
615 	if (test_opt(sb, MINIX_DF))
616 		seq_puts(seq, ",minixdf");
617 	if (test_opt(sb, GRPID))
618 		seq_puts(seq, ",grpid");
619 	if (!test_opt(sb, GRPID) && (def_mount_opts & EXT4_DEFM_BSDGROUPS))
620 		seq_puts(seq, ",nogrpid");
621 	if (sbi->s_resuid != EXT4_DEF_RESUID ||
622 	    le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID) {
623 		seq_printf(seq, ",resuid=%u", sbi->s_resuid);
624 	}
625 	if (sbi->s_resgid != EXT4_DEF_RESGID ||
626 	    le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID) {
627 		seq_printf(seq, ",resgid=%u", sbi->s_resgid);
628 	}
629 	if (test_opt(sb, ERRORS_CONT)) {
630 		int def_errors = le16_to_cpu(es->s_errors);
631 
632 		if (def_errors == EXT4_ERRORS_PANIC ||
633 		    def_errors == EXT4_ERRORS_RO) {
634 			seq_puts(seq, ",errors=continue");
635 		}
636 	}
637 	if (test_opt(sb, ERRORS_RO))
638 		seq_puts(seq, ",errors=remount-ro");
639 	if (test_opt(sb, ERRORS_PANIC))
640 		seq_puts(seq, ",errors=panic");
641 	if (test_opt(sb, NO_UID32))
642 		seq_puts(seq, ",nouid32");
643 	if (test_opt(sb, DEBUG))
644 		seq_puts(seq, ",debug");
645 	if (test_opt(sb, OLDALLOC))
646 		seq_puts(seq, ",oldalloc");
647 #ifdef CONFIG_EXT4_FS_XATTR
648 	if (test_opt(sb, XATTR_USER))
649 		seq_puts(seq, ",user_xattr");
650 	if (!test_opt(sb, XATTR_USER) &&
651 	    (def_mount_opts & EXT4_DEFM_XATTR_USER)) {
652 		seq_puts(seq, ",nouser_xattr");
653 	}
654 #endif
655 #ifdef CONFIG_EXT4_FS_POSIX_ACL
656 	if (test_opt(sb, POSIX_ACL))
657 		seq_puts(seq, ",acl");
658 	if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT4_DEFM_ACL))
659 		seq_puts(seq, ",noacl");
660 #endif
661 	if (!test_opt(sb, RESERVATION))
662 		seq_puts(seq, ",noreservation");
663 	if (sbi->s_commit_interval) {
664 		seq_printf(seq, ",commit=%u",
665 			   (unsigned) (sbi->s_commit_interval / HZ));
666 	}
667 	if (test_opt(sb, BARRIER))
668 		seq_puts(seq, ",barrier=1");
669 	if (test_opt(sb, NOBH))
670 		seq_puts(seq, ",nobh");
671 	if (!test_opt(sb, EXTENTS))
672 		seq_puts(seq, ",noextents");
673 
674 	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
675 		seq_puts(seq, ",data=journal");
676 	else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
677 		seq_puts(seq, ",data=ordered");
678 	else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
679 		seq_puts(seq, ",data=writeback");
680 
681 	ext4_show_quota_options(seq, sb);
682 
683 	return 0;
684 }
685 
686 
687 static struct dentry *ext4_get_dentry(struct super_block *sb, void *vobjp)
688 {
689 	__u32 *objp = vobjp;
690 	unsigned long ino = objp[0];
691 	__u32 generation = objp[1];
692 	struct inode *inode;
693 	struct dentry *result;
694 
695 	if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
696 		return ERR_PTR(-ESTALE);
697 	if (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
698 		return ERR_PTR(-ESTALE);
699 
700 	/* iget isn't really right if the inode is currently unallocated!!
701 	 *
702 	 * ext4_read_inode will return a bad_inode if the inode had been
703 	 * deleted, so we should be safe.
704 	 *
705 	 * Currently we don't know the generation for parent directory, so
706 	 * a generation of 0 means "accept any"
707 	 */
708 	inode = iget(sb, ino);
709 	if (inode == NULL)
710 		return ERR_PTR(-ENOMEM);
711 	if (is_bad_inode(inode) ||
712 	    (generation && inode->i_generation != generation)) {
713 		iput(inode);
714 		return ERR_PTR(-ESTALE);
715 	}
716 	/* now to find a dentry.
717 	 * If possible, get a well-connected one
718 	 */
719 	result = d_alloc_anon(inode);
720 	if (!result) {
721 		iput(inode);
722 		return ERR_PTR(-ENOMEM);
723 	}
724 	return result;
725 }
726 
727 #ifdef CONFIG_QUOTA
728 #define QTYPE2NAME(t) ((t)==USRQUOTA?"user":"group")
729 #define QTYPE2MOPT(on, t) ((t)==USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
730 
731 static int ext4_dquot_initialize(struct inode *inode, int type);
732 static int ext4_dquot_drop(struct inode *inode);
733 static int ext4_write_dquot(struct dquot *dquot);
734 static int ext4_acquire_dquot(struct dquot *dquot);
735 static int ext4_release_dquot(struct dquot *dquot);
736 static int ext4_mark_dquot_dirty(struct dquot *dquot);
737 static int ext4_write_info(struct super_block *sb, int type);
738 static int ext4_quota_on(struct super_block *sb, int type, int format_id, char *path);
739 static int ext4_quota_on_mount(struct super_block *sb, int type);
740 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
741 			       size_t len, loff_t off);
742 static ssize_t ext4_quota_write(struct super_block *sb, int type,
743 				const char *data, size_t len, loff_t off);
744 
745 static struct dquot_operations ext4_quota_operations = {
746 	.initialize	= ext4_dquot_initialize,
747 	.drop		= ext4_dquot_drop,
748 	.alloc_space	= dquot_alloc_space,
749 	.alloc_inode	= dquot_alloc_inode,
750 	.free_space	= dquot_free_space,
751 	.free_inode	= dquot_free_inode,
752 	.transfer	= dquot_transfer,
753 	.write_dquot	= ext4_write_dquot,
754 	.acquire_dquot	= ext4_acquire_dquot,
755 	.release_dquot	= ext4_release_dquot,
756 	.mark_dirty	= ext4_mark_dquot_dirty,
757 	.write_info	= ext4_write_info
758 };
759 
760 static struct quotactl_ops ext4_qctl_operations = {
761 	.quota_on	= ext4_quota_on,
762 	.quota_off	= vfs_quota_off,
763 	.quota_sync	= vfs_quota_sync,
764 	.get_info	= vfs_get_dqinfo,
765 	.set_info	= vfs_set_dqinfo,
766 	.get_dqblk	= vfs_get_dqblk,
767 	.set_dqblk	= vfs_set_dqblk
768 };
769 #endif
770 
771 static const struct super_operations ext4_sops = {
772 	.alloc_inode	= ext4_alloc_inode,
773 	.destroy_inode	= ext4_destroy_inode,
774 	.read_inode	= ext4_read_inode,
775 	.write_inode	= ext4_write_inode,
776 	.dirty_inode	= ext4_dirty_inode,
777 	.delete_inode	= ext4_delete_inode,
778 	.put_super	= ext4_put_super,
779 	.write_super	= ext4_write_super,
780 	.sync_fs	= ext4_sync_fs,
781 	.write_super_lockfs = ext4_write_super_lockfs,
782 	.unlockfs	= ext4_unlockfs,
783 	.statfs		= ext4_statfs,
784 	.remount_fs	= ext4_remount,
785 	.clear_inode	= ext4_clear_inode,
786 	.show_options	= ext4_show_options,
787 #ifdef CONFIG_QUOTA
788 	.quota_read	= ext4_quota_read,
789 	.quota_write	= ext4_quota_write,
790 #endif
791 };
792 
793 static struct export_operations ext4_export_ops = {
794 	.get_parent = ext4_get_parent,
795 	.get_dentry = ext4_get_dentry,
796 };
797 
798 enum {
799 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
800 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
801 	Opt_nouid32, Opt_nocheck, Opt_debug, Opt_oldalloc, Opt_orlov,
802 	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
803 	Opt_reservation, Opt_noreservation, Opt_noload, Opt_nobh, Opt_bh,
804 	Opt_commit, Opt_journal_update, Opt_journal_inum, Opt_journal_dev,
805 	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
806 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
807 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_quota, Opt_noquota,
808 	Opt_ignore, Opt_barrier, Opt_err, Opt_resize, Opt_usrquota,
809 	Opt_grpquota, Opt_extents, Opt_noextents,
810 };
811 
812 static match_table_t tokens = {
813 	{Opt_bsd_df, "bsddf"},
814 	{Opt_minix_df, "minixdf"},
815 	{Opt_grpid, "grpid"},
816 	{Opt_grpid, "bsdgroups"},
817 	{Opt_nogrpid, "nogrpid"},
818 	{Opt_nogrpid, "sysvgroups"},
819 	{Opt_resgid, "resgid=%u"},
820 	{Opt_resuid, "resuid=%u"},
821 	{Opt_sb, "sb=%u"},
822 	{Opt_err_cont, "errors=continue"},
823 	{Opt_err_panic, "errors=panic"},
824 	{Opt_err_ro, "errors=remount-ro"},
825 	{Opt_nouid32, "nouid32"},
826 	{Opt_nocheck, "nocheck"},
827 	{Opt_nocheck, "check=none"},
828 	{Opt_debug, "debug"},
829 	{Opt_oldalloc, "oldalloc"},
830 	{Opt_orlov, "orlov"},
831 	{Opt_user_xattr, "user_xattr"},
832 	{Opt_nouser_xattr, "nouser_xattr"},
833 	{Opt_acl, "acl"},
834 	{Opt_noacl, "noacl"},
835 	{Opt_reservation, "reservation"},
836 	{Opt_noreservation, "noreservation"},
837 	{Opt_noload, "noload"},
838 	{Opt_nobh, "nobh"},
839 	{Opt_bh, "bh"},
840 	{Opt_commit, "commit=%u"},
841 	{Opt_journal_update, "journal=update"},
842 	{Opt_journal_inum, "journal=%u"},
843 	{Opt_journal_dev, "journal_dev=%u"},
844 	{Opt_abort, "abort"},
845 	{Opt_data_journal, "data=journal"},
846 	{Opt_data_ordered, "data=ordered"},
847 	{Opt_data_writeback, "data=writeback"},
848 	{Opt_offusrjquota, "usrjquota="},
849 	{Opt_usrjquota, "usrjquota=%s"},
850 	{Opt_offgrpjquota, "grpjquota="},
851 	{Opt_grpjquota, "grpjquota=%s"},
852 	{Opt_jqfmt_vfsold, "jqfmt=vfsold"},
853 	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
854 	{Opt_grpquota, "grpquota"},
855 	{Opt_noquota, "noquota"},
856 	{Opt_quota, "quota"},
857 	{Opt_usrquota, "usrquota"},
858 	{Opt_barrier, "barrier=%u"},
859 	{Opt_extents, "extents"},
860 	{Opt_noextents, "noextents"},
861 	{Opt_err, NULL},
862 	{Opt_resize, "resize"},
863 };
864 
865 static ext4_fsblk_t get_sb_block(void **data)
866 {
867 	ext4_fsblk_t	sb_block;
868 	char		*options = (char *) *data;
869 
870 	if (!options || strncmp(options, "sb=", 3) != 0)
871 		return 1;	/* Default location */
872 	options += 3;
873 	/*todo: use simple_strtoll with >32bit ext4 */
874 	sb_block = simple_strtoul(options, &options, 0);
875 	if (*options && *options != ',') {
876 		printk("EXT4-fs: Invalid sb specification: %s\n",
877 		       (char *) *data);
878 		return 1;
879 	}
880 	if (*options == ',')
881 		options++;
882 	*data = (void *) options;
883 	return sb_block;
884 }
885 
886 static int parse_options (char *options, struct super_block *sb,
887 			  unsigned int *inum, unsigned long *journal_devnum,
888 			  ext4_fsblk_t *n_blocks_count, int is_remount)
889 {
890 	struct ext4_sb_info *sbi = EXT4_SB(sb);
891 	char * p;
892 	substring_t args[MAX_OPT_ARGS];
893 	int data_opt = 0;
894 	int option;
895 #ifdef CONFIG_QUOTA
896 	int qtype;
897 	char *qname;
898 #endif
899 
900 	if (!options)
901 		return 1;
902 
903 	while ((p = strsep (&options, ",")) != NULL) {
904 		int token;
905 		if (!*p)
906 			continue;
907 
908 		token = match_token(p, tokens, args);
909 		switch (token) {
910 		case Opt_bsd_df:
911 			clear_opt (sbi->s_mount_opt, MINIX_DF);
912 			break;
913 		case Opt_minix_df:
914 			set_opt (sbi->s_mount_opt, MINIX_DF);
915 			break;
916 		case Opt_grpid:
917 			set_opt (sbi->s_mount_opt, GRPID);
918 			break;
919 		case Opt_nogrpid:
920 			clear_opt (sbi->s_mount_opt, GRPID);
921 			break;
922 		case Opt_resuid:
923 			if (match_int(&args[0], &option))
924 				return 0;
925 			sbi->s_resuid = option;
926 			break;
927 		case Opt_resgid:
928 			if (match_int(&args[0], &option))
929 				return 0;
930 			sbi->s_resgid = option;
931 			break;
932 		case Opt_sb:
933 			/* handled by get_sb_block() instead of here */
934 			/* *sb_block = match_int(&args[0]); */
935 			break;
936 		case Opt_err_panic:
937 			clear_opt (sbi->s_mount_opt, ERRORS_CONT);
938 			clear_opt (sbi->s_mount_opt, ERRORS_RO);
939 			set_opt (sbi->s_mount_opt, ERRORS_PANIC);
940 			break;
941 		case Opt_err_ro:
942 			clear_opt (sbi->s_mount_opt, ERRORS_CONT);
943 			clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
944 			set_opt (sbi->s_mount_opt, ERRORS_RO);
945 			break;
946 		case Opt_err_cont:
947 			clear_opt (sbi->s_mount_opt, ERRORS_RO);
948 			clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
949 			set_opt (sbi->s_mount_opt, ERRORS_CONT);
950 			break;
951 		case Opt_nouid32:
952 			set_opt (sbi->s_mount_opt, NO_UID32);
953 			break;
954 		case Opt_nocheck:
955 			clear_opt (sbi->s_mount_opt, CHECK);
956 			break;
957 		case Opt_debug:
958 			set_opt (sbi->s_mount_opt, DEBUG);
959 			break;
960 		case Opt_oldalloc:
961 			set_opt (sbi->s_mount_opt, OLDALLOC);
962 			break;
963 		case Opt_orlov:
964 			clear_opt (sbi->s_mount_opt, OLDALLOC);
965 			break;
966 #ifdef CONFIG_EXT4DEV_FS_XATTR
967 		case Opt_user_xattr:
968 			set_opt (sbi->s_mount_opt, XATTR_USER);
969 			break;
970 		case Opt_nouser_xattr:
971 			clear_opt (sbi->s_mount_opt, XATTR_USER);
972 			break;
973 #else
974 		case Opt_user_xattr:
975 		case Opt_nouser_xattr:
976 			printk("EXT4 (no)user_xattr options not supported\n");
977 			break;
978 #endif
979 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
980 		case Opt_acl:
981 			set_opt(sbi->s_mount_opt, POSIX_ACL);
982 			break;
983 		case Opt_noacl:
984 			clear_opt(sbi->s_mount_opt, POSIX_ACL);
985 			break;
986 #else
987 		case Opt_acl:
988 		case Opt_noacl:
989 			printk("EXT4 (no)acl options not supported\n");
990 			break;
991 #endif
992 		case Opt_reservation:
993 			set_opt(sbi->s_mount_opt, RESERVATION);
994 			break;
995 		case Opt_noreservation:
996 			clear_opt(sbi->s_mount_opt, RESERVATION);
997 			break;
998 		case Opt_journal_update:
999 			/* @@@ FIXME */
1000 			/* Eventually we will want to be able to create
1001 			   a journal file here.  For now, only allow the
1002 			   user to specify an existing inode to be the
1003 			   journal file. */
1004 			if (is_remount) {
1005 				printk(KERN_ERR "EXT4-fs: cannot specify "
1006 				       "journal on remount\n");
1007 				return 0;
1008 			}
1009 			set_opt (sbi->s_mount_opt, UPDATE_JOURNAL);
1010 			break;
1011 		case Opt_journal_inum:
1012 			if (is_remount) {
1013 				printk(KERN_ERR "EXT4-fs: cannot specify "
1014 				       "journal on remount\n");
1015 				return 0;
1016 			}
1017 			if (match_int(&args[0], &option))
1018 				return 0;
1019 			*inum = option;
1020 			break;
1021 		case Opt_journal_dev:
1022 			if (is_remount) {
1023 				printk(KERN_ERR "EXT4-fs: cannot specify "
1024 				       "journal on remount\n");
1025 				return 0;
1026 			}
1027 			if (match_int(&args[0], &option))
1028 				return 0;
1029 			*journal_devnum = option;
1030 			break;
1031 		case Opt_noload:
1032 			set_opt (sbi->s_mount_opt, NOLOAD);
1033 			break;
1034 		case Opt_commit:
1035 			if (match_int(&args[0], &option))
1036 				return 0;
1037 			if (option < 0)
1038 				return 0;
1039 			if (option == 0)
1040 				option = JBD_DEFAULT_MAX_COMMIT_AGE;
1041 			sbi->s_commit_interval = HZ * option;
1042 			break;
1043 		case Opt_data_journal:
1044 			data_opt = EXT4_MOUNT_JOURNAL_DATA;
1045 			goto datacheck;
1046 		case Opt_data_ordered:
1047 			data_opt = EXT4_MOUNT_ORDERED_DATA;
1048 			goto datacheck;
1049 		case Opt_data_writeback:
1050 			data_opt = EXT4_MOUNT_WRITEBACK_DATA;
1051 		datacheck:
1052 			if (is_remount) {
1053 				if ((sbi->s_mount_opt & EXT4_MOUNT_DATA_FLAGS)
1054 						!= data_opt) {
1055 					printk(KERN_ERR
1056 						"EXT4-fs: cannot change data "
1057 						"mode on remount\n");
1058 					return 0;
1059 				}
1060 			} else {
1061 				sbi->s_mount_opt &= ~EXT4_MOUNT_DATA_FLAGS;
1062 				sbi->s_mount_opt |= data_opt;
1063 			}
1064 			break;
1065 #ifdef CONFIG_QUOTA
1066 		case Opt_usrjquota:
1067 			qtype = USRQUOTA;
1068 			goto set_qf_name;
1069 		case Opt_grpjquota:
1070 			qtype = GRPQUOTA;
1071 set_qf_name:
1072 			if (sb_any_quota_enabled(sb)) {
1073 				printk(KERN_ERR
1074 					"EXT4-fs: Cannot change journalled "
1075 					"quota options when quota turned on.\n");
1076 				return 0;
1077 			}
1078 			qname = match_strdup(&args[0]);
1079 			if (!qname) {
1080 				printk(KERN_ERR
1081 					"EXT4-fs: not enough memory for "
1082 					"storing quotafile name.\n");
1083 				return 0;
1084 			}
1085 			if (sbi->s_qf_names[qtype] &&
1086 			    strcmp(sbi->s_qf_names[qtype], qname)) {
1087 				printk(KERN_ERR
1088 					"EXT4-fs: %s quota file already "
1089 					"specified.\n", QTYPE2NAME(qtype));
1090 				kfree(qname);
1091 				return 0;
1092 			}
1093 			sbi->s_qf_names[qtype] = qname;
1094 			if (strchr(sbi->s_qf_names[qtype], '/')) {
1095 				printk(KERN_ERR
1096 					"EXT4-fs: quotafile must be on "
1097 					"filesystem root.\n");
1098 				kfree(sbi->s_qf_names[qtype]);
1099 				sbi->s_qf_names[qtype] = NULL;
1100 				return 0;
1101 			}
1102 			set_opt(sbi->s_mount_opt, QUOTA);
1103 			break;
1104 		case Opt_offusrjquota:
1105 			qtype = USRQUOTA;
1106 			goto clear_qf_name;
1107 		case Opt_offgrpjquota:
1108 			qtype = GRPQUOTA;
1109 clear_qf_name:
1110 			if (sb_any_quota_enabled(sb)) {
1111 				printk(KERN_ERR "EXT4-fs: Cannot change "
1112 					"journalled quota options when "
1113 					"quota turned on.\n");
1114 				return 0;
1115 			}
1116 			/*
1117 			 * The space will be released later when all options
1118 			 * are confirmed to be correct
1119 			 */
1120 			sbi->s_qf_names[qtype] = NULL;
1121 			break;
1122 		case Opt_jqfmt_vfsold:
1123 			sbi->s_jquota_fmt = QFMT_VFS_OLD;
1124 			break;
1125 		case Opt_jqfmt_vfsv0:
1126 			sbi->s_jquota_fmt = QFMT_VFS_V0;
1127 			break;
1128 		case Opt_quota:
1129 		case Opt_usrquota:
1130 			set_opt(sbi->s_mount_opt, QUOTA);
1131 			set_opt(sbi->s_mount_opt, USRQUOTA);
1132 			break;
1133 		case Opt_grpquota:
1134 			set_opt(sbi->s_mount_opt, QUOTA);
1135 			set_opt(sbi->s_mount_opt, GRPQUOTA);
1136 			break;
1137 		case Opt_noquota:
1138 			if (sb_any_quota_enabled(sb)) {
1139 				printk(KERN_ERR "EXT4-fs: Cannot change quota "
1140 					"options when quota turned on.\n");
1141 				return 0;
1142 			}
1143 			clear_opt(sbi->s_mount_opt, QUOTA);
1144 			clear_opt(sbi->s_mount_opt, USRQUOTA);
1145 			clear_opt(sbi->s_mount_opt, GRPQUOTA);
1146 			break;
1147 #else
1148 		case Opt_quota:
1149 		case Opt_usrquota:
1150 		case Opt_grpquota:
1151 		case Opt_usrjquota:
1152 		case Opt_grpjquota:
1153 		case Opt_offusrjquota:
1154 		case Opt_offgrpjquota:
1155 		case Opt_jqfmt_vfsold:
1156 		case Opt_jqfmt_vfsv0:
1157 			printk(KERN_ERR
1158 				"EXT4-fs: journalled quota options not "
1159 				"supported.\n");
1160 			break;
1161 		case Opt_noquota:
1162 			break;
1163 #endif
1164 		case Opt_abort:
1165 			set_opt(sbi->s_mount_opt, ABORT);
1166 			break;
1167 		case Opt_barrier:
1168 			if (match_int(&args[0], &option))
1169 				return 0;
1170 			if (option)
1171 				set_opt(sbi->s_mount_opt, BARRIER);
1172 			else
1173 				clear_opt(sbi->s_mount_opt, BARRIER);
1174 			break;
1175 		case Opt_ignore:
1176 			break;
1177 		case Opt_resize:
1178 			if (!is_remount) {
1179 				printk("EXT4-fs: resize option only available "
1180 					"for remount\n");
1181 				return 0;
1182 			}
1183 			if (match_int(&args[0], &option) != 0)
1184 				return 0;
1185 			*n_blocks_count = option;
1186 			break;
1187 		case Opt_nobh:
1188 			set_opt(sbi->s_mount_opt, NOBH);
1189 			break;
1190 		case Opt_bh:
1191 			clear_opt(sbi->s_mount_opt, NOBH);
1192 			break;
1193 		case Opt_extents:
1194 			set_opt (sbi->s_mount_opt, EXTENTS);
1195 			break;
1196 		case Opt_noextents:
1197 			clear_opt (sbi->s_mount_opt, EXTENTS);
1198 			break;
1199 		default:
1200 			printk (KERN_ERR
1201 				"EXT4-fs: Unrecognized mount option \"%s\" "
1202 				"or missing value\n", p);
1203 			return 0;
1204 		}
1205 	}
1206 #ifdef CONFIG_QUOTA
1207 	if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
1208 		if ((sbi->s_mount_opt & EXT4_MOUNT_USRQUOTA) &&
1209 		     sbi->s_qf_names[USRQUOTA])
1210 			clear_opt(sbi->s_mount_opt, USRQUOTA);
1211 
1212 		if ((sbi->s_mount_opt & EXT4_MOUNT_GRPQUOTA) &&
1213 		     sbi->s_qf_names[GRPQUOTA])
1214 			clear_opt(sbi->s_mount_opt, GRPQUOTA);
1215 
1216 		if ((sbi->s_qf_names[USRQUOTA] &&
1217 				(sbi->s_mount_opt & EXT4_MOUNT_GRPQUOTA)) ||
1218 		    (sbi->s_qf_names[GRPQUOTA] &&
1219 				(sbi->s_mount_opt & EXT4_MOUNT_USRQUOTA))) {
1220 			printk(KERN_ERR "EXT4-fs: old and new quota "
1221 					"format mixing.\n");
1222 			return 0;
1223 		}
1224 
1225 		if (!sbi->s_jquota_fmt) {
1226 			printk(KERN_ERR "EXT4-fs: journalled quota format "
1227 					"not specified.\n");
1228 			return 0;
1229 		}
1230 	} else {
1231 		if (sbi->s_jquota_fmt) {
1232 			printk(KERN_ERR "EXT4-fs: journalled quota format "
1233 					"specified with no journalling "
1234 					"enabled.\n");
1235 			return 0;
1236 		}
1237 	}
1238 #endif
1239 	return 1;
1240 }
1241 
1242 static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
1243 			    int read_only)
1244 {
1245 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1246 	int res = 0;
1247 
1248 	if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
1249 		printk (KERN_ERR "EXT4-fs warning: revision level too high, "
1250 			"forcing read-only mode\n");
1251 		res = MS_RDONLY;
1252 	}
1253 	if (read_only)
1254 		return res;
1255 	if (!(sbi->s_mount_state & EXT4_VALID_FS))
1256 		printk (KERN_WARNING "EXT4-fs warning: mounting unchecked fs, "
1257 			"running e2fsck is recommended\n");
1258 	else if ((sbi->s_mount_state & EXT4_ERROR_FS))
1259 		printk (KERN_WARNING
1260 			"EXT4-fs warning: mounting fs with errors, "
1261 			"running e2fsck is recommended\n");
1262 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
1263 		 le16_to_cpu(es->s_mnt_count) >=
1264 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
1265 		printk (KERN_WARNING
1266 			"EXT4-fs warning: maximal mount count reached, "
1267 			"running e2fsck is recommended\n");
1268 	else if (le32_to_cpu(es->s_checkinterval) &&
1269 		(le32_to_cpu(es->s_lastcheck) +
1270 			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
1271 		printk (KERN_WARNING
1272 			"EXT4-fs warning: checktime reached, "
1273 			"running e2fsck is recommended\n");
1274 #if 0
1275 		/* @@@ We _will_ want to clear the valid bit if we find
1276 		 * inconsistencies, to force a fsck at reboot.  But for
1277 		 * a plain journaled filesystem we can keep it set as
1278 		 * valid forever! :)
1279 		 */
1280 	es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) & ~EXT4_VALID_FS);
1281 #endif
1282 	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
1283 		es->s_max_mnt_count = cpu_to_le16(EXT4_DFL_MAX_MNT_COUNT);
1284 	es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
1285 	es->s_mtime = cpu_to_le32(get_seconds());
1286 	ext4_update_dynamic_rev(sb);
1287 	EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
1288 
1289 	ext4_commit_super(sb, es, 1);
1290 	if (test_opt(sb, DEBUG))
1291 		printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%lu, "
1292 				"bpg=%lu, ipg=%lu, mo=%04lx]\n",
1293 			sb->s_blocksize,
1294 			sbi->s_groups_count,
1295 			EXT4_BLOCKS_PER_GROUP(sb),
1296 			EXT4_INODES_PER_GROUP(sb),
1297 			sbi->s_mount_opt);
1298 
1299 	printk(KERN_INFO "EXT4 FS on %s, ", sb->s_id);
1300 	if (EXT4_SB(sb)->s_journal->j_inode == NULL) {
1301 		char b[BDEVNAME_SIZE];
1302 
1303 		printk("external journal on %s\n",
1304 			bdevname(EXT4_SB(sb)->s_journal->j_dev, b));
1305 	} else {
1306 		printk("internal journal\n");
1307 	}
1308 	return res;
1309 }
1310 
1311 /* Called at mount-time, super-block is locked */
1312 static int ext4_check_descriptors (struct super_block * sb)
1313 {
1314 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1315 	ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
1316 	ext4_fsblk_t last_block;
1317 	ext4_fsblk_t block_bitmap;
1318 	ext4_fsblk_t inode_bitmap;
1319 	ext4_fsblk_t inode_table;
1320 	struct ext4_group_desc * gdp = NULL;
1321 	int desc_block = 0;
1322 	int i;
1323 
1324 	ext4_debug ("Checking group descriptors");
1325 
1326 	for (i = 0; i < sbi->s_groups_count; i++)
1327 	{
1328 		if (i == sbi->s_groups_count - 1)
1329 			last_block = ext4_blocks_count(sbi->s_es) - 1;
1330 		else
1331 			last_block = first_block +
1332 				(EXT4_BLOCKS_PER_GROUP(sb) - 1);
1333 
1334 		if ((i % EXT4_DESC_PER_BLOCK(sb)) == 0)
1335 			gdp = (struct ext4_group_desc *)
1336 					sbi->s_group_desc[desc_block++]->b_data;
1337 		block_bitmap = ext4_block_bitmap(sb, gdp);
1338 		if (block_bitmap < first_block || block_bitmap > last_block)
1339 		{
1340 			ext4_error (sb, "ext4_check_descriptors",
1341 				    "Block bitmap for group %d"
1342 				    " not in group (block %llu)!",
1343 				    i, block_bitmap);
1344 			return 0;
1345 		}
1346 		inode_bitmap = ext4_inode_bitmap(sb, gdp);
1347 		if (inode_bitmap < first_block || inode_bitmap > last_block)
1348 		{
1349 			ext4_error (sb, "ext4_check_descriptors",
1350 				    "Inode bitmap for group %d"
1351 				    " not in group (block %llu)!",
1352 				    i, inode_bitmap);
1353 			return 0;
1354 		}
1355 		inode_table = ext4_inode_table(sb, gdp);
1356 		if (inode_table < first_block ||
1357 		    inode_table + sbi->s_itb_per_group - 1 > last_block)
1358 		{
1359 			ext4_error (sb, "ext4_check_descriptors",
1360 				    "Inode table for group %d"
1361 				    " not in group (block %llu)!",
1362 				    i, inode_table);
1363 			return 0;
1364 		}
1365 		first_block += EXT4_BLOCKS_PER_GROUP(sb);
1366 		gdp = (struct ext4_group_desc *)
1367 			((__u8 *)gdp + EXT4_DESC_SIZE(sb));
1368 	}
1369 
1370 	ext4_free_blocks_count_set(sbi->s_es, ext4_count_free_blocks(sb));
1371 	sbi->s_es->s_free_inodes_count=cpu_to_le32(ext4_count_free_inodes(sb));
1372 	return 1;
1373 }
1374 
1375 
1376 /* ext4_orphan_cleanup() walks a singly-linked list of inodes (starting at
1377  * the superblock) which were deleted from all directories, but held open by
1378  * a process at the time of a crash.  We walk the list and try to delete these
1379  * inodes at recovery time (only with a read-write filesystem).
1380  *
1381  * In order to keep the orphan inode chain consistent during traversal (in
1382  * case of crash during recovery), we link each inode into the superblock
1383  * orphan list_head and handle it the same way as an inode deletion during
1384  * normal operation (which journals the operations for us).
1385  *
1386  * We only do an iget() and an iput() on each inode, which is very safe if we
1387  * accidentally point at an in-use or already deleted inode.  The worst that
1388  * can happen in this case is that we get a "bit already cleared" message from
1389  * ext4_free_inode().  The only reason we would point at a wrong inode is if
1390  * e2fsck was run on this filesystem, and it must have already done the orphan
1391  * inode cleanup for us, so we can safely abort without any further action.
1392  */
1393 static void ext4_orphan_cleanup (struct super_block * sb,
1394 				 struct ext4_super_block * es)
1395 {
1396 	unsigned int s_flags = sb->s_flags;
1397 	int nr_orphans = 0, nr_truncates = 0;
1398 #ifdef CONFIG_QUOTA
1399 	int i;
1400 #endif
1401 	if (!es->s_last_orphan) {
1402 		jbd_debug(4, "no orphan inodes to clean up\n");
1403 		return;
1404 	}
1405 
1406 	if (bdev_read_only(sb->s_bdev)) {
1407 		printk(KERN_ERR "EXT4-fs: write access "
1408 			"unavailable, skipping orphan cleanup.\n");
1409 		return;
1410 	}
1411 
1412 	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
1413 		if (es->s_last_orphan)
1414 			jbd_debug(1, "Errors on filesystem, "
1415 				  "clearing orphan list.\n");
1416 		es->s_last_orphan = 0;
1417 		jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
1418 		return;
1419 	}
1420 
1421 	if (s_flags & MS_RDONLY) {
1422 		printk(KERN_INFO "EXT4-fs: %s: orphan cleanup on readonly fs\n",
1423 		       sb->s_id);
1424 		sb->s_flags &= ~MS_RDONLY;
1425 	}
1426 #ifdef CONFIG_QUOTA
1427 	/* Needed for iput() to work correctly and not trash data */
1428 	sb->s_flags |= MS_ACTIVE;
1429 	/* Turn on quotas so that they are updated correctly */
1430 	for (i = 0; i < MAXQUOTAS; i++) {
1431 		if (EXT4_SB(sb)->s_qf_names[i]) {
1432 			int ret = ext4_quota_on_mount(sb, i);
1433 			if (ret < 0)
1434 				printk(KERN_ERR
1435 					"EXT4-fs: Cannot turn on journalled "
1436 					"quota: error %d\n", ret);
1437 		}
1438 	}
1439 #endif
1440 
1441 	while (es->s_last_orphan) {
1442 		struct inode *inode;
1443 
1444 		if (!(inode =
1445 		      ext4_orphan_get(sb, le32_to_cpu(es->s_last_orphan)))) {
1446 			es->s_last_orphan = 0;
1447 			break;
1448 		}
1449 
1450 		list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
1451 		DQUOT_INIT(inode);
1452 		if (inode->i_nlink) {
1453 			printk(KERN_DEBUG
1454 				"%s: truncating inode %lu to %Ld bytes\n",
1455 				__FUNCTION__, inode->i_ino, inode->i_size);
1456 			jbd_debug(2, "truncating inode %lu to %Ld bytes\n",
1457 				  inode->i_ino, inode->i_size);
1458 			ext4_truncate(inode);
1459 			nr_truncates++;
1460 		} else {
1461 			printk(KERN_DEBUG
1462 				"%s: deleting unreferenced inode %lu\n",
1463 				__FUNCTION__, inode->i_ino);
1464 			jbd_debug(2, "deleting unreferenced inode %lu\n",
1465 				  inode->i_ino);
1466 			nr_orphans++;
1467 		}
1468 		iput(inode);  /* The delete magic happens here! */
1469 	}
1470 
1471 #define PLURAL(x) (x), ((x)==1) ? "" : "s"
1472 
1473 	if (nr_orphans)
1474 		printk(KERN_INFO "EXT4-fs: %s: %d orphan inode%s deleted\n",
1475 		       sb->s_id, PLURAL(nr_orphans));
1476 	if (nr_truncates)
1477 		printk(KERN_INFO "EXT4-fs: %s: %d truncate%s cleaned up\n",
1478 		       sb->s_id, PLURAL(nr_truncates));
1479 #ifdef CONFIG_QUOTA
1480 	/* Turn quotas off */
1481 	for (i = 0; i < MAXQUOTAS; i++) {
1482 		if (sb_dqopt(sb)->files[i])
1483 			vfs_quota_off(sb, i);
1484 	}
1485 #endif
1486 	sb->s_flags = s_flags; /* Restore MS_RDONLY status */
1487 }
1488 
1489 /*
1490  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
1491  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
1492  * We need to be 1 filesystem block less than the 2^32 sector limit.
1493  */
1494 static loff_t ext4_max_size(int bits)
1495 {
1496 	loff_t res = EXT4_NDIR_BLOCKS;
1497 	/* This constant is calculated to be the largest file size for a
1498 	 * dense, 4k-blocksize file such that the total number of
1499 	 * sectors in the file, including data and all indirect blocks,
1500 	 * does not exceed 2^32. */
1501 	const loff_t upper_limit = 0x1ff7fffd000LL;
1502 
1503 	res += 1LL << (bits-2);
1504 	res += 1LL << (2*(bits-2));
1505 	res += 1LL << (3*(bits-2));
1506 	res <<= bits;
1507 	if (res > upper_limit)
1508 		res = upper_limit;
1509 	return res;
1510 }
1511 
1512 static ext4_fsblk_t descriptor_loc(struct super_block *sb,
1513 				ext4_fsblk_t logical_sb_block, int nr)
1514 {
1515 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1516 	unsigned long bg, first_meta_bg;
1517 	int has_super = 0;
1518 
1519 	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
1520 
1521 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
1522 	    nr < first_meta_bg)
1523 		return logical_sb_block + nr + 1;
1524 	bg = sbi->s_desc_per_block * nr;
1525 	if (ext4_bg_has_super(sb, bg))
1526 		has_super = 1;
1527 	return (has_super + ext4_group_first_block_no(sb, bg));
1528 }
1529 
1530 
1531 static int ext4_fill_super (struct super_block *sb, void *data, int silent)
1532 {
1533 	struct buffer_head * bh;
1534 	struct ext4_super_block *es = NULL;
1535 	struct ext4_sb_info *sbi;
1536 	ext4_fsblk_t block;
1537 	ext4_fsblk_t sb_block = get_sb_block(&data);
1538 	ext4_fsblk_t logical_sb_block;
1539 	unsigned long offset = 0;
1540 	unsigned int journal_inum = 0;
1541 	unsigned long journal_devnum = 0;
1542 	unsigned long def_mount_opts;
1543 	struct inode *root;
1544 	int blocksize;
1545 	int hblock;
1546 	int db_count;
1547 	int i;
1548 	int needs_recovery;
1549 	__le32 features;
1550 	__u64 blocks_count;
1551 	int err;
1552 
1553 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
1554 	if (!sbi)
1555 		return -ENOMEM;
1556 	sb->s_fs_info = sbi;
1557 	sbi->s_mount_opt = 0;
1558 	sbi->s_resuid = EXT4_DEF_RESUID;
1559 	sbi->s_resgid = EXT4_DEF_RESGID;
1560 	sbi->s_sb_block = sb_block;
1561 
1562 	unlock_kernel();
1563 
1564 	blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
1565 	if (!blocksize) {
1566 		printk(KERN_ERR "EXT4-fs: unable to set blocksize\n");
1567 		goto out_fail;
1568 	}
1569 
1570 	/*
1571 	 * The ext4 superblock will not be buffer aligned for other than 1kB
1572 	 * block sizes.  We need to calculate the offset from buffer start.
1573 	 */
1574 	if (blocksize != EXT4_MIN_BLOCK_SIZE) {
1575 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
1576 		offset = do_div(logical_sb_block, blocksize);
1577 	} else {
1578 		logical_sb_block = sb_block;
1579 	}
1580 
1581 	if (!(bh = sb_bread(sb, logical_sb_block))) {
1582 		printk (KERN_ERR "EXT4-fs: unable to read superblock\n");
1583 		goto out_fail;
1584 	}
1585 	/*
1586 	 * Note: s_es must be initialized as soon as possible because
1587 	 *       some ext4 macro-instructions depend on its value
1588 	 */
1589 	es = (struct ext4_super_block *) (((char *)bh->b_data) + offset);
1590 	sbi->s_es = es;
1591 	sb->s_magic = le16_to_cpu(es->s_magic);
1592 	if (sb->s_magic != EXT4_SUPER_MAGIC)
1593 		goto cantfind_ext4;
1594 
1595 	/* Set defaults before we parse the mount options */
1596 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
1597 	if (def_mount_opts & EXT4_DEFM_DEBUG)
1598 		set_opt(sbi->s_mount_opt, DEBUG);
1599 	if (def_mount_opts & EXT4_DEFM_BSDGROUPS)
1600 		set_opt(sbi->s_mount_opt, GRPID);
1601 	if (def_mount_opts & EXT4_DEFM_UID16)
1602 		set_opt(sbi->s_mount_opt, NO_UID32);
1603 #ifdef CONFIG_EXT4DEV_FS_XATTR
1604 	if (def_mount_opts & EXT4_DEFM_XATTR_USER)
1605 		set_opt(sbi->s_mount_opt, XATTR_USER);
1606 #endif
1607 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
1608 	if (def_mount_opts & EXT4_DEFM_ACL)
1609 		set_opt(sbi->s_mount_opt, POSIX_ACL);
1610 #endif
1611 	if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA)
1612 		sbi->s_mount_opt |= EXT4_MOUNT_JOURNAL_DATA;
1613 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_ORDERED)
1614 		sbi->s_mount_opt |= EXT4_MOUNT_ORDERED_DATA;
1615 	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_WBACK)
1616 		sbi->s_mount_opt |= EXT4_MOUNT_WRITEBACK_DATA;
1617 
1618 	if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_PANIC)
1619 		set_opt(sbi->s_mount_opt, ERRORS_PANIC);
1620 	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_RO)
1621 		set_opt(sbi->s_mount_opt, ERRORS_RO);
1622 	else
1623 		set_opt(sbi->s_mount_opt, ERRORS_CONT);
1624 
1625 	sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
1626 	sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
1627 
1628 	set_opt(sbi->s_mount_opt, RESERVATION);
1629 
1630 	/*
1631 	 * turn on extents feature by default in ext4 filesystem
1632 	 * User -o noextents to turn it off
1633 	 */
1634 	set_opt(sbi->s_mount_opt, EXTENTS);
1635 
1636 	if (!parse_options ((char *) data, sb, &journal_inum, &journal_devnum,
1637 			    NULL, 0))
1638 		goto failed_mount;
1639 
1640 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1641 		((sbi->s_mount_opt & EXT4_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1642 
1643 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
1644 	    (EXT4_HAS_COMPAT_FEATURE(sb, ~0U) ||
1645 	     EXT4_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
1646 	     EXT4_HAS_INCOMPAT_FEATURE(sb, ~0U)))
1647 		printk(KERN_WARNING
1648 		       "EXT4-fs warning: feature flags set on rev 0 fs, "
1649 		       "running e2fsck is recommended\n");
1650 	/*
1651 	 * Check feature flags regardless of the revision level, since we
1652 	 * previously didn't change the revision level when setting the flags,
1653 	 * so there is a chance incompat flags are set on a rev 0 filesystem.
1654 	 */
1655 	features = EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT4_FEATURE_INCOMPAT_SUPP);
1656 	if (features) {
1657 		printk(KERN_ERR "EXT4-fs: %s: couldn't mount because of "
1658 		       "unsupported optional features (%x).\n",
1659 		       sb->s_id, le32_to_cpu(features));
1660 		goto failed_mount;
1661 	}
1662 	features = EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT4_FEATURE_RO_COMPAT_SUPP);
1663 	if (!(sb->s_flags & MS_RDONLY) && features) {
1664 		printk(KERN_ERR "EXT4-fs: %s: couldn't mount RDWR because of "
1665 		       "unsupported optional features (%x).\n",
1666 		       sb->s_id, le32_to_cpu(features));
1667 		goto failed_mount;
1668 	}
1669 	blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
1670 
1671 	if (blocksize < EXT4_MIN_BLOCK_SIZE ||
1672 	    blocksize > EXT4_MAX_BLOCK_SIZE) {
1673 		printk(KERN_ERR
1674 		       "EXT4-fs: Unsupported filesystem blocksize %d on %s.\n",
1675 		       blocksize, sb->s_id);
1676 		goto failed_mount;
1677 	}
1678 
1679 	hblock = bdev_hardsect_size(sb->s_bdev);
1680 	if (sb->s_blocksize != blocksize) {
1681 		/*
1682 		 * Make sure the blocksize for the filesystem is larger
1683 		 * than the hardware sectorsize for the machine.
1684 		 */
1685 		if (blocksize < hblock) {
1686 			printk(KERN_ERR "EXT4-fs: blocksize %d too small for "
1687 			       "device blocksize %d.\n", blocksize, hblock);
1688 			goto failed_mount;
1689 		}
1690 
1691 		brelse (bh);
1692 		sb_set_blocksize(sb, blocksize);
1693 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
1694 		offset = do_div(logical_sb_block, blocksize);
1695 		bh = sb_bread(sb, logical_sb_block);
1696 		if (!bh) {
1697 			printk(KERN_ERR
1698 			       "EXT4-fs: Can't read superblock on 2nd try.\n");
1699 			goto failed_mount;
1700 		}
1701 		es = (struct ext4_super_block *)(((char *)bh->b_data) + offset);
1702 		sbi->s_es = es;
1703 		if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
1704 			printk (KERN_ERR
1705 				"EXT4-fs: Magic mismatch, very weird !\n");
1706 			goto failed_mount;
1707 		}
1708 	}
1709 
1710 	sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits);
1711 
1712 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) {
1713 		sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE;
1714 		sbi->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
1715 	} else {
1716 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
1717 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
1718 		if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
1719 		    (!is_power_of_2(sbi->s_inode_size)) ||
1720 		    (sbi->s_inode_size > blocksize)) {
1721 			printk (KERN_ERR
1722 				"EXT4-fs: unsupported inode size: %d\n",
1723 				sbi->s_inode_size);
1724 			goto failed_mount;
1725 		}
1726 		if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE)
1727 			sb->s_time_gran = 1 << (EXT4_EPOCH_BITS - 2);
1728 	}
1729 	sbi->s_frag_size = EXT4_MIN_FRAG_SIZE <<
1730 				   le32_to_cpu(es->s_log_frag_size);
1731 	if (blocksize != sbi->s_frag_size) {
1732 		printk(KERN_ERR
1733 		       "EXT4-fs: fragsize %lu != blocksize %u (unsupported)\n",
1734 		       sbi->s_frag_size, blocksize);
1735 		goto failed_mount;
1736 	}
1737 	sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
1738 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT)) {
1739 		if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT ||
1740 		    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
1741 		    !is_power_of_2(sbi->s_desc_size)) {
1742 			printk(KERN_ERR
1743 			       "EXT4-fs: unsupported descriptor size %lu\n",
1744 			       sbi->s_desc_size);
1745 			goto failed_mount;
1746 		}
1747 	} else
1748 		sbi->s_desc_size = EXT4_MIN_DESC_SIZE;
1749 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
1750 	sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
1751 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
1752 	if (EXT4_INODE_SIZE(sb) == 0)
1753 		goto cantfind_ext4;
1754 	sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
1755 	if (sbi->s_inodes_per_block == 0)
1756 		goto cantfind_ext4;
1757 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
1758 					sbi->s_inodes_per_block;
1759 	sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
1760 	sbi->s_sbh = bh;
1761 	sbi->s_mount_state = le16_to_cpu(es->s_state);
1762 	sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
1763 	sbi->s_desc_per_block_bits = ilog2(EXT4_DESC_PER_BLOCK(sb));
1764 	for (i=0; i < 4; i++)
1765 		sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
1766 	sbi->s_def_hash_version = es->s_def_hash_version;
1767 
1768 	if (sbi->s_blocks_per_group > blocksize * 8) {
1769 		printk (KERN_ERR
1770 			"EXT4-fs: #blocks per group too big: %lu\n",
1771 			sbi->s_blocks_per_group);
1772 		goto failed_mount;
1773 	}
1774 	if (sbi->s_frags_per_group > blocksize * 8) {
1775 		printk (KERN_ERR
1776 			"EXT4-fs: #fragments per group too big: %lu\n",
1777 			sbi->s_frags_per_group);
1778 		goto failed_mount;
1779 	}
1780 	if (sbi->s_inodes_per_group > blocksize * 8) {
1781 		printk (KERN_ERR
1782 			"EXT4-fs: #inodes per group too big: %lu\n",
1783 			sbi->s_inodes_per_group);
1784 		goto failed_mount;
1785 	}
1786 
1787 	if (ext4_blocks_count(es) >
1788 		    (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1789 		printk(KERN_ERR "EXT4-fs: filesystem on %s:"
1790 			" too large to mount safely\n", sb->s_id);
1791 		if (sizeof(sector_t) < 8)
1792 			printk(KERN_WARNING "EXT4-fs: CONFIG_LBD not "
1793 					"enabled\n");
1794 		goto failed_mount;
1795 	}
1796 
1797 	if (EXT4_BLOCKS_PER_GROUP(sb) == 0)
1798 		goto cantfind_ext4;
1799 	blocks_count = (ext4_blocks_count(es) -
1800 			le32_to_cpu(es->s_first_data_block) +
1801 			EXT4_BLOCKS_PER_GROUP(sb) - 1);
1802 	do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
1803 	sbi->s_groups_count = blocks_count;
1804 	db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
1805 		   EXT4_DESC_PER_BLOCK(sb);
1806 	sbi->s_group_desc = kmalloc(db_count * sizeof (struct buffer_head *),
1807 				    GFP_KERNEL);
1808 	if (sbi->s_group_desc == NULL) {
1809 		printk (KERN_ERR "EXT4-fs: not enough memory\n");
1810 		goto failed_mount;
1811 	}
1812 
1813 	bgl_lock_init(&sbi->s_blockgroup_lock);
1814 
1815 	for (i = 0; i < db_count; i++) {
1816 		block = descriptor_loc(sb, logical_sb_block, i);
1817 		sbi->s_group_desc[i] = sb_bread(sb, block);
1818 		if (!sbi->s_group_desc[i]) {
1819 			printk (KERN_ERR "EXT4-fs: "
1820 				"can't read group descriptor %d\n", i);
1821 			db_count = i;
1822 			goto failed_mount2;
1823 		}
1824 	}
1825 	if (!ext4_check_descriptors (sb)) {
1826 		printk(KERN_ERR "EXT4-fs: group descriptors corrupted!\n");
1827 		goto failed_mount2;
1828 	}
1829 	sbi->s_gdb_count = db_count;
1830 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1831 	spin_lock_init(&sbi->s_next_gen_lock);
1832 
1833 	err = percpu_counter_init(&sbi->s_freeblocks_counter,
1834 			ext4_count_free_blocks(sb));
1835 	if (!err) {
1836 		err = percpu_counter_init(&sbi->s_freeinodes_counter,
1837 				ext4_count_free_inodes(sb));
1838 	}
1839 	if (!err) {
1840 		err = percpu_counter_init(&sbi->s_dirs_counter,
1841 				ext4_count_dirs(sb));
1842 	}
1843 	if (err) {
1844 		printk(KERN_ERR "EXT4-fs: insufficient memory\n");
1845 		goto failed_mount3;
1846 	}
1847 
1848 	/* per fileystem reservation list head & lock */
1849 	spin_lock_init(&sbi->s_rsv_window_lock);
1850 	sbi->s_rsv_window_root = RB_ROOT;
1851 	/* Add a single, static dummy reservation to the start of the
1852 	 * reservation window list --- it gives us a placeholder for
1853 	 * append-at-start-of-list which makes the allocation logic
1854 	 * _much_ simpler. */
1855 	sbi->s_rsv_window_head.rsv_start = EXT4_RESERVE_WINDOW_NOT_ALLOCATED;
1856 	sbi->s_rsv_window_head.rsv_end = EXT4_RESERVE_WINDOW_NOT_ALLOCATED;
1857 	sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1858 	sbi->s_rsv_window_head.rsv_goal_size = 0;
1859 	ext4_rsv_window_add(sb, &sbi->s_rsv_window_head);
1860 
1861 	/*
1862 	 * set up enough so that it can read an inode
1863 	 */
1864 	sb->s_op = &ext4_sops;
1865 	sb->s_export_op = &ext4_export_ops;
1866 	sb->s_xattr = ext4_xattr_handlers;
1867 #ifdef CONFIG_QUOTA
1868 	sb->s_qcop = &ext4_qctl_operations;
1869 	sb->dq_op = &ext4_quota_operations;
1870 #endif
1871 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
1872 
1873 	sb->s_root = NULL;
1874 
1875 	needs_recovery = (es->s_last_orphan != 0 ||
1876 			  EXT4_HAS_INCOMPAT_FEATURE(sb,
1877 				    EXT4_FEATURE_INCOMPAT_RECOVER));
1878 
1879 	/*
1880 	 * The first inode we look at is the journal inode.  Don't try
1881 	 * root first: it may be modified in the journal!
1882 	 */
1883 	if (!test_opt(sb, NOLOAD) &&
1884 	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
1885 		if (ext4_load_journal(sb, es, journal_devnum))
1886 			goto failed_mount3;
1887 	} else if (journal_inum) {
1888 		if (ext4_create_journal(sb, es, journal_inum))
1889 			goto failed_mount3;
1890 	} else {
1891 		if (!silent)
1892 			printk (KERN_ERR
1893 				"ext4: No journal on filesystem on %s\n",
1894 				sb->s_id);
1895 		goto failed_mount3;
1896 	}
1897 
1898 	if (ext4_blocks_count(es) > 0xffffffffULL &&
1899 	    !jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
1900 				       JBD2_FEATURE_INCOMPAT_64BIT)) {
1901 		printk(KERN_ERR "ext4: Failed to set 64-bit journal feature\n");
1902 		goto failed_mount4;
1903 	}
1904 
1905 	/* We have now updated the journal if required, so we can
1906 	 * validate the data journaling mode. */
1907 	switch (test_opt(sb, DATA_FLAGS)) {
1908 	case 0:
1909 		/* No mode set, assume a default based on the journal
1910 		 * capabilities: ORDERED_DATA if the journal can
1911 		 * cope, else JOURNAL_DATA
1912 		 */
1913 		if (jbd2_journal_check_available_features
1914 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE))
1915 			set_opt(sbi->s_mount_opt, ORDERED_DATA);
1916 		else
1917 			set_opt(sbi->s_mount_opt, JOURNAL_DATA);
1918 		break;
1919 
1920 	case EXT4_MOUNT_ORDERED_DATA:
1921 	case EXT4_MOUNT_WRITEBACK_DATA:
1922 		if (!jbd2_journal_check_available_features
1923 		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
1924 			printk(KERN_ERR "EXT4-fs: Journal does not support "
1925 			       "requested data journaling mode\n");
1926 			goto failed_mount4;
1927 		}
1928 	default:
1929 		break;
1930 	}
1931 
1932 	if (test_opt(sb, NOBH)) {
1933 		if (!(test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)) {
1934 			printk(KERN_WARNING "EXT4-fs: Ignoring nobh option - "
1935 				"its supported only with writeback mode\n");
1936 			clear_opt(sbi->s_mount_opt, NOBH);
1937 		}
1938 	}
1939 	/*
1940 	 * The jbd2_journal_load will have done any necessary log recovery,
1941 	 * so we can safely mount the rest of the filesystem now.
1942 	 */
1943 
1944 	root = iget(sb, EXT4_ROOT_INO);
1945 	sb->s_root = d_alloc_root(root);
1946 	if (!sb->s_root) {
1947 		printk(KERN_ERR "EXT4-fs: get root inode failed\n");
1948 		iput(root);
1949 		goto failed_mount4;
1950 	}
1951 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1952 		dput(sb->s_root);
1953 		sb->s_root = NULL;
1954 		printk(KERN_ERR "EXT4-fs: corrupt root inode, run e2fsck\n");
1955 		goto failed_mount4;
1956 	}
1957 
1958 	ext4_setup_super (sb, es, sb->s_flags & MS_RDONLY);
1959 
1960 	/* determine the minimum size of new large inodes, if present */
1961 	if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
1962 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
1963 						     EXT4_GOOD_OLD_INODE_SIZE;
1964 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
1965 				       EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE)) {
1966 			if (sbi->s_want_extra_isize <
1967 			    le16_to_cpu(es->s_want_extra_isize))
1968 				sbi->s_want_extra_isize =
1969 					le16_to_cpu(es->s_want_extra_isize);
1970 			if (sbi->s_want_extra_isize <
1971 			    le16_to_cpu(es->s_min_extra_isize))
1972 				sbi->s_want_extra_isize =
1973 					le16_to_cpu(es->s_min_extra_isize);
1974 		}
1975 	}
1976 	/* Check if enough inode space is available */
1977 	if (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize >
1978 							sbi->s_inode_size) {
1979 		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
1980 						       EXT4_GOOD_OLD_INODE_SIZE;
1981 		printk(KERN_INFO "EXT4-fs: required extra inode space not"
1982 			"available.\n");
1983 	}
1984 
1985 	/*
1986 	 * akpm: core read_super() calls in here with the superblock locked.
1987 	 * That deadlocks, because orphan cleanup needs to lock the superblock
1988 	 * in numerous places.  Here we just pop the lock - it's relatively
1989 	 * harmless, because we are now ready to accept write_super() requests,
1990 	 * and aviro says that's the only reason for hanging onto the
1991 	 * superblock lock.
1992 	 */
1993 	EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
1994 	ext4_orphan_cleanup(sb, es);
1995 	EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
1996 	if (needs_recovery)
1997 		printk (KERN_INFO "EXT4-fs: recovery complete.\n");
1998 	ext4_mark_recovery_complete(sb, es);
1999 	printk (KERN_INFO "EXT4-fs: mounted filesystem with %s data mode.\n",
2000 		test_opt(sb,DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ? "journal":
2001 		test_opt(sb,DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA ? "ordered":
2002 		"writeback");
2003 
2004 	ext4_ext_init(sb);
2005 
2006 	lock_kernel();
2007 	return 0;
2008 
2009 cantfind_ext4:
2010 	if (!silent)
2011 		printk(KERN_ERR "VFS: Can't find ext4 filesystem on dev %s.\n",
2012 		       sb->s_id);
2013 	goto failed_mount;
2014 
2015 failed_mount4:
2016 	jbd2_journal_destroy(sbi->s_journal);
2017 failed_mount3:
2018 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
2019 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
2020 	percpu_counter_destroy(&sbi->s_dirs_counter);
2021 failed_mount2:
2022 	for (i = 0; i < db_count; i++)
2023 		brelse(sbi->s_group_desc[i]);
2024 	kfree(sbi->s_group_desc);
2025 failed_mount:
2026 #ifdef CONFIG_QUOTA
2027 	for (i = 0; i < MAXQUOTAS; i++)
2028 		kfree(sbi->s_qf_names[i]);
2029 #endif
2030 	ext4_blkdev_remove(sbi);
2031 	brelse(bh);
2032 out_fail:
2033 	sb->s_fs_info = NULL;
2034 	kfree(sbi);
2035 	lock_kernel();
2036 	return -EINVAL;
2037 }
2038 
2039 /*
2040  * Setup any per-fs journal parameters now.  We'll do this both on
2041  * initial mount, once the journal has been initialised but before we've
2042  * done any recovery; and again on any subsequent remount.
2043  */
2044 static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
2045 {
2046 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2047 
2048 	if (sbi->s_commit_interval)
2049 		journal->j_commit_interval = sbi->s_commit_interval;
2050 	/* We could also set up an ext4-specific default for the commit
2051 	 * interval here, but for now we'll just fall back to the jbd
2052 	 * default. */
2053 
2054 	spin_lock(&journal->j_state_lock);
2055 	if (test_opt(sb, BARRIER))
2056 		journal->j_flags |= JBD2_BARRIER;
2057 	else
2058 		journal->j_flags &= ~JBD2_BARRIER;
2059 	spin_unlock(&journal->j_state_lock);
2060 }
2061 
2062 static journal_t *ext4_get_journal(struct super_block *sb,
2063 				   unsigned int journal_inum)
2064 {
2065 	struct inode *journal_inode;
2066 	journal_t *journal;
2067 
2068 	/* First, test for the existence of a valid inode on disk.  Bad
2069 	 * things happen if we iget() an unused inode, as the subsequent
2070 	 * iput() will try to delete it. */
2071 
2072 	journal_inode = iget(sb, journal_inum);
2073 	if (!journal_inode) {
2074 		printk(KERN_ERR "EXT4-fs: no journal found.\n");
2075 		return NULL;
2076 	}
2077 	if (!journal_inode->i_nlink) {
2078 		make_bad_inode(journal_inode);
2079 		iput(journal_inode);
2080 		printk(KERN_ERR "EXT4-fs: journal inode is deleted.\n");
2081 		return NULL;
2082 	}
2083 
2084 	jbd_debug(2, "Journal inode found at %p: %Ld bytes\n",
2085 		  journal_inode, journal_inode->i_size);
2086 	if (is_bad_inode(journal_inode) || !S_ISREG(journal_inode->i_mode)) {
2087 		printk(KERN_ERR "EXT4-fs: invalid journal inode.\n");
2088 		iput(journal_inode);
2089 		return NULL;
2090 	}
2091 
2092 	journal = jbd2_journal_init_inode(journal_inode);
2093 	if (!journal) {
2094 		printk(KERN_ERR "EXT4-fs: Could not load journal inode\n");
2095 		iput(journal_inode);
2096 		return NULL;
2097 	}
2098 	journal->j_private = sb;
2099 	ext4_init_journal_params(sb, journal);
2100 	return journal;
2101 }
2102 
2103 static journal_t *ext4_get_dev_journal(struct super_block *sb,
2104 				       dev_t j_dev)
2105 {
2106 	struct buffer_head * bh;
2107 	journal_t *journal;
2108 	ext4_fsblk_t start;
2109 	ext4_fsblk_t len;
2110 	int hblock, blocksize;
2111 	ext4_fsblk_t sb_block;
2112 	unsigned long offset;
2113 	struct ext4_super_block * es;
2114 	struct block_device *bdev;
2115 
2116 	bdev = ext4_blkdev_get(j_dev);
2117 	if (bdev == NULL)
2118 		return NULL;
2119 
2120 	if (bd_claim(bdev, sb)) {
2121 		printk(KERN_ERR
2122 			"EXT4: failed to claim external journal device.\n");
2123 		blkdev_put(bdev);
2124 		return NULL;
2125 	}
2126 
2127 	blocksize = sb->s_blocksize;
2128 	hblock = bdev_hardsect_size(bdev);
2129 	if (blocksize < hblock) {
2130 		printk(KERN_ERR
2131 			"EXT4-fs: blocksize too small for journal device.\n");
2132 		goto out_bdev;
2133 	}
2134 
2135 	sb_block = EXT4_MIN_BLOCK_SIZE / blocksize;
2136 	offset = EXT4_MIN_BLOCK_SIZE % blocksize;
2137 	set_blocksize(bdev, blocksize);
2138 	if (!(bh = __bread(bdev, sb_block, blocksize))) {
2139 		printk(KERN_ERR "EXT4-fs: couldn't read superblock of "
2140 		       "external journal\n");
2141 		goto out_bdev;
2142 	}
2143 
2144 	es = (struct ext4_super_block *) (((char *)bh->b_data) + offset);
2145 	if ((le16_to_cpu(es->s_magic) != EXT4_SUPER_MAGIC) ||
2146 	    !(le32_to_cpu(es->s_feature_incompat) &
2147 	      EXT4_FEATURE_INCOMPAT_JOURNAL_DEV)) {
2148 		printk(KERN_ERR "EXT4-fs: external journal has "
2149 					"bad superblock\n");
2150 		brelse(bh);
2151 		goto out_bdev;
2152 	}
2153 
2154 	if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
2155 		printk(KERN_ERR "EXT4-fs: journal UUID does not match\n");
2156 		brelse(bh);
2157 		goto out_bdev;
2158 	}
2159 
2160 	len = ext4_blocks_count(es);
2161 	start = sb_block + 1;
2162 	brelse(bh);	/* we're done with the superblock */
2163 
2164 	journal = jbd2_journal_init_dev(bdev, sb->s_bdev,
2165 					start, len, blocksize);
2166 	if (!journal) {
2167 		printk(KERN_ERR "EXT4-fs: failed to create device journal\n");
2168 		goto out_bdev;
2169 	}
2170 	journal->j_private = sb;
2171 	ll_rw_block(READ, 1, &journal->j_sb_buffer);
2172 	wait_on_buffer(journal->j_sb_buffer);
2173 	if (!buffer_uptodate(journal->j_sb_buffer)) {
2174 		printk(KERN_ERR "EXT4-fs: I/O error on journal device\n");
2175 		goto out_journal;
2176 	}
2177 	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
2178 		printk(KERN_ERR "EXT4-fs: External journal has more than one "
2179 					"user (unsupported) - %d\n",
2180 			be32_to_cpu(journal->j_superblock->s_nr_users));
2181 		goto out_journal;
2182 	}
2183 	EXT4_SB(sb)->journal_bdev = bdev;
2184 	ext4_init_journal_params(sb, journal);
2185 	return journal;
2186 out_journal:
2187 	jbd2_journal_destroy(journal);
2188 out_bdev:
2189 	ext4_blkdev_put(bdev);
2190 	return NULL;
2191 }
2192 
2193 static int ext4_load_journal(struct super_block *sb,
2194 			     struct ext4_super_block *es,
2195 			     unsigned long journal_devnum)
2196 {
2197 	journal_t *journal;
2198 	unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
2199 	dev_t journal_dev;
2200 	int err = 0;
2201 	int really_read_only;
2202 
2203 	if (journal_devnum &&
2204 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
2205 		printk(KERN_INFO "EXT4-fs: external journal device major/minor "
2206 			"numbers have changed\n");
2207 		journal_dev = new_decode_dev(journal_devnum);
2208 	} else
2209 		journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));
2210 
2211 	really_read_only = bdev_read_only(sb->s_bdev);
2212 
2213 	/*
2214 	 * Are we loading a blank journal or performing recovery after a
2215 	 * crash?  For recovery, we need to check in advance whether we
2216 	 * can get read-write access to the device.
2217 	 */
2218 
2219 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
2220 		if (sb->s_flags & MS_RDONLY) {
2221 			printk(KERN_INFO "EXT4-fs: INFO: recovery "
2222 					"required on readonly filesystem.\n");
2223 			if (really_read_only) {
2224 				printk(KERN_ERR "EXT4-fs: write access "
2225 					"unavailable, cannot proceed.\n");
2226 				return -EROFS;
2227 			}
2228 			printk (KERN_INFO "EXT4-fs: write access will "
2229 					"be enabled during recovery.\n");
2230 		}
2231 	}
2232 
2233 	if (journal_inum && journal_dev) {
2234 		printk(KERN_ERR "EXT4-fs: filesystem has both journal "
2235 		       "and inode journals!\n");
2236 		return -EINVAL;
2237 	}
2238 
2239 	if (journal_inum) {
2240 		if (!(journal = ext4_get_journal(sb, journal_inum)))
2241 			return -EINVAL;
2242 	} else {
2243 		if (!(journal = ext4_get_dev_journal(sb, journal_dev)))
2244 			return -EINVAL;
2245 	}
2246 
2247 	if (!really_read_only && test_opt(sb, UPDATE_JOURNAL)) {
2248 		err = jbd2_journal_update_format(journal);
2249 		if (err)  {
2250 			printk(KERN_ERR "EXT4-fs: error updating journal.\n");
2251 			jbd2_journal_destroy(journal);
2252 			return err;
2253 		}
2254 	}
2255 
2256 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER))
2257 		err = jbd2_journal_wipe(journal, !really_read_only);
2258 	if (!err)
2259 		err = jbd2_journal_load(journal);
2260 
2261 	if (err) {
2262 		printk(KERN_ERR "EXT4-fs: error loading journal.\n");
2263 		jbd2_journal_destroy(journal);
2264 		return err;
2265 	}
2266 
2267 	EXT4_SB(sb)->s_journal = journal;
2268 	ext4_clear_journal_err(sb, es);
2269 
2270 	if (journal_devnum &&
2271 	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
2272 		es->s_journal_dev = cpu_to_le32(journal_devnum);
2273 		sb->s_dirt = 1;
2274 
2275 		/* Make sure we flush the recovery flag to disk. */
2276 		ext4_commit_super(sb, es, 1);
2277 	}
2278 
2279 	return 0;
2280 }
2281 
2282 static int ext4_create_journal(struct super_block * sb,
2283 			       struct ext4_super_block * es,
2284 			       unsigned int journal_inum)
2285 {
2286 	journal_t *journal;
2287 	int err;
2288 
2289 	if (sb->s_flags & MS_RDONLY) {
2290 		printk(KERN_ERR "EXT4-fs: readonly filesystem when trying to "
2291 				"create journal.\n");
2292 		return -EROFS;
2293 	}
2294 
2295 	journal = ext4_get_journal(sb, journal_inum);
2296 	if (!journal)
2297 		return -EINVAL;
2298 
2299 	printk(KERN_INFO "EXT4-fs: creating new journal on inode %u\n",
2300 	       journal_inum);
2301 
2302 	err = jbd2_journal_create(journal);
2303 	if (err) {
2304 		printk(KERN_ERR "EXT4-fs: error creating journal.\n");
2305 		jbd2_journal_destroy(journal);
2306 		return -EIO;
2307 	}
2308 
2309 	EXT4_SB(sb)->s_journal = journal;
2310 
2311 	ext4_update_dynamic_rev(sb);
2312 	EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
2313 	EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL);
2314 
2315 	es->s_journal_inum = cpu_to_le32(journal_inum);
2316 	sb->s_dirt = 1;
2317 
2318 	/* Make sure we flush the recovery flag to disk. */
2319 	ext4_commit_super(sb, es, 1);
2320 
2321 	return 0;
2322 }
2323 
2324 static void ext4_commit_super (struct super_block * sb,
2325 			       struct ext4_super_block * es,
2326 			       int sync)
2327 {
2328 	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
2329 
2330 	if (!sbh)
2331 		return;
2332 	es->s_wtime = cpu_to_le32(get_seconds());
2333 	ext4_free_blocks_count_set(es, ext4_count_free_blocks(sb));
2334 	es->s_free_inodes_count = cpu_to_le32(ext4_count_free_inodes(sb));
2335 	BUFFER_TRACE(sbh, "marking dirty");
2336 	mark_buffer_dirty(sbh);
2337 	if (sync)
2338 		sync_dirty_buffer(sbh);
2339 }
2340 
2341 
2342 /*
2343  * Have we just finished recovery?  If so, and if we are mounting (or
2344  * remounting) the filesystem readonly, then we will end up with a
2345  * consistent fs on disk.  Record that fact.
2346  */
2347 static void ext4_mark_recovery_complete(struct super_block * sb,
2348 					struct ext4_super_block * es)
2349 {
2350 	journal_t *journal = EXT4_SB(sb)->s_journal;
2351 
2352 	jbd2_journal_lock_updates(journal);
2353 	jbd2_journal_flush(journal);
2354 	lock_super(sb);
2355 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER) &&
2356 	    sb->s_flags & MS_RDONLY) {
2357 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
2358 		sb->s_dirt = 0;
2359 		ext4_commit_super(sb, es, 1);
2360 	}
2361 	unlock_super(sb);
2362 	jbd2_journal_unlock_updates(journal);
2363 }
2364 
2365 /*
2366  * If we are mounting (or read-write remounting) a filesystem whose journal
2367  * has recorded an error from a previous lifetime, move that error to the
2368  * main filesystem now.
2369  */
2370 static void ext4_clear_journal_err(struct super_block * sb,
2371 				   struct ext4_super_block * es)
2372 {
2373 	journal_t *journal;
2374 	int j_errno;
2375 	const char *errstr;
2376 
2377 	journal = EXT4_SB(sb)->s_journal;
2378 
2379 	/*
2380 	 * Now check for any error status which may have been recorded in the
2381 	 * journal by a prior ext4_error() or ext4_abort()
2382 	 */
2383 
2384 	j_errno = jbd2_journal_errno(journal);
2385 	if (j_errno) {
2386 		char nbuf[16];
2387 
2388 		errstr = ext4_decode_error(sb, j_errno, nbuf);
2389 		ext4_warning(sb, __FUNCTION__, "Filesystem error recorded "
2390 			     "from previous mount: %s", errstr);
2391 		ext4_warning(sb, __FUNCTION__, "Marking fs in need of "
2392 			     "filesystem check.");
2393 
2394 		EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
2395 		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
2396 		ext4_commit_super (sb, es, 1);
2397 
2398 		jbd2_journal_clear_err(journal);
2399 	}
2400 }
2401 
2402 /*
2403  * Force the running and committing transactions to commit,
2404  * and wait on the commit.
2405  */
2406 int ext4_force_commit(struct super_block *sb)
2407 {
2408 	journal_t *journal;
2409 	int ret;
2410 
2411 	if (sb->s_flags & MS_RDONLY)
2412 		return 0;
2413 
2414 	journal = EXT4_SB(sb)->s_journal;
2415 	sb->s_dirt = 0;
2416 	ret = ext4_journal_force_commit(journal);
2417 	return ret;
2418 }
2419 
2420 /*
2421  * Ext4 always journals updates to the superblock itself, so we don't
2422  * have to propagate any other updates to the superblock on disk at this
2423  * point.  Just start an async writeback to get the buffers on their way
2424  * to the disk.
2425  *
2426  * This implicitly triggers the writebehind on sync().
2427  */
2428 
2429 static void ext4_write_super (struct super_block * sb)
2430 {
2431 	if (mutex_trylock(&sb->s_lock) != 0)
2432 		BUG();
2433 	sb->s_dirt = 0;
2434 }
2435 
2436 static int ext4_sync_fs(struct super_block *sb, int wait)
2437 {
2438 	tid_t target;
2439 
2440 	sb->s_dirt = 0;
2441 	if (jbd2_journal_start_commit(EXT4_SB(sb)->s_journal, &target)) {
2442 		if (wait)
2443 			jbd2_log_wait_commit(EXT4_SB(sb)->s_journal, target);
2444 	}
2445 	return 0;
2446 }
2447 
2448 /*
2449  * LVM calls this function before a (read-only) snapshot is created.  This
2450  * gives us a chance to flush the journal completely and mark the fs clean.
2451  */
2452 static void ext4_write_super_lockfs(struct super_block *sb)
2453 {
2454 	sb->s_dirt = 0;
2455 
2456 	if (!(sb->s_flags & MS_RDONLY)) {
2457 		journal_t *journal = EXT4_SB(sb)->s_journal;
2458 
2459 		/* Now we set up the journal barrier. */
2460 		jbd2_journal_lock_updates(journal);
2461 		jbd2_journal_flush(journal);
2462 
2463 		/* Journal blocked and flushed, clear needs_recovery flag. */
2464 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
2465 		ext4_commit_super(sb, EXT4_SB(sb)->s_es, 1);
2466 	}
2467 }
2468 
2469 /*
2470  * Called by LVM after the snapshot is done.  We need to reset the RECOVER
2471  * flag here, even though the filesystem is not technically dirty yet.
2472  */
2473 static void ext4_unlockfs(struct super_block *sb)
2474 {
2475 	if (!(sb->s_flags & MS_RDONLY)) {
2476 		lock_super(sb);
2477 		/* Reser the needs_recovery flag before the fs is unlocked. */
2478 		EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
2479 		ext4_commit_super(sb, EXT4_SB(sb)->s_es, 1);
2480 		unlock_super(sb);
2481 		jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
2482 	}
2483 }
2484 
2485 static int ext4_remount (struct super_block * sb, int * flags, char * data)
2486 {
2487 	struct ext4_super_block * es;
2488 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2489 	ext4_fsblk_t n_blocks_count = 0;
2490 	unsigned long old_sb_flags;
2491 	struct ext4_mount_options old_opts;
2492 	int err;
2493 #ifdef CONFIG_QUOTA
2494 	int i;
2495 #endif
2496 
2497 	/* Store the original options */
2498 	old_sb_flags = sb->s_flags;
2499 	old_opts.s_mount_opt = sbi->s_mount_opt;
2500 	old_opts.s_resuid = sbi->s_resuid;
2501 	old_opts.s_resgid = sbi->s_resgid;
2502 	old_opts.s_commit_interval = sbi->s_commit_interval;
2503 #ifdef CONFIG_QUOTA
2504 	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
2505 	for (i = 0; i < MAXQUOTAS; i++)
2506 		old_opts.s_qf_names[i] = sbi->s_qf_names[i];
2507 #endif
2508 
2509 	/*
2510 	 * Allow the "check" option to be passed as a remount option.
2511 	 */
2512 	if (!parse_options(data, sb, NULL, NULL, &n_blocks_count, 1)) {
2513 		err = -EINVAL;
2514 		goto restore_opts;
2515 	}
2516 
2517 	if (sbi->s_mount_opt & EXT4_MOUNT_ABORT)
2518 		ext4_abort(sb, __FUNCTION__, "Abort forced by user");
2519 
2520 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
2521 		((sbi->s_mount_opt & EXT4_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
2522 
2523 	es = sbi->s_es;
2524 
2525 	ext4_init_journal_params(sb, sbi->s_journal);
2526 
2527 	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY) ||
2528 		n_blocks_count > ext4_blocks_count(es)) {
2529 		if (sbi->s_mount_opt & EXT4_MOUNT_ABORT) {
2530 			err = -EROFS;
2531 			goto restore_opts;
2532 		}
2533 
2534 		if (*flags & MS_RDONLY) {
2535 			/*
2536 			 * First of all, the unconditional stuff we have to do
2537 			 * to disable replay of the journal when we next remount
2538 			 */
2539 			sb->s_flags |= MS_RDONLY;
2540 
2541 			/*
2542 			 * OK, test if we are remounting a valid rw partition
2543 			 * readonly, and if so set the rdonly flag and then
2544 			 * mark the partition as valid again.
2545 			 */
2546 			if (!(es->s_state & cpu_to_le16(EXT4_VALID_FS)) &&
2547 			    (sbi->s_mount_state & EXT4_VALID_FS))
2548 				es->s_state = cpu_to_le16(sbi->s_mount_state);
2549 
2550 			/*
2551 			 * We have to unlock super so that we can wait for
2552 			 * transactions.
2553 			 */
2554 			unlock_super(sb);
2555 			ext4_mark_recovery_complete(sb, es);
2556 			lock_super(sb);
2557 		} else {
2558 			__le32 ret;
2559 			if ((ret = EXT4_HAS_RO_COMPAT_FEATURE(sb,
2560 					~EXT4_FEATURE_RO_COMPAT_SUPP))) {
2561 				printk(KERN_WARNING "EXT4-fs: %s: couldn't "
2562 				       "remount RDWR because of unsupported "
2563 				       "optional features (%x).\n",
2564 				       sb->s_id, le32_to_cpu(ret));
2565 				err = -EROFS;
2566 				goto restore_opts;
2567 			}
2568 
2569 			/*
2570 			 * If we have an unprocessed orphan list hanging
2571 			 * around from a previously readonly bdev mount,
2572 			 * require a full umount/remount for now.
2573 			 */
2574 			if (es->s_last_orphan) {
2575 				printk(KERN_WARNING "EXT4-fs: %s: couldn't "
2576 				       "remount RDWR because of unprocessed "
2577 				       "orphan inode list.  Please "
2578 				       "umount/remount instead.\n",
2579 				       sb->s_id);
2580 				err = -EINVAL;
2581 				goto restore_opts;
2582 			}
2583 
2584 			/*
2585 			 * Mounting a RDONLY partition read-write, so reread
2586 			 * and store the current valid flag.  (It may have
2587 			 * been changed by e2fsck since we originally mounted
2588 			 * the partition.)
2589 			 */
2590 			ext4_clear_journal_err(sb, es);
2591 			sbi->s_mount_state = le16_to_cpu(es->s_state);
2592 			if ((err = ext4_group_extend(sb, es, n_blocks_count)))
2593 				goto restore_opts;
2594 			if (!ext4_setup_super (sb, es, 0))
2595 				sb->s_flags &= ~MS_RDONLY;
2596 		}
2597 	}
2598 #ifdef CONFIG_QUOTA
2599 	/* Release old quota file names */
2600 	for (i = 0; i < MAXQUOTAS; i++)
2601 		if (old_opts.s_qf_names[i] &&
2602 		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
2603 			kfree(old_opts.s_qf_names[i]);
2604 #endif
2605 	return 0;
2606 restore_opts:
2607 	sb->s_flags = old_sb_flags;
2608 	sbi->s_mount_opt = old_opts.s_mount_opt;
2609 	sbi->s_resuid = old_opts.s_resuid;
2610 	sbi->s_resgid = old_opts.s_resgid;
2611 	sbi->s_commit_interval = old_opts.s_commit_interval;
2612 #ifdef CONFIG_QUOTA
2613 	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
2614 	for (i = 0; i < MAXQUOTAS; i++) {
2615 		if (sbi->s_qf_names[i] &&
2616 		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
2617 			kfree(sbi->s_qf_names[i]);
2618 		sbi->s_qf_names[i] = old_opts.s_qf_names[i];
2619 	}
2620 #endif
2621 	return err;
2622 }
2623 
2624 static int ext4_statfs (struct dentry * dentry, struct kstatfs * buf)
2625 {
2626 	struct super_block *sb = dentry->d_sb;
2627 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2628 	struct ext4_super_block *es = sbi->s_es;
2629 	u64 fsid;
2630 
2631 	if (test_opt(sb, MINIX_DF)) {
2632 		sbi->s_overhead_last = 0;
2633 	} else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
2634 		unsigned long ngroups = sbi->s_groups_count, i;
2635 		ext4_fsblk_t overhead = 0;
2636 		smp_rmb();
2637 
2638 		/*
2639 		 * Compute the overhead (FS structures).  This is constant
2640 		 * for a given filesystem unless the number of block groups
2641 		 * changes so we cache the previous value until it does.
2642 		 */
2643 
2644 		/*
2645 		 * All of the blocks before first_data_block are
2646 		 * overhead
2647 		 */
2648 		overhead = le32_to_cpu(es->s_first_data_block);
2649 
2650 		/*
2651 		 * Add the overhead attributed to the superblock and
2652 		 * block group descriptors.  If the sparse superblocks
2653 		 * feature is turned on, then not all groups have this.
2654 		 */
2655 		for (i = 0; i < ngroups; i++) {
2656 			overhead += ext4_bg_has_super(sb, i) +
2657 				ext4_bg_num_gdb(sb, i);
2658 			cond_resched();
2659 		}
2660 
2661 		/*
2662 		 * Every block group has an inode bitmap, a block
2663 		 * bitmap, and an inode table.
2664 		 */
2665 		overhead += ngroups * (2 + sbi->s_itb_per_group);
2666 		sbi->s_overhead_last = overhead;
2667 		smp_wmb();
2668 		sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
2669 	}
2670 
2671 	buf->f_type = EXT4_SUPER_MAGIC;
2672 	buf->f_bsize = sb->s_blocksize;
2673 	buf->f_blocks = ext4_blocks_count(es) - sbi->s_overhead_last;
2674 	buf->f_bfree = percpu_counter_sum_positive(&sbi->s_freeblocks_counter);
2675 	es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
2676 	buf->f_bavail = buf->f_bfree - ext4_r_blocks_count(es);
2677 	if (buf->f_bfree < ext4_r_blocks_count(es))
2678 		buf->f_bavail = 0;
2679 	buf->f_files = le32_to_cpu(es->s_inodes_count);
2680 	buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter);
2681 	es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
2682 	buf->f_namelen = EXT4_NAME_LEN;
2683 	fsid = le64_to_cpup((void *)es->s_uuid) ^
2684 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
2685 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
2686 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
2687 	return 0;
2688 }
2689 
2690 /* Helper function for writing quotas on sync - we need to start transaction before quota file
2691  * is locked for write. Otherwise the are possible deadlocks:
2692  * Process 1                         Process 2
2693  * ext4_create()                     quota_sync()
2694  *   jbd2_journal_start()                   write_dquot()
2695  *   DQUOT_INIT()                        down(dqio_mutex)
2696  *     down(dqio_mutex)                    jbd2_journal_start()
2697  *
2698  */
2699 
2700 #ifdef CONFIG_QUOTA
2701 
2702 static inline struct inode *dquot_to_inode(struct dquot *dquot)
2703 {
2704 	return sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
2705 }
2706 
2707 static int ext4_dquot_initialize(struct inode *inode, int type)
2708 {
2709 	handle_t *handle;
2710 	int ret, err;
2711 
2712 	/* We may create quota structure so we need to reserve enough blocks */
2713 	handle = ext4_journal_start(inode, 2*EXT4_QUOTA_INIT_BLOCKS(inode->i_sb));
2714 	if (IS_ERR(handle))
2715 		return PTR_ERR(handle);
2716 	ret = dquot_initialize(inode, type);
2717 	err = ext4_journal_stop(handle);
2718 	if (!ret)
2719 		ret = err;
2720 	return ret;
2721 }
2722 
2723 static int ext4_dquot_drop(struct inode *inode)
2724 {
2725 	handle_t *handle;
2726 	int ret, err;
2727 
2728 	/* We may delete quota structure so we need to reserve enough blocks */
2729 	handle = ext4_journal_start(inode, 2*EXT4_QUOTA_DEL_BLOCKS(inode->i_sb));
2730 	if (IS_ERR(handle))
2731 		return PTR_ERR(handle);
2732 	ret = dquot_drop(inode);
2733 	err = ext4_journal_stop(handle);
2734 	if (!ret)
2735 		ret = err;
2736 	return ret;
2737 }
2738 
2739 static int ext4_write_dquot(struct dquot *dquot)
2740 {
2741 	int ret, err;
2742 	handle_t *handle;
2743 	struct inode *inode;
2744 
2745 	inode = dquot_to_inode(dquot);
2746 	handle = ext4_journal_start(inode,
2747 					EXT4_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
2748 	if (IS_ERR(handle))
2749 		return PTR_ERR(handle);
2750 	ret = dquot_commit(dquot);
2751 	err = ext4_journal_stop(handle);
2752 	if (!ret)
2753 		ret = err;
2754 	return ret;
2755 }
2756 
2757 static int ext4_acquire_dquot(struct dquot *dquot)
2758 {
2759 	int ret, err;
2760 	handle_t *handle;
2761 
2762 	handle = ext4_journal_start(dquot_to_inode(dquot),
2763 					EXT4_QUOTA_INIT_BLOCKS(dquot->dq_sb));
2764 	if (IS_ERR(handle))
2765 		return PTR_ERR(handle);
2766 	ret = dquot_acquire(dquot);
2767 	err = ext4_journal_stop(handle);
2768 	if (!ret)
2769 		ret = err;
2770 	return ret;
2771 }
2772 
2773 static int ext4_release_dquot(struct dquot *dquot)
2774 {
2775 	int ret, err;
2776 	handle_t *handle;
2777 
2778 	handle = ext4_journal_start(dquot_to_inode(dquot),
2779 					EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
2780 	if (IS_ERR(handle)) {
2781 		/* Release dquot anyway to avoid endless cycle in dqput() */
2782 		dquot_release(dquot);
2783 		return PTR_ERR(handle);
2784 	}
2785 	ret = dquot_release(dquot);
2786 	err = ext4_journal_stop(handle);
2787 	if (!ret)
2788 		ret = err;
2789 	return ret;
2790 }
2791 
2792 static int ext4_mark_dquot_dirty(struct dquot *dquot)
2793 {
2794 	/* Are we journalling quotas? */
2795 	if (EXT4_SB(dquot->dq_sb)->s_qf_names[USRQUOTA] ||
2796 	    EXT4_SB(dquot->dq_sb)->s_qf_names[GRPQUOTA]) {
2797 		dquot_mark_dquot_dirty(dquot);
2798 		return ext4_write_dquot(dquot);
2799 	} else {
2800 		return dquot_mark_dquot_dirty(dquot);
2801 	}
2802 }
2803 
2804 static int ext4_write_info(struct super_block *sb, int type)
2805 {
2806 	int ret, err;
2807 	handle_t *handle;
2808 
2809 	/* Data block + inode block */
2810 	handle = ext4_journal_start(sb->s_root->d_inode, 2);
2811 	if (IS_ERR(handle))
2812 		return PTR_ERR(handle);
2813 	ret = dquot_commit_info(sb, type);
2814 	err = ext4_journal_stop(handle);
2815 	if (!ret)
2816 		ret = err;
2817 	return ret;
2818 }
2819 
2820 /*
2821  * Turn on quotas during mount time - we need to find
2822  * the quota file and such...
2823  */
2824 static int ext4_quota_on_mount(struct super_block *sb, int type)
2825 {
2826 	return vfs_quota_on_mount(sb, EXT4_SB(sb)->s_qf_names[type],
2827 			EXT4_SB(sb)->s_jquota_fmt, type);
2828 }
2829 
2830 /*
2831  * Standard function to be called on quota_on
2832  */
2833 static int ext4_quota_on(struct super_block *sb, int type, int format_id,
2834 			 char *path)
2835 {
2836 	int err;
2837 	struct nameidata nd;
2838 
2839 	if (!test_opt(sb, QUOTA))
2840 		return -EINVAL;
2841 	/* Not journalling quota? */
2842 	if (!EXT4_SB(sb)->s_qf_names[USRQUOTA] &&
2843 	    !EXT4_SB(sb)->s_qf_names[GRPQUOTA])
2844 		return vfs_quota_on(sb, type, format_id, path);
2845 	err = path_lookup(path, LOOKUP_FOLLOW, &nd);
2846 	if (err)
2847 		return err;
2848 	/* Quotafile not on the same filesystem? */
2849 	if (nd.mnt->mnt_sb != sb) {
2850 		path_release(&nd);
2851 		return -EXDEV;
2852 	}
2853 	/* Quotafile not of fs root? */
2854 	if (nd.dentry->d_parent->d_inode != sb->s_root->d_inode)
2855 		printk(KERN_WARNING
2856 			"EXT4-fs: Quota file not on filesystem root. "
2857 			"Journalled quota will not work.\n");
2858 	path_release(&nd);
2859 	return vfs_quota_on(sb, type, format_id, path);
2860 }
2861 
2862 /* Read data from quotafile - avoid pagecache and such because we cannot afford
2863  * acquiring the locks... As quota files are never truncated and quota code
2864  * itself serializes the operations (and noone else should touch the files)
2865  * we don't have to be afraid of races */
2866 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
2867 			       size_t len, loff_t off)
2868 {
2869 	struct inode *inode = sb_dqopt(sb)->files[type];
2870 	sector_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
2871 	int err = 0;
2872 	int offset = off & (sb->s_blocksize - 1);
2873 	int tocopy;
2874 	size_t toread;
2875 	struct buffer_head *bh;
2876 	loff_t i_size = i_size_read(inode);
2877 
2878 	if (off > i_size)
2879 		return 0;
2880 	if (off+len > i_size)
2881 		len = i_size-off;
2882 	toread = len;
2883 	while (toread > 0) {
2884 		tocopy = sb->s_blocksize - offset < toread ?
2885 				sb->s_blocksize - offset : toread;
2886 		bh = ext4_bread(NULL, inode, blk, 0, &err);
2887 		if (err)
2888 			return err;
2889 		if (!bh)	/* A hole? */
2890 			memset(data, 0, tocopy);
2891 		else
2892 			memcpy(data, bh->b_data+offset, tocopy);
2893 		brelse(bh);
2894 		offset = 0;
2895 		toread -= tocopy;
2896 		data += tocopy;
2897 		blk++;
2898 	}
2899 	return len;
2900 }
2901 
2902 /* Write to quotafile (we know the transaction is already started and has
2903  * enough credits) */
2904 static ssize_t ext4_quota_write(struct super_block *sb, int type,
2905 				const char *data, size_t len, loff_t off)
2906 {
2907 	struct inode *inode = sb_dqopt(sb)->files[type];
2908 	sector_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
2909 	int err = 0;
2910 	int offset = off & (sb->s_blocksize - 1);
2911 	int tocopy;
2912 	int journal_quota = EXT4_SB(sb)->s_qf_names[type] != NULL;
2913 	size_t towrite = len;
2914 	struct buffer_head *bh;
2915 	handle_t *handle = journal_current_handle();
2916 
2917 	if (!handle) {
2918 		printk(KERN_WARNING "EXT4-fs: Quota write (off=%Lu, len=%Lu)"
2919 			" cancelled because transaction is not started.\n",
2920 			(unsigned long long)off, (unsigned long long)len);
2921 		return -EIO;
2922 	}
2923 	mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
2924 	while (towrite > 0) {
2925 		tocopy = sb->s_blocksize - offset < towrite ?
2926 				sb->s_blocksize - offset : towrite;
2927 		bh = ext4_bread(handle, inode, blk, 1, &err);
2928 		if (!bh)
2929 			goto out;
2930 		if (journal_quota) {
2931 			err = ext4_journal_get_write_access(handle, bh);
2932 			if (err) {
2933 				brelse(bh);
2934 				goto out;
2935 			}
2936 		}
2937 		lock_buffer(bh);
2938 		memcpy(bh->b_data+offset, data, tocopy);
2939 		flush_dcache_page(bh->b_page);
2940 		unlock_buffer(bh);
2941 		if (journal_quota)
2942 			err = ext4_journal_dirty_metadata(handle, bh);
2943 		else {
2944 			/* Always do at least ordered writes for quotas */
2945 			err = ext4_journal_dirty_data(handle, bh);
2946 			mark_buffer_dirty(bh);
2947 		}
2948 		brelse(bh);
2949 		if (err)
2950 			goto out;
2951 		offset = 0;
2952 		towrite -= tocopy;
2953 		data += tocopy;
2954 		blk++;
2955 	}
2956 out:
2957 	if (len == towrite)
2958 		return err;
2959 	if (inode->i_size < off+len-towrite) {
2960 		i_size_write(inode, off+len-towrite);
2961 		EXT4_I(inode)->i_disksize = inode->i_size;
2962 	}
2963 	inode->i_version++;
2964 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
2965 	ext4_mark_inode_dirty(handle, inode);
2966 	mutex_unlock(&inode->i_mutex);
2967 	return len - towrite;
2968 }
2969 
2970 #endif
2971 
2972 static int ext4_get_sb(struct file_system_type *fs_type,
2973 	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
2974 {
2975 	return get_sb_bdev(fs_type, flags, dev_name, data, ext4_fill_super, mnt);
2976 }
2977 
2978 static struct file_system_type ext4dev_fs_type = {
2979 	.owner		= THIS_MODULE,
2980 	.name		= "ext4dev",
2981 	.get_sb		= ext4_get_sb,
2982 	.kill_sb	= kill_block_super,
2983 	.fs_flags	= FS_REQUIRES_DEV,
2984 };
2985 
2986 static int __init init_ext4_fs(void)
2987 {
2988 	int err = init_ext4_xattr();
2989 	if (err)
2990 		return err;
2991 	err = init_inodecache();
2992 	if (err)
2993 		goto out1;
2994 	err = register_filesystem(&ext4dev_fs_type);
2995 	if (err)
2996 		goto out;
2997 	return 0;
2998 out:
2999 	destroy_inodecache();
3000 out1:
3001 	exit_ext4_xattr();
3002 	return err;
3003 }
3004 
3005 static void __exit exit_ext4_fs(void)
3006 {
3007 	unregister_filesystem(&ext4dev_fs_type);
3008 	destroy_inodecache();
3009 	exit_ext4_xattr();
3010 }
3011 
3012 MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
3013 MODULE_DESCRIPTION("Fourth Extended Filesystem with extents");
3014 MODULE_LICENSE("GPL");
3015 module_init(init_ext4_fs)
3016 module_exit(exit_ext4_fs)
3017