Merge branch 'linux-next' of git://git.infradead.org/ubifs-2.6

* 'linux-next' of git://git.infradead.org/ubifs-2.6:
  UBIFS: remove fast unmounting
  UBIFS: return sensible error codes
  UBIFS: remount ro fixes
  UBIFS: spelling fix 'date' -> 'data'
  UBIFS: sync wbufs after syncing inodes and pages
  UBIFS: fix LPT out-of-space bug (again)
  UBIFS: fix no_chk_data_crc
  UBIFS: fix assertions
  UBIFS: ensure orphan area head is initialized
  UBIFS: always clean up GC LEB space
  UBIFS: add re-mount debugging checks
  UBIFS: fix LEB list freeing
  UBIFS: simplify locking
  UBIFS: document dark_wm and dead_wm better
  UBIFS: do not treat all data as short term
  UBIFS: constify operations
  UBIFS: do not commit twice

15 files changed, 393 insertions, 286 deletions

diff --git a/fs/ubifs/budget.c b/fs/ubifs/budget.c
index 175f9c590b7..f393620890e 100644
--- a/fs/ubifs/budget.c
+++ b/fs/ubifs/budget.c
@@ -689,7 +689,7 @@ long long ubifs_reported_space(const struct ubifs_info *c, long long free)
 }
 
 /**
- * ubifs_get_free_space - return amount of free space.
+ * ubifs_get_free_space_nolock - return amount of free space.
  * @c: UBIFS file-system description object
  *
  * This function calculates amount of free space to report to user-space.
@@ -704,16 +704,14 @@ long long ubifs_reported_space(const struct ubifs_info *c, long long free)
  * traditional file-systems, because they have way less overhead than UBIFS.
  * So, to keep users happy, UBIFS tries to take the overhead into account.
  */
-long long ubifs_get_free_space(struct ubifs_info *c)
+long long ubifs_get_free_space_nolock(struct ubifs_info *c)
 {
-	int min_idx_lebs, rsvd_idx_lebs, lebs;
+	int rsvd_idx_lebs, lebs;
 	long long available, outstanding, free;
 
-	spin_lock(&c->space_lock);
-	min_idx_lebs = c->min_idx_lebs;
-	ubifs_assert(min_idx_lebs == ubifs_calc_min_idx_lebs(c));
+	ubifs_assert(c->min_idx_lebs == ubifs_calc_min_idx_lebs(c));
 	outstanding = c->budg_data_growth + c->budg_dd_growth;
-	available = ubifs_calc_available(c, min_idx_lebs);
+	available = ubifs_calc_available(c, c->min_idx_lebs);
 
 	/*
 	 * When reporting free space to user-space, UBIFS guarantees that it is
@@ -726,15 +724,14 @@ long long ubifs_get_free_space(struct ubifs_info *c)
 	 * Note, the calculations below are similar to what we have in
 	 * 'do_budget_space()', so refer there for comments.
 	 */
-	if (min_idx_lebs > c->lst.idx_lebs)
-		rsvd_idx_lebs = min_idx_lebs - c->lst.idx_lebs;
+	if (c->min_idx_lebs > c->lst.idx_lebs)
+		rsvd_idx_lebs = c->min_idx_lebs - c->lst.idx_lebs;
 	else
 		rsvd_idx_lebs = 0;
 	lebs = c->lst.empty_lebs + c->freeable_cnt + c->idx_gc_cnt -
 	       c->lst.taken_empty_lebs;
 	lebs -= rsvd_idx_lebs;
 	available += lebs * (c->dark_wm - c->leb_overhead);
-	spin_unlock(&c->space_lock);
 
 	if (available > outstanding)
 		free = ubifs_reported_space(c, available - outstanding);
@@ -742,3 +739,21 @@ long long ubifs_get_free_space(struct ubifs_info *c)
 		free = 0;
 	return free;
 }
+
+/**
+ * ubifs_get_free_space - return amount of free space.
+ * @c: UBIFS file-system description object
+ *
+ * This function calculates and retuns amount of free space to report to
+ * user-space.
+ */
+long long ubifs_get_free_space(struct ubifs_info *c)
+{
+	long long free;
+
+	spin_lock(&c->space_lock);
+	free = ubifs_get_free_space_nolock(c);
+	spin_unlock(&c->space_lock);
+
+	return free;
+}
diff --git a/fs/ubifs/debug.c b/fs/ubifs/debug.c
index 792c5a16c18..e975bd82f38 100644
--- a/fs/ubifs/debug.c
+++ b/fs/ubifs/debug.c
@@ -620,9 +620,11 @@ void dbg_dump_budg(struct ubifs_info *c)
 	       c->dark_wm, c->dead_wm, c->max_idx_node_sz);
 	printk(KERN_DEBUG "\tgc_lnum %d, ihead_lnum %d\n",
 	       c->gc_lnum, c->ihead_lnum);
-	for (i = 0; i < c->jhead_cnt; i++)
-		printk(KERN_DEBUG "\tjhead %d\t LEB %d\n",
-		       c->jheads[i].wbuf.jhead, c->jheads[i].wbuf.lnum);
+	/* If we are in R/O mode, journal heads do not exist */
+	if (c->jheads)
+		for (i = 0; i < c->jhead_cnt; i++)
+			printk(KERN_DEBUG "\tjhead %d\t LEB %d\n",
+			       c->jheads[i].wbuf.jhead, c->jheads[i].wbuf.lnum);
 	for (rb = rb_first(&c->buds); rb; rb = rb_next(rb)) {
 		bud = rb_entry(rb, struct ubifs_bud, rb);
 		printk(KERN_DEBUG "\tbud LEB %d\n", bud->lnum);
@@ -637,10 +639,7 @@ void dbg_dump_budg(struct ubifs_info *c)
 	/* Print budgeting predictions */
 	available = ubifs_calc_available(c, c->min_idx_lebs);
 	outstanding = c->budg_data_growth + c->budg_dd_growth;
-	if (available > outstanding)
-		free = ubifs_reported_space(c, available - outstanding);
-	else
-		free = 0;
+	free = ubifs_get_free_space_nolock(c);
 	printk(KERN_DEBUG "Budgeting predictions:\n");
 	printk(KERN_DEBUG "\tavailable: %lld, outstanding %lld, free %lld\n",
 	       available, outstanding, free);
@@ -861,6 +860,65 @@ void dbg_dump_index(struct ubifs_info *c)
 }
 
 /**
+ * dbg_save_space_info - save information about flash space.
+ * @c: UBIFS file-system description object
+ *
+ * This function saves information about UBIFS free space, dirty space, etc, in
+ * order to check it later.
+ */
+void dbg_save_space_info(struct ubifs_info *c)
+{
+	struct ubifs_debug_info *d = c->dbg;
+
+	ubifs_get_lp_stats(c, &d->saved_lst);
+
+	spin_lock(&c->space_lock);
+	d->saved_free = ubifs_get_free_space_nolock(c);
+	spin_unlock(&c->space_lock);
+}
+
+/**
+ * dbg_check_space_info - check flash space information.
+ * @c: UBIFS file-system description object
+ *
+ * This function compares current flash space information with the information
+ * which was saved when the 'dbg_save_space_info()' function was called.
+ * Returns zero if the information has not changed, and %-EINVAL it it has
+ * changed.
+ */
+int dbg_check_space_info(struct ubifs_info *c)
+{
+	struct ubifs_debug_info *d = c->dbg;
+	struct ubifs_lp_stats lst;
+	long long avail, free;
+
+	spin_lock(&c->space_lock);
+	avail = ubifs_calc_available(c, c->min_idx_lebs);
+	spin_unlock(&c->space_lock);
+	free = ubifs_get_free_space(c);
+
+	if (free != d->saved_free) {
+		ubifs_err("free space changed from %lld to %lld",
+			  d->saved_free, free);
+		goto out;
+	}
+
+	return 0;
+
+out:
+	ubifs_msg("saved lprops statistics dump");
+	dbg_dump_lstats(&d->saved_lst);
+	ubifs_get_lp_stats(c, &lst);
+	ubifs_msg("current lprops statistics dump");
+	dbg_dump_lstats(&d->saved_lst);
+	spin_lock(&c->space_lock);
+	dbg_dump_budg(c);
+	spin_unlock(&c->space_lock);
+	dump_stack();
+	return -EINVAL;
+}
+
+/**
  * dbg_check_synced_i_size - check synchronized inode size.
  * @inode: inode to check
  *
@@ -1349,7 +1407,7 @@ int dbg_check_tnc(struct ubifs_info *c, int extra)
  * @c: UBIFS file-system description object
  * @leaf_cb: called for each leaf node
  * @znode_cb: called for each indexing node
- * @priv: private date which is passed to callbacks
+ * @priv: private data which is passed to callbacks
  *
  * This function walks the UBIFS index and calls the @leaf_cb for each leaf
  * node and @znode_cb for each indexing node. Returns zero in case of success
@@ -2409,7 +2467,7 @@ void ubifs_debugging_exit(struct ubifs_info *c)
  * Root directory for UBIFS stuff in debugfs. Contains sub-directories which
  * contain the stuff specific to particular file-system mounts.
  */
-static struct dentry *debugfs_rootdir;
+static struct dentry *dfs_rootdir;
 
 /**
  * dbg_debugfs_init - initialize debugfs file-system.
@@ -2421,9 +2479,9 @@ static struct dentry *debugfs_rootdir;
  */
 int dbg_debugfs_init(void)
 {
-	debugfs_rootdir = debugfs_create_dir("ubifs", NULL);
-	if (IS_ERR(debugfs_rootdir)) {
-		int err = PTR_ERR(debugfs_rootdir);
+	dfs_rootdir = debugfs_create_dir("ubifs", NULL);
+	if (IS_ERR(dfs_rootdir)) {
+		int err = PTR_ERR(dfs_rootdir);
 		ubifs_err("cannot create \"ubifs\" debugfs directory, "
 			  "error %d\n", err);
 		return err;
@@ -2437,7 +2495,7 @@ int dbg_debugfs_init(void)
  */
 void dbg_debugfs_exit(void)
 {
-	debugfs_remove(debugfs_rootdir);
+	debugfs_remove(dfs_rootdir);
 }
 
 static int open_debugfs_file(struct inode *inode, struct file *file)
@@ -2452,13 +2510,13 @@ static ssize_t write_debugfs_file(struct file *file, const char __user *buf,
 	struct ubifs_info *c = file->private_data;
 	struct ubifs_debug_info *d = c->dbg;
 
-	if (file->f_path.dentry == d->dump_lprops)
+	if (file->f_path.dentry == d->dfs_dump_lprops)
 		dbg_dump_lprops(c);
-	else if (file->f_path.dentry == d->dump_budg) {
+	else if (file->f_path.dentry == d->dfs_dump_budg) {
 		spin_lock(&c->space_lock);
 		dbg_dump_budg(c);
 		spin_unlock(&c->space_lock);
-	} else if (file->f_path.dentry == d->dump_tnc) {
+	} else if (file->f_path.dentry == d->dfs_dump_tnc) {
 		mutex_lock(&c->tnc_mutex);
 		dbg_dump_tnc(c);
 		mutex_unlock(&c->tnc_mutex);
@@ -2469,7 +2527,7 @@ static ssize_t write_debugfs_file(struct file *file, const char __user *buf,
 	return count;
 }
 
-static const struct file_operations debugfs_fops = {
+static const struct file_operations dfs_fops = {
 	.open = open_debugfs_file,
 	.write = write_debugfs_file,
 	.owner = THIS_MODULE,
@@ -2494,36 +2552,32 @@ int dbg_debugfs_init_fs(struct ubifs_info *c)
 	struct dentry *dent;
 	struct ubifs_debug_info *d = c->dbg;
 
-	sprintf(d->debugfs_dir_name, "ubi%d_%d", c->vi.ubi_num, c->vi.vol_id);
-	d->debugfs_dir = debugfs_create_dir(d->debugfs_dir_name,
-					      debugfs_rootdir);
-	if (IS_ERR(d->debugfs_dir)) {
-		err = PTR_ERR(d->debugfs_dir);
+	sprintf(d->dfs_dir_name, "ubi%d_%d", c->vi.ubi_num, c->vi.vol_id);
+	d->dfs_dir = debugfs_create_dir(d->dfs_dir_name, dfs_rootdir);
+	if (IS_ERR(d->dfs_dir)) {
+		err = PTR_ERR(d->dfs_dir);
 		ubifs_err("cannot create \"%s\" debugfs directory, error %d\n",
-			  d->debugfs_dir_name, err);
+			  d->dfs_dir_name, err);
 		goto out;
 	}
 
 	fname = "dump_lprops";
-	dent = debugfs_create_file(fname, S_IWUGO, d->debugfs_dir, c,
-				   &debugfs_fops);
+	dent = debugfs_create_file(fname, S_IWUGO, d->dfs_dir, c, &dfs_fops);
 	if (IS_ERR(dent))
 		goto out_remove;
-	d->dump_lprops = dent;
+	d->dfs_dump_lprops = dent;
 
 	fname = "dump_budg";
-	dent = debugfs_create_file(fname, S_IWUGO, d->debugfs_dir, c,
-				   &debugfs_fops);
+	dent = debugfs_create_file(fname, S_IWUGO, d->dfs_dir, c, &dfs_fops);
 	if (IS_ERR(dent))
 		goto out_remove;
-	d->dump_budg = dent;
+	d->dfs_dump_budg = dent;
 
 	fname = "dump_tnc";
-	dent = debugfs_create_file(fname, S_IWUGO, d->debugfs_dir, c,
-				   &debugfs_fops);
+	dent = debugfs_create_file(fname, S_IWUGO, d->dfs_dir, c, &dfs_fops);
 	if (IS_ERR(dent))
 		goto out_remove;
-	d->dump_tnc = dent;
+	d->dfs_dump_tnc = dent;
 
 	return 0;
 
@@ -2531,7 +2585,7 @@ out_remove:
 	err = PTR_ERR(dent);
 	ubifs_err("cannot create \"%s\" debugfs directory, error %d\n",
 		  fname, err);
-	debugfs_remove_recursive(d->debugfs_dir);
+	debugfs_remove_recursive(d->dfs_dir);
 out:
 	return err;
 }
@@ -2542,7 +2596,7 @@ out:
  */
 void dbg_debugfs_exit_fs(struct ubifs_info *c)
 {
-	debugfs_remove_recursive(c->dbg->debugfs_dir);
+	debugfs_remove_recursive(c->dbg->dfs_dir);
 }
 
 #endif /* CONFIG_UBIFS_FS_DEBUG */
diff --git a/fs/ubifs/debug.h b/fs/ubifs/debug.h
index 9820d6999f7..c1cd73b2e06 100644
--- a/fs/ubifs/debug.h
+++ b/fs/ubifs/debug.h
@@ -41,15 +41,17 @@
  * @chk_lpt_wastage: used by LPT tree size checker
  * @chk_lpt_lebs: used by LPT tree size checker
  * @new_nhead_offs: used by LPT tree size checker
- * @new_ihead_lnum: used by debugging to check ihead_lnum
- * @new_ihead_offs: used by debugging to check ihead_offs
+ * @new_ihead_lnum: used by debugging to check @c->ihead_lnum
+ * @new_ihead_offs: used by debugging to check @c->ihead_offs
  *
- * debugfs_dir_name: name of debugfs directory containing this file-system's
- *                   files
- * debugfs_dir: direntry object of the file-system debugfs directory
- * dump_lprops: "dump lprops" debugfs knob
- * dump_budg: "dump budgeting information" debugfs knob
- * dump_tnc: "dump TNC" debugfs knob
+ * @saved_lst: saved lprops statistics (used by 'dbg_save_space_info()')
+ * @saved_free: saved free space (used by 'dbg_save_space_info()')
+ *
+ * dfs_dir_name: name of debugfs directory containing this file-system's files
+ * dfs_dir: direntry object of the file-system debugfs directory
+ * dfs_dump_lprops: "dump lprops" debugfs knob
+ * dfs_dump_budg: "dump budgeting information" debugfs knob
+ * dfs_dump_tnc: "dump TNC" debugfs knob
  */
 struct ubifs_debug_info {
 	void *buf;
@@ -69,11 +71,14 @@ struct ubifs_debug_info {
 	int new_ihead_lnum;
 	int new_ihead_offs;
 
-	char debugfs_dir_name[100];
-	struct dentry *debugfs_dir;
-	struct dentry *dump_lprops;
-	struct dentry *dump_budg;
-	struct dentry *dump_tnc;
+	struct ubifs_lp_stats saved_lst;
+	long long saved_free;
+
+	char dfs_dir_name[100];
+	struct dentry *dfs_dir;
+	struct dentry *dfs_dump_lprops;
+	struct dentry *dfs_dump_budg;
+	struct dentry *dfs_dump_tnc;
 };
 
 #define ubifs_assert(expr) do {                                                \
@@ -297,7 +302,8 @@ int dbg_walk_index(struct ubifs_info *c, dbg_leaf_callback leaf_cb,
 		   dbg_znode_callback znode_cb, void *priv);
 
 /* Checking functions */
-
+void dbg_save_space_info(struct ubifs_info *c);
+int dbg_check_space_info(struct ubifs_info *c);
 int dbg_check_lprops(struct ubifs_info *c);
 int dbg_old_index_check_init(struct ubifs_info *c, struct ubifs_zbranch *zroot);
 int dbg_check_old_index(struct ubifs_info *c, struct ubifs_zbranch *zroot);
@@ -439,6 +445,8 @@ void dbg_debugfs_exit_fs(struct ubifs_info *c);
 
 #define dbg_walk_index(c, leaf_cb, znode_cb, priv) 0
 #define dbg_old_index_check_init(c, zroot)         0
+#define dbg_save_space_info(c)                     ({})
+#define dbg_check_space_info(c)                    0
 #define dbg_check_old_index(c, zroot)              0
 #define dbg_check_cats(c)                          0
 #define dbg_check_ltab(c)                          0
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index f448ab1f9c3..f55d523c52b 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -482,30 +482,29 @@ static int ubifs_dir_release(struct inode *dir, struct file *file)
 }
 
 /**
- * lock_2_inodes - lock two UBIFS inodes.
+ * lock_2_inodes - a wrapper for locking two UBIFS inodes.
  * @inode1: first inode
  * @inode2: second inode
+ *
+ * We do not implement any tricks to guarantee strict lock ordering, because
+ * VFS has already done it for us on the @i_mutex. So this is just a simple
+ * wrapper function.
  */
 static void lock_2_inodes(struct inode *inode1, struct inode *inode2)
 {
-	if (inode1->i_ino < inode2->i_ino) {
-		mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_2);
-		mutex_lock_nested(&ubifs_inode(inode2)->ui_mutex, WB_MUTEX_3);
-	} else {
-		mutex_lock_nested(&ubifs_inode(inode2)->ui_mutex, WB_MUTEX_2);
-		mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_3);
-	}
+	mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_1);
+	mutex_lock_nested(&ubifs_inode(inode2)->ui_mutex, WB_MUTEX_2);
 }
 
 /**
- * unlock_2_inodes - unlock two UBIFS inodes inodes.
+ * unlock_2_inodes - a wrapper for unlocking two UBIFS inodes.
  * @inode1: first inode
  * @inode2: second inode
  */
 static void unlock_2_inodes(struct inode *inode1, struct inode *inode2)
 {
-	mutex_unlock(&ubifs_inode(inode1)->ui_mutex);
 	mutex_unlock(&ubifs_inode(inode2)->ui_mutex);
+	mutex_unlock(&ubifs_inode(inode1)->ui_mutex);
 }
 
 static int ubifs_link(struct dentry *old_dentry, struct inode *dir,
@@ -527,6 +526,8 @@ static int ubifs_link(struct dentry *old_dentry, struct inode *dir,
 	dbg_gen("dent '%.*s' to ino %lu (nlink %d) in dir ino %lu",
 		dentry->d_name.len, dentry->d_name.name, inode->i_ino,
 		inode->i_nlink, dir->i_ino);
+	ubifs_assert(mutex_is_locked(&dir->i_mutex));
+	ubifs_assert(mutex_is_locked(&inode->i_mutex));
 	err = dbg_check_synced_i_size(inode);
 	if (err)
 		return err;
@@ -580,6 +581,8 @@ static int ubifs_unlink(struct inode *dir, struct dentry *dentry)
 	dbg_gen("dent '%.*s' from ino %lu (nlink %d) in dir ino %lu",
 		dentry->d_name.len, dentry->d_name.name, inode->i_ino,
 		inode->i_nlink, dir->i_ino);
+	ubifs_assert(mutex_is_locked(&dir->i_mutex));
+	ubifs_assert(mutex_is_locked(&inode->i_mutex));
 	err = dbg_check_synced_i_size(inode);
 	if (err)
 		return err;
@@ -667,7 +670,8 @@ static int ubifs_rmdir(struct inode *dir, struct dentry *dentry)
 
 	dbg_gen("directory '%.*s', ino %lu in dir ino %lu", dentry->d_name.len,
 		dentry->d_name.name, inode->i_ino, dir->i_ino);
-
+	ubifs_assert(mutex_is_locked(&dir->i_mutex));
+	ubifs_assert(mutex_is_locked(&inode->i_mutex));
 	err = check_dir_empty(c, dentry->d_inode);
 	if (err)
 		return err;
@@ -922,59 +926,30 @@ out_budg:
 }
 
 /**
- * lock_3_inodes - lock three UBIFS inodes for rename.
+ * lock_3_inodes - a wrapper for locking three UBIFS inodes.
  * @inode1: first inode
  * @inode2: second inode
  * @inode3: third inode
  *
- * For 'ubifs_rename()', @inode1 may be the same as @inode2 whereas @inode3 may
- * be null.
+ * This function is used for 'ubifs_rename()' and @inode1 may be the same as
+ * @inode2 whereas @inode3 may be %NULL.
+ *
+ * We do not implement any tricks to guarantee strict lock ordering, because
+ * VFS has already done it for us on the @i_mutex. So this is just a simple
+ * wrapper function.
  */
 static void lock_3_inodes(struct inode *inode1, struct inode *inode2,
 			  struct inode *inode3)
 {
-	struct inode *i1, *i2, *i3;
-
-	if (!inode3) {
-		if (inode1 != inode2) {
-			lock_2_inodes(inode1, inode2);
-			return;
-		}
-		mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_1);
-		return;
-	}
-
-	if (inode1 == inode2) {
-		lock_2_inodes(inode1, inode3);
-		return;
-	}
-
-	/* 3 different inodes */
-	if (inode1 < inode2) {
-		i3 = inode2;
-		if (inode1 < inode3) {
-			i1 = inode1;
-			i2 = inode3;
-		} else {
-			i1 = inode3;
-			i2 = inode1;
-		}
-	} else {
-		i3 = inode1;
-		if (inode2 < inode3) {
-			i1 = inode2;
-			i2 = inode3;
-		} else {
-			i1 = inode3;
-			i2 = inode2;
-		}
-	}
-	mutex_lock_nested(&ubifs_inode(i1)->ui_mutex, WB_MUTEX_1);
-	lock_2_inodes(i2, i3);
+	mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_1);
+	if (inode2 != inode1)
+		mutex_lock_nested(&ubifs_inode(inode2)->ui_mutex, WB_MUTEX_2);
+	if (inode3)
+		mutex_lock_nested(&ubifs_inode(inode3)->ui_mutex, WB_MUTEX_3);
 }
 
 /**
- * unlock_3_inodes - unlock three UBIFS inodes for rename.
+ * unlock_3_inodes - a wrapper for unlocking three UBIFS inodes for rename.
  * @inode1: first inode
  * @inode2: second inode
  * @inode3: third inode
@@ -982,11 +957,11 @@ static void lock_3_inodes(struct inode *inode1, struct inode *inode2,
 static void unlock_3_inodes(struct inode *inode1, struct inode *inode2,
 			    struct inode *inode3)
 {
-	mutex_unlock(&ubifs_inode(inode1)->ui_mutex);
-	if (inode1 != inode2)
-		mutex_unlock(&ubifs_inode(inode2)->ui_mutex);
 	if (inode3)
 		mutex_unlock(&ubifs_inode(inode3)->ui_mutex);
+	if (inode1 != inode2)
+		mutex_unlock(&ubifs_inode(inode2)->ui_mutex);
+	mutex_unlock(&ubifs_inode(inode1)->ui_mutex);
 }
 
 static int ubifs_rename(struct inode *old_dir, struct dentry *old_dentry,
@@ -1020,6 +995,11 @@ static int ubifs_rename(struct inode *old_dir, struct dentry *old_dentry,
 		"dir ino %lu", old_dentry->d_name.len, old_dentry->d_name.name,
 		old_inode->i_ino, old_dir->i_ino, new_dentry->d_name.len,
 		new_dentry->d_name.name, new_dir->i_ino);
+	ubifs_assert(mutex_is_locked(&old_dir->i_mutex));
+	ubifs_assert(mutex_is_locked(&new_dir->i_mutex));
+	if (unlink)
+		ubifs_assert(mutex_is_locked(&new_inode->i_mutex));
+
 
 	if (unlink && is_dir) {
 		err = check_dir_empty(c, new_inode);
@@ -1199,7 +1179,7 @@ int ubifs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 	return 0;
 }
 
-struct inode_operations ubifs_dir_inode_operations = {
+const struct inode_operations ubifs_dir_inode_operations = {
 	.lookup      = ubifs_lookup,
 	.create      = ubifs_create,
 	.link        = ubifs_link,
@@ -1219,7 +1199,7 @@ struct inode_operations ubifs_dir_inode_operations = {
 #endif
 };
 
-struct file_operations ubifs_dir_operations = {
+const struct file_operations ubifs_dir_operations = {
 	.llseek         = ubifs_dir_llseek,
 	.release        = ubifs_dir_release,
 	.read           = generic_read_dir,
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index bf37374567f..93b6de51f26 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -432,7 +432,6 @@ static int ubifs_write_begin(struct file *file, struct address_space *mapping,
 	int uninitialized_var(err), appending = !!(pos + len > inode->i_size);
 	struct page *page;
 
-
 	ubifs_assert(ubifs_inode(inode)->ui_size == inode->i_size);
 
 	if (unlikely(c->ro_media))
@@ -1541,7 +1540,7 @@ static int ubifs_file_mmap(struct file *file, struct vm_area_struct *vma)
 	return 0;
 }
 
-struct address_space_operations ubifs_file_address_operations = {
+const struct address_space_operations ubifs_file_address_operations = {
 	.readpage       = ubifs_readpage,
 	.writepage      = ubifs_writepage,
 	.write_begin    = ubifs_write_begin,
@@ -1551,7 +1550,7 @@ struct address_space_operations ubifs_file_address_operations = {
 	.releasepage    = ubifs_releasepage,
 };
 
-struct inode_operations ubifs_file_inode_operations = {
+const struct inode_operations ubifs_file_inode_operations = {
 	.setattr     = ubifs_setattr,
 	.getattr     = ubifs_getattr,
 #ifdef CONFIG_UBIFS_FS_XATTR
@@ -1562,14 +1561,14 @@ struct inode_operations ubifs_file_inode_operations = {
 #endif
 };
 
-struct inode_operations ubifs_symlink_inode_operations = {
+const struct inode_operations ubifs_symlink_inode_operations = {
 	.readlink    = generic_readlink,
 	.follow_link = ubifs_follow_link,
 	.setattr     = ubifs_setattr,
 	.getattr     = ubifs_getattr,
 };
 
-struct file_operations ubifs_file_operations = {
+const struct file_operations ubifs_file_operations = {
 	.llseek         = generic_file_llseek,
 	.read           = do_sync_read,
 	.write          = do_sync_write,
diff --git a/fs/ubifs/gc.c b/fs/ubifs/gc.c
index 9832f9abe28..a711d33b3d3 100644
--- a/fs/ubifs/gc.c
+++ b/fs/ubifs/gc.c
@@ -31,6 +31,26 @@
  * to be reused. Garbage collection will cause the number of dirty index nodes
  * to grow, however sufficient space is reserved for the index to ensure the
  * commit will never run out of space.
+ *
+ * Notes about dead watermark. At current UBIFS implementation we assume that
+ * LEBs which have less than @c->dead_wm bytes of free + dirty space are full
+ * and not worth garbage-collecting. The dead watermark is one min. I/O unit
+ * size, or min. UBIFS node size, depending on what is greater. Indeed, UBIFS
+ * Garbage Collector has to synchronize the GC head's write buffer before
+ * returning, so this is about wasting one min. I/O unit. However, UBIFS GC can
+ * actually reclaim even very small pieces of dirty space by garbage collecting
+ * enough dirty LEBs, but we do not bother doing this at this implementation.
+ *
+ * Notes about dark watermark. The results of GC work depends on how big are
+ * the UBIFS nodes GC deals with. Large nodes make GC waste more space. Indeed,
+ * if GC move data from LEB A to LEB B and nodes in LEB A are large, GC would
+ * have to waste large pieces of free space at the end of LEB B, because nodes
+ * from LEB A would not fit. And the worst situation is when all nodes are of
+ * maximum size. So dark watermark is the amount of free + dirty space in LEB
+ * which are guaranteed to be reclaimable. If LEB has less space, the GC migh
+ * be unable to reclaim it. So, LEBs with free + dirty greater than dark
+ * watermark are "good" LEBs from GC's point of few. The other LEBs are not so
+ * good, and GC takes extra care when moving them.
  */
 
 #include <linux/pagemap.h>
@@ -381,7 +401,7 @@ int ubifs_garbage_collect_leb(struct ubifs_info *c, struct ubifs_lprops *lp)
 
 		/*
 		 * Don't release the LEB until after the next commit, because
-		 * it may contain date which is needed for recovery. So
+		 * it may contain data which is needed for recovery. So
 		 * although we freed this LEB, it will become usable only after
 		 * the commit.
 		 */
@@ -810,8 +830,9 @@ out:
  * ubifs_destroy_idx_gc - destroy idx_gc list.
  * @c: UBIFS file-system description object
  *
- * This function destroys the idx_gc list. It is called when unmounting or
- * remounting read-only so locks are not needed.
+ * This function destroys the @c->idx_gc list. It is called when unmounting
+ * so locks are not needed. Returns zero in case of success and a negative
+ * error code in case of failure.
  */
 void ubifs_destroy_idx_gc(struct ubifs_info *c)
 {
@@ -824,7 +845,6 @@ void ubifs_destroy_idx_gc(struct ubifs_info *c)
 		list_del(&idx_gc->list);
 		kfree(idx_gc);
 	}
-
 }
 
 /**
diff --git a/fs/ubifs/io.c b/fs/ubifs/io.c
index 01682713af6..e8e632a1dcd 100644
--- a/fs/ubifs/io.c
+++ b/fs/ubifs/io.c
@@ -29,7 +29,7 @@
  * would have been wasted for padding to the nearest minimal I/O unit boundary.
  * Instead, data first goes to the write-buffer and is flushed when the
  * buffer is full or when it is not used for some time (by timer). This is
- * similarto the mechanism is used by JFFS2.
+ * similar to the mechanism is used by JFFS2.
  *
  * Write-buffers are defined by 'struct ubifs_wbuf' objects and protected by
  * mutexes defined inside these objects. Since sometimes upper-level code
@@ -75,7 +75,7 @@ void ubifs_ro_mode(struct ubifs_info *c, int err)
  * @lnum: logical eraseblock number
  * @offs: offset within the logical eraseblock
  * @quiet: print no messages
- * @chk_crc: indicates whether to always check the CRC
+ * @must_chk_crc: indicates whether to always check the CRC
  *
  * This function checks node magic number and CRC checksum. This function also
  * validates node length to prevent UBIFS from becoming crazy when an attacker
@@ -83,11 +83,17 @@ void ubifs_ro_mode(struct ubifs_info *c, int err)
  * node length in the common header could cause UBIFS to read memory outside of
  * allocated buffer when checking the CRC checksum.
  *
- * This function returns zero in case of success %-EUCLEAN in case of bad CRC
- * or magic.
+ * This function may skip data nodes CRC checking if @c->no_chk_data_crc is
+ * true, which is controlled by corresponding UBIFS mount option. However, if
+ * @must_chk_crc is true, then @c->no_chk_data_crc is ignored and CRC is
+ * checked. Similarly, if @c->always_chk_crc is true, @c->no_chk_data_crc is
+ * ignored and CRC is checked.
+ *
+ * This function returns zero in case of success and %-EUCLEAN in case of bad
+ * CRC or magic.
  */
 int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum,
-		     int offs, int quiet, int chk_crc)
+		     int offs, int quiet, int must_chk_crc)
 {
 	int err = -EINVAL, type, node_len;
 	uint32_t crc, node_crc, magic;
@@ -123,9 +129,9 @@ int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum,
 		   node_len > c->ranges[type].max_len)
 		goto out_len;
 
-	if (!chk_crc && type == UBIFS_DATA_NODE && !c->always_chk_crc)
-		if (c->no_chk_data_crc)
-			return 0;
+	if (!must_chk_crc && type == UBIFS_DATA_NODE && !c->always_chk_crc &&
+	     c->no_chk_data_crc)
+		return 0;
 
 	crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
 	node_crc = le32_to_cpu(ch->crc);
diff --git a/fs/ubifs/journal.c b/fs/ubifs/journal.c
index 9b7c54e0cd2..a11ca0958a2 100644
--- a/fs/ubifs/journal.c
+++ b/fs/ubifs/journal.c
@@ -208,7 +208,7 @@ again:
 	offs = 0;
 
 out:
-	err = ubifs_wbuf_seek_nolock(wbuf, lnum, offs, UBI_SHORTTERM);
+	err = ubifs_wbuf_seek_nolock(wbuf, lnum, offs, wbuf->dtype);
 	if (err)
 		goto out_unlock;
 
diff --git a/fs/ubifs/lprops.c b/fs/ubifs/lprops.c
index dfd2bcece27..4cdd284dea5 100644
--- a/fs/ubifs/lprops.c
+++ b/fs/ubifs/lprops.c
@@ -635,10 +635,10 @@ const struct ubifs_lprops *ubifs_change_lp(struct ubifs_info *c,
  * @c: UBIFS file-system description object
  * @st: return statistics
  */
-void ubifs_get_lp_stats(struct ubifs_info *c, struct ubifs_lp_stats *st)
+void ubifs_get_lp_stats(struct ubifs_info *c, struct ubifs_lp_stats *lst)
 {
 	spin_lock(&c->space_lock);
-	memcpy(st, &c->lst, sizeof(struct ubifs_lp_stats));
+	memcpy(lst, &c->lst, sizeof(struct ubifs_lp_stats));
 	spin_unlock(&c->space_lock);
 }
 
@@ -678,6 +678,9 @@ int ubifs_change_one_lp(struct ubifs_info *c, int lnum, int free, int dirty,
 
 out:
 	ubifs_release_lprops(c);
+	if (err)
+		ubifs_err("cannot change properties of LEB %d, error %d",
+			  lnum, err);
 	return err;
 }
 
@@ -714,6 +717,9 @@ int ubifs_update_one_lp(struct ubifs_info *c, int lnum, int free, int dirty,
 
 out:
 	ubifs_release_lprops(c);
+	if (err)
+		ubifs_err("cannot update properties of LEB %d, error %d",
+			  lnum, err);
 	return err;
 }
 
@@ -737,6 +743,8 @@ int ubifs_read_one_lp(struct ubifs_info *c, int lnum, struct ubifs_lprops *lp)
 	lpp = ubifs_lpt_lookup(c, lnum);
 	if (IS_ERR(lpp)) {
 		err = PTR_ERR(lpp);
+		ubifs_err("cannot read properties of LEB %d, error %d",
+			  lnum, err);
 		goto out;
 	}
 
diff --git a/fs/ubifs/lpt_commit.c b/fs/ubifs/lpt_commit.c
index 96ca9570717..3216a1f277f 100644
--- a/fs/ubifs/lpt_commit.c
+++ b/fs/ubifs/lpt_commit.c
@@ -556,23 +556,23 @@ no_space:
 }
 
 /**
- * next_pnode - find next pnode.
+ * next_pnode_to_dirty - find next pnode to dirty.
  * @c: UBIFS file-system description object
  * @pnode: pnode
  *
- * This function returns the next pnode or %NULL if there are no more pnodes.
+ * This function returns the next pnode to dirty or %NULL if there are no more
+ * pnodes.  Note that pnodes that have never been written (lnum == 0) are
+ * skipped.
  */
-static struct ubifs_pnode *next_pnode(struct ubifs_info *c,
-				      struct ubifs_pnode *pnode)
+static struct ubifs_pnode *next_pnode_to_dirty(struct ubifs_info *c,
+					       struct ubifs_pnode *pnode)
 {
 	struct ubifs_nnode *nnode;
 	int iip;
 
 	/* Try to go right */
 	nnode = pnode->parent;
-	iip = pnode->iip + 1;
-	if (iip < UBIFS_LPT_FANOUT) {
-		/* We assume here that LEB zero is never an LPT LEB */
+	for (iip = pnode->iip + 1; iip < UBIFS_LPT_FANOUT; iip++) {
 		if (nnode->nbranch[iip].lnum)
 			return ubifs_get_pnode(c, nnode, iip);
 	}
@@ -583,8 +583,11 @@ static struct ubifs_pnode *next_pnode(struct ubifs_info *c,
 		nnode = nnode->parent;
 		if (!nnode)
 			return NULL;
-		/* We assume here that LEB zero is never an LPT LEB */
-	} while (iip >= UBIFS_LPT_FANOUT || !nnode->nbranch[iip].lnum);
+		for (; iip < UBIFS_LPT_FANOUT; iip++) {
+			if (nnode->nbranch[iip].lnum)
+				break;
+		}
+       } while (iip >= UBIFS_LPT_FANOUT);
 
 	/* Go right */
 	nnode = ubifs_get_nnode(c, nnode, iip);
@@ -593,12 +596,29 @@ static struct ubifs_pnode *next_pnode(struct ubifs_info *c,
 
 	/* Go down to level 1 */
 	while (nnode->level > 1) {
-		nnode = ubifs_get_nnode(c, nnode, 0);
+		for (iip = 0; iip < UBIFS_LPT_FANOUT; iip++) {
+			if (nnode->nbranch[iip].lnum)
+				break;
+		}
+		if (iip >= UBIFS_LPT_FANOUT) {
+			/*
+			 * Should not happen, but we need to keep going
+			 * if it does.
+			 */
+			iip = 0;
+		}
+		nnode = ubifs_get_nnode(c, nnode, iip);
 		if (IS_ERR(nnode))
 			return (void *)nnode;
 	}
 
-	return ubifs_get_pnode(c, nnode, 0);
+	for (iip = 0; iip < UBIFS_LPT_FANOUT; iip++)
+		if (nnode->nbranch[iip].lnum)
+			break;
+	if (iip >= UBIFS_LPT_FANOUT)
+		/* Should not happen, but we need to keep going if it does */
+		iip = 0;
+	return ubifs_get_pnode(c, nnode, iip);
 }
 
 /**
@@ -688,7 +708,7 @@ static int make_tree_dirty(struct ubifs_info *c)
 	pnode = pnode_lookup(c, 0);
 	while (pnode) {
 		do_make_pnode_dirty(c, pnode);
-		pnode = next_pnode(c, pnode);
+		pnode = next_pnode_to_dirty(c, pnode);
 		if (IS_ERR(pnode))
 			return PTR_ERR(pnode);
 	}
diff --git a/fs/ubifs/master.c b/fs/ubifs/master.c
index 71d5493bf56..a88f33801b9 100644
--- a/fs/ubifs/master.c
+++ b/fs/ubifs/master.c
@@ -354,7 +354,7 @@ int ubifs_write_master(struct ubifs_info *c)
 	int err, lnum, offs, len;
 
 	if (c->ro_media)
-		return -EINVAL;
+		return -EROFS;
 
 	lnum = UBIFS_MST_LNUM;
 	offs = c->mst_offs + c->mst_node_alsz;
diff --git a/fs/ubifs/orphan.c b/fs/ubifs/orphan.c
index 9e6f403f170..152a7b34a14 100644
--- a/fs/ubifs/orphan.c
+++ b/fs/ubifs/orphan.c
@@ -46,7 +46,7 @@
  * Orphans are accumulated in a rb-tree. When an inode's link count drops to
  * zero, the inode number is added to the rb-tree. It is removed from the tree
  * when the inode is deleted.  Any new orphans that are in the orphan tree when
- * the commit is run, are written to the orphan area in 1 or more orph nodes.
+ * the commit is run, are written to the orphan area in 1 or more orphan nodes.
  * If the orphan area is full, it is consolidated to make space.  There is
  * always enough space because validation prevents the user from creating more
  * than the maximum number of orphans allowed.
@@ -231,7 +231,7 @@ static int tot_avail_orphs(struct ubifs_info *c)
 }
 
 /**
- * do_write_orph_node - write a node
+ * do_write_orph_node - write a node to the orphan head.
  * @c: UBIFS file-system description object
  * @len: length of node
  * @atomic: write atomically
@@ -264,11 +264,11 @@ static int do_write_orph_node(struct ubifs_info *c, int len, int atomic)
 }
 
 /**
- * write_orph_node - write an orph node
+ * write_orph_node - write an orphan node.
  * @c: UBIFS file-system description object
  * @atomic: write atomically
  *
- * This function builds an orph node from the cnext list and writes it to the
+ * This function builds an orphan node from the cnext list and writes it to the
  * orphan head. On success, %0 is returned, otherwise a negative error code
  * is returned.
  */
@@ -326,11 +326,11 @@ static int write_orph_node(struct ubifs_info *c, int atomic)
 }
 
 /**
- * write_orph_nodes - write orph nodes until there are no more to commit
+ * write_orph_nodes - write orphan nodes until there are no more to commit.
  * @c: UBIFS file-system description object
  * @atomic: write atomically
  *
- * This function writes orph nodes for all the orphans to commit. On success,
+ * This function writes orphan nodes for all the orphans to commit. On success,
  * %0 is returned, otherwise a negative error code is returned.
  */
 static int write_orph_nodes(struct ubifs_info *c, int atomic)
@@ -478,14 +478,14 @@ int ubifs_orphan_end_commit(struct ubifs_info *c)
 }
 
 /**
- * clear_orphans - erase all LEBs used for orphans.
+ * ubifs_clear_orphans - erase all LEBs used for orphans.
  * @c: UBIFS file-system description object
  *
  * If recovery is not required, then the orphans from the previous session
  * are not needed. This function locates the LEBs used to record
  * orphans, and un-maps them.
  */
-static int clear_orphans(struct ubifs_info *c)
+int ubifs_clear_orphans(struct ubifs_info *c)
 {
 	int lnum, err;
 
@@ -547,9 +547,9 @@ static int insert_dead_orphan(struct ubifs_info *c, ino_t inum)
  * do_kill_orphans - remove orphan inodes from the index.
  * @c: UBIFS file-system description object
  * @sleb: scanned LEB
- * @last_cmt_no: cmt_no of last orph node read is passed and returned here
+ * @last_cmt_no: cmt_no of last orphan node read is passed and returned here
  * @outofdate: whether the LEB is out of date is returned here
- * @last_flagged: whether the end orph node is encountered
+ * @last_flagged: whether the end orphan node is encountered
  *
  * This function is a helper to the 'kill_orphans()' function. It goes through
  * every orphan node in a LEB and for every inode number recorded, removes
@@ -580,8 +580,8 @@ static int do_kill_orphans(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
 		/*
 		 * The commit number on the master node may be less, because
 		 * of a failed commit. If there are several failed commits in a
-		 * row, the commit number written on orph nodes will continue to
-		 * increase (because the commit number is adjusted here) even
+		 * row, the commit number written on orphan nodes will continue
+		 * to increase (because the commit number is adjusted here) even
 		 * though the commit number on the master node stays the same
 		 * because the master node has not been re-written.
 		 */
@@ -589,9 +589,9 @@ static int do_kill_orphans(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
 			c->cmt_no = cmt_no;
 		if (cmt_no < *last_cmt_no && *last_flagged) {
 			/*
-			 * The last orph node had a higher commit number and was
-			 * flagged as the last written for that commit number.
-			 * That makes this orph node, out of date.
+			 * The last orphan node had a higher commit number and
+			 * was flagged as the last written for that commit
+			 * number. That makes this orphan node, out of date.
 			 */
 			if (!first) {
 				ubifs_err("out of order commit number %llu in "
@@ -658,10 +658,10 @@ static int kill_orphans(struct ubifs_info *c)
 	/*
 	 * Orph nodes always start at c->orph_first and are written to each
 	 * successive LEB in turn. Generally unused LEBs will have been unmapped
-	 * but may contain out of date orph nodes if the unmap didn't go
-	 * through. In addition, the last orph node written for each commit is
+	 * but may contain out of date orphan nodes if the unmap didn't go
+	 * through. In addition, the last orphan node written for each commit is
 	 * marked (top bit of orph->cmt_no is set to 1). It is possible that
-	 * there are orph nodes from the next commit (i.e. the commit did not
+	 * there are orphan nodes from the next commit (i.e. the commit did not
 	 * complete successfully). In that case, no orphans will have been lost
 	 * due to the way that orphans are written, and any orphans added will
 	 * be valid orphans anyway and so can be deleted.
@@ -718,7 +718,7 @@ int ubifs_mount_orphans(struct ubifs_info *c, int unclean, int read_only)
 	if (unclean)
 		err = kill_orphans(c);
 	else if (!read_only)
-		err = clear_orphans(c);
+		err = ubifs_clear_orphans(c);
 
 	return err;
 }
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 89556ee7251..1182b66a549 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -397,6 +397,7 @@ static int ubifs_statfs(struct dentry *dentry, struct kstatfs *buf)
 	buf->f_namelen = UBIFS_MAX_NLEN;
 	buf->f_fsid.val[0] = le32_to_cpu(uuid[0]) ^ le32_to_cpu(uuid[2]);
 	buf->f_fsid.val[1] = le32_to_cpu(uuid[1]) ^ le32_to_cpu(uuid[3]);
+	ubifs_assert(buf->f_bfree <= c->block_cnt);
 	return 0;
 }
 
@@ -432,33 +433,24 @@ static int ubifs_sync_fs(struct super_block *sb, int wait)
 	int i, err;
 	struct ubifs_info *c = sb->s_fs_info;
 	struct writeback_control wbc = {
-		.sync_mode   = wait ? WB_SYNC_ALL : WB_SYNC_NONE,
+		.sync_mode   = WB_SYNC_ALL,
 		.range_start = 0,
 		.range_end   = LLONG_MAX,
 		.nr_to_write = LONG_MAX,
 	};
 
 	/*
-	 * Note by akpm about WB_SYNC_NONE used above: zero @wait is just an
-	 * advisory thing to help the file system shove lots of data into the
-	 * queues. If some gets missed then it'll be picked up on the second
+	 * Zero @wait is just an advisory thing to help the file system shove
+	 * lots of data into the queues, and there will be the second
 	 * '->sync_fs()' call, with non-zero @wait.
 	 */
+	if (!wait)
+		return 0;
 
 	if (sb->s_flags & MS_RDONLY)
 		return 0;
 
 	/*
-	 * Synchronize write buffers, because 'ubifs_run_commit()' does not
-	 * do this if it waits for an already running commit.
-	 */
-	for (i = 0; i < c->jhead_cnt; i++) {
-		err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
-		if (err)
-			return err;
-	}
-
-	/*
 	 * VFS calls '->sync_fs()' before synchronizing all dirty inodes and
 	 * pages, so synchronize them first, then commit the journal. Strictly
 	 * speaking, it is not necessary to commit the journal here,
@@ -469,6 +461,16 @@ static int ubifs_sync_fs(struct super_block *sb, int wait)
 	 */
 	generic_sync_sb_inodes(sb, &wbc);
 
+	/*
+	 * Synchronize write buffers, because 'ubifs_run_commit()' does not
+	 * do this if it waits for an already running commit.
+	 */
+	for (i = 0; i < c->jhead_cnt; i++) {
+		err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
+		if (err)
+			return err;
+	}
+
 	err = ubifs_run_commit(c);
 	if (err)
 		return err;
@@ -572,15 +574,8 @@ static int init_constants_early(struct ubifs_info *c)
 	c->ranges[UBIFS_IDX_NODE].max_len = INT_MAX;
 
 	/*
-	 * Initialize dead and dark LEB space watermarks.
-	 *
-	 * Dead space is the space which cannot be used. Its watermark is
-	 * equivalent to min. I/O unit or minimum node size if it is greater
-	 * then min. I/O unit.
-	 *
-	 * Dark space is the space which might be used, or might not, depending
-	 * on which node should be written to the LEB. Its watermark is
-	 * equivalent to maximum UBIFS node size.
+	 * Initialize dead and dark LEB space watermarks. See gc.c for comments
+	 * about these values.
 	 */
 	c->dead_wm = ALIGN(MIN_WRITE_SZ, c->min_io_size);
 	c->dark_wm = ALIGN(UBIFS_MAX_NODE_SZ, c->min_io_size);
@@ -741,12 +736,12 @@ static void init_constants_master(struct ubifs_info *c)
  * take_gc_lnum - reserve GC LEB.
  * @c: UBIFS file-system description object
  *
- * This function ensures that the LEB reserved for garbage collection is
- * unmapped and is marked as "taken" in lprops. We also have to set free space
- * to LEB size and dirty space to zero, because lprops may contain out-of-date
- * information if the file-system was un-mounted before it has been committed.
- * This function returns zero in case of success and a negative error code in
- * case of failure.
+ * This function ensures that the LEB reserved for garbage collection is marked
+ * as "taken" in lprops. We also have to set free space to LEB size and dirty
+ * space to zero, because lprops may contain out-of-date information if the
+ * file-system was un-mounted before it has been committed. This function
+ * returns zero in case of success and a negative error code in case of
+ * failure.
  */
 static int take_gc_lnum(struct ubifs_info *c)
 {
@@ -757,10 +752,6 @@ static int take_gc_lnum(struct ubifs_info *c)
 		return -EINVAL;
 	}
 
-	err = ubifs_leb_unmap(c, c->gc_lnum);
-	if (err)
-		return err;
-
 	/* And we have to tell lprops that this LEB is taken */
 	err = ubifs_change_one_lp(c, c->gc_lnum, c->leb_size, 0,
 				  LPROPS_TAKEN, 0, 0);
@@ -966,13 +957,16 @@ static int ubifs_parse_options(struct ubifs_info *c, char *options,
 
 		token = match_token(p, tokens, args);
 		switch (token) {
+		/*
+		 * %Opt_fast_unmount and %Opt_norm_unmount options are ignored.
+		 * We accepte them in order to be backware-compatible. But this
+		 * should be removed at some point.
+		 */
 		case Opt_fast_unmount:
 			c->mount_opts.unmount_mode = 2;
-			c->fast_unmount = 1;
 			break;
 		case Opt_norm_unmount:
 			c->mount_opts.unmount_mode = 1;
-			c->fast_unmount = 0;
 			break;
 		case Opt_bulk_read:
 			c->mount_opts.bulk_read = 2;
@@ -1094,12 +1088,7 @@ static int check_free_space(struct ubifs_info *c)
 		ubifs_err("insufficient free space to mount in read/write mode");
 		dbg_dump_budg(c);
 		dbg_dump_lprops(c);
-		/*
-		 * We return %-EINVAL instead of %-ENOSPC because it seems to
-		 * be the closest error code mentioned in the mount function
-		 * documentation.
-		 */
-		return -EINVAL;
+		return -ENOSPC;
 	}
 	return 0;
 }
@@ -1286,10 +1275,19 @@ static int mount_ubifs(struct ubifs_info *c)
 			if (err)
 				goto out_orphans;
 			err = ubifs_rcvry_gc_commit(c);
-		} else
+		} else {
 			err = take_gc_lnum(c);
-		if (err)
-			goto out_orphans;
+			if (err)
+				goto out_orphans;
+
+			/*
+			 * GC LEB may contain garbage if there was an unclean
+			 * reboot, and it should be un-mapped.
+			 */
+			err = ubifs_leb_unmap(c, c->gc_lnum);
+			if (err)
+				return err;
+		}
 
 		err = dbg_check_lprops(c);
 		if (err)
@@ -1298,6 +1296,16 @@ static int mount_ubifs(struct ubifs_info *c)
 		err = ubifs_recover_size(c);
 		if (err)
 			goto out_orphans;
+	} else {
+		/*
+		 * Even if we mount read-only, we have to set space in GC LEB
+		 * to proper value because this affects UBIFS free space
+		 * reporting. We do not want to have a situation when
+		 * re-mounting from R/O to R/W changes amount of free space.
+		 */
+		err = take_gc_lnum(c);
+		if (err)
+			goto out_orphans;
 	}
 
 	spin_lock(&ubifs_infos_lock);
@@ -1310,14 +1318,17 @@ static int mount_ubifs(struct ubifs_info *c)
 		else {
 			c->need_recovery = 0;
 			ubifs_msg("recovery completed");
+			/* GC LEB has to be empty and taken at this point */
+			ubifs_assert(c->lst.taken_empty_lebs == 1);
 		}
-	}
+	} else
+		ubifs_assert(c->lst.taken_empty_lebs == 1);
 
-	err = dbg_debugfs_init_fs(c);
+	err = dbg_check_filesystem(c);
 	if (err)
 		goto out_infos;
 
-	err = dbg_check_filesystem(c);
+	err = dbg_debugfs_init_fs(c);
 	if (err)
 		goto out_infos;
 
@@ -1351,7 +1362,6 @@ static int mount_ubifs(struct ubifs_info *c)
 	       c->uuid[4], c->uuid[5], c->uuid[6], c->uuid[7],
 	       c->uuid[8], c->uuid[9], c->uuid[10], c->uuid[11],
 	       c->uuid[12], c->uuid[13], c->uuid[14], c->uuid[15]);
-	dbg_msg("fast unmount:        %d", c->fast_unmount);
 	dbg_msg("big_lpt              %d", c->big_lpt);
 	dbg_msg("log LEBs:            %d (%d - %d)",
 		c->log_lebs, UBIFS_LOG_LNUM, c->log_last);
@@ -1475,10 +1485,8 @@ static int ubifs_remount_rw(struct ubifs_info *c)
 {
 	int err, lnum;
 
-	if (c->ro_media)
-		return -EINVAL;
-
 	mutex_lock(&c->umount_mutex);
+	dbg_save_space_info(c);
 	c->remounting_rw = 1;
 	c->always_chk_crc = 1;
 
@@ -1514,6 +1522,12 @@ static int ubifs_remount_rw(struct ubifs_info *c)
 		err = ubifs_recover_inl_heads(c, c->sbuf);
 		if (err)
 			goto out;
+	} else {
+		/* A readonly mount is not allowed to have orphans */
+		ubifs_assert(c->tot_orphans == 0);
+		err = ubifs_clear_orphans(c);
+		if (err)
+			goto out;
 	}
 
 	if (!(c->mst_node->flags & cpu_to_le32(UBIFS_MST_DIRTY))) {
@@ -1569,7 +1583,7 @@ static int ubifs_remount_rw(struct ubifs_info *c)
 	if (c->need_recovery)
 		err = ubifs_rcvry_gc_commit(c);
 	else
-		err = take_gc_lnum(c);
+		err = ubifs_leb_unmap(c, c->gc_lnum);
 	if (err)
 		goto out;
 
@@ -1582,8 +1596,9 @@ static int ubifs_remount_rw(struct ubifs_info *c)
 	c->vfs_sb->s_flags &= ~MS_RDONLY;
 	c->remounting_rw = 0;
 	c->always_chk_crc = 0;
+	err = dbg_check_space_info(c);
 	mutex_unlock(&c->umount_mutex);
-	return 0;
+	return err;
 
 out:
 	vfree(c->orph_buf);
@@ -1603,43 +1618,18 @@ out:
 }
 
 /**
- * commit_on_unmount - commit the journal when un-mounting.
- * @c: UBIFS file-system description object
- *
- * This function is called during un-mounting and re-mounting, and it commits
- * the journal unless the "fast unmount" mode is enabled.
- */
-static void commit_on_unmount(struct ubifs_info *c)
-{
-	struct super_block *sb = c->vfs_sb;
-	long long bud_bytes;
-
-	/*
-	 * This function is called before the background thread is stopped, so
-	 * we may race with ongoing commit, which means we have to take
-	 * @c->bud_lock to access @c->bud_bytes.
-	 */
-	spin_lock(&c->buds_lock);
-	bud_bytes = c->bud_bytes;
-	spin_unlock(&c->buds_lock);
-
-	if (!c->fast_unmount && !(sb->s_flags & MS_RDONLY) && bud_bytes)
-		ubifs_run_commit(c);
-}
-
-/**
  * ubifs_remount_ro - re-mount in read-only mode.
  * @c: UBIFS file-system description object
  *
- * We rely on VFS to have stopped writing. Possibly the background thread could
- * be running a commit, however kthread_stop will wait in that case.
+ * We assume VFS has stopped writing. Possibly the background thread could be
+ * running a commit, however kthread_stop will wait in that case.
  */
 static void ubifs_remount_ro(struct ubifs_info *c)
 {
 	int i, err;
 
 	ubifs_assert(!c->need_recovery);
-	commit_on_unmount(c);
+	ubifs_assert(!(c->vfs_sb->s_flags & MS_RDONLY));
 
 	mutex_lock(&c->umount_mutex);
 	if (c->bgt) {
@@ -1647,27 +1637,29 @@ static void ubifs_remount_ro(struct ubifs_info *c)
 		c->bgt = NULL;
 	}
 
+	dbg_save_space_info(c);
+
 	for (i = 0; i < c->jhead_cnt; i++) {
 		ubifs_wbuf_sync(&c->jheads[i].wbuf);
 		del_timer_sync(&c->jheads[i].wbuf.timer);
 	}
 
-	if (!c->ro_media) {
-		c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
-		c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
-		c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
-		err = ubifs_write_master(c);
-		if (err)
-			ubifs_ro_mode(c, err);
-	}
+	c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
+	c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
+	c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
+	err = ubifs_write_master(c);
+	if (err)
+		ubifs_ro_mode(c, err);
 
-	ubifs_destroy_idx_gc(c);
 	free_wbufs(c);
 	vfree(c->orph_buf);
 	c->orph_buf = NULL;
 	vfree(c->ileb_buf);
 	c->ileb_buf = NULL;
 	ubifs_lpt_free(c, 1);
+	err = dbg_check_space_info(c);
+	if (err)
+		ubifs_ro_mode(c, err);
 	mutex_unlock(&c->umount_mutex);
 }
 
@@ -1760,11 +1752,20 @@ static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data)
 	}
 
 	if ((sb->s_flags & MS_RDONLY) && !(*flags & MS_RDONLY)) {
+		if (c->ro_media) {
+			ubifs_msg("cannot re-mount due to prior errors");
+			return -EROFS;
+		}
 		err = ubifs_remount_rw(c);
 		if (err)
 			return err;
-	} else if (!(sb->s_flags & MS_RDONLY) && (*flags & MS_RDONLY))
+	} else if (!(sb->s_flags & MS_RDONLY) && (*flags & MS_RDONLY)) {
+		if (c->ro_media) {
+			ubifs_msg("cannot re-mount due to prior errors");
+			return -EROFS;
+		}
 		ubifs_remount_ro(c);
+	}
 
 	if (c->bulk_read == 1)
 		bu_init(c);
@@ -1774,10 +1775,11 @@ static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data)
 		c->bu.buf = NULL;
 	}
 
+	ubifs_assert(c->lst.taken_empty_lebs == 1);
 	return 0;
 }
 
-struct super_operations ubifs_super_operations = {
+const struct super_operations ubifs_super_operations = {
 	.alloc_inode   = ubifs_alloc_inode,
 	.destroy_inode = ubifs_destroy_inode,
 	.put_super     = ubifs_put_super,
@@ -2044,15 +2046,6 @@ out_close:
 
 static void ubifs_kill_sb(struct super_block *sb)
 {
-	struct ubifs_info *c = sb->s_fs_info;
-
-	/*
-	 * We do 'commit_on_unmount()' here instead of 'ubifs_put_super()'
-	 * in order to be outside BKL.
-	 */
-	if (sb->s_root)
-		commit_on_unmount(c);
-	/* The un-mount routine is actually done in put_super() */
 	generic_shutdown_super(sb);
 }
 
diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c
index f7e36f54552..fa28a84c6a1 100644
--- a/fs/ubifs/tnc.c
+++ b/fs/ubifs/tnc.c
@@ -443,6 +443,11 @@ static int tnc_read_node_nm(struct ubifs_info *c, struct ubifs_zbranch *zbr,
  * This function performs that same function as ubifs_read_node except that
  * it does not require that there is actually a node present and instead
  * the return code indicates if a node was read.
+ *
+ * Note, this function does not check CRC of data nodes if @c->no_chk_data_crc
+ * is true (it is controlled by corresponding mount option). However, if
+ * @c->always_chk_crc is true, @c->no_chk_data_crc is ignored and CRC is always
+ * checked.
  */
 static int try_read_node(const struct ubifs_info *c, void *buf, int type,
 			 int len, int lnum, int offs)
@@ -470,9 +475,8 @@ static int try_read_node(const struct ubifs_info *c, void *buf, int type,
 	if (node_len != len)
 		return 0;
 
-	if (type == UBIFS_DATA_NODE && !c->always_chk_crc)
-		if (c->no_chk_data_crc)
-			return 0;
+	if (type == UBIFS_DATA_NODE && !c->always_chk_crc && c->no_chk_data_crc)
+		return 1;
 
 	crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
 	node_crc = le32_to_cpu(ch->crc);
@@ -1506,7 +1510,7 @@ out:
  *
  * Note, if the bulk-read buffer length (@bu->buf_len) is known, this function
  * makes sure bulk-read nodes fit the buffer. Otherwise, this function prepares
- * maxumum possible amount of nodes for bulk-read.
+ * maximum possible amount of nodes for bulk-read.
  */
 int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu)
 {
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index fc2a4cc66d0..039a68bee29 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -426,9 +426,9 @@ struct ubifs_unclean_leb {
  * LEB properties flags.
  *
  * LPROPS_UNCAT: not categorized
- * LPROPS_DIRTY: dirty > 0, not index
+ * LPROPS_DIRTY: dirty > free, dirty >= @c->dead_wm, not index
  * LPROPS_DIRTY_IDX: dirty + free > @c->min_idx_node_sze and index
- * LPROPS_FREE: free > 0, not empty, not index
+ * LPROPS_FREE: free > 0, dirty < @c->dead_wm, not empty, not index
  * LPROPS_HEAP_CNT: number of heaps used for storing categorized LEBs
  * LPROPS_EMPTY: LEB is empty, not taken
  * LPROPS_FREEABLE: free + dirty == leb_size, not index, not taken
@@ -961,7 +961,6 @@ struct ubifs_debug_info;
  * @cs_lock: commit state lock
  * @cmt_wq: wait queue to sleep on if the log is full and a commit is running
  *
- * @fast_unmount: do not run journal commit before un-mounting
  * @big_lpt: flag that LPT is too big to write whole during commit
  * @no_chk_data_crc: do not check CRCs when reading data nodes (except during
  *                   recovery)
@@ -1202,7 +1201,6 @@ struct ubifs_info {
 	spinlock_t cs_lock;
 	wait_queue_head_t cmt_wq;
 
-	unsigned int fast_unmount:1;
 	unsigned int big_lpt:1;
 	unsigned int no_chk_data_crc:1;
 	unsigned int bulk_read:1;
@@ -1405,13 +1403,13 @@ extern struct list_head ubifs_infos;
 extern spinlock_t ubifs_infos_lock;
 extern atomic_long_t ubifs_clean_zn_cnt;
 extern struct kmem_cache *ubifs_inode_slab;
-extern struct super_operations ubifs_super_operations;
-extern struct address_space_operations ubifs_file_address_operations;
-extern struct file_operations ubifs_file_operations;
-extern struct inode_operations ubifs_file_inode_operations;
-extern struct file_operations ubifs_dir_operations;
-extern struct inode_operations ubifs_dir_inode_operations;
-extern struct inode_operations ubifs_symlink_inode_operations;
+extern const struct super_operations ubifs_super_operations;
+extern const struct address_space_operations ubifs_file_address_operations;
+extern const struct file_operations ubifs_file_operations;
+extern const struct inode_operations ubifs_file_inode_operations;
+extern const struct file_operations ubifs_dir_operations;
+extern const struct inode_operations ubifs_dir_inode_operations;
+extern const struct inode_operations ubifs_symlink_inode_operations;
 extern struct backing_dev_info ubifs_backing_dev_info;
 extern struct ubifs_compressor *ubifs_compressors[UBIFS_COMPR_TYPES_CNT];
 
@@ -1428,7 +1426,7 @@ int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len,
 int ubifs_write_node(struct ubifs_info *c, void *node, int len, int lnum,
 		     int offs, int dtype);
 int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum,
-		     int offs, int quiet, int chk_crc);
+		     int offs, int quiet, int must_chk_crc);
 void ubifs_prepare_node(struct ubifs_info *c, void *buf, int len, int pad);
 void ubifs_prep_grp_node(struct ubifs_info *c, void *node, int len, int last);
 int ubifs_io_init(struct ubifs_info *c);
@@ -1495,6 +1493,7 @@ void ubifs_release_ino_dirty(struct ubifs_info *c, struct inode *inode,
 void ubifs_cancel_ino_op(struct ubifs_info *c, struct inode *inode,
 			 struct ubifs_budget_req *req);
 long long ubifs_get_free_space(struct ubifs_info *c);
+long long ubifs_get_free_space_nolock(struct ubifs_info *c);
 int ubifs_calc_min_idx_lebs(struct ubifs_info *c);
 void ubifs_convert_page_budget(struct ubifs_info *c);
 long long ubifs_reported_space(const struct ubifs_info *c, long long free);
@@ -1603,6 +1602,7 @@ void ubifs_delete_orphan(struct ubifs_info *c, ino_t inum);
 int ubifs_orphan_start_commit(struct ubifs_info *c);
 int ubifs_orphan_end_commit(struct ubifs_info *c);
 int ubifs_mount_orphans(struct ubifs_info *c, int unclean, int read_only);
+int ubifs_clear_orphans(struct ubifs_info *c);
 
 /* lpt.c */
 int ubifs_calc_lpt_geom(struct ubifs_info *c);
@@ -1646,7 +1646,7 @@ const struct ubifs_lprops *ubifs_change_lp(struct ubifs_info *c,
 					   const struct ubifs_lprops *lp,
 					   int free, int dirty, int flags,
 					   int idx_gc_cnt);
-void ubifs_get_lp_stats(struct ubifs_info *c, struct ubifs_lp_stats *stats);
+void ubifs_get_lp_stats(struct ubifs_info *c, struct ubifs_lp_stats *lst);
 void ubifs_add_to_cat(struct ubifs_info *c, struct ubifs_lprops *lprops,
 		      int cat);
 void ubifs_replace_cat(struct ubifs_info *c, struct ubifs_lprops *old_lprops,