Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 1995 insertions, 0 deletions

diff --git a/fs/ubifs/lpt_commit.c b/fs/ubifs/lpt_commit.c
new file mode 100644
index 000000000..f2cb21458
--- /dev/null
+++ b/fs/ubifs/lpt_commit.c
@@ -0,0 +1,1995 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Adrian Hunter
+ *          Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/*
+ * This file implements commit-related functionality of the LEB properties
+ * subsystem.
+ */
+
+#include <linux/crc16.h>
+#include <linux/slab.h>
+#include <linux/random.h>
+#include "ubifs.h"
+
+static int dbg_populate_lsave(struct ubifs_info *c);
+
+/**
+ * first_dirty_cnode - find first dirty cnode.
+ * @c: UBIFS file-system description object
+ * @nnode: nnode at which to start
+ *
+ * This function returns the first dirty cnode or %NULL if there is not one.
+ */
+static struct ubifs_cnode *first_dirty_cnode(const struct ubifs_info *c, struct ubifs_nnode *nnode)
+{
+	ubifs_assert(c, nnode);
+	while (1) {
+		int i, cont = 0;
+
+		for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+			struct ubifs_cnode *cnode;
+
+			cnode = nnode->nbranch[i].cnode;
+			if (cnode &&
+			    test_bit(DIRTY_CNODE, &cnode->flags)) {
+				if (cnode->level == 0)
+					return cnode;
+				nnode = (struct ubifs_nnode *)cnode;
+				cont = 1;
+				break;
+			}
+		}
+		if (!cont)
+			return (struct ubifs_cnode *)nnode;
+	}
+}
+
+/**
+ * next_dirty_cnode - find next dirty cnode.
+ * @c: UBIFS file-system description object
+ * @cnode: cnode from which to begin searching
+ *
+ * This function returns the next dirty cnode or %NULL if there is not one.
+ */
+static struct ubifs_cnode *next_dirty_cnode(const struct ubifs_info *c, struct ubifs_cnode *cnode)
+{
+	struct ubifs_nnode *nnode;
+	int i;
+
+	ubifs_assert(c, cnode);
+	nnode = cnode->parent;
+	if (!nnode)
+		return NULL;
+	for (i = cnode->iip + 1; i < UBIFS_LPT_FANOUT; i++) {
+		cnode = nnode->nbranch[i].cnode;
+		if (cnode && test_bit(DIRTY_CNODE, &cnode->flags)) {
+			if (cnode->level == 0)
+				return cnode; /* cnode is a pnode */
+			/* cnode is a nnode */
+			return first_dirty_cnode(c, (struct ubifs_nnode *)cnode);
+		}
+	}
+	return (struct ubifs_cnode *)nnode;
+}
+
+/**
+ * get_cnodes_to_commit - create list of dirty cnodes to commit.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns the number of cnodes to commit.
+ */
+static int get_cnodes_to_commit(struct ubifs_info *c)
+{
+	struct ubifs_cnode *cnode, *cnext;
+	int cnt = 0;
+
+	if (!c->nroot)
+		return 0;
+
+	if (!test_bit(DIRTY_CNODE, &c->nroot->flags))
+		return 0;
+
+	c->lpt_cnext = first_dirty_cnode(c, c->nroot);
+	cnode = c->lpt_cnext;
+	if (!cnode)
+		return 0;
+	cnt += 1;
+	while (1) {
+		ubifs_assert(c, !test_bit(COW_CNODE, &cnode->flags));
+		__set_bit(COW_CNODE, &cnode->flags);
+		cnext = next_dirty_cnode(c, cnode);
+		if (!cnext) {
+			cnode->cnext = c->lpt_cnext;
+			break;
+		}
+		cnode->cnext = cnext;
+		cnode = cnext;
+		cnt += 1;
+	}
+	dbg_cmt("committing %d cnodes", cnt);
+	dbg_lp("committing %d cnodes", cnt);
+	ubifs_assert(c, cnt == c->dirty_nn_cnt + c->dirty_pn_cnt);
+	return cnt;
+}
+
+/**
+ * upd_ltab - update LPT LEB properties.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number
+ * @free: amount of free space
+ * @dirty: amount of dirty space to add
+ */
+static void upd_ltab(struct ubifs_info *c, int lnum, int free, int dirty)
+{
+	dbg_lp("LEB %d free %d dirty %d to %d +%d",
+	       lnum, c->ltab[lnum - c->lpt_first].free,
+	       c->ltab[lnum - c->lpt_first].dirty, free, dirty);
+	ubifs_assert(c, lnum >= c->lpt_first && lnum <= c->lpt_last);
+	c->ltab[lnum - c->lpt_first].free = free;
+	c->ltab[lnum - c->lpt_first].dirty += dirty;
+}
+
+/**
+ * alloc_lpt_leb - allocate an LPT LEB that is empty.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number is passed and returned here
+ *
+ * This function finds the next empty LEB in the ltab starting from @lnum. If a
+ * an empty LEB is found it is returned in @lnum and the function returns %0.
+ * Otherwise the function returns -ENOSPC.  Note however, that LPT is designed
+ * never to run out of space.
+ */
+static int alloc_lpt_leb(struct ubifs_info *c, int *lnum)
+{
+	int i, n;
+
+	n = *lnum - c->lpt_first + 1;
+	for (i = n; i < c->lpt_lebs; i++) {
+		if (c->ltab[i].tgc || c->ltab[i].cmt)
+			continue;
+		if (c->ltab[i].free == c->leb_size) {
+			c->ltab[i].cmt = 1;
+			*lnum = i + c->lpt_first;
+			return 0;
+		}
+	}
+
+	for (i = 0; i < n; i++) {
+		if (c->ltab[i].tgc || c->ltab[i].cmt)
+			continue;
+		if (c->ltab[i].free == c->leb_size) {
+			c->ltab[i].cmt = 1;
+			*lnum = i + c->lpt_first;
+			return 0;
+		}
+	}
+	return -ENOSPC;
+}
+
+/**
+ * layout_cnodes - layout cnodes for commit.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int layout_cnodes(struct ubifs_info *c)
+{
+	int lnum, offs, len, alen, done_lsave, done_ltab, err;
+	struct ubifs_cnode *cnode;
+
+	err = dbg_chk_lpt_sz(c, 0, 0);
+	if (err)
+		return err;
+	cnode = c->lpt_cnext;
+	if (!cnode)
+		return 0;
+	lnum = c->nhead_lnum;
+	offs = c->nhead_offs;
+	/* Try to place lsave and ltab nicely */
+	done_lsave = !c->big_lpt;
+	done_ltab = 0;
+	if (!done_lsave && offs + c->lsave_sz <= c->leb_size) {
+		done_lsave = 1;
+		c->lsave_lnum = lnum;
+		c->lsave_offs = offs;
+		offs += c->lsave_sz;
+		dbg_chk_lpt_sz(c, 1, c->lsave_sz);
+	}
+
+	if (offs + c->ltab_sz <= c->leb_size) {
+		done_ltab = 1;
+		c->ltab_lnum = lnum;
+		c->ltab_offs = offs;
+		offs += c->ltab_sz;
+		dbg_chk_lpt_sz(c, 1, c->ltab_sz);
+	}
+
+	do {
+		if (cnode->level) {
+			len = c->nnode_sz;
+			c->dirty_nn_cnt -= 1;
+		} else {
+			len = c->pnode_sz;
+			c->dirty_pn_cnt -= 1;
+		}
+		while (offs + len > c->leb_size) {
+			alen = ALIGN(offs, c->min_io_size);
+			upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
+			dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
+			err = alloc_lpt_leb(c, &lnum);
+			if (err)
+				goto no_space;
+			offs = 0;
+			ubifs_assert(c, lnum >= c->lpt_first &&
+				     lnum <= c->lpt_last);
+			/* Try to place lsave and ltab nicely */
+			if (!done_lsave) {
+				done_lsave = 1;
+				c->lsave_lnum = lnum;
+				c->lsave_offs = offs;
+				offs += c->lsave_sz;
+				dbg_chk_lpt_sz(c, 1, c->lsave_sz);
+				continue;
+			}
+			if (!done_ltab) {
+				done_ltab = 1;
+				c->ltab_lnum = lnum;
+				c->ltab_offs = offs;
+				offs += c->ltab_sz;
+				dbg_chk_lpt_sz(c, 1, c->ltab_sz);
+				continue;
+			}
+			break;
+		}
+		if (cnode->parent) {
+			cnode->parent->nbranch[cnode->iip].lnum = lnum;
+			cnode->parent->nbranch[cnode->iip].offs = offs;
+		} else {
+			c->lpt_lnum = lnum;
+			c->lpt_offs = offs;
+		}
+		offs += len;
+		dbg_chk_lpt_sz(c, 1, len);
+		cnode = cnode->cnext;
+	} while (cnode && cnode != c->lpt_cnext);
+
+	/* Make sure to place LPT's save table */
+	if (!done_lsave) {
+		if (offs + c->lsave_sz > c->leb_size) {
+			alen = ALIGN(offs, c->min_io_size);
+			upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
+			dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
+			err = alloc_lpt_leb(c, &lnum);
+			if (err)
+				goto no_space;
+			offs = 0;
+			ubifs_assert(c, lnum >= c->lpt_first &&
+				     lnum <= c->lpt_last);
+		}
+		done_lsave = 1;
+		c->lsave_lnum = lnum;
+		c->lsave_offs = offs;
+		offs += c->lsave_sz;
+		dbg_chk_lpt_sz(c, 1, c->lsave_sz);
+	}
+
+	/* Make sure to place LPT's own lprops table */
+	if (!done_ltab) {
+		if (offs + c->ltab_sz > c->leb_size) {
+			alen = ALIGN(offs, c->min_io_size);
+			upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
+			dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
+			err = alloc_lpt_leb(c, &lnum);
+			if (err)
+				goto no_space;
+			offs = 0;
+			ubifs_assert(c, lnum >= c->lpt_first &&
+				     lnum <= c->lpt_last);
+		}
+		c->ltab_lnum = lnum;
+		c->ltab_offs = offs;
+		offs += c->ltab_sz;
+		dbg_chk_lpt_sz(c, 1, c->ltab_sz);
+	}
+
+	alen = ALIGN(offs, c->min_io_size);
+	upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
+	dbg_chk_lpt_sz(c, 4, alen - offs);
+	err = dbg_chk_lpt_sz(c, 3, alen);
+	if (err)
+		return err;
+	return 0;
+
+no_space:
+	ubifs_err(c, "LPT out of space at LEB %d:%d needing %d, done_ltab %d, done_lsave %d",
+		  lnum, offs, len, done_ltab, done_lsave);
+	ubifs_dump_lpt_info(c);
+	ubifs_dump_lpt_lebs(c);
+	dump_stack();
+	return err;
+}
+
+/**
+ * realloc_lpt_leb - allocate an LPT LEB that is empty.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number is passed and returned here
+ *
+ * This function duplicates exactly the results of the function alloc_lpt_leb.
+ * It is used during end commit to reallocate the same LEB numbers that were
+ * allocated by alloc_lpt_leb during start commit.
+ *
+ * This function finds the next LEB that was allocated by the alloc_lpt_leb
+ * function starting from @lnum. If a LEB is found it is returned in @lnum and
+ * the function returns %0. Otherwise the function returns -ENOSPC.
+ * Note however, that LPT is designed never to run out of space.
+ */
+static int realloc_lpt_leb(struct ubifs_info *c, int *lnum)
+{
+	int i, n;
+
+	n = *lnum - c->lpt_first + 1;
+	for (i = n; i < c->lpt_lebs; i++)
+		if (c->ltab[i].cmt) {
+			c->ltab[i].cmt = 0;
+			*lnum = i + c->lpt_first;
+			return 0;
+		}
+
+	for (i = 0; i < n; i++)
+		if (c->ltab[i].cmt) {
+			c->ltab[i].cmt = 0;
+			*lnum = i + c->lpt_first;
+			return 0;
+		}
+	return -ENOSPC;
+}
+
+/**
+ * write_cnodes - write cnodes for commit.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int write_cnodes(struct ubifs_info *c)
+{
+	int lnum, offs, len, from, err, wlen, alen, done_ltab, done_lsave;
+	struct ubifs_cnode *cnode;
+	void *buf = c->lpt_buf;
+
+	cnode = c->lpt_cnext;
+	if (!cnode)
+		return 0;
+	lnum = c->nhead_lnum;
+	offs = c->nhead_offs;
+	from = offs;
+	/* Ensure empty LEB is unmapped */
+	if (offs == 0) {
+		err = ubifs_leb_unmap(c, lnum);
+		if (err)
+			return err;
+	}
+	/* Try to place lsave and ltab nicely */
+	done_lsave = !c->big_lpt;
+	done_ltab = 0;
+	if (!done_lsave && offs + c->lsave_sz <= c->leb_size) {
+		done_lsave = 1;
+		ubifs_pack_lsave(c, buf + offs, c->lsave);
+		offs += c->lsave_sz;
+		dbg_chk_lpt_sz(c, 1, c->lsave_sz);
+	}
+
+	if (offs + c->ltab_sz <= c->leb_size) {
+		done_ltab = 1;
+		ubifs_pack_ltab(c, buf + offs, c->ltab_cmt);
+		offs += c->ltab_sz;
+		dbg_chk_lpt_sz(c, 1, c->ltab_sz);
+	}
+
+	/* Loop for each cnode */
+	do {
+		if (cnode->level)
+			len = c->nnode_sz;
+		else
+			len = c->pnode_sz;
+		while (offs + len > c->leb_size) {
+			wlen = offs - from;
+			if (wlen) {
+				alen = ALIGN(wlen, c->min_io_size);
+				memset(buf + offs, 0xff, alen - wlen);
+				err = ubifs_leb_write(c, lnum, buf + from, from,
+						       alen);
+				if (err)
+					return err;
+			}
+			dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
+			err = realloc_lpt_leb(c, &lnum);
+			if (err)
+				goto no_space;
+			offs = from = 0;
+			ubifs_assert(c, lnum >= c->lpt_first &&
+				     lnum <= c->lpt_last);
+			err = ubifs_leb_unmap(c, lnum);
+			if (err)
+				return err;
+			/* Try to place lsave and ltab nicely */
+			if (!done_lsave) {
+				done_lsave = 1;
+				ubifs_pack_lsave(c, buf + offs, c->lsave);
+				offs += c->lsave_sz;
+				dbg_chk_lpt_sz(c, 1, c->lsave_sz);
+				continue;
+			}
+			if (!done_ltab) {
+				done_ltab = 1;
+				ubifs_pack_ltab(c, buf + offs, c->ltab_cmt);
+				offs += c->ltab_sz;
+				dbg_chk_lpt_sz(c, 1, c->ltab_sz);
+				continue;
+			}
+			break;
+		}
+		if (cnode->level)
+			ubifs_pack_nnode(c, buf + offs,
+					 (struct ubifs_nnode *)cnode);
+		else
+			ubifs_pack_pnode(c, buf + offs,
+					 (struct ubifs_pnode *)cnode);
+		/*
+		 * The reason for the barriers is the same as in case of TNC.
+		 * See comment in 'write_index()'. 'dirty_cow_nnode()' and
+		 * 'dirty_cow_pnode()' are the functions for which this is
+		 * important.
+		 */
+		clear_bit(DIRTY_CNODE, &cnode->flags);
+		smp_mb__before_atomic();
+		clear_bit(COW_CNODE, &cnode->flags);
+		smp_mb__after_atomic();
+		offs += len;
+		dbg_chk_lpt_sz(c, 1, len);
+		cnode = cnode->cnext;
+	} while (cnode && cnode != c->lpt_cnext);
+
+	/* Make sure to place LPT's save table */
+	if (!done_lsave) {
+		if (offs + c->lsave_sz > c->leb_size) {
+			wlen = offs - from;
+			alen = ALIGN(wlen, c->min_io_size);
+			memset(buf + offs, 0xff, alen - wlen);
+			err = ubifs_leb_write(c, lnum, buf + from, from, alen);
+			if (err)
+				return err;
+			dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
+			err = realloc_lpt_leb(c, &lnum);
+			if (err)
+				goto no_space;
+			offs = from = 0;
+			ubifs_assert(c, lnum >= c->lpt_first &&
+				     lnum <= c->lpt_last);
+			err = ubifs_leb_unmap(c, lnum);
+			if (err)
+				return err;
+		}
+		done_lsave = 1;
+		ubifs_pack_lsave(c, buf + offs, c->lsave);
+		offs += c->lsave_sz;
+		dbg_chk_lpt_sz(c, 1, c->lsave_sz);
+	}
+
+	/* Make sure to place LPT's own lprops table */
+	if (!done_ltab) {
+		if (offs + c->ltab_sz > c->leb_size) {
+			wlen = offs - from;
+			alen = ALIGN(wlen, c->min_io_size);
+			memset(buf + offs, 0xff, alen - wlen);
+			err = ubifs_leb_write(c, lnum, buf + from, from, alen);
+			if (err)
+				return err;
+			dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
+			err = realloc_lpt_leb(c, &lnum);
+			if (err)
+				goto no_space;
+			offs = from = 0;
+			ubifs_assert(c, lnum >= c->lpt_first &&
+				     lnum <= c->lpt_last);
+			err = ubifs_leb_unmap(c, lnum);
+			if (err)
+				return err;
+		}
+		ubifs_pack_ltab(c, buf + offs, c->ltab_cmt);
+		offs += c->ltab_sz;
+		dbg_chk_lpt_sz(c, 1, c->ltab_sz);
+	}
+
+	/* Write remaining data in buffer */
+	wlen = offs - from;
+	alen = ALIGN(wlen, c->min_io_size);
+	memset(buf + offs, 0xff, alen - wlen);
+	err = ubifs_leb_write(c, lnum, buf + from, from, alen);
+	if (err)
+		return err;
+
+	dbg_chk_lpt_sz(c, 4, alen - wlen);
+	err = dbg_chk_lpt_sz(c, 3, ALIGN(offs, c->min_io_size));
+	if (err)
+		return err;
+
+	c->nhead_lnum = lnum;
+	c->nhead_offs = ALIGN(offs, c->min_io_size);
+
+	dbg_lp("LPT root is at %d:%d", c->lpt_lnum, c->lpt_offs);
+	dbg_lp("LPT head is at %d:%d", c->nhead_lnum, c->nhead_offs);
+	dbg_lp("LPT ltab is at %d:%d", c->ltab_lnum, c->ltab_offs);
+	if (c->big_lpt)
+		dbg_lp("LPT lsave is at %d:%d", c->lsave_lnum, c->lsave_offs);
+
+	return 0;
+
+no_space:
+	ubifs_err(c, "LPT out of space mismatch at LEB %d:%d needing %d, done_ltab %d, done_lsave %d",
+		  lnum, offs, len, done_ltab, done_lsave);
+	ubifs_dump_lpt_info(c);
+	ubifs_dump_lpt_lebs(c);
+	dump_stack();
+	return err;
+}
+
+/**
+ * next_pnode_to_dirty - find next pnode to dirty.
+ * @c: UBIFS file-system description object
+ * @pnode: pnode
+ *
+ * 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_to_dirty(struct ubifs_info *c,
+					       struct ubifs_pnode *pnode)
+{
+	struct ubifs_nnode *nnode;
+	int iip;
+
+	/* Try to go right */
+	nnode = pnode->parent;
+	for (iip = pnode->iip + 1; iip < UBIFS_LPT_FANOUT; iip++) {
+		if (nnode->nbranch[iip].lnum)
+			return ubifs_get_pnode(c, nnode, iip);
+	}
+
+	/* Go up while can't go right */
+	do {
+		iip = nnode->iip + 1;
+		nnode = nnode->parent;
+		if (!nnode)
+			return NULL;
+		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);
+	if (IS_ERR(nnode))
+		return ERR_CAST(nnode);
+
+	/* Go down to level 1 */
+	while (nnode->level > 1) {
+		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 ERR_CAST(nnode);
+	}
+
+	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);
+}
+
+/**
+ * add_pnode_dirt - add dirty space to LPT LEB properties.
+ * @c: UBIFS file-system description object
+ * @pnode: pnode for which to add dirt
+ */
+static void add_pnode_dirt(struct ubifs_info *c, struct ubifs_pnode *pnode)
+{
+	ubifs_add_lpt_dirt(c, pnode->parent->nbranch[pnode->iip].lnum,
+			   c->pnode_sz);
+}
+
+/**
+ * do_make_pnode_dirty - mark a pnode dirty.
+ * @c: UBIFS file-system description object
+ * @pnode: pnode to mark dirty
+ */
+static void do_make_pnode_dirty(struct ubifs_info *c, struct ubifs_pnode *pnode)
+{
+	/* Assumes cnext list is empty i.e. not called during commit */
+	if (!test_and_set_bit(DIRTY_CNODE, &pnode->flags)) {
+		struct ubifs_nnode *nnode;
+
+		c->dirty_pn_cnt += 1;
+		add_pnode_dirt(c, pnode);
+		/* Mark parent and ancestors dirty too */
+		nnode = pnode->parent;
+		while (nnode) {
+			if (!test_and_set_bit(DIRTY_CNODE, &nnode->flags)) {
+				c->dirty_nn_cnt += 1;
+				ubifs_add_nnode_dirt(c, nnode);
+				nnode = nnode->parent;
+			} else
+				break;
+		}
+	}
+}
+
+/**
+ * make_tree_dirty - mark the entire LEB properties tree dirty.
+ * @c: UBIFS file-system description object
+ *
+ * This function is used by the "small" LPT model to cause the entire LEB
+ * properties tree to be written.  The "small" LPT model does not use LPT
+ * garbage collection because it is more efficient to write the entire tree
+ * (because it is small).
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int make_tree_dirty(struct ubifs_info *c)
+{
+	struct ubifs_pnode *pnode;
+
+	pnode = ubifs_pnode_lookup(c, 0);
+	if (IS_ERR(pnode))
+		return PTR_ERR(pnode);
+
+	while (pnode) {
+		do_make_pnode_dirty(c, pnode);
+		pnode = next_pnode_to_dirty(c, pnode);
+		if (IS_ERR(pnode))
+			return PTR_ERR(pnode);
+	}
+	return 0;
+}
+
+/**
+ * need_write_all - determine if the LPT area is running out of free space.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns %1 if the LPT area is running out of free space and %0
+ * if it is not.
+ */
+static int need_write_all(struct ubifs_info *c)
+{
+	long long free = 0;
+	int i;
+
+	for (i = 0; i < c->lpt_lebs; i++) {
+		if (i + c->lpt_first == c->nhead_lnum)
+			free += c->leb_size - c->nhead_offs;
+		else if (c->ltab[i].free == c->leb_size)
+			free += c->leb_size;
+		else if (c->ltab[i].free + c->ltab[i].dirty == c->leb_size)
+			free += c->leb_size;
+	}
+	/* Less than twice the size left */
+	if (free <= c->lpt_sz * 2)
+		return 1;
+	return 0;
+}
+
+/**
+ * lpt_tgc_start - start trivial garbage collection of LPT LEBs.
+ * @c: UBIFS file-system description object
+ *
+ * LPT trivial garbage collection is where a LPT LEB contains only dirty and
+ * free space and so may be reused as soon as the next commit is completed.
+ * This function is called during start commit to mark LPT LEBs for trivial GC.
+ */
+static void lpt_tgc_start(struct ubifs_info *c)
+{
+	int i;
+
+	for (i = 0; i < c->lpt_lebs; i++) {
+		if (i + c->lpt_first == c->nhead_lnum)
+			continue;
+		if (c->ltab[i].dirty > 0 &&
+		    c->ltab[i].free + c->ltab[i].dirty == c->leb_size) {
+			c->ltab[i].tgc = 1;
+			c->ltab[i].free = c->leb_size;
+			c->ltab[i].dirty = 0;
+			dbg_lp("LEB %d", i + c->lpt_first);
+		}
+	}
+}
+
+/**
+ * lpt_tgc_end - end trivial garbage collection of LPT LEBs.
+ * @c: UBIFS file-system description object
+ *
+ * LPT trivial garbage collection is where a LPT LEB contains only dirty and
+ * free space and so may be reused as soon as the next commit is completed.
+ * This function is called after the commit is completed (master node has been
+ * written) and un-maps LPT LEBs that were marked for trivial GC.
+ */
+static int lpt_tgc_end(struct ubifs_info *c)
+{
+	int i, err;
+
+	for (i = 0; i < c->lpt_lebs; i++)
+		if (c->ltab[i].tgc) {
+			err = ubifs_leb_unmap(c, i + c->lpt_first);
+			if (err)
+				return err;
+			c->ltab[i].tgc = 0;
+			dbg_lp("LEB %d", i + c->lpt_first);
+		}
+	return 0;
+}
+
+/**
+ * populate_lsave - fill the lsave array with important LEB numbers.
+ * @c: the UBIFS file-system description object
+ *
+ * This function is only called for the "big" model. It records a small number
+ * of LEB numbers of important LEBs.  Important LEBs are ones that are (from
+ * most important to least important): empty, freeable, freeable index, dirty
+ * index, dirty or free. Upon mount, we read this list of LEB numbers and bring
+ * their pnodes into memory.  That will stop us from having to scan the LPT
+ * straight away. For the "small" model we assume that scanning the LPT is no
+ * big deal.
+ */
+static void populate_lsave(struct ubifs_info *c)
+{
+	struct ubifs_lprops *lprops;
+	struct ubifs_lpt_heap *heap;
+	int i, cnt = 0;
+
+	ubifs_assert(c, c->big_lpt);
+	if (!(c->lpt_drty_flgs & LSAVE_DIRTY)) {
+		c->lpt_drty_flgs |= LSAVE_DIRTY;
+		ubifs_add_lpt_dirt(c, c->lsave_lnum, c->lsave_sz);
+	}
+
+	if (dbg_populate_lsave(c))
+		return;
+
+	list_for_each_entry(lprops, &c->empty_list, list) {
+		c->lsave[cnt++] = lprops->lnum;
+		if (cnt >= c->lsave_cnt)
+			return;
+	}
+	list_for_each_entry(lprops, &c->freeable_list, list) {
+		c->lsave[cnt++] = lprops->lnum;
+		if (cnt >= c->lsave_cnt)
+			return;
+	}
+	list_for_each_entry(lprops, &c->frdi_idx_list, list) {
+		c->lsave[cnt++] = lprops->lnum;
+		if (cnt >= c->lsave_cnt)
+			return;
+	}
+	heap = &c->lpt_heap[LPROPS_DIRTY_IDX - 1];
+	for (i = 0; i < heap->cnt; i++) {
+		c->lsave[cnt++] = heap->arr[i]->lnum;
+		if (cnt >= c->lsave_cnt)
+			return;
+	}
+	heap = &c->lpt_heap[LPROPS_DIRTY - 1];
+	for (i = 0; i < heap->cnt; i++) {
+		c->lsave[cnt++] = heap->arr[i]->lnum;
+		if (cnt >= c->lsave_cnt)
+			return;
+	}
+	heap = &c->lpt_heap[LPROPS_FREE - 1];
+	for (i = 0; i < heap->cnt; i++) {
+		c->lsave[cnt++] = heap->arr[i]->lnum;
+		if (cnt >= c->lsave_cnt)
+			return;
+	}
+	/* Fill it up completely */
+	while (cnt < c->lsave_cnt)
+		c->lsave[cnt++] = c->main_first;
+}
+
+/**
+ * nnode_lookup - lookup a nnode in the LPT.
+ * @c: UBIFS file-system description object
+ * @i: nnode number
+ *
+ * This function returns a pointer to the nnode on success or a negative
+ * error code on failure.
+ */
+static struct ubifs_nnode *nnode_lookup(struct ubifs_info *c, int i)
+{
+	int err, iip;
+	struct ubifs_nnode *nnode;
+
+	if (!c->nroot) {
+		err = ubifs_read_nnode(c, NULL, 0);
+		if (err)
+			return ERR_PTR(err);
+	}
+	nnode = c->nroot;
+	while (1) {
+		iip = i & (UBIFS_LPT_FANOUT - 1);
+		i >>= UBIFS_LPT_FANOUT_SHIFT;
+		if (!i)
+			break;
+		nnode = ubifs_get_nnode(c, nnode, iip);
+		if (IS_ERR(nnode))
+			return nnode;
+	}
+	return nnode;
+}
+
+/**
+ * make_nnode_dirty - find a nnode and, if found, make it dirty.
+ * @c: UBIFS file-system description object
+ * @node_num: nnode number of nnode to make dirty
+ * @lnum: LEB number where nnode was written
+ * @offs: offset where nnode was written
+ *
+ * This function is used by LPT garbage collection.  LPT garbage collection is
+ * used only for the "big" LPT model (c->big_lpt == 1).  Garbage collection
+ * simply involves marking all the nodes in the LEB being garbage-collected as
+ * dirty.  The dirty nodes are written next commit, after which the LEB is free
+ * to be reused.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int make_nnode_dirty(struct ubifs_info *c, int node_num, int lnum,
+			    int offs)
+{
+	struct ubifs_nnode *nnode;
+
+	nnode = nnode_lookup(c, node_num);
+	if (IS_ERR(nnode))
+		return PTR_ERR(nnode);
+	if (nnode->parent) {
+		struct ubifs_nbranch *branch;
+
+		branch = &nnode->parent->nbranch[nnode->iip];
+		if (branch->lnum != lnum || branch->offs != offs)
+			return 0; /* nnode is obsolete */
+	} else if (c->lpt_lnum != lnum || c->lpt_offs != offs)
+			return 0; /* nnode is obsolete */
+	/* Assumes cnext list is empty i.e. not called during commit */
+	if (!test_and_set_bit(DIRTY_CNODE, &nnode->flags)) {
+		c->dirty_nn_cnt += 1;
+		ubifs_add_nnode_dirt(c, nnode);
+		/* Mark parent and ancestors dirty too */
+		nnode = nnode->parent;
+		while (nnode) {
+			if (!test_and_set_bit(DIRTY_CNODE, &nnode->flags)) {
+				c->dirty_nn_cnt += 1;
+				ubifs_add_nnode_dirt(c, nnode);
+				nnode = nnode->parent;
+			} else
+				break;
+		}
+	}
+	return 0;
+}
+
+/**
+ * make_pnode_dirty - find a pnode and, if found, make it dirty.
+ * @c: UBIFS file-system description object
+ * @node_num: pnode number of pnode to make dirty
+ * @lnum: LEB number where pnode was written
+ * @offs: offset where pnode was written
+ *
+ * This function is used by LPT garbage collection.  LPT garbage collection is
+ * used only for the "big" LPT model (c->big_lpt == 1).  Garbage collection
+ * simply involves marking all the nodes in the LEB being garbage-collected as
+ * dirty.  The dirty nodes are written next commit, after which the LEB is free
+ * to be reused.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int make_pnode_dirty(struct ubifs_info *c, int node_num, int lnum,
+			    int offs)
+{
+	struct ubifs_pnode *pnode;
+	struct ubifs_nbranch *branch;
+
+	pnode = ubifs_pnode_lookup(c, node_num);
+	if (IS_ERR(pnode))
+		return PTR_ERR(pnode);
+	branch = &pnode->parent->nbranch[pnode->iip];
+	if (branch->lnum != lnum || branch->offs != offs)
+		return 0;
+	do_make_pnode_dirty(c, pnode);
+	return 0;
+}
+
+/**
+ * make_ltab_dirty - make ltab node dirty.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number where ltab was written
+ * @offs: offset where ltab was written
+ *
+ * This function is used by LPT garbage collection.  LPT garbage collection is
+ * used only for the "big" LPT model (c->big_lpt == 1).  Garbage collection
+ * simply involves marking all the nodes in the LEB being garbage-collected as
+ * dirty.  The dirty nodes are written next commit, after which the LEB is free
+ * to be reused.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int make_ltab_dirty(struct ubifs_info *c, int lnum, int offs)
+{
+	if (lnum != c->ltab_lnum || offs != c->ltab_offs)
+		return 0; /* This ltab node is obsolete */
+	if (!(c->lpt_drty_flgs & LTAB_DIRTY)) {
+		c->lpt_drty_flgs |= LTAB_DIRTY;
+		ubifs_add_lpt_dirt(c, c->ltab_lnum, c->ltab_sz);
+	}
+	return 0;
+}
+
+/**
+ * make_lsave_dirty - make lsave node dirty.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number where lsave was written
+ * @offs: offset where lsave was written
+ *
+ * This function is used by LPT garbage collection.  LPT garbage collection is
+ * used only for the "big" LPT model (c->big_lpt == 1).  Garbage collection
+ * simply involves marking all the nodes in the LEB being garbage-collected as
+ * dirty.  The dirty nodes are written next commit, after which the LEB is free
+ * to be reused.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int make_lsave_dirty(struct ubifs_info *c, int lnum, int offs)
+{
+	if (lnum != c->lsave_lnum || offs != c->lsave_offs)
+		return 0; /* This lsave node is obsolete */
+	if (!(c->lpt_drty_flgs & LSAVE_DIRTY)) {
+		c->lpt_drty_flgs |= LSAVE_DIRTY;
+		ubifs_add_lpt_dirt(c, c->lsave_lnum, c->lsave_sz);
+	}
+	return 0;
+}
+
+/**
+ * make_node_dirty - make node dirty.
+ * @c: UBIFS file-system description object
+ * @node_type: LPT node type
+ * @node_num: node number
+ * @lnum: LEB number where node was written
+ * @offs: offset where node was written
+ *
+ * This function is used by LPT garbage collection.  LPT garbage collection is
+ * used only for the "big" LPT model (c->big_lpt == 1).  Garbage collection
+ * simply involves marking all the nodes in the LEB being garbage-collected as
+ * dirty.  The dirty nodes are written next commit, after which the LEB is free
+ * to be reused.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int make_node_dirty(struct ubifs_info *c, int node_type, int node_num,
+			   int lnum, int offs)
+{
+	switch (node_type) {
+	case UBIFS_LPT_NNODE:
+		return make_nnode_dirty(c, node_num, lnum, offs);
+	case UBIFS_LPT_PNODE:
+		return make_pnode_dirty(c, node_num, lnum, offs);
+	case UBIFS_LPT_LTAB:
+		return make_ltab_dirty(c, lnum, offs);
+	case UBIFS_LPT_LSAVE:
+		return make_lsave_dirty(c, lnum, offs);
+	}
+	return -EINVAL;
+}
+
+/**
+ * get_lpt_node_len - return the length of a node based on its type.
+ * @c: UBIFS file-system description object
+ * @node_type: LPT node type
+ */
+static int get_lpt_node_len(const struct ubifs_info *c, int node_type)
+{
+	switch (node_type) {
+	case UBIFS_LPT_NNODE:
+		return c->nnode_sz;
+	case UBIFS_LPT_PNODE:
+		return c->pnode_sz;
+	case UBIFS_LPT_LTAB:
+		return c->ltab_sz;
+	case UBIFS_LPT_LSAVE:
+		return c->lsave_sz;
+	}
+	return 0;
+}
+
+/**
+ * get_pad_len - return the length of padding in a buffer.
+ * @c: UBIFS file-system description object
+ * @buf: buffer
+ * @len: length of buffer
+ */
+static int get_pad_len(const struct ubifs_info *c, uint8_t *buf, int len)
+{
+	int offs, pad_len;
+
+	if (c->min_io_size == 1)
+		return 0;
+	offs = c->leb_size - len;
+	pad_len = ALIGN(offs, c->min_io_size) - offs;
+	return pad_len;
+}
+
+/**
+ * get_lpt_node_type - return type (and node number) of a node in a buffer.
+ * @c: UBIFS file-system description object
+ * @buf: buffer
+ * @node_num: node number is returned here
+ */
+static int get_lpt_node_type(const struct ubifs_info *c, uint8_t *buf,
+			     int *node_num)
+{
+	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
+	int pos = 0, node_type;
+
+	node_type = ubifs_unpack_bits(c, &addr, &pos, UBIFS_LPT_TYPE_BITS);
+	*node_num = ubifs_unpack_bits(c, &addr, &pos, c->pcnt_bits);
+	return node_type;
+}
+
+/**
+ * is_a_node - determine if a buffer contains a node.
+ * @c: UBIFS file-system description object
+ * @buf: buffer
+ * @len: length of buffer
+ *
+ * This function returns %1 if the buffer contains a node or %0 if it does not.
+ */
+static int is_a_node(const struct ubifs_info *c, uint8_t *buf, int len)
+{
+	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
+	int pos = 0, node_type, node_len;
+	uint16_t crc, calc_crc;
+
+	if (len < UBIFS_LPT_CRC_BYTES + (UBIFS_LPT_TYPE_BITS + 7) / 8)
+		return 0;
+	node_type = ubifs_unpack_bits(c, &addr, &pos, UBIFS_LPT_TYPE_BITS);
+	if (node_type == UBIFS_LPT_NOT_A_NODE)
+		return 0;
+	node_len = get_lpt_node_len(c, node_type);
+	if (!node_len || node_len > len)
+		return 0;
+	pos = 0;
+	addr = buf;
+	crc = ubifs_unpack_bits(c, &addr, &pos, UBIFS_LPT_CRC_BITS);
+	calc_crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
+			 node_len - UBIFS_LPT_CRC_BYTES);
+	if (crc != calc_crc)
+		return 0;
+	return 1;
+}
+
+/**
+ * lpt_gc_lnum - garbage collect a LPT LEB.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number to garbage collect
+ *
+ * LPT garbage collection is used only for the "big" LPT model
+ * (c->big_lpt == 1).  Garbage collection simply involves marking all the nodes
+ * in the LEB being garbage-collected as dirty.  The dirty nodes are written
+ * next commit, after which the LEB is free to be reused.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int lpt_gc_lnum(struct ubifs_info *c, int lnum)
+{
+	int err, len = c->leb_size, node_type, node_num, node_len, offs;
+	void *buf = c->lpt_buf;
+
+	dbg_lp("LEB %d", lnum);
+
+	err = ubifs_leb_read(c, lnum, buf, 0, c->leb_size, 1);
+	if (err)
+		return err;
+
+	while (1) {
+		if (!is_a_node(c, buf, len)) {
+			int pad_len;
+
+			pad_len = get_pad_len(c, buf, len);
+			if (pad_len) {
+				buf += pad_len;
+				len -= pad_len;
+				continue;
+			}
+			return 0;
+		}
+		node_type = get_lpt_node_type(c, buf, &node_num);
+		node_len = get_lpt_node_len(c, node_type);
+		offs = c->leb_size - len;
+		ubifs_assert(c, node_len != 0);
+		mutex_lock(&c->lp_mutex);
+		err = make_node_dirty(c, node_type, node_num, lnum, offs);
+		mutex_unlock(&c->lp_mutex);
+		if (err)
+			return err;
+		buf += node_len;
+		len -= node_len;
+	}
+	return 0;
+}
+
+/**
+ * lpt_gc - LPT garbage collection.
+ * @c: UBIFS file-system description object
+ *
+ * Select a LPT LEB for LPT garbage collection and call 'lpt_gc_lnum()'.
+ * Returns %0 on success and a negative error code on failure.
+ */
+static int lpt_gc(struct ubifs_info *c)
+{
+	int i, lnum = -1, dirty = 0;
+
+	mutex_lock(&c->lp_mutex);
+	for (i = 0; i < c->lpt_lebs; i++) {
+		ubifs_assert(c, !c->ltab[i].tgc);
+		if (i + c->lpt_first == c->nhead_lnum ||
+		    c->ltab[i].free + c->ltab[i].dirty == c->leb_size)
+			continue;
+		if (c->ltab[i].dirty > dirty) {
+			dirty = c->ltab[i].dirty;
+			lnum = i + c->lpt_first;
+		}
+	}
+	mutex_unlock(&c->lp_mutex);
+	if (lnum == -1)
+		return -ENOSPC;
+	return lpt_gc_lnum(c, lnum);
+}
+
+/**
+ * ubifs_lpt_start_commit - UBIFS commit starts.
+ * @c: the UBIFS file-system description object
+ *
+ * This function has to be called when UBIFS starts the commit operation.
+ * This function "freezes" all currently dirty LEB properties and does not
+ * change them anymore. Further changes are saved and tracked separately
+ * because they are not part of this commit. This function returns zero in case
+ * of success and a negative error code in case of failure.
+ */
+int ubifs_lpt_start_commit(struct ubifs_info *c)
+{
+	int err, cnt;
+
+	dbg_lp("");
+
+	mutex_lock(&c->lp_mutex);
+	err = dbg_chk_lpt_free_spc(c);
+	if (err)
+		goto out;
+	err = dbg_check_ltab(c);
+	if (err)
+		goto out;
+
+	if (c->check_lpt_free) {
+		/*
+		 * We ensure there is enough free space in
+		 * ubifs_lpt_post_commit() by marking nodes dirty. That
+		 * information is lost when we unmount, so we also need
+		 * to check free space once after mounting also.
+		 */
+		c->check_lpt_free = 0;
+		while (need_write_all(c)) {
+			mutex_unlock(&c->lp_mutex);
+			err = lpt_gc(c);
+			if (err)
+				return err;
+			mutex_lock(&c->lp_mutex);
+		}
+	}
+
+	lpt_tgc_start(c);
+
+	if (!c->dirty_pn_cnt) {
+		dbg_cmt("no cnodes to commit");
+		err = 0;
+		goto out;
+	}
+
+	if (!c->big_lpt && need_write_all(c)) {
+		/* If needed, write everything */
+		err = make_tree_dirty(c);
+		if (err)
+			goto out;
+		lpt_tgc_start(c);
+	}
+
+	if (c->big_lpt)
+		populate_lsave(c);
+
+	cnt = get_cnodes_to_commit(c);
+	ubifs_assert(c, cnt != 0);
+
+	err = layout_cnodes(c);
+	if (err)
+		goto out;
+
+	err = ubifs_lpt_calc_hash(c, c->mst_node->hash_lpt);
+	if (err)
+		goto out;
+
+	/* Copy the LPT's own lprops for end commit to write */
+	memcpy(c->ltab_cmt, c->ltab,
+	       sizeof(struct ubifs_lpt_lprops) * c->lpt_lebs);
+	c->lpt_drty_flgs &= ~(LTAB_DIRTY | LSAVE_DIRTY);
+
+out:
+	mutex_unlock(&c->lp_mutex);
+	return err;
+}
+
+/**
+ * free_obsolete_cnodes - free obsolete cnodes for commit end.
+ * @c: UBIFS file-system description object
+ */
+static void free_obsolete_cnodes(struct ubifs_info *c)
+{
+	struct ubifs_cnode *cnode, *cnext;
+
+	cnext = c->lpt_cnext;
+	if (!cnext)
+		return;
+	do {
+		cnode = cnext;
+		cnext = cnode->cnext;
+		if (test_bit(OBSOLETE_CNODE, &cnode->flags))
+			kfree(cnode);
+		else
+			cnode->cnext = NULL;
+	} while (cnext != c->lpt_cnext);
+	c->lpt_cnext = NULL;
+}
+
+/**
+ * ubifs_lpt_end_commit - finish the commit operation.
+ * @c: the UBIFS file-system description object
+ *
+ * This function has to be called when the commit operation finishes. It
+ * flushes the changes which were "frozen" by 'ubifs_lprops_start_commit()' to
+ * the media. Returns zero in case of success and a negative error code in case
+ * of failure.
+ */
+int ubifs_lpt_end_commit(struct ubifs_info *c)
+{
+	int err;
+
+	dbg_lp("");
+
+	if (!c->lpt_cnext)
+		return 0;
+
+	err = write_cnodes(c);
+	if (err)
+		return err;
+
+	mutex_lock(&c->lp_mutex);
+	free_obsolete_cnodes(c);
+	mutex_unlock(&c->lp_mutex);
+
+	return 0;
+}
+
+/**
+ * ubifs_lpt_post_commit - post commit LPT trivial GC and LPT GC.
+ * @c: UBIFS file-system description object
+ *
+ * LPT trivial GC is completed after a commit. Also LPT GC is done after a
+ * commit for the "big" LPT model.
+ */
+int ubifs_lpt_post_commit(struct ubifs_info *c)
+{
+	int err;
+
+	mutex_lock(&c->lp_mutex);
+	err = lpt_tgc_end(c);
+	if (err)
+		goto out;
+	if (c->big_lpt)
+		while (need_write_all(c)) {
+			mutex_unlock(&c->lp_mutex);
+			err = lpt_gc(c);
+			if (err)
+				return err;
+			mutex_lock(&c->lp_mutex);
+		}
+out:
+	mutex_unlock(&c->lp_mutex);
+	return err;
+}
+
+/**
+ * first_nnode - find the first nnode in memory.
+ * @c: UBIFS file-system description object
+ * @hght: height of tree where nnode found is returned here
+ *
+ * This function returns a pointer to the nnode found or %NULL if no nnode is
+ * found. This function is a helper to 'ubifs_lpt_free()'.
+ */
+static struct ubifs_nnode *first_nnode(struct ubifs_info *c, int *hght)
+{
+	struct ubifs_nnode *nnode;
+	int h, i, found;
+
+	nnode = c->nroot;
+	*hght = 0;
+	if (!nnode)
+		return NULL;
+	for (h = 1; h < c->lpt_hght; h++) {
+		found = 0;
+		for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+			if (nnode->nbranch[i].nnode) {
+				found = 1;
+				nnode = nnode->nbranch[i].nnode;
+				*hght = h;
+				break;
+			}
+		}
+		if (!found)
+			break;
+	}
+	return nnode;
+}
+
+/**
+ * next_nnode - find the next nnode in memory.
+ * @c: UBIFS file-system description object
+ * @nnode: nnode from which to start.
+ * @hght: height of tree where nnode is, is passed and returned here
+ *
+ * This function returns a pointer to the nnode found or %NULL if no nnode is
+ * found. This function is a helper to 'ubifs_lpt_free()'.
+ */
+static struct ubifs_nnode *next_nnode(struct ubifs_info *c,
+				      struct ubifs_nnode *nnode, int *hght)
+{
+	struct ubifs_nnode *parent;
+	int iip, h, i, found;
+
+	parent = nnode->parent;
+	if (!parent)
+		return NULL;
+	if (nnode->iip == UBIFS_LPT_FANOUT - 1) {
+		*hght -= 1;
+		return parent;
+	}
+	for (iip = nnode->iip + 1; iip < UBIFS_LPT_FANOUT; iip++) {
+		nnode = parent->nbranch[iip].nnode;
+		if (nnode)
+			break;
+	}
+	if (!nnode) {
+		*hght -= 1;
+		return parent;
+	}
+	for (h = *hght + 1; h < c->lpt_hght; h++) {
+		found = 0;
+		for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+			if (nnode->nbranch[i].nnode) {
+				found = 1;
+				nnode = nnode->nbranch[i].nnode;
+				*hght = h;
+				break;
+			}
+		}
+		if (!found)
+			break;
+	}
+	return nnode;
+}
+
+/**
+ * ubifs_lpt_free - free resources owned by the LPT.
+ * @c: UBIFS file-system description object
+ * @wr_only: free only resources used for writing
+ */
+void ubifs_lpt_free(struct ubifs_info *c, int wr_only)
+{
+	struct ubifs_nnode *nnode;
+	int i, hght;
+
+	/* Free write-only things first */
+
+	free_obsolete_cnodes(c); /* Leftover from a failed commit */
+
+	vfree(c->ltab_cmt);
+	c->ltab_cmt = NULL;
+	vfree(c->lpt_buf);
+	c->lpt_buf = NULL;
+	kfree(c->lsave);
+	c->lsave = NULL;
+
+	if (wr_only)
+		return;
+
+	/* Now free the rest */
+
+	nnode = first_nnode(c, &hght);
+	while (nnode) {
+		for (i = 0; i < UBIFS_LPT_FANOUT; i++)
+			kfree(nnode->nbranch[i].nnode);
+		nnode = next_nnode(c, nnode, &hght);
+	}
+	for (i = 0; i < LPROPS_HEAP_CNT; i++)
+		kfree(c->lpt_heap[i].arr);
+	kfree(c->dirty_idx.arr);
+	kfree(c->nroot);
+	vfree(c->ltab);
+	kfree(c->lpt_nod_buf);
+}
+
+/*
+ * Everything below is related to debugging.
+ */
+
+/**
+ * dbg_is_all_ff - determine if a buffer contains only 0xFF bytes.
+ * @buf: buffer
+ * @len: buffer length
+ */
+static int dbg_is_all_ff(uint8_t *buf, int len)
+{
+	int i;
+
+	for (i = 0; i < len; i++)
+		if (buf[i] != 0xff)
+			return 0;
+	return 1;
+}
+
+/**
+ * dbg_is_nnode_dirty - determine if a nnode is dirty.
+ * @c: the UBIFS file-system description object
+ * @lnum: LEB number where nnode was written
+ * @offs: offset where nnode was written
+ */
+static int dbg_is_nnode_dirty(struct ubifs_info *c, int lnum, int offs)
+{
+	struct ubifs_nnode *nnode;
+	int hght;
+
+	/* Entire tree is in memory so first_nnode / next_nnode are OK */
+	nnode = first_nnode(c, &hght);
+	for (; nnode; nnode = next_nnode(c, nnode, &hght)) {
+		struct ubifs_nbranch *branch;
+
+		cond_resched();
+		if (nnode->parent) {
+			branch = &nnode->parent->nbranch[nnode->iip];
+			if (branch->lnum != lnum || branch->offs != offs)
+				continue;
+			if (test_bit(DIRTY_CNODE, &nnode->flags))
+				return 1;
+			return 0;
+		} else {
+			if (c->lpt_lnum != lnum || c->lpt_offs != offs)
+				continue;
+			if (test_bit(DIRTY_CNODE, &nnode->flags))
+				return 1;
+			return 0;
+		}
+	}
+	return 1;
+}
+
+/**
+ * dbg_is_pnode_dirty - determine if a pnode is dirty.
+ * @c: the UBIFS file-system description object
+ * @lnum: LEB number where pnode was written
+ * @offs: offset where pnode was written
+ */
+static int dbg_is_pnode_dirty(struct ubifs_info *c, int lnum, int offs)
+{
+	int i, cnt;
+
+	cnt = DIV_ROUND_UP(c->main_lebs, UBIFS_LPT_FANOUT);
+	for (i = 0; i < cnt; i++) {
+		struct ubifs_pnode *pnode;
+		struct ubifs_nbranch *branch;
+
+		cond_resched();
+		pnode = ubifs_pnode_lookup(c, i);
+		if (IS_ERR(pnode))
+			return PTR_ERR(pnode);
+		branch = &pnode->parent->nbranch[pnode->iip];
+		if (branch->lnum != lnum || branch->offs != offs)
+			continue;
+		if (test_bit(DIRTY_CNODE, &pnode->flags))
+			return 1;
+		return 0;
+	}
+	return 1;
+}
+
+/**
+ * dbg_is_ltab_dirty - determine if a ltab node is dirty.
+ * @c: the UBIFS file-system description object
+ * @lnum: LEB number where ltab node was written
+ * @offs: offset where ltab node was written
+ */
+static int dbg_is_ltab_dirty(struct ubifs_info *c, int lnum, int offs)
+{
+	if (lnum != c->ltab_lnum || offs != c->ltab_offs)
+		return 1;
+	return (c->lpt_drty_flgs & LTAB_DIRTY) != 0;
+}
+
+/**
+ * dbg_is_lsave_dirty - determine if a lsave node is dirty.
+ * @c: the UBIFS file-system description object
+ * @lnum: LEB number where lsave node was written
+ * @offs: offset where lsave node was written
+ */
+static int dbg_is_lsave_dirty(struct ubifs_info *c, int lnum, int offs)
+{
+	if (lnum != c->lsave_lnum || offs != c->lsave_offs)
+		return 1;
+	return (c->lpt_drty_flgs & LSAVE_DIRTY) != 0;
+}
+
+/**
+ * dbg_is_node_dirty - determine if a node is dirty.
+ * @c: the UBIFS file-system description object
+ * @node_type: node type
+ * @lnum: LEB number where node was written
+ * @offs: offset where node was written
+ */
+static int dbg_is_node_dirty(struct ubifs_info *c, int node_type, int lnum,
+			     int offs)
+{
+	switch (node_type) {
+	case UBIFS_LPT_NNODE:
+		return dbg_is_nnode_dirty(c, lnum, offs);
+	case UBIFS_LPT_PNODE:
+		return dbg_is_pnode_dirty(c, lnum, offs);
+	case UBIFS_LPT_LTAB:
+		return dbg_is_ltab_dirty(c, lnum, offs);
+	case UBIFS_LPT_LSAVE:
+		return dbg_is_lsave_dirty(c, lnum, offs);
+	}
+	return 1;
+}
+
+/**
+ * dbg_check_ltab_lnum - check the ltab for a LPT LEB number.
+ * @c: the UBIFS file-system description object
+ * @lnum: LEB number where node was written
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int dbg_check_ltab_lnum(struct ubifs_info *c, int lnum)
+{
+	int err, len = c->leb_size, dirty = 0, node_type, node_num, node_len;
+	int ret;
+	void *buf, *p;
+
+	if (!dbg_is_chk_lprops(c))
+		return 0;
+
+	buf = p = __vmalloc(c->leb_size, GFP_NOFS);
+	if (!buf) {
+		ubifs_err(c, "cannot allocate memory for ltab checking");
+		return 0;
+	}
+
+	dbg_lp("LEB %d", lnum);
+
+	err = ubifs_leb_read(c, lnum, buf, 0, c->leb_size, 1);
+	if (err)
+		goto out;
+
+	while (1) {
+		if (!is_a_node(c, p, len)) {
+			int i, pad_len;
+
+			pad_len = get_pad_len(c, p, len);
+			if (pad_len) {
+				p += pad_len;
+				len -= pad_len;
+				dirty += pad_len;
+				continue;
+			}
+			if (!dbg_is_all_ff(p, len)) {
+				ubifs_err(c, "invalid empty space in LEB %d at %d",
+					  lnum, c->leb_size - len);
+				err = -EINVAL;
+			}
+			i = lnum - c->lpt_first;
+			if (len != c->ltab[i].free) {
+				ubifs_err(c, "invalid free space in LEB %d (free %d, expected %d)",
+					  lnum, len, c->ltab[i].free);
+				err = -EINVAL;
+			}
+			if (dirty != c->ltab[i].dirty) {
+				ubifs_err(c, "invalid dirty space in LEB %d (dirty %d, expected %d)",
+					  lnum, dirty, c->ltab[i].dirty);
+				err = -EINVAL;
+			}
+			goto out;
+		}
+		node_type = get_lpt_node_type(c, p, &node_num);
+		node_len = get_lpt_node_len(c, node_type);
+		ret = dbg_is_node_dirty(c, node_type, lnum, c->leb_size - len);
+		if (ret == 1)
+			dirty += node_len;
+		p += node_len;
+		len -= node_len;
+	}
+
+out:
+	vfree(buf);
+	return err;
+}
+
+/**
+ * dbg_check_ltab - check the free and dirty space in the ltab.
+ * @c: the UBIFS file-system description object
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int dbg_check_ltab(struct ubifs_info *c)
+{
+	int lnum, err, i, cnt;
+
+	if (!dbg_is_chk_lprops(c))
+		return 0;
+
+	/* Bring the entire tree into memory */
+	cnt = DIV_ROUND_UP(c->main_lebs, UBIFS_LPT_FANOUT);
+	for (i = 0; i < cnt; i++) {
+		struct ubifs_pnode *pnode;
+
+		pnode = ubifs_pnode_lookup(c, i);
+		if (IS_ERR(pnode))
+			return PTR_ERR(pnode);
+		cond_resched();
+	}
+
+	/* Check nodes */
+	err = dbg_check_lpt_nodes(c, (struct ubifs_cnode *)c->nroot, 0, 0);
+	if (err)
+		return err;
+
+	/* Check each LEB */
+	for (lnum = c->lpt_first; lnum <= c->lpt_last; lnum++) {
+		err = dbg_check_ltab_lnum(c, lnum);
+		if (err) {
+			ubifs_err(c, "failed at LEB %d", lnum);
+			return err;
+		}
+	}
+
+	dbg_lp("succeeded");
+	return 0;
+}
+
+/**
+ * dbg_chk_lpt_free_spc - check LPT free space is enough to write entire LPT.
+ * @c: the UBIFS file-system description object
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int dbg_chk_lpt_free_spc(struct ubifs_info *c)
+{
+	long long free = 0;
+	int i;
+
+	if (!dbg_is_chk_lprops(c))
+		return 0;
+
+	for (i = 0; i < c->lpt_lebs; i++) {
+		if (c->ltab[i].tgc || c->ltab[i].cmt)
+			continue;
+		if (i + c->lpt_first == c->nhead_lnum)
+			free += c->leb_size - c->nhead_offs;
+		else if (c->ltab[i].free == c->leb_size)
+			free += c->leb_size;
+	}
+	if (free < c->lpt_sz) {
+		ubifs_err(c, "LPT space error: free %lld lpt_sz %lld",
+			  free, c->lpt_sz);
+		ubifs_dump_lpt_info(c);
+		ubifs_dump_lpt_lebs(c);
+		dump_stack();
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/**
+ * dbg_chk_lpt_sz - check LPT does not write more than LPT size.
+ * @c: the UBIFS file-system description object
+ * @action: what to do
+ * @len: length written
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ * The @action argument may be one of:
+ *   o %0 - LPT debugging checking starts, initialize debugging variables;
+ *   o %1 - wrote an LPT node, increase LPT size by @len bytes;
+ *   o %2 - switched to a different LEB and wasted @len bytes;
+ *   o %3 - check that we've written the right number of bytes.
+ *   o %4 - wasted @len bytes;
+ */
+int dbg_chk_lpt_sz(struct ubifs_info *c, int action, int len)
+{
+	struct ubifs_debug_info *d = c->dbg;
+	long long chk_lpt_sz, lpt_sz;
+	int err = 0;
+
+	if (!dbg_is_chk_lprops(c))
+		return 0;
+
+	switch (action) {
+	case 0:
+		d->chk_lpt_sz = 0;
+		d->chk_lpt_sz2 = 0;
+		d->chk_lpt_lebs = 0;
+		d->chk_lpt_wastage = 0;
+		if (c->dirty_pn_cnt > c->pnode_cnt) {
+			ubifs_err(c, "dirty pnodes %d exceed max %d",
+				  c->dirty_pn_cnt, c->pnode_cnt);
+			err = -EINVAL;
+		}
+		if (c->dirty_nn_cnt > c->nnode_cnt) {
+			ubifs_err(c, "dirty nnodes %d exceed max %d",
+				  c->dirty_nn_cnt, c->nnode_cnt);
+			err = -EINVAL;
+		}
+		return err;
+	case 1:
+		d->chk_lpt_sz += len;
+		return 0;
+	case 2:
+		d->chk_lpt_sz += len;
+		d->chk_lpt_wastage += len;
+		d->chk_lpt_lebs += 1;
+		return 0;
+	case 3:
+		chk_lpt_sz = c->leb_size;
+		chk_lpt_sz *= d->chk_lpt_lebs;
+		chk_lpt_sz += len - c->nhead_offs;
+		if (d->chk_lpt_sz != chk_lpt_sz) {
+			ubifs_err(c, "LPT wrote %lld but space used was %lld",
+				  d->chk_lpt_sz, chk_lpt_sz);
+			err = -EINVAL;
+		}
+		if (d->chk_lpt_sz > c->lpt_sz) {
+			ubifs_err(c, "LPT wrote %lld but lpt_sz is %lld",
+				  d->chk_lpt_sz, c->lpt_sz);
+			err = -EINVAL;
+		}
+		if (d->chk_lpt_sz2 && d->chk_lpt_sz != d->chk_lpt_sz2) {
+			ubifs_err(c, "LPT layout size %lld but wrote %lld",
+				  d->chk_lpt_sz, d->chk_lpt_sz2);
+			err = -EINVAL;
+		}
+		if (d->chk_lpt_sz2 && d->new_nhead_offs != len) {
+			ubifs_err(c, "LPT new nhead offs: expected %d was %d",
+				  d->new_nhead_offs, len);
+			err = -EINVAL;
+		}
+		lpt_sz = (long long)c->pnode_cnt * c->pnode_sz;
+		lpt_sz += (long long)c->nnode_cnt * c->nnode_sz;
+		lpt_sz += c->ltab_sz;
+		if (c->big_lpt)
+			lpt_sz += c->lsave_sz;
+		if (d->chk_lpt_sz - d->chk_lpt_wastage > lpt_sz) {
+			ubifs_err(c, "LPT chk_lpt_sz %lld + waste %lld exceeds %lld",
+				  d->chk_lpt_sz, d->chk_lpt_wastage, lpt_sz);
+			err = -EINVAL;
+		}
+		if (err) {
+			ubifs_dump_lpt_info(c);
+			ubifs_dump_lpt_lebs(c);
+			dump_stack();
+		}
+		d->chk_lpt_sz2 = d->chk_lpt_sz;
+		d->chk_lpt_sz = 0;
+		d->chk_lpt_wastage = 0;
+		d->chk_lpt_lebs = 0;
+		d->new_nhead_offs = len;
+		return err;
+	case 4:
+		d->chk_lpt_sz += len;
+		d->chk_lpt_wastage += len;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+/**
+ * dump_lpt_leb - dump an LPT LEB.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number to dump
+ *
+ * This function dumps an LEB from LPT area. Nodes in this area are very
+ * different to nodes in the main area (e.g., they do not have common headers,
+ * they do not have 8-byte alignments, etc), so we have a separate function to
+ * dump LPT area LEBs. Note, LPT has to be locked by the caller.
+ */
+static void dump_lpt_leb(const struct ubifs_info *c, int lnum)
+{
+	int err, len = c->leb_size, node_type, node_num, node_len, offs;
+	void *buf, *p;
+
+	pr_err("(pid %d) start dumping LEB %d\n", current->pid, lnum);
+	buf = p = __vmalloc(c->leb_size, GFP_NOFS);
+	if (!buf) {
+		ubifs_err(c, "cannot allocate memory to dump LPT");
+		return;
+	}
+
+	err = ubifs_leb_read(c, lnum, buf, 0, c->leb_size, 1);
+	if (err)
+		goto out;
+
+	while (1) {
+		offs = c->leb_size - len;
+		if (!is_a_node(c, p, len)) {
+			int pad_len;
+
+			pad_len = get_pad_len(c, p, len);
+			if (pad_len) {
+				pr_err("LEB %d:%d, pad %d bytes\n",
+				       lnum, offs, pad_len);
+				p += pad_len;
+				len -= pad_len;
+				continue;
+			}
+			if (len)
+				pr_err("LEB %d:%d, free %d bytes\n",
+				       lnum, offs, len);
+			break;
+		}
+
+		node_type = get_lpt_node_type(c, p, &node_num);
+		switch (node_type) {
+		case UBIFS_LPT_PNODE:
+		{
+			node_len = c->pnode_sz;
+			if (c->big_lpt)
+				pr_err("LEB %d:%d, pnode num %d\n",
+				       lnum, offs, node_num);
+			else
+				pr_err("LEB %d:%d, pnode\n", lnum, offs);
+			break;
+		}
+		case UBIFS_LPT_NNODE:
+		{
+			int i;
+			struct ubifs_nnode nnode;
+
+			node_len = c->nnode_sz;
+			if (c->big_lpt)
+				pr_err("LEB %d:%d, nnode num %d, ",
+				       lnum, offs, node_num);
+			else
+				pr_err("LEB %d:%d, nnode, ",
+				       lnum, offs);
+			err = ubifs_unpack_nnode(c, p, &nnode);
+			if (err) {
+				pr_err("failed to unpack_node, error %d\n",
+				       err);
+				break;
+			}
+			for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+				pr_cont("%d:%d", nnode.nbranch[i].lnum,
+				       nnode.nbranch[i].offs);
+				if (i != UBIFS_LPT_FANOUT - 1)
+					pr_cont(", ");
+			}
+			pr_cont("\n");
+			break;
+		}
+		case UBIFS_LPT_LTAB:
+			node_len = c->ltab_sz;
+			pr_err("LEB %d:%d, ltab\n", lnum, offs);
+			break;
+		case UBIFS_LPT_LSAVE:
+			node_len = c->lsave_sz;
+			pr_err("LEB %d:%d, lsave len\n", lnum, offs);
+			break;
+		default:
+			ubifs_err(c, "LPT node type %d not recognized", node_type);
+			goto out;
+		}
+
+		p += node_len;
+		len -= node_len;
+	}
+
+	pr_err("(pid %d) finish dumping LEB %d\n", current->pid, lnum);
+out:
+	vfree(buf);
+}
+
+/**
+ * ubifs_dump_lpt_lebs - dump LPT lebs.
+ * @c: UBIFS file-system description object
+ *
+ * This function dumps all LPT LEBs. The caller has to make sure the LPT is
+ * locked.
+ */
+void ubifs_dump_lpt_lebs(const struct ubifs_info *c)
+{
+	int i;
+
+	pr_err("(pid %d) start dumping all LPT LEBs\n", current->pid);
+	for (i = 0; i < c->lpt_lebs; i++)
+		dump_lpt_leb(c, i + c->lpt_first);
+	pr_err("(pid %d) finish dumping all LPT LEBs\n", current->pid);
+}
+
+/**
+ * dbg_populate_lsave - debugging version of 'populate_lsave()'
+ * @c: UBIFS file-system description object
+ *
+ * This is a debugging version for 'populate_lsave()' which populates lsave
+ * with random LEBs instead of useful LEBs, which is good for test coverage.
+ * Returns zero if lsave has not been populated (this debugging feature is
+ * disabled) an non-zero if lsave has been populated.
+ */
+static int dbg_populate_lsave(struct ubifs_info *c)
+{
+	struct ubifs_lprops *lprops;
+	struct ubifs_lpt_heap *heap;
+	int i;
+
+	if (!dbg_is_chk_gen(c))
+		return 0;
+	if (get_random_u32_below(4))
+		return 0;
+
+	for (i = 0; i < c->lsave_cnt; i++)
+		c->lsave[i] = c->main_first;
+
+	list_for_each_entry(lprops, &c->empty_list, list)
+		c->lsave[get_random_u32_below(c->lsave_cnt)] = lprops->lnum;
+	list_for_each_entry(lprops, &c->freeable_list, list)
+		c->lsave[get_random_u32_below(c->lsave_cnt)] = lprops->lnum;
+	list_for_each_entry(lprops, &c->frdi_idx_list, list)
+		c->lsave[get_random_u32_below(c->lsave_cnt)] = lprops->lnum;
+
+	heap = &c->lpt_heap[LPROPS_DIRTY_IDX - 1];
+	for (i = 0; i < heap->cnt; i++)
+		c->lsave[get_random_u32_below(c->lsave_cnt)] = heap->arr[i]->lnum;
+	heap = &c->lpt_heap[LPROPS_DIRTY - 1];
+	for (i = 0; i < heap->cnt; i++)
+		c->lsave[get_random_u32_below(c->lsave_cnt)] = heap->arr[i]->lnum;
+	heap = &c->lpt_heap[LPROPS_FREE - 1];
+	for (i = 0; i < heap->cnt; i++)
+		c->lsave[get_random_u32_below(c->lsave_cnt)] = heap->arr[i]->lnum;
+
+	return 1;
+}