ubifs: update implementation from u-boot v2016.03

This updated code supports recovering from unclean unmounts when write
buffer size is larger than 8. Linux uses takes information into
consideration when checking for writes.
The following list shows the changes for each file done compared to
u-boot v2016.03 code.

Makefile
* Add gc.o, do not include header as in u-boot

budget.c:
* Replace __UBOOT__ with __BAREBOX__

debug.c:
* Replace __UBOOT__ with __BAREBOX__
* Remove #include <linux/compat.h>
* Replace current->pid with 0

debug.h
* Replace __UBOOT__ with __BAREBOX__
* Add "0 &&" to ubifs_assert condition check
  U-Boot essentially disabled pr_crit output and dump_stack() is defined
  to do { } while (0), so ubifs_assert does nothing despite condition.

gc.c:
* Replace __UBOOT__ with __BAREBOX__

io.c:
* Replace __UBOOT__ with __BAREBOX__
* Remove #include <linux/compat.h>

key.h:
* No changes

log.c:
* No changes

lprops.c:
* Replace __UBOOT__ with __BAREBOX__

lpt.c
* Replace __UBOOT__ with __BAREBOX__
* Remove #include <linux/compat.h>
* Remove #include <ubi_uboot.h>

lpt_commit.c
* Replace __UBOOT__ with __BAREBOX__
* Remove #include <linux/compat.h>

master.c
* Replace __UBOOT__ with __BAREBOX__
* Remove #include <linux/compat.h>
* Remove #include <ubi_uboot.h>

misc.h
* Replace __UBOOT__ with __BAREBOX__
* Add #ifndef __BAREBOX__ around unneeded ubifs_current_time

orphan.c
* No changes

recovery.c
* Replace __UBOOT__ with __BAREBOX__

replay.c
* Replace __UBOOT__ with __BAREBOX__
* Remove #include <linux/compat.h>

sb.c
* Replace __UBOOT__ with __BAREBOX__
* Remove #include <linux/compat.h>
* Remove #include <ubi_uboot.h>
* rp_uid and rp_gid are still uid_t, not kuid_t, so remove .val

scan.c
* Replace __UBOOT__ with __BAREBOX__

super.c:
* Replaced current->pid with 0
* Replaced __UBOOT__ with __BAREBOX__
* Removed #include <ubi_uboot.h>
* Removed #include <memalign.h>
* Added #include <init.h>
* Replaced malloc_cache_aligned with kzalloc
* Replaced I_LOCK with I_SYNC
* i_uid and i_gid are still uid_t, not kuid_t, so remove .val
* Replaced string "U-Boot" with "Barebox"
* Add #ifndef __BAREBOX__ around open_ubi, sb_test, sb_set, ubifs_mount,
  kill_ubifs_super, ubifs_fs_type
* Do not call ubi_open_volume or ubi_close_volume in ubifs_fill_super
  Those will already be handled in ubifs_probe
* Replaced uboot_ubifs_mount with new ubifs_get_super implementation using
  existing functions alloc_super, alloc_ubifs_info

tnc.c
* Replace __UBOOT__ with __BAREBOX__
* Remove #include <linux/compat.h>

tnc_misc.c
* Replace __UBOOT__ with __BAREBOX__

ubifs-media.h
* Replace __UBOOT__ with __BAREBOX__

ubifs.c:
* Replaced __UBOOT__ with __BAREBOX__
* Adjusted header includes
* Removed DECLARE_GLOBAL_DATA_PTR
* Add static struct z_stream_s variable
* Add struct ubifs_priv delcaration
* Replaced zunzip with deflate_decompress call
* Add ifdef for disabling ZLIB and/or LZO support
* Replaced malloc_cache_aligned with kzalloc
* Added #ifndef __BAREBOX__ around filldir, ubifs_printdir,
  ubifs_set_blk_dev, ubifs_ls, ubifs_exists, ubifs_size, do_readpage,
  ubifs_read, ubifs_close, ubifs_load
* Make parameter filename const char* in ubifs_findfile
* Add UBIFS fs_driver_d implementation
* Add zlib_decomp_init, ubifs_init

ubifs.h:
* Replaced __UBOOT__ with __BAREBOX__
* Adjusted header includes
* Added old #define crc32
* Added helper around kmem*
* Added XATTR_LIST_MAX define
* Added #ifndef __BAREBOX__ around current_fs_time struct inode,
  struct super_block, file_system_type, dentry and friends which barebox
  already has
* Added #ifndef __BAREBOX__ around write_inode in super_operations to avoid
  declaration of writeback_control
* Change rp_uid and rp_gid to uid_t and gui_t
* Added struct device_d to struct ubifs_info
* Added forward declaration of ubifs_get_super

linux/fs.h:
* Make struct inode's i_nlink a union containing a non-const int __i_nlink
  while making i_nlink a const int

linux/fs.h:
* Add s_remove_count

linux/fs.h:
* Convert struct super_block.s_instances and
  struct file_system_type.fs_supers to hlist_head

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 657 insertions, 99 deletions

diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c
index ccda9387bc..73abece321 100644
--- a/fs/ubifs/tnc.c
+++ b/fs/ubifs/tnc.c
@@ -3,18 +3,7 @@
  *
  * Copyright (C) 2006-2008 Nokia Corporation.
  *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along with
- * this program; if not, write to the Free Software Foundation, Inc., 51
- * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ * SPDX-License-Identifier:	GPL-2.0+
  *
  * Authors: Adrian Hunter
  *          Artem Bityutskiy (Битюцкий Артём)
@@ -30,6 +19,13 @@
  * the mutex locked.
  */
 
+#ifndef __BAREBOX__
+#include <linux/crc32.h>
+#include <linux/slab.h>
+#else
+#include <linux/err.h>
+#include <linux/stat.h>
+#endif
 #include "ubifs.h"
 
 /*
@@ -96,7 +92,7 @@ static int insert_old_idx(struct ubifs_info *c, int lnum, int offs)
 		else if (offs > o->offs)
 			p = &(*p)->rb_right;
 		else {
-			ubifs_err("old idx added twice!");
+			ubifs_err(c, "old idx added twice!");
 			kfree(old_idx);
 			return 0;
 		}
@@ -176,27 +172,11 @@ static int ins_clr_old_idx_znode(struct ubifs_info *c,
  */
 void destroy_old_idx(struct ubifs_info *c)
 {
-	struct rb_node *this = c->old_idx.rb_node;
-	struct ubifs_old_idx *old_idx;
+	struct ubifs_old_idx *old_idx, *n;
 
-	while (this) {
-		if (this->rb_left) {
-			this = this->rb_left;
-			continue;
-		} else if (this->rb_right) {
-			this = this->rb_right;
-			continue;
-		}
-		old_idx = rb_entry(this, struct ubifs_old_idx, rb);
-		this = rb_parent(this);
-		if (this) {
-			if (this->rb_left == &old_idx->rb)
-				this->rb_left = NULL;
-			else
-				this->rb_right = NULL;
-		}
+	rbtree_postorder_for_each_entry_safe(old_idx, n, &c->old_idx, rb)
 		kfree(old_idx);
-	}
+
 	c->old_idx = RB_ROOT;
 }
 
@@ -221,7 +201,7 @@ static struct ubifs_znode *copy_znode(struct ubifs_info *c,
 	__set_bit(DIRTY_ZNODE, &zn->flags);
 	__clear_bit(COW_ZNODE, &zn->flags);
 
-	ubifs_assert(!test_bit(OBSOLETE_ZNODE, &znode->flags));
+	ubifs_assert(!ubifs_zn_obsolete(znode));
 	__set_bit(OBSOLETE_ZNODE, &znode->flags);
 
 	if (znode->level != 0) {
@@ -269,7 +249,7 @@ static struct ubifs_znode *dirty_cow_znode(struct ubifs_info *c,
 	struct ubifs_znode *zn;
 	int err;
 
-	if (!test_bit(COW_ZNODE, &znode->flags)) {
+	if (!ubifs_zn_cow(znode)) {
 		/* znode is not being committed */
 		if (!test_and_set_bit(DIRTY_ZNODE, &znode->flags)) {
 			atomic_long_inc(&c->dirty_zn_cnt);
@@ -337,17 +317,16 @@ static int lnc_add(struct ubifs_info *c, struct ubifs_zbranch *zbr,
 
 	err = ubifs_validate_entry(c, dent);
 	if (err) {
-		dbg_dump_stack();
-		dbg_dump_node(c, dent);
+		dump_stack();
+		ubifs_dump_node(c, dent);
 		return err;
 	}
 
-	lnc_node = kmalloc(zbr->len, GFP_NOFS);
+	lnc_node = kmemdup(node, zbr->len, GFP_NOFS);
 	if (!lnc_node)
 		/* We don't have to have the cache, so no error */
 		return 0;
 
-	memcpy(lnc_node, node, zbr->len);
 	zbr->leaf = lnc_node;
 	return 0;
 }
@@ -371,8 +350,8 @@ static int lnc_add_directly(struct ubifs_info *c, struct ubifs_zbranch *zbr,
 
 	err = ubifs_validate_entry(c, node);
 	if (err) {
-		dbg_dump_stack();
-		dbg_dump_node(c, node);
+		dump_stack();
+		ubifs_dump_node(c, node);
 		return err;
 	}
 
@@ -445,8 +424,11 @@ static int tnc_read_node_nm(struct ubifs_info *c, struct ubifs_zbranch *zbr,
  *
  * 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.
+ * @c->mounting or @c->remounting_rw is true (we are mounting or re-mounting to
+ * R/W mode), @c->no_chk_data_crc is ignored and CRC is checked. This is
+ * because during mounting or re-mounting from R/O mode to R/W mode we may read
+ * journal nodes (when replying the journal or doing the recovery) and the
+ * journal nodes may potentially be corrupted, so checking is required.
  */
 static int try_read_node(const struct ubifs_info *c, void *buf, int type,
 			 int len, int lnum, int offs)
@@ -457,9 +439,9 @@ static int try_read_node(const struct ubifs_info *c, void *buf, int type,
 
 	dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
 
-	err = ubi_read(c->ubi, lnum, buf, offs, len);
+	err = ubifs_leb_read(c, lnum, buf, offs, len, 1);
 	if (err) {
-		ubifs_err("cannot read node type %d from LEB %d:%d, error %d",
+		ubifs_err(c, "cannot read node type %d from LEB %d:%d, error %d",
 			  type, lnum, offs, err);
 		return err;
 	}
@@ -474,7 +456,8 @@ 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 && c->no_chk_data_crc)
+	if (type == UBIFS_DATA_NODE && c->no_chk_data_crc && !c->mounting &&
+	    !c->remounting_rw)
 		return 1;
 
 	crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
@@ -500,7 +483,7 @@ static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key,
 {
 	int ret;
 
-	dbg_tnc("LEB %d:%d, key %s", zbr->lnum, zbr->offs, DBGKEY(key));
+	dbg_tnck(key, "LEB %d:%d, key ", zbr->lnum, zbr->offs);
 
 	ret = try_read_node(c, node, key_type(c, key), zbr->len, zbr->lnum,
 			    zbr->offs);
@@ -514,8 +497,8 @@ static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key,
 			ret = 0;
 	}
 	if (ret == 0 && c->replaying)
-		dbg_mnt("dangling branch LEB %d:%d len %d, key %s",
-			zbr->lnum, zbr->offs, zbr->len, DBGKEY(key));
+		dbg_mntk(key, "dangling branch LEB %d:%d len %d, key ",
+			zbr->lnum, zbr->offs, zbr->len);
 	return ret;
 }
 
@@ -990,9 +973,9 @@ static int fallible_resolve_collision(struct ubifs_info *c,
 	if (adding || !o_znode)
 		return 0;
 
-	dbg_mnt("dangling match LEB %d:%d len %d %s",
+	dbg_mntk(key, "dangling match LEB %d:%d len %d key ",
 		o_znode->zbranch[o_n].lnum, o_znode->zbranch[o_n].offs,
-		o_znode->zbranch[o_n].len, DBGKEY(key));
+		o_znode->zbranch[o_n].len);
 	*zn = o_znode;
 	*n = o_n;
 	return 1;
@@ -1158,8 +1141,8 @@ static struct ubifs_znode *dirty_cow_bottom_up(struct ubifs_info *c,
  *   o exact match, i.e. the found zero-level znode contains key @key, then %1
  *     is returned and slot number of the matched branch is stored in @n;
  *   o not exact match, which means that zero-level znode does not contain
- *     @key, then %0 is returned and slot number of the closed branch is stored
- *     in  @n;
+ *     @key, then %0 is returned and slot number of the closest branch is stored
+ *     in @n;
  *   o @key is so small that it is even less than the lowest key of the
  *     leftmost zero-level node, then %0 is returned and %0 is stored in @n.
  *
@@ -1174,7 +1157,8 @@ int ubifs_lookup_level0(struct ubifs_info *c, const union ubifs_key *key,
 	struct ubifs_znode *znode;
 	unsigned long time = get_seconds();
 
-	dbg_tnc("search key %s", DBGKEY(key));
+	dbg_tnck(key, "search key ");
+	ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
 
 	znode = c->zroot.znode;
 	if (unlikely(!znode)) {
@@ -1251,7 +1235,7 @@ int ubifs_lookup_level0(struct ubifs_info *c, const union ubifs_key *key,
 	 * splitting in the middle of the colliding sequence. Also, when
 	 * removing the leftmost key, we would have to correct the key of the
 	 * parent node, which would introduce additional complications. Namely,
-	 * if we changed the the leftmost key of the parent znode, the garbage
+	 * if we changed the leftmost key of the parent znode, the garbage
 	 * collector would be unable to find it (GC is doing this when GC'ing
 	 * indexing LEBs). Although we already have an additional RB-tree where
 	 * we save such changed znodes (see 'ins_clr_old_idx_znode()') until
@@ -1309,7 +1293,7 @@ static int lookup_level0_dirty(struct ubifs_info *c, const union ubifs_key *key,
 	struct ubifs_znode *znode;
 	unsigned long time = get_seconds();
 
-	dbg_tnc("search and dirty key %s", DBGKEY(key));
+	dbg_tnck(key, "search and dirty key ");
 
 	znode = c->zroot.znode;
 	if (unlikely(!znode)) {
@@ -1400,9 +1384,31 @@ static int lookup_level0_dirty(struct ubifs_info *c, const union ubifs_key *key,
  */
 static int maybe_leb_gced(struct ubifs_info *c, int lnum, int gc_seq1)
 {
+#ifndef __BAREBOX__
+	int gc_seq2, gced_lnum;
+
+	gced_lnum = c->gced_lnum;
+	smp_rmb();
+	gc_seq2 = c->gc_seq;
+	/* Same seq means no GC */
+	if (gc_seq1 == gc_seq2)
+		return 0;
+	/* Different by more than 1 means we don't know */
+	if (gc_seq1 + 1 != gc_seq2)
+		return 1;
 	/*
-	 * No garbage collection in the read-only U-Boot implementation
+	 * We have seen the sequence number has increased by 1. Now we need to
+	 * be sure we read the right LEB number, so read it again.
 	 */
+	smp_rmb();
+	if (gced_lnum != c->gced_lnum)
+		return 1;
+	/* Finally we can check lnum */
+	if (gced_lnum == lnum)
+		return 1;
+#else
+	/* No garbage collection in the read-only U-Boot implementation */
+#endif
 	return 0;
 }
 
@@ -1414,7 +1420,7 @@ static int maybe_leb_gced(struct ubifs_info *c, int lnum, int gc_seq1)
  * @lnum: LEB number is returned here
  * @offs: offset is returned here
  *
- * This function look up and reads node with key @key. The caller has to make
+ * This function looks up and reads node with key @key. The caller has to make
  * sure the @node buffer is large enough to fit the node. Returns zero in case
  * of success, %-ENOENT if the node was not found, and a negative error code in
  * case of failure. The node location can be returned in @lnum and @offs.
@@ -1458,6 +1464,12 @@ again:
 	gc_seq1 = c->gc_seq;
 	mutex_unlock(&c->tnc_mutex);
 
+	if (ubifs_get_wbuf(c, zbr.lnum)) {
+		/* We do not GC journal heads */
+		err = ubifs_tnc_read_node(c, &zbr, node);
+		return err;
+	}
+
 	err = fallible_read_node(c, key, &zbr, node);
 	if (err <= 0 || maybe_leb_gced(c, zbr.lnum, gc_seq1)) {
 		/*
@@ -1610,6 +1622,51 @@ out:
 }
 
 /**
+ * read_wbuf - bulk-read from a LEB with a wbuf.
+ * @wbuf: wbuf that may overlap the read
+ * @buf: buffer into which to read
+ * @len: read length
+ * @lnum: LEB number from which to read
+ * @offs: offset from which to read
+ *
+ * This functions returns %0 on success or a negative error code on failure.
+ */
+static int read_wbuf(struct ubifs_wbuf *wbuf, void *buf, int len, int lnum,
+		     int offs)
+{
+	const struct ubifs_info *c = wbuf->c;
+	int rlen, overlap;
+
+	dbg_io("LEB %d:%d, length %d", lnum, offs, len);
+	ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
+	ubifs_assert(!(offs & 7) && offs < c->leb_size);
+	ubifs_assert(offs + len <= c->leb_size);
+
+	spin_lock(&wbuf->lock);
+	overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
+	if (!overlap) {
+		/* We may safely unlock the write-buffer and read the data */
+		spin_unlock(&wbuf->lock);
+		return ubifs_leb_read(c, lnum, buf, offs, len, 0);
+	}
+
+	/* Don't read under wbuf */
+	rlen = wbuf->offs - offs;
+	if (rlen < 0)
+		rlen = 0;
+
+	/* Copy the rest from the write-buffer */
+	memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
+	spin_unlock(&wbuf->lock);
+
+	if (rlen > 0)
+		/* Read everything that goes before write-buffer */
+		return ubifs_leb_read(c, lnum, buf, offs, rlen, 0);
+
+	return 0;
+}
+
+/**
  * validate_data_node - validate data nodes for bulk-read.
  * @c: UBIFS file-system description object
  * @buf: buffer containing data node to validate
@@ -1625,30 +1682,30 @@ static int validate_data_node(struct ubifs_info *c, void *buf,
 	int err, len;
 
 	if (ch->node_type != UBIFS_DATA_NODE) {
-		ubifs_err("bad node type (%d but expected %d)",
+		ubifs_err(c, "bad node type (%d but expected %d)",
 			  ch->node_type, UBIFS_DATA_NODE);
 		goto out_err;
 	}
 
 	err = ubifs_check_node(c, buf, zbr->lnum, zbr->offs, 0, 0);
 	if (err) {
-		ubifs_err("expected node type %d", UBIFS_DATA_NODE);
+		ubifs_err(c, "expected node type %d", UBIFS_DATA_NODE);
 		goto out;
 	}
 
 	len = le32_to_cpu(ch->len);
 	if (len != zbr->len) {
-		ubifs_err("bad node length %d, expected %d", len, zbr->len);
+		ubifs_err(c, "bad node length %d, expected %d", len, zbr->len);
 		goto out_err;
 	}
 
 	/* Make sure the key of the read node is correct */
 	key_read(c, buf + UBIFS_KEY_OFFSET, &key1);
 	if (!keys_eq(c, &zbr->key, &key1)) {
-		ubifs_err("bad key in node at LEB %d:%d",
+		ubifs_err(c, "bad key in node at LEB %d:%d",
 			  zbr->lnum, zbr->offs);
-		dbg_tnc("looked for key %s found node's key %s",
-			DBGKEY(&zbr->key), DBGKEY1(&key1));
+		dbg_tnck(&zbr->key, "looked for key ");
+		dbg_tnck(&key1, "found node's key ");
 		goto out_err;
 	}
 
@@ -1657,9 +1714,9 @@ static int validate_data_node(struct ubifs_info *c, void *buf,
 out_err:
 	err = -EINVAL;
 out:
-	ubifs_err("bad node at LEB %d:%d", zbr->lnum, zbr->offs);
-	dbg_dump_node(c, buf);
-	dbg_dump_stack();
+	ubifs_err(c, "bad node at LEB %d:%d", zbr->lnum, zbr->offs);
+	ubifs_dump_node(c, buf);
+	dump_stack();
 	return err;
 }
 
@@ -1676,27 +1733,32 @@ out:
 int ubifs_tnc_bulk_read(struct ubifs_info *c, struct bu_info *bu)
 {
 	int lnum = bu->zbranch[0].lnum, offs = bu->zbranch[0].offs, len, err, i;
+	struct ubifs_wbuf *wbuf;
 	void *buf;
 
 	len = bu->zbranch[bu->cnt - 1].offs;
 	len += bu->zbranch[bu->cnt - 1].len - offs;
 	if (len > bu->buf_len) {
-		ubifs_err("buffer too small %d vs %d", bu->buf_len, len);
+		ubifs_err(c, "buffer too small %d vs %d", bu->buf_len, len);
 		return -EINVAL;
 	}
 
 	/* Do the read */
-	err = ubi_read(c->ubi, lnum, bu->buf, offs, len);
+	wbuf = ubifs_get_wbuf(c, lnum);
+	if (wbuf)
+		err = read_wbuf(wbuf, bu->buf, len, lnum, offs);
+	else
+		err = ubifs_leb_read(c, lnum, bu->buf, offs, len, 0);
 
 	/* Check for a race with GC */
 	if (maybe_leb_gced(c, lnum, bu->gc_seq))
 		return -EAGAIN;
 
 	if (err && err != -EBADMSG) {
-		ubifs_err("failed to read from LEB %d:%d, error %d",
+		ubifs_err(c, "failed to read from LEB %d:%d, error %d",
 			  lnum, offs, err);
-		dbg_dump_stack();
-		dbg_tnc("key %s", DBGKEY(&bu->key));
+		dump_stack();
+		dbg_tnck(&bu->key, "key ");
 		return err;
 	}
 
@@ -1731,7 +1793,7 @@ static int do_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
 	int found, n, err;
 	struct ubifs_znode *znode;
 
-	dbg_tnc("name '%.*s' key %s", nm->len, nm->name, DBGKEY(key));
+	dbg_tnck(key, "name '%.*s' key ", nm->len, nm->name);
 	mutex_lock(&c->tnc_mutex);
 	found = ubifs_lookup_level0(c, key, &znode, &n);
 	if (!found) {
@@ -1905,8 +1967,7 @@ again:
 	zp = znode->parent;
 	if (znode->child_cnt < c->fanout) {
 		ubifs_assert(n != c->fanout);
-		dbg_tnc("inserted at %d level %d, key %s", n, znode->level,
-			DBGKEY(key));
+		dbg_tnck(key, "inserted at %d level %d, key ", n, znode->level);
 
 		insert_zbranch(znode, zbr, n);
 
@@ -1921,7 +1982,7 @@ again:
 	 * Unfortunately, @znode does not have more empty slots and we have to
 	 * split it.
 	 */
-	dbg_tnc("splitting level %d, key %s", znode->level, DBGKEY(key));
+	dbg_tnck(key, "splitting level %d, key ", znode->level);
 
 	if (znode->alt)
 		/*
@@ -2015,7 +2076,7 @@ do_split:
 	}
 
 	/* Insert new key and branch */
-	dbg_tnc("inserting at %d level %d, key %s", n, zn->level, DBGKEY(key));
+	dbg_tnck(key, "inserting at %d level %d, key ", n, zn->level);
 
 	insert_zbranch(zi, zbr, n);
 
@@ -2091,7 +2152,7 @@ int ubifs_tnc_add(struct ubifs_info *c, const union ubifs_key *key, int lnum,
 	struct ubifs_znode *znode;
 
 	mutex_lock(&c->tnc_mutex);
-	dbg_tnc("%d:%d, len %d, key %s", lnum, offs, len, DBGKEY(key));
+	dbg_tnck(key, "%d:%d, len %d, key ", lnum, offs, len);
 	found = lookup_level0_dirty(c, key, &znode, &n);
 	if (!found) {
 		struct ubifs_zbranch zbr;
@@ -2140,8 +2201,8 @@ int ubifs_tnc_replace(struct ubifs_info *c, const union ubifs_key *key,
 	struct ubifs_znode *znode;
 
 	mutex_lock(&c->tnc_mutex);
-	dbg_tnc("old LEB %d:%d, new LEB %d:%d, len %d, key %s", old_lnum,
-		old_offs, lnum, offs, len, DBGKEY(key));
+	dbg_tnck(key, "old LEB %d:%d, new LEB %d:%d, len %d, key ", old_lnum,
+		 old_offs, lnum, offs, len);
 	found = lookup_level0_dirty(c, key, &znode, &n);
 	if (found < 0) {
 		err = found;
@@ -2223,8 +2284,8 @@ int ubifs_tnc_add_nm(struct ubifs_info *c, const union ubifs_key *key,
 	struct ubifs_znode *znode;
 
 	mutex_lock(&c->tnc_mutex);
-	dbg_tnc("LEB %d:%d, name '%.*s', key %s", lnum, offs, nm->len, nm->name,
-		DBGKEY(key));
+	dbg_tnck(key, "LEB %d:%d, name '%.*s', key ",
+		 lnum, offs, nm->len, nm->name);
 	found = lookup_level0_dirty(c, key, &znode, &n);
 	if (found < 0) {
 		err = found;
@@ -2282,7 +2343,7 @@ int ubifs_tnc_add_nm(struct ubifs_info *c, const union ubifs_key *key,
 			 * by passing 'ubifs_tnc_remove_nm()' the same key but
 			 * an unmatchable name.
 			 */
-			struct qstr noname = { .len = 0, .name = "" };
+			struct qstr noname = { .name = "" };
 
 			err = dbg_check_tnc(c, 0);
 			mutex_unlock(&c->tnc_mutex);
@@ -2317,14 +2378,14 @@ static int tnc_delete(struct ubifs_info *c, struct ubifs_znode *znode, int n)
 	/* Delete without merge for now */
 	ubifs_assert(znode->level == 0);
 	ubifs_assert(n >= 0 && n < c->fanout);
-	dbg_tnc("deleting %s", DBGKEY(&znode->zbranch[n].key));
+	dbg_tnck(&znode->zbranch[n].key, "deleting key ");
 
 	zbr = &znode->zbranch[n];
 	lnc_free(zbr);
 
 	err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
 	if (err) {
-		dbg_dump_znode(c, znode);
+		ubifs_dump_znode(c, znode);
 		return err;
 	}
 
@@ -2342,7 +2403,7 @@ static int tnc_delete(struct ubifs_info *c, struct ubifs_znode *znode, int n)
 	 */
 
 	do {
-		ubifs_assert(!test_bit(OBSOLETE_ZNODE, &znode->flags));
+		ubifs_assert(!ubifs_zn_obsolete(znode));
 		ubifs_assert(ubifs_zn_dirty(znode));
 
 		zp = znode->parent;
@@ -2398,9 +2459,8 @@ static int tnc_delete(struct ubifs_info *c, struct ubifs_znode *znode, int n)
 			c->zroot.offs = zbr->offs;
 			c->zroot.len = zbr->len;
 			c->zroot.znode = znode;
-			ubifs_assert(!test_bit(OBSOLETE_ZNODE,
-				     &zp->flags));
-			ubifs_assert(test_bit(DIRTY_ZNODE, &zp->flags));
+			ubifs_assert(!ubifs_zn_obsolete(zp));
+			ubifs_assert(ubifs_zn_dirty(zp));
 			atomic_long_dec(&c->dirty_zn_cnt);
 
 			if (zp->cnext) {
@@ -2428,7 +2488,7 @@ int ubifs_tnc_remove(struct ubifs_info *c, const union ubifs_key *key)
 	struct ubifs_znode *znode;
 
 	mutex_lock(&c->tnc_mutex);
-	dbg_tnc("key %s", DBGKEY(key));
+	dbg_tnck(key, "key ");
 	found = lookup_level0_dirty(c, key, &znode, &n);
 	if (found < 0) {
 		err = found;
@@ -2459,7 +2519,7 @@ int ubifs_tnc_remove_nm(struct ubifs_info *c, const union ubifs_key *key,
 	struct ubifs_znode *znode;
 
 	mutex_lock(&c->tnc_mutex);
-	dbg_tnc("%.*s, key %s", nm->len, nm->name, DBGKEY(key));
+	dbg_tnck(key, "%.*s, key ", nm->len, nm->name);
 	err = lookup_level0_dirty(c, key, &znode, &n);
 	if (err < 0)
 		goto out_unlock;
@@ -2476,11 +2536,11 @@ int ubifs_tnc_remove_nm(struct ubifs_info *c, const union ubifs_key *key,
 		if (err) {
 			/* Ensure the znode is dirtied */
 			if (znode->cnext || !ubifs_zn_dirty(znode)) {
-				    znode = dirty_cow_bottom_up(c, znode);
-				    if (IS_ERR(znode)) {
-					    err = PTR_ERR(znode);
-					    goto out_unlock;
-				    }
+				znode = dirty_cow_bottom_up(c, znode);
+				if (IS_ERR(znode)) {
+					err = PTR_ERR(znode);
+					goto out_unlock;
+				}
 			}
 			err = tnc_delete(c, znode, n);
 		}
@@ -2571,10 +2631,10 @@ int ubifs_tnc_remove_range(struct ubifs_info *c, union ubifs_key *from_key,
 			err = ubifs_add_dirt(c, znode->zbranch[i].lnum,
 					     znode->zbranch[i].len);
 			if (err) {
-				dbg_dump_znode(c, znode);
+				ubifs_dump_znode(c, znode);
 				goto out_unlock;
 			}
-			dbg_tnc("removing %s", DBGKEY(key));
+			dbg_tnck(key, "removing key ");
 		}
 		if (k) {
 			for (i = n + 1 + k; i < znode->child_cnt; i++)
@@ -2633,7 +2693,7 @@ int ubifs_tnc_remove_ino(struct ubifs_info *c, ino_t inum)
 		dbg_tnc("xent '%s', ino %lu", xent->name,
 			(unsigned long)xattr_inum);
 
-		nm.name = (char *)xent->name;
+		nm.name = xent->name;
 		nm.len = le16_to_cpu(xent->nlen);
 		err = ubifs_tnc_remove_nm(c, &key1, &nm);
 		if (err) {
@@ -2694,7 +2754,7 @@ struct ubifs_dent_node *ubifs_tnc_next_ent(struct ubifs_info *c,
 	struct ubifs_zbranch *zbr;
 	union ubifs_key *dkey;
 
-	dbg_tnc("%s %s", nm->name ? (char *)nm->name : "(lowest)", DBGKEY(key));
+	dbg_tnck(key, "%s ", nm->name ? (char *)nm->name : "(lowest)");
 	ubifs_assert(is_hash_key(c, key));
 
 	mutex_lock(&c->tnc_mutex);
@@ -2765,3 +2825,501 @@ out_unlock:
 	mutex_unlock(&c->tnc_mutex);
 	return ERR_PTR(err);
 }
+
+/**
+ * tnc_destroy_cnext - destroy left-over obsolete znodes from a failed commit.
+ * @c: UBIFS file-system description object
+ *
+ * Destroy left-over obsolete znodes from a failed commit.
+ */
+static void tnc_destroy_cnext(struct ubifs_info *c)
+{
+	struct ubifs_znode *cnext;
+
+	if (!c->cnext)
+		return;
+	ubifs_assert(c->cmt_state == COMMIT_BROKEN);
+	cnext = c->cnext;
+	do {
+		struct ubifs_znode *znode = cnext;
+
+		cnext = cnext->cnext;
+		if (ubifs_zn_obsolete(znode))
+			kfree(znode);
+	} while (cnext && cnext != c->cnext);
+}
+
+/**
+ * ubifs_tnc_close - close TNC subsystem and free all related resources.
+ * @c: UBIFS file-system description object
+ */
+void ubifs_tnc_close(struct ubifs_info *c)
+{
+	tnc_destroy_cnext(c);
+	if (c->zroot.znode) {
+		long n, freed;
+
+		n = atomic_long_read(&c->clean_zn_cnt);
+		freed = ubifs_destroy_tnc_subtree(c->zroot.znode);
+		ubifs_assert(freed == n);
+		atomic_long_sub(n, &ubifs_clean_zn_cnt);
+	}
+	kfree(c->gap_lebs);
+	kfree(c->ilebs);
+	destroy_old_idx(c);
+}
+
+/**
+ * left_znode - get the znode to the left.
+ * @c: UBIFS file-system description object
+ * @znode: znode
+ *
+ * This function returns a pointer to the znode to the left of @znode or NULL if
+ * there is not one. A negative error code is returned on failure.
+ */
+static struct ubifs_znode *left_znode(struct ubifs_info *c,
+				      struct ubifs_znode *znode)
+{
+	int level = znode->level;
+
+	while (1) {
+		int n = znode->iip - 1;
+
+		/* Go up until we can go left */
+		znode = znode->parent;
+		if (!znode)
+			return NULL;
+		if (n >= 0) {
+			/* Now go down the rightmost branch to 'level' */
+			znode = get_znode(c, znode, n);
+			if (IS_ERR(znode))
+				return znode;
+			while (znode->level != level) {
+				n = znode->child_cnt - 1;
+				znode = get_znode(c, znode, n);
+				if (IS_ERR(znode))
+					return znode;
+			}
+			break;
+		}
+	}
+	return znode;
+}
+
+/**
+ * right_znode - get the znode to the right.
+ * @c: UBIFS file-system description object
+ * @znode: znode
+ *
+ * This function returns a pointer to the znode to the right of @znode or NULL
+ * if there is not one. A negative error code is returned on failure.
+ */
+static struct ubifs_znode *right_znode(struct ubifs_info *c,
+				       struct ubifs_znode *znode)
+{
+	int level = znode->level;
+
+	while (1) {
+		int n = znode->iip + 1;
+
+		/* Go up until we can go right */
+		znode = znode->parent;
+		if (!znode)
+			return NULL;
+		if (n < znode->child_cnt) {
+			/* Now go down the leftmost branch to 'level' */
+			znode = get_znode(c, znode, n);
+			if (IS_ERR(znode))
+				return znode;
+			while (znode->level != level) {
+				znode = get_znode(c, znode, 0);
+				if (IS_ERR(znode))
+					return znode;
+			}
+			break;
+		}
+	}
+	return znode;
+}
+
+/**
+ * lookup_znode - find a particular indexing node from TNC.
+ * @c: UBIFS file-system description object
+ * @key: index node key to lookup
+ * @level: index node level
+ * @lnum: index node LEB number
+ * @offs: index node offset
+ *
+ * This function searches an indexing node by its first key @key and its
+ * address @lnum:@offs. It looks up the indexing tree by pulling all indexing
+ * nodes it traverses to TNC. This function is called for indexing nodes which
+ * were found on the media by scanning, for example when garbage-collecting or
+ * when doing in-the-gaps commit. This means that the indexing node which is
+ * looked for does not have to have exactly the same leftmost key @key, because
+ * the leftmost key may have been changed, in which case TNC will contain a
+ * dirty znode which still refers the same @lnum:@offs. This function is clever
+ * enough to recognize such indexing nodes.
+ *
+ * Note, if a znode was deleted or changed too much, then this function will
+ * not find it. For situations like this UBIFS has the old index RB-tree
+ * (indexed by @lnum:@offs).
+ *
+ * This function returns a pointer to the znode found or %NULL if it is not
+ * found. A negative error code is returned on failure.
+ */
+static struct ubifs_znode *lookup_znode(struct ubifs_info *c,
+					union ubifs_key *key, int level,
+					int lnum, int offs)
+{
+	struct ubifs_znode *znode, *zn;
+	int n, nn;
+
+	ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
+
+	/*
+	 * The arguments have probably been read off flash, so don't assume
+	 * they are valid.
+	 */
+	if (level < 0)
+		return ERR_PTR(-EINVAL);
+
+	/* Get the root znode */
+	znode = c->zroot.znode;
+	if (!znode) {
+		znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
+		if (IS_ERR(znode))
+			return znode;
+	}
+	/* Check if it is the one we are looking for */
+	if (c->zroot.lnum == lnum && c->zroot.offs == offs)
+		return znode;
+	/* Descend to the parent level i.e. (level + 1) */
+	if (level >= znode->level)
+		return NULL;
+	while (1) {
+		ubifs_search_zbranch(c, znode, key, &n);
+		if (n < 0) {
+			/*
+			 * We reached a znode where the leftmost key is greater
+			 * than the key we are searching for. This is the same
+			 * situation as the one described in a huge comment at
+			 * the end of the 'ubifs_lookup_level0()' function. And
+			 * for exactly the same reasons we have to try to look
+			 * left before giving up.
+			 */
+			znode = left_znode(c, znode);
+			if (!znode)
+				return NULL;
+			if (IS_ERR(znode))
+				return znode;
+			ubifs_search_zbranch(c, znode, key, &n);
+			ubifs_assert(n >= 0);
+		}
+		if (znode->level == level + 1)
+			break;
+		znode = get_znode(c, znode, n);
+		if (IS_ERR(znode))
+			return znode;
+	}
+	/* Check if the child is the one we are looking for */
+	if (znode->zbranch[n].lnum == lnum && znode->zbranch[n].offs == offs)
+		return get_znode(c, znode, n);
+	/* If the key is unique, there is nowhere else to look */
+	if (!is_hash_key(c, key))
+		return NULL;
+	/*
+	 * The key is not unique and so may be also in the znodes to either
+	 * side.
+	 */
+	zn = znode;
+	nn = n;
+	/* Look left */
+	while (1) {
+		/* Move one branch to the left */
+		if (n)
+			n -= 1;
+		else {
+			znode = left_znode(c, znode);
+			if (!znode)
+				break;
+			if (IS_ERR(znode))
+				return znode;
+			n = znode->child_cnt - 1;
+		}
+		/* Check it */
+		if (znode->zbranch[n].lnum == lnum &&
+		    znode->zbranch[n].offs == offs)
+			return get_znode(c, znode, n);
+		/* Stop if the key is less than the one we are looking for */
+		if (keys_cmp(c, &znode->zbranch[n].key, key) < 0)
+			break;
+	}
+	/* Back to the middle */
+	znode = zn;
+	n = nn;
+	/* Look right */
+	while (1) {
+		/* Move one branch to the right */
+		if (++n >= znode->child_cnt) {
+			znode = right_znode(c, znode);
+			if (!znode)
+				break;
+			if (IS_ERR(znode))
+				return znode;
+			n = 0;
+		}
+		/* Check it */
+		if (znode->zbranch[n].lnum == lnum &&
+		    znode->zbranch[n].offs == offs)
+			return get_znode(c, znode, n);
+		/* Stop if the key is greater than the one we are looking for */
+		if (keys_cmp(c, &znode->zbranch[n].key, key) > 0)
+			break;
+	}
+	return NULL;
+}
+
+/**
+ * is_idx_node_in_tnc - determine if an index node is in the TNC.
+ * @c: UBIFS file-system description object
+ * @key: key of index node
+ * @level: index node level
+ * @lnum: LEB number of index node
+ * @offs: offset of index node
+ *
+ * This function returns %0 if the index node is not referred to in the TNC, %1
+ * if the index node is referred to in the TNC and the corresponding znode is
+ * dirty, %2 if an index node is referred to in the TNC and the corresponding
+ * znode is clean, and a negative error code in case of failure.
+ *
+ * Note, the @key argument has to be the key of the first child. Also note,
+ * this function relies on the fact that 0:0 is never a valid LEB number and
+ * offset for a main-area node.
+ */
+int is_idx_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, int level,
+		       int lnum, int offs)
+{
+	struct ubifs_znode *znode;
+
+	znode = lookup_znode(c, key, level, lnum, offs);
+	if (!znode)
+		return 0;
+	if (IS_ERR(znode))
+		return PTR_ERR(znode);
+
+	return ubifs_zn_dirty(znode) ? 1 : 2;
+}
+
+/**
+ * is_leaf_node_in_tnc - determine if a non-indexing not is in the TNC.
+ * @c: UBIFS file-system description object
+ * @key: node key
+ * @lnum: node LEB number
+ * @offs: node offset
+ *
+ * This function returns %1 if the node is referred to in the TNC, %0 if it is
+ * not, and a negative error code in case of failure.
+ *
+ * Note, this function relies on the fact that 0:0 is never a valid LEB number
+ * and offset for a main-area node.
+ */
+static int is_leaf_node_in_tnc(struct ubifs_info *c, union ubifs_key *key,
+			       int lnum, int offs)
+{
+	struct ubifs_zbranch *zbr;
+	struct ubifs_znode *znode, *zn;
+	int n, found, err, nn;
+	const int unique = !is_hash_key(c, key);
+
+	found = ubifs_lookup_level0(c, key, &znode, &n);
+	if (found < 0)
+		return found; /* Error code */
+	if (!found)
+		return 0;
+	zbr = &znode->zbranch[n];
+	if (lnum == zbr->lnum && offs == zbr->offs)
+		return 1; /* Found it */
+	if (unique)
+		return 0;
+	/*
+	 * Because the key is not unique, we have to look left
+	 * and right as well
+	 */
+	zn = znode;
+	nn = n;
+	/* Look left */
+	while (1) {
+		err = tnc_prev(c, &znode, &n);
+		if (err == -ENOENT)
+			break;
+		if (err)
+			return err;
+		if (keys_cmp(c, key, &znode->zbranch[n].key))
+			break;
+		zbr = &znode->zbranch[n];
+		if (lnum == zbr->lnum && offs == zbr->offs)
+			return 1; /* Found it */
+	}
+	/* Look right */
+	znode = zn;
+	n = nn;
+	while (1) {
+		err = tnc_next(c, &znode, &n);
+		if (err) {
+			if (err == -ENOENT)
+				return 0;
+			return err;
+		}
+		if (keys_cmp(c, key, &znode->zbranch[n].key))
+			break;
+		zbr = &znode->zbranch[n];
+		if (lnum == zbr->lnum && offs == zbr->offs)
+			return 1; /* Found it */
+	}
+	return 0;
+}
+
+/**
+ * ubifs_tnc_has_node - determine whether a node is in the TNC.
+ * @c: UBIFS file-system description object
+ * @key: node key
+ * @level: index node level (if it is an index node)
+ * @lnum: node LEB number
+ * @offs: node offset
+ * @is_idx: non-zero if the node is an index node
+ *
+ * This function returns %1 if the node is in the TNC, %0 if it is not, and a
+ * negative error code in case of failure. For index nodes, @key has to be the
+ * key of the first child. An index node is considered to be in the TNC only if
+ * the corresponding znode is clean or has not been loaded.
+ */
+int ubifs_tnc_has_node(struct ubifs_info *c, union ubifs_key *key, int level,
+		       int lnum, int offs, int is_idx)
+{
+	int err;
+
+	mutex_lock(&c->tnc_mutex);
+	if (is_idx) {
+		err = is_idx_node_in_tnc(c, key, level, lnum, offs);
+		if (err < 0)
+			goto out_unlock;
+		if (err == 1)
+			/* The index node was found but it was dirty */
+			err = 0;
+		else if (err == 2)
+			/* The index node was found and it was clean */
+			err = 1;
+		else
+			BUG_ON(err != 0);
+	} else
+		err = is_leaf_node_in_tnc(c, key, lnum, offs);
+
+out_unlock:
+	mutex_unlock(&c->tnc_mutex);
+	return err;
+}
+
+/**
+ * ubifs_dirty_idx_node - dirty an index node.
+ * @c: UBIFS file-system description object
+ * @key: index node key
+ * @level: index node level
+ * @lnum: index node LEB number
+ * @offs: index node offset
+ *
+ * This function loads and dirties an index node so that it can be garbage
+ * collected. The @key argument has to be the key of the first child. This
+ * function relies on the fact that 0:0 is never a valid LEB number and offset
+ * for a main-area node. Returns %0 on success and a negative error code on
+ * failure.
+ */
+int ubifs_dirty_idx_node(struct ubifs_info *c, union ubifs_key *key, int level,
+			 int lnum, int offs)
+{
+	struct ubifs_znode *znode;
+	int err = 0;
+
+	mutex_lock(&c->tnc_mutex);
+	znode = lookup_znode(c, key, level, lnum, offs);
+	if (!znode)
+		goto out_unlock;
+	if (IS_ERR(znode)) {
+		err = PTR_ERR(znode);
+		goto out_unlock;
+	}
+	znode = dirty_cow_bottom_up(c, znode);
+	if (IS_ERR(znode)) {
+		err = PTR_ERR(znode);
+		goto out_unlock;
+	}
+
+out_unlock:
+	mutex_unlock(&c->tnc_mutex);
+	return err;
+}
+
+/**
+ * dbg_check_inode_size - check if inode size is correct.
+ * @c: UBIFS file-system description object
+ * @inum: inode number
+ * @size: inode size
+ *
+ * This function makes sure that the inode size (@size) is correct and it does
+ * not have any pages beyond @size. Returns zero if the inode is OK, %-EINVAL
+ * if it has a data page beyond @size, and other negative error code in case of
+ * other errors.
+ */
+int dbg_check_inode_size(struct ubifs_info *c, const struct inode *inode,
+			 loff_t size)
+{
+	int err, n;
+	union ubifs_key from_key, to_key, *key;
+	struct ubifs_znode *znode;
+	unsigned int block;
+
+	if (!S_ISREG(inode->i_mode))
+		return 0;
+	if (!dbg_is_chk_gen(c))
+		return 0;
+
+	block = (size + UBIFS_BLOCK_SIZE - 1) >> UBIFS_BLOCK_SHIFT;
+	data_key_init(c, &from_key, inode->i_ino, block);
+	highest_data_key(c, &to_key, inode->i_ino);
+
+	mutex_lock(&c->tnc_mutex);
+	err = ubifs_lookup_level0(c, &from_key, &znode, &n);
+	if (err < 0)
+		goto out_unlock;
+
+	if (err) {
+		key = &from_key;
+		goto out_dump;
+	}
+
+	err = tnc_next(c, &znode, &n);
+	if (err == -ENOENT) {
+		err = 0;
+		goto out_unlock;
+	}
+	if (err < 0)
+		goto out_unlock;
+
+	ubifs_assert(err == 0);
+	key = &znode->zbranch[n].key;
+	if (!key_in_range(c, key, &from_key, &to_key))
+		goto out_unlock;
+
+out_dump:
+	block = key_block(c, key);
+	ubifs_err(c, "inode %lu has size %lld, but there are data at offset %lld",
+		  (unsigned long)inode->i_ino, size,
+		  ((loff_t)block) << UBIFS_BLOCK_SHIFT);
+	mutex_unlock(&c->tnc_mutex);
+	ubifs_dump_inode(c, inode);
+	dump_stack();
+	return -EINVAL;
+
+out_unlock:
+	mutex_unlock(&c->tnc_mutex);
+	return err;
+}