Initial import

1 files changed, 1466 insertions, 0 deletions

diff --git a/fs/ubifs/journal.c b/fs/ubifs/journal.c
new file mode 100644
index 000000000..0b9da5b6e
--- /dev/null
+++ b/fs/ubifs/journal.c
@@ -0,0 +1,1466 @@
+/*
+ * This file is part of UBIFS.
+ *
+ * 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
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём)
+ *          Adrian Hunter
+ */
+
+/*
+ * This file implements UBIFS journal.
+ *
+ * The journal consists of 2 parts - the log and bud LEBs. The log has fixed
+ * length and position, while a bud logical eraseblock is any LEB in the main
+ * area. Buds contain file system data - data nodes, inode nodes, etc. The log
+ * contains only references to buds and some other stuff like commit
+ * start node. The idea is that when we commit the journal, we do
+ * not copy the data, the buds just become indexed. Since after the commit the
+ * nodes in bud eraseblocks become leaf nodes of the file system index tree, we
+ * use term "bud". Analogy is obvious, bud eraseblocks contain nodes which will
+ * become leafs in the future.
+ *
+ * The journal is multi-headed because we want to write data to the journal as
+ * optimally as possible. It is nice to have nodes belonging to the same inode
+ * in one LEB, so we may write data owned by different inodes to different
+ * journal heads, although at present only one data head is used.
+ *
+ * For recovery reasons, the base head contains all inode nodes, all directory
+ * entry nodes and all truncate nodes. This means that the other heads contain
+ * only data nodes.
+ *
+ * Bud LEBs may be half-indexed. For example, if the bud was not full at the
+ * time of commit, the bud is retained to continue to be used in the journal,
+ * even though the "front" of the LEB is now indexed. In that case, the log
+ * reference contains the offset where the bud starts for the purposes of the
+ * journal.
+ *
+ * The journal size has to be limited, because the larger is the journal, the
+ * longer it takes to mount UBIFS (scanning the journal) and the more memory it
+ * takes (indexing in the TNC).
+ *
+ * All the journal write operations like 'ubifs_jnl_update()' here, which write
+ * multiple UBIFS nodes to the journal at one go, are atomic with respect to
+ * unclean reboots. Should the unclean reboot happen, the recovery code drops
+ * all the nodes.
+ */
+
+#include "ubifs.h"
+
+/**
+ * zero_ino_node_unused - zero out unused fields of an on-flash inode node.
+ * @ino: the inode to zero out
+ */
+static inline void zero_ino_node_unused(struct ubifs_ino_node *ino)
+{
+	memset(ino->padding1, 0, 4);
+	memset(ino->padding2, 0, 26);
+}
+
+/**
+ * zero_dent_node_unused - zero out unused fields of an on-flash directory
+ *                         entry node.
+ * @dent: the directory entry to zero out
+ */
+static inline void zero_dent_node_unused(struct ubifs_dent_node *dent)
+{
+	dent->padding1 = 0;
+	memset(dent->padding2, 0, 4);
+}
+
+/**
+ * zero_data_node_unused - zero out unused fields of an on-flash data node.
+ * @data: the data node to zero out
+ */
+static inline void zero_data_node_unused(struct ubifs_data_node *data)
+{
+	memset(data->padding, 0, 2);
+}
+
+/**
+ * zero_trun_node_unused - zero out unused fields of an on-flash truncation
+ *                         node.
+ * @trun: the truncation node to zero out
+ */
+static inline void zero_trun_node_unused(struct ubifs_trun_node *trun)
+{
+	memset(trun->padding, 0, 12);
+}
+
+/**
+ * reserve_space - reserve space in the journal.
+ * @c: UBIFS file-system description object
+ * @jhead: journal head number
+ * @len: node length
+ *
+ * This function reserves space in journal head @head. If the reservation
+ * succeeded, the journal head stays locked and later has to be unlocked using
+ * 'release_head()'. 'write_node()' and 'write_head()' functions also unlock
+ * it. Returns zero in case of success, %-EAGAIN if commit has to be done, and
+ * other negative error codes in case of other failures.
+ */
+static int reserve_space(struct ubifs_info *c, int jhead, int len)
+{
+	int err = 0, err1, retries = 0, avail, lnum, offs, squeeze;
+	struct ubifs_wbuf *wbuf = &c->jheads[jhead].wbuf;
+
+	/*
+	 * Typically, the base head has smaller nodes written to it, so it is
+	 * better to try to allocate space at the ends of eraseblocks. This is
+	 * what the squeeze parameter does.
+	 */
+	ubifs_assert(!c->ro_media && !c->ro_mount);
+	squeeze = (jhead == BASEHD);
+again:
+	mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
+
+	if (c->ro_error) {
+		err = -EROFS;
+		goto out_unlock;
+	}
+
+	avail = c->leb_size - wbuf->offs - wbuf->used;
+	if (wbuf->lnum != -1 && avail >= len)
+		return 0;
+
+	/*
+	 * Write buffer wasn't seek'ed or there is no enough space - look for an
+	 * LEB with some empty space.
+	 */
+	lnum = ubifs_find_free_space(c, len, &offs, squeeze);
+	if (lnum >= 0)
+		goto out;
+
+	err = lnum;
+	if (err != -ENOSPC)
+		goto out_unlock;
+
+	/*
+	 * No free space, we have to run garbage collector to make
+	 * some. But the write-buffer mutex has to be unlocked because
+	 * GC also takes it.
+	 */
+	dbg_jnl("no free space in jhead %s, run GC", dbg_jhead(jhead));
+	mutex_unlock(&wbuf->io_mutex);
+
+	lnum = ubifs_garbage_collect(c, 0);
+	if (lnum < 0) {
+		err = lnum;
+		if (err != -ENOSPC)
+			return err;
+
+		/*
+		 * GC could not make a free LEB. But someone else may
+		 * have allocated new bud for this journal head,
+		 * because we dropped @wbuf->io_mutex, so try once
+		 * again.
+		 */
+		dbg_jnl("GC couldn't make a free LEB for jhead %s",
+			dbg_jhead(jhead));
+		if (retries++ < 2) {
+			dbg_jnl("retry (%d)", retries);
+			goto again;
+		}
+
+		dbg_jnl("return -ENOSPC");
+		return err;
+	}
+
+	mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
+	dbg_jnl("got LEB %d for jhead %s", lnum, dbg_jhead(jhead));
+	avail = c->leb_size - wbuf->offs - wbuf->used;
+
+	if (wbuf->lnum != -1 && avail >= len) {
+		/*
+		 * Someone else has switched the journal head and we have
+		 * enough space now. This happens when more than one process is
+		 * trying to write to the same journal head at the same time.
+		 */
+		dbg_jnl("return LEB %d back, already have LEB %d:%d",
+			lnum, wbuf->lnum, wbuf->offs + wbuf->used);
+		err = ubifs_return_leb(c, lnum);
+		if (err)
+			goto out_unlock;
+		return 0;
+	}
+
+	offs = 0;
+
+out:
+	/*
+	 * Make sure we synchronize the write-buffer before we add the new bud
+	 * to the log. Otherwise we may have a power cut after the log
+	 * reference node for the last bud (@lnum) is written but before the
+	 * write-buffer data are written to the next-to-last bud
+	 * (@wbuf->lnum). And the effect would be that the recovery would see
+	 * that there is corruption in the next-to-last bud.
+	 */
+	err = ubifs_wbuf_sync_nolock(wbuf);
+	if (err)
+		goto out_return;
+	err = ubifs_add_bud_to_log(c, jhead, lnum, offs);
+	if (err)
+		goto out_return;
+	err = ubifs_wbuf_seek_nolock(wbuf, lnum, offs);
+	if (err)
+		goto out_unlock;
+
+	return 0;
+
+out_unlock:
+	mutex_unlock(&wbuf->io_mutex);
+	return err;
+
+out_return:
+	/* An error occurred and the LEB has to be returned to lprops */
+	ubifs_assert(err < 0);
+	err1 = ubifs_return_leb(c, lnum);
+	if (err1 && err == -EAGAIN)
+		/*
+		 * Return original error code only if it is not %-EAGAIN,
+		 * which is not really an error. Otherwise, return the error
+		 * code of 'ubifs_return_leb()'.
+		 */
+		err = err1;
+	mutex_unlock(&wbuf->io_mutex);
+	return err;
+}
+
+/**
+ * write_node - write node to a journal head.
+ * @c: UBIFS file-system description object
+ * @jhead: journal head
+ * @node: node to write
+ * @len: node length
+ * @lnum: LEB number written is returned here
+ * @offs: offset written is returned here
+ *
+ * This function writes a node to reserved space of journal head @jhead.
+ * Returns zero in case of success and a negative error code in case of
+ * failure.
+ */
+static int write_node(struct ubifs_info *c, int jhead, void *node, int len,
+		      int *lnum, int *offs)
+{
+	struct ubifs_wbuf *wbuf = &c->jheads[jhead].wbuf;
+
+	ubifs_assert(jhead != GCHD);
+
+	*lnum = c->jheads[jhead].wbuf.lnum;
+	*offs = c->jheads[jhead].wbuf.offs + c->jheads[jhead].wbuf.used;
+
+	dbg_jnl("jhead %s, LEB %d:%d, len %d",
+		dbg_jhead(jhead), *lnum, *offs, len);
+	ubifs_prepare_node(c, node, len, 0);
+
+	return ubifs_wbuf_write_nolock(wbuf, node, len);
+}
+
+/**
+ * write_head - write data to a journal head.
+ * @c: UBIFS file-system description object
+ * @jhead: journal head
+ * @buf: buffer to write
+ * @len: length to write
+ * @lnum: LEB number written is returned here
+ * @offs: offset written is returned here
+ * @sync: non-zero if the write-buffer has to by synchronized
+ *
+ * This function is the same as 'write_node()' but it does not assume the
+ * buffer it is writing is a node, so it does not prepare it (which means
+ * initializing common header and calculating CRC).
+ */
+static int write_head(struct ubifs_info *c, int jhead, void *buf, int len,
+		      int *lnum, int *offs, int sync)
+{
+	int err;
+	struct ubifs_wbuf *wbuf = &c->jheads[jhead].wbuf;
+
+	ubifs_assert(jhead != GCHD);
+
+	*lnum = c->jheads[jhead].wbuf.lnum;
+	*offs = c->jheads[jhead].wbuf.offs + c->jheads[jhead].wbuf.used;
+	dbg_jnl("jhead %s, LEB %d:%d, len %d",
+		dbg_jhead(jhead), *lnum, *offs, len);
+
+	err = ubifs_wbuf_write_nolock(wbuf, buf, len);
+	if (err)
+		return err;
+	if (sync)
+		err = ubifs_wbuf_sync_nolock(wbuf);
+	return err;
+}
+
+/**
+ * make_reservation - reserve journal space.
+ * @c: UBIFS file-system description object
+ * @jhead: journal head
+ * @len: how many bytes to reserve
+ *
+ * This function makes space reservation in journal head @jhead. The function
+ * takes the commit lock and locks the journal head, and the caller has to
+ * unlock the head and finish the reservation with 'finish_reservation()'.
+ * Returns zero in case of success and a negative error code in case of
+ * failure.
+ *
+ * Note, the journal head may be unlocked as soon as the data is written, while
+ * the commit lock has to be released after the data has been added to the
+ * TNC.
+ */
+static int make_reservation(struct ubifs_info *c, int jhead, int len)
+{
+	int err, cmt_retries = 0, nospc_retries = 0;
+
+again:
+	down_read(&c->commit_sem);
+	err = reserve_space(c, jhead, len);
+	if (!err)
+		return 0;
+	up_read(&c->commit_sem);
+
+	if (err == -ENOSPC) {
+		/*
+		 * GC could not make any progress. We should try to commit
+		 * once because it could make some dirty space and GC would
+		 * make progress, so make the error -EAGAIN so that the below
+		 * will commit and re-try.
+		 */
+		if (nospc_retries++ < 2) {
+			dbg_jnl("no space, retry");
+			err = -EAGAIN;
+		}
+
+		/*
+		 * This means that the budgeting is incorrect. We always have
+		 * to be able to write to the media, because all operations are
+		 * budgeted. Deletions are not budgeted, though, but we reserve
+		 * an extra LEB for them.
+		 */
+	}
+
+	if (err != -EAGAIN)
+		goto out;
+
+	/*
+	 * -EAGAIN means that the journal is full or too large, or the above
+	 * code wants to do one commit. Do this and re-try.
+	 */
+	if (cmt_retries > 128) {
+		/*
+		 * This should not happen unless the journal size limitations
+		 * are too tough.
+		 */
+		ubifs_err(c, "stuck in space allocation");
+		err = -ENOSPC;
+		goto out;
+	} else if (cmt_retries > 32)
+		ubifs_warn(c, "too many space allocation re-tries (%d)",
+			   cmt_retries);
+
+	dbg_jnl("-EAGAIN, commit and retry (retried %d times)",
+		cmt_retries);
+	cmt_retries += 1;
+
+	err = ubifs_run_commit(c);
+	if (err)
+		return err;
+	goto again;
+
+out:
+	ubifs_err(c, "cannot reserve %d bytes in jhead %d, error %d",
+		  len, jhead, err);
+	if (err == -ENOSPC) {
+		/* This are some budgeting problems, print useful information */
+		down_write(&c->commit_sem);
+		dump_stack();
+		ubifs_dump_budg(c, &c->bi);
+		ubifs_dump_lprops(c);
+		cmt_retries = dbg_check_lprops(c);
+		up_write(&c->commit_sem);
+	}
+	return err;
+}
+
+/**
+ * release_head - release a journal head.
+ * @c: UBIFS file-system description object
+ * @jhead: journal head
+ *
+ * This function releases journal head @jhead which was locked by
+ * the 'make_reservation()' function. It has to be called after each successful
+ * 'make_reservation()' invocation.
+ */
+static inline void release_head(struct ubifs_info *c, int jhead)
+{
+	mutex_unlock(&c->jheads[jhead].wbuf.io_mutex);
+}
+
+/**
+ * finish_reservation - finish a reservation.
+ * @c: UBIFS file-system description object
+ *
+ * This function finishes journal space reservation. It must be called after
+ * 'make_reservation()'.
+ */
+static void finish_reservation(struct ubifs_info *c)
+{
+	up_read(&c->commit_sem);
+}
+
+/**
+ * get_dent_type - translate VFS inode mode to UBIFS directory entry type.
+ * @mode: inode mode
+ */
+static int get_dent_type(int mode)
+{
+	switch (mode & S_IFMT) {
+	case S_IFREG:
+		return UBIFS_ITYPE_REG;
+	case S_IFDIR:
+		return UBIFS_ITYPE_DIR;
+	case S_IFLNK:
+		return UBIFS_ITYPE_LNK;
+	case S_IFBLK:
+		return UBIFS_ITYPE_BLK;
+	case S_IFCHR:
+		return UBIFS_ITYPE_CHR;
+	case S_IFIFO:
+		return UBIFS_ITYPE_FIFO;
+	case S_IFSOCK:
+		return UBIFS_ITYPE_SOCK;
+	default:
+		BUG();
+	}
+	return 0;
+}
+
+/**
+ * pack_inode - pack an inode node.
+ * @c: UBIFS file-system description object
+ * @ino: buffer in which to pack inode node
+ * @inode: inode to pack
+ * @last: indicates the last node of the group
+ */
+static void pack_inode(struct ubifs_info *c, struct ubifs_ino_node *ino,
+		       const struct inode *inode, int last)
+{
+	int data_len = 0, last_reference = !inode->i_nlink;
+	struct ubifs_inode *ui = ubifs_inode(inode);
+
+	ino->ch.node_type = UBIFS_INO_NODE;
+	ino_key_init_flash(c, &ino->key, inode->i_ino);
+	ino->creat_sqnum = cpu_to_le64(ui->creat_sqnum);
+	ino->atime_sec  = cpu_to_le64(inode->i_atime.tv_sec);
+	ino->atime_nsec = cpu_to_le32(inode->i_atime.tv_nsec);
+	ino->ctime_sec  = cpu_to_le64(inode->i_ctime.tv_sec);
+	ino->ctime_nsec = cpu_to_le32(inode->i_ctime.tv_nsec);
+	ino->mtime_sec  = cpu_to_le64(inode->i_mtime.tv_sec);
+	ino->mtime_nsec = cpu_to_le32(inode->i_mtime.tv_nsec);
+	ino->uid   = cpu_to_le32(i_uid_read(inode));
+	ino->gid   = cpu_to_le32(i_gid_read(inode));
+	ino->mode  = cpu_to_le32(inode->i_mode);
+	ino->flags = cpu_to_le32(ui->flags);
+	ino->size  = cpu_to_le64(ui->ui_size);
+	ino->nlink = cpu_to_le32(inode->i_nlink);
+	ino->compr_type  = cpu_to_le16(ui->compr_type);
+	ino->data_len    = cpu_to_le32(ui->data_len);
+	ino->xattr_cnt   = cpu_to_le32(ui->xattr_cnt);
+	ino->xattr_size  = cpu_to_le32(ui->xattr_size);
+	ino->xattr_names = cpu_to_le32(ui->xattr_names);
+	zero_ino_node_unused(ino);
+
+	/*
+	 * Drop the attached data if this is a deletion inode, the data is not
+	 * needed anymore.
+	 */
+	if (!last_reference) {
+		memcpy(ino->data, ui->data, ui->data_len);
+		data_len = ui->data_len;
+	}
+
+	ubifs_prep_grp_node(c, ino, UBIFS_INO_NODE_SZ + data_len, last);
+}
+
+/**
+ * mark_inode_clean - mark UBIFS inode as clean.
+ * @c: UBIFS file-system description object
+ * @ui: UBIFS inode to mark as clean
+ *
+ * This helper function marks UBIFS inode @ui as clean by cleaning the
+ * @ui->dirty flag and releasing its budget. Note, VFS may still treat the
+ * inode as dirty and try to write it back, but 'ubifs_write_inode()' would
+ * just do nothing.
+ */
+static void mark_inode_clean(struct ubifs_info *c, struct ubifs_inode *ui)
+{
+	if (ui->dirty)
+		ubifs_release_dirty_inode_budget(c, ui);
+	ui->dirty = 0;
+}
+
+/**
+ * ubifs_jnl_update - update inode.
+ * @c: UBIFS file-system description object
+ * @dir: parent inode or host inode in case of extended attributes
+ * @nm: directory entry name
+ * @inode: inode to update
+ * @deletion: indicates a directory entry deletion i.e unlink or rmdir
+ * @xent: non-zero if the directory entry is an extended attribute entry
+ *
+ * This function updates an inode by writing a directory entry (or extended
+ * attribute entry), the inode itself, and the parent directory inode (or the
+ * host inode) to the journal.
+ *
+ * The function writes the host inode @dir last, which is important in case of
+ * extended attributes. Indeed, then we guarantee that if the host inode gets
+ * synchronized (with 'fsync()'), and the write-buffer it sits in gets flushed,
+ * the extended attribute inode gets flushed too. And this is exactly what the
+ * user expects - synchronizing the host inode synchronizes its extended
+ * attributes. Similarly, this guarantees that if @dir is synchronized, its
+ * directory entry corresponding to @nm gets synchronized too.
+ *
+ * If the inode (@inode) or the parent directory (@dir) are synchronous, this
+ * function synchronizes the write-buffer.
+ *
+ * This function marks the @dir and @inode inodes as clean and returns zero on
+ * success. In case of failure, a negative error code is returned.
+ */
+int ubifs_jnl_update(struct ubifs_info *c, const struct inode *dir,
+		     const struct qstr *nm, const struct inode *inode,
+		     int deletion, int xent)
+{
+	int err, dlen, ilen, len, lnum, ino_offs, dent_offs;
+	int aligned_dlen, aligned_ilen, sync = IS_DIRSYNC(dir);
+	int last_reference = !!(deletion && inode->i_nlink == 0);
+	struct ubifs_inode *ui = ubifs_inode(inode);
+	struct ubifs_inode *host_ui = ubifs_inode(dir);
+	struct ubifs_dent_node *dent;
+	struct ubifs_ino_node *ino;
+	union ubifs_key dent_key, ino_key;
+
+	dbg_jnl("ino %lu, dent '%.*s', data len %d in dir ino %lu",
+		inode->i_ino, nm->len, nm->name, ui->data_len, dir->i_ino);
+	ubifs_assert(mutex_is_locked(&host_ui->ui_mutex));
+
+	dlen = UBIFS_DENT_NODE_SZ + nm->len + 1;
+	ilen = UBIFS_INO_NODE_SZ;
+
+	/*
+	 * If the last reference to the inode is being deleted, then there is
+	 * no need to attach and write inode data, it is being deleted anyway.
+	 * And if the inode is being deleted, no need to synchronize
+	 * write-buffer even if the inode is synchronous.
+	 */
+	if (!last_reference) {
+		ilen += ui->data_len;
+		sync |= IS_SYNC(inode);
+	}
+
+	aligned_dlen = ALIGN(dlen, 8);
+	aligned_ilen = ALIGN(ilen, 8);
+
+	len = aligned_dlen + aligned_ilen + UBIFS_INO_NODE_SZ;
+	/* Make sure to also account for extended attributes */
+	len += host_ui->data_len;
+
+	dent = kmalloc(len, GFP_NOFS);
+	if (!dent)
+		return -ENOMEM;
+
+	/* Make reservation before allocating sequence numbers */
+	err = make_reservation(c, BASEHD, len);
+	if (err)
+		goto out_free;
+
+	if (!xent) {
+		dent->ch.node_type = UBIFS_DENT_NODE;
+		dent_key_init(c, &dent_key, dir->i_ino, nm);
+	} else {
+		dent->ch.node_type = UBIFS_XENT_NODE;
+		xent_key_init(c, &dent_key, dir->i_ino, nm);
+	}
+
+	key_write(c, &dent_key, dent->key);
+	dent->inum = deletion ? 0 : cpu_to_le64(inode->i_ino);
+	dent->type = get_dent_type(inode->i_mode);
+	dent->nlen = cpu_to_le16(nm->len);
+	memcpy(dent->name, nm->name, nm->len);
+	dent->name[nm->len] = '\0';
+	zero_dent_node_unused(dent);
+	ubifs_prep_grp_node(c, dent, dlen, 0);
+
+	ino = (void *)dent + aligned_dlen;
+	pack_inode(c, ino, inode, 0);
+	ino = (void *)ino + aligned_ilen;
+	pack_inode(c, ino, dir, 1);
+
+	if (last_reference) {
+		err = ubifs_add_orphan(c, inode->i_ino);
+		if (err) {
+			release_head(c, BASEHD);
+			goto out_finish;
+		}
+		ui->del_cmtno = c->cmt_no;
+	}
+
+	err = write_head(c, BASEHD, dent, len, &lnum, &dent_offs, sync);
+	if (err)
+		goto out_release;
+	if (!sync) {
+		struct ubifs_wbuf *wbuf = &c->jheads[BASEHD].wbuf;
+
+		ubifs_wbuf_add_ino_nolock(wbuf, inode->i_ino);
+		ubifs_wbuf_add_ino_nolock(wbuf, dir->i_ino);
+	}
+	release_head(c, BASEHD);
+	kfree(dent);
+
+	if (deletion) {
+		err = ubifs_tnc_remove_nm(c, &dent_key, nm);
+		if (err)
+			goto out_ro;
+		err = ubifs_add_dirt(c, lnum, dlen);
+	} else
+		err = ubifs_tnc_add_nm(c, &dent_key, lnum, dent_offs, dlen, nm);
+	if (err)
+		goto out_ro;
+
+	/*
+	 * Note, we do not remove the inode from TNC even if the last reference
+	 * to it has just been deleted, because the inode may still be opened.
+	 * Instead, the inode has been added to orphan lists and the orphan
+	 * subsystem will take further care about it.
+	 */
+	ino_key_init(c, &ino_key, inode->i_ino);
+	ino_offs = dent_offs + aligned_dlen;
+	err = ubifs_tnc_add(c, &ino_key, lnum, ino_offs, ilen);
+	if (err)
+		goto out_ro;
+
+	ino_key_init(c, &ino_key, dir->i_ino);
+	ino_offs += aligned_ilen;
+	err = ubifs_tnc_add(c, &ino_key, lnum, ino_offs,
+			    UBIFS_INO_NODE_SZ + host_ui->data_len);
+	if (err)
+		goto out_ro;
+
+	finish_reservation(c);
+	spin_lock(&ui->ui_lock);
+	ui->synced_i_size = ui->ui_size;
+	spin_unlock(&ui->ui_lock);
+	mark_inode_clean(c, ui);
+	mark_inode_clean(c, host_ui);
+	return 0;
+
+out_finish:
+	finish_reservation(c);
+out_free:
+	kfree(dent);
+	return err;
+
+out_release:
+	release_head(c, BASEHD);
+	kfree(dent);
+out_ro:
+	ubifs_ro_mode(c, err);
+	if (last_reference)
+		ubifs_delete_orphan(c, inode->i_ino);
+	finish_reservation(c);
+	return err;
+}
+
+/**
+ * ubifs_jnl_write_data - write a data node to the journal.
+ * @c: UBIFS file-system description object
+ * @inode: inode the data node belongs to
+ * @key: node key
+ * @buf: buffer to write
+ * @len: data length (must not exceed %UBIFS_BLOCK_SIZE)
+ *
+ * This function writes a data node to the journal. Returns %0 if the data node
+ * was successfully written, and a negative error code in case of failure.
+ */
+int ubifs_jnl_write_data(struct ubifs_info *c, const struct inode *inode,
+			 const union ubifs_key *key, const void *buf, int len)
+{
+	struct ubifs_data_node *data;
+	int err, lnum, offs, compr_type, out_len;
+	int dlen = COMPRESSED_DATA_NODE_BUF_SZ, allocated = 1;
+	struct ubifs_inode *ui = ubifs_inode(inode);
+
+	dbg_jnlk(key, "ino %lu, blk %u, len %d, key ",
+		(unsigned long)key_inum(c, key), key_block(c, key), len);
+	ubifs_assert(len <= UBIFS_BLOCK_SIZE);
+
+	data = kmalloc(dlen, GFP_NOFS | __GFP_NOWARN);
+	if (!data) {
+		/*
+		 * Fall-back to the write reserve buffer. Note, we might be
+		 * currently on the memory reclaim path, when the kernel is
+		 * trying to free some memory by writing out dirty pages. The
+		 * write reserve buffer helps us to guarantee that we are
+		 * always able to write the data.
+		 */
+		allocated = 0;
+		mutex_lock(&c->write_reserve_mutex);
+		data = c->write_reserve_buf;
+	}
+
+	data->ch.node_type = UBIFS_DATA_NODE;
+	key_write(c, key, &data->key);
+	data->size = cpu_to_le32(len);
+	zero_data_node_unused(data);
+
+	if (!(ui->flags & UBIFS_COMPR_FL))
+		/* Compression is disabled for this inode */
+		compr_type = UBIFS_COMPR_NONE;
+	else
+		compr_type = ui->compr_type;
+
+	out_len = dlen - UBIFS_DATA_NODE_SZ;
+	ubifs_compress(c, buf, len, &data->data, &out_len, &compr_type);
+	ubifs_assert(out_len <= UBIFS_BLOCK_SIZE);
+
+	dlen = UBIFS_DATA_NODE_SZ + out_len;
+	data->compr_type = cpu_to_le16(compr_type);
+
+	/* Make reservation before allocating sequence numbers */
+	err = make_reservation(c, DATAHD, dlen);
+	if (err)
+		goto out_free;
+
+	err = write_node(c, DATAHD, data, dlen, &lnum, &offs);
+	if (err)
+		goto out_release;
+	ubifs_wbuf_add_ino_nolock(&c->jheads[DATAHD].wbuf, key_inum(c, key));
+	release_head(c, DATAHD);
+
+	err = ubifs_tnc_add(c, key, lnum, offs, dlen);
+	if (err)
+		goto out_ro;
+
+	finish_reservation(c);
+	if (!allocated)
+		mutex_unlock(&c->write_reserve_mutex);
+	else
+		kfree(data);
+	return 0;
+
+out_release:
+	release_head(c, DATAHD);
+out_ro:
+	ubifs_ro_mode(c, err);
+	finish_reservation(c);
+out_free:
+	if (!allocated)
+		mutex_unlock(&c->write_reserve_mutex);
+	else
+		kfree(data);
+	return err;
+}
+
+/**
+ * ubifs_jnl_write_inode - flush inode to the journal.
+ * @c: UBIFS file-system description object
+ * @inode: inode to flush
+ *
+ * This function writes inode @inode to the journal. If the inode is
+ * synchronous, it also synchronizes the write-buffer. Returns zero in case of
+ * success and a negative error code in case of failure.
+ */
+int ubifs_jnl_write_inode(struct ubifs_info *c, const struct inode *inode)
+{
+	int err, lnum, offs;
+	struct ubifs_ino_node *ino;
+	struct ubifs_inode *ui = ubifs_inode(inode);
+	int sync = 0, len = UBIFS_INO_NODE_SZ, last_reference = !inode->i_nlink;
+
+	dbg_jnl("ino %lu, nlink %u", inode->i_ino, inode->i_nlink);
+
+	/*
+	 * If the inode is being deleted, do not write the attached data. No
+	 * need to synchronize the write-buffer either.
+	 */
+	if (!last_reference) {
+		len += ui->data_len;
+		sync = IS_SYNC(inode);
+	}
+	ino = kmalloc(len, GFP_NOFS);
+	if (!ino)
+		return -ENOMEM;
+
+	/* Make reservation before allocating sequence numbers */
+	err = make_reservation(c, BASEHD, len);
+	if (err)
+		goto out_free;
+
+	pack_inode(c, ino, inode, 1);
+	err = write_head(c, BASEHD, ino, len, &lnum, &offs, sync);
+	if (err)
+		goto out_release;
+	if (!sync)
+		ubifs_wbuf_add_ino_nolock(&c->jheads[BASEHD].wbuf,
+					  inode->i_ino);
+	release_head(c, BASEHD);
+
+	if (last_reference) {
+		err = ubifs_tnc_remove_ino(c, inode->i_ino);
+		if (err)
+			goto out_ro;
+		ubifs_delete_orphan(c, inode->i_ino);
+		err = ubifs_add_dirt(c, lnum, len);
+	} else {
+		union ubifs_key key;
+
+		ino_key_init(c, &key, inode->i_ino);
+		err = ubifs_tnc_add(c, &key, lnum, offs, len);
+	}
+	if (err)
+		goto out_ro;
+
+	finish_reservation(c);
+	spin_lock(&ui->ui_lock);
+	ui->synced_i_size = ui->ui_size;
+	spin_unlock(&ui->ui_lock);
+	kfree(ino);
+	return 0;
+
+out_release:
+	release_head(c, BASEHD);
+out_ro:
+	ubifs_ro_mode(c, err);
+	finish_reservation(c);
+out_free:
+	kfree(ino);
+	return err;
+}
+
+/**
+ * ubifs_jnl_delete_inode - delete an inode.
+ * @c: UBIFS file-system description object
+ * @inode: inode to delete
+ *
+ * This function deletes inode @inode which includes removing it from orphans,
+ * deleting it from TNC and, in some cases, writing a deletion inode to the
+ * journal.
+ *
+ * When regular file inodes are unlinked or a directory inode is removed, the
+ * 'ubifs_jnl_update()' function writes a corresponding deletion inode and
+ * direntry to the media, and adds the inode to orphans. After this, when the
+ * last reference to this inode has been dropped, this function is called. In
+ * general, it has to write one more deletion inode to the media, because if
+ * a commit happened between 'ubifs_jnl_update()' and
+ * 'ubifs_jnl_delete_inode()', the deletion inode is not in the journal
+ * anymore, and in fact it might not be on the flash anymore, because it might
+ * have been garbage-collected already. And for optimization reasons UBIFS does
+ * not read the orphan area if it has been unmounted cleanly, so it would have
+ * no indication in the journal that there is a deleted inode which has to be
+ * removed from TNC.
+ *
+ * However, if there was no commit between 'ubifs_jnl_update()' and
+ * 'ubifs_jnl_delete_inode()', then there is no need to write the deletion
+ * inode to the media for the second time. And this is quite a typical case.
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure.
+ */
+int ubifs_jnl_delete_inode(struct ubifs_info *c, const struct inode *inode)
+{
+	int err;
+	struct ubifs_inode *ui = ubifs_inode(inode);
+
+	ubifs_assert(inode->i_nlink == 0);
+
+	if (ui->del_cmtno != c->cmt_no)
+		/* A commit happened for sure */
+		return ubifs_jnl_write_inode(c, inode);
+
+	down_read(&c->commit_sem);
+	/*
+	 * Check commit number again, because the first test has been done
+	 * without @c->commit_sem, so a commit might have happened.
+	 */
+	if (ui->del_cmtno != c->cmt_no) {
+		up_read(&c->commit_sem);
+		return ubifs_jnl_write_inode(c, inode);
+	}
+
+	err = ubifs_tnc_remove_ino(c, inode->i_ino);
+	if (err)
+		ubifs_ro_mode(c, err);
+	else
+		ubifs_delete_orphan(c, inode->i_ino);
+	up_read(&c->commit_sem);
+	return err;
+}
+
+/**
+ * ubifs_jnl_rename - rename a directory entry.
+ * @c: UBIFS file-system description object
+ * @old_dir: parent inode of directory entry to rename
+ * @old_dentry: directory entry to rename
+ * @new_dir: parent inode of directory entry to rename
+ * @new_dentry: new directory entry (or directory entry to replace)
+ * @sync: non-zero if the write-buffer has to be synchronized
+ *
+ * This function implements the re-name operation which may involve writing up
+ * to 3 inodes and 2 directory entries. It marks the written inodes as clean
+ * and returns zero on success. In case of failure, a negative error code is
+ * returned.
+ */
+int ubifs_jnl_rename(struct ubifs_info *c, const struct inode *old_dir,
+		     const struct dentry *old_dentry,
+		     const struct inode *new_dir,
+		     const struct dentry *new_dentry, int sync)
+{
+	void *p;
+	union ubifs_key key;
+	struct ubifs_dent_node *dent, *dent2;
+	int err, dlen1, dlen2, ilen, lnum, offs, len;
+	const struct inode *old_inode = d_inode(old_dentry);
+	const struct inode *new_inode = d_inode(new_dentry);
+	int aligned_dlen1, aligned_dlen2, plen = UBIFS_INO_NODE_SZ;
+	int last_reference = !!(new_inode && new_inode->i_nlink == 0);
+	int move = (old_dir != new_dir);
+	struct ubifs_inode *uninitialized_var(new_ui);
+
+	dbg_jnl("dent '%pd' in dir ino %lu to dent '%pd' in dir ino %lu",
+		old_dentry, old_dir->i_ino, new_dentry, new_dir->i_ino);
+	ubifs_assert(ubifs_inode(old_dir)->data_len == 0);
+	ubifs_assert(ubifs_inode(new_dir)->data_len == 0);
+	ubifs_assert(mutex_is_locked(&ubifs_inode(old_dir)->ui_mutex));
+	ubifs_assert(mutex_is_locked(&ubifs_inode(new_dir)->ui_mutex));
+
+	dlen1 = UBIFS_DENT_NODE_SZ + new_dentry->d_name.len + 1;
+	dlen2 = UBIFS_DENT_NODE_SZ + old_dentry->d_name.len + 1;
+	if (new_inode) {
+		new_ui = ubifs_inode(new_inode);
+		ubifs_assert(mutex_is_locked(&new_ui->ui_mutex));
+		ilen = UBIFS_INO_NODE_SZ;
+		if (!last_reference)
+			ilen += new_ui->data_len;
+	} else
+		ilen = 0;
+
+	aligned_dlen1 = ALIGN(dlen1, 8);
+	aligned_dlen2 = ALIGN(dlen2, 8);
+	len = aligned_dlen1 + aligned_dlen2 + ALIGN(ilen, 8) + ALIGN(plen, 8);
+	if (old_dir != new_dir)
+		len += plen;
+	dent = kmalloc(len, GFP_NOFS);
+	if (!dent)
+		return -ENOMEM;
+
+	/* Make reservation before allocating sequence numbers */
+	err = make_reservation(c, BASEHD, len);
+	if (err)
+		goto out_free;
+
+	/* Make new dent */
+	dent->ch.node_type = UBIFS_DENT_NODE;
+	dent_key_init_flash(c, &dent->key, new_dir->i_ino, &new_dentry->d_name);
+	dent->inum = cpu_to_le64(old_inode->i_ino);
+	dent->type = get_dent_type(old_inode->i_mode);
+	dent->nlen = cpu_to_le16(new_dentry->d_name.len);
+	memcpy(dent->name, new_dentry->d_name.name, new_dentry->d_name.len);
+	dent->name[new_dentry->d_name.len] = '\0';
+	zero_dent_node_unused(dent);
+	ubifs_prep_grp_node(c, dent, dlen1, 0);
+
+	/* Make deletion dent */
+	dent2 = (void *)dent + aligned_dlen1;
+	dent2->ch.node_type = UBIFS_DENT_NODE;
+	dent_key_init_flash(c, &dent2->key, old_dir->i_ino,
+			    &old_dentry->d_name);
+	dent2->inum = 0;
+	dent2->type = DT_UNKNOWN;
+	dent2->nlen = cpu_to_le16(old_dentry->d_name.len);
+	memcpy(dent2->name, old_dentry->d_name.name, old_dentry->d_name.len);
+	dent2->name[old_dentry->d_name.len] = '\0';
+	zero_dent_node_unused(dent2);
+	ubifs_prep_grp_node(c, dent2, dlen2, 0);
+
+	p = (void *)dent2 + aligned_dlen2;
+	if (new_inode) {
+		pack_inode(c, p, new_inode, 0);
+		p += ALIGN(ilen, 8);
+	}
+
+	if (!move)
+		pack_inode(c, p, old_dir, 1);
+	else {
+		pack_inode(c, p, old_dir, 0);
+		p += ALIGN(plen, 8);
+		pack_inode(c, p, new_dir, 1);
+	}
+
+	if (last_reference) {
+		err = ubifs_add_orphan(c, new_inode->i_ino);
+		if (err) {
+			release_head(c, BASEHD);
+			goto out_finish;
+		}
+		new_ui->del_cmtno = c->cmt_no;
+	}
+
+	err = write_head(c, BASEHD, dent, len, &lnum, &offs, sync);
+	if (err)
+		goto out_release;
+	if (!sync) {
+		struct ubifs_wbuf *wbuf = &c->jheads[BASEHD].wbuf;
+
+		ubifs_wbuf_add_ino_nolock(wbuf, new_dir->i_ino);
+		ubifs_wbuf_add_ino_nolock(wbuf, old_dir->i_ino);
+		if (new_inode)
+			ubifs_wbuf_add_ino_nolock(&c->jheads[BASEHD].wbuf,
+						  new_inode->i_ino);
+	}
+	release_head(c, BASEHD);
+
+	dent_key_init(c, &key, new_dir->i_ino, &new_dentry->d_name);
+	err = ubifs_tnc_add_nm(c, &key, lnum, offs, dlen1, &new_dentry->d_name);
+	if (err)
+		goto out_ro;
+
+	err = ubifs_add_dirt(c, lnum, dlen2);
+	if (err)
+		goto out_ro;
+
+	dent_key_init(c, &key, old_dir->i_ino, &old_dentry->d_name);
+	err = ubifs_tnc_remove_nm(c, &key, &old_dentry->d_name);
+	if (err)
+		goto out_ro;
+
+	offs += aligned_dlen1 + aligned_dlen2;
+	if (new_inode) {
+		ino_key_init(c, &key, new_inode->i_ino);
+		err = ubifs_tnc_add(c, &key, lnum, offs, ilen);
+		if (err)
+			goto out_ro;
+		offs += ALIGN(ilen, 8);
+	}
+
+	ino_key_init(c, &key, old_dir->i_ino);
+	err = ubifs_tnc_add(c, &key, lnum, offs, plen);
+	if (err)
+		goto out_ro;
+
+	if (old_dir != new_dir) {
+		offs += ALIGN(plen, 8);
+		ino_key_init(c, &key, new_dir->i_ino);
+		err = ubifs_tnc_add(c, &key, lnum, offs, plen);
+		if (err)
+			goto out_ro;
+	}
+
+	finish_reservation(c);
+	if (new_inode) {
+		mark_inode_clean(c, new_ui);
+		spin_lock(&new_ui->ui_lock);
+		new_ui->synced_i_size = new_ui->ui_size;
+		spin_unlock(&new_ui->ui_lock);
+	}
+	mark_inode_clean(c, ubifs_inode(old_dir));
+	if (move)
+		mark_inode_clean(c, ubifs_inode(new_dir));
+	kfree(dent);
+	return 0;
+
+out_release:
+	release_head(c, BASEHD);
+out_ro:
+	ubifs_ro_mode(c, err);
+	if (last_reference)
+		ubifs_delete_orphan(c, new_inode->i_ino);
+out_finish:
+	finish_reservation(c);
+out_free:
+	kfree(dent);
+	return err;
+}
+
+/**
+ * recomp_data_node - re-compress a truncated data node.
+ * @dn: data node to re-compress
+ * @new_len: new length
+ *
+ * This function is used when an inode is truncated and the last data node of
+ * the inode has to be re-compressed and re-written.
+ */
+static int recomp_data_node(const struct ubifs_info *c,
+			    struct ubifs_data_node *dn, int *new_len)
+{
+	void *buf;
+	int err, len, compr_type, out_len;
+
+	out_len = le32_to_cpu(dn->size);
+	buf = kmalloc(out_len * WORST_COMPR_FACTOR, GFP_NOFS);
+	if (!buf)
+		return -ENOMEM;
+
+	len = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ;
+	compr_type = le16_to_cpu(dn->compr_type);
+	err = ubifs_decompress(c, &dn->data, len, buf, &out_len, compr_type);
+	if (err)
+		goto out;
+
+	ubifs_compress(c, buf, *new_len, &dn->data, &out_len, &compr_type);
+	ubifs_assert(out_len <= UBIFS_BLOCK_SIZE);
+	dn->compr_type = cpu_to_le16(compr_type);
+	dn->size = cpu_to_le32(*new_len);
+	*new_len = UBIFS_DATA_NODE_SZ + out_len;
+out:
+	kfree(buf);
+	return err;
+}
+
+/**
+ * ubifs_jnl_truncate - update the journal for a truncation.
+ * @c: UBIFS file-system description object
+ * @inode: inode to truncate
+ * @old_size: old size
+ * @new_size: new size
+ *
+ * When the size of a file decreases due to truncation, a truncation node is
+ * written, the journal tree is updated, and the last data block is re-written
+ * if it has been affected. The inode is also updated in order to synchronize
+ * the new inode size.
+ *
+ * This function marks the inode as clean and returns zero on success. In case
+ * of failure, a negative error code is returned.
+ */
+int ubifs_jnl_truncate(struct ubifs_info *c, const struct inode *inode,
+		       loff_t old_size, loff_t new_size)
+{
+	union ubifs_key key, to_key;
+	struct ubifs_ino_node *ino;
+	struct ubifs_trun_node *trun;
+	struct ubifs_data_node *uninitialized_var(dn);
+	int err, dlen, len, lnum, offs, bit, sz, sync = IS_SYNC(inode);
+	struct ubifs_inode *ui = ubifs_inode(inode);
+	ino_t inum = inode->i_ino;
+	unsigned int blk;
+
+	dbg_jnl("ino %lu, size %lld -> %lld",
+		(unsigned long)inum, old_size, new_size);
+	ubifs_assert(!ui->data_len);
+	ubifs_assert(S_ISREG(inode->i_mode));
+	ubifs_assert(mutex_is_locked(&ui->ui_mutex));
+
+	sz = UBIFS_TRUN_NODE_SZ + UBIFS_INO_NODE_SZ +
+	     UBIFS_MAX_DATA_NODE_SZ * WORST_COMPR_FACTOR;
+	ino = kmalloc(sz, GFP_NOFS);
+	if (!ino)
+		return -ENOMEM;
+
+	trun = (void *)ino + UBIFS_INO_NODE_SZ;
+	trun->ch.node_type = UBIFS_TRUN_NODE;
+	trun->inum = cpu_to_le32(inum);
+	trun->old_size = cpu_to_le64(old_size);
+	trun->new_size = cpu_to_le64(new_size);
+	zero_trun_node_unused(trun);
+
+	dlen = new_size & (UBIFS_BLOCK_SIZE - 1);
+	if (dlen) {
+		/* Get last data block so it can be truncated */
+		dn = (void *)trun + UBIFS_TRUN_NODE_SZ;
+		blk = new_size >> UBIFS_BLOCK_SHIFT;
+		data_key_init(c, &key, inum, blk);
+		dbg_jnlk(&key, "last block key ");
+		err = ubifs_tnc_lookup(c, &key, dn);
+		if (err == -ENOENT)
+			dlen = 0; /* Not found (so it is a hole) */
+		else if (err)
+			goto out_free;
+		else {
+			if (le32_to_cpu(dn->size) <= dlen)
+				dlen = 0; /* Nothing to do */
+			else {
+				int compr_type = le16_to_cpu(dn->compr_type);
+
+				if (compr_type != UBIFS_COMPR_NONE) {
+					err = recomp_data_node(c, dn, &dlen);
+					if (err)
+						goto out_free;
+				} else {
+					dn->size = cpu_to_le32(dlen);
+					dlen += UBIFS_DATA_NODE_SZ;
+				}
+				zero_data_node_unused(dn);
+			}
+		}
+	}
+
+	/* Must make reservation before allocating sequence numbers */
+	len = UBIFS_TRUN_NODE_SZ + UBIFS_INO_NODE_SZ;
+	if (dlen)
+		len += dlen;
+	err = make_reservation(c, BASEHD, len);
+	if (err)
+		goto out_free;
+
+	pack_inode(c, ino, inode, 0);
+	ubifs_prep_grp_node(c, trun, UBIFS_TRUN_NODE_SZ, dlen ? 0 : 1);
+	if (dlen)
+		ubifs_prep_grp_node(c, dn, dlen, 1);
+
+	err = write_head(c, BASEHD, ino, len, &lnum, &offs, sync);
+	if (err)
+		goto out_release;
+	if (!sync)
+		ubifs_wbuf_add_ino_nolock(&c->jheads[BASEHD].wbuf, inum);
+	release_head(c, BASEHD);
+
+	if (dlen) {
+		sz = offs + UBIFS_INO_NODE_SZ + UBIFS_TRUN_NODE_SZ;
+		err = ubifs_tnc_add(c, &key, lnum, sz, dlen);
+		if (err)
+			goto out_ro;
+	}
+
+	ino_key_init(c, &key, inum);
+	err = ubifs_tnc_add(c, &key, lnum, offs, UBIFS_INO_NODE_SZ);
+	if (err)
+		goto out_ro;
+
+	err = ubifs_add_dirt(c, lnum, UBIFS_TRUN_NODE_SZ);
+	if (err)
+		goto out_ro;
+
+	bit = new_size & (UBIFS_BLOCK_SIZE - 1);
+	blk = (new_size >> UBIFS_BLOCK_SHIFT) + (bit ? 1 : 0);
+	data_key_init(c, &key, inum, blk);
+
+	bit = old_size & (UBIFS_BLOCK_SIZE - 1);
+	blk = (old_size >> UBIFS_BLOCK_SHIFT) - (bit ? 0 : 1);
+	data_key_init(c, &to_key, inum, blk);
+
+	err = ubifs_tnc_remove_range(c, &key, &to_key);
+	if (err)
+		goto out_ro;
+
+	finish_reservation(c);
+	spin_lock(&ui->ui_lock);
+	ui->synced_i_size = ui->ui_size;
+	spin_unlock(&ui->ui_lock);
+	mark_inode_clean(c, ui);
+	kfree(ino);
+	return 0;
+
+out_release:
+	release_head(c, BASEHD);
+out_ro:
+	ubifs_ro_mode(c, err);
+	finish_reservation(c);
+out_free:
+	kfree(ino);
+	return err;
+}
+
+
+/**
+ * ubifs_jnl_delete_xattr - delete an extended attribute.
+ * @c: UBIFS file-system description object
+ * @host: host inode
+ * @inode: extended attribute inode
+ * @nm: extended attribute entry name
+ *
+ * This function delete an extended attribute which is very similar to
+ * un-linking regular files - it writes a deletion xentry, a deletion inode and
+ * updates the target inode. Returns zero in case of success and a negative
+ * error code in case of failure.
+ */
+int ubifs_jnl_delete_xattr(struct ubifs_info *c, const struct inode *host,
+			   const struct inode *inode, const struct qstr *nm)
+{
+	int err, xlen, hlen, len, lnum, xent_offs, aligned_xlen;
+	struct ubifs_dent_node *xent;
+	struct ubifs_ino_node *ino;
+	union ubifs_key xent_key, key1, key2;
+	int sync = IS_DIRSYNC(host);
+	struct ubifs_inode *host_ui = ubifs_inode(host);
+
+	dbg_jnl("host %lu, xattr ino %lu, name '%s', data len %d",
+		host->i_ino, inode->i_ino, nm->name,
+		ubifs_inode(inode)->data_len);
+	ubifs_assert(inode->i_nlink == 0);
+	ubifs_assert(mutex_is_locked(&host_ui->ui_mutex));
+
+	/*
+	 * Since we are deleting the inode, we do not bother to attach any data
+	 * to it and assume its length is %UBIFS_INO_NODE_SZ.
+	 */
+	xlen = UBIFS_DENT_NODE_SZ + nm->len + 1;
+	aligned_xlen = ALIGN(xlen, 8);
+	hlen = host_ui->data_len + UBIFS_INO_NODE_SZ;
+	len = aligned_xlen + UBIFS_INO_NODE_SZ + ALIGN(hlen, 8);
+
+	xent = kmalloc(len, GFP_NOFS);
+	if (!xent)
+		return -ENOMEM;
+
+	/* Make reservation before allocating sequence numbers */
+	err = make_reservation(c, BASEHD, len);
+	if (err) {
+		kfree(xent);
+		return err;
+	}
+
+	xent->ch.node_type = UBIFS_XENT_NODE;
+	xent_key_init(c, &xent_key, host->i_ino, nm);
+	key_write(c, &xent_key, xent->key);
+	xent->inum = 0;
+	xent->type = get_dent_type(inode->i_mode);
+	xent->nlen = cpu_to_le16(nm->len);
+	memcpy(xent->name, nm->name, nm->len);
+	xent->name[nm->len] = '\0';
+	zero_dent_node_unused(xent);
+	ubifs_prep_grp_node(c, xent, xlen, 0);
+
+	ino = (void *)xent + aligned_xlen;
+	pack_inode(c, ino, inode, 0);
+	ino = (void *)ino + UBIFS_INO_NODE_SZ;
+	pack_inode(c, ino, host, 1);
+
+	err = write_head(c, BASEHD, xent, len, &lnum, &xent_offs, sync);
+	if (!sync && !err)
+		ubifs_wbuf_add_ino_nolock(&c->jheads[BASEHD].wbuf, host->i_ino);
+	release_head(c, BASEHD);
+	kfree(xent);
+	if (err)
+		goto out_ro;
+
+	/* Remove the extended attribute entry from TNC */
+	err = ubifs_tnc_remove_nm(c, &xent_key, nm);
+	if (err)
+		goto out_ro;
+	err = ubifs_add_dirt(c, lnum, xlen);
+	if (err)
+		goto out_ro;
+
+	/*
+	 * Remove all nodes belonging to the extended attribute inode from TNC.
+	 * Well, there actually must be only one node - the inode itself.
+	 */
+	lowest_ino_key(c, &key1, inode->i_ino);
+	highest_ino_key(c, &key2, inode->i_ino);
+	err = ubifs_tnc_remove_range(c, &key1, &key2);
+	if (err)
+		goto out_ro;
+	err = ubifs_add_dirt(c, lnum, UBIFS_INO_NODE_SZ);
+	if (err)
+		goto out_ro;
+
+	/* And update TNC with the new host inode position */
+	ino_key_init(c, &key1, host->i_ino);
+	err = ubifs_tnc_add(c, &key1, lnum, xent_offs + len - hlen, hlen);
+	if (err)
+		goto out_ro;
+
+	finish_reservation(c);
+	spin_lock(&host_ui->ui_lock);
+	host_ui->synced_i_size = host_ui->ui_size;
+	spin_unlock(&host_ui->ui_lock);
+	mark_inode_clean(c, host_ui);
+	return 0;
+
+out_ro:
+	ubifs_ro_mode(c, err);
+	finish_reservation(c);
+	return err;
+}
+
+/**
+ * ubifs_jnl_change_xattr - change an extended attribute.
+ * @c: UBIFS file-system description object
+ * @inode: extended attribute inode
+ * @host: host inode
+ *
+ * This function writes the updated version of an extended attribute inode and
+ * the host inode to the journal (to the base head). The host inode is written
+ * after the extended attribute inode in order to guarantee that the extended
+ * attribute will be flushed when the inode is synchronized by 'fsync()' and
+ * consequently, the write-buffer is synchronized. This function returns zero
+ * in case of success and a negative error code in case of failure.
+ */
+int ubifs_jnl_change_xattr(struct ubifs_info *c, const struct inode *inode,
+			   const struct inode *host)
+{
+	int err, len1, len2, aligned_len, aligned_len1, lnum, offs;
+	struct ubifs_inode *host_ui = ubifs_inode(host);
+	struct ubifs_ino_node *ino;
+	union ubifs_key key;
+	int sync = IS_DIRSYNC(host);
+
+	dbg_jnl("ino %lu, ino %lu", host->i_ino, inode->i_ino);
+	ubifs_assert(host->i_nlink > 0);
+	ubifs_assert(inode->i_nlink > 0);
+	ubifs_assert(mutex_is_locked(&host_ui->ui_mutex));
+
+	len1 = UBIFS_INO_NODE_SZ + host_ui->data_len;
+	len2 = UBIFS_INO_NODE_SZ + ubifs_inode(inode)->data_len;
+	aligned_len1 = ALIGN(len1, 8);
+	aligned_len = aligned_len1 + ALIGN(len2, 8);
+
+	ino = kmalloc(aligned_len, GFP_NOFS);
+	if (!ino)
+		return -ENOMEM;
+
+	/* Make reservation before allocating sequence numbers */
+	err = make_reservation(c, BASEHD, aligned_len);
+	if (err)
+		goto out_free;
+
+	pack_inode(c, ino, host, 0);
+	pack_inode(c, (void *)ino + aligned_len1, inode, 1);
+
+	err = write_head(c, BASEHD, ino, aligned_len, &lnum, &offs, 0);
+	if (!sync && !err) {
+		struct ubifs_wbuf *wbuf = &c->jheads[BASEHD].wbuf;
+
+		ubifs_wbuf_add_ino_nolock(wbuf, host->i_ino);
+		ubifs_wbuf_add_ino_nolock(wbuf, inode->i_ino);
+	}
+	release_head(c, BASEHD);
+	if (err)
+		goto out_ro;
+
+	ino_key_init(c, &key, host->i_ino);
+	err = ubifs_tnc_add(c, &key, lnum, offs, len1);
+	if (err)
+		goto out_ro;
+
+	ino_key_init(c, &key, inode->i_ino);
+	err = ubifs_tnc_add(c, &key, lnum, offs + aligned_len1, len2);
+	if (err)
+		goto out_ro;
+
+	finish_reservation(c);
+	spin_lock(&host_ui->ui_lock);
+	host_ui->synced_i_size = host_ui->ui_size;
+	spin_unlock(&host_ui->ui_lock);
+	mark_inode_clean(c, host_ui);
+	kfree(ino);
+	return 0;
+
+out_ro:
+	ubifs_ro_mode(c, err);
+	finish_reservation(c);
+out_free:
+	kfree(ino);
+	return err;
+}
+