UBIFS: add new flash file system

This is a new flash file system. See
http://www.linux-mtd.infradead.org/doc/ubifs.html

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>

1 files changed, 1387 insertions, 0 deletions

diff --git a/fs/ubifs/journal.c b/fs/ubifs/journal.c
new file mode 100644
index 000000000000..283155abe5f5
--- /dev/null
+++ b/fs/ubifs/journal.c
@@ -0,0 +1,1387 @@
+/*
+ * 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, free, 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.
+         */
+        squeeze = (jhead == BASEHD);
+again:
+        mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
+
+        if (c->ro_media) {
+                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, &free, squeeze);
+        if (lnum >= 0) {
+                /* Found an LEB, add it to the journal head */
+                offs = c->leb_size - free;
+                err = ubifs_add_bud_to_log(c, jhead, lnum, offs);
+                if (err)
+                        goto out_return;
+                /* A new bud was successfully allocated and added to the log */
+                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  jhead %d, run GC", 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 %d", 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 %d", lnum, 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 then 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;
+        }
+
+        err = ubifs_add_bud_to_log(c, jhead, lnum, 0);
+        if (err)
+                goto out_return;
+        offs = 0;
+
+out:
+        err = ubifs_wbuf_seek_nolock(wbuf, lnum, offs, UBI_SHORTTERM);
+        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 %d, LEB %d:%d, len %d", 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 %d, LEB %d:%d, len %d", 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("stuck in space allocation");
+                err = -ENOSPC;
+                goto out;
+        } else if (cmt_retries > 32)
+                ubifs_warn("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("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);
+                spin_lock(&c->space_lock);
+                dbg_dump_stack();
+                dbg_dump_budg(c);
+                spin_unlock(&c->space_lock);
+                dbg_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
+ * @last_reference: non-zero if this is a deletion inode
+ */
+static void pack_inode(struct ubifs_info *c, struct ubifs_ino_node *ino,
+                       const struct inode *inode, int last,
+                       int last_reference)
+{
+        int data_len = 0;
+        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(inode->i_uid);
+        ino->gid   = cpu_to_le32(inode->i_gid);
+        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 *dir_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(dir_ui->data_len == 0);
+        ubifs_assert(mutex_is_locked(&dir_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;
+        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, last_reference);
+        ino = (void *)ino + aligned_ilen;
+        pack_inode(c, ino, dir, 1, 0);
+
+        if (last_reference) {
+                err = ubifs_add_orphan(c, inode->i_ino);
+                if (err) {
+                        release_head(c, BASEHD);
+                        goto out_finish;
+                }
+        }
+
+        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);
+        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, dir_ui);
+        return 0;
+
+out_finish:
+        finish_reservation(c);
+out_free:
+        kfree(dent);
+        return err;
+
+out_release:
+        release_head(c, BASEHD);
+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 = UBIFS_DATA_NODE_SZ + UBIFS_BLOCK_SIZE * WORST_COMPR_FACTOR;
+        struct ubifs_inode *ui = ubifs_inode(inode);
+
+        dbg_jnl("ino %lu, blk %u, len %d, key %s", key_inum(c, key),
+                key_block(c, key), len, DBGKEY(key));
+        ubifs_assert(len <= UBIFS_BLOCK_SIZE);
+
+        data = kmalloc(dlen, GFP_NOFS);
+        if (!data)
+                return -ENOMEM;
+
+        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(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);
+        kfree(data);
+        return 0;
+
+out_release:
+        release_head(c, DATAHD);
+out_ro:
+        ubifs_ro_mode(c, err);
+        finish_reservation(c);
+out_free:
+        kfree(data);
+        return err;
+}
+
+/**
+ * ubifs_jnl_write_inode - flush inode to the journal.
+ * @c: UBIFS file-system description object
+ * @inode: inode to flush
+ * @deletion: inode has been deleted
+ *
+ * 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 deletion)
+{
+        int err, len, lnum, offs, sync = 0;
+        struct ubifs_ino_node *ino;
+        struct ubifs_inode *ui = ubifs_inode(inode);
+
+        dbg_jnl("ino %lu%s", inode->i_ino,
+                deletion ? " (last reference)" : "");
+        if (deletion)
+                ubifs_assert(inode->i_nlink == 0);
+
+        len = UBIFS_INO_NODE_SZ;
+        /*
+         * If the inode is being deleted, do not write the attached data. No
+         * need to synchronize the write-buffer either.
+         */
+        if (!deletion) {
+                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, deletion);
+        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 (deletion) {
+                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_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 = old_dentry->d_inode;
+        const struct inode *new_inode = new_dentry->d_inode;
+        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 '%.*s' in dir ino %lu to dent '%.*s' in dir ino %lu",
+                old_dentry->d_name.len, old_dentry->d_name.name,
+                old_dir->i_ino, new_dentry->d_name.len,
+                new_dentry->d_name.name, 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, last_reference);
+                p += ALIGN(ilen, 8);
+        }
+
+        if (!move)
+                pack_inode(c, p, old_dir, 1, 0);
+        else {
+                pack_inode(c, p, old_dir, 0, 0);
+                p += ALIGN(plen, 8);
+                pack_inode(c, p, new_dir, 1, 0);
+        }
+
+        if (last_reference) {
+                err = ubifs_add_orphan(c, new_inode->i_ino);
+                if (err) {
+                        release_head(c, BASEHD);
+                        goto out_finish;
+                }
+        }
+
+        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(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(&dn->data, len, buf, &out_len, compr_type);
+        if (err)
+                goto out;
+
+        ubifs_compress(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", 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_jnl("last block key %s", DBGKEY(&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(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, 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;
+}
+
+#ifdef CONFIG_UBIFS_FS_XATTR
+
+/**
+ * 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, 1);
+        ino = (void *)ino + UBIFS_INO_NODE_SZ;
+        pack_inode(c, ino, host, 1, 0);
+
+        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 tho 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(inode);
+        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, 0);
+        pack_inode(c, (void *)ino + aligned_len1, inode, 1, 0);
+
+        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;
+}
+
+#endif /* CONFIG_UBIFS_FS_XATTR */