journal.c

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/*
 * 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"

static inline void zero_ino_node_unused(struct ubifs_ino_node *ino)
{
    memset(ino->padding1, 0, 4);
    memset(ino->padding2, 0, 26);
}

static inline void zero_dent_node_unused(struct ubifs_dent_node *dent)
{
    dent->padding1 = 0;
    memset(dent->padding2, 0, 4);
}

static inline void zero_data_node_unused(struct ubifs_data_node *data)
{
    memset(data->padding, 0, 2);
}

static inline void zero_trun_node_unused(struct ubifs_trun_node *trun)
{
    memset(trun->padding, 0, 12);
}

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;
}

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);
}

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;
}

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);
        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;
}

static inline void release_head(struct ubifs_info *c, int jhead)
{
    mutex_unlock(&c->jheads[jhead].wbuf.io_mutex);
}

static void finish_reservation(struct ubifs_info *c)
{
    up_read(&c->commit_sem);
}

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;
}

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);
}

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;
}

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);
    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);
    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);
    kfree(dent);
out_ro:
    ubifs_ro_mode(c, err);
    if (last_reference)
        ubifs_delete_orphan(c, inode->i_ino);
    finish_reservation(c);
    return err;
}

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(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;
}

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;
}

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;
}

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);
        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;
}

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;
}

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(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;
}


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;
}

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;
}