dir.c

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/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2001-2007 Red Hat, Inc.
 * Copyright © 2004-2010 David Woodhouse <[email protected]>
 *
 * Created by David Woodhouse <[email protected]>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/crc32.h>
#include <linux/jffs2.h>
#include "jffs2_fs_i.h"
#include "jffs2_fs_sb.h"
#include <linux/time.h>
#include "nodelist.h"

static int jffs2_readdir (struct file *, void *, filldir_t);

static int jffs2_create (struct inode *,struct dentry *,umode_t,
             bool);
static struct dentry *jffs2_lookup (struct inode *,struct dentry *,
                    unsigned int);
static int jffs2_link (struct dentry *,struct inode *,struct dentry *);
static int jffs2_unlink (struct inode *,struct dentry *);
static int jffs2_symlink (struct inode *,struct dentry *,const char *);
static int jffs2_mkdir (struct inode *,struct dentry *,umode_t);
static int jffs2_rmdir (struct inode *,struct dentry *);
static int jffs2_mknod (struct inode *,struct dentry *,umode_t,dev_t);
static int jffs2_rename (struct inode *, struct dentry *,
             struct inode *, struct dentry *);

const struct file_operations jffs2_dir_operations =
{
    .read =     generic_read_dir,
    .readdir =  jffs2_readdir,
    .unlocked_ioctl=jffs2_ioctl,
    .fsync =    jffs2_fsync,
    .llseek =   generic_file_llseek,
};


const struct inode_operations jffs2_dir_inode_operations =
{
    .create =   jffs2_create,
    .lookup =   jffs2_lookup,
    .link =     jffs2_link,
    .unlink =   jffs2_unlink,
    .symlink =  jffs2_symlink,
    .mkdir =    jffs2_mkdir,
    .rmdir =    jffs2_rmdir,
    .mknod =    jffs2_mknod,
    .rename =   jffs2_rename,
    .get_acl =  jffs2_get_acl,
    .setattr =  jffs2_setattr,
    .setxattr = jffs2_setxattr,
    .getxattr = jffs2_getxattr,
    .listxattr =    jffs2_listxattr,
    .removexattr =  jffs2_removexattr
};

/***********************************************************************/


/* We keep the dirent list sorted in increasing order of name hash,
   and we use the same hash function as the dentries. Makes this
   nice and simple
*/
static struct dentry *jffs2_lookup(struct inode *dir_i, struct dentry *target,
                   unsigned int flags)
{
    struct jffs2_inode_info *dir_f;
    struct jffs2_full_dirent *fd = NULL, *fd_list;
    uint32_t ino = 0;
    struct inode *inode = NULL;

    jffs2_dbg(1, "jffs2_lookup()\n");

    if (target->d_name.len > JFFS2_MAX_NAME_LEN)
        return ERR_PTR(-ENAMETOOLONG);

    dir_f = JFFS2_INODE_INFO(dir_i);

    mutex_lock(&dir_f->sem);

    /* NB: The 2.2 backport will need to explicitly check for '.' and '..' here */
    for (fd_list = dir_f->dents; fd_list && fd_list->nhash <= target->d_name.hash; fd_list = fd_list->next) {
        if (fd_list->nhash == target->d_name.hash &&
            (!fd || fd_list->version > fd->version) &&
            strlen(fd_list->name) == target->d_name.len &&
            !strncmp(fd_list->name, target->d_name.name, target->d_name.len)) {
            fd = fd_list;
        }
    }
    if (fd)
        ino = fd->ino;
    mutex_unlock(&dir_f->sem);
    if (ino) {
        inode = jffs2_iget(dir_i->i_sb, ino);
        if (IS_ERR(inode))
            pr_warn("iget() failed for ino #%u\n", ino);
    }

    return d_splice_alias(inode, target);
}

/***********************************************************************/


static int jffs2_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
    struct jffs2_inode_info *f;
    struct inode *inode = filp->f_path.dentry->d_inode;
    struct jffs2_full_dirent *fd;
    unsigned long offset, curofs;

    jffs2_dbg(1, "jffs2_readdir() for dir_i #%lu\n",
          filp->f_path.dentry->d_inode->i_ino);

    f = JFFS2_INODE_INFO(inode);

    offset = filp->f_pos;

    if (offset == 0) {
        jffs2_dbg(1, "Dirent 0: \".\", ino #%lu\n", inode->i_ino);
        if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
            goto out;
        offset++;
    }
    if (offset == 1) {
        unsigned long pino = parent_ino(filp->f_path.dentry);
        jffs2_dbg(1, "Dirent 1: \"..\", ino #%lu\n", pino);
        if (filldir(dirent, "..", 2, 1, pino, DT_DIR) < 0)
            goto out;
        offset++;
    }

    curofs=1;
    mutex_lock(&f->sem);
    for (fd = f->dents; fd; fd = fd->next) {

        curofs++;
        /* First loop: curofs = 2; offset = 2 */
        if (curofs < offset) {
            jffs2_dbg(2, "Skipping dirent: \"%s\", ino #%u, type %d, because curofs %ld < offset %ld\n",
                  fd->name, fd->ino, fd->type, curofs, offset);
            continue;
        }
        if (!fd->ino) {
            jffs2_dbg(2, "Skipping deletion dirent \"%s\"\n",
                  fd->name);
            offset++;
            continue;
        }
        jffs2_dbg(2, "Dirent %ld: \"%s\", ino #%u, type %d\n",
              offset, fd->name, fd->ino, fd->type);
        if (filldir(dirent, fd->name, strlen(fd->name), offset, fd->ino, fd->type) < 0)
            break;
        offset++;
    }
    mutex_unlock(&f->sem);
 out:
    filp->f_pos = offset;
    return 0;
}

/***********************************************************************/


static int jffs2_create(struct inode *dir_i, struct dentry *dentry,
            umode_t mode, bool excl)
{
    struct jffs2_raw_inode *ri;
    struct jffs2_inode_info *f, *dir_f;
    struct jffs2_sb_info *c;
    struct inode *inode;
    int ret;

    ri = jffs2_alloc_raw_inode();
    if (!ri)
        return -ENOMEM;

    c = JFFS2_SB_INFO(dir_i->i_sb);

    jffs2_dbg(1, "%s()\n", __func__);

    inode = jffs2_new_inode(dir_i, mode, ri);

    if (IS_ERR(inode)) {
        jffs2_dbg(1, "jffs2_new_inode() failed\n");
        jffs2_free_raw_inode(ri);
        return PTR_ERR(inode);
    }

    inode->i_op = &jffs2_file_inode_operations;
    inode->i_fop = &jffs2_file_operations;
    inode->i_mapping->a_ops = &jffs2_file_address_operations;
    inode->i_mapping->nrpages = 0;

    f = JFFS2_INODE_INFO(inode);
    dir_f = JFFS2_INODE_INFO(dir_i);

    /* jffs2_do_create() will want to lock it, _after_ reserving
       space and taking c-alloc_sem. If we keep it locked here,
       lockdep gets unhappy (although it's a false positive;
       nothing else will be looking at this inode yet so there's
       no chance of AB-BA deadlock involving its f->sem). */
    mutex_unlock(&f->sem);

    ret = jffs2_do_create(c, dir_f, f, ri, &dentry->d_name);
    if (ret)
        goto fail;

    dir_i->i_mtime = dir_i->i_ctime = ITIME(je32_to_cpu(ri->ctime));

    jffs2_free_raw_inode(ri);

    jffs2_dbg(1, "%s(): Created ino #%lu with mode %o, nlink %d(%d). nrpages %ld\n",
          __func__, inode->i_ino, inode->i_mode, inode->i_nlink,
          f->inocache->pino_nlink, inode->i_mapping->nrpages);

    unlock_new_inode(inode);
    d_instantiate(dentry, inode);
    return 0;

 fail:
    iget_failed(inode);
    jffs2_free_raw_inode(ri);
    return ret;
}

/***********************************************************************/


static int jffs2_unlink(struct inode *dir_i, struct dentry *dentry)
{
    struct jffs2_sb_info *c = JFFS2_SB_INFO(dir_i->i_sb);
    struct jffs2_inode_info *dir_f = JFFS2_INODE_INFO(dir_i);
    struct jffs2_inode_info *dead_f = JFFS2_INODE_INFO(dentry->d_inode);
    int ret;
    uint32_t now = get_seconds();

    ret = jffs2_do_unlink(c, dir_f, dentry->d_name.name,
                  dentry->d_name.len, dead_f, now);
    if (dead_f->inocache)
        set_nlink(dentry->d_inode, dead_f->inocache->pino_nlink);
    if (!ret)
        dir_i->i_mtime = dir_i->i_ctime = ITIME(now);
    return ret;
}
/***********************************************************************/


static int jffs2_link (struct dentry *old_dentry, struct inode *dir_i, struct dentry *dentry)
{
    struct jffs2_sb_info *c = JFFS2_SB_INFO(old_dentry->d_inode->i_sb);
    struct jffs2_inode_info *f = JFFS2_INODE_INFO(old_dentry->d_inode);
    struct jffs2_inode_info *dir_f = JFFS2_INODE_INFO(dir_i);
    int ret;
    uint8_t type;
    uint32_t now;

    /* Don't let people make hard links to bad inodes. */
    if (!f->inocache)
        return -EIO;

    if (S_ISDIR(old_dentry->d_inode->i_mode))
        return -EPERM;

    /* XXX: This is ugly */
    type = (old_dentry->d_inode->i_mode & S_IFMT) >> 12;
    if (!type) type = DT_REG;

    now = get_seconds();
    ret = jffs2_do_link(c, dir_f, f->inocache->ino, type, dentry->d_name.name, dentry->d_name.len, now);

    if (!ret) {
        mutex_lock(&f->sem);
        set_nlink(old_dentry->d_inode, ++f->inocache->pino_nlink);
        mutex_unlock(&f->sem);
        d_instantiate(dentry, old_dentry->d_inode);
        dir_i->i_mtime = dir_i->i_ctime = ITIME(now);
        ihold(old_dentry->d_inode);
    }
    return ret;
}

/***********************************************************************/

static int jffs2_symlink (struct inode *dir_i, struct dentry *dentry, const char *target)
{
    struct jffs2_inode_info *f, *dir_f;
    struct jffs2_sb_info *c;
    struct inode *inode;
    struct jffs2_raw_inode *ri;
    struct jffs2_raw_dirent *rd;
    struct jffs2_full_dnode *fn;
    struct jffs2_full_dirent *fd;
    int namelen;
    uint32_t alloclen;
    int ret, targetlen = strlen(target);

    /* FIXME: If you care. We'd need to use frags for the target
       if it grows much more than this */
    if (targetlen > 254)
        return -ENAMETOOLONG;

    ri = jffs2_alloc_raw_inode();

    if (!ri)
        return -ENOMEM;

    c = JFFS2_SB_INFO(dir_i->i_sb);

    /* Try to reserve enough space for both node and dirent.
     * Just the node will do for now, though
     */
    namelen = dentry->d_name.len;
    ret = jffs2_reserve_space(c, sizeof(*ri) + targetlen, &alloclen,
                  ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);

    if (ret) {
        jffs2_free_raw_inode(ri);
        return ret;
    }

    inode = jffs2_new_inode(dir_i, S_IFLNK | S_IRWXUGO, ri);

    if (IS_ERR(inode)) {
        jffs2_free_raw_inode(ri);
        jffs2_complete_reservation(c);
        return PTR_ERR(inode);
    }

    inode->i_op = &jffs2_symlink_inode_operations;

    f = JFFS2_INODE_INFO(inode);

    inode->i_size = targetlen;
    ri->isize = ri->dsize = ri->csize = cpu_to_je32(inode->i_size);
    ri->totlen = cpu_to_je32(sizeof(*ri) + inode->i_size);
    ri->hdr_crc = cpu_to_je32(crc32(0, ri, sizeof(struct jffs2_unknown_node)-4));

    ri->compr = JFFS2_COMPR_NONE;
    ri->data_crc = cpu_to_je32(crc32(0, target, targetlen));
    ri->node_crc = cpu_to_je32(crc32(0, ri, sizeof(*ri)-8));

    fn = jffs2_write_dnode(c, f, ri, target, targetlen, ALLOC_NORMAL);

    jffs2_free_raw_inode(ri);

    if (IS_ERR(fn)) {
        /* Eeek. Wave bye bye */
        mutex_unlock(&f->sem);
        jffs2_complete_reservation(c);
        ret = PTR_ERR(fn);
        goto fail;
    }

    /* We use f->target field to store the target path. */
    f->target = kmemdup(target, targetlen + 1, GFP_KERNEL);
    if (!f->target) {
        pr_warn("Can't allocate %d bytes of memory\n", targetlen + 1);
        mutex_unlock(&f->sem);
        jffs2_complete_reservation(c);
        ret = -ENOMEM;
        goto fail;
    }

    jffs2_dbg(1, "%s(): symlink's target '%s' cached\n",
          __func__, (char *)f->target);

    /* No data here. Only a metadata node, which will be
       obsoleted by the first data write
    */
    f->metadata = fn;
    mutex_unlock(&f->sem);

    jffs2_complete_reservation(c);

    ret = jffs2_init_security(inode, dir_i, &dentry->d_name);
    if (ret)
        goto fail;

    ret = jffs2_init_acl_post(inode);
    if (ret)
        goto fail;

    ret = jffs2_reserve_space(c, sizeof(*rd)+namelen, &alloclen,
                  ALLOC_NORMAL, JFFS2_SUMMARY_DIRENT_SIZE(namelen));
    if (ret)
        goto fail;

    rd = jffs2_alloc_raw_dirent();
    if (!rd) {
        /* Argh. Now we treat it like a normal delete */
        jffs2_complete_reservation(c);
        ret = -ENOMEM;
        goto fail;
    }

    dir_f = JFFS2_INODE_INFO(dir_i);
    mutex_lock(&dir_f->sem);

    rd->magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
    rd->nodetype = cpu_to_je16(JFFS2_NODETYPE_DIRENT);
    rd->totlen = cpu_to_je32(sizeof(*rd) + namelen);
    rd->hdr_crc = cpu_to_je32(crc32(0, rd, sizeof(struct jffs2_unknown_node)-4));

    rd->pino = cpu_to_je32(dir_i->i_ino);
    rd->version = cpu_to_je32(++dir_f->highest_version);
    rd->ino = cpu_to_je32(inode->i_ino);
    rd->mctime = cpu_to_je32(get_seconds());
    rd->nsize = namelen;
    rd->type = DT_LNK;
    rd->node_crc = cpu_to_je32(crc32(0, rd, sizeof(*rd)-8));
    rd->name_crc = cpu_to_je32(crc32(0, dentry->d_name.name, namelen));

    fd = jffs2_write_dirent(c, dir_f, rd, dentry->d_name.name, namelen, ALLOC_NORMAL);

    if (IS_ERR(fd)) {
        /* dirent failed to write. Delete the inode normally
           as if it were the final unlink() */
        jffs2_complete_reservation(c);
        jffs2_free_raw_dirent(rd);
        mutex_unlock(&dir_f->sem);
        ret = PTR_ERR(fd);
        goto fail;
    }

    dir_i->i_mtime = dir_i->i_ctime = ITIME(je32_to_cpu(rd->mctime));

    jffs2_free_raw_dirent(rd);

    /* Link the fd into the inode's list, obsoleting an old
       one if necessary. */
    jffs2_add_fd_to_list(c, fd, &dir_f->dents);

    mutex_unlock(&dir_f->sem);
    jffs2_complete_reservation(c);

    unlock_new_inode(inode);
    d_instantiate(dentry, inode);
    return 0;

 fail:
    iget_failed(inode);
    return ret;
}


static int jffs2_mkdir (struct inode *dir_i, struct dentry *dentry, umode_t mode)
{
    struct jffs2_inode_info *f, *dir_f;
    struct jffs2_sb_info *c;
    struct inode *inode;
    struct jffs2_raw_inode *ri;
    struct jffs2_raw_dirent *rd;
    struct jffs2_full_dnode *fn;
    struct jffs2_full_dirent *fd;
    int namelen;
    uint32_t alloclen;
    int ret;

    mode |= S_IFDIR;

    ri = jffs2_alloc_raw_inode();
    if (!ri)
        return -ENOMEM;

    c = JFFS2_SB_INFO(dir_i->i_sb);

    /* Try to reserve enough space for both node and dirent.
     * Just the node will do for now, though
     */
    namelen = dentry->d_name.len;
    ret = jffs2_reserve_space(c, sizeof(*ri), &alloclen, ALLOC_NORMAL,
                  JFFS2_SUMMARY_INODE_SIZE);

    if (ret) {
        jffs2_free_raw_inode(ri);
        return ret;
    }

    inode = jffs2_new_inode(dir_i, mode, ri);

    if (IS_ERR(inode)) {
        jffs2_free_raw_inode(ri);
        jffs2_complete_reservation(c);
        return PTR_ERR(inode);
    }

    inode->i_op = &jffs2_dir_inode_operations;
    inode->i_fop = &jffs2_dir_operations;

    f = JFFS2_INODE_INFO(inode);

    /* Directories get nlink 2 at start */
    set_nlink(inode, 2);
    /* but ic->pino_nlink is the parent ino# */
    f->inocache->pino_nlink = dir_i->i_ino;

    ri->data_crc = cpu_to_je32(0);
    ri->node_crc = cpu_to_je32(crc32(0, ri, sizeof(*ri)-8));

    fn = jffs2_write_dnode(c, f, ri, NULL, 0, ALLOC_NORMAL);

    jffs2_free_raw_inode(ri);

    if (IS_ERR(fn)) {
        /* Eeek. Wave bye bye */
        mutex_unlock(&f->sem);
        jffs2_complete_reservation(c);
        ret = PTR_ERR(fn);
        goto fail;
    }
    /* No data here. Only a metadata node, which will be
       obsoleted by the first data write
    */
    f->metadata = fn;
    mutex_unlock(&f->sem);

    jffs2_complete_reservation(c);

    ret = jffs2_init_security(inode, dir_i, &dentry->d_name);
    if (ret)
        goto fail;

    ret = jffs2_init_acl_post(inode);
    if (ret)
        goto fail;

    ret = jffs2_reserve_space(c, sizeof(*rd)+namelen, &alloclen,
                  ALLOC_NORMAL, JFFS2_SUMMARY_DIRENT_SIZE(namelen));
    if (ret)
        goto fail;

    rd = jffs2_alloc_raw_dirent();
    if (!rd) {
        /* Argh. Now we treat it like a normal delete */
        jffs2_complete_reservation(c);
        ret = -ENOMEM;
        goto fail;
    }

    dir_f = JFFS2_INODE_INFO(dir_i);
    mutex_lock(&dir_f->sem);

    rd->magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
    rd->nodetype = cpu_to_je16(JFFS2_NODETYPE_DIRENT);
    rd->totlen = cpu_to_je32(sizeof(*rd) + namelen);
    rd->hdr_crc = cpu_to_je32(crc32(0, rd, sizeof(struct jffs2_unknown_node)-4));

    rd->pino = cpu_to_je32(dir_i->i_ino);
    rd->version = cpu_to_je32(++dir_f->highest_version);
    rd->ino = cpu_to_je32(inode->i_ino);
    rd->mctime = cpu_to_je32(get_seconds());
    rd->nsize = namelen;
    rd->type = DT_DIR;
    rd->node_crc = cpu_to_je32(crc32(0, rd, sizeof(*rd)-8));
    rd->name_crc = cpu_to_je32(crc32(0, dentry->d_name.name, namelen));

    fd = jffs2_write_dirent(c, dir_f, rd, dentry->d_name.name, namelen, ALLOC_NORMAL);

    if (IS_ERR(fd)) {
        /* dirent failed to write. Delete the inode normally
           as if it were the final unlink() */
        jffs2_complete_reservation(c);
        jffs2_free_raw_dirent(rd);
        mutex_unlock(&dir_f->sem);
        ret = PTR_ERR(fd);
        goto fail;
    }

    dir_i->i_mtime = dir_i->i_ctime = ITIME(je32_to_cpu(rd->mctime));
    inc_nlink(dir_i);

    jffs2_free_raw_dirent(rd);

    /* Link the fd into the inode's list, obsoleting an old
       one if necessary. */
    jffs2_add_fd_to_list(c, fd, &dir_f->dents);

    mutex_unlock(&dir_f->sem);
    jffs2_complete_reservation(c);

    unlock_new_inode(inode);
    d_instantiate(dentry, inode);
    return 0;

 fail:
    iget_failed(inode);
    return ret;
}

static int jffs2_rmdir (struct inode *dir_i, struct dentry *dentry)
{
    struct jffs2_sb_info *c = JFFS2_SB_INFO(dir_i->i_sb);
    struct jffs2_inode_info *dir_f = JFFS2_INODE_INFO(dir_i);
    struct jffs2_inode_info *f = JFFS2_INODE_INFO(dentry->d_inode);
    struct jffs2_full_dirent *fd;
    int ret;
    uint32_t now = get_seconds();

    for (fd = f->dents ; fd; fd = fd->next) {
        if (fd->ino)
            return -ENOTEMPTY;
    }

    ret = jffs2_do_unlink(c, dir_f, dentry->d_name.name,
                  dentry->d_name.len, f, now);
    if (!ret) {
        dir_i->i_mtime = dir_i->i_ctime = ITIME(now);
        clear_nlink(dentry->d_inode);
        drop_nlink(dir_i);
    }
    return ret;
}

static int jffs2_mknod (struct inode *dir_i, struct dentry *dentry, umode_t mode, dev_t rdev)
{
    struct jffs2_inode_info *f, *dir_f;
    struct jffs2_sb_info *c;
    struct inode *inode;
    struct jffs2_raw_inode *ri;
    struct jffs2_raw_dirent *rd;
    struct jffs2_full_dnode *fn;
    struct jffs2_full_dirent *fd;
    int namelen;
    union jffs2_device_node dev;
    int devlen = 0;
    uint32_t alloclen;
    int ret;

    if (!new_valid_dev(rdev))
        return -EINVAL;

    ri = jffs2_alloc_raw_inode();
    if (!ri)
        return -ENOMEM;

    c = JFFS2_SB_INFO(dir_i->i_sb);

    if (S_ISBLK(mode) || S_ISCHR(mode))
        devlen = jffs2_encode_dev(&dev, rdev);

    /* Try to reserve enough space for both node and dirent.
     * Just the node will do for now, though
     */
    namelen = dentry->d_name.len;
    ret = jffs2_reserve_space(c, sizeof(*ri) + devlen, &alloclen,
                  ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);

    if (ret) {
        jffs2_free_raw_inode(ri);
        return ret;
    }

    inode = jffs2_new_inode(dir_i, mode, ri);

    if (IS_ERR(inode)) {
        jffs2_free_raw_inode(ri);
        jffs2_complete_reservation(c);
        return PTR_ERR(inode);
    }
    inode->i_op = &jffs2_file_inode_operations;
    init_special_inode(inode, inode->i_mode, rdev);

    f = JFFS2_INODE_INFO(inode);

    ri->dsize = ri->csize = cpu_to_je32(devlen);
    ri->totlen = cpu_to_je32(sizeof(*ri) + devlen);
    ri->hdr_crc = cpu_to_je32(crc32(0, ri, sizeof(struct jffs2_unknown_node)-4));

    ri->compr = JFFS2_COMPR_NONE;
    ri->data_crc = cpu_to_je32(crc32(0, &dev, devlen));
    ri->node_crc = cpu_to_je32(crc32(0, ri, sizeof(*ri)-8));

    fn = jffs2_write_dnode(c, f, ri, (char *)&dev, devlen, ALLOC_NORMAL);

    jffs2_free_raw_inode(ri);

    if (IS_ERR(fn)) {
        /* Eeek. Wave bye bye */
        mutex_unlock(&f->sem);
        jffs2_complete_reservation(c);
        ret = PTR_ERR(fn);
        goto fail;
    }
    /* No data here. Only a metadata node, which will be
       obsoleted by the first data write
    */
    f->metadata = fn;
    mutex_unlock(&f->sem);

    jffs2_complete_reservation(c);

    ret = jffs2_init_security(inode, dir_i, &dentry->d_name);
    if (ret)
        goto fail;

    ret = jffs2_init_acl_post(inode);
    if (ret)
        goto fail;

    ret = jffs2_reserve_space(c, sizeof(*rd)+namelen, &alloclen,
                  ALLOC_NORMAL, JFFS2_SUMMARY_DIRENT_SIZE(namelen));
    if (ret)
        goto fail;

    rd = jffs2_alloc_raw_dirent();
    if (!rd) {
        /* Argh. Now we treat it like a normal delete */
        jffs2_complete_reservation(c);
        ret = -ENOMEM;
        goto fail;
    }

    dir_f = JFFS2_INODE_INFO(dir_i);
    mutex_lock(&dir_f->sem);

    rd->magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
    rd->nodetype = cpu_to_je16(JFFS2_NODETYPE_DIRENT);
    rd->totlen = cpu_to_je32(sizeof(*rd) + namelen);
    rd->hdr_crc = cpu_to_je32(crc32(0, rd, sizeof(struct jffs2_unknown_node)-4));

    rd->pino = cpu_to_je32(dir_i->i_ino);
    rd->version = cpu_to_je32(++dir_f->highest_version);
    rd->ino = cpu_to_je32(inode->i_ino);
    rd->mctime = cpu_to_je32(get_seconds());
    rd->nsize = namelen;

    /* XXX: This is ugly. */
    rd->type = (mode & S_IFMT) >> 12;

    rd->node_crc = cpu_to_je32(crc32(0, rd, sizeof(*rd)-8));
    rd->name_crc = cpu_to_je32(crc32(0, dentry->d_name.name, namelen));

    fd = jffs2_write_dirent(c, dir_f, rd, dentry->d_name.name, namelen, ALLOC_NORMAL);

    if (IS_ERR(fd)) {
        /* dirent failed to write. Delete the inode normally
           as if it were the final unlink() */
        jffs2_complete_reservation(c);
        jffs2_free_raw_dirent(rd);
        mutex_unlock(&dir_f->sem);
        ret = PTR_ERR(fd);
        goto fail;
    }

    dir_i->i_mtime = dir_i->i_ctime = ITIME(je32_to_cpu(rd->mctime));

    jffs2_free_raw_dirent(rd);

    /* Link the fd into the inode's list, obsoleting an old
       one if necessary. */
    jffs2_add_fd_to_list(c, fd, &dir_f->dents);

    mutex_unlock(&dir_f->sem);
    jffs2_complete_reservation(c);

    unlock_new_inode(inode);
    d_instantiate(dentry, inode);
    return 0;

 fail:
    iget_failed(inode);
    return ret;
}

static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,
             struct inode *new_dir_i, struct dentry *new_dentry)
{
    int ret;
    struct jffs2_sb_info *c = JFFS2_SB_INFO(old_dir_i->i_sb);
    struct jffs2_inode_info *victim_f = NULL;
    uint8_t type;
    uint32_t now;

    /* The VFS will check for us and prevent trying to rename a
     * file over a directory and vice versa, but if it's a directory,
     * the VFS can't check whether the victim is empty. The filesystem
     * needs to do that for itself.
     */
    if (new_dentry->d_inode) {
        victim_f = JFFS2_INODE_INFO(new_dentry->d_inode);
        if (S_ISDIR(new_dentry->d_inode->i_mode)) {
            struct jffs2_full_dirent *fd;

            mutex_lock(&victim_f->sem);
            for (fd = victim_f->dents; fd; fd = fd->next) {
                if (fd->ino) {
                    mutex_unlock(&victim_f->sem);
                    return -ENOTEMPTY;
                }
            }
            mutex_unlock(&victim_f->sem);
        }
    }

    /* XXX: We probably ought to alloc enough space for
       both nodes at the same time. Writing the new link,
       then getting -ENOSPC, is quite bad :)
    */

    /* Make a hard link */

    /* XXX: This is ugly */
    type = (old_dentry->d_inode->i_mode & S_IFMT) >> 12;
    if (!type) type = DT_REG;

    now = get_seconds();
    ret = jffs2_do_link(c, JFFS2_INODE_INFO(new_dir_i),
                old_dentry->d_inode->i_ino, type,
                new_dentry->d_name.name, new_dentry->d_name.len, now);

    if (ret)
        return ret;

    if (victim_f) {
        /* There was a victim. Kill it off nicely */
        if (S_ISDIR(new_dentry->d_inode->i_mode))
            clear_nlink(new_dentry->d_inode);
        else
            drop_nlink(new_dentry->d_inode);
        /* Don't oops if the victim was a dirent pointing to an
           inode which didn't exist. */
        if (victim_f->inocache) {
            mutex_lock(&victim_f->sem);
            if (S_ISDIR(new_dentry->d_inode->i_mode))
                victim_f->inocache->pino_nlink = 0;
            else
                victim_f->inocache->pino_nlink--;
            mutex_unlock(&victim_f->sem);
        }
    }

    /* If it was a directory we moved, and there was no victim,
       increase i_nlink on its new parent */
    if (S_ISDIR(old_dentry->d_inode->i_mode) && !victim_f)
        inc_nlink(new_dir_i);

    /* Unlink the original */
    ret = jffs2_do_unlink(c, JFFS2_INODE_INFO(old_dir_i),
                  old_dentry->d_name.name, old_dentry->d_name.len, NULL, now);

    /* We don't touch inode->i_nlink */

    if (ret) {
        /* Oh shit. We really ought to make a single node which can do both atomically */
        struct jffs2_inode_info *f = JFFS2_INODE_INFO(old_dentry->d_inode);
        mutex_lock(&f->sem);
        inc_nlink(old_dentry->d_inode);
        if (f->inocache && !S_ISDIR(old_dentry->d_inode->i_mode))
            f->inocache->pino_nlink++;
        mutex_unlock(&f->sem);

        pr_notice("%s(): Link succeeded, unlink failed (err %d). You now have a hard link\n",
              __func__, ret);
        /* Might as well let the VFS know */
        d_instantiate(new_dentry, old_dentry->d_inode);
        ihold(old_dentry->d_inode);
        new_dir_i->i_mtime = new_dir_i->i_ctime = ITIME(now);
        return ret;
    }

    if (S_ISDIR(old_dentry->d_inode->i_mode))
        drop_nlink(old_dir_i);

    new_dir_i->i_mtime = new_dir_i->i_ctime = old_dir_i->i_mtime = old_dir_i->i_ctime = ITIME(now);

    return 0;
}