/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2001-2007 Red Hat, Inc.
 * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
 *
 * Created by David Woodhouse <dwmw2@infradead.org>
 *
 * 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 *, struct dir_context *);

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,
        .iterate =      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 *file, struct dir_context *ctx)
{
        struct inode *inode = file_inode(file);
        struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
        struct jffs2_full_dirent *fd;
        unsigned long curofs = 1;

        jffs2_dbg(1, "jffs2_readdir() for dir_i #%lu\n", inode->i_ino);

        if (!dir_emit_dots(file, ctx))
                return 0;

        mutex_lock(&f->sem);
        for (fd = f->dents; fd; fd = fd->next) {
                curofs++;
                /* First loop: curofs = 2; pos = 2 */
                if (curofs < ctx->pos) {
                        jffs2_dbg(2, "Skipping dirent: \"%s\", ino #%u, type %d, because curofs %ld < offset %ld\n",
                                  fd->name, fd->ino, fd->type, curofs, (unsigned long)ctx->pos);
                        continue;
                }
                if (!fd->ino) {
                        jffs2_dbg(2, "Skipping deletion dirent \"%s\"\n",
                                  fd->name);
                        ctx->pos++;
                        continue;
                }
                jffs2_dbg(2, "Dirent %ld: \"%s\", ino #%u, type %d\n",
                          (unsigned long)ctx->pos, fd->name, fd->ino, fd->type);
                if (!dir_emit(ctx, fd->name, strlen(fd->name), fd->ino, fd->type))
                        break;
                ctx->pos++;
        }
        mutex_unlock(&f->sem);
        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;
}