コード例 #1
0
ファイル: super.c プロジェクト: BackupTheBerlios/dss-svn
static void unionfs_read_inode(struct inode *inode)
{
	static struct address_space_operations unionfs_empty_aops;

	print_entry_location();

	if (!itopd(inode)) {
		FISTBUG
		    ("No kernel memory when allocating inode private data!\n");
	}

	PASSERT(inode->i_sb);
	memset(itopd(inode), 0, sizeof(struct unionfs_inode_info));
	itopd(inode)->b_start = -1;
	itopd(inode)->b_end = -1;
	atomic_set(&itopd(inode)->uii_generation,
		   atomic_read(&stopd(inode->i_sb)->usi_generation));
	itopd(inode)->uii_rdlock = SPIN_LOCK_UNLOCKED;
	itopd(inode)->uii_rdcount = 1;
	itopd(inode)->uii_hashsize = -1;
	INIT_LIST_HEAD(&itopd(inode)->uii_readdircache);

	if (sbmax(inode->i_sb) > UNIONFS_INLINE_OBJECTS) {
		int size =
		    (sbmax(inode->i_sb) -
		     UNIONFS_INLINE_OBJECTS) * sizeof(struct inode *);
		itohi_ptr(inode) = KMALLOC(size, GFP_UNIONFS);
		if (!itohi_ptr(inode)) {
			FISTBUG
			    ("No kernel memory when allocating lower-pointer array!\n");
		}
		memset(itohi_ptr(inode), 0, size);
	}
	memset(itohi_inline(inode), 0,
	       UNIONFS_INLINE_OBJECTS * sizeof(struct inode *));

	inode->i_version++;
	inode->i_op = &unionfs_main_iops;
	inode->i_fop = &unionfs_main_fops;
	/* I don't think ->a_ops is ever allowed to be NULL */
	inode->i_mapping->a_ops = &unionfs_empty_aops;
	fist_dprint(7, "setting inode 0x%p a_ops to empty (0x%p)\n",
		    inode, inode->i_mapping->a_ops);

	print_exit_location();
}
コード例 #2
0
ファイル: branchman.c プロジェクト: BackupTheBerlios/dss-svn
int unionfs_ioctl_addbranch(struct inode *inode, unsigned int cmd,
			    unsigned long arg)
{
	int err;
	struct unionfs_addbranch_args *addargs = NULL;
	struct nameidata nd;
	char *path = NULL;
	int gen;
	int i;
	int count;

	int pobjects;

	struct vfsmount **new_hidden_mnt = NULL;
	struct inode **new_uii_inode = NULL;
	struct dentry **new_udi_dentry = NULL;
	struct super_block **new_usi_sb = NULL;
	int *new_branchperms = NULL;
	atomic_t *new_counts = NULL;

	print_entry_location();

	err = -ENOMEM;
	addargs = KMALLOC(sizeof(struct unionfs_addbranch_args), GFP_UNIONFS);
	if (!addargs)
		goto out;

	err = -EFAULT;
	if (copy_from_user
	    (addargs, (void *)arg, sizeof(struct unionfs_addbranch_args)))
		goto out;

	err = -EINVAL;
	if (addargs->ab_perms & ~(MAY_READ | MAY_WRITE))
		goto out;
	if (!(addargs->ab_perms & MAY_READ))
		goto out;

	err = -E2BIG;
	if (sbend(inode->i_sb) > FD_SETSIZE)
		goto out;

	err = -ENOMEM;
	if (!(path = getname(addargs->ab_path)))
		goto out;

	err = path_lookup(path, LOOKUP_FOLLOW, &nd);

	RECORD_PATH_LOOKUP(&nd);
	if (err)
		goto out;
	if ((err = check_branch(&nd))) {
		path_release(&nd);
		RECORD_PATH_RELEASE(&nd);
		goto out;
	}

	unionfs_write_lock(inode->i_sb);
	lock_dentry(inode->i_sb->s_root);

	err = -EINVAL;
	if (addargs->ab_branch < 0
	    || (addargs->ab_branch > (sbend(inode->i_sb) + 1)))
		goto out;

	if ((err = newputmap(inode->i_sb)))
		goto out;

	stopd(inode->i_sb)->b_end++;
	dtopd(inode->i_sb->s_root)->udi_bcount++;
	set_dbend(inode->i_sb->s_root, dbend(inode->i_sb->s_root) + 1);
	itopd(inode->i_sb->s_root->d_inode)->b_end++;

	atomic_inc(&stopd(inode->i_sb)->usi_generation);
	gen = atomic_read(&stopd(inode->i_sb)->usi_generation);

	pobjects = (sbend(inode->i_sb) + 1) - UNIONFS_INLINE_OBJECTS;
	if (pobjects > 0) {
		/* Reallocate the dynamic structures. */
		new_hidden_mnt =
		    KMALLOC(sizeof(struct vfsmount *) * pobjects, GFP_UNIONFS);
		new_udi_dentry =
		    KMALLOC(sizeof(struct dentry *) * pobjects, GFP_UNIONFS);
		new_uii_inode =
		    KMALLOC(sizeof(struct inode *) * pobjects, GFP_UNIONFS);
		new_usi_sb =
		    KMALLOC(sizeof(struct super_block *) * pobjects,
			    GFP_UNIONFS);
		new_counts = KMALLOC(sizeof(atomic_t) * pobjects, GFP_UNIONFS);
		new_branchperms = KMALLOC(sizeof(int) * pobjects, GFP_UNIONFS);
		if (!new_hidden_mnt || !new_udi_dentry || !new_uii_inode
		    || !new_counts || !new_usi_sb || !new_branchperms) {
			err = -ENOMEM;
			goto out;
		}
		memset(new_hidden_mnt, 0, sizeof(struct vfsmount *) * pobjects);
		memset(new_udi_dentry, 0, sizeof(struct dentry *) * pobjects);
		memset(new_uii_inode, 0, sizeof(struct inode *) * pobjects);
		memset(new_usi_sb, 0, sizeof(struct super_block *) * pobjects);
		memset(new_branchperms, 0, sizeof(int) * pobjects);
	}

	/* Copy the in-place values to our new structure. */
	for (i = UNIONFS_INLINE_OBJECTS; i < addargs->ab_branch; i++) {
		int j = i - UNIONFS_INLINE_OBJECTS;

		count = branch_count(inode->i_sb, i);
		atomic_set(&(new_counts[j]), count);

		new_branchperms[j] = branchperms(inode->i_sb, i);
		new_hidden_mnt[j] = stohiddenmnt_index(inode->i_sb, i);

		new_usi_sb[j] = stohs_index(inode->i_sb, i);
		new_udi_dentry[j] = dtohd_index(inode->i_sb->s_root, i);
		new_uii_inode[j] = itohi_index(inode->i_sb->s_root->d_inode, i);
	}

	/* Shift the ends to the right (only handle reallocated bits). */
	for (i = sbend(inode->i_sb) - 1; i >= (int)addargs->ab_branch; i--) {
		int j = i + 1;
		int perms;
		struct vfsmount *hm;
		struct super_block *hs;
		struct dentry *hd;
		struct inode *hi;
		int pmindex;

		count = branch_count(inode->i_sb, i);
		perms = branchperms(inode->i_sb, i);
		hm = stohiddenmnt_index(inode->i_sb, i);
		hs = stohs_index(inode->i_sb, i);
		hd = dtohd_index(inode->i_sb->s_root, i);
		hi = itohi_index(inode->i_sb->s_root->d_inode, i);

		/* Update the newest putmap, so it is correct for later. */
		pmindex = stopd(inode->i_sb)->usi_lastputmap;
		pmindex -= stopd(inode->i_sb)->usi_firstputmap;
		stopd(inode->i_sb)->usi_putmaps[pmindex]->map[i] = j;

		if (j >= UNIONFS_INLINE_OBJECTS) {
			j -= UNIONFS_INLINE_OBJECTS;
			atomic_set(&(new_counts[j]), count);
			new_branchperms[j] = perms;
			new_hidden_mnt[j] = hm;
			new_usi_sb[j] = hs;
			new_udi_dentry[j] = hd;
			new_uii_inode[j] = hi;
		} else {
			set_branch_count(inode->i_sb, j, count);
			set_branchperms(inode->i_sb, j, perms);
			set_stohiddenmnt_index(inode->i_sb, j, hm);
			set_stohs_index(inode->i_sb, j, hs);
			set_dtohd_index(inode->i_sb->s_root, j, hd);
			set_itohi_index(inode->i_sb->s_root->d_inode, j, hi);
		}
	}

	/* Now we can free the old ones. */
	KFREE(dtopd(inode->i_sb->s_root)->udi_dentry_p);
	KFREE(itopd(inode->i_sb->s_root->d_inode)->uii_inode_p);
	KFREE(stopd(inode->i_sb)->usi_hidden_mnt_p);
	KFREE(stopd(inode->i_sb)->usi_sb_p);
	KFREE(stopd(inode->i_sb)->usi_sbcount_p);
	KFREE(stopd(inode->i_sb)->usi_branchperms_p);

	/* Update the real pointers. */
	dtohd_ptr(inode->i_sb->s_root) = new_udi_dentry;
	itohi_ptr(inode->i_sb->s_root->d_inode) = new_uii_inode;
	stohiddenmnt_ptr(inode->i_sb) = new_hidden_mnt;
	stohs_ptr(inode->i_sb) = new_usi_sb;
	stopd(inode->i_sb)->usi_sbcount_p = new_counts;
	stopd(inode->i_sb)->usi_branchperms_p = new_branchperms;

	/* Re-NULL the new ones so we don't try to free them. */
	new_hidden_mnt = NULL;
	new_udi_dentry = NULL;
	new_usi_sb = NULL;
	new_uii_inode = NULL;
	new_counts = NULL;
	new_branchperms = NULL;

	/* Put the new dentry information into it's slot. */
	set_dtohd_index(inode->i_sb->s_root, addargs->ab_branch, nd.dentry);
	set_itohi_index(inode->i_sb->s_root->d_inode, addargs->ab_branch,
			igrab(nd.dentry->d_inode));
	set_branchperms(inode->i_sb, addargs->ab_branch, addargs->ab_perms);
	set_branch_count(inode->i_sb, addargs->ab_branch, 0);
	set_stohiddenmnt_index(inode->i_sb, addargs->ab_branch, nd.mnt);
	set_stohs_index(inode->i_sb, addargs->ab_branch, nd.dentry->d_sb);

	atomic_set(&dtopd(inode->i_sb->s_root)->udi_generation, gen);
	atomic_set(&itopd(inode->i_sb->s_root->d_inode)->uii_generation, gen);

	fixputmaps(inode->i_sb);

      out:
	unlock_dentry(inode->i_sb->s_root);
	unionfs_write_unlock(inode->i_sb);

	KFREE(new_hidden_mnt);
	KFREE(new_udi_dentry);
	KFREE(new_uii_inode);
	KFREE(new_usi_sb);
	KFREE(new_counts);
	KFREE(new_branchperms);
	KFREE(addargs);
	if (path)
		putname(path);

	print_exit_status(err);

	return err;
}
コード例 #3
0
int unionfs_ioctl_addbranch(struct inode *inode, unsigned int cmd,
			    unsigned long arg)
{
	int err;
	struct unionfs_addbranch_args *addargs = NULL;
	struct nameidata nd;
	char *path = NULL;
	int gen;
	int i;

	int pobjects;

	struct unionfs_usi_data *new_data = NULL;
	struct dentry **new_udi_dentry = NULL;
	struct inode **new_uii_inode = NULL;

	struct dentry *root = NULL;
	struct dentry *hidden_root = NULL;

	print_entry_location();

	err = -ENOMEM;
	addargs = KMALLOC(sizeof(struct unionfs_addbranch_args), GFP_KERNEL);
	if (!addargs)
		goto out;

	err = -EFAULT;
	if (copy_from_user
	    (addargs, (const void __user *)arg,
	     sizeof(struct unionfs_addbranch_args)))
		goto out;

	err = -EINVAL;
	if (addargs->ab_perms & ~(MAY_READ | MAY_WRITE | MAY_NFSRO))
		goto out;
	if (!(addargs->ab_perms & MAY_READ))
		goto out;

	err = -E2BIG;
	if (sbend(inode->i_sb) > FD_SETSIZE)
		goto out;

	err = -ENOMEM;
	if (!(path = getname((const char __user *)addargs->ab_path)))
		goto out;

	err = path_lookup(path, LOOKUP_FOLLOW, &nd);

	RECORD_PATH_LOOKUP(&nd);
	if (err)
		goto out;
	if ((err = check_branch(&nd))) {
		path_release(&nd);
		RECORD_PATH_RELEASE(&nd);
		goto out;
	}

	unionfs_write_lock(inode->i_sb);
	lock_dentry(inode->i_sb->s_root);

	root = inode->i_sb->s_root;
	for (i = dbstart(inode->i_sb->s_root); i <= dbend(inode->i_sb->s_root);
	     i++) {
		hidden_root = dtohd_index(root, i);
		if (is_branch_overlap(hidden_root, nd.dentry)) {
			err = -EINVAL;
			goto out;
		}
	}

	err = -EINVAL;
	if (addargs->ab_branch < 0
	    || (addargs->ab_branch > (sbend(inode->i_sb) + 1)))
		goto out;

	if ((err = newputmap(inode->i_sb)))
		goto out;

	stopd(inode->i_sb)->b_end++;
	dtopd(inode->i_sb->s_root)->udi_bcount++;
	set_dbend(inode->i_sb->s_root, dbend(inode->i_sb->s_root) + 1);
	itopd(inode->i_sb->s_root->d_inode)->b_end++;

	atomic_inc(&stopd(inode->i_sb)->usi_generation);
	gen = atomic_read(&stopd(inode->i_sb)->usi_generation);

	pobjects = sbend(inode->i_sb) + 1;

	/* Reallocate the dynamic structures. */
	new_data = alloc_new_data(pobjects);
	new_udi_dentry = alloc_new_dentries(pobjects);
	new_uii_inode = KZALLOC(sizeof(struct inode *) * pobjects, GFP_KERNEL);

	if (!new_udi_dentry || !new_uii_inode || !new_data) {
		err = -ENOMEM;
		goto out;
	}

	/* Copy the in-place values to our new structure. */
	for (i = 0; i < addargs->ab_branch; i++) {
		atomic_set(&(new_data[i].sbcount),
			   branch_count(inode->i_sb, i));

		new_data[i].branchperms = branchperms(inode->i_sb, i);
		new_data[i].hidden_mnt = stohiddenmnt_index(inode->i_sb, i);
		new_data[i].sb = stohs_index(inode->i_sb, i);

		new_udi_dentry[i] = dtohd_index(inode->i_sb->s_root, i);
		new_uii_inode[i] = itohi_index(inode->i_sb->s_root->d_inode, i);
	}

	/* Shift the ends to the right (only handle reallocated bits). */
	for (i = sbend(inode->i_sb) - 1; i >= (int)addargs->ab_branch; i--) {
		int j = i + 1;
		int pmindex;

		atomic_set(&new_data[j].sbcount, branch_count(inode->i_sb, i));

		new_data[j].branchperms = branchperms(inode->i_sb, i);
		new_data[j].hidden_mnt = stohiddenmnt_index(inode->i_sb, i);
		new_data[j].sb = stohs_index(inode->i_sb, i);
		new_udi_dentry[j] = dtohd_index(inode->i_sb->s_root, i);
		new_uii_inode[j] = itohi_index(inode->i_sb->s_root->d_inode, i);

		/* Update the newest putmap, so it is correct for later. */
		pmindex = stopd(inode->i_sb)->usi_lastputmap;
		pmindex -= stopd(inode->i_sb)->usi_firstputmap;
		stopd(inode->i_sb)->usi_putmaps[pmindex]->map[i] = j;

	}

	/* Now we can free the old ones. */
	KFREE(dtopd(inode->i_sb->s_root)->udi_dentry);
	KFREE(itopd(inode->i_sb->s_root->d_inode)->uii_inode);
	KFREE(stopd(inode->i_sb)->usi_data);

	/* Update the real pointers. */
	dtohd_ptr(inode->i_sb->s_root) = new_udi_dentry;
	itohi_ptr(inode->i_sb->s_root->d_inode) = new_uii_inode;
	stopd(inode->i_sb)->usi_data = new_data;

	/* Re-NULL the new ones so we don't try to free them. */
	new_data = NULL;
	new_udi_dentry = NULL;
	new_uii_inode = NULL;

	/* Put the new dentry information into it's slot. */
	set_dtohd_index(inode->i_sb->s_root, addargs->ab_branch, nd.dentry);
	set_itohi_index(inode->i_sb->s_root->d_inode, addargs->ab_branch,
			IGRAB(nd.dentry->d_inode));
	set_branchperms(inode->i_sb, addargs->ab_branch, addargs->ab_perms);
	set_branch_count(inode->i_sb, addargs->ab_branch, 0);
	set_stohiddenmnt_index(inode->i_sb, addargs->ab_branch, nd.mnt);
	set_stohs_index(inode->i_sb, addargs->ab_branch, nd.dentry->d_sb);

	atomic_set(&dtopd(inode->i_sb->s_root)->udi_generation, gen);
	atomic_set(&itopd(inode->i_sb->s_root->d_inode)->uii_generation, gen);

	fixputmaps(inode->i_sb);

      out:
	unlock_dentry(inode->i_sb->s_root);
	unionfs_write_unlock(inode->i_sb);

	KFREE(new_udi_dentry);
	KFREE(new_uii_inode);
	KFREE(new_data);
	KFREE(addargs);
	if (path)
		putname(path);

	print_exit_status(err);

	return err;
}
コード例 #4
0
/*
 * THIS IS A BOOLEAN FUNCTION: returns 1 if valid, 0 otherwise.
 */
int unionfs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
{
	int valid = 1;		/* default is valid (1); invalid is 0. */
	struct dentry *hidden_dentry;
	int bindex, bstart, bend;
	int sbgen, dgen;
	int positive = 0;
	int locked = 0;
	int restart = 0;
	int interpose_flag;

	print_util_entry_location();

      restart:
	verify_locked(dentry);

	/* if the dentry is unhashed, do NOT revalidate */
	if (d_deleted(dentry)) {
		fist_dprint(6, "unhashed dentry being revalidated: %*s\n",
			    dentry->d_name.len, dentry->d_name.name);
		goto out;
	}

	BUG_ON(dbstart(dentry) == -1);
	if (dentry->d_inode)
		positive = 1;
	dgen = atomic_read(&dtopd(dentry)->udi_generation);
	sbgen = atomic_read(&stopd(dentry->d_sb)->usi_generation);
	/* If we are working on an unconnected dentry, then there is no
	 * revalidation to be done, because this file does not exist within the
	 * namespace, and Unionfs operates on the namespace, not data.
	 */
	if (sbgen != dgen) {
		struct dentry *result;
		int pdgen;

		unionfs_read_lock(dentry->d_sb);
		locked = 1;

		/* The root entry should always be valid */
		BUG_ON(IS_ROOT(dentry));

		/* We can't work correctly if our parent isn't valid. */
		pdgen = atomic_read(&dtopd(dentry->d_parent)->udi_generation);
		if (!restart && (pdgen != sbgen)) {
			unionfs_read_unlock(dentry->d_sb);
			locked = 0;
			/* We must be locked before our parent. */
			if (!
			    (dentry->d_parent->d_op->
			     d_revalidate(dentry->d_parent, nd))) {
				valid = 0;
				goto out;
			}
			restart = 1;
			goto restart;
		}
		BUG_ON(pdgen != sbgen);

		/* Free the pointers for our inodes and this dentry. */
		bstart = dbstart(dentry);
		bend = dbend(dentry);
		if (bstart >= 0) {
			struct dentry *hidden_dentry;
			for (bindex = bstart; bindex <= bend; bindex++) {
				hidden_dentry =
				    dtohd_index_nocheck(dentry, bindex);
				if (!hidden_dentry)
					continue;
				DPUT(hidden_dentry);
			}
		}
		set_dbstart(dentry, -1);
		set_dbend(dentry, -1);

		interpose_flag = INTERPOSE_REVAL_NEG;
		if (positive) {
			interpose_flag = INTERPOSE_REVAL;
			down(&dentry->d_inode->i_sem);
			bstart = ibstart(dentry->d_inode);
			bend = ibend(dentry->d_inode);
			if (bstart >= 0) {
				struct inode *hidden_inode;
				for (bindex = bstart; bindex <= bend; bindex++) {
					hidden_inode =
					    itohi_index(dentry->d_inode,
							bindex);
					if (!hidden_inode)
						continue;
					IPUT(hidden_inode);
				}
			}
			KFREE(itohi_ptr(dentry->d_inode));
			itohi_ptr(dentry->d_inode) = NULL;
			ibstart(dentry->d_inode) = -1;
			ibend(dentry->d_inode) = -1;
			up(&dentry->d_inode->i_sem);
		}

		result = unionfs_lookup_backend(dentry, interpose_flag);
		if (result) {
			if (IS_ERR(result)) {
				valid = 0;
				goto out;
			}
			/* current unionfs_lookup_backend() doesn't return
			   a valid dentry */
			DPUT(dentry);
			dentry = result;
		}

		if (positive && itopd(dentry->d_inode)->uii_stale) {
			make_stale_inode(dentry->d_inode);
			d_drop(dentry);
			valid = 0;
			goto out;
		}
		goto out;
	}

	/* The revalidation must occur across all branches */
	bstart = dbstart(dentry);
	bend = dbend(dentry);
	BUG_ON(bstart == -1);
	for (bindex = bstart; bindex <= bend; bindex++) {
		hidden_dentry = dtohd_index(dentry, bindex);
		if (!hidden_dentry || !hidden_dentry->d_op
		    || !hidden_dentry->d_op->d_revalidate)
			continue;

		if (!hidden_dentry->d_op->d_revalidate(hidden_dentry, nd))
			valid = 0;
	}

	if (!dentry->d_inode)
		valid = 0;
	if (valid)
		fist_copy_attr_all(dentry->d_inode, itohi(dentry->d_inode));

      out:
	if (locked)
		unionfs_read_unlock(dentry->d_sb);
	fist_print_dentry("revalidate out", dentry);
	print_util_exit_status(valid);
	return valid;
}
コード例 #5
0
/* sb we pass is unionfs's super_block */
int unionfs_interpose(struct dentry *dentry, struct super_block *sb, int flag)
{
	struct inode *hidden_inode;
	struct dentry *hidden_dentry;
	int err = 0;
	struct inode *inode;
	int is_negative_dentry = 1;
	int bindex, bstart, bend;

	print_entry("flag = %d", flag);

	verify_locked(dentry);

	fist_print_dentry("In unionfs_interpose", dentry);

	bstart = dbstart(dentry);
	bend = dbend(dentry);

	/* Make sure that we didn't get a negative dentry. */
	for (bindex = bstart; bindex <= bend; bindex++) {
		if (dtohd_index(dentry, bindex) &&
		    dtohd_index(dentry, bindex)->d_inode) {
			is_negative_dentry = 0;
			break;
		}
	}
	BUG_ON(is_negative_dentry);

	/* We allocate our new inode below, by calling iget.
	 * iget will call our read_inode which will initialize some
	 * of the new inode's fields
	 */

	/* On revalidate we've already got our own inode and just need
	 * to fix it up. */
	if (flag == INTERPOSE_REVAL) {
		inode = dentry->d_inode;
		itopd(inode)->b_start = -1;
		itopd(inode)->b_end = -1;
		atomic_set(&itopd(inode)->uii_generation,
			   atomic_read(&stopd(sb)->usi_generation));

		itohi_ptr(inode) =
		    KZALLOC(sbmax(sb) * sizeof(struct inode *), GFP_KERNEL);
		if (!itohi_ptr(inode)) {
			err = -ENOMEM;
			goto out;
		}
	} else {
		ino_t ino;
		/* get unique inode number for unionfs */
#ifdef UNIONFS_IMAP
		if (stopd(sb)->usi_persistent) {
			err = read_uin(sb, bindex,
				       dtohd_index(dentry,
						   bindex)->d_inode->i_ino,
				       O_CREAT, &ino);
			if (err)
				goto out;
		} else
#endif
			ino = iunique(sb, UNIONFS_ROOT_INO);

		inode = IGET(sb, ino);
		if (!inode) {
			err = -EACCES;	/* should be impossible??? */
			goto out;
		}
	}

	down(&inode->i_sem);
	if (atomic_read(&inode->i_count) > 1)
		goto skip;

	for (bindex = bstart; bindex <= bend; bindex++) {
		hidden_dentry = dtohd_index(dentry, bindex);
		if (!hidden_dentry) {
			set_itohi_index(inode, bindex, NULL);
			continue;
		}
		/* Initialize the hidden inode to the new hidden inode. */
		if (!hidden_dentry->d_inode)
			continue;
		set_itohi_index(inode, bindex, IGRAB(hidden_dentry->d_inode));
	}

	ibstart(inode) = dbstart(dentry);
	ibend(inode) = dbend(dentry);

	/* Use attributes from the first branch. */
	hidden_inode = itohi(inode);

	/* Use different set of inode ops for symlinks & directories */
	if (S_ISLNK(hidden_inode->i_mode))
		inode->i_op = &unionfs_symlink_iops;
	else if (S_ISDIR(hidden_inode->i_mode))
		inode->i_op = &unionfs_dir_iops;

	/* Use different set of file ops for directories */
	if (S_ISDIR(hidden_inode->i_mode))
		inode->i_fop = &unionfs_dir_fops;

	/* properly initialize special inodes */
	if (S_ISBLK(hidden_inode->i_mode) || S_ISCHR(hidden_inode->i_mode) ||
	    S_ISFIFO(hidden_inode->i_mode) || S_ISSOCK(hidden_inode->i_mode))
		init_special_inode(inode, hidden_inode->i_mode,
				   hidden_inode->i_rdev);

	/* Fix our inode's address operations to that of the lower inode (Unionfs is FiST-Lite) */
	if (inode->i_mapping->a_ops != hidden_inode->i_mapping->a_ops) {
		fist_dprint(7, "fixing inode 0x%p a_ops (0x%p -> 0x%p)\n",
			    inode, inode->i_mapping->a_ops,
			    hidden_inode->i_mapping->a_ops);
		inode->i_mapping->a_ops = hidden_inode->i_mapping->a_ops;
	}

	/* all well, copy inode attributes */
	fist_copy_attr_all(inode, hidden_inode);

      skip:
	/* only (our) lookup wants to do a d_add */
	switch (flag) {
	case INTERPOSE_DEFAULT:
	case INTERPOSE_REVAL_NEG:
		d_instantiate(dentry, inode);
		break;
	case INTERPOSE_LOOKUP:
		err = PTR_ERR(d_splice_alias(inode, dentry));
		break;
	case INTERPOSE_REVAL:
		/* Do nothing. */
		break;
	default:
		printk(KERN_ERR "Invalid interpose flag passed!");
		BUG();
	}

	fist_print_dentry("Leaving unionfs_interpose", dentry);
	fist_print_inode("Leaving unionfs_interpose", inode);
	up(&inode->i_sem);

      out:
	print_exit_status(err);
	return err;
}