Exemplo n.º 1
0
/*
 * return to user-space the branch indices containing the file in question
 *
 * We use fd_set and therefore we are limited to the number of the branches
 * to FD_SETSIZE, which is currently 1024 - plenty for most people
 */
static int unionfs_ioctl_queryfile(struct file *file, struct dentry *parent,
				   unsigned int cmd, unsigned long arg)
{
	int err = 0;
	fd_set branchlist;
	int bstart = 0, bend = 0, bindex = 0;
	int orig_bstart, orig_bend;
	struct dentry *dentry, *lower_dentry;
	struct vfsmount *mnt;

	dentry = file->f_path.dentry;
	orig_bstart = dbstart(dentry);
	orig_bend = dbend(dentry);
	err = unionfs_partial_lookup(dentry, parent);
	if (err)
		goto out;
	bstart = dbstart(dentry);
	bend = dbend(dentry);

	FD_ZERO(&branchlist);

	for (bindex = bstart; bindex <= bend; bindex++) {
		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
		if (!lower_dentry)
			continue;
		if (likely(lower_dentry->d_inode))
			FD_SET(bindex, &branchlist);
		/* purge any lower objects after partial_lookup */
		if (bindex < orig_bstart || bindex > orig_bend) {
			dput(lower_dentry);
			unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
			iput(unionfs_lower_inode_idx(dentry->d_inode, bindex));
			unionfs_set_lower_inode_idx(dentry->d_inode, bindex,
						    NULL);
			mnt = unionfs_lower_mnt_idx(dentry, bindex);
			if (!mnt)
				continue;
			unionfs_mntput(dentry, bindex);
			unionfs_set_lower_mnt_idx(dentry, bindex, NULL);
		}
	}
	/* restore original dentry's offsets */
	dbstart(dentry) = orig_bstart;
	dbend(dentry) = orig_bend;
	ibstart(dentry->d_inode) = orig_bstart;
	ibend(dentry->d_inode) = orig_bend;

	err = copy_to_user((void __user *)arg, &branchlist, sizeof(fd_set));
	if (unlikely(err))
		err = -EFAULT;

out:
	return err < 0 ? err : bend;
}
Exemplo n.º 2
0
/*
 * This is a helper function for rename, used when rename ends up with hosed
 * over dentries and we need to revert.
 */
static int unionfs_refresh_lower_dentry(struct dentry *dentry,
					struct dentry *parent, int bindex)
{
	struct dentry *lower_dentry;
	struct dentry *lower_parent;
	int err = 0;

	verify_locked(dentry);

	lower_parent = unionfs_lower_dentry_idx(parent, bindex);

	BUG_ON(!S_ISDIR(lower_parent->d_inode->i_mode));

	lower_dentry = lookup_one_len(dentry->d_name.name, lower_parent,
				      dentry->d_name.len);
	if (IS_ERR(lower_dentry)) {
		err = PTR_ERR(lower_dentry);
		goto out;
	}

	dput(unionfs_lower_dentry_idx(dentry, bindex));
	iput(unionfs_lower_inode_idx(dentry->d_inode, bindex));
	unionfs_set_lower_inode_idx(dentry->d_inode, bindex, NULL);

	if (!lower_dentry->d_inode) {
		dput(lower_dentry);
		unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
	} else {
		unionfs_set_lower_dentry_idx(dentry, bindex, lower_dentry);
		unionfs_set_lower_inode_idx(dentry->d_inode, bindex,
					    igrab(lower_dentry->d_inode));
	}

out:
	return err;
}
Exemplo n.º 3
0
/*
 * Copy up a dentry to a file of specified name.
 *
 * @dir: used to pull the ->i_sb to access other branches
 * @dentry: the non-negative dentry whose lower_inode we should copy
 * @bstart: the branch of the lower_inode to copy from
 * @new_bindex: the branch to create the new file in
 * @name: the name of the file to create
 * @namelen: length of @name
 * @copyup_file: the "struct file" to return (optional)
 * @len: how many bytes to copy-up?
 */
int copyup_dentry(struct inode *dir, struct dentry *dentry, int bstart,
		  int new_bindex, const char *name, int namelen,
		  struct file **copyup_file, loff_t len)
{
	struct dentry *new_lower_dentry;
	struct dentry *old_lower_dentry = NULL;
	struct super_block *sb;
	int err = 0;
	int old_bindex;
	int old_bstart;
	int old_bend;
	struct dentry *new_lower_parent_dentry = NULL;
	mm_segment_t oldfs;
	char *symbuf = NULL;

	verify_locked(dentry);

	old_bindex = bstart;
	old_bstart = dbstart(dentry);
	old_bend = dbend(dentry);

	BUG_ON(new_bindex < 0);
	BUG_ON(new_bindex >= old_bindex);

	sb = dir->i_sb;

	err = is_robranch_super(sb, new_bindex);
	if (err)
		goto out;

	/* Create the directory structure above this dentry. */
	new_lower_dentry = create_parents(dir, dentry, name, new_bindex);
	if (IS_ERR(new_lower_dentry)) {
		err = PTR_ERR(new_lower_dentry);
		goto out;
	}

	old_lower_dentry = unionfs_lower_dentry_idx(dentry, old_bindex);
	/* we conditionally dput this old_lower_dentry at end of function */
	dget(old_lower_dentry);

	/* For symlinks, we must read the link before we lock the directory. */
	if (S_ISLNK(old_lower_dentry->d_inode->i_mode)) {

		symbuf = kmalloc(PATH_MAX, GFP_KERNEL);
		if (unlikely(!symbuf)) {
			__clear(dentry, old_lower_dentry,
				old_bstart, old_bend,
				new_lower_dentry, new_bindex);
			err = -ENOMEM;
			goto out_free;
		}

		oldfs = get_fs();
		set_fs(KERNEL_DS);
		err = old_lower_dentry->d_inode->i_op->readlink(
			old_lower_dentry,
			(char __user *)symbuf,
			PATH_MAX);
		set_fs(oldfs);
		if (err < 0) {
			__clear(dentry, old_lower_dentry,
				old_bstart, old_bend,
				new_lower_dentry, new_bindex);
			goto out_free;
		}
		symbuf[err] = '\0';
	}

	/* Now we lock the parent, and create the object in the new branch. */
	new_lower_parent_dentry = lock_parent(new_lower_dentry);

	/* create the new inode */
	err = __copyup_ndentry(old_lower_dentry, new_lower_dentry,
			       new_lower_parent_dentry, symbuf);

	if (err) {
		__clear(dentry, old_lower_dentry,
			old_bstart, old_bend,
			new_lower_dentry, new_bindex);
		goto out_unlock;
	}

	/* We actually copyup the file here. */
	if (S_ISREG(old_lower_dentry->d_inode->i_mode))
		err = __copyup_reg_data(dentry, new_lower_dentry, new_bindex,
					old_lower_dentry, old_bindex,
					copyup_file, len);
	if (err)
		goto out_unlink;

	/* Set permissions. */
	err = copyup_permissions(sb, old_lower_dentry, new_lower_dentry);
	if (err)
		goto out_unlink;

#ifdef CONFIG_UNION_FS_XATTR
	/* Selinux uses extended attributes for permissions. */
	err = copyup_xattrs(old_lower_dentry, new_lower_dentry);
	if (err)
		goto out_unlink;
#endif /* CONFIG_UNION_FS_XATTR */

	/* do not allow files getting deleted to be re-interposed */
	if (!d_deleted(dentry))
		unionfs_reinterpose(dentry);

	goto out_unlock;

out_unlink:
	/*
	 * copyup failed, because we possibly ran out of space or
	 * quota, or something else happened so let's unlink; we don't
	 * really care about the return value of vfs_unlink
	 */
	vfs_unlink(new_lower_parent_dentry->d_inode, new_lower_dentry);

	if (copyup_file) {
		/* need to close the file */

		fput(*copyup_file);
		branchput(sb, new_bindex);
	}

	/*
	 * TODO: should we reset the error to something like -EIO?
	 *
	 * If we don't reset, the user may get some nonsensical errors, but
	 * on the other hand, if we reset to EIO, we guarantee that the user
	 * will get a "confusing" error message.
	 */

out_unlock:
	unlock_dir(new_lower_parent_dentry);

out_free:
	/*
	 * If old_lower_dentry was not a file, then we need to dput it.  If
	 * it was a file, then it was already dput indirectly by other
	 * functions we call above which operate on regular files.
	 */
	if (old_lower_dentry && old_lower_dentry->d_inode &&
	    !S_ISREG(old_lower_dentry->d_inode->i_mode))
		dput(old_lower_dentry);
	kfree(symbuf);

	if (err) {
		/*
		 * if directory creation succeeded, but inode copyup failed,
		 * then purge new dentries.
		 */
		if (dbstart(dentry) < old_bstart &&
		    ibstart(dentry->d_inode) > dbstart(dentry))
			__clear(dentry, NULL, old_bstart, old_bend,
				unionfs_lower_dentry(dentry), dbstart(dentry));
		goto out;
	}
	if (!S_ISDIR(dentry->d_inode->i_mode)) {
		unionfs_postcopyup_release(dentry);
		if (!unionfs_lower_inode(dentry->d_inode)) {
			/*
			 * If we got here, then we copied up to an
			 * unlinked-open file, whose name is .unionfsXXXXX.
			 */
			struct inode *inode = new_lower_dentry->d_inode;
			atomic_inc(&inode->i_count);
			unionfs_set_lower_inode_idx(dentry->d_inode,
						    ibstart(dentry->d_inode),
						    inode);
		}
	}
	unionfs_postcopyup_setmnt(dentry);
	/* sync inode times from copied-up inode to our inode */
	unionfs_copy_attr_times(dentry->d_inode);
	unionfs_check_inode(dir);
	unionfs_check_dentry(dentry);
out:
	return err;
}
Exemplo n.º 4
0
/*
 * 1) Copyup the file
 * 2) Rename the file to '.unionfs<original inode#><counter>' - obviously
 * stolen from NFS's silly rename
 */
static int copyup_deleted_file(struct file *file, struct dentry *dentry,
			       struct dentry *parent, int bstart, int bindex)
{
	static unsigned int counter;
	const int i_inosize = sizeof(dentry->d_inode->i_ino) * 2;
	const int countersize = sizeof(counter) * 2;
	const int nlen = sizeof(".unionfs") + i_inosize + countersize - 1;
	char name[nlen + 1];
	int err;
	struct dentry *tmp_dentry = NULL;
	struct dentry *lower_dentry;
	struct dentry *lower_dir_dentry = NULL;

	lower_dentry = unionfs_lower_dentry_idx(dentry, bstart);

	sprintf(name, ".unionfs%*.*lx",
		i_inosize, i_inosize, lower_dentry->d_inode->i_ino);

	/*
	 * Loop, looking for an unused temp name to copyup to.
	 *
	 * It's somewhat silly that we look for a free temp tmp name in the
	 * source branch (bstart) instead of the dest branch (bindex), where
	 * the final name will be created.  We _will_ catch it if somehow
	 * the name exists in the dest branch, but it'd be nice to catch it
	 * sooner than later.
	 */
retry:
	tmp_dentry = NULL;
	do {
		char *suffix = name + nlen - countersize;

		dput(tmp_dentry);
		counter++;
		sprintf(suffix, "%*.*x", countersize, countersize, counter);

		pr_debug("unionfs: trying to rename %s to %s\n",
			 dentry->d_name.name, name);

		tmp_dentry = lookup_lck_len(name, lower_dentry->d_parent,
					    nlen);
		if (IS_ERR(tmp_dentry)) {
			err = PTR_ERR(tmp_dentry);
			goto out;
		}
	} while (tmp_dentry->d_inode != NULL);	/* need negative dentry */
	dput(tmp_dentry);

	err = copyup_named_file(parent->d_inode, file, name, bstart, bindex,
				i_size_read(file->f_path.dentry->d_inode));
	if (err) {
		if (unlikely(err == -EEXIST))
			goto retry;
		goto out;
	}

	/* bring it to the same state as an unlinked file */
	lower_dentry = unionfs_lower_dentry_idx(dentry, dbstart(dentry));
	if (!unionfs_lower_inode_idx(dentry->d_inode, bindex)) {
		atomic_inc(&lower_dentry->d_inode->i_count);
		unionfs_set_lower_inode_idx(dentry->d_inode, bindex,
					    lower_dentry->d_inode);
	}
	lower_dir_dentry = lock_parent(lower_dentry);
	err = vfs_unlink(lower_dir_dentry->d_inode, lower_dentry);
	unlock_dir(lower_dir_dentry);

out:
	if (!err)
		unionfs_check_dentry(dentry);
	return err;
}
Exemplo n.º 5
0
/*
 * The locking rules in unionfs_rename are complex.  We could use a simpler
 * superblock-level name-space lock for renames and copy-ups.
 */
int unionfs_rename(struct inode *old_dir, struct dentry *old_dentry,
		   struct inode *new_dir, struct dentry *new_dentry)
{
	int err = 0;
	struct dentry *wh_dentry;
	struct dentry *old_parent, *new_parent;
	int valid = true;

	unionfs_read_lock(old_dentry->d_sb, UNIONFS_SMUTEX_CHILD);
	old_parent = dget_parent(old_dentry);
	new_parent = dget_parent(new_dentry);
	/* un/lock parent dentries only if they differ from old/new_dentry */
	if (old_parent != old_dentry &&
	    old_parent != new_dentry)
		unionfs_lock_dentry(old_parent, UNIONFS_DMUTEX_REVAL_PARENT);
	if (new_parent != old_dentry &&
	    new_parent != new_dentry &&
	    new_parent != old_parent)
		unionfs_lock_dentry(new_parent, UNIONFS_DMUTEX_REVAL_CHILD);
	unionfs_double_lock_dentry(old_dentry, new_dentry);

	valid = __unionfs_d_revalidate(old_dentry, old_parent, false);
	if (!valid) {
		err = -ESTALE;
		goto out;
	}
	if (!d_deleted(new_dentry) && new_dentry->d_inode) {
		valid = __unionfs_d_revalidate(new_dentry, new_parent, false);
		if (!valid) {
			err = -ESTALE;
			goto out;
		}
	}

	if (!S_ISDIR(old_dentry->d_inode->i_mode))
		err = unionfs_partial_lookup(old_dentry, old_parent);
	else
		err = may_rename_dir(old_dentry, old_parent);

	if (err)
		goto out;

	err = unionfs_partial_lookup(new_dentry, new_parent);
	if (err)
		goto out;

	/*
	 * if new_dentry is already lower because of whiteout,
	 * simply override it even if the whited-out dir is not empty.
	 */
	wh_dentry = find_first_whiteout(new_dentry);
	if (!IS_ERR(wh_dentry)) {
		dput(wh_dentry);
	} else if (new_dentry->d_inode) {
		if (S_ISDIR(old_dentry->d_inode->i_mode) !=
		    S_ISDIR(new_dentry->d_inode->i_mode)) {
			err = S_ISDIR(old_dentry->d_inode->i_mode) ?
				-ENOTDIR : -EISDIR;
			goto out;
		}

		if (S_ISDIR(new_dentry->d_inode->i_mode)) {
			struct unionfs_dir_state *namelist = NULL;
			/* check if this unionfs directory is empty or not */
			err = check_empty(new_dentry, new_parent, &namelist);
			if (err)
				goto out;

			if (!is_robranch(new_dentry))
				err = delete_whiteouts(new_dentry,
						       dbstart(new_dentry),
						       namelist);

			free_rdstate(namelist);

			if (err)
				goto out;
		}
	}

	err = do_unionfs_rename(old_dir, old_dentry, old_parent,
				new_dir, new_dentry, new_parent);
	if (err)
		goto out;

	/*
	 * force re-lookup since the dir on ro branch is not renamed, and
	 * lower dentries still indicate the un-renamed ones.
	 */
	if (S_ISDIR(old_dentry->d_inode->i_mode))
		atomic_dec(&UNIONFS_D(old_dentry)->generation);
	else
		unionfs_postcopyup_release(old_dentry);
	if (new_dentry->d_inode && !S_ISDIR(new_dentry->d_inode->i_mode)) {
		unionfs_postcopyup_release(new_dentry);
		unionfs_postcopyup_setmnt(new_dentry);
		if (!unionfs_lower_inode(new_dentry->d_inode)) {
			/*
			 * If we get here, it means that no copyup was
			 * needed, and that a file by the old name already
			 * existing on the destination branch; that file got
			 * renamed earlier in this function, so all we need
			 * to do here is set the lower inode.
			 */
			struct inode *inode;
			inode = unionfs_lower_inode(old_dentry->d_inode);
			igrab(inode);
			unionfs_set_lower_inode_idx(new_dentry->d_inode,
						    dbstart(new_dentry),
						    inode);
		}
	}
	/* if all of this renaming succeeded, update our times */
	unionfs_copy_attr_times(old_dentry->d_inode);
	unionfs_copy_attr_times(new_dentry->d_inode);
	unionfs_check_inode(old_dir);
	unionfs_check_inode(new_dir);
	unionfs_check_dentry(old_dentry);
	unionfs_check_dentry(new_dentry);

out:
	if (err)		/* clear the new_dentry stuff created */
		d_drop(new_dentry);

	unionfs_double_unlock_dentry(old_dentry, new_dentry);
	if (new_parent != old_dentry &&
	    new_parent != new_dentry &&
	    new_parent != old_parent)
		unionfs_unlock_dentry(new_parent);
	if (old_parent != old_dentry &&
	    old_parent != new_dentry)
		unionfs_unlock_dentry(old_parent);
	dput(new_parent);
	dput(old_parent);
	unionfs_read_unlock(old_dentry->d_sb);

	return err;
}