Exemple #1
0
static int unionfs_create(struct inode *dir, struct dentry *dentry,
			  umode_t mode, bool want_excl)
{
	int err = 0;
	struct dentry *lower_dentry = NULL;
	struct dentry *lower_parent_dentry = NULL;
	struct dentry *parent;
	int valid = 0;

	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
	parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);

	valid = __unionfs_d_revalidate(dentry, parent, false, 0);
	if (unlikely(!valid)) {
		err = -ESTALE;	/* same as what real_lookup does */
		goto out;
	}

	lower_dentry = find_writeable_branch(dir, dentry);
	if (IS_ERR(lower_dentry)) {
		err = PTR_ERR(lower_dentry);
		goto out;
	}

	lower_parent_dentry = lock_parent(lower_dentry);
	if (IS_ERR(lower_parent_dentry)) {
		err = PTR_ERR(lower_parent_dentry);
		goto out_unlock;
	}

	err = vfs_create(lower_parent_dentry->d_inode, lower_dentry, mode,
			 want_excl);
	if (!err) {
		err = PTR_ERR(unionfs_interpose(dentry, dir->i_sb, 0));
		if (!err) {
			unionfs_copy_attr_times(dir);
			fsstack_copy_inode_size(dir,
						lower_parent_dentry->d_inode);
			/* update no. of links on parent directory */
			set_nlink(dir, unionfs_get_nlinks(dir));
		}
	}

out_unlock:
	unlock_dir(lower_parent_dentry);
out:
	if (!err) {
		unionfs_postcopyup_setmnt(dentry);
		unionfs_check_inode(dir);
		unionfs_check_dentry(dentry);
	}
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);
	return err;
}
Exemple #2
0
/*
 * unionfs_lookup is the only special function which takes a dentry, yet we
 * do NOT want to call __unionfs_d_revalidate_chain because by definition,
 * we don't have a valid dentry here yet.
 */
static struct dentry *unionfs_lookup(struct inode *dir,
				     struct dentry *dentry,
				     /* XXX: pass flags to lower? */
				     unsigned int flags_unused)
{
	struct dentry *ret, *parent;
	int err = 0;

	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
	parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);

	/*
	 * As long as we lock/dget the parent, then can skip validating the
	 * parent now; we may have to rebuild this dentry on the next
	 * ->d_revalidate, however.
	 */

	/* allocate dentry private data.  We free it in ->d_release */
	err = new_dentry_private_data(dentry, UNIONFS_DMUTEX_CHILD);
	if (unlikely(err)) {
		ret = ERR_PTR(err);
		goto out;
	}

	ret = unionfs_lookup_full(dentry, parent, INTERPOSE_LOOKUP);

	if (!IS_ERR(ret)) {
		if (ret)
			dentry = ret;
		/* lookup_full can return multiple positive dentries */
		if (dentry->d_inode && !S_ISDIR(dentry->d_inode->i_mode)) {
			BUG_ON(dbstart(dentry) < 0);
			unionfs_postcopyup_release(dentry);
		}
		unionfs_copy_attr_times(dentry->d_inode);
	}

	unionfs_check_inode(dir);
	if (!IS_ERR(ret))
		unionfs_check_dentry(dentry);
	unionfs_check_dentry(parent);
	unionfs_unlock_dentry(dentry); /* locked in new_dentry_private data */

out:
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);

	return ret;
}
Exemple #3
0
/*
 * A unionfs/fanout version of fsstack_copy_attr_all.  Uses a
 * unionfs_get_nlinks to properly calcluate the number of links to a file.
 * Also, copies the max() of all a/m/ctimes for all lower inodes (which is
 * important if the lower inode is a directory type)
 */
void unionfs_copy_attr_all(struct inode *dest,
			   const struct inode *src)
{
	dest->i_mode = src->i_mode;
	dest->i_uid = src->i_uid;
	dest->i_gid = src->i_gid;
	dest->i_rdev = src->i_rdev;

	unionfs_copy_attr_times(dest);

	dest->i_blkbits = src->i_blkbits;
	dest->i_flags = src->i_flags;

	/*
	 * Update the nlinks AFTER updating the above fields, because the
	 * get_links callback may depend on them.
	 */
	dest->i_nlink = unionfs_get_nlinks(dest);
}
Exemple #4
0
/*
 * Don't grab the superblock read-lock in unionfs_permission, which prevents
 * a deadlock with the branch-management "add branch" code (which grabbed
 * the write lock).  It is safe to not grab the read lock here, because even
 * with branch management taking place, there is no chance that
 * unionfs_permission, or anything it calls, will use stale branch
 * information.
 */
static int unionfs_permission(struct inode *inode, int mask)
{
	struct inode *lower_inode = NULL;
	int err = 0;
	int bindex, bstart, bend;
	int is_file;
	const int write_mask = (mask & MAY_WRITE) && !(mask & MAY_READ);
	struct inode *inode_grabbed;

	inode_grabbed = igrab(inode);
	is_file = !S_ISDIR(inode->i_mode);

	if (!UNIONFS_I(inode)->lower_inodes) {
		if (is_file)	/* dirs can be unlinked but chdir'ed to */
			err = -ESTALE;	/* force revalidate */
		goto out;
	}
	bstart = ibstart(inode);
	bend = ibend(inode);
	if (unlikely(bstart < 0 || bend < 0)) {
		/*
		 * With branch-management, we can get a stale inode here.
		 * If so, we return ESTALE back to link_path_walk, which
		 * would discard the dcache entry and re-lookup the
		 * dentry+inode.  This should be equivalent to issuing
		 * __unionfs_d_revalidate_chain on nd.dentry here.
		 */
		if (is_file)	/* dirs can be unlinked but chdir'ed to */
			err = -ESTALE;	/* force revalidate */
		goto out;
	}

	for (bindex = bstart; bindex <= bend; bindex++) {
		lower_inode = unionfs_lower_inode_idx(inode, bindex);
		if (!lower_inode)
			continue;

		/*
		 * check the condition for D-F-D underlying files/directories,
		 * we don't have to check for files, if we are checking for
		 * directories.
		 */
		if (!is_file && !S_ISDIR(lower_inode->i_mode))
			continue;

		/*
		 * We check basic permissions, but we ignore any conditions
		 * such as readonly file systems or branches marked as
		 * readonly, because those conditions should lead to a
		 * copyup taking place later on.  However, if user never had
		 * access to the file, then no copyup could ever take place.
		 */
		err = __inode_permission(lower_inode, mask);
		if (err && err != -EACCES && err != EPERM && bindex > 0) {
			umode_t mode = lower_inode->i_mode;
			if ((is_robranch_super(inode->i_sb, bindex) ||
			     __is_rdonly(lower_inode)) &&
			    (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
				err = 0;
			if (IS_COPYUP_ERR(err))
				err = 0;
		}

		/*
		 * NFS HACK: NFSv2/3 return EACCES on readonly-exported,
		 * locally readonly-mounted file systems, instead of EROFS
		 * like other file systems do.  So we have no choice here
		 * but to intercept this and ignore it for NFS branches
		 * marked readonly.  Specifically, we avoid using NFS's own
		 * "broken" ->permission method, and rely on
		 * generic_permission() to do basic checking for us.
		 */
		if (err && err == -EACCES &&
		    is_robranch_super(inode->i_sb, bindex) &&
		    lower_inode->i_sb->s_magic == NFS_SUPER_MAGIC)
			err = generic_permission(lower_inode, mask);

		/*
		 * The permissions are an intersection of the overall directory
		 * permissions, so we fail if one fails.
		 */
		if (err)
			goto out;

		/* only the leftmost file matters. */
		if (is_file || write_mask) {
			if (is_file && write_mask) {
				err = get_write_access(lower_inode);
				if (!err)
					put_write_access(lower_inode);
			}
			break;
		}
	}
	/* sync times which may have changed (asynchronously) below */
	unionfs_copy_attr_times(inode);

out:
	unionfs_check_inode(inode);
	iput(inode_grabbed);
	return err;
}
Exemple #5
0
static int unionfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
			 dev_t dev)
{
	int err = 0;
	struct dentry *lower_dentry = NULL;
	struct dentry *wh_dentry = NULL;
	struct dentry *lower_parent_dentry = NULL;
	struct dentry *parent;
	char *name = NULL;
	int valid = 0;

	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
	parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);

	valid = __unionfs_d_revalidate(dentry, parent, false, 0);
	if (unlikely(!valid)) {
		err = -ESTALE;
		goto out;
	}

	/*
	 * It's only a bug if this dentry was not negative and couldn't be
	 * revalidated (shouldn't happen).
	 */
	BUG_ON(!valid && dentry->d_inode);

	lower_dentry = find_writeable_branch(dir, dentry);
	if (IS_ERR(lower_dentry)) {
		err = PTR_ERR(lower_dentry);
		goto out;
	}

	lower_parent_dentry = lock_parent(lower_dentry);
	if (IS_ERR(lower_parent_dentry)) {
		err = PTR_ERR(lower_parent_dentry);
		goto out_unlock;
	}

	err = vfs_mknod(lower_parent_dentry->d_inode, lower_dentry, mode, dev);
	if (!err) {
		err = PTR_ERR(unionfs_interpose(dentry, dir->i_sb, 0));
		if (!err) {
			unionfs_copy_attr_times(dir);
			fsstack_copy_inode_size(dir,
						lower_parent_dentry->d_inode);
			/* update no. of links on parent directory */
			set_nlink(dir, unionfs_get_nlinks(dir));
		}
	}

out_unlock:
	unlock_dir(lower_parent_dentry);
out:
	dput(wh_dentry);
	kfree(name);

	if (!err) {
		unionfs_postcopyup_setmnt(dentry);
		unionfs_check_inode(dir);
		unionfs_check_dentry(dentry);
	}
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);
	return err;
}
Exemple #6
0
static int unionfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
{
	int err = 0;
	struct dentry *lower_dentry = NULL;
	struct dentry *lower_parent_dentry = NULL;
	struct dentry *parent;
	int bindex = 0, bstart;
	char *name = NULL;
	int valid;

	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
	parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);

	valid = __unionfs_d_revalidate(dentry, parent, false, 0);
	if (unlikely(!valid)) {
		err = -ESTALE;	/* same as what real_lookup does */
		goto out;
	}

	bstart = dbstart(dentry);

	lower_dentry = unionfs_lower_dentry(dentry);

	/* check for a whiteout in new dentry branch, and delete it */
	err = check_unlink_whiteout(dentry, lower_dentry, bstart);
	if (err > 0)	       /* whiteout found and removed successfully */
		err = 0;
	if (err) {
		/* exit if the error returned was NOT -EROFS */
		if (!IS_COPYUP_ERR(err))
			goto out;
		bstart--;
	}

	/* check if copyup's needed, and mkdir */
	for (bindex = bstart; bindex >= 0; bindex--) {
		int i;
		int bend = dbend(dentry);

		if (is_robranch_super(dentry->d_sb, bindex))
			continue;

		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
		if (!lower_dentry) {
			lower_dentry = create_parents(dir, dentry,
						      dentry->d_name.name,
						      bindex);
			if (!lower_dentry || IS_ERR(lower_dentry)) {
				printk(KERN_ERR "unionfs: lower dentry "
				       " NULL for bindex = %d\n", bindex);
				continue;
			}
		}

		lower_parent_dentry = lock_parent(lower_dentry);

		if (IS_ERR(lower_parent_dentry)) {
			err = PTR_ERR(lower_parent_dentry);
			goto out;
		}

		err = vfs_mkdir(lower_parent_dentry->d_inode, lower_dentry,
				mode);

		unlock_dir(lower_parent_dentry);

		/* did the mkdir succeed? */
		if (err)
			break;

		for (i = bindex + 1; i <= bend; i++) {
			/* XXX: use path_put_lowers? */
			if (unionfs_lower_dentry_idx(dentry, i)) {
				dput(unionfs_lower_dentry_idx(dentry, i));
				unionfs_set_lower_dentry_idx(dentry, i, NULL);
			}
		}
		dbend(dentry) = bindex;

		/*
		 * Only INTERPOSE_LOOKUP can return a value other than 0 on
		 * err.
		 */
		err = PTR_ERR(unionfs_interpose(dentry, dir->i_sb, 0));
		if (!err) {
			unionfs_copy_attr_times(dir);
			fsstack_copy_inode_size(dir,
						lower_parent_dentry->d_inode);

			/* update number of links on parent directory */
			set_nlink(dir, unionfs_get_nlinks(dir));
		}

		err = make_dir_opaque(dentry, dbstart(dentry));
		if (err) {
			printk(KERN_ERR "unionfs: mkdir: error creating "
			       ".wh.__dir_opaque: %d\n", err);
			goto out;
		}

		/* we are done! */
		break;
	}

out:
	if (!dentry->d_inode)
		d_drop(dentry);

	kfree(name);

	if (!err) {
		unionfs_copy_attr_times(dentry->d_inode);
		unionfs_postcopyup_setmnt(dentry);
	}
	unionfs_check_inode(dir);
	unionfs_check_dentry(dentry);
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);

	return err;
}
Exemple #7
0
static int unionfs_link(struct dentry *old_dentry, struct inode *dir,
			struct dentry *new_dentry)
{
	int err = 0;
	struct dentry *lower_old_dentry = NULL;
	struct dentry *lower_new_dentry = NULL;
	struct dentry *lower_dir_dentry = NULL;
	struct dentry *old_parent, *new_parent;
	char *name = NULL;
	bool valid;

	unionfs_read_lock(old_dentry->d_sb, UNIONFS_SMUTEX_CHILD);
	old_parent = dget_parent(old_dentry);
	new_parent = dget_parent(new_dentry);
	unionfs_double_lock_parents(old_parent, new_parent);
	unionfs_double_lock_dentry(old_dentry, new_dentry);

	valid = __unionfs_d_revalidate(old_dentry, old_parent, false, 0);
	if (unlikely(!valid)) {
		err = -ESTALE;
		goto out;
	}
	if (new_dentry->d_inode) {
		valid = __unionfs_d_revalidate(new_dentry, new_parent, false, 0);
		if (unlikely(!valid)) {
			err = -ESTALE;
			goto out;
		}
	}

	lower_new_dentry = unionfs_lower_dentry(new_dentry);

	/* check for a whiteout in new dentry branch, and delete it */
	err = check_unlink_whiteout(new_dentry, lower_new_dentry,
				    dbstart(new_dentry));
	if (err > 0) {	       /* whiteout found and removed successfully */
		lower_dir_dentry = dget_parent(lower_new_dentry);
		fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
		dput(lower_dir_dentry);
		set_nlink(dir, unionfs_get_nlinks(dir));
		err = 0;
	}
	if (err)
		goto out;

	/* check if parent hierachy is needed, then link in same branch */
	if (dbstart(old_dentry) != dbstart(new_dentry)) {
		lower_new_dentry = create_parents(dir, new_dentry,
						  new_dentry->d_name.name,
						  dbstart(old_dentry));
		err = PTR_ERR(lower_new_dentry);
		if (IS_COPYUP_ERR(err))
			goto docopyup;
		if (!lower_new_dentry || IS_ERR(lower_new_dentry))
			goto out;
	}
	lower_new_dentry = unionfs_lower_dentry(new_dentry);
	lower_old_dentry = unionfs_lower_dentry(old_dentry);

	BUG_ON(dbstart(old_dentry) != dbstart(new_dentry));
	lower_dir_dentry = lock_parent(lower_new_dentry);
	err = is_robranch(old_dentry);
	if (!err) {
		/* see Documentation/filesystems/unionfs/issues.txt */
		lockdep_off();
		err = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
			       lower_new_dentry);
		lockdep_on();
	}
	unlock_dir(lower_dir_dentry);

docopyup:
	if (IS_COPYUP_ERR(err)) {
		int old_bstart = dbstart(old_dentry);
		int bindex;

		for (bindex = old_bstart - 1; bindex >= 0; bindex--) {
			err = copyup_dentry(old_parent->d_inode,
					    old_dentry, old_bstart,
					    bindex, old_dentry->d_name.name,
					    old_dentry->d_name.len, NULL,
					    i_size_read(old_dentry->d_inode));
			if (err)
				continue;
			lower_new_dentry =
				create_parents(dir, new_dentry,
					       new_dentry->d_name.name,
					       bindex);
			lower_old_dentry = unionfs_lower_dentry(old_dentry);
			lower_dir_dentry = lock_parent(lower_new_dentry);
			/* see Documentation/filesystems/unionfs/issues.txt */
			lockdep_off();
			/* do vfs_link */
			err = vfs_link(lower_old_dentry,
				       lower_dir_dentry->d_inode,
				       lower_new_dentry);
			lockdep_on();
			unlock_dir(lower_dir_dentry);
			goto check_link;
		}
		goto out;
	}

check_link:
	if (err || !lower_new_dentry->d_inode)
		goto out;

	/* Its a hard link, so use the same inode */
	new_dentry->d_inode = igrab(old_dentry->d_inode);
	d_add(new_dentry, new_dentry->d_inode);
	unionfs_copy_attr_all(dir, lower_new_dentry->d_parent->d_inode);
	fsstack_copy_inode_size(dir, lower_new_dentry->d_parent->d_inode);

	/* propagate number of hard-links */
	set_nlink(old_dentry->d_inode,
		  unionfs_get_nlinks(old_dentry->d_inode));
	/* new dentry's ctime may have changed due to hard-link counts */
	unionfs_copy_attr_times(new_dentry->d_inode);

out:
	if (!new_dentry->d_inode)
		d_drop(new_dentry);

	kfree(name);
	if (!err)
		unionfs_postcopyup_setmnt(new_dentry);

	unionfs_check_inode(dir);
	unionfs_check_dentry(new_dentry);
	unionfs_check_dentry(old_dentry);

	unionfs_double_unlock_dentry(old_dentry, new_dentry);
	unionfs_double_unlock_parents(old_parent, new_parent);
	dput(new_parent);
	dput(old_parent);
	unionfs_read_unlock(old_dentry->d_sb);

	return err;
}
Exemple #8
0
/*
 * This function replicates the directory structure up-to given dentry
 * in the bindex branch.
 */
struct dentry *create_parents(struct inode *dir, struct dentry *dentry,
			      const char *name, int bindex)
{
	int err;
	struct dentry *child_dentry;
	struct dentry *parent_dentry;
	struct dentry *lower_parent_dentry = NULL;
	struct dentry *lower_dentry = NULL;
	const char *childname;
	unsigned int childnamelen;
	int nr_dentry;
	int count = 0;
	int old_bstart;
	int old_bend;
	struct dentry **path = NULL;
	struct super_block *sb;

	verify_locked(dentry);

	err = is_robranch_super(dir->i_sb, bindex);
	if (err) {
		lower_dentry = ERR_PTR(err);
		goto out;
	}

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

	lower_dentry = ERR_PTR(-ENOMEM);

	/* There is no sense allocating any less than the minimum. */
	nr_dentry = 1;
	path = kmalloc(nr_dentry * sizeof(struct dentry *), GFP_KERNEL);
	if (unlikely(!path))
		goto out;

	/* assume the negative dentry of unionfs as the parent dentry */
	parent_dentry = dentry;

	/*
	 * This loop finds the first parent that exists in the given branch.
	 * We start building the directory structure from there.  At the end
	 * of the loop, the following should hold:
	 *  - child_dentry is the first nonexistent child
	 *  - parent_dentry is the first existent parent
	 *  - path[0] is the = deepest child
	 *  - path[count] is the first child to create
	 */
	do {
		child_dentry = parent_dentry;

		/* find the parent directory dentry in unionfs */
		parent_dentry = dget_parent(child_dentry);

		/* find out the lower_parent_dentry in the given branch */
		lower_parent_dentry =
			unionfs_lower_dentry_idx(parent_dentry, bindex);

		/* grow path table */
		if (count == nr_dentry) {
			void *p;

			nr_dentry *= 2;
			p = krealloc(path, nr_dentry * sizeof(struct dentry *),
				     GFP_KERNEL);
			if (unlikely(!p)) {
				lower_dentry = ERR_PTR(-ENOMEM);
				goto out;
			}
			path = p;
		}

		/* store the child dentry */
		path[count++] = child_dentry;
	} while (!lower_parent_dentry);
	count--;

	sb = dentry->d_sb;

	/*
	 * This code goes between the begin/end labels and basically
	 * emulates a while(child_dentry != dentry), only cleaner and
	 * shorter than what would be a much longer while loop.
	 */
begin:
	/* get lower parent dir in the current branch */
	lower_parent_dentry = unionfs_lower_dentry_idx(parent_dentry, bindex);
	dput(parent_dentry);

	/* init the values to lookup */
	childname = child_dentry->d_name.name;
	childnamelen = child_dentry->d_name.len;

	if (child_dentry != dentry) {
		/* lookup child in the underlying file system */
		lower_dentry = lookup_one_len(childname, lower_parent_dentry,
					      childnamelen);
		if (IS_ERR(lower_dentry))
			goto out;
	} else {
		/*
		 * Is the name a whiteout of the child name ?  lookup the
		 * whiteout child in the underlying file system
		 */
		lower_dentry = lookup_one_len(name, lower_parent_dentry,
					      strlen(name));
		if (IS_ERR(lower_dentry))
			goto out;

		/* Replace the current dentry (if any) with the new one */
		dput(unionfs_lower_dentry_idx(dentry, bindex));
		unionfs_set_lower_dentry_idx(dentry, bindex,
					     lower_dentry);

		__cleanup_dentry(dentry, bindex, old_bstart, old_bend);
		goto out;
	}

	if (lower_dentry->d_inode) {
		/*
		 * since this already exists we dput to avoid
		 * multiple references on the same dentry
		 */
		dput(lower_dentry);
	} else {
		struct sioq_args args;

		/* it's a negative dentry, create a new dir */
		lower_parent_dentry = lock_parent(lower_dentry);

		args.mkdir.parent = lower_parent_dentry->d_inode;
		args.mkdir.dentry = lower_dentry;
		args.mkdir.mode = child_dentry->d_inode->i_mode;

		run_sioq(__unionfs_mkdir, &args);
		err = args.err;

		if (!err)
			err = copyup_permissions(dir->i_sb, child_dentry,
						 lower_dentry);
		unlock_dir(lower_parent_dentry);
		if (err) {
			dput(lower_dentry);
			lower_dentry = ERR_PTR(err);
			goto out;
		}

	}

	__set_inode(child_dentry, lower_dentry, bindex);
	__set_dentry(child_dentry, lower_dentry, bindex);
	/*
	 * update times of this dentry, but also the parent, because if
	 * we changed, the parent may have changed too.
	 */
	fsstack_copy_attr_times(parent_dentry->d_inode,
				lower_parent_dentry->d_inode);
	unionfs_copy_attr_times(child_dentry->d_inode);

	parent_dentry = child_dentry;
	child_dentry = path[--count];
	goto begin;
out:
	/* cleanup any leftover locks from the do/while loop above */
	if (IS_ERR(lower_dentry))
		while (count)
			dput(path[count--]);
	kfree(path);
	return lower_dentry;
}
Exemple #9
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;
}
Exemple #10
0
int unionfs_open(struct inode *inode, struct file *file)
{
	int err = 0;
	struct file *lower_file = NULL;
	struct dentry *dentry = file->f_path.dentry;
	struct dentry *parent;
	int bindex = 0, bstart = 0, bend = 0;
	int size;
	int valid = 0;

	unionfs_read_lock(inode->i_sb, UNIONFS_SMUTEX_PARENT);
	parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);

	/* don't open unhashed/deleted files */
	if (d_deleted(dentry)) {
		err = -ENOENT;
		goto out_nofree;
	}

	/* XXX: should I change 'false' below to the 'willwrite' flag? */
	valid = __unionfs_d_revalidate(dentry, parent, false);
	if (unlikely(!valid)) {
		err = -ESTALE;
		goto out_nofree;
	}

	file->private_data =
		kzalloc(sizeof(struct unionfs_file_info), GFP_KERNEL);
	if (unlikely(!UNIONFS_F(file))) {
		err = -ENOMEM;
		goto out_nofree;
	}
	fbstart(file) = -1;
	fbend(file) = -1;
	atomic_set(&UNIONFS_F(file)->generation,
		   atomic_read(&UNIONFS_I(inode)->generation));

	size = sizeof(struct file *) * sbmax(inode->i_sb);
	UNIONFS_F(file)->lower_files = kzalloc(size, GFP_KERNEL);
	if (unlikely(!UNIONFS_F(file)->lower_files)) {
		err = -ENOMEM;
		goto out;
	}
	size = sizeof(int) * sbmax(inode->i_sb);
	UNIONFS_F(file)->saved_branch_ids = kzalloc(size, GFP_KERNEL);
	if (unlikely(!UNIONFS_F(file)->saved_branch_ids)) {
		err = -ENOMEM;
		goto out;
	}

	bstart = fbstart(file) = dbstart(dentry);
	bend = fbend(file) = dbend(dentry);

	/*
	 * open all directories and make the unionfs file struct point to
	 * these lower file structs
	 */
	if (S_ISDIR(inode->i_mode))
		err = __open_dir(inode, file);	/* open a dir */
	else
		err = __open_file(inode, file, parent);	/* open a file */

	/* freeing the allocated resources, and fput the opened files */
	if (err) {
		for (bindex = bstart; bindex <= bend; bindex++) {
			lower_file = unionfs_lower_file_idx(file, bindex);
			if (!lower_file)
				continue;

			branchput(dentry->d_sb, bindex);
			/* fput calls dput for lower_dentry */
			fput(lower_file);
		}
	}

out:
	if (err) {
		kfree(UNIONFS_F(file)->lower_files);
		kfree(UNIONFS_F(file)->saved_branch_ids);
		kfree(UNIONFS_F(file));
	}
out_nofree:
	if (!err) {
		unionfs_postcopyup_setmnt(dentry);
		unionfs_copy_attr_times(inode);
		unionfs_check_file(file);
		unionfs_check_inode(inode);
	}
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(inode->i_sb);
	return err;
}
Exemple #11
0
static int unionfs_mmap(struct file *file, struct vm_area_struct *vma)
{
	int err = 0;
	bool willwrite;
	struct file *lower_file;
	struct dentry *dentry = file->f_path.dentry;
	struct dentry *parent;
	struct vm_operations_struct *saved_vm_ops = NULL;

	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
	parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);

	/* This might be deferred to mmap's writepage */
	willwrite = ((vma->vm_flags | VM_SHARED | VM_WRITE) == vma->vm_flags);
	err = unionfs_file_revalidate(file, parent, willwrite);
	if (unlikely(err))
		goto out;
	unionfs_check_file(file);

	/*
	 * File systems which do not implement ->writepage may use
	 * generic_file_readonly_mmap as their ->mmap op.  If you call
	 * generic_file_readonly_mmap with VM_WRITE, you'd get an -EINVAL.
	 * But we cannot call the lower ->mmap op, so we can't tell that
	 * writeable mappings won't work.  Therefore, our only choice is to
	 * check if the lower file system supports the ->writepage, and if
	 * not, return EINVAL (the same error that
	 * generic_file_readonly_mmap returns in that case).
	 */
	lower_file = unionfs_lower_file(file);
	if (willwrite && !lower_file->f_mapping->a_ops->writepage) {
		err = -EINVAL;
		printk(KERN_ERR "unionfs: branch %d file system does not "
		       "support writeable mmap\n", fbstart(file));
		goto out;
	}

	/*
	 * find and save lower vm_ops.
	 *
	 * XXX: the VFS should have a cleaner way of finding the lower vm_ops
	 */
	if (!UNIONFS_F(file)->lower_vm_ops) {
		err = lower_file->f_op->mmap(lower_file, vma);
		if (err) {
			printk(KERN_ERR "unionfs: lower mmap failed %d\n", err);
			goto out;
		}
		saved_vm_ops = vma->vm_ops;
		err = do_munmap(current->mm, vma->vm_start,
				vma->vm_end - vma->vm_start);
		if (err) {
			printk(KERN_ERR "unionfs: do_munmap failed %d\n", err);
			goto out;
		}
	}

	file->f_mapping->a_ops = &unionfs_dummy_aops;
	err = generic_file_mmap(file, vma);
	file->f_mapping->a_ops = &unionfs_aops;
	if (err) {
		printk(KERN_ERR "unionfs: generic_file_mmap failed %d\n", err);
		goto out;
	}
	vma->vm_ops = &unionfs_vm_ops;
	if (!UNIONFS_F(file)->lower_vm_ops)
		UNIONFS_F(file)->lower_vm_ops = saved_vm_ops;

out:
	if (!err) {
		/* copyup could cause parent dir times to change */
		unionfs_copy_attr_times(parent->d_inode);
		unionfs_check_file(file);
	}
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);
	return err;
}
Exemple #12
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;
}