Esempio n. 1
0
/*
 * BKL held by caller.
 * dentry->d_inode->i_mutex locked
 */
ssize_t unionfs_listxattr(struct dentry *dentry, char *list, size_t size)
{
	struct dentry *lower_dentry = NULL;
	struct dentry *parent;
	int err = -EOPNOTSUPP;
	char *encoded_list = NULL;
	bool 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);
	if (unlikely(!valid)) {
		err = -ESTALE;
		goto out;
	}

	lower_dentry = unionfs_lower_dentry(dentry);

	encoded_list = list;
	err = vfs_listxattr(lower_dentry, encoded_list, size);

out:
	unionfs_check_dentry(dentry);
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);
	return err;
}
Esempio n. 2
0
static ssize_t unionfs_write(struct file *file, const char __user *buf,
			     size_t count, loff_t *ppos)
{
	int err = 0;
	struct file *lower_file;
	struct dentry *dentry = file->f_path.dentry;
	struct dentry *parent;

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

	err = unionfs_file_revalidate(file, parent, true);
	if (unlikely(err))
		goto out;

	lower_file = unionfs_lower_file(file);
	err = vfs_write(lower_file, buf, count, ppos);
	/* update our inode times+sizes upon a successful lower write */
	if (err >= 0) {
		fsstack_copy_inode_size(dentry->d_inode,
					lower_file->f_path.dentry->d_inode);
		fsstack_copy_attr_times(dentry->d_inode,
					lower_file->f_path.dentry->d_inode);
		UNIONFS_F(file)->wrote_to_file = true; /* for delayed copyup */
		unionfs_check_file(file);
	}

out:
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);
	return err;
}
Esempio n. 3
0
/*
 * BKL held by caller.
 * dentry->d_inode->i_mutex locked
 */
int unionfs_setxattr(struct dentry *dentry, const char *name,
		     const void *value, size_t size, int flags)
{
	struct dentry *lower_dentry = NULL;
	struct dentry *parent;
	int err = -EOPNOTSUPP;
	bool 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);
	if (unlikely(!valid)) {
		err = -ESTALE;
		goto out;
	}

	lower_dentry = unionfs_lower_dentry(dentry);

	err = vfs_setxattr(lower_dentry, (char *) name, (void *) value,
			   size, flags);

out:
	unionfs_check_dentry(dentry);
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);
	return err;
}
Esempio n. 4
0
static int unionfs_readlink(struct dentry *dentry, char __user *buf,
			    int bufsiz)
{
	int err;
	struct dentry *parent;

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

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

	err = __unionfs_readlink(dentry, buf, bufsiz);

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

	return err;
}
Esempio n. 5
0
static ssize_t unionfs_splice_write(struct pipe_inode_info *pipe,
				    struct file *file, loff_t *ppos,
				    size_t len, unsigned int flags)
{
	ssize_t err = 0;
	struct file *lower_file;
	struct dentry *dentry = file->f_path.dentry;
	struct dentry *parent;

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

	err = unionfs_file_revalidate(file, parent, true);
	if (unlikely(err))
		goto out;

	lower_file = unionfs_lower_file(file);
	err = vfs_splice_from(pipe, lower_file, ppos, len, flags);
	/* update our inode times+sizes upon a successful lower write */
	if (err >= 0) {
		fsstack_copy_inode_size(dentry->d_inode,
					lower_file->f_path.dentry->d_inode);
		fsstack_copy_attr_times(dentry->d_inode,
					lower_file->f_path.dentry->d_inode);
		unionfs_check_file(file);
	}

out:
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);
	return err;
}
Esempio n. 6
0
static ssize_t unionfs_read(struct file *file, char __user *buf,
			    size_t count, loff_t *ppos)
{
	int err;
	struct file *lower_file;
	struct dentry *dentry = file->f_path.dentry;
	struct dentry *parent;

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

	err = unionfs_file_revalidate(file, parent, false);
	if (unlikely(err))
		goto out;

	lower_file = unionfs_lower_file(file);
	err = vfs_read(lower_file, buf, count, ppos);
	/* update our inode atime upon a successful lower read */
	if (err >= 0) {
		fsstack_copy_attr_atime(dentry->d_inode,
					lower_file->f_path.dentry->d_inode);
		unionfs_check_file(file);
	}

out:
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);
	return err;
}
Esempio n. 7
0
/* this @nd *IS* still used */
static void unionfs_put_link(struct dentry *dentry, struct nameidata *nd,
			     void *cookie)
{
	struct dentry *parent;
	char *buf;

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

	if (unlikely(!__unionfs_d_revalidate(dentry, parent, false)))
		printk(KERN_ERR
		       "unionfs: put_link failed to revalidate dentry\n");

	unionfs_check_dentry(dentry);
#if 0
	/* XXX: can't run this check b/c this fxn can receive a poisoned 'nd' PTR */
	unionfs_check_nd(nd);
#endif
	buf = nd_get_link(nd);
	if (!IS_ERR(buf))
		kfree(buf);
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);
}
Esempio n. 8
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;
}
Esempio n. 9
0
int unionfs_fsync(struct file *file, struct dentry *dentry, int datasync)
{
	int bindex, bstart, bend;
	struct file *lower_file;
	struct dentry *lower_dentry;
	struct dentry *parent;
	struct inode *lower_inode, *inode;
	int err = -EINVAL;

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

	err = unionfs_file_revalidate(file, parent, true);
	if (unlikely(err))
		goto out;
	unionfs_check_file(file);

	bstart = fbstart(file);
	bend = fbend(file);
	if (bstart < 0 || bend < 0)
		goto out;

	inode = dentry->d_inode;
	if (unlikely(!inode)) {
		printk(KERN_ERR
		       "unionfs: null lower inode in unionfs_fsync\n");
		goto out;
	}
	for (bindex = bstart; bindex <= bend; bindex++) {
		lower_inode = unionfs_lower_inode_idx(inode, bindex);
		if (!lower_inode || !lower_inode->i_fop->fsync)
			continue;
		lower_file = unionfs_lower_file_idx(file, bindex);
		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
		mutex_lock(&lower_inode->i_mutex);
		err = lower_inode->i_fop->fsync(lower_file,
						lower_dentry,
						datasync);
		if (!err && bindex == bstart)
			fsstack_copy_attr_times(inode, lower_inode);
		mutex_unlock(&lower_inode->i_mutex);
		if (err)
			goto out;
	}

out:
	if (!err)
		unionfs_check_file(file);
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);
	return err;
}
Esempio n. 10
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;
}
Esempio n. 11
0
static void *unionfs_follow_link(struct dentry *dentry, struct nameidata *nd)
{
	char *buf;
	int len = PAGE_SIZE, err;
	mm_segment_t old_fs;
	struct dentry *parent;

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

	/* This is freed by the put_link method assuming a successful call. */
	buf = kmalloc(len, GFP_KERNEL);
	if (unlikely(!buf)) {
		err = -ENOMEM;
		goto out;
	}

	/* read the symlink, and then we will follow it */
	old_fs = get_fs();
	set_fs(KERNEL_DS);
	err = __unionfs_readlink(dentry, buf, len);
	set_fs(old_fs);
	if (err < 0) {
		kfree(buf);
		buf = NULL;
		goto out;
	}
	buf[err] = 0;
	nd_set_link(nd, buf);
	err = 0;

out:
	if (err >= 0) {
		unionfs_check_nd(nd);
		unionfs_check_dentry(dentry);
	}

	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);

	return ERR_PTR(err);
}
Esempio n. 12
0
/* this @nd *IS* still used */
static void unionfs_put_link(struct dentry *dentry, struct nameidata *nd,
			     void *cookie)
{
	struct dentry *parent;

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

	if (unlikely(!__unionfs_d_revalidate(dentry, parent, false)))
		printk(KERN_ERR
		       "unionfs: put_link failed to revalidate dentry\n");

	unionfs_check_dentry(dentry);
	unionfs_check_nd(nd);
	kfree(nd_get_link(nd));
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);
}
Esempio n. 13
0
long unionfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	long err;
	struct dentry *dentry = file->f_path.dentry;
	struct dentry *parent;

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

	err = unionfs_file_revalidate(file, parent, true);
	if (unlikely(err))
		goto out;

	/* check if asked for local commands */
	switch (cmd) {
	case UNIONFS_IOCTL_INCGEN:
		/* Increment the superblock generation count */
		pr_info("unionfs: incgen ioctl deprecated; "
			"use \"-o remount,incgen\"\n");
		err = -ENOSYS;
		break;

	case UNIONFS_IOCTL_QUERYFILE:
		/* Return list of branches containing the given file */
		err = unionfs_ioctl_queryfile(file, parent, cmd, arg);
		break;

	default:
		/* pass the ioctl down */
		err = do_ioctl(file, cmd, arg);
		break;
	}

out:
	unionfs_check_file(file);
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);
	return err;
}
Esempio n. 14
0
int unionfs_flush(struct file *file, fl_owner_t id)
{
	int err = 0;
	struct file *lower_file = NULL;
	struct dentry *dentry = file->f_path.dentry;
	struct dentry *parent;
	int bindex, bstart, bend;

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

	err = unionfs_file_revalidate(file, parent,
				      UNIONFS_F(file)->wrote_to_file);
	if (unlikely(err))
		goto out;
	unionfs_check_file(file);

	bstart = fbstart(file);
	bend = fbend(file);
	for (bindex = bstart; bindex <= bend; bindex++) {
		lower_file = unionfs_lower_file_idx(file, bindex);

		if (lower_file && lower_file->f_op &&
		    lower_file->f_op->flush) {
			err = lower_file->f_op->flush(lower_file, id);
			if (err)
				goto out;
		}

	}

out:
	if (!err)
		unionfs_check_file(file);
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);
	return err;
}
Esempio n. 15
0
static int unionfs_readdir(struct file *file, void *dirent, filldir_t filldir)
{
	int err = 0;
	struct file *lower_file = NULL;
	struct dentry *dentry = file->f_path.dentry;
	struct dentry *parent;
	struct inode *inode = NULL;
	struct unionfs_getdents_callback buf;
	struct unionfs_dir_state *uds;
	int bend;
	loff_t offset;

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

	err = unionfs_file_revalidate(file, parent, false);
	if (unlikely(err))
		goto out;

	inode = dentry->d_inode;

	uds = UNIONFS_F(file)->rdstate;
	if (!uds) {
		if (file->f_pos == DIREOF) {
			goto out;
		} else if (file->f_pos > 0) {
			uds = find_rdstate(inode, file->f_pos);
			if (unlikely(!uds)) {
				err = -ESTALE;
				goto out;
			}
			UNIONFS_F(file)->rdstate = uds;
		} else {
			init_rdstate(file);
			uds = UNIONFS_F(file)->rdstate;
		}
	}
	bend = fbend(file);

	while (uds->bindex <= bend) {
		lower_file = unionfs_lower_file_idx(file, uds->bindex);
		if (!lower_file) {
			uds->bindex++;
			uds->dirpos = 0;
			continue;
		}

		/* prepare callback buffer */
		buf.filldir_called = 0;
		buf.filldir_error = 0;
		buf.entries_written = 0;
		buf.dirent = dirent;
		buf.filldir = filldir;
		buf.rdstate = uds;
		buf.sb = inode->i_sb;

		/* Read starting from where we last left off. */
		offset = vfs_llseek(lower_file, uds->dirpos, SEEK_SET);
		if (offset < 0) {
			err = offset;
			goto out;
		}
		err = vfs_readdir(lower_file, unionfs_filldir, &buf);

		/* Save the position for when we continue. */
		offset = vfs_llseek(lower_file, 0, SEEK_CUR);
		if (offset < 0) {
			err = offset;
			goto out;
		}
		uds->dirpos = offset;

		/* Copy the atime. */
		fsstack_copy_attr_atime(inode,
					lower_file->f_path.dentry->d_inode);

		if (err < 0)
			goto out;

		if (buf.filldir_error)
			break;

		if (!buf.entries_written) {
			uds->bindex++;
			uds->dirpos = 0;
		}
	}

	if (!buf.filldir_error && uds->bindex >= bend) {
		/* Save the number of hash entries for next time. */
		UNIONFS_I(inode)->hashsize = uds->hashentries;
		free_rdstate(uds);
		UNIONFS_F(file)->rdstate = NULL;
		file->f_pos = DIREOF;
	} else {
		file->f_pos = rdstate2offset(uds);
	}

out:
	if (!err)
		unionfs_check_file(file);
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);
	return err;
}
Esempio n. 16
0
/*
 * This is not meant to be a generic repositioning function.  If you do
 * things that aren't supported, then we return EINVAL.
 *
 * What is allowed:
 *  (1) seeking to the same position that you are currently at
 *	This really has no effect, but returns where you are.
 *  (2) seeking to the beginning of the file
 *	This throws out all state, and lets you begin again.
 */
static loff_t unionfs_dir_llseek(struct file *file, loff_t offset, int origin)
{
	struct unionfs_dir_state *rdstate;
	struct dentry *dentry = file->f_path.dentry;
	struct dentry *parent;
	loff_t err;

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

	err = unionfs_file_revalidate(file, parent, false);
	if (unlikely(err))
		goto out;

	rdstate = UNIONFS_F(file)->rdstate;

	/*
	 * we let users seek to their current position, but not anywhere
	 * else.
	 */
	if (!offset) {
		switch (origin) {
		case SEEK_SET:
			if (rdstate) {
				free_rdstate(rdstate);
				UNIONFS_F(file)->rdstate = NULL;
			}
			init_rdstate(file);
			err = 0;
			break;
		case SEEK_CUR:
			err = file->f_pos;
			break;
		case SEEK_END:
			/* Unsupported, because we would break everything.  */
			err = -EINVAL;
			break;
		}
	} else {
		switch (origin) {
		case SEEK_SET:
			if (rdstate) {
				if (offset == rdstate2offset(rdstate))
					err = offset;
				else if (file->f_pos == DIREOF)
					err = DIREOF;
				else
					err = -EINVAL;
			} else {
				struct inode *inode;
				inode = dentry->d_inode;
				rdstate = find_rdstate(inode, offset);
				if (rdstate) {
					UNIONFS_F(file)->rdstate = rdstate;
					err = rdstate->offset;
				} else {
					err = -EINVAL;
				}
			}
			break;
		case SEEK_CUR:
		case SEEK_END:
			/* Unsupported, because we would break everything.  */
			err = -EINVAL;
			break;
		}
	}

out:
	if (!err)
		unionfs_check_file(file);
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);
	return err;
}
Esempio n. 17
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;
}
Esempio n. 18
0
static int unionfs_setattr(struct dentry *dentry, struct iattr *ia)
{
	int err = 0;
	struct dentry *lower_dentry;
	struct dentry *parent;
	struct inode *inode;
	struct inode *lower_inode;
	int bstart, bend, bindex;
	loff_t size;
	struct iattr lower_ia;

	/* check if user has permission to change inode */
	err = inode_change_ok(dentry->d_inode, ia);
	if (err)
		goto out_err;

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

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

	bstart = dbstart(dentry);
	bend = dbend(dentry);
	inode = dentry->d_inode;

	/*
	 * mode change is for clearing setuid/setgid. Allow lower filesystem
	 * to reinterpret it in its own way.
	 */
	if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
		ia->ia_valid &= ~ATTR_MODE;

	lower_dentry = unionfs_lower_dentry(dentry);
	if (!lower_dentry) { /* should never happen after above revalidate */
		err = -EINVAL;
		goto out;
	}

	/*
	 * Get the lower inode directly from lower dentry, in case ibstart
	 * is -1 (which happens when the file is open but unlinked.
	 */
	lower_inode = lower_dentry->d_inode;

	/* check if user has permission to change lower inode */
	err = inode_change_ok(lower_inode, ia);
	if (err)
		goto out;

	/* copyup if the file is on a read only branch */
	if (is_robranch_super(dentry->d_sb, bstart)
	    || __is_rdonly(lower_inode)) {
		/* check if we have a branch to copy up to */
		if (bstart <= 0) {
			err = -EACCES;
			goto out;
		}

		if (ia->ia_valid & ATTR_SIZE)
			size = ia->ia_size;
		else
			size = i_size_read(inode);
		/* copyup to next available branch */
		for (bindex = bstart - 1; bindex >= 0; bindex--) {
			err = copyup_dentry(parent->d_inode,
					    dentry, bstart, bindex,
					    dentry->d_name.name,
					    dentry->d_name.len,
					    NULL, size);
			if (!err)
				break;
		}
		if (err)
			goto out;
		/* get updated lower_dentry/inode after copyup */
		lower_dentry = unionfs_lower_dentry(dentry);
		lower_inode = unionfs_lower_inode(inode);
		/*
		 * check for whiteouts in writeable branch, and remove them
		 * if necessary.
		 */
		if (lower_dentry) {
			err = check_unlink_whiteout(dentry, lower_dentry,
						    bindex);
			if (err > 0) /* ignore if whiteout found and removed */
				err = 0;
		}
	}

	/*
	 * If shrinking, first truncate upper level to cancel writing dirty
	 * pages beyond the new eof; and also if its' maxbytes is more
	 * limiting (fail with -EFBIG before making any change to the lower
	 * level).  There is no need to vmtruncate the upper level
	 * afterwards in the other cases: we fsstack_copy_inode_size from
	 * the lower level.
	 */
	if (ia->ia_valid & ATTR_SIZE) {
		err = inode_newsize_ok(inode, ia->ia_size);
		if (err)
			goto out;
		truncate_setsize(inode, ia->ia_size);
	}

	/* notify the (possibly copied-up) lower inode */
	/*
	 * Note: we use lower_dentry->d_inode, because lower_inode may be
	 * unlinked (no inode->i_sb and i_ino==0.  This happens if someone
	 * tries to open(), unlink(), then ftruncate() a file.
	 */
	/* prepare our own lower struct iattr (with our own lower file) */
	memcpy(&lower_ia, ia, sizeof(lower_ia));
	if (ia->ia_valid & ATTR_FILE) {
		lower_ia.ia_file = unionfs_lower_file(ia->ia_file);
		BUG_ON(!lower_ia.ia_file); // XXX?
	}

	mutex_lock(&lower_dentry->d_inode->i_mutex);
	err = notify_change(lower_dentry, &lower_ia);
	mutex_unlock(&lower_dentry->d_inode->i_mutex);
	if (err)
		goto out;

	/* get attributes from the first lower inode */
	if (ibstart(inode) >= 0)
		unionfs_copy_attr_all(inode, lower_inode);
	/*
	 * unionfs_copy_attr_all will copy the lower times to our inode if
	 * the lower ones are newer (useful for cache coherency).  However,
	 * ->setattr is the only place in which we may have to copy the
	 * lower inode times absolutely, to support utimes(2).
	 */
	if (ia->ia_valid & ATTR_MTIME_SET)
		inode->i_mtime = lower_inode->i_mtime;
	if (ia->ia_valid & ATTR_CTIME)
		inode->i_ctime = lower_inode->i_ctime;
	if (ia->ia_valid & ATTR_ATIME_SET)
		inode->i_atime = lower_inode->i_atime;
	fsstack_copy_inode_size(inode, lower_inode);

out:
	if (!err)
		unionfs_check_dentry(dentry);
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);
out_err:
	return err;
}
Esempio n. 19
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;
}
Esempio n. 20
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;
}
Esempio n. 21
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;
}
Esempio n. 22
0
/*
 * release all lower object references & free the file info structure
 *
 * No need to grab sb info's rwsem.
 */
int unionfs_file_release(struct inode *inode, struct file *file)
{
	struct file *lower_file = NULL;
	struct unionfs_file_info *fileinfo;
	struct unionfs_inode_info *inodeinfo;
	struct super_block *sb = inode->i_sb;
	struct dentry *dentry = file->f_path.dentry;
	struct dentry *parent;
	int bindex, bstart, bend;
	int fgen, err = 0;

	/*
	 * Since mm/memory.c:might_fault() (under PROVE_LOCKING) was
	 * modified in 2.6.29-rc1 to call might_lock_read on mmap_sem, this
	 * has been causing false positives in file system stacking layers.
	 * In particular, our ->mmap is called after sys_mmap2 already holds
	 * mmap_sem, then we lock our own mutexes; but earlier, it's
	 * possible for lockdep to have locked our mutexes first, and then
	 * we call a lower ->readdir which could call might_fault.  The
	 * different ordering of the locks is what lockdep complains about
	 * -- unnecessarily.  Therefore, we have no choice but to tell
	 * lockdep to temporarily turn off lockdep here.  Note: the comments
	 * inside might_sleep also suggest that it would have been
	 * nicer to only annotate paths that needs that might_lock_read.
	 */
	lockdep_off();
	unionfs_read_lock(sb, UNIONFS_SMUTEX_PARENT);
	parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);

	/*
	 * We try to revalidate, but the VFS ignores return return values
	 * from file->release, so we must always try to succeed here,
	 * including to do the kfree and dput below.  So if revalidation
	 * failed, all we can do is print some message and keep going.
	 */
	err = unionfs_file_revalidate(file, parent,
				      UNIONFS_F(file)->wrote_to_file);
	if (!err)
		unionfs_check_file(file);
	fileinfo = UNIONFS_F(file);
	BUG_ON(file->f_path.dentry->d_inode != inode);
	inodeinfo = UNIONFS_I(inode);

	/* fput all the lower files */
	fgen = atomic_read(&fileinfo->generation);
	bstart = fbstart(file);
	bend = fbend(file);

	for (bindex = bstart; bindex <= bend; bindex++) {
		lower_file = unionfs_lower_file_idx(file, bindex);

		if (lower_file) {
			unionfs_set_lower_file_idx(file, bindex, NULL);
			fput(lower_file);
			branchput(sb, bindex);
		}

		/* if there are no more refs to the dentry, dput it */
		if (d_deleted(dentry)) {
			dput(unionfs_lower_dentry_idx(dentry, bindex));
			unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
		}
	}

	kfree(fileinfo->lower_files);
	kfree(fileinfo->saved_branch_ids);

	if (fileinfo->rdstate) {
		fileinfo->rdstate->access = jiffies;
		spin_lock(&inodeinfo->rdlock);
		inodeinfo->rdcount++;
		list_add_tail(&fileinfo->rdstate->cache,
			      &inodeinfo->readdircache);
		mark_inode_dirty(inode);
		spin_unlock(&inodeinfo->rdlock);
		fileinfo->rdstate = NULL;
	}
	kfree(fileinfo);

	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(sb);
	lockdep_on();
	return err;
}