Commit 648fa861 authored by Al Viro's avatar Al Viro
Browse files

beginning to untangle do_filp_open() 



That's going to be a long and painful series.  The first step:
take the stuff reachable from 'ok' label in do_filp_open() into
a new helper (finish_open()).

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 64ba9926

fs/namei.c

+56 −50
Original line number Diff line number Diff line
@@ -1590,6 +1590,61 @@ static int open_will_truncate(int flag, struct inode *inode) 
	return (flag & O_TRUNC);

}



static struct file *finish_open(struct nameidata *nd,

				int open_flag, int flag, int acc_mode)

{

	struct file *filp;

	int will_truncate;

	int error;



	will_truncate = open_will_truncate(flag, nd->path.dentry->d_inode);

	if (will_truncate) {

		error = mnt_want_write(nd->path.mnt);

		if (error)

			goto exit;

	}

	error = may_open(&nd->path, acc_mode, open_flag);

	if (error) {

		if (will_truncate)

			mnt_drop_write(nd->path.mnt);

		goto exit;

	}

	filp = nameidata_to_filp(nd);

	if (!IS_ERR(filp)) {

		error = ima_file_check(filp, acc_mode);

		if (error) {

			fput(filp);

			filp = ERR_PTR(error);

		}

	}

	if (!IS_ERR(filp)) {

		if (acc_mode & MAY_WRITE)

			vfs_dq_init(nd->path.dentry->d_inode);



		if (will_truncate) {

			error = handle_truncate(&nd->path);

			if (error) {

				fput(filp);

				filp = ERR_PTR(error);

			}

		}

	}

	/*

	 * It is now safe to drop the mnt write

	 * because the filp has had a write taken

	 * on its behalf.

	 */

	if (will_truncate)

		mnt_drop_write(nd->path.mnt);

	return filp;



exit:

	if (!IS_ERR(nd->intent.open.file))

		release_open_intent(nd);

	path_put(&nd->path);

	return ERR_PTR(error);

}



/*

 * Note that the low bits of the passed in "open_flag"

 * are not the same as in the local variable "flag". See
@@ -1604,7 +1659,6 @@ struct file *do_filp_open(int dfd, const char *pathname, 
	struct path path;

	struct dentry *dir;

	int count = 0;

	int will_truncate;

	int flag = open_to_namei_flags(open_flag);

	int force_reval = 0;
@@ -1769,55 +1823,7 @@ struct file *do_filp_open(int dfd, const char *pathname, 
	if (S_ISDIR(path.dentry->d_inode->i_mode))

		goto exit;

ok:

	/*

	 * Consider:

	 * 1. may_open() truncates a file

	 * 2. a rw->ro mount transition occurs

	 * 3. nameidata_to_filp() fails due to

	 *    the ro mount.

	 * That would be inconsistent, and should

	 * be avoided. Taking this mnt write here

	 * ensures that (2) can not occur.

	 */

	will_truncate = open_will_truncate(flag, nd.path.dentry->d_inode);

	if (will_truncate) {

		error = mnt_want_write(nd.path.mnt);

		if (error)

			goto exit;

	}

	error = may_open(&nd.path, acc_mode, open_flag);

	if (error) {

		if (will_truncate)

			mnt_drop_write(nd.path.mnt);

		goto exit;

	}

	filp = nameidata_to_filp(&nd);

	if (!IS_ERR(filp)) {

		error = ima_file_check(filp, acc_mode);

		if (error) {

			fput(filp);

			filp = ERR_PTR(error);

		}

	}

	if (!IS_ERR(filp)) {

		if (acc_mode & MAY_WRITE)

			vfs_dq_init(nd.path.dentry->d_inode);



		if (will_truncate) {

			error = handle_truncate(&nd.path);

			if (error) {

				fput(filp);

				filp = ERR_PTR(error);

			}

		}

	}

	/*

	 * It is now safe to drop the mnt write

	 * because the filp has had a write taken

	 * on its behalf.

	 */

	if (will_truncate)

		mnt_drop_write(nd.path.mnt);

	filp = finish_open(&nd, open_flag, flag, acc_mode);

	if (nd.root.mnt)

		path_put(&nd.root);

	return filp;