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Commit a8104a9f authored by Al Viro's avatar Al Viro
Browse files

pull mnt_want_write()/mnt_drop_write() into kern_path_create()/done_path_create() resp. 



One side effect - attempt to create a cross-device link on a read-only fs fails
with EROFS instead of EXDEV now.  Makes more sense, POSIX allows, etc.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 8e4bfca1

fs/namei.c

+18 −39
Original line number Original line Diff line number Diff line
@@ -2865,10 +2865,11 @@ struct dentry *kern_path_create(int dfd, const char *pathname, struct path *path 
	mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);

	mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);

	dentry = lookup_hash(&nd);

	dentry = lookup_hash(&nd);

	if (IS_ERR(dentry))

	if (IS_ERR(dentry))

		goto fail;

		goto unlock;





	error = -EEXIST;

	if (dentry->d_inode)

	if (dentry->d_inode)

		goto eexist;

		goto fail;

	/*

	/*

	 * Special case - lookup gave negative, but... we had foo/bar/

	 * Special case - lookup gave negative, but... we had foo/bar/

	 * From the vfs_mknod() POV we just have a negative dentry -

	 * From the vfs_mknod() POV we just have a negative dentry -
@@ -2876,16 +2877,18 @@ struct dentry *kern_path_create(int dfd, const char *pathname, struct path *path 
	 * been asking for (non-existent) directory. -ENOENT for you.

	 * been asking for (non-existent) directory. -ENOENT for you.

	 */

	 */

	if (unlikely(!is_dir && nd.last.name[nd.last.len])) {

	if (unlikely(!is_dir && nd.last.name[nd.last.len])) {

		dput(dentry);

		error = -ENOENT;

		dentry = ERR_PTR(-ENOENT);

		goto fail;

		goto fail;

	}

	}

	error = mnt_want_write(nd.path.mnt);

	if (error)

		goto fail;

	*path = nd.path;

	*path = nd.path;

	return dentry;

	return dentry;

eexist:

	dput(dentry);

	dentry = ERR_PTR(-EEXIST);

fail:

fail:

	dput(dentry);

	dentry = ERR_PTR(error);

unlock:

	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);

	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);

out:

out:

	path_put(&nd.path);

	path_put(&nd.path);
@@ -2897,6 +2900,7 @@ void done_path_create(struct path *path, struct dentry *dentry) 
{

{

	dput(dentry);

	dput(dentry);

	mutex_unlock(&path->dentry->d_inode->i_mutex);

	mutex_unlock(&path->dentry->d_inode->i_mutex);

	mnt_drop_write(path->mnt);

	path_put(path);

	path_put(path);

}

}

EXPORT_SYMBOL(done_path_create);

EXPORT_SYMBOL(done_path_create);
@@ -2974,12 +2978,9 @@ SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode, 




	if (!IS_POSIXACL(path.dentry->d_inode))

	if (!IS_POSIXACL(path.dentry->d_inode))

		mode &= ~current_umask();

		mode &= ~current_umask();

	error = mnt_want_write(path.mnt);

	if (error)

		goto out_dput;

	error = security_path_mknod(&path, dentry, mode, dev);

	error = security_path_mknod(&path, dentry, mode, dev);

	if (error)

	if (error)

		goto out_drop_write;

		goto out;

	switch (mode & S_IFMT) {

	switch (mode & S_IFMT) {

		case 0: case S_IFREG:

		case 0: case S_IFREG:

			error = vfs_create(path.dentry->d_inode,dentry,mode,true);

			error = vfs_create(path.dentry->d_inode,dentry,mode,true);
@@ -2992,11 +2993,8 @@ SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode, 
			error = vfs_mknod(path.dentry->d_inode,dentry,mode,0);

			error = vfs_mknod(path.dentry->d_inode,dentry,mode,0);

			break;

			break;

	}

	}

out_drop_write:

out:

	mnt_drop_write(path.mnt);

out_dput:

	done_path_create(&path, dentry);

	done_path_create(&path, dentry);



	return error;

	return error;

}

}
@@ -3042,16 +3040,9 @@ SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode) 




	if (!IS_POSIXACL(path.dentry->d_inode))

	if (!IS_POSIXACL(path.dentry->d_inode))

		mode &= ~current_umask();

		mode &= ~current_umask();

	error = mnt_want_write(path.mnt);

	if (error)

		goto out_dput;

	error = security_path_mkdir(&path, dentry, mode);

	error = security_path_mkdir(&path, dentry, mode);

	if (error)

	if (!error)

		goto out_drop_write;

		error = vfs_mkdir(path.dentry->d_inode, dentry, mode);

		error = vfs_mkdir(path.dentry->d_inode, dentry, mode);

out_drop_write:

	mnt_drop_write(path.mnt);

out_dput:

	done_path_create(&path, dentry);

	done_path_create(&path, dentry);

	return error;

	return error;

}

}
@@ -3326,16 +3317,9 @@ SYSCALL_DEFINE3(symlinkat, const char __user *, oldname, 
	if (IS_ERR(dentry))

	if (IS_ERR(dentry))

		goto out_putname;

		goto out_putname;





	error = mnt_want_write(path.mnt);

	if (error)

		goto out_dput;

	error = security_path_symlink(&path, dentry, from);

	error = security_path_symlink(&path, dentry, from);

	if (error)

	if (!error)

		goto out_drop_write;

		error = vfs_symlink(path.dentry->d_inode, dentry, from);

		error = vfs_symlink(path.dentry->d_inode, dentry, from);

out_drop_write:

	mnt_drop_write(path.mnt);

out_dput:

	done_path_create(&path, dentry);

	done_path_create(&path, dentry);

out_putname:

out_putname:

	putname(from);

	putname(from);
@@ -3436,15 +3420,10 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, 
	error = -EXDEV;

	error = -EXDEV;

	if (old_path.mnt != new_path.mnt)

	if (old_path.mnt != new_path.mnt)

		goto out_dput;

		goto out_dput;

	error = mnt_want_write(new_path.mnt);

	if (error)

		goto out_dput;

	error = security_path_link(old_path.dentry, &new_path, new_dentry);

	error = security_path_link(old_path.dentry, &new_path, new_dentry);

	if (error)

	if (error)

		goto out_drop_write;

		goto out_dput;

	error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry);

	error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry);

out_drop_write:

	mnt_drop_write(new_path.mnt);

out_dput:

out_dput:

	done_path_create(&new_path, new_dentry);

	done_path_create(&new_path, new_dentry);

out:

out:

fs/ocfs2/refcounttree.c

+0 −7
Original line number Original line Diff line number Diff line
@@ -4466,16 +4466,9 @@ int ocfs2_reflink_ioctl(struct inode *inode, 
		goto out_dput;

		goto out_dput;

	}

	}





	error = mnt_want_write(new_path.mnt);

	if (error) {

		mlog_errno(error);

		goto out_dput;

	}



	error = ocfs2_vfs_reflink(old_path.dentry,

	error = ocfs2_vfs_reflink(old_path.dentry,

				  new_path.dentry->d_inode,

				  new_path.dentry->d_inode,

				  new_dentry, preserve);

				  new_dentry, preserve);

	mnt_drop_write(new_path.mnt);

out_dput:

out_dput:

	done_path_create(&new_path, new_dentry);

	done_path_create(&new_path, new_dentry);

out:

out:

net/unix/af_unix.c

+0 −4
Original line number Original line Diff line number Diff line
@@ -876,15 +876,11 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 
		 */

		 */

		mode = S_IFSOCK |

		mode = S_IFSOCK |

		       (SOCK_INODE(sock)->i_mode & ~current_umask());

		       (SOCK_INODE(sock)->i_mode & ~current_umask());

		err = mnt_want_write(path.mnt);

		if (err)

			goto out_mknod_dput;

		err = security_path_mknod(&path, dentry, mode, 0);

		err = security_path_mknod(&path, dentry, mode, 0);

		if (err)

		if (err)

			goto out_mknod_drop_write;

			goto out_mknod_drop_write;

		err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0);

		err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0);

out_mknod_drop_write:

out_mknod_drop_write:

		mnt_drop_write(path.mnt);

		if (err)

		if (err)

			goto out_mknod_dput;

			goto out_mknod_dput;

		mntget(path.mnt);

		mntget(path.mnt);