Unverified Commit 29349a3d authored by Christian Brauner's avatar Christian Brauner
Browse files

Merge patch series "ovl: allow O_PATH file descriptor when specifying layers" 

Christian Brauner <brauner@kernel.org> says:

Allow overlayfs to use O_PATH file descriptors when specifying layers.
Userspace must currently use non-O_PATH file desriptors which is often
pointless especially if the file descriptors have been created via
open_tree(OPEN_TREE_CLONE). This has been a frequent request and came up
again in [1].

Link: https://lore.kernel.org/r/fd8f6574-f737-4743-b220-79c815ee1554@mbaynton.com [1]

* patches from https://lore.kernel.org/r/20250210-work-overlayfs-v2-0-ed2a949b674b@kernel.org:
  selftests/overlayfs: test specifying layers as O_PATH file descriptors
  fs: support O_PATH fds with FSCONFIG_SET_FD

Link: https://lore.kernel.org/r/20250210-work-overlayfs-v2-0-ed2a949b674b@kernel.org


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parents 2cc0b7fd 85c8700c

fs/autofs/autofs_i.h

+2 −0
Original line number Diff line number Diff line
@@ -218,6 +218,8 @@ void autofs_clean_ino(struct autofs_info *); 


static inline int autofs_check_pipe(struct file *pipe)

{

	if (pipe->f_mode & FMODE_PATH)

		return -EINVAL;

	if (!(pipe->f_mode & FMODE_CAN_WRITE))

		return -EINVAL;

	if (!S_ISFIFO(file_inode(pipe)->i_mode))

fs/fsopen.c

+1 −1
Original line number Diff line number Diff line
@@ -453,7 +453,7 @@ SYSCALL_DEFINE5(fsconfig, 
	case FSCONFIG_SET_FD:

		param.type = fs_value_is_file;

		ret = -EBADF;

		param.file = fget(aux);

		param.file = fget_raw(aux);

		if (!param.file)

			goto out_key;

		param.dirfd = aux;

tools/testing/selftests/filesystems/overlayfs/set_layers_via_fds.c

+65 −0
Original line number Diff line number Diff line
@@ -214,4 +214,69 @@ TEST_F(set_layers_via_fds, set_500_layers_via_fds) 
	ASSERT_EQ(close(fd_overlay), 0);

}



TEST_F(set_layers_via_fds, set_500_layers_via_opath_fds)

{

	int fd_context, fd_tmpfs, fd_overlay, fd_work, fd_upper, fd_lower;

	int layer_fds[500] = { [0 ... 499] = -EBADF };



	ASSERT_EQ(unshare(CLONE_NEWNS), 0);

	ASSERT_EQ(sys_mount(NULL, "/", NULL, MS_SLAVE | MS_REC, NULL), 0);



	fd_context = sys_fsopen("tmpfs", 0);

	ASSERT_GE(fd_context, 0);



	ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_CMD_CREATE, NULL, NULL, 0), 0);

	fd_tmpfs = sys_fsmount(fd_context, 0, 0);

	ASSERT_GE(fd_tmpfs, 0);

	ASSERT_EQ(close(fd_context), 0);



	for (int i = 0; i < ARRAY_SIZE(layer_fds); i++) {

		char path[100];



		sprintf(path, "l%d", i);

		ASSERT_EQ(mkdirat(fd_tmpfs, path, 0755), 0);

		layer_fds[i] = openat(fd_tmpfs, path, O_DIRECTORY | O_PATH);

		ASSERT_GE(layer_fds[i], 0);

	}



	ASSERT_EQ(mkdirat(fd_tmpfs, "w", 0755), 0);

	fd_work = openat(fd_tmpfs, "w", O_DIRECTORY | O_PATH);

	ASSERT_GE(fd_work, 0);



	ASSERT_EQ(mkdirat(fd_tmpfs, "u", 0755), 0);

	fd_upper = openat(fd_tmpfs, "u", O_DIRECTORY | O_PATH);

	ASSERT_GE(fd_upper, 0);



	ASSERT_EQ(mkdirat(fd_tmpfs, "l501", 0755), 0);

	fd_lower = openat(fd_tmpfs, "l501", O_DIRECTORY | O_PATH);

	ASSERT_GE(fd_lower, 0);



	ASSERT_EQ(sys_move_mount(fd_tmpfs, "", -EBADF, "/tmp", MOVE_MOUNT_F_EMPTY_PATH), 0);

	ASSERT_EQ(close(fd_tmpfs), 0);



	fd_context = sys_fsopen("overlay", 0);

	ASSERT_GE(fd_context, 0);



	ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_SET_FD, "workdir",   NULL, fd_work), 0);

	ASSERT_EQ(close(fd_work), 0);



	ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_SET_FD, "upperdir",  NULL, fd_upper), 0);

	ASSERT_EQ(close(fd_upper), 0);



	for (int i = 0; i < ARRAY_SIZE(layer_fds); i++) {

		ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_SET_FD, "lowerdir+", NULL, layer_fds[i]), 0);

		ASSERT_EQ(close(layer_fds[i]), 0);

	}



	ASSERT_NE(sys_fsconfig(fd_context, FSCONFIG_SET_FD, "lowerdir+", NULL, fd_lower), 0);

	ASSERT_EQ(close(fd_lower), 0);



	ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_CMD_CREATE, NULL, NULL, 0), 0);



	fd_overlay = sys_fsmount(fd_context, 0, 0);

	ASSERT_GE(fd_overlay, 0);

	ASSERT_EQ(close(fd_context), 0);

	ASSERT_EQ(close(fd_overlay), 0);

}



TEST_HARNESS_MAIN