[LTP] [PATCH v5 1/2] OVL_MNT: add helpers to setup overlayfs mountpoint

[Amir Goldstein]

On Wed, May 29, 2019 at 1:19 PM Murphy Zhou <xzhou@redhat.com> wrote:
>
> Introduce tst_test->needs_overlay;
> Define constraints of needed overlayfs dirs;
> create_overlay_dirs() to create lower/upper/work dirs;
> mount_overlay() to mount overlayfs;
> SAFE_MOUNT_OVERLAY macro to mount overlayfs safely, tst_brk TCONF
> if mount fail with errno ENODEV;
> TST_MOUNT_OVERLAY  macro to mount overlayfs and return 0 if succeeds;
>
> Suggested-by: Petr Vorel <pvorel@suse.cz>
> Suggested-by: Amir Goldstein <amir73il@gmail.com>
> Signed-off-by: Murphy Zhou <xzhou@redhat.com>
> ---

Very nice! just one minor comment, otherwise

Reviewed-by: Amir Goldstein <amir73il@gmail.com>

> v5:
>   Introduce tst_test->needs_overlay to mount and umount overlay
>   Several other fixes suggested by Petr
>   Update execveat03, inotify07/8 to use needs_overlay
> v4:
>   Update ENODEV handle logic
>   Define TST_MOUNT_OVERLAY and SAFE_MOUNT_OVERLAY macros
>   Change helper names
> v3:
>   Split setup to 2 parts: creating files and mounting.
>   Use macro SAFE_MOUNT_OVERLAYFS.
>   Handle ENODEV differently for 4 testcases we have modified.
> v2:
>   define constraints in header file.
>   add a setup helper to create dirs and mount.
>  include/safe_file_ops_fn.h  |  4 ++++
>  include/tst_fs.h            |  6 +++++
>  include/tst_safe_file_ops.h |  6 +++++
>  include/tst_test.h          |  1 +
>  lib/tst_fs_setup.c          | 48 +++++++++++++++++++++++++++++++++++++
>  lib/tst_test.c              | 15 ++++++++++++
>  6 files changed, 80 insertions(+)
>  create mode 100644 lib/tst_fs_setup.c
>
> diff --git a/include/safe_file_ops_fn.h b/include/safe_file_ops_fn.h
> index 35ec4fb1f..052fb1b9a 100644
> --- a/include/safe_file_ops_fn.h
> +++ b/include/safe_file_ops_fn.h
> @@ -76,4 +76,8 @@ void safe_touch(const char *file, const int lineno,
>                 const char *pathname,
>                 mode_t mode, const struct timespec times[2]);
>
> +/* helper functions to setup overlayfs mountpoint */
> +void create_overlay_dirs(void);
> +int mount_overlay(const char *file, const int lineno, int skip);
> +
>  #endif /* SAFE_FILE_OPS_FN */
> diff --git a/include/tst_fs.h b/include/tst_fs.h
> index b2b19ada6..ebca065c6 100644
> --- a/include/tst_fs.h
> +++ b/include/tst_fs.h
> @@ -50,6 +50,12 @@ enum {
>         TST_GB = 1073741824,
>  };
>
> +#define OVL_BASE_MNTPOINT        "mntpoint"
> +#define OVL_LOWER      OVL_BASE_MNTPOINT"/lower"
> +#define OVL_UPPER      OVL_BASE_MNTPOINT"/upper"
> +#define OVL_WORK       OVL_BASE_MNTPOINT"/work"
> +#define OVL_MNT                OVL_BASE_MNTPOINT"/ovl"
> +
>  /*
>   * @path: path is the pathname of any file within the mounted file system
>   * @mult: mult should be TST_KB, TST_MB or TST_GB
> diff --git a/include/tst_safe_file_ops.h b/include/tst_safe_file_ops.h
> index 5c3fea4e2..b62a7447f 100644
> --- a/include/tst_safe_file_ops.h
> +++ b/include/tst_safe_file_ops.h
> @@ -59,4 +59,10 @@
>         safe_touch(__FILE__, __LINE__, NULL, \
>                         (pathname), (mode), (times))
>
> +#define SAFE_MOUNT_OVERLAY() \
> +       ((void) mount_overlay(__FILE__, __LINE__, 1))
> +
> +#define TST_MOUNT_OVERLAY() \
> +       (mount_overlay(__FILE__, __LINE__, 0) == 0)
> +
>  #endif /* TST_SAFE_FILE_OPS */
> diff --git a/include/tst_test.h b/include/tst_test.h
> index e4b935c45..f3b8901a2 100644
> --- a/include/tst_test.h
> +++ b/include/tst_test.h
> @@ -121,6 +121,7 @@ struct tst_test {
>         int needs_root:1;
>         int forks_child:1;
>         int needs_device:1;
> +       int needs_overlay:1;
>         int needs_checkpoints:1;
>         int format_device:1;
>         int mount_device:1;
> diff --git a/lib/tst_fs_setup.c b/lib/tst_fs_setup.c
> new file mode 100644
> index 000000000..e8ae929d7
> --- /dev/null
> +++ b/lib/tst_fs_setup.c
> @@ -0,0 +1,48 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +
> +#include <dirent.h>
> +#include <errno.h>
> +#include <sys/mount.h>
> +
> +#define TST_NO_DEFAULT_MAIN
> +#include "tst_test.h"
> +#include "tst_fs.h"
> +
> +#define TST_FS_SETUP_OVERLAYFS_MSG "overlayfs is not configured in this kernel"
> +#define TST_FS_SETUP_OVERLAYFS_CONFIG "lowerdir="OVL_LOWER",upperdir="OVL_UPPER",workdir="OVL_WORK
> +
> +void create_overlay_dirs(void)
> +{
> +       DIR *dir = opendir(OVL_LOWER);
> +       if (dir == NULL) {
> +               SAFE_MKDIR(OVL_LOWER, 0755);
> +               SAFE_MKDIR(OVL_UPPER, 0755);
> +               SAFE_MKDIR(OVL_WORK, 0755);
> +               SAFE_MKDIR(OVL_MNT, 0755);

return here so we don't closedir(NULL)?

> +       }
> +       closedir(dir);
> +}
> +

Thanks for doing this work!
Amir.