[LTP] [PATCH 1/2] lib: limit the size of tmpfs in LTP

[Cyril Hrubis]

Hi!
> Suggested-by: Cyril Hrubis <chrubis@suse.cz>
> Signed-off-by: Li Wang <liwang@redhat.com>
> ---
>  include/tst_device.h |  7 +++++++
>  lib/tst_device.c     | 15 +++++++++++++++
>  lib/tst_test.c       | 10 ++++++++++
>  3 files changed, 32 insertions(+)
> 
> diff --git a/include/tst_device.h b/include/tst_device.h
> index 1d1246e82..51bde4190 100644
> --- a/include/tst_device.h
> +++ b/include/tst_device.h
> @@ -31,6 +31,13 @@ int tst_umount(const char *path);
>  int tst_is_mounted(const char *path);
>  int tst_is_mounted_at_tmpdir(const char *path);
>  
> +/*
> + * Limit the tmpfs mount size for LTP test
> + * @mnt_data: mount options from tst_test->mnt_data
> + * @size: tmpfs size to be mounted
> + */
> +char *limit_tmpfs_mount_size(const char *mnt_data, unsigned int size);

If we want this function to be public it has to be prefixed with 'tst_'.

Also do we really need this to be public?

>  /*
>   * Clears a first few blocks of the device. This is needed when device has
>   * already been formatted with a filesystems, subset of mkfs.foo utils aborts
> diff --git a/lib/tst_device.c b/lib/tst_device.c
> index c096b418b..66a830b7b 100644
> --- a/lib/tst_device.c
> +++ b/lib/tst_device.c
> @@ -45,6 +45,7 @@
>  #define DEV_FILE "test_dev.img"
>  #define DEV_SIZE_MB 256u
>  
> +static char tmpfs_buf[1024];

Can we please, instead of adding a global variable, pass the buffer and
it's size to the limit_tmpfs_mount size, and then create the path on the
stack in the prepare device function?

>  static char dev_path[1024];
>  static int device_acquired;
>  static unsigned long prev_dev_sec_write;
> @@ -368,6 +369,20 @@ int tst_clear_device(const char *dev)
>  	return 0;
>  }
>  
> +char *limit_tmpfs_mount_size(const char *mnt_data, unsigned int size)
> +{
> +	unsigned int dev_size = MAX(size, DEV_SIZE_MB);
> +
> +	if (mnt_data)
> +		snprintf(tmpfs_buf, sizeof(tmpfs_buf), "%s,size=%uM", mnt_data, dev_size);
> +	else
> +		snprintf(tmpfs_buf, sizeof(tmpfs_buf), "size=%uM", dev_size);
> +
> +	tst_resm(TINFO, "Limiting tmpfs size to %uMB", dev_size);
> +
> +	return tmpfs_buf;
> +}

If we passed the filesystem type to this function here as well we could
do:

	if (!strcmp(fs_type, "tmpfs"))
		return mnt_data;

As a first thing in this function and then we could pass the return
value from this function to the SAFE_MOUNT() unconditionally.

>  int tst_umount(const char *path)
>  {
>  	int err, ret, i;
> diff --git a/lib/tst_test.c b/lib/tst_test.c
> index 55449c80b..27766fbfd 100644
> --- a/lib/tst_test.c
> +++ b/lib/tst_test.c
> @@ -896,9 +896,19 @@ static void prepare_device(void)
>  	}
>  
>  	if (tst_test->mount_device) {
> +		char *mnt_data = tst_test->mnt_data;
> +
> +		if (!strcmp(tdev.fs_type, "tmpfs")) {
> +			tst_test->mnt_data = limit_tmpfs_mount_size(tst_test->mnt_data,
> +					tst_test->dev_min_size);
> +		}
> +
>  		SAFE_MOUNT(tdev.dev, tst_test->mntpoint, tdev.fs_type,
>  			   tst_test->mnt_flags, tst_test->mnt_data);
>  		mntpoint_mounted = 1;
> +
> +		if (!strcmp(tdev.fs_type, "tmpfs"))
> +			tst_test->mnt_data = mnt_data;

I guess that we are doing this in order to export the changes in the
mnt_data to the test, right?

Is that needed for something or are you doing this just in a case that
somebody will use that?

>  	}
>  }
>  
> -- 
> 2.31.1
> 

-- 
Cyril Hrubis
chrubis@suse.cz