ubifs: add support for FS_IOC_GETFSSYSFSPATH

In commit ae8c51175730 ("fs: add FS_IOC_GETFSSYSFSPATH"), a
new fs ioctl was introduced to standardize exporting data from
sysfs across filesystems. The returned path will always be of the
form "$FSTYP/$SYSFS_IDENTIFIER", where the sysfs identifier may
be a UUID or a device name.

The ubifs is a file system based on char device, and the common
method to fill s_sysfs_name (super_set_sysfs_name_bdev) is
unavialable. So in order to support FS_IOC_GETFSSYSFSPATH ioctl,
we fill the s_sysfs_name with ubi_volume_info member which keeps
the format defined in macro UBIFS_DFS_DIR_NAME by using
super_set_sysfs_name_generic.

That's for ubifs, it will output "ubifs/<dev>".

```
$ ./ioctl_getfssysfs_path /mnt/ubifs/testfile
path: ubifs/ubi0_0

$ ls /sys/fs/ubifs/ubi0_0/
errors_crc  errors_magic  errors_node
```

Signed-off-by: Hongbo Li <[email protected]>
Reviewed-by: Zhihao Cheng <[email protected]>
Signed-off-by: Richard Weinberger <[email protected]>

0 files changed, 0 insertions, 0 deletions