configfs: calculate the depth of parent item

When create symbolic link, create_link should calculate the depth
of the parent item. However, both the first and second parameters
of configfs_get_target_path had been set to the target. Broken
symbolic link created.

$ targetcli ls /
o- / ............................................................. [...]
o- backstores .................................................. [...]
| o- block ...................................... [Storage Objects: 0]
| o- fileio ..................................... [Storage Objects: 2]
| | o- vdev0 .......... [/dev/ramdisk1 (16.0MiB) write-thru activated]
| | | o- alua ....................................... [ALUA Groups: 1]
| | | o- default_tg_pt_gp ........... [ALUA state: Active/optimized]
| | o- vdev1 .......... [/dev/ramdisk2 (16.0MiB) write-thru activated]
| | o- alua ....................................... [ALUA Groups: 1]
| | o- default_tg_pt_gp ........... [ALUA state: Active/optimized]
| o- pscsi ...................................... [Storage Objects: 0]
| o- ramdisk .................................... [Storage Objects: 0]
o- iscsi ................................................ [Targets: 0]
o- loopback ............................................. [Targets: 0]
o- srpt ................................................. [Targets: 2]
| o- ib.e89a8f91cb3200000000000000000000 ............... [no-gen-acls]
| | o- acls ................................................ [ACLs: 2]
| | | o- ib.e89a8f91cb3200000000000000000000 ........ [Mapped LUNs: 2]
| | | | o- mapped_lun0 ............................. [BROKEN LUN LINK]
| | | | o- mapped_lun1 ............................. [BROKEN LUN LINK]
| | | o- ib.e89a8f91cb3300000000000000000000 ........ [Mapped LUNs: 2]
| | | o- mapped_lun0 ............................. [BROKEN LUN LINK]
| | | o- mapped_lun1 ............................. [BROKEN LUN LINK]
| | o- luns ................................................ [LUNs: 2]
| | o- lun0 ...... [fileio/vdev0 (/dev/ramdisk1) (default_tg_pt_gp)]
| | o- lun1 ...... [fileio/vdev1 (/dev/ramdisk2) (default_tg_pt_gp)]
| o- ib.e89a8f91cb3300000000000000000000 ............... [no-gen-acls]
| o- acls ................................................ [ACLs: 0]
| o- luns ................................................ [LUNs: 0]
o- vhost ................................................ [Targets: 0]

Fixes: e9c03af21cc7 ("configfs: calculate the symlink target only once")
Signed-off-by: Honggang Li <[e-mail]>
Signed-off-by: Christoph Hellwig <[e-mail]>

fs/configfs/symlink.c

···
 	}
 	target_sd->s_links++;
 	spin_unlock(&configfs_dirent_lock);
-	ret = configfs_get_target_path(item, item, body);
+	ret = configfs_get_target_path(parent_item, item, body);
 	if (!ret)
 		ret = configfs_create_link(target_sd, parent_item->ci_dentry,
 					   dentry, body);