[LU-11866] Add lfs pcc_dev commond when add/del PCC backend

• Type: Technical task
• Resolution: Unresolved
• Priority: Minor
• Assignee: Qian Yingjin
• Reporter: Qian Yingjin

Description

Currently we add/del a PCC backend on a client via llite.*.pcc as follows:

lctl set_param llite.*.pcc="add $hsm_root $HSM_ARCHIVE_ID $PROJID"
lctl set_param llite.*.pcc="clear"

 However, when a client has more than 1 Lustre mount points or Lustre filesystem instances，the command above may config the PCC backend on unexpected Lustre filesystem instances or Lustre mount points.

To solve this problem, we need to add a lustre mount when add or clear a PCC backend. This lustre mount point must be same as HSM (lhsmtool_posix) configuration.

After add this Lustre mount point parameter, the command to setup/cleanup PCC should be as follows:

local name=$($LFS getname $mntpnt | cut -d' ' -f1)
lctl set_param llite.$name.pcc="add $hsm_root $HSM_ARCHIVE_ID $PROJID"
lctl set_param llite.$name.pcc="clear"

 Going a step further, we should implement lfs pcc_add/del commands for PCC, and also provide a adminstrator with llapi interface to add/del PCC backend for a dedicated Lustre mount point, these APIs can directly use the code of lfs getname and set_param, no need extra IOCTL to implement it.