[LU-12746] max_read_ahead_async_active can't set 0 from non-zero

• Type: Bug
• Resolution: Won't Fix
• Priority: Minor
• Environment: master
• Severity: 3
• Assignee: Wang Shilong (Inactive)
• Reporter: Shuichi Ihara

Description

max_read_ahead_async_active can't be back to 0 (default value) from non-zero value.

# mount -t lustre 10.0.11.220@o2ib10:/scratch0 /scratch0
# lctl get_param  llite.*.max_read_ahead_async_active
llite.scratch0-ffff8f1e453f3800.max_read_ahead_async_active=0
# lctl set_param  llite.*.max_read_ahead_async_active=256
llite.scratch0-ffff8f1e453f3800.max_read_ahead_async_active=256

# lctl set_param  llite.*.max_read_ahead_async_active=0
error: set_param: setting /sys/fs/lustre/llite/scratch0-ffff8f1e453f3800/max_read_ahead_async_active=0: Numerical result out of range

# lctl get_param  llite.*.max_read_ahead_async_active
llite.scratch0-ffff8f1e453f3800.max_read_ahead_async_active=256