LVM lvchange - Can't control the behavior of writing data to mountpoint?

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Hi community,

I just tested with lvchange --permission r and it worked when showing me that can't make filesystem on LV

[root@huyvl-linux-training ~]# lvchange -pr /dev/vg_database/lv_mysql 
  Logical volume vg_database/lv_mysql changed.
[root@huyvl-linux-training ~]# lvs
  LV       VG          Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  lv_mysql vg_database -ri-a----- 500.00m                                                    
[root@huyvl-linux-training ~]# mkfs.xfs /dev/vg_database/lv_mysql
meta-data=/dev/vg_database/lv_mysql isize=512    agcount=4, agsize=32000 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=1, sparse=1, rmapbt=0
         =                       reflink=1    bigtime=1 inobtcount=1 nrext64=0
data     =                       bsize=4096   blocks=128000, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
log      =internal log           bsize=4096   blocks=16384, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
mkfs.xfs: pwrite failed: Operation not permitted
libxfs_bwrite: write failed on (unknown) bno 0xf9f00/0x100, err=1
mkfs.xfs: Releasing dirty buffer to free list!
found dirty buffer (bulk) on free list!
mkfs.xfs: pwrite failed: Operation not permitted
libxfs_bwrite: write failed on (unknown) bno 0x0/0x100, err=1
mkfs.xfs: Releasing dirty buffer to free list!
found dirty buffer (bulk) on free list!
mkfs.xfs: pwrite failed: Operation not permitted
libxfs_bwrite: write failed on xfs_sb bno 0x0/0x1, err=1
mkfs.xfs: Releasing dirty buffer to free list!
mkfs.xfs: libxfs_device_zero write failed: Operation not permitted
[root@huyvl-linux-training ~]# dd if=/dev/zero of=/dev/vg_database/lv_mysql bs=256MB status=progress
dd: error writing '/dev/vg_database/lv_mysql': Operation not permitted
1+0 records in
0+0 records out
0 bytes copied, 0.0545821 s, 0.0 kB/s
[root@huyvl-linux-training ~]#

, but its not work after mounting. So the permissionreadonly only apply to mounting?

[root@huyvl-linux-training ~]# lvdisplay
  --- Logical volume ---
  LV Path                /dev/vg_database/lv_mysql
  LV Name                lv_mysql
  VG Name                vg_database
  LV UUID                LStLEK-2kNM-kP5D-aWxV-sg23-yclf-Zwh8fs
  LV Write Access        read/write
  LV Creation host, time huyvl-linux-training.novalocal, 2024-02-09 11:13:55 -0500
  LV Status              available
  # open                 1
  LV Size                500.00 MiB
  Current LE             125
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:0

[root@huyvl-linux-training ~]# lvchange --permission r /dev/vg_database/lv_mysql 
  Logical volume vg_database/lv_mysql changed.
[root@huyvl-linux-training ~]# lvs
  LV       VG          Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  lv_mysql vg_database -ri-ao---- 500.00m                                                    
[root@huyvl-linux-training ~]# lsblk -fs /dev/vg_database/lv_mysql
NAME                 FSTYPE      FSVER    LABEL UUID                                   FSAVAIL FSUSE% MOUNTPOINTS
vg_database-lv_mysql xfs                        972f5af2-d899-44cc-bcad-d17831dc897f    407.7M     6% /root/mysql_data
└─vdb1               LVM2_member LVM2 001       LY3xGO-EtdO-OMqR-BsLP-VS6N-Vdwt-SJyXx0                
  └─vdb                                                                                               
[root@huyvl-linux-training ~]# echo `date` >> /root/mysql_data/date.log
[root@huyvl-linux-training ~]# echo `date` >> /root/mysql_data/date.log
[root@huyvl-linux-training ~]# echo `date` >> /root/mysql_data/date.log
[root@huyvl-linux-training ~]# cat /root/mysql_data/date.log
Fri Feb 9 11:14:45 EST 2024
Fri Feb 9 11:14:48 EST 2024
Fri Feb 9 11:14:48 EST 2024
[root@huyvl-linux-training ~]#
HV

Responses