SQL Server 2017 Linux CU1 - MODIFY FILE encountered operating system error 31
I figure out the issue.

Problem:  EXT3 files system is not supported.

https://docs.microsoft.com/en-us/sql/linux/sql-server-linux-setup
File System         XFS or EXT4 (other file systems, such as BTRFS, are unsupported

Solution: Create an EXT4 file system.


Comment the line in /etc/fstab that mounts the ext3 filesystem 


vi /etc/fstab

-mount logical volume

"#/dev/vgsqldata/lvsqldata  /sqldata             ext3    defaults        1 1"

:wq!


Reboot the server


reboot


Check the file system is not mounted


df -kh


Check the linear volume


vgscan

vgdisplay vgsqldata

lvdisplay -v /dev/vgsqldata/lvsqldata


Format the volume as ext4


mkfs.ext4 /dev/vgsqldata/lvsqldata


Mount


mkdir /sqldata

mount -t ext4 /dev/vgsqldata/lvsqldata /sqldata

df -kh

touch /sqldata/test.txt

ls -la /sqldata

rm -rf /sqldata/test.txt


Persist the mount


vi /etc/fstab

-mount logical volume

/dev/vgsqldata/lvsqldata  /sqldata             ext4    defaults        1 1


Change Owner


chown -R mssql:mssql /sqldata

ls -la /

"drwxr-xr-x.   5 mssql mssql  4096 Nov  7 10:43 sqldata"