After setting project quota, df shows incorrect filesystem size.

Issue

• After setting project quota, df shows incorrect filesystem size, which is the same with the bhard.
• Why does df command show incorrect value?
• The size of /dev/mapper/testdata should be 100G.

# xfs_quota -x -c "print" /nfsdata
Filesystem                Pathname
/testdata                     /dev/mapper/testdata  (pquota)
/testdata/com     /dev/mapper/testdata  (project  100, com)

# xfs_quota -x -c 'project -s com' /testdata
# xfs_quota -x -c 'limit -p bhard=5g com' /testdata

df: 
/dev/mapper/testdata           5242880       4   5242876   1% /testdata