使用256m的spi-nand

mtd的分区：
mtd0: 00100000 00040000 "boot0"
mtd1: 00300000 00040000 "uboot"
mtd2: 00100000 00040000 "secure_storage"
mtd3: 0fb00000 00040000 "sys"

Volume ID: 0 (on ubi0)
Type: static
Alignment: 1
Size: 66 LEBs (17031168 bytes, 16.2 MiB)
Data bytes: 16777216 bytes (16.0 MiB)
State: OK
Name: mbr
Character device major/minor: 244:1
-----------------------------------
Volume ID: 1 (on ubi0)
Type: dynamic
Alignment: 1
Size: 69 LEBs (17805312 bytes, 16.9 MiB)
State: OK
Name: boot-resource
Character device major/minor: 244:2
-----------------------------------
Volume ID: 2 (on ubi0)
Type: dynamic
Alignment: 1
Size: 5 LEBs (1290240 bytes, 1.2 MiB)
State: OK
Name: env
Character device major/minor: 244:3
-----------------------------------
Volume ID: 3 (on ubi0)
Type: dynamic
Alignment: 1
Size: 5 LEBs (1290240 bytes, 1.2 MiB)
State: OK
Name: env-redund
Character device major/minor: 244:4
-----------------------------------
Volume ID: 4 (on ubi0)
Type: dynamic
Alignment: 1
Size: 70 LEBs (18063360 bytes, 17.2 MiB)
State: OK
Name: boot
Character device major/minor: 244:5
-----------------------------------
Volume ID: 5 (on ubi0)
Type: dynamic
Alignment: 1
Size: 407 LEBs (105025536 bytes, 100.1 MiB)
State: OK
Name: rootfs
Character device major/minor: 244:6
-----------------------------------
Volume ID: 6 (on ubi0)
Type: dynamic
Alignment: 1
Size: 5 LEBs (1290240 bytes, 1.2 MiB)
State: OK
Name: dsp0
Character device major/minor: 244:7
-----------------------------------
Volume ID: 7 (on ubi0)
Type: dynamic
Alignment: 1
Size: 5 LEBs (1290240 bytes, 1.2 MiB)
State: OK
Name: private
Character device major/minor: 244:8
-----------------------------------
Volume ID: 8 (on ubi0)
Type: dynamic
Alignment: 1
Size: 328 LEBs (84639744 bytes, 80.7 MiB)
State: OK
Name: UDISK
Character device major/minor: 244:9

修改sys_partition.fex分区文件，ubi卷大小是改变了。

但是df命令查看 / 只有29m，不懂这个大小是在哪里修改的。

df -h

Filesystem Size Used Available Use% Mounted on
ubi0_5 29.9M 29.2M 672.0K 98% /
devtmpfs 49.2M 0 49.2M 0% /dev
tmpfs 54.4M 0 54.4M 0% /dev/shm
tmpfs 54.4M 24.0K 54.4M 0% /tmp
tmpfs 54.4M 24.0K 54.4M 0% /run

请教下各位大佬们ubi0_5这个size如何修改