How much of flash can be used?

hello,

I want to bulid a custum image and iam not shure how big I can make the root fs

[    1.045933] nand: AMD/Spansion S34ML01G1
[    1.049842] nand: 128 MiB, SLC, erase size: 128 KiB, page size: 2048, OOB siz
e: 64
[    1.057409] iproc_nand 18028000.nand-controller: detected 128MiB total, 128Ki
B blocks, 2KiB pages, 16B OOB, 8-bit, BCH-8
[    1.068248] Scanning device for bad blocks
[    2.232880] Bad eraseblock 900 at 0x000007080000
[    2.237861] Bad eraseblock 901 at 0x0000070a0000
[    3.284168] 5 bcm47xxpart partitions found on MTD device brcmnand.0
[    3.290409] Creating 5 MTD partitions on "brcmnand.0":
[    3.295541] 0x000000000000-0x000000080000 : "boot"
[    3.301088] 0x000000080000-0x000000180000 : "nvram"
[    3.306634] 0x000000180000-0x000000200000 : "nvram"
[    3.312142] 0x000000200000-0x000001f00000 : "firmware"
[    3.320031] 2 trx partitions found on MTD device firmware
[    3.325435] Creating 2 MTD partitions on "firmware":
[    3.330386] 0x00000000001c-0x000000400000 : "linux"
[    3.336068] 0x000000400000-0x000001d00000 : "ubi"
[    3.341841] 0x000001f00000-0x000008000000 : "failsafe"
[    3.348826] bcm_iproc 18029200.spi: using bspi-mspi mode

its a ea6500v2