Android Q开关AVB remount分区，导致OTA升级super分区resize fail_android q 屏蔽super分区

0. 问题平台：Android Q，无AB update，开启dynamic partition，机器专门做OTA升级压测，同一个OTA包在多个机器上升级，仅这台机器升级失败，其他机器升级没问题，且这台机器能正常开机和操作。
1. 看OTA升级的log，异常为扩展system分区失败导致

[liblp]Partition vendor will resize from 0 bytes to 217198592 bytes
[liblp]Not enough free space to expand partition: system
Failed to resize partition system to size 1719984128.
script aborted: assert failed: update_dynamic_partitions(package_extract_file("dynamic_partitions_op_list"))
E:Error in @/cache/recovery/block.map (status 7)
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2. 对比正常的log，分区大小是合法的，问题也就进一步证明与机器关联

[liblp]Partition vendor will resize from 0 bytes to 217198592 bytes
[liblp]Partition system will resize from 0 bytes to 1719984128 bytes
[liblp]Updated logical partition table at slot 0 on device /dev/block/by-name/super
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3. 在异常和正常的机器上执行lpdump，确认异常的机器多了一个scratch分区

------------------------
  Name: scratch
  Group: default
  Attributes: none
  Extents:
    0 .. 559463 linear super 3639448
------------------------
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4. 从Google信息看，adb remount时，就会创建这样的一个分区，
   https://source.android.google.cn/devices/tech/ota/dynamic_partitions/implement?hl=zh-cn#adb-remount

5. 通过如下代码可以确认OTA不会删除scratch分区（属于default group），继而导致异常
   

6. 综上，操作上要复现问题，就是关avb，并adb remount_all之后操作system或vendor分区，填足够多的数据，然后在未关闭AVB的情况，直接进行OTA升级，就能够复现问题。

7. 恢复的方法也就是如下，操作完毕之后，重新使能AVB就可。
   adb disable-verity -> adb remount(创建scratch分区用于存放文件)
   -> adb enable-verity(删除scratch分区，恢复系统镜像)

8. 附上正常异常的lpdump命令执行结果

异常的
Metadata version: 10.0
Metadata size: 516 bytes
Metadata max size: 65536 bytes
Metadata slot count: 2
Partition table:
------------------------
  Name: scratch
  Group: default
  Attributes: none
  Extents:
    0 .. 559463 linear super 3639448
------------------------
  Name: vendor
  Group: group_oem
  Attributes: readonly
  Extents:
    0 .. 424215 linear super 2048
------------------------
  Name: system
  Group: group_oem
  Attributes: readonly
  Extents:
    0 .. 3185727 linear super 426264
------------------------
Block device table:
------------------------
  Partition name: super
  First sector: 2048
  Size: 2150629376 bytes
  Flags: none
------------------------
Group table:
------------------------
  Name: default
  Maximum size: 0 bytes
  Flags: none
------------------------
  Name: group_oem
  Maximum size: 2146435072 bytes
  Flags: none
------------------------

正常的
/cache # lpdump                                                         
Metadata version: 10.0
Metadata size: 440 bytes
Metadata max size: 65536 bytes
Metadata slot count: 2
Partition table:
------------------------
  Name: system
  Group: group_oem
  Attributes: readonly
  Extents:
    0 .. 3185727 linear super 2048
------------------------
  Name: vendor
  Group: group_oem
  Attributes: readonly
  Extents:
    0 .. 424215 linear super 3188736
------------------------
Block device table:
------------------------
  Partition name: super
  First sector: 2048
  Size: 2150629376 bytes
  Flags: none
------------------------
Group table:
------------------------
  Name: default
  Maximum size: 0 bytes
  Flags: none
------------------------
  Name: group_oem
  Maximum size: 2146435072 bytes
  Flags: none
------------------------
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