Problem : "mount: '/system/' not in /proc/mounts" in Pixel XL (AOSP sailfish-userdebug)

[rock Duan]

Hi ,every one

 After I build AOSP(lunch aosp_sailfish-userdebug) and flash it to my pixel xl(sailfish),I want to replace framework.jar in /system/framework/,but I found that the /system dir is read only!

I was wonder that Could anybody tell me:

1.How can I solve the problem 

"mount: '/system/' not in /proc/mounts"
2.why there have  two system dir : system_a and system_b under 

/dev/block/platform/soc/624000.ufshc/by-name in my Pixel xl .

here are some ways and infomation I've been tried and get in those days:

1.when I use adb ,it sames that I've been get su permisstion.

E:\julifiles>adb root
adbd is already running as root
E:\julifiles>adb shell
sailfish:/ # su
sailfish:/ #

2.then I tried the command mount,but it no use

sailfish:/ # mount -o remount rw /system
mount: '/system' not in /proc/mounts
1|sailfish:/ # mount -o remount rw /system/
mount: '/system/' not in /proc/mounts
1|sailfish:/ # mount -o remount,rw /system
mount: '/system' not in /proc/mounts
1|sailfish:/ # mount -o remount,rw /system/
mount: '/system/' not in /proc/mounts
1|sailfish:/ #

3.it says that "mount: '/system/' not in /proc/mounts",so I analysis /proc/mounts,the content is:

1|sailfish:/ # mount
rootfs on / type rootfs (rw,seclabel)
/dev/root on / type ext4 (ro,seclabel,relatime,data=ordered)
tmpfs on /dev type tmpfs (rw,seclabel,nosuid,relatime,size=1898704k,nr_inodes=474676,mode=755)
devpts on /dev/pts type devpts (rw,seclabel,relatime,mode=600)
proc on /proc type proc (rw,relatime,gid=3009,hidepid=2)
sysfs on /sys type sysfs (rw,seclabel,relatime)
selinuxfs on /sys/fs/selinux type selinuxfs (rw,relatime)
debugfs on /sys/kernel/debug type debugfs (rw,seclabel,relatime)
none on /acct type cgroup (rw,relatime,cpuacct)
none on /dev/stune type cgroup (rw,relatime,schedtune)
tmpfs on /mnt type tmpfs (rw,seclabel,relatime,size=1898704k,nr_inodes=474676,mode=755,gid=1000)
none on /config type configfs (rw,relatime)
none on /dev/cpuctl type cgroup (rw,relatime,cpu)
none on /dev/cpuset type cgroup (rw,relatime,cpuset,noprefix,release_agent=/sbin/cpuset_release_agent)
pstore on /sys/fs/pstore type pstore (rw,seclabel,relatime)
/dev/block/sda31 on /vendor type ext4 (ro,seclabel,relatime,discard,data=ordered)
/dev/block/sda25 on /firmware/radio type vfat (ro,context=u:object_r:firmware_file:s0,relatime,uid=1000,fmask=0337,dmask=0227,codepage=437,iocharset=iso8859-1,shortname=lower,errors=remount-ro)
/dev/block/sdd3 on /persist type ext4 (rw,seclabel,nosuid,nodev,relatime,data=ordered)
tmpfs on /storage type tmpfs (rw,seclabel,relatime,size=1898704k,nr_inodes=474676,mode=755,gid=1000)
adb on /dev/usb-ffs/adb type functionfs (rw,relatime)
/dev/block/sda35 on /data type ext4 (rw,seclabel,nosuid,nodev,noatime,noauto_da_alloc,data=ordered)
/dev/fuse on /mnt/runtime/default/emulated type fuse (rw,nosuid,nodev,noexec,noatime,user_id=1023,group_id=1023,default_permissions,allow_other)
/dev/fuse on /storage/emulated type fuse (rw,nosuid,nodev,noexec,noatime,user_id=1023,group_id=1023,default_permissions,allow_other)
/dev/fuse on /mnt/runtime/read/emulated type fuse (rw,nosuid,nodev,noexec,noatime,user_id=1023,group_id=1023,default_permissions,allow_other)
/dev/fuse on /mnt/runtime/write/emulated type fuse (rw,nosuid,nodev,noexec,noatime,user_id=1023,group_id=1023,default_permissions,allow_other)
sailfish:/ #

there is no /system dir mounted in /proc/mounts indeed

4.then I compare the /proc/mounts 's diffirences between my pixel xl and another device which can write under /system dir after execute "mount -o remount,rw /system".

the another /proc/mounts is:

rootfs / rootfs ro,relatime 0 0
tmpfs /dev tmpfs rw,nosuid,relatime,mode=755 0 0
devpts /dev/pts devpts rw,relatime,mode=600,ptmxmode=000 0 0
proc /proc proc rw,relatime 0 0
sysfs /sys sysfs rw,relatime 0 0
/dev/block/platform/e0338000.mmc/by-name/MISC /misc vfat ro,noatime,nodiratime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro 0 0
none /acct cgroup rw,relatime,cpuacct 0 0
none /sys/fs/cgroup tmpfs rw,relatime,mode=750,gid=1000 0 0
tmpfs /mnt/asec tmpfs rw,relatime,mode=755,gid=1000 0 0
tmpfs /mnt/obb tmpfs rw,relatime,mode=755,gid=1000 0 0
none /dev/cpuctl cgroup rw,relatime,cpu 0 0
pstore /sys/fs/pstore pstore rw,relatime 0 0
/dev/block/platform/e0338000.mmc/by-name/SYSTEM /system ext4 ro,nodev,noatime,nodiratime,noauto_da_alloc,data=ordered 0 0
/dev/block/platform/e0338000.mmc/by-name/DATA /data ext4 rw,nosuid,nodev,noatime,nodiratime,discard,journal_checksum,noauto_da_alloc,errors=remount-ro,data=ordered 0 0
/dev/block/platform/e0338000.mmc/by-name/CACHE /cache ext4 rw,nosuid,nodev,noatime,nodiratime,discard,journal_checksum,noauto_da_alloc,errors=remount-ro,data=ordered 0 0
none /sys/kernel/debug debugfs rw,relatime 0 0
/dev/fuse /mnt/shell/emulated fuse rw,nosuid,nodev,noexec,relatime,user_id=1023,group_id=1023,default_permissions,allow_other 0 0

there actually exist /system info in as shown above，and because the dir in my pixel xl is like that :

sailfish:/dev/block/platform/soc/624000.ufshc/by-name # ls -al

total 0

drwxr-xr-x 2 root root 1280 1970-06-27 00:34 .

drwxr-xr-x 4 root root 1440 1970-06-27 00:34 ..

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 aboot_a -> /dev/block/sda17

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 aboot_b -> /dev/block/sda18

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 apdp_a -> /dev/block/sda29

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 apdp_b -> /dev/block/sda30

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 board_info -> /dev/block/sdf1

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 boot_a -> /dev/block/sda19

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 boot_b -> /dev/block/sda20

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 bootlocker_a -> /dev/block/sda1

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 bootlocker_b -> /dev/block/sda2

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 cdt -> /dev/block/sdd12

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 cmnlib32_a -> /dev/block/sda13

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 cmnlib32_b -> /dev/block/sda14

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 cmnlib64_a -> /dev/block/sda15

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 cmnlib64_b -> /dev/block/sda16

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 ddr -> /dev/block/sdd11

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 devcfg_a -> /dev/block/sda23

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 devcfg_b -> /dev/block/sda24

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 devinfo -> /dev/block/sdf4

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 devinfobak -> /dev/block/sdd5

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 dip -> /dev/block/sdd7

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 dpo -> /dev/block/sdd6

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 frp -> /dev/block/sde1

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 fsc -> /dev/block/sdd8

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 fsg -> /dev/block/sdf3

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 hosd_a -> /dev/block/sda21

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 hosd_b -> /dev/block/sda22

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 hyp_a -> /dev/block/sda11

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 hyp_b -> /dev/block/sda12

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 keymaster_a -> /dev/block/sda3

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 keymaster_b -> /dev/block/sda4

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 metadata -> /dev/block/sde5

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 mfg -> /dev/block/sdf2

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 misc -> /dev/block/sdd1

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 modem_a -> /dev/block/sda25

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 modem_b -> /dev/block/sda26

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 modemst1 -> /dev/block/sdd9

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 modemst2 -> /dev/block/sdd10

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 msadp_a -> /dev/block/sda27

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 msadp_b -> /dev/block/sda28

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 persist -> /dev/block/sdd3

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 pg1fs -> /dev/block/sde3

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 pg2fs -> /dev/block/sde4

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 pmic_a -> /dev/block/sda9

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 pmic_b -> /dev/block/sda10

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 ramdump -> /dev/block/sde2

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 reserve0 -> /dev/block/sda36

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 reserve3 -> /dev/block/sdd13

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 reserve4 -> /dev/block/sde6

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 reserve5 -> /dev/block/sdf5

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 rpm_a -> /dev/block/sda7

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 rpm_b -> /dev/block/sda8

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 sec -> /dev/block/sdd4

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 ssd -> /dev/block/sdd2

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 system_a -> /dev/block/sda33

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 system_b -> /dev/block/sda34

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 tz_a -> /dev/block/sda5

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 tz_b -> /dev/block/sda6

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 userdata -> /dev/block/sda35

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 vendor_a -> /dev/block/sda31

lrwxrwxrwx 1 root root   16 1970-06-27 00:34 vendor_b -> /dev/block/sda32

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 xbl_a -> /dev/block/sdb1

lrwxrwxrwx 1 root root   15 1970-06-27 00:34 xbl_b -> /dev/block/sdc1

so I add /system 's mount command in /system/core/rootdir/init.rc：

    # Shouldn't be necessary, but sdcard won't start without it. http://b/22568628.
    mkdir /mnt 0775 root system

    #mkdir /system 0777 root system
    mount ext4 /dev/block/platform/soc/624000.ufshc/by-name/system_a /system_a rw,noatime,nodiratime,nodev,noauto_da_alloc wait
    mount ext4 /dev/block/platform/soc/624000.ufshc/by-name/system_b /system_b rw,noatime,nodiratime,nodev,noauto_da_alloc wait
    # Set the security context of /postinstall if present.
    restorecon /postinstall

    start ueventd

on init

5.but it also no use at all  !!! = =..             

   help!

[James Muir]

 After I build AOSP(lunch aosp_sailfish-userdebug) and flash it to my pixel xl(sailfish),I want to replace framework.jar in /system/framework/,but I found that the /system dir is read only!

Just use "adb remount":

$ adb root

restarting adbd as root

$ adb remount

dm_verity is enabled on the system partition.

Use "adb disable-verity" to disable verity.

If you do not, remount may succeed, however, you will still not be able to write to these volumes.

remount succeeded

$ adb disable-verity

Verity disabled on /system

Now reboot your device for settings to take effect

$ adb reboot

$ adb root

restarting adbd as root

$ adb remount

remount succeeded

The Pixel uses a new OTA update mechanism:  A/B system updates.  That is why there are two "system" partitions:

https://source.android.com/devices/tech/ota/ab_updates.html

-James M 

[fancy S]

adb root

adb disable-verity

adb reboot

adb reboot

adb disable-verity

[阿嚏]

在 2017年4月2日星期日 UTC+8上午4:58:52，James Muir写道：

if

mount |grep system

/dev/block/dm-0 on /system type ext4 (ro,seclabel,relatime,discard,data=ordered)

adb disable-verity

This can solve the problem, because this is a dm-verity problem

but, system don't exist in /proc/mount

adb disable-verity can't solve this problem