Ignore Permissions / Different mtimes on Android Sdcard

[rahrah (Richard)]

Hi,

That seem to fix the issue! I wasn’t aware of the setting - sorry.

Preliminary tests seem very positive. I will test again, more extensively, later, but, for now, the fix seems good (for me)!

Thank you!

===R

[imsodin (Simon)]

Good to know, thanks for reporting. That setting it to 2 has an effect also means there’s something not working as expected with the FS auto-detection (if @Catfriend1’s apk is up-to-date, which I think it is, right?).

[Catfriend1]

@imsodin what line do I need to throw in to see if fs auto detect is working? Maybe you could add the log line to your PR as this would give us a lot of info what different Android OS report via gopsutil.

[imsodin (Simon)]

Done. Enable config debug logging and there will be lines about detecting FS at ... on android ... with the relevant information. Thanks!

[Catfriend1]

Thanks for all your efforts on this, @imsodin. Unfortunately I have to report back with no good news. We’re almost game over with SDcards I think… details are on Override/Revert showing up with no changes on extSdCard synced folders · Issue #454 · Catfriend1/syncthing-android · GitHub .

Short summary:

• I’ve synced a file (like in my previous test scenario from PR #5852) from PC to phone. The file is created on the phone with the correct “original” mtime on sdcard. I exit the app, verify the original mtime is still there and reboot the phone. I ensure to NOT start the Syncthing App and directly go to my file manager app. I see for about 10 seconds (if I’m fast getting there after bootup) the mtime is still correct and then - poof - it is the “original mtime +4 hours” magically.

I suspect this is some Android OS service doing anything to it, but I’m currently trying to find out which one it might be. Btw I ran the tests on SDCARDFS (which is used in Android 8+) - here using an emulator with the recent Android 10 image from Google.

What makes me double confused is, when I hit the “override change” button on PC and the phone is “sendreceive”, I get the original timestamp back and then - magically - it stays like this even after reboot.

EDIT: This even occurs if the Syncthing app is NOT used and can be reproduced.

Here’s a good reproducer for the “sdcardfs - Android OS modifies mtime after reboot silently” problem:

• push a test file to phone using

adb push baseconv2.exe /storage/10F1-1918/Android/data/com.github.catfriend1.syncthingandroid.debug/files/baseconv2.exe

• Open your favorite file manager app and note the mtime (which is “original”)
• Reboot phone.
• Open your favorite file manager app and note the mtime has CHANGED silently (without running Syncthing) and is now “+4 hours”

New test scenario - without the Syncthing App:

• Disabled system app “Media storage” (Media Scanner?)
• adb push’ing test file … original mtime is there
• Rebooted phone.
• mtime changed, very suprising is, that the mtime now changed to “now - 2 hours” instead of “original + 4 hours”.

Damn! It’s even done by Android OS in the SDCARD root folder, see logs:

+0000  1836  1836 D vold    : Recognized experimental block major ID 253 as virtio-blk (emulator's virtual SD card device)
+0000  1836  1836 D vold    : /dev/block/vold/disk:253,80: LABEL="SDCARD" UUID="10F1-1918" TYPE="vfat"
+0000  1836  1836 D vold    : /dev/block/vold/public:253,80: LABEL="SDCARD" UUID="10F1-1918" TYPE="vfat"
+0000  1836  1836 D vold    : /system/bin/fsck_msdos
+0000  2654  2654 W sdcard  : Device explicitly enabled sdcardfs

adb shell ls /storage/10F1-1918 -l
-rwxrwx--x 1 root sdcard_rw 104960 1995-10-14 17:51 baseconv2.exe

+0000  4969  5729 I SDCardScannerService: getExternalFilesDirs /storage/emulated/0/Android/data/org.fdroid.fdroid/files
+0000  4969  5729 I SDCardScannerService: getExternalFilesDirs /storage/emulated/0/Android/data/org.fdroid.fdroid/files
+0000  4969  5729 I SDCardScannerService: getExternalFilesDirs /storage/10F1-1918/Android/data/org.fdroid.fdroid/files
+0000  4969  5729 I SDCardScannerService: getExternalFilesDirs /storage/10F1-1918/Android/data/org.fdroid.fdroid/files
+0000  4969  5729 I SDCardScannerService: sdcard files []

adb shell ls /storage/10F1-1918 -l
-rwxrwx--x 1 root sdcard_rw 104960 1995-10-14 21:51 baseconv2.exe

Tried to workaround by creating the .nomedia file in the test folders on the phone - no luck, mtime still being changed shortly after reboot when sdcard is mounted by android.

[AudriusButkevicius]

I am not sure if emulator is a sensible test bed, as things that provide time (bios etc) are emulated, so time can go anywhere it wants as it reboots.

[Catfriend1]

Huh… Nice Point, I’ll do more tests as I find real devices

[Catfriend1]

Wow, good work! It is indeed solved according to my most recent test on a Motorola X Play (lux) running on Android 8.0 (LineAgeOS without root).

I noticed one problem, as @rahrah said , the file system auto-detection doesn’t work properly on Android 8.0 (I mean the tested device with this).

Immediately on startup, even before the “Syncthing version XX” line comes up, it logs this:

DEBUG: Detecting FS at /storage/D9D0-1BFD/Android/media/com.github.catfriend1.syncthingandroid.debug/extsdtest on android, found , thus leaving mtime window at 0

If this is not a problem with PR #5852 's code, I suggest setting mtimeWindow to 2 secs from the wrapper. Tested this and it worked fine. I also learned that the problem only can be reproduced with a REAL device using SDCARD and syncing a file with an UNEVEN-second timestamp to it.

[Catfriend1]

Just to update the topic in case someone finds it via Google: The mtime bug on sdcardfs (FAT file systems) is fixed since v1.2.2-rc3

[rahrah (Richard)]

Yes, it’s most definitely fixed for me. Big THANK YOU to all for all the hard work and patience with this!

[MartinX3]

Luckily I searched today about the issue state, since the changelog wasn’t clearly describing that the fat32 mtime issue got fixed, in my opinion.

Now I seems can happily thank you for resolving this issue. <3