[Galaxy S II Q&A, Help & Troubleshooting] cmonty14:
Hello!

I have put a MicroSD card in the device that I formatted with Ext4 with my PC in advance.

On the MicroSD card I copied > 10GB of data.

The MicroSD is mounted correctly in /storage/sdcard1:

user@pc1-gigabyte:~$ adb shell mount
rootfs / rootfs ro,relatime 0 0
tmpfs /dev tmpfs rw,seclabel,nosuid,relatime,mode=755 0 0
devpts /dev/pts devpts rw,seclabel,relatime,mode=600 0 0
proc /proc proc rw,relatime 0 0
sysfs /sys sysfs rw,seclabel,relatime 0 0
selinuxfs /sys/fs/selinux selinuxfs rw,relatime 0 0
none /acct cgroup rw,relatime,cpuacct 0 0
none /sys/fs/cgroup tmpfs rw,seclabel,relatime,mode=750,gid=1000 0 0
tmpfs /mnt/asec tmpfs rw,seclabel,relatime,mode=755,gid=1000 0 0
tmpfs /mnt/obb tmpfs rw,seclabel,relatime,mode=755,gid=1000 0 0
none /dev/cpuctl cgroup rw,relatime,cpu 0 0
/dev/block/mmcblk0p9 /system ext4 ro,seclabel,noatime,user_xattr,barrier=1,data=ordered 0 0
/dev/block/mmcblk0p7 /cache ext4 rw,seclabel,nosuid,nodev,noatime,errors=panic,user_xattr,barrier=1,journal_async_commit,data=ordered 0 0
/dev/block/mmcblk0p1 /efs ext4 rw,seclabel,nosuid,nodev,noatime,errors=panic,user_xattr,barrier=1,journal_async_commit,data=ordered 0 0
/dev/block/mmcblk0p10 /data ext4 rw,seclabel,nosuid,nodev,noatime,errors=panic,user_xattr,barrier=1,journal_async_commit,data=ordered,noauto_da_alloc 0 0
/dev/block/mmcblk0p12 /preload ext4 rw,seclabel,nosuid,nodev,noatime,user_xattr,barrier=1,journal_async_commit,data=ordered 0 0
/sys/kernel/debug /sys/kernel/debug debugfs rw,relatime 0 0
/dev/block/vold/259:3 /mnt/media_rw/sdcard0 vfat rw,dirsync,nosuid,nodev,noexec,relatime,uid=1023,gid=1023,fmask=0007,dmask=0007,allow_utime=0020,codepage=cp437,iocharset=iso8859-1,shortname=mixed,utf8,errors=remount-ro 0 0
/dev/block/vold/259:3 /mnt/secure/asec vfat rw,dirsync,nosuid,nodev,noexec,relatime,uid=1023,gid=1023,fmask=0007,dmask=0007,allow_utime=0020,codepage=cp437,iocharset=iso8859-1,shortname=mixed,utf8,errors=remount-ro 0 0
/dev/fuse /storage/sdcard0 fuse rw,nosuid,nodev,noexec,relatime,user_id=1023,group_id=1023,default_permissions,allow_other 0 0
/dev/block/vold/179:9 /mnt/media_rw/sdcard1 ext4 rw,dirsync,context=u:object_r:sdcard_posix:s0,nosuid,nodev,noexec,noatime,user_xattr,barrier=1,data=ordered 0 0
/dev/block/vold/179:9 /mnt/secure/asec ext4 rw,dirsync,context=u:object_r:sdcard_posix:s0,nosuid,nodev,noexec,noatime,user_xattr,barrier=1,data=ordered 0 0
/dev/block/vold/179:9 /mnt/media_rw/sdcard0/.android_secure ext4 rw,dirsync,context=u:object_r:sdcard_posix:s0,nosuid,nodev,noexec,noatime,user_xattr,barrier=1,data=ordered 0 0
/dev/fuse /storage/sdcard1 fuse rw,nosuid,nodev,noexec,relatime,user_id=1023,group_id=1023,default_permissions,allow_other 0 0

Checking the user and group permissions they are equal for /storage/sdcard0 and /storage/sdcard1:

user@pc1-gigabyte:~$ adb shell ls -l /storage
drwxrwx--x root sdcard_r 2015-08-08 14:33 sdcard0
drwxrwx--x root sdcard_r 2015-08-06 20:27 sdcard1
drwxrwx--- root root 2015-08-08 11:36 usbdisk0

This is also true for any file / directory stored in /storage/sdcard1:

thomas@pc1-gigabyte:~$ adb shell ls -l /storage/sdcard1
drwxrwx--x root sdcard_r 2015-03-28 16:11 Android
drwxrwx--- root sdcard_r 2015-08-05 17:41 DCIM
drwxrwx--- root sdcard_r 2015-08-06 02:13 TWRP
drwxrwx--- root sdcard_r 2015-08-05 10:34 TitaniumBackup
drwxrwx--- root sdcard_r 2015-03-28 16:11 audio
drwxrwx--- root sdcard_r 2015-08-04 17:10 backup
drwxrwx--- root sdcard_r 2015-03-28 16:12 bilder
drwxrwx--- root sdcard_r 2015-04-23 16:40 brouter
drwxrwx--- root sdcard_r 2015-05-21 14:43 clockworkmod
drwxrwx--- root sdcard_r 2015-03-28 16:17 data
drwxrwx--- root sdcard_r 2015-03-28 16:19 documents
drwxrwx--- root sdcard_r 2015-08-05 22:55 download
drwxrwx--- root sdcard_r 2015-05-31 22:02 keepass
drwxrwx--- root sdcard_r 2015-08-05 22:16 lost+found
drwxrwx--- root sdcard_r 2015-03-28 16:27 musik
drwxrwx--- root sdcard_r 2015-08-03 20:49 oruxmaps
drwxrwx--- root sdcard_r 2015-03-28 16:29 video
-rw-rw---- root sdcard_r 307873 2015-08-08 16:20 xposed-uninstaller-arm.zip
-rw-rw---- root sdcard_r 3540968 2015-08-08 16:20 xposed-v69-sdk22-arm-by-romracer-20150804.zip

However, I cannot write any file to /storage/sdcard1/<subdirectory>:

shell@GT-I9100:/storage/sdcard1 $ cp -v xposed-* backup/
cp: backup/xposed-uninstaller-arm.zip: Permission denied
cp: backup/xposed-v69-sdk22-arm-by-romracer-20150804.zip: Permission denied

Question:

Why is any subdirecty in /storage/sdcard1 with read-only permission?

THX