tree a7443a8a31257e585f88bbd9b1367ccf89d9484b
parent 019d5163cc5de0070db177e7fbd8f303abec6179
author Eric Biggers <ebiggers@google.com> 1602806078 -0700
committer Eric Biggers <ebiggers@google.com> 1602806176 -0700

IdleMaint: skip swap space, bind mounts, and virtual filesystems

When the idle maintenance task runs on Cuttlefish, there are several
warnings printed to logcat after the expected messages:

    D vold    : Starting trim of /data
    I vold    : Trimmed 0 bytes on /data in 36ms
    D vold    : Starting trim of /cache
    I vold    : Trimmed 58662912 bytes on /cache in 0ms
    D vold    : Starting trim of /metadata
    I vold    : Trimmed 7725056 bytes on /metadata in 12ms
    D vold    : Starting trim of none
    W vold    : Failed to open none: No such file or directory
    D vold    : Starting trim of /sdcard
    W vold    : Failed to open /sdcard: Not a directory
    D vold    : Starting trim of /mnt/vendor/shared
    W vold    : Trim failed on /mnt/vendor/shared: Inappropriate ioctl for device

This is because vold gathers the filesystems to trim from the fstab, but
it fails to exclude some entries that aren't appropriate to trim:

    /dev/block/zram0 none swap defaults zramsize=75%
    /tmp /sdcard none defaults,bind recoveryonly
    shared /mnt/vendor/shared virtiofs nosuid,nodev,noatime nofail

These should be excluded because they are swap space, a bind mount, and
a virtual filesystem respectively.

Fix addFromFstab() to exclude the above cases.

Afterwards, the messages on Cuttlefish are:

    D vold    : Starting trim of /data
    I vold    : Trimmed 0 bytes on /data in 39ms
    D vold    : Starting trim of /cache
    I vold    : Trimmed 58662912 bytes on /cache in 0ms
    D vold    : Starting trim of /metadata
    I vold    : Trimmed 9822208 bytes on /metadata in 12ms

Change-Id: Idc575106fe6f81c737f684429d58dba4bd5478ad