Previously, an overlay would panic if either the upper or lower fs required
revalidation for a given Dirent. Now, we allow revalidation from the upper
file, but not the lower.
If a cached overlay inode does need revalidation (because the upper needs
revalidation), then the entire overlay Inode will be discarded and a new
overlay Inode will be built with a fresh copy of the upper file.
As a side effect of this change, Revalidate must take an Inode instead of a
Dirent, since an overlay needs to revalidate individual Inodes.
PiperOrigin-RevId: 208293638
Change-Id: Ic8f8d1ffdc09114721745661a09522b54420c5f1
When copying-up files from a lower fs to an upper, we also copy the extended
attributes on the file. If there is a (nested) overlay inside the lower, some
of these extended attributes configure the lower overlay, and should not be
copied-up to the upper.
In particular, whiteout attributes in the lower fs overlay should not be
copied-up, since the upper fs may actually contain the file.
PiperOrigin-RevId: 206236010
Change-Id: Ia0454ac7b99d0e11383f732a529cb195ed364062
Boot loader tries to stat mount to determine whether it's a file or not. This
may file if the sandbox process doesn't have access to the file. Instead, add
overlay on top of file, which is better anyway since we don't want to propagate
changes to the host.
PiperOrigin-RevId: 200411261
Change-Id: I14222410e8bc00ed037b779a1883d503843ffebb