Dirent.FullName takes the global renameMu, but can be called during Create,
which itself takes dirent.mu and dirent.dirMu, which is a lock-order violation:
Dirent.Create
d.dirMu.Lock
d.mu.Lock
Inode.Create
gofer.inodeOperations.Create
gofer.NewFile
Dirent.FullName
d.renameMu.RLock
We only use the FullName here for logging, and in this case we can get by with
logging only the BaseName.
A `BaseName` method was added to Dirent, which simply returns the name, taking
d.parent.mu as required.
In the Create pathway, we can't call d.BaseName() because taking d.parent.mu
after d.mu violates the lock order. But we already know the base name of the
file we just created, so that's OK.
In the Open/GetFile pathway, we are free to call d.BaseName() because the other
dirent locks are not held.
PiperOrigin-RevId: 205112278
Change-Id: Ib45c734081aecc9b225249a65fa8093eb4995f10
The new policy is identical to FSCACHE (which caches everything in memory), but
it also flushes writes to the backing fs agent immediately.
All gofer cache policy decisions have been moved into the cachePolicy type.
Previously they were sprinkled around the codebase.
There are many different things that we cache (page cache, negative dirents,
dirent LRU, unstable attrs, readdir results....), and I don't think we should
have individual flags to control each of these. Instead, we should have a few
high-level cache policies that are consistent and useful to users. This
refactoring makes it easy to add more such policies.
PiperOrigin-RevId: 201206937
Change-Id: I6e225c382b2e5e1b0ad4ccf8ca229873f4cd389d
Nicolas Lacasse
Fabricio Voznika
Googler