There was a very bare get/setxattr in the InodeOperations interface. Add
context.Context to both, size to getxattr, and flags to setxattr.
Note that extended attributes are passed around as strings in this
implementation, so size is automatically encoded into the value. Size is
added in getxattr so that implementations can return ERANGE if a value is larger
than can fit in the user-allocated buffer. This prevents us from unnecessarily
passing around an arbitrarily large xattr when the user buffer is actually too
small.
Don't use the existing xattrwalk and xattrcreate messages and define our
own, mainly for the sake of simplicity.
Extended attributes will be implemented in future commits.
PiperOrigin-RevId: 290121300
These comments provided nothing, and have been copy-pasted into all
implementations. The code is clear without them.
I considered also removing the "handle implements handler.handle" comments, but
will let those stay for now.
PiperOrigin-RevId: 285876428
Note that the Sentry still calls Truncate() on the file before calling Open.
A new p9 version check was added to ensure that the p9 server can handle the
the OpenTruncate flag. If not, then the flag is stripped before sending.
PiperOrigin-RevId: 281609112
Currently, the path tracking in the gofer involves an O(n) lookup of
child fidRefs. This causes a significant overhead on unlinks in
directories with lots of child fidRefs (<4k).
In this transition, pathNode moves from sync.Map to normal synchronized
maps. There is a small chance of contention in walk, but the lock is
held for a very short time (and sync.Map also had a chance of requiring
locking).
OTOH, sync.Map makes it very difficult to add a fidRef reverse map.
PiperOrigin-RevId: 254489952
Neither fidRefs or children are (directly) synchronized by mu. Remove
the preconditions that say so.
That said, the surrounding does enforce some synchronization guarantees
(e.g., fidRef.renameChildTo does not atomically replace the child in the
maps). I've tried to note the need for callers to do this
synchronization.
I've also renamed the maps to what are (IMO) clearer names. As is, it is
not obvious that pathNode.fidRefs is a map of *child* fidRefs rather
than self fidRefs.
PiperOrigin-RevId: 254446965
The backing 9p server must allow named pipe creation, which the runsc
fsgofer currently does not.
There are small changes to the overlay here. GetFile may block when
opening a named pipe, which can cause a deadlock:
1. open(O_RDONLY) -> copyMu.Lock() -> GetFile()
2. open(O_WRONLY) -> copyMu.Lock() -> Deadlock
A named pipe usable for writing must already be on the upper filesystem,
but we are still taking copyMu for write when checking for upper. That
can be changed to a read lock to fix the common case.
However, a named pipe on the lower filesystem would still deadlock in
open(O_WRONLY) when it tries to actually perform copy up (which would
simply return EINVAL). Move the copy up type check before taking copyMu
for write to avoid this.
p9 must be modified, as it was incorrectly removing the file mode when
sending messages on the wire.
PiperOrigin-RevId: 249154033
Change-Id: Id6637130e567b03758130eb6c7cdbc976384b7d6
Based on the guidelines at
https://opensource.google.com/docs/releasing/authors/.
1. $ rg -l "Google LLC" | xargs sed -i 's/Google LLC.*/The gVisor Authors./'
2. Manual fixup of "Google Inc" references.
3. Add AUTHORS file. Authors may request to be added to this file.
4. Point netstack AUTHORS to gVisor AUTHORS. Drop CONTRIBUTORS.
Fixes#209
PiperOrigin-RevId: 245823212
Change-Id: I64530b24ad021a7d683137459cafc510f5ee1de9
This change also adds extensive testing to the p9 package via mocks. The sanity
checks and type checks are moved from the gofer into the core package, where
they can be more easily validated.
PiperOrigin-RevId: 218296768
Change-Id: I4fc3c326e7bf1e0e140a454cbacbcc6fd617ab55
Dean Deng
Nicolas Lacasse
Adin Scannell
Michael Pratt
Fabricio Voznika
Jamie Liu
Googler
Ian Gudger