Commit Graph

96 Commits

Author SHA1 Message Date
Chad Austin
bfc189cc92 Use a deterministic executor in TestMount
Summary:
As a prerequisite to running inode unloading code in a background
queue, use a deterministic executor in TestMount to make sequencing in
unit tests reliable.

Reviewed By: simpkins

Differential Revision: D9323878

fbshipit-source-id: 0b85632c1637a8cf83d6f238675e5b6bbb6923c7
2018-08-21 12:23:00 -07:00
Chad Austin
8b4841ef82 Replace shared_ptr<JournalDelta> with a custom intrusive JournalDeltaPtr
Summary:
For O(1) stack space JournalDelta destruction, we need to check
whether a reference-counted pointer has a unique refcount. It looks at
first glance like shared_ptr<T>::unique() gives us that, but it uses a
relaxed load and is now deprecated.

Sadly, the easiest thing is to make a new smart pointer class. (It
happens to be slightly more efficient, requiring one fewer heap
allocation per entry in the chain.)

Reviewed By: simpkins

Differential Revision: D9355314

fbshipit-source-id: 8c782ba9e0ec27fae90325079c199e1b82df88fa
2018-08-17 21:06:53 -07:00
Chad Austin
5d54a799c9 Rename UnboundedQueueThreadPool to UnboundedQueueExecutor and add a ManualExecutor variant
Summary:
To improve the determinism of our C++ tests, I am planning to switch
TestMount to a ManualExecutor. This adds a ManualExecutor constructor
to UnboundedQueueExecutor.

In Rust, I'd use a trait, but a simple class with two constructors works fine.

Reviewed By: strager

Differential Revision: D8846553

fbshipit-source-id: c52752105255503d26f1e65494c32b3f62882e44
2018-08-03 13:21:59 -07:00
Chad Austin
51ed99000d Remove the redundant path_ member of EdenMount
Summary:
While trying to make destroyWithInitRace non-flaky, it uncovered an
ASAN violation in the case that fuseCompleteFuture finishes during
EdenMount destruction. In that case, path_ gets destroyed prior to the
executor, so it's illegal to construct TakeoverData::MountInfo from
path_. This diff removes path_ entirely and reads it from
ClientConfig.

Reviewed By: simpkins, strager

Differential Revision: D8848663

fbshipit-source-id: f9368aa9eec7dfa8f2897cce55fad6d19723e30c
2018-07-16 13:52:01 -07:00
Adam Simpkins
5305edefc1 update PrivHelper APIs to return Futures
Summary:
Up until now all of the privhelper APIs have been blocking calls.  This
changes the privhelper functions to return Futures, and updates all users of
these APIs to be able to handle the results using Futures.

One benefit of this change is that all existing mount points are remounted in
parallel now during startup, rather than being mounted serially.  The old code
performed a blocking `get()` call on the future returned by
`EdenServer::mount()`.

The privhelper calls themselves are still blocking for now--they block until
complete and always return completed Future objects.  I will update the
privhelper code in a subsequent diff to actually make it asynchronous.

Reviewed By: bolinfest

Differential Revision: D8053421

fbshipit-source-id: 342d38697f67518f6ca96a37c12dd9812ddb151d
2018-06-11 18:32:25 -07:00
Chad Austin
d4e186f995 store FileInode and TreeInode timestamps in the InodeTable
Summary: Store tree and file timestamps in the InodeTable so they persist across runs.

Reviewed By: simpkins

Differential Revision: D6891479

fbshipit-source-id: 1c9e6266375aceeaf293a81e73cf7f5334dbc32d
2018-05-22 11:22:19 -07:00
Adam Simpkins
8e3c09a99a move folly/experimental/logging to folly/logging/
Summary:
Promote the folly logging code out of the experimental subdirectory.
We have been using this for several months in a few projects and are pretty
happy with it so far.

After moving it out of the experimental/ subdirectory I plan to update
folly::Init() to automatically support configuring it via a `--logging` command
line flag (similar to the initialization it already does today for glog).

Reviewed By: yfeldblum, chadaustin

Differential Revision: D7755455

fbshipit-source-id: 052db34c97f7516728f7cbb1a5ad959def2f6efb
2018-04-30 21:29:29 -07:00
Chad Austin
c22dd7924d mark a bunch of folly::Future<folly::Unit> functions with FOLLY_NODISCARD
Summary:
To avoid bugs similar to the ones fixed in D7781691, mark a bunch of
folly::Future<folly::Unit> functions with FOLLY_NODISCARD.

Reviewed By: simpkins

Differential Revision: D7782224

fbshipit-source-id: 23ba42aa63011cc33e5a6e18d5bc6d00403a78d3
2018-04-26 21:00:25 -07:00
Chad Austin
45c33d5cfd Lock down access to the .eden directory after mount startup
Summary:
Disallow any kind of mutation operation inside of the .eden directory.  We had some
code in place to prevent some of this already, but errors (including EPERM) weren't
passed out from unlink and rename out to FUSE.

Reviewed By: simpkins

Differential Revision: D7781691

fbshipit-source-id: aaecf13779eca75d6ee8765fc8bb3727ce9341de
2018-04-26 21:00:25 -07:00
Adam Simpkins
0195e0f6f0 ensure that the ServerState object outlives all EdenMounts
Summary:
This updates the code to store ServerState using a shared_ptr rather than
having it be an inlined member variable of EdenServer.

Previously EdenMount objects contained a raw pointer to the ServerState, with
the reasoning that the EdenServer object should outlive the EdenMount objects.
It turns out that this is not quite true in practice--EdenMount::destroy() will
normally be called before the EdenServer is destroyed, but this may not
actually destroy the EdenMount object immediately.

This fixes a race condition in the FuseTest.initMount() test that could cause
this test to occasionally fail when run on a heavily loaded system.

Reviewed By: chadaustin

Differential Revision: D7720509

fbshipit-source-id: 056ff5985587c8d8c32c11d17ba637ebd7598677
2018-04-23 13:53:48 -07:00
Adam Simpkins
645731a8a0 release the overlay lock when EdenMount::shutdown() completes
Summary:
Change EdenMount to destroy the Overlay object as soon as the `shutdown()`
operation completes.  Previously the Overlay would not get destroyed until
EdenMount::destroy() was called.

During graceful restart we transfer mount information to the new process after
`shutdown()` completes, but potentially before `destroy()` has finished.  This
previously resulted in a race condition where the new process could start
opening the overlay before the old process had released the lock.  This change
should fix that race condition.

Reviewed By: chadaustin

Differential Revision: D7543295

fbshipit-source-id: 82ae33fe6bb0aa9f0a3b010fdd1d350c63442420
2018-04-09 12:21:03 -07:00
Adam Simpkins
7c2d0b13b1 store the Overlay using unique_ptr rather than shared_ptr
Summary: Each Overlay object should be owned only by its EdenMount.

Reviewed By: chadaustin

Differential Revision: D7543294

fbshipit-source-id: 6db40fea31ce298c61d047cba9165887e32926a1
2018-04-09 12:21:03 -07:00
Adam Simpkins
2fedc3bcea update getScmStatus() to require the commit hash as an argument
Summary:
Change getScmStatus() so that callers must explicitly specify the commit to
diff against.  This should help avoid race conditions around commit or checkout
operations where the parent commit has just changed and eden returns status
information against a commit that wasn't what the client was expecting.

This should still maintain backwards compatibility with older clients that do
not send this parameter yet: we will simply receive the hash as an empty string
in this case, and we still provide the old behavior in this case.

Reviewed By: wez

Differential Revision: D7512338

fbshipit-source-id: 1fb4645dda13b9108c66c2daaa802ea3445ac5f2
2018-04-06 12:51:31 -07:00
Chad Austin
f80dd19454 add a graceful takeover method to TestMount
Summary: Now we can write unit tests for takeover. :)

Reviewed By: simpkins

Differential Revision: D7345419

fbshipit-source-id: 05741dab65016c59109bf190c83be2f676a6141d
2018-03-23 15:06:22 -07:00
Adam Simpkins
685077677e update getScmStatusBetweenRevisions() to avoid creating inode objects
Summary:
Update the getScmStatusBetweenRevisions() thrift call to use the new
diffCommits() function that diffs source control Tree objects without creating
TreeInode objects to perform the diff.

This addresses two bugs:
- Each call to EdenMount::diffRevisions() constructed a new root inode
  associated with the mount, and this would never get destroyed.  It was not
  destroyed at the end of the diffRevisions() call since inodes are normally
  not destroyed immediately when they are unreferenced.  It was not destroyed
  during EdenMount::shutdown() since EdenMount didn't have any references to
  these additional root inode structures and their children.
- EdenMount::diffRevisions() incorrectly swapped ADDED and REMOVED statuses in
  the result.

Reviewed By: wez

Differential Revision: D7341609

fbshipit-source-id: 16e755a0ff685f51c977c3b27d6af96908f33494
2018-03-20 16:47:12 -07:00
Adam Simpkins
bfcf4c574a remove the fusell namespace
Summary: Move everything in the `facebook::eden::fusell` namespace to `facebook::eden`

Reviewed By: chadaustin

Differential Revision: D7314458

fbshipit-source-id: db56d3e5fb898235e1376ac76077cf780d9b4698
2018-03-19 17:01:52 -07:00
Adam Simpkins
8eff641bf3 prevent FuseChannel from being destroyed with outstanding requests
Summary:
The FuseChannel destructor previously could be invoked while there are still
outstanding requests, which would cause problems when responses were generated
for these requests.

This makes the FuseChannel destructor private, requiring users to always
allocate FuseChannel objects on the heap and destroy them using a destroy()
method.  The destroy() method still blocks waiting for the FUSE worker threads
to exit, but if there are still outstanding FUSE requests it defers the
deletion of the FuseChannel until they are complete.

The EdenMount class currently couldn't ever destroy FuseChannel objects with
outstanding requests, since it waits for the completion future to fire before
invoking the destructor.  Fixing this behavior is mostly for correctness of the
FuseChannel API and for the benefit of our unit tests.

Reviewed By: chadaustin

Differential Revision: D7297829

fbshipit-source-id: 643d1332be84a1f25ee30ba2a2ea3515806f00ef
2018-03-16 12:35:19 -07:00
Adam Simpkins
ac35979de3 move the clock to ServerState
Summary:
Make ServerState also store the clock as a member variable.  This moves more
server-wide state into the ServerState class, and allows us to eliminate
another argument to the EdenMount constructor.

Reviewed By: chadaustin

Differential Revision: D7297832

fbshipit-source-id: 2a063d67752f46686987390b3faefb304455568a
2018-03-16 12:35:19 -07:00
Adam Simpkins
89b0607f0f move the main thread pool to ServerState
Summary:
Move the EdenCPUThreadPool from EdenServer to ServerState.

This ensures that all EdenMount objects always have a thread pool.  Previously
most unit tests were creating an EdenMount without a thread pool set, but the
FileInode code and TreeInode code could end up wanting to use the thread pool
even if no FuseChannel is running.

Reviewed By: chadaustin

Differential Revision: D7297828

fbshipit-source-id: 9861b3439cd091afe31fa13f449aa14656983318
2018-03-16 12:35:19 -07:00
Adam Simpkins
c5f4ea6f8b update FuseChannel::initialize() to return the completion future
Summary:
Remove the `FuseChannel::getSessionCompleteFuture()` method and instead have
`initialize()` and `initializeFromTakeover()` return the `Future` that can be
used to wait on session completion.

This makes it explicit from an API perspective that this session completion
future will only be invoked if initialization is successful.  It also
eliminates the possibility of anyone calling getSessionCompleteFuture() more
than once.

I also changed the session completion future to use a folly::SemiFuture rather
than a folly::Future, to make it explicit that callers generally should not
execute their callback inline in the same thread where the SemiFuture is
fulfilled.

Reviewed By: chadaustin

Differential Revision: D7297835

fbshipit-source-id: 3a1157951f0738f1692833ed5e875c3e9c6d6d69
2018-03-16 12:35:19 -07:00
Chad Austin
053bec97ac Eliminate InodeMap::load and require that the takeover state be passed into initialize
Summary: Cleaning up the takeover initialization code for EdenMount and InodeMap.

Reviewed By: simpkins

Differential Revision: D7294419

fbshipit-source-id: 58506f04259bb1017e6cd2e80e40e5820de6200f
2018-03-15 17:48:27 -07:00
Chad Austin
20dc41871b Make it clearer that SerializedInodeMap is a byproduct of takeover shutdown
Summary:
Instead of having a rule that save() must be called after
InodeMap::shutdown, just have InodeMap::shutdown return the
SerializedInodeMap if it's desired.

Reviewed By: simpkins

Differential Revision: D7292773

fbshipit-source-id: 2ba35fc729e19af122fe5d6c5a3287ad6b8af946
2018-03-15 17:48:27 -07:00
Adam Simpkins
1b441aa0b4 split up FUSE initialization for fresh start vs takeover
Summary:
Split up the FuseChannel and EdenMount APIs for starting a brand new FUSE
channel vs taking over an existing channel.

These operations are somewhat different as initializing a new FUSE channel
requires performing a negotiation with the kernel that will not complete
immediately.  Therefore these APIs return a Future object.  Taking over an
existing FUSE channel is always an immediate operation, and therefor does not
need to return a Future object.

Reviewed By: chadaustin

Differential Revision: D7241997

fbshipit-source-id: 22780f2df76b2d554ab2a4043b6425fa7a4e9c94
2018-03-12 21:28:50 -07:00
Chad Austin
ab39bcc10f decouple inode allocation initialization from the rest of InodeMap
Summary:
If the root TreeInode wants to allocate inode numbers, the inode
allocator must be initialized first.  But complete InodeMap
initialization requires the root TreeInode.  So split this into two
parts.

Also, I changed the inode allocator to a single atomic increment instead
of a lock acquisiton.

Finally, the extra assertions in this diff uncovered what looks like a
bug in the takeover logic where nextInodeNumber_ could end up being
smaller than the value in the takeover data, since the max inode
number from the overlay was assigned after loading from takeover data.

Reviewed By: simpkins

Differential Revision: D7107706

fbshipit-source-id: ec43cc81c11d709261598739c622609b372433a2
2018-03-07 23:11:49 -08:00
Chad Austin
34f78baa21 make it annoying to use InodeNumber as an integer
Summary:
I'm seeing test failures that I have not yet understood and I
thought they might be caused by an implicit conversion from
fusell::InodeNumber to bool.  Well, they're not, but this is how I
discovered that.  I'm not sure I want to land this change, but I'm
going to leave it around until I figure out what's happening with my
other diffs.

Reviewed By: simpkins

Differential Revision: D7077635

fbshipit-source-id: 50bf67026d2d0da0220c4709e3db24d841960f4b
2018-02-27 12:44:41 -08:00
Adam Simpkins
bc93fd13b6 update diff code to use previously retrieved UserInfo
Summary:
Update EdenMount::diff() to use the UserInfo object stored in the shared
ServerState rather than calling UserInfo::lookup() on each diff operation.

Reviewed By: wez

Differential Revision: D6929865

fbshipit-source-id: a68ab1fa9eb345b59972e67c3aac258b4dbcdab5
2018-02-08 19:36:03 -08:00
Adam Simpkins
265b17d188 add a new ServerState class to store process-wide state
Summary:
Add a new ServerState class to store process-wide state that is shared across
multiple mounts.  Up until now we have passed around the shared state data as
separate variables.

This is intentionally separate from the existing EdenServer class to allow unit
tests to create EdenMount objects without an EdenServer object.

Reviewed By: wez

Differential Revision: D6929861

fbshipit-source-id: 5f22efb6d79dfd70031be1dc37f494c2ad8af902
2018-02-08 16:43:22 -08:00
Wez Furlong
2e660e0d45 remove FuseChannel::threadsStoppingFuture
Summary:
We no longer need this and I believe that this was contributing
to this source of flakiness in our CI; this stack trace triggers when
we get an aborted or short read from the kernel:

```
*** Aborted at 1517827659 (Unix time, try 'date -d 1517827659') ***
*** Signal 11 (SIGSEGV) (0x2d0) received by PID 153706 (pthread TID 0x7f63ea37d700) (linux TID 160573) (maybe from PID 720, UID 0) (code: address not mapped to object), stack trace: ***
    @ 0000000002abfa2d folly::symbolizer::(anonymous namespace)::signalHandler(int, siginfo_t*, void*)
                       ./folly/experimental/symbolizer/SignalHandler.cpp:413
    @ 00007f646e96dacf (unknown)
    @ 00007f646e96aa20 __pthread_kill
    @ 0000000001873748 facebook::eden::fusell::FuseChannel::requestSessionExit()
                       ./eden/fs/fuse/FuseChannel.cpp:483
    @ 000000000187d2f7 facebook::eden::fusell::FuseChannel::processSession()
                       ./eden/fs/fuse/FuseChannel.cpp:656
    @ 000000000187dab9 facebook::eden::fusell::FuseChannel::fuseWorkerThread(unsigned long)
                       ./eden/fs/fuse/FuseChannel.cpp:493
    @ 00007f646f267170 execute_native_thread_routine
    @ 00007f646e9637a8 start_thread
    @ 00007f646e047a7c __clone
```

my theory is that we're allowing shutdownImpl to free things out from under other
threads before they've all seen this signal and wound down fully.  This is slightly
speculative in that I haven't managed to reproduce this stack trace on my devserver.

We don't really need this additional signal any longer.

Reviewed By: simpkins

Differential Revision: D6907734

fbshipit-source-id: 0f0138b631a7201fc9a4a1c93c2cde846e869cbd
2018-02-07 17:36:11 -08:00
Adam Simpkins
00a232d868 make Clock::getRealtime() const
Summary: This API seems like it should be const, as it does not modify the clock.

Reviewed By: chadaustin, zhupanov

Differential Revision: D6869719

fbshipit-source-id: c8bf4ccab34538b59e6baeedd0b0ff88b328236e
2018-02-01 11:19:15 -08:00
Wez Furlong
89c0c2cb90 clean up fuse init processing
Summary:
This diff moves the mount-time initialization handling
out of the main loop.  This rationale for this is:

* We don't (and shouldn't!) need to process FUSE_INIT for takeover
  processing, and this structure allows us to make stronger assertions
  about our state.
* we can avoid spinning up multiple threads in the (rare!) case that
  the FUSE_INIT fails
* It is now a little harder for exceptions during initialization to
  escape our notice.

In rearranging this stuff, I found a race condition in the worker thread
shutdown; we could erroneously emit a completion event before all of
the threads had been torn down and this resulted in sporadic integration
test failures hitting the assertion for the number of joined threads
in the destructor.

Reviewed By: simpkins

Differential Revision: D6766330

fbshipit-source-id: 32afb5a7c739c75aebfdb0a8f896eec5f41ad33f
2018-01-31 15:08:42 -08:00
Wez Furlong
530346887d split EdenMount::{create,initialize} -> safer takeover mounting
Summary:
Previously, `EdenMount::create` would implicitly call
`EdenMount::initialize` which would load the root inode and the `.eden` magical
directory.  That's fine for the fresh mount case, but in the case of the
graceful restart we need to take the opportunity to apply the `InodeMap`
from the old process before we start muddying its state.

This diff breaks out the `initialize` method from the `create` method and
makes the mount code call it after potentially loading the `InodeMap` from
the takeover data.

In addition, this diff removes the the `root->loadMaterializedChildren()`
call from the mount initialization code.  It is no longer required to do
this eagerly and it makes things simpler and our memory profile a little
smaller to defer this (I haven't measured how much that impacts things).

Reviewed By: simpkins

Differential Revision: D6691182

fbshipit-source-id: 52033a6d64105b658314a919f69dbfcd4eea242b
2018-01-10 13:13:50 -08:00
Wez Furlong
014789b4ca open file handles now survive graceful restart
Summary:
I'm so-so on a bit of the implementation here, but it works!

I had to change the `takeoverPromise` from the `pair<fuseDevice, connInfo>`
to a new helper struct because we now have three distinct pieces of data
to pass out of EdenMount to build up the overall TakeoverData.

The key change in this diff is that we have to release all of the file handles
we're maintaining in the `FileHandleMap` prior to shutting down the `InodeMap`,
otherwise the `InodeMap` will never complete (it waits for all inodes to be
unreferenced, and that cannot happen while there are open file handles).  I've
made the `FileHandleMap` serialization and clearing contingent on performing a
takeover shutdown because that feels like the safest thing to do wrt. not
losing any pending writes.

Reviewed By: simpkins

Differential Revision: D6672437

fbshipit-source-id: 7b1f0f8e7ff09dbed850c7737383ecdf1e5ff0c7
2018-01-09 22:23:11 -08:00
Wez Furlong
490e6adcf5 inform PrivHelper of takeover; graceful restarts now work!
Summary:
This is the key portion that makes the graceful restart
function.  This diff connects almost all of the moving pieces together;
it informs the priv helper about the takeover mount and transfers
the InodeMap information into the new generation of the eden server.

It doesn't yet load the fileHandleMap (will tackle that in a follow up diff)

Reviewed By: simpkins

Differential Revision: D6670903

fbshipit-source-id: 1770d99eb1477440a6c1deed83b0da55b9c1bbe4
2018-01-09 22:23:10 -08:00
Wez Furlong
8689b37221 connect the fuse device information to the takeover data
Summary:
This adds some plumbing to thread the fuse device descriptor and
negotiated capabilities through to the takeover code.

I initially wanted to just make the
unmount future yield the device descriptor, but since that uses
`SharedPromise` it is not compatible with a move-only type like
`folly:File`, so I added an optional promise to deal with just that.

I'm also populating the takeover mount information (path, bind mounts)
for each mount point.

Reviewed By: simpkins

Differential Revision: D6494509

fbshipit-source-id: a90684292dc1d8e06ce2c0721eadd8d393377f33
2018-01-09 22:23:04 -08:00
Sergey Zhupanov
a3ef94a011 Added EdenMount::resolveSymlink(InodePtr pInode) with tests.
Summary: EdenMount::resolveSymlink(InodePtr pInode) resolves symlink to INodePtr.

Reviewed By: simpkins

Differential Revision: D6659644

fbshipit-source-id: 8be9ca06b08bf9730ff961e55c3ee747d5f45707
2018-01-05 15:35:42 -08:00
Wez Furlong
482d1a1aff move fuse thread pool to FuseChannel
Summary:
Now that we have full control over the fuse session,
moving the threads here makes a lot of sense and makes things
easier from an overall state management perspective.

FuseChannel now provides a future that make it easier for EdenMount to wait
until all the threads and outstanding requests have completed.

There is also a future to determine when the first of the threads
has exited which is used to detect an error condition.  We could
go a bit further with this and have the error condition propagate
out from our dispatcher, but that's a bit further away from my
goal of making the graceful restart stuff work.

I've removed the request counting stuff from Dispatcher as we
can now use the definitive signals from FuseChannel in its place.

Reviewed By: chadaustin

Differential Revision: D6580247

fbshipit-source-id: 6bcc3b8b531d59a3fdd0ca6fd09410ad64f8221a
2018-01-03 09:38:34 -08:00
Wez Furlong
6ff492d11c remove dep on libfuse
Summary:
This serves a few purposes:

1. We can avoid some conditional code inside eden if we know that
   we have a specific fuse_kernel.h header implementation.
2. We don't have to figure out a way to propagate the kernel
   capabilities through the graceful restart process.
3. libfuse3 removed the channel/session hooks that we've been
   using thus far to interject ourselves for mounting and
   graceful restarting, so we were already effectively the
   walking dead here.
4. We're now able to take advtange of the latest aspects of
   the fuse kernel interface without being tied to the implementation
   of libfuse2 or libfuse3.  We're interested in the readdirplus
   functionality and will look at enabling that in a future diff.

This may make some things slightly harder for the more immediate
macOS port but I belive that we're in a much better place overall.

This diff is relatively mechanical and sadly is (unavoidably) large.

The main aspects of this diff are:

1. The `fuse_ino_t` type was provided by libfuse so we needed to
   replace it with our own definition.  This has decent penetration
   throughout the codebase.
2. The confusing `fuse_file_info` type that was multi-purpose and
   had fields that were sometimes *in* parameters and sometimes *out*
   parameters has been removed and replaced with a simpler *flags*
   parameter that corresponds to the `open(2)` flags parameter.
   The *out* portions are subsumed by existing file handle metadata
   methods.
3. The fuse parameters returned from variations of the `LOOKUP` opcode
   now return the fuse kernel type for this directly.  I suspect
   that we may need to introduce a compatibility type when we revisit
   the macOS port, but this at least makes this diff slightly simpler.
   You'll notice that some field and symbol name prefixes vary as
   a result of this.
4. Similarly for `setattr`, libfuse separated the kernel data into
   two parameters that were a little awkward to use; we're now just
   passing the kernel data through and this, IMO, makes the interface
   slightly more understandable.
5. The bulk of the code from `Dispatcher.cpp` that shimmed the
   libfuse callbacks into the C++ virtual methods has been removed
   and replaced by a `switch` statement based dispatcher in
   `FuseChannel`.   I'm not married to this being `switch` based
   and may revise this to be driven by an `unordered_map` of
   opcode -> dispatcher method defined in `FuseChannel`.  Regardless,
   `Dispatcher.cpp` is now much slimmer and should be easier to
   replace by rolling it together into `EdenDispatcher.cpp` in
   the future should we desire to do so.
6. This diff disables dispatching `poll` and `ioctl` calls.  We
   didn't make use of them and their interfaces are a bit fiddly.
7. `INTERRUPT` is also disabled here.  I will re-enable it in
   a follow-up diff where I can also revise how we track outstanding
   requests for graceful shutdown.
8. I've imported `fuse_kernel.h` from libfuse.  This is included
   under the permissive 2-clause BSD license that it allows for
   exactly this integration purpose.

Reviewed By: simpkins

Differential Revision: D6576472

fbshipit-source-id: 7cb088af5e06fe27bf22a1bed295c18c17d8006c
2018-01-02 16:36:16 -08:00
Chad Austin
2f22a9f534 introduce a type representing the unbounded eden cpu pool
Summary:
Add EdenCPUThreadPool and UnboundedQueueThreadPool types to make it clearer
that it's always okay for prefetch, deferred diff entry, and hg import to
shuttle work back to the main thread pool.

This diff changes no behavior - it just makes some invariants explicit.

Reviewed By: wez, simpkins

Differential Revision: D6504117

fbshipit-source-id: 3400ad55c00b3719ecba31807fd992442f622cd9
2017-12-12 12:35:35 -08:00
Sergey Zhupanov
b6394ac357 Added user and general system level gitignore
Summary:
Added to Eden capability to incorporate default user and general system level gitignore files.
NOTE: Work in progress, sending the review out to calibrate/ensure I am on right track.

Reviewed By: simpkins

Differential Revision: D6482863

fbshipit-source-id: 9834ca1a577a9599a1f8cb2243dca4e714866be8
2017-12-08 12:52:51 -08:00
Chad Austin
d112d63870 remove all direct calls to clock_gettime and system_clock::now
Summary:
Follow-up to comments in D6466209.  All access to the clock goes
through the Clock interface, making time deterministic in unit tests.

Reviewed By: simpkins

Differential Revision: D6477973

fbshipit-source-id: 24e51bdb52d0d079b34d91598d2e787d361f2525
2017-12-05 10:06:50 -08:00
Chad Austin
f91ae520b2 introduce a Clock seam for testability
Summary:
Introduce a Clock seam.  This will allow us to write tests around
ctime, mtime, and atime logic.

Reviewed By: wez

Differential Revision: D6392543

fbshipit-source-id: 1721d76d2364b135b4ef5c078ef60f7f8526259e
2017-12-05 10:06:48 -08:00
Michael Bolin
5e2afa735f Change how the UNTRACKED_ADDED conflict and merges are handled.
Summary:
Previously, we used the Mercurial code `g` when faced with an `UNTRACKED_ADDED`
file conflict, but that was allowing merges to silently succeed that should not
have. This revision changes our logic to use the code `m` for merge, which
unearthed that we were not honoring the user's `update.check` setting properly.

Because we use `update.check=noconflict` internally at Facebook, we changed the
Eden integration tests to default to verifying Hg running with this setting. To
support it properly, we had to port this code from `update.py` in Mercurial to
our own `_determine_actions_for_conflicts()` function:

```
if updatecheck == 'noconflict':
    for f, (m, args, msg) in actionbyfile.iteritems():
        if m not in ('g', 'k', 'e', 'r', 'pr'):
            msg = _("conflicting changes")
            hint = _("commit or update --clean to discard changes")
            raise error.Abort(msg, hint=hint)
```

However, this introduced an interesting issue where the `checkOutRevision()`
Thrift call from Hg would update the `SNAPSHOT` file on the server, but
`.hg/dirstate` would not get updated with the new parents until the update
completed on the client. With the new call to `raise error.Abort` on the client,
we could get in a state where the `SNAPSHOT` file had the hash of the commit
assuming the update succeeded, but `.hg/dirstate` reflected the reality where it
failed.

To that end, we changed `checkOutRevision()` to take a new parameter,
`checkoutMode`, which can take on one of three values: `NORMAL`, `DRY_RUN`, and
`FORCE`. Now if the user tries to do an ordinary `hg update` with
`update.check=noconflict`, we first do a `DRY_RUN` and examine the potential
conflicts. Only if the conflicts should not block the update do we proceed with
a call to `checkOutRevision()` in `NORMAL` mode.

To make this work, we had to make a number of changes to `CheckoutAction`,
`CheckoutContext`, `EdenMount`, and `TreeInode` to keep track of the
`checkoutMode` and ensure that no changes are made to the working copy when a
`DRY_RUN` is in effect.

One minor issue (for which there is a `TODO`) is that a `DRY_RUN` will not
report any `DIRECTORY_NOT_EMPTY` conflicts that may exist. As `TreeInode` is
implemented today, it is a bit messy to report this type of conflict without
modifying the working copy along the way.

Finally, any `UNTRACKED_ADDED` conflict should cause an update to
abort to match the behavior in stock Mercurial if the user has the following
config setting:

```
[commands]
update.check = noconflict
```

Though the original name for this setting was:

```
[experimental]
updatecheck = noconflict
```

Although I am on Mercurial 4.4.1, the `update.check` setting does not seem to
take effect when I run the integration tests, but the `updatecheck` setting
does, so for now, I set both in `hg_extension_test_base.py` with a `TODO` to
remove `updatecheck` once I can get `update.check` to do its job.

Reviewed By: simpkins

Differential Revision: D6366007

fbshipit-source-id: bb3ecb1270e77d59d7d9e7baa36ada61971bbc49
2017-11-29 21:50:34 -08:00
Wez Furlong
28e74f1ba6 add scmGetStatusBetweenRevisions thrift call
Summary:
The goal is to provide a fast path for watchman to flesh
out the total set of changed files when it needs relay that information
on to consumers.

We choose not to include the full list in the Journal when checking out
between revisions because it will not always be needed and may be an
expensive `O(repo)` operation to compute.  This means that watchman
needs to expand that information for itself, and that is currently
a fairly slow query to invoke through mercurial.

Since watchman is responding to journal events from eden we know that
we have tree data for the old and new hashes and thus we should be
able to efficiently compute that diff.

This implementation is slightly awful because it will instantiate an
unlinked TreeInode object for one side of the query, and will in
turn populate any children that differ as it walks down the tree.
A follow on diff will look at making a flavor of the diff code that
can diff raw Tree objects instead.

Reviewed By: bolinfest

Differential Revision: D6305844

fbshipit-source-id: 7506c9ba1f4febebcdc283c414261810a3951588
2017-11-28 19:36:32 -08:00
Adam Simpkins
fbeb35cbdc fix issues tracking the last checkout time
Summary:
Eden attempts to initialize timestamps of newly loaded inodes with the time of
the last checkout operation performed in this mount.  Unfortunately it had a
number of bugs in this logic:

EdenMount had two separate fields attempting to track the last checkout time:
`lastCheckoutTime_` and `parentInfo_.lastCheckoutTime`.

Unfortunately neither field was actually updated on checkout operations.
Additionally, `lastCheckoutTime_` did not have any locking to allow it to be
updated.  `parentInfo_.lastCheckoutTime` did have locking, but it used the
mount point's checkout lock, so it could not be accessed during checkout
operations.

This diff removes `parentInfo_.lastCheckoutTime`, keeping only
`lastCheckoutTime_`.  It also converts `lastCheckoutTime_` to a
`struct timespec` since this is most often needed as a `timespec`.  It also
adds a new mountpoint-wide lock for synchronizing accessing to this variable.

Reviewed By: bolinfest

Differential Revision: D6356698

fbshipit-source-id: db54f9bb297b5febe4642e2b3fcc8055a6afc199
2017-11-19 15:47:13 -08:00
Michael Bolin
e8d25ee211 Move the post-clone step from C++ to Python.
Summary:
Moving the post-clone step out of C++ makes it so that
`ClientConfig` in C++ no longer knows about `hooks` and requires
`RepoConfig` to know about `hooks`. This helps us reduce
`ClientConfig`'s dependency on `ConfigData`, as my next step
is to move the remaining information that `ClientConfig` gets from
`ConfigData` directly into the client's `edenrc` file under
`~/local/.eden`.

Reviewed By: chadaustin

Differential Revision: D6310544

fbshipit-source-id: dec7a21281ab49e0416b8872757970a4eff2d943
2017-11-14 14:06:25 -08:00
Chad Austin
587d0ad1ee Move Journal locking inside of Journal itself
Summary:
This is follow-up to the lock ordering issues in
StreamingSubscriber.  The Journal locks are now finer-grained and no
locks are held while the subscribers are invoked.  This change
prevents future deadlocks.

Reviewed By: wez

Differential Revision: D6281410

fbshipit-source-id: 797c164395831752f61cc15928b6d4ce4dab1b68
2017-11-10 19:57:49 -08:00
Michael Bolin
5d738193e5 Store Hg dirstate data in Hg instead of Eden.
Summary:
This is a major change to how we manage the dirstate in Eden's Hg extension.

Previously, the dirstate information was stored under `$EDEN_CONFIG_DIR`,
which is Eden's private storage. Any time the Mercurial extension wanted to
read or write the dirstate, it had to make a Thrift request to Eden to do so on
its behalf. The upside is that Eden could answer dirstate-related questions
independently of the Python code.

This was sufficiently different than how Mercurial's default dirstate worked
that our subclass, `eden_dirstate`, had to override quite a bit of behavior.
Failing to manage the `.hg/dirstate` file in a way similar to the way Mercurial
does has exposed some "unofficial contracts" that Mercurial has. For example,
tools like Nuclide rely on changes to the `.hg/dirstate` file as a heuristic to
determine when to invalidate its internal caches for Mercurial data.

Today, Mercurial has a well-factored `dirstatemap` abstraction that is primarily
responsible for the transactions with the dirstate's data. With this split, we can
focus on putting most of our customizations in our `eden_dirstate_map` subclass
while our `eden_dirstate` class has to override fewer methods. Because the
data is managed through the `.hg/dirstate` file, transaction logic in Mercurial that
relies on renaming/copying that file will work out-of-the-box. This change
also reduces the number of Thrift calls the Mercurial extension has to make
for operations like `hg status` or `hg add`.

In this revision, we introduce our own binary format for the `.hg/dirstate` file.
The logic to read and write this file is in `eden/py/dirstate.py`. After the first
40 bytes, which are used for the parent hashes, the next four bytes are
reserved for a version number for the file format so we can manage file format
changes going forward.

Admittedly one downside of this change is that it is a breaking change.
Ideally, users should commit all of their local changes in their existing mounts,
shutdown Eden, delete the old mounts, restart Eden, and re-clone.

In the end, this change deletes a number of Mercurial-specific code and Thrift
APIs from Eden. This is a better separation of concerns that makes Eden more
SCM-agnostic. For example, this change removes `Dirstate.cpp` and
`DirstatePersistance.cpp`, replacing them with the much simpler and more
general `Differ.cpp`. The Mercurial-specific logic from `Dirstate.cpp` that turned
a diff into an `hg status` now lives in the Mercurial extension in
`EdenThriftClient.getStatus()`, which is much more appropriate.

Note that this reverts the changes that were recently introduced in D6116105:
we now need to intercept `localrepo.localrepository.dirstate` once again.

Reviewed By: simpkins

Differential Revision: D6179950

fbshipit-source-id: 5b78904909b669c9cc606e2fe1fd118ef6eaab95
2017-11-06 19:56:49 -08:00
Chad Austin
8b9261f2a1 run clang-format across all C++ files
Summary:
Per discussion with bolinfest, this brings Eden in line with clang-format.

This diff was generated with `find . \( -iname '*.cpp' -o -iname '*.h' \) -exec bash -c "yes | arc lint {}" \;`

Reviewed By: bolinfest

Differential Revision: D6232695

fbshipit-source-id: d54942bf1c69b5b0dcd4df629f1f2d5538c9e28c
2017-11-03 16:02:03 -07:00
Wez Furlong
364398cf94 ObjectStore now returns shared_ptr<const>
Summary:
Originally I thought this would help move towards removing a
`future.get()` call from FileInode, but it turned out to not make a difference
to that code.

It does make it a bit less of a chore to deal with the Journal related diff
callbacks added in D5896494 though, and is a move towards a future where we
could potentially return cached and shared instances of these objects.

This diff is a mechanical change to alter the return type so that we can share
instances returned from the object store interface.  It doesn't change any
functionality.

Reviewed By: simpkins

Differential Revision: D5919268

fbshipit-source-id: efe4b3af74e80cf1df20e81b4386450b72fa2c94
2017-09-29 16:54:05 -07:00
Chad Austin
24c0fe9e8f prefetch inode contents when they're looked up
Reviewed By: wez

Differential Revision: D5817915

fbshipit-source-id: 3820f635cc6251ae5e13a4e214ba66df25ab6687
2017-09-19 11:10:11 -07:00