This incorrect behavior was leading to a call at too high IRQL for paged code.
This was triggered by MS FastFAT.
ReleaseFromLazyWrite call was already correctly called to that regard.
CORE-11819
This avoids performing a double-free (even though that's hidden by the
fact we use lookaside allocations for VACB), and it avoids freeing
a memory address at an uninitialized address.
We don't care about references here, the VACB was just allocated, never
linked and we're its only user.
CORE-15413
Given current ReactOS implementation, a VACB can be pinned
several times, with different BCB. In next commits, a single
BCB will be able to be pinned several times. That would
lead to severe inconsistencies in counting and thus corruption.
kmtest:NtCreateSection calls CcInitializeCacheMap with a
NULL value for SectionObjectPointers. This will cause an exception when
trying to access it, which in Windows can be handled gracefully.
However accessing it while holding ViewLock means the lock will not be
released, leading to an APC_INDEX_MISMATCH bugcheck.
This solves the problem by allocating SharedCacheMap outside the lock,
then freeing it again under lock if another thread has updated SharedCacheMap
in the mean time. This is also What Windows Does(TM).
This avoids a really nasty race condition in our cache controler where
two concurrents could try to initialize cache on the same file.
This had two nasty effects: first shared map was purely leaked and erased
by the second one. And the private cache map, allocated on the first shared
cache map couldn't be freed and was leading to Mm BSOD (free in a middle of
a block).
This was often triggered while building ReactOS on ReactOS (with multi threads).
With that patch, I cannot crash anylonger while building ReactOS.
CORE-14634
Recent changes seem to show that it's not
required to be exclusive on VACB to be able
to flush it.
This commit goes with f2c44aa and fixes the
last issues going with copying huge files.
There are no longer BSODs (be it in Mm or Cc).
I could, with 750MB RAM extract a 2GB file from
a 53MB archive and copy a 2,5GB file from a VBox
share to the disk. Note that writes are often
deferred, so if copy works, it's not that fast for now.
Note that it also brings some beloved behavior from
Windows: copy times are totally unreliable now when
writes are deferred. Little remaining times when
actively copying, high remaining times when deferred
writes in action. And goes between both... Sorry! ;-)
https://xkcd.com/612/
CORE-9696
CORE-11175
Same mechanism exists in Windows (even their Cc
is way different from ours...) where when Cc is
out of memory (in their case, out of VACB), we
will start scavenge old & unused VACB to free
some of the memory.
It's useful in case we're operating we big files
operations, we may run out of memory where to map
VACB for them, so start to scavenge VACB to free
some of that memory.
With this, I am able to install Qt 4.8.6 with 2,5GB of RAM,
scavenging acting when needed!
CORE-12081
CORE-14582
Adjusting refcount and enabling lazy-write for pinned
VACB makes it actually more efficient, often purging
data to disk, reducing memory stress for the system.
This is required for defering writes.
This commit unfortunately (?) reverts a previous revert.
CORE-12081
CORE-14582
CORE-14313
When no name is set in the file object, try to read the name
from the FCB. We only support FastFAT (ours) FCB for now.
This is clearly a hack, but for a kdbg command, so ;-)
It seems that on process killing, some VACB may be deleted while
still mapped. With current reference counting, they will actually
not be deleted, but leaked, and an ASSERT will be triggered.
CORE-14578
This has have several benefits for ReactOS Cc:
- It helps reducing potential deadlocks situations in Cc
- It speeds up ReactOS by reducing locks
- It gets us a bit closer to Windows VACB
CORE-14349
The avoids race conditions where attempts to read from disk to
not fully initialized VACB were performed.
Also, added more debug prints in such situations.
CORE-14349
This allows being consistent between newly created and looked up
so that VACB can always safely be released.
Should really help with reference issues.
CORE-14481
CORE-14480
CORE-14482
This fixes various bugs linked to VACB counting:
- VACB not released when it should be
- Reference count expectations not being accurate
For the record, VACB should always have at least a reference
count of 1, unless you are to free it and removed it from
any linked list.
This commit also adds a bunch of asserts that should
help triggering invalid reference counting.
It should also fix numerous ASSERT currently triggered and
may help fixing random behaviours in Cc.
CORE-14285
CORE-14401
CORE-14293
Standard shared cache map provides space for a private cache map, do the same
and make it available for the first handle. It avoids two allocations in a row.
This halfplements CcScheduleReadAhead() which is responsible for finding the next reads
to perform given last read and previous reads. I made it very basic for now, at least
to test the whole process.
This also introduces the CcExpressWorkQueue in the lazy writer which is responsible
for dealing with read ahead items and which is dealt with before the regular queue.
In CcCopyData(), if read was fine, schedule read ahead so that it can happen in background
without the FSD to notice it! Also, update the read history so that scheduling as a
bit of data.
Implement (à la "old Cc" ;-)) CcPerformReadAhead() which is responsible for performing
the read. It's only to be called by the worker thread.
Side note on the modifications done in CcRosReleaseFileCache(). Private cache map
is tied to a handle. If it goes away, private cache map gets deleted. Read ahead
can run after the handle was closed (and thus, private cache map deleted), so
it is mandatory to always lock the master lock before accessing the structure in
read ahead or before deleting it in CcRosReleaseFileCache(). Otherwise, you'll
just break everything. You've been warned!
This commit also partly reverts f8b5d27.
CORE-14312
before the call to CcRosReleaseFileCache() which expects to have it to properly clean the file.
So, move deletion code to CcRosReleaseFileCache() so that he's the only one to handle private map.
Should hopefully fix all the recent buildbots issues (and the universe perhaps, who knows?)
This reverts BCB being lazy written when marked dirty.
We'll go back to this behavior when this part will have been reworked and stabilized.
CORE-14263
CORE-14279
CORE-14285
Instead move to a threading model like the Windows one.
We'll queue several work items to be executed in a system thread (Cc worker)
when there are VACB that have been marked as dirty. Furthermore, some delay
will be observed before action to avoid killing the system with IOs.
This new threading model opens way for read ahead and write behind implementation.
Also, moved the initialization of the lazy writer to CcInitializeCacheManager()
it has nothing to do with views and shouldn't be initialized there.
Also, moved the lazy writer implementation to its own file.
Modified CcDeferWrite() and CcRosMarkDirtyVacb() to take into account the new threading model.
Introduced new functions:
- CcPostWorkQueue(): post an item to be handled by Cc worker and spawn a worker if required
- CcScanDpc(): called after some time (not to have lazy writer always running) to queue a lazy scan
- CcLazyWriteScan(): the lazy writer we used to have
- CcScheduleLazyWriteScan(): function to call when you want to start a lazy writer run. It will make a DPC after some time and queue execution
- CcWorkerThread(): the worker thread that will handle lazy write, read ahead, and so on
