To make cache stop as simple as possibe and to reduce number of errors, stop
context should be allocated during cache initialize.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
To prevent removing cas_cache module when not all thread were stopped yet, each
of them should keep reference.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
To enable stopping management queue from completion context, last queue_put()
have to be called from separate thread.
After cache is fully deinitialized, thread calls module_put_and_exit() to
prevent scenario when code is still executed, but there are no references to
module.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
If _cas_create_thread() thread failed, queue should be stopped by ocf. One of steps
done during queue stop is stopping kernel thread.
To avoid stopping thread which is not running, additional check was added in
_cas_stop_thread().
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
Right now the classifier is instantiated before device is attached.
This way if we have any IO-classes present on cache device the
classifier will have no knowledge of them and fail to classify IO
correctly.
After moving the classifier init to cache finalization routine we have
all the information needed to initialize properly both in new instance
start path and in load path.
Signed-off-by: Jan Musial <jan.musial@intel.com>
When flushing core, acquiring write lock is not necessary, so it was replaced
with read lock wherever possible.
If flushing operation is interrupted by signal, not only waiting for it to be
finished is interrupted but also OCF flush operation is stopped.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
When flushing cache, acquiring write lock is not necessary, so it was replaced
with read lock wherever possible.
If flushing operation is interrupted by signal, not only waiting for it to be
finished is interrupted but also OCF flush operation is stopped.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
In current OCF cache stop implemetation no error should occur, so there is no
need to handle it in adapter.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
When device used as cache had a big size, it took a lot of time to initialize.
If user would interrupt waiting, asyc OCF init procedure would continue, but
after finish, there was nobody to perfrom kernel part of start nor error
handling.
Now error handling and kernel part of start procedure are moved to completion.
If user will interrupt waiting at any point, newly started cache instance will
be stopped.
Since cache init and load vary only with check for old metadata and initializing
exported objects, they are now merged into one function.
Async cache stop is part of this commit because it was needed for rollback path.
Load, init and stop have common context, because in case of non interrupted
attach CAS needs to wait for rollback to be completed. Common context makes
passing `struct completion` easier between load, init and stop.
This commit is part of patch that will allow to interrupt waiting for OCF
operations.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
When context was allocated on the stack and waiting for completion was
interrupted, completion function would attempt to save flush result in
memory which might in use by other process. This would cause a system crash.
To prevent such scenario, context is allocated dynamiclly and extended with
reference counter. In case of interrupt, completion function doesn't have to
save result in context, it can simply free it's memory.
This commit also enables possibility to interrupt regular flush properly, by
seding SIGING to casadm.
This commit is part of patch that will allow to interrupt waiting for OCF
operations.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
When context was allocated on the stack and waiting for completion was
interrupted, completion function would attempt to save flush result in
memory which might in use by other process. This would cause a system crash.
To prevent such scenario, context is allocated dynamiclly and extended with
reference counter. In case of interrupt, completion function doesn't have to
save result in context, it can simply free it's memory.
This commit is part of patch that will allow to interrupt waiting for OCF
operations.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
When context was allocated on the stack and waiting for completion was
interrupted, completion function would attempt to save lock/unlock result in
memory which might in use by other process. This would cause a system crash.
To prevent such scenario, context is allocated dynamiclly and extended with
reference counter. In case of interrupt, completion function doesn't have to
save result in context, it can simply free it's memory.
This commit is part of patch that will allow to interrupt waiting for OCF
operations.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
They are usually not time comsuming operations, so risk of hung task is low.
So it's easier to temporarily disable interrupts instead of properly handle
async completion.
This commit is part of patch that will handle interrupt of waiting for OCF
operations.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
Usually metadata probe is non time consuming. To avoid dealing with
synchronization problems, noninterruptible wait is performed.
This commit is part of patch that will handle interrupt of waiting for OCF
operations.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
After marking thread as ready to stop, CAS was waiting this for thread to exit
out of main execution loop (in _cas_io_queue_thread()). In case of management
queue it lead to deadlock because both stoping queue and main execution loop was
performed in the same execution context.
Since freeing memory is the only operation after stopping thread, it can be
moved just after the main thread loop. After this little reordering,
synchronising between _cas_stop_thread() and _cas_io_queue_thread() in no longer
needed, and no deadlock will occur.
This change is needed to put management qeueue from completion context. Without
this cachnge, there will be no possiblitiy to stop cache from completion context
and to make rollback.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
Returning non-const char* doesn't have any benefits since
the only caller casts the output pointer to const char *.
This change fixes compilation on 5.3 kernel.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
CAS does not need atomic alocations virtually anywhere. GFP_NOIO
should be sufficient in IO path. When allocation buffers during
module initialization use GFP_KERNEL.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
1. cas_vfree implementation is now properly selected based on kernel version
2. cas_vfree semantics now accepts NULL pionter as a valid input
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
