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path: root/fs/ocfs2/stackglue.c
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2009-06-22ocfs2: Provide the ocfs2_dlm_lvb_valid() stack API.Joel Becker
The Lock Value Block (LVB) of a DLM lock can be lost when nodes die and the DLM cannot reconstruct its state. Clients of the DLM need to know this. ocfs2's internal DLM, o2dlm, explicitly zeroes out the LVB when it loses track of the state. This is not a standard behavior, but ocfs2 has always relied on it. Thus, an o2dlm LVB is always "valid". ocfs2 now supports both o2dlm and fs/dlm via the stack glue. When fs/dlm loses track of an LVBs state, it sets a flag (DLM_SBF_VALNOTVALID) on the Lock Status Block (LKSB). The contents of the LVB may be garbage or merely stale. ocfs2 doesn't want to try to guess at the validity of the stale LVB. Instead, it should be checking the VALNOTVALID flag. As this is the 'standard' way of treating LVBs, we will promote this behavior. We add a stack glue API ocfs2_dlm_lvb_valid(). It returns non-zero when the LVB is valid. o2dlm will always return valid, while fs/dlm will check VALNOTVALID. Signed-off-by: Joel Becker <joel.becker@oracle.com> Acked-by: Mark Fasheh <mfasheh@suse.com>
2008-10-13ocfs2: Remove pointless !!Mark Fasheh
ocfs2_stack_supports_plocks() doesn't need this to properly return a zero or one value. Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-10-13ocfs2: POSIX file locks supportMark Fasheh
This is actually pretty easy since fs/dlm already handles the bulk of the work. The Ocfs2 userspace cluster stack module already uses fs/dlm as the underlying lock manager, so I only had to add the right calls. Cluster-aware POSIX locks ("plocks") can be turned off by the same means at UNIX locks - mount with 'noflocks', or create a local-only Ocfs2 volume. Internally, the file system uses two sets of file_operations, depending on whether cluster aware plocks is required. This turns out to be easier than implementing local-only versions of ->lock. Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-08-25ocfs2: Increment the reference count of an already-active stack.Joel Becker
The ocfs2_stack_driver_request() function failed to increment the refcount of an already-active stack. It only did the increment on the first reference. Whoops. Signed-off-by: Joel Becker <joel.becker@oracle.com> Tested-by: Marcos Matsunaga <marcos.matsunaga@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-06-16ocfs2: Remove ->hangup() from stack glue operations.Joel Becker
The ->hangup() call was only used to execute ocfs2_hb_ctl. Now that the generic stack glue code handles this, the underlying stack drivers don't need to know about it. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-06-16ocfs2: Move the call of ocfs2_hb_ctl into the stack glue.Joel Becker
Take o2hb_stop() out of the o2cb code and make it part of the generic stack glue as ocfs2_leave_group(). This also allows us to remove the ocfs2_get_hb_ctl_path() function - everything to do with hb_ctl is now part of stackglue.c. o2cb no longer needs a ->hangup() function. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-06-16ocfs2: Move the hb_ctl_path sysctl into the stack glue.Joel Becker
ocfs2 needs to call out to the hb_ctl program at unmount for all cluster stacks. The first step is to move the hb_ctl_path sysctl out of the o2cb code and into the generic stack glue. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: add fsdlm to stackglueDavid Teigland
Add code to use fs/dlm. [ Modified to be part of the stack_user module -- Joel ] Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Add the 'cluster_stack' sysfs file.Joel Becker
Userspace can now query and specify the cluster stack in use via the /sys/fs/ocfs2/cluster_stack file. By default, it is 'o2cb', which is the classic stack. Thus, old tools that do not know how to modify this file will work just fine. The stack cannot be modified if there is a live filesystem. ocfs2_cluster_connect() now takes the expected cluster stack as an argument. This way, the filesystem and the stack glue ensure they are speaking to the same backend. If the stack is 'o2cb', the o2cb stack plugin is used. For any other value, the fsdlm stack plugin is selected. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Create stack glue sysfs files.Joel Becker
Introduce a set of sysfs files that describe the current stack glue state. The files live under /sys/fs/ocfs2. The locking_protocol file displays the version of ocfs2's locking code. The loaded_cluster_plugins file displays all of the currently loaded stack plugins. When filesystems are mounted, the active_cluster_plugin file will display the plugin in use. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Break out stackglue into modules.Joel Becker
We define the ocfs2_stack_plugin structure to represent a stack driver. The o2cb stack code is split into stack_o2cb.c. This becomes the ocfs2_stack_o2cb.ko module. The stackglue generic functions are similarly split into the ocfs2_stackglue.ko module. This module now provides an interface to register drivers. The ocfs2_stack_o2cb driver registers itself. As part of this interface, ocfs2_stackglue can load drivers on demand. This is accomplished in ocfs2_cluster_connect(). ocfs2_cluster_disconnect() is now notified when a _hangup() is pending. If a hangup is pending, it will not release the driver module and will let _hangup() do that. Signed-off-by: Joel Becker <joel.becker@oracle.com>
2008-04-18ocfs2: Create ocfs2_stack_operations and split out the o2cb stack.Joel Becker
Define the ocfs2_stack_operations structure. Build o2cb_stack_ops from all of the o2cb-specific stack functions. Change the generic stack glue functions to call the stack_ops instead of the o2cb functions directly. The o2cb functions are moved to stack_o2cb.c. The headers are cleaned up to where only needed headers are included. In this code, stackglue.c and stack_o2cb.c refer to some shared extern variables. When they become modules, that will change. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Split o2cb code from generic stack functions.Joel Becker
Split off the o2cb-specific funtionality from the generic stack glue calls. This is a precurser to wrapping the o2cb functionality in an operations vector. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Clean up stackglue initializationJoel Becker
The stack glue initialization function needs a better name so that it can be used cleanly when stackglue becomes a module. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Abstract out a debugging function for underlying dlms.Joel Becker
dlmglue.c was still referencing a raw o2dlm lksb in one instance. Let's create a generic ocfs2_dlm_dump_lksb() function. This allows underlying DLMs to print whatever they want about their lock. We then move the o2dlm dump into stackglue.c where it belongs. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Remove CANCELGRANT from the view of dlmglue.Joel Becker
o2dlm has the non-standard behavior of providing a cancel callback (unlock_ast) even when the cancel has failed (the locking operation succeeded without canceling). This is called CANCELGRANT after the status code sent to the callback. fs/dlm does not provide this callback, so dlmglue must be changed to live without it. o2dlm_unlock_ast_wrapper() in stackglue now ignores CANCELGRANT calls. Because dlmglue no longer sees CANCELGRANT, ocfs2_unlock_ast() no longer needs to check for it. ocfs2_locking_ast() must catch that a cancel was tried and clear the cancel state. Making these changes opens up a locking race. dlmglue uses the the OCFS2_LOCK_BUSY flag to ensure only one thread is calling the dlm at any one time. But dlmglue must unlock the lockres before calling into the dlm. In the small window of time between unlocking the lockres and calling the dlm, the downconvert thread can try to cancel the lock. The downconvert thread is checking the OCFS2_LOCK_BUSY flag - it doesn't know that ocfs2_dlm_lock() has not yet been called. Because ocfs2_dlm_lock() has not yet been called, the cancel operation will just be a no-op. There's nothing to cancel. With CANCELGRANT, dlmglue uses the CANCELGRANT callback to clear up the cancel state. When it comes around again, it will retry the cancel. Eventually, the first thread will have called into ocfs2_dlm_lock(), and either the lock or the cancel will succeed. The downconvert thread can then do its downconvert. Without CANCELGRANT, there is nothing to clean up the cancellation state. The downconvert thread does not know to retry its operations. More importantly, the original lock may be blocking on the other node that is trying to cancel us. With neither able to make progress, the ast is never called and the cancellation state is never cleaned up that way. dlmglue is deadlocked. The OCFS2_LOCK_PENDING flag is introduced to remedy this window. It is set at the same time OCFS2_LOCK_BUSY is. Thus, the downconvert thread can check whether the lock is cancelable. If not, it just loops around to try again. Once ocfs2_dlm_lock() is called, the thread then clears OCFS2_LOCK_PENDING and wakes the downconvert thread. Now, if the downconvert thread finds the lock BUSY, it can safely try to cancel it. Whether the cancel works or not, the state will be properly set and the lock processing can continue. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Move o2hb functionality into the stack glue.Joel Becker
The last bit of classic stack used directly in ocfs2 code is o2hb. Specifically, the check for heartbeat during mount and the call to ocfs2_hb_ctl during unmount. We create an extra API, ocfs2_cluster_hangup(), to encapsulate the call to ocfs2_hb_ctl. Other stacks will just leave hangup() empty. The check for heartbeat is moved into ocfs2_cluster_connect(). It will be matched by a similar check for other stacks. With this change, only stackglue.c includes cluster/ headers. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Abstract out node number queries.Joel Becker
ocfs2 asks the cluster stack for the local node's node number for two reasons; to fill the slot map and to print it. While the slot map isn't necessary for userspace cluster stacks, the printing is very nice for debugging. Thus we add ocfs2_cluster_this_node() as a generic API to get this value. It is anticipated that the slot map will not be used under a userspace cluster stack, so validity checks of the node num only need to exist in the slot map code. Otherwise, it just gets used and printed as an opaque value. [ Fixed up some "int" versus "unsigned int" issues and made osb->node_num truly opaque. --Mark ] Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Introduce the new ocfs2_cluster_connect/disconnect() API.Joel Becker
This step introduces a cluster stack agnostic API for initializing and exiting. fs/ocfs2/dlmglue.c no longer uses o2cb/o2dlm knowledge to connect to the stack. It is all handled in stackglue.c. heartbeat.c no longer needs to know how it gets called. ocfs2_do_node_down() is now a clean recovery trigger. The big gotcha is the ordering of initializations and de-initializations done underneath ocfs2_cluster_connect(). ocfs2_dlm_init() used to do all o2dlm initialization in one block. Thus, the o2dlm functionality of ocfs2_cluster_connect() is very straightforward. ocfs2_dlm_shutdown(), however, did a few things between de-registration of the eviction callback and actually shutting down the domain. Now de-registration and shutdown of the domain are wrapped within the single ocfs2_cluster_disconnect() call. I've checked the code paths to make sure we can safely tear down things in ocfs2_dlm_shutdown() before calling ocfs2_cluster_disconnect(). The filesystem has already set itself to ignore the callback. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Create the lock status block union.Joel Becker
Wrap the lock status block (lksb) in a union. Later we will add a union element for the fs/dlm lksb. Create accessors for the status and lvb fields. Other than a debugging function, dlmglue.c does not directly reference the o2dlm locking path anymore. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Use -errno instead of dlm_status for ocfs2_dlm_lock/unlock() API.Joel Becker
Change the ocfs2_dlm_lock/unlock() functions to return -errno values. This is the first step towards elminiating dlm_status in fs/ocfs2/dlmglue.c. The change also passes -errno values to ->unlock_ast(). [ Fix a return code in dlmglue.c and change the error translation table into an array of ints. --Mark ] Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Use global DLM_ constants in generic code.Joel Becker
The ocfs2 generic code should use the values in <linux/dlmconstants.h>. stackglue.c will convert them to o2dlm values. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Separate out dlm lock functions.Joel Becker
This is the first in a series of patches to isolate ocfs2 from the underlying cluster stack. Here we wrap the dlm locking functions with ocfs2-specific calls. Because ocfs2 always uses the same dlm lock status callbacks, we can eliminate the callbacks from the filesystem visible functions. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>