s3 OneFS: Add kernel oplocks implementation

A few functions in oplocks_onefs.c need to be accessed from the onefs
vfs module.  It would be ideal if oplocks were implemented at the vfs
layer, but since they aren't yet, a new header is added to
source3/include to make these functions available to the onefs vfs
module.  oplocks_onefs.o doesn't need to be linked into the onefs vfs
module explicitly, since it is already linked into smbd by default.

2 files changed, 805 insertions, 0 deletions

diff --git a/source3/smbd/oplock.c b/source3/smbd/oplock.c
index a6ec9cfa2d..b39e5bf634 100644
--- a/source3/smbd/oplock.c
+++ b/source3/smbd/oplock.c
@@ -122,6 +122,11 @@ void release_file_oplock(files_struct *fsp)
 
 static void downgrade_file_oplock(files_struct *fsp)
 {
+	if (!EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type)) {
+		DEBUG(0, ("trying to downgrade an already-downgraded oplock!\n"));
+		return;
+	}
+
 	if (koplocks) {
 		koplocks->ops->release_oplock(koplocks, fsp, LEVEL_II_OPLOCK);
 	}
@@ -916,6 +921,8 @@ bool init_oplocks(struct messaging_context *msg_ctx)
 		koplocks = irix_init_kernel_oplocks(talloc_autofree_context());
 #elif HAVE_KERNEL_OPLOCKS_LINUX
 		koplocks = linux_init_kernel_oplocks(talloc_autofree_context());
+#elif HAVE_ONEFS
+		koplocks = onefs_init_kernel_oplocks(talloc_autofree_context());
 #endif
 	}
 
diff --git a/source3/smbd/oplock_onefs.c b/source3/smbd/oplock_onefs.c
new file mode 100644
index 0000000000..0908ce4386
--- /dev/null
+++ b/source3/smbd/oplock_onefs.c
@@ -0,0 +1,798 @@
+/*
+ * Unix SMB/CIFS implementation.
+ * Support for OneFS kernel oplocks
+ *
+ * Copyright (C) Volker Lendecke 2007
+ * Copyright (C) Tim Prouty, 2009
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define DBGC_CLASS DBGC_LOCKING
+
+#include "includes.h"
+
+#if HAVE_ONEFS
+#include "oplock_onefs.h"
+#include "smbd/globals.h"
+
+#include <ifs/ifs_syscalls.h>
+#include <isi_ecs/isi_ecs_oplocks.h>
+#include <sys/proc.h>
+
+struct onefs_oplocks_context {
+	struct kernel_oplocks *ctx;
+	const struct oplocks_event_ops *onefs_ops;
+	int onefs_event_fd;
+	struct fd_event *read_fde;
+};
+
+enum onefs_callback_state {
+	ONEFS_OPEN_FILE,
+	ONEFS_WAITING_FOR_OPLOCK
+};
+
+struct onefs_callback_record {
+	struct onefs_callback_record *prev, *next;
+	uint64_t id;
+	enum onefs_callback_state state;
+	union {
+		files_struct *fsp;	/* ONEFS_OPEN_FILE */
+		uint16_t mid;		/* ONEFS_WAITING_FOR_OPLOCK */
+	} data;
+};
+
+/**
+ * Internal list of files (along with additional state) that have outstanding
+ * oplocks or requests for oplocks.
+ */
+struct onefs_callback_record *callback_recs;
+
+/**
+ * Convert a onefs_callback_record to a string.
+ */
+static char *onefs_callback_record_str_static(const struct onefs_callback_record *r)
+{
+	static fstring result;
+
+	if (r == NULL) {
+		fstrcpy(result, "NULL callback record");
+		return result;
+	}
+
+	switch (r->state) {
+	case ONEFS_OPEN_FILE:
+		fstr_sprintf(result, "cb record %llu for file %s",
+			     r->id, r->data.fsp->fsp_name);
+		break;
+	case ONEFS_WAITING_FOR_OPLOCK:
+		fstr_sprintf(result, "cb record %llu for pending mid %d",
+			     r->id, (int)r->data.mid);
+		break;
+	default:
+		fstr_sprintf(result, "cb record %llu unknown state %d",
+			     r->id, r->state);
+		break;
+	}
+
+	return result;
+}
+
+/**
+ * Traverse the list of onefs_callback_records and print all entries.
+ */
+static void debug_cb_records(const char *fn)
+{
+	struct onefs_callback_record *rec;
+
+	if (DEBUGLEVEL < 10)
+		return;
+
+	DEBUG(10, ("cb records (%s):\n", fn));
+
+	for (rec = callback_recs; rec; rec = rec->next) {
+		DEBUGADD(10, ("%s\n", onefs_callback_record_str_static(rec)));
+	}
+}
+
+/**
+ * Find a callback record in the list of outstanding oplock operations.
+ *
+ * Once n ifs_createfile requests an oplock on a file, the kernel communicates
+ * with samba via the oplock event channel by sending events that reference an
+ * id.  This function maps that id to the onefs_callback_record that was
+ * created for it during the initial setup on open (onefs_oplock_wait_record).
+ * When a matching id is found in the onefs_callback_record list, the
+ * callback_type is checked to make sure the record is in in the correct
+ * state.
+ */
+static struct onefs_callback_record *onefs_find_cb(uint64_t id,
+    enum onefs_callback_state expected_state)
+{
+	struct onefs_callback_record *rec;
+
+	debug_cb_records("onefs_find_cb");
+
+	for (rec = callback_recs; rec; rec = rec->next) {
+		if (rec->id == id) {
+			DEBUG(10, ("found %s\n",
+				   onefs_callback_record_str_static(rec)));
+			break;
+		}
+	}
+
+	if (rec == NULL) {
+		DEBUG(5, ("Could not find callback record for id %llu\n", id));
+		return NULL;
+	}
+
+	if (rec->state != expected_state) {
+		DEBUG(0, ("Expected cb type %d, got %s", expected_state,
+			  onefs_callback_record_str_static(rec)));
+		SMB_ASSERT(0);
+		return NULL;
+	}
+
+	return rec;
+}
+
+/**
+ * Remove and free a callback record from the callback record list.
+ */
+void destroy_onefs_callback_record(uint64_t id)
+{
+	struct onefs_callback_record *rec;
+
+	debug_cb_records("destroy_onefs_callback_record");
+
+	if (id == 0) {
+		DEBUG(10, ("destroy_onefs_callback_record: Nothing to "
+			   "destroy\n"));
+		return;
+	}
+
+	for (rec = callback_recs; rec; rec = rec->next) {
+		if (rec->id == id) {
+			DLIST_REMOVE(callback_recs, rec);
+			SAFE_FREE(rec);
+			DEBUG(10, ("removed cb rec %llu\n", id));
+			return;
+		}
+	}
+
+	DEBUG(0, ("Could not find cb rec %llu to delete", id));
+	SMB_ASSERT(0);
+}
+
+/**
+ * Initialize a callback record and add it to the list of outstanding callback
+ * records.
+ *
+ * This is called in the open path before ifs_createfile so an id can be
+ * passed in.  Each callback record can be in one of two states:
+ *
+ *   1. WAITING_FOR_OPLOCK: This is the initial state for all callback
+ *   records.  If ifs_createfile can be completed syncronously without needing
+ *   to break any level I oplocks, the state is transitioned to OPEN_FILE.
+ *   Otherwise ifs_createfile will finish asynchronously and the open is
+ *   deferred.  When the necessary level I opocks have been broken, and the
+ *   open can be done, an event is sent by the kernel on the oplock event
+ *   channel, which is handled by semlock_available_handler.  At this point
+ *   the deferred open is retried.  Unless a level I oplock was acquired by
+ *   another client, ifs_createfile will now complete synchronously.
+ *
+ *   2. OPEN_FILE: Once ifs_createfile completes, the callback record is
+ *   transitioned to this state via onefs_set_oplock_callback.
+ */
+uint64_t onefs_oplock_wait_record(uint16_t mid)
+{
+	struct onefs_callback_record *result;
+	static uint64_t id_generator = 0;
+
+	if (!(result = SMB_MALLOC_P(struct onefs_callback_record))) {
+		DEBUG(0, ("talloc failed\n"));
+		return 0;
+	}
+
+	memset(result, '\0', sizeof(result));
+
+	id_generator += 1;
+	if (id_generator == 0) {
+		/* Wow, that's a long-running smbd... */
+		id_generator += 1;
+	}
+
+	result->id = id_generator;
+
+	result->state = ONEFS_WAITING_FOR_OPLOCK;
+	result->data.mid = mid;
+	DLIST_ADD(callback_recs, result);
+
+	DEBUG(10, ("New cb rec %llu created\n", result->id));
+
+	return result->id;
+}
+
+/**
+ * Transition the callback record state to OPEN_FILE.
+ *
+ * This is called after the file is opened and an fsp struct has been
+ * allocated.  The mid is dropped in favor of storing the fsp.
+ */
+void onefs_set_oplock_callback(uint64_t id, files_struct *fsp)
+{
+	struct onefs_callback_record *cb;
+	char *msg;
+
+	DEBUG(10, ("onefs_set_oplock_callback called for cb rec %llu\n", id));
+
+	if (!(cb = onefs_find_cb(id, ONEFS_WAITING_FOR_OPLOCK))) {
+		if (asprintf(&msg, "Got invalid callback %lld\n", id) != -1) {
+			smb_panic(msg);
+		}
+		smb_panic("Got invalid callback id\n");
+	}
+
+	/*
+	 * Paranoia check
+	 */
+	if (open_was_deferred(cb->data.mid)) {
+		if (asprintf(&msg, "Trying to upgrade callback for deferred "
+			     "open mid=%d\n", cb->data.mid) != -1) {
+			smb_panic(msg);
+		}
+		smb_panic("Trying to upgrade callback for deferred open "
+			  "mid\n");
+	}
+
+	cb->state = ONEFS_OPEN_FILE;
+	cb->data.fsp = fsp;
+}
+
+/**
+ * Using a callback record, initialize a share mode entry to pass to
+ * share_mode_entry_to_message to send samba IPC messages.
+ */
+static void init_share_mode_entry(struct share_mode_entry *sme,
+				  struct onefs_callback_record *cb,
+				  int op_type)
+{
+	ZERO_STRUCT(*sme);
+
+	sme->pid = procid_self();
+	sme->op_type = op_type;
+	sme->id = cb->data.fsp->file_id;
+	sme->share_file_id = cb->data.fsp->fh->gen_id;
+}
+
+/**
+ * Callback when a break-to-none event is received from the kernel.
+ *
+ * On OneFS level 1 oplocks are always broken to level 2 first, therefore an
+ * async level 2 break message is always sent when breaking to none.  The
+ * downside of this is that OneFS currently has no way to express breaking
+ * directly from level 1 to none.
+ */
+static void oplock_break_to_none_handler(uint64_t id)
+{
+	struct onefs_callback_record *cb;
+	struct share_mode_entry sme;
+	char msg[MSG_SMB_SHARE_MODE_ENTRY_SIZE];
+
+	DEBUG(10, ("oplock_break_to_none_handler called for id %llu\n", id));
+
+	if (!(cb = onefs_find_cb(id, ONEFS_OPEN_FILE))) {
+		DEBUG(3, ("oplock_break_to_none_handler: could not find "
+			  "callback id %llu\n", id));
+		return;
+	}
+
+	DEBUG(10, ("oplock_break_to_none_handler called for file %s\n",
+		   cb->data.fsp->fsp_name));
+
+	init_share_mode_entry(&sme, cb, FORCE_OPLOCK_BREAK_TO_NONE);
+	share_mode_entry_to_message(msg, &sme);
+	messaging_send_buf(smbd_messaging_context(),
+			   sme.pid,
+			   MSG_SMB_ASYNC_LEVEL2_BREAK,
+			   (uint8_t *)msg,
+			   MSG_SMB_SHARE_MODE_ENTRY_SIZE);
+
+	/*
+	 * We could still receive an OPLOCK_REVOKED message, so keep the
+	 * oplock_callback_id around.
+	 */
+}
+
+/**
+ * Callback when a break-to-level2 event is received from the kernel.
+ *
+ * Breaks from level 1 to level 2.
+ */
+static void oplock_break_to_level_two_handler(uint64_t id)
+{
+	struct onefs_callback_record *cb;
+	struct share_mode_entry sme;
+	char msg[MSG_SMB_SHARE_MODE_ENTRY_SIZE];
+
+	DEBUG(10, ("oplock_break_to_level_two_handler called for id %llu\n",
+		   id));
+
+	if (!(cb = onefs_find_cb(id, ONEFS_OPEN_FILE))) {
+		DEBUG(3, ("oplock_break_to_level_two_handler: could not find "
+			  "callback id %llu\n", id));
+		return;
+	}
+
+	DEBUG(10, ("oplock_break_to_level_two_handler called for file %s\n",
+		   cb->data.fsp->fsp_name));
+
+	init_share_mode_entry(&sme, cb, LEVEL_II_OPLOCK);
+	share_mode_entry_to_message(msg, &sme);
+	messaging_send_buf(smbd_messaging_context(),
+			  sme.pid,
+			  MSG_SMB_BREAK_REQUEST,
+			  (uint8_t *)msg,
+			  MSG_SMB_SHARE_MODE_ENTRY_SIZE);
+
+	/*
+	 * We could still receive an OPLOCK_REVOKED or OPLOCK_BREAK_TO_NONE
+	 * message, so keep the oplock_callback_id around.
+	 */
+}
+
+/**
+ * Revoke an oplock from an unresponsive client.
+ *
+ * The kernel will send this message when it times out waiting for a level 1
+ * oplock break to be acknowledged by the client.  The oplock is then
+ * immediately removed.
+ */
+static void oplock_revoked_handler(uint64_t id)
+{
+	struct onefs_callback_record *cb;
+	files_struct *fsp = NULL;
+
+	DEBUG(10, ("oplock_revoked_handler called for id %llu\n", id));
+
+	if (!(cb = onefs_find_cb(id, ONEFS_OPEN_FILE))) {
+		DEBUG(3, ("oplock_revoked_handler: could not find "
+			  "callback id %llu\n", id));
+		return;
+	}
+
+	fsp = cb->data.fsp;
+
+	SMB_ASSERT(fsp->oplock_timeout == NULL);
+
+	DEBUG(0,("Level 1 oplock break failed for file %s. Forcefully "
+		 "revoking oplock\n", fsp->fsp_name));
+
+	global_client_failed_oplock_break = True;
+	remove_oplock(fsp);
+
+	/*
+	 * cb record is cleaned up in fsp ext data destructor on close, so
+	 * leave it in the list.
+	 */
+}
+
+/**
+ * Asynchronous ifs_createfile callback
+ *
+ * If ifs_createfile had to asynchronously break any oplocks, this function is
+ * called when the kernel sends an event that the open can be retried.
+ */
+static void semlock_available_handler(uint64_t id)
+{
+	struct onefs_callback_record *cb;
+
+	DEBUG(10, ("semlock_available_handler called: %llu\n", id));
+
+	if (!(cb = onefs_find_cb(id, ONEFS_WAITING_FOR_OPLOCK))) {
+		DEBUG(5, ("semlock_available_handler: Did not find callback "
+			  "%llu\n", id));
+		return;
+	}
+
+	DEBUG(10, ("Got semlock available for mid %d\n", cb->data.mid));
+
+	/* Paranoia check */
+	if (!(open_was_deferred(cb->data.mid))) {
+		char *msg;
+		if (asprintf(&msg, "Semlock available on an open that wasn't "
+			     "deferred: %s\n",
+			      onefs_callback_record_str_static(cb)) != -1) {
+			smb_panic(msg);
+		}
+		smb_panic("Semlock available on an open that wasn't "
+			  "deferred\n");
+	}
+
+	schedule_deferred_open_smb_message(cb->data.mid);
+
+	/* Cleanup the callback record since the open will be retried. */
+	destroy_onefs_callback_record(id);
+
+	return;
+}
+
+/**
+ * Asynchronous ifs_createfile failure callback
+ *
+ * If ifs_createfile had to asynchronously break any oplocks, but an error was
+ * encountered in the kernel, the open will be retried with the state->failed
+ * set to true.  This will prompt the open path to send an INTERNAL_ERROR
+ * error message to the client.
+ */
+static void semlock_async_failure_handler(uint64_t id)
+{
+	struct onefs_callback_record *cb;
+	struct pending_message_list *pml;
+	struct deferred_open_record *state;
+
+	DEBUG(1, ("semlock_async_failure_handler called: %llu\n", id));
+
+	if (!(cb = onefs_find_cb(id, ONEFS_WAITING_FOR_OPLOCK))) {
+		DEBUG(5, ("semlock_async_failure_handler: Did not find callback "
+			  "%llu\n", id));
+		return;
+	}
+
+	DEBUG(1, ("Got semlock_async_failure message for mid %d\n", cb->data.mid));
+
+	/* Paranoia check */
+	if (!(open_was_deferred(cb->data.mid))) {
+		char *msg;
+		if (asprintf(&msg, "Semlock failure on an open that wasn't "
+			     "deferred: %s\n",
+			      onefs_callback_record_str_static(cb)) != -1) {
+			smb_panic(msg);
+		}
+		smb_panic("Semlock failure on an open that wasn't deferred\n");
+	}
+
+	/* Find the actual deferred open record. */
+	if (!(pml = get_open_deferred_message(cb->data.mid))) {
+		DEBUG(0, ("Could not find deferred request for "
+			  "mid %d\n", cb->data.mid));
+		destroy_onefs_callback_record(id);
+		return;
+	}
+	state = (struct deferred_open_record *)pml->private_data.data;
+
+	/* Update to failed so the client can be notified on retried open. */
+	state->failed = true;
+
+	/* Schedule deferred open for immediate retry. */
+	schedule_deferred_open_smb_message(cb->data.mid);
+
+	/* Cleanup the callback record here since the open will be retried. */
+	destroy_onefs_callback_record(id);
+
+	return;
+}
+
+/**
+ * OneFS acquires all oplocks via ifs_createfile, so this is a no-op.
+ */
+static bool onefs_set_kernel_oplock(struct kernel_oplocks *_ctx,
+				    files_struct *fsp, int oplock_type) {
+	return true;
+}
+
+/**
+ * Release the kernel oplock.
+ */
+static void onefs_release_kernel_oplock(struct kernel_oplocks *_ctx,
+					files_struct *fsp, int oplock_type)
+{
+	enum oplock_type oplock = onefs_samba_oplock_to_oplock(oplock_type);
+
+	DEBUG(10, ("onefs_release_kernel_oplock: Releasing %s to type %s\n",
+		   fsp->fsp_name, onefs_oplock_str(oplock)));
+
+	if (fsp->fh->fd == -1) {
+		DEBUG(1, ("no fd\n"));
+		return;
+	}
+
+	/* Downgrade oplock to either SHARED or NONE. */
+	if (ifs_oplock_downgrade(fsp->fh->fd, oplock)) {
+		DEBUG(1,("ifs_oplock_downgrade failed: %s\n",
+			 strerror(errno)));
+	}
+}
+
+/**
+ * Wrap ifs_semlock_write so it is only called on operations that aren't
+ * already contended in the kernel.
+ */
+static void onefs_semlock_write(int fd, enum level2_contention_type type,
+				enum semlock_operation semlock_op)
+{
+	int ret;
+
+	switch (type) {
+	case LEVEL2_CONTEND_ALLOC_GROW:
+	case LEVEL2_CONTEND_WINDOWS_BRL:
+	case LEVEL2_CONTEND_POSIX_BRL:
+		DEBUG(10, ("Taking %d write semlock for cmd %d on fd: %d\n",
+			   semlock_op, type, fd));
+		ret = ifs_semlock_write(fd, semlock_op);
+		if (ret) {
+			DEBUG(0,("ifs_semlock_write failed taking %d write "
+				 "semlock for cmd %d on fd: %d: %s",
+				 semlock_op, type, fd, strerror(errno)));
+		}
+		break;
+	default:
+		DEBUG(10, ("Skipping write semlock for cmd %d on fd: %d\n",
+			   type, fd));
+	}
+}
+
+/**
+ * Contend level 2 oplocks in the kernel and smbd.
+ *
+ * Taking a write semlock will contend all level 2 oplocks in all smbds across
+ * the cluster except the fsp's own level 2 oplock.  This lack of
+ * self-contention is a limitation of the current OneFS kernel oplocks
+ * implementation.  Luckily it is easy to contend our own level 2 oplock by
+ * iterating the share mode entries and only breaking the oplock if the pid
+ * matches our's.
+ */
+static void onefs_contend_level2_oplocks_begin(files_struct *fsp,
+					       enum level2_contention_type type)
+{
+	int i;
+	struct share_mode_lock *lck;
+
+	/* Take care of level 2 kernel contention. */
+	onefs_semlock_write(fsp->fh->fd, type, SEMLOCK_LOCK);
+
+	/*
+	 * If this file is level II oplocked then we need
+	 * to grab the shared memory lock and inform all
+	 * other files with a level II lock that they need
+	 * to flush their read caches. We keep the lock over
+	 * the shared memory area whilst doing this.
+	 */
+
+	if (!LEVEL_II_OPLOCK_TYPE(fsp->oplock_type))
+		return;
+
+	lck = get_share_mode_lock(talloc_tos(), fsp->file_id, NULL, NULL,
+				  NULL);
+	if (lck == NULL) {
+		DEBUG(0,("onefs_contend_level2_oplocks_begin: failed to lock "
+			 "share mode entry for file %s.\n", fsp->fsp_name ));
+		return;
+	}
+
+	DEBUG(10,("onefs_contend_level2_oplocks_begin: num_share_modes = %d\n",
+		  lck->num_share_modes ));
+
+	for(i = 0; i < lck->num_share_modes; i++) {
+		struct share_mode_entry *share_entry = &lck->share_modes[i];
+		char msg[MSG_SMB_SHARE_MODE_ENTRY_SIZE];
+
+		if (!is_valid_share_mode_entry(share_entry)) {
+			continue;
+		}
+
+		DEBUG(10,("onefs_contend_level2_oplocks_begin: "
+			  "share_entry[%i]->op_type == %d\n",
+			  i, share_entry->op_type ));
+
+		if (share_entry->op_type == NO_OPLOCK) {
+			continue;
+		}
+
+		/* Paranoia .... */
+		if (EXCLUSIVE_OPLOCK_TYPE(share_entry->op_type)) {
+			DEBUG(0,("onefs_contend_level2_oplocks_begin: PANIC. "
+				 "share mode entry %d is an exlusive "
+				 "oplock !\n", i ));
+			TALLOC_FREE(lck);
+			abort();
+		}
+
+		share_mode_entry_to_message(msg, share_entry);
+
+		/*
+		 * Only contend our own level 2 oplock.  The other processes
+		 * will be get break events from the kernel.
+		 */
+		if (procid_is_me(&share_entry->pid)) {
+			DATA_BLOB blob = data_blob_const(msg,
+			    MSG_SMB_SHARE_MODE_ENTRY_SIZE);
+			process_oplock_async_level2_break_message(
+				smbd_messaging_context(),
+				NULL,
+				MSG_SMB_ASYNC_LEVEL2_BREAK,
+				share_entry->pid,
+				&blob);
+		}
+	}
+
+	/* We let the message receivers handle removing the oplock state
+	   in the share mode lock db. */
+
+	TALLOC_FREE(lck);
+}
+
+/**
+ * Unlock the write semlock when the level 2 contending operation ends.
+ */
+static void onefs_contend_level2_oplocks_end(files_struct *fsp,
+					     enum level2_contention_type type)
+{
+	/* Take care of level 2 kernel contention. */
+	onefs_semlock_write(fsp->fh->fd, type, SEMLOCK_UNLOCK);
+}
+
+/**
+ * Return string value of onefs oplock types.
+ */
+const char *onefs_oplock_str(enum oplock_type onefs_oplock_type)
+{
+	switch (onefs_oplock_type) {
+	case OPLOCK_NONE:
+		return "OPLOCK_NONE";
+	case OPLOCK_EXCLUSIVE:
+		return "OPLOCK_EXCLUSIVE";
+	case OPLOCK_BATCH:
+		return "OPLOCK_BATCH";
+	case OPLOCK_SHARED:
+		return "OPLOCK_SHARED";
+	default:
+		break;
+	}
+	return "UNKNOWN";
+}
+
+/**
+ * Convert from onefs to samba oplock.
+ */
+int onefs_oplock_to_samba_oplock(enum oplock_type onefs_oplock)
+{
+	switch (onefs_oplock) {
+	case OPLOCK_NONE:
+		return NO_OPLOCK;
+	case OPLOCK_EXCLUSIVE:
+		return EXCLUSIVE_OPLOCK;
+	case OPLOCK_BATCH:
+		return BATCH_OPLOCK;
+	case OPLOCK_SHARED:
+		return LEVEL_II_OPLOCK;
+	default:
+		DEBUG(0, ("unknown oplock type %d found\n", onefs_oplock));
+		break;
+	}
+	return NO_OPLOCK;
+}
+
+/**
+ * Convert from samba to onefs oplock.
+ */
+enum oplock_type onefs_samba_oplock_to_oplock(int samba_oplock_type)
+{
+	if (BATCH_OPLOCK_TYPE(samba_oplock_type)) return OPLOCK_BATCH;
+	if (EXCLUSIVE_OPLOCK_TYPE(samba_oplock_type)) return OPLOCK_EXCLUSIVE;
+	if (LEVEL_II_OPLOCK_TYPE(samba_oplock_type)) return OPLOCK_SHARED;
+	return OPLOCK_NONE;
+}
+
+/**
+ * Oplock event handler.
+ *
+ * Call into the event system dispatcher to handle each event.
+ */
+static void onefs_oplocks_read_fde_handler(struct event_context *ev,
+					   struct fd_event *fde,
+					   uint16_t flags,
+					   void *private_data)
+{
+	struct onefs_oplocks_context *ctx =
+	    talloc_get_type(private_data, struct onefs_oplocks_context);
+
+	if (oplocks_event_dispatcher(ctx->onefs_ops)) {
+		DEBUG(0, ("oplocks_event_dispatcher failed: %s\n",
+			  strerror(errno)));
+	}
+}
+
+/**
+ * Setup kernel oplocks
+ */
+static const struct kernel_oplocks_ops onefs_koplocks_ops = {
+	.set_oplock			= onefs_set_kernel_oplock,
+	.release_oplock			= onefs_release_kernel_oplock,
+	.contend_level2_oplocks_begin	= onefs_contend_level2_oplocks_begin,
+	.contend_level2_oplocks_end	= onefs_contend_level2_oplocks_end,
+};
+
+static const struct oplocks_event_ops onefs_dispatch_ops = {
+	.oplock_break_to_none = oplock_break_to_none_handler,
+	.oplock_break_to_level_two = oplock_break_to_level_two_handler,
+	.oplock_revoked = oplock_revoked_handler,
+	.semlock_available = semlock_available_handler,
+	.semlock_async_failure = semlock_async_failure_handler,
+};
+
+struct kernel_oplocks *onefs_init_kernel_oplocks(TALLOC_CTX *mem_ctx)
+{
+	struct kernel_oplocks *_ctx = NULL;
+	struct onefs_oplocks_context *ctx = NULL;
+        struct procoptions po = PROCOPTIONS_INIT;
+
+	DEBUG(10, ("onefs_init_kernel_oplocks called\n"));
+
+	/* Set the non-blocking proc flag */
+	po.po_flags_on |= P_NON_BLOCKING_SEMLOCK;
+	if (setprocoptions(&po) != 0) {
+		DEBUG(0, ("setprocoptions failed: %s.\n", strerror(errno)));
+		goto err_out;
+	}
+
+	/* Setup the oplock contexts */
+	_ctx = talloc_zero(mem_ctx, struct kernel_oplocks);
+	if (!_ctx) {
+		goto err_out;
+	}
+
+	ctx = talloc_zero(_ctx, struct onefs_oplocks_context);
+	if (!ctx) {
+		goto err_out;
+	}
+
+	_ctx->ops = &onefs_koplocks_ops;
+	_ctx->flags = (KOPLOCKS_LEVEL2_SUPPORTED |
+		       KOPLOCKS_DEFERRED_OPEN_NOTIFICATION |
+		       KOPLOCKS_TIMEOUT_NOTIFICATION |
+		       KOPLOCKS_OPLOCK_BROKEN_NOTIFICATION);
+	_ctx->private_data = ctx;
+	ctx->ctx = _ctx;
+	ctx->onefs_ops = &onefs_dispatch_ops;
+
+	/* Register an kernel event channel for oplocks */
+	ctx->onefs_event_fd = oplocks_event_register();
+	if (ctx->onefs_event_fd == -1) {
+		DEBUG(0, ("oplocks_event_register failed: %s\n",
+			   strerror(errno)));
+		goto err_out;
+	}
+
+	DEBUG(10, ("oplock event_fd = %d\n", ctx->onefs_event_fd));
+
+	/* Register the oplock event_fd with samba's event system */
+	ctx->read_fde = event_add_fd(smbd_event_context(),
+				     ctx,
+				     ctx->onefs_event_fd,
+				     EVENT_FD_READ,
+				     onefs_oplocks_read_fde_handler,
+				     ctx);
+	return _ctx;
+
+ err_out:
+	talloc_free(_ctx);
+	talloc_free(ctx);
+	return NULL;
+}
+
+#else
+ void oplock_onefs_dummy(void);
+ void oplock_onefs_dummy(void) {}
+#endif /* HAVE_ONEFS */