1 files changed, 89 insertions, 0 deletions
diff --git a/uts/common/fs/zfs/sys/zfs_rlock.h b/uts/common/fs/zfs/sys/zfs_rlock.h
new file mode 100644
index 000000000000..f302b663e22a
--- /dev/null
+++ b/uts/common/fs/zfs/sys/zfs_rlock.h
@@ -0,0 +1,89 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#ifndef	_SYS_FS_ZFS_RLOCK_H
+#define	_SYS_FS_ZFS_RLOCK_H
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+#ifdef _KERNEL
+
+#include <sys/zfs_znode.h>
+
+typedef enum {
+	RL_READER,
+	RL_WRITER,
+	RL_APPEND
+} rl_type_t;
+
+typedef struct rl {
+	znode_t *r_zp;		/* znode this lock applies to */
+	avl_node_t r_node;	/* avl node link */
+	uint64_t r_off;		/* file range offset */
+	uint64_t r_len;		/* file range length */
+	uint_t r_cnt;		/* range reference count in tree */
+	rl_type_t r_type;	/* range type */
+	kcondvar_t r_wr_cv;	/* cv for waiting writers */
+	kcondvar_t r_rd_cv;	/* cv for waiting readers */
+	uint8_t r_proxy;	/* acting for original range */
+	uint8_t r_write_wanted;	/* writer wants to lock this range */
+	uint8_t r_read_wanted;	/* reader wants to lock this range */
+} rl_t;
+
+/*
+ * Lock a range (offset, length) as either shared (READER)
+ * or exclusive (WRITER or APPEND). APPEND is a special type that
+ * is converted to WRITER that specified to lock from the start of the
+ * end of file.  zfs_range_lock() returns the range lock structure.
+ */
+rl_t *zfs_range_lock(znode_t *zp, uint64_t off, uint64_t len, rl_type_t type);
+
+/*
+ * Unlock range and destroy range lock structure.
+ */
+void zfs_range_unlock(rl_t *rl);
+
+/*
+ * Reduce range locked as RW_WRITER from whole file to specified range.
+ * Asserts the whole file was previously locked.
+ */
+void zfs_range_reduce(rl_t *rl, uint64_t off, uint64_t len);
+
+/*
+ * AVL comparison function used to compare range locks
+ */
+int zfs_range_compare(const void *arg1, const void *arg2);
+
+#endif /* _KERNEL */
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif	/* _SYS_FS_ZFS_RLOCK_H */