patch-2.4.25 linux-2.4.25/fs/xfs/xfs_behavior.c

• Lines: 219
• Date: 2004-02-18 05:36:32.000000000 -0800
• Orig file: linux-2.4.24/fs/xfs/xfs_behavior.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.24/fs/xfs/xfs_behavior.c linux-2.4.25/fs/xfs/xfs_behavior.c
@@ -0,0 +1,218 @@
+/*
+ * Copyright (c) 2000-2003 Silicon Graphics, Inc.  All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * Further, this software is distributed without any warranty that it is
+ * free of the rightful claim of any third person regarding infringement
+ * or the like.  Any license provided herein, whether implied or
+ * otherwise, applies only to this software file.  Patent licenses, if
+ * any, provided herein do not apply to combinations of this program with
+ * other software, or any other product whatsoever.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write the Free Software Foundation, Inc., 59
+ * Temple Place - Suite 330, Boston MA 02111-1307, USA.
+ *
+ * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
+ * Mountain View, CA  94043, or:
+ *
+ * http://www.sgi.com
+ *
+ * For further information regarding this notice, see:
+ *
+ * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
+ *
+ */
+#include "xfs.h"
+
+/*
+ * Source file used to associate/disassociate behaviors with virtualized
+ * objects.  See xfs_behavior.h for more information about behaviors, etc.
+ *
+ * The implementation is split between functions in this file and macros
+ * in xfs_behavior.h.
+ */
+
+/*
+ * Insert a new behavior descriptor into a behavior chain.
+ *
+ * The behavior chain is ordered based on the 'position' number which
+ * lives in the first field of the ops vector (higher numbers first).
+ *
+ * Attemps to insert duplicate ops result in an EINVAL return code.
+ * Otherwise, return 0 to indicate success.
+ */
+int
+bhv_insert(bhv_head_t *bhp, bhv_desc_t *bdp)
+{
+	bhv_desc_t	*curdesc, *prev;
+	int		position;
+
+	/*
+	 * Validate the position value of the new behavior.
+	 */
+	position = BHV_POSITION(bdp);
+	ASSERT(position >= BHV_POSITION_BASE && position <= BHV_POSITION_TOP);
+
+	/*
+	 * Find location to insert behavior.  Check for duplicates.
+	 */
+	prev = NULL;
+	for (curdesc = bhp->bh_first;
+	     curdesc != NULL;
+	     curdesc = curdesc->bd_next) {
+
+		/* Check for duplication. */
+		if (curdesc->bd_ops == bdp->bd_ops) {
+			ASSERT(0);
+			return EINVAL;
+		}
+
+		/* Find correct position */
+		if (position >= BHV_POSITION(curdesc)) {
+			ASSERT(position != BHV_POSITION(curdesc));
+			break;		/* found it */
+		}
+
+		prev = curdesc;
+	}
+
+	if (prev == NULL) {
+		/* insert at front of chain */
+		bdp->bd_next = bhp->bh_first;
+		bhp->bh_first = bdp;
+	} else {
+		/* insert after prev */
+		bdp->bd_next = prev->bd_next;
+		prev->bd_next = bdp;
+	}
+
+	return 0;
+}
+
+/*
+ * Remove a behavior descriptor from a position in a behavior chain;
+ * the postition is guaranteed not to be the first position.
+ * Should only be called by the bhv_remove() macro.
+ */
+void
+bhv_remove_not_first(bhv_head_t *bhp, bhv_desc_t *bdp)
+{
+	bhv_desc_t	*curdesc, *prev;
+
+	ASSERT(bhp->bh_first != NULL);
+	ASSERT(bhp->bh_first->bd_next != NULL);
+
+	prev = bhp->bh_first;
+	for (curdesc = bhp->bh_first->bd_next;
+	     curdesc != NULL;
+	     curdesc = curdesc->bd_next) {
+
+		if (curdesc == bdp)
+			break;		/* found it */
+		prev = curdesc;
+	}
+
+	ASSERT(curdesc == bdp);
+	prev->bd_next = bdp->bd_next;	/* remove from after prev */
+}
+
+/*
+ * Look for a specific ops vector on the specified behavior chain.
+ * Return the associated behavior descriptor.  Or NULL, if not found.
+ */
+bhv_desc_t *
+bhv_lookup(bhv_head_t *bhp, void *ops)
+{
+	bhv_desc_t	*curdesc;
+
+	for (curdesc = bhp->bh_first;
+	     curdesc != NULL;
+	     curdesc = curdesc->bd_next) {
+
+		if (curdesc->bd_ops == ops)
+			return curdesc;
+	}
+
+	return NULL;
+}
+
+/*
+ * Looks for the first behavior within a specified range of positions.
+ * Return the associated behavior descriptor.  Or NULL, if none found.
+ */
+bhv_desc_t *
+bhv_lookup_range(bhv_head_t *bhp, int low, int high)
+{
+	bhv_desc_t	*curdesc;
+
+	for (curdesc = bhp->bh_first;
+	     curdesc != NULL;
+	     curdesc = curdesc->bd_next) {
+
+		int	position = BHV_POSITION(curdesc);
+
+		if (position <= high) {
+			if (position >= low)
+				return curdesc;
+			return NULL;
+		}
+	}
+
+	return NULL;
+}
+
+/*
+ * Return the base behavior in the chain, or NULL if the chain
+ * is empty.
+ *
+ * The caller has not read locked the behavior chain, so acquire the
+ * lock before traversing the chain.
+ */
+bhv_desc_t *
+bhv_base(bhv_head_t *bhp)
+{
+	bhv_desc_t	*curdesc;
+
+	for (curdesc = bhp->bh_first;
+	     curdesc != NULL;
+	     curdesc = curdesc->bd_next) {
+
+		if (curdesc->bd_next == NULL) {
+			return curdesc;
+		}
+	}
+
+	return NULL;
+}
+
+void
+bhv_head_init(
+	bhv_head_t *bhp,
+	char *name)
+{
+	bhp->bh_first = NULL;
+}
+
+void
+bhv_insert_initial(
+	bhv_head_t *bhp,
+	bhv_desc_t *bdp)
+{
+	ASSERT(bhp->bh_first == NULL);
+	(bhp)->bh_first = bdp;
+}
+
+void
+bhv_head_destroy(
+	bhv_head_t *bhp)
+{
+	ASSERT(bhp->bh_first == NULL);
+}