Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

1 files changed, 139 insertions, 0 deletions

diff --git a/fs/btrfs/struct-funcs.c b/fs/btrfs/struct-funcs.c
new file mode 100644
index 00000000000..c0f7ecaf1e7
--- /dev/null
+++ b/fs/btrfs/struct-funcs.c
@@ -0,0 +1,139 @@
+/*
+ * Copyright (C) 2007 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * 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, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/highmem.h>
+
+/* this is some deeply nasty code.  ctree.h has a different
+ * definition for this BTRFS_SETGET_FUNCS macro, behind a #ifndef
+ *
+ * The end result is that anyone who #includes ctree.h gets a
+ * declaration for the btrfs_set_foo functions and btrfs_foo functions
+ *
+ * This file declares the macros and then #includes ctree.h, which results
+ * in cpp creating the function here based on the template below.
+ *
+ * These setget functions do all the extent_buffer related mapping
+ * required to efficiently read and write specific fields in the extent
+ * buffers.  Every pointer to metadata items in btrfs is really just
+ * an unsigned long offset into the extent buffer which has been
+ * cast to a specific type.  This gives us all the gcc type checking.
+ *
+ * The extent buffer api is used to do all the kmapping and page
+ * spanning work required to get extent buffers in highmem and have
+ * a metadata blocksize different from the page size.
+ *
+ * The macro starts with a simple function prototype declaration so that
+ * sparse won't complain about it being static.
+ */
+
+#define BTRFS_SETGET_FUNCS(name, type, member, bits)			\
+u##bits btrfs_##name(struct extent_buffer *eb, type *s);		\
+void btrfs_set_##name(struct extent_buffer *eb, type *s, u##bits val);	\
+u##bits btrfs_##name(struct extent_buffer *eb,				\
+				   type *s)				\
+{									\
+	unsigned long part_offset = (unsigned long)s;			\
+	unsigned long offset = part_offset + offsetof(type, member);	\
+	type *p;							\
+	/* ugly, but we want the fast path here */			\
+	if (eb->map_token && offset >= eb->map_start &&			\
+	    offset + sizeof(((type *)0)->member) <= eb->map_start +	\
+	    eb->map_len) {						\
+		p = (type *)(eb->kaddr + part_offset - eb->map_start);	\
+		return le##bits##_to_cpu(p->member);			\
+	}								\
+	{								\
+		int err;						\
+		char *map_token;					\
+		char *kaddr;						\
+		int unmap_on_exit = (eb->map_token == NULL);		\
+		unsigned long map_start;				\
+		unsigned long map_len;					\
+		u##bits res;						\
+		err = map_extent_buffer(eb, offset,			\
+				sizeof(((type *)0)->member),		\
+				&map_token, &kaddr,			\
+				&map_start, &map_len, KM_USER1);	\
+		if (err) {						\
+			__le##bits leres;				\
+			read_eb_member(eb, s, type, member, &leres);	\
+			return le##bits##_to_cpu(leres);		\
+		}							\
+		p = (type *)(kaddr + part_offset - map_start);		\
+		res = le##bits##_to_cpu(p->member);			\
+		if (unmap_on_exit)					\
+			unmap_extent_buffer(eb, map_token, KM_USER1);	\
+		return res;						\
+	}								\
+}									\
+void btrfs_set_##name(struct extent_buffer *eb,				\
+				    type *s, u##bits val)		\
+{									\
+	unsigned long part_offset = (unsigned long)s;			\
+	unsigned long offset = part_offset + offsetof(type, member);	\
+	type *p;							\
+	/* ugly, but we want the fast path here */			\
+	if (eb->map_token && offset >= eb->map_start &&			\
+	    offset + sizeof(((type *)0)->member) <= eb->map_start +	\
+	    eb->map_len) {						\
+		p = (type *)(eb->kaddr + part_offset - eb->map_start);	\
+		p->member = cpu_to_le##bits(val);			\
+		return;							\
+	}								\
+	{								\
+		int err;						\
+		char *map_token;					\
+		char *kaddr;						\
+		int unmap_on_exit = (eb->map_token == NULL);		\
+		unsigned long map_start;				\
+		unsigned long map_len;					\
+		err = map_extent_buffer(eb, offset,			\
+				sizeof(((type *)0)->member),		\
+				&map_token, &kaddr,			\
+				&map_start, &map_len, KM_USER1);	\
+		if (err) {						\
+			__le##bits val2;				\
+			val2 = cpu_to_le##bits(val);			\
+			write_eb_member(eb, s, type, member, &val2);	\
+			return;						\
+		}							\
+		p = (type *)(kaddr + part_offset - map_start);		\
+		p->member = cpu_to_le##bits(val);			\
+		if (unmap_on_exit)					\
+			unmap_extent_buffer(eb, map_token, KM_USER1);	\
+	}								\
+}
+
+#include "ctree.h"
+
+void btrfs_node_key(struct extent_buffer *eb,
+		    struct btrfs_disk_key *disk_key, int nr)
+{
+	unsigned long ptr = btrfs_node_key_ptr_offset(nr);
+	if (eb->map_token && ptr >= eb->map_start &&
+	    ptr + sizeof(*disk_key) <= eb->map_start + eb->map_len) {
+		memcpy(disk_key, eb->kaddr + ptr - eb->map_start,
+			sizeof(*disk_key));
+		return;
+	} else if (eb->map_token) {
+		unmap_extent_buffer(eb, eb->map_token, KM_USER1);
+		eb->map_token = NULL;
+	}
+	read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
+		       struct btrfs_key_ptr, key, disk_key);
+}