[PATCH] xip: ext2: execute in place

These are the ext2 related parts.  Ext2 now uses the xip_* file operations
along with the get_xip_page aop when mounted with -o xip.

Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 80 insertions, 0 deletions

diff --git a/fs/ext2/xip.c b/fs/ext2/xip.c
new file mode 100644
index 0000000..d44431d
--- /dev/null
+++ b/fs/ext2/xip.c
@@ -0,0 +1,80 @@
+/*
+ *  linux/fs/ext2/xip.c
+ *
+ * Copyright (C) 2005 IBM Corporation
+ * Author: Carsten Otte (cotte@de.ibm.com)
+ */
+
+#include <linux/mm.h>
+#include <linux/fs.h>
+#include <linux/genhd.h>
+#include <linux/buffer_head.h>
+#include <linux/ext2_fs_sb.h>
+#include <linux/ext2_fs.h>
+#include "ext2.h"
+#include "xip.h"
+
+static inline int
+__inode_direct_access(struct inode *inode, sector_t sector, unsigned long *data) {
+	BUG_ON(!inode->i_sb->s_bdev->bd_disk->fops->direct_access);
+	return inode->i_sb->s_bdev->bd_disk->fops
+		->direct_access(inode->i_sb->s_bdev,sector,data);
+}
+
+int
+ext2_clear_xip_target(struct inode *inode, int block) {
+	sector_t sector = block*(PAGE_SIZE/512);
+	unsigned long data;
+	int rc;
+
+	rc = __inode_direct_access(inode, sector, &data);
+	if (rc)
+		return rc;
+	clear_page((void*)data);
+	return 0;
+}
+
+void ext2_xip_verify_sb(struct super_block *sb)
+{
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+
+	if ((sbi->s_mount_opt & EXT2_MOUNT_XIP)) {
+		if ((sb->s_bdev == NULL) ||
+			sb->s_bdev->bd_disk == NULL ||
+			sb->s_bdev->bd_disk->fops == NULL ||
+			sb->s_bdev->bd_disk->fops->direct_access == NULL) {
+			sbi->s_mount_opt &= (~EXT2_MOUNT_XIP);
+			ext2_warning(sb, __FUNCTION__,
+				"ignoring xip option - not supported by bdev");
+		}
+	}
+}
+
+struct page*
+ext2_get_xip_page(struct address_space *mapping, sector_t blockno,
+		   int create)
+{
+	int rc;
+	unsigned long data;
+	struct buffer_head tmp;
+
+	tmp.b_state = 0;
+	tmp.b_blocknr = 0;
+	rc = ext2_get_block(mapping->host, blockno/(PAGE_SIZE/512) , &tmp,
+				create);
+	if (rc)
+		return ERR_PTR(rc);
+	if (tmp.b_blocknr == 0) {
+		/* SPARSE block */
+		BUG_ON(create);
+		return ERR_PTR(-ENODATA);
+	}
+
+	rc = __inode_direct_access
+		(mapping->host,tmp.b_blocknr*(PAGE_SIZE/512) ,&data);
+	if (rc)
+		return ERR_PTR(rc);
+
+	SetPageUptodate(virt_to_page(data));
+	return virt_to_page(data);
+}