This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / fs / ext2 / xip.c

diff --git a/fs/ext2/xip.c b/fs/ext2/xip.c
new file mode 100644 (file)
index 0000000..ca7f003
--- /dev/null
+++ b/fs/ext2/xip.c
@@ -0,0 +1,93 @@
+/*
+ *  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);
+}
+
+static inline int
+__ext2_get_sector(struct inode *inode, sector_t offset, int create,
+                  sector_t *result)
+{
+       struct buffer_head tmp;
+       int rc;
+
+       memset(&tmp, 0, sizeof(struct buffer_head));
+       rc = ext2_get_block(inode, offset/ (PAGE_SIZE/512), &tmp,
+                           create);
+       *result = tmp.b_blocknr;
+
+       /* did we get a sparse block (hole in the file)? */
+       if (!tmp.b_blocknr && !rc) {
+               BUG_ON(create);
+               rc = -ENODATA;
+       }
+
+       return rc;
+}
+
+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)
+               clear_page((void*)data);
+       return rc;
+}
+
+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) &&
+           !sb->s_bdev->bd_disk->fops->direct_access) {
+               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 offset,
+                  int create)
+{
+       int rc;
+       unsigned long data;
+       sector_t sector;
+
+       /* first, retrieve the sector number */
+       rc = __ext2_get_sector(mapping->host, offset, create, &sector);
+       if (rc)
+               goto error;
+
+       /* retrieve address of the target data */
+       rc = __inode_direct_access
+               (mapping->host, sector * (PAGE_SIZE/512), &data);
+       if (!rc)
+               return virt_to_page(data);
+
+ error:
+       return ERR_PTR(rc);
+}