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- /*
- * 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, §or);
- 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);
- }
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