/* * 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); }