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Oliver Paukstadt from our test department is testing the xip patches in Linus' git-tree. He found a problem that shows when reading a file that contains sparse blocks (holes) on a -o xip mounted ext2 filesystem: the BUG_ON() in fs/ext2/xip.c:40 triggers where it should not. The problem was introduced by a cleanup in my previous patch, this patch fixes it. 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>
94 lines
2.0 KiB
C
94 lines
2.0 KiB
C
/*
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* linux/fs/ext2/xip.c
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*
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* Copyright (C) 2005 IBM Corporation
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* Author: Carsten Otte (cotte@de.ibm.com)
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*/
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#include <linux/mm.h>
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#include <linux/fs.h>
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#include <linux/genhd.h>
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#include <linux/buffer_head.h>
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#include <linux/ext2_fs_sb.h>
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#include <linux/ext2_fs.h>
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#include "ext2.h"
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#include "xip.h"
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static inline int
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__inode_direct_access(struct inode *inode, sector_t sector,
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unsigned long *data)
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{
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BUG_ON(!inode->i_sb->s_bdev->bd_disk->fops->direct_access);
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return inode->i_sb->s_bdev->bd_disk->fops
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->direct_access(inode->i_sb->s_bdev,sector,data);
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}
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static inline int
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__ext2_get_sector(struct inode *inode, sector_t offset, int create,
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sector_t *result)
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{
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struct buffer_head tmp;
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int rc;
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memset(&tmp, 0, sizeof(struct buffer_head));
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rc = ext2_get_block(inode, offset/ (PAGE_SIZE/512), &tmp,
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create);
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*result = tmp.b_blocknr;
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/* did we get a sparse block (hole in the file)? */
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if (!tmp.b_blocknr && !rc) {
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BUG_ON(create);
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rc = -ENODATA;
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}
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return rc;
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}
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int
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ext2_clear_xip_target(struct inode *inode, int block)
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{
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sector_t sector = block * (PAGE_SIZE/512);
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unsigned long data;
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int rc;
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rc = __inode_direct_access(inode, sector, &data);
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if (!rc)
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clear_page((void*)data);
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return rc;
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}
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void ext2_xip_verify_sb(struct super_block *sb)
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{
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struct ext2_sb_info *sbi = EXT2_SB(sb);
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if ((sbi->s_mount_opt & EXT2_MOUNT_XIP) &&
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!sb->s_bdev->bd_disk->fops->direct_access) {
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sbi->s_mount_opt &= (~EXT2_MOUNT_XIP);
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ext2_warning(sb, __FUNCTION__,
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"ignoring xip option - not supported by bdev");
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}
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}
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struct page *
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ext2_get_xip_page(struct address_space *mapping, sector_t offset,
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int create)
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{
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int rc;
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unsigned long data;
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sector_t sector;
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/* first, retrieve the sector number */
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rc = __ext2_get_sector(mapping->host, offset, create, §or);
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if (rc)
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goto error;
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/* retrieve address of the target data */
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rc = __inode_direct_access
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(mapping->host, sector * (PAGE_SIZE/512), &data);
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if (!rc)
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return virt_to_page(data);
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error:
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return ERR_PTR(rc);
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}
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