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7ba3ec5749
Commit 8e3dffc651 "Ext2: mark inode dirty after the function
dquot_free_block_nodirty is called" unveiled a bug in __ext2_get_block()
called from ext2_get_xip_mem(). That function called ext2_get_block()
mistakenly asking it to map 0 blocks while 1 was intended. Before the
above mentioned commit things worked out fine by luck but after that commit
we started returning that we allocated 0 blocks while we in fact
allocated 1 block and thus allocation was looping until all blocks in
the filesystem were exhausted.
Fix the problem by properly asking for one block and also add assertion
in ext2_get_blocks() to catch similar problems.
Reported-and-tested-by: Andiry Xu <andiry.xu@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
92 lines
2.0 KiB
C
92 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/blkdev.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 block,
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void **kaddr, unsigned long *pfn)
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{
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struct block_device *bdev = inode->i_sb->s_bdev;
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const struct block_device_operations *ops = bdev->bd_disk->fops;
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sector_t sector;
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sector = block * (PAGE_SIZE / 512); /* ext2 block to bdev sector */
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BUG_ON(!ops->direct_access);
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return ops->direct_access(bdev, sector, kaddr, pfn);
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}
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static inline int
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__ext2_get_block(struct inode *inode, pgoff_t pgoff, 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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tmp.b_size = 1 << inode->i_blkbits;
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rc = ext2_get_block(inode, pgoff, &tmp, 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, sector_t block)
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{
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void *kaddr;
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unsigned long pfn;
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int rc;
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rc = __inode_direct_access(inode, block, &kaddr, &pfn);
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if (!rc)
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clear_page(kaddr);
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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_msg(sb, KERN_WARNING,
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"warning: ignoring xip option - "
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"not supported by bdev");
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}
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}
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int ext2_get_xip_mem(struct address_space *mapping, pgoff_t pgoff, int create,
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void **kmem, unsigned long *pfn)
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{
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int rc;
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sector_t block;
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/* first, retrieve the sector number */
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rc = __ext2_get_block(mapping->host, pgoff, create, &block);
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if (rc)
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return rc;
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/* retrieve address of the target data */
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rc = __inode_direct_access(mapping->host, block, kmem, pfn);
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return rc;
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}
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