forked from Minki/linux
0ab7620a0c
The MINIX filesystem driver used a constant number of indirect block
pointers in an indirect block. This worked only for filesystems with 1kb
block, while the MINIX default block size is now 4kb. As a consequence,
large files were read incorrectly on such filesystems and writing a
large file would cause the filesystem to become corrupted. This patch
computes the number of indirect block pointers based on the block size,
making the driver work for each block size.
I would like to thank Feiran Zheng ('Fam') for pointing out the cause
of the corruption.
Signed-off-by: Erik van der Kouwe <vdkouwe@cs.vu.nl>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
76 lines
1.9 KiB
C
76 lines
1.9 KiB
C
#include <linux/buffer_head.h>
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#include "minix.h"
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enum {DIRECT = 7, DEPTH = 4}; /* Have triple indirect */
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typedef u32 block_t; /* 32 bit, host order */
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static inline unsigned long block_to_cpu(block_t n)
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{
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return n;
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}
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static inline block_t cpu_to_block(unsigned long n)
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{
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return n;
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}
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static inline block_t *i_data(struct inode *inode)
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{
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return (block_t *)minix_i(inode)->u.i2_data;
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}
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#define DIRCOUNT 7
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#define INDIRCOUNT(sb) (1 << ((sb)->s_blocksize_bits - 2))
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static int block_to_path(struct inode * inode, long block, int offsets[DEPTH])
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{
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int n = 0;
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char b[BDEVNAME_SIZE];
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struct super_block *sb = inode->i_sb;
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if (block < 0) {
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printk("MINIX-fs: block_to_path: block %ld < 0 on dev %s\n",
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block, bdevname(sb->s_bdev, b));
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} else if (block >= (minix_sb(inode->i_sb)->s_max_size/sb->s_blocksize)) {
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if (printk_ratelimit())
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printk("MINIX-fs: block_to_path: "
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"block %ld too big on dev %s\n",
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block, bdevname(sb->s_bdev, b));
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} else if (block < DIRCOUNT) {
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offsets[n++] = block;
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} else if ((block -= DIRCOUNT) < INDIRCOUNT(sb)) {
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offsets[n++] = DIRCOUNT;
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offsets[n++] = block;
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} else if ((block -= INDIRCOUNT(sb)) < INDIRCOUNT(sb) * INDIRCOUNT(sb)) {
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offsets[n++] = DIRCOUNT + 1;
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offsets[n++] = block / INDIRCOUNT(sb);
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offsets[n++] = block % INDIRCOUNT(sb);
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} else {
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block -= INDIRCOUNT(sb) * INDIRCOUNT(sb);
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offsets[n++] = DIRCOUNT + 2;
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offsets[n++] = (block / INDIRCOUNT(sb)) / INDIRCOUNT(sb);
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offsets[n++] = (block / INDIRCOUNT(sb)) % INDIRCOUNT(sb);
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offsets[n++] = block % INDIRCOUNT(sb);
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}
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return n;
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}
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#include "itree_common.c"
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int V2_minix_get_block(struct inode * inode, long block,
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struct buffer_head *bh_result, int create)
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{
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return get_block(inode, block, bh_result, create);
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}
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void V2_minix_truncate(struct inode * inode)
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{
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truncate(inode);
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}
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unsigned V2_minix_blocks(loff_t size, struct super_block *sb)
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{
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return nblocks(size, sb);
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}
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