btrfs: fix RAID direct I/O reads with alternate csums
commite7a04894c7
upstream. btrfs_lookup_and_bind_dio_csum() does pointer arithmetic which assumes 32-bit checksums. If using a larger checksum, this leads to spurious failures when a direct I/O read crosses a stripe. This is easy to reproduce: # mkfs.btrfs -f --checksum blake2 -d raid0 /dev/vdc /dev/vdd ... # mount /dev/vdc /mnt # cd /mnt # dd if=/dev/urandom of=foo bs=1M count=1 status=none # dd if=foo of=/dev/null bs=1M iflag=direct status=none dd: error reading 'foo': Input/output error # dmesg | tail -1 [ 135.821568] BTRFS warning (device vdc): csum failed root 5 ino 257 off 421888 ... Fix it by using the actual checksum size. Fixes:1e25a2e3ca
("btrfs: don't assume ordered sums to be 4 bytes") CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -8426,6 +8426,7 @@ static inline blk_status_t btrfs_lookup_and_bind_dio_csum(struct inode *inode,
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{
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struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
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struct btrfs_io_bio *orig_io_bio = btrfs_io_bio(dip->orig_bio);
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u16 csum_size;
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blk_status_t ret;
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/*
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@ -8445,7 +8446,8 @@ static inline blk_status_t btrfs_lookup_and_bind_dio_csum(struct inode *inode,
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file_offset -= dip->logical_offset;
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file_offset >>= inode->i_sb->s_blocksize_bits;
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io_bio->csum = (u8 *)(((u32 *)orig_io_bio->csum) + file_offset);
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csum_size = btrfs_super_csum_size(btrfs_sb(inode->i_sb)->super_copy);
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io_bio->csum = orig_io_bio->csum + csum_size * file_offset;
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return 0;
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}
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