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authorOmar Sandoval <osandov@fb.com>2020-03-02 14:02:49 -0800
committerDavid Sterba <dsterba@suse.com>2020-03-03 15:26:08 +0100
commite7a04894c766daa4248cb736efee93550f2d5872 (patch)
tree500ed1c5e3a81c03d1c70c7c3f3e44e476a154e5
parenta5ae50dea9111db63d30d700766dd5509602f7ad (diff)
btrfs: fix RAID direct I/O reads with alternate csums
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: 1e25a2e3ca0d ("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>
-rw-r--r--fs/btrfs/inode.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 1ccb3f8d528d..27076ebadb36 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7783,6 +7783,7 @@ static inline blk_status_t btrfs_lookup_and_bind_dio_csum(struct inode *inode,
{
struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
struct btrfs_io_bio *orig_io_bio = btrfs_io_bio(dip->orig_bio);
+ u16 csum_size;
blk_status_t ret;
/*
@@ -7802,7 +7803,8 @@ static inline blk_status_t btrfs_lookup_and_bind_dio_csum(struct inode *inode,
file_offset -= dip->logical_offset;
file_offset >>= inode->i_sb->s_blocksize_bits;
- io_bio->csum = (u8 *)(((u32 *)orig_io_bio->csum) + file_offset);
+ csum_size = btrfs_super_csum_size(btrfs_sb(inode->i_sb)->super_copy);
+ io_bio->csum = orig_io_bio->csum + csum_size * file_offset;
return 0;
}