For always COW inodes we also must check the alignment of each individual iovec segment, as they could end up with different I/Os due to the way bio_iov_iter_get_pages works, and we'd then overwrite an already written block. Signed-off-by: Christoph Hellwig <hch@xxxxxx> --- fs/xfs/xfs_file.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 2b6d4c71994d..6bcfd4c34a37 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -721,7 +721,16 @@ xfs_file_dio_write( /* direct I/O must be aligned to device logical sector size */ if ((iocb->ki_pos | count) & target->bt_logical_sectormask) return -EINVAL; - if ((iocb->ki_pos | count) & ip->i_mount->m_blockmask) + + /* + * For always COW inodes we also must check the alignment of each + * individual iovec segment, as they could end up with different + * I/Os due to the way bio_iov_iter_get_pages works, and we'd + * then overwrite an already written block. + */ + if (((iocb->ki_pos | count) & ip->i_mount->m_blockmask) || + (xfs_is_always_cow_inode(ip) && + (iov_iter_alignment(from) & ip->i_mount->m_blockmask))) return xfs_file_dio_write_unaligned(ip, iocb, from); return xfs_file_dio_write_aligned(ip, iocb, from); } -- 2.45.2
