In an dedupe corporation iter loop, the length of iomap_iter decreases because it implies the remaining length after each iteration. The compare function should use the min length of the current iters, not the total length. Fixes: 0e79e3736d54 ("fsdax: dedupe: iter two files at the same time") Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx> --- fs/dax.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index 3e457a16c7d1..9800b93ee14d 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -2022,8 +2022,8 @@ int dax_dedupe_file_range_compare(struct inode *src, loff_t srcoff, while ((ret = iomap_iter(&src_iter, ops)) > 0 && (ret = iomap_iter(&dst_iter, ops)) > 0) { - compared = dax_range_compare_iter(&src_iter, &dst_iter, len, - same); + compared = dax_range_compare_iter(&src_iter, &dst_iter, + min(src_iter.len, dst_iter.len), same); if (compared < 0) return ret; src_iter.processed = dst_iter.processed = compared; -- 2.39.2