[bug report] fs/ntfs3: mask truncates in ntfs_compress_write()

[bug report] fs/ntfs3: mask truncates in ntfs_compress_write()

[Dan Carpenter]

Hello Konstantin Komarov,

The patch 4342306f0f0d: "fs/ntfs3: Add file operations and
implementation" from Aug 13, 2021, leads to the following
Smatch static checker warning:

	fs/ntfs3/file.c:921 ntfs_compress_write()
	warn: was expecting a 64 bit value instead of '~(frame_size - 1)'

fs/ntfs3/file.c
    871 static ssize_t ntfs_compress_write(struct kiocb *iocb, struct iov_iter *from)
    872 {
    873 	int err;
    874 	struct file *file = iocb->ki_filp;
    875 	size_t count = iov_iter_count(from);
    876 	loff_t pos = iocb->ki_pos;
    877 	struct inode *inode = file_inode(file);
    878 	loff_t i_size = inode->i_size;
    879 	struct address_space *mapping = inode->i_mapping;
    880 	struct ntfs_inode *ni = ntfs_i(inode);
    881 	u64 valid = ni->i_valid;
    882 	struct ntfs_sb_info *sbi = ni->mi.sbi;
    883 	struct page *page, **pages = NULL;
    884 	size_t written = 0;
    885 	u8 frame_bits = NTFS_LZNT_CUNIT + sbi->cluster_bits;
    886 	u32 frame_size = 1u << frame_bits;
    887 	u32 pages_per_frame = frame_size >> PAGE_SHIFT;
    888 	u32 ip, off;
    889 	CLST frame;
    890 	u64 frame_vbo;
    891 	pgoff_t index;
    892 	bool frame_uptodate;
    893 
    894 	if (frame_size < PAGE_SIZE) {
    895 		/*
    896 		 * frame_size == 8K if cluster 512
    897 		 * frame_size == 64K if cluster 4096
    898 		 */
    899 		ntfs_inode_warn(inode, "page size is bigger than frame size");
    900 		return -EOPNOTSUPP;
    901 	}
    902 
    903 	pages = ntfs_malloc(pages_per_frame * sizeof(struct page *));
    904 	if (!pages)
    905 		return -ENOMEM;
    906 
    907 	current->backing_dev_info = inode_to_bdi(inode);
    908 	err = file_remove_privs(file);
    909 	if (err)
    910 		goto out;
    911 
    912 	err = file_update_time(file);
    913 	if (err)
    914 		goto out;
    915 
    916 	/* zero range [valid : pos) */
    917 	while (valid < pos) {
    918 		CLST lcn, clen;
    919 
    920 		frame = valid >> frame_bits;
--> 921 		frame_vbo = valid & ~(frame_size - 1);

valid is u64 but the mask truncates to u32.

    922 		off = valid & (frame_size - 1);
    923 
    924 		err = attr_data_get_block(ni, frame << NTFS_LZNT_CUNIT, 0, &lcn,
    925 					  &clen, NULL);
    926 		if (err)

regards,
dan carpenter