fs/ntfs3: Always make file nonresident on fallocate call

xfstest 438 is starting to pass with this change.
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

fs/ntfs3/attrib.c

@@ -2558,3 +2558,35 @@ int attr_insert_range(struct ntfs_inode *ni, u64 vbo, u64 bytes)
 
 	goto out;
 }
+
+/*
+ * attr_force_nonresident
+ *
+ * Convert default data attribute into non resident form.
+ */
+int attr_force_nonresident(struct ntfs_inode *ni)
+{
+	int err;
+	struct ATTRIB *attr;
+	struct ATTR_LIST_ENTRY *le = NULL;
+	struct mft_inode *mi;
+
+	attr = ni_find_attr(ni, NULL, &le, ATTR_DATA, NULL, 0, NULL, &mi);
+	if (!attr) {
+		ntfs_bad_inode(&ni->vfs_inode, "no data attribute");
+		return -ENOENT;
+	}
+
+	if (attr->non_res) {
+		/* Already non resident. */
+		return 0;
+	}
+
+	down_write(&ni->file.run_lock);
+	err = attr_make_nonresident(ni, attr, le, mi,
+				    le32_to_cpu(attr->res.data_size),
+				    &ni->file.run, &attr, NULL);
+	up_write(&ni->file.run_lock);
+
+	return err;
+}

fs/ntfs3/file.c

@@ -578,6 +578,15 @@ static long ntfs_fallocate(struct file *file, int mode, loff_t vbo, loff_t len)
 		/* Check new size. */
 		u8 cluster_bits = sbi->cluster_bits;
 
+		/* Be sure file is non resident. */
+		if (is_resident(ni)) {
+			ni_lock(ni);
+			err = attr_force_nonresident(ni);
+			ni_unlock(ni);
+			if (err)
+				goto out;
+		}
+
 		/* generic/213: expected -ENOSPC instead of -EFBIG. */
 		if (!is_supported_holes) {
 			loff_t to_alloc = new_size - inode_get_bytes(inode);

fs/ntfs3/ntfs_fs.h

@@ -452,6 +452,7 @@ int attr_allocate_frame(struct ntfs_inode *ni, CLST frame, size_t compr_size,
 int attr_collapse_range(struct ntfs_inode *ni, u64 vbo, u64 bytes);
 int attr_insert_range(struct ntfs_inode *ni, u64 vbo, u64 bytes);
 int attr_punch_hole(struct ntfs_inode *ni, u64 vbo, u64 bytes, u32 *frame_size);
+int attr_force_nonresident(struct ntfs_inode *ni);
 
 /* Functions from attrlist.c */
 void al_destroy(struct ntfs_inode *ni);