ext4: COLLAPSE_RANGE only works on extent-based files

Unfortunately, we weren't checking to make sure of this the inode was
extent-based before attempt operate on it.  Hilarity ensues.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Namjae Jeon <namjae.jeon@samsung.com>

fs/ext4/extents.c

@@ -4878,9 +4878,6 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 	if (mode & FALLOC_FL_PUNCH_HOLE)
 		return ext4_punch_hole(inode, offset, len);
 
-	if (mode & FALLOC_FL_COLLAPSE_RANGE)
-		return ext4_collapse_range(inode, offset, len);
-
 	ret = ext4_convert_inline_data(inode);
 	if (ret)
 		return ret;
@@ -4892,6 +4889,9 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 		return -EOPNOTSUPP;
 
+	if (mode & FALLOC_FL_COLLAPSE_RANGE)
+		return ext4_collapse_range(inode, offset, len);
+
 	if (mode & FALLOC_FL_ZERO_RANGE)
 		return ext4_zero_range(file, offset, len, mode);