ext2fs: Fix optimization bug for doubly-indirect block pointers

Doubly-indirect block numbers are compared against the first-level
indirect block when checking for a cached copy.  This is causing the
doubly-indirect block to be re-read each time it is accessed.
Repairing this reduces load time for a 70M file from 72 seconds
to 38 seconds.

Signed-off-by: Aaron Pace <Aaron.Pace@alcatel-lucent.com>

fs/ext2/ext2fs.c

@@ -364,7 +364,7 @@ static int ext2fs_read_block (ext2fs_node_t node, int fileblock) {
 			indir2_size = blksz;
 		}
 		if ((__le32_to_cpu (indir1_block[rblock / perblock]) <<
-		     log2_blksz) != indir1_blkno) {
+		     log2_blksz) != indir2_blkno) {
 			status = ext2fs_devread (__le32_to_cpu(indir1_block[rblock / perblock]) << log2_blksz,
 						 0, blksz,
 						 (char *) indir2_block);