ext4: fix bigalloc regression

Commit f5a44db5d2 introduced a regression on filesystems created with the bigalloc feature (cluster size > blocksize). It causes xfstests generic/006 and /013 to fail with an unexpected JBD2 failure and transaction abort that leaves the test file system in a read only state. Other xfstests run on bigalloc file systems are likely to fail as well.

The cause is the accidental use of a cluster mask where a cluster offset was needed in ext4_ext_map_blocks().

---
 fs/ext4/extents.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 4410cc3..3384dc4 100644
@@ -4218,7 +4218,7 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
 	 */
 	map->m_flags &= ~EXT4_MAP_FROM_CLUSTER;
 	newex.ee_block = cpu_to_le32(map->m_lblk);
-	cluster_offset = EXT4_LBLK_CMASK(sbi, map->m_lblk);
+	cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
 
 	/*
 	 * If we are doing bigalloc, check to see if the extent returned

1.8.3.2

Thanks, applied.

- Ted