Hi Ted, with <ext4.git#dev> up to commit ab7b179af3f98772f2433ddc4ace6b7924a4e862 ("Merge branch 'hs/fast-commit-v9' into dev") I see some warnings (were reported via kernel-test-bot)... fs/jbd2/recovery.c:241:15: warning: unused variable 'seq' [-Wunused-variable] fs/ext4/fast_commit.c:1091:6: warning: variable 'start_time' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized] fs/ext4/fast_commit.c:1091:6: warning: variable 'start_time' is used uninitialized whenever '||' condition is true [-Wsometimes-uninitialized] ...and more severe a build breakage with CONFIG_JBD2=and CONFIG_EXT4_FS=m ERROR: modpost: "jbd2_fc_release_bufs" [fs/ext4/ext4.ko] undefined! ERROR: modpost: "jbd2_fc_init" [fs/ext4/ext4.ko] undefined! ERROR: modpost: "jbd2_fc_stop_do_commit" [fs/ext4/ext4.ko] undefined! ERROR: modpost: "jbd2_fc_stop" [fs/ext4/ext4.ko] undefined! ERROR: modpost: "jbd2_fc_start" [fs/ext4/ext4.ko] undefined! Looks like missing exports. Regards, - Sedat -