Hi Namjae: I'm seeing generic/064 fail consistently when testing ext4 on 4.2-rc kernels with Ted's kvm-xfstests test appliance. The two kvm-xfstests test cases that fail are ext3conv and data_journal. Both of them force disablement of delayed allocation. The nodelalloc mount option is used explicitly in the ext3conv case, and it's set implicitly in the kernel when the data_journal mount option is used. The size of the scratch device used also matters. The failure occurs when the device is 5 GB in size, but does not when 20 GB in size. What's happening is that when nodelalloc is set, ext4 produces a testfile.dest containing 101 extents when generic/064 inserts 100 block ranges, and this does not match the test's expected output of 100 extents. Ted Ts'o says that ext4 does not guarantee a specific extent layout when delayed allocation is disabled in these circumstances. The header comment for generic/064 states that insert range is to be called until 100 extents are created. Would the intent of your test be preserved if it was modified to verify that 100 holes were inserted rather than 100 extents created? This would seem to be a more direct way to verify that insert range was functioning correctly without assuming anything about other test filesystem behavior. ext4 does create 100 holes for generic/064 with nodelalloc set. Thanks, Eric -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
