On Aug 26, 2008 13:04 -0400, Theodore Ts'o wrote: > On Tue, Aug 26, 2008 at 04:45:02AM -0600, Andreas Dilger wrote: > > Running e2fsck on a quiescent (but mounted) filesystem fails in the > > common case where the superblock inode and block count summaries are > > wrong. The kernel doesn't update these values except at unmount time. > > If there are other errors in the filesystem then they will already > > cause e2fsck to consider the filesystem invalid, so these minor errors > > should not. > > Sure, but *when* would it ever be safe to run e2fsck without -n on a > mounted filesystem? What's the scenario where this would matter? And > on an unmounted filesystem, if the block counts are wrong, and the > user refuses to fix them the filesystem technically really isn't 100% > valid. I mean that this is for "e2fsck -fn". In that case the filesystem isn't changed, and is often completely clean except the superblock counters. Until we have block-device freeze ioctl widely available (or convince users to use LVM), the best we can do is quiesce Lustre IO without unmounting the filesystem. Without patch: # e2fsck -fn /dev/hda3 e2fsck 1.40.7.sun1 (28-Feb-2008) Warning! /dev/hda3 is mounted. Warning: skipping journal recovery because doing a read-only filesystem check. Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Pass 5: Checking group summary information Free blocks count wrong (213908, counted=213298). Fix? no Free inodes count wrong (249992, counted=249282). Fix? no lustre-MDT0000: ********** WARNING: Filesystem still has errors ********** lustre-MDT0000: 56/250048 files (17.9% non-contiguous), 36092/250000 blocks # echo $? 4 With patch: # e2fsck -fn /dev/hda3 e2fsck 1.40.11.sun1 (17-June-2008) Warning! /dev/hda3 is mounted. Warning: skipping journal recovery because doing a read-only filesystem check. Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Pass 5: Checking group summary information Free blocks count wrong (213908, counted=213298). Fix? no Free inodes count wrong (249992, counted=249282). Fix? no lustre-MDT0000: 56/250048 files (17.9% non-contiguous), 36092/250000 blocks # echo $? 0 Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc. -- 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