Theodore Tso wrote: > On Mon, May 19, 2008 at 01:32:53PM +0200, Bas van Schaik wrote: > >> Does this tell you anything? >> >> > > Unfortunately comparing the two dumpe2fs outputs don't show anything > interesting. It did rule out a few cases where e2fsck can silently > mark the filesystem has having been modified (setting the directory > hash hint, moving the journal inode, which it does silently without > informing the user --- and I should fix that one of these days; I'll > create some bug reports to remind myself they need to be fixed), but I > don't see why it happened for your case. > > It's definitely not normal; doing a journal replay does not cause fsck > to exit with a non-zero status, if it didn't make any other changes. > I just tested that with e2fsprogs 1.40.8 just in case something had > gotten screwed up, and it worked as expected. > Actually I also wouldn't expect e2fsck to do so. Maybe I'm overseeing something really stupid, this is the bash code I'm running: > e2fsck.static -f -y -v /dev/loop1 &> $TMPLOGFILE > retcode="$?" > > (...) > > if [ ! "$retcode" = "0" ]; then > echo "e2fsck had nonzero exitcode $retcode, aborting!" > (...) > fi > I know how to debug it if you are really motiviated to get to the > bottom of this. It would involve running a modified e2fsck/e2fsprogs > which changes ext2fs_mark_changed() and ext2fs_mark_super_dirty() to > be real functions, and setting breakpoints in gdb so we can trap any > calls made to those functions and dump out a stack backtrace, and then > continuing the e2fsck run, and then reporting to me the stack > backtraces where gdb trapped calls to ext2fs_mark_changed() and/or > ext2fs_mark_super_dirty(). > To be honest, I'm currently trying to find out the cause of all these filesystem corruptions. Maybe I'll try to sort this out later using gdb and so on. > Andreas is right though that if you are taking a proper snapshot, the > disk really should be quiesced and no journal replay should be > required at all. That's how a devicemapper snapshot works in LVM --- > so one good question to explore is how *are* you doing your snapshots. Exactly my thoughts, but apparently something is wrong here too. Maybe I should note that my journal commit interval is set to something like 5 or 10 seconds, is that relevant? Again a small snippet of bash responsible for snapshotting: > snapshot_stamp=`date +%Y%m%d-%H%M%S` > lvcreate --snapshot --size 50G --name backups-snapshot-$snapshot_stamp > $LV &> $TMPLOGFILE This is not a weird way to snapshot, is it? -- Bas -- 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
