On 4/12/11 1:04 PM, Johann Lombardi wrote: > Prevent an ext4 filesystem from being mounted multiple times. > A sequence number is stored on disk and is periodically updated (every 5 > seconds by default) by a mounted filesystem. > At mount time, we now wait for s_mmp_update_interval seconds to make sure > that the MMP sequence does not change. > In case of failure, the nodename, bdevname and the time at which the MMP > block was last updated is displayed. > > Signed-off-by: Andreas Dilger <adilger@xxxxxxxxxxxxx> > Signed-off-by: Johann Lombardi <johann@xxxxxxxxxxxxx> > --- > fs/ext4/ext4.h | 56 ++++++++- > fs/ext4/super.c | 363 ++++++++++++++++++++++++++++++++++++++++++++++++++++++- > 2 files changed, 416 insertions(+), 3 deletions(-) > There was a lot of skepticism about this last time, and I imagine there still is... 400 new lines of kernel code for this, and if the other machine is hung up for 5 seconds and doesn't update, it can still be multiply-mounted anyway, right? BUG: soft lockup - CPU#0 stuck for 10s! anyone? :( I don't see the value in it for upstream ext4, but then hey, ext4 rarely meets a feature it doesn't like ;) -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
