On Thu, Dec 26, 2013 at 02:45:10PM +0800, Qu Wenruo wrote: > Btrfs can be remounted without barrier, but there is no "barrier" option > so nobody can remount btrfs back with barrier on. Only umount and > mount again can re-enable barrier.(Quite awkward) Ok for adding the mount option. > Reported-by: Daniel Blueman <daniel@xxxxxxxxx> > Signed-off-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx> > --- > Documentation/filesystems/btrfs.txt | 6 ++++++ > fs/btrfs/super.c | 8 +++++++- > 2 files changed, 13 insertions(+), 1 deletion(-) > > diff --git a/Documentation/filesystems/btrfs.txt b/Documentation/filesystems/btrfs.txt > index 5dd282d..f6f71d6 100644 > --- a/Documentation/filesystems/btrfs.txt > +++ b/Documentation/filesystems/btrfs.txt > @@ -51,6 +51,12 @@ Unless otherwise specified, all options default to off. > defrag process. Works best for small files; Not well suited for > large database workloads. > > + barrier > + Enable the use of block layer write barriers. Write barriers ensure > + that certain IOs make it through the device cache and are on persistent > + storage. > + Barriers are enabled by default. There's the 'nobarrier' option already, I think it's better to keep the pairing option documentation at one place and mark the default one with (*). Related to that, there should imho be a pairing option for every mount option where it makes sense, so all the combinations work through remount. The defaults do not need to be listed via btrfs_show_options, ie. keep the output same as it is now. david -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
