From 842bef5891aaf13e2dede01d86397d810fde2dd8 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Mon, 6 Jan 2014 09:58:25 +0800 Subject: btrfs: Add "barrier" option to support "-o remount,barrier" 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) Also the mount options in the document is also changed slightly for the further pairing options changes. Reported-by: Daniel Blueman Signed-off-by: Qu Wenruo Signed-off-by: Mike Fleetwood Reviewed-by: David Sterba Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- Documentation/filesystems/btrfs.txt | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'Documentation') diff --git a/Documentation/filesystems/btrfs.txt b/Documentation/filesystems/btrfs.txt index 5dd282dda55c..ce487a2a88f8 100644 --- a/Documentation/filesystems/btrfs.txt +++ b/Documentation/filesystems/btrfs.txt @@ -38,7 +38,7 @@ Mount Options ============= When mounting a btrfs filesystem, the following option are accepted. -Unless otherwise specified, all options default to off. +Options with (*) are default options and will not show in the mount options. alloc_start= Debugging option to force all block allocations above a certain @@ -138,12 +138,13 @@ Unless otherwise specified, all options default to off. Disable support for Posix Access Control Lists (ACLs). See the acl(5) manual page for more information about ACLs. + barrier(*) nobarrier - Disables the use of block layer write barriers. Write barriers ensure - that certain IOs make it through the device cache and are on persistent - storage. If used on a device with a volatile (non-battery-backed) - write-back cache, this option will lead to filesystem corruption on a - system crash or power loss. + Enable/disable the use of block layer write barriers. Write barriers + ensure that certain IOs make it through the device cache and are on + persistent storage. If disabled on a device with a volatile + (non-battery-backed) write-back cache, nobarrier option will lead to + filesystem corruption on a system crash or power loss. nodatacow Disable data copy-on-write for newly created files. Implies nodatasum, -- cgit v1.2.3