From a0abb062181ad97bffc5011fba6920baeee5152e Mon Sep 17 00:00:00 2001 From: David Sterba Date: Tue, 7 Nov 2017 19:17:41 +0100 Subject: [PATCH] btrfs-progs: docs: add note about mount option applicability Copied from https://btrfs.wiki.kernel.org/index.php/Mount_options . Signed-off-by: David Sterba --- Documentation/btrfs-man5.asciidoc | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Documentation/btrfs-man5.asciidoc b/Documentation/btrfs-man5.asciidoc index bd00533..dd436cd 100644 --- a/Documentation/btrfs-man5.asciidoc +++ b/Documentation/btrfs-man5.asciidoc @@ -26,6 +26,13 @@ This section describes mount options specific to BTRFS. For the generic mount options please refer to `mount`(8) manpage. The options are sorted alphabetically (discarding the 'no' prefix). +NOTE: most mount options apply to the whole filesystem and only options in the +first mounted subvolume will take effect. This is due to lack of implementation +and may change in the future. This means that (for example) you can't set +per-subvolume 'nodatacow', 'nodatasum', or 'compress' using mount options. This +should eventually be fixed, but it has proved to be difficult to implement +correctly within the Linux VFS framework. + *acl*:: *noacl*:: (default: on) -- 2.7.4