On Wed, Oct 31, 2018 at 06:04:36PM +0200, Amir Goldstein wrote: > > Ok. So basically strict and metacopy has no connection but we want to > > take this opportunity to enable more sane overlayfs behavior by default > > without breaking backward compatibility. > > > > And if a corner case user does not like implicit strict=on, they can > > specifically do "metacopy=on,strict=off". > > > > Yes, but keep in mind that strict=off will NOT be applied to stable > v4.19.y *unless* a real user really reports a bug, a-priori, we assume > that implicit metacopy=on => redirect_dir=on,strict=on is sufficient > to solve the bug, so it is sufficient for stable. Did not understand this. So strict=on will be in stable or not? I mean, all the behavior strict=on enforces will be in 4.19 or not. If it is not, then it will become backward compatibility issue by the time 4.20 releases. If strict=on is not part of 4.19 stable, then you can't switch it on in 4.20. What am I missing. > > > I am fine with this. Thanks. > > > > So every new mount option now will enable strict=on implicitly? > > > > Correct. For example: > > > @@ -109,6 +109,7 @@ config OVERLAY_FS_METACOPY > bool "Overlayfs: turn on metadata only copy up feature by default" > depends on OVERLAY_FS > select OVERLAY_FS_REDIRECT_DIR > + select OVERLAY_FS_STRICT > help > If this config option is enabled then overlay filesystems will > copy up only metadata where appropriate and data copy up will > > ... > > @@ -560,6 +599,10 @@ static int ovl_parse_opt(char *opt, struct > ovl_config *config) > } > } > > + /* We must honor user explicit request to enable metacopy */ > + if (config->metacopy && !ovl_metacopy_def) > + config->strict = true; > + So if a user loads module with metacopy=on and also specifies metacopy=on mount option, then strict will not be enforced? Thanks Vivek
