From 0f1f4e7278c1bc93d54da1026dfe484f27bcd873 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 26 Feb 2015 14:10:35 -0500 Subject: exports.man: improve documentation of 'nohide' and 'crossmnt' - note that 'nohide' is irrelevant for NFSv4 - note that children on a 'crossmnt' filesystem cannot be unexported - note that 'nocrossmnt' is a valid option, but probably not useful. Signed-off-by: NeilBrown Signed-off-by: Steve Dickson --- utils/exportfs/exports.man | 42 ++++++++++++++++++++++++++++++++++++------ 1 file changed, 36 insertions(+), 6 deletions(-) diff --git a/utils/exportfs/exports.man b/utils/exportfs/exports.man index 3d974d9..88d9fbe 100644 --- a/utils/exportfs/exports.man +++ b/utils/exportfs/exports.man @@ -218,16 +218,46 @@ This option can be very useful in some situations, but it should be used with due care, and only after confirming that the client system copes with the situation effectively. -The option can be explicitly disabled with +The option can be explicitly disabled for NFSv2 and NFSv3 with .IR hide . + +This option is not relevant when NFSv4 is use. NFSv4 never hides +subordinate filesystems. Any filesystem that is exported will be +visible where expected when using NFSv4. .TP -.IR crossmnt +.I crossmnt This option is similar to .I nohide -but it makes it possible for clients to move from the filesystem marked -with crossmnt to exported filesystems mounted on it. Thus when a child -filesystem "B" is mounted on a parent "A", setting crossmnt on "A" has -the same effect as setting "nohide" on B. +but it makes it possible for clients to access all filesystems mounted +on a filesystem marked with +.IR crossmnt . +Thus when a child filesystem "B" is mounted on a parent "A", setting +crossmnt on "A" has a similar effect to setting "nohide" on B. + +With +.I nohide +the child filesystem needs to be explicitly exported. With +.I crossmnt +it need not. If a child of a +.I crossmnt +file is not explicitly exported, then it will be implicitly exported +with the same export options as the parent, except for +.IR fsid= . +This makes it impossible to +.B not +export a child of a +.I crossmnt +filesystem. If some but not all subordinate filesystems of a parent +are to be exported, then they must be explicitly exported and the +parent should not have +.I crossmnt +set. + +The +.I nocrossmnt +option can explictly disable +.I crossmnt +if it was previously set. This is rarely useful. .TP .IR no_subtree_check This option disables subtree checking, which has mild security -- cgit