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From:   Richard Weinberger <richard@nod.at>
To:     linux-nfs@vger.kernel.org
Cc:     david@sigma-star.at, david.oberhollenzer@sigma-star.at,
        luis.turcitu@appsbroker.com, david.young@appsbroker.com,
        trond.myklebust@hammerspace.com, anna.schumaker@netapp.com,
        steved@redhat.com, chris.chilvers@appsbroker.com,
        Richard Weinberger <richard@nod.at>
Subject: [PATCH 5/8] exports.man: Document reexport= option
Date:   Tue, 18 Apr 2023 11:33:47 +0200
Message-Id: <20230418093350.4550-6-richard@nod.at>
In-Reply-To: <20230418093350.4550-1-richard@nod.at>
References: <20230418093350.4550-1-richard@nod.at>
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Signed-off-by: Richard Weinberger <richard@nod.at>
---
 utils/exportfs/exports.man | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/utils/exportfs/exports.man b/utils/exportfs/exports.man
index 83dd6807..b7582776 100644
--- a/utils/exportfs/exports.man
+++ b/utils/exportfs/exports.man
@@ -468,6 +468,37 @@ will only work if all clients use a consistent secur=
ity policy.  Note
 that early kernels did not support this export option, and instead
 enabled security labels by default.
=20
+.TP
+.IR reexport=3D auto-fsidnum|predefined-fsidnum
+This option helps when a NFS share is re-exported. Since the NFS server
+needs a unique identifier for each exported filesystem and a NFS share
+cannot provide such, usually a manual fsid is needed.
+As soon
+.IR crossmnt
+is used manually assigning fsid won't work anymore. This is where this
+option becomes handy. It will automatically assign a numerical fsid
+to exported NFS shares. The fsid and path relations are stored in a SQLi=
te
+database. If
+.IR auto-fsidnum
+is selected, the fsid is also autmatically allocated.
+.IR predefined-fsidnum
+assumes pre-allocated fsid numbers and will just look them up.
+This option depends also on the kernel, you will need at least kernel ve=
rsion
+5.19.
+Since
+.IR reexport=3D
+can automatically allocate and assign numerical fsids, it is no longer p=
ossible
+to have numerical fsids in other exports as soon this option is used in =
at least
+one export entry.
+
+The association between fsid numbers and paths is stored in a SQLite dat=
abase.
+Don't edit or remove the database unless you know exactly what you're do=
ing.
+.IR predefined-fsidnum
+is useful when you have used
+.IR auto-fsidnum
+before and don't want further entries stored.
+
+
 .SS User ID Mapping
 .PP
 .B nfsd
--=20
2.31.1