2023-05-11 13:13:38

by Chengen Du

[permalink] [raw]
Subject: [PATCH] nfs(5): adding new mount option 'fasc'

Add an option that triggers the clearing of the file
access cache as soon as the cache timestamp becomes
older than the user's login time.

Signed-off-by: Chengen Du <[email protected]>
---
utils/mount/nfs.man | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/utils/mount/nfs.man b/utils/mount/nfs.man
index 7a410422..68514fbd 100644
--- a/utils/mount/nfs.man
+++ b/utils/mount/nfs.man
@@ -574,6 +574,7 @@ The
.B sloppy
option is an alternative to specifying
.BR mount.nfs " -s " option.
+
.TP 1.5i
.BI xprtsec= policy
Specifies the use of transport layer security to protect NFS network
@@ -607,6 +608,19 @@ option is not specified,
the default behavior depends on the kernel,
but is usually equivalent to
.BR "xprtsec=none" .
+.TP 1.5i
+.B fasc
+Triggers the clearing of the file access cache as soon as the cache
+timestamp becomes older than the user's login time. It is supported
+in kernels 6.4 and later.
+.IP
+NFS servers often refresh their users' group membership at their
+own cadence, which means the NFS client's file access cache can
+become stale if the user's group membership changes on the server
+after they've logged in on the client. To align with the principles
+of the POSIX design, which only refreshes the user's supplementary
+group information upon login, the mechanism uses the user's login
+time to determine whether the file access cache needs to be refreshed.
.SS "Options for NFS versions 2 and 3 only"
Use these options, along with the options in the above subsection,
for NFS versions 2 and 3 only.
--
2.39.2