NFSD: Added fault injection

Fault injection on the NFS server makes it easier to test the client's
state manager and recovery threads.  Simulating errors on the server is
easier than finding the right conditions that cause them naturally.

This patch uses debugfs to add a simple framework for fault injection to
the server.  This framework is a config option, and can be enabled
through CONFIG_NFSD_FAULT_INJECTION.  Assuming you have debugfs mounted
to /sys/debug, a set of files will be created in /sys/debug/nfsd/.
Writing to any of these files will cause the corresponding action and
write a log entry to dmesg.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/fs/nfsd/Kconfig b/fs/nfsd/Kconfig
index 10e6366608f2..8df1ea4a6ff9 100644
--- a/fs/nfsd/Kconfig
+++ b/fs/nfsd/Kconfig
@@ -80,3 +80,13 @@ config NFSD_V4
           available from http://linux-nfs.org/.
 
           If unsure, say N.
+
+config NFSD_FAULT_INJECTION
+        bool "NFS server manual fault injection"
+        depends on NFSD_V4 && DEBUG_KERNEL
+        help
+          This option enables support for manually injecting faults
+          into the NFS server.  This is intended to be used for
+          testing error recovery on the NFS client.
+
+          If unsure, say N.