From: Evan McNabb <emcnabb@redhat.com>
Date: Fri, 15 May 2009 13:19:52 -0400
Subject: [nfs] make nfsv4recoverydir proc file readable
Message-id: 4A0DA438.8040809@redhat.com
O-Subject: [RHEL5.4 patch] BZ 499840: nfs: make nfsv4recoverydir proc file readable
Bugzilla: 499840
RH-Acked-by: Jeff Layton <jlayton@redhat.com>

BZ 499840

The file /proc/fs/nfsd/nfsv4recoverydir is not readable on RHEL5.
Instead of returning the value of recoverydir it returns -EINVAL:

# cat /proc/fs/nfsd/nfsv4recoverydir
cat: /proc/fs/nfsd/nfsv4recoverydir: Invalid argument

The attached patch is a backport of the required portions of the
upstream commit:

commit 3dd98a3bccb1bdd30b8a4a755e7bead1b64160ec
Author: Jeff Layton <jlayton@redhat.com>
Date:   Tue Jun 10 08:40:36 2008 -0400
    knfsd: clean up nfsd filesystem interfaces

I've tested on several systems and it seems to work as expected.

-Evan

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index a6489a4..b5c6449 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3311,6 +3311,12 @@ nfs4_reset_recoverydir(char *recdir)
 	return status;
 }
 
+char *
+nfs4_recoverydir(void)
+{
+	return user_recovery_dirname;
+}
+
 /*
  * Called when leasetime is changed.
  *
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index c343957..e76b8e7 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -511,22 +511,29 @@ static ssize_t write_leasetime(struct file *file, char *buf, size_t size)
 	return strlen(buf);
 }
 
+extern char *nfs4_recoverydir(void);
+
 static ssize_t write_recoverydir(struct file *file, char *buf, size_t size)
 {
 	char *mesg = buf;
 	char *recdir;
 	int len, status;
 
-	if (size > PATH_MAX || buf[size-1] != '\n')
-		return -EINVAL;
-	buf[size-1] = 0;
+	if (size > 0) {
+		if (nfsd_serv)
+			return -EBUSY;
+		if (size > PATH_MAX || buf[size-1] != '\n')
+			return -EINVAL;
+		buf[size-1] = 0;
 
-	recdir = mesg;
-	len = qword_get(&mesg, recdir, size);
-	if (len <= 0)
-		return -EINVAL;
+		recdir = mesg;
+		len = qword_get(&mesg, recdir, size);
+		if (len <= 0)
+			return -EINVAL;
 
-	status = nfs4_reset_recoverydir(recdir);
+		status = nfs4_reset_recoverydir(recdir);
+	}
+	sprintf(buf, "%s\n", nfs4_recoverydir());
 	return strlen(buf);
 }
 #endif