nfsd: add a v4_end_grace file to /proc/fs/nfsd
Allow a privileged userland process to end the v4 grace period early.
Writing "Y", "y", or "1" to the file will cause the v4 grace period to
be lifted. The basic idea with this will be to allow the userland
client tracking program to lift the grace period once it knows that no
more clients will be reclaiming state.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 08fb273..8f7ace5 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4113,7 +4113,7 @@
return status;
}
-static void
+void
nfsd4_end_grace(struct nfsd_net *nn)
{
/* do nothing if grace period already ended */
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 4e04210..ca73ca7 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -49,6 +49,7 @@
NFSD_Leasetime,
NFSD_Gracetime,
NFSD_RecoveryDir,
+ NFSD_V4EndGrace,
#endif
};
@@ -68,6 +69,7 @@
static ssize_t write_leasetime(struct file *file, char *buf, size_t size);
static ssize_t write_gracetime(struct file *file, char *buf, size_t size);
static ssize_t write_recoverydir(struct file *file, char *buf, size_t size);
+static ssize_t write_v4_end_grace(struct file *file, char *buf, size_t size);
#endif
static ssize_t (*write_op[])(struct file *, char *, size_t) = {
@@ -84,6 +86,7 @@
[NFSD_Leasetime] = write_leasetime,
[NFSD_Gracetime] = write_gracetime,
[NFSD_RecoveryDir] = write_recoverydir,
+ [NFSD_V4EndGrace] = write_v4_end_grace,
#endif
};
@@ -1077,6 +1080,47 @@
return rv;
}
+/**
+ * write_v4_end_grace - release grace period for nfsd's v4.x lock manager
+ *
+ * Input:
+ * buf: ignored
+ * size: zero
+ * OR
+ *
+ * Input:
+ * buf: any value
+ * size: non-zero length of C string in @buf
+ * Output:
+ * passed-in buffer filled with "Y" or "N" with a newline
+ * and NULL-terminated C string. This indicates whether
+ * the grace period has ended in the current net
+ * namespace. Return code is the size in bytes of the
+ * string. Writing a string that starts with 'Y', 'y', or
+ * '1' to the file will end the grace period for nfsd's v4
+ * lock manager.
+ */
+static ssize_t write_v4_end_grace(struct file *file, char *buf, size_t size)
+{
+ struct net *net = file->f_dentry->d_sb->s_fs_info;
+ struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+ if (size > 0) {
+ switch(buf[0]) {
+ case 'Y':
+ case 'y':
+ case '1':
+ nfsd4_end_grace(nn);
+ break;
+ default:
+ return -EINVAL;
+ }
+ }
+
+ return scnprintf(buf, SIMPLE_TRANSACTION_LIMIT, "%c\n",
+ nn->grace_ended ? 'Y' : 'N');
+}
+
#endif
/*----------------------------------------------------------------------------*/
@@ -1110,6 +1154,7 @@
[NFSD_Leasetime] = {"nfsv4leasetime", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Gracetime] = {"nfsv4gracetime", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_RecoveryDir] = {"nfsv4recoverydir", &transaction_ops, S_IWUSR|S_IRUSR},
+ [NFSD_V4EndGrace] = {"v4_end_grace", &transaction_ops, S_IWUSR|S_IRUGO},
#endif
/* last one */ {""}
};
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index a5fa690..854f0c5 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -545,6 +545,9 @@
struct nfsd_net *nn);
extern bool nfs4_has_reclaimed_state(const char *name, struct nfsd_net *nn);
+/* grace period management */
+void nfsd4_end_grace(struct nfsd_net *nn);
+
/* nfs4recover operations */
extern int nfsd4_client_tracking_init(struct net *net);
extern void nfsd4_client_tracking_exit(struct net *net);