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authorBenny Halevy <bhalevy@panasas.com>2011-05-19 22:14:47 -0400
committerBoaz Harrosh <bharrosh@panasas.com>2011-05-29 12:09:48 +0300
commita1eaecbc4c8307e27772d6584ef85a2e93250661 (patch)
tree940549d45db98a5bcfe22501de0bbe9c96de4c8e /fs/nfs/pnfs_dev.c
parent45df3c8b0f3a58facb125d7631890426706c0bfa (diff)
downloadlinux-a1eaecbc4c8307e27772d6584ef85a2e93250661.tar.bz2
NFSv4.1: make deviceid cache global
Move deviceid cache from the pnfs files layout driver to the generic layer in preparation for the objects layout driver. Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Diffstat (limited to 'fs/nfs/pnfs_dev.c')
-rw-r--r--fs/nfs/pnfs_dev.c156
1 files changed, 156 insertions, 0 deletions
diff --git a/fs/nfs/pnfs_dev.c b/fs/nfs/pnfs_dev.c
new file mode 100644
index 000000000000..bf05189a7cbf
--- /dev/null
+++ b/fs/nfs/pnfs_dev.c
@@ -0,0 +1,156 @@
+/*
+ * Device operations for the pnfs client.
+ *
+ * Copyright (c) 2002
+ * The Regents of the University of Michigan
+ * All Rights Reserved
+ *
+ * Dean Hildebrand <dhildebz@umich.edu>
+ * Garth Goodson <Garth.Goodson@netapp.com>
+ *
+ * Permission is granted to use, copy, create derivative works, and
+ * redistribute this software and such derivative works for any purpose,
+ * so long as the name of the University of Michigan is not used in
+ * any advertising or publicity pertaining to the use or distribution
+ * of this software without specific, written prior authorization. If
+ * the above copyright notice or any other identification of the
+ * University of Michigan is included in any copy of any portion of
+ * this software, then the disclaimer below must also be included.
+ *
+ * This software is provided as is, without representation or warranty
+ * of any kind either express or implied, including without limitation
+ * the implied warranties of merchantability, fitness for a particular
+ * purpose, or noninfringement. The Regents of the University of
+ * Michigan shall not be liable for any damages, including special,
+ * indirect, incidental, or consequential damages, with respect to any
+ * claim arising out of or in connection with the use of the software,
+ * even if it has been or is hereafter advised of the possibility of
+ * such damages.
+ */
+
+#include "pnfs.h"
+
+#define NFSDBG_FACILITY NFSDBG_PNFS
+
+/*
+ * Device ID RCU cache. A device ID is unique per server and layout type.
+ */
+#define NFS4_DEVICE_ID_HASH_BITS 5
+#define NFS4_DEVICE_ID_HASH_SIZE (1 << NFS4_DEVICE_ID_HASH_BITS)
+#define NFS4_DEVICE_ID_HASH_MASK (NFS4_DEVICE_ID_HASH_SIZE - 1)
+
+static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE];
+static DEFINE_SPINLOCK(nfs4_deviceid_lock);
+
+void
+nfs4_print_deviceid(const struct nfs4_deviceid *id)
+{
+ u32 *p = (u32 *)id;
+
+ dprintk("%s: device id= [%x%x%x%x]\n", __func__,
+ p[0], p[1], p[2], p[3]);
+}
+EXPORT_SYMBOL_GPL(nfs4_print_deviceid);
+
+static inline u32
+nfs4_deviceid_hash(const struct nfs4_deviceid *id)
+{
+ unsigned char *cptr = (unsigned char *)id->data;
+ unsigned int nbytes = NFS4_DEVICEID4_SIZE;
+ u32 x = 0;
+
+ while (nbytes--) {
+ x *= 37;
+ x += *cptr++;
+ }
+ return x & NFS4_DEVICE_ID_HASH_MASK;
+}
+
+/*
+ * Lookup a deviceid in cache and get a reference count on it if found
+ *
+ * @clp nfs_client associated with deviceid
+ * @id deviceid to look up
+ */
+struct nfs4_deviceid_node *
+nfs4_find_get_deviceid(const struct nfs_client *clp, const struct nfs4_deviceid *id)
+{
+ struct nfs4_deviceid_node *d;
+ struct hlist_node *n;
+ long hash = nfs4_deviceid_hash(id);
+
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node) {
+ if (d->nfs_client == clp && !memcmp(&d->deviceid, id, sizeof(*id))) {
+ if (!atomic_inc_not_zero(&d->ref))
+ goto fail;
+ rcu_read_unlock();
+ return d;
+ }
+ }
+fail:
+ rcu_read_unlock();
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
+
+void
+nfs4_init_deviceid_node(struct nfs4_deviceid_node *d,
+ const struct nfs_client *nfs_client,
+ const struct nfs4_deviceid *id)
+{
+ d->nfs_client = nfs_client;
+ d->deviceid = *id;
+}
+EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node);
+
+/*
+ * Uniquely initialize and insert a deviceid node into cache
+ *
+ * @new new deviceid node
+ * Note that the caller must set up new->nfs_client and new->deviceid
+ *
+ * @ret the inserted node, if none found, otherwise, the found entry.
+ */
+struct nfs4_deviceid_node *
+nfs4_insert_deviceid_node(struct nfs4_deviceid_node *new)
+{
+ struct nfs4_deviceid_node *d;
+ long hash;
+
+ spin_lock(&nfs4_deviceid_lock);
+ d = nfs4_find_get_deviceid(new->nfs_client, &new->deviceid);
+ if (d) {
+ spin_unlock(&nfs4_deviceid_lock);
+ return d;
+ }
+
+ INIT_HLIST_NODE(&new->node);
+ atomic_set(&new->ref, 1);
+ hash = nfs4_deviceid_hash(&new->deviceid);
+ hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
+ spin_unlock(&nfs4_deviceid_lock);
+
+ return new;
+}
+EXPORT_SYMBOL_GPL(nfs4_insert_deviceid_node);
+
+/*
+ * Dereference a deviceid node and delete it when its reference count drops
+ * to zero.
+ *
+ * @d deviceid node to put
+ *
+ * @ret true iff the node was deleted
+ */
+bool
+nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
+{
+ if (!atomic_dec_and_lock(&d->ref, &nfs4_deviceid_lock))
+ return false;
+ hlist_del_init_rcu(&d->node);
+ spin_unlock(&nfs4_deviceid_lock);
+ synchronize_rcu();
+ return true;
+}
+EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);