1 files changed, 270 insertions, 0 deletions

diff --git a/fs/nfs/pnfs_dev.c b/fs/nfs/pnfs_dev.c
new file mode 100644
index 000000000000..c65e133ce9c0
--- /dev/null
+++ b/fs/nfs/pnfs_dev.c
@@ -0,0 +1,270 @@
+/*
+ *  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;
+}
+
+static struct nfs4_deviceid_node *
+_lookup_deviceid(const struct pnfs_layoutdriver_type *ld,
+                 const struct nfs_client *clp, const struct nfs4_deviceid *id,
+                 long hash)
+{
+        struct nfs4_deviceid_node *d;
+        struct hlist_node *n;
+
+        hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node)
+                if (d->ld == ld && d->nfs_client == clp &&
+                    !memcmp(&d->deviceid, id, sizeof(*id))) {
+                        if (atomic_read(&d->ref))
+                                return d;
+                        else
+                                continue;
+                }
+        return NULL;
+}
+
+/*
+ * 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 *
+_find_get_deviceid(const struct pnfs_layoutdriver_type *ld,
+                   const struct nfs_client *clp, const struct nfs4_deviceid *id,
+                   long hash)
+{
+        struct nfs4_deviceid_node *d;
+
+        rcu_read_lock();
+        d = _lookup_deviceid(ld, clp, id, hash);
+        if (d && !atomic_inc_not_zero(&d->ref))
+                d = NULL;
+        rcu_read_unlock();
+        return d;
+}
+
+struct nfs4_deviceid_node *
+nfs4_find_get_deviceid(const struct pnfs_layoutdriver_type *ld,
+                       const struct nfs_client *clp, const struct nfs4_deviceid *id)
+{
+        return _find_get_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
+}
+EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
+
+/*
+ * Unhash and put deviceid
+ *
+ * @clp nfs_client associated with deviceid
+ * @id the deviceid to unhash
+ *
+ * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
+ */
+struct nfs4_deviceid_node *
+nfs4_unhash_put_deviceid(const struct pnfs_layoutdriver_type *ld,
+                         const struct nfs_client *clp, const struct nfs4_deviceid *id)
+{
+        struct nfs4_deviceid_node *d;
+
+        spin_lock(&nfs4_deviceid_lock);
+        rcu_read_lock();
+        d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
+        rcu_read_unlock();
+        if (!d) {
+                spin_unlock(&nfs4_deviceid_lock);
+                return NULL;
+        }
+        hlist_del_init_rcu(&d->node);
+        spin_unlock(&nfs4_deviceid_lock);
+        synchronize_rcu();
+
+        /* balance the initial ref set in pnfs_insert_deviceid */
+        if (atomic_dec_and_test(&d->ref))
+                return d;
+
+        return NULL;
+}
+EXPORT_SYMBOL_GPL(nfs4_unhash_put_deviceid);
+
+/*
+ * Delete a deviceid from cache
+ *
+ * @clp struct nfs_client qualifying the deviceid
+ * @id deviceid to delete
+ */
+void
+nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,
+                     const struct nfs_client *clp, const struct nfs4_deviceid *id)
+{
+        struct nfs4_deviceid_node *d;
+
+        d = nfs4_unhash_put_deviceid(ld, clp, id);
+        if (!d)
+                return;
+        d->ld->free_deviceid_node(d);
+}
+EXPORT_SYMBOL_GPL(nfs4_delete_deviceid);
+
+void
+nfs4_init_deviceid_node(struct nfs4_deviceid_node *d,
+                        const struct pnfs_layoutdriver_type *ld,
+                        const struct nfs_client *nfs_client,
+                        const struct nfs4_deviceid *id)
+{
+        INIT_HLIST_NODE(&d->node);
+        d->ld = ld;
+        d->nfs_client = nfs_client;
+        d->deviceid = *id;
+        atomic_set(&d->ref, 1);
+}
+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 the following members:
+ *        new->ld
+ *        new->nfs_client
+ *        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);
+        hash = nfs4_deviceid_hash(&new->deviceid);
+        d = _find_get_deviceid(new->ld, new->nfs_client, &new->deviceid, hash);
+        if (d) {
+                spin_unlock(&nfs4_deviceid_lock);
+                return d;
+        }
+
+        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();
+        d->ld->free_deviceid_node(d);
+        return true;
+}
+EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);
+
+static void
+_deviceid_purge_client(const struct nfs_client *clp, long hash)
+{
+        struct nfs4_deviceid_node *d;
+        struct hlist_node *n, *next;
+        HLIST_HEAD(tmp);
+
+        rcu_read_lock();
+        hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node)
+                if (d->nfs_client == clp && atomic_read(&d->ref)) {
+                        hlist_del_init_rcu(&d->node);
+                        hlist_add_head(&d->node, &tmp);
+                }
+        rcu_read_unlock();
+
+        if (hlist_empty(&tmp))
+                return;
+
+        synchronize_rcu();
+        hlist_for_each_entry_safe(d, n, next, &tmp, node)
+                if (atomic_dec_and_test(&d->ref))
+                        d->ld->free_deviceid_node(d);
+}
+
+void
+nfs4_deviceid_purge_client(const struct nfs_client *clp)
+{
+        long h;
+
+        spin_lock(&nfs4_deviceid_lock);
+        for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
+                _deviceid_purge_client(clp, h);
+        spin_unlock(&nfs4_deviceid_lock);
+}