pnfs: CB_NOTIFY_DEVICEID

Note: This functionlaity is incomplete as all layout segments referring to
the 'to be removed device id' need to be reaped, and all in flight I/O drained.

[use be32 res in nfs4_callback_devicenotify]
[use nfs_client to qualify deviceid for cb_notify_deviceid]
[use global deviceid cache for CB_NOTIFY_DEVICEID]
[refactor device cache _lookup_deviceid]
[refactor device cache _find_get_deviceid]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[Bug in new global-device-cache code]
[layout_driver MUST set free_deviceid_node if using dev-cache]
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>

5 files changed, 241 insertions, 15 deletions

diff --git a/fs/nfs/callback.h b/fs/nfs/callback.h
index 46d93ce7311b..b257383bb565 100644
--- a/fs/nfs/callback.h
+++ b/fs/nfs/callback.h
@@ -167,6 +167,23 @@ extern unsigned nfs4_callback_layoutrecall(
 
 extern void nfs4_check_drain_bc_complete(struct nfs4_session *ses);
 extern void nfs4_cb_take_slot(struct nfs_client *clp);
+
+struct cb_devicenotifyitem {
+        uint32_t                cbd_notify_type;
+        uint32_t                cbd_layout_type;
+        struct nfs4_deviceid    cbd_dev_id;
+        uint32_t                cbd_immediate;
+};
+
+struct cb_devicenotifyargs {
+        int                              ndevs;
+        struct cb_devicenotifyitem       *devs;
+};
+
+extern __be32 nfs4_callback_devicenotify(
+        struct cb_devicenotifyargs *args,
+        void *dummy, struct cb_process_state *cps);
+
 #endif /* CONFIG_NFS_V4_1 */
 extern int check_gss_callback_principal(struct nfs_client *, struct svc_rqst *);
 extern __be32 nfs4_callback_getattr(struct cb_getattrargs *args,
diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 2f41dccea18e..fb5e5b9a97ae 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -241,6 +241,53 @@ static void pnfs_recall_all_layouts(struct nfs_client *clp)
         do_callback_layoutrecall(clp, &args);
 }
 
+__be32 nfs4_callback_devicenotify(struct cb_devicenotifyargs *args,
+                                  void *dummy, struct cb_process_state *cps)
+{
+        int i;
+        __be32 res = 0;
+        struct nfs_client *clp = cps->clp;
+        struct nfs_server *server = NULL;
+
+        dprintk("%s: -->\n", __func__);
+
+        if (!clp) {
+                res = cpu_to_be32(NFS4ERR_OP_NOT_IN_SESSION);
+                goto out;
+        }
+
+        for (i = 0; i < args->ndevs; i++) {
+                struct cb_devicenotifyitem *dev = &args->devs[i];
+
+                if (!server ||
+                    server->pnfs_curr_ld->id != dev->cbd_layout_type) {
+                        rcu_read_lock();
+                        list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
+                                if (server->pnfs_curr_ld &&
+                                    server->pnfs_curr_ld->id == dev->cbd_layout_type) {
+                                        rcu_read_unlock();
+                                        goto found;
+                                }
+                        rcu_read_unlock();
+                        dprintk("%s: layout type %u not found\n",
+                                __func__, dev->cbd_layout_type);
+                        continue;
+                }
+
+        found:
+                if (dev->cbd_notify_type == NOTIFY_DEVICEID4_CHANGE)
+                        dprintk("%s: NOTIFY_DEVICEID4_CHANGE not supported, "
+                                "deleting instead\n", __func__);
+                nfs4_delete_deviceid(clp, &dev->cbd_dev_id);
+        }
+
+out:
+        kfree(args->devs);
+        dprintk("%s: exit with status = %u\n",
+                __func__, be32_to_cpu(res));
+        return res;
+}
+
 int nfs41_validate_delegation_stateid(struct nfs_delegation *delegation, const nfs4_stateid *stateid)
 {
         if (delegation == NULL)
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index 00ecf62ce7c1..c6c86a77e043 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -25,6 +25,7 @@
 
 #if defined(CONFIG_NFS_V4_1)
 #define CB_OP_LAYOUTRECALL_RES_MAXSZ    (CB_OP_HDR_RES_MAXSZ)
+#define CB_OP_DEVICENOTIFY_RES_MAXSZ    (CB_OP_HDR_RES_MAXSZ)
 #define CB_OP_SEQUENCE_RES_MAXSZ        (CB_OP_HDR_RES_MAXSZ + \
                                         4 + 1 + 3)
 #define CB_OP_RECALLANY_RES_MAXSZ       (CB_OP_HDR_RES_MAXSZ)
@@ -284,6 +285,93 @@ out:
         return status;
 }
 
+static
+__be32 decode_devicenotify_args(struct svc_rqst *rqstp,
+                                struct xdr_stream *xdr,
+                                struct cb_devicenotifyargs *args)
+{
+        __be32 *p;
+        __be32 status = 0;
+        u32 tmp;
+        int n, i;
+        args->ndevs = 0;
+
+        /* Num of device notifications */
+        p = read_buf(xdr, sizeof(uint32_t));
+        if (unlikely(p == NULL)) {
+                status = htonl(NFS4ERR_BADXDR);
+                goto out;
+        }
+        n = ntohl(*p++);
+        if (n <= 0)
+                goto out;
+
+        args->devs = kmalloc(n * sizeof(*args->devs), GFP_KERNEL);
+        if (!args->devs) {
+                status = htonl(NFS4ERR_DELAY);
+                goto out;
+        }
+
+        /* Decode each dev notification */
+        for (i = 0; i < n; i++) {
+                struct cb_devicenotifyitem *dev = &args->devs[i];
+
+                p = read_buf(xdr, (4 * sizeof(uint32_t)) + NFS4_DEVICEID4_SIZE);
+                if (unlikely(p == NULL)) {
+                        status = htonl(NFS4ERR_BADXDR);
+                        goto err;
+                }
+
+                tmp = ntohl(*p++);      /* bitmap size */
+                if (tmp != 1) {
+                        status = htonl(NFS4ERR_INVAL);
+                        goto err;
+                }
+                dev->cbd_notify_type = ntohl(*p++);
+                if (dev->cbd_notify_type != NOTIFY_DEVICEID4_CHANGE &&
+                    dev->cbd_notify_type != NOTIFY_DEVICEID4_DELETE) {
+                        status = htonl(NFS4ERR_INVAL);
+                        goto err;
+                }
+
+                tmp = ntohl(*p++);      /* opaque size */
+                if (((dev->cbd_notify_type == NOTIFY_DEVICEID4_CHANGE) &&
+                     (tmp != NFS4_DEVICEID4_SIZE + 8)) ||
+                    ((dev->cbd_notify_type == NOTIFY_DEVICEID4_DELETE) &&
+                     (tmp != NFS4_DEVICEID4_SIZE + 4))) {
+                        status = htonl(NFS4ERR_INVAL);
+                        goto err;
+                }
+                dev->cbd_layout_type = ntohl(*p++);
+                memcpy(dev->cbd_dev_id.data, p, NFS4_DEVICEID4_SIZE);
+                p += XDR_QUADLEN(NFS4_DEVICEID4_SIZE);
+
+                if (dev->cbd_layout_type == NOTIFY_DEVICEID4_CHANGE) {
+                        p = read_buf(xdr, sizeof(uint32_t));
+                        if (unlikely(p == NULL)) {
+                                status = htonl(NFS4ERR_BADXDR);
+                                goto err;
+                        }
+                        dev->cbd_immediate = ntohl(*p++);
+                } else {
+                        dev->cbd_immediate = 0;
+                }
+
+                args->ndevs++;
+
+                dprintk("%s: type %d layout 0x%x immediate %d\n",
+                        __func__, dev->cbd_notify_type, dev->cbd_layout_type,
+                        dev->cbd_immediate);
+        }
+out:
+        dprintk("%s: status %d ndevs %d\n",
+                __func__, ntohl(status), args->ndevs);
+        return status;
+err:
+        kfree(args->devs);
+        goto out;
+}
+
 static __be32 decode_sessionid(struct xdr_stream *xdr,
                                  struct nfs4_sessionid *sid)
 {
@@ -639,10 +727,10 @@ preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
         case OP_CB_RECALL_ANY:
         case OP_CB_RECALL_SLOT:
         case OP_CB_LAYOUTRECALL:
+        case OP_CB_NOTIFY_DEVICEID:
                 *op = &callback_ops[op_nr];
                 break;
 
-        case OP_CB_NOTIFY_DEVICEID:
         case OP_CB_NOTIFY:
         case OP_CB_PUSH_DELEG:
         case OP_CB_RECALLABLE_OBJ_AVAIL:
@@ -849,6 +937,12 @@ static struct callback_op callback_ops[] = {
                         (callback_decode_arg_t)decode_layoutrecall_args,
                 .res_maxsize = CB_OP_LAYOUTRECALL_RES_MAXSZ,
         },
+        [OP_CB_NOTIFY_DEVICEID] = {
+                .process_op = (callback_process_op_t)nfs4_callback_devicenotify,
+                .decode_args =
+                        (callback_decode_arg_t)decode_devicenotify_args,
+                .res_maxsize = CB_OP_DEVICENOTIFY_RES_MAXSZ,
+        },
         [OP_CB_SEQUENCE] = {
                 .process_op = (callback_process_op_t)nfs4_callback_sequence,
                 .decode_args = (callback_decode_arg_t)decode_cb_sequence_args,
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index 80a5d0e2cc43..fbd3f7cd9e71 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -173,6 +173,7 @@ struct nfs4_deviceid_node {
 void nfs4_print_deviceid(const struct nfs4_deviceid *dev_id);
 struct nfs4_deviceid_node *nfs4_find_get_deviceid(const struct nfs_client *, const struct nfs4_deviceid *);
 struct nfs4_deviceid_node *nfs4_unhash_put_deviceid(const struct nfs_client *, const struct nfs4_deviceid *);
+void nfs4_delete_deviceid(const struct nfs_client *, const struct nfs4_deviceid *);
 void nfs4_init_deviceid_node(struct nfs4_deviceid_node *,
                              const struct pnfs_layoutdriver_type *,
                              const struct nfs_client *,
diff --git a/fs/nfs/pnfs_dev.c b/fs/nfs/pnfs_dev.c
index 64a4b85c7dbc..8fd3839df299 100644
--- a/fs/nfs/pnfs_dev.c
+++ b/fs/nfs/pnfs_dev.c
@@ -66,6 +66,23 @@ nfs4_deviceid_hash(const struct nfs4_deviceid *id)
         return x & NFS4_DEVICE_ID_HASH_MASK;
 }
 
+static struct nfs4_deviceid_node *
+_lookup_deviceid(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->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
  *
@@ -73,26 +90,76 @@ nfs4_deviceid_hash(const struct nfs4_deviceid *id)
  * @id deviceid to look up
  */
 struct nfs4_deviceid_node *
+_find_get_deviceid(const struct nfs_client *clp, const struct nfs4_deviceid *id,
+                   long hash)
+{
+        struct nfs4_deviceid_node *d;
+
+        rcu_read_lock();
+        d = _lookup_deviceid(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 nfs_client *clp, const struct nfs4_deviceid *id)
 {
+        return _find_get_deviceid(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 nfs_client *clp, const struct nfs4_deviceid *id)
+{
         struct nfs4_deviceid_node *d;
-        struct hlist_node *n;
-        long hash = nfs4_deviceid_hash(id);
 
+        spin_lock(&nfs4_deviceid_lock);
         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:
+        d = _lookup_deviceid(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_find_get_deviceid);
+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 nfs_client *clp, const struct nfs4_deviceid *id)
+{
+        struct nfs4_deviceid_node *d;
+
+        d = nfs4_unhash_put_deviceid(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,
@@ -126,13 +193,13 @@ nfs4_insert_deviceid_node(struct nfs4_deviceid_node *new)
         long hash;
 
         spin_lock(&nfs4_deviceid_lock);
-        d = nfs4_find_get_deviceid(new->nfs_client, &new->deviceid);
+        hash = nfs4_deviceid_hash(&new->deviceid);
+        d = _find_get_deviceid(new->nfs_client, &new->deviceid, hash);
         if (d) {
                 spin_unlock(&nfs4_deviceid_lock);
                 return d;
         }
 
-        hash = nfs4_deviceid_hash(&new->deviceid);
         hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
         spin_unlock(&nfs4_deviceid_lock);