NFS: Add basic migration support to state manager thread

Migration recovery and state recovery must be serialized, so handle
both in the state manager thread.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index e59d3b4..94e783f 100644 (file)
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -29,6 +29,7 @@ enum nfs4_client_state {
        NFS4CLNT_SERVER_SCOPE_MISMATCH,
        NFS4CLNT_PURGE_STATE,
        NFS4CLNT_BIND_CONN_TO_SESSION,
+       NFS4CLNT_MOVED,
 };
 
 #define NFS4_RENEW_TIMEOUT             0x01
@@ -421,6 +422,7 @@ extern int nfs4_client_recover_expired_lease(struct nfs_client *clp);
 extern void nfs4_schedule_state_manager(struct nfs_client *);
 extern void nfs4_schedule_path_down_recovery(struct nfs_client *clp);
 extern int nfs4_schedule_stateid_recovery(const struct nfs_server *, struct nfs4_state *);
+extern int nfs4_schedule_migration_recovery(const struct nfs_server *);
 extern void nfs41_handle_sequence_flag_errors(struct nfs_client *clp, u32 flags);
 extern void nfs41_handle_server_scope(struct nfs_client *,
                                      struct nfs41_server_scope **);

diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index a2cba66..0cde95e 100644 (file)
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -197,6 +197,7 @@ struct nfs_client *nfs4_alloc_client(const struct nfs_client_initdata *cl_init)
        clp->cl_state = 1 << NFS4CLNT_LEASE_EXPIRED;
        clp->cl_minorversion = cl_init->minorversion;
        clp->cl_mvops = nfs_v4_minor_ops[cl_init->minorversion];
+       clp->cl_mig_gen = 1;
        return clp;
 
 error:

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index fa2706a..ba0db18 100644 (file)
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -239,8 +239,6 @@ static void nfs4_end_drain_session(struct nfs_client *clp)
        }
 }
 
-#if defined(CONFIG_NFS_V4_1)
-
 static int nfs4_drain_slot_tbl(struct nfs4_slot_table *tbl)
 {
        set_bit(NFS4_SLOT_TBL_DRAINING, &tbl->slot_tbl_state);
@@ -270,6 +268,8 @@ static int nfs4_begin_drain_session(struct nfs_client *clp)
        return nfs4_drain_slot_tbl(&ses->fc_slot_table);
 }
 
+#if defined(CONFIG_NFS_V4_1)
+
 static int nfs41_setup_state_renewal(struct nfs_client *clp)
 {
        int status;
@@ -1197,6 +1197,42 @@ void nfs4_schedule_lease_recovery(struct nfs_client *clp)
 }
 EXPORT_SYMBOL_GPL(nfs4_schedule_lease_recovery);
 
+/**
+ * nfs4_schedule_migration_recovery - trigger migration recovery
+ *
+ * @server: FSID that is migrating
+ *
+ * Returns zero if recovery has started, otherwise a negative NFS4ERR
+ * value is returned.
+ */
+int nfs4_schedule_migration_recovery(const struct nfs_server *server)
+{
+       struct nfs_client *clp = server->nfs_client;
+
+       if (server->fh_expire_type != NFS4_FH_PERSISTENT) {
+               pr_err("NFS: volatile file handles not supported (server %s)\n",
+                               clp->cl_hostname);
+               return -NFS4ERR_IO;
+       }
+
+       if (test_bit(NFS_MIG_FAILED, &server->mig_status))
+               return -NFS4ERR_IO;
+
+       dprintk("%s: scheduling migration recovery for (%llx:%llx) on %s\n",
+                       __func__,
+                       (unsigned long long)server->fsid.major,
+                       (unsigned long long)server->fsid.minor,
+                       clp->cl_hostname);
+
+       set_bit(NFS_MIG_IN_TRANSITION,
+                       &((struct nfs_server *)server)->mig_status);
+       set_bit(NFS4CLNT_MOVED, &clp->cl_state);
+
+       nfs4_schedule_state_manager(clp);
+       return 0;
+}
+EXPORT_SYMBOL_GPL(nfs4_schedule_migration_recovery);
+
 int nfs4_wait_clnt_recover(struct nfs_client *clp)
 {
        int res;
@@ -1826,6 +1862,119 @@ static int nfs4_purge_lease(struct nfs_client *clp)
        return 0;
 }
 
+/*
+ * Try remote migration of one FSID from a source server to a
+ * destination server.  The source server provides a list of
+ * potential destinations.
+ *
+ * Returns zero or a negative NFS4ERR status code.
+ */
+static int nfs4_try_migration(struct nfs_server *server, struct rpc_cred *cred)
+{
+       struct nfs_client *clp = server->nfs_client;
+       struct nfs4_fs_locations *locations = NULL;
+       struct inode *inode;
+       struct page *page;
+       int status, result;
+
+       dprintk("--> %s: FSID %llx:%llx on \"%s\"\n", __func__,
+                       (unsigned long long)server->fsid.major,
+                       (unsigned long long)server->fsid.minor,
+                       clp->cl_hostname);
+
+       result = 0;
+       page = alloc_page(GFP_KERNEL);
+       locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
+       if (page == NULL || locations == NULL) {
+               dprintk("<-- %s: no memory\n", __func__);
+               goto out;
+       }
+
+       inode = server->super->s_root->d_inode;
+       result = nfs4_proc_get_locations(inode, locations, page, cred);
+       if (result) {
+               dprintk("<-- %s: failed to retrieve fs_locations: %d\n",
+                       __func__, result);
+               goto out;
+       }
+
+       result = -NFS4ERR_NXIO;
+       if (!(locations->fattr.valid & NFS_ATTR_FATTR_V4_LOCATIONS)) {
+               dprintk("<-- %s: No fs_locations data, migration skipped\n",
+                       __func__);
+               goto out;
+       }
+
+       nfs4_begin_drain_session(clp);
+
+       status = nfs4_replace_transport(server, locations);
+       if (status != 0) {
+               dprintk("<-- %s: failed to replace transport: %d\n",
+                       __func__, status);
+               goto out;
+       }
+
+       result = 0;
+       dprintk("<-- %s: migration succeeded\n", __func__);
+
+out:
+       if (page != NULL)
+               __free_page(page);
+       kfree(locations);
+       if (result) {
+               pr_err("NFS: migration recovery failed (server %s)\n",
+                               clp->cl_hostname);
+               set_bit(NFS_MIG_FAILED, &server->mig_status);
+       }
+       return result;
+}
+
+/*
+ * Returns zero or a negative NFS4ERR status code.
+ */
+static int nfs4_handle_migration(struct nfs_client *clp)
+{
+       const struct nfs4_state_maintenance_ops *ops =
+                               clp->cl_mvops->state_renewal_ops;
+       struct nfs_server *server;
+       struct rpc_cred *cred;
+
+       dprintk("%s: migration reported on \"%s\"\n", __func__,
+                       clp->cl_hostname);
+
+       spin_lock(&clp->cl_lock);
+       cred = ops->get_state_renewal_cred_locked(clp);
+       spin_unlock(&clp->cl_lock);
+       if (cred == NULL)
+               return -NFS4ERR_NOENT;
+
+       clp->cl_mig_gen++;
+restart:
+       rcu_read_lock();
+       list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
+               int status;
+
+               if (server->mig_gen == clp->cl_mig_gen)
+                       continue;
+               server->mig_gen = clp->cl_mig_gen;
+
+               if (!test_and_clear_bit(NFS_MIG_IN_TRANSITION,
+                                               &server->mig_status))
+                       continue;
+
+               rcu_read_unlock();
+               status = nfs4_try_migration(server, cred);
+               if (status < 0) {
+                       put_rpccred(cred);
+                       return status;
+               }
+               goto restart;
+       }
+       rcu_read_unlock();
+       put_rpccred(cred);
+       return 0;
+}
+
 /**
  * nfs4_discover_server_trunking - Detect server IP address trunking
  *
@@ -2154,7 +2303,13 @@ static void nfs4_state_manager(struct nfs_client *clp)
                        status = nfs4_check_lease(clp);
                        if (status < 0)
                                goto out_error;
-                       continue;
+               }
+
+               if (test_and_clear_bit(NFS4CLNT_MOVED, &clp->cl_state)) {
+                       section = "migration";
+                       status = nfs4_handle_migration(clp);
+                       if (status < 0)
+                               goto out_error;
                }
 
                /* First recover reboot state... */

diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 46b0cb4..186ec49 100644 (file)
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -79,6 +79,7 @@ struct nfs_client {
        char                    cl_ipaddr[48];
        u32                     cl_cb_ident;    /* v4.0 callback identifier */
        const struct nfs4_minor_version_ops *cl_mvops;
+       unsigned long           cl_mig_gen;
 
        /* NFSv4.0 transport blocking */
        struct nfs4_slot_table  *cl_slot_tbl;
@@ -189,6 +190,12 @@ struct nfs_server {
        struct list_head        state_owners_lru;
        struct list_head        layouts;
        struct list_head        delegations;
+
+       unsigned long           mig_gen;
+       unsigned long           mig_status;
+#define NFS_MIG_IN_TRANSITION          (1)
+#define NFS_MIG_FAILED                 (2)
+
        void (*destroy)(struct nfs_server *);
 
        atomic_t active; /* Keep trace of any activity to this server */