From 286eaa95c5c5915a6b72cc3f0a2534161fd7928b Mon Sep 17 00:00:00 2001 From: Joel Becker Date: Fri, 1 Feb 2008 15:03:57 -0800 Subject: ocfs2: Break out stackglue into modules. We define the ocfs2_stack_plugin structure to represent a stack driver. The o2cb stack code is split into stack_o2cb.c. This becomes the ocfs2_stack_o2cb.ko module. The stackglue generic functions are similarly split into the ocfs2_stackglue.ko module. This module now provides an interface to register drivers. The ocfs2_stack_o2cb driver registers itself. As part of this interface, ocfs2_stackglue can load drivers on demand. This is accomplished in ocfs2_cluster_connect(). ocfs2_cluster_disconnect() is now notified when a _hangup() is pending. If a hangup is pending, it will not release the driver module and will let _hangup() do that. Signed-off-by: Joel Becker --- fs/ocfs2/stackglue.c | 238 +++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 214 insertions(+), 24 deletions(-) (limited to 'fs/ocfs2/stackglue.c') diff --git a/fs/ocfs2/stackglue.c b/fs/ocfs2/stackglue.c index e197367b6bd6..1978c9cff0e9 100644 --- a/fs/ocfs2/stackglue.c +++ b/fs/ocfs2/stackglue.c @@ -18,17 +18,176 @@ * General Public License for more details. */ +#include +#include +#include #include #include -/* Needed for AOP_TRUNCATED_PAGE in mlog_errno() */ -#include +#include "stackglue.h" -#include "cluster/masklog.h" +static struct ocfs2_locking_protocol *lproto; +static DEFINE_SPINLOCK(ocfs2_stack_lock); +static LIST_HEAD(ocfs2_stack_list); -#include "stackglue.h" +/* + * The stack currently in use. If not null, active_stack->sp_count > 0, + * the module is pinned, and the locking protocol cannot be changed. + */ +static struct ocfs2_stack_plugin *active_stack; + +static struct ocfs2_stack_plugin *ocfs2_stack_lookup(const char *name) +{ + struct ocfs2_stack_plugin *p; + + assert_spin_locked(&ocfs2_stack_lock); + + list_for_each_entry(p, &ocfs2_stack_list, sp_list) { + if (!strcmp(p->sp_name, name)) + return p; + } + + return NULL; +} + +static int ocfs2_stack_driver_request(const char *name) +{ + int rc; + struct ocfs2_stack_plugin *p; + + spin_lock(&ocfs2_stack_lock); + + if (active_stack) { + /* + * If the active stack isn't the one we want, it cannot + * be selected right now. + */ + if (!strcmp(active_stack->sp_name, name)) + rc = 0; + else + rc = -EBUSY; + goto out; + } + + p = ocfs2_stack_lookup(name); + if (!p || !try_module_get(p->sp_owner)) { + rc = -ENOENT; + goto out; + } + + /* Ok, the stack is pinned */ + p->sp_count++; + active_stack = p; + + rc = 0; + +out: + spin_unlock(&ocfs2_stack_lock); + return rc; +} + +/* + * This function looks up the appropriate stack and makes it active. If + * there is no stack, it tries to load it. It will fail if the stack still + * cannot be found. It will also fail if a different stack is in use. + */ +static int ocfs2_stack_driver_get(const char *name) +{ + int rc; + + rc = ocfs2_stack_driver_request(name); + if (rc == -ENOENT) { + request_module("ocfs2_stack_%s", name); + rc = ocfs2_stack_driver_request(name); + } + + if (rc == -ENOENT) { + printk(KERN_ERR + "ocfs2: Cluster stack driver \"%s\" cannot be found\n", + name); + } else if (rc == -EBUSY) { + printk(KERN_ERR + "ocfs2: A different cluster stack driver is in use\n"); + } + + return rc; +} -struct ocfs2_locking_protocol *stack_glue_lproto; +static void ocfs2_stack_driver_put(void) +{ + spin_lock(&ocfs2_stack_lock); + BUG_ON(active_stack == NULL); + BUG_ON(active_stack->sp_count == 0); + + active_stack->sp_count--; + if (!active_stack->sp_count) { + module_put(active_stack->sp_owner); + active_stack = NULL; + } + spin_unlock(&ocfs2_stack_lock); +} + +int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin) +{ + int rc; + + spin_lock(&ocfs2_stack_lock); + if (!ocfs2_stack_lookup(plugin->sp_name)) { + plugin->sp_count = 0; + plugin->sp_proto = lproto; + list_add(&plugin->sp_list, &ocfs2_stack_list); + printk(KERN_INFO "ocfs2: Registered cluster interface %s\n", + plugin->sp_name); + rc = 0; + } else { + printk(KERN_ERR "ocfs2: Stack \"%s\" already registered\n", + plugin->sp_name); + rc = -EEXIST; + } + spin_unlock(&ocfs2_stack_lock); + + return rc; +} +EXPORT_SYMBOL_GPL(ocfs2_stack_glue_register); + +void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin) +{ + struct ocfs2_stack_plugin *p; + + spin_lock(&ocfs2_stack_lock); + p = ocfs2_stack_lookup(plugin->sp_name); + if (p) { + BUG_ON(p != plugin); + BUG_ON(plugin == active_stack); + BUG_ON(plugin->sp_count != 0); + list_del_init(&plugin->sp_list); + printk(KERN_INFO "ocfs2: Unregistered cluster interface %s\n", + plugin->sp_name); + } else { + printk(KERN_ERR "Stack \"%s\" is not registered\n", + plugin->sp_name); + } + spin_unlock(&ocfs2_stack_lock); +} +EXPORT_SYMBOL_GPL(ocfs2_stack_glue_unregister); + +void ocfs2_stack_glue_set_locking_protocol(struct ocfs2_locking_protocol *proto) +{ + struct ocfs2_stack_plugin *p; + + BUG_ON(proto == NULL); + + spin_lock(&ocfs2_stack_lock); + BUG_ON(active_stack != NULL); + + lproto = proto; + list_for_each_entry(p, &ocfs2_stack_list, sp_list) { + p->sp_proto = lproto; + } + + spin_unlock(&ocfs2_stack_lock); +} +EXPORT_SYMBOL_GPL(ocfs2_stack_glue_set_locking_protocol); int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn, @@ -39,26 +198,29 @@ int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn, unsigned int namelen, void *astarg) { - BUG_ON(stack_glue_lproto == NULL); + BUG_ON(lproto == NULL); - return o2cb_stack_ops.dlm_lock(conn, mode, lksb, flags, - name, namelen, astarg); + return active_stack->sp_ops->dlm_lock(conn, mode, lksb, flags, + name, namelen, astarg); } +EXPORT_SYMBOL_GPL(ocfs2_dlm_lock); int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn, union ocfs2_dlm_lksb *lksb, u32 flags, void *astarg) { - BUG_ON(stack_glue_lproto == NULL); + BUG_ON(lproto == NULL); - return o2cb_stack_ops.dlm_unlock(conn, lksb, flags, astarg); + return active_stack->sp_ops->dlm_unlock(conn, lksb, flags, astarg); } +EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock); int ocfs2_dlm_lock_status(union ocfs2_dlm_lksb *lksb) { - return o2cb_stack_ops.lock_status(lksb); + return active_stack->sp_ops->lock_status(lksb); } +EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status); /* * Why don't we cast to ocfs2_meta_lvb? The "clean" answer is that we @@ -67,13 +229,15 @@ int ocfs2_dlm_lock_status(union ocfs2_dlm_lksb *lksb) */ void *ocfs2_dlm_lvb(union ocfs2_dlm_lksb *lksb) { - return o2cb_stack_ops.lock_lvb(lksb); + return active_stack->sp_ops->lock_lvb(lksb); } +EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb); void ocfs2_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb) { - o2cb_stack_ops.dump_lksb(lksb); + active_stack->sp_ops->dump_lksb(lksb); } +EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb); int ocfs2_cluster_connect(const char *group, int grouplen, @@ -107,11 +271,16 @@ int ocfs2_cluster_connect(const char *group, new_conn->cc_recovery_data = recovery_data; /* Start the new connection at our maximum compatibility level */ - new_conn->cc_version = stack_glue_lproto->lp_max_version; + new_conn->cc_version = lproto->lp_max_version; + + /* This will pin the stack driver if successful */ + rc = ocfs2_stack_driver_get("o2cb"); + if (rc) + goto out_free; - rc = o2cb_stack_ops.connect(new_conn); + rc = active_stack->sp_ops->connect(new_conn); if (rc) { - mlog_errno(rc); + ocfs2_stack_driver_put(); goto out_free; } @@ -124,39 +293,60 @@ out_free: out: return rc; } +EXPORT_SYMBOL_GPL(ocfs2_cluster_connect); -int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn) +/* If hangup_pending is 0, the stack driver will be dropped */ +int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn, + int hangup_pending) { int ret; BUG_ON(conn == NULL); - ret = o2cb_stack_ops.disconnect(conn); + ret = active_stack->sp_ops->disconnect(conn, hangup_pending); /* XXX Should we free it anyway? */ - if (!ret) + if (!ret) { kfree(conn); + if (!hangup_pending) + ocfs2_stack_driver_put(); + } return ret; } +EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect); void ocfs2_cluster_hangup(const char *group, int grouplen) { BUG_ON(group == NULL); BUG_ON(group[grouplen] != '\0'); - o2cb_stack_ops.hangup(group, grouplen); + active_stack->sp_ops->hangup(group, grouplen); + + /* cluster_disconnect() was called with hangup_pending==1 */ + ocfs2_stack_driver_put(); } +EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup); int ocfs2_cluster_this_node(unsigned int *node) { - return o2cb_stack_ops.this_node(node); + return active_stack->sp_ops->this_node(node); } +EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node); -void ocfs2_stack_glue_set_locking_protocol(struct ocfs2_locking_protocol *proto) + +static int __init ocfs2_stack_glue_init(void) { - BUG_ON(proto != NULL); + return 0; +} - stack_glue_lproto = proto; +static void __exit ocfs2_stack_glue_exit(void) +{ + lproto = NULL; } +MODULE_AUTHOR("Oracle"); +MODULE_DESCRIPTION("ocfs2 cluter stack glue layer"); +MODULE_LICENSE("GPL"); +module_init(ocfs2_stack_glue_init); +module_exit(ocfs2_stack_glue_exit); -- cgit v1.2.3-59-g8ed1b