1 files changed, 407 insertions, 102 deletions

diff --git a/fs/afs/callback.c b/fs/afs/callback.c
index 9cb206e9d4be..639399f0ab6f 100644
--- a/fs/afs/callback.c
+++ b/fs/afs/callback.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2002 Red Hat, Inc. All rights reserved.
+ * Copyright (c) 2002, 2007 Red Hat, Inc. All rights reserved.
  *
  * This software may be freely redistributed under the terms of the
  * GNU General Public License.
@@ -16,85 +16,187 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
-#include "server.h"
-#include "vnode.h"
+#include <linux/circ_buf.h>
 #include "internal.h"
-#include "cmservice.h"
 
-/*****************************************************************************/
+unsigned afs_vnode_update_timeout = 10;
+
+#define afs_breakring_space(server) \
+        CIRC_SPACE((server)->cb_break_head, (server)->cb_break_tail,    \
+                   ARRAY_SIZE((server)->cb_break))
+
+//static void afs_callback_updater(struct work_struct *);
+
+static struct workqueue_struct *afs_callback_update_worker;
+
 /*
  * allow the fileserver to request callback state (re-)initialisation
  */
-int SRXAFSCM_InitCallBackState(struct afs_server *server)
+void afs_init_callback_state(struct afs_server *server)
 {
-        struct list_head callbacks;
+        struct afs_vnode *vnode;
 
-        _enter("%p", server);
+        _enter("{%p}", server);
 
-        INIT_LIST_HEAD(&callbacks);
-
-        /* transfer the callback list from the server to a temp holding area */
         spin_lock(&server->cb_lock);
 
-        list_add(&callbacks, &server->cb_promises);
-        list_del_init(&server->cb_promises);
+        /* kill all the promises on record from this server */
+        while (!RB_EMPTY_ROOT(&server->cb_promises)) {
+                vnode = rb_entry(server->cb_promises.rb_node,
+                                 struct afs_vnode, cb_promise);
+                _debug("UNPROMISE { vid=%x vn=%u uq=%u}",
+                       vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique);
+                rb_erase(&vnode->cb_promise, &server->cb_promises);
+                vnode->cb_promised = false;
+        }
 
-        /* munch our way through the list, grabbing the inode, dropping all the
-         * locks and regetting them in the right order
-         */
-        while (!list_empty(&callbacks)) {
-                struct afs_vnode *vnode;
-                struct inode *inode;
+        spin_unlock(&server->cb_lock);
+        _leave("");
+}
 
-                vnode = list_entry(callbacks.next, struct afs_vnode, cb_link);
-                list_del_init(&vnode->cb_link);
+/*
+ * handle the data invalidation side of a callback being broken
+ */
+void afs_broken_callback_work(struct work_struct *work)
+{
+        struct afs_vnode *vnode =
+                container_of(work, struct afs_vnode, cb_broken_work);
 
-                /* try and grab the inode - may fail */
-                inode = igrab(AFS_VNODE_TO_I(vnode));
-                if (inode) {
-                        int release = 0;
+        _enter("");
 
-                        spin_unlock(&server->cb_lock);
-                        spin_lock(&vnode->lock);
+        if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
+                return;
 
-                        if (vnode->cb_server == server) {
-                                vnode->cb_server = NULL;
-                                afs_kafstimod_del_timer(&vnode->cb_timeout);
-                                spin_lock(&afs_cb_hash_lock);
-                                list_del_init(&vnode->cb_hash_link);
-                                spin_unlock(&afs_cb_hash_lock);
-                                release = 1;
-                        }
+        /* we're only interested in dealing with a broken callback on *this*
+         * vnode and only if no-one else has dealt with it yet */
+        if (!mutex_trylock(&vnode->validate_lock))
+                return; /* someone else is dealing with it */
 
-                        spin_unlock(&vnode->lock);
+        if (test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
+                if (S_ISDIR(vnode->vfs_inode.i_mode))
+                        afs_clear_permits(vnode);
 
-                        iput(inode);
-                        afs_put_server(server);
+                if (afs_vnode_fetch_status(vnode, NULL, NULL) < 0)
+                        goto out;
 
-                        spin_lock(&server->cb_lock);
+                if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
+                        goto out;
+
+                /* if the vnode's data version number changed then its contents
+                 * are different */
+                if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
+                        _debug("zap data {%x:%u}",
+                               vnode->fid.vid, vnode->fid.vnode);
+                        invalidate_remote_inode(&vnode->vfs_inode);
                 }
         }
 
-        spin_unlock(&server->cb_lock);
+out:
+        mutex_unlock(&vnode->validate_lock);
 
-        _leave(" = 0");
-        return 0;
-} /* end SRXAFSCM_InitCallBackState() */
+        /* avoid the potential race whereby the mutex_trylock() in this
+         * function happens again between the clear_bit() and the
+         * mutex_unlock() */
+        if (test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
+                _debug("requeue");
+                queue_work(afs_callback_update_worker, &vnode->cb_broken_work);
+        }
+        _leave("");
+}
+
+/*
+ * actually break a callback
+ */
+static void afs_break_callback(struct afs_server *server,
+                               struct afs_vnode *vnode)
+{
+        _enter("");
+
+        set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
+
+        if (vnode->cb_promised) {
+                spin_lock(&vnode->lock);
+
+                _debug("break callback");
+
+                spin_lock(&server->cb_lock);
+                if (vnode->cb_promised) {
+                        rb_erase(&vnode->cb_promise, &server->cb_promises);
+                        vnode->cb_promised = false;
+                }
+                spin_unlock(&server->cb_lock);
+
+                queue_work(afs_callback_update_worker, &vnode->cb_broken_work);
+                spin_unlock(&vnode->lock);
+        }
+}
+
+/*
+ * allow the fileserver to explicitly break one callback
+ * - happens when
+ *   - the backing file is changed
+ *   - a lock is released
+ */
+static void afs_break_one_callback(struct afs_server *server,
+                                   struct afs_fid *fid)
+{
+        struct afs_vnode *vnode;
+        struct rb_node *p;
+
+        _debug("find");
+        spin_lock(&server->fs_lock);
+        p = server->fs_vnodes.rb_node;
+        while (p) {
+                vnode = rb_entry(p, struct afs_vnode, server_rb);
+                if (fid->vid < vnode->fid.vid)
+                        p = p->rb_left;
+                else if (fid->vid > vnode->fid.vid)
+                        p = p->rb_right;
+                else if (fid->vnode < vnode->fid.vnode)
+                        p = p->rb_left;
+                else if (fid->vnode > vnode->fid.vnode)
+                        p = p->rb_right;
+                else if (fid->unique < vnode->fid.unique)
+                        p = p->rb_left;
+                else if (fid->unique > vnode->fid.unique)
+                        p = p->rb_right;
+                else
+                        goto found;
+        }
+
+        /* not found so we just ignore it (it may have moved to another
+         * server) */
+not_available:
+        _debug("not avail");
+        spin_unlock(&server->fs_lock);
+        _leave("");
+        return;
+
+found:
+        _debug("found");
+        ASSERTCMP(server, ==, vnode->server);
+
+        if (!igrab(AFS_VNODE_TO_I(vnode)))
+                goto not_available;
+        spin_unlock(&server->fs_lock);
+
+        afs_break_callback(server, vnode);
+        iput(&vnode->vfs_inode);
+        _leave("");
+}
 
-/*****************************************************************************/
 /*
  * allow the fileserver to break callback promises
  */
-int SRXAFSCM_CallBack(struct afs_server *server, size_t count,
-                      struct afs_callback callbacks[])
+void afs_break_callbacks(struct afs_server *server, size_t count,
+                         struct afs_callback callbacks[])
 {
-        _enter("%p,%u,", server, count);
+        _enter("%p,%zu,", server, count);
 
-        for (; count > 0; callbacks++, count--) {
-                struct afs_vnode *vnode = NULL;
-                struct inode *inode = NULL;
-                int valid = 0;
+        ASSERT(server != NULL);
+        ASSERTCMP(count, <=, AFSCBMAX);
 
+        for (; count > 0; callbacks++, count--) {
                 _debug("- Fid { vl=%08x n=%u u=%u }  CB { v=%u x=%u t=%u }",
                        callbacks->fid.vid,
                        callbacks->fid.vnode,
@@ -103,67 +205,270 @@ int SRXAFSCM_CallBack(struct afs_server *server, size_t count,
                        callbacks->expiry,
                        callbacks->type
                        );
+                afs_break_one_callback(server, &callbacks->fid);
+        }
 
-                /* find the inode for this fid */
-                spin_lock(&afs_cb_hash_lock);
+        _leave("");
+        return;
+}
 
-                list_for_each_entry(vnode,
-                                    &afs_cb_hash(server, &callbacks->fid),
-                                    cb_hash_link) {
-                        if (memcmp(&vnode->fid, &callbacks->fid,
-                                   sizeof(struct afs_fid)) != 0)
-                                continue;
+/*
+ * record the callback for breaking
+ * - the caller must hold server->cb_lock
+ */
+static void afs_do_give_up_callback(struct afs_server *server,
+                                    struct afs_vnode *vnode)
+{
+        struct afs_callback *cb;
 
-                        /* right vnode, but is it same server? */
-                        if (vnode->cb_server != server)
-                                break; /* no */
+        _enter("%p,%p", server, vnode);
 
-                        /* try and nail the inode down */
-                        inode = igrab(AFS_VNODE_TO_I(vnode));
-                        break;
+        cb = &server->cb_break[server->cb_break_head];
+        cb->fid         = vnode->fid;
+        cb->version     = vnode->cb_version;
+        cb->expiry      = vnode->cb_expiry;
+        cb->type        = vnode->cb_type;
+        smp_wmb();
+        server->cb_break_head =
+                (server->cb_break_head + 1) &
+                (ARRAY_SIZE(server->cb_break) - 1);
+
+        /* defer the breaking of callbacks to try and collect as many as
+         * possible to ship in one operation */
+        switch (atomic_inc_return(&server->cb_break_n)) {
+        case 1 ... AFSCBMAX - 1:
+                queue_delayed_work(afs_callback_update_worker,
+                                   &server->cb_break_work, HZ * 2);
+                break;
+        case AFSCBMAX:
+                afs_flush_callback_breaks(server);
+                break;
+        default:
+                break;
+        }
+
+        ASSERT(server->cb_promises.rb_node != NULL);
+        rb_erase(&vnode->cb_promise, &server->cb_promises);
+        vnode->cb_promised = false;
+        _leave("");
+}
+
+/*
+ * discard the callback on a deleted item
+ */
+void afs_discard_callback_on_delete(struct afs_vnode *vnode)
+{
+        struct afs_server *server = vnode->server;
+
+        _enter("%d", vnode->cb_promised);
+
+        if (!vnode->cb_promised) {
+                _leave(" [not promised]");
+                return;
+        }
+
+        ASSERT(server != NULL);
+
+        spin_lock(&server->cb_lock);
+        if (vnode->cb_promised) {
+                ASSERT(server->cb_promises.rb_node != NULL);
+                rb_erase(&vnode->cb_promise, &server->cb_promises);
+                vnode->cb_promised = false;
+        }
+        spin_unlock(&server->cb_lock);
+        _leave("");
+}
+
+/*
+ * give up the callback registered for a vnode on the file server when the
+ * inode is being cleared
+ */
+void afs_give_up_callback(struct afs_vnode *vnode)
+{
+        struct afs_server *server = vnode->server;
+
+        DECLARE_WAITQUEUE(myself, current);
+
+        _enter("%d", vnode->cb_promised);
+
+        _debug("GIVE UP INODE %p", &vnode->vfs_inode);
+
+        if (!vnode->cb_promised) {
+                _leave(" [not promised]");
+                return;
+        }
+
+        ASSERT(server != NULL);
+
+        spin_lock(&server->cb_lock);
+        if (vnode->cb_promised && afs_breakring_space(server) == 0) {
+                add_wait_queue(&server->cb_break_waitq, &myself);
+                for (;;) {
+                        set_current_state(TASK_UNINTERRUPTIBLE);
+                        if (!vnode->cb_promised ||
+                            afs_breakring_space(server) != 0)
+                                break;
+                        spin_unlock(&server->cb_lock);
+                        schedule();
+                        spin_lock(&server->cb_lock);
                 }
+                remove_wait_queue(&server->cb_break_waitq, &myself);
+                __set_current_state(TASK_RUNNING);
+        }
+
+        /* of course, it's always possible for the server to break this vnode's
+         * callback first... */
+        if (vnode->cb_promised)
+                afs_do_give_up_callback(server, vnode);
+
+        spin_unlock(&server->cb_lock);
+        _leave("");
+}
+
+/*
+ * dispatch a deferred give up callbacks operation
+ */
+void afs_dispatch_give_up_callbacks(struct work_struct *work)
+{
+        struct afs_server *server =
+                container_of(work, struct afs_server, cb_break_work.work);
+
+        _enter("");
+
+        /* tell the fileserver to discard the callback promises it has
+         * - in the event of ENOMEM or some other error, we just forget that we
+         *   had callbacks entirely, and the server will call us later to break
+         *   them
+         */
+        afs_fs_give_up_callbacks(server, &afs_async_call);
+}
+
+/*
+ * flush the outstanding callback breaks on a server
+ */
+void afs_flush_callback_breaks(struct afs_server *server)
+{
+        cancel_delayed_work(&server->cb_break_work);
+        queue_delayed_work(afs_callback_update_worker,
+                           &server->cb_break_work, 0);
+}
 
-                spin_unlock(&afs_cb_hash_lock);
-
-                if (inode) {
-                        /* we've found the record for this vnode */
-                        spin_lock(&vnode->lock);
-                        if (vnode->cb_server == server) {
-                                /* the callback _is_ on the calling server */
-                                vnode->cb_server = NULL;
-                                valid = 1;
-
-                                afs_kafstimod_del_timer(&vnode->cb_timeout);
-                                vnode->flags |= AFS_VNODE_CHANGED;
-
-                                spin_lock(&server->cb_lock);
-                                list_del_init(&vnode->cb_link);
-                                spin_unlock(&server->cb_lock);
-
-                                spin_lock(&afs_cb_hash_lock);
-                                list_del_init(&vnode->cb_hash_link);
-                                spin_unlock(&afs_cb_hash_lock);
-                        }
-                        spin_unlock(&vnode->lock);
-
-                        if (valid) {
-                                invalidate_remote_inode(inode);
-                                afs_put_server(server);
-                        }
-                        iput(inode);
+#if 0
+/*
+ * update a bunch of callbacks
+ */
+static void afs_callback_updater(struct work_struct *work)
+{
+        struct afs_server *server;
+        struct afs_vnode *vnode, *xvnode;
+        time_t now;
+        long timeout;
+        int ret;
+
+        server = container_of(work, struct afs_server, updater);
+
+        _enter("");
+
+        now = get_seconds();
+
+        /* find the first vnode to update */
+        spin_lock(&server->cb_lock);
+        for (;;) {
+                if (RB_EMPTY_ROOT(&server->cb_promises)) {
+                        spin_unlock(&server->cb_lock);
+                        _leave(" [nothing]");
+                        return;
                 }
+
+                vnode = rb_entry(rb_first(&server->cb_promises),
+                                 struct afs_vnode, cb_promise);
+                if (atomic_read(&vnode->usage) > 0)
+                        break;
+                rb_erase(&vnode->cb_promise, &server->cb_promises);
+                vnode->cb_promised = false;
         }
 
-        _leave(" = 0");
-        return 0;
-} /* end SRXAFSCM_CallBack() */
+        timeout = vnode->update_at - now;
+        if (timeout > 0) {
+                queue_delayed_work(afs_vnode_update_worker,
+                                   &afs_vnode_update, timeout * HZ);
+                spin_unlock(&server->cb_lock);
+                _leave(" [nothing]");
+                return;
+        }
+
+        list_del_init(&vnode->update);
+        atomic_inc(&vnode->usage);
+        spin_unlock(&server->cb_lock);
+
+        /* we can now perform the update */
+        _debug("update %s", vnode->vldb.name);
+        vnode->state = AFS_VL_UPDATING;
+        vnode->upd_rej_cnt = 0;
+        vnode->upd_busy_cnt = 0;
+
+        ret = afs_vnode_update_record(vl, &vldb);
+        switch (ret) {
+        case 0:
+                afs_vnode_apply_update(vl, &vldb);
+                vnode->state = AFS_VL_UPDATING;
+                break;
+        case -ENOMEDIUM:
+                vnode->state = AFS_VL_VOLUME_DELETED;
+                break;
+        default:
+                vnode->state = AFS_VL_UNCERTAIN;
+                break;
+        }
+
+        /* and then reschedule */
+        _debug("reschedule");
+        vnode->update_at = get_seconds() + afs_vnode_update_timeout;
+
+        spin_lock(&server->cb_lock);
+
+        if (!list_empty(&server->cb_promises)) {
+                /* next update in 10 minutes, but wait at least 1 second more
+                 * than the newest record already queued so that we don't spam
+                 * the VL server suddenly with lots of requests
+                 */
+                xvnode = list_entry(server->cb_promises.prev,
+                                    struct afs_vnode, update);
+                if (vnode->update_at <= xvnode->update_at)
+                        vnode->update_at = xvnode->update_at + 1;
+                xvnode = list_entry(server->cb_promises.next,
+                                    struct afs_vnode, update);
+                timeout = xvnode->update_at - now;
+                if (timeout < 0)
+                        timeout = 0;
+        } else {
+                timeout = afs_vnode_update_timeout;
+        }
+
+        list_add_tail(&vnode->update, &server->cb_promises);
+
+        _debug("timeout %ld", timeout);
+        queue_delayed_work(afs_vnode_update_worker,
+                           &afs_vnode_update, timeout * HZ);
+        spin_unlock(&server->cb_lock);
+        afs_put_vnode(vl);
+}
+#endif
+
+/*
+ * initialise the callback update process
+ */
+int __init afs_callback_update_init(void)
+{
+        afs_callback_update_worker =
+                create_singlethread_workqueue("kafs_callbackd");
+        return afs_callback_update_worker ? 0 : -ENOMEM;
+}
 
-/*****************************************************************************/
 /*
- * allow the fileserver to see if the cache manager is still alive
+ * shut down the callback update process
  */
-int SRXAFSCM_Probe(struct afs_server *server)
+void __exit afs_callback_update_kill(void)
 {
-        _debug("SRXAFSCM_Probe(%p)\n", server);
-        return 0;
-} /* end SRXAFSCM_Probe() */
+        destroy_workqueue(afs_callback_update_worker);
+}