/* AFS vnode management
 *
 * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include "internal.h"

#if 0
static noinline bool dump_tree_aux(struct rb_node *node, struct rb_node *parent,
                                   int depth, char lr)
{
        struct afs_vnode *vnode;
        bool bad = false;

        if (!node)
                return false;

        if (node->rb_left)
                bad = dump_tree_aux(node->rb_left, node, depth + 2, '/');

        vnode = rb_entry(node, struct afs_vnode, cb_promise);
        _debug("%c %*.*s%c%p {%d}",
               rb_is_red(node) ? 'R' : 'B',
               depth, depth, "", lr,
               vnode, vnode->cb_expires_at);
        if (rb_parent(node) != parent) {
                printk("BAD: %p != %p\n", rb_parent(node), parent);
                bad = true;
        }

        if (node->rb_right)
                bad |= dump_tree_aux(node->rb_right, node, depth + 2, '\\');

        return bad;
}

static noinline void dump_tree(const char *name, struct afs_server *server)
{
        _enter("%s", name);
        if (dump_tree_aux(server->cb_promises.rb_node, NULL, 0, '-'))
                BUG();
}
#endif

/*
 * insert a vnode into the backing server's vnode tree
 */
static void afs_install_vnode(struct afs_vnode *vnode,
                              struct afs_server *server)
{
        struct afs_server *old_server = vnode->server;
        struct afs_vnode *xvnode;
        struct rb_node *parent, **p;

        _enter("%p,%p", vnode, server);

        if (old_server) {
                spin_lock(&old_server->fs_lock);
                rb_erase(&vnode->server_rb, &old_server->fs_vnodes);
                spin_unlock(&old_server->fs_lock);
        }

        afs_get_server(server);
        vnode->server = server;
        afs_put_server(old_server);

        /* insert into the server's vnode tree in FID order */
        spin_lock(&server->fs_lock);

        parent = NULL;
        p = &server->fs_vnodes.rb_node;
        while (*p) {
                parent = *p;
                xvnode = rb_entry(parent, struct afs_vnode, server_rb);
                if (vnode->fid.vid < xvnode->fid.vid)
                        p = &(*p)->rb_left;
                else if (vnode->fid.vid > xvnode->fid.vid)
                        p = &(*p)->rb_right;
                else if (vnode->fid.vnode < xvnode->fid.vnode)
                        p = &(*p)->rb_left;
                else if (vnode->fid.vnode > xvnode->fid.vnode)
                        p = &(*p)->rb_right;
                else if (vnode->fid.unique < xvnode->fid.unique)
                        p = &(*p)->rb_left;
                else if (vnode->fid.unique > xvnode->fid.unique)
                        p = &(*p)->rb_right;
                else
                        BUG(); /* can't happen unless afs_iget() malfunctions */
        }

        rb_link_node(&vnode->server_rb, parent, p);
        rb_insert_color(&vnode->server_rb, &server->fs_vnodes);

        spin_unlock(&server->fs_lock);
        _leave("");
}

/*
 * insert a vnode into the promising server's update/expiration tree
 * - caller must hold vnode->lock
 */
static void afs_vnode_note_promise(struct afs_vnode *vnode,
                                   struct afs_server *server)
{
        struct afs_server *old_server;
        struct afs_vnode *xvnode;
        struct rb_node *parent, **p;

        _enter("%p,%p", vnode, server);

        ASSERT(server != NULL);

        old_server = vnode->server;
        if (vnode->cb_promised) {
                if (server == old_server &&
                    vnode->cb_expires == vnode->cb_expires_at) {
                        _leave(" [no change]");
                        return;
                }

                spin_lock(&old_server->cb_lock);
                if (vnode->cb_promised) {
                        _debug("delete");
                        rb_erase(&vnode->cb_promise, &old_server->cb_promises);
                        vnode->cb_promised = false;
                }
                spin_unlock(&old_server->cb_lock);
        }

        if (vnode->server != server)
                afs_install_vnode(vnode, server);

        vnode->cb_expires_at = vnode->cb_expires;
        _debug("PROMISE on %p {%lu}",
               vnode, (unsigned long) vnode->cb_expires_at);

        /* abuse an RB-tree to hold the expiration order (we may have multiple
         * items with the same expiration time) */
        spin_lock(&server->cb_lock);

        parent = NULL;
        p = &server->cb_promises.rb_node;
        while (*p) {
                parent = *p;
                xvnode = rb_entry(parent, struct afs_vnode, cb_promise);
                if (vnode->cb_expires_at < xvnode->cb_expires_at)
                        p = &(*p)->rb_left;
                else
                        p = &(*p)->rb_right;
        }

        rb_link_node(&vnode->cb_promise, parent, p);
        rb_insert_color(&vnode->cb_promise, &server->cb_promises);
        vnode->cb_promised = true;

        spin_unlock(&server->cb_lock);
        _leave("");
}

/*
 * handle remote file deletion by discarding the callback promise
 */
static void afs_vnode_deleted_remotely(struct afs_vnode *vnode)
{
        struct afs_server *server;

        _enter("{%p}", vnode->server);

        set_bit(AFS_VNODE_DELETED, &vnode->flags);

        server = vnode->server;
        if (server) {
                if (vnode->cb_promised) {
                        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);
                }

                spin_lock(&server->fs_lock);
                rb_erase(&vnode->server_rb, &server->fs_vnodes);
                spin_unlock(&server->fs_lock);

                vnode->server = NULL;
                afs_put_server(server);
        } else {
                ASSERT(!vnode->cb_promised);
        }

        _leave("");
}

/*
 * finish off updating the recorded status of a file after a successful
 * operation completion
 * - starts callback expiry timer
 * - adds to server's callback list
 */
void afs_vnode_finalise_status_update(struct afs_vnode *vnode,
                                      struct afs_server *server)
{
        struct afs_server *oldserver = NULL;

        _enter("%p,%p", vnode, server);

        spin_lock(&vnode->lock);
        clear_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
        afs_vnode_note_promise(vnode, server);
        vnode->update_cnt--;
        ASSERTCMP(vnode->update_cnt, >=, 0);
        spin_unlock(&vnode->lock);

        wake_up_all(&vnode->update_waitq);
        afs_put_server(oldserver);
        _leave("");
}

/*
 * finish off updating the recorded status of a file after an operation failed
 */
static void afs_vnode_status_update_failed(struct afs_vnode *vnode, int ret)
{
        _enter("{%x:%u},%d", vnode->fid.vid, vnode->fid.vnode, ret);

        spin_lock(&vnode->lock);

        clear_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);

        if (ret == -ENOENT) {
                /* the file was deleted on the server */
                _debug("got NOENT from server - marking file deleted");
                afs_vnode_deleted_remotely(vnode);
        }

        vnode->update_cnt--;
        ASSERTCMP(vnode->update_cnt, >=, 0);
        spin_unlock(&vnode->lock);

        wake_up_all(&vnode->update_waitq);
        _leave("");
}

/*
 * fetch file status from the volume
 * - don't issue a fetch if:
 *   - the changed bit is not set and there's a valid callback
 *   - there are any outstanding ops that will fetch the status
 * - TODO implement local caching
 */
int afs_vnode_fetch_status(struct afs_vnode *vnode,
                           struct afs_vnode *auth_vnode, struct key *key)
{
        struct afs_server *server;
        unsigned long acl_order;
        int ret;

        DECLARE_WAITQUEUE(myself, current);

        _enter("%s,{%x:%u.%u}",
               vnode->volume->vlocation->vldb.name,
               vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique);

        if (!test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
            vnode->cb_promised) {
                _leave(" [unchanged]");
                return 0;
        }

        if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
                _leave(" [deleted]");
                return -ENOENT;
        }

        acl_order = 0;
        if (auth_vnode)
                acl_order = auth_vnode->acl_order;

        spin_lock(&vnode->lock);

        if (!test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
            vnode->cb_promised) {
                spin_unlock(&vnode->lock);
                _leave(" [unchanged]");
                return 0;
        }

        ASSERTCMP(vnode->update_cnt, >=, 0);

        if (vnode->update_cnt > 0) {
                /* someone else started a fetch */
                _debug("wait on fetch %d", vnode->update_cnt);

                set_current_state(TASK_UNINTERRUPTIBLE);
                ASSERT(myself.func != NULL);
                add_wait_queue(&vnode->update_waitq, &myself);

                /* wait for the status to be updated */
                for (;;) {
                        if (!test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags))
                                break;
                        if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
                                break;

                        /* check to see if it got updated and invalidated all
                         * before we saw it */
                        if (vnode->update_cnt == 0) {
                                remove_wait_queue(&vnode->update_waitq,
                                                  &myself);
                                set_current_state(TASK_RUNNING);
                                goto get_anyway;
                        }

                        spin_unlock(&vnode->lock);

                        schedule();
                        set_current_state(TASK_UNINTERRUPTIBLE);

                        spin_lock(&vnode->lock);
                }

                remove_wait_queue(&vnode->update_waitq, &myself);
                spin_unlock(&vnode->lock);
                set_current_state(TASK_RUNNING);

                return test_bit(AFS_VNODE_DELETED, &vnode->flags) ?
                        -ENOENT : 0;
        }

get_anyway:
        /* okay... we're going to have to initiate the op */
        vnode->update_cnt++;

        spin_unlock(&vnode->lock);

        /* merge AFS status fetches and clear outstanding callback on this
         * vnode */
        do {
                /* pick a server to query */
                server = afs_volume_pick_fileserver(vnode);
                if (IS_ERR(server))
                        goto no_server;

                _debug("USING SERVER: %p{%08x}",
                       server, ntohl(server->addr.s_addr));

                ret = afs_fs_fetch_file_status(server, key, vnode, NULL,
                                               &afs_sync_call);

        } while (!afs_volume_release_fileserver(vnode, server, ret));

        /* adjust the flags */
        if (ret == 0) {
                _debug("adjust");
                if (auth_vnode)
                        afs_cache_permit(vnode, key, acl_order);
                afs_vnode_finalise_status_update(vnode, server);
                afs_put_server(server);
        } else {
                _debug("failed [%d]", ret);
                afs_vnode_status_update_failed(vnode, ret);
        }

        ASSERTCMP(vnode->update_cnt, >=, 0);

        _leave(" = %d [cnt %d]", ret, vnode->update_cnt);
        return ret;

no_server:
        spin_lock(&vnode->lock);
        vnode->update_cnt--;
        ASSERTCMP(vnode->update_cnt, >=, 0);
        spin_unlock(&vnode->lock);
        _leave(" = %ld [cnt %d]", PTR_ERR(server), vnode->update_cnt);
        return PTR_ERR(server);
}

/*
 * fetch file data from the volume
 * - TODO implement caching
 */
int afs_vnode_fetch_data(struct afs_vnode *vnode, struct key *key,
                         off_t offset, size_t length, struct page *page)
{
        struct afs_server *server;
        int ret;

        _enter("%s{%x:%u.%u},%x,,,",
               vnode->volume->vlocation->vldb.name,
               vnode->fid.vid,
               vnode->fid.vnode,
               vnode->fid.unique,
               key_serial(key));

        /* this op will fetch the status */
        spin_lock(&vnode->lock);
        vnode->update_cnt++;
        spin_unlock(&vnode->lock);

        /* merge in AFS status fetches and clear outstanding callback on this
         * vnode */
        do {
                /* pick a server to query */
                server = afs_volume_pick_fileserver(vnode);
                if (IS_ERR(server))
                        goto no_server;

                _debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));

                ret = afs_fs_fetch_data(server, key, vnode, offset, length,
                                        page, &afs_sync_call);

        } while (!afs_volume_release_fileserver(vnode, server, ret));

        /* adjust the flags */
        if (ret == 0) {
                afs_vnode_finalise_status_update(vnode, server);
                afs_put_server(server);
        } else {
                afs_vnode_status_update_failed(vnode, ret);
        }

        _leave(" = %d", ret);
        return ret;

no_server:
        spin_lock(&vnode->lock);
        vnode->update_cnt--;
        ASSERTCMP(vnode->update_cnt, >=, 0);
        spin_unlock(&vnode->lock);
        return PTR_ERR(server);
}

/*
 * make a file or a directory
 */
int afs_vnode_create(struct afs_vnode *vnode, struct key *key,
                     const char *name, umode_t mode, struct afs_fid *newfid,
                     struct afs_file_status *newstatus,
                     struct afs_callback *newcb, struct afs_server **_server)
{
        struct afs_server *server;
        int ret;

        _enter("%s{%x:%u.%u},%x,%s,,",
               vnode->volume->vlocation->vldb.name,
               vnode->fid.vid,
               vnode->fid.vnode,
               vnode->fid.unique,
               key_serial(key),
               name);

        /* this op will fetch the status on the directory we're creating in */
        spin_lock(&vnode->lock);
        vnode->update_cnt++;
        spin_unlock(&vnode->lock);

        do {
                /* pick a server to query */
                server = afs_volume_pick_fileserver(vnode);
                if (IS_ERR(server))
                        goto no_server;

                _debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));

                ret = afs_fs_create(server, key, vnode, name, mode, newfid,
                                    newstatus, newcb, &afs_sync_call);

        } while (!afs_volume_release_fileserver(vnode, server, ret));

        /* adjust the flags */
        if (ret == 0) {
                afs_vnode_finalise_status_update(vnode, server);
                *_server = server;
        } else {
                afs_vnode_status_update_failed(vnode, ret);
                *_server = NULL;
        }

        _leave(" = %d [cnt %d]", ret, vnode->update_cnt);
        return ret;

no_server:
        spin_lock(&vnode->lock);
        vnode->update_cnt--;
        ASSERTCMP(vnode->update_cnt, >=, 0);
        spin_unlock(&vnode->lock);
        _leave(" = %ld [cnt %d]", PTR_ERR(server), vnode->update_cnt);
        return PTR_ERR(server);
}

/*
 * remove a file or directory
 */
int afs_vnode_remove(struct afs_vnode *vnode, struct key *key, const char *name,
                     bool isdir)
{
        struct afs_server *server;
        int ret;

        _enter("%s{%x:%u.%u},%x,%s",
               vnode->volume->vlocation->vldb.name,
               vnode->fid.vid,
               vnode->fid.vnode,
               vnode->fid.unique,
               key_serial(key),
               name);

        /* this op will fetch the status on the directory we're removing from */
        spin_lock(&vnode->lock);
        vnode->update_cnt++;
        spin_unlock(&vnode->lock);

        do {
                /* pick a server to query */
                server = afs_volume_pick_fileserver(vnode);
                if (IS_ERR(server))
                        goto no_server;

                _debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));

                ret = afs_fs_remove(server, key, vnode, name, isdir,
                                    &afs_sync_call);

        } while (!afs_volume_release_fileserver(vnode, server, ret));

        /* adjust the flags */
        if (ret == 0) {
                afs_vnode_finalise_status_update(vnode, server);
                afs_put_server(server);
        } else {
                afs_vnode_status_update_failed(vnode, ret);
        }

        _leave(" = %d [cnt %d]", ret, vnode->update_cnt);
        return ret;

no_server:
        spin_lock(&vnode->lock);
        vnode->update_cnt--;
        ASSERTCMP(vnode->update_cnt, >=, 0);
        spin_unlock(&vnode->lock);
        _leave(" = %ld [cnt %d]", PTR_ERR(server), vnode->update_cnt);
        return PTR_ERR(server);
}

/*
 * create a hard link
 */
int afs_vnode_link(struct afs_vnode *dvnode, struct afs_vnode *vnode,
                          struct key *key, const char *name)
{
        struct afs_server *server;
        int ret;

        _enter("%s{%x:%u.%u},%s{%x:%u.%u},%x,%s",
               dvnode->volume->vlocation->vldb.name,
               dvnode->fid.vid,
               dvnode->fid.vnode,
               dvnode->fid.unique,
               vnode->volume->vlocation->vldb.name,
               vnode->fid.vid,
               vnode->fid.vnode,
               vnode->fid.unique,
               key_serial(key),
               name);

        /* this op will fetch the status on the directory we're removing from */
        spin_lock(&vnode->lock);
        vnode->update_cnt++;
        spin_unlock(&vnode->lock);
        spin_lock(&dvnode->lock);
        dvnode->update_cnt++;
        spin_unlock(&dvnode->lock);

        do {
                /* pick a server to query */
                server = afs_volume_pick_fileserver(dvnode);
                if (IS_ERR(server))
                        goto no_server;

                _debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));

                ret = afs_fs_link(server, key, dvnode, vnode, name,
                                  &afs_sync_call);

        } while (!afs_volume_release_fileserver(dvnode, server, ret));

        /* adjust the flags */
        if (ret == 0) {
                afs_vnode_finalise_status_update(vnode, server);
                afs_vnode_finalise_status_update(dvnode, server);
                afs_put_server(server);
        } else {
                afs_vnode_status_update_failed(vnode, ret);
                afs_vnode_status_update_failed(dvnode, ret);
        }

        _leave(" = %d [cnt %d]", ret, vnode->update_cnt);
        return ret;

no_server:
        spin_lock(&vnode->lock);
        vnode->update_cnt--;
        ASSERTCMP(vnode->update_cnt, >=, 0);
        spin_unlock(&vnode->lock);
        spin_lock(&dvnode->lock);
        dvnode->update_cnt--;
        ASSERTCMP(dvnode->update_cnt, >=, 0);
        spin_unlock(&dvnode->lock);
        _leave(" = %ld [cnt %d]", PTR_ERR(server), vnode->update_cnt);
        return PTR_ERR(server);
}

/*
 * create a symbolic link
 */
int afs_vnode_symlink(struct afs_vnode *vnode, struct key *key,
                      const char *name, const char *content,
                      struct afs_fid *newfid,
                      struct afs_file_status *newstatus,
                      struct afs_server **_server)
{
        struct afs_server *server;
        int ret;

        _enter("%s{%x:%u.%u},%x,%s,%s,,,",
               vnode->volume->vlocation->vldb.name,
               vnode->fid.vid,
               vnode->fid.vnode,
               vnode->fid.unique,
               key_serial(key),
               name, content);

        /* this op will fetch the status on the directory we're creating in */
        spin_lock(&vnode->lock);
        vnode->update_cnt++;
        spin_unlock(&vnode->lock);

        do {
                /* pick a server to query */
                server = afs_volume_pick_fileserver(vnode);
                if (IS_ERR(server))
                        goto no_server;

                _debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));

                ret = afs_fs_symlink(server, key, vnode, name, content,
                                     newfid, newstatus, &afs_sync_call);

        } while (!afs_volume_release_fileserver(vnode, server, ret));

        /* adjust the flags */
        if (ret == 0) {
                afs_vnode_finalise_status_update(vnode, server);
                *_server = server;
        } else {
                afs_vnode_status_update_failed(vnode, ret);
                *_server = NULL;
        }

        _leave(" = %d [cnt %d]", ret, vnode->update_cnt);
        return ret;

no_server:
        spin_lock(&vnode->lock);
        vnode->update_cnt--;
        ASSERTCMP(vnode->update_cnt, >=, 0);
        spin_unlock(&vnode->lock);
        _leave(" = %ld [cnt %d]", PTR_ERR(server), vnode->update_cnt);
        return PTR_ERR(server);
}

/*
 * rename a file
 */
int afs_vnode_rename(struct afs_vnode *orig_dvnode,
                     struct afs_vnode *new_dvnode,
                     struct key *key,
                     const char *orig_name,
                     const char *new_name)
{
        struct afs_server *server;
        int ret;

        _enter("%s{%x:%u.%u},%s{%u,%u,%u},%x,%s,%s",
               orig_dvnode->volume->vlocation->vldb.name,
               orig_dvnode->fid.vid,
               orig_dvnode->fid.vnode,
               orig_dvnode->fid.unique,
               new_dvnode->volume->vlocation->vldb.name,
               new_dvnode->fid.vid,
               new_dvnode->fid.vnode,
               new_dvnode->fid.unique,
               key_serial(key),
               orig_name,
               new_name);

        /* this op will fetch the status on both the directories we're dealing
         * with */
        spin_lock(&orig_dvnode->lock);
        orig_dvnode->update_cnt++;
        spin_unlock(&orig_dvnode->lock);
        if (new_dvnode != orig_dvnode) {
                spin_lock(&new_dvnode->lock);
                new_dvnode->update_cnt++;
                spin_unlock(&new_dvnode->lock);
        }

        do {
                /* pick a server to query */
                server = afs_volume_pick_fileserver(orig_dvnode);
                if (IS_ERR(server))
                        goto no_server;

                _debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));

                ret = afs_fs_rename(server, key, orig_dvnode, orig_name,
                                    new_dvnode, new_name, &afs_sync_call);

        } while (!afs_volume_release_fileserver(orig_dvnode, server, ret));

        /* adjust the flags */
        if (ret == 0) {
                afs_vnode_finalise_status_update(orig_dvnode, server);
                if (new_dvnode != orig_dvnode)
                        afs_vnode_finalise_status_update(new_dvnode, server);
                afs_put_server(server);
        } else {
                afs_vnode_status_update_failed(orig_dvnode, ret);
                if (new_dvnode != orig_dvnode)
                        afs_vnode_status_update_failed(new_dvnode, ret);
        }

        _leave(" = %d [cnt %d]", ret, orig_dvnode->update_cnt);
        return ret;

no_server:
        spin_lock(&orig_dvnode->lock);
        orig_dvnode->update_cnt--;
        ASSERTCMP(orig_dvnode->update_cnt, >=, 0);
        spin_unlock(&orig_dvnode->lock);
        if (new_dvnode != orig_dvnode) {
                spin_lock(&new_dvnode->lock);
                new_dvnode->update_cnt--;
                ASSERTCMP(new_dvnode->update_cnt, >=, 0);
                spin_unlock(&new_dvnode->lock);
        }
        _leave(" = %ld [cnt %d]", PTR_ERR(server), orig_dvnode->update_cnt);
        return PTR_ERR(server);
}

/*
 * write to a file
 */
int afs_vnode_store_data(struct afs_writeback *wb, pgoff_t first, pgoff_t last,
                         unsigned offset, unsigned to)
{
        struct afs_server *server;
        struct afs_vnode *vnode = wb->vnode;
        int ret;

        _enter("%s{%x:%u.%u},%x,%lx,%lx,%x,%x",
               vnode->volume->vlocation->vldb.name,
               vnode->fid.vid,
               vnode->fid.vnode,
               vnode->fid.unique,
               key_serial(wb->key),
               first, last, offset, to);

        /* this op will fetch the status */
        spin_lock(&vnode->lock);
        vnode->update_cnt++;
        spin_unlock(&vnode->lock);

        do {
                /* pick a server to query */
                server = afs_volume_pick_fileserver(vnode);
                if (IS_ERR(server))
                        goto no_server;

                _debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));

                ret = afs_fs_store_data(server, wb, first, last, offset, to,
                                        &afs_sync_call);

        } while (!afs_volume_release_fileserver(vnode, server, ret));

        /* adjust the flags */
        if (ret == 0) {
                afs_vnode_finalise_status_update(vnode, server);
                afs_put_server(server);
        } else {
                afs_vnode_status_update_failed(vnode, ret);
        }

        _leave(" = %d", ret);
        return ret;

no_server:
        spin_lock(&vnode->lock);
        vnode->update_cnt--;
        ASSERTCMP(vnode->update_cnt, >=, 0);
        spin_unlock(&vnode->lock);
        return PTR_ERR(server);
}

/*
 * set the attributes on a file
 */
int afs_vnode_setattr(struct afs_vnode *vnode, struct key *key,
                      struct iattr *attr)
{
        struct afs_server *server;
        int ret;

        _enter("%s{%x:%u.%u},%x",
               vnode->volume->vlocation->vldb.name,
               vnode->fid.vid,
               vnode->fid.vnode,
               vnode->fid.unique,
               key_serial(key));

        /* this op will fetch the status */
        spin_lock(&vnode->lock);
        vnode->update_cnt++;
        spin_unlock(&vnode->lock);

        do {
                /* pick a server to query */
                server = afs_volume_pick_fileserver(vnode);
                if (IS_ERR(server))
                        goto no_server;

                _debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));

                ret = afs_fs_setattr(server, key, vnode, attr, &afs_sync_call);

        } while (!afs_volume_release_fileserver(vnode, server, ret));

        /* adjust the flags */
        if (ret == 0) {
                afs_vnode_finalise_status_update(vnode, server);
                afs_put_server(server);
        } else {
                afs_vnode_status_update_failed(vnode, ret);
        }

        _leave(" = %d", ret);
        return ret;

no_server:
        spin_lock(&vnode->lock);
        vnode->update_cnt--;
        ASSERTCMP(vnode->update_cnt, >=, 0);
        spin_unlock(&vnode->lock);
        return PTR_ERR(server);
}

/*
 * get the status of a volume
 */
int afs_vnode_get_volume_status(struct afs_vnode *vnode, struct key *key,
                                struct afs_volume_status *vs)
{
        struct afs_server *server;
        int ret;

        _enter("%s{%x:%u.%u},%x,",
               vnode->volume->vlocation->vldb.name,
               vnode->fid.vid,
               vnode->fid.vnode,
               vnode->fid.unique,
               key_serial(key));

        do {
                /* pick a server to query */
                server = afs_volume_pick_fileserver(vnode);
                if (IS_ERR(server))
                        goto no_server;

                _debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));

                ret = afs_fs_get_volume_status(server, key, vnode, vs, &afs_sync_call);

        } while (!afs_volume_release_fileserver(vnode, server, ret));

        /* adjust the flags */
        if (ret == 0)
                afs_put_server(server);

        _leave(" = %d", ret);
        return ret;

no_server:
        return PTR_ERR(server);
}

/*
 * get a lock on a file
 */
int afs_vnode_set_lock(struct afs_vnode *vnode, struct key *key,
                       afs_lock_type_t type)
{
        struct afs_server *server;
        int ret;

        _enter("%s{%x:%u.%u},%x,%u",
               vnode->volume->vlocation->vldb.name,
               vnode->fid.vid,
               vnode->fid.vnode,
               vnode->fid.unique,
               key_serial(key), type);

        do {
                /* pick a server to query */
                server = afs_volume_pick_fileserver(vnode);
                if (IS_ERR(server))
                        goto no_server;

                _debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));

                ret = afs_fs_set_lock(server, key, vnode, type, &afs_sync_call);

        } while (!afs_volume_release_fileserver(vnode, server, ret));

        /* adjust the flags */
        if (ret == 0)
                afs_put_server(server);

        _leave(" = %d", ret);
        return ret;

no_server:
        return PTR_ERR(server);
}

/*
 * extend a lock on a file
 */
int afs_vnode_extend_lock(struct afs_vnode *vnode, struct key *key)
{
        struct afs_server *server;
        int ret;

        _enter("%s{%x:%u.%u},%x",
               vnode->volume->vlocation->vldb.name,
               vnode->fid.vid,
               vnode->fid.vnode,
               vnode->fid.unique,
               key_serial(key));

        do {
                /* pick a server to query */
                server = afs_volume_pick_fileserver(vnode);
                if (IS_ERR(server))
                        goto no_server;

                _debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));

                ret = afs_fs_extend_lock(server, key, vnode, &afs_sync_call);

        } while (!afs_volume_release_fileserver(vnode, server, ret));

        /* adjust the flags */
        if (ret == 0)
                afs_put_server(server);

        _leave(" = %d", ret);
        return ret;

no_server:
        return PTR_ERR(server);
}

/*
 * release a lock on a file
 */
int afs_vnode_release_lock(struct afs_vnode *vnode, struct key *key)
{
        struct afs_server *server;
        int ret;

        _enter("%s{%x:%u.%u},%x",
               vnode->volume->vlocation->vldb.name,
               vnode->fid.vid,
               vnode->fid.vnode,

               vnode->fid.unique,
               key_serial(key));

        do {
                /* pick a server to query */
                server = afs_volume_pick_fileserver(vnode);
                if (IS_ERR(server))
                        goto no_server;

                _debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));

                ret = afs_fs_release_lock(server, key, vnode, &afs_sync_call);

        } while (!afs_volume_release_fileserver(vnode, server, ret));

        /* adjust the flags */
        if (ret == 0)
                afs_put_server(server);

        _leave(" = %d", ret);
        return ret;

no_server:
        return PTR_ERR(server);
}