linux/fs/afs/vnode.c

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/* 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/slab.h>
#include <linux/fs.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);
kdebug("%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)
{
kenter("%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;
set_bit(AFS_VNODE_DELETED, &vnode->flags);
server = vnode->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);
}
afs_put_server(server);
}
/*
* finish off updating the recorded status of a file
* - starts callback expiry timer
* - adds to server's callback list
*/
static void afs_vnode_finalise_status_update(struct afs_vnode *vnode,
struct afs_server *server,
int ret)
{
struct afs_server *oldserver = NULL;
_enter("%p,%p,%d", vnode, server, ret);
spin_lock(&vnode->lock);
clear_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
switch (ret) {
case 0:
afs_vnode_note_promise(vnode, server);
break;
case -ENOENT:
/* the file was deleted on the server */
_debug("got NOENT from server - marking file deleted");
afs_vnode_deleted_remotely(vnode);
break;
default:
break;
}
vnode->update_cnt--;
spin_unlock(&vnode->lock);
wake_up_all(&vnode->update_waitq);
afs_put_server(oldserver);
_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,{%u,%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;
}
if (vnode->update_cnt > 0) {
/* someone else started a fetch */
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))
return PTR_ERR(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 && auth_vnode)
afs_cache_permit(vnode, key, acl_order);
afs_vnode_finalise_status_update(vnode, server, ret);
_leave(" = %d", ret);
return ret;
}
/*
* fetch file data from the volume
* - TODO implement caching and server failover
*/
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{%u,%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))
return PTR_ERR(server);
_debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));
ret = afs_fs_fetch_data(server, key, vnode, offset, length,
page, NULL, &afs_sync_call);
} while (!afs_volume_release_fileserver(vnode, server, ret));
/* adjust the flags */
afs_vnode_finalise_status_update(vnode, server, ret);
_leave(" = %d", ret);
return ret;
}