WSL2-Linux-Kernel/fs/afs/vnode.c

396 строки
9.8 KiB
C

/* vnode.c: AFS vnode management
*
* Copyright (C) 2002 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 <linux/pagemap.h>
#include "volume.h"
#include "cell.h"
#include "cmservice.h"
#include "fsclient.h"
#include "vlclient.h"
#include "vnode.h"
#include "internal.h"
static void afs_vnode_cb_timed_out(struct afs_timer *timer);
struct afs_timer_ops afs_vnode_cb_timed_out_ops = {
.timed_out = afs_vnode_cb_timed_out,
};
#ifdef AFS_CACHING_SUPPORT
static cachefs_match_val_t afs_vnode_cache_match(void *target,
const void *entry);
static void afs_vnode_cache_update(void *source, void *entry);
struct cachefs_index_def afs_vnode_cache_index_def = {
.name = "vnode",
.data_size = sizeof(struct afs_cache_vnode),
.keys[0] = { CACHEFS_INDEX_KEYS_BIN, 4 },
.match = afs_vnode_cache_match,
.update = afs_vnode_cache_update,
};
#endif
/*****************************************************************************/
/*
* handle a callback timing out
* TODO: retain a ref to vnode struct for an outstanding callback timeout
*/
static void afs_vnode_cb_timed_out(struct afs_timer *timer)
{
struct afs_server *oldserver;
struct afs_vnode *vnode;
vnode = list_entry(timer, struct afs_vnode, cb_timeout);
_enter("%p", vnode);
/* set the changed flag in the vnode and release the server */
spin_lock(&vnode->lock);
oldserver = xchg(&vnode->cb_server, NULL);
if (oldserver) {
vnode->flags |= AFS_VNODE_CHANGED;
spin_lock(&afs_cb_hash_lock);
list_del_init(&vnode->cb_hash_link);
spin_unlock(&afs_cb_hash_lock);
spin_lock(&oldserver->cb_lock);
list_del_init(&vnode->cb_link);
spin_unlock(&oldserver->cb_lock);
}
spin_unlock(&vnode->lock);
afs_put_server(oldserver);
_leave("");
} /* end afs_vnode_cb_timed_out() */
/*****************************************************************************/
/*
* 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);
vnode->flags &= ~AFS_VNODE_CHANGED;
if (ret == 0) {
/* adjust the callback timeout appropriately */
afs_kafstimod_add_timer(&vnode->cb_timeout,
vnode->cb_expiry * HZ);
spin_lock(&afs_cb_hash_lock);
list_del(&vnode->cb_hash_link);
list_add_tail(&vnode->cb_hash_link,
&afs_cb_hash(server, &vnode->fid));
spin_unlock(&afs_cb_hash_lock);
/* swap ref to old callback server with that for new callback
* server */
oldserver = xchg(&vnode->cb_server, server);
if (oldserver != server) {
if (oldserver) {
spin_lock(&oldserver->cb_lock);
list_del_init(&vnode->cb_link);
spin_unlock(&oldserver->cb_lock);
}
afs_get_server(server);
spin_lock(&server->cb_lock);
list_add_tail(&vnode->cb_link, &server->cb_promises);
spin_unlock(&server->cb_lock);
}
else {
/* same server */
oldserver = NULL;
}
}
else if (ret == -ENOENT) {
/* the file was deleted - clear the callback timeout */
oldserver = xchg(&vnode->cb_server, NULL);
afs_kafstimod_del_timer(&vnode->cb_timeout);
_debug("got NOENT from server - marking file deleted");
vnode->flags |= AFS_VNODE_DELETED;
}
vnode->update_cnt--;
spin_unlock(&vnode->lock);
wake_up_all(&vnode->update_waitq);
afs_put_server(oldserver);
_leave("");
} /* end afs_vnode_finalise_status_update() */
/*****************************************************************************/
/*
* 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_server *server;
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 (!(vnode->flags & AFS_VNODE_CHANGED) && vnode->cb_server) {
_leave(" [unchanged]");
return 0;
}
if (vnode->flags & AFS_VNODE_DELETED) {
_leave(" [deleted]");
return -ENOENT;
}
spin_lock(&vnode->lock);
if (!(vnode->flags & AFS_VNODE_CHANGED)) {
spin_unlock(&vnode->lock);
_leave(" [unchanged]");
return 0;
}
if (vnode->update_cnt > 0) {
/* someone else started a fetch */
set_current_state(TASK_UNINTERRUPTIBLE);
add_wait_queue(&vnode->update_waitq, &myself);
/* wait for the status to be updated */
for (;;) {
if (!(vnode->flags & AFS_VNODE_CHANGED))
break;
if (vnode->flags & AFS_VNODE_DELETED)
break;
/* 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 vnode->flags & AFS_VNODE_DELETED ? -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 */
ret = afs_volume_pick_fileserver(vnode->volume, &server);
if (ret<0)
return ret;
_debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));
ret = afs_rxfs_fetch_file_status(server, vnode, NULL);
} while (!afs_volume_release_fileserver(vnode->volume, server, ret));
/* adjust the flags */
afs_vnode_finalise_status_update(vnode, server, ret);
_leave(" = %d", ret);
return ret;
} /* end afs_vnode_fetch_status() */
/*****************************************************************************/
/*
* fetch file data from the volume
* - TODO implement caching and server failover
*/
int afs_vnode_fetch_data(struct afs_vnode *vnode,
struct afs_rxfs_fetch_descriptor *desc)
{
struct afs_server *server;
int ret;
_enter("%s,{%u,%u,%u}",
vnode->volume->vlocation->vldb.name,
vnode->fid.vid,
vnode->fid.vnode,
vnode->fid.unique);
/* 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 */
ret = afs_volume_pick_fileserver(vnode->volume, &server);
if (ret < 0)
return ret;
_debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));
ret = afs_rxfs_fetch_file_data(server, vnode, desc, NULL);
} while (!afs_volume_release_fileserver(vnode->volume, server, ret));
/* adjust the flags */
afs_vnode_finalise_status_update(vnode, server, ret);
_leave(" = %d", ret);
return ret;
} /* end afs_vnode_fetch_data() */
/*****************************************************************************/
/*
* break any outstanding callback on a vnode
* - only relevent to server that issued it
*/
int afs_vnode_give_up_callback(struct afs_vnode *vnode)
{
struct afs_server *server;
int ret;
_enter("%s,{%u,%u,%u}",
vnode->volume->vlocation->vldb.name,
vnode->fid.vid,
vnode->fid.vnode,
vnode->fid.unique);
spin_lock(&afs_cb_hash_lock);
list_del_init(&vnode->cb_hash_link);
spin_unlock(&afs_cb_hash_lock);
/* set the changed flag in the vnode and release the server */
spin_lock(&vnode->lock);
afs_kafstimod_del_timer(&vnode->cb_timeout);
server = xchg(&vnode->cb_server, NULL);
if (server) {
vnode->flags |= AFS_VNODE_CHANGED;
spin_lock(&server->cb_lock);
list_del_init(&vnode->cb_link);
spin_unlock(&server->cb_lock);
}
spin_unlock(&vnode->lock);
ret = 0;
if (server) {
ret = afs_rxfs_give_up_callback(server, vnode);
afs_put_server(server);
}
_leave(" = %d", ret);
return ret;
} /* end afs_vnode_give_up_callback() */
/*****************************************************************************/
/*
* match a vnode record stored in the cache
*/
#ifdef AFS_CACHING_SUPPORT
static cachefs_match_val_t afs_vnode_cache_match(void *target,
const void *entry)
{
const struct afs_cache_vnode *cvnode = entry;
struct afs_vnode *vnode = target;
_enter("{%x,%x,%Lx},{%x,%x,%Lx}",
vnode->fid.vnode,
vnode->fid.unique,
vnode->status.version,
cvnode->vnode_id,
cvnode->vnode_unique,
cvnode->data_version);
if (vnode->fid.vnode != cvnode->vnode_id) {
_leave(" = FAILED");
return CACHEFS_MATCH_FAILED;
}
if (vnode->fid.unique != cvnode->vnode_unique ||
vnode->status.version != cvnode->data_version) {
_leave(" = DELETE");
return CACHEFS_MATCH_SUCCESS_DELETE;
}
_leave(" = SUCCESS");
return CACHEFS_MATCH_SUCCESS;
} /* end afs_vnode_cache_match() */
#endif
/*****************************************************************************/
/*
* update a vnode record stored in the cache
*/
#ifdef AFS_CACHING_SUPPORT
static void afs_vnode_cache_update(void *source, void *entry)
{
struct afs_cache_vnode *cvnode = entry;
struct afs_vnode *vnode = source;
_enter("");
cvnode->vnode_id = vnode->fid.vnode;
cvnode->vnode_unique = vnode->fid.unique;
cvnode->data_version = vnode->status.version;
} /* end afs_vnode_cache_update() */
#endif