553 lines
12 KiB
C
553 lines
12 KiB
C
/* AFS cell and server record management
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*
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* Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <rxrpc/peer.h>
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#include <rxrpc/connection.h>
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#include "volume.h"
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#include "cell.h"
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#include "server.h"
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#include "transport.h"
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#include "vlclient.h"
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#include "kafstimod.h"
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#include "super.h"
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#include "internal.h"
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DECLARE_RWSEM(afs_proc_cells_sem);
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LIST_HEAD(afs_proc_cells);
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static struct list_head afs_cells = LIST_HEAD_INIT(afs_cells);
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static DEFINE_RWLOCK(afs_cells_lock);
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static DECLARE_RWSEM(afs_cells_sem); /* add/remove serialisation */
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static struct afs_cell *afs_cell_root;
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#ifdef AFS_CACHING_SUPPORT
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static cachefs_match_val_t afs_cell_cache_match(void *target,
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const void *entry);
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static void afs_cell_cache_update(void *source, void *entry);
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struct cachefs_index_def afs_cache_cell_index_def = {
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.name = "cell_ix",
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.data_size = sizeof(struct afs_cache_cell),
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.keys[0] = { CACHEFS_INDEX_KEYS_ASCIIZ, 64 },
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.match = afs_cell_cache_match,
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.update = afs_cell_cache_update,
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};
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#endif
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/*
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* create a cell record
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* - "name" is the name of the cell
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* - "vllist" is a colon separated list of IP addresses in "a.b.c.d" format
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*/
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int afs_cell_create(const char *name, char *vllist, struct afs_cell **_cell)
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{
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struct afs_cell *cell;
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char *next;
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int ret;
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_enter("%s", name);
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BUG_ON(!name); /* TODO: want to look up "this cell" in the cache */
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/* allocate and initialise a cell record */
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cell = kmalloc(sizeof(struct afs_cell) + strlen(name) + 1, GFP_KERNEL);
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if (!cell) {
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_leave(" = -ENOMEM");
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return -ENOMEM;
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}
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down_write(&afs_cells_sem);
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memset(cell, 0, sizeof(struct afs_cell));
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atomic_set(&cell->usage, 0);
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INIT_LIST_HEAD(&cell->link);
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rwlock_init(&cell->sv_lock);
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INIT_LIST_HEAD(&cell->sv_list);
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INIT_LIST_HEAD(&cell->sv_graveyard);
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spin_lock_init(&cell->sv_gylock);
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init_rwsem(&cell->vl_sem);
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INIT_LIST_HEAD(&cell->vl_list);
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INIT_LIST_HEAD(&cell->vl_graveyard);
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spin_lock_init(&cell->vl_gylock);
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strcpy(cell->name,name);
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/* fill in the VL server list from the rest of the string */
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ret = -EINVAL;
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do {
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unsigned a, b, c, d;
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next = strchr(vllist, ':');
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if (next)
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*next++ = 0;
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if (sscanf(vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4)
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goto badaddr;
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if (a > 255 || b > 255 || c > 255 || d > 255)
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goto badaddr;
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cell->vl_addrs[cell->vl_naddrs++].s_addr =
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htonl((a << 24) | (b << 16) | (c << 8) | d);
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if (cell->vl_naddrs >= AFS_CELL_MAX_ADDRS)
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break;
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} while(vllist = next, vllist);
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/* add a proc dir for this cell */
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ret = afs_proc_cell_setup(cell);
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if (ret < 0)
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goto error;
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#ifdef AFS_CACHING_SUPPORT
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/* put it up for caching */
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cachefs_acquire_cookie(afs_cache_netfs.primary_index,
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&afs_vlocation_cache_index_def,
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cell,
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&cell->cache);
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#endif
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/* add to the cell lists */
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write_lock(&afs_cells_lock);
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list_add_tail(&cell->link, &afs_cells);
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write_unlock(&afs_cells_lock);
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down_write(&afs_proc_cells_sem);
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list_add_tail(&cell->proc_link, &afs_proc_cells);
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up_write(&afs_proc_cells_sem);
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*_cell = cell;
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up_write(&afs_cells_sem);
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_leave(" = 0 (%p)", cell);
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return 0;
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badaddr:
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printk(KERN_ERR "kAFS: bad VL server IP address: '%s'\n", vllist);
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error:
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up_write(&afs_cells_sem);
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kfree(cell);
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_leave(" = %d", ret);
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return ret;
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}
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/*
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* initialise the cell database from module parameters
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*/
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int afs_cell_init(char *rootcell)
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{
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struct afs_cell *old_root, *new_root;
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char *cp;
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int ret;
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_enter("");
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if (!rootcell) {
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/* module is loaded with no parameters, or built statically.
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* - in the future we might initialize cell DB here.
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*/
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_leave(" = 0 (but no root)");
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return 0;
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}
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cp = strchr(rootcell, ':');
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if (!cp) {
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printk(KERN_ERR "kAFS: no VL server IP addresses specified\n");
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_leave(" = %d (no colon)", -EINVAL);
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return -EINVAL;
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}
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/* allocate a cell record for the root cell */
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*cp++ = 0;
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ret = afs_cell_create(rootcell, cp, &new_root);
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if (ret < 0) {
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_leave(" = %d", ret);
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return ret;
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}
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/* as afs_put_cell() takes locks by itself, we have to do
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* a little gymnastics to be race-free.
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*/
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afs_get_cell(new_root);
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write_lock(&afs_cells_lock);
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while (afs_cell_root) {
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old_root = afs_cell_root;
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afs_cell_root = NULL;
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write_unlock(&afs_cells_lock);
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afs_put_cell(old_root);
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write_lock(&afs_cells_lock);
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}
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afs_cell_root = new_root;
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write_unlock(&afs_cells_lock);
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_leave(" = %d", ret);
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return ret;
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}
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/*
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* lookup a cell record
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*/
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int afs_cell_lookup(const char *name, unsigned namesz, struct afs_cell **_cell)
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{
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struct afs_cell *cell;
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int ret;
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_enter("\"%*.*s\",", namesz, namesz, name ? name : "");
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*_cell = NULL;
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if (name) {
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/* if the cell was named, look for it in the cell record list */
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ret = -ENOENT;
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cell = NULL;
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read_lock(&afs_cells_lock);
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list_for_each_entry(cell, &afs_cells, link) {
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if (strncmp(cell->name, name, namesz) == 0) {
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afs_get_cell(cell);
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goto found;
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}
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}
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cell = NULL;
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found:
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read_unlock(&afs_cells_lock);
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if (cell)
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ret = 0;
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} else {
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read_lock(&afs_cells_lock);
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cell = afs_cell_root;
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if (!cell) {
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/* this should not happen unless user tries to mount
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* when root cell is not set. Return an impossibly
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* bizzare errno to alert the user. Things like
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* ENOENT might be "more appropriate" but they happen
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* for other reasons.
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*/
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ret = -EDESTADDRREQ;
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} else {
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afs_get_cell(cell);
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ret = 0;
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}
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read_unlock(&afs_cells_lock);
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}
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*_cell = cell;
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_leave(" = %d (%p)", ret, cell);
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return ret;
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}
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/*
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* try and get a cell record
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*/
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struct afs_cell *afs_get_cell_maybe(struct afs_cell **_cell)
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{
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struct afs_cell *cell;
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write_lock(&afs_cells_lock);
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cell = *_cell;
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if (cell && !list_empty(&cell->link))
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afs_get_cell(cell);
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else
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cell = NULL;
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write_unlock(&afs_cells_lock);
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return cell;
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}
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/*
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* destroy a cell record
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*/
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void afs_put_cell(struct afs_cell *cell)
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{
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if (!cell)
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return;
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_enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name);
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/* sanity check */
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BUG_ON(atomic_read(&cell->usage) <= 0);
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/* to prevent a race, the decrement and the dequeue must be effectively
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* atomic */
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write_lock(&afs_cells_lock);
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if (likely(!atomic_dec_and_test(&cell->usage))) {
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write_unlock(&afs_cells_lock);
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_leave("");
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return;
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}
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write_unlock(&afs_cells_lock);
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BUG_ON(!list_empty(&cell->sv_list));
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BUG_ON(!list_empty(&cell->sv_graveyard));
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BUG_ON(!list_empty(&cell->vl_list));
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BUG_ON(!list_empty(&cell->vl_graveyard));
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_leave(" [unused]");
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}
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/*
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* destroy a cell record
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*/
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static void afs_cell_destroy(struct afs_cell *cell)
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{
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_enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name);
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/* to prevent a race, the decrement and the dequeue must be effectively
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* atomic */
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write_lock(&afs_cells_lock);
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/* sanity check */
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BUG_ON(atomic_read(&cell->usage) != 0);
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list_del_init(&cell->link);
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write_unlock(&afs_cells_lock);
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down_write(&afs_cells_sem);
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afs_proc_cell_remove(cell);
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down_write(&afs_proc_cells_sem);
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list_del_init(&cell->proc_link);
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up_write(&afs_proc_cells_sem);
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#ifdef AFS_CACHING_SUPPORT
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cachefs_relinquish_cookie(cell->cache, 0);
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#endif
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up_write(&afs_cells_sem);
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BUG_ON(!list_empty(&cell->sv_list));
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BUG_ON(!list_empty(&cell->sv_graveyard));
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BUG_ON(!list_empty(&cell->vl_list));
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BUG_ON(!list_empty(&cell->vl_graveyard));
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/* finish cleaning up the cell */
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kfree(cell);
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_leave(" [destroyed]");
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}
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/*
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* lookup the server record corresponding to an Rx RPC peer
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*/
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int afs_server_find_by_peer(const struct rxrpc_peer *peer,
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struct afs_server **_server)
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{
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struct afs_server *server;
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struct afs_cell *cell;
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_enter("%p{a=%08x},", peer, ntohl(peer->addr.s_addr));
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/* search the cell list */
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read_lock(&afs_cells_lock);
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list_for_each_entry(cell, &afs_cells, link) {
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_debug("? cell %s",cell->name);
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write_lock(&cell->sv_lock);
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/* check the active list */
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list_for_each_entry(server, &cell->sv_list, link) {
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_debug("?? server %08x", ntohl(server->addr.s_addr));
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if (memcmp(&server->addr, &peer->addr,
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sizeof(struct in_addr)) == 0)
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goto found_server;
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}
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/* check the inactive list */
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spin_lock(&cell->sv_gylock);
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list_for_each_entry(server, &cell->sv_graveyard, link) {
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_debug("?? dead server %08x",
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ntohl(server->addr.s_addr));
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if (memcmp(&server->addr, &peer->addr,
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sizeof(struct in_addr)) == 0)
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goto found_dead_server;
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}
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spin_unlock(&cell->sv_gylock);
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write_unlock(&cell->sv_lock);
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}
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read_unlock(&afs_cells_lock);
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_leave(" = -ENOENT");
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return -ENOENT;
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/* we found it in the graveyard - resurrect it */
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found_dead_server:
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list_move_tail(&server->link, &cell->sv_list);
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afs_get_server(server);
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afs_kafstimod_del_timer(&server->timeout);
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spin_unlock(&cell->sv_gylock);
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goto success;
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/* we found it - increment its ref count and return it */
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found_server:
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afs_get_server(server);
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success:
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write_unlock(&cell->sv_lock);
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read_unlock(&afs_cells_lock);
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*_server = server;
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_leave(" = 0 (s=%p c=%p)", server, cell);
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return 0;
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}
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/*
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* purge in-memory cell database on module unload or afs_init() failure
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* - the timeout daemon is stopped before calling this
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*/
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void afs_cell_purge(void)
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{
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struct afs_vlocation *vlocation;
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struct afs_cell *cell;
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_enter("");
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afs_put_cell(afs_cell_root);
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while (!list_empty(&afs_cells)) {
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cell = NULL;
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/* remove the next cell from the front of the list */
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write_lock(&afs_cells_lock);
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if (!list_empty(&afs_cells)) {
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cell = list_entry(afs_cells.next,
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struct afs_cell, link);
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list_del_init(&cell->link);
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}
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write_unlock(&afs_cells_lock);
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if (cell) {
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_debug("PURGING CELL %s (%d)",
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cell->name, atomic_read(&cell->usage));
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BUG_ON(!list_empty(&cell->sv_list));
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BUG_ON(!list_empty(&cell->vl_list));
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/* purge the cell's VL graveyard list */
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_debug(" - clearing VL graveyard");
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spin_lock(&cell->vl_gylock);
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while (!list_empty(&cell->vl_graveyard)) {
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vlocation = list_entry(cell->vl_graveyard.next,
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struct afs_vlocation,
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link);
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list_del_init(&vlocation->link);
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afs_kafstimod_del_timer(&vlocation->timeout);
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spin_unlock(&cell->vl_gylock);
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afs_vlocation_do_timeout(vlocation);
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/* TODO: race if move to use krxtimod instead
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* of kafstimod */
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spin_lock(&cell->vl_gylock);
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}
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spin_unlock(&cell->vl_gylock);
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/* purge the cell's server graveyard list */
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_debug(" - clearing server graveyard");
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spin_lock(&cell->sv_gylock);
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while (!list_empty(&cell->sv_graveyard)) {
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struct afs_server *server;
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server = list_entry(cell->sv_graveyard.next,
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struct afs_server, link);
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list_del_init(&server->link);
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afs_kafstimod_del_timer(&server->timeout);
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spin_unlock(&cell->sv_gylock);
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afs_server_do_timeout(server);
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spin_lock(&cell->sv_gylock);
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}
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spin_unlock(&cell->sv_gylock);
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/* now the cell should be left with no references */
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afs_cell_destroy(cell);
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}
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}
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_leave("");
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}
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/*
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* match a cell record obtained from the cache
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*/
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#ifdef AFS_CACHING_SUPPORT
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static cachefs_match_val_t afs_cell_cache_match(void *target,
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const void *entry)
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{
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const struct afs_cache_cell *ccell = entry;
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struct afs_cell *cell = target;
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_enter("{%s},{%s}", ccell->name, cell->name);
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if (strncmp(ccell->name, cell->name, sizeof(ccell->name)) == 0) {
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_leave(" = SUCCESS");
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return CACHEFS_MATCH_SUCCESS;
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}
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_leave(" = FAILED");
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return CACHEFS_MATCH_FAILED;
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}
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#endif
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/*
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* update a cell record in the cache
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*/
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#ifdef AFS_CACHING_SUPPORT
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static void afs_cell_cache_update(void *source, void *entry)
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{
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struct afs_cache_cell *ccell = entry;
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struct afs_cell *cell = source;
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_enter("%p,%p", source, entry);
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strncpy(ccell->name, cell->name, sizeof(ccell->name));
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memcpy(ccell->vl_servers,
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cell->vl_addrs,
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min(sizeof(ccell->vl_servers), sizeof(cell->vl_addrs)));
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}
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#endif
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