diff options
Diffstat (limited to 'fs/afs/cell.c')
| -rw-r--r-- | fs/afs/cell.c | 569 |
1 files changed, 569 insertions, 0 deletions
diff --git a/fs/afs/cell.c b/fs/afs/cell.c new file mode 100644 index 00000000000..009a9ae88d6 --- /dev/null +++ b/fs/afs/cell.c @@ -0,0 +1,569 @@ +/* cell.c: AFS cell and server record 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/module.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <rxrpc/peer.h> +#include <rxrpc/connection.h> +#include "volume.h" +#include "cell.h" +#include "server.h" +#include "transport.h" +#include "vlclient.h" +#include "kafstimod.h" +#include "super.h" +#include "internal.h" + +DECLARE_RWSEM(afs_proc_cells_sem); +LIST_HEAD(afs_proc_cells); + +static struct list_head afs_cells = LIST_HEAD_INIT(afs_cells); +static DEFINE_RWLOCK(afs_cells_lock); +static DECLARE_RWSEM(afs_cells_sem); /* add/remove serialisation */ +static struct afs_cell *afs_cell_root; + +#ifdef AFS_CACHING_SUPPORT +static cachefs_match_val_t afs_cell_cache_match(void *target, + const void *entry); +static void afs_cell_cache_update(void *source, void *entry); + +struct cachefs_index_def afs_cache_cell_index_def = { + .name = "cell_ix", + .data_size = sizeof(struct afs_cache_cell), + .keys[0] = { CACHEFS_INDEX_KEYS_ASCIIZ, 64 }, + .match = afs_cell_cache_match, + .update = afs_cell_cache_update, +}; +#endif + +/*****************************************************************************/ +/* + * create a cell record + * - "name" is the name of the cell + * - "vllist" is a colon separated list of IP addresses in "a.b.c.d" format + */ +int afs_cell_create(const char *name, char *vllist, struct afs_cell **_cell) +{ + struct afs_cell *cell; + char *next; + int ret; + + _enter("%s", name); + + BUG_ON(!name); /* TODO: want to look up "this cell" in the cache */ + + /* allocate and initialise a cell record */ + cell = kmalloc(sizeof(struct afs_cell) + strlen(name) + 1, GFP_KERNEL); + if (!cell) { + _leave(" = -ENOMEM"); + return -ENOMEM; + } + + down_write(&afs_cells_sem); + + memset(cell, 0, sizeof(struct afs_cell)); + atomic_set(&cell->usage, 0); + + INIT_LIST_HEAD(&cell->link); + + rwlock_init(&cell->sv_lock); + INIT_LIST_HEAD(&cell->sv_list); + INIT_LIST_HEAD(&cell->sv_graveyard); + spin_lock_init(&cell->sv_gylock); + + init_rwsem(&cell->vl_sem); + INIT_LIST_HEAD(&cell->vl_list); + INIT_LIST_HEAD(&cell->vl_graveyard); + spin_lock_init(&cell->vl_gylock); + + strcpy(cell->name,name); + + /* fill in the VL server list from the rest of the string */ + ret = -EINVAL; + do { + unsigned a, b, c, d; + + next = strchr(vllist, ':'); + if (next) + *next++ = 0; + + if (sscanf(vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4) + goto badaddr; + + if (a > 255 || b > 255 || c > 255 || d > 255) + goto badaddr; + + cell->vl_addrs[cell->vl_naddrs++].s_addr = + htonl((a << 24) | (b << 16) | (c << 8) | d); + + if (cell->vl_naddrs >= AFS_CELL_MAX_ADDRS) + break; + + } while(vllist = next, vllist); + + /* add a proc dir for this cell */ + ret = afs_proc_cell_setup(cell); + if (ret < 0) + goto error; + +#ifdef AFS_CACHING_SUPPORT + /* put it up for caching */ + cachefs_acquire_cookie(afs_cache_netfs.primary_index, + &afs_vlocation_cache_index_def, + cell, + &cell->cache); +#endif + + /* add to the cell lists */ + write_lock(&afs_cells_lock); + list_add_tail(&cell->link, &afs_cells); + write_unlock(&afs_cells_lock); + + down_write(&afs_proc_cells_sem); + list_add_tail(&cell->proc_link, &afs_proc_cells); + up_write(&afs_proc_cells_sem); + + *_cell = cell; + up_write(&afs_cells_sem); + + _leave(" = 0 (%p)", cell); + return 0; + + badaddr: + printk(KERN_ERR "kAFS: bad VL server IP address: '%s'\n", vllist); + error: + up_write(&afs_cells_sem); + kfree(cell); + _leave(" = %d", ret); + return ret; +} /* end afs_cell_create() */ + +/*****************************************************************************/ +/* + * initialise the cell database from module parameters + */ +int afs_cell_init(char *rootcell) +{ + struct afs_cell *old_root, *new_root; + char *cp; + int ret; + + _enter(""); + + if (!rootcell) { + /* module is loaded with no parameters, or built statically. + * - in the future we might initialize cell DB here. + */ + _leave(" = 0 (but no root)"); + return 0; + } + + cp = strchr(rootcell, ':'); + if (!cp) { + printk(KERN_ERR "kAFS: no VL server IP addresses specified\n"); + _leave(" = %d (no colon)", -EINVAL); + return -EINVAL; + } + + /* allocate a cell record for the root cell */ + *cp++ = 0; + ret = afs_cell_create(rootcell, cp, &new_root); + if (ret < 0) { + _leave(" = %d", ret); + return ret; + } + + /* as afs_put_cell() takes locks by itself, we have to do + * a little gymnastics to be race-free. + */ + afs_get_cell(new_root); + + write_lock(&afs_cells_lock); + while (afs_cell_root) { + old_root = afs_cell_root; + afs_cell_root = NULL; + write_unlock(&afs_cells_lock); + afs_put_cell(old_root); + write_lock(&afs_cells_lock); + } + afs_cell_root = new_root; + write_unlock(&afs_cells_lock); + + _leave(" = %d", ret); + return ret; + +} /* end afs_cell_init() */ + +/*****************************************************************************/ +/* + * lookup a cell record + */ +int afs_cell_lookup(const char *name, unsigned namesz, struct afs_cell **_cell) +{ + struct afs_cell *cell; + int ret; + + _enter("\"%*.*s\",", namesz, namesz, name ? name : ""); + + *_cell = NULL; + + if (name) { + /* if the cell was named, look for it in the cell record list */ + ret = -ENOENT; + cell = NULL; + read_lock(&afs_cells_lock); + + list_for_each_entry(cell, &afs_cells, link) { + if (strncmp(cell->name, name, namesz) == 0) { + afs_get_cell(cell); + goto found; + } + } + cell = NULL; + found: + + read_unlock(&afs_cells_lock); + + if (cell) + ret = 0; + } + else { + read_lock(&afs_cells_lock); + + cell = afs_cell_root; + if (!cell) { + /* this should not happen unless user tries to mount + * when root cell is not set. Return an impossibly + * bizzare errno to alert the user. Things like + * ENOENT might be "more appropriate" but they happen + * for other reasons. + */ + ret = -EDESTADDRREQ; + } + else { + afs_get_cell(cell); + ret = 0; + } + + read_unlock(&afs_cells_lock); + } + + *_cell = cell; + _leave(" = %d (%p)", ret, cell); + return ret; + +} /* end afs_cell_lookup() */ + +/*****************************************************************************/ +/* + * try and get a cell record + */ +struct afs_cell *afs_get_cell_maybe(struct afs_cell **_cell) +{ + struct afs_cell *cell; + + write_lock(&afs_cells_lock); + + cell = *_cell; + if (cell && !list_empty(&cell->link)) + afs_get_cell(cell); + else + cell = NULL; + + write_unlock(&afs_cells_lock); + + return cell; +} /* end afs_get_cell_maybe() */ + +/*****************************************************************************/ +/* + * destroy a cell record + */ +void afs_put_cell(struct afs_cell *cell) +{ + if (!cell) + return; + + _enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name); + + /* sanity check */ + BUG_ON(atomic_read(&cell->usage) <= 0); + + /* to prevent a race, the decrement and the dequeue must be effectively + * atomic */ + write_lock(&afs_cells_lock); + + if (likely(!atomic_dec_and_test(&cell->usage))) { + write_unlock(&afs_cells_lock); + _leave(""); + return; + } + + write_unlock(&afs_cells_lock); + + BUG_ON(!list_empty(&cell->sv_list)); + BUG_ON(!list_empty(&cell->sv_graveyard)); + BUG_ON(!list_empty(&cell->vl_list)); + BUG_ON(!list_empty(&cell->vl_graveyard)); + + _leave(" [unused]"); +} /* end afs_put_cell() */ + +/*****************************************************************************/ +/* + * destroy a cell record + */ +static void afs_cell_destroy(struct afs_cell *cell) +{ + _enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name); + + /* to prevent a race, the decrement and the dequeue must be effectively + * atomic */ + write_lock(&afs_cells_lock); + + /* sanity check */ + BUG_ON(atomic_read(&cell->usage) != 0); + + list_del_init(&cell->link); + + write_unlock(&afs_cells_lock); + + down_write(&afs_cells_sem); + + afs_proc_cell_remove(cell); + + down_write(&afs_proc_cells_sem); + list_del_init(&cell->proc_link); + up_write(&afs_proc_cells_sem); + +#ifdef AFS_CACHING_SUPPORT + cachefs_relinquish_cookie(cell->cache, 0); +#endif + + up_write(&afs_cells_sem); + + BUG_ON(!list_empty(&cell->sv_list)); + BUG_ON(!list_empty(&cell->sv_graveyard)); + BUG_ON(!list_empty(&cell->vl_list)); + BUG_ON(!list_empty(&cell->vl_graveyard)); + + /* finish cleaning up the cell */ + kfree(cell); + + _leave(" [destroyed]"); +} /* end afs_cell_destroy() */ + +/*****************************************************************************/ +/* + * lookup the server record corresponding to an Rx RPC peer + */ +int afs_server_find_by_peer(const struct rxrpc_peer *peer, + struct afs_server **_server) +{ + struct afs_server *server; + struct afs_cell *cell; + + _enter("%p{a=%08x},", peer, ntohl(peer->addr.s_addr)); + + /* search the cell list */ + read_lock(&afs_cells_lock); + + list_for_each_entry(cell, &afs_cells, link) { + + _debug("? cell %s",cell->name); + + write_lock(&cell->sv_lock); + + /* check the active list */ + list_for_each_entry(server, &cell->sv_list, link) { + _debug("?? server %08x", ntohl(server->addr.s_addr)); + + if (memcmp(&server->addr, &peer->addr, + sizeof(struct in_addr)) == 0) + goto found_server; + } + + /* check the inactive list */ + spin_lock(&cell->sv_gylock); + list_for_each_entry(server, &cell->sv_graveyard, link) { + _debug("?? dead server %08x", + ntohl(server->addr.s_addr)); + + if (memcmp(&server->addr, &peer->addr, + sizeof(struct in_addr)) == 0) + goto found_dead_server; + } + spin_unlock(&cell->sv_gylock); + + write_unlock(&cell->sv_lock); + } + read_unlock(&afs_cells_lock); + + _leave(" = -ENOENT"); + return -ENOENT; + + /* we found it in the graveyard - resurrect it */ + found_dead_server: + list_del(&server->link); + list_add_tail(&server->link, &cell->sv_list); + afs_get_server(server); + afs_kafstimod_del_timer(&server->timeout); + spin_unlock(&cell->sv_gylock); + goto success; + + /* we found it - increment its ref count and return it */ + found_server: + afs_get_server(server); + + success: + write_unlock(&cell->sv_lock); + read_unlock(&afs_cells_lock); + + *_server = server; + _leave(" = 0 (s=%p c=%p)", server, cell); + return 0; + +} /* end afs_server_find_by_peer() */ + +/*****************************************************************************/ +/* + * purge in-memory cell database on module unload or afs_init() failure + * - the timeout daemon is stopped before calling this + */ +void afs_cell_purge(void) +{ + struct afs_vlocation *vlocation; + struct afs_cell *cell; + + _enter(""); + + afs_put_cell(afs_cell_root); + + while (!list_empty(&afs_cells)) { + cell = NULL; + + /* remove the next cell from the front of the list */ + write_lock(&afs_cells_lock); + + if (!list_empty(&afs_cells)) { + cell = list_entry(afs_cells.next, + struct afs_cell, link); + list_del_init(&cell->link); + } + + write_unlock(&afs_cells_lock); + + if (cell) { + _debug("PURGING CELL %s (%d)", + cell->name, atomic_read(&cell->usage)); + + BUG_ON(!list_empty(&cell->sv_list)); + BUG_ON(!list_empty(&cell->vl_list)); + + /* purge the cell's VL graveyard list */ + _debug(" - clearing VL graveyard"); + + spin_lock(&cell->vl_gylock); + + while (!list_empty(&cell->vl_graveyard)) { + vlocation = list_entry(cell->vl_graveyard.next, + struct afs_vlocation, + link); + list_del_init(&vlocation->link); + + afs_kafstimod_del_timer(&vlocation->timeout); + + spin_unlock(&cell->vl_gylock); + + afs_vlocation_do_timeout(vlocation); + /* TODO: race if move to use krxtimod instead + * of kafstimod */ + + spin_lock(&cell->vl_gylock); + } + + spin_unlock(&cell->vl_gylock); + + /* purge the cell's server graveyard list */ + _debug(" - clearing server graveyard"); + + spin_lock(&cell->sv_gylock); + + while (!list_empty(&cell->sv_graveyard)) { + struct afs_server *server; + + server = list_entry(cell->sv_graveyard.next, + struct afs_server, link); + list_del_init(&server->link); + + afs_kafstimod_del_timer(&server->timeout); + + spin_unlock(&cell->sv_gylock); + + afs_server_do_timeout(server); + + spin_lock(&cell->sv_gylock); + } + + spin_unlock(&cell->sv_gylock); + + /* now the cell should be left with no references */ + afs_cell_destroy(cell); + } + } + + _leave(""); +} /* end afs_cell_purge() */ + +/*****************************************************************************/ +/* + * match a cell record obtained from the cache + */ +#ifdef AFS_CACHING_SUPPORT +static cachefs_match_val_t afs_cell_cache_match(void *target, + const void *entry) +{ + const struct afs_cache_cell *ccell = entry; + struct afs_cell *cell = target; + + _enter("{%s},{%s}", ccell->name, cell->name); + + if (strncmp(ccell->name, cell->name, sizeof(ccell->name)) == 0) { + _leave(" = SUCCESS"); + return CACHEFS_MATCH_SUCCESS; + } + + _leave(" = FAILED"); + return CACHEFS_MATCH_FAILED; +} /* end afs_cell_cache_match() */ +#endif + +/*****************************************************************************/ +/* + * update a cell record in the cache + */ +#ifdef AFS_CACHING_SUPPORT +static void afs_cell_cache_update(void *source, void *entry) +{ + struct afs_cache_cell *ccell = entry; + struct afs_cell *cell = source; + + _enter("%p,%p", source, entry); + + strncpy(ccell->name, cell->name, sizeof(ccell->name)); + + memcpy(ccell->vl_servers, + cell->vl_addrs, + min(sizeof(ccell->vl_servers), sizeof(cell->vl_addrs))); + +} /* end afs_cell_cache_update() */ +#endif |