1 files changed, 569 insertions, 0 deletions

diff --git a/fs/afs/cell.c b/fs/afs/cell.c
new file mode 100644
index 000000000000..009a9ae88d61
--- /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