1 files changed, 520 insertions, 0 deletions

diff --git a/fs/afs/volume.c b/fs/afs/volume.c
new file mode 100644
index 000000000000..0ff4b86476e3
--- /dev/null
+++ b/fs/afs/volume.c
@@ -0,0 +1,520 @@
+/* volume.c: AFS volume 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 "vnode.h"
+#include "cell.h"
+#include "cache.h"
+#include "cmservice.h"
+#include "fsclient.h"
+#include "vlclient.h"
+#include "internal.h"
+
+#ifdef __KDEBUG
+static const char *afs_voltypes[] = { "R/W", "R/O", "BAK" };
+#endif
+
+#ifdef AFS_CACHING_SUPPORT
+static cachefs_match_val_t afs_volume_cache_match(void *target,
+                                                  const void *entry);
+static void afs_volume_cache_update(void *source, void *entry);
+
+struct cachefs_index_def afs_volume_cache_index_def = {
+        .name           = "volume",
+        .data_size      = sizeof(struct afs_cache_vhash),
+        .keys[0]        = { CACHEFS_INDEX_KEYS_BIN, 1 },
+        .keys[1]        = { CACHEFS_INDEX_KEYS_BIN, 1 },
+        .match          = afs_volume_cache_match,
+        .update         = afs_volume_cache_update,
+};
+#endif
+
+/*****************************************************************************/
+/*
+ * lookup a volume by name
+ * - this can be one of the following:
+ *      "%[cell:]volume[.]"             R/W volume
+ *      "#[cell:]volume[.]"             R/O or R/W volume (rwparent=0),
+ *                                       or R/W (rwparent=1) volume
+ *      "%[cell:]volume.readonly"       R/O volume
+ *      "#[cell:]volume.readonly"       R/O volume
+ *      "%[cell:]volume.backup"         Backup volume
+ *      "#[cell:]volume.backup"         Backup volume
+ *
+ * The cell name is optional, and defaults to the current cell.
+ *
+ * See "The Rules of Mount Point Traversal" in Chapter 5 of the AFS SysAdmin
+ * Guide
+ * - Rule 1: Explicit type suffix forces access of that type or nothing
+ *           (no suffix, then use Rule 2 & 3)
+ * - Rule 2: If parent volume is R/O, then mount R/O volume by preference, R/W
+ *           if not available
+ * - Rule 3: If parent volume is R/W, then only mount R/W volume unless
+ *           explicitly told otherwise
+ */
+int afs_volume_lookup(const char *name, struct afs_cell *cell, int rwpath,
+                      struct afs_volume **_volume)
+{
+        struct afs_vlocation *vlocation = NULL;
+        struct afs_volume *volume = NULL;
+        afs_voltype_t type;
+        const char *cellname, *volname, *suffix;
+        char srvtmask;
+        int force, ret, loop, cellnamesz, volnamesz;
+
+        _enter("%s,,%d,", name, rwpath);
+
+        if (!name || (name[0] != '%' && name[0] != '#') || !name[1]) {
+                printk("kAFS: unparsable volume name\n");
+                return -EINVAL;
+        }
+
+        /* determine the type of volume we're looking for */
+        force = 0;
+        type = AFSVL_ROVOL;
+
+        if (rwpath || name[0] == '%') {
+                type = AFSVL_RWVOL;
+                force = 1;
+        }
+
+        suffix = strrchr(name, '.');
+        if (suffix) {
+                if (strcmp(suffix, ".readonly") == 0) {
+                        type = AFSVL_ROVOL;
+                        force = 1;
+                }
+                else if (strcmp(suffix, ".backup") == 0) {
+                        type = AFSVL_BACKVOL;
+                        force = 1;
+                }
+                else if (suffix[1] == 0) {
+                }
+                else {
+                        suffix = NULL;
+                }
+        }
+
+        /* split the cell and volume names */
+        name++;
+        volname = strchr(name, ':');
+        if (volname) {
+                cellname = name;
+                cellnamesz = volname - name;
+                volname++;
+        }
+        else {
+                volname = name;
+                cellname = NULL;
+                cellnamesz = 0;
+        }
+
+        volnamesz = suffix ? suffix - volname : strlen(volname);
+
+        _debug("CELL:%*.*s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
+               cellnamesz, cellnamesz, cellname ?: "", cell,
+               volnamesz, volnamesz, volname, suffix ?: "-",
+               type,
+               force ? " FORCE" : "");
+
+        /* lookup the cell record */
+        if (cellname || !cell) {
+                ret = afs_cell_lookup(cellname, cellnamesz, &cell);
+                if (ret<0) {
+                        printk("kAFS: unable to lookup cell '%s'\n",
+                               cellname ?: "");
+                        goto error;
+                }
+        }
+        else {
+                afs_get_cell(cell);
+        }
+
+        /* lookup the volume location record */
+        ret = afs_vlocation_lookup(cell, volname, volnamesz, &vlocation);
+        if (ret < 0)
+                goto error;
+
+        /* make the final decision on the type we want */
+        ret = -ENOMEDIUM;
+        if (force && !(vlocation->vldb.vidmask & (1 << type)))
+                goto error;
+
+        srvtmask = 0;
+        for (loop = 0; loop < vlocation->vldb.nservers; loop++)
+                srvtmask |= vlocation->vldb.srvtmask[loop];
+
+        if (force) {
+                if (!(srvtmask & (1 << type)))
+                        goto error;
+        }
+        else if (srvtmask & AFS_VOL_VTM_RO) {
+                type = AFSVL_ROVOL;
+        }
+        else if (srvtmask & AFS_VOL_VTM_RW) {
+                type = AFSVL_RWVOL;
+        }
+        else {
+                goto error;
+        }
+
+        down_write(&cell->vl_sem);
+
+        /* is the volume already active? */
+        if (vlocation->vols[type]) {
+                /* yes - re-use it */
+                volume = vlocation->vols[type];
+                afs_get_volume(volume);
+                goto success;
+        }
+
+        /* create a new volume record */
+        _debug("creating new volume record");
+
+        ret = -ENOMEM;
+        volume = kmalloc(sizeof(struct afs_volume), GFP_KERNEL);
+        if (!volume)
+                goto error_up;
+
+        memset(volume, 0, sizeof(struct afs_volume));
+        atomic_set(&volume->usage, 1);
+        volume->type            = type;
+        volume->type_force      = force;
+        volume->cell            = cell;
+        volume->vid             = vlocation->vldb.vid[type];
+
+        init_rwsem(&volume->server_sem);
+
+        /* look up all the applicable server records */
+        for (loop = 0; loop < 8; loop++) {
+                if (vlocation->vldb.srvtmask[loop] & (1 << volume->type)) {
+                        ret = afs_server_lookup(
+                                volume->cell,
+                                &vlocation->vldb.servers[loop],
+                                &volume->servers[volume->nservers]);
+                        if (ret < 0)
+                                goto error_discard;
+
+                        volume->nservers++;
+                }
+        }
+
+        /* attach the cache and volume location */
+#ifdef AFS_CACHING_SUPPORT
+        cachefs_acquire_cookie(vlocation->cache,
+                               &afs_vnode_cache_index_def,
+                               volume,
+                               &volume->cache);
+#endif
+
+        afs_get_vlocation(vlocation);
+        volume->vlocation = vlocation;
+
+        vlocation->vols[type] = volume;
+
+ success:
+        _debug("kAFS selected %s volume %08x",
+               afs_voltypes[volume->type], volume->vid);
+        *_volume = volume;
+        ret = 0;
+
+        /* clean up */
+ error_up:
+        up_write(&cell->vl_sem);
+ error:
+        afs_put_vlocation(vlocation);
+        afs_put_cell(cell);
+
+        _leave(" = %d (%p)", ret, volume);
+        return ret;
+
+ error_discard:
+        up_write(&cell->vl_sem);
+
+        for (loop = volume->nservers - 1; loop >= 0; loop--)
+                afs_put_server(volume->servers[loop]);
+
+        kfree(volume);
+        goto error;
+} /* end afs_volume_lookup() */
+
+/*****************************************************************************/
+/*
+ * destroy a volume record
+ */
+void afs_put_volume(struct afs_volume *volume)
+{
+        struct afs_vlocation *vlocation;
+        int loop;
+
+        if (!volume)
+                return;
+
+        _enter("%p", volume);
+
+        vlocation = volume->vlocation;
+
+        /* sanity check */
+        BUG_ON(atomic_read(&volume->usage) <= 0);
+
+        /* to prevent a race, the decrement and the dequeue must be effectively
+         * atomic */
+        down_write(&vlocation->cell->vl_sem);
+
+        if (likely(!atomic_dec_and_test(&volume->usage))) {
+                up_write(&vlocation->cell->vl_sem);
+                _leave("");
+                return;
+        }
+
+        vlocation->vols[volume->type] = NULL;
+
+        up_write(&vlocation->cell->vl_sem);
+
+        /* finish cleaning up the volume */
+#ifdef AFS_CACHING_SUPPORT
+        cachefs_relinquish_cookie(volume->cache, 0);
+#endif
+        afs_put_vlocation(vlocation);
+
+        for (loop = volume->nservers - 1; loop >= 0; loop--)
+                afs_put_server(volume->servers[loop]);
+
+        kfree(volume);
+
+        _leave(" [destroyed]");
+} /* end afs_put_volume() */
+
+/*****************************************************************************/
+/*
+ * pick a server to use to try accessing this volume
+ * - returns with an elevated usage count on the server chosen
+ */
+int afs_volume_pick_fileserver(struct afs_volume *volume,
+                               struct afs_server **_server)
+{
+        struct afs_server *server;
+        int ret, state, loop;
+
+        _enter("%s", volume->vlocation->vldb.name);
+
+        down_read(&volume->server_sem);
+
+        /* handle the no-server case */
+        if (volume->nservers == 0) {
+                ret = volume->rjservers ? -ENOMEDIUM : -ESTALE;
+                up_read(&volume->server_sem);
+                _leave(" = %d [no servers]", ret);
+                return ret;
+        }
+
+        /* basically, just search the list for the first live server and use
+         * that */
+        ret = 0;
+        for (loop = 0; loop < volume->nservers; loop++) {
+                server = volume->servers[loop];
+                state = server->fs_state;
+
+                switch (state) {
+                        /* found an apparently healthy server */
+                case 0:
+                        afs_get_server(server);
+                        up_read(&volume->server_sem);
+                        *_server = server;
+                        _leave(" = 0 (picked %08x)",
+                               ntohl(server->addr.s_addr));
+                        return 0;
+
+                case -ENETUNREACH:
+                        if (ret == 0)
+                                ret = state;
+                        break;
+
+                case -EHOSTUNREACH:
+                        if (ret == 0 ||
+                            ret == -ENETUNREACH)
+                                ret = state;
+                        break;
+
+                case -ECONNREFUSED:
+                        if (ret == 0 ||
+                            ret == -ENETUNREACH ||
+                            ret == -EHOSTUNREACH)
+                                ret = state;
+                        break;
+
+                default:
+                case -EREMOTEIO:
+                        if (ret == 0 ||
+                            ret == -ENETUNREACH ||
+                            ret == -EHOSTUNREACH ||
+                            ret == -ECONNREFUSED)
+                                ret = state;
+                        break;
+                }
+        }
+
+        /* no available servers
+         * - TODO: handle the no active servers case better
+         */
+        up_read(&volume->server_sem);
+        _leave(" = %d", ret);
+        return ret;
+} /* end afs_volume_pick_fileserver() */
+
+/*****************************************************************************/
+/*
+ * release a server after use
+ * - releases the ref on the server struct that was acquired by picking
+ * - records result of using a particular server to access a volume
+ * - return 0 to try again, 1 if okay or to issue error
+ */
+int afs_volume_release_fileserver(struct afs_volume *volume,
+                                  struct afs_server *server,
+                                  int result)
+{
+        unsigned loop;
+
+        _enter("%s,%08x,%d",
+               volume->vlocation->vldb.name, ntohl(server->addr.s_addr),
+               result);
+
+        switch (result) {
+                /* success */
+        case 0:
+                server->fs_act_jif = jiffies;
+                break;
+
+                /* the fileserver denied all knowledge of the volume */
+        case -ENOMEDIUM:
+                server->fs_act_jif = jiffies;
+                down_write(&volume->server_sem);
+
+                /* first, find where the server is in the active list (if it
+                 * is) */
+                for (loop = 0; loop < volume->nservers; loop++)
+                        if (volume->servers[loop] == server)
+                                goto present;
+
+                /* no longer there - may have been discarded by another op */
+                goto try_next_server_upw;
+
+        present:
+                volume->nservers--;
+                memmove(&volume->servers[loop],
+                        &volume->servers[loop + 1],
+                        sizeof(volume->servers[loop]) *
+                        (volume->nservers - loop));
+                volume->servers[volume->nservers] = NULL;
+                afs_put_server(server);
+                volume->rjservers++;
+
+                if (volume->nservers > 0)
+                        /* another server might acknowledge its existence */
+                        goto try_next_server_upw;
+
+                /* handle the case where all the fileservers have rejected the
+                 * volume
+                 * - TODO: try asking the fileservers for volume information
+                 * - TODO: contact the VL server again to see if the volume is
+                 *         no longer registered
+                 */
+                up_write(&volume->server_sem);
+                afs_put_server(server);
+                _leave(" [completely rejected]");
+                return 1;
+
+                /* problem reaching the server */
+        case -ENETUNREACH:
+        case -EHOSTUNREACH:
+        case -ECONNREFUSED:
+        case -ETIMEDOUT:
+        case -EREMOTEIO:
+                /* mark the server as dead
+                 * TODO: vary dead timeout depending on error
+                 */
+                spin_lock(&server->fs_lock);
+                if (!server->fs_state) {
+                        server->fs_dead_jif = jiffies + HZ * 10;
+                        server->fs_state = result;
+                        printk("kAFS: SERVER DEAD state=%d\n", result);
+                }
+                spin_unlock(&server->fs_lock);
+                goto try_next_server;
+
+                /* miscellaneous error */
+        default:
+                server->fs_act_jif = jiffies;
+        case -ENOMEM:
+        case -ENONET:
+                break;
+        }
+
+        /* tell the caller to accept the result */
+        afs_put_server(server);
+        _leave("");
+        return 1;
+
+        /* tell the caller to loop around and try the next server */
+ try_next_server_upw:
+        up_write(&volume->server_sem);
+ try_next_server:
+        afs_put_server(server);
+        _leave(" [try next server]");
+        return 0;
+
+} /* end afs_volume_release_fileserver() */
+
+/*****************************************************************************/
+/*
+ * match a volume hash record stored in the cache
+ */
+#ifdef AFS_CACHING_SUPPORT
+static cachefs_match_val_t afs_volume_cache_match(void *target,
+                                                  const void *entry)
+{
+        const struct afs_cache_vhash *vhash = entry;
+        struct afs_volume *volume = target;
+
+        _enter("{%u},{%u}", volume->type, vhash->vtype);
+
+        if (volume->type == vhash->vtype) {
+                _leave(" = SUCCESS");
+                return CACHEFS_MATCH_SUCCESS;
+        }
+
+        _leave(" = FAILED");
+        return CACHEFS_MATCH_FAILED;
+} /* end afs_volume_cache_match() */
+#endif
+
+/*****************************************************************************/
+/*
+ * update a volume hash record stored in the cache
+ */
+#ifdef AFS_CACHING_SUPPORT
+static void afs_volume_cache_update(void *source, void *entry)
+{
+        struct afs_cache_vhash *vhash = entry;
+        struct afs_volume *volume = source;
+
+        _enter("");
+
+        vhash->vtype = volume->type;
+
+} /* end afs_volume_cache_update() */
+#endif