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