/* 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 = kzalloc(sizeof(struct afs_volume), GFP_KERNEL);
if (!volume)
goto error_up;
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
