[mirror_ubuntu-zesty-kernel.git] / fs / afs / volume.c

/* 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
Commit	Line	Data
1da177e4 LT	1	/* volume.c: AFS volume management
	2	*
	3	* Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
	4	* Written by David Howells (dhowells@redhat.com)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11
	12	#include <linux/kernel.h>
	13	#include <linux/module.h>
	14	#include <linux/init.h>
	15	#include <linux/slab.h>
	16	#include <linux/fs.h>
	17	#include <linux/pagemap.h>
	18	#include "volume.h"
	19	#include "vnode.h"
	20	#include "cell.h"
	21	#include "cache.h"
	22	#include "cmservice.h"
	23	#include "fsclient.h"
	24	#include "vlclient.h"
	25	#include "internal.h"
	26
	27	#ifdef __KDEBUG
	28	static const char *afs_voltypes[] = { "R/W", "R/O", "BAK" };
	29	#endif
	30
	31	#ifdef AFS_CACHING_SUPPORT
	32	static cachefs_match_val_t afs_volume_cache_match(void *target,
	33	const void *entry);
	34	static void afs_volume_cache_update(void source, void entry);
	35
	36	struct cachefs_index_def afs_volume_cache_index_def = {
	37	.name = "volume",
	38	.data_size = sizeof(struct afs_cache_vhash),
	39	.keys[0] = { CACHEFS_INDEX_KEYS_BIN, 1 },
	40	.keys[1] = { CACHEFS_INDEX_KEYS_BIN, 1 },
	41	.match = afs_volume_cache_match,
	42	.update = afs_volume_cache_update,
	43	};
	44	#endif
	45
	46	/*****************************************************************************/
	47	/*
	48	* lookup a volume by name
	49	* - this can be one of the following:
	50	* "%[cell:]volume[.]" R/W volume
	51	* "#[cell:]volume[.]" R/O or R/W volume (rwparent=0),
	52	* or R/W (rwparent=1) volume
	53	* "%[cell:]volume.readonly" R/O volume
	54	* "#[cell:]volume.readonly" R/O volume
	55	* "%[cell:]volume.backup" Backup volume
	56	* "#[cell:]volume.backup" Backup volume
	57	*
	58	* The cell name is optional, and defaults to the current cell.
	59	*
	60	* See "The Rules of Mount Point Traversal" in Chapter 5 of the AFS SysAdmin
	61	* Guide
	62	* - Rule 1: Explicit type suffix forces access of that type or nothing
	63	* (no suffix, then use Rule 2 & 3)
	64	* - Rule 2: If parent volume is R/O, then mount R/O volume by preference, R/W
65	* if not available
66	* - Rule 3: If parent volume is R/W, then only mount R/W volume unless
67	* explicitly told otherwise
68	*/
69	int afs_volume_lookup(const char name, struct afs_cell cell, int rwpath,
70	struct afs_volume **_volume)
71	{
72	struct afs_vlocation *vlocation = NULL;
73	struct afs_volume *volume = NULL;
74	afs_voltype_t type;
75	const char cellname, volname, *suffix;
76	char srvtmask;
77	int force, ret, loop, cellnamesz, volnamesz;
78
79	_enter("%s,,%d,", name, rwpath);
80
81	if (!name \|\| (name[0] != '%' && name[0] != '#') \|\| !name[1]) {
82	printk("kAFS: unparsable volume name\n");
83	return -EINVAL;
84	}
85
86	/* determine the type of volume we're looking for */
87	force = 0;
88	type = AFSVL_ROVOL;
89
90	if (rwpath \|\| name[0] == '%') {
91	type = AFSVL_RWVOL;
92	force = 1;
93	}
94
95	suffix = strrchr(name, '.');
96	if (suffix) {
97	if (strcmp(suffix, ".readonly") == 0) {
98	type = AFSVL_ROVOL;
99	force = 1;
100	}
101	else if (strcmp(suffix, ".backup") == 0) {
102	type = AFSVL_BACKVOL;
103	force = 1;
104	}
105	else if (suffix[1] == 0) {
106	}
107	else {
108	suffix = NULL;
109	}
110	}
111
112	/* split the cell and volume names */
113	name++;
114	volname = strchr(name, ':');
115	if (volname) {
116	cellname = name;
117	cellnamesz = volname - name;
118	volname++;
119	}
120	else {
121	volname = name;
122	cellname = NULL;
123	cellnamesz = 0;
124	}
125
126	volnamesz = suffix ? suffix - volname : strlen(volname);
127
128	_debug("CELL:%.s [%p] VOLUME:%.s SUFFIX:%s TYPE:%d%s",
129	cellnamesz, cellnamesz, cellname ?: "", cell,
130	volnamesz, volnamesz, volname, suffix ?: "-",
131	type,
132	force ? " FORCE" : "");
133
134	/* lookup the cell record */
135	if (cellname \|\| !cell) {
136	ret = afs_cell_lookup(cellname, cellnamesz, &cell);
137	if (ret<0) {
138	printk("kAFS: unable to lookup cell '%s'\n",
139	cellname ?: "");
140	goto error;
141	}
142	}
143	else {
144	afs_get_cell(cell);
145	}
146
147	/* lookup the volume location record */
148	ret = afs_vlocation_lookup(cell, volname, volnamesz, &vlocation);
149	if (ret < 0)
150	goto error;
151
152	/* make the final decision on the type we want */
153	ret = -ENOMEDIUM;
154	if (force && !(vlocation->vldb.vidmask & (1 << type)))
155	goto error;
156
157	srvtmask = 0;
158	for (loop = 0; loop < vlocation->vldb.nservers; loop++)
159	srvtmask \|= vlocation->vldb.srvtmask[loop];
160
161	if (force) {
162	if (!(srvtmask & (1 << type)))
163	goto error;
164	}
165	else if (srvtmask & AFS_VOL_VTM_RO) {
166	type = AFSVL_ROVOL;
167	}
168	else if (srvtmask & AFS_VOL_VTM_RW) {
169	type = AFSVL_RWVOL;
170	}
171	else {
172	goto error;
173	}
174
175	down_write(&cell->vl_sem);
176
177	/* is the volume already active? */
178	if (vlocation->vols[type]) {
179	/* yes - re-use it */
180	volume = vlocation->vols[type];
181	afs_get_volume(volume);
182	goto success;
183	}
184
185	/* create a new volume record */
186	_debug("creating new volume record");
187
188	ret = -ENOMEM;
f8314dc6	189	volume = kzalloc(sizeof(struct afs_volume), GFP_KERNEL);
1da177e4 LT	190	if (!volume)
	191	goto error_up;
	192
1da177e4 LT	193	atomic_set(&volume->usage, 1);
	194	volume->type = type;
	195	volume->type_force = force;
	196	volume->cell = cell;
	197	volume->vid = vlocation->vldb.vid[type];
	198
	199	init_rwsem(&volume->server_sem);
	200
	201	/* look up all the applicable server records */
	202	for (loop = 0; loop < 8; loop++) {
	203	if (vlocation->vldb.srvtmask[loop] & (1 << volume->type)) {
	204	ret = afs_server_lookup(
	205	volume->cell,
	206	&vlocation->vldb.servers[loop],
	207	&volume->servers[volume->nservers]);
	208	if (ret < 0)
	209	goto error_discard;
	210
	211	volume->nservers++;
	212	}
	213	}
	214
	215	/* attach the cache and volume location */
	216	#ifdef AFS_CACHING_SUPPORT
	217	cachefs_acquire_cookie(vlocation->cache,
	218	&afs_vnode_cache_index_def,
	219	volume,
	220	&volume->cache);
	221	#endif
	222
	223	afs_get_vlocation(vlocation);
	224	volume->vlocation = vlocation;
	225
	226	vlocation->vols[type] = volume;
	227
	228	success:
	229	_debug("kAFS selected %s volume %08x",
	230	afs_voltypes[volume->type], volume->vid);
	231	*_volume = volume;
	232	ret = 0;
	233
	234	/* clean up */
	235	error_up:
	236	up_write(&cell->vl_sem);
	237	error:
	238	afs_put_vlocation(vlocation);
	239	afs_put_cell(cell);
	240
	241	_leave(" = %d (%p)", ret, volume);
	242	return ret;
	243
	244	error_discard:
	245	up_write(&cell->vl_sem);
	246
	247	for (loop = volume->nservers - 1; loop >= 0; loop--)
	248	afs_put_server(volume->servers[loop]);
	249
	250	kfree(volume);
	251	goto error;
	252	} /* end afs_volume_lookup() */
	253
	254	/*****************************************************************************/
	255	/*
	256	* destroy a volume record
257	*/
258	void afs_put_volume(struct afs_volume *volume)
259	{
260	struct afs_vlocation *vlocation;
261	int loop;
262
263	if (!volume)
264	return;
265
266	_enter("%p", volume);
267
268	vlocation = volume->vlocation;
269
270	/* sanity check */
271	BUG_ON(atomic_read(&volume->usage) <= 0);
272
273	/* to prevent a race, the decrement and the dequeue must be effectively
274	* atomic */
275	down_write(&vlocation->cell->vl_sem);
276
277	if (likely(!atomic_dec_and_test(&volume->usage))) {
278	up_write(&vlocation->cell->vl_sem);
279	_leave("");
280	return;
281	}
282
283	vlocation->vols[volume->type] = NULL;
284
285	up_write(&vlocation->cell->vl_sem);
286
287	/* finish cleaning up the volume */
288	#ifdef AFS_CACHING_SUPPORT
289	cachefs_relinquish_cookie(volume->cache, 0);
290	#endif
291	afs_put_vlocation(vlocation);
292
293	for (loop = volume->nservers - 1; loop >= 0; loop--)
294	afs_put_server(volume->servers[loop]);
295
296	kfree(volume);
297
298	_leave(" [destroyed]");
299	} /* end afs_put_volume() */
300
301	/*****************************************************************************/
302	/*
303	* pick a server to use to try accessing this volume
304	* - returns with an elevated usage count on the server chosen
305	*/
306	int afs_volume_pick_fileserver(struct afs_volume *volume,
307	struct afs_server **_server)
308	{
309	struct afs_server *server;
310	int ret, state, loop;
311
312	_enter("%s", volume->vlocation->vldb.name);
313
314	down_read(&volume->server_sem);
315
316	/* handle the no-server case */
317	if (volume->nservers == 0) {
318	ret = volume->rjservers ? -ENOMEDIUM : -ESTALE;
319	up_read(&volume->server_sem);
320	_leave(" = %d [no servers]", ret);
321	return ret;
322	}
323
324	/* basically, just search the list for the first live server and use
325	* that */
326	ret = 0;
327	for (loop = 0; loop < volume->nservers; loop++) {
328	server = volume->servers[loop];
329	state = server->fs_state;
330
331	switch (state) {
332	/* found an apparently healthy server */
333	case 0:
334	afs_get_server(server);
335	up_read(&volume->server_sem);
336	*_server = server;
337	_leave(" = 0 (picked %08x)",
338	ntohl(server->addr.s_addr));
339	return 0;
340
341	case -ENETUNREACH:
342	if (ret == 0)
343	ret = state;
344	break;
345
346	case -EHOSTUNREACH:
347	if (ret == 0 \|\|
348	ret == -ENETUNREACH)
349	ret = state;
350	break;
351
352	case -ECONNREFUSED:
353	if (ret == 0 \|\|
354	ret == -ENETUNREACH \|\|
355	ret == -EHOSTUNREACH)
356	ret = state;
357	break;
358
359	default:
360	case -EREMOTEIO:
361	if (ret == 0 \|\|
362	ret == -ENETUNREACH \|\|
363	ret == -EHOSTUNREACH \|\|
364	ret == -ECONNREFUSED)
365	ret = state;
366	break;
367	}
368	}
369
370	/* no available servers
371	* - TODO: handle the no active servers case better
372	*/
373	up_read(&volume->server_sem);
374	_leave(" = %d", ret);
375	return ret;
376	} /* end afs_volume_pick_fileserver() */
377
378	/*****************************************************************************/
379	/*
380	* release a server after use
381	* - releases the ref on the server struct that was acquired by picking
382	* - records result of using a particular server to access a volume
383	* - return 0 to try again, 1 if okay or to issue error
384	*/
385	int afs_volume_release_fileserver(struct afs_volume *volume,
386	struct afs_server *server,
387	int result)
388	{
389	unsigned loop;
390
391	_enter("%s,%08x,%d",
392	volume->vlocation->vldb.name, ntohl(server->addr.s_addr),
393	result);
394
395	switch (result) {
396	/* success */
397	case 0:
398	server->fs_act_jif = jiffies;
399	break;
400
401	/* the fileserver denied all knowledge of the volume */
402	case -ENOMEDIUM:
403	server->fs_act_jif = jiffies;
404	down_write(&volume->server_sem);
405
406	/* first, find where the server is in the active list (if it
407	* is) */
408	for (loop = 0; loop < volume->nservers; loop++)
409	if (volume->servers[loop] == server)
410	goto present;
411
412	/* no longer there - may have been discarded by another op */
413	goto try_next_server_upw;
414
415	present:
416	volume->nservers--;
417	memmove(&volume->servers[loop],
418	&volume->servers[loop + 1],
419	sizeof(volume->servers[loop]) *
420	(volume->nservers - loop));
421	volume->servers[volume->nservers] = NULL;
422	afs_put_server(server);
423	volume->rjservers++;
424
425	if (volume->nservers > 0)
426	/* another server might acknowledge its existence */
427	goto try_next_server_upw;
428
429	/* handle the case where all the fileservers have rejected the
430	* volume
431	* - TODO: try asking the fileservers for volume information
432	* - TODO: contact the VL server again to see if the volume is
433	* no longer registered
434	*/
435	up_write(&volume->server_sem);
436	afs_put_server(server);
437	_leave(" [completely rejected]");
438	return 1;
439
440	/* problem reaching the server */
441	case -ENETUNREACH:
442	case -EHOSTUNREACH:
443	case -ECONNREFUSED:
444	case -ETIMEDOUT:
445	case -EREMOTEIO:
446	/* mark the server as dead
447	* TODO: vary dead timeout depending on error
448	*/
449	spin_lock(&server->fs_lock);
450	if (!server->fs_state) {
451	server->fs_dead_jif = jiffies + HZ * 10;
452	server->fs_state = result;
453	printk("kAFS: SERVER DEAD state=%d\n", result);
454	}
455	spin_unlock(&server->fs_lock);
456	goto try_next_server;
457
458	/* miscellaneous error */
459	default:
460	server->fs_act_jif = jiffies;
461	case -ENOMEM:
462	case -ENONET:
463	break;
464	}
465
466	/* tell the caller to accept the result */
467	afs_put_server(server);
468	_leave("");
469	return 1;
470
471	/* tell the caller to loop around and try the next server */
472	try_next_server_upw:
473	up_write(&volume->server_sem);
474	try_next_server:
475	afs_put_server(server);
476	_leave(" [try next server]");
477	return 0;
478
479	} /* end afs_volume_release_fileserver() */
480
481	/*****************************************************************************/
482	/*
483	* match a volume hash record stored in the cache
484	*/
485	#ifdef AFS_CACHING_SUPPORT
486	static cachefs_match_val_t afs_volume_cache_match(void *target,
487	const void *entry)
488	{
489	const struct afs_cache_vhash *vhash = entry;
490	struct afs_volume *volume = target;
491
492	_enter("{%u},{%u}", volume->type, vhash->vtype);
493
494	if (volume->type == vhash->vtype) {
495	_leave(" = SUCCESS");
496	return CACHEFS_MATCH_SUCCESS;
497	}
498
499	_leave(" = FAILED");
500	return CACHEFS_MATCH_FAILED;
501	} /* end afs_volume_cache_match() */
502	#endif
503
504	/*****************************************************************************/
505	/*
506	* update a volume hash record stored in the cache
507	*/
508	#ifdef AFS_CACHING_SUPPORT
509	static void afs_volume_cache_update(void source, void entry)
510	{
511	struct afs_cache_vhash *vhash = entry;
512	struct afs_volume *volume = source;
513
514	_enter("");
515
516	vhash->vtype = volume->type;
517
518	} /* end afs_volume_cache_update() */
519	#endif