1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* AFS volume management
4 * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
8 #include <linux/kernel.h>
9 #include <linux/slab.h>
12 unsigned __read_mostly afs_volume_gc_delay
= 10;
13 unsigned __read_mostly afs_volume_record_life
= 60 * 60;
16 * Insert a volume into a cell. If there's an existing volume record, that is
17 * returned instead with a ref held.
19 static struct afs_volume
*afs_insert_volume_into_cell(struct afs_cell
*cell
,
20 struct afs_volume
*volume
)
23 struct rb_node
*parent
= NULL
, **pp
;
25 write_seqlock(&cell
->volume_lock
);
27 pp
= &cell
->volumes
.rb_node
;
30 p
= rb_entry(parent
, struct afs_volume
, cell_node
);
31 if (p
->vid
< volume
->vid
) {
33 } else if (p
->vid
> volume
->vid
) {
34 pp
= &(*pp
)->rb_right
;
36 volume
= afs_get_volume(p
, afs_volume_trace_get_cell_insert
);
41 rb_link_node_rcu(&volume
->cell_node
, parent
, pp
);
42 rb_insert_color(&volume
->cell_node
, &cell
->volumes
);
43 hlist_add_head_rcu(&volume
->proc_link
, &cell
->proc_volumes
);
46 write_sequnlock(&cell
->volume_lock
);
51 static void afs_remove_volume_from_cell(struct afs_volume
*volume
)
53 struct afs_cell
*cell
= volume
->cell
;
55 if (!hlist_unhashed(&volume
->proc_link
)) {
56 trace_afs_volume(volume
->vid
, atomic_read(&volume
->usage
),
57 afs_volume_trace_remove
);
58 write_seqlock(&cell
->volume_lock
);
59 hlist_del_rcu(&volume
->proc_link
);
60 rb_erase(&volume
->cell_node
, &cell
->volumes
);
61 write_sequnlock(&cell
->volume_lock
);
66 * Allocate a volume record and load it up from a vldb record.
68 static struct afs_volume
*afs_alloc_volume(struct afs_fs_context
*params
,
69 struct afs_vldb_entry
*vldb
,
70 unsigned long type_mask
)
72 struct afs_server_list
*slist
;
73 struct afs_volume
*volume
;
74 int ret
= -ENOMEM
, nr_servers
= 0, i
;
76 for (i
= 0; i
< vldb
->nr_servers
; i
++)
77 if (vldb
->fs_mask
[i
] & type_mask
)
80 volume
= kzalloc(sizeof(struct afs_volume
), GFP_KERNEL
);
84 volume
->vid
= vldb
->vid
[params
->type
];
85 volume
->update_at
= ktime_get_real_seconds() + afs_volume_record_life
;
86 volume
->cell
= afs_get_cell(params
->cell
, afs_cell_trace_get_vol
);
87 volume
->type
= params
->type
;
88 volume
->type_force
= params
->force
;
89 volume
->name_len
= vldb
->name_len
;
91 atomic_set(&volume
->usage
, 1);
92 INIT_HLIST_NODE(&volume
->proc_link
);
93 rwlock_init(&volume
->servers_lock
);
94 rwlock_init(&volume
->cb_v_break_lock
);
95 memcpy(volume
->name
, vldb
->name
, vldb
->name_len
+ 1);
97 slist
= afs_alloc_server_list(params
->cell
, params
->key
, vldb
, type_mask
);
103 refcount_set(&slist
->usage
, 1);
104 rcu_assign_pointer(volume
->servers
, slist
);
105 trace_afs_volume(volume
->vid
, 1, afs_volume_trace_alloc
);
109 afs_put_cell(volume
->cell
, afs_cell_trace_put_vol
);
116 * Look up or allocate a volume record.
118 static struct afs_volume
*afs_lookup_volume(struct afs_fs_context
*params
,
119 struct afs_vldb_entry
*vldb
,
120 unsigned long type_mask
)
122 struct afs_volume
*candidate
, *volume
;
124 candidate
= afs_alloc_volume(params
, vldb
, type_mask
);
125 if (IS_ERR(candidate
))
128 volume
= afs_insert_volume_into_cell(params
->cell
, candidate
);
129 if (volume
!= candidate
)
130 afs_put_volume(params
->net
, candidate
, afs_volume_trace_put_cell_dup
);
135 * Look up a VLDB record for a volume.
137 static struct afs_vldb_entry
*afs_vl_lookup_vldb(struct afs_cell
*cell
,
142 struct afs_vldb_entry
*vldb
= ERR_PTR(-EDESTADDRREQ
);
143 struct afs_vl_cursor vc
;
146 if (!afs_begin_vlserver_operation(&vc
, cell
, key
))
147 return ERR_PTR(-ERESTARTSYS
);
149 while (afs_select_vlserver(&vc
)) {
150 vldb
= afs_vl_get_entry_by_name_u(&vc
, volname
, volnamesz
);
153 ret
= afs_end_vlserver_operation(&vc
);
154 return ret
< 0 ? ERR_PTR(ret
) : vldb
;
158 * Look up a volume in the VL server and create a candidate volume record for
161 * The volume name can be one of the following:
162 * "%[cell:]volume[.]" R/W volume
163 * "#[cell:]volume[.]" R/O or R/W volume (rwparent=0),
164 * or R/W (rwparent=1) volume
165 * "%[cell:]volume.readonly" R/O volume
166 * "#[cell:]volume.readonly" R/O volume
167 * "%[cell:]volume.backup" Backup volume
168 * "#[cell:]volume.backup" Backup volume
170 * The cell name is optional, and defaults to the current cell.
172 * See "The Rules of Mount Point Traversal" in Chapter 5 of the AFS SysAdmin
174 * - Rule 1: Explicit type suffix forces access of that type or nothing
175 * (no suffix, then use Rule 2 & 3)
176 * - Rule 2: If parent volume is R/O, then mount R/O volume by preference, R/W
178 * - Rule 3: If parent volume is R/W, then only mount R/W volume unless
179 * explicitly told otherwise
181 struct afs_volume
*afs_create_volume(struct afs_fs_context
*params
)
183 struct afs_vldb_entry
*vldb
;
184 struct afs_volume
*volume
;
185 unsigned long type_mask
= 1UL << params
->type
;
187 vldb
= afs_vl_lookup_vldb(params
->cell
, params
->key
,
188 params
->volname
, params
->volnamesz
);
190 return ERR_CAST(vldb
);
192 if (test_bit(AFS_VLDB_QUERY_ERROR
, &vldb
->flags
)) {
193 volume
= ERR_PTR(vldb
->error
);
197 /* Make the final decision on the type we want */
198 volume
= ERR_PTR(-ENOMEDIUM
);
200 if (!(vldb
->flags
& type_mask
))
202 } else if (test_bit(AFS_VLDB_HAS_RO
, &vldb
->flags
)) {
203 params
->type
= AFSVL_ROVOL
;
204 } else if (test_bit(AFS_VLDB_HAS_RW
, &vldb
->flags
)) {
205 params
->type
= AFSVL_RWVOL
;
210 type_mask
= 1UL << params
->type
;
211 volume
= afs_lookup_volume(params
, vldb
, type_mask
);
219 * Destroy a volume record
221 static void afs_destroy_volume(struct afs_net
*net
, struct afs_volume
*volume
)
223 _enter("%p", volume
);
225 #ifdef CONFIG_AFS_FSCACHE
226 ASSERTCMP(volume
->cache
, ==, NULL
);
229 afs_remove_volume_from_cell(volume
);
230 afs_put_serverlist(net
, rcu_access_pointer(volume
->servers
));
231 afs_put_cell(volume
->cell
, afs_cell_trace_put_vol
);
232 trace_afs_volume(volume
->vid
, atomic_read(&volume
->usage
),
233 afs_volume_trace_free
);
234 kfree_rcu(volume
, rcu
);
236 _leave(" [destroyed]");
240 * Get a reference on a volume record.
242 struct afs_volume
*afs_get_volume(struct afs_volume
*volume
,
243 enum afs_volume_trace reason
)
246 int u
= atomic_inc_return(&volume
->usage
);
247 trace_afs_volume(volume
->vid
, u
, reason
);
254 * Drop a reference on a volume record.
256 void afs_put_volume(struct afs_net
*net
, struct afs_volume
*volume
,
257 enum afs_volume_trace reason
)
260 afs_volid_t vid
= volume
->vid
;
261 int u
= atomic_dec_return(&volume
->usage
);
262 trace_afs_volume(vid
, u
, reason
);
264 afs_destroy_volume(net
, volume
);
271 void afs_activate_volume(struct afs_volume
*volume
)
273 #ifdef CONFIG_AFS_FSCACHE
274 volume
->cache
= fscache_acquire_cookie(volume
->cell
->cache
,
275 &afs_volume_cache_index_def
,
276 &volume
->vid
, sizeof(volume
->vid
),
283 * Deactivate a volume.
285 void afs_deactivate_volume(struct afs_volume
*volume
)
287 _enter("%s", volume
->name
);
289 #ifdef CONFIG_AFS_FSCACHE
290 fscache_relinquish_cookie(volume
->cache
, NULL
,
291 test_bit(AFS_VOLUME_DELETED
, &volume
->flags
));
292 volume
->cache
= NULL
;
299 * Query the VL service to update the volume status.
301 static int afs_update_volume_status(struct afs_volume
*volume
, struct key
*key
)
303 struct afs_server_list
*new, *old
, *discard
;
304 struct afs_vldb_entry
*vldb
;
310 /* We look up an ID by passing it as a decimal string in the
311 * operation's name parameter.
313 idsz
= sprintf(idbuf
, "%llu", volume
->vid
);
315 vldb
= afs_vl_lookup_vldb(volume
->cell
, key
, idbuf
, idsz
);
321 /* See if the volume got renamed. */
322 if (vldb
->name_len
!= volume
->name_len
||
323 memcmp(vldb
->name
, volume
->name
, vldb
->name_len
) != 0) {
324 /* TODO: Use RCU'd string. */
325 memcpy(volume
->name
, vldb
->name
, AFS_MAXVOLNAME
);
326 volume
->name_len
= vldb
->name_len
;
329 /* See if the volume's server list got updated. */
330 new = afs_alloc_server_list(volume
->cell
, key
,
331 vldb
, (1 << volume
->type
));
337 write_lock(&volume
->servers_lock
);
340 old
= rcu_dereference_protected(volume
->servers
,
341 lockdep_is_held(&volume
->servers_lock
));
342 if (afs_annotate_server_list(new, old
)) {
343 new->seq
= volume
->servers_seq
+ 1;
344 rcu_assign_pointer(volume
->servers
, new);
346 volume
->servers_seq
++;
350 volume
->update_at
= ktime_get_real_seconds() + afs_volume_record_life
;
351 write_unlock(&volume
->servers_lock
);
354 afs_put_serverlist(volume
->cell
->net
, discard
);
358 _leave(" = %d", ret
);
363 * Make sure the volume record is up to date.
365 int afs_check_volume_status(struct afs_volume
*volume
, struct afs_operation
*op
)
367 int ret
, retries
= 0;
372 if (test_bit(AFS_VOLUME_WAIT
, &volume
->flags
))
374 if (volume
->update_at
<= ktime_get_real_seconds() ||
375 test_bit(AFS_VOLUME_NEEDS_UPDATE
, &volume
->flags
))
381 if (!test_and_set_bit_lock(AFS_VOLUME_UPDATING
, &volume
->flags
)) {
382 clear_bit(AFS_VOLUME_NEEDS_UPDATE
, &volume
->flags
);
383 ret
= afs_update_volume_status(volume
, op
->key
);
385 set_bit(AFS_VOLUME_NEEDS_UPDATE
, &volume
->flags
);
386 clear_bit_unlock(AFS_VOLUME_WAIT
, &volume
->flags
);
387 clear_bit_unlock(AFS_VOLUME_UPDATING
, &volume
->flags
);
388 wake_up_bit(&volume
->flags
, AFS_VOLUME_WAIT
);
389 _leave(" = %d", ret
);
394 if (!test_bit(AFS_VOLUME_WAIT
, &volume
->flags
)) {
395 _leave(" = 0 [no wait]");
399 ret
= wait_on_bit(&volume
->flags
, AFS_VOLUME_WAIT
,
400 (op
->flags
& AFS_OPERATION_UNINTR
) ?
401 TASK_UNINTERRUPTIBLE
: TASK_INTERRUPTIBLE
);
402 if (ret
== -ERESTARTSYS
) {
403 _leave(" = %d", ret
);
409 _leave(" = -ESTALE");