// SPDX-License-Identifier: GPL-2.0-or-later /* AFS volume management * * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) */ #include <linux/kernel.h> #include <linux/slab.h> #include "internal.h" unsigned __read_mostly afs_volume_gc_delay = 10; unsigned __read_mostly afs_volume_record_life = 60 * 60; /* * Allocate a volume record and load it up from a vldb record. */ static struct afs_volume *afs_alloc_volume(struct afs_fs_context *params, struct afs_vldb_entry *vldb, unsigned long type_mask) { struct afs_server_list *slist; struct afs_volume *volume; int ret = -ENOMEM, nr_servers = 0, i; for (i = 0; i < vldb->nr_servers; i++) if (vldb->fs_mask[i] & type_mask) nr_servers++; volume = kzalloc(sizeof(struct afs_volume), GFP_KERNEL); if (!volume) goto error_0; volume->vid = vldb->vid[params->type]; volume->update_at = ktime_get_real_seconds() + afs_volume_record_life; volume->cell = afs_get_cell(params->cell); volume->type = params->type; volume->type_force = params->force; volume->name_len = vldb->name_len; atomic_set(&volume->usage, 1); INIT_LIST_HEAD(&volume->proc_link); rwlock_init(&volume->servers_lock); rwlock_init(&volume->cb_v_break_lock); memcpy(volume->name, vldb->name, vldb->name_len + 1); slist = afs_alloc_server_list(params->cell, params->key, vldb, type_mask); if (IS_ERR(slist)) { ret = PTR_ERR(slist); goto error_1; } refcount_set(&slist->usage, 1); volume->servers = slist; return volume; error_1: afs_put_cell(params->net, volume->cell); kfree(volume); error_0: return ERR_PTR(ret); } /* * Look up a VLDB record for a volume. */ static struct afs_vldb_entry *afs_vl_lookup_vldb(struct afs_cell *cell, struct key *key, const char *volname, size_t volnamesz) { struct afs_vldb_entry *vldb = ERR_PTR(-EDESTADDRREQ); struct afs_vl_cursor vc; int ret; if (!afs_begin_vlserver_operation(&vc, cell, key)) return ERR_PTR(-ERESTARTSYS); while (afs_select_vlserver(&vc)) { vldb = afs_vl_get_entry_by_name_u(&vc, volname, volnamesz); } ret = afs_end_vlserver_operation(&vc); return ret < 0 ? ERR_PTR(ret) : vldb; } /* * Look up a volume in the VL server and create a candidate volume record for * it. * * The volume name 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 */ struct afs_volume *afs_create_volume(struct afs_fs_context *params) { struct afs_vldb_entry *vldb; struct afs_volume *volume; unsigned long type_mask = 1UL << params->type; vldb = afs_vl_lookup_vldb(params->cell, params->key, params->volname, params->volnamesz); if (IS_ERR(vldb)) return ERR_CAST(vldb); if (test_bit(AFS_VLDB_QUERY_ERROR, &vldb->flags)) { volume = ERR_PTR(vldb->error); goto error; } /* Make the final decision on the type we want */ volume = ERR_PTR(-ENOMEDIUM); if (params->force) { if (!(vldb->flags & type_mask)) goto error; } else if (test_bit(AFS_VLDB_HAS_RO, &vldb->flags)) { params->type = AFSVL_ROVOL; } else if (test_bit(AFS_VLDB_HAS_RW, &vldb->flags)) { params->type = AFSVL_RWVOL; } else { goto error; } type_mask = 1UL << params->type; volume = afs_alloc_volume(params, vldb, type_mask); error: kfree(vldb); return volume; } /* * Destroy a volume record */ static void afs_destroy_volume(struct afs_net *net, struct afs_volume *volume) { _enter("%p", volume); #ifdef CONFIG_AFS_FSCACHE ASSERTCMP(volume->cache, ==, NULL); #endif afs_put_serverlist(net, volume->servers); afs_put_cell(net, volume->cell); kfree(volume); _leave(" [destroyed]"); } /* * Drop a reference on a volume record. */ void afs_put_volume(struct afs_cell *cell, struct afs_volume *volume) { if (volume) { _enter("%s", volume->name); if (atomic_dec_and_test(&volume->usage)) afs_destroy_volume(cell->net, volume); } } /* * Activate a volume. */ void afs_activate_volume(struct afs_volume *volume) { #ifdef CONFIG_AFS_FSCACHE volume->cache = fscache_acquire_cookie(volume->cell->cache, &afs_volume_cache_index_def, &volume->vid, sizeof(volume->vid), NULL, 0, volume, 0, true); #endif write_lock(&volume->cell->proc_lock); list_add_tail(&volume->proc_link, &volume->cell->proc_volumes); write_unlock(&volume->cell->proc_lock); } /* * Deactivate a volume. */ void afs_deactivate_volume(struct afs_volume *volume) { _enter("%s", volume->name); write_lock(&volume->cell->proc_lock); list_del_init(&volume->proc_link); write_unlock(&volume->cell->proc_lock); #ifdef CONFIG_AFS_FSCACHE fscache_relinquish_cookie(volume->cache, NULL, test_bit(AFS_VOLUME_DELETED, &volume->flags)); volume->cache = NULL; #endif _leave(""); } /* * Query the VL service to update the volume status. */ static int afs_update_volume_status(struct afs_volume *volume, struct key *key) { struct afs_server_list *new, *old, *discard; struct afs_vldb_entry *vldb; char idbuf[16]; int ret, idsz; _enter(""); /* We look up an ID by passing it as a decimal string in the * operation's name parameter. */ idsz = sprintf(idbuf, "%llu", volume->vid); vldb = afs_vl_lookup_vldb(volume->cell, key, idbuf, idsz); if (IS_ERR(vldb)) { ret = PTR_ERR(vldb); goto error; } /* See if the volume got renamed. */ if (vldb->name_len != volume->name_len || memcmp(vldb->name, volume->name, vldb->name_len) != 0) { /* TODO: Use RCU'd string. */ memcpy(volume->name, vldb->name, AFS_MAXVOLNAME); volume->name_len = vldb->name_len; } /* See if the volume's server list got updated. */ new = afs_alloc_server_list(volume->cell, key, vldb, (1 << volume->type)); if (IS_ERR(new)) { ret = PTR_ERR(new); goto error_vldb; } write_lock(&volume->servers_lock); discard = new; old = volume->servers; if (afs_annotate_server_list(new, old)) { new->seq = volume->servers_seq + 1; volume->servers = new; smp_wmb(); volume->servers_seq++; discard = old; } volume->update_at = ktime_get_real_seconds() + afs_volume_record_life; clear_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags); write_unlock(&volume->servers_lock); ret = 0; afs_put_serverlist(volume->cell->net, discard); error_vldb: kfree(vldb); error: _leave(" = %d", ret); return ret; } /* * Make sure the volume record is up to date. */ int afs_check_volume_status(struct afs_volume *volume, struct key *key) { time64_t now = ktime_get_real_seconds(); int ret, retries = 0; _enter(""); if (volume->update_at <= now) set_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags); retry: if (!test_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags) && !test_bit(AFS_VOLUME_WAIT, &volume->flags)) { _leave(" = 0"); return 0; } if (!test_and_set_bit_lock(AFS_VOLUME_UPDATING, &volume->flags)) { ret = afs_update_volume_status(volume, key); clear_bit_unlock(AFS_VOLUME_WAIT, &volume->flags); clear_bit_unlock(AFS_VOLUME_UPDATING, &volume->flags); wake_up_bit(&volume->flags, AFS_VOLUME_WAIT); _leave(" = %d", ret); return ret; } if (!test_bit(AFS_VOLUME_WAIT, &volume->flags)) { _leave(" = 0 [no wait]"); return 0; } ret = wait_on_bit(&volume->flags, AFS_VOLUME_WAIT, TASK_INTERRUPTIBLE); if (ret == -ERESTARTSYS) { _leave(" = %d", ret); return ret; } retries++; if (retries == 4) { _leave(" = -ESTALE"); return -ESTALE; } goto retry; }