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-rw-r--r--fs/afs/volume.c452
1 files changed, 452 insertions, 0 deletions
diff --git a/fs/afs/volume.c b/fs/afs/volume.c
new file mode 100644
index 000000000..1c9144e3e
--- /dev/null
+++ b/fs/afs/volume.c
@@ -0,0 +1,452 @@
+// 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"
+
+static unsigned __read_mostly afs_volume_record_life = 60 * 60;
+
+/*
+ * Insert a volume into a cell. If there's an existing volume record, that is
+ * returned instead with a ref held.
+ */
+static struct afs_volume *afs_insert_volume_into_cell(struct afs_cell *cell,
+ struct afs_volume *volume)
+{
+ struct afs_volume *p;
+ struct rb_node *parent = NULL, **pp;
+
+ write_seqlock(&cell->volume_lock);
+
+ pp = &cell->volumes.rb_node;
+ while (*pp) {
+ parent = *pp;
+ p = rb_entry(parent, struct afs_volume, cell_node);
+ if (p->vid < volume->vid) {
+ pp = &(*pp)->rb_left;
+ } else if (p->vid > volume->vid) {
+ pp = &(*pp)->rb_right;
+ } else {
+ if (afs_try_get_volume(p, afs_volume_trace_get_cell_insert)) {
+ volume = p;
+ goto found;
+ }
+
+ set_bit(AFS_VOLUME_RM_TREE, &volume->flags);
+ rb_replace_node_rcu(&p->cell_node, &volume->cell_node, &cell->volumes);
+ }
+ }
+
+ rb_link_node_rcu(&volume->cell_node, parent, pp);
+ rb_insert_color(&volume->cell_node, &cell->volumes);
+ hlist_add_head_rcu(&volume->proc_link, &cell->proc_volumes);
+
+found:
+ write_sequnlock(&cell->volume_lock);
+ return volume;
+
+}
+
+static void afs_remove_volume_from_cell(struct afs_volume *volume)
+{
+ struct afs_cell *cell = volume->cell;
+
+ if (!hlist_unhashed(&volume->proc_link)) {
+ trace_afs_volume(volume->vid, refcount_read(&cell->ref),
+ afs_volume_trace_remove);
+ write_seqlock(&cell->volume_lock);
+ hlist_del_rcu(&volume->proc_link);
+ if (!test_and_set_bit(AFS_VOLUME_RM_TREE, &volume->flags))
+ rb_erase(&volume->cell_node, &cell->volumes);
+ write_sequnlock(&cell->volume_lock);
+ }
+}
+
+/*
+ * 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, afs_cell_trace_get_vol);
+ volume->type = params->type;
+ volume->type_force = params->force;
+ volume->name_len = vldb->name_len;
+
+ refcount_set(&volume->ref, 1);
+ INIT_HLIST_NODE(&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);
+ rcu_assign_pointer(volume->servers, slist);
+ trace_afs_volume(volume->vid, 1, afs_volume_trace_alloc);
+ return volume;
+
+error_1:
+ afs_put_cell(volume->cell, afs_cell_trace_put_vol);
+ kfree(volume);
+error_0:
+ return ERR_PTR(ret);
+}
+
+/*
+ * Look up or allocate a volume record.
+ */
+static struct afs_volume *afs_lookup_volume(struct afs_fs_context *params,
+ struct afs_vldb_entry *vldb,
+ unsigned long type_mask)
+{
+ struct afs_volume *candidate, *volume;
+
+ candidate = afs_alloc_volume(params, vldb, type_mask);
+ if (IS_ERR(candidate))
+ return candidate;
+
+ volume = afs_insert_volume_into_cell(params->cell, candidate);
+ if (volume != candidate)
+ afs_put_volume(params->net, candidate, afs_volume_trace_put_cell_dup);
+ return volume;
+}
+
+/*
+ * 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_lookup_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_remove_volume_from_cell(volume);
+ afs_put_serverlist(net, rcu_access_pointer(volume->servers));
+ afs_put_cell(volume->cell, afs_cell_trace_put_vol);
+ trace_afs_volume(volume->vid, refcount_read(&volume->ref),
+ afs_volume_trace_free);
+ kfree_rcu(volume, rcu);
+
+ _leave(" [destroyed]");
+}
+
+/*
+ * Try to get a reference on a volume record.
+ */
+bool afs_try_get_volume(struct afs_volume *volume, enum afs_volume_trace reason)
+{
+ int r;
+
+ if (__refcount_inc_not_zero(&volume->ref, &r)) {
+ trace_afs_volume(volume->vid, r + 1, reason);
+ return true;
+ }
+ return false;
+}
+
+/*
+ * Get a reference on a volume record.
+ */
+struct afs_volume *afs_get_volume(struct afs_volume *volume,
+ enum afs_volume_trace reason)
+{
+ if (volume) {
+ int r;
+
+ __refcount_inc(&volume->ref, &r);
+ trace_afs_volume(volume->vid, r + 1, reason);
+ }
+ return volume;
+}
+
+
+/*
+ * Drop a reference on a volume record.
+ */
+void afs_put_volume(struct afs_net *net, struct afs_volume *volume,
+ enum afs_volume_trace reason)
+{
+ if (volume) {
+ afs_volid_t vid = volume->vid;
+ bool zero;
+ int r;
+
+ zero = __refcount_dec_and_test(&volume->ref, &r);
+ trace_afs_volume(vid, r - 1, reason);
+ if (zero)
+ afs_destroy_volume(net, volume);
+ }
+}
+
+/*
+ * Activate a volume.
+ */
+int afs_activate_volume(struct afs_volume *volume)
+{
+#ifdef CONFIG_AFS_FSCACHE
+ struct fscache_volume *vcookie;
+ char *name;
+
+ name = kasprintf(GFP_KERNEL, "afs,%s,%llx",
+ volume->cell->name, volume->vid);
+ if (!name)
+ return -ENOMEM;
+
+ vcookie = fscache_acquire_volume(name, NULL, NULL, 0);
+ if (IS_ERR(vcookie)) {
+ if (vcookie != ERR_PTR(-EBUSY)) {
+ kfree(name);
+ return PTR_ERR(vcookie);
+ }
+ pr_err("AFS: Cache volume key already in use (%s)\n", name);
+ vcookie = NULL;
+ }
+ volume->cache = vcookie;
+ kfree(name);
+#endif
+ return 0;
+}
+
+/*
+ * Deactivate a volume.
+ */
+void afs_deactivate_volume(struct afs_volume *volume)
+{
+ _enter("%s", volume->name);
+
+#ifdef CONFIG_AFS_FSCACHE
+ fscache_relinquish_volume(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 = rcu_dereference_protected(volume->servers,
+ lockdep_is_held(&volume->servers_lock));
+ if (afs_annotate_server_list(new, old)) {
+ new->seq = volume->servers_seq + 1;
+ rcu_assign_pointer(volume->servers, new);
+ smp_wmb();
+ volume->servers_seq++;
+ discard = old;
+ }
+
+ volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
+ 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 afs_operation *op)
+{
+ int ret, retries = 0;
+
+ _enter("");
+
+retry:
+ if (test_bit(AFS_VOLUME_WAIT, &volume->flags))
+ goto wait;
+ if (volume->update_at <= ktime_get_real_seconds() ||
+ test_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags))
+ goto update;
+ _leave(" = 0");
+ return 0;
+
+update:
+ if (!test_and_set_bit_lock(AFS_VOLUME_UPDATING, &volume->flags)) {
+ clear_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
+ ret = afs_update_volume_status(volume, op->key);
+ if (ret < 0)
+ set_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
+ 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;
+ }
+
+wait:
+ if (!test_bit(AFS_VOLUME_WAIT, &volume->flags)) {
+ _leave(" = 0 [no wait]");
+ return 0;
+ }
+
+ ret = wait_on_bit(&volume->flags, AFS_VOLUME_WAIT,
+ (op->flags & AFS_OPERATION_UNINTR) ?
+ TASK_UNINTERRUPTIBLE : TASK_INTERRUPTIBLE);
+ if (ret == -ERESTARTSYS) {
+ _leave(" = %d", ret);
+ return ret;
+ }
+
+ retries++;
+ if (retries == 4) {
+ _leave(" = -ESTALE");
+ return -ESTALE;
+ }
+ goto retry;
+}