diff --git a/fs/afs/cell.c b/fs/afs/cell.c index 47f96be05163cfba99eb335509b86f6fd3771805..9c3b07ba22221f80d5d59751c1fd994765b1b98a 100644 --- a/fs/afs/cell.c +++ b/fs/afs/cell.c @@ -152,8 +152,6 @@ static struct afs_cell *afs_alloc_cell(struct afs_net *net, atomic_set(&cell->usage, 2); INIT_WORK(&cell->manager, afs_manage_cell); - cell->flags = ((1 << AFS_CELL_FL_NOT_READY) | - (1 << AFS_CELL_FL_NO_LOOKUP_YET)); INIT_LIST_HEAD(&cell->proc_volumes); rwlock_init(&cell->proc_lock); rwlock_init(&cell->vl_servers_lock); @@ -170,17 +168,25 @@ static struct afs_cell *afs_alloc_cell(struct afs_net *net, goto parse_failed; } + vllist->source = DNS_RECORD_FROM_CONFIG; + vllist->status = DNS_LOOKUP_NOT_DONE; cell->dns_expiry = TIME64_MAX; } else { ret = -ENOMEM; vllist = afs_alloc_vlserver_list(0); if (!vllist) goto error; + vllist->source = DNS_RECORD_UNAVAILABLE; + vllist->status = DNS_LOOKUP_NOT_DONE; cell->dns_expiry = ktime_get_real_seconds(); } rcu_assign_pointer(cell->vl_servers, vllist); + cell->dns_source = vllist->source; + cell->dns_status = vllist->status; + smp_store_release(&cell->dns_lookup_count, 1); /* vs source/status */ + _leave(" = %p", cell); return cell; @@ -212,6 +218,7 @@ struct afs_cell *afs_lookup_cell(struct afs_net *net, { struct afs_cell *cell, *candidate, *cursor; struct rb_node *parent, **pp; + enum afs_cell_state state; int ret, n; _enter("%s,%s", name, vllist); @@ -271,18 +278,16 @@ struct afs_cell *afs_lookup_cell(struct afs_net *net, wait_for_cell: _debug("wait_for_cell"); - ret = wait_on_bit(&cell->flags, AFS_CELL_FL_NOT_READY, TASK_INTERRUPTIBLE); - smp_rmb(); - - switch (READ_ONCE(cell->state)) { - case AFS_CELL_FAILED: + wait_var_event(&cell->state, + ({ + state = smp_load_acquire(&cell->state); /* vs error */ + state == AFS_CELL_ACTIVE || state == AFS_CELL_FAILED; + })); + + /* Check the state obtained from the wait check. */ + if (state == AFS_CELL_FAILED) { ret = cell->error; goto error; - default: - _debug("weird %u %d", cell->state, cell->error); - goto error; - case AFS_CELL_ACTIVE: - break; } _leave(" = %p [cell]", cell); @@ -364,16 +369,46 @@ int afs_cell_init(struct afs_net *net, const char *rootcell) /* * Update a cell's VL server address list from the DNS. */ -static void afs_update_cell(struct afs_cell *cell) +static int afs_update_cell(struct afs_cell *cell) { - struct afs_vlserver_list *vllist, *old; + struct afs_vlserver_list *vllist, *old = NULL, *p; unsigned int min_ttl = READ_ONCE(afs_cell_min_ttl); unsigned int max_ttl = READ_ONCE(afs_cell_max_ttl); time64_t now, expiry = 0; + int ret = 0; _enter("%s", cell->name); vllist = afs_dns_query(cell, &expiry); + if (IS_ERR(vllist)) { + ret = PTR_ERR(vllist); + + _debug("%s: fail %d", cell->name, ret); + if (ret == -ENOMEM) + goto out_wake; + + ret = -ENOMEM; + vllist = afs_alloc_vlserver_list(0); + if (!vllist) + goto out_wake; + + switch (ret) { + case -ENODATA: + case -EDESTADDRREQ: + vllist->status = DNS_LOOKUP_GOT_NOT_FOUND; + break; + case -EAGAIN: + case -ECONNREFUSED: + vllist->status = DNS_LOOKUP_GOT_TEMP_FAILURE; + break; + default: + vllist->status = DNS_LOOKUP_GOT_LOCAL_FAILURE; + break; + } + } + + _debug("%s: got list %d %d", cell->name, vllist->source, vllist->status); + cell->dns_status = vllist->status; now = ktime_get_real_seconds(); if (min_ttl > max_ttl) @@ -383,46 +418,47 @@ static void afs_update_cell(struct afs_cell *cell) else if (expiry > now + max_ttl) expiry = now + max_ttl; - if (IS_ERR(vllist)) { - switch (PTR_ERR(vllist)) { - case -ENODATA: - case -EDESTADDRREQ: + _debug("%s: status %d", cell->name, vllist->status); + if (vllist->source == DNS_RECORD_UNAVAILABLE) { + switch (vllist->status) { + case DNS_LOOKUP_GOT_NOT_FOUND: /* The DNS said that the cell does not exist or there * weren't any addresses to be had. */ - set_bit(AFS_CELL_FL_NOT_FOUND, &cell->flags); - clear_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags); cell->dns_expiry = expiry; break; - case -EAGAIN: - case -ECONNREFUSED: + case DNS_LOOKUP_BAD: + case DNS_LOOKUP_GOT_LOCAL_FAILURE: + case DNS_LOOKUP_GOT_TEMP_FAILURE: + case DNS_LOOKUP_GOT_NS_FAILURE: default: - set_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags); cell->dns_expiry = now + 10; break; } - - cell->error = -EDESTADDRREQ; } else { - clear_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags); - clear_bit(AFS_CELL_FL_NOT_FOUND, &cell->flags); - - write_lock(&cell->vl_servers_lock); - old = rcu_dereference_protected(cell->vl_servers, true); - rcu_assign_pointer(cell->vl_servers, vllist); cell->dns_expiry = expiry; - write_unlock(&cell->vl_servers_lock); - - afs_put_vlserverlist(cell->net, old); } - if (test_and_clear_bit(AFS_CELL_FL_NO_LOOKUP_YET, &cell->flags)) - wake_up_bit(&cell->flags, AFS_CELL_FL_NO_LOOKUP_YET); + /* Replace the VL server list if the new record has servers or the old + * record doesn't. + */ + write_lock(&cell->vl_servers_lock); + p = rcu_dereference_protected(cell->vl_servers, true); + if (vllist->nr_servers > 0 || p->nr_servers == 0) { + rcu_assign_pointer(cell->vl_servers, vllist); + cell->dns_source = vllist->source; + old = p; + } + write_unlock(&cell->vl_servers_lock); + afs_put_vlserverlist(cell->net, old); - now = ktime_get_real_seconds(); - afs_set_cell_timer(cell->net, cell->dns_expiry - now); - _leave(""); +out_wake: + smp_store_release(&cell->dns_lookup_count, + cell->dns_lookup_count + 1); /* vs source/status */ + wake_up_var(&cell->dns_lookup_count); + _leave(" = %d", ret); + return ret; } /* @@ -493,8 +529,7 @@ void afs_put_cell(struct afs_net *net, struct afs_cell *cell) now = ktime_get_real_seconds(); cell->last_inactive = now; expire_delay = 0; - if (!test_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags) && - !test_bit(AFS_CELL_FL_NOT_FOUND, &cell->flags)) + if (cell->vl_servers->nr_servers) expire_delay = afs_cell_gc_delay; if (atomic_dec_return(&cell->usage) > 1) @@ -625,11 +660,13 @@ static void afs_manage_cell(struct work_struct *work) goto final_destruction; if (cell->state == AFS_CELL_FAILED) goto done; - cell->state = AFS_CELL_UNSET; + smp_store_release(&cell->state, AFS_CELL_UNSET); + wake_up_var(&cell->state); goto again; case AFS_CELL_UNSET: - cell->state = AFS_CELL_ACTIVATING; + smp_store_release(&cell->state, AFS_CELL_ACTIVATING); + wake_up_var(&cell->state); goto again; case AFS_CELL_ACTIVATING: @@ -637,28 +674,29 @@ static void afs_manage_cell(struct work_struct *work) if (ret < 0) goto activation_failed; - cell->state = AFS_CELL_ACTIVE; - smp_wmb(); - clear_bit(AFS_CELL_FL_NOT_READY, &cell->flags); - wake_up_bit(&cell->flags, AFS_CELL_FL_NOT_READY); + smp_store_release(&cell->state, AFS_CELL_ACTIVE); + wake_up_var(&cell->state); goto again; case AFS_CELL_ACTIVE: if (atomic_read(&cell->usage) > 1) { - time64_t now = ktime_get_real_seconds(); - if (cell->dns_expiry <= now && net->live) - afs_update_cell(cell); + if (test_and_clear_bit(AFS_CELL_FL_DO_LOOKUP, &cell->flags)) { + ret = afs_update_cell(cell); + if (ret < 0) + cell->error = ret; + } goto done; } - cell->state = AFS_CELL_DEACTIVATING; + smp_store_release(&cell->state, AFS_CELL_DEACTIVATING); + wake_up_var(&cell->state); goto again; case AFS_CELL_DEACTIVATING: - set_bit(AFS_CELL_FL_NOT_READY, &cell->flags); if (atomic_read(&cell->usage) > 1) goto reverse_deactivation; afs_deactivate_cell(net, cell); - cell->state = AFS_CELL_INACTIVE; + smp_store_release(&cell->state, AFS_CELL_INACTIVE); + wake_up_var(&cell->state); goto again; default: @@ -671,17 +709,13 @@ static void afs_manage_cell(struct work_struct *work) cell->error = ret; afs_deactivate_cell(net, cell); - cell->state = AFS_CELL_FAILED; - smp_wmb(); - if (test_and_clear_bit(AFS_CELL_FL_NOT_READY, &cell->flags)) - wake_up_bit(&cell->flags, AFS_CELL_FL_NOT_READY); + smp_store_release(&cell->state, AFS_CELL_FAILED); /* vs error */ + wake_up_var(&cell->state); goto again; reverse_deactivation: - cell->state = AFS_CELL_ACTIVE; - smp_wmb(); - clear_bit(AFS_CELL_FL_NOT_READY, &cell->flags); - wake_up_bit(&cell->flags, AFS_CELL_FL_NOT_READY); + smp_store_release(&cell->state, AFS_CELL_ACTIVE); + wake_up_var(&cell->state); _leave(" [deact->act]"); return; @@ -741,11 +775,16 @@ void afs_manage_cells(struct work_struct *work) } if (usage == 1) { + struct afs_vlserver_list *vllist; time64_t expire_at = cell->last_inactive; - if (!test_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags) && - !test_bit(AFS_CELL_FL_NOT_FOUND, &cell->flags)) + read_lock(&cell->vl_servers_lock); + vllist = rcu_dereference_protected( + cell->vl_servers, + lockdep_is_held(&cell->vl_servers_lock)); + if (vllist->nr_servers > 0) expire_at += afs_cell_gc_delay; + read_unlock(&cell->vl_servers_lock); if (purging || expire_at <= now) sched_cell = true; else if (expire_at < next_manage) @@ -753,10 +792,8 @@ void afs_manage_cells(struct work_struct *work) } if (!purging) { - if (cell->dns_expiry <= now) + if (test_bit(AFS_CELL_FL_DO_LOOKUP, &cell->flags)) sched_cell = true; - else if (cell->dns_expiry <= next_manage) - next_manage = cell->dns_expiry; } if (sched_cell) diff --git a/fs/afs/internal.h b/fs/afs/internal.h index 74ee0f8ef8ddee1472567930c116787915ab3ded..50d925f0a556a8f5f0f9e915cf3671ddca1db67c 100644 --- a/fs/afs/internal.h +++ b/fs/afs/internal.h @@ -367,13 +367,13 @@ struct afs_cell { time64_t last_inactive; /* Time of last drop of usage count */ atomic_t usage; unsigned long flags; -#define AFS_CELL_FL_NOT_READY 0 /* The cell record is not ready for use */ -#define AFS_CELL_FL_NO_GC 1 /* The cell was added manually, don't auto-gc */ -#define AFS_CELL_FL_NOT_FOUND 2 /* Permanent DNS error */ -#define AFS_CELL_FL_DNS_FAIL 3 /* Failed to access DNS */ -#define AFS_CELL_FL_NO_LOOKUP_YET 4 /* Not completed first DNS lookup yet */ +#define AFS_CELL_FL_NO_GC 0 /* The cell was added manually, don't auto-gc */ +#define AFS_CELL_FL_DO_LOOKUP 1 /* DNS lookup requested */ enum afs_cell_state state; short error; + enum dns_record_source dns_source:8; /* Latest source of data from lookup */ + enum dns_lookup_status dns_status:8; /* Latest status of data from lookup */ + unsigned int dns_lookup_count; /* Counter of DNS lookups */ /* Active fileserver interaction state. */ struct list_head proc_volumes; /* procfs volume list */ diff --git a/fs/afs/vl_rotate.c b/fs/afs/vl_rotate.c index 65629d73ad9dc9f5d21d3c6c785eb1a80b9144cd..3f845489a9f0eba96ae86b657d58170b1ff92df0 100644 --- a/fs/afs/vl_rotate.c +++ b/fs/afs/vl_rotate.c @@ -43,11 +43,29 @@ bool afs_begin_vlserver_operation(struct afs_vl_cursor *vc, struct afs_cell *cel static bool afs_start_vl_iteration(struct afs_vl_cursor *vc) { struct afs_cell *cell = vc->cell; + unsigned int dns_lookup_count; + + if (cell->dns_source == DNS_RECORD_UNAVAILABLE || + cell->dns_expiry <= ktime_get_real_seconds()) { + dns_lookup_count = smp_load_acquire(&cell->dns_lookup_count); + set_bit(AFS_CELL_FL_DO_LOOKUP, &cell->flags); + queue_work(afs_wq, &cell->manager); + + if (cell->dns_source == DNS_RECORD_UNAVAILABLE) { + if (wait_var_event_interruptible( + &cell->dns_lookup_count, + smp_load_acquire(&cell->dns_lookup_count) + != dns_lookup_count) < 0) { + vc->error = -ERESTARTSYS; + return false; + } + } - if (wait_on_bit(&cell->flags, AFS_CELL_FL_NO_LOOKUP_YET, - TASK_INTERRUPTIBLE)) { - vc->error = -ERESTARTSYS; - return false; + /* Status load is ordered after lookup counter load */ + if (cell->dns_source == DNS_RECORD_UNAVAILABLE) { + vc->error = -EDESTADDRREQ; + return false; + } } read_lock(&cell->vl_servers_lock);