linux/fs/dlm/ast.c
Alexander Aring ad191e0eee dlm: fix user space lock decision to copy lvb
This patch fixes the copy lvb decision for user space lock requests.
Checking dlm_lvb_operations is done earlier, where granted/requested
lock modes are available to use in the matrix.

The decision had been moved to the wrong location, where granted mode
and requested mode where the same, which causes the dlm_lvb_operations
matix to produce the wrong copy decision. For PW or EX requests, the
caller could get invalid lvb data.

Fixes: 61bed0baa4 ("fs: dlm: use a non-static queue for callbacks")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
2024-04-01 13:31:12 -05:00

286 lines
7.0 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/******************************************************************************
*******************************************************************************
**
** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
** Copyright (C) 2004-2010 Red Hat, Inc. All rights reserved.
**
**
*******************************************************************************
******************************************************************************/
#include <trace/events/dlm.h>
#include "dlm_internal.h"
#include "lvb_table.h"
#include "memory.h"
#include "lock.h"
#include "user.h"
#include "ast.h"
void dlm_release_callback(struct kref *ref)
{
struct dlm_callback *cb = container_of(ref, struct dlm_callback, ref);
dlm_free_cb(cb);
}
void dlm_callback_set_last_ptr(struct dlm_callback **from,
struct dlm_callback *to)
{
if (*from)
kref_put(&(*from)->ref, dlm_release_callback);
if (to)
kref_get(&to->ref);
*from = to;
}
int dlm_enqueue_lkb_callback(struct dlm_lkb *lkb, uint32_t flags, int mode,
int status, uint32_t sbflags)
{
struct dlm_ls *ls = lkb->lkb_resource->res_ls;
int rv = DLM_ENQUEUE_CALLBACK_SUCCESS;
struct dlm_callback *cb;
int copy_lvb = 0;
int prev_mode;
if (flags & DLM_CB_BAST) {
/* if cb is a bast, it should be skipped if the blocking mode is
* compatible with the last granted mode
*/
if (lkb->lkb_last_cast) {
if (dlm_modes_compat(mode, lkb->lkb_last_cast->mode)) {
log_debug(ls, "skip %x bast mode %d for cast mode %d",
lkb->lkb_id, mode,
lkb->lkb_last_cast->mode);
goto out;
}
}
/*
* Suppress some redundant basts here, do more on removal.
* Don't even add a bast if the callback just before it
* is a bast for the same mode or a more restrictive mode.
* (the addional > PR check is needed for PR/CW inversion)
*/
if (lkb->lkb_last_cb && lkb->lkb_last_cb->flags & DLM_CB_BAST) {
prev_mode = lkb->lkb_last_cb->mode;
if ((prev_mode == mode) ||
(prev_mode > mode && prev_mode > DLM_LOCK_PR)) {
log_debug(ls, "skip %x add bast mode %d for bast mode %d",
lkb->lkb_id, mode, prev_mode);
goto out;
}
}
} else if (flags & DLM_CB_CAST) {
if (test_bit(DLM_DFL_USER_BIT, &lkb->lkb_dflags)) {
if (lkb->lkb_last_cast)
prev_mode = lkb->lkb_last_cb->mode;
else
prev_mode = -1;
if (!status && lkb->lkb_lksb->sb_lvbptr &&
dlm_lvb_operations[prev_mode + 1][mode + 1])
copy_lvb = 1;
}
}
cb = dlm_allocate_cb();
if (!cb) {
rv = DLM_ENQUEUE_CALLBACK_FAILURE;
goto out;
}
cb->flags = flags;
cb->mode = mode;
cb->sb_status = status;
cb->sb_flags = (sbflags & 0x000000FF);
cb->copy_lvb = copy_lvb;
kref_init(&cb->ref);
if (!test_and_set_bit(DLM_IFL_CB_PENDING_BIT, &lkb->lkb_iflags))
rv = DLM_ENQUEUE_CALLBACK_NEED_SCHED;
list_add_tail(&cb->list, &lkb->lkb_callbacks);
if (flags & DLM_CB_CAST)
dlm_callback_set_last_ptr(&lkb->lkb_last_cast, cb);
dlm_callback_set_last_ptr(&lkb->lkb_last_cb, cb);
out:
return rv;
}
int dlm_dequeue_lkb_callback(struct dlm_lkb *lkb, struct dlm_callback **cb)
{
/* oldest undelivered cb is callbacks first entry */
*cb = list_first_entry_or_null(&lkb->lkb_callbacks,
struct dlm_callback, list);
if (!*cb)
return DLM_DEQUEUE_CALLBACK_EMPTY;
/* remove it from callbacks so shift others down */
list_del(&(*cb)->list);
if (list_empty(&lkb->lkb_callbacks))
return DLM_DEQUEUE_CALLBACK_LAST;
return DLM_DEQUEUE_CALLBACK_SUCCESS;
}
void dlm_add_cb(struct dlm_lkb *lkb, uint32_t flags, int mode, int status,
uint32_t sbflags)
{
struct dlm_ls *ls = lkb->lkb_resource->res_ls;
int rv;
if (test_bit(DLM_DFL_USER_BIT, &lkb->lkb_dflags)) {
dlm_user_add_ast(lkb, flags, mode, status, sbflags);
return;
}
spin_lock(&lkb->lkb_cb_lock);
rv = dlm_enqueue_lkb_callback(lkb, flags, mode, status, sbflags);
switch (rv) {
case DLM_ENQUEUE_CALLBACK_NEED_SCHED:
kref_get(&lkb->lkb_ref);
spin_lock(&ls->ls_cb_lock);
if (test_bit(LSFL_CB_DELAY, &ls->ls_flags)) {
list_add(&lkb->lkb_cb_list, &ls->ls_cb_delay);
} else {
queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
}
spin_unlock(&ls->ls_cb_lock);
break;
case DLM_ENQUEUE_CALLBACK_FAILURE:
WARN_ON_ONCE(1);
break;
case DLM_ENQUEUE_CALLBACK_SUCCESS:
break;
default:
WARN_ON_ONCE(1);
break;
}
spin_unlock(&lkb->lkb_cb_lock);
}
void dlm_callback_work(struct work_struct *work)
{
struct dlm_lkb *lkb = container_of(work, struct dlm_lkb, lkb_cb_work);
struct dlm_ls *ls = lkb->lkb_resource->res_ls;
void (*castfn) (void *astparam);
void (*bastfn) (void *astparam, int mode);
struct dlm_callback *cb;
int rv;
spin_lock(&lkb->lkb_cb_lock);
rv = dlm_dequeue_lkb_callback(lkb, &cb);
if (WARN_ON_ONCE(rv == DLM_DEQUEUE_CALLBACK_EMPTY)) {
clear_bit(DLM_IFL_CB_PENDING_BIT, &lkb->lkb_iflags);
spin_unlock(&lkb->lkb_cb_lock);
goto out;
}
spin_unlock(&lkb->lkb_cb_lock);
for (;;) {
castfn = lkb->lkb_astfn;
bastfn = lkb->lkb_bastfn;
if (cb->flags & DLM_CB_BAST) {
trace_dlm_bast(ls, lkb, cb->mode);
lkb->lkb_last_bast_time = ktime_get();
lkb->lkb_last_bast_mode = cb->mode;
bastfn(lkb->lkb_astparam, cb->mode);
} else if (cb->flags & DLM_CB_CAST) {
lkb->lkb_lksb->sb_status = cb->sb_status;
lkb->lkb_lksb->sb_flags = cb->sb_flags;
trace_dlm_ast(ls, lkb);
lkb->lkb_last_cast_time = ktime_get();
castfn(lkb->lkb_astparam);
}
kref_put(&cb->ref, dlm_release_callback);
spin_lock(&lkb->lkb_cb_lock);
rv = dlm_dequeue_lkb_callback(lkb, &cb);
if (rv == DLM_DEQUEUE_CALLBACK_EMPTY) {
clear_bit(DLM_IFL_CB_PENDING_BIT, &lkb->lkb_iflags);
spin_unlock(&lkb->lkb_cb_lock);
break;
}
spin_unlock(&lkb->lkb_cb_lock);
}
out:
/* undo kref_get from dlm_add_callback, may cause lkb to be freed */
dlm_put_lkb(lkb);
}
int dlm_callback_start(struct dlm_ls *ls)
{
ls->ls_callback_wq = alloc_workqueue("dlm_callback",
WQ_HIGHPRI | WQ_MEM_RECLAIM, 0);
if (!ls->ls_callback_wq) {
log_print("can't start dlm_callback workqueue");
return -ENOMEM;
}
return 0;
}
void dlm_callback_stop(struct dlm_ls *ls)
{
if (ls->ls_callback_wq)
destroy_workqueue(ls->ls_callback_wq);
}
void dlm_callback_suspend(struct dlm_ls *ls)
{
if (ls->ls_callback_wq) {
spin_lock(&ls->ls_cb_lock);
set_bit(LSFL_CB_DELAY, &ls->ls_flags);
spin_unlock(&ls->ls_cb_lock);
flush_workqueue(ls->ls_callback_wq);
}
}
#define MAX_CB_QUEUE 25
void dlm_callback_resume(struct dlm_ls *ls)
{
struct dlm_lkb *lkb, *safe;
int count = 0, sum = 0;
bool empty;
if (!ls->ls_callback_wq)
return;
more:
spin_lock(&ls->ls_cb_lock);
list_for_each_entry_safe(lkb, safe, &ls->ls_cb_delay, lkb_cb_list) {
list_del_init(&lkb->lkb_cb_list);
queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
count++;
if (count == MAX_CB_QUEUE)
break;
}
empty = list_empty(&ls->ls_cb_delay);
if (empty)
clear_bit(LSFL_CB_DELAY, &ls->ls_flags);
spin_unlock(&ls->ls_cb_lock);
sum += count;
if (!empty) {
count = 0;
cond_resched();
goto more;
}
if (sum)
log_rinfo(ls, "%s %d", __func__, sum);
}